0.05). A rise in CAP threshold and reduction in CM amplitude after perfusion were found in the other three groups(P

Objective:To explore the significance of the clinical target volume (CTV) dose optimization in the upper and middle neck in protecting the laryngopharynx, anterior and posterior rings during intensity-modulated radiotherapy (IMRT) and multimodal imaging system for nasopharyngeal carcinoma.Methods:Clinical data of 298 nasopharyngeal carcinoma patients admitted to Jiangsu Cancer Hospital from 2016 to 2018 were retrospectively analyzed. According to the following five strategies of CTV dose optimization in the upper and middle neck: group A, complete optimization of bilateral cervical lymph nodes (CLNs), that is, the CTV doses of bilateral CLNs were 50.4 Gy; group B, complete optimization of unilateral CLNs, that is, the CTV dose of unilateral CLNs was 50.4 Gy and the contralateral CLNs was 60 Gy; group C, incomplete optimization of bilateral CLNs, that is, the CTV doses of bilateral CLNs were 50.4 Gy, while the suspicious positive CLNs were selectively boosted to 60 Gy; group D, incomplete optimization of unilateral CLNs, that is, the CTV dose of unilateral CLNs was 50.4 Gy and the suspicious positive CLNs were selectively boosted to 60 Gy, and the CTV dose of contralateral side was 60 Gy; group E: no optimization, that is, the CTV doses of bilateral CLNs were 60 Gy.Results:Among 298 patients, 215 patients received dose optimization and 83 cases did not receive dose optimization. In the dose optimization schemes, 114 cases were assigned in group A, 36 cases in group B, 60 cases in group C and 5 cases in group D. The median (range) follow-up time was 28.5(6.0-46.3) months. The overall survival rate was 95.6%, the progression-free survival rate was 84.2% and the locoregional control rate of CLNs was 98.0%. Local relapse of CLNs occurred in six patients, including 1 case of retropharyngeal lymph node, 4 cases of Ⅱ area and 1 case of Ⅳ area. The P values of average dose of laryngopharynx in group A, group B, group C and group D compared with that in group E were<0.001, 0.016, 0.001 and 0.572, respectively. The P values of the average dose of the anterior ring in group A, group B, group C and group D compared with that in group E were<0.001, 0.011, <0.001 and 0.805, respectively. The P values of the average dose of the posterior ring in group A, group B, group C and group D compared with that in group E were<0.001, 0.004, <0.001 and 0.252, respectively.Conclusions:Combined with the metastatic rules of CLNs and multimodal imaging system, it is safe to optimize the CTV dose of the upper and middle neck during IMRT in nasopharyngeal carcinoma patients, which can significantly reduce the doses of laryngopharynx, anterior and posterior rings, thereby providing evidence for reducing the CTV dose in the upper and middle neck.

OBJECTIVETo investigate the prophylactic effect of low calcium concentration perilymph on noise-induced hearing loss.

METHODSForty guinea pigs with normal hearing weighing 250-350 g were assigned to five groups (8 in each group): (1) Ca(2+)-deficient perilymph perfusion (CDP) for 2 h; (2) white noise (120 dB SPL) exposure (WNE) only for 1 h, (3) combination of calcium-deficient perilymph perfusion and white noise (120 dB SPL) exposure (WNE + CDP); (4) normal artificial perilymph (NAP) perfusion for 2 h; and (5) white noise exposure + normal artificial perilymph perfusion (WNE + NAP) for 2 h. Compound action potentials (CAP) evoked by click was recorded from round window every 15 min. The cochleae from 5 animals in each group were examined with scanning electron microscope.

RESULTSThe CAP for group 1 experienced a threshold shift (TS) of 15-26 dB, while group 2 yielded a 46-59 dB TS and group 3 a 37-45 dB TS; no threshold shift occurred in group 4. The CAP TS in group 5 was 33-64 dB. The CAP TS of group 3 was less than that of group 2. After one hour of noise exposure, the CAP TS of group 3 were 45.92 +/- 2.90 dB and 59.30 +/- 3.95 dB in group 2. There were significant differences (P < 0.05) between groups 3 and 2. The CAP TS of group 3 was less than that of group 5 at the points of 1, 1.5 and 2 h after noise exposure. There was a significant difference between groups 3 and 5 (P < 0.01). Stereocilia of 89 OHC(3) were in disarray in five cochleae after noise exposure in group 2. The cuticular plates of 8 OHC(2),3 sank and the stereocilia became fused in only one animal cochlea after noise exposure in group 3 combined with low calcium perilymph perfusion.

CONCLUSIONSLow calcium concentration appears to participate in preventing noise-induced hearing loss and the rising of calcium concentrations in inner hair cells after noise exposure, which may have been due to the opening of calcium channels in inner hair cells during noise exposure. The mechanism of the prophylactic effect might be caused by a lower calcium concentration in inner hair cells in the cochlea attenuating the influence of noise exposure on hearing loss; calcium deficient perilymph perfusion prevented calcium accumulation in inner hair cells of the cochlea. The motility of the OHCs might be partially inhibited by low calcium concentration that reduced noise-induced hearing loss in turn.

Action Potentials ; Animals ; Calcium ; analysis ; physiology ; Cochlea ; pathology ; physiology ; Endolymph ; metabolism ; Guinea Pigs ; Hair Cells, Auditory ; metabolism ; Hearing Loss, Noise-Induced ; prevention & control ; Perilymph ; physiology

Objective To assess the feasibility of adenoviral vectors mediate cochlear gene transfer by postau-ricular microinjection through the round window membrane in mouse. Methods Twelve 5-week old C57BL/6J mice were selected for the study: 8 were implanted with Ad-EGFP by postauricular microinjection through the round window membrane, and 4 with artificial perilymphatic fluid. On postoperative days 5 and 14, the animals were sac-rificed and the surface preparation of cochleae was observed. Results Two animals died after operation. Bright green fluorescence in the cochleae was observed in Ad- EGFP groups. Gene expression on day 14 after operation was higher than that on day 5. However, the control group was free of fluorescence. Oonclusion The postauricular route of the cochlear gene transfer in mice is simple to operate with little side-effect. The technique of transgenic delivery into the inner ear through RWM by mieroinjection is feasible and effective.

OBJECTIVETo study the characteristics of male sterility of Bupleurum chinense and further explore the developmental period and reason of abortion for the male sterile plants.

METHODThe morphological characteristics of B. chinense male sterile and normal plants were investigated and compared. The anther development process and pollen viability of two types of plants were examined by microscopic assay.

RESULT AND CONCLUSIONThe shapes and sizes of anther and filament were different between the male sterile and the normal plants. For the male sterile plant's, the filament size was no more than 1/2 of that of normal plants and the anthers were shriveled, failed to dehisce and pollinate naturally, and the pollen grains in the anthers had no vitality. Other morphological characteristics were similar between two types of plants. The main reason leading to male sterility of B. chinense was the abnormal development of tapetum cells with two circumstances. The one is that the tapetum cells degraded early during the period of microsporocyte phase to tetrad phase and the other is that the tapetum cells proliferated with delayed degradation in the tetrad to uninucleate phase.

Bupleurum ; anatomy & histology ; cytology ; physiology ; Plant Infertility ; Pollen ; anatomy & histology ; cytology ; physiology

OBJECTIVETo investigate the effect of D-AP5 (D-2-amino-5-phosphonopentanoate, a specific NMDA-antagonist) on the increase of intracellular free Ca2+ concentration ([Ca2+]i) induced by glutamate in isolated cochlear inner hair cells (IHCs), and to detect the autoreceptors of the IHC membrane.

METHODSWhen a laser scanning confocal microscope (LSCM) was used, the exogenous glutamate (Glu)-induced changes in [Ca2+]i of isolated IHCs and OHCs of guinea pig cochlea were observed with fluo-3, a fluorescent probe for [Ca2+]i. After D-AP5 or CNQX (6--cyano--7--nitroguinoxaline--2, 3--dione, a specific AMPA- antagonist) was administered, the exogenous glutamate (Glu)-induced changes in [Ca2+]i of isolated IHCs were recorded.

RESULTSIn the presence of a low concentration Glu (3.85 mumol/L), there was an increase of [Ca2+]i in IHCs, whereas there was no change in OHCs. When 50 mumol/L of D-AP5 was administrated in advance, Glu did not induce a corresponding increase in [Ca2+]i in IHCs, and 50 mumol/L of CNQX did not completely block the increase of [Ca2+]i in IHCs.

CONCLUSIONSThese results suggest that the autoreceptors existing in the IHC membrane are mainly of NMDA type, while there are relatively few AMPA receptors. Exogenous Glu is capable of increasing [Ca2+]i in IHCs by acting on the NMDA autoreceptor of IHCs in a positive feedback manner.

2-Amino-5-phosphonovalerate ; pharmacology ; 6-Cyano-7-nitroquinoxaline-2,3-dione ; pharmacology ; Animals ; Calcium ; metabolism ; Excitatory Amino Acid Antagonists ; pharmacology ; Glutamic Acid ; pharmacology ; Guinea Pigs ; Hair Cells, Auditory, Inner ; drug effects ; metabolism ; In Vitro Techniques ; Receptors, N-Methyl-D-Aspartate ; antagonists & inhibitors

Objective To evaluate therapeutic effects of bone marrow mesenchymal stem cells(MSC)derived exosomes on alcohol-induced liver injury.Methods Eighteen male C57BL/6 mice aged 6 to 8 week were randomly divided into control group,model group and exosomes group,with 6 mice in each group.The mice in the model group and the exosomes group were fed with Lieber-DeCarli ad libitum diet(Dyets Inc.)for 4 weeks,followed by gavage a bolus of ethanol at day 26,27 and 28.The mice in the control group matched the alcohol-derived calories with dextran-maltose.Meanwhile,the mice in exosomes group were injected with MSC-exosomes via the tail vein at day 14 and 26.After the experiment,serum levels of alanine aminotransferase(ALT)and aspartate aminotransaminase(AST)were detected,and the pathological changes of liver tissues were observed.The expressions of nuclear factor erythroid 2-related factor 2(Nrf-2),heme oxygenase-1(HO-1),CD63,CD81,TSG101 and Cytochrome C were analyzed by Western blot,and mRNA levels of Nrf-2,HO-1,interleukin(IL)-10 and IL-17 were analyzed by real-time polymerase chain reaction(RT-PCR).The commercial kits were used to detect serum IL-10,IL-17 levels and liver tissue malondialdehyde(MDA),glutathione(GSH),superoxide dismutase(SOD)oxidative stress indicators.The numbers of regulatory T cell(Treg)and help T(Th)17 cells in the liver were analyzed by flow cytometry.One-way analysis of variance was used for comparison between groups.Results MSC-exosomes expressed positive markers CD63,CD81 and TSG101,but did not express the negative markers Cytochrome C.The serum ALT and AST levels in model group were(87.3±25.1)U/L and(223.2±43.5)U/L,respectively,while those in exosomes group were(47.7±12.0)U/L and(128.2±33.6)U/L,respectively.The differences between the two groups were both statistically significant(F=12.818 and 12.226,respectively,both P<0.05).Compared with control group,the SOD activity and GSH level in the model group significantly decreased with statistically significant differences(F=4.245 and 24.074,respectively,both P <0.05).Lieber-DeCarli ethanol feeding significantly increased intrahepatic MDA level in the model mice,which was reversed by MSC-exosomes supplementation,and the difference was statistically significant(F=36.675,P <0.05).Compared with control group,the intrahepatic protein expressions of Nrf-2 and HO-1 in model group were significantly decreased,while the expressions in exosomes group were obviously increased.The differences were statistically significant(F=33.623 and 14.960,respectively,both P <0.05).The expression trends of Nrf-2 and HO-1 mRNA were the same as those of protein expressions(F=20.784 and 276.336,respectively,both P <0.05).The proportions of liver Treg/Th17 in the control group,model group and exosomes group were 4.3±0.9,0.4±0.2,and 3.4±0.5,respectively.The differences among groups were statistically significant(F=64.227,P <0.05).Compared with control group,the serum protein and intrahepatic gene expression of IL-17 in the model group were significantly increased,which were reversed by MSC-exosomes treatment.The differences were statistically significant(F=15.581 and 40.095,respectively,both P<0.05).Serum IL-10 protein levels and intrahepatic IL-10 gene expression were significantly decreased after Lieber-DeCarli ethanol feeding,which were lower than the exosomes group.The differences were statistically significant(F=98.268 and 153.743,respectively,both P <0.05).Conclusions MSC-exosomes transplantation may relieve alcohol-induced liver injury.The mechanism could involve reduction of oxidative stress in the liver via regulating Nrf-2/HO-1 and normalizing the balance of Treg and Th17 cells.

Objective: To compare the effect of insulin-like growth factor-1 receptor (IGF-1R) inhibitor and insulin on renal interstitial macrophage infiltration in mice with type 2 diabetic kidney disease (DKD) mice. Methods: Twenty-four male C57BL/6 mice were selected. After 1 week of adaptive feeding, 6 rats were randomly selected as the control group. The other mice were intraperitoneally injected with streptozotocin (30 mg/kg) after 8 weeks of high-fat and high-sugar feeding. After 72 h, the type 2 diabetes mellitus (DM) models were successfully established if random blood glucose was greater than 16.7 mmol/L. After 8 weeks, if the proteinuria of DM mice increased, the DKD models were successful. DKD mice were divided into 3 groups by random number remainder method: DKD group (n=6), DKD+insulin group (insulin group, n=6, subcutaneous injection of 1-2 U/d insulin) and DKD+IGF-1R inhibitor (IGF-1R inhibitor group, n=6, administered with 30 mg·kg^-1·d^-1 IGF-1R inhibitor). They were continuously treated for 8 weeks. Random blood glucose was tested by glucometer. Blood and urine were collected, and biochemical indicators, such as serum creatinine, urea nitrogen and urine protein were measured by biochemical analyzer. Renal pathological changes were detected by hematoxylin-eosin staining (HE) and periodic acid-schiff staining (PAS). Suppressor of cytokine signaling 2 (SOCS2) mRNA and insulin-like growth factor-1 (IGF-1) mRNA were detected by in situ hybridization. The protein expressions of SOCS2, F4/80, Toll-like receptor 4 (TLR4) and CD68 were detected by immunohistochemistry. Results: Compared with the control group, blood glucose, serum creatinine, serum urea nitrogen and urinary protein excretion rate were significantly higher in DKD mice (all P<0.05), and CD68⁺ cells number, F4/80⁺ cells number and the expression of TLR4 in the tubulointerstitial of DKD mice were significantly higher (all P<0.05). After intervention with insulin or IGF-1R inhibitor, serum creatinine, serum urea nitrogen and urinary protein excretion rate of DKD mice were significantly reduced (all P<0.05). Insulin intervention could significantly reduce blood glucose in mice (P<0.05), but had no significant effect on macrophages. Although IGF-1R inhibitor did not significantly reduce blood glucose, it could significantly reduce the number of CD68, F4/80 positive cells and the expression of TLR4 protein in renal interstitium of DKD mice (all P<0.05). Compared with the DKD group, insulin intervention significantly reduced the expression of IGF-1 protein and mRNA (both P<0.01), and increased the expression of SOCS2 mRNA and protein (both P<0.01). And the expression of SOCS2 protein was correlated with the number of F4/80⁺ cells in insulin group (R²=0.8461, P=0.005). However, IGF-1R inhibitors had no significant effect on SOCS2 expression, but had better inhibition of macrophage infiltration. Conclusion IGF-1R inhibitor has a better inhibitory effect on DKD renal interstitial macrophage infiltration than insulin. The mechanism may be related to the fact that IGF-1R inhibitor does not up-regulate SOCS2 expression, whereas insulin up-regulates SOCS2 expression to activate some potential pathways.

Industrial enzymes have become the core "chip" for bio-manufacturing technology. Design and development of novel and efficient enzymes is the key to the development of industrial biotechnology. The scientific basis for the innovative design of industrial catalysts is an in-depth analysis of the structure-activity relationship between enzymes and substrates, as well as their regulatory mechanisms. With the development of bioinformatics and computational technology, the catalytic mechanism of the enzyme can be solved by various calculation methods. Subsequently, the specific regions of the structure can be rationally reconstructed to improve the catalytic performance, which will further promote the industrial application of the target enzyme. Computational simulation and rational design based on the analysis of the structure-activity relationship have become the crucial technology for the preparation of high-efficiency industrial enzymes. This review provides a brief introduction and discussion on various calculation methods and design strategies as well as future trends.
Biocatalysis ; Biotechnology ; Enzymes ; chemistry ; metabolism ; Metabolic Engineering ; Protein Engineering ; Structure-Activity Relationship

Racemases have been applied for the synthesis of enantiomerically pure compounds through the deracemization methods. Mandelate racemase from Pseudomonas putida was the only enzyme that catalyzes the interconversion of mandelate enantiomers. Using genome mining approaches, we identified 9 mandelate racemases (MRs). A novel racemase named ArMR with higher activity and better soluble protein expression, was isolated from Agrobacterium radiobacter. ArMR displayed the optimum catalytic activity at 50 ℃, pH 7.8 in Tris-HCl buffer. The half-life of ArMR at 50, 40 and 30 ℃ was 0.17, 27.2 and 70.7 h, respectively. KM parameter of ArMR towards (R)- and (S)-mandelic acid was 1.44 and 0.81 mmol/L, respectively; the corresponding kcat value was 410 s⁻¹ and 218 s⁻¹. In addition, KM of ArMR towards (R)- and (S)-2-chloro mandelic acid was 6.48 and 6.37 mmol/L, and the corresponding kcat value 0.22 s⁻¹ and 0.23 s⁻¹, respectively. Meanwhile, Mg²⁺ and Mn²⁺ could activate the enzyme whereas Zn²⁺ inactivated the enzyme completely. Discovery of more novel MRs provides supports further research and development of these racemases.