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)

Tumor necrosis factor and related cytokines are thought to be implicated in cell-mediated immunity and pathophysiology in malaria, but their mechanism of action has not been ascertained. Tumor necrosis factor has been reported to generate nitric oxide in vitro, so we have measured levels of this molecule and its products in the plasma of mice after they have received an injection of tumor necrosis factor, lymphotoxin, interleukin-1, gamma interferon, or interleukin-6, all of which have been reported to be increased in malaria. Total reactive nitrogen intermediate levels in plasma were assayed spectrophotometrically after exposing plasma to a copper-cadmium-zinc catalyst to convert nitrate to nitrite and then to Griess reagent. Tumor necrosis factor, lymphotoxin, and interleukin-1 all induced reactive nitrogen intermediates in vivo, with interleukin-1 showing the most activity. Tumor necrosis factor was then examined more closely. It induced more reactive nitrogen intermediates in malaria-infected mice than in normal mice, and appreciably more was in the form of nitrate than was in the form of nitrite. NG-methyl-L-arginine inhibited the in vivo generation of reactive nitrogen intermediates by tumor necrosis factor in a dose-dependent manner, implying that these molecules were arginine derived. These results are consistent with the possibility that tumor necrosis factor, lymphotoxin, and interleukin-1 may contribute to host pathology and parasite suppression through generation of nitric oxide.
 ...
PMID:In vivo induction of nitrite and nitrate by tumor necrosis factor, lymphotoxin, and interleukin-1: possible roles in malaria. 150 Jan 82

In a cross-sectional study of 123 children aged 24-120 mo from the Wosera subdistrict of Papua New Guinea, height, weight, hematocrit, hemoglobin, hair zinc, and presence of malaria were measured. Two 24-h recalls were undertaken in 67 of the children aged 72-120 mo; 52%, 73%, and 76% had energy, protein, and zinc intakes, respectively, less than two-thirds of the FAO/WHO/UNU recommendations. Stunting was prevalent (29%); 16% were moderately wasted. The prevalence of stunting and hair zinc concentrations less than 1.68 mumol/g was gender related; 38% of males vs 20% of females had Z scores for height-for-age (HAZ scores) less than -2 (P = 0.04); 26% of males vs 11% of females had hair zinc less than 1.68 mumol/g (P less than 0.05). Analysis of variance showed that age, sex, hemoglobin, and log hair zinc influenced HAZ scores, depending on the age group; both sex and the log of the hair zinc values were significant factors in the older children. Stunting in Worsera children was related to chronic deficits in energy and protein and was excerbated in the older male children by suboptimal zinc status.
 ...
PMID:Growth in children from the Wosera subdistrict, Papua New Guinea, in relation to energy and protein intakes and zinc status. 184 37

From 1982 to 1984 170 children of Kikwawila village (Kilombero district, Tanzania) were followed for nutritional (anthropometric measures, hematocrit, serum retinol, prealbumin, and zinc concentrations), parasitological (malaria parasitemia, urinary schistosomiasis, intestinal parasites) and immunological characteristics. Between 2.9% and 12.4% had serum retinol levels less than 100 micrograms/l which indicate deficiency. Retinol concentrations were correlated with age, hematocrits, prealbumin levels and mid upperarm circumferences. The latter correlation may be useful in nutritional surveys and primary health care programs for the identification of populations at risk of retinol deficiency. No association was found between average retinol levels and the presence of parasites, with the exception of malaria. Retinol levels were inversely correlated with malaria parasitemia in 1982, and directly correlated with antibody titers to synthetic sporozoite peptide in 1984. Since retinol, malaria parasitemia, and antisporozoite antibodies increased with age, confounding by age could not be excluded. Six months after administration of ornidazole in a single oral dose of 10 mg/kg, a significant effect on the prevalence of Giardia lamblia was found. Following treatment, average retinol levels were increased in persons with confirmed G. lamblia infections, but not in uninfected or untreated controls.
 ...
PMID:A longitudinal study on relations of retinol with parasitic infections and the immune response in children of Kikwawila village, Tanzania. 289 Dec 70

The asexual stages of Plasmodium living within the erythrocyte result in growth-related changes in the permeability properties of the red cell for substances such as glucose, amino acids, purine nucleosides, sodium, potassium, calcium, zinc, iron and several antimalarial drugs such as chloroquine, amodiaquine and mefloquine. In most cases such changes do not appear to be due to a modification in the affinity or specificity of red cell transporters; indeed, for most substances the membrane-associated transporters are either unaffected or are partially inactivated. In malaria-infected erythrocytes, where a striking increase in influx has been observed, it has been attributed to the insertion of parasite-encoded transporters into the red cell membrane or the formation of aqueous leaks and/or pores. Leak formation, in the vast majority of cases, does not appear to be dependent on the insertion of plasmodial proteins into the red cell membrane. However, since the data presently available are less than satisfactory for discriminating amongst the various possible transport mechanisms future studies will require painstaking efforts and carefully controlled conditions to discriminate amongst the various transport systems which are operational in the malaria-infected red cell and the parasite.
 ...
PMID:The Wellcome Trust lecture. Mechanisms of molecular trafficking in malaria. 328 92

With the osmium tetroxide-zinc iodide impregnation technique the visualization of the internal organization of the exoerythrocytic form of the rodent malaria parasite Plasmodium berghei was improved. Osmium impregnation leached the ground matrix of the parasite thereby displaying a system of intermediate-sized filaments. Because microtubules are only present as part of the mitotic spindle and as remnants of the sporozoite cytoskeleton, the observed intermediate-sized filaments comprise most of the cytoskeletal organization of the liver stage malaria parasite.
 ...
PMID:Organization of the exoerythrocytic stage of the rodent malaria parasite Plasmodium berghei. A cytochemical study. 353 27

One of the major factors in the development of severe protein-energy malnutrition (PEM) is infection, such as diarrhea, upper respiratory infection, and malaria. Social and environmental factors include family size, access to land and occupation of parents, and exposure of rural populations to urban centers. Breast milk has been shown to play a role in the prevention of infections; however, the mother must be well-nourished to provide the optimum product. Traditional foods available to rural children in most developing countries are difficult to digest and low in energy and protein and inadequate nutritional education prevents the inclusion of good protein sources in children's diets. Severe PEM, called marasmus and kwashiorkor is indicated by wasting of muscles, absence of subcutaneous fat, wrinkled skin, thin and sparse hair, and weakness. The basic treatment for severe PEM is dietary. Treatment of kwashiorkor and marasmus is divided into 3 stages: 1) attending to acute problems, 2) restoring nutritional balance, and 3) ensuring nutritional rehabilitation. Care must be taken to ensure a minimum daily intake of 3-4 gm of protein and 120-150 Kcal of energy/kg of body weight. There must be, in addition, replacement of vitamin A, zinc, potassium, magnesium, and iron. An initial regimen which has been advocated is based on dry skim milk, sugar, and vegetable oil, divided into 6-12 feedings/day, which prevents vomiting. It is not necessary to remove lactose from the diet, and other animal protein sources such as meat and meat extracts are also well accepted. Soy and vegetable protein have been used successfully. In treating mild and moderate PEM it is important to ensure the intake of these food supplements by the child and to avoid a major substitution effect in the household diet. It is crucial for the physicians, nutritionists, public health workers, and educators to convince parents about the safety of using foods that are fed only to adults and older children. In addition nutritional and health education must not be restricted to the rehabilitation of the child but the prevention of nutritonal deterioration of the entire family and sometimes to the entire community.
 ...
PMID:Infantile malnutrition in the tropics. 681 12

The zinc-desferrioxamine (Zn-DFO) complex is considered to be more permeative into parasitized erythrocytes than is the metal-free DFO. The former may penetrate the cell and exchange its bound zinc for ferric ions, rendering the iron unavailable for vital parasite functions. The effects of these compounds on the in vitro development of Plasmodium falciparum are compared. The results indicate that Zn-DFO is superior to DFO, especially at concentrations below 20 microM, as shown by decreased levels of hypoxanthine incorporation, lower levels of parasitemia, and interference with the life cycle of the parasite. At low concentrations, DFO even enhanced parasite growth. Such an enhancement was not observed following exposure to Zn-DFO. Experiments in which the compounds were removed from the cultures indicated that parasites treated with Zn-DFO are less likely to recover at a later stage. Since DFO has already been used in humans for the treatment of malaria, its complex with zinc, which is more effective in vitro, should also be examined in vivo.
 ...
PMID:Effects of zinc-desferrioxamine on Plasmodium falciparum in culture. 748 46

In the course of an investigation of hexosamine catabolism in the human malaria parasite, Plasmodium falciparum, it became apparent that a basic understanding of the relevant enzymatic reactions in the host erythrocyte is lacking. To acquire the necessary basic knowledge, we have determined the activities of several enzymes involved in hexosamine metabolism in normal human red blood cells. In the present communication we report the results of studies of glucosamine 6-phosphate deaminase (GlcN6-P) using a newly developed sensitive radiometric assay. The mean specific activity in extracts of fresh erythrocytes assayed within 4h of collection was 14.7 nmol/h/mg protein, whereas preparations from older erythrocytes that had been stored at 4 degrees C for up to 4 weeks had a mean specific activity of 6.2 nmol/h/mg. Characterization of the deaminase by chromatofocusing gave a pI of 8.55. The enzyme was optimally active at pH 9.0 and had a Km of 41 microM. The metal chelators EDTA and EGTA were non-inhibitory; however, inhibition was observed in the presence of metal ions, especially Cu2+, Ni2+ and Zn2+. In addition, the deaminase was also inhibited by several sugar phosphates including the reaction product, fructose 6-phosphate.
 ...
PMID:Glucosamine 6-phosphate deaminase in normal human erythrocytes. 757 55

The potential usefulness of ELISA based serological tests to assist in rapid, early and specific diagnosis of tuberculosis was investigated. The materials were selected, based on published data and on our preliminary findings. Initially screening tests were performed using crude antigens such as Purified Protein Derivate (PPD) and a BCG-filtrate. Unfortunately, the results with these antigens were not promising. The specificity of both antigens using sera from 94 healthy controls was 64%. As a consequence of these findings, the crude antigens were excluded from further tests, and the study was continued with purified antigens. The work focused on 2 purified proteins: Antigen 60 (A60), a lipopolysaccharide-protein complex, and P32, a stress protein produced in zinc deprived cultures, identified as Antigen 85 A in the BCG reference system, both isolated from Mycobacterium bovis BCG. The commercial A60 based ELISA and our own P32 based ELISA were used to test a total of 300 sera from HIV positive, negative and unscreened individuals, mainly originating from Burundi. These sera were collected from clinical established cases of pulmonary TB, extrapulmonary TB, and patients with non-tuberculous tropical diseases such as salmonellosis, trypanosomiasis, malaria, etc. and healthy individuals. The A60 based ELISA had a sensitivity of 76.8% for the proven cases of active pulmonary tuberculosis and 61.9% for the extrapulmonary tuberculosis cases. No difference was shown between HIV positive and HIV negative patients. Specificity reached 95.2% for healthy individuals, but dropped to 68.1% when persons with active non-tuberculous tropical diseases were included. Eighty-six percent of the pulmonary cases and 87.7% of the extrapulmonary cases were detected by the ELISA-P32. These findings suggest that this test might be useful as a confirmatory test for the diagnosis of extrapulmonary tuberculosis. Again no difference was noticed between HIV negative and positive patients. The main contraindication for the use of the ELISA-P32 for the diagnosis of tuberculosis is its low specificity: 70.2% with sera from healthy controls and 22.2% for hospitalised patients and persons with non-tuberculous tropical diseases. In a small recent prospective study 4 out of 10 HIV+ persons with no evidence for TB yielded a positive result for the ELISA-P32. Two of them developed pulmonary tuberculosis within 6 months, whereas 2 P32-positives and 6 P32-negatives remained up to now without any manifestations of tuberculosis. The difference was not significant, but the number of cases was limited.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Rapid, early and specific diagnosis of tuberculosis and other mycobacterial diseases in Burundi. 812 78

Periconceptual use of folic acid supplements by women is effective in preventing neural tube defects in the fetus. Folic acid supplements also may prevent atherosclerosis and some malignant neoplasms. Nevertheless, safety concerns have delayed recommendations to increase folic acid consumption by the general population. Among the potential safety issues of folic acid supplementation are (1) difficulty identifying cobalamin deficiency, precipitation of neurologic complications of cobalamin deficiency, and lowering of cobalamin levels; (2) folate neurotoxicity; (3) antagonism of drugs that inhibit folate metabolism; (4) reduced zinc absorption; (5) association with malignant neoplasms; (6) hypersensitivity reactions; and (7) increased susceptibility to malaria. The data that suggest that folic acid supplements are unsafe are weak and consist predominantly of case series and reports. Nevertheless, greater difficulty diagnosing cobalamin deficiency due to "masking" of hematologic abnormalities by folic acid is a potential risk. Strict vegetarians need to be informed that they are at risk of cobalamin deficiency. Physicians need to be aware that routine hematologic indexes have a low sensitivity for cobalamin deficiency, especially in patients who are receiving folic acid supplements. Because no high-quality data exclude specific adverse effects, physicians should be vigilant in identifying detrimental effects when patients increase their consumption of folic acid.
 ...
PMID:How safe are folic acid supplements? 869 61


1 2 3 4 5 6 7 8 9 10 Next >>