378 research outputs found
Prevalence of Abnormal Systemic Hemodynamics in Veterans with and without Spinal Cord Injury
Advances in the clinical management of patients with acute and chronic spinal cord injury (SCI) have contributed to extended life expectancies; however longevity in those with SCI remains below that of the general population.(1) Reduced longevity in the SCI population has been attributed to increased incidence of age-associated chronic illnesses,(2) premature cardiovascular aging,(3) and increased prevalence of heart disease, stroke (4) and diabetes mellitus, (5) compared to the general population. In fact, cardiovascular disease (CVD) is now a leading cause of morbidity and mortality in the SCI population, which may be amplified due to increased risk factors such as inactivity, chronic inflammation, and impairment in autonomic cardiovascular control.(6)
The American Spinal Injury Association (ASIA) impairment scale (AIS) is used to document remaining motor and sensory function following SCI; (7, 8) however, the degree of autonomic nervous system impairment is not considered within this classification schema.(9, 10) That said, impaired autonomic control of the cardiovascular system after SCI results in measurable changes in heart rate (HR) and blood pressure (BP) that loosely reflect the level and completeness of SCI documented using the AIS classification, (11, 12) but may also reflect orthostatic positioning.(6, 12, 13) The impact of these changes in HR and BP on cardiovascular health and longevity is not fully appreciated in the SCI population; however, prior to identifying the consequences of these cardiovascular abnormalities, prevalence rates of HR and BP values which fall outside the expected normal range should be documented.
The International Standards to Document Autonomic Function (post-SCI) initially established guidelines for the assessment of HR and BP abnormalities in 2009, (10) which was updated in 2012, but the thresholds remained consistent. (14) Specifically, bradycardia is defined as a HR ≤ 60 beats/minute (bpm) and tachycardia as a HR ≥ 100 bpm. (14) Hypotension is defined as a systolic BP (SBP) ≤ 90 mmHg and a diastolic BP (DBP) ≤ 60 mmHg; hypertension is SBP ≥ 140 and/or DBP ≥ 90 mmHg. (14) While these definitions comply with standards established in the non-SCI population, due to decentralized cardiovascular control, they may not be appropriate for use in the SCI population. In addition, relatively recent evidence has emerged which associates adverse outcomes in the general population using other HR (15, 16) and BP (17-21) thresholds. Beyond the clinical consequences of alterations in HR and BP, persons with SCI may experience loss of independence and life quality related to the inability to adequately maintain cardiovascular homeostasis; however, until we gain a better understanding of the prevalence of these abnormalities, the development and testing of effective treatment strategies will not be a priority.
Therefore, the goal of this investigation was to assess HR and BP in veterans with (SCI) and without SCI (non SCI). Similar to a recent report, (6) we hypothesized that level of SCI (i.e., the higher the lesion level the greater the prevalence of abnormal HR and BP recordings) and orthostatic positioning (i.e., increased prevalence of abnormal HR and BP recordings in the seated versus the supine position) would influence the prevalence of HR and BP abnormalities. In addition, we hypothesized that the prevalence of comorbid cardiovascular medical conditions, current smoking status, age and use of prescription anti-hypertensive (anti-HTN) medications would influence the prevalence of HR and BP abnormalities in veterans with and without SCI
Cell-Cell Interactions and the Regulation of Testis Function
Regulatory interactions have been shown to occur between all the testicular cell types considered. The paracrine factors mediating these interactions generally influence either cellular growth or differentiation. The regulation of cellular growth is essential in the developing testis and is required for the maintenance of spermatogenesis in the adult testis. The rapid rate of germinal cell proliferation and the continuous but slowed growth of the peritubular cells and Leydig cells requires the presence of specific growth factors in the adult. Therefore, cell-cell interactions have evolved that involve growth factors such as IGF, TGF-alpha, TGF-beta and NGF. Other growth factors such as FGF or less characterized components like the seminiferous growth factor (SGF) also may be involved in the paracrine regulation of testis cell growth. An alternate cellular parameter to cell growth to consider is the regulation of cellular function and differentiation. A number of endocrine agents and locally produced paracrine factors have been shown to control and maintain testis cell function and differentiation. Cell-cell interactions mediated by factors such as androgens, POMC peptides, and PModS are all primarily directed at the regulation of cellular differentiation. Therefore, the agents which mediate cell-cell interactions in the testis can generally be categorized into factors that regulate cell growth or those which influence cellular differentiation. The specific cell-cell interactions identified will likely be the first of a large number of cellular interactions yet to be investigated. Although a number of potentially important cell-cell interactions have been identified, future research will require the elucidation of the in vivo physiological significance of these interactions. The existence of different cell types and potential cell-cell interactions in a tissue implies that the actions of an endocrine agent on a tissue will not simply involve a single hormone and single cell. The endocrine regulation of testis function will have effects on cell-cell interactions and be affected by local cell-cell interactions. The ability of LH to influence Leydig cell androgen production promotes a cascade of interactions mediated through several cell types to maintain the process of spermatogenesis. FSH actions on Sertoli cells also promote cell-cell interactions that influence germinal cell development, peritubular myoid cell differentiation and Leydig cell function. Therefore, elucidation of the endocrine regulation of testis function requires an understanding of the local cell-cell interactions in the testis
Modulation of Cyclic AMP Levels in Fallopian Tube Cells by Natural and Environmental Estrogens
Autocrine/paracrine factors generated in response to 17β-estradiol (E2) within the fallopian tube (FT) facilitate fertilization and early embryo development for implantation. Since cyclic AMP (cAMP) plays a key role in reproduction, regulation of its synthesis by E2 may be of biological/pathophysiological relevance. Herein, we investigated whether cAMP production in FT cells (FTCs) is regulated by E2 and environmental estrogens (EE’s; xenoestrogens and phytoestrogens). Under basal conditions, low levels of extracellular cAMP were detectable in bovine FTCs (epithelial cells and fibroblasts; 1:1 ratio). Treatment of FTCs with forskolin (AC; adenylyl cyclase activator), isoproterenol (β-adrenoceptor agonist) and IBMX (phosphodiesterase (PDE) inhibitor) dramatically (>10 fold) increased cAMP; whereas LRE1 (sAC; soluble AC inhibitor) and 2’,5’-dideoxyadenosine (DDA; transmembrane AC (tmAC)) inhibitor decreased cAMP. Comparable changes in basal and stimulated intracellular cAMP were also observed. Ro-20-1724 (PDE-IV inhibitor), but not milrinone (PDE-III inhibitor) nor mmIBMX (PDE-I inhibitor), augmented forskolin-stimulated cAMP levels, suggesting that PDE-IV dominates in FTCs. E2 increased cAMP levels and CREB phosphorylation in FTCs, and these effects were mimicked by EE’s (genistein, 4-hydroxy-2’,4’,6’-trichlorobiphenyl, 4-hydroxy-2’,4’,6’-dichlorobiphenyl). Moreover, the effects of E2 and EE were blocked by the tmAC inhibitor DDA, but not by the ERα/β antagonist ICI182780. Moreover, BAPTA-AM (intracellular-Ca2+ chelator) abrogated the effects of E2, but not genistein, on cAMP suggesting differential involvement of Ca2+. Treatment with non-permeable E2-BSA induced cAMP levels and CREB-phosphorylation; moreover, the stimulatory effects of E2 and EEs on cAMP were blocked by G15, a G protein-coupled estrogen receptor (GPER) antagonist. E2 and IBMX induced cAMP formation was inhibited by LRE1 and DDA suggesting involvement of both tmAC and sAC. Our results provide the first evidence that in FTCs, E2 and EE’s stimulate cAMP synthesis via GPER. Exposure of the FT to EE’s and PDE inhibitors may result in abnormal non-cyclic induction of cAMP levels which may induce deleterious effects on reproduction
Trapping characteristics and parametric shifts in lateral GaN HEMTs with SiOâ‚‚/AlGaN gate stacks
Recovery transients following blocking-state voltage stress are analyzed for two types of AlGaN/GaN HEMTs, one set of devices with thick AlGaN barrier layers and another with recessed-gate geometry and ALD SiOâ‚‚ gate dielectric. Results show temperature-invariant emission processes are present in both devices. Recessed-gate devices with SiOâ‚‚ dielectrics are observed to exhibit simultaneous trapping and emission processes during post-stress recovery
Goal processes & self-efficacy related to psychological distress in head & neck cancer patients and their partners
Purpose and objective of the research: In this cross-sectional study we used a self-regulation perspective to better understand the experience of psychological distress in head & neck (H&N) cancer patients and their partners. We examined which goals they valued and the extent to which patients and partners experience goal disturbance. Furthermore, associations were explored between goal disturbance, goal reengagement, (goal)self-efficacy, and psychological distress. Methods and sample: H&N cancer patients and their partners, recruited from the Erasmus Medical Center Rotterdam (N = 40), were interviewed and completed questionnaires, assessing the above aspects of the self-regulation theory. Key results: H&N cancer patients and their partners experienced goal disturbance from the disease. Such disturbances were in patients significantly related to more psychological distress. Higher levels of goal re-engagement were related to less psychological distress, again only significantly in patients. More self-efficacy was significantly associated with less psychological distress in both patients and partners. Conclusions: Self-regulation abilities as goal re-engagement and self-efficacy may be screened and used as target in future psychological interventions, given their potential to decrease perceived psychological distress. In view of elevated levels of goal disturbances in partners, psychological support for caring relatives in such interventions is recommended. (c) 2010 Published by Elsevier Ltd
Statin use and risk of developing diabetes: results from the Diabetes Prevention Program
Objective
Several clinical trials of cardiovascular disease prevention with statins have reported increased risk of type 2 diabetes (T2DM) with statin therapy. However, participants in these studies were at relatively low risk for diabetes. Further, diabetes was often based on self-report and was not the primary outcome. It is unknown whether statins similarly modify diabetes risk in higher risk populations.
Research design and methods
During the Diabetes Prevention Program Outcomes Study (n=3234), the long-term follow-up to a randomized clinical trial of interventions to prevent T2DM, incident diabetes was assessed by annual 75 g oral glucose tolerance testing and semiannual fasting glucose. Lipid profile was measured annually, with statin treatment determined by a participant’s own physician outside of the protocol. Statin use was assessed at baseline and semiannual visits.
Results
At 10 years, the cumulative incidence of statin initiation prior to diabetes diagnosis was 33%–37% among the randomized treatment groups (p=0.36). Statin use was associated with greater diabetes risk irrespective of treatment group, with pooled HR (95% CI) for incident diabetes of 1.36 (1.17 to 1.58). This risk was not materially altered by adjustment for baseline diabetes risk factors and potential confounders related to indications for statin therapy.
Conclusions
In this population at high risk for diabetes, we observed significantly higher rates of diabetes with statin therapy in all three treatment groups. Confounding by indication for statin use does not appear to explain this relationship. The effect of statins to increase diabetes risk appears to extend to populations at high risk for diabetes.
Trial registration number
NCT00038727; Results
A study on text-score disagreement in online reviews
In this paper, we focus on online reviews and employ artificial intelligence
tools, taken from the cognitive computing field, to help understanding the
relationships between the textual part of the review and the assigned numerical
score. We move from the intuitions that 1) a set of textual reviews expressing
different sentiments may feature the same score (and vice-versa); and 2)
detecting and analyzing the mismatches between the review content and the
actual score may benefit both service providers and consumers, by highlighting
specific factors of satisfaction (and dissatisfaction) in texts.
To prove the intuitions, we adopt sentiment analysis techniques and we
concentrate on hotel reviews, to find polarity mismatches therein. In
particular, we first train a text classifier with a set of annotated hotel
reviews, taken from the Booking website. Then, we analyze a large dataset, with
around 160k hotel reviews collected from Tripadvisor, with the aim of detecting
a polarity mismatch, indicating if the textual content of the review is in
line, or not, with the associated score.
Using well established artificial intelligence techniques and analyzing in
depth the reviews featuring a mismatch between the text polarity and the score,
we find that -on a scale of five stars- those reviews ranked with middle scores
include a mixture of positive and negative aspects.
The approach proposed here, beside acting as a polarity detector, provides an
effective selection of reviews -on an initial very large dataset- that may
allow both consumers and providers to focus directly on the review subset
featuring a text/score disagreement, which conveniently convey to the user a
summary of positive and negative features of the review target.Comment: This is the accepted version of the paper. The final version will be
published in the Journal of Cognitive Computation, available at Springer via
http://dx.doi.org/10.1007/s12559-017-9496-
“Yes, I Can”: the protective role of personal self-efficacy in hindering counterproductive work behavior under stressful conditions
Within the stressor-emotion model, counterproductive work behavior (CWB) is considered a possible result of stress. It is well-known that self-efficacy mitigates the detrimental effects of stress and the stressor-strain relation. We aim to extend the stressor-emotion model of CWB by examining the additive and moderating role of work and regulatory emotional self-efficacy dimensions
- …