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

Gametogenesis in Plasmodium gallinaceum involves bicarbonate-dependent processes and requires a continuous supply of glucose (presumably as an energy source). Emergence and exflagellation of gametocytes, in vitro, occur independently of the CO2 tension but are rigidly correlated with the pH of the external medium. In bicarbonate-saline gametogenesis is initiated only if the pH exceeds 7.7. Our results suggest that gamete development of malaria parasites is stimulated when infected blood is exposed to air because the decrease in the CO2 tension of the blood causes its pH to rise.
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PMID:Gamete development in malaria parasites: bicarbonate-dependent stimulation by pH in vitro. 2 12

The red cells of malaria-infected mice and ducks have an increased permeability to glucose.
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PMID:Transport of carbohydrates by malarial parasites. 30 48

A report of 2 cases of acute renal insufficiency in african women, 8 months pregnant and suffering of malignant malaria. In both cases labor has been induced by artificial breaking of the membranes and use of oxytocin. One of the children was still-born and the other died 3 days later. Delivery has been followed by a resumption of the urinary flow, facilitated by high dosages of furosemide. This diuretic drug when associated with hypoprotidic diet, hypercaloric intravenous infusions of glucose hypertonic solutions supplemented with amino-acids gives a good chance of recovery without extra-renal dialysis.
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PMID:[Acute renal insufficiency caused by Plasmodium falciparum malaria in the last period of pregnancy (2 cases) (author's transl)]. 36 41

The process of mefloquine accumulation was studied in mouse erythrocytes infected with either Plasmodium berghei CS (chloroquine susceptible) or P. berghei CR (chloroquine resistant). In both cases, mefloquine was accumulated by a saturable process with an apparent dissociation constant of 2.5 x 10(-6) M and an apparent maximal capacity of 700 mumol per kg of erythrocyte pellet; uninfected mouse erythrocytes accumulated more than half as much mefloquine as infected erythrocytes. The process of accumulation was not stimulated by providing glucose as a substrate, and it was not inhibited in infected erythrocytes by azide, iodoacetate, or incubation at 2 degrees C. Although mefloquine was accumulated more effectively than chloroquine by uninfected erythrocytes and by erythrocytes infected with P. berghei CR, competition between chloroquine and mefloquine was observed, raising the possibility that the same process of accumulation serves both drugs. Chloroquine competitively inhibits mefloquine accumulation, with an apparent inhibitor constant of 1.7 x 10(-3) M, and mefloquine competitively inhibits chloroquine accumulation, with an apparent inhibitor constant of 2 x 10(-6) M. The same process of accumulation and the same group of receptors could serve both drugs if mefloquine has greater access than chloroquine to the receptors. Regardless of whether the same process serves both drugs, undiminished accumulation by erythrocytes infected with P. berghei CR provides an explanation for the superiority of mefloquine in treating chloroquine-resistant malaria.
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PMID:Chloroquine resistance in malaria: accessibility of drug receptors to mefloquine. 37 44

Determinations were made of carbohydrates in hemolymph collected from adult female mosquitoes (Anopheles stephensi). First the hemolymph was fractionated by extraction and precipitation procedures, after which qualitative and quantitative determinations of carbohydrates were made by thin layer chromatography. The most abundant sugars found in the hemolymph were glucose and trehalose, though maltose, glucuronic acid, and inositol could be found after the mosquitoes took blood meals. After the mosquitoes ingested a noninfected blood meal, their hemolymph sugar levels rose almost 4-fold. There was less of an increase following a blood meal infected with the rodent malaria parasite, Plasmodium berghei. Depletion of sugars in the hemolymph of infected mosquitoes may result from direct utilization of sugar by the malaria parasite developing within the mosquito.
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PMID:Hemolymph of Anopheles stephensi from noninfected and Plasmodium berghei-infected mosquitoes. 3. Carbohydrates. 37 18

Liposomes containing neutral glycolipids with a terminal glucose or galactose, when injected intravenously, prevented the appearance of erythrocytic forms of malaria (Plasmodium berghei) in mice previously injected with sporozoites. Inhibitory glycolipids included glucosyl, galactosyl, or lactosyl ceramide. Inhibition was not observed with liposomes containing ceramide, phosphocholine ceramide, sulfogalactosyl ceramide (sulfatide), or ganglioside GM1. Liposomes containing glycolipids did not inhibit infection transmitted by injecting blood containing erythrocytic stages of malaria. These results may have therapeutic implications in the treatment of malaria. Analysis of the mechanism of interference with the life cycle of malaria by liposomal glycolipids may yield information about the interactions of parasites with cellular membranes.
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PMID:Sporozoite-induced malaria: therapeutic effects of glycolipids in liposomes. 38 58

Comparative studies were carried out on the glucose catabolism of mouse erythrocytes infected with Plasmodium berghei, Plasmodium yoelii, Babesia rodhaini, Babesia microti and Anthemosoma garnhami, as well as on uninfected erythrocytes and reticulocytes. The results showed that there was little qualitative difference between the glucose utilization and lactate production of the parasites although quantitative differences between malaria parasites and piroplasms were observed. The rate of glucose utilization of the infected cells was at least an order of magnitude higher than the rate for uninfected erythrocytes. Reticulocytes were also shown to have higher rates of glucose utilization and lactate production than uninfected erythrocytes.
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PMID:Biochemistry of intraerythrocytic parasites. II. Comparative studies in carbohydrate metabolism. 38 68

The surface charge and lectin-binding capacity of isolated malaria parasites and host erythrocytes were analyzed and compared by chromatographic, electrophoretic, and cytochemical methods. Results indicated that at physiological pH values both freshly prepared and glutaraldehyde-fixed parasites and erythrocytes possess a net negative surface charge. Both cell types were strongly bound to cation-exchange resins and underwent cathode-directed electrophoretic migration. The isoelectric points for erythrocyte-free parasites and uninfected erythrocytes were approximately 3.0 and 4.0, respectively. The different effects of selective enzymatic digestion and solvent extraction on the electrophoretic mobilities of free parasites and erythrocytes suggested that the chemical constituents responsibile for the net negative surface charges on each type of cell are different. The surface charge of the free parasites seemed mainly to be a function of ionized phospholipids rather than of the ionogenic sialic acid moieties, which are the major contributors to the negative charge on erythrocytes. Results of lectin-binding studies indicated that specific glycosidimoieties (i.e., glucose, galactose, mannose, and n-acetyglucosamine), common to the erythrocyte surface, were either absent or in low concentration at the parasite's surface. These observations suggest that the normally intracellular malaria parasites have surface characteristics, differing from those of the host cell, characterized by a scarcity of lectin-binding receptors and sialic acid residues and by the major contribution of lipids to their surface charge.
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PMID:Surface properties of extracellular malaria parasites: electrophoretic and lectin-binding characteristics. 79 92

Rhesus monkey erythrocytes when incubated in vitro under similar conditions to those used for the cultivation of Plasmodium knowlesi-infected erythrocytes in vitro, exhibit an increase both in their osmotic fragility and in the activity of their acetylthiocholinesterase. No effect was observed on the catabolism of glucose through the glycolytic pathway or through the primary dehydrogenases of the pentose phosphate pathway. The ATP content of normal monkey erythrocytes was also unchanged during incubation in vitro. These observations indicate that incubation of erythrocytes in vitro primarily causes membrane changes. Infection of normal erythrocytes by P. knowlesi was reduced markedly by preincubation in vitro at 37 degrees C for 24 and 48 h. These results suggest that the maintenance of integrity of the surface of the erythrocyte in vitro is a necessary prerequisite for an efficient culture system for the malaria parasite.
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PMID:The effect of incubation in vitro on the susceptibility of monkey erythrocytes to invasion by Plasmodium knowlesi. 82 5

India has launched a liberalization of its economy with restructuring, privatization, and increased imports in order to achieve higher economic performance. This drive also affected the pharmaceutical industry and drug distribution, but in a negative manner. In the 1980s there were 9000 drug manufacturers that together produced up to 60,000 different preparations. In 1992, only 20,000 drugs were produced. The Voluntary Health Organization of India (VHAI) has fought for 10 years for a rational policy on medicines to halt the production of worthless or outright harmful products. For instance, anabolic steroids are sold as nutritional supplements to children, and the banned clioquinol is regularly used against diarrhea despite an international boycott. In recent years unscrupulous manufacturers have sold contaminated water as glucose for infusion bags and anti-D-immunoglobulin which was contaminated with HIV-infected blood. In northern India, a criminal organization bought up used cannulas from hospitals and repacked them for resale as new supplies. While a new medicine policy is formulated, there is a serious shortage of life-saving drugs such as insulin and rifampicin. In the last years, prices have exploded as some products have become six times more expensive. The whole national health system has undergone cost cuts to comply with an ultimatum from the World Bank and the International Monetary Fund; otherwise, sorely needed dollar loans would not be forthcoming. Funds for fighting tuberculosis and malaria have been trimmed, although AIDS and family planning budgets have been increased. One-fourth of the state health expenditures go to combat AIDS, since about 1 million people are infected with HIV. The pharmaceutical industry has also been embroiled in a patent protection wrangle with American drug exporters who claim that Retrovir or AZT (developed by Burroughs Wellcome) was pirated by the Cipla firm, whereas Cipla countered that it was ferreted out from scientific journals.
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PMID:[India: an expensive and dangerous drug]. 130 Jun 63


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