Skeletal muscle stem cells do not transdifferentiate into cardiomyocytes after cardiac grafting

Skeletal muscle cell-derived grafts in the heart may benefit myocardial performance after infarction. Several studies have suggested that skeletal muscle stem cells (satellite cells) from adult muscle undergo transdifferentiation into cardiomyocytes after grafting into the heart, but expression of cardiac markers in graft cells has not been rigorously confirmed. To determine the fate of satellite cell-derived grafts in the heart, adult rat satellite cells were tagged in vitro with bromodeoxyuridine (BrdU) and grafted into normal hearts of syngeneic rats. At 4 and 12 weeks the graft cells formed multinucleated, cross-striated myofibers that expressed fast skeletal myosin heavy chain (MHC), thus indicating a mature skeletal muscle phenotype. Double staining for the BrdU tag and cardiac-specific markers was employed to identify transdifferentiation. Aside from four questionable cells, none of the 11 grafts examined expressed alpha-MHC, cardiac troponin I, or atrial natriuretic peptide. At 4 weeks, grafts expressed beta -MHC, a hallmark of slow twitch myofibers. By 12 weeks, however, the myofibers had atrophied and downregulated beta-MHC. Grafts never expressed the intercalated disk proteins N-cadherin or connexin43, hence electromechanical coupling did not occur. In conclusion, satellite cells differentiate into mature skeletal muscle and do not express cardiac-specific genes after grafting into the heart. Thus, transdifferentiation into cardiomyocytes did not occur.     

慢性重型肝炎患者血清肝细胞生长因子浓度变化的动态观察

研究慢性病毒性肝炎患者血清中肝细胞生长因子(HGF)的浓度变化与病情的关系,用ELISA法检测19例慢性乙型重型肝炎患者(慢重肝)血清中的HGF浓度的动态变化,并比较生存患者和死亡患者的HGF变化,结果:1.慢重肝患者血清HGF浓度变化与血清TBil的变化相一致,生存患者HGF在达到一个峰值后随血清TBil的降低而降低;死亡患者的HGF则进行性升高,在死亡前达最高值。2.生存患者的HGF峰值浓度为(5.214±1.657)μg/L,TBil为(236±109)μmol/L,PTA为(48.26±10.15)％;而死亡患者分别为(7.521±2.152)μg/L、(412±128).μmol/L、(30.09±14.28)％,均有显著性的差异。HGF在慢重肝患者血清中有较明显的升高,而且与TBil的变化有相关性,动态观察血清HGF的变化可作为判断病情的指标之一。     

Monoclonal and polyclonal immunoglobulin G deposits on tubular basement membranes of native and pretransplant kidneys: A retrospective study

Monoclonal tubular basement membrane immune deposits (TBMID) are associated with progression of interstitial injury in renal allograft. However, the significance of monoclonal and polyclonal TBMID in the native kidney remains unclear. We retrospectively analyzed 1894 native kidney biopsies and 1724 zero-hour biopsies performed between 2008 and 2018 in our institution. The rate of immunoglobulin G (IgG) TBMID was found to be 8.4% among native kidney biopsies and 0.4% among zero-hour biopsies. Polyclonal TBMID is common in IgG4-related tubulointerstitial nephritis (37.5%), diabetic nephropathy (31.3%) and lupus nephritis (25.5%). Monoclonal IgG TBMID was identified in seven cases, including three zero-hour biopsies. The combination of IgG1κ was observed in two cases, IgG1λ in three, and IgG2κ in two. Electron microscopy revealed powdery electron-dense deposits in all cases. Monoclonal gammopathy of undetermined significance was diagnosed in one case. Although one patient with focal segmental glomerulosclerosis developed renal failure, all others exhibited stable renal function. Monoclonal IgG TBMID in the native kidney is not associated with renal prognosis. However, this may be an interesting immunopathological finding that would help clarify the pathogenesis of TBM immune deposits. Further study for both monoclonal and polyclonal TBMID is required in the future.     

三种因素对根管桩道预备后根尖封闭性影响的研究

目的:评价根管形态、根管充填方法、根管封闭剂三种因素对桩道预备后根管的根尖封闭性的影响。方法:本实验共选取45颗规则的直根管牙根及40颗椭圆形根管牙根,分为9组。其中实验组A组为规则的直根管,A1:iRoot SP+热牙胶(n=10),A2:i Root SP+单尖法(n=10),A3:Gutta Flow2+热牙胶(n=10),A4:Gutta Flow2+单尖法(n=10);实验组B组为椭圆形根管,B1:iRoot SP+热牙胶(n=10),B2:i Root SP+单尖法(n=10),B3:Gutta Flow2+热牙胶(n=10),B4:Gutta Flow2+单尖法(n=10);C组为空白对照组,规则的直根管,不作充填(n=5)。实验组充填结束后均行纤维桩桩道预备。使用染料渗透技术评价根尖微渗漏情况,通过扫描电镜观察各组牙本质与根管封闭剂界面的微观形态。结果:A1、A2、A3、A4、B1、B2、B3、B4组分别为(2.97±0.89)、(2.93±1.36)、(0.98±0.68)、(0.99±0.73)、(3.20±1.08)、(3.26±1.17)、(1.10±0.85)、(1.04±0.97)mm,C组渗透根管全长。对结果进行三因素析因设计资料的方差分析显示,根管形态及根管充填方法对根尖封闭性的影响无统计学意义(P>0.05),根管封闭剂对根尖封闭性有显著影响(P<0.05)。扫描电镜观察,使用Gutta Flow2组封闭剂与根管壁的结合较为紧密。结论:对于桩道预备后的根管,根管封闭剂是影响根尖封闭性的主要因素,Gutta Flow2略优于iRoot SP。根管形态、根管充填方法及根管封闭剂三者之间不存在交互作用。     

Cell surface engineering of microorganisms towards adsorption of heavy metals

Abstract

Heavy metal contamination has become a worldwide environmental concern due to its toxicity, non-degradability and food-chain bioaccumulation. Conventional physical and chemical treatment methods for heavy metal removal have disadvantages such as cost-intensiveness, incomplete removal, secondary pollution and the lack of metal specificity. Microbial biomass-based biosorption is one of the approaches gaining increasing attention because it is effective, cheap, and environmental friendly and can work well at low concentrations. To enhance the adsorption properties of microbial cells to heavy metal ions, the cell surface display of various metal-binding proteins/peptides have been performed using a cell surface engineering approach. The surface engineering of Gram-negative bacteria, Gram-positive bacteria and yeast towards the adsorption of heavy metals are reviewed in this article. The problems and future perspectives of this technology are discussed.     

甘肃民乐黄芪品质与土壤关系的研究

目的 研究甘肃民乐黄芪品质与土壤的关系。方法 采集黄芪药材和土壤样品,利用高效液相色谱法、紫外分光光度法、原子吸收分光光度法等测定药材质量、土壤因子及重金属元素。结果 民乐黄芪质量符合药典标准规定,受重金属污染风险低。浸出物与速效钾呈显著负相关;黄芪甲苷与速效钾呈显著正相关;毛蕊异黄酮葡萄糖苷与可溶盐呈极显著正相关,与速效钾呈显著正相关,与pH值呈显著负相关。其中,土壤pH值是影响黄芪浸出物、黄芪甲苷、毛蕊异黄酮葡萄糖苷三者含量的关键因素,其次为全磷、有机质和全氮。结论 研究结果揭示了土壤因子是民乐黄芪品质的主要影响因素,可为民乐县规范化种植黄芪药材提供理论依据。