烤烟根系分泌物中单糖的组分含量及其相关分析

以4个不同烤烟品种为研究材料,采用盆栽试验,运用高效毛细管区带电泳法测定各品种根际土、非根际土、根系及叶片中的单糖组分及含量,并分析其相关关系,探究根系分泌物中糖类的分泌特性。结果表明：在各样品中,共检出木糖、葡萄糖、半乳糖、核糖、阿拉伯糖和鼠李糖6种糖;不同品种根际土、非根际土、根系及叶片中检出的糖组分及含量均存在差异;同一品种中,叶片最高,根系次之,根际土和非根际土最低;相关性分析表明,木糖、阿拉伯糖、葡萄糖、鼠李糖和半乳糖总量在根际土、非根际土、叶片和根系间呈正相关关系,各单糖组分间均呈正相关关系,部分组分呈显著或极显著相关关系。研究表明,不同烤烟品种根系分泌这些单糖存在品种差异,且根系分泌单糖可能是一个沿浓度梯度的扩散过程。     

胃肝样腺癌的临床病理特征

目的探讨胃肝样腺癌（hepatoid adenocarcinoma of the stomach,HAS）的临床病理学特点、发生机制和免疫组化特征,以提高诊断水平。方法收集并分析5例胃肝样腺癌的临床特征和病理资料,采用HE染色、免疫组化方法,并复习文献。结果组织学胃肝样腺癌具有管状腺癌、粘液性癌和肝样分化腺癌的移行过渡,肿瘤细胞呈小梁状、巢团状,间质为丰富的血窦。免疫表型胃肝样腺癌AAT（5／5）、ACT（5／5）、CEA（5／5）、AFP（4／5）均为阳性,Heppar1灶性阳性（2／5）。结论胃肝样腺癌是一种少见的高度恶性、侵袭性强的特殊类型胃癌,组织学呈肝细胞样腺癌,免疫表型AFP、AAT和ACT阳性有助诊断。     

Vero细胞和脊髓灰质炎病毒在无血清条件下的培养探究

目的：探索Vero细胞和脊髓灰质炎病毒在无血清条件下的最佳培养条件,为无血清培养Vero细胞生产脊髓灰质炎疫苗奠定基础。方法选择直接适应（直降组）和序贯适应（驯化组）两种无血清培养方法,观察Vero细胞和脊髓灰质炎病毒在无血清条件下的生长情况,并检测脊髓灰质炎病毒及其病毒滴度。结果 Vero细胞在两种无血清条件下均生长良好,其中驯化组细胞生长速度更接近对照组。以脊髓灰质炎病毒Sabin株Ⅰ型分别感染直降组、驯化组和对照组细胞的病毒滴度平均值分别为8．94、8．81和8．94 LgCCID50/mL;Ⅱ型病毒滴度平均值分别为8．84、8．25和7．94 LgCCID50/mL;Ⅲ型病毒滴度平均值分别为8．91、8．57和8．63 LgCCID50/mL;且3组的变异系数（ CV）均小于10％。结论 Vero细胞在无血清条件下生长良好,无血清培养的Vero 细胞可用作脊髓灰质炎疫苗生产的基质。     

Ischemic Preconditioning Increases Endothelial Progenitor Cell Number to Attenuate Partial Nephrectomy-Induced Ischemia/Reperfusion Injury

Objectives

The objective of this study was to investigate the role of endothelial progenitor cells (EPCs) in the modulation of ischemia-reperfusion injury (IRI) in a partial nephrectomy (PN) rat model using early-phase ischemic preconditioning (IPC).

Materials and Methods

Ninety male Sprague-Dawley rats were randomly divided into three groups following right-side nephrectomy: Sham-operated rats (surgery without vascular clamping); PN rats (renal blood vessels were clamped for 40 min and PN was performed); and IPC rats (pretreated with 15 min ischemia and 10 min reperfusion). At 1, 3, 6, 12, 24 h, and 3 days after reperfusion, the pool of circulating EPCs and kidneys were harvested. The extent of renal injury was assessed, along with EPC number, cell proliferation, angiogenesis, and vascular growth factor expression.

Results

Pretreated rats exhibited significant improvements in renal function and morphology. EPC numbers in the kidneys were increased at 12 h following reperfusion in the IPC group as compared to the PN or Sham groups. Cell proliferation (including endothelial and tubular epithelial cells) and angiogenesis in peritubular capillaries were markedly increased in kidneys treated with IPC. In addition, vascular endothelial growth factor-A (VEGF-A) and stromal cell-derived factor-1α (SDF-1α) expression in the kidneys of pretreated rats was increased compared to rats subjected to PN.

Conclusions

Our investigation suggested that: (1) the early phase of IPC may attenuate renal IRI induced by PN; (2) EPCs play an important role in renal protection, involving promotion of cell proliferation and angiogenesis through release of several angiogenic factors.     

Time Course of Current of Injury Is Related to Acute Stability of Active-Fixation Pacing Leads in Rabbits

Background

Magnitude of current of injury (COI) consequent to pacemaker lead fixation is recognized as a predictor of acute lead stability. It is unclear whether dynamic monitoring of COI after lead fixation provides additional information beyond a single assessment performed at the time of fixation.

Objectives

This study was aimed to test the hypothesis that the time course of COI is related to acute lead stability.

Methods and Results

Active fixation leads with fixed screw were anchored to either Langendorff-perfused rabbit hearts endocardially or in vivo hearts epicardially in manners of contact the helix with no rotation, half rotation and full rotation, respectively. Intracardiac electrogram (EGM) was monitored dynamically from onset to resolution of COI, and magnitudes of intrinsic R wave and COI, including ST-segment elevation, ST/R and intracardiac EGM duration (IED), were measured. A digital force gauge was applied to assess lead stability. In vitro, COI in contacted leads was significantly smaller than those in half rotated (p<0.05) and fully rotated leads (p<0.05), and presented most precipitous recovery to baseline (1.5±1.1 min, p<0.05). Half-rotated and fully rotated leads manifested the same magnitude of COI right after placement. However, the time course of COI was significantly longer in fully rotated leads than that in half rotated leads (26.5±2.8 min vs. 5.6±2.0 min, p<0.05). Similar findings were observed in vivo. The time course of COI was significantly correlated with the force needed to detach the lead from myocardium (r = 0. 72, n = 48, p<0.001).

Conclusions

Time course of COI is related to acute lead stability in rabbits. One might be misled by a single assessment of COI magnitude right after lead placement, whereas persistence of COI is likely to be a useful indicator of adequate lead stability.     

A Luminex Assay Detects Amyloid β Oligomers in Alzheimer’s Disease Cerebrospinal Fluid

Amyloid beta (aβ) protein assembles into larger protein aggregates during the pathogenesis of Alzheimer’s disease (AD) and there is increasing evidence that soluble aβ oligomers are a critical pathologic species. Diagnostic evaluations rely on the measurement of increased tau and decreased aβ42 in the cerebrospinal fluid (CSF) from AD patients and evidence for oligomeric aβ in patient CSF is conflicting. In this study, we have adapted a monoclonal single antibody sandwich ELISA assay to a Luminex platform and found that this assay can detect oligomerized aβ42 and sAPPα fragments. We evaluated oligomeric aβ reactivity in 20 patients with AD relative to 19 age matched controls and compared these values with a commercially available Alzbio3 kit that detects tau, phosphorylated tau and aβ42 on the same diagnostic platform. We found that CSF samples of patients with AD had elevated aβ oligomers compared to control subjects (p < 0.05) and the ratio of aβ oligomers to aβ42 was also significantly elevated (p < 0.0001). Further research to develop high sensitivity analytical platforms and rigorous methods of developing stable assay standards will be needed before the analysis of oligomeric aβ becomes a routine diagnostic assay for the evaluation of late onset AD patients.     

Two-Component System Response Regulators Involved in Virulence of Streptococcus pneumoniae TIGR4 in Infective Endocarditis

Streptococci resident in the oral cavity have been linked to infective endocarditis (IE). While other viridans streptococci are commonly studied in relation to IE, less research has been focused on Streptococcus pneumoniae. We established for the first time an animal model of S. pneumoniae IE, and examined the virulence of the TIGR4 strain in this model. We hypothesized that two-component systems (TCS) may mediate S. pneumoniae TIGR4 strain virulence in IE and examined TCS response regulator (RR) mutants of TIGR4 in vivo with the IE model. Thirteen of the 14 RR protein genes were mutagenized, excluding only the essential gene SP_1227. The requirement of the 13 RRs for S. pneumoniae competitiveness in the IE model was assessed in vivo through use of quantitative real-time PCR (qPCR) and competitive index assays. Using real-time PCR, several RR mutants were detected at significantly lower levels in infected heart valves compared with a control strain suggesting the respective RRs are candidate virulence factors for IE. The virulence reduction of the ΔciaR mutant was further confirmed by competitive index assay. Our data suggest that CiaR is a virulence factor of S. pneumoniae strain TIGR4 for IE.     

Homeostatic Properties and Phenotypic Maturation of Murine CD4+ Pre-Thymic Emigrants in the Thymus

After a tightly regulated developmental program in the thymus, “mature” single positive (SP) thymocytes leave the thymus and enter the periphery. These newly arrived recent thymic emigrants (RTEs) are phenotypically and functionally immature, and will complete a dynamic maturation in the peripheral lymphoid organs before being licensed to be resident naïve T cells. To study the early events occurring in the RTE maturation process, we identified the phenotype of CD4⁺ pre-RTEs, a population of CD4⁺ SP thymocytes that have acquired the thymus egress capability. Compared to peripheral naïve T cells, CD4⁺ pre-RTEs displayed superior survival capability in lymphoreplete mice and faster proliferation under lymphopenic condition. The differences in Bcl2/Bim expression and/or heightened IL-7 signaling pathway may account for the pre-RTEs’ better responsiveness to homeostatic signals. Qa2, the expression of which indicates the phenotypic maturation of SPs and RTEs, was found to be upregulated in CD4⁺ pre-RTEs in thymic perivascular space. Migratory dendritic cells that surround this region contribute to Qa2 expression in pre-RTEs. The dendritic cell-driven Qa2 induction of CD4⁺ pre-RTEs is independent of MHC class II and Aire molecules.     

Impairment of Endothelial-Myocardial Interaction Increases the Susceptibility of Cardiomyocytes to Ischemia/Reperfusion Injury

Endothelial-myocardial interactions may be critically important for ischemia/reperfusion injury. Tetrahydrobiopterin (BH₄) is a required cofactor for nitric oxide (NO) production by endothelial NO synthase (eNOS). Hyperglycemia (HG) leads to significant increases in oxidative stress, oxidizing BH₄ to enzymatically incompetent dihydrobiopterin. How alterations in endothelial BH₄ content impact myocardial ischemia/reperfusion injury remains elusive. The aim of this study was to examine the effect of endothelial-myocardial interaction on ischemia/reperfusion injury, with an emphasis on the role of endothelial BH₄ content. Langendorff-perfused mouse hearts were treated by triton X-100 to produce endothelial dysfunction and subsequently subjected to 30 min of ischemia followed by 2 h of reperfusion. The recovery of left ventricular systolic and diastolic function during reperfusion was impaired in triton X-100 treated hearts compared with vehicle-treated hearts. Cardiomyocytes (CMs) were co-cultured with endothelial cells (ECs) and subsequently subjected to 2 h of hypoxia followed by 2 h of reoxygenation. Addition of ECs to CMs at a ratio of 1∶3 significantly increased NO production and decreased lactate dehydrogenase activity compared with CMs alone. This EC-derived protection was abolished by HG. The addition of 100 µM sepiapterin (a BH₄ precursor) or overexpression of GTP cyclohydrolase 1 (the rate-limiting enzyme for BH₄ biosynthesis) in ECs by gene trasfer enhanced endothelial BH₄ levels, the ratio of eNOS dimer/monomer, eNOS phosphorylation, and NO production and decreased lactate dehydrogenase activity in the presence of HG. These results demonstrate that increased BH₄ content in ECs by either pharmacological or genetic approaches reduces myocardial damage during hypoxia/reoxygenation in the presence of HG. Maintaining sufficient endothelial BH₄ is crucial for cardioprotection against hypoxia/reoxygenation injury.