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Biomedical subjects

F Mathieu

Publications and source records attributed to F Mathieu.

66 records · Page 4Linked to original sources
PubMedDate not supplied

Transepithelial transport of bepridil in the human intestinal cell line, Caco-2, using a "dynamic model".

The purpose of the study was to go further into the transepithetial transport of bepridil, an anticalcic agent, through monolayer cells Caco-2, using a "dynamic model" including a transfer of inserts with Caco-2 cells into new wells, free of drug, at regular intervals, in order to simulate the blood flux. The state of cells was evaluated by measuring the transepithelial electrical resistance and the transport of bepridil was followed using a gas chromatography/mass spectrometry determination. This study exhibits the importance of the basolateral renewal both on the transport of bepridil and the maintenance of cells in a satisfactory state. Two elimination phases from the cell compartment seem to occur, with basolateral half lives respectively of 12.2 and 25.6 hours, probably linked with two kinds of cellular binding sites. This dynamic model permits the reflection and simulation of the slowness of the in vivo absorption of bepridil in the small intestine.

Bepridil↗
PubMedDate not supplied

Influence of different calcic antagonists on the Caco-2 cell monolayer integrity or "TEER, a measurement of toxicity?".

The purpose of this work was to investigate the interest of the TEER measurement, a quite simple measure, as an evaluation of toxicity, in function of time and level of drug in the experimental medium, for different anticalcic agents. The extend of the increase and decrease of TEER, was evaluated by measuring the TEERmax and calculating the TEER50 respectively. Three groups of compounds could be therefore considered. The first, characterized by a quite short period of TEER increase, followed by an extremely rapid decrease (high values of TEER50), included perhexiline and prenylamine. The most toxic compounds, the second one, characterized by the smallest variations of TEER, included verapamil and diltiazem. This group was related with the less toxic compounds, the third group, represented by bepridil, characterized by dependant-dose TEERmax and TEER50. Therefore, the TEER measurement appeared as a quite simple approach of comparative toxicity of anticalcic agents.

Bepridil↗
PubMedDate not supplied

The effect of Saccharomyces cerevisiae and Aspergillus oryzae on the digestion of the cell wall fraction of a mixed diet in defaunated and refaunated sheep rumen.

The objective of this study was to determine the effect of two probiotics, Saccharomyces cerevisiae (SC) and Aspergillus oryzae (AO), without their culture medium, on the digestion of plant cell wall components in sheep that had been successively defaunated and refaunated. Six sheep fitted with large rumen cannulae were used to study 1) defaunated sheep with no probiotic, 2) defaunated sheep with SC or AO, 3) refaunated sheep with no probiotic, 4) refaunated sheep with SC or AO. The apparent digestibility of the plant cell walls was not altered (P > 0.05) by the probiotics in defaunated sheep but was increased (P < 0.05) with SC (+16%) in refaunated sheep. Simultaneously, SC stimulated the growth of the protozoal population in the rumen. As noted in most previous experiments, the positive effect of the presence of protozoa on plant cell wall digestion (P < 0.001) was confirmed here. The effect (P > 0.05) of SC or AO on in situ ADF digestion was either not significant or negative in defaunated rumens, whereas it became positive in refaunated rumen after a residence time of 12 h. The improvement of in situ ADF digestion due to the presence of protozoa was significant (P < 0.05 for NDF; P < 0.001 for ADF). However, we could not determine whether this was a direct effect of protozoa or an indirect effect operating via bacteria. The limits of the nylon bag technique for evaluating the microbial activity are discussed in relation to the ability of protozoa to enter and grow in the bags, and the pH regulation inside the bags. The pH values below 5.5 noted inside the bags can significantly alter the bacterial and protozoal populations and limit the validity of the technique. SC increased (P < 0.05) the specific activity of CMCase and xylanase of the solid-adherent bacteria (SAB) isolated from the rumen digesta of refaunated sheep. Stimulation of both the bacterial activity and protozoa numbers could explain the positive effect of SC on cell wall digestion in the rumen since the modelling of marker excretion in faeces showed that the ruminal mean retention time of hay measured from the model of Danhoa et al. was not modified (P > 0.05) by either refaunation or the presence of probiotics. AO increased (P < 0.05) the total retention time of the solid particles in the whole digestive tract and increased the ruminal liquid volume in the refaunated animals but it had no effect on the protozoa population or on the polysaccharidase activity of the SAB, which could explain the absence of effect of AO on the total digestibility of plant cell walls. Both probiotics decreased the liquid turnover in defaunated rumens (P < 0.05) but neither had any effect (P > 0.05) on this parameter after refaunation. The improvement of plant cell wall degradation in the whole digestive tract is probably due to a stimulation of digestion at the rumen level as indicated by the higher activity of the SAB in rumen digesta and the growth of protozoa.

Animal Feed↗
PubMedDate not supplied

Analysis of lipid composition of sarcoplasmic reticulum membranes from normal and malignant hyperthermic pig skeletal muscle.

In search of a general membrane defect hypothesis for malignant hyperthermia syndrome, we analysed the lipid profiles of heavy sarcoplasmic reticulum membranes isolated from normal and malignant hyperthermia longissimus dorsi pig muscle. Malignant hyperthermia susceptibility was assessed by halothane challenge of pigs. Sarcoplasmic reticulum membranes from malignant hyperthermia susceptible pigs differed significantly from control ones in the cholesterol content and phosphatidylethanolamine/phosphatidylcholine ratio; both were higher in former membranes. These latter lipid modifications were in agreement with the significant increase of their bulk lipid viscosity, as evidenced by an increase of diphenyl hexatriene fluorescence anisotropy. The increased level of phosphatidylethanolamine associated with the decreased content of phosphatidylcholine in malignant hyperthermic membranes was shown to be a potential consequence of depressed activities of both phospholipid N-methyltransferase I and II activities. Finally, the distribution of fatty acids in these particular phospholipids showed no change in phosphatidylcholine molecules, whereas the percentage of arachidonate and stearate in the phosphatidylethanolamine species were respectively higher and lower in malignant hyperthermic membranes. These differences in major phospholipids content and the enrichment of a metabolically important fatty acyl chains in malignant hyperthermia sarcoplasmic reticulum membranes strongly suggest that the lipid metabolism may contribute to the molecular mechanism of malignant hyperthermia syndrome.

Animals↗
PubMedDate not supplied

[Therapeutic trials in schizophrenia with dialysis. State of the art and one case study (author's transl)].

The literature reveals 184 cases of chronic schizophrenia treated with dialysis, of which 51 with a good result. Success seems more frequent in women. Methodologies are often not well controlled, with poor clinical description. No confirmation of endorphin secretion can be found. However, positive results in some centers should stimulate more researches. Retrospective studies of available cases should be done to determine characteristics of responders. We have elaborated a questionnaire to select such responder patients and design controlled or cross-over studies. A placebo effect is possible in light of the magic and suggestive impact of such procedure. A mean aged 27 years, delusional for 9 years despite high doses of neuroleptics, was not helped by dialysis.

Adult↗
PubMedDate not supplied

[Diabetes and road safety].

The purpose of this study is to analyse the driving habits of a group of diabetic individuals, insulin and noninsulin treated, compared with the driving habits of an equivalent group of individuals in good health. Specific attention is given to the evaluation and management of stress related to driving. The analysis relies mainly upon the answers of 307 persons of both sex on a questionnaire regarding their driving habits and concerning twenty more or less risky behaviors. The diabetic subjects were sampled among the patients of an endocrinology clinic, and the pilot group (in good health) was gathered among the patients from the clinic of a general practitioner. The subjects were aged between 25 and 65. All were in possession of a driving licence and had a driving experience of over two years. The results show, on one hand, that the evaluation of stress related to a risky behavior is associated to the taking of risk at the wheel, and on the other hand, that compared with the other subjects in the study the diabetic subjects had a lesser tendency to taking risks in driving. The subjects avoided the behaviors they judged risky. Beside avoiding dangerous road behaviors, the latter brought special attention to food and relaxation needs and they showed a great alertness towards climatic and road conditions. Finally, they are especially careful in preventing and curing hypoglycaemic states.

Adult↗
PubMedDate not supplied

[The Bourdaloue urinal in all its forms].

The author draws the attention of his urologist as well as nonurologist colleagues to the "Bourdaloue" urinal describing its dual aspect of a utilitarian and artistic object. A rapid study situates it in its particular historical context and in the more general context of urine collection bottles.

Ceramics↗