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J Roux

Publications and source records attributed to J Roux.

At least 37 records · Page 2Linked to original sources
PubMed1994

[Evolution of Schistosoma mansoni bilharziasis in Ampefy (Lake Itasy) from 1986 to 1993].

In 1976, 1983, 1986 to 1989 and 1993, the population of Ampefy, on the shores of lake Itasy, was invited to participate in an active detection programme of Schistosoma mansoni infection. An increase in the global prevalence was observed from 1976 (17.0%) to 1983 (40.0%). This prevalence level was then stabilized during the four years annual selective treatment (1986 to 1989) and the mean intensity of infection for positive patients fell from 393 eggs/g to 271 eggs/g and the proportion of severe infections, with a high risk of developing "hepatosplenic disease", fell from 8% to 4.2%. Selective treatment was interrupted from 1989 to 1993, during which time the global prevalence rose to 70.6% and mean intensity of infection to 594 eggs/g, with 22% of those examined classified as severely infested. This local control programme, associating active detection with annual treatment, seems effective in stabilizing prevalence and intensity of infection in spite of a regular arrival of infested, and never treated, immigrants. However, its impact throughout time is limited.

Adolescent↗
PubMed1994

[Dengue 1 epidemic in the Grand Comoro Island (Federal Islamic Republic of the Comores). March-May 1993].

An epidemic of dengue fever occurred in Grande Comore island from March to May 1993. Dengue 1 virus has been isolated. The epidemic did not affect the other islands of the archipelago. No compound clinical picture, in particular hemorrhagic, was reported. A random sampling survey conducted towards the end of April showed that 26% of the population aged 5 years old or more had IgM dengue antibodies. The epidemic concerned essentially individuals under 45 years of age. The number of inhabitants of Grande Comore affected by the outbreak can be estimated between 56,000 and 75,000. The results of the sero-epidemiological survey allowed to find the serological scar of two previous epidemics of dengue: the first one around 1948, which may correspond with dengue 1, the other one in 1984, probably with dengue 2.

Adolescent↗
PubMed1993

Demographic reductions and genetic bottlenecks in humans: minisatellite allele distributions in Oceania.

Polynesians have lower heterozygosities at minisatellite VNTR (Variable Number of Tandem Repeat) loci than have Melanesians; this has been taken as evidence of population-size bottlenecks during the colonisation of Polynesia. We have analysed the allelic distribution of several minisatellite loci in the population of Rapa, a Polynesian island that is known to have undergone a demographic reduction of approximately 95% since first contact with European explores 200 years ago, leaving a surviving population of 120. We found that the minisatellite diversity of this population does not differ significantly from that of other Polynesian populations, and appears consistent with the neutral expectation of diversity assuming the infinite alleles model. This suggests that the demographic crisis that Rapa underwent did not perturb the allele distribution to the extent that the tests used here could detect. Thus we cannot say that a demographic change of this magnitude constitutes a genetic bottleneck detectable at these loci. The reduced diversity seen in Polynesia must therefore be explained either by more severe bottlenecks as might be expected during colonisation, or else by other causes.

Alleles↗
PubMed1993

MK-801 and enantiomers: potential antidepressants or false positives in classical screening models?

In the present experiments, the noncompetitive NMDA antagonist 5-methyl-10,11-dihydroxy-5H-dibenzo(a,d)cyclo-hepten-5,10-imine (MK-801) and its (+) and (-) enantiomers were tested in classical screening models used to detect potential antidepressants. The drug and its enantiomers were active in the tail suspension test (TST). The racemate was also active in the forced swimming test (FST). The effects in these tests occurred, however, at doses with marked stimulant activity. Further investigations (reserpine, apomorphine, and yohimbine tests) could not confirm the suspected antidepressant activity. Other NMDA antagonists--2-amino-7-phosphonoheptanoic acid (AP7), kynurenic acid, and 1-glutamic acid diethylester (GDEE)--showed no activity in the TST. These findings throw doubt concerning the potential antidepressant activity of MK-801 and other NMDA antagonists.

Animals↗
PubMed1993

Parasite virulence factors during falciparum malaria: rosetting, cytoadherence, and modulation of cytoadherence by cytokines.

To determine virulence factors of isolates of Plasmodium falciparum and the potential role of cytokines in cerebral malaria, 46 Malagasy patients presenting with cerebral (n = 10), severe (n = 10), and uncomplicated (n = 26) malaria were enrolled in a study. The capacity of 21 of 46 P. falciparum isolates to form rosettes in vitro and to adhere to human umbilical vein endothelial cells (HUVECs) that express intercellular adhesion molecule-1 receptors and to C32 amelanotic melanoma cells that express mainly CD36 receptors was investigated together with the effects of tumor necrosis factor alpha (TNF-alpha), granulocyte macrophage-colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and IL-6 alone and in two-by-two combinations on the cytoadherence of infected erythrocytes to HUVECs. Plasma levels of these cytokines were also measured in the patients at admission. The percentage of rosette formation was higher for the isolates from patients with cerebral (n = 6; 19.5%) and severe (n = 6; 30.5%) malaria than for those from patients with uncomplicated malaria (n = 9; 5%) (P < 0.002). The cytoadherence properties of the isolates did not differ among the three groups whatever the target cell used, but adherence to melanoma cells was systematically higher than that to HUVECs. Adhesion to HUVECs was increased more after TNF-alpha stimulation than after GM-CSF, IL-3, or IL-6 stimulation (P < 0.01). Only the combination of TNF-alpha and IL-3 enhanced cytoadherence more than TNF-alpha used alone (P < 0.02). No difference in the modulation of cytoadherence by cytokines was found in relation to the severity of the disease. TNF-alpha and IL-6 levels in peripheral blood were higher in the patients with cerebral and severe malaria than in the patients with uncomplicated malaria (P < 0.005). Most of the patients' sera contained little or no IL-3 or GM-CSF. Our results challenge the role of intercellular adhesion molecule-1 as the principal receptor mediating the cytoadherence of P. falciparum-infected erythrocytes and contrast with data obtained in the murine model.

Adolescent↗
PubMed1993

[Epidemiological malaria surveillance in 3 villages of the Madagascar highlands].

Results of the epidemiological surveillance of falciparum malaria carried out since 1987 in three villages of the malagasy Highlands are reported. They clearly show the unsteady endemo-epidemic characteristic of the disease with highly variable transmission levels according to foci. At Manarintsoa, a south-western village 20km away from the Capital, the disease has now fully disappeared after the ravage of 1986. But it might reappear with new imported cases and by lack of antivectorial measures. Although Anopheles arabiensis had been rare and its aggressivity rate weak (0.91-2 infecting bites per year per man), surveillance is indispensable for the future. An Ankazobe and Mahavelona, two north-western localities respectively 100km and 65km away from Antananarivo, malaria is endemic with periodic outbreaks during rainy season. At Ankazobe, Anopheles funestus is the main vector maintaining endemic in this area while the role of Anopheles gambiae l.s. is only secondary. At Mahavelona, because of the weak presence of vectors, the treatment protocol by Quinimax has been applied in order to study transmission. This study obviously shows that contrary to set ideas in the Highlands, backward transmission is possible up to the first months of the austral winter (June-July). In these two last villages, adults have acquired some premunition.

Adolescent↗
PubMed1993

[Situation of endemic rabies in Madagascar].

The course of endemic rabies in Madagascar between 1982 and 1991 is related. Rabies has been raging over the whole island and dog is essentially affected, constituting the single vector of human rabies cases. The authors recall the main measures of struggle against rabies.

Adolescent↗
PubMed1993

[Aspects of Plasmodium falciparum sensitivity to chloroquine in Madagascar from 1982 to 1993].

According to pharmaco-sensitivity studies, about 20% of local Plasmodium falciparum strains showed a certain degree of resistance to chloroquine. No resistance of R3 type has never been observed. During this whole period, the decrease of sensitivity phenomenon remains stable. Because of its remarkable action on parasitemia and fever, chloroquine remains the best antimalaria in simple malarial attacks in madagascar.

Animals↗
PubMed1993

[Influenza surveillance in Tananarive during the year 1992].

The authors relate the 1992 results of influenza surveillance in Antananarivo. 24 influenza virus A (H3N2) strains were isolated from 467 pharyngeal swabs. The virus had been continually spreading from January to September, with a peak in July, along with some monthly sporadic isolations. The highest respiratory morbidity was observed in June and July. The collection processes of influenzal and respiratory morbidity statistics are also discussed in order to standardize data and to define the real impact of influenza and other acute affections of respiratory tracts on the population.

Acute Disease↗
PubMed1992

[Leprosy serology: current status and perspectives].

The different serological tests used for leprosy are firstly the methods for the detection of antibodies (anti-PGL1, 35kD, 36kD, LAM), and secondly, the tests to detect the PGL1 antigen from the serum or urine. The antibody detection tests have a good but insufficient specificity for the diagnosis of leprosy patients and their sensitivity is generally high for the multibacillary patients but low for the paucibacillary patients. Their positive predictive value for the diagnosis of patients in a population are very low: 2.1% for the anti-PGL1 ELISA when the prevalence is 1/1000. For the early diagnosis of patients and the follow up of high risk populations, these tests are not cost effective: the number of patients detected in these populations is 10 fold lower than in the general population and the relative risks for developing the disease are not different among seropositive and among seronegative groups. In treated multibacillary patients, the IgM anti-PGL1 level decreases in correlation with the decrease of the bacillary index. For the diagnosis of M. leprae infection in a population, there was no correlation between the anti-PGL1 seroprevalence and the prevalence of the disease. Concerning the PGL1 antigen detection tests, they are specific and sensitive for the diagnosis of multibacillary patients but they cannot be used in routine for technical reasons. In conclusion and to date, the usefulness of serological tests in a leprosy control programme is quite questionable.

Enzyme-Linked Immunosorbent Assay↗
PubMed1992

[Rift Valley fever in Madagascar in 1991. Sero-epidemiological studies in cattle].

Rift Valley fever (RVF) virus was detected for the first time in Madagascar in 1979, but without any impact on human and animal populations. However, in 1990 and 1991, several outbreaks with massive cattle abortions were described. Since that period, seroepidemiological surveys have been conducted on the East coast and in the highlands (outbreak areas), in the high cattle density regions, and in the national slaughter house in Antananarivo. A high RVF IgM antibody prevalence was detected in the outbreak areas during the epizootics. This IgM prevalence thereafter decreased and was followed by an IgG high prevalence in all tested regions. Hypotheses on the occurrence of the virus in Madagascar, outbreak origins and virus circulation on the island are discussed.

Animals↗
PubMed1992

[The plague: disease and vaccine?].

Plague has existed in Madagascar since 1896, with epidemic control achieved by GIRARD with an EV vaccine in 1937. Plague persists in Madagascar, however, due to the large animal reservoir. With a predilection for nodal tissues, Yersinia pestis is a virulent bacteria that is potent inducer of antibody synthesis. Immunity mechanisms stimulated by infection were studied: 1. In human by immunoenzymatic methods 2. In mice by seroprotection and vaccinating tests. Induced immunity for people in endemic and endemic-epidemic areas, is significant, affecting approximately 70% of these populations. In non endemic areas, immunity is found in only 33% of the population, perhaps this explains the persistence of epidemic? In all cases, this immunity is a quick onset (6 days), is persistent (> 2 years), and has demonstrable serious recognition of YOP (Yersinia Outer Proteins) by Western Blot method. Human antibodies were shown to be protective for mice. Animals vaccinated by YOP were protected equally well, when compared to animals infected with Yersinia pestis and subsequently treated with antibiotics. Finally, YOP aerosols were also shown to induce antibodies. In conclusion, plague is a vaccinatable bacterial disease and YOP can be used as an animal vaccine to permit plague control in the rat reservoir.

Aerosols↗
PubMed1992

[Cysticercosis in Madagascar: diagnostic and therapeutic improvement].

Human cysticercosis is linked to infection by the larval stage of Taenia solium: Cysticercus cellulosae and was identified in Madagascar since 1901. Neurocysticercosis constitute, when parasite is localized in cerebral vesicles, a disease with important neurologic symptoms: epilepsia, spasms... This disease would be diagnosed before parasite calcification and this diagnosis permit Praziquantel treatment indication, with good results in many cases. We have developed cysticercosis diagnosis permitting: stage definition of the disease: Elisa and Western Blot tests, therapeutic following by enzyme immunoassay capture of serum cysticercosis antigens. We have observed: disease prevalence of 18% proving high rate of circulating parasite, in the countries studies, significative variation of circulating antigens and/or antibodies, one month after one or two Praziquantel treatment, in 82% of 130 patients. This disease seems to be important in Madagascar in neurologic syndromes, but the solution of this problem would result in prophylactic and concerted actions by public health means.

Adolescent↗
PubMed1992

[Stability and chemosensitivity of Plasmodium falciparum to chloroquine in 1990 and 1991 in Ankazobe, a village in high plateau Madagascar].

The in vivo and in vitro response of Plasmodium falciparum to chloroquine was conducted in Ankazobe, a village located in the high plateau area. These studies confirmed the low level of chloroquine-resistance. The in vivo data indicate the absence of increase resistance during the 2 years study. Chloroquine is still the drug of choice for the treatment of malaria attack in this area.

Animals↗
PubMed1991

In vivo footprinting of rat TAT gene: dynamic interplay between the glucocorticoid receptor and a liver-specific factor.

HNF5, a liver-specific DNA-binding protein, interacts with DNA in a manner that allows DNAase I cleavage in the middle of its recognition sequence. Using this property we have identified in vivo HNF5 bound to its sites within two glucocorticoid-responsive units of the rat tyrosine aminotransferase (TAT) gene. One HNF5-binding site is also a glucocorticoid receptor-binding site; glucocorticoid-dependent HNF5 binding could be detected at this site even though it is incompatible with glucocorticoid receptor binding. HNF5 binds within 10 min of hormone addition, indicating that it participates in transcriptional activation. In the TAT gene glucocorticoid-dependent HNF5 binding occurs where there is glucocorticoid-dependent disruption of nucleosomal structure; constitutive binding occurs in constitutively disrupted regions. These results suggest a hit-and-run mechanism of transcriptional activation by glucocorticoid receptor: the activated receptor binds its target sequence, modifies local chromatin structure, then leaves its site accessible to another factor.

Animals↗
PubMed1991

Cell-type specific activity of two glucocorticoid responsive units of rat tyrosine aminotransferase gene is associated with multiple binding sites for C/EBP and a novel liver-specific nuclear factor.

The structures of two remote glucocorticoid responsive units (GRUs) that cooperatively interact to promote cell-type specific glucocorticoid induction of rat tyrosine aminotransferase gene expression have been analyzed. DNAase I footprinting and gel mobility shift analyses reveal a complex array of contiguous and overlapping sites for cell type-specific DNA binding proteins. Apart from the glucocorticoid receptor, two liver-specific nuclear factors possess multiple binding sites in each of these GRUs: C/EBP and a newly identified liver-specific factor: HNF5. C/EBP possesses four binding sites in each GRU; a DNA-binding protein with similar binding specificity has been identified in fibroblasts; this protein could be related to AP-3. HNF5 possesses two binding sites in one GRU and four in the other. There are also HNF5 binding sites in numerous regulatory regions of other liver-specific genes. The interaction of HNF5 with DNA gives a characteristic DNAase I footprint with hypersensitive sites in the middle of the recognition sequence. Some of the C/EBP and HNF5 binding sites overlap in a conserved arrangement.

Animals↗