Biomedical subjects

W K Roth

Publications and source records attributed to W K Roth.

77 records · Page 5Linked to original sources

PubMed1989

Depletion of PDGF from serum inhibits growth of AIDS-related and sporadic Kaposi's sarcoma cells in culture.

We have examined the mitogenic potential of platelet-derived growth factor (PDGF) on AIDS (acquired immune deficiency syndrome)-related and sporadic Kaposi's sarcoma cells in comparison to fibroblasts at physiological and subphysiological calcium concentrations of the culture medium. At low calcium concentrations in the presence of 3% human serum the growth rate of fibroblasts and Kaposi's sarcoma (KS) cells is similarly reduced to less than half of the growth rate at physiological Ca2+ concentrations. In the presence of 3% PDGF depleted, platelet poor plasma-derived serum (PPPS) growth of KS cells ceased completely, whereas fibroblasts made 1-2 cell divisions within 15 days. At physiological Ca2+ concentrations, the reduced PDGF content in 3% PPPS had no effect on human embryonal fibroblasts and little effect on adult skin fibroblasts. In contrast, KS cells became growth-arrested after one to two doublings. This is consistent with the observation that PDGF B-chain mRNA could not be detected in our KS cells whereas PDGF receptor mRNA was expressed.

Acquired Immunodeficiency Syndrome↗

PubMed1988

Cultured, AIDS-related Kaposi's sarcoma cells express endothelial cell markers and are weakly malignant in vitro.

Up to 30% of patients with acquired immunodeficiency syndrome (AIDS) suffer from Kaposi's sarcoma (AIDS-KS). The histogenesis and neoplastic nature of this tumor is still controversial. We have established cell cultures of KS biopsies from 7 patients with AIDS. All donors were seropositive for the human immunodeficiency virus I (HIV-I), cytomegalovirus (CMV) and hepatitis B virus (HBV). The tumors were histologically shown to be KS. Cell cultures derived from these tumors all expressed the endothelial cell marker BMA 120 antigen. Most of these cultures were positive for acetylated low-density lipoprotein (acLDL) uptake and alkaline phosphatase (AP) expression, and negative for factor-VIII-related antigen (FVIII-RAg). The staining pattern was heterogeneous with respect to number of endothelial cell markers expressed in each culture. We conclude from subcloning experiments that the cultured cells cease to express acLDL receptor and AP, but not the antigen detected by the monoclonal antibody (MAb) BMA 120. The cells grew well in culture up to 50 passages and showed a fibroblast-like morphology. Assays performed to investigate their degree of malignancy revealed a significantly increased passage number under reduced serum conditions as compared to normal fibroblasts but no tumor formation in nude mice. Neither HIV, HBV nor CMV sequences were found in any of the cell lines tested. We conclude that AIDS-KS is an endothelial-cell-derived neoplasm of low malignancy and that HIV, HBV and CMV are not directly involved in its genesis.

Acquired Immunodeficiency Syndrome↗

PubMed1988

Sensitive non-radioactive dot-blot hybridization using DNA probes labelled with chelate group substituted psoralen and quantitative detection by europium ion fluorescence.

A new labelling method for cloned DNA probes used in hybridization assays is described. The DNA insert of recombinant plasmid DNA was made partially single-stranded for the labelling reaction by a restriction enzyme digest, followed by a controlled exonuclease III incubation. A thiol-containing psoralen derivative was covalently bound through irradiation with UV-light to the remaining double-stranded region of the plasmid DNA. The psoralen-SH groups were labelled with a large number of metal chelators (diethylentriamine pentaacetic acid, DTPA) using poly-L-lysine as a macromolecular carrier. The main advantage of the labelling procedure is that a high degree of labelling is achieved without modification of the single-stranded DNA hybridizing sequences. The specific hybrids were labelled after filter hybridization with europium ions through the chelating groups of DTPA. The europium ions were quantitatively detected by time-resolved fluorometry. The sensitivity of the assay for target DNA detection was in the low picogram range, comparable to radioactively labelled DNA probes.

Chelating Agents↗

PubMedDate not supplied

TGF beta and FGF-like growth factors involved in the pathogenesis of AIDS-associated Kaposi's sarcoma.

Conditioned media from cell cultures derived from AIDS-associated Kaposi's sarcoma (KS) promote the growth of KS cells, fibroblasts and endothelial cells. Application of KS cells to the chicken chorion allantoic membrane induces neo-angiogenesis similar to that caused by fibroblast growth factors (FGF). Testing for known factors of the FGF family by Northern blotting does not reveal any difference from control fibroblasts negative for such an activity in their supernatants. This indicates secretion of an unknown FGF-like factor by KS cells possessing autocrine (KS cells) and paracrine (fibroblasts, endothelial cells) activity. It was reported that transforming growth factor-beta (TGF beta) is secreted by HIV-infected lymphocytes in AIDS patients. By testing this growth factor on KS cell cultures, growth-promoting activity was observed 5 to 20 times greater than that of the control value without TGF beta.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

Anti-p53 autoantibodies in hepatitis C virus-infected patients.

Mutations in the p53 gene with generation of circulating autoantibodies to p53 protein (anti-p53) have been recently detected in a significant proportion of patients with different malignant diseases. Using ELISA methods we assessed alpha-fetoprotein (AFP) and anti-p53 as serological screening parameters for hepatocellular carcinoma (HCC) in 147 consecutive patients with hepatitis C virus-related chronic hepatitis. Liver cirrhosis was histologically diagnosed in 58 patients (39,5%) and a HCC confirmed in 7 patients (4.8%). Serum AFP levels were raised above 20 ng/ml in 26/147 patients (17.7%) and above 100 ng/ml in 5/147 patients (3.4%). In 6/7 patients with HCC serum AFP was raised above 20 ng/ml, but only in 3/7 cases above 100 ng/ml. Autoantibodies to p53 protein were detected in 3/7 patients with HCC, but in 0/140 patients without HCC (sensitivity 42.9%, specificity 100%). In conclusion, the presence of anti-p53 was specific for malignancy and independent of AFP status. Overall, the sensitivity of serological screening for HCC in patients with hepatitis C virus-related chronic hepatitis was improved by combining AFP measurements (level > 100 ng/ml) with the detection of anti-p53.

Adolescent↗