Search PubMed⌕ Search

Biomedical subjects

A Klein

Publications and source records attributed to A Klein.

At least 343 records · Page 19Linked to original sources
PubMed1987

The effect of linoleic acid on the sensitivity of human lymphocytes to cortisol and their capacity to catabolize the steroid.

We have shown previously that cortisol-sensitive lymphocytes (thymocytes) have a much lower capacity than cortisol-resistant cells to catabolize cortisol. In the present study, we attempt to demonstrate that inhibition of cortisol catabolism may make cortisol-resistant lymphocytes vulnerable to the steroid. Linoleic acid, which has the capacity to inhibit the catabolism of cortisol by lymphocytes, was used for this purpose. By using various concentrations of linoleic acid (20-60 micrograms/mL) we showed an inverse linear relationship between linoleic acid concentration and the rate of cortisol catabolism by lymphocytes. During this experiment which took 17 h the viability of cells did not change significantly (minimum viability 95%), even at the highest concentration of linoleic acid. Keeping the metabolism of cortisol at a level of 40% of that obtained by the control, by adding linoleic acid to lymphocyte cultures (50 micrograms/mL) and measuring the viability of the cells for a period of 3 days in the presence or absence of cortisol, we were able to show a rise in the death rate of the cells which started after 24 h of incubation owing to the presence of the steroid.

Humans↗
PubMed1987

Effect of a non-viral fraction of acquired immunodeficiency syndrome plasma on the vulnerability of lymphocytes to cortisol.

We have observed previously that the rate of cortisol catabolism by lymphocytes (CCL) was indicative of the vulnerability of these cells to cortisol. We attempted to ascertain whether cortisol-sensitive lymphocytes (e.g. thymocytes) metabolize cortisol at a different rate from cortisol-resistant cells and whether lymphocytes in which cortisol catabolism is inhibited become cortisol sensitive. The work was facilitated by the observation that an ethanol extract plasma from patients with acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC) had the capacity to inhibit CCL. The capacity of thymocytes to metabolize cortisol was found to be 11 times lower than that of peripheral lymphocytes. Inhibition of CCL with an ethanol extract of plasma from AIDS/ARC patients made the cells vulnerable to cortisol, causing them to die at a rate seven times greater than that of control samples. It is suggested that these findings may have important implications with regard to the nature of lymphocyte depletion in AIDS/ARC patients or in people at risk of developing the syndrome.

AIDS-Related Complex↗
PubMed1987

[Catheterization of the internal jugular vein using sonography].

Localisation of the internal jugular vein (IJV) by anatomical landmarks is common clinical practice. Specific complications associated with this technique are documented. Cannulation of the IJV is likely to be safer, when performed under direct vision, provided by a sonographic device. Following sonographic visualization, we have cannulated the IJV of 50 patients without complications. The tested device (Echokamera SSD-210 DX combined with the small-part-transducer UST-558-5, 5 MHz, 34 mm) proved useful in facilitating IJV cannulation.

Catheterization, Central Venous↗
PubMed1986

Immunocytochemical localization of component C of the methylreductase system in Methanococcus voltae and Methanobacterium thermoautotrophicum.

Antibodies were raised against homogeneous preparations of component C of the methylreductase system from Methanococcus voltae and Methanobacterium thermoautotrophicum. Cells of these organisms were fixed with paraformaldehyde and/or glutaraldehyde, sectioned, and labeled with antibodies and colloidal gold-labeled protein A. In M. voltae the gold particles were predominantly located in the vicinity of the cytoplasmic membrane. In rare cases a similar result was obtained also with M. thermoautotrophicum. However, in all but a few of the ultrathin sections of this bacterium, the label was randomly distributed in the cell interior. If one assumes a reliable fixation of all cell components, these results would suggest that the two distantly related methanogens studied have distinctive patterns for the localization of component C. The results with M. voltae are in agreement with recent findings that the methylreductase system is involved in the generation of a proton-motive force at the membrane.

Journal Article↗
PubMed1986

Effect of glucose, NADH and NADPH on cortisol metabolism by mononuclear cells.

Mononuclear cell preparations are capable of metabolizing cortisol to three metabolites which lack the immunosuppressive effect of their precursor. In the present study we noted a linear correlation, up to a point, between glucose concentration and the rate of human mononuclear cell cortisol metabolism in vitro. The mechanism by which glucose exerts its effect was investigated further. We observed that: the effect of glucose on mononuclear cell cortisol metabolism was not influenced by insulin; NADPH and NADH enhanced cortisol metabolism by disrupted cells, irrespective of whether the homogenates were dialysed or not; lactate and ATP inhibited mononuclear cell cortisol metabolism and almost all the glucose used was converted to lactate. It is concluded that mononuclear cell cortisol metabolism can depend on both nucleotides.

Adenosine Triphosphate↗
PubMed1986

Reducing the artifacts produced by impure antisera in immunoblots of low-molecular-mass proteins in urine.

Immunoblots of several urinary low-molecular-mass proteins can be very useful in investigations of pathological proteinuria. However, use of certain commercial antisera in such procedures leads to artifacts corresponding to nonspecific bands; e.g., immunoglobulins from nonimmunized rabbit serum may bind to human urinary proteins, and this binding is not inhibited by Triton X-100. We have developed a procedure to improve the specificity of detection of urinary low-Mr proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, by immunoblotting with commercial antisera: we treat the protein blot with a mixture of mercaptoethanol and sodium dodecyl sulfate before incubation with the first antiserum. This allows direct use of commercial antisera without prior absorption of contaminating antibodies.

Alpha-Globulins↗