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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This clinical trial compared parasitological efficacy, levels of in vivo resistance and side effects of oral chloroquine 25 mg/Kg and 50 mg/Kg in 3 days treatment in Plasmodium falciparum malaria with an extended followed-up of 30 days. The study enrolled 58 patients in the 25 mg/Kg group and 66 in the 50 mg/Kg group. All eligible subjects were over 14 years of age and came from Amazon Basin and Central Brazil during the period of August 1989 to April 1991. The cure rate in the 50 mg/Kg group was 89.4% on day 7 and 71.2% on day 14 compared to 44.8% and 24.1% in the 25 mg/Kg group. 74.1% of the patients in the 25 mg/Kg group and 48.4% of the patients in the 50 mg/Kg group had detectable parasitaemia at the day 30. However, there was a decrease of the geometric mean parasite density in both groups specially in the 50 mg/Kg group. There was 24.1% of RIII and 13.8% of RII in the 25 mg/Kg group. Side effects were found to be minimum in both groups. The present data support that there was a high level resistance to chloroquine in both groups, and the high dose regimen only delayed the development of resistance and its administration should not be recommended as first choice in malaria P. falciparum therapy in Brazil.
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PMID:A randomized clinical trial with high dose of chloroquine for treatment of Plasmodium falciparum malaria in Brazil. 134 12

In view of the recent demonstration that antibodies that are protective against Plasmodium falciparum malaria may act in collaboration with blood monocytes, we have investigated the isotype content of sera from individuals with defined clinical states of resistance or susceptibility to malaria. Profound differences in the distribution of each Ig subclass and particularly in the ratio of cytophilic versus noncytophilic antibodies were found. In protected subjects, two cytophilic isotypes, IgG1 and IgG3 were found to predominate. In non-protected subjects, i.e. children and primary attack adults, three different situations were encountered: a) an imbalance in which IgG2, a non-cytophilic class, predominated (mostly seen in primary attacks); b) an imbalance in which mostly IgM antibodies predominated (a frequent event in children) or c) less frequently, an overall low level of antimalarial antibodies. Of 33 non immune subjects studied all, except one, had one of the above defects. The function of total Ig presenting such an isotype imbalance was studied in vitro in Antibody-Dependent-Cellular-Inhibition assays. Not only did IgG from protected subjects cooperate efficiently with blood monocytes, whilst IgG from non-protected groups did not, but moreover the latter inhibit the in vitro effect of the former: in competition assays whole IgG from primary attack cases with increased IgG2 content, competed with IgG from immune adults, thus suggesting that non-protected subjects had antibodies to epitopes critical for protection, but that these antibodies are non functional.
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PMID:Antibodies in falciparum malaria: what matters most, quantity or quality? 134 95

Due to current spreading of chemoresistant strains of Plasmodium falciparum malaria control must incorporate vector control programmes. Due to well known constraints house sprayings cannot be performed as before. Personal protection can be developed and a large scale use of insecticide treated bed-nets appeared to be very useful to reduce man-vector contact in Asia, South America and West and East Africa. No trial has been done in forest Central Africa where transmission is permanent. We performed such a trial in the southern part of Cameroon (using deltamethrin, at 25 mg/m2) and obtained similar data to those observed in The Gambia, Burkina Faso and Tanzania with a noteworthy reduction of both transmission and high parasitaemia of P. falciparum (respectively 78% and 75%) meaning a drop of malaria morbidity.
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PMID:Efficacy of insecticide impregnated bed-nets to control malaria in a rural forested area in southern Cameroon. 134 14

Plasmodium falciparum malaria in Thailand is resistant to available antimalarial drugs, which necessitates the search for alternative drugs. In a clinical trial mefloquine 1250 mg in divided doses was compared with oral artemether at 700 mg total dose given over 5 days in acute uncomplicated falciparum malaria. 46 adult men, aged 15-50 years and weighing 45-65 kg, with acute uncomplicated falciparum malaria, no history of liver or kidney diseases, and not history of tasking antimalarials for this episode of illness were recruited at the Bangkok Hospitak for Tropical Diseases. 12 were treated with mefloquine and 34 with oral artemether. Hospital follow-up was 28 days for the artemether group and 42 days for the mefloquine group. Parasites did not clear from the blood of 2 patients in the mefloquine group, although there was a decrease in parasitemia. The other 10 patients in the mefloquine group has a good initial response with mean parasite clearance times and fever clearance times of 64 and 27 hours respectively. Oral artemether gave a significantly faster parasite clearance time than mefloquine (30 vs. 64 hours), and a significantly better cure rate (97 vs. 64%) with fewer episodes of dizziness and vomiting. Oral artemether at 700 mg given over 5 days is effective and well tolerated. The cure rate with this regimen is higher than that reported with 600 mg intramuscular artemether given over 5 days. Mefloquine 1250 mg has a cure rate of 80-84% but it produces side effects such as vomiting. The treatment with artemether should last at least 5 days with a dose above 600 mg for a cure rate approaching 100%. This treatment is still likely to be more acceptable to patients than the combination regimen of quinine plus tetracycline for 7 days. These findings suggest that neither artemether nor mefloquine is effective against the intrahepatic stage of Plasmodium vivax. Primaquine is the choice of drug for radical cure.
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PMID:Comparison of oral artemether and mefloquine in acute uncomplicated falciparum malaria. 135 18

Desferrioxamine B (DFO, Desferal), an iron chelator, was earlier shown to be active against Plasmodium falciparum in vitro and in vivo. The present open pilot study served to assess its clinical tolerability and efficacy in human malaria under hospital conditions. Continuous intravenous DFO was administered to 28 Thai males at a dose of 100 mg/kg over 24 h for 3 consecutive days. No other antimalarial therapy was administered unless recrudescence had occurred. The first 14 patients had symptomatic Plasmodium vivax (P.v.) malaria, while the other 14 patients were suffering from uncomplicated Plasmodium falciparum malaria (P.f.). Both groups were treated in Bangkok, where malaria transmission does not take place, and followed up, on the ward, for 3 weeks (P.v. group) or 4 weeks (P.f. group) after the start of therapy. In both groups DFO reduced the parasitaemia to zero within 106 and 57 h respectively. The fever clearance time was 55 and 60 h, respectively. The overall tolerability of DFO was good but 4 P.v. and 5 P.f. patients had transient visual blurring. Recrudescences were observed on average 15, respectively 10 days after the start of therapy. Only 2 P.v. patients and none of the P.f. patients remained free of recrudescences during the observation period. There was no apparent gametocytocidal effect of DFO on P.f.
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PMID:Plasmodicidal effect of desferrioxamine B in human vivax or falciparum malaria from Thailand. 135 61

Plasmodium falciparum malaria parasites modify the human erythrocytes in which they grow so that some parasitized erythrocytes (PE) can cytoadhere (C+) to host vascular endothelial cells or adhere in rosettes (R+) to uninfected erythrocytes. These C+ and R+ adherence properties of PE appear to mediate much of the pathogenesis of severe malaria infections, in part by blocking blood flow in microvessels. From one parasite strain, PE were selected in vitro for C+ R+ or C+ R- adherence properties and examined in model adherence assays. The C+ R+ PE cytoadhered poorly to C32 melanoma cells or to immobilized CD36 in a settled-cell assay when uninfected human erythrocytes were present and formed rosettes with PE. C+ R- PE adhered well in the same assays. However, C+ R+ PE adhered very well, even better than C+ R- PE, when the rosettes were disrupted and the C+ R+ PE were purified. Adding back rabbit erythrocytes, which do not form rosettes with C+ R+ PE, had simply a dilutional effect. The ability of rosettes to interfere with the detection of adherence must be dealt with in all future assays of malarial PE adherence. Individual PE were observed attached simultaneously to C32 cells and to a few erythrocytes, suggesting that C+ and R+ adherence properties are coexpressed on the same PE. Coexpression of these adherence properties on the same PE may have pathological importance in vivo, where passage of rosettes through capillaries may shear uninfected erythrocytes from rosetted PE and allow direct PE attachment to postcapillary venule walls before rosettes reform.
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PMID:Plasmodium falciparum-infected erythrocytes do not adhere well to C32 melanoma cells or CD36 unless rosettes with uninfected erythrocytes are first disrupted. 137 71

Among 300 cases of Plasmodium falciparum malaria attacks explored in Gabon, the proportion of homozygous (SS) or heterozygous (AS) sickle-cell patients was 6.2 percent in 206 ordinary attacks and 3.2 percent in 94 cerebral malaria attacks, and 23.2 percent in the general population. On the other hand, asymptomatic carriage, as detected in 98 children by thin blood films in school screening, was as frequent in the SS or AS infantile population as in the general population. These data show that haemoglobin S protects effectively, although not entirely, against severe attacks of P. falciparum malaria. The incidence of anaemia and vaso-obstructive crisis in malaria-infested sickle-cell patients suggests that subclinical carriage of haematozoa may worsen the course of sickle-cell disease, and this must be taken into account when planning treatment.
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PMID:[Malaria and hemoglobin S: interactions in African children]. 138 31

In mice, immune responses to subunits of defined malaria antigens are regulated by genes mapping within the MHC and it has been suggested that such genetic restriction will be a major obstacle in the development of a human malaria vaccine. The relationship between class II human leukocyte antigen (HLA) genes and immune recognition of three candidate antigens for a vaccine against Plasmodium falciparum malaria has been investigated in a human population living in a malaria endemic area of West Africa. The study population was shown to be extremely heterogeneous for HLA class II alleles and marked differences in allelic frequency were detected between members of different ethnic groups. One class II DQA-DQB combination (serological specificity DQw2) was particularly common among members of the Fula ethnic group. This haplotype was significantly associated with higher than average levels of antibody to a peptide epitope, (EENV)6, of the malaria antigen Pf155/RESA. There was little evidence of association between HLA class II genotype and cellular proliferative or interferon gamma responses to the antigens tested. Overall, the number of significant associations between immune responses and specific HLA class II haplotypes was greater than would be expected by chance but less than would be expected if class II-dependent genetic restriction were a major factor governing human immune responses to malaria antigens. Thus, although some qualitative variation in the immune response to vaccine antigens may occur in ethnically different target populations, widespread HLA-associated nonresponsiveness to a multivalent subunit malaria vaccine is unlikely.
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PMID:MHC and malaria: the relationship between HLA class II alleles and immune responses to Plasmodium falciparum. 139 Apr 36

All 110 patients seen in North East Scotland after contracting malaria from foreign travel were treated in the Regional Infection Unit in Aberdeen. Those patients managed there from January 1980 to March 1991 are described. There were 54 episodes of Plasmodium falciparum malaria (49%) and 26 episodes (23%) of Plasmodium vivax malaria. The remainder had either mixed infection or were diagnosed as malaria on high clinical probability. The majority of the patients were male (80%) and under 40 years of age (84%). Most patients were either caucasians born in the UK (69%) or native Africans (23%) who were students recently arrived for further education or who had returned from visiting their country of origin for summer holidays. The British residents acquired infection either while on oil related business in West or Central Africa (46%) or after travelling on holiday (30%). The peak incidence of presentation was August and September. 93.5% of patients with falciparum malaria had returned or originated from Africa. 42% with vivax malaria had visited Africa and 27% Papua New Guinea. 70% had been prescribed antimalarial prophylaxis but less than half of these took their medication correctly. The majority of patients with falciparum malaria presented within two weeks of arrival in Britain while patients with vivax malaria presented at varying (but generally longer) intervals, 42% being diagnosed more than three months after exposure. Falciparum infection was more severe although there have been no deaths in the unit from malaria. Our experience seemed of interest and worth reporting because of the number of patients whose infection reflected travel related to the off shore oil industry, which is centred in Aberdeen.
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PMID:Malaria in Aberdeen: an audit of 110 patients admitted between 1980-1991. 141 77

A case-control study was carried out at a community hospital in eastern Thailand in order to study the association between haemoglobin E and Plasmodium falciparum malaria; 271 P. falciparum cases and 271 controls were enrolled. After adjusting for age, sex, time since last malaria attack, history of mosquito net use, and history of fava bean consumption in the previous month, neither heterozygous nor homozygous haemoglobin E provided significant protection against P. falciparum infection, with odds ratios (OR) = 0.91 (95% confidence limits = 0.61, 1.36) and 0.78 (0.34, 1.82) respectively when compared to persons with haemoglobin A who were not consumers of fava beans. However, haemoglobin E carriers who ate fava beans were significantly protected against P. falciparum malaria with OR = 0.26 (0.09, 0.76) and OR = 0.001 (0.00, 1120.59) for subjects with heterozygous and homozygous haemoglobin E, respectively. The study suggests a possible synergistic protective effect of haemoglobin E on the risk of P. falciparum malaria in subjects who have consumed fava beans.
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PMID:Haemoglobin-E in the presence of oxidative substances from fava bean may be protective against Plasmodium falciparum malaria. 141 43


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