Objective To determine the function of conserved amino acids in the fusion-promoting domain of Newcastle disease virus (NDV) hemagglutinin-neuraminidase (HN) protein,clearly understanding mechanism of cell fusion.MethodsUsing a PCR-based site-directed mutagenesis method and the method of homology recombination occurred in vivo to change six conservative amino acids into alanine respectively.Wild type (WT) and all mutant HN proteins were exepressed in BHK-21 cells by the vacciniaT7 RNA polymerase expression system.The amount of each HN protein at the cell surface was determined by fluorescence-activated cell sorter (FACS).Cell fusion efficiency,hemadsorption activity (or receptor binding activity) and neuraminidase activity were determined.Results There was no statistic difference of cell surface expression among WT and each mutant HN protein ( P＜0.05 ).Cell fusion efficiency of each mutant protein decreased to some extent,especially 1103A decreased to 14.2％ in head.Hemadsorption activity of mutant proteins were reduced in different extent,the maximum reduction of which was also 1103A,28.2％ of wt NDV HN.There was different neuraminidase activity among each mutant HN protein.L74A increased slightly to 118.6％.L110A decreased most to 5.2％.I103A decreased second most to 5.7％.Conclusion Conserved amino acids in fusion-promoting domain of NDV HN played an important role in cell fusion.I103 was identified as a key amino acid in this domain.

Objective To develop and evaluate an up-converting phosphor technology-based lateral flow assay ( UPT-LF) for detection of aflatoxin M1(AFM1) in milk powder and milk.Methods AFM1-UPT-LF was established with up-converting phosphor ( UCP) nano-particles as the bio-label of competitive mode based LF assay .Sensitivity, quantitative ability and precision were evaluated using simulated AFM 1-postive samples with serial standard concentrations .The qualita-tive and quantitative detection performance of AFM 1-UPT-LF was evaluated with reference to liquid chromatography-mass spectrography ( LC-MS) to detect samples of milk powder and milk simultaneously .Results AFM1-UPT-LF could conduct qualitative and quantitative detection without sample pretreatment within 20 min.The detection limit of AFM1-UPT-LF reached 0.1 μg/kg in milk powder and 0.3 μg/L in milk.There was good linearity ranging from 0.1 to 0.7 μg/kg and 0.3 to 0.7 μg/L for milk powder and milk, respectively.The sensitivity, specificity and receiver operating characteristic ( ROC) area under the curve ( AUC) of AFM1-UPT-LF for qualitative result could meet the need of national standards for AFM1 limit in dairy products.After statistical analysis, there was no significant difference (milk powder: t=0.66, P>0.05;milk:t=1.01, P>0.05) between AFM1-UPT-LF and LC-MS for quantitative detection .Conclusion The good qualitative and quantitative detection performance of AFM 1-UPT-LF for milk powder and milk makes possible on-site rapid detection of AFM1 in dairy products quantitatively .

Viral myocarditis (VM) refers to human infections thermophilic myocardium virus that causes the circumscribed or diffuse myocardium-inflammatory lesion.Myocarditis can be caused by a variety of microbial infections,and VM is the most common one.In order to make the medical staff in clinical work have a more in-depth understanding of VM,this paper describes the common rviruses related,VM and its pathogenesis,process.At present,there is no effective drug and treatment method for VM.It is particularly important to further study the pathogenesis of VM on the role of the virus in,and inhibit its role in the further exploration of clinical therapeutic targets,to improve the quality of life of patients with VM and prolong the survival time is of great significance.Studying in-depth virus in the pathogenesis of VM and restraining its function are particularly important for the further exploration of clinical therapeutic targets.It is significant to improve the life quality and prolong the survival time for VM patients.

ObjectiveTo study the effect of sub-chronic exposure to deltamethrin(DM) on neural behavior and expression of NMDA receptor in hippocampus of mice.Methods 60 Female SPF Kunming mice were divided into 4 groups and given DM 60 days by gavage.Hot-plate,rotarod,grip strength,hing limb landing foot splay were used to examine the sensory and motor change of mice.Autonomic activity test was used for detecting the functional status of the central nervous system in mice.Passive avoidance test for detection of the behavior changes of learning and memory,and RQ-PCR was employed to measure the expression of NMDA receptor in hippocampus of mice.ResultsThe behavior of sensory and motor of mice sub-chronic exposure to deltamethrin did not have changes significantly(P ＞ 0.05 ).In the test of autonomic activity test,the average of autonomic activity times were (93 ± 18) times,(107 ± 13) times,(105 ±22) times.Compared with the control group,the average of autonomic activity times in middle-and high-dose groups were increased significantly (P ＜ 0.05 ).The latent periods in poisoning groups were (175.4 ±38.4) s,(146.4 ±51.2)s,(132.3 ±45.0) s,and the error times were (0.7 ±0.3)times,( 1.4 ± 0.5 ) times,( 1.8 ± 0.9) times.Compared with the control group,latent periods of high-dose group were decreased and the error times of middle-and high-dose groups were increased significantly (P ＜ 0.05 ).Compared with the control group,the relative expression levels of NR1 and NR2A mRNA in hippocampus of middle and high-dose groups were increased significantly (P＜ 0.05 ),and the relative expression level of NR2B mRNA in highdose group was decreased significantly(P ＜ 0.05).ConclusionSub-chronic exposure to DM could increase the excitability of mice,damage the function of learning and memory,and influence the expression of NMDA receptor in hippocampus of mice.

Objective To construct a chimeric infectious clone of the fatal virulent strain SDLY 107, containing the gene fragments encoding 2A and 3B proteins of the mild virulent strain SDLY 1, and to establish a reverse genetic system platform for further investigation on virulence of enterovirus 71 strains. Methods The overlap PCR analysis was performed to obtain the gene fragments encoding 2A and 3B pro-teins of the mild virulent strain SDLY 1.The obtained gene fragments were digested and then cloned into a plasmid pMD19-T containing the full-length gene of SDLY 107 strain by using gene replacement strategy. The recombinant RNA was transfected into Vero cells for the preparation of recombinant virus particles.Sev-eral assays including the PCR, indirect immunofluorescence ( IFA) , Western blot and sequencing were per-formed for virus identification.Virus titers were measured by 50%cell culture infective dose ( CCID50 ) and plaque assay.Results The infectious clones of SDLY 107-2A-1 and SDLY 107-3B-1 chimeric virus strains were constructed successfully.Typical cytopathic effect was observed in Vero cells after viral transfection. Identification of the rescued viruses by PCR, IFA, Western blot and sequencing further confirmed the suc-cessful construction of infectious virus strains.The virus titers of SDLY 107-2A-1 and SDLY 107-3B-1 strains detected by CCID50 and plaque assay were 1.25 ×105 PFU/ml and 0.7 ×105 PFU/ml, respectively. Conclusion The chimeric viruses SDLY 107-2A-1 and SDLY 107-3B-1 were rescued successfully, causing cytopathic effects similar to those by using the parental virus strain SDLY 107.This study might pave the way for further investigation on in vitro and in vivo virulence of enterovirus 71 strains.

OBJECTIVE: To explore the effect of intense pulsed laser (IPL) on anti-aging and its mechanism. METHODS: Rat skin was continuously irradiated ex vivo by IPL at certain wavelengths with different energy densities. The rats were irradiated twice with an interval of 2 weeks. We measured superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, hydroproline (Hyp) content, and the level of apoptosis-related gene B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein (Bax) in the IPL treatment groups, and then compared with those in the model groups and the control group. RESULTS: SOD activity and Hyp content in the IPL treatment groups were higher than those in the model groups, and MDA content in the IPL treatment group was lower than that in the model group (P<0.05). IPL irradiation increased Bcl-2 protein content in rat skin cells, but had no effect on Bax protein expression. CONCLUSION IPL is effective to improve the appearance of aging skin. Its mechanism may relate to maintaining the balance of oxidation and anti-oxidation, restoring oxidase activity, and regulating the death of skin cells by increasing Bcl-2 expression.
Animals ; Female ; Lasers ; Proline ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rats ; Skin ; enzymology ; metabolism ; Skin Aging ; radiation effects ; Superoxide Dismutase ; metabolism ; bcl-2-Associated X Protein ; metabolism

Objective To evaluate the effect of cardiopulmonary bypass (CPB) on the expression of hypothalamic nerve growth factor precursor (proNGF) and the influence of hypothalamic proNGF on the sympathetic output of paraventrucular nucleus. Methods Forty-two male SD rats, aged 3-4 months, weighing 350-500 g, were divided into control group, CPB group and ischemia reperfusion (IR) group. At the end of CPB for 110 min, hypothalamus and dorsal root ganglion (DRG) were taken to measure the levels of proNGF mRNA and hypothalamic proNGF protein. Mini pipe was put into bilateral paraventrucular nucleus (PVN) and human recombination proNGF protein was injected into PVN for 7 d before the local field potentials (LFP) of RVLM was recoreded. Human recombination proNGF protein was administrated into lateral ventricle, the prior-administration-LFP of PVN and post-administration-LFP were recorded and compared. At the end of the experiment, hypothalamus was taken to measure the levels of glutamate and gammer amino butyric acid (GABA). Results Hypothalamic proNGF protein in CPB group and IR group was higher than that in the control group (P ＜ 0.05); NGF mRNA of hypothalamus and DRG in CPB and IR group were higher than those of control group (P ＜ 0.05). In PVN and RVLM, after the administration of proNGF protein, the power of delta band significantly decreased and other bands increased (P ＜ 0.05). The hypothalamic GABA level decreased (P ＜ 0.05) with no change of hypothalamic glutamate after proNGF was injected into lateral ventricle. Conclusion CPB increases the expression of proNGF in the hypothalamus contributing to the changes of hypothalamic sympathetic output.

Objective To explore the efficacy of triple therapy and sequential therapy in the eradication of helicobacter pylori in liver cirrhosis patients with hyperammonia (Hp). Methods A total of sixty-eight liver cirrhosis patients with hyperammonia and positive Hp infection were randomly divided into triple eradication group and sequential eradication group. Results The eradication rates of Hp in triple therapy group and sequential therapy group were 79.4%(27/34)and 85.3% (29/34)respectively. There was no significant difference between the two groups(χ2=0.41, P>0.05). In the triple therapy group, the blood ammonia concentration of after treatment and one month after withdrawal of drugs de-creased significantly compared with before the treatment (t=4.02, 5.11, P<0.01).In the sequential therapy group, the blood ammonia concentration of after treatment and one month after withdrawal of drugs decreased significantly com-pared with before the treatment (t=4.68, 5.83, P<0.01).The fall of ammonia concentration was not statistical different between the two groups(P>0.05). Conclusion There is no significant difference in Hp eradication between triple therapy and sequential therapy in liver cirrhosis patients with hyperammonia.

Objective To construct a predictive model for the survival of transplant kidneys after kidney transplantation. Methods The clinical data of 366 kidney transplant recipients and donors were retrospectively analyzed, and the recipients were divided into low-risk group (n=101), medium-risk group (n=189), and high-risk group (n=76) based on the kidney donor profile index (KDPI). Each group was further divided into Remuzzi score ≤3 group and Remuzzi score >3 group based on time-zero biopsy Remuzzi scores. Kaplan-Meier method was used to analyze the survival of transplant kidneys. Univariate and multivariate Cox regression analyses were performed to identify risk factors affecting long-term survival after kidney transplantation. A predictive model for transplant kidney survival was established and a nomogram was drawn. The predictive performance of the model was evaluated using the receiver operating characteristic (ROC) curve and the area under the curve (AUC). Results The median KDPI was 65%, and the median Remuzzi score was 3. The 5-year survival rate of transplant kidneys was 83.5%. Kaplan-Meier survival curves showed that in the KDPI medium-risk and KDPI high-risk groups, the subgroup with lower Remuzzi score had a higher survival rates of transplant kidneys than the subgroup with higher Remuzzi score. Univariate and multivariate Cox regression analyses showed that KDPI, Remuzzi score, and donor’s age were independent risk factors for transplant kidney loss (all P<0.05). The ROC curve showed that the AUC of the nomogram prediction model established based on independent risk factors for the 1, 3 and 5-year survival rates of transplant kidneys were 0.91, 0.93 and 0.94 for the training set, and 0.89, 0.85 and 0.88 for the validation set. Calibration curves shows good consistency between the training and validation sets of the model. Conclusions The nomogram predictive model based on KDPI, time-zero biopsy Remuzzi score and donor’s age has good predictive value for transplant kidney survival.

Objective:To explore the clinical characteristics and outcomes of SARS-CoV-2 infection in kidney transplant recipients(KTRs)and examine the risk factors for severe/critical infection.Methods:A retrospective analysis was conducted for 208 adult KTRs diagnosed with SARS-CoV-2 infection between December 15, 2022, and March 15, 2023.They were assigned into two groups of mild/ordinary(n=168)and severe/critical(n=40)according to the severity of SARS-CoV-2 infection.Two groups were compared with regards to general profiles, status of baseline vaccination against COVID-19, transplant history, immunosuppressive regimens, comorbidities and treatment outcomes.For continuous variables, t or Mann-Whitney U test was utilized for comparing the inter-group differences.For categorical variables, chi-square or Fisher's exact test was employed.Bonferroni correction was applied for multiple comparisons when p value was ≤0.05.Logistic regression analysis of univariates and multivariates was conducted for identifying the risk factors for severe/critical infections.Results:The rates of hospitalization, severe illness, ICU admission, mechanical ventilation and mortality among 208 KTRs with COVID-19 were 27.4%(57/208), 19.2%(40/208), 3.4%(7/208), 5.3%(11/208)and 1.9%(4/208)respectively.Among 57 COVID-19 infected individuals, 43.9%(25/57)experienced bone marrow suppression with an incidence of anemia 36.8%(21/57)and thrombocytopenia 22.8%(13/57). The lowest counts of whole blood lymphocyte, CD4 + T lymphocyte and CD8 + T lymphocyte were 390.0(245.0, 615.0), 138.0(78.0, 293.5)and 180.0(94.7, 575.2)cells/μL respectively.The incidence of bacterial, cytomegaloviral, Pneumocystis jirovecii and other fungal infections after COVID-19 infection was 17.8%(37/208), 3.8%(8/208), 2.9%(6/208)and 2.9%(6/208)respectively.The severe/critical group had a higher incidence of other pathogen infections as compared to mild/ordinary group, including bacterial infections[62.5%(25/40)vs 7.1%(12/168), 95% CI: 47.5%~63.3%, P<0.001], cytomegaloviral infections[15.0%(6/40)vs 1.2%(2/168), 95% CI: 8.1%~19.5%, P=0.001], P.jirovecii infections[15%(6/40)vs 0(0/168), 95% CI: 9.4%~20.6%, P<0.001]and other fungal infections of Candida, Cryptococcus, Malassezia and Aspergillus fumigatus[15.0%(6/40)vs 0(0/168), 95% CI: 9.4%~20.6%, P<0.001]. The incidence of acute kidney injury(AKI)after COVID-19 infection was 13.5%(28/208)and severe/critical group had a higher incidence of AKI than mild/ordinary group[52.5%(21/40)vs 4.2%(7/168), 95% CI: 40.3% to 56.3%, P<0.001]. Univariate analysis showed that age( P=0.003), male gender( P=0.002), smoking history( P=0.012), coronary heart disease( P=0.011), diabetes mellitus( P=0.002), chronic renal insufficiency( P=0.001)and pulmonary disease history( P=0.001)were significantly different between severe/critical and mild/ordinary groups.Multivariate regression analysis revealed that comorbid chronic kidney disease( OR=3.34, 95% CI: 1.46-7.64, P=0.004)and a history of lung disease( OR=3.42, 95% CI: 1.49-7.87, P=0.004)were independent risk factors for severe/critical illness.Baseline vaccination rate against COVID-19 was 17.8%(37/208). Completion of baseline vaccination was associated with a lower risk of severe/critical COVID-19 infection( OR=0.28, 95% CI: 0.08-0.98, P=0.047). Conclusions:KTRs with severe/critical COVID-19 infections are more prone to multiple pathogen co-infections and the incidence of kidney function impairment after infection has remained relatively high.Histories of pulmonary and chronic kidney diseases are independent risk factors for severe/critical infections.Completion of baseline vaccination provides protection against severe/critical infections.