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Biomedical subjects

A Stewart

Publications and source records attributed to A Stewart.

At least 145 records · Page 8Linked to original sources
PubMed1997

Posttraumatic stress disorder and functioning and quality of life outcomes in a nationally representative sample of male Vietnam veterans.

OBJECTIVE: Although posttraumatic stress disorder (PTSD) is a highly prevalent and often chronic condition, the relationship between PTSD and functioning and quality of life remains incompletely understood. METHOD: The authors undertook an archival analysis of data from the National Vietnam Veterans Readjustment Study. The study subjects consisted of the nationally representative sample of male Vietnam veterans who participated in the National Vietnam Veterans Readjustment Study. The authors estimated PTSD at the time of the interview with the Mississippi Scale for Combat-Related Posttraumatic Stress Disorder. They examined the following outcomes: diminished well-being, physical limitations, bed day in the past 2 weeks, compromised physical health status, currently not working, and perpetration of violence. Logistic models were used to determine the association between PTSD and outcome; adjustment was made for demographic characteristics and comorbid psychiatric and other medical conditions. RESULTS: The risks of poorer outcome were significantly higher in subjects with PTSD than in subjects without PTSD in five of the six domains. For the outcome domains of physical limitations, not working, compromised physical health, and diminished well-being, these significantly higher risks persisted even in the most conservative logistic models that removed the shared effects of comorbid psychiatric and other medical disorders. CONCLUSIONS: The suffering associated with combat related-PTSD extends beyond the signs and symptoms of the disorder to broader areas of functional and social morbidity. The significantly higher risk of impaired functioning and diminished quality of life uniquely attributable to PTSD suggests that PTSD may well be the core problem in this group of difficult to treat and multiply afflicted patients.

Combat Disorders↗
PubMed1997

Altered activation of the L-arginine nitric oxide pathway during and after cardiopulmonary bypass.

The serum concentrations of nitrogen oxides, the stable metabolites of nitric oxide, were measured in 61 children during and after cardiopulmonary bypass (CPB) for surgery of congenital heart disease. Overall, there was a small reduction in serum nitrogen oxide concentrations during CPB, from a median of 27.5 (interquartile range 16.6-55.7) to 26.4 (15.3-40.6) mumol/l, followed by an increase in the following 24 h to 33.1 (21.3-46.7) mumol/l. The largest postoperative increases in nitrogen oxides occurred in children who developed renal impairment, or were treated with nitrovasodilators. There was no relationship between changes in serum nitrogen oxides intraoperatively and early changes in pulmonary vascular resistance, and a weak positive relationship between changes in serum nitrogen oxides and early postoperative changes in cardiac index (r2 = 0.09, p = 0.04). We found no evidence for increased activation of the L-arginine nitric oxide pathway during CPB; and the reduction in nitric oxide metabolites that occurred during CPB were of doubtful significance to pulmonary or systemic haemodynamic changes in the postoperative period.

Arginine↗
PubMed1997

A-bomb data: detection of bias in the Life Span Study cohort.

By drawing a distinction between A-bomb survivors with and without bomb-related injuries, it was possible to see that instead of the Life Span Study (LSS) cohort being a normal, homogenous population, there were significant differences between survivors with and without multiple injuries, and that these differences occurred largely among survivors who were under 10 or over 50 years of age when exposed. There also was a concentration of A-bomb-related injuries among survivors who eventually developed leukemia. So it is possible that deaths before 1950 had left the LSS cohort permanently biased in favor of persons who had high levels of resistance to all (early and late) effects of radiation. It is also possible that the high proportion of leukemia cases among the deaths of A-bomb survivors from 1950 to 1970 were because the radiation caused an initial leukocytosis followed by loss of immunologic competence.

Adolescent↗
PubMed1997

Risk estimation for badge-monitored radiation workers.

In estimating the cancer mortality risk for radiation workers it is conventional to use data obtained from the populations exposed to radiation as a result of the atomic bomb blast in Hiroshima and Nagasaki. This A-bomb experience resulted in relatively high doses of radiation and short periods of exposure. The availability of systematic analyses of the mortality of workers at the Hanford plant (Washington state) provides a more realistic basis for individual risk estimates. We present the data for three functions that in combination provide useful guidelines for occupational cancer mortality risk. These functions are a relationship between age at exposure, latency between exposure and death, and a dose-response function. Although other estimates of such functions are possible using different populations and assumptions, we offer these functions as guidelines for individual cancer risk evaluation based on our analyses of the Hanford data.

Adolescent↗
PubMed1997

Evaluation of the antiinflammatory activity of a dual cyclooxygenase-2 selective/5-lipoxygenase inhibitor, RWJ 63556, in a canine model of inflammation.

Sterile perforated polyethylene spheres (wiffle golf balls) were implanted s.c. in beagle dogs. A local inflammatory reaction was elicited within the spheres by injecting carrageenan. Changes in leukocyte count, prostaglandin E2, thromboxane B2 and leukotriene B4 levels were monitored in fluid samples collected over a 24-hr period. Blood samples were also collected at various time points and analyzed for prostaglandin E2 and leukotriene B4 production after ex vivo calcium ionophore treatment. Effects of standard antiinflammatory agents (aspirin, indomethacin, dexamethasone, tenidap and zileuton) and newer cyclooxygenase-2 (COX-2) selective agents (nimesulide, nabumetone and SC-58125) were determined after oral administration. Ex vivo inhibition of cyclooxygenase product synthesis (prostaglandin E2, thromboxane B2) in whole blood was used as an indicator of activity for the constitutive COX-1 isoform, although inhibition of the synthesis of these mediators in the chamber exudate during an inflammatory process is believed to represent COX-2 inhibition. Treatment effects on leukotriene B4 production were also determined both ex vivo in whole blood and in the fluid. All of the compounds tested, except aspirin, inhibited leukocyte infiltration into the fluid exudate. Inhibitors that exert their effects on both isozymes of cyclooxygenase attenuate production of cyclooxygenase metabolites in both the inflammatory exudate and in peripheral blood ex vivo, although COX-2 selective inhibitors only demonstrated activity in the exudate. A 5-lipoxygenase inhibitor (zileuton), a corticosteroid (dexamethasone) and a dual COX-2 selective/5-lipoxygenase inhibitor (RWJ 63556) had similar profiles in that they all inhibited cell infiltration and eicosanoid production in the fluid and also attenuated leukotriene B4 production in both the fluid and blood.

Animals↗
PubMed1997

Post-traumatic stress disorder and functioning and quality of life outcomes in female Vietnam veterans.

OBJECTIVE: This investigation assessed whether current post-traumatic stress disorder (PTSD) was associated with impaired functioning in a nationally representative sample of female Vietnam veterans. METHODS: Logistic models were used to determine the association between PTSD and outcome while adjusting for demographic characteristics and medical and psychiatric co-morbidities. RESULTS: PTSD was associated with significantly elevated odds of poorer functioning in five of the six outcome domains; only the association between perpetration of violence in the past year and PTSD did not achieve statistical significance. After adjusting for demographics and medical and psychiatric co-morbidities, PTSD remained associated with significantly elevated odds of bed days, poorer physical health, and currently not working. CONCLUSIONS: Among female Vietnam veterans PTSD is associated with a broad profile of functional impairment. The significantly increased odds of impaired functioning and diminished quality of life suggest that PTSD may be the core problem of the set of problems afflicting female Vietnam veterans.

Activities of Daily Living↗
PubMed1997

Visual impairment in Northern Ireland.

Statistics on the registration of blind and partially-sighted patients in Northern Ireland underestimate the true extent of visual impairment within our community. In comparison to other UK regions, where between 0.53% and 0.59% of the population avail of blind or partial sight registration, only 0.35% of residents in Northern Ireland appear on the respective registers. Most patients on the combined registers are in the older age groups and many also suffer from other disabilities. Regional discrepancies may be attributed to a combination of factors including: patient attitudes to the registration process, medical attitudes to registration and local anomalies in the way in which social services departments both record and present annual registration returns. Better liaison is necessary between the community, hospital and voluntary sector providers to improve identification and support services for the visually impaired in the future.

Adolescent↗
PubMed1996

Trends and determinants of blood pressure in Auckland, New Zealand 1982-94.

AIM: To describe blood pressure trends in Auckland, New Zealand from 1982 to 1994 and assess possible explanations for the trends. METHODS: Three cross sectional surveys of cardiovascular risk factors were undertaken in 1982, 1986-8 and 1993-4, with a total of 3806 European men and women aged 35-64 years randomly selected from Auckland electoral rolls. RESULTS: Mean systolic blood pressure fell in males from 132.2 mmHg in 1982 to 126.3 mmHg in 1993-4, and in females from 125.9 mmHg in 1982 to 121.7 mmHg in 1993-4. Both male and female diastolic mean blood pressure decreased more than 6 mmHg over the 12 years. The prevalence of antihypertensive drug use fell over the 12 year period. Regression analysis revealed a positive association between blood pressure and blood lipids. Body mass index (BMI) was also positively related to blood pressure while cigarette smoking was inversely related. However, concurrent trends in blood lipids, BMI and cigarette smoking could account for less than 6% of the average decline in systolic blood pressure over the 12 year period. CONCLUSION: There has been a substantial fall in mean blood pressure levels in Auckland adults aged 35-64 years which appears to be due to a shift in the general population blood pressure. The reduction in blood pressure is not explained by changes in pharmaceutical interventions and only a small part of the decline can be explained by concurrent trends in cardiovascular risk factors.

Adult↗
PubMed1996

Relations of changes in coronary disease rates and changes in risk factor levels: methodological issues and a practical example.

One of the main hypotheses of the World Health Organization (WHO) MONICA Project is that trends in the major coronary disease risk factors are related to trends in rates of fatal and non-fatal coronary disease events. The units of study are populations rather than individuals. The WHO MONICA Project involves continuous monitoring of all coronary disease events in the populations over a 10-year period and periodic risk factor surveys in random samples of the same populations. Estimation of associations between average annual changes in mortality and risk factor levels is illustrated with the use of data from a subset of MONICA centers. Crude estimates of regression coefficients are compared with estimates obtained by weighting for standard errors in both the outcome and explanatory variables. The results show that the strength of association may be either underestimated or overestimated if these errors are not taken into account.

Adult↗
PubMed1996

Stimulation of actin stress fibre formation mediated by activation of phospholipase D.

BACKGROUND: Agonist-stimulated phospholipase D (PLD) catalyzes the hydrolysis of phosphatidylcholine, generating the putative messenger phosphatidate (PA). Proposed functions for PA, and hence for PLD, include kinase activation, the regulation of small molecular weight GTP-binding proteins, actin polymerization and secretion. It has not been possible to define a physiological function for PLD activation as it is generally stimulated together with other signalling pathways, such as those involving phospholipases A2 and C, phosphatidylinositide (PI) 3-kinase and the p21(ras)/mitogen-activated protein (MAP) kinase cascade. RESULTS: We report that, in porcine aortic endothelial (PAE) cells, lysophosphatidic acid (LPA) stimulated PLD activity and rapidly generated PA in the absence of other phospholipase, PI 3-kinase or MAP kinase activities. PLD activation was controlled by a tyrosine kinase-regulated pathway. LPA also stimulated actin stress fibre formation, but was inhibited by butan-1-ol; the alcohol also reduced the accumulation of PA. The addition of PA to cells did not stimulate PLD activity, but did cause stress fibre formation in a manner that was insensitive to butan-1-ol. Stimulation of stress fibre formation by LPA and PA was sensitive to genistein, and was inhibited by micro-injection of the Rho-inhibiting C3 exotoxin into PAE cells. CONCLUSIONS: This study provides the first clear demonstration of a physiological role for PLD activity. In PAE cells, the stimulation of actin stress fibre formation was a consequence of PA generation and, therefore, PLD activation. The results suggest that PA generation is upstream of Rho activation, and imply a role for PLD in the regulation of Rho-mediated pathways.

Actins↗
PubMed1996

Antigen receptors on immature, but not mature, B and T cells are coupled to cytosolic phospholipase A2 activation: expression and activation of cytosolic phospholipase A2 correlate with lymphocyte maturation.

The Ag receptors on mature B and T cells are not coupled to the activation of cytosolic phospholipase A2 (cPLA2) and arachidonic acid release. Moreover, phorbol esters such as PMA, which can activate cPLA2 via mitogen-activated protein (MAP) kinase in most cell types, also failed to induce the release of arachidonate from mature cells, suggesting that the cPLA2 pathway may not be functional in mature lymphocytes. Interestingly, Western blot analysis revealed that cPLA2, which had previously been thought to be expressed ubiquitously, is not expressed in mature B or T cells and that cytosolic phospholipase A2 expression could not be up-regulated in lymphocytes following culture with a range of cytokines most likely to be involved in an immune response such as IL-1 alpha, IL-3, or TNF-alpha. In contrast, cPLA2 was shown to be expressed and activated in thymocytes and immature B cells under conditions in which ligation of the Ag receptors led to growth arrest and/or apoptosis. Taken together, these data suggest that cPLA2 does not play a role in Ag receptor-mediated lymphocyte activation, but may be involved in the molecular mechanisms underlying lymphocyte maturation and/or self tolerance by clonal deletion.

Animals↗
PubMed1996

Ethnic differences and recent trends in coronary heart disease incidence in New Zealand.

AIMS: This study compares recent coronary heart disease morbidity and mortality rates and ten year trends for Maori, Pacific Islands people and Europeans living in New Zealand. METHODS: Fatal coronary heart disease rates (mortality) and nonfatal hospitalisation rates for myocardial infarctions (morbidity) from 1983-92 were assessed and compared for males and females in each ethnic group, aged 35 to 64 years, using data from the Auckland Region Coronary or Stroke Study (ARCOS), a community-based coronary heart disease surveillance programme. RESULTS: The recent 1990-2 mean coronary heart disease mortality rate for Maori men (232/100 000) was almost double the rate for Pacific Islands men (135/100 000 p=0.008) and more than double the rate for European men (103/100 000 p=0.001). Maori women had a three-fold higher mean mortality rate (85/100 000) than European women (25/100 000 p=0.02). The morality rate for Pacific Islands women (42/100 000) was midway between the other ethnic groups. Over the decade 1983-92 coronary heart disease mortality rates have decreased significantly by approximately 5% per year for European men and women. Rates for Maori and Pacific Islands people also appear to have fallen although the precision of these estimates are low. Morbidity rates in 1990-2 were similar among men in all three ethnic groups. Among women, morbidity was approximately half the male rates and there were no clear differences between the ethnic groups. Between 1983 and 1992 morbidity rates declined significantly for European men (p=0.008) and women (p=0.02) by approximately 5% per year. Among Maori and Pacific Islands people the trends were variable. CONCLUSION: Maori men and women continue to experience more than double the coronary heart disease mortality rates than Europeans. Mortality rates for Pacific Islands people are intermediate between Maori and European. Both coronary heart disease mortality and morbidity rates are declining in Europeans; there appears to have been a decline in coronary heart disease mortality for Maori and Pacific Islands groups but not in morbidity rates which may have increased. Given the trend towards a decline in coronary heart disease mortality for Maori and Pacific Islands people, the most likely explanation for the apparent increase in morbidity is improved access to secondary health care services and greater awareness of coronary health disease symptoms.

Adult↗
PubMed1996

The value of clinical judgment in the diagnosis of nosocomial pneumonia.

BACKGROUND: Nosocomial pneumonia presents a diagnostic and therapeutic challenge in the care of critically ill patients. The present study was designed to determine as closely as possible the occurrence of nosocomial pneumonia in surgical intensive care unit (ICU) patients using clinical, radiographic, and bacteriological parameters in a prospective concurrent fashion. METHODS: This clinical study enrolled all surgical, trauma, and neurosurgical patients admitted to a surgical ICU over a 13-month period. Routine surveillance was used to identify those patients suspected of developing nosocomial pneumonia. Numerous clinical parameters concerning ventilatory support, acute lung injury, organ dysfunction, nutrition, and length of stays were used to identify factors disposing to development of pneumonia. Univariate and multivariate analyses were used for this purpose. Patients thought to have pneumonia were then followed concurrently to determine, as closely as possible, whether pneumonia was present by serial examination of clinical, bacteriologic, and radiographic data. Those "validated" by this process were then compared to those "nonvalidated" to see if any distinction could be made. RESULTS: Of the 352 patients enrolled, 46 (13%) were initially labeled as having developed nosocomial pneumonia when compared to the 306 patients without pneumonia. Univariate analysis demonstrated a greater need for intubation and mechanical ventilation, longer mechanical ventilation, more acute lung injury, longer ICU and hospital stays, poorer nutrition, and higher mortality (17% versus 5%, P < 0.01). Multivariate analysis demonstrated only length of ICU stay and length of intubation/mechanical ventilation as longer in the pneumonia group. On further concurrent review, 23 of 46 patients were validated as having pneumonia while the rest were felt not to have pneumonia. When the two groups were compared, only asymmetric and segmental radiographic infiltrates distinguished validated from nonvalidated pneumonia patients and all other clinical parameters, including mortality and length of stay, were similar. CONCLUSION: Nosocomial pneumonia was initially suspected in 13% of this ICU population. Numerous clinical parameters clearly distinguished these pneumonia patients from others and they suffered a substantially higher mortality. However, within this pneumonia group, only half of the patients could be validated as truly having pneumonia using available clinical parameters. Nevertheless, those validated were indistinguishable in their clinical behavior from those who were not. This calls into question the need for elaborate and sometimes expensive investigations for diagnosis of nosocomial pneumonia.

Adult↗
PubMed1996

Acquired anterior open bite and facial arthromyalgia: possible aetiology.

The development of an anterior open bite in four patients with facial arthromyalgia is described. There were radiological signs of condylar erosion in three of these cases. It is proposed that the pre-senile destructive arthropathy of the temporomandibular joint, seen in a small proportion of patients with facial arthromyalgia, results from lysis of articular cartilage and bone, secondary to an inflammatory process initiated by the local release of neuropeptides. Occlusal changes, including anterior open bite, may occur if the destructive arthropathy is severe and outstrips dentoalveolar compensation.

Adolescent↗
PubMed1996

Three-dimensional nasal changes following maxillary advancement in cleft patients.

Three-dimensional laser surface scanning of the face was performed before and after Le Fort I maxillary advancement in 24 patients with replaced clefts of the lip and palate. The surgery resulted in advancement of the upper lip and para-alar tissues and an increase in the relative prominence of the nose within the face. These changes were produced at the expense of an increase in nasal width and a reduction in nasal tip protrusion. The changes in nasal morphology showed significant variation among patients.

Adult↗
PubMed1996

Generic prescribing for epilepsy. Is it safe?

Generic prescribing for epilepsy remains controversial. This study aimed to ascertain if a change occurred in the incidence of seizures or side-effects when a different pharmaceutical manufacturer's version of the same antiepileptic drug was taken (a 'switch'). Forty general practices with a list size of 350 168 were recruited. They identified 2285 people being treated for epilepsy with either carbamazepine, phenytoin or sodium valproate. A questionnaire was sent to the people with epilepsy. Those who recalled taking a different pharmaceutical manufacturer's supply of the same antiepileptic drug over the last 2 years were interviewed by their practice if they reported a problem with the control of their epilepsy after a 'switch'. One thousand, three hundred and thirty-three (58.8%) people with epilepsy responded: 251 (18.7%) had experienced a 'switch', 27 (10.8%) reported 'validated' problems; 25 (9.9%) reported unproven problems; 22 (8.8%) reported problems, but follow-up was incomplete; 177 (70.5%) reported no problems. This study suggests that money saved by generic prescribing is outweighed by negative health gain for the person with epilepsy, increased work in general practice, and increased social costs.

Adult↗