[Investigation of a norovirus outbreak through contaminated centralized water supply system].

OBJECTIVE: To investigate the etiology and source of an infectious diarrhea outbreak and control the epidemic. METHODS: Through the retrospective cohort study, we had surveyed all the residents who complained symptoms of diarrhea or vomiting since Nov. 20th,2007 from the five villages in the north of town Y, and collected hygiene information on the water supply system of the five villages, the environment information of three villages and hygiene information of some case-indexed families, and tested the etiological biomarker, including nucleoside acid of norovirus through Real-time PCR and nested PCR technologies. RESULTS: From Nov. 24th to Dec. 3th in 2007, 435 diarrhea or vomiting cases were found in the north of Y town, where tap water A was supplied for daily use. The attack rate was 12.93%. The diarrhea cases were distributed among all country groups who has used tap water A and the attack rate was ranged from 5.21% (20/384) to 21.23% (100/471). Drinking the tap water A was significantly associated with an increased risk of infection (RR = 9.246, 95% CI: 6.25 -13.68). About 85.9% (262/ 305) of the cases were from Nov. 25th to 27th. An investigation of a country of S2 group showed that the incidence of different age groups was distributed as the following: 0 - year-old 20.0% (3/15); 10 - year-old 17.3% (9/52); 20 - year-old 15.2% (16/105); older than 60 year-old 23.3% (7/30). No statistical significance was identified between age and infection(chi2 = 1.15, P >0.05). Most of the patients were not serious and well prognostic, and no hospitalized or dead cases were reported. On site investigation and daily water quality monitoring showed that disinfection procedures were not strictly followed. The monitoring data also indicated the bacteriology index of tap water A was disqualified. The test of Salmonella, Shigella and Staphylococcus aureus were negative in two vomit and one stool samples from patients. Three specimens by Real-time PCR, and six by nested PCR were positive for norovirus among the three feces and three anal swabs samples. With the drinking water sterilization and health education, the epidemic had been controlled rapidly and effectively. CONCLUSION: The epidemic was a diarrhea outbreak that might be caused by norovirus through drinking the contaminated tap water A.

[A cross sectional survey on serum lipid level and its influencing factors in children aged 3-14 years in Guangdong province].

OBJECTIVE: To investigate the serum levels of cholesterol, triglyceride and high density lipoprotein cholesterol in children aged 3-14 years and its influencing factors. METHODS: The cross-sectional survey study population was a representative sample from Guangdong province obtained by multi-stage randomized cluster sampling. Serum lipids in 6188 children aged > or = 3 years were assayed using automatic biochemical instrument. The data of social and demographic status were collected by face-to-face interview, and height and weight were obtained by physical examination. RESULTS: The age-standardized and region-weighted means of serum total cholesterol (TC), triglyceride (TG), and high density lipoprotein cholesterol (HDL-C) were 0.80 mmol/L, 3.50 mmol/L and 1.28 mmol/L, respectively. For the mean of TG, there was no difference between metropolitan and middle city, nor between rich county and poor county. For TC, it was the highest in metropolitan, and there was no difference between rich and poor county. For HDL-C, the difference existed between every two regions. The age-standardized and region-weighted prevalence of high TG, high TC and low HDL-C were 2.2%, 2.1% and 8.0%, respectively. Metropolitan, rich county, low weight and age between 7.0-9.9 years are protecting factors for high TG, and the number of family between 3-4, age between 7.0-9.9, metropolitan, middle city and poor county are risk factors for high TC. Male, family income per year between 800-9999 RMB, middle city, rich county are protecting factors for low HDL-C. CONCLUSION: The prevalence of abnormal serum lipid was still low compared with other regions in China. The region, number of family member, age and sex may be the important factors influencing on serum lipid levels.

An enterovirus 71 epidemic in Guangdong Province of China, 2008: epidemiological, clinical, and virogenic manifestations.

Enterovirus 71 (EV71) is shown to be a major causative agent in outbreaks of hand, foot, and mouth disease (HFMD) reported in Guangdong (GD) Province of China in 2008. A total of 48,876 HFMD cases (131 severe and 21 fatal) were reported to the GD HFMD web-based surveillance system, which covers 871 clinics. The main causes of death included central nervous system damage, heart failure, and pulmonary edema. The incidence rate was 52 per 100,000, and the epidemic peak appeared in May and June. EV71 was found in 59% and coxsackievirus A16 in 26% of 936 laboratory-confirmed cases. Other viruses are likely to be responsible for the remaining 15% of cases. Of the 185 EV71 cases collected, 62% were mild, 27% were severe, and the remaining 11% were fatal. A total of 17 EV71 isolates were subjected to nucleotide sequencing of the entire VP1 gene. Phylogenetic analysis showed that the GD EV71 strains belonged to the C4 subgenotype and that EV71 circulates at a national rather than a regional level. A Comparison with the VP1 gene from a different clinical case showed that there was no obvious virulence determinant in this locus. Furthermore, this study found that most deaths occurred in rural areas, thereby indicating that delayed diagnosis and incorrect treatment may play an important role.

[Study on the events of nonfatal drowning among primary and middle school students in a rural town of Guangdong province, 2006].

OBJECTIVE: To understand the incidence and characteristics of nonfatal drowning among primary and middle school students in rural area and to provide basic information for intervention. METHODS: A rural town was selected and all students from 3th-8th grades, 10th grade and 11th grade were studied. All data were collected, using a self-administrated questionnaires which was guided by investigator. RESULTS: The overall incidence rate of nonfatal drowning was 5.65% (549/9732) and were 7.69%, 5.80%, 2.39% for primary, secondary and high school students, respectively. Male students had a higher rate (7.14%) than that of females (4.03%). The incidence rates of non-treated, treated in emergency and under hospitalization were 4.52%, 0.77% and 0.35%. The major reasons of drowning were swimming (46.88%), falling into waters (15.67%), diving (13.79%) and rescuing others (6.24%). The proportion of drowning occurred in the afternoon, evening, at noon or in the morning were 59.94%, 15.64%, 14.77% and 9.65% respectively. The common sites of drowning were river/lake (42.48%), swimming pool (19.56%), reservoir (11.39%) and pond (4.38%). 66.76% of the drowning cases were witnessed by other person, and 17.86% were conscious when being removed from waters. CONCLUSION: The incidence of nonfatal drowning among students in rural areas was high, and the natural body of waters was the most common site causing drowning while swimming was the major reason of drowning. Intervention targeting on primary and middle school students in rural should be carried out to reduce the incidence.

[Analysis on pedestrian traffic injury among aged 0-14 years children in Guangzhou, China].

OBJECTIVE: To describe the characteristics of child pedestrian traffic injuries among aged 0-14 years old in Guangzhou city and to provide information on road, vehicle and human injuries in pedestrian. METHODS: A database of all motor vehicle crashes involving child pedestrian traffic injury cases over a five-year period (2000-2004), was from the police department. RESULTS: The annual pedestrian traffic injury rates on incidence, mortality and case fatality were 17.63/ 1,100,000, 1.78/ 100,000 and 10.07% respectively. Both incidence rate and mortality peaked in the 5-9 age group were 26.80/ 100,000 and 2.57/ 100,000, with case fatality peaked in the 0-4 age group (13.29%). For males, the incidence (20.98/ 100,000) and mortality (2.00/ 100,000) were higher than that in females (13.83/ 100,000, and 1.52/ 100,000). The main injured parts of body would include multi-areas (40.34%), head (26.75%) and lower limbs (21.53%). 10.07% of the cases died and 66.18% and 23.75% of them having had severe and slight injures. The major causes were due to drivers (57.50%) and pedestrians (33.47%) faults with top three responsible vehicles were cars (40.14%), two-wheeled motorcycles (34.38%) and vans (22.15%). CONCLUSION: Data from pediatric pedestrian injury poses a threat to children and adolescents, data suggesting that it is important to change behaviors of both drivers and pedestrians.

Synthesis of C-nucleosides designed to participate in triplex formation with native DNA: specific recognition of an A:T base pair in DNA.

[structure: see text] We have previously described a system of 2-aminoquinoline- and 2-aminoquinazoline-based C-deoxynucleosides (TRIPsides) that are designed to be incorporated into oligomers that can specifically bind in the major groove via Hoogsteen base pairing to any sequence of native DNA. The four TRIPsides are termed antiGC, antiCG, antiTA, and antiAT with respect to the Watson-Crick base pair targets that they bind. The first three TRIPsides have been prepared, characterized, and shown to form stable and sequence-specific triplexes. In the present study, we describe the preparation of two molecules, 2-amino-4-(2'-deoxy-beta-D-ribofuranosyl)quinazoline (7) and 2-amino-6-fluoro-4-(2'-deoxy-beta-D-ribofuranosyl)quinoline (14), that can serve as the remaining antiAT TRIPside. The phosphoramidites of 7 and 14 were prepared, but only the latter was successfully incorporated into DNA oligomers. It is demonstrated using UV-visible melting experiments that 14 forms sequence-specific intramolecular triplets with A:T base pairs at physiological pH.

Molecular recognition via triplex formation of mixed purine/pyrimidine DNA sequences using oligoTRIPs.

Stable DNA triple-helical structures are normally restricted to homopurine sequences. We have described a system of four heterocyclic bases (TRIPsides) that, when incorporated into oligomers (oligoTRIPs), can recognize and bind in the major groove to any native sequence of DNA [Li et al., J. Am. Chem. Soc. 2003, 125, 2084]. To date, we have reported on triplex-forming oligomers composed of two of these TRIPsides, i.e., antiTA and antiGC, and their ability to form intramolecular triplexes at mixed purine/pyrimidine sequences. In the present study, we describe the synthesis and characterization of the antiCG TRIPside and its use in conjunction with antiTA and antiGC to form sequence-specific intra- and/or intermolecular triplex structures at mixed purine/pyrimidine sequences that require as many as four major groove crossovers.

Incorporation of cationic chains in the Dickerson-Drew dodecamer: correlation of energetics, structure, and ion and water binding.

We have investigated the unfolding thermodynamics for incorporating cationic side chains in the Dickerson-Drew dodecamer duplex. Incorporation of two 3-aminopropyl-2'-deoxyuridine residues (one on each self-complementary strand) lowers the stability of the duplex. This reduction is driven by unfavorable heat contributions due to the removal of electrostricted water and higher exposure of polar and nonpolar atomic groups that immobilize structural water. These cationic chains effectively remove counterions from the major groove, neutralizing some negatively charged phosphates. The overall results are consistent with the NMR solution of the modified duplex that showed a small bend at each modified site.

Structure of B-DNA with cations tethered in the major groove.

Here, we describe the 1.6-A X-ray structure of the DDD (Dickerson-Drew dodecamer), which has been covalently modified by the tethering of four cationic charges. This modified version of the DDD, called here the DDD(4+), is composed of [d(CGCGAAXXCGCG)](2), where X is effectively a thymine residue linked at the 5 position to an n-propyl-amine. The structure was determined from crystals soaked with thallium(I), which has been broadly used as a mimic of K(+) in X-ray diffraction experiments aimed at determining positions of cations adjacent to nucleic acids. Three of the tethered cations are directed radially out from the DNA. The radially directed tethered cations do not appear to induce structural changes or to displace counterions. One of the tethered cations is directed in the 3' direction, toward a phosphate group near one end of the duplex. This tethered cation appears to interact electrostatically with the DNA. This interaction is accompanied by changes in helical parameters rise, roll, and twist and by a displacement of the backbone relative to a control oligonucleotide. In addition, these interactions appear to be associated with displacement of counterions from the major groove of the DNA.

Triple helix forming TRIPside molecules that target mixed purine/pyrimidine DNA sequences.

A new strategy to form stable and sequence-specific triple helical DNA structures at mixed purine/pyrimidine sequences using a combination of four C-glycosides (TRIPsides) has been described [Li et al. (2003) J. Am. Chem. Soc. 125, 2084]. The partial realization of the approach is demonstrated by incorporating two of the four TRIPsides into oligomers that can potentially fold into intramolecular triplexes that contain one or two major groove crossovers of the purine Hoogsteen H-bond information. Using temperature-dependent electronic and fluorescence spectroscopy and differential scanning calorimetry, it is demonstrated that stable triplexes form at physiological conditions at non-homopurine targets. In addition, triplexes using the TRIPsides form in a highly sequence specific manner.

Design of triple helix forming C-glycoside molecules.

The modeling, synthesis, and characterization of oligomers containing 2-aminoquinazolin-5-yl 2'-deoxynucleotide residues are reported. The 2-aminoquinazoline residues sequence specifically bind via Hoogsteen base pairing as a third strand in the center of the major groove at T:A base pair Watson-Crick duplex sequences. Evidence for the formation of a sequence specific three-stranded structure is based on thermal denaturation UV-vis and fluorescence studies. The novel 2-aminoquinazoline C-nucleotide is a component of a system designed to overcome the homopurine requirement for triple helix structures.

[Study on the epidemiological characteristics of overweight and obesity among population aged eighteen and over in Guangdong Province in 2002].

OBJECTIVE: To describe the epidemiological characteristics of overweight and obesity among people aged 18 and over in Guangdong province in 2002, and to identify the populations and regions under high risk. METHODS: Cross-sectional survey was used through sampling on multi-stage randomized clusters. Data of socialeconomic status were collected by face-to-face interview. Data on weight and height was obtained through physical check-ups. RESULTS: A sample size of 15 130 people and the mean body mass index (BMI) was 22.03 +/- 3.38 with no significant difference between males and females. However the significant difference was seen between cities and rural areas. The crude prevalence rate of overweight and obesity were 16.8% and 1.8%, and the age-adjusted rate were 15.0% and 1.7%, respectively. The crude rate of overweight in cities (24.8%) and males (17.5%) were higher than that in rural areas (9.4%) and females (16.2%). The crude rate of obesity in cities was seen higher than that in the rural areas, but not significantly different between females and males. The results of logistic regression analysis showed that the major risk factors influencing overweight would include household income, age, gender, smoking habits, physical exercises and location of residence. CONCLUSION: About one sixth of the citizens in Guangdong province were considered to be overweighted and obesive had become an important public health problem. Integrated measures must be taken for prevention and control.