Biomedical subjects

V Robert

Publications and source records attributed to V Robert.

At least 19 recordsLinked to original sources

PubMed2006

[Treatment by plasmapheresis of a thrombotic thrombocytopenic purpura associated to a Still's disease: a case report].

We report the seventh published case of thrombotic thrombocytopenic purpura (TTP) associated to a Still's disease. We confirmed the secondary character of TTP using the measurement of ADAMTS 13 protease. Because of clinical and biological improvement, daily plasmapheresis was stopped after eight days of ICU treatment. Unfortunately, early (24 hours) relapse occurred resulting in daily plasmapheresis resumption for 11 more days. Main therapeutic goals and aggressive treatment duration of PTT associated with a Still's disease remain to be determined.

ADAM Proteins↗

PubMed2006

First report of Litomosa spp. (Nematoda: Filarioidea) from Malagasy bats; review of the genus and relationships between species.

The presence of the filarial genus Litomosa in Malagasy bats is demonstrated by the finding of L. goodmani n. sp. from Miniopterus gleni and Litomosa sp. (male unknown) from M. manavi, both in the Special Reserve of Ankarana. These materials are compared to the 22 Litomosa species, including two Indian species originally placed in the genus Litomosoides, L. fotedari (Gupta and Trivedi, 1989) n. comb. and L. tewarii (Gupta and Trivedi, 1989) n. comb., and the new taxon L. seurati n. sp. (= L. beaucournui Bain, 1966 pro parte), type-host Rhinolophus ferrum-equinum, Algeria, distinguished by the narrow area rugosa and the female caudal extremity with two conspicuous points, instead of several small ones. The Malagasy material belongs to a group of species close to the type, L. filaria, which have a male area rugosa composed of cuticular bosses and microfilariae folded within the sheath, and which are parasitic in Vespertilionidae, Hipposideridae and Rhinolophidae from Africa and Europe. The two Malagasy species resemble L. seurati n. sp., L. beshkovi Jancev, 1971, L. chiropterum Ortlepp, 1932, L. adami Petit, 1980 and L. ottavianii Lagrange et Bettini, 1948, with the enlarged third segment of the buccal capsule. L. goodmani n. sp. is distinct with its small size and female caudal extremity with a single point, which is suppressed in old mature worms; the females of Litomosa sp. have two conical points. Relationships among Litomosa species appear to be dependent upon both the chiropteran host groups and the geographical region.

Animals↗

PubMed2006

Molecular characterization of the malaria vector Anopheles gambiae s.s. in Madagascar.

Anopheles gambiae s.s. Giles (Diptera: Culicidae), the primary African malaria vector, has been characterized at the subspecies level in Madagascar, where only the molecular form S and haplotype gIA occur. The haplotype gIC proposed by other authors was not observed amongst the 35 mosquito genomes sequenced. These S/gIA characteristics are also found on the Comoros archipelago and in continental Africa.

Animals↗

PubMed2006

[Evidence of an urban, local transmission of malaria in Antananarivo, Madagascar].

Madagascar presents a large heterogeneity in terms of climate and altitude, which explains the uneven spread of malaria throughout the island. The capital, Antananarivo, counts more than one million inhabitants, altitude between 1250 and 1470 m, in an area where the transmission is low but malaria may cause deadly epidemic outbreaks. Numerous malaria cases are reported, without biological confirmation, and reliable data about urban malaria transmission are lacking. The " Institut Pasteur de Madagascar" together with the Malagasy Ministry of Health performed in 2003 a study about malaria transmission in Antananarivo. A prevalence survey of malaria among fever syndromes, with data collected from 43 urban dispensaries, showed that confirmed malaria cases represented only 2% of the total fever cases (15 cases out of 779 fever syndromes). The vast majority was imported from costal areas (13 cases out of 15), where malaria is hyperendemic. However, a local urban transmission was found for two patients and five other subjects identified during a proximity survey. Vectors A. arabiensis and A. funestus were found inside the patient houses, located in close proximity of flooded rice fields. Genetic analysis of P. falciparum strains allowed to distinguish three genotypes, aggregated by house. The analysis of parasite genome polymorphism proves here its validity for epidemic surveys in areas where malaria is unstable, with no premunition in the local urban population.

Adolescent↗

PubMed2005

[Phlebotomine sandflies from Madagascar (Diptera: Psychodidae). IV--Description of Sergentomyia (Rondanomyia) goodmani n. sp. Reinstatement of the subgenus Rondanomyia Theodor].

This work is the fourth related to species recently described from Madagascar. The authors describe Sergentomyia goodmani on females and males. The female has tubular spermathecae with internal spines. It has an aspect, in Canada balsam, of transversally striped spermatheca, without being completely segmented. The spermathecal ducts share a proximal common part. The pharynx is narrow. The cibarial armature is comb-like. Based on these characters, the authors consider that S. goodmani belongs to the subgenus Rondanomyia. They reinstate this subgenus and consider Neophlebotomus sensu Lewis, 1977 as invalid. Considering Grassomyia as a genus, this is the first record of Sergentomyia in Madagascar.

Animals↗

PubMed2005

Taxonomy and phylogeny of the ascomycetous yeast genus Zygoascus, with proposal of Zygoascus meyerae sp. nov. and related anamorphic varieties.

Physiological characters, mating compatibility, PCR-RAPD fingerprints, mol% G + C content, DNA-DNA relatedness, and large-subunit and internal transcribed spacer rRNA gene sequences of strains assigned to the genus Zygoascus were re-examined. On the basis of those data, and after phylogenetic analyses, an emendation of Zygoascus hellenicus (type material is a cross of CBS 6736(T) x CBS 5839(T)) is proposed, comprising two novel anamorphic varieties, Candida steatolytica var. steatolytica (CBS 6736(T)) and C. steatolytica var. inositophila (CBS 5839(T)). A novel teleomorphic species, Zygoascus meyerae sp. nov. (type material is a cross of CBS 4099(T) x CBS 7521(T)) is described, together with two novel anamorphic varieties corresponding to it, Candida hellenica var. hellenica (CBS 4099(T)) and C. hellenica var. acidophila (CBS 7115(T)).

Base Composition↗

PubMed2004

[Phlebotomus from Madagascar (Diptera: Psychodidae). II--Description of the female Phlebotomus (Anaphlebotomus) fertei Depaquit, Léger & Robert, 2002; description of the male and new data for the female Phlebotomus (Anaphlebotomus) berentiensis (Léger & Rodhain, 1978) comb. nov].

The female of Phlebotomus (Anaphlebotomus) fertei Depaquit, Léger & Robert, 2002 is described from Madagascar. The spermathecae have separated ducts, a body with an enlarged-sclerified dilatation and a deriviated large bladder with thin walls and long head. P. fertei female has the following characters: long antennal segments, pharyngeal armature with small teeth and cibarium with 15 to 30 denticles, and very long legs. Its remarkable spermatheca is closely related to that of P. berentiensis. The status of P. (Anaphlebotomus) berentiensis (Léger & Rodhain, 1978) is revised into this paper. The female is redescribed and the male is described for the first time. The latter has an unusual antennal formula (2/III-XII), a cibarium with four teeth and about 30 denticles, no tuft of setae on the coxite, four spines on the style, including a very long proximal one. Males and females were linked to each other based on morphological and molecular characteristics (second internal transcribed spacer of the ribosomal DNA and ND4 gene of the mitochondrial DNA). The inclusion of these taxa into the subgenus Anaphlebotomus Theodor, 1948 is exclusively based on male characters as listed by Theodor (style with four spines, no basal lobe on the coxite, paramere with two or three branches). The very heterogeneous characters of the females do not allow their use for the definition of this subgenus, which is probably not homogeneous.

Animals↗

PubMed2004

[Phlebotomus from Madagascar (Diptera: Psychodidae). III--Description of Phlebotomus (Anaphlebotomus) fontenillei n. sp].

The male of Phlebotomus (Anaphlebotomus) fontenillei n. sp. is described from Namoroka area (Madagascar). Its belongs to the subgenus Anaphlebotomus: style with four spines, coxite without basal process and paramere with two branches. It shares with P. berentiensis an original and exclusive antennal formula: 2/III-XII which distinguishes them from P. fertei. P. fontenillei n. sp. differs mainly from P. berentiensis by about 40 setae in tuft on the ventral face of the coxite, the length of the genital ducts and the position of the spines on the style. Sequence of the second internal transcribed spacer (ITS2) of the ribosomal DNA (rDNA) is very informative: the male of P. fontenillei n. sp. cannot be linked to the female of P. huberti (male unknown) regarding the size of amplified DNA fragment (459 bp versus 600 respectively) and the high degree of variability. There are few differences (10 mutations) between the sequences of P. fontenillei n. sp. and P. berentiensis which are closely related species.

Animals↗

PubMed2004

Recurrent isolation of an uncommon yeast, Candida pararugosa, from a sarcoma patient.

A yeast was repeatedly isolated from the saliva of a sarcoma patient. A relatively uncommon species, Candida maris, was identified based on the API 20C profile. The yeast species most frequently obtained from the patient's mother and from clinic staff was Candida albicans. A comparison of the yeast obtained from the patient with the type strain of C. maris strongly suggested that the former was not representative of C. maris. Analysis of partial ribosomal DNA sequences of the patient strain and from the type strain of C. maris showed that the two are phylogenetically not closely related. The patient strain was very close to Candida pararugosa, a relatively uncommon asporogenous yeast. DNA reassociation studies among C. pararugosa and patient isolates showed that they were conspecific. We could not determine the source of the yeast infection. This case will alert hospital staff to be aware of the possibility of unexpected environmental microorganisms as causes of infections, colonizations and persistent environmental contamination events in immunocompromised patients.

Animals↗

PubMed2004

Efficacy of artemether-lumefantrine treatment in patients with acute uncomplicated Falciparum malaria in Mayotte, a French collectivity of the Comoros Archipelago.

Mayotte is a French island located in the Comoros archipelago in the Indian Ocean. Due to the high level of resistance to chloroquine and sulfadoxine-pyrimethamine in this area, new therapeutic strategies are required. The aim was to assess and to document the efficacy of artemether-lumefantrine (AL) combination in four oral dosages. The follow-up was carried out during 21 days to monitor the antimalarial drug efficacy in an open trial in April-May, 2002. Results were obtained from 51 patients, aged from three to 46 years (12% less than five years). No case of therapeutic failure was observed. At day 2 after treatment, all the patients were apyretic and none of them had parasitaemia until day 21. This first therapeutic trial of the AL combination in the Indian Ocean sub-region shows that this association is safe, effective and rapid. AL should be an alternative treatment of uncomplicated malaria attacks in Comoros Archipelago, and will be of help to manage imported chloroquine-resistant falciparum malaria strains in Madagascar.

Administration, Oral↗

PubMed2003

Sex ratio of Plasmodium falciparum gametocytes in inhabitants of Dielmo, Senegal.

An epidemiological survey was conducted during a 4-month period of intense malaria transmission in Dielmo, a holoendemic Senegalese village. Two thick blood smears per inhabitant were collected weekly. The sex ratio of Plasmodium falciparum gametocytes (gamete precursors) was studied in 50 gametocyte carriers. All age classes were represented (mean 19.7 years; range: 2 months-75 years); 42 (84%) of them did not receive antimalarial treatment. Overall 668 thick smears were examined until 100 gametocytes had been counted or for 40 min. A total of 11204 gametocytes were observed with a mean sex ratio of 0.346 (95% CI 0.317-0.374), i.e. 2.89 females per 1 male. Among the 284 thick smears in which at least 10 gametocytes were observed, the mean percentage of male gametocytes was 27.8%, with a range of 0-82%. Great variability was observed between gametocyte carriers and also between thick smears from the same gametocyte carrier. A multivariate analysis was performed which highlighted the fact that only 2 variables had a significant effect on the sex ratio. Anaemia was associated with an increased percentage of males (Prevalence Rate Ratio [PPR] of male gametocytes was multiplied by 1.65 if haematocrit rate < 32%) and a wave of gametocytes was associated with an increased percentage of female gametocytes (PRR was multiplied by 0.48 during the peak of gametocytaemia and for the 2 weeks following this peak). The variables without significant effect on sex ratio were: age, sex, clinical status and sickle cell trait status of the gametocyte carrier, density of asexual parasites, quinine treatment, and gametocyte density (when taking account of its waves). These results are discussed in regard of possible differential production, mortality or sequestration of one gametocyte sex and selective advantages for the transmission of parasites.

Aged↗

PubMed2003

Togetherness among Plasmodium falciparum gametocytes: interpretation through simulation and consequences for malaria transmission.

Previous experimental gametocyte infections of Anopheles arabiensis on 3 volunteers naturally infected with Plasmodium falciparum were conducted in Senegal. They showed that gametocyte counts in the mosquitoes are, like macroparasite intakes, heterogeneous (overdispersed). They followed a negative binomial distribution, the overdispersion coefficient seeming constant (k = 3.1). To try to explain this heterogeneity, we used an individual-based model (IBM), simulating the behaviour of gametocytes in the human blood circulation and their ingestion by mosquitoes. The hypothesis was that there exists a clustering of the gametocytes in the capillaries. From a series of simulations, in the case of clustering the following results were obtained: (i) the distribution of the gametocytes ingested by the mosquitoes followed a negative binomial, (ii) the k coefficient significantly increased with the density of circulating gametocytes. To validate this model result, 2 more experiments were conducted in Cameroon. Pooled experiments showed a distinct density dependency of the k-values. The simulation results and the experimental results were thus in agreement and suggested that an aggregation process at the microscopic level might produce the density-dependent overdispersion at the macroscopic level. Simulations also suggested that the clustering of gametocytes might facilitate fertilization of gametes.

Aedes↗

PubMed2003

[Molecular characterization of mosquitoes of the Anopheles gambiae complex from Mayotte and Great Comoro].

The mosquitoes of the Anopheles gambiae complex have been characterised at specific and sub-specific levels in two islands of the Comoros archipelago: the island of Mayotte (French departmental collectivity) and the island of Grande Comore (Comoros Union). Results are similar in the two islands and are presented together. The species An. gambiae s.s. was observed alone (determination performed on 149 specimens by PCR product of IGS of rDNA). The molecular form observed alone was S, and corresponds in this geographic area to the chromosomal form Savanna (determination performed on 123 specimens by another PCR product of IGS of rDNA). The haplotype IB was observed alone (determination performed on ten specimens, by sequencing the ITS of rDNA, with special attention at the position 871 of ITS), as previously observed by other authors in East Africa. Finally, in Mayotte and Grande Comore the An. gambiae complex is only composed by An. gambiae s.s. from the molecular form S/type IB.

Animals↗

PubMed2003

Prostaglandin-independent effects of aspirin on cell cycle and putrescine synthesis in human colon carcinoma cells.

Aspirin consumption has been reported to be able to reduce colorectal cancer risk in humans and in animal models of colon carcinogenesis. Although the mechanism involved in such an effect is not yet clear, both prostaglandin-dependent and -independent effects have been proposed. Using HT-29 Glc(-/+)cells, which originate from a human colon adenocarcinoma, we demonstrated in this study a dose-dependent effect of millimolar concentration of aspirin on cell growth that was concomitant with a rapid accumulation of the cells in the G0/G1 phase, followed by an accumulation in the G2/M phase and by a minor increase in the proportion of cells undergoing nuclear condensation. Cell membrane integrity and cell release into the culture medium were not affected by this treatment. The aspirin effects were apparently unrelated to prostaglandin biosynthesis inhibition, since although these cells were found to express high levels of cyclooxygenase 1 (COX-1) and low levels of COX-2 proteins, they did not produce any measurable net amounts of prostaglandins, based on both utilization of radiolabelled arachidonic acid and the radioimmunoassay of prostaglandins E2 and F2 alpha. In contrast, we identified polyamine biosynthesis as a cellular target of aspirin, since the treatment of HT-29 Glc(-/+) cells with aspirin reduced the flux of L-ornithine through ornithine decarboxylase, an effect that could not be explained by an acute action of the drug on the ornithine decarboxylase catalytic activity. Since polyamine biosynthesis is strictly necessary for HT-29 cell growth, our data suggest that reduced flux through ornithine decarboxylase may participate in the antiproliferative activity of aspirin towards colonic tumoral cells. It is concluded that in HT-29 Glc(-/+) cells that are not functional for prostaglandin production, aspirin can affect cell growth, cell cycle, and polyamine biosynthesis without affecting cell membrane integrity.

Adenocarcinoma↗

PubMed2003

[Biology of man-mosquito Plasmodium transmission].

The transmission of Plasmodium is a complex process that requires the encounter of three organisms: the parasite, the host and the mosquito vector. For a better understanding, the transmission of this parasite can be divided in four cyclical steps: 1) the development in man, including gametocytogenesis, 2) the transfer from man to mosquito, 3) the sporogonic development in the mosquito, 4) the transfer from mosquito to man. The present article proposes a review of these different aspects and focuses especially to recent biological knowledge on Plasmodium falciparum in the gametocytogenesis issues, infectivity of gametocytes, sporogonic development and natural factors limiting this development.

Animals↗

PubMed2003

[Plasmodium falciparum: epidemiology and man-mosquito transmission and infection in the vector].

The level of malaria transmission is usually estimated by some entomological parameters (entomological inoculation rate or reproductive rate and its seasonal variations). However, only one aspect of the malaria transmission is explored by this way, i.e. the transmission of Plasmodium from mosquito to man. The transmission from man to mosquito, the development of parasite in the mosquito midgut, and the role of transmission blocking immunity remain poorly documented. Recent studies on vaccination with gamete antigens showed that transmission blocking immunity, and the natural infectiousness of gametocytes after treatment underlined the need for taking into account a new aspect of malaria epidemiology concerning the transmission of Plasmodium from man to mosquito. In this paper, authors propose and discuss different new indicators and methods to improve our knowledge on malaria epidemiology.

Animals↗

PubMed2003

[Plague control in Madagascar: evaluation of the efficacy of Kartman baitboxes in urban areas].

A method associating an anticoagulant rodenticide and an insecticide called Kartman bait-box aimed both at fighting reservoir and vectors of plague. It was evaluated in two neighbourhoods of Antananarivo (Madagascar) from October 2002 to May 2003. It involved the local community in the control. The study was carried out in Ambodirano-Ampefiloha refered as treated neighbourhood in which the Kartman bait box were laid out with an anticoagulant rodenticide and an insecticide with a rapid action versus a "pilot neighbourhood", Ankorondrano-Andranomahery in which the boxes were provided with non poisoning bait and non insecticidal white powder. The rodenticide used was Baraki (difethialone 25 ppm) and the insecticide was a powder of Propoxur 3%. The evaluation of effectiveness of this method was based on the four following parameters: (1) the number of dead rats collected daily inside and in the vicinity of the houses, (2) the daily number of baits non consumed in the Kartman bait box, (3) the cheopis index of the rats trapped using the BTS trap, and (4) the flea carrier index of the rats captured monthly with BTS trap. The cheopis index and the flea carrier index of the rats were calculated monthly. The number of rats that died in the treated neighbourhood was of 968 versus 3 in the pilot neighbourhood. The other parameters reached a stable level after 3 months. Between days 120 and 180, the mean number of unconsumed baits was 2.79 in the treated neighbourhood versus 0.14 in the pilot neighbourhood, the flea carriage (percentage of parasitized hosts) was 0% versus 61% in the pilot neighbourhood, and the cheopis index was 0.0 versus 5.0 in the pilot neighbourhood. This study demonstrates that Kartman bait-boxes reached the rat borne and the vectors of plague found in urban area. We propose to use this method extensively both during epidemic and inter-epidemic contexts.

4-Hydroxycoumarins↗

PubMed2003

[Anopheles mascarensis of Meillon 1947, a malaria vector in the middle west of Madagascar?].

Anopheles mascarensis has been demonstrated to be a vector of human malaria in the East coast of Madagascar. Here, we present original data obtained from 1996 to 2003 on the distribution, biology and vectorial capacity of An. mascarensis in the Middle-West of Madagascar. This species is consistently exophilic both for its trophic and resting behaviour. This accounts for the absence of clear impact of any indoor insecticide spraying. This species is mainly zoophilic, but can occasionally bite humans, which explains a low sporozoitic index (1/2218 = 0.045%). The densities of human landing mosquitoes are most of the time very low, with the exception of a peak between May and August at the beginning of the dry season. It implies that the vector's efficiency is very low but not insignificant in the Middle-West of Madagascar, a situation opposite to what is observed on the East coast. The vectorial efficiency of An. mascarensis and An. arabiensis would enable to maintain a low malarial endemicity in the Middle-West, even in the complete absence of An. funestus.

Altitude↗