While the effect of reactive nitrogen intermediates (RNI) against macrophage-dwelling protozoa, such as Leishmania and Toxoplasma has become established, the possible antiparasitic function of nitric oxide (NO) and RNI against the intracellular blood stages of malaria and babesia has, until recently, been less well accepted. This was, at least in ...

In an attempt to see if the OptiMAL dipstick (Flow Inc., Portland, OR) can be used to monitor antimalarial treatment, a pilot study of 17 patients with Plasmodium falciparum malaria, admitted to the Hospital for Tropical Diseases in London, U.K., was conducted. Sequential, follow-up, blood specimens were obtained from day ...

The multiplication rates and invasiveness of Plasmodium falciparum parasites isolated from adult Thai patients hospitalized with uncomplicated malaria (n=34) were compared with those from persons with severe malaria (n=42). To simulate severe malaria and control for host effects, the in vitro cultures were adjusted to 1% parasitemia and used the ...

Microglial activation and redistribution toward blood vessels are some of the earliest observable events occurring within the central nervous system (CNS) during fatal murine cerebral malaria (FMCM). To investigate stimuli that might modulate microglial reactivity during FMCM we have performed two experimental manipulations and observed microglial responses in retinal whole ...

A procedure for optimizing the configuration of flow cytometers for enumerating micronucleated erythrocytes is described. The method is based on the use of a biological model for micronucleated erythrocytes, the malaria parasite Plasmodium berghei. P. berghei endows target cells of interest (erythrocytes) with a micronucleus-like DNA content. Unlike micronuclei, parasitized ...

An evaluation of 3 different methods for malaria diagnosis was carried out in an urban area of low endemicity on the Pacific coast of Colombia. Samples were collected from 833 symptomatic patients at a malaria clinic and examined by the polymerase chain reaction (PCR), quantitative buffy coat (QBC; Becton Dickinson, ...

To test the diagnostic value of a rapid and simple immunochromatographic test (ICT) based on the detection of Plasmodium falciparum histidine-rich protein 2 (PfHRP2) for post-mortem examination, blood samples from 30 consecutive corpses were analysed by ICT and Giemsa-stained blood films. Compared to microscopy, ICT had 100% sensitivity and 100% ...

Morphological characteristics and functions of hemocytes were used to compare the immunological effects of biological and chemical stress in the freshwater snail Lymnaea palustris. Animals were either infected by a trematode parasite (Metaleptocephalus sp.), or exposed to environmental contaminants, namely atrazine and hexachlorobenzene (HCB). Three populations of circulating hemocytes, morphologically ...

OBJECTIVE: To assess laboratory practice in the examination of blood films for malarial parasites. METHOD: Ontario medical laboratories, licensed by the Ministry of Health, are required to participate in external quality assessment by the Laboratory Proficiency Testing Program, which assesses performance of laboratory assays and also examines the total testing ...

Artemether-lumefantrine is a new fixed antimalarial combination effective against multidrug-resistant falciparum malaria. A prospective electrocardiographic study was conducted in 150 patients receiving artemetherlumefantrine and 50 treated with artesunate-mefloquine. There was no evidence for clinically significant changes in the electrocardiographic intervals and in particular no relationship between plasma concentrations of lumefantrine ...

Infections with certain species of Plasmodium and Babesia induce, among other symptoms, cerebral pathology. The finding of heavily parasitized cerebral capillaries upon postmortem examination has led to the assumption that blockage of capillaries with infected red blood cells caused the cerebral symptoms and subsequent death. As this type of cerebrovascular ...

Four-week-old OF1 mice, infected with synchronized Plasmodium chabaudi chabaudi blood forms, were intraperitoneally injected with the naphthylisoquinoline alkaloid dioncophylline B (10 mg kg(-1) day(-1)) at three consecutive days. The respective groups were treated when rings, trophozoites, and schizonts were predominant. Microscopical observations of thin blood smears were made every two ...

After the description in Grand Canary Island of a case of dromedary trypanosomosis caused by Trypanosoma evansi in 1998, an indirect enzyme immunoassay for the detection of specific anti-T. evansi IgG (Ab-ELISA) was used to assess the seroprevalence of this disease on the Canary Islands. Seroprevalence was 9.0% in the ...

Blood erythrocytes of 25 confirrhed malarial patients infested with P. vivax were analyzed for peroxidation and hemolysis and results compared with 10 uninfected normal control samples. Results indicated significant increase in peroxide formation measured as malondialdehyde, both in presence and absence of H2O2, in parasite infested erythrocytes. These changes induced ...

Toxoplasmosis is a worldwide disease caused by Toxoplasma gondii, an intracellular protozoa of micronic size range (4-10 microm). Its classical purification processes are complex and often associated with low recovery. All investigation procedures concerning this parasite require its isolation and purification from at least the mouse ascitic fluid. For this ...

Between 1989 and 1995, blood surveys were performed for Wuchereria bancrofti infection in several barracks of the Brazilian army in the metropolitan Recife region. For initial screening, 60 microliters of capillary blood were examined for microfilaria. All men who tested positive had microfilaria quantified by filtration of venous blood through ...

Biological samples were collected from dogs in resource-limited communities in the North-West and Gauteng Provinces of South Africa to assess the prevalence of helminth parasitism. These samples included adhesive tape peri-anal skin swabs and fresh faecal samples for helminth examination, and thick and thin blood films (smears) and whole-blood samples ...

We report an exceptional finding from a blood slide collected in a remote area in the western half of New Guinea Island (Irian Jaya Province, Indonesia). One adolescent patient was found patently coinfected with all 4 known human malaria species, Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, and Plasmodium ovale. Diagnostic ...

Decreased erythropoiesis and increased clearance of both parasitized and noninfected erythrocytes both contribute to the pathogenesis of anemia in falciparum malaria. Erythrocytes with reduced deformability are more likely to be cleared from the circulation by the spleen, a process that is augmented in acute malaria. Using a laser diffraction technique, ...

Certain red blood cell (RBC) disorders, including thalassemia, have been associated with an innate protection against malaria infection. However, many in vitro correlative studies have been inconclusive. To better understand the relationship between human RBCs with thalassemia hemoglobinopathies and susceptibility to in vitro infection, we used an in vitro coculture ...

Chlorpheniramine (CP), a histamine H1-receptor antagonist, enhances the efficacy of chloroquine (CQ) in acute uncomplicated falciparum malaria. The effects of this combination therapy on the pharmacokinetic disposition of CQ is, however, unpredictable. A standard treatment with 25 mg CQ base per kg bodyweight was orally administered over 3 days, alone ...

A nested polymerase chain reaction (PCR) assay that uses Plasmodium genus-specific primers for the initial PCR (nest 1) amplification and either genus- or species-specific primers for the nest 2 amplifications was tested on laboratory and field samples. With in vitro cultured Plasmodium falciparum-infected blood samples, it was capable of detecting ...

The age old Romanowsky stained thick blood smear examination for malarial parasites may fail to reveal the low parasitaemia. The commercial 'QBC' like acridine orange stained capillary tube preparation has a limitation of precise species identification and the detection of extra-erythrocytic parasites. Hence, the present study was aimed to improve ...

In regions highly endemic for Plasmodium falciparum malaria, red cell polymorphisms that confer resistance to severe disease are widespread. Sickle cell trait, alpha-thalassemia, glucose-6-phosphate dehydrogenase deficiency, and blood groups were determined in 100 children from Gabon with severe malaria who were matched with 100 children with mild malaria and followed ...

OBJECTIVES: This study was undertaken to determine the relative effect of malaria infection on HIV concentration in blood plasma, and prospectively to monitor viral concentrations after antimalarial therapy. DESIGN: A prospective, double cohort study was designed to compare the blood HIV-1 RNA concentrations of HIV-positive individuals with and without acute ...

Quantitative buffy coats (QBC) technique was compared with conventional blood film technique for the diagnosis of malaria in a tertiary care hospital. The QBC technique was found to be a rapid technique with a sensitivity of 83% and specificity of 94%. Malaria species identification was also possible. It was essentially ...

OBJECTIVE: Among the mechanisms suggested for altered consciousness during cerebral malaria is the hypothesis of cerebral ischemia, which remains controversial, with little supportive O2 conflicting hemodynamic data. The purpose of this study was to test the hypothesis that cerebral ischemia is a main mechanism for altered consciousness during cerebral malaria. ...

We studied female choice and reproductive success in a marked population of sedge warblers Acrocephalus schoenobaenus, from 1995 to 1996. Three genera of parasitic blood protozoans, namely Haemoproteus sp. Trypanosoma sp. Plasmodium sp., were identified from blood samples taken from all breeding adults. Relatively high prevalence values of 19.5% in ...

OBJECTIVE: Although fecal occult blood (FOB) tests have most often been used to detect occult bleeding from the lower gastrointestinal (GI) tract, their utility in detecting occult blood loss from the upper GI tract is less well understood. The aims of this study were to determine whether small amounts of ...

Concentrates of late stage parasites of the gametocyte-forming clone HB-3 were mixed with blood rich in reticulocytes from anemic patients, or with normal control blood, and kept under culture conditions for 4 days. Significantly more gametocytes were always formed in the reticulocyte-rich blood than in the control. This was true ...

The susceptibilities to coindigenous Plasmodium vivax of colonized Anopheles albimanus and Anopheles pseudopunctipennis from southern Mexico were investigated by simultaneous feeding with infected blood obtained from patients. The genes encoding circumsporozoite protein variant types (VK210 and VK247) in blood samples were determined by PCR and oligonucleotide probe hybridization. A. albimanus ...

Three methods for the quantitation of parasitaemia in malaria were compared with the standard method for ascertaining the accuracy in patients, Plasmodium berghei infected mice and P. knowlesi infected Rhesus monkeys. Technique I, where parasitaemia was calculated from the number of PRBCs in 10,000 RBCs in thin blood film and ...

We report in this work a highly sensitive and nonradioactive PCR method for the detection of the four species of parasite causing human malaria. Plasmodium-specific primers corresponding to the small-subunit rRNA genes of the malaria parasite were used, and a 291-bp fragment was amplified. Our results showed a high specificity ...

The available antimalarial drugs for the treatment of Plasmodium falciparum malaria during pregnancy are potentially toxic, especially in the presence of red blood cells (RBC) defects. We describe a case of chloroquine-resistant malaria by P. falciparum in a pregnant woman with glucose-6-phosphate dehydrogenase (G6PD) deficiency successfully treated with pyrimethamine followed ...

We studied 424 adults with falciparum malaria admitted over 28 months. They were divided into three groups: cerebral malaria (n = 214); severe non-cerebral malaria (n = 58); and uncomplicated malaria (n = 152). Fundus examination was done daily from admission to discharge, and weekly thereafter in those with persistent ...

Five species of lizards, Agama yemenensis, A. adramitana, Chamaeleo chamaeleon, C. calyptratus and Acanthodactylus baskinaus were trapped alive from Abha Province. Serological and parasitological examinations of blood revealed antibodies against toxoplasmosis and leishmaniasis. Blood films showed Hepatozoon spp. The results were discussed with reference to their role as reservoir hosts.

The role of endogenous and internalized catalase in the protection of Plasmodium against oxidant stress was studied. Catalase activities were measured in isolated Plasmodium falciparum at different stages of intererythrocytic development. Activities measured at late schizont stages were compared to parasite markers (glutamate dehydrogenase, SOD) and to red blood cell ...

Red cell oval morphology is still the only accepted basis for the clinical or epidemiological diagnosis of ovalocytosis. Therefore it is important to know the errors when detecting and counting morphological ovalocytes. In all previous studies of ovalocytosis there was no assessment of the variation which may have occurred in ...

We report an adaptation of a technique for the blood sample collection (GFM) as well as for the extraction and amplification of Plasmodium DNA for the diagnosis of malaria infection by the PCR/ELISA. The method of blood sample collection requires less expertise and saves both time and money, thus reducing ...

Current models of immunity to blood stages of Plasmodium invoke a primary role for T-cell dependent processes and much recent evidence implicates Th1-type responses as crucial to the control of acute malaria. But do these data stand up to close scrutiny? Here, Andy Fell and Nick Smith review recent data ...

To investigate the rosette formation properties of Plasmodium vivax, blood was sampled from 26 adult Thai patients admitted with acute P. vivax malaria and a predominance of trophozoite and schizont stages in their peripheral blood smears. In each case, P. vivax-infected cells formed spontaneous rosettes with two or more uninfected ...

Colonic diverticula have been generally accepted as a source of massive hemorrhaging. Little is known, however, about fecal occult blood loss from colonic diverticula and diverticulosis. We retrospectively investigated the possibility of minor bleeding in 737 diverticula cases diagnosed from April 1989 to May 1994. Thirty-seven cases (5%) of diverticula ...

The effectiveness of mefloquine to prevent malaria caused by Plasmodium falciparum is influenced by the sensitivity of the malaria parasites to this drug. Concern has been raised that resistance to mefloquine may develop in sub-Saharan Africa as has been observed in Southeast Asia. Case reports, along with blood smears to ...

Transmission of a Babesia species to susceptible cattle by Rhipicephalus evertsi evertsi ticks picked off a sable which died of acute babesiosis is described. The parasite was initially isolated by feeding R. e. evertsi ticks on a susceptible, splenectomised bovine which developed parasitaemia. Blood stabilate from the parasitaemic bovine produced ...

To assess the possibility of developing a protocol for the clinical diagnosis of malaria, a study was done at the regional laboratory of the Anti-Malaria Campaign in Puttalam, Sri Lanka. Of a group of 502 patients, who suspected they were suffering from malaria, 97 had a positive blood film for ...

Life-threatening fungal infections have increased significantly in the past decade due to the rising number of immunocompromised patients. Serological diagnosis of most fungal infections is unreliable and blood cultures are positive in only 50% of premortem cases; therefore, tissue sampling together with fast, reliable staining of fungi should be carried ...

Transmission of Plasmodium falciparum can be reduced by immune factors present in the mosquito blood meal. Specific antibodies and white blood cells (WBCs) can interact with the sexual stages of the parasite inside the mosquito midgut. The relative contribution of serum factors and WBCs on transmission reduction in gametocyte carriers ...

Single-rooted premolar teeth, stained with blood utilizing the technique devised by Freccia & Peters (1981), were subjected to traditional and non-peroxide bleaching agents. Colour changes were recorded over a period of 7 days using a Speedmaster R75-CP Reflection Densitometer. The most efficient removal of staining occurred after the application of ...

A study to investigate the association between blood glutathione (GSH) levels and biliary excretory status was conducted in apparently healthy Ghanaian subjects without frank biliary disease and anaemia. The results showed that, in adults (mean age: 38.5 years) and children (mean age: 13.0 years), plasma conjugated bilirubin is inversely correlated ...

Free-ranging Old World primates released on St. Catherine's Island, Georgia (USA), were tested for infection with Trypanosoma cruzi as part of a study of the epizootiology of sylvatic T. cruzi in the southeastern USA. The parasite was observed in liver infusion tryptose medium cultures of blood from seven of 11 ...