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Biomedical subjects

M Samson

Publications and source records attributed to M Samson.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Combination preoperative radiation and chemotherapy in adenocarcinoma of the rectum: preliminary report.

The plausibility of preoperative chemotherapy and radiotherapy in the treatment of patients with carcinoma of the rectum is demonstrated. The finding of specimens with no tumor along with a higher proportion of Dukes' A lesions than expected was most encouraging. Whether this is a false impression because of the small number of patients, or whether it demonstrates upgrading of pathologic staging by preoperative adjuvant therapy, remains to be determined.

Adenocarcinoma↗
PubMedDate not supplied

Monoclonal antibody GB36 raised against human trophoblast recognizes a novel epithelial antigen.

Monoclonal antibody GB36, which was raised against human term syncytiotrophoblastic microvilli, was found to recognize a novel epithelial antigen. The antibody immunoprecipitated several membrane proteins from BeWo (choriocarcinoma) and HT-29 (colon adenocarcinoma) cells. Under non-reducing conditions, four peptides of 180, 155, 135 and 130 kDa were revealed by SDS-PAGE analysis. Three peptides of slightly higher molecular weights were revealed under reducing conditions; these three peptides had identical pI (6.2) as shown by two-dimensional gel electrophoresis. By immunofluorescence, GB36 reacted with villous cytotrophoblasts and cytotrophoblasts of chorion laeve, as well as with the basal surface of syncytiotrophoblast and amniotic epithelium. Extravillous trophoblasts of cytotrophoblastic shell in the basal plate and the cytotrophoblastic cell island were non-reactive. It is suggested that the antigen of GB36 may play a role in the polarity of epithelial cells and the adhesion of epithelial cells to extracellular matrix.

Antibodies, Monoclonal↗
PubMedDate not supplied

Monoclonal antibodies (GB16, GB18, GB19, GB22) raised against human placental microvilli recognize the transferrin receptor.

GB16, GB18, GB19 and GB22 are mouse monoclonal antibodies produced against full-term human placental microvilli. These antibodies reacted predominantly with the apical surface of the syncytiotrophoblast from first-trimester and full-term placentae, and also reacted with several cell lines derived from non-haematopoietic tissues by immunofluorescence. The radioiodinated BeWo (choriocarcinoma) cell surface proteins were immunoprecipitated with these four antibodies and analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The results demonstrated that the immunoprecipitates migrated at 180 and 90 kilodaltons under non-reducing and reducing conditions, respectively. Using enzyme-linked immunosorbent assay, the antigens recognized by GB16, GB18, GB19, and GB22 were able to bind human transferrin. Immunoabsorption studies showed that these four antibodies bound to the same molecule as OKT9, an antibody to the transferrin receptor. Moreover, the reactivities of these antibodies with HL-60 (promyelocytic leukaemia) cells diminished following dimethyl sulphoxide-induced differentiation by flow cytometric analysis. These data indicate that these four antibodies recognize the transferrin receptor. By competition assay, GB18 bound to an epitope different from those recognized by GB16, GB19 and GB22. In addition, GB22 displayed significant growth inhibition against the activated lymphocytes and Daudi cells, but not against HL-60 or Jurkat cells. These data suggest that these four monoclonal anti-transferrin receptor antibodies will provide additional means to investigate the physiological roles played by the transferrin receptor.

Antibodies, Monoclonal↗
PubMedDate not supplied

Insulin regulation of protein phosphorylation in hepatocytes. Studies using two effectors: amiloride and natural aliphatic polyamines.

The effects of amiloride and of natural aliphatic polyamines on basal and hormone-stimulated protein phosphorylations in hepatocytes were studied. Cells isolated from adult rats were incubated in suspension with (32P)-orthophosphate, in the absence or presence of the effectors at varying concentrations and for different times; hepatocytes were then exposed to various hormones for 10 min. Phosphoproteins contained in total cell lysates were analyzed by one- and two-dimensional gel electrophoresis and autoradiography. Amiloride and spermine (the most effective amine) decreased the basal level of phosphorylation of proteins of 46, 34 and 22 kDal, and increased that of 18 kDal and 93 kDal proteins. These effects were maximal with external concentrations of 1 mM and 7.5-10 mM amiloride and spermine, respectively. They were detectable after a lag period of about 10 min and reached a plateau after 45 min. Pretreatment of cells with these effectors almost completely prevented stimulation of the phosphorylation of the 46 and 34 kDal proteins by insulin. In contrast, the effects of vasopressin on the same proteins were only partly inhibited, whereas those of glucagon appeared largely unaffected. The major effect observed in intact cells (i.e., decreased phosphorylation) could be reproduced in a cell-free system where no kinase activity persisted. Amiloride or spermine added directly to cell extracts strongly accelerated the dephosphorylation of 46 kDal protein and also of the 61 kDal protein identified as pyruvate kinase. Furthermore, restoration of the activity of this enzyme occurred concomitantly with dephosphorylation of the 61 kDal protein, an observation supporting the notion that amiloride and spermine could activate a phosphoprotein phosphatase.

Amiloride↗
PubMedDate not supplied

Primary thrombocythemia in a patient with cerebellar infarction.

A patient suffering from essential thrombocythemia presented manifestations of digital thromboses and two cerebral ischemic strokes. Anomalies of platelet function are discussed in relation to published data and the efficacy of antiaggregant treatment is stressed.

Adult↗
PubMedDate not supplied

The epidemiology and control of lymphatic filariasis on Lihir Island, New Ireland Province.

Clinical, parasitological and entomological surveys performed in 9 villages on Lihir Island, Papua New Guinea, before mass treatment with diethylcarbamazine (DEC), showed that lymphatic filariasis, caused by nocturnally periodic Wuchereria bancrofti, was endemic in 8 of them. Blood samples from 593 people revealed an overall microfilarial carrier rate of 24%. Amongst endemic villages, microfilarial carrier rates ranged from 5% to 43% and there was no significant difference in parasite prevalence between males and females. Obstructive filarial disease, defined as lymphoedema of the limbs or hydrocele, was observed in only 2% of 262 males examined. None of the 265 females examined had clinical symptoms. Entomological surveys yielded a total of 4095 mosquitoes including 3,692 anophelines and 241 culicines but only Anopheles farauti was found to harbour infective larvae of W. bancrofti. Pretreatment infection and infective rates of An. farauti were 7% and 1% respectively and up to 12 infective larvae were found in a single specimen. The microfilarial carrier rate in a cohort of people who received two DEC treatments dropped from 59% to 32% but the difference was not statistically significant. However, density of microfilaraemia decreased significantly from 170 to 10 mf/ml. Biannual mass treatment with DEC significantly reduced vector infection rates and transmission intensity on Lihir.

Diethylcarbamazine↗
PubMedDate not supplied

[Dysglobulinemic neuropathy. Apropos of IgD myeloma manifested by mononeuritis].

The authors report a case of IgD myeloma of which the initial symptom was a mononeuritis and the biological, immunological and ultrastructural study performed about this case. Then are reviewed the mechanisms, proved or hypothetical, by which are actually explained the event of neuropathies within lympho-plasmocytic disorders.

Amyloidosis↗