[Current status and challenges for taeniasis and cysticercosis control in China]

In the WHO new road map for neglected tropical diseases 2021-2030, the disease-specific targets are classified into control, elimination as a public health problem, elimination and eradication, and taeniasis and cysticercosis are targeted for control. The overall prevalence of taeniasis and cysticercosis is low in China, and varies remarkably in regions and populations; however, there are many challenges for elimination of taeniasis and cysticercosis in China. Based on previous taeniasis and cysticercosis control programs, developing a sensitive taeniasis and cysticercosis surveillance-response system, updating criteria for diagnosis of taeniasis and cysticercosis, proposing a national guideline for treatment of taeniasis and cysticercosis, and strengthening interdisciplinary and intersectoral communications and collaborations are urgently needed under the One Health concept.

[Prevalence of soil - borne nematode infections among residents living in urban/town areas of China in 2015]

OBJECTIVE

To understand the prevalence of soil-borne nematode infections among residents living in urban/town areas of China, so as to provide insights into the control and elimination of soil-borne nematodiasis.

METHODS

A total of 5 epidemic areas were classified in China according to the prevalence of human Clonorchis sinensis infections captured from the 2014-2015 national survey on major human parasitic diseases in China, and the total sample size was estimated according to the binomial distribution and Poisson's distribution. Then, the total sample size was allocated proportionally to each province (autonomous region, municipality) of China based on the percentage of residents living in urban and town areas, and the number of survey sites in each province (autonomous region, municipality) was proportionally assigned according to the percentages of residents living in urban and town areas. Then, stratified sampling was performed at county, township and community levels according to the number of sampling sites in each province (autonomous region, municipality), and the survey site (community) was defined as the smallest sampling unit. All permanent residents in the survey sites were selected as the study subjects, and their stool samples were collected for identification and counting of parasite egg using a Kato-Katz technique. The prevalence and intensity of each parasite species were calculated.

RESULTS

From 2014 to 2015, among the 133 231 residents detected in 31 provinces (autonomous regions, municipalities) of China, the overall prevalence of soil-borne nematode infections was 1.23% (1 636/133 231), and the prevalence rates of hookworm, Ascaris lumbricoides and Trichuris trichiura infections were 0.77% (1 032/133 231), 0.32% (426/133 231) and 0.17% (224/133 231), respectively. The highest prevalence of soil-borne nematode infections was seen in Jiangxi (4.03%, 82/2 034) and Chongqing (4.03%, 524/13 012), followed by in Hainan (3.47%, 72/2 075). The prevalence of soilborne nematode infections was 1.07% (662/62 139) in men and 1.37% (974/71 092) in women, and the greatest prevalence was found in residents at ages of 65 to 70 years (2.56%, 219/8 569). With regard to occupations and education levels, herdsmen (2.47%, 2/81) and illiterate residents (3.33%, 226/6 795) were found to have the highest prevalence of soil-borne nematode infections, respectively. In addition, mild infections were predominantly identified in hookworm-, A. lumbricoides- and T. trichiura-infected individuals (all > 90%).

CONCLUSIONS

The overall prevalence of soil-borne nematodiasis remains low in urban and town areas of China; however, human infections are widespread. According to the epidemiological features, health education combined with deworming are recommended to reduce the prevalence of soil-borne nematode infections among residents living in urban and town areas of China.

[National surveillance on Enterobius vermicularis infections among children at ages of 3 to 9 years in China from 2016 to 2018]

OBJECTIVE

To understand the epidemic status of Enterobius vermicularis infections among children aged 3 to 9 years in China, so as to provide scientific basis for the formulation of the prevention and control strategies for enterobiasis.

METHODS

The national surveillance of enterobiasis was performed in 736 national surveillance sites (counties) from 30 provinces (municipalities/autonomous regions) in China from 2016 to 2018. All surveillance sites were classified into parts according to the geographical directions, including the eastern, western, southern, northern and middle parts, and a township was randomly selected from each part. Then, an administrative village was randomly selected from the township, and 200 permanent residents at ages of over 3 years living in the administrative village were randomly selected using the cluster sampling method. A total of 1 000 residents were examined in each surveillance site. E. vermicularis infections were detected among children at ages of 3 to 9 years using the modified Kato-Katz technique and the adhesive cellophane-tape perianal swab method, and the prevalence of infections was calculated and compared.

RESULTS

The prevalence of E. vermicularis infections was 2.50%, 2.84% and 2.46% among children at ages of 3 to 9 years in the 736 surveillance sites from 30 provinces (municipalities/autonomous regions) in China from 2016 to 2018, and there was no gender-specific prevalence of E. vermicularis infections (P > 0.05). Enterobiasis was main prevalent in the southern and southwestern part of China (Jiangxi, Guangxi, Guangdong, Sichuan, Fujian, Chongqing and Hainan), with 5.00% prevalence and greater, and the highest prevalence was seen in Jiangxi and Guangxi for successive 3 years. In addition, the prevalence of E. vermicularis infections was higher in children with the Han ethnicity than in those with the minority ethnicity, and a high prevalence was found in children at ages of 4 to 7 years, and a low prevalence seen in children at ages of 3, 8 and 9 years.

CONCLUSIONS

The prevalences of E. vermicularis infections have not changed much among children at ages of 3 to 9 years in China from 2016 to 2018, and high prevalence is seen in southern and southwestern China, which should be given a high priority.

[Establishment of an evaluation system for the field assessment of the Kato-Katz technique in detection of soil-transmitted nematodiasis]

OBJECTIVE

To establish an evaluation system for the field assessment of the Kato-Katz technique in detecting soiltransmitted nematodes, so as to provide insights into the field application of the Kato-Katz technique.

METHODS

The initial evaluation indicators were determined through literature search, brainstorming and expert consultation. The evaluation indicatorswere improved and the weight of each indicator was decided through three rounds of expert consultation by using the Delphimethod. In addition, the expert authority coefficient and the coordination coefficient of each indicator were calculated at eachround of expert consultations.

RESULTS

The recovery rates of the questionnaire were 100.00%, 100.00% and 89.29% at the firstto the third round of the expert consultations, respectively, and the expert authority coefficients were all more than 0.85 at eachround. The final evaluation system included 4 first-level indicators and 15 second-level indicators. In the first-level indicators, "detecting effect" and "funds investment" had the mean weighted value of 4.53 and 4.49, which were relatively higher than that of"person-time investment" and "operability" (both 4.34). Among the second-level indicators under each first-level indicator, thefour most significant indicators included "ability of personnel in egg discrimination", "cooperation of village cadres and doctors","Person-time on testing" and "organizational start-up cost", with the mean weighted values of 4.74, 4.43, 4.39 and 4.17, respectively. The coordination coefficients were 0.39 to 0.65, 0.28 to 0.58 and 0.45 to 0.65 at the first to the third round of the expertconsultations, respectively, and there were significant differences in the coordination coefficients at all three rounds of the consultations (all P < 0.05).

CONCLUSIONS

An evaluation system for the field assessment of the Kato-Katz technique in detecting soiltransmitted nematodes is successfully established, among which "ability of personnel in egg discrimination" and "cooperation ofvillage cadres and doctors" have the greatest mean weighted values of the significance.

[Establishment and role of national clonorchiasis surveillance system in China]

Clonorchiasis is one key food-borne parasitic disease in China. Owing to several years'efforts and preparation, the national clonorchiasis surveillance system in China has been established preliminarily since 2016. In this article, the necessity to establish the national clonorchiasis surveillance system is explained. Then, the structure, content and corresponding methods of the surveillance system are briefly introduced. Key points in the surveillance are summarized and the development of surveillance in future is discussed. Furthermore, the contribution of clonorchiasis surveillance in China to the world is also analyzed.

WITHDRAWN: Expression analysis of Sca-1 and its significance in lung cancers

Ahead of Print article withdrawn by publisher. The purpose of the present study was to determine the expression of Sca-1, the stem cell marker, among various lung cancers and evaluate their utility. Immunohistochemistry was done in 151 surgically resected lung cancer specimens or biopsies, including 76 cases of adenocarcinoma, 50 cases of squamous cell carcinoma, 15 cases of small cell carcinoma, 6 cases of adenosquamous cell carcinoma and 4 cases of large cell carcinoma. The results showed that 88 (58.3%) cases were Sca-1 positive. Further analysis showed that in cases of adenocarcinoma, the rate of lymph node invasion and poor differentiation level of Sca-1(+) specimens were respectively higher than those of Sca-1(-) specimens. In cases with small cell carcinoma and squamous cell carcinoma, the rates of lymph node invasion of Sca-1(+) specimens were respectively higher than those of Sca-1(-) specimens. Survival analysis showed that for patients with adenocarcinoma and small cell carcinoma, the average survival time of Sca-1(+) patients was significantly shorter than that of Sca-1(-) patients. Further mutation analysis showed that EGFR mutation rates in Sca-1 (-) adenocarcinoma patients were significantly higher than those of Sca-1 (+) patients, while p53 and KRAS mutation rates in Sca-1 (-) adenocarcinoma and squamous cell carcinoma patients were respectively lower than those of Sca-1 (+) patients. Western blots analysis showed that expression of a Src family tyrosine kinase, Fyn, was positively related with Sca-1 expression levels. These results suggested that Sca-1 expression in some human lung cancers was related with malignancy phenotype and survival time. Keywords: Sca-1 expression, stem cancer cell, lung cancer, malignancy phenotype.

Human lung cancer cell line SPC-A1 contains cells with characteristics of cancer stem cells

Cancer stem cells (CSCs) play important roles in occurrence, development, recurrence and metastasis of cancer. Isolation and identification of CSCs have been performed from some cancer tissues or cells. In this paper, human lung adenocarcinoma stem cells were induced and isolated from SPC-A1 cells and their characteristics were determined. SPC-A1 cells were cultured in serum-free medium and epidermal growth factor and basic fibroblast growth factor were added into the medium to induce the formation of multicellular tumor spheroids. The results showed that floating multicellular tumor spheroids (named pulmospheres) were formed 5-10 d after the induction of SPC-A1 cells. Real-time PCR analysis showed that in the pulmospheres, the marker of bronchioalveolar stem cells, Clara cell secretary protein and the marker of AT2 cells, alveolar surfactant protein C were highly expressed. Furthermore, such embryonic stem cell markers as octamer-binding transcription factor 4 (OCT-4), Bmi-1, and thyroid transcription factor -1 (TTF-1) were also highly expressed. Some miRNAs as hsa-miR-126, hsa-miR-145, hsa-let-7g, hsa-let-7d, hsa-let-7c, hsa-let-7e and hsa-miR-98, which were lowly expressed in SPC-A1 cells, were not expressed in the pulmospheres. Cell cycle analysis showed that 94.29 % of the pulmosphere cells were in G1 stages. Further study showed that these cells possessed higher proliferation and invasion activity than SPC-A1 cells. Tumorigenicity activity experiments on BALB/c nude mice showed that 1 × 103 of the pulmosphere cells could form tumors with similar pathological features with lung adenocarcinoma. In conclusion, lung adenocarcinoma stem cells were enriched in the pulmosphere cells and were with high tumorigenicity.

Overexpression of Smad ubiquitin regulatory factor 2 suppresses transforming growth factor-β mediated liver fibrosis

OBJECTIVE

To determine the function of Smad ubiquitin regulatory factor 2 (Smurf2) on the development of liver fibrosis and cirrhosis.

METHODS

In vivo Smurf2 expression in fibrotic and cirrhotic rat and human liver tissues were measured using reverse transcription-polymerase chain reaction, Western blot (WB) and immunohistochemistry. In vitro Smurf2 levels were determined in LX-2 cell line with or without transforming growth factor (TGF)-β1 treatment; I, III, IV collagen and laminin levels were determined by ELISA. The recombinant plasmid pcDNA3.1-Smurf2 was transfected into LX-2 cells, and WB and ELISA were utilized to analyze the expression of TGF-β receptor type I (TβRI), Smad7, collagens and laminin with or without proteasome inhibitor MG-132. Coimmunoprecipitation was utilized to characterize the interactions among these factors and the ubiquitination levels. pcDNA3.1-Smad7 vector was transfected and subsequent examinations were conducted just as Smurf2.

RESULTS

Smurf2 levels were elevated in the early period of fibrotic rat liver and TGF-β1-treated LX-2 cells but were reduced in the cirrhotic livers. Smurf2 overexpression in LX-2 cells reduced TβRI and Smad7 levels, which was accompanied by decreased collagen and laminin levels. Coimmunoprecipitation demonstrated that Smurf2 interacted with TβRI and Smad7, which increased TβRI and Smad7 ubiquitin levels. Smad7 overexpression reduced the TβRI level and was accompanied by decreased collagen and laminin levels. MG-132 could antagonize these effects.

CONCLUSION

Smurf2 interacts with Smad7 to suppress TGF-β-mediated liver fibrosis through the ubiquitin-dependent degradation of TβRI during the early period of liver fibrosis.

A methodology of characterizing status and trend of land changes in oases: a case study of Sangong River watershed, Xinjiang, China

Land change is often studied with Markov models to develop a probability transition matrix. The existing methods dependent on such matrixes cannot effectively characterize some important aspects associated with land change such as status, direction, trend and regional variations. This study presents mathematical models to quantify these elements, defining unbalanced, quasi-balanced and balanced status, one- and two-way transitions and the rising or falling trends. Using these models and remote-sensing imageries, the landscape was studied for a case area, the oasis of Sangong River in Xinjiang, Northwest China where typical arid conditions prevail. Land expansion and contraction among various land types and for the entire oasis were analyzed for the periods of 1978-1987, 1978-1998 and 1987-1998. The changes were closely related to a strong economic growth after the land-reform campaign and adoption of the market economy in China in the 1980s to early 1990s, a process not strictly Markovian that requires stationarity and randomness. Information on land-change status and trend is important for a better understanding of the underlying driving processes but also for land-use planning and decision-making.

Abnormal expression of Smurf2 during the process of rat liver fibrosis

OBJECTIVE

Liver fibrosis is a prelude of liver cirrhosis. Currently the molecular mechanism of liver fibrosis is not clear. The purpose of this study is to screen the abnormally expressed genes of liver fibrosis and to illustrate the changes of Smurf2 expression in the process of liver fibrosis.

METHODS

A liver fibrosis model was established in rats by injection of tetrachlormethane (CCl(4)). A cDNA microarray analysis was performed on the liver at mid-stage of fibrosis. Thereafter, a semi-quantitative RT-PCR, Western blot analysis and immunohistochemistry test were performed for determining Smurf2, Smad2 and SnoN at week 1, 2, 4 and 8 of establishing the liver fibrosis model.

RESULTS

Smurf2, FGG, PTAFR, CYP2D6, among others, increased in the fibrosis liver and a semi-quantitative RT-PCR confirmed the reliability of the cDNA microarray analysis. Smurf2 in the liver fibrosis model group was at the same level as that of control group at week 1, but decreased at week 2 and 8 and increased at the week 4. Smad2 increased at week 2 and 8 but increased at week 4. However, Smad2 mRNA increased to the same level at week 4 as that at week 2 and 8. The decrease of Smad2 at week 4 may be due to the enhancement of ubiquitination and proteolytic degradation of Smad2 by the increase of Smurf2. SnoN decreased at week 4 and 8 because of the ubiquitination and degradation caused by Smurf2. The decrease of SnoN may explain the progress of liver fibrosis in spite of the decrease of Smad2 at week 4.

CONCLUSION

This study screened the abnormally expressed genes of liver fibrosis and illustrated the changes of Smurf2, Smad2 and SnoN during the process of liver fibrosis.

[On cleanliness of hands in diminution of Ascaris lumbricoides infection in children]

OBJECTIVE

To study the relationship between cleanliness of children's hands and diminution of Ascaris lumbricoides infection.

METHODS

Before the study all persons positive for ascaris eggs in the preliminary survey were treated with albendazole. Hand-washing habit before meal and after defecation was kept in children of experimental group, but not in the control group. Kato thick smear stool examination was done once every two months for one year to compare the new infection rates in children without ascaris infection in the two groups, and the reinfection rates in the cured negative cases were also compared between them in half a month after chemotherapy.

RESULTS

All the new infection rates as well as reinfection rates of each reexamination in the experimental group were significantly lower than that of the control group (P < 0.001). Reexamination one year later showed that the ascaris infection rate of the experimental group was 35.2%, reducing by 48.5% as compared with 68.3% before the operation of the project; while ascaris infection rate of the control group was 73.7%, increasing by 78.0% as compared with 41.4% before the operation of the project.

CONCLUSION

Washing hands with toilet soap to keep hands clean can significantly reduce ascaris infection rate.

Development of a K562 cell-based assay for screening anticancer agents

AIM

To develop a leukemia cell line K562-based assay for high-throughput screening.

METHODS

The screening was carried out on 96-well plates with monitoring cell proliferation by a combined 3-[4,5-dimethylthiazol-2-yl]-5-[3-carboxymethoxyphenyl]-2-[4-sulfophenyl]-2H-tetrazolium (MTS)/phenazine methosulfate (PMS) method. Conditions for evaluating effects on the proliferation of K562 cells by individual compounds on the 96-well plates were optimized.

RESULTS

A set of 800 small organic compounds was screened for anticancer activity by this cell-based assay, with consumption of each compound at 500 ng. Eleven compounds were identified with >80 % inhibitory activity at 5 mg/L, among which 9 compounds were confirmed by subsequent testing at multiple concentrations. The most potent compound showed an IC50 at 170 nmol/L, and there were total of 7 compounds showed IC50 less than 10 micromol/L.

CONCLUSION

The high-throughput method using K562 cell line is fast, economical, effective, and practical in identifying inhibitors as potential therapeutic agents for cancer.