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Biomedical subjects

A Klein

Publications and source records attributed to A Klein.

At least 415 records · Page 23Linked to original sources
PubMed1980

Detection of cancer in patients by reduced lymphocytic cortisol metabolism-enhancing effect.

A double-blind study was done on the plasma from 59 hospitalized patients to determine whether a diminished lymphocytic cortisol metabolism-enhancing effect among cancer patients could be used to distinguish them from persons with noncancerous diseases. Known concentrations of human lymphocytes from healthy donors were incubated with cortisol in media containing 50% phosphate-buffered saline (PBS) and 50% of one of the following additives: 1) homologous plasma (HP), 2) plasma from the patient being tested, or 3) additional PBS. Plasma in which the metabolism-enhancing effect was less than 70% of that obtained with HP was considered to be that of a cancer patient. Among the 19 patients known to have cancer, there were only two false-negative results, whereas among the 40 patients diagnosed as having noncancerous diseases, there were six false-positive results. Thus the test findings and the pathologic diagnosis were obviously correlated in approximately 90% of the patients.

Adolescent↗
PubMed1980

Preliminary results of the investigations of the cell surface membranes composition (proteins and sugars) in BHK-21, BHK-21/RSV and PR-RSH cell cultures.

The results of preliminary investigations concerned with protein and sugar composition of cell surface membranes of BHK-21, BHK-21/RSV and PR-RSH were described. The obtained results indicate on quantitative differences mainly in sugar content of the investigated cells. However differences of quantitative and qualitative composition of proteins of the BHK-21, BHK-21/RSV and PR-RSH were found.

Animals↗
PubMed1979

Cloning of the replication gene P of bacteriophage lambda: effects of increased P-protein synthesis on cellular and phage DNA replication.

A restriction fragment of lambdaDNA carrying the P gene was cloned in the high copy number plasmid RSF2124. Cells harbouring this new plasmid RSF2124/lambdaE complement lambdaPam80 phage. A lac promoter-operator region (lacP), produced by EcoRI digestion of plasmid pKB252, was inserted into RSF2124/lambdaE such that induction of the lac promoter by IPTG or lactose leads to increased production of the P gene product. A high amount of P protein in E. coli cells results in a slow inhibition of bacterial DNA synthesis, suggesting that the initiation reaction is blocked by P protein. Synthesis of lambdaDNA proceeds normally under these conditions. Nonsuppressing groPA15 mutant bacteria which are unable to support the replication of wild-type lambda (lambdawt), acquire the ability to replicate lambdaPam80 phage but not lambdawt when they are transformed with a plasmid carrying the lambdaP gene. When harbouring a plasmid containing the mutant Pamber 80 gene, groPA15 mutants are able to support the replication of lambdawt phage when infected at a high multiplicity. lambdaPam80 phage does not multiply in these cells.

Coliphages↗
PubMed1979

The influence of homologous plasma and fetal calf serum on human lymphocytic cortisol metabolism.

The influence of a) tissue culture medium (RPMI), b) homologous plasma (HP), and c) fetal calf serum (FCS) on lymphocytic cortisol metabolism was compared to that of phosphate buffered saline alone. RPMI was found to enhance the conversion rate 1.71 times, whereas HP and FCS enhanced it about 3.2 times. Raising the temperature of the HP and FCS to 100 degrees C before incubation reduced the enhancing effect to the level of that obtained with RPMI.

Blood↗
PubMed1979

Metabolism of cortisol by human thrombocytes.

A study was made in order to see whether human thrombocytes are capable to metabolize cortisol. Known concentrations of thrombocytes were incubated with 1.23H-cortisol and the products isolated and identified by t.l.c., paper chromatography, and derivations. Two metabolites were found to be produced by thrombocytes: 20beta-hydroxycortisol and tetrahydrocortisol. The enzymatic nature of the reactions was proved by (1) heat treatment (2) finding out NADPH to be a specific cofactor and (3) the dependence of the activity on the number of thrombocytes in suspensions.

Blood Platelets↗
PubMed1979

The influence of the non-dialysable sugar-peptide fraction from bovine blood plasma on the amino acid incorporation of BHK-21 normal and RSV transformed cells.

The non-dialysable sugar-peptide rich fraction of bovine blood plasma has been studied with regard to its influence on the amino acid incorporation of BHK-21 and BHK/RSV cells in vitro. The results indicate that the Nsp fraction contains a peptide factor(s) causing changes in activity for the protein and DNA synthethizing system in both the cell cultures examined. The biological activity of the factor(s) is regulated by interaction with blood serum components and this fact may play a leading role in its regulatory function.

Amino Acids↗
PubMed1978

Middle-sized ninhydrin-positive molecules in uraemic patients treated by repeated haemodialysis. II. Chief peptide constituents of the faction.

The fraction of middle-sized molecules obtained from haemodialysate by chromatography on Dowex 50W x 8 resolves upon thin-layer electrophoresis on Sephadex G-25 into nine ninhydrin-positive fractions and one staining only with tolidine reagent. All ten electrophoretic fractions give similar filtration profiles with Bio-Gel P-6 in the presence of SDS and 2-mercaptoethanol. The chief peptide components common to each electrophoretic fraction have molecular weight approx. 3000 and are especially abundant in lysine, glycine, glutamine acid and serine, while aromatic amino acids are in very low concentration.

Amino Acids↗
PubMed1978

Prevention of nitroprusside-induced cyanide toxicity with hydroxocobalamin.

To investigate hydroxocobalamin's role in preventing cyanide intoxication from sodium nitroprusside, we studied two groups of patients. One group received nitroprusside alone, and the other received nitroprusside and hydroxocobalamin. Red-cell and plasma cyanide levels were 83.44 +/- 23.12 and 3.51 +/- 1.01 microgram per 100 ml after nitroprusside alone and were 33.18 +/- 17.29 and 2.18 +/- 0.65 microgram per 100 ml after nitroprusside plus hydroxocobalamin. Acidosis developed in patients with red-cell cyanide levels higher than 75 microgram per 100 ml. When hydroxocobalamin infusion was stopped before sodium nitroprusside infusion was discontinued, blood cyanide levels and base deficit increased in a manner similar to that in the untreated group. The dose of nitroprusside used in each group did not differ statistically. These data show that hydroxocobalamin prevents cyanide transfer from red cells and plasma to tissue after nitroprusside metabolism, and thereby prevents cyanide toxicity from large intravenous doses of the drug.

Adult↗
PubMed1978

Initiation of lambda DNA replication in vitro promoted by isolated P-gene product.

The product of the P gene of bacteriophage lambda was isolated from heat-induced lambda-lysogenic Escherichia coli cells. It was found to bind to DNA, to be devoid of nuclease activity acting on double-stranded lambda DNA and of nicking/closing activity. Initiation of lambda DNA replication promoted by the P-gene product in a complementation assay in vitro was sensitive to rifampicin. Sedimentation analysis of the products and their hybridization to separated lambda DNA strands indicate that lambda DNA was formed in a reaction similar to ring-to-ring replication in vivo. The reaction was symmetric from the beginning, i.e. both lambda DNA strands were copied without delay.

Coliphages↗
PubMed1978

Cortisol metabolism in lymphocytes from cancer-bearing patients.

A study was conducted to determine the pattern of cortisol metabolism by lymphocytes obtained from four groups of subjects: 27 male and female patients suffering from various types of malignancy other than malignancy of lymphatic tissues; and 26 healthy male and female controls. Known concentrations of cells were incubated with 1,2-3H-cortisol and the products were isolated by thin-layer and paper chromatography. Three metabolites were found to be produced by lymphocytes from both normal and cancer-bearing patients: 20alpha-hydroxycortisol, 20beta-hydroxycortisol, and tetrahydrocortisol. Cells from the female control group were found to be more active than those from the male controls, while cells from cancer-bearing patients were markedly more active than the normal cells, regardless of sex. It is suggested that this finding of increased metabolism of cortisol by lymphocytes from patients with different types of malignancy other than lymphoma may provide the basis for a new diagnostic aid.

Adult↗
PubMed1978

Mycoplasma infection in pregnant rats: low viability of foetuses and newborn offspring.

The controversy regarding the possible role of genital mycoplasma infection in human reproductive failure gave rise to a study in which pregnant rats, previously shown to be of normal fertility, were inoculated 7-11 days after conception with either Mycoplasma arthritidis or an equal volume of sterile broth medium. Repeated observations during the course of pregnancy revealed several pathogenic effects. A statistically significant decrease was observed in the mean litter size of infected mothers. Furthermore, the offspring showed low viability at birth and, still more, at 10 days after birth. Our data are compatible with the hypothesis that genital mycoplasma infection plays a role in reproductive failure.

Animals↗
PubMed1978

Roles of bacteriophage lambda gene products O and P during early and late phases of infection cycle.

Ring-to-ring (early) replication of bacteriophage lambda DNA was blocked after heat inactivation of the P protein. Rolling circle (late) replication continued for several rounds at the rate reached when the temperature shift was carried out. The same differential effect was observed after inhibition of RNA or protein synthesis during the two different phases of replication. In contrast, inactivation of the O protein resulted in a fast stop of lambda DNA synthesis at early and late times after infection. The results were consistent with the following interpretations. (i) The lambda P gene product plays a role in the initiation of the ring-to-ring replication. (ii) Ring-to-ring replication continues parallel to rolling circle replication, possibly diminishing with time after infection. (iii) The O function is stable in and necessary for the structural integrity of an elongation complex. It is unstable in free form and probably released from such a replication complex after each round of replication at the ring-to-ring stage.

Chloramphenicol↗