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Biomedical subjects

R Burns

Publications and source records attributed to R Burns.

At least 91 records · Page 5Linked to original sources
PubMed1986

Radionuclide angiographic evaluation of ventricular function in isolated congenitally corrected transposition of the great arteries.

Eight asymptomatic patients (mean age 19 years, range 7 to 32) with congenitally corrected transposition of the great arteries (CCTGA) underwent equilibrium gated radionuclide angiocardiography at rest and during supine bicycle exercise to assess systemic (morphologic right) and pulmonary (morphologic left) ventricular function. Five patients had normal intracardiac hemodynamic values, 2 had trivial atrioventricular valve regurgitation and 1 patient had trivial pulmonary ventricular outflow tract obstruction. Average exercise duration was 11 +/- 1 minute, with limitation due only to fatigue. At peak exercise, heart rate increased 225% and systolic blood pressure 152% over the rest value. Pulmonary ventricular ejection fraction at rest was 51 +/- 3% (mean +/- standard error of the mean); it did not change significantly at peak stress, 53 +/- 2%. Systemic ventricular ejection fraction was 48 +/- 4% at rest and increased to 64 +/- 4% at peak exercise (p less than 0.01). Count-based volume changes for the pulmonary chamber showed no significant change in end-diastolic or systolic counts at peak exercise (109 +/- 8% and 106 +/- 9% of rest value, respectively). However, end-diastolic counts decreased 13% (87 +/- 3% of rest value) and end-systolic counts 34% (62 +/- 7% of rest value) at peak exercise in the systemic ventricle. These data suggest normal systemic and impaired pulmonary ventricular function in patients with congenitally corrected transposition of the great arteries unaccompanied by significant associated lesions. These findings have important clinical implications in the setting of complex congenital heart disease in patients in whom a morphologic right ventricle functions as the systemic pumping chamber. Despite the pulmonary ventricular dysfunction, symptoms were not apparent at rest or during exercise.

Adolescent↗
PubMed1986

Protein, DNA, and virus crystallography with a focused imaging proportional counter.

A set of programs has been developed for rapid collection of x-ray intensity data from protein and virus crystals with a commercially available two-dimensional focused geometry electronic detector. The detector is compact and portable, with unusually high spatial resolution comparable to that used in oscillation photography. It has allowed x-ray data collection on weakly diffracting crystals with large unit cells, as well as more conventional "diffractometer-quality" crystals. The quality of the data is compared with that from oscillation photography and automated diffractometry in the range of unit cells from 96.3 to 383.2 angstroms. Isomorphous and anomalous difference Pattersons, based on detector data, are shown for a variable surface glycoprotein mercury derivative and for a repressor-DNA bromine derivative, which has been solved at 7 angstroms with detector data only.

Computers↗
PubMed1986

Nifedipine tablet vs. hydralazine in patients with persisting hypertension who receive combined diuretic and beta-blocker therapy.

The antihypertensive effects of a 20 mg tablet of nifedipine were compared with those of hydralazine in a randomized, double-blind, placebo-controlled study. Nineteen patients with a diastolic blood pressure (BP) between 95 and 120 mm Hg despite combined diuretic and beta-blocker therapy completed the protocol. After 2 weeks of placebo each subject received increasing doses of nifedipine (20, 40, and 60 mg b.i.d.) and hydralazine (25, 50, and 100 mg b.i.d.) if tolerated or until goal BP (supine and standing diastolic BP less than 85 mm Hg) was achieved. Both nifedipine and hydralazine significantly lowered supine BP from placebo baseline (146 +/- 3/96 +/- 2 mm Hg) to 119 +/- 3/80 +/- 2 and 129 +/- 2/81 +/- 2 mm Hg, respectively. The decrease in systolic BP with nifedipine was significantly lower than that with hydralazine at 9 weeks. Neither drug significantly altered heart rate. Mean left ventricular ejection fractions were similar for nifedipine (67% +/- 2%), hydralazine (69% +/- 3%), and placebo (66% +/- 2%). The nifedipine tablet appears to be an effective antihypertensive agent in patients whose BP remains high despite combined diuretic and beta-blocker therapy.

Administration, Oral↗
PubMed1986

Nutritional assessment of community-living well elderly.

Nutritional assessment parameters were studied in a sample of 132 community-living well elderly. Results are presented for biochemical parameters of serum albumin, hemoglobin, and total lymphocyte count and anthropometric parameters of height, weight, mid-arm circumference, and triceps skinfold. The data show that, although there are some differences between age groups (young-old and old-old), all values remain well within normal limits established for younger individuals.

Aged↗
PubMed1985

A critical appraisal of impedance plethysmography in the diagnosis of acute deep venous thrombosis.

Compulsive performance of the test is paramount to obtaining good results. Sequential multiple tests with prolongation of the filling time to maximize venous filling and ultimately reaching a plateau is essential. Increase in venous filling by increasing the cuff pressure in the proximal lower thigh occluding cuff to 60 instead of 45 centimeters of water is helpful in obtaining optimum venous filling. Unrecognized patient apprehension or muscle contraction may be a reason for false-positive IPGs. Patient relaxation, local heat application or even electromyography attachment may be helpful. The IPG can be repeated after a few hours if a false-positive test result is suspected. If a test falls above the stop line, the NPV is so high that no repetition of the test is necessary and the limb is read out as showing no proximal venous thrombosis. If a test is normal or borderline, the test may be repeated with sequential testing until the test points seem to group together or a clear divergence of either normal or abnormal is achieved. If the contralateral limb is clearly normal and an abnormal test result is obtained in the suspected limb, the test is likely to be reliable. Bilateral abnormal IPGs, especially in the presence of congestive heart failure or severe edema, may indicate a false-positive test finding. Increased edema in the extremity decreases electrical resistivity and balancing the machine may become a technical problem.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1984

Difficulties in long term management of Parkinson's disease.

It must be recognised that patients with idiopathic Parkinson's disease will eventually get worse and, where appropriate, realistic prognostications of the future should be conveyed to patients and their responsible relatives. Some 15 per cent of patients will not respond to levodopa. When a patient does not show a significant improvement on therapy a number of important questions should be considered. Is the diagnosis correct? Consider an alternative diagnosis such as progressive supranuclear palsy, drug effect, multi infarct dementia, Alzheimer's disease, striatonigral degeneration, senile or essential tremor and the Shy-Drager syndrome which all may be mistaken for Parkinson's disease. Is the patient complying with therapy? Is the dose adequate and the frequency of administration appropriate? Are the symptoms caused by drug therapy? Would the addition of other therapy assist, for example amantadine, anticholinergics or bromocriptine? Is the patient on other drugs which may be contributing to the impaired function? Is the patient depressed? Is there some other underlying condition aggravating the Parkinson's disease?

Dementia↗
PubMed1984

McCune-Albright syndrome (fibrous dysplasia) associated with an orbital tumor.

Craniofacial fibrous dysplasia has rarely been described in the polyostotic form of McCune-Albright disease. The unique ophthalmic features of interest in this patient with McCune-Albright's disease was the presence of an orbital tumor that suddenly increased in size compressing the optic nerve. Prompt excision of the tumor resulted in restoration to normal vision.

Child↗
PubMed1983

Cell biology of hematoporphyrin derivative (HPD).

Tissue culture cells were treated with hematoporphyrin derivative (HPD) and analyzed for (1) HPD uptake, (2) HPD washout, and (3) fluorescence changes. The absorption peaks were the same for HPD in solution and HPD bound to cells. HPD was taken up by all cell types rapidly within the first 10 hours of exposure, and leveled off by 20 hours of exposure. HPD came out of all cell types to control levels by 72 hours after removal of the HPD bathing solution. The HPD appeared to come out of the malignant 3-T-12 cells more slowly than from the parental (non-malignant) 3-T-3 cells. The fluorescence spectrum of HPD-treated cells changed markedly from the time that the bathing HPD solution was removed from the cells. As time progressed the weakly fluorescent 590-nm peak increased greatly and the 615-nm and 630-nm peaks decreased significantly.

Animals↗
PubMed1983

Spontaneous dissection of the internal carotid artery.

Spontaneous dissection of the internal carotid artery has been considered a relatively rare cause of carotid artery occlusion. It is postulated this condition may not be uncommon and that some cases are not recognised. The condition is characterised by typical clinical and radiological features which should suggest the diagnosis. Despite these suggestive features it appears that recognition of this condition is not widespread and the diagnosis may not be made. Three cases of spontaneous dissection are reported. The clinical and radiological features will be emphasised and pathogenesis and treatment discussed.

Adult↗
PubMed1983

Identical twins with Alzheimer's disease.

Genetically proven identical twin sisters with Alzheimer's disease are reported. Both sisters at the age of fifty years developed a dementing illness. Their mother and maternal grandmother developed at the same age a similar illness. It is suggested that in some cases of familial Alzheimer's disease the condition is inherited by a single mutant gene.

Aged↗