Biomedical subjects

James Burke

Publications and source records attributed to James Burke.

7 recordsLinked to original sources

PubMed2006

Coronary arterial revascularization: past, present, future: part I--historical trials.

Advances in coronary artery revascularization have been accompanied by clinical trials evaluating these advances. From the Coronary Artery Surgery Study and Bypass Angioplasty Revascularization Investigation to the more recent Arterial Revascularization Therapy Study (ARTS1) and the Medicine, Angioplasty, or Surgery Study (MASS2), these clinical trials provide us with a rationale for the way we conduct clinical practice. This paper reviews the data supporting historical revascularization strategies for our patients, including medical therapy, angioplasty, and bare metal stents. Several recurrent themes emerge. These include a need for increased revascularization in patients who undergo percutaneous treatments, the durability of surgical arterial revascularization, and the importance of medical therapy as the mainstay of treatment. Part II will address newer therapies.

Angioplasty, Balloon, Coronary↗

PubMed2006

Coronary artery revascularization: past, present, future: part II--newer technologies.

Advances in coronary artery revascularization have been accompanied by clinical trials evaluating these advances. Part I of this paper addressed historic trials related to coronary artery revascularization. This paper reviews the data supporting newer revascularization strategies for our patients, including drug-eluting stents and off-pump coronary artery bypass surgery. Benefits include reduced repeat revascularization in patients who undergo percutaneous treatments with drug-eluting stents, the durability of surgical arterial revascularization, and the importance of medical therapy as the mainstay of treatment.

Clinical Trials as Topic↗

PubMed2006

Ocular changes after photodynamic therapy.

PURPOSE: The aim of this study was to identify the changes in the primate visual system after a single session of photodynamic therapy (PDT) in an intact nonhuman primate retina. METHODS: As part of a larger study, PDT (wavelength 689 nm, 50 J/cm2, 600 mW/cm2, 83 seconds, 4-mm spot size) with verteporfin (6 mg/m2 intravenous infusion) was performed in one eye each of two cynomolgus monkeys. Fundus photography, fluorescein angiography (FA), indocyanine green angiography (ICG), optical coherence tomography (OCT), and multifocal electroretinography (mfERG) were performed at baseline and 12 time points (1-283 days) after PDT. In addition, retinal histopathologic findings were evaluated at 9 months. RESULTS: Various morphologic changes, including whitening of the treated area, RPE proliferation, closure of the choroidal vasculature, and subretinal edema (followed by foveolar thinning) were observed. Most of the changes persisted and were detectable in histopathologic evaluation at 9 months. Reductions of the mfERG amplitude, followed by varying degrees of recovery from the treated and the border regions, were observed. This was accompanied by progressive delay of P1 peak time up to 3 months after treatment, followed by complete recovery at 9 months. In addition, the nontreated area showed amplitude and timing mfERG deficits, which underwent gradual (but not complete) recovery. CONCLUSIONS: In a primate model, under standard clinical parameters, a single PDT treatment resulted in various dynamic morphologic and functional retinal changes detectable for up to 9 months after treatment. The significance of the observed changes and possible ways of pharmacologic interference with PDT adverse effects are discussed.

Animals↗

PubMed2006

Alveolar hemorrhage associated with platelet glycoprotein IIb/IIIa receptor inhibitors.

Platelet glycoprotein IIb/IIIa receptor inhibitors have been shown to improve outcomes in percutaneous coronary interventions. Their use with multiple anticoagulants has been associated with increased bleeding complications. Among these, alveolar hemorrhage is a rare and potentially fatal complication. Six patients with this complication were identified over a four-year period. Patient characteristics, possible risk factors, pathophysiology, prevention and potential treatment options are discussed.

Aged↗

PubMed2005

Population-based study of medical comorbidity in early dementia and "cognitive impairment, no dementia (CIND)": association with functional and cognitive impairment: The Cache County Study.

OBJECTIVE: Authors investigated medical comorbidity in persons with dementia and "Cognitive Impairment, No Dementia" (CIND). METHODS: The Cache County Study is an ongoing population-based study of the epidemiology of dementia, the risk factors for conversion from CIND to dementia, and the progression of dementia. As part of the study's first incidence wave, persons with dementia (N=149), CIND (N=225), or without cognitive impairment (N=321) were identified and studied. Participants received comprehensive clinical evaluations and were rated on the General Medical Health Rating (GMHR), a global measure of seriousness of medical comorbidity. Participants and informants also completed the Mini-Mental State Exam and provided self-report information about comorbid medical conditions and functioning in activities of daily living. RESULTS: There were few differences in number or type of comorbid medical conditions between persons with CIND and dementia, but persons with dementia were prescribed more medications. Stroke was more common in dementia participants, but other illnesses common in old age were not significantly different across cognitive groups. Medical comorbidity was more serious in both dementia and CIND, such that both groups were less likely to have "little to no" comorbidity. Seriousness of medical comorbidity was significantly associated with worse day-to-day functioning and cognition. CONCLUSIONS: Persons with CIND and dementia have more serious medical comorbidity than comparable persons without cognitive impairment. This comorbidity may play a role in the progression of CIND and dementia. Future studies should investigate the role of medical comorbidity and its treatment on dementia onset or progression, as well as the mechanisms mediating its neuropathologic effects.

Activities of Daily Living↗

PubMed2002

Distribution of brimonidine into anterior and posterior tissues of monkey, rabbit, and rat eyes.

The objectives of the study were to evaluate the distribution of brimonidine (alpha2-adrenergic agonist) into anterior and posterior ocular tissues. Single or multiple doses of a 0.2 or 0.5% brimonidine tartrate solution were administered to one or both eyes of monkeys or to one eye of rabbits. Brimonidine was administered intraperitoneally to rats. After topical administration, [14C]brimonidine was rapidly absorbed into the cornea and conjunctiva and distributed throughout the eye. [14C]Radioactivity was higher and cleared more slowly in pigmented tissues (iris/ciliary body, choroid/retina, and optic nerve) than in nonpigmented tissues. Single and multiple dosing led to a similar drug distribution, with higher levels of brimonidine measured in pigmented tissues after multiple dosing. Most of the radioactivity extracted from ocular tissues represented unchanged brimonidine. In the rabbits and the monkey treated in only one eye, levels of radioactivity in the untreated eye were low, consistent with the low systemic levels and rapid drug clearance. Posterior ocular tissue concentrations of radioactivity exceeded systemic blood concentrations. The vitreous humor brimonidine concentrations in monkeys treated topically with 0.2% brimonidine tartrate was 82 +/- 45 nM. Vitreous levels in rabbits confirmed the penetration of brimonidine to the posterior segment. Similar concentrations of brimonidine (22 to 390 nM) were measured in the vitreous and retina of rats injected intraperitoneally with brimonidine. Both topically applied and systemically administered brimonidine reach the back of the eye at nanomolar concentrations sufficient to activate alpha2-adrenergic receptors. The brimonidine levels achieved at the retina are relevant for neuroprotection models.

Administration, Topical↗

PubMed2002

The sestamibi scan as a preoperative screening tool.

Sestamibi scan is generally recognized in the literature to play a role in the imaging of parathyroid adenoma. Most institutions quote sensitivities ranging from 80 to 100 per cent. There is still a question as to whether patients need preoperative localization studies. Preoperative localization can potentially result in less invasive surgery, shorter operative times, decreased hospital stays, and decreased need for re-exploration. Our hypothesis is that the sestamibi scan is a sensitive predictor of parathyroid adenomas. The objectives of this study are to determine the sensitivity of sestamibi scan in detecting parathyroid adenoma, and to determine whether either parathyroid hormone (PTH) level or calcium level is an independent predictor of a positive scan. One hundred patients were retrospectively reviewed at Louisiana State University Health Sciences Center-Shreveport and Louisiana State University Health Sciences Center-Monroe from March 1993 through December 2000. All patients had a preoperative sestamibi scan. This scan was performed using the dual-phase technique in which the parathyroid glands are visualized after washout of tracer from the thyroid. The scan was followed by either a unilateral or bilateral neck dissection. There were 82 female patients and 18 male patients who ranged in age from 23 to 78 years. The median weight of glands with a positive scan was 795 mg. The median weight of glands with a negative scan was 480 mg. This difference was statistically significant (P < 0.04). Overall there were 107 adenomas. Of these 93 had positive scans and 14 had negative scans. This results in a sensitivity of 87 per cent. There were 67 glands that weighed at least 500 mg. Of these 67 glands 61 had positive scans and six had negative scans. This resulted in a sensitivity of 91 per cent. There were 40 glands that weighed less than 500 mg. Of these 40 glands 32 had positive scans and eight had negative scans. This resulted in a sensitivity of 80 per cent. Using multiple linear regression analysis calcium level correlated with the weight of the gland (P < 0.01). Calcium level also correlated with the PTH level (P < 0.01). However, neither the PTH level nor the calcium level correlated with a positive sestamibi scan. Sestamibi scan is a sensitive predictor for parathyroid adenoma greater than 500 mg (91% sensitivity). Even in smaller glands (<500 mg) 80 per cent sensitivity was demonstrated. Although the calcium level correlates with the PTH level neither PTH level nor calcium level is predictive of a positive sestamibi scan.

Adenoma↗