Histopathological observation of acquired immunity in skin of hamsters elicited by Necator americanus third-stage infective larvae / 中国地方病学杂志

Objective To obtain acquired immunity evidence in hamsters elicited by third stage hookworm larvae of Necator americanas(NaL3).morphology changes of NaL3 and inflammatory responses in the skin and undedying subcutaneous tissue and muscles of hamsters were observed.Methods Hamsters were immunized subcutaneously with one dose of 150 NaL3 at 2 weeks earlier,and then challenged pereutaneously with 900 NaL3.Skins were excised from post-challenge hamsters at 6,24,72 hours and 1,2 weeks,and then examined under light microscopy.Non-immunized hamsters served as negative controls.Results In non-immunized hamsters the number of NaL3 were 15,33,11.0 and 0 at 6,24,72 hours and 1,2 weeks post-infection.No damaged or dead NaL3 section was observed.All NaL3 exhibited no structural damage and infihrating inflammatory cells were absent from the sunDunding tissues.There were no cutaneous changes.In contrast.the total number of Nak sections in the skin of immunized hamsters were 25,53,15,5 and 4 at 6,24,72 hours and 1,2 weeks post-challenge.Among these NaL3 sections,damaged and dead section number were 0,24,6,0,0 and 0,0,7,5,4.At 24 hours post-challenge the Nak exhibited cutieular swelling and damage.By 72 hours post-challenge pyknosis of the somatic cells nuclei and sparseness or loss of definition in the internal structures of NaL3 were seen.One or two weeks after chanenge,the NaL3 showed severe damage or even dead with remnants.Inflammatory responses including macrophages,epithelioid cells and eosinophils infiltrating and granulomata forming were mainly seen around the NaL3 sections in the skin of immunized hamsters.Conclusions Hamsters initially immunized with NaL3 exhibited obvious acquired immunity protection against percutaneously challenged infection as evidenced by vigorous inflammatory responses in the skin and underlying subcutaneous tissue and muscle.

Comparative study on schizontocidal activity of recrystallized or crude daphnetin against malaria parasites / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To compare the schizontocidal activity of recrystallized or crude daphnetin against malaria parasites in vivo.</p><p><b>METHODS</b>Schizontocidal activity of recrystallized or crude daphnetin at various dosages was assessed in mice infected with Plasmodium berghei ANKA using a "4-day suppress assay".</p><p><b>RESULTS</b>The comparison of the reduction rate of parasitemia caused by either recrystallized or crude dephnetin showed that ED(50) of crude daphnetin was 18.36 mg/kg, with 95% confidence limit of 5.96-56.54 mg/kg while ED50 of recrystallized daphnetin was 11.46 mg/kg, with 95% confidence limit of 8.63-15.22 mg/kg.</p><p><b>CONCLUSION</b>The results indicate that the efficacy of recrystallized daphnetin is 37.6% higher than that of crude daphnetin.</p>