Focal adhesion kinase signaling determines the fate of lung epithelial cells in response to TGF-ß.

Alveolar epithelial cell (AEC) injury and apoptosis are prominent pathological features of idiopathic pulmonary fibrosis (IPF). There is evidence of AEC plasticity in lung injury repair response and in IPF. In this report, we explore the role of focal adhesion kinase (FAK) signaling in determining the fate of lung epithelial cells in response to transforming growth factor-ß1 (TGF-ß1). Rat type II alveolar epithelial cells (RLE-6TN) were treated with or without TGF-ß1, and the expressions of mesenchymal markers, phenotype, and function were analyzed. Pharmacological protein kinase inhibitors were utilized to screen for SMAD-dependent and -independent pathways. SMAD and FAK signaling was analyzed using siRNA knockdown, inhibitors, and expression of a mutant construct of FAK. Apoptosis was measured using cleaved caspase-3 and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. TGF-ß1 induced the acquisition of mesenchymal markers, including α-smooth muscle actin, in RLE-6TN cells and enhanced the contraction of three-dimensional collagen gels. This phenotypical transition or plasticity, epithelial-myofibroblast plasticity (EMP), is dependent on SMAD3 and FAK signaling. FAK activation was found to be dependent on ALK5/SMAD3 signaling. We observed that TGF-ß1 induces both EMP and apoptosis in the same cell culture system but not in the same cell. While blockade of SMAD signaling inhibited EMP, it had a minimal effect on apoptosis; in contrast, inhibition of FAK signaling markedly shifted to an apoptotic fate. The data support that FAK activation determines whether AECs undergo EMP vs. apoptosis in response to TGF-ß1 stimulation. TGF-ß1-induced EMP is FAK- dependent, whereas TGF-ß1-induced apoptosis is favored when FAK signaling is inhibited.

Clinical signs of nitrous oxide use: case report and review of the literature.

Nitrous oxide is used medically as an anesthetic agent; in the food industry as a propellant for condiments; and recreationally for its euphoric and dissociative effects. We report three cases of nitrous oxide misuse causing severe, symptomatic cobalamin (vitamin B12) deficiency in which signs of nitrous oxide use per se, as well as signs of toxicity, were observed, including characteristic palmar calluses over the metacarpal heads, and frostbite. These signs may assist clinicians in the recognition of nitrous oxide use and the timely diagnosis of nitrous oxide toxicity.

Relationship between breast-feeding and adiposity in infants and pre-school children.

OBJECTIVES: We aimed to establish associations of duration of breast-feeding with mean BMI and waist circumference, as well as the likelihood of being overweight/obese, during early childhood. DESIGN: Cross-sectional, population-based study. Height, weight and waist circumference were measured and BMI calculated. Interviewer-administered questionnaire determined whether the child was ever breast-fed and the duration of breast-feeding. SETTING: Sydney, Australia. SUBJECTS: Infants and pre-school children (n 2092) aged 1-6 years were examined in the Sydney Paediatric Eye Disease Study during 2007-2009. RESULTS: Of the children aged 1-6 years, 1270 had been breast-fed compared with 822 who were never breast-fed. After multivariable adjustment, 1-6-year-old children who were ever breast-fed compared with those who were not had significantly lower BMI, 16·7 (se 0·1) kg/m2 v. 17·1 (se 0·2) kg/m2 (P = 0·01). Decreasing BMI was associated with increasing duration of breast-feeding (P trend = 0·002). After multivariable adjustment, each month increase in breast-feeding was associated with an average BMI decrease of 0·04 kg/m2 (P = 0·002) and 0·03 kg/m2 (P = 0·03) among children aged 1-2 years and 3-4 years, respectively. In 1-2-year-old children, each month increase in breast-feeding duration was associated with a 0·06 cm decrease in waist circumference (P = 0·04). Significant associations were not observed among 5-6-year-old children. Children who were ever breast-fed v. those never breast-fed were less likely to be overweight/obese (multivariable-adjusted OR = 0·54; 95 % CI 0·36, 0·83). CONCLUSIONS: We demonstrated a modest influence of breast-feeding on children's BMI during early childhood, particularly among those aged less than 5 years.

Hydrogen peroxide is a diffusible paracrine signal for the induction of epithelial cell death by activated myofibroblasts.

Cell-cell signaling roles for reactive oxygen species (ROS) generated in response to growth factors/cytokines in nonphagocytic cells are not well defined. In this study, we show that fibroblasts isolated from lungs of patients with idiopathic pulmonary fibrosis (IPF) generate extracellular hydrogen peroxide (H2O2) in response to the multifunctional cytokine, transforming growth factor-beta1 (TGF-beta1). In contrast, TGF-beta1 stimulation of small airway epithelial cells (SAECs) does not result in detectable levels of extracellular H2O2. IPF fibroblasts independently stimulated with TGF-beta1 induce loss of viability and death of overlying SAECs when cocultured in a compartmentalized Transwell system. These effects on SAECs are inhibited by the addition of catalase to the coculture system or by the selective enzymatic blockade of H2O2 production by IPF fibroblasts. IPF fibroblasts heterogeneously express alpha-smooth muscle actin stress fibers, a marker of myofibroblast differentiation. Cellular localization of H2O2 by a fluorescent-labeling strategy demonstrated that extracellular secretion of H2O2 is specific to the myofibroblast phenotype. Thus, myofibroblast secretion of H2O2 functions as a diffusible death signal for lung epithelial cells. This novel mechanism for intercellular ROS signaling may be important in physiological/pathophysiological processes characterized by regenerating epithelial cells and activated myofibroblasts.

A Simplified Protocol for the Treatment of Alcohol Withdrawal.

OBJECTIVES: The aim of the study was to evaluate a novel simplified tool for symptom-triggered treatment of alcohol withdrawal. METHODS: This retrospective cohort study involved inpatients in a county hospital with an International Classification of Diseases, Ninth Revision, Clinical Modification discharge diagnosis of alcohol withdrawal syndrome (AWS) or delirium tremens between January 1, 2007 and December 31, 2008. The study used the Highland Alcohol Withdrawal Protocol (HAWP)-a simplified derivative of the Revised Clinical Institute Withdrawal Assessment for Alcohol. Multivariable regression analysis was performed to compare severity of withdrawal to hospital length of stay, total dose of sedative given, and risk of complications. RESULTS: The study identified 442 patients with a primary diagnosis of AWS or delirium tremens, and those with another primary medical diagnosis complicated by alcohol withdrawal. After adjusting for demographic variables, each one-point increase in the initial and maximum HAWP scores correlated with an increase in the hospital length of stay of 0.3 days [95% confidence interval (95% CI), 0.17 to 0.43 days] and 0.45 days (95% CI, 0.32-0.57 days), and a 15.8 mg (95% CI, 6.6-25.1 mg) and 19.8 mg (95% CI, 11.1-28.5 mg) increase in the total dose of lorazepam given, respectively. The complication rate of seizures, intubations, pneumonia, and death was 13.1%, 12.9%, 6.1% and 0.9%, respectively; a composite endpoint of these outcomes also correlated with initial and maximum HAWP scores (odds ratio 1.09, 95% CI, 1.03%-1.14%). CONCLUSIONS: The HAWP correlates with medication received and complications, and as such appears to give an indication of AWS severity. It is feasible and shorter than prior scales, and merits further study to confirm its effectiveness as part of symptom-triggered protocols to manage alcohol withdrawal in the hospital.