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

Two field trials to detect chloroquine-resistant malaria were conducted according to WHO recommendations in a malaria free area near Rangoon. Peripheral blood smears were examined for asexual forms of P. falciparum on day one through to day seven, on day 14, 21, and 28 after a standard dose of 1500 mg. of chloroquine base. Haskins test to detect chloroquine in urine was done on all cases and plasma chloroquine levels were measured in some. Out of 105 patients tested RI resistance was detected in 66, RII in 19 and RIII in three. Subsequent trials with other anti-malarial drugs indicated that the chloroquine-resistant P. falciparum were also resistant to one day therapy with pyrimethamine 50 mg. or sulphamethoxypyridazine 1 G given singly; and resistant to one day therapy with combinations of pyrimethamine 50 mg. plus sulphamethoxy pyridazine 1 G, pyrimethamine 13 mg. plus dapsone 100 mg., and trimethoprim 320 mg. plus sulphamethoxazole 1600 mg. All those tested were sensitive to quinine sulphate, 0-6 G given three times a day for 10 days, and were also sensitive to one day therapy with combinations of trimethoprim 500 mg. plus sulphalene 1 G, and pyrimethamine 50 mg. plus sulphamethoxine 1 G. Pyrimethamine 12-5 mg. plus dapsone 100 mg. in weekly doses was shown to be an effective chemoprophylaxis. Quinine was tested on 38 subjects while other drug schedule were tested on six to eight subjects.
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PMID:Chloroquine-resistant malaria in Burma. 12 38

There is need for effective chemoprophylaxis against chloroquine-resistant falciparum malaria, and for a safe and effective drug to be readily available for the treatment of that condition. Experience with the cases cited in this study indicates that Fansidar should be made available for treatment and it is suggested that Maloprim be made available as a prophylactic agent.
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PMID:Chloroquine-resistant falciparum malaria from Papua New Guinea and its implications for Australia. 32 Apr 35

It is known that malaria parasites are inhibited by sulfonamides and antifolate compounds, require 4-aminobenzoic acid for growth, and respond only partly to intact folic and folinic acids. Biochemical data obtained during the last decade on the synthesis of nucleic acid precursors and on folate enzymes in malaria support the hypothesis that malaria parasites are similar to microorganisms that synthesize folate cofactors de novo. Sulfa drugs inhibit plasmodial dihydropteroate synthase (EC 2.5.1.15). Pyrimethamine and many other antifolate compounds bind to tetrahydrofolate dehydrogenase (EC 1.5.1.3) of the parasite more tightly than to the host enzyme. However, the metabolic consequences of the depletion of folate cofactors as a result of drug inhibition are not yet known. Other areas to be studied are the origin of the pteridine moiety of folates, the addition of glutamate(s) in folate cofactor biosynthesis, the means by which intact, exogenous folates affect malarial growth, and demonstration of the enzymes and reactions involving N(5)-methyl tetrahydrofolate.
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PMID:Folate metabolism in malaria. 33 84

The effect of pyrimethamine and the combination of pyrimethamine-sulfadoxine (Fansidar) upon the termination of the acute attack of vivax malaria was studied in Thailand. Pyrimethamine was found to be ineffective, providing clearance of parasitaemia in only two of six patients by the end of seven days following treatment. The combination, administered in a two-tablet single dose (sulfadoxine 1 gm, pyrimethamine 50 mg) eliminated parasitaemia in only six of ten patients within seven days. Three tablets (sulfadoxine 1 . 5 gm, pyrimethamine 75 mg) given to 11 patients, provided clearance of parasitaemia in all within seven days; however, mean parasite and fever clearance times in this group were prolonged at 90 and 50 hours respectively. Chloroquine remains the drug of choice for the termination of the acute attack of vivax malaria. Subsequent primaquine is necessary for the prevention of relapse.
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PMID:Treatment of vivax malaria with sulfadoxine-pyrimethamine and with pyrimethamine alone. 37 85

Patients with naturally acquired chloroquine-resistant falciparum malaria were studied in Thailand. The fixed combination of pyrimethamine 75 mg and sulfadoxine 1,500 mg (adult dose) cured 85% of patients with an average pretreatment parasite count of 60,000 per mm(3). The fixed combination of pyrimethamine 50 mg and 800 mg diformyldapsone (DFD) cured 43% of patients with an average pretreatment parasite count of only 17,000 per mm(3). The difference in cure rates was statistically significant (p less than 0.01). Pyrimethamine alone was ineffective. Pyrimethamine-DFD, in the dose tested, was not sufficiently active for the treatment of established infections. Pyrimethamine-sulfadoxine did produce an acceptable cure rate but clinical improvement was often slow. We do not recommend that pyrimethamine-sulfadoxine be administered alone. Optimal results are obtained when a short course of quinine (2 to 6 days) is given until parasitemia has been eliminated, then a dose of pyrimethamine-sulfadoxine to assist in the radical cure of the falciparum infection. A modification to the W.H.O. classification is suggested. An RIII response (early treatment failure) is diagnosed if the patient's clinical condition and/or parsite density worsens within a few hours after administration of the test regimen; distinct improvement occurring within a few hours of the subsequent initiation of an intravenous infusion of quinine confirms the diagnosis of an RIII response. The RII response has been defined as marked reduction, but not clearance of asexual parasitemia. It is suggested that an RII response may be diagnosed before 7 days have elapsed.
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PMID:Single-dose therapy of Falciparum malaria using pyrimethamine in combination with diformyldapsone or sulfadoxine. 76 72

The duration of action of the drug Antemal, a combination of Pyrimethamine and Sulfametopyrazine, was eveluated in Bobo-Dioulasso, Upper Volta, West Africa, and endemic zone for Plasmodium falciparum malaria. The study was held during the season of maximum malaria transmission. 79 persons presenting with an acute attack of malaria were studied; 37 persons received a single dose of chloroquine sulfate (Nivaquine), at a dose of 15 mg./kg.; 42 persons received a single dose of Antemal at a dose of one tablet (75 mg. of Pyrimethamine and 25 mg. of Sulfametopyrazine) per 10 kg. Clinical and parasitological studies of all subjects occurred on days one, two, three, 10, 17, 24 and 31. Only one of 37 (2.7%) subjects on Antemal had a reappearance of trophozoites, occurring on day 17. Eight of 42 (19.0%) patients taking nivaquine had reappearance of trophozoites, observed between day 23 and 31. Gametocytes were observed in eight of 37 (21.6 %) persons on Antemal and in only one of 42 (2.3 %) persons on Nivaquine. These observations suggest an extended duration of protection from Antemal in semi-immune individuals. Nivaquine appeared as a potent inhibitor of gametocytogenesis.
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PMID:[Duration of action of the pyrimethamine-sulfametopyrazine combination in a Plasmodium falciparum endemic zone]. 110 Feb 87

In recent trials in The Gambia, mass chemoprophylaxis with Maloprim administered over several years by primary health care workers to children aged 3-59 months has reduced both mortality and morbidity without inducing impairment of natural immunity or significant development of drug resistance. Taking expenditure of both time and money, by both public authorities and village volunteers, into account, the costs and the cost effectiveness of such mass chemoprophylaxis are estimated here. The cost per child protected per season was (1990 US) $2.84; the cost per childhood death averted was $143. Both costs compare favourably with those of permethrin bed net impregnation. So in some circumstances where malaria is holoendemic, control of childhood malaria by chemoprophylaxis may be more economically efficient than provision of impregnated bed nets.
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PMID:The cost-effectiveness of chemoprophylaxis with Maloprim administered by primary health care workers in preventing death from malaria amongst rural Gambian children aged less than five years old. 128 3

A placebo-controlled chemoprophylaxis trial was carried out in 1980 in 318 semi-immune school children in the Madang area of Papua New Guinea, where there was a high prevalence of strains of Plasmodium falciparum resistant to 4-aminoquinolines. Since prophylaxis with amodiaquine at 5 mg/kg weekly had failed, amodiaquine at a dose of 10mg/kg weekly and Maloprim (half a tablet or one tablet depending on body weight, which gave ranges of dapsone of 1.7-3.3mg/kg and pyrimethamine 0.2-0.4 mg/kg) weekly were tried. Neither regimen was completely successful in preventing parasitaemia, though after 13 weeks of prophylaxis the slide positivity rate was 16% for the amodiaquine group and 2% for the Maloprim group, which was in each case significantly lower than the normal baseline rate in the controls of 42%. Amodiaquine was completely successful in suppressing Plasmodium vivax infections. Breakthrough parasitaemia occurred, with either P. falciparum or P. vivax, in 5% of subjects on Maloprim at some time during the 13-week period of prophylaxis. Significantly more children in both the amodiaquine and Maloprim groups than in the placebo group showed a reduction in spleen size. All groups showed an unexplained fall in haemoglobin level over the study period but the fall was significantly less in both the prophylaxis groups. There was no adverse effect on white cell counts by either drug regimen. Chemoprophylaxis as a component of an integrated malaria control program should not be overlooked, provided that compliance can be maintained. However, in this particular case the principal purpose of the study had been to evaluate the proposed chemoprophylactic regimens in school children before embarking on an intervention study in young children. As a result of this study it was decided not to go ahead with the chemoprophylactic intervention in young children but to adopt an approach based on early presumptive treatment.
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PMID:Chemoprophylaxis against malaria in Papua New Guinea: a trial of amodiaquine and a combination of dapsone and pyrimethamine. 134 Oct 89

An Australian expatriate on regular weekly antimalarial prophylaxis with chloroquine base and Maloprim developed symptomatic Plasmodium vivax infection which failed to respond adequately to 600 mg of chloroquine base. More ominously, a resident of the Highlands region of Papua New Guinea contracted vivax malaria which failed to be cleared by 2400 mg chloroquine base administered over 4 d. Both patients had achieved appropriate blood and plasma concentrations of chloroquine after treatment. Chloroquine-resistant P. vivax is now a clinical fact in Papua New Guinea.
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PMID:Chloroquine-resistant Plasmodium vivax in Papua New Guinea. 144 Jul 63

Over 3 years, researchers randomly assigned more than 1775 pregnant women (many in their 3rd trimester of pregnancy) from 41 villages near Farafenni, The Gambia, to receive either Maloprim (malaria chemoprophylaxis of pyrimethamine and dapsone) or a placebo to determine Maloprim's effects on birth weight and child survival. All births occurred at home. Field workers went to each home as soon as possible after delivery to weigh the newborns. The relative risks for neonatal and infant mortality were 23 for infants weighing less than 2000 gms and 12 for those who weighed at least 2500 gms. While they were 2.1 and 0.8, respectively, for infants weighing between 2000 and 2500 gms. 33.3% of low birth weight infants of primigravidae died compared with 19% of those of multigravidae. Taking Maloprim during pregnancy reduced infant mortality by 18% for infants of primigravidae and only 4% for infants of multigravidae. It reduced neonatal deaths by 42% for infants of primigravidae and by just 6% for infants of multigravidae. These results suggested that health workers should distribute antimalarial medicine to all primigravidae. Chemoprophylaxis along with other malaria control efforts, such as insecticide impregnated bed nets or a malaria vaccine, would protect mothers and their infants.
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PMID:Malaria chemoprophylaxis, birth weight and child survival. 147 10


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