ObjectiveTo explore the feasibility， evaluation methods and metabolic differences of high-fat diet（HFD） combined with myocardial ischemia-reperfusion injury（MIRI） to establish a rat model of myocardial ischemia-reperfusion with phlegm and blood stasis blocking collaterals syndrome（PBSBCS）. MethodsThirty-two SD rats were randomly divided into the sham operation， HFD， MIRI， and MIRI+HFD groups. Rats in the sham operation and MIRI groups were fed a standard diet（regular chow）， while the HFD and MIRI+HFD groups received a HFD for 10 weeks. Rats in the MIRI and MIRI+HFD groups underwent myocardial ischemia-reperfusion surgery， while the sham operation group underwent only thread placement without ligation. Cardiac function was assessed via small-animal echocardiography， including left ventricular ejection fraction（EF）， left ventricular fractional shortening（FS）， cardiac output（CO）， and stroke volume（SV）. Serum levels of creatine kinase（CK）， CK-MB， triglyceride（TG）， total cholesterol（TC）， high-density lipoprotein cholesterol（HDL-C）， low-density lipoprotein cholesterol（LDL-C）， lactate dehydrogenase（LDH）， endothelin-1（ET-1）， endothelial nitric oxide synthase（eNOS）， tumor necrosis factor-α（TNF-α）， interleukin-18（IL-18）， oxidized LDL（ox-LDL）， and cardiac troponin T（cTnT） were measured by biochemical assays and enzyme-linked immunosorbent assay（ELISA）. Myocardial histopathology was evaluated via hematoxylin-eosin（HE） staining， while myocardial infarction and no-reflow area were assessed using 2，3，5-triphenyltetrazolium chloride（TTC）， Evans blue， and thioflavin staining. Changes in syndrome characteristics［body weight， tongue surface red-green-blue ［RGB］ values， and pulse amplitude］ of PBSBCS were recorded. Serum differential metabolites were analyzed by ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry（UPLC-Q-TOF-MS）. ResultsCompared with the sham operation group， the HFD and MIRI+HFD groups showed significant increases in body weight（P<0.01）， RGB values and pulse amplitude decreased in the HFD， MIRI and MIRI+HFD groups， TC， TG， LDL-C and ox-LDL levels increased in the HFD and MIRI+HFD groups， while HDL-C decreased. Blood perfusion peak time and myocardial no-reflow area increased， serum eNOS level decreased， and CK-MB， LDH， and cTnT activities increased in the HFD， MIRI and MIRI+HFD groups（P<0.05， P<0.01）. Whole blood viscosity was increased in the HFD group at medium shear rate， and in the MIRI and MIRI+HFD groups at low， medium and high shear rates（P<0.05， P<0.01）. Platelet aggregation rate increased in the MIRI and MIRI+HFD groups， accompanied by elevated ET-1， TNF-α， and IL-18 levels， reduced cardiac function indices， expanded myocardial no-reflow and infarction areas， and increased serum CK， CK-MB， LDH， and cTnT activities（P<0.05， P<0.01）. Compared with the MIRI group， the HFD and MIRI+HFD groups showed significant increase in body weight， TC， TG， LDL-C and ox-LDL levels， and significant decrease in HDL-C content（P<0.01）. The MIRI+HFD group showed decrease in RGB values and pulse amplitude， and an increase in whole blood viscosity， platelet aggregation， blood perfusion peak time， myocardial no-reflow and infarction areas， elevated ET-1， TNF-α and IL-18 levels， decreased eNOS content， EF and SV， increased serum CK， CK-MB and cTnT activities， and worsened myocardial pathology（P<0.05）. Compared with the HFD group， the MIRI+HFD group showed similar aggravated trends（P<0.05， P<0.01）. Metabolomics results showed that 34 potential biomarkers involving 13 common metabolic pathways were identified in the MIRI+HFD group compared with the sham operation group. ConclusionThe MIRI group resembles blood stasis syndrome in hemodynamics and myocardial injury， and the HFD group mirrors phlegm-turbidity syndrome in lipid profiles and tongue characteristics. While the MIRI+HFD group aligns with PBSBCS in comprehensive indices， effectively simulating clinical features of coronary heart disease（CHD）， which can be used for the evaluation of the pathological mechanism and pharmacodynamics of CHD with PBSBCS.

ObjectiveTo explore the feasibility， evaluation methods and metabolic differences of high-fat diet（HFD） combined with myocardial ischemia-reperfusion injury（MIRI） to establish a rat model of myocardial ischemia-reperfusion with phlegm and blood stasis blocking collaterals syndrome（PBSBCS）. MethodsThirty-two SD rats were randomly divided into the sham operation， HFD， MIRI， and MIRI+HFD groups. Rats in the sham operation and MIRI groups were fed a standard diet（regular chow）， while the HFD and MIRI+HFD groups received a HFD for 10 weeks. Rats in the MIRI and MIRI+HFD groups underwent myocardial ischemia-reperfusion surgery， while the sham operation group underwent only thread placement without ligation. Cardiac function was assessed via small-animal echocardiography， including left ventricular ejection fraction（EF）， left ventricular fractional shortening（FS）， cardiac output（CO）， and stroke volume（SV）. Serum levels of creatine kinase（CK）， CK-MB， triglyceride（TG）， total cholesterol（TC）， high-density lipoprotein cholesterol（HDL-C）， low-density lipoprotein cholesterol（LDL-C）， lactate dehydrogenase（LDH）， endothelin-1（ET-1）， endothelial nitric oxide synthase（eNOS）， tumor necrosis factor-α（TNF-α）， interleukin-18（IL-18）， oxidized LDL（ox-LDL）， and cardiac troponin T（cTnT） were measured by biochemical assays and enzyme-linked immunosorbent assay（ELISA）. Myocardial histopathology was evaluated via hematoxylin-eosin（HE） staining， while myocardial infarction and no-reflow area were assessed using 2，3，5-triphenyltetrazolium chloride（TTC）， Evans blue， and thioflavin staining. Changes in syndrome characteristics［body weight， tongue surface red-green-blue ［RGB］ values， and pulse amplitude］ of PBSBCS were recorded. Serum differential metabolites were analyzed by ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry（UPLC-Q-TOF-MS）. ResultsCompared with the sham operation group， the HFD and MIRI+HFD groups showed significant increases in body weight（P<0.01）， RGB values and pulse amplitude decreased in the HFD， MIRI and MIRI+HFD groups， TC， TG， LDL-C and ox-LDL levels increased in the HFD and MIRI+HFD groups， while HDL-C decreased. Blood perfusion peak time and myocardial no-reflow area increased， serum eNOS level decreased， and CK-MB， LDH， and cTnT activities increased in the HFD， MIRI and MIRI+HFD groups（P<0.05， P<0.01）. Whole blood viscosity was increased in the HFD group at medium shear rate， and in the MIRI and MIRI+HFD groups at low， medium and high shear rates（P<0.05， P<0.01）. Platelet aggregation rate increased in the MIRI and MIRI+HFD groups， accompanied by elevated ET-1， TNF-α， and IL-18 levels， reduced cardiac function indices， expanded myocardial no-reflow and infarction areas， and increased serum CK， CK-MB， LDH， and cTnT activities（P<0.05， P<0.01）. Compared with the MIRI group， the HFD and MIRI+HFD groups showed significant increase in body weight， TC， TG， LDL-C and ox-LDL levels， and significant decrease in HDL-C content（P<0.01）. The MIRI+HFD group showed decrease in RGB values and pulse amplitude， and an increase in whole blood viscosity， platelet aggregation， blood perfusion peak time， myocardial no-reflow and infarction areas， elevated ET-1， TNF-α and IL-18 levels， decreased eNOS content， EF and SV， increased serum CK， CK-MB and cTnT activities， and worsened myocardial pathology（P<0.05）. Compared with the HFD group， the MIRI+HFD group showed similar aggravated trends（P<0.05， P<0.01）. Metabolomics results showed that 34 potential biomarkers involving 13 common metabolic pathways were identified in the MIRI+HFD group compared with the sham operation group. ConclusionThe MIRI group resembles blood stasis syndrome in hemodynamics and myocardial injury， and the HFD group mirrors phlegm-turbidity syndrome in lipid profiles and tongue characteristics. While the MIRI+HFD group aligns with PBSBCS in comprehensive indices， effectively simulating clinical features of coronary heart disease（CHD）， which can be used for the evaluation of the pathological mechanism and pharmacodynamics of CHD with PBSBCS.

Objective:To evaluate the clinical value of different shimming methods at 7.0 T MR in two-dimensional (2D) and three-dimensional (3D) T 2WI. Methods:Totally 23 healthy volunteers were prospectively recruited from the First Medical Center of PLA General Hospital from November, 2022 to May, 2023, including 12 volunteers who underwent 2D shimming mode and 14 volunteers who underwent 3D shimming mode. 2D shimming mode included patient-specific (PS) mode, direct signal control (DSC) mode, the standard circularly polarized (CP) mode, and volume-specific (VS) mode. 3D shimming mode included universal pulses (UP) mode and CP mode. The image quality for the subtentorial and supratentorial region was assessed by the subjective image quality score and signal-to-noise ratio. Comparisons of quantitative indices between multiple groups were performed using repeated-measures ANOVA or Friedman′s test; comparisons of quantitative indices between 2 groups were performed using paired-samples t test or Wilcoxon signed-rank test. Results:The image quality of subtentorial region and SNR was significant differences in 2D T 2WI with PS mode, DSC mode, CP mode and VS mode ( F=26.74, P<0.001; F=28.24, P<0.001), and the image quality score and SNR of PS mode, DSC mode, VS mode were better than CP mode ( P<0.05). In 2D T 2WI, there was no significant difference in image quality score and SNR of supratentorial region in PS mode, DSC mode, CP mode ( P>0.05). Besides, in 3D T 2WI, the image quality score for subtentorial and supratentorial region of UP mode were better than those of CP mode ( Z=-2.74, P=0.006; Z=-3.24, P=0.001); SNR of subtentorial region was significantly better in UP mode than those in CP mode ( t=3.49, P=0.004). But there was no significant difference in SNR of supratentorial region between the UP mode and CP mode in 3D T 2WI ( P>0.05). Conclusion:T 2WI with different shimming methods at 7.0 T MR can provide data support for the clinical application, which is helpful for the accurate diagnosis of patients with subtentorial lesions.

Objective:To investigate the correlation between vascular wall characteristics and ischemic stroke and its mechanism in patients with atherosclerotic middle cerebral artery (MCA) stenosis.Methods:Patients with atherosclerotic MCA stenosis received high-resolution vessel wall imaging (HR-VWI) in Shenzhen Bao'an District People's Hospital from November 2017 to November 2018 were enrolled retrospectively. The imaging characteristics, such as the lumen and vessel diameter and vessel wall area at the narrowest level of MCA plaque, plaque load, remodeling index, and plaque enhancement rate were measured. A multivariate logistic regression model was used to identify the independent risk factors for stroke in patients with atherosclerotic MCA stenosis. Results:A total of 53 patients with atherosclerotic MCA stenosis were enrolled, aged (53.5±9.7) years, 28 were male (52.8 %). There were 28 in the stroke group and 25 in the non-stroke group. Thirteen patients were artery-artery embolization, 15 were non-artery-artery embolization; 39 were mild stenosis, and 14 were moderate to severe stenosis. Compared with the non-stroke group, the moderate to severe stenosis was more common in the stroke group ( P=0.010), the plaque load was greater ( P=0.006), and the remodeling index was lower ( P=0.010). Multivariate logistic regression analysis showed that the remodeling index was an independent risk factor for stroke in patients with atherosclerotic MCA stenosis (odds ratio 0.002, 95% confidence interval 0.000-0.952; P=0.048). Compared with the non-artery-artery embolization group, the mean thickness of MCA was larger in the artery-artery embolization group ( P=0.037). Compared with the mild stenosis group, the plaque load was greater ( P=0.001), the plaque enhancement rate was higher ( P=0.004), and remodeling index was lower ( P<0.001) in the moderate to severe MCA stenosis group. Conclusions:In the atherosclerotic MCA stroke group, patients with moderate to severe stenosis are more common, with greater plaque load and lower remodeling index. Remodeling index is an independent risk factor for ischemic stroke. Patients with moderate to severe MCA stenosis have a higher plaque enhancement rate and a lower remodeling index, suggesting that the vessel wall inflammatory response is more significant and had decompensation. HR-VWI is expected to be used to assess the pathogenesis of ischemic stroke events.

OBJECTIVE: To investigate the effect of 1,2-dichloroethane(1,2-DCE) acute inhalation exposure on the differential gene expression of phase Ⅰ metabolic enzymes. METHODS: The specific pathogen free SD rats were randomly divided into control group(16 rats), low-and high-dose groups(24 rats in each group, half males and half females). Low-and high-dose group were given daily 600, 1 800 mg/m~(3 ) of 1,2-DCE, and the control group given the fresh air by dynamic inhalation for 8 hours per day for consecutive 7 days. After the end of exposure, the relative mRNA expression of cytochrome P450 2 E1(CYP2 E1), alcohol dehydrogenase(ADH1) and acetaldehyde dehydrogenase 3 alpha 1(ALDH3α1) in the liver tissue was detected by real-time fluorescence quantitative polymerase chain reaction. RESULTS: The relative expression of CYP2 E1 in male high-dose group was higher than that in male low-dose group and female high-dose group(P<0.05). The relative expression of ADH1 in male low-and high-dose groups was higher than that in male control group(P<0.05). The relative expression of ADH1 in male high-dose group was higher than that in male low-dose group and female high-dose group(P<0.05). The relative expression of ALDH3α1 in high-dose group was higher than that in control group and low-dose group(P<0.05). CONCLUSION: High dose 1,2-DCE could increase the gene expression of phase Ⅰ metabolic enzymes in rat liver. The 1,2-DCE has more obvious effect in male rats than in female rats.

OBJECTIVE: To investigate the evaluation value of preoperative peripheral blood lymphocyte-to-monocyte ratio (LMR) on the prognosis of patients with stage III colon cancer undergoing radical resection and postoperative adjuvant chemotherapy. METHODS: Electronic medical record were retrospectively retrived for stage III colon cancer patients who underwent radical surgery at Sun Yat-sen University Cancer Center from December 2007 to December 2013. Inclusion criteria were pathologically comfirmed colon adenocarcinoma, complete clinicopathological data, and postoperative XELOX (oxaliplatin + capecitabine) chemotherapy with follow-up of at least 3 months. Patients with neoadjuvant anti-tumor therapy, infectious disease, other malignant tumors and death of non-tumor causes within 3 months after operation were excluded. A total of 258 patients were included in this retrospective cohort study, including 146 males and 112 females with median age of 55 (22 to 85) years. Tumors of 100(38.8%) patients were located in the right hemicolon, and of 158 (61.2%) in the left hemicolon. Tumors of 194(75.2%) patients were highly and moderately differentiated, and of 64 (24.8%) were poorly differentiated. According to the TNM tumor pathological stage of AJCC 7th edition, 196 (76.0%) patients were stage IIIA to IIIB, and 62(24.0%) patients were stage IIIC. The median preoperative CEA was 3.8 (0.3 to 287.5) μg /L and the median cycle of the adjuvant chemotherapy was 6 (1 to 8). The cut-off value of preoperative LMR in prediction of 3-year overall survival (OS) outcome was determined by receiver operating characteristic (ROC) curve analysis. All patients were divided into low LMR group and high LMR group according to the critical value. Clinicopathological characteristics between the two groups were compared by using chi-square test or Fisher's exact test as appropriate. The 3-year disease-free survival and overall survival rate were estimated with the Kaplan-Meier method, and differences between two groups were assessed with the log-rank test. Univariate and multivariate analyses were performed through Cox regression model. RESULTS: ROC curve showed that the cut-off value of preoperative LMR in predicting 3-year overall survival was 4.29. Then 143 patients were divided into low LMR group (LMR<4.29) and 115 patients into high LMR group (LMR ≥ 4.29). Compared with high LMR group, the low LMR group presented higher proportions of male [62.2%(89/143) vs. 50.4%(58/115), χ²=4.167, P=0.041], right hemicolon cancer [44.8% (64/143) vs. 31.3% (36/115), χ²=4.858, P=0.028], and the largest tumor diameter>4 cm [60.1% (86/143) vs. 33.0% (38/115), χ²=18.748, P<0.001]. During a median follow-up of 46.0 (range, 3.0 to 74.0) months, 3-year disease-free survival rate was 83.8% in high LMR group and 78.9% in low LMR group, which was not significantly different (P=0.210). While 3-year overall survival rate in low LMR group was significant lower than that in high LMR group (86.6% vs. 97.2%, P=0.018). Univariate analysis revealed that preoperative low LMR (HR=2.841, 95%CI: 1.146 to 7.043, P=0.024), right hemicolon cancer (HR=2.865, 95%CI: 1.312 to 6.258, P=0.008) and postoperative adjuvant chemotherapy≥6 cycles (HR=0.420, 95%CI: 0.188 to 0.935, P=0.034) were the risk factors for poor overall survival. Multivariate analysis identified that preoperative low LMR (HR=2.550, 95%CI: 1.024 to 6.347, P=0.004) and right hemicolon cancer (HR=2.611, 95%CI: 1.191 to 5.723, P=0.017) were the independent risk factors for overall survival. CONCLUSIONS Preoperative peripheral blood LMR level represents an effective prognostic predictor for patients with stage III colon cancer receiving radical therapy. Low LMR indicates the poor prognosis and such patients require aggressive postoperative treatment strategy.
Adenocarcinoma ; blood ; drug therapy ; surgery ; Adult ; Aged ; Aged, 80 and over ; Antineoplastic Combined Chemotherapy Protocols ; administration & dosage ; Chemotherapy, Adjuvant ; Colonic Neoplasms ; blood ; drug therapy ; surgery ; therapy ; Female ; Humans ; Kaplan-Meier Estimate ; Leukocyte Count ; methods ; Lymphocytes ; Male ; Middle Aged ; Monocytes ; Preoperative Care ; Prognosis ; Retrospective Studies ; Young Adult

OBJECTIVETo investigate the feasibility of endoscopic metallic stent as a bridge to elective laparoscopic surgery in patients with malignant colorectal obstruction.

METHODSClinical data of 63 patients with obstructive colorectal cancer who underwent endoscopic metallic stent insertion under radiologic monitoring at the Longyan First Hospital between June 2012 and August 2016 were analyzed retrospectively. After complete remission of the obstruction, all the patients received multi-disciplinary team (MDT) evaluation to make the further treatment strategy. The subsequent surgery included open and laparoscopic procedures, and the short-term efficacy of these two procedures was compared.

RESULTSThere were 30 male and 33 female patients with age of 30 to 90 (mean 67) years, including 3 cases of ascending colon cancer, 4 cases of transverse colon cancer, 12 cases of descending colon cancer, 26 cases of sigmoid cancer, and 19 cases of rectal cancer. Only one patient (1.6%) developed sigmoid perforation at 3 hours after stent placement, and underwent emergency laparotomy with Hartmann procedure. The remaining 62 patients had bowel movements. After MDT evaluation, 10 patients (16.1%) were treated with palliative chemotherapy because they were unfit for surgery or for diffuse distant metastases. A total of 52 patients underwent radical surgery after a mean interval from stent insertion of 10 days (7-20 days), including open (n=18, including two cases with conversion to open surgery) and laparoscopy (n=34). The baseline data between open and laparoscopy groups were similar (all P>0.05). Primary anastomosis was successfully performed in all the patients without preventive stoma. Compared to open group, laparoscopy group had faster bowel movement [(2.88±1.06) d vs. (4.05±2.43) d, P=0.022] and shorter postoperative hospital stay [(7.85±0.96) d vs. (9.82±4.41) d, P=0.002]. There were no statistically significant differences in operative time, intraoperative blood loss, number of harvested lymph node, and postoperative complication rate between two groups (all P>0.05).

CONCLUSIONSEndoscopic metallic stent placement can effectively remove malignant colorectal obstruction, and thus enables surgeons to perform an elective radical surgery, avoiding emergency surgery with stoma and unnecessary surgery for patients with distant metastasis. In the era of enhanced recovery after surgery, the endoscopic metallic stent placement combined with laparoscopic procedures, as a less invasive alternative, is effective and safe.

Objective To evaluate the application value of different MR sequences in cerebral developmental venous anomalies (DAVs),and to explore the relationship between DVAs and its associated lesions.Methods MRI findings in 38 patients of DAVs were analyzed retrospectively.Imaging performance and characteristics of DAVs and its associated lesions in different MR sequences were analyzed.Results In all of the 38 cases,3 cases were multiple DVAs without associated lesions,1 case was combined right lateral ventricle hemorhage,1 case was combined with multiple cavernous hemangioma,8 cases were single DVAs with solitary cavernous hemangioma,5 cases were combined with astrocytoma,1 case was combined with intracranial hematoma,and 19 cases were single DVAs with no comorbidity.DVAs in 16 cases showed strip or small patchy hypo-intensity lesions and 15 cases were not visible on T1WI;16 cases showed strip or small patchy hypo-intensity,5 cases showed strip or flocculent hypo-intensity and 10 cases could not seen on T2WI;19 cases showed patchy or strip hypo-intensity and 8 cases showed iso intensive signal on DWI;8 of the 10 cases who performed susceptibility weighted imaging (SWI) examination showed dendritic low signal,showing a typical caput medusae sign,2 cases showed no lesions on SWI;30 cases underwent 3D-T1WI enhanced scan showed clearly all lesions of DAVs,19 cases of them showed typical caput medusae sign and large draining veins.Conclusion Routine MR sequence can demonstrate part of the DVAs and associated peripheral lesions,DWI showed lesions of DAVs is superior to routine MR sequence,SWI and enhanced 3D-T1WI can accurately diagnose DVAs and show the venous drainage.

Objective To observe the influence of Huiyang Shengji Ointment and its modified formulae on interleukin-1 (IL-1α) and thromboxane B2 (TXB2) in diabetic rats with chronic skin ulcers, and explore the mechanism for promoting the healing of ulcer.Methods Six out of 160 rats were randomly selected as a blank group, without any further processing. The remaining rats were made diabetic model and randomly divided into five groups after 2 weeks:1 d, 3 d, 5 d, 7 d and 14 d groups. Then, these groups were further divided into normal group (Vaseline ointments), model group (Vaseline ointments), Huiyang Shengji Ointment group (whole formula Ointment), Wenyang Yiqi group (Yiqi group, modified Wenyang Yiqi formula ointments) and Huoxue Shengji group (Huoxue group, modified Huoxue Shengji formula ointments). Normal group and model group were given Vaseline ointments;whole formula group, Yiqi group and Huoxue group were given corresponding ointment. Normal group used the method of skin excision, while other groups used STZ injection-hydrocortisone interference-skin excision-foreign body embedded preparation of composite factors for chronic skin ulcer model. After the appropriate treatment period, the rats were executed and tested for the contents of IL-1α and TXB2 in serum by enzyme-linked immunosorbent assay of five time points.Results In treatment 3 d, the contents of IL-1α in Yiqi group were significantly higher than the blank group, model group, whole formula group and Huoxue group (P<0.05). In treatment 5 d, the contents of IL-1α in whole formula group were significantly higher than the blank group and model group (P<0.05). In treatment 7 d, the contents of IL-1α in each treatment group were significantly higher than blank group and model group (P<0.05), and the whole formula group was higher than the Yiqi group and Huoxue group. In treatment 14 d, the contents of IL-1α in model group and Huoxue group were lower than the blank group (P<0.05). In treatment 3 d, the contents of TXB2 in normal group and the whole formula group were higher than the blank group (P<0.05). In treatment 5 d, the contents of TXB2 in whole formula group were higher than the blank group and the normal group (P<0.05). In treatment 7 d, the contents of TXB2 in Yiqi group were higher than the blank, the model, the whole formula and Huoxue groups (P<0.05). In treatment 14 d, the contents of TXB2 in Huoxue group were higher than the blank and model group (P<0.05), and the contents of TXB2 in the blank group and normal group was lower than those treatment groups (P<0.05).Conclusion Huiyang Shengji Ointment and its modified formulae could promote inflammation, stimulate secretion of inflammatory cytokines, while Yiqi Wenyang ointments played a more active role in promoting inflammation of the early phase of wound surface.

Avian influenza A virus continues to pose a global threat with occasional H5N1 human infections, which is emphasized by a recent severe human infection caused by avian-origin H7N9 in China. Luckily these viruses do not transmit efficiently in human populations. With a few amino acid substitutions of the hemagglutinin H5 protein in the laboratory, two H5 mutants have been shown to obtain an air-borne transmission in a mammalian ferret model. Here in this study one of the mutant H5 proteins developed by Kawaoka's group (VN1203mut) was expressed in a baculovirus system and its receptor-binding properties were assessed. We herein show that the VN1203mut had a dramatically reduced binding affinity for the avian α2,3-linkage receptor compared to wild type but showed no detectable increase in affinity for the human α2,6-linkage receptor, using Surface Plasmon Resonance techonology. Further, the crystal structures of the VN1203mut and its complexes with either human or avian receptors demonstrate that the VN1203mut binds the human receptor in the same binding manner (cis conformation) as seen for the HAs of previously reported 1957 and 1968 pandemic influenza viruses. Our receptor binding and crystallographic data shown here further confirm that the ability to bind the avian receptor has to decrease for a higher human receptor binding affinity. As the Q226L substitution is shown important for obtaining human receptor binding, we suspect that the newly emerged H7N9 binds human receptor as H7 has a Q226L substitution.
Air Microbiology ; Crystallography, X-Ray ; Glycosylation ; Hemagglutinin Glycoproteins, Influenza Virus ; chemistry ; genetics ; metabolism ; Humans ; Influenza A Virus, H5N1 Subtype ; chemistry ; metabolism ; Influenza A Virus, H7N9 Subtype ; chemistry ; Models, Molecular ; Mutant Proteins ; chemistry ; genetics ; metabolism ; Protein Binding ; Protein Stability ; Receptors, Cell Surface ; genetics ; metabolism ; Solubility ; Surface Plasmon Resonance ; Temperature