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Biomedical subjects

M Vincent

Publications and source records attributed to M Vincent.

At least 271 records · Page 15Linked to original sources
PubMed1986

[Effect of the thymus on the development of genetic hypertension in the Lyons-strain rat (LH)].

The aim of this work was to determine the part played by the thymus in the development genetic hypertension. This study was conducted in the genetically hypertensive rats (LH) of the lyon strain and their two simultaneously selected controls: the normotensive (LN) and low blood pressure (LL) rats. Systolic blood pressure (SBP) and immunological characteristics were investigated in sham-operated and neonatally thymectomized rats of the 3 strains. At 5 weeks of age, sham-operated LH rats exhibited a higher SBP (122 +/- 4 mmHg) than LN (111 +/- 2 mmHg) and LL (100 +/- 2 mmHg) controls. White blood cell numbers and percentage of circulating lymphocytes, thymus histology as well as T cells and T subsets percentages in that organ did not significantly differ within the 3 strains. On the contrary, in the animals of the 3 strains, a positive relationship could be established between the SBP and the proliferative response of the splenocytes to Pokeweed-Mitogen (r = 0.93; N = 30; p less than 0.001) or to Concanavalin A (r = 0.42; n = 30; p less than 0.05). After neonatal thymectomy the SBP of LH rats was more markedly decrease than that of LN and LL rats and established as follows: 103 +/- 2 mmHg; 102 +/- 2 mmHg; 97 +/- 2 mmHg for LH, LN and LL respectively. 21 weeks after thymectomy the SBP remained significantly decrease in LH rats only 160 +/- 5 mmHg vs 177 +/- 6 mmHg in sham-operated rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Cardiac and renal hyperplasia in newborn genetically hypertensive rats.

Newborn spontaneously hypertensive rats (SHR), compared with Wistar-Kyoto (WKY) controls, usually show cardiac and renal hyperplasia. To determine whether these anomalies are common to genetically hypertensive rats, we examined newborn rats from models of essential hypertension (Kyoto, Montreal, Dunedin and Lyon strains of hypertensive rats), renal hypertension (Milan strain of hypertensive rats) and experimental hypertension [deoxycorticosterone acetate (DOCA)-salt hypertensive Wistar rats]. The hearts, kidneys and livers of these newborns were collected on site at various centres and sent to Montreal for protein and DNA determinations. The results showed that protein and DNA, corrected for body weight in models of essential hypertension, were increased in the heart and kidney, and normal or decreased in the liver at birth. This pattern differed in offspring of the Milan strain (renal hypertension) and of DOCA-salt hypertensive animals (experimental hypertension). Since cardiac and renal hyperplasia associated with the hypertensive trait in four different genetic models of spontaneous hypertension was distinct from that observed in renal and experimental hypertension, it is conceivable that a specific cardiovascular growth pattern is a reflection not of a simple linkage or consequence, but of a causal association with spontaneous hypertension.

Animals↗
PubMed1986

[Urinary excretion of thromboxane B2 in the genetically hypertensive rat of the Lyons strain].

In order to assess the pathophysiological role of the renal Thromboxane (Tx)A2 in genetic hypertension, the urinary excretion of its stable metabolite: the TxB2 was followed in groups of 12 hypertensive (LH), normotensive (LN) and low blood pressure (LL) female rats of the Lyon strains at the ages of 5, 9, 21 and 32 weeks. In the 3 strains studied, the urinary TxB2 excretion markedly decreased between 5 and 9 weeks of age and did change thereafter. In addition, 5 and 9 weeks old rats exhibited an increased urinary TxB2 output compared to LN and LL controls. Since TxA2 is a potent vasoconstrictor, it seems likely to hypothesize that the early increase observed in the renal TxA2 biosynthesis could be one of the primary events occurring during the development of hypertension in this rat model.

Aging↗
PubMed1986

Effect of swim training on systolic blood pressure, vasopressin and total neurophysins in the Lyon hypertensive rat.

This study reports the effects of 5 weeks of swim training on systolic blood pressure, body weight, plasma and brain vasopressin and total neurophysins in the Lyon genetically hypertensive (LH) rat and in their normotensive (LN) and low blood pressure (LL) controls. Swimming was unable to influence any studied parameters. These results shed doubt on the efficiency of this model of training on the evolution of hypertension in the LH rats.

Animals↗
PubMed1986

Antihypertensive effect of neonatal thymectomy in the genetically hypertensive LH rat.

Genetically hypertensive (LH), normotensive (LN), and low blood pressure (LL) rats of the Lyon strains have been simultaneously selected according to their systolic blood pressure (SBP). SBP and immunological parameters were investigated in 5 week-old rats. SBP reached 99 +/- 2 mmHg in LL, 108 +/- 2 mmHg in LN and 122 +/- 4 mmHg in LH. White blood cell and lymphocyte counts, thymus and spleen histology, percentages of T cells and subsets of T cells in these organs were not modified by genetic hypertension. The blastogenic responses to mitogens (Con A and PWM) of the LH rat thymocytes were similar to those observed in LN or LL rats. By contrast, the proliferative response of splenocytes to PWM was positively correlated (r = 0.93) with SBP level. In additional experiments we demonstrated that, besides the immune defect induced by neonatal thymectomy, the removal of the thymus at birth prevented the spontaneous increase of SBP in LH strains (102 +/- 2 mmHg instead of 122 +/- 4 mmHg), while only a slight decrease or no alteration was seen in LN and LL thymectomized rats. This antihypertensive effect tended to maintain SBP at a common level in the 3 strains. These results suggest that the thymus may be involved in the development of genetic hypertension.

Animals↗
PubMed1986

In vitro and in vivo effects of a monoclonal antibody-toxin conjugate for use in autologous bone marrow transplantation for patients with breast cancer.

We have devised a method utilizing a monoclonal antibody-toxin conjugate (LICR-LON-Fib75/abrin A-chain) for ridding bone marrow of infiltrating breast cancer cells to rescue patients with autologous bone marrow following high dose therapy. Initially we examined the activity of this conjugate in vitro. Five of seven human breast cancer cell lines were killed following exposure at 10(-8) M for 2 h; this concentration only reduced bone marrow colony formation to 83% (range, 50-100%) of control bone marrow. We then examined the pattern of bone marrow recovery after high dose melphalan (200 mg/m2) in patients with advanced breast cancer who were in remission following combination chemotherapy. To do this we compared the time of recovery of the blood count in three patients who received treated marrow and seven who received untreated marrow. Mean time to recovery of the peripheral white count (greater than 1.5 X 10(9)/liter) was 16.7 days (treated) and 18.3 days (untreated), respectively. Mean time to recovery of peripheral platelet count (greater than 50 X 10(9)/liter) was 23.7 days (treated) and 18.9 days (untreated), respectively. Patients continued in remission for 1-greater than 14 mo after high dose melphalan, and remission duration was similar in patients who received treated (6.2 mo) and untreated (7.3 mo) bone marrow. These findings indicate that treatment of bone marrow with LICR-LON-Fib75/abrin A-chain conjugate does not significantly impair bone marrow recovery, and it is, therefore, possible to rescue breast cancer patients with bone marrow that has been cleansed of infiltrating cancer cells. This may have an application in patients with poor-risk primary breast cancer who have micrometastases and who may benefit from intensive therapy, but it has minimal application in patients with more advanced disease.

Abrin↗
PubMed1986

[Epidemiology of postoperative infections in cervicofacial surgery].

Post-operative infections are studied about 150 patients distributed in five groups according to type of surgery (total pharyngolaryngectomy, hemilaryngectomy, bucco-pharyngectomy, cordectomy, cervicotomy). An antibiotic prophylaxis by penicillin G and metronidazole was prescribed for all groups excepted the last. Only sixteen patients (seven of whom in bucco-pharyngectomy group) developed a local infection, therefore these antibiotics are indicated until mucosa cicatrisation. Systematic bacteriologic study of cervical drains is useless because they are frequently positive with non-pathogenic germs and in case of local infection the responsible germ is different of the germ obtained by culture of drain.

Anti-Bacterial Agents↗
PubMed1986

[Effects of 2 metal salts (FeCl3, CuCl2) on predatory activity and egg laying of Zonitoides nitidus Müller (Mollusca, Gastropoda, Pulmonata)].

Laboratory observations were made on the effects of two metal salts, FeCl3 and CuCl2, on the life of a terrestrial predatory snail, Zonitoides nitidus. These effects were studied, either by direct dipping of predators in the salts with the study of their predation on living lymnaeid snails during the 10 days after dipping, or by exposure of intoxicated, living snails to predators during 28 days. The number of eaten preys and the number of egg laids steadily decreased in the Z. nitidus groups dipped in the toxics during more and more long times. The same results were observed in the Z. nitidus groups eating intoxicated preys after day 7 of experiment. More toxic effects were obtained in all the egg laids of predators in contact with CuCl2 than with FeCl3. The significance of these results is discussed in relation with the joint and alternate control of L. truncatula by chemical and biological means.

Animals↗
PubMed1986

[Comparative study of the toxicity of metal chlorides and a synthetic organic molluscacide, N-tritylmorpholine, in 2 fresh-water amphipods, Gammarus pulex and Echinogammarus berilloni].

The effects of three metal salts (BaCl2, CuCl2, ZnCl2) and of N-trityl-morpholine (Triphenmorph) were studied on two aquatic amphipod species, Gammarus pulex and Echinogammarus berilloni. Experiments were made up in eucalcic and oligocalcic waters for determining the LC50 at different exposure times. The order of toxicity was the same in eucalcic water with the two species: Triphenmorph greater than Cu2+ greater than Zn2+ greater than Ba2+. This order was the same in oligocalcic water with Echinogammarus berilloni; with Gammarus pulex, CuCl2 was more toxic than Triphenmorph.

Animals↗
PubMed1985

Membrane proteins in reverse micelles: myelin basic protein in a membrane-mimetic environment.

The solubility, reactivity, and conformational dynamics of myelin basic protein (MBP) from bovine brain were studied in reverse micelles of sodium bis(2-ethylhexyl) sulfosuccinate (AOT)-isooctane and water. Such a membrane-mimetic system resembles the aqueous spaces of native myelin sheath in terms of physicochemical properties as reflected in the high affinity of MBP for interfacial bound water. This is marked by the unusual profile of the solubility curve of the protein in reverse micelles, which shows optimal solubility at a much lower molar ratio of water to surfactant ([ H2O]/[AOT] = w0) than that reported for other water-soluble proteins. The role of counterions and/or charged polar head groups in the solubilization process is revealed by comparison of the solubility of MBP in nonionic surfactant micellar solutions. Whereas MBP is unfolded in aqueous solutions, insertion into reverse micelles generates a more folded structure, characterized by the presence of 20% alpha-helix. This conformation is unaffected by variations in the water content of the system (in the 2.0-22.4 w0 range). The reactivity of epsilon-amino groups of lysine residues with aqueous solutions of o-phthalaldehyde demonstrates that segments of the peptide chain are accessible to water. Similar results were obtained with the sequence involved in heme binding. In contrast, the sole tryptophan residue, Trp-117, is shielded from the aqueous solvent, as indicated by lack of reaction with N-bromosuccinimide. The invariance of the wavelength maximum emission in the fluorescence spectra as a function of w0 is consistent with this result.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Cardiolipin vesicles can accommodate cholesterol up to 0.80 mole fraction, i.e. one molecule per cardiolipin fatty acid chain.

Cardiolipin-cholesterol interactions were studied by time-resolved fluorescence spectroscopy with 1,6-diphenyl-1,3,5-hexatriene as probe. The residual anisotropy parameter, r infinity (reflecting the fatty acid chain packing), was measured in the liquid crystalline phase as a function of cholesterol addition. Two main results are reported: (i) a slight increase of the order parameter, S, computed from the r infinity value as S = (r infinity/r0)1/2, in the physiological concentration range of cholesterol; (ii) a sharp enhancement of S from a cholesterol mole fraction (X chl) of 0.20 and up to X chl of 0.80. This is in contrast to unsaturated lecithin systems for which a continuous increase of the order parameter was monitored, culminating at X chl = 0.50, the well-known maximum level of incorporation of cholesterol into lecithin model membranes.

Animals↗
PubMed1985

Patterns of relapse in locally advanced head and neck cancer patients who achieved complete remission after combined modality therapy.

Relapse patterns in patients with locally advanced head and neck cancer who achieved complete remission were evaluated. After combined modality therapy with induction chemotherapy followed by surgery and/or radiotherapy, 71 of 103 patients were clinically free of disease. The 5-year recurrence rate was estimated at 51%, with a 39% local and 26% distant failure rate by 5 years. The factors significantly affecting the relapse patterns were: the site of the primary tumor (those with oral cavity lesions were more likely to fail locally, whereas hypopharynx patients had a higher risk of distant metastases); the type of definitive local treatment (those patients who received surgery and radiotherapy were at lower risk of pure local failure); TN Stage (patients with T4N3 or T3N3 tumor were at higher risk of both local and distant failure); and time to response and presence of oropharyngeal lesions (patients who had a longer period from diagnosis to final complete response [CR] and patients with oropharyngeal primaries were at higher risk for simultaneous local and distant failure). Type of chemotherapy, patient age, tumor differentiation, and response to induction chemotherapy did not significantly influence the patterns of relapse. A combined modality approach with induction chemotherapy, surgery, and/or radiotherapy does not seem to reduce the incidence of distant metastases significantly.

Adult↗
PubMed1985

Brain, spinal cord and adrenal catecholamine concentrations in neonate rats of the Lyon hypertensive strain.

The catecholamine concentrations were determined in brain parts, spinal cord and adrenals of neonate hypertensive rats of the Lyon strain (LH), compared to normotensive (LN) and low-blood-pressure (LL) control rats. In adrenals of LH rats, noradrenaline and adrenaline concentrations are increased, and 3,4-dihydroxyphenylacetic acid (DOPAC) concentration decreased. At the central level, the DOPAC concentration and the ratio DOPAC/dopamine are decreased in the mesencephalon and the forebrain of LH rats. These results suggest that neonate LH rats exhibit a decreased activity in central dopaminergic neurons, and an enhanced maturation of the adrenals.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1985

Steady-state and time-resolved fluorescence anisotropy study of phospholipid molecular motion in the gel phase using 1-palmitoyl-2-[9-(2-anthryl)-nonanoyl] -sn-glycero-3-phosphocholine as probe.

1-Palmitoyl-2-[9-(2-anthryl)-nonanoyl]-sn-glycero-3-phosphocholine (Anthr-PC), a non-perturbing phospholipid probe [de Bony, J. and Tocane, J. F. (1983) Chem. Phys. Lipids 32, 105-121], has been designed in order to obtain insight into the membrane lipid organization at a 'microscopic' level, in terms of lateral distribution both in model and in natural membranes [de Bony, J. et al. (1984) Eur. J. Biochem. 143, 373-379; FEBS Lett. 174, 1-6]. In the present study, the molecular motions of this new fluorescent probe embedded in a lipid matrix have been investigated by fluorescence anisotropy techniques in steady-state and time-resolved modes. The results indicate that long axis rotation, monitored by the out-of-plane mode of rotation of the fluorophore, is fast even in the phospholipid gel state. It is moderately sensitive to the phase transition. The data suggest that this rotation is anisotropic. Cholesterol exhibits little effect on this rotation. The rotation of the long axis itself is sensitive to the transition. It is hindered as inferred from measurements at wavelength where both the in-plane and out-of-plane motions contribute to the depolarization of the emitted fluorescence light. Cholesterol restricts this motion. The behaviour of the free 9-(2-anthryl)-nonanoic acid is not significantly different from that of Anthr-PC. These results are discussed with respect to the influence of orientational constraints on the photodimerization process when this lipid probe is used to monitor phospholipid lateral distribution.

Fluorescence Polarization↗
PubMed1985

How do the migratory and adhesive properties of the neural crest govern ganglia formation in the avian peripheral nervous system?

The peripheral nervous system derives mainly from the neural crest both in the head and trunk. Using markers such as fibronectin (FN), neural cell-adhesion molecule (NCAM), the nucleolar marker for quail cells in chimaeric embryos, and NC-1, a monoclonal antibody specific to crest cells and their neural derivatives, we have attempted to reconstruct the processes that lead to the formation of peripheral ganglia. Our observations allow us to propose a model of the formation of ganglia based on morphogenetic movements and on variations of crest cell adhesiveness. In most cases, crest cells migrate in morphologically defined and transient pathways that lead them to their final site of arrest; these pathways are always associated with FN, which appears necessary for crest cell attachment and movement in vitro. The directionality of crest cell migration is probably dictated by the cells' motile properties and population pressure in restricted areas suitable for cell movement. The disappearance of the pathways and of the substrate necessary for migration while the population is rapidly dividing may be responsible for the aggregation of crest cells in the case of the sensory ganglia. To the contrary, the aggregation of crest cells into autonomic ganglia (sympathetic, enteric, and ciliary ganglia) does not seem to obey the same rules, no disappearance of the substratum or of the pathways being obvious; rather, their formation seems correlated with the de novo synthesis of adhesive molecules such as NCAM.

Animals↗