[Current status and considerations on clinical application of function-preserving pancreatic surgery].

For pancreatic neoplasms, the current clinical treatment strategy is mainly using standard surgical methods, including pancreaticoduodenectomy, distal pancreatectomy with splenectomy, and total pancreatectomy. Standard surgical methods require a larger resection, including resection of some surrounding organs and a large amount of pancreatic parenchyma. The endocrine and exocrine functions of the pancreas are easily damaged. Moreover, since the standard surgical procedure involves the reconstruction of the digestive tract at multiple anastomoses, there is a high risk of pancreatic, biliary, and intestinal fistulas occurring postoperatively. Therefore, function-preserving pancreatic surgery is recommended for some benign and low-grade pancreatic neoplasms. This type of surgery can treat pancreatic diseases while preserving more peripancreatic organs, pancreatic parenchyma and relatively complete digestive tract continuity, thereby improving the patient's short-term and long-term quality of life. In addition, with the development of laparoscopy and da Vinci robotic technology, minimally invasive technology-assisted pancreatic surgery has been carried out in clinical practice. They have been shown to be sufficiently safe and effective. This article reviews several common clinical pancreatic function-preserving surgical methods and their corresponding clinical applications and technical development status from the perspectives of preserving more peripancreatic organs, preserving more pancreatic parenchyma, and promoting pancreatic function recovery.

Discrete, Chiral Polymer-Insulin Conjugates.

Polymer conjugation has been widely used to improve the stability and pharmacokinetics of therapeutic biomacromolecules; however, conventional methods to generate such conjugates often use disperse and/or achiral polymers with limited functionality. The heterogeneity of such conjugates may lead to manufacturing variability, poorly controlled biological performance, and limited ability to optimize structure-property relationships. Here, using insulin as a model therapeutic polypeptide, we introduce a strategy for the synthesis of polymer-protein conjugates based on discrete, chiral polymers synthesized through iterative exponential growth (IEG). These conjugates eliminate manufacturing variables originating from polymer dispersity and poorly controlled absolute configuration. Moreover, they offer tunable molecular features, such as conformational rigidity, that can be modulated to impact protein function, enabling faster or longer-lasting blood glucose responses in diabetic mice when compared to PEGylated insulin and the commercial insulin variant Lantus. Furthermore, IEG-insulin conjugates showed no signs of decreased activity, immunogenicity, or toxicity following repeat dosing. This work represents a significant step toward the synthesis of precise synthetic polymer-biopolymer conjugates and reveals that fine tuning of synthetic polymer structure may be used to optimize such conjugates in the future.

Effect of ciprofol on induction and maintenance of general anesthesia in patients undergoing kidney transplantation.

OBJECTIVE: This study aims at evaluating the effects of ciprofol on the induction and maintenance of general anesthesia in patients undergoing kidney transplantation. PATIENTS AND METHODS: This prospective, randomized, single-blind study enrolled 120 patients aged 18-65 years who underwent general anesthesia for kidney transplantation. The patients were randomized into a ciprofol group (group C) and a propofol group (group P). Anesthesia induction: group C had injected IV with ciprofol 0.4 mg/kg, group P had injected IV with propofol 2.0 mg/kg, while both groups had injected IV with sufentanil 0.4-0.5 µg/kg and cisatracurium 0.2 mg/kg. Anesthesia maintenance: ciprofol was injected IV with 0.8-2.4 mg•kg-1•h-1 in group C, propofol was injected IV with 4-12 mg•kg-1•h-1 in group P, while remifentanil was injected IV with 8-15 µg•kg-1•h-1 and cisatracurium was injected IV with 0.1-0.2mg•kg-1•h-1, with the bispectral index (BIS) maintained at 40-60 during the operation. RESULTS: The success rate of sedation in both groups was 100%. Compared with the P group, in group C the time of disappearance of the eyelash reflex and a decline in the BIS to 60 was shorter (p<0.001); the time of awakening was prolonged (p<0.001); the number of sedative drugs administered was reduced (p<0.001); MAP fluctuated less five mins after transplantation (p<0.01); the incidence of injection pain during induction was reduced (p<0.001) and intraoperative hypotension was decreased(p<0.01). CONCLUSIONS: Ciprofol is safe and effective for anesthesia induction and maintenance in kidney transplantation and its sedative effect is better than that of propofol.

[Combined resection of thoracic and abdominal organ clusters: a series of 50 cases].

Objective: To examine the technique and effect of combined thoracic and abdominal organ clusters resection. Methods: From February 2019 to August 2021, totally 50 cases of combined thoracoabdominal organ cluster resection were completed at Transplant Medical Center, the Second Affiliated Hospital of Guangxi Medical University from donation after brain death donors. There were 47 males and 3 females, aging (34.8±12.3) years (range: 5 to 55 years). The length of hospital stay(M(IQR)) was 4(4) days (range: 2 to 43 days), the length of tube time was 4(2) days (range: 1 to 43 days). Through the midsternal incision and the abdominal grand cross incision, the cold perfusion was performing simultaneously when the perfusion lines of each target organ was established respectively. The combined resection was performed with the diaphragm as the boundary and the organ cluster as the unit. The heart and lung were separated on site and sent to the transplant hospital, and the abdominal organ cluster was directly preserved and returned to our hospital for further separation and repair. Results: Totaly 21 hearts, 47 pairs of lungs, 49 livers, 47 pairs of kidneys and 11 pancreas were harvested by this surgical treatment. The resection time was (32.6±6.5) minutes (range: 19 to 50 minutes), with no hot ischemia time. There was no accidental injury that affected organ quality and function. Heart transplantation was performed in 17 cases, combined heart-kidney transplantation in 2 cases, double lung transplantation in 43 cases, single lung transplantation in 6 cases, liver transplantation in 41 cases, combined liver-pancreas-duodenal cluster transplantation in 1 case, combined liver-kidney transplantation in 3 cases, combined pancreas-kidney transplantation in 9 cases, and kidney transplantation in 74 cases. Conclusion: Simultaneous perfusion and combined resection of thoracic and abdominal organ clusters for donation after brain death donors are feasible and effective.

[Low-frequency pulsed electromagnetic fields promote osteoblast mineralization and maturation of rats through the PC2/sAC/PKA/CREB signaling pathway].

OBJECTIVE: To explore whether the effect of low-frequency pulsed electromagnetic fields (PEMFs) in promoting osteoblast mineralization and maturation is related to the primary cilia, polycystin2 (PC2) and sAC/PKA/CREB signaling pathway. METHODS: We detected the expression levels of PC2, sAC, PKA, CREB and their phosphorylated proteins in primary rat calvarial osteoblasts exposed to 50 Hz 0.6 mT PEMFs for 0, 5, 15, 30, 60, 90, and 120 min. We blocked PC2 function with amiloride hydrochloride and detected the changes in the activity of sAC/PKA/CREB signal pathway and the mineralization and maturation of the osteoblasts. These examinations were repeated in the osteoblasts after specific knockdown of PC2 via RNA interference and were the co-localization of PC2, sAC, PKA, CREB and their phosphorylated proteins with the primary cilia were using immunofluorescence staining. The expressions of PC2 and the signaling proteins of sAC/PKA/CREB pathway were detected after inhibition of primary ciliation by RNA interference. RESULTS: The expression levels of PC2, sAC, p-PKA and p- CREB were significantly increased in the osteoblasts after exposure to PEMFs for different time lengths (P < 0.01). Blocking PC2 function or PC2 knockdown in the osteoblasts resulted in failure of sAC/PKA/CREB signaling pathway activation and arrest of osteoblast mineralization and maturation. PC2, sAC, p-PKA and p-CREB were localized to the entire primary cilia or its roots, but PKA and CREB were not detected in the primary cilia. After interference of the primary cilia, PEMFs exposure no longer caused increase of PC2 expression and failed to activate the sAC/PKA/CREB signaling pathway or promote osteoblast mineralization and maturation. CONCLUSION: PC2, located on the surface of the primary cilia of osteoblasts, can perceive and transmit the physical signals from PEMFs and promote the mineralization and maturation of osteoblasts by activating the PC2/ sAC/PKA/CREB signaling pathway.

Identification and Verification of the Ability of Cdk5 to Phosphorylate Deubiquitinating Enzyme BRCC3 In Vitro.

It is known that the expression of the deubiquitinating enzyme BRCA1-BRCA2-containing complex subunit 3 (BRCC3) and cyclin-dependent protein kinase 5 (Cdk5) is increased in Parkinson's disease (both are involved in neuroinflammatory response). However, the regulatory mechanism of Cdk5 on the post-translational modification of BRCC3 remains unclear. Here we studied whether Cdk5 phosphorylates BRCC3. Phosphorylation of BRCC3 by Cdk5 was predicted by GPS 5.0 software. His-BRCC3 plasmid was constructed by cloning the BRCC3 gene into pGEX-6P-1 vector, and then His-BRCC3 fusion protein was induced with isopropyl ß-d-1-thiogalactopyranoside and purified using His-Tag affinity chromatography purification agarose. Phosphorylation of BRCC3 fusion protein by Cdk5 in vitro was detected by mass spectrometry and Western blotting. The results showed that multiple phosphorylation sites were predicted by GPS 5.0, and the His-BRCC3 fusion protein was successfully induced and purified. In vitro kinase assay, Western blotting, and mass spectrometry showed that Cdk5 can phosphorylate BRCC3. It has been demonstrated that protein kinase Cdk5 can phosphorylate the deubiquitinating enzyme BRCC3 in vitro, which provides new data for further study on the mechanism of neurodegeneration.

Parental Views on the Non-Operative Management of Simple Appendicitis in Children: Results of a Cross-Sectional Survey.

BACKGROUND: To determine parental attitudes for the non-operative management of simple appendicitis and determine willingness to participate in research evaluating different management options. METHOD: Voluntary cross-sectional survey of parents/guardians presenting to paediatric outpatient department. Likert scale of 0-10 (strongly disagree-strongly agree) was utilised, analysis by individual question responses. Results are presented as medians [IQR], paired t test, the Mann-Whitney U test and Kruskal-Wallis test analysis as appropriate. A p value of < 0.05 is considered significant. RESULTS: Of 311 respondents, 81% (252/311) completed all the questions. The majority (73%, 220/303) believed that appendicitis needed an urgent operation, and 88% (264/299) believed that perforated appendicitis was a life-threatening condition. Fifty-two per cent (131/252) preferred operative management, and 48% (121/252) preferred antibiotic treatment. The most important factors influencing treatment choice were removal of pain (84%, 246/293), removal of infection (83%, 244/293) and minimising complications (54%, 162/293). Concerns regarding antibiotic treatment included the potential for recurrence (75%, 204/271), the risk of progression (63%, 170/271) and the potential of future surgery (53%, 145/271). The perceived beneficial factors of antibiotic treatment included avoiding surgery, 64% (173/269) and surgical complications 68% (184/269). When asked to consider whether they would participate in clinical research evaluating the two treatment options, parents were equally in favour (39%), against (26%) or unsure (35%). CONCLUSION: Our study demonstrates equipoise in the parental acceptance of antibiotics as a treatment simple appendicitis in children, or participation in research evaluating this topic. However, the important factors that may influence this decision have been identified to guide future conversations.

Photoswitchable Sol-Gel Transitions and Catalysis Mediated by Polymer Networks with Coumarin-Decorated Cu24 L24 Metal-Organic Cages as Junctions.

Photoresponsive materials that change in response to light have been studied for a range of applications. These materials are often metastable during irradiation, returning to their pre-irradiated state after removal of the light source. Herein, we report a polymer gel comprising poly(ethylene glycol) star polymers linked by Cu24 L24 metal-organic cages/polyhedra (MOCs) with coumarin ligands. In the presence of UV light, a photosensitizer, and a hydrogen donor, this "polyMOC" material can be reversibly switched between CuII , CuI , and Cu0 . The instability of the MOC junctions in the CuI and Cu0 states leads to network disassembly, forming CuI /Cu0 solutions, respectively, that are stable until re-oxidation to CuII and supramolecular gelation. This reversible disassembly of the polyMOC network can occur in the presence of a fixed covalent second network generated in situ by copper-catalyzed azide-alkyne cycloaddition (CuAAC), providing interpenetrating supramolecular and covalent networks.

Visible-light-mediated, additive-free, and open-to-air controlled radical polymerization of acrylates and acrylamides.

Oxygen tolerance in ontrolled radical polymerizations has been an active field of study in recent years. Herein, we report a photocontrolled, additive-free iniferter polymerization that operates in completely open vials utilizing the "polymerizing through oxygen" mechanism. Trithiocarbonates are directly activated with high intensity 450 nm light to produce narrowly dispersed (M w/M n = 1.1-1.6) polyacrylates and polyacrylamides in only 1 hour of irradiation. Living behavior is demonstrated through chain extension, block copolymer synthesis, and control over molecular weight through varying the monomer:iniferter ratio. A slight increase in induction period is observed for the open vial polymerization compared to the air-free reaction, but polymers with similar M n and M w/M n values are produced after 30-60 minutes of irradiation. This system will provide a convenient platform for living additive manufacturing because of its fast reaction time, air tolerance, wide monomer scope, and lack of any additives beyond the monomer, iniferter, and DMSO solvent.

[Surgical treatment for Cushing's disease with negative results in high dose dexamethasone suppression tests].

Objective: To analyze the indication and the outcome of trans-sphenoidal surgery (TSS) in Cushing's disease (CD) with negative high dose dexamethasone suppression tests (HDDST) results. Methods: Eighteen cases of ACTH-dependent Cushing's syndrome (CS) with negative HDDST results in the Department of Neurosurgery in Shanghai Ruijin Hospital from January 2015 to December 2017 were retrospectively reviewed. All patients underwent TSS. There were 5 males and 13 females, with an average age of (41±14) years. Results: All patients underwent bilateral inferior petrosal sinus sampling (BIPSS) before the surgery and got evidence of pituitary origin of ACTH secretion. They were thus indicated for TSS. Immediate post-operative remission was achieved in ratio 17/18. There were no recurrences within a flow-up of 1 to 3 years. Pituitary ACTH secreting adenomas were pathologically confirmed in 15 cases, including the one who did not achieve post-operative remission. Thus, all 18 patients with negative HDDST results can finally be confirmed as CD. Conclusions: HDDST alone is not sufficient to eliminate CD. For patients with ACTH-dependent CS with negative HDDST results, BIPSS should be further performed. The fact of post-operative remission and the pathological confirm of ACTH secreting pituitary adenoma may add final evidence to the diagnosis of CD.

Analysis of EEG Lemple-Ziv complexity and correlative aspects before and after treatment of anti-syphilis therapy for neurosyphilis.

Objective To investigate the diagnostic value of electroencephalogram (EEG) complexity in patients with neurosyphilis by comparing the changes of electroencephalogram Lempel-Ziv complexity (EEG-LZC) before and after anti-syphilis treatment. Methods The EEG complexity of neurosyphilis patients diagnosed in our hospital from July in 2015 to June in 2017 was analyzed and compared with other diagnostic results such as serology examination and cerebrospinal fluid examination. Results A total of 27 patients were diagnosed, including 19 males and 8 females, of which 6 were mesenchymal(cerebrospinal membrane and meningeal vascular), 16 were parenchymal(paralytic dementia, spinal cord tuberculosis and optic neuropathy), and 5 were asymptomatic. After intensive anti-syphilis therapy, the LZC increased significantly in all patients while the trend and degree of change were consistent with other diagnostic results. Conclusion The LZC can be used as one of the diagnostic indexes meanwhile the trend and degree of its change can be used as the reference index of curative effect to neurosyphilis.

Inhibition of JMJD6 expression reduces the proliferation, migration and invasion of neuroglioma stem cells.

Neuroglioma is the most common form of human primary malignant brain tumor, more and more studies recently showed only a small subpopulation of glioma cells which called glioma stem cells have true tumorigenic potential. Meanwhile, it was reported the overexpression of JMJD6 protein is closely involvement with the occurrence and development of multiple tumors, and JMJD6 is required for the differentiation of multiple organ, tissues and cells during embryogenesis. However, the influence of JMJD6 overexpression on neuroglioma development is unclear now. Hence, to explore the effects of JMJD6 expression on neuroglioma, we firstly isolated glioma stem cells by using CD133 MicroBead Kit, and identified via neurosphere-forming assay and Immunofluorescence staining. At the same time, we investigated the effects and mechanism of JMJD6 on the proliferation, migration and invasion of glioma stem cells through MTT, transwell assays and the Cignal finder cancer 10-pathway reporter array. The results demonstrated that the glioma neurosphere cells positively expressed stem cell marker SOX2, neuroectodermal stem cell marker Nestin, and also expressed astrocytes marker GFAP and neurons marker ß-tubulin III fter FBS-induced differentiation for a week, which proved the glioma neurosphere cells have the self-renewal and multipotential differentiation capacity. Moreover, shRNA lentiviral vector mediated knockdown of JMJD6 in glioma stem cells led to decreased proliferation, migration and invasion, the underlying molecular mechanism is related to the weaken of Wnt signaling pathway and strengthen of p53 signaling pathway.

Single-center study on transplantation of livers donated after cardiac death: A report of 6 cases.

Effective use of all available donated organs is critical, in order to meet the increasing demand for transplants. The present study explored liver transplantation with livers that were donated following cardiac death (DCD). According to the guidelines established by The Red Cross Society of China, 42 DCD organs were procured. Selected donors were treated with extracorporeal membrane oxygenation (ECMO) prior to the organ retrieval. The present single-center study included 6 liver transplantations of DCD organs (5 liver transplants and 1 liver-kidney combined transplant). All 6 recipients had a successful recovery without significant complications. The serum alanine transaminase, total bilirubin and international normalized ratio returned to the normal levels within a short period of time following transplantation, and the liver function remained normal during the follow-up period, which lasted up to 24 months. The present report demonstrated the feasibility of orthotopic liver transplantation using DCD livers. The pre-conditioning DCD donors and optimization of the recipient's condition using ECMO, played a crucial role in ensuring the success of transplantation.

Juvenile myelomonocytic leukaemia-associated mutation in Cbl promotes resistance to apoptosis via the Lyn-PI3K/AKT pathway.

Juvenile myelomonocytic leukaemia (JMML) is an aggressive myeloproliferative neoplasm in children characterized by granulocyte macrophage colony-stimulating factor (GM-CSF) hypersensitivity and resistance to chemotherapy. We recently identified c-Cbl (henceforth referred to as Cbl) as a GM-CSF receptor (GMR) responsive protein that targets Src for ubiquitin-mediated destruction upon GM-CSF stimulation and showed that a loss of negative regulation of Src is pivotal in the hyperactivation of GMR signalling in JMML cells. However, the mechanism regulating the chemoresistant nature of JMML has remained largely unknown. Here, we show that the JMML-associated Cbl mutant in complex with the Src family kinase Lyn promotes Cbl's adapter function, leading to increased association to PI3K regulatory subunit p85 and Lyn-dependent AKT pro-survival signalling. Notably, molecular or pharmacologic inhibition of the Lyn-PI3K/AKT pathway, but not the Ras/mitogen-activated protein kinase signalling axis, markedly increased the sensitivity of the otherwise chemoresistant Cbl mutant-JMML cells to chemotherapeutic agents currently used in the treatment of JMML patients. These results support the potential translational benefit of combining modalities that inhibit Lyn-PI3K/AKT signalling with traditional antileukaemia agents in the management of JMML.

Scaffold evaluation of liguzinediol analogs as novel cardiotonic agents.

Liguzinediol (LZDO) could mediate the positive inotropic effects through sarcoplasmic reticulum Ca2+ ATPase-dependent mechanism without the risk of arrhythmia. However, the pharmacophore of LZDO contributed to the activities was not clear. The aim of this work was to explore the relationship between positive inotropic effect and scaffold of LZDO as well as to check whether the pharmacophore of LZDO on anti-heart failure activity was located at the pyrazine ring. A series of LZDO analogs (3a-b, 4a-b, 9-19) were designed and synthesised, and their activities were evaluated on isolated heart contractility by Langendorff perfusion. The results showed that the efficacy of LZDO was reduced when the hydroxyl, carboxyl or ester moieties at the side chain position of LZDO were induced, and the para-dihydroxy in LZDO was necessary for its activity. Thus, the pharmacophore of the positive inotropic effect might be located at the whole scaffold of LZDO, but not at the pyrazine ring. The finding may provide an important clue of the pharmacophore for the development of novel cardiotonic agents.

Modeling of hysteresis in gene regulatory networks.

Hysteresis, observed in many gene regulatory networks, has a pivotal impact on biological systems, which enhances the robustness of cell functions. In this paper, a general model is proposed to describe the hysteretic gene regulatory network by combining the hysteresis component and the transient dynamics. The Bouc-Wen hysteresis model is modified to describe the hysteresis component in the mammalian gene regulatory networks. Rigorous mathematical analysis on the dynamical properties of the model is presented to ensure the bounded-input-bounded-output (BIBO) stability and demonstrates that the original Bouc-Wen model can only generate a clockwise hysteresis loop while the modified model can describe both clockwise and counter clockwise hysteresis loops. Simulation studies have shown that the hysteresis loops from our model are consistent with the experimental observations in three mammalian gene regulatory networks and two E.coli gene regulatory networks, which demonstrate the ability and accuracy of the mathematical model to emulate natural gene expression behavior with hysteresis. A comparison study has also been conducted to show that this model fits the experiment data significantly better than previous ones in the literature. The successful modeling of the hysteresis in all the five hysteretic gene regulatory networks suggests that the new model has the potential to be a unified framework for modeling hysteresis in gene regulatory networks and provide better understanding of the general mechanism that drives the hysteretic function.

PI3K/Akt mediates expression of TNF-alpha mRNA and activation of NF-kappaB in calyculin A-treated primary osteoblasts.

OBJECTIVE: The effect of calyculin A (CA), a serine/threonine protein phosphatase inhibitor, on tumor necrosis factor-alpha (TNF-alpha) in primary osteoblasts was investigated to determine whether protein phosphatases could affect primary osteoblasts and if so which signaling pathways would be involved. MATERIALS AND METHODS: Primary osteoblasts were prepared from newborn rat calvaria. Cells were treated with 1 nM CA for different time periods. The expressions of TNF-alpha and GAPDH mRNA were determined by RT-PCR. Cell extracts were subjected to SDS-PAGE and the activation of Akt and NF-kappaB were analyzed by western blotting. RESULTS: Calyculin A-treatment markedly increased the expression of TNF-alpha mRNA and enhanced the phosphorylation level of Akt (Ser473) in these cells. Pretreatment with the PI3K inhibitor LY294002 suppressed the increase in TNF-alpha mRNA expression and the phosphorylation of Akt in response to CA. Western blot analysis showed that CA stimulated the phosphorylation and nuclear translocation of NF-kappaB in primary osteoblasts, and these responses were blocked by pretreatment with LY294002. CONCLUSION: Calyculin A elicits activation of PI3K/Akt pathway which leads to expression of TNF-alpha mRNA and activation of NF-kappaB. This NF-kappaB activation involves both phosphorylation and nuclear translocation of NF-kappaB.

Sexual hormones in human skin.

The skin locally synthesizes significant amounts of sexual hormones with intracrine or paracrine actions. The local level of each sexual steroid depends upon the expression of each of the androgen- and estrogen-synthesizing enzymes in each cell type, with sebaceous glands and sweat glands being the major contributors. Sebocytes express very little of the key enzyme, cytochrome P450c17, necessary for synthesis of the androgenic prohormones dehydroepiandrosterone and androstenedione, however, these prohormones can be converted by sebocytes and sweat glands, and probably also by dermal papilla cells, into more potent androgens like testosterone and dihydrotestosterone. Five major enzymes are involved in the activation and deactivation of androgens in skin. Androgens affect several functions of human skin, such as sebaceous gland growth and differentiation, hair growth, epidermal barrier homeostasis and wound healing. Their effects are mediated by binding to the nuclear androgen receptor. Changes of isoenzyme and/or androgen receptor levels may have important implications in the development of hyperandrogenism and the associated skin diseases such as acne, seborrhoea, hirsutism and androgenetic alopecia. On the other hand, estrogens have been implicated in skin aging, pigmentation, hair growth, sebum production and skin cancer. Estrogens exert their actions through intracellular receptors or via cell surface receptors, which activate specific second messenger signaling pathways. Recent studies suggest specific site-related distribution of ERalpha and ERbeta in human skin. In contrast, progestins play no role in the pathogenesis of skin disorders. However, they play a major role in the treatment of hirsutism and acne vulgaris, where they are prescribed as components of estrogen-progestin combination pills and as anti-androgens. These combinations enhance gonadotropin suppression of ovarian androgen production. Estrogen-progestin treatment can reduce the need for shaving by half and arrest progression of hirsutism of various etiologies, but do not necessarily reverse it. However, they reliably reduce acne. Cyproterone acetate and spironolactone are similarly effective as anti-androgens in reducing hirsutism, although there is wide variability in individual responses.

Emergence and predominance of an H5N1 influenza variant in China.

The development of highly pathogenic avian H5N1 influenza viruses in poultry in Eurasia accompanied with the increase in human infection in 2006 suggests that the virus has not been effectively contained and that the pandemic threat persists. Updated virological and epidemiological findings from our market surveillance in southern China demonstrate that H5N1 influenza viruses continued to be panzootic in different types of poultry. Genetic and antigenic analyses revealed the emergence and predominance of a previously uncharacterized H5N1 virus sublineage (Fujian-like) in poultry since late 2005. Viruses from this sublineage gradually replaced those multiple regional distinct sublineages and caused recent human infection in China. These viruses have already transmitted to Hong Kong, Laos, Malaysia, and Thailand, resulting in a new transmission and outbreak wave in Southeast Asia. Serological studies suggest that H5N1 seroconversion in market poultry is low and that vaccination may have facilitated the selection of the Fujian-like sublineage. The predominance of this virus over a large geographical region within a short period directly challenges current disease control measures.