Objective:To investigate the association between blood selenium levels and sex hormones in Chinese men aged 18-79 years.Methods:Data were derived from the China National Human Biomonitoring survey conducted in 2017-2018, with a final sample size of 5 414 men. General demographic characteristics, behavioral habits, and dietary frequency were collected through questionnaires and physical examinations. Fasting blood samples were collected to measure blood lead, serum testosterone, and estradiol levels. Complex sampling linear regression models were used to analyze the associations between blood selenium levels and testosterone, estradiol, and the testosterone/estradiol ratio, adjusting for confounding factors including age, education level, marital status, smoking status, alcohol consumption, seafood intake, soy product intake, protein supplement intake, BMI, and diabetes status.Results:The mean age of the 5 414 participants was (46.85±27.91) years; 4 774 (91.65%) were of Han ethnicity and 4 505 (86.68%) were married. The median ( Q1, Q3) blood selenium concentration in men was 97.80 (80.64, 116.99) μg/L. After adjusting for confounding factors, the complex sampling linear regression model revealed negative associations between blood selenium levels and both testosterone levels and the testosterone/estradiol ratio, with a significant linear trend ( Ptrend<0.05). Compared with the Q1 group, the β (95% CI) values for testosterone in the Q2, Q3, and Q4 groups were -0.02 (-0.06 to 0.02), -0.03 (-0.08 to 0.01), and -0.06 (-0.09 to -0.02), respectively. Similarly, the β (95% CI) values for the testosterone/estradiol ratio in the Q2, Q3, and Q4 groups were -0.01 (-0.03 to 0.02), -0.01 (-0.04 to 0.04), and -0.03 (-0.06 to -0.01), respectively. Subgroup analysis indicated stronger associations between blood selenium levels and testosterone/estradiol levels in non-smoking and obese men (BMI≥28 kg/m2). Conclusion:Blood selenium levels are negatively associated with testosterone levels and the testosterone/estradiol ratio in Chinese adult males.

Body weight abnormalities, including overweight, obesity, and underweight, have become a dual public health challenge in Chinese adults: overweight and obesity lead to a variety of chronic complications, while underweight increases the risks of malnutrition, sarcopenia, and organ dysfunction. To systematically address these issues, multidisciplinary experts in endocrinology, sports science, nutrition, and psychiatry from various regions have held multiple weight management seminars. Based on the latest epidemiological data and clinical evidence, they expanded the guideline to include assessment and intervention strategies for underweight, in addition to the core content of obesity management. This guideline outlines the etiological mechanisms, evaluation methods, and multidimensional management strategies for overweight and obesity, covering key areas such as diagnosis and assessment, medical nutrition therapy, exercise prescription, pharmacological intervention, and psychological support. It is intended to provide a scientific and standardized approach to weight management across the adult population, aiming to curb the rising prevalence of obesity, mitigate complications associated with abnormal body weight, and improve nutritional status and overall quality of life.

Objective:To explore the relationship between urinary cadmium levels and thyroid hormone levels in people aged 40-89 years old in selected areas of China.Methods:Based on the "Investigation of the Impact of Soil Quality of Agricultural Land on Human Health in Typical Areas" project from October 2019 to August 2020, a multi-stage stratified random sampling method was used to include 6 588 middle-aged and older adults aged 40-89. Demographic characteristics, dietary frequency and disease status were collected through the questionnaire and physical examination. Urinary cadmium and urinary creatinine were detected by random midstream urine. Fasting venous blood was collected for the detection of Triiodothyronine (T3) and Thyroxine (T4). The linear mixed effects model was used to explore the association of urine cadmium levels with thyroid hormone levels. Its dose-response relationship was explored by using the restricted cubic spline.Results:The age of the subjects was (63.48±12.18) years, with males accounting for 51.28%. The M ( Q 1,Q 3) of urinary cadmium level, T3 and T4 was 2.48 (1.36, 4.42) μg/g·creatinine, (1.96±0.51) nmol/L and (113.75±29.11) nmol/L, respectively. The linear mixed effects model showed that the changes of T3 and T4 were 0.027 (0.009, 0.044) nmol/L and 2.019 (1.084, 2.953) nmol/L for each one-unit increase (natural logarithm transformed) of urinary cadmium. The restricted cubic spline showed that there was a positive nonlinear association between urinary cadmium and T3 as well as T4 (all Pnonlinear<0.05). Conclusion:In selected areas of China, the urinary cadmium level of middle-aged and older adults aged 40-89 years is positively associated with T3 and T4.

With rapid development of artificial intelligence(AI)technology,its application in basic medical teaching has become more and more extensive,bringing many changes and innovations to medical education.This paper attempts to apply AI to teaching of Medical Immunology,including preparation of teaching resources,teaching practice process,teaching evaluation and other teaching processes,aiming to improve work efficiency of teachers,optimize teaching strategies,improve teaching quality,stimu-late students'enthusiasm for learning,provide new ideas and methods for teaching reform of Medical Immunology,and promote deep integration of AI and basic medical education and teaching.

Background and purpose:Intracellular deubiquitylating enzymes,such as ubiquitin-specific peptidase 2(USP2),play a pivotal role in regulating protein degradation and cellular homeostasis by modulating protein ubiquitin deconjugation,which have been implicated in the proliferation and survival of multiple myeloma(MM)cells.Targeting the inhibition of USP2 activity in MM cells might modulate their biological behavior.This study aimed to investigate regulatory effects of the leukotriene receptor antagonist montelukast sodium on USP2 in MM cells and its subsequent biological effects.Methods:An in vitro deubiquitination reaction system was established using purified USP2 protein and its substrate,the glutathione S-transferase(GST)tagged ubiquitin A-52 residue ribosomal protein fusion product(UbA52),known as GST-UbA52 protein.This system was used to characterize inhibitory effects of montelukast sodium on USP2 deubiquitinase activity.The MM cell lines MM1.S and H929 were used as in vitro models.Cellular thermal shift assay(CETSA)was subsequently employed to test interaction mode between montelukast sodium and USP2 in MM cells.Western blot assay was applied to detect expression levels of USP2 and its targeting regulators,including cell cycle supervisors cyclin D1(CCND1)and cyclin A1(CCNA1),classical signaling transducer KRAS and glucose regulated protein 78kD(GRP78),as well as apoptotic molecule C/EBP-homologous protein(CHOP)in MM1.S and H929 cells before and after the treatment with different concentrations of montelukast sodium.MM cells with either overexpression(H929-OE,MM1.S-OE)or knockdown(H929-LE,MM1.S-LE)of USP2 were generated using a lentiviral vector.Cell counting kit-8(CCK-8)and flow cytometry were utilized to detect the proliferation and apoptotic rates of H929-OE,MM1.S-OE,H929-LE and MM1.S-LE cells treated with montelukast sodium.Results:Montelukast sodium was found to inhibit USP2 mediated degradation of GST-UbA52 protein in a concentration-dependent manner,with a half inhibitory concentration(IC50)of 3.814 μmol/L.Additionally,montelukast sodium significantly enhanced the thermal stability of USP2 at temperatures of 49.1,53.2 and 56.4℃.It was also shown that montelukast sodium could down-regulate expressions of CCND1,CCNA1 and KRAS,while increase levels of GRP78 and CHOP in MM1.S and H929 cells.Furthermore,after treating with 40 μmol/L montelukast sodium for 24 h,the proliferation inhibition and apoptotic rate of H929-OE cells reached to(37.68±1.10)%and(18.99±0.26)%,while the proliferation inhibition and apoptotic rate of MM1.S-OE cells reached to(24.48±0.49)%and(33.29±0.75)%,which were significantly lower than those in H929 and MM1.S cells[H929:(57.19±1.93)%and(45.65±0.24)%;MM1.S:(50.04±0.53)%and(40.25±0.91)%;P＜0.05,n=3].Conversely,the proliferation inhibition and apoptotic rates of H929-LE and MM1.S-LE cells were significantly higher[H929-LE-1#:(80.70±1.60)%and(89.08±0.49)%;H929-LE-2#:(75.30±3.80)%and(82.41±1.07)%;MM1.S-LE-1#:(70.64±0.84)%and(67.63±0.21)%;MM1.S-LE-2#:(68.47±1.32)%and(85.90±0.18)%;P＜0.05,n=3].Conclusion:Montelukast sodium can target ubiquitin proteasome regulator USP2 and inhibit its deubiquitylating activity,which may modulate USP2 directing protein and trigger endoplasmic reticulum stress to induce cell cycle arrest and apoptosis in MM cells.

Background and purpose:Intracellular deubiquitylating enzymes,such as ubiquitin-specific peptidase 2(USP2),play a pivotal role in regulating protein degradation and cellular homeostasis by modulating protein ubiquitin deconjugation,which have been implicated in the proliferation and survival of multiple myeloma(MM)cells.Targeting the inhibition of USP2 activity in MM cells might modulate their biological behavior.This study aimed to investigate regulatory effects of the leukotriene receptor antagonist montelukast sodium on USP2 in MM cells and its subsequent biological effects.Methods:An in vitro deubiquitination reaction system was established using purified USP2 protein and its substrate,the glutathione S-transferase(GST)tagged ubiquitin A-52 residue ribosomal protein fusion product(UbA52),known as GST-UbA52 protein.This system was used to characterize inhibitory effects of montelukast sodium on USP2 deubiquitinase activity.The MM cell lines MM1.S and H929 were used as in vitro models.Cellular thermal shift assay(CETSA)was subsequently employed to test interaction mode between montelukast sodium and USP2 in MM cells.Western blot assay was applied to detect expression levels of USP2 and its targeting regulators,including cell cycle supervisors cyclin D1(CCND1)and cyclin A1(CCNA1),classical signaling transducer KRAS and glucose regulated protein 78kD(GRP78),as well as apoptotic molecule C/EBP-homologous protein(CHOP)in MM1.S and H929 cells before and after the treatment with different concentrations of montelukast sodium.MM cells with either overexpression(H929-OE,MM1.S-OE)or knockdown(H929-LE,MM1.S-LE)of USP2 were generated using a lentiviral vector.Cell counting kit-8(CCK-8)and flow cytometry were utilized to detect the proliferation and apoptotic rates of H929-OE,MM1.S-OE,H929-LE and MM1.S-LE cells treated with montelukast sodium.Results:Montelukast sodium was found to inhibit USP2 mediated degradation of GST-UbA52 protein in a concentration-dependent manner,with a half inhibitory concentration(IC50)of 3.814 μmol/L.Additionally,montelukast sodium significantly enhanced the thermal stability of USP2 at temperatures of 49.1,53.2 and 56.4℃.It was also shown that montelukast sodium could down-regulate expressions of CCND1,CCNA1 and KRAS,while increase levels of GRP78 and CHOP in MM1.S and H929 cells.Furthermore,after treating with 40 μmol/L montelukast sodium for 24 h,the proliferation inhibition and apoptotic rate of H929-OE cells reached to(37.68±1.10)%and(18.99±0.26)%,while the proliferation inhibition and apoptotic rate of MM1.S-OE cells reached to(24.48±0.49)%and(33.29±0.75)%,which were significantly lower than those in H929 and MM1.S cells[H929:(57.19±1.93)%and(45.65±0.24)%;MM1.S:(50.04±0.53)%and(40.25±0.91)%;P＜0.05,n=3].Conversely,the proliferation inhibition and apoptotic rates of H929-LE and MM1.S-LE cells were significantly higher[H929-LE-1#:(80.70±1.60)%and(89.08±0.49)%;H929-LE-2#:(75.30±3.80)%and(82.41±1.07)%;MM1.S-LE-1#:(70.64±0.84)%and(67.63±0.21)%;MM1.S-LE-2#:(68.47±1.32)%and(85.90±0.18)%;P＜0.05,n=3].Conclusion:Montelukast sodium can target ubiquitin proteasome regulator USP2 and inhibit its deubiquitylating activity,which may modulate USP2 directing protein and trigger endoplasmic reticulum stress to induce cell cycle arrest and apoptosis in MM cells.

Objective:To explore the relationship between urinary cadmium levels and thyroid hormone levels in people aged 40-89 years old in selected areas of China.Methods:Based on the "Investigation of the Impact of Soil Quality of Agricultural Land on Human Health in Typical Areas" project from October 2019 to August 2020, a multi-stage stratified random sampling method was used to include 6 588 middle-aged and older adults aged 40-89. Demographic characteristics, dietary frequency and disease status were collected through the questionnaire and physical examination. Urinary cadmium and urinary creatinine were detected by random midstream urine. Fasting venous blood was collected for the detection of Triiodothyronine (T3) and Thyroxine (T4). The linear mixed effects model was used to explore the association of urine cadmium levels with thyroid hormone levels. Its dose-response relationship was explored by using the restricted cubic spline.Results:The age of the subjects was (63.48±12.18) years, with males accounting for 51.28%. The M ( Q 1,Q 3) of urinary cadmium level, T3 and T4 was 2.48 (1.36, 4.42) μg/g·creatinine, (1.96±0.51) nmol/L and (113.75±29.11) nmol/L, respectively. The linear mixed effects model showed that the changes of T3 and T4 were 0.027 (0.009, 0.044) nmol/L and 2.019 (1.084, 2.953) nmol/L for each one-unit increase (natural logarithm transformed) of urinary cadmium. The restricted cubic spline showed that there was a positive nonlinear association between urinary cadmium and T3 as well as T4 (all Pnonlinear<0.05). Conclusion:In selected areas of China, the urinary cadmium level of middle-aged and older adults aged 40-89 years is positively associated with T3 and T4.

Objective:To investigate the association between blood selenium levels and sex hormones in Chinese men aged 18-79 years.Methods:Data were derived from the China National Human Biomonitoring survey conducted in 2017-2018, with a final sample size of 5 414 men. General demographic characteristics, behavioral habits, and dietary frequency were collected through questionnaires and physical examinations. Fasting blood samples were collected to measure blood lead, serum testosterone, and estradiol levels. Complex sampling linear regression models were used to analyze the associations between blood selenium levels and testosterone, estradiol, and the testosterone/estradiol ratio, adjusting for confounding factors including age, education level, marital status, smoking status, alcohol consumption, seafood intake, soy product intake, protein supplement intake, BMI, and diabetes status.Results:The mean age of the 5 414 participants was (46.85±27.91) years; 4 774 (91.65%) were of Han ethnicity and 4 505 (86.68%) were married. The median ( Q1, Q3) blood selenium concentration in men was 97.80 (80.64, 116.99) μg/L. After adjusting for confounding factors, the complex sampling linear regression model revealed negative associations between blood selenium levels and both testosterone levels and the testosterone/estradiol ratio, with a significant linear trend ( Ptrend<0.05). Compared with the Q1 group, the β (95% CI) values for testosterone in the Q2, Q3, and Q4 groups were -0.02 (-0.06 to 0.02), -0.03 (-0.08 to 0.01), and -0.06 (-0.09 to -0.02), respectively. Similarly, the β (95% CI) values for the testosterone/estradiol ratio in the Q2, Q3, and Q4 groups were -0.01 (-0.03 to 0.02), -0.01 (-0.04 to 0.04), and -0.03 (-0.06 to -0.01), respectively. Subgroup analysis indicated stronger associations between blood selenium levels and testosterone/estradiol levels in non-smoking and obese men (BMI≥28 kg/m2). Conclusion:Blood selenium levels are negatively associated with testosterone levels and the testosterone/estradiol ratio in Chinese adult males.

With rapid development of artificial intelligence(AI)technology,its application in basic medical teaching has become more and more extensive,bringing many changes and innovations to medical education.This paper attempts to apply AI to teaching of Medical Immunology,including preparation of teaching resources,teaching practice process,teaching evaluation and other teaching processes,aiming to improve work efficiency of teachers,optimize teaching strategies,improve teaching quality,stimu-late students'enthusiasm for learning,provide new ideas and methods for teaching reform of Medical Immunology,and promote deep integration of AI and basic medical education and teaching.

Body weight abnormalities, including overweight, obesity, and underweight, have become a dual public health challenge in Chinese adults: overweight and obesity lead to a variety of chronic complications, while underweight increases the risks of malnutrition, sarcopenia, and organ dysfunction. To systematically address these issues, multidisciplinary experts in endocrinology, sports science, nutrition, and psychiatry from various regions have held multiple weight management seminars. Based on the latest epidemiological data and clinical evidence, they expanded the guideline to include assessment and intervention strategies for underweight, in addition to the core content of obesity management. This guideline outlines the etiological mechanisms, evaluation methods, and multidimensional management strategies for overweight and obesity, covering key areas such as diagnosis and assessment, medical nutrition therapy, exercise prescription, pharmacological intervention, and psychological support. It is intended to provide a scientific and standardized approach to weight management across the adult population, aiming to curb the rising prevalence of obesity, mitigate complications associated with abnormal body weight, and improve nutritional status and overall quality of life.