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Biomedical subjects

V G Oberholzer

Publications and source records attributed to V G Oberholzer.

15 recordsLinked to original sources
PubMed1989

Familial salivary gland insensitivity to aldosterone: a variant of pseudohypoaldosteronism.

Two male siblings presented in infancy with hyponatraemia. Levels of plasma renin activity and aldosterone were elevated. Sodium supplementation was necessary to maintain normal sodium balance. Urinary sodium concentration and renal epithelial exchange between sodium and potassium were normal; however, salivary sodium concentrations were markedly elevated with sweat sodium levels being in the upper normal range. Excess salivary sodium loss accounted for sodium depletion in these cases who present a new variant of pseudohypoaldosteronism associated with normal renal sodium transport.

Aldosterone↗
PubMed1988

Lactosylceramide in inflammatory bowel disease: a biochemical study.

A simple technique for isolating lipids from small pieces of tissue was applied to mucosal biopsies and samples of resected intestine from patients with inflammatory bowel disease. Scanning densitometry of two dimensional chromatograms showed increased concentrations of the membrane associated glycosphingolipid lactosylceramide in Crohn's disease, on comparison with ulcerative colitis (p less than 0.01), or controls (p less than 0.01). This indicates either that normal glycosphingolipid metabolism is altered, or that a novel source of lactosylceramide is present in the inflamed mucosa of patients with Crohn's disease.

Adolescent↗
PubMed1988

Ginseng--is there a use in clinical medicine?

Panax ginseng occupies an important place among the tonic remedies of Oriental medicine. Pharmacological investigations show that crude ginsenosides can increase non-specific resistance of an organism to various untoward influences. The effects of purified derived derivatives have only recently become better studied in immunological and cell growth studies in animals and in man. This has now provided some evidence to suggest that ginseng is a drug that contains many derivatives with different pharmacological properties, which could be useful in clinical medicine.

Animals↗
PubMed1987

In-vitro antibiotic inactivation by mammalian cell and killed bacterial preparations.

Inactivation of a range of antibiotics acting at different points in the metabolism of the bacterial cell was detected by estimating the MIC and MBC in the presence of liver and other tissue preparations. High temperature treatment and sonication of liver cells increased their ability to inactivate antibiotic action. This treatment would have almost completely destroyed enzyme activity, which was, therefore, not thought likely to be the cause of the phenomenon. The loss of antibiotic activity may be related to "protein binding" and a dialysis experiment showed that penicillin binding with liver homogenate was very much greater than with human albumin. It may be that increased disruption of tissue cells by physical methods exposes more active binding sites which reduces the bioavailability of antibiotics. Some degree of binding specificity was indicated in experiments in which DNA was shown to block antibiotics acting primarily on DNA--related synthesis and RNA blocked antibiotics acting on RNA--related metabolism. Suggestions are made for the cause of failure of antibiotic treatment in certain clinical situations.

Animals↗
PubMed1987

Inhibition of bovine liver lysine-ketoglutarate reductase by urea cycle metabolites and saccharopine.

Lysine-ketoglutarate reductase was purified 675-fold from bovine liver mitochondria. Product inhibition studies gave results similar to those reported for this enzyme extracted from other sources. Inhibition studies with L-citrulline exhibited mixed inhibition patterns. No inhibition of the partially-purified enzyme by ammonium salts was detected; in contrast, marked inhibition of the enzyme by ammonium was apparently observed in crude liver homogenates. This was probably due to depletion of NADPH and/or 2-oxoglutarate in the assay mixture as a result of conversion of ammonium to glutamate by glutamate dehydrogenase. A similar explanation could account for the high levels of lysine observed in humans with urea cycle disorders.

Ammonia↗
PubMed1978

3-Amino-2-piperidone in the urine of patients with hyperornithinemia.

3-Amino-2-piperidone, a delta-lactam of ornithine, has been detected in the urine of a number of patients with hyperornithinemia. The distinctive yellow colour formed with a ninhydrin-cadmium reagent should help in the detection of hyperornithinemia by urinary chromatography.

Adolescent↗
PubMed1978

Acute neonatal and benign citrullinaemia in one sibship.

Citrullinaemia was diagnosed in an infant who died at age 8 days. The clinical picture was of the disease in its acute neonatal form. A sib has a blood citrulline of 100 times normal and about 10% of normal argininosuccinic acid synthetase activity in cultured fibroblasts. Clinically he is normal with an IQ of 94 on the Wechsler Intelligence Scale for Children.

Amino Acid Metabolism, Inborn Errors↗
PubMed1976

Increased excretion of N-carbamoyl compounds in patients with urea cycle defects.

Increased urinary levels of N-carbamoyl-beta-alanine, and also, on occasions, of N-carbamoylaspartate, were observed in patients with ornithine carbamoyl-transferase (EC 2.1.3.3) deficiency, argininosuccinate synthetase (EC 6.3.4.5) deficiency and argininosuccinate lyase (EC 4.3.2.1)deficiency, but not in a patient with carbamoylphosphate synthase deficiency. The relevance of these findings to the diagnosis of urea cycle defects is discussed.

Alanine↗
PubMed1976

Microscale modification of a cation-exchange column procedure for plasma ammonia.

A column cation-exchange resin procedure for plasma ammonia was modified to require only 100 mul of plasma per determination. Mean analytical recovery of standard from resin (six samples) was 98% (range, 94-100%) as compared to a mean of 63% (range, 58-70) for nine samples when a batch cation-exchange procedure was used. Absorbance was proportional to sample concentration up to 800 mumol/liter. Analytical recovery of standard from plsma (six samples) was complete (mean, 103%; range, 90-113). Thirteen aliquots of a specimen of fresh plasma from a single adult individual gave a mean value of 20 mumol/liter (range, 11-26). The mean plasma venous ammonia concentration for 27 adults was 16 mumol/liter (range, 0-39), and for 15 newborns it was 60 (range, 34-102). Values for capillary plasma measured at the same time were higher, and we discuss possible explanations for this. Values are given for infants and children from one month to 14 years of age. Effects of storage time and temperature on plasma ammonia concentration are discussed.

Adolescent↗
PubMed1975

Increased pyroglutamic acid levels in patients on artificial diets.

Increased plasma and urine levels of pyroglutamic acid were found in 4 patients being fed the low-lactose food Nutramigen. Pyroglutamic acid was detected and estimated by a variety of methods, and the merits of the techniques used and their application in a screening programme are discussed.

Carbohydrate Metabolism, Inborn Errors↗