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

Parenteral quinine is the most effective treatment for severe falciparum malaria. It is not easily available in Switzerland and so dangerous delays treating patients may occur. The antiarrhythmic drug quinidine, usually stocked by hospitals, is an alternative drug for malaria treatment. We report the cases of two patients with severe malaria imported from Kenya. They were treated first with intravenous quinidine sulfate over 3 days and for another 4 days with peroral quinidine sulfate. The therapeutic response was excellent. During the 2 months posttherapeutic period no recrudescence of Plasmodium falciparum occurred. 20 mg/kg b.w./die of quinidine given intravenously seems to be an adequate dose in severe falciparum malaria.
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PMID:[The anti-arrhythmia drug quinidine as an alternative in the treatment of severe falciparum malaria]. 634 Jan 87

Serum samples from Aotus trivirgatus subsp. griseimembra monkeys obtained at different stages of a vaccination experiment were analyzed for total antibody titer to Plasmodium falciparum and were used for identifying protective antigens of the human malaria parasite. Total malarial antibody titers were higher in serum samples from protected monkeys (vaccinated with antigen in an adjuvant) than in those from unprotected monkeys (vaccinated with either antigen or adjuvant only). Parasite proteins were labeled with [3H]isoleucine, solubilized with nonionic detergent, and reacted with immune Aotus sera. Immunoprecipitates obtained were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography. Thirteen protein antigen bands in the molecular weight range 73,000 to 180,000 were resolved. Serum samples obtained from protected Aotus monkeys reacted more intensely with these proteins than samples from unprotected monkeys did. Evidence is presented that the protective antigen is not a single, normally nonimmunogenic, protein that is recognized only in protected monkeys. Rather, the present data indicate that a heightened immune response to multiple proteins correlated with in vivo protection to P. falciparum in Aotus monkeys. This finding may have a significant bearing on strategies for the development of a human P. falciparum vaccine.
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PMID:Plasmodium falciparum: protein antigens identified by analysis of serum samples from vaccinated Aotus monkeys. 636 Sep 1

The antibody response of mice to Plasmodium chabaudi adami and Plasmodium yoelii has been compared using a solid phase isotype-specific radioimmunoassay and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Serological cross-reactivity between these parasites was substantial. Studies using a radioimmunoassay detecting all classes of malaria-specific antibody demonstrated that during the early part of infection it was not possible to distinguish between homologous and heterologous reactions. Immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that 50% or more of the protein antigens detected were apparently shared by both parasites although the intensity of bands was always greater with homologous reactions. However, the distribution of isotypes in the antibody (Ab) response differed in the two infections. P. chabaudi infections were characterized by a predominant and persistent IgM response, moderate IgG2 and IgG3 and little significant IgG1 response during a primary infection. By contrast, IgM antibodies were transient in P. yoelii infection, IgG2 was the predominant isotype, and both IgG1 and IgG3 antibodies were present during a primary infection. These differences in isotypes were also detected when sera were tested on the heterologous antigen extracts suggesting that antigens shared by P. chabaudi and P. yoelii do not necessarily induce similar antibody responses in the two infections.
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PMID:Immunoglobulin isotype distribution of malaria-specific antibodies produced during infection with Plasmodium chabaudi adami and Plasmodium yoelii. 646 84

We have determined the N-terminal amino acid sequence of the first 25 amino acids of the histidine-rich protein (HisRP) isolated from granules of the avian malaria parasite Plasmodium lophurae. The protein was purified from cytoplasmic granules and shown to be 65.2 mol % histidine, close to the previously described value of 73 mol % histidine (Kilejian (1974) J. Biol. Chem. 249, 4650-4655). Ten of the first 25 residues were histidine, five of which formed the sequence His-His-His-His-His (positions 14-18). Also notable was the presence of eight acidic residues within the N-terminal 25 residues. HisRP contained no detectable carbohydrate. When the HisRP was biosynthetically labeled in cultured infected erythrocytes, incorporation of [3H]His greatly exceeded [3H]Ile. Labeled HisRP was not solubilized with 1% w/v Triton X-100 but could be solubilized with greater than or equal to 1% w/v sodium dodecyl sulfate. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis the [3H]His labeled protein migrated as a doublet (Mr 53 000 and 50 000). Only one of these bands (Mr 53 000) comigrated with the Coomassie Blue stained protein isolated by the acid-extraction procedure from purified granules. The amino acid composition of HisRP and presence of five contiguous histidine residues in the sequence studied here suggests that other sequences of several contiguous histidine residues must exist in this molecule.
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PMID:N-terminal amino acid sequence of the histidine-rich protein from Plasmodium lophurae. 648 6

Monoclonal antibodies (MAb) against gametes of the chicken malaria Plasmodium gallinaceum have been derived. All reacted with the surface of extracellular gametes of the parasite in immunofluorescent antibody reactions and all agglutinated both male and female gametes. In the absence of active complement one mu isotype MAb, la 1-D5, mediated at least 95% suppression of infectivity of the parasites to Aedes aegypti mosquitoes. Individually, MAb of the gamma 1 or gamma 2a isotypes mediated only slight suppression in the absence of active complement. Certain combinations of these MAb, however, suppressed parasite infectivity by 90 to 95%. Suppression of infectivity by the MAb was shown to be mainly due to their effects on the events leading up to or including fertilization. Certain gamma 2a isotype MAb, which otherwise mediated minimal or no suppressive effect, completely abolished infectivity of the parasites if complement was present. No target antigen could be identified by immunoprecipitation of Triton X-100 extracts of surface radioiodinated zygotes or gametes of P. gallinaceum for the mu isotype MAb. All gamma isotype MAb precipitated the same three proteins of 240,000, 56,000, and 54,000 daltons under reducing conditions on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, from extracts of radioiodinated male and female gametes. These surface proteins on gametes of both sexes of P. gallinaceum thus appear to include target antigens of anti-gamete transmission blocking immunity.
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PMID:Monoclonal antibodies against surface determinants on gametes of Plasmodium gallinaceum block transmission of malaria parasites to mosquitoes. 663 Oct 12

6 Aotus trivirgatus monkeys, which had all spontaneously recovered from an experimentally induced Plasmodium falciparum infection, were included in a clinical study concentrating on possible adverse reactions caused by a vaccine using late schizonts and merozoites as an antigen a synthetic compound, CP-20,961, as an adjuvant. Two monkeys in the study were vaccinated once, 2 twice, 1 received adjuvant alone and 1 served as a saline control. Local and general inflammatory reactions as indicated by local oedema, induration, femoral lymphadenopathy, fever and leukocytosis, were observed in all vaccinated animals and in the one monkey after the second adjuvant injection. Serum albumin and transaminase enzyme levels increased in all animals whereas plasma fibrinogen, protamine sulfate and ethanol gelation titers rose only inthe vaccinated monkeys. A transient increase of alkaline phosphatase and erythrocyte sedimentation rate was noticed in half of them. We conclude that this type of malaria vaccine causes moderate adverse reactions in Aotus but they are transitory and seem not to lead to permanent damage.
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PMID:Plasmodium falciparum merozoite vaccination in Aotus monkeys recovered spontaneously from P. falciparum infection: a clinical study. 675 60

Some strains of Plasmodium falciparum form erythrocyte rosettes that are believed to result from a lectin interaction between malaria-infected and uninfected erythrocytes. The sulfated glycoconjugate heparin and certain heparin derivatives have been observed to disrupt rosettes. To investigate this interaction further, we have studied the effects of four sulfated glycoconjugates on 15 fresh isolates of P. falciparum from Papua New Guinea. A broader range of sulfated glycoconjugates has been tested against a laboratory strain. A concentration of 1,000 micrograms/ml of dextran sulfate (molecular weight [MW] 500,000) was the most potent disrupter of rosettes. Fucoidan, heparin, and dextran sulfate (MW 5,000) were of decreasing effectiveness in 14 of 15 fresh isolates. The same relationship was true for the laboratory strain. Pentosan polysulfate and sulfatide also disrupted rosettes; chondroitin sulfates A, B, and C and keratan sulfate gave either minimal or no rosette disruption. Thus, some sulfated glycoconjugates are potent disrupters of P. falciparum erythrocyte rosettes. Sulfated glycoconjugates that are potent disrupters of P. falciparum rosettes may prove useful in identifying ligands involved in rosette formation.
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PMID:Sulfated glycoconjugates as disrupters of Plasmodium falciparum erythrocyte rosettes. 752 Nov 40

Adherence of Plasmodium falciparum-infected erythrocytes to cerebral postcapillary venular endothelium is believed to be a critical step in the development of cerebral malaria. Some of the possible receptors mediating adherence have been identified, but the process of adherence in vivo is poorly understood. We investigated the role of carbohydrate ligands in adherence, and we identified chondroitin sulfate (CS) as a specific receptor for P. falciparum-infected erythrocytes. Parasitized cells bound to Chinese hamster ovary (CHO) cells and C32 melanoma cells in a chondroitin sulfate-dependent manner, whereas glycosylation mutants lacking chondroitin sulfate A (CSA) supported little or no binding. Chondroitinase treatment of wild-type CHO cells reduced binding by up to 90%. Soluble CSA inhibited binding to CHO cells by 99.2 +/- 0.2% at 10 mg/ml and by 72.5 +/- 3.8% at 1 mg/ml, whereas a range of other glycosaminoglycans such as heparan sulfate had no effect. Parasite lines selected for increased binding to CHO cells and most patient isolates bound specifically to immobilized CSA. We conclude that P. falciparum can express or expose proteins at the surface of the infected erythrocyte that mediate specific binding to CSA. This mechanism of adherence may contribute to the pathogenesis of P. falciparum malaria, but has wider implications as an example of an infectious agent with the capacity to bind specifically to cell-associated or immobilized CS.
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PMID:Chondroitin sulfate A is a cell surface receptor for Plasmodium falciparum-infected erythrocytes. 779 Aug 15

During feeding, infected mosquitos inject malaria sporozoites into the host circulation. Within minutes, the parasites are found in the liver where they initiate the first stage of malaria infection. All species of malaria sporozoites are uniformly covered by the circumsporozoite protein (CS), which contains a conserved COOH-terminal sequence called region II-plus. We have previously shown that region II-plus is the parasite's hepatocyte-binding ligand and that this ligand binds to heparan sulfate proteoglycans (HSPGs) on the hepatocyte membrane. Using a series of substituted region II-plus peptides, we show here that the downstream basic amino acids as well as the interdispersed hydrophobic residues are required for binding of CS to hepatocyte HSPGs. We also show that this positively charged stretch of amino acids must be aggregated in order to bind to the receptor. On the basis of this information, we have synthesized a multiple antigen peptide that mimics the hepatocyte-binding ligand. This construct inhibits both CS binding to HepG2 cells in vitro as well as CS clearance in mice.
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PMID:Structural and functional properties of region II-plus of the malaria circumsporozoite protein. 800 89

Beginning in 1981, Prapokklao Regional Hospital in Chantaburi, Thailand, admitted all pregnant women with malaria to the obstetrics unit so midwives and obstetricians could learn how to better detect early signs or symptoms of malaria. Prior to 1981, they treated these women with quinine hydrochloride in a 500 ml 5% dextrose drip for 8 hours. They failed to detect hypoglycemia and pulmonary edema, however, resulting in many deaths. After 1981, they used 20 mg/kg quinine hydrochloride in a 250 ml 5% dextrose drip in 4 hours then 10 mg/kg quinine hydrochloride in a 250 ml 5% dextrose drip at the same rate at 8 hour intervals. Once the patient could take the drug orally, they administered 600 mg quinine sulfate at 8 hourly intervals for 7 days. They measured blood bilirubin levels and performed renal function tests on admission and on days 2 and 5. They monitored blood sugar levels on admission, at hourly intervals during intravenous quinine treatment, and every 4 hours during oral quinine treatment. Clinicians encouraged women who could drink to drink glucose syrup during quinine treatment. If, during treatment, a patient experienced unconsciousness or convulsions or blood sugar levels fell below 60 mg/dl, they would administer 100 ml of 50% glucose. If bilirubin levels remained high or a patient became jaundiced on day 2, clinicians monitored bilirubin on days 3 and 4. If levels increased, they reduced the dose 33% until the situation improved. They recorded urinary output hourly and measured central venous pressure. If the patient had normal pressure, but urinary output was less than 30 ml/hour, clinicians prescribed a diuretic. They kept patients in a propped-up position to reduced the likelihood of pulmonary edema. They monitored fluid intake and output and, in severe cases, central venous pressure. They allowed just enough fluid intake to maintain the pressure at 10-12 mm H20 and urine output at no less than 30 ml/hour. These efforts reduced maternal deaths in the unit from 341 to 54/100,000 live births (1981 - 8 deaths; 1986 - no deaths).
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PMID:Malaria in pregnant women: action for survival. 818 99


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