977 resultados para Stress Fracture
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Preterm birth may represent a traumatic situation for both parents and a stressful situation for the infant, potentially leading to difficulties in mother-infant relationships. This study aimed to investigate the impact of an early intervention on maternal posttraumatic stress symptoms, and on the quality of mother-infant interactions, in a sample of very preterm infants and their mothers. Half of the very preterm infants involved in the study (n=26) were randomly assigned to a 3-step early intervention program (at 33 and 42 weeks after conception and at 4 months' corrected age). Both groups of preterm infants (with and without intervention) were compared to a group of full-term infants. The impact of the intervention on maternal posttraumatic stress symptoms was assessed 42 weeks after conception and when the infants were 4 and 12 months of age. The impact of the intervention on the quality of mother-infant interactions was assessed when the infants were 4 months old. Results showed a lowering of mothers' posttraumatic stress symptoms between 42 weeks and 12 months in the group of preterm infants who received the intervention. Moreover, an enhancement in maternal sensitivity and infant cooperation during interactions was found at 4 months in the group with intervention. In the case of a preterm birth, an early intervention aimed at enhancing the quality of the mother-infant relationship can help to alleviate maternal post-traumatic stress symptoms and may have a positive impact on the quality of mother-infant interactions.
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Endocannabinoids and cannabinoid 1 (CB(1)) receptors have been implicated in cardiac dysfunction, inflammation, and cell death associated with various forms of shock, heart failure, and atherosclerosis, in addition to their recognized role in the development of various cardiovascular risk factors in obesity/metabolic syndrome and diabetes. In this study, we explored the role of CB(1) receptors in myocardial dysfunction, inflammation, oxidative/nitrative stress, cell death, and interrelated signaling pathways, using a mouse model of type 1 diabetic cardiomyopathy. Diabetic cardiomyopathy was characterized by increased myocardial endocannabinoid anandamide levels, oxidative/nitrative stress, activation of p38/Jun NH(2)-terminal kinase (JNK) mitogen-activated protein kinases (MAPKs), enhanced inflammation (tumor necrosis factor-α, interleukin-1β, cyclooxygenase 2, intracellular adhesion molecule 1, and vascular cell adhesion molecule 1), increased expression of CB(1), advanced glycation end product (AGE) and angiotensin II type 1 receptors (receptor for advanced glycation end product [RAGE], angiotensin II receptor type 1 [AT(1)R]), p47(phox) NADPH oxidase subunit, β-myosin heavy chain isozyme switch, accumulation of AGE, fibrosis, and decreased expression of sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase (SERCA2a). Pharmacological inhibition or genetic deletion of CB(1) receptors attenuated the diabetes-induced cardiac dysfunction and the above-mentioned pathological alterations. Activation of CB(1) receptors by endocannabinoids may play an important role in the pathogenesis of diabetic cardiomyopathy by facilitating MAPK activation, AT(1)R expression/signaling, AGE accumulation, oxidative/nitrative stress, inflammation, and fibrosis. Conversely, CB(1) receptor inhibition may be beneficial in the treatment of diabetic cardiovascular complications.
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Parental effort is usually associated with high metabolism that could lead to an increase in the production of reactive oxidative species giving rise to oxidative stress. Since many antioxidants involved in the resistance to oxidative stress can also enhance immune function, an increase in parental effort may diminish the level of antioxidants otherwise involved in parasite resistance. In the present study, we performed brood size manipulation in a population of great tits (Parus major) to create different levels of parental effort. We measured resistance to oxidative stress and used a newly developed quantitative PCR assay to quantify malarial parasitaemia. We found that males with an enlarged brood had significantly higher level of malarial parasites and lower red blood cell resistance to free radicals than males rearing control and reduced broods. Brood size manipulation did not affect female parasitaemia, although females with an enlarged brood had lower red blood cell resistance than females with control and reduced broods. However, for both sexes, there was no relationship between the level of parasitaemia and resistance to oxidative stress, suggesting a twofold cost of reproduction. Our results thus suggest the presence of two proximate and independent mechanisms for the well-documented trade-off between current reproductive effort and parental survival.
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Introduction The benefit of stress ulcer prophylaxis (SUP) in noncriticallyill patients has not been proved. Over-prescription of SUP isnot devoided of risks (i.e. drug-drug interactions, adverse events).This prospective study aimed to evaluate the use of proton pumpinhibitors (PPIs) for SUP in a visceral surgery ward.Materials & Methods Data collection was performed prospectivelyduring a 8-week period on patients hospitalized in a visceral surgeryward (58 beds). Patients with a PPI prescription for the treatment ofulcers, gastroesophageal reflux disease, esophagitis or epigastralgiawere excluded as well as patients hospitalized twice during the studyperiod. The American Society of Health-System Pharmacists guidelineson SUP were used to assess the appropriateness of de novo PPIprescriptions.Results Among 255 patients in the study, 138 (54.1%) received aprophylaxis with PPI, of which 86 (62.3%) were de novo PPI prescriptions.93.5% of patients received esomeprazole (according to thehospital drug formulary) mainly orally at 40 mg qd. 79.1% of patientshad no risk factors for SUP. 17.9% and 3.0% had one and two riskfactors, respectively. 95% of the patients with PPI were not hospitalizedin the intensive care unit (ICU) before their stay in the visceralsurgery ward. At discharge, PPI therapy was continued in 34.2% ofpatients with a de novo PPI prescription.Discussion & Conclusion This study highlights the over-utilizationof PPIs in non-ICU patients and the inappropriate continuation of PPIprescriptions at discharge. The PPI dosage prescribed for prophylaxiswas probably too high compared with the data of the literature.Treatment recommendations for SUP are needed to restrict PPIuse for justified indications.
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PURPOSE: To assess (1) the lifetime prevalence of exposure both to trauma and post-traumatic stress disorder (PTSD); (2) the risk of PTSD by type of trauma; and (3) the determinants of the development of PTSD in the community. METHODS: The Diagnostic Interview for Genetic Studies was administered to a random sample of an urban area (N = 3,691). RESULTS: (1) The lifetime prevalence estimates of exposure to trauma and PTSD were 21.0 and 5.0%; respectively, with a twice as high prevalence of PTSD in women compared to men despite a similar likelihood of exposure in the two sexes; (2) Sexual abuse was the trauma involving the highest risk of PTSD; (3) The risk of PTSD was most strongly associated with sexual abuse followed by preexisting bipolar disorder, alcohol dependence, antisocial personality, childhood separation anxiety disorder, being victim of crime, witnessing violence, Neuroticism and Problem-focused coping strategies. After adjustment for these characteristics, female sex was no longer found to be significantly associated with the risk of PTSD. CONCLUSIONS: The risk for the development of PTSD after exposure to traumatic events is associated with several factors including the type of exposure, preexisting psychopathology, personality features and coping strategies which independently contribute to the vulnerability to PTSD.
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BACKGROUND: Chronic endoplasmic reticulum (ER) stress contributes to the apoptotic cell death in the myocardium, thereby playing a critical role in the development of cardiomyopathy. ER stress has been reported to be induced after high-fat diet feeding in mice and also after saturated fatty acid treatment in vitro. Therefore, since several studies have shown that peroxisome proliferator-activated receptor (PPAR)β/δ inhibits ER stress, the main goal of this study consisted in investigating whether activation of this nuclear receptor was able to prevent lipid-induced ER stress in cardiac cells. METHODS AND RESULTS: Wild-type and transgenic mice with reduced PPARβ/δ expression were fed a standard diet or a high-fat diet for two months. For in vitro studies, a cardiomyocyte cell line of human origin, AC16, was treated with palmitate and the PPARβ/δ agonist GW501516. Our results demonstrate that palmitate induced ER stress in AC16 cells, a fact which was prevented after PPARβ/δ activation with GW501516. Interestingly, the effect of GW501516 on ER stress occurred in an AMPK-independent manner. The most striking result of this study is that GW501516 treatment also upregulated the protein levels of beclin 1 and LC3II, two well-known markers of autophagy. In accordance with this, feeding on a high-fat diet or suppression of PPARβ/δ in knockout mice induced ER stress in the heart. Moreover, PPARβ/δ knockout mice also displayed a reduction in autophagic markers. CONCLUSION: Our data indicate that PPARβ/δ activation might be useful to prevent the harmful effects of ER stress induced by saturated fatty acids in the heart by inducing autophagy.
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OBJECTIVES: Studies of small area variations of health care utilization are more and more frequent. Such variations are often considered to be an indication of variations in the quality of medical care. The variations in the rate of operations for hip fractures are among the lowest studied to date, due to the fact that a consensus exists concerning this surgery. Our objective is to examine these variations within the context of relatively small and heterogeneous districts. METHOD: Based on anonymous computerized data on public hospital stays, this study describes the variations in population rates (crude and standardized) of operations for hip fracture among the health districts of the Canton of Vaud for the period from 1986 to 1991. District populations vary from 22,000 to 164,000. Using the extremal quotient (EQ), the importance of these variations was determined. RESULTS: The study population consists of 2363 cases, of which 78% are women. Mean age is 80.4 for women and 70.6 for men. Standardized rates of operation for hip fracture per 100,000 in the Canton Vaud for the years 1986 to 1991 are, respectively: 56; 67; 86; 91; 89 and 94. The EQ for the years 1986 to 1991 are respectively: 8.2; 4.0; 3.5; 2.7; 1.9 and 1.9. The high EQ, especially for the earlier years, are contrary to the initial premise of absence of variation. The progressive implementation in the Canton Vaud of VESKA medical statistics could play a role, as could the small size of many of the districts, with resultant instability of rates. CONCLUSIONS: Considering the wide variations shown here for an operation hardly regarded as subject to variations, it is important to exercise caution in interpreting published data of small area variations.
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Large Dynamic Message Signs (DMSs) have been increasingly used on freeways, expressways and major arterials to better manage the traffic flow by providing accurate and timely information to drivers. Overhead truss structures are typically employed to support those DMSs allowing them to provide wider display to more lanes. In recent years, there is increasing evidence that the truss structures supporting these large and heavy signs are subjected to much more complex loadings than are typically accounted for in the codified design procedures. Consequently, some of these structures have required frequent inspections, retrofitting, and even premature replacement. Two manufacturing processes are primarily utilized on truss structures - welding and bolting. Recently, cracks at welding toes were reported for the structures employed in some states. Extremely large loads (e.g., due to high winds) could cause brittle fractures, and cyclic vibration (e.g., due to diurnal variation in temperature or due to oscillations in the wind force induced by vortex shedding behind the DMS) may lead to fatigue damage, as these are two major failures for the metallic material. Wind and strain resulting from temperature changes are the main loads that affect the structures during their lifetime. The American Association of State Highway and Transportation Officials (AASHTO) Specification defines the limit loads in dead load, wind load, ice load, and fatigue design for natural wind gust and truck-induced gust. The objectives of this study are to investigate wind and thermal effects in the bridge type overhead DMS truss structures and improve the current design specifications (e.g., for thermal design). In order to accomplish the objective, it is necessary to study structural behavior and detailed strain-stress of the truss structures caused by wind load on the DMS cabinet and thermal load on the truss supporting the DMS cabinet. The study is divided into two parts. The Computational Fluid Dynamics (CFD) component and part of the structural analysis component of the study were conducted at the University of Iowa while the field study and related structural analysis computations were conducted at the Iowa State University. The CFD simulations were used to determine the air-induced forces (wind loads) on the DMS cabinets and the finite element analysis was used to determine the response of the supporting trusses to these pressure forces. The field observation portion consisted of short-term monitoring of several DMS Cabinet/Trusses and long-term monitoring of one DMS Cabinet/Truss. The short-term monitoring was a single (or two) day event in which several message sign panel/trusses were tested. The long-term monitoring field study extended over several months. Analysis of the data focused on trying to identify important behaviors under both ambient and truck induced winds and the effect of daily temperature changes. Results of the CFD investigation, field experiments and structural analysis of the wind induced forces on the DMS cabinets and their effect on the supporting trusses showed that the passage of trucks cannot be responsible for the problems observed to develop at trusses supporting DMS cabinets. Rather the data pointed toward the important effect of the thermal load induced by cyclic (diurnal) variations of the temperature. Thermal influence is not discussed in the specification, either in limit load or fatigue design. Although the frequency of the thermal load is low, results showed that when temperature range is large the restress range would be significant to the structure, especially near welding areas where stress concentrations may occur. Moreover stress amplitude and range are the primary parameters for brittle fracture and fatigue life estimation. Long-term field monitoring of one of the overhead truss structures in Iowa was used as the research baseline to estimate the effects of diurnal temperature changes to fatigue damage. The evaluation of the collected data is an important approach for understanding the structural behavior and for the advancement of future code provisions. Finite element modeling was developed to estimate the strain and stress magnitudes, which were compared with the field monitoring data. Fatigue life of the truss structures was also estimated based on AASHTO specifications and the numerical modeling. The main conclusion of the study is that thermal induced fatigue damage of the truss structures supporting DMS cabinets is likely a significant contributing cause for the cracks observed to develop at such structures. Other probable causes for fatigue damage not investigated in this study are the cyclic oscillations of the total wind load associated with the vortex shedding behind the DMS cabinet at high wind conditions and fabrication tolerances and induced stresses due to fitting of tube to tube connections.
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Even though laboratory evolution experiments have demonstrated genetic variation for learning ability, we know little about the underlying genetic architecture and genetic relationships with other ecologically relevant traits. With a full diallel cross among twelve inbred lines of Drosophila melanogaster originating from a natural population (0.75 < F < 0.93), we investigated the genetic architecture of olfactory learning ability and compared it to that for another behavioral trait (unconditional preference for odors), as well as three traits quantifying the ability to deal with environmental challenges: egg-to-adult survival and developmental rate on a low-quality food, and resistance to a bacterial pathogen. Substantial additive genetic variation was detected for each trait, highlighting their potential to evolve. Genetic effects contributed more than nongenetic parental effects to variation in traits measured at the adult stage: learning, odorant perception, and resistance to infection. In contrast, the two traits quantifying larval tolerance to low-quality food were more strongly affected by parental effects. We found no evidence for genetic correlations between traits, suggesting that these traits could evolve at least to some degree independently of one another. Finally, inbreeding adversely affected all traits.
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CONTEXT: In the Health Outcomes and Reduced Incidence with Zoledronic Acid Once Yearly - Pivotal Fracture Trial (HORIZON-PFT), zoledronic acid (ZOL) 5 mg significantly reduced fracture risk. OBJECTIVE: The aim of the study was to identify factors associated with greater efficacy during ZOL 5 mg treatment. DESIGN, SETTING, AND PATIENTS: We conducted a subgroup analysis (preplanned and post hoc) of a multicenter, double-blind, placebo-controlled, 36-month trial in 7765 women with postmenopausal osteoporosis. Intervention: A single infusion of ZOL 5 mg or placebo was administered at baseline, 12, and 24 months. MAIN OUTCOME MEASURES: Primary endpoints were new vertebral fracture and hip fracture. Secondary endpoints were nonvertebral fracture and change in femoral neck bone mineral density (BMD). Baseline risk factor subgroups were age, BMD T-score and vertebral fracture status, total hip BMD, race, weight, geographical region, smoking, height loss, history of falls, physical activity, prior bisphosphonates, creatinine clearance, body mass index, and concomitant osteoporosis medications. RESULTS: Greater ZOL induced effects on vertebral fracture risk were seen with younger age (treatment-by-subgroup interaction, P = 0.05), normal creatinine clearance (P = 0.04), and body mass index >or= 25 kg/m(2) (P = 0.02). There were no significant treatment-factor interactions for hip or nonvertebral fracture or for change in BMD. CONCLUSIONS: ZOL appeared more effective in preventing vertebral fracture in younger women, overweight/obese women, and women with normal renal function. ZOL had similar effects irrespective of fracture risk factors or femoral neck BMD.
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OBJECTIVE: Critical care is a working environment with frequent exposure to stressful events. High levels of psychological stress have been associated with increased prevalence of burnout. Psychological distress acts as a potent trigger of cortisol secretions. We attempted to objectify endocrine stress reactivity. DESIGN: Observational cohort study during two 12-day periods in successive years. SETTING: A tertiary multidisciplinary neonatal and pediatric intensive care unit (33 beds). SUBJECTS: One hundred and twelve nurses and 27 physicians (94% accrual rate). INTERVENTIONS AND MEASUREMENTS: Cortisol determined from salivary samples collected every 2 hrs and after stressful events. Participants recorded the subjective perception of stress with every sample. Endocrine reactions were defined as transient surges in cortisol of >50% and 2.5 nmol/L over the baseline. MAIN RESULTS: During 7,145 working hours, we observed 474 (12.5%) endocrine reactions from 3,781 samples. The mean cortisol increase amounted to 10.6 nmol/L (219%). The mean occurrence rate of endocrine reactions per subject and sample was 0.159 (range, 0-0.43). Although the mean raw cortisol levels were lower in experienced team members (>3 yrs of intensive care vs. <3 yrs, 4.1 vs. 4.95 nmol/L, p < .001), professional experience failed to attenuate the frequency and magnitude of endocrine reactions, except for the subgroup of nurses and physicians with >8 yrs of intensive care experience. A high proportion (71.3%) of endocrine reactions occurred without conscious perception of stress. Unawareness of stress was higher in intensive care nurses (75.1%) than in intermediate care nurses (51.8%, p < .01). CONCLUSIONS: Stress-related cortisol surges occur frequently in neonatal and pediatric critical care staff. Cortisol increases are independent of subjective stress perception. Professional experience does not abate the endocrine stress reactivity.
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A role for gut hormone in bone physiology has been suspected. We evidenced alterations of microstructural morphology (trabecular and cortical) and bone strength (both at the whole-bone - and tissue-level) in double incretin receptor knock-out (DIRKO) mice as compared to wild-type littermates. These results support a role for gut hormones in bone physiology. INTRODUCTION: The two incretins, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), have been shown to control bone remodeling and strength. However, lessons from single incretin receptor knock-out mice highlighted a compensatory mechanism induced by elevated sensitivity to the other gut hormone. As such, it is unclear whether the bone alterations observed in GIP or GLP-1 receptor deficient animals resulted from the lack of a functional gut hormone receptor, or by higher sensitivity for the other gut hormone. The aims of the present study were to investigate the bone microstructural morphology, as well as bone tissue properties, in double incretin receptor knock-out (DIRKO) mice. METHODS: Twenty-six-week-old DIRKO mice were age- and sex-matched with wild-type (WT) littermates. Bone microstructural morphology was assessed at the femur by microCT and quantitative X-ray imaging, while tissue properties were investigated by quantitative backscattered electron imaging and Fourier-transformed infrared microscopy. Bone mechanical response was assessed at the whole-bone- and tissue-level by 3-point bending and nanoindentation, respectively. RESULTS: As compared to WT animals, DIRKO mice presented significant augmentations in trabecular bone mass and trabecular number whereas bone outer diameter, cortical thickness, and cortical area were reduced. At the whole-bone-level, yield stress, ultimate stress, and post-yield work to fracture were significantly reduced in DIRKO animals. At the tissue-level, only collagen maturity was reduced by 9 % in DIRKO mice leading to reductions in maximum load, hardness, and dissipated energy. CONCLUSIONS: This study demonstrated the critical role of gut hormones in controlling bone microstructural morphology and tissue properties.
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The NLRP3 inflammasome has a major role in regulating innate immunity. Deregulated inflammasome activity is associated with several inflammatory diseases, yet little is known about the signaling pathways that lead to its activation. Here we show that NLRP3 interacted with thioredoxin (TRX)-interacting protein (TXNIP), a protein linked to insulin resistance. Inflammasome activators such as uric acid crystals induced the dissociation of TXNIP from thioredoxin in a reactive oxygen species (ROS)-sensitive manner and allowed it to bind NLRP3. TXNIP deficiency impaired activation of the NLRP3 inflammasome and subsequent secretion of interleukin 1beta (IL-1beta). Akin to Txnip(-/-) mice, Nlrp3(-/-) mice showed improved glucose tolerance and insulin sensitivity. The participation of TXNIP in the NLRP3 inflammasome activation may provide a mechanistic link to the observed involvement of IL-1beta in the pathogenesis of type 2 diabetes.