PubMed Health⌕ Search

Biomedical subjects

D Che

Publications and source records attributed to D Che.

At least 19 recordsLinked to original sources
PubMed2006

[Principles of an outbreak investigation in public health practice].

An outbreak (or epidemic) is a higher number of cases of a given disease in a given population and time interval. A timely investigation has for aim to identify the source and vehicle of the outbreak and provides unique opportunities to better understand its occurrence and the role of contributing risk factors to implement the most appropriate measures to control it and prevent further recurrences. The investigation of an outbreak is based on a multidisciplinary approach (clinical, epidemiological, environmental, and microbiological) with a descriptive and analytical (hypothesis testing) phase. In this article, we describe the methodological approach of a field outbreak investigation illustrated by examples taken from our experience. The investigation includes the following steps: establishing the existence of the outbreak; defining the disease; finding cases; describing cases by time, place, and person characteristics; establishing a hypothesis related to the mode of occurrence; testing the hypotheses; conducting an environmental investigation; conducting a microbiological investigation; controlling the outbreak, preventing further occurrences, and writing an investigation report to share experience with the public health and scientific community. The investigation of an outbreak is an evolving process: information gathered or conclusions made at a given stage must be fully used for following steps. The social, institutional, and political background associated with outbreaks usually makes their investigation complex and should be taken into account. The earlier the outbreak is detected and investigated in close relation with public health authorities, the greater will be the potential preventive impact of control measures.

Adult↗
PubMed2006

An evaluation of data quality in a network for surveillance of Mycobacterium tuberculosis resistance to antituberculosis drugs in Ile-de-France region-2001-2002.

We evaluated the French Azay-Mycobacteria network for surveillance of Mycobacterium tuberculosis drug resistance by matching data with those collected through the mandatory notification (MNTB). Sensitivity of Azay was 96% by capture-recapture analysis. Cases reported to MNTB were more often smear-positive than non-reported cases. Concordance of data collected for common cases was excellent for a majority of variables (k > 0.79), excepted for tuberculosis site (k = 0.52). These results suggest a good quality of the network.

Antitubercular Agents↗
PubMed2005

Association between indicators of cattle density and incidence of paediatric haemolytic-uraemic syndrome (HUS) in children under 15 years of age in France between 1996 and 2001: an ecological study.

Over the past years Shiga-like toxin-producing Escherichia coli (STEC) O157:H7 emerged as an important cause of severe gastrointestinal illnesses and haemolytic-uraemic syndrome (HUS) with up to 10% of children infected with STEC developing HUS. We conducted a geographical ecological study using the district as the statistical unit. For each district, we estimated the incidence of HUS among children <15 years for the period 1996-2001 from national HUS surveillance data and data obtained on cattle density. We used multivariate Poisson regression to quantify the relation, adjusted for covariates, between paediatric HUS incidence and exposure to cattle. In univariate analysis, a positive association was observed between several cattle-density indicators and HUS incidence. In multivariate analysis, HUS paediatric incidence was associated with dairy cattle density and the ratio of calves to children <15 years (P<0.001). Our findings are consistent with previous studies in other countries and support the recommendation to limit exposure of children to dairy cattle and manure to reduce the risk of STEC infection.

Adolescent↗
PubMed2005

Incidence of tuberculous meningitis in France, 2000: a capture-recapture analysis.

OBJECTIVE: To estimate the incidence of culture-positive and culture-negative tuberculous meningitis (TBM) in France in 2000. METHODS: Capture-recapture method using two unrelated sources of data: the tuberculosis (TB) mandatory notification system (MNTB), recording patients treated by anti-tuberculosis drugs, and a survey by the National Reference Centre (NRC) for mycobacterial drug resistance, recording culture-positive TBM. RESULTS: Of 112 cases of TBM reported to the MNTB, 28 culture-positive and 34 culture-negative meningitis cases were validated (17 duplicates, 3 cases from outside France, 21 false notifications, and 9 lost records were excluded). The NRC recorded 31 culture-positive cases, including 21 known by the MNTB. When the capture-recapture method was applied to the reported culture-positive meningitis cases, the estimated number of meningitis cases was 41 and the incidence was 0.7 cases per million. Sensitivity was 75.6% for the NRC, 68.3% for the MNTB, and 92.7% for both systems together. When sensitivity of the MNTB for culture-positive cases was applied to culture-negative meningitis, the total estimated number of culture-negative meningitis cases was 50 and the incidence was 0.85 cases per million. CONCLUSION: TBM is underestimated in France. Capture-recapture analysis using different sources to better estimate its incidence is of great interest.

Adult↗
PubMed2004

[Epidemiology of tuberculosis in Ile-de-France in 2001].

INTRODUCTION: The incidence of tuberculosis in France is stable at around 10 per 100,000 per year since 1997. However in the Ile-de-France (which includes Paris and its suburbs) high population density, social deprivation and large numbers of immigrants result in the region providing more than half of the total number of cases notified in France. METHODS: Retrospective analysis using data from the mandatory notification forms of patients diagnosed in 2001. RESULTS: The incidence of tuberculosis in 2001 was 27.2 cases per 100,000 in the Ile-de-France region and 48.4 per 100,000 in the Paris area. The incidence was particularly high amongst young immigrants, especially those from Sub-Saharian countries. Pulmonary tuberculosis was the most commonly observed disease form (72% of cases). HIV infection was documented in 7.5% of subjects. Local tuberculosis control services were asked to intervene in only 30% of overall cases, and in only 50% of pulmonary cases living in crowded housing. CONCLUSION: More resource is needed for the surveillance of tuberculosis and the implementation of public health initiatives in the Ile-de-France to strengthen the fight against tuberculosis.

Adolescent↗
PubMed2004

Clusters of travel associated legionnaires' disease in France, September 2001- August 2003.

Clusters of travel associated legionnaires' disease warrant urgent attention, and are detected by the French national surveillance system and the European network EWGLINET. Between September 2001 and August 2003, 37 clusters were identified in French tourist accommodation: 27 hotels and 10 campsites. The number of clinical cases per cluster was as follows: 30 clusters of 2 cases (81%), 6 clusters of 3 cases (16%) and one cluster of 4 cases (3%), a total of 82 cases. The local health authorities performed environmental investigations for 36 of the 37 clusters. Among the 36 clusters investigated, water samples were collected for 35. At 16 (46%) sites, Legionella pneumophila was found at a level of more than 103 cfu/litre. In all of the accommodation where risk assessment was found to be inadequate- control measures were implemented immediately. Six hotels were closed immediately following cluster alerts. Comparison of clinical and environmental isolates by pulsed field gel electrophoresis (PFGE) was possible in 3 clusters and identical genomic profiles of the isolates were found in all. During this two year period of surveillance, we found that on many sites there has been a risk of exposure to Legionella. This reinforces the importance of the European surveillance network and the timely notifications of all the cases to EWGLINET.

Disease Notification↗
PubMed2003

Sporadic cases of community acquired legionnaires' disease: an ecological study to identify new sources of contamination.

STUDY OBJECTIVE: To explore the relation between incidence of sporadic and community acquired legionnaires' disease and exposure to potentially contaminated industrial aerosols. DESIGN: Geographical ecological approach using the postcode as the statistical unit. A multivariate Poisson regression model was used to model the relation between exposure to industrial aerosols and legionnaires' disease. SETTING: Metropolitan France. MAIN RESULTS: More than 1000 sources of industrial exposure (aerosol and plume of smoke) were identified in 42 French departments. After adjusting for confounding factors, there was a statistically increased incidence of legionnaires' disease in postcodes with plume of smoke in comparison with postcodes without (RR=1.45, 95% CI=1.12 to 1.87), and in postcodes with more than one aerosol in comparison with postcodes without (RR=1.37, 95% CI=1.04 to 1.79). CONCLUSION: These findings highlight that any industrial systems generating water aerosols should be regarded as potential sources of contamination for legionnaires' disease.

Aerosols↗
PubMed2002

[Research activities of interns in pharmacy].

During their hospital internship, French pharmacists have many opportunities to participate in research activities, especially in post-doctoral work (DEA). We conducted a national survey among pharmacy residents and interns to ascertain their motivations before completing their diploma. Many (about 50%) considered their post-doctorate work as an initiation before starting their scientific profession. Other motivations were also noted. This study provides data for future comparisons.

Attitude of Health Personnel↗
PubMed2002

[Genetic polymorphism of pyruvate dehydrogenase kinase 4 (PDK4), paraoxonase 2 (PON2), and fatty acid binding protein 2 (FABP2) in the NIDDM population of Senegal].

We reported a study about three candidate genes which may be involved in non-insulin dependent diabetes mellitus (NIDDM): Pyruvate Dehydrogenase Kinase 4 (PDK4), Paraoxonase 2 (PON2) and Fatty Acid Binding Protein 2 (FABP2). The reported mutation in the three candidate genes were tested for 179 black subjects from Dakar (Sénégal) by PCR-RFLP techniques. There was no significant difference between both control and NIDDM subjects. The genotype frequency in the senegalese population was quite similar as compared to reported frequency in white populations excepted for PDK4 polymorphism. These results suggest that none of these gene variants is a major NIDDM predisposing locus for the negroid population of Senegal.

Adolescent↗
PubMed2001

A simple resolution procedure using the Staudinger reaction for the preparation of P-stereogenic phosphine oxides.

The resolution of a variety of (+/-)-P-stereogenic phosphines is achieved by exploiting the Staudinger reaction of a (+/-)-phosphine with enantiopure (1S,2R)-O-(tert-butyldimethylsilyl)isobornyl-10-sulfonyl azide. The resulting mixtures of diastereomeric phosphinimines are generally separable by fractional crystallization or flash chromatography. Subsequent acid-catalyzed hydrolysis provides the corresponding optically pure phosphine oxides in high yields.

Journal Article↗
PubMed2001

exo-2-(Pyridazin-4-yl)-7-azabicyclo[2.2.1]heptanes: syntheses and nicotinic acetylcholine receptor agonist activity of potent pyridazine analogues of (+/-)-epibatidine.

A new strategy for the straightforward synthesis of novel racemic epibatidine analogues is presented, in which the 2-chloropyridinyl moiety of epibatidine is bioisosterically replaced by differently substituted pyridazine rings. A key step of the new syntheses is the inverse type Diels-Alder reaction of the electron-rich enol ether 13 with the electron-deficient diazadiene systems of the 1,2,4, 5-tetrazines 14a-d to yield the novel pyridazine analogues of (+/-)-epibatidine 18, 19, 22, and 24. In addition preparation of the N-substituted derivatives, such as 26 and 28, is described. The structures of the novel epibatidine analogues were assigned on the basis of spectral data, that of compound 24 being additionally verified by X-ray crystallography exhibiting two racemic solid-state conformations in the crystal lattice and representing the first X-ray structure of an unprotected 7-azabicyclo[2.2.1]heptane moiety. The nAChR agonist activity of the racemic compounds 18, 19, 22, 24, and 28 was assayed in vitro by whole-cell current recordings from Xenopus oocytes expressing different recombinant nicotinic receptors from the rat. Among the compounds synthesized and tested, the pyridazine analogue 24 of (+/-)-epibatidine and its N-methyl derivative 28 were found to be the most active ones retaining much of the potency of natural epibatidine but with a substantially improved selectivity ratio between the alpha4beta2 and alpha3beta4 subtypes.

Animals↗
PubMed2001

Effects of DDPH on HECCM-induced proliferation and immunophenotypes of the pulmonary vascular pericytes.

In order to study the effects of 1-(2, 6-dimethylphenoxy)-2-(3, 4-dimethoxyphenylethylamino) propane hydrochloride (DDPH) on proliferation and immunophenotypes of newborn rat pulmonary vascular pericytes induced by hypoxic endothelial cell conditioned medium (HECCM) from porcine pulmonary arteries, the cultured pericytes were divided into 4 groups according to the endothelial cell conditioned medium (ECCM) used: normoxic ECCM (NECCM) group, NECCM + DDPH group, HECCM group and HECCM + DDPH group. Cell culture, immunocytochemical staining, image analysis and flow cytometric method were used to investigate the effects of HECCM and DDPH on the expression of alpha-smooth muscle actin (alpha-SM-Actin) antigen, CD34 antigen, S-100 antigen and proliferating cell nuclear antigen (PCNA) and cell cycle in pericytes. The results showed that the alpha-SM-Actin antigen in the pericytes in HECCM group was stronger positively expressed than in the other three groups, but CD34 antigen and S-100 antigen were negatively expressed. The expression of alpha-SM-Actin antigen, CD34 antigen and S-100 antigen was positive in the groups of NECCM, NECCM + DDPH and HECCM + DDPH; The expression of alpha-SM-Actin and PCNA in HECCM group was 1.32 times (P < 0.01) and 1.24 times (P < 0.05) that in NECCM group, 1.30 times (P < 0.01) and 1.21 times (P < 0.05) that in HECCM + DDPH group, respectively. The percentage of the cells in the GO-G1 phase in the HECCM group was lower by 11.7% and 9.1%, in S phase higher by 5.6% and 4.2%, in G2-M phase higher by 6.1% and 4.9% than in the groups of NECCM, HECCM + DDPH, respectively. The inhibitory rate of DDPH on the increased alpha-SM-Actin and PCNA syntheses in pericytes induced by HECCM were 23.4% and 17.1% respectively. The inhibitory rate on the increased pericytes from GO-G1 phase to S phase was 8.3%. These results suggest that DDPH can directly inhibit pericytes from proliferation and immunophenotypical transformation of smooth muscle-like cells induced by HECCM.

Animals↗
PubMed2001

17beta-estradiol inhibits soluble guanylate cyclase activity through a protein tyrosine phosphatase in PC12 cells.

Besides its involvement in reproductive functions, estrogen protects against the development of cardiovascular diseases. The guanylate cyclase/cGMP system is known to exert potent effects on the regulation of blood pressure and electrolyte balance. We examined whether 17beta-estradiol can affect soluble guanylate cyclase in PC12 cells. The results indicate that 17beta-estradiol decreases cGMP levels in PC12 cells. 17beta-Estradiol decreases sodium nitroprusside (SNP)-stimulated, but not atrial natriuretic factor-stimulated cGMP formation in PC12 cells, indicating that 17beta-estradiol decreases cGMP levels by inhibiting the activity of soluble guanylate cyclase. 17beta-Estradiol also stimulates protein tyrosine phosphatase activities in PC12 cells and dephosphorylates at least three proteins. Addition of sodium vanadate, a protein tyrosine phosphatase inhibitor, blocks the inhibitory effects of 17beta-estradiol on soluble guanylate cyclase activity in PC12 cells. Furthermore, transfection of SHP-1, a protein tyrosine phosphatase, into PC12 cells inhibits both basal and SNP-stimulated guanylate cyclase activity. Amino acid analysis also reveals that the 70-kDa subunit of soluble guanylate cyclase contains the SHP-1 substrate consensus sequence. These results suggest that 17beta-estradiol inhibits soluble guanylate cyclase activity through SHP-1.

Animals↗
PubMed2001

Novel surface and multicolor charge coupled device-based fluorescent imaging system for DNA microarrays.

We report a novel support, concomitant attachment chemistry, and a fluorescent imaging system for DNA microarrays. The support consists of soda lime glass coated with a layer of chromium, which eliminates any autofluorescence from the underlying glass substrate and reduces nonspecific probe binding. Attachment of DNA fragments exceeding 300 nucleotides in length is achieved without chemical modifications of either the chrome surface or the DNA itself. The charge coupled device (CCD)-based imaging system employs a 175 W xenon arc lamp as the light source, allowing the use of many different fluorophors. A 14 mm x 9 mm sample area is imaged with a single exposure, which takes between 5 and 20 s for each color plane in typical genomic comparative genomic hybridization type assays. The spatial resolution is limited only by the pixel size of the CCD chip (9 microm). The oblique illumination geometry combined with effective background reduction afforded by the chromium surface enables the system to achieve a detection limit of <5 x 10(7) fluorophors/cm(2) with 10 s integration. In a model system with arrayed lambda DNA targets a dose response was observed over four orders of magnitude in response to hybridizations with increasing amounts of the fluorescent labeled lambda probe.

Escherichia coli↗
PubMed2001

Antioxidants, vitamin C and dithiothreitol, activate membrane-bound guanylate cyclase in PC12 cells.

Antioxidants and antioxidant enzymes are known to protect against cell death induced by reactive oxygen species. However, apart from directly quenching free radicals, little is known about the effect of antioxidants on hormone-activated second messenger systems. We previously found that antioxidants such as 17-beta estradiol and resveratrol activate membrane-bound guanylate cyclase GC-A, the receptor for atrial natriuretic factor (ANF), in PC12 cells. It is possible that other antioxidants may also activate membrane-bound guanylate cyclase GC-A. The aim of this study was to determine if dithiothreitol (DTT), vitamin C, and vitamin E activate membrane-bound guanylate cyclase GC-A in PC12 cells. The results showed that both DTT and vitamin C increased cGMP levels in PC12 cells, whereas vitamin E had no effect. DTT and vitamin C inhibited membrane-bound guanylate cyclase activity stimulated by ANF in PC12 cells. In contrast, DTT and vitamin C had no effect on soluble guanylate cyclase activity stimulated by substance P. Furthermore, NO synthase inhibitors L-NAME and aminoguanidine did not affect DTT- and vitamin C-stimulated guanylate cyclase activity. The results indicate that DTT and vitamin C, but not vitamin E, activate membrane-bound guanylate cyclase GC-A in PC12 cells.

Animals↗