Objective:To investigate the association between congenital hypothyroidism (CH) and the adverse outcomes during hospitalization in very low birth weight infants (VLBWI).Methods:This prospective, multicenter observational cohort study was conducted based on the data from the Sino-northern Neonatal Network (SNN). Data of 5 818 VLBWI with birth weight <1 500 g and gestational age between 24-<37 weeks that were admitted to the 37 neonatal intensive care units from January 1 st, 2019 to December 31 st, 2022 were collected and analyzed. Thyroid function was first screened at 7 to 10 days after birth, followed by weekly tests within the first 4 weeks, and retested at 36 weeks of corrected gestational age or before discharge. The VLBWI were assigned to the CH group or non-CH group. Chi-square test, Fisher exact probability method, Wilcoxon rank sum test, univariate and multivariate Logistic regression were used to analyze the relationship between CH and poor prognosis during hospitalization in VLBWI. Results:A total of 5 818 eligible VLBWI were enrolled, with 2 982 (51.3%) males and the gestational age of 30 (29, 31) weeks. The incidence of CH was 5.5% (319 VLBWI). Among the CH group, only 121 VLBWI (37.9%) were diagnosed at the first screening. Univariate Logistic regression analysis showed that CH was associated with increased incidence of extrauterine growth retardation (EUGR) ( OR=1.31(1.04-1.64), P<0.05) and retinopathy of prematurity (ROP) of stage Ⅲ and above ( OR=1.74(1.11-2.75), P<0.05). However, multivariate Logistic regression analysis showed no significant correlation between CH and EUGR, moderate to severe bronchopulmonary dysplasia, grade Ⅲ to Ⅳ intraventricular hemorrhage, neonatal necrotizing enterocolitis in stage Ⅱ or above, and ROP in stage Ⅲ or above ( OR=1.04 (0.81-1.33), 0.79 (0.54-1.15), 1.15 (0.58-2.26), 1.43 (0.81-2.53), 1.12 (0.70-1.80), all P>0.05). Conclusion:There is no significant correlation between CH and in-hospital adverse outcomes, possibly due to timely diagnosis and active replacement therapy.

Objective:To investigate the interaction between fibroblasts (Fb) and keratinocytes (KC) in the wound edge skin tissue of a diabetic foot patient and the mechanism.Methods:This was an experimental research. The wound edge skin tissue from a diabetic foot patient (male and 33 years old) admitted to the Department of Wound Repair of Liyuan Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology in August 2021 and from an acute foot injury patient (male and 50 years old) admitted to the Department of Hand Surgery of the hospital in September 2021 was collected. The single-cell transcriptome sequencing was performed to analyze the interaction between chemokine ligands of Fb subgroup and chemokine receptors of KC subgroup. The supernatant was collected after human foreskin fibroblast (HFF) was cultured routinely and with high concentration of glucose for 7 days as normal conditioned medium (CM) and high glucose CM, respectively. HaCaT cells were collected and divided into normal CM group cultured with normal CM and high glucose CM group cultured with high glucose CM, the scratch test was performed to calculate the cell migration rates at 24 and 48 h after scratch ( n=3). The content of cytokines in the two kinds of CM was detected by liquid suspension chip ( n=5). HFF was collected and divided into normal group cultured routinely and high glucose group cultured with high concentration of glucose for 7 days, and the mRNA expressions of C-X-C motif chemokine ligand 1 (CXCL1), CXCL2, CXCL8, and CXCL12 were detected by real-time fluorescence quantitative reverse transcription polymerase chain reaction ( n=6). HaCaT cells in normal CM group and high glucose CM group were collected to detect the protein expressions of C-X-C motif chemokine receptor 4 (CXCR4) in cells cultured for 48 h by Western blotting ( n=3). HaCaT cells were collected and divided into normal CM group, high glucose CM group, normal CM+CXCL12 group, and high glucose CM+CXCL12 group. The first two groups of cells were treated as before, and the latter two groups of cells were cultured with normal CM and high glucose CM containing recombinant human CXCL12, respectively. Scratch test was performed, and cell migration rates were calculated at 24 and 48 h after scratch ( n=3); the protein expression of CXCR4 in cells cultured for 48 h was detected by Western blotting ( n=3). Results:Compared with those in the wound edge skin tissue of acute foot injury, the interactions between chemokine ligands (CXCL1, CXCL2, CXCL3, CXCL8, and CXCL12) of Fb subgroup and chemokine receptors (CXCR2 and CXCR4) of KC subgroup were significantly weakened in the wound edge skin tissue of diabetic foot. At 24 and 48 h after scratch, the migration rates of HaCaT cells in high glucose CM group were significantly lower than those in normal CM group (with t values of 23.50 and 15.65, respectively, P<0.05). Compared with that in normal CM, the content of CXCL1 in high glucose CM was significantly increased ( P<0.05), and the content of CXCL12 was significantly decreased ( P<0.05). After 7 days of culture, compared with those in normal group, the mRNA expressions of CXCL1, CXCL2, and CXCL8 in HFF in high glucose group were significantly increased (with t values of 4.25, 4.98, and 10.04, respectively, P<0.05), while the mRNA expression of CXCL12 was significantly decreased ( t=4.10, P<0.05). After 48 h of culture, the CXCR4 protein expression in HaCaT cells in high glucose CM group was significantly lower than that in normal CM group ( t= 5.13, P<0.05). At 24 and 48 h after scratch, the migration rates of HaCaT cells in high glucose CM group were significantly lower than those in normal CM group and high glucose CM+CXCL12 group (with P values all <0.05); at 24 h after scratch, the migration rate of HaCaT cells in normal CM+CXCL12 group was significantly lower than that in normal CM group ( P<0.05); at 48 h after scratch, the migration rate of HaCaT cells in normal CM+CXCL12 group was significantly higher than that in high glucose CM+CXCL12 group ( P<0.05). At 48 h of culture, the CXCR4 protein expression of HaCaT cells in high glucose CM+CXCL12 group was 0.446±0.050, which was significantly higher than 0.247±0.010 in high glucose CM group ( P<0.05) and similar to 0.522±0.082 in normal CM+CXCL12 group ( P>0.05); the CXCR4 protein expression in HaCaT cells in normal CM group was 0.509±0.055, which was significantly higher than that in high glucose CM group ( P<0.05). Conclusions:The interactions between chemokine ligands of Fb subgroup and chemokine receptors of KC subgroup were significantly weakened in the wound edge skin tissue of diabetic foot. High glucose can inhibit CXCL12 secretion of HFF, and the stimulation of its cell culture supernatant can decrease HaCaT cell migration ability and CXCR4 expression. Exogenous CXCL12 protein can increase the CXCR4 protein expression in HaCaT cells and enhance the cell migration ability.

Objective:To explore the risk factors for atrial fibrillation in adult patients with critically severe burns after the first surgery.Methods:This study was a retrospective case series study. From January 1, 2018 to March 31, 2023, 211 adult patients with critically severe burns were admitted to the Department of Burns of Tongren Hospital of Wuhan University & Wuhan Third Hospital and met the inclusion criteria, including 158 males and 53 females, aged 24-81 years. According to whether atrial fibrillation occurred after the first surgery, the patients were divided into postoperative atrial fibrillation (POAF) group (23 cases) and non-POAF group (188 cases). The following indexes of patients in POAF group were collected, including the onset time, duration, treatment method, and number of patients with more than once of atrial fibrillation after the first surgery. The following data of the two groups of patients were collected, including general data, such as gender, age, burn type, total burn area, full-thickness burn area, inhalation injury, underlying diseases, mechanical ventilation, and sepsis; electrolyte imbalance and blood index level before the first surgery; the first surgery-related information such as surgical length and surgical method; volume changes and vital signs during the first surgery, such as total volume of fluid infusion, total volume of blood transfusion, volume of blood loss, hypotension, and hypothermia; postoperative hypothermia; inflammatory index levels before the first surgery and on the first day after the first surgery, such as procalcitonin levels, white blood cell count, neutrophil count, lymphocyte count, platelet count, neutrophil to lymphocyte ratio (NLR), platelet count to lymphocyte ratio (PLR); mortality within 30 days of admission. The independent risk factors for occurrence of atrial fibrillation in adult patients with critically severe burns after the first surgery were screened.Results:The onset time of atrial fibrillation of patients in POAF group was 2 (2, 4) hours after the first surgery, and the duration of atrial fibrillation was 16 (6, 26) hours. Twenty-one patients were treated with intravenous injection of amiodarone, two patients were treated with cardiac electrical cardioversion, and atrial fibrillation of all patients converted to sinus rhythm after treatment. Three patients experienced atrial fibrillation more than once. The age was 59 (42, 70) years and the total burn area was 90% (70%, 94%) total body surface area (TBSA) in patients in POAF group, which were significantly higher than 48 (38, 56) years and 70% (60%, 83%) TBSA in non-POAF group (with Z values of -2.64 and -3.56, respectively, P<0.05). Compared with those in non-POAF group, the incidence rate of inhalation injury of patients in POAF group was significantly higher ( χ2=4.45, P<0.05), the total volumes of fluid infusion and blood transfusion during the first surgery were significantly increased (with Z values of -3.98 and -3.75, respectively, P<0.05), the incidence rates of hypothermia during the first surgery and hypothermia after the first surgery were significantly increased (with χ2 values of 8.24 and 18.72, respectively, P<0.05), the levels of procalcitonin before the first surgery and on the first day after the first surgery, as well as the NLR on the first day after the first surgery were significantly increased (with Z values of -3.03, -2.19, and -2.18, respectively, P<0.05), the lymphocyte count (with Z values of -2.07 and -2.60, respectively, P<0.05) and platelet count (with Z values of -3.35 and -3.58, respectively, P<0.05) were significantly reduced before the first surgery and on the first day after the first surgery, and the mortality rate within 30 days of admission was significantly higher ( χ2=4.03, P<0.05). There were no statistically significant differences in other indexes between the two groups of patients ( P>0.05). Multivariate logistic regression analysis showed that age, total burn area, and intraoperative hypothermia were independent risk factors for the occurrence of atrial fibrillation in adult patients with critically severe burns after the first surgery (with odds ratios of 1.08, 1.07, and 4.18, 95% confidence intervals of 1.03-1.12, 1.03-1.11, and 1.48-11.80, respectively, P<0.05). Conclusions:Age, total burn area, and intraoperative hypothermia are independent risk factors for the occurrence of atrial fibrillation in adult patients with critically severe burns after the first surgery. Patients with atrial fibrillation have an increased risk of death.

Background::Hepatitis B virus (HBV) infection is the primary cause of hepatocellular carcinoma (HCC) in China. The target population for HCC screening comprises individuals who test positive for hepatitis B surface antigen (HBsAg). However, current data on the prevalence of HBV infection among individuals who are eligible for HCC screening in China are lacking. We aimed to assess the seroepidemiology of HBV infection among Chinese individuals eligible for HCC screening to provide the latest evidence for appropriate HCC screening strategies in China.Methods::Questionnaires including information of sex, age, ethnicity, marital status, educational level, source of drinking water, as well as smoking and alcohol consumption history and serum samples were collected from females aged 45–64 years and males aged 35–64 years in 21 counties from 4 provinces in eastern and central China between 2015 and 2023. Enzyme-linked immunosorbent assay methods were used to detect the serum HBV marker HBsAg.Results::A total of 603,082 individuals were enrolled, and serum samples were collected for analysis from January 1, 2015 to December 31, 2023. The prevalence of HBsAg positive in the study population was 5.23% (31,528/603,082). The prevalence of HBsAg positive was greater in males than in females (5.60% [17,660/315,183] vs 4.82% [13,868/287,899], χ 2 = 187.52, P <0.0001). The elderly participants exhibited a greater prevalence of HBV infection than younger participants (χ 2 = 41.73, P <0.0001). Birth cohort analysis revealed an overall downward trend in HBV prevalence for both males and females. Individuals born in more recent cohorts exhibited a lower prevalence of HBV infection as compared to those born earlier. Conclusions::The current prevalence of HBV infection remains above 5% in populations eligible for HCC screening in China.

Background::Liver cancer remains the sixth most commonly diagnosed cancer and the third leading cause of cancer-related deaths worldwide, causing a heavy burden globally. An updated assessment of the global epidemiology of the liver cancer burden that addresses geographical disparities is necessary to better understand and promote healthcare delivery.Methods::Data were extracted from the GLOBOCAN 2022 database, including the number, crude, and age-standardized rates of incidence and mortality at the global, country, continent, and human development index (HDI) regional levels. Age-standardized rates (incidence and mortality) per 100,000 person-years were adjusted based on the Segi-Doll World standard population. The mortality-to-incidence ratios (MIR) for each region and country were calculated. The HDI and gross national income (GNI) for 2022 were obtained, and a Pearson correlation analysis was conducted with the incidence, mortality, and MIR.Results::In 2022, approximately 866,136 new liver cancer cases and 758,725 related deaths were recorded worldwide, with a global MIR of 0.86. Males had a disproportionately higher burden than females across all levels, and the highest burden was observed in the elderly population. Geographically, the regions with the highest incidence rates included Micronesia, Eastern Asia, and Northern Africa, and the regions with the highest mortality rates included Northern Africa, Southeastern Asia, Eastern Asia, and Micronesia. Notably, Mongolia had a strikingly high burden compared to other countries. The highest MIR was observed in North America and the lowest in Africa. Negative associations of HDI and GNI with liver cancer mortality and MIR were identified, irrespective of sex.Conclusions::The current liver cancer burden underscores the presence of remarkable geographic heterogeneity, which is particularly evident across countries with varying HDI levels, highlighting the urgent need to prioritize health accessibility and availability to achieve health inequities.

Objective To explore the mechanism of butylphthalide(NBP)in regulating microglia acti-vation and inflammatory cytokine expression in the hippocampus of the mouse model of delayed encephalopathy af-ter carbon monoxide poisoning(DEACMP).Methods Wild-type C57 adult mice with normal cognitive function were selected,and DEACMP was modeled by static inhalation of carbon monoxide.The mice were randomized in-to three groups:DEACMP,control,and NBP.The NBP group was administrated with NBP suspension at 6 mg/kg by gavage for 21 days,and the DEACMP and control groups were administrated with the same amount of vegeta-ble oil by gavage.The hippocampal injury was observed by HE staining.The protein level of ionized calcium-bind-ing adapter molecule 1(IBA1)was determined by Western blotting,and the levels of downstream inflammatory cytokines were measured by ELISA.Results Compared with the control group,the DEACMP and NBP groups showed prolonged escape latency(P=0.001,P=0.029),reduced nerve cells(P=0.001,P=0.035),up-regulated expression of IBA1(P=0.001,P=0.042),increased mean fluorescence intensity of IBA1(P=0.001,P=0.021),and elevated levels of tumor necrosis factor-α(TNF-α)(P=0.002,P=0.024),inter-leukin(IL)-6(P=0.001,P=0.015),and IL-1β(P=0.001,P=0.023).Compared with the DEACMP group,the NBP group showed shortened escape latency(P=0.025),increased nerve cells(P=0.039),down-regulated expression of IBA1(P=0.035),decreased average fluorescence intensity of IBA1(P=0.031),and lowered levels of TNF-α(P=0.028),IL-6(P=0.037),and IL-1 β(P=0.034).Conclusion NBP can inhibit the activation of microglia and reduce the expression of inflammatory factors,thereby alleviating cog-nitive dysfunction and brain tissue damage caused by DEACMP.

Objective:To explore the suitable prostate cancer screening mode under the medical community for primary hospitals.Methods:From April 2021 to April 2022, a total of 16007 male population ≥50 years from 9 branches of the medical community of the second hospital of Yinzhou participated in this study. They were divided into four groups according to age with group 1 of 50-59 years old, group 2 of 60-69 years old, group 3 of 70-79 years old, and group 4 of 80 years old and above. Serum tPSA was added to the routine physical examination, and the screening positive patients were referred to the referral hospital for further diagnosis and treatment under the mode of medical community. We proposed multi-parametric MRI (mpMRI) for those with serum PSA ≥4 ng/ml and suspicious lesions should be scored according to PI-RADS V2. The ultrasound-guided transperineal targeted prostate biopsy was performed for those with PI-RADS ≥3 and those with PI-RADS < 3 but tPSA ≥10 ng/ml. The tPSA follow-up examinations were performed every 6 months for tPSA < 10 ng/ml and PI-RADS < 3 points and once a year for tPSA < 4 ng/ml.Results:Among the 16 007 male population ≥50 years, 2 007(12.54%) were found serum PSA ≥4 ng/ml, and 634(31.59%)were referred to the referral hospital through the medical community system. Combining tPSA and mpMRI, 271 patients underwent ultrasound-guided transperineal targeted prostate biopsy. Among them, 162 were finally diagnosed with PCa, with a biopsy positive rate of 59.78%. The detection rate of PCa in all the subjects was 1.01%. According to the pathological grade, 5(3.08%) were in ISUP group 1, 95(58.64%) in ISUP group 2-3, and 62(38.27%) in ISUP group 4-5. There were 102(62.96%), 39(24.07%) and 21(12.96%) with localized, locally advanced or metastatic PCa, respectively. The levels of tPSA in the four groups were (1.13±1.44)ng/ml, (1.77±3.45)ng/ml, (3.27±17.58)ng/ml, and (4.26±11.48)ng/ml, respectively, with statistically significant differences ( P<0.01). The positive number of biopsy in each group was 1 case(0.06%), 56 cases(0.79%), 81 cases(1.36%) and 24 cases(1.82%) respectively, with statistically significant differences ( P<0.01). The number of ISUP 4-5 grades in each group was 0, 17(30.35%), 29(35.80%), and 16(66.67%) respectively, with statistically significant differences ( P<0.01). Conclusions:Based on the medical community system, according to the tPSA screening results of the primary hospitals, it is feasible and effective to refer suspicious patients to the referral hospitals for mpMRI examination, and screen prostate cancer by ultrasound-guided transperineal prostate fusion biopsy.

BACKGROUND: Large disparities exist in liver cancer burden trends across countries but are poorly understood. We aimed to investigate the global trajectories of liver cancer burden, explore the driving forces, and predict future trends. METHODS: Data on the liver cancer burden in 204 countries and territories from 1990 to 2019 were extracted from the Global Burden of Disease Study. The age-standardized incidence rate (ASIR) and age-standardized mortality rate (ASMR) trajectories were defined using growth mixture models. Five major risk factors contributing to changes in the ASIR or ASMR and socioeconomic determinants were explored using the identified trajectories. A Bayesian age-period-cohort model was used to predict future trends through 2035. RESULTS: Three trajectories of liver cancer burden were identified: increasing, stable, and decreasing groups. Almost half of the American countries were classified in the decreasing group (48.6% for ASIR and ASMR), and the increasing group was the most common in the European region (ASIR, 49.1%; ASMR, 37.7%). In the decreasing group, the decrease of liver cancer due to hepatitis B contributed 63.4% and 60.4% of the total decreases in ASIR and ASMR, respectively. The increase of liver cancer due to alcohol use, hepatitis C, and hepatitis B contributed the most to the increase in the increasing group (30.8%, 31.1%, and 24.2% for ASIR; 33.7%, 30.2%, and 22.2% for ASMR, respectively). The increasing group was associated with a higher sociodemographic index, gross domestic product per capita, health expenditure per capita, and universal health coverage (all P <0.05). Significant variations in disease burden are predicted to continue through 2035, with a disproportionate burden in the decreasing group. CONCLUSION Global disparities were observed in liver cancer burden trajectories. Hepatitis B, alcohol use, and hepatitis C were identified as driving forces in different regions.
Humans ; Bayes Theorem ; Liver Neoplasms ; Risk Factors ; Hepatitis C/complications* ; Hepatitis B ; Hepacivirus ; Incidence

Objective:To investigate the change trend of etiological burden of disease of liver cancer in the Chinese population from 1990 to 2019.Methods:The descriptive epidemiologic method was conducted. Based on the Global Burden of Disease data from the Institute for Health Metrics and Evaluation at the University of Washington, the data related to liver cancer burden caused by hepatitis B virus (HBV) infection, hepatitis C virus (HCV) infection, alcohol, nonalcoholic steatohepatitis (NASH) and other factors, including number of new cases, the crude incidence rate, age-specific incidence rate, number of deaths, crude mortality rate and age-specific mortality rate, in the Chinese population from 1990 to 2019 were collected. The age-standardized rate was calculated based on the world standardized population structure in 2019 from the Global Burden of Disease data. Observation indicators: (1) the incidence of liver cancer caused by different etiologies in the Chinese population from 1990 to 2019; (2) the mortality of liver cancer caused by different etiologies in the Chinese population from 1990 to 2019; (3) the change trend of age-specific incidence rate of liver cancer caused by different etiologies in the Chinese population from 1990 to 2019; (4) the age-specific mortality rate of liver cancer caused by different etiologies in the Chinese population from 1990 to 2019. Count data were expressed as absolute numbers, percentages and ratio. Based on the junction point regression model, the Joinpoint software (V.4.9.1.0) was used to calculate the annual percentage change, average annual percentage change (AAPC) and 95% confidence intervals ( CI) of age-specific incidence rate and age-specific mortality rate of liver cancer caused by different etiologies. Results:(1) The incidence of liver cancer caused by different etiologies in the Chinese population from 1990 to 2019. From 1990 to 2019, the number of new cases of liver cancer in Chinese population decreased from 236 825 to 210 462, and the crude incidence rate decreased from 20.01/100,000 to 14.80/100,000. The new cases of liver cancer caused by HBV infection, HCV infection and other factors showed a downward trend, and the absolute change rates were ?14.76%, ?3.98% and ?26.67%, respectively. The new cases of liver cancer caused by alcohol and NASH showed a increase trend, and the absolute change rates were 9.31% and 13.91%, respectively. (2) The mortality of liver cancer caused by different etiologies in the Chinese population from 1990 to 2019. From 1990 to 2019, the number of deaths of liver cancer in Chinese population decreased from 232 449 to 187 700, and the crude mortality rate decreased from 19.64/100,000 to 13.20/100,000. The number of deaths of liver cancer caused by HBV infection, HCV infection and other factors showed a down-ward trend, and the absolute change rates were ?23.34%, ?10.99% and ?33.75%, respectively. The number of deaths of liver cancer caused by alcohol showed a slow downward trend, and the absolute change rate was ?0.51%. The number of deaths of liver cancer caused by NASH showed a increase trend, and the absolute change rate was 6.03%. (3) The change trend of age-specific incidence rate of liver cancer caused by different etiologies in the Chinese population from 1990 to 2019. From 1990 to 2019, the AAPC of age-specific incidence rate of liver cancer caused by HBV infection, HCV infection, alcohol, NASH and other factors was ?3.61%(95% CI as ?4.10% to ?3.11%), ?3.57%(95% CI as ?3.99% to ?3.14%), ?2.79%(95% CI as ?3.24% to ?2.33%), ?2.65%(95% CI as ?3.09% to ?2.21%) and ?3.62%(95% CI as ?4.05% to ?3.19%), respectively. (4) The age-specific mortality rate of liver cancer caused by different etiologies in the Chinese population from 1990 to 2019. From 1990 to 2019, the AAPC of age-specific mortality rate of liver cancer caused by HBV infection, HCV infection, alcohol, NASH and other factors was ?3.92%(95% CI as ?4.42% to ?3.41%), ?3.90%(95% CI as ?4.45% to ?3.35%), ?3.15%(95% CI as ?3.71% to ?2.58%), ?2.86%(95% CI as ?3.34% to ?2.38%) and ?4.09%(95% CI as ?4.64% to ?3.55%), respectively. Conclusions:From 1990 to 2019, the liver cancer burden of the Chinese population shows an overall downward trend, in which the liver cancer burden caused by HBV and HCV infection decreases the most, but HBV and HCV infection is still the main reason for the heavy burden of liver cancer. The age-specific incidence rate and age-specific mortality rate of liver cancer caused by alcohol and NASH show a downward trend, but the number of new cases of liver cancer caused by alcohol and NASH shows significant growth. The liver cancer burden caused by other factors shows a downward trend.

ObjectiveTo observe the lower limb muscle activation strategy of healthy middle-aged and old women during stair ascent and descent with surface electromyography. MethodsFrom August, 2021 to February, 2022, 20 healthy middle-aged and old women were measured the surface electromyography root mean square (RMS) and integrated electromyography (iEMG) of bilateral vastus lateral, rectus femoris, vastus medialis, biceps femoris and semitendinosus during stair ascent and descent, and co-contraction ratio was calculated. ResultsDuring stair ascent, the RMS of bilateral vastus lateral, rectus femoris and vastus medialis was higher at starting stage than at following stage (|t| > 6.650, P < 0.001), while the RMS of biceps femoris and semitendinosus was lower (t > 3.559, P < 0.01); and the co-contraction ratio of hamstrings/quadriceps was lower at starting stage than at following stage (t > 8.185, P < 0.001). During stair descent, the RMS of bilateral vastus lateral, vastus medialis, biceps femoris and semitendinosus was higher at following stage than at starting stage (t > 2.345, P < 0.05), as well as the co-contraction ratio of hamstrings/quadriceps (t > 2.405, P < 0.05). ConclusionThe activities of the muscles around the knees are almost symmetrical during stair ascent and descent for healthy middle-aged and old women. The activation and co-contraction ratio of quadriceps and hamstring are various at starting/following stages.