Experimental evaluation of flow patterns in interposition vein cuff anastomosis. The influence of non-planarity of the inflow

Clinical evidence suggests that the development of myointimal hyperplasia in prosthetic femorodistal bypass grafts may be reduced by the interposition of a cuff of autologous vein between the graft and the recipient artery. Previous experimental work has shown that some of the benefits may be attributed to the geometry of the cuffed anastomosis. Since the distal anastomosis in vivo is often non-planar we have carried out a preliminary study in a model where the graft is at an angle of 45 degrees to the anterior-posterior plane of the anastomosis. This out-of-plane angulation produces highly asymmetric flow patterns in the anastomosis with significant flow separation on the ipsilateral side of the cuff. In the proximal and distal outflow, however, the velocity vectors show significant helical motion with temporal instability in the distal outflow.     

Genome constitution for Musa beccarii (Musaceae) varieties

Borneo is a large island in Southeast Asia. It is divided politically into three parts: the kingdom of Brunei on the north central coast; the Malaysian states of Sarawak and Sabah to the west and east; with Kalimantan of Indonesia making up the larger par…     

Developing a Prognostic Micro-RNA Signature for Human Cervical Carcinoma

Cervical cancer remains the third most frequently diagnosed and fourth leading cause of cancer death in women worldwide. We sought to develop a micro-RNA signature that was prognostic for disease-free survival, which could potentially allow tailoring of treatment for cervical cancer patients. A candidate prognostic 9-micro-RNA signature set was identified in the training set of 79 frozen specimens. However, three different approaches to validate this signature in an independent cohort of 87 patients with formalin-fixed paraffin-embedded (FFPE) specimens, were unsuccessful. There are several challenges and considerations associated with developing a prognostic micro-RNA signature for cervical cancer, namely: tumour heterogeneity, lack of concordance between frozen and FFPE specimens, and platform selection for global micro-RNA expression profiling in this disease. Our observations provide an important cautionary tale for future miRNA signature studies for cervical cancer, which can also be potentially applicable to miRNA profiling studies involving other types of human malignancies.     

Flow patterns in an endovascular stent-graft for abdominal aortic aneurysm repair

Endovascular exclusion of the abdominal aortic aneurysm (AAA) has been carried out in selected patients during the past decade. The deployment of a complex multicomponent endovascular device in an aneurysmal aorta may alter the local haemodynamics and lead to thrombosis and intimal hyperplasia development. The aim of this in vitro study was to investigate the flow patterns using flow visualisation and laser Doppler anemometry in a commercial bifurcated stent-graft. Two configurations of the stent-graft, endo-stent and exo-stent, were investigated in an idealised planar AAA model. The flow structures in the main trunk in both configurations of the stent-graft are three-dimensional with complex secondary structures. However, these flow structures were not entirely caused by the stent-graft. The stent struts in the endo-stent configuration cause localised alteration in the flow pattern but the overall flow structures were not significantly affected. Low velocity regions in the main trunk and flow separation in the stump region and the curved segment of the iliac limbs were observed. These areas are associated with thrombosis in the clinical situation. Improvements in the design of endovascular devices may remove these areas of unfavourable flow patterns and lead to better clinical performance.     

Uncertainty in cancer risk at low doses of inorganic arsenic

It is unknown whether inorganic arsenic in drinking water concentrations at the current maximum contaminant level of 50 μg/1 poses a cancer risk in the United States. Data from two large epidemiological studies of cancer and arsenic in drinking water in Taiwan indicate a dose‐response relationship, but the magnitude of risk at low concentrations is highly uncertain. Four sources of uncertainty are described: model choice, data aggregation, intra‐village variability of arsenic in well water, arsenic intake from food. New data from an appropriately designed epidemiological study are needed to improve dose‐response assessment.     

Adaptation of the cockroach Blattella germanica to human habitats: circadian and noncircadian factors

To survive, an animal must respond to the environmental stimuli (Zeitgebers) precisely coinciding with a 24‐h light/dark cycle. In human habitats, both natural and artificial Zeitgebers intermingle, entraining the circadian clocks of animals. Whether a circadian clock can respond to Zeitgebers effectively is closely related to the level of adaptive competitiveness. In the present review, the German cockroach (Blattella germanica L.) is compared with the double‐striped cockroach (Blattella bisignata Brunner von Wattenwyl) and the reasons why B. germanica is a more competitive dweller than its sibling species in human habitats are discussed. For example, sensitive adjustment of circadian clocks allows a male B. germanica to coordinate itself to the changes of daily light/dark cycles more efficiently; by contrast, it takes male B. bisignata more than 3 days to adjust. In a given dark phase, male B. germanica appear more to be resistant than B. bisignata to interference from light pulses. Ovary‐dependent masking factors enable female B. germanica to take advantage of the light phase to feed or mate, during which time a female B. bisignata typically remains inert. Furthermore, the gregariousness levels, fertilization and hatching rates, as well as mating behaviours of both cockroach species are compared. All of these comparisons suggest that B. germanica surpasses B. bisignata with respect to adapting to the artificial constraints within human habitats as a result of the adoption of an integrated strategy consisting of circadian and noncircadian approaches.     

Copper complex derived from <Emphasis Type="Italic">S</Emphasis>-benzyldithiocarbazate and 3-acetylcoumarin induced apoptosis in breast cancer cell

Copper complexes have been widely studied for the anti-tumour application as cancer cells are reported to take up greater amounts of copper than normal cells. Preliminary study revealed that the newly synthesised copper complex [Cu(SBCM)₂] displayed marked anti-proliferative towards triple-negative MDA-MB-231 breast cancer cells. Therefore, Cu(SBCM)₂ has great potential to be developed as an agent for the management of breast cancer. The present study was carried out to investigate the mode of cell death induced by Cu(SBCM)₂ towards MDA-MB-231 breast cancer cells. The inhibitory and morphological changes of MDA-MB-231 cells treated with Cu(SBCM)₂ was determined by using MTT assay and inverted light microscope, respectively. The safety profile of Cu(SBCM)₂ was also evaluated towards human dermal fibroblast (HDF) normal cells. Confirmation of apoptosis and cell cycle arrest were determined by flow cytometry analysis. The expression of p53, Bax, Bcl-2 and MMP2 protein were detected with western blot analysis. Cu(SBCM)₂ significantly inhibited the growth of MDA-MB-231 cells in a dose-dependent manner with GI₅₀ 18.7?±?3.06 µM. Indeed, Cu(SBCM)₂ was less toxic towards HDF normal cells with GI₅₀ 31.8?±?4.0 µM. Morphological study revealed that Cu(SBCM)₂-treated MDA-MB-231 cells experienced cellular shrinkage, membrane blebbing, chromatin condensation and formation of apoptotic bodies, suggesting that Cu(SBCM)₂ induced apoptosis in the cells, which was confirmed by Annexin-V/PI flow cytometry analysis. It was also found that Cu(SBCM)₂ induced G₂/M phase cell cycle arrest towards MDA-MB-231 cells. The induction of apoptosis and cell cycle arrest in the present study is possibly due to the down-regulation of the mutant p53 and MMP2 protein. In conclusion, Cu(SBCM)₂ can be developed as a targeted therapy for the treatment of triple-negative breast cancer.     

蓖麻蚕γ-谷氨酰转肽酶的研究

L-γ-谷氨酰转肽酶(γ-GTP)广泛分布在蓖麻蚕Philosamia cynthia ricinI的中肠、马氏管、后丝腺、脂肪体、体壁等组织中;并存在于蚕个体发育中的各个阶段。酶活力以马氏管、中肠为最大。在五龄蚕前中期各组织均显示γ-GTP最大活力。在脂肪体和表皮组织中,蛹形成时又分别出现γ-GTP活力峰。昆虫生长发育必需的10种氨基酸均是蚕各组织γ-GTP酶促反应的受体。这些结果表明,γ-GTP作为L-γ-谷氨酰循环中一个关键酶,在蓖麻蚕体内对氨基酸的吸收和转运起着重要作用。