Objective To assess the role of Matrix Metalloproteinase-9 (MMP-9)in rheumatoid arthritis (RA).Methods Peripheral blood from 45 RA patients and 28 healthy individuals (HV)were collected to detect RF and hs-CRP by immuno-turbidimetry,ESR by westergren method and MMP-9 by ELISA.The correlation was analysed between MMP-9 and RF, ESR or hs-CRP,respectively,by pearson correlation analysis.Results Levels of RF,ESR,hs-CRP and MMP-9 were signifi-cantly higher in RA patients than HV group (t=3.93~5.96,P<0.001),respectively.RF high titer patients or patients with a high inflammation response showed a higher MMP-9 levels than the RF low titer or slight inflammation patients (P<0.05).MMP-9 was positively correlated to RF,ESR and hs-CRP in RA patients(P<0.05),respectively.Conclusion MMP-9 maybe a sensitive tool in the diagnosis and management of RA patients.

Objective To investigate the role and the mechanism of ppk1 gene (coding for polyphosphate kinase 1) in oxidative stress resistance in uropathogenic Escherichia coli (UPEC).MethodsMutant strains with ppk1-deletion (△pk1) and complemented strains (△pk1-C) were constructed based on the UPEC strain CFT073.A comparative analysis was conducted to analyze survival rates of CFT073, △pk1 and △pk1-C strains at different time points while they were under oxidative stress.Differences in protein expression between CFT073 and △pk1 strains were analyzed using mass spectrometric analysis.Differences between CFT073 and △pk1 strains in expression of katG and katE genes were analyzed using real-time quantitative RT-PCR.Results The survival rate of △pk1 strains was lower than that of CFT073 strains at every time point, while the survival rate of △pk1-C strains was basically the same as that of CFT073 strains.Gel image analysis and mass spectrometric analysis revealed that six proteins were down-regulated and one was up-regulated in △pk1 strains as compared with those in CFT073 strains.Expression of the catalase-coding genes katG and katE in △pk1 strains were respectively (20.5±8.2)% and (20.9±6.9)% of those in CFT073 strains (P<0.05).Conclusion The ppk1 gene plays an important role in oxidative stress resistance in UPEC by modulating the expression of catalase-coding genes katG and katE.

Objective.The present study investigated the role of endogenous carbon monoxide(CO)in the pathogenesis of neointimal formation induced by balloon injury in rat.Method.Endothelial denudation of the left common carotid artery of rat was carried out by three passages of a Fogarty 2F balloon catheter.DNA,collagen and elastin contents of each intima-media were estimated;and heme oxygenase(HO)activity and CO production in vascular smooth muscle cell(VSMC)were measured after administration of HO inhibitor.Result.Our data showed that neointima occurred in the rat on day 7 and day 21 after balloon injury,and at the same time HO activity and CO production in VSMC were markedly increased.Administration of HO inhibitor,zinc deuteroporphyrin 2,4-bisglycol(ZnDPBG),could effectively inhibit HO activity and CO production,significantly enhance neointimal formation(aortic intima/media ratio were 21.4±1.8% vs 17.6±2.0%,P＜0.05 on day 7;and 30.5±2.4% vs 23.0±2.2%,P＜0.01 on day 21,respectively,compared with balloon alone group).Conclusion.We concluded that 1)inhibition of CO production may enhance neointimal formation induced by endothelial denudation,implying endogenous CO play an protective role in response to vascular injury,and 2)induction of HO activity may be applied clinically for preventing restenosis after angioplasty.

Objective: To explore the Expressions of multiple inflammation markers in the patients with 2019 novel coronavirus pneumonia (COVID-19) and their clinical values, and to provide theoretical basis for clinical diagnosis and treatment. Methods: A total of 164 patients, diagnosed with COVID-19 and admitted to Guangzhou Eighth People's Hospital from January to February 2020, were selected as the research group and divided into three groups (ordinary, severe, and critically severe pneumonia) according to the disease severity. Meandwhile 66 non-infected patients during the same period were selected as negative control group. The expressions of WBC, LYM, CRP, SAA, and PCT were retrospective studied and compared between groups. The diagnostic values of WBC, CRP, SAA and the combination of these three markers in all patients with COVID-19 and in different severity groups were analyzed by ROC curve. Results: Compared with control group (WBC count :8.13(6.51,9.42)×10⁹/L, LYM count:2.00(1.28,2.43)×10⁹/L), WBC count [4.94(4.05, 6.67) ×10⁹/L] and LYM count [1.33(0.94, 1.96) ×10⁹/L] of COVID-19 patients were significantly reduced (Z=-7.435, P<0.01; Z=-4.906, P<0.01) . Compared with the control group [CRP: 1.36 (0.57~5.67) mg/ml; SAA:[4.98 (4.80~15.75) mg/mL], CRP [7.93 (2.45~23.98) mg/ml] and SAA [34.13 (4.83~198.40) mg/ml] were increased in research group (Z=-5.72, P<0.01; Z=-4.166, P<0.01) . PCT in the control group and the research group were 0.100 0(0.030 6~0.100 0)ng/ml and 0.044 5(0.031 6~0.077 0)ng/ml, respectively. There was no statistical difference between two groups (Z=-1.451, P=0.147) . The areas under the ROC curve (AUC) of WBC, CRP and SAA in patients with COVID-19 were 0.814, 0.742, 0.673, respectively (P<0.01), while the AUC of the combination of three indexes for COVID-19 diagnosis was 0.882, with 83.33%(55/66) specificity and 84.76% (139/164) sensitivity, P<0.01.The AUCs of WBC, CRP, and SAA for predicting severe and critically severe COVID-19 were 0.799, 0.779, and 0.886 , respectively (P<0.01), and the AUC of the combination of three indexes for the diagnosis of severe and critically severe COVID-19 was 0.924, with 78.67% (118/150) specificity and 14/14 sensitivity (P<0.01). Conclusion Combining detection of WBC, CRP and SAA can improve the specificity and sensitivity of COVID-19 diagnosis, with a high diagnostic value for severe and critically severe COVID-19.

Objective:To evaluate the performance of three antibody kits for novel coronavirus (SARS-CoV-2) and to investigate the feasibility and advantages of them in clinical application.Methods:A total of 104 patients who were admitted to Guangzhou Eighth People′s Hospital with COVID-19 from January to February 2020 were selected as research group. Fifty-one healthy subjects were selected during the same period as negative control group. Serum antibodies (IgM/IgG) against SARS-CoV-2 were detected using two kinds of colloidal gold kits (A and B kits) and one chemiluminescence kit (C kit). The positive rates of SARS-CoV-2 nucleic acid in different samples from patients with COVID-19 were retrospectively analyzed.Results:The clinical sensitivity of A kit to detect SARS-CoV-2-specific IgM and IgG was 77.88% (81/104) and 65.38% (68/104), respectively, and the clinical specificity was 70.59% (36/51) and 100.00% (51/51). However, the false positive rate in IgM detection was as high as 29.41% (15/51). The sensitivity of B kit to test total antibodies to SARS-CoV-2 was 63.46% (66/104), and the clinical specificity was 94.12% (48/51). The clinical sensitivity of C kit to detect SARS-CoV-2-specific IgM and IgG were respectively 31.73% (33/104) and 64.42% (67/104), and the clinical specificity were both 98.04% (50/51). There was a moderate correlation between the detection results of two colloidal gold kits and the chemiluminescence kit with the Kappa values of 0.462 and 0.587 ( Z=6.157, P<0.01; Z=7.345, P<0.01). C kit had the highest positive detection rate for IgG, and would be more reliable to be used for IgG detection in COVID-19 patients 14 d after onset. The total positive detection rate of nucleic acid in all types of samples was 63.46% (66/104). The highest positive detection rate was in throat swabs or sputum samples, followed by those in blood samples and anal swabs. No viral nucleic acid was detected in urine samples for the time being. Conclusions:SARS-CoV-2-specific antibodies could be detected in the early or late stage of COVID-19. The method of antibody detection has the advantages of shorter detection time, simple operation and high biological safety, indicating that it could be used as a supplementary or auxiliary detection for the diagnosis of suspected COVID-19 cases with negative nucleic acid test results. The chemiluminescence kit has good sensitivity and specificity, and is well recommended for clinical laboratories.

Objective To summarize changes in antibiotic resistance of Salmonella typhimurium enteritis in children in our hospital and analyze its treatment.Methods A total of 186 children with Salmonella typhimurium enteritis in the pediatrics department of our hospital were selected.The drug resistance of common antibiotics against Salmonella typhimurium for children was analyzed,and the annual and pre-/post-treatment changes of multi-drug resistant bacteria were also analyzed.Based on the initial treatment of antibiotics and the first drug sensitivity test results,patients were divided into the initial sensitive group(121 cases)and the initial insensitive group(65 cases).The hospital stay and fecal culture negative conversion time were compared between the two groups of children.Results Among the Salmonella typhimurium isolated from 186 children,the resistance rate of Salmonella typhimurium to commonly used cephalosporin antibiotics in pediatrics demonstrated an overall upward tendency.Among them,the resistance rates of ceftriaxone(43.6%)and cefotaxime(35.5%)were relatively high.From 2017 to 2019,the proportion of multi-drug resistant bacteria presented a gradual upward trend,while from 2020 to 2023,the proportion declined.The incidence of multi-drug resistant bacteria exhibited an increasing trend after treatment(P＜0.05).After 1 week of treatment,there were no significant differences in the above three types of drug resistance changes.The hospital stay and the time for fecal culture to turn negative were both shorter in the initial sensitive group than those in the initial insensitive group(P＜0.05).Conclusion The problem of bacterial resistance in Salmonella typhimurium enteritis in children is severe.Initial empirical treatment with sensitive antibiotics and a reasonable course of anti-infective treatment can help reduce the bacterial drug resistance rate and shorten the hospital stay.

BACKGROUND:Intervertebral disc degeneration is an important cause of low back pain.At present,there are many modeling methods for disc degeneration in China and abroad,but there is not a model for low back pain due to disc degeneration. OBJECTIVE:To compare the effect of mechanical puncture combined with tumor necrosis factor α and complete Freund's adjuvant with a conventional disc mechanical puncture alone. METHODS:A total of 18 male adult Sprague-Dawley rats were randomly divided into 3 groups,with 6 animals in each group.No treatment was given in the blank group.Animal models of intervertebral disc degeneration were made in the L4-5 segments of rats in the control using conventional mechanical puncture.In the experimental group,on the basis of mechanical puncture,tumor necrosis factor α+complete Freund's adjuvant was injected into the L4-5 intervertebral discs using a microinjector to establish a model of disc degeneration induced by mechanical puncture combined with inflammatory factors.Four weeks after surgery,the pain threshold of rats was measured by the hot plate method for assessing the perception of heat injury in rats with intervertebral disc degeneration.MRI examination was performed to observe the disc degeneration in each group.ELISA was used to detect the levels of serum tumor necrosis factor α,interleukin 1β,interleukin 6 and prostaglandin E2.Hematoxylin-eosin and Safranin O-fast green staining were used to observe the morphological changes of the disc. RESULTS AND CONCLUSION:In terms of pain,the behavioral pain threshold of the experimental group was continuously decreased,and the levels of serum inflammatory factors were significantly higher compared with the control group.In terms of morphology,the MRI results showed that the L4-5 nucleus pulposus signal completely disappeared in the experimental group.Histopathological results showed that in the control group,the nucleus pulposus was intact,more notochord cells were visible,and some fiber rings were ruptured,while in the experimental group,there are fewer notochord cells and the structure of the nucleus pulposus and fibrous ring is disturbed,with the boundary disappearing.To conclude,mechanical puncture combined with tumor necrosis factor alpha and complete Freund's adjuvant can successfully establish a discogenic low back pain model in rats.This operation is simple and economical to achieve obvious disc degeneration and low back pain,with greatly shortened molding cycle.This model can be used as a reference for studying discogenic low back pain models.