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Biomedical subjects

P Weber

Publications and source records attributed to P Weber.

At least 307 records · Page 17Linked to original sources
PubMed1982

Intraprostatic and subcutaneous transplantation of a spontaneous prostatic carcinoma (11095) to male Fischer rats (F344): an ultrastructural study.

A prostate carcinoma arising spontaneously in a Fischer rat was transplanted by cell suspension to male and female Fischer rats. Tumour growth was rapid in both subcutaneous and intraprostatic sites of inoculation in males and subcutaneously in females. The growth rate was greater in male than in female hosts and the tumour developed as a solid form in both groups. It had a heterogeneous cell population with ultrastructural characteristics similar to basal cells of the normal prostate and to tumour cells seen in human prostate adenocarcinoma. Later stages of tumour growth transformed it to a cornifying squamous cell carcinoma. The morphological description of tumours produced by transplantation provides the basis for further studies using this method as a model for investigating the response of prostate carcinoma to endocrine manipulation.

Adenocarcinoma↗
PubMed1981

Cleavage of dehydroalanine-containing peptides with mercuric acetate.

The dehydroalanine containing peptides glycyldehydroalanine and t-butyloxy-carbonyl-L-alanyldehydroalanyl-beta-methyl-D, L-aspartic acid methyl ester were synthesized, respectively, from chloroacetamide and pyruvate and from t-butyloxycarbonyl-L-alanyl-S-methyl-L-cysteinyl-beta-methyl-D, L-aspartic acid methyl ester. They were reacted with mercuric acetate in water, 50% methanol and dimethylformamide at 25 degrees and at 80 degrees for various time periods. Reaction proceeded to yield an amino acid amide from the N-terminal side of the unsaturated residue and pyruvate from the C-terminal side. Yields of amino acid amides were 76% for the dipeptide and 40% for the tripeptide. The applicability of the neutral reaction conditions employed to the cleavage of glycoproteins containing both O- and N-glycosidically-linked carbohydrate chains following beta-elimination of the serine and threonine linked oligosaccharides is pointed out.

Chemical Phenomena↗
PubMed1981

The effect of leucine on plasma insulin following endotoxin shock in the rat.

We have previously documented the ability of exogenous L-leucine to accelerate the endotoxin shock syndrome. In this report we have tested the hypothesis that the mechanism for this action of leucine was via an induction of pancreatic insulin hypersecretion. Pentobarbital-anesthetized rats were injected with 1 mg/100 gm S. enteritidis endotoxin (LD90) or vehicle and infused with either Krebs Henseleit vehicle or 0.153 M leucine to a dose of 7.6 mmole/kg. Following leucine administration, plasma concentrations of leucine decayed at an exponential rate in both endotoxin-treated and sham-treated groups. The extrapolated initial leucine concentration in the endotoxin-treated rats was significantly higher than the sham rats, indicating a lower circulating blood volume in the endotoxin-treated group. In the vehicle and endotoxin-treated group, insulin levels exhibited a biphasic response, significantly lower at 30 minutes and significantly higher at three hours. In the leucine- and endotoxin-treated groups, insulin levels were markedly higher 0.5, 2, and 3 hours after leucine infusion. In the two non-endotoxin treated groups, no significant changes in insulin levels were noted after infusion. Therefore, the shock accelerating action of leucine may be due to a direct stimulation of insulin secretion inducing a prolonged hyperinsulinemia.

Animals↗
PubMed1979

Studies on the specificity of immunohistochemical techniques for cyclic AMP and cyclic GMP.

UNLABELLED: Immunohistochemical studies employing antibodies against cyclic nucleotides indicate that cyclic AMP and cyclic GMP are localized to distinct subcellular sites. These antibodies, however, cross-react weakly with noncyclic nucleotides (eg. ATP, GTP), and therefore we investigated the speficity of the immunohistochemical technique. Slides of fetal nuclei exposed to gaseous nitrous acid demonstrated reduced immunofluorescence. The slides were then incubated with cyclic and noncyclic nucleotides, and restoration of distinct cyclic AMP and cyclic GMP staining pattern was achieved only with appropriate cyclic nucleotides. Antibodies that were used have a greater affinity for acetylated derivatives of cyclic nucleotides. By using a gas phase technique, tissue slices were acetylated and immunohistochemical staining intensity was compared with the effect of acetylation on antibody affinity for various nucleotides. Acetylation greatly increased affinity of cyclic AMP antibody for cyclic AMP but not other nucleotides, and greatly intensified cyclic AMP staining. Acetylation moderately increased affinity of cyclic GMP antibody for cyclic GMP, and moderately intensified cyclic GMP staining. CONCLUSION: Both nitrous acid and acetylation studies support the specificity of the immunohistochemical method for cyclic nucleotides.

Acetylation↗
PubMed1979

[Acute and chronic experimental posttraumatic osteomyelitis in guinea pigs].

The model of an experimental posttraumatic osteomyelitis is described. Acute and chronic osteomyelitis was produced by inoculation of 10(5) Staph. aureus or E. coli to fractured femora--stabilised or not--with intramedullar nailing. The results are discussed. The model seems to be useful to further studies on posttraumatic osteomyelitis.

Acute Disease↗
PubMed1978

Biochemical and immunological characterization of human opsonic alpha2SB glycoprotein: its identity with cold-insoluble globulin.

The relationship between human cold-insoluble globulin (CIg, plasma fibronectin) and the human serum opsonic alpha2SB glycoprotein was investigated using immunochemical and biochemical techniques. The two proteins appeared to have identical molecular weights by sodium dodecyl sulfate-polyacrylamide gel electrophoresis on 3.3% gels; have identical migration in the native state on 2.7 to 27% gradient polyacrylamide gels; and have a similar amino acid composition within the accuracy of analysis. Human serum demonstrates antigenic identity when diffused against monospecific antisera to both proteins confirming the presence of common antigenic sites on both molecules. Purified human serum opsonic alpha2SB glycoprotein and purified CIg also demonstrate antigenic identity when diffused against monospecific antiserum to either of the isolated proteins. Antiserum to both proteins also inhibits in vitro hepatic Kupffer cell phagocytic uptake of test particles. These results suggest the idenity of these two proteins and reveal a major physiological function for human plasma CIg. Thus, CIg may be important in the regulation of hepatic reticuloendothelial phagocytic activity and nonspecific systemic host defense. This process of systemic host defense has been shown to be depressed in patients following trauma, major surgery, burn injury, and during neoplastic disease, and, in part, mediated by a deficiency or depletion of the alpha2SB glycoprotein.

Amino Acids↗
PubMed1978

A histochemical study of glycosidases in benign prostatic hyperplasia and in prostatic carcinoma in the human.

In benign hyperplasia marked beta-glucuronidase and N-acetyl-beta-glucosaminidase activity was seen in the prostatic epithelium whereas the reactions for 5 other glycosidases were only slight or negative. The intensity of the reaction for the glycosidases in prostatic carcinoma was dependent upon the degree of the differentiation. The possible importance of glycosidases for the invasiveness of prostatic carcinoma is briefly discussed.

Adenocarcinoma↗