Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glycophorin both in solution and inserted into liposomes blocks invasion of erythrocytes by the malaria parasite Plasmodium falciparum. Furthermore, one sugar, N-acetyl-D-glucosamine (GlcNAc), completely blocks invasion of the erythrocyte by this parasite. GlcNAc coupled to bovine serum albumin to prevent the sugar entering infected erythrocytes was at least 100,000 times more effective than GlcNAc alone. Bovine serum albumin coupled to lactose or bovine serum albumin alone had no effect on invasion. These results suggest that the binding of P. falciparum to erythrocytes is lectin-like and is determined by carbohydrates on glycophorin.
 ...
PMID:A lectin-like receptor is involved in invasion of erythrocytes by Plasmodium falciparum. 634 86

Continuous in vitro cultivation of the malaria parasite, Plasmodium falciparum, was performed in plasma-free medium. The medium used was standard RPMI 1640 supplemented with adenosine, unsaturated C-18 fatty acids, and fatty acid-free bovine serum albumin. The medium was changed daily and the cultures were diluted with washed erythrocytes twice weekly. Growth was routinely maintained for 1 month at which time the experiments were usually terminated. Although the overall growth rates were consistently lower than in control cultures with plasma, continuous growth occurred in the absence of plasma in cultures containing cis-vaccenic, oleic, and linoleic acids.
 ...
PMID:Plasmodium falciparum: continuous cultivation of erythrocyte stages in plasma-free culture medium. 636 17

Immunosuppression in malaria has been attributed, in part, to alterations in macrophage function. The present study was undertaken in an attempt to characterize the dysfunction and to determine if it is regional or if it occurs in different populations of macrophages. The resting O2 consumption of either hepatic, splenic, or peritoneal macrophages or polymorphonuclear neutrophils (PMNs) was unaltered by the malaria infection. However, the respiratory burst was significantly enhanced in the three macrophage populations but not in the PMNs. A significant increase in their phagocytic capacity and microbicidal activity was noted for hepatic and peritoneal but not splenic macrophages or PMNs. The malaria-infected mice had a marked decrease in serum antibody and splenic plaque response to bovine serum albumin (BSA) but not to keyhole limpet hemocyanin (KLH). Following an in vitro incubation with BSA, splenic macrophages from infected mice were not able to induce an antibody response when injected into normal mice. However, following incubation with KLH splenic macrophages could induce an adequate response in normal mice. This ability of macrophages from malaria-infected mice to transfer (or induce) a response in normal mice appeared to correlate with the amount of antigen digested, or perhaps retained, by the cells, i.e., BSA digestion was significantly less than KLH. These results indicate that the macrophage dysfunction in malaria is distinct depending on the tissue population that the macrophage is obtained from and that the impaired antibody response may be restricted to antigens requiring macrophage processing.
 ...
PMID:Characterization of macrophage dysfunction in rodent malaria. 638 42

A micro enzyme-linked immunosorbent assay utilizing antigen dotted onto nitrocellulose filter discs (Dot-ELISA) was developed for the rapid diagnosis of visceral leishmaniasis. Leishmania donovani promastigotes applied to filter discs in volumes of 1 microliter were placed in 96-well microtiter plates, blocked with bovine serum albumin, then incubated with 4-fold dilutions of patient sera. After incubation with peroxidase-conjugated anti-human antibody, washing and addition of precipitable substrate, positive reactions appeared as blue dots on a white background which were easily read by eye. The procedure is performed at room temperature, takes about 2 h and is economical. At a reciprocal diagnostic titer of greater than or equal to 32, 41 of 42 (98%) leishmaniasis patients were positive, and positive titers ranged from 512 to 524,288. Control sera from healthy individuals showed 1 of 50 (2%) false positive reactions. Sera from patients with African trypanosomiasis, Chagas' disease, and lupus erythematosus were cross-reactive in the Dot-ELISA. No cross-reactivity was noted with sera from patients with amebiasis, coccidioidomycosis, cutaneous leishmaniasis, viral hepatitis, hydatidosis, malaria, schistosomiasis, syphilis, toxoplasmosis or trichinosis. In replicate experiments, 90% of 167 sera tested did not vary in titer. This rapid and inexpensive test should prove to be an important field diagnostic technique for visceral leishmaniasis.
 ...
PMID:Dot enzyme-linked immunosorbent assay (Dot-ELISA): a micro technique for the rapid diagnosis of visceral leishmaniasis. 654 6

Bovine serum albumin and preparations of cell sap from malaria parasites and normal erythrocytes were tested for ability to protect cellular membranes against the toxicity of ferriprotoporphyrin IX (FP) and a chloroquine-FP complex. Suspensions of Plasmodium berghei (approximately 7 X 10(6) parasites per ml, isolated from saponin-lysed, infected erythrocytes) were used as a test system. Toxicity was monitored by measuring changes in turbidity of these suspensions at 700 nm. Parasite cell sap (0.56 mg protein per ml) and albumin (1 mg per ml) completely prevented the toxicity of 40 micrometers FP. Erythrocyte cell sap (8.6 mg of hemoglobin per ml). Provided only partial protection from 40 micrometers FP. Neither the cell sap preparations nor albumin eliminated the toxicity of a chloroquine-FP complex formed from 20 micrometers chloroquine and 40 micrometers FP. These observations suggest that the cell sap preparations contain FP binding substances and that the mode of action of chloroquine may be to shunt FP away from a nontoxic complex with these substances and into a toxic chloroquine-FP complex.
 ...
PMID:Ferriprotoporphyrin IX binding substances and the mode of action of chloroquine against malaria. 675 19

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

Serum cholinesterase activities were determined in 87 patients of both sexes with P. falciparum malaria in comparison to those of 80 blood donors. Patients with acute P. falciparum malaria had significantly lower serum cholinesterase activity than those of the control group. After treatment, their serum cholinesterase levels returned to the normal level. Serum albumin concentration also showed the same pattern and had a direct relationship to those of serum cholinesterase levels. These findings indicated that malarial parasites had some effect on the liver cells which resulted in impaired hepatic synthesis of serum cholinesterase and albumin concentrations. This result therefore add new information that there was a disturbance of enzyme cholinesterase among many liver enzymes that have been shown to be altered during an acute malarial attack.
 ...
PMID:Serum cholinesterase activity in patients with malaria infection. 701 93

Free fatty acids (FFA) in blood are carried by serum albumin. A hypothesis is offered that conditions giving a high molar ratio of FFA to albumin may lead to dysfunction of the cells which are directly exposed to the high FFA/albumin ratio, i.e. the red and white blood cells, and endothelial cells. The hypothesis is supported by observations of (1) hemolytic effect of FFA, and protection by albumin in vitro, (2) inhibition of white blood cells by FFA, (3) increased FFA/albumin ratio and erythrocyte susceptibility to hemolysis in pre-eclampsia, (4) increased incidence of eclampsia in undernutrition, (5) the paradox at famine suppresses and refeeding activates malaria, and (6) an inverse relationship between serum albumin level and mortality.
 ...
PMID:Serum fatty acid/albumin molar ratio and the risk of diseases. 747 3

A cell-ELISA was developed using monolayers of glutaraldehyde-fixed normal as well as Plasmodium berghei-infected mouse erythrocytes for quantification and characterization of anti-erythrocytic autoantibodies in murine malaria. Testing normal (NMS) and peak parasitaemic sera (PPS) on erythrocyte monolayers treated with trypsin, sodium meta periodate, neuraminidase or heat, and competitive inhibition of antibodies with soluble sialic acid, revealed that some anti-erythrocytic antibodies (which increase during the parasitaemic phase of infection) recognize N-acetyl neuraminic acid (NANA) residues on host erythrocytes. High levels of antibodies to NANA covalently conjugated to bovine serum albumin (BSA) were detectable in PPS. Such antibodies could be significantly absorbed out by preincubation of PPS with mouse erythrocytes (MRBC). Antibodies in PPS, when affinity-purified on a column of Fetuin-Agarose, were found to be reactive to normal as well as parasitized erythrocyte monolayers. Immunoglobulin isotyping and IgG subgroup typing revealed that most of the anti-erythrocytic autoantibodies in NMS were IgM and IgA, while in PPS there was an appreciable increase in IgG2a and IgG3. Affinity-purified anti-NANA antibodies reacted with DNA when tested in an ELISA. There was a significant positive correlation between anti-erythrocytic antibody and DNA-binding levels in NMS as well as PPS. The DNA-binding antibodies in PPS could be effectively absorbed out by preincubation of sera with fresh MRBC. Affinity determination of anti-erythrocytic antibodies eluted from MRBC revealed binding characteristics in the following order: MRBC > single-stranded DNA > double-stranded DNA.
 ...
PMID:Murine malaria: anti-erythrocytic antibodies recognize N-acetyl neuraminic acid residues. 750 18

The primary immune response to T cell-dependent Ags develops in two pathways. These comprise the extrafollicular pathway, in which foci of Ab-secreting cells develop, and the intrafollicular pathway that gives rise to germinal centers and affinity maturation. We have previously shown that de-aggregated (4-hydroxy-3-nitrophenyl) acetyl (NP) coupled to the protein carrier human serum albumin (HSA), (NP-HSA), injected 6 days after challenge immunization with aggregated NP-HSA, resulted in impaired development of NP-specific, higher-affinity cells. Studies presented here describe the cellular basis underlying this impairment of affinity maturation. Using multiparameter flow cytometry, we show that mice injected with soluble NP-HSA ("tolerant" mice) develop significantly fewer NP-binding IgG1+ B220+ cells of germinal center origin than do the control ("immune") mice. In addition, using immunohistology, we noted that the spleens of tolerant mice had a marked reduction in the number of germinal centers that contained lambda-bearing cells, these being characteristic of the NP response in C57BL/6 mice. Curiously, germinal centers in the spleens of tolerant mice had more than twice the volumes of those in the immune spleens. In contrast to its effect on the germinal center pathway, soluble Ag enhanced the extrafollicular pathway, reflected by the increased numbers of B cells secreting IgM and IgG1 Abs specific for NP, HSA, and undefined Ags. Thus, soluble NP-HSA given after challenge immunization can impede affinity maturation of NP-specific cells, but enhance the extrafollicular pathway. These results are discussed in the context of the known capacity of some persisting Ags, e.g., malaria parasites, to frustrate affinity maturation and memory cell generation.
 ...
PMID:Soluble antigen can impede affinity maturation and the germinal center reaction but enhance extrafollicular immunoglobulin production. 754 16


<< Previous 1 2 3 4 5 6 7 8 Next >>