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Biomedical subjects

B C Halpern

Publications and source records attributed to B C Halpern.

17 recordsLinked to original sources
PubMed1991

Down man on the field.

Rapid evaluation and treatment of playing-field injuries can save a patient's life and prevent further injury. These outcomes are possible if trained personnel, who are familiar with athletic injuries, are present. This article presents basic procedures for adequate preparation, step-by-step assessment, and management of emergencies on the field, including cardiovascular emergencies; anaphylaxis; central nervous system injuries; abdominal and pelvic injuries; eye, ear, and nose injuries; and extremity injuries.

Anaphylaxis↗
PubMed1981

Urinary excretion levels of unconjugated pterins in cancer patients and normal individuals.

Urinary excretion levels of seven unconjugated pterins in healthy individuals and in cancer patients, most of whom were undergoing chemotherapy, were measured utilizing a newly developed high-pressure liquid chromatographic system. Excretion of pterins in the control group appears to be under strict metabolic control as the values obtained were confined within a small range. When the mean excretion levels in control subjects were compared with those in cancer patients, we found a significant increase in the excretion of xanthopterin, neopterin and pterin and a significant decrease in isoxanthopterin by cancer patients. Biopterin levels, on the other hand, were found only slightly but not significantly increased, whereas pterin-6-carboxylic acid and 6-hydroxymethylpterin were found to be excreted in approximately equal amounts in both groups. Urinary excretion levels of pterins were monitored for a period of nine months in a patient being treated with chemotherapy for metastatic ovarian carcinomatosis. We found that the excretion pattern of pterins appeared to correlate with the clinical status of the patient. These results indicate that a definite imbalance in pterin, and possibly folate metabolism, is associated with the presence of malignant diseases.

Adult↗
PubMed1980

Quantitative determination of pterins in biological fluids by high-performance liquid chromatography.

During our continuing study of pteridine metabolism, the need arose for a more rapid and quantitative determination of pterins in biological fluids. By adopting and modifying previously developed techniques, we have obtained a rapid and sensitive method that allows the simultaneous determination of eight different pterins in human urine and blood. When examined over a 10-day period, the levels of pterins excreted by a normal individual averaged the following values expressed in picomoles per mg of creatinine: biopterin, 9104; neopterin, 6018; xanthopterin, 6561; pterin, 1136; isoxanthopterin, 636; pterin-6-carboxylate, 483; and 6-hydroxymethylpterin, 315. Moreover, 6-hydroxymethylpterin and pterin-6-carboxaldehyde were detected for the first time in the blood of normal individuals.

Chromatography, High Pressure Liquid↗
PubMed1978

Folate and pterin metabolism by cancer cells in culture.

Malignant cells grown in culture excrete into their growth medium a folate catabolite that can be seen as a blue-fluorescent region on paper chromatograms of such media. This folate catabolite has now been identified by paper chromatography, thin-layer chromatography, and combined gas chromatography-mass spectrometry as 6- hydroxymethylpterin and not as pterin-6-carboxaldehyde as previously reported. Moreover, when pterin-6-carboxaldehyde was added to the growth medium of logarithmically growing malignant cells, it was primarily reduced to 6-hydroxymethylpterin. In contrast pterin-6-carboxylate was the principal product formed from added pterin-6-carboxaldehyde by normal established cell lines in culture. These results have been interpreted as indicative of a possible mechanism of folate catabolism in malignant cells. Folic acid or another folate derivative is oxidatively cleaved at the C-9-N-10 bond to yield pterin-6-carboxaldehyde as one of the products. This derivative is subsequently reduced to 6-hydroxymethylpterin, which is excreted into the growth medium.

Cells, Cultured↗
PubMed1977

Pterin-6-aldehyde, a cancer cell catabolite: identification and application in diagnosis and treatment of human cancer.

Active folic acid degradation with the formation pterin-6-aldehyde is a previously undescribed characteristic of cancer cells in tissue culture. Neither normal adult epithelial and fibroblastic cells nor human amniotic cells nor mouse embryonic fibroblasts degrade folic acid to a measurable degree. Twenty-nine patients whose diagnoses were not revealed until after the test of their first morning urine for pterin-6-aldehyde was completed were studied for the presence or absence of pterin-6-aldehyde by thin-layer chromatography. Pterin-6-aldehyde was found in the urine at about 300 nmol/ml or greater only in those 13 patients with a tissue diagnosis of cancer. When the cancer was totally resected, the pterin-6-aldehyde was no longer found in the urine postoperatively. Pterin-6-aldehyde is not found in the urine of healthy patients at this level of detection unless their diets are supplemented with folic acid.

Adolescent↗
PubMed1975

Fractionation of mucopolysaccharides by countercurrent distribution in aqueous polymer two-phase systems.

A new procedure for the fractionation of mucopolysaccharides based upon differences in their partition behavior in aqueous polymer two-phase systems has been devised. Systems containing dextran, poly(ethylene glycol), trimethylamino-poly(ethylene glycol), potassium bromide and sodium phosphate buffer were employed. Countercurrent distributions were performed with a miniature countercurrent distribution device designed especially for use with aqueous polymer two-phase systems. An advantage over the widely used procedures involving precipitation of mucopolysaccharides as their quaternary ammonium detergent complexes is that the countercurrent distribution pattern of a particular mucopolysaccharide is not affected by the simultaneous presence of other mucopolysaccharides. Preliminary distributions of labelled mucopolysaccharides isolated from the cells and culture medium of monolayer cultures of rat tumor cells demonstrate that the procedure is particularly well suited for the fractionation of very minute quantities of mucopolysaccharides.

Cell Line↗
PubMed1975

New approach to antifolate treatment of certain cancers as demonstrated in tissue culture.

The selective toxicity of antifolates for a variety of cancers can be improved, as illustrated by the combined administration of N5-methyltetrahydrofolate and methotrexate in tissue culture. When a variety of neoplastic cell types characterized by a deficiency of vitamin B12-dependent N5-methyltetrahydrofolate methyltransferase (5-methyltetrahydropteroyl-L-glutamate:L-homocysteine S-methyltransferase, EC 2.1.1.13) and normal adult cells are grown in media containing methotrexate and either N5-methyltetrahydrofolate or N5-formyltetrahydrofolate, not only is the selective toxicity of methotrexate demonstrated, but the advantage of using N5-methyltetrahydrofolate in place of N5-formyltetrahydrofolate is also revealed. The implications and applications of this particular combination in the treatment of human cancer are discussed.

Animals↗
PubMed1970

Reversal of malignant transformation by tumor DNA.

Walker-256 carcinosarcoma cells grown in tissue culture medium containing inhibitory DNA prepared from the tumor are shown to have an unaltered growth in vitro, but a diminished capacity to produce malignant tumors on injection into the rat. Coincident with this change in virulence is the induction of tRNA methylase inhibitors in these malignant cells. Within days after the DNA is removed from the growth medium, the tRNA methylase inhibitors disappear and the oncogenicity reappears.

Animals↗
PubMedDate not supplied

Effect of methionine replacement by homocystine in cultures containing both malignant rat breast carcinosarcoma (Walker-256) cells and normal adult rat liver fibroblasts.

When malignant W-256 rat breast carcinosarcoma cells are mixed with an equal number of normal adult rat liver fibroblasts and allowed to grow in a medium containing sufficient L-methionine and an excess of vitamin B12 and of folic acid, the malignant cells outgrow the normal cells, and within 2 weeks the tissue culture flasks contain only neoplastic cells. However, when ample DL-homocystine or homocysteine replaces methionine in the medium containing the same amount of vitamin B12 and folic acid, and seeded with the same type and number of malignant and normal cells, the malignant cells die and the normal cells thrive. Substantiating this conclusion are the results of injections into rats of comparable numbers of cells from each group after 3 weeks of growth in tissue culture. Fatal malignancies are produced by the homocystein-cultivated cells.

Animals↗
PubMedDate not supplied

Observations on blood pressure measurements in high-school athletes.

The purpose of this study is to identify possible evidence of hypertension in athletic adolescents. In addition to sex and age, the effects of various physical factors that may influence blood pressure are measured. The data were collected from the annual screening physicals of local high-school athletic program participants. Nine of the 11 measured physical factors account for 10 percent to 20 percent of the variability in blood pressure measurements. These include age, weight, height, pulse, quadriceps girth, heel cord flexibility, jump reach, hang time, and grip strength. These variables are incorporated into formulae that adjust the range of "normal" values of systolic and diastolic blood pressure to reduce the effects of these confounding factors, thereby increasing the accuracy of the "normal" or "hypertensive" determination for each individual.

Adolescent↗