51,960 research outputs found
Modulation of adrenal catecholamine secretion by in vivo gene transfer and manipulation of G protein-coupled receptor kinase-2 activity
No full textWe recently reported that the upregulation of adrenal G protein-coupled receptor kinase-2 (GRK2) causes enhanced catecholamine (CA) secretion by desensitizing sympatho-inhibitory alpha (2)-adrenergic receptors (alpha (2)ARs) of chromaffin cells, and thereby aggravating heart failure (HF). In this study, we sought to develop an efficient and reproducible in vivo adrenal gene transfer method to determine whether manipulation of adrenal GRK2 levels/activity regulates physiological CA secretion in rats. We specifically investigated two different in vivo gene delivery methods: direct injection into the suprarenal glands, and retrograde delivery through the suprarenal veins. We delivered adenoviral (Ad) vectors containing either GRK2 or an inhibitor of GRK2 activity, the beta ARKct. We found both delivery approaches equally effective at supporting robust (>80% of the whole organ) and adrenal-restricted transgene expression, in the cortical region as well as in the medullar region. Additionally, rats with AdGRK2-infected adrenals exhibit enhanced plasma CA levels when compared with control rats (AdGFP-injected adrenals), whereas plasma CA levels after Ad beta ARKct infection were significantly lower. Finally, in isolated chromaffin cells, alpha (2)ARs of AdGRK2-infected cells failed to inhibit CA secretion whereas Ad beta ARKct-infected cells showed normal alpha (2)AR responsiveness. These results not only indicate that in vivo adrenal gene transfer is an effective way of manipulating adrenal gland signalling, but also identify GRK2 as a critically important molecule involved in CA secretion
Analysis of AAV serotypes 1-9 mediated gene expression and tropism in mice after systemic injection
No full textThis study examines transgene expression and biodistribution of adeno-associated virus (AAV) pseudotyped 1-9 after tail vein (TV) injection in male mice. Using a cytomegalovirus (CMV)-luciferase transgene, the time-course of expression in each animal was tracked throughout the experiment. The animals were imaged at 7, 14, 29, 56, and 100 days after the TV injection. The total number of photons emitted from each animal was recorded, allowing examination of expression level and kinetics for each pseudotyped virus. The bioluminescence imaging revealed three expression levels (i) low-expression group, AAV2, 3, 4, and 5; (ii) moderate-expression group, AAV1, 6, and 8; and (iii) high-expression group, AAV7 and 9. In addition, imaging revealed two classes of kinetics (i) rapid-onset, for AAV1, 6, 7, 8, and 9; and (ii) slow-onset, for AAV2, 3, 4, and 5. We next evaluated protein expression and viral genome copy numbers in dissected tissues. AAV9 had the best viral genome distribution and highest protein levels. The AAV7 protein and genome copy numbers were comparable to those of AAV9 in the liver. Most surprisingly, AAV4 showed the greatest number of genome copies in lung and kidney, and a high copy number in the heart. AAV6 expression was observed in the heart, liver, and skeletal muscle, and the genome distribution corroborated these observations
An adrenal β-arrestin 1-mediated signaling pathway underlies angiotensin II-induced aldosterone production in vitro and in vivo
No full textAldosterone produces a multitude of effects in vivo, including promotion of postmyocardial infarction adverse cardiac remodeling and heart failure progression. It is produced and secreted by the adrenocortical zona glomerulosa (AZG) cells after angiotensin II (AngII) activation of AngII type 1 receptors (AT(1)Rs). Until now, the general consensus for AngII signaling to aldosterone production has been that it proceeds via activation of G(q/11)-proteins, to which the AT(1)R normally couples. Here, we describe a novel signaling pathway underlying this AT(1)R-dependent aldosterone production mediated by beta-arrestin-1 (betaarr1), a universal heptahelical receptor adapter/scaffolding protein. This pathway results in sustained ERK activation and subsequent up-regulation of steroidogenic acute regulatory protein, a steroid transport protein regulating aldosterone biosynthesis in AZG cells. Also, this betaarr1-mediated pathway appears capable of promoting aldosterone turnover independently of G protein activation, because treatment of AZG cells with SII, an AngII analog that induces betaarr, but not G protein coupling to the AT(1)R, recapitulates the effects of AngII on aldosterone production and secretion. In vivo, increased adrenal betaarr1 activity, by means of adrenal-targeted adenoviral-mediated gene delivery of a betaarr1 transgene, resulted in a marked elevation of circulating aldosterone levels in otherwise normal animals, suggesting that this adrenocortical betaarr1-mediated signaling pathway is operative, and promotes aldosterone production and secretion in vivo, as well. Thus, inhibition of adrenal betaarr1 activity on AT(1)Rs might be of therapeutic value in pathological conditions characterized and aggravated by hyperaldosteronism
Comparative cardiac gene delivery of adeno-associated virus serotypes 1-9 reveals that AAV6 mediates the most efficient transduction in mouse heart
No full textCardiac gene transfer is an attractive tool for developing novel heart disease treatments. Adeno-associated viral (AAV) vectors are widely used to mediate transgene expression in animal models and are being evaluated for human gene therapy. However, it is not clear which serotype displays the best cardiac tropism. Therefore, we curried out this study to directly compare AAV serotypes 1-9 heart transduction efficiency after indirect intracoronary injection. AAV-cytomegalovirus immediate early enhancer promoter (CMV)-luciferase serotypes 1-9 were injected in the left ventricular cavity of adult mice, after cross-clamping the ascending aorta and pulmonary artery. An imaging system was used to visualize luciferase expression at 3, 7, 21, 70, and 140 days postinjection. Echocardiography was performed to evaluate cardiac function on day 140. At the end of the study, luciferase enzyme activity and genome copies of the different AAV serotypes were assessed in several tissues and potential AAV immunogenicity was evaluated on heart sections by staining for macrophage and lymphocyte antigens. Among AAV serotypes 1-9, AAV6 showed the best capability of achieving high transduction levels in the myocardium in a tissue-specific manner, whereas the other serotypes had less cardiac transduction and more extracardiac expression, especially in the liver. Importantly, none of the serotypes tested with this marker gene affected cardiac function nor was associated with inflammation
Myocardial adeno-associated virus serotype 6-betaARKct gene therapy improves cardiac function and normalizes the neurohormonal axis in chronic heart failure
No full textMyocardial adeno-associated virus serotype 6-βARKct gene therapy improves cardiac function and normalizes the neurohormonal axis in chronic heart failure
No full textThe upregulation of G protein-coupled receptor kinase 2 in failing myocardium appears to contribute to dysfunctional beta-adrenergic receptor (betaAR) signaling and cardiac function. The peptide betaARKct, which can inhibit the activation of G protein-coupled receptor kinase 2 and improve betaAR signaling, has been shown in transgenic models and short-term gene transfer experiments to rescue heart failure (HF). This study was designed to evaluate long-term betaARKct expression in HF with the use of stable myocardial gene delivery with adeno-associated virus serotype 6 (AAV6)
Management of Unruptured AVMs: The Pendulum Swings
No full textThe ARUBA study is a multi-institutional randomized controlled trial that compared the risk of death and
symptomatic stroke in patients with unruptured AVMs.
Patients were randomized in a 1:1 ratio to medical management versus interventional therapy plus medical management. The intervention given to the patient (surgical removal,
embolization, stereotactic radiosurgery [SRS], or a combination of these) was left to the discretion of the individual
practitioners. The study was closed to accrual early when it
reached prespecified stopping rules, with results suggesting
the superiority of the medical management group. At that
time, 114 patients were assigned to interventional therapy and
109 to medical management. The risk of death or stroke was
significantly lower in the medical management group than in
the interventional group (hazard ratio, 0.27; P < .0001)
The IMPACT of Molecular Grading of Gliomas on Contemporary Clinical Practice
No full textMore recently, significant advances have been made in the understanding of the molecular pathogenesis of gliomas. For example, isocitrate dehydrogenase (IDH) mutation is a defining event in glioma development, appearing early in gliomagenesis and giving rise to gliomas with distinct behavior. Mutations in IDH, a rate-limiting enzyme in the Krebs cycle, likely affect metabolic activity and genetic expression
Development of composite calibration standard for quantitative NDE by ultrasound and thermography
No full textInspection of aircraft components for damage utilizing ultrasonic Non-Destructive Evaluation (NDE) is a time intensive endeavor. Additional time spent during aircraft inspections translates to added cost to the company performing them, and as such, reducing this expenditure is of great importance. There is also great variance in the calibration samples from one entity to another due to a lack of a common calibration set. By characterizing damage types, we can condense the required calibration sets and reduce the time required to perform calibration while also providing procedures for the fabrication of these standard sets. We present here our effort to fabricate composite samples with known defects and quantify the size and location of defects, such as delaminations, and impact damage. Ultrasonic and Thermographic images are digitally enhanced to accurately measure the damage size. Ultrasonic NDE is compared with thermography.This proceeding may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.
This proceeding appeared in Dayal, Vinay, Zach G. Benedict, Nishtha Bhatnagar, and Adam G. Harper. "Development of composite calibration standard for quantitative NDE by ultrasound and thermography." In AIP Conference Proceedings, vol. 1949, no. 1, p. 060006. AIP Publishing LLC, 2018, and may be found at
DOI: 10.1063/1.5031552.
Copyright 2018 The Author(s).
Posted with permission
Stereotactic Radiosurgery for Resected Brain Metastases: New Evidence Supports a Practice Shift, but Questions Remain
No full textBrain metastases are a common and devastating complication of cancer. Surgical resection of brain metastases remains an important treatment modality, especially for larger lesions with symptomatic mass effect. However, recurrence in the surgical bed occurs in approximately 60% of cases following resection alone
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