| cloning and characterization of chromosome breakpoints of plasmodium falciparum: breakage and new telomere formation occurs frequently and randomly in subtelomeric genes. | we analysed the genetic stability of two subtelomeric genes of the human malaria parasite plasmodium falciparum. a pcr based assay, using a telomere and a target-gene specific primer was used to detect potential chromosome rearrangements. we show that chromosome breakage and the formation of new telomeres occur frequently in the two genes coding for histidine rich proteins (hrp i and hrp ii) in laboratory isolates, but remains undetectable in clinical parasite isolates. this finding suggests an ... | 1992 | 1579440 |
| [self-medication of 193 travelers in the tropics. recommendations for clinical counseling of tropical travelers and organization of a tropical travel pharmacy]. | medical advice for the traveller is of increasing importance since in the past decade in industrialized countries there is a steady increase in numbers of travellers and distance travelled. self medication was evaluated in 193 travellers to malaria-endemic areas. diarrhoea, fever and headache were the most frequent symptoms. antidiarrhoeal agents, analgetics/antipyretics, antibiotics and oral contraceptives were the drugs most often used by travellers. one case of mefloquine-resistant and chloro ... | 1992 | 1580072 |
| cerebral malaria from plasmodium falciparum. a clinical report. | | 1992 | 1580207 |
| treatment of severe falciparum malaria during pregnancy with quinidine and exchange transfusion. | malaria during pregnancy may be associated with significant morbidity and mortality in both mother and fetus. treatment of severe chloroquine-resistant malaria during pregnancy may be problematic since quinine and related compounds may have a deleterious effect on the course of labor. this article reports the case of a 21-year-old primigravida liberian woman who presented with high-grade (greater than 12%) parasitemia with plasmodium falciparum. the patient was initially treated with chloroquine ... | 1992 | 1580303 |
| positive selection and interallelic recombination at the merozoite surface antigen-1 (msa-1) locus of plasmodium falciparum. | dna sequences of alleles at the merozoite surface antigen-1 (msa-1) gene locus of the malaria parasite plasmodium falciparum show evidence of repeated past recombination events between alleles. these include both (1) nonreciprocal recombination events that have homogenized certain gene regions among alleles and (2) reciprocal recombination events that have combined allelic segments with divergent evolutionary histories, thereby enhancing allelic diversity. in three different gene regions, the ra ... | 1992 | 1584009 |
| a module of the dnaj heat shock proteins found in malaria parasites. | | 1992 | 1585456 |
| cytoadherence and ultrastructure of plasmodium falciparum-infected erythrocytes from a splenectomized patient. | in malarial infections of primates, the spleen has been shown to modulate parasite antigen expression on the surfaces of infected erythrocytes. the processes affected include cytoadherence, which is central to the pathophysiology of severe falciparum malaria, and the related phenomenon of rosette formation. in this study, the cytoadherence and rosette formation behaviors of plasmodium falciparum-infected erythrocytes from a splenectomized patient were examined during the first erythrocytic cycle ... | 1992 | 1587590 |
| protection of aotus monkeys from malaria infection by immunization with recombinant hybrid proteins. | on the basis of investigations of the malarial blood-stage antigens serp, hrpii, and msai from plasmodium falciparum, we chose two escherichia coli-expressed hybrid proteins containing selected partial sequences of these antigens. antibodies raised against both hybrid proteins in rabbits and aotus monkeys recognize the corresponding p. falciparum polypeptides. in two independent trials with 13 animals, immunization of aotus monkeys with either of the two hybrid proteins administered in a well-to ... | 1992 | 1587607 |
| mitochondrial function in babesia bovis. | a variety of anti-mitochondrial drugs that had previously been found to inhibit the growth of the malarial parasite plasmodium falciparum were tested on babesia bovis in vitro. several of these drugs were found to be non-toxic towards b. bovis. however, those drugs that were found to inhibit babesial growth included compounds (shown in parentheses) that have the following putative mitochondrial targets in the parasite: atp synthetase complex (rhodamine 123, oligomycin, janus green); atp-adp tran ... | 1992 | 1587679 |
| absence of effect of retinol on the in vitro development of plasmodium falciparum. | | 1992 | 1587714 |
| codon usage in pathogenic entamoeba histolytica. | | 1992 | 1588599 |
| population genetics and dynamics of plasmodium falciparum: an ecological view. | molecular characterization of the plasmodium falciparum genome has led to identification of polymorphic loci and the mechanisms generating genetic diversity in this parasite. this information has resulted in the development of molecular methods to type parasite diversity in the field. consequently, we are now in a position to describe the population genetics and dynamics of p. falciparum. the limited number of field studies that have been conducted to date have revealed an extraordinary degree o ... | 1992 | 1589299 |
| in vitro activities of chloroquine in combination with chlorpromazine or prochlorperazine against isolates of plasmodium falciparum. | the combinations of chloroquine plus chlorpromazine and chloroquine plus prochlorperazine were evaluated in vitro for potentiation against isolates of plasmodium falciparum. potentiation was observed against all chloroquine-resistant isolates. there was no potentiation against 8 of 10 chloroquine-susceptible isolates. the results indicated that the phenothiazines can potentiate chloroquine action against resistant parasites found in natural conditions. | 1992 | 1590691 |
| use of radioactive ethanolamine incorporation into phospholipids to assess in vitro antimalarial activity by the semiautomated microdilution technique. | phospholipid biosynthetic activity is intense in the erythrocytic stage of plasmodium falciparum because of the parasite's own enzymatic machinery. the incorporation of various labeled phospholipid precursors in comparison with the incorporation of nucleic acid and protein precursors was tested to evaluate p. falciparum growth in vitro. these precursors, namely, [3h]ethanolamine, [3h]hypoxanthine, [3h]palmitate, [14c]serine, [3h]choline, [3h]inositol, and [3h]isoleucine, were all accurate indica ... | 1992 | 1590699 |
| plasmodium falciparum: the repetitive msa-1 surface protein of the ro-71 isolate is recognized by mouse antibody against the nonrepetitive repeat block of ro-33. | we have expressed in escherichia coli the nonrepetitive repeat zone of the msa-1 surface protein of the ro-33 isolate of plasmodium falciparum. the recombinant protein was used to immunize mice and the resulting ro-33 monospecific serum was used to screen our p. falciparum strain collection in order to recover additional alleles lacking tripeptide repeats in block 2 of msa-1. only 1 (ro-71) out of 30 isolates tested reacted strongly with the serum by indirect immunofluorescence assay. surprising ... | 1992 | 1592091 |
| eimeria tenella: growth and drug sensitivity in tissue culture under reduced oxygen. | for plasmodium falciparum in culture, growth is enhanced as oxygen tension is lowered and drug susceptibility, particularly susceptibility to 70s ribosomal and mitochondrial inhibitors, changes. whether similar effects occur in eimeria tenella was tested as a possible explanation for why certain 70s ribosomal inhibitors, while active in eimeria-infected birds, are virtually inactive in vitro under ambient oxygen conditions. it was reasoned that perhaps these agents would exhibit good in vitro po ... | 1992 | 1592094 |
| plasmodium falciparum: rapid detection of dihydrofolate reductase mutations that confer resistance to cycloguanil and pyrimethamine. | | 1992 | 1592095 |
| relationship between body size of adult anopheles gambiae s.l. and infection with the malaria parasite plasmodium falciparum. | the influence of adult female body size of anopheles gambiae s.l. on development of midgut and salivary gland infections by the parasite plasmodium falciparum was investigated in a field study carried out in tanzania. the proportion of mosquitoes infected during a blood meal was independent of size. however, the number of oocysts harboured by infected mosquitoes increased with size of the mosquito. the proportion of mosquitoes with sporozoites, and thus potentially infective to humans, was highe ... | 1992 | 1594289 |
| membrane proteins involved in the adherence of plasmodium falciparum-infected erythrocytes to the endothelium. | plasmodium falciparum (human malaria) infections are characterized by the attachment of erythrocytes infected with mature stage parasites to endothelial cells lining the post-capillary venules, a phenomenon known as sequestration. in the human body, the microvessels of the heart, lungs, kidneys, small intestine, and liver are the principal sites of sequestration. sequestered cells that clog the brain capillaries may reduce blood flow sufficiently so that there is confusion, lethargy, and unarous ... | 1992 | 1596638 |
| an overview of molecular parasitology in china. | molecular cloning technology has been gradually used in the studies of parasitic diseases in china since 1986. the information briefly reviewed here deals mainly with: (1) the molecular cloning of immunogen genes related to schistosome and plasmodium; (2) a diagnostic dna probe for malaria and toxoplasmosis; and (3) dna probes for inter- and intra-specific differentiation of leishmania, schistosome, entamoeba, etc. | 1992 | 1597082 |
| [spontaneous splenic rupture in acute malaria tropica]. | a 44-year-old man developed bouts of fever (up to 40 degrees c) seven days after returning from a holiday in kenya. malaria prophylaxis with chloroquine had been correctly undertaken. concentrations of lactate dehydrogenase and total bilirubin were raised (493 u/l and 3.55 mg/dl, respectively). blood smear revealed the ring forms of plasmodium falciparum. thereupon the patient was given mefloquine in decreasing doses (750/500/250 mg) at intervals of 8 hours. the following night he had a circulat ... | 1992 | 1597109 |
| bisquinolines. 1. n,n-bis(7-chloroquinolin-4-yl)alkanediamines with potential against chloroquine-resistant malaria. | on the basis of observations that several bisquinolines such as piperaquine possess notable activity against chloroquine-resistant malaria, 13 n,n-bis-(7-chloroquinolin-4-yl)alkanediamines were synthesized and screened against plasmodium falciparum in vitro and plasmodium berghei in vivo. twelve of the thirteen bisquinolines had a significantly lower resistance index than did chloroquine; the resistance index was apparently unrelated to either in vitro or in vivo activity. except for two compoun ... | 1992 | 1597862 |
| case-control studies of severe malaria. | the majority of children infected with plasmodium falciparum in areas of stable endemicity do not develop severe, life-threatening disease. it is important to identify risk factors for the minority who do. case-control studies in which children with severe disease are compared with children with non-severe disease and with community controls, avoid some of the ethical and logistical problems inherent in such an undertaking. this paper discusses methodological aspects of case-control studies of s ... | 1992 | 1597871 |
| malaria and pregnancy in cameroonian women. effect of pregnancy on plasmodium falciparum parasitemia and the response to chloroquine. | the interaction between malaria and pregnancy was investigated in an epidemiologic study conducted in mfou, a rural community in cameroon. the study consisted of both cross-sectional and longitudinal analyses involving 225 pregnant women and 75 nonpregnant controls. information was obtained by a standardized questionnaire to determine the pattern of antimalarial drug use. the parasitologic response to chloroquine was also determined. a dosage of chloroquine base (25 mg/kg of body weight) was giv ... | 1992 | 1598501 |
| experiments on cryopreservation of plasmodium falciparum. | a comparative study was carried out in order to assess the effectivity of the deep-freezing conditions for p. falciparum cultures: 1. by plunging them into liquid nitrogen, 2. by use of an established freezing program for lymphocytes. after thawing in a waterbath at 37 degrees c, samples were diluted with equal volumes of 3.5% sodium chloride solution or 15% phosphate-buffered saline supplemented glucose solution. other samples were not diluted after thawing, but the medium was replaced twice du ... | 1992 | 1598502 |
| the effects of ascorbate-induced free radicals on plasmodium falciparum. | ascorbic acid has been shown to cause stage-dependent effects on the in vitro development of plasmodium falciparum. while vitamin c marginally enhanced the development of young parasites, it proved highly destructive to the advanced forms. the present study evaluates the mechanisms by which vitamin c affects the parasite. the treatment of parasitized erythrocytes with ascorbate resulted in the conversion of added salicylate to dihydroxybenzoate products, indicating the involvement of hydroxyl ra ... | 1992 | 1598503 |
| the incidence of pulmonary manifestations during plasmodium falciparum malaria in non immune subjects. | the incidence of clinical pulmonary manifestations during clinically mild plasmodium falciparum malaria was studied in 50 patients. in nine patients (18%), respiratory symptoms developed and consisted of cough either productive (in 5) or dry and pleuritic (in 3), wheezing and dyspnea (in 2). physical examination of these patients disclosed minimal decrease of breath sounds with diffuse moist rales over both lung bases. chest x-rays showed small infiltrates and increased vascular markenings in mo ... | 1992 | 1598511 |
| the effect of splenectomy on immunity to plasmodium malariae and p. falciparum in a malaria immune donor. | a 55 year old liberian male was splenectomized after an abdominal trauma. a few days after splenectomy he experienced a pure plasmodium malariae infection with high fever. he was later followed for 12 months with monthly blood films and temperature measurements, and did never show any signs of clinical malaria. the parasite densities observed during the longitudinal follow after splenectomy did not differ from parasite densities in villagers with intact spleens. | 1992 | 1598514 |
| an inexpensive and simple method for screening potential antimalarial drugs. | the visual in vitro test proved to be a very useful tool for screening a series of 54 chemical analogues for their antimalarial activity. the test relies on the formation of dark pigment precipitates after an alkaline solution is added to synchronous cultures of plasmodium falciparum. pigment is produced when a chemical compound is unable to prevent the maturation of rings to schizonts during incubation. however, in the presence of effective concentrations of a compound, maturation is inhibited ... | 1992 | 1598517 |
| segregation analysis detects a major gene controlling blood infection levels in human malaria. | the profound influence that the genetic makeup of the host has on resistance to malaria infection has been established in numerous animal studies. this genetic heterogeneity is one of the main causes of the difficulties in developing an effective malaria vaccine. segregation analysis is the first step in identifying the nature of genetic factors involved in the expression of human complex diseases, as infectious diseases. to assess the role of host genes in human malaria, we performed segregatio ... | 1992 | 1598911 |
| rosette formation in plasmodium falciparum isolates and anti-rosette activity of sera from gambians with cerebral or uncomplicated malaria. | the ability of plasmodium falciparum-infected red blood cells (rbc) to form spontaneous erythrocyte rosettes was studied in 130 fresh isolates from gambian children with cerebral or uncomplicated malaria from august to november 1990. all isolates (24 of 24) from patients with cerebral malaria formed rosettes, but only 61 of 106 isolates from children with uncomplicated malaria formed rosettes. the mean rate of rosette formation in isolates from children with cerebral malaria (28.3%) was signific ... | 1992 | 1599043 |
| ultrastructural analysis of fresh plasmodium falciparum-infected erythrocytes and their cytoadherence to human leukocytes. | sixty fresh plasmodium falciparum isolates obtained from gambian children with mild or cerebral malaria were investigated by transmission electron microscopy for the expression of knob-like protrusions (k+) on the surface of the infected erythrocytes. more than six-hundred infected erythrocytes were analyzed. knob-forming parasites were present in all 60 isolates. although knobless parasites (k-) were found in 25 (42%) of the isolates, only 39 were k-, while 577 were k+. nine of the 39 k- infect ... | 1992 | 1599044 |
| effect of different fractions of heparin on plasmodium falciparum merozoite invasion of red blood cells in vitro. | heparin and various heparin fractions were separated according to differences in molecular weight or affinity for antithrombin iii and used for the inhibition of plasmodium falciparum merozoite invasion of red blood cells in vitro. no variation in sensitivity to heparin was found among the four strains of p. falciparum tested; all required approximately 5 micrograms/ml (0.5 u/ml) of heparin for 50% inhibition of invasion. the most efficient fraction of heparin was the one with low affinity for a ... | 1992 | 1599053 |
| disruption of plasmodium falciparum erythrocyte rosettes by standard heparin and heparin devoid of anticoagulant activity. | we have studied the ability of heparin to disrupt spontaneous rosettes formed between plasmodium falciparum-infected and uninfected red blood cells, which has been proposed to have importance in the pathogenesis of cerebral malaria. substantial variation in this activity was found among six laboratory stains of p. falciparum. rosettes formed by three of these strains were highly sensitive to heparin (50% disruption at 0.5-25 micrograms/ml; 1 microgram/ml corresponds to 0.15 iu/ml). the rosettes ... | 1992 | 1599054 |
| malaria vaccines. | | 1992 | 1600390 |
| gene inactivation of pf11-1 of plasmodium falciparum by chromosome breakage and healing: identification of a gametocyte-specific protein with a potential role in gametogenesis. | we report the identification of the product of the plasmodium falciparum pf11-1 gene and demonstrate that it is a gametocyte-specific protein that has a potential role in the rupture of the host erythrocyte and emergence of the gametes (gametogenesis). the pf11-1 gene is a large locus (30 kb) whose sequence predicts a glutamic acid-rich polypeptide. our identification of the pf11-1 gene product as gametocyte specific was greatly facilitated by the isolation of a mutant parasite clone in which gr ... | 1992 | 1600948 |
| incidence of hypoglycaemia in children with severe plasmodium falciparum malaria around rourkela, orissa state. | to determine the incidence of hypoglycaemia in children suffering from severe falciparum malaria, 23 patients from rourkela (orissa), were investigated. plasma glucose and immunoreactive insulin were estimated before and at hourly intervals during quinine infusion. no child had hypoglycaemia at the time of admission. correlation between parasite count and prequinine plasma glucose was not significant. in the period of quinine infusion, 20 patients showed fall in plasma glucose during all the thr ... | 1992 | 1601475 |
| treatment of malaria acquired in southeast asia. | | 1992 | 1603377 |
| il-4 inhibits macrophage-mediated killing of plasmodium falciparum in vitro. a possible parasite-immune evasion mechanism. | although a number of mechanisms have been put forward for immunity to malaria, their importance remains to be clarified. one of the important findings is that nonactivated monocytes and macrophages showed marked antiplasmodial activity in vitro. recently we postulated that parasites may induce host factors that may depress the natural antiplasmodial activity of monocytes. in this investigation we identify il-4 as a lymphokine that could function in this capacity. human monocytes and macrophages ... | 1992 | 1607652 |
| safety and immunogenicity of the synthetic malaria vaccine spf66 in a large field trial. | in the first field trial with synthetic malaria vaccine spf66 in a large population naturally exposed to malaria, 9957 persons greater than 1 year old and residing on the colombian pacific coast received three doses of the vaccine. to evaluate vaccine safety, clinical observations were made 30 min and 48 h after each immunization. there were no adverse reactions in 95.7% of cases. in the 4.3% of cases with adverse reactions, local induration and erythema were the most frequent. in a randomly sel ... | 1992 | 1607685 |
| detection of plasmodium falciparum by polymerase chain reaction in a field study. | detection of plasmodium falciparum by polymerase chain reaction (pcr) was evaluated in 33 p. falciparum-infected patients with two different amplification systems over 5-7 days of curative treatment. in the k1-14 system, a p. falciparum dna fragment of 206 bp was detected, and in the circumsporozoite (cs) system, a fragment of 800 bp was detected. the k1-14 and cs systems identified 95% and 93%, respectively, of 103 microscopically identified specimens; both systems detected as few as 11 parasit ... | 1992 | 1607686 |
| evaluation of the in vitro antimalarial activity of picralima nitida extracts. | extracts of picralima nitida seeds, fruit rind, and stem bark have been investigated in vitro for antimalarial activity. the extracts showed remarkable inhibitory activity against drug resistant clones of plasmodium falciparum at doses of 1.23-32 micrograms/ml. the dichloromethane extract of the fruit rind was the most active of the crude extracts, with ic50 values of 1.61 micrograms/ml for the indochina (w-2), clone and 2.41 micrograms/ml for the sierra leone (d-6), clone. an alkaloid fraction ... | 1992 | 1608269 |
| survey of medicinal plants used as antimalarials in the amazon. | plants traditionally employed for the treatment of malaria in certain areas of brazil, where this disease is prevalent, were surveyed by interviewing natives and migrants in the amazon region. forty-one plants used for malarial treatment and/or for the related symptoms (fever and liver disorders) were collected and identified. given the potential of brazil's forests and medicinal plants, research on traditional plant-based remedies in this country may lead to the development of new drugs. | 1992 | 1608275 |
| extracellular (axenic) development in vitro of the erythrocytic cycle of plasmodium falciparum. | merozoites of the erythrocytic stage of plasmodium falciparum were suspended in erythrocyte sonicate medium with atp and pyruvate and mixed with matrigel to form a soft gel. the gel was overlaid with complete medium; this was replaced with fresh medium at 12, 24, and 36 hr. at these times and also at 45 hr rhodamine 123 was added to some cultures and gels were sampled. viable extracellular forms showing rhodamine fluorescence were seen: rings at 12 hr, trophozoites and early schizonts with pigme ... | 1992 | 1608943 |
| merocyanine 540-sensitized photoinactivation of human erythrocytes parasitized by plasmodium falciparum. | the purpose of this study was to evaluate the photosensitizing dye merocyanine 540 (mc540) as a means for extracorporeal purging of plasmodium falciparum-infected erythrocytes from human blood. parasitized red blood cells bound more dye than nonparasitized cells, and exposure to mc540 and light under conditions that are relatively well tolerated by normal erythrocytes and normal pluripotent hematopoietic stem cells reduced the concentration of parasitized cells by as much as 1,000-fold. cells pa ... | 1992 | 1611086 |
| malaria. asexual deviants take over. | | 1992 | 1614513 |
| rapid switching to multiple antigenic and adhesive phenotypes in malaria. | adhesion of parasitized erythrocytes to post-capillary venular endothelium or uninfected red cells is strongly implicated in the pathogenesis of severe plasmodium falciparum malaria. neoantigens at the infected red-cell surface adhere to a variety of host receptors, demonstrate serological diversity in field isolates and may also be a target of the host-protective immune response. here we use sequential cloning of p. falciparum by micromanipulation to investigate the ability of a parasite to swi ... | 1992 | 1614515 |
| cerebral malaria. | cerebral malaria is the most important manifestation of severe plasmodium falciparum infection. the clinical picture in south east asian adults differs from that in african children. the children are more likely to have abnormal brain stem reflexes, signs suggestive of cerebral herniation, and raised csf opening pressure, and to suffer persistent neurological sequelae. the mortality remains high at about 20%. the diagnosis must be considered in all patients with fever and impaired consciousness ... | 1992 | 1615297 |
| extraordinarily potent antimalarial compounds: new, structurally simple, easily synthesized, tricyclic 1,2,4-trioxanes. | new, racemic, tricyclic trioxane alcohol 3 was designed and synthesized as a structurally simple analog of clinically useful, tetracyclic, antimalarial artemisinin. a series of 20 ester and ether derivatives of alcohol 3 were prepared easily, without destruction of the essential trioxane system. chemical structure-antimalarial activity for each derivative was evaluated in vitro against chloroquine-resistant and chloroquine-sensitive plasmodium falciparum parasites. many of these derivatives were ... | 1992 | 1619620 |
| pyrimethamine resistant mutations in plasmodium falciparum. | three mutations in plasmodium falciparum yielding increased resistance to pyrimethamine were obtained following treatment with chemical mutagens and selection in presence of pyrimethamine. from parasite clone tm4/8.2 a mutant, tm4/8.2/4.1, was produced which raised pyrimethamine resistance about 500 times and was found to involve an amino acid change in the dhfr-ts enzyme molecule from ser108 to asn108. a clone of another isolate, t9/94, yielded a mutant, t9/94/300.300, raising pyrimethamine res ... | 1992 | 1620155 |
| p-aminobenzoic acid transport by normal and plasmodium falciparum-infected erythrocytes. | de novo folate biosynthesis is required for the growth of malarial parasites and is inhibited by several important antimalarial agents. we show here that exogenous p-aminobenzoic acid (paba) can be utilized by malaria parasites to synthesize folates. the transport of paba into parasite infected red cells was therefore characterized. normal red cells transport paba in a saturable and energy-dependent manner, with a dissociation constant of 83 nm. paba transport in parasite-infected red cells may ... | 1992 | 1620158 |
| synthesis and secretion of proteins by released malarial parasites. | controlled mechanical homogenization of plasmodium falciparum-infected erythrocytes releases parasites of a quality sufficient for studying the export of newly synthesized plasmodial proteins. protein synthesis occurs within intact released parasites as defined by resistance of acid-insoluble incorporation of radiolabel to high levels of exogenously added edta, hexokinase, and rnasea. while exogenously added atp and erythrocyte cytosol were not essential for biosynthetic activity at levels compa ... | 1992 | 1620161 |
| isolation of skeleton-associated knobs from human red blood cells infected with malaria parasite plasmodium falciparum. | | 1992 | 1620167 |
| a sequence element associated with the plasmodium falciparum kahrp gene is the site of developmentally regulated protein-dna interactions. | the plasmodium falciparum gene encoding the knob associated histidine-rich protein (kahrp) is shown to be transcriptionally regulated during its expression in the intraerythrocytic cycle as demonstrated by stage specific nuclear run-on analysis. the genomic organization of the kahrp gene was determined and the structural basis for the stage specific transcription investigated. a sequence motif with two-fold symmetry was found 160 bp upstream of the rna initiation site. this sequence element inte ... | 1992 | 1620601 |
| [seroprevalence of antibodies against plasmodium falciparum in volunteer donors from various cities in venezuela]. | the prevalence of antibodies to plasmodium falciparum was studied in 890 blood donors from different geographical areas of venezuela. the overall prevalence, as established by elisa, was (1.7%). seropositivity was higher in those samples obtained in sucre (2.5%) and apure (1.7%) states both with foci of malaria transmission. it is proposed that medical history should be reinforced by screening antimalarial antibodies in donors at risk. | 1992 | 1621185 |
| antibody responses stimulated in rabbits, guinea-pigs and mice by recombinant and synthetic portions of a 75 kda malarial merozoite protein. | the 75 kda heat-shock-related protein (p75) of plasmodium falciparum is an abundant, highly conserved, merozoite surface protein. a bacterial clone, c7, produces a polypeptide (c7ag) of approximately 30 kda representing the c-terminal 40% of p75. in several species of animals, the c7ag stimulated high titre igg antibodies which cross-react with p75. two major portions of the c7ag, theoretically predicted to have strong secondary structural preferences, were modelled with four synthetic peptides. ... | 1992 | 1621418 |
| malaria chemoprophylaxis using proguanil/dapsone combinations on the thai-cambodian border. | the thai-cambodian border is a difficult area in which to provide adequate malaria chemoprophylaxis because of multiple drug-resistant plasmodium falciparum. in 1990-1991, thai soldiers were randomly selected to receive proguanil (200 mg/day) combined with dapsone (4 mg or 12.5 mg/day) (n = 184) or pyrimethamine/dapsone (12.5 mg and 100 mg/week) (n = 177). doxycycline (100 mg/day) was given to men with glucose-6-phosphate dehydrogenase deficiency (n = 77). falciparum malaria attack rates were th ... | 1992 | 1621888 |
| immunogenicity and efficacy trials in aotus nancymai monkeys with model compounds representing parts of a 75-kd merozoite surface antigen of plasmodium falciparum. | we tested the ability of a recombinant dna-encoded fragment (c7ag) of a plasmodium falciparum merozoite protein (p75) and of two carrier-free peptide models (28-mer and 76-mer) to stimulate boostable antibody responses in aotus nancymai monkeys. in addition, we evaluated protection against challenge with the uganda palo alto (fup) strain of this parasite. the data indicate that c7ag elicited a strong and boostable igg antibody response in all the monkeys immunized. however, studies with the pept ... | 1992 | 1621894 |
| low frequency of anti-plasmodium falciparum circumsporozoite repeat antibodies and rate of high malaria transmission in endemic areas of rondonia state in northwestern brazil. | in areas studied in the rondonia state of brazil, a high rate of malaria transmission and a low prevalence of anti-(nanp)4 antibodies are reported. the entomologic data are comparable to those observed in some malaria-endemic areas of africa and asia. however, the frequency of individuals with antibodies to the immunodominant epitope of the circumsporozoite protein of plasmodium falciparum recorded in the four localities of rondonia state was very low when compared with the frequencies recorded ... | 1992 | 1621896 |
| expression of recombinant proteins on the surface of the coagulase-negative bacterium staphylococcus xylosus. | an expression system to allow targeting of heterologous proteins to the cell surface of staphylococcus xylosus, a coagulase-negative gram-positive bacterium, is described. the expression of recombinant gene fragments, fused between gene fragments encoding the signal peptide and the cell surface-binding regions of staphylococcal protein a, targets the resulting fusion proteins to the outer bacterial cell surface via the membrane-anchoring region and the highly charged cell wall-spanning region of ... | 1992 | 1624418 |
| prevention of malaria. | malaria is one of the most prevalent infectious diseases worldwide; it is transmitted in over 100 countries, and it is a major cause of serious morbidity and mortality in travelers. clinicians should inform travelers of their risk, teach them the principles of personal protection, and offer individualized chemoprophylaxis regimens. the increasing prevalence of multiple drug-resistant plasmodium falciparum in many parts of the world makes nonpharmacologic methods of malaria prevention important. | 1992 | 1624779 |
| a carboxyl-terminal fragment of plasmodium falciparum gp195 expressed by a recombinant baculovirus induces antibodies that completely inhibit parasite growth. | the major merozoite surface ag (gp195) of plasmodium falciparum has been shown to protect monkeys against parasite infection, and gp195-based synthetic peptides and recombinant polypeptides have been evaluated as potential malaria vaccines. a major problem in developing a gp195-based recombinant vaccine has been the difficulty in obtaining a recombinant polypeptide that is immunologically equivalent to the native protein. in this study, the carboxyl-terminal processing fragment (p42) of gp195 wa ... | 1992 | 1624802 |
| naturally acquired cellular and humoral immune responses to the major merozoite surface antigen (pfmsp1) of plasmodium falciparum are associated with reduced malaria morbidity. | we have investigated the pattern of acquired immune responses to the major surface protein of plasmodium falciparum merozoites (gp 190, pfmsp1) in a malaria endemic population in west africa. a prospective longitudinal study in 3- to 8-year-old children was conducted to examine the relationship between naturally acquired immune responses to pfmsp1 and subsequent susceptibility to malaria infection and clinical disease. a population cross-sectional survey was performed to investigate changes in i ... | 1992 | 1625908 |
| plasmodium falciparum synthesizes o-glycosylated glycoproteins containing o-linked n-acetylglucosamine. | asexual blood forms of the human malaria parasite, plasmodium falciparum, synthesize a major glycosylated 195 kda protein that has been considered for the development of a vaccine. beta-elimination-borohydride reduction of the 195 kda glycoprotein and its 16 kda processed product after metabolic labeling of their carbohydrates, showed the presence of derived, labeled glucosaminitol and alanine. this suggests that the 195 and 16 kda glycoproteins contain distinct o-glycosyl linkages and that n-ac ... | 1992 | 1627179 |
| can, a putative oncogene associated with myeloid leukemogenesis, may be activated by fusion of its 3' half to different genes: characterization of the set gene. | the translocation (6;9)(p23;q34) in acute nonlymphocytic leukemia results in the formation of a highly consistent dek-can fusion gene. translocation breakpoints invariably occur in single introns of dek and can, which were named icb-6 and icb-9, respectively. in a case of acute undifferentiated leukemia, a breakpoint was detected in icb-9 of can, whereas no breakpoint could be detected in dek. genomic and cdna cloning showed that instead of dek, a different gene was fused to can, which was named ... | 1992 | 1630450 |
| guillain-barré syndrome in plasmodium falciparum malaria. | a patient with plasmodium falciparum malaria developed peripheral neuropathy. clinical, cerebro-spinal fluid examination and nerve conduction studies confirmed guillain-barré syndrome, not previously reported in p. falciparum malaria. | 1992 | 1630986 |
| antimalarial pharmacokinetics and treatment regimens. | | 1992 | 1633062 |
| naturally acquired cd8+ cytotoxic t lymphocytes against the plasmodium falciparum circumsporozoite protein. | in rodent malaria model systems, protective immunity induced by immunization with irradiated sporozoites is eliminated by in vivo depletion of cd8+ t cells, and adoptive transfer of ctl clones against the circumsporozoite protein protects against malaria. we recently demonstrated that volunteers immunized with irradiated plasmodium falciparum sporozoites produce ctl against peptide 368-390 of the p. falciparum circumsporozoite protein. to determine whether natural exposure to malaria induced sim ... | 1992 | 1634778 |
| population dynamics of plasmodium falciparum sporogony in laboratory-infected anopheles gambiae. | the population dynamics of cultured plasmodium falciparum parasites was examined during their sporogonic development in anopheles gambiae mosquitoes. estimates of absolute densities were determined for each life stage, and life tables were constructed for each of 38 experimental infections. macrogametocyte and ookinete mortalities contributed equally to the overall mortality. on average, there was a 40-fold decrease in parasite numbers in the transition from the macrogametocyte to the ookinete s ... | 1992 | 1635032 |
| quinine with tetracycline for the treatment of drug-resistant falciparum malaria in thailand. | reports of deteriorating quinine efficacy prompted us to investigate the ability of quinine-tetracycline to clear parasites and fever from patients with multiple drug-resistant plasmodium falciparum infections. past and present treatment results were compared at two study sites along the thai-cambodian border. in northeastern thailand, quinine-tetracycline cleared parasites more quickly in 1990 than in 1987 (mean 3.4 and 4.0 days, respectively; p = 0.006). in southeastern thailand, there were no ... | 1992 | 1636876 |
| emergence of multidrug-resistant plasmodium falciparum in thailand: in vitro tracking. | mefloquine was introduced into thailand in 1985 for the treatment of plasmodium falciparum infection. recently, clinical failure of mefloquine was observed in southeastern thailand, where an epidemic of falciparum malaria occurred. beginning in 1984 and continuing until 1989, in vitro monitoring of p. falciparum isolates from borai, a border district in the southeastern part of the country, showed a progressive decrease in mefloquine sensitivity until 1989; in 1990, the degree and prevalence of ... | 1992 | 1636877 |
| phagocytosis of plasmodium falciparum-infected human red blood cells by human monocytes: involvement of immune and nonimmune determinants and dependence on parasite developmental stage. | the stage-dependent phagocytosis of plasmodium falciparum-infected erythrocytes (irbc) opsonized with nonimmune serum has been investigated. an average of 2.9 red blood cell (rbc) harboring ring-forms (rirbc) and 7.5 rbc infected with trophozoites (tirbc) or schizonts (sirbc) were ingested per monocyte, in comparison with 0.8 noninfected rbc (nrbc) or 5 rbc oxidatively damaged with diamide. abrogation of generation of complement component c3b or blockage of its binding to the phagocyte inhibited ... | 1992 | 1638029 |
| therapy of plasmodium falciparum parasitemia with desferrioxamine. | | 1992 | 1638034 |
| susceptibility of plasmodium falciparum strains to mefloquine in an urban area in senegal. | a total of 47 nonimmune febrile patients from pikine, senegal, with greater than 1,000 plasmodium falciparum asexual forms per microliter whole blood were given 12.5 mg per kg body weight of mefloquine in a single oral dose and were followed up daily until day 7 and also on day 14 of the study. seven of the patients who vomited, four who had 4-aminoquinolines in their blood, and five dropouts were excluded. fever and parasitaemia were suppressed within four days until day fourteen in 29 of the 3 ... | 1992 | 1638665 |
| severe malaria in gambian children is not due to lack of previous exposure to malaria. | the reasons why only a small proportion of african children infected with plasmodium falciparum develop severe or fatal malaria are not known. one possible reason is that children who develop severe disease have had less previous exposure to malaria infection, and hence have less acquired immunity, than children who develop a mild clinical attack. to investigate this possibility we have measured titres of a wide range of anti-p. falciparum antibodies in plasma samples obtained from children with ... | 1992 | 1638773 |
| plasmodium falciparum: identification and purification of the phosphoglycerate kinase of the malaria parasite. | multiplication of the human malaria parasite plasmodium falciparum within red blood cells is an energy-dependent process and glucose consumption increases dramatically in infected red blood cells (irbc) versus normal red blood cells (nrbc). the major pathway for glucose metabolism in p. falciparum irbc is anaerobic glycolysis. phosphoglycerate kinase (pgk) is one of the key enzymes of this pathway as it generates atp. we found that the pgk specific activity in p. falciparum irbc is seven times h ... | 1992 | 1639156 |
| plasmodium falciparum: induction of biologically active antibodies to gp195 is dependent on the choice of adjuvants. | | 1992 | 1639161 |
| codon usage in entamoeba histolytica. | the codon usage of 10 e. histolytica genes comprising 4455 codons was analysed. the codon usage revealed an extremely biased use of synonymous codons with a preference for nnu (44%) and nna (41.4%) codons. codons cgg (arg), agg (arg) and ccg (pro) were absent in the e. histolytica genes examined. the codon usage of e. histolytica resembled that of plasmodium falciparum. | 1992 | 1639575 |
| enhanced gametocyte formation in young erythrocytes by plasmodium falciparum in vitro. | two gametocyte-forming clones, hb-3 and 3d7, were used. concentrates of late stage parasites were mixed with bloods containing different proportions of young erythrocytes, and the parasitemia and proportion of gametocytes determined after 2, 3 or 4 days of culture. significantly more gametocytes were formed in light cells than in heavy cells separated from the same normal blood samples. up to seven times more gametocytes were formed in reticulocyte-rich bloods from patients with sickle cell anem ... | 1992 | 1640389 |
| plasmodium falciparum: isolation of intact and erythrocyte-free trophozoites from sorbitol lysates. | an in vitro culture of plasmodium falciparum (isolate fcup-1/rsa) was arrested in the trophozoite stage with alpha-difluoromethylornithine (dfmo), followed by sorbitol treatment to liberate intracellular parasites from infected erythrocytes. most of the unlysed erythrocytes and ghost membranes were removed by filtration, after agglutination with anti-erythrocyte monoclonal antibodies or wheat-germ agglutinin. a highly purified parasite preparation was obtained after chromatography on an immuno-a ... | 1992 | 1641237 |
| gametocyte sex ratios as indirect measures of outcrossing rates in malaria. | the frequency of recombination between unlike genotypes is central to understanding the generation of genetic diversity in natural populations of malaria. here we suggest a way of investigating the problem which could complement conventional biochemical approaches to the population genetics of malaria. sex allocation theory is one of the most successful areas of evolutionary biology. a well-supported prediction is that progressively less female-biased sex ratios are favoured with more outcrossin ... | 1992 | 1641238 |
| development of the new antimalarial drug pyronaridine: a review. | this report outlines the structure scheme and development of a new antimalarial drug pyronaridine, which was synthesized from either 2-aminopyridine or pyridine. a series of in vivo and in vitro experimental studies and the assessment of toxicity revealed pyronaridine to be a promising agent against erythrocytic stage of malaria parasites. it exhibited low toxicity and had no cross-resistance to chloroquine. clinical administration in malaria cases showed high efficacy and mild side-effects. in ... | 1992 | 1642789 |
| serum cytokine profiles in experimental human malaria. relationship to protection and disease course after challenge. | serum cytokine profiles were evaluated in immunized and nonimmunized human volunteers after challenge with infectious plasmodium falciparum sporozoites. three volunteers had been immunized with x-irradiated sporozoites and were fully protected from infection. four nonimmune volunteers all developed symptomatic infection at which time they were treated. sera from all volunteers were collected at approximately 20 time points during the 28-d challenge period; levels of il-1 alpha, il-1 beta, il-2, ... | 1992 | 1644922 |
| acute renal failure in severe chloroquine resistant falciparum malaria. | we observed 3 patients with a severe falciparum malaria infection. although the patients appeared not to be seriously ill on admission, severe complications occurred. renal impairment was a prominent feature and haemodialysis was sometimes necessary. many hypotheses have been proposed regarding the aetiology of renal failure in plasmodium falciparum but cannot yet be fully substantiated. whatever the aetiology of renal failure might be, we believe that treatment should not differ essentially fro ... | 1992 | 1644968 |
| the effect of free radicals induced by paraquat and copper on the in vitro development of plasmodium falciparum. | the role of transition metals in paraquat toxicity was studied in cultures of plasmodium falciparum. we showed that addition of copper led to an enhancement of the plasmodium killing, whereas addition of chelating agents, such as desferrioxamine and diethylenetriamine pentaacetic acid markedly reduced the toxic effects. parsitized g6pd deficient erythrocytes were more sensitive than parasitized normal erythrocytes to copper and to the combination of copper and paraquat. | 1991 | 1649081 |
| drugs recently released in belgium. mefloquine--ciprofibrate. | | 1991 | 1649529 |
| characterization of the gene encoding the largest subunit of plasmodium falciparum rna polymerase iii. | we report here the isolation, sequence analysis, structure, and expression of the gene encoding the largest subunit of rna polymerase iii (rpiii) from plasmodium falciparum. the p. falciparum rpiii gene consists of 5 exons and 4 introns, is expressed in all of the asexual erythrocytic stages of the parasite as a 8.5-kb mrna, and is present in a single copy on chromosome 13. the predicted 2339 amino acid residue rpiii subunit contained 5 regions that were conserved between different eukaryotic rp ... | 1991 | 1656254 |
| transport of lactate in plasmodium falciparum-infected human erythrocytes. | the intraerythrocytic human malarial parasite plasmodium falciparum produces lactate at a rate that exceeds the maximal capacity of the normal red cell membrane to transport lactate. in order to establish how the infected cell removes this excess lactate, the transport of lactate across the host cell and the parasite membranes has been investigated. transport of radiolabeled l-lactate across the host cell membrane was shown to increase ca. 600-fold compared to uninfected erythrocytes. it showed ... | 1991 | 1660483 |
| [malaria infection during childbirth and in newborns in bécédi (ivory coast)]. | authors studied the parasitological and serological status of 108 new-born children from 102 deliveries during the 2nd term of 1987 at the bécédi maternity hospital in ivory coast. the parasitism frequency of different studied bloods (mother, cord, delivery) is varying from 8 to 14%, antibodies have been found in 81 to 83% cases. the parity has an effect on the placental lesions frequency but not on the parasitism frequency. children born with a pathogenic placenta have a lower birth weight. the ... | 1991 | 1662558 |
| growth inhibition of plasmodium falciparum involving carbon centered iron-chelate radical (l., x-)-fe(iii) based on pyridoxal-betaine. a novel type of antimalarials active against chloroquine-resistant parasites. | malaria parasites have been shown to be more susceptible to oxidative stress than their host erythrocytes. in the present work, a chloroquine resistant malaria parasite, plasmodium falciparum (fcr-3) was found to be susceptible in vitro to a pyridoxal based iron chelator--(1-[n-ethoxycarbonylmethylpyridoxlidenium]-2-[2'-pyridyl ] hydrazine bromide--(code named l2-9). 2h exposure to 20 microm l2-9 was sufficient to irreversibly inhibit parasite growth. desferrioxamine blocked the drug effect, ind ... | 1991 | 1663064 |
| malarial dihydroorotate dehydrogenase mediates superoxide radical production. | dihydroorotate dehydrogenase purified from mitochondria of plasmodium berghei, a rodent malaria parasite, mediates production of superoxide radical during oxidation of dihydroorotate to orotate. reduction of dichlorophenolindophenol or cytochrome c or nitroblue tetrazolium was significantly inhibited by superoxide dismutase or theonyltrifluoroacetone, a specific iron chelator of the enzyme. these results, together with the recent evidence of manganese-superoxide dismutase activity in malarial mi ... | 1991 | 1663740 |
| type ri resistance to halofantrine in west africa. | a case of recrudescent falciparum malaria after halofantrine treatment is described. the patient contracted plasmodium falciparum in ivory coast and was treated with halofantrine. plasma levels of halofantrine and its metabolite were adequate. thirty-one days after treatment, the patient was rehospitalized with symptoms of malaria. recrudescence was confirmed by microscopic examination, indicating a type ri resistance to halofantrine. mefloquine was given to treat recrudescent malaria. the paras ... | 1991 | 1665577 |
| calcium transport and compartment analysis of free and exchangeable calcium in plasmodium falciparum-infected red blood cells. | calcium (ca2+) is indispensable for normal development of the various stages of the asexual erythrocytic cycle of malaria parasites. however, the mechanisms involved in ca2+ uptake, compartmentalization and cellular regulation are poorly understood. to clarify some of these issues, we have measured total, exchangeable, and free ca2+ in normal red cells (rbcs) and plasmodium falciparum (fcr-3)-infected cells (irbcs) as a function of parasite development. all three forms of ca2+ were found to be s ... | 1991 | 1667934 |
| cross-reactions between idiotypes, plasmodium falciparum derived peptides, dinitrophenyl and beta(2-->6) polyfructosan. | in this paper we seek evidence for the participation of the idiotype-anti-idiotype network in the polyclonal b-cell activation (pba) associated to malaria. for this purpose we tested by an immunoradiometric assay a panel of nine monoclonal antibodies (including seven anti-idiotype antibodies) against three different (plasmodial or non plasmodial) heteroantigens: the 307 synthetic peptide (an epitope of a p. falciparum hepatic stage specific antigen) the (nanp)4 synthetic peptide (a repetitive ep ... | 1991 | 1668857 |
| malaria and widal reaction. | widal reaction was studied in 52 patients having malaria parasites in the peripheral blood smear. twenty had plasmodium vivax, 26 had plasmodium falciparum and the rest had mixed (both vivax and falciparum) infections. widal test for both o and h antigens of salmonella typhi was positive in high titres in 3 falciparum, 3 vivax and 2 cases of mixed infection. of these 8 cases, one had been treated for typhoid fever 3 months back and again one month back for relapse. blood culture for salmonella t ... | 1991 | 1669964 |
| cerebral malaria. | | 1991 | 1670700 |
| rapid diagnosis of malaria by fluorescence microscopy with light microscope and interference filter. | fluorochrome staining to detect malaria parasites in bloodfilms is more sensitive, is easier to do, and is less time-consuming than giemsa staining. however, standard epi-illuminated, mercury vapour, fluorescence microscopes are expensive, especially for tropical countries where malaria is endemic. fluorescence microscopy with a standard light microscope and a new interference filter specially designed for the fluorochrome stain, acridine orange, was used to detect malaria parasites in thick and ... | 1991 | 1670842 |
| simplified preparation of malarial blood samples for polymerase chain reaction. | | 1991 | 1671140 |
| treating cerebral malaria. | | 1991 | 1671457 |
| changes in the peripheral blood eosinophil count in falciparum malaria. | | 1991 | 1671625 |