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Biomedical subjects

O Zinder

Publications and source records attributed to O Zinder.

At least 19 recordsLinked to original sources
PubMed1992

Preferential release of epinephrine by glycine from adrenal chromaffin cells.

Isolated adrenal chromaffin cells were used as a model for the release of catecholamines from adrenergic nerve endings. In this study we used an HPLC technique to determine the effects of acetylcholine and glycine on norepinephrine and epinephrine release. The amount of catecholamine released in response to glycine was 22% less than that released by acetylcholine. However, while the norepinephrine-to-epinephrine ratio was 1.6 after stimulation with acetylcholine, it was 0.6 after stimulation with glycine. This suggests that glycine preferentially affects epinephrine secretion as compared to acetylcholine, which preferentially releases norepinephrine. This differential effect could be of physiological importance considering our recent demonstration of a functional high-affinity chloride-gated glycine receptor on adrenal chromaffin cells.

Acetylcholine↗
PubMed1991

Effects of the glycine prodrug milacemide (2-N-pentylaminoacetamide) on catecholamine secretion from isolated adrenal medulla chromaffin cells.

1. Milacemide (2-n-pentylaminoacetamide) is a glycine prodrug which readily crosses the blood brain barrier and increases brain glycine and glycineamide. In vitro and in vivo studies, with numerous tissues, including adrenal chromaffin cells, have clearly shown that the formation of the latter metabolites is exclusively mediated by monoamine oxidase B for which milacemide is a substrate. 2. Milacemide, glycineamide and glycine caused a time- and dose-dependent release of catecholamines from bovine isolated chromaffin cells. 3. Milacemide (10(-4) M) induced catecholamine release was roughly 30% of that initiated by acetylcholine (10(-4) M), the natural secretagogue. 4. The combined effects of milacemide (10(-4) M) and acetycholine (10(-4) M) on catecholamine secretion from chromaffin cells is additive, suggesting that milacemide does not act through the normal nicotinic receptor release mechanism. 5. The release of catecholamines from chromaffin cells in response to milacemide (10(-4) M) was partially inhibited by the selective MAO-B inhibitors (-)-deprenyl (10(-7) M) and AGN 1135 (10(-6) M). This indicates that the MAO-B derived metabolites, glycineamide and glycine, contribute to the secretion of catecholamines as does milacemide itself. 6. It is apparent that release of catecholamines by glycine is mediated by its uptake into the cells since [3H]-glycine uptake and catecholamine release showed a highly significant correlation (r = 0.96).

Acetamides↗
PubMed1991

Catecholamine determination in sequential urine voiding: a method for detecting pheochromocytoma in patients without elevated urinary catecholamines.

The biochemical diagnosis of pheochromocytoma is based on the demonstration of increased amounts of catecholamines, or catecholamine metabolites, in 24-h urine samples. In patients whose 24-h urine catecholamines are within normal limits, and in whom short duration catecholamine elevations are suspected, timed urine collections have been used to detect these elevations. In this study, determination of catecholamines in sequential urine voidings and consideration of their relative values are suggested as a further method to detect pheochromocytomas, especially in cases without extended elevation of urinary catecholamine levels. The use of this method is demonstrated in three cases in which pheochromocytoma would not otherwise have been proven by laboratory determination.

Adrenal Gland Neoplasms↗
PubMed1989

Guidelines (1988) for training in clinical laboratory management. International Federation of Clinical Chemistry (IFCC) Education Division and International Union of Pure and Applied Chemistry (IUPAC) Clinical Chemistry Division Commission on Teaching of Clinical Chemistry.

Trainees in laboratory medicine must develop skills in laboratory management. Guidelines are detailed for laboratory staff in training, directors responsible for staff development and professional bodies wishing to generate material appropriate to their needs. The syllabus delineates the knowledge base required and includes laboratory planning and organisation, control of operations, methodology and instrumentation, data management and statistics, financial management, clinical use of tests, communication, personnel management and training, and research and development. Methods for achievement of the skills required are suggested. A bibliography of IFCC publications and other material is provided to assist in training in laboratory management.

Administrative Personnel↗
PubMed1989

Prediction of the presence of ovarian cancer at surgery by an immunochemical panel: CA 125 and copper-to-zinc ratio.

Preoperative levels of the trace elements copper and zinc, in addition to the level of the known marker CA 125, were studied in sera of 32 patients undergoing exploratory laparotomy for suspicion of ovarian cancer and in sera of 49 patients with the diagnosis of ovarian cancer prior to second-look operation. Most patients (63/81) had stage III or IV disease. CA 125 levels greater than 35 U/ml, copper levels greater than 1.5 mg/liter, and zinc levels less than 0.9 mg/liter were considered pathologic. An immunochemical panel composed of CA 125 serum level and ratio of copper to zinc (Cu/Zn) (normal less than 1.65) was found to be most sensitive (98%) in predicting the existence of ovarian cancer before laparotomy, and its overall predictability was 89%. In 14 of 14 patients (100%) who had complete primary surgery for ovarian cancer, the panel was correct in predicting no tumor at second-look operation. In 13 of 14 patients (93%) who had incomplete primary surgery but had no clinical evidence of disease prior to second-look operation, the panel was correct in predicting ovarian cancer. In these two groups of patients, second-look operation could have been replaced by the results of the immunochemical panel.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1989

International Federation of Clinical Chemistry Education Division and International Union of Pure and Applied Chemistry Clinical Chemistry Division Commission on Teaching of Clinical Chemistry. Guidelines (1988) for training in clinical laboratory management.

Trainees in laboratory medicine must develop skills in laboratory management. Guidelines are detailed for laboratory staff in training, directors responsible for staff development and professional bodies wishing to generate material appropriate to their needs. The syllabus delineates the knowledge base required and includes laboratory planning and organisation, control of operations, methodology and instrumentation, data management and statistics, financial management, clinical use of tests, communication, personnel management and training, and research and development. Methods for achievement of the skills required are suggested. A bibliography of IFCC publications and other material is provided to assist in training in laboratory management.

Chemistry, Clinical↗
PubMed1989

International Federation of Clinical Chemistry (IFCC), Education Division. Guidelines (1988) for training in clinical laboratory management.

Trainees in laboratory medicine must develop skills in laboratory management. Guidelines are detailed for laboratory staff in training, directors responsible for staff development and professional bodies wishing to generate material appropriate to their needs. The syllabus delineates the knowledge base required and includes laboratory planning and organisation, control of operations, methodology and instrumentation, data management and statistics, financial management, clinical use of tests, communication, personnel management and training, and research and development. Methods for achievement of the skills required are suggested. A bibliography of IFCC publications and other material is provided to assist in training in laboratory management.

Chemistry, Clinical↗
PubMed1988

Thiamin status of the offspring of diabetic rats.

Erythrocyte transketolase activity and thiamin pyrophosphate effect were examined in the offspring of streptozotocin-diabetic rats. Thiamin reserve was found to be significantly reduced in litters of untreated diabetic rats as compared to control and to insulin-treated diabetic rats. Supplementation of the untreated diabetic dams throughout pregnancy with oral thiamin was associated with a significantly improved thiamin status of the litters. We conclude that, due to enhanced fetal glucose turnover during diabetic gestation, a fetal thiamin deficiency state may evolve; this condition can be remedied with maternal thiamin supplementation.

Animals↗
PubMed1987

Prostatic ejaculate in assigned males with 46,XX congenital adrenal hyperplasia.

Two assigned males with 46,XX congenital virilizing adrenal hyperplasia due to 11 beta-hydroxylase deficiency reported an ejaculation of thick fluid. Chemical analysis revealed that the fluids bore a resemblance to normal prostatic fluids. Extreme virilization in utero seems to have produced both complete virilization of external genitalia and development of a prostate.

Adrenal Hyperplasia, Congenital↗
PubMed1986

Natural killer cell activity in post-necrotic cirrhotic patients as related to hepatitis-B virus infection and plasma zinc levels.

In view of the suggested physiological role of natural killer (NK) cells in immunosurveillance and defence against viral infections, we have investigated the relationship between hepatitis B virus (HBV) infection and NK activity against K-562 cells in patients with post-necrotic cirrhosis. Overall, the NK activity in cirrhotic patients did not differ from age- and sex-matched controls. However, cirrhotic males with evidence of HBV infection with or without HBs antigenemia tend to have lower NK activity than controls. Cirrhotic males without evidence of HBV infection do not differ from controls. Such a trend was not observed in the female cirrhotic patients examined. In addition significantly reduced NK activity was observed in cirrhotic patients with low plasma zinc levels. This relationship is of interest because of the known association between zinc deficiency and various immunodeficiencies.

Adolescent↗
PubMed1986

Unconjugated hyperbilirubinaemia in hypertrophic pyloric stenosis, an enigma.

In a search of features that might be relevant to the understanding of the hyperbilirubinaemia of infants with hypertrophic pyloric stenosis (HPS), we examined the duodenal fluid in 11 infants with this condition. Four (36%) had an unconjugated bilirubin level above 2.5 mg/dl in the serum. Levels of electrolytes, bicarbonate, liver function tests and cholesterol were similar in the jaundiced and the non-icteric infants. Examination of duodenal fluid for pH, concentration of bilirubin, bile salts, electrolytes and beta-glucuronidase levels also did not disclose any significant differences between the HPS patients and the controls. Bacterial culture of the fluid yielded similar results in both groups. We may conclude that the unconjugated hyperbilirubinaemia observed in some patients with HPS is not associated with overgrowth of bacteria, changes in glucuronidase levels, pH, electrolytes or biliary obstruction.

Bilirubin↗