2,243 publications from this institution
α-Klotho (α-KL), a protein with antiaging properties, regulates phosphate, calcium, and bone metabolism, induces resistance to oxidative stress, and may participate in insulin signaling. The role of α-KL in neonates, known to be prone to metabolic disturbances and oxidative stress, is not known. The aim of this study was to evaluate circulating soluble α-KL concentrations in preterm and full-term neonates and unravel possible correlations with growth, metabolism, and indices of oxidative stress.Prospective study.Plasma-soluble α-KL levels were determined by specific ELISA in 50 healthy neonates (25 preterm, mean (s.d.) gestational age (GA) 33.7 (1.1) weeks, and 25 full-term infants) at days 14 and 28 of life. Associations of α-KL with anthropometric, metabolic parameters, and indices of oxidative stress were examined.α-KL levels were significantly higher in full-term than in preterm infants at both days 14 (1099 (480) pg/ml vs 884 (239) pg/ml respectively; P<0.05) and 28 (1277 (444) pg/ml vs 983 (264) pg/ml respectively; P<0.01). In both preterm and full-term infants, α-KL levels increased significantly from day 14 to 28 of life (P<0.001). Circulating α-KL concentrations correlated with GA (β=0.32, P=0.001), body weight (β=0.34, P=0.001), body length (β=0.33, P=0.001), 1,25-dihydroxy-vitamin D level (β=0.24, P<0.05), and malondialdehyde level (β=0.20, P<0.05) but not with glucose, insulin, or homeostasis model assessment index of insulin resistance values.Soluble α-KL levels rise as GA and postnatal age advance in neonates and may have an impact on vitamin D metabolism and oxidative stress. Whether α-KL may have a role in the regulation of infants' growth should be further studied.
Memphis Lung Research Program, Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine Memphis, TN First Department of Pediatrics Athens University Medical School Athens, Greece The authors have no financial interests to disclose.
The parametric representation of rocking fragilities is statistically investigated. Initially, the potential normalization of the rocking parameters to reduce the problem's dimensionality is tackled by undertaking comparisons both on a single‐record and a sample‐of‐records basis. It is found that the slenderness angle can be normalized out when probabilistically considering the rocking response of simple rocking blocks with the same semi‐diagonal length. Then, the robustness of the lognormal distribution for characterizing the rocking motion is investigated. Sets of pulse‐like and ordinary ground motions are employed to test the lognormal fit for the full range of rocking response when the peak ground acceleration or the peak ground velocity are employed as intensity measures. In both cases, the lognormal distribution offers an adequate, but often imperfect, baseline model of the rocking fragility curves. Instead, a shifted lognormal that accounts for the absence of response below the rocking initiation intensity is an enhanced solution that can form the basis for offering simplified response model surrogates.
No abstract is provided for this article.
<h3>Objective.</h3> —This article defines stress and related concepts and reviews their historical development. The notion of a stress system as the effector of the stress syndrome is suggested, and its physiologic and pathophysiologic manifestations are described. A new perspective on human disease states associated with dysregulation of the stress system is provided. <h3>Data Sources.</h3> —Published original articles from human and animal studies and selected reviews. Literature was surveyed utilizing MEDLINE and the<i>Index Medicus</i>. <h3>Study Selection.</h3> —Original articles from the basic science and human literature consisted entirely of controlled studies based on verified methodologies and, with the exception of the most recent studies, replicated by more than one laboratory. Many of the basic science and clinical studies had been conducted in our own laboratories and clinical research units. Reviews cited were written by acknowledged leaders in the fields of neurobiology, endocrinology, and behavior. <h3>Data Extraction.</h3> —Independent extraction and cross-referencing by the authors. <h3>Data Synthesis.</h3> —Stress and related concepts can be traced as far back as written science and medicine. The stress system coordinates the generalized stress response, which takes place when a stressor of any kind exceeds a threshold. The main components of the stress system are the corticotropin-releasing hormone and locus ceruleus-norepinephrine/autonomic systems and their peripheral effectors, the pituitary-adrenal axis, and the limbs of the autonomic system. Activation of the stress system leads to behavioral and peripheral changes that improve the ability of the organism to adjust homeostasis and increase its chances for survival. There has been an exponential increase in knowledge regarding the interactions among the components of the stress system and between the stress system and other brain elements involved in the regulation of emotion, cognitive function, and behavior, as well as with the axes responsible for reproduction, growth, and immunity. This new knowledge has allowed association of stress system dysfunction, characterized by sustained hyperactivity and/or hypoactivity, to various pathophysiologic states that cut across the traditional boundaries of medical disciplines. These include a range of psychiatric, endocrine, and inflammatory disorders and/or susceptibility to such disorders. <h3>Conclusions.</h3> —We hope that knowledge from apparently disparate fields of science and medicine integrated into a working theoretical framework will allow generation and testing of new hypotheses on the pathophysiology and diagnosis of, and therapy for, a variety of human illnesses reflecting systematic alterations in the principal effectors of the generalized stress response. We predict that pharmacologic agents capable of altering the central apparatus that governs the stress response will be useful in the treatment of many of these illnesses. (<i>JAMA</i>. 1992;267:1244-1252)