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Biomedical subjects

P Gaucher

Publications and source records attributed to P Gaucher.

At least 19 recordsLinked to original sources
PubMed2006

Fine grains ceramics of PIN-PT, PIN-PMN-PT and PMN-PT systems: drift of the dielectric constant under high electric field.

Lead-based ferroelectric ceramics with (1-x)Pb(B1 B2)O3-xPbTiO3 formula have emerged as a group of promising materials for various applications like ultrasonic sonars or medical imaging transducers. (1-x)PMN-xPT, (1-x)PIN-xPT and ternary solutions xPIN-yPMN-zPT ceramics are synthesised using the solid state reaction method. Our objective is to achieve higher structural transition temperatures than those of PMN-PT ceramics with as good dielectric, piezoelectric and electromechanical properties. Ceramics capacitance and loss tangent are measured when the ac field of measurement increases up to E=500 V/mm. Behaviours of these materials under ac field are related to their coercive field and Curie temperature.

Journal Article↗
PubMed2005

A new rhabdiasid nematode, Chabirenia cayennensis n. g., n. sp., parasitic in the glands of the buccal mucosa of a South American saurian.

Chabirenia cayennensis n. g., n. sp. (Nematoda: Rhabdiasidae) is described from the teiid lizard Ameiva ameiva. A total of 139 worms were recovered, all females, from the mucous glands of the buccal cavity. The worm has a free-living phase in a homogonic life-cycle. Infective larvae are enclosed in a sheath with chequered ornamentation and composed of two exuviae. The new genus is distinct from the five known genera of the family, Pneumonema Johnston, 1916, Acanthorhabdias Pereira, 1927, Entomelas Travassos, 1930, Rhabdias Stiles and Hassall, 1905 and Neoentomelas Hasagawa, 1989, in the following characters: helical habitus, longitudinal cuticular crests, very tiny buccal cavity without thick walls and three oesophageal onchia. Several characters of this new rhabdiasid suggest the Strongylida.

Animals↗
PubMed2003

Mercury in canopy leaves of French Guiana in remote areas.

A study of total Hg concentration in the foliage of the canopy was carried out in two remote areas in French Guiana. The sampled canopy is representative of the French Guiana canopy. The concentration in the foliage, 64+/-14 ngg(-1) (dry wt.), is used to estimate the annual input of total Hg to the soil through the litterfall, found to be 45+/-10 microgm(-2)y(-1). As translocation is negligible, mercury in the canopy originates mainly from atmospheric uptake by the leaves and this litterfall deposit represents a direct atmospheric input from the background atmospheric load into the soil.

Air Pollutants↗
PubMed2001

Interferon alpha therapy in haemophilic patients with chronic hepatitis C: a French multicentre pilot study of 58 patients.

BACKGROUND AND OBJECTIVES: Information about the long-term efficacy of interferon alpha (interferon-alpha) in haemophilic patients with chronic hepatitis not co-infected with the human immunodeficiency virus (HIV-1) is still limited. Previous studies seemed to indicate a low rate of response. The aim of this study was to evaluate the safety and long-term efficacy of interferon treatment in multi-transfused haemophiliacs. METHODS: Fifty-eight haemophiliacs were scheduled to receive 3 MU of interferon-alpha 2b three times a week for 12 months. The patients were followed up for at least 24 months post-treatment. Response was assessed by measurements of serum hepatitis C virus (HCV) RNA. RESULTS: Twenty-four patients (41.4%) dropped out. Except for seven patients, the symptoms that led to interrupting interferon treatment would probably not have resulted in the same decision in non-haemophilic patients. One patient developed an inhibitor to the deficient clotting factor without haemorrhagic consequences. In an intent to treat, the sustained virological response rate was 14%. However, when considering only the 34 patients who received the full treatment, HCV-RNA was cleared in eight patients (23%). CONCLUSIONS: This study suggests that multi-transfused haemophiliacs with chronic hepatitis not co-infected with HIV-1 respond to prolonged treatment with interferon-alpha in a similar proportion to that observed in non-haemophiliacs. There was a high rate of patients who did not complete the interferon-alpha treatment, and this seems to be characteristic of this patient population.

Adolescent↗
PubMed1997

Alcoholic cirrhosis and cobalamin metabolism.

The cobalamin status of 27 patients suffering from alcoholic cirrhosis and 20 control subjects was analyzed. Plasma cobalamin (p < 0.005), total corrinoids (p < 0.005) and their analogs (p < 0.05) were all significantly elevated in the cirrhosis patients. These differences were due to increased haptocorrin (HC)-bound corrinoid (p < 0.02), which could be explained by a deficient hepatic clearance of cobalamin bound to HC. The increase in the concentration of true cobalamin was greater than that of its analogs. There were positive correlations between cholestasis (serum alkaline phosphatase) and plasma analog concentrations (p < 0.05), HC-bound cobalamin (p < 0.005) and total corrinoids bound to HC (p < 0.005). The plasma concentrations of the indicators of cobalamin deficiency, homocysteine (p < 0.05) and methylmalonic acid (p < 0.001), were increased, which could indicate poor cellular penetration of vitamin B12 or a defect in the activation of the two vitamin-B12-dependent enzymes.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1996

Crohn's disease and vitamin B12 metabolism.

The concentrations of vitamin B12, its analogs, and the haptocorrin and transcobalamin carriers in 21 patients suffering from Crohn's disease and a group of controls (20 adults) were measured. There were no significant differences in the mean values for vitamin B12, total corrinoids (vitamin B12 + analogs), or vitamin B12 or total corrinoids bound to haptocorrin or transcobalamin of the Crohn's and control patients. There was a significant increase in the binding capacity of transcobalamin in the Crohn's patients compared to the controls (P < 0.001), but there was no difference in the binding capacities of haptocorrin. The serum concentrations of the markers of vitamin B12 status, homocysteine and methylmalonic acid, showed an increase (P < 0.01) in homocysteine in the Crohn's disease patients, but no change in methylmalonic acid. As the hyperhomocysteinemia was associated with normal folate concentrations, there may have been a defect in the activation of the enzyme due to altered intracellular vitamin B12 status.

Adult↗
PubMed1996

Comparison of resection, liver transplantation and transcatheter oily chemoembolization in the treatment of hepatocellular carcinoma.

BACKGROUND/AIMS: Resection and liver transplantation are currently considered as the most useful treatments for hepatocellular carcinoma. However, transcatheter oily chemoembolization may be favourably compared with these two surgical treatments in patients with anatomically operable tumors. METHODS: Between 1985 and 1991, 122 patients with an Okuda stage I tumor were hospitalized in two French hospitals. Among these patients, 33 remained untreated, 42 were treated by transcatheter oily chemoembolization, 30 by resection and 17 by liver transplantation. The four groups were closely comparable except for age, the patients in the two surgical groups being significantly younger. Moreover, the frequency of pTNM II tumor was significantly higher in the resection group. RESULTS: The 5-year probability of survival was close to 45% in each of the three treated groups and was significantly higher than in the untreated group (0% at 4 years, p < 0.0001). The probability of cancer recurrence and/or metastatic dissemination was lower after transcatheter oily chemoembolization than after surgery. CONCLUSION: Thus, transcatheter oily chemoembolization seems comparable at 5 years with resection or transplantation for the treatment of resectable hepatocellular carcinoma.

Aged↗
PubMed1995

[Agenesis of the right lobe of the liver and portal hypertension].

A case of agenesis of the right lobe of the liver associated with portal hypertension is reported. This uncommon feature was diagnosed by computed tomography which excluded secondary liver atrophy due to cirrhosis or tumour. The main pathophysiological hypothesis for agenesis and portal hypertension, exceptionally associated, is arrest of hepatic development during foetal life.

Humans↗
PubMed1994

Studies on peroxisomes of colonic mucosa in Crohn's disease.

The etiology and pathogenesis of Crohn's disease, a chronic inflammatory bowel pathology, have not been elucidated yet. In particular, the behavior of peroxisomes in inflamed colonic mucosa has not been investigated despite their important role in cellular oxidative metabolism. Using cytochemistry at the ultrastructural level, we have observed these catalase-positive organelles. In addition, biochemical analyses have revealed the specific activities of catalase and cyanide-insensitive acyl-CoA oxidase. Mucosal biopsy specimens from inflamed and noninflamed areas of Crohn's patients were compared to control biopsies. We found that Crohn's disease was marked by an important diminution in the peroxisomal frequency per cell unit area. If catalase activity was not affected by this pathology, cyanide-insensitive acyl-CoA oxidase, an enzyme of the peroxisomal beta-oxidation system, was found diminished in inflamed and in noninflamed areas. In conclusion, our results showed that Crohn's disease is accompanied by peroxisomal modifications but the number and the enzyme activities of colonic peroxisomes are less deeply altered in Crohn's disease than during neoplasia. This fact suggests that a relation may exist between the degree of peroxisomal deficiency and the clinical severity of colonic disease.

Acyl-CoA Oxidase↗
PubMed1994

Artificial insemination in Houbara bustards (Chlamydotis undulata): influence of the number of spermatozoa and insemination frequency on fertility and ability to hatch.

Between 1989 and 1992, artificial insemination was used in the reproduction of two subspecies of Houbara bustard (Chlamydotis undulata macqueenii and Chlamydotis undulata undulata) at the National Wildlife Research Center, Taif. The laying period was between January and July and the mean annual egg production in C. undulata macqueenii was 10.2 and in C. undulata undulata was 7.6. No differences were found in sperm production between the two subspecies: the mean volume of ejaculate was 0.08 ml; the mean sperm concentration was 350 x 10(6) spermatozoa ml-1; and the mean number of spermatozoa per ejaculate was about 20 x 10(6). Large intra- and inter-individual variation was found in sperm parameters. Intra-individual variation in number of spermatozoa per ejaculate was due mainly to seasonal variation. The mean quantity of spermatozoa produced per week by fully sexually mature Houbara bustards was 165 x 10(6). There was no significant difference in fertility or in ability to hatch between the two subspecies. Overall, in 1992, mean fertility was 69.3% and 49.2% of eggs hatched. Females showed a median sperm storage duration of 10 days and a maximum sperm storage duration of 22 days. A positive correlation was found between fertility and quantity of spermatozoa inseminated (R = 0.99, P < 0.001). Sperm storage duration was related to the number of spermatozoa inseminated. The best results (85% fertile eggs) were obtained when more than 10(6) spermatozoa were inseminated between 3 and 6 days before laying. Analysis of hatching showed that embryo mortality increased when inseminations were performed more than 10 days before laying.

Animals↗