Trends and Challenges Regarding the Source-Specific Health Risk of PM2.5-Bound Metals in a Chinese Megacity from 2014 to 2020.

Identifying the health risk of PM2.5 is essential for urban air pollution control. In 2013, China announced the ever-strict national Air Pollution Prevention and Control Action Plan, and its health benefit should be evaluated to provide reference for future policymaking. In this study, we conducted a seven-year (2014-2020) continuous observation of PM2.5 in Shenzhen, the third largest city in China, which has relatively good air quality. The results showed that the annual mean PM2.5 and total concentration of 21 associated metals dropped from 37.7 to 18.5 µg/m3 and from 2.4 to 1.1 µg/m3, respectively. Combining methods for source apportionment and health risk assessment, we found that the total carcinogenic risk (CR) of five hazardous metals (Cd, Cr, Ni, Co, and Pb) showed a clear decreasing trend. However, the total CR (1.8 × 10-6) in 2020 still exceeded the widely acceptable risk level (i.e., 1 × 10-6), with the primary contributor changing from industrial emissions (61%) to vehicle emissions (63%). Further analysis indicated that the CR of vehicles mainly came from Cr and Ni released by braking and tire wearing and has fluctuated in recent years, highlighting a great challenge of controlling nonexhaust emissions of vehicles (including electric cars) in the future.

Soil dust as a potential bridge from biogenic volatile organic compounds to secondary organic aerosol in a rural environment.

The role of coarse particles has recently been proven to be underestimated in the atmosphere and can strongly influence clouds, ecosystems and climate. However, previous studies on atmospheric chemistry of volatile organic compounds (VOCs) have mostly focused on the products in fine particles, it remains less understood how coarse particles promote secondary organic aerosol (SOA) formation. In this study, we investigated water-soluble compounds of size-segregated aerosol samples (0.056 to >18 µm) collected at a coastal rural site in southern China during late summer and found that oxygenated organic matter was abundant in the coarse mode. Comprehensive source apportionment based on mass spectrum and 14C analysis indicated that different from fossil fuel SOA, biogenic SOA existed more in the coarse mode than in the fine mode. The SOA in the coarse mode showed a unique correlation with biogenic VOCs. 13C and elemental composition strongly suggested a pathway of heterogeneous reactions on coarse particles, which had an abundant low-acidic aqueous environment with soil dust to possibly initiate iron-catalytic oxidation reactions to form SOA. This potential pathway might complement understanding of both formation of biogenic SOA and sink of biogenic VOCs in global biogeochemical cycles, warrantying future relevant studies.

Administrative village-based spatial distribution specificity of Oncomelania hupensis and its relationship with water systems in Hubei Province / 中国血吸虫病防治杂志

Objective To investigate the spatial distribution of Oncomelania hupensis snail habitats at the administrative village scale in schistosomiasis-endemic areas of Hubei Province, so as to provide scientific bases for precise control of O. hupensis snails in the province. Methods Data regarding snail distribution at the village level in Hubei Province in 2017 were collected to create a spatial analysis database of snail distribution in Hubei Province. The spatial aggregations of O. hupensis distribution were analyzed using Moran’s I index and Local Moran’s I index. In addition, the distances from schistosomiasis-endemic villages to the Yangtze River were captured using the software ArcGIS 13.0, and their correlations with area of snail habitats were examined with the Spearman correlation method. Results O. hupensis snails were mainly distributed in 5 450 endemic villages from 63 counties of 13 cities in Hubei Province in 2017. The global spatial autocorrelation analysis showed spatial aggregations in the areas of historically accumulated snail habitats, current areas of snail habitats, areas of snail habitats outside the embankment and snail habitats inside the embankment (all Z Scores > 0, all P values < 0.05), and no spatial aggregation was seen in the areas of snail habitats in hilly areas (Z Score > 0, P > 0.05). There were four types of spatial distribution of historically accumulated areas of snail habitats, areas of current snail habitats, areas of snail habitats outside the embankment and snail habitats inside the embankment, including the high-high type (H-H type), high-low type (H-L type), low-high type (L-H type) and random distribution type, and a high percentage of the H-H type was found. There were 340, 125 and 110 endemic villages with the H-H type of areas of historically accumulated snail habitats, current areas of snail habitats and areas of snail habitats outside the embankment, and these villages were mainly concentrated in Wuhan and Jingzhou cities, with almost consistent spatial aggregation locations. There were 319 endemic villages with the H-H type of distribution of snail habitats inside the embankment, which were mainly distributed in Jingzhou, Xiaogan and Huangshi cities. In addition, the areas of historically accumulated snail habitats, current areas of snail habitats and areas of snail habitats outside the embankment negatively correlated with the distance from the endemic villages to the Yangtze River (r = −0.094, P < 0.01; r = −0.225, P < 0.01; r = −0.177, P < 0.01). Conclusion The clustering areas of snail habitats along the Yangtze River Basin, notably the villages near the Yangtze River are key regions for snail monitoring and control in Hubei Province.

[Preparation and Molluscicidal Effect of Chlorosalicylicamide Sustained-release Granules].

Objective: To prepare the 5% and 10% chlorosalicylicamide（quinoid-2', 5-dichloro-4'-nitrosalicylanilide from niclosamide） sustained-release granules （LDS-SRG） and evaluate their molluscicidal effect. Methods: The 5% and 10% LDS-SRG were prepared with screened carriers, surfactants, adhesives, defoamers and lubricants. Their bulk density, water content, repose angle, critical relative humidity, thermal stability and release rate were determined. Spraying method was used to test the molluscicidal effect of LDS-SRG at 1.6 g/m2. Meanwhile, 50% wettable powder of niclosamide ethanolamine salt (WPN) was applied as the positive control at 1.0 g/m2, and dechlorinated water was used as the blank control. The mortality of snails was calculated on days 3, 7 and 14 after administration. Results: The 5% and 10% LDS-SRG were red brown in color, showed good fluidity, and had bulk density of 0.655 g/ml and 0.594 g/ml, moisture content of 1.15% and 1.28%, repose angle of 39.8° and 39.7°, and critical relative humidity of 64.98% and 61.63%, respectively. Moreover, both showed good thermal stability. The release curve was stable for both 5% and 10% LDS-SRG during day 1 to day 9, and faster release for 5% LDS-SRG than for 10% LDS-SRG. The burst release occurred on days 10 and 15, and the steady release occurred from days 14 and 20 for 5% and 10% LDS-SRG respectively. The snail mortality on day 7 after 5% LDS-SRG 1.6 g/m2 administration and on day 14 after 10% LDS-SRG 1.6 g/m2 administration was both higher than 95%, and higher than that of the 50% WPN 1.0 g/m2 control (P<0.05). Conclusion: The 5% and 10% LDS-SRG show sustained-release potential and satisfactory molluscicidal effect by spraying, reaching the evaluation standard for molluscicidal agents.

[The Molluscicidal Effect of Chlorosalicylicamide Sustained-release Granules on Oncomelania hupensis].

Objective: To evaluate the molluscicidal effect of the chlorosalicylicamide sustained-release granules (LDS-SRG) on Oncomelania hupensis. Methods: Seven effective concentrations or dosages of LDS-SRG, 0.1, 0.2, 0.4, 0.8, 1.6, 3.2 and 6.4 mg/L （for immersion test） or g/m2（for spraying test）, were prepared from the original 5% and 10% concentrations or dosages in the laboratory. In the immersion test, each concentration of LDS-SRG was incubated with 3 packs of snails（30 snails in each pack）, and each pack was taken for snail counting at 24, 48 and 72 h respectively. In the spraying test, each dosage of LDS-SRG was applied to 200 snails, and the snail mortality was calculated in 50 randmoly collected snails on days 3 and 7, and in the whole on day 14 after administration. In the field immersion test, LDS-SRG at concentrations of 0.4, 0.8 and 1.6 g/m3 was incubated with 6 packs of snails （30 snails in each pack）, and each 2 packs were taken at 24, 48, and 72 h to calculate the snail mortality. In the field spraying test, 0.8, 1.6 and 3.2 g/m2 LDS-SRG was sprayed in 3 snail-positive ditches （～100 m2）, and 10 boxes of snails were selected in each ditch on days 3, 7 and 14 to calculate the snail mortality. The 50% wettable powder of niclosamide ethanolamine salt （WPN） with effective concentrations or dosages of 1.0 mg/L （or g/m2 and g/m3） was used as the positive control. Fresh water served as the blank control. Results: In the labratory immersion test using the original concentration of 5%, both 0.1-6.4 mg/L LDS-SRG for 72 h and 1.6-6.4 mg/L LDS-SRG for 48 h caused 100% mortality; and the concentration lethal to 50% （LC50） at 24, 48 and 72 h was 0.70, 0.01 and 0.01 mg/L respectively. When using the original concentration of 10%, both 0.1-6.4 mg/L LDS-SRG for 72 h and 0.2-6.4 mg/L LDS-SRG for 48 h caused 100% mortality; and the LC50 at 24, 48 and 72 h was 0.15, 0.01 and 0.01 mg/L respectively. The labratory spraying test showed that 7-day administration of 1.6 and 6.4 g/m2 LDS-SRG as well as 14-day administration of 3.2 and 6.4 g/m2 LDS-SRG prepared from 5% dosage, resulted in a snail mortality>95%, with the LD50 on days 3, 7 and 14 being 0.06, 0.16, and 0.18 g/m2; 14-day administration of 1.6 g/m2 LDS-SRG as well as 7-day administration of 6.4 g/m2 LDS-SRG prepared from 10% dosage, resulted in a snail mortality>95%, with the LD50 on days 3, 7 and 14 being 3.29, 0.75, and 0.16 g/m2. The mortality by various dosages of LDS-SRG prepared from 5% dosage was significantly higher than that of the control group (P<0.05). In the field immersion test, the snail mortality by 1.6 g/m3 LDS-SRG prepared from 5% and 10% concentrations for 72 h was 96.43% and 98.21% respectively (P>0.05 versus the control group). In the field spraying test, the snail mortality by 3.2 g/m2 LDS-SRG prepared from 5% dosage for 3, 7 and 14 days was 93.99%, 91.18% and 86.48% respectively, and that from 10% dosage was 94.95%, 93.50% and 85.43%, all significantly higher than that of the control group （82.83%, 72.38% and 48.38%）（P<0.05）; the snail mortality by 0.8 g/m2 LDS-SRG prepared from 5% dosage for 14 days（66.51%） and that by 1.6 g/m2 LDS-SRG prepared from 5% dosage for 3 days（84.61%） were both significantly higher than that by 10% LDS-SRG（20.13% and 43.06%） （P<0.05）. Conclusion: The 5% and 10% LDS-SRG used separately in the immersion test and the spraying test both meet the requirements of the national standard of Efficacy Test Methods and Evaluation of Molluscicide for Pesticide Registration.

[Spatiotemporal pattern of Oncomelania snails at village level in Hubei Province].

OBJECTIVE: To study the spatiotemporal distribution of Oncomelania hupensis snails in different areal-types at a village level in Hubei Province, so as to provide the basis for formulating the strategies and measures of snail control. METHODS: The snail data of 30 schistosomiasis epidemic counties at a village scale in Hubei Province from 2007 to 2012 were collected and combined with the geographic information of each village to construct the spatial database of snails. The snail area and its change trend of different areal-types were illustrated; the multilevel model of snail distribution was established. RESULTS: The snail area of each village from 2007 to 2012 was correlated (Intra-class correlation coefficient, ICC = 95.7%). Both the baseline and the rate of change of snail area were significantly different (σ(2)(u0) = 4,766.53, σ(2)(u1)= 20.96, both P < 0.01). The rate of change of snail area was higher if the baseline of snail area was higher (σ(2)(u01) =126.78, P < 0.01). The snail areas of villages were increased slowly by year (year = 0.64,P < 0.01). The average snail areas and growth of snail areas of villages in the marshland and lake region were largest (type= -29.84, P < 0.01; year*type = -0.52, P < 0.01). CONCLUSIONS: The snail area is significantly different among both villages and areal-types. This study spatially visualizes the snail data of 30 schistosomiasis epidemic counties in Hubei Province and establishes the multilevel model, providing the basis of snail control in different areal-types.

[Acute toxicity of LDS, a molluscicide, to non-target organisms].

OBJECTIVE: To evaluate the acute toxicity of 10% LDS, a new molluscicide, to non-target organisms. METHODS: Based on "Chemical pesticide environmental safety test evaluation standard", an acute toxicity test was carried out with Coturnix coturnix japonica (quail), Apis mellifera L (bee), Bombyx mori (silkworm), and Brachydonio rerio (zebra fish) , and the skin stimulus test was also performed with guinea pig. RESULTS: The quails had no toxic symptoms while the maximum poisoning concentration of LDS was 200 mg/kg (no toxicity). LC50 of bees was 2.68 x 10³ mg/L (low toxicity). After 96 hours, no silkworms died in each group of different concentrations of LDS while the most concentration was 6.00 x 10² mg/kg, but there were some toxic symptoms such as inappetence and inactive in the high concentration group as compared to the blank control group (low toxic). LC50 (96 h) of zebra fish was 6.16 mg/L (medium toxicity). CONCLUSIONS: LDS has no toxicity to Coturnix coturnix japonica, low toxicity to Apis mellifera L and Bombyx mori, and medium toxicity to Brachydonio rerio. Compared with niclosamide ethanolamine salt, the toxicity to the fish is lower, and therefore, it is more suitable for the field application.

[Evaluation on molluscicidal effect of chlorosalicylicamide on Oncomelania hupensis in schistosomiaisis endemic areas of eight provinces in China].

OBJECTIVE: To evaluate the effects of a novel molluscicide, the salt quinoid-2', 5-dichloro-4'-nitrosalicylanilide from niclosamide (LDS), with 10% wettable powder, in main schistosomiasis epidemic areas of China, including Hunan, Jiangxi, Hubei, Anhui, Jiangsu, Sichuan, Yunnan and Zhejiang Province. METHODS: In the immersion test, 6 effective concentrations of 10% LDS were tested respectively: 0.1, 0.2, 0.4, 0.6, 0.8, 1.0 g/m3 in the field; at the same time, 50% wettable powder of niclosamide ethanolamine salt (WPN) with effective concentrations of 1.0 g/m was used as the molluscicide control, and the fresh water as the blank control, then the mortality rates of 0. hupensis snails were recorded at 24 h, 48 h and 72 h after the immersion. In the spraying test and powder-spraying test, 5 effective dosages of 10% LDS were tested respectively: 0.2, 0.4, 0.6, 0.8, 1.0 g/m2, while 50% WPN 1.0 g/m2 was used as the molluscicide control, and the fresh water as the blank control in the field for 1 d, 3 d and 7 d, then the mortality rates of O. hupensis snails were recorded at 1 d, 3 d and 7 d after the spraying and powder-spraying. RESULTS: The snail mortality rates of LDS using the immersion test for 72 h were more than 95% in the field of eight provinces (0.1 g/m in Sichuan, Jiangxi, Jiangsu and Zhejiang provinces, 0.2 g/m3 in Yunnan, Hunan and Hubei provinces, and 0.4 g/min Anhui Province); the snail mortality rates of LDS using the spraying test for 7 d were more than 85% (0.2 g/m2 in Hunan, Hubei, Jiangxi and Zhejiang provinces, 0.4 g/m2 in Sichuan and Anhui provinces, 0.6 g/m2 in Yunnan and Jiangsu provinces). The snail mortality rates of LDS the powder-spraying test for 7 d were more than 85% (0.6 g/m2 in Yunnan, Sichuan, Hubei, Jiangxi, Anhui, Jiangsu and Zhejiang provinces). According to the standards of "Efficacy test methods and evaluation of molluscicide for pesticide registration (NY/T 1617-2008)", LDS is a qualified molluscicide. CONCLUSIONS: LDS has good molluscicidal effects through the immersion, spraying and powder-spraying test in the fields. It is suitable for a variety of environments to control O. hupensis snails of schistosomiasis endemic areas in China. The recommended dosages of LDS are 0.1-0.2 g/m3 by the immersion method, 0.2-0.4 g/m2 by the spraying method, and 0.4-0.6 g/m2 by the powder-spraying method in the fields.

[Clinical study of delivery method in modified vaginal hysterectomy for large uterus].

OBJECTIVE: To prospectively explore the techniques, feasibility and safety of modified vaginal hysterectomy for large uterus. METHODS: A total of 158 patients undergoing hysterectomy at Beijing Hospital from January 2008 to December 2010 were divided into three groups: 12-16 gestational weeks large uterus for vaginal hysterectomy (n = 65, group 1), 12-16 gestational weeks uterus for abdominal hysterectomy (n = 47, group 2) and <10 gestational weeks uterus for vaginal hysterectomy (n = 46, group 3). The pattern and techniques of delivery in group 1 was based on the location of fibroids/adenomyoma (in anterior wall, posterior wall, uterine horn or broad ligament, cervix) and the direction of overall shape maximum diameter (direction towards abdomen defined as long type while the direction towards lateral pelvic wall wide type). The completion and safety were observed intraoperatively. The outpatient follow-up period was 1 month. RESULTS: A total of 158 cases of hysterectomy were performed successfully. The locations of fibroids/adenomyoma included anterior wall (n = 17), posterior wall (n = 24), unilateral uterine horn (n = 6), broad ligament (n = 3) and cervix (n = 2). in group 1, and there were long (n = 6) and wide (n = 7) types. They were all successfully delivered through vagina through various techniques. No case was converted into laparotomy. The average largest size (judged by as large as number of gestational weeks) and weight of uterus was group 2 and followed by group 1. But the difference of size and weight between two groups was insignificant (P > 0.05). Sorted by mean operative duration, mean amount of bleeding and decrease of hemoglobin, the declining order was the group 2, group 1 and group 3. The amount of bleeding for group 1 was less than that for group 2 (P < 0.05). But it was more than group 3 (P > 0.05). According to postoperative hospitalization duration, flatus time and indwelling catheter time, no statistical differences existed between groups 1 and 3. But the values of group 1 were significantly better than those of group 2 (P < 0.01, <0.05, <0.01). CONCLUSION: Vaginal hysterectomy is a safe and effective option for removing enlarged uterus. This pattern of operation can reduce the postoperative hospitalization time, flatus time and indwelling catheter time.

[Discussion of indoor quality control method of MPAIA antibody test of Schistosoma japonicum].

OBJECTIVE: To explore the scientific and effective indoor quality control method to ensure the results of Magnetic Particle Antibody Immunoassay (MPAIA) antibody test of Schistosoma japonicum reliable. METHODS: The MPAIA antibody test indoor quality control work was performed with the combination of the crubbs method, Z-scores figure and Westgard multi-rules quality control method. RESULTS: The crubbs test entered the quality control condition state from the third times, after 20 times, the test switched to Z-scores conventional quality control, and the Westgard multi-rules quality control method could help analyze the type of errors. From the third to fortieth test, 186 samples were completed and the tests of 9 samples among 2 batches needed to be re-done because of the failure of quality control. The test results of other 177 samples were acceptable. CONCLUSION: The combination of the crubbs method, Z-scores figure and Westgard multi-rules quality control method can effectively accomplish the indoor quality control of MPAIA antibody test of Schistosoma japonicum.

[Vaginal repair operation for anterior pelvic organ prolapse in elderly women].

OBJECTIVE: To identify the safety and efficacy of individualized vaginal surgery for anterior pelvic organ prolapse (POP) in elderly women so as to provide a clinical basis for studies on improving life quality by treatment in elderly women. METHODS: The individuation group consisted of 90 patients with a diagnosis of anterior POP. All over 60 years old, they underwent individualized vaginal surgery. The safety and efficacy, POP quantitative examination POP-Q change, cure and recurrence rate and life quality scores on incontinence and pelvic floor distress and impact were assessed. The control group (n = 60) was composed of patients (> 60 yr old) with a diagnosis of anterior POP were performed with Kelly-Kennedy operation. Their safety, efficacy, cure and recurrence rates were compared. RESULTS: Individualized vaginal surgery in elderly women was both safe and effective. The post-therapeutic recovery time was shorter (P < 0.05), the cure rate higher and the recurrence rate lower (P < 0.05) than that of control group. The life quality after individualized surgery improved (P < 0.01). CONCLUSION: The individualized vaginal surgery is safe and effective for a correction of anterior POP in elderly women. The life quality improves after operation.

Treatment of platinum-resistant recurrent ovarian cancer using a "predictive molecule targeted routine chemotherapy" system.

BACKGROUND: Correct drug selection, the key to successful chemotherapy, is one of the most difficult clinical decisions for the treatment of platinum-resistant recurrent ovarian cancer worldwide. The exact procedures for choosing drugs are undefined, currently relying on clinical trials and personal experience, which often results in disappointing outcomes. Here, we propose a new drug selection method, the "predictive molecule targeted routine chemotherapy", to choose relatively sensitive routine drugs and avoid relatively resistant routine drugs based on the specific predictive molecule expression of the individual tumor tissue. METHODS: From January 2004 to June 2008, 26 cases of platinum-resistant recurrent ovarian cancer were prospectively recruited. Their routine chemotherapy drug choice was based on the expression of 6 predictive molecules (including p53) as determined by immunohistochemistry (the predictive molecule targeted routine chemotherapy group). A further 18 cases of platinum-resistant recurrent ovarian cancer were treated by experience and formed the control group. The response rate and the overall survival were compared between the two groups. RESULTS: The response rate to second-line chemotherapy was 28% in the control group and 77% in the predictive molecule targeted routine chemotherapy group (P = 0.002). The response rate to third-line chemotherapy was 14% in the control group and 33% in the predictive molecule targeted routine chemotherapy group (P = 0.268). The median overall survival of the predictive molecule targeted routine chemotherapy group (88 weeks) was significantly longer than the median overall survival of the control group (56 weeks) (P = 0.0315). CONCLUSION: The predictive molecule targeted routine chemotherapy is a new effective protocol for choosing drugs when treating platinum-resistant recurrent ovarian cancer.

[The predictive factors for the response to platinum/paclitaxel based first-line adjuvant chemotherapy in advanced ovarian cancer].

OBJECTIVE: To investigate the predictive factors for the response to platinum/paclitaxel based first-line adjuvant chemotherapy in advanced ovarian cancer. METHODS: Forty-two patients with advanced ovarian cancer underwent complete resection plus platinum/paclitaxel as first-line adjuvant chemotherapy. The clinical outcomes were observed. Immunohistochemistry was used to detect the expression of p53, a tumor suppressor protein, and P-glycoprotein (Pgp), a multi-drug resistance associated gene product, in the specimens resected from operation. Retrospectively analysis of 42 cases r patients with. To calculate the complete response (CR) rate and early recurrence (ER) rate and to observe. The relationship between the parameters about clinical outcomes and some clinico-pathological variables, such as age, pathological type, differentiation degree, residual tumor, and molecular markers p53 and Pgp, was analyzed. RESULTS: Twenty-four patients (57%) showed CR and 7 (13%) showed ER. The CR rate of the p53 positive patients was 74%, higher than that of the p53 negative patients (44%, P = 0.065). The ER rate of the patients with residual tumor less than 2 cm was 4%, significantly lower than those with residual tumor > or = 2 cm (P = 0.018). Logistic regression analysis indicated that Pgp positivity and residual tumor > or = 2 cm were independent risk factors of ER. CONCLUSION: Residual tumor, p53, and Pgp expression are predictive factors for the response to platinum/paclitaxel first-line adjuvant chemotherapy in advanced ovarian cancer. The p53 positive patients are more sensitive to this protocol, and the Pgp positive patients and the patients with residual tumor > or = 2 cm are more resistant to this protocol.

[Evaluation on schistosomiasis control effect of the intervention measures adapted to the ecological environment changes in Jiang Han Plain due to establishment of the Three Gorges dam].

OBJECTIVE: To evaluate the effect of the intervention measures for schistosomiasis control adapted to the ecological environment changes in Jiang Han plain caused by the establishment of the Three Gorges Dam. METHODS: Four villages in Qianjiang City were selected to implement paddy-upland rotation, crawfish-paddy alternation, water control and soil improvement, and adjusting agricultural structure to rebuild the waterlogging low yielding land and to change the snail habitat environment respectively. The snail habitat area, mean density of living snails and prevalence of schistosomiasis in human and cattle were compared with those of the control villages. Miracidia hatching methods were used to examine the prevalence in human and cattle. RESULTS: In the four experimental villages, the snail-ridden area decreased by 100%, 51.35%, 62.16% and 87.88% respectively; mean density of living snails decreased by 100%, 69.41%, 52.30% and 75.77%, with a t value of 9.37, 4.91, 2.31 and 9.16, I'<0.01. Human prevalence of schistosomiasis in 2005 in village with crawfish-paddy alteration decreased significantly than control (chi2=39.84, I'<0.01); decreased by 73.10% in village with water control and soil improvement in 1990 than in 1987 (chi2=236.10, P<0.01). CONCLUSION: Implementation of the four intervention measures reaches a remarkable benefit in reforming snail habitat and protecting environment, which can be recommended to the inner embankment type endemic regions.

[Study on molluscicidal effect of chlorosalicylicamide].

OBJECTIVE: To observe the molluscicidal effect of chlorosalicylicamide on Oncomelania hupensis and toxicity on fishes. METHODS: Different concentrations of chlorosalicylicamide were prepared, and immersion and spraying methods were used to test its molluscicidal effect and toxicity to fishes. Niclosamide ethanolamine salt was used as control. RESULTS: Under water temperature of 28 C with the dose of chlorosalicylicamide at 0.25 mg/L and 0.4 mg/L, the mortality rate of snails by immersion was 97.8% and 100% respectively after 48 h, and the LC50 was 0.0674 mg/L. While for niclosamide at the same doses, the mortality rate of snails was 22.2% and 66.7% respectively, and the LC50 was 0.397 6 mg/L. With the concentration of 0.4 mg/L for 72 h, the fish death rate in chlorosalicylicamide and niclosamide was 50.0% and 100% respectively. CONCLUSION: Chlorosalicylicamide shows a molluscicidal effect on Oncomelania snails and a lower toxicity to fishes than that of niclosamide.

Feasibility and safety of vaginal myomectomy: analysis of 90 cases.

BACKGROUND: Vaginal myomectomy was firstly reported in 1994, however, it is a relatively new technique in China. The feasibility and safety of the procedure is still controversial in this country. The aim of this study was to analyze the outcomes of vaginal myomectomy in 90 patients and to investigate the feasibility and safety of the surgery. METHODS: From June 2001 to June 2004, 90 patients with uterine leiomyoma were treated with vaginal myomectomy in our hospital (vaginal group). The indications, operative performance, postoperative complications, and recovery of the patients were analyzed and compared with those of 93 patients with uterine leiomyoma treated by laparotomic myomectomy from January 2000 to January 2001 (laparotomy group). The Student's t test was used to compare the continuous variables between the two groups, and the chi-square test was used to compare the categorical variables. The vaginal and laparotomy groups were followed up for 10 - 34 months (median, 21) and 15 - 24 months (median, 30), respectively. RESULTS: Vaginal myomectomy was performed successfully in 87 of the 90 patients (96.7%). In the other 3 patients, the procedure failed and laparotomy was carried out. In both groups, the uterus was enlarged to 8 - 16 weeks gestational size (median, 10 gestational weeks). The number of resected tumors was 1 - 12 (median, 2) in the vaginal group and 1 - 15 (median, 4) in the laparotomy group, respectively (P > 0.05). The mean operating time, intraoperative blood loss, and postoperative hospital stay were (52 +/- 21) minutes, (230 +/- 44) ml, and (7.0 +/- 1.2) days in the vaginal group, and (65 +/- 32) minutes, (200 +/- 56) ml, and (7.0 +/- 1.5) days in the laparotomy group (P > 0.05). The mean top postoperative temperature was (38.4 +/- 1.1) degrees C and (37.8 +/- 0.6) degrees C in the two groups respectively (P < 0.05). Both groups had one recurrent case during the follow-up (P > 0.05). CONCLUSIONS: Vaginal myomectomy is feasible and safe in treating uterine leiomyoma. To some extent, it is superior to laparotomic myomectomy by avoiding severe trauma during the surgery.

[Purification of the effective component from Solanum xanthocarpum and its effect against Oncomelania snails].

OBJECTIVE: To extract and purify the active component from Solanum for Oncomelania snail control, evaluate its effect against the snails and determine its chemical structure. METHODS: Pedicel and seed were moved and the remaining part of the Solanum xanthocarpum fruit was torrefied and ground into powder. The powder was soaked into 95% ethanol and extracted. The residue was treated by ethyl acetate. 7 components were separated by methods of thin layer chromatography (TLC) and column chromatography (CCL). 4 main components were observed for the effect of snail-killing by immersion method. An alkaloid with Rf = 0. 58, named as component A, was confirmed as one of the effective components for Oncomelania snail control. The component A was further purified and received Al and A2 by proper elusion, and their effect was re-tested. The molecular weight and chemical structure of A2 were determined by MS, NMR and IR respectively. RESULTS: The death rate of Oncomelania snails was 94.2% when the concentration of component A was 2.50 mg/L1(28 C ). The flow liquid system (ethyl acetate: chloroform: methanol 11:11:35) applied was the best reagent for separating component A. The death rate of Oncomelania snails in solution of A2 (0.2 mg/L) was 100% (28 degrees C). The molecular weight of A2 was 867 with an mp 298-305 C. CONCLUSION: The effective agent (A2),one of the active components from the fruit of Solanum xanthocar pum, is alpha-solamargine which shows an excellent effect in killing Oncomelania snails.

[Study on the risk factors of schistosomiasis transmission and control strategy in the Three Gorges Reservoir Areas].

OBJECTIVE: To understand the risk factors of schistosomiasis transmission in the Three Gorges Reservoir Area (TGRA) and to provide evidence for the development of control strategy. METHODS: Approaches including epidemiology, immunology and field survey were applied to investigate the potential risk factors which would involve the importation of infectious resources live mobile and migrant population, and livestock in the reservoir area. Meanwhile, observation on survival and reproductive status of snail under simulation habitats was also carried out, using ecological methods on snails. Strategy in preventing the spread of snail as infectious resources was also provided. RESULTS: 175 mobile people from schistosomaisis endemic area of were tested and one person showed immunology tests positive with indirect hemagglutination test (IHA) and circumoral precipitin test (COPT), with a positive rate of 0.57%. Through the two-year period under observation, data showed that the snails with ribbon/smooth shells could survive and reproduce under habitats of simulation. CONCLUSIONS: Once the infectious resource of schistosomiasis was introduced into the TGRA, the area became a new schistosomiasis epidemic area in TGRA which called for countermeasures to be taken.