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Biomedical subjects

A Klein

Publications and source records attributed to A Klein.

At least 379 records · Page 21Linked to original sources
PubMed1984

Genome complexity of methanogenic bacteria.

The genome complexities of different methanogenic bacteria were investigated by using an optical method to study renaturation kinetics of single-stranded DNA. The observed genome sizes ranged from 1.0 X 10(9) to 1.8 X 10(9) daltons, which is a typical range for procaryotic cells. Melting profiles of the DNA of three methanogenic species from different families show fractions which have a higher A . T content than the average DNA of that species.

Adenine↗
PubMed1984

Diminished lymphocytic cortisol metabolism-enhancing effect in endogenous thyrotoxicosis.

A study was carried out to determine the effect on lymphocytic cortisol metabolism (LCM) of plasma from 62 patients with diffuse thyrotoxic goitre (DTG), 14 patients with toxic nodular goitre (TNG) and ten hypothyroid patients. Plasma of 33 healthy donors served as controls. A known concentration of human lymphocytes was incubated with cortisol in media containing 50% phosphate-buffered saline (PBS) and 50% of one of the following additions: (1) PBS, (2) homologous plasma (HP), (3) heterologous plasma, (4) plasma from DTG patients, (5) plasma from TNG patients, (6) plasma from hypothyroid patients, (7) PBS and HP to which L-thyroxine (T4) and triiodothyronine (T3) had been added separately and as a mixture up to a concentration ten times the normal, (8) boiled HP and (9) boiled DTG plasma. Plasma from hypothyroid patients gave an LCM-enhancing effect (LCMEE) similar to that of HP. The plasma of DTG and TNG patients had a markedly lesser effect on LCM than did HP. The T4 and T3 had no additional effect when added to PBS or HP. Boiling of HP and DTG plasma resulted in a similar decrease in LCMEE. The findings of this study raise the possibility of the existence of a factor inhibiting LCMEE in the plasma of thyrotoxic patients.

Adolescent↗
PubMed1984

Cancer and dysplasia of cervix in relation to reduced lymphocytic cortisol metabolism-enhancing effect.

In previous studies we found that the plasma of carcinoma patients shows a reduced capacity to enhance lymphocytic cortisol metabolism. In the present study this capacity was assessed in the plasma of patients suffering from cervical carcinoma (Ce. Ca.) and of patients suffering from cervical dysplasia (Ce. Dis.) regarded as being at high risk to develop cancer. 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 additions: 1) homologous plasma (HP), 2) plasma from the patients being tested or from healthy controls, or 3) additional PBS. The cortisol conversion rate was measured and compared with that obtained with lymphocytes immersed in HP. Previous findings showed that the plasma of cancer patients has a mean metabolism-enhancing rate 62% of that obtained with HP. In the present study the results were as follows: Ce. Ca., 60%; Ce. Dis., 70%: controls, 93%. The percentage of "cancer-positive" results were as follows: Ce. Ca., 91%; Ce. Dis., 45%; controls, 25%.

Female↗
PubMed1983

Multiple controls on the intracellular trapping of uridine.

Uridine uptake by mouse or hamster cells grown in conditions which support good growth is very sensitive to inhibition by cyanide and azide, at concentrations which only slightly reduce overall cellular ATP levels. Iodoacetate, when present alone, reduces uridine uptake only insofar as it reduces cellular ATP levels. At concentrations which by themselves do not affect uridine uptake, iodoacetate greatly reduces the sensitivity of uridine uptake to cyanide or azide. The effect of cyanide is on intracellular trapping of uridine and not on its transport into the cell. The specific effect of cyanide is confined to uridine and not found for the uptake of adenine, thymidine or 2-deoxyglucose. The effect is of rapid onset (within 2 min) and is rapidly reversible (also within 2 min). Phosphorylation of uridine in homogenised cells or in Triton X-100-permeabilised cells is unaffected by cyanide. The data are interpreted in terms of a model in which intracellular trapping of uridine is subject to multiple controls, including one regulated by some factor requiring intact functioning of the mitochondrion. These multiple control systems interact synergistically to affect trapping of uridine by the intact cell.

Adenosine Triphosphate↗
PubMed1983

Structure and function of mutants in the P gene of bacteriophage lambda leading to the pi phenotype.

The location of 14 independently isolated spontaneous pi A and pi B point mutants in the lambda P gene and their base exchanges were determined. It was found that the pi B mutation is one unique type mapping close to other pi A mutants. The number of possible pi A mutation sites could be estimated. The mutation sites are distributed asymmetrically in the gene. The N-terminal half of the protein is unchanged. It is assumed to be required for the interaction with the lambda O protein. The P protein can be changed by substitution of a limited number of amino acids at the C-terminus. All functional proteins of this type have pi character. pi proteins do not appear to have altered intracellular levels or stabilities as compared to wild-type P protein. The plating characteristics of our mutants on two groP- mutants located in the dnaJ and dnaK genes, respectively, are strikingly different.

Bacteriophage lambda↗
PubMed1983

Basal cell carcinomas, gastrointestinal carcinomas, and ulcerative colitis in relation to the disappearance of a plasma factor.

Our previous findings have shown that the plasma of cancer patients lacks a factor (LCMEF) that is characterized by its ability to enhance lymphocytic cortisol metabolism. In the present study we have examined whether this phenomenon also appears in patients suffering from basal cell carcinoma, a seldom metastasizing disease, and in patients with ulcerative colitis regarded to be at high risk of developing cancer. 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 additions: 1) homologous plasma, 2) plasma from the patients being tested, or 3) additional PBS. Previous findings showed that the plasma of cancer patients has a mean metabolism-enhancing rate of 62% of that obtained with homologous plasma. In the present work the results were as follows: basal cell carcinomas--98%, gastrointestinal carcinomas--63%, ulcerative colitis--95%, and healthy donors--90%. The results with regard to cancer patients show that lack of LCMEF does not characterize basal cell carcinoma and ulcerative colitis. Hence, it is possible that the disappearance of LCMEF 1) does not characterize ulcerative colitis as long as a malignant tumor does not appear and 2) does not characterize seldom metastasizing disease (basal cell carcinoma).

Adenocarcinoma↗
PubMed1983

Injectable collagen: a clinical overview.

Injectable bovine collagen is extremely effective in the correction of contour defects of the skin due to scarring and age-induced rhytides and folds. The rate of adverse reactions is low. Of 5,109 patients treated in clinical trials, 1.3 percent experienced temporary local inflammation at the site of injection. Techniques of injection and proper patient selection are presented. Repeat implantations at intervals of six to twenty-four months are often required to maintain full correction of cutaneous contour defects.

Cicatrix↗
PubMed1983

Isolation of the homogeneous constituents from non-diffusible sugar-peptide (NSP) fraction originating from bovine plasma. III. The method of isolation and partial characterization of the four peptide constituents.

The purification of four different peptides from the NSP fraction of bovine plasma, using: organic solvents extraction, column Sephadex G-50 filtration, thin-layer Sephadex G-25 electrophoresis in 5 M guanidine hydrochloride and thin-layer Bio-Gel P-6 electrophoresis methods was described. The molecular weights of the isolated peptides and their amino acid composition were determined. The dose-dependent effect two of the four peptides on 3H-thymidine incorporation into BHK-21 and BHK/RSV cells was described. The results support previous observations that the NSP fraction contains a peptide growth prometing factor and a potent peptide growth inhibitor. The possible physiological role of the peptide growth inhibitor was discussed.

Amino Acids↗
PubMed1983

First isolation step of a plasma factor which enhances lymphocytic cortisol metabolism and which is reduced in cancer patients.

Our previous findings show that cancer patients' plasma lacks a factor (LCMEF) which is characterized by its ability to enhance lymphocytic cortisol metabolism. In the present study, using the dialysis method, we tried to evaluate the size of that factor. Plasma of healthy donors (HP) was dialyzed against water. Human lymphocytes from healthy donors were incubated with cortisol in media containing buffer (PBS) and one of the following additions: 1) dialyzate, 2) dialyzed HP (DP), 3) reconstituted HP (DP + P). The cortisol conversion rates were compared with that obtained with untreated HP and with PBS. The results showed no significant differences among the conversion rates obtained with HP, dialyzate, and reconstituted HP. Dialyzed plasma, however, showed a significantly lower rate, which was equal to that obtained with PBS. This implies that the factors are smaller than 10,000 daltons.

Humans↗
PubMed1982

Replication of lambda dv DNA in vitro.

Exogenous lambda dv DNA was replicated in extracts prepared from E. coli cells carrying plasmids with inducible lambda O and /or P genes. Extracts from cells carrying only one of the two lambda replication functions complement each other in this reaction. The reaction further requires ribonucleotide triphosphates, an ATP regenerating system, DNA gyrase and RNA polymerase functions. Density labelling of the superhelical reaction products results in hybrid density indicating that one complete round of replication has taken place in vitro.

Bacteriophage lambda↗
PubMed1982

Case report 213.

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Diagnosis, Differential↗
PubMed1982

Isolation of the homogeneous constituents from non-diffusible sugar-peptide (NSP) fraction originating from bovine plasma--I. Method of disruption of a sugar-peptide aggregate.

1. High molecular weight sugar-peptide aggregate contains 84--92% of sugar-peptide compounds of the whole non-diffusible sugar-peptide (NSP) fraction obtained from bovine blood plasma by the two-step dialysis method. 2. The aggregate can be resolved into various numbers, dependent on conditions, of electrophoretic homogeneous bands, which appeared to be heterogeneous in thin-layer chromatography on MN-Cellulose. 3. Electrophoresis in 5 M guanidine-hydrochloride allows the disruption of the aggregate and isolation of seven chromatographic and electrophoretic homogeneous constituents with different molecular weights and chemical characters.

Animals↗
PubMed1982

Isolation of the homogeneous constituents from non-diffusible sugar-peptide (NSP) fraction originating from bovine plasma--II. The influence on cell growth of BHK-21, BHK/RSV and PR-RSH cells in vitro.

1. The sugar-peptide aggregate isolated from the NSP fraction of bovine blood, added in concentration 20 microgram/ml, decrease of [3H]thymidine incorporation and cell proliferation of BHK-21 and BHK/RSV cells in vitro to approx. 25% of untreated control. 2. Two of four peptide constituents of the aggregate show distinct and extremely different effects on cell growth in vitro. The effects of peptide D mol. wt 5000-6000 is characteristic for peptide growth factors, while the peptide G mol. wt 1200-1800 decreases rapidly the growth of all investigated kinds of cells to 8-16% relative to untreated control. 3. The NSP fraction contains also two non-peptide constituents, which inhibit the growth of Rous sarcoma virus transformed cells to a statistically significant degree and have no effect on the growth of BHK-21 cells.

Animals↗