A geographical approach to identify sleeping sickness risk factors in a mangrove ecosystem

OBJECTIVES

To provide a better understanding of sleeping sickness transmission and spread in mangrove areas to optimize its control.

METHODS

In the Forecariah mangrove area, Guinea, 19 sleeping sickness cases and 19 matched controls were followed up in their living areas (at home, in fields and at water points). All occupational sites and pathways were mapped and then placed in their environmental context.

RESULTS

The sleeping sickness cases displayed a significantly broader and more diverse spatial occupation than the controls. They covered double the daily walking distances of controls and had on average two more occupational sites, most of which were located in mangrove forests. Activities with a higher transmission risk (rice culture, attendance of pirogue jetties) were identified as well as high-risk areas and pathways.

CONCLUSIONS

An entomological control strategy targeting transmission risk areas is proposed. Its implementation in a control programme would reduce by 86% the efforts needed for a classical vector control programme throughout the area. Medical surveys set up at specific locations, such as pirogue jetties and high-risk paths, should also enable better targeting of the population at highest risk.

[Major cardiovascular risk factors according to gender in the hospital environment]

AIM

The study aims to describe cardiovascular risk factor according to gender in hospital.

MATERIAL AND METHODS

Il was a prospective study from april 2007 to march 2008 including 146 highblood pressure patients from 2 medical centre in Bamako. Gathering and analysis were performed with SPSS 11.

RESULTS

67% were female, the mean age reached 48,82. the BMI was significantly higher in female (P <0,001). Female were mainly registered between 30 and 44 years, and male between 45-59 years. Overweight and obesity were more represented in female and obesity in 30-44 years old patients. Isolated highblood pressure was found in 58,90%, 7,53% of patients had the 3 major cardiovascular risk factor

CONCLUSION

Isolated highblood pressure was by far the most frequent. Although the cardiovascular risk rises with the others associations, they were rare and don't significantly differ in each gender. The tendency to overweight and obesity in female should be confirmed by others studies.

Humoral and cell-mediated immunity to MSP3 peptides in adults immunized with MSP3 in malaria endemic area, Burkina Faso

We performed a single-blind, randomized phase 1 trial of the long synthetic peptide (LSP) of merozoite surface protein-3 (MSP3) in adults living in Burkina Faso. Thirty eligible volunteers were randomized to receive either the MSP3-LSP candidate vaccine or tetanus toxoid vaccine as a control. A dose of each vaccine was administered on days 0, 28 and 112 and the vaccine was formulated with aluminium hydroxide. Humoral immune responses were assessed by ELISA at days 0, 28, 56, 112, 140, 252 and 365 and cell-mediated immune responses by lymphoproliferation assay and by ELISA on days 0, 56 and 140. IgG responses to four peptides of MSP3 were similar in both vaccine groups. Higher IgG concentrations were recorded after the beginning of malaria high transmission season in both vaccine groups. The lymphocyte proliferation and the production of IFN-γ in response to stimulation with the four overlapping peptides increased following vaccination in the MSP3-LSP vaccine group, but did not change appreciably in the control group. In contrast to natural infection, MSP3-LSP did not boost humoral responses to the four overlapping peptides of MSP3 to any detectable degree in our semi-immune adult. MSP3-LSP may be more immunogenic in young children with little or no acquired immunity.

HIV, HCV, HBV and syphilis rate of positive donations among blood donations in Mali: lower rates among volunteer blood donors

Good data on background seroprevalence of major transfusion transmitted infections is lacking in Mali. We gathered data on the rate of positive donations of human immunodeficiency virus (HIV), hepatitis C virus (HCV), hepatitis B virus (HBV) and syphilis among blood donations in Mali for calendar year 2007. Donations with repeatedly reactive results on screening enzyme immunoassay (EIA) were considered to be seropositive. Rate of positive donations per blood unit collected was 2.6% for HIV, 3.3% for HCV, 13.9% for hepatitis B surface antigen (HBsAg) and 0.3% for syphilis. For HIV, HBsAg and syphilis, rate of positive donations was significantly (p<0.001) higher among donations from replacement donors than those from volunteer donors, while HCV rate of positive donations was similar in the two groups. Rate of positive donations was also significantly (p<0.0001) lower in blood units from regular than from first-time donors. These data reinforce WHO recommendations for increasing the number of regular, volunteer blood donors in Africa.

Mapping sleeping sickness in Western Africa in a context of demographic transition and climate change

Human population growth, climate change and economic development are causing major environmental modifications in Western Africa, which will have important repercussions on the epidemiology of sleeping sickness. A new initiative, the Atlas of human African trypanosomiasis (HAT), aims at assembling and geo-referencing all epidemiological data derived from both active screening activities and passive surveillance. A geographic database enables to generate up-to-date disease maps at a range of scales and of unprecedented spatial accuracy. We present preliminary results for seven West African countries (Benin, Burkina Faso, Côte d'Ivoire, Ghana, Guinea, Mali and Togo) and briefly discuss the relevance of the Atlas for future monitoring, control and research activities.

[Change of antimalarial first-line treatment in Burkina Faso in 2005]

Burkina Faso has recently changed the antimalarial drug policy to artesunate/amodiaquine or artemether/lumefantrine as the first-line antimalarial drug and sulfadoxine/pyrimethamine for the intermittent preventive treatment in pregnant woman. Before the implementation of this new strategy we conducted an in vivo efficacy study with chloroquine or sulfadoxine/pyrimethamine for treatment of uncomplicated Plasmodium falciparum malaria in urban area of Burkina from September to December 2003. Chloroquine (25 mg/kg over 3 days) or sulfadoxine/pyrimethamine (25 mg/kg + 0.025 mg/kg single dose) was administered respectively to 137 and 125 children aged from 6 to 59 months old in a randomized, opened study. Follow up extended over 28 days using modified WHO protocol. After adjusting the results by PCR, treatment failures rates were 63.4% (83/131) and 13.8% (17/123) respectively for chloroquine and sulfadoxine/pyrimethamine. These results with other observations have justified the change of malaria therapy policy in Burkina Faso in 2005.

Do antibody responses to malaria vaccine candidates influenced by the level of malaria transmission protect from malaria?

OBJECTIVES

To examine whether the humoural response to malaria vaccine candidate antigens, Plasmodium falciparum [circumsporozoite repetitive sequence (NANP)(5) GLURP fragments (R0 and R2) and MSP3] varies with the level of malaria transmission and to determine whether the antibodies (IgG) present at the beginning of the malaria transmission season protect against clinical malaria.

METHODS

Cross-sectional surveys were conducted to measure antibody response before, at the peak and at the end of the transmission season in children aged 6 months to 10 years in two villages with different levels of malaria transmission. A cohort study was performed to estimate the incidence of clinical malaria.

RESULTS

Antibodies to these antigens showed different seasonal patterns. IgG concentrations to any of the four antigens were higher in the village with high entomological inoculation rate. Multivariate analysis of combined data from the two villages indicated that children who were classified as responders to the selected antigens were at lower risk of clinical malaria than children classified as non-responders [(NANP)(5) (incidence rate ratio (IRR) = 0.65, 95% CI: 0.46-0.92; P = 0.016), R0 (IRR = 0.69, 95% CI: 0.48-0.97; P = 0.032), R2 (IRR = 0.73, 95% CI: 0.50-1.06; P = 0.09), MSP3 (IRR = 0.52, 95% CI: 0.32-0.85; P = 0.009)]. Fitting a model with all four antibody responses showed that MSP3 looked the best malaria vaccine candidate (IRR = 0.63; 95% CI: 0.38-1.05; P = 0.08).

CONCLUSION

Antibody levels to the four antigens are affected by the intensity of malaria transmission and associated with protection against clinical malaria. It is worthwhile investing in the development of these antigens as potential malaria vaccine candidates.

[Comparative impact of three malaria preventive regimens during pregnancy on maternal anemia due to malaria in Burkina Faso]

OBJECTIVES

The main objective of this study was to compare the efficacy of three regimens of malaria prevention during pregnancy for the reduction of anemia between the first and third antenatal consultations. The first treatment arm was the classical weekly chemoprophylaxis with chloroquine; the other two were the intermittent preventive treatment using either three doses of chloroquine or sulfadoxine-pyrimethamine.

DESIGN

We conducted an open, randomized, three-arm study in a rural district of Burkina Faso. A cohort was constituted by 648 pregnant women of any parity.

RESULTS

The hemoglobin gain was more significant with the intermittent preventive treatment using sulfadoxine-pyrimethamine compared to the other treatment arms. The hemoglobin increased from 10.3g/dl (at the first antenatal consultation) to 11.4 g/dl (at the third antenatal consultation). In the three arms of treatment, the chemoprophylaxis reduced the prevalence of moderate anemia and severe anemia. The reduction of moderate anemia was more substantial in the sulfadoxine-pyrimethamine arm (65.6 to 36.7%) at second antenatal consultation (p=0.069) and third antenatal consultation (p=0.014). Conversely, in the two chloroquine arms, there was no significant reduction either at second antenatal consultation (p=0.72) or third antenatal consultation (p=0.55). The prevalence of peripheral parasitemia decreased in all treatment groups. However, it was significantly higher in the sulfadoxine-pyrimethamine group (44.3%).

CONCLUSIONS

Intermittent preventive treatment with three doses of sulfadoxine-pyrimethamine is a more effective strategy to prevent maternal anemia during pregnancy in Burkina Faso.

[Risk factors for ischemic heart disease: a review of 162 cases in Bamako]

The determination of risk factors a low to prevent or to delay the apparition of certain diseases. Our study put out in Cardiology A of Hôpital du Point G. gold to determine the main risk factors of ischemic heart diseases between 162 patients. It appears that all classical risk factors (HBP, Diabetes, obesity, tobacco use, sedentary, menopause, contraceptives, dyslipidemia) were found among patients. It appears particularly that avoidable risk factors such tobacco use among young men, sedentary and obesity play important role in the beginning. So it is possible to deploy an efficient prevention politic.

[Geographic distribution and epidemiology of urinary schistosomiasis in Mali: implications for a control program]

A national survey was conducted in Mali between 1986 and 1990 to determine the geographical distribution of urinary schistosomiasis in order to define an ecologically based national schistosomiasis control programme. Fifty six thousand two hundreds and sixty five individuals randomly selected from 323 villages in the nine ecologically defined areas of the whole country were submitted to urine examination using Filtration Technique. In villages along the Niger and Senegal rivers, in the Dogon Plateau and Office du Niger areas, the prevalence of Schistosoma haematobium infection was the highest, respectively 41.8%, 53.1%, 59.4% et 62.9%. In these areas, more 70% of children aged 7 to 14 years were infected. In the Soudanian and North-Soudanian areas, the prevalence were below 10% and respectively only 5.3% and 11.5% of children aged 7 to 14 years were infected. It is concluded that Schistosoma haematobium infection is of public health importance in dam and irrigation areas and in areas along the Niger and Senegal rivers namely in Kayes, Koulikoro, Segou, Mopti regions and in Bamako district. These areas should be considered as priority areas for active control interventions. The interventions should include community-based mass chemotherapy with praziquantel after community diagnostic using urine examination in school aged children and a good monitoring system.

[Genetic diversity of P. falciparum and pathogenesis of the severe malarial anaemia in children under 5 years old in the province of Boulgou, Burkina Faso]

The clinical presentation of malaria mainly the severe form may be related to Plasmodium falciparum msp-2 (merozoite surface protein 2) specific family To verify this hypothesis, during the high malaria transmission season in 2001; we analyzed the allelic polymorphism of the msp-2 gene of P. falciparum in children under 5 years old with different presentation of malaria in the regional Hospital and at community level in the Boulgou Province (Burkina Faso). A total of 405 children (107 severe malarial anaemia cases, 102 severe malaria cases without severe anaemia and 196 non severe malaria cases) were enrolled in the study. The frequencies of the FC27 were 89.2% in severe malarial anaemia children group, then 89.7% and 86.9% respectively in severe malaria non anaemic children cases and non severe malaria cases (P = 0.4). The frequencies of the 3D7 were 72.5%; 84.1% and 77% respectively severe malaria non anaemic children, severe malarial anaemia cases and non severe malaria cases (P = 0.7). The complexity of the FC27 genotypes was significantly higher in children with severe malaria (with and without severe anaemia) compared to the non severe malarial children (P << 0.001). No significant difference was pointed up in the complexity of the 3D7 genotypes.

Genetic complexity and gametocyte production of Plasmodium falciparum in Fulani and Mossi communities in Burkina Faso

We have examined Plasmodium falciparum gametocyte prevalence, density and their genetic complexity among children of 2 sympatric ethnic groups (Mossi and Fulani) in villages in Burkina Faso. The 2 groups are known to have distinct differences in their susceptibility and immune responses to malaria. We used RT-PCR and sequence-specific probes to detect and type RNA of the gametocyte-specific protein Pfs48/45. There were no differences in detection rates of asexual forms and gametocytes among the 2 groups, using PCR and RT-PCR, respectively. However, there were significant differences in densities of asexual forms and gametocytes, which were both higher among Mossi than Fulani. Both asexual forms and gametocyte densities were influenced by age and ethnicity. Multiple-clone infections with more than 1 gametocyte genotype were equally prevalent among Fulani and Mossi. These differences can most probably be attributed to genetic differences in malaria susceptibility in the 2 ethnic groups.

Impact of mass chemotherapy with praziquantel on Schistosoma haematobium and Schistosoma mansoni infections in Office du Niger, Mali

Aims This study was carried up to assess the impact of mass chemotherapy with praziquantel on the prevalence and intensity of Schistosoma haematobium and Schistosoma mansoni in Office du Niger. Materials and Methods It was a cross sectional study with two passages about which we compared a test group of 7 villages (n=2342) treated in 1989 to a control group of 7 villages (n=2263). Results One year after mass chemotherapy, baseline prevalence rates of Schistoosma haematobium, Schistoaoma mansoni and those of the double infection decreased by 50%, 54% and 62,9% respectively. The geometric mean egg counts of Schistosma haematobium (GMECSh) was reduced by 66.6% and that of Schistosoma mansoni (GMECSm) by 43.4%. However, in spite of mass treatment, the overall prevalence rates of Schistosoma haematobium and mansoni were always higher than 20% in young people aged of 6-19 years. Conclusion These data show that in irrigated area, efficacy of praziquantel is strongly affected by age. This persistance of infection in population raises up several questions according to host immunity, parasite biology and praziquantel efficacy.

In situ calibration and [H+] sensitivity of the fluorescent Na+indicator SBFI

Despite the popularity of Na+-binding benzofuran isophthalate (SBFI) to measure intracellular free Na+ concentrations ([Na+]i), the in situ calibration techniques described to date do not favor the straightforward determination of all of the constants required by the standard equation (Grynkiewicz G, Poenie M, and Tsien RY. J Biol Chem 260: 3440–3450, 1985) to convert the ratiometric signal into [Na+]. We describe a simple method in which SBFI ratio values obtained during a “full” in situ calibration are fit by a three-parameter hyperbolic equation; the apparent dissociation constant ( K d) of SBFI for Na+ can then be resolved by means of a three-parameter hyperbolic decay equation. We also developed and tested a “one-point” technique for calibrating SBFI ratios in which the ratio value obtained in a neuron at the end of an experiment during exposure to gramicidin D and 10 mM Na+is used as a normalization factor for ratios obtained during the experiment; each normalized ratio is converted to [Na+]i using a modification of the standard equation and parameters obtained from a full calibration. Finally, we extended the characterization of the pH dependence of SBFI in situ. Although the K d of SBFI for Na+ was relatively insensitive to changes in pH in the range 6.8–7.8, acidification resulted in an apparent decrease, and alkalinization in an apparent increase, in [Na+]i values. The magnitudes of the apparent changes in [Na+]ivaried with absolute [Na+]i, and a method was developed for correcting [Na+]i values measured with SBFI for changes in intracellular pH.

Making a public-private partnership work--an insider's view. Interview by John Maurice

In November 1999, Dr Amadou Diarra was appointed senior director of Bristol-Myers Squibb's Secure the Future Initiative. Launched 18 months ago, this public-private partnership is seeking, together with the governments of nine African countries, innovative ways of reducing the transmission and the impact of HIV/AIDS, especially on women and children, through interventions involving medical care, research, community outreach, and education. Diarra, who was brought up in West Africa, had previously worked for about a decade with the company's Africa division. Last November Bristol-Myers Squibb joined four other major pharmaceutical manufacturers and five intergovernmental agencies in supporting the UNAIDS initiative for Accelerating Access to HIV Care, Support and Treatment. Diarra played a significant role in laying the foundations for Bristol-Myers Squibb's commitment to both of these public-private partnerships. He shares with John Maurice his views on what it takes to make a successful partnership of this kind.

Anoxia-evoked intracellular pH and Ca2+ concentration changes in cultured postnatal rat hippocampal neurons

The ratiometric indicators 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein and Fura-2 were employed to examine, respectively, intracellular pH (pHi) and calcium ([Ca2+]i) changes evoked by anoxia in cultured postnatal rat hippocampal neurons at 37 degrees C. Under both HCO3-/CO2- and HEPES-buffered conditions, 3-, 5- or 10-min anoxia induced a triphasic change in pHi consisting of an initial fall in pHi, a subsequent rise in pHi in the continued absence of O2 and, finally, a further rise in pHi upon the return to normoxia, which recovered towards preanoxic steady-state pHi values if the duration of the anoxic insult was < or = 5 min. In parallel experiments performed on sister cultures, anoxia of 3, 5 or 10 min duration evoked rises in [Ca2+]i which, in all cases, commenced after the start of the fall in pHi, reached a peak at or just following the return to normoxia and then declined towards preanoxic resting levels. Removal of external Ca2+ markedly attenuated increases in [Ca2+]i, but failed to affect the pHi changes evoked by 5 min anoxia. The latency from the start of anoxia to the start of the increase in pHi observed during anoxia was increased by perfusion with media containing either 2 mM Na+, 20 mM glucose or 1 microM tetrodotoxin. Because each of these manoeuvres is known to delay the onset and/or attenuate the magnitude of anoxic depolarization, the results suggest that the rise in pHi observed during anoxia may be consequent upon membrane depolarization. This possibility was also suggested by the findings that Zn2+ and Cd2+, known blockers of voltage-dependent proton conductances, reduced the magnitude of the rise in pHi observed during anoxia. Under HCO3-/CO2-free conditions, reduction of external Na+ by substitution with N-methyl-D-glucamine (but not Li+) attenuated the magnitude of the postanoxic alkalinization, suggesting that increased Na+/H+ exchange activity contributes to the postanoxic rise in pHi. In support, rates of pHi recovery from internal acid loads imposed following anoxia were increased compared to control values established prior to anoxia in the same neurons. In contrast, rates of pHi recovery from acid loads imposed during anoxia were reduced, suggesting the possibility that Na+/H+ exchange is inhibited during anoxia. We conclude that the steady-state pHi response of cultured rat hippocampal neurons to transient anoxia is independent of changes in [Ca2+]i and is characterized by three phases which are determined, at least in part, by alterations in Na+/H- exchange activity and, possibly, by a proton conductance which is activated during membrane depolarization.

The public health significance of urinary schistosomiasis as a cause of morbidity in two districts in Mali

Schistosoma haematobium-related morbidity was studied in the perennial irrigation area of Office du Niger and the small reservoirs area of Plateau Dogon in Mali. Questionnaire, clinical, parasitologic, and ultrasound examination data were collected from 1,041 individuals at the baseline survey in 1991; 705 were re-examined one year after treatment. At baseline, the overall prevalence of S. haematobium infection was 55.2%; half of those infected had no clinical symptoms and 30% had pathologic lesions. Both infection and morbidity were more frequent in children than in adults, with a peak prevalence at 7-14 years of age. The rates of lesions were more than twice as high in those heavily infected as in lightly infected individuals. Reagent strip testing for microhematuria was more sensitive in detecting individuals with pathologic lesions than in detecting individuals with infection. One year after treatment with praziquantel, more than 80% of the urinary tract lesions had cleared. It is concluded that S. haematobium-related morbidity is frequent in Mali, but passive case detection for treatment would not cover a great deal of early stages of the disease; active intervention using reagent strip testing for microhematuria at the most peripheral levels would be an efficient system for morbidity control and monitoring of control operations.

Assessment of cure by detection of circulating antigens in serum and urine, following schistosomiasis mass treatment in two villages of the Office du Niger, Mali

Eight weeks after mass chemotherapy with 40 mg/kg praziquantel in two villages in Office du Niger (an irrigation area in Mali, endemic for both Schistosoma haematobium and Schistosoma mansoni) the circulating anodic (CAA) and cathodic (CCA) antigen detection assays were carried out on serum and urine samples. Both prior and post treatment highest prevalence was measured with the urine-CCA assay. Cure rates determined by antigen detection were almost half that of the egg counting methods. It was shown that the reduction in intensity should be preferentially assessed by the serum-CAA assay. Compared with egg detection, a single antigen detection assay gave a much better assessment of the impact of chemotherapy.

Circulating anodic and cathodic antigen in serum and urine of mixed Schistosoma haematobium and S. mansoni infections in Office du Niger, Mali

In Office du Niger, an area endemic for both Schistosoma haematobium and S. mansoni in Mali, circulating anodic (CAA) and cathodic (CCA) antigen detection assays were performed on pretreatment serum and urine samples from two villages, Rigandé and Siguivoucé, and compared with egg counting methods. The highest prevalence was obtained with the urine-CCA assay which also had the highest sensitivity to S. haematobium, S. mansoni or mixed infection. A single urine-CCA assay was as sensitive as repeated egg counts (one stool+two urine examinations per individual). When the different assays were tested in parallel, several combinations including assays on serum were found to be highly sensitive. As urine sampling is widely accepted, urine assays will be used for further monitoring these villages one and two years after chemotherapy.

Expression and characterization of recombinant rat parathyroid hormone-related peptide (1-141) and an amino-terminally-truncated analogue (38-141)

We have synthesized and purified recombinant parathyroid hormone related peptide (PTHrP (1-141)) and PTHrP (38-141) using an E. coli system that requires minimal purification. The cDNAs encoding PTHrP (1-141) and PTHrP (35-141) respectively were inserted into the multiple cloning site of the pTrcHis-B bacterial expression plasmid. The PTHrP encoded sequences were thereby fused at their NH2-termini to six histidine residues within the fusion protein. The recombinant plasmids were transfected into E. coli cells and PTHrP synthesis was induced by addition of 1 mM isopropyl-beta-D-thiogalactopyranoside (IPTG) at 37 degrees C. The recombinant fusion proteins were purified by binding of the histidine residues to a nickel column followed by gradient elusion and dialysis. PTHrP (1-141) was released from its fusion protein by cyanogen bromide cleavage, whereas PTHrP (38-141) was released by enzymatic digestion with enterokinase. This rapid isolation method resulted in pure PTHrP (1-141) and (38-141) as judged by SDS-polyacrylamide gel electrophoresis and NH2-terminal sequence analysis. PTHrP (1-141) stimulated cAMP accumulation and mobilized intracellular calcium ([Ca2+]i) in UMR106 osteoblast-like cells, and stimulated phosphate transport in OK/E renal cells, whereas PTHrP (38-141) was inert in these bioassays. Availability of PTHrP and its NH2-terminally truncated analogue, which lacks the sequence necessary for its hypercalcemic actions, will enable their biological activities to be examined in greater detail.

Comparison of the circulating anodic antigen detection assay and urine filtration to diagnose Schistosoma haematobium infections in Mali

The applicability of a circulating Schistosoma antigen detection assay for determining rates of infection and efficacy of chemotherapy was evaluated in Mali. Urine egg counts were compared to circulating anodic antigen enzyme-linked immunosorbent assay (CAA-ELISA) titres in serum, before and 6 weeks after treatment with a single dose of praziquantel (40 mg/kg), in 2 villages in Dogon Country, an area endemic for S. haematobium, the predominant schistosome infection in Mali. In Kassa, a village with a moderate prevalence of infection, the serological prevalence (48%) was significantly higher than the parasitological prevalence (31%). In Boro, a village with high parasitological prevalence (76%), no difference was observed between the results of both methods (prevalence by CAA-ELISA was 75%). Cure rates estimated by CAA-ELISA were lower than those determined parasitologically, suggesting that cure rates are overestimated by egg counting. The sensitivity of the CAA-ELISA was 78%. In both villages, before treatment, a positive correlation was found between the number of eggs in urine and serum CAA titres. It is concluded that, although further simplification and improvement of the sensitivity of the assay is needed, in its present ELISA format the antigen detection assay is useful for monitoring sentinel populations. Furthermore, the serum CAA assay performed adequately in a public health laboratory within an endemic country.

[The antioxidative activity of the tissues and lipids in rats of different ages]

The experiment on white Wistar rats 3-, 12- and 24 months old was carried out to study antioxidative activity in homogenates of the pancreas, adrenal glands, testes, muscles, heart and in lipids isolated from these tissues. The data were obtained in the model of thermal autooxidation of homogenates and lipids as well as during autooxidation of linethol in the presence of the samples studied. kinetics of peroxidation of tissue lipids, their effect on linethol oxidation rate and content of total lipids in the tissues were estimated. Contribution of the lipids to the total antioxidative activity of the tissue varies with age. Tissue properties of the parameters in question are observed as well as active participation of all the tissues studied in the support of the antioxidative homeostasis in the organism. Intensity of the participation depended on the age of animals.

Schistosomiasis in Dogon country, Mali: identification and prevalence of the species responsible for infection in the local community

The prevalence of schistosomiasis amongst the Dogon people in 4 villages and one school of the Bankass district of Mali was determined during 2 surveys in 1992; 1398 urine and 1199 stool samples were examined. The most common schistosome was Schistosoma haematobium, with an overall prevalence of 51.3%; S. mansoni had a prevalence of 12%. No S. intercalatum egg was seen in the stools. Biomphalaria pfeifferi and Bulinus truncatus were found in pools at the base of the Dogon cliffs; Bulinus forskalii was found in smaller numbers in brick pits. Two isolates from urine samples of children were identified as S. haematobium in the laboratory using an alpha-glycerophosphate marker, restriction enzyme analysis of ribosomal deoxyribonucleic acid (rDNA) and random amplification of polymorphic DNA. The isolates did not develop in Bulinus forskalii or B. crystallinus of the B. forskalii group. Some evidence for past hybridization of S. haematobium and S. intercalatum is provided by the enzyme and rDNA results as well as the positive Ziehl-Neelsen staining of polymorphic eggs in urine samples. The findings are discussed in relation to the published observations concerning schistosomiasis in travellers returning from this region of Mali.

Lack of ultrasonographic evidence for severe hepatosplenic morbidity in schistosomiasis mansoni in Mali

The inhabitants of four villages endemic for Schistosoma mansoni in central Mali (n = 1,106 of both sexes, age range 2-80 years) and of two nonendemic villages in another part of the country were examined parasitologically and ultrasonographically to establish the prevalence of periportal liver fibrosis (PF) and other features of hepatosplenic schistosomiasis. The prevalence of S. mansoni infection ranged from 36% to 93% in the endemic villages. A severe infection (> 400 eggs/g of stool) was found in 16% of the infected individuals. No case of grade III PF (echogenic bands usually > 10 mm in diameter around the central part and major branches of the portal vein and streak-like fibrous bands that extended into the periphery of the liver) and only eight cases of grade II PF (echogenic bands usually > 10 mm in diameter around the central part and major branches of the portal vein) were found; no other signs of severe hepatosplenic disease were encountered. However, grade I PF (echogenic bands usually > 4 mm in diameter that were best visible in the area of the portal vein bifurcation and gall bladder neck) was detected in 21% of all individuals, mainly in adults. In the nonendemic villages, the prevalence of grade I PF in adults was 9%. Generally, there was no significant correlation between the grade of PF and S. mansoni egg output. In one village with a high endemicity level, however, the prevalence of grade PF I increased with the intensity of infection. Morphometric data revealed no significant influence of S. mansoni infection on portal vein stem diameter and spleen size.(ABSTRACT TRUNCATED AT 250 WORDS)

Histamine-evoked Ca2+ oscillations in HeLa cells are sensitive to methylxanthines but insensitive to ryanodine

The relative contribution of inositol-trisphosphate(InsP3)-sensitive and InsP3-insensitive Ca2+ stores to the agonist-evoked oscillatory release of Ca2+ in HeLa cells was investigated using fura-2 cytosolic Ca2+ measurements and whole-cell recordings of Ca(2+)-activated K+ currents [K(Ca2+)]. The experimental approach chosen consisted in studying the effects on Ca2+ oscillations of a variety of pharmacological agents such as ryanodine, ruthenium red, caffeine and theophylline, which are known to affect the Ca2+ channels responsible for Ca(2+)-induced Ca2+ release (CICR) in excitable cells. The results obtained essentially indicate (a) that neither ryanodine nor ruthenium red affects the generation of periodic K(Ca2+) current pulses in whole-cell experiments, and (b) that histamine-induced Ca2+ oscillations are inhibited by caffeine and theophylline in a dose-dependent manner. However, these methylxanthines were unable, at concentrations ranging from 0.1 mM to 10 mM, either to mobilize Ca2+ from internal stores or to block the initial Ca2+ rise evoked by histamine. In addition, both methylxanthines showed at high concentrations (10-20 mM) a moderate inhibitory action on the production of InsP3 induced by histamine. This effect was not essential to the action of caffeine on the oscillatory release of Ca2+, since an inhibition by caffeine of InsP3-induced Ca2+ oscillations was still observed in whole-cell experiments where the InsP3 concentration was kept constant. The results also show (c) that the application of either caffeine or theophylline during histamine stimulation leads systematically to an increased Ca2+ sequestration in InsP3-sensitive Ca2+ pools, the effect observed with theophylline being stronger than that resulting from the application of caffeine, and finally (d) that the action of caffeine and theophylline is not related to an increase in cAMP concentration since neither forskolin (10-50 microM) nor 8-Br-cAMP (1 mM) caused an inhibition of the InsP3-induced Ca2+ oscillations. It is concluded on the basis of these results that the agonist-evoked Ca2+ oscillations in HeLa cells do not involve directly or indirectly a ryanodine-sensitive Ca(2+)-release channel with CICR properties, but rather arise from a control by Ca2+ of the InsP3 Ca(2+)-release process.