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  • 1
    ISSN: 1432-1106
    Keywords: Key words Focal cerebral ischemia ; Photothrombosis ; Reperfusion ; Spontaneous recanalization ; Cerebral blood flow ; Edema ; Penumbra ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  In clinical thromboembolic stroke, spontaneous late recanalization is a common feature, but one which has been very sparsely studied experimentally. This study aimed at enabling the study of spontaneous reperfusion and exploring its consequences by modifying a recently developed photothrombotic-stroke model that focuses on the region-at-risk located within an ischemic ring-locus. The exposed crania of male Wistar rats (280–340 g) were subjected to a ring-shaped (5.0 mm outer diameter and 0.35 mm thick) laser-irradiation beam (514.5 nm; 0.89 W/cm2) for 2 min simultaneously with intravenous erythrosin B (17 mg/kg) infusion for 30 s. Transcardial carbon-black perfusion experiments revealed a ring-shaped cortical perfusion deficit at 4 h post-irradiation, which progressively increased at 10, 24, and 48 h, at which time the whole region-at-risk was pale with single distal branches of the middle cerebral artery being extensively narrowed, but not occluded. At 72 h, spontaneous reperfusion was observed in the region-at risk, which was even more pronounced at 7 and 28 days. Cortical cerebral blood flow (cCBF), measured by laser-Doppler flowmetry, was distinctly reduced at 2 min post-irradiation and further decreased slightly during 4 h of recording to ca. 24% of baseline values at the ring locus and 40% in the region-at-risk. In the region-at-risk, cCBF flow values were 23–30% of the baseline at 24–48 h post-irradiation, followed by a relative cCBF increase to 71 and 77% at 72 and 96 h post-irradiation. Brain water content in the ischemic part of the cortex increased steadily from 4 to 48 h post-irradiation; at 72 h, it leveled off and returned to control values at 7 days. In conclusion, by employing a laser beam in the shape of a thin ring, critically sustained cCBF reduction was followed by late, consistent spontaneous reperfusion in the region-at-risk in this novel photochemically induced stroke-in-evolution model.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1106
    Keywords: Key words Cerebral ischemia ; focal ; Photothrombosis ; Evolution of ischemia ; Penumbra ; Ischemic cell change ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The photothrombotic ring stroke model with sustained underperfusion followed by late spontaneous reperfusion (Gu et al. 1999) was employed to study its morphological consequences. The exposed crania of adult male Wistar rats were subjected to a ring-shaped laser irradiation beam simultaneously with intravenous erythrosin B infusion. The ischemic volume was calculated from serial sections throughout the ischemic lesions at 4, 10, 24, 48, and 72 h and 7 days and 28 days after irradiation. The ischemic volume, expressed as a percentage of the ipsilateral hemispheric volume, increased steadily from 4 to 10 to 24 h to reach its maximum value at 48 h after irradiation; at 3 days, 7 days, and 28 days, the ischemic volume was reduced to 75%, 24%, and 22% of the value at 48 h. Evaluation of ischemic volumes at different anteroposterior levels revealed that the reduced ischemic volume at 72 h and later was mainly due to morphological restoration in the centrally located, nonirradiated region at risk. An initial enlargement and development of cystic coagulation necrosis was observed in the cortical areas corresponding to the ring lesion itself. In the region at risk, a gradually deteriorating neuropil and nerve cell morphology were observed over time, with maximum severity at 48 h postirradiation. At this time, most laminae II and III neurons in the region at risk exhibited eosinophilia and pyknosis but no incrustations, with small islands of less damaged neurons randomly scattered. At 72 h and up to 28 days after irradiation, these cell characteristics were no longer observed and the region at risk was well populated with neurons that had a chiefly unremarkable cytological appearance. Neuronal counts in the central part of the region at risk were performed; no significant difference in neuronal density was observed between sham-operated controls and at 28 days after irradiation. In conclusion, the consistent, late spontaneous reperfusion coincided with remarkable tissue recovery as assessed morphologically in the region at risk. The data suggest that nerve cell repair may occur even after the detection, by conventional morphological methods, of prolonged critical ischemic neuronal damage in the setting of acute ischemic stroke.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1041
    Keywords: spironolactone ; thiazides ; digitalis ; congestive heart failure ; arterial hypertension ; skeletal muscle potassium ; serum potassium ; skeletal muscle magnesium ; serum magnesium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of adding spironolactone (Aldactone) on muscle electrolytes was studied in 48 patients with arterial hypertension and/or congestive heart failure who had received conventional diuretic treatment, including a potassium supplement, for more than 1 year. After 6 months on spironolactone 100 mg/day as well as the original conventional diuretic therapy, there was a significant increase in both skeletal muscle potassium and magnesium. At the same time these parameters decreased in the control group. In the spironolactone group there was also a significant increase in the mean serum potassium and creatinine levels. There was a significant fall in blood pressure in the spironolactone-treated group.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 33 (1988), S. 577-579 
    ISSN: 1432-1041
    Keywords: diuretics ; triamterene ; magnesium ; potassium ; plasma ; skeletal muscle ; hydrochlorothiazide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects on plasma and skeletal muscle electrolytes of the combination of triamterene 37.5 mg and hydrochlorothiazide 25 mg daily were studied in 19 patients on prior long-term (〉1 year) diuretic therapy for arterial hypertension and/or congestive heart failure. A further 20 patients fulfilling the same admission criteria were used as controls. Blood samples and skeletal muscle biopsies were taken before the study and after 6 months on therapy. The diuretic-treated group had a significant increase in skeletal muscle potassium and magnesium after 6 months on therapy as compared to the controls. Thus, the combination of triameterene and hydrochlorothiazide appeared effective in preserving the cellular content of potassium and magnesium on a long-term basis in the type of patient studied.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Chromatography B: Biomedical Sciences and Applications 415 (1987), S. 261-274 
    ISSN: 0378-4347
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Chromatography B: Biomedical Sciences and Applications 415 (1987), S. 275-288 
    ISSN: 0378-4347
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1435-1463
    Keywords: Human brain ; post-mortem ; agonal state ; lactic acid ; pH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Measurement of the frontal cortex and the medulla oblongata pH at autopsy revealed that those brains from individuals who died after long terminal phase had lower pHs than those who died quickly. These low pHs (pH 6.0–6.5) corresponded to lactic acid concentrations (20–25 mM) which are known to be neurotoxic. The cerebrospinal fluid pH and blood pH correlated with the cortical pH. The significance of these observations to the study of the biochemistry and histology on post-mortem human brain tissue and their possible clinical relevance are discussed.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neural transmission 67 (1986), S. 275-285 
    ISSN: 1435-1463
    Keywords: Post mortem ; 3H-acetylcholine ; release ; physostigmine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A technique was developed, which made it possible to study thein vitro release of3H-acetylcholine (3H-ACh) from human post mortem brain tissue, collected with short post-mortem delay (2,5–22 hours), both from controls and patients with Alzheimer's disease (AD/SDAT). The tritium (3H) release was investigated during potassium stimulation, and AD/SDAT cortical slices were found to release a decreased amount of3H compared to control brain slices. Physostigmine, 10−5 and 10−4 M, has no significant effect on the release of3H from control slices, while physostigmine 10−4 M increased the evoked release from AD/SDAT brain slices over threefold, nearly to the control level.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1573-3017
    Keywords: fish ; Oryzias latipes ; Poecilia reticulata ; laboratory ; toxicological pathology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: This paper presents an overview of the studies carried out in small laboratory fish species to investigate the usefulness of histopathology as a tool in aquatic toxicology. The studies were performed with medaka (Oryzias latipes) and guppy (Poecilia reticulata) that were exposed to a variety of environmental contaminants for one and three months. Besides the measurement of routine toxicological parameters, total body histopathology was carried out. The data are summarized and evaluated in view of their contribution to the knowledge of toxicology, the specific responsiveness of animals and tissues, and the application in ecotoxicology. It is concluded that histopathology of (small) fish exposed to environmental contaminants may provide useful information as to target organs and mechanism of action: moreover, this technique can be more sensitive than routine parameters.
    Type of Medium: Electronic Resource
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