1154insTC is not a rare CFTR mutation.
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Biomedical subjects
Publications and source records attributed to James Cook.
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BACKGROUND: Some current pacing systems can automatically detect and record atrial tachyarrhythmias that may be asymptomatic. We prospectively studied a 312-patient (pt) subgroup of MOST (MOde Selection Trial), a 2010-patient, 6-year randomized trial of DDDR versus VVIR pacing in sinus node dysfunction (SND). The purpose of the study was to correlate atrial high rate events (AHREs) detected by pacemaker diagnostics with clinical outcomes. METHODS AND RESULTS: Pacemakers were programmed to log an AHRE when the atrial rate was >220 bpm for 10 consecutive beats. Analysis was confined to patients with at least 1 AHRE duration exceeding 5 minutes. The 312 patients were median age 74 years, 55% female, and 60% had a history of SVT. 160 of 312 (51.3%) patients enrolled had at least 1 AHRE >5 minutes duration over median follow-up of 27 months. Cox proportional hazards analysis assessed the relationship of AHREs with clinical events, adjusting for prognostic variables and baseline covariates. The presence of any AHRE was an independent predictor of the following: total mortality (hazard ratio AHRE versus no AHRE and 95% confidence intervals=2.48 [1.25, 4.91], P=0.0092); death or nonfatal stroke (2.79 [1.51, 5.15], P=0.0011); and atrial fibrillation (5.93 [2.88, 12.2], P=0.0001). There was no significant effect of pacing mode on the presence or absence of AHREs. CONCLUSIONS: AHRE detected by pacemakers in patients with SND identify patients that are more than twice as likely to die or have a stroke, and 6 times as likely to develop atrial fibrillation as similar patients without AHRE.
Bacterial products, such as lipopolysaccharide (LPS) or heat-killed Escherichia coli (EC), and heat-killed Staphylococcus aureus (SA) are potent activators of macrophages (MØ). When stimulated by these bacterial components, MØ produce inflammatory mediators, such as nitric oxide (NO) and thromboxane (Tx) B(2). Bacterial mediator production is preceded by the activation of various signal transduction pathways. Agonists that activate the peroxisome proliferator-activated receptor-gamma (PPARgamma) have been shown to block MØ mediator production by LPS and other stimuli. However, very little is known about the effects of PPARgamma agonists on SA- or EC-induced MØ activation. Therefore, we investigated whether the PPARgamma agonists 15-deoxy-Delta12,14 prostaglandin J(2) (15-PGJ(2)) and troglitazone block LPS-, EC-, or SA-induced mediator production. Rat peritoneal MØ were stimulated with LPS, EC, or SA (10 microg/mL) with or without increasing concentrations (0.1 to 10 microM) of each PPARgamma agonist and NO and TxB(2) production were measured. 15-PGJ(2) decreased LPS-, EC-, and SA-induced NO and TxB(2) production. However, troglitazone only inhibited the production of TxB(2) by each stimuli. In parallel studies, the effects of PPARgamma agonists on signaling pathways were evaluated. Rat peritoneal MØ were pretreated for 1 h with 15-PGJ(2) or troglitazone (1 or 10 microM) and then stimulated for 40 min with LPS, EC, or SA (10 microg/mL). Western blot analysis demonstrated that 15-PGJ(2) significantly inhibited LPS-, EC-, and SA-induced ERK (1/2) activation and blocked IkappaBalpha degradation. Troglitazone had no significant effect on either signaling protein. The data demonstrate that although both 15-PGJ(2) and troglitazone are considered PPARgamma agonists, they differentially affect mediator production and cell signaling events. PPARgamma-independent effects of 15-PGJ(2) may contribute to its more potent anti-inflammatory effects compared with troglitazone.
RATIONALE: Delineation of the receptor mechanisms underlying the behavioral effects of benzodiazepines should allow for the development of drugs with improved clinical utility and reduced side effects. OBJECTIVES. The purpose of the present study was to investigate the role of GABAA/alpha1 receptors in the sedative and motor-impairing effects of benzodiazepines. METHODS: Squirrel monkeys were tested with the GABAA/alpha1-preferring agonist zolpidem and the nonselective benzodiazepine agonist triazolam alone and in combination with the GABAA/alpha1-preferring antagonist beta-CCt and the nonselective benzodiazepine antagonist flumazenil. During 30-min experimental sessions, all occurrences of normal behaviors like locomotion, environment- and self-directed behaviors, as well as side effects such as ataxia, rest and procumbent postures were scored. RESULTS: Zolpidem and triazolam produced dose-dependent reductions in locomotion and environment-directed behavior and increased ataxia and procumbent posture. Triazolam, but not zolpidem, also engendered species-typical rest posture at some doses. Flumazenil antagonized all of the behavioral effects of zolpidem and triazolam, whereas beta-CCt antagonized only zolpidem- and triazolam-induced ataxia. CONCLUSIONS: GABAA/alpha1 receptor mechanisms appear to play a key role in the ataxic effects of benzodiazepine agonists in squirrel monkeys, similar to recent results with transgenic mice. In contrast to the findings of these recent studies, GABAA mechanisms other than or in addition to those mediated at the alpha1 subunit may play a more important role in the sedative/hypnotic effects of benzodiazepines in squirrel monkeys.
TNF-alpha is a mediator of lethality in experimental infections by group B streptococcus (GBS), an important human pathogen. Little is known of signal transduction pathways involved in GBS-induced TNF-alpha production. Here we investigate the role of mitogen-activated protein kinases (MAPKs) and NF-kappa B in TNF-alpha production by human monocytes stimulated with GBS or LPS, used as a positive control. Western blot analysis of cell lysates indicates that extracellular signal-regulated kinase 1/2 (ERK 1/2), p38, and c-Jun N-terminal kinase MAPKs, as well as I kappa B alpha, became phosphorylated, and hence activated, in both LPS- and GBS-stimulated monocytes. The kinetics of these phosphorylation events, as well as those of TNF-alpha production, were delayed by 30-60 min in GBS-stimulated, relative to LPS-stimulated, monocytes. Selective inhibitors of ERK 1/2 (PD98059 or U0126), p38 (SB203580), or NF-kappa B (caffeic acid phenetyl ester (CAPE)) could all significantly reduce TNF-alpha production, although none of the inhibitors used alone was able to completely prevent TNF-alpha release. However, this was completely blocked by combinations of the inhibitors, including PD98059-SB203580, PD98059-CAPE, or SB203580-CAPE combinations, in both LPS- and GBS-stimulated monocytes. In conclusion, our data indicate that the simultaneous activation of multiple pathways, including NF-kappa B, ERK 1/2, and p38 MAPKs, is required to induce maximal TNF-alpha production. Accordingly, in septic shock caused by either GBS or Gram-negative bacteria, complete inhibition of TNF-alpha release may require treatment with drugs or drug combinations capable of inhibiting multiple activation pathways.
This article reports a new, transient, but identical electrocardiogram presentation in 2 patients at 2 different institutions. While its mechanism is uncertain, analysis by exclusion suggests that a diffusely prolonged but nonhomogenous myocardial refractoriness may have altered both QRS morphology and amplitude and also may have resulted in periods of 2:1 AV block.