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)

Protozoan of the phylum Apicomplexa are of high medical and veterinary importance, causing diseases such as malaria, toxoplasmosis and cryptosporidiosis. Invasive stages of apicomplexans possess organelles named micronemes, which are involved in the invasion process. We have recently characterized a protein in micronemes of Toxoplasma gondii, TgMIC3, which possess adhesive properties to host cell surface. Immunofluorescence analysis of T. gondii tachyzoite invasion showed that TgMIC3 is exocytosed and re-localised on the surface of the parasite during invasion. By being able to bind both the putative host cells and the parasites, TgMIC3 could be involved in invasion by acting as a bridge between the parasite and the host cell. Gene sequence analysis of TgMIC3 has revealed 5 partially overlapping EGF-like domains and a lectin binding-like domain, which can be involved in protein-protein or protein-carbohydrate interactions respectively. TgMIC3 is a homodimer synthetized with a N-terminal propeptide that is cleaved during trafficking to the organelle, presumably in the trans-Golgi network. The processing involves a serine protease and is required for correct binding function of TgMIC3. The exact role of this propeptide remains unexplained. It may be involved in the targetting of the protein to the micronemes by masking the region involved in interaction with membranes to avoid binding of the protein in the trafficking pathway.
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PMID:[Identification and molecular characterization of a Toxoplasma gondii microneme]. 1178 21

A laboratory trial using recombinant rK39 dipsticks for differential diagnosis of American visceral leishmaniasis (AVL) from other sympatric endemic diseases which share similar clinic features (Chagas disease, malaria, schistosomiasis and toxoplasmosis) was conducted in Venezuela. The 100% specificity of the test previously obtained in other countries was confirmed. The use of this test at the primary health care level in Venezuela for a rapid diagnosis of active AVL cases, which may avoid deaths, is recommended.
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PMID:Value of a dipstick based on recombinant RK39 antigen for differential diagnosis of American visceral leishmaniasis from other sympatric endemic diseases in Venezuela. 1180 73

The breeding system of parasitic protozoa affects the evolution of drug resistance and virulence, and is relevant to disease diagnosis and the development of chemo- and immunotherapy. A major group of protozoan parasites, the phylum Apicomplexa, that includes the aetiological agents of malaria, toxoplasmosis and coccidiosis, all have dimorphic sexual stages. The sex ratio (proportion of males produced by parasites) is predicted to depend upon the inbreeding rate, and it has been suggested that sex-ratio data offer a relatively cheap and easy method for indirectly estimating inbreeding rates. Here, we exploit a new theoretical machinery to show that there are generally valid relationships between f, Wright's coefficient of inbreeding, and sex ratio, z(*), the generality being with respect to population structure. To focus the discussion, we concentrate on malaria and show that the previously derived result, f = 1 - 2z(*), does not depend on the artificial assumptions about population structure that were previously made. Not only does this justify the use of sex ratio as an indirect measure of f, but also we argue that it may actually be preferable to measure f by measuring sex ratios, rather than by measuring departures from Hardy-Weinberg genotypic proportions both in malaria and parasites more generally.
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PMID:Inbreeding and parasite sex ratios. 1193 69

Babesiosis is considered to be an emerging tick-borne disease in humans worldwide. However, most studies on the epidemiology of human babesiosis to date have been carried out in North America, and there is little knowledge on the prevalence of infection and frequency of disease in other areas. The aim of this study was to investigate the prevalence of Babesia infections in a human population in Germany. A total of 467 sera collected between May and October 1999 from individuals living in the Rhein-Main area were tested for the presence of immunoglobulin G (IgG) and IgM antibodies to antigens of Babesia microti and Babesia divergens by indirect fluorescent-antibody (IFA) tests. These sera were derived from 84 Lyme borreliosis patients suffering from erythema migrans, 60 asymptomatic individuals with positive borreliosis serology, and 81 individuals with a history of tick bite. Cutoff values for discrimination between seronegative and seropositive results in the IFA tests were determined using sera from 120 healthy blood donors and 122 patients suffering from conditions other than tick-borne diseases (malaria, n = 40; toxoplasmosis, n = 22; syphilis, n = 20; Epstein-Barr virus infection, n = 20; and presence of antinuclear antibodies, n = 20). The overall specificities of the IFA tests for B. microti and B. divergens were estimated to be >or=97.5%. Positive IgG reactivity against B. microti antigen (titer, >or=1:64) or B. divergens antigen (titer, >or=1:128) was detected significantly more often (P < 0.05) in the group of patients exposed to ticks (26 of 225 individuals; 11.5%) than in the group of healthy blood donors (2 of 120 individuals; 1.7%). IgG antibody titers of >or=1:256 against at least one of the babesial antigens were found significantly more often (P < 0.05) in patients exposed to ticks (9 of 225) than in the control groups (1 of 242). In the human population investigated here, the overall seroprevalences for B. microti and B. divergens were 5.4% (25 of 467) and 3.6% (17 of 467), respectively. The results obtained here provide evidence for concurrent infections with Borrelia burgdorferi and Babesia species in humans exposed to ticks in midwestern Germany. They also suggest that infections with Babesia species in the German human population are more frequent than believed previously and should be considered in the differential diagnosis of febrile illness occurring after exposure to ticks or blood transfusions, in particular in immunocompromised patients.
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PMID:Seroprevalence of Babesia infections in humans exposed to ticks in midwestern Germany. 1208 58

Motion is an intrinsic property of all living organisms, and each cell displays a variety of shapes and modes of locomotion. How structural proteins support cellular movement and how cytoskeletal dynamics and motor proteins are harnessed to generate order and movement are among the fundamental and not fully resolved questions in biology today. Protozoan parasites belonging to the Apicomplexa are of enormous medical and veterinary significance, being responsible for a wide variety of diseases in human and animals, including malaria, toxoplasmosis, coccidiosis and cryptosporidiosis. These obligate intracellular parasites exhibit a unique form of actin-based gliding motility, which is essential for host cell invasion and spreading of parasites throughout the infected hosts. A motor complex composed of a small myosin of class XIV associated with a myosin light chain and a plasma membrane-docking protein is present beneath the parasite's plasma membrane. According to the capping model, this complex is connected directly or indirectly to transmembrane adhesin complexes, which are delivered to the parasite surface upon microneme secretion. Together with F-actin and as yet unknown bridging molecules and proteases, these complexes are among the structural and functional components of the 'glideosome'.
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PMID:'The glideosome': a dynamic complex powering gliding motion and host cell invasion by Toxoplasma gondii. 1213 8

Pyrimethamine is used for the treatment of toxoplasmosis and the prophylaxis of malaria. Among the well-documented side effects are megaloblastic anemia, leukopenia, thrombopenia, rash, vomiting, and diarrhea. Hyperpigmentation is a very rare side effect. In some patients, associated HIV infection makes it difficult to distinguish the reasons for the etiology. We herein describe an HIV-negative patient who developed hyperpigmentation after pyrimethamine use.
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PMID:Hyperpigmentation due to pyrimethamine use. 1218 45

In this study, the anticlastogenic effects of ascorbic acid and the protective effect of folinic acid against the formation of chromosomal aberrations in humans by pyrimethamine were investigated. Pyrimethamine is a folic acid antagonist used for the treatment of malaria and toxoplasmosis. In this study, 18 different healthy people, who do not drink alcohol and are non-smokers, were chosen as an experimental group; 0.025 mg/ml pyrimethamine was given to the lymphocyte culture, which had been prepared with the peripheral blood taken from this group. After that each of the following doses were given to the same culture: 20, 40, and 80 mM of ascorbic acid and 25, 50, and 100 mM of folinic acid. The results of the cytogenetic evaluation showed that the aberrations due to pyrimethamine in the chromosomes were reduced by ascorbic acid and folinic acid significantly, depending on the given dose.
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PMID:Inhibitory effects of ascorbic acid and folinic acid on chromosome aberrations induced by pyrimethamine in vitro. 1221 Apr 98

The increase in resistance of the malaria parasite Plasmodium falciparum to currently available drugs demands the development of new antimalarial agents. In this quest, we have found that ligands to the peripheral benzodiazepine receptor such as flurazepam, an agonist of the benzodiazepine family, and PK11195, an antagonist derived from isoquinoline, were active against Plasmodium falciparum. These two compounds effectively and rapidly inhibited parasite growth in vitro, irrespective of parasite resistance to chloroquine and mefloquine. Treatment with both drugs induced a sharp and consistent decline in parasitemia, a complete inhibition of parasite replication, and the destruction of parasites within the host red blood cells. Using electron microscopy, we showed that dramatic morphological changes, involving swollen endoplasmic reticulum and the reduction of hemozoin, were consistent with parasite death. The potent activities of flurazepam and PK11195 were also evaluated for antagonist or synergistic effects with currently used antimalarial drugs such as chloroquine and mefloquine. Moreover, flurazepam was found to be active against Toxoplasma gondii, another member of the phylum Apicomplexa. Taken together, our results indicated that benzodiazepines could be considered promising candidates in the treatment of both malaria and toxoplasmosis.
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PMID:Ligands of the peripheral benzodiazepine receptor are potent inhibitors of Plasmodium falciparum and Toxoplasma gondii in vitro. 1223 45

Humans are hosts to nearly 300 species of parasitic worms and over 70 species of protozoa, some derived from our primate ancestors and some acquired from the animals we have domesticated or come in contact with during our relatively short history on Earth. Our knowledge of parasitic infections extends into antiquity, and descriptions of parasites and parasitic infections are found in the earliest writings and have been confirmed by the finding of parasites in archaeological material. The systematic study of parasites began with the rejection of the theory of spontaneous generation and the promulgation of the germ theory. Thereafter, the history of human parasitology proceeded along two lines, the discovery of a parasite and its subsequent association with disease and the recognition of a disease and the subsequent discovery that it was caused by a parasite. This review is concerned with the major helminth and protozoan infections of humans: ascariasis, trichinosis, strongyloidiasis, dracunculiasis, lymphatic filariasis, loasis, onchocerciasis, schistosomiasis, cestodiasis, paragonimiasis, clonorchiasis, opisthorchiasis, amoebiasis, giardiasis, African trypanosomiasis, South American trypanosomiasis, leishmaniasis, malaria, toxoplasmosis, cryptosporidiosis, cyclosporiasis, and microsporidiosis.
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PMID:History of human parasitology. 1236 71

In the present study, we investigated the genotoxic effect of pyrimethamine, which is a drug used in the therapy of toxoplasmosis and malaria, in bone marrow cells of Swiss albino mice exposed to three doses (1, 4, 8 mg/kg) of this agent for eight months orally in vivo. We used a chromosome analysis and micronucleus test for evaluation of genotoxic effect. While a statistically significant change was not determined in numerical chromosome abnormalities, structural chromosome aberrations and micronuclei were increased in a dose-dependent manner by cytogenetic and statistical evaluations.
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PMID:Investigation of the genotoxic effect in bone marrow of Swiss albino mice exposed long-term to pyrimethamine. 1239 1


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