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

Red blood cell (RBC) antioxidant defense was investigated in eight individuals with hemoglobin E (Six EE and two E-B(+) thalassemia) and compared to that in six individuals with thalassemia and ten normal subjects. Individuals with hemoglobin E had increased incubated Heinz body formation (68% +/- 18%; p less than 0.001) compared to normal and thalassemic RBC (10% +/- 2% and 11% +/- 5%, respectively). Stimulated pentose phosphate shunt activity was increased in the thalassemic and decreased in the hemoglobin E RBC as compared to normal. The 2,3-diphosphoglycerate (DPG) content of the EE RBC was increased to 5.59 +/- 0.69 mumol/ml RBC as compared to normal (4.51 +/- 0.77; p less than 0.001). In the EE RBC, there was a direct correlation between Heinz body formation and DPG content (r = 0.73). Ascorbic and dehydroascorbic acid (0.1 and 1.0 mM) were able to decrease the degree of Heinz body formation in the hemoglobin E RBC. Ascorbic acid (0.1 mM) prolonged the response of the pentose shunt. Thus impaired antioxidant defense may account for the persistence of the hemoglobin E gene in areas where malaria is endemic. Oxidant medications should be used with caution in individuals of Southeast Asian origin.
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PMID:Impaired antioxidant defense in hemoglobin E-containing erythrocytes: a mechanism protective against malaria? 367 3

Mortality and fertility rates were measured from 1981 to 1983 by prospective registration of vital events as part of a community-based malaria control and health development programme in Saradidi, Kenya. There was no obvious effect of providing chloroquine phosphate for treatment of malaria in each village on mortality or fertility rates. Crude death rates were 13.1 in the year before intervention (1 May 1981 to 30 April 1982) and 12.3 after intervention (1 September 1982 to 31 August 1983). Neonatal mortality increased from 36.8 per 1000 live births pre-intervention to 49.1 during intervention. There was a slight decline in post-neonatal (one to 12 months) mortality (72.8 to 67.0) and a significant drop in early childhood mortality (25.2 to 18.2). The change in mortality rates in these two age groups were fully explained by a high rate of measles mortality in the pre-intervention period. Measles accounted for 35.7% of 284 reported deaths in infants one to 12 months of age and for 40.9% of 230 deaths in children one to four years old. There was little change in reported malaria-specific mortality rates in infants and young children most likely because of a high level of chloroquine use for treatment of presumptive illness. Perinatal mortality by area ranged between 60.4 and 81.3 pre-intervention to 79.5 to 97.2 after the control programme was instituted. Crude birth rates by area remained stable at about 40 and general fertility rates were about 200. Both pre-intervention and during intervention infants were significantly more likely to have died without medical consultation than children one to four years. However, 79.2% of 284 infants and 90.7% of 193 children died in spite of having consulted a health worker prior to death. The data suggest that a measles vaccine programme would significantly reduce mortality rates in infants and young children. The fact that the majority of infants and young children died in spite of receiving medical attention indicates both the inadequacy of curative medical services in this high mortality setting as well as the necessity for promoting preventive health measures.
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PMID:Impact on mortality and fertility of a community-based malaria control programme in Saradidi, Kenya. 368 36

The authors describe the diagnosis and the clinical course of neonatal haemolytic jaundice due to congenital deficiency of glucose 6 phosphate dehydrogenase on the basis of a series of 17 cases in children of Mediterranean or Indian ocean origin (zones previously endemic for malaria).
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PMID:[Neonatal hemolytic icterus due to congenital glucose-6-phosphate dehydrogenase deficiency. Apropos of 17 cases]. 408 97

Enzyme histochemical methods were performed on sporozoite infected liver tissue of rats in order to gain insight into the nutrition and metabolism of exoerythrocytic forms of Plasmodium berghei. The following enzymes were demonstrated in the hepatocytic stages of the parasites, obtained 41 and 48 h after inoculation of sporozoites: acid phosphatase, cytochrome oxidase, NADH-tetrazolium reductase, succinate dehydrogenase, NAD+ and NADP+ dependent isocitrate dehydrogenase, NADP+-dependent malate dehydrogenase, lactate dehydrogenases, 6-phosphogluconate dehydrogenase and glucose-6-phosphate dehydrogenases and alpha-glycerol-phosphate dehydrogenase. The results suggest that a conventional Embden-Meyerhoff pathway, pentose phosphate pathway and Krebs' citric acid cycle may in part be present in these exoerythrocytic parasites. Alkaline phosphatase, nucleoside polyphosphatase, 5' nucleotidase, glucose-6-phosphatase, alpha-glucan phosphorylase, NAD+ dependent malate dehydrogenase, amino-peptidase M and non-specific esterases were not detected by our techniques in the parasite. The enzyme distribution of this intrahepatocytic malaria parasite revealed by histochemistry is compared with the enzyme distribution in the other phases of the parasite's life cycle.
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PMID:Histochemical observations on the exoerythrocytic malaria parasite Plasmodium berghei in rat liver. 608 94

The cathepsin D of Plasmodium lophurae was purified using a combination of CM-Sephadex, pepstatin-agarose and Sephadex G-100 chromatography. The plasmodial enzyme was distinct from that of the host red cell and bovine spleen in its low isoelectric point (pI 4.3). The cathepsin D of P. lophurae, as well as plasmodial extracts demonstrating such proteinase activity, were able to digest the membrane proteins of duckling and human red cells at pH 7.4; proteolysis was not inhibited in phosphate-buffered saline by 100 microM pepstatin. Membrane proteins most susceptible to proteolysis were those of the cytoskeleton, notably bands 1 and 2 (spectrin), bands 2.1-2.6 (spectrin-binding proteins) and band 3. Membrane protein degradation by crude plasmodial extracts was partially inhibited by a combination of 10 mM FeCl3, and 10 mM phenylmethylsulfonyl fluoride in phosphate-buffered saline. The changes induced in erythrocyte membrane proteins by exposure to plasmodial cathepsin D parallel the alterations observed in red cell membranes obtained from malaria infected cells. Since the action of the plasmodial protease was confined to the inner surface of the red cell membrane, it is possible that protease-induced modifications in the red cell cytoskeleton could lead to merozoite release.
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PMID:Purification of Plasmodium lophurae cathepsin D and its effects on erythrocyte membrane proteins. 662 18

Amounts of radio-labelled substances as low as 10(-18) moles incorporated into individual cells can be measured by utilizing techniques of quantitative autoradiography. For this purpose, radioactive standard sources are processed with the labelled cells smeared to slides. Carbon-14 is a favourable isotope with regard to minimal loss of beta-disintegrations due to self-absorption, and to limited cross-fire effects complicating the attribution of silver grains to individual cells. Silver grain densities can be counted by automated microphotometry allowing on-line data processing by an interfaced computer. Rate measurements of 14C-thymidine incorporation into individual cells yield values of the DNA synthesis rate provided that the endogenous pathway of thymidine-phosphate formation has been previously blocked. From the rate values of individual cells the DNA synthesis time of a cell compartment is derived. This is an essential time parameter for the evaluation of kinetic events in proliferating cell populations. This method is applicable to human cells without radiation hazard to man, and provides an optimal source of detailed information on the kinetics of normal and diseased human haematopoiesis. Examples of application consist of thalassaemia, malaria infection, iron deficiency anaemia and acute myelogenous leukaemia.
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PMID:Quantitative carbon-14 autoradiography at the cellular level: principles and application for cell kinetic studies. 701 61

A total of 1059 persons from 14 different locations in Ibadan (the most populous city in tropical Africa) were interviewed to determine whether they had had itch reaction with each of the 12 4-aminoquinoline preparations (one amodiaquine hydrochloride, 11 chloroquine). The various trade and pharmacological names are listed in a table. Respondents were asked for what purpose the listed drugs were used: treatment of an attack of malaria fever; prevention of malaria; and other conditions or illnesses. The respondents were also asked how often each subject had an attack of malaria: monthly, every 3 months, every 6 months, once a year, once every 2-3 years, less often than this, never. Inquiry was made regarding details of the itch reaction since there was particular interest in the pruritus which, judging from previous studies, constitutes the 1 reaction most likely to make 4-aminoquinolines unpopular. Chloroquine sulphate tablets, the 8th most popular preparation, was the 6th on the list of itching incidence. There appeared to be no difference in the incidence of itching after chloroquine sulphate injection. Avloclor tablets, chloroquine phosphate injection tablets and Malarex and Aralen tablets gave a comparatively low incidence of itch reaction--3.4% and 1.4% respectively within the population studied. The incidence of itching after these 4-aminoquinoline preparations may also be estimated in the population sampled by finding the mean percentage of the subjects who itch within those who admitted taking each preparation mentioned in the questionnaire. The corrected percentage incidence gave an estimated mean of 28% compared with a mean incidence of 11% when projected to the whole population sampled. Most of the people (90%) used the 4-aminoquinoline antimalarials to treat an attack of malaria fever; 23% take them for prophylaxis and 7% in the population used the drugs for nonmalarial ailments. The misuse of the drugs for nonmalarial ailments may be related to their potency in treating malaria. In sum, the itch reaction failed to conform to a simple clinical pattern.
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PMID:Use and misuse of 4-aminoquinoline antimalarials in tropical Africa and re-examination of itch reaction to these drugs. 726 16

A paper chromatographic method for the separation and identification of complex mixtures of phosphate esters, tricarboxylic cycle acids and amino acids in biological extracts is described. The method has been applied to the investigation of carbohydrate metabolism pathways in the intraerythrocytic, simian malaria parasite Plasmodium knowlesi; on treatment of parasitized erythrocytes with [U-C14]glucose, a perchloric acid extract was prepared and separated by chromatography on Whatman 31 ET filter-paper. A simple procedure for the measurement of the specific activities of radioactive compounds without prior elution from the chromatographic support is also described.
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PMID:Paper chromatographic separation of phosphate esters, tricarboxylic cycle acids and amino acids in extracts from malaria parasites. 727 19

In the course of an investigation of hexosamine catabolism in the human malaria parasite, Plasmodium falciparum, it became apparent that a basic understanding of the relevant enzymatic reactions in the host erythrocyte is lacking. To acquire the necessary basic knowledge, we have determined the activities of several enzymes involved in hexosamine metabolism in normal human red blood cells. In the present communication we report the results of studies of glucosamine 6-phosphate deaminase (GlcN6-P) using a newly developed sensitive radiometric assay. The mean specific activity in extracts of fresh erythrocytes assayed within 4h of collection was 14.7 nmol/h/mg protein, whereas preparations from older erythrocytes that had been stored at 4 degrees C for up to 4 weeks had a mean specific activity of 6.2 nmol/h/mg. Characterization of the deaminase by chromatofocusing gave a pI of 8.55. The enzyme was optimally active at pH 9.0 and had a Km of 41 microM. The metal chelators EDTA and EGTA were non-inhibitory; however, inhibition was observed in the presence of metal ions, especially Cu2+, Ni2+ and Zn2+. In addition, the deaminase was also inhibited by several sugar phosphates including the reaction product, fructose 6-phosphate.
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PMID:Glucosamine 6-phosphate deaminase in normal human erythrocytes. 757 55

In two areas in Italy where malaria was endemic--in the Po delta and Maremma on the west coast--we have found a high prevalence of an inherited flavin-deficient red cell in the normal population, suggesting selection by malaria. This study in Sardinia enabled a direct comparison of red-cell activities of FAD-dependent glutathione reductase (EGR) and FMN-dependent pyridoxine phosphate (PNP) oxidase in an ethnically homogeneous population, between two coastal villages where malaria was endemic from 300 B.C. and two mountain villages with no history of malaria. Both enzyme activities were significantly lower on the coast, and it did not seem that this could be explained by possible small differences in dietary riboflavin. As was thought to be the case in Ferrara and Grosseto, it is probable that a genetically controlled flavin-deficient red cell was selected for by malaria. Low EGR apoenzyme activity was more common on the coast, usually explaining the accompanying low basic EGR activity, and may also have been selected for by malaria. This adds to evidence from others that the mechanism of defence of a flavin-deficient red cell against malaria may be through EGR deficiency. It could also play a part in the protection given by heterozygous beta-thalassemia. The multifactorial protection of the population against malaria is discussed.
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PMID:Deficiency of two red-cell flavin enzymes in a population in Sardinia: was glutathione reductase deficiency specifically selected for by malaria? 766 97


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