This study was aimed at identifying the pathogenic bacteria responsible for the death of a young tiger at the Fujian Meihua Mountain South China Tiger Breeding Research Institute.Tissue samples from the lungs,liver,and intestines of the deceased tiger were collected,and the bacteria were cultured inasterile environment.The bacterial strains were characterized according to their morphological and molecular biological properties,including assessment of virulence genes and antibiotic resistance genes,mouse lethality tests,and antibiotic susceptibility evaluations.A predominant bacterial strain isolated from the liver of the deceased tiger was identified as enterotoxigenic Escherichia coli(ETEC)strain Tiger22513F.Phylogenetic analysis of the 16S rRNA gene revealed that the Tiger22513F strain exhibited close genetic similarity to the reference strain ETEC(MF919609.1),with 99.9%nucleotide similarity,and resided on the same evolutionary branch.The Tiger22513F strain contained 11 antibiotic resistance genes(tetA,sul1,sul3,cmlA,floR,blaTEM,blaSHV,blaCMY-2,qnrA,qnrS,and qnrD)along with five virulence genes(VT1,fyuA,tsh,iucD,and ST).Mouse lethality tests indicated significant pathogenicity toward mice,affecting primarily the lungs,liver,and intestines.Antibiotic susceptibility testing demonstrated that this strain exhibited resistance to various classes of beta-lactam antibiotics,as well as quinolones and aminoglycosides.This investigation successfully isolated a multi-drug resistant enterotoxigenic Escherichia coli strain with pronounced pathogenicity from the liver of a deceased tiger;thus providing valuable scientific insights for clinical diagnosis,as well as prevention and control measures,against ETEC infections in South China tigers.

Objective To propose a ventilator failure probability prediction method based on kernel ridge regression(KRR).Methods Firstly,the failure interval data of ventilators was collected and preprocessed to remove outliers.Secondly,the median rank method was used to estimate the failure probability.Finally,using the time data as the feature variable and the failure probability value as the target variable,a KRR model was established and trained by selecting the optimal kernel function and hyperparameter combination from radial basis kernel function,linear kernel function,polynomial kernel function,and S-type kernel function through grid search and cross-validation methods to predict ventilator failures.To verify the performance of the KRR model in predicting ventilator failure probability,it was compared with Weibull and its extended models.Results KRR achieved a coefficient of determination of 0.993 5,a mean squared error of 5.399 5×10-4,a root mean squared error of 0.023 2 and a mean absolute error of 0.018 3,outperforming Weibull and its extended models in prediction accuracy and error control.Conclusion The failure probability prediction method for ventilators based on KRR demonstrates exceptional performance in prediction accuracy and error control,and thus holds great potential for application.[Chinese Medical Equipment Journal,2025,46(5):73-77]

Objective To investigate the effects of ischemia time and storage periods on RNA quality in fresh-frozen breast cancer(BC)and esophageal cancer(EC)tissue samples in order to establish evidence-based protocols for biobank sample management.Methods The tumor(T)and paired normal(N)tissue samples from 6 cases of BC and 6 cases of EC were collected and cryopreserved in Biobank,Shantou Central Hospital.Mirror paraffin-embedded tissues were simultaneously prepared into sections for morphological analysis.The samples were divided into two groups of<15 min and 15-30 min according to ischemia time,and RNA quality was analyzed at 4 storage periods of 8-10 months(T1),14-16 months(T2),26-28 months(T3)and 38-40 months(T4).Results In 96 analyzed samples,93.8%(90/96)exhibited high quality(RIN≥6),with 89.6%(43/48)in BC and 97.9%(47/48)in EC.Significant differences in RIN were observed between BC group and EC group(8.050 vs.8.600,P=0.009).In EC group,RIN value was significantly negatively correlated with RNA yield(P<0.001).Moreover,RIN values of tumor-normal pairs exhibited markedly significant differences(7.550 vs.9.000,P<0.001).In contrast,no significant difference was detected in BC group(8.200 vs.7.700,P=0.348).Statistical analysis showed that RIN value was positively correlated with 28S/18S(P<0.001),but had no correlation with tumor content(P=0.676)and necrotic content(P=0.055).Neither ischemia time(<15 min vs.15-30 min:8.200 vs.8.300,P=0.932)nor storage periods(T1-T4:8.400,7.700,8.450,8.600,P=0.163)compromised RNA quality.Conclusion Organ origin and tissue type could influence RNA quality of fresh-frozen tissue samples.However,limited ischemia time(≤30 min)and long-term storage period(38-40 months)do not adversely affect RNA quality in fresh-frozen breast cancer and esophageal cancer tissue samples.

In view of the characteristics of H5N6 subtype avian influenza virus(AIV)that it has both high pathogenicity and the risk of cross-species transmission,posing a serious threat to the poultry farming industry and public health security,in order to effectively prevent and control the spread of H5N6 avian influenza,a rapid,sensitive and specific detection technolo-gy was established in this study.The specific monoclonal antibodies against the neuraminidase N6 protein of avian influenza A virus subtype H5N6 were obtained through hybridoma and monoclonal antibody technology.These antibodies were coupled and labeled with carboxyl-functionalized fluorescent quantum dots,along with previously prepared specific antibodies against the hemagglutinin H5 protein.A rapid fluorescence immunochromatographic detection method for the H5N6 subtype of avian influ-enza virus was established according to the principle of double-antibody sandwich immunochromatography.This method a-chieved a detection sensitivity of 1 ng/mL for recombinant hemagglutinin H5 subtype protein and 0.1 ng/mL for recombinant neuraminidase N6 subtype protein.Moreover,the method exhibited no cross-reactivity with other influenza subtypes or patho-gens,such as Newcastle disease(ND),infectious bronchitis(IB),and infectious laryngotracheitis(ILT),thus demonstrating good specificity.The method effectively identified the highly pathogenic avian influenza virus H5 subtype and directly distin-guished the H5N6 subtype with good accuracy.The fluorescent quantum dot immunochromatographic typing detection method established herein met the sensitivity,specificity,and accuracy requirements for H5N6 subtype detection,and can be further used for rapid detection of the H5 and H5N6 subtypes of avian influenza virus.

Objective:To explore the diagnostic value of shear wave elastography(SWE)for clinically significant prostate cancer(csPCa).Methods:We retrospectively analyzed the clinical data of 359 cases with suspected prostate cancer(PCa)in Baoji Central Hospital from June 2017 to July 2023.All the patients underwent the following examinations in the order of serum prostate-spe-cific antigen(PSA)testing,transrectal ultrasonography(TRUS),measurement of the stiffness of the entire prostate gland by SWE,and TRUS-guided prostate puncture biopsy.The stiffness of the entire prostate gland was defined as the average of Young's modulus at both sides of the base,middle,and apex of the prostate,including the maximum Young's modulus(Emax),mean Young's modulus(Emean),and minimum Young's modulus(Emin).We analyzed the correlation of the parameters of the stiffness of the entire prostate gland with the pathological results,focusing on their diagnostic performance for csPCa.Results:Of the 359 cases,189 were diag-nosed by pathological puncture biopsy as BPH,26 as non-csPCa,and 144 as csPCa.The PSA level,Emax,Emean and Emin were significantly higher in the csPCa than those in the BPH and non-csPCa groups(all P＜0.01),but showed no statistically significant difference between the BPH and non-csPCa groups(all P＞0.05).The area under the receiver operating characteristic curve(AUC),optimal cut-off value,sensitivity,specificity,positive predictive value(PPV),negative predictive value(NPV)and accura-cy of Emax in the diagnosis of csPCa were 0.852,143.92 kPa,72.22％,84.65％,75.91％,81.98％and 79.67％;those of Emean were 0.868,82.42 kPa,67.36％,91.16％,83.62％,80.66％and 81.62％;and those of Emin were 0.682,32.73 kPa,47.22％,89.30％,73.91％,71.54％and 72.14％,respectively.In the non-csPCa group,Emax,Emean and Emin were found be-low the optimal cut-off value in 73.08％(19/26),92.31％(24/26)and 88.46％(23/26),respectively.Conclusion:The stiff-ness of the entire prostate gland measured by SWE contributes to the diagnosis of csPCa,reduces unnecessary detection of non-csPCa,and provides some reference for its active surveillance.

This study was aimed at identifying the pathogenic bacteria responsible for the death of a young tiger at the Fujian Meihua Mountain South China Tiger Breeding Research Institute.Tissue samples from the lungs,liver,and intestines of the deceased tiger were collected,and the bacteria were cultured inasterile environment.The bacterial strains were characterized according to their morphological and molecular biological properties,including assessment of virulence genes and antibiotic resistance genes,mouse lethality tests,and antibiotic susceptibility evaluations.A predominant bacterial strain isolated from the liver of the deceased tiger was identified as enterotoxigenic Escherichia coli(ETEC)strain Tiger22513F.Phylogenetic analysis of the 16S rRNA gene revealed that the Tiger22513F strain exhibited close genetic similarity to the reference strain ETEC(MF919609.1),with 99.9%nucleotide similarity,and resided on the same evolutionary branch.The Tiger22513F strain contained 11 antibiotic resistance genes(tetA,sul1,sul3,cmlA,floR,blaTEM,blaSHV,blaCMY-2,qnrA,qnrS,and qnrD)along with five virulence genes(VT1,fyuA,tsh,iucD,and ST).Mouse lethality tests indicated significant pathogenicity toward mice,affecting primarily the lungs,liver,and intestines.Antibiotic susceptibility testing demonstrated that this strain exhibited resistance to various classes of beta-lactam antibiotics,as well as quinolones and aminoglycosides.This investigation successfully isolated a multi-drug resistant enterotoxigenic Escherichia coli strain with pronounced pathogenicity from the liver of a deceased tiger;thus providing valuable scientific insights for clinical diagnosis,as well as prevention and control measures,against ETEC infections in South China tigers.

Objective To propose a ventilator failure probability prediction method based on kernel ridge regression(KRR).Methods Firstly,the failure interval data of ventilators was collected and preprocessed to remove outliers.Secondly,the median rank method was used to estimate the failure probability.Finally,using the time data as the feature variable and the failure probability value as the target variable,a KRR model was established and trained by selecting the optimal kernel function and hyperparameter combination from radial basis kernel function,linear kernel function,polynomial kernel function,and S-type kernel function through grid search and cross-validation methods to predict ventilator failures.To verify the performance of the KRR model in predicting ventilator failure probability,it was compared with Weibull and its extended models.Results KRR achieved a coefficient of determination of 0.993 5,a mean squared error of 5.399 5×10-4,a root mean squared error of 0.023 2 and a mean absolute error of 0.018 3,outperforming Weibull and its extended models in prediction accuracy and error control.Conclusion The failure probability prediction method for ventilators based on KRR demonstrates exceptional performance in prediction accuracy and error control,and thus holds great potential for application.[Chinese Medical Equipment Journal,2025,46(5):73-77]

Objective To explore the risk factors for puncture site complications after radiofrequen-cy catheter ablation(RFCA)in elderly patients with tachyarrhythmias.Methods A retrospective study was conducted on 290 elderly tachyarrhythmic patients undergoing RFCA in our depart-ment from January 2017 to June 2023.According to the occurrence of postoperative complications during hospitalization,they were divided into a complication group(13 cases)and a non-complica-tion group(277 cases).The basic clinical data were compared between the two groups.Multivari-ate logistic regression analysis was used to identify the independent influencing factors for periop-erative puncture site complications in RFCA,and ROC curves were plotted to determine the pre-dictive value of BMI on puncture site complications.Results Puncture site complications were more common in atrial arrhythmia radiofrequency ablation,followed by supraventricular arrhyth-mia,and but rare in ventricular arrhythmia,with statistical difference in the incidence(P=0.014).The complication group had significantly higher BMI and larger proportion of atrial ar-rhythmias when compared with the non-complication group(P＜0.05).There were no statistical differences between the two groups in terms of age,proportions of ventricular arrhythmia,su-praventricular arrhythmia,hypertension and type 2 diabetes(P＞0.05).Multivariate logistic re-gression analysis showed that higher BMI was a risk factor for puncture site complications in eld-erly tachyarrhythmic patients after RFCA(OR=1.256,95％CI:1.032-1.528,P=0.023).ROC curve analysis indicated that the AUC value of BMI in predicting puncture site complications was 0.702(95％CI:0.586-0.817,P=0.018),with a sensitivity of 91.7％,a specificity of 49.6％,and a Yoden index of 0.413.Conclusion RFCA for atrial arrhythmias is closely associated with punc-ture site complications,and BMI has a predictive value for the complications of puncture site.

Objective To explore the risk factors for puncture site complications after radiofrequen-cy catheter ablation(RFCA)in elderly patients with tachyarrhythmias.Methods A retrospective study was conducted on 290 elderly tachyarrhythmic patients undergoing RFCA in our depart-ment from January 2017 to June 2023.According to the occurrence of postoperative complications during hospitalization,they were divided into a complication group(13 cases)and a non-complica-tion group(277 cases).The basic clinical data were compared between the two groups.Multivari-ate logistic regression analysis was used to identify the independent influencing factors for periop-erative puncture site complications in RFCA,and ROC curves were plotted to determine the pre-dictive value of BMI on puncture site complications.Results Puncture site complications were more common in atrial arrhythmia radiofrequency ablation,followed by supraventricular arrhyth-mia,and but rare in ventricular arrhythmia,with statistical difference in the incidence(P=0.014).The complication group had significantly higher BMI and larger proportion of atrial ar-rhythmias when compared with the non-complication group(P＜0.05).There were no statistical differences between the two groups in terms of age,proportions of ventricular arrhythmia,su-praventricular arrhythmia,hypertension and type 2 diabetes(P＞0.05).Multivariate logistic re-gression analysis showed that higher BMI was a risk factor for puncture site complications in eld-erly tachyarrhythmic patients after RFCA(OR=1.256,95％CI:1.032-1.528,P=0.023).ROC curve analysis indicated that the AUC value of BMI in predicting puncture site complications was 0.702(95％CI:0.586-0.817,P=0.018),with a sensitivity of 91.7％,a specificity of 49.6％,and a Yoden index of 0.413.Conclusion RFCA for atrial arrhythmias is closely associated with punc-ture site complications,and BMI has a predictive value for the complications of puncture site.

Objective To investigate the effects of ischemia time and storage periods on RNA quality in fresh-frozen breast cancer(BC)and esophageal cancer(EC)tissue samples in order to establish evidence-based protocols for biobank sample management.Methods The tumor(T)and paired normal(N)tissue samples from 6 cases of BC and 6 cases of EC were collected and cryopreserved in Biobank,Shantou Central Hospital.Mirror paraffin-embedded tissues were simultaneously prepared into sections for morphological analysis.The samples were divided into two groups of<15 min and 15-30 min according to ischemia time,and RNA quality was analyzed at 4 storage periods of 8-10 months(T1),14-16 months(T2),26-28 months(T3)and 38-40 months(T4).Results In 96 analyzed samples,93.8%(90/96)exhibited high quality(RIN≥6),with 89.6%(43/48)in BC and 97.9%(47/48)in EC.Significant differences in RIN were observed between BC group and EC group(8.050 vs.8.600,P=0.009).In EC group,RIN value was significantly negatively correlated with RNA yield(P<0.001).Moreover,RIN values of tumor-normal pairs exhibited markedly significant differences(7.550 vs.9.000,P<0.001).In contrast,no significant difference was detected in BC group(8.200 vs.7.700,P=0.348).Statistical analysis showed that RIN value was positively correlated with 28S/18S(P<0.001),but had no correlation with tumor content(P=0.676)and necrotic content(P=0.055).Neither ischemia time(<15 min vs.15-30 min:8.200 vs.8.300,P=0.932)nor storage periods(T1-T4:8.400,7.700,8.450,8.600,P=0.163)compromised RNA quality.Conclusion Organ origin and tissue type could influence RNA quality of fresh-frozen tissue samples.However,limited ischemia time(≤30 min)and long-term storage period(38-40 months)do not adversely affect RNA quality in fresh-frozen breast cancer and esophageal cancer tissue samples.