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P Buchy

Publications and source records attributed to P Buchy.

6 recordsLinked to original sources
PubMed2006

Natural variation can significantly alter the sensitivity of influenza A (H5N1) viruses to oseltamivir.

Geographic spread of highly pathogenic avian H5N1 influenza viruses may give rise to an influenza pandemic. During the first months of a pandemic, control measures would rely mainly on antiviral drugs, such as the neuraminidase (NA) inhibitors oseltamivir and zanamivir. In this study, we compare the sensitivities to oseltamivir of the NAs of several highly pathogenic H5N1 viruses isolated in Asia from 1997 to 2005. The corresponding 50% inhibitory concentrations were determined using a standard in vitro NA inhibition assay. The K(m) for the substrate and the affinity for the inhibitor (K(i)) of NA were determined for a 1997 and a 2005 virus, using an NA inhibition assay on cells transiently expressing the viral enzyme. Our data show that the sensitivities of the NAs of H5N1 viruses isolated in 2004 and 2005 to oseltamivir are about 10-fold higher than those of earlier H5N1 viruses or currently circulating H1N1 viruses. Three-dimensional modeling of the N1 protein predicted that Glu248Gly and Tyr252His changes could account for increased sensitivity. Our data indicate that genetic variation in the absence of any drug-selective pressure may result in significant variations in sensitivity to anti-NA drugs. Although the clinical relevance of a 10-fold increase in the sensitivity of NA to oseltamivir needs to be investigated further, the possibility that sensitivity to anti-NA drugs could increase (or possibly decrease) significantly, even in the absence of treatment, underscores the need for continuous evaluation of the impact of genetic drift on this parameter, especially for influenza viruses with pandemic potential.

Antiviral Agents↗
PubMed2004

[Prevalence of hepatitis A, B, C and E virus markers among patients with elevated levels of Alanine aminotransferase and Aspartate aminotransferase in Phnom Penh (Cambodia) and Nha Trang (Central Vietnam)].

In order to describe the respective part of viral hepatitis in liver diseases observed in Cambodia and Vietnam, ninety consecutive patients with Aspartate aminotransferase (AST) and Alanine aminotransferase (ALT) > or = 100 Ul/l were tested for hepatitis A, B, C and E markers in Phnom Penh and Nha Trang. The markers were IgM antibodies to hepatitis A virus (anti-HAV IgM), hepatitis B surface antigen (HBsAg), antibodies to hepatitis C virus (anti-HCVAb) and IgG antibodies to hepatitis E virus (anti-HEV IgG). Recruited patients were predominantly adults and male (sex ratio 76%). Among these patients, 81% were tested positive to at least one marker in Nha Trang and 79% in Phnom Penh. In Nha Trang, HBsAg was more frequent (73%) than anti-HCV Ab (9%) while in Phnom Penh both markers were closely similar (HBsAg: 41%, anti-HCV Ab: 39%). In both population samples, HBsAg was more prevalent among young people whereas anti-HCV Ab were only detected in adults. No case of acute HAV infection was diagnosed in Nha Trang while anti-HAV IgM were detected in 20% of Cambodian patients. Anti-HEV IgG were infrequent (2% in Nha Trang, 5.5% in Phnom Penh). Only one case was notified, a male Vietnamese patient probably suffering from acute hepatitis E. More studies would be useful to improve the control measures against viral hepatitis in the public health programs.

Adolescent↗
PubMed2003

[Intestinal parasitoses in the Mahajanga region, west coast of Madagascar].

A study on human intestinal parasites was carried out from November 1996 until January 1997, in Mahajanga's hospital, on the western coast of Madagascar. We collected the faeces from 401 patients and the sera from 112 of them. Faecal examination using direct examination and MIF method revealed that 67.6% of the stools contained at least one parasite. The frequency of the protozoa was high (47.7%). The prevalence of the nematodosis reached 23.4%. Hymenolepis nana, Taenia saginata or solium and Schistosoma mansoni were less frequent (respectively 2.5%, 0.75% and 3.7%). More than 50% of the sera contained antibodies anti-Ascaris lumbricoides and anti-Strongyloides stercoralis. Serology by IFI using Schistosoma antigen was positive in 15.2% of the cases. The serological and microscopical exams showed that Entamoeba histolytica was present in this region and that amoebiasis should be considered as one of the etiologies of diarrhoea. The study pointed out also the frequency of the transmitted fecal infections. Preventive measures as water distribution, sanitary installations, hygiene education should be implemented.

Adolescent↗
PubMed2003

[Serological study of toxoplasmosis in Vietnam in a population of drug users (Ho Chi Minh city) and pregnant women (Nha Trang)].

Toxoplasmosis is a neglected disease in Vietnam particularly in populations with a high risk of developing complications. The seroprevalence of Toxoplasma gondii was calculated by testing blood samples for Toxoplasma specifically immunoglobulin G and immunoglobulin M on 300 intravascular drug users and on 300 pregnant women. Among intravascular drug users, the seroprevalence of IgG and IgM was 7.7% and 0.08%, respectively. In pregnant women the prevalence of anti-toxoplasmosis IgG and IgM was respectively 11.2% and 0%. 0.28% of all estimated pregnancies in Vietnam are affected with toxoplasmosis, i.e. around 4800 pregnancies per year. In conclusion, a screening of Toxoplasma infections should be recommended in HIV/AIDS patients.

Adolescent↗
PubMed1997

Field evaluation of an immunoglobulin G anti-F1 enzyme-linked immunosorbent assay for serodiagnosis of human plague in Madagascar.

Bacteriological isolation of Yersinia pestis is the reference test for confirming plague infection, but recovery of the pathogen from human samples is usually very poor. When the etiology of the disease cannot be bacteriologically confirmed, it may be useful to possess alternative tests such as detection of specific circulating antibodies to help guide the diagnosis. In the present study, the immunoglobulin G (IgG) anti-F1 enzyme-linked immunosorbent assay (ELISA) has been applied to various human sera to evaluate its large-scale applicability in the high-endemicity plague foci of Madagascar. The sensitivity of the test was found to be 91.4%, and its specificity was 98.5%. The positive and negative predictive values were 96 and 96.6%, respectively. Seroconversion was observed on day 7 after onset of the disease. Patients with a positive ELISA result could be separated into high (82%) and low (18%) IgG anti-F1 responders. Cross-reactions with eight other infectious diseases prevalent in Madagascar were scarce and were found in 1 of 27 Mycobacterium tuberculosis-, 3 of 34 Schistosoma haematobium-, and 1 of 41 Salmonella-infected patients. Finally, the efficiency of the IgG anti-F1 ELISA was evaluated during the Mahajanga, Madagascar, plague outbreak of 1995. When the number of ELISA-positive patients was added to the number of bacteriologically confirmed and probable cases, the number of positive patients was increased by 35%. In conclusion, although it does not replace bacteriology, IgG anti-F1 ELISA is a useful and powerful tool for retrospective diagnosis and epidemiological surveillance of plague outbreaks.

Antibodies, Bacterial↗