PubMed Health⌕ Search

Biomedical subjects

R Burns

Publications and source records attributed to R Burns.

At least 19 recordsLinked to original sources
PubMed2006

Reducing transfer times for coronary angiography in patients with acute coronary syndromes: one solution to a national problem.

BACKGROUND: Patients with acute coronary syndrome (ACS) are at high risk of further cardiac events and benefit from early intervention, as reflected by international guidelines recommending early transfer to interventional centres. The current average waiting time of up to 21 days contravenes evidence based early intervention, creates geographical inequity of access, wastes bed days, and is unsatisfactory for patients. METHODS: A regional transfer unit (RTU) was created to expatriate access of ACS patients referred from other centres to the revascularisation service. By redesigning the care pathway patients arriving on the RTU undergo angiography within 24 hours, and then leave the RTU the following day, allowing other ACS patients to be treated. RESULTS: During the first six months of the RTU, the mean waiting time from referral to procedure decreased from 20 (SD 15) days (range 0-51) to 8 (SD 3) days (range 0-21) for 365 patients transferred from a district general hospital. Ninety seven per cent of patients underwent angiography within 24 hours, 61% having undergone percutaneous coronary intervention at the same sitting, and 78% were discharged home within 24 hours. CONCLUSIONS: Delivering standards laid out in the National Service Framework, reducing inequalities of care across the region, and facilitating evidence based strategies of care represents a challenging and complex issue. For high risk patients suffering ACS who need early invasive investigation, a coordinated network wide approach together with the creation of an RTU resulted in a 62% reduction in waiting times for no extra resources. Further improvements can be expected through increased capacity of this verified strategy.

Angioplasty, Balloon, Coronary↗
PubMed2005

Anterior hypothalamic vasopressin modulates the aggression-stimulating effects of adolescent cocaine exposure in Syrian hamsters.

Repeated low-dose cocaine treatment (0.5 mg/kg/day) during adolescence induces offensive aggression in male Syrian hamsters (Mesocricetus auratus). This study examines the hypothesis that adolescent cocaine exposure predisposes hamsters to heightened levels of aggressive behavior by increasing the activity of the anterior hypothalamic-vasopressinergic neural system. In a first experiment, adolescent male hamsters were treated with low-dose cocaine and then scored for offensive aggression in the absence or presence of vasopressin receptor antagonists applied directly to the anterior hypothalamus. Adolescent cocaine-treated hamsters displayed highly escalated offensive aggression that could be reversed by blocking the activity of vasopressin receptors within the anterior hypothalamus. In a second set of experiments, adolescent hamsters were administered low-dose cocaine or vehicle, tested for offensive aggression, and then examined for differences in vasopressin innervation patterns and expression levels in the anterior hypothalamus, as well as the basal- and stimulated-release of vasopressin in this same brain region. Aggressive, adolescent cocaine-treated hamsters showed no differences in vasopressin afferent innervation and/or peptide levels in the anterior hypothalamus compared with non-aggressive, saline-treated littermates. Conversely, significant increases in stimulated, but not basal, vasopressin release were detected from the anterior hypothalamus of aggressive, cocaine-treated animals compared with non-aggressive, saline-treated controls. Together, these data suggest that adolescent cocaine exposure increases aggression by increasing stimulated release of vasopressin in the anterior hypothalamus, providing direct evidence for a causal role of anterior hypothalamic-vasopressin activity in adolescent cocaine-induced offensive aggression. A model for how alterations in anterior hypothalamic-vasopressin neural functioning may facilitate the development of the aggressive phenotype in adolescent-cocaine exposed animals is presented.

Age Factors↗
PubMed2004

Epidural anaesthesia for caesarean section in a patient with quadriplegia and autonomic hyperreflexia.

The anaesthetic management of a pregnant quadriplegic woman with a history of autonomic hyperreflexia is discussed. Autonomic hyperreflexia is a life-threatening complication of high spinal cord transection, for which labour is a well known stimulus. It can lead to uncontrolled hypertension. We discuss the anaesthetic considerations in planning the care of this patient, who was managed for elective caesarean section and post partum hypertension with epidural anaesthesia.

Adult↗
PubMed2003

A comparison of target-controlled therapy with patient-controlled administration of propofol combined with midazolam for sedation during dental surgery.

Forty anxious day case patients undergoing extraction of third molar teeth under local anaesthesia with sedation, were studied in a randomised double-blind controlled trial. A target-controlled infusion of propofol was compared with patient-controlled propofol for sedation, combined with a small dose of midazolam to improve amnesia. The objectives of the study were to measure the total dose of propofol used by the two groups and assess recovery and patient satisfaction. The mean dose of propofol used in the patient-controlled sedation group was significantly less than the target-controlled group (p < 0.00007). Five patients became over-sedated in the target-controlled group compared with none in the patient-controlled group. Only one of the three tests of performance showed that the target-controlled patients were more sedated. Patient satisfaction was high in both groups despite a greater recollection of events in the patient-controlled group.

Adult↗
PubMed2000

Bone-related mineral content of water samples collected on the Navajo reservation.

Although dairy food intake is low among the Navajo people, hip fracture rates are lower than in Caucasians. Genetic differences in bone density have been cited as the reasons for low fracture rates among Native Americans and other segments of the population. However, more detailed examination of mineral intakes suggests that environmental factors may provide part of the explanation for the lower fracture rates. Cultural practices such as the addition of ash to traditional foods and the high mineral content of water may provide much higher intakes of bone-related minerals than food intake surveys have previously reported. As part of a larger study to assess overall intake of minerals related to bone health and other conditions, water samples were collected from the Navajo reservation. Duplicates were collected at least one week apart from 53 sites including wells, springs, taps, and storage barrels and analyzed by atomic absorption and inductively coupled plasma spectrometry for a number of minerals. For average intakes of 2 l/day, water could provide up to 212 mg of calcium, 150 mg of magnesium and 8 mg of zinc. The combined contribution of mineral intakes provided by the addition of juniper ash to traditional foods, not genetic differences, may partially explain the lower fracture rates of the Navajo people. Further research in this area is required to confirm this hypothesis.

Bone and Bones↗
PubMed2000

Interdisciplinary geriatric primary care evaluation and management: two-year outcomes.

BACKGROUND: The long-term efficacy of interdisciplinary outpatient primary care Geriatric Evaluation and Management (GEM) has not been proven. This article focuses on results obtained during the 2 years of the study. METHODS: In this 2-year randomized clinical trial, at the Veterans Affairs Medical Center, Memphis, TN, 128 veterans, age 65 years and older, were randomized to outpatient GEM or usual care (UC). Two-year follow-up analyses are based on the 98 surviving individuals. Study outcome measurements included health status, function, and quality of life including affect, cognition, and mortality. RESULTS: At 2 years, there were positive intervention effects for eight of 1 outcome measures, five of which had attained significance at 1 year. GEM subjects, compared with UC subjects, had significantly greater improvement in health perception (P = .001), smaller increases in numbers of clinic visits (P = .019) and instrumental activities of daily living (IADL) impairments (P = .006), improved social activity (P<.001), greater improvement in Center for Epidemiologic Studies-Depression (CES-D) scores (P = .003), general well-being (P = .001), life satisfaction (P<.001), and Mini-Mental State Exam (MMSE) scores (P = .025). There were no significant treatment effects in activities of daily living (ADL) scores (P = .386), number of hospitalizations (P = .377), or mortality (P = .155). CONCLUSIONS: These findings suggest that a primary care approach that combines an initial interdisciplinary comprehensive assessment with long-term, interdisciplinary outpatient management may improve outcomes for targeted older adults significantly. Findings suggest further that outcomes may continue to improve over time and that the GEM care model provides an effective way to manage health care of older adults.

Activities of Daily Living↗
PubMed2000

Long-term exercise and its effect on balance in older, osteoarthritic adults: results from the Fitness, Arthritis, and Seniors Trial (FAST).

OBJECTIVES: To examine the effects of 18-month aerobic walking and strength training programs on static postural stability among older adults with knee osteoarthritis. DESIGN: Randomized, single-blind, clinical trial of therapeutic exercise. SETTING: Both center-based (university) and home-based. PARTICIPANTS: A cohort of 103 older adults (age = 60 years) with knee osteoarthritis who were participants in a large (n = 439) clinical trial and who were randomly assigned to undergo biomechanical testing. INTERVENTION: An 18-month center- (3 months) and home-based (15 months) therapeutic exercise program. The subjects were randomized to one of three treatment arms: (1) aerobic walking; (2) health education control; or (3) weight training. MEASUREMENTS: Force platform static balance measures of average length (Rm) of the center of pressure (COP), average velocity (Vel) of the COP, elliptical area (Ae) of the COP, and balance time (T). Measures were made under four conditions: eyes open, double- and single-leg stances and eyes closed, double- and single-leg stances. RESULTS: In the eyes closed, double-leg stance condition, both the aerobic and weight training groups demonstrated significantly better sway measures relative to the health education group. The aerobic group also demonstrated better balance in the eyes open, single-leg stance condition. CONCLUSIONS: Our results suggest that long-term weight training and aerobic walking programs significantly improve postural sway in older, osteoarthritic adults, thereby decreasing the likelihood of larger postural sway disturbances relative to a control group.

Aged↗
PubMed2000

Human coronavirus 229E infects polarized airway epithelia from the apical surface.

Gene transfer to differentiated airway epithelia with existing viral vectors is very inefficient when they are applied to the apical surface. This largely reflects the polarized distribution of receptors on the basolateral surface. To identify new receptor-ligand interactions that might be used to redirect vectors to the apical surface, we investigated the process of infection of airway epithelial cells by human coronavirus 229E (HCoV-229E), a common cause of respiratory tract infections. Using immunohistochemistry, we found the receptor for HCoV-229E (CD13 or aminopeptidase N) localized mainly to the apical surface of airway epithelia. When HCoV-229E was applied to the apical or basolateral surface of well-differentiated primary cultures of human airway epithelia, infection primarily occurred from the apical side. Similar results were noted when the virus was applied to cultured human tracheal explants. Newly synthesized virions were released mainly to the apical side. Thus, HCoV-229E preferentially infects human airway epithelia from the apical surface. The spike glycoprotein that mediates HCoV-229E binding and fusion to CD13 is a candidate for pseudotyping retroviral envelopes or modifying other viral vectors.

Cell Line↗
PubMed2000

The impact of time to thrombolytic treatment on outcome in patients with acute myocardial infarction. For the CORE investigators (Collaborative Organisation for RheothRx Evaluation).

OBJECTIVES: To examine the impact of time to thrombolytic treatment on multiple acute outcome variables in a single trial of thrombolysis in acute myocardial infarction. DESIGN AND PATIENTS: Mortality and reinfarction rate were measured in 2770 patients with acute myocardial infarction who received thrombolysis within 12 hours in CORE, an international, dose ranging trial of poloxamer 188. Tc-99m sestamibi infarct size and radionuclide angiographic ejection fraction substudies included 1099 and 1074 patients, respectively. RESULTS: Time to thrombolysis, subgrouped by intervals (< 2, 2-4, > or = 4-6, and > or = 6 hours), was significantly associated with infarct size (median 15.0%, 18.5%, 22.0%, 18.5% of left ventricle; p = 0.033), mean (SD) ejection fraction (51.5 (12.0)%, 48. 3 (13.9)%, 48.2 (13.3)%, 48.2 (15.0)%; p = 0.006), 35 day mortality (5.7%, 7.1%, 7.9%, 12.5%; p = 0.0004), six month mortality (7.3%, 8. 6%, 10.4%, 15.5%; p < 0.0001), and 35 day reinfarction rate (6.1%, 3. 2%, 4.0%, 0.9%; p = 0.0001). CONCLUSIONS: In this single large trial, the beneficial effect of time to thrombolysis on infarct size and ejection fraction was restricted to treatment given within two hours of symptom onset, while the effect on mortality was evident over all time intervals. Reinfarction rate was higher in patients treated with earlier thrombolysis.

Humans↗
PubMed2000

Perceptions of danger, risk taking, and outcomes in a remote community.

On the surface, the severity of the Antarctic environment is sufficient to account for the injury rates that might occur there. However, it is argued that injury occurrence is the outcome of multiple factors. A number of such factors, both in the nature of work in the Antarctic and in the characteristics of the human beings who work there are reviewed. An area that has received little attention is individual risk perceptions. It is contended that risk perceptions need to be taken into account when assessing the contributing factors to individual risk taking, as measured by accidents that occur. The literature on risk perceptions is reviewed as a precursor to an empirical study of risk perceptions and injuries at an Antarctic station. The referent for expeditioner practice and home comparisons is Australia.

Accidents↗
PubMed2000

Clathrin plays a novel role in the regulation of cell polarity, pseudopod formation, uropod stability and motility in Dictyostelium.

Although the traditional role of clathrin has been in vesicle trafficking and the internalization of receptors, a novel role in cytokinesis was recently revealed in an analysis of a clathrin-minus Dictyostelium mutant (chc(-)). chc(-) cells grown in suspension were demonstrated to be defective in assembling myosin II into a normal contractile ring. To test whether this defect reflected a more general one of cytoskeletal dysfunction, chc(-) cells were analyzed for cell polarity, pseudopod formation, uropod stability, cell locomotion, chemotaxis, cytoskeletal organization and vesicle movement. chc(-) cells crawled, chemotaxed, localized F-actin in pseudopods, organized their microtubule cytoskeleton in a relatively normal fashion and exhibited normal vesicle dynamics. Although chc(-) cells extended pseudopods from the anterior half of the cell with the same frequency as normal chc(+) cells, they extended pseudopods at twice the normal frequency from the posterior half of the cell. The uropods of chc(-) cells also exhibited spatial instability. These defects resulted in an increase in roundness, a reduction in polarity, a reduction in velocity, a dramatic increase in turning, a high frequency of 180 degrees direction reversals and a decrease in the efficiency of chemotaxis. All defects were reversed in a rescued strain. These results are the first to suggest a novel role for clathrin in cell polarity, pseudopod formation, uropod stability and locomotion. It is hypothesized that clathrin functions to suppress pseudopod formation and to stabilize the uropod in the posterior half of a crawling cell, two behavioral characteristics that are essential for the maintenance of cellular polarity, efficient locomotion and efficient chemotaxis.

Actins↗
PubMed2000

The optimal outcomes of post-hospital care under medicare.

OBJECTIVE: To estimate the differences in functional outcomes attributable to discharge to one of four different venues for post-hospital care for each of five different types of illness associated with post-hospital care: stroke, chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF), hip procedures, and hip fracture, and to estimate the costs and benefits associated with discharge to the type of care that was estimated to produce the greatest improvement. STUDY SETTING/DATA SOURCES: Consecutive patients with any of the target diagnoses were enrolled from 52 hospitals in three cities. Data sources included interviews with patients or their proxies, medical record reviews, and the Medicare Automated Data Retrieval System. ANALYSIS: A two-stage regression model looked first at the factors associated with discharge to each type of post-hospital care and then at the outcomes associated with each location. An instrumental variables technique was used to adjust for selection bias. A predictive model was created for each patient to estimate how that person would have fared had she or he been discharged to each type of care. The optimal discharge location was determined as that which produced the greatest improvement in function after adjusting for patients' baseline characteristics. The costs of discharge to the optimal type of care was based on the differences in mean costs for each location. DATA COLLECTION/EXTRACTION METHODS: Data were collected from patients or their proxies at discharge from hospital and at three post-discharge follow-up times: six weeks, six months, and one year. In addition, the medical records for each participant were abstracted by trained abstractors, using a modification of the Medisgroups method, and Medicare data were summarized for the years before and after the hospitalization. PRINCIPAL FINDINGS: In general, patients discharged to nursing homes fared worst and those sent home with home health care or to rehabilitation did best. Because the cost of rehabilitation is high, greater use of home care could result in improved outcomes at modest or no additional cost. CONCLUSIONS: Better decisions about where to discharge patients could improve the course of many patients. It is possible to save money by making wiser discharge planning decisions. Nursing homes are generally associated with poorer outcomes and higher costs than the other post-hospital care modalities.

Activities of Daily Living↗
PubMed1999

Structural responses to the photolytic release of ATP in frog muscle fibres, observed by time-resolved X-ray diffraction.

1. Structural changes following the photolytic release of ATP were observed in single, permeabilised fibres of frog skeletal muscle at 5-6 C, using time-resolved, low-angle X-ray diffraction. The structural order in the fibres and their isometric function were preserved by cross-linking 10-20 % of the myosin cross-bridges to the thin filaments. 2. The time courses of the change in force, stiffness and in intensity of the main equatorial reflections (1,0) and (1,1), of the third myosin layer line (M3) at a reciprocal spacing of (14.5 nm)-1 on the meridian and of the first myosin-actin layer line (LL1) were measured with 1 ms time resolution. 3. In the absence of Ca2+, photolytic release of ATP in muscle fibres initially in the rigor state caused the force and stiffness to decrease monotonically towards their values in relaxed muscle fibres. 4. In the presence of Ca2+, photolytic release of ATP resulted in an initial rapid decrease in force, followed by a slower increase to the isometric plateau. Muscle fibre stiffness decreased rapidly to approximately 65 % of its value in rigor. 5. In the absence of Ca2+, changes on the equator, in LL1 and in M3 occurred with a time scale comparable to that of the changes in tension and stiffness. 6. In the presence of Ca2+, the changes on the equator and LL1 occurred simultaneously with the early phase of tension decrease. The changes in the intensity of M3 (IM3) occurred on the time scale of the subsequent increase in force. The time courses of the changes in tension and IM3 were similar following the photolytic release of 0. 33 or 1.1 mM ATP. However the gradual return towards the rigor state began earlier when only 0.33 mM ATP was released. 7. In the presence of Ca2+, the time course of changes in IM3 closely mimicked that of force development following photolytic release of ATP. This is consistent with models that propose that force development results from a change in the average orientation of cross-bridges, although other factors, such as their redistribution, may also be involved.

Adenosine Triphosphate↗
PubMed1999

Survival of patients with high grade glioma treated with intrathecal thiotriethylenephosphoramide for ependymal or leptomeningeal gliomatosis.

BACKGROUND: The diagnosis of leptomeningeal dissemination of malignant glioma (meningeal gliomatosis) is associated with poor survival. Intrathecal (IT) chemotherapeutic agents used to achieve tumor control and improve survival include methotrexate, cytosine arabinoside (ara-C), thiotriethylenephosphoramide (thio-TEPA), neocarzinostatin, and 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)-1-nitros ourea hydrochloride (ACNU). Little information exists about survival following administration of IT chemotherapy. The authors report survival data from a series of patients with supratentorial anaplastic astrocytoma (AA) or glioblastoma multiforme (GBM) treated for ependymal or leptomeningeal gliomatosis with IT thio-TEPA. METHODS: The authors reviewed the records of 14 patients treated between 1991 and 1997 (GBM: n = 9; AA: n = 5). All patients were diagnosed with ependymal (n = 8) or leptomeningeal (n = 6) dissemination of tumor on the basis of clinical signs and symptoms, ependymal or leptomeningeal contrast enhancement on magnetic resonance imaging (MRI), and/or cerebrospinal fluid analysis. All 14 patients underwent placement of a ventricular reservoir system and subsequent instillation of IT thio-TEPA on a weekly basis for 6-12 weeks. Response to treatment was evaluated clinically and by MRI at intervals of 1-3 months and 3-6 months from the initiation of IT thio-TEPA. Data on survival from the time of diagnosis of dissemination was assessed. RESULTS: The median survival, from the time of diagnosis of ependymal or leptomeningeal dissemination, of patients who received IT thio-TEPA was 10 months (AA = 19 months; GBM = 10 months). Five of 14 patients had a radiographic response to treatment within 6 months. The median survival of patients with a radiographic response was 15.5 months, compared with 10 months for nonresponders. No significant neurotoxicity or myelopathy was observed. CONCLUSIONS: Early treatment with IT thio-TEPA may result in improved survival with minimal morbidity. Radiographic response may predict prolonged survival.

Adult↗