The Caenorhabditis elegans IMPAS gene, imp-2, is essential for development and is functionally distinct from related presenilins

Presenilins (PSs) are required for Notch signaling in the development of vertebrates and invertebrates. Mutations in human PS1 and PS2 homologs are a cause of familial Alzheimer's disease (AD). The function of the recently identified ancient family of IMPAS proteins (IMP/SPP/PSH) homologous to PSs is not yet known. We show here that, unlike PSs, IMPs (orthologous C. elegans Ce-imp-2 and human hIMP1/SPP) do not promote Notch (C. elegans lin-12,glp-1) proteolysis or signaling. The knock-down of Ce-imp-2 leads to embryonic death and an abnormal molting phenotype in Caenorhabditis elegans. The molting defect induced by Ce-imp-2 deficiency was mimicked by depleting cholesterol or disrupting Ce-lrp-1 and suppressed, in part, by expression of the Ce-lrp-1 derivate. C. elegans lrp-1 is a homolog of mammalian megalin, lipoprotein receptor-related protein (LRP) receptors essential for cholesterol and lipoprotein endocytosis and signaling. These data suggest that IMPs are functionally distinct from related PSs and implicate IMPs as critical regulators of development that may potentially interact with the lipid-lipoprotein receptor-mediated pathway.     

Three‐months optical coherence tomography analysis of a biodegradable polymer,sirolimus‐eluting stent

Objective

We aimed to assess early neointimal healing by optical coherence tomography (OCT) 3 months after implantation of the ultrathin Orsiro® sirolimus‐eluting stent with biodegradable polymer.

Background

New generations of drug‐eluting stents with biodegradable polymer have been developed to avoid the continued vascular irritation of durable polymers.

Methods

In this prospective, open‐label study, 34 patients received an Orsiro® sirolimus‐eluting stent with biodegradable polymer. In a subgroup of patients (n = 15), the intervention was performed under OCT guidance. All patients underwent OCT‐examination at three months. The primary endpoint was 3‐month neointimal healing (NIH) score, calculated by weighing the presence of filling defects, malapposed and uncovered struts. Secondary endpoint was maturity of tissue coverage at 3 months.

Results

At 3 months, NIH score was 13.7 (5.4‐22), covered struts per lesion were 90% (84‐97%), malapposed struts were 2.7% (0.8‐5.4%) and rate of mature tissue coverage was 47% (42‐53%). No target lesion failure occurred up to 12 months. Patients with OCT‐guided stent implantation demonstrated a trend toward earlier stent healing as demonstrated by superior NIH scores (angio guided: 17.6% [8.8‐26.4]; OCT‐guided: 9.8% [4.0‐15.5]; mean difference ?8, [95%CI: ?18.7‐2.9], P = 0.123). This group had significantly more covered struts per lesion (angio‐guided: 86% [82‐90]; 95% [92‐99]; mean difference 9% [95%CI: 3‐15], P = 0.001).

Conclusion

The Orsiro® sirolimus‐eluting stent with biodegradable polymer shows early vascular healing with a high rate of strut coverage at 3‐month follow‐up. OCT guided stent implantation had a positive impact on early vascular healing.

     

Ionic mechanisms underlying region-specific remodeling of rabbit atrial action potentials caused by intermittent burst stimulation.

BACKGROUND: Pulmonary veins (PVs) and the coronary sinus (CS) play pivotal roles in triggering some episodes of atrial fibrillation. In isolated rabbit right or left atrial preparations, a 3-hour intermittent burst pacing protocol shortens action potential duration (APD) in CS and PV, but not in sinus node (SN) and left Bachmann bundle (BB) regions. OBJECTIVE: The purpose of this study was to use patch clamp techniques to study the rapidly inactivating (I(to)) and sustained (I(sus)) K(+) currents as well as Ca(2+) currents (I(Ca)) in cells dispersed from intermittent burst pacing and sham PV, BB, CS, and SN regions to determine whether changes in these currents contributed to APD shortening. METHODS: Real-time polymerase chain reaction was performed for transient outward K(+) and Ca(2+) channel subunit mRNAs to determine if intermittent burst pacing affected expression levels. RESULTS: I(to) densities were unaffected by intermittent burst pacing in PV and Bachmann bundle cells. mRNA levels of K(V)4.3, K(V)4.2, K(V)1.4, and KChIP2 subunits of I(to) in both regions were stable. In CS cells, I(to) densities in intermittent burst pacing were greater than in sham (P <.05), but there were no parallel mRNA changes. I(Ca) density of PV cells was reduced from 14.27 +/- 2.08 pA/pF (at -5 mV) in sham to 7.52 +/- 1.65 pA/pF in intermittent burst pacing PV cells (P <.05) due to a significant shift in voltage dependence of activation. These results were seen in the absence of mRNA changes in alpha(1C) and alpha(1D) Ca(2+) channel subunits. In contrast, intermittent burst pacing had no effect on Ca(2+) current densities and kinetics of CS cells, but decreased alpha(1)C and alpha(1)D mRNA levels. CONCLUSION: There is region-specific remodeling of I(to) and I(Ca) by intermittent burst pacing protocols in rabbit atrium. Increased I(to) in CS cells could account for the APD shortening observed with intermittent burst pacing, whereas an intermittent burst pacing-induced shift in voltage dependence of activation may contribute to APD shortening in PV cells.     

Half-dose gadobenate dimeglumine versus standard-dose gadodiamide in dynamic magnetic resonance imaging of non-cirrhotic livers: a retrospective intra-individual crossover comparison

Purpose

The purpose of this study was to compare enhancement characteristics of half-dose gadobenate dimeglumine (0.05 mmol kg^?1) with standard-dose gadodiamide (0.10 mmol kg^?1), in the assessment of hepatic vessels and lesions, using retrospective intra-individual crossover comparison methodology.

Methods

Ethics committee approval was obtained. From 2004 to 2012, 21 patients underwent MRI examination with both standard-dose gadodiamide and half-dose gadobenate dimeglumine, using the same liver MRI protocol at 1.5 T. Eighteen patients whose scans showed no artifacts were selected. Quality of liver lesion [12 hemangiomas, 7 focal nodular hyperplasias (FNHs)] and liver vessel enhancement, and the global diagnostic quality of studies were ranked on a scale of 1–4 by two independent radiologists. Contrast-to-noise ratio (CNR) and % enhancement of liver vessels and lesions were calculated based on region of interest, signal intensity, and noise standard deviation measurements performed at 0, 20 s, 1, 3, and 5 min post-contrast injection. Qualitative and quantitative results were compared using the paired Wilcoxon signed rank and Student’s t-tests, respectively.

Results

No qualitative differences were noted in enhancement of liver vessels, hemangiomas, and FNHs. There was no statistically significant difference between the global diagnostic qualities of scans performed with the two contrast agents. Quantitatively, liver vessels and hemangiomas did not demonstrate statistically significant differences in contrast enhancement. At 20 s, FNHs achieved higher CNR (P = 0.02) with gadodiamide.

Conclusion

Half-dose gadobenate dimeglumine results in similar contrast enhancement compared to standard-dose gadodiamide in assessment of liver vessels, hemangiomas, and FNHs, and is a reasonable alternative to standard doses of extracellular agents in dynamic liver MRI.     

Nondisclosure of HIV Infection to Sex Partners and Alcohol’s Role: A Russian Experience

Nondisclosure of one’s HIV infection to sexual partners obviates safer sex negotiations and thus jeopardizes HIV transmission prevention. The role of alcohol use in the disclosure decision process is largely unexplored. This study assessed the association between alcohol use and recent nondisclosure of HIV serostatus to sex partners by HIV-infected risky drinkers in St. Petersburg, Russia. Approximately half (317/605; 52.4 %) reported not having disclosed their HIV serostatus to all partners since awareness of infection. Using three separate GEE logistic regression models, we found no significant association between alcohol dependence, risky alcohol use (past 30 days), or alcohol use at time of sex (past 30 days) with recent (past 3 months) nondisclosure (AOR [95 % CI] 0.81 [0.55, 1.20], 1.31 [0.79, 2.17], 0.75 [0.54, 1.05], respectively). Alcohol use at time of sex was associated with decreased odds of recent nondisclosure among seroconcordant partners and among casual partners. Factors associated with nondisclosure were relationship with a casual partner, a serodiscordant partner, multiple sex partners, awareness of HIV diagnosis less than 1 year, and a lifetime history of sexually transmitted disease. Nondisclosure of HIV status to sex partners is common among HIV-infected Russians, however alcohol does not appear to be a predictor of recent disclosure.     

Thoracic Epidural Analgesia Augments Ileal Mucosal Capillary Perfusion and Improves Survival in Severe Acute Pancreatitis in Rats

Background: Acute pancreatitis has been linked to intestinal barrier dysfunction and systemic inflammatory response with high mortality. Thoracic epidural analgesia improves intestinal perfusion. The authors hypothesized that thoracic epidural analgesia influences microcirculation injury, inflammatory response, and outcome of acute pancreatitis in rats.

Methods: Control groups underwent a sham procedure or untreated pancreatitis induced by intraductal taurocholate injection. In the treatment groups, epidural analgesia was commenced immediately or after a 7-h delay. Fifteen hours after injury, the ileal mucosal perfusion was assessed by intravital microscopy. Thereby, the intercapillary area between all perfused capillaries and between continuously perfused capillaries only was used to differentially quantify total and continuous capillary mucosal perfusion. Villus blood flow and serum levels of amylase, lactate, and interleukin 6 were determined, and pancreatic injury was scored histologically. Seven-day survival was recorded in an additional 30 rats undergoing untreated pancreatitis or pancreatitis with epidural analgesia.

Results: In untreated pancreatitis, decreased total capillary perfusion increased the total intercapillary area by 24%. Furthermore, loss of continuous perfusion increased continuous intercapillary area to 228%. After immediate and delayed epidural analgesia, continuous perfusion was restored (P < 0.05). Blood flow decreased 50% in untreated pancreatitis but was preserved by epidural analgesia (P < 0.05). Biochemical and histologic signs of pancreatitis were not affected by epidural analgesia. Lactate and interleukin-6 levels increased in untreated pancreatitis, which was prevented in the treatment groups (P < 0.05). Epidural analgesia increased 7-day survival from 33% to 73% (P < 0.05).