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Biomedical subjects

R Hunt

Publications and source records attributed to R Hunt.

At least 37 records · Page 2Linked to original sources
PubMed1997

Increased immunolocalization of paraoxonase, clusterin, and apolipoprotein A-I in the human artery wall with the progression of atherosclerosis.

Using immunolocalization techniques, we have shown that paraoxonase (Pon), clusterin, and apolipoprotein (apo) A-I accumulate in the artery wall during the development of atherosclerosis. In normal aortas (n = 6) there were low levels of extracellular Pon, clusterin, and apoA-I, immunoreactivity. The cytoplasm of smooth muscle cells in the media showed granular positivity for both Pon and apoA-I, indicating that these proteins were undergoing lysosomal degradation. This activity was also indicated by the presence of both intact and degradation products of Pon in smooth muscle cells as shown by Western blotting. With the progression of disease from fatty streaks (n = 3) to advanced atherosclerosis (n = 8) there was an increase in Pon, apoA-I, and clusterin immunoreactivity, indicating the increasing presence of these proteins with disease progression. These proteins are the components of a specific HDL subspecies that has been implicated in the prevention of peroxidative damage to phospholipids in LDL and membranes. The increase in Pon, clusterin, and apoA-I during the development of atherosclerosis may therefore represent a protective response to the oxidative stress associated with the development of atherosclerosis.

Adult↗
PubMed1996

Outcome of patients discharged from a coronary care unit with a diagnosis of "chest pain not yet diagnosed".

OBJECTIVE: To determine the outcome and 3-year mortality rate among patients discharged from a coronary care unit (CCU) with a diagnosis of "chest pain not yet diagnosed." DESIGN: Prospective observational cohort study. SETTING: CCU in a university teaching hospital. PATIENTS: All 158 eligible patients discharged from the CCU between August 1986 and December 1988. Of them, 27 refused to participate and 31 did not meet the inclusion criteria because of significant co-morbidity or transportation difficulties. INTERVENTIONS: Evaluation with maximal and thallium exercise stress testing and four major gastrointestinal (GI) investigations: 24-hour intraesophageal pH monitoring, upper GI endoscopy with biopsy, esophageal motility studies and an upper GI barium series. OUTCOME MEASURES: Results of investigations and incidence of recurrent chest pain, CCU readmission, coronary angiography, coronary artery bypass surgery, myocardial infarction and death at 6, 12, 24 and 36 months after the index visit. RESULTS: Of the patients enrolled in the study 79% (79/100) had a normal exercise thallium stress test result, 74% (68/92) had an abnormal result from the 24-hour pH monitoring, 87% (82/94) had abnormal endoscopic results, 90% (84/93) had abnormal manometric results, and 89% (83/93) had signs of reflux with the barium series. At 3 years 50 patients had recurrent chest pain and 3 underwent coronary artery bypass surgery. Three patients died over the 3 years, all of noncardiac causes. CONCLUSION: Many patients discharged from the CCU with a diagnosis of chest pain not yet diagnosed have a high incidence of esophageal disorders and a very low 3-year mortality rate. More research into the early and effective identification and management of patients with such a diagnosis is needed.

Adult↗
PubMed1996

Myocardial contrast echocardiography: reliable, safe, and efficacious myocardial perfusion assessment after intravenous injections of a new echocardiographic contrast agent.

Reliable and reproducible myocardial opacification after intravenous administration of echocardiographic contrast agents has remained elusive. This study was performed to determine whether a new agent, FS069, a suspension of perfluoropropane-filled albumin microspheres (3.6 microns average microbubble size, concentration 8 x 8(8)/ml), could achieve safe and successful myocardial opacification in open-chest dogs. Seventeen dogs (group 1, n = 7, group 2, n = 10) underwent two-dimensional echocardiography before, during, and after the administration of intravenous FS069. Safety was evaluated by measuring arterial and pulmonary artery pressures, heart rate, blood gases, systolic function, myocardial blood flow, and postmortem analysis of myocardial viability by triphenyl-tetrazolium chloride staining. Efficacy to detect changes in regional myocardial perfusion was assessed by injecting FS069 at baseline, after sequential coronary occlusions and reperfusion, and during intravenous vasodilators with and without coronary occlusions. Results were compared with radiolabeled microspheres. FS069 was found to be safe and effective. In the absence of coronary occlusions, uniform myocardial opacification was observed in all dogs. A perfusion defect was observed in all dogs during coronary occlusions. Background-subtracted peak contrast intensity in the myocardium correctly identified regional myocardial blood flow changes and showed a significant correlation with radiolabeled microspheres (r = 0.65, p = 0.0001).

Albumins↗
PubMed1996

A population-based study of the coverage of cancer patients by hospice services.

The aims were to determine the proportion of terminal cancer patients in South Australia who had involvement with a programme of hospice care, to identify the predictors of hospice involvement, and to consider the influence of hospice services, along with other variables, on the place of death. A file of patients of the State's hospice services who died in 1990 was compiled and linked to the population-based Central Cancer Register. We found that 1561 (56%) of the 2800 cancer patients who died in 1990 had care from a hospice service. Patients were less likely to be involved with a hospice service if they were 80 years or older, lived in a rural region, or had a haematological malignancy, and more likely to have hospice care if they had a survival time of more than six months, or were born in the UK or Europe. Patients of hospice services were more likely than other patients to die at home or in an inpatient hospice, and less likely to die in a nursing home or private hospital. A range of other factors were also found to be associated with place of death. We conclude that there has been a rapid acceptance of hospice care in South Australia, with a majority of the target population of cancer patients covered by services. Epidemiological research methods are useful for identifying gaps in the provision of care, and for determining the impact of various factors on where people die. This research is, therefore, important for the formulation and evaluation of policy for the delivery of terminal care.

Adult↗
PubMed1995

Cost-effectiveness of Helicobacter pylori eradication for the long-term management of duodenal ulcer in Canada.

BACKGROUND: A 1994 National Institutes of Health consensus panel recommended that eradication of Helicobacter pylori should be first-line therapy for persons with duodenal ulcer. OBJECTIVE: To assess the cost-effectiveness of H pylori eradication relative to alternative pharmacologic strategies in the long-term management of persons with confirmed duodenal ulcer. METHODS: Decision analysis model to estimate expected costs and symptomatic ulcer recurrences during a 12-month period for three general treatment strategies: (1) immediate H pylori eradication; (2) H pylori eradication at first ulcer recurrence; and (3) continuous maintenance therapy with a histamine2 receptor antagonist (ranitidine hydrochloride). Two H pylori eradication therapies were compared: classic triple therapy and omeprazole plus amoxicillin. Probabilities for ulcer recurrence are by meta-analysis of published randomized trials. Health care resources used in the management of duodenal ulcer recurrence were by expert physician panel. All costs are in 1993 Canadian dollars. RESULTS: Duodenal ulcer recurrence at 6 months (symptomatic and asymptomatic) with placebo was 65.4% and 12.8% with maintenance ranitidine therapy. Where eradication of H pylori was successful (85% of patients), the ulcer recurrence rate to 12 months was 3.7%. Treatment with ranitidine and triple therapy to eradicate H pylori on first presentation has an expected 1-year cost of $253 with 15 symptomatic recurrences per 100 patients; H pylori eradication by omeprazole plus amoxicillin had similar expected costs ($272) and outcomes (15 recurrences per 100 patients). Both of these early H pylori eradication strategies were dominant (less costly with same or better outcomes) over intermittent or continuous maintenance ranitidine therapy or delayed (after first recurrence) H pylori eradication. CONCLUSION: Our analysis provides economic evidence in support of the recent guidance that for persons with duodenal ulcer, early attempts to eradicate H pylori are recommended.

Canada↗
PubMed1994

Structural requirements for addition of O-linked carbohydrate to recombinant erythropoietin.

To define the structural requirements for addition of O-linked glycosylation in vivo, recombinant erythropoietin (rEPO) variants were constructed. Thirty-three independent Ser or Thr substitutions were constructed and examined to see which were subject to O-linked carbohydrate addition. Variants with Thr mutations at positions 123 and 125, but not elsewhere, contained additional carbohydrate, which suggests that several positions around the existing O-linked glycosylation site (Ser126), but not elsewhere, contain the necessary information for O-linked carbohydrate addition. Two forms of the Thr125 variant were identified. One form was glycosylated only at residue 125, and a second form was glycosylated at both Thr125 and Ser126, the normal O-glycosylation site. We have also found that glycosylation is less efficient when rEPO is improperly folded and that prolines at -1 and +1 relative to the O-glycosylation site enhance glycosylation.

Amino Acid Sequence↗
PubMed1994

Method for simultaneous isolation and quantitation of platelet activating factor and multiple arachidonate metabolites from small samples: analysis of effects of Staphylococcus aureus enterotoxin B in mice.

A novel method has been developed for the extraction and simultaneous separation and quantitation of key arachidonate metabolites and platelet activating factor (PAF) from plasma samples of limited size. Aqueous solutions of these metabolites were added onto a solid phase C-18 cartridge and arachidonate metabolites and PAF were eluted, successively, with acetonitrile-methanol (85:15, v/v), followed by 100% methanol. Arachidonate metabolites (first eluate) were fractionated by C-18 reverse-phase high-performance liquid chromatography using a program designed for the resolution of 31 arachidonate metabolites (3-min separation). The fractions were collected and assayed by radioimmunoassay or radiography, if radioactively labeled. Two internal standards were added to each sample, 15-hydroxyeicosadienoic acid (detected at 235 nm) to determine gradient shifts and [1-14C]eicosatrienoic acid to estimate the recoveries of arachidonate metabolites at any stage of the process. This method was developed to answer specific questions concerning the mode of action of Staphylococcus aureus enterotoxin B (SEB). Plasma samples from mice challenged with SEB were analyzed and major differences were seen in 5-lipoxygenase metabolites. Low doses of SEB vs saline stimulated 5-hydroxyeicosatetraenoic acid production, while high doses of SEB stimulated leukotriene D4 production.

Animals↗
PubMed1994

Receiver operating characteristic evaluation of computer display of adult portable chest radiographs.

RATIONALE AND OBJECTIVES: The suitability of using an image console monitor for interpretation of adult portable chest radiographs was evaluated with receiver operating characteristic (ROC) analysis and subjective techniques. METHODS: Radiologists read 80 chest images, once on a display monitor and once on computed radiography film, for the presence or absence of pneumothorax or atelectasis. Judgments of correct or incorrect positions of tubes and lines were reported, and total viewing time was recorded. RESULTS: A statistically significant difference was found in favor of monitor reading for detection of pneumothoraces. Atelectasis detection also was higher with monitor reading, but the difference did not reach statistical significance. Tube/line judgments were equivalent for both modes. Total viewing time was approximately 1 minute longer per image with the monitor. CONCLUSIONS: Viewing computed radiography images on a workstation monitor does not seem to affect diagnostic accuracy compared with film viewing. Preset image defaults tailored to the individual radiologist could decrease total viewing time to acceptable levels.

Adult↗
PubMed1993

Helicobacter pylori infection in adolescents with eating disorders and dyspeptic symptoms.

The potential role of Helicobacter pylori infection of the antrum as a cause of symptoms of dyspepsia in patients with eating disorders was evaluated with an assay to detect H. pylori-specific IgG in serum. H. pylori-specific optical-density readings were comparable for adolescents with eating disorders (0.133 +/- 0.063, mean +/- SD) and for two comparison groups, and were lower than readings for children with documented H. pylori infection. Symptoms referable to the gastrointestinal tract did not correlate with H. pylori status in the teenagers with eating disorders.

Adolescent↗
PubMed1993

Trends in the terminal care of cancer patients: South Australia, 1981-1990.

BACKGROUND: The increasing numbers of cancer patients, the high costs of terminal care, and the development of palliative care services have led to a growing interest in patterns of terminal cancer care. These patterns are relevant to the formulation and evaluation of health services policy. AIMS: To investigate trends in the place of death of South Australian cancer patients between 1981 and 1990, and to examine associations of socio-demographic and clinical variables with the place of death. METHODS: Data relating to 2715 deaths attributed to cancer in 1990 were extracted from the Central Cancer Registry. To assess trends, these data were directly standardised to the age-sex distribution of cancer deaths in 1981 and 1985 which were investigated in a previous study. Unconditional logistic regression was used to investigate predictors of place of death. RESULTS: The proportion of deaths which occurred in major metropolitan public hospitals decreased from 40% in 1981 to 28% in 1990. Conversely, the proportion which occurred in hospice units increased from 5% to 20% over the same period. There was a decline in the proportion of deaths which occurred in private hospitals, but there was no significant change in the proportion which occurred in country hospitals or nursing homes. The proportion of deaths at home remained around 14%. Associated with place of death were age, sex, type of malignancy, survival time from diagnosis to death, Aboriginality, and area of residence. Further research to assess the clinical appropriateness of terminal care patterns is suggested.

Aged↗
PubMed1993

Armadillos (Dasypus novemcinctus) as a model to test antileprosy vaccines; a preliminary report.

The efficacy of two candidate leprosy vaccines, BCG and a mixture of BCG and killed Mycobacterium leprae, was tested in 62 armadillos caught in the wild. The abilities of the vaccines to convert lepromin-negative armadillos to a positive reaction were compared with a group of control animals. Both vaccines upgraded subsequent lepromin skin-test histopathology. The conversion results parallel the protection values obtained in some BCG vaccine trials against leprosy in humans. Before conducting expensive human trials with new antileprosy vaccines, it would be worthwhile first to evaluate them in the armadillo model.

Animals↗
PubMed1993

Therapeutic role of dietary fibre.

The current status of dietary fibre and fibre supplements in health and disease is reported, and the components of dietary fibre and its respective mechanical and metabolic effects with emphasis on its therapeutic potential are reviewed. Practical management guidelines are provided to help physicians encourage patients identified as having fibre deficiency to increase dietary fibre intake to the recommended level.

Adult↗