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Biomedical subjects

H Fleury

Publications and source records attributed to H Fleury.

64 records · Page 4Linked to original sources
PubMed1979

Membrane effects of thyrotropin-releasing hormone and estrogen shown by intracellular recording from pituitary cells.

The effects of thyrotropin-releasing hormone and 17 beta-estradiol on the electrical membrane properties of a prolactin-secretin pituitary cell line (GH3/B6) were studied with intracellular microelectrode recordings. Of the cells tested, 50 percent were excitable and displayed calcium-dependent action potentials when depolarized. When injected directly on the membrane of an excitable cell, thyrotropin-releasing hormone and 17 beta-estradiol induced action potentials within 1 minute. The spiking activity was preceded by a progressive increase of the input resistance without any detectable change in the resting membrane polarization. The results reveal a rapid effect of both substances on the membrane of GH3/B6 cells. In the case of thyrotropin-releasing hormone, which has both a short-term effect on release of prolactin and a long-term effect on its synthesis, the induced electrical activity may be associated with the stimulation of prolactin production. The physiological implication of 17 beta-estradiol-induced, calcium-dependent spiking activity remains to be elucidated.

Action Potentials↗
PubMed1977

An in vitro study of the susceptibility of cells from a meningioma of human origin for measles virus.

A cell culture from a meningioma of human origin was found permissive for the Edmonston strain of measles virus. Virus was isolated from the supernatant of infected cell sheet as soon as 48 hr post-inoculation. Cytopathic effect, observed by light microscopy, exhibited syncitia plus intracytoplasmic and intranuclear inclusions. Electron microscopy enabled viral nucleocapsids to be observed first in the cytoplasm and secondly within the nucleus of infected cells.

Brain Neoplasms↗
PubMed1975

[Lymphoblast transformation test in osteoarticular tuberculosis].

Bacteriological proof of an osteoarticular tuberculous lesion is difficult to obtain, notably in Pott's disease. The authors, on the basis of earlier work in the field of pulmonary pathology, wished to assess the value of the lymphocyte transformation test in the diagnosis of this disease. Old tuberculin from the Pasteur Institute and LP48 tuberoulin were used at different concentrations. Out of 10 tuberculous patients (8 with Pott's disease and 2 with white tumours), 9 had positive tests, of which 7 were strongly positive ; the average transformation value was 13 percent. This positiveness was a function of the condition of the patient, of the extent of the lesions, and of the treatment. Of the 25 control patients affected by an infectious, nonmicrobial or other osteoarticular process, 17 gave negative results in the test, and 8 were positive, two of whom had high values. The average transformation value was 4 percent. From this study it seems that a negative result in the LTT is a valuable argument against the diagnosis of osteoarticular tuberculois ; a weak positive result indicates tuberculin hypersensitivity without absolutely defining evolution of tuberculois ; a strongly positive test may be encountered in hyperergic states connected with prolonged infectious conditions in bones or joints.

Bone Diseases↗
PubMedDate not supplied

Dopamine inhibition of action potentials in a prolactin secreting cell line is modulated by oestrogen.

Secretory activity of the anterior pituitary gland is regulated by the brain through stimulatory and inhibitory substances released from nerve endings in the median eminence of the hypothalamus and carried by the adenohypophysial portal blood system to their respective target cells. These hypothalamic influences are modulated by the feedback action of peripheral hormones. Prolactin (PRL) secreting cells are, at least partially, under the stimulatory influence of thyrotropin releasing hromone (TRH) and of oestrogens. However, they are mainly controlled by inhibitory substances among which dopamine (DA) is one of the most potent in vivo as well as in vitro. The inhibitory effect of DA is reversed by oestrogen in vitro. The mechanism by which these factors interact on their target cells is poorly understood. The recent discovery that anterior pituitary cells are excitable and that they are able to generate Ca2+-dependent action potentials has led to the suggestion that these effects are involved in a stimulus-secretion coupling at the membrane level. In this paper, we report that DA inhibits both the spontaneous and TRH-induced action potentials in clonal PRL pituitary cells. In addition, oestradiol-17 beta is able to reverse the inhibitory effect of DA.

Action Potentials↗
PubMedDate not supplied

Replication of measles virus in a cell culture from a glioblastoma of human origin.

A cell culture from a glioblastoma of human origin infected with the Edmonston strain of measles virus produced and released infectious measles virus. All cellular types seemed to be involved in the process of virus replication. Staining with hematin-eosin revealed the presence of eosinophilic intracytoplasmic and intranuclear inclusions. Examination with the electron microscope revealed viral nucleocapsids in the cytoplasm and, rarely, in the nuclei of infected cells.

Brain Neoplasms↗
PubMedDate not supplied

Progression to AIDS or death as endpoints in HIV clinical trials.

PURPOSE: To assess progression to AIDS or death from month 4 after a protease inhibitor-containing regimen is initiated in a cohort of 1,281 patients. METHOD: We used Kaplan-Meier estimates of probability of clinical progression. RESULT: At month 4, most patients had an HIV-1 RNA plasma value below 500 copies/mL (78%) and a CD4 cell count above 300 cells/mm(3) (62%). Starting from month 4, clinical progression at 1 and 2 years of follow-up was low (<3% at 1 year) in patients with HIV RNA <500 copies/mL or 500-10,000 copies/mL and in patients with CD4 between 50 and 300 cells/mm(3) or >300 cells/mm(3). A higher risk of clinical progression (> or =10% at 1 year) was evidenced only in patients with poor response to antiretroviral therapy, that is, with CD4 <50 cells/mm(3) or CD4 between 50-300 cells/mm(3) together with an HIV RNA >10,000 copies/mL. CONCLUSION: In patients currently on antiretroviral therapy, clinical trials with clinical progression as endpoint are almost not feasible, except in patients with a poor immunovirological response to first- or second-line HAART.

Anti-HIV Agents↗
PubMedDate not supplied

[Long-term infection of a cell culture from newborn mouse brain with the FNV strain of yellow fever virus (author's transl)].

A cell culture from brains of one day old mice was infected with a high multiplicity of the French neurotropic strain of yellow fever virus (FNV); the infected cell culture produced and released infectious FNV for more than 180 days post-inoculation with titres between 10(0.6) and 10(6.4) PFU/ml. The cell sheet exhibited some rare plaques of round cells with a slow centrifugal extension; the destruction of the cell sheet was not complete before 200 days post-inoculation.

Animals↗
PubMedDate not supplied

Some ultrastructural aspects of the replication of a Yucaipa-like virus in Vero cells.

The replication in Vero cells of a Yucaipa-like virus isolated from a wild bird in West Africa (PLOC/Senegal/9/76) was studied with an electron microscope at days 6 and 8 post-inoculation. Viral nucleocapsids, 15 nm in diameter, were found in the cytoplasm, mainly beneath the cell membrane. Viral particles, 125 to 175 nm in diameter, were released from the cells by a budding process. No viral nucleocapsid could be observed within the nucleus of infected cells.

Animals↗