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Biomedical subjects

M Vincent

Publications and source records attributed to M Vincent.

At least 289 records · Page 16Linked to original sources

Computer analysis of cardiovascular activity in conscious unrestrained hypertensive rats of the Lyon strain.

A new computerized technique was developed for the continuous analysis of intra arterially recorded blood pressure (BP) curve in freely moving rats during long periods of time. For each cardiac cycle 5 parameters were calculated on-line and stored. Off-line processing allowed graphical display and statistical analysis. This technique demonstrated that 21 week-old genetically hypertensive rats from the Lyon strain (LH) exhibited higher and more variable BP and dp/dt max. with a lower heart rate than normotensive (LN) and low blood pressure (LL) controls. LL rats differed from LN by a slightly higher systolic and a lower diastolic BP.

Animals↗

[Effect of physical training by swimming on the arterial pressure, plasma and hypothalamo-post-hypophyseal vasopressin in genetically hypertensive rats of the Lyon strain].

The effect of a 5-week swimming training on systolic blood pressure (PAS) and vasopressin (AVP) and Neurophysins (NpT) concentration in the blood and content in the pituitary and the hypothalamus was studied in Lyon genetically hypertensive rats [LH] and in their controls: the normotensive [LN] and low blood pressure [LL] rats belonging to the 28th generation. Nine female rats of each group were trained 5 days a week for 5 weeks, starting with 2 h a day, with a 15 min increase every day, up to 6 h a day. The PAS was measured using an indirect plethysmographic technique one time a week during the whole training session. At the end of the training, the rats were decapitated. AVP and NpT were measured in blood, pituitary and hypothalamus, by radioimmunoassay (RIA). Hematocrit as well as plasma Na+, K+, protein and osmotic content were also measured. Results show that the training did not affect any of the studied parameters: mainly, there was no decrease in PAS or plasma AVP level in the hypertensive rats compared to the normotensive ones. The only difference was a lower AVP content in the pituitary of LH rats compared to LN (p less than 0.01), which is difficult to interpret. Our results shed doubt on the efficiency of a swimming training on the evolution of hypertension in the Lyon rat model.

Animals↗

Pulmonary sarcoidosis: flow cytometry measurement of lung T cell activation.

Lung T cell activation is considered a major factor in the pathogenesis of pulmonary sarcoidosis. Our study was designed to investigate several parameters of T cell activation among blood and alveolar cell populations, including expression of HLA-DR or MLR antigens, increased cell size, and presence of dividing cells. Blood sampling and bronchoalveolar lavages were performed in 20 patients with pulmonary sarcoidosis. Cell populations were analyzed by flow cytometry using immunofluorescence labeling with monoclonal antibodies to lymphocyte differentiation or activation antigens. Cell types were identified by their light-scattering properties. Cell cycle analysis was done after staining with acridine orange. Bronchoalveolar lavage contained a higher proportion of small T4-positive lymphocytes, and large cells of the same phenotype were detected in three patients. T cells bearing HLA-DR antigens were detected in six of 14 bronchoalveolar lavage samples. A marked increased of MLR-positive cells was found in the peripheral blood of eight of eight patients and in the bronchoalveolar lavage of five of seven patients. Increased percentages of cells in the S + G2 + M phases were found in blood lymphocytes from three patients and in half the bronchoalveolar lavage samples. Therefore, a variety of activation markers may be expressed by alveolar T cells. Their qualitative and quantitative assessment may provide additional criteria for staging the intensity of the alveolitis, and the possible relationship between these markers and disease progression or activity deserves long-term clinical investigation.

Adult↗

[Dietary calcium and arterial hypertension in the rat].

The effect of diets modified with respect to their calcium content was studied in three models of hypertensive rats: mineralocorticoid hypertension, DOCA + saline rats and genetic hypertension, SHR and LH rats. Normocalcemic control diet, was equilibrated in vitamins and contained 0.6 p. 100 Ca, 0.24 p. 100 Na and 0.6 p. 100 K. Low calcium diet with only 0.03 p. 100 Ca was studied in the SHR from 5 to 10 weeks of age. Calcium enriched diets contained 1.3, 1.2 and 2.5 p. 100 calcium respectively for DOCA (6 to 16 weeks), SHR (5 to 44 weeks) and LH (female rats, 4 to 22 weeks). In the SHR low calcium diet enhanced hypertension. At the opposite in the three models, calcium enriched diet lessened hypertension. The effect appeared within 2 weeks and was long lasting. These results clearly establish that in young hypertensive rat a low calcium diet enhances the development of hypertension and confirm earlier works with calcium enriched diets. Experimental and clinical data from other groups leads us to emphasize the importance of alimentary calcium in the hypertensive pathology.

Animals↗

[Chronic idiopathic eosinophilic pneumopathies. A study of 16 cases].

We report 16 cases of chronic idiopathic interstitial pneumonia (P.C.I.E.). P.C.I.E. has well defined clinical, radiological and biological characteristics which enable the eosinophilic pulmonary infiltrates to be recognised and the diagnosis to be confirmed without histological proof. The data from broncho-alveolar lavage (L.B.A.) show that besides the radiological infiltrates, there is a diffuse alveolar eosinophilia; sometimes confirming the pulmonary function results, which show a similar pattern to diffuse interstitial pneumonia (P.I.D.). The frequent association of asthma (50%) and extra-pulmonary signs (30%) may suggest a vasculitis or more particularly the Churg-Strauss syndrome, all the more so without a lung biopsy; however the evolution of the disease and the response to low dose steroid therapy is against the latter two being considered in the differential diagnosis. The prognosis for P.C.I.E. is good in the short and medium term; nevertheless during the period under observation (mean 6.3 years) steroid therapy could only be stopped in 3 out of 16 patients. The other patients were stable with a low dose of Cortisone. No patient with P.C.I.E. associated with asthma or hypergammaglobulinaemia or extra-pulmonary signs could be weaned from steroids. The authors advocate that the dose of steroids should be adjusted as low as possible to maintain an eosinophilia below 500/mm3.

Adult↗

[Comparative clinical trial of cefoperazone versus ampicillin + tobramycin in severe bronchopulmonary and pleural infectious pathology].

This study involved an open trial with parallel randomised series receiving either cefoperazone (2 g/d) or a combination of ampicillin (6 g/d) and tobramycin (3 to 4 mg/kg/d). The 30 patients included were of both sexes (male predominance), hospitalised, aged 62 +/- 11,5 years and suffering from a severe bronchopulmonary or pleural infection. Underlying pathology was serious (neoplasm, C.O.D.L., bronchiectasis, cardiac pathology). No significant difference was seen in the sampling of the two populations. Cefoperazone was prescribed in 2 infusions per 24 hours. Ampicillin was given as 3 infusions, followed by tobramycin administered by a similar number of injections. The duration of treatment was 16.8 +/- 9 days (cefoperazone) and 11,8 +/- 6,5 days (ampicillin + tobramycin). Overall evaluation (clinical, radiological and laboratory criteria) showed 88% (cefoperazone group) and 71% (ampicillin + tobramycin group) recovery and improvement rates. There were two failures in the cefoperazone group and 6 failures in the other group. These results were not statistically different. Three of the 6 failures could be attributed to resistance of the initial bacteria or selected by one or other type of treatment. None of the antibiotics prescribed raised any acceptability problems.

Aged↗

Cryptogenic fibrosing alveolitis and Epstein-Barr virus: an association?

13 patients with cryptogenic fibrosing alveolitis (CFA) and 12 with interstitial lung disease (ILD) of known cause were studied for their humoral response to herpes simplex virus (HSV), cytomegalovirus (CMV), and Epstein-Barr virus (EBV). Serum antibodies to HSV and CMV were within the normal range in all patients. 10 patients with CFA had raised serum antibodies to EBV, and IgA against viral-capsid antigen (VCA) was detectable in all 13. In the other 12 patients EBV serological profiles were normal and IgA against VCA was detectable in only 1 patient. The EBV antibody levels did not correlate with the level of circulating immune complexes, the presence of rheumatoid factors, or the cytological findings of the alveolitis. The presence of IgG against VCA in 5 CFA patients suggests local production of EBV-specific immunoglobulins. Elevated IgG and IgA against EBV in CFA may indicate non-specific depression of cell-mediated immunity or that EBV plays a part in the aetiology of CFA.

Adult↗

4-Methylumbelliferyl-glycosides as fluorescence probes of sugar-binding sites on lectin molecules: spectral properties and dependence of fluorescence on polarity and viscosity.

The spectral properties of 4-methylumbelliferyl-glycosides (MeUmb-glycosides) were investigated in order to assess their usefulness as probes of the microenvironment of sugar binding sites on lectin molecules. It was shown that the abnormally high values for fluorescence polarization of free MeUmb-glycosides (from 0.07 to 0.251) were due neither to their molecular size nor to the blockade of their movement, but to the short lifetimes (less than 0.55 ns) of the excited state of these compounds. Working essentially with two MeUmb-monosaccharides and one MeUmb-disaccharide (MeUmb-alpha-D-galactopyranoside, MeUmb-beta-D-galactopyranoside, and MeUmb-2-acetamido-2-deoxy-3-O-(beta-D-galactopyranosyl)-beta-D- galactopyranoside) which were solubilized in various solvents, it was demonstrated that solvent polarity and viscosity definitely affected the fluorescence intensity of MeUmb-glycosides. A low-polarity medium reduced this intensity, and high viscosity enhanced it. The implications of these findings are discussed in relation to the variations in the fluorescence intensity of MeUmb-glycosides when these compounds were bound to lectins.

Binding Sites↗

[Radiology of spontaneous pneumothorax in young patients. Apropos of 200 cases].

In 200 young patients with apparently idiopathic spontaneous pneumothorax, the following radiologic features were analyzed: degree of collapse on the initial chest film, areas of atelectasis, and presence of blebs, apical opacities, fibrous adhesions, pleural effusions, and controlateral shift of mediastinal structures. Confrontation of apical changes with pathologic findings in operative specimens suggests that mesothelial rupture with reactive hyperplasia results in a "pneumatization chamber" visible as a bullous image. Following drainage, homolateral shifts of mediastinum and four cases of pulmonary edema were recorded. Risk factors for pulmonary edema include severe pulmonary collapse with areas of atelectasis, persisting for more than 48 hours and an aspiration which either exceeded 1.5 l. of air or was performed with a depression of more than 30 cm of water.

Adolescent↗

A cell surface marker for neural crest and placodal cells: further evolution in peripheral and central nervous system.

The recent production of a monoclonal antibody (NC-1) recognizing migrating avian neural crest (NC) cells (M. Vincent, J. L. Duband , and J. P. Thiery , Dev. Brain Res. 9, 235-238, 1983) allowed us to detail their migration pathways at the trunk level of the chick embryo. Three routes can be recognized: NC cells facing the bulk of the somite accumulate to form a spinal ganglion, those facing the intersomitic space can readily reach periaortic areas to contribute to the primary sympathetic chain, and cells at intermediate levels between these two accumulate between the neural tube and the somite but some of them can escape between the sclerotome and the myotome and settle near the aorta. Histological and in vitro immunofluorescence patterns have demonstrated that the NC-1 antigen is a neuroectodermal feature. In addition to its presence on the great majority of NC cells, it persists at the surface of both neuronal and satellite cells of the peripheral ganglia. Moreover, it can be detected on neurogenic placodes and their derivatives. The appearance of the NC-1 antigen in the central nervous system coincides with the first noticeable morphological changes of the neutral tube and develops according to a rostro-caudal gradient which parallels its development: it seems, however, to be transiently expressed by the neuron cell bodies and to concentrate later on their processes. It is also present on non-neuronal cells derived from the neuroectoderm. The neuroectodermal character of NC-1 reactivity is further emphasized by its disappearance from the melanocytes and the mesectodermal derivatives of the NC. The loss by the latter, in ventral areas of the head, of the NC-1 epitope is discussed in relation to previous findings on the degree of commitment of the cephalic NC. The NC-1 epitope is associated with several high-molecular-weight polypeptides and may involve a carbohydrate moiety.

Animals↗

Urinary 6-ketoprostaglandin F1 alpha in genetically hypertensive rats of the Lyon strain.

In order to assess the pathophysiological role of renal prostacyclin in genetic hypertension, the urinary excretion of its main stable metabolite, 6-ketoprostaglandin F1 alpha, was followed in 12 hypertensive, normotensive and low blood pressure female rats of the Lyon strains at the ages of 5, 9, 21, 32 and 45 weeks. The urinary excretion of 6-ketoprostaglandin F1 alpha, which progressively decreased in the three strains between 5 and 21 weeks of age, was found to be increased in 5- and 9-week-old hypertensive rats and it was reduced in 5-week-old low blood pressure rats, compared with age-matched normotensive controls. The urinary 6-ketoprostaglandin F1 alpha was found to be significantly related to the systolic blood pressure in 5- and 9-week-old rats of the three strains (r = 0.42; n = 71; P less than 0.001). These results exclude a primary role in the development of hypertension for a genetically determined defect in the renal biosynthesis of prostacyclin in the spontaneous hypertensive rat of the Lyon strain.

6-Ketoprostaglandin F1 alpha↗