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Biomedical subjects

K Brendel

Publications and source records attributed to K Brendel.

At least 145 records · Page 8Linked to original sources
PubMed1980

A simple procedure for the purification of bovine fibrin from clotted blood by the use of detergents.

A rapid and simple procedure for the preparation, directly from clotted whole blood, of bovine fibrin free of cell membrane contaminants is described. The procedure exploits the ability of detergents to solubilize and extract cell membrane proteins from homogenized clot fragments. The non-denaturing detergents, TX-100 and DOC, used in sequence, or the denaturing detergent, SDS, used alone, proved equally effective. The resulting fibrin has the solubility properties and the subunit composition on SDS gels of highly cross-linked fibrin.

Animals↗
PubMed1980

Rabbit glomerular and tubular basement membranes: morphology and differential solubilization.

Rabbit glomeruli and tubules were obtained by retrograde perfusion of magnetite into the lower aorta as previously described for the isolation of rat glomeruli. In addition, an alternative method of separating rabbit glomerular and tubular basement membranes from a single renal cortex preparation was developed. These preparations, which represent the Triton X-100-insoluble material, were extracted in sequence with deoxycholate, dodecyl sulfate in the presence and absence of 2-mercaptoethanol at 8 degrees C and again in the latter at 100 degrees C. The polypeptides solubilized at each step of this sequence were characterized by electrophoresis. The final extract consisted almost exclusively of red-staining, presumably collagenous bands, while the earlier extracts consisted of blue-staining, presumably noncollagenous bands. No significant differences were found between the glomerular and tubular basement membrane extracts.

Animals↗
PubMed1979

Isolation and characterization of human placental chorionic villar extracellular matrix.

The cell-free extracellular matrix of human placental chorionic villi has been prepared by a procedure employing extraction of the terminal villar fragments with the detergents Triton X-100 and sodium deoxycholate. The isolated human placental extracellular matrix retains an intact, but collapsed, histoarchitecture, as observed by scanning and transmission electron microscopy. It remains intact, in large part because of the presence of continuous sheets of villar basement membranes and associated interstitial collagen fibers and scattered patches of fibrin. The staining charcteristics and chemical composition of the isolated human placental extracellular matrlix are similar to those reported for basement membranes in several tissues and indicate the presence of collagen-like and glycoprotein components in this preparation. Gel electrophoresis of urea-SDS-mercaptoethanol extracts of the matrix showed that it consists of several polypeptide components of various molecuar weights, some of which are associated into high molecular weight complexes by disulfide bonds.

Amino Acids↗
PubMed1979

pH gradient elution of human IgG1, IgG2 and IgG4 from protein A-sepharose.

Pooled human serum having a normal IgG subclass content was chromatographed on a column of protein A-Sepharose. The immunoglobulins that bound to the column at pH 7.0 were eluted with a pH gradient generated by 3 equal volumes of citrate/phosphate buffer at pH 5.0, 4.5 and 2.2. The elution pattern consisted of two major overlapping peaks centered 0.4 pH units apart in the pH gradient; on average the first peak centered at pH 4.7, and the second centered at pH 4.3. Upon second passage of each component, single major peaks centered at the appropriate pH were seen. The subclass distributions of the re-chromatographed peaks were as follows: the high pH-eluting IgG contained less than 1% IgG1, 95% IgG2 and 5% IgG4; the low pH-eluting IgG contained 90% IgG1, 6% Ig2 and 5% IgG4. IgG3 does not bind to protein A and was thus absent from the pH gradient fractions. Chromatography on protein A-Sepharose provides a means for separating normal human IgG1 from IgG2 and may therefore prove useful as an additional tool for studying the relative biological role of these IgG subclasses.

Animals↗
PubMed1979

Biosynthesis of basement membrane matrix by isolated rat renal glomeruli.

The incorporation of radioactive precursors into the extracellular basement membrane matrix has been investigated in a purified preparation of isolated rat kidney glomeruli. Using deoxycholate extraction of isolated glomeruli which were incubated with radioactively labeled amino acids and carbohydrates, as an assay system for the measurement of incorporation of basement membrane precursors into intact deoxycholate insoluble basement membrane material, we demonstrated the in vitro biosynthesis of this structure. The assay system minimized the possibility of contamination of the isolated labeled basement membrane with labeled cell membrane fragments which may occur with the standard isolation procedures involving sonication and centrifugation. A linear incorporation of labeled proline, lysine, glycine, glucosamine, and galactose into glomerular basement membrane was shown. Basement membrane synthesis was inhibited by metabolic poisons and protein synthesis inhibitors as well as by inhibitors of collagen synthesis, but not by colchicine, an inhibitor of collagen secretion. Rhe appearance of 14C-hydroxyproline in the basement membrane matrix was negligible during the first 4 hours of incubation and rose only to 1% of the total proline counts thereafter. The results are consistent with the characterization of glomerular basement membrane synthesis and deposition as a two component system comprising a rapidly synthesized and deposited noncollagenous glycoprotein component(s) and a collagenous component which is only deposited after a delay of 4 to 6 hours.

Aminopropionitrile↗
PubMed1979

Effect of paraquat treatment on prolyl hydroxylase activity and collagen synthesis of rat lung and kidney.

Morphological evidence has shown that the herbicide paraquat produces severe lung fibrosis in experimental animals. In order to investigate the biochemical basis for this fibrosis, prolyl hydroxylase activity, total hydroxyproline content and collagen and protein synthesis were estimated in rats (200 gm) which were pretreated with paraquat (25 mg/Kg; I.P.) nine days before sacrifice. Prolyl hydroxylase activity in the treated rats was significantly elevated in the lungs. However, no such increase was seen in the kidney. There was no significant change in the total hydroxyproline content or collagen formation in the treated animals. When paraquat was added to the culture medium and incubated with lung slices, there was a marked decrease in collagen synthesis along with a decrease in protein synthesis. When paraquat was added to lung cells in culture, it was found that lung explants were more sensitive to paraquat toxicity than cells obtained by trypsinization. In explants which were sensitive to paraquat, there was a marked decrease in both protein synthesis and collagen synthesis.

Animals↗
PubMed1979

Synthesis of [24, 25-3H]cholesterol: a new substrate for determining the rate of cholesterol side chain oxidation.

A procedure for the synthesis of [24,25-3H]cholesterol from the nonradioactive precursor desmosterol is described. The intermediate, isodesmosterol, which was purified by column chromatography, was formed to protect the original double bond (delta 5-6) from hydrogenation. Tritium was introduced into the side chain by catalytic reduction of the double bond (delta 24-25) of the isodesmosterol in the presence of carrier-free tritium. After ring rearrangement of the iso-[24,25-3H]cholesterol acetate, the acetate was hydrolyzed to form the free labeled cholesterol. Hepatic oxidation of the [24,25-3H]cholesterol side chain release tritium into water which freely equilibrates with cell and body water pools. Thus, the rate of 3H2O appearance corresponds to the rate of cholesterol side chain oxidation. Applications of this method to in vivo, isolated perfused liver, and isolated hepatocyte preparations of the rat are discussed.

Animals↗