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

The urban area of Dakar, Senegal, contains > 5,000 market-garden wells that provide permanent sites for mosquito larvae, in particular Anopheles arabiensis Patton, the major vector of malaria. A study of the bioecology of mosquito larvae was conducted over 1 yr with a monthly visit to 48 of these wells. Overall, 9,589 larvae were collected of which 80.1% were Culicinae and 11.9% Anophelinae. Larvae from stages III and IV (n = 853) were identified to 10 species. An. arabiensis represented 86% of the anophelines collected and An. ziemanni Grunberg 14%. The most common Culicinae species included Aedeomyia africana Neveu-Lemaire, Culex quinquefasciatus Say, and Mimomyia splendens Theobald. Maximum anopheline abundance was observed at the end of the dry season in June, whereas maximum Culicinae abundance was observed at the end of the rainy season in September. Most wells (67%) did not harbor any An. arabiensis larvae and in the remaining 33% the larval abundance was low, averaging 0.54 larvae in stages III-IV per tray sample. To identify factors that determine the abundance of larvae in these wells, a co-inertia (multivariate) analysis was carried out to account for physicochemical variables (depth, turbidity, temperature, pH, conductivity, Na+, Cl-, HCO3-, CO3--, and NO3- concentrations) and biological variables (abundance of mosquito species, predators [e.g., fish, Dytiscidae, Notonectidae, odonates], molluscs [Bulinus and Biomphalaria], and surface plants [water lettuce, Lemna, and filamentous algae]). The co-inertia analysis indicated that the abundance of An. arabiensis was associated with Cx. quinquefasciatus and Cx. decens for the physiochemical data but was not associated with other mosquito species for floro-faunistic data. The conditions associated with abundant An. arabiensis were warm temperature (28-30 degrees C), clear and not too deep water (< 0.5 m), elevated concentrations of HCO3- and CO3--, low concentrations of NO3- and NaCl, low populations of larvivorous fish and invertebrate predators (notably odonates), the presence of water lettuce, and an absence of Lemna. These results indicate that many contributing factors influence the ecology of the immature stages of An. arabiensis.
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PMID:Ecology of larval mosquitoes, with special reference to Anopheles arabiensis (Diptera: Culcidae) in market-garden wells in urban Dakar, Senegal. 983 85

Serum levels of reactive nitrogen intermediates (RNI; nitrate + nitrite), interferon gamma (IFN gamma) and tumour necrosis factor (TNF) were measured in 177 Papua New Guinean children with different clinical manifestations of malaria. The groups investigated were asymptomatic parasitaemic, mild malaria, cerebral malaria survivors and cerebral malaria non-survivors. The levels of TNF were highest among the cases of cerebral malaria who died and lowest among the asymptomatic parasitaemic children (mean log TNF levels 2.183 pg/mL vs. 1.455 pg/mL; P = 0.001). Similarly, the levels of IFN gamma were highest among the cerebral and lowest among the asymptomatic patients (mean log TNF levels 0.338 pg/mL vs 0.054 pg/mL; P < 0.0001). RNI levels were high among both the asymptomatic parasitaemic group and those who died due to cerebral malaria (mean log RNI levels 1.56 microM vs. 1.412 microM; P = 0.18). The ratio of RNI to TNF, however, was significantly higher among the asymptomatic parasitaemic children and lowest among those who died due to cerebral malaria (mean log (RNI:TNF) ratio 0.118 vs. -0.789; P < 0.001). We concluded that the ratio of serum RNI to serum TNF is a more useful indicator of outcome of falciparum malaria in this population than the absolute levels of either alone.
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PMID:The ratio of reactive nitrogen intermediates to tumour necrosis factor and clinical outcome of falciparum malaria disease. 985 Mar 96

Levels of procalcitonin (ProCT) have been found to be elevated in individuals with severe bacterial infections such as sepsis and peritonitis, and this correlates well with the severity of the disease. Recently, increased levels have been described in melioidosis and Plasmodium falciparum malaria. In this study ProCT levels were measured in 27 Thai patients with complicated malaria before and during/after treatment with artesunate and mefloquine. Initial parasite counts averaged 290,680/microl (range = 533-1,147,040). On admission, ProCT levels were elevated in all but one patient (median = 40 ng/ml, range = 0.04-662, normal values < 0.5 ng/ml). With treatment, levels decreased to 1.3 ng/ml (range = 0.01-6.5). Nitrite/nitrate levels in patients were higher than in controls throughout the study. The ProCT levels correlated with initial parasite density (P < 0.05), which is a marker of disease severity, and with nitrite/nitrate levels (P < 0.05). Based on the changes of ProCT levels over the course of the disease a possible role in the acute-phase reaction seems likely.
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PMID:Serum procalcitonin levels in severe Plasmodium falciparum malaria. 988 89

The effect of febrifugine, the main alkaloidal constituent of an antimalarial crude drug, Dichroa febrifuga Lour., on protective immunity in mice infected with erythrocytic stage Plasmodium berghei NK65 was investigated. Febrifugine was administered orally, at a dose of 1 mg/kg/day, to mice before and/or after they were infected intraperitoneally with 2 x 10(6) parasitized red blood cells. Then, mortality and the levels of parasitemia and plasma NO3- [a degradation product of nitric oxide (NO)] were monitored. Febrifugine significantly reduced the mortality and the level of parasitemia. The plasma NO3- concentration began to rise within 2 days after treatment with febrifugine and declined to normal in 2 days when the mice were treated orally with febrifugine once a day for 3 consecutive days before parasite infection. This antimalarial activity of febrifugine was reduced by both N(G)-monomethyl-L-arginine and aminoguanidine. These results indicate that the increased production of NO by febrifugine plays an important role in host defense against malaria infection in mice.
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PMID:Potentiation by febrifugine of host defense in mice against Plasmodium berghei NK65. 1053 50

The pathogenesis of cerebral malaria is poorly understood. One hypothesis is that activation of microglia and astrocytes in the brain might cause the cerebral symptoms by excitotoxic mechanisms. Cerebrospinal fluid was sampled in 97 Kenyan children with cerebral malaria, 85% within 48 hr of admission. When compared with an age-matched reference range, there were large increases in concentrations of the excitotoxin quinolinic acid (geometric mean ratio cerebral malaria/reference population [95% confidence limits] = 14.1 [9.8-20.4], P < 0.001) and total neopterin (10.9 [9.1-13.0], P < 0.001) and lesser increases in tetra-hydrobiopterin, di-hydrobiopterin, and 5-hydroxyindoleacetic acid. There was no change in tryptophan concentration. In contrast, nitrate plus nitrite concentrations were decreased (geometric mean ratio = 0.45 [0.35-0.59], P < 0.001). There was a graded increment in quinolinic acid concentration across outcome groups of increasing severity. The increased concentration of quinolinic acid suggests that excitotoxic mechanisms may contribute to the pathogenesis of cerebral malaria.
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PMID:Cerebrospinal fluid studies in children with cerebral malaria: an excitotoxic mechanism? 1081 86

Nitrate levels in CSF and sera from 16 coma and 19 noncoma falciparum malaria patients were determined using nitric oxide colorometric assay. The medians (range lower, upper limits) of nitrate in sera of comatose and noncomatose patients were 0.28 (0.11, 1.24) and 0.23 (0.05, 0.87) microM, respectively. The medians of nitrate level in CSF of coma and noncoma cases were 0.09 (0.01, 0.28) and 0.15 (0, 1.18) microM, respectively. There was no difference of nitrate level in sera and CSF from comatose or noncomatose patients compared to that in normal sera and CSF. The amount of nitrate in sera and CSF of both groups was not significantly correlated with coma depth, parasitemia, parasite clearance time and time to recovery. Contrast to our in vitro study using immunoperoxidase staining, we found inducible nitric oside synthase production by brain endothelial cells during 4-24 hours of coculturing with late stage of P. falciparum infected red blood cells. These results suggests that malaria severity can not be differentiated by nitrate level in body fluid.
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PMID:Lack of association between CSF nitrate and sera nitrate in falciparum malaria infection. 1155 75

We have examined IgG and complement factor C3d deposition on erythrocytes by means of the direct Coombs' test (DAT) and looked for an association with the anaemia seen in falciparum malaria in children living in an area of hyperendemic malaria transmission (in Ghana). In one study (in 1997), 53 out of 199 patients had a positive DAT. Of these, 45 samples reacted with anti-C3d antibodies, 2 with anti-IgG and 6 with both reagents. There were significantly lower haemoglobin (Hb)-levels and higher prevalence of spleen enlargement in DAT-positive than in DAT-negative patients. Hb-levels were independently associated with DAT and age. This initial study was designed to investigate the role of intravascular haemolysis (IVH), but we found no association between IVH and either DAT result or anaemia. Because of the risk of selection bias we repeated the study using consecutive enrollment of malaria patients and were able to confirm the results in a total of 49 DAT-positive and 183 DAT-negative patients. This second study (in 1998) was designed to look at the importance of erythrophagocytosis through measurement of plasma neopterin levels and total nitrite and nitrate as markers of NO-release. Both parameters were significantly higher in DAT-positive than in DAT-negative patients (P < 0.001), indicating that complement binding to erythrocytes was associated with macrophage activation. Plasma levels of haptoglobin, interleukin-10 and tumour necrosis factor-alpha did not vary between the groups. The studies support the role of complement activation and erythrophagocytosis in the pathogenesis of anaemia in falciparum malaria in African children.
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PMID:Complement binding to erythrocytes is associated with macrophage activation and reduced haemoglobin in Plasmodium falciparum malaria. 1170 71

The larval habitats of malaria vectors near the Demilitarized Zone of the Republic of Korea (ROK) were sampled from June through September 2000 to determine larval abundance and to identify environmental factors associated with high larval density. Six primary habitats were identified: rice fields, irrigation ditches, drainage ditches, stream pools, irrigation pools, and marshes. Most habitats harbored similar densities of larvae until August and September, when population densities in rice fields declined and those in irrigation pools increased. The primary vector in the ROK, Anopheles sinensis, occurred in water with a wide range of values for environmental factors, including pH, total dissolved solids, percent of surface covered with floating vegetation, and nitrate and phosphate concentrations. No environmental factor or combination of factors were found that were predictive of high larval densities. This study suggests that larval Anopheles are capable of developing in a wide range of stagnant, freshwater habitats in northern Kyunggi Province, ROK.
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PMID:Environmental factors associated with larval habitats of malaria vectors in northern Kyunggi Province, Republic of Korea. 1232 39

In this study, we investigated the role of nitric oxide metabolism and lipid peroxidation in patients with P. vivax malaria. The levels of nitrite and nitrate were analyzed using a procedure based on the Griess reaction and malondialdehyde levels which index of lipid peroxidation was determined by thiobarbituric acid reaction. The levels of nitrite/nitrate and malondialdehyde in patients were higher than controls and found to be statistically significant (p < 0.001). We performed this study to determine whether nitric oxide and lipid peroxidation is produced during blood-stage P. vivax malaria. This present study shows that lipid peroxidation occurs in P. vivax malaria. The levels of nitric oxide are associated with lipid peroxidation in this disease.
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PMID:The role of nitric oxide and lipid peroxidation in patients with Plasmodium vivax malaria. 1251 54

One hundred and five patients with Plasmodium falciparum were included, forty-three with cerebral malaria and sixty-two without cerebral manifestations. The main clinical presentations in cerebral malaria patients were fever (76.4%), pallor (72%), splenomegaly (60.5%), deep coma (39.5%), jaundice (18.6%), pulmonary oedema (13.9%), subconjunctival haemorrhage (13.9%), severe anemia (Hb<5mg/l) (53.5%), hypoglycemia (glucose<40mg/dl) (67.4%) and haemoglobinuria (6.9%) while in non cerebral malaria patients the clinical presentations were fever (83.8%), pallor (67.7%), splenomegaly (66%), jaundice (9.7%), severe anemia (Hb<5gm/dl) (51.6%) and hypoglycemia (glucose<40mg/dl) (3.2%). Nine patients from cerebral malaria group died after admission. Serum level of nitric oxide (nitrite plus nitrate) were assayed for all patients, serum level of nitric oxide were highly significant in patients with cerebral malaria than those without (34.6 +/- 2.3n. mol/ml VS 12.9 +/- 1.3n. mol/ml; P<0.01). In cerebral malaria, nitric oxide levels were highly elevated in patients with deeper coma than those with lighter coma (48.2 +/- 3.1n. mol/ml VS 24.4 +/- 1.3n. mol/ml; P<0.001) and also higher among patients with longer duration of coma (>72 hours) than among patients with shorter duration of coma (<72 hours) (54.5 +/- 2.8 n. mol/ml V.S. 23.6 +/- 3.1n. mol/ml; P<0.001). Also, nitric oxide levels were correlated with clinical outcome, fatal cases (9 patients) having significantly higher nitric oxide levels than survivors (56.2 +/- 3.1 n. mol/ml VS 32.5 +/- 1.3 n. mol/ml; P<0.001). Thus, higher levels of nitric oxide are associated with indices of disease severity and may predict outcome in-patients with cerebral malaria. These data are consistent with the hypothesis that nitric oxide is involved in the pathogenesis of cerebral malaria.
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PMID:Plasma levels of nitric oxide in association with severe Plasmodium falciparum in Yemen. 1256 1


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