Study on Hot Deformation Behavior of an Antibacterial 50Cr15MoVCu Tool Steel

Hot deformation behaviors of an antibacterial 50Cr15MoVCu tool steel were studied. The flow stress curves presented three typical characteristics: (i) a single peak dynamic recrystallization curve, (ii) a monotone incremental work-hardening curve, and (iii) the equilibrium dynamic recovery curve. The flow stress increased with the increase of the deformation rate at each deformation temperature and decreased with the increase of the deformation temperature at the same deformation rate. The thermal activation energy and material constants were Q of 461.6574 kJ/mol, A of 3.42 × 10¹⁷, and α of 0.00681 MPa⁻¹, respectively. The high temperature constitutive equation was: Z=ε˙expQ/RT=3.42×1017sinh0.0068×σ5.6807. Based on the processing maps and microstructure evolution, the best hot working process was a deformation temperature of 1050 °C and deformation rate of 0.001 s⁻¹.     

Deacetylation of 4-(5-acetylamino-2-furyl)thiazole and formation of 1-(4-thiazolyl)-3-cyano-1-propanone by rat liver tissues

The reductive metabolism of the rat carcinogen 4-(5-nitro-2furyl)thiazole (NFT) to 1-4-thiazolyl)-3-cyano-1-propanone (TCP) is reported. Formation of TCP from NFT involved furan ring fission. This could have occurred through involvement of either aminofuran or N-hydroxylaminofuran as precursors. To examine if 4-(5-amino-2-furyl)thiazole is a precursor for TCP, a stable model compound, 4-(5-acetylamino-2-furyl)thiazole (AAFT), was prepared and subjected to enzymatic deacetylation, using rat liver tissue homogenates. AAFT was synthesized by catalytic hydrogenation of NFT with 5% palladium on activated carbon, followed by acetylation with acetic anhydride. AAFT, a white crystalline powder, melted at 168–170°, had an extinction coefficient of 17.9 mM^?1 cm^?1 at 293 nm in ethyl acetate, and exhibited spectroscopic and mass spectral characteristics consistent with the assigned structure. Incubation with rat liver 10,000 g supernatant preparations resulted in the biotransformation of AAFT as evidenced by a decrease in absorption at 290 nm. Incubation of ¹⁴C-labeled AAFT followed by extraction with chloroform-diethyl ether (1:1) resulted in the recovery of a major portion (56%) of the radioactivity in the organic phase when the label was at the 2-position of the thiazole ring, while the major amount (82%) of radioactivity was recovered in the aqueous phase when the 1-¹⁴C-acetyl group was labeled. The radioactivity from the aqueous phase was extractable into the organic phase following acidification to pH 1, an observation consistent with deacetylation. Furthermore, the deacetylation product exhibited a mass spectrum, and retention times in gas and high pressure liquid chromatography, similar to those of synthetic TCP. These data establish 4-(5-amino-2-furyl)thiazole, derived from AAFT by deacetylation, as a precursor for TCP.     

麝香酮对氰化钠加缺糖致PC12细胞缺血损伤的保护作用

目的:研究麝香酮对PC12细胞缺血损伤的影响。方法:在离体培养的PC12细胞,用NaCN加缺糖造成拟缺血损伤模型,通过细胞形态学观察、MTT微量比色、培养介质LDH活力测定,研究了麝香酮对该模型的保护作用。结果:10-7~510-5mol/L范围内,麝香酮呈浓度依赖性地降低NaCN加缺糖造成拟缺血损伤模型培养介质内LDH的释放,其IC50为:43.33μmol/L。在10-7~510-5mol/L范围内,麝香酮呈浓度依赖性地增加NaCN加缺糖造成拟缺血损伤模型培养介质的MTT比色值,其IC50为30.62μmol/L。结论:麝香酮对PC12细胞缺血损伤具有保护作用。     

IRE1α缺陷通过上调内质网钙稳态蛋白降低软骨细胞的自噬功能

目的探究肌醇依赖性激酶1α（IRE1α）通过调控内质网钙稳态蛋白（CHERP）影响软骨细胞自噬功能的相关机制。方法衣霉素（TM）处理人软骨细胞C28/I2，Western blot检测不同时间点的内质网应激和自噬相关蛋白指标。4μ8c、雷帕霉素（Rapa）处理C28/I2（分为：NC组、4μ8c组、Rapa组、4μ8c+Rapa组），Western blot检测自噬相关蛋白指标。分别从软骨组织特异性ERN1基因敲除小鼠（ERN1 CKO）和对照小鼠（Control）软骨组织分离原代软骨细胞，qPCR检测ERN1及自噬相关蛋白ATG5、ATG7的mRNA水平，Western blot检测IRE1α/p-IRE1α、CHERP表达水平，流式细胞术检测胞内钙离子含量。巴佛洛霉素A1（Bafilomycin A1）处理原代软骨细胞（分为Control组、Control+Bafilomycin A1组、ERN1 CKO组、ERN1 CKO+Bafilomycin A1组），Western blot检测LC3Ⅱ、LC3Ⅰ的表达。自噬双荧光病毒在Rapa处理下检测自噬流（分为Control+Rapa组、ERN1 CKO+ Rapa组）。C28/I2中过表达CHERP与IRE1α，免疫荧光检测自噬水平。结果TM处理C28/I2细胞后，内质网应激相关标志蛋白表达上调，LC3Ⅱ/LC3Ⅰ比值上调（P＜0.05），p62表达下调（P＜0.05）。相较对照组，Rapa上调LC3Ⅱ/LC3Ⅰ比值（P＜0.001），4μ8c+ Rapa组相较Rapa组的LC3Ⅱ/LC3Ⅰ比值降低（P＜0.05）。相较于对照组，原代软骨细胞中敲除ERN1/IRE1α后，ERN1（P＜0.01）、ATG5（P＜0.001）、ATG7（P＜0.001）mRNA水平显著下调。IRE1α/p-IRE1α蛋白表达缺失或显著下调（P＜0.01），CHERP蛋白表达上调（P＜0.05），胞内钙离子含量显著上升（P＜0.001）。巴佛洛霉素A1处理原代软骨细胞后，Control+Bafilomycin A1组较Control组的LC3Ⅱ/LC3Ⅰ比值上调（P＜0.01），ERN1 CKO+Bafilomycin A1组较ERN1 CKO组的LC3Ⅱ/LC3Ⅰ比值上调（P＜0.05）、较Control+Bafilomycin A1组的LC3Ⅱ/LC3Ⅰ比值下降（P＜0.05）。自噬双荧光病毒处理后，ERN1 CKO+Rapa组较Control+Rapa组未淬灭LC3-GFP荧光增强（P＜0.05）。C28/I2细胞中过表达CHERP降低LC3荧光强度，过表达IRE1α增强LC3荧光表达并能部分挽救CHERP导致的荧光降低情况。结论IRE1α缺陷通过上调内质网钙稳态蛋白，升高胞内钙离子含量，进一步导致软骨细胞的自噬功能受损。     

Chronic Δ9-Tetrahydrocannabinol in rats: Effect on social interactions,mouse killing,motor activity,consummatory behavior,and body temperature

Behavioral and physiologic effects of daily administration of ⁹-tetrahydrocannabinol (THC) were assessed over a 60-day period, investigating different dose levels (10, 20, 50 mg/kg), routes of administration (i.p., p.o.), drug vehicles [5%–18% propylene glycol(PG)/1% Tween 80-saline; sesame oil], and rat strains (Sprague-Dawley, Wistar, Long-Evans, Fischer). All THC-treated rats showed compulsive motor routines (i.e., forepaw treading, rhythmic jaw movements, prolonged head grooming, and biting of cage wires) after 3–4 weeks. Whether maintained on a restricted feeding regimen or not, three was no evidence for increased aggressive behavior between cagemates in any of the treatment groups. Mouse killing was induced in 70%–75% of all Sprague-Dawley (i.p., PG/Tween 80-saline vehicle) and Fischer rats (p.o., sesame oil vehicle), but not in the other THC-treated groups. Rearing activity was greatly decreased in all THC-treated groups throughout the treatment period. Food and water intake decreased by approximately 40% during the first 2–6 days of THC administration. Growth rate was reduced for the entire treatment period in THC-treated rats. THC decreased rectal temperature on the 1st day, and also on the 2nd day in Fischer rats receiving the drug in sesame oil, but not thereafter. This pattern of effects shows that tolerance develops rapidly to THC's effects on body temperature and consummatory behavior, but not to changes of certain motor activities.     

国内CD44v6与喉鳞癌关系研究的Meta分析

目的对CD44v6与喉鳞癌相关性研究的国内文献进行Meta分析,探讨其病理与临床意义。方法检索中国学术期刊全文数据库、维普及万方数据库,收集1996～2006年国内期刊公开发表的有关喉鳞癌CD44v6表达及其意义的独立病例对照研究论文,在对文献进行异质性检验后,以病例组及对照组比值比（OR值）为效应指标,应用Meta分析软件RevMan4．2．9对各研究报告原始数据进行统计处理,计算合并OR值、95％可信区间及Meta分析森林图。结果最终进入系统评价的文献共有7篇,观察癌患者496例,对照病例99例。Meta分析结果,合并区OR为19．43,95％可信间（CI）为[4．14,91．27],CD44v6表达与喉鳞癌临床分期（p〈0．0001）、分化程度（p=0．0004）、淋巴结转移（P〈0．00001）及5年生存率（P=0．002）均存在明显相关性,而与病变分型（P=0．23）及TNM分期（P=0．12）、患者年龄（P=0．53）及性别（P=0．63）无明显关联。结论相关研究文献的Meta分析显示,CD44v6高表达可能在喉鳞癌的发生、发展、转移及预后中起重要作用。     

增生性玻璃体视网膜病变视网膜前膜CD44v6的表达

目的：观察增生性玻璃体视网膜病变视网膜前膜中CD44v6的表达情况。方法：用免疫组化方法对13例PVR患行玻璃体切割术的剥离的视网膜前膜进行观察。结果：CD44v6阳性表达10例，表达率77％。结论：提示CD44v6在PVR的形成和发展中有一定的作用。     

肿瘤转移相关基因的研究进展

肿瘤的分化、侵袭和转移等一系列病理过程受多种基因的调控,它们在肿瘤细胞浸润和转移机制中或被激活,或被抑制,相互协同或拮抗,最终影响肿瘤细胞的生物学特性。nm23基因抑制肿瘤转移,而CD44v、S100A4基因和TIAM1基因促进肿瘤的扩散。     

低温等离子体促进人牙龈上皮细胞在钛表面的黏附

目的研究低温等离子体（NTAP）处理人牙龈上皮细胞（HGECs）后的生物学行为。方法将HGECs传代培养，待生长活性最佳的第3~5代细胞，消化重悬后经NTAP处理适当时间（0，10，20， 30，60 s）后，接种在钛盘表面，加入口腔角质细胞培养基（OKM），1%双抗、5%CO₂和37 °C孵箱条件下培养不同时间（4，12，24，48 h）贴壁生长，每组中各培养时间设置5个复孔。使用细胞计数试剂盒-8（CCK-8）评估各组黏附细胞的数量；扫描电子显微镜（SEM）观察各组细胞在钛片表面的形态；实时荧光定量聚合酶链式反应（qRT-PCR）检测各组细胞层粘连蛋白α3（Laminin α3）、整合素蛋白β4（Integrin β4）和网蛋白（Plectin）黏附相关基因的表达情况以及Western blot观察各组细胞黏附相关蛋白表达的变化情况。结果在0~20 s内，随着NTAP作用时间的增加，细胞的黏附数量增加；但在20~60 s内，随着作用时间的增加，细胞的黏附数量逐渐减少：证明NTAP处理时间为20 s时最有利于HGECs在钛表面的黏附。CCK-8显示：在设定的培养时间下（20 s），随着培养时间延长，对照组和NTAP组细胞在钛表面的黏附数量增加。与对照组相比，在各培养时间点NTAP组细胞在钛表面的黏附数量更多（P<0.05）。SEM显示：NTAP组细胞在钛表面更明显地表现出不规则的多边形、突起与伪足较多及更大的细胞扩散面积。qRT-PCR显示：NTAP组细胞在钛表面的Lamininα3、Integrin β4和 Plectin黏附相关基因表达都高于对照组（P<0.05）。Western blot也证实：NTAP组细胞在钛表面上Laminin α3、Integrin β4和Plectin黏附相关蛋白的表达均高于对照组。结论HGECs受NTAP处理后，结果表明20 s的作用时间能最大程度增加细胞在钛表面的黏附数量和改变黏附形态，同时能够显著上调Laminin α3、Integrin β4和Plectin黏附相关基因和蛋白的表达，进而能促进HGECs对钛表面的生物封闭作用。