| accumulation of chloroquine by membrane preparations from plasmodium falciparum. | chloroquine susceptibility and resistance have been associated respectively with the uptake and efflux of chloroquine by plasmodium falciparum. we made membrane preparations from parasitized and unparasitized red cells in order to study chloroquine accumulation in a cell-free system. the accumulation of [3h]chloroquine by these preparations is inhibited by unlabeled chloroquine and thus is specific. only membranes from parasitized red cells demonstrate time-dependent chloroquine accumulation; me ... | 1990 | 2148609 |
| [resolutive and recurrent oligohydramnios caused by plasmodium falciparum malaria]. | | 1990 | 2148621 |
| cytokine production in lethal and non-lethal murine malaria. | levels of ifn-gamma, il-2 and il-4 were measured in vitro during the course of non-lethal plasmodium chabaudi adami and lethal p. chabaudi strain 1309 infections in balb/cbyj mice. spleen cells from mice infected with the non-lethal plasmodium had a higher initial response to p. chabaudi antigens than mice infected with p. chabaudi strain 1309, as determined by measuring all three lymphokines. we conclude that both th1 and th2 subsets of t helper lymphocytes are activated during p. chabaudi adam ... | 1990 | 2149359 |
| increased gamma delta t cells in acute plasmodium falciparum malaria. | the t cell receptor of gamma delta is normally expressed on a small percentage of peripheral lymphocytes. although the role of gamma delta t cells in the physiologic immune response is still unknown, there is accumulating evidence that gamma delta t cells may participate in the immune response to mycobacterial and other infectious organisms. in this study, we have quantitated the number of circulating gamma delta t cells during acute plasmodium falciparum malaria. the results indicate that gamma ... | 1990 | 2149360 |
| structure of a plasmodium yoelii gene-encoded protein homologous to the ca(2+)-atpase of rabbit skeletal muscle sarcoplasmic reticulum. | a cation-transporting atpase gene of plasmodium yoelii was cloned from the parasite genomic library using an oligonucleotide probe derived from a conserved amino acid sequence of the phosphorylation domain of the aspartyl phosphate family of atpases. the complete nucleotide sequence was determined and it predicts a 126,717 mr encoded protein composed of 1115 amino acids. northern blot analysis revealed that the gene is transcribed during the asexual stages of parasite development. the p. yoelii ... | 1990 | 2150071 |
| in vitro cell-mediated immune responses to plasmodium falciparum schizont antigens in adults from a malaria endemic area: cd8+ t lymphocytes inhibit the response of low responder individuals. | plasmodium falciparum schizont extract and purified protein derivative were used to stimulate peripheral blood mononuclear cells obtained from healthy aparasitemic gabonese individuals with lifelong exposure to malaria infection and non-gabonese control subjects who have had had no clinical malaria. in vitro lymphoproliferation was measured by uptake of tritiated thymidine, while production of interleukin-2, interferon-gamma, and soluble cd8+ were measured by immunoenzymatic assays. enumeration ... | 1990 | 2151024 |
| hepatic phase of malaria: a crucial role as "go-between" with other stages. | besides potential interest in itself, the hepatic stage of malaria might play a crucial role as "go-between" with other stages. when present in the parasitophorous vacuole, antibodies induced by both sporozoite and erythrocytic stages efficiently disturb hepatic development of the parasite. likewise previous and ensuing erythrocytic stages can modulate the "shielded" phase by cytokines, directly or as a result of a cascade of events, and by mhc-restricted or antibody-dependent cytotoxic mechanis ... | 1990 | 2151269 |
| t lymphocytes from mice immunized with irradiated sporozoites eliminate malaria from hepatocytes. | when mice are immunized with radiation-attenuated sporozoites they are solidly protected against sporozoite challenge by an immune response that has been shown to require cd8+ lymphocytes in several strains of mice. the target of this cd8+ t-cell-dependent immunity has not been established. immune balb/c mice were shown to develop malaria-specific, cd8+ t-cell-dependent inflammatory infiltrates in their livers after challenge with plasmodium berghei sporozoites. spleen cells from immune balb/c a ... | 1990 | 2151270 |
| plasmodium ovale in indonesia. | we report 34 infections by plasmodium ovale found among 15,806 blood film examinations taken between 1973 and 1989 from several sites in indonesia. twenty five of the p. ovale infections occurred in a single sample of 514 people living in owi, irian jaya. we detected five additional infections at 3 other sites in irian jaya. other infections by p. ovale occurred at two sites in west flores. another infection has already been reported from east timor. despite relatively frequent sampling of popul ... | 1990 | 2151542 |
| from the centers for disease control. transmission of plasmodium vivax malaria--san diego county, california, 1988 and 1989. | | 1990 | 2155329 |
| recommendations for the prevention of malaria among travelers. | recommendations for the prevention of malaria among travelers have been developed by cdc in consultation with representatives from the offices of medical services of the department of state and the peace corps; the division of experimental therapeutics of the walter reed army institute of research; the office of the surgeon general, u.s. army; the office of the surgeon general, u.s. air force; and the bureau of medicine and surgery, u.s. navy. resistance of plasmodium falciparum to chloroquine h ... | 1990 | 2156146 |
| recrudescence of entopolypoides macaci mayer, 1933 (babesiidae) infection secondary to stress in long-tailed macaques (macaca fascicularis). | parasites were found in red blood cells of two long-tailed macaques (macaca fascicularis) imported from indonesia and housed in the washington regional primate research center breeding colony for 7 years or longer. both macaques developed parasitemias secondary to stress (type d retrovirus in one case and severe trauma in the other). entopolypoides macaci (babesiidae) was diagnosed on the basis of morphology from peripheral blood smears stained with wright's stain. antibodies against babesia sp. ... | 1990 | 2157097 |
| phospholipid composition, cholesterol content and cholesterol exchange in plasmodium falciparum-infected red cells. | the membrane lipid composition and [3h]cholesterol exchange rate were studied in both normal human erythrocytes and those infected with the human malaria plasmodium falciparum. the host cell membrane was separated from parasite membranes using the affigel (731) bead method. the purity of the membrane preparation was very high, as judged by sds-page, and in several instances was estimated to be greater than 98% as determined by the activity of the parasite membrane-specific enzyme, choline phosph ... | 1990 | 2157152 |
| [malaria tropica with activation of blood coagulation and detection of tumor necrosis factor (nf-alpha) in serum]. | a 38-year-old patient with cerebral p. falciparum malaria was admitted 12 days after a short trip to kenya. the serum level of tumor necrosis factor (tnf-alpha) was elevated (251 pg/ml). in contrast, protein c (plasma activity 36.1%; antigen concentration 31.7%) and protein c inhibitor 1 (activity 0.55 u/ml) levels were decreased. this suggested a state of functional activation of the clotting system which was confirmed by elevated levels (4.8 ng/ml) of circulating thrombin-antithrombin-iii-comp ... | 1990 | 2157919 |
| from the centers for disease control. recommendations for the prevention of malaria among travelers. | recommendations for the prevention of malaria among travelers have been developed by cdc in consultation with representatives from the offices of medical services of the department of state and the peace corps; the division of experimental therapeutics of the walter reed army institute of research; the office of the surgeon general, u.s. army; the office of the surgeon general, u.s. air force; and the bureau of medicine and surgery, u.s. navy. resistance of plasmodium falciparum to chloroquine h ... | 1990 | 2159078 |
| in vitro effects of primaquine and primaquine metabolites on exoerythrocytic stages of plasmodium berghei. | the antimalarial activities of primaquine and its metabolites against exoerythrocytic (ee) stages of plasmodium berghei in vitro were compared with their abilities to spontaneously generate activated oxygen. a quantitative relationship between the number of sporozoites and the number of ee merozoites produced was established. the reduction in the number of merozoites was used as an assay of drug activity. the ed50 of primaquine, 3.7-3.9 x 10(-6) m, was the concentration of drug that reduced the ... | 1990 | 2164790 |
| [uncommon clinical aspects of plasmodium falciparum malaria]. | an attack of malaria can be lethal; however, besides this classic form, clinical cases are less brutal, often with blood disorders, related to plasmodium falciparum infection resistant to chloroquine. because of the importance of chloroquinoresistance through the world, chemoprophylaxis is very difficult, and the fight against mosquitoes' bites is once again very important. | 1990 | 2165242 |
| antimalarial activity of diethyldithiocarbamate. potentiation by copper. | the antimalarial activity of diethyldithiocarbamate (ddc) in vitro was potentiated by subtoxic concentrations of copper. ddc was also more potent in the presence of an intracellular source of copper, such as when parasites were grown in superoxide dismutase (sod)-loaded erythrocytes. these data suggest that ddc forms a complex with copper, either intracellularly or extracellularly, which is toxic to malarial parasites. the exact cause of this toxicity is not known, but may be due to a membrane e ... | 1990 | 2165401 |
| endopeptidase activities of streptococcus cremoris. | | 1990 | 2165941 |
| in vitro analysis of epstein-barr virus: host balance in patients with acute plasmodium falciparum malaria. i. defective t-cell control. | peripheral blood lymphocytes from healthy, epstein-barr virus (eb-virus)-seropositive donors and from patients with acute plasmodium falciparum malaria were tested for their cytotoxicity towards autologous eb-virus-infected b-cells using an in vitro regression assay. of the 18 cultures from control donors, 88.8% showed the normal pattern of regression. of the 20 malaria patients in the study, 40% failed to exhibit the normal pattern observed in the control group. analysis of the lymphocyte subse ... | 1990 | 2166284 |
| the duffy receptor family of plasmodium knowlesi is located within the micronemes of invasive malaria merozoites. | plasmodium vivax and plasmodium knowlesi merozoites invade human erythrocytes that express duffy blood group surface determinants. a soluble parasite protein of 135 kd binds specifically to a human duffy antigen. using antisera affinity purified on the 135 kd protein, we cloned a gene that encodes a member of a p. knowlesi family of erythrocyte binding proteins. the gene is a member of a family that includes three homologous genes located on separate chromosomes. two genes are expressed as major ... | 1990 | 2170017 |
| [in-vivo evaluation of plasmodium falciparum sensitivity to chloroquine in abidjan]. | in vivo tests of plasmodium falciparum chloroquine sensitivity were conducted in october and november, 1988 with 81 children aged 5 to 9 in several districts of abidjan, ivory coast. the who standard scheme covering 7 days on basis of 25 mg per kilo spread over 3 days resulted in a therapeutic failure in 29.6 per cent cases. nevertheless, a drop in overall parasitemia by over 80 per cent was noted from day-0 to day-2 in 70 per cent of visible resistance. only in vivo tests conducted at a later s ... | 1990 | 2170042 |
| [prophylaxis of malaria. current need for awareness of risk]. | | 1990 | 2170904 |
| effect of mitochondrial inhibitors on adenosinetriphosphate levels in plasmodium falciparum. | 1. the effects of mitochondrial inhibitors on the atp levels of intraerythrocytic plasmodium falciparum have been studied. 2. changes in parasite atp or adp levels with time in response to various mitochondrial inhibitors appear quite complex; atp levels may be initially depressed and then elevated above normal, but the nature of the response depends upon the stage in the intraerythrocytic cycle and in some cases upon the concentration of the inhibitor used. 3. after ca 2 hr incubation of cultur ... | 1990 | 2171868 |
| possible roles of ca2+ and cgmp as mediators of the exflagellation of plasmodium berghei and plasmodium falciparum. | the roles of ca2+ and cyclic nucleotides as secondary, intracellular messengers for exflagellation of plasmodium berghei and plasmodium falciparum were investigated. treatment with ca2+ antagonists such as tmb-8 (an inhibitor of intracellular ca2+ release) or w-7 (a calmodulin inhibitor) strongly inhibited exflagellation induced by alkaline medium at ph 8.0 whereas egta (a ca2+ chelator) or nicardipine and nifedipine (ca2+ channel inhibitors) had no effect. these results may indicate that mobili ... | 1990 | 2172816 |
| long insertions within telomeres contribute to chromosome size polymorphism in plasmodium berghei. | during prolonged in vivo mitotic multiplication of a plasmodium berghei anka clone (8417hp), parasites that contained an enlarged version of chromosome 4 were observed. restriction mapping and hybridization results demonstrated that the extra dna present in the enlarged chromosome consists of 2.3-kb tandem repeats, known to be normally located in subtelomeric position at several chromosomal ends but absent in the original chromosome. the inserted 2.3-kb units appeared to interrupt one of the ori ... | 1990 | 2174115 |
| ion metabolism in malaria-infected erythrocytes. | malaria parasites of the genus plasmodium spend much of their asexual life cycle inside the erythrocytes of their vertebrate hosts. parasites presumably have to exploit metabolic and transport mechanisms to adapt themselves to the host erythrocyte's physicochemical environment. this review surveys the metabolism and transport of ca2+, alkali cations, and h+ in malaria-infected erythrocytes. the ca2+ content of plasmodium-infected erythrocytes increases as the parasite matures. an increase in the ... | 1990 | 2175223 |
| activity of human volunteer sera to candidate plasmodium falciparum circumsporozoite protein vaccines in the inhibition of sporozoite invasion assay of human hepatoma cells and hepatocytes. | sera from human volunteers immunized with either synthetic peptide (nanp)3-tt or recombinant protein r32tet32 plasmodium falciparum cs vaccines were tested in the inhibition of sporozoite invasion (isi) assays using human hepatoma (hepg2-a16) cells or primary human hepatocytes. sera or purified immunoglobulin (ig) from volunteers who were completely protected against p. falciparum sporozoite challenge had higher isi activity than sera from non-protected volunteers, or the highest titre endemic s ... | 1990 | 2175464 |
| heterologous expression of active thymidylate synthase-dihydrofolate reductase from plasmodium falciparum. | the coding sequence of the bifunctional thymidylate synthase-dihydrofolate reductase (ts-dhfr) from a moderately pyrimethamine-resistant strain (hb3) of plasmodium falciparum was assembled in a puc expression vector. the coding sequence possesses unique nco1 and xba1 sites which flank 243 bp of the dhfr gene that include all point mutations thus far linked to pyrimethamine resistance. wild-type (3d7) and highly pyrimethamine-resistant (7g8) ts-dhfrs were made from this vector by cassette mutagen ... | 1990 | 2176883 |
| the circulating platelet in acute malaria infection. | | 1990 | 2178670 |
| glucose-6-phosphate dehydrogenase from plasmodium berghei: kinetic and electrophoretic characterization. | evidence is given for the existence of a parasite-specific glucose-6-phosphate dehydrogenase (g6pd) in plasmodium berghei by characterization of its kinetic and electrophoretic properties. from infected rat erythrocytes the parasites were isolated, washed, and lysed. g6pd was purified by affinity chromatography with 2'5'-adp-sepharose 4b, although the separation of the malaria-specific enzyme from that of the host cell was not complete. malarial g6pd significantly differed from the red cell enzy ... | 1990 | 2178950 |
| thymidylate synthase-dihydrofolate reductase in protozoa. | in protozoa, thymidylate synthase (ts) and dihydrofolate reductase (dhfr) exist on the same polypeptide. the dhfr domain is on the amino terminus, ts is on the carboxy terminus, and the domains are separated by a junction peptide of varying size depending on the source. the native protein is a dimer of two such subunits and is 110-140 kda. most studies of bifunctional ts-dhfr have been performed with the protein from anti-folate resistant strains of leishmania major, which show amplification of ... | 1990 | 2178951 |
| malaria and glucose 6-phosphate dehydrogenase deficiency in populations with high and low spleen rates in madang, papua new guinea. | previous studies in madang have demarcated 2 groups of women, one with high spleen rates (hs group) and the other with low spleen rates (ls group). an association between glucose 6-phosphate dehydrogenase (g6pd) deficiency and low spleen rates was investigated in 196 hs and 106 ls group men. prevalence was 12.2 and 9.4%, respectively. parasite and spleen rates were lower in deficients in the hs group. differences in prevalence between hs group villages were observed which may be related to the i ... | 1990 | 2179119 |
| impairment of plasmodium falciparum-specific antibody response in severe malaria. | serum antibody response to plasmodial antigens was investigated in 97 thai patients with plasmodium falciparum malaria. no difference in immunoglobulin g (igg) antibody levels was detected between groups without or with cerebral manifestations of malaria (n = 40). in patients with the most severe form of the disease, i.e., those who died despite adequate therapy (n = 12), antibody detected in the immunofluorescent-antibody test was found at lower levels than in those who recovered (geometric mea ... | 1990 | 2179259 |
| splenic fc receptor function in host defense and anemia in acute plasmodium falciparum malaria. | to determine splenic fc receptor function in patients with acute plasmodium falciparum malaria, the clearance of igg-coated autologous 51cr-labeled erythrocytes in 20 patients and 10 normal controls was studied. clearance half-times were directly correlated with both the absolute parasite count (r = .635, p less than .005) and hematocrit (r = .791, p less than .001). clearance half-times in patients varied from 1.0 to 96.3 h (median, 14.8 h) while those of controls ranged from 8.0 to 80.3 h (med ... | 1990 | 2179426 |
| fatal plasmodium falciparum malaria after an inadequate response to quinine treatment. | a 24-year-old man with severe plasmodium falciparum malaria died after 77 h of treatment with full parenteral doses of quinine. his peripheral parasitemia at death exceeded the level on admission. plasma concentrations of quinine were abnormally low throughout. this case emphasizes the importance of pharmacokinetic factors in determining the therapeutic response in severe p. falciparum malaria. | 1990 | 2179427 |
| changes in plasma lipoproteins in acute malaria. | plasma lipid and lipoprotein concentrations were monitored in 16 patients with acute malaria. plasma high density lipoprotein (hdl) levels decreased dramatically during the first 3 d after diagnosis to around 0.2 mmol l-1 (reference range 0.8-1.6 mmol l-1). the low hdl levels were related to parasitaemia, and rapidly recovered after successful therapy. plasma triglyceride concentrations were moderately increased and plasma low density lipoprotein (ldl) cholesterol concentrations decreased during ... | 1990 | 2179459 |
| human and murine macrophages produce tnf in response to soluble antigens of plasmodium falciparum. | heat-stable antigens of rodent malarial parasites induce the release of tumour necrosis factor (tnf) from mouse macrophages, in vitro and in vivo. we report here that analogous antigens of plasmodium falciparum trigger the release of tnf from human monocytes in vitro, in conditions that exclude the effects of any contaminating endotoxin. these antigens also induced tnf release from a murine monocytic cell line and from the peritoneal macrophages of several strains of mice, including the lps-hypo ... | 1990 | 2179828 |
| stage-specific gametocytocidal effect in vitro of the antimalaria drug qinghaosu on plasmodium falciparum. | qinghaosu, an anti-malaria drug, has been found to kill not only asexual blood stages but also the early stages of gametocytes of plasmodium falciparum. the effect of qinghaosu in vitro depends on the concentration of the drug as well as on the initial parasitemia level (ic50 = 10-20 nm with 1% initial parasitemia). resistance of p. falciparum to other anti-malaria drugs, e.g., chloroquine and pyrimethamine, did not affect susceptibility of its asexual and sexual stages to qinghaosu. gametocytoc ... | 1990 | 2179946 |
| chemotherapy: principles in practice--a case study of the philippines. | this paper reports on the principles that form the basis of chemotherapy and examines the operational considerations that affect their practice in a developing country like the philippines, where malaria endemicity is synonymous with difficult topography, poor public health infrastructure, and alternative means of obtaining medication. the practice of using microscopic diagnosis for radical treatment is followed routinely and uniformly. where policy dictates that all fever cases be screened, the ... | 1990 | 2180084 |
| comparison of experimental infectivity and development of plasmodium vivax in anopheles sacharovi and an. superpictus in turkey. | a study has been made of the infectivity and the sporogenic development of plasmodium vivax in anopheles sacharovi and an. superpictus under experimental conditions. an. superpictus showed a slightly lower rate of feeding on human bait, oocyst development, and sporozoite infection of the salivary glands, with ratios of 89.3:100, 89:100, and 98:100, respectively. an. superpictus completed sporogony in 10-14 days with an average of 11.7 days, and an. sacharovi within 8-12 days with an average of 9 ... | 1990 | 2180330 |
| infection of chimpanzees with the uganda i/cdc strain of plasmodium malariae. | nine splenectomized chimpanzees were infected with the uganda i/cdc strain of plasmodium malariae. two had no history of previous malarial infection, whereas 6 had been infected with p. vivax and 1 with p. vivax and p. ovale. the animals with no previous infection had maximum parasitemias of 8,740 and 10,800/mm3. the other animals had maximum parasite counts of 930-75,700/mm3. anopheles freeborni, an. stephensi, an. dirus, an. maculatus, an. quadrimaculatus, an. culicifacies, an. arabiensis, and ... | 1990 | 2180332 |
| discovery and disease control. | | 1990 | 2180333 |
| sporontocidal activity of the antimalarial wr-238605 against plasmodium berghei anka in anopheles stephensi. | the influence of wr-238605 (8-[(4-amino-1-methyl-butyl) amino]-2,6-dimethoxy-4-methyl-5-[3-tri-fluoromethylphenoxyl] quinoline succinate) on the sporogonic development of a plasmodium berghei anka clone was determined. anopheles stephensi were fed on p. berghei infected mice treated 90 min earlier with 25 or 50 mg wr-238605/kg body weight. mosquitoes engorging on drug-treated mice produced the same number of ookinetes as did those fed on controls; drug-fed mosquitoes produced fewer oocysts/mosqu ... | 1990 | 2180334 |
| bifunctional thymidylate synthase-dihydrofolate reductase in protozoa. | protozoa contain thymidylate synthase (ts) and dihydrofolate reductase (dhfr) on the same polypeptide. in the bifunctional protein, the dhfr domain is on the amino terminus, ts is on the carboxyl terminus, and the two domains are separated by a junction peptide of varying size depending on the source. the native protein is composed of a dimer of two such subunits and is 110-140 kda. most studies of the bifunctional ts-dhfr have been performed with the protein from anti-folate resistant strains o ... | 1990 | 2180768 |
| immunogenicity and antigenicity in rabbits of a repeated sequence of plasmodium falciparum antigen pf155/resa fused to two immunoglobulin g-binding domains of staphylococcal protein a. | a synthetic gene encoding a tetramer of the repeated subunit eenvehda of the plasmodium falciparum antigen pf155/resa was expressed in a dual-expression system. the resulting fusion proteins, designated zz-m1 and bb-m1, comprised the eenvehda repeats and either two immunoglobulin g-binding domains from staphylococcal protein a or the human serum albumin-binding domains from streptococcal protein g, respectively. the soluble fusion proteins were affinity purified to homogeneity in one-step proced ... | 1990 | 2180822 |
| falciparum malaria: the current status of antimalarials in therapy and prophylaxis. | | 1990 | 2180891 |
| clindamycin in malaria treatment. | | 1990 | 2180893 |
| the distribution of circumsporozoite protein (cs) in anopheles stephensi mosquitoes infected with plasmodium falciparum malaria. | we monitored the distribution of plasmodium falciparum circumsporozoite protein (cs) in anopheles stephensi using an immunohistochemical method. an alkaline phosphatase-labeled monoclonal antibody, specific for the cs protein of p. falciparum, was incubated with tissue sections from infected and non-infected mosquitoes. sections were stained for phosphatase activity using a new fuchsin/naphthol as-bi phosphate capture system. distribution of the cs protein in mosquitoes was dependent on the time ... | 1990 | 2181019 |
| malaria in leicester 1983-1988: a review of 114 cases. | we have reviewed 114 episodes of malaria in 110 patients who were admitted to the infectious diseases unit in leicester during the 5 year period from february 1983-january 1988. there were 71 episodes of vivax malaria (62%), 33 episodes of falciparum malaria (29%), four patients with mixed infection and six patients with negative blood films who were diagnosed on clinical suspicion alone. most patients presented in the summer months, 68% were aged under 40 years, 39% were born in the indian subc ... | 1990 | 2181023 |
| heterogeneity and expression of the plasmodium falciparum 5.8s ribosomal rna genes. | the number and expression of some of the large ribosomal rna (rrna) gene classes present in the human malaria parasite plasmodium falciparum was determined. southern blot analyses, using the 5.8s rrna coding region as a marker, indicate that the p. falciparum genome contains at least 5 distinct subclasses of large rrna genes. dideoxy sequencing of the 5.8s rrna domain and northern blot analyses demonstrate that only one subclass is transcribed during the parasite's asexual erythrocytic life cycl ... | 1990 | 2181300 |
| association of plasmodium berghei proteins with the host erythrocyte membrane: binding to inside-out vesicles. | two acidic phosphoproteins of plasmodium berghei origin, of 65 and 46 kda, are associated with the plasma membrane of the host mouse erythrocyte. the 65-kda protein partitions between a soluble and particulate phase upon host cell lysis, whereas the 46-kda protein is localized exclusively in the particulate fraction. both proteins bind to inside-out vesicles derived from erythrocyte ghosts and the conditions of the reassociation reaction indicate that the binding is specific and that the protein ... | 1990 | 2181301 |
| conformation and immunogenicity of engineered repeating segment of the circumsporozoite surface protein of plasmodium falciparum. | peptide vaccines based on units of the immunodominant tetrapeptide repeats, asn-ala-asn-pro and asn-val-asp-pro, of the circumsporozoite surface protein of the parasite plasmodium falciparum are presently being developed as potential malaria vaccines. the n-terminal fusion of a hydrophobic protein to units of the tetrapeptide repeat affected the immunogenicity and conformational stability of the peptide, and also induced a secondary structure in the peptide. peptide antigenicity, as well as conf ... | 1990 | 2181302 |
| expression, partial purification and immunogenicity of fragments of the knob protein of plasmodium falciparum. | three structural domains of the histidine-rich knob protein (kp) of plasmodium falciparum were expressed in escherichia coli. a single-step purification scheme was devised to obtain great enrichment of expressed polypeptides for use in subsequent experiments. immune human sera from africa, south-east asia and south america were tested for reactivity with each of the expressed fragments. while the two fragments which represented the central and c-terminal regions of kp showed a strong reactivity ... | 1990 | 2181305 |
| isolation of alpha- and beta-tubulin genes of plasmodium falciparum using a single oligonucleotide probe. | an oligonucleotide probe (315) specific for the alpha- and beta-tubulin genes of plasmodium falciparum was synthesized utilizing codon usage of p. falciparum determined from published gene sequences. by screening genomic and cdna libraries with the oligonucleotide probe, alpha- and beta-tubulin clones were isolated. positive clones were identified by partial sequencing and comparing the deduced amino acid sequence with the chicken brain alpha- and beta-tubulin amino acid sequences. the beta-tubu ... | 1990 | 2181306 |
| structural diversity in the 45-kilodalton merozoite surface antigen of plasmodium falciparum. | an integral membrane protein associated with the merozoite surface of plasmodium falciparum termed merozoite surface antigen 2 (the 45-kda merozoite surface antigen), occurs in antigenically diverse forms. here we report the sequences of the msa 2 gene from two other isolates of p. falciparum. the 43 n-terminal residues and the 74 c-terminal residues of all three msa 2 sequences are highly conserved, but between these conserved regions there are dramatic differences among the alleles. instead of ... | 1990 | 2181307 |
| detection of pyrimethamine resistance in plasmodium falciparum by mutation-specific polymerase chain reaction. | the point mutation at nucleotide 323 within the dihydrofolate reductase-thymidylate synthase gene of plasmodium falciparum, which distinguishes pyrimethamine-sensitive from drug-resistant isolates, can be discriminated by the polymerase chain reaction using mutation-specific primers. the technique makes use of the principle that short oligonucleotides with a perfect match at their 3' ends, complementary to the mutation to be detected, will initiate the polymerization by taq polymerase far more e ... | 1990 | 2181308 |
| apical membrane antigen of plasmodium fragile. | | 1990 | 2181309 |
| sixty-six kilodalton-related antigens of plasmodium knowlesi are merozoite surface antigens associated with the apical prominence. | we have previously reported that fab fragments of a monoclonal antibody to the 66 kd-related antigens of plasmodium knowlesi inhibit merozoite invasion of erythrocytes, strongly suggesting a role for these antigens as merozoite receptors for red cells. in this paper we have examined the distribution of these antigens on the surface of free merozoites. rapid immunofluorescence microscopy on free, unfixed cells demonstrated a preferential association of antigen with a polar region of merozoites. t ... | 1990 | 2181383 |
| consecutive determinations of seroreactivities to pf 155/resa antigen and to its different repetitive sequences in adult men from a holoendemic area of liberia. | sera from 32 adult men residing in a malaria holoendemic area of liberia were investigated for seroreactivities to different asexual blood-stage malaria antigens on five consecutive occasions from 1984 to 1986. the seroreactivities to crude parasitic antigens and to pf 155/resa (emif) were determined by immunofluorescence and to repetitive sequences of pf 155/resa by enzyme-linked immunosorbent assay (elisa). all sera were highly reactive against the crude parasitic antigens with reciprocal titr ... | 1990 | 2181384 |
| malaria in children. | fifty-four cases of malaria in children seen during an 11-year period are described. there have been more cases seen in recent years, and the proportion of plasmodium falciparum malaria has increased. compliance with chemoprophylaxis is poor, but compliance does not guarantee protection. malaria is the primary diagnostic consideration in any child recently returning from an endemic area who presents with fever. two cases are described. | 1990 | 2181413 |
| genetic diversity in plasmodium falciparum. | | 1990 | 2181830 |
| antimalarial action of flavin analogues seems not be due to inhibition of glutathione reductase of host erythrocytes. | a series of 10-(4'-chlorophenyl)-3-substituted flavins (1a-f) were examined with respect to their antimalarial properties. they were tested against plasmodium falciparum in vitro and plasmodium vinckei vinckei in vivo. the proposition that they might act through glutathione reductase (gr) (ec 1.6.4.2) inhibition has been studied. inhibition of p. falciparum in vitro by these compounds shows only slight variation between analogues; in contrast, inhibition of human erythrocyte gr by members of the ... | 1990 | 2182031 |
| [analysis of causes of malaria outbreaks in yunnan province, 1981-1985]. | the incidence of malaria in yunnan province has decreased year by year in recent years. however, focal outbreaks in small scale still occurred every year. the average morbidity in villages with outbreaks was 15.22-70.82%, and the plasmodium positive rate 6.36-34.69%, in which the percentage of plasmodium falciparum 34.55-63.63%. the main cause of outbreaks was the existence of residual source of malaria infection and the concomitance of high density of anopheles. eradication of the vector and er ... | 1990 | 2182195 |
| immune response in patients during and after plasmodium falciparum infection. | the kinetics of indicators of lymphocyte activation were determined in non- and semiimmune patients with uncomplicated plasmodium falciparum infection and in control subjects in acre, brazil. delayed type hypersensitivity (dth) to seven recall antigens was weakest in nonimmune patients. both patient groups differed significantly from controls on admission (p less than .001 for both) and improved considerably after clindamycin therapy. total serum igg and igm, but not antimalarial antibodies, wer ... | 1990 | 2182725 |
| the effect of bacillus sphaericus upon the susceptibility of anopheles quadrimaculatus to plasmodium berghei. | larvae of anopheles quadrimaculatus were exposed to bacillus sphaericus. the surviving adults took blood meals on hamsters infected with plasmodium berghei. fewer mosquitoes were infected than were the paired controls. the inhibitory action appeared to occur during the early stages of the infection in the mosquito gut. | 1990 | 2182774 |
| malaria prophylaxis in travellers to tropical africa. | this study investigated travellers to tropical africa with regard to prophylactic treatment of malaria. a total of 5703 travellers completed a questionnaire on their flights back to the federal republic of germany; 4116 passengers (73.7%) had visited east africa, while 808 (14.5%) had been to west africa. the results indicate that 90.2% took a regular chemoprophylaxis against malaria. nevertheless, 8.1% of the travellers used no antimalarials and in 9.3% chemoprophylaxis was inadequate due to in ... | 1990 | 2182940 |
| organization of subtelomeric repeats in plasmodium berghei. | several (but not all) plasmodium berghei chromosomes bear in the subtelomeric position a cluster of 2.3-kilobase (kb) tandem repeats. the 2.3-kb unit contains 160 base pairs of telomeric sequence. the resulting subtelomeric structure is one in which stretches of telomeric sequences are periodically spaced by a 2.1-kb reiterated sequence. this periodic organization of internal telomeric sequences might be related to chromosome-size polymorphisms involving the loss or addition of subtelomeric 2.3- ... | 1990 | 2183034 |
| purification and characterization of 37-kilodalton proteases from plasmodium falciparum and plasmodium berghei which cleave erythrocyte cytoskeletal components. | cytosoluble 100,000 x g extracts from plasmodium berghei or plasmodium falciparum infected red blood cells were shown to hydrolyze erythrocyte spectrin. by fast protein liquid chromatography (fplc), these enzymes were purified and exhibited a pi of 4.5 and mr of 37,000 using sds-page under reducing conditions. an immunochemical enzyme assay using anti-spectrin antibodies was developed. the optimal activity using spectrin as substrate was at ph 5.0, and the enzymes were strongly inhibited by hgcl ... | 1990 | 2183048 |
| the mature-parasite-infected erythrocyte surface antigen (mesa) of plasmodium falciparum associates with the erythrocyte membrane skeletal protein, band 4.1. | several proteins synthesized by mature asexual stages of plasmodium falciparum interact with the erythrocyte membrane skeleton. one of these is the mature-parasite-infected erythrocyte surface antigen (mesa; also called pfemp2), a phosphoprotein of 250-300 kda, which is found on the internal face of the erythrocyte membrane. when mesa is precipitated with anti-mesa antibodies, another phosphoprotein of 80 kda is co-precipitated. this 80-kda phosphoprotein was identified by peptide mapping as the ... | 1990 | 2183050 |
| homologous sequences in plasmodium cynomolgi and the gene of the histidine-rich knob protein of plasmodium falciparum. | | 1990 | 2183051 |
| nucleotide sequence of the plasmodium berghei circumsporozoite protein gene from the anka clone 2.34l. | | 1990 | 2183186 |
| hemoglobin degradation in the malaria parasite plasmodium falciparum: an ordered process in a unique organelle. | the malaria parasite plasmodium falciparum uses host erythrocyte hemoglobin as a major nutrient source. we report the purification of p. falciparum digestive vacuoles and characterization of the degradative process therein. vacuoles were isolated by a combination of differential centrifugation and density gradient separation. the pure vacuoles were capable of degrading hemoglobin to small fragments with a ph optimum of 5-5.5. proteolysis in the vacuoles appears to be an ordered process, requirin ... | 1990 | 2183218 |
| use of a tuberculin purified protein derivative--asn-ala-asn-pro conjugate in bacillus calmette-guérin primed mice overcomes h-2 restriction of the antibody response and avoids the need for adjuvants. | because of its immunodominancy, and because it is conserved in different geographical isolates of plasmodium falciparum, the repetitive sequence of the circumsporozoite protein, (asn-ala-asn-pro)n [(nanp)n], has been envisaged for the development of an anti-falciparum malaria subunit vaccine. however, the murine immune response to (nanp)n peptides, either carrier-free or coupled to carrier proteins, was shown to be inducible only by using strong (e.g., freund's) adjuvants. furthermore, response ... | 1990 | 2183219 |
| amino acids in the dihydrofolate reductase-thymidylate synthase gene of plasmodium falciparum involved in cycloguanil resistance differ from those involved in pyrimethamine resistance. | cycloguanil, the active metabolite of the antimalarial drug proguanil, is an inhibitor of dihydrofolate reductase as is another antimalarial, pyrimethamine. its use has been limited by the rapid development of resistance by parasites around the world. we have determined the cycloguanil- and pyrimethamine-sensitivity status of 10 isolates of plasmodium falciparum and have sequenced in all these isolates the dihydrofolate reductase (dhfr; 5,6,7,8-tetrahydrofolate: nadp+ oxidoreductase, ec 1.5.1.3) ... | 1990 | 2183221 |
| molecular basis of differential resistance to cycloguanil and pyrimethamine in plasmodium falciparum malaria. | proguanil and pyrimethamine are antifolate drugs with distinct chemical structures that are used commonly in the prophylaxis and treatment of plasmodium falciparum malaria. clinical reports and field studies have suggested that some parasites refractory to proguanil can be treated with pyrimethamine, and vice versa. analysis of the p. falciparum dihydrofolate reductase (dhfr) from different parasites reveals the structural basis for differential susceptibility to these antifolate drugs. parasite ... | 1990 | 2183222 |
| increased nicotinamide adenine dinucleotide content and synthesis in plasmodium falciparum-infected human erythrocytes. | plasmodium falciparum-infected red blood cells (rbcs) are characterized by increases in the activity of glycolytic enzymes. because nicotinamide adenine dinucleotide (nad) and nad phosphate (nadp) are cofactors in the reactions of glycolysis and pentose phosphate shunt, we have examined nad and nadp content in p. falciparum-infected rbcs. although nadp content was not significantly altered, nad content was increased approximately 10-fold in infected rbcs (66% parasitemia) compared with uninfecte ... | 1990 | 2183889 |
| treatment of malaria--1990. | malaria has become an increasingly common health problem in the 1970s and 1980s, both in areas where infection is endemic and in travellers returning to non-endemic areas. the severity of infection varies widely, depending on the plasmodial species involved, and there is an extensive chemotherapeutic armamentarium currently available to combat malarial infection. drug chemistry, pharmacokinetics, mechanism of drug action and resistance, and toxicities are outlined for the cinchona alkaloids (qui ... | 1990 | 2183998 |
| prevention of malaria. | with the increased spread of chloroquine-resistant plasmodium falciparum malaria and mounting evidence of lack of efficacy and toxicity of alternative drugs, it has become extremely difficult to propose simple, widely applicable and uniformly acceptable recommendations for malaria chemoprophylaxis. with regard to specific drugs, it is clear that because of its toxicity amodiaquine should no longer be used for chemoprophylaxis, and that pyrimethamine/sulfadoxine should, for the most part, be used ... | 1990 | 2184005 |
| initiation of translation at a uag stop codon in the aldolase gene of plasmodium falciparum. | the gene coding for the key glycolytic enzyme fructose-1,6-diphosphate aldolase of the human malaria parasite plasmodium falciparum lacks a functional aug initiation codon for translation. protein sequences of natural or in vitro translated aldolase include the candidate start methionine residue at internal positions. no additional aug start codon is found in genomic dna, cdna or mrna sequences. instead, a uag chain termination codon is recognized as the start signal of protein synthesis in vivo ... | 1990 | 2184034 |
| [nutritional status in children under 6 years of age and its relation to malaria and intestinal parasitism]. | in order to determine the prevalence of the nutritional situation in children under six years of age and to study the relation with malaria and intestinal parasitism an epidemiological study of a cross sectional was carried out in cordoba locality, buenaventura municipality in the colombian pacific coast. one hundred and twenty eight children were studied to whom a questionnaire, a thick smear examination, and a serological test through the indirect immunofluorescence reaction was practiced. cop ... | 1990 | 2184526 |
| characteristics of malaria transmission in kataragama, sri lanka: a focus for immuno-epidemiological studies. | parasitological and entomological parameters of malaria transmission were monitored for 17 months in 3,625 residents in a plasmodium vivax malaria endemic region in southern sri lanka; the study area consisted of 7 contiguous villages where routine national malaria control operations were being conducted. malaria was monitored in every resident; fever patients were screened and 4 periodical mass blood surveys were conducted. an annual malaria incidence rate of 23.1% was reported during the perio ... | 1990 | 2184688 |
| differences in susceptibility among mouse strains to infection with plasmodium berghei (anka clone) sporozoites and its relationship to protection by gamma-irradiated sporozoites. | three inbred mouse strains, c57bl/6 (h-2b), a/j (h-2a), and balb/c (h-2d), and 1 outbred strain, cd-1, demonstrated differences in susceptibility to iv challenge with the anka clone of plasmodium berghei. mice were challenged with 100, 1,000, or 10,000 sporozoites, then evaluated daily beginning on day 4 for patency. cd-1 mice were further evaluated at challenge doses of 12,500, 25,000, and 50,000 sporozoites. c57bl/6 mice were the easiest to infect, with 90% becoming infected with 100 sporozoit ... | 1990 | 2184689 |
| a rapid sporozoite elisa using 3,3',5,5'-tetramethylbenzidine as the substrate chromogen. | a modified version of the standard 2-site sporozoite enzyme-linked immunosorbent assay (elisa) using 3,3',5,5'-tetramethylbenzidine (tmb) as the substrate chromogen solution was adapted for rapid detection and identification of plasmodium falciparum and p. vivax circumsporozoite (cs) proteins. the tmb-elisa was evaluated using sporozoites from experimentally infected mosquitoes and laboratory colonized uninfected mosquitoes. our data indicate comparable sensitivity levels between the tmb-elisa a ... | 1990 | 2184690 |
| failure of chloroquine prophylaxis for falciparum malaria in pregnant women in madang, papua new guinea. | six hundred and twenty pregnant women, living under conditions of year-round transmission of malaria in a rural coastal area of madang, papua new guinea (png), were followed while attending mobile antenatal clinics and receiving chloroquine prophylaxis (300 mg base weekly). whole blood chloroquine concentrations measured by elisa from samples collected at delivery indicated a high level of drug compliance in regular attenders. susceptibility is increased in primigravidae to plasmodium falciparum ... | 1990 | 2184784 |
| consequences of maternal anaemia on outcome of pregnancy in a malaria endemic area in papua new guinea. | the prevalence of anaemia during pregnancy was investigated in relation to parasite and spleen rates of pregnant women living in a defined study area in rural madang, papua new guinea. the effects in pregnancy of anaemia, iron deficiency and malaria on the foetus were investigated. there is a high prevalence of anaemia in this population, with 44% of primigravidae and 29% of multigravidae having severe anaemia [haemoglobin (hb) less than 8 g dl-1] after 28 weeks gestation. the odds ratio for sev ... | 1990 | 2184786 |
| infectivity of gametocytes of plasmodium falciparum and plasmodium vivax after storage in vitro. | | 1990 | 2184788 |
| pulmonary edema in severe falciparum malaria. hemodynamic study and clinicophysiologic correlation. | this study was performed to extend the knowledge of the pathogenesis of pe in severe falciparum malaria. sequential hemodynamic studies were conducted in 13 patients with severe falciparum malaria. seven patients developed pe, while the other six patients had npe. two patients died, one in each group. hemodynamic changes were found in both groups, including an initial reduction in svr and pvr, along with an increased ci and variable values (normal and increased) of pcwp. all abnormalities persis ... | 1990 | 2184996 |
| in vitro responses of human peripheral blood mononuclear cells to plasmodium falciparum antigen. | immunity to malaria involves cell-mediated and humoral responses. the cell-mediated reaction is thought to focus particularly on the activity of cells of the macrophage lineage. the ability of antigen-stimulated human peripheral blood lymphocytes to undergo proliferation and produce factors capable of causing macrophage inhibition of parasite growth has been examined. while lymphocyte proliferation, gamma-interferon production, and anti-malarial antibody levels of malaria-exposed papua new guine ... | 1990 | 2185169 |
| [new antimalarial sustained-release formulations based on bioresorbable polymers: therapeutic evaluation using the plasmodium berghei model]. | chemotherapy keeps an important place in malaria control programme. the development of schizonticidal formulations, which may maintain their efficacy for at least one month after single administration, becomes needful. these formulations should allow to assure a suitable patient compliance and to avoid the disadvantages of high plasmatic peaks. the aim of this study is to evaluate the therapeutic efficacy of implantable bioresorbable reservoir-forms. the use of these polymers allow to avoid the ... | 1990 | 2185357 |
| malaria sporozoite detection by dissection and elisa to assess infectivity of afrotropical anopheles (diptera: culicidae). | malaria infection rates determined by dissection and plasmodium falciparum enzyme-linked immunosorbent assay (elisa) were compared for 26,935 anopheles gambiae giles sensu lato and 17,739 anopheles funestus giles collected during 20 mo in western kenya. elisa infection rates were about 43% higher than dissection sporozoite rates. in dissection-negative anopheles, circumsporozoite (cs) protein was detected by elisa in 5.2% of 10,017 salivary gland samples and in 12.2% of 237 thorax samples. the a ... | 1990 | 2185363 |
| long struggle continues to find new weapons against an old foe--the malaria parasite. | | 1990 | 2185370 |
| malaria: the path of drug resistance. | | 1990 | 2185423 |
| several alleles of the multidrug-resistance gene are closely linked to chloroquine resistance in plasmodium falciparum. | the lethal form of human malaria caused by plasmodium falciparum is virtually uncontrollable in many areas because of the development of drug resistance, in particular chloroquine resistance (cqr). cqr is biologically similar to the multiple drug resistance phenotype (mdr) of mammalian tumour cells, as both involve expulsion of drug from the cell and both can be reversed by calcium channel antagonists. a homologue (pfmdr1) of the mammalian multidrug resistance gene has been implicated in cqr bec ... | 1990 | 2185424 |
| increased plasma lipid peroxidation in riboflavin-deficient, malaria-infected children. | plasma lipid peroxides were measured as malonyldialdehyde (mda) by the thiobarbituric acid (tba) method in 75 children suffering from plasmodium falciparum malaria. their riboflavin status was assessed by measuring erythrocyte glutathione reductase activation coefficients (egracs), and values greater than 1.40 were regarded as indicating biochemical deficiency. plasma mda was higher (p less than 0.001) in patients than in control subjects; the concentrations were 3.65 +/- 0.70 and 1.77 +/- 0.45 ... | 1990 | 2185624 |
| antimalarial activity of substituted anthraquinones. | | 1990 | 2186725 |
| multiple-dose kinetics in healthy volunteers and in vitro antimalarial activity of proguanil plus dapsone. | the multiple-dose kinetics of a daily dose of proguanil (200 mg) coadministered with dapsone (10 mg) was investigated in 6 healthy adult male volunteers. the kinetics of dapsone (dds), monoacetyldapsone (madds), proguanil (prog) and its active metabolite cycloguanil (cyclo) were derived from plasma drug concentrations after the last maintenance dose. the following kinetic parameters (mean values) were estimated for dds and prog, respectively: maximum concentration (cmax) = 285 and 151 ng/ml, min ... | 1990 | 2186899 |
| antimalarial activity of the ethanol/alcohol oxidase system in vitro. | among other macrophage secretory products, h2o2 plays an important role in the host's defense against malaria (wozencraft et al., infect. immun., 43, 664, (1984]. in our in vitro studies on the human malaria parasite plasmodium falciparum, hydrogen peroxide was produced by the alcohol oxidase-catalyzed reaction ethanol + o2----acetaldehyde + h2o2 (ec 1.1.3.13). at concentrations of 8.7 mm (= 0.5%) ethanol and 0.1 u alcohol oxidase per ml culture, more than 95% of the parasites were irreversibly ... | 1990 | 2186976 |
| [antimalarial chemoprophylaxis in pregnancy]. | the drugs available for malaria chemoprophylaxis in pregnancy and their posology, side-effect in pregnant women and foetus are analyzed particularly for areas of high multidrug resistance. chloroquine and proguanil are the most used with few side-effects, while pyrimethamine is recommended only for chloroquine-resistant plasmodium falciparum spp. | 1990 | 2187165 |
| immunization of aotus monkeys with plasmodium falciparum blood-stage recombinant proteins. | the current spread of multidrug-resistant malaria demands rapid vaccine development against the major pathogen plasmodium falciparum. the high quantities of protein required for a worldwide vaccination campaign select recombinant dna technology as a practical approach for large-scale antigen production. we describe the vaccination of aotus monkeys with two recombinant blood-stage antigens (recombinant p41 and 190n) that were considered as vaccine candidates because parasite-derived antigen prepa ... | 1990 | 2187200 |