[Analysis on the cluster epidemic of coronavirus disease 2019 in Guangdong Province].

Objective: Analysis of clustering characteristics of coronavirus disease 2019 (COVID-19) in Guangdong Province. Methods: The COVID-19 cases in Guangdong Province onset from January 1 to February 29, 2020 were collected from Chinese information system for disease control and prevention and Emergency Public Reporting System. Obtain the epidemiological survey data of the cluster epidemic situation, and clarify the scale of cluster epidemic situation, the characteristics of the index cases, family and non-family subsequent cases. Calculate serial interval according to the onset time of the index cases and subsequent cases, secondary attack rate based on the close contacts tracking results, the characteristics of different cases in the clustered epidemic were compared. Results: A total of 283 cluster were collected, including 633 index cases, 239 subsequent cases. Families are mainly clustered, the total number involved in each cluster is in the range of 2-27, M (P25, P75) are 2.0 (2.0, 4.0). During January 15 to February 29, the secondary attack rate is 2.86% (239/8 363) in Guangdong Province, the family secondary attack rate was 4.84% (276/3 697), and the non-family secondary attack rate was 1.32% (61/4 632). According to the reporting trend of the number of cases in Guangdong Province, it can be divided into four stages, the rising stage, the high platform stage, the descending stage and the low level fluctuation period. The secondary attack rate of the four stages were 3.5% (140/3 987), 2.3% (55/2 399), 2.6% (37/1 435), 1.3% (7/542), respectively. The difference was statistically significant (P=0.003). Conclusion: COVID-19 cluster mainly occurs in families in Guangdong Province. The scale of the clustered epidemic was small; the serial interval was short; and the overall secondary attack rate was low.

[Clinical outcomes of COVID-19 cases and influencing factors in Guangdong province].

Objective: To analyze the clinical courses and outcomes of COVID-19 cases and the influencing factors in Guangdong province and provide basis for the formulation or adjustment of medical care and epidemic control strategy for COVID-19. Methods: We collected demographic data, medical histories, clinical courses and outcomes of 1 350 COVID-19 patients reported in Guangdong as of 4 March 2020 via epidemiological investigation and process tracking. Disease severity and clinical course characteristics of the patients and influencing factors of severe illness were analyzed in our study. Results: Among 1 350 cases of COVID-19 cases in Guangdong, 72 (5.3%) and 1 049 (77.7%) were mild and ordinary cases, 164 (12.1%) were severe cases, 58 (4.3%) were critical cases and 7 (0.5%) were fatal. The median duration of illness were 23 days (P(25), P(75): 18, 31 days) and the median length of hospitalization were 20 days (P(25), P(75): 15,27 days). For severe cases, the median time of showing severe manifestations was on the 12(th) day after onset (P(25), P(75): 9(th) to 15(th) days), and the median time of severe manifestation lasted for 8 days (P(25), P(75): 4, 14 days). Among 1 066 discharged/fetal cases, 36.4% (36/99) and 1.0% (1/99) of the mild cases developed to ordinary cases and severe cases respectively after admission; and 5.2% (50/968) and 0.6% (6/968) of the ordinary cases developed to severe cases, and critical cases respectively after admission. In severe cases, 11.4% developed to critical cases (10/88). The influencing factors for severe illness or worse included male (aHR=1.87, 95%CI: 1.43-2.46), older age (aHR=1.67, 95%CI: 1.51-1.85), seeking medical care on day 2-3 after onset (aHR=1.73, 95%CI: 1.20-2.50) pre-existing diabetes (aHR=1.75, 95%CI: 1.12-2.73) and hypertension (aHR=1.49, 95%CI: 1.06-2.09). Conclusions: The course of illness and length of hospitalization of COVID-19 cases were generally long and associated with severity of disease clinical outcomes. The severe cases were mainly occurred in populations at high risk. In the epidemic period, classified management of COVID-19 cases should be promoted according to needs for control and prevention of isolation and treatment for the purpose of rational allocation of medical resources.

[Application of modified Dix-Hallpike maneuver in the diagnosis of posterior semicircular canal benign paroxysmal positional vertigo].

Objective:To investigate the application of modified Dix-Hallpike maneuver in the diagnosis of posterior semicircular canal benign paroxysmal positional vertigo. Method:The modified Dix-Hallpike maneuver, supine roll maneuver and classical Dix-Hallpike maneuver were performed respectively. The sensitivity and specificity of modified and classical Dix-Hallpike maneuver in the diagnosis of posterior semicircular canal BPPV was compared. Result:Fifty-five posterior semicircular canal BPPV patients showed both modified and classical Dix-Hallpike maneuver positive result, including 12 cases of rotational nystagmus induced by ipsilateral supine roll maneuver. Conclusion:Modified Dix-Hallpike maneuver and classical Dix-Hallpike maneuver have the same effect on the diagnosis of posterior semicircular canal BPPV, but the former is easy to the operation, nystagmus observation and result judgment, and is conducive to the promotion of use..

[Epidemiological characteristics of influenza in Guangdong province, during winter of 2017-2018].

Objective: To understand the epidemiological characteristics of influenza in Guangdong province, during the winter of 2017-2018, to provide evidence for response to the diversity of influenza, in different seasonal patterns. Methods: Data on weekly influenza surveillance from January 2016 to April 2018, were collected in Guangdong. Information on patients with Influenza-like illness (ILI), on influenza virus positive rates and on outbreaks during the winter of 2017 to 2018, was analyzed and compared with those in spring of 2016 and summer of 2017. χ(2) test and Fisher exact test were used. Results: In the above said winter, the average percentage of visits for ILI in 28 hospitals where sentinel surveillance program had been set, was 4.99% (157 235/3 149 656), which was above the level of the same period in the previous five years. The positive rates of influenza virus among samples collected from ILI outpatients and hospitalized cases under severe acute respiratory infection (SARI) were 28.33% (2 137/7 543) and 14.93% (256/1 715), with the proportions of B (Yamagata) as 70.43% (1 505/2 137) and 73.05% (187/256) respectively. A total of 257 influenza outbreaks were reported in the winter period, with 82.49% (212/257) occurred in elementary schools. Cases aged 6-14 years occurred in winter and spring appeared of having higher positive rate than those seen in summer (P<0.05) whereas elderly cases aged 60 and above showed higher positive rate in summer than those in winter and spring two seasons (P<0.05). Conclusions: Epidemiological characteristics of influenza appeared in Guangdong province, during the winter from 2017 to 2018, were correlated to Influenza B (Yamagata). Capacity on the implementation of surveillance programs and on the coverage of vaccination should be improved and increased in order to control influenza in different epidemic seasons, in Guangzhou.

The epidemiology of hepatitis B virus infection in women of reproductive age in highly endemic areas in China.

We describe the epidemiology of hepatitis B virus (HBV) infection among women of reproductive age residing in areas of China that are highly endemic for chronic HBV, and provide evidence useful for decision-makers to guide strategies for preventing mother-to-child transmission of HBV, and assess the impact of perinatal transmission PMTCT by projecting HBsAg prevalence trends without interventions. We conducted a cross-sectional HBV serological survey of women, 15-49 years of age, residing in Fujian, Guangdong, Guangxi and Hainan provinces. Demographic and other subject-level data were collected in face-to-face interviews, after which we obtain blood specimens. Specimens were tested for HBV sero-markers by ELISA (Beijing Wantai Biological Pharmacy), and HBV DNA was tested with PCR (Hunan Sansure Biotech). Weighted HBsAg and HBV (either HBsAg+ or anti-HBc+ indicating either present or past infection) prevalences were 11.82% and 57.16%, respectively. Among the HBsAg-positive women, 27% were also HBeAg positive. The proportion of individuals with HBV DNA loads >105 IU/mL declined with increasing age. Among HBsAg-negative women, 0.9% had occult HBV infection. The prevalence of chronic HBV infection among reproductive women in these highly endemic provinces is high, posing a threat to maternal health and risk of mother-to-child transmission. Prevention of mother-to-child transmission remains critically important.

Development and characterization of novel SSR markers in Siniperca kneri Garman.

In this study, 37 transcriptome-derived simple sequence repeat (SSR) markers and 18 genomic SSR markers were developed and characterized in the Chinese perch, Siniperca kneri Garman. The average allele number per locus was 5.1 (range: 2-8) for transcriptome-derived SSRs and 3.8 (range: 2-5) for genomic SSRs. The average observed and expected heterozygosities were 0.666 (range: 0.000-1.000) and 0.692 (range: 0.230-0.857) for transcriptome-derived SSRs, respectively. These values were 0.380 (range: 0.000-1.000) and 0.527 (range: 0.201-0.799) for genomic SSRs, respectively. The average polymorphic information content was 0.638 (range: 0.215-0.824) for transcriptome-derived SSRs and 0.477 (range: 0.183-0.752) for genomic SSRs. Seven of these loci exhibited departure from Hardy-Weinberg equilibrium after sequential Bonferroni's correction for multiple tests, and no significant deviation was observed for the linkage disequilibrium. These developed and characterized markers are anticipated to be useful for studies on population genetics, conservation genetics, and the fishery management of this species.

New microsatellite loci for the mandarin fish Siniperca chuatsi and their application in population genetic analysis.

The mandarin fish is a popular fresh water food fish in China. Fifty-three polymorphic microsatellite markers were isolated through construction of an enriched library of genomic DNA of Siniperca chuatsi (Percichthyidae). We found 2 to 7 alleles per locus. The observed and expected heterozygosity values varied from 0.059 to 1.000 and from 0.305 to 0.818, respectively. The polymorphic information content value varied from 0.255 to 0.782. Twelve microsatellite loci deviated significantly from Hardy-Weinberg equilibrium after Bonferroni's correction. These markers were evaluated in five species of sinipercine fish; 98% of the 265 locus/taxon combinations tested gave cross-amplification. Eight polymorphic microsatellite markers were randomly selected for genetic characterization of three S. chuatsi populations. The Ganjiang River and Yuanjiang River populations had moderate levels of genetic diversity, while the Mudanjiang River population had a relatively low level genetic diversity. Genetic distance-based cluster analysis showed clustering of the Ganjiang River and Yuanjiang River populations in a single group and the Mudanjiang River population in a separate group. Based on these results, we suggest that S. chuatsi from the Yangtze River watershed are distinct from the Mudanjiang River population. These SSR markers will be useful for diversity, mapping and marker assisted studies of S. chuatsi and other sinipercine fishes.

cDNA cloning and characterization of two trehalases from Spodoptera litura (Lepidoptera; Noctuidade).

The oriental leafworm moth, Spodoptera litura, is a major agricultural pest in southeast Asia and nearby Pacific regions. Two distinct trehalases have been identified in insects: soluble trehalase (Treh1) and membrane-bound trehalase (Treh2), although there is currently no information on these genes in S. litura. To characterize the distribution and function of treh, cDNAs of Treh proteins were cloned from S. litura. SpoliTreh1 cDNA has an open reading frame of 1758 nucleotides, which encodes a protein of 585 amino acids, with a predicted mass of approximately 67.07 kDa and an isoelectric point of 4.86. SpoliTreh2 cDNA has an open reading frame of 2325 nucleotides, encoding a protein of 645 amino acids, a mass of approximately 73.62 kDa, and an isoelectric point of 5.90. Northern blotting analysis revealed that SpoliTreh1 transcripts are in the midgut, fat body, tracheae, and epidermis, but not in the brain and Malpighian tubules of S. litura larvae, whereas SpoliTreh2 transcripts were found in all 6 tissues. SpoliTreh1 transcripts were highly expressed in the fat body of the pre-pupal stage, and SpoliTreh2 transcripts were highly expressed in the fat body of 3-day-old larvae of the 6th instar and during the 1st 6 days of the pupal stage, except the 2nd day. Both SpoliTreh1 and SpoliTreh2 were highly expressed in third-instar larvae.

A population-based study on incidence and economic burden of influenza-like illness in south China, 2007.

OBJECTIVES: The disease burden of influenza-like illness (ILI) in most tropical and subtropical countries has not been described adequately to date. The aim of this study was to determine the epidemiology and incidence of ILI, and to assess the economic burden in south China. STUDY DESIGN: Prospective study. METHODS: A population-based household survey was conducted quarterly in 2007 in Guangdong Province. RESULTS: The average number of subjects in each quarterly survey was 13,687. In total, 1002 cases of self-reported ILI were identified in all four surveys, indicating an annual incidence of 7.23 cases of ILI per 100 persons. The second quarter had the highest incidence of ILI (2.83 cases per 100 persons). Children aged 1-4 years, <1 year and 5-9 years had the highest annual incidence rates of ILI (49.87, 35.19 and 21.24 cases per 100 persons, respectively). The incidence of ILI was significantly higher in males than females (P < 0.001), and significantly higher in rural residents than urban residents (P < 0.001). The individual cost per episode of ILI represented approximately 20% of monthly per-capita income of residents. CONCLUSIONS: The results of this large-scale household study confirm that ILI places a substantial health and economic burden on south China. Ultimately, the results of this study will provide further information for understanding the disease burden of influenza in subtropical areas.

Quantum computing.

Quantum computing is a quickly growing research field. This article introduces the basic concepts of quantum computing, recent developments in quantum searching, and decoherence in a possible quantum dot realization.

[Protective effects of SMT on myocardial ultrastructure of ischemia reperfusion injury in heart of rat].

AIM: To Investigate the myocardial ultrastructure effects of SMT on the ischemia reperfusion injury (IRI) in the rat heart. METHODS: Eighteen Spraqua-Dawley rats were randomly divided into three groups: ischemia reperfusion group (IR), subjected to 60 min of o-cclusion and 20 min of reperfusion of the anterior descending branch of left coronary artery; IR + SMT group (SMT), given the selective iNOS inhibitor S-methylisothiourea sulfate (SMT, 5 mg/kg, i.v.) before reperfusion; control group (C), didn't occlude coronary artery after exposing heart and observed 80 min. Electrocardiogram (ECG) was recorded. Nitrite and nitrate content were measured in myocardium and blood serum. The changes of myocardial ultrastructure were observed with electron microscope. RESULTS: Ischemia reperfusion induced ST segment elevation and T waves inversion or tallness in ECG, damaged myocardial ultrastructure, increased nitrite and nitrate content in myocardium and blood serum after IR compared with before IR(P < 0.01). Administration of SMT improved the changes of ECG and the injury of myocardial ultrastructure. Nitrite and nitrate content of myocardium were lower than IR group (P < 0.05). The change of nitrite and nitrate level of blood serum in SMT group was nearly in C group. CONCLUSION: SMT can prevent myocardium injury from reperfusion following ischemia.

[The changes in the heart and erythrocyte L-arginine transport of spontaneously hypertensive rats].

Changes of L-arginine/nitric oxide pathway in heart and of L arginine transport in erythrocytes and their relationship were investigated in spontaneously hypertensive rats (SHR). 12 and 16 weeks old SHR, 16 weeks old SHR with captopril treatment for 4 weeks and 16 weeks old Wistar-Kyoto (WKY) rats were used. L arginine transport of myocardial ventricular tissue and erythrocytes, total nitric oxide synthase (tNOS) activity, nitrite and nitrate (NO(2) + NO(3)) and cyclic GMP (cGMP) content in myocardium were measured. The result showed that in myocardial ventricular tissue of SHR L-arginine transport decreased significantly with V(max) of the high-affinity transport being decreased by 24.3% (P<0.05, 12W group), 36.4% (P<0.01, 16W group) as compared with WKY group. Michaelis constant (K(m)) of low affinity transport was significantly lower than that of WKY group. NO(2) + NO(3) and cGMP content were respectively decreased by 24.6%, 19.8% (P>0.05, P<0.05, 12W group), 52.5%, 60.4% (P<0.05, P<0.01, 16W group) and 14.8%, 23% (P>0.05, P<0.05, SHR+C group) as compared with WKY group. But the K(m) of L-arginine high-affinity transport and the V(max) of low affinity transport and tNOS activity were not significantly changed. In erythrocytes, the changes of L-arginine transport coincided with those of myocardial tissue. The V(max) had significant positive correlation with the V(max) of high-affinity transport in myocardial tissue, r=0.5606, P=0.01 and had negative correlation with left ventricular weight to body weight radio, r=0.6231,P<0.01. These results indicate that the activity of L-arginine/nitric oxide pathway inhibited in myocardial tissue of SHR. The correlation between the inhibitory degree of L-arginine/nitric oxide pathway and the degree of ventricular hypertrophy is negative. The changes of L-arginine transport in erythrocytes coincide with those in myocardium.

[Effects of myocardial ischemia reperfusion injury on L-arginine/nitric oxide system in rat heart].

Ischemia reperfusion injury (IRI) model of rat heart was prepared by preperfusion for 15 min, then a suspension for 45 min and recycling reperfusion for 15 min with 30 ml KH buffer. The leakage of lactate dehydrogenase(LDH),protein, myoglobin and nitrite (NO2-) in the circular perfusion fluid were measured. Myocardial nitric oxide synthase(NOS) activity and L-arginine transport were observed. In the IR group, the leakage of LDH,protein, myoglobin and NO2- were increased respectively by 4.1,5.4,1 and 1.2 times(P<0.01) and NOS(tNOS, iNOS, cNOS) activity by 48.2%,43.2% and 52.1%,(P<0.01,respectively) as compared with the control group. L-arginine transport might be mediated by either high- or low-affinity transport system in cardiac tissue. In the IR group, L-arginine transport increased significantly with the V(max) being increased by 48% and 2 times respectively for the low-affinity and the high-affinity transport as compared with control. Michaelis constant (km) was decreased by 47.4% for low-affinity transport (P<0.05),but not significantly changed for the high-affinity transport. These results suggest that the increase of nitric oxide generation might result from the increased myocardial NOS activity and L-arginine transport during IRI.

[Inhibition of signal transduction pathways of endothelin-1-induced proliferation of vascular smooth muscle cells by nitric oxide].

The signal transduction pathways of the inhibitory effect of nitric oxide (NO) on endothelin (ET)-induced proliferation of vascular smooth muscle cells (VSMCs) were studied. 3H-thymidine (TdR) incorporation, mitogen-activated protein kinase (MAPK) activity and protein kinase C (PKC) activity of cultured VSMCs of rabbits thoracic aorta were measured in the presence of either NO precursor L-arginine (L-Arg) or NO donor 3-morpholino sydnonimine-hydrochloride (SIN-1), or ET-1 alone or with L-Arg or SIN-1. The results show: (1) ET-1 (10(-8) mol/L) significantly increased VSMCs 3H-TdR incorporation (5 times, P < 0.01), MAPK activity (4 times, P < 0.01) and PKC activity (3 times, P < 0.01), as compared with control. L-Arg or SIN-1 alone was without effect on 3H-TdR incorporation, MAPK activity and PKC activity. (2) When ET-1 and L-Arg (2, 5, 10 mmol/L) were simultaneously administered, 3H-TdR incorporation and activity of both MAPK and PKC were all significantly decreased in comparison with the ET group. (3) When ET-1 + SIN-1 (5, 10, 50 mumol/L), the effects coincide with those of the ET-1 + L-Arg groups. These findings indicate that NO inhibition of the signal transduction pathways of the ET-1-induced proliferation of VSMCs may be mediated by the inhibition of ET-1-induced activation of both PKC and MAPK.

Tumour necrosis factor-alpha (TNF-alpha) gene polymorphism and expression in pre-eclampsia.

Pre-eclampsia is an endothelial disorder and TNF-alpha has fundamental effects on endothelial cells by several means, including altering the balance between oxidant and anti-oxidant, changing the pattern of prostaglandin production and affecting expression of several cell surface components. To determine whether TNF-alpha mRNA expression is increased in pre-eclamptic patients, leucocytes from pre-eclamptic patients, normal pregnant women and normal non-pregnant women were studied for TNF-alpha expression using a quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) method. Using a model of 373A ABI Sequencer, TNF-alpha gene polymorphism was also analysed by GENESCAN and Genotyper software in order to explain the mechanism of abnormal TNF-alpha expression. Our results show that TNF-alpha mRNA expression is significantly elevated in pre-eclamptic patients compared with the other two control groups. The high expression of TNF-alpha may be associated with the TNF1 allele, whose frequency is markedly increased in pre-eclamptic patients. These observations are consistent with a major role for TNF-alpha in mediating endothelial disturbances, and suggest a key role for TNF-alpha in the development of pre-eclampsia.

[The central mechanism of pressor response induced by infusing 7.5% sodium chloride solution in hemorrhagic hypotension dog].

Nine pairs of dogs were operated with head cross circulation and four pairs of dogs with brain cross circulation. Bleeding of formoral artery decreased the mean arterial pressure to 5.33 kPa and maintained for 30 min. In each pair of A dog 10% of total blood lose was infused intravenously by 7.5% NaCl solution (as test) or normal saline (as control), but B dog was not treated. The results showed that in the test group the arterial blood pressure recovered immediately in both A and B dogs and lasted for more than 60 min after infusion. The recovery value of systolic pressure was higher than diastolic pressure and pulse pressure increased. In the control group the blood pressure recovered slightly but of no statistical significance. There was no remarkable difference in heart rate between the two groups. A marked decrease in hematocrit appeared after bleeding and infusion, but there was no significant difference between the two groups (P > 0.05). Plasma sodium increased significantly after infusion in A dogs of the test group (P < 0.01), but the change in B dogs was the same in the control group. These results mentioned above indicate that the central nervous system plays important role on the mechanism of pressor response induced by infusing 7.5% NaCl solution in the hemorrhagic hypotension dog.

Clinical experience with triphasic oral contraceptive (Triquilar) in 527 women in China.

From October 1987 to May 1989, a total number of 527 women completed a total of 6,291 treatment cycles in 6 centers in China for the study of a triphasic oral contraceptive - Triquilar. The mean age of subjects was 30.21 +/- 2.84 years. There were 7 pregnancies during the study period. Among them, five were patient failures because of missed pill or incorrect intake; one had taken barbiturates along with Triquilar. Only one woman became pregnant in the 11th treatment cycle without any reason being found. In most cases, menstrual flow decreased and dysmenorrhea improved as treatment continued. Of the total treatment cycles, the incidence of missed withdrawal bleeding was 0.25%, spotting 0.97%, and breakthrough bleeding 0.48%. Nausea and vomiting was the most common side effect and accounted for 6.4% of the total treatment cycles. This was followed by breast tenderness (3.7%), dizziness (2.4%) and headache (1.6%). Most of the side effects occurred during the first few cycles and were alleviated later. By the end of one year, the total dropout was 64 cases. The reasons for discontinuing treatment were: pregnancy 1.33 (per hundred women), menstrual disturbances 0.76, side effects 3.80, other medical reasons 2.09, and personal reasons 4.18. The results confirm that Triquilar is an effective oral contraceptive with good cycle control and low incidence of side effects. No serious reaction has been reported. It has been well accepted by the Chinese women. However, due to the low dosage of steroids, it is of utmost importance to avoid errors in its use.(ABSTRACT TRUNCATED AT 250 WORDS)