Pax7 shows higher satellite cell frequencies and concentrations within intrafusal fibers of muscle spindles

Intrafusal fibers within muscle spindles make up a small subpopulation of muscle fibers. These proprioceptive fibers differ from most extrafusal fibers because, even in maturity, their diameters remain small, and they retain expression of developmental myosins. Although both extrafusal and intrafusal fibers contain satellite cells (SCs), comparatively little is known about intrafusal SCs. Analyzing chicken fast-phasic posterior (PLD) and slow-tonic anterior (ALD) latissimus dorsi muscles, we show that SCs of both intrafusal and extrafusal fibers express Pax7. We further test the hypotheses that intrafusal fibers display parameters reflective of extrafusal immaturity. These hypotheses are that intrafusal fibers contain (a) higher SC frequencies (number of SC nuclei/all nuclei within basal lamina) and concentrations (closer together) and (b) smaller myonuclear domains than do adjacent extrafusal fibers. IHC techniques were applied to PLD and ALD muscles excised at 30 and 138 days posthatch. The hypotheses were validated, suggesting that intrafusal fibers have greater capacities for growth, regeneration, and repair than do adjacent extrafusal fibers. During maturation, extrafusal and intrafusal fibers show similar trends of decreasing SC frequencies and concentrations and increases in myonuclear domains. Thus, extrafusal and intrafusal fibers alike should exhibit reduced capacities for growth, regeneration, and repair during maturation.     

拇指背侧皮神经营养血管皮瓣修复对拇指远端软组织缺损的效果观察

目的:探讨拇指背侧皮神经营养血管皮瓣修复拇指远端软组织缺损的临床效果。方法:选取我院2014年1月至2016年12月收治的拇指远端软组织缺损患者100例,随机分为对照组和观察组。对照组采取腹部皮瓣对拇指远端软组织缺损进行修复,观察组采取拇指背侧皮神经营养血管皮瓣对其进行修复。通过随访患者,记录分析皮瓣的生存状况、感觉指标、外观以及手部功能的DASH评分比较两组的修复效果。结果:观察组50例患者皮瓣全部成活。对照组50例皮瓣全部成活。与对照组相比,观察组在触觉、温度觉、单丝、两点辨别觉、瘢痕挛缩方面明显优于对照组(P0.05),臃肿发生率明显低于对照组(P0.05)。观察组DASH评分为29.56±2.14分,对照组为38.13±3.12分,观察组的DASH评分明显低于对照组(P0.05)。结论:拇指背侧皮神经营养血管皮瓣修复拇指远端软组织缺损手术不破坏主要血管神经,对供区影响小,操作简单,修复的指腹感觉,拇指外形较佳,是较为理想的选择。     

Distribution of polymorphic forms of troponin components in extra- and intrafusal fibers of an avian slow muscle

Summary By indirect immunofluorescence microscopy, the reactivities of extra- and intrafusal muscle fibers with antibodies against troponin (TN) components were studied in an avian slow muscle, the anterior latissimus dorsi (ALD) of the chicken. Serial cross sections of the muscle were exposed to antibodies specific to TN components (TN-T, -I, and -C) from adult chicken breast and ventricular muscles. In extrafusal fibers, four distinct categories were identified on the basis of differential reactivity with these antibodies. The predominant population of fibers (> 95%) reacted weakly only with antiventricular TN-C. The second type of fibers (< 5%) was stained with antibodies raised against breast TN components. The third group of fibers (< 1%) was labeled not only with antibreast TN components, but also with antiventricular TN-T and -C. The last class of fibers (< 1%) reacted with antibodies directed against ventricular TN-T and -C. These results were correlated with myofibrillar ATPase staining patterns of fibers. In intrafusal muscle fibers of this muscle, the same four types of fibers were observed; in these fibers, however, there appeared to be a longitudinal variation in the reactivity. In conclusion, the slow ALD muscle of the adult chicken contains populations of both extrafusal and intrafusal fibers which are heterogeneous in reactivity with TN component antibodies.     

A Judgment on Postmortem Aging in Longissimus Dorsi Based on a Peptide Substrate Library

We attempted to develop a method to determine easily and effectively the degree of postmortem aging of pork longissimus dorsi (LD) by measuring the activity of proteases in the LD using fluorogenic peptide substrates. LD was used to measure the change with time in the protease activity detected with these substrates. Determining the variations within the LD muscles, strong positive correlations were found between changes in hardness and fluorescence intensities against Ac-Ala-MCA, Ac-Met-MCA, Ac-Ser-MCA, Ac-Thr-MCA, and Ac-Ala-Phe-MCA (P<0.005), and strong negative correlations were found between changes in total amounts of free amino acids and Ac-Ala-MCA, Ac-Met-MCA, Ac-Ser-MCA, Ac-Thr-MCA, and Ac-Ala-Phe-MCA (P<0.001). Negative correlations were also observed between changes in the amounts of free Ala, Arg, Lys, Leu, Met, Phe, and Tyr and the fluorescence intensities against Ala, Arg, Lys, Leu, Met, Phe, and Tyr-MCA respectively (P<0.001).     

Properties and sidedness of 5'-nucleotidase in rat red cell ghosts

The occurrence of a Mg++-activated 5'-AMPase activity in rat ghosts is demonstrated. This activity is inhibited by the alpha, beta-methyleneadenosine 5'-diphosphate, a specific inhibitor of 5'-nucleotidase. The enzyme has an apparent Km of approximately 90 microM, and is located on the exterior side of the plasma membrane.     

负压封闭引流技术在腹部带蒂皮瓣供瓣区的应用

目的:探讨负压封闭引流(vaccumsealingdrainage,VSD)技术在腹部带蒂皮瓣供瓣区中的治疗作用。方法:10例上肢深度创面大小为9×6 cm-14×9 cm,创面清创后行腹部带蒂皮瓣移植,皮瓣面积10×7 cm-20×15 cm,供瓣区应用VSD覆盖,医用半透性贴膜封闭整个术区,连接中心负压,持续低负压吸引,每日外用1000 mL生理盐水持续冲洗VSD。约3周后行皮瓣断蒂术,供瓣区植皮。结果:10例皮瓣全部存活,1例患者术后当天引流区域出现疼痛,经止痛治疗后未再出现。1例患者术后2周出现VSD堵塞,经处理后恢复正常引流。无VSD装置更换病例。供瓣区周边皮肤无浸渍及感染现象,VSD撤除后见基底肉芽组织生长新鲜,创面均无感染,移植皮片存活。结论:VSD技术可以有效保护供瓣区,刺激肉芽生长,为后期皮片移植闭合创面提供了良好条件。VSD技术可安全有效的应用于腹部带蒂皮瓣供瓣区。     

Crystal Structure of the Human Rad9-Hus1-Rad1 Clamp

Three evolutionarily conserved proteins, Rad9, Hus1, and Rad1, form a heterotrimeric 9-1-1 complex that plays critical roles in cellular responses to DNA damage by activating checkpoints and by recruiting DNA repair enzymes to DNA lesions. We have determined the crystal structure of the human Rad9 (residues 1-272)-Hus1-Rad1 complex at 2.5 Å resolution. The 9^1-272-1-1 complex forms a closed ring, with each subunit having a similar structure. Despite its high level of similarity to proliferating cell nucleus antigen in terms of overall structure, the 9^1-272-1-1 complex exhibits notable differences in local structures, including interdomain connecting loops, H2 and H3 helices, and loops in the vicinity of the helices of each subunit. These local structural variations provide several unique features to the 9-1-1 heterotrimeric complex—including structures of intermolecular interfaces and the inner surface around the central hole, and different electrostatic potentials at and near the interdomain connecting loops of each 9-1-1 subunit—compared to the proliferating cell nucleus antigen trimer. We propose that these structural features allow the 9-1-1 complex to bind to a damaged DNA during checkpoint control and to serve as a platform for base excision repair. We also show that the 9^1-272-1-1 complex, but not the full-length 9-1-1 complex, forms a stable complex with the 5′ recessed DNA, suggesting that the C-terminal tail of Rad9 is involved in the regulation of the 9-1-1 complex in DNA binding.     

乳腺癌保乳术后应用紫杉醇脂质体对背阔肌肌瓣修复的疗效研究

摘要 目的：研究紫杉醇脂质体在乳腺癌保乳术后对背阔肌肌瓣修复的应用价值。方法：选取本院2015年1月~2018年10月收治的65例行保乳术治疗的乳腺癌患者作为研究对象,采用随机数表法将患者分为观察组33例和对照组32例,术后均行背阔肌肌瓣修复手术,对照组予以单纯的表柔比星+环磷酰胺+多西他赛进行术后化疗,观察组予以表柔比星+环磷酰胺+紫杉醇脂质体进行术后化疗。结果：观察组患者达到完全缓解(CR) 14例,部分缓解(PR) 13例,稳定(SD) 5例,进展(PD) 1例,客观缓解率(ORR)为81.82%;对照组患者达到CR 11例,PR 8例,SD 11例,PD 2例,ORR为59.38%,差异有统计学意义（P<0.05）。观察患者的乳房修复美学评价优良率90.91%较对照组的71.88%升高（P<0.05）;观察组满意度为90.91%,对照组满意度为78.13%,两组比较有统计学差异（P<0.05）。两组患者术后并发症发生情况比较无明显差异（P>0.05）。两组化疗相关的腹泻和呕吐等不良反应发生率比较有统计学差异（P<0.05）。结论：乳腺癌保乳术后应用紫杉醇脂质体对背阔肌肌瓣修复的疗效较好,安全性较理想。     

Crystal structures of inhibitor complexes of M‐PMV protease with visible flap loops

Mason‐Pfizer monkey virus protease (PR) was crystallized in complex with two pepstatin‐based inhibitors in P1 space group. In both crystal structures, the extended flap loops that lock the inhibitor/substrate over the active site, are visible in the electron density either completely or with only small gaps, providing the first observation of the conformation of the flap loops in dimeric complex form of this retropepsin. The H‐bond network in the active site (with D26N mutation) differs from that reported for the P2₁ crystal structures and is similar to a rarely occurring system in HIV‐1 PR.