Efficacy and Safety of Mulberry Twig Alkaloids Tablet for Treatment of Type 2 Diabetes: A Randomized, Double-Blind, Placebo-Controlled Multicenter Clinical Study / 中国结合医学杂志

OBJECTIVE@#To assess the efficacy and safety of mulberry twig alkaloids (Sangzhi alkaloids, SZ-A) for treatment of type 2 diabetes in a randomized, double-blind, placebo-controlled multicenter clinical trial.@*METHODS@#A total of 200 patients were randomized to receive SZ-A (n=100) or placebo (n=100) for 16 weeks. The data analysis system for electronic data capture clinical trial central randomization system was used for randomization and dispensing of drugs. The primary outcome was the change in glycosylated hemoglobin (HbA1c) level. The secondary outcome included the proportions of cases with HbA1c <7.0% and HbA1c <6.5%, fasting blood glucose (FBG), postprandial blood glucose (PBG), area under curve for the PBG (AUC0-2h), body weight, and body mass index (BMI). Adverse events (AEs), severe adverse events (SAEs), treatment-related adverse events (TAEs), gastrointestinal disorders (GDs), blood pressure, routine blood tests, and liver and kidney function were monitored.@*RESULTS@#Compared with baseline, the change of HbA1c at week 16 was -0.80% (95% CI: -0.98% to -0.62%) and -0.09% (95% CI: -0.27% to 0.09%) in SZ-A group and placebo group, respectively. The proportion of patients with HbA1c <7% and <6.5% was higher in the SZ-A group than in the placebo group (46.8% vs. 21.6% and 29.9% vs. 10.8%). The observed values and changes in FBG, 1 h-PBG, 2 h-PBG, and AUC0-2h differed significantly between groups (P<0.001), but differences were not significant in body weight and BMI (P>0.05). The incidence rates of AEs, TAEs, and GDs differed significantly between groups (P=0.010, P=0.005, and P=0.006, respectively), whereas the incidence rates of SAEs showed no significant differences between groups (P=1.000).@*CONCLUSION@#SZ-A are effective and safe for treatment of type 2 diabetes. The protocol was registered in http://www.chictr.org.cn/showproj.aspx?proj=60117 (ChiCTR2000038550).

Retinal displacement after closure of idiopathic macular hole

Objective:To study the foveal displacement during the closure of idiopathic macular holes (MHs).Methods:Thirty-seven idiopathic MH patients treated by pars plana vitrectomy and internal limiting membrane peeling were studied prospectively. Locations of MH center and foveal pit were measured by optic coherence tomography. Retinal displacement was observed using confocal scanning laser ophthalmoscopy.Results:A total of 40 eyes were included in this study and MHs were closed in 37 eyes (92.5%). The confocal scanning laser ophthalmoscopy showed that all of the retinal capillaries in the superior, inferior, nasal and temporal sides of the MHs moved toward the optic nerve head (ONH). The optic coherence tomography results showed that the mean nasal displacements of foveal pits were (102.9±61.2), (109.6±53.1), and (137.0±52.0) μm at 3, 6 and 12 months, respectively. And the mean vertical displacements were (55.9±49.4), (61.4±57.8) and (67.8±54.3) μm, respectively. Post-operative foveal pits were located in the nasal side of the MH centers. The extension of retina and nasal to the MH were in opposite directions: the nasal hole margin moved toward the MH, but the retina located closer to the ONH moved toward the ONH. The fellow eyes of three patients developed into idiopathic MH during the follow-up period and operations were performed for all of the three patients.Conclusion:Our results showed that center of macula does not move when an idiopathic MH develops, but it moves toward ONH during closure of hole; thus, new fovea is in nasal side of original fovea.

Retinal displacement after closure of idiopathic macular hole

Objective: To study the foveal displacement during the closure of idiopathic macular holes (MHs). Methods: Thirty-seven idiopathic MH patients treated by pars plana vitrectomy and internal limiting membrane peeling were studied prospectively. Locations of MH center and foveal pit were measured by optic coherence tomography. Retinal displacement was observed using confocal scanning laser ophthalmoscopy. Results: A total of 40 eyes were included in this study and MHs were closed in 37 eyes (92.5%). The confocal scanning laser ophthalmoscopy showed that all of the retinal capillaries in the superior, inferior, nasal and temporal sides of the MHs moved toward the optic nerve head (ONH). The optic coherence tomography results showed that the mean nasal displacements of foveal pits were (102.9±61.2), (109.6±53.1), and (137.0±52.0) μm at 3, 6 and 12 months, respectively. And the mean vertical displacements were (55.9±49.4), (61.4±57.8) and (67.8±54.3) μm, respectively. Post-operative foveal pits were located in the nasal side of the MH centers. The extension of retina and nasal to the MH were in opposite directions: the nasal hole margin moved toward the MH, but the retina located closer to the ONH moved toward the ONH. The fellow eyes of three patients developed into idiopathic MH during the follow-up period and operations were performed for all of the three patients. Conclusion: Our results showed that center of macula does not move when an idiopathic MH develops, but it moves toward ONH during closure of hole; thus, new fovea is in nasal side of original fovea.

Port-Site Metastases and Chimney Effect of B-Ultrasound-Guided and Laparoscopically-Assisted Hyperthermic Intraperitoneal Perfusion Chemotherapy

PURPOSE: CO₂ leakage along the trocar (chimney effect) has been proposed to be an important factor underlying port-site metastasis after laparoscopic surgery. This study aimed to test this hypothesis by comparing the incidence of port-site metastasis between B-ultrasound-guided and laparoscopically-assisted hyperthermic intraperitoneal perfusion chemotherapy (HIPPC). MATERIALS AND METHODS: Sixty-two patients with malignant ascites induced by gastrointestinal or ovarian cancer were divided into two groups to receive either B-ultrasound-guided or laparoscopically-assisted HIPPC. Clinical efficacy was assessed from the objective remission rate (ORR), the Karnofsky Performance Status (KPS) score, and overall survival. The incidence of port-site metastasis was compared between the two groups. RESULTS: Patients in the B-ultrasound (n=32) and laparoscopy (n=30) groups were comparable in terms of age, sex, primary disease type, volume of ascites, and free cancer cell (FCC)-positive ascites. After HIPPC, there were no significant differences between the B-ultrasound and laparoscopy groups in the KPS score change, ORR, and median survival time. The incidence of port-site metastasis after HIPPC was not significantly different between the B-ultrasound (3 of 32, 9.36%) and laparoscopy (3 of 30, 10%) groups, but significantly different among pancreatic, gastric, ovarian, and colorectal cancer (33.33, 15.79, 10.00, and 0.00%, p<0.001). CONCLUSION: The chimney effect may not be the key reason for port-site metastasis after laparoscopy. Other factors may play a role, including the local microenvironment at the trocar site and the delivery of viable FCCs (from the tumor or malignant ascites) to the trauma site during laparoscopic surgery.

The effect of ischemic precondition to IL-6 on rat liver ischemia-reperfusion injury in transplantation

OBJECTIVE@#To investigate the effect of ischemic precondition to protect ischemia-reperfusion injury and reduce IL-6 expression in the rats liver transplantation.@*METHODS@#The rat portal vein infusion of autologous liver transplantation model were used. The rats were divided into ischemic preconditioning rats liver transplantation group (A group), the rats liver transplantation group (B group) and the normal rat control group (C group). Then we analyzed the changes of liver function, liver microstructure and the expression of IL-6, SOD and MDA within 48 h.@*RESULTS@#The pathology of liver in group A showed lobular architecture essentially normal, the liver cells was slightly swell and no significant changes in postoperative 12 h. In transmission electron microscope (46 000×), the mitochondria of liver cells in group A became swelling, elliptical can cristae partially broken. But there still has a small amount of arrangement. While that in group, the mitochondria were swollen, became round, serious visible crest reduce or ruptured. The result of over function test showed that the serum ALT and AST levels in group A and B were both higher than that in group C at each time period, but the serum ALT and AST levels in group A were lower than that in group B. The expression changes of IL-6 in group B were higher than that in group A and B (P<0.05). The expression of MDA in group A is more obvious than that in group B (P<0.05)@*CONCLUSIONS@#Ischemic precondition could alleviate part of ischemia-reperfusion injury in the rat liver transplantation, and also could reduce IL-6 expression to protect the liver cells against liver damage and inflammatory cytokine production.

Epidemiological analysis of the human plague from 2001 to 2011 in Qinghai Province / 中国地方病学杂志

Objective To analyze human plague from 2001 to 2011 in Qinghai Province and to provide a scientific basis for formulating prevention and control measures.Methods Using the descriptive epidemiological methods,epidemiological field survey data and medical records of each case of human plague were collected from 2001 to 2011 in Qinghai Province.Human plague was judged in accordance with the Plague Diagnostic Criteria (WS 279-2008).Results From 2001 to 2011,human plague was reported 14 times,with incidence of 38 cases,17 dead and death rate was 44.74％ in Qinghai Province.Epidemic areas mainly distributed in the 12 townships of 9 counties.Prevalent season was from May to October,September and October accounted for 57.89％ (22/38).There were cases of Tibetan herders and Han farmers,accounting for 76.32％ (29/38) and 23.68％ (9/38),respectively;onset age from 5 to 67 years,mainly around the age of 20-45 [68.42％ (26/38)].The most prevalent clinical types were pneumonic and septicemic plague and initial case was caused by actively contact with infected plague animals.Conclusions Qinghai human plague is mainly caused by approaching the plague infected animals,human plague in Qinghai Province is on the rise,the risk of long-distance transmission of the plague is significantly increased.

Effect of expression of c-jun N-terminal kinase on neuron autophagy following diffuse brain injury in rats / 中华外科杂志

<p><b>OBJECTIVE</b>To study the effect and potential mechanism of expression of c-jun N-terminal kinase (JNK) signal pathway on neuron autophagy after diffuse brain injury (DBI).</p><p><b>METHODS</b>Male Sprague Dawley rats (n = 216) were randomly divided into four groups: DBI group (n = 54), SP600125 intervene group (n = 54), DMSO group (n = 54) and sham operation group (n = 54). DBI rat model was established according to the description of Marmarou DBI. At different time points (1, 6, 12, 24, 48 and 72 h) after operation, the histopathologic changes of neurons in cortex were observed by HE staining method; The expression of p-JNK, p-P53, DRAM and Beclin-1 were detected by Western blot and immunohistochemistry.</p><p><b>RESULTS</b>The results showed that under light microscope degenerated and necrotic neurons were observed to be scattered in cortex at 6 h after operation in DBI group, but these changes were low in SP600125 intervene group. Compared with SP600125 intervene group, the expression of p-JNK in DBI group were enhanced obviously at 6, 12 and 24 h (F = 17.902, P < 0.05); the expression of p-P53 in DBI group were enhanced obviously at 12, 24, 48 and 72 h (F = 7.107, P < 0.05); the expression of DRAM in DBI group were enhanced obviously at 6, 12, 24, 48 and 72 h (F = 15.455, P < 0.05); the expression of Beclin-1 in DBI group were enhanced obviously at 6, 12, 24, 48 and 72 h (F = 11.517, P < 0.05). Compared with DBI group, the expression of p-JNK, p-P53, DRAM and Beclin-1 in DMSO group were similar at 1, 6, 12, 24, 48 and 72 h (F = 1.509, P > 0.05).</p><p><b>CONCLUSIONS</b>The present results indicate that SP600125 can dramatically improve trauma brain injury from autophagy after DBI and the molecular mechanism is related to the modulation of JNK signal pathway following DBI, while it measures the neuron autophagy by means of intervening JNK signal pathway.</p>

Predicting value of serum CEA and CA19-9 in neoadjuvant chemotherapy for advanced gastric carcinoma / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the predictive value of CEA and CA19-9 in tumor progression, prognosis and neoadjuvant chemotherapy of advanced gastric cancer.</p><p><b>METHODS</b>Clinical data of 322 patients with advanced gastric cancer(54 cases undergoing neoadjuvant chemotherapy) from the Affiliated Oncologic Hospital of Guangzhou Medical College were reviewed. Serum CEA and CA19-9 levels were detected by electrochemiluminescence immunoassay, while the expression of CEA and CA19-9 protein in 54 pairs of tumor tissues and matched biopsies neoadjuvant chemotherapy were determined by immunohistochemistry.</p><p><b>RESULTS</b>The expression levels of serum CEA and CA19-9 were closely related to tumor invasion, lymph node metastasis and TNM stage(all P<0.05). The 5-year cumulative survival rates of patients with serum CEA-positive and CA19-9-positive were 17.0% and 11.9%, compared with 34.6% and 34.8% of the patients with serum CEA-negative and CA19-9-negative respectively (both P<0.05). Neoadjuvant chemotherapy could down-regulate CEA and CA19-9 expressions in tumor tissues(P<0.05), while there was no significantly difference in serum level(P>0.05).</p><p><b>CONCLUSIONS</b>The expressions of serum CEA and CA19-9 are closely associated with tumor progression and prognosis in advanced gastric cancer. However, further study should be done to evaluate their value in selecting patients to receive neoadjuvant chemotherapy.</p>

Influence of antibody-mediated immune pressure on neuraminidase gene mutations of avian influenza virus H9N2 / 病毒学报

LG1 strain of avian influenza virus H9N2 was passaged continuously for 40 generations in chicken embryos with anti-LG1 maternal antibodies in 4 parallel experiments, of which 3 experiments had a stable mutation of "G" to "A" at #99 of the neuraminidase gene(NA)from the 20th passage resulting in a change of Met to Ile and 2 had a stable mutation of "A" to "G" at #473 of the NA gene from the 30th passage resulting in a change of Asn to Ser which occurred in the 50th passage of another experiment. Eighty continuous passages in chicken embryos without antibody did not have the same mutation, indicating that the mutations of the 2 positions were associated with selective pressure of antibodies. Analysis of the ratios of nonsynonium (NS) vs synonium (S) mutations of nucleic acids demonstrated that NS/S of 4 parallel experiments with antibodies was 4.6 (32/7) compared with 2.0 (16/8) of the 2 experiments without antibodies and this significant difference implied the selective pressure of antibodies.

Antigenic comparative analysis of Newcastle disease viruses with evolutional mutations in HN and F genes under antibody immune pressures / 病毒学报

In chicken fibroblast cell (CEF) cultures with antiserum against Newcastle disease virus (NDV) strain TZ060107, the virus was passed serially for 50 passages in 3 independent lineages. HN and F genes were amplified and sequenced every 10 passages. The derived virus A1-50 with most mutations among 3 lineages was further passed for another 50 passages in CEF with or without antiserum against A1-50, each in 3 independent lineages. Sequence comparisons for HN and F genes of 60, 70, 80, 90 and 100 passages indicated that the ratio of nonsynonymous mutations (NS) vs synonymous mutations (S) for HN genes in the lineages passed with antiserum against A1-50 was 5.25, which was obviously higher than 2. 375 of NS/ S in the lineages without the antiserum. The stable NS mutations occurred in the first 50 passages with the antiserum against the original TZ060107 were still maintained and one more new stable NS mutation appeared. For the F gene, 3 new stable NS mutations occurred during the second 50 passages in lineages with antiserum against A1-50 when the original NS mutations obtained in the first 50 passages with antiserum against TZ060107 still existed. Cross hemagglutination inhibition (HI) between original virus and its derivative viruses indicated that the more continuous passages in cell culture with antiserum passed, the bigger difference of antigenicity between the virus and the original virus had.

Identification of a new subgroup of avian leukosis virus isolated from Chinese indigenous chicken breeds / 病毒学报

In order to clarify Avian leukosis virus (ALV) characteristics from Chinese native chicken breeds, three ALV JS11C1, JS11C2 and JS11C3 were isolated from Chinese native breed "luhua" by inoculation of DF1 cell culture and detection of p27 antigen. Using PCR amplification of env gene, the amplified gp85 genes were analyzed and compared to all six chicken ALV subgroups reported. The gp85 genes of these three viruses were 1 005bp in length and encoded 335 amino acids, and the gp37 genes were 609bp and encoded 203 amino acids. The homology of gp85 among these three isolated strains was 91.9%-97.0%. Comparing to 18 stains of subgroup A, B, C, D, E published in GenBank, the homology was only in the range of 77.7%-84.6%, significantly lower than the gp85 homology observed within the common chicken subgroups A (88.2%-98.5%), B (91.6%-98.8%), and E (97.9%-99.4%). The gp85 homology compared with subgroup J was only 34.2%-36.5%. These results suggested that three isolated strains from Chinese native breed "luhua" belong to a new subgroup different from all six known subgroups from Chickens, and thus designated as subgroup K.

The ALV-A/B specific antibodies correlation between ELISA and IFA detection in chicken serum / 病毒学报

To study the correlation between ELISA and IFA tests in detection of ALV-A/B antibody in chicken sera, ELSA S/P values and IFA titers for different serum samples were measured and statistically analyzed. The results indicated that there was a strong positive correlation between ELISA S/P values and IFA titers (r = 0.97435, P < 0.001). Because the positive correlation between ELISA and IFA was so strong and antibody positive rates were identical in two tests, it suggested that IFA could be used as a alternative method to replace ELISA kit when only limited numbers of samples to be tested to reduce the cost and increase the sensitivity.

Effect of c-Jun NH₂-terminal kinase-mediated p53 expression on neuron autophagy following traumatic brain injury in rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Activation of c-Jun NH(2)-terminal kinase (JNK) has been implicated in neuron apoptosis as well as autophagy in response to various stressors after traumatic brain injury (TBI). However, the underlying molecular pathway remains unclear. Our study assessed whether JNK-mediated p53 phosphorylation might be an important mechanism for enhancing neuron autophagy in response to TBI.</p><p><b>METHODS</b>A total of 186 male Sprague-Dawley (SD) rats (300 - 350 g) were used in this study. By randomized block method rats were randomly divided into four groups: sham-operated (n = 46), TBI (n = 60), TBI + dimethyl sulfoxide (DMSO) (n = 40), and TBI + SP600125 (n = 40). JNK was treated with SP600125, a specific JNK inhibitor. JNK, p-P53, Beclin-1, damage-regulated autophagy modulator (DRAM) and p-bcl-2 were evaluated by Western blotting analysis. The cellular localization and expression of Beclin-1 and DRAM was observed by immunofluorescence and immunohistochemistry, and the expression of Beclin-1-Bcl-2/Bcl-xL complexes was evaluated by immunoprecipitation. Multiple-group comparisons were conducted using analysis of variance (ANOVA). P values of less than 0.05 were considered statistically significant.</p><p><b>RESULTS</b>It was observed that the expression of JNK, p-P53, Beclin-1, DRAM and p-bcl-2 was increasing after TBI, and the expression of Beclin-1 and DRAM was mainly located in the cytoplasm of neurons. But these were significantly inhibited in SP600125 group compared with sham group and TBI + SP600125 group (P < 0.05). The expression of Beclin-1-Bcl-2/Bcl-xL complexes was reduced after TBI.</p><p><b>CONCLUSION</b>JNK-mediated p53 phosphorylation might be an important mechanism for enhancing neuron autophagy in response to TBI.</p>

Endovascular treatment of intracranial aneurysms using coil embolization plus an Enterprise stent / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Several difficulties can arise from wide-neck cerebral aneurysms when treated with endovascular embolization. We aimed to investigate the effect of endovascular treatment of intracranial aneurysms using coil embolization plus an Enterprise stent.</p><p><b>METHODS</b>Forty patients were treated with coil embolization plus an Enterprise stent between December 2008 and June 2010.</p><p><b>RESULTS</b>The mortality of patients was 0. All stents were successfully implanted without any surgery-related complication.</p><p><b>CONCLUSION</b>The Enterprise stent has some advantages to be selected.</p>

Literature review of the efficacy and safety of hyperthermic intraperitoneal perfusion chemotherapy after cytoreductive surgery in the treatment of pseudomyxoma peritonei / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To evaluated the safety and efficacy of hyperthermic intraperitoneal perfusion chemotherapy(HIPC) in the prevention and treatment of pseudomyxoma peritonei (PMP) recurrence after cytoreductive surgery(CRS).</p><p><b>METHODS</b>Studies published in English before 2010 on HIPC after CRS for PMP were searched in PubMed database. Each study was carefully evaluated based on pre-determined criteria. Study results were comprehensively displayed in a form. A descriptive systematic review was performed.</p><p><b>RESULTS</b>A total of 11 studies were included. The median survival time of patients in these studies ranged from 25.6 months to 156 months. The ranges of 1-year, 2-year, 3-year, 5-year, and 10-year survival rates were 72%-100%, 55%-96%, 59%-96%, 52%-96%, and 55%-96%, respectively. The overall complication rate ranged from 2%-15%, and the total perioperative mortality were from 0 to 7%.</p><p><b>CONCLUSION</b>HIPC after CRS is effective and safe for patients with PMP.</p>

Comparison of whole genome sequences and replication ability in cell cultures between two avian leukosis viruses of subgroup B / 病毒学报

The purpose of this study was to compare the whole genome sequences and replication dynamics in cell cultures of two Avian leukosis viruses of subgroup B (ALV) isolates, SDAU09E3 and SDAU09C2. Comparison of the amino acid sequences indicated that the gp85 identity of these two subgroup B isolates was 95.4%, the identity with other three ALV-B reference strains was 91.0%-94.9%, and less than 87.9% with ALV subgroup A, C, D, E and J. Comparison of the nucleotide sequence of gag and pol genes indicated that homologies of gag gene and pol gene of these two ALV-B isolates with all compared reference strains of different subgroups were above 93%. Homologies of LTR sequence of these two ALV-B isolates with other exogenous ALVs subgroups A, B, C, D and J were 72.6%-88.3%, but only 51.5% when compared with endogenous ALV subgroup E. The identity of LTR between these two ALV-B strains was only 74.8%, which was far lower than the identity of other genes. The identity of U3 region of LTR between these two ALV-B isolates was only 68.8% and there were obvious differences in the number CAAT Boxes. Replication dynamics in DF-1 cell indicated that the value of TCID50 was similar between 2 isolates but the concentration of nucleocapsid protein p27 antigen of SDAU09E3 was significantly higher than SDAU09C2 in cell culture supernatant, which indicated there was no parallel relationship between p27 antigen concentration and infectious virus particles. Whether such difference was resulted from the diversity of U3 region of LTR, further studies with their recombinant infectious clones is necessary.

Correlation between TCID50 and p27 antigen of avian leukosis virus subgroup J / 病毒学报

To study the correlation between 50% tissue-culture infective dose (TCID50) value and p27 antigen S/P value of Avian leukosis virus subgroup J and discuss their significance, chicken embryo fibroblast (CEF) cells were inoculated with Avian leukosis virus subgroup J strain NX0101 and samples were tested continuously for ten days after changing maintenance media. The correlation between TCID50 and p27 antigen S/P value of ten days were then analysized. Simultaneously, DF-1 cells were inoculated with NX0101 and passaged to 20 generations. Samples taken from 1st generation, 5th generation, 10th generation, 15th generation and 20th generation were tested for the TCID50 titer and the p27 antigen S/P value separately. A significant Pearson correlation was found between them in CEF cells (r = 0.85277; P < 0.0001) and in DF-1 cells (r = 0.93000; P = 0.0220). This study provided an important parameter for predicting TCID50 by detecting the p27 antigen S/P value.

Isolation and identification of a subgroup B avian leukosis virus from chickens of Chinese native breed Luhua / 病毒学报

By inoculation of blood samples in DF-1 (C/E) cell culture, an exogenous avian leukosis virus (ALV) strain SDAU09C2 was isolated from a breeder farm of Chinese native breed "Luhua" in Shandong province. Comparisons of the amino acid sequence of env gene gp85 from the isolate with those from other ALV reference strains of different subgroups indicated that SDAU09C2 had the highest gp85 identity to two reference strains of subgroup B of 92.5%. Its gp85 identity to other chicken ALV subgroups A, C, D, E was in the range of 73.2%-87.9%. The identity to subgroup J was only 30.3%-32.4%. This is the first report on isolation and identification of ALV-B and its gp85 from Chinese native breed chickens.

Different strategies for preparation of non-tagged rV270 protein and its efficacy against Yersinia pestis challenge / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>LcrV is an important component for the development of a subunit vaccine against plague. To reduce immunosuppressive activity of LcrV, a recombinant LcrV variant lacking amino acids 271 to 326 (rV270) was prepared by different methods in this study.</p><p><b>METHODS</b>A new strategy that produced non-tagged or authentic rV270 protein was designed by insertion of rV270-thrombin-hexahistidine fusion gene into the vector pET24a, or by insertion of hexahistidine-enterokinase-rV270 or hexahistitine-factor Xa-rV270 fusion gene into the vector pET32a. After Co(2+) affinity chromatography, a purification strategy was developed by cleavage of His tag on column, following Sephacryl S-200HR column filtration chromatography.</p><p><b>RESULTS</b>Removal of His tag by thrombin, enterokinase and factor Xa displayed a yield of 99.5%, 32.4% and 15.3%, respectively. Following Sephacryl S-200HR column filtration chromatography, above 97% purity of rV270 protein was obtained. Purified rV270 that was adsorbed to 25% (v/v) Al(OH)₃ adjuvant in phosphate-buffered saline (PBS) induced very high titers of antibody to rV270 in BALB/c mice and protected them (100% survival) against subcutaneous challenge with 10⁶ CFU of Y. pestis virulent strain 141.</p><p><b>CONCLUSION</b>The completely authentic rV270 protein can be prepared by using enterokinase or factor Xa, but they exhibited extremely low cleavage activity to the corresponding recognition site. Thrombin cleavage is an efficient strategy to prepare non-tagged rV270 protein and can be easily operated in a large scale due to its relatively low cost and high cleavage efficacy. The recombinant rV270 can be used as a key component to develop a subunit vaccine of plague.</p>

Evaluation of immunization protection efficacy of plague subunit vaccine / 中华预防医学杂志

<p><b>OBJECTIVE</b>To evaluate the protective efficacy of plague subunit vaccine, BALB/c mice, guinea pigs and rabbits were used in this study.</p><p><b>METHODS</b>Groups of mice (10 per group), guinea pigs (14 per group) and rabbits (6 per group) were immunized with F1 + rV270 vaccine, EV76 vaccine and alum adjuvant by intramuscular route, respectively. Serum antibody titres of mice, guinea pigs and rabbits were determined by ELISA and the immunized animals were challenged with 10(6) CFU of Y. pestis strain 141 at the 8th week after the primary immunization.</p><p><b>RESULTS</b>The immunized mice, guinea pigs or rabbits with subunit vaccine developed anti-F1 IgG titre of 41 587.3 +/- 2.1, 11 543.7 +/- 2.1 or 522.4 +/- 22.4 and elicited statistical anti-F1 IgG titre difference among them (F = 17.58, P < 0.01). The immunized mice, guinea pigs or rabbits with subunit vaccine had anti-rV270 IgG titre of 15 748.7 +/- 1.6, 12.6 +/- 1.4 or 1648.0 +/- 5.0 and induced statistical anti-rV270 IgG titre difference among them (F value was 16.34, P < 0.01). There was significant anti-F1 IgG titre difference among mice, guinea pigs and rabbits immunized with EV76 vaccine that developed anti-F1 IgG titre of 913.4 +/- 4.5, 937.0 +/- 2.0 or 342.0 +/- 12.0 (F = 23.67, P < 0.01), whereas the immunized mice, guinea pigs and rabbits with EV76 vaccine developed anti-rV270 IgG titre of 12.0 +/- 1.0, 447.0 +/- 10.0, 40.0 +/- 11.0 and there was no anti-rV270 IgG titre difference between them (F = 2.20, P = 0.1314). The immunized mice with subunit vaccine developed significantly higher anti-F1 IgG titres than immunized guinea pigs and rabbits (q value was 30.57 and 19.04, respectively, P < 0.01), and there were no anti-F1 IgG titre differences between the immunized guinea pigs and rabbits (q = 0.04, P = 0.8485). The immunized mice with subunit vaccine developed significantly higher anti-rV270 IgG titres than immunized guinea pigs and rabbits (q value was 27.10 and 19.49, respectively, P < 0.01), and there were no anti-rV270 IgG titre differences between the immunized guinea pigs and rabbits with the subunit vaccine (q = 0.25, P = 0.6187). The immunized mice with EV76 elicited higher anti-F1 IgG titres than immunized guinea pigs and rabbits (q value was 40.67 and 29.10, respectively, P < 0.01), whereas there was no difference of F1 IgG titer between immunized guinea pigs and rabbits (q = 0.06, P = 0.8098). The immunized mice, guinea pigs and rabbits with subunit vaccine provided 100% (10/10), 86% (12/14) and 100% (5/5) protection against 10(6) CFU Y. pestis of challenge, respectively. The immunized mice, guinea pigs and rabbits with EV76 vaccine gave 100% (6/6), 93% (13/14) and 100% (6/6) protection against 10(6) CFU Y. pestis of challenge respectively.</p><p><b>CONCLUSION</b>BALB/c mice is the best small animal model for valuation of protective efficacy of plague subunit vaccine. The guinea pigs showed a high individual variation for this purpose. The rabbits can be used as an alternative model for evaluating plague subunit vaccine.</p>