双色FISH和DNA纤维FISH方法的建立与应用

在构建了含毛细胞白血病相关的结构性倒位inv (5) (p13.1q13.3)的细胞系后,为了确定该新建细胞系在建株过程中其倒位断裂点关键区遗传物质是否发生改变,以生物素或地高辛标记的cCI5-216 和cCI5-267黏粒DNA为探针,进行染色体中期、间期和DNA纤维3种双色荧光原位杂交的分析。结果表明：该新建细胞系的3种双色荧光原位杂交结果,均与该细胞系的原代细胞的完全相同,证实了该细胞系倒位断裂点关键区的遗传物质结构未发生改变。该细胞系是揭示毛细胞白血病发病的分子机理的重要研究材料。     

Inhibition of Abeta production and APP maturation by a specific PKA inhibitor

Alzheimer's disease is characterized pathologically by extracellular amyloid beta protein (Abeta) deposition in the brain. The Abeta peptide, a 39-42 amino acid fragment, is derived from defined proteolysis of the amyloid precursor protein (APP) [Glenner et al., Appl. Pathol. 2 (1984) 357-369; Selkoe, Neuron 6 (1991) 487-498] and is the primary component of senile plaques. Although it is known that intracellular APP is subjected to posttranslational modification, the molecular mechanism that regulates the APP processing is not completely clear. In the present study, we demonstrates that H89, a specific inhibitor for cAMP dependent protein kinase A (PKA), inhibits Abeta production and APP secretion in a dose dependent manner in cells stably transfected with human APP bearing a 'Swedish mutation'. Concurrent with the effect, H89 inhibits C-terminal fragment of the APP. We also found that the PKA inhibitor abolishes the mature form of intracellular APP and accumulates the immature form. Finally, direct administration of H89 into brains of transgenic mice overexpressing human APP shows that the compound inhibits Abeta production in the hippocampal region. Our data suggests that PKA plays an important role in the maturation of APP associated with APP processing.     

Microtubule-dependent retrograde transport of proteins into the ER in the presence of brefeldin A suggests an ER recycling pathway

Characteristics of brefeldin A (BFA)-induced redistribution of Golgi proteins into the endoplasmic reticulum (ER) and its relationship to an ER retrieval pathway were investigated. Retrograde movement of Golgi proteins into the ER occurred via long, tubulovesicular processes extending out of the Golgi along microtubules. Microtubule-disrupting agents (i.e., nocodazole), energy poisons, and reduced temperatures inhibited this pathway. In BFA-treated cells Golgi proteins appeared to cycle between the ER and an intermediate compartment marked by a 53 kd protein. Addition of nocodazole disrupted this dynamic cycle by preferentially inhibiting retrograde movement, causing Golgi proteins to accumulate in the intermediate compartment. In the absence of BFA, such an ER cycling pathway appeared to be followed normally by the 53 kd protein but not by Golgi proteins, as revealed by temperature shift experiments. We propose that BFA induces the interaction of the Golgi with an intermediate "recycling" compartment that utilizes a microtubule-dependent pathway into the ER.     

Association between variants of EXT2 and type 2 diabetes: a replication and meta-analysis

Recent publications have found an association between variants of exostosin 2 (EXT2) gene and the risk of type 2 diabetes in some population but not in others. In an attempt to address these inconsistencies, we investigated EXT2 variants in two independent cohorts, and conducted a literature-based meta-analysis. Through regression model, we assessed the relationship between the EXT2 single nucleotide polymorphisms (SNPs) (rs3740878, rs11037909 and rs1113132) and the risk of type 2 diabetes in Han Chinese population, including a total of 2,533 cases and 2,643 controls. We combined our data with that from previously published studies and performed a meta-analysis to evaluate the effect size of the gene. Consistent with some studies, we found marginal association for the rs3740878 (OR = 1.07, 95 % CI = 0.99, 1.16, p = 0.09), rs11037909 (OR = 1.07, 95 % CI = 0.99, 1.16, p = 0.08), and rs1113132 (OR = 1.08, 95 % CI = 1.00, 1.17, p = 0.06) in our 2 cohorts. Meta-analysis, comprising 9,224 type 2 diabetes and 10,484 controls, revealed that three SNPs (rs3740878, rs11037909 and rs1113132) in EXT2 were significantly associated with type 2 diabetes (ORs range from 1.06 to 1.07, p = 0.038, p = 0.008 and p = 0.005, respectively). Variation in the EXT2 locus appears to be associated with a small increase in the risk of type 2 diabetes. However, well-designed prospective studies with larger sample size and more ethnic groups are needed to further validate the results.     

Atrial Arrhythmia in Ageing Spontaneously Hypertensive Rats: Unraveling the Substrate in Hypertension and Ageing

Background

Both ageing and hypertension are known risk factors for atrial fibrillation (AF) although the pathophysiological contribution or interaction of the individual factors remains poorly understood. Here we aim to delineate the arrhythmogenic atrial substrate in mature spontaneously hypertensive rats (SHR).

Methods

SHR were studied at 12 and 15 months of age (n = 8 per group) together with equal numbers of age-matched normotensive Wistar-Kyoto control rats (WKY). Electrophysiologic study was performed on superfused isolated right and left atrial preparations using a custom built high-density multiple-electrode array to determine effective refractory periods (ERP), atrial conduction and atrial arrhythmia inducibility. Tissue specimens were harvested for structural analysis.

Results

Compared to WKY controls, the SHR demonstrated: Higher systolic blood pressure (p<0.0001), bi-atrial enlargement (p<0.05), bi-ventricular hypertrophy (p<0.05), lower atrial ERP (p = 0.008), increased atrial conduction heterogeneity (p = 0.001) and increased atrial interstitial fibrosis (p = 0.006) & CD68-positive macrophages infiltration (p<0.0001). These changes resulted in higher atrial arrhythmia inducibility (p = 0.01) and longer induced AF episodes (p = 0.02) in 15-month old SHR. Ageing contributed to incremental bi-atrial hypertrophy (p<0.01) and atrial conduction heterogeneity (p<0.01) without affecting atrial ERP, fibrosis and arrhythmia inducibility. The limited effect of ageing on the atrial substrate may be secondary to the reduction in CD68-positive macrophages.

Conclusions

Significant atrial electrical and structural remodeling is evident in the ageing spontaneously hypertensive rat atria. Concomitant hypertension appears to play a greater pathophysiological role than ageing despite their compounding effect on the atrial substrate. Inflammation is pathophysiologically linked to the pro-fibrotic changes in the hypertensive atria.     

Effects of ROS and caspase-3-like protein on the growth and aerenchyma formation of Potamogeton perfoliatus stem

Protoplasma - Aerenchyma formation plays an important role in the survival of Potamogeton perfoliatus in submerged environment. To understand the regulatory role of reactive oxygen species (ROS)...     

Development of a novel feeding regime for large scale production of human umbilical cord mesenchymal stem/stromal cells

Cytotechnology - Human umbilical cord mesenchymal stem/stromal cells (hUC-MSCs) have attracted significant research interests in regenerative medicine and cell-based therapies due to their...     

Glucose biosensor based on electrodeposited platinum nanoparticles and three-dimensional porous chitosan membranes

The chitosan with three-dimensional porous structure greatly increased the effective electrode surface for loading of platinum nanoparticles and promoted efficient electron transfer. The resulting biosensor had a response time (within 5 s) and a linear response from 6 μM to 4.2 mM glucose with a detection limit of 2 μM (S/N = 3). Moreover, the methodology can be applied for the immobilization of other enzymes.