电动磨痂治疗深Ⅱ度烧伤创面的疗效观察

目的：分析比较削痂和电动磨痂在治疗深Ⅱ度烧伤创面的应用。方法：93例深Ⅱ度烧伤住院患者随机分成两组，一组进行削痂手术，另一组行磨痂手术，观察比较两组患者手术治疗效果。结果：与削痂组创面比较，磨痂组创面愈合时间提前5～6d，且愈合质量好，瘢痕增生轻。从病理上看，磨痂手术能最大限度地保留有活力的组织和皮肤附件。结论：用电动磨痂仪施行的磨痂手术操作简单，易于掌握；对组织损伤小，能充分地保留有活力的真皮组织及皮肤附件；创面再上皮化迅速，缩短愈合时间，减轻病人的负担；创面愈合质量好，瘢痕形成轻或无瘢痕。     

3.0T MRI扩散加权成像及灌注加权成像在肾脏良恶性肿瘤鉴别诊断中的效果评价

目的:分析3.0T MRI扩散加权成像(DWI)及灌注加权成像(PWI)在肾脏良恶性肿瘤鉴别诊断中的价值。方法:选可疑肾脏疾病来某院就诊的病患50例,经病理检查2例正常,48例肾脏存在肿瘤,经3.0T MRI检查,比较DWI与PWI检查后指标的差异,PWI检查指标用细胞外血管外间隙容积(Ve)、血液回流常数Kep、血管通透性常数Ktrans表示。DWI检查指标用ADC表示。结果:肾脏恶性肿瘤细胞的Ve、Ktrans的值都比良性肿瘤肾血管平滑肌瘤高,差异存在统计学意义(P<0.05)。ROC曲线下Ktrans、Ve、ADC都有临界值作为鉴别肿瘤良恶性的指标。结论:DWI与PWI可以从不同的方面对肾脏存在的肿瘤的良恶性进行鉴别判定。     

齐拉西酮与奥氮平治疗早期精神分裂症的效果及安全性比较

目的 探讨齐拉西酮与奥氮平治疗早期精神分裂症的效果及安全性.方法 将本院收治100例早期精神分裂症患者随机分为对照组与实验组,各50例.对照组给予奥氮平治疗,试验组给予齐拉西酮治疗.比较两组临床疗效、自我管理能力等差异.结果 试验组总有效率为92.0％,高于对照组的88.0％,差异无统计学意义(P＞0.05).治疗后,试验组自我管理能力为(73.68±5.31)分,高于对照组的(60.66±4.37)分;试验组不良反应率为4.0％,低于对照组的20.0％;差异均具有统计学意义(均P＜0.05).结论 齐拉西酮较奥氮平治疗早期精神分裂症效果佳,值得临床选择.     

Update on the disease burden and circulating strains of rotavirus in China: A systematic review and meta-analysis

Background

Rotavirus is the most common cause of severe diarrhea in children, and most associated deaths occur in developing countries. Two new internationally licensed vaccines are expected to be launched in the near future in China. We performed a systematic review and meta-analysis of rotavirus studies to update information on the burden of rotavirus disease in China.

Materials and methods

Eligible studies published before 2011 were identified using PubMed/Medline, Embase, Cochrane Library, LILACS, WHOLIS, and two Chinese literature databases, CNKI, and WANFANG. Arc-sine transformations and the DerSimonian–Laird random-effects or fixed-effects models were used for meta-analysis.

Results

A total of 211 studies were included in this review, of which 63 (29.9%) were inpatient studies, 26 (12.3%) were outpatient, 122 (57.8%) were combined. Community subjects were investigated in two combined studies. Rates of gastroenteritis caused by rotavirus in inpatients, outpatients, and community children were 42.6%, 32.5% and 9.3%, respectively. The most common G type was G3 (39.3%), followed by G1 (30.3%), G2 (7.2%), and G9 (3.3%). The most common P types were P[8] (50.2%), P[4] (18.2%), and P[6] (7.2%). The most prevalent G-P combinations were G3P[8] (32.1%), G1P[8] (23.0%), and G2P[4] (7.9%).

Conclusion

Rotavirus is an important cause of both severe and mild diarrheal disease in children <5 years of age in China; G3P[8] is the most prevalent strain. The introduction of an effective rotavirus vaccine to Chinese pediatric immunization programs is necessary.     

多层CT门静脉造影在肝脏肿瘤中的临床应用

目的探讨门静脉多层CT成像在临床中的应用价值.方法收集资料完整的病例57例,其中肝硬化患者12例,原发肝脏肿瘤18例,转移性肝脏肿瘤21例,肝外肿瘤累及门静脉6例.术前行多层CT(MSCT)门静脉造影,行多种方法重建.同时将影像检查与术中结果进行对照,分析MSCTP的诊断价值.结果MSCTP可显示门静脉5～6级分支,门静脉的解剖分型显示清晰.肝硬化门静脉增粗,侧支循环开放情况显示清晰.肝内肿瘤对门静脉分支浸润表现为包绕、穿行、推移.肝外肿瘤对门静脉属支包裹或浸润6例.所得影像结果与外科术中所见具有较高的一致性.结论多层CT门静脉造影具有较高的临床应用价值,对外科进行术前判断,术后评估具有重要的意义.     

3.0T MRI对绝经前女性正常子宫的ADC值研究

目的研究不同年龄段绝经前女性的正常子宫三层结构(肌层、结合带及内膜)在不同月经周期的表观扩散系数(apparent diffusionco efficient,ADC)的变化。资料与方法将67名健康女性分成三组(A组20～29岁,B组30～39岁,C组40～49岁),分别于增殖中期及分泌中期行2次MR检查,研究不同结构区、年龄段及生理周期对子宫ADC值的影响。结果子宫三层结构的ADC值在同一周期同一年龄组两两比较均有明显差异(肌层最高,内膜居中,结合带最低);B组内膜的ADC值在两期均高于A组和C组,而A组和C组内膜的ADC值在两期均无明显差异,其余结构区无明显年龄差异;各个年龄段子宫内膜的ADC值在增殖中期均低于分泌中期,而各年龄段肌层与结合带的ADC值在不同周期间差异不明显。结论不同结构区、年龄及周期会对子宫(尤其内膜)的ADC值产生影响,当利用ADC值精确分析子宫病变时应考虑这些因素,尤其有助于监测疗效及鉴别肿瘤复发。     

正常人听觉皮层BOLD-fMRI的研究

目的 利用血氧水平依赖(blood oxygenation level dependent, BOLD)功能磁共振成像(functional magnetic resonance imaging, fMRI)(BOLD-fMRI)技术观察纯音刺激时正常人大脑两半球听觉皮层激活情况,对激活体积和信号强度进行定量分析,比较其差异.方法 15例健康志愿者行听觉刺激BOLD-fMRI检查.刺激声音为声强90dB、频率l000Hz的正弦波纯音脉冲.采用梯度回波平面成像(gradient echo planar imaging,GRE-EPI),快速采集全脑影像.所有数据均经统计参数图(statistical parametric mapping2,SPM2)软件离线后处理,获得听觉功能的解剖功能图、激活体积和信号强度.结果 15例健康志愿者纯音刺激时颞叶区均出现激活,颞上回激活率最高,其次为颞中回、颞横回.刺激单耳时对侧听觉皮层激活体积和信号强度明显大于同侧(P＜0.01).结论 正常人纯音刺激单耳时一般都有双侧听觉皮层激活,对侧听觉皮层激活体积和信号强度明显大于同侧,表现为对侧半球传导优势.     

Myosin binding protein-C activates thin filaments and inhibits thick filaments in heart muscle cells

Myosin binding protein-C (MyBP-C) is a key regulatory protein in heart muscle, and mutations in the MYBPC3 gene are frequently associated with cardiomyopathy. However, the mechanism of action of MyBP-C remains poorly understood, and both activating and inhibitory effects of MyBP-C on contractility have been reported. To clarify the function of the regulatory N-terminal domains of MyBP-C, we determined their effects on the structure of thick (myosin-containing) and thin (actin-containing) filaments in intact sarcomeres of heart muscle. We used fluorescent probes on troponin C in the thin filaments and on myosin regulatory light chain in the thick filaments to monitor structural changes associated with activation of demembranated trabeculae from rat ventricle by the C1mC2 region of rat MyBP-C. C1mC2 induced larger structural changes in thin filaments than calcium activation, and these were still present when active force was blocked with blebbistatin, showing that C1mC2 directly activates the thin filaments. In contrast, structural changes in thick filaments induced by C1mC2 were smaller than those associated with calcium activation and were abolished or reversed by blebbistatin. Low concentrations of C1mC2 did not affect resting force but increased calcium sensitivity and reduced cooperativity of force and structural changes in both thin and thick filaments. These results show that the N-terminal region of MyBP-C stabilizes the ON state of thin filaments and the OFF state of thick filaments and lead to a novel hypothesis for the physiological role of MyBP-C in the regulation of cardiac contractility.Muscle contraction is driven by the relative sliding of the actin-containing thin filaments along the myosin-containing thick filaments arranged in a parallel array in the muscle sarcomere (Fig. 1A). Filament sliding in turn is driven by a structural change in the myosin head domains (Fig. 1B) while they are bound to actin, coupled to the hydrolysis of ATP (1). Contraction of skeletal and cardiac muscle is triggered by calcium binding to troponin in the thin filaments, accompanied by a change in the structure of the thin filaments that permits myosin head binding (2). However, the strength and dynamics of contraction are modulated by posttranslational modifications in other sarcomeric proteins, including the myosin regulatory light chain (RLC) (3), which is part of the myosin head, and myosin binding protein-C (4–6) (MyBP-C) (Fig. 1B). In an emerging concept of thick filament regulation in striated muscle that is analogous to myosin-linked regulation in smooth muscle (7–11), RLC and MyBP-C are thought to modulate contraction by controlling the conformation of the myosin heads.Open in a separate windowFig. 1.Sarcomere location and domain architecture of MyBP-C. (A) C-zone (green) of the thick filament in relation to its proximal (P) and distal (D) regions and the thin filament (gray). (B) Cartoon representation of MyBP-C (green) anchored to the thick filament backbone (purple) via its C-terminal domains; myosin heads are pink and troponin is yellow. (C) Domain organization and interactions of MyBP-C.According to this concept, the thick filament has an OFF state in which the myosin heads are folded back against its surface (Fig. 1B), rendering them unavailable for interaction with actin, and an ON state in which the heads are released from the thick filament surface and made available for actin binding. The physiological and pathological significance of thick filament regulation and its relationship to the well-studied thin filament mechanisms remain poorly understood, but much recent attention has focused on MyBP-C for two main reasons. First, mutations in the cardiac MYBPC3 gene are commonly associated with hypertrophic cardiomyopathy (12, 13), and this association has driven a wide range of studies at the molecular, cellular, and whole-animal levels aimed at understanding the etiology of MYBPC3-linked disease. Second, although MyBP-C is a constitutive component of the thick filament, there is a large body of evidence that it can also bind the thin filaments (14, 15), raising the possibility that one role of MyBP-C may be to synchronize the regulatory states of the thin and thick filaments (11, 15–17).MyBP-C is localized to the central region or “C-zone” of each half-thick filament (Fig. 1A), appearing in nine transverse stripes with a 43-nm periodicity closely matching that of the myosin heads (Fig. 1B) (10). MyBP-C has 11 Ig-like or fibronectin-like domains (Fig. 1C) denoted C0–C10, with additional linking sequences, notably the MyBP-C “motif” or “m” domain between C1 and C2 and the proline/alanine-rich (P/A) linker between C0 and C1. The m domain has multiple phosphorylation sites (4–6). Constitutive binding to the thick filament is mediated by interactions of domains C8–C10 with myosin and titin. The C1mC2 region binds to the coiled-coil subfragment-2 (S2) domain of myosin adjacent to the myosin heads, and this interaction is abolished by MyBP-C phosphorylation (5); the C0 domain binds to the RLC in the myosin head itself (18). The N-terminal domains of MyBP-C also bind to actin in a phosphorylation-dependent manner (14, 15) (Fig. 1B), and EM and X-ray studies on intact sarcomeres of skeletal muscle suggest that MyBP-C binds to thin filaments under relaxing conditions (10, 11).The function of MyBP-C and the mechanisms underlying its modulation in cardiomyopathy remain poorly understood, however. Ablation of MyBP-C in a knockout mouse model leads to a hypertrophic phenotype associated with impaired contractile function (19), but cardiomyocytes isolated from these mice exhibit increased power output during working contractions (20). A range of studies at the isolated protein and cellular levels have led to the concept that MyBP-C exerts a predominantly inhibitory effect on contractility mediated through two distinct mechanisms (15, 16, 21). MyBP-C may tether myosin heads to the surface of the thick filament, preventing their interaction with actin, and its N terminus may bind to thin filaments, inhibiting interfilament sliding at low load. Other studies, however, have demonstrated an activating effect of MyBP-C mediated by binding of its N-terminal domains to the thin filament. N-terminal fragments of MyBP-C enhance force production in skinned cardiac muscle cells and motility in isolated filament preparations at zero or submaximal calcium concentrations (22–25). The same effect is observed in cardiomyocytes from MyBP-C knockout mice (22), suggesting that the activating effect is not due to competitive removal of an inhibitory effect of native MyBP-C.To resolve these apparently contradictory hypotheses about the physiological function of the N-terminal domains of MyBP-C, we determined the structural changes in the thick and thin filaments of intact sarcomeres in heart muscle cells induced by N-terminal MyBP-C fragments using bifunctional rhodamine probes on RLC and troponin C (TnC) (26). These probes allowed the structural changes in both types of filament to be directly compared with those associated with calcium activation and myosin head binding in the native environment of the cardiac muscle sarcomere. The results lead to a model for the physiological function of MyBP-C that integrates the regulatory roles of the thin and thick filaments and the inhibitory and activating effects of MyBP-C at the level of the intact sarcomere.     

Phylogenetic and recombination analysis of human bocavirus 2

Background  

Human bocavirus 2(HBoV2) and other human bocavirus species (HBoV, HBoV3, and HBoV4) have been discovered recently. But the precise phylogenetic relationships among these viruses are not clear yet.