Angiotensin II activates H+-ATPase in type A intercalated cells

We reported previously that angiotensin II (AngII) increases net Cl(-) absorption in mouse cortical collecting duct (CCD) by transcellular transport across type B intercalated cells (IC) via an H(+)-ATPase-and pendrin-dependent mechanism. Because intracellular trafficking regulates both pendrin and H(+)-ATPase, we hypothesized that AngII induces the subcellular redistribution of one or both of these exchangers. To answer this question, CCD from furosemide-treated mice were perfused in vitro, and the subcellular distributions of pendrin and the H(+)-ATPase were quantified using immunogold cytochemistry and morphometric analysis. Addition of AngII in vitro did not change the distribution of pendrin or H(+)-ATPase within type B IC but within type A IC increased the ratio of apical plasma membrane to cytoplasmic H(+)-ATPase three-fold. Moreover, CCDs secreted bicarbonate under basal conditions but absorbed bicarbonate in response to AngII. In summary, angiotensin II stimulates H(+) secretion into the lumen, which drives Cl(-) absorption mediated by apical Cl(-)/HCO(3)(-) exchange as well as generates more favorable electrochemical gradient for ENaC-mediated Na(+) absorption.     

The FRED Flow-Diverter Stent for Intracranial Aneurysms: Clinical Study to Assess Safety and Efficacy

BACKGROUND AND PURPOSE:Flow-diverter stents are emerging for the endovascular treatment of difficult-to-treat or otherwise untreatable cerebral aneurysms (wide-neck, fusiform, dissecting, blisterlike, or giant). We assessed the clinical safety and efficacy of the Flow-Redirection Endoluminal Device.MATERIALS AND METHODS:This was an institutional review board–approved single-center observational clinical study in 29 patients with 34 aneurysms elected to be treated by endovascular intervention. After providing informed consent, patients were included according to the following criteria: aneurysm fundus-to-neck ratio <2 or neck diameter >4 mm, fusiform, dissecting, or giant aneurysms. The primary end point for clinical safety was the absence of death, absence of major or minor stroke, and absence of transient ischemic attack. The primary end point for treatment efficacy was complete angiographic occlusion according to the O''Kelly Marotta grading scale immediately after the procedure and at follow-up after 3 and 6 months (O''Kelly Marotta D: complete occlusion).RESULTS:The Flow-Redirection Intraluminal Device deployment was technically successful in all cases. In 26/29 (89%) of patients, the primary end point of safety was reached; in the 3 remaining patients, 1 disabling ischemic stroke and 2 minor strokes with complete recovery at follow-up were observed. Angiographic (DSA and MRA) and clinical follow-up were available after 3 months in 29/29 (100%) and after 6 months in 25/29 (86%) patients (after 6 months, only MRA follow-up was performed according to our study protocol and institutional standard). At 3-month follow-up, complete occlusion was reached in 19/34 aneurysms (O''Kelly Marotta D: 19/34; 56%). At 6-month follow-up, aneurysm occlusion was complete in 22/30 aneurysms (O''Kelly Marotta D: 22/30; 73%).CONCLUSIONS:Deployment of the Flow-Redirection Intraluminal Device flow-diverter stent is safe and effective in the treatment of difficult-to-treat or otherwise untreatable intracranial aneurysms.

Endovascular treatment of intracranial aneurysms by coiling has become an accepted alternative to surgical clipping, with increasing evidence for lower morbidity and mortality rates, especially in clinical equipoise.^1–3 However, especially in wide-neck, fusiform, dissecting, and giant aneurysms, incomplete coiling and reperfusion are still a major limitation preventing stable long-term occlusion. Aneurysm recanalization and/or neck remnants may be observed despite further refinement in coil technology such as coated platinum coils⁴ and/or procedural modification such as the balloon-remodeling technique⁵ or stent-assisted coil embolization.⁶The development of flow-diverter (FD) stents has offered the potential of aneurysm occlusion through thrombosis triggered by the disruption of flow into the aneurysm sac.^7–16 As a key element of construction, these stents have a braided mesh with a densely covered surface. Once the FD is expanded to cover the aneurysm neck, thrombosis is induced by stasis of flow within the aneurysmal sac. The porosity of the FD mesh and the pressure gradient between parent and smaller adjacent branch vessels preserve flow and patency of the latter even if covered. The Flow-Redirection Endoluminal Device (FRED; MicroVention, Tustin, California) is a new generation of FDs for reconstruction of the parent artery and aneurysm occlusion. Its unique dual-layer design composed of a low-porosity inner mesh and a high-porosity outer stent may provide potential advantages over other available FDs in safe deliverability and effective occlusion of the target lesion. We report our analysis of the clinical safety and efficacy of the FRED in 29 patients with 34 aneurysms.     

Peak bone mineral density in Vietnamese women

Summary

This cross-sectional study showed that peak bone mineral density in Vietnamese women is comparable to that in Caucasian women; however, the prevalence of osteoporosis in post-menopausal Vietnamese women was slightly higher than in Caucasian women. The age of achieving peak bone mass in Vietnamese women was between 26 and 30 years.

Introduction

While peak bone mass and its determinants have been well-documented in Caucasian populations, little has been studied in Asian populations. The present study was designed to estimate the peak bone mineral density (BMD), age of its attainment, and to examine the prevalence of osteoporosis in Vietnamese women aged 50+.

Methods

The study was designed as a cross-sectional study with 328 women aged between 10 and 65 years (average age: 41) who were randomly selected from two districts around Hanoi city according to a stratified sampling scheme. BMD at the lumbar spine, femoral neck and total hip was measured by a DXA instrument (GE Lunar Prodigy, WI, USA). BMD was modeled as a cubic function of age, from which peak BMD and age at peak BMD were estimated. Bootstrap method was utilized to estimate the 95% confidence interval of peak BMD and age at peak BMD. From the peak BMD, T-score was calculated for each woman, and using the World Health Organization criteria, any woman with femoral neck BMD T-score ≤ -2.5 was classified as having osteoporosis.

Results

Peak BMD was estimated at 1.16 g/cm² (standard deviation [SD]: 0.13 g/cm²) at the lumbar spine, 1.02 g/cm² (SD 0.12) at the total hip, and 0.94 g/cm² (SD 0.11) at the femoral neck. In the cubic polynomial model, the age at peak BMD was estimated to range between 27 and 29 years. The prevalence of osteoporosis among those aged between 50 and 65 years was 23%. This prevalence was higher than in Chinese, Japanese, Korean and Caucasian populations.

Conclusion

These data suggest that although the peak BMD in Vietnamese women is comparable to, the prevalence of osteoporosis is higher than, in some other Asian and Caucasian women. It seems that osteoporosis is an important public health burden in Vietnam.     

Effect of chitosan particles and dexamethasone on human bone marrow stromal cell osteogenesis and angiogenic factor secretion

Chitosan is a polysaccharide scaffold used to enhance cartilage repair during treatments involving bone marrow stimulation, and it is reported to increase angiogenesis and osteogenesis in vivo. Here, we tested the hypotheses that addition of chitosan particles to the media of human bone marrow stromal cell (BMSC) cultures stimulates osteogenesis by promoting osteoblastic differentiation and by favoring the release of angiogenic factors in vitro. Confluent BMSCs were cultured for 3 weeks with 16% fetal bovine serum, ascorbate-2-phosphate and disodium β-glycerol phosphate, in the absence or presence of dexamethasone, an anti-inflammatory glucocorticoid commonly used as an inducer of BMSC osteoblast differentiation in vitro. As expected, dexamethasone slowed cell division, stimulated alkaline phosphatase activity and enhanced matrix mineralization. Added chitosan particles accumulated intra- and extracellularly and, while not affecting most osteogenic features, they inhibited osteocalcin release to the media at day 14 and interfered with mineralized matrix deposition. Interestingly, dexamethasone promoted cell attachment and suppressed the release and activation of matrix metalloprotease-2 (MMP-2). While chitosan particles had no effect on the release of angiogenic factors, dexamethasone significantly inhibited (p < 0.05 to p < 0.0001) the release of vascular endothelial growth factor (VEGF), granulocyte-macrophage colony stimulating factor (GM-CSF), tumor necrosis factor-alpha (TNF-α), interleukins 1β, 4, 6, and 10 (IL-1β, IL-4, IL-6, IL-10), and a host of other inflammatory factors that were constitutively secreted by BMSCs. These results demonstrate that chitosan particles alone are not sufficient to promote osteoblast differentiation of BMSCs in vitro, and suggest that chitosan promotes osteogenesis in vivo through indirect mechanisms. Our data further show that continuous addition of dexamethasone promotes osteoblastic differentiation in vitro partly by inhibiting gelatinase activity and by suppressing inflammatory cytokines which result in increased cell attachment and cell cycle exit.     

Probiotics: sorting the evidence from the myths

Probiotics consist of yeast or bacteria, especially lactic acid bacteria. They are available as capsules, powder, fermented milks or yoghurts. Probiotics exhibit strain-specific differences in their resistance to acid and bile, ability to colonise the gastrointestinal tract, clinical efficacy, and benefits to the health of the host. There is level I evidence for the use of probiotics in treating acute infectious diarrhoea and preventing antibiotic-associated diarrhoea, with Lactobacillus rhamnosus GG and Saccharomyces boulardii having the most evidence to support their use for these conditions. There is level II evidence that S. boulardii combined with high-dose vancomycin is more effective than the antibiotic alone in preventing recurrent Clostridium difficile diarrhoea. There is level I evidence that probiotics prevent traveller's diarrhoea. There is level I evidence for use of the high-potency probiotic VSL#3 in preventing pouchitis, and level II evidence for this agent in preventing relapse in patients with ulcerative colitis. Probiotics are generally regarded as safe and well tolerated. Some probiotics may be contraindicated in patients who are immunocompromised or have severe underlying illness, as they have been reported to cause fungaemia and bacteraemia.     

Alcohol Modulation of Human Normal T-Cell Activation, Maturation, and Migration

We are interested in the characterization of the effects of alcohol on human T-cell activation, maturation, and migration, because this cell population is crucial in the initiation, regulation, and propagation of cellular immunity. We and others have described the effects of both acute and chronic exposure of human immune cells to ethanol (EtOH) in vitro. Herein, we briefly, review these reports and expand this body of literature with the inclusion of new data recently obtained in our laboratory. We confirm the blunting effects of EtOH on the production of interleukin-2 and mitogen proliferative response following T-cell mitogen stimulation, and on the expression of membrane markers of activation. We show that EtOH significantly alters the expression of the CD4 cell-associated marker of activation, CD26. We report the effect of EtOH on the expression of the homing receptor CD62L by CD4⁺ cells, and on their ability to adhere by a CD18-mediated process to a defined cellular substratum. Furthermore, we demonstrate the effects of EtOH and EtOH and 0-endor-phin pretreatment on the activation of CD4⁺ lymphocytes endowed with the homing receptor CD62L.     

Examination of pituitary adenylate cyclase-activating polypeptide in Parkinson’s disease focusing on correlations with motor symptoms

GeroScience - The neuroprotective effects of pituitary adenylate cyclase-activating polypeptide (PACAP) have been shown in numerous in vitro and in vivo models of Parkinson’s disease (PD)...     

Enhanced ferromagnetism of ZnO@Co/Ni hybrid core@shell nanowires grown by electrochemical deposition method

The hybrid structure of ZnO NWs with the presence of different dopants recently has drawn many interests from researchers due to the possibility to integrate multiple functionalities into one single structure. In this article, we investigated the morphology, crystal structure and ferromagnetism of the ZnO@Co/Ni hybrid core@shell NWs prepared by a facile electrochemical deposition method. The results show that a thin layer of Ni and Co coated on the surface of ZnO NWs (confirmed by XRD, EDS, TEM and Raman scattering) can create a significant improvement of ferromagnetic property in such hybrid core@shell NWs. In which, for the coating time of 10, 15, 20 min, the value of M_s is around 0.67, 0.88 and 2.56 emu g⁻¹ for ZnO@Co NWs, and about 0.013, 0.022 and 0.031 emu g⁻¹ for ZnO@Ni NWs, respectively, in comparison with the number of 0.016 emu g⁻¹ for pure ZnO NWs. Interestingly, we also found the temperature dependence of ferromagnetism of such Co/Ni coated ZnO NWs. These results reveal the possibility to employ such hybrid core@shell NWs for many applications, e.g. spin field effect transistors.

Facile electrochemical synthesis of ZnO@Co and ZnO@Ni hybrid core@shell nanowires with enhanced ferromagnetism.     

Amelioration of Neurosensory Structure and Function in Animal and Cellular Models of a Congenital Blindness

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