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Biomedical subjects

K H Beyer

Publications and source records attributed to K H Beyer.

At least 37 records · Page 2Linked to original sources
PubMed1991

[Immunologic studies of benzodiazepine--the effect of structural characteristics on cross-reactivity].

The manufacturers' descriptions for immunoassays for the detection of benzodiazepines in urine suggest that all therapeutically used benzodiazepines are detected equally. It is unlikely that the different molecular structures do not influence the results of pertinent measurements. Therefore, the cross-reactivity of 35 benzodiazepines and benzodiazepine-metabolites was determined with the TDx-system. As compared to nordiazepam all compounds--except diazepam--had a reduced cross-reactivity. In order to get a TDx result equal to or exceeding 200 ng/ml nordiazepam-equivalents, high benzodiazepine concentrations in urine are required in some cases. These high concentrations are not obtained in the therapeutic range of application. These considerations can be applied to other immunoassays like RIA and EMIT.

Benzodiazepines↗
PubMed1990

Novel multivalent effects of pyrazinoylguanidine in patients with azotemia.

In patients with azotemia, urea excretion, urea clearance, and urea/creatinine clearance ratio were increased by pyrazinoylguanidine in a dose-related manner. Urine volume and excretion of sodium greater than chloride greater than potassium tended to increase during administration of pyrazinoylguanidine. Systemic arterial pressure declined while pyrazinoylguanidine was given at 300 or 600 mg b.i.d. for 3 days. At both doses pyrazinoylguanidine reduced plasma renin activity during the first 2 hours. Between days 1 and 3 only the high dose of pyrazinoylguanidine decreased plasma renin activity and plasma aldosterone levels. These findings with pyrazinoylguanidine are consistent with those of secretion of urea in human subjects across the renal tubules and indicate that this process is susceptible to pharmacologic alteration, even in the presence of severe renal insufficiency.

Adult↗
PubMed1988

[Fatal diltiazem poisoning].

The diagnosis at postmortem examination and the results of the chemical analysis in a case of a diltiazem intoxication are presented. Two metabolites were identified as desacetyldiltiazem and N-desmethyldiltiazem.

Alcoholism↗
PubMed1988

Active transport of urea by mammalian kidney.

With the aid of three basic organic compounds, 2-pyrazinoylguanidine, 3-amino-2-pyrazinoylguanidine, and 3,5-diamino-6-fluoro-2-pyrazinoylguanidine, urea was shown to be secreted by the renal tubules of the dog both from the lumen and into the lumen independent of urine flow.

Amiloride↗
PubMed1986

Fatal poisoning with selenium dioxide.

Two hours after suicidal ingestion of an unknown amount of selenium dioxide, a 17-year-old male was admitted to hospital with asystolia and apnea. Attempts at resuscitation failed and the patient was pronounced dead. Findings at autopsy included congestion of lungs and kidneys, diffuse swelling of the heart, and brain edema. The most impressive finding was an orange-brown discoloration of the skin and all viscera, probably due to hemolysis and/or pigmentation related to ingestion of selenium dioxide. Selenium blood and tissue levels were increased by a factor of 100-1000 as compared to normal. The highest concentrations were found in pancreas, spleen, liver, and adipose tissue. For elucidation of the chemical nature of selenium in tissues, a new analytical method which was based on carbon disulfide extraction was developed. Carbon disulfide is a good solvent for non-polar selenium compounds like elemental selenium and selenium disulfide, but not for polar compounds like selenite and selenoproteins. A major fraction of selenium in tissues was extractable by carbon disulfide, which seems to indicate the presence of elemental selenium and/or selenium disulfide. The color of these substances is red and orange, respectively. This might explain at least part of the discoloration of skin and tissues. In vitro experiments suggested that trace amounts of hydrogen selenide, which is an intermediate of selenite metabolism, probably induced hemolysis. For evaluation of the therapeutic value of hemoperfusion in selenium poisoning in vitro hemoperfusion experiments were performed, which revealed only a moderate effect on selenium blood levels.

Adolescent↗
PubMed1985

Sodium balance and blood pressure during high sodium ingestion in spontaneously hypertensive and Wistar Kyoto normotensive rats.

Objectives of this study were to compare natriuretic capability and arterial pressure elevation at high Na+ ingestion in male spontaneously hypertensive (SH) and normotensive Wistar Kyoto (WKY) rats at the young adult age of 16-19 weeks. 10 SH and 10 WKY male rats at this age were surgically implanted with arterial catheters. After a period of 10 days on low nutritionally adequate Na+ intake they were fed a high Na+ diet for a period of 1 week. Na+ retention (intake-output) on the high Na+ diet was substantial, but similar in both groups of rats. None of the animals displayed meaningful elevation of arterial pressure. Thus, the functional capacity of the young SH rat to excrete Na+ during excessive ingestion without elevation of blood pressure seems adequate as compared to normotensive rats, at least within the age range of 16-19 weeks.

Animals↗
PubMed1985

Metabolism of propallylonal.

Urinary metabolism of 5-beta-bromoallyl-5-isopropylbarbituric acid (propallylonal, Noctal), was studied in humans after an oral dose of 400 mg. About 25% of the dose was eliminated via kidneys within 48 h. Besides the unchanged drug, six metabolites could be detected. The main metabolic pathway is the hydrolysis of the beta-bromoallyl side chain to an acetonyl function (approximately 15%). The acetonyl function is subsequently reduced to the corresponding alcohol. Loss of water leads to aprobarbital which is partially oxidized to aprobarbital epoxide. Two further metabolites are formed by partial and complete oxidative degradation of the beta-bromoallyl side chain. In contrast to previously published results, no N-methylpropyllalonal could be detected. The plasma protein binding was determined by ultrafiltration (63%). Analysis of propallylonal in plasma and whole blood gave evidence for equal distribution between plasma and erythrocytes.

Barbiturates↗
PubMed1983

Sustained concurrent blood pressure and salt/water balance in unrestrained rats.

Methodology is detailed that provides sustained concurrent measurement of fluid volume and electrolyte intake and output with direct measurement of arterial pressure in unrestrained, unanesthetized spontaneously hypertensive rats (SHR). This method employs an all-Teflon arterial pressure conduction system, an air-pressurized infusion system, and standard rat metabolism cages. Blood pressure-salt/water balance studies comparing SHR unoperated, sham operated, and infused at several infusion rates and saline normalities indicated that infusion of 0.25 N saline at 0.5 ml/h sustained a patent system for high-fidelity recording of systolic and diastolic blood pressure without distortion of homeostasis over a 3-week period. Studies of basal SHR blood pressure and salt/water balance suggested that the SHR primarily used renal water-conserving mechanisms to dilute net acquired salt over an 11-day period. This methodology for sustained blood pressure measurement appears to represent a significant improvement for direct blood pressure measurement in unrestrained, unanesthetized rats.

Animals↗
PubMed1982

Chlorothiazide.

Explore the source record for details and available documents.

Animals↗
PubMed1981

The cosmetic ingredient review: a status report.

The cosmetic industry, with the advice of individuals familiar with food and drug safety assessment, set up a Cosmetic Ingredient Review panel of experts and an attendant staff in the fall of 1976, which began to function in July 1977. Its structure and role were carefully developed by a steering committee to assure the independence and credibility of the expert panel's deliberations and decisions and the ultimate publication of a final report on each of many ingredients. That report must conclude 1) that there is reasonable certainty that the ingredient is safe under conditions of use, 2) that it is unsafe, or 3) that the evidence is inadequate to make such a judgment. There is considerable variability in the adequacy of the safety assessments or the assessments of safety in the literature and unpublished reports on ingredients that have been reviewed to date.

Consultants↗
PubMed1978

Renal concentration gradients of salicylic acid and its metabolic congeners in the dog.

Salicylic acid and its principal metabolic product, salicyluric acid, are ultrafiltered at the glomeruli, secreted by the proximal segment and undergo back diffusion; the net effect being an accumulation of salicylates in the cortex. The back diffusion of salicylate is pH-sensitive (salicylurate is not) and its secretion is less sensitive than that of salicylurate to depression by probenecid. There was an increasing concentration gradient of these salicylates from outer cortex to innermost medulla. The clearance of salicyluric acid exceeded glomerular filtration rate even at very low urine flow and was not pH-dependent, so that total salicylate accumulation in the medulla was less affected by adjustment of urinary pH. Increasing perfusion of the nephron markedly reduced the inner medulla/cortical concentration ratios and segmental concentrations of salt and urea and reduced the cortical concentrations of salicylates. Diuresis may decrease the medullary concentration of salicylates, depending on the rate and duration of increased urine flow.

Animals↗