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Biomedical subjects

K Dowling

Publications and source records attributed to K Dowling.

27 records · Page 2Linked to original sources
PubMed1980

Direct metabolic effects of isoproterenol and propranolol in ischemic myocardium of the dog.

The effect of either isoproterenol or propranolol on the metabolism of ischemic myocardium was examined. To ensure that all changes were due to changes in metabolism and not drug-induced changes in residual flow to the ischemic regions, we devised a preparation in which two coronary branches on the same heart were simultaneously perfused at a low flow rate. Microsphere measurements verified that the two ischemic regions were receiving identical blood flow rates. One branch received an infusion of 0.9% NaCl and the other received the drug. After 1 h both regions were biopsied and the high-energy phosphate levels in each region were determined. ATP and phosphocreatine each fell to about 50% of their starting values in the 0.9% NaCl-treated regions, and isoproterenol did not further depress the high-energy phosphate concentrations. Propranolol, on the other hand, significantly preserved the high-energy phosphate concentrations. We conclude that although isoproterenol seemed incapable of accelerating energy utilization in ischemic myocardium, propranolol is apparently capable of reducing it.

Adenosine Triphosphate↗
PubMed1979

The failure of hydrogen peroxide to improve function in ischemically depressed myocardium.

The hypothesis that hydrogen peroxide might lend inotropic support to ischemically depressed myocardium was critically tested in a canine model. A coronary branch was perfused at reduced flow to depress mechanical function. Since hydrogen peroxide infusion into the perfusate failed to alter the segment's contractile force, it was concluded that the previously described beneficial effects of hydrogen peroxide infusions are probably not related to a restoration of contractility in ischemic myocardium.

Animals↗
PubMed1979

Smooth-pursuit eye movements in the newborn infant.

The capacity of newborn infants to smooth-pursuit eye movements in single-target tracking and in optokinetic nystagmus to a moving striped field was examined utilizing DC electrooculography. Smooth-pursuit movements were observed in all infants who were alert during testing, but they occupied less than 15% of viewing time during single-target tracking. The velocity of smooth-pursuit segments in single-target tracking increased linearly to a target velocity of 19 degrees/sec and deteriorated rapidly at faster speeds. No smooth pursuit occurred above 32 degrees/sec in single-target tracking. By contrast, optokinetic nystagmus was observed at all field velocities to 40 degrees/sec, but the speed of the mean slow component increased linearly to 25 degrees/sec and diminished above that field velocity. Infant optokinetic nystagmus differed strikingly from that of adults in that tonic ocular deviation was in the direction of field movement rather than away from it. This feature of neonatal optokinetic nystagmus is consistent with deficient foveal function and suggests that the relatively poor smooth-pursuit performance of newborns may be related to foveal immaturity.

Electrooculography↗
PubMedDate not supplied

Management of failing prosthetic bypass grafts with metallic stent placement.

PURPOSE: To evaluate the role of metallic stents in treating stenoses involving prosthetic arterial bypass grafts. METHODS: Patients undergoing stent placement within a failing prosthetic bypass graft, during a 41-month period, were reviewed for treatment outcome and complications. The indications for stent placement in 15 patients included severe claudication (n = 3), rest pain (n = 9), and minor or major tissue loss (n = 3). Lesions were at the proximal anastomosis (n = 6), the distal anastomosis (n = 3), or within the graft (n = 6). RESULTS: Treatment with metallic stents was successful in all patients. There was one acute stent thrombosis, successfully treated with thrombolytic therapy. Follow-up data are available for a mean duration of 12.3 months. The mean duration of primary patency was 9.4 months with 6- and 12-month primary patency rates of 51.9% and 37.0%, respectively. The mean duration of secondary patency was 12.1 months with 6- and 12-month secondary patency rates of 80.0% and 72.7%, respectively. Two patients with discontinuous runoff and preexisting gangrene required a below-knee amputation. Six patients were revised surgically after stent placement (at a mean of 10.8 months). Three late deaths occurred during follow-up. CONCLUSION: Given the mortality risks of surgical revision and the reduced life expectancy of this patient population, metallic stent placement represents a viable, short-term treatment option for stenoses within or at the anastomoses of prosthetic grafts. Further evaluation is warranted to compare intragraft stent placement with surgical graft revision.

Adult↗
PubMedDate not supplied

Should I accept or reject my assignment?

This article examines the implications of one's decision to accept or reject a nursing assignment and presents alternatives to achieving equitable nursing assignments.

American Nurses' Association↗