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Biomedical subjects

P Guerin

Publications and source records attributed to P Guerin.

At least 19 recordsLinked to original sources
PubMed2003

Reduction in heat-induced gastrointestinal hyperpermeability in rats by bovine colostrum and goat milk powders.

Male Sprague-Dawley rats were assigned to one of three dietary groups [standard diet (Cont; n = 8), standard diet plus bovine colostrum powder (BColost 1.7 g/kg; n = 8), or goat milk powder (GMilk 1.7 g/kg; n = 8)] to determine the ability of these supplements to reduce gastrointestinal hyperpermeability induced by heat. Raising core body temperature of rats to 41.5 degrees C increased transfer of (51)Cr-EDTA from gut into blood 34-fold relative to the ambient temperature value (P < 0.05) in the Cont group of rats, indicative of increased gastrointestinal permeability. Significantly less (P < 0.01) (51)Cr-EDTA was transferred into the blood of rats in either the BColost (27% of Cont) or GMilk group (10% of Cont) after heating, showing that prior supplementation with either bovine colostrum or goat milk powder significantly reduced the impact of heat stress on gastrointestinal permeability. The changes in the BColost group were not significantly different than those of the GMilk group. The potential mechanism of the protective effect of bovine colostrum and goat milk powders may involve modulation of tight junction permeability, because both powders were able to maintain transepithelial resistance in Madin Darby canine kidney cells challenged with EGTA compared with cells maintained in media only. The results show that bovine colostrum powder can partially alleviate the effects of hyperthermia on gastrointestinal permeability in the intact animal. Moreover, goat milk powder was equally as effective as bovine colostrum powder, and both may be of benefit in other situations where gastrointestinal barrier function is compromised.

Animals↗
PubMed2002

Coating of fertilizers by degradable polymers.

The conventional agriculture leads to some important pollution of ground water (particularly, by nitrates). The solution is the coating of fertilizers by degradable polymers. In this work, we have studied the water vapour and liquid diffusion through polymer films detached from their support. Therefore, we may classify polymers as a function of their properties like water vapour and liquid barrier. We may choose the best polymer(s) for coating.coated fertilizers by chosen polymer(s) with mechanical techniques such as fluidised bed and pan coating. Moreover, the electron microscopy used to see the quality of the wall has showed the presence of pores due to the rapid evaporation of solvent. A drying in air current and an annealing could be done to avoid this problem.followed the ions release of fertilizers immersed in distilled water by conductimetry. The more interesting result was obtained with fertilizers coated by polylactic acid. In effect, the total release reached three weeks.

Chemical Phenomena↗
PubMed2001

Towards a new functional assessment of autistic dysfunction in children with developmental disorders: the Behaviour Function Inventory.

In order to assess particular disorders of psychological development and functioning in children with developmental disorders, we have developed a new tool, the Behaviour Function Inventory (BFI), based on 11 neurophysiological functions, disorders of which are considered to contribute to the core autistic syndrome. This article reports the reliability and validity study of this new scale. Factorial analysis computed on the 55 initial items identified six main dimensions which we characterized and labelled: interaction dysfunction, praxis dysfunction, auditory dysfunction, attention dysfunction, islet of ability and emotional dysfunction. Relationships between these six new variables and diagnostic subgroups, and chronological and developmental age, are discussed. The BFI offers precise information of the functional symptomatology of autism, showing clear evidence of some disordered areas of functioning. This new approach may provide valuable information in clinical research, especially for psychopathology and physiopathology studies.

Autistic Disorder↗
PubMed2000

Bioactive functionalized polymer of malic acid for bone repair and muscle regeneration.

A bioactive poly(beta-hydroxyalkanoate) derived from malic acid was prepared and tested on bone repair and muscle regeneration. This functionalized and hydrolyzable polymer was obtained after several steps, the first one being the anionic copolymerization of three malolactonic acid esters. Chemical modifications were carried out on the terpolymer to turn benzyl-protecting groups into carboxyl groups and allyl groups into sulfonate groups. The resulting polymer bore carboxylate, sulfonate, and sec-butyl pendent groups in 65/25/10 molar proportions and were aimed at interacting with heparan binding growth factors. This polymer did not present any toxic effect in cell viability of HepG2 cells, over a large range of concentrations (0.01-0.25 mgl(-1)). Its ability to improve wound healing was tested in vivo and positive results are reported. Furthermore, the bioactivity of this polymer was evaluated using the regeneration model of Extensor digitorum longus (EDL) rat muscle. The study displayed a significant increase in the muscle regeneration and maturation.

Animals↗
PubMed1999

[Congenital left ventricular aneurysms and diverticula. Two case reports].

The authors report the cases of two young adults (25 and 27 years) presenting with congenital left ventricular aneurysm or diverticulum with healthy coronary arteries. This saccular evagination of the ventricular wall is rare. The authors describe a classification distinguishing muscular (contractile) diverticula, composed of the three cardiac tunics, fibrous diverticula and finally aneurysms with a dyskinetic wall. Although the limits of this classification are sometimes poorly defined, it presents a prognostic value, because it appears logical to propose nonsurgical management in the context of muscular diverticula and it seems legitimate to operate on fibrous diverticula and aneurysms due to the risks of rupture, extension, thrombosis or arrhythmia.

Adult↗
PubMed1998

Synthesis and polymerization of benzyl (3R,4R)-3-methylmalolactonate via enzymatic preparation of the chiral precursor.

beta-methylaspartate ammonia-lyase, EC 4.3.1.2, (beta-methylaspartase) from Clostridium tetanomorphum was used to produce a 40/60 molar ratio of (2S,3R) and (2S,3S)-3-methylaspartic acids, 2a and 2b, respectively, from mesaconic acid 1 as substrate, on a large scale. To prepare (3R,4R)-3-methyl-4-(benzyloxycarbonyl)-2-oxetanone (benzyl 3-methylmalolactonate) 6, 2a and 2b were transformed, in the first step, into 2-bromo-3-methylsuccinic acids 3a and 3b and separated. After three further steps, (2S,3S)-3a yielded the alpha, beta-substituted beta-lactone (3R,4R) 6 with a very high diastereoisomeric excess (> 95% by chiral gas chromatography). The corresponding crystalline polymer, poly[benzyl beta-(2R,3S)-3-methylmalate] 8, prepared by an anionic ring opening polymerization, was highly isotactic as determined by 13C NMR. Catalytic hydrogenolysis of lactone 6 yielded (3R,4R)-3-methyl-4-carboxy-2-oxetanone (3-methylmalolactonic acid) 7, to which reactive, chiral, or bioactive molecules can be attached through ester bonds leading to polymers with possible therapeutic applications. Because of the ability of beta-methylaspartase to catalyse both syn- and anti-elimination of ammonia from (2S,3RS)-3-methylaspartic acid 2ab at different rates, the (2S,3R)-stereoisomer 2a was retained and isolated for further reactions. These results permit the use of the chemoenzymatic route for the preparation of both optically active and racemic polymers of 3-methylmalic acid with well-defined enantiomeric and diastereoisomeric compositions.

Aspartate Ammonia-Lyase↗
PubMed1997

The mammalian oviduct: biochemistry and physiology.

Oviduct fluid and oviduct epithelium seem able to modulate in-time maturation and transport of gametes and embryos. They probably allow selection of spermatozoa through too early activation. Subtle changes in the composition of tubal secretion permit fertilization and embryo development in the best conditions. The mechanisms of these changes of oviduct fluid composition (induced by endocrine stimuli and/or by embryo) are under investigation. Numerous compounds isolated in oviduct fluid are now added to the synthetic media for in vitro maturation/in vitro fertilization/embryo culture (IVM/IVF/EC). The rationale is now to mimic more and more, the biochemical composition of tubal and uterine fluids even if interactions with embryo metabolism is still far from being understood.

Animals↗
PubMed1996

Thin melanomas with unusual aggressive behavior: a report on nine cases. Melanoma Group of French Federation of Cancer Centers.

BACKGROUND: The major factor influencing the prognosis of cutaneous malignant melanoma (MMs) is the maximum thickness of the tumor as measured by Breslow's method. However, it has been reported that thin melanomas, which should have an excellent prognosis, may have the potential to metastasize, some with an unusually rapid course. OBJECTIVE: Our purpose was to examine prognostic indicators in relation to unusually rapid aggressive behavior in patients with thin MMs (<0.76mm). METHODS: We describe nine cases of thin MM (<.76mm) that exhibited a recurrence or metastasis during a follow-up period ranging from 3 to 10 years, among computerized records of 1118 MMs treated in a multicenter epidemiologic study. The data obtained from these nine cases were compared with nonrecurring thin MM (149 cases) of the same cohort. RESULTS: The particular aggressiveness of these thin melanomas was reflected by the short disease-free interval (3 years or less) in all ine patients. The recurring thin MM more frequently involved head and neck sites, occurred in male patients, and showed Clark's level III and IV. CONCLUSION: Our review suggests that the head and neck area is particularly involved by unusually rapidly recurring thin MM. Possible explanations are the specific problems of surgical management and the greater sun exposure of this location.

Adult↗
PubMed1996

Neuropathological study of a case of autistic syndrome with severe mental retardation.

Infantile autism is a syndrome of unknown aetiology and unknown neuro-anatomic substrate. The authors report a histological study of the brain of a well-documented 16-year-old female with autistic syndrome and severe mental retardation, using direct microscopic examination of the whole brain. The major findings are low brain weight, a thin corpus callosum and ventricular dilatation. No abnormalities were found in the hippocampus or cerebellum. Excessive axonal elimination during brain development is hypothesized. The relations of hypothetical developmental events with the clinical features of autistic syndrome are discussed.

Adolescent↗
PubMed1995

Evaluation by polymerase chain reaction on the effect of beta-propiolactone and binary ethyleneimine on DNA.

Inactivating treatments for viruses such as pasteurization or alkylation by beta-propiolactone or binary ethyleneimine were tested for their capacity to modify nucleic acids. The modification of a nucleic acid was measured as the decrease in spot intensity in Southern blots after polymerase chain reaction (PCR) amplification. The inactivating treatments were applied to cellular and viral genomic material from a human lymphoblastoid cell line immortalized by Epstein Barr Virus (EBV), which produced a monoclonal antibody. Pasteurization did not modify the ability to amplify and detect cellular or viral DNA. Binary ethyleneimine strongly reduced the amount of detectable DNA and beta-propiolactone under particular conditions of incubation abolished all trace of DNA.

Alkylating Agents↗
PubMed1994

Mycobacterium avium intracellulare suppurative thyroiditis in a patient with Hashimoto's thyroiditis.

A case of suppurative thyroiditis occurring in a 72-year-old woman is reported. The clinical history of this woman, treated by tianeptine for mild exogenous affective disorder and by conventional insulin therapy for long-standing insulin-dependent diabetes, was remarkable for the pseudotumoral signs which led to the simultaneous diagnosis of hypothyroidism due to Hashimoto's thyroiditis and of mycobacterium avium intracellulare suppurative thyroiditis. To our knowledge, this is the second reported case of mycobacterium avium intracellulare thyroiditis. This case is also exemplary, given its occurrence in the absence of severe immunodepression, setting apart the mild impact on the immune system of affective disorder and of long duration's insulin-dependent diabetes.

Aged↗
PubMed1993

Theoretical aspects of the study of benzodiazepine receptors in infantile autism.

This paper is part of a special section on 'psychopharmacotherapy in children' and focuses on benzodiazepine receptors in autism. Infantile autism in an early and pervasive developmental disorder described by Kanner in 1943. Anatomical, pathological and magnetic resonance imaging studies have indicated changes in the cerebellum and hippocampus of autistic subjects. Given the numerical importance and diffuse benzodiazepine receptors, their study by functional brain imaging methods in vivo could be value in cases of infantile autism as a gauge of neuronal potentiality. The main data concerning benzodiazepine complex are presented. The relations between these data and the neurophysiological hypotheses of autism are discussed.

Adolescent↗
PubMed1993

[Scales and questionnaires for the evaluation of behavior disorders in children].

The need for quantitative clinical evaluation tools for use in child psychiatry is obvious. Behavior rating scales are useful for comparing clinical and laboratory data, monitoring the effects of treatments, and enhancing communication between clinicians and investigators. The methodological principles used to construct and validate such tools are described. This approach is of benefit in most psychiatric disorders of children and adolescents. The questionnaires and scales most widely used throughout the world and available in French are reviewed. The advantages and drawbacks of evaluation scales in everyday practice and in research are discussed, with the BSE-A scale (Behavior Summarized Evaluation of Austism) as an example.

Adolescent↗
PubMed1988

Measles virus-induced suppression of lymphocyte proliferation.

The mechanism by which measles virus induces immunosuppression was investigated using an in vitro system employing phytohemagglutinin (PHA)-induced human peripheral mononuclear cell (PBMC) proliferation. At a multiplicity of infection of 1.0 or greater measles virus significantly inhibited (45%) the proliferation of PBMC. This inhibition was not due to an alteration in the kinetics of proliferation. PHA-stimulated PBMC were then infected with measles virus for 72 hr and irradiated (3200 rad) to prevent further proliferation. These infected, irradiated PBMC when added to fresh autologous PBMC caused significant inhibition of lymphoproliferation over a wide range of infected:fresh cell ratios (maximum inhibition seen at a 1:1 ratio, 85% inhibition). Virus recovered from the irradiated, infected cells was 100-fold lower than the virus titer needed to cause inhibition by direct addition of measles virus. However, antibody to measles virus reversed the inhibition. Virus-free supernatant fluids from the infected irradiated cells caused immunosuppression of the PHA response. This immunosuppressive material induced by the measles virus was maximally produced after 72 hr and did not appear to require viral replication. This factor was not prostaglandin E or interferon-alpha or -gamma. The production of such suppressive factors during viral infection may explain some of the profound immunosuppression seen in situations in which little or no infectious virus can be detected.

Animals↗
PubMed1988

[The Pont Neuf].

Explore the source record for details and available documents.

France↗
PubMed1983

Effect of methylmercuric chloride on gangliosides of mouse neuroblastoma cells in culture.

The effect of methylmercuric chloride (CH3HgCl) on the levels of gangliosides in mouse neuroblastoma cells (NBP2) in culture was studied. The treatment of NB cells with low concentrations (0.1 microM and 0.2 microM) of CH3HgCl, which did not affect the growth rate or morphology, caused an increase in the level of the GM3 ganglioside without changing the level of other gangliosides. The treatment of NB cells with higher concentrations (0.5 microM and 1 microM) of CH3HgCl, which inhibited the growth of NB cells, caused a decrease in the level of GM3 and an increase in the level of GM2. These results show that alterations in the levels of specific gangliosides can be observed in cells which do not exhibit any detectable change in growth rate or morphology. This change may be associated with subtle changes in brain functions, including behavioral and psychological changes, after exposure to low concentrations of organic mercury.

Animals↗