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Biomedical subjects

A Burke

Publications and source records attributed to A Burke.

At least 19 recordsLinked to original sources
PubMed2003

Unusual complication of sternotomy: bone fragment induced right ventricular rupture after mitral valve replacement surgery.

Major surgical complications following open cardiac procedures via median sternotomy are infrequent but potentially devastating events. We report on a unique, fatal complication of median sternotomy. A 44-year-old woman underwent mitral valve replacement for endocarditis related to intravenous drug abuse. Twenty days after the surgery, she presented to the emergency department in acute distress, and died of cardiac tamponade soon after admission. Postmortem examination revealed a defect in the right ventricular wall caused by a bone fragment resulting from the median sternotomy.

Adult↗
PubMed2002

Lower cortisol levels in depressed patients with comorbid post-traumatic stress disorder.

Post-traumatic stress disorder (PTSD) is often comorbid with major depressive episodes (MDEs) and both conditions carry a higher rate of suicidal behavior. Hypothalamic-pituitary-adrenal (HPA) axis and serotonin abnormalities are associated with both conditions and suicidal behavior, but their inter-relation is not known. We determined cortisol response to placebo or fenfluramine in MDE, MDE and PTSD (MDE+PTSD), and healthy volunteers (HVs) and examined the relation of cortisol responses to suicidal behavior. A total of 58 medication-free patients with MDE (13 had MDE+PTSD) and 24 HVs were studied. They received placebo on the first day and fenfluramine on the second day. Cortisol levels were drawn before challenge and for 5 h thereafter. The MDE+PTSD group had the lowest plasma cortisol, the MDE group had the highest, and HVs had intermediate levels. There were no group differences in cortisol response to fenfluramine. Suicidal behavior, sex, and childhood history of abuse were not predictors of baseline or postchallenge plasma cortisol. Cortisol levels increased with age. This study finds elevated cortisol levels in MDE and is the first report of lower cortisol levels in MDE+PTSD. The findings underscore the impact of comorbidity of PTSD with MDE and highlight the importance of considering comorbidity in psychobiology.

Adult↗
PubMed2002

The effect of prostaglandin E(2) (PGE(2)) and long-chain polyunsaturated fatty acids (LC PUFA) on bone formation in piglets: a model for bone growth in nutritional investigation.

This research investigates the effects of exogenous prostaglandin E(2) (PGE(2)) treatment and arachidonic acid supplementation on the rate of growth in modelling bone of piglets. The piglet is a good model for the study of infant nutrition and bone growth. PGE(2) and long-chain polyunsaturated fatty acid (LC PUFA) supplementation, alone and in combination, are shown to have little or no effect on cortical bone thickness. Though exogenous PGE(2) supplementation and LC PUFA supplementation may both be effective in promoting bone growth and mass in adults, they do not appear to have the same positive effect on bone growth in infancy over a short term. A dynamic model for bone growth in piglets is proposed here for the first time. This research adds to our knowledge of the relationship between the dynamic histology of bone, the rate of osteogenesis, and the link between nutrition and bone growth.

Age Factors↗
PubMed2001

Relations between personality and depressive symptoms: a multimeasure study of dependency, autonomy, and related constructs.

Seventy-four patients seeking treatment for major depression completed four measures of dependent and autonomous personality and two measures of depressive symptomatology. Relationships among the personality measures were investigated by principal-components analysis, enabling systematic comparison of their composition. Relationships between personality components and symptom dimensions were examined to clarify specific associations that have been proposed but inconsistently obtained in previous research. Neither dependency nor autonomy were unitary constructs, and alternative measures had substantial differences in composition. Some support for symptom specificity was obtained. Dependency and autonomy have distinctive associations with depressive symptoms, but their correspondence to unitary personality dimensions and the equivalence of their alternative scales cannot be assumed.

Adult↗
PubMed2001

Gastrointestinal stromal tumors, intramural leiomyomas, and leiomyosarcomas in the rectum and anus: a clinicopathologic, immunohistochemical, and molecular genetic study of 144 cases.

Gastrointestinal stromal tumors (GISTs), the specific KIT-positive mesenchymal tumors of the gastrointestinal tract, have been sporadically reported in the rectum, but there are few clinicopathologic series. In this study we analyzed the clinicopathologic features of 133 anorectal GISTs, 3 intramural leiomyomas (LMs), and 8 leiomyosarcomas (LMSs) from the files of the Armed Forces Institute of Pathology and the Haartman Institute of the University of Helsinki. Ninety-six GISTs were documented as KIT-positive and three additional ones as CD34-positive. Thirty-four tumors were included by their histologic similarity to KIT- or CD34-positive cases. GIST-specific c-kit gene mutations, mostly in exon 11, were documented in 18 of 29 cases (62%). The GISTs occurred in adults with the age range of 17-90 years (median 60 years) with a significant male predominance (71%). The tumors ranged from small asymptomatic intramural nodules to large masses that bulged into pelvis causing pain, rectal bleeding, or obstruction. They were mostly highly cellular spindle cell tumors; four tumors had an epithelioid morphology. The tumors coexpressed CD34 and KIT and were rarely positive for smooth muscle actin or desmin and never for S-100 protein. Seventy percent of patients with tumors >5 cm with more than 5 mitoses/50 high power fields (HPF) (n = 31) died of disease, whereas only one tumor <2 cm with <5 mitoses/50 HPF (n = 21) recurred and none caused death. Long latency was common between primary operation and recurrences and metastases; either one occurred in 60 of 111 patients with follow-up (54%). Distant metastases were in the liver, bones, and lungs. Three benign actin- and desmin-positive and KIT-negative intramural LMs, similar to those seen in the esophagus, were identified. There were eight LMSs, six of which formed a polypoid intraluminal mass and were actin-positive and KIT-negative. Despite high mitotic counts, only one LMS patient died of disease. A great majority of rectal smooth muscle and stromal tumors are GISTs, which have a spectrum from minimal indolent tumors to overt sarcomas. Intramural LMs are exceptional, and true LMSs are rare, and similar to colonic ones, often present as intraluminal polypoid masses that appear to have a better prognosis than GISTs with similar mitotic rates.

Adolescent↗
PubMed2001

Determining landscape function and ecosystem dynamics: contribution to ecological restoration in the southern Namib desert.

The southern Namib is characterized by high biodiversity, changes in winter and summer rainfall, extreme climatic conditions and associated geomorphologic processes, a paucity of ecological knowledge, and multiple environmental threats posed by conflicting development options. With the long-term view to establish a research initiative focussing on restoration ecology in the southern Namib Desert, this article provides a review of current ecological knowledge and proposes potential research priorities. The aims of a research initiative would be two-fold. On the academic side, understanding processes operating at different scales will be critical to develop methods of ecological restoration suitable for southern Namib ecosystems. On the practical side, the development of appropriate methods will focus on facilitating ecological processes such as restoration of biologically active substrate, natural succession, and concentration of limited resources. The function of landscapes, plant-soil interface, soil-, vegetation- and plant population dynamics will likely provide some of the answers for ecological restoration.

Desert Climate↗
PubMed2001

Anomalous origin of 4 coronary ostia from the right sinus of Valsalva in a patient with hypertrophic cardiomyopathy.

Anomalous origin of 4 separate coronary ostia from a single coronary sinus has rarely been reported. We report what is to our knowledge a previously undescribed variation characterized by the left anterior descending, left ramus, left circumflex, and right coronary arteries originating from separate ostia in the right sinus of Valsalva. In addition, the autopsy disclosed features of hypertrophic cardiomyopathy, rarely associated with congenital coronary anomalies.

Cardiomyopathy, Hypertrophic↗
PubMed2001

The effect of prostaglandin E2 and arachidonic acid on dentinogenesis in pigs.

The rate of dentinogenesis for the pig is quantified and the effects of dietary arachidonic acid supplementation and/or exogenous prostaglandin on dentine formation are defined. Thirty-six pigs were randomised to four groups, receiving either standard or supplemented formula and either prostaglandin E2 or placebo injections for fifteen days. Double tetracycline banding is used to measure rate of growth in the teeth. The average rate of dentinogenesis for all the study animals is 17.96 microm/day. Results show that the rate of dentinogenesis is not significantly affected by the interaction of hormone and dietary supplementation.

Animals↗
PubMed2000

Association between alpha-tocopherol, gamma-tocopherol, selenium, and subsequent prostate cancer.

BACKGROUND: Selenium and alpha-tocopherol, the major form of vitamin E in supplements, appear to have a protective effect against prostate cancer. However, little attention has been paid to the possible role of gamma-tocopherol, a major component of vitamin E in the U.S. diet and the second most common tocopherol in human serum. A nested case-control study was conducted to examine the associations of alpha-tocopherol, gamma-tocopherol, and selenium with incident prostate cancer. METHODS: In 1989, a total of 10,456 male residents of Washington County, MD, donated blood for a specimen bank. A total of 117 of 145 men who developed prostate cancer and 233 matched control subjects had toenail and plasma samples available for assays of selenium, alpha-tocopherol, and gamma-tocopherol. The association between the micronutrient concentrations and the development of prostate cancer was assessed by conditional logistic regression analysis. All statistical tests were two-sided. RESULTS: The risk of prostate cancer declined, but not linearly, with increasing concentrations of alpha-tocopherol (odds ratio (highest versus lowest fifth) = 0.65; 95% confidence interval = 0.32--1.32; P(trend) =.28). For gamma-tocopherol, men in the highest fifth of the distribution had a fivefold reduction in the risk of developing prostate cancer than men in the lowest fifth (P:(trend) =.002). The association between selenium and prostate cancer risk was in the protective direction with individuals in the top four fifths of the distribution having a reduced risk of prostate cancer compared with individuals in the bottom fifth (P(trend) =.27). Statistically significant protective associations for high levels of selenium and alpha-tocopherol were observed only when gamma-tocopherol concentrations were high. CONCLUSIONS: The use of combined alpha- and gamma- tocopherol supplements should be considered in upcoming prostate cancer prevention trials, given the observed interaction between alpha-tocopherol, gamma-tocopherol, and selenium.

Aged↗
PubMed2000

Substantial correlation between HIV type 1 drug-associated resistance mutations in plasma and peripheral blood mononuclear cells in treatment-experienced patients.

The correlation of detectable HIV-1 drug resistance mutations in plasma and PBMCs in patients extensively treated with all antiretroviral drug classes has not been fully elucidated. The detection of mutations in PBMCs may reveal resistant HIV-1 associated with past therapies. In addition, these measures in PBMCs may have a practical value when plasma virus is at low levels that are difficult to detect with current assays. The reverse transcriptase (RT) and protease (P) genes were analyzed for drug resistance, using an in-house method carried out on 36 paired samples of plasma and PBMCs from 12 treatment-experienced patients in order to investigate resistance in the two compartments. When viruses in plasma and PBMCs were analyzed by patient, the mean of the Cohen kappa values was 0.728 (substantial agreement). When viruses were analyzed by codon the mean of the Cohen kappa values was 0.715 (substantial agreement). Baseline samples were concordant at 280 of 288 (97%) codons analyzed. This study shows that a minority of mutations associated with previous therapy can be detected in PBMCs and not in plasma. Overall, mutations in plasma and PBMCs showed a substantial correlation in extensively treated patients, suggesting that either compartment is suitable for the detection of mutations as a virological guide for clinical care.

Anti-HIV Agents↗
PubMed2000

Reduction in human immunodeficiency virus type 1 mutations associated with drug resistance after initiating new therapeutic regimens in pretreated patients.

The objective of this study was to investigate the effect of initiating a salvage-therapy regimen on resistant viruses in heavily treated patients infected with human immunodeficiency virus type 1 (HIV-1). Nineteen patients receiving multiple antiretroviral drugs were tested for HIV-1 mutations associated with drug resistance by using an in-house method at baseline and at weeks 2, 4, and 8 of the salvage-therapy regimen. For the majority of mutations analyzed, the mean number of detectable mutations at baseline was significantly higher than the mean at weeks 2, 4, and 8 of salvage therapy. Introducing new and more potent therapy reduces the number of detectable drug resistance-associated mutations within 8 weeks, and no evidence was found that the new therapy promoted the emergence of novel mutations.

Anti-HIV Agents↗
PubMed2000

Specific analysis in plasma and urine of 2,3-dinor-5, 6-dihydro-isoprostane F(2alpha)-III, a metabolite of isoprostane F(2alpha)-III and an oxidation product of gamma-linolenic acid.

F(2)-isoprostanes (iPs) are free radical-catalyzed isomers of prostaglandin F(2alpha). Circulating and urinary iPs have been used as indices of lipid peroxidation in vivo. Utilizing an (18)O-labeled homologous internal standard, we developed a gas chromatography/mass spectrometry assay for the 2,3-dinor-5,6-dihydro (dinor-dihydro) metabolite of iPF(2alpha)-III. Although urinary excretion of iPF(2alpha)-III reflects systemic lipid peroxidation, the metabolite is more abundant (median of 877 (range of 351-1831) versus 174 (range of 56-321) pg/mg of creatinine; p < 0.01) than the parent iP in urine and can be measured in plasma. Metabolite analysis may be preferable in plasma due to the abundance of arachidonic acid as a source of ex vivo lipid peroxidation. Also, iPF(2alpha)-III may be formed in blood samples in a cyclooxygenase-dependent manner by platelets ex vivo. By contrast, the metabolite is not formed by aggregated platelets (0.71 +/- 0.08 versus 0.65 +/- 0.09 pg/ml). Although the metabolite/parent ratio is altered in cirrhosis, urinary dinor-dihydro-iPF(2alpha)-III is elevated and increases further during reperfusion following orthoptic liver transplantation. In addition to its formation as an iPF(2) metabolite, analysis of gamma-linolenic acid autooxidation products and the compound present in freeze-thawed plasma suggests that gamma-linolenic acid may also be an important source of dinor-dihydro-iPF(2alpha)-III.

Adult↗
PubMed2000

How to accomplish organization-wide competency and education.

To achieve high-quality, low-cost outcomes, all employees must be competent in their fields. Ensure one high standard for the entire organization with these seven steps to plan an organization-wide education and competency program.

Clinical Competence↗
PubMed2000

Thermostabilization of proteins by diglycerol phosphate, a new compatible solute from the hyperthermophile Archaeoglobus fulgidus.

Diglycerol phosphate accumulates under salt stress in the archaeon Archaeoglobus fulgidus (L. O. Martins, R. Huber, H. Huber, K. O. Stetter, M. S. da Costa, and H. Santos, Appl. Environ. Microbiol. 63:896-902, 1997). This solute was purified after extraction from the cell biomass. In addition, the optically active and the optically inactive (racemic) forms of the compound were synthesized, and the ability of the solute to act as a protecting agent against heating was tested on several proteins derived from mesophilic or hyperthermophilic sources. Diglycerol phosphate exerted a considerable stabilizing effect against heat inactivation of rabbit muscle lactate dehydrogenase, baker's yeast alcohol dehydrogenase, and Thermococcus litoralis glutamate dehydrogenase. Highly homologous and structurally well-characterized rubredoxins from Desulfovibrio gigas, Desulfovibrio desulfuricans (ATCC 27774), and Clostridium pasteurianum were also examined for their thermal stabilities in the presence or absence of diglycerol phosphate, glycerol, and inorganic phosphate. These proteins showed different intrinsic thermostabilities, with half-lives in the range of 30 to 100 min. Diglycerol phosphate exerted a strong protecting effect, with approximately a fourfold increase in the half-lives for the loss of the visible spectra of D. gigas and C. pasteurianum rubredoxins. In contrast, the stability of D. desulfuricans rubredoxin was not affected. These different behaviors are discussed in the light of the known structural features of rubredoxins. The data show that diglycerol phosphate is a potentially useful protein stabilizer in biotechnological applications.

Alcohol Dehydrogenase↗
PubMed2000

Effect of regulated expression of human cyclooxygenase isoforms on eicosanoid and isoeicosanoid production in inflammation.

To examine the role of cyclooxygenase (COX) isozymes in prostaglandin formation and oxidant stress in inflammation, we administered to volunteer subjects placebo or bolus injections of lipopolysaccharide (LPS), which caused a dose-dependent increase in temperature, heart rate, and plasma cortisol. LPS caused also dose-dependent elevations in urinary excretion of 2,3-dinor 6-keto PGF(1alpha) (PGI-M) and 11-dehydro thromboxane B(2) (Tx-M). Platelet COX-1 inhibition by chronic administration of low-dose aspirin before LPS did not alter the symptomatic and febrile responses to LPS, but the increment in urinary PGI-M and Tx-M were both partially depressed. Pretreatment with ibuprofen, a nonspecific COX inhibitor, attenuated the febrile and systemic response to LPS and inhibited prostanoid biosynthesis. Both celecoxib, a selective COX-2 inhibitor, and ibuprofen attenuated the pyrexial, but not the chronotropic, response to LPS. Experimental endotoxemia caused differential expression of the COX isozymes in monocytes and polymorphonuclear leucocytes ex vivo. LPS also increased urinary iPF(2alpha)-III, iPF(2alpha)-VI, and 8,12-iso-iPF(2alpha)-VI, isoprostane (iP) indices of lipid peroxidation, and none of the drugs blunted this response. These studies indicate that (a) although COX-2 predominates, both COX isozymes are induced and contribute to the prostaglandin response to LPS in humans; (b) COX activation contributes undetectably to lipid peroxidation induced by LPS; and (c) COX-2, but not COX-1, contributes to the constitutional response to LPS in humans.

Adult↗
PubMed2000

Before the fire.

Explore the source record for details and available documents.

Facility Design and Construction↗