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Biomedical subjects

Peter Elliott

Publications and source records attributed to Peter Elliott.

At least 19 recordsLinked to original sources
PubMed2006

Resveratrol improves mitochondrial function and protects against metabolic disease by activating SIRT1 and PGC-1alpha.

Diminished mitochondrial oxidative phosphorylation and aerobic capacity are associated with reduced longevity. We tested whether resveratrol (RSV), which is known to extend lifespan, impacts mitochondrial function and metabolic homeostasis. Treatment of mice with RSV significantly increased their aerobic capacity, as evidenced by their increased running time and consumption of oxygen in muscle fibers. RSV's effects were associated with an induction of genes for oxidative phosphorylation and mitochondrial biogenesis and were largely explained by an RSV-mediated decrease in PGC-1alpha acetylation and an increase in PGC-1alpha activity. This mechanism is consistent with RSV being a known activator of the protein deacetylase, SIRT1, and by the lack of effect of RSV in SIRT1(-/-) MEFs. Importantly, RSV treatment protected mice against diet-induced-obesity and insulin resistance. These pharmacological effects of RSV combined with the association of three Sirt1 SNPs and energy homeostasis in Finnish subjects implicates SIRT1 as a key regulator of energy and metabolic homeostasis.

Acetylation↗
PubMed2006

PTSD symptom trajectories: from early to chronic response.

This study aimed to identify posttraumatic stress disorder (PTSD) symptom trajectories across the first 12 months following traumatic injury. Three hundred and seven consecutively admitted injury survivors were assessed for severity of PTSD symptoms just prior to discharge, and at 3 and 12 months postinjury. Growth modeling was used to determine the curve that best fit the trajectory for each symptom cluster over the 12-month period. Individuals with 12-month PTSD showed significantly higher re-experiencing, arousal, and avoidance symptoms at eight days posttrauma relative to those without, and these symptoms escalated over time. Those without PTSD maintained their relatively low symptom levels. These findings highlight that individuals who will go onto develop PTSD have a distinctly different symptom course than those who recover.

Adaptation, Psychological↗
PubMed2006

Treatment for combat-related posttraumatic stress disorder: two-year follow-up.

This study reports on outcomes 2 years following completion of specialist veteran posttraumatic stress disorder (PTSD) treatment programs in 2,223 (reduced to 1,508 at 24 months) consecutive admissions. Self-report measures of PTSD, anxiety, depression, anger, alcohol use, and general functioning were obtained at admission, 6, 12, and 24 months after admission. Significant improvements were demonstrated at 6 months, with smaller gains continuing through to 24-month assessment. Within subject effect sizes of around 0.8 were obtained for PTSD and around 0.5 for anxiety and depression. Although lack of a control group limits the extent to which improvements can be attributed to the treatment program, the data suggest that specialized treatment programs for combat-related PTSD continue to be of value.

Alcohol Drinking↗
PubMed2006

Is mixed-handedness a marker of treatment response in posttraumatic stress disorder?: a pilot study.

Recent studies suggest that mixed-handedness is a risk factor for posttraumatic stress disorder (PTSD). This study examined whether mixed-handed veterans with combat-related PTSD respond more poorly to psychosocial treatment. Consistency of hand preference was assessed in 150 Vietnam combat veterans with PTSD using the Edinburgh Handedness Inventory (R. C. Oldfield, 1971). Growth modeling analyses using Mplus (L. K. Muthén & B. Muthén, 2002) identified that PTSD veterans with mixed-handedness reported significantly less treatment improvement on the PTSD Checklist (F. W. Weathers, B. T. Litz, D. S. Herman, J. A. Huska, & T. M. Keane, 1993) than did veterans with consistent handedness. These data suggest that mixed-handedness is associated with poorer PTSD treatment response. Several possible explanations for this finding are discussed.

Combat Disorders↗
PubMed2005

Patterns of treatment response in chronic posttraumatic stress disorder: an application of latent growth mixture modeling.

This study attempts to differentiate groups of individuals who exhibit different patterns of recovery following treatment for chronic posttraumatic stress disorder (PTSD) and describes these groups in terms of relevant characteristics at program intake. A sample of 2,219 Vietnam veterans who had completed a 12-week treatment program was followed up at 6, 12, and 24 months post admission using self-report measures. With change in PTSD symptoms over time as the focus, latent growth mixture modeling was used to assign individual veterans to subgroups. A three-group solution provided the best account of the data. Two groups showed moderate and consistent improvement over time although the larger group (n = 1,380) began treatment with more PTSD symptoms and improved more quickly over time. The smallest group (n = 87) showed a substantially different trajectory, with almost no net change in symptom levels over the 24-month period. The groups also varied significantly in terms of their characteristics, with symptom severity and improvements over time reflecting greater comorbidity and younger age. The results have both research and clinical implications.

Chronic Disease↗
PubMed2005

Health costs following motor vehicle accidents: The role of posttraumatic stress disorder.

This pilot study examined whether posttraumatic stress disorder (PTSD) was associated with increased health costs following severe injury caused by motor vehicle accidents. Three groups of injury survivors were created from a larger sample--PTSD only, no-PTSD-low physical function, and no-PTSD--high physical function-and these groups were compared on health cost outcomes at 12 and 24 months. The presence of PTSD was associated with increased total health costs for both Year 1 and Year 2. However, PTSD, per se, did not independently contribute to total health costs. This study suggests that ongoing physical health problems must be considered in order to accurately assess the unique contribution that PTSD makes to health costs in the physically injured population.

Accidents, Traffic↗
PubMed2005

Imputing missing repeated measures data: how should we proceed?

OBJECTIVE: This paper compares six missing data methods that can be used for carrying out statistical tests on repeated measures data: listwise deletion, last value carried forward (LVCF), standardized score imputation, regression and two versions of a closest match method. METHOD: The efficacy of each was investigated under a variety of sample sizes and with differing levels of missingness. Randomly selected samples from a dataset (n = 804) were used to compare the methods using t-tests. Efficacy was defined as the closeness of the estimated t-values to the true t-values from the complete dataset. RESULTS: The results suggest a reliable and efficacious basis for imputation method for repeated measures data is to substitute a missing datum with a value from another individual who has the closest scores on the same variable measured at other timepoints, or the average value of four individuals who have the closest scores on the same variable at other timepoints. The LVCF and standardized score methods performed relatively poorly, which is of concern since these are often recommended. Listwise deletion was also an inefficient missing data method. CONCLUSIONS: Researchers should consider using closest match missing data imputation. Since listwise deletion performed poorly, is widely reported and is the default method in many statistical software packages, the findings have broad implications.

Alcoholism↗
PubMed2005

Imputing cross-sectional missing data: comparison of common techniques.

OBJECTIVE: Increasing awareness of how missing data affects the analysis of clinical and public health interventions has led to increasing numbers of missing data procedures. There is little advice regarding which procedures should be selected under different circumstances. This paper compares six popular procedures: listwise deletion, item mean substitution, person mean substitution at two levels, regression imputation and hot deck imputation. METHOD: Using a complete dataset, each was examined under a variety of sample sizes and differing levels of missing data. The criteria were the true t-values for the entire sample. RESULTS: The results suggest important differences. If missing data are from a scale where about half the items are present, hot deck imputation or person mean substitution are best. Because person mean substitution is computationally simpler, similar in its efficiency, advocated by other researchers and more likely to be an option on statistical software packages, it is the method of choice. If the missing data are from a scale where more than half the items are missing, or with single-item measures, then hot deck imputation is recommended. The findings also showed that listwise deletion and item mean substitution performed poorly. CONCLUSIONS: Person mean and hot deck imputation are preferred. Since listwise deletion and item mean substitution performed poorly, yet are the most widely reported methods, the findings have broad implications.

Anxiety↗
PubMed2005

Determinants of quality of life and role-related disability after injury: impact of acute psychological responses.

BACKGROUND: The factors that determine quality of life (QOL) and disability after traumatic injury are poorly understood. This study identified the unique contributions that characteristics about the injury/hospital admission and acute psychological adjustment make in determining 12-month role-related disability and QOL. METHODS: Consecutive admissions (n = 363) to a Level I trauma service were assessed just before discharge and followed up at 12 months. Structural equational modeling was used to examine the relationships between the acute factors and 12-month outcomes. RESULTS: Characteristics of the individual's injuries measured in the acute setting significantly predicted 12-month disability but only indirectly predicted 12-month QOL. An individual's acute psychological response directly predicted both the level of disability and QOL at 12 months. CONCLUSIONS: Both characteristics about an individual's injury and acute psychological responses play important roles in determining later QOL and role-related disability outcomes. Trauma care systems must consider both physical and psychological injury to offer effective and comprehensive healthcare management.

Adult↗
PubMed2005

Clinical presentations and treatment outcomes of peacekeeper veterans with PTSD: preliminary findings.

OBJECTIVE: Despite evidence of potential psychiatric sequelae following peacekeeping operations, no data have appeared on treatment outcome for this population. This study examined intake and treatment outcome data for a group of peacekeepers with posttraumatic stress disorder (PTSD). METHOD: Participants were 63 Australian Vietnam veterans and 66 Australian peacekeepers attending specialized PTSD treatment units. Measures of PTSD, depression, anxiety, alcohol use, and anger were obtained at intake and 3-month follow-up. RESULTS: PTSD scores were more severe for peacekeepers than Vietnam veterans at intake, primarily in reexperiencing symptoms. In terms of comorbidity, only anger was higher among peacekeepers. No differences were apparent in treatment outcome. Initial anger predicted change in PTSD severity for peacekeepers. CONCLUSIONS: The finding of differences between peacekeepers and Vietnam veterans in anger and reexperiencing symptoms, in addition to the attenuating role of anger on treatment outcome, suggests that modification to standard PTSD treatment models may be warranted for peacekeepers.

Adult↗
PubMed2004

Phase I trial of the proteasome inhibitor bortezomib in patients with advanced solid tumors with observations in androgen-independent prostate cancer.

PURPOSE: To determine the dose-limiting toxicity and maximum-tolerated dose of the proteasome inhibitor bortezomib administered intravenously weekly for 4 every 5 weeks; to determine the bortezomib pharmacokinetics and pharmacodynamics using plasma levels and an assay for 20S proteasome inhibition (PI) in whole blood; to correlate toxicity with bortezomib dose and degree of 20S PI; and to conduct a preliminary determination of the antitumor activity of bortezomib in patients with androgen independent prostate cancer (AIPCa). PATIENTS AND METHODS: Fifty-three patients (48 with AIPCa) received 128 cycles of bortezomib in doses ranging from 0.13 to 2.0 mg/m(2)/dose, utilizing a careful escalation scheme with a continuous reassessment method. Pharmacokinetic and pharmacodynamic studies were performed in 24 patients (at 1.45 to 2.0 mg/m(2)). RESULTS: A dose-related 20S PI was seen, with dose-limiting toxicity at 2.0 mg/m(2) (diarrhea, hypotension) occurring at an average 1-hour post-dose of >/= 75% 20S PI. Other side effects were fatigue, hypertension, constipation, nausea, and vomiting. No relationship was seen between body-surface area and bortezomib clearance over the narrow dose range tested. There was evidence of biologic activity (decline in serum prostate-specific antigen and interleukin-6 levels) at >/= 50% 20S PI. Two patients with AIPCa had prostate-specific antigen response and two patients had partial response in lymph nodes. CONCLUSION: The maximum-tolerated dose and recommended phase II dose of bortezomib in this schedule is 1.6 mg/m(2). Biologic activity (inhibition of nuclear factor-kappa B-related markers) and antitumor activity is seen in AIPCa at tolerated doses of bortezomib. This agent should be further explored with chemotherapy agents in advanced prostate cancer.

Adult↗
PubMed2004

A concise measure of anger in combat-related posttraumatic stress disorder.

There is a need for a brief specific measure of anger for use in assessment of posttraumatic mental health problems. One unpublished short scale is the Dimensions of Anger Reactions (DAR; R. Novaco, 1975). This study examined the psychometric properties of the DAR using intake and 12-month data for 192 Australian Vietnam veterans with combat-related PTSD. Results showed the DAR to be unidimensional, reliable, and sensitive to change over time, and removal of two items improved the scale's properties. The DAR measures anger disposition directed towards others. Assessment of convergent validity indicated that the DAR primarily measures Trait Anger. Results suggest that the DAR is a psychometrically strong measure, potentially useful for the evaluation of anger in PTSD.

Anger↗
PubMed2004

Stressors, burnout and social support: nurses in acute mental health settings.

AIMS: This paper reports a study which aims (1) to investigate and compare levels of stressors and burnout of qualified and unqualified nursing staff in acute mental health settings; (2) to examine the relationships between stressors and burnout and (3) to assess the impact of social support on burnout and stressor-burnout relationships. BACKGROUND: Several studies have noted that the work of mental health nurses can be highly stressful, but relatively few have focused specifically on staff working in acute inpatient settings. Although many of the pressures faced by this group are similar to those in other nursing specialties, a number of demands relate specifically to mental health settings, including the often intense nature of nurse-patient interaction and dealing with difficult and challenging patient behaviours on a regular basis. METHODS: A convenience sample of 93 nursing staff from 11 acute adult mental health wards completed the Mental Health Professionals Stress Scale, Maslach Burnout Inventory and House and Wells Social Support Scale. RESULTS: Lack of adequate staffing was the main stressor reported by qualified staff, while dealing with physically threatening, difficult or demanding patients was the most stressful aspect for unqualified staff. Qualified nurses reported significantly higher workload stress than unqualified staff. Approximately half of all nursing staff showed signs of high burnout in terms of emotional exhaustion. A variety of stressors were positively correlated with emotional exhaustion and depersonalization. Higher levels of support from co-workers were related to lower levels of emotional exhaustion. Higher stressor scores were associated with higher levels of depersonalization for staff reporting high levels of social support, but not for those reporting low levels of support (a reverse buffering effect). CONCLUSIONS: Qualified and unqualified nursing staff differed in terms of the prominence given to individual stressors in their work environment. The findings were consistent with the notion of burnout developing in response to job-related stressors. While staff support groups may be useful in alleviating feelings of burnout, the reverse buffering effect suggests that they should be structured in a way that minimizes negative communication and encourages staff to discuss their concerns in a constructive way.

Adult↗
PubMed2003

Advances in cardiopulmonary bypass circuitry.

PURPOSE OF REVIEW: The purpose of this review is to present developments in cardiopulmonary bypass circuitry, and to give the authors' opinions on the causes of the potentially harmful processes that are initiated by cardiopulmonary bypass, and how they may be attenuated. RECENT FINDINGS: Much of the recently published work investigates the effect of various forms of biocompatible circuitry, either heparin bonded, or polymer coated. The increasing number of patients having off-pump coronary surgery allows comparison of such patients with those that have had surgery using the various forms of cardiopulmonary bypass circuitry. SUMMARY: Recent developments of biocompatible circuits are promising in terms of their potential for reducing the perioperative inflammatory response. The use of such circuitry, however, is likely to be of benefit only when included as part of an overall strategy to control triggers of the inflammatory response during and after cardiac surgery, particularly in the high-risk patient.

Journal Article↗
PubMed2003

MMPI-2 based subgroups of veterans with combat-related PTSD: differential patterns of symptom change after treatment.

Considerable research has focused on the use of the MMPI to assess posttraumatic stress disorder (PTSD) through identification of mean profile configurations and the development of PTSD subscales. Little work, however, has addressed the heterogeneity of profiles evident in PTSD populations. This study investigated the MMPI-2 profiles of 158 Australian treatment-seeking Vietnam veterans with combat-related PTSD to identify distinct subgroups. Three robust subgroups were identified on the basis of their MMPI-2 profile and compared on PTSD and associated symptomatology. These subgroups consisted of a mild PTSD group with subclinical personality pathology, and two severe PTSD groups that differed in levels of personality disturbance and general psychopathology. Most notably, differences between these latter two groups occurred in the areas of externalization, alienation, and propensity for acting out. These groups were labeled as subclinical, trauma profile, and global. The groups demonstrated significant differences in the patterns of recovery after treatment. The subclinical group demonstrated little change after treatment. In contrast, the trauma profile and global groups both improved, although the trauma profile group demonstrated greater PTSD symptom reduction than the global group.

Australia↗
PubMed2002

Inpatient versus day hospital treatment for chronic, combat-related posttraumatic stress disorder: a naturalistic comparison.

This study adopted a quasi-experimental design to compare the treatment outcomes of inpatient-outpatient programs and day hospital programs for chronic, combat-related posttraumatic stress disorder. Data were drawn from 202 Vietnam veterans who had completed treatment at four programs across Australia. The veterans were assessed on a range of psychological and social variables at intake to the programs and followed up at 3 and 9 months after discharge. A significant main effect was found for time, with veterans from both program models demonstrating improvements that were maintained over the 9-month follow-up period. Group by time effects were not significant, which suggests that inpatient-outpatient programs are not more efficacious than the less expensive day hospital alternatives. In line with current mental health policy directions, the current study lends broad support to the recommendation that treatment services for veterans with posttraumatic stress disorder be delivered in the least restrictive environment.

Combat Disorders↗