Effects of recombinant human growth hormone (r-hGH) on experimental osteoporotic fracture healing

ＴＤｅｐａｒｔｍｅｎｔｏｆＯｒｔｈｏｐａｅｄｉｃｓ ,ＮｉｎｔｈＰｅｏｐｌｅ ｓＨｏｓｐｉｔａｌ,ＳｈａｎｇｈａｉＳｅｃｏｎｄＭｅｄｉｃａｌＵｎｉｖｅｒｓｉｔｙ ,Ｓｈａｎｇｈａｉ 2 0 0 0 11,Ｃｈｉｎａ(ＨａｏＹＱ ,ＤａｉＫＲ ,ＧｕｏＬＨ ,ＷａｎｇＹＪａｎｄＴａｎｇＴＴ)ｈｅｍａｊｏｒｈａｒｍｔｏｏｓｔｅｏｐｏｒｏｓｉｓｉｓｆｒａｃｔｕｒｅ .Ｂｕｔｌｉｔｔｌｅｈａｓｂｅｅｎｋｎｏｗｎａｂｏｕｔｔｈｅｍｅｃｈａｎｉｓｍｏｆｏｓｔｅｏｐｏｒｏｔｉｃｆｒａｃｔｕｒｅｈｅａｌｉｎｇｓｏｔｈａｔｃｕｒａｔｉｖｅｅ…     

Comparative Assessment of Physical and Chemical Cyanobacteria Cell Lysis Methods for Total Microcystin-LR Analysis

Standardization and validation of alternative cell lysis methods used for quantifying total cyanotoxins is needed to improve laboratory response time goals for total cyanotoxin analysis. In this study, five cell lysis methods (i.e., probe sonication, microwave, freeze-thaw, chemical lysis with Abraxis QuikLyse^TM, and chemical lysis with copper sulfate) were assessed using laboratory-cultured Microcystis aeruginosa (M. aeruginosa) cells. Methods were evaluated for destruction of cells (as determined by optical density of the sample) and recovery of total microcystin-LR (MC-LR) using three M. aeruginosa cell densities (i.e., 1 × 10⁵ cells/mL (low-density), 1 × 10⁶ cells/mL (medium-density), and 1 × 10⁷ cells/mL (high-density)). Of the physical lysis methods, both freeze-thaw (1 to 5 cycles) and pulsed probe sonication (2 to 10 min) resulted in >80% destruction of cells and consistent (>80%) release and recovery of intracellular MC-LR. Microwave (3 to 5 min) did not demonstrate the same decrease in optical density (<50%), although it provided effective release and recovery of >80% intracellular MC-LR. Abraxis QuikLyse^TM was similarly effective for intracellular MC-LR recovery across the different M. aeruginosa cell densities. Copper sulfate (up to 500 mg/L Cu²⁺) did not lyse cells nor release intracellular MC-LR within 20 min. None of the methods appeared to cause degradation of MC-LR. Probe sonication, microwave, and Abraxis QuikLyse^TM served as rapid lysis methods (within minutes) with varying associated costs, while freeze-thaw provided a viable, low-cost alternative if time permits.     

Myc drives apoptosis in PC12 cells in the absence of Max.

A conditionally active chimeric form of the c-Myc protein fused to the ligand-binding domain of the estrogen receptor (MycER) was expressed in PC12 cells. Induction of Myc activity resulted in a threefold increase in apoptosis after 5 days when cells were maintained in 1% serum. The effect of Myc overexpression was dependent on its DNA-binding domain but not on its heterodimeric binding protein Max, which is absent in PC12 cells. Preincubation of the c-Myc overexpressing cells with either NGF or bFGF, but not EGF, prevented the Myc-mediated increase in apoptosis, although the signaling pathways used by NGF and bFGF to block cell death differed. NGF-mediated rescue was mediated by the phosphatidylinositol 3'-OH (P13) kinase/Akt pathway while rescue by bFGF was not affected by P13 kinase inhibitors. These results show that Myc can induce apoptosis in PC12 cells in a Max-independent manner and that alternate signaling pathways exist to mediate cell survival.     

体外成牙环境对牙髓干细胞和外胚间充质干细胞分化的影响

目的利用牙胚细胞（TGC）作为诱导成牙环境,将牙髓干细胞（DPSC）、外胚间充质干细胞（EMSC）分别与其共培养,观察DPSC和EMSC的分化能力。方法利用出生后4 d的大鼠TGC作为诱导成牙环境,将培养的DPSC、EMSC使用BrdU标记及鉴定后与其共培养,免疫荧光双标检测标记细胞表面抗原牙本质涎蛋白（DSP）的表达和碱性磷酸酶（ALP）活性的变化,免疫组化染色鉴定及图像分析DPSC、EMSC在成牙环境中的分化能力。结果共培养7 d后,EMSC共培养组DSP阳性细胞的转化率高于DPSC共培养组（P<0.05）。免疫组化染色图像分析结果表明共培养7 d后,共培养组与TGC单独培养组差异显著（P<0.05）。共培养组3、7 d后ALP活性明显增高,EMSC共培养组较DPSC共培养组ALP活性高。结论混合培养的TGC作为诱导细胞分化的微环境与DPSC、EMSC共培养后,能够诱导细胞向成牙本质细胞分化,EMSC分化能力高于DPSC。     

环氧合酶-2和磷酸化P38丝裂原活化蛋白激酶在扁平苔藓皮损中的表达

目的：检测环氧合酶-2（COX-2）及其上游调控蛋白磷酸化P38丝裂原活化蛋白激酶（p-P38MAPK）在扁平苔藓皮损中的表达，探讨其在发病中的意义。方法：采用免疫组化技术检测20例扁平苔藓皮损标本中COX-2和p-P38MAPK的表达情况，20例正常皮肤组织作为对照。结果：20例扁平苔藓皮损标本中COX-2和p-P38MAPK的积分光密度值（IOD）分别为（8.46±1.79）×10³和（11.54±2.85）×103，均明显高于对照组(3.14±2.35)×103和(6.26±3.12)×10³，差别具有统计学意义（均P＜0.01），同时COX-2与p-P38MAPK的表达强度呈正相关（r=0.62，P＜0.01）。结论：扁平苔藓皮损中COX-2表达上调，可能与上游P38MAPK的活化有关，可能是引起扁平苔藓发病的环节之一。     

The Combined Effects of Magnesium Oxide and Inulin on Intestinal Microbiota and Cecal Short-Chain Fatty Acids

Constipation is a common condition that occurs in many people worldwide. While magnesium oxide (MgO) is often used as the first-line drug for chronic constipation in Japan, dietary fiber intake is also recommended. Dietary fiber is fermented by microbiota to produce short-chain fatty acids (SCFAs). SCFAs are involved in regulating systemic physiological functions and circadian rhythm. We examined the effect of combining MgO and the water-soluble dietary fiber, inulin, on cecal SCFA concentration and microbiota in mice. We also examined the MgO administration timing effect on cecal SCFAs. The cecal SCFA concentrations were measured by gas chromatography, and the microbiota was determined using next-generation sequencing. Inulin intake decreased cecal pH and increased cecal SCFA concentrations while combining MgO increased the cecal pH lowered by inulin and decreased the cecal SCFA concentrations elevated by inulin. When inulin and MgO were combined, significant changes in the microbiota composition were observed compared with inulin alone. The MgO effect on the cecal acetic acid concentration was less when administered at ZT12 than at ZT0. In conclusion, this study suggests that MgO affects cecal SCFA and microbiota during inulin feeding, and the effect on acetic acid concentration is time-dependent.     

拇指外展牵引固定器治疗第1掌骨基底部骨折临床观察及生物力学研究

为观察拇指外展牵引固定器的临床效果及生物力学性能。自行研制拇指外展牵引固定器 ,在固定第 1掌骨的同时 ,行拇指近节皮肤牵引。以石膏托外固定及克氏针交叉固定为对照 ,进行生物力学比较研究。结果治疗 18例 ,治愈 13例 ,好转 5例。该方法能为骨折固定提供良好的力学保证 ,固定器的强度裕度为 42 ,其应变、强度和刚度与交叉克氏针内固定和石膏托固定分别相差 3.7%和 6 .2 4%;1%和 2 %;6 .3%和 6 .8%;显示与克氏针内固定无显著性差异 (P >0 .0 0 1) ,但优于石膏固定。认为该方法能满足治疗第 1掌骨基底部骨折的各项生物力学性能 ,安全可靠 ,是一种有效的非手术疗法。     

关节软骨的生物力学特性研究

采用人和兔膝关节软骨标本进行单向拉伸试验和粘弹性试验。结果;人膝关节软骨拉伸强度为4．75tana;人、兔膝关节软骨的粘弹性响应随时间的增加而降低。结论：软骨的结构完整性直接影响其力学性能,应力集中可造成软骨损伤。