[Early constant observation of the effect of deferoxamine mesylate on improvement of vascularized bone regeneration in SD rat skull critical size defect model].

OBJECTIVE: To investigate the effect of local administration of deferoxamine mesylate (DFO) on vascularization and osteogenesis and its ability to maintain the activity of hypoxia inducible factor-1α (HIF-1α), by constantly observing early changes of vessel-like structures and bone tissues during bone defects healing. METHODS: Skull critical bone defect models were constructed on a total of thirty male SD rats (6-8 weeks old). The rats were randomly divided into experimental group (DFO group) or control group (normal saline group). 300 µL 200 µmol/L DFO solution or normal saline was locally injected on the 4th day after the defect was made. On the 5th, 7th, 10th, 14th, and 28th days after surgery, three rats in each group were sacrificed respectively. HE staining and Masson staining were performed to observe new bone formation and mineralization. HIF-1α immunohistochemistry staining was performed to examine relative expression of protein. Qualitative analysis and comparation were performed by t-tests on relative expression of HIF-1α, numbers of blood vessels and percentages of mineralization tissues of new bone areas. RESULTS: On the 5th, 7th, 10th, 14th and 28th days after surgery, the average numbers of blood vessels were 30.40±12.15, 62.00±17.87, 73.43±15.63, 40.00±7.84, 48.71±11.64 in the DFO group, and 18.75±6.63, 19.13±2.80, 51.35±16.21, 27.18±7.32, 30.88±13.43 in the control group. The number of blood vessels in the DFO group was significantly higher than that of the control group at each time point (P < 0.05). The mass of new bone in the DFO group was higher than that in the control group on the 14th and 28th days after surgery. The percentage of mineralization tissues of new bone area on the 14th and 28th days after injection were (27.73±5.93)% and (46.53±3.66)% in the DFO group, and (11.99±2.02)% and (31.98±4.22)% in the control group. The percentage of mineralization tissues in the DFO group was significantly higher than that of the control group at each time point (P < 0.001). The relative expression of HIF-1α in the DFO group compared with the control group was 2.86±0.48, 1.32±0.26, 1.32±0.32, 1.28±0.38 and 1.05±0.34 on the 5th, 7th, 10th, 14th and 28th days, with significant expression difference on the 5th day (P < 0.01). CONCLUSION: Use of DFO in bone defects promotes vascularization and osteogenesis in the defect area, and maintains the protein activity of HIF-1α temporarily.

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.

Seroprevalence of Toxocara canis infection among children in Swaziland, southern Africa.

As there appeared to be no data available on Toxocara canis infection in the children of Swaziland, a serological survey of T. canis infection was recently conducted among 92 children aged 3-12 years from rural slums in the low- and middle-veld. A child was considered seropositive if, in western blots based on the excretory-secretory antigens of larval T. canis, his or her serum gave a positive result when diluted 1 : 64. Forty-one (44.6%) of the children were found seropositive. There were no statistically significant differences in seroprevalence between the 49 boys and 43 girls investigated (46.9% v. 41.8%) or between the eight subjects aged 12 years and the 47 aged < or = 5 years (62.5% v. 38.3%); the corresponding odds ratios were 0.81 (95% confidence interval=0.36-1.86; P=0.62) and 2.69 (95% confidence interval=0.57-12.62; P=0.20), respectively. The 66 subjects from the middleveld were, however, significantly more likely to be seropositive than the 26 subjects from the lowveld (54.5% v. 19.2%; odds ratio=5.04, with a 95% confidence interval of 1.70-14.98; P<0.01). It seems likely that T. canis infection is common among the children who live in slums in Swaziland, particularly in the country's middleveld, probably as the result of poor hygiene and poor sanitation.

Sero-epidemiology of Toxocara canis infection among aboriginal schoolchildren in the mountainous areas of north-eastern Taiwan.

A sero-epidemiological study of Toxocara canis infection was conducted among Atayal schoolchildren (aged 7-12 years) residing in the mountainous areas of north-eastern Taiwan. The 73 children investigated were each checked for anti-Toxocara IgG, in ELISA based on the larval excretory-secretory antigens of T. canis larvae. A short, self-administered questionnaire was then used to collect relevant information from each subject, including data on the keeping of dogs, playing in soil, eating raw vegetables, and whether the subjects normally washed their hands before eating. Once the seropositive children had been identified, odds ratios (OR), with their corresponding 95% confidence intervals (CI) and P-values, were calculated for each potential risk factor. When diluted 1:64, sera from 42 (57.5%) of the children gave a positive result in the ELISA, indicating that these 42 children were seropositive for T. canis infection. Seropositivity did not appear to be associated with the age or gender of the subject, the eating of raw vegetables, or the regular failure to wash hands prior to a meal. Compared with the other subjects, however, those who admitted living in a household where dogs were kept (OR = 3.79; CI = 1.23-11.69; P = 0.02) or playing in soil (OR = 3.00; CI = 1.10-8.16; P = 0.03) appeared at increased risk of seropositivity.

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).