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Biomedical subjects

N Grossowicz

Publications and source records attributed to N Grossowicz.

13 recordsLinked to original sources
PubMed1979

Prevalence and causes of anemia in elderly hospitalized patients.

The prevalence and causes of anemia have been studied in 104 patients over 60 years of age admitted to a general medical ward in Jerusalem. In males and females, mean hemoglobin levels were about 1 g less than in the corresponding groups of healthy younger controls. A primary nutritional anemia could not be implicated in any of the 15 patients with hemoglobins below 11 g/dl. The most important causes of anemia were chronic renal failure, metastatic carcinoma, gastrointestinal bleeding, and infection. Conversely, in diseases with no adverse effect on erythropoiesis such as chronic ischemic heart disease, hypertension and diabetes, hemoglobin levels were equal to those of the younger controls. These findings indicate that although diminished serum iron and RBC folate levels may occasionally be found in elderly subjects, nutritional deficiency is seldom responsible for anemia in this age group in Israel- and anemia when present is often the manifestation of a chronic underlying disease.

Adult↗
PubMed1979

Improved lysozyme assay in biological fluids.

We describe a simple, rapid, sensitive, and highly reproducible assay for lysozyme, with use of concentrated cell suspensions of Micrococcus lysodeikticus in Tris-buffered glycerol/water (40/60 by vol), pH 7.5. Stored at -20 degrees C, the cells' susceptibility to lysozyme remains unaltered over long periods. Almost identical concentration curves were obtained with different aliquots of the same preparation during eight months. Lysozyme activity was reflected in the decrease in absorbance of the reaction mixture after incubation for 15 min at 37 degrees C. Concentrations of egg-white lysozyme as low as 0.02 mg/L can be accurately assayed.

Biological Assay↗
PubMed1977

Relationship between culture density and catabolite repression of an inducible aliphatic amidase in a thermophilic bacillus.

A direct correlation between the absorbance of a thermophilic bacillus and specific amidase activity was observed, which was found to depend on the cell density of the culture rather than on the time of contact of the culture with the inducer. Dilution of high density cultures caused the specific amidase activity to decrease. Environmental factors such as pH, concentration of inducer or degree of aeration, and level of NH+4 and glutamate had no effect on amidase synthesis. The decrease in amidase activity upon dilution could not be ascribed to destruction by oxygen or by inactivation or decay. Several lines of evidence suggest that catabolite repression is responsible for the phenomenon described. Succinate-grown cultures gave a stronger dilution effect thatn glutamate-grown cells. The mutant strain E-21, relatively resistant to catabolite repression, did not show the characteristic dilution effect nor the direct correlation between absorbance and specific amidase activity.

Acetamides↗
PubMed1977

Effect of a polyene antibiotic on growth and phosphate uptake by Candida albicans.

The polyene antibiotic, amphotericin, inhibited phosphate uptake in Candida albicans more strongly than it inhibited growth. Cultures grown from an inoculum of young (2 h) cells were more affected than those inoculated with old (24 h) cells. Thus, the polyene displays a double effect on C. albicans (and presumably on other eukaryotic cells): it interferes with membrane sterols and also inhibits synthesis of a factor (or factors) during growth. Whether this factor(s) interferes with the uptake of the polyene antibiotic or neutralizes its effect by reacting with it remains unsolved.

Amphotericin B↗
PubMed1976

Regulatory control and function of alanine dehydrogenase from a thermophilic bacillus.

L-alanine dehydrogenase, (L-alanine:NAD+ oxidoreductase (deaminating), EC 1.4.1.1) synthesis in a thermophilic bacillus was found to be subjected to regulatory control. Addition of L- and D-alanine and L-serine to cultures growing in the presence of either succinate or pyruvate, induced an accelerated synthesis of the alanine dehydrogenase enzyme. Synthesis of the enzyme was dependent on the presence of inducer during growth and was arrested by addition of glucose. Catabolite repression by glucose was abolished by limiting the ammonium concentration during growth. The apparent Km values of the substrates involved in alanine dehydrogenase activity are as follows (M): NH4+, 4-10(-2); pyruvate, 5-10(-4); NADH, 6-10(-5); L-alanine, 3.1-10(-3) and NAD, 2-10(-4). Alanine dehydrogenase activity was measurable at temperatures below the minimal growth temperature (at 25 degrees C) and the highest activity was found at 65 degrees C; heat denaturation occurred at 80 degrees C.

Alanine↗
PubMed1976

Effect of calcium ions on growth and metabolism of Saccharomyces carlsbergensis.

Addition of calcium ions increased 2- to 3-fold the growth of Saccharomyces carlsbergensis 2I in a minimal glucose-containing medium. The minimal concentration enhancing growth was 25 to 50 mug/ml CaCl2. Other divalent and trivalent cations tested, except for strontium ions, did not duplicate the calcium effect. Actively growing and dividing cells took up 45Ca2+, while resting yeast cells did not. The radiocalcium taken up was incorporated into newly synthesized structural material, presumably into the membrane protein.

Barium↗
PubMed1976

Fractionation of serum transcobalamins on charged cellulose filters.

A simple and rapid fractionation procedure of the three transcobalamins, TCI, TCII, and TCII, of human serum was achieved by filtration through a stack of charged cellulose filters composed of one cellulose-nitrate and three DEAE-cellulose (DE-81) disks. A reaction mixture containing microliter amounts of serum was incubated with excess of 57Co B12 of high specific activity, diluted with 0.1 M sodium borate buffer (pH 8.5), and passed through the filter stack by applying vacuum. Under these conditions TCII is selectively and quantitatively adsorbed to the cellulose-nitrate filter while both TCI and TCIII adsorb to the DE-81 filters. In the second step TCIII is selectively desorbed from the latter filters by a 0.05 M monopotassium phosphate solution of pH 4.6. Using sera of different distribution of transcobalamins the data obtained were comparable to those determined by the more laborious methods employing DE-52 column chromatography combined with procedures to remove TCII.

Blood Proteins↗
PubMed1975

Nutritional survey in an iron- and folate-deficient population.

A high prevalence of folate and iron-deficiency anemia was found in women and children of Kiryat Shmoneh, an Upper Galilee community. Malnutrition was assumed to be partially responsible for these deficiencies. To verify this assumption, a detailed nutrition survey was carried out in 30 families, comprising 232 individuals in this community. A low overall caloric intake was found in 30% of the population studied. The dietary folates consumed were much below the recommended dietary allowance in all subjects. In over 60% of the subjects investigated, the daily iron intake was also below the recommended allowance. These data support the role of malnutrition in the development of folate and iron deficiencies in the community studied.

Adolescent↗
PubMed1975

Purification and properties of glutamate dehydrogenase from a thermophilic bacillus.

A 250- to 300-fold purification of a nicotinamide adenine denucleotide phosphate (NADP)-dependent glutamate dehydrogenase (GDH, E.C. 1.4.1.4) with a yield of 60% from a thermophilic bacillus is described. More than one NADP-specific GDH was detected by polyacrylamide gel electrophoresis. The enzyme is of high molecular weight (approximately 2 X 10-6), similar to that of the beef and frog liver GDH. The pI of the thermophilic GDH is at pH 5.24. The enzyme is highly thermostable at the pH range of 5.8 to 9.0. The purified GDH, unlike the crude enzyme, was very labile at subzero temperatures. An unidentified factor(s) from the crude cell-free extract prevented the inactivation of the purified GDH at -70 C. Various reactants of the GDH system and D-glutamate also protected, to some extent, the enzyme from inactivation at -70 C. From the Michaelis constants for glutamate (1.1 X 10-2M), NADP (3 X 10-4M), ammonia (2.1 X 10-2M), alpha-ketoglutarate (1.3 X 10-3M), and reduced NADP (5.3 X 10-5M), it is suggested that the enzyme catalyzes in vivo the formation of glutamate from ammonia and alpha-ketoglutarate. The amination of alpha-ketoglutarate and deamination of glutamate by the thermophilic GDH are optimal at the pH values of 7.2 and 8.4, respectively.

Acetone↗