ObjectiveTo prepare a recombinant PETase with a dual-catalytic-triad and to evaluate its efficiency in the biodegradation of polyethylene terephthalate （PET）. MethodsBased on the crystal structure of wild-type PETase， point mutations （T88H/L117D） were introduced via site-directed mutagenesis. The recombinant protein was prepared using prokaryotic expression and chromatography purification techniques. The enzymatic hydrolysis of the mutant PETase was assessed by relatively quantifying the products mono （2-hydroxyethyl） terephthalate （MHET） and terephthalic acid （TPA）. ResultsBoth wild-type and mutant PETases accumulated as inclusion bodies， accounting for approximately 20% of the total bacterial protein. After solubilization in urea， the proteins were eluted at 300 mmol/L imidazole during affinity chromatography purification， with concentrations of 1.824 and 1.833 mg/mL and purities of 83.11% and 84.32%， respectively. Subsequent anion-exchange chromatography yielded highly pure enzymes in the 200 mmol/L NaCl fraction： 2.776 mg/mL （96.86% purity） for the wild type and 1.967 mg/mL （95.13% purity） for the mutant. Following refolding， the final concentrations were 0.484 mg/mL for the wild type and 0.991 mg/mL for the mutant. Hydrolysis assays revealed that the mutant released MHET and TPA at （237.67±17.00）% and （197.33±12.01）% of the wild-type levels， respectively. ConclusionThe T88H/L117D dual-catalytic-triad PETase is successfully prepared and it significantly enhanced PET-degrading activity， thus， it′s a promising biocatalyst for PET bioremediation.

Objective:To observe the effect of Guilu Taohong Formula on semen quality in varicocele(VC)models of rats,and to explore its possible mechanism.Methods:Forty-eight male SD rats were randomly divided into four groups(sham group,model group,Guilu Taohong Formula group and L-carnitine group).After the establishment of models,the rats were treated with intra-gastric administration for eight consecutive weeks.The general condition of the rats was observed.After the gavage,the testicular and epididymal indices were calculated.Semen quality was assessed using an automatic semen analyzer.Apoptosis of testicular cells was assessed by TUNEL staining.And the expression levels of B-cell lymphocytoma-2(Bcl-2),Bcl-2-associated X protein(Bax)and cys-teine aspartate protease-3(caspase-3)in testicular tissue were detected by Western blot.Results:Compared with the sham group,testicular index,epididymal index,sperm concentration,the percentage of progressive motility of sperm(PR％)and the expression level of Bcl-2 decreased in model group(P＜0.01).An increased apoptosis rate of spermatogenic cells and the expression levels of Bax and caspase-3 proteins were observed in model group as well(P＜0.01).Compared with the model group,the testicular index,epidid-ymal index,sperm concentration,PR％and the expression level of Bcl-2 in Guilu Taohong Formula group increased significantly(P＜0.05,P＜0.01).A decreased apoptosis rate of spermatogenic cells and the expression levels of Bax and caspase-3 proteins were de-tected in Guilu Taohong Formula group as well(P＜0.01).Similarly,the L-carnitine group showed increased testicular index,epidid-ymal index,sperm concentration,PR％and the expression level of Bcl-2 protein(P＜0.05,P＜0.01),where showed decreased ap-optosis rate of spermatogenic cells and the expression levels of Bax and caspase-3 proteins compared with model group(P＜0.01,P＜0.05).Conclusion:Guilu Taohong Formula improves semen quality in VC model rats and reduces the apoptosis rate of spermato-genic cells in testicular tissue,which may be related to the promotion of Bcl-2 protein expression and the inhibition of Bax and caspase-3 protein expression levels.

Parathyromegaly refers to chronic enlargement of the parathyroid glands caused by multiple etiological factors. Pathological conditions, such as hyperparathyroidism, parathyroid hyperfunction, parathyroid adenoma, parathyroid cysts, and parathyroid carcinoma may all lead to parathyromegaly. Notably, calcium intake insufficiency and/or vitamin D insufficiency (CVI), which is the predominant etiology of parathyromegaly, now has been recognized as a global public health challenge. Chronic CVI induces negative calcium balance and relative low serum calcium level, stimulating compensatory parathyroid hyperplasia and enlargement. This progression triggers parathyroid hyperfunction and secondary hyperparathyroidism, resulting in bone mass loss, height reduction, kyphosis, osteoporosis, pathological fractures, metastatic vascular calcification and systemic abnormal calcium migration and calcinosis (such as urolithiasis). During the early stages of parathyromegaly, the condition remains preventable and treatable; However, delayed intervention may lead to irreversible tertiary hyperparathyroidism. CVI-associated parathyromegaly exhibits high prevalence and heterogeneous clinical manifestations, representing a critically underrecognized clinical entity. This article will systematically discuss the etiology, pathological characteristics, clinical consequences, and prevention and control strategies for CVI-related parathyromegaly.

Patients with initially diagnosed breast cancer and uncontrolled hyperthyroidism are at high risk of perioperative thyroid crisis. This article reports two cases of early-stage breast cancer initially diagnosed concurrently with uncontrolled primary hyperthyroidism. In Case 1, the patient received neoadjuvant chemotherapy to control breast cancer progression while concurrently taking antithyroid drugs to manage hyperthyroidism. Hyperthyroidism was controlled during chemotherapy, and the patient successfully underwent surgery after neoadjuvant chemotherapy. Case 2 involved recurrent primary hyperthyroidism with leukopenia after antithyroid drug therapy. Since leukopenia is a relative contraindication for antithyroid drugs, the patient underwent radioactive iodine therapy (iodine-131) and endocrine therapy for one month before proceeding with breast cancer surgery. Through a literature review, this article analyzes preoperative management strategies for uncontrolled hyperthyroidism in initially diagnosed breast cancer patients, emphasizing the importance of normalizing thyroid function to prevent thyroid crisis and reduce perioperative risks.

Aim To observe the interventional effects of Polygala fallax Hemsl.(PFH)on diabetic kidney disease(DKD)rats and the regulatory mechanism of ferroptosis.Methods Thirty-six SD rats were ran-domly divided into the control group,DKD group,fer-rostatin-1(Fer-1)group,PFH-L group,PFH-M group,and PFH-H group,with six rats in each group.Model-ing was induced by a one-time intraperitoneal injection of 35 mg·kg-1 streptozocin(STZ)in combination with high-sugar and high-fat feed.Ferrostatin-1(25μmol·kg-1)was injected intraperitoneally in Fer-1 group.The PFH-L,PFH-M,and PFH-H groups were gavaged with 50,100 and 200 mg·kg-1 of alcoholic extracts of PFH respectively,and the control and DKD groups were gavaged with an equal volume of distilled water once a day for eight weeks.At the end of drug administration,blood glucose,24h-UP,BUN and Scr levels were measured in each group of rats.HE stai-ning and Masson staining were used to observe renal histopathological changes.ELISA was employed to de-termine the levels of total iron,MDA and GSH activity.IHC was used to observe the expression of Nrf2,SLC7A11,and GPX4 in renal tissues.Western blot was used to detect the protein expression of COL1A1,α-SMA,TGF-,FTH-1,TFR-1,Nrf2,SLC7A1 1,GPX4,in renal tissues.RT-qPCR was used to detect the ex-pression levels of Nrf2,SLC7A11,GPX4 mRNA in re-nal tissues.Results Compared with the control group,blood glucose,24h-UP,BUN,Scr increased(P＜0.05);glomerular volume increased,tubular dilata-tion and collagen fiber deposition were obvious;total i-ron,MDA content increased and GSH activity de-creased(P＜0.05);there was increased protein ex-pression of COL1A1,α-SMA,TGF-β,TFR-1 and de-creased protein expression of FTH-1(P＜0.01);there was decreased mRNA and protein expression of Nrf2,SLC7A11,GPX4 in DKD group rats(P＜0.01).Compared with the DKD group,blood glucose,24h-UP,BUN and Scr decreased(P＜0.05);renal tissue le-sions were significantly reduced;total iron and MDA content decreased,and GSH activity increased(P＜0.05);COL1A1,α-SMA,TGF-β,and TFR-1 protein expression decreased and FTH-1 protein expression in-creased(P＜0.05,P＜0.01);Nrf2,SLC7A11,GPX4 mRNA and protein expression increased in Fer-1 and PFH dose groups(P＜0.05,P＜0.01).Conclusions PFH attenuates renal histopathological injury in DKD rats,and the mechanism may be related to the regula-tion of the Nrf2/SLC7A11/GPX4 signaling pathway.

Objective:To explore the mediating effect of psychological resilience between perceived stress and job burnout among standardized gastroenterology nursing training students.Methods:A total of 156 nursing trainees who received standardized training in the Department of Gastroenterology at Shaanxi Provincial People's Hospital between December 2022 and July 2024 were selected by the convenience sampling method. Data were collected using a general information questionnaire, the Connor-Davidson Resilience Scale, the Chinese Perceived Stress Scale, and the Maslach Burnout Inventory-General Survey. A Pearson correlation analysis was used to examine the relationship among perceived stress, psychological resilience, and job burnout in standardized gastroenterology nursing training students. AMOS 24.0 statistical software was used to construct a structural equation model to analyze the mediating effect of psychological resilience between perceived stress and job burnout in standardized gastroenterology nursing training students. The bias-corrected bootstrap method was applied to test the mediating effect of psychological resilience.Results:The averaged total scores of 156 standardized gastroenterology nursing training students were (29.89±0.30) for perceived pressure, (62.45±2.44) for psychological resilience, and (57.85±3.44) for job burnout. Of the trainees, 88 (56.41%) exhibited job burnout, including 39 (25.00%) with mild burnout, 41 (26.28%) with moderate burnout, and 8 (5.13%) with severe burnout. The Pearson correlation analysis showed that perceived stress was positively correlated with job burnout ( r=0.543, P<0.05) and negatively correlated with psychological resilience ( r=-0.443, P<0.05), and psychological resilience was negatively correlated with job burnout ( r=-0.478, P<0.05). The results of bias-corrected bootstrap test showed that psychological resilience had a partial mediating effect between perceived stress and job burnout among standardized gastroenterology nursing training students ( P<0.05), accounting for 32.63% of the total effect. Conclusions:Moderate job burnout was observed in standardized gastroenterology nursing training students. Job burnout was closely related to perceived stress and psychological resilience. Psychological resilience partly mediated the relationship between perceived stress and job burnout. Therefore, clinical managers may alleviate the perceived psychological pressure and subsequently reduce the occurrence of job burnout among standardized nursing training students by increasing psychological resilience.

Transoral endoscopic thyroidectomy vestibular approach(TOETVA)has become a research hotspot because of its cosmetic advantages of no scar on the body surface,but there is still a risk of unique complications,among which mandibular sensory dysfunction is the most common,mainly related to mental nerve injury.This review focuses on the key anatomical structures closely related to the establishment of TOETVA space and the occurrence of complications.A deep understanding of the related anatomical structures of maxillofacial region and neck,especially the location and variation of mental nerve,the course of mandibular marginal branches of facial nerve,the level of mandibular muscles and the adjacent relationship of blood vessels,is the key to safely implement TOETVA and reduce postoperative complications.Preoperative image evaluation,intraoperative precise anatomy,following the design of safe area and improving the operation method in the future will contribute to the further promotion of this operation.

Objective:To explore the value of using computed tomography(CT)values to distinguish fresh and old fractures vertebral bodies in osteoporotic vertebral compression fractures(OVCF).Methods:Retrospective analysis of clinical data of 101 OVCF patients in our hospital from September 2022 to September 2023.Kappa test for consistency between magnetic resonance imaging(MRI)and vertebral CT values in distinguished fresh or old OVCF.The difference of CT values between fresh,old fractures and adjacent normal vertebral bodies were compared.The diagnostic efficiency was analyed by receiver operating characteristic(ROC)curve.Results:There was a high consistency between vertebral CT values and MRI in the diagnosis of OVCF in fresh and old fractures(Kappa value=0.934).There was a difference in difference of CT values between adjacent normal vertebral bodies and fresh fractures vertebral bodies(P＜0.05).There was a difference in difference of CT values of fresh fractures vertebral bodies and old fractures vertebral bodies(P＜0.05).The ROC curve analysis results showed that,the combined measurement of CT values of fresh and old fractured vertebral bodies has an area under the curve(AUC)of 0.723,which was higher than alone measurement of the CT values of fresh fractured vertebral bodies and old fractured vertebral bodies of 0.536 and 0.610(Z=2.548,2.605,2.841,P＜0.05).Conclusion:CT values of vertebral bodies show high consistency in distinguish fresh and old fractures of OVCF compared to MRI findings,and the diagnostic efficiency of combine detection is relatively high.

Objective:To explore the diagnostic value of conventional computed tomography(CT)combined with enhanced CT scan in bone metastases.Methods:This study was a retrospective observational study,84 suspected bone metastases patients admitted to our hospital from January 2022 to August 2024 were selected,All patients underwent conventional CT and enhanced CT scan and pathological examination,Using pathological examination results as the"gold standard"for diagnosis.The imaging manifestations of bone metastases using conventional CT combined with enhanced CT scan examination were observed;The detection rate and bone metastases types of conventional CT and enhanced CT scan were analyzed;The bone metastases location in different types of malignant tumors were analyzed;The detection results of bone metastases between conventional CT and enhanced CT scan were compared;the diagnostic efficacy of conventional CT and enhanced CT scan alone and in combination for bone metastases were analyzed by Receiver operating characteristic(ROC)curve.Results:The detection rate of osteogenic,osteolytic,cystic and mixed bone metastases by conventional CT combined with enhanced CT scan was supered to that of conventional CT and enhanced CT scan alone(P＜0.05).Bone metastases from lung cancer,breast cancer and other tumors mainly occur in the spine,limbs and ribs,while esophageal cancer,gastric cancer,liver cancer,prostate cancer,thyroid cancer,renal cancer,and nasopharyngeal cancer had relatively fewer bone metastases.The positive detection cases of bone metastases used conventional CT combined with enhanced CT scan were supered to those used conventional CT and enhanced CT scan alone.The sensitivity,specificity and accuracy of conventional CT combined with enhanced CT scan for the diagnosis of bone metastases were 94.00％,94.11％and 94.04％,respectively,and the positive/negative predictive values were 95.91％and 91.42％,respectively.The sensitivity,specificity and accuracy of conventional CT scan were 84.00％,78.78％and 80.95％,respectively,and the positive/negative predictive values were 85.71％and 74.28％,respectively.The sensitivity,specificity and accuracy of enhanced CT were 89.79％,85.71％and 88.09％,respectively.and the positive and negative predictive values were 89.79％and 85.71％,respectively.The diagnostic efficacy of conventional CT combined with enhanced CT scan for bone metastases was significantly better than that of conventional CT and enhanced CT scan alone.Conclusions:Conventional CT combined with enhanced CT scan can significantly improve the diagnostic efficiency of bone metastases,and provide an important basis for clinical treatment.

Parathyromegaly refers to chronic enlargement of the parathyroid glands caused by multiple etiological factors. Pathological conditions, such as hyperparathyroidism, parathyroid hyperfunction, parathyroid adenoma, parathyroid cysts, and parathyroid carcinoma may all lead to parathyromegaly. Notably, calcium intake insufficiency and/or vitamin D insufficiency (CVI), which is the predominant etiology of parathyromegaly, now has been recognized as a global public health challenge. Chronic CVI induces negative calcium balance and relative low serum calcium level, stimulating compensatory parathyroid hyperplasia and enlargement. This progression triggers parathyroid hyperfunction and secondary hyperparathyroidism, resulting in bone mass loss, height reduction, kyphosis, osteoporosis, pathological fractures, metastatic vascular calcification and systemic abnormal calcium migration and calcinosis (such as urolithiasis). During the early stages of parathyromegaly, the condition remains preventable and treatable; However, delayed intervention may lead to irreversible tertiary hyperparathyroidism. CVI-associated parathyromegaly exhibits high prevalence and heterogeneous clinical manifestations, representing a critically underrecognized clinical entity. This article will systematically discuss the etiology, pathological characteristics, clinical consequences, and prevention and control strategies for CVI-related parathyromegaly.