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  • 1995-1999  (1.665)
  • 1940-1944
  • 1900-1904
  • 1890-1899  (1.494)
  • 1860-1869  (371)
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Schlagwörter
  • 101
    ISSN: 1432-1106
    Schlagwort(e): Key words Suprathreshold heat pain ; Adapting temperature ; Temporal parameters ; Spinal dorsal horn neuron ; Descending control ; Rat ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The influence of stimulus temperature rise rate (2.5ºC/s, 5.0ºC/s, and 10.0ºC/s), adapting (baseline) temperature (25ºC, 30ºC, and 35ºC), and duration of peak stimulus temperature (1.0 s, 2.5 s, 5.0 s, and 10.0 s) on responses evoked by noxious heat stimuli of suprathreshold intensity was studied in wide dynamic range (WDR) neurons of the rat spinal dorsal horn. The spinal neuronal responses were compared with human psychophysical data obtained using the same stimuli. Noxious heat stimuli with a peak temperature of 54ºC were applied with a contact thermostimulator to the glabrous skin of the hindfoot in rats or to the palmar skin in humans. With the highest ramp rate and the highest adapting temperature, the sensory and spinal neuronal response latencies were decreased more than expected on the basis of the change in physical parameters of the stimulus. The magnitudes of sensory and spinal neuronal response were independent of the stimulus ramp rate, whereas pain magnitude estimates and spinal neuronal impulse counts evoked by the same peak stimulus temperature were increased with an increase in the adapting stimulus temperature. The onset latencies of pain reactions and spinal neuronal responses were independent of the peak stimulus duration, whereas the latency of the maximum discharge in spinal neurons increased with prolongation of the peak stimulus. The sensory magnitude estimate of pain and the neuronal impulse count were increased with increase in stimulus duration. Following spinalization, the spinal neuronal responses were stronger and the stimulus duration-dependent increase in the impulse count developed faster. Moreover, the peak frequency of spinal neuronal response increased significantly with prolongation of the heat stimuli after spinalization, but not in animals with an intact spinal cord. The results indicate that stimulus rise rate, stimulus duration, and the adapting temperature are important factors in determining the sensory and spinal neuronal responses to high-intensity heat stimuli. The changes in the total impulse counts evoked by varying supraliminal heat stimuli in spinal dorsal horn WDR neurons corresponded well with the changes in pain magnitude estimates in humans. Also, the changes in spinal neuronal response onset latencies were accompanied by corresponding changes in onset latencies of human pain reactions but not with pain magnitude estimates. The effect of spinalization indicated that descending pathways control not only the response magnitude in the spinal dorsal horn WDR neurons but also the temporal characteristics of the spinal neuronal response.
    Materialart: Digitale Medien
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  • 102
    Digitale Medien
    Digitale Medien
    Springer
    European journal of pediatrics 158 (1999), S. 971-974 
    ISSN: 1432-1076
    Schlagwort(e): Keywords Liver ; Steatosis ; HIV ; AIDS ; Children
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Thirty HIV-infected children were cross-sectionally examined for morphologic hepatic abnormalities, using ultrasonography or histology. Abdominal ultrasonography was performed in 27 children. The liver structure was normal in four patients, one of whom had moderate symptoms of the HIV infection and three of them severe symptoms. Abnormal liver structure, compatible with hepatic steatosis, was found in 23 (85%) patients. Five of them were in an early stage of the HIV infection (category N or A), three patients were ranked in category B and 15 patients in category C. Histological examination of the liver was performed in 11 children and steatosis was documented in ten (91%). In seven (70%) of these ten children steatosis had been suspected by ultrasonography. In conclusion, steatosis is common in HIV-infected children. It is non-specific and has no impact on disease, diagnostic evaluation or management. Conclusion Ultrasonography is a sensitive, accurate, non-invasive screening tool. It is more reliable than liver function tests.
    Materialart: Digitale Medien
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  • 103
    Digitale Medien
    Digitale Medien
    Springer
    European journal of pediatrics 158 (1999), S. 12-17 
    ISSN: 1432-1076
    Schlagwort(e): Key words Alternative medicine ; Complementary therapies ; Critical care ; Children
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The interest in alternative medicine (AM) is growing. In the USA and Canada, studies showed that 34% of adults and 11% of children use AM. In a prospective cohort study, we investigated the interest in AM among parents of critically ill children in the paediatric Intensive Care Unit (ICU) of a university hospital. From January 1996 to April 1997, we distributed questionnaires to the parents of critically ill children. These strictly anonymous questionnaires were completed at home and returned by mail. Exclusion criteria were short (〈1 day) or repeated hospitalizations, and insufficient proficiency of the German language. The inclusion criteria were fulfilled by 591 patients; 561 received the questionnaire (95%) and 289 (52%) were returned. Of the respondents, 70% would appreciate AM as a complementary therapy on the ICU, 23% found AM equally or more important than conventional medicine whereas only 7% regarded AM as unimportant. On the ICU, 18% used AM; surprisingly 41% of them did not discuss it with physicians or nurses. An additional 21% would have liked to use AM, but did not do so. Typically, AM-users administered AM also at home to their children and themselves. Their children were however, older. Conclusions A substantial proportion of parents used measures of alternative medicine in the intensive care unit, or would have like to do so. However, few had the confidence to discuss this wish with the medical personal. This suggests that alternative medicine is of great interest, even on an intensive care unit. Nevertheless, discussion about alternative medicine seems to be taboo in doctor-patient relations.
    Materialart: Digitale Medien
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  • 104
    ISSN: 1432-1076
    Schlagwort(e): Key words Mild head injury ; Fractured bone ; Late sequelae ; Children
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Two years after an accident resulting in either a mild head injury or a fractured bone, two groups of 22 children each, aged 4–14 years, were examined for the existence of any neurobehavioural symptoms by means of a standardized questionnaire filled out by their caretakers. Selection of the children was based on reports of the Accident and Emergency Department in 1 year. Significantly more symptoms were reported after mild head injury. The main symptoms reported were headache, dizziness, fatigue and memory problems. The total number of symptoms in the children with mild head injury exceeded four times this in the group of children with a fractured bone. Conclusion Even 2 years after a mild head injury there are still residual symptoms in daily life.
    Materialart: Digitale Medien
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  • 105
    Digitale Medien
    Digitale Medien
    Springer
    European journal of pediatrics 158 (1999), S. S117 
    ISSN: 1432-1076
    Schlagwort(e): Key words Stroke ; Coagulation ; Children
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Many studies have shown a high percentage of venous thromboses in children to be associated with haematological disorders. However, studies assessing the influence of haemostaseological disorders on paediatric stroke are rare. We compared 26 children with cerebral infarction (median age 2 months, range 0–16.2 years) and 17 with venous thrombosis (median age 4.5 years, range 0–17 years) with regard to prothrombotic risk factors. Prothrombotic disorders were found in 8 out of 26 patients with cerebral infarction (FV Leiden mutation: n = 4; protein C deficiency: n = 1; FV Leiden mutation + protein C deficiency: n = 2; prothrombin mutation G20210A: n = 1) and in 13 out of 17 with venous thrombosis (FV Leiden mutation n = 3; protein C deficiency n = 5; elevated HRGP + PAI: n = 1; combined deficiency of AT, protein C and plasminogen: n = 1; F XII deficiency: n = 1; lupus anticoagulans n = 1; FV Leiden + F XII deficiency + lupus anticoagulans + PAI: n = 1). Comparison of these prevalences with those of 150 healthy paediatric controls showed in children with FV Leiden mutation and/or protein C deficiency an increased risk of cerebral infarction (patients vs. controls: 26.9% vs. 6%; OR 5.77; 95%-CI 1.92–17.3; P = 0.0031) as well as of venous thrombosis (53% vs. 5.3% 19.9; 95%-CI 6–65.6; P 〈 0.0001). This result is in contrast with reports on thrombophilia in cerebral infarction in adult patients. Conclusion Our results indicate that FV Leiden mutation and protein C deficiency may contribute to the multifactorial aetiology of stroke in early childhood.
    Materialart: Digitale Medien
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  • 106
    Digitale Medien
    Digitale Medien
    Springer
    European journal of pediatrics 158 (1999), S. 362-366 
    ISSN: 1432-1076
    Schlagwort(e): Key words Type 1 diabetes ; Children ; Risk factors ; Case control ; Environmental
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The aim of this study was to investigate environmental risk factors in the development of type 1 diabetes mellitus in a population-based case-control study. Parents of all patients with manifestation of type 1 diabetes between 1989 and 1994 in Vienna were asked to complete a questionnaire (n = 114). Control children (n = 495), matched for age and sex, were randomly recruited from all schools in Vienna. Fathers of diabetic children were significantly older at the time their children were born than fathers of control children (P = 0.015). Children with diabetes were more likely to be second- or third-born children (P 〈 0.05) and fewer went to kindergarten than the control group children (P = 0.007). No significant difference in duration of gestation, percentage of delivery by caesarean section, birth weight or length was found. Neonatal jaundice was more often observed in the patient group (P = 0.038). Breast feeding was reported by 82.7% of mothers of diabetic children and by 81% of mothers of control children, and the duration of breast feeding was longer in patients than in controls (n.s.). Conclusion In our study, the development of type 1 diabetes mellitus was associated with higher paternal age and neonatal jaundice. No correlation could be found with dietary intake of cow's milk products in early infancy, vaccination and other environmental factors.
    Materialart: Digitale Medien
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  • 107
    Digitale Medien
    Digitale Medien
    Springer
    European journal of pediatrics 158 (1999), S. 24-28 
    ISSN: 1432-1076
    Schlagwort(e): Key words Hashimoto thyroiditis ; Graves disease ; Children ; TSH function-blocking antibody ; Cytotoxic antibody
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In a cross-sectional study, 29 children aged between 1 month and 15.3 years (average age 6.8 years) born to mothers with Graves disease or Hashimoto thyroiditis were examined clinically, biochemically, and by sonography of the thyroid gland. At the time of examination all children were clinically euthyroid. Tests of thyroid peroxidase antibody, thyroglobulin antibody, TSH receptor antibody and free thyroxine (fT4) gave normal results. In 3 children subclinical hypothyroidism with elevated TSH and normal fT4 concentrations were found; one of these children had a minor decrease of total thyroxine. Three children with otherwise normal test results had marginally elevated tri-iodothyronine concentrations. Increased antibody titres were present in 8 out of 29 children. TSH function-blocking antibodies were elevated in 8 cases. In addition, cytotoxic antibodies were found in one of the children. The distribution pattern of antibodies was different in each child and unrelated to the type of maternal thyroid disease. Conclusion Children of mothers with auto-immune thyroid disease often have thyroid antibodies without signs of thyroid disease. Whether antibody-positive children have an increased risk of developing thyroid disorders later in life must be examined in a longitudinal study.
    Materialart: Digitale Medien
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  • 108
    ISSN: 1432-1076
    Schlagwort(e): Key words Gastro-intestinal bleeding ; Children ; Jejunal leiomyoma ; Neurofibromatosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Gastro-intestinal bleeding is an uncommon presentation in children with neurofibromatosis. Gastro-intestinal involvement caused by jejunal leiomyoma has only been described in adults. To the best of our knowledge, this is the first paediatric case of jejunal leiomyoma associated with neurofibromatosis. We present a 10-year-old girl with a 9-month history of anaemia and low gastro-intestinal bleeding. Abdominal sonography and small bowel series showed a submucosal mass in the proximal jejunum. On surgery, a submucosal tumour was excised and histological examination suggested a diagnosis of “smooth muscle tumour of undetermined malignant potential”. There were no recurrence of symptoms for 4 years after the operation. Conclusion Jejunal leiomyoma should be considered in a child with neurofibromatosis presenting with gastro-intestinal bleeding.
    Materialart: Digitale Medien
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  • 109
    ISSN: 1432-1076
    Schlagwort(e): Key words Respiratory chain ; Mitochondria ; Children ; Infancy ; Liver failure ; AbbreviationsMRCD mitochondrial respiratory chain disease ; OLT orthotopic ; liver transplantation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Mitochondrial respiratory chain disease may lead to neonatal or late onset liver failure, requiring liver transplantation. In rare cases, the disease is restricted to the liver and the patient is cured after surgery. More frequently, other organs are simultaneously involved and neuromuscular or other extra-hepatic symptoms may pre-exist, or appear in the post-transplant follow up. Pre-transplant evaluation should aim to rule out neurological disease, which may be difficult to differentiate from signs accompanying liver insufficiency. Cerebrospinal fluid lactic acid levels, compared to blood lactate, may be suggestive of central nervous system involvement. Of 11 cases with respiratory chain disorders who had liver transplantation in various centres, 4 are alive and well on follow up, and 6 died, three of them having developed neurological disease post orthotopic liver transplantation. All three patients with initial liver and gastro-intestinal disease died early after transplantation, indicating that these may be poor candidates for this procedure. Conclusion Liver transplantation is feasible in hepatic respiratory chain disorders, but extra-hepatic disease should be ruled out before transplantation. Extra-hepatic manifestations may, however, appear and cause patient death despite successful transplantation.
    Materialart: Digitale Medien
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  • 110
    Digitale Medien
    Digitale Medien
    Springer
    European journal of pediatrics 158 (1999), S. S085 
    ISSN: 1432-1076
    Schlagwort(e): Key wordsα1-Antitrypsin ; Liver disease ; Liver transplantation ; Children ; AbbreviationsAATα1-antitrypsin deficiency ; OLT orthotopic liver transplantation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Only a minority of infants born with α1-antitrypsin deficiency will develop serious liver disease during childhood, mostly but not always after neonatal cholestasis. Early prognosis is difficult and all children have to be followed up carefully. The liver disease progresses with varying speed and it lacks specific features. At the time of liver transplantation the young patients have no pulmonary disease induced by the deficiency and in those with renal involvement, the kidney problems can mostly be dealt with by conservative therapy. The peri- and postoperative care of the patients who undergo liver transplantation does not differ from the usual routines.
    Materialart: Digitale Medien
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  • 111
    Digitale Medien
    Digitale Medien
    Springer
    European journal of pediatrics 158 (1999), S. 298-301 
    ISSN: 1432-1076
    Schlagwort(e): Key words Isolated ; Sphenoid ; Sinusitis ; Children
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Acute isolated infectious sphenoiditis is an uncommon, potentially dangerous condition which is often misdiagnosed because of its nonspecific symptoms and paucity of clinical signs. We present eight children with isolated sphenoiditis who were managed in our medical centre during the last 2 years and review the literature. All the patients were adolescents or pre-adolescents and all experienced moderate to severe refractory oppressive headache. Four had a history of sinusitis or allergic rhinitis. None had fever or any other directing clinical sign. Diagnosis was made by cranial computer tomography. All were treated with antibiotics and recovered completely without infectious or neurological complications. Conclusion Acute isolated infectious sphenoiditis should be considered in adolescents and pre-adolescents who present with constant moderate to severe oppressive headache. Awareness of this entity will enable early diagnosis and initiation of antibiotic treatment which is essential to avoid complications and surgical intervention.
    Materialart: Digitale Medien
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  • 112
    ISSN: 1432-1076
    Schlagwort(e): Key words Heparin treatment ; Heparin-induced thrombocytopenia ; HIT antibodies ; Children ; Catheter patency
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The immunological form of heparin-induced thrombocytopenia (HIT) is a potentially life-threatening adverse reaction of heparin medication. It is mediated by multimolecular complexes consisting of platelet factor 4 (PF4)-heparin-IgG which bind to platelets via platelet Fcγ receptors. Cross-linking of multiple Fcγ receptors results in platelet activation, platelet aggregation and enhanced thrombin generation with a increasing risk of developing new thrombosis. In children, data on HIT are sparse. This review of the literature reports on 8 children aged 3 months to 15 years and 14 newborns suffering from HIT. Additionally, we report one new case treated with danaparoid sodium. Thrombotic complications were venous (n = 12) and arterial (n = 15). The children received heparin either for a spontaneous thrombotic event, for severe cardiac diseases or to maintain patency of intravascular catheters which are used for nutrition, blood sampling, and for application of medication. After diagnosis of HIT they were further anticoagulated with aspirin, warfarin, danaparoid sodium, lepirudin or low molecular weight heparin. Conclusion Although HIT is less frequently reported in newborns and children, paediatricians should be aware of HIT in childhood as a potential complication of heparin application. The widespread practice of flushing catheters with heparin should also be debated in view of the risk of triggering the primary immune-response of HIT. In 1999, treatment options for further parenteral anticoagulation of HIT patients are danaparoid sodium (a low-molecular weight heparinoid) and lepirudin (a direct thrombin inhibitor).
    Materialart: Digitale Medien
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  • 113
    ISSN: 1432-1076
    Schlagwort(e): Key words Factor V G1691A ; Prothrombin G20210A ; Lipoprotein (a) ; Central venous lines ; Children
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract To evaluate the role of inherited thrombophilia in the development of central venous line (CVL)-related thrombosis, the following parameters were determined in 77 pediatric-oncologic patients with CVL: activated protein C (APC)-ratio, factor V (FV) G1691A and prothrombin G20210A mutation, protein C, protein S, antithrombin, coagulation factor XII, lipoprotein (a) and homocysteine. An inherited prothrombotic risk factor was found in 17 patients (23%). Four out of 14 patients with a single defect (hyperlipoproteinemia, heterozygous FV G1691A and prothrombin G20210A mutation, protein C deficiency type I) and all three patients with combined defects (heterozygous FV G1691A mutation combined with heterozygous prothrombin G20210A variant, protein S deficiency or hyperlipoproteinemia) suffered from CVL-related thrombosis. In 11 out of 77 patients (14%) a CVL-related thrombosis was detected. In 2 children thrombosis occurred a few days after asparaginase therapy and in another three thrombosis was associated with CVL-related septicemia caused by Staphylococcus epidermidis. After removal of CVL, thrombosis was detected in 5 children, in 2 without clinical symptoms but in the presence of inherited prothrombotic risk factors. Conclusion The present study demonstrates the clinical importance of CVL in combination with inherited thrombophilia in the development of thrombosis in pediatric-oncologic patients. Before or shortly after insertion of CVL, patients should be tested for the presence of factor V G1691A mutation, prothrombin G20210A variant and increased lipoprotein (a) values.
    Materialart: Digitale Medien
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  • 114
    ISSN: 1432-1084
    Schlagwort(e): Key words: Optic nerves ; Neuritis ; Children ; Central nervous system ; MR imaging
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. A 4-year-old boy developed bilateral optic neuritis. Although precise neuro-ophthalmological evaluation was difficult, the diagnosis was made with gadolinium-enhanced MR imaging using fat-suppression technique in the initial stage of the disease. Enhancement and enlargement of the intraorbital and intracanalicular optic nerve were demonstrated bilaterally as well as protrusion of the optic nerve head. The disease responded dramatically to intravenous steroid therapy. The etiologies in children usually differ from those in adolescent and adult patients.
    Materialart: Digitale Medien
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  • 115
    ISSN: 1432-1106
    Schlagwort(e): Key words Learning and memory ; Electrical stimulation ; Parafascicular thalamic nucleus ; Two-way active avoidance ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  To evaluate whether electrical stimulation of the parafascicular nucleus (PF) can improve short-term (24 h) and/or long-term (21 days) retention of two-way active avoidance, rats were implanted with an electrode at this nucleus (experimental groups) or above it (control groups). After a single 30-trial acquisition session, experimental groups were submitted to a 10-min session of electrical stimulation. Results showed that the simple implantation of an electrode at the posterior PF enhanced by itself the acquisition of two-way active avoidance, in such a way that the subsequent stimulation of this region may have been unable to further improve the performance of the rats. On the other hand, parafascicular stimulation improved the 24-h retention of the task in a site-specific way, since this effect was mainly seen after stimulation of the central PF region. The facilitative effect on 24-h retention could also depend on the level of performance achieved during the acquisition session, because this improvement was only evidenced in poorly learning animals. No effects were found on 21-day retention. The present results confirm the involvement of the PF in learning and memory and the functional heterogeneity of this nucleus.
    Materialart: Digitale Medien
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  • 116
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 125 (1999), S. 163-170 
    ISSN: 1432-1106
    Schlagwort(e): Key words Focal cerebral ischemia ; Photothrombosis ; Reperfusion ; Spontaneous recanalization ; Cerebral blood flow ; Edema ; Penumbra ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  In clinical thromboembolic stroke, spontaneous late recanalization is a common feature, but one which has been very sparsely studied experimentally. This study aimed at enabling the study of spontaneous reperfusion and exploring its consequences by modifying a recently developed photothrombotic-stroke model that focuses on the region-at-risk located within an ischemic ring-locus. The exposed crania of male Wistar rats (280–340 g) were subjected to a ring-shaped (5.0 mm outer diameter and 0.35 mm thick) laser-irradiation beam (514.5 nm; 0.89 W/cm2) for 2 min simultaneously with intravenous erythrosin B (17 mg/kg) infusion for 30 s. Transcardial carbon-black perfusion experiments revealed a ring-shaped cortical perfusion deficit at 4 h post-irradiation, which progressively increased at 10, 24, and 48 h, at which time the whole region-at-risk was pale with single distal branches of the middle cerebral artery being extensively narrowed, but not occluded. At 72 h, spontaneous reperfusion was observed in the region-at risk, which was even more pronounced at 7 and 28 days. Cortical cerebral blood flow (cCBF), measured by laser-Doppler flowmetry, was distinctly reduced at 2 min post-irradiation and further decreased slightly during 4 h of recording to ca. 24% of baseline values at the ring locus and 40% in the region-at-risk. In the region-at-risk, cCBF flow values were 23–30% of the baseline at 24–48 h post-irradiation, followed by a relative cCBF increase to 71 and 77% at 72 and 96 h post-irradiation. Brain water content in the ischemic part of the cortex increased steadily from 4 to 48 h post-irradiation; at 72 h, it leveled off and returned to control values at 7 days. In conclusion, by employing a laser beam in the shape of a thin ring, critically sustained cCBF reduction was followed by late, consistent spontaneous reperfusion in the region-at-risk in this novel photochemically induced stroke-in-evolution model.
    Materialart: Digitale Medien
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  • 117
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 125 (1999), S. 239-247 
    ISSN: 1432-1106
    Schlagwort(e): Key words Precision grip ; Motor development ; Motor control ; Children ; Object manipulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Recent evidence has shown that the anticipatory control of grip and load force is not innate and develops over several years in childhood. The present study examined the development of grasping behavior by quantifying the relationship between grip force and the vertical acceleration of an object. Children and adults were requested to use a precision grip to lift an instrumented object which varied in size and weight. Grip force, grip force rate and the vertical position and acceleration profiles of the test object were measured or calculated. The results demonstrated the presence of distinct developmental milestones in the maturation of precision grip from 2 to 9 years of age. With 2-year-old children, the peak acceleration was negatively correlated (r=–0.51, n=34, P〈0.01) with peak grip force during lifting. By 3 years of age, peak acceleration and peak grip force during lifting became positively correlated (r=0.28, n=104, P〈0.01) and the correlation continued to strengthen up to 9 years of age. Variations in the temporal coupling of both peak grip force and peak acceleration also decreased with maturation. Furthermore, starting at 4-years-old, children clearly controlled the acceleration and deceleration of the object in a symmetrical pattern and used a single burst of grip force rate to grasp the object with some regularity, suggesting that the emergence of an anticipatory control strategy had already begun.
    Materialart: Digitale Medien
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  • 118
    Digitale Medien
    Digitale Medien
    Springer
    European spine journal 8 (1999), S. 439-443 
    ISSN: 1432-0932
    Schlagwort(e): Key words Low back pain ; Children ; Clinical examination ; Questionnaire ; Prevalence
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A study was undertaken to analyse the prevalence of low back pain (LBP) and confounding factors in primary school children in the city of Antwerp. A total of 392 children aged 9 were included in the study. All children completed a validated three-page questionnaire and they all underwent a specific lumbar spine oriented medical examination during their annual routine medical school control. This examination was performed by the city school doctors. The questionnaire was composed of easy “yes/no” questions and visual analogue scales. Statistical analysis was performed using Student’s t-test and chi-squared test at the significance level P 〈 0.05. The prevalence of LBP was high. No gender difference was found. A total of 142 children (36%) reported having suffered at least one episode of LBP in their lives. Of these, 33 (23%) had sought medical help for LBP from a doctor or physiotherapist. Sixty-four percent of children reporting LBP said that at least one of their parents suffered from or complained of LBP. This was significantly higher than for the children who did not report having suffered LBP. The way in which the school satchel was carried (in the hand, on the back) had no bearing on the incidence of LBP. There was significantly more LBP in children who reported playing video games for more than 2 h per day, but this was not so for television watchers. The visual analogue scales concerning general well-being were all very significantly correlated with self-reported LBP, with children who reported LBP being more tired, less happy, and worse sleepers. Of the 19 clinical parameters taken down during the medical examination, only one was significantly more prevalent in the group of children reporting LBP: pain on palpation at the insertion site on the iliac crest of the ilio-lumbar ligament. From this study we can establish that there are few clinical signs that can help to single out school children with LBP.
    Materialart: Digitale Medien
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  • 119
    ISSN: 1432-0851
    Schlagwort(e): Key words Transgenic ; Rat ; EGP-2 ; GA733-2 ; Immunotherapy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The human pancarcinoma-associated epithelial glycoprotein-2 (EGP-2), also known as 17-1A or Ep-CAM, is a 38-kDa transmembrane antigen, commonly used for targeted immunotherapy of carcinomas. Although strongly expressed by most carcinomas, EGP-2 is also expressed in most simple epithelia. To evaluate treatment-associated effects and side-effects on tumor and normal tissue respectively, we generated an EGP-2-expressing transgenic Wistar rat. To express the cDNA of the EGP-2 in an epithelium-specific manner, the 5′ and 3′ distal flanking regions of the human keratin 18 (K18) gene were used. EGP-2 protein expression was observed in the liver and pancreas, whereas EGP-2 mRNA could also be detected in lung, intestine, stomach and kidney tissues. In this rat, EGP-2-positive tumors can be induced by injecting a rat-derived carcinoma cell line transfected with the GA733-2 cDNA encoding EGP-2. Transgenic rats were used to study specific in vivo localization of an i.v. anti-EGP-2 monoclonal antibody, MOC31, applied i.v. Immunohistochemical analyses showed the specific localization of MOC31 in s.c. induced EGP-2-positive tumors, as well as in the liver. In contrast, in EGP-2-transgenic rats, MOC31 did not bind to EGP-2-negative tumors, the pancreas, or other normal tissues in vivo. In conclusion, an EGP-2-transgenic rat model has been generated that serves as a model to evaluate the efficacy and safety of a variety of anti-EGP-2-based immunotherapeutic modalities.
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  • 120
    ISSN: 1432-0738
    Schlagwort(e): Key words Benzene ; Benzene metabolites ; Diabetes ; Cytochrome P-450 ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Benzene is a ubiquitous environmental pollutant primarily metabolized by a cytochrome P-450 (CYP-450) isoenzyme, CYP-450 IIE1. A consistent induction of CYP450 IIE1 has been observed in both rat and human affected by diabetes mellitus. The aim of this study was to evaluate whether streptozotocin (STZ)-induced diabetes determines modifications in the metabolic pathways of benzene in rat. Benzene (100 mg/kg per day, dissolved in corn oil) was administered i.p. once a day for 5 days. Urine samples were collected every day in STZ-treated and normoglycaemic animals, treated and untreated with benzene (n = 10). Urinary levels of trans,trans-muconic acid and of phenol, catechol and hydroquinone (free and conjugated with sulphuryl and glucuronic group) were measured by high-performance liquid chromatography (HPLC). In normoglycaemic rats during the 5 days of treatment with benzene we observed a progressive and significant decrement in the urinary excretion of phenol, phenyl sulphate and glucuronide, catechol, catechol glucuronide, hydroquinone, hydroquinone glucuronide and t,t-muconic acid (P 〈 0.05). In the diabetic animals, conversely, the same metabolites showed progressively increasing urinary levels (P 〈 0.05). Catechol sulphate and hydroquinone sulphate levels were below the instrument's detection limit. In the comparison between diabetic and normoglycaemic benzene treated rats, the inter-group difference was significant (P 〈 0.05) from day 3 of treatment for t,t-muconic acid, and from day 1 for free and conjugated phenol, free and glucuronide catechol and free hydroquinone. In the normoglycaemic rat exposed to benzene the decreasing trend observed in urinary excretion of free and conjugated metabolites may be due to their capability to reduce cytochromial activity. Conversely, in the diabetic rat, urinary levels of benzene metabolites tended to increase progressively, probably due to the consistent induction of CYP-450 IIE1 observed in diabetes, which would overwhelm the inhibition of this isoenzyme caused by phenolic metabolites. Furthermore, the metabolic switch towards detoxification metabolites observed after administration of high doses of benzene is not allowed in the diabetic because of reduced glutathione-S-transferase activity. As a consequence, higher levels of hydroquinone, phenol and catechol, considered the actual metabolites responsibles for benzene toxicity, will accumulate in the diabetic rat. Extrapolating these data to human, we may thus suggest that occupational exposure to benzene of a diabetic subject poses a higher risk level, as his metabolism tends to produce and accumulate higher levels of reactive benzene catabolites.
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  • 121
    ISSN: 1432-1173
    Schlagwort(e): Schlüsselwörter Kinderdermatologie ; Exanthem ; Kinder ; Key words Pediatric dermatology ; Exanthema ; Children
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Unilateral laterothoracic exanthem a (ULE) is a self-limited, probably infectious-allergic skin disease predominately affecting small children. We describe five such cases. The typical unilaterally located or at least unilaterally dominant exanthem usually starts in the axillary region and is characterized by red, partly confluent papules and fine scales. Two of the children presented with atypical manifestations of ULE. Due to its asymptomatic course, therapy is not necessary in the majority of cases.
    Notizen: Zusammenfassung 5 Kinder mit der Diagnose eines unilateralen laterothorakalen Exanthems (ULE) werden vorgestellt. Beim ULE handelt es sich um eine selbstlimitierende, vermutlich infektallergische Hauterkrankung, die hauptsächlich im Kleinkindesalter auftritt. Das typischerweise streng einseitig lokalisierte, immer jedoch einseitig dominierende Exanthem geht meist von der Axillarregion aus und zeigt erythematöse, teils konfluierende Papeln. Zwei der fünf Kinder zeigten auch atypische Hautveränderungen eines ULE. Eine Behandlung ist aufgrund seines überwiegend asymptomatischen Verlaufs in der Mehrzahl der Fälle nicht notwendig.
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  • 122
    Digitale Medien
    Digitale Medien
    Springer
    Child's nervous system 15 (1999), S. 563-570 
    ISSN: 1433-0350
    Schlagwort(e): Key words Ependymoma ; Children ; Chemotherapy ; Phase II
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Chemotherapy has been used extensively in the management of children with intracranial ependymoma. In this review, we discuss the results of phase II studies and clinical trials conducted in newly diagnosed and recurrent ependymomas. There is little evidence that chemotherapy is effective in this tumour. The response rate to single agents is 11%, with less than 5% complete responses, cisplatin being the most active agent in phase II studies. Combinations may be more effective, although the response rate with high-dose regimens is disappointing. Early results of protocols conducted in infants and young children do not suggest that chemotherapy is beneficial. A more rigorous assessment of chemotherapy is required in order to define its role in patients with intracranial ependymomas. Indeed, it is difficult to justify the use of chemotherapy outside such studies. More large studies, perhaps intergroup, limited to children with ependymomas would be of particular value.
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  • 123
    Digitale Medien
    Digitale Medien
    Springer
    Child's nervous system 15 (1999), S. 342-346 
    ISSN: 1433-0350
    Schlagwort(e): Key words Severe neurological disabilities ; Managed and rationed care ; Children ; Questionnaire survey ; Pediatric neurosurgeons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The attitudes of pediatric neurosurgeons to managed and rationed care for children with severe neurological disabilities were surveyed as reflected in responses from International Society for Pediatric Neurosurgery (ISPN) members to a questionnaire. Of 399 ISPN members, 156 (39.1%) responded to the questionnaire. There were 15 questions, which were designed to explore what care is medically indicated, whether all medically indicated care should always be provided, and how this care should be managed or rationed. Most respondents agreed that these patients should receive the same level of medical care as a normally developing child. However, respondents felt that cardiopulmonary resuscitation (CPR) is not indicated if a child is not retrievable. Most respondents also felt that provision of care should be influenced by cost. The responses to the questions from ISPN members were compared with those from Child Neurology Society (CNS) members.
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  • 124
    Digitale Medien
    Digitale Medien
    Springer
    Child's nervous system 15 (1999), S. 468-471 
    ISSN: 1433-0350
    Schlagwort(e): Key words Seizures ; Epilepsy ; Children ; EEG ; Computed tomography (CT) ; Saudi Arabia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The clinical patterns, including history, examination, and electroencephalographic (EEG) and computed tomography (CT) findings were examined prospectively in 263 children (153 boys, 110 girls) with newly diagnosed recurrent seizures. The overall mean age was 4.2 years, with a range of 0.05–13 years. The age of onset was within the first year of life in 128 (48.7%) of the patients. Hypoxic-ischemic encephalopathy (14.8%), febrile seizures (9.1%) and developmental delay (4.6%) were the predominant signs in this age group. Consanguinity of the parents was present in 29.7% cases. The main EEG abnormalities were epileptiform activity, which was generalized in 133 (50.6%) and focal in 80 (30.4%). Other abnormalities included slow wave activity in 41 (15.6%) and hypsarrhythmia in 3 (1.1%). The main seizure types were generalized in 60.4% and partial in 32.7%. The types of epileptic syndromes included localization-related (28.1%), generalized (23.2%), undetermined (37.4%) and (special) syndromes 11.4%. The cranial CT findings were normal in 60.5%, and the predominant abnormality was cerebral atrophy in 25.3%. The pattern of seizure types and the peak presentation in early childhood are comparable to those in western reports.
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  • 125
    ISSN: 1433-0350
    Schlagwort(e): Key words Cerebrospinal fluid shunt ; Infection ; Colonization ; Children
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract To evaluate the efficiency of our management protocol, 33 pediatric cases of bacteria-infected cerebrospinal fluid shunt were reviewed. The causative organism was staphylococcus in 23 patients. In 23 patients, shunt infection was managed according to the protocol. The complexity of the shunt system did not prolong hospitalization. Unchanged but externalized tubings showed persistent colonization despite adequate antibiotics in 10 of 21 patients. Staphylococcal infection was oxacillin-resistant in 7 of 19. The efficiency of an `off-antibiotics' trial was minimal. Further modification of the protocol is expected to enhance efficiency of the management.
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  • 126
    ISSN: 1433-0350
    Schlagwort(e): Key words Hydrocephalus model ; Kaolin ; Micro-balloon ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We used three types of specialized micro-balloons 0.7–1.35 mm in outer diameter instead of kaolin to develop a reproducible rat model of hydrocephalus with a low experimental mortality. The micro-balloon was inserted 6 mm deep into the cisterna magna via a burr hole immediately behind the lambda. The angle of introduction was 50°. We also set up kaolin-induced hydrocephalic models in 25 rats as controls. The kaolin model revealed 52% mortality with an 80% induction rate of hydrocephalus, while the balloon model showed 9% mortality with a 60% induction rate. Balloon-induced hydrocephalus was maximal at 1 week and tended to decrease after 2–3 weeks. The pathological findings were not different between the two models. We concluded that the micro-balloon model for hydrocephalus is an easily reproducible model with low experimental mortality.
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  • 127
    Digitale Medien
    Digitale Medien
    Springer
    Child's nervous system 15 (1999), S. 695-710 
    ISSN: 1433-0350
    Schlagwort(e): Key words Craniosynostosis ; Blood salvage ; Blood conservation ; Allogeneic blood transfusion ; Children ; History
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  In the history of surgery, every single step forward in the development of complex surgical techniques has been sustained by the acquisition of more reliable and effective methods for controlling hemostasis. For many years, in fact, uncontrolled hemorrhages, together with infections, represented the most deadly hazard of surgical procedures. In the last century, technical advances in surgical hardware and homologous blood transfusions have been utilized to counteract operative and postoperative anemia and hypovolemia. At the end of this millennium, however, new revelations about the infective and noninfective risks of allogeneic blood transfusions have led to a new acceleration in patients’ and physicians’ demands for autologous transfusions and more efficient blood conservation techniques. Specific surgical protocols, based on the preoperative administration of r-HuEPO, preoperative autologous blood donation, acute preoperative normovolemic hemodilution and intraoperative blood salvage techniques, have been designed by pediatric neurosurgeons to minimize the exposure of patients affected by craniosynostoses to allogeneic blood and blood components even when the surgical procedure is to be realized at an early age. In spite of the evolution expected in this area in the immediate future, the implementation of these blood concentration methodologies may prove to be highly effective only when associated with a concerned attitude of the surgeon toward blood-sparing intraoperative strategies.
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  • 128
    ISSN: 1433-0350
    Schlagwort(e): Key words Head injury ; Children ; Traumatic intracerebral haematoma ; Coma scale
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In contrast to the case of extracerebral haematomas, the criteria for operative treatment of traumatic intracerebral haematoma (TIH) are not clear. The purpose of this study was to find factors that would be helpful in reaching a decision for surgical or conservative treatment of TIH. We performed a retrospective analysis of 31 consecutive cases of TIH treated in our department. The following factors were estimated: age, mechanism of injury, initial GCS or CCS score, neurological deficits, coexistence of arterial hypotension and respiratory disturbances, and localisation and size of the haematoma. The outcome was evaluated according to a modified GOS. Treatment was surgical for 20 patients and conservative for 11. Patients with GCS or CCS scores of 3–8 were treated surgically significantly more often than those with higher scores. The other factors did not correlate with type of treatment. It seems, then, that the clinical status of the patient, especially the level of consciousness according to the GCS or CCS score, is the most important predictor of the need for surgery in children with TIH.
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  • 129
    ISSN: 1432-2072
    Schlagwort(e): Key words Anhedonia ; Amphetamine ; Depression ; Progressive ratio ; Psychostimulant ; Rat ; Sucrose solution ; Withdrawal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Numerous studies have shown that withdrawal from sustained high doses of psychostimulant drugs such as cocaine or d-amphetamine produces depressive-like symptoms in both rats and humans. The majority of experiments with rodents have assessed the effects of amphetamine withdrawal on reinforcing electrical self-stimulation in different brain regions, but relatively few have examined effects on responding for natural reinforcers. In the present study, two groups of mildly food and water deprived male rats were trained to respond on a lever for a 4% sucrose solution under a progressive ratio schedule of reinforcement. One group was subsequently administered a 4-day regimen of injections of increasing doses of d-amphetamine based on a schedule shown previously to reduce self-stimulation behaviour. Break points were significantly reduced for up to 4 days after the termination of drug administration, suggesting a decreased motivation to obtain the natural reward. A further experiment demonstrated that the identical drug regimen produced no effect upon consumption of the 4% sucrose solution when it was freely available. These results demonstrate that the progressive ratio procedure may be a useful technique for evaluating changes in motivation for natural reinforcing stimuli following withdrawal from psychostimulant drugs.
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  • 130
    ISSN: 1432-2072
    Schlagwort(e): Key words Methamphetamine ; Dopamine ; Serotonin ; Phentermine ; Fenfluramine ; Drug-discrimination ; Self-administration ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  To analyze the involvement of dopamine (DA) and serotonin (5-HT) release in the stimulus properties of methamphetamine, two amphetamine analogs that selectively release either brain DA (phentermine) or 5-HT (fenfluramine) were tested for their ability to substitute for methamphetamine in rats discriminating methamphetamine (1.0 mg/kg) from saline. They were subsequently tested for their ability to alter IV methamphetamine (0.06 mg/kg per injection) self-administration in the same species when given as a pretreatment. The DA releaser phentermine, like methamphetamine itself, decreased methamphetamine self-administration (to 70% of baseline responding), but only at a dose of 3.0 mg/kg that fully generalized to the methamphetamine stimulus in the discrimination study. The 5-HT releaser fenfluramine attenuated methamphetamine self-administration to a much larger extent than phentermine (to 37% of baseline responding) at a dose of 1.8 mg/kg that did not generalize to methamphetamine and did not decrease rate of responding in the discrimination study. Tolerance developed to the inhibitory effect of 1.8 mg/kg fenfluramine on methamphetamine self-administration when it was given repeatedly over four consecutive daily sessions. The fenfluramine-induced decrease in methamphetamine self-administration was also attenuated when it was given together with the small 1.0 mg/kg dose of phentermine. These results suggest that DA release plays a dominant role in the discriminative stimulus effects of methamphetamine. However, stimulation of 5-HT release can strongly modify methamphetamine self-administration.
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  • 131
    ISSN: 1432-2072
    Schlagwort(e): Key words 7-OH-DPAT ; d-Amphetamine ; Dopamine ; Extinction ; Haloperidol ; Progressive-ratio ; Rat ; Self-stimulation ; Ventral tegmental area
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Progressive-ratio (PR) schedules, which have been widely used to study the reinforcing efficacy of various reinforcers (in particular IV psychostimulants), have been very seldom applied to the study of positively reinforcing electrical brain stimulation (EBS). In the present study, rats were required to emit a progressively increasing number of lever-presses (3,4,6,7,9,11,14,16, etc.) for access to successive reinforcers (periods of VTA self-stimulation). Each period of self-stimulation consisted of ten trains of square pulses of EBS; each train was available under a continuous reinforcement schedule. The number of periods of EBS earned during a session was deemed the breaking point (BP). After acquisition and stabilization of self-stimulation, a study was carried out to verify that changes in the strength of the EBS (i.e. changes in the frequency, the intensity or the pulse duration, one parameter at a time) induced changes in the BP. The effects of IP pretreatments with d-amphetamine, the dopamine D3/D2 receptor agonist 7-OH-DPAT and haloperidol were then assessed. Decreases in the strength of EBS decreased the BP. However, increasing the strength above training values resulted in minimal increases in the BP. d-Amphetamine (0.25–1 mg/kg) dose-dependently increased the BP; additionally, when the reinforcer was withheld (i.e. in conditions of extinction, with the stimulator turned off) d-amphetamine was also found to augment the BP. This might indicate that d-amphetamine preferentially potentiated the motivational (non-rewarded presses) aspects of VTA self-stimulation under this type of PR schedule. 7-OH-DPAT had biphasic effects: at low doses (0.01 and 0.03 mg/kg), it tended to decrease the BP while higher doses (1 and 3 mg/kg) robustly increased the BP. Under conditions of extinction, 7-OH-DPAT (1 mg/kg) had a tendency to increase the BP, but this effect was not statistically significant and did not approach the magnitude of effects observed with d-amphetamine. Haloperidol (0.08–0.48 mg/kg IP) dose-dependently reduced the BP, suggestive of a decrease in the reinforcing efficacy of the EBS. These results show that rats can be trained to self-administer EBS of the VTA under a PR schedule of reinforcement and that this behaviour is sensitive to disruption or potentiation of dopaminergic neurotransmission.
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  • 132
    ISSN: 1432-2072
    Schlagwort(e): Key words Deramciclane ; Ritanserin ; Chlordiazepoxide ; Slow wave sleep ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The influence of serotonergic and benzodiazepine type anxiolytic drugs on the cortical activation and sleep-wakefulness cycle were compared by evaluating the effects of ritanserin and deramciclane (EGIS-3886), two 5-HT2 receptor antagonists, and chlordiazepoxide on the electroencephalogram (EEG) in freely moving rats. Following drug administration (1, 3, and 10 mg/kg, PO for all drugs), EEG was continuously sampled for 6 h and power spectra were calculated for every 5 s to assess changes in slow wave activity and sleep phases. In a separate test, anticonvulsant effects of the drugs were examined in mice. Both deramciclane and ritanserin slightly increased total time spent in deep sleep (DS) and lengthened sleep episodes. In contrast, chlordiazepoxide had a strong inhibitory action on DS, sleep time being shifted to more superficial light sleep (LS). The incidence and length of the high voltage spindle (HVS) episodes characteristic for the motionless, awake rat were increased at the highest dose of both deramciclane and ritanserin, while it was decreased by chlordiazepoxide. In mice, chlordiazepoxide had a marked anticonvulsant effect, while deramciclane was moderately effective and ritanserin ineffective. In conclusion, the 5-HT2 receptor antagonist anxiolytic drugs seem to be superior compared to the benzodiazepine type anxiolytic drug, chlordiazepoxide, as ritanserin and deramciclane improved sleep quality by increasing sleep episode length and time spent in DS, while chlordiazepoxide enhanced sleep fragmentation and decreased DS.
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  • 133
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 142 (1999), S. 327-333 
    ISSN: 1432-2072
    Schlagwort(e): Key words Caffeine ; Nicotine self-administration ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The prevalence of tobacco smoking and coffee drinking place nicotine and caffeine among the most used licit drugs in many societies and their consumption is often characterised by concurrent use. The pharmacological basis for any putative interaction between these drugs remains unclear. Epidemiological reports support anecdotal evidence, which suggests that smokers consume caffeine to enhance the euphoric effects of nicotine. The aim of the present experiment was to examine effects of chronic exposure to caffeine on responding maintained by nicotine. Sprague-Dawley rats consuming caffeine (approximately 150–180 mg/kg per day) in their drinking water for 7 days prior to the beginning and throughout behavioural testing acquired intravenous nicotine self-administration (0.03 mg/kg per infusion) more rapidly than did controls. In a cross-over design, exclusion of caffeine brought levels of nicotine self-administration back to baseline, while adding caffeine to the drinking water of control rats increased responding maintained by nicotine over 90%. These findings strongly suggest that caffeine can potentiate the reinforcing properties of nicotine, thus highlighting the importance of environmental factors in shaping and maintaining tobacco smoking.
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  • 134
    ISSN: 1432-2072
    Schlagwort(e): Key words Continuous cocaine ; Tolerance ; 5-HT3 receptor ; DA release ; Nucleus accumbens ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We have previously reported that continuous cocaine administration functionally down regulates 5-HT3 receptors in the nucleus accumbens. The current experiments evaluated the duration of behavioral tolerance to cocaine and whether the duration of behavioral tolerance and 5-HT3 receptor down-regulation co-varied. Rats were withdrawn from a pretreatment regimen (40 mg/kg/per day cocaine or 0.9% saline for 14 days) for 1, 7 or 14 days. The rats were either sacrificed, and slices from the nucleus accumbens obtained, or were exposed to behavioral rating procedures. The results indicated that continuous cocaine administration significantly attenuated the ability of mCPBG to facilitate K+-stimulated DA release on days 1 and 7, but not day 14, of withdrawal. Furthermore, continuous cocaine administration induced behavioral tolerance to a cocaine challenge on days 1 and 7, but not day 14, of withdrawal. These results suggest that continuous cocaine administration functionally down-regulates 5-HT3 receptors in the nucleus accumbens, and this functional down-regulation co-varies with the behavioral tolerance induced by continuous cocaine administration. Hence, a functional down-regulation of accumbens 5-HT3 receptors may represent a partial mechanism for the tolerance following continuous cocaine administration.
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  • 135
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 142 (1999), S. 369-374 
    ISSN: 1432-2072
    Schlagwort(e): Key words Clozapine ; Withdrawal ; Dependence ; Temperature ; Atypical antipsychotic ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Rationale: In schizophrenics, clozapine has been reported to induce various withdrawal signs and rapid onset relapse to psychosis on cessation of chronic treatment. Objective: The study was designed to develop an animal model of one aspect of clozapine tolerance and withdrawal using core body temperature measures. Methods: Two groups of 15 female Wistar rats were treated chronically (b.i.d.) with clozapine at 6 or 12 mg/kg per injection for 21 days prior to cessation of drug treatment, withdrawal being studied over 4 consecutive days. Body temperatures were assessed daily throughout the study. Results: Acutely, clozapine induced dose-related hypothermia, to which complete tolerance developed in both groups, the development of tolerance being more rapid in the group treated with 6 mg/kg per injection of clozapine. During withdrawal only the group treated chronically with 12 mg/kg per injection of clozapine showed rapid onset significant hyperthermia. This dissipated progressively over days, and was completely absent after 4 days of withdrawal. Conclusions: Clozapine induced a clear somatic withdrawal sign after chronic treatment. It is suggested that, in future research in both humans and animals, it is important to attempt to differentiate between clozapine withdrawal and clozapine withdrawal-induced relapse to psychosis. It is also important to characterise the clozapine withdrawal syndrome fully in animals; to establish the neurochemical mechanisms involved in such withdrawal; and to determine which novel antipsychotics are most efficacious in inducing clozapine-like withdrawal effects, in suppressing clozapine withdrawal, and in preventing relapse to psychosis in patients being transferred from clozapine to novel atypical antipsychotic drugs.
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  • 136
    ISSN: 1432-2072
    Schlagwort(e): Key words Ethanol ; Limited access ; Nicotine ; Mecamylamine HCl ; Rat ; Voluntary intake
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Observations in humans suggest that the initial use of tobacco occurs in close temporal proximity to experimentation with alcohol. There have been relatively few research reports, however, examining possible interactions between these two agents. The present experiments examined the effect of nicotine exposure on the acquisition of ethanol drinking behavior in a limited access procedure. In experiment 1, rats were presented with 1-h access to ethanol solutions of increasing concentration for a period of 20 days. Subcutaneous injections of nicotine (0.6 or 1.2 mg/kg salt) or vehicle were administered 30 min prior to each ethanol presentation. Experiment 2 used a similar method, but rats were presented with water along with ethanol during the 1-h test session. Mecamylamine, a nicotinic receptor antagonist, was administered 30 min prior to the nicotine treatment. Nicotine was seen to produce a dose-dependent increase in ethanol drinking behavior which commenced at the 5% ethanol concentration and continued at 8% and again at 10%. In the second experiment, mecamylamine was observed to block completely the nicotine-induced increase in ethanol drinking behavior. The findings suggest that exposure to nicotine can facilitate the acquisition of ethanol drinking behavior in naive rats and that this effect is mediated by nicotine’s interaction at the nicotinic-cholinergic receptor.
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  • 137
    ISSN: 1432-2072
    Schlagwort(e): Key words Chlordiazepoxide ; FG 7142 ; Rat ; Diencephalic amnesia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The intralaminar thalamic nuclei (ILn) have been implicated as a critical site of pathology in amnesia. Lesions of the ILn have been found to produce behavioral effects comparable to benzodiazepine (BDZ) receptor agonists. We compared the effects of chlordiazepoxide (CDP), a BDZ agonist, and FG 7142, a partial inverse agonist at the BDZ receptor, in rats with thalamic lesions and in unlesioned controls. Delayed matching-to sample (DMS) performances were studied during treatment with ascending doses of CDP, counterbalanced trials with 2.5 mg/kg CDP and saline, ascending doses of FG 7142, and (for unlesioned controls only) counterbalanced trials with saline and higher doses of CDP. CDP had effects similar to the ILn lesion, decreasing response speed and percent correct responding in a delay-independent fashion. These effects were additive with the impairments associated with the ILn lesion. The effects of FG 7142 were more complex. At lower doses, it increased response speed without affecting response accuracy. At higher doses, it diminished both the speed and the accuracy of DMS responding. These results support the hypothesis that ILn lesions and BDZ agonists have similar effects on DMS performance. The biphasic effects observed for FG 7142 are consistent with other evidence that low doses of this drug enhance while higher doses impair memory performance. Although DMS accuracy was not improved, the enhancement observed for response speed provides evidence that partial inverse BDZ agonists have potential utility as treatments for cognitive impairments associated with amnesia.
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  • 138
    ISSN: 1432-2072
    Schlagwort(e): Key words Male sexual behavior ; Sexual impotence ; Plant extracts ; Turnera diffusa ; Pfaffia paniculata ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Sexually potent and sexually sluggish/impotent male rats were treated orally with different amounts of Turnera diffusa and Pfaffia paniculata fluid extracts (0.25, 0.50, 1.0 ml/kg). While having no effect on the copulatory behavior of sexually potent rats, both plant extracts – singly or in combination – improved the copulatory performance of sexually sluggish/impotent rats. The highest dose of either extract (1 ml/kg) (as well as the combination of 0.5 ml/kg of each extract) increased the percentage of rats achieving ejaculation and significantly reduced mount, intromission and ejaculation latencies, post-ejaculatory interval and intercopulatory interval. Neither extract affected locomotor activity. These results seem to support the folk reputation of Turnera diffusa and Pfaffia paniculata as sexual stimulants.
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  • 139
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 143 (1999), S. 209-214 
    ISSN: 1432-2072
    Schlagwort(e): Key words Baclofen ; Cocaine ; Extinction ; Intravenous self-administration ; Maintenance dose ; Rat ; Reinstatement of responding ; Relapse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract   Rationale: Recent studies suggest that the GABAB receptor agonist, baclofen, may be a useful pharmacotherapy for cocaine abuse. Objectives: To investigate further the effects of baclofen on maintenance and reinstatement of cocaine-reinforced behavior in rats. Methods: Two groups of rats were trained to self-administer IV cocaine (0.2 or 0.4 mg/kg per infusion) during daily 7-h sessions under a fixed-ratio 1 schedule. Rats were pretreated with baclofen (1.25, 2.5 or 5 mg/kg IP) or saline before the session for 5 consecutive days. An additional group of rats was trained to self-administer IV cocaine (0.4 mg/kg per infusion) during the first 2 h of daily 7-h sessions. Cocaine was replaced by saline for the remaining 5 h of the session. Once behavior had stabilized over the 7-h period, priming injections of saline (IV), cocaine (3.2 mg/kg IV) or baclofen (1.25 or 2.5 mg/kg IP) were administered prior to hour 4. Injections of baclofen (1.25 or 2.5 mg/kg IP) or saline were also given before priming injections of cocaine. Results: Pretreatment with the two higher doses of baclofen (2.5 and 5 mg/kg) decreased the number of cocaine infusions in both maintenance groups (0.2 and 0.4 mg/kg) over the 5-day treatment period. Baclofen had a greater suppressant effect on responding maintained by the lower dose of cocaine. Priming injections of baclofen (1.25 and 2.5 mg/kg) or saline did not reinstate responding. However, these same doses of baclofen dose-dependently reduced the reinstatement of responding produced by priming injections of cocaine. Conclusions: 1) The magnitude of the suppressant effects of baclofen on maintenance of cocaine self-administration depends upon the maintenance dose, 2) baclofen may be useful in preventing reinstatement of cocaine-seeking behavior, and 3) compared to maintenance, reinstatement of responding is more sensitive to the suppressant effects of baclofen.
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  • 140
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 143 (1999), S. 315-317 
    ISSN: 1432-2072
    Schlagwort(e): Key words SR141716 ; Hyperphagia ; Rat ; Pre-feed ; Eating ; Appetite
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract   Rationale: Central cannabinoid systems have been implicated in appetite regulation by the respective hyperphagic actions of exogenous cannabinoids, such as Δ9-THC, and hypophagic effects of selective cannabinoid receptor antagonists. Objective: This study examined whether an endogenous cannabinoid, anandamide, could induce overeating, via a specific action at central (CB1) cannabinoid receptors. Methods: Pre-satiated male rats (n=18), received subcutaneous injections of anandamide (0.5, 1.0, 5.0, 10.0 mg/kg) before 3-h, nocturnal food intake tests. In a second series of intake tests (n=8), anandamide injection (1.0 mg/kg) was preceded by injection of the specific CB1 receptor antagonist, SR141716 (0.1, 0.5, 1.0 mg/kg SC). Results: All doses of anandamide induced significant overeating, with 1.0 mg/kg being most potent. Additionally, hyperphagia induced by 1.0 mg/kg anandamide was dose-dependently attenuated by SR141716 pretreatment. Conclusion: This first demonstration of anandamide-induced, CB1-mediated, overeating provides important evidence for the involvement of a central cannabinoid system in the normal control of eating.
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  • 141
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 143 (1999), S. 318-321 
    ISSN: 1432-2072
    Schlagwort(e): Key words Nicotine ; Cotinine ; Self-administration ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract   Rationale: The route of nicotine administration between animal models and humans is very different and further investigation by determining levels of nicotine entering into the circulatory system is warranted. Objective: The present study addresses the validity of the rat self-administration procedure by comparing plasma levels of nicotine in the rat with levels reported in smokers following cigarette consumption. Methods: Plasma levels of nicotine and its metabolite cotinine were measured in 17 rats following intravenous self-administration of a range of nicotine doses (0.015, 0.03 and 0.06 mg/kg per infusion). Results: The two larger unit doses supported reliable self-administration behaviour with no overall difference in the patterns of nicotine intake. However, the total nicotine intake over the 2-h session was related to unit dose and this correlated highly with nicotine and cotinine levels measured in blood collected from the tail vein. On average, cotinine levels (50–200 ng/ml) were approximately 2-fold higher than nicotine levels (40–120 ng/ml) in plasma. Following an extinction test for one session in which saline was substituted for nicotine, no change in behaviour was observed in the two groups, while plasma levels of nicotine and cotinine dropped to nominal levels. Conclusions: The concentrations of nicotine attained following nicotine self-administration appear to be similar to levels reported in smokers after cigarette consumption, providing further validation of this procedure as an animal model of nicotine dependence.
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  • 142
    ISSN: 1432-2072
    Schlagwort(e): Key words MDMA (3 ; 4-methylenedioxymethamphetamine) ; Serotonin ; Psychopathology ; Human ; Rat ; Prepulse inhibition ; Habituation ; Schizophrenia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Rationale: Prepulse inhibition of acoustic startle refers to the reduction in the startle response when the startling stimulus is preceded by a weak prepulse stimulus. This phenomenon provides an operational measure of sensorimotor gating that has been found to be reduced in patients with schizophrenia and rats treated with serotonin agonists or serotonin releasers. Objective: In this study, we compared the effects of a serotonin releaser, MDMA, on prepulse inhibition in laboratory rats and healthy human volunteers. In particular, we investigated whether MDMA disrupts PPI in humans as observed in animal studies. Methods: Rats were tested after placebo and MDMA in a counterbalanced order at an interval of 1 week, with separate groups of rats being used for each dose of MDMA (1.7, 5.4 and 17.0 mg/kg). On each test day, rats were first tested after no injections and retested 2 h later, 10 min after a subcutaneous injection of placebo or MDMA. For the human study, a placebo-controlled within-subject design and double-blind procedures were used. Subjects were examined twice at a 2 to 4 week interval after either placebo or drug administration (order being counterbalanced). On each test day, subjects underwent baseline testing including psychological and PPI measures. Ninety minutes later, subjects received placebo or MDMA (1.7 mg/kg PO) and were retested after 75 min during the peak of behavioral effects of MDMA. Results: As expected, MDMA decreased prepulse inhibition in a dose-related fashion in rats. In contrast, a typical recreational dose of MDMA (1.7 mg/kg, orally) increased prepulse inhibition in subjects experiencing robust psychological effects. Conclusions: This surprising disparity between the effects of the drug in rats and humans may reflect a species-specific difference in the mechanism of action of MDMA or in the behavioral expression of a similar pharmacological effect, or both.
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  • 143
    Digitale Medien
    Digitale Medien
    Springer
    Der Radiologe 39 (1999), S. 467-471 
    ISSN: 1432-2102
    Schlagwort(e): Schlüsselwörter Fremdkörper ; Aspiration ; Diagnostik ; Kinder ; Atemwege ; Key words Foreign body ; Aspiration ; Diagnostic imaging ; Children ; Respiratory tract
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Aspiration of foreign bodies is a common cause of respiratory distress in children between the age of 6 months and 3 years. The diagnosis of radiopaque foreign bodies is easy when the whole respiratory tract is depicted. Nonopaque foreign bodies need a more differentiated diagnostic approach. The first step should be plain films in inspiration and expiration. The performance of additional chest radiographs, fluoroscopy and if need be CT or nuclear scans depends on the result of the plain films. The chest radiograph may reveal a variety of findings, the commonest of which is unilateral air trapping. Rarely, atelectasis, recurrent pneumonia at the same localisation and inspiratory obstruction are found. Combinations of the above-mentioned findings are possible. Moreover, the absence of positive radiological findings does not exclude the diagnosis of foreign body aspiration.
    Notizen: Zusammenfassung Die Fremdkörperaspiration stellt eine häufige Ursache für Atemnot und respiratorische Insuffizienz bei Säuglingen und Kleinkindern zwischen 6 Monaten und 3 Jahren dar. Röntgendichte Fremdkörper bereiten bei Abbildung des gesamten Respirationstraktes keine diagnostischen Schwierigkeiten. Nicht röntgendichte Fremdkörper erfordern ein differenzierteres Vorgehen, wobei der erste radiologische Schritt in einer konventionellen Thoraxaufnahme in In- und Exspiration bestehen sollte. Zusätzliche Aufnahmen, Durchleuchtungsuntersuchung und gegebenenfalls die Durchführung einer computertomographischen oder szintigraphischen Untersuchung hängen vom Ergebnis der Thoraxaufnahme ab. Häufigstes radiologisches Erscheinungsbild ist die einseitige exspiratorische Ventilstenose mit Überblähung des betroffenen Lungenabschnittes. Seltener finden sich Atelektasen, rezidivierende Pneumonien an identischer Lokalisation und inspiratorische Ventilstenosen. Kombinationsbilder sind möglich, selbst ein unauffälliges Untersuchungsergebnis kann eine Aspiration nicht ausschließen.
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  • 144
    Digitale Medien
    Digitale Medien
    Springer
    Knee surgery, sports traumatology, arthroscopy 7 (1999), S. 243-245 
    ISSN: 1433-7347
    Schlagwort(e): Key words Patella ; Fracture ; Children
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Sportwissenschaft
    Notizen: Abstract Fractures of the patella are relatively rare injuries for children. Fourteen patients with patellar fractures were reviewed. There were 12 boys and two girls with the age ranging between 9 and 15 years and an average of 11.4 years. Sleeve fractures were the most common type of patellar fractures observed (eight cases), followed by transverse fractures (four cases) and comminuted fractures (two cases). All the fractures were treated with open reduction and followed up for 2 to 20 years. Overall results were good in 13 patients, and flexion limitation of the knee was seen in one. Fractures of the patella in children are characterised by sleeve fractures. The prognosis of the patients treated with open reduction is generally good.
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  • 145
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 141 (1999), S. 189-196 
    ISSN: 1432-2072
    Schlagwort(e): Key words Acoustic startle response ; Prepulse inhibition ; Sensorimotor gating ; Schizophrenia ; Medial geniculate body ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Prepulse inhibition of acoustic startle is the normal reduction in startle response to an intense auditory stimulus when this stimulus is immediately preceded by a weaker prestimulus. Previous studies have shown that several neuroanatomical structures and pathways in the brain are involved in the modulation of prepulse inhibition. In the present study, the functional importance of the medial geniculate body (MG) in the modulation of prepulse inhibition was investigated. To this end, in vivo brain microdialysis probes were used to infuse drugs locally into the MG of awake, freely moving rats simultaneously with startle response and prepulse inhibition measurements in the same animals. Intrageniculate infusion of the sodium channel blocker, tetrodotoxin, significantly reduced prepulse inhibition without affecting baseline startle amplitude. A similar effect was obtained after intrageniculate infusion of the GABAB receptor agonist, baclofen. In addition, intrageniculate infusion of muscimol, an agonist at the GABAA receptor complex, reduced prepulse inhibition, although this effect was obtained at a higher concentration of the drug compared to that of baclofen. These studies suggest that the MG is involved in the modulation of prepulse inhibition and that auditory signals relayed via the MG may be subjected to inhibitory control at this level, involving GABA neurotransmission.
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  • 146
    ISSN: 1432-2072
    Schlagwort(e): Key words Neurosteroids ; GABAA receptor ; Sleep ; EEG spectral analysis ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Progesterone has been shown to exert benzodiazepine-like effects on sleep, which suggests that they are mediated by an agonistic modulation of GABAA receptor functioning. To assess the involvement of GABAA receptors, we investigated the sleep responses to one dose of the GABAA antagonist picrotoxin (1.5 mg/kg) and progesterone (90 mg/kg), administered IP to eight rats alone and in combination, during the first 4 post-injection hours. Compared with vehicle, picrotoxin significantly delayed the latency to non-rapid eye movement sleep (non-REMS) and thereby decreased all sleep states, but barely affected the EEG activity within non-REMS. Progesterone significantly shortened non-REMS latency, increased pre-REMS, depressed low-frequency EEG activity (≤8 Hz) and augmented EEG activity in the higher frequencies within non-REMS. Except for the changes in high-frequency EEG activity, picrotoxin attenuated all effects of progesterone. These findings support the notion that GABAA receptors play an important role in the sleep effects of progesterone.
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  • 147
    ISSN: 1432-2072
    Schlagwort(e): Key words Ethanol ; Self-administration ; Dopamine ; Acetylcholine ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In the present study, the reactivity of striatal dopamine and dopamine-sensitive neurons in superfused striatal slices of ethanol-experienced rats was compared to that of ethanol-naive rats, 3 weeks after oral ethanol self-administration. During the acquisition phase (17 days), rats were offered increasing concentrations of ethanol (from 2 to 10%, 24 h per day) on an alternate-day schedule in a free choice with water. Following 2 weeks of unrestricted 10% ethanol consumption, the highest and lowest drinkers (representing about 25% of the upper and lower extremes of the total population) were selected. Preliminary experiments revealed that both groups of rats displayed a profound increase in ethanol consumption and preference 3 weeks after cessation of ethanol self-administration (deprivation effect). This deprivation effect was associated with an increase in electrically evoked release of [3H]dopamine from superfused nucleus accumbens slices, whereas the evoked [3H]dopamine release from caudate putamen slices remained unchanged. In slices of the caudate putamen, but not in nucleus accumbens slices, postsynaptic dopamine D1 receptor-stimulated cyclic AMP production was also enhanced. In addition, prior ethanol consumption enhanced the electrically evoked release of [14C]acetylcholine release in both striatal regions. Interestingly, the magnitude of these long-term neuroadaptations correlated with the amount of daily ethanol consumption, i.e. neuronal hyperresponsiveness in the striatum was more profound in the high than in the low ethanol drinkers. These data show for the first time that unrestricted free-choice ethanol consumption in rats is associated with a long-term increase in dopaminergic and cholinergic neurotransmission in the nucleus accumbens and caudate putamen. These (and other) neuroadaptations may underlie the enhanced motivation to self-administer ethanol and the maintenance of ethanol consumption long after deprivation.
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  • 148
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 142 (1999), S. 95-101 
    ISSN: 1432-2072
    Schlagwort(e): Key words Oxytocin ; SSRIs ; Depression ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The nonapeptide oxytocin is released into systemic circulation in situations of psychosocial interaction, and has been shown to be involved in mechanisms of social bonding and social recognition in laboratory studies. In view of disturbances in psychosocial relationships being a triggering factor for depression and anxiety, it is interesting to note that experimental studies have shown oxytocin to possess antidepressant- and anxiolytic-like actions. Thus, in the present study we examined effects of the SSRI citalopram (20 mg/kg IP) on plasma oxytocin, acutely and upon repeated administration, in adult male Sprague-Dawley rats. Plasma oxytocin, and some functionally related peptides (CCK, gastrin, somatostatin and insulin), were measured by standard radioimmunoassay techniques. Acute citalopram administration produced a statistically significant increase in plasma oxytocin and CCK levels. Administration of citalopram for 14 days did not attenuate the oxytocin-releasing effect to a challenge dose of the SSRI zimeldine (20 mg/kg SC), whereas CCK levels were not increased after the subchronic citalopram treatment. Thus, the SSRI citalopram produces increased plasma oxytocin levels acutely, and there appears to be no or little tolerance to this effect upon repeated administration. There were no, or variable, effects on plasma levels of gastrin, somatostatin or insulin. It is suggested that oxytocin release is an important aspect of the pharmacological actions of SSRIs, and this could be an important contributory factor for the clinical profile of this group of antidepressants with particular efficacy in disorders of psychosocial origin.
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  • 149
    ISSN: 1432-2072
    Schlagwort(e): Key words Antinociception ; Butorphanol ; Relative efficacy ; Opioid ; Rat ; Stimulus intensity ; Tolerance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract   Rationale: A common treatment strategy for the management of severe pain involves the co-administration of multiple opioid analgesics. Due to the increasing popularity of this practice, it is becoming increasingly important to understand the interactions between clinically employed opioids under a wide range of conditions. Objective: The purpose of the present investigation was to examine the effects of opioid combinations following acute and chronic administration of the low-efficacy mu-opioid butorphanol, and to determine if the effects of these combinations are modulated by the intensity of the nociceptive stimulus. Methods: In a warm-water, tail-withdrawal procedure, rats were restrained and the latencies to remove their tails from 50°C (low temperature) and 55°C (high temperature) water were measured following both acute and chronic administration of butorphanol. Opioids possessing both high (etorphine, levorphanol, morphine) and low [dezocine, (–)-pentazocine, nalbuphine] relative efficacy at the mu receptor were examined. Results: Under acute conditions, etorphine, levorphanol, morphine and dezocine increased tail-withdrawal latencies at both low and high temperatures, whereas (–)-pentazocine, nalbuphine and butorphanol increased latencies only at the low temperature. A dose of 30 mg/kg butorphanol increased the effects produced by these opioids at the low temperature, but antagonized the effects of etorphine, levorphanol, morphine and dezocine at the high temperature. During chronic treatment with 30 mg/kg per day butorphanol, tolerance was conferred to the antinociceptive effects of all the opioids examined, with greater degrees of tolerance conferred to those opioids possessing low efficacy at the mu receptor. During butorphanol treatment, etorphine, levorphanol and morphine increased tail-withdrawal latencies at both water temperatures, dezocine increased latencies at only the low temperature, and (–)-pentazocine, nalbuphine and butorphanol failed to increase latencies at either temperature. A dose of 30 mg/kg butorphanol antagonized the antinociceptive effects of etorphine, levorphanol, morphine and dezocine during chronic treatment, and these effects were observed at both water temperatures. Conclusions: These findings indicate that the interactions between butorphanol and other mu opioids vary quantitatively between low and high stimulus intensities, and between acute and chronic conditions. In most instances, however, these interactions can be predicted from the effects of the drugs when administered alone.
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  • 150
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 143 (1999), S. 293-301 
    ISSN: 1432-2072
    Schlagwort(e): Key words Methamphetamine ; Drug discrimination ; Norepinephrine ; Desipramine ; Nisoxetine ; Isoproterenol ; Propranolol ; Methoxamine ; Prazosin ; Clonidine ; Yohimbine ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract   Rationale:Neurochemical and clinical studies indicate involvement of noradrenergic (NE) neurotransmitter system in the actions of methamphetamine. Objective:The present study investigated NE involvement in the discriminative-stimulus effects of methamphetamine. Methods:In Sprague-Dawley rats trained to discriminate 1.0 mg/kg methamphetamine, IP, from saline under a fixed-ratio schedule of food presentation, effects of various NE agonists, antagonists and uptake inhibitors were tested. Results: Desipramine (3.0–18.0 mg/kg) and nisoxetine (5.6–30.0 mg/kg), two selective NE-uptake inhibitors, did not significantly generalize to methamphetamine when administered alone, but 5.6 mg/kg desipramine and 10.0 mg/kg nisoxetine significantly shifted the methamphetamine dose-response curve to the left. The beta NE agonist, isoproterenol (0.56–3.0 mg/kg), and antagonist, propranolol (1.0–18.0 mg/kg), neither generalized to methamphetamine when given alone nor altered the discriminative-stimulus effects of methamphetamine when administered in combination. The alpha-1 NE agonist methoxamine (1.0–5.6 mg/kg) failed to generalize to the methamphetamine training stimulus. When given in combination with methamphetamine, the alpha-1 NE antagonist, prazosin (1.0 mg/kg), shifted the methamphetamine dose-response curve somewhat to the right and partially blocked the discriminative-stimulus effects of the 1.0 mg/kg training dose of methamphetamine, but these changes were not significant or dose-related, with further increases in prazosin dose (1.8–10.0 mg/kg) either producing similar or smaller changes. The alpha-2 NE agonist, clonidine, partially generalized to methamphetamine at doses of 0.1–0.18 mg/kg and increased drug-appropriate responding at lower doses of methamphetamine, but it partially blocked the discriminative-stimulus effects of higher 0.56–1.0 mg/kg doses of methamphetamine over the same dose range. The alpha-2 NE antagonist, yohimbine, also partially generalized to methamphetamine and blocked the discriminative-stimulus effects of the 1.0 mg/kg training dose of methamphetamine at doses of 5.6–10.0 mg/kg. A lower 3.0 mg/kg dose of yohimbine increased methamphetamine-appropriate responding when given together with low 0.1–0.3 mg/kg doses of methamphetamine. Conclusions:The present data suggest that the NE system plays a modulatory role in the discriminative-stimulus effects of methamphetamine. These effects appear to be mediated through NE uptake sites and alpha-2 receptors, with limited involvement of alpha-1 receptors and beta receptors.
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  • 151
    ISSN: 1432-2072
    Schlagwort(e): Key words Ethanol ; Serotonin ; Delayed reinforcement ; Self-control ; Impulsivity ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: Tolerance to delay of reinforcement has been proposed as an important facet of self-control in both animals and man. Poor self-control, leading to impulsive behaviour, can be a major problem if it reaches pathological levels. Objectives: The effects of five serotonergic drugs were compared to those of ethanol on a procedure for measuring tolerance to delay of reinforcement in rats in order to elucidate further the role of the serotonin systems in the regulation of impulsive behaviour. Methods: Rats were trained to choose between a single food pellet (small reinforcer) delivered immediately or five food pellets (large reinforcer) delivered after programmed delays. At the start of each session, there was no delay between the response and delivery of the large reinforcer, but this was increased stepwise during the session to delays of 10, 20, 40 and 60 s. Results: The rats showed consistent preference for the larger reinforcer when it was not delayed but showed a shift in preference as the session continued, so that they preferred the small reinforcer when the large was delayed by 40 or 60 s. Ethanol at a dose of 1.0 g/kg produced a significance increase in preference for the small, immediate reinforcer throughout the session, although there were marked individual differences in the size of the effect. A similar, but somewhat smaller effect was seen with the 5-HT2 agonist, DOI, at a dose of 1.0 mg/kg. In contrast, the 5-HT1A agonist, 8-OH-DPAT (0.3 mg/kg) reduced preference for the large reinforcer at the start of the session, and reduced preference for the small reinforcer at the end of the session, i.e. produced a regression to indifference. Lower doses of these three drugs, and treatment with the 5-HT receptor subtype selective antagonists WAY-100635 (5-HT1A: 0.01–0.1 mg/kg), ritanserin (5-HT2: 0.1 and 0.3 mg/kg) and MDL-72222 (5-HT3: 1.0 and 3.0 mg/kg) had no significant effects on reinforcer choice. Conclusion: These data show that ethanol and DOI increase preference for the immediate reinforcer, which can be construed as evidence of an increase in impulsive behaviour (reduction in self control), whereas selective blockade of the 5-HT1A, 5-HT2 or 5-HT3 receptors using selective antagonists does not affect self-control.
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  • 152
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 144 (1999), S. 111-120 
    ISSN: 1432-2072
    Schlagwort(e): Key words Heroin ; Self-administration ; Dependence ; Naloxone ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract   Rationale: Non-dependent and dependent opiate users appear to be driven by two distinct motivational factors: the primary reinforcing properties of the drug, and the negative reinforcing effects associated with relieving the negative affective component of opiate withdrawal in the dependent state. Objective: To investigate the motivational significance of opioid dependence on heroin self-administration (HSA) in rodents. Methods: Rats were trained to self-administer heroin intravenously (0.06 mg/kg per infusion; FR1), and opiate dependence was induced by subcutaneous implantation of two morphine (75 mg base) pellets.Rats in a non-dependent control group received placebo pellets. Three days after pellet implantation, HSA was resumed in daily 3-h sessions until baseline criteria were met and testing was conducted with subcutaneous injections of vehicle or naloxone (0, 0.003, 0.01, 0.03 mg/kg) 115 min into the session. Results: Morphine-dependent rats significantly increased HSA upon 0.01 mg/kg naloxone treatment, but decreased response rates at 0.03 mg/kg. Placebo pellet-implanted rats increased heroin intake at the 0.01 and 0.03 mg/kg doses. In a second experiment, the HSA session was shortened to 1 h and the training dose reduced to 0.03 mg/kg per infusion in new groups of animals. HSA in placebo pellet-implanted rats was increased only following the highest dose of the antagonist, while dependent rats were still affected by naloxone doses of 0.003–0.03 mg/kg. When subjected to a progressive-ratio schedule (experiment 3), breaking point values in dependent animals were 198% above baseline. Conclusions: The present study supports the hypothesis that dependence-induction by morphine-pellet implant in rats resulted in increased sensitivity to very small naloxone doses, as measured by changes in HSA. Taken together, these data suggest that opiate dependence, as measured by changes in sensitivity to naloxone, is a continuum which can contribute to the motivational state of drug-seeking.
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  • 153
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 144 (1999), S. 213-219 
    ISSN: 1432-2072
    Schlagwort(e): Key words Alcohol ; Self-administration ; Animal model ; Behavioral economics ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract   Rationale: For the purpose of investigating the determinants of preference for alcohol, it would be advantageous to use a procedure in which the subjects had concurrent access to alcohol and an isocaloric food. However, in widely used animal models, the introduction of a weak sucrose solution markedly reduced alcohol consumption. In contrast, when alcohol was sweetened, rats defended high baseline levels of alcohol intake despite access to chow, 10% sucrose, and increases in body weight that markedly reduced food consumption. Under these conditions, certain pharmacological treatments selectively reduced alcohol consumption. The present experiment further tests the generality of the contrast between food and sweetened alcohol consumption in rats. Objective: To test if rats will defend baseline levels of alcohol consumption when (1) the competing reinforcer is an isocaloric, preferred food and (2) when the cost of defending alcohol entails a decrease in food consumption as well as an increase in response output. Methods: The rats had access to a 10% alcohol plus 0.25% saccharin solution and an isocaloric, 14.8% Polycose solution in a two-lever, choice procedure. In the initial condition, the response requirement for each drink was set at five responses (variable-ratio 5); in subsequent conditions the variable-ratio values were increased to 7.5, 10, 15, and 30 responses. Results: In the initial condition, the rats drank twice as much Polycose as alcohol. However, with increases in the variable-ratio requirements, Polycose consumption systematically decreased, whereas sweetened alcohol consumption remained at its baseline level or above in all but the variable-ratio 30 condition. Conclusions: Rats defended baseline alcohol consumption but not baseline food consumption. As alcohol and food consumption can be dissociated in humans, research on the mechanisms that mediate alcohol regulated preference in rats may shed light on the mechanisms that control human alcohol consumption.
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  • 154
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 144 (1999), S. 239-247 
    ISSN: 1432-2072
    Schlagwort(e): Key words Dezocine ; Morphine ; 7-OH-DPAT ; Quinpirole ; SKF38393 ; SCH23390 ; Rat ; Warm-water tail-withdrawal ; Antinociception
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Rationale: The purpose of the present investigation was to evaluate the effects of the D3 agonist (±)-7-hydroxy-dipropylaminotetralin (7-OH-DPAT), various dopamine (DA) agonists and DA antagonists on the antinociceptive effects of μ opioids. Methods: Antinociception was assessed using a warm-water tail-withdrawal procedure in rats. Results: The μ opioids morphine (0.3–10 mg/kg) and dezocine (0.03–3.0 mg/kg) produced dose-dependent increases in antinociception with maximal effects obtained at the higher doses tested. Pretreatment with the putative D3 agonist 7-OH-DPAT (1.0–10 mg/kg) produced a dose-dependent attenuation of the antinociceptive effects of morphine and dezocine. At the highest dose of 7-OH-DPAT tested, the morphine dose-effect curve was shifted rightward by approximately 1.5 log units and the dezocine curve by greater than 2.3 log units. The (+)-isomer of 7-OH-DPAT (1.0 and 3.0 mg/kg) also shifted the morphine dose-effect curve to the right in a dose-dependent manner. The DA D3/D2 agonist (−)-quinpirole (0.1–10 mg/kg) attenuated the effects of morphine, but these effects were small in magnitude, not dose-dependent and observed only under a limited set of conditions. The DA D2/D3 antagonist spiperone failed to alter the morphine dose-effect curve, but reversed the effects of 7-OH-DPAT on morphine antinociception. Pretreatment with the DA D1 agonist (±)-SKF38393 (1.0 and 10 mg/kg) and the D1 antagonist (+)-SCH23390 (0.1 and 1.0 mg/kg) failed to alter the morphine dose-effect curve. Conclusion: The finding that 7-OH-DPAT markedly attenuated the effects of morphine and that these effects were reversed with spiperone suggests that activity at the D3, and possibly the D2, receptor can modulate μ agonist-induced antinociception.
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  • 155
    ISSN: 1432-2072
    Schlagwort(e): Key words GABAA receptor ; Propofol ; Midazolam ; NMDA receptor ; Ketamine ; Noradrenaline ; Medial prefrontal cortex ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: N-Methyl-d-aspartate (NMDA) receptor antagonism and GABAA receptor activation are believed to be critical targets for general anesthetic action. However, as NMDA antagonism of intravenous anesthetic agents causes post-anesthetic emergence reactions such as hallucination and agitation, while the GABAA-mimetic intravenous anesthetic agents do not, these two classes of intravenous anesthetic agents produce differential clinical profiles. Objective: We have investigated the differential effects of the GABAA agonists propofol and midazolam and the NMDA antagonist ketamine on noradrenaline release from the medial prefrontal cortex of the rat using microdialysis, as noradrenergic neurons have a role to play in anesthesia and are known to be important in the control of sleep, attention and learning. Methods: Twenty-one male Wistar rats (200– 270 g) were randomly allocated into three groups: ketamine 100 mg.kg–1 (n=6), propofol 60 mg.kg–1 (n=8) and midazolam 5 mg.kg–1 (n=7) IP. A unilateral guide cannula was implanted stereotaxically into the medial prefrontal cortex under pentobarbital anesthesia (50 mg.kg–1 IP). Forty-eight hours later, a dialysis probe was inserted through the guide cannula, and perfused with an artificial cerebrospinal fluid solution containing 1 mM pargyline. Following an equilibration period, samples of dialysate were collected every 10 min. Noradrenaline content was measured by high-performance liquid chromatography using an electrochemical detector. Results: Anesthesia times, defined as the duration between the loss of righting reflex and recovery, were 24.7±5.6 (SEM), 20.5±1.9 and 25.2±1.5 min for propofol, midazolam and ketamine, respectively (no significant between-group differences). Both GABAA agonists, propofol and midazolam, significantly decreased noradrenaline release (75% and 71% of basal release, respectively). The NMDA antagonist ketamine markedly increased noradrenaline release (413% of basal). Conclusion: These data suggest that different clinical profiles observed with these two classes of sedatives may result from changes in noradrenaline release from the medial prefrontal cortex.
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  • 156
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 146 (1999), S. 400-412 
    ISSN: 1432-2072
    Schlagwort(e): Key words Benzodiazepine ; Delay of reward ; Impulse control ; Muscimol ; pCPA ; Rat ; Serotonin ; Serotonin reuptake inhibitors ; 5-HT1A receptor ligands ; 5,7-DHT
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: Tolerance to delay of gratification, taken to reflect impulsiveness, has been proposed to be under the preferential control of central serotonin (5-HT) processes. Objective: The present study further examined the effects of drugs which directly or indirectly alter 5-HT transmission, on behaviour controlled by a delayed positive reinforcer. Methods: Rats were given the choice in a T-maze between two magnitudes of reward: small (two food pellets) and immediate versus large (ten pellets) but delayed. When a 15-s waiting period was imposed in the arm leading to the large reward, rats selected this arm on 65–70% of the trials. This frequency was reduced to less than 40% when the large reward was delayed by 25 s. Results: In rats whose ascending 5-HT pathways had been lesioned by infusion of 5,7-dihydroxytryptamine (5,7-DHT) into the dorsal raphe, the introduction of the 15-s delay contingency resulted in a transient larger reduction of the frequency of choice of the now-delayed reward, compared to sham operated controls. In contrast, choice behaviour of rats given 5,7-DHT into the substantia nigra did not differ from controls. para-Chlorophenylalanine (pCPA, 150 mg/kg IP, daily for 3 days), a 5-HT synthesis inhibitor, bretazenil (0.5-8 mg/kg IP), a benzodiazepine (BZD) receptor partial agonist, and muscimol (0.25-1 mg/kg IP), a GABAA receptor agonist, induced a shift toward immediate reward. In contrast to the other BZDs, alprazolam (1–2 mg/kg IP) enhanced the frequency of choice of the large-but-25 s-delayed reward. Similar increased preference for the large-but-delayed reward was induced by the selective 5-HT reuptake inhibitors, fluoxetine (4–8 mg/kg IP) and fluvoxamine (4 mg/kg IP). The full 5-HT1A receptor agonist, 8-OH-DPAT (0.015–0.5 mg/kg IP) enhanced the frequency of choice of the large reward delayed by 25 s, whereas the partial agonists, buspirone (1–4 mg/kg IP), ipsapirone (0.5–1 mg/kg IP) and MDL 73005EF (1–2 mg/kg SC), and the antagonist, WAY 100635 (4 mg/kg SC), reduced the number of choices of the large reward delayed by 15 s. Unexpectedly, WAY 100635 (2 mg/kg), which had no effect on choice whatever the delay, did not counteract the increased tolerance to delay induced by 8-OH-DPAT (0.06 mg/kg) and further reduced the frequency of choice of the large-but- 15 s-delayed reward induced by ipsapirone (0.5 mg/kg). Conclusions: These effects on tolerance to delay may be accounted for by a subtle balance between the opposing functional consequences of pre- versus post-synaptic 5-HT1A receptor activation or blockade. Overall, the present results provide further support to the idea that 5-HT processes participate in the control of impulsive-related behaviour, as assessed from tolerance to delay of reward in this particular T-maze procedure.
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  • 157
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 146 (1999), S. 432-439 
    ISSN: 1432-2072
    Schlagwort(e): Key words Impulsivity ; Choice ; Delay ; Methamphetamine ; Drug abuse ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: Moderate doses of d-amphetamine (given both acutely and chronically) have been shown to decrease impulsivity in children with attention deficit hyperactivity disorder (ADHD) and to improve attention and learning in normal adults. In contrast, chronic doses of methamphetamine (METH) in drug abusers have been associated with increased impulsivity, and impairments in learning and attention. Objectives: We report the effects of METH on an animal model of impulsive behavior. Methods: Rats were tested using the adjusting amount (AdjAmt) procedure in which the animals choose between a delayed fixed (large) amount of water and an immediate adjusting (small) amount of water. In the acute METH study, rats were given a single dose of 0.5, 1.0, 2.0, and 4.0 mg/kg METH or saline 30 min before testing. In the chronic METH study, we determined the effects of the 4.0 mg/kg dose of METH injected chronically 1 h after behavioral testing for 14 days. Thus the rats were tested using the AdjAmt procedure 22 h after injections of METH or saline. Results: After 0.5, 1.0 and 2.0 mg/kg METH, the rats valued the delayed large rewards more than after saline, indicating that the METH decreased impulsiveness. At the 4.0 mg/kg dose, the rats failed to respond. Rats treated repeatedly with the post-session large behaviorally disruptive dose of METH valued the delayed large rewards less than the saline-treated rats, indicating that this dosing regimen of METH increased impulsiveness. Conclusions: In these experiments, the rats became less impulsive after acute non-disruptive doses of pre-session METH, whereas they became more impulsive after receiving repeated post-session injections of a dose that was behaviorally disruptive when administered acutely.
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  • 158
    ISSN: 1432-1831
    Schlagwort(e): Key wordsToxoplasma gondii ; Toxoplasmosis ; Rat ; Animal model
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract There is evidence that not only the immune status, but also the genetic predisposition of certain hosts influence the clinical outcome of Toxoplasma gondii infection. By far the majority of our knowledge on genetic and immunological mechanisms involved in control of T. gondii infection has been obtained by studying mouse models, which in terms of clinical outcome of infection differ considerably from humans. Rats which show a rather similar course of infection in comparison to humans have not so far been investigated for effects of genetic differences on course of the infection. In this study we show that, like mice, different strains of rats exhibit a remarkable variation in the number of brain cysts arising from chronic infection. LEW rats seem to be highly resistant to cyst formation, in contrast to F344 rats that are susceptible. In addition, F344 rats express high numbers of γδ T cells during the acute phase of infection, whereas LEW rats express elevated but comparably low numbers of γδ T cells. The RT1 (rat MHC) haplotypes of both strains are identical in the RT1A and RT1B/D regions, which encode the restriction elements for conventional peptide antigens. Consequently, rat strain-specific differences may be useful to define MHC-independent mechanisms of resistance against T. gondii, which may also act in humans.
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  • 159
    ISSN: 1432-5233
    Schlagwort(e): Key words Cadmium ; Diabetes ; VEP ; TBARS ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Fifty-two healthy male Swiss albino rats, aged three months, were used in this study. They were divided into four groups: control (c), diabetic (D), cadmium (Cd), and diabetic + Cd (D+Cd). A diabetic condition was induced in D and D + Cd groups by administration of alloxane (5 mg/100 g). After this treatment, Cd and D + Cd groups were injected intraperitoneally with CdCl2 (2 mg/kg week). At the end of the 2-month experimental period, flash visual evoked potentials (FVEPs) of the four groups were recorded with disk electrodes attached with electrode paste 0.5 cm in front of and behind the bregma. The mean latencies off the P1, N1, P2, N2 and P3 components were significantly prolonged in the diabetic group compared with the control group. The mean latencies of P3 in the D + Cd group and of P1 and P3 in the Cd group were longer than those of the control group. P2N2 amplitude of Cd and D + Cd groups were significantly increased compared with the control group. On the other hand, thiobarbituric acid-reactive substances (TBARS) were determined as an indicator of lipid peroxidation. Our data showed that Cd treatment and diabetic condition caused a significant increase of lipid peroxidation in kidney, brain, retina and lens.
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  • 160
    ISSN: 1432-2277
    Schlagwort(e): Key words Xenotransplantation ; 15-deoxyspergualin ; Guinea pig ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This study aimed to investigate the effects of 15-deoxyspergualin (DSG), tacrolimus (FK 506) and cyclosporin A (CyA), alone or in combination, on delayed xenograft rejection (DXR). We used the guinea-pig-to-C6-deficient (C6–)-PVG-rat heart transplantation model, since in this strain combination, hyperacute rejection is avoided. In C6- control rats, the guinea pig xenografts survived for 39.2 ± 6.3 h (mean ± SD). Splenectomy alone resulted in a xenograft survival of 71.8 ± 7.8 h, but the addition of CyA or FK 506 did not further improve graft survival (73.6 ± 3.0 h and 72.0 ± 17.6 h, respectively). In contrast, DSG treatment increased graft survival to a mean of 99.8 ± 9.2 h. When CyA or FK 506 was combined with DSG, no additional effects were observed (105 ± 24.3 h and 95.1 ± 5.6 h, respectively). DSG alone or in combination with FK 506 or CyA resulted in a significant reduction in the serum IgM levels and reduced the deposits of IgM and IgG in rejected grafts. However, all xenografts were still heavily infiltrated by ED1 + macrophages, regardless of the treatment used. Thus, DSG treatment resulted in moderate prolongation of xenograft survival in C6– rats. The effect seems to be related to suppression of xenoreactive antibody production. To prolong xenograft survival further, strategies that inhibit macrophage infiltration seem required.
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  • 161
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 296 (1999), S. 235-246 
    ISSN: 1432-0878
    Schlagwort(e): Key words Transplantation ; Parkinson’s disease ; CNS fetal development ; CNS differentiation ; Neurotrophic factors ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract We have previously shown that a combination of the cytokines interleukin (IL)-1, IL-11, leukemia inhibitory factor (LIF), and glial cell line-derived neurotrophic factor (GDNF) can convert rat fetal (E14.5) mesencephalic progenitor cells into tyrosine hydroxylase (TH)-immunoreactive (ir) neurons in vitro. The experiments described here characterize the mesencephalic progenitor cells and their cytokine-induced conversion into dopamine (DA) neurons. For all experiments, we used bromodeoxyuridine (BrdU)-ir cultures of (E14.5) mesencephalic progenitor cells that had been expanded at least 21 days. We first demonstrated that IL-1 induced DA neuron conversion in mesencephalic progenitors, but not in striatal progenitors (P〈0.001). Thus, these cells should be classified as lineage-restricted progenitors, and not omnipotent stem cells. To further characterize cell populations in these cultures, we used monoclonal antibodies against Hu (an early marker for neurons), growth-associated protein (GAP)-43 (a marker for neuronal process extension), TH (a marker for DA neurons), and glial fibrillary acidic protein (GFAP, a marker for astrocytes). We assessed (E14.5) mesencephalic progenitor cell cultures (plated at 125,000 cells/cm2) incubated in the cytokine mixture (described above) or in complete media (CM, negative control). Following 7 days incubation, GFAP-positive cells formed a nearly confluent carpet in both types of cultures. However, numbers of Hu-ir and GAP-43-ir cells in the cytokine-incubated cultures far exceeded those in CM-incubated controls (P=0.0003, P=0.0001, respectively), while numbers of TH-ir cells were 58-fold greater in the cytokine-incubated cultures versus CM-incubated controls. The TH phenotype persisted for 7 days following withdrawal of the differentiation media. Numerous double-labeled cells that were BrdU-ir and also TH-ir, or Hu-ir and also TH-ir, were observed in the cytokine-incubated cultures. These data suggest that cytokines ”drive” the conversion of progenitor cells into DA neurons.
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  • 162
    ISSN: 1432-0878
    Schlagwort(e): Key words Subcommissural organ ; Isograft ; Xenograft ; Reissner’s fiber ; Cerebrospinal fluid ; Rat ; Bovine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  The subcommissural organ (SCO) secretes glycoproteins into the cerebrospinal fluid (CSF) that aggregate and form Reissner’s fiber (RF). The factors involved in this aggregation are not known. One factor may be the hydrodynamics of the CSF when flowing through the aqueduct. This hypothesis was tested by isografting rat SCO and xenografting bovine SCO into the lateral ventricle of rats. Xenografts were either fresh bovine SCO or explants cultured for 30 days before transplantation. The grafts were investigated by electron microscopy and immunocytochemistry using antibodies against RF glycoproteins, serotonin and the glucose transporter I. Maximal time of transplantation was 43 days for isografts and 14 days for xenografts. The isografts were not reinnervated but were revascularized; they secreted into the ventricle RF glycoproteins that became progressively packed into pre-RF and RF structures identical to those formed by the SCO in situ. RF was confined to the host ventricle and at its distal end the constituent proteins disassembled. Xenografts were neither reinnervated nor revascularized and secreted into the host ventricle a material that never formed an RF. These findings indicate that the CSF factor responsible for the formation of RF is species specific, and that this process does not depend on the hydrodynamics of the CSF. The blood vessels revascularizing the isografted SCO acquired the characteristics of the vessels irrigating the SCO in situ, namely, a tight endothelium displaying glucose transporter I, and a perivascular space containing long-spacing collagen, thus indicating that basal release of glycoproteins may also occur in the grafted SCO.
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  • 163
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 295 (1999), S. 55-64 
    ISSN: 1432-0878
    Schlagwort(e): Key words Axonal transport ; Purkinje cell ; Organotypic culture ; Microinjection ; Antimitotic drugs ; Cytoskeleton ; Dendritic transport ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Axonal and dendritic transport in single Purkinje neurons of cerebellar slice cultures was quantified as single transport distances. Examination of the cells within a vital tissue was regarded as being an approach to the in situ condition. The Purkinje cells were organotypically integrated in the in vitro tissues and extended long axonal projections connecting synapses to the target neurons. The tracer horseradish peroxidase (HRP) was applied via microinjection to the somata of the Purkinje cells and the injected neurons were incubated thereafter for defined time-intervals. The tracer was transported anterogradely into the neuron processes. The measurements on both the axonal and the dendritic transport of microinjected HRP revealed continuous transportation with increasing times of postincubation. This transport was reduced by the use of microtubule-depolymerizing drugs. The axonal transport of the tracer was either retarded in colchicine-treated cells or continuously reduced for up to 50% in vinblastine-treated neurons. Thus, a correlation of axonal transport to the microtubules was demonstrated. The dendrites were filled with the tracer after 60 min of postincubation. Dendritic transport was reduced by the use of vinblastine, and not significantly by colchicine. The results strongly support the dependence of neuronal transport on microtubules as a component of the cytoskeleton.
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  • 164
    ISSN: 1432-0878
    Schlagwort(e): Key words Neurofilament ; Basket cell ; Pinceau ; Golgi apparatus ; Calcium binding protein ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract NCS-1 (neuronal calcium sensor) is a recently characterized member of a highly conserved neuron-specific family of calcium-binding proteins, which also includes frequenin and recoverin. The cellular and subcellular distributions of NCS-1 in the rat nervous system were investigated using light- and electron-microscopic immunohistochemistry. NCS-1 immunoreactivity was localized to neuronal cell bodies and axons throughout the brain and spinal cord but not to glial cells. The most intense labeling was observed in myelinated axons, the axonal ramifications of the basket cell in the cerebellar cortex, and large neurons in the brainstem and pons. These same structures were also characterized by heavy labeling for neurofilament protein, as determined by double-labeling experiments. Most axon terminals were unlabeled or only lightly labeled. The most remarkable subcellular staining occurred in the perikarya where intense labeling was associated with the membranes of the trans saccules of the Golgi apparatus. The widespread distribution of NCS-1 indicates that it may be active in a variety of calcium-dependent neuronal functions, whereas the specific subcellular localization to the Golgi apparatus and neurofilament-rich structures suggests a specialized role in calcium regulated protein trafficking and cytoskeletal interactions.
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  • 165
    ISSN: 1432-0878
    Schlagwort(e): Key words Glial cell line-derived neurotrophic factor ; GDNF ; Ret ; GDNFR-α ; Brain-derived neurotrophic factor ; BDNF ; NT-3 ; NT-4 ; trk receptors ; Thyroid tissue ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Levels of mRNA for neurotrophins (brain-derived neurotrophic factor, BDNF; neurotrophin 3, NT-3; neurotrophin 4, NT-4) and their receptors (trkA, trkB, trkC) and for glial cell line-derived neurotrophic factor (GDNF) and its receptors (ret, GDNFR-α) were measured in rat thyroid tissue by ribonuclease protection assays. In thyroid tissue the NT-3 mRNA level was threefold lower and the NT-4 mRNA level sixfold higher than those detected in adult rat hippocampus, while BDNF mRNA was undetectable. Very low levels of mRNA for truncated trkB and trkC receptors and no catalytic trkA, trkB or trkC were found. In conclusion NT-3 and NT-4, but not the corresponding functional receptors, are expressed in the thyroid tissue. Therefore, it is unlikely that these factors serve a direct local autocrine or paracrine function in thyroid cell types, and a target-derived mode of action on neurons innervating the thyroid tissue is suggested. An opposite result has been found for the neurotrophic factor GDNF: thyroid tissue showed a high level of transcripts for the GDNF receptor subunits (GDNFR-α and Ret), while GDNF mRNA was undetectable. The in situ hybridization analysis of GDNFR-α and ret mRNA revealed an interesting difference in the cell distribution of these transcripts: ret mRNA is selectively expressed in a subpopulation of cells scattered in the follicular epithelium and in the interfollicular spaces, while GDNFR-α expression is more homogeneous and widespread, including the more abundant cell type of the thyroid gland: the follicular cell. Double-labeling in situ hybridization/immunocytochemistry experiments, with a specific marker (calcitonin), showed that parafollicular cells express ret but not GDNFR-α. This differential distribution of the GDNF receptor components (GDNFR-α and ret) may reflect a peculiar biological role in intercellular communication in the thyroid gland.
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  • 166
    ISSN: 1432-0878
    Schlagwort(e): Key words Water channel protein ; Aquaporin ; AQP5 ; Rat ; Salivary glands ; Immunolocalization ; Secretory stimulation ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Aquaporin-5 (AQP5) is a water channel protein and is considered to play an important role in water movement across the plasma membrane. We raised anti-AQP5 antibody and examined the localization of AQP5 protein in rat salivary and lacrimal glands by immunofluorescence microscopy. AQP5 was found in secretory acinar cells of submandibular, parotid, and sublingual glands, where it was restricted to apical membranes including intercellular secretory canaliculi. In the submandibular gland, abundant AQP5 was also found additionally at the apical membrane of intercalated duct cells. Upon stimulation by isoproterenol, apical staining for AQP5 in parotid acinar cells tended to appear as clusters of dots. These results suggest that AQP5 is one of the candidate molecules responsible for the water movement in the salivary glands.
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  • 167
    Digitale Medien
    Digitale Medien
    Springer
    Age 22 (1999), S. 19-25 
    ISSN: 1574-4647
    Schlagwort(e): Norepinephrine ; Aging ; Free Radicals ; Antioxidants ; Cerebellum ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The present review provides an overview of age-related changes in cerebellar β-adrenergic function, associated motor learning, causal agents and possible treatments. Norepinephrine acts as a neuromodulator of Purkinje cell activity. With aging, however, the ability of norepinephrine to modulate Purkinje cell activity and specifically GABAergic inhibition of Purkinje cell activity is decreased. This age-associated deficit in cerebellar noradrenergic function correlates with deficits in acquisition of a motor learning task. Aged rats are delayed in acquiring a motor learning task that requires rats to adjust footfalls in order to cross a runway. The degree of deficit in cerebellar β-adrenergic activity correlated positively with the degree of impairment in task acquisition. One possible causal agent for the β-adrenergic deficit is free radical damage. Hyperoxia, which may generate free radical damage, induces cerebellar β-adrenergic deficits in young rats but diet restriction and treatment with antioxidants can delay or reverse age-related deficits in cerebellar β-adrenergic function in old rats.
    Materialart: Digitale Medien
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  • 168
    Digitale Medien
    Digitale Medien
    Springer
    Personal and ubiquitous computing 3 (1999), S. 81-89 
    ISSN: 1617-4917
    Schlagwort(e): Child-centred participatory design ; Children ; Collaboration ; Education ; Handheld computing ; Learning environments
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Abstract Computers are becoming an important tool in learning environments; however, children's access to computer technology is often limited. Computers are commonly placed at the back of the classroom or in a separate computer room. At home, if computers are available, they are often found in a home-office or another communal area. In both cases, the physical location of the computers is separate from many places where children's activities and learning occur. Flexible access to technology will provide tools to help children construct knowledge throughout their daily activities. The growth of handheld computers provides the potential to integrate computer technology into the many facers of children's lives. This paper investigates issues surrounding the design of handheld computers for children's use in learning environments. It focuses on child-centred design, engaging children as active participants in the design of handheld technologies. Two central issues are addressed: mobility and sharability.
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  • 169
    Digitale Medien
    Digitale Medien
    Springer
    Personal and ubiquitous computing 3 (1999), S. 137-140 
    ISSN: 1617-4917
    Schlagwort(e): Children ; Product concept design ; Social aspects of fun ; User study
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Abstract This paper describes two explorative user studies conducted in a research project called Maypole. The purpose of the first user study was to understand how children thought communication with personal technologies could be fun. The second study focused on what children thought was fun in taking and editing digital images. In both studies, children aged 7–12 were given existing personal technologies to use in their own environment for one week. After that, a focus group was held with the children in order to discuss what they thought was fun in using the technologies. The results of the two user studies illustrate how fun in using personal technologies could relate to a user's social behaviour, and not only to human-computer interaction. Therefore, designers are encouraged to explore further the social aspects of fun in their creations. Moreover, the two studies illustrate some methodological problems in studying a user's experience of fun, which refer to a need for more public research on methods.
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  • 170
    ISSN: 1615-2573
    Schlagwort(e): Endomyocardial biopsy ; Dilated cardiomyopathy ; Children ; Ultrastructure ; Basal lamina layering of capillary
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We analyzed the electron-microscopic features of endomyocardial biopsy from pediatric patients with dilated cardiomyopathy (DCM). The specimens examined were taken from the right ventricle of ten patients aged from 2 to 15 years (mean 9.7 years). Biopsy specimens from eight patients with congenital heart disease (tetralogy of Fallot), aged from 3 to 12 (mean 7.3 years), and ten adult patients with DCM, aged from 32 to 60 (mean 45 years), were also examined. Patients considered to have endocardial fibroelastosis, arrhythmogenic right ventricular cardiomyopathy, specific cardiomyopathy, or coronary heart disease were excluded from this study. Specimens from pediatric patients with DCM showed various degrees of ultrastructural abnormalities of myocytes, including myofibrillar fragmentation, mitochondrial abnormalities, and intracellular edema. The ultrastructurally determined contractility failure index based on the severity of myocardial degeneration at the electronmicroscopic level was 4.9 ± 1.1. This value was significantly higher than that in patients with tetralogy of Fallot (0.9 ± 0.6,P 〈 0.001) but was not significantly different from that in adult patients with DCM (6.1 ± 2.6). The index of pediatric patients with DCM who died within 3 years was high (6.0 ± 0.8). Basal lamina layering of a capillary (BLL) in the myocardium was revealed in 1 of the 10 (10%) pediatric patients with DCM and in 6 of the 10 (60%) adult patients with DCM (P 〈 0.05). No BLL was noted in the patients with tetralogy of Fallot. These findings may be related to the pathogenesis of DCM in children and adults.
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  • 171
    Digitale Medien
    Digitale Medien
    Springer
    European journal of trauma 25 (1999), S. 254-266 
    ISSN: 1615-3146
    Schlagwort(e): Unterarmfraktur ; Kind ; Konservative/operative Therapie ; Forearm fractures ; Children ; Conservative/operative treatment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Abstract Forearm fractures rank among the most frequent injuries of children and adolescents. At our department, during a 5-year's period a total of 783 forearm fractures have been treated. The patient's age ranged between 1 and 17 years, with an average of 10.2 years. The vast majority were isolated forearm lesions without concomitant injuries, and the gender ratio of males to females was nearly 3 : 2. With 58.1% the left extremity was involved more frequently than the right one (40.4%), in 12 children (1.5%) fractures of both forearms were diagnosed simultaneously. Predominantly isolated radius fractures (59.1%) were seen, followed by complete forearm fractures (36.7%). Greenstick fractures occurred as frequent as 38.2%. With 78.7% the distal forearm was the most common location, followed by the middle and proximal shaft with 14.3% and 7.0%, respectively. Treatment was predominantly non-operative, only in 2.6% open reduction internal fixation (ORIF) became necessary. Therefore, majority treatment was outpatient and complications occurred very rarely. The data presented confirm the outstanding spontaneous correction capacity of the distal forearm in children in contrast to fractures located more proximally. Therefore, patients suffering from shaft fractures of the middle third have been invited to follow-up examinations revealing 44.4% excellent and good results, respectively. Fair and unsatisfying results have been found in 5.6% each. It could be demonstrated, that residual angulations of the middle third often overtax the organism's spontaneous correction capacity, at least as far as children aged 10 years and older are concerned. Therefore, in middle shaft forearm fractures in children generally should be reduced anatomically. If anatomical reposition and redression cannot be achieved conservatively, operative stabilization is indicated. We consider closed reduction and elastic stable intramedullary nailing (ESIN) the treatment of choice. In cases of higher degree open fractures or nerve lesions, revision with open reduction internal fixation (ORIF) using plates or external fixation are recommended, respectively.
    Notizen: Zusammenfassung Unterarmfrakturen gehören zu den häufigsten Verletzungen im Kindes- and Jugendalter. In einem Zeitraum von fünf Jahren wurden insgesamt 783 Kinder and Jugendliche im Alter von einem bis zu 17 Jahren mit Unterarmfrakturen behandelt. Der Altersdurchschnitt lag bei 10,2 Jahren. Es handelte sich vorwiegend um isolierte Verletzungen, and das Verhältnis von Jungen zu Mädchen lag bei 3 : 2. Der linke Arm war mit 58,1% häufiger betroffen als der rechte (40,4%), zwölf Kinder (1,5%) hatten doppelseitige Frakturen. Zum größten Ted (59,1%) handelte es sich um isolierte Radiusfrakturen, gefolgt von den kompletten Unterarmfrakturen (36,7%). In 38,2% der Fälle lagen Grünholzfrakturen vor. Die Frakturen des distalen Schaftdrittels wurden mit 78,7% am haufigsten gesehen, gefolgt von Brüchen des mittleren (14,3%) and proximalen (7,0%) Drittels. Die Therapie erfolgte vorwiegend konservativ, die osteosynthetische Versorgung wurde nur in 2,6% der Fälle erforderlich. Somit konnte die Behandlung meist ambulant erfolgen, and Komplikationen waren außerordentlich selten. Das gute Spontankorrekturpotential kindlicher Unterarmfrakturen des distalen Drittels gegenüber weiter proximal gelegenen Frakturen bestätigte sich in der vorliegenden Untersuchung. Daher wurden die Patienten mit Frakturen des mittleren Drittels — soweit erreichbar - embestellt and eingehend nachuntersucht. Hierbei fanden sich in jeweils 44,4% der Fälle sehr gute and gute funktionelle Ergebnisse. Befriedigende and schlechte Behandlungsresultate wiesen je 5,6% der Patienten auf. Es zeigte sich, daß belassene Achsfehlstellungen im mittleren Drittel vor allem nach Erreichen des zehnten Lebensjahres die spontane Korrekturfähigkeit im Rahmen des weiteren Wachstums häufig überfordern and mit einem Ausgleich der Fehlstellung daher nicht regelhaft gerechnet werden darf. Daher sollten Unterarmfrakturen des mittleren Schaftdrittels bei Kindern anatomiegerecht reponiert werden. Gelingen Reposition oder Retention auf konservativem Wege nicht, ist die Indikation zur osteosynthetischen Versorgung gegeben. Hier empfiehlt sich, außer bei höhergradig offenen Frakturen oder Nervenschäden, als Therapie der ersten Wahl die geschlossene Reposition in Narkose mit elastisch-stabiler Markraumschienung (ESM). Dieses Osteosyntheseverfahren birgt gleichzeitig die Vorteile des kleineren operativen Traumas mit Verkürzung von Ruhigstellung (Gipsbehandlung) and Krankenhausaufenthalt. Schlüsselwörter: Unterarmfraktur - Kind - Konservative/operative Therapie
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  • 172
    ISSN: 1619-7089
    Schlagwort(e): Key words:Helicobacter pylori ; Carbon-14 urea breath test ; Biokinetics ; Dosimetry ; Children
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. The long-term biokinetics and dosimetry of carbon-14 were studied in nine adults and eight children undergoing carbon-14 urea breath test for Helicobacter pylori (HP) infection. The elimination of 14C via exhaled air and urine was measured with the liquid scintillation counting technique and with accelerator mass spectrometry. After the subjects had been given 110 kBq 14C-urea (children: 55 kBq) orally, samples of exhaled air were taken up to 180 days after administration and samples of urine were collected up to 40 days. Sixteen of the subjects were found to be HP-negative. In these subjects a total of 91.1%±3.9% (mean of adults and children ± standard error of the mean) of the administered 14C activity was recovered. The majority of the administered activity, 88.3%±6.2% in adults and 87.7%±5.0% in children, was excreted via the urine within 72 h after administration. A smaller fraction was exhaled. In adults 4.6%±0.6% of the activity was exhaled within 20 days and in children 2.6%±0.3%. Uncertainties in the biokinetic results are mainly due to assumptions concerning endogenous CO2 production and urinary excretion rate and are estimated to be less than 30%. The absorbed dose to various organs and the effective dose were calculated using the ICRP model for urea and CO2. The urinary bladder received the highest absorbed dose: in adults, 0.15±0.01 mGy/MBq and in children of various ages (7–14 years), 0.14–0.36 mGy/MBq. The findings indicate that an investigation with 14C-urea gives an effective dose to adults of 2.1±0.1 µSv (for 110 kBq) and to children of 0.9–2.5 µSv (for 55 kBq). From a radiation protection point of view, there is thus no reason for restrictions on even repeated screening investigations with 14C-urea in whole families, including children.
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  • 173
    Digitale Medien
    Digitale Medien
    Springer
    International journal of anthropology 14 (1999), S. 55-59 
    ISSN: 1824-3096
    Schlagwort(e): Ascaris ; Nutrition ; I.Q. ; Children ; Egypt
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract It was estimated that about 1.3 billion persons all over the world were infected with Ascaris Lumbricoides (A.L.), Especially children in tropical and subtropical countries. AIM To investigate the effects of A.L. infection on the nutritional status and the intellectual level in a sample of Egyptian primary school children from rural Giza province. SUBJECTS AND METHODS A sample of 637 children (329 boys and 308 girls) aged 6–12 years, have been subjected to some anthropometric measurements including body weight, body height, arm circumference, head circumference and triceps skinfold thickness. In addition, the I.Q. was determined using “Draw-a-man” test. Blood hemoglobin concentration was also determined using a spectrophotometric method. All the children were then subjected to stools and urine examinations, and peri-anal swab. Only 242 children were included for further study, of whom 45 boys and 38 girls were found infected with A.L. solely, and 81 boys and 78 girls of about the same age free of parasitic infections were taken as control. RESULTS Children infected with A.L. has significantly lower body weight, height, and arm circumference but insignificantly lower skinfold thickness and head circumference as comparedto the control group. Infected children had significantly lower hemoglobin concentration and I.Q. than the controls. CONCLUSIONS Selected anthropometric measurements, biochemical and intellectual tests from a useful complementary battery for reliable and informative investigation of the effects of parasitic infection on child nutrition and health. A.L. was found to have a significant effect on the physical and intellectual status of the rural Egyptian children of age 6–12 years.
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  • 174
    Digitale Medien
    Digitale Medien
    Springer
    European journal of applied physiology 79 (1999), S. 504-511 
    ISSN: 1439-6327
    Schlagwort(e): Key words Co-activation ; Children ; Knee ; Electromyography ; Isokinetic
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Determining the mechanisms of co-activation around the knee joint with respect to age and sex is important in terms of our greater understanding of strength development. The purpose of this study was to examine the effects of age, sex and muscle action on moment of force and electromyographic (EMG) activity of the agonist and antagonist muscle groups during isokinetic eccentric and concentric knee extension and flexion. The study comprised nine pubertal boys [mean age 12.6 (SD 0.5) years], nine girls [12.7 (SD 0.5) years] nine adult men [23.1 (SD 2.1) years] and nine adult women [23.7 (SD 3.1) years] who performed maximal isometric eccentric and concentric efforts of knee extensors and flexors on a dynamometer at 30° · s−1. The moment of force and surface EMG activity of vastus lateralis and biceps femoris muscles were recorded. The moment of force:agonist averaged EMG (aEMG) ratios were calculated. The antagonist aEMG values were expressed as a percentage of the aEMG activity of the same muscle, at the same angle, angular velocity and muscle action when the muscle was acting as agonist. Three-way analysis of variance (ANOVA) designs indicated no significant effects of age or sex on moment:aEMG ratios. Eccentric ratios were significantly higher than the corresponding concentric ones (P 〈 0.05). The results also indicated no significant effect of age and sex on the aEMG of the vastus lateralis and biceps femoris muscles when acting as antagonists. The antagonist aEMG was significantly greater during concentric agonist efforts compared with the corresponding eccentric ones (P 〈 0.05). These findings would suggest that the moment exerted per unit of agonist EMG and the antagonist activity are similar in children compared with adults and are not sex dependent. Future comparisons between eccentric and concentric moments of force and agonist ENG should take into consideration the antagonist effects, irrespective of age or sex.
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  • 175
    Digitale Medien
    Digitale Medien
    Springer
    European journal of applied physiology 80 (1999), S. 118-124 
    ISSN: 1439-6327
    Schlagwort(e): Key words Exercise ; Children ; Ventilation ; Gas exchange
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The purposes of this investigation were to quantify the noise component of child breath-by-breath data, investigate the major determinants of the breath-to-breath noise, and to characterise the noise statistically. Twenty-four healthy children (12 males and 12 females) of mean (SD) age 13.1 (0.3) years completed 25 min of steady-state cycle ergometry at an exercise intensity of 50 W. Ventilatory and gas exchange variables were computed breath-by-breath. The mean (SD) oxygen consumption (V˙O2) ranged from 0.72 (0.16) to 0.92 (0.26) l · min−1; mean (SD) carbon dioxide production (V˙CO2) ranged from 0.67 (0.20) l · min−1 to 0.85 (0.16) l · min−1; and mean (SD) minute ventilation ranged from 17.81 (3.54) l · min−1 to 24.97 (5.63) l · min−1. The majority of the breath-to-breath noise distributions differed significantly from Gaussian distributions with equivalent mean and SD parameters. The values of the normalised autocorrelation functions indicated a negligible breath-to-breath correlation. Tidal volume accounted for the majority of the V˙O2 (43%) and V˙CO2 (49%) variance. The breath-to-breath noise can be explained in terms of variations in the breathing pattern, although the large noise magnitude, together with the relatively small attainable response amplitudes in children reduces the certainty with which ventilatory and gas exchange kinetics can be measured.
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  • 176
    Digitale Medien
    Digitale Medien
    Springer
    European journal of applied physiology 80 (1999), S. 344-352 
    ISSN: 1439-6327
    Schlagwort(e): Key words Endurance running ; Bone density ; Deoxypyridinoline ; Osteocalcin ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This experiment was performed to study the effects on femoral bone of endurance training performed during the 3 months before orchidectomy in rats which were then killed 90 days later. A total of 70 male Wistar rats were used at 8 weeks old. One day 0 of the experiment, 10 rats were killed by cervical dislocation and used as first controls. Among the 60 others, 30 were selected for treadmill running (60% maximal oxygen uptake, 1 h · day−1, 6 days · week−1 for 90 days). The 30 other rats remained at rest. On day 90, 10 exercised (IE) and resting (IR) rats were killed and used as intermediary controls. Among the 20 other animals of each group, 10 were surgically castrated (CXE, CXR) or 10 sham-operated (SHE, SHR) and killed on day 180. On day 90 femoral failure load (three-point bending test) was greater in IE than in IR. Simultaneously, the deoxypyridinolinuria was lower in IE than in IR. On day 180, femoral bones were thinner in CXR than in CXE. The lowest values for trabecular bone are in the distal femoral metaphysis were measured in CXE and CXR rats, but the value measured in CXE was no different from that measured in SHR. Simultaneously total femoral bone density was lower in CXR than in SHE, while no difference concerning femoral metaphyseal density was observed between CXE and SHR. These results confirmed that endurance running increased femoral bone growth and modelling and femoral trabecular area, and thereby peak bone mass, in 8-month-old male rats. In resting animals, castrated after the training period, androgen deficiency decreased femoral density, mineral content and trabecular area. This decrease was not observed in castrated but previously exercised rats. Thus, by increasing peak bone mass, it was considered that endurance training may have a preventive effect against orchidectomy-induced bone loss.
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  • 177
    ISSN: 1439-6327
    Schlagwort(e): Key words Bone ; Deoxypyridinoline ; Osteocalcin ; Rat ; Treadmill running
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The present study was designed to provide data on the effects on femoral bone of endurance training starting only 3 months after orchidectomy in rats. A total of 70 Wistar male rats were used at 8 weeks of age. On day 0 of the experiment, 10 rats were killed by cervical dislocation to be used as first controls. Among the 60 other animals, half was surgically castrated (CX) or sham operated (SH). On day 90, 10 CX and 10 SH were killed and used as intermediary controls (ICX and ISH). Among the other 20 CX and 20 SH, 10 within each group (CXE, SHE) were selected for treadmill running (60% maximal oxygen uptake, 1 h · day−1, 5 days · week−1 for 12 weeks). The 20 other rats were used as sedentary controls (CXR, SHR) and killed (as runners) on day 180. On day 90 femoral bone density (BMD) and mineral content (BMC) were lower in ICX than in ISH. On day 180 total femoral BMD was lower in CXR than in CXE. Simultaneously metaphyseal femoral BMD was lower in CXR than in CXE, SHR or SHE. Furthermore, at that time, no significant difference concerning BMD and BMC was observed between SHR and CXE. This would indicate that treadmill running starting only 3 months after orchidectomy is able to restore BMD and BMC to control values, mainly by inhibiting bone resorption (as shown by decreased urinary deoxypyridinoline excretion in CXE) without decreasing osteoblastic activity (evaluated by plasma osteocalcin concentration).
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  • 178
    ISSN: 1573-7284
    Schlagwort(e): Asthma ; Atopic diseases ; Children ; Epidemiology ; Socio-economic status ; Tobacco smoke
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A cross-sectional survey of a cohort study was carried out between June and December 1994 in Valencia, Spain (population in 1994: 764,293 inhabitants). Two hundred sixty public and private schools randomly selected from the total of schools in Valencia were invited to participate; 3948 children aged 6–7 years cooperated in our study after informed consent was obtained from parents and school director. The survey in Valencia is part of the International Study of Asthma and Allergy in Childhood (ISAAC). Prevalences for asthma, rhinitis and atopic dermatitis were determined and contrasted with socioeconomic status (SES) among children. No statistically significant associations were established between the prevalences of asthma, rhinitis and atopic dermatitis, and SES. However, atopic dermatitis was found to be common among upper class children (21.5 per 100 children). Likewise, significant associations were observed between the severity of atopy (2 or 3 atopic manifestations) and SES (p=0.000), being greater for lower strata (4.5 per 100 children); for the three SES level significant differences were established (p = 0.008) regarding passive exposure to tobacco smoke in the home.
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  • 179
    ISSN: 1573-7284
    Schlagwort(e): Children ; Clinical characteristics ; Lower respiratory tract infections ; Nosocomial infections ; Respiratory syncytial virus ; Therapy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This paper has analyzed respiratory syncytial virus lower respiratory tract infections in 201 hospitalized children. In children with wheezing, erythrocyte sedimentation rate (ESR) was significantly higher in those with pneumonia than with syndroma pertussis, while the white blood cell (WBC) count was significantly lower in patients with bronchitis than in those with bronchiolitis and syndroma pertussis. Bronchodilatators were applied in 75.6% and corticosteroids in 20% of patients. Ten patients were ventilated. Fatal disease outcome was observed in one infant. Twelve consecutive-year study of respiratory syncytial virus (RSV) infections showed that 27.3% of these diseases were bronchiolitis and pneumonia.
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  • 180
    Digitale Medien
    Digitale Medien
    Springer
    Pharmacy world & science 21 (1999), S. 168-172 
    ISSN: 1573-739X
    Schlagwort(e): Adenoidectomy ; Children ; Day‐case surgery ; Home care ; Pain medication ; Postoperative pain ; Tonsillectomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The aim of this study was to describe how parents manage their child's postoperative pain at home following day‐case surgery. The incidence of pain, different analgesics used and problems related to administering medications were the main interests of the study. A postal questionnaire was sent to the parents of 275 children who were under 8 years of age and had undergone an ear, nose and throat (ENT) day‐case operation. The questionnaire was sent to the parents a week after discharge from hospital. Altogether, the parents of 227 children answered the questionnaire (response rate 83%). The study was divided into two phases (preintervention and postintervention), and incorporated a training program for doctors and nurses between these two phases. The training program aimed to improve the treatment practices of postoperative pain in children. Seventy‐eight per cent of the children in the preintervention study and 75% in the postintervention study experienced at least mild pain after discharge. The training program for doctors and nurses affected the home treatment practices of postoperative pain. The proportion of parents treating their children increased from 68% to 80% after the training program (p=0.028). Many parents faced problems while treating their children; for example, 19% (n=30) of the children refused to take their medicine, and suppositories were regarded to be an especially unpleasant dosage form. However, no serious adverse effects were reported. We conclude that due to the pain experienced at home by the great majority of children following day‐case ENT operations, parents need information on how to manage their child's pain. A training program for doctors and nurses can improve the treatment of children's pain even at home. Since some children dislike suppositories, it would be worth considering the use of small tablets or mixtures instead.
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  • 181
    Digitale Medien
    Digitale Medien
    Springer
    Child psychiatry & human development 29 (1999), S. 261-276 
    ISSN: 1573-3327
    Schlagwort(e): Children ; Obsessive-Compulsive ; Rituals ; Fear
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This study examined the relationship between ritualistic, compulsive-like behaviors and normative fears and phobias in 61 children ranging from 1 to 7 years of age. Parents reported on their children's ritualistic habits, and perfectionistic behaviors that reflect what we have previously called “compulsive-like” behaviors. Parents also reported on their children's fears and phobias. Results indicated that various aspects of children's ritualistic and compulsive-like behaviors are correlated with children's fears and phobias. Developmental differences existed such that younger children's (〈 4 years) repetitive, compulsive-like behaviors were related to “prepotent” fears such as stranger and separation anxieties, whereas the compulsive-like behaviors of older children (〉 4 years) were correlated with more specific, “contextual” fears such as fears of contamination, death, and fears often associated with concerns of the inner city such as burglars, assault, etc. These findings are discussed in terms of the phenomenologic and possible neurobiological continuities between normative and pathologic rituals, fears and phobias.
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  • 182
    Digitale Medien
    Digitale Medien
    Springer
    Child psychiatry & human development 30 (1999), S. 29-37 
    ISSN: 1573-3327
    Schlagwort(e): In-School Intervention ; Suspensions ; Reading ; Consistency ; Parents ; Schools ; Children ; Bullies ; Victims ; Anti-social Behavior
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This study developed a method of in-school intervention that dramatically reduced the suspension rate and violence in elementary schools. It suggests that children who were not read to by their parents often become bullies and/or victims of bullies. Other parental practices, including inconsistent discipline in the home, also may be contributing factors.
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  • 183
    ISSN: 1573-9104
    Schlagwort(e): Bioavailability ; Magnesium ; Hijiki ; Sodium alginate ; Rat ; Wakame
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The bioavailability of magnesium from Wakame and Hijiki, and the effects of alginic acid on absorption of dietary magnesium were examined in five groups of rats fed either control, Wakame, Hijiki, AW (containing the same amount of alginate as in the Wakame) and AH (containing the same amount of alginate as in the Hijiki) diets, and animals fed a low magnesium diet (LMg) (twentieth amount of magnesium in the original mineral mixtures as the control). Food intake and body weight gain were decreased by adding sodium alginate to the diets. A large amount of calcium accumulated only in the kidneys of the rats fed the LMg diet. Serum magnesium concentration decreased only in the LMg group. The magnesium content in the defatted left femurs did not differ between the control and Wakame fed animals and also among the animals eating Wakame, Hijiki and AW diets. The breaking force of the right femurs did not differ among all the groups except the LMg group. The ratio of apparent magnesium absorption (%) of the control, LMg, Wakame, Hijiki, AW and AH groups was 82.2, 72.7, 66.9, 50.8, 69.3 and 54.2 in the first experimental period, and was 75.3, 52.1, 57.7, 46.9, 62.6 and 60.5 in the second experimental period, respectively. It was clear that the bioavailability of magnesium in the Wakame fed rats was higher than in those eating the Hijiki. Large amounts of sodium alginate lowered magnesium absorption from the diet.
    Materialart: Digitale Medien
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  • 184
    ISSN: 1433-0385
    Schlagwort(e): Key words: Hernia repair ; Children ; Laparoscopy ; Patient selection. ; Schlüsselwörter: Kinderchirurgie ; Leistenhernie ; intraoperative Laparoskopie ; Diagnostik ; Patientenselektion.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung. Aus epidemiologischen Untersuchungen ist bekannt, daß bei ca. 50 % der Kinder mit einseitiger Leistenhernie auf der Gegenseite ebenfalls ein offener Processus vaginalis vorliegt. 10–25 % dieser Kinder entwickeln in der Folge eine kontralaterale Hernie. Seit 1996 wird in unserer Klinik bei Säuglingen und Kindern mit klinisch unilateraler Leistenhernie mittels intraoperativer Laparoskopie durch den eröffneten Bruchsack der kontralaterale innere Leistenring inspiziert. Vorgehen: Bisher wurden 112 Kinder untersucht (Alter: 6 Monate bis 7 Jahre; 78 Jungen, 34 Mädchen). Nach Freipräparation des Bruchsacks wurde dieser eröffnet und ein 5,5-mm-Trokar durch den inneren Leistenring eingebracht. Nach Anlage des Pneumoperitoneums erfolgte mit einer 5-mm-(30 °)-Optik zunächst die orientierende Laparoskopie, anschließend mit der 70 °-Optik die Inspektion des kontralateralen inneren Leistenrings. Ergaben sich Hinweise für einen breit offenen Processus vaginalis (Typ III nach Chin), wurde in gleicher Narkose diese Seite ebenfalls offen chirurgisch exploriert. Ergebnisse: Laparoskopisch fand sich bei 19 Patienten (17 %) ein nach oben genannten Kriterien pathologischer Befund (6 Mädchen, 13 Jungen). Diese wurden auf der Gegenseite operiert und die laparoskopische Diagnose in allen Fällen bestätigt. Verfahrensbedingte Komplikationen traten nicht auf. Die Eingriffe erfolgten im Rahmen der Eintageschirurgie. Die Operationsdauer erhöhte sich durch die intraoperative Laparoskopie um im Median 6 min (3–11 min). Deutlich häufiger fanden sich pathologische Befunde bei Patienten unter 2 Jahren (14 von 19 Patienten). Schlußfolgerungen: Das beschriebene Verfahren erlaubt ohne nennenswerten zusätzlichen Zeitbedarf, Patienten zu selektionieren, die von einer einzeitigen offenen Exploration der gegenseitigen Leistenregion profitieren. Somit können Zweitoperationen mit erneuter Narkose und Hospitalisierung vermieden werden. Zusätzlich erlaubt die intraoperative Laparoskopie die allgemeine Beurteilung der Abdominalorgane sowie Klärung spezieller Fragen wie, z. B. die Vitalität reponierter Darmschlingen.
    Notizen: Summary. Background: Approximately 50 % of children with a clinical unilateral inguinal hernia display a patent processus vaginalis on the contralateral side; half of these children subsequently develop an inguinal hernia.The management of this problem is still controversial. The purpose of this study was to evaluate the usefulness of intraoperative laparoscopy in a no-puncture technique through the opened hernia sack. Method: In 112 children (age 6 months to 7 years ) with clinical unilateral hernia laparoscopy (5 mm laparoscope, 30 ° and 70 °). In cases of a wide-open contralateral internal inguinal ring (type III) open surgical exploration was performed. Results: Nineteen patients (17 %) fulfilled the laparoscopic criteria of a type III ring; the diagnose was confirmed during open contralateral exploration. Fourteen of these patients were younger than two years. The median time for laparoscopy was 6 min (3–11 min). No complications associated with the laparoscopy were observed. Conclusions: Intraoperative laparoscopy during unilateral hernia repair allows the identification of patients who profit from bilateral open surgery during the same operation with little additional operating time and so far with no resulting complications. Application of this method may avoid a second hospitalization and operation, as well as an unnecessary routine bilateral open exploration. As an additional source of information through excellent visualization of the abdominal cavity, this method proved helpful to examine incarcerated bowel after repositioning.
    Materialart: Digitale Medien
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  • 185
    Digitale Medien
    Digitale Medien
    Springer
    European journal of epidemiology 15 (1999), S. 133-139 
    ISSN: 1573-7284
    Schlagwort(e): Children ; Emergency room charge ; Hospitalisation ; Injuries ; Socio-economic
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Although many studies have shown an association between socio- economic environment and childhood injury mortality rates, little research has focused on the association between injuries which require hospitalisation and the child's socio-economic environment. All municipal emergency care was free of charge before the beginning of 1991, from then on a moderate patient charge was introduced by the City of Helsinki. An earlier report from a completely different social environment suggest that even a moderate user charge might create systematic discrimination against indigent families. We studied the childhood injury hospitalisation rates during 1989–1994 in Helsinki and analysed the association between rates of hospitalisation and local socio-economic and demographic factors. We also examined the effect of introduction of emergency room user charges on the rate of hospitalisation. Data from 1607 injuries from Helsinki City Hospital and 769 injuries from Helsinki University Central Hospital from years 1989 through 1994 were used. Annual rates of child hospitalisation were calculated at city level. Local socio-economic and demographic variables were derived from the Helsinki Bureau of Statistics. The possible association between the explanatory variables and hospitalisation rates at Helsinki City Hospital was calculated using annual data from the 33 health districts in Helsinki. The overall rate of hospitalisation for injuries declined but not statistically significantly. No association between socio-economic and demographic variables and hospitalisation rates was found. The moderate user charge had no effect on hospitalisation rates, proving that, in this setting, the demand for care was rather inelastic in paediatric injuries severe enough to require hospitalisation.
    Materialart: Digitale Medien
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  • 186
    Digitale Medien
    Digitale Medien
    Springer
    European journal of epidemiology 15 (1999), S. 907-912 
    ISSN: 1573-7284
    Schlagwort(e): Bedouin ; Children ; Diarrhea ; Environment ; Knowledge
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Diarrhea is still a major cause of morbidity and mortality among children in developing countries. As it is due to multiple causative agents including viruses, bacteria and parasites, biological interventions are not currently available to markedly reduce incidence and severity. We examined maternal knowledge and reported behavior during diarrheal episodes, as well as environmental factors to determine their association with diarrhea. The children and mothers were from a Bedouin township in southern Israel, which has developed preventive and curative health care facilities. The Bedouin population in Israel is in transition from a nomadic to a settled life style. While almost all mothers exhibited good knowledge regarding food storage and prevention of diarrhea episodes in the children, the rate of illness in the children remained relatively high (two episodes per child year of observation). In a multivariate analysis, cessation of breastfeeding during diarrhea, child sleeping with siblings and lack knowledge about risk factors, were the major risk factors for illness with odds ratios (OR): 4.6, p = 0.02, 5.6, p = 0.03 and 1.7, p = 0.06, respectively. These data indicate that even in this population with free access to preventive medical care, greater efforts should be made to educate mothers regarding risk factor for diarrheal disease identification and the benefits of maintaining breastfeeding during diarrhea episodes.
    Materialart: Digitale Medien
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  • 187
    Digitale Medien
    Digitale Medien
    Springer
    European journal of epidemiology 15 (1999), S. 485-491 
    ISSN: 1573-7284
    Schlagwort(e): Blood lead levels ; Children ; Modeling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The key problem in environmental health is to identify the potential health hazards at the lowest possible cost based upon available environmental data. Biokinetic models such as IEUBK Lead 0.99d are very promising in this respect. We attempted a comparison between epidemiological data and predictions of the model. As input, we used the existing exposure data for the Katowice Voivodship (administrative district, Poland). Epidemiological analysis was based on the results of the screening programme ‘Prevention of the Environmental Lead Intoxication in Children Living in Katowice Voivodship’. The simulations consisted of predicted distributions of blood lead levels in children. They have been compared with observed distributions. Sensitivity analysis of simulations with respect to lead concentration in air, soil, water and diet has also been performed. The agreement between predicted and observed mean blood lead levels was quite good (relative difference of about 40%) as for the coarse exposure assessment employed. At the level of risk (fraction of population having blood lead levels exceeding 10 μg/dl) the difference is much higher (about a factor of 2). In order to explain this discrepancy we checked the goodness of fit for the log-normal distribution function (usually taken as a template distribution for lead in the population) in the right tail of the distribution. We noticed a systematic effect depleting the right tail of the actual distribution as compared with the log-normal one. Therefore one can expect that using (as a template) another skewed distribution better fitted in the right tail would improve the accuracy of risk assessment.
    Materialart: Digitale Medien
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  • 188
    ISSN: 1573-7284
    Schlagwort(e): Children ; ELISA ; Haemophilus influenzae type b ; Infants ; Natural immunity ; Vaccination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Prior to possible introduction of large-scale vaccination programmes, an estimation and comparison of naturally acquired immunity against Haemophilus influenzae type b (Hib) was carried out in two populations of age-stratified infants and children (from birth to 14 years old) in Burkina-Faso (West Africa) (n = 206) and France (n = 206). Hib capsular polysaccharide antibodies were detected by an ELISA method. The difference in the percentages of minimum protective levels for the two populations were not significant (0.15 μg/ml) for newborns (0–1 month) but became significant as early as 2 to 3 months of age (p 〈 0.01) when lower levels were found among infants from Burkina-Faso. Subsequently, the percentages in both countries remained low until 11 months of age and showed no significant differences. For children between 12 and 35 months, the results ≥ 0.15 μg/ml were significantly higher in France (p ≤ 0.05). From 36 months, the percentage of minimum seropositivity increased in Burkina-Faso, so that the difference was no longer significant. In each country, the percentage of children with the minimum protective level varied significantly (p les; 0.05) according to age (0–47 months). None of the children from Burkina-Faso or France had antibody levels 〉 1.0 μg/ml before one year of age. Thereafter, only 9.51% of French children in the 12- to 17-month age stratum and 19.2% over 4 years of age had antibody levels 〉 1.0 μg/ml. There were no non-detectable results for children over 4 years of age, and the means for natural detectable Hib CP antibodies were 〉 0.15 μg/ml for both populations. Hib invasive infections depend on climate, socioeconomic status and ethnic and genetic factors. In Burkina-Faso, the large number of infants and children under 4 years of age susceptible to Hib infections suggests that large scale vaccination programmes are needed soon after birth. However, it would first be necessary to evaluate such factors as the frequency of Hib diseases in this population.
    Materialart: Digitale Medien
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  • 189
    Digitale Medien
    Digitale Medien
    Springer
    European journal of epidemiology 15 (1999), S. 685-687 
    ISSN: 1573-7284
    Schlagwort(e): Children ; Epidemiology ; Hib meningitis ; Italy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In 1994, the Italian Ministry of Health implemented a National Surveillance System to obtain data on the incidence of bacterial meningitis and its causative agents, including Haemophilus influenzae type b (Hib). As a consequence, case reporting of Hib meningitis is increasing year by year; in 1996, there were 126 notifications, of which 73% were in children under 2 years of age. Although underreporting still exists, parallel prospective or retrospective epidemiological surveys conducted in some Italian Regions allowed for partial correction of the incidence of Hib meningitis (up to 18.5/100,000 population in 1994).
    Materialart: Digitale Medien
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  • 190
    Digitale Medien
    Digitale Medien
    Springer
    Langenbeck's archives of surgery 384 (1999), S. 461-466 
    ISSN: 1435-2451
    Schlagwort(e): Key words Liver transplantation ; Bile salt ; Tauroursodeoxycholate ; Rat ; Reperfusion injury
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Introduction: Tauroursodeoxycholate (TUDC) is used routinely in the treatment of cholestatic liver disease. The present study was designed to determine whether it would mitigate ischemia/reperfusion injury in an in vivo pig liver-transplantation model. Methods: Transplantation was performed in 12 animals after a preservation time of 8 h. In the control group (n=6), 0.9% saline was infused into the donor. In the experimental group (n=6), TUDC was given intravenously at a rate of 2 µmol/kg body weight per minute. In the recipient, infusion was started at the time of reperfusion; saline was infused for 400 min in the control group, TUDC for the same duration at a rate of 0.2 µmol/kg body weight per minute in the experimental group. Blood was drawn for determination of liver enzymes. Bile samples were collected and bile flow (BF) and bile salt secretion rate (BSSR) were determined. Results: One-week survival was 92% and not different among groups. Liver enzymes were lower in the TUDC group than the saline group. Prior to TUDC infusion in the donor animals, there were no differences in BF and BSSR. After infusion of TUDC, BF and BSSR were highly significantly different than the control group. Discussion: Infusion of TUDC in pig livers protects against ischemia/reperfusion injury in vivo. This might be due to the membrane-stabilizing effect of TUDC. Preconditioning of liver grafts with TUDC could potentially lead to improved liver function post-transplantation.
    Materialart: Digitale Medien
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  • 191
    Digitale Medien
    Digitale Medien
    Springer
    Herzschrittmachertherapie & Elektrophysiologie 10 (1999), S. 248-251 
    ISSN: 1435-1544
    Schlagwort(e): Key words Implantable cardioverter defibrillator ; Sudden cardiac death ; Children
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Implantable cardioverter defibrillators (ICDs) are the treatment of choice in adults with symptomatic ventricular tachycardia or aborted sudden cardiac death. Treatment with implantable defibrillators is also possible in children, although experience in this patient group is scanty. A review of the literature on the subject of defibrillator therapy in combination with epicardial electrodes is provided. Endocardial electrodes, which have now become the gold standard in adult treatment, have only rarely been used in children. However, our own experience shows that endocardial electrodes can be implanted in most children, which generally obviates the need for thoracotomy.
    Materialart: Digitale Medien
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  • 192
    Digitale Medien
    Digitale Medien
    Springer
    European archives of oto-rhino-laryngology and head & neck 256 (1999), S. 128-132 
    ISSN: 1434-4726
    Schlagwort(e): Key words Cochlear implant ; Management of ; complications ; Children ; Postoperative care ; Infection ; Device failure ; Reimplantation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In a retrospective analysis we evaluated the intra- and postoperative complications in children who underwent cochlear implantation between 1984 and 1993 at the Medizinische Hochschule Hannover. The data and records of 366 children were collected and analyzed. Relevant parameters were major complications such as significant infection, intraoperative bleeding, facial nerve injury, implant loss and device failure, as well as lesser complications, including delayed wound healing, chronic pain and vertigo. Late complications such as cholesteatoma or electrode dislocations were also registered. Cases of acute otitis media were managed with conservative treatment. Data presented indicate that cochlear implant surgery in children is a reliable and safe procedure with a low percentage of severe complications. Problems related to ear surgery can occur and should be manageable with standard procedures. Careful operative techniques and sufficient personal experience can help avoid severe postoperative problems.
    Materialart: Digitale Medien
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  • 193
    Digitale Medien
    Digitale Medien
    Springer
    European archives of oto-rhino-laryngology and head & neck 256 (1999), S. 442-444 
    ISSN: 1434-4726
    Schlagwort(e): Key words Wheat germ agglutinin-conjugated ; horseradish peroxidase ; Neural regeneration ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Regeneration of the mammalian central vestibular system was examined in rat. The lateral vestibulospinal tract (LVST) of infant rat was transected unilaterally at the level of C1–3. After a postoperative interval of several weeks, the LVST was examined by injecting an anterograde tracer (wheat germ agglutinin-conjugated horseradish peroxidase) into the lateral vestibular nucleus (LVN) and a retrograde tracer (Fast Blue) into the lumbar enlargement. More than half of the rats showed successful regeneration, indicating definite plasticity in the mammalian central vestibular system.
    Materialart: Digitale Medien
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  • 194
    Digitale Medien
    Digitale Medien
    Springer
    European archives of oto-rhino-laryngology and head & neck 256 (1999), S. S8 
    ISSN: 1434-4726
    Schlagwort(e): Key words Cholesteatoma ; Children ; Tympanoplasty
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We studied retrospectively 28 cases of cholesteatoma in children whose ages were 3 to 13 years old. All had undergone surgery between 1989 and 1995. The intact canal wall technique was the predominant method used in the initial operation, with long term goals of an anatomically normal and infection-free ear. Cholesteatoma was found postoperatively in 15 cases and was considered to be residual in 6 cases and recurrent in 9. The residual cholesteatoma was relatively uncommon and usually removable in an exploratory second operation. Our findings showed that the intact canal wall technique was the best initial operation if two-stage surgery was planned. Avoidance of a retraction pocket, which tends to progress to a recurrent cholesteatoma, is important to successful treatment.
    Materialart: Digitale Medien
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  • 195
    Digitale Medien
    Digitale Medien
    Springer
    European archives of oto-rhino-laryngology and head & neck 256 (1999), S. S38 
    ISSN: 1434-4726
    Schlagwort(e): Key words Taste buds ; Cytochalasin D ; Rhodamine-phalloidin ; Confocal laser microscopy ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Effects of cytochalasin D on actin filaments in cells encircling taste pores were examined to clarify the functional role of actin filaments in the maintenance of taste pores in rat fungiform papillae, using a confocal laser microscope and a scanning electron microscope. Fluorescence in the taste pore cells was detected as a ring shape produced by actin staining with rhodamine-phalloidin. Treatment of fungiform papillae with cytochalasin D diminished the positive reactions in the taste pore cells and increased the inner diameter of the ring reactions. However, deformation of the taste pores in fungiform papillae was not detected under a scanning electron microscope after treatment with cytochalasin D. These findings suggest that the organization of actin filaments encircling the taste pores contributes to regulation of the taste pore’s size in rat fungiform papillae.
    Materialart: Digitale Medien
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  • 196
    ISSN: 1573-0603
    Schlagwort(e): Dichloromethylene diphosphate ; Hepatic stellate cell isolation ; Liposome ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Hepatic perisinusoidal cell population consists of hepatic stellate cells, Kupffer cells, endothelial cells, and Pit cells. These cells are isolated by enzymic digestion and purified by density gradient centrifugation. With isolation of stellate cells, conventional method is unable to eliminate the contamination of Kupffer cells because the densities of these two cells are similar. We report here an improved method for isolation of highly purified hepatic stellate cells, using dichloromethylene diphosphate (CL2MDP), which has selective cytotoxicity of Kupffer cells. Three days after the single intravenous administration of liposome-encapsulated CL2MDP, the Kupffer cells disappeared almost completely from the liver. Following Percoll density gradient centrifugation, the purity of the hepatic stellate cells exceeded 98% without any contamination of the Kupffer cells. Kupffer cells are reported to affect the physiological functions of stellate cells. The availability of highly purified stellate cells will facilitate the investigation of their functions in primary culture.
    Materialart: Digitale Medien
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  • 197
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 33 (1999) 
    ISSN: 0009-2851
    Schlagwort(e): Chemistry ; Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 198
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 33 (1999), S. 45-50 
    ISSN: 0009-2851
    Schlagwort(e): Chemistry ; Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A variety of demonstration experiments can be shown to a large audience with a minimum amount of chemicals by using an ordinary slide projector and easily mounted cuvettes. A detailed instruction for assembling the cuvettes is given as m d l as examples for suitable demonstration experiments in general, inorganic, organic and physical chemistry.
    Zusätzliches Material: 21 Ill.
    Materialart: Digitale Medien
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  • 199
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 33 (1999), S. 61-61 
    ISSN: 0009-2851
    Schlagwort(e): Chemistry ; Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 200
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 33 (1999), S. 66-66 
    ISSN: 0009-2851
    Schlagwort(e): Chemistry ; Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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