Biomedical subjects

A Kriegel

Publications and source records attributed to A Kriegel.

11 recordsLinked to original sources

PubMed1997

Transforming growth factor-beta 1 increases lysyl oxidase enzyme activity and mRNA in rat aortic smooth muscle cells.

PURPOSE: This investigation was designed to test the hypothesis that transforming growth factor-beta 1 (TGF-beta 1) regulates lysyl oxidase secretion from vascular smooth muscle cells. Lysyl oxidase is an enzyme that catalyzes an essential step in collagen and elastin cross-linking in the extracellular matrix, and TGF-beta 1 has been implicated in the pathogenesis of restenosis after vascular injury. The effect of TGF-beta 1 on lysyl oxidase in vascular smooth muscle cells has not been previously defined. METHODS: Rat aortic smooth muscle cells were grown in culture to confluence. Cells in passage 2 to 6 were incubated for 24 hours in media containing 0.1, 0.5, 1.0, or 10.0 ng/ml of TGF-beta 1. Lysyl oxidase activity in the media was quantitated with a tritium-release bioassay against an insoluble 3H-labeled aortic clastin substrate. Northern blot analyses were performed to determine steady-state levels of lysyl oxidase mRNA in the smooth muscle cells. RESULTS: Lysyl oxidase activity in the media increased 1.5-fold above control levels after exposure to 10 ng/ml of TGF-beta 1 (p < 0.01). This increase in lysyl oxidase activity was associated with a concentration-dependent increase in steady-state levels of lysyl oxidase mRNA, being 4.3- and 6.2-fold above control levels after exposure to 1 and 10 ng/ml TGF-beta 1, respectively (p < 0.01). The observed increase in steady-state lysyl oxidase mRNA after exposure to TGF-beta 1 was also time-dependent over the 24-hour experimental period. CONCLUSIONS: TGF-beta 1 appears to regulate lysyl oxidase in cultured rat aortic smooth muscle cells. Increases in lysyl oxidase activity may be one of the mechanisms by which TGF-beta 1 contributes to arterial restenosis after vascular injury.

Animals↗

PubMed1994

[Blood serum and milk serum levels of sodium benzylpenicillin after intravenous regional antibiosis in surgery of the claw area in cattle].

An intravenous regional antibiosis using 10 Mega I.U. Sodium-Benzylpenicillin was carried out during surgery in 14 dairy cows affected with spontaneous occurring digital diseases. Blood serum and milk serum levels were determined over a period of 48 hours by means of a micro agar diffusion method using Sarcina lutea Stamm BGA Berlin as a test germ. Even before opening of the rubber tourniquet, penicillin traces were detectable in the blood serum of 6 cows. Maximal concentrations ranging from 0.43 mcg/ml to 8.63 mcg/ml were determined after 45 minutes to 4 hours. 24 hours after intravenous regional antibiosis no levels above the limit of detectability were determined. Significant lower maximal concentrations were found in claw amputation cases as compared with claw preserving surgical interventions. Milk serum levels showed delayed and lower maximal concentrations, ranging between 2.09 and 0.09 mcg/ml. In 5 animals no positive levels were detected. After 48 hours, penicillin levels were below the limit of detectability in the milk of all examined animals.

Anesthesia, Conduction↗

PubMed1991

Assessment of proliferative activity in carcinomas of the human alimentary tract by Ki-67 immunostaining.

The monoclonal antibody (MAb) Ki-67, which is directed against a proliferation-associated nuclear antigen, was used to measure tumor proliferation in 165 carcinomas of the esophagus, stomach, colon and rectum with an indirect immunoperoxidase technique. The percentage of Ki-67-positive tumor cells (Ki-67 index) was evaluated with the point-counting method. The Ki-67 index in gastric cancers (mean, 24.8%; standard deviation, 11.1%) was significantly lower than in tumors of the esophagus (35.7 +/- 12.6%), colon (37.6 +/- 15.2%), and rectum (34.3 +/- 16.4%). A wide range of the Ki-67 index (5.9-75.3%) could be observed within the various tumor types. In recurrent colorectal carcinomas, the Ki-67 index significantly increased to 51.9%. The Ki-67 index was independent of pathologic (e.g., TNM-stage, grading, tumor volume, tumor site) and clinical variables (age and gender of the patients). A marked heterogeneity of Ki-67 expression within different tumor stages was noted. Statistically significant regional variations in tumor proliferation existed between different areas within the same tumor.

Adult↗

PubMed1989

Critical evaluation of histochemical and immunochemical methods for the demonstration of vascular supply in rectal and oesophageal cancer.

The vascularisation of rectal and oesophageal carcinomas and of normal mucosa was studied using histochemical and immunohistochemical methods. Endothelial cells were stained for alkaline phosphatase (AP) using an azo-dye procedure. Histochemical results were compared with the immunohistochemical identification of endothelial cells using the monoclonal antibody BW 200 recognising an epitope restricted to human endothelial cells. In the AP experiments the simultaneous reactivity of stromal tissue often precluded the exact evaluation of tumour blood vessels. Immunohistochemistry facilitated the identification of vessels in neoplastic tissues and allowed a quantitative analysis of vascular volume by means of point-counting. Vascular volumes of normal tissues exceeded those of tumours by a factor of 1.6. This immunohistochemical technique has potential application in studying the importance of tumour blood supply in man, especially in relation to radiotherapy.

Antibodies, Monoclonal↗

PubMed1978