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Biomedical subjects

Y Bentur

Publications and source records attributed to Y Bentur.

48 records · Page 3Linked to original sources
PubMed1989

The effects of mannitol diuresis on digoxin and phenobarbital handling by the kidney: implications for tubular reabsorption and secretion of the cardiac glycoside.

The effect of mannitol diuresis on the renal clearance of digoxin and phenobarbital was studied in dogs. Mannitol diuresis significantly increased the clearance of digoxin and the ratio digoxin: inulin clearances (from 0.7 +/- 0.2 to 1.1 +/- 0.25). The increase in phenobarbital: inulin clearance ratio was significantly higher than the increase in the digoxin: inulin clearance ratio (4.9 fold vs 1.66 fold) (p less than 0.005). Mannitol diuresis did not significantly affect inulin clearance, nor digoxin protein binding during the experimental period while there was a significant increase in PAH clearance. Significant correlations were found between urine flow rate and digoxin renal clearance or digoxin: inulin clearance ratio. The increase in the ratio drug: inulin clearance with diuresis correlated inversely with the initial ratio; animals with more predominant net reabsorption had a higher increase in ratio. These studies suggest that the mannitol-induced increase in digoxin clearance stems from a combination of increased renal blood flow enhancing digoxin secretion, and increased urine flow rate inhibiting its reabsorption. We conclude that urine flow rate and renal blood flow are important determinants of the renal clearance of digoxin, independent of GFR. Any study assessing the effect of pathophysiological states or drug interactions on digoxin renal clearance must control for these factors.

Animals↗
PubMed1989

A high-performance liquid chromatographic method for the measurement of deferoxamine in body fluids.

A high-performance liquid chromatography method for the analysis of deferoxamine (DFO) in 100 microliters of serum or plasma is described. The procedure involves the addition of the internal standard ciprofloxacin to the sample, followed by ultrafiltration to remove protein. The ultrafiltrate is then directly injected into the chromatography system. Separation is achieved using a reverse-phase mu Bondapak C18 column and a ternary solvent system (sodium phosphate:acetonitrile:methanol) running at 2.0 ml/min. Assay time is 10 min, and chromatograms show no interference from coadministered drugs during this period of time. Coefficients of variation were found to be less than 5%, and analytical recovery of DFO was 85%. Validation experiments in an experimental dog model and in patients with iron overload demonstrate that the method is appropriate for studying the pharmacokinetics of DFO in thalassemic patients receiving drug for the treatment of chronic iron overload.

Adolescent↗
PubMed1988

An unusual skin exposure to copper; clinical and pharmacokinetic evaluation.

Skin exposure to copper is rare and has been described only with copper sulfate. A case of skin exposure to copper after an explosion of copper azide is presented. The amount of copper absorbed by this route was estimated to be 7.7 mg. Calculated distribution volume was 2.02 I/kg, half-life was 167.4 days and clearance was 0.0058 ml/min/kg. The authors also demonstrated metallic copper to be radiopaque, in contrast to copper salts. It is suggested that copper may be absorbed from the skin even if it is in the metal form. Careful clinical follow up as well as serial determinations of serum copper should guide the need for chelation therapy.

Accidents, Occupational↗
PubMed1987

Meso-2,3-dimercaptosuccinic acid in the diagnosis and treatment of lead poisoning.

Lead poisoning remains one of the hazards of industrialized civilization. CaNa2 EDTA and dimercaprol, the usual therapeutic measures, have many side effects and can be given by parenteral route alone. The authors present a case of chronic lead poisoning caused by ingestion of contaminated flour ground in a primitive flour mill. The diagnosis was confirmed by the CaNa2 EDTA provocative test. Dimercaptosuccinic acid (DMSA) was given orally as a further provocation and resulted in an 11-fold increase in urinary lead excretion. A 5-day course of treatment with DMSA was instituted, during which symptoms abated, urinary lead excretion increased and the blood lead level decreased. No side effects were noticed. There has been no relapse over several months of follow-up. The authors conclude that the oral use of DMSA is effective, safe and convenient both as a provocative test in establishing the diagnosis of lead poisoning and as a therapeutic tool.

Adult↗
PubMed1985

Effect of metoclopramide--a dopaminergic blocker and endogenous cortisol on TSH secretion in critically ill men.

In 17 critically ill men, low levels of FT4, TT4, TT3 and elevated levels of rT3 and cortisol were found. In spite of the low levels of circulating thyroid hormones, TSH levels of the critically ill men were significantly lower than those of the control group, with no correlations to the high cortisol levels. After iv injection of metoclopramide (MCP), a dopamine (DA) receptor blocker, the TSH and prolactin (Prl) increments in the critically ill patients were significantly lower than in the controls. No correlation was observed between basal cortisol levels and integrated TSH response to MCP. It is suggested that increased DA tone or high cortisol levels are not responsible for the lower basal TSH levels and for the blunted TSH or Prl responses to MCP in the critically ill. High levels of cortisol may be responsible for the altered TT4 peripheral metabolism to TT3 and rT3 in these patients.

Adult↗
PubMedDate not supplied

Deferoxamine (desferrioxamine). New toxicities for an old drug.

Iron is an essential element for body homoeostasis, but there is no effective mechanism for elimination of an excess of this mineral. Deferoxamine (desferrioxamine) is currently the treatment of choice for iron overload states from both acute iron intoxication and transfusion-dependent anaemias. The pharmacokinetics of deferoxamine are confounded both by its ability to chelate endogenous and exogenous iron and by the laboratory techniques used for its determination. Its iron-complex (ferrioxamine) has different pharmacokinetic properties. Because of its effectiveness, the use of deferoxamine is becoming more common, involving long term and high dose regimens. As a result of this, more and more toxicities that were not known in the past have been described and characterised. The most serious of these include hypotension, renal insufficiency, neurotoxicity, growth retardation and opportunistic infections: some of these side effects may be attributed to or aggravated by ferrioxamine. The pharmacological and toxicological literature on deferoxamine, and possible mechanisms for its toxicity, are reviewed and discussed.

Animals↗