Total laparoscopic partial hepatectomy versus open partial hepatectomy for primary left-sided hepatolithiasis: study protocol for a randomized controlled trial.

BACKGROUND: The advantages of laparoscopic left-sided hepatectomy (LLH) for treating hepatolithiasis in terms of the time to postoperative length of hospital stay (LOS), morbidity, long-term abdominal wall hernias, hospital costs, residual stone rate, and recurrence of calculus have not been confirmed by a randomized controlled trial. The aim of this trial is to compare the safety and effectiveness of LLH with open left-sided hepatectomy (OLH) for the treatment of hepatolithiasis. METHODS: Patients with hepatolithiasis eligible for left-sided hepatectomy will be recruited. The experimental design will produce two randomized arms (laparoscopic and open hepatectomy) at a 1:1 ratio and a prospective registry. All patients will undergo surgery in the setting of an enhanced recovery after surgery (ERAS) programme. The prospective registry will be based on patients who cannot be randomized because of the explicit treatment preference of the patient or surgeon or because of ineligibility (not meeting the inclusion and exclusion criteria) for randomization in this trial. The primary outcome is the LOS. The secondary outcomes are percentage readmission, morbidity, mortality, hospital costs, long-term incidence of incisional hernias, residual stone rate, and recurrence of calculus. It will be assumed that, in patients undergoing LLH, the length of hospital stay will be reduced by 1 day. A sample size of 86 patients in each randomization arm has been calculated as sufficient to detect a 1-day reduction in LOS [90% power and α = 0.05 (two-tailed)]. The trial is a randomized controlled trial that will provide evidence for the merits of laparoscopic surgery in patients undergoing liver resection within an ERAS programme. CONCLUSIONS: Although the outcomes of LLH have been proven to be comparable to those of OLH in retrospective studies, the use of LLH remains restricted, partly due to the lack of short- and long-term informative RCTs pertaining to patients with hepatolithiasis in ERAS programmes. To evaluate the surgical and long-term outcomes of LLH, we will perform a prospective RCT to compare LLH with OLH for hepatolithiasis within an ERAS programme. TRIAL REGISTRATION: ClinicalTrials.gov NCT03958825. Registered on 21 May 2019.

[Neurovascular coupling responses and cognitive function: The impact of aging and the interventional effect of exercise].

Aging is a natural process accompanied with a progressive deterioration of cognitive functions. With an aging population, more and more elderly people are suffering from cognitive impairment. Previous studies have paid more attention to the impact of inflammation and oxidative stress on cognitive function during aging. Recently, it has been discovered that neurovascular coupling (NVC), a mechanism regulating cerebral blood flow, may play a significant role in aging-related cognitive impairment. NVC responses regulate the supply of energy substances and oxygen during brain activity, which in turn enhances cognitive function. However, as people grow older, NVC responses gradually weaken, which may be one of the mechanisms underlying aging-induced cognitive impairment. Given the important role of NVC responses in the brain, it is necessary to search for intervention methods that can improve NVC responses and promote cognitive function. Exercise is an effective means to delay aging and improve cognitive function. It also has a certain promoting effect on NVC responses. This article reviews the regulatory mechanisms of NVC responses, the relationship between NVC responses and cognitive function, and explores the effects of aging and exercise intervention on NVC responses, hoping to provide new research ideas for exercise intervention to improve NVC responses and promote cognitive function in the elderly.

Case Report: ECMO-Assisted Uniportal Thoracoscopic Tracheal Tumor Resection and Tracheoplasty: A New Breakthrough Method.

Primary tracheal tumors are seldom seen, and most of them are malignant. At present, the main treatment is surgical resection. It is rare to accomplish tracheal tumor resection and tracheoplasty via uniportalal thoracoscopy. In order both to maintain the patient's oxygen supply during surgery and to reduce the size of the surgical incision, we have innovatively integrated the ECMO-assisted and uniportal thoracoscopic techniques for the first time, perfectly achieving tracheal tumor resection and tracheoplasty. The intraoperative manipulation was only 180 min in duration. The patient returned to the intensive care unit and recovered smoothly after the surgery. The patient was discharged from the hospital 17 days after the operation. ECMO-assisted uniportal thoracoscopic tracheal resection and tracheoplasty provides a new idea and method for colleagues.

The application of rigid and flexible mediastinoscopy in esophagectomy: our experience and a new technology.

BACKGROUND: To avoid the inconvenience of triangulation among various rigid operating instruments in mediastinoscopy-assisted esophagectomy, we invented a new technique: used a flexible endoscope to mobilize thoracic esophagus and dissected mediastinal lymph nodes through the left cervical incision. This technology has not been reported so far. In this study, we introduce our long-term experience and demonstrate this new technique. METHODS: Twenty-nine patients with early esophageal cancer underwent mediastinoscopy-assisted esophagectomy in our hospital from June 2018 to September 2020. Among them, 12 patients used flexible mediastinoscopy, and 17 patients used conventional rigid mediastinoscopy and instruments to observe their therapeutic effect. RESULTS: There were no significant differences between the two groups in gender, average age, body mass index, incidence of adverse reactions, bleeding volume, and postoperative hospital stay. The operation time of flexible mediastinoscopy group was significantly shorter than that of rigid mediastinoscopy group (192.9 ± 13.0 vs 246.8 ± 6.9 min, p < 0.01). The number of lymph nodes removed by flexible endoscopy was significantly more than that of rigid endoscopy (8.5 ± 0.6 vs 6.0 ± 0.3, P < 0.01). Postoperative follow-up was completed for all patients, and the average follow-up time was 11.6 ± 7.2 months. During the follow-up period, no recurrence or death was observed. CONCLUSIONS: Mediastinoscopy-assisted esophagectomy is an effective way to treat early esophageal cancer. The application of flexible mediastinoscopy provides more convenience and better stability. It can facilitate the operation of the surgeon and lymph node dissection, which proved to be a feasible technology.

Catamenial pneumothorax with bubbling up on the diaphragmatic defects: a case report.

BACKGROUND: Catamenial pneumothorax is characterized by spontaneous recurring pneumothorax during menstruation, which is a common clinical manifestation of thoracic endometriosis syndrome. There are still controversies about its pathogenesis. CASE PRESENTATION: A 43-year-old woman with a history of endometriosis came to our hospital due to recurring pneumothorax during menstruation. Uniportal Video-assisted Thoracoscopic Surgery (VATS) exploration was performed on the eve of menstruating. We thoroughly explored the diaphragm, visceral and parietal pleura: The lung surface was scattered with yellowish-brown implants; no bullae were found; multiple diaphragmatic defects were found on the dome. And surprisingly, we caught a fascinating phenomenon: Bubbles were slipping into pleural cavity through diaphragmatic defects. We excised the diaphragmatic lesions and wedge resected the right upper lung lesion; cleared the deposits and flushed the thoracic cavity with pure iodophor. Diaphragmatic lesions confirmed the presence of endometriosis, and interestingly enough, microscopically, endometrial cells were shedding with impending menses. After a series of intraoperative operations and postoperative endocrine therapy, the disease did not recur after a period of follow-up. CONCLUSION: We have witnessed the typical signs of catamenial pneumothorax at the accurate timing: Not only observed the process of gas migration macroscopically, but also obtained pathological evidence of diaphragmatic periodic perforation microscopically, which is especially precious and confirms the existing theory that retrograde menstruation leads to diaphragmatic endometriosis, and the diaphragmatic fenestration is obtained due to the periodic activities of ectopic endometrium.

Key microRNAs and hub genes associated with poor prognosis in lung adenocarcinoma.

In the study, we obtained 36 pairs of lung adenocarcinoma (LUAD) tissues and adjacent non-tumorous tissues. Then, we chose a specific hub-target gene of miRNA and used qRT-PCR to evaluate the expression of PECAM1. We found that the expression level of PECAM1 mRNA in LUAD was significantly lower than that in adjacent nontumor tissues (P<0.0001). Univariate and multivariate analyses were conducted on 481 LUAD patients from The Cancer Genome Atlas (TCGA) according to the Cox proportional hazard regression model to evaluate the impact of PECAM1 expression and other clinicopathological factors on survival. The results showed that the low expression of PECAM1 was an important independent predictor of poor overall survival (HR, 0.704; 95% CI, 0.518-0.957; P = 0.025). Based on the Tumor Immune Estimation Resource (TIMER) database, the relationship between PECAM1 expression and B cell, CD8+ T cell, CD4+ T cell, macrophage, neutrophil, and dendritic cell infiltration was weak in LUAD (P<0.01). In particular, a more significant positive correlation between PECAM1 expression and HLA-complex members, CD1C, NRP1, and ITGAX expression in dendritic cell was detected in LUAD. The mechanism which PECAM1 involved in the development of LUAD may be closely related to changes in the immune microenvironment.

SP600125 enhances C-2-induced cell death by the switch from autophagy to apoptosis in bladder cancer cells.

BACKGROUND: A natural compound Jaspine B and its derivative possess potential anti-cancer activities; However, little is known about the underlying mechanism. Here, the role of a new autophagy inducer Jaspine B derivative C-2 in suppressing bladder cancer cells was researched in vitro and in vivo. METHODS: The underlying mechanisms and anticancer effect of C-2 in bladder cancer cells were investigated by MTT, western blotting, immunoprecipitation and immunofluorescence assays. The key signaling components were investigated by using pharmacological inhibitors or specific siRNAs. In vivo, we designed a C-2 and SP600125 combination experiment to verify the effectiveness of compound. RESULTS: C-2 exhibits cytotoxic effect on bladder cancer cells, and JNK activated by C-2 triggers autophagy and up-regulates SQSTM1/p62 proteins, contributing to activation of Nrf2 pathway. Utilization of JNK inhibitor SP600125 or knockdown of JNK by siRNA potentiate the cytotoxicity of C-2 through down-regulation of p62 and LC3II proteins and up-regulation of active-Caspase3 proteins, enhance the cell death effect, facilitating the switch from autophagy to apoptosis. In vivo study, C-2 suppresses tumor growth in a xenograft mouse model of EJ cells without observed toxicity. Combined treatment with SP600125 further enhances tumor inhibition of C-2 associated with enhanced activation of caspase3 and reduction of autophagy. CONCLUSIONS: It reveals a series of molecular mechanisms about SP600125 potentiate the cytotoxicity and tumor inhibition of C-2 in bladder cancer cells through promoting C-2-induced apoptosis, expecting it provides research basis and theoretical support for new drugs development.

Molecular surveillance of coxsackievirus A16 reveals the emergence of a new clade in mainland China.

Coxsackievirus A16 (CV-A16) of the genotypes B1a and B1b have co-circulated in mainland China in the past decades. From 2013 to 2017, a total of 3,008 specimens from 3,008 patients with mild hand, foot, and mouth disease were collected in the present study. Viral RNA was tested for CV-A16 by a real-time RT-PCR method, and complete VP1 sequences and full-length genome sequences of CV-A16 strains from this study were determined by RT-PCR and sequencing. Sequences were analyzed using a series of bioinformatics programs. The detection rate for CV-A16 was 4.1%, 25.9%, 10.6%, 28.1% and 12.9% in 2013, 2014, 2015, 2016 and 2017, respectively. Overall, the detection rate for CV-A16 was 16.5% (497/3008) in this 5-year period in Shenzhen, China. One hundred forty-two (142/155, 91.6%) of the 155 genotype B1 strains in the study belonged to subgenotype B1b, and 13 (13/155, 8.4%) strains belonged to subgenotype B1a. Two strains (CVA16/Shenzhen174/CHN/2017 and CVA16/Shenzhen189/CHN/2017) could not be assigned to a known genotype. Phylogenetic analysis of these two strains and other Chinese CV-A16 strains indicated that these two CV-A16 strains clustered independently in a novel clade whose members differed by 8.4%-11.8%, 8.4%-12.1%, and 14.6%-14.8% in their nucleotide sequences from those of Chinese B1a, B1b, and genotype D strains, respectively. Phylogenetic analysis of global CV-A16 strains further indicated that the two novel CV-A16 strains from this study grouped in a previously uncharacterized clade, which was designated as the subgenogroup B3 in present study. Meanwhile, phylogenetic reconstruction revealed two other new genotypes, B1d and B4, which included a Malaysian strain and two American strains, respectively. The complete genome sequences of the two novel CV-A16 strains showed the highest nucleotide sequence identity of 92.3% to the Malaysian strain PM-15765-00 from 2000. Comparative analysis of amino acid sequences of the two novel CV-A16 strains and their relatives suggested that variations in the nonstructural proteins may play an important role in the evolution of modern CV-A16.

Complete Genome Sequence of an Enterovirus A71 Strain Isolated in 2006 from a Patient in Shenzhen, Southern China, with a Lethal Case of Enterovirus Infection.

The whole-genome sequence of an enterovirus A71 strain (EV71/SHENZHEN001/2006) isolated in 2006 from a patient with a fatal case of enterovirus infection was determined. Phylogenetic analysis based on the complete VP1 gene classified this strain as subgenotype C4a.

Synthesis, Crystal Structure, Spectroscopic Properties, and Interaction with Ct-DNA of Zn(II) with 2-Aminoethanethiol Hydrochloride Ligand.

The zinc(II) complex (C2H6NS)2Zn·ZnCl2 was synthesized with 2-aminoethanethiol hydrochloride and zinc sulfate heptahydrate as the raw materials in aqueous solution. The composition and structure of the complex were characterized by elemental analysis, infrared spectra, single crystal X-ray diffraction, and thermogravimetry. The crystal structure of the zinc(II) complex belongs to monoclinic system, space group P 21/n, with cell parameters of a = 0.84294(4), b = 0.83920(4), c = 1.65787(8) nm, Z = 2, and D = 2.041 g/cm(3). In this paper, the interaction of complex with Ct-DNA was investigated by UV-visible and viscosimetric techniques. Upon addition of the complex, important changes were observed in the characteristic UV-Vis bands (hyperchromism) of calf thymus DNA and some changes in specific viscosity. The experimental results showed that the complex is bound to DNA intercalative (intercalation binding).

Activation of calcium-sensing receptor increases TRPC3/6 expression in T lymphocyte in sepsis.

Sepsis is a systemic inflammatory response syndrome induced by infection. T Lymphocytes play an important role in this disease. Transient receptor potential (TRP) channels and calcium-sensing receptors (CaSR) are expressed in lymphocytes to promote intracellular Ca(2+) release. However, data about the link between CaSR and TRP channels in septic T lymphocytes are few. In this study, by Ca(2+) imaging and Western blotting, we found that in septic rat peripheral blood T lymphocytes expressions of TRPC3 and TRPC6 proteins are higher. The SR/ER Ca(2+) ATPase inhibitor thapsigargin (TG) and CaSR agonist NPS R-568 also increased expressions of TRPC3 and TRPC6 proteins, which were reversed by PLC-IP3 channel blocker U73122 and TRPC channels inhibitor SKF96365. By Ca(2+) imaging, we found that the depletion of ER Ca(2+) stores by TG elicited a transient rise in cytoplasmic Ca(2+), followed by sustained increase depending on extracellular Ca(2+). But, SKF96365, not Verapamil (L-type channels inhibitor) and NiCl2 (Na(+)/Ca(2+) exchanger inhibitor), inhibited the relatively high [Ca(2+)]i. NPS R-568 also resulted in the same effect, and the duration of [Ca(2+)]i increase was eliminated completely by U73122 and was reduced in the absence of [Ca(2+)]o. NPS R-568 and TG increased the apoptotic ratio of septic T lymphocytes, which can be suppressed by SKF96365 and U73122. These results suggested that CaSR activation promoted the expression of TRPC3 and TRPC6 and enhanced T lymphocytes apoptosis through PLC-IP3 signaling pathway in sepsis.

Calcium-sensing receptor in the T lymphocyte enhanced the apoptosis and cytokine secretion in sepsis.

Calcium-sensing receptor (CaSR) is a member of the G protein-coupled receptor superfamily that existed in lymphocytes and promoted cytokine secretion. Lymphocytes are also involved in sepsis. However, the role of CaSR in lymphocytes in sepsis is unclear. In this study, we want to examine whether the CaSR in lymphocytes in sepsis is involved in the cytokine secretions and apoptosis and make clear the relationship between NF-κB and MAPK signal transduction pathways. We investigated the issues mentioned earlier using Western blotting, ELISA, and Flow Cytometry. The sepsis was remodeled by cecal ligation and puncture (CLP). We found that CaSR protein expression increased in the peripheral blood T lymphocytes in CLP rats. The calcimimetic R568 (NPS R568) promoted, whereas the calcilytic NPS 2143 attenuated, signaling pathways proteins P65 (subunit of NF-κB), ERK1/2, and JNK (one subgroup of MAPKs) phosphorylation. However, P-P38 and P-JAKs exhibit no significant changes. Furthermore, the production TNF-α and IL-4 was greater in CLP rats than in normal rats, and NPS R568 promoted secretion of these cytokines. Simultaneously, the apoptotic ratio of T cells in CLP increased, and NPS R 568 exacerbated the apoptosis degree. However, these effects could also be inhibited by U0126 or SP600125 (MAPKs pathway inhibitor) or Bay-11-7082 or (NF-κB pathway inhibitor). From these results, we can conclude that, in the sepsis, CaSR activation promoted T-cell apoptosis and the secretion of pro-inflammatory cytokine TNF-α and anti-inflammatory cytokines IL-4 probably through NF-κB and partial MAPK signal transduction pathways.

Forecasting influenza epidemics from multi-stream surveillance data in a subtropical city of China.

BACKGROUND: Influenza has been associated with heavy burden of mortality and morbidity in subtropical regions. However, timely forecast of influenza epidemic in these regions has been hindered by unclear seasonality of influenza viruses. In this study, we developed a forecasting model by integrating multiple sentinel surveillance data to predict influenza epidemics in a subtropical city Shenzhen, China. METHODS: Dynamic linear models with the predictors of single or multiple surveillance data for influenza-like illness (ILI) were adopted to forecast influenza epidemics from 2006 to 2012 in Shenzhen. Temporal coherence of these surveillance data with laboratory-confirmed influenza cases was evaluated by wavelet analysis and only the coherent data streams were entered into the model. Timeliness, sensitivity and specificity of these models were also evaluated to compare their performance. RESULTS: Both influenza virology data and ILI consultation rates in Shenzhen demonstrated a significant annual seasonal cycle (p<0.05) during the entire study period, with occasional deviations observed in some data streams. The forecasting models that combined multi-stream ILI surveillance data generally outperformed the models with single-stream ILI data, by providing more timely, sensitive and specific alerts. CONCLUSIONS: Forecasting models that combine multiple sentinel surveillance data can be considered to generate timely alerts for influenza epidemics in subtropical regions like Shenzhen.

[2009 evolution for VP4 of enterovirus 71 strains in Shenzhen].

OBJECTIVE: To analyze the genetic evolution for the common causative agent of hand, foot and mouth disease(HFMD) that VP4 of human enterovirus 71 in Shenzhen district. METHOD: 491 sttol specimen were collected from, children with hand, foot and mouth diease in Shenzhen Children's Hospital 2009. After cell culture, VP4 gene of eight EV71 strains were amplified by reverse-transcriptase PCR( RT-PCR), phylogenetic analysis of the VP4 gene was constructed by using MEGA 4. 0. RESULT: The VP4 gene of eight EV71 strains encoding 69 amino acids with full length 207 bp. The nucleotide homology of VP4 gene among eight EV71 strains was 94. 2% -98. 1%, compared with VP4 gene of EV71 strains retrieved from Shenzhen 2001 to 2004 and GenBank was 89. 1%-98. 1% and 79.2%-100% respectively. Asian epidemic strain Fuyang had the highest nucleotide homology, representative strain C4 and Shenzhen strain (AY895144) with 94. 2% -98. 1% secondly. Except for the 54th amino acid of VP4 gene of India reported strain and one of the eight EV71 strains, the homology of the rest amino acids between the eight EV71 strains and those in GenBank was 100%. Compared with representative strain C4,there were seventeen differences in nucleotide sequences of VP4 of the eight EV71 strains. All of the different nucleotides were located at the degenerate password sites except one. There was no significant difference in VP4 gene between the severe and the mild cases of strainS. The eight Shenzhen EV71 strains were classified as sub-genotype C4 in the phylogenetic tree. CONCLUSIONS: The epidemic of EV71 in Shenzhen 2009 was sub-genotype C4. VP4 gene of EV71 was very conservative which dose not belong to the variation section. The variation of most of nucleotide was invalid variation. The amino acids encoded by VP4 gene which variation was almost zero.

Cross sectional survey of influenza antibodies before and during the 2009 pandemic in Shenzhen, China.

Much information is available for the 2009 H1N1 influenza immunity response, but little is known about the antibody change in seasonal influenza before and during the novel influenza A pandemic. In this study, we conducted a cross-sectional serological survey of 4 types of major seasonal influenza in March and September 2009 on a full range of age groups, to investigate seasonal influenza immunity response before and during the outbreak of the sH1N1 influenza in Shenzhen - the largest migration city in China. We found that the 0-5 age group had an increased antibody level for all types of seasonal influenza during the pandemic compared to the pre-outbreak level, in contrast with almost all other age groups, in which the antibody level decreased. Also, distinct from the antibodies of A/H3N2, B/Yamagata and B/Victoria that decreased significantly during the 2009 H1N1 pandemic, the antibody of A/H1N1 showed no statistical difference from the pre-outbreak level. The results suggest that the antibodies against the 2009 sH1N1 cross-reacted with seasonal H1N1. Moreover, the 0-5 age group was under attack by both seasonal and 2009 H1N1 influenza during the pandemic, hence vaccination merely against a new strain of flu might not be enough to protect the youngest group.

[Applicability of a sensitive duplex real-time PCR assay for identifying B/Yamagata and B/Victoria lineages of influenza virus].

OBJECTIVE: To develop a novel sensitive duplex real-time PCR assay for accurately identifying B/Yamagata and B/Victoria lineages of influenza virus type B. METHODS: 50 HA (hemagglutinin) gene sequences coding for B/Yamagata and B/Victoria lineage, respectively, were randomly downloaded for GenBank and analyzed by software MEGA. Primers and probes specific for HA gene of B/Yamagata and B/Victoria lineages were designed by Primer Primer and then applied in the duplex real-time RT-PCR method that was followed developed. Influenza virus B type and A type isolated in our laboratory and typing-confirmed by HAI method were used as reference strains to determine the specificity of this assay and the sensitivity of the duplex amplification was evaluated by viral load testing in terms of in vitro transcribed RNA copy number. RESULTS: In 2006-2010, 793 influenza virus type B strains were isolated from 17 765 throat swab samples, among which 152 strains were differentiated as By lineage and 641 as Bv lineage by this assay. These results was agreement with that determined by HAI assay. This developed assay allows to accurately identify approximately 10(2) copies/microl for Bv and By lineage virus with intra- and inter-coefficient of variation (CV) < 3.5% and nearly 100% specificity. CONCLUSIONS: This method provides sensitive and robust tool for routine diagnosis and on-time epidemiological examination of influenza virus, which could be applied in influenza surveillance laboratories for rapid molecular diagnosis.

[Compare real-time RT-PCR with two culture methods for influenza virus detection].

OBJECTIVE: Real-time RT-PCR, cell culture and embryonated eggs culture for influenza detection were compared by analyzing the data of influenza surveillance in Shenzhen in second half of 2009. METHODS: 1092 clinical samples (throat swabs) collected during second half of 2009 were tested by real-time RT-PCR, cell culture and embryonated eggs culture, and the results were analyzed by statistical methods. RESULTS: The positive rate were 54.21%, 27.11% and 16.21% using real-time RT-PCR, cell culture and embryonated eggs culture, and the sensitive were 100%, 50% and 29.9%. The lowest dilutions of virus detected by real-time RT-PCR were 10(-2) TCID50/ml. CONCLUSION: The sensitive of real-time RT-PCR was higher than culture and the specificity was also very high. It was more suitable for emergency detect. The sensitive of cell culture for H3N2 subtype was higher, and sensitive of embryonated eggs culture for type B was higher.

Three fatal cases of pandemic 2009 influenza A virus infection in Shenzhen are associated with cytokine storm.

China had taken strict measures for pandemic 2009 H1N1 infection with enhanced surveillance and hospital isolation since April 2009. In Shenzhen, over 1200 confirmed cases of H1N1 infection were identified. Three young patients died of severe pneumonia. Among them, two boys developed neurological complications. Cytokine storm seemed an important cause.

[Analyses of serological and genetic characteristics on novel H1N1 influenza A virus from the infected patient in Shenzhen].

Analysis of serological and genetic characteristics on 2009 swine-origin influenza A (H1N1) virus (S-OIV) isolated from four patients with severe disease in Shenzhen were performed. Microneutralization assay showed that the neutralizing antibody titers of the infected patients did not exceed 1 : 20 in a short term post infection, which could not neutralize the viruses efficiently. Hemagglutination inhibition (HI) tests confirmed that the antigenicity of S-OIV from the patients was distinct from the seasonal influenza A virus, but similar to the reference strains of S-OIV. Phylogenetic and molecular analysis showed that S-OIV from the patients still belonged to the classical swine lineages and did not have the genetic characteristics of highly pathogenic influenza virus. Several amino acid residue mutations on HA protein were detected, which seemed not to affect the virulence and pathogenicity of the viruses. Further, A His 275 Tyr mutation on NA protein of a virus strain was detected, which induced the oseltamivir resistance of the virus.

[Epidemiological and molecular characterization of seasonal influenza A/H3N2 viruses circulating in Shenzhen, 2005 - 2007].

OBJECTIVE: To determine the epidemiological characteristics of seasonal influenza in Shenzhen from 2005 to 2007 and the molecular variation of HA1 domain of influenza H3N2 viruses. METHODS: The consultation rate for influenza-like illness (ILI) were calculated weekly for indicating the influenza activities (the Shenzhen Influenza Surveillance System mainly consisted of 16 institutions with 9 hospitals, 6 districts and one municipal centers of disease control and prevention). Pharyngeal swabs from the cases of ILI, which were collected during 2005 to 2007 from the city-wide and quality-controlled surveillance network, were used to propagate the viruses. The HA1 region of the influenza A/H3N2 viruses were detected by RT-PCR and sequenced subsequently. The analyses of pairwise amino acid variations, genetic clustering and phylogenetics was performed. RESULTS: The activity levels of influenza showed certain changes during each year from 2005 to 2007, and there were summer peaks from May to July in 2006 and 2007. The positive rates of influenza virus were 4.78% (114/2385), 5.77% (212/3674) and 12.12% (343/2831) from 2005 to 2007 respectively. The weekly isolating rates changed accordingly with the trend of the percentages of ILI. The proportions of influenza H3N2 virus were 25.46% (28/114) and 2.83% (6/212) in 2005 and in 2006 respectively, but the proportion increased to 62.68% (215/343), which indicated that H3N2 virus became the predominant strain in 2007. Phylogenetic clustering analysis of influenza H3N2 virus revealed that there were 5 clades. The viruses which were isolated in 2005 contained in the clade I and II, the viruses in 2006 were comprised in clade III, and clade IV and V included the viruses isolated in 2007. Although the stem of cladogram developed with one accord of the time isolated viruses, the viruses which were similar to vaccine strains had circulated in Shenzhen before a given strain was determined as vaccine strain by WHO. It was also noticed that more amino acid changes at antigenic sites, especially at sites A and B in the H3N2 viruses, were found in 2007 than that in 2005 and in 2006. But the sequences at the receptor-binding sites and disulphide bond sites were conserved and no new circulating strain for genetic reassortment had been found in the period. CONCLUSION: Shenzhen might be one of areas where the ongoing genetic drift of influenza H3N2 viruses appeared earlier in China. The changes of influenza H3N2 virus showed the active status in the population. The results suggested that monitoring seasonal influenza viruses by sequence analysis could provide important and timely information on the appearance of strains with epidemiologic significance.