Search PubMed⌕ Search

Biomedical subjects

K Burke

Publications and source records attributed to K Burke.

At least 37 records · Page 2Linked to original sources
PubMed1998

External beam radiation therapy for choroidal neovascularization.

OBJECTIVE: This study aimed to determine the effect of external beam radiation therapy on choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD). DESIGN: The study design was a nonrandomized clinical trial with an historic control group. PARTICIPANTS: A total of 91 patients were treated with external beam radiation. These patients were compared retrospectively to the 119 patients in a control group. INTERVENTION: Patients with subfoveal CNV who did not meet the criteria for laser treatment defined by published reports from the Macular Photocoagulation Study Group or who did not want laser treatment were considered for radiation therapy in a nonrandomized, prospective clinical trial. Additional entry criteria for this prospective study included visual acuity better than or equal to 20/320 on the Early Treatment Diabetic Retinopathy Study chart and a lesion size less than 12 disc areas. The patients were treated with 5 fractions of 200 cGy 6 MV external beam photons. MAIN OUTCOME MEASURES: The visual acuity measured at baseline was compared to the visual acuity after 1 year of follow-up. RESULTS: The mean baseline visual acuity of the 91 patients entered into the Radiation Study was 20/80. After 1 year, 83 patients (91.2%) completed follow-up, and their mean visual acuity dropped to 20/200. By comparison, the mean baseline visual acuity of the control patients also was 20/80, and after 1 year, the control subjects had a mean visual acuity of 20/125. At 1 year of follow-up, 49.4% of patients treated with radiation and 38.1% of the control subjects lost 3 or more lines of visual acuity (P = 0.16). CONCLUSIONS: This study found that external beam radiation using 1000 cGy in 5 fractions, a dose similar to that used in previous studies, was not effective in the treatment of CNV secondary to AMD. These results suggest that patients should not be treated with this dose of external beam radiation for CNV secondary to AMD.

Aged↗
PubMed1998

Can gerontological nursing survive?

By the year 2041, 11 million individuals 65 and over will reside in Canada. This drastic demographic change, coupled with the increasing acuity and complexity of the health care needs of seniors, creates an immense demand for nurses specialized in gerontology. But can gerontological nursing survive as a specialty and respond to this demand?

Aged↗
PubMed1997

The gift relationship between pharmaceutical companies and physicians: an exploratory survey of physicians.

The purpose of this exploratory study was to survey physicians' attitudes surrounding the 'gift relationship' between pharmaceutical companies and physicians. A survey was mailed to 1000 randomly selected West Virginia physicians, of which 283 (28.3%) responses were received. The most commonly received gifts reported by the study physicians were trinkets (77.4%), followed by books (41.7%) and meals (41%). Principal component analysis and varimax rotation identified seven physician belief constructs. The mean ratings of the constructs indicated that the physicians slightly agreed that pharmaceutical companies give gifts to physicians to influence their prescribing, moderately disagreed that they do so as a form of professional recognition of physicians, and strongly disagreed that their prescribing behaviour could be influenced by the gifts they receive. Physicians slightly disagreed that pharmaceutical companies' sponsoring of CME programmes are only promotional gimmicks. Although the study physicians slightly disagreed that it may be inappropriate for them to accept gifts from pharmaceutical companies, they seemed slightly averse to having 'gift relationships' between pharmaceutical companies and physicians made public. Correlation analysis suggested that physicians who have a large number of patients in their practice, see a larger number of patients per day, or write a large number of prescriptions per day are more likely to be offered gifts by pharmaceutical companies, and they are also more likely to condone the practice of gift giving and receiving.

Attitude of Health Personnel↗
PubMed1997

Optimization and deconvolution of lithium fluoride TLD-100 in diagnostic radiology.

Lithium fluoride (LiF) TLD-100 is one of the most commonly used thermoluminescent (TL) materials for the measurement of entrance surface dose (ESD) in diagnostic radiology. However, the minimum detectable dose (MDD) achieved, as derived from measurements of the random uncertainty present in the background signal, is usually quoted as being 50-100 microGy. A more appropriate definition of MDD for use in the clinical setting is the dose at which measurements exhibit a specified level of random uncertainty. This definition will give rise to a higher value for the MDD. An MDD of 50-100 microGy precludes accurate measurement of ESD in high tube potential (kVp) chest or neonatal radiography. Techniques described in the specialist literature for the reduction of the MDD of LiF were assessed both in the laboratory, and during a patient dose survey of high kVp chest radiography. Optimization of the pre-irradiation annealing and post-irradiation TL read heating cycles in terms of sensitivity and precision resulted in an MDD of 5/80 microGy (derived from background signal variation and 20% random uncertainty at 95% confidence limits, respectively). Deconvolution of the glowcurve was found to result in an MDD of approximately 10 microGy. Clinical measurements were contrasted with calculated values derived from ionization chamber measurements of tube output. The results support the hypothesis that glowcurve deconvolution permits the measurement of ESDs from low dose examinations using basic TL dosimetry equipment available to virtually all medical physics departments.

Fluorides↗
PubMed1997

Encouragement during maximal exercise testing of type A and type B scorers.

The influence of verbal encouragement during assessment of maximal oxygen consumption of subjects scoring as Type A and Type B on the Jenkins Activity Survey, Form T was examined. Fourteen Type A and 12 Type B scorers performed two randomly assigned tests on a motor-driven treadmill with and without verbal encouragement during testing. Treadmill time, oxygen consumption (VO2), heart rate, and respiratory exchange ratio at exhaustion were examined. Verbal encouragement led to significantly greater treadmill time, VO2, and respiratory exchange ratio for Type B scorers when compared with the non-encouragement trial. Treadmill time, VO2, heart rate, and respiratory exchange ratio at exhaustion were not different between treatments for the Type A scorers. Type A scorers ran significantly longer without encouragement than Type B scorers; however, when encouragement was provided, treadmill time for Type A and Type B scorers did not differ significantly. The results suggest that attainment of maximal effort is not dependent on verbal encouragement for Type A scorers, whereas verbal encouragement is necessary to assure attainment of maximal physiologic effort for those individuals scoring as Type B.

Adult↗
PubMed1996

The changing face of carotid endarterectomy.

PURPOSE: The economic milieu and improvements in care have altered the diagnostic and therapeutic algorithm of the patient with carotid stenosis. This study analyzes the efficacy and safety of these changes. METHODS: The records of patients who underwent 320 consecutive carotid endarterectomies performed by three surgeons at our institution from 1990 to 1994 were reviewed retrospectively. Use of diagnostic angiography, use of carotid duplex ultrasound, length of hospital stay, postanesthesia recovery observation, intensive care unit (ICU) observation, complications, and hospital charges were analyzed. RESULTS: The average length of hospital stay decreased from 6.18 days to 2.00 days (p < or = 0.001). The day of discharge decreased from 3.10 days to 1.24 days after surgery (p < or = 0.01). By 1993, 68% were discharged by the first day after surgery, increasing to 73% by 1994. From 1990 to 1992, average postoperative ICU observation time fluctuated between 18 and 25 hours; this time decreased to 12.2 hours by 1994. In 1993, only 12.5% of patients were admitted to the ICU, down from 94.8% in 1990; by 1994, only 7.3% were admitted to the ICU (p < or = 0.001). Postanesthesia recovery observation time decreased from 3.77 hours to 1.63 hours during this time (p < or = 0.04). With regard to preoperative diagnosis, angiography was performed in 93.1% of patients in 1990; by 1994, only 32.8% underwent this procedure (p < or = 0.0001). Average hospital charges decreased significantly (1990, $14,378; 1994, $10,436) with these modifications in patient care (p < or = 0.001). The complication rate reflected no significant changes over the course of the study. There were six incidences of cerebrovascular accident (6/320, 1.9%), including one death. There were four incidences of transient ischemic attack (4/320, 1.3%), with no significant differences noted from year to year. CONCLUSIONS: This study confirms the changing nature of carotid endarterectomy and documents that these changes have not adversely affected the safety of the operation.

Adult↗
PubMed1996

The tympanic membrane thermometer in paediatrics: a review of the literature.

This literature review looks at published works on the accuracy, reliability and sensitivity of the tympanic membrane thermometer in the paediatric population, particularly in relation to those who present in the Accident and Emergency department. Decisions that influence patient care outcomes are often based on information obtained from taking the child's temperature. Numerous studies have been conducted to examine temperature sites and instruments used. The most recent temperature measuring device to be used by nurses in assessing their patients is the tympanic membrane thermometer. The advantages of tympanic membrane temperature measurement include ease of use, rapid results and convenience for both nurse and child. However, inconsistent study reports have revealed some concerns about the use of the tympanic membrane thermometer as a routine measurement tool of body temperature in children. To meet the goal of accurate assessment of body temperature the practitioner must understand the principles behind the use of the tympanic membrane thermometer and thus use it appropriately.

Child↗
PubMed1996

Intensive care after carotid endarterectomy: a prospective evaluation.

BACKGROUND: Through prior investigation we established that only a small minority of patients who undergo carotid endarterectomy (CEA) have a complicated postoperative course requiring an intensive care unit (ICU) stay. An appropriate policy for patient management was established. This study prospectively analyzes the safety and efficacy of this policy. STUDY DESIGN: Patients were transferred directly to a nonmonitored surgical ward, regardless of preoperative comorbidity, if they remained stable from a neurologic and a hemodynamic standpoint during a short (less than three hour) stay in the recovery room. Patients whose status was questionable remained in recovery longer or were transferred to an ICU. RESULTS: One hundred forty-six (79 percent) of 185 patients were transferred safely to a ward. Average length of stay in recovery was one hour 59 minutes. No complications occurred that required a return to the operating suite or a move to an ICU. Most of these patients (88 percent) were discharged within 24 hours of surgery. Thirty-nine (21 percent) patients, each identified in recovery, required intervention or monitoring in an intensive care setting. Fourteen required prolonged, aggressive intravenous treatment of hypertension; 14 had sustained hypotension; three were observed to rule out myocardial infarction, and three had neurologic deficits. Two patients had ventricular arrhythmias, two had wound hematomas, and one patient required reintubation. This group (n = 39) remained in the recovery room two hours 40 minutes on average, spent 20 hours in the ICU, and remained in the hospital 32 hours after CEA. CONCLUSIONS: Most patients who undergo CEA follow a predictably benign postoperative course. Patients are easily identified by a recovery room protocol and approximately 80 percent can avoid ICU costs.

Aged↗
PubMed1995

Corticosteroid alteration of carboplatin-induced hematopoietic toxicity in a murine model.

Corticosteroids exhibit extensive hematopoietic effects both in vitro and in vivo. Some of the previously studied effects suggested that corticosteroids may alter hematopoietic toxicity of chemotherapeutic agents. In this study, we examined (1) the optimum dose and schedule of cortisone acetate (CA) to reduce hematopoietic toxicity of carboplatin (CB) and (2) possible mechanisms involved in this protective effect. CA given subcutaneously at 0.5 mg/d per mouse for 7 days before CB reduced CB-induced mortality due to neutropenia from 88% in controls to 14% in CA-treated mice (P < .05). Lower CA doses were not effective. Three days of pretreatment (but not 1 day) was as effective as 7 days. CA given after CB had no effect on mortality. Pharmacokinetic studies of CA at 0.5 mg per mouse demonstrated blood levels of cortisol achievable in patients (peak level, 82 micrograms/dL). CA treatment markedly reduced spleen cell number and colony-forming units-granulocyte/macrophage (CFU-GM) as well as bone marrow CFU-GM. Bone marrow CFU-GM removed from CA-treated mice demonstrated increased resistance to platinum and increased resistance to high specific activity 3H-thymidine. These findings suggest that treatment of mice with CA induces cellular resistance of hematopoietic precursors to platinum and, thus, reduces CB hematotoxicity. CA or other corticosteroids may be useful in reducing clinical toxicity of CB.

Animals↗
PubMed1995

Peptides control the gain and loss of allele specificity by mutated MHC class I molecules.

To analyze the molecular basis of MHC class I allele-restricted peptide recognition, a set of eight Ld/Lq mutants was constructed and tested for peptide recognition by allele-restricted and peptide-specific CTL. The MHC molecules H-2Ld and H-2Lq differ at six amino acid positions (95, 97, 107, 116, 155, 157) located within the alpha 2 domain of the molecule. Both molecules present the lymphocytic choriomeningitis virus (LCMV) nucleoprotein-derived peptide RPQASGVYM and the murine cytomegalovirus (MCMV) pp89-derived peptide YPHFMPTNL to the respective virus-specific CD8+ CTL is a strictly allele-restricted fashion. All mutated MHC class I molecules did still bind the LCMV peptide and seven of eight mutants retained MCMV peptide binding. The exchange Arg-->Trp at position 97 of Lq in pocket C of the peptide binding groove prevented binding of the MCMV ligand and this loss was compensated by the additional exchange of Ile-->Leu in position 95 (pocket F). Within the Lq molecule, single mutations at either position 97 on the floor of the groove or position 155 of the wall sufficed for a gain of LCMV peptide recognition by Ld-restricted CTL. Altogether, six of eight mutants resulted in a gain of recognition by CTL specific for the other allele. Thus, six of the eight mutants lost MHC-restricted recognition and were accepted by both Ld- as well as Lq-restricted CTL when presenting the LCMV peptide. Only one case of simultaneous recognition of the MCMV peptide by both Ld- as well as Lq-restricted CTL was noted. In other mutations, a gain of recognition by Ld-restricted CTL was associated with a loss of recognition of Lq-restricted CTL. Analysis of extracted MCMV peptide from mutant molecules excluded quantitative differences in presented MCMV peptide as a reason for the lack of CTL recognition. Altogether, the results show that, rather than aminoacids at certain residue positions, individual peptides govern MHC allele specificity of CTL recognition.

Alleles↗
PubMed1995

Selective use of the intensive care unit following carotid endarterectomy.

The purpose of this study was to develop criteria by which selected patients can be observed solely on the ward following carotid endarterectomy (CEA). One hundred consecutive CEA patients were retrospectively reviewed. Preoperative medical conditions were identified, and the postanesthesia recovery room course was reviewed in an attempt to predict the need for intensive care unit (ICU) level care. Forty-four of our 100 patients developed perioperative complications or conditions that required some intervention. Conditions included hypertension in 23, hypotension in nine, arrhythmias in six, and myocardial ischemia in two. Complications included nonfatal cerebrovascular accident (CVA) in one, fatal CVA in one, and postoperative bleeding in two. Sixteen patients required ICU level intervention (hypertension in five, hypotension in five, arrhythmias in two, nonfatal CVA in one, fatal CVA in one, and postoperative bleeding in two. Fifteen of the 16 were identified in the recovery room. Fifty-three patients had a medical history of significant hypertension (42), cardiac disease (27), and/or recent CVA (seven). Thirty-six (68%) of these patients required perioperative intervention in some form; 12 (23%) required ICU level therapy. Eight of 47 (17%) patients without a significant medical history required intervention; only four (9%) required ICU level care. All eight patients were identified in recovery. Only 16 of 100 CEA patients required ICU level care. Fifteen of 16 were identified in recovery. Certain patients identified in the recovery room can be followed safely in a less intense and costly setting.

Adult↗