326 research outputs found

    Lawson topology of the space of formal balls and the hyperbolic topology

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    AbstractLet (X,d) be a metric space and BX=X×R denote the partially ordered set of (generalized) formal balls in X. We investigate the topological structures of BX, in particular the relations between the Lawson topology and the product topology. We show that the Lawson topology coincides with the product topology if (X,d) is a totally bounded metric space, and show examples of spaces for which the two topologies do not coincide in the spaces of their formal balls. Then, we introduce a hyperbolic topology, which is a topology defined on a metric space other than the metric topology. We show that the hyperbolic topology and the metric topology coincide on X if and only if the Lawson topology and the product topology coincide on BX

    FAPlus/FNPlus blood culture bottles

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    Background : The comparison of the performance of FAPlus/FNPlus bottles and combination of SA/SN and FA/FN bottles is not yet reported. Methods : We used human blood samples to investigate microorganism detection rates and the time to positivity (TTP) in a before-vs.-after study (a combination of SA/SN and FA/FN bottles from September 2012 to August 2013 vs. FAPlus/FNPlus bottles from September 2013 to August 2014). Results : The microorganism detection rate was significantly higher in the later period than in the earlier period (11.2% vs. 9.6%, P < 0.001), particularly for Enterococcus and Streptococcus species, nonfermentative Gram-negative bacilli, and Helicobacter cinaedi. TTP for pathogens was longer when FAPlus/FNPlus bottles were used than when a combination of SA/SN and FA/FN bottles was used (14.9 vs. 13.3 h, P = 0.014), particularly, in the case of Gram-negative bacilli including Escherichia coli. Conclusion : The microorganism detection rate was improved with the use of FAPlus/FNPlus bottles compared with the combination of SA/SN and FA/FN bottles ; however, FAPlus/FNPlus bottles seemed to be inferior to SA/SN and FA/FN bottles in terms of TTP

    Effects of prolonged weak anodal direct current on electrocorticogram in awake rabbit.

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    The effects of prolonged weak anodal direct current (DC) on the electrocorticogram (ECoG) were investigated in awake rabbits. When the current (20-40 microA) was applied to the motor region of the cerebral cortex, seizure activity in the ECoG appeared from the frontal cortex. Repeated application of the DC decreased the threshold current for producing the seizure activity. Diazepam significantly elevated the threshold of the seizure activity. In contrast to the marked changes in the ECoG, no behavioral changes were observed during or after the application of weak anodal DC. The changes in the ECoG are discussed in relation to the intensity and duration of the DC.</p

    Total Synthesis of Tiacumicin A. Total Synthesis, Relay Synthesis, and Degradation Studies of Fidaxomicin (Tiacumicin B, Lipiarmycin A3)

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    The commercial macrolide antibiotic fidaxomicin was synthesized in a highly convergent manner. Salient features of this synthesis include a β-selective noviosylation, a β-selective rhamnosylation, a ring-closing metathesis, a Suzuki coupling, and a vinylogous Mukaiyama aldol reaction. Careful choice of protecting groups and fine-tuning of the glycosylation reactions led to the first total synthesis of fidaxomicin. In addition, a relay synthesis of fidaxomicin was established, which gives access to a conveniently protected intermediate from the natural material for derivatization. The first total synthesis of a related congener, tiacumicin A, is presented

    Potential role of vacuolar H+–adenosine triphosphatase in neointimal formation in cultured human saphenous vein

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    AbstractObjective: Vacuolar H+–adenosine triphosphatase plays a pivotal role in pH regulation and molecular transport across the vacuolar membranes and is involved in cell proliferation and transformation. In the present study, possible involvement of vacuolar H+–adenosine triphosphatase in neointimal formation was investigated in an organ culture model of human saphenous vein. Methods and results: Cultured saphenous vein segments developed neointimal formation and marked thickening of the media within 14 days. Neointimal formation and medial thickening were completely inhibited by 10 nmol/L bafilomycin A1, a selective inhibitor of vacuolar H+-adenosine triphosphatase, although structurally related macrolide antibiotics FK-506 and erythromycin were without an effect. The neointimal cells were positive for α-smooth muscle actin and vimentin but negative for desmin, indicative of myofibroblasts. The emergence of myofibroblasts was inhibited, and endothelial cells were preserved in the saphenous vein segments treated with bafilomycin A1. Uptake of bromodeoxyuridine, a proliferation marker, by myofibroblasts was abrogated in the saphenous vein segments treated with 10 nmol/L bafilomycin A1. Detection of apoptotic cells by terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling concomitant with identification of desmin-expressing smooth muscle cells demonstrated that neointimal myofibroblasts, but not medial smooth muscle cells, that expressed desmin underwent apoptosis by treatment with bafilomycin A1. Conclusions: These results suggest that vacuolar H+–adenosine triphosphatase may be involved in myofibroblast growth that contributes to neointimal formation and medial thickening in cultured human saphenous vein. Increased sensitivity of myofibroblasts, but not endothelial cells, and differentiated smooth muscle cells to bafilomycin A1 may have potential therapeutic implications in the treatment for vein graft disease. (J Thorac Cardiovasc Surg 2000;119:998-1007

    Comparative Study of Human Hematopoietic Cell Engraftment into Balb/c and C57BL/6 Strain of Rag-2/Jak3 Double-Deficient Mice

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    Immunodeficient mice are becoming invaluable tools in human stem cell and tumor research. In this study, we generated Rag-2/Jak3 double-deficient (Rag-2−/−Jak3−/−) mice with a C57/BL6 and Balb/c genetic background and compared the human lymphohematopoietic cell engraftment rate. Human cord blood-derived CD34+ hematopoietic stem cells were successfully engrafted into Balb/c Rag-2−/−Jak3−/− mice; however, the engraftment rate was far lower in C57/BL6 Rag-2−/−Jak3−/− mice. Transplantation of human peripheral blood mononuclear cells resulted in the same tendency. Thus, a Balb/c background offers superior engraftment capacity than a C57/BL6 background and provides an attractive model for human hematopoietic cell engraftment

    Age, gender, insulin and blood glucose control status alter the risk of ischemic heart disease and stroke among elderly diabetic patients

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    <p>Abstract</p> <p>Background</p> <p>We analyzed the effects of insulin therapy, age and gender on the risk of ischemic heart disease (IHD) and cerebrovascular accident (CVA) according to glycemic control.</p> <p>Methods and Results</p> <p>We performed a prospective cohort study (Japan Cholesterol and Diabetes Mellitus Study) of type 2 diabetes patients (n = 4014) for 2 years. The primary endpoint was the onset of fatal/non-fatal IHD and/or CVA, which occurred at rates of 7.9 and 7.2 per 1000 person-years, respectively. We divided diabetic patients into four groups based on age (≤ 70 and > 70) and hemoglobin A1C levels (≤ 7.0 and > 7.0%). Multiple regression analysis revealed that IHD was associated with high systolic blood pressure and low HDL-C in patients under 70 years of age with fair glycemic control and was associated with low diastolic blood pressure in the older/fair group. Interestingly, insulin use was associated with IHD in the older/poor group (OR = 2.27, 95% CI = 1.11-5.89; p = 0.026) and was associated with CVA in the older/fair group (OR = 2.09, 95% CI = 1.06-4.25; p = 0.028). CVA was associated with lower HDL-C and longer duration of diabetes in younger/poor glycemic control group. Results by stepwise analysis were similar. Next, patients were divided into four groups based on gender and diabetic control(hemoglobinA1C < or > 7.0%). Multiple regression analysis revealed that IHD was associated with high systolic blood pressure in male/fair glycemic control group, age in male/poor control group, and short duration of diabetic history in females in both glycemic control groups. Interestingly, insulin use was associated with IHD in the male/poor group(OR = 4.11, 95% CI = 1.22-8.12; p = 0.018) and with CVA in the female/poor group(OR = 3.26, 95% CI = 1.12-6.24; p = 0.02). CVA was associated with short duration of diabetes in both female groups.</p> <p>Conclusions</p> <p>IHD and CVA risks are affected by specific factors in diabetics, such as treatment, gender and age. Specifically, insulin use has a potential role in preventing IHD but may also be a risk factor for CVA among the diabetic elderly, thus revealing a need to develop improved treatment strategies for diabetes in elderly patients. The Japan Cholesterol and Diabetes Mellitus Study was formulated to evaluate them(Umin Clinical Trials Registry, clinical trial reg. no. UMIN00000516; <url>http://www.umin.ac.jp/ctr/index.htm</url>).</p
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