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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This paper describes the fine structure of the sporogonic development of Plasmodium falciparum in its natural vector Anopheles gambiae (Species A) as seen by scanning and transmission electron microscopy. The parasite was derived from naturally infected volunteers and the vector maintained under natural conditions at the MRC Laboratories, Fajara, The Gambia. Sporogonic development of P. falciparum is similar to that described for other Plasmodium spp. There are however greater similarities between P. falciparum and the avian malaria parasites, than those mammalian (primarily rodent) species described to date--particularly with respect to mitochondrial development, crystalloid morphology and nucleolar organization. Nuclear development is similar to that of the murine malaria parasites, but reconstruction of complete mitotic spindles from serial sections suggest the haploid genome of P. falciparum contains 14 chromosomes compared to eight to ten in the murine plasmodia. Sporoblast formation involves a unique process of cleft formation based on the expansion of the cisternal space of the endoplasmic reticulum. Sporozoite budding is almost exclusively confined to these inner membrane surfaces and results in a characteristic sporozoite distribution in the oocyst. High resolution scanning electron microscopy of free sporozoites provides the first surface view of the micropore of Plasmodium.
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PMID:An ultrastructural study of the sporogonic development of Plasmodium falciparum in Anopheles gambiae. 36 85

The nephrotic syndrome in Nigerian children is known to be largely associated with the endemicity of quartan malaria. Routine thyroid function studies were carried out on 24 children with clinical and biochemical evidence of the nephrotic syndrome. The children, aged four to 14 years, were all in the active phase of their disease, presenting with facial and pedal oedema and ascites. There was severe hypoalbuninaemia [mean (S.E.); 19.2 (1.1) g/l], hypercholesterolaemia; 10.5 (1.0) mmol/l and severe albuminuria ranging from 1 to 10 g/l. There was no clinical evidence of thyroid disease. The results of thyroid function tests in these children were compared with those of 181 apparently healthy children of the same age range. The mean total serum thyroxine levels (S.E.) were 118.3 (2.6) and 50.0 (6.4) nmol/l in controls and patients, respectively; T3 resin uptake values were 29.8 (0.2)% and 33.1 (1.2)%; the free thyroxine index (FTI) was 34.7 (0.8) and 16.7 (1.9) while thyrotropin (TSH) levels were 4.8 (0.2) and 10.6 (1.0) mU/l (IRP. MRC 68/38), respectively. The findings of low levels of thyroxine and FTI in association with high levels of TSH suggest that a state of primary hypothyroidism exists in these nephrotic children.
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PMID:Biochemical hypothyroidism in Nigerian children with nephrotic syndrome. 619 15

DDT is a pesticide used in malaria-control programmes throughout the world. Its potential carcinogenicity was studied in MRC Porton rats (Wistar-derived) which received dietary concentrations of 0, 125, 250 and 500 parts per million DDT (technical-grade) for life. The treatment had no adverse effects on body growth or survival rate. Various types of tumours were observed in animals in all groups: exposure to DDT resulted in statistically significant increased incidence of liver-cell tumours only in female treated rats; one such tumour was observed in control rats. No metastases of these tumours were found.
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PMID:Effects of long-term intake of DDT on rats. 628 Mar 47

A longitudinal study of malaria incidence recorded at malaria clinic of MRC, Shankargarh, during 1988-1991 showed the immense popularity of the clinic in quarry area. In clinical cases, SPR and SfR gradually increased from 45.6 and 18.2 in 1988 to 52.5 and 34.5 respectively in 1991. Increase in malaria cases during the reporting period was mainly contributed by P. falciparum cases. Peaks of vivax and falciparum malaria were recorded in September and October respectively. Extended transmission in Shankargarh region might be attributed to the influx of quarry labourers after post-monsoon season. SfR for 0 to 1-year age group malaria cases was found to be relatively low as compared to the higher age groups. Only 56 per cent of malaria-positive patients reported in the clinic had fever.
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PMID:Malaria in Shankargarh PHC, Allahabad District (U.P.): a clinical report. 831 15

To identify new leads for the treatment of Plasmodium falciparum malaria, we screened a panel of serotonin (5-hydroxytryptamine [5HT]) receptor agonists and antagonists and determined their effects on parasite growth. The 5HT1A receptor agonists 8-hydroxy-N-(di-n-propyl)-aminotetralin (8-OH-DPAT), 2,5-dimethoxy-4-iodoamphetamine, and 2,5-dimethoxy-4-bromophenylethylamine inhibited the growth of P. falciparum in vitro (50% inhibitory concentrations, 0.4, 0.7, and 1.5 microM, respectively). In further characterizing the antiparasitic effects of 8-OH-DPAT, we found that this serotonin receptor agonist did not affect the growth of Leishmania infantum, Trypanosoma cruzi, Trypanosoma brucei brucei, or Trichostrongylus colubriformis in vitro and did not demonstrate cytotoxicity against the human lung fibroblast cell line MRC-5. 8-OH-DPAT had similar levels of growth inhibition against several different P. falciparum isolates having distinct chemotherapeutic resistance phenotypes, and its antimalarial effect was additive when it was used in combination with chloroquine against a chloroquine-resistant isolate. In a patch clamp assay, 8-OH-DPAT blocked a P. falciparum surface membrane channel, suggesting that serotonin receptor agonists are a novel class of antimalarials that target a nutrient transport pathway. Since there may be neurological involvement with the use of 8-OH-DPAT and other serotonin receptor agonists in the treatment of falciparum malaria, new lead compounds derived from 8-OH-DPAT will need to be modified to prevent potential neurological side effects. Nevertheless, these results suggest that 8-OH-DPAT is a new lead compound with which to derive novel antimalarial agents and is a useful tool with which to characterize P. falciparum membrane channels.
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PMID:5HT1A serotonin receptor agonists inhibit Plasmodium falciparum by blocking a membrane channel. 1463 87

Thirty-three plants commonly used in West tropical Africa by traditional healers for the treatment of malaria were collected and ethanolic extracts were obtained by decoction. The antiplasmodial activity of extracts was evaluated in vitro against the chloroquine-resistant FcB1 strain of Plasmodium falciparum. Cytotoxicity was determined on the human MRC-5 and the rat L-6 cell lines. Of the 33 plant extracts, eight (24.5%) showed significant antimalarial activity (IC(50) values ranging from 2.3 to 13.7 microg/ml), 14 (42.5%) weak activity (IC(50) values ranging from 15 to 50 microg/ml) and 11 (33%) appeared inactive (IC(50) values >50 microg/ml). Five plants were of particular interest, associating good antiplasmodial activity and weak cytotoxicity. These five included Nauclea latifolia with known antiplasmodial activity and four, Fagara macrophylla, Funtumia elastica, Phyllanthus muellerianus and Rauvolfia vomitoria, for which the description of antiplasmodial activity is entirely novel.
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PMID:In vitro antiplasmodial activity and cytotoxicity of 33 West African plants used for treatment of malaria. 1581 60

Twenty-seven species of native Brazilian Cerrado plants commonly used by traditional healers to treat malaria and other diseases were collected and 204 hexanic and ethanolic extracts were obtained by maceration. The antiplasmodial activity of the extracts was tested in vitro against a chloroquine resistant strain (FcB1) of Plasmodium falciparum, and cytotoxicity against the cell lines L-6 of rats and MRC-5 of human was evaluated. Thirty-two extracts showed significant inhibition rates of Plasmodium falciparum growth and of these six showed cytotoxicity against the cell lines. The strongest antiplasmodial activity was found for the hexanic extracts of Xylopia aromatica root wood (IC(50)=4.7 microg/ml), Xylopia emarginata root bark (IC(50)=4.9 microg/ml), Casearia sylvestris var. lingua leaves, stem wood and stem bark, and root wood and root bark (IC(50) values from 0.9 to 2.3 microg/ml), and Cupania vernalis leaves (IC(50)=0.9 microg/ml); and for the ethanolic extract of Aspidosperma macrocarpon root bark (IC(50)=4.9 microg/ml). However, the best selectivity towards Plasmodium falciparum was observed for the hexanic root bark extract of Matayba guianensis (IC(50) on Plasmodium falciparum=6.1 microg/ml, SI=16.4 for MRC-5) and the ethanolic root bark extract of Aspidosperma macrocarpon (IC(50) on Plasmodium falciparum=4.9 micro/ml, SI=16.2 for MRC-5).
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PMID:In vitro antiplasmodial activity of Brazilian Cerrado plants used as traditional remedies. 1709 51

Diploid cells (WI-38, MRC-5) vaccines have their origin in induced abortions. Among these vaccines we fi nd the following: rubella, measles, mumps, rabies, polio, smallpox, hepatitis A, chickenpox, and herpes zoster. Nowadays, other abortion tainted vaccines cultivated on transformed cells (293, PER.C6) are in the pipeline: flu, Respiratory Syncytial and parainfluenza viruses, HIV, West Nile virus, Ebola, Marburg and Lassa, hepatitis B and C, foot and mouth disease, Japanese encephalitis, dengue, tuberculosis, anthrax, plague, tetanus and malaria. The same method is used for the production of monoclonal antibodies and other proteins, gene therapy and genomics. Technology enables us to develop the aforementioned products without resorting to induced abortion. Full disclosure of the cell origin in the labelling of vaccines and other products must be supported. There are vaccines from non-objectionable sources which should be made available to the public. When no alternative vaccines exist, ethical research must be promoted. Non-objectionable sources in the production of monoclonal antibodies, gene therapy and genomics must be encouraged. It is not be consistent to abstain from products originated in embryonic stem cells and at the same time approve of products obtained from induced abortions. It is of paramount importance to avoid that induced abortion technology seeps into every field of Medicine.
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PMID:[Vaccines, biotechnology and their connection with induced abortion]. 1861 Oct 78

A new class of copper(II) nanohybrid solids, LCu(CH(3)COO)(2) and LCuCl(2), have been synthesized and characterized by transmission electron microscopy, dynamic light scattering, and IR spectroscopy, and have been found to be capped by a bis(benzimidazole) diamide ligand (L). The particle sizes of these nanohybrid solids were found to be in the ranges 5-10 and 60-70 nm, respectively. These nanohybrid solids were evaluated for their in vitro antimalarial activity against a chloroquine-sensitive isolate of Plasmodium falciparum (MRC 2). The interactions between these nanohybrid solids and plasmepsin II (an aspartic protease and a plausible novel target for antimalarial drug development), which is believed to be essential for hemoglobin degradation by the parasite, have been assayed by UV-vis spectroscopy and inhibition kinetics using Lineweaver-Burk plots. Our results suggest that these two compounds have antimalarial activities, and the IC(50) values (0.025-0.032 microg/ml) are similar to the IC(50) value of the standard drug chloroquine used in the bioassay. Lineweaver-Burk plots for inhibition of plasmepsin II by LCu(CH(3)COO)(2) and LCuCl(2) show that the inhibition is competitive with respect to the substrate. The inhibition constants of LCu(CH(3)COO)(2) and LCuCl(2) were found to be 10 and 13 microM, respectively. The IC(50) values for inhibition of plasmepsin II by LCu(CH(3)COO)(2) and LCuCl(2) were found to be 14 and 17 microM, respectively. Copper(II) metal capped by a benzimidazole group, which resembles the histidine group of copper proteins (galactose oxidase, beta-hydroxylase), could provide a suitable anchoring site on the nanosurface and thus could be useful for inhibition of target enzymes via binding to the S1/S3 pocket of the enzyme hydrophobically. Both copper(II) nanohybrid solids were found to be nontoxic against human hepatocellular carcinoma cells and were highly selective for plasmepsin II versus human cathepsin D. The pivotal mechanism of antimalarial activity of these compounds via plasmepsin II inhibition in the P. falciparum malaria parasite is demonstrated.
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PMID:Antimalarial evaluation of copper(II) nanohybrid solids: inhibition of plasmepsin II, a hemoglobin-degrading malarial aspartic protease from Plasmodium falciparum. 1994 19

Quassia amara L. (Family Simaroubaceae) is known to have several medicinal properties including the activity against malaria. An HPLC method was employed for purification of the biologically active quassinoids; quassin (Q) and neo-quassin (NQ), further characterized by MALDI-TOF analyses. Purified Q, NQ and the crude bark extract (S1) along with artesunate (AS) were studied for their in vitro anti-plasmodial activity. The in vivo toxicity studies at intraperitoneal doses with higher concentrations of the crude bark extract (S1) in Balb/C mice ruled out the apprehension of toxicity. Interaction studies between the test compounds among themselves (Q+NQ) and individually with artesunate (AS+Q, AS+NQ), were carried out in vitro at four ratios (1:5, 1:2, 2:1 and 5:1) on chloroquine sensitive (MRC-pf-20) and resistant (MRC-pf-303) strains of Plasmodium falciparum. The crude bark extracts of Q. amara exhibited higher P. falciparum inhibitory activity (IC(50)=0.0025 microg/ml) as compared to that of the isolated compounds, quassin (IC(50)=0.06 microg/ml, 0.15 microM), neo-quassin (IC(50)=0.04 microg/ml, 0.1 microM) and also to the positive control, artesunate (IC(50)=0.02 microg/ml, 0.05 microM). The in vitro drug interaction study revealed the compounds, quassin and neo-quassin to be additive to each other. At lower ratios, artesunate was found to be a potential combination partner with both the compounds. It was interesting to note that none of the combinations exhibited antagonistic interactions. This phenomenon offers the opportunity for further exploration of novel therapeutic concentrations and combinations.
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PMID:Plasmodium falciparum: in vitro interaction of quassin and neo-quassin with artesunate, a hemisuccinate derivative of artemisinin. 2003 57


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