Huperzine A is a promising drug to treat Alzheimer's disease (AD). To date, its biosynthetic pathway is still unknown. Lysine decarboxylase (LDC) has been proposed to catalyze the first-step of the biosynthesis of huperzine A. To identify and characterize LDCs from Huperzia serrata, we isolated two LDC fragments (LDC1 and LDC2) from leaves of H. serrata by RT-PCR and then cloned them into pMD 19-T vector. Sequence analysis showed that LDC1 and LDC2 genes shared 95.3% identity and encoded the protein of 212 and 202 amino acid residues respectively. Thus, we ligated LDC genes into pET-32a(+) to obtain recombinant expressing vectors pET-32a(+)/LDC1 and pET-32a(+)/LDC2 respectively. We further introduced two expression vectors into Escherichia coli BL21(DE3) and cultured positive colonies of E. coli in liquid LB medium. After inducing for 4 hours with 260 μg/mL IPTG at 30 degrees C, soluble recombinant Trx-LDC1 and Trx-LDC2 were obtained and isolated for purification using a Ni-NTA affinity chromatography. We incubated purified recombinant proteins with L-lysine in the enzyme reaction buffer at 37 degrees C and then derived the reaction products using dansyl chloride. It was found that both Trx-LDC1 and Trx-LDC2 had decarboxylase activity, could convert L-lysine into cadaverine by way of thin layer chromatography assay. Further, bioinformatics analysis indicated that deduced LDC1 and LDC2 had different physicochemical properties, but similar secondary and three-dimensional structures.
Carboxy-Lyases ; biosynthesis ; genetics ; Cloning, Molecular ; Escherichia coli ; metabolism ; Genetic Vectors ; Huperzia ; enzymology ; genetics ; Lysine ; metabolism ; Plant Proteins ; biosynthesis ; genetics ; Recombinant Proteins ; biosynthesis ; genetics

Dental composite resin is a kind of material which has been widely used in dental restoration. Research has found that the influence of residual monomer on the material mechanical, chemical and biological properties cannot be ignored. This paper elaborates these harms of residual monomers. The effects of resin matrix, inorganic filler and initiating system, illumination, secondarily treatment on the degree of conversion were also analyzed. The paper also discusses the effective measures to increase the conversion, and offers theoretical basis for the clinical application and development of composite resin.
Acrylic Resins ; Composite Resins ; Humans ; Light ; Polymers ; Polyurethanes

ObjectiveTo investigate the family history of other cancers in Chinese han women with familial or sporadic breast cancer.Methodswe analyzed the clinical date of 4 847 primary breast cancer patients cancer patients were treated at the Breast Cancer,Peking University Cancer Hospital between October 2003 and February 2011,among them,465 were familial and4 382 were sporadic breast cancer patients.The differences of family history of cancers other than breast or ovarian cancers were compared between the patients with familial breast cancer and sporadic breast cancer.Results The proportion of cancers other than breast or ovarian cancers in familial breast cancer patients was significantly higher than that in sporadic breast cancer patients(29.7％ vs 20.8％,odds ratio 1.61,P＜ 0.001).Furthermore,the proportion in pancreatic cancer,prostate cancer,and renal cancer in familial breast cancer patients was significantly higher than that of sporadic breast cancer patients ( pancreatic cancer:2.2％ vs 0.8％,P =0.002 ; prostate cancer:1.5％ vs 0.3％,P ＜ 0.001 ; renal cancer:1.1％ vs 0.4％,P =0.03,respectively).And the relative risks of pancreatic cancer,prostate cancer,and renal cancer in the familial breast cancer patients were 2.90-fold,6.07-fold,and 2.97-fold higher than that of sporadic breast cancerpatients,respectively.ConclusionsOur results suggest that the relative risk of cancer other than breast or ovarian in familial breast cancer patients is significantly higher than that in sporadic breast cancer patients,especially pancreatic cancer,prostate cancer,and renal cancer.

Objective To investigate the clinical value and experience of transperitoneal and retroperitoneal robot-assisted partial nephrectomy for renal hi1 ar tumors.Methods We evaluated 48 patients who had partial nephrectomy for renal hilar tumor by robotic surgical syestem from January 2013 to March 2017.In those cases,35 were male and 13 were female,with an average age of 57.3 (range from 41 to 75 ),27 cases were ventral tumor and 21 cases were dorsal tumor.3 cases were totally confined to the renal parenchyma,the other 45 cases were partially confined to the renal parenchyma.18 cases were performed surgery by retroperitoneal route,the rest 30 cases were performed by peritoneal route.Results A total of 48 patients underwent successful robotic partial nephrectomy for renal hilar tumors.The mean warm ischemia time was 22 minutes (range from 16 to 33 minutes) and the mean estimated blood loss was 88 md (range from 50 to 350 ml).No bleeding-related complications were found.Histopathology confirmed 39 cases of ccRCC,7 cases of angioleiomyolipoma,2 cases of renal oncocytoma.There was one case in this review was positive surgical margin (2.1％) and found no sign of recurrence during the short term post-operation follow-up.All cases in this review are following up after surgery to date from 2 months to 4 years,no cases of tumor recurrence or metastasis were found.Conclusions The application of transperitoneal and retroperitoneal RAPN is the effective and safe way for renal hilar tumor resection,and it has a clear advantage of renal surgical incision stitching and tumor complete resection.The choice of surgical approaches depends on the size and location of tumor and the clinical experience of the surgeon.

In recent years, with the in-depth study of PD-1 and PD-L1 and the development of immunotherapy, the first problem is how to screen the beneficiaries. Recent clinical studies have shown that the expression level of PD-L1 in circulating tumor cells (CTC) can be used as a potential biomarker to play a guiding role in immunotherapy of malignant tumors. This article reviews the latest clinical research progress on the expression of PD-L1 in circulating tumor cells in various solid tumors.

Objective To evaluate the efficacy of one stage anterior debridement combined with posterior pedicle screw fixation in the treatment of cervical intervertebral space infection.Methods From June 2010 to June 2016,28 cases were fixed by anterior debridement combined with the posterior vertebral pedicle screws for the cervical intervertebral space infection,19 males and 9 females.The average age was 45-74 years (58±14.5 years old).21 cases (75％) were spontaneous infection,of which 6 cases were diabetes mellitus,15 cases were over 60 years old.The remaining 7 cases (25％) were intervertebral space infection after radiofrequency ablation of the cervical spine.All patients were excluded from tuberculosis and Brucella infection.All patients underwent hematological examination,with emphasis on WBC,ESP and CRP.All patients received JOA score before operation,applied antibiotic according to blood culture and drug sensitive test.All patients underwent one stage anterior debridement combined with posterior pedicle screw fixation,and the operative time and bleeding volume were recorded.After the operation,intravenous antibiotic therapy was continued,and the application of antibiotics was guided according to the results of ESP and CRP,and the time for the application of antibiotics was recorded.Follow up was performed at 3 months,6 months and 1 years after operation respectively.The JOA score and postoperative cervical lordosis Cobb angle were recorded.Results All operations were successfully completed in this group.The operation time was 130-225 min,with an average of 145.5±12.7 min.The intraoperative blood loss was 40-100 ml,with an average of 67±35.2 ml.The incision was healed in one stage.The time of application of antibiotics in 28 patients was 21-87 days,with an average of 30.8±8.7 days.The longest application time of antibiotics was 87 days,and no relapse was found during follow-up.The postoperative JOA score increased from 11.3± 1.2 to three months 14.9 ± 1.96 postoperatively and 6 months 15.1 ± 1.55 and 1 years 16.5±0.48 after operation.The JOA score was significantly higher than that before operation.No significant loss and change of the Cobb angle in the cervical spine surgery were found.All cases had good bone graft fusion at 1 years.Conclusion One stage anterior debridement combined with posterior pedicle screw fixation is a safe and effective method for the treatment of cervical vertebra instability and nerve function injury caused by cervical intervertebral space infection.It provides a new way for the treatment of cervical intervertebral space infection.

Objective:To prepare pH-sensitive liposomes to avoid the degradation of monophosphoryl lipid A (MPLA) by lysosomes.Methods:Using DOPE and CHEMS as carrier materials, pH-sensitive liposomes were prepared by thin-film dispersion method. Particle sizes and Zeta potential of the liposomes were detected by dynamic light scattering. The morphological features of pH-sensitive liposomes under different pH conditions were observed by transmission electron microscopy. Flow cytometry was performed to detect the phagocytosis of liposomes by THP-1 and DC2.4 cells. Confocal laser microscopy was used to observed the colocalization of liposomes and lysosomes. BALB/c mice were immunized with hepatitis B surface antigen (HBsAg) using MPLA pH-sensitive liposome as an adjuvant. The levels of serum anti-HBs were quantitatively detected by ELISA. IFN-γ and IL-2 spot forming cells (SFCs) in mouse splenic lymphocytes were detected by ELISPOT.Results:The pH-sensitive liposomes were constructed with an average particle size of (90.90±1.13) nm, polydispersity index (PDI) of 0.076±0.013 and Zeta potential of (-27.900±0.666) mV. As the pH value of the solution decreased, the particle size increased significantly and the liposomes presented irregular shapes, indicating the pH-sensitive features. The phagocytosis rates by THP-1 cells and DC2.4 cells were 10.40% and 12.40% for pH-sensitive fluorescent liposomes, and 1.09% and 0.28% for fluorescent liposomes. Confocal laser microscopy revealed that pH-sensitive fluorescent liposomes were phagocytosed by THP-1 cells and existed in the cytoplasm, while fluorescent liposomes existed in lysosomes. Compared with MPLA liposomes, MPLA pH-sensitive liposomes could significantly improve the cellular immune response in mice. The levels of IFN-γ and IL-2 SFCs in the MPLA pH-sensitive liposome group were significantly higher than those in the MPLA liposome group ( P<0.01) and the non-adjuvant group ( P<0.001). Conclusions:The pH-sensitive liposome delivery system could improve the utilization of MPLA as an adjuvant.

Objective:To investigate the effect of radiofrequency radiation (RF) from 5G mobile phone communication frequency bands (3.5 GHz and 4.9 GHz) on the permeability of the blood-brain barrier (BBB) in mice.Methods:A total of 24 healthy adult male C57BL/6 mice (6-8 weeks old) were randomly divided into Sham, 3.5 GHz RF and 4.9 GHz RF groups, and 8 mice in each group. Mice in the RF groups were systemically exposed to 5G cell phone radiation for consecutive 35 d(1 h/d) with 50 W/m 2 power density. The BBB permeability of mice was detected by Evans Blue (EB) fluorescence experiment. The expression levels of the BBB tight junction-related proteins (ZO-1, occludin and claudin-11) and the gap junction-related protein Connexin 43 were determined by Western blot. Results:The number of spots, fluorescence intensity and comprehensive score of EB were significantly increased in 3.5 GHz RF group and 4.9 GHz RF group compared with the Sham group ( t=12.98, 17.82, P<0.001). Compared with the Sham group, the content of S100B in mouse serum was significantly increased in 3.5 GHz RF group and 4.9 GHz RF group ( t=19.34, 14.68, P<0.001). The BBB permeability was increased in the RF group. The expression level of occludin protein was significantly reduced in the 3.5 GHz RF group ( t=-3.13, P<0.05), and this decrease was much profound in the 4.9 GHz RF group ( t=-6.55, P<0.01). But the protein levels of ZO-1, Claudin-11 and Connexin 43 in the cerebral cortex of the RF groups had no significantly difference in comparison with the Sham group( P>0.05). Conclusions:The continuous exposure of mobile phone RF at 3.5 GHz or 4.9 GHz for 35 d (1 h/d) induces an increase of BBB permeability in the mouse cerebral cortex, perhaps by reducing the expression of occludin protein.

Objective:Based on experience of robotic gastrointestinal surgery at the Department of General Surgery, Clinical Medicine Center of Gansu Provincial Hospital, this study explored the principles and methods of trocar layout for robotic "3+2" mode gastrointestinal surgery, suitable for beginners.Methods:From Apr 2017 to Oct 2022, the robotic gastrointestinal surgery team of Gansu Provincial Hospital completed 998 cases of robotic "3+2" mode gastrointestinal surgery, including 600 cases of gastric cancer, 100 cases of rectal cancer, 98 cases of descending colon and sigmoid colon cancer, 20 cases of transverse colon cancer, and 180 cases of right colon cancer. Through the continuous optimization and improvement of the problems encountered during the operation, combined with the operator's experience, and taking into account various aspects, we developed the robotic "3+2" mode trocar layout for gastrointestinal surgery.Results:Four principles of trocar layout were developed, namely, the principle of lens placement around the navel, the principle of symmetry in the main operation, the principle of 8-10cm distance between trocar holes, and the principle of symmetry in the auxiliary hole lens. Three trocar layout methods and principles applicable to robotic gastric surgery, and four applicable to robotic colorectal surgery were developed.Conclusion:The trocar layout method of robotic "3+2" mode gastrointestinal surgery is established based on a large number of robotic gastrointestinal surgery experiences. This method is simple and easy to learn, with strong repeatability and operability.

Objective:To investigate the effect of thoracic X-ray irradiation on the spermatogenesis of adult male mice.Methods:A total of 24 healthy adult male C57BL/6 mice (6-8 weeks old) were randomly divided into radiation group (Radiation) and sham-radiation group (Sham), 12 mice in each group. The area of thoracic irradiation was 1.5 cm× 2 cm, and the dose rate was 3.04 Gy/min, 8 Gy/d for 3 consecutive days, 24 Gy in total. At 7 d and 21 d after thoracic irradiation, the bilateral testes and epididymal tails were stripped and the testicular index was calculated. The morphology of testis was examined by haematoxylin-eosin (HE) staining, then the diameter of seminiferous tubules and the thickness of seminiferous epithelium were measured. The sperms were collected from the bilateral epididymal tails for sperm counting. The level of apoptosis in testis and levels of apoptosis-related proteins were detected by TUNEL and Western blot, respectively.Results:Compared with Sham group, the morphology of testis and epididymis was seriously damaged, the diameter of seminiferous tubules significantly decreased at 21 d after irradiation ( t = 8.93, P < 0.05), and the seminiferous epithelium significantly decreased at 7 d and 21 d after irradiation ( t = 4.24, 12.77, P < 0.05). In addition, the number of sperms significantly decreased ( t = 4.30, 2.98, P < 0.05). The number of TUNEL positive cells in the seminiferous epithelium significantly increased at 7 d and 21 d after irradiation ( t = -2.73, -3.74, P < 0.05). Meanwhile, the level of cleaved Caspase-3 protein significantly increased at 7 d and 21 d after irradiation ( t = -2.96, -2.46, P < 0.05). The concentrations of SCF and GDNF did not change at 7 d after irradiation, but were significantly increased at 21 d after irradiation ( t = -10.46, -5.42, P < 0.05). Conclusions:The thoracic X-ray irradiation could lead to spermatogenesis disorder in male adult mice, and the induction of spermatogenic cell apoptosis and the secretory dysfunction of sertoli cells may be involved.