Prevalence of Schistosoma haematobium infection among inhabitants of Lowveld, Swaziland, an endemic area for the disease

We carried out a parasitological survey of Schistosoma haematobium infection among the residents of Lowveld Siphofaneni, Swaziland, an area which is devoid of sanitation. Subjects with positive infection were confirmed by the detection of S. haematobium ova in their urine. The intensity of the infection was estimated by calculating the total number of S. haematobium ova present in 10 ml urine specimen (geometric mean intensity; GMI). Overall, the prevalence of S. haematobium infection was 6.1% (18/295) with a GMI of 20.7 (95% CI=9.1~32.2). Female (10.5%, 16/153) had significantly higher prevalence than that in male (1.4%, 2/142) (ORs=8.2, 95% CI=1.8- 36.2, P<0.01); conversely, male had higher GMI (60.0) than that (17.3) in female. The age group of ≤5 yrs (15.3%, 9/59) had significantly higher prevalence than that in age group of ≥19 yrs (2.6%, 3/115) (ORs=0.2, 95% CI=0.04-0.57, P<0.01). The highest GMI of 27.9 (95% CI=7.6~48.2) was also seen in age group of ≤5 yrs.

Enhanced expression of transforming growth factor-beta 1 in inflammatory cells, alpha-smooth muscle actin in stellate cells, and collagen accumulation in experimental granulomatous hepatitis caused by Toxocara canis in mice

Although toxocaral granulomatous hepatitis (TGH) characterized with a dominant-Th2 type immune response is a self-limiting disease, little is known concerning the role of fibrosis-related cytokine transforming growth factor-beta 1 (TGF-beta 1) in pathogenesis of TGH. A detailed histological and quantitatively immunohistochemical analysis of TGF-beta 1, alpha-smooth muscle actins (alpha-SMA), and collagen was performed on the liver tissues from mice infected with Toxocara canis as assessed between day 1 and 42 weeks post-infection (DPI or WPI). TGF-beta1 was detected mainly in infiltrating leukocytes in lesions with strong expressions from 4 to 16 WPI. Larvae per se also exhibited strong TGF-beta 1-like molecule expressions in the trial. Alpha-SMA was detected predominantly in hepatic stellate cells (HSC) which surrounded the lesions with moderate expressions largely throughout the period of the entire experiment. Collagen was observed to accumulate in inflammatory lesions and biliary basement with moderate to strong expressions from 1 WPI onwards in the trial. Since many evidences have indicated that leukocytes have the potential to influence HSC by producing TGF-beta 1 which can affect HSC to increase collagen synthesis in various liver diseases, we may propose that persistently elevated TGF-beta 1 expression in infiltrating leukocytes and active HSC with marked alpha-SMA expressions may contribute to healing of injured sites through up-stimulation of collagen deposition; in contrast, abnormally persistent collagen accumulation may cause irreversible fibrotic injury in the TGH.

Seroepidemiologic survey of Dirofilaria immitis infection among domestic dogs in Taipei City and mountain aboriginal districts in Taiwan (1998-1999)

To estimate the seroprevalence of Dirofilaria immitis infection in domestic dogs in Taiwan, we utilized a commercial ELISA kit (Snap, IDEXX, USA) for detecting circulating antigens released by adult female worms. Serum specimens of 664 domestic dogs sampled from Taipei City in northern Taiwan and 14 mountain aboriginal districts in eastern Taiwan were screened for D. immitis antigens. Multivariate-adjusted odds ratios (ORs) with their 95% confidence intervals (CIs) were estimated by multiple logistic regression analysis. A total of 89 subjects were antigen-positive, giving a seroprevalence of 13.4%, of which the seroprevalence in Taipei City and mountain aboriginal districts were 13.8 and 12.1%, respectively. The mean overall seropositive rates were 6.3% in 1-3-year-old age group, 14.1% in 3-6-year-old age group and 23.7% in the > or =6-year-old age group. The older the age, the higher the seroprevalence (OR=4.6, 95% CI=2.4-9.0 for the > or =6-year-old age group versus 1-3-year-old age group, P<0.001) for all the dogs in the present study. Moreover, seroprevalence was not different between female and male dogs in either Taipei City or mountain aboriginal districts (P>0.05). Also, no significant difference in seroprevalence among dogs between the two geographical areas was found (P>0.05). In the logistic regression analysis, the seroprevalence of D. immitis remained significantly increased with age after multivariate adjustment in the present study. To our knowledge, this is the first report on the status of D. immitis infection in domestic dogs in Taipei City and mountain aboriginal districts in Taiwan to date.

Enhancement of the stability and activity of aspartase by random and site-directed mutagenesis

Enzymatic generation of mutant libraries for random mutagenesis of aspartase gene from E. coli J2 was made. A mutant enzyme with 4-fold increase in aspartase activity was found. It is stable at pH7.5-9.0 (wild-type: pH7.0-8.0); heat stability and alpha-helicity are higher than those of the wild-type. By using site directed mutagenesis, the aspartase was activated by replacement of Lys-126 with an arginine residue. The mutation produced functional alterations without appreciable structure changes. The optimum pH for the mutant enzyme is 8.5. The stable pH range is 7.0-9.0. Heat stability is higher than that of the wild-type one. Activity of the mutant enzyme is about 5-fold as much as that of wild-type one.

Effect of ginsenopolypeptide on the 3H-TdR integration of human blood lymphocyte

This paper reports the study of the effect of ginsenopolypeptide on 3H-TdR integration in normal human blood lymphocytes in vitro with micro-blood culture method of 3H-TdR integration. The results showed that the effect of ginsenopolypeptide on 3H-TdR integration in normal human peripheral blood lymphocytes which can be activated by phytoagglutinin was enhanced at low dosage and inhibited at high dosage, and its stimulating spike was 10(-6) micrograms/ml (P less than 0.01).