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  • 1999  (1.757)
  • Chemistry  (1.469)
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  • 1995-1999  (1.757)
  • 1980-1984
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Trauma und Berufskrankheit 1 (1999), S. S92 
    ISSN: 1436-6274
    Schlagwort(e): Schlüsselwörter Wachstumsalter ; MRI ; Beckenfraktur ; Wirbelsäulenfraktur ; Key words Childhood ; Magnetic resonance imaging ; Pelvic fracture ; Spinal injury
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Abstract According to the literature, from 1950 to 1995 the overall risk for children of sustaining a fracture of the spinal column or the pelvic ring doubled, the main reason being the increasing incidence of high-energy trauma caused by newly popular sporting activities such as skateboarding, inline skating and mountain biking. Nonetheless, even specialized pediatric level I trauma centers in Europe and the United States of America report an incidence of below 5% for severe spinal injuries and fractures of the pelvis. Although these specific injury patters are seen relatively infrequently, whenever present they are still highly indicative of high-velocity injury mechanisms, frequently revealing a combination of injuries – each of which would be serious in itself – involving the body cavities and the soft tissues of the trunk an extremities. In summary, spinal cord injuries and pelvic ring fractures are rare but can be serious: cervical and spinal cord injuries without radiological abnormality appear to be more frequent than in adults, and the availability of nuclear magnetic imaging technologies has helped in the diagnosis of unsuspected cord injury in children. In addition, retrospective analysis of purely nonoperative management of highly unstable C-type injuries of the spine and the pelvic ring reveal some unsatisfactory results, so that specifically for these injury morphologies the alternative of an operative strategy might be considered. The purpose of this presentation is to discuss various injury patterns in which an operative concept could be considered, particularly for a multiply injured child.
    Notizen: Zusammenfassung Verletzungen des Rückenmarks und Sprengungen des knöchernen Beckenrings liegen im Kindesalter auch im Krankengut spezialisierter Zentren unter 5%. Besonders beachtenswert erscheint hierbei, daß Rückenmark- und besonders Halswirbelsäulenverletzungen v. a. beim Kind häufig keine ossäre Mitbeteiligung der Wirbelsäule zeigen und erst durch kernspintomographische Diagnostik erfaßt werden können. Desgleichen zeigt sich bei der retrospektiven Auswertung, daß ein pauschales, rein konservatives Management aller Verletzungstypen, d. h. v.a. der sog. C-Verletzungstypen an der Wirbelsäule und am Becken, z. T. unbefriedigende Behandlungsergebnisse zeigt und daher zunehmend bei bestimmten, im weiteren näher besprochenen Verletzungskonstellationen ein eher operatives Grundkonzept diskutiert wird. Neue Erkenntnisse zur Diagnostik und Therapie der Wirbelsäulen- und Beckenverletzung beim Kind liegen insofern vor, als 1. neuere epidemiologische Erhebungen heute eine präzisere, d. h. nicht nur empirisch gesicherte Unterscheidung der selten von eher regelmäßig anzutreffenden Verletzungstypen und Frakturmorphologien erlauben, 2. durch vergleichsweise „neue“ Sportarten wie „Scate-boarding“ und „Mountain-biking“ ganz generell eine statistisch belegte Zunahme von Hochrasanztraumen und komplexen Verletzungsmustern beim Kind beobachtet werden kann sowie 3. generell v.a. beim mehrfachverletzten Kind heute eine eher aggressivere Gangart, d. h. ein in bestimmten Einzelaspekten eher operatives Versorgungskonzept angestrebt wird. Gegenstand der vorliegenden Arbeit sind 1. eine Analyse der als besonders bedeutsam erkannten Verletzungsformen sowie 2. eine Darstellung der heute in Veränderung begriffenen Behandlungskonzepte v.a. beim mehrfachverletzten Kind.
    Materialart: Digitale Medien
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  • 2
    ISSN: 1436-2023
    Schlagwort(e): Key words: hip ; acetabulum ; labrum ; MRI ; radial-sequence
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract: We investigated the usefulness of a radial-sequence magnetic resonance imaging (MRI) technique in the visualization of the acetabular labrum, which surrounds the acetabulum. In 22 hip joints of 12 volunteers, T2-weighted images were obtained on 24 radial planes of the acetabular rim, set at 15°-intervals, using the small tip angle gradient echo method. We examined 7 planes in the weight-bearing portion. The acetabular labrum in the weight-bearing portion was depicted in good contrast to the surrounding tissues. The shape of the labrum differed among individuals and also in the anterior and posterior portions of the labrum. The signal intensity of the labrum was low or partially moderate. There was a high signal intensity band on the base of the acetabular labrum in several portions, which should be carefully interpreted to avoid confusion with abnormality. We concluded that radial-sequence MRI could be a useful technique for evaluation of the condition of the acetabular labrum in the weight-bearing portion.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    European food research and technology 209 (1999), S. 400-406 
    ISSN: 1438-2385
    Schlagwort(e): Key words Pumpkin seed oil ; Oil adulteration ; Δ7-Phytosterols ; Sample clean-up procedure ; Gas chromatography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract  A simple and accurate method for the determination of phytosterols by capillary gas chromatography was developed for the analysis of the seeds and oil of the pumpkin Cucurbita pepo L., the naked seed variety growing in the southern Styrian parts of Austria. After extraction of the oil and saponification, the remaining unsaponifiable material was isolated and purified using silica gel columns. For greater volatility, the sterols were derivatised to trimethylsilylethers, and gas chromatography was performed on a column of high polarity, allowing separation of the Δ5-sterols from the Δ7-sterols and thus yielding a typical chromatographical pattern. Quantification of the phytosterols using 5α-cholestan or cholesterol as internal standards led to a method of high accuracy. Comparison of the chromatographic pattern of the phytosterol fraction of pumpkin seed oil with those of other vegetable oil samples permitted the use of this method to detect adulteration of pumpkin seed oil.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Surgical and radiologic anatomy 20 (1999), S. 413-417 
    ISSN: 1279-8517
    Schlagwort(e): Penis ; Ligaments ; MRI ; Erection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The suspensory system of the penis acquires clinical importance in reparative surgery, traumatology and through its role in erection. The aim of this study was to identify the different anatomic structures constituting the suspensory ligament by dissection and by magnetic resonance imaging (MRI). Ten unembalmed male subjects were used for dissection of the region of the base of the penis. Ten volunteer patients underwent MRI of the penis before and after the injection of prostaglandin (PGE1). The suspensory apparatus consisted of separate ligamentous structures: the fundiform ligament, which is lateral, superficial and not adherent to the tunica albuginea of the corpora cavernosa; the suspensory ligament properly so-called, further back, stretching between the pubis and the tunica albuginea of the corpora cavernosa and consisting of two lateral, circumferential, and one median bundles, which circumscribed the dorsal vein of the penis. These structures were identifiable in MRI and their supporting role was evidenced during tests of erection. The suspensory ligament seemed to maintain the base of the penis in front of the pubis and to behave as a major point of support for the mobile portion of the penis during erection.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Italian journal of neurological sciences 20 (1999), S. 247-249 
    ISSN: 1126-5442
    Schlagwort(e): Key words Superficial siderosis of the central nervous system ; MRI ; Anticoagulant therapy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Superficial siderosis of the central nervous system is a rare condition characterized by deposition of haemosiderin in the leptomeninges and in the subpial layers of the brain and spinal cord. With the widespread use of magnetic resonance imaging, an increasing number of cases of superficial siderosis are being discovered, secondary forms being more frequent than idiopathic ones. We report a 78-year-old man in oral anticoagulant therapy, who presented neurosensory hearing loss, gait ataxia and spastic paraparesis. Magnetic resonance imaging suggested the diagnosis of superficial siderosis of the central nervous system, without an evident bleeding source.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Italian journal of neurological sciences 20 (1999), S. 303-307 
    ISSN: 1126-5442
    Schlagwort(e): Key words Lyme disease ; Chronic neuroborreliosis ; Children ; MRI ; Demyelinating disease
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Lyme disease is a polymorphic and multisystemic disease caused by Borrelia burgdorferi. Neurological manifestations are found in 10%–50% of cases. We present 2 cases followed for 5 and 6 years of chronic relapsing-remitting neuroborreliosis. Diagnosis of neuroborreliosis in these cases was based on serum and cerebrospinal fluid findings. We discuss clinical, neurophysiological, laboratory and instrumental aspects regarding the difficulties of reaching a correct diagnosis. Further studies, especially in the field of immunology, should help identify the mechanisms responsible for the disease becoming chronic. With this knowledge, it may be possible to design immunological therapies for relapses, and to prevent the evolution of the disease.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; RT/PCR ; Protooncogene ; ets-2
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Protooncogenes (PO) play a crucial role for brain biology and pathology. Only the concerted action of protooncogenes enables normal brain development. The reliable and sensitive quantification of brain PO is still holding centre stage in neurobiological research. The aim of our study was therefore the determination of PO in minute amounts of brain areas. For this purpose we decided to apply the most sensitive detection principle of competitive reverse transcriptase polymerase chain reaction using capillary electrophoresis and laser-induced fluorescence detection. We selected the PO ets-2 for our studies as this transcription factor was shown to be involved in neurodegenerative disease. As little as 10ng of total RNA each were extracted from 5 different regions of human postmortem brain and used in the assay system. Our results revealed that the ets-2 gene transcript was detectable at the atto-gram level in the brain (54.5 ± 17.7 ag/ 10 ng RNA in the occipital lobe, 34.2 ± 7.5 in temporal lobe, 40.2 ± 15.6 in the frontal lobe, 31.4 ± 15.7 in the cerebellum, and undetectably low in the parietal lobe). This is the first report at this sensitivity level providing neurobiology with a powerful analytical tool.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 16 (1999), S. 71-77 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Taurine ; Marathon ; Endurance exercise
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The sulphonated amino acid taurine increased significantly in the plasma of trained athletes after three endurance exercises of different duration and intensity, a 90 min run on a treadmill at 75% of an individual's VO2 peak, a Marathon, 42.2km and a 100km run, by 19%, 77% and 36%, respectively. Such results indicated that the speed at which the exercise is per formed, referred to as the intensity, rather than the duration of the exercise, correlated with the elevated taurine levels possibly indicating its release from muscle fibres. The plasma amino acid pool decreased significantly in relationship with the duration of the exercise, caused by their utilisation for glucogenesis. The possible sources of the increased plasma taurine are discussed.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 17 (1999), S. 369-376 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Non-proteinogenic dipeptides ; Dehydrodipeptides ; Diastereoselectivity ; N-Boc-Dehydroamino acids ; Asymmetric hydrogenation ; Chiral rhodium catalysts
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary N-Boc protected non-proteinogenic dipeptides with D,L-and L,L-configuration were prepared by catalytic asymmetric hydrogenation of the corresponding dehydrophenylalanyl-(L)-phenylalanine derivatives. The configuration of the new stereogenic centre depends first of all on the catalyst configuration and is less influenced by the substrate configuration. Diastereomeric excesses in the range of 80–96% de could be increased up to 99% by recrystallization. Analytical data of selected new compounds are given.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Polyclonal antibodies ; Phosalone ; Immunodetection ; Hapten synthesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Hapten synthesis for the production of specific insecticide phosalone polyclonal antibodies was carried out starting from an intermediate of the phosalone synthesis, 6-chloro-2-benzoxazolone1. Two haptens containing different spacers have been prepared: N-5-carboxypentyl-6-chloro-2-benzoxazolone7 and N-(2-oxo-3-aza-5-carboxypentyl)-6-chloro-2-benzoxazolone12. Each of these two haptens conjugated to bovine serum albumine (BSA) was used to immunize four rabbits. Immunoassays of phosalone were performed with ELISA using solid-phase bound hapten thyroglobulin conjugate and horseradish peroxidase labelled goat antirabbit IgG. The more sensitive response was observed when the antiserum obtained from the rabbit immunized with the hapten-BSA conjugate containing the N-2-oxo-3-aza-5-carboxypentyl spacer was in competition with the same hapten coupled to thyroglobulin. An identical response was obtained under the same conditions when using benzoxazolone instead of phosalone as competitor, showing a good recognition of the specific aromatic part of the organophosphate insecticide phosalone. Reduction of coating conjugate concentration (from 2 to 0.05μg/well) and also the use of heterologous coating protein instead of homologous did improve the sensitivity, resulting in a concentration of phosalone required to inhibit binding by 50% of 2 mg/l and a detection limit of 0.02 mg/l.
    Materialart: Digitale Medien
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  • 11
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Liver ; Hepatic damage ; Carbon tetrachloride
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The aims of the present study were to assess the changes of individual plasma amino acid levels in relation (1) to the severity of liver damage and (2) to the process of liver recovery. Acute liver injury was induced by an intragastric administration of CCl4 diluted in olive oil in doses of 2, 4 and /or 6 g of CCl4 per kg b.w. The control rats received olive oil only. Animals were sacrificed at 16, 24, 48 and 96 hours after treatment. The severity of liver injury was assessed by histological examination, by changes in ALT and AST in the blood plasma and by changes in liver weight. Statistical analysis was carried by ANOVA, p 〈 0.05 was considered significant. The Spearman rank correlation coefficient was used as a measure of the degree of linear relationship between variable and dose. In the period of the development of acute liver damage, i.e. at 16 and 24 hours after treatment, an increase in blood plasma amino acid levels and positive correlations with the dose of CCl4 were observed for most individual amino acids. The only exception was arginine which decreased in a dose dependent manner. At a phase of liver recovery, i.e. at 48 and 96 hours after CCl4 treatment, the concentrations of some individual amino acids decreased below the control values. The negative correlation with the dose of CCl4 occurred for taurine and isoleucine (at 48 hours) and taurine, threonine, valine, methionine, isoleucine and leucine (at 96 hours).
    Materialart: Digitale Medien
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  • 12
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Alanine ; Fatty acids ; Glutamine and glutamate synthesis ; Glycerol and lactate metabolism ; Malate-aspartate shuttle ; Rabbit kidney-cortex tubules ; Renal gluconeogenesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In isolated rabbit renal cortical tubules, glucose synthesis from 1 mM alanine is negligible, while the amino acid is metabolized to glutamine and glutamate. The addition of 0.5 mM octanoate plus 2 mM glycerol induces incorporation of [U-14C]Alnine into glucose and decreases glutamine synthesis, whereas oleate and palmitate in the presence of glycerol are less potent than octanoate. Gluconeogenesis is also significantly accelerated when glycerol is substituted by lactate. In view of an increase in14CO2 fixation and elevation of both cytosolic and mitochondrial NADH/NAD+ ratios, the activation of glucose formation from alanine upon the addition of glycerol and octanoate is likely due to (i) stimulation of pyruvate carboxylation, (ii) increased availability of NADH for glyceraldehyde-3-phosphate dehydrogenase and (iii) elevation of mitochondrial redox state causing a diminished provision of ammonium for glutamine synthesis. The induction of gluconeogenesis in the presence of alanine, glycerol and octanoate is not related to cell volume changes. The results presented in this paper show the importance of free fatty acids and glycerol for regulation of renal gluconeogenesis from alanine. The possible physiological significance of the data is discussed.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 16 (1999), S. 79-89 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Anti-neoplastic amino acids ; Purine and DNA synthesis inhibitors ; PRPP amido transferase and IMP dehydrogenase inhibitors
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 4-Hydroxyproline di- and tri-peptides and N-cbz-hydroxypropylglycinamides were observed to be potent cytotoxic agents against the growth of suspended single cells, L-1210, Tmolt3, and HeLa-S3. The agents were not as potent against the growth of cultured solid tumor cells. Selected derivatives were investigated for their mode of action in Tmolt3 leukemia cells. The compounds selectively inhibited DNA synthesis at 50 and 100smM. The target site of action of the agents appeared to be the purinede novo pathway with marked inhibition of the activities of the two regulatory enzymes of the pathway, i.e. PRPP amido-transferase and IMP dehydrogenase. d[NTP] pools were reduced by the agents consistent with their overall reduction of DNA synthesis. Other marginally inhibited targets of the agents were r-RNA polymerase and TMP-kinase activities. The DNA molecule itself did not appear to be a target of these agents.
    Materialart: Digitale Medien
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  • 14
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Targeting ; Mitochondria ; Chloroplasts ; Cysteine synthase ; Transit peptide ; Transgenic plants ; Processing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Cysteme synthase, the key enzyme for fixation of inorganic sulfide, catalyses the formation of cysteine from O-acetylserine and inorganic sulfide. Here we report the cloning of cDNAs encoding cysteine synthase isoforms fromArabidopsis thaliana. The isolated cDNA clones encode for a mitochondrial and a plastidic isoform of cysteine synthase (O-acetylserine (thiol)-lyase, EC 4.2.99.8), designated cysteine synthase C (AtCS-C, CSase C) and B (AtCS-B; CSase B), respectively.AtCS-C andAtCS-B, having lengths of 1569-bp and 1421-bp, respectively, encode polypeptides of 430 amino acids (∼45.8 kD) and of 392 amino acids (∼ 41.8 kD), respectively. The deduced amino acid sequences of the mitochondrial and plastidic isoforms exhibit high homology even with respect to the presequences. The predicted presequence of AtCS-C has a N-terminal extension of 33 amino acids when compared to the plastidic isoform. Northern blot analysis showed thatAtCS-C is higher expressed in roots than in leaves whereas the expression ofAtCS-B is stronger in leaves. Furthermore, gene expression of both genes was enhanced by sulfur limitation which in turn led to an increase in enzyme activity in crude extracts of plants. Expression of theAtCS-B gene is regulated by light. The mitochondrial, plastidic and cytosolic (Hesse and Altmann, 1995) isoforms of cysteine synthase ofArabidopsis are able to complement a cysteine synthasedeficient mutant ofEscherichia coli unable to grow on minimal medium without cysteine, indicating synthesis of functional plant proteins in the bacterium. Two lines of evidence proved thatAtCS-C encodes a mitochondrial form of cysteine synthase; first, import ofin vitro translation products derived from AtCS-C in isolated intact mitochondria and second, Western blot analysis of mitochondria isolated from transgenic tobacco plants expressing AtCS-C cDNA/c-myc DNA fusion protein.
    Materialart: Digitale Medien
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  • 15
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Non-proteinogenic optically active amino acids ; Dehydroamino acids ; Chiral rhodium catalysts ; Asymmetric hydrogenation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary (Z)-α-[(Benzyloxy)- or (tert.-butyloxy)carbonylamino]-β (thienyl)-or (furyl)-acrylic acids and their esters were prepared by known methods and hydrogenated to the corresponding optically active alanine derivatives with optical yields in the range of 58–93% ee using the cationic rhodium complex of “PROPRAPHOS”.
    Materialart: Digitale Medien
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  • 16
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; L-Tryptophan ; Serum albumin ; Transport ; L-Tryptophan depletion ; α-Methyl-DL-tryptophan ; Analbuminemic rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The role of serum albumin in the transport of orally administered L-tryptophan (Trp) into rat tissues was examined using analbuminemic and Sprague-Dawley (SD) rats with and without a-methyl-DL-tryptophan (AMT)-induced Trp depletion. Trp was orally administered to rats 16h after AMT or 0.85% NaCl administration, when liver tryptophan 2,3-dioxygenase and protein synthetic activities in AMT-treated rats were similar to those of 0.85% NaCl-treated rats. After oral Trp administration, regardless of the presence or absence of Trp depletion, free serum Trp concentrations were similar in the analbuminemic and SD rats, while total serum Trp concentrations were lower in analbuminemic rats than in SD rats. Although liver, brain, and muscle Trp concentrations after oral Trp administration under Trp depletion were lower in analbuminemic rats than in SD rats, the ratio of the liver Trp concentration in analbuminemic rats to that in SD rats was smaller than that of the brain or muscle Trp concentration. These results suggest that variations in serum albumin levels could affect the transport of orally administered Trp into the liver of rats with Trp depletion.
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 16 (1999), S. 107-111 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Tissue protein synthesis ; Stable isotope amino acids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The tracers L15N-proline and L(1-13C)-leucine were used to explore the synthesis of skin proteins in vivo in rabbits. They orally received a single dose containing an equimolecular mixture of L(1-13C)-leucine and L15N-proline. The changes in the amounts of these tracers in blood and skin were monitored for a total of 8 h. The data showed the appearance of the two tracers in blood within 15 min and their clearance in 8h. They were both rapidly (15 min) incorporated into skin proteins, but more proline was incorporated than leucine. We therefore consider L15N-proline to be a better tracer than L(1-13C)-leucine for studying protein metabolism in the skin.
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  • 18
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Taurine ; Kainic acid ; Epilepsy ; Anticonvulsants ; Neuroprotection ; Excitatory amino acids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Male Sprague-Dawley rats received TAU supplementation (1.5% in drinking water) or TAU deficient diets for 4 weeks to test for a possible neuroprotective role of TAU in KA-induced (10 mg/kg s.c.) seizures. TAU supplementation significantly increased serum and hippocampal TAU levels, but not TAU content in temporal cortex or striatum. TAU deficient diets did not attenuate serum or tissue TAU levels. Dietary TAU supplementation failed to decrease the number or latency of partial or clonic-tonic seizures or wet dog shakes, whereas a TAU deficient diet decreased the number of clonictonic and partial seizures. This study does not support previous observations of an anticonvulsant effect of TAU against KA-induced seizures. KAtreatment decreasedα 2-adrenergic receptor binding sites and TAU content in the temporal cortex across all dietary treatment groups, supporting previous evidence of severe KA-induced damage and neuronal loss in this brain region.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 16 (1999), S. 191-213 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Enzymatic resolution ; Ester hydrolysis ; Proteases ; Lipases
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The present review outlines recent examples of enzyme-based resolution procedures for amino acids via the hydrolysis of their esters. The resolutions have been achieved by using proteases (α-chymotrypsin, subtilisin and other microbial proteases, and sulfhydryl proteases of plant origin) and lipases. Relevant work utilizing yeast and other microbial cells is also included.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 16 (1999), S. 251-272 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Unusual amino acids ; Aspartic acidβ-semialdehyde ; Aspartaldehyde ; 2-Amino-4-oxobutyric acid ; Enantioselective synthesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Strategies for the synthesis of optically active aspartaldehyde derivatives are reviewed. Most of them are using the chiral pool: allylglycine or naturally occurring homoserine, aspartic acid or methionme and side chain modifications. This will be developed in the first part. Some other original routes are also displayed in the second part. Different aspects of each strategy are discussed: the nature and number of steps, the problem of protecting groups, the price and availability of starting materials. Some synthetic applications of such interesting chiral synthons are shown in the last part.
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  • 21
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Dipeptide derivatives ; Non-proternogenic optically active dipeptide esters ; Dehydrodipeptides ; Chiral rhodium catalysts ; Asymmetric hydrogenation ; Diastereoselectivity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary N-[(Z)-N-Benzoyl- orN-Boc-(2-fluorophenyl)dehydroalanyl]-(R)-or (S)-phenylalanine esters were synthesized and hydrogenated to give the corresponding dipeptide derivatives with optical yields in the range of 53–87%de using the cationic rhodium complexes of PROPRAPHOS and BPPM. The efficiency of chiral diphosphine ligands as well the effect of the chiral center in the substrate on the catalytic asymmetric induction was studied.
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  • 22
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Phytotoxin AS-I analogues ; FAB ; PD ; ESI mass spectrometry ; 1H,13C and 2D NMR
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A series of six tetrapeptides, analogues of AS-I phytotoxin, pathogenic to sunflower, have been synthesized either in solution and/or by solid phase methods and have been tested for phytotoxic activity in various plants and cytotoxic activity in three cancer cell lines. These peptides were identified as model compounds by fast atom bombardment (FAB), plasma desorption (PD), electrospray ionization (ESI) mass spectrometry and by1H,1H-1H,13C and1H-13C NMR. The data presented show that in protected tetrapeptides the molecular ion was easily identified whereas some difficulties appeared with the fully deprotected peptides. NMR spectra are given.
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  • 23
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Diclofenac ; Anti-phlogistics ; Non-proteinogenic amino acids ; Voltaren®. Thionation ; Cyclo-oxygenase inhibitors ; Ulcerogenic gastritis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In search for more potent, particularly less ulcerogenic gastritis that hopefully replace the universal NSAID “Diclofenac”, (2-[(2,6-di-chlorophenyl)amino]-phenylacetic acid, C.A.S. 15307-86-5), twelve new non-proteinogenic amino acid conjugates of the drug, namely that of sarcosine,β-alanine, D-leucine and D-phenylalanine, were synthesized and biologically screened for their anti-inflammatory, analgesic and ulcerogenic activity in rats. “Diclofenac” amino acid esters (IIa-d), were synthesizedvia the corresponding HOSu or HOBt active esters. Alkaline hydrolysis (NaOH) followed by acidification (KHSO4) or thioamide formation (Lawsson's Reagent, C.A.S. 19172-47-5), afforded the corresponding free acids IIIa-d or the thioamides IVa-d respectively. Interestingly, in contrary to the parent “Diclofenac”, the synthesized candidates (except IIId), were entirly nonulcerogenic in rats. Further, they considerably retained a generelized anti-phlogistic activity. The major “Diclofenac” irritating gastric side effect was thus eliminated. Particularly, the sarcosine conjugate IIa and its thiomimic IVa exhibit promising therapeutic perspectives.
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 17 (1999), S. 139-148 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Polyamine oxidase ; Polyamines ; Gender ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Variations in level of polyamines and their related enzymes are frequently observed in response to some treatments which affect in a different way male and female. The possibility of a gender-related difference in the oxidation of polyamines was investigated in rats by measuring the activity of polyamine oxidase, a ubiquitous enzyme of vertebrate tissues, which transforms spermine into spermidine and spermidine into putrescine. The study was carried out on thymus, spleen, kidney and liver of young rats of both sexes, and female rats showed a lower polyamine oxidase activity than male rats in all the tissues. We also found higher values of spermidine acetylation in female than male rats in thymus and liver. Owing to these gender-related differences, a higher spermidine N-acetyltransferase/ polyamine oxidase ratio was found in female than in male rats. A second gender-related difference was a higher spermidine/spermine ratio in female than in male, the only exception being the thymus. These basal differences possibly account for the gender-related differences of polyamine metabolic enzyme activities in response to some treatments, including drugs or hormones.
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 17 (1999), S. 195-205 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Apis mellifera ; Drones ; Osmolarity ; Age dependency
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In the haemolymph of honeybee drones, concentrations of free amino acids were higher than in worker haemolymph, with different relative proportions of individual amino acids. The overall concentration of free amino acids reached its highest level at the 5th day after adult drone emergence, and after the 9th day only minor changes in the concentration and distribution of free amino acids were observed. This coincides with the age when drones reach sexual maturity and change their feeding behaviour. Levels of essential free amino acids were high during the first 3 days of life and thereafter decreased. Osmolarity was lowest at emergence (334 ± 41 mOsm), increased until the age of 3 days (423 ± 32mOsm) and then stayed generally constant until the 16th day of life. Only 25-day-old drones had significantly higher osmolarity (532 ± 38 mOsm). The overall change in osmolarity during a drone's lifetime was about 40%.
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  • 26
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Conformational constraint ; Cyclic disulfides ; -Cys-Cys-peptides ; Dipeptide mimetics ; Dithiols ; Glutathione analogues
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The glutathione analogue γ-(H-Glu-OH)- -OH (5), containing the 8-membered disulfide ring- replacing the native -Cys-Gly fragment, has been synthesized and characterized together with its reduced dithiol form γ-(H-Glu-OH)-Cys-Cys-OH (6).
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  • 27
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Polyamine catabolism ; Polyamine oxidase ; Diamine oxidase ; Testosterone ; Mouse kidney
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In the present study developmental patterns of renal polyamineoxidizing enzymes polyamine oxidase (PAO) and diamine oxidase (DAO) in male and female ICR mice were demonstrated. The effects of testosterone (10μg/100g body weight) on renal PAO and DAO activities were also studied. The differences between sexes in both PAO and DAO activities were most clearly expressed in the immature kidney. At the age of 20 days PAO and DAO activities were 1.52 fold (p 〈 0.01) and 1.75 (p 〈 0.02) respectively higher in male mouse kidney than in female. Maturational processes reflected in significant increases in polyamine- oxidizing enzyme activities mainly in female mouse kidney, comparable with the gain in the kidney wet weight. Our data show that testosterone is able to influence renal PAO and DAO activities in addition to the well-known stimulation of polyamine biosynthesis. The hormonal effects were sex and age dependent. The influence of testosterone on renal PAO activity was mainly age dependent. The slight stimulation of renal PAO activity observed in 20- and 50-day old mice, 24h after testosterone administration, change with a decrease in the enzyme activity at the age of 70 days. The effects of testosterone on renal DAO activity were mainly sex dependent. Testosterone caused stimulation of DAO activity with a very close magnitude (nearly twice) in female mouse kidney, independently of the age of mice. In contrast, in male mice the hormone treatment resulted in a statistically significant increase in renal DAO activity at the age of 70 days (.1.3 fold, p 〈 0.05) only. It could be suggested that our data indicate the different contribution of renal PAO and DAO in androgen regulation of polyamine levels, depending on sex and the stage of the postnatal development.
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  • 28
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Allohydroxyproline ; Allothreonine ; Chiral separation ; Chirasil-Val ; Hydroxyproline ; Threonine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Experimental conditions for the derivatization and resolution by GLC of all stereoisomers of threonine and 4-hydroxyproline are reported. Threonine was in two steps converted toN,O-bisisobutoxycarbonyl 2,2,2-trifluoroethyl ester derivatives, the second of which was performed under anhydrous conditions. As such the enantiomers could pairwise be separated by capillary gas chromatography on a Chirasil-Val column. SinceL- andD-threonine eluted much earlier than the corresponding allo forms, quantitative determination of the allothreonine content inD- orL-threonine down to the one percent level could be simply accomplished but also enantiomeric impurities could be determined. Unlike for threonine, the corresponding 4-hydroxyproline isomers could not all be resolved asN,O-bisisobutoxycarbonyl 2,2,2-trifluoroethyl esters on this column. Although diastereomers could still be separated, the allo pair cochromatographed and the resolution for theL- andD-isomers was low. Complete separation of the 4-hydroxyproline isomers could be accomplished asN,O-bisprotected isobutyl amides, the formation of which required three derivatization steps. These were used for the determination of allohydroxyproline.
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 17 (1999), S. 323-334 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Taurine release ; Cerebellar granule cells ; Celldamaging conditions ; Glutamate receptors ; Veratridine ; Potassium stimulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The release of taurine from cultured cerebellar granule neurons was studied in different cell-damaging conditions, including hypoxia, hypoglycemia, ischemia, oxidative stress and in the presence of free radicals. The effects of both ionotropic and metabotropic glutamate receptor agonists on the release were likewise investigated. The release of [3H]taurine from the glutamatergic granule cells was increased by K+ (50mM) and veratridine (0.1 mM), the effect of veratridine being the greater. Hypoxia and ischemia produced an initial increase in release compared to normoxia but resulted in a diminished response to K. Hypoglycemia, oxidative stress and free radicals enhanced taurine release, and subsequent K− treatment exhibited a correspondingly greater stimulation. A common feature of taurine release in all the bove conditions was a slow response to the stimulus evoked by K+ and particularly to that evoked by veratridine. All ionotropic glutamate receptor agonists potentiated taurine release, but only the action of kainate seemed to be receptor-mediated. Metabotropic receptor agonists of group I slightly stimulated the release. The prolonged taurine release seen in both normoxia and cell-damaging conditions may be of importance in maintaining homeostasis in the cerebellum and reducing excitability for a longer period than other neuroprotective mechanisms.
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  • 30
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Taurine ; Osmoregulation ; Rat ; Osmolarity sensor protein ENVZ
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Although the involvement of taurine in osmoregulation is well-documented and widely accepted, no detailed mechanism for this function has been reported so far. We used subtractive hybridization to study mRNA steady state levels of genes up- or downregulated by taurine. Rats were fed taurine 100mg/kg body weight per day for a period of three days and hearts (total ventricular tissue) of experimental animals and controls were pooled and used for mRNA extraction. mRNAs from two groups were used for subtractive hybridization. Clones of the subtractive library were sequenced and the obtained sequences were identified by gen bank assignment. Two clones were found to contain sequences which could be assigned to the osmolarity sensor protein envZ, showing homologies of 61 and 65%. EnvZ is an inner membrane protein in bacteria, important for osmosensing and required for porine gene regulation. It undergoes autophosphorylation and subsequently phosphorylates OmpR, which in turn binds to the porin (outer membrane protein) promoters to regulate the expression of OmpF and OmpC, major outer membrane porines. This is the first report of an osmosensing mechanism in the mammalian system, which was described in bacteria only. Furthermore, we are assigning a tentative role for taurine in the osmoregulatory process by modifying the expression of the osmoregulatory sensor protein ENVZ.
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  • 31
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Protein ; arginine methyltransferase ; Inhibitors ; Ginseng extract ; Arginine derivatives ; Basic amino acids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Protein-arginine N-methyltransferase (protein methylase I) catalyzes methylation of arginyl residues on substrate protein posttranslationally utilizing S-adenosyl-L-methionine as the methyl donor and yields NG-methylarginine residues. Arginyl-fructose and arginyl-fructosyl-glucose from Korean red ginseng were found to inhibit protein methylase I activity in vitro. This inhibitory activity was shown to be due to arginyl moiety in the molecules, rather than that of carbohydrates. Several basic amino acids as well as polyamines were also found to inhibit protein methylase I activity. Interestingly, the intensity of the inhibitory activity was correlated with the number of amino-group in polyamines, thus, in the order of spermine 〉 spermidine 〉 putrescine 〉 agmatine-sulfate, with IC50 at approximately 15 mM, 25 mM, 35 mM, and 50 mM, respectively. On the other hand, neutral amino acids or NaCI did not inhibit the enzyme activity. Lineweaver-Burk plot analysis of the protein methylase I activity in the presence of arginine and spermidine indicated that the inhibition was competitive in nature in respect to protein substrate, with the Ki values of 24.8 mM and 11.5 mM, respectively.
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  • 32
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Hexafluoroacetone ; α-N-Methylamino acids ; α-N-Phosphinoylmethylamino acids ; Pro-Glu-chimeras ; Pro-Tauchimeras
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A new method for the preparation of N-methylamino acids and some of their derivatives starting from hexafluoroacetone protected amino acids is described. The new concept results in saving of steps compared to conventional protection/activation techniques. Protection and deprotection proceed without racemization.
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  • 33
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Perfluorinated compounds ; Surfactants ; Complexing properties ; Carnosine ; β ; Amino acids ; Blood substitutes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The reaction of amines or sodium azide with 3-perfluoroalkyl-3-fluoroprop-2-enoate, followed by hydrogenation, affords perfluoroalkylatedβ-alanine analogues in very good yields. These compounds can be linked via an amide bond to produce peptide analogues such as carnosine or carcinine derivatives, which could have surfactive and complexing properties.
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 16 (1999), S. 415-423 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; SOD-like activity ; Cu (III)-Poly-L-lysine ; Cu(III)-Poly-L-glutamic acid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The SOD-like activity of Cu(III) -complexes with polypeptides poly-L-lysine and poly-L-glutamic acid respectively was investigated. The Cu(II)-polypeptide complexes were first oxidized by K2IrCl6 to give the corresponding Cu(III) -compounds. The oxidation of Cu(II) and the corresponding Cu(II)/Cu(III) potential was evaluated by cyclic voltammetry (c.v.), UV-Vis and EPR spectroscopic (r.t.) experiments. Spin trapping EPR spectra were also conducted to confirm the formation of the superoxide radical. The SOD-like activity of each Cu(III)-complex was proved using the nitro blue tetrazolium (NBT) method slightly modified.
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  • 35
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Lysine ; Herbicides ; Azotobacter ; Xenobiotics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Production of lysine byAzotobacter chroococcum strain H23 was studied in chemically-defined media amended with different concentrations of alachlor, metolachlor, 2,4-D, 2,4,5-T and 2,3,6-TBA. The presence of 5, 10, and 50μg/ml of alachlor or 2,3,6-TBA significantly decreased quantitative production of lysine. However, the presence 2,4-D or 2,4,5-T at concentrations of 10 and 50μg/ml enhanced the production of lysine. Quantitative production of lysine was not affected as consequence of the addition of metolachlor to the culture medium, showing that the release lysine to the culture media byA. chroococcum was not affected by that herbicide.
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  • 36
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Trypanothione ; Glutathione ; Benzyloxycarbonyl-reductase ; Hydrocinnamoyl
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Kinetic data for alternative substrates of recombinant trypanothione reductase fromTrypanosoma cruzi were measured for a series ofN-substituted-L-cysteinylglycyl-3-dimethylaminopropylamides, in which the cysteineN-substituent was either a variant of the benzyloxycarbonyl group or was L-phenylalanine or L-tryptophan. Replacing the benzylic ether oxygen atom by CH2. or NH had relatively minor effects on kcat, but raised the value of Km, 4.5- and 10-fold, respectively. Similarly, relative to the carbobenzoxy group, anN-L-phenylalanyl orN-L-tryptophanyl replacement on the cysteine hardly altered kcat, but increased Km, values by 16.6 and 7.4 fold, respectively. These observations were consistent with the Km, values referring primarily to binding for this series of nonspecific substrates.
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 17 (1999), S. 243-255 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Serotonin receptor ; Serotonin-3 receptor ; Ion channel ; Ion permeability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Human 5-HT3 receptors expressed in HEK 293 cells were studied using patch-clamp techniques. The permeability ratios of cations to Na+ were Li+, 1.16; K+, 1.04; Rb+, 1.11; Cs+ 1.11; NMDG+, 0.04; Ca2+, 0.49, and Mg2+, 0.37. The permeability sequence of the alkali metal cations was Li+ 〉 Rb+ = Cs+ 〉 K+ 〉 Na+. Increased external concentrations of Ca2+ or Mg2+ decreased 5-HT-induced currents at all potentials tested in a voltage-independent manner. The single-channel conductance of human 5-HT3 receptors measured by fluctuation analysis of whole-cell currents was 790 ± 100fS. Differences in the basic properties of 5-HT3 receptors between species may explain interspecies differences in pharmacological properties.
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 17 (1999), S. 301-313 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Taurine ; Transporter ; Rat ; Brain ; Heart
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In pro- and eucaryotic life, cellular and subcellular compartments are separated by membranes and the regulated and selective passage of specific molecules across these membranes is a basic and highly conserved principle. We were interested whether taurine, a naturally occuring amino acid, would be able to induce or suppress expression of transporters with the Rationale that taurine was shown to detoxify a series of endogenous toxins and xenobiotics of various chemically non-related structures. For this purpose we used a gene hunting technique, subtractive hybridization, subtracting mRNAs of taurine-treated rat brain and heart from untreated controls. Subtracted mRNAs were then converted to cDNAs, amplified, sequenced and identified by gene bank data. We found five transporter transcripts, the phosphonate transport ATPase PHNC, multidrug transporter homolog MTH104, protein-exportmembrane protein SECD, oligopeptide transporters oppA and oppD, in the brain and two: ABC-transporter BRAF-2 and cation-transport ATPase PACS, in the heart. Homologies of the sequences found were in any case 〉50% thus permitting the identification of transporters with high probability. The biological meaning could be that a naturally occuring amino acid, taurine, modulates complex transport systems. The most prominent finding is the upregulation of a multidrug transporter transcript, explaining a mechanism for the nonselective detoxifying action of taurine.
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  • 39
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Tyrosine ; Phenylalanine ; Aromatic compounds ; Rumen microorganisms[/klw]
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Rumen contents from three fistulated Japanese native goats fed Lucerne hay cubes (Medicago sativa) and concentrate mixture were collected to prepare the suspensions of mixed rumen bacteria (B), mixed protozoa (P) and a combination of the two (BP). Microbial suspensions were anaerobically incubated at 39°C for 12h with or without 1 MM ofl-phenylalanine (Phe). Phe, tyrosine (Tyr) and other related compounds in both supernatant and microbial hydrolysates of the incubations were analyzed by HPLC. Tyr can be produced from Phe not only by rumen bacteria but also by rumen protozoa. The production of Tyr during 12h incubation in B (183.6 μmol/g MN) was 4.3 times higher than that in P. One of the intermediate products between Phe and Tyr seems to bep-hydroxyphenylacetic acid. The rate of the net degradation of Phe incubation in B (76.O μmol/g MN/h) was 2.4 times higher than in P. In the case of all rumen microorganisms, degraded Phe was mainly (〉53%) converted into phenylacetic acid. The production of benzoic acid was higher in P than in B suspensions. Small amount of phenylpyruvic acid was produced from Phe by both rumen bacteria and protozoa, but phenylpropionic acid and phenyllactic acid were produced only by rumen bacteria.
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 17 (1999), S. 357-368 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; o-Carboranylalanine ; Histidine ; Bacteria ; Fungi ; Oomycota ; Plasmopara
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Functionalized polyhedral carboranes, including amino acid analogs, have unique physicochemical properties and are used as experimental anticancer agents. However, our current knowledge on their effect in nonmammalian biological systems is limited. We investigated the activity spectrumin vitro ofo-carboranylalanine (o-Cba), considered to be a highly lipophilic analog of phenylalanine, against representative plant pathogenic bacteria and fungi of various taxonomic position. The antibacterial effect ofo-Cba against some species was comparable to that of the widely used agricultural antibiotic, streptomycin. The sensitivity of individual bacterial species too-Cba within the same genus varied to a greater extent than the average sensitivity of various genera. In general, this carborane-containing amino acid was more toxic to Gram positive bacteria (Bacillus, Corynebacterium, Curtobacterium, Micrococcus, Rhodococcus, and Staphylococcus) than to Gram negative ones (Agrobacterium, Erwinia, Escherichia, Pseudomonas, Rhizobium, and Xanthomonas). Compared to the commercial fungicide, prochloraz,o-Cba was weakly toxic against various fungi (Zygo- and Ascomycota). It was also inferior to the commercial fungicide metalaxyl in inhibiting the vegetative growth of oomyceteous plant pathogens (Pythium irregulare, Phytophthora cryptogea and Plasmopara halstedii). Against the asexual spores of P. halstedii,o-Cba, however, was over a thousandfold more active than tridemorph, a selective zoospore inhibitor fungicide. For all taxonomic groups, the observed antimicrobial effect ofo-Cba could be diminished with histidine, but not with phenylalanine. In studies on healthy and mildew-infected sunflower and tobacco plantso-Cba showed neither fungicidal nor phytotoxic effects at 500ppm. This is the first report on the biological activity spectrum of a carborane-containing amino acid.
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 17 (1999), S. 401-413 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Indolylacrylic acid ; Tryptophan ; Indolylacryloylglycine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In addition to the main catabolic routes of tryptophan (Trp), there exist minor and less thoroughly investigated pathways; one of these leads to indolylacrylic acid (IAcrA). IAcrA is a plant growth hormone, whereas its biological role in animals is still obscure, as is the way and site where it is formed in the organism. A two-stage production is likely: Intestinal microorganisms catabolize Trp to indole derivatives which are then absorbed and converted to IAcrA and its glycine conjugate, indolylacryloylglyeine (IAcrGly). Our finding of IAcrGly in the urine of proven germ-free piglets points to the possibility that Trp can be converted to IAcrA without the intervention of intestinal microorganisms. Seasonal and age variations, influence of light and connection with photodermatoses have been reported. Besides other pathological conditions the differences in IAcrGly excretion relative to normal controls were especially pronounced in some myopathies, namely in boys with Duchenne muscular dystrophy.
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  • 42
    ISSN: 1432-1912
    Schlagwort(e): Key words Asphyxia ; Nitric oxide ; Electron spin ; resonance ; Adrenocorticotropin ; Resuscitation ; S-Methylisothiourea ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Anaesthetized rats, endotracheally intubated and mechanically ventilated with room air, were subjected to a 5-min period of asphyxia by turning off the ventilator. The ventilator was then turned back on and, simultaneously, the animals were treated with either the adrenocorticotropin fragment 1–24 [ACTH-(1–24), 160 µg/kg in a volume of 1 ml/kg i.v.] or an equivalent volume of saline. Nitric oxide (NO)-haemoglobin formation was detected ex vivo in arterial blood by electron spin resonance spectrometry; arterial blood pressure, electrocardiogram (ECG) and electroencephalogram (EEG) were monitored for a 60-min observation period, or until prior death. During asphyxia, there was massive formation of NO (red cell concentrations 40–80 µM), associated with a dramatic fall in mean arterial pressure and pulse pressure, marked bradycardia and ECG signs of ischaemic damage, as well as an isoelectric EEG. Treatment with ACTH-(1–24) produced a prompt (within 15 min) and long-lasting drop in NO blood levels, associated with an almost immediate (within 1 min) restoration of cardiovascular function and with a more gradual recovery of EEG, which became normal after 30–40 min; all parameters remained stable throughout the 60-min observation period. In saline-treated rats, on the other hand, there was a further increase in NO blood levels, as detected 3 min after treatment, and all died within 5–8 min. Moreover, pretreatment and treatment with S-methylisothiourea sulphate (SMT, 3 mg/kg i.v.), a relatively specific inhibitor of inducible NO synthase, inhibited NO formation, but did not affect the mortality rate (100% within 5–8 min). The present results provide the first evidence that prolonged asphyxia is associated with high blood concentrations of NO, and that the life-saving effect of melanocortin peptides in severe hypoxic conditions is associated with a complete normalization of NO blood levels. However, the lack of SMT protection in this experimental model seems to rule out the possibility that the ACTH-(1–24)-induced resuscitation is due to an effect on NO overproduction.
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 359 (1999), S. 117-122 
    ISSN: 1432-1912
    Schlagwort(e): Key words Ethanol ; Restraint stress ; NMDA receptor complex ; Memantine ; Drug discrimination ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract There is a large body of experimental evidence that both stress and N-methyl-d-aspartate (NMDA) receptor antagonists may alter acute behavioural effects of ethanol. Notably, an uncompetitive, low-affinity NMDA receptor antagonist, memantine, has been recently claimed to possess anti-craving properties in rats with a long-term history of ethanol consumption. The aim of the present study was to assess the effects of restraint stress and memantine on the dose-response curve of ethanol discrimination. Rats were trained to discriminate 1 g/kg ethanol from saline in the two-lever drug discrimination procedure. When ethanol discrimination was acquired, the subjects were exposed to 30-min sessions of acute restraint stress, and different doses of ethanol (0.25, 0.5 or 1 g/kg) or saline were administered. In subsequent experiments the effects of memantine (2.25 or 4.5 mg/kg) on the cueing effects of ethanol were tested. Neither the stress sessions nor memantine influenced the ethanol discrimination dose-response curve. Moreover, the stress did not alter the rate of responding. However, both doses of memantine tended to increase the rate of responding when given in combination with lower doses of ethanol (0.25–0.5 g/kg). In contrast, 4.5 mg/kg memantine decreased the response rate when combined with 1 g/kg ethanol. These results suggest that: (1) pre-exposure to acute restraint stress or memantine does not affect the dose-response curve of ethanol discrimination; (2) memantine given in combination with low doses of ethanol may stimulate operant behaviour in the food-reinforced drug discrimination procedure.
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 29 (1999), S. 257-261 
    ISSN: 1432-0789
    Schlagwort(e): Key words Alpine nitrogen cycle ; Amino acids ; Kobresia myosuroides ; Organic nitrogen ; Plant-microbe competition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract  Microbes are assumed to possess strong competitive advantages over plants for uptake of nutrients from the soil. The finding that non-mycorrhizal plants can obtain a significant fraction of their N requirement from soil amino acids contradicts this assumption. The amino acid glycine (Gly) has been used as a model amino acid in many recent studies. Our preliminary studies showed that Gly was a poor substrate for microbial growth compared to other amino acids. We tested the hypothesis that the alpine sedge Kobresia myosuroides competes better for Gly than for other amino acids because of decreased microbial demand for this compound. Soil microbial populations that could grow using Gly as a sole carbon source were about 5 times lower than those that could grow on glutamate (Glu). Gly supported a significantly lower population than any of the ten other amino acids tested except serine. In contrast, K. myosuroides took up Gly from hydroponic solution at faster rates than Glu. In plant-soil microcosms, plants competed with soil microbes 3.25 times better for Gly than for Glu. We conclude that the low microbial demand and the rapid plant uptake of Gly relative to other amino acids allow Gly to be an especially important nitrogen source for K. myosuroides.
    Materialart: Digitale Medien
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  • 45
    ISSN: 1432-0975
    Schlagwort(e): Key words Otolith ; Chemistry ; ICP-MS ; Stock discrimination ; Epinephelus striatus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie
    Notizen: Abstract  We examined the utility of otolith minor and trace element chemistry, assayed with inductively coupled plasma mass spectrometry (ICP-MS), as a means of delineating population structure in the Nassau grouper (Epinephelus striatus). We characterized the elemental composition of otoliths collected in 1993 from three locations in Exuma Sound, Bahamas and from Glover Reef, Belize in 1995. A single location in Exuma Sound was sampled in 1994 to test temporal variability in otolith composition. Five elements (Ca, Zn, Sr, Ba and Pb) were routinely detected, at levels significantly above background, by solution-based ICP-MS. Results from analysis of variance of elemental data, expressed as a ratio to Ca, indicated that there were no significant differences among the Exuma locations for any element, but significant variability was found between Glover Reef and the pooled Exuma localities for Zn/Ca, Sr/Ca and Ba/Ca ratios. Significant inter-annual differences at one Exuma Sound location was restricted to Ba/Ca ratios. Discriminant function analysis correctly classified 86% and 95% of the Belize and pooled Exuma sites, respectively. Otoliths from Belize were characterized by low Zn/Ca and high Ba/Ca and Pb/Ca ratios compared to otoliths from fish collected in Exuma Sound. Although differences in Ba levels may be related to upwelling at Glover Reef, more data are needed to definitely link otolith composition with regional differences in water chemistry.
    Materialart: Digitale Medien
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  • 46
    ISSN: 1433-0407
    Schlagwort(e): Schlüsselwörter Hallervorden-Spatz-Krankheit (HSD) ; präsenile Demenz ; MRT ; paramagnetische Substanzen ; Globus pallidus ; Key words Hallervorden-Spatz-Disease (HSD) ; Early onset dementia ; MRI ; Paramagnetic substances ; Globus pallidus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary We report the history of a 38 year old patient who began to develop mental deterioration at the age of 26. After a time of 7 years neurological signs like writing dystonia occured. Hallervorden-Spatz-Desease (HSD) was diagnosed at the age of 36 in vivo with the clinical presentation of severe dystonia, rigidity, dementia, and typical signal loss in the globus-pallidus the reticular part of the substantia nigra, and the nucleus ruber in the T-2 weighted MRI. The „eye-of-the-tiger”-sign, a bilateral hyperintensity in the rostral globus pallidus, was not observed in follow-up examinations. HSD is a rare autosomal-recessive or sporadic disease of unknown etiology. In one third of the patients a dementing process is the first clinical sign of the disorder, and is a rare differential diagnosis of early onset dementia.
    Notizen: Zusammenfassung Wir berichten von einem 38jährigen Patienten, der im Alter von 26 Jahren eine progressive Demenz entwickelte. Erst nach einem Krankheitsverlauf von 7 Jahren kam es zur Manifestation eines rasch progredienten, dystonen Syndroms bis hin zur Immobilität im Alter von 36 Jahren. Die Diagnose der Hallervorden-Spatz-Erkrankung (HSD) wurde aufgrund des klinischen Bildes im Spätstadium der Erkrankung mit schwerster Demenz, Dystonie und Rigidität in Zusammenschau mit den typischen Signalauslöschungen in der T2-gewichteten MRT im Globus pallidus, dem Nucleus ruber und dem retikulären Anteil der Substantia nigra gestellt. Das „Eye-of-the-tiger”-Zeichen, eine bilaterale Signalhyperintensität im rostralen Anteil des Globus pallidus, wurde, auch bei Verlaufsuntersuchungen, nicht gefunden. Die Hallervorden-Spatz-Erkrankung ist ein autosomal-rezessiv oder sporadisch auftretendes Krankheitsbild ungeklärter Ätiologie. Da sich bei einem Drittel der Patienten mnestische Störungen im Kurz- und Langzeitgedächnis als Erstsymptom manifestieren, stellt die HSD eine seltene Differentialdiagnose eines präsenilen Demenzsyndroms dar. In der diagnostischen Beurteilung kommt der Magnetresonanztomographie eine wesentliche Bedeutung zu.
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Der Nervenarzt 70 (1999), S. 276-280 
    ISSN: 1433-0407
    Schlagwort(e): Schlüsselwörter Metachromatische Leukodystrophie ; Totschlag ; Hebephrenie ; MRT ; Diagnose ; Key words Metachromatic leukodystrophy ; Homicide ; Hebephrenia ; MRI ; Diagnosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary We report a patient with metachromatic leukodystrophy (MLD) with a first manifestation of homicide. On admission the patient showed a hebephrenia-like syndrom with inappropriate affect, thought disorder and behavioral changes. Magnetic resonance tomography (MRT) findings suggested a diagnosis of MLD, which was confirmed by a decreased activity of leucocyte arylsulfatase A and an excessive urinary sulfatide excretion.
    Notizen: Zusammenfassung Wir berichten von einem Patienten mit metachromatischer Leukodystrophie (MLD), der im Alter von 16 Jahren ein Kind tötete. Bei der klinischen Untersuchung zeigte er ein hebephrenes Syndrom mit veränderter Affektivität, formalen Denkstörungen und Verhaltensauffälligkeiten. Bei der neuropsychologischen Testung wurde eine starke Beeinträchtigung von Planen und Problemlösen bei insgesamt überdurchschnittlicher Intelligenz nachgewiesen. Die neurologischen und internistischen Befunde waren unauffällig. Anhaltspunkte für eine MLD fanden sich im Magnetresonanztomogramm (MRT) und wurden biochemisch bestätigt.
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  • 48
    ISSN: 1433-0407
    Schlagwort(e): Schlüsselwörter Septum pellucidum ; Entwicklungs- störungen ; Zerebrale Fehlbildungen ; Schizophrenie ; Magnetresonanztomographie ; Key words Septum pellucidum ; Developmental disorder ; Cerebral malformations ; Schizophrenia ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Absence of the septum pellucidum is a rare developmental disorder of the human brain. Previous reports focused on the association with other cerebral anomalies. We present MRI scans showing an isolated absence of the septum pellucidum. The patient was suffering from a schizophrenic psychosis. Mental retardation or epileptic seizures, which are often found in more complex developmental brain disorders, were not observed. The septal area is part of the limbic system and aplasia of the septum pellucidum could indicate developmental anomalies of the limbic system. The concept of cerebral maldevelopment and the limbic system in schizophrenic psychosis is discussed.
    Notizen: Zusammenfassung Die isolierte Aplasie des Septum pellucidum gehört zu den seltenen dysplastischen Fehlbildungen des Gehirns. Während in älteren Arbeiten das Fehlen des Septum pellucidum meistens im Zusammenhang mit weiteren zerebralen Fehlbildungen berichtet wird, so zeigen neuere Untersuchungen doch häufiger auch isolierte Aplasien ohne weitere Fehlbildungen des Gehirns. Dabei scheint ein breites Spektrum der Fehlbildungen von komplexen Hirnfehlbildungen bis hin zur einfachen Aplasie des Septum pellucidum zu reichen. Kasuistisch wird über die Aplasie des Septum pellucidum bei einem Patienten berichtet, welche kernspintomographisch im Rahmen der routinemäßig durchgeführten bildgebenden Diagnostik gefunden wurde. Klinisch wurde bei dem Patienten eine hebephrene Psychose diagnostiziert. In der Ätiologie der schizophrenen Psychosen werden dysontongenetische Mechanismen diskutiert, v.a. Migrationsstörungen in limbischen Strukturen. Eine erhöhte Inzidenz von Anomalien des Septum pellucidum, v.a. Septum-pellucidum-Zysten ist von mehreren Autoren bei schizophrenen Patienten berichtet worden. Die Bedeutung des Septum pellucidum und des Septum verum als Bestandteile des limbischen Systems werden erörtert und eine mögliche Relevanz für das Konzept der dysontogenetischen Ätiologie schizophrener Psychosen wird diskutiert.
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    International journal of legal medicine 112 (1999), S. 124-131 
    ISSN: 1437-1596
    Schlagwort(e): Key words Hydroxyproline ; D/L Aspartic acid ; N-TFA isopropyl ester derivatives ; Gas chromatography ; Collagen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Rechtswissenschaft
    Notizen: Abstract The proportion of D- to L-enantiomers of aspartic acid in metabolically isolated proteins has been used by forensic scientists to estimate age at death. We have demonstrated the interference of a derivative of hydroxyproline (N-TFA isopropyl Hyp ester) with the N-TFA isopropyl L-Aspartic (Asp) acid ester during gas chromatography of amino acids. This has serious implications for the accurate quantification of the D- to L-Asp ratio extracted from collagenous proteins. Having demonstrated the potential for this co-elution in amino acid standards, acid-soluble dentine proteins and non-mineralised collagen, we argue that this problem can be overcome either by high resolution separation or by analysis of the (Hyp-poor) non-collagenous protein fraction.
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  • 50
    ISSN: 1437-7799
    Schlagwort(e): Key words Desferrioxamine ; Cadmium ; Metallothionein ; Nephrotoxicity ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background. Desferrioxamine (DFO) a chelating agent, is used to treat metal toxicity caused by iron and aluminum in patients on hemodialysis. We hypothesized that DFO could also be used to treat cadrium-induced nephropathy. Animal experiments were therefore performed to explore whether DFO removed cadmium (Cd) from the kidneys of rats with a Cd burden. Methods. Rats received subcutaneous injections of Cd chloride (3 mg Cd/kg per day, days 0–7) followed by DFO (50 mg/kg per day, days 8–14). Levels of Cd were determined in liver, kidneys, and plasma. Enzymes assays and histopathological examination were performed in kidneys. Results. In liver, Cd injections elevated Cd levels; subsequent injections of DFO lowered the Cd levels compared with levels after injections of Cd alone. In kidneys, Cd injections increased levels of total Cd and Cd bound to cellular membranes (Mem-Cd), and decreased leucine aminopeptidase (LAP) activity (a marker of renal injury); subsequent injections of DFO elevated levels of total Cd and Mem-Cd, and lowered LAP activity compared with fundings after the injection of Cd alone. After the injections of Cd alone and DFO following Cd the renal levels of Cd were below the critical concentration required to cause renal injury, since no histopathological changes were observed in the kidney. Conclusion. DFO administration to Cd-burdened rats removed Cd from the liver, but led to accumulation of Cd in the kidneys, particularly in the cellular membranes. These results suggest that if DFO is given long-term to Cd-burdened patients, the Cd level in kidneys, particularly in renal cellular membranes, could reach concentrations that could cause manifest renal injury.
    Materialart: Digitale Medien
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  • 51
    ISSN: 1437-9813
    Schlagwort(e): Key words Congenital diaphragmatic hernia ; Rat ; Glucocorticoid ; Antenatal therapy ; Insulin-like growth factor I and II ; Reverse transcription-polymerase chain reaction (RT-PCR)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract There is increasing evidence to suggest that insulin-like growth factors (IGF) I and II play a crucial role in fetal lung development. Expression of IGF-I and II has been demonstrated to be predominant during fetal life and decreases prior to birth. Antenatal glucocorticoids are reported to improve lung immaturity. The aim of this study was to investigate the effect of antenatal glucocorticoid administration on IGF-I and II expression in nitrofen-induced congenital diaphragmatic hernia (CDH) in rats. A CDH model was induced in pregnant rats following administration of 100 mg nitrofen on day 9.5 of gestation (term = 22 days). Dexamethasone (0.25 mg/kg) was given intraperitoneally on days 18.5 and 19.5 of gestation. Cesarean section was performed on day 21. The fetuses were divided into three groups: I, normal controls; II, nitrofen-induced CDH; and III, nitrogen-induced CDH with antenatal dexamethasone treatment. mRNA was extracted from whole lung and a reverse transcription-polymerase chain reaction (RT-PCR) was performed to evaluate the relative amounts of IGF I and II mRNA. Levels of mRNA were expressed as a ratio of the band density divided by that of β-actin, a housekeeping gene known to be expressed at a constant level. Immunohistochemistry using anti-rat IGF I and II antibody was also performed in each group. Levels of IGF I mRNA were significantly increased in group II (0.50 ± 0.08) compared to group I (0.34 ± 0.10) or group III (0.32 ± 0.06) (P 〈 0.05). Levels of IGF II mRNA were also significantly increased in group II (0.95 ± 0.20) compared to group I (0.42 ± 0.07) or group III (0.31 ± 0.09) (P 〈 0.05). Strong IGF I and II expression was observed in the hypoplastic CDH lung (group II), mainly in the bronchiolar epithelium. IGF I and II expression in group I and III lungs was either absent or weak. The finding of significant reductions in IGF I and II mRNA and protein levels in dexamethasone-treated CDH lung suggest that dexamethasone may accelerate the fetal stage of lung development.
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Pediatric surgery international 15 (1999), S. 201-205 
    ISSN: 1437-9813
    Schlagwort(e): Key words Esophagus ; Atresia ; Notochord ; Adriamycin ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Esophageal atresia (EA) is often accompanied by vertebral defects and other anomalies. The adriamycin rat model of EA has disclosed the embryology of the malformation and shown that the vertebrae and notochord are also abnormal. This study describes the nature of notochord malformations in rat embryos exposed to adriamycin. Time-mated rats received either 1.75 mg/kg adriamycin or vehicle i.p. on gestational days (E) 6 to 9; E-12, E-12.5, and E-13 embryos were harvested, embedded in paraffin, and serially sectioned at 3 μm in transverse plane from the head to the stomach for subsequent PAS staining. The findings in both groups were compared at the three endpoints. Control embryos had neither tracheoesophageal nor notochord malformations. On day 12, only 11/36 adriamycin embryos were normal; 7/36 had abnormal notochords, 11/36 had EA, and 7/36 had both. The corresponding figures for 12.5 days were 12/27, 0/27, 7/27, and 8/27 and those for the day 13 7/23, 5/23, 3/23, and 8/23. The malformed notochords were thickened, bifurcated, or trifurcated in the sagittal plane. The simultaneous presence of notochord and esophageal malformations suggests a direct link between both defects, but our observation of isolated occurrence of both shows that they reflect two expressions of the profound disturbance of embryonic para-axial organization responsible for the cluster of malformations rather than a cause-effect association.
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Pediatric surgery international 15 (1999), S. 457-460 
    ISSN: 1437-9813
    Schlagwort(e): Key words Blunt testicular injury ; Rat ; DNA flowcytometry ; Antisperm antibodies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Injury to the testis breaching the tunica albuginea is known to affect fertility. Blunt testicular trauma with an intact tunica albuginea has been reported to have no effect on contralateral testicular histology and Johnsen testicular maturation score. However, sensitive techniques like DNA flowcytometry have not been utilized so far to evaluate contralateral testicular germ-cell changes. Sixty-four male Wistar rats aged 20 days were randomized into groups I (control), II (unilateral blunt testicular trauma, UBTT), III (UBTT and excision of ipsilateral testis at 6 h), and IV (UBTT and cyclosporine for 30 days). Fertility, DNA flowcytometry of contralateral testicular tissue, and anti-sperm antibodies (ASA) were evaluated. Fertility and haploid-cell percentage of the contralateral testis were significantly decreased compared to controls in early adulthood (100 days). Around 150 days of age, as ASA decreased significantly, fertility and contralateral testicular haploid-cell population recovered and were comparable to the controls. Excision of the traumatized testicle around 6 h after injury or administration of cyclosporine for 30 days protected fertility and the contralateral testis. In contrast to group II rats, ELISA for ASA was negative in group III and IV rats. UBTT affects the contralateral testis and fertility. ASA mediate this damage. Orchidectomy performed around 6 h after trauma or short-term cyclosporine therapy prevents the damage.
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Pediatric surgery international 15 (1999), S. 287-289 
    ISSN: 1437-9813
    Schlagwort(e): Key words Soft-tissue tumor ; Myositis ossificans ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Two cases on myositis ossificans circumscripta (MOC) in the arm are reported. Plain X-ray films and magnetic resonance imaging (MRI) were performed in both cases. In the first, an intramuscular tumor-like mass without calcifications was found on MRI with soft-tissue edema extension. In the second, MRI disclosed additional bone-marrow edema. The diagnosis of MOC was confirmed by biopsy in one case and by follow-up in the other. MOC is a benign soft-tissue lesion that is rare in children, with an acute course and usually spontaneously favorable evolution. The differential diagnosis from an infection or a malignant tumor remains difficult. The best imaging modalities are conventional radiography and MRI. The MRI patterns of MOC are typical but not pathognomonic; typical MRI findings in conjunction with clinical symptoms during the early phase of MOC permit the postponement of a biopsy or aggressive surgical procedures. Surgery is indicated for cases not showing typical MOC calcifications at a later stage.
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  • 55
    ISSN: 1437-9813
    Schlagwort(e): Key words Unilateral undescended testis ; Rat ; Testicular injury ; DNA flowcytometry ; Anti-sperm antibody
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This study was designed to evaluate whether creation of a unilateral undescended testis (U/L UDT) in rats by direct fixation of the testis can lead to changes in the contralateral (C/L) descended testis, and if so, whether this inherent problem of the model could be eliminated by anchoring the divided gubernaculum to indirectly fix the testis. Thirty male newborn rats were divided into three groups of 10 each and the procedure done on the 2nd day of life to create U/L UDT according to the group allocated: group I: sham-operated; group II: anchoring the gubernaculum after gubernaculectomy; group III: Direct suture fixation of the testis. Fertility, C/L testicular weight (TW), Johnsen score, seminiferous tubular diameter (STD), DNA flowcytometry, and serum anti-sperm antibodies (ASA) were studied. Fertility, C/L TW, Johnsen score, STD, and haploid cell population were significantly reduced in group III compared to group II, while significantly higher titers of ASA were found in group III. Gubernaculectomy and anchoring the gubernaculum to the anterior abdominal wall is a better technique of creation of experimental UDT, as direct fixation of the testis is potentially detrimental to the C/L normal, descended testis.
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  • 56
    ISSN: 1432-2161
    Schlagwort(e): Key words Hip joint ; Osteonecrosis ; MRI ; Bone scintigraphy ; Femoral head ; Transtrochanteric rotational osteotomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Objective. To assess the ability of bone scintigraphy and magnetic resonance imaging (MRI) to predict the outcome of transtrochanteric rotational osteotomy (TRO) for osteonecrosis of the femoral head (ONFH). Design. This study was a prospective evaluation of imaging techniques. Patients and methods. MRI and bone scintigraphy were performed on 20 hips in 18 patients at 3 months after TRO. The radiographic findings at 3 months after TRO, and the MRI and bone scintigraphic findings, were compared with the radiographic findings at final follow-up (mean 39 months). Results and conclusions. On MRI a low-intensity area or a low-intensity band in the new weight-bearing area extending over the acetabular edge on T1-weighted images was related to the presence of collapse on the radiographs at final follow-up. In hips with an area of absent activity in the new weight-bearing surface on bone scintigraphy, collapse was seen more frequently on radiographs at final follow-up than in hips without this feature. Bone scintigraphy was no more specific than radiography in predicting the outcome after TRO. We consider MRI to be superior to bone scintigraphy in predicting the occurrence of collapse, which is one of the major short-term problems after TRO.
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  • 57
    ISSN: 1432-2161
    Schlagwort(e): Key words Lipoma arborescens ; Synovial membrane ; MRI ; Shoulder ; Bursitis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  A 44-year-old man presented with lipoma arborescens of the right shoulder, associated with a rotator cuff tear. MRI revealed villous proliferations with signal intensity of fat on all pulse sequences. At surgery, this bursa was found to contain moderately yellow cloudy fluid without fat globules. Histological examination of the lesion showed subsynovial accumulation of mature fat cells.
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 298-304 
    ISSN: 1432-2161
    Schlagwort(e): Key words Osteosarcoma ; MRI ; Metastases ; skeletal muscle ; Soft tissue neoplasm
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Two cases of osteogenic sarcoma with skeletal muscle metastases are described. A 40-year-old woman presented with progressive swelling of both calves and a soft tissue back lump. She had been diagnosed with mandibular chondroblastic osteogenic sarcoma 6 years earlier. Radiographs showed calcified masses. MRI scans and bone scintigraphy revealed multiple soft tissue masses in both calves. Bone scintigraphy also showed uptake in the back lump, right thigh and left lung base. Biopsy confirmed metastatic chondroblastic osteogenic sarcoma, which initially responded well to chemotherapy. However, the metastatic disease subsequently progressed rapidly and she died 21 months after presentation. The second case concerns a 20-year-old man who presented with a pathologic fracture of the humerus, which was found to be due to osteoblastic osteogenic sarcoma. He developed cerebral metastases 17 months later, followed by metastases at other sites. Calcified masses were subsequently seen on radiographs of the abdomen and chest. CT scans confirmed the presence of densely calcified muscle metastases in the abdominal wall, erector spinae and gluteal muscles. The patient’s disease progressed rapidly and he died 30 months after presentation.
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 342-346 
    ISSN: 1432-2161
    Schlagwort(e): Key words Chordoma ; Notochordal rest ; MRI ; Vertebra
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Chordomas of the lumbar vertebral bodies are rare. We report an unusual case of an entirely intra-osseous chordoma of the fifth lumbar vertebra treated by vertebrectomy. Conventional radiographs and scintigraphy were normal. The lesion was well visualised by MR imaging, but showed only slight sclerosis on CT. We give our reasons for making a diagnosis of chordoma rather than giant notochordal rest and discuss the problems of management resulting from this diagnostic dilemma.
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 347-349 
    ISSN: 1432-2161
    Schlagwort(e): Key words Plasmacytoma ; Plasmacytoma ; amyloid ; Plasmacytoma ; calcified ; Plasmacytoma ; extraosseous ; Plasmacytoma ; thorax ; Plasmacytoma ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  We report on a rare, calcified, plasma cell tumor of the spine causing progressive myelopathy. Other unusual features were the lack of an osseous lesion at the site of the mass, considerable calcified amyloid within the mass but no identifiable amyloid elsewhere, and normal serum immunoelectrophoresis.
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 33-40 
    ISSN: 1432-2161
    Schlagwort(e): Key words Osteoblastoma ; Spine ; Radiography ; CT ; MRI ; Pathology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Objectives. To illustrate the CT and MRI features of spinal osteoblastomas and correlate the imaging with histological findings. Design. In a retrospective review the CT and MRI features of spinal osteoblastomas with respect to mineralisation, signal intensity (SI), adjacent reactive changes, enhancement following gadolinium-DTPA (5 cases) and adjacent soft tissue masses were compared and correlated with the histological findings including the degree of osteoid formation and matrix mineralisation, vascularity and surrounding reactive changes in bone and soft tissue. Patients. Eleven patients (7 males and 4 females; age range 8–43 years, mean age 19.5 years) with 12 osteoblastomas (1 patient suffered a recurrence) were studied. Results. All lesions showed classical features on CT with varying degrees of matrix mineralisation, whereas MRI identified mineralisation in only eight of 12 cases. MRI showed low signal intensity of the lesion on both T1- and T2-weighted sequences in several cases in the absence of heavy mineralisation. In these cases, histological examination revealed diffuse osteoid production by the tumour. All patients given gadolinium showed enhancement within the tumour on MRI. Reactive bone marrow changes were identified on MRI in 10 cases, and in five of these the changes were at multiple levels. An adjacent soft tissue mass was demonstrated in five cases, but extraosseous tumour was present histologically in only two of these. Conclusions. The MRI appearances of spinal osteoblastomas are varied and show no characteristic features. MRI may also overestimate the extent of the lesion due to extensive reactive changes and adjacent soft tissue masses. CT should continue to be the investigation of choice for the characterisation and local staging of suspected spinal osteoblastomas.
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  • 62
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 49-51 
    ISSN: 1432-2161
    Schlagwort(e): Key words Cryptococcoma ; sacrum ; Cryptococcoma ; immunocompromised ; MRI ; sacrum ; CT ; sacrum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Cryptococcoma of the sacrum was the initial presentation of systemic cryptococcosis in a patient on chronic steroid therapy for autoimmune hepatitis. The bone lesion was the only overt manifestation of systemic cryptococcal disease, which preceded other clinical manifestations and led to the subsequent diagnosis of systemic infection.
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  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 545-560 
    ISSN: 1432-2161
    Schlagwort(e): Key words Trauma ; Joints ; injuries ; Joints ; radiography ; Joints ; MRI ; Cartilage ; Bones ; fractures
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Fractures involving the articulating surfaces of bone are a common cause of chronic disability after joint injury. Acute fractures of the articular surface typically run parallel to the surface and are confined to the cartilage and/or the immediate subchondral cancellous bone. They should be distinguished from vertical or oblique bone fractures with intra-articular extension. This article reviews the mechanism of acute articular surface injuries, as well as their incidence, clinical presentation, radiologic appearance and treatment. A classification is presented based on direct inspection (arthroscopy) and imaging (especially MRI), emphasizing the distinction between lesions with intact (subchondral impaction and subchondral bone bruises) and disrupted (chondral, osteochondral lesions) cartilage. Hyaline cartilage, subchondral bone plate and subchondral cancellous bone are to be considered an anatomic unit. Subchondral articular surface lesions, osteochondral fractures and solely chondral fractures are different manifestations of impaction injuries that affect the articulating surface. Of the noninvasive imaging modalities, conventional radiography and MRI provide the most relevant information. The appropriate use of short tau inversion recovery, T1-weighted and T2-weighted (turbo) spin-echo as well as gradient-echo sequences, enables MRI to classify the various acute articular surface lesions with great accuracy and provides therapeutic guidance.
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 658-660 
    ISSN: 1432-2161
    Schlagwort(e): Key words Medial collateral ligament ; tear ; interposition ; Knee ; MRI ; Posterolateral dislocation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Displacement of the medial collateral ligament (MCL) into the medial knee joint is an extremely rare finding associated with MCL tears, and is easily diagnosed on magnetic resonance imaging. A case of intra-articular interposition of the MCL during a severe knee injury is presented. A radiolucent ”fat stripe” sign and adjacent skin dimpling on radiographs may be relatively specific indicators of this injury.
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  • 65
    ISSN: 1432-2161
    Schlagwort(e): Key words Shoulder ; arthrography ; Shoulder ; comparative studies ; Shoulder ; injury ; Shoulder ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Purpose. In a patient with internal derangement of the shoulder, the diagnostic method of choice is controversial. Conventional arthrography can diagnose most rotator cuff tears accurately; however, in many institutions MR arthrography is usually necessary to diagnose labral tears. We utilized decision tree methodology to compare the cost- effectiveness of conventional arthrography and conventional MRI with a hypothetical algorithm in which a patient underwent arthrography, performed with admixed gadolinium, which if negative, was followed by MRI. Design. The use of double-contrast arthrography alone, conventional MRI alone, and gadolinium-enhanced MRI used as an adjunct to conventional arthrography were modeled for the diagnosis of full-thickness rotator cuff tears (RCT), partial RCTs, labral tears, and the absence of cuff/labral tears using decision analysis methodology. English language medical publications were searched to determine the base probabilities for the accuracy of the diagnostic tests. The outcome utilities ranged from –1 to +1 to reflect the value of correct diagnostic evaluation. Charges for diagnostic tests and appropriate surgical treatments were based on 1997 Medicare reimbursement rates for professional fees and hospital charges in an outpatient setting. Sensitivity analyses were performed to evaluate the effects of uncertainty regarding the prevalence of each disease state and the accuracy of several diagnostic tests. Results. In the base-case analysis, the average effectiveness of double-contrast arthrography alone, MRI alone and arthrography selectively followed by MRI were 0.6610, 0.6715, and 0.7204, respectively. The average costs for each of these strategies were $1090, $2033, and $2339, respectively. Conclusion. Arthrography performed with admixed diluted gadolinium, which if negative is immediately followed by MRI, was somewhat more expensive than conventional MRI. However, because of much greater effectiveness, cost-effectiveness was significantly higher for our proposed algorithm. Conventional arthrography without gadolinium, although less expensive, had severely limited effectiveness.
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 61-74 
    ISSN: 1432-2161
    Schlagwort(e): Key words Ligament ; Ligament injury ; MRI ; Soft tissue injury ; Soft tissue trauma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Magnetic resonance imaging has had a dramatic effect on the means by which we diagnose ligament injuries. Tears resulting from either acute trauma or overuse can be detected noninvasively, directing appropriate therapy be it conservative or surgical. For the elite athlete, earlier diagnosis leads to earlier intervention, or alternatively, a normal MRI examination can result in an earlier return to play. While MRI is accepted for the diagnosis of certain injuries such as complete tears of the cruciate ligaments of the knee, other injuries, such as partial cruciate ligament tears or tears of the intercarpal ligaments of the wrist, remain controversial.
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  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 717-722 
    ISSN: 1432-2161
    Schlagwort(e): Key words Sarcoid ; vertebrae ; Sarcoid ; rib ; Sarcoid ; calvarium ; Osteolytic ; CT ; MRI ; Surgical fusion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Skeletal sarcoidosis is rare. This report describes a 31-year-old African American man who presented with a destructive osteolytic lesion of C2 and another lesion in a rib. The lesion at C2 was treated with corpectomy and bone graft. Four months later the lesion recurred and a new lesion was discovered in the cervical vertebral column. The patient declined surgery for instability for another 3 months, choosing to remain in a halo. Seven months following the initial operation, a technetium bone scan showed spread of the disease to the calvarium and thoracic and lumbar vertebrae. The patient had no symptoms referable to these sites. The patient agreed to have his neck fused at this point. For the next 10 months, the patient was on steroids and a further new lesion appeared at L5 without localizing signs or symptoms. The patient declined further evaluation over the next 12 months and is now considered lost to follow-up.
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  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 52-56 
    ISSN: 1432-2161
    Schlagwort(e): Key words Intraneural ganglion ; Peroneal nerve palsy ; Drop foot ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  A case of peroneal nerve palsy caused by an intraneural ganglion is presented. The cystic mass was located posterolateral to the lateral femoral condyle and extended along the common peroneal nerve distal to the origin of the peroneus longus muscle. The nerve was compressed in the narrow fibro-osseous tunnel against the fibula neck and the tight origin of the peroneus longus muscle. The nerve was decompressed by complete tumor excision and transection of the origin of the peroneus longus muscle. Full recovery of nerve function was obtained in 6 months.
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  • 69
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 594-598 
    ISSN: 1432-2161
    Schlagwort(e): Key words Osteochondroma ; Chondroma ; Extraskeletal tumor ; Soft tissue tumor ; Foot ; CT ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  A case of pathologically proven extraskeletal osteochondroma is presented with magnetic resonance imaging (MRI), computed tomography (CT), bone scan and radiographic findings. The diagnosis of extraskeletal osteochondroma should be considered when a discrete, ossified mass is localized in the soft tissues of the distal extremities. Nomenclature surrounding this entity is controversial and is discussed.
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  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 616-620 
    ISSN: 1432-2161
    Schlagwort(e): Key words Joint ; MRI ; Infectious arthritis ; Septic joint ; Inflammation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Objective. To differentiate the MR features of septic versus nonseptic inflamed joints. Design and patients. Thirty patients were referred for MRI with inflamed joints (19 were subsequently found to be septic and 11 nonseptic). At 1.5 T enhanced MRI five groups of signs related to joint space, synovium, cartilage, bone and peri-articular soft tissue respectively were assessed and compared between the septic and nonseptic groups. Results. The prevalence of MRI findings in septic versus nonseptic joints (respectively) was as follows: effusion (79% vs 82%), fluid outpouching (79% vs 73%), fluid heterogeneity (21% vs 27%), synovial thickening (68% vs 55%), synovial periedema (63% vs 55%), synovial enhancement (94% vs 88%), cartilage loss (53% vs 30%), bone erosions (79% vs 38%), bone erosions enhancement (77% vs 43%), bone marrow edema (74% vs 38%), bone marrow enhancement (67% vs 50%), soft tissue edema (63% vs 78%), soft tissue enhancement (67% vs 71%), periosteal edema (11% vs. 10%). The presence of bone erosions appeared to be an indicator for an infected joint (P=0.072); coexistence of bone marrow edema slightly improves the significance (0.068). A similar trend was obtained when combining bone erosions with either synovial thickening, synovial periedema, bone marrow enhancement or soft tissue edema (P=0.075). Conclusions. The combination of bone erosions with marrow edema is highly suggestive for a septic articulation; the additional coexistence of synovial thickening, synovial edema, soft tissue edema or bone marrow enhancement increases the above level of confidence. Similar to conventional radiography, the single sign that appeared to show a significant trend was the presence of bone erosions. However, no single sign or combination could either be considered pathognomonic or exclude the presence of a joint infection.
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 655-657 
    ISSN: 1432-2161
    Schlagwort(e): Key words Acromegaly ; Locking ; Metacarpophalangeal joint ; Osteophyte ; Volar plate hypertrophy ; Radiography ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  A 39-year-old man with acromegaly exhibited locking of metacarpophalangeal (MCP) joints of both index fingers. Large osteophytes were found at the metacarpal heads by radiography and computerized tomography (CT). Magnetic resonance (MR) images revealed hypertrophy of volar plates. We suggest that these characteristic acromegalic features caused locking of MCP joints. Surgery was required on one of the joints to release the locking.
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 703-709 
    ISSN: 1432-2161
    Schlagwort(e): Key words Proliferative myositis ; Childhood ; Lumbar muscles ; Ossification ; X-ray ; CT ; MRI ; PET
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  A case of proliferative myositis in the lumbar paraspinal muscles in a 14-year-old boy is presented. Imaging investigations including plain radiograph, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), bone scan and positron emission tomography (PET) were suggestive of an inflammatory process such as myositis ossificans. The diagnosis was made by incisional biopsy. More pronounced edema, more muscle fiber necrosis and a higher cellularity were found compared to adult cases. The karyotype of the lesion was normal. Clinically, the mass disappeared spontaneously. After 24 months, asymptomatic bridging ossification between the third and fourth lumbar vertebrae was noted.
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  • 73
    ISSN: 1432-2161
    Schlagwort(e): Key words Shoulder ; Biceps tendon ; Anomaly ; Arthroscopy ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  A developmental anomaly of the long head of the biceps tendon was found in a cadaveric shoulder. Findings on arthroscopy, routine MR imaging, and MR arthrography were compared and correlated with results of anatomic dissection. MR arthrography appears to be a very good diagnostic imaging method for depicting this anomaly prior to arthroscopy.
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  • 74
    ISSN: 1432-2307
    Schlagwort(e): Key words Pyruvate kinase isoenzymes ; N-Nitrosomorpholine ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The expression of the pyruvate kinase (PK) isoenzymes L and M2 was analysed in the livers of rats treated with the hepatocarcinogenic agent N-nitrosomorpholine (NNM) in the drinking water. In control animals L-PK expression was restricted to liver parenchymal cells, whereas M2-PK was detected in bile duct epithelial, blood vessel wall, endothelial and Kupffer cells. In rats treated with NNM proliferating oval cells were consistently L-PK negative and M2-PK positive, while the ductal cells of cholangiofibroses were clearly L-PK positive and coexpressed M2-PK. However, no morphological differentiation of ductal cells into hepatocyte-like cells was observed. In the clear and acidophilic cell foci storing glycogen in excess strong staining for L-PK was observed. In glycogen-poor foci induced by NNM a shift from L-PK to M2-PK expression takes place.
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  • 75
    ISSN: 1432-2307
    Schlagwort(e): Key words Medullary thyroid carcinoma ; Basement membrane ; Laminin ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Medullary thyroid carcinoma (MTC) originates from C cells, which secrete calcitonin (CT), their specific marker. C cells are located in contact with the basement membrane (BM) of the thyroid follicles, which is partly made up of the laminin-2 isoform synthesized by thyrocytes. During oncogenesis, proliferation of the C cells, invading the centre of the follicles, leads to a break in their normal contact with the BM. As specific interactions of cells with BM components, especially laminins, are important for proliferation and differentiation, we investigated the relationships of normal and neoplastic C cells with laminin in the Wag/Rij rat model of human MTC. Immunocytochemical studies showed a progressive loss of the laminin layer underlying the hyperplastic C cell nodules around the large dedifferentiated tumours. The α2, β1 and γ1 chains of the laminin-2 isoform were synthesized and secreted by rat MTC 6–23 cell cultures and the tumours induced by subcutaneous injection of these cells. In situ hybridization combined with anti-CT immunocytochemistry showed a low expression of α2 mRNA on differentiated C cells and thyrocytes, but an overexpression on immunonegative spontaneous MTC and induced intrathyroid tumours. The high level of α2 gene expression, together with tumour dedifferentiation, suggests a relationship with malignancy.
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  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Urological research 27 (1999), S. 41-47 
    ISSN: 1434-0879
    Schlagwort(e): Key words Ureter ; Histology ; Polyuria ; Diabetes mellitus ; Nephrectomy ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The influence of increased functional load on the macroscopical and histological appearance of the ureter was investigated. Sixty rats were divided into five groups: (1) sucrose-fed rats with non-osmotic polyuria; (2) diabetic rats with osmotic polyuria; (3) uninephrectomized rats; (4) sham-operated control rats; and (5) control rats. The 24-hour urinary volume was measured on days 7, 14 and 21. Growth of the kidney, ureter and bladder was investigated and the histological appearance of the ureter was further evaluated. Diabetic and sucrose-fed rats had comparable polyuria with a seven-fold increase in urinary output. The urinary volume for the remaining kidney was doubled in uninephrectomized rats. After 3 weeks, diabetic rats had increased weight of the kidney, ureter and bladder, sucrose-fed rats had increased weight of the bladder, whereas uninephrectomized rats had increased weight of the kidney and ureter. The cross-sectional area (CSA) of the ureter wall from control rats increased from the proximal to the distal portion. The size of the whole ureter from diabetic rats was dramatically increased, the CSA of the wall of the distal ureter portion being four times that of the controls. The CSA of the ureter wall from sucrose-fed rats was increased only in the distal portion, whereas the ureter from uninephrectomized rats was increased only in the proximal portion. The results demonstrate the importance of differentiating between different portions of the rat ureter when examining histological sections of this organ. Moreover, polyuria per se is shown to induce growth of the bladder and of the adjacent distal part of the ureter, whereas uninephrectomy and diabetes caused growth of the kidney and the upper parts of the ureter, in addition to the growth induced by polyuria.
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  • 77
    ISSN: 1434-0879
    Schlagwort(e): Key words Nonbacterial prostatitis ; Animal model ; Partial urethral obstruction ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The pathogenesis of nonbacterial prostatitis (NBP) is not understood mainly due to the lack of appropriate experimental models. We developed a new experimental model of NBP by inducing a partial obstruction of the urethra (PUO) in the rat. Male Wistar rats aged 12 weeks were used. PUO was produced by a nylon ligature on the urethra over a rubber tube. The tube was slipped out after the ligature had been tied. Two rats were examined histologically 6 h, 1 day, 3 days and 7 days after PUO. In another group, two rats were killed at 1, 3 and 7 days after the release of the PUO that had been left in place for 3 days. On day 3, another eight rats with PUO and eight control rats had 2 ml of urine in the bladder replaced by the same volume of lucifer yellow (LY; 10 μg/ml, MW 500), microperoxidase (MP; 20 μg/ml, MW 1900), horseradish peroxidase (HRP; 10 μg/ml, MW 40 000), or saline as control, respectively. Lymphocytic infiltration and interstitial edema were noted in the prostate following PUO, being most prominent on day 3. After the release of the PUO, these inflammatory changes gradually disappeared. Only LY was noted within the prostatic stroma of the rats 2 h after bladder instillation. Intraprostatic urinary reflux may be an etiologic factor in NBP. The present study showed that lower urinary tract obstruction caused NBP in the rat. Penetration of prostatic tissue by low-molecular-weight substances in the urine may trigger NBP.
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Urological research 27 (1999), S. 476-482 
    ISSN: 1434-0879
    Schlagwort(e): Key words Urinary bladder ; Enterocystoplasty ; Cecocystoplasty ; Innervation ; Nerve growth ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Incorporation of bowel into the bladder (enterocystoplasty) has been widely used to increase bladder capacity. It has been reported by others that the response of smooth muscle from the cystoplastic segment of the intestine shifts from that of the intestine (relaxation to α-agonists and ATP) to that of the bladder (contraction to α-agonists and ATP). This suggests a functional integration of the intestinal muscle into the bladder; the mechanisms are unknown. The aims of the present study were (1) to elucidate if there are signs of bladder nerves sprouting across the anastomosis into the intestinal segment, and (2) to study what happens with the intrinsic innervation of the intestinal segment. As a model, we used cecocystoplasty in rats. The bladder was opened and a patch of cecum with intact vascular supply was anastomosed to the bladder. After two to 11 months the rats were sacrificed and the bladders mounted as wholemounts and stained for acetylcholinesterase-containing nerves, or embedded in paraffin for histology. A pronounced degeneration of the myenteric plexus was found in the cecal segments. In some areas, this had proceeded to the extent that the ganglia were isolated ovoid lumps of cells with no apparent connection to other ganglia. Areas lacking ganglia and nerve trunks but still with muscle could be found in all specimens. Abundant axon bundles were demonstrated sprouting from the cut bladder nerves close to the anastomosis. The bundles spread out in a fan-like pattern or were organized as fewer thicker nerves. There were many nerve bundles entering the cecal segment where they branched and the diameter decreased till they no longer became visible. Some nerves reached surviving lumps of myenteric ganglion cells. The results show that the bladder nerves sprout into the anastomosed cecal segment. It is reasonable to assume that these nerves are responsible for the changes in receptor pharmacological properties of the cecal smooth muscle towards that of bladder muscle.
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Urological research 27 (1999), S. 174-179 
    ISSN: 1434-0879
    Schlagwort(e): Key words Apoptosis ; Ischemia-reperfusion ; Blood flow ; Ischemia ; Prostate ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The mechanisms involved in the castration-induced involution of the ventral prostate (VP) are not fully understood. It was recently reported that castration decreases blood flow in the VP in rats and that this occurs before the apoptotic involution of the organ. However, it is unknown whether a decrease in blood flow may trigger apoptosis in the VP, and this was therefore examined in this study. The right iliac artery was clamped for 1 h in adult male rats. After 24 h of reperfusion, the VPs were frozen or fixed. In situ end-labeling (ISEL) was used to identify apoptotic cells, and testosterone repressed prostatic message-2 (TRPM-2) was measured. Proliferating cell nuclear antigen (PCNA) immunohistochemistry was used to identify proliferating cells. Clamping the right iliac artery reduced blood flow in the right VP to 0.17 of that in the contralateral lobe. This relative ischemia resulted in a threefold increase in the volume density of apoptotic epithelial cells on the treated side, but left cell proliferation unaffected. Testosterone substitution did not change this pattern. This study suggests that a transient period of relative ischemia may induce apoptosis in the rat ventral prostate. This may be of importance for the understanding of castration-induced prostatic involution.
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  • 80
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 199 (1999), S. 265-280 
    ISSN: 1432-0568
    Schlagwort(e): Key words Cat ; Rat ; Immunocytochemistry ; NADPH-diaphorase ; Thalamus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  To gain insight into the cellular organisation of the zona incerta, we have examined the chemoarchitectonic properties of this ”uncertain zone”. The brains of Sprague-Dawley rats and common cats were processed for immunocytochemistry or NADPH-diaphorase histochemistry using standard methods. For the immunocytochemistry, antibodies to γ-aminobutyric acid (GABA), glutamic acid decarboxylase (GAD), parvalbumin, calbindin, tyrosine hydroxylase, somatostatin, serotonin and glutamate were used. Two general patterns of distribution in the zona incerta were seen. First, labelled cells were restricted largely to one of the cytoarchitectonically defined sectors of the zona incerta. For instance, GABA, GAD and parvalbumin-immunoreactive cells were found principally within the ventral sector, NADPH-diaphorase and glutamate-immunoreactive cells within the dorsal sector and tyrosine hydroxylase- and somatostatin-immunoreactive cells within the rostral sector. Second, labelled cells were scattered somewhat across all incertal sectors, with no clear region of concentration. This pattern included the calbindin- and serotonin-immunoreactive cell groups. These results indicate that the zona incerta is made up of many neurochemically distinct cell groups, some of which respect the well-defined cytoarchitectonic boundaries of the nucleus, whilst others do not. This rich neurochemical diversity in the zona incerta suggests that this nucleus may have differential effects on the different structures that it projects to.
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  • 81
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 200 (1999), S. 521-531 
    ISSN: 1432-0568
    Schlagwort(e): Key words Development ; Internal capsule ; Nucleus basalis ; Rat ; Thalamus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  This study defines several features of the early connections of the developmentally transient perireticular thalamic nucleus of rats. The neocortex of developing rats was injected with either DiI, biotinylated dextran, WGA-HRP (wheatgerm agglutinin conjugated-horseradish peroxidase), fluorescent latex beads or cholera toxin subunit B (CTB) and their brains were processed for tracer detection with standard methods. In general, tracer injections into various regions of the developing neocortex revealed no labelled neurones within the perireticular nucleus, although some of these tracers (WGA-HRP, dextran) labelled many of the amoeboid microglial cells that are found within this nucleus. There were, however, many retrogradely labelled neurones in a region adjacent to the perireticular nucleus, within the nucleus basalis of the basal forebrain (medial edge of globus pallidus). Their identity was confirmed as neurones of the nucleus basalis since they were all were similar in morphology and somal size to neurones that were immunoreactive to NGFr (nerve growth factor receptor), an antigen found only among neurones of the nucleus basalis and basal forebrain. Moreover, double labelling experiments revealed that most, if not all, of the cortically labelled neurones were NGFr-immunoreactive also. Thus, in conclusion, our results suggest that the perireticular nucleus does not project to the neocortex; the only neurones in the general vicinity of the perireticular nucleus that have a cortical projection form part of the nucleus basalis.
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 200 (1999), S. 533-540 
    ISSN: 1432-0568
    Schlagwort(e): Key words Coronary vasculogenesis ; Angiogenesis ; Coronary artery ; Development ; Rat ; Embryonic heart
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The aim of this work was to address spatiotemporal and morphologic patterns of coronary artery development in rats, based on immunohistochemical and ultrastructural studies of hearts at different stages of prenatal development. Griffonia simplicifolia I lectin and α-smooth muscle antibody were used to demonstrate endothelial cells and/or their precursors and smooth muscle cells, respectively. Ultrastructural examination was performed on ED14–16 hearts to study the morphology of the developing coronary arteries in different regions of the truncus arteriosus and adjacent myocardium. On ED14 endothelial-like cells present within the mesenchyme surrounding the outflow tract penetrated the aortic wall and the truncoconal proximal myocardium. On ED15 these penetrating cells formed vascular clusters, which were the first signs of presumptive vascular channels. Development of the coronary artery proceeded by coalescence of discontinous vascular clusters, formation of the lumen (vascular channels) and establishing a connection of the proximal part with the aorta. The second layer of cells around vascular channels (embryonic media) consisted of mesenchymal cells that were attracted to the immature vessel and were first seen on ED15. At this time no lumenized connection of the coronary artery with the aorta has been seen. After the lumenized connection of the coronary artery with the aorta had been established perivascular cells of the media started to differentiate into vascular smooth muscle, as was shown by α-smooth muscle actin-staining. Further development and differentiation of the media and adventitia proceeded distally (towards the apex).
    Materialart: Digitale Medien
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  • 83
    ISSN: 1432-0568
    Schlagwort(e): Key words Morphogenesis ; Histochemistry ; Lectins ; Carbohydrates ; Salivary glands ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The developmental expression of salivary glycoconjugates was investigated in the rat submandibular and sublingual glands by conventional and lectin histochemistry. By the time of the first differentiation of secretory structures, in spite of similar morphological features, a different histochemical reactivity was detected, accounting for a relevant content of neutral glycoconjugates in the submandibular gland and the occurrence of both neutral and acidic glycoconjugates in the sublingual one. The use of lectins allowed the main changes of secretory components to be noted around gestational day 18. DBA and WGA lectins seemed to act as pre- and post-natal development markers while Con A lectin was indicative of post-natal differentiation. Taken together, data from lectin histochemistry indicated the transitional occurrence of glycoconjugates, probably involved in temporally restricted functions, as well as the co-existence of different secretory components that might also reflect maturational changes of single products.
    Materialart: Digitale Medien
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  • 84
    ISSN: 1432-0533
    Schlagwort(e): Key words Clomethiazole ; Rat ; Spinal cord-injury ; Neuroprotection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Clomethiazole (CMZ) has a neuroprotective effect in experimental focal and global forebrain ischemia. This neuroprotective effect may depend on its ability to enhance GABA receptor activity. We have studied the effect of pretreatment with CMZ on motor function recovery and nerve cell damage after spinal cord injury (SCI). Rats were randomized and 30 min before SCI they received a single intraperitoneal dose of CMZ (150 mg/kg) or saline. The spinal cord was injured with a 50 g (4.5 g/mm2) load, applied over the exposed dura, through a curved rectangular plate (2.2 × 5.0 mm) for 5 min at T8–9. The animals became paraplegic 1 day after injury. The rats were evaluated for recovery of hind limb motor function. All animals recovered to some extent over the observation period of 12 weeks. However, hind limb motor function was significantly better in the animals pretreated with CMZ. At 12 weeks the rats were killed and perfused/fixed for morphological investigations. Microtubule-associated protein 2 (MAP2) immunostaining was used to stain neurons and dendrites and Luxol-fast blue to stain myelinated tracts of the white matter. The injured segment of the spinal cord showed severe atrophy, distortion, cavitation and necrosis of grey and white matter. Compared to uninjured controls the transverse sectional area was reduced to 32.7 ± 4% in untreated animals but only to 38.5% ± 4.1 in CMZ-treated animals. MAP2 staining showed that, compared to uninjured controls, grey matter was reduced to 7.4 ± 2.7% in saline-treated injured animals and to 22.7 ± 5.4% in CMZ-treated rats. Our results thus show that in this model CMZ improves hind limb motor function and attenuates the morphological damage to the spinal cord.
    Materialart: Digitale Medien
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 200 (1999), S. 413-417 
    ISSN: 1432-0568
    Schlagwort(e): Key words Receptor cell ; Axon ; Vomeronasal organ ; Regeneration ; Rat ; HRP-WGA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Chemosensory neurons in the vomeronasal epithelium (vomeronasal neurons) regenerate following experimentally induced degeneration. Transection of the vomeronasal nerves leads to retrograde degeneration of vomeronasal neurons followed by replacement of the cell population. The projection of the axons of regenerated vomeronasal neurons was examined by horseradish peroxidase(HRP) histochemistry and electron microscopy. HRP-wheat germ agglutinin (WGA) was placed on the surface of the vomeronasal organ of the rat. Dense distribution of HRP-labeled fibers was observed in the vomeronasal nerve and glomerular layers in the accessory olfactory bulb (AOB) of the intact rat. At one week after transection, HRP-labeled fibers were not found in the AOB, and no labeled fibers could be observed on the medial surface of the olfactory bulb where the vomeronasal nerve traversed. Three weeks after transection, labeled fiber bundles were observed on the medial surface of the olfactory bulb in all animals. No labeled fibers were detected in the AOB. From 12 to 32 weeks after transection, projection of HRP-labeled fibers was identified in the AOB in 8 out of 26 rats (the incidence of projection was 30%). But the number of projection fibers on the operated side was much smaller than on the control side. Electron microscopy confirmed that the HRP-labeled terminals make synaptic contacts with neurons in the AOB.
    Materialart: Digitale Medien
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  • 86
    Digitale Medien
    Digitale Medien
    Springer
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 208 (1999), S. 50-56 
    ISSN: 1431-4630
    Schlagwort(e): Key words Flavor enhancer ; Savory flavoring ; Taste ; Amino acids ; Partial least squares regression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract  Enzymatically hydrolyzed vegetable protein was produced from soy protein using hydrolysis times of 0–20 h. The development of sensory properties and the pattern of protein degradation was followed. Around two-thirds of the final amount of free amino acids and degree of hydrolysis (DH) were achieved during the first 4 h of hydrolysis. Between 6 h and 10 h of hydrolysis the bouillon-like tastes increased significantly (P〈0.001). In this time interval the amount of free amino acids exceeded 40% of the total amino acids and the DH exceeded 50% of the theoretically possible (100%). Using partial least squares regression with standardisation of free amino acid data according to their taste threshold values showed that free glutamic acid, aspartic acid and lysine correlated with the bouillon-like tastes. By standardisation of free amino acid data with respect to their SD the specificity of the enzymes for amino acid side-chains could be seen.
    Materialart: Digitale Medien
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  • 87
    ISSN: 1279-8517
    Schlagwort(e): Anterior cruciate ligament ; Kinematics ; Knee ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Ce travail a pour but de proposer à l'aide d'un modèle informatique 3D du genou chez un sujet vivant une étude anatomique des modifications de longueur du ligament croisé antérieur (LCA) et de ses faisceaux au cours de la flexion. La méthode d'évaluation proposée est une reconstruction informatique 3D, à partir de coupes IRM, reproduisant le mouvement de flexion du genou de 0 à 75°. Vingt-et-une coupes ont été réalisées pour chacune des 13 positions de flexion. La reconstruction de Delaunay et le recalage de chaque position permettent d'obtenir un modèle 3D. Ce modèle permet le suivi d'un point osseux lors du mouvement. En connaissant le déplacement relatif des insertions ligamentaires, il est possible de préciser la biométrie du ligament en calculant la longueur des faisceaux du LCA à chaque position, de mettre en évidence les variations de longueur au cours du mouvement. La longueur moyenne du ligament était de 34 mm. Le faisceau antéro-médial était plus long de 30 % par rapport aux deux autres faisceaux. Lors de la flexion, le faisceau antéro-médial était peu modifié (cette caractéristique semblait en faire une position de référence pour une ligamentoplastie), le faisceau postéro-latéral se tendait à partir de 30°, le faisceau intermédiaire se détendait dès le début du mouvement. En retrouvant les données de la littérature, cette méthode permet une approche anatomique du LCA faisceau par faisceau lors du mouvement de flexion.
    Notizen: Summary The aim of this study is to suggest an anatomic study of the modifications of the length of the anterior cruciate ligament (ACL) and its bundles during flexion with the aid of a 3D computerized model of the knee in a living subject. The method of evaluation suggested is a 3D computerized reconstruction based on MRI sections, reproducing the movement of flexion of the knee from 0 to 75°. Twenty-one sections were made for each of the 13 positions of flexion. The reconstruction of Delaunay and the realignment of each position provided a 3D model which allowed monitoring of a bony point during the movement. By knowing the relative displacement of the ligamentous attachments it was possible to define the biometry of the ligament by calculating the length of the bundles of the ACL in each position and to demonstrate the variations in length during the movement. The mean length of the ligament was 3.4 mm. The anteromedial bundle was longer by 30% compared with the other two bundles. During flexion the anteromedial bundle was not much modified (this feature seems to provide a reference position for a ligamentoplasty), the posterolateral bundle became taut after 30°, and the intermediate bundle relaxed from the beginning of movement. Based on the data from the literature, this method allows an anatomic approach to the ACL, bundle by bundle, during flexion movement.
    Materialart: Digitale Medien
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  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 208 (1999), S. 355-361 
    ISSN: 1431-4630
    Schlagwort(e): Key words Flavor enhancer ; Taste ; Amino acids ; Carbohydrates ; Maillard reaction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract  Hydrolyzed vegetable protein produced using hydrochloric acid (HVP) or proteolytic enzymes (EVP) was given a maturation period of up to 6 weeks at 30  °C. The maturation resulted in a darker color for both hydrolysates, but the sensory profiles were not altered to any great extent. For both hydrolysates a decrease in the amount of free amino acids or an increase in the amount of bound amino acids was seen, and for EVP, a decrease in the amount of free monosaccharides was likewise observed. In HVP the mono- and polysaccharides were destroyed during hydrolysis. The changes in amino acids could be due to, for example, a reversible binding to either a monosaccharide in EVP or a degradation product of carbohydrates in HVP, leading to the first stage of the Maillard reaction. These early reactions did not proceed to any flavor-giving Maillard reaction compounds. Maturation can therefore not be used to enhance the flavor of protein hydrolysates under the applied production conditions.
    Materialart: Digitale Medien
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  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 208 (1999), S. 183-188 
    ISSN: 1431-4630
    Schlagwort(e): Key words Sulphadimidine ; Fermented sausage ; Carbon-14-labelling ; Rat ; Bound residues
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract  Sulphadimidine (SDM), a drug frequently administered to pigs, is partially converted into other compounds by processing meat to produce raw, fermented sausage. With the aid of 14C-labelled SDM, evidence was obtained that part of the radioactive matter was covalently bound to the matrix. Part of these bound residues could be released in vitro by 4 M HCl at 21  °C or by 0.024 M HCl at 37  °C. Female rats were also able to release bound SDM residues and to excrete these in their urine, in amounts approaching those obtained by treatment with 4 M HCl. Both the parent compound and its main metabolite, N 4-acetyl-SDM, were observed in the urine of rats.
    Materialart: Digitale Medien
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  • 90
    ISSN: 1432-1211
    Schlagwort(e): Key words Class II MHC sequence ; Rat ; Cloning ; RT-PCR ; Polymorphism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
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  • 91
    Digitale Medien
    Digitale Medien
    Springer
    European radiology 9 (1999), S. 336-343 
    ISSN: 1432-1084
    Schlagwort(e): Key words: Cryptorchidism ; Scrotum ; US ; CT ; MRI ; Testis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. Imaging evaluation of the patient with a non-palpable testis has evolved over recent decades. The rational explanation of imaging in these patients requires a clear understanding of the various causes of a non-palpable testis, and an appreciation of the utility and limitations of the available imaging modalities. This review describes the classification of non-palpable testis and discusses the role of modern imaging in evaluation. In particular, the relative accuracies of ultrasound, CT and MRI is reviewed.
    Materialart: Digitale Medien
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  • 92
    ISSN: 1432-1106
    Schlagwort(e): Key words Coherence ; Entorhinal cortex ; Cortex ; Hippocampus ; Amygdala ; 192 IgG-saporin ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Changes in brain electrical activity in response to cholinergic agonists, antagonists, or excitotoxic lesions of the basal forebrain may not be reflective entirely of changes in cholinergic tone, in so far as these interventions also involve noncholinergic neurons. We examined electrocortical activity in rats following bilateral intracerebroventricular administration of 192 IgG-saporin (1.8 µg/ventricle), a selective cholinergic immunotoxin directed to the low-affinity nerve growth factor receptor p75. The immunotoxin resulted in extensive loss of choline acetyl transferase (ChAT) activity in neocortex (80%–84%) and hippocampus (93%), with relative sparing of entorhinal-piriform cortex (42%) and amygdala (28%). Electrocortical activity demonstrated modest increases in 1- to 4-Hz power, decreases in 20- to 44-Hz power, and decreases in 4- to 8-Hz intra- and interhemispheric coherence. Rhythmic slow activity (RSA) occurred robustly in toxin-treated animals during voluntary movement and in response to physostigmine, with no significant differences seen in power and peak frequency in comparison with controls. Physostigmine significantly increased intrahemispheric coherence in lesioned and intact animals, with minor increases seen in interhemispheric coherence. Our study suggests that: (1) electrocortical changes in response to selective cholinergic deafferentation are more modest than those previously reported following excitotoxic lesions; (2) changes in cholinergic tone affect primarily brain electrical transmission within, in contrast to between hemispheres; and (3) a substantial cholinergic reserve remains following administration of 192 IgG-saporin, despite dramatic losses of ChAT in cortex and hippocampus. Persistence of a cholinergically modulated RSA suggests that such activity may be mediated through cholinergic neurons which, because they lack the p75 receptor, remain unaffected by the immunotoxin.
    Materialart: Digitale Medien
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  • 93
    ISSN: 1432-1106
    Schlagwort(e): Key words Spatial function ; Water maze ; Procedural learning ; Cerebellum ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Recently, we demonstrated the prevalent role of cerebellar networks in the acquisition of the procedural components of spatial information by testing hemicerebellectomized (HCbed) rats in a classical spatial task, the Morris water maze (MWM). As procedures used in the water maze are a mixture of different components (that is, general procedures, exploration procedures, direct reaching procedures), for optimally solving a spatial task all procedural components must be opportunely managed. Thus, severely impaired procedural learning of cerebellar origin can be better comprehended by fractionating the procedural facets. To this aim, a two-step water-maze paradigm was employed. Normal rats were first trained to search for a hidden platform moved to a different position in each trial, utilizing a water maze setting in which visual cues were abolished by heavy black curtains surrounding the tank. In this paradigm, normal animals solved the task by using general and exploration procedures, but they could not use direct reaching skills. A subgroup of these pretrained animals was then HCbed and, after recovery from cerebellar lesion, was tested in a water maze with normal environmental cues available, a paradigm in which normal animals develop abilities for reaching the target with very direct trajectories. Pretrained HCbed animals, however, did not display the typical spatial deficits of naive HCbed rats, persisted in exhibiting the scanning strategy learned during pretraining, and never displayed direct reaching skills. In conclusion, cerebellar networks appear to be involved in the acquisition of all procedural facets necessary for shifting behavior within the maze until direct reaching of the platform. The lack of flexibility in changing exploration strategies displayed by pretrained HCbed rats is interpreted by taking into account the well-known cerebellar frontal interplay sculpting a specific cerebellar role in the acquisition of spatial procedural steps.
    Materialart: Digitale Medien
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  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 126 (1999), S. 307-314 
    ISSN: 1432-1106
    Schlagwort(e): Key words Striatal dopamine depletion ; Rat ; Locomotion ; Ground reaction forces ; Gait ; Unilateral ; Kinetic ; Centre of mass
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Hemi-parkinsonian rats have preserved postural reflexes but are impaired in initiation of voluntary movements. Surprisingly, these rats can walk and run, suggesting that they can access some compensatory strategy to overcome the rigidity in their impaired limbs. The purpose of the present experiment was to investigate the locomotor compensations made by hemi-parkinsonian rats by measuring the forces exerted by the limbs on the ground throughout the stride during trotting. Rats with unilateral dopamine depletion produced by injection of 6-hydroxydopamine into the nigrostriatal bundle were trained to run back and forth in an alley for food reinforcement. Ground reaction forces were measured in three orthogonal directions using a force plate embedded in the runway. Rats were also videotaped so that limb movements were synchronized with force recordings. Although locomotion was obviously impaired, the affected limbs could support weight and provide some braking forces. In addition, the impaired hindlimb provided significant propulsive force, and a relatively large laterally directed force. Analysis of vertical movement of the centre of mass suggested that the impaired hindlimb was being used partly as a spring. The most significant abnormalities were seen during the diagonal couplet of the impaired forelimb and the unimpaired hindlimb, partly reflecting the important compensatory role of the unimpaired hindlimb. These results demonstrate that this method is useful in the analysis of hemi-parkinsonian gait and provide insights as to how rats can use an impaired limb to produce weight support and propulsion.
    Materialart: Digitale Medien
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 126 (1999), S. 351-358 
    ISSN: 1432-1106
    Schlagwort(e): Key words Tooth pulp ; Phrenic nerve ; Electrical stimulation ; C1 spinal neuron ; Digastric electromyogram ; Somatic receptive field ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Effects of electrical stimulation of the ipsilateral tooth pulp (TP) on C1 spinal neurons were determined in 33 anesthetized rats. One hundred and seven neurons responded to TP stimulation. In 10 rats, the activity of 18 C1 spinal neurons and the amplitude of a digastric electromyogram (dEMG, n=10) increased proportionally during the TP stimulation at an intensity of 1–3 times the threshold for jaw-opening reflex (JOR). Excitatory receptive somatic fields were examined in 61 neurons. Somatic field locations of many neurons (67.2%) involved the ipsilateral face, neck, and jaw. The activity of 45 neurons was increased by both noxious pinch and brushing hair. Of the 107 C1 spinal neurons responding to TP stimulation, 55 were tested to determine the effects of electrical stimulation of the ipsilateral phrenic nerve (PN) above the heart. Twenty-eight of 55 neurons tested were excited; no change in activity was seen for the remaining 27 neurons. The activity of six neurons increased as the intensity of PN stimulation was increased. Excitatory receptive somatic fields were determined in 28 neurons, and somatic field locations of 17 neurons (60.7%) included the ipsilateral face, neck, and jaw. Both noxious pinch and brushing hair excited all 28 neurons. These results suggest that there may be the convergence of face, neck, jaw, TP, and PN afferents on the same C1 spinal neurons in the rat.
    Materialart: Digitale Medien
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  • 96
    ISSN: 1432-1106
    Schlagwort(e): Key words Acetylcholine ; Brain slices ; Cerebral cortex ; Long-term depression ; Rat ; Synaptic plasticity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The ability of layer I activation to facilitate the induction of long-term potentiation (LTP) in layer II/III horizontal connections of motor cortex (MI) was examined in rat brain slice preparations. Field potentials evoked in layer I and layer II/III horizontal pathways were recorded from radially aligned MI sites. While theta burst stimulation (TBS) of layer II/III pathways alone failed to induce LTP, simultaneous TBS of layer I and layer II/III inputs on alternate sides of the recording electrodes induced LTP in the layer II/III input in 8 out of 13 slices (mean change +20±6%; N=13). In the same cases, the layer I connections showed mixed effects: LTP in three cases, LTD in five cases, and no modification in five slices. Despite the facilitatory effect of layer I activation on layer II/III LTP induction, we found that the critical circuitry for this effect was outside layer I. Cutting the layer I fibers selectively in the slice did not prevent layer II/III LTP induction, while cuts preserving only layer I blocked layer II/III LTP after conjoint I+II/III TBS. Cholinergic fibers were evaluated as candidates for the facilitatory effect because they branch widely in both layers and they are thought to participate in synaptic modification. The cholinergic contribution to layer II/III LTP facilitation was investigated using bath application of muscarinic antagonists. Muscarinic blockade prevented facilitation of layer II/III LTP by layer I coactivation. Instead, conjoint stimulation in 10 µM atropine produced long-term depression (LTD) of layer II/III (–18±9%; N=11) as well as of layer I (–21±6%; N=11) horizontal responses. These results indicate that connections formed within layer I are ineffective in promoting LTP in the deeper-lying horizontal connections; the critical route by which layer I stimulation influenced LTP induction required the circuitry in the deeper layers, particularly the cholinergic system. Thus, it appears that diffuse cholinergic afferents provide an additional route to regulate activity-dependent synaptic modificaton in horizontal cortical connections.
    Materialart: Digitale Medien
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  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 127 (1999), S. 298-306 
    ISSN: 1432-1106
    Schlagwort(e): Key words Motor unit ; Contraction ; Stimulation pattern ; Rat ; Medial gastrocnemius
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The effects of irregularity in the pattern of stimulation on the tension produced by motor units in the rat medial gastrocnemius muscle were investigated. The effects of decreasing as well as increasing the interpulse intervals were observed for each motor unit in tetani fused to different degrees. For each motor-unit type, it was found that the effects of these changes depended on the extent of tetanic fusion. Decreasing the interpulse interval produced an increase in tension during the tetanus: the more fused the profile of tetanus, the smaller the tension increase. Increasing the interpulse interval resulted in a decrease in tetanic tension. This effect was most prominent when the tetanic fusion index was approximately 0.75. This phenomenon resulted from the prolongation in relaxation when tetanic fusion increased, thereby preventing a decrease in tension when the interpulse interval increased. We also investigated the effects of introducing a short interpulse interval (”doublet”) at the beginning of the stimulation. The doublets produced increased tetanic tension with a more fused profile. However, the doublet enhanced the sensitivity of the tetanus to increases in interpulse interval and decreased its sensitivity to decreases in interpulse intervals. Slow-twitch motor units appeared to be significantly less sensitive to both increases and decreases in interpulse interval than fast-twitch units. This suggests that slow-twitch units are better suited for producing long-lasting contractions with a constant tension level. Conversely, the high sensibility of fast-twitch units to changes in stimulation frequency enhances their participation in regulation of tension of the muscular contraction.
    Materialart: Digitale Medien
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  • 98
    ISSN: 1432-1106
    Schlagwort(e): Key words Thyroid hormone ; RT-PCR ; p75 receptor ; trkA ; trkB ; trkC ; Septum ; Hippocampus ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Early postnatal application of thyroid hormones to rats results in morphological changes of the septo-hippocampal cholinergic and the hippocampal mossy fiber systems. Modulation in the expression of either neurotrophins and/or their receptors is postulated to be involved in these effects. In a recent study, we showed that, after thyroxine application, the mRNA expression of neurotrophins of the nerve-growth-factor (NGF) family is significantly upregulated both in septum and hippocampus. To test whether the neurotrophin receptors (the low-affinity neurotrophin receptor p75 and the specific high-affinity receptors trkA, trkB, and trkC) were also affected by hormone administration, newborn rats were treated daily with subcutaneous injections of thyroxine until postnatal day 12 (P12) at latest. Control animals received corresponding injections of saline. The pups were sacrificed at defined intervals from P9 to P14. The septal areas and the hippocampi were analyzed using the reverse-transcription polymerase chain reaction (RT-PCR) method for quantification of p75, trkA, trkB, and trkC mRNA levels. Analysis of variance over the total investigation period revealed no significant general increases of the gene expressions of either neurotrophin receptor, neither in the septum nor in the hippocampus, although previous results have shown marked changes in neurotrophin levels. On particular postnatal days, significant upregulation could be observed in hippocampus for trkB and trkC. From these and recent data, we conclude that modulation of neurotrophin expression rather than neurotrophin-receptor expression contributes to the morphological modifications within the hippocampal mossy fiber system and the septo-hippocampal cholinergic system.
    Materialart: Digitale Medien
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  • 99
    ISSN: 1432-1106
    Schlagwort(e): Key words Gabaculine ; NMR spectroscopy ; Microdialysis ; Amino acids ; Compartmentation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The aim of this work was to study the neurochemical effects in the brain of GABA-transaminase inhibition by systemic administration of gabaculine (100 mg/kg, i.a.) in the rat. In order to investigate neurotransmitter and related amino-acid compartmentation and metabolism, we have developed an original tool: the coupling, in vivo, on the same animal, of 2D COSY 1H-NMR spectroscopy with intracerebral microdialysis. The main result is a continuous increase in GABA levels, both in the intracellular compartment (up to 3000±450%; P〈0.001) and extracellular compartment (up to 808±82%; P〈0.01) at the sixth hour. The intracellular increase in GABA level became significant at the first hour following gabaculine administration, whereas the extracellular level increased as of the second hour, probably indicating that accumulation of GABA in nerve endings precedes its release in synaptic clefts. Moreover, the levels of the excitatory amino acids, glutamate and aspartate, were decreased both in the intra- and extracellular compartments, thus enhancing sedative effects of the drug. We also observed a decrease in the global energetic creatine-phosphocreatine pool, which also could be related to the sedative properties of gabaculine, measurable by the diminution of cortical electrical activity and mean arterial blood pressure. Finally, the coupling between 2D 1H-NMR spectroscopy and intracerebral microdialysis appears to be an original tool for investigating the cerebral metabolic effects induced by pharmacological agents, in situ, in living animals.
    Materialart: Digitale Medien
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  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 128 (1999), S. 309-314 
    ISSN: 1432-1106
    Schlagwort(e): Key words GABA ; Bromodeoxyuridine ; Proliferation ; Immunohistochemistry ; Retina ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The birthdates of GABAergic amacrine cells in the rat retina were investigated by immunocytochemistry using anti-GABA and anti-bromodeoxyuridine (BrdU) antisera. The ratio of co-localization of GABA to BrdU increased gradually from embryonic-day 13 (E13) and showed a peak value on E18 in the central retina and on E20 in the periphery. After birth, until postnatal-day 3 (P3), a few co-localized cells were observed in the inner nuclear layer (INL). However, in the peripheral retina, co-localized cells were observed in the INL and ganglion cell layer until P5. Our results suggest that the birthdates of GABA-immunoreactive cells vary, depending on cell-type and that there is a temporal lag in the GABA-immunoreactive cell production in the peripheral retina relative to the central retina.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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