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Biomedical subjects

B Halpern

Publications and source records attributed to B Halpern.

At least 37 records · Page 2Linked to original sources
PubMed1980

Antenatal diagnosis of glutaric acidemia.

Two pregnancies at risk for glutaric acidemia were monitored. In one, in which the fetus was not affected, glutaric acid was not detected in the amniotic fluid at amniocentesis (15 weeks) and the glutaryl-CoA dehydrogenase activity of cultured amniotic cells was normal. In the other, a marked elevation of glutaric acid in the amniotic fluid, together with deficiency of glutaryl-CoA dehydrogenase in amniotic cells, prompted termination of the pregnancy, and studies on the abortus confirmed the diagnosis of glutaric acidemia. Glutaric acidemia, is, thus, another inborn error of metabolism which can be diagnosed in utero.

Acyl Coenzyme A↗
PubMed1980

Measurement of sodium valproate in serum by direct-insertion chemical-ionization/mass spectrometry.

To quantitatively determine sodium valproate, we use a stable isotope-labeled internal standard and chemical-ionization/mass spectrometry, without prior chromatographic separation. The technique is rapid, simple, sensitive, and provides for the routine analysis of 100 microL of serum with good within-day and day-to-day precision. The technique also allows for the simultaneous determination of phenobarbital, mephobarbital, carbamazepine, primidone, and phenytoin.

Carbamazepine↗
PubMed1979

In vitro effect of dopamine and pimozide on human chorionic gonadotropin secretion.

In human placental explants cultured in vitro, dopamine inhibited human chorionic gonadotropin (hCG) secretion into the culture media. In the control flasks, the level of hCG secretion was 751 +/- 215 mIU/gm of tissue. When 1 mM of dopamine was added, hCG levels decreased to 321 +/- 57.6 mIU/gm of tissue (n = 6, P less than 0.1)--5 and 10 mM of dopamine significantly inhibited hCG secretion. In contrast, 1 mM of pimozide enhanced hCG secretion by 1.8-fold compared to control levels (1,707 +/- 343 versus 3,117 +/- 0.005). This in vitro effect on hCG is similar to the effect of dopamine and pimozide on hCS secretion by placental explants.

Chorionic Gonadotropin↗
PubMed1979

Studies on a child suspected of having a dficiency in 3-hydroxy-3-methylglutaryl-Co A lyase.

The urine of a child who presented with hyperammonemia was found to contain elevated levels of 3-hydroxy-3-methylglutaric acid, 3-methylglutaconic acid and 3-methylglutaric acid. An increased excretion of these organic acids has been reported previously in a child with 3-hydroxy-3-methylglutaryl-CoA lyase deficiency. Enzyme studies using cultured fibroblasts from this patient, however, indicated that the 3-hydroxy-3-methylglutaryl-CoA lyase activity was not markedly reduced.

Acyl Coenzyme A↗
PubMed1979

Dicarboxylic aciduria: the response to fasting.

The urine of a child who presented with an episode of a disease resembling Reye's syndrome was found to contain large quantities of the dicarboxylic acids adipic and suberic acids, as well as the glycine conjugate of suberic acid, suberyl glycine. A variety of other dicarboxylic acids, both saturated and unsaturated, were also found in the urine at the time of the attack. It was found that the excretion of these unusual metabolites could be markedly increased by fasting for periods of greater than 10 h. These results indicate that the patient may have a defect in fatty acid oxidation which becomes clinically significant during periods of prolonged fasting.

Adipates↗
PubMed1979

Effect of Corynebacterium parvum on hemopoietic stem-cell kinetics.

The intravenous administration of 548 microgram of killed Corynebacterium parvum (C. parvum) into C57BL mice leads to a significant decrease in the number of bone-marrow colony-forming-units in spleen (CFUs) as early as 12 h after the injection of the bacterium. This decrease persisted in varying degrees for 3 weeks. After an initial fall at 24 h, the splenic CFUs exhibited a rapid expansion and reached values 10 times higher than the control range on the ninth day. A significant rise in the number of circulating CFUs, reaching a first peak at 2 h and a second one on the fifth day, was also observed. The proliferative status of femoral CFUs was increased at 48 and 72 h, while that of splenic CFUs presented a significant increase only 48 h after the injection of C. parvum. The sequence of events which were observed in these experiments indicates that an accelerated migration of hemopoietic stem cells from bone marrow to spleen via the blood circulation has to take place.

Animals↗
PubMed1979

The identification of 3-keto-2-methylvaleric acid and 3-hydroxy-2-methylvaleric acid in a patient with propionic acidemia.

Two abnormal metabolites, 3-keto-2-methylvaleric acid and 3-hydroxy-2-methylvaleric acid, have been identified and quantitated in the urine of a child with propionic acidemia. These metabolites may be produced as a result of the self-condensation of propionyl-CoA. Data are presented to show that the unusual ketone, 3-pentanone, which has been observed previously in the urine of patients with propionic acidemia, is produced as a result of the decarboxylation of 3-keto-2-methylvaleric acid.

Gas Chromatography-Mass Spectrometry↗
PubMed1979

Abnormal deoxyribose metabolites in the urine of a child with a possible new inborn error of metabolism.

The urinary extract of a child investigated because of strabismus was found to contain large amounts of a compound which was identified using gas chromatography/mass spectrometry as 2-deoxyerythropentono-1,4-lactone. This lactone has not been observed previously in urinary extracts. When ion-exchange chromatography was used to isolate the organic acids from urine, the major peaks obtained by gas chromatography were shown to be 2-deoxyerythropentonic acid, 2-deoxyerythropentono-1,5-lactone and 2-deoxyerythropentono-1,4,lactone. Another abnormal metabolite, 2-deoxyribitol, was also excreted by the patient although this compound could not be detected in the urine of normal children. It is proposed that these unusual compounds accumulate in the urine of this child as a result of a defect in the catabolism of 2-deoxyribose.

Deoxyribose↗
PubMed1979

The protective effect of some phenothiazine derivatives against streptolysin O.

1 Chlorpromazine (Cpz) and promethazine (Pmz) protected mice against lethal doses of streptolysin O (SLO) given intravenously. Three other phenothiazine derivatives had similar but lesser effects. 2 The protective effect developed slowly; maximal protection was obtained 4 h after subcutaneous injection of Cpz and Pmz. 3 The haemolytic activity of SLO in vitro was also inhibited by Cpz.

Animals↗
PubMed1978

Simultaneous determination of diphenylhydantoin, mephobarbital, carbamazepine, phenobarbital and primidone in serum using direct chemical ionization mass spectrometry.

A quantitative method for the simultaneous determination of five anticonvulsants in serum has been developed using chemical ionization mass spectrometry without prior chromatographic separation. The technique was shown to be rapid, simple and sensitive, allowing the routine analysis of 50 microliter of serum with good within-day and day-to-day precision.

Anticonvulsants↗
PubMed1978

Failure of somatostatin to affect human chorionic somatomammotropin and human chorionic gonadotropin secretion in vitro.

The effect of somatostatin (SRIF) on human chorionic somatomammotropin (hCS) secretion was studied in human placental explants cultured in vitro. In the experimental flasks, SRIF was added in a concentration of 10, 100, and 1000 ng/ml media; hCS levels measured by RIA were not different from those found in the control flasks. In separate experiments, we investigated the action of SRIF on hCG secretion by a human malignant choriocarcinoma cell line maintained in tissue culture. SRIF (1000 ng/ml) did not inhibit basal or dibutyryl cAMP-induced stimulation of hCG secretion. These results suggest that somatostatin does not suppress hCS or hCG release in vitro from normal or malignant trophoblast, respectively.

Bucladesine↗