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

Anopheles darlingi fed on eight falciparum malaria patients with gametocytes before and after treatment with quinine sulfate or quinine sulfate plus tetracycline became infected. Quinine and quinine plus tetracycline had no apparent sporontocidal or gametocytocidal effect on late stage immature and mature gametocytes. Plasmodium falciparum gametocytes are persistent and infected mosquitoes for up to 21 days after patients were treated with quinine plus tetracycline. Sporogonic development was similar for groups of mosquitoes fed before and after patients were treated with these schizontocides. The percentages of infected mosquitoes that developed salivary gland infections were also similar for groups of mosquitoes fed before and after treatment. Twenty-four hours after treatment with 45 mg of primaquine phosphate, falciparum malaria patients were not infective to An. darlingi.
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PMID:Infection of Anopheles darlingi fed on patients with Plasmodium falciparum before and after treatment with quinine or quinine plus tetracycline. 185 64

Humans infected with Plasmodium falciparum frequently have elevated levels of proteins in their urine, but it is unclear if any of these proteins are parasite antigens or antimalarial antibodies. To resolve this question, urine samples from malaria patients and controls living in Thailand and Ghana were evaluated. Urine samples from 85% of the patients had elevated protein levels and contained proteins with Mrs ranging from less than 29,000 to greater than 224,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Antisera were produced against urine from infected and control subjects. Antisera raised against infected, but not control, urine were positive by indirect immunofluorescence on P. falciparum parasites and immunoprecipitated approximately 12 unique bands from extracts of parasites metabolically labeled with 35S-methionine. These data suggest that a variety of P. falciparum antigens are released into urine during acute infection. It is also likely that anti-P. falciparum antibodies are present in the urine of malaria patients because samples from these patients, but not controls, were positive in indirect immunofluorescence assays and immunoprecipitated at least 19 P. falciparum antigens from extracts of metabolically labeled parasites. The detection of malarial antigens and antibodies in urine may lead to a new approach for the diagnosis of malaria.
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PMID:Detection of antigens and antibodies in the urine of humans with Plasmodium falciparum malaria. 186 42

Inbred BALB/c mice were either immunized with Triton X-100-extracted antigens of blood-stage Plasmodium yoelii or infected with P. yoelii and cured in three successive schedules. Whereas the immunized BALB/c became only partially protected from subsequent challenge infection with blood-stage P. yoelii, the convalescent mice acquired total immunity. When total P. yoelii antigen extract was resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred to nitrocellulose, and immunoblotted with anti-P. yoelii serum, five major protein bands of 150, 84, 40, 19, and 16 kDa were recognized by the sera of fully protected convalescent mice but not by the sera of partially protected mice. The utility of comparing reactivities of sera from fully protected and partially protected malaria hosts and the possibility that antigens uniquely recognized by the convalescent mouse sera may contribute to immunity against P. yoelii infection are discussed. Although previously reported to be an effective adjuvant for immunization against P. yoelii infection in (BALB/c x C57BL)F1 hybrid mice, saponin did not promote protection any better than did Freund adjuvant in BALB/c mice immunized with detergent-extracted P. yoelii antigen. Most of the P. yoelii proteins (14 to 250 kDa) found in Triton X-100 extracts of P. yoelii-parasitized erythrocytes isoelectrofocused as a single peak in the pH region 4.4 to 4.6, suggesting a rationale for previous findings that the most anti-P. yoelii protective and T-helper activities are induced by antigens isoelectrically focused in a fraction of similar pH.
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PMID:Antibody recognition and isoelectrofocusing of antigens of the malaria parasite Plasmodium yoelii. 193 50

Methods were developed for the production of clinical grade malaria vaccine candidates expressed in E. coli by recombinant DNA technologies. The essential features of the purification protocol consist of (1) mechanical breakage of host cells and solubilization of the recombinant proteins in 6 M guanidine hydrochloride; (2) ammonium sulfate fractionation; (3) affinity chromatography on a Ni(2+)-chelate gel in the presence of 6 M guanidine hydrochloride; and (4) ion exchange chromatograph on a Phospho Ultrogel column in the presence of 6 M urea. The use of undesirable chemicals (PMSF, DFP, TFA, acetonitrile, etc.) was avoided rather than demonstrating their complete removal after the purification steps. Testing of chromatographic fractions for host-cell proteins and the elimination of fractions with E. coli protein content was found necessary to obtain a final product that contained less than 0.01% of host derived proteins. The recombinant proteins were renatured either from 8 M urea or from 6 M guanidine hydrochloride by increasing the pH to 10.5 in the presence of glycine and EDTA, reduction with DTT, dilution to a protein concentration below 1 mg.ml-1, and dialysis against 0.9% NaCl. The method presented here can be tailor-fit, with minor modification, for the purification of almost any recombinant protein and the final product satisfies current regulations concerning the production of clinically acceptable therapeutic products.
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PMID:Preparation of clinical grade proteins produced by recombinant DNA technologies. 194 Mar 92

The malaria-induced surface antigens on Plasmodium falciparum-infected erythrocytes from West African patients were characterized by agglutination of infected cells by human sera, surface immunofluorescence of live infected cells, inhibition of cytoadherence to C32 melanoma cells by human sera, immunoelectron microscopy (immunoEM), and immunoprecipitation. In a nonimmune individual, serum antibody reactivity to surface antigens of infected cells was acquired during convalescence, as tested by all five methods, and was generally parasite isolate-specific. By contrast, adult hyperimmune West African sera reacted with many isolates, including isolates from geographically distinct regions. A quantitative correlation was established between agglutination and surface immunofluorescence assay titers, and between surface immunofluorescence assay and immunoEM reactivity, suggesting that a single antigen or a set of coexpressed antigens is being detected. Surface iodination of infected cells identified trypsin-sensitive high M, antigens in the sodium dodecyl sulfate extract. All sera tested that agglutinated infected cells also immunoprecipitated these antigens. The same surface antigens were immunoprecipitated by the homologous convalescent serum as by adult sera. By immunoEM these antigens were localized exclusively at the knob-like protrusions of infected cells, where they may participate in adherence to vascular endothelium.
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PMID:Characterization and localization of Plasmodium falciparum surface antigens on infected erythrocytes from west African patients. 207 55

Twenty eight adult male patients with acute uncomplicated falciparum malaria which showed RI or RII responses to quinine sulfate at the dosage of 600 mg 8 hourly for 7, 10 or 14 days were treated with a single dose of mefloquine (Lariam); 25 patients received 1000 mg, 2 received 750 mg and 1 received 500 mg. The initial response was good; there was no RII or RIII response. Three patients were lost to followup. Of 25 patients who stayed in the Bangkok Hospital for Tropical Diseases where there was no malaria transmission for 28-65 days, only one patient in the 1000 mg group had recrudescence on day 21. The cure rate was 96%. Our prospective study suggests that mefloquine was effective in the treatment of quinine resistant falciparum malaria and the risk of cross-resistance between quinine and mefloquine in P. falciparum in vivo is very low.
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PMID:Quinine resistant falciparum malaria treated with mefloquine. 209 15

Data on a technique for the detection of antigen from arthropod vectors in a dot immunobinding assay are presented. In this system, antigen present in the vector was first solubilized in sodium dodecyl sulfate. The homogenate from this process was microfiltered through a two-membrane sandwich; target antigen molecules passed through the first membrane and were immobilized on the second one. The first membrane was nonbinding and served to impinge debris. The second membrane was a high-protein-binding-capacity hydrophobic polyvinylidene difluoride membrane. High signal-to-noise ratios were produced by this method, which is readily adaptable for field use. This assay was used for malaria sporozoites, but it can serve as a general technique that is applicable to other arthropod vectors and etiologic agents.
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PMID:Processing and microfiltration of mosquitoes for malaria antigen detection in a rapid dot immunobinding assay. 220 8

N,N'-Bis(benzyl)polyamine analogs were found to be substrates for highly purified polyamine oxidase. Metabolism of these analogs was apparently dependent on molecular O2 and resulted in the formation of benzaldehyde, H2O2, and a polyamine analog with free terminal amines. The debenzylation reaction was optimal between pH 9 and 10, identical to the pH optimum for polyamine oxidase activity when N1-acetylspermine was used as the substrate. On a molecular sieve column the debenzylating activity co-eluted with N1-acetylspermine oxidizing activity, at an apparent molecular mass of approximately 65 kDa. The purified enzyme also appeared to have a molecular mass of approximately 65 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Debenzylation of the bis(benzyl)polyamines was competitively inhibited by N1-acetylspermine and N1-acetylspermidine. The specific irreversible inhibitor of polyamine oxidase, N1,N4-bis(buta-2,3-dienyl)butanediamine also inhibited the debenzylation, whereas inhibitors of diamine and monoamine oxidases did not. The evolution of benzaldehyde from bis(benzyl)polyamine analogs by polyamine oxidase allowed the development of a simple rapid spectrophotometric assay for use in the measurement of polyamine oxidase activity in partially purified tissue or cell extracts. Further, metabolism of a bis(benzyl)polyamine analog by polyamine oxidase was found to be an important element in the growth inhibitory properties of the compound in a mouse model of malaria.
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PMID:Bis(benzyl)polyamine analogs as novel substrates for polyamine oxidase. 229 9

Two new methods for the simultaneous determination of chloroquine and its two main metabolites (monodesethylchloroquine and bisdesethylchloroquine) in biological samples, radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA), are described. Antiserum is produced in rabbits immunized with N-(2-carboxyethyl)desethylchloroquine:protein conjugate. Besides chloroquine, this antiserum recognizes with good affinity the two main metabolites, monodesethylchloroquine and bisdesethylchloroquine (70 and 40% of crossreaction, respectively). Amodiaquine cross reacts by 4.5%; cross reactions with monodesethylamodiaquine, bisdesethylamodiaquine, and other antimalarial drugs are less than 1%. No extraction step or sample preparation is required for either system. Sensitivity limits are, respectively, 0.70 nM (3 pg of chloroquine sulfate measured in 10 microL of plasma sample) for RIA, and 10 nM (22 pg of chloroquine sulfate measured in 5 microL of plasma sample) for ELISA. The interassay coefficients of variation are, respectively, less than 10 and less than 16% for RIA and ELISA in the range 14-410 nM (6-180 ng/mL). The results of both methods are well correlated (r = 0.97) and correlate with spectrophotometry (r = 0.98) and HPLC results (r = 0.93). Because of their high sensitivity, both methods can be used in the case of chloroquine poisoning and in the control of malaria prophylaxis and treatment.
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PMID:Sensitive radioimmunoassay and enzyme-linked immunosorbent assay for the simultaneous determination of chloroquine and its metabolites in biological fluids. 231 70

The effect of iron therapy on malarial infection was investigated in Papua New Guinea, where malaria is endemic. Prepubescent schoolchildren with hemoglobin levels of 8-12 g/dl were randomly assigned to receive either 200 mg ferrous sulfate or a placebo twice daily for 16 weeks. Iron status and malarial infection were assessed at baseline, after 6 and 16 weeks of therapy, and 8 weeks after therapy was discontinued. Iron status was significantly improved by the treatment. The treatment did not significantly affect parasite rate, parasite density, or levels of anti-malarial IgG. No changes in spleen size were observed in either group. Furthermore, there was no significant difference between the groups in reported episodes of suspected malaria during the therapy. These results suggest that, in malaria endemic areas, oral treatment for iron deficiency can be carried out in semi-immune or immune schoolchildren without adverse consequences.
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PMID:The effect of iron therapy on malarial infection in Papua New Guinean schoolchildren. 264 55


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