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Biomedical subjects

K H Beyer

Publications and source records attributed to K H Beyer.

At least 19 recordsLinked to original sources
PubMed1992

Inhibition of urea transport across renal tubules by pyrazinoylguanidine and analogs.

In addition to glomerular filtration and passive back diffusion of urea, there occurs across the renal tubule bidirectional transport of urea inhibitable in one or both directions by specific analogs of pyrazinoylguanidine (PZG). Effect of PZG on the profiles of sodium and urea concentrations along the tubule (stop flow) are consistent with their independent transport. Inhibition of urea and sodium reabsorption by PZG is dose dependent. PZG does not inhibit potassium excretion.

Amiloride↗
PubMed1992

Pharmacokinetics of pyrazinoyl-guanidine, 3-aminopyrazinoyl-guanidine and their corresponding pyrazinoic acid metabolites in humans and dogs.

Pyrazinoylguanidine (PZG), 3-aminopyrazinoylguanidine (NH2PZG) and their pyrazinoic acid metabolites were measured by a new reverse-phase HPLC method in the serum of dogs and humans after administration of PZG, NH2PZG or 2-pyrazinoic acid (PZA). Kinetic properties of PZG and its principal metabolite, PZA, were studied in normal humans and also in azotemic patients, since PZG acts on renal tubules of patients with kidney failure to increase urea elimination. In humans and dogs, PZG was rapidly hydrolyzed to PZA. The serum half-life (t1/2) of PZG was 1 h. In turn, PZA was metabolized to 5-hydroxy-PZA, but no evidence appeared for conjugation of PZA with glycine. The apparent volume of distribution of PZG and its 3-amino analog, NH2PZG, exceeded that of total body water. In the dog the serum t1/2 for NH2PZG was twice that of PZG. Compared to PZG, NH2PZG and its metabolite, 3-aminopyrazinoic acid, were much stabler in vitro in serum and water.

Animals↗
PubMed1992

Pyrazinoylguanidine: antihypertensive, hypocholesterolemic, and renin effects.

In a single-blind, placebo-controlled study of 12 subjects diagnosed as having mild to moderate hypertension and hypercholesterolemia, pyrazinoylguanidine (PZG) in a dose of 600 mg twice daily for 4 weeks reduced systolic blood pressure and heart rate. Pyrazinoylguanidine also reduced diastolic pressures, but to a lesser extent. Pyrazinoylguanidine reduced total serum cholesterol and low-density lipoprotein (LDL). Regression analysis indicated a dose-dependent reduction of both total cholesterol and LDL by PZG, i.e., the higher the presenting serum concentration, the greater the reduction by PZG. The extent of the reductions produced by PZG in elevated cholesterols and LDLs was highly correlated (r = .949). Normal high-density lipoprotein levels were unchanged by PZG. Pyrazinoylguanidine increased 24-hour urine volume and urinary excretion of sodium. Serum Na+, K+, or Cl- concentrations were unaltered. Means for plasma aldosterone and renin activities tended to decrease, but these trends did not attain statistical significance. Pyrazinoylguanidine was well tolerated. An activity profile that includes antihypertensive effects as well as reduction in hypercholesterolemia without major impact on serum renin or electrolyte balance makes PZG an attractive candidate for the management of hypertension.

Aged↗
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↗
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↗
PubMed1977

[Pentazocine--an addiction problem? (author's transl)].

Pentazocine dependencies are rare. In a period of 5 years, 60 were notified. The majority of these were not dependent. Of 46 utilizable notifications, 38 were false, 5 had taken pentazocine only temporarily or not at all. 19 received it for chronic or recurrent pains, 13 were polytoxicomaniacs, and 1 patient could not be classified. Only 8 cases could be referred to as pentazocine-dependent. The dose for addicts and polytoxicomaniacs was 11 ampoules daily on the average, almost three times as high as that for patients with painful diseases. Pentazocine dependencies are considerably less of a problem than those of opiates used up to now: withdrawal symptoms are slight, neglect and social dangers need scarely be considered. "Users" generally only turn to pentazocine when a painful disease supervenes. Dependency practically never occurs with oral administration.

Adolescent↗
PubMed1977

A career or two.

Explore the source record for details and available documents.

Animals↗
PubMed1977

Saluretic and uricosuric effects of (6, 7-dichloro-2-methyl=1-oxo-2-phenyl-5-indanyloxy) acetic acid (MK-196) in the chimpanzee.

The saluretic and uricosuric responses elicited by a novel agent, MK-196, have been studied in a great ape, the chimpanzee. This agent is orally active at very low doses and has a prolonged duration of action. Probenecid does not appear to influence the saluretic and uricosuric properties of MK-196. Net tubular secretion of urate was reduced by MK-196. Urinary pH changes did not compromise the efficacy of this new agent. On a dose basis, MK-196 was more saluretic (and uricosuric) than ethacrynic acid or furosemide and possessed a longer duration of action. Because of the marked natriuresis caused by MK-196, some increase in potassium excretion occurred.

Animals↗