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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rates of acquisition and loss of parasitic infection in the vector host of Wuchereria bancrofti were estimated using a new method. The age of parasitic infections was estimated from the abdominal condition, determined on the basis of Sella's stages of blood digestion and ovary development, and parity of the vector host and larval stages of the parasite. A negative exponential relationship between age and number of W. bancrofti infections provided estimated daily losses of 25.3% and 33.2% of the initial infection from the resting and biting populations, respectively, of the mosquito Culex quinquefasciatus. The rates per day of acquisition of infection estimated from resting and biting female Cx. quinquefasciatus were found to be 9.6% and 8.6%, respectively. The mean minimum developmental time for W. bancrofti infective larvae estimated from the natural resting and biting populations were 8.9 +/- 1.41 (+/- SEM) and 8.33 +/- 0.85 days, respectively, which was somewhat less than the duration observed under laboratory conditions. Comparisons of the estimates (mean age, rates of acquisition, and loss of infections) based on the resting and biting data suggest that the rates are independent of the method of collecting mosquitoes.
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PMID:Rates of acquisition and loss of Wuchereria bancrofti infection in Culex quinquefasciatus. 807 59

Patent infection with Wuchereria bancrofti is associated with increased levels of filaria-specific IgG4 and IgE. In vitro quantification of filaria-specific IgE is hampered by its small proportion in serum relative to other isotypes and by potential competition with IgG4 for the same epitopes on parasite antigens. To determine if IgG4 or other isotypes inhibit the detection of parasite-specific IgE, total IgE was affinity purified prior to filaria-specific IgE enzyme-linked immunosorbent assay. Briefly, anti-human IgE mouse monoclonal antibody 6H10 was coupled to Affigel, and 50 microliters of patient serum was incubated on microcolumns for 16 hr. Total IgE was eluted with 25 mM triethylamine (pH 11.2) and levels of total and filaria-specific IgE and total IgG4 were assessed in the filtrates and eluates. Sera from 14 patients with W. bancrofti microfilaremia (Mf+) and 17 amicrofilaremic patients with chronic pathology (CP) were assayed. Filtrates and eluates were devoid of IgE and IgG4, respectively. The average yield of total IgE in the eluates was 70% (SEM = 6.5; range 21-100%) of that measured in the serum. Antifilarial IgE levels in column eluates were significantly higher in serum samples from CP patients than Mf+ patients. Antibody inhibition of IgE was assessed by comparing the levels of anti-filarial IgE detected in eluates and serum. Evidence for antibody-mediated inhibition of IgE detection was obtained with 2/2 samples from Indian tropical pulmonary eosinophilia patients, but only 2/14 and 4/17 Mf+ and CP patients, respectively.
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PMID:Immunopurification and measurement of IgE in serum samples from bancroftian filariasis patients. 862 93

Light microscopy analyses of microfilariae of Wuchereria bancrofti treated with DEC revealed a striking loss of the microfilarial sheath. However, no effect was observed on microfilariae of Litomosoides chagasfilhoi treated with DEC. For quantitative analyses microfilariae of W. bancrofti were processed for SEM. Controls, which have not received DEC, had 29.8% of exsheathed microfilariae. Conversely, the number of exsheathed microfilariae increased as increased DEC concentrations: 5 microg/ml (75.9%), 10 microg/ml (80.1%), and 50 microg/ml (87.7%). After DEC treatment some of sheathed microfilariae showed a wrinkled surface, and in some microfilariae, sheaths were observed being liberated almost intact from the larvae surface. But, frequently residues of the lost sheath over the surface were also observed. No damage was observed in the microfilariae cuticle. The present work shows quantitative data on the loss of the microfilarial sheath of W. bancrofti after treatment with DEC. Since no loss of microfilarial sheath was observed in microfilariae of L. chagasfilhoi submitted to the same conditions, DEC may present different mechanisms of action for distinct filarial species.
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PMID:Diethylcarbamazine induces loss of microfilarial sheath of Wuchereria bancrofti. 1468 Sep 24