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Biomedical subjects

A Haque

Publications and source records attributed to A Haque.

At least 109 records · Page 6Linked to original sources
PubMed1982

Detection of IgE antibodies in onchocerciasis. Possibility of using allergens from Dipetalonema viteae extracts that cross-react with allergenic determinants in crude extracts of Onchocerca volvulus.

The present study reports the presence of Onchocerca volvulus specific IgE in the sera obtained from onchocerciasis patients. About 70% of onchocerciasis patients showed a raised level of O. volvulus specific IgE compared to patients infected either with other human filarids (Loa loa, Wuchereria bancrofti, Brugia malayi) or with other helminths (Schistosoma mansoni, Ascaris lumbricoides, Fasciola hepatica). The O. volvulus specific IgE level was significantly higher in patients exhibiting 'gale filarienne' than in microfilaremic patients or in endemic controls. The total IgE level was significantly raised in the serum samples of all groups of subjects from endemic areas compared to European controls. There was no significant increase in the level of IgE in the onchocerciasis sera when O. volvulus antigen was replaced by the antigens from various helminths in the present assay system (radioallergosorbent test). However, there was a clear evidence of the presence of cross-reacting allergens in the crude extracts from adults of O. volvulus and Dipetalonema viteae (a rodent filarial parasite) because there was a significant reduction in IgE level in onchocerciasis sera following absorption with either O. volvulus or D. viteae sorbents. Moreover, the IgE antibodies in onchocerciasis patients sera recognized the allergens which were present in the somatic extracts of O. volvulus and D. viteae as revealed by radiolabelled anti-IgE.

Allergens↗
PubMed1982

Complement-mediated leukocyte adherence to infective larvae of Dipetalonema viteae (Filarioidea): requirement for eosinophils or eosinophil products in effecting macrophage adherence.

The present study reports the existence of C-mediated adherence of eosinophils and/or macrophages to filarial infective larvae of Dipetalonema viteae. C3 molecules are present on the surface of the parasite, as shown by immunofluorescence studies. Samples of fNRS depleted of AP of complement by treatment with Zymosan A or of factor B by heating at 50 degrees C for 20 min fail to mediate cell adherence to the parasite. In contrast, fNRS inactivated for CP of complement by the chelating agent EGTA retains its activity in mediating cell adherence to the parasite. There is a significant consumption of factor B and AP of complement when infective larvae are incubated in fNHS. Consumption of C4 of the CP of complement is much lower in the same test. The adherence of macrophages cannot occur without the simultaneous presence of eosinophils, whereas eosinophils probably act alone and not in concert with macrophages. The eosinophil adherence is associated with degranulation. The damage is notably enhanced by replacing the spent eosinophil population with a newly obtained population. In the present test system, mast cells did not adhere to filarial larvae even when mast cell-rich populations were used, nor did they effect macrophage adherence when presented in association with the latter. When eosinophil-enriched cell populations containing less than 1% mast cells were used, cell adherence to filarial larvae still occurred, but the presence of 30% mast cells in such cell populations markedly increased both the rate and level of adherence. We suggest that a cell-mediated adherence and destruction dependent upon the activation of complement via AP, without a requirement for specific antibody, may represent a natural mechanism of parasite killing in a nonimmune host.

Animals↗
PubMed1981

Dipetalonema viteae: ultrastructural study on the in vitro interaction between rat macrophages and microfilariae in the presence of IgE antibody.

The in vitro interaction between rat peritoneal macrophages and Dipetalonema viteae microfilariae in the presence of amicrofilaraemic rat immune serum was studied by transmission electron microscopy. The probable sequence of events leading to the killing of D. viteae microfilaria by macrophages is as follows. (a) Rat peritoneal macrophages in the presence of amicrofilaraemic rat immune serum adhere to the parasite surface, (b) the macrophages extend their pseudopodia around the parasite, (c) the 'lysosome-like' granules discharge their contents on to the parasite surface, (d) the lytic activity of these products begins at the parasite surface and (e) subsequent breaking of the microfilarial cuticle occurs, exposing the parasite intracellular material.

Animals↗
PubMed1981

Driving performance of retinitis pigmentosa patients.

The driving performance of 42 patients with retinitis pigmentosa (RP) was compared with that of 87 control subjects. Although the patients with RP were involved in more isolated road accidents than the control group, 50% were not involved in any accident over the most recent 5-year driving period. When the associations between driving performance and case/control status were examined (the number of driving hours per week and driving years being taken into account), differences in the number of accidents between the 2 groups were significant because of a disproportionately high number of accidents caused by a subgroup of female RP patients. No significant correlations were apparent between central visual efficiency or peripheral field efficiency and number of road accidents.

Accidents, Traffic↗
PubMed1981

Detection of circulating antigens in onchocerciasis.

This report describes the presence of circulating Onchocerca volvulus antigens (COA) in sera of patients with onchocerciasis. By using a double diffusion immunoelectrophoresis method, COA could be detected in 24 of 77 sera analyzed (31%). In contrast, when more sensitive assays such as the radioimmunoprecipitation-PEG assay or sandwich radioimmunoassay were used to detect COA, about 75% of the sera from O. volvulus-infected patients were found positive; moreover, a highly significant correlation between the two assays was observed. The parasite specificity of the COA was demonstrated directly by identity reaction with a component of O. volvulus somatic antigens. COA was never found when hyperimmune antisera against other parasite antigenic extracts were used instead of anti-O. volvulus hyperimmune serum. However, when anti-O, volvulus hyperimmune serum was used against sera obtained from patients infected with various other helminths we found a cross-reactivity between COA and the circulating antigens of other human filarids (Wuchereria bancrofti, Loa loa, Brugia malayi), but not with other nematode or trematode parasites (Ascaris lumbricoides, Schistosoma mansoni, Fasciola hepatica). Further immunoelectrophoretic studies demonstrated one precipitin are localized in the cathodic region which seemed specific for COA, which raises the possibility of preparing a monospecific hyperimmune serum to circumvent cross-reactivities.

Adolescent↗
PubMed1980

IgE antibody-mediated cytotoxicity of rat macrophages against microfilaria of Dipetalonema citeae in vitro.

The Fischer rat develops an acquired resistance against circulating microfilariae. Macrophages from the peritoneal washings of normal rats preincubated at 37 degrees C with the sera obtained from rats immune to circulating microfilariae adhered to and kill the microfilaria of Dipetalonema viteae in vitro within 16 to 24 hr. No significant adherence and cytotoxicity was mediated by sera collected from animals with microfilaraemia or from normal rats. Adherence of macrophages to microfilaria was associated with damage to the surface of the larva as revealed by ultrastructural studies. Neither adherence nor cytotoxicity was induced by preincubation of microfilariae, instead of macrophages with immune serum. The serum factor which mediated adherence and cytotoxicity was heat-labile, but was not a complement component. Immune absorption experiments showed that the relevant serum factor resided in the IgE class of antibody. The immune adherence to D. viteae by macrophages is stage-specific because adherence to infective larvae was not observed whether rate macrophages were preincubated in sera obtained from rats immune to microfilariae or in sera collected from animals after exposure to infective larvae.

Animals↗
PubMed1978

Dipetalonema viteae infection in hamsters: enhancement and suppression of microfilaraemia.

Mature male Dipetalonema viteae released a substance(s) which caused enhanced microfilaraemia in infected hamsters. In hamsters implanted with female D. viteae, the microfilaraemia of a subsequent infection was suppressed. The microfilaraemia of female worms implanted in hamsters was depressed within 5 days when the animals were given a further infection with infective larvae.

Animals↗
PubMed1976

Contributions to ecological chemistry CXII1. Balance of conversion of buturon-14C in wheat under outdoor conditions.

The urea herbicide buturon (N-[p-chlorophenyl]-N'-methyl-N'-isobutinyl-urea), 14C-labeled, was sprayed on winter wheat as an aqueous formulation (2.98 kg/ha) under outdoor conditions. Upon harvest (three months after application), a total of 49.2% of the applied radiocarbon was recovered: 2.0% in the plants, 46.9% in the soil, and 0.3% in the leaching water (depth greater than 50 cm); less than 0.1% was in the grains (0.464 ppm). Only about half of the radioactivity present in plants could be recovered under mild extraction conditions; about half of this was unchanged buturon. In straw and husk extracts, the following metabolites were identified by gaschromatography/mass spectrometry:N-(p-chlorophenyl)-N-methyl-O-methyl-carbamate (metabolite I), N-phenyl-N'-formyl-urea (metabolite II), two unstable metabolites giving (p-chlorophenyl)-isocyanate upon purification (metabolites III and IV), N-(p-chlorophenyl)-N'-methyl-N'-isobutenylol-urea (metabolite V), p-chloroformanilide (metabolite VI) and biologically bound p-chloroaniline (metabolite VII). In the root and basal stem extract, the following metabolites were identified by gas chromatography/mass spectrometry: N-(p-chlorophenyl)-O-methyl-carbamate (metabolite VIII) and N-(p-chlorophenyl)-N'-methyl-urea (metabolite IX).

Chromatography, Gas↗