An analytical liquid-liquid extraction-gas chromatography–mass spectrometry (LLE-GC-MS) method was established for the determination of genotoxic impurities including methyl methanesulfonate (MMS), ethyl methanesulfonate (EMS) and isopropyl methanesulfonate (IMS) in methanesulfonic acid. An Agilent HP-1MS capillary column (30 m × 0.32 m, 1 μm) was used for separating the analytes by programmed heating with the inlet temperature of 220 °C. Mass spectrometry was operated in positive ion mode, and selective ion monitors were set at m/z 80 for MMS, m/z 79 for EMS, m/z 123 for IMS and m/z 56 for internal standard butyl methanesulfonate (BMS). Results showed that the baseline separation of MMS, EMS and IMS was achieved, and the blank extraction solution had no interference; good linearity was achieved in the range of 37-1 480 ng/mL for three alkyl methanesulfonates; The mean recoveries of MMS, EMS, IMS were 104.99%, 107.26%,108.85%, respectively, with RSD ≤ 4.54%. The established method has the characteristics of specific, sensitive, accurate, stable and good versatility, and has been used for the detection and control of alkyl methanesulfonate impurities in methanesulfonic acid from a variety of manufacturers.

Objective: To investigate the relationship between fine motor skills and executive function in school aged boys with attention deficit hyperactivity disorder (ADHD) aged 6-10 years, so as to provide a reference for promoting executive function. Methods: From November 2022 to May 2021,65 boys with ADHD were recruited from a tertiary hospital in Beijing and a public elementary school in Beijing, and 65 boys with typical development according to age and sex were recruited as controls. Children s fine motor skills were assessed using the movement assessment battery for children, second version (MABC-2), and children s inhibitory control, working memory, and cognitive flexibility were assessed using the Stroop color word test (SCWT), Rey osterrich complex figure test (ROCFT) and trail making test (TMT), respectively. Independent samples t-tests were used to analyze the differences between the two groups, and Pearson correlation analysis and stratified regression analysis were used to explore the relationship between fine motor skills and executive functioning in boys with ADHD. Results: In the fine motor skills test, boys with ADHD scored significantly lower (8.68±3.62) than control boys (11.22±2.27)( t =4.80, P <0.05); in the executive function test, the results of SCWT, ROCFT, and TMT tests were significantly worse in boys with ADHD than in normal boys ( t =-4.53-4.42, P < 0.05). Correlation analysis showed that the fine motor skill scores of boys with ADHD were negatively correlated with the number of word sense errors ( r =-0.35) and color errors ( r =-0.42), and positively correlated with memory scores for delayed structure ( r =0.30) and detail ( r =0.25), which were negatively correlated with TMT-A ( r =-0.34),TMT-B reaction time ( r =-0.26), number of errors ( r =-0.43) ( P <0.05). Stratified regression analysis showed that fine motor skill scores of boys with ADHD were predictive of test results for inhibitory control, working memory and cognitive flexibility, with explanatory rates of 15%, 7%, and 19%, respectively. Conclusion Fine motor skills in boys with ADHD are correlated with executive functions, and fine motor skills could predict inhibitory control, working memory and cognitive flexibility to some extent. The development of fine motor skills in boy with ADHD could promote their executive functions.

Primary hyperoxaluria type Ⅱ (PH2) is an inherited disorder of the glyoxylate metabolism caused by the gene mutation of glyoxylate reductase/hydroxypyruvate reductase (GRHPR). PH2 is characterized by recurrent nephrolithiasis and nephrocalcinosis, which may even progress into end-stage renal disease. Currently, organ transplantation is the only treatment option for PH2, which mainly includes two strategies: kidney transplantation and combined liver and kidney transplantation. Kidney transplantation yields a high risk of recurrence of oxalate nephropathy, which may cause early graft dysfunction. Combined liver and kidney transplantation could mitigate the deficiency of oxalate metabolism, whereas it yields a high risk of graft complications. PH2 is an extremely rare disorder. No consensus has been reached on the indications, surgical selection and perioperative management of organ transplantation for PH2 patients. In this article, the pathogenesis, diagnosis, monitoring and organ transplantation experience of PH2 were reviewed, aiming to divert clinicians' attention to PH2 and provide reference for determining diagnosis and treatment regimens, especially transplantation strategy for PH2 patients.

Objective To describe the status of anxiety and depression in patients with uveitis, and to explore the related factors of quality of life. Methods A total of 126 uveitis patients from September 2015 to March 2016 were investigated with the General Social Population Questionnaire, Life Quality for Diseases with Visual Impairment Scale, Self-rating Anxiety Scale and Beck Depression Inventory. Results There were 126 valid questionnaires, and the effective recovery rate was 96.9％(126/130). The score of Self-rating Anxiety Scale in uveitis patients was (43.49±7.20) points which lower than the standard mark standardized score, and 14.3％ (18/126)of patients were diagnosed with anxiety. The score of Beck Depression Inventory in uveitis patients was (7.50 ± 6.60) points which lower than the standard mark standardized score, 28.6％ (36/126)of patients were diagnosed with depression. The Self-rating Anxiety Scale scores and psychological dimensions of quality of life was negatively correlated (r=-0.310, P<0.01), and the Beck Depression Inventory scores and the average score of the quality of life, the 4 dimensions and total score of quality of life was negatively correlated(r=-0.534--0.240, all P<0.01). The multiple linear regression analysis showed that the related factors of quality of life were score of depression, vision loss, education and gender(P<0.05). Conclusions The incidence of depression and anxiety are both lower in patients with uveitis than general population. The status of quality of life is related to the score of depression, vision loss, education and gender.

Objective: To examine the developmental trajectory of fine motor ability in schoolage children with attention deficit hyperactivity disorder (ADHD) for two years, so as to provide scientific evidence to promote motor development in ADHD children. Methods: From April to June 2019, 31 children aged 6-8 years old were selected from a public elementary school. They were diagnosed with ADHD by two psychiatric professionals according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V) criteria. Additionally, 31 typical developmental children, matched for age, sex and IQ with the ADHD group, were recruited as the control group. Fine motor ability was assessed with tasks of hand manual dexterity in Movement Assessment Battery for Children-2 (MACB-2), and a followup assessment was conducted from April to June 2021. The development changes of fine motor ability between two groups of children were compared by using t test and repeated measures analysis of variance. Results: Between baseline and followup periods after two years, the total score of hand fine motor in the ADHD group did not show significant improvement (7.4±3.0, 8.0±3.4; t=-1.05, P>0.05), while there was a small effect size improvement in typically developing control group (9.5±2.1, 10.5±2.4; t=-2.12, effect size=0.38, P<0.05). Followup after two years, coin/peg throwing scores with dominant hand improved between ADHD group and control group (7.0±3.3, 9.5±3.2; 8.4±2.8, 11.6±1.6) (t=-3.74, -6.33, P<0.01; effect size=0.67, 1.14), with a smaller improvement in the ADHD group. The score for threading beads/threads decreased in between ADHD group and control group (7.9±2.4, 5.8±3.1; 9.2±1.1, 8.2±1.9) (t=3.89, 2.78, P<0.01; effect size=0.70, 0.50), with a greater decrease in the ADHD group. Conclusions The development speed of fine motor ability in children with ADHD aged 6-8 is slow and continues to lag behind normal developmental children. Fine motor development in children with ADHD should be closely monitored, and targeted interventions should be implemented when necessary.

Objective To observe the electromyography characteristics of children's handwriting with attention deficit hyperactivity disorder(ADHD),and explore its electrophysiological mechanism,so as to provide an objective basis for developing non-pharmacological treatment for such children.Methods Between September 2021 and April 2022,29 ADHD children were recruited from an ordinary public primary school and the psychiatric clinic of a class-3 grade-A hospital in Beijing.Among them,25 were boys and 4 were girls,with an average age of 8.21±1.78 years.Meanwhile,23 male and 5 fe-male healthy counterparts were selected with the age gap no more than 6 months.The Delsys wireless surface EMG system was used to collect the electromyographic signals of the abductor pollicis breve,the first dorsal interosseous muscle,the flexor radial carpi motor and the extensor finger muscles dur-ing their writing tasks such as tracing trajectories,writing Arabic numerals 0-9,26 small and capital English letters,Chinese characters one to ten and"Yong".The percentage of the averaged electromyog-raphy(AEMG)of a muscle in the sum value of all measured muscles,and the coefficient of differ-ence were selected to evaluate the muscle contribution rate and the consistency of exertion,respective-ly.Moreover,the independent sample t-test was employed to compare the two different groups with the significance set at α=0.05.Results There was a significant difference in the muscle contribution of abductor pollicis breve and first dorsal interosseous muscles when writing Arabic numerals and that of abductor pollicis breve muscles when writing Chinese characters between ADHD children(27.29%,25.58%and 27.53%)and their healthy counterparts(42.87%,19.96%and 37.13%)(P<0.05).Most muscle differentiation coefficients of ADHD children were higher than 100%,with that of the domi-nant hand radial wrist flexor muscle reaching 270%in the trajectory tracing task.Conclusion Accord-ing to the characteristics of EMG signals,school-age ADHD children show an immature writing pat-tern,including poor stability of writing-related muscles,insufficient control of small finger muscle groups,poor control of hand coordination,and insufficient muscle inhibition of non-dominant hand.It is recommended to conduct the electromyoelectric assessment of handwriting movements in ADHD chil-dren,so as to carry out targeted intervention at an early stage.

【Objective】 To investigate the clinical efficacy and safety of low-dose rituximab combined with dexamethasone in the treatment of refractory ITP (RITP) in children. 【Methods】 A total of 31 RITP children, admitted to the Hematology Department of Kunming Children′s Hospital from January 2016 to December 2019 and agreed to receive low-dose rituximab (100 mg/ time, once a week, for 4 successive weeks) combined with dexamethasone (0.6 mg/kg, once a day, for 4 successive days) were enrolled and studied. Blood routine was monitored every other day during treatment, and adverse drug reactions were recorded. The influence of gender, disease course and age on prognosis was compared by χ² test. 【Results】 1) Among the 31 cases, 11 (35.5%) had platelets >100×10⁹/L after 4 weeks and had no recurrence in 6 months; 9 (29%) had platelets >30×10⁹/L but <100×10⁹/L and had no recurrence in 6 months; 11 (35.5%) showed no recovery of platelets, which were consistently lower than 30×10⁹/L. 2) Rituximab was used in 4 cases (12.9%), 1 case (3.2%) presented with severe drug-induced rashes; Headache, vomiting and elevated blood pressure occurred in 2 cases (6.4%). 1 case (3.2%) presented with laryngeal edema. 3) There was no difference in the total effective rate among different gender, age and disease course (P >0.05). 【Conclusion】 The total effective rate of low-dose rituximab combined with dexamethasone for children with refractory ITP in 6 months is 64.5%, and the adverse reactions are tolerable, so it can be used as a treatment option for children with refractory ITP.

Objective:To explore the application effect of disease-oriented digitalized teaching model in the undergraduate teaching of stomatology.Methods:A total of 34 undergraduate students in clinical medicine from Batch 2018 were selected as the control group 1, 24 undergraduate students in stomatology from Batch 2015 were selected as the control group 2, and 23 undergraduate students in stomatology from Batch 2018 were collected as the experimental group. The two control groups all accepted the traditional teaching mode, and the experimental group accepted the disease-oriented digitalized teaching model. Finally, the teaching effect was evaluated through questionnaire surveys and less difficult oral professional tests. The SPSS 24.0 was used to conduct t test. Results:After accepting this teaching model, students improved their understanding of the concept of "organism" and "disease" ( P<0.05), and they had a positive evaluation of this teaching model. It was found that the tests scores of the experimental group (42.17±1.21) were significantly higher than those of non-dental major students of the same Batch (24.71±1.42) ( P<0.05), with significant differences, while without significant difference between the tests scores of the senior stemmatological students (43.33±1.30) ( P>0.05). Conclusion:This teaching model enables students to establish the concept of "organism" and form a disease-oriented knowledge framework before entering the decentralized professional courses, which may further stimulates the interest of junior students in their majors, and enhances their professional awareness compared with traditional teaching model. It's also a useful exploration for teaching hospitals to conduct teaching activities of junior undergraduates outside the classroom.

ObjectiveTo investigate the developmental characteristics of gross motor skills and executive functions, and the correlation between them in school-age children with attention deficit hyperactivity disorder (ADHD). MethodsFrom November, 2020 to May, 2021, 90 children with ADHD were recruited from Peking University Sixth Hospital and Beijing Haidian Wanquan Primary School, and other 90 children with normal development from this primary school were recruited matched their age and gender. Gross motor skills were assessed with the Test of Gross Motor Development in Children, Third Edition (TGMD-3), and inhibitory control, working memory, and cognitive flexibility were assessed with Stroop Color Words Test (SCWT), Rey-Osterrich Complex Figure Test (ROCFT) and Trail Making Test (TMT), respectively. ResultsThe TGMD-3 score was significantly lower in children with ADHD than in normal children (t = -6.275, P < 0.001), while the test results of SCWT, ROCFT and TMT were worse (|t| ≥ 1.986, P ≤ 0.05). The TGMD-3 score of children with ADHD was negatively correlated with the word sense reaction time (r = -0.261), the number of word sense errors (r = -0.404) and the number of color errors (r = -0.326) (P < 0.05), positively correlated with the delayed structural memory scores (r = 0.228) (P < 0.05), and negatively correlated with the TMT-A reaction time (r = -0.255), the number of TMT-A errors (r = -0.329), TMT-B reaction time (r = -0.214) and the number of TMT-B errors (r = -0.474) (P < 0.05). Stratified linear regression analyses showed that the TGMD-3 score of children with ADHD was significant only in predicting test results for inhibitory control and cognitive flexibility (P < 0.05), with explanations of 8.7% and 22.5%, respectively. ConclusionDevelopments of both gross motor skills and executive function delay in children with ADHD, and there is a relation between them, especially the level of gross motor skills relating to the developments of inhibitory control and cognitive flexibility.

OBJECTIVETo explore the role of silent information regulator 1 (SIRT1) signaling pathway in mediating the effect of dexmedetomidine (DEX) to alleviate postoperative cognitive dysfunction (POCD) in aged rats.

METHODSSeventy-two healthy male Sprague-Dawley rats aged 18-20 months (weighing 500-700 g) were randomized equally into normal control group, POCD model group, DEX pretreatment group, and DEX and SIRT1 inhibitor (EX527) pretreatment group. In the latter 2 groups, DEX (25 μg/kg) was injected intraperitoneally in the rats 30 min before the operation, and normal saline was injected instead in the other 2 groups; in EX527 group, EX527 (1 μg/kg) was injected intravenously 5 min before the operation. In all but the control group, the rats were subjected to laparotomy lasting 30 min, and on days 1, 3, and 5 following the operation, 6 rats were randomly selected from each group for Morris water maze test to evaluate their cognitive functions. Immediately after the test, the rats were sacrificed and the hippocampus was collected for determination of the levels of tumor necrosis factor- (TNF-) and interleukin-6 (IL-6) using ELISA; Western blotting was used to detect the expression of SIRT1 and nuclear factor- κB (NF-κB) in the hippocampal neurons.

RESULTSCompared with the control rats, the rats in POCD group and EX527 group showed significantly prolonged escape latency, decreased frequency of crossing the original platform, increased TNF- and IL-6 levels, lowered SIRT1 expression in the hippocampal neurons, and increased NF-κB expression ( < 0.05), and these parameters were comparable between POCD group and EX527 group ( > 0.05). DEX pretreatment significantly alleviated cognitive dysfunction and attenuated the changes in TNF-, IL-6, SIRT1, and NF-κB expressions induced by the operation ( < 0.05), and EX527 pretreatment of the rats obviously blocked the effects of DEX ( < 0.05).

CONCLUSIONSDEX alleviates POCD in aged rats probably via SIRT1 signaling pathway.