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)

To investigate Fe nutritional indices in malaria infection in children, haematology (blood haemoglobin, plasma ferritin, transferrin, Fe, and transferrin saturation), acute phase markers (albumin and caeruloplasmin) and liver function tests were studied in fifty consecutive cases of severe and mild falciparum malaria, fifty matched controls and twenty-three cases of asymptomatic malaria. Blood haemoglobin and transferrin were lower, while ferritin and transferrin saturation were higher, in groups with symptomatic malaria in comparison with the control group. The differences were greatest with the severest form of the disease. There were no differences between any of the groups in plasma Fe. Plasma transferrin correlated directly with albumin in asymptomatic, mild and severe malaria groups (r 0.48, 0.65 and 0.83; P < 0.05, P < 0.05, P < 0.01 and P < 0.001 respectively), and inversely with caeruloplasmin (r -0.65, -0.34 and -0.43; P < 0.01, P < 0.05 and P < 0.01 respectively). For ferritin, the correlation was inverse with albumin (r -0.65, -0.57 and -0.64; P < 0.01, P < 0.001 and P < 0.001 respectively and direct with caeruloplasmin (r 0.83, 0.21 and 0.49, P < 0.001, NS and P < 0.001 respectively). Multiple regression analysis on data from all patients combined indicated that albumin, and to a lesser extent alanine aminotransferase (EC 2.6.1.2) activity, explained 62 % of the variance in transferrin. Caeruloplasmin, parasite count and albumin explained 59 % of the variance in ferritin, and transferrin and unconjugated bilirubin explained 62 % of the variance in Fe values. In conclusion, these data suggest that low transferrin and high ferritin values are primarily due to the acute phase response. High transferrin saturation and lack of differences in plasma Fe between the groups are probably due to Fe released from lysed erythrocytes. Finally, in both symptomatic and asymptomatic malaria, indices of Fe status can be misleading and may be especially problematic in community studies in malaria-endemic areas where asymptomatic malaria may be common.
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PMID:Influence of malaria on markers of iron status in children: implications for interpreting iron status in malaria-endemic communities. 938 98

The majority of deaths from cerebral malaria occur within 48 h after admission to hospital. Because of the possibility of inadequate treatment within this period, the use of a loading dose of quinine has been proposed. We reviewed clinical and laboratory data for 113 children with cerebral malaria, who were treated with intravenous quinine, 10 mg/kg every 8 h, at Macha Mission Hospital in rural Zambia. In 1990-1991, 39 children were not given a loading dose of quinine while, in 1992-1993, 74 children received a loading dose of 20 mg/kg. Elevated serum iron levels, as reflected in transferrin saturation, were strongly associated with higher mortality. A loading dose of quinine was associated with faster recovery from coma and enhanced clearance of parasitaemia and fever. The loading dose was also associated with trends to lower mortality and higher haemoglobin levels, but these differences were not statistically significant.
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PMID:Loading dose of quinine in African children with cerebral malaria. 986 10

Kidney function was studied in 80 Gambian children with cerebral malaria, 73 children with mild malaria, and in 19 children with other febrile illnesses. Serum creatinine was measured, and the excretion in urine of immunoglobulin G, transferrin, albumin and alpha 1 microglobulin was determined. Twenty-five percent of children with cerebral malaria, and 4% of children with mild malaria had an elevated serum creatinine above 62 mumol/l. Increased urinary protein excretion was frequent: 53% of children with cerebral malaria had a glomerulo-tubular pattern of protein excretion, and 46% a tubular pattern. Median albuminuria was 68 mg/l in children with cerebral malaria, 18 mg/l in children with mild malaria, and 9 mg/l in febrile children with other diseases (P < 0.0001). There was no significant association between the proteinuria and height of fever or the degree of parasitaemia, and there was no significant association between death and signs of renal impairment. Renal involvement is common in children with malaria in The Gambia, with prerenal, glomerular, and tubulo-interstitial factors contributing. It is more pronounced in children with cerebral malaria than in those with mild malaria. However, renal dysfunction is relatively mild and does not indicate a worse prognosis.
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PMID:Renal involvement in Gambian children with cerebral or mild malaria. 1040 76

The severity of anaemia associated with acute, Plasmodium falciparum malaria and the extent to which haemolysis, bone-marrow suppression, and pre-existent iron deficiency contribute to the anaemia were assessed in 102 Indian children aged 2-12 years. Blood haemoglobin (Hb), plasma unconjugated bilirubin and haptoglobin, serum iron and transferrin concentrations and transferrin saturation, red cell morphology and reticulocyte response were investigated in the patients and in 50 control children. Twenty-three patients with severe anaemia (< 70 g Hb/litre) were investigated further, by bone-marrow biopsy followed by iron staining of sections or touch smears of the biopsy material. There was evidence of haemolysis in the malaria cases: in the peripheral blood smears and the significantly higher plasma concentrations of unconjugated bilirubin, lower plasma concentrations of haptoglobin and lower blood concentrations of Hb than those seen in the controls. Haemoglobin concentration correlated directly with haptoglobin (r = 0.489; P < 0.001) and inversely with unconjugated bilirubin in malaria patients (r = -0.526; P < 0.001) but not in controls (r = -0.140 and -0.061, respectively). Parasitaemia (parasites/microliter) was not significantly correlated with Hb, haptoglobin or unconjugated bilirubin. Compared with the earlier samples, follow-up samples from the patients, collected 2 weeks after discharge from hospital and antimalarial therapy, showed significant increase in Hb, haematocrit, haptoglobin and decreases in both total and unconjugated bilirubin. There was evidence of hypercellularity and mild-moderate erythroid hyperplasia, mainly of normoblastic maturation with adequate reticulocyte response, in the bone-marrow samples from the cases of severe anaemia; dyserythropoiesis was only noticed in one case and no stainable iron was detectable in 17 of the 23 cases. These observations indicate that haemolysis is the prime cause of the anaemia seen in acute falciparum malaria, although destruction of parasitised erythrocytes is not the sole cause of the haemolytic process. Bone-marrow suppression appears to have an insignificant role but pre-existent iron deficiency aggravates the severity of the anaemia.
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PMID:Anaemia in acute, Plasmodium falciparum malaria in children from Orissa state, India. 1047 36

The anti-malaria drug primaquine is a weak base which accumulates in endosomes in a protonated form and consequently neutralises the endosomal pH. Bafilomycin A1 prevents endosome acidification by inhibiting the vacuolar proton pump. Although both agents neutralise the endosomal pH, only primaquine has a strong inhibitory effect on recycling of endocytosed proteins to the plasma membrane (Van Weert et al. (1995), J. Cell Biol. 130, 821-834). This suggests that primaquine interferes with a parameter, other than endosomal pH, that is essential for membrane recycling. In the presence of 0.3 mM primaquine, endocytosed transferrin-receptors accumulated intracellularly, but not in the additional presence of bafilomycin A1. Thus, at relative low concentrations proton pump-driven accumulation of primaquine in endosomes was required to inhibit membrane recycling, suggesting that the target of primaquine is associated with endosomes. The inhibitory effect of 1 mM primaquine on transferrin receptor recycling was not reversed by the additional presence of bafilomycin A1, indicating that osmotic swelling of endosomes due to accumulation of protonated primaquine could also not explain its effect. To study endosome swelling morphologically, we introduce a novel technique for fluorescent labelling of endosomes involving HRP-catalysed biotinylation. In the presence of 0.2 mM primaquine endosomal vacuoles with diameters up to 2 microm were observed. Endosome swelling was not observed when in addition to primaquine also bafilomycin A1 was present, supporting the notion that vacuolar proton pump activity lowers the dose response for primaquine. Factors that are crucial for membrane recycling and may be affected by primaquine are discussed.
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PMID:Primaquine interferes with membrane recycling from endosomes to the plasma membrane through a direct interaction with endosomes which does not involve neutralisation of endosomal pH nor osmotic swelling of endosomes. 1092 54

The acute-phase response to infection alters the plasma concentrations of most biochemical measures of iron status, rendering assessment of status difficult. Soluble transferrin receptors (TfR) may be an exception but have not been examined longitudinally during the major metabolic and inflammatory changes which occur during clinical malaria. Blood samples were collected daily during hospitalization, and again at a follow-up 2-6 weeks after discharge, from adult, mainly European, patients (n = 49) who developed uncomplicated Plasmodium falciparum malaria following visits to endemic areas. Parasitaemia and plasma concentrations of ferritin, TfR, C-reactive protein (CRP), alpha 1-acid glycoprotein (AGP) and alpha 1-antichymotrypsin (ACT) were measured. The concentrations of CRP, AGP and ACT correlated highly (P < 0.001) with each other and with plasma ferritin, and were significantly higher (P < 0.05) at all time points in hospital compared to the follow-up. TfR concentration correlated negatively and significantly (P < 0.05) with AGP and CRP but not with ACT or ferritin, and was significantly lower (around 30%) at all time points in hospital compared to follow-up, although in only 1 subject did it ever fall outside the normal reference range. In areas where both iron deficiency and clinical episodes of malaria are common, plasma TfR values need to be interpreted cautiously as indicators of iron status.
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PMID:Impact of acute malaria on plasma concentrations of transferrin receptors. 1097 4

Multiple drug resistance is a significant problem in small-cell lung cancer (SCLC). Artemisinin (ART) is a natural product used to treat drug-resistant malaria. The drug is effective because the Fe2+ present in infected erythrocytes acts non-enzymatically to convert ART to toxic products. We tested the effects of ART on drug-sensitive (H69) and multi-drug-resistant (H69VP) SCLC cells, pretreated with transferrin (TF) to increase the intracellular Fe2+ level. Antibody staining followed by flow cytometry analysis showed twice the level of TF receptors on the H69VP as compared to the H69 cells. Low doses of ART were cytotoxic to SCLC cells. The cytotoxicity of ART for H69VP cells (IC50=24 nM) was ten-fold lower than for H69 cells (IC50=2.3 nM), indicating that ART is part of the drug resistance phenotype. Pretreatment of H69 cells with 220-880 nM TF did not alter the IC50 for ART. However, in the ART-resistant H69VP cells, pretreatment with TF lowered the ART IC50 to near drug-sensitive levels (IC50=5.4 nM after 4 h pretreatment with 880 nM TF). Desferrioxamine (5 microM) inhibited the effect of TF on the IC50 for ART in drug-resistant cells but did not have an effect on ART cytotoxicity in drug-sensitive cells. DNA fragmentation as measured by ELISA occurred within ART-treated cells, with kinetics indicating apoptosis rather than necrosis. This was confirmed by TUNEL staining. These data indicate the potential use of ART and TF in drug-resistant SCLC.
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PMID:Transferrin overcomes drug resistance to artemisinin in human small-cell lung carcinoma cells. 1188 69

The aim of the present study is to evaluate the status of plasma essential trace elements selenium (Se), zinc (Zn), copper (Cu), and iron (Fe) concentrations and their related acute-phase proteins, ceruloplasmin (Cp), ferritin, transferrin (Tf), and albumin levels in patients with vivax malaria. Plasma Cu and Zn concentrations were determined by atomic absorption spectrometry (AAS). Se concentrations were determined by graphite furnace AAS. Fe, Cp, Tf, and albumin levels were determined by colorimetric methods. Plasma Se, Fe, and albumin levels were found to be significantly lower (p < 0.01, p < 0.001, and p < 0.05, respectively) and Cu, Cp, and ferritin levels and Cu/Zn ratios were significantly higher (p < 0.001, p < 0.001, p < 0.001, and p < 0.05, respectively) in patients when compared with those of healthy subjects. Plasma, Tf, and Zn levels were not found to be significantly different (p > 0.05) in patients and controls. There were positive important correlations between Cu and Cp (r = 0.908, p < 0.001), Zn and albumin (r = 0.633, p < 0.001), and negative correlations between Fe and ferritin content (r = -0.521, p < 0.05) and Fe and Tf (r = -0.616, p < 0.01) in the patients group. Our findings demonstrated that plasma essential trace elements Se, Cu, and Fe change, but these changes might be dependent on acute-phase proteins, which were regulated as a part of defense strategies of the organism, induced by hormonelike substances.
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PMID:Essential trace elements selenium, zinc, copper, and iron concentrations and their related acute-phase proteins in patients with vivax malaria. 1611 42

In laboratory medicine an observed value of a biological analyte may be compared with previously observed values from an appropriate reference population. A reference range for serum transferrin receptor concentration has not been established for Zimbabwean children. We prospectively studied 208 children aged 3-60 months who were residents of Harare, a non-malaria and non-hookworm endemic area, and who attended a well-child clinic. Anthropometric measurements were calculated, complete blood counts performed and serum concentrations of ferritin and transferrin receptors determined. A final group of 83 pre-school children with no apparent illness was used to determine the serum transferrin receptor concentration reference interval after excluding individuals with abnormal clinical and laboratory investigations. The central 95 percentile interval for transferrin receptors after eliminating factors that are known to affect serum transferrin receptors was 3.9-9.5 mg/L. Children, aged < or =24 months had a lower reference range than children >24 months old. This study provides an estimate of the serum transferrin receptor reference intervals in African children using the Ramco Laboratories, Stafford, TX assay kit.
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PMID:Reference intervals of serum transferrin receptors in pre-school children in Zimbabwe. 1749

Artemisinin and its derivatives are well known antimalaria drugs and particularly useful for the treatment of infection of Plasmodium falciparum malaria parasites resistant to traditional antimalarials. Artemisinin has an endoperoxide bridge that is activated by intraparasitic heme-iron to form free radicals, which kill malaria parasites by alkylating biomolecules. In recent years, there are many reports of anticancer activities of artemisinins both in vitro and in vivo. Artemisinins have inhibitory effects on cancer cell growth, including many drug- and radiation-resistant cancer cell lines. The cytotoxic effect of artemisinin is specific to cancer cells because most cancer cells express a high concentration of transferrin receptors on cell surface and have higher iron ion influx than normal cells via transferrin mechanism. In addition, some artemisinin analogs have been shown to have antiangiogenesis activity. Artemisinin tagged to transferrin via carbohydrate chain has also been shown to have high potency and specificity against cancer cells. The conjugation enables targeted delivery of artemisinin into cancer cells. In this review, we discuss the anticancer activities and mechanisms of action of artemisinins and the transferrin-conjugate.
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PMID:Anticancer properties of artemisinin derivatives and their targeted delivery by transferrin conjugation. 1794 55


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