| plasmodium falciparum-malaria: resistance to chloroquine, but sensitivity to mefloquine in the gabon. a prospective in-vitro study. | a determination of the sensitivity to chloroquine and to mefloquine was carried out in malaria patients of the albert schweitzer hospital, lambarene, gabon, by using the schizont maturation test. the chloroquine testing showed in 6 of 31 cases a schizont maturation at 1.14 pmol/microliter of blood and more; this means an in-vitro resistance in 19% of the cases. the evaluation of the effective concentrations (i.e. concentrations producing the appropriate inhibition of schizont maturation) with th ... | 1984 | 6369691 |
| drug sensitivity of plasmodium falciparum in gabon. activity correlations between various antimalarials. | the sensitivity of plasmodium falciparum to chloroquine, mefloquine, quinine, halofantrine, and sulfadoxine/pyrimethamine has been investigated at lambaréné, in the gabonese rain forest, between april and september 1992. who standard micro in vitro tests were performed. of 43 isolates tested for response to chloroquine all were resistant to the drug with mean ec 50 and ec 90 values of 1.86 and 4.18 mumol/l blood, respectively, indicating the highest degree of resistance ever reported from centra ... | 1994 | 7899790 |
| comparison of micronized halofantrine with chloroquine-antibiotic combinations for treating plasmodium falciparum malaria in adults from gabon. | multidrug resistance of plasmodium falciparum is spreading throughout africa. in lambarene, gabon where chloroquine-resistant malaria is prevalent, a randomized comparative trial with three regimens for treating p. falciparum malaria in adults was performed. one hundred two patients evaluated received either a new micronized formulation of halofantrine (8 mg/kg every 6 hr in three doses) (group h) or chloroquine (25 mg/kg for a 48-hr period) plus clindamycin (5 mg/kg every 12 hr in six doses) (g ... | 1994 | 8024076 |
| malaria epidemiology in the province of moyen ogoov, gabon. | in the course of epidemiological and immunological baseline studies parasitological surveys were conducted, in 1992, in three localities situated in our near rain forest in the area of lambaréné, gabon, western central africa. anopheles gambiae s.s. and a. funestus are considered to be the main vectors of malaria. the three localities represent strata with obvious differences in the intensity of malaria transmission. the lowest parasite rates were recorded in the village around the albert-schwei ... | 1995 | 8525289 |
| atovaquone and proguanil for plasmodium falciparum malaria. | the increasing spread of multidrug-resistant plasmodium falciparum malaria emphasises the urgent need for alternative treatment regimens. the objective of the study was to establish the efficacy of a novel drug combination. we compared a combination of atovaquone and proguanil with amodiaquine in the treatment of acute uncomplicated p falciparum malaria in lambaréné, gabon. | 1996 | 8684102 |
| plasmodium falciparum: in vitro chloroquine susceptibility and allele-specific pcr detection of pfmdr1 asn86tyr polymorphism in lambarene, gabon. | plasmodium falciparum resistance to chloroquine has been described in many parts of the world particularly in africa where malaria is endemic. high levels of chloroquine resistance in our study area, lambarene-gabon, has led to the use of an alternative regimen for treatment and prevention of p. falciparum infection. in this study, we examined the in vitro chloroquine sensitivity of 15 isolates from this area and assessed the prevalence of a putative chloroquine resistance associated pfmdr1 poly ... | 1998 | 9550213 |
| follow-up of the susceptibility of plasmodium falciparum to antimalarials in gabon. | the sensitivity of plasmodium falciparum to chloroquine, mefloquine, quinine, quinidine, halofantrine, artemisinin, and sulfadoxine/pyrimethamine was investigated in lambarene, gabon in 1994. the development of in vitro susceptibility has been traced from 1983 or 1992 to 1994 for chloroquine, mefloquine, halofantrine, and quinine. standard in vitro microtests according to world health organization methodology were performed. of 33 isolates tested for susceptibility to chloroquine, 31 were resist ... | 1998 | 9598450 |
| association of the icam-1kilifi mutation with protection against severe malaria in lambaréné, gabon. | the intercellular adhesion molecule-1 (icam-1) is thought to be a receptor that mediates binding of plasmodium falciparum-infected erythrocytes. especially in vital organs, the binding of parasitized cells to the endothelium via icam-1 may lead to severe disease and death. recently, a mutation in the coding region of icam-1, termed icam-1kilifi, was described, causing a change from lys to met in the loop that interacts with rhinoviruses, lymphocytes, and parasitized red blood cells. surprisingly ... | 1999 | 10586911 |
| malaria chemoprophylaxis with tafenoquine: a randomised study. | tafenoquine is an analogue of primaquine with an improved therapeutic and safety profile. it has a long half-life and activity against liver-stage malaria parasites, so may be useful for chemoprophylaxis. in this randomised, double-blind study we assessed the efficacy and safety of tafenoquine in different doses. | 2000 | 10885356 |
| genetic diversity of plasmodium falciparum infections in one family in lambaréné. | | 2000 | 11127237 |
| declining chloroquine resistance of plasmodium falciparum in lambaréné, gabon from 1992 to 1998. | plasmodium falciparum malaria continues to threaten human populations in the tropics and travellers in endemic areas. drug resistance of the parasite is a major problem in treating this devastating disease. in a prospective trial we investigated the in vitro sensitivity of plasmodium falciparum to chloroquine, quinine and mefloquine in the albert schweitzer hospital in lambaréné, gabon every second year from 1992 to 1998. we used the standard who in vitro sensitivity assay. parasite sensitivity ... | 2001 | 11233471 |
| high prevalence of human antibodies to recombinant duffy binding-like alpha domains of the plasmodium falciparum-infected erythrocyte membrane protein 1 in semi-immune adults compared to that in nonimmune children. | we used a panel of nine fusion proteins that contain different duffy binding-like alpha (dbl-alpha) domains of plasmodium falciparum-infected erythrocyte membrane protein 1 to assess the levels of antibody activity in serum samples obtained from semi-immune or nonimmune individuals from lambaréné, gabon. recognition was measured in terms of either the prevalence or the magnitude of the response. a strong correlation between the immune status of the patients and reactivity with recombinant protei ... | 2001 | 11705939 |
| pfmdr1 alleles and response to ultralow-dose mefloquine treatment in gabonese patients. | the identification of parasite molecular markers involved in resistance to antimalarial compounds is of great interest for monitoring the development and spread of resistance in the field. polymorphisms in plasmodium falciparum multidrug resistance gene 1 (pfmdr1) have been associated with chloroquine resistance and mefloquine susceptibility. in the present study, carried out in lambaréné, gabon, we investigated the relationship between the presence of mutations at codons 86, 184, 1034, 1042, an ... | 2002 | 11751128 |
| change in plasmodium falciparum genotype during successive malaria episodes in gabonese children. | extensive polymorphism in the malaria parasite plasmodium falciparum is one of the major obstacles to controlling the disease. with the aim of analysing the dynamics of p. falciparum inoculations, we investigated the parasite genotypes of successive malaria episodes. polymerase chain reaction was performed on blood samples collected longitudinally from 31 children in lambaréné, gabon. the polymorphic regions of the merozoite surface antigens 1 and 2 were used as genetic markers. the data show th ... | 2001 | 11763432 |
| polymorphisms in the parasite genes for pfcrt and pfmdr-1 as molecular markers for chloroquine resistance in plasmodium falciparum in lambaréné, gabon. | | 2002 | 12049468 |
| new emerging plasmodium falciparum genotypes in children during the transition phase from asymptomatic parasitemia to malaria. | semi-immunity against plasmodium falciparum occurs after many infections. in areas of high malaria transmission, the prevalence of asymptomatic parasite carriers increases with age. we investigated p. falciparum genotypes in a cohort of asymptomatic carriers who were followed until they became symptomatic. blood spots on filter paper and blood smears were collected daily from 10 children in lambaréné, gabon. the parasite genotypes present on successive days were determined by a polymerase chain ... | 2002 | 12224569 |
| reassessment of the resistance of plasmodium falciparum to chloroquine in gabon: implications for the validity of tests in vitro vs. in vivo. | increasing resistance of plasmodium falciparum to antimalarial drugs presents a major risk factor for people living in endemic areas of tropical africa. in lambaréné, gabon, regular surveillance of chloroquine sensitivity of p. falciparum in vitro has been carried out since 1992 using the who standard microtest. results indicated that from 1994 onwards chloroquine resistance in vitro decreased significantly and that by 2000, about 70% of parasite isolates seemed to be sensitive to chloroquine in ... | 2002 | 12625146 |
| normal riboflavin status in malaria patients in gabon. | previous publications reported commonly the occurrence of riboflavin deficiency and a positive correlation between riboflavin status and parasitemia in patients with plasmodium falciparum malaria. in these studies, riboflavin status was determined by erythrocyte glutathione reductase activation coefficients (egracs). inherited low erythrocyte glutathione reductase activity is highly prevalent in malarial regions, however. to rule out falsely diagnosed riboflavin deficiency in affected patients, ... | 2003 | 12641409 |
| in vitro activity of quinolines against plasmodium falciparum in gabon. | the assessment of drug sensitivity of plasmodium falciparum to antimalarial drugs is of vital interest for malaria endemic regions. we conducted a follow-up study to monitor the in vitro activity of the most commonly used quinolines against fresh p. falciparum isolates in lambaréné, gabon by measuring schizont maturation inhibition in 2002. mean 50% effective concentration levels for chloroquine, quinine, and mefloquine were 5.5micromol/l blood, 286nmol/l blood medium mixture (bmm), and 1.1micro ... | 2004 | 14739023 |
| submicroscopic plasmodium falciparum infections and multiplicity of infection in matched peripheral, placental and umbilical cord blood samples from gabonese women. | summary in malaria-endemic regions, pregnant women are more susceptible to malarial infections than non-pregnant women. the main objective of this study, which was conducted in the malaria hyperendemic town of lambaréné (gabon, central africa), was to characterize plasmodium falciparum infections in peripheral, placental and cord blood from women of different gravidities with submicroscopic infections. using the p. falciparum merozoite surface protein 2 (msp 2)* gene as a polymorphic marker in p ... | 2004 | 15361107 |
| clinical and parasitological characteristics of puerperal malaria. | women with semi-immunity to malaria who live in regions where the disease is endemic are at increased risk for more frequent and severe episodes of malaria during pregnancy. recent findings indicate that this increased risk might persist beyond delivery, but the underlying mechanisms for this change in risk are poorly understood. | 2005 | 15717279 |
| effectiveness of quinine monotherapy for the treatment of plasmodium falciparum infection in pregnant women in lambaréné, gabon. | pregnant women participating in a longitudinal immuno-epidemiologic survey in lambaréné, gabon, and presenting with plasmodium falciparum parasitemia at monthly blood smear examinations were offered treatment with oral 7-day quinine monotherapy according to national health guidelines. a total of 50 pregnant women were offered 7-day oral quinine sulfate 10 mg/kg thrice daily. clinical examinations and laboratory tests were performed on days 28 and 56 to assess the effectiveness of this standard r ... | 2005 | 16103585 |
| amplification of plasmodium falciparum multidrug resistance gene 1 in isolates from gabon. | the study of molecular markers of drug resistance is particularly important in surveillance studies of drugs, such as mefloquine, that still retain efficacy in sub-saharan africa yet have encountered resistance elsewhere. in a recent study in thailand, we identified amplification of the plasmodium falciparum multidrug resistance gene 1 (pfmdr1) as being the most important predictor of in vitro drug resistance and in vivo failure of mefloquine monotherapy. here we report amplification of pfmdr1 i ... | 2005 | 16235185 |
| no variation in the prevalence of point mutations in the pfcrt and pfmdr1 genes in isolates from gabonese patients with uncomplicated or severe plasmodium falciparum malaria. | in lambaréné (gabon), where a high level of plasmodium falciparum resistance to chloroquine has been reported, we assessed the relationship between polymorphisms in the p. falciparum chloroquine resistance transporter (pfcrt) and multidrug resistance-1 (pfmdr1) genes and the clinical severity of malaria. ninety-one and 60 p. falciparum isolates from children with uncomplicated or severe malaria were collected in 1996 and 2002, respectively. single nucleotide mutations at codon 76 in the pfcrt ge ... | 2007 | 17096149 |
| short course of quinine plus a single dose of sulfadoxine/pyrimethamine for plasmodium falciparum malaria. | quinine remains the treatment of choice in hospitalized malaria cases; however, adverse reactions and the long treatment duration of 7 days often hamper its adequate use. shortening the treatment by adding sulfadoxine/pyrimethamine may enhance compliance and reduce side effects. we aimed to assess the efficacy of a 3-day course of quinine plus a single dose of sulfadoxine/pyrimethamine for the treatment of non-severe hospitalized malaria cases in lambaréné, gabon. | 2006 | 17136336 |
| ibuprofen does not affect levels of tumor necrosis factor alpha and soluble tumor necrosis factor receptor types i and ii in gabonese children with uncomplicated plasmodium falciparum malaria. | we assessed the ability of ibuprofen to modulate tumor necrosis factor alpha (tnf-alpha), soluble tumor necrosis factor receptor type i (stnfr-i), and soluble tumor necrosis factor receptor type ii (stnfr-ii) responses during the treatment of fever in uncomplicated plasmodium falciparum malaria, in a placebo-controlled, randomized, double-blind study of 50 pediatric patients in lambaréné, gabon. treatment of the malaria involved the patients receiving intravenous quinine (12 mg/kg of quinine dih ... | 2007 | 17964975 |
| high prevalence of asymptomatic plasmodium falciparum infection in gabonese adults. | plasmodium falciparum, the most common malarial parasite in sub-saharan africa, accounts for a high number of deaths in children less than five years of age. in malaria-endemic countries with stable transmission, semi-immunity is usually acquired after childhood. for adults, severe malaria is rare. infected adults have either uncomplicated malaria or asymptomatic parasitemia. during a period of one year, we screened 497 afebrile males to investigate the prevalence of asymptomatic p. falciparum p ... | 2007 | 17984357 |
| differences in presentation of severe malaria in urban and rural gabon. | there are rare comparative studies of the clinical and laboratory features of severe and moderate malaria, including predictors of poor outcome, in rural and urban areas for regions of high malaria transmission. we therefore studied 2,235 children hospitalized for malaria in a rural (lambaréné) and an urban (libreville) area in gabon between january 2001 and december 2002. from children screened, 33% and 48% were hospitalized for malaria in libreville and lambaréné, respectively (p < 0.001). two ... | 2007 | 18165514 |
| interleukin-21 is associated with igg1 and igg3 antibodies to erythrocyte-binding antigen-175 peptide 4 of plasmodium falciparum in gabonese children with acute falciparum malaria. | interleukin-21 (il-21) is a newly described, typical, four-helix cytokine showing significant homology with il-2, il-4 and il-15. it regulates igg1 production and co-operates with il-4 in the production of multiple antibody classes in vivo. igg1 and igg3 are critically involved in the development of clinical immunity to plasmodium falciparum malaria. however, the mechanisms driving class-switch recombination towards these specific isotypes remain to be elucidated. seventy-three children with p. ... | 2008 | 18299268 |
| comprehensive study of proteasome inhibitors against plasmodium falciparum laboratory strains and field isolates from gabon. | the emergence and spread of plasmodium falciparum resistance to almost all available antimalarial drugs necessitates the search for new chemotherapeutic compounds. the ubiquitin/proteasome system plays a major role in overall protein turnover, especially in fast dividing eukaryotic cells including plasmodia. previous studies show that the 20s proteasome is expressed and catalytically active in plasmodia and treatment with proteasome inhibitors arrests parasite growth. this is the first comprehen ... | 2008 | 18816382 |
| automated detection of haemozoin-containing monocytes for the diagnosis of malaria in microscopically negative cases during pregnancy. | plasmodium falciparum sequesters in the placenta. cell-dyn automated flow cytometric haematology analysers have the capacity to detect haemozoin-containing circulating leukocytes during routine fbc analysis. in lambaréné, gabon, 685 fbcs of pregnant women were analysed, yielding 86.8% sensitivity and 78.5% specificity compared to microscopy. in a subset of 37 cell-dyn positive but microscopy negative samples, pcr detected five positive cases. this methodology may serve as an adjunct rapid diagno ... | 2009 | 19121281 |
| in vitro activity of pyronaridine against plasmodium falciparum and comparative evaluation of anti-malarial drug susceptibility assays. | pyronaridine, a mannich base anti-malarial with high efficacy against drug resistant plasmodium falciparum, is currently evaluated as a fixed dose combination with artesunate for the treatment of uncomplicated malaria. in this study, the in vitro activity of pyronaridine against clinical isolates of p. falciparum from lambaréné, gabon, was assessed in order to obtain baseline data on its activity prior to its future use in routine therapy. moreover, follow-up assessment on the in vitro activity ... | 2009 | 19389221 |
| the lambaréné organ dysfunction score (lods) is a simple clinical predictor of fatal malaria in african children. | plasmodium falciparum malaria accounts for >1 million deaths annually, mostly among young children in sub-saharan africa. identifying those individuals who are likely to die is crucial. several factors have been independently associated with death. because malaria is a systemic disease, a quantitative score combining such risk factors may be superior. | 2009 | 19911989 |
| in vitro activity of tigecycline in plasmodium falciparum culture-adapted strains and clinical isolates from gabon. | emerging drug resistance in plasmodium falciparum and its rapid spread in endemic countries have made the quest for new antimalarials a research priority. tetracycline and its derivatives are well-established compounds for combination with faster-acting drugs in the current practice of malaria treatment. tigecycline is the first marketed derivative of a new class of tetracycline antibiotics. its altered structure leads to enhanced activity against bacteria and may also be associated with improve ... | 2010 | 20227854 |
| epidemiology of parasitic co-infections during pregnancy in lambaréné, gabon. | summary objectives: to evaluate the epidemiologic data of parasitic infections and co-infections in pregnant women in lambaréné, gabon. | 2010 | 20636299 |
| safety and immunogenicity of the malaria vaccine candidate gmz2 in malaria-exposed, adult individuals from lambaréné, gabon. | malaria is still one of the major public health threats in sub-saharan africa. an effective vaccine could be a sustainable control measure that can be integrated into existing health infrastructures. the malaria vaccine candidate gmz2 is a recombinant fusion protein of conserved parts of plasmodium falciparum glutamate rich protein and merozoite surface protein 3 adjuvanted with aluminium hydroxide. gmz2 is immunogenic and well tolerated in malaria-naive adults from germany. to assess safety and ... | 2010 | 20696154 |
| high prevalence of dhfr triple mutant and correlation with high rates of sulphadoxine-pyrimethamine treatment failures in vivo in gabonese children. | abstract: background: drug resistance contributes to the global malaria burden. plasmodium falciparum dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) polymorphisms confer resistance to sulphadoxine-pyrimethamine (sp). methods: the study assessed the frequency of sp resistance-conferring polymorphisms in plasmodium falciparum-positive samples from two clinical studies in lambarene. their role on treatment responses and transmission potential was studied in an efficacy open-labe ... | 2011 | 21569596 |
| assessment of led fluorescence microscopy for the diagnosis of plasmodium falciparum infections in gabon. | abstract: background: rapid and accurate diagnosis of malaria is central to clinical management and the prevention of drug-overuse, which may lead to resistance development, toxicity and economic losses. so far, light microscopy (lm) of giemsa-stained thick blood smears is the gold standard. under optimal conditions the procedure is fast and reliable; nevertheless a gain in speed would be a great advantage. rapid diagnosis tests are an alternative, although they cost more and give qualitative in ... | 2011 | 21767366 |