Biomedical subjects

B Suchy

Publications and source records attributed to B Suchy.

4 recordsLinked to original sources

PubMed1992

K-ras point mutations in human colorectal carcinomas: relation to aneuploidy and metastasis.

Material from paraffin sections of 109 human colorectal carcinomas, mostly obtained at autopsy, was analyzed for the presence of K-ras point mutations at codon 12, position 2. Mutations at this position were found in 23 cases (21.1%). Aneuploid colorectal carcinomas showed a significantly higher prevalence of K-ras point mutations than diploid tumors, suggesting an involvement of ras mutations in the development of aneuploidy. No differences in the prevalence of K-ras mutations were observed with respect to the patients' age, sex and tumor type. In metastases, the type of ras gene mutation was always identical to that of the respective primary tumor. Mutations were not found in metastases from primary tumors devoid of ras mutations. This renders a clonal selection of K-ras mutated cells from a wild-type primary tumor during the metastatic process unlikely. However, nearly twice as many ras gene mutations were seen in metastatic than in non-metastatic primary tumors.

Aneuploidy↗

PubMed1991

Carcinogen-induced liver tumours of Wistar rats: absence of activated ras genes and of N-rasC.

We examined mutational activation of ras genes in rat liver preneoplasias and tumours induced by diethylnitrosamine and N-methyl-N-nitrosourea (NMU). In accordance with previous reports on H- and K-ras genes, no mutations were detected in the investigated hepatic tumours and prestages suggesting that neither mutations at codons 12, 13 and 61 of H- and N-ras nor a mutation in the last intron of the H-ras gene are involved in initiation and progression of rat hepatocellular carcinomas. In the course of this investigation we found two N-ras genes (N-rasA, N-rasB). Surprisingly N-rasC, which is present in the germ line of Fischer rats, is missing in Wistar rats. This suggests different numbers of germline N-ras genes in members of one species. Two out of eight NMU-induced liver tumours exhibited additional N-ras-related sequences of unknown origin.

Animals↗

PubMed1990

[PCR: DNA amplification from histological sections].

Specific DNA sequences can be amplified from tissue material by means of the polymerase chain reaction (PCR) using oligonucleotides homologous to upstream and downstream flanking regions as primers for repeated cycles of Taq polymerase-mediated DNA synthesis (primer extension) in vitro. The amplification product provides the unique possibility to analyze genomic alterations (mutations, deletions, translocations) which may play a role during pathogenetic processes, or to detect heterologous (viral, bacterial) nucleic acids with maximum sensitivity. PCR with morphologically defined material from histologic sections gives the chance to bridge the gap between morphological description of a disease and the underlying molecular alteration. PCR from sections can be performed even from paraffin-embedded material of archival specimens. As an example a ras gene mutation analysis of human colorectal cancers and their metastasis and of human seminomas is presented. Only minute amounts of biological material are required for PCR, as exemplified with material punched from defined preneoplastic areas in rat liver cryostat sections. Using this material, not only a thorough mutational analysis of DNA of preneoplastic foci is possible after a simultaneous PCR amplification of various genomic sequences, but also an investigation of transcription activity after reverse transcription of mRNA into cDNA, as shown for c-myc expression during preneoplasia. The extremely high sensitivity of the method requires severe precaution with respect to contamination, and product control by Southern blots or sequencing. PCR from histological sections will become a valuable tool for analyzing molecular mechanisms of disease based on the classical morphological parameters of pathology.

Animals↗

PubMed1979

[Clinical results with granulocyte transfusion (author's transl)].

16 adult patients with granulocytopenia and septicemia resistant to antibiotics received 42 granulocyte transfusions. The granulocytes were obtained from healthy donors with a blood cell separator by continuous flow centrifugation. Adding hydroxyethyl-starch an average of 1.8 X 10(10) leukocytes with 69% granulocytes were harvested in 3.5 hours. A small leukocyte increment after the transfusion was seen in half of the recipients. No correlation could be found between fever lysis and survival of the infection, which occurred in half of the cases too. A granulocyte transfusion is indicated in patients, who have granulocytopenia, sepsis and no evidence of bone marrow recovery.

Adult↗