Refinements in stress echocardiographic techniques improve inter-institutional agreement in interpretation of dobutamine stress echocardiograms

Aims To determine the degree of inter-institutional agreement in the assessment of dobutamine stress echocardiograms using modern stress echo cardiographic technology in combination with standardized data acquisition and assessment criteria. Method and Results Among six experienced institutions, 150 dobutamine stress echocardiograms (dobutamine up to 40 mug.kg(-1) min(-1) and atropine up to I mg) were performed on patients with suspected coronary artery disease using fundamental and harmonic imaging following a consistent digital acquisition protocol. Each dobutamine stress echocardiogram was assessed at every institution regarding endocardial visibility and left ventricular wall motion without knowledge of any other data using standardized reading criteria. No patients were excluded due to poor image quality or inadequate stress level. Coronary angiography was performed within 4 weeks. Coronary angiography demonstrated significant coronary artery disease (less than or equal to50% diameter stenosis) in 87 patients. Using harmonic imaging an average of 5.2+/-0.9 institutions agreed on dobutamine stress echocardiogram results as being normal or abnormal (mean kappa 0.55; 95% CI 0.50-0.60). Agreement was higher in patients with no (equal assessment of dobutamine stress echocardiogram results by 5.5 +/- 0.8 institutions) or three-vessel coronary artery disease (5.4 +/- 0.8 institutions) and lower in one- or two- vessel disease (5.0 +/- 0.9 and 5.2 +/- 1.0 institutions, respectively-, P=0.041). Disagreement on test results was greater in only minor wall motion abnormalities. Agreement on dobutamine stress echocardiogram results was lower using fundamental imaging (mean kappa 0.49; 95% CI 0.44-0.54; P

Virulence of Streptococcus pneumoniae: PsaA mutants are hypersensitive to oxidative stress

psaA encodes a 37-kDa pneumococcal lipoprotein which is part of an ABC Mn(II) transport complex. Streptococcus pneumoniae D39 psaA mutants have previously been shown to be significantly less virulent than wild-type D39, but the mechanism underlying the attenuation has not been resolved. In this study, we have shown that psaA and psaD mutants are highly sensitive to oxidative stress, i.e., to superoxide and hydrogen peroxide, which might explain why they are less virulent than the wild-type strain. Our investigations revealed altered expression of the key oxidative-stress response enzymes superoxide dismutase and NADH oxidase in psaA and psaD mutants, suggesting that PsaA and PsaD may play important roles in the regulation of expression of oxidative-stress response enzymes and intracellular redox homeostasis.

Acute stress hyperglycemia in cats is associated with struggling and increased concentrations of lactate and norepinephrine

We characterized the changes in blood glucose concentrations in healthy cats exposed to a short stressor and determined the associations between glucose concentrations, behavioral indicators of stress, and blood variables implicated in stress hyperglycemia (plasma glucose, lactate, insulin, glucagon, cortisol, epinephrine, and norepinephrine concentrations). Twenty healthy adult cats with normal glucose tolerance had a 5-minute spray bath. Struggling and vocalization were the most frequent behavioral responses. There was a strong relationship between struggling and concentrations of glucose and lactate. Glucose and lactate concentrations increased rapidly and significantly in all cats in response to bathing, with peak concentrations occurring at the end of the bath (glucose baseline 83 mg/dL, mean peak 162 mg/dL; lactate baseline 6.3 mg/dL, mean peak 64.0 mg/dL). Glucose response resolved within 90 minutes in 12 of the 20 cats. Changes in mean glucose concentrations were strongly correlated with changes in mean lactate (r =.84; P

Development of a measure of coping with multiple sclerosis caregiving

Development of a self-report measure of coping specific to multiple sclerosis (MS) caregiving is needed to advance our understanding of the role of coping in adaptation to caring for a person with MS and to contribute to a lack of empirical data on MS caregiving. A total of 213 MS caregivers and their care recipients completed a Coping with MS Caregiving Inventory (CMSCI) and measures of adjustment (psychological distress), appraisal and illness. A subsample (n = 64) also completed the Ways of Coping Checklist (WCC) and additional adjustment measures (depression, caregiving impact. dyadic adjustment, and relationship conflict and reciprocity). Factor analyses revealed 5 factors: Supportive Engagement, Criticism and Coercion, Practical Assistance, Avoidance, and Positive Reframing. Subscales had internal reliabilities comparable to similar scales and were empirically distinct. Preliminary construct validation data are consistent with recent MS caregiving research that links passive avoidant emotion-focused coping with poorer adjustment, and relationship-focused coping caregiving research that links greater reliance on positive relationship-focused coping and less reliance on criticism with better adjustment. Results extend this research by revealing new relations between coping and adaptation to MS caregiving. Convergent validation data suggest that although the inventory differs from the WCC, it does share certain conceptual similarities with this scale.

Development of the HIV/AIDS stress scale

Development of a self-report measure of stress specific to HIV/AIDS is needed to advance our understanding of the role of stress in adaptation to HIV/AIDS: hence, the aim of this study was the development of the HIV/AIDS Stress Scale. A total of 132 homosexual/bisexual men with HIV/AIDS v ere interviewed and completed the HIV/AIDS Stress Scale and measures of coping strategies, appraisal, social support and adjustment (global distress, depression, social adjustment, number of HIV symptoms, and subjective health status) at three time points. Thirty-nine primary caregivers were interviewed and completed measures of stress and adjustment. Exploratory factor analyses of the HIV/AIDS Stress Scale items revealed three factors: Social, Instrumental and Emotional/Existential Stress. Factors had adequate internal reliabilities and were stable over 12 months. Construct validation data are consistent with recent stress/coping research that links higher levels of stress with more HIV symptoms. reliance on emotion-focused coping, lower social support, poorer levels of adjustment and higher levels of caregiver stress. Results extend this research by revealing new differential relations between various stress dimensions and stress/coping variables. Convergent validation data suggest that the HIV/AIDS Stress Scale shares conceptual similarity with threat appraisal. and differs from control liability and challenge appraisals. The HIV/AIDS Stress Scale shows potential for the elucidation of the role of stress in coping and adaptation to HIV/AIDS and disease progression in both research and clinical applications.

Adjustment of homeless adolescents to a crisis shelter: Application of a stress and coping model

The present study examined the utility of a stress and coping model of adaptation to a homeless shelter among homeless adolescents. Seventy-eight homeless adolescents were interviewed and completed self-administered scales at Time 1 (day of shelter entry) and Time 2 (day of discharge). The mean duration of stay at the shelter was 7.23 days (SD = 7.01). Predictors included appraisal (threat and self-efficacy), coping resources, and coping strategies (productive, nonproductive, and reference to others coping). Adjustment outcomes were Time I measures of global distress, physical health, clinician-and youthworker- rated social adjustment, and externalizing behavior and Time 2 youthworker-rated social adjustment and goal achievement. Results of hierarchical regression analyses indicated that after controlling for the effects of relevant background variables (number of other shelters visited, sexual, emotional, and physical abuse), measures of coping resources, appraisal, and coping strategies evidenced distinct relations with measures of adjustment in ways consistent with the model's predictions with few exceptions. In cross-sectional analyses better Time I adjustment was related to reports of higher levels of coping resources, self-efficacy beliefs, and productive coping strategies, and reports of lower levels of threat appraisal and nonproductive coping strategies. Prospective analyses showed a link between reports of higher levels of reference to others coping strategies and greater goal achievement and, unexpectedly, an association between lower self-efficacy beliefs and better Time 2 youthworker-rated social adjustment. Hence, whereas prospective analyses provide only limited support for the use of a stress and coping model in explaining the adjustment of homeless adolescents to a crisis shelter, cross-sectional findings provide stronger support.

Relationship between stress-induced martensitic transformation and impact toughness in low carbon austenitic steels

The effect of test temperature, which controls the stability of austenite, on the impact toughness of a low carbon Fe-Ni-Mn-C austenitic steel and 304 stainless steel, has been investigated. Under impact conditions, stress-induced martensitic transformation occurred, in a region near the fracture surface, at test temperatures below 80degreesC for the Fe-Ni-Mn-C steel and below -25degreesC for 304 stainless steel. The former shows significant transformation toughening and the highest impact toughness was obtained at 10degreesC, which corresponds to the maximum amount of martensite formed by stress-induced transformation above the Ms temperature. The stress-induced martensitic transformation contributes negatively to the impact toughness in the 304 stainless steel. Increasing the amount of stress-induced transformation to martensite, lowered the impact toughness. The experimental results can be well explained by the Antolovich theory through the analysis of metallography and fractography. The different effect of stress-induced transformation on the impact toughness in Fe-Ni-Mn-C steel and 304 stainless steel has been further understood by applying the crystallographic model for stress-induced martensitic transformation to these two steels. (C) 2002 Kluwer Academic Publishers.

Adjustment to chronic obstructive pulmonary disease: the importance of psychological factors

Research has indicated a weak relationship between the degree of physical problems and quality of life in patients with chronic obstructive pulmonary disease (COPD). The importance of adaptive psychological functioning to maintain optimum quality of life has long been recognized, but there is a lack of empirical evidence concerning the nature of psychological factors involved in adjustment to COPD. Ninety-two males completed questionnaires to determine their coping strategies, levels of self-efficacy of symptom management and social support. Adjustment was measured in terms of depression, anxiety and quality of life. Symptom severity, socioeconomic status, duration of disease and age, which have been demonstrated to be of consequence in COPD, were used as control variables in hierarchical multiple regression analyses. Higher levels of catastrophic withdrawal coping strategies and lower levels of self-efficacy of symptom management were associated with higher levels of depression, anxiety and a reduced quality of life. Higher levels of positive social support were linked to lower levels of depression and anxiety, while higher levels of negative social support were linked to higher levels of depression and anxiety. To maximize quality of life in patients with chronic obstructive pulmonary disease, psychological factors need to be carefully assessed and addressed.

The impact of participation in activities while on vacation on senior's psychological well-being: A path model application

This article extends earlier research regarding the relationships between senior travelers’ participation in activities while on vacation, their overall satisfaction with their travel experiences, and their psychological well-being. A path model was developed to depict the direct and indirect relationships between these variables by using a sample of senior tourists traveling on North American escorted tour itineraries. Whereas the direct effect accounted for 98% of the relationships between the senior tourists’ levels of participation in activities and their psychological well-being, the indirect effect was negligible. The study concluded that senior tourists’activity levels were significantly related to their psychological well-being, but their satisfaction with the tours was not.

Osmoregulative capacity in birdseed millet under conditions of water stress. I. Variation in Setaria italica and Panicum miliaceum

Experiments involving 14 accessions of Panicum miliaceum L. (Proso millet) and 11 accessions of Setaria italica L. (Foxtail millet) have demonstrated variability in the degree of osmoregulative capacity among these accessions. Birdseed millet is generally claimed to be sensitive to drought stress, apparently because of a shallow root system. Accessions with high osmoregulative capacity demonstrate at least some drought tolerance. Osmoregulative capacity was measured on flag leaves of headed millet plants in pots undergoing water stress in a controlled environment chamber. Osmoregulative capacity was determined from the relationship between osmotic potential and leaf water potential; and the logarithmic relationship between osmotic potential and relative water content. The group of accessions of S. italica showed an overall level of osmoregulative capacity which was greater than that observed for the group of P. miliaceum accessions. Four accessions of S. italica (108042, 108463, 108541 and 108564) and one accession of P. miliaceum (108104) demonstrated high osmoregulative capacity. Differences of 1.05 MPa or more between observed and estimated osmotic potential were found at relative water contents of 80 % among these accessions. The extent of osmoregulative capacity was associated with osmotic potential at full turgor and the rate of decline in osmotic potential as leaf water potentail declined.

Should we debrief and counsel people who have had psychological shock?

Design: Randomised controlled trial of psychological debriefing. Setting: A British teaching hospital (the Radcliffe Hospital, Oxford). Patients: 66 men and 40 women, aged 17–69 years, admitted to hospital after a motor vehicle accident. Most had been the driver of a car. Median admission duration was four days for the 52 control patients and eight days for the 54 who underwent the intervention. Interventions: A debriefing of about one hour on Day 2 of admission, encouraging patients to describe the accident and express their emotions, followed by a cognitive appraisal which included describing common reactions to traumatic experiences and suggesting a range of people who might be able to assist in the future, including the patient's general practitioner. 91 patients were assessed at four months and 61 were assessed at three years. Control patients had no debriefing or counselling. Main outcome measures: Impact of Event Scale (IES, which focuses on intrusive thoughts and avoidance of similar situations to the event); Brief Symptom Inventory (BSI, a measure of 53 symptoms); and other questions related to physical pain and functional activities. Main results: At four months there was still considerable psychological morbidity among the patients who were followed up. There was a significant difference (P < 0.05) in changes of IES between the 42 who received the intervention, in whom it increased from 15 (standard deviation [SD], 15) to 16 (SD, 15), and the 49 controls, in whom it fell from 15 (SD, 12) to 13 (SD, 14). Similarly, two subscales of the BSI score changed significantly between the intervention group, among whom it deteriorated from 0.5 (SD, 0.5) to 0.6 (SD, 0.8), and the control s, in whom it hardly changed from 0.4 (SD, 0.3) to 0.4 (SD, 0.4). Among the 61 patients followed for three years, the 30 randomised to receive the intervention were significantly worse, by self-report, both psychologically and physically. Their mean IES score deteriorated from a baseline of 15 (SD, 14) to 16 (SD, 18). In comparison, scores for the 31 control patients improved from 16 (SD, 12) to 13 (SD, 17). The difference in change was significant (P < 0.05). Among all patients with high initial scores, these decreased among the controls but not among those receiving the intervention. Conclusion: Psychological counselling should only be used in the context of trials rather than routine care.

Harmful drinking in military veterans with post-traumatic stress disorder: Association with the D2 dopamine receptor A1 allele

Aims: The frequency of the Taq I A alleles (A1 and A2) of the D2 dopamine receptor (DRD2) gene was examined in Caucasian post-traumatic stress disorder (PTSD) patients and controls. Results: In 91 PTSD patients, the frequency of the A1 allele was higher (P = 6.12 x 10(-3)) than in the 51 controls. In the 38 PTSD harmful drinkers (greater than or equal to60 g alcohol/day), A1 allelic frequency was higher (P = 3.91 x 10(-2)) than in the 53 non-harmful drinkers (

Stress correlation function evolution in lattice solid elasto-dynamic models of shear and fracture zones and earthquake prediction

It has been argued that power-law time-to-failure fits for cumulative Benioff strain and an evolution in size-frequency statistics in the lead-up to large earthquakes are evidence that the crust behaves as a Critical Point (CP) system. If so, intermediate-term earthquake prediction is possible. However, this hypothesis has not been proven. If the crust does behave as a CP system, stress correlation lengths should grow in the lead-up to large events through the action of small to moderate ruptures and drop sharply once a large event occurs. However this evolution in stress correlation lengths cannot be observed directly. Here we show, using the lattice solid model to describe discontinuous elasto-dynamic systems subjected to shear and compression, that it is for possible correlation lengths to exhibit CP-type evolution. In the case of a granular system subjected to shear, this evolution occurs in the lead-up to the largest event and is accompanied by an increasing rate of moderate-sized events and power-law acceleration of Benioff strain release. In the case of an intact sample system subjected to compression, the evolution occurs only after a mature fracture system has developed. The results support the existence of a physical mechanism for intermediate-term earthquake forecasting and suggest this mechanism is fault-system dependent. This offers an explanation of why accelerating Benioff strain release is not observed prior to all large earthquakes. The results prove the existence of an underlying evolution in discontinuous elasto-dynamic, systems which is capable of providing a basis for forecasting catastrophic failure and earthquakes.

Photosynthetic responses of the coral Montipora digitata to cold temperature stress

Coral bleaching events have become more frequent and widespread, largely due to elevated sea surface temperatures. Global climate change could lead to increased variability of sea surface temperatures, through influences on climate systems, e.g. El Nino Southern Oscillation (ENSO). Field observations in 1999, following a strong ENSO, revealed that corals bleached in winter after unusually cold weather. To explore the basis for these observations, the photosynthetic responses of the coral species Montipora digitata Studer were investigated in a series of temperature and light experiments. Small replicate coral colonies were exposed to ecologically relevant lower temperatures for varying durations and under light regimes that ranged from darkness to full sunlight. Photosynthetic efficiency was analyzed using a pulse amplitude modulated (PAM) fluorometer (F-0, F-m, F-v/F-m), and chlorophyll a (chl a) content and symbiotic dinoflagellate density were analyzed with spectrophotometry and microscopy, respectively. Cold temperature stress had a negative impact on M digitata colonies indicated by decreased photosynthetic efficiency (F-v/F-m), loss of symbiotic dinoflagellates and changes in photosynthetic pigment concentrations. Corals in higher light regimes were more susceptible to cold temperature stress, Moderate cold stress resulted in photoacclimatory responses, but severe cold stress resulted in photodamage, bleaching and increased mortality. Responses to cold temperature stress of M digitata appeared similar to that observed in corals exposed to warmer than normal temperatures, suggesting a common mechanism. The results of this study suggest that corals and coral reefs may also be impacted by exposure to cold as well as warm temperature extremes as climate change occurs.