Utility of Droplet Digital PCR Assay for Quantitative Detection of Norovirus in Shellfish, from Production to Consumption in Guangxi, China.

OBJECTIVE: Shellfish are recognized as important vehicles of norovirus-associated gastroenteritis. The present study aimed to monitor norovirus contamination in oysters along the farm-to-fork continuum in Guangxi, a major oyster production area in Southwestern China. METHODS: Oyster samples were collected monthly from farms, markets, and restaurants, from January to December 2016. Norovirus was detected and quantified by one-step reverse transcription-droplet digital polymerase chain reaction (RT-ddPCR). RESULTS: A total of 480 oyster samples were collected and tested for norovirus genogroups I and II. Norovirus was detected in 20.7% of samples, with genogroup II predominating. No significant difference was observed in norovirus prevalence among different sampling sites. The norovirus levels varied widely, with a geometric mean of 19,300 copies/g in digestive glands. Both norovirus prevalence and viral loads showed obvious seasonality, with a strong winter bias. CONCLUSION: This study provides a systematic analysis of norovirus contamination 'from the farm to the fork' in Guangxi. RT-ddPCR can be a useful tool for detection and quantification of low amounts of norovirus in the presence of inhibitors found particularly in foodstuffs. This approach will contribute to the development of strategies for controlling and reducing the risk of human illness resulting from shellfish consumption.

Human umbilical cord mesenchymal stem cell transplantation restores hematopoiesis in acute radiation disease.

OBJECTIVE: Nuclear technology has been widely used in military and civilian fields, and radiotherapy is an effective and common form of treatment for cancer. However, acute radiation disease caused by high doses of radiation is a serious complication. The aim of this study was to investigate the chance of mitigating radiation-triggered hematopoiesis failure using human umbilical cord mesenchymal stem cell (HUCMSC) transplantation. METHODS: Umbilical cords were obtained from three full-term female neonatus through cesarean section at Xinqiao Hospital. Bone marrow mesenchymal stem cells (BMSCs) were cultivated as depicted before. Briefly, monocytes were collected from bone marrow blood by means of density separation columns. An acute radiation disease mouse model was established to compare the restoration effect of HUCMSCs and BMSCs transplanted via the tail vein. The hematopoietic stem cell transplantation (HSCT) mouse model was obtained through bone marrow cell transplantation (BMCT) from C57BL/6 mice (H-2b, donor) to female CB6F1 mice (H-2b×d, recipient) after irradiation. The mice were divided into five groups, including control (saline), irradiated (radiation), bone marrow (HSCT, transplanted 1×106 BM cells), HUCMSC (transplanted a mixture of 1×106 HUCMSCs and 1×106 BM cells), and BMSC group (transplanted a mixture of 1×106 BMSCs and 1×106 BM cells). The blood condition results were used to test the radiation-induced inflammatory reaction, and bone marrow pathological staining (H&E) was used to determine the radiation-induced bone marrow hematopoiesis failure. RESULTS: After radiation, HUCMSC transplantation significantly improved the survival rate. By analyzing the blood condition test, colony formation, and bone marrow pathology, it was found that the HUCMSC group demonstrated significant functional improvements in terms of the recovery from hematopoiesis failure and reduction of inflammatory reaction. CONCLUSIONS: HUCMSCs have more advantages over BMSCs in restoring and promoting the recovery of radiation-induced hematopoietic damage, thus having a new therapeutic potential for patients with acute radiation disease.

Optimization of food deprivation and sucrose preference test in SD rat model undergoing chronic unpredictable mild stress.

BACKGROUND: The chronic unpredictable mild stress (CUMS) model has long been considered the best model for exploring the pathophysiological mechanisms underlying depression. However, there are no widely recognised standards for strategies for modeling and for behavioral testing. The present study aimed to optimize the protocols for food deprivation and the sucrose preference test (SPT) for the CUMS model. METHODS: We first evaluated the effects of different long periods of food deprivation on the body weight of Sprague Dawley (SD) rats by testing food deprivation for 24 hours (8:00-8:00+), food deprivation for 12 hours during the daytime (8:00-20:00) and food deprivation for 12 hours at night (20:00-8:00+). Next, we established a SD rat CUMS model with 15 different stimulations, and used body weight measurement, SPT, forced swim test (FST), open field test (OFT) and Morris water maze (MWM) test to verify the success of the modeling. In the SPT, consumption of sucrose and pure water within 1 and 12 hours was measured. RESULTS: Twelve hours of food deprivation during the daytime (8:00-20:00) had no effect on body weight, while 12 hours of food deprivation at night (20:00-8:00+) and 24 hours of food deprivation (8:00-8:00+) significantly reduced the mean body weight of the SD rats. When SPT was used to verify the successful establishment of the CUMS rat model, sucrose consumption measured within 12 hours was less variable than that measured within 1 hour. CONCLUSIONS: Twelve hours of food deprivation in the daytime (8:00-20:00) may be considered a mild stimulus for the establishment of a CUMS rat model. Measuring sucrose consumption over 12 hours is recommended for SPT.

[Effect of sFRP2 on the biological behavior of HepG2 cells].

OBJECTIVE: To investigate the effect of sFRP2 on the biological behavior of human hepatoma carcinoma HepG2 cells. METHODS: HepG2 cells were infected with recombinant adenovirus containing mouse sFRP2 gene, and then the proliferation, cell cycle distribution, expression of tumor metastasis related factors (CD44, CD82/KAI1, EMMPRIN) and beta-catenin protein, and migration ability of the cells were detected by MTT, FCM, immunohistochemistry, Western blot and Transwell inserts, respectively. RESULTS: sFRP2 protein inhibited the proliferation of HepG2 cells, and increased the percentage of G0/G1 period cells. Expression of CD44 and CD82/KAI1 proteins, which could inhibit invasion and metastasis of tumor cells, was upregulated. However, EMMPRIN protein, which could promote the above properties of tumor cells decreased in HepG2 cells infected with the recombinant adenovirus containing mouse sFRP-2 gene. Western blot demonstrated that beta-catenin was expressed in HepG2 cells and there was no significant difference between the treated and the control groups. Transwell insert test showed sFRP2 protein decreased the migration ability of HepG2 cells. CONCLUSION: The recombinant adenovirus containing mouse sFRP-2 gene could infect HepG2 cells. sFRP2 protein could significantly reduce the capability of proliferation, invasion and metastasis of HepG2 cells.

A mass vaccination campaign targeting adults and children to prevent typhoid fever in Hechi; expanding the use of Vi polysaccharide vaccine in southeast China: a cluster-randomized trial.

BACKGROUND: One of the goals of this study was to learn the coverage, safety and logistics of a mass vaccination campaign against typhoid fever in children and adults using locally produced typhoid Vi polysaccharide (PS) and group A meningococcal PS vaccines in southern China. METHODS: The vaccination campaign targeted 118,588 persons in Hechi, Guangxi Province, aged between 5 to 60 years, in 2003. The study area was divided into 107 geographic clusters, which were randomly allocated to receive one of the single-dose parenteral vaccines. All aspects regarding vaccination logistics, feasibility and safety were documented and systematically recorded. Results of the logistics, feasibility and safety are reported. RESULTS: The campaign lasted 5 weeks and the overall vaccination coverage was 78%. On average, the 30 vaccine teams gave immunizations on 23 days. Vaccine rates were higher in those aged < or = 15 years (90%) than in adolescents and young adults (70%). Planned mop-up activities increased the coverage by 17%. The overall vaccine wastage was 11%. The cold chain was maintained and documented. 66 individuals reported of adverse events out of all vaccinees, where fever (21%), malaise (19%) and local redness (19%) were the major symptoms; no life-threatening event occurred. Three needle-sharp events were reported. CONCLUSION: The mass immunization proved feasible and safe, and vaccine coverage was high. Emphasis should be placed on: injection safety measures, community involvement and incorporation of mop-up strategies into any vaccination campaign. School-based and all-age Vi mass immunizations programs are potentially important public health strategies for prevention of typhoid fever in high-risk populations in southern China.

[Norovrius genotype I.8 being detected from sporadic cases of acute gastroenteritis in Nanning municipal].

OBJECTIVE: To study the genic characteristic of Norovrius genotype I.8 from sporadic gastroenteritis of a hospital in Nanning Municipal. METHODS: Specimens of diarrhea patients from a hospital in Nanning Municipal between January 2007 and December 2008 were collected and detected for Noroviral genogroup Iribonucleic acid (RNA) by real-time reverse transcription-polymerase chain reaction(real-time RT-PCR). All positive specimens were subjected for sequencing analysis and constructed phylogenetic tree. RESULTS: Norovirus genogroup I RNA were detected in 3 of 696 stool specimens. The homology between one of the four strains (NN07230) and reference strain of G I.8 (WUG I/00/JP) was 94.5%; and the homology between the NN07230 strain and strains circulating during 2006-2007 in Japan and Korea ranged from 96.7% to 98.5%. And they formed one cluster in the phylogenetic tree. CONCLUSION: The research showed that genotype I.8 infection exists in sporadic gastroenteritis in Nanning City.

[Norovirus infection in adults with sporadic gastroenteritis during 2007-2008 in Nanning Municipal].

OBJECTIVE: To investigate the epidemiological characteristic and genotype distribution of norovirus infection among adult patients with sporadic gastroenteritis in Nanning Municipal. METHODS: The epidemiological data of adult diarrhea patients in outpatient clinics of a hospital in Nanning City between January 2007 and December 2008 were analyzed. A total of 696 fecal specimens were collected from the patients and were screened for the presence of norovirus RNA by real-time reverse transcription-polymerase chain reaction. Some positive specimens were selected randomly and subjected for sequencing and phylogenetic analysis to identify genotypes. RESULTS: The sporadic norovirus infection in adults occurred preferentially during the cold season, and there was no statistical difference in the detection rate between age groups. 183 (26.30%) of 696 specimens were positive for norovirus RNA. Among them, 180 (98.36%) belonged to genogroup II (G II) and the other 3 (1.64%) belonged to genogroup I (G I). The sequence analysis showed that all 10 G II strains selected randomly belonged to genotype G II4, while 3 GI strains were classified into three different genotypes: G I2, G I4 and G I8. CONCLUSION: The study showed that norovirus was an important etiologic agent of sporadic gastroenteritis among adults in Nanning City. Genotype G II4 was the predominant genotype, and genotype GI existed sporadically.

[Epidemiologic surveillance for bacterial meningitis in 140 000 children under 5 years of age in Nanning district, Guangxi province].

OBJECTIVE: To characterize the incidence, epidemiologic features, etiologic agents and sequelae of bacterial meningitis in children under 5 years of age in Nanning, Guangxi. METHODS: A population-based surveillance was conducted to evaluate children with signs and symptoms of meningitis. All hospitals, township health centers and village clinics in the surveillance area were structured to participate in the case referral and evaluation. Cerebrospinal fluid (CSF) and blood specimens were obtained and processed using standardized microbiologic methods. RESULTS: During the 26-month surveillance period, among the children under 5 years old, a total of 1272 cases who met the screening criteria of meningitis were studied. 265 of 1272 cases were identified as clinically diagnosed meningitis, with an incidence rate of 86.36 per 100 000 population. The annual incidence rate under the 38 cases of confirmed bacterial meningitis appeared to be 12.38/100 000. Staphylococcus species accounted for the largest proportion of laboratory-confirmed bacterial meningitis, followed by E. coli and S. pneumoniae. The highest attack rate occurred in neonates < 1 month, followed by children aged 1 - 12 months in the confirmed patients. Meningitis caused by Sp and Hi mainly occurred in children aged 1 - 12 months. All cases of meningitis due to Hi and Sp were children aged 1 - 24 months. 13.16% and 0.00% of the cases survived with complications and sequelae, and the case-fatality rate was 18.42%. 40 bacterial isolates were identified from 1193 blood cultures and 23 from 1211 cerebrospinal fluid samples, but no Neisseria meningitidis was found. CONCLUSION: Meningitis due to Hi was first confirmed in Guangxi with the incidence of 0.98 per 100 000 population. The annual incidence rate of confirmed bacterial meningitis was 12.38 per 100 000, which was considered an important public health problem in children. Staphylococci was the predominant pathogen in confirmed bacterial meningitis.