Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In view of the fact that increased resistance to drugs by malaria parasites in some parts of the world may lead to increasing use of a combination of primaquine with chloroquine for chemotherapy, studies were made on the severity of the haemolytic anaemia induced by 45 mg primaquine in American Negroes with glucose-6-phosphate dehydrogenase deficiency. It was found that twice-weekly administration of primaquine induced more haemolysis than once-weekly administration, and that administration once weekly for 4 weeks and twice weekly thereafter resulted in a degree of anaemia falling between those produced by the other regimens. Anaemia was not induced in controls with no G6PD deficiency. One volunteer developed an intercurrent infection that was treated with salicylates; his haemolysis was markedly intensified, but whether by the infection, the salicylates or both could not be determined.In a conjoint study, the administration of six malaria-suppressive drugs had no detectable effect on the activities of several erythrocyte enzymes or on the levels of adenosine monophosphate, diphosphate or triphosphate.
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PMID:The haemolytic effect of various regimens of primaquine with chloroquine in American Negroes with G6PD deficiency and the lack of an effect of various antimalarial suppressive agents on erythrocyte metabolism. 486 52

Erythrocyte mosaicism occurs in females heterozygous for glucose-6-phosphate dehydrogenase deficiency. In blood from female children with acute Plasmodium falciparum malaria the parasite rate was 2 to 80 times higher in normal than in deficient erythrocytes. This may be the mechanism whereby the gene for glucose-6-phosphate dehydrogenase deficiency confers selective advantage against malaria to heterozygous females, and thus may have attained the polymorphic frequency occurring in populations living in areas with endemic malaria.
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PMID:Glucose-6-phosphate dehydrogenase deficient red cells: resistance to infection by malarial parasites. 488 47

The authors report data on the genetic distribution of thalassaemia and of glucose-6-phosphate dehydrogenase deficiency in the populations of certain Sardinian villages, many of which are not only of great antiquity but have maintained isolation for very long periods and therefore possess the following three requirements for suitability for investigation of the possible interrelationships among malaria, thalassaemia and G-6-PD deficiency: a reasonable degree of ethnic homogeneity, availability of reliable demographic data, and availability of malaria-free populations of adequate size and of ethnic background and genetic isolation similar to those of the malarial populations.Investigations including more than 6000 observations in 52 villages demonstrated a positive correlation between the incidences of thalassaemia and G-6-PD deficiency. It is suggested that the genotype that carries thalassaemia and/or the enzyme deficiency may have a high adaptive value in a malarial environment.It is concluded that there is a need further to investigate human genetic structure and the biological fitness of the principal genotype combinations in both existing environments and those that will result from continued cultural evolution.
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PMID:Population genetics of haemoglobin variants, thalassaemia and glucose-6-phosphate dehydrogenase deficiency, with particular reference to the malaria hypothesis. 529 98

40 cases of malaria seen in an 18 month period were reviewed. The clinical diagnosis was made by the general practitioner or casualty officer in 85%, and 45% of these were treated and discharged without further referral. In an area where a high awareness of malaria exists, uncomplicated Plasmodium vivax infection can be treated safely in the community. Primaquine should be given for the exo-erythrocyte stage and patients screened for glucose-6-phosphate dehydrogenase deficiency before this.
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PMID:Malaria in Brent: successful treatment in the community. 614 20

The mild course of the diseased state of haemoglobinopathies and the thalassaemias in Arabia and the interaction of the genetic abnormality and environmental factors are particularly interesting as the Peninsula exhibits a diverse climate and topography that encourages study of the interactions between various genetic and environmental factors. The present study is aimed at elucidating the incidence and frequency of these genetic abnormalities in various regions of Saudi Arabia. The relationship between haemoglobinopathies, thalassaemia and glucose-6-phosphate dehydrogenase deficiency on the one hand and malaria parasites on the other are elucidated. The results are presented in the light of the environmental factors prevailing in the area.
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PMID:Haemoglobin disorders: a pattern for thalassaemia and haemoglobinopathies in Arabia. 618 41

Glucose-6-phosphate dehydrogenase (G6PD; EC 1.1.1.49)-deficient red blood cells from male hemizygotes and female heterozygotes from the island of Sardinia were studied for their ability to support growth in vitro of the malaria-causing organism Plasmodium falciparum. Parasite growth was approximately one-third of normal in both hemi- and heterozygotes for G6PD deficiency. In Sardinians with the beta 0-thalassemia trait, parasite growth was normal except when G6PD deficiency occurred together with the thalassemia trait. The data support the hypothesis that G6PD deficiency may confer a selective advantage in a malarious area; the female heterozygote may be at a particular advantage because resistance to malaria equals that of male hemizygotes, but the risk of fatal hemolysis may be less. However, more female heterozygotes must be studied to confirm this hypothesis. No protective effect of beta 0-thalassemia trait could be demonstrated in vitro.
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PMID:Glucose-6-phosphate dehydrogenase deficiency inhibits in vitro growth of Plasmodium falciparum. 633 74

A double-blind, randomized, dose-finding, phase II mefloquine trial was carried out in 147 adult male patients suffering from acute, uncomplicated, falciparum malaria and admitted to the Hospital for Tropical Diseases, Bangkok, between January 1980 and April 1981. Mefloquine was administered as a single oral dose of 500, 750, or 1000 mg (base) in the form of the hydrochloride. The clinical and parasitological responses were satisfactory with all three dosage regimens. The cure rates for the 1000-, 750-, and 500-mg doses were 100%, 92.5%, and 95% respectively, over an observation period of 63 days.The side-effects, which were transient and generally mild, included nausea, vomiting, and diarrhoea. No significant changes were noted in haematological or biochemical parameters in any of the three groups. Sinus bradycardia, which started 4-7 days after drug administration and lasted for a few weeks, was seen in 10 patients. It was symptomless and needed no treatment.Acute brain syndrome was observed in one patient on day 21 after receiving a 1000-mg dose of mefloquine.Mefloquine was well tolerated in one case of acute renal failure, in 10 cases of moderately severe malaria with jaundice, in 13 cases with glucose-6-phosphate dehydrogenase deficiency, and in one case of thalassaemia.Mefloquine showed no effect on either gametocytes of Plasmodium falciparum or tissue forms of P. vivax.Mefloquine hydrochloride was found to be an effective drug for the treatment of falciparum malaria and tended to produce a more rapid clinical and parasitological response at the highest tested dose of 1000 mg (base).
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PMID:A phase II clinical trial of mefloquine in patients with chloroquine-resistant falciparum malaria in Thailand. 634 13

In a study in northern Liberia of the malaria and beta-thalassaemia hypothesis, the frequencies of beta-thalassaemia and HbS traits were 9.1 and 3.4% in the Mano and 9.5 and 1.7% in the Gio tribal samples. HbC and HbN were present at low frequency. G6PD deficiency was found in 16% of males. An observed increase with age of beta-thalassaemia trait frequencies was consistent with the selection hypothesis. However, we could not entirely exclude that associated iron deficiency influenced the results in the six to 11 month age group. Malaria was holoendemic; Plasmodium falciparum predominated, P. malariae and P. ovale were also identified. Plasmodium falciparum prevalence rates were similar in normal and beta-thalassaemia trait children but parasite densities were consistently lower in the latter. Using the criterion of a falciparum parasite density of 1 x 10(9) 1(-1) or greater to indicate a potentially important infection, the relative risk in beta-thalassaemia traits one to four years old from the cross-sectional study was 0.45 (upper 95% confidence interval 0.79) and 0.41 (0.61) in two to nine year trait carriers from a longitudinal study. Plasmodium falciparum gametocyte rates were lower in beta-thalassaemia trait children (P less than 0.005). The geometric mean titre of P. falciparum antibodies was lower in beta-thalassaemia trait children from the one to four year group (P less than 0.05). Otherwise immunological studies showed little difference between the different Hb types. Parasitological findings were consistent with relative resistance of HbS trait carriers towards P. falciparum infection. We found no evidence for relative resistance of beta-thalassaemia traits towards P. malariae infection nor that G6PD deficient males were more resistant to P. falciparum than those with normal activity. We conclude that the results are consistent with relative resistance of beta-thalassaemia trait carriers to P. falciparum malaria.
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PMID:Falciparum malaria and beta-thalassaemia trait in northern Liberia. 635 19

Thiol status and growth in normal and glucose-6-phosphate dehydrogenase-deficient human erythrocytes. Experimental Parasitology 57, 239-247. The relationship of the thiol status of the human erythrocyte to the in vitro growth of Plasmodium falciparum in normal and in glucose-6-phosphate dehydrogenase (G6PD)-deficient red cells was investigated. Pretreatment with the thiol-oxidizing agent diamide led to inhibition of growth of P. falciparum in G6PD-deficient cells, but did not affect parasite growth in normal cells. Diamide-treated normal erythrocytes quickly regenerated intracellular glutathione (GSH) and regained normal membrane thiol status, whereas G6PD-deficient cells did not. Parasite invasion and intracellular development were affected under conditions in which intracellular GSH was oxidized to glutathione disulfide and membrane intrachain and interchain disulfides were produced. An altered thiol status in the G6PD-deficient erythrocytes could underlie the selective advantage of G6PD deficiency in the presence of malaria.
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PMID:Plasmodium falciparum: thiol status and growth in normal and glucose-6-phosphate dehydrogenase deficient human erythrocytes. 637 52

Genetic markers have recently been found to be much more polymorphic than expected. Such extensive human polymorphisms may be partly explained by a number of genetic and environmental factors, including infectious diseases. Malaria, which was very widespread in the past and still poses a problem in many countries today, is a good candidate for research. The association between malaria and glucose-6-phosphate dehydrogenase (G6PD) deficiency is well-known, but more should be done to determine the mechanisms responsible for this positive correlation and to confirm that malaria is a strong selective factor for many other genotypes also. The present paper refers to a WHO project on genetic markers and susceptibility to infectious diseases, which is concerned mainly with G6PD deficiency and the following genetic markers: haemoglobinopathies, including the beta-thalassaemia trait and ABO, Rh, MN, Duffy, secretory types (Ss), and human leukocyte antigens (HLA). Since malaria was eradicated in Bulgaria many years ago, human populations from this country, living at different altitudes above sea-level, were used as a model for analysis of the malaria hypothesis. The data for G6PD deficiency confirm that malaria was a selective factor in lowland areas where malaria infection was more frequent in the past. It is, moreover, apparent that in addition to malaria some other factors also play a selective role.
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PMID:Frequency of glucose-6-phosphate dehydrogenase deficiency in relation to altitude: a malaria hypothesis. 696 37


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