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Biomedical subjects

A Gregoire

Publications and source records attributed to A Gregoire.

35 records · Page 2Linked to original sources
PubMed1986

Identification of two pro-VIP forms in a human neuroblastoma cell line.

The immunoreactivity of VIP and PHI standards, immobilized on a nitrocellulose membrane, was first assayed with various detection procedures. For VIP, the double bridge peroxidase-antiperoxidase (PAP) method was the most sensitive procedure, giving a detection limit of 0.1-0.3 pmol per mm2 with the 4 rabbit anti-VIP antisera tested. By contrast, the detection limit of immobilized PHI was 100 times higher with the 4 rabbit anti-PHI/PHM antisera tested presumably because major antigenic sites were masked in the immobilized peptide. With this information at hand, the VIP and PHI immunoreactivity of human neuroblastoma NB-OK-1 cells was tested after extraction, SDS-PAGE, electrotransfer, and PAP immunodetection. Two faint immunoreactive bands corresponding to two pro-VIP forms with an Mr of, respectively, 19 kDa and 18 kDa, were detected in undifferentiated cells. These distinct bands increased progressively and markedly during differentiation in the presence of dibutyryl cyclic AMP. In addition, two intermediary VIP forms of lower Mr (11 kDa and 6 kDa) and 3 kDa VIP itself were also present after 2 days of differentiation. The 19 kDa and 18 kDa pro-VIP forms were detected with a sensitivity several times higher than that of VIP and their staining was specific for VIP epitopes. By contrast, when using 4 rabbit anti-PHI/PHM antisera, we observed essentially the strong unspecific staining of a 17 kDa polypeptide. VIP immunoreactivity was also visualized by immunocytochemistry in neuroblastoma cells cultured on glass coverslips and fixed in situ. Specific VIP staining using the PAP method was present in 10 percent of the cells in the undifferentiated state.(ABSTRACT TRUNCATED AT 250 WORDS)

Bucladesine↗
PubMed1983

Purification of highly radioactive mouse interferon produced by Ehrlich ascites tumour cells induced by Sendai virus.

Mouse interferon (IFN) was produced to high titres after induction of Ehrlich ascites tumour cells with Sendai virus by using an improved procedure. The IFN molecules were labelled during their synthesis by the incorporation of [3H]leucine and [3H]lysine. Electrophoretically homogeneous labelled IFN with a molecular weight of 34000 was obtained after a two-step purification procedure using poly(I)-agarose and octyl-Sepharose column chromatography followed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The specific radioactivity of this IFN was about 10 ct/min/IFN unit.

Animals↗
PubMed1983

Interferon effect on cytolytic T lymphocytes in a single cycle assay.

In this study we analyse cell-mediated cytotoxicity by the use of 51chromium release and the killer cell enumeration assay. The latter enabled us to estimate cell-mediated cytotoxicity in a single cycle, which confirms the protective effect of interferon (IFN) after target cell treatment. This anti-cytolytic resistance is detected best by microassociation when effector and target cells are separately treated with IFN and associated thereafter. We suggest that, in inflammatory areas, enhanced cytotoxic activity of the IFN-treated effector cells is only operative before the establishment of protection in the targets, which is somewhat slower and appears in about 18 hr. Resistance of the targets could be at least partly attributed to the incapacity of effector cells to bind to them.

Animals↗
PubMed1982

Observer variation in the interpretation of xeromammograms.

We have examined variation in the interpretation of xeromammograms among radiologists designated to take part in a Canadian multicenter randomized controlled trial of screening for breast cancer. Radiologists read 100 xeromammograms comprising 10 histologically proved cancers, 40 benign abnormalities, and 50 normal films. Radiologists' opinions differed widely on the frequency of suspected or identified cancer. The diagnostic category "suspicion of cancer" or "cancer" was selected by radiologists for 10-55% of the films, and biopsy or aspiration was recommended for 21 to 53% of patients whose films were examined. Agreement on specific diagnostic categories was greatest for the diagnosis of cancer; agreement was least for the diagnosis of benign abnormalities and intermediate for the diagnosis of normality. Known cancers were in general correctly identified. These results indicate a need for development of methods to reduce observer variation in a interpretation of xeromammograms while preserving diagnostic sensitivity and validity. Results also emphasize the importance of developing strategies to ensure quality control in multicenter trials.

Breast Neoplasms↗
PubMed1980

Induction of delta 3(4) ketosteroid synthesis by interferon in mouse adrenal tumour cell cultures.

Interferon, like cholera toxin, induces in mouse adrenal YI cells the production of delta 3(4) ketosteroids. In parallel, cyclic AMP (cAMP) is activated. At high concentrations, mouse but not human interferon induces a cell rounding effect, similar to that obtained with cholera toxin. In YI cells transformed by simian adenovirus 7, production of cAMP is still increased by that of steroids is blocked. The role if interferon in these cellular events is discussed.

Adenoviridae↗
PubMed1977

[Caustic lesions of the esophagus in the child].

On the basis of a study involving 21 children treated over a 10 year period, the authors describe a method for the management of a child following the ingestion of a caustic fluid: emergency oesophagoscopy to determine the extent and nature on the lesions, in severe forms, alimentation gastrostomy, which would seem to be preferable to parenteral alimentation, is carried out, on the 21st day, a new endoscopic and radiological assessment, permitting distinction between those cases which are cured and those progressing to stenosis. In this latter group, the choice is made between dilatations and oesophagoplasty on the basis on the lesions present and the development of complications during dilatation.

Caustics↗
PubMedDate not supplied

Lumbo-sacral agenesis. Clinical analysis and treatment relating to 4 observations.

Lumbo-sacral agenesis fall within the framework of numerical anomalies by default of the vertebral column. They are characterized by a more or less significant absence of vertebrae of the sacral, lumbar and, less frequently, thoracic regions. They are grouped in Foix and Hilleman's "crural-vesical-gluteal dystrophy syndrome". It was Ranshaw and Stanley who first proposed a classification of sacral and lumbo-sacral agenesis into 3 groups. Being difficult to refer strictly to such a classification, the Authors divide their series of 56 cases of sacral agenesis into 3 groups, putting total sacral agenesis with different degrees of lumbar and thoracic agenesis into the first group and describing the treatment of 4 cases included in this group. The follow-up of the mentioned cases leads to the following considerations: 1. From the embryonal point of view, this pathology comes within the "caudal regression syndrome". Such regression, as first referred by Duhamel, results excessive in these cases. 2. Maternal diabetes seems to be the dominant etiology. 3. Accurate clinical and X Ray examination must be carried out before establishing the therapeutic iter, as prognosis depends on the instability of the rachis, the mobility of the hips as well as on the flexibility of the knees. 4. In view of improving functional possibilities and giving the patient maximum autonomy, both in sitting and standing positions, two types of interventions are envisaged: fixation of the spine correction of the lower limbs.

Abnormalities, Multiple↗
PubMedDate not supplied

Immunomodulatory effects of arginine butyrate.

We have studied the effect of arginine butyrate on T cell and macrophage functions. When target cells are treated with this substance, they become resistant to T cell-mediated cytotoxicity, as detected by the chromium assay. In contrast, when effector T cells are treated, the cytotoxicity seems to be augmented. Peritoneal macrophages incubated with butyrate are increasingly adhesive to substrate. After in vivo treatment, spleen derived macrophages show an augmented cytostatic capacity in the presence of L1210 cells and an enhanced phagocytic activity for IgG-coated erythrocytes. To sum up, the overall effects of butyrate salts on different immune functions are somewhat reminiscent of that of interferon. It is likely that these immune effects contribute, at least in part, to explain its antitumor properties observed in grafted tumors in mice.

Adjuvants, Immunologic↗