Homo- or heterodimeric compounds that affect dimeric protein function through interaction between monomeric moieties and protein subunits can serve as valuable sources of potent and selective drug candidates. Here, we screened an in-house dimeric natural product collection, and panepocyclinol A (PecA) emerged as a selective and potent STAT3 inhibitor with profound anti-tumor efficacy. Through cross-linking C712/C718 residues in separate STAT3 monomers with two distinct Michael receptors, PecA inhibits STAT3 DNA binding affinity and transcription activity. Molecular dynamics simulation reveals the key conformation changes of STAT3 dimers upon the di-covalent binding with PecA that abolishes its DNA interactions. Furthermore, PecA exhibits high efficacy against anaplastic large T cell lymphoma in vitro and in vivo, especially those with constitutively activated STAT3 or STAT3^Y640F. In summary, our study describes a distinct and effective di-covalent modification for the dimeric compound PecA to disrupt STAT3 function.

Objective Prepubertal mice are administered subcutaneously with letrozole sustained-release pellets behind the neck and treated with a high-fat diet to establish a mouse model of polycystic ovary syndrome(PCOS).The liver transcriptomes of the model mice are compared with those of the placebo control mice to investigate the underlying mechanisms of liver involvement in the pathogenesis of PCOS.Methods A customized 2 mg dose of letrozole sustained-release pellets with a 40-day release period was used.The control placebo and letrozole pellets were implanted subcutaneously in the dorsal cervical region of 3-4-week-old C57BL/6J mice(8 mice per group)to establish the control group and letrozole-induced PCOS model group.Both groups were treated with a high-fat diet starting the day after administration.The modeling period lasted for 5 weeks,during which body weight and 24-hour food intake were monitored in each group every week.When samples were collected,liver weight was recorded.Pathological changes in ovarian and hepatic tissues were examined by hematoxylin-eosin(HE)staining,while hepatic lipid deposition was observed by Oil Red O staining.The extent of macrophage infiltration in the liver was evaluated via F4/80 immunohistochemical staining,and hepatic fibrosis levels were observed by Masson's trichrome staining.Transcriptomic sequencing was performed to analyze differentially expressed genes(DEGs)in liver tissues between the control and model groups,followed by enrichment analysis of significant DEGs.Quantitative real-time fluorescent quantitative PCR(qPCR)was subsequently used to validate the expression of significant DEGs in liver tissues of both groups.Results Compared with the control group,the model group which received subcutaneous letrozole sustained-release pellets combined with a high-fat diet exhibited significantly increased body weight(P＜0.001),prominent polycystic ovarian morphology,and significantly decreased liver-to-body weight ratio(P＜0.05).However,no significant changes were observed in absolute liver weight(P＞0.05),hepatic histomorphology,or lipid deposition.Transcriptome sequencing identified 119 upregulated and 217 downregulated DEGs in the liver tissues of letrozole-treated mice,which were predominantly enriched in pathways related to cholesterol and steroid biosynthesis,steroid hormone metabolism,and inflammatory responses.qPCR validation demonstrated that mRNA expression of HSD3B2 and HMGCR was significantly upregulated in liver(P＜0.01),while mRNA expression of IL4,CCL2 and COL1A1 was downregulated(P＜0.05)in the model group compared with the control group.However,Masson's trichrome staining and F4/80 immunohistochemical analysis showed no significant changes in hepatic fibrosis or macrophage infiltration.Conclusion Subcutaneous administration of letrozole sustained-release pellets combined with a high-fat diet successfully establishes a mouse model of PCOS.The model mice exhibited significant changes in hepatic gene expression.Liver may contribute to PCOS pathogenesis through regulating cholesterol and steroid metabolism.

Objective:To establish a pure water direct dilution-inductively coupled plasma mass spectrometry (ICP-MS) detection method for rapid determination of urinary iodine.Methods:Pure water was used to directly dilute the urine samples. The washing solution was 5.0 g/L ascorbic acid, the internal standard solution was 5.0 g/L ascorbic acid and 100 μg/L 128Te, the standard solution was prepared with the solution of lyophilized urine iodine biological component analysis reference material. The method was evaluated in terms of linear range, detection limit, quantification limit, precision and method comparision experiment. Results:The linear correlation coefficient of the standard curve for iodine concentration range from 0 to 50.0 μg/L was 0.999 7, with a detection limit of 0.2 μg/L and a quantification limit of 0.6 μg/L. The spiked recovery rates of low, medium, and high concentration iodine standard solutions added to actual urine samples were 100.8%, 99.1% and 99.7%, respectively, with relative standard deviations of 0.8%, 1.3% and 1.6%, respectively. There was no statistically significant difference ( t = - 0.14, P = 0.890) between the results of measuring actual urine and assessment urine using this method and "Determination of Iodine in Urine-Part 2: Inductively Coupled Plasma Mass Spectrometry (WS/T 107.2-2016)". Conclusions:We have successfully established a pure water direct dilution-ICP-MS method for determining urinary iodine. This method provides accurate and highly sensitive results, making it suitable for sudden public health emergencies and large-scale clinical measurement of urinary iodine.

Objective:To establish a pure water direct dilution-inductively coupled plasma mass spectrometry (ICP-MS) detection method for rapid determination of urinary iodine.Methods:Pure water was used to directly dilute the urine samples. The washing solution was 5.0 g/L ascorbic acid, the internal standard solution was 5.0 g/L ascorbic acid and 100 μg/L 128Te, the standard solution was prepared with the solution of lyophilized urine iodine biological component analysis reference material. The method was evaluated in terms of linear range, detection limit, quantification limit, precision and method comparision experiment. Results:The linear correlation coefficient of the standard curve for iodine concentration range from 0 to 50.0 μg/L was 0.999 7, with a detection limit of 0.2 μg/L and a quantification limit of 0.6 μg/L. The spiked recovery rates of low, medium, and high concentration iodine standard solutions added to actual urine samples were 100.8%, 99.1% and 99.7%, respectively, with relative standard deviations of 0.8%, 1.3% and 1.6%, respectively. There was no statistically significant difference ( t = - 0.14, P = 0.890) between the results of measuring actual urine and assessment urine using this method and "Determination of Iodine in Urine-Part 2: Inductively Coupled Plasma Mass Spectrometry (WS/T 107.2-2016)". Conclusions:We have successfully established a pure water direct dilution-ICP-MS method for determining urinary iodine. This method provides accurate and highly sensitive results, making it suitable for sudden public health emergencies and large-scale clinical measurement of urinary iodine.

Objective Prepubertal mice are administered subcutaneously with letrozole sustained-release pellets behind the neck and treated with a high-fat diet to establish a mouse model of polycystic ovary syndrome(PCOS).The liver transcriptomes of the model mice are compared with those of the placebo control mice to investigate the underlying mechanisms of liver involvement in the pathogenesis of PCOS.Methods A customized 2 mg dose of letrozole sustained-release pellets with a 40-day release period was used.The control placebo and letrozole pellets were implanted subcutaneously in the dorsal cervical region of 3-4-week-old C57BL/6J mice(8 mice per group)to establish the control group and letrozole-induced PCOS model group.Both groups were treated with a high-fat diet starting the day after administration.The modeling period lasted for 5 weeks,during which body weight and 24-hour food intake were monitored in each group every week.When samples were collected,liver weight was recorded.Pathological changes in ovarian and hepatic tissues were examined by hematoxylin-eosin(HE)staining,while hepatic lipid deposition was observed by Oil Red O staining.The extent of macrophage infiltration in the liver was evaluated via F4/80 immunohistochemical staining,and hepatic fibrosis levels were observed by Masson's trichrome staining.Transcriptomic sequencing was performed to analyze differentially expressed genes(DEGs)in liver tissues between the control and model groups,followed by enrichment analysis of significant DEGs.Quantitative real-time fluorescent quantitative PCR(qPCR)was subsequently used to validate the expression of significant DEGs in liver tissues of both groups.Results Compared with the control group,the model group which received subcutaneous letrozole sustained-release pellets combined with a high-fat diet exhibited significantly increased body weight(P＜0.001),prominent polycystic ovarian morphology,and significantly decreased liver-to-body weight ratio(P＜0.05).However,no significant changes were observed in absolute liver weight(P＞0.05),hepatic histomorphology,or lipid deposition.Transcriptome sequencing identified 119 upregulated and 217 downregulated DEGs in the liver tissues of letrozole-treated mice,which were predominantly enriched in pathways related to cholesterol and steroid biosynthesis,steroid hormone metabolism,and inflammatory responses.qPCR validation demonstrated that mRNA expression of HSD3B2 and HMGCR was significantly upregulated in liver(P＜0.01),while mRNA expression of IL4,CCL2 and COL1A1 was downregulated(P＜0.05)in the model group compared with the control group.However,Masson's trichrome staining and F4/80 immunohistochemical analysis showed no significant changes in hepatic fibrosis or macrophage infiltration.Conclusion Subcutaneous administration of letrozole sustained-release pellets combined with a high-fat diet successfully establishes a mouse model of PCOS.The model mice exhibited significant changes in hepatic gene expression.Liver may contribute to PCOS pathogenesis through regulating cholesterol and steroid metabolism.

Objective To assess whether propofol call induce stable psychic dependence in the rats by self-administration experiment. Methods Twenty-four male SD rats 14 weeks old weighing 240一270 mg were studied. Anesthesia was performed with intraperitoneal injection of 3%sodium pentoharbitsl 40 ms/kg and atropine 03 mg/kg.A catheter wag inserted into the right external jugular vein. Penicillin(100 000 U)0.2 ml wag injected through the external jugular vein for anti-infection and heparin sodium(50U/ml)0.1 ml for anticoagulation. The self-administration experiment of 14 days was started after the 7 days of recovery. All the rats were randomly divided into 4 groups(n=6 each):contontrol group(C),propofol 0.56 mg/kg/l group(P1),propofol 1.00 mg/kg group(P2)and pmpofol 1.70 ms/kg group(P3).The experimental events were controlled by a computer with 50 times of the maximum injection per day.The times ofactive and inactive nose-poke response and times of drug iniection were recorded per day.Results Compared with group C and P1,the times of active nosepoke response and injections were significantly increased in group P2 and P3(P<0.01).The times of active nosepoke response and injections per day were significantly increased in group P3 than in group P2(P(0.01).There was no significant difference in the times of active nose-poke response and injections between group C and P1.There was no significant difference in inactive nose-poke resporme between the 4 groups.And the total daily doses of propofol injected in the last 3 days were significantly increased in a dose-dependent manner.Conclusion Propefol can induce the development of psychological dependence in rata and it is related to the dosage.