Reversibility of Schistosoma mansoni-associated morbidity after yearly mass praziquantel therapy: ultrasonographic assessment

A parasitological, clinical and ultrasonographic longitudinal study was undertaken in 1993 in a focus hyperendemic for Schistosoma mansoni infection in the central highlands of Madagascar. All the inhabitants were systematically treated with praziquantel. A complete examination and treatment were repeated each year. Among the 289 villagers who underwent the complete 3 years' follow up, 65.9% excreted eggs at the initial survey and the mean egg count of infected individuals was 202 eggs/g. In 1996, the prevalence of infection was 19.3% with a mean egg count of 27 eggs/g and, among inhabitants aged > 44 years, only one was found to be infected. The proportion of individuals complaining of bloody stool decreased from 24.9% in 1993 to 8.4% in 1996. Compared to the initial clinical examination, the age-adjusted prevalence of splenomegaly was significantly lower in 1996, but remained high: 62% in the 10-14 years age group and 59% in individuals aged > 24 years. Ultrasonographic examination after 3 years of praziquantel therapy showed a marked decrease of the overall prevalence of schistosomal hepatic fibrosis, from 28% in 1993 to 10.3% in 1996. This improvement had already been achieved during the second year of follow-up for most subjects. Usually, the reversal of morbidity affected individuals classified as stage 1 at the beginning of the study. Stage 3 was not observed in the last 2 surveys. One patient's ascites disappeared during the follow-up, associated with a significant reversal of periportal fibrosis. Our results indicate that repeated praziquantel therapy can lead to improvement of liver morbidity and the prevention of the development of schistosomal hepatic fibrosis, even in an old-established hyperendemic focus.

Metabolism of 14C-moxisylyte after percutaneous application in hairless rat

The pharmacokinetics of 14C-thymoxamine (4-(2-dimethylaminoethoxy)-5-isopropyl-2-methyl phenyl acetate, CAS 54-32-0, moxisylyte, Carlytène) were studied in female hairless rats following different administration routes: oral, intravenous or percutaneous. After percutaneous administration, the half-life of elimination of 14C-thymoxamine and its metabolites was longer (t 1/2 = 15 h) than after oral or intravenous administration (t 1/2 = 9 h). The penetration/resorption phenomenon of thymoxamine base mainly located in the horny layer could explain the high value of the pseudo half-life of elimination observed after percutaneous administration. Due to the absorption slower than elimination, this special pharmacokinetics had to be considered as a flip-flop model. The type and proportions of thymoxamine metabolites recovered in plasma varied according to the route of administration. The unconjugated metabolites, desacetyl-thymoxamine (DAT) + desacetyl-desmethyl-thymoxamine (DMAT), were observed only after intravenous or percutaneous administration, they represented 12% and 15%, respectively. They were never observed after oral administration suggesting the existence of a hepatic first-pass metabolism. The other metabolites observed were sulphate conjugates and glucuronides of DAT + DMAT. The values of sulfoconjugates were constant with each administration route (21%), whereas glucuronides increased with oral administration. In conclusion, the pharmacokinetics of percutaneous thymoxamine presented two main features: the drug absorption was high and durable (t 1/2 = 15 h); the cutaneous application allowed to avoid the hepatic first-pass metabolism.

Plague, a reemerging disease in Madagascar

Human cases of plague, which had virtually disappeared in Madagascar after the 1930s, reappeared in 1990 with more than 200 confirmed or presumptive cases reported each year since. In the port of Mahajanga, plague has been reintroduced, and epidemics occur every year. In Antananarivo, the capital, the number of new cases has increased, and many rodents are infected with Yersinia pestis. Despite surveillance for the sensitivity of Y. pestis and fleas to drugs and insecticides and control measures to prevent the spread of sporadic cases, the elimination of plague has been difficult because the host and reservoir of the bacillus, Rattus rattus, is both a domestic and a sylvatic rat.

[The reconquest of the Madagascar highlands by malaria]

A strong malaria epidemic with a high mortality rate occurred on the Madagascar Highlands in 1986-88. Vector control and free access to antimalaria drugs controlled the disease. The authors have searched for the causes of the epidemic to propose a strategy avoiding such events. The Highlands on Madagascar were known as malaria free. In 1878 a very severe epidemic flooded all the country. Development of irrigated ricefields which house both An. arabiensis and An. funestus had created a new anthropic environment. Moreover manpower imported from malarious coastal areas for rice cultivation and also for building large temples, could have brought P. falciparum. After several outbreaks the disease became endemic up to 1949. In 1949 a malaria eradication programme based on DDT spraying and drug chemoprophylaxis and chemotherapy was launched. By 1960 malaria was eliminated and DDT spraying cancelled. Only 3 foci were kept under surveillance with irregular spraying until 1975. The prophylaxis and treatment centres ("centres de nivaquinisation") were kept open up to 1979. The catholic dispensary of Analaroa, 100 km N.E. of Tananarive, opened in 1971 and worked without interruption up to now. The malaria diagnosis has always been controlled by microscopy. Its registers are probably the more reliable source of information on malaria in the area. They show that malaria was already present on the Highlands in 1971 but at a low prevalence; in 1980 when the "centres de nivaquinisation" were closed the number of cases increased by three times the progressive increase of the number of cases became exponential from 1986 to 1988 which was the peak of the epidemic; malaria remained at a high level until the end of 1993; yearly DDT spraying since 1993 have decreased the number of malaria cases among the dispensary attendants by 90%. The epidemic peak of 1988 was well documented by the Pasteur Institute of Madagascar around Tananarive. Before the epidemic started it was observed a come back of An. funestus which had been previously eliminated of most of the villages by DDT spraying. More than an epidemic the malaria increase in 1988 was a reconquest by malaria of the land from which it had been eliminated in the years 1950. This episode became dramatic because the lack of immunity of the population and the shortage of medicaments. The global warming which was advocated to explain the epidemic has no responsibility because the temperature on the Madagascar Highlands has not changed during the last 30 years. Also the cyclones do not seem to have played any role. It is very likely that the gradual decline of control measures, first DDT spraying, later drug distributions, had the main responsibility in the Highlands drama. Everywhere An. funestus reached a high level during the time where the parasite reservoir was rebuilding. They synergised each other. These findings should be taken in account in drawing the strategy planning for the next years.

Experimental studies on acute and chronic action of azelastine on nasal mucosa in guinea pigs, rats and dogs

Azelastine (CAS 37932-96-0) nasal spray (Allergodil, Rhinolast, Astelin) was investigated in acute experiments in guinea pigs and after a 26-week local application period with daily repeated administration for effects on ciliary beat activity (acute experiments) and morphology of nasal mucosa. The commercially available spray did not inhibit ciliary beat activity in guinea pigs nor did it cause any inflammatory or atrophic changes after 26-week daily local application on nasal mucosa in rats and dogs.

Neurocysticercosis: a major aetiological factor of late-onset epilepsy in Madagascar

To assess the impact of cysticercosis on public health in Madagascar, we compared patients > 15 years with late-onset epilepsy to non-epileptic controls in a matched case-control study. The association between epilepsy and cysticercosis was studied by enzyme-linked immunoelectrotransfer blot (EITB) assay for antibodies specific to Taenia solium. The EITB assay was performed on 104 pairs of sera specimens and on 95 pairs of cerebrospinal fluid (CSF) specimens. Depending on whether we consider the results obtained from sera or from CSF, we obtain for the population attributable risk percent of cysticercosis in late-onset epilepsy two slightly different estimates: 22.3% and 17.6%. Therefore cysticercosis is a major aetiological factor of late-onset epilepsy in Madagascar. In the control group, the frequency of positive results, especially in CSF specimens (7.4%), confirms the existence of asymptomatic cases of neurocysticercosis.

In vivo and in vitro studies on the sonographical detection of Ascaris lumbricoides

Intestinal ultrasound, a frequently applied diagnostic tool in industrialized nations, has recently also been introduced in tropical regions. This study attempts to describe the anatomical and sonographical features of Ascaris lumbricoides in the human intestine. In the course of a schistosomiasis morbidity study in Madagascar, 581 inhabitants of a rice-farming village on the high plateau of the island had their stools examined by means of a modified Kato-Katz thick smear technique (four slides per sample); 53% had eggs of Ascaris lumbricoides in their stools. Twenty-two individuals underwent intestinal ultrasound examination and, in six cases, Ascaris lumbricoides was visualized. All six patients showed eggs upon stool examination. At ultrasound, the parasite was seen as a large, curved echogenic strip (4-6 mm in diameter) with an inner, anechoic, longitudinal canal. The image resembled a winding highway, the central structure representing the pseudocoel of the parasite. Patients were treated with mebendazole. The excreted worms of one patient were scanned under water, showing the same characteristics as in vivo. We conclude that Ascaris lumbricoides has a characteristic sonographical appearance and should not be a confounding factor in studies using intestinal ultrasound.

In vivo footprinting of the interaction of proteins with DNA and RNA

Analysis of the interaction of proteins with either DNA or RNA sequences by in vivo footprinting involves two steps: (i) the in situ modification of nucleic acids by the footprinting reagent and (ii) the visualization of the footprints. Ligation-mediated PCR (LM-PCR) procedures provide a level of sensitivity and specificity that is suitable for visualization of footprints of single-copy genes or low-abundance mRNAs in higher eukaryotes. In this article, we discuss several of the technical aspects of these multistep procedures that contribute to the quality of the results, particularly the parameters that affect the specificity and fidelity of the reactions: (i) the design of the primers, which is important to achieve optimal specificity; (ii) the choice of polymerases so that the amplified material represents faithfully the initial nucleic acid population; and (iii) the impact of the plateau effect within the PCR on the interpretation of the data. We then discuss aspects of in vivo nucleic acid manipulation that may affect the quality of the footprinting image, in particular the choice of the footprinting reagent and its condition of use (e.g., on intact or permeabilized cells or prepared nuclei) and the extent of nucleic acid modification. Finally, we provide detailed experimental procedures corresponding to the techniques we have developed or modified: LM-PCR, reverse ligation-mediated PCR, and nuclease treatment of RNAs in vivo.

[The impact of curtains impregnated with deltamethrin on the vectors and morbidity of malaria: results in Ankazobe, on the plateaus of Madagascar]

To evaluate the efficacy of deltamethrin impregnated curtains on malaria morbidity in a low transmission area, we studied volunteer families in the village of Ankazobe in the Madagascar Highlands from February 1993 to June 1994. After randomization, we provided 46 houses having 244 inhabitants with impregnated curtains (I) and 45 others having 257 inhabitants with nonimpregnated curtains (NI) as controls. We first estimated the number of mosquito bites in the protected versus nonprotected households. Every month, we captured mosquitos on humans in 6 houses per night for 4 nights. For the I group compared to the NI group, the number of bites by the Anopheles funestus vector per human per night was reduced by 64% in 1993 and 39% in 1994. We also analyzed the malaria morbidity. Malaria morbidity was defined as patients having both temperatures greater than 37.5 degrees C and Plasmodium falciparum parasitemia greater than 1500/microliter with clinical symptoms. From February to July 1993, we observed no significant difference in morbidity: there were 103 cases of malaria among 244 inhabitants of the I group and 117 cases among 257 inhabitants of the NI group. However, during the period of highest transmission from March to May in 1993, there were significantly fewer cases in the I group (68) than in the NI group (94). From January to June 1994, the difference was clear: only 35 malaria cases were observed among the 208 inhabitants of the I group as compared to 65 cases among the 223 inhabitants of the NI group (Chi square = 9.17, p = 0.0024). Inhabitants of the I group could have been contaminated before the curtains were set up. After treatment of the cases and use of curtains during the second year, we observed a reduction in the number of mosquito bites and malaria cases. The small size of the trial made the interpretation of the data difficult. Nonetheless, the results tentatively support the use of impregnated curtains as an antimalaria tool in an integrated control program.

High prevalence of serological markers of cysticercosis among epileptic Malagasy children

Neurocysticercosis (i.e. cerebral localization of the metacestode larvae of Taenia solium) is believed to be a major cause of late onset epilepsy in non-Muslim developing countries. To define its role in childhood epilepsy in Madagascar, analysis of serological markers of cysticercosis was performed in 256 children with unexplained epilepsy and in 113 controls. Sera were considered positive when high titres in ELISA were present together with at least one of the bands 13, 14, 18, 21, 24 or 32 kD on Western blot. Altogether, 17.6% of the patients versus none of the controls were seropositive using these criteria. When analysing the bands of the Western blot, those of 13, 14 and 18 were significantly more frequently detected in sera of epileptic children than in sera of controls. Neurocysticercosis can be considered the main cause of secondary childhood epilepsy in our country, Madagascar being one of the most important foci in the world.

Schistosoma haematobium infection in western Madagascar: morbidity determined by ultrasonography

To assess the morbidity related to Schistosoma haematobium infection in western Madagascar, an ultrasonographic examination was performed of 574 inhabitants > 5 years old in a village in an old-established endemic area where no prior systematic antischistosomal treatment had been given. The overall prevalence of infection was 75.9% and the geometric mean egg count of positive individuals was 36 eggs/10 mL of urine. Recent haematuria had been experienced by 31.8% of individuals. Echographic abnormalities of the urinary tract were present in 50.5% of individuals: they were more frequent in males. Bladder wall lesions were observed in 93.1% of individuals with ultrasonographic changes, irregularities of the inner surface being the most common finding. Congestive changes were noted in 8.4% of kidneys, but we observed only 4 severe congestions. Bladder lesions and congestive changes in kidneys predominated in youth; their presence and severity were significantly correlated with egg excretion. In 12 inhabitants, grade 1 periportal fibrosis was observed, but no significant association was found with S. haematobium infection. In a control village, where the prevalence of S. haematobium infection was 7%, moderate congestion of kidneys was observed in 2% of examined inhabitants, and bladder changes in 6%, with a significant relationship with S. haematobium infection.

[Rice: source of life and death on the plateaux of Madagascar]

Since the 17th century, Europeans travelling in Madagascar described the contrast between the fever-free Plateau and the fever-ridden coasts. The former were inhabited by people of Asiatic origins and the latter by African migrants. At the end of the 18th century, "Merina" kings developed land irrigation and rice cultivation, using manpower from the coasts. Since then, rice has become a monoculture covering most of the arable lands of the Highlands. The first malaria epidemic occurred in the Tananarive area in 1878, and rapidly spread throughout the Plateau. The mortality rate was high. A second epidemic in 1895 may have been a resurgence of the previous one. Subsequently, malaria became meso-epidemic despite control measures, mainly consisting of larvivorous fishes, quinine treatment and prophylaxis. In 1949, an eradication program was launched based on DDT house-spraying and chloroquine prophylaxis in children. It was very successful on the Highlands where malaria disappeared, in 1962. Spraying was cancelled and only three small foci remained under surveillance. In 1987 and 1988, a malaria outbreak devastated the plateau. Subsequently, intensive spraying operations brought the situation under control by 1993. The main malaria vector on the Madagascar Highlands is An. funestus. More than 95% of its breeding sites are in the rice fields just before the harvest and afterwards in the fallow lands. The vector peak and the corresponding peak of malaria cases occur between February and May, depending on the farming calender. The second but less important vector, An. arabiensis, breeds in the rice fields just after seeding when the surface water is sunlit. Although rice fields remain the main source of this vector, it also breeds in rainwater pods and borow-pits. Malaria vectors on the plateau are products of human activities of rice cultivation, which is the basis of the economy. The epidemiological importance of rice fields varies greatly from one country to another. In Southeast Asia, the rice fields harbor several anopheline species most of which are only vectors of P. vivax. In West Africa where malaria is holoendemic, they produce large populations of An. gambiae; however, the malaria pattern is unaltered and remains at peak levels. In the dry areas of southern Madagascar, the vector An. funestus and meso-hyperendemic malaria are restricted to areas of cultivated rice. In West and Central Africa, An. funestus is never found in rice fields even though it is common in marshes. In Madagascar, this vector breeds in irrigated rice fields. Because it is practically impossible to control anophelines in rice fields by chemical, biological and ecological methods on the Highlands of Madagascar, house-spraying remains the best method for mass malaria control. Bed-nets impregnated with pesticides may offer an alternative, but their use is resisted by the local population.

Pharmacokinetics study of 14C-moxisylyte after percutaneous application to hairless rat

The percutaneous pharmacokinetic parameters of 14C-thymoxamine (4-(2-dimethylaminoethoxy)-5-isopropyl-2-methyl phenyl acetate, moxisylyte, Carlytène) were studied on female hairless rats. Animals received 30.3 mg/kg of thymoxamine-base (CAS 54-32-0) percutaneously (dorsal skin). The decrease of the radiolabelled compound on the skin surface (drug penetration) and the appearance of the total radioactivity in plasma (drug absorption) were measured. The time-course study of the total radioactivity measured on the skin surface indicates a biphasic profile with a rapid decrease during the first h (t1/2 from 0 to 4 h = 1.4 h) and then a less rapid one (t1/2 after 4 h approximately 29 h). Plasma data demonstrated that 14C-thymoxamine was rapidly and almost entirely absorbed (91%) after percutaneous application. The values of absorption parameters suggest that thymoxamine is a compound with a high absorption process using this route of administration. The t(max) value was about 2 h and the half-life of absorption was 0.70 h. Compared to the apparent half-life of elimination observed after oral or i.v. administration (t1/2 = 9 h),the elimination phase of thymoxamine was relatively rapid after percutaneous administration (t1/2 = 15 h). The penetration /absorption phenomenon of thymoxamine base mainly located in the horny layer could explain the higher value of the half-life of elimination observed after percutaneous administration.

[Drug resistance and therapeutic strategy]

In Madagascar, Plasmodium falciparum resistance to chloroquine was clinically suspected in 1975 by Goasguen and demonstrated in 1981 by Arronson et al. Since then, many studies were conducted throughout the island, in the North, South, East and West, on the high Plateau and on the coasts. Two methods were used, including an in vivo method similar to the therapeutic standard protocol of the WHO, and an in vitro method employing the semi-microtest of Le Bras and Deloron. From 1982 to 1986, the 291 in vivo tests performed showed that 20% of the strains were of the types R1 or R2 (SR1 included). From 1987 to 1994, of the 621 in vivo tests performed, 369 (59.4%) of the cases responded to treatment. The deterioration of the situation observed in 1988 (Lepers et al.) seemed to be stabilized (Ringwald et al.). No strain of the type R3 was found. In conclusion, we report the absence of strain type R3 and also the clinical efficacy of chloroquine. The action of chloroquine was spectacular on the fevers and there was remarkable reduction of the parasitaemia. Thus, for treating outbreaks of simple malaria in Madagascar, chloroquine remains the best choice if it is administered at an efficacious dose.

Fatal mass poisoning in Madagascar following ingestion of a shark (Carcharhinus leucas): clinical and epidemiological aspects and isolation of toxins

In November 1993, 188 people were admitted to hospital after eating the meat from a single shark (Carcharhinus leucas) in Manakara, a medium-sized town on the south-east coast of Madagascar. This shark and its meat had no unusual characteristics. The attack rate was about 100%. The first clinical signs appeared within 5-10 hr after ingestion. The patients presented with neurological symptoms almost exclusively, the most prominent being a constant, severe ataxia. Gastrointestinal troubles, like diarrhoea and vomiting, were rare. The overall case mortality ratio was close to 30% among the 200 poisoned inhabitants. There were no reports of previous similar poisonings in this area, and fishermen in Manakara usually eat this kind of shark without problems. Bacteriological and chemical causes were eliminated. Two liposoluble toxins were isolated from the liver and tentatively named carchatoxin-A and -B, respectively. They were distinct from ciguatoxin in their chromatographic properties.

Glucocorticoids and protein kinase A coordinately modulate transcription factor recruitment at a glucocorticoid-responsive unit

The rat tyrosine aminotransferase gene is a model system to study transcriptional regulation by glucocorticoid hormones. We analyzed transcription factor binding to the tyrosine aminotransferase gene glucocorticoid-responsive unit (GRU) at kb -2.5, using in vivo footprinting studies with both dimethyl sulfate and DNase I. At this GRU, glucocorticoid activation triggers a disruption of the nucleosomal structure. We show here that various regulatory pathways affect transcription factor binding to this GRU. The binding differs in two closely related glucocorticoid-responsive hepatoma cell lines. In line H4II, glucocorticoid induction promotes the recruitment of hepatocyte nuclear factor 3 (HNF3), presumably through the nucleosomal disruption. However, the footprint of the glucocorticoid receptor (GR) is not visible, even though a regular but transient interaction of the GR is necessary to maintain HNF3 binding. In contrast, in line FTO2B, HNF3 binds to the GRU in the absence of glucocorticoids and nucleosomal disruption, showing that a "closed" chromatin conformation does not repress the binding of certain transcription factors in a uniform manner. In FTO2B cells, the footprint of the GR is detectable, but this requires the activation of protein kinase A. In addition, protein kinase A stimulation also improves the recruitment of HNF3 independently of glucocorticoids and enhances the glucocorticoid response mediated by this GRU in an HNF3-dependent manner. In conclusion, the differences in the behavior of this regulatory sequence in the two cell lines show that various regulatory pathways are integrated at this GRU through modulation of interrelated events: transcription factor binding to DNA and nucleosomal disruption.

Hepatocyte nuclear factor 3 determines the amplitude of the glucocorticoid response of the rat tyrosine aminotransferase gene

Hepatocyte nuclear factor 3 (HNF3) recognizes two apparently distinct classes of sequence. However, a detailed mutational analysis of a representative binding site of each class reveals that these sequences display common features. We propose a unified consensus sequence for HNF3-binding sites. The basis of the sequence specificity of the interaction of HNF3 with DNA is analyzed in light of the recently determined structure of an HNF3-DNA complex (Clark et al., Nature 364, 412-420, 1993). Particularly, our study reveals that the DNA site used for this structural analysis is too short to account for all HNF3-DNA interactions. The better knowledge of the sequence determinant recognized by HNF3 has allowed us to analyze its function in the glucocorticoid response of the rat tyrosine aminotransferase (TAT) gene. This response is mediated through a complex array of neighboring and overlapping transcription factor binding sites. Selective inactivation of the HNF3-binding sites in this glucocorticoid response unit (GRU) allows us to demonstrate unambiguously that they play a major role in the amplitude of the glucocorticoid response. Furthermore, HNF3 beta overexpression results in a stimulation of the glucocorticoid response that is dependent on the integrity of its binding sites. We also show that the relative level of HNF3 determines the extent of the contribution of one of the glucocorticoid receptor binding sites. Our results indicate that HNF3 accounts for most of the liver-specific activity of this GRU.

Ultrasonographical assessment of morbidity in schistosomiasis mansoni in Madagascar: a community-based study in a rural population

Between June and November 1993, a parasitological, clinical and ultrasonographical survey was carried out in the mid west of Madagascar, among the whole population of a village where Schistosoma mansoni was endemic. S. mansoni eggs were found in the stools of 61.8% of the 544 individuals examined; the highest prevalence of infection (85.7%) was observed in the 15-19 years old age group. The most intense infections were recorded in the 10-14 years age group, in which the geometric mean egg count was 265 eggs/g of faeces and 34.3% of the individuals excreted more than 400 eggs/g. The egg count decreased steadily from the age of 15 years. Ultrasonographical examination was performed in 482 inhabitants older than 2 years: 29% of them presented definite schistosome associated liver alterations according to the proposals for staging S. mansoni infection made by the World Health Organization Cairo working group. Stage 3 was never observed in subjects under 30 years old. This is consistent with the need for a long-standing infection before serious lesions occur. A significant relationship between egg count and degree of liver alterations was found only in the 20-29 years age group.

Metabolism of 14C-moxisylyte in hairless rat. Comparison between intravenous and oral route

The pharmacokinetics of 14C-thymoxamine (4-(2-dimethylaminoethoxy)-5- isopropyl-2-methyl phenyl acetate hydrochloride) (moxisylyte, Carlytène) was studied on female hairless rats. Animals received 5 mg/kg of thymoxamine-HCl (CAS 964-52-3) intravenously or orally. 14C-thymoxamine was both rapidly and entirely absorbed after oral administration, Tmax value was observed at 0.25 h. The decrease of the total radioactivity followed a biexponential mode. After intravenous and oral administration, the apparent half-live of distribution were 0.20 and 0.31 h, respectively, whereas the apparent half-live of elimination were 9.6 (i.v.) and 8 h (p.o.). The nature and proportions of thymoxamine metabolites recovered in the plasma varied according to the route of administration. After intravenous administration, desacetyl-thymoxamine (DAT) + desacetyl-desmethyl-thymoxamine (DMAT), sulphate conjugates and glucuronides of DAT + DMAT represented 12, 21 and 63%, respectively. After oral administration, the values were 0, 21 and 79%, respectively. These results underlined the importance of the hepatic first-past effect which induced the disappearance of DAT and DMAT, and increased the levels of glucuronides when thymoxamine was orally administered. The level of sulphate conjugates for DAT and DMAT seems always constant.

[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.

Participation of Ets transcription factors in the glucocorticoid response of the rat tyrosine aminotransferase gene

We have previously shown that two remote glucocorticoid-responsive units (GRUs) of the rat tyrosine aminotransferase (TAT) gene contain multiple binding sites for several transcription factor families, including the glucocorticoid receptor (GR). We report here the identification of two novel binding sites for members of the Ets family of transcription factors in one of these GRUs. One of these binding sites overlaps the major GR-binding site (GRBS), whereas the other is located in its vicinity. Inactivation of the latter binding site leads to a twofold reduction of the glucocorticoid response, whereas inactivation of the site overlapping the GRBS has no detectable effect. In vivo footprinting analysis reveals that the active site is occupied in a glucocorticoid-independent manner, in a TAT-expressing cell line, even though it is located at a position where there is a glucocorticoid-dependent alteration of the nucleosomal structure. This same site is not occupied in a cell line that does not express TAT but expresses Ets-related DNA-binding activities, suggesting the existence of an inhibitory effect of chromatin structure at a hierarchical level above the nucleosome. The inactive Ets-binding site that overlaps the GRBS is not occupied even in TAT-expressing cells. However, this same overlapping site can confer Ets-dependent stimulation of both basal and glucocorticoid-induced levels when it is isolated from the GRU and duplicated. Ets-1 expression in COS cells mimics the activity of the Ets-related activities present in hepatoma cells. These Ets-binding sites could participate in the integration of the glucocorticoid response of the TAT gene with signal transduction pathways triggered by other nonsteroidal extracellular stimuli.

[Schistosomiasis mansoni infection in a hyperendemic region of midwestern Madagascar: epidemiology, morbidity and secondary effects of praziquantel treatment]

The examination of 544 inhabitants (93.2% of the whole population) of a village in the middle west of Madagascar, where Schistosoma mansoni is hyperendemic and where no previous antischistosomal treatment had been delivered at a community level, showed a prevalence rate of 61.8%. The highest prevalences and the most intense infections were observed in the 10-24 age group. The egg count decreases dramatically from the age of 25. A highly significant relationship was found between recent histories of bloody diarrhoea and S. mansoni eggs excretion. Clinical examination showed a high frequency of splenomegalies (62.2% > or = stade 2 Hackett), with two modes: one in the 10-14 age group and the other in the 35-39 age group. The respective liability of S. mansoni and malaria remain to be clarified. Side effects after treatment of the entire population with praziquantel were observed in 27.2% of treated individuals. Side effects occurred mainly in infected people. A highly significant relationship was found between intensity of infection and frequency of these side effects which are essentially mild and disappear in the 24 hours.

Comparison of thymoxamine permeation between hairless rat and horse penile mucous membrane using an in vitro diffusion model

Moxisylyte (or thymoxamine) administered intracavernously is known to improve erection in organically impotent patients. Prior to drug administration by percutaneous route, we have to define its in vitro permeation parameters after application of thymoxamine on both rat skin and horse penile mucous membrane. 24 h after drug application, the percentages of thymoxamine which diffused through the penile mucous and the rat skin were 88 and 75%, respectively. Thymoxamine flux varied according to the biological membrane tested. With regard to the penile mucous membrane, a maximal flux (1,774 nmol.h-1.cm-2) was observed 2.5 h after drug application, whereas for the rat skin a maximal flux (657 nmol.h-1.cm-2) was noted at 3.5 h. Thymoxamine flux decreased rapidly in the penile mucous membrane. This decrease was slower when thymoxamine penetrated the rat skin; the difference could be due to a different morphology of the tested biological membranes. In contrast to the rat skin, the external keratinized layer was absent in the penile mucous membrane. In conclusion, the ability of thymoxamine to penetrate easily and rapidly the biological membrane, and particularly the penile mucous membrane, suggests that thymoxamine could reach the pharmacological target represented by the corpus cavernosum of the penis.

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.