Mannheimia varigena(M.varigena)is a significant pathogen causing bovine respiratory disease.Transferrin binding protein B(TbpB)is a lipoprotein directly exposed to the outer mem-brane of the cell,which is not only involved in the bacterial iron metabolism pathway,but also an important virulence factor.This study aims to lay the groundwork for developing novel subunit vaccines by conducting site-directed mutagenesis on M.varigena TbpB binding-related residues and evaluating their immunogenicity.Based on whole-genome sequencing of a bovine M.varigena i-solate,its iron uptake pathway was predicted.Key amino acid residues of M.varigena TbpB that play a role for binding to bovine transferrin(bTf)was identified by bioinformatics.We constructed two M.varigena TbpB mutants(Y205A and Y258A)and assessed their bTf binding activity and immunogenicity through dot blot assays and mouse immunization studies.Dot blot assays result showed that the Y258A mutation caused TbpB to lose its ability to bind to bTf.Mouse immuniza-tion studies showed that,compared to wild-type TbpB,the mutants of TbpB induced higher levels of specific antibodies.In challenge experiments,mice immunized with mutant TbpB exhibited high-er survival rates.These results demonstrate that site-directed mutagenesis can enhance the immu-nogenicity of TbpB.This study provides a novel approach for developing new subunit vaccines a-gainst M.varigena.

Mannheimia varigena(M.varigena)is a significant pathogen causing bovine respiratory disease.Transferrin binding protein B(TbpB)is a lipoprotein directly exposed to the outer mem-brane of the cell,which is not only involved in the bacterial iron metabolism pathway,but also an important virulence factor.This study aims to lay the groundwork for developing novel subunit vaccines by conducting site-directed mutagenesis on M.varigena TbpB binding-related residues and evaluating their immunogenicity.Based on whole-genome sequencing of a bovine M.varigena i-solate,its iron uptake pathway was predicted.Key amino acid residues of M.varigena TbpB that play a role for binding to bovine transferrin(bTf)was identified by bioinformatics.We constructed two M.varigena TbpB mutants(Y205A and Y258A)and assessed their bTf binding activity and immunogenicity through dot blot assays and mouse immunization studies.Dot blot assays result showed that the Y258A mutation caused TbpB to lose its ability to bind to bTf.Mouse immuniza-tion studies showed that,compared to wild-type TbpB,the mutants of TbpB induced higher levels of specific antibodies.In challenge experiments,mice immunized with mutant TbpB exhibited high-er survival rates.These results demonstrate that site-directed mutagenesis can enhance the immu-nogenicity of TbpB.This study provides a novel approach for developing new subunit vaccines a-gainst M.varigena.

Objective To investigate the risk factors of microcirculation obstruction(MVO)after reperfusion in patients with acute myocardial infarction(AMI).Methods Forty-one patients with AMI who received treatment with myocardial reperfusion were retrospectively selected.Cardiac magnetic resonance(CMR)was used to determine whether the patients had MVO.The patients were divided into MVO and non-MVO groups.The basic data,laboratory examination and CMR parameters of patients were collected and compared between the groups,and the risk factors related to MVO were screened out by logistic regression analysis.Results Delayed myocardial enhancement was observed in all 41 patients,among which 11 cases(26.8%)were with MVO.A total of 206 delayed myocardial enhancement segments were observed,of which 77 segments combined with MVO and 129 segments without MVO.AMI patients with MVO had a higher rate of transmural myocardial infarction,greater infarct volume,left ventricular myocardial mass(LVMM)and edema degree,as well as lower ejection fraction of left and right ventricles(P<0.05).Multivariate logistic regression analysis indicated that infarct volume[odds ratio(OR)=1.116,95%confidence interval(CI)1.017-1.224,P=0.020]was an independent risk factor for MVO after AMI reperfusion.Conclusion Infarct volume is an independent risk factor for MVO after AMI reperfusion,and MVO is associated with left and right ventricular function impairment.

ObjectiveTo investigate the current status and high-risk factors of chromosomal aberrations in peripheral blood lymphocytes （PBL） of radiation workers in Hainan Province. MethodsA total of 200 radiological workers who underwent occupational health examination in Hainan Provincial Hospital of Traditional Chinese Medicine from January 2021 to December 2021 were selected to collect the occupational health examination data and the rate of PBL chromosomal aberrations. The influencing factors of PBL chromosomal aberrations were analyzed by logistic regression model. The predictive value of logistic regression prediction model on PBL chromosomal aberrations were determined by using the reciver operator characteristic （ROC） curve. ResultsA total of 20 000 cells （100 cells/person） were tested. The chromosomal aberration rate was 0.37% （74/20 000） and the PBL chromosomal aberration rate in the subjects was 6.00% （12/200）. Univariate analysis showed that PBL chromosomal aberrations in radiological workers were related to age， length of service， type of work and education （all P<0.05）， but not to gender （P>0.05）. The logistic regression prediction model was constructed based on the influencing factors， with χ²=9.413， df=9， P=0.852， suggesting a good model fit. The logistic regression prediction model predicted the area under the curve （AUC） for the occurrence of PBL chromosomal aberrations in radiation workers was 0.914 （95%CI： 0.866‒0.949）， with a cut-off value of 3.05， corresponding to a prediction sensitivity and specificity of 100.00% and 75.98%， respectively. ConclusionThe incidence of PBL chromosomal aberrations in radiological workers in Hainan Province was 6.00%， with age， working age and job type as high-risk factors and education level as a protective factor. The prediction model constructed by the above factors can provide a reliable basis for clinical prediction of PBL chromosomal aberrations in radiological workers.

Very long chain polyunsaturated fatty acids (VLC-PUFAs) are unique fatty acids in tissues of mammals such as retina and testis, and the key enzyme of its biosynthesis is very long chain fatty acid elongase 4 (Elovl4). Development of an animal model of tissue-specific knockout of Elovl4 gene is conducive to the in-depth study of the biological function of VLC-PUFAs. Therefore, we constructed Stra8-Cre mice and Elovl4 floxed mice based on Cre/loxP system, and obtained the (Elovl4[flox/+], Stra8-Cre) heterozygous knockout mice by hybridization. Subsequently, female mice were selected to cross with male mice with homozygous Elovl4[flox/flox] to gain homozygous mice (Elovl4[flox/flox], Stra8-Cre) through genotype identification and screening. RT-PCR, qRT-PCR, Western blotting, immunohistochemistry and immunofluorescence techniques were used to detect the knock-out efficiency of Elovl4 in testis. The expression of Elovl4 in testis of both heterozygous and homozygous knockout mice were significantly down-regulated at mRNA and protein levels, but were not affected in other tissues. In summary, we constructed a mouse model with specific knockout of Elovl4 gene in testis, which provides a reliable animal model for studying the effect of VLC-PUFAs on the reproductive function of male mice and the underpinning molecular mechanisms.
Animals ; Disease Models, Animal ; Eye Proteins/metabolism* ; Female ; Gene Knockout Techniques ; Integrases ; Male ; Mammals/metabolism* ; Membrane Proteins/metabolism* ; Mice ; Mice, Knockout ; Testis/metabolism*

Systemic treatment is the first choice for patients with advanced hepatocellular carcinoma. Atezolizumab combined with bevacizumab can bring better survival for patients with advanced hepatocellular carcinoma. The authors introduce the efficacy and safety management of a hepatocellular carcinoma case with postoperative recurrence who received treatment of atezoli-zumab combined with bevacizumab. The patient had a probability of pseudoprogression during treatment, and had a good result of a continuous partial response over 2 years.

【Objective】 To investigate the clinical efficacy and safety of low-dose rituximab combined with dexamethasone in the treatment of refractory ITP (RITP) in children. 【Methods】 A total of 31 RITP children, admitted to the Hematology Department of Kunming Children′s Hospital from January 2016 to December 2019 and agreed to receive low-dose rituximab (100 mg/ time, once a week, for 4 successive weeks) combined with dexamethasone (0.6 mg/kg, once a day, for 4 successive days) were enrolled and studied. Blood routine was monitored every other day during treatment, and adverse drug reactions were recorded. The influence of gender, disease course and age on prognosis was compared by χ² test. 【Results】 1) Among the 31 cases, 11 (35.5%) had platelets >100×10⁹/L after 4 weeks and had no recurrence in 6 months; 9 (29%) had platelets >30×10⁹/L but <100×10⁹/L and had no recurrence in 6 months; 11 (35.5%) showed no recovery of platelets, which were consistently lower than 30×10⁹/L. 2) Rituximab was used in 4 cases (12.9%), 1 case (3.2%) presented with severe drug-induced rashes; Headache, vomiting and elevated blood pressure occurred in 2 cases (6.4%). 1 case (3.2%) presented with laryngeal edema. 3) There was no difference in the total effective rate among different gender, age and disease course (P >0.05). 【Conclusion】 The total effective rate of low-dose rituximab combined with dexamethasone for children with refractory ITP in 6 months is 64.5%, and the adverse reactions are tolerable, so it can be used as a treatment option for children with refractory ITP.

Objective: To investigate the efficacy of 200IU hepatitis B immunoglobulin (HBIG) injection at 1 month after birth to interrupt the mother-to-children transmission (MTCT) of hepatitis B virus (HBV). Methods: Infants born to mothers who were hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) positive, with HBV DNA load ≥1.0×10⁶ IU/ml and who did not receive antiviral drug treatment during pregnancy, were randomly divided into 2 groups. Infants in the control group were treated with standard immunoprophylaxis: 200 IU HBIG and 10 μg recombinant hepatitis B vaccine injection within 2 h after birth and a vaccine booster at 1 and 6 months after birth. For infants in the HBIG group the standard immunoprophylaxis and an additional 200 IU HBIG were administered at 1 month. HBsAg, the antibody to HBsAg (anti-HBs), and HBV DNA load were measured at birth and after 7 months. later.Immunoprophylaxis failure was defined as the presence of HBV DNA and HBsAg positivity or the presence of HBV DNA and HBsAg negativity at 7 months. Results: In this prospective cohort study, of the 280 infants enrolled, 14 infants (HBIG/control: 6/8) were lost to follow-up and 266 subjects (HBIG/control: 134/132) completed the 7-month study. The log₁₀HBV DNA load of mothers in the HBIG group and control group were (7.31±0.66) log₁₀IU/ml and (7.32±0.74) log₁₀IU/ml, respectively (P=0.92). The MTCT rate of the two groups was similar (5.97% vs. 7.58%, P=0.63). At 7 months, the HBsAg positive rate and the level of anti-HBs in the two groups were 94.03%(126/134)vs. 91.67% (121/132) and 623.60±412.93 mIU/mL vs. 620.38±399.10 mIU/ml, respectively with no significant difference (P=0.48 and P=0.95, respectively). The log₁₀ HBV DNA load of mothers in immunoprophylaxis failure group and success group was similar (P=0.09). The number of infants who were serum HBsAg positive and HBV DNA positive at birth in the immunoprophylaxis failure group were higher than those in the success group (100% and 100% vs. 35.89% and 31.85%, P<0.01, respectively). The serum HBsAg levels in infants at birth was the only independent relevant factor for HBV MTCT, with risk rates of 11.18 (95% Confidence interval (CI), 1.23-101.88), 352.00 (95%CI, 15.82-7833.20), and 968.00 (95%CI 81.35-11519.19) for HBsAg levels of 0.05-< 1, 1-< 10, and ≥ 10 IU/ml, respectively, compared to infants with HBsAg levels < 0.05 IU/ml. Conclusions Administering 200IU HBIG injection at 1 month did not reduce the risk of HBV MTCT.

According to the phenomenon that the curriculum of psychological health education for college students is theoretical,lack of experience and the teaching form is single,this research attempts to private a blended teaching which is based on the small private online course (SPOC) and experiential teaching.The content of mental health is divided into theoretical knowledge and experience knowledge.And the theoretical knowledge is taught through online teaching in the form of massive open online courses (MOOC),while the experiential knowledge is taught by pure experiential teaching in the classroom.The study has summed up 3 stages of learning mode:learning before class,teaching experience and reflection after class.This changes the single classroom theory teaching to students experience learning.Besides,formative evaluation is used as assessment methods,which has enhanced the effectiveness of the course and at the same time,it has also promoted the improvement of teachers' teaching level effectively.

Objective To compare the Barcelona clinic liver cancer staging classification (BCLC), the Japan integrated staging score (JIS), the cancer of the liver Italian program score (CLIP) and Chinese staging system in terms of their ability to predict outcomes and to guide option of therapy in patients with hepatocellular carcinoma (HCC) in China.Methods Clinical data of 861 HCC patients from Zhongshan Hospital between 2001 and 2002 were retrospectively analyzed. Patients were classified acccording to different staging systems. Survival for patients in different stages and the effects of therapeutic methods on survival time were compared. Results BCLC, JIS and Chinese staging system showed the ability in predicting survival for patients in different staging. CLIP failed to show significant difference in survival rates for each subgroup. There was no significant difference in survival rate between surgery and transarterial chemoembolization (TACE)/transarterial embolization (TAE) for patients classified as BCLC stage C, CLIP scores more than 3 or Chinese stage Ⅲ a.The survival rate, however, was higher in patients received operation than those received TACE/TAE if they were classified as earlier stages. Conclusions The BCLC, JIS and Chinese staging systems show prospective ability for Chinese HCC patients in prediction outcomes, whereas the BCLC and the Chinese staging systems are better at both predicting outcomes and guiding the option of treatment.