Objective Biomechanical analyses of straight techniques for Chinese male skaters during the 1 500-m race were conducted to determine the influence of motion techniques on sports performance.Methods Thirty-four male skaters participating in the 1 500-m National Speed Skating Championship race were selected as research subjects.Kinematic characteristics were collected using three-dimensional fixed-point video analysis.The correlations between the periodic characteristics,motion phase characteristics,moment characteristics,and periodic velocity were analyzed.Results The period distance(r=0.560),gliding distance(r=0.554),and push-off distance(r=0.512)showed strong positive correlations with the periodic velocity.The trunk range of motion(ROM)(r=0.651),ankle angle(r=0.434),and ankle ROM(r=0.446)showed moderate or high positive correlations with the gliding velocity.The trunk angle(r=-0.427)showed a moderate negative correlation with the gliding velocity.Additionally,the trunk angle(r=0.673),hip extension angle(r=0.804),abduction angle(r=0.560),and abduction angle speed(r=0.566)were highly positively correlated with the push-off velocity.The push-off angle(r=-0.605)showed a high negative correlation with the push-off velocity.Conclusions The velocity of a straight line in 1 500-m speed skating depends on the dancing distance.Greater gliding and push-off distances result in higher velocities.The trunk and ankle angles significantly influence the gliding velocity,and appropriately increasing the trunk ROM can effectively improve the gliding velocity.The trunk,hip,and push-off angles are key determinants affecting the push-off velocity,and actively extending the hip and pushing-off can effectively enhance the push-off velocity.

【Objective】 To investigate the distribution of ABO and RhD blood groups among voluntary blood donors in Guangzhou, in order to ensure clinical blood safety and better serve blood donors. 【Methods】 Routine ABO and RhD blood group screening tests were carried out among voluntary blood donors from January 2021 to December 2022. The composition ratio of ABO blood group was statistically analyzed. The samples with discrepancy between forward and reverse blood grouping and negative RhD blood group samples were further verified by serological test to analyze the ABO subtypes and the reasons for missed detection. 【Results】 A total of 749 123 blood samples were screened from January 2021 to December 2022, and 513 291 samples were collected after excluding repeat blood donors, with the ABO blood groups as 208 126(40.55%) of O type, 138 859(27.05%) of A type, 130 987(25.52%) of B type and 35 319(6.88%) of AB type. The screening results showed discrepancy between forward and reverse blood grouping in 506 samples, of which 58 were with weak/non-erythrocyte reaction, 16 with erythrocyte reaction, 215 with weak/non-serum reaction, and 217 with serum reaction. Further serological test indicated that 44 samples were ABO subtypes, among which 13 were subtype A, 26 subtype B, 5 subtype AB and 3 B (A) and 14 Bombay-like blood group. The blood group with the highest missed detection rate in repeat blood donors were A3/B3 subtype (68.42%). A total of 128 unexpected antibody positive samples were detected among 513 291 samples A total of 2 277 samples were screened negative for RhD blood type, of which 2 188 were confirmed to be Rh negative (2 188/513 291, 0.43%), 89 were D variants (89/513 291, 0.02%, ) and 30 were detected with unexpected antibodies (30/2 188, 1.37%). 【Conclusion】 The ABO blood group distribution of blood donors in Guangzhou is O>A>B>AB, and the proportion of RhD negative population is 0.43%, slightly highter than 0.3%-0.4% of Han population nationwide. The ABO blood group subtype is dominated by B subtype. The detection rate and missed detection rate of A3/B3 subtypes in routine blood group tests are the highest.

Objective To explore the predictive value of the model for end-stage liver disease (MELD) score, energy metabolism and serum thyroid hormone levels on the severity and prognosis of patients with liver failure and their correlation. Methods This study collected clinicopathological data from 60 liver failure patients, e.g., end-stage liver disease (MELD) score, energy metabolism, and serum thyroid hormone levels. The χ 2 test was performed to analyze the categorical variables, while the Mann-Whitney U test and independent sample t test were performed to assess the continuous variables between the two groups. Spearman correlation coefficient test was used to evaluate correlation of each index. The receiver operating characteristic (ROC) curve was used to analyze the optimal cut-off points of serum total triiodothyronine (TT3) and free triiodothyronine (FT3) levels in predicting prognosis of the patients. Results The rates of low TT3 and FT3 levels in liver failure patients were 78.2% and 69.1%, respectively, whereas the low TT3 rates were 95.2% and 67.6% and the low FT3 rates were 90.5% and 55.9% in survival and non-survival groups of patients, respectively (both P < 0.05). Moreover, the MELD score was significantly higher in the non-survival patients than in survival patients [26.0(21.0-29.0) vs 21.0 (19.0-24.0), Z =-3.396, P =0.001], while TT3 and FT3 levels were significantly lower in the non-survival patients than in the survival patients [0.69(0.62-0.73) vs 0.83(0.69-0.94) and 2.17(1.99-2.31) vs 2.54(2.12-2.86), respectively; Z =-2.884、-2.876, all P < 0.01]. The MELD score was negatively associated with serum TT3, FT3, and thyroid stimulating hormone (TSH) levels and the respiratory quotient (RQ) ( r =-0.487、-0.329、-0.422、-0.350, all P < 0.01), whereas the RQ was associated with serum TT3 and FT3 levels ( r =0.271、0.265, all P < 0.05). The optimal cutoff values in predicting the severity and survival of patients was 0.75 nmol/L and 2.37pmol/L with the sensitivity values of 67.6% and 64.7% and the specificity of 90.5% and 81.0%, respectively. Conclusion Abnormal thyroid hormone levels and low respiratory quotient could be used to predict the severity and prognosis of patients with liver failure.

Objective To investigate the ability of combined baseline serum markers, i.e., HBV DNA, HBV RNA, HBsAg, and HBcrAg, to predict HBeAg seroconversion in patients with HBeAg-positive chronic hepatitis B (CHB) treated by nucleos(t)ide analogues. Methods A retrospective analysis was performed for 83 HBeAg-positive patients selected as subjects from the prospective CHB follow-up cohort established by Difficult & Complicated Liver Diseases and Artificial Liver Center, Beijing YouAn Hospital, Capital Medical University, from June 2007 to July 2008, and the baseline serum levels of HBV DNA, HBV RNA, HBsAg, and HBcrAg were analyzed. The t -test or the Mann-Whitney U test was used for comparison of continuous data between two groups, and the chi-square test was used for comparison of categorical data between two groups. The Spearman method was used for correlation analysis. A Cox regression model was established to calculate HBeAg seroconversion prediction score, and the time-dependent receiver operating characteristic curve was used to evaluate the ability of combined markers in predicting HBeAg seroconversion. The Kaplan-Meier method was used to calculate cumulative seroconversion rate in each group, and the Log-rank test was used for comparison between groups. Results For the 83 HBeAg-positive patients, the median follow-up time was 108 months, and 44.58%(37/83) of these patients achieved HBeAg seroconversion. Compared with the non-seroconversion group, the HBeAg seroconversion group had significantly lower baseline serum levels of HBV DNA [6.23(1.99-9.28) log 10 IU/mL vs 7.69(2.05-8.96) log 10 IU/mL, Z =-2.345, P =0.019] and HBV RNA [4.81(1.40-7.53) log 10 copies/mL vs 6.22(2.00-8.49) log 10 copies/mL, Z =-1.702, P =0.010], and there were no significant differences in the levels of HBsAg and HBcrAg between the two groups ( P > 0.05). The Cox regression equation constructed based on the above serum markers showed a median score of 0.95(range 0.37-3.45) for predicting HBeAg seroconversion. In the total population, the combined score was negatively correlated with HBsAg, HBV DNA, HBV RNA, and HBcrAg ( r =-0.697, -0.787, -0.990, and -0.819, all P < 0.001). Based on the median prediction score, the patients were divided into high HBeAg seroconversion group and low HBeAg seroconversion group; as for the prediction of HBeAg seroconversion rate at 36, 60, and 84 months, the high HBeAg seroconversion group had a seroconversion rate of 43.90%, 51.20%, and 63.10%, respectively, while the low HBeAg seroconversion group had a seroconversion rate of 9.60%, 17.00%, and 19.8%, respectively, and there was a significant difference between the two groups ( χ 2 =11.6, P < 0.001). Conclusion The combined prediction score based on baseline serum HBV markers can predict HBeAg seroconversion in CHB patients treated by nucleos(t)ide analogues.

H 1-antihistamines are widely used in the treatment of various allergic diseases, but there are still many challenges in the safe and rational use of H 1-antihistamines in pediatrics, and there is a lack of guidance on the prescription review of H 1-antihistamines for children.In this paper, suggestions are put forward from the indications, dosage, route of administration, pathophysiological characteristics of children with individual difference and drug interactions, so as to provide reference for clinicians and pharmacists.

Objective To analyze the characteristics of work-related musculoskeletal disorders (WMSDs) among sonographers in Guangdong Province, and to explore the disease pattern of the cases. Methods A total of 512 sonographers from 31 hospitals in Guangdong Province were selected as the research subjects using stratified cluster sampling method. The prevalence of WMSDs in the past year was investigated using the Musculoskeletal Disorders Questionnaire, and the characteristics of WMSDs were analyzed. Latent class analysis was used to identify the disease pattern of WMSDs. Results The overall prevalence of WMSDs was 94.3%. The top five affected body parts were right shoulder, neck, right hand/wrist, lower back and right forearm/elbow, with the prevalence of 80.3%, 75.4%, 61.1%, 55.5% and 45.3%, respectively. The prevalence of WMSDs was higher on the right side for the shoulder, hand/wrist, forearm/elbow, hip/leg and knee compared with the left side (80.3% vs 31.3%, 61.1% vs 13.9%, 45.3% vs 10.0%, 17.4% vs 8.6%, 13.1% vs 8.4%, all P<0.05). The prevalence of WMSDs increased with work years, as well the prevalence of WMSDs in the top five affected body parts among the sonographers (all P<0.05). However, there were no statistical differences in prevalence of WMSDs between general hospitals and maternal and child health hospitals, tertiary hospitals and non-tertiary hospitals, Pearl River Delta hospitals and non-Pearl River Delta hospitals; there was also no statistical difference between different genders and age groups of the sonographers (all P>0.05). The best-fit latent disease pattern for sonographers WMSDs comprised three categories： symptom of neck-right shoulder, symptom of neck-lower back-right shoulder-right elbow-right hand/wrist, and symptom of multi-parts above the knees, with the latent probabilities of 0.438, 0.427 and 0.135, respectively. Conclusion The prevalence of WMSDs in sonographers is extremely high, with a dose-effect relationship with work years. The most common affected parts are neck, lower back and right shoulder, right hand/wrist, and right forearm/elbow. The prevalence of WMSDs in the right side of limb was higher than that in the left. WMSDs primarily occur in multiple parts simultaneously. The most common symptoms occur in the neck-right shoulder and neck-lower back-right shoulder-right elbow-right hand/wrist.

ObjectiveTo investigate the value of MELD 3.0， MELD， and MELD-Na scores in assessing the 90-day prognosis of patients with acute-on-chronic liver failure （ACLF） through a comparative study. MethodsA retrospective analysis was performed for the clinical data of 605 patients with ACLF who were treated in Tianjin Third Central Hospital， The Fifth Medical Center of Chinese PLA General Hospital， and Beijing YouAn Hospital from November 2012 to June 2019， and according to the 90-day follow-up results after admission， they were divided into survival group with 392 patients and death group with 213 patients. The receiver operating characteristic （ROC） curve， the area under the ROC curve （AUC）， net reclassification improvement （NRI）， integrated discrimination improvement （IDI）， and decision curve analysis （DCA） curve were used to investigate the value of MELD 3.0， MELD， and MELD-Na scores at baseline， day 3， week 1， and week 2 in predicting the prognosis of the disease. ResultsAt day 3 and week 1， MELD 3.0 score had an AUC of 0.775 and 0.808， respectively， with a better AUC than MELD score （P<0.05）. At day 3， week 1， and week 2， MELD 3.0 score showed an NRI of 0.125， 0.100， and 0.081， respectively， compared with MELD in predicting the prognosis of ACLF patients， as well as an NRI of 0.093， 0.140， and 0.204， respectively， compared with MELD-Na score in predicting prognosis. At baseline， day 3， week 1， and week 2， MELD 3.0 showed an IDI of 0.011， 0.025， 0.017， and 0.013， respectively， compared with MELD in predicting the prognosis of ACLF patients. At day 3 and week 2， MELD 3.0 showed an IDI of 0.027 and 0.038， respectively， compared with MELD-Na in predicting the prognosis of ACLF patients. All the above NRIs and IDIs were >0， indicating a positive improvement （all P<0.05）. DCA curves showed that MELD 3.0 was superior to MELD at day 3 and was significantly superior to MELD-Na at week 2. There was no significant difference in the ability of the three scores in predicting the prognosis of ACLF patients with different types， and there was also no significant difference in the ability of the three scores in predicting the prognosis of ACLF patients with the etiology of HBV infection， alcohol， or HBV infection combined with alcohol， while MELD 3.0 was superior to MELD for ACLF patients with other etiologies （P<0.05）. ConclusionMELD 3.0 score is better than MELD and MELD-Na scores in predicting the 90-day survival of patients with ACLF， but with limited superiority.

Objective To investigate the expression of autophagy marker in peripheral blood T and B lymphocytes of patients with autoimmune hepatitis (AIH) and its clinical significance. Methods Peripheral blood samples were collected from 62 AIH patients who were treated in Beijing YouAn Hospital affiliated to Capital Medical University from October 2019 to October 2020 who were treated in Beijing YouAn Hospital affiliated to Capital Medical University from October 2019 to October 2020 and 8 healthy controls to detect autophagy of T and B lymphocyte subsets, and then subgroup analyses were performed based on treatment, diagnostic type, and presence or absence of liver cirrhosis and liver failure. The t -test was used for comparison of normally distributed continuous data between two groups; the Kruskal-Wallis H test was used for comparison of non-normally distributed continuous data between multiple groups, and the Mann-Whitney U test was used for comparison between two groups; the chi-square test or the Fisher's exact test was used for comparison of categorical data between two groups. Results Compared with the healthy control group, the AIH group had a significantly higher mean fluorescence intensity (MFI) of the autophagy marker LC3B in CD4 + T, CD8 + T, CD19 + B, and CD4 + CD25 + T lymphocytes (all P < 0.05), especially in CD19 + B lymphocytes. The non-treatment group and the partial remission group had a significantly higher MFI of autophagy marker in CD19 + B lymphocytes than the complete remission group ( P =0.037 and 0.040); the idiopathic AIH (I-AIH) group and the drug-induced AIH(DI-AIH) group had a significantly higher MFI than the primary biliary cholangitis (PBC)-AIH overlap syndrome group ( P =0.037 and 0.031); the non-cirrhosis group and the decompensated cirrhosis group had a significantly higher MFI than the compensated cirrhosis group ( P =0.009 and 0.003); the liver failure group had a significantly higher MFI than the non-liver failure group ( P =0.042). The PBC-AIH group had a significantly higher MFI of autophagy marker in CD4 + CD25 + T lymphocytes than the I-AIH group and the DI-AIH group ( P =0.042 and 0.044), the compensated cirrhosis group had a significantly lower MFI than the non-cirrhosis group ( P =0.037), and the non-liver failure group had a significantly higher MFI than the liver failure group ( P =0.043). Conclusion AIH patients have a significant increase in the expression of autophagy marker in peripheral blood T and B lymphocyte subsets compared with healthy individuals, and the level of autophagy is associated with treatment, diagnostic type, and disease severity.

Objective To investigate the differences in UGT1A1 gene mutation sites, haplotypes, and diplotypes between patients with Gilbert syndrome (GS) and those with Crigler-Najjar syndrome type Ⅱ (CN-2). Methods A retrospective analysis was performed for the clinical data of 138 patients with GS or CN-2 who attended Beijing YouAn Hospital, Capital Medical University, from January 1, 2010 to December 31, 2019, with 109 patients in the GS group and 29 patients in the CN-2 group, and the differences in mutation sites were analyzed between the two phenotypes. The Mann-Whitney U test was used for comparison of continuous data between two groups, and the chi-square test or the Fisher's exact test was used for comparison of categorical data between groups. SNPStats software was used to perform linkage disequilibrium (LD) and haplotype analyses of mutation sites. Strong LD was defined as both | D ′| and r 2 > 0.8, and moderate LD was defined as | D ′| > 0.8 and r 2 > 0.4. Results UGT1A1 gene detection was performed for all patients, and mutations mainly included -3279T > G mutation (104 patients, 75.36%) and -3152G > A mutation (82 patients, 59.42%) in the upstream promoter PBREM region, a promoter TATA box TA insertion mutation (88 patients, 63.77%), and c.211G > A mutation in Exon 1 of the coding region (66 patients, 47.83%). Compared with the CN-2 group, the GS group had a significantly higher proportion of PBREM region -3279T > G mutation (82.57% vs 48.28%, χ 2 =14.508, P < 0.001), PBREM region -3152G > A mutation (68.81% vs 24.14%, χ 2 =18.955, P < 0.001), and promoter TATA box (TA) 6 > (TA) 7 mutation (72.48% vs 31.03%, χ 2 =17.027, P < 0.001), and compared with the GS group, the CN-2 group had a significantly higher proportion of mutations at the c.211 locus (68.97% vs 42.20%, χ 2 =6.575, P =0.010) and the c.1456 locus (51.72% vs 7.34%, χ 2 =29.372, P < 0.001). LD analysis of different mutation sites of the UGT1A1 gene showed strong LD (| D ′| > 0.8, r 2 > 0.8) between (TA) 6 > (TA) 7 and -3152G > A and moderate LD (| D ′| > 0.8, r 2 > 0.4) between (TA) 6 > (TA) 7 and -3279T > G, between -3152G > A and -3279T > G, between (TA) 6 > (TA) 7 and c.211G > A, and between -3279T > G and c.211G > A. Haplotype frequency analysis showed that compared with the CN-2 group, the GS group had a significantly higher frequency of haplotype -3279G—-3152A—(TA) 7 (45.72% vs 17.24%, χ 2 =7.833, P =0.005) and significantly lower frequencies of c.1456G (4.10% vs 16.48%, χ 2 =4.873, P =0.027) and c.211A—c.1456G (1.86% vs 24.90%, χ 2 =15.210, P < 0.001). The diplotype analysis showed that diplotypes consisting of haplotype c.1456G or c.211A—c.1456G were associated with a higher level of total bilirubin (TBil). Conclusion There are differences in common mutation sites and major haplotypes of the UGT1A1 gene between patients with GS and those with CN-2, and the common diplotypes of CN-2 correspond to a higher level of TBil.

Hepatitis, Autoimmune ; Humans ; Liver Failure ; Prognosis