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G Meyer

Publications and source records attributed to G Meyer.

589 records · Page 33Linked to original sources
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[Cancers, oncogenesis and oncogenes].

The carcinogenic transformation depends on the presence of particular genes, the oncogenes, which are, as a matter of fact, normal cellular genes. The oncogenic retro-viruses are mosaic genomes, transducing oncogenes in the infected cells. These genes are expressed: the product has an activity of protein kinase. The expression is increased in the transformed cells, because the oncogenes are either linked to strong viral promoters in the oncogenic viruses, or translocated in the vicinity of immunoglobulin genes in the case of Burkitt lymphoma. Moreover, there is some modifications (punctual mutations or deletions) of the primary sequence of the protein.

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[Relationship between tumor antigens and histocompatibility antigens at the cell membrane].

The authors outline schematically the major histocompatibility complex as well as the relationship between tumor neo-antigen and pre-existing antigens at the cell surface. They note that these two antigenic systems are not independent and in particular, the major histocompatibility system (H-2) co-segregates with the tumour antigens. Considering the complexity of the H=2 system (a H-2 allele does not correspond to any single transplantation antigen but to a combination of several antigens units simultaneously present), the authors recall Boyse's hypothesis, revised by Haywood and Mc Khann, which propose that tumour antigens are a rearrangement of H-2 substructures. Moreover, it is possible that the relationship between H-2 and resistance to cancer may be attributed directly to the action of genes controlling the immune response (Ir region) which could also intervene in recognition of these tumour antigens. Finally, recent results obtained seem to show that some tumour antigens cross-react with H-2 fractions. This fact prevents the mice bearing these types of alleles from being immunized against the cross-reacting tumours. If this result could be transposed to the human situation, it would explain the frequency of certain types of tumours in defined H-LA groups and could allow the prediction of high-risk groups.

Animals↗
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Biliary mucin secreted by cultured human gallbladder epithelial cells carries the epitope of CA 19-9.

Serum CA 19-9 is increased in patients with different gastrointestinal malignancies. Unfortunately, CA 19-9 is also detected in high concentrations in normal bile causing unspecific serum elevations during inflammatory disease of the biliary tract and cholestasis. In order to identify the source of CA 19-9 in bile, the capacity of cultured human gallbladder epithelial cells (HGBEC) to secrete CA 19-9 was investigated. Cells were harvested from gallbladders removed by cholecystectomy and cultured for up to 14 days in collagen I coated 24-well culture dishes. CA 19-9 was measured in the culture medium by a solid-phase CA 19-9 EIA (Boehringer). In addition, culture medium was separated by Sepharose 4B-Cl, Concanavalin-A (Con-A) and CA 19-9 affinity chromatography. Significant CA 19-9 activity was measured in the culture medium after a 24 hour incubation period. Following separation of the culture medium by Sepharose 4B-Cl and Con-A affinity chromatography, 90% of the CA 19-9 activity was recovered in the exclusion volume (> 2000 kDa) from which 90% were identified as Con-A negative. A close correlation was found between CA 19-9 and concentrations of mucin purified from human gallbladder bile. Furthermore, CA 19-9 affinity chromatography selectively extracted mucins from the culture medium of HGBEC. Finally, addition of the mucin secretagogue bethanechol (6 mM) to the culture medium increased CA 19-9 activity in the medium. In conclusion, normal HGBEC secrete mucins carrying the epitope of CA 19-9. During inflammatory biliary disease unspecific elevation of CA 19-9 in serum may reflect both inflammatory hypersecretion and leakage of biliary mucins into serum.

Bethanechol↗
PubMedDate not supplied

Laparoscopic liver resection compared with conventional partial hepatectomy--a prospective analysis.

BACKGROUND/AIMS: Tumor size and location are the major influences on the practicality of a laparoscopic operation. Visual control of the operating field is important for isolation and ligation of blood vessels and bile ducts after selective liver dissection by suitable techniques such as the water-jet dissector. METHODOLOGY: We carried out laparoscopic liver resections with the Jet-Cutter in 17 patients. The results were compared to a control group of 17 closely matched patients undergoing conventional hepatic resection during the period of the study. In 1 patient, conversion of laparoscopic to an open operation was required. RESULTS: Early in our learning curve, the duration of operation and time for resection were significantly longer in the laparoscopic group. Following laparoscopic operation, patients were discharged from the hospital after a mean of 7.8+/-8.2 days; patients having undergone conventional operation were discharged after a mean of 11.6+/-12.8 days. CONCLUSIONS: Laparoscopic liver resection is technically feasible, but, at present, careful patient selection is required.

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