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Biomedical subjects

C E Murphy

Publications and source records attributed to C E Murphy.

31 records · Page 2Linked to original sources
PubMed1986

Papillary-annular continuity and left ventricular systolic function after mitral valve replacement.

The contribution of the subvalvular apparatus to left ventricular function was evaluated in a canine preparation that allowed variation of subvalvular tethering forces after mitral valve replacement. Ten normal dogs were instrumented with micromanometer-tipped pressure catheters in the left ventricle and left atrium and piezoelectric sonomicrometry crystals to measure left ventricular major-axis, minor-axis, and wall thickness dimension changes. After control data were obtained, each dog underwent cardiopulmonary bypass and the mitral valve was replaced with a St. Jude bileaflet valve (No. 23 or 25). The native valve was completely excised and all chordal attachments were severed at the head of each papillary muscle. A 3-0 prolene suture was passed through the head of each papillary muscle, gently tied over a pair of felt pledgets, and exteriorized in a paravalvular manner that allowed both "attached" and "detached" states to be studied in a randomized manner 1 hr after release of the aortic cross-clamp. A significant (p less than .05) increase in major-axis length from control was observed in the detached state at both end-diastole and end-systole when compared at matched left ventricular end-diastolic pressures. Systolic function measured by load-dependent variables at matched end-diastolic lengths was higher in the detached state. However, when systolic function was examined by load-independent variables such as the slope of the stroke work end-diastolic length relationship, the slope of the end-systolic pressure-volume relationship, or the stroke work end-diastolic volume relationship, no statistically significant difference could be detected between states of papillary-annular continuity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

The efficacy of blood versus crystalloid coronary sinus cardioplegia during global myocardial ischemia.

The efficacy of blood and crystalloid retrograde cardioplegia in protecting the ischemic myocardium was compared. Seventeen dogs underwent 2 hr of global myocardial ischemia while on cardiopulmonary bypass. Crystalloid (in nine dogs) or blood (in eight dogs) cardioplegic solution was infused continuously into the coronary sinus. Left and right ventricular function were assessed before ischemia and after 30 and 60 min of reperfusion by means of highly sensitive, load-independent index of contractility (the slope of the stroke work vs end-diastolic length relationship). Ventricular biopsies for ATP determination were obtained before ischemia, at the end of ischemia, and after 60 min of reperfusion. Left and right ventricular function returned to normal after 60 min of reperfusion in both groups. Left ventricular ATP remained unchanged, whereas small but significant decreases in right ventricular ATP were observed after 60 min of reperfusion in both groups. Thus continuous crystalloid or blood retrograde coronary sinus cardioplegia in dogs preserved myocardial function and metabolism equally well after 2 hr of global cardiac ischemia.

Adenosine Triphosphate↗
PubMed1983

Myocardial adenosine triphosphate levels during early sepsis.

Myocardial adenosine triphosphate (ATP) levels were determined in rats given sepsis by cecal ligation. Determinations were made after a set time interval, prior to the onset of obtundent effects and immobility, in an attempt to avoid the well-documented, deleterious influence of hypoperfusion status. The absence of a low perfusion state at the time of myocardial biopsy was confirmed by the maintenance of simultaneously determined peripheral organ ATP levels. Myocardial ATP levels were significantly elevated in two groups of septic rats, one minimally hydrated and the other actively hydrated intravenously (IV), when compared with either controls that had not been operated on or animals that underwent sham operations and were IV hydrated. The relationship between elevated myocardial ATP levels and functional status during sepsis deserves further investigation.

Adenosine Triphosphate↗
PubMed1983

Environmental tritium transport from an atmospheric release of tritiated water.

Elevated tritium levels were found in samples of pine needles and surface leaf litter taken along the path of an atmospheric tritiated water release from the Savannah River Plant, Aiken, South Carolina. After the initial exposure period, tritium levels declined to background within 3 days. The equilibration half-time for tritium in terrestrial ecosystems is much shorter after exposure to tritiated water than after an exposure to molecular tritium. This difference is due to preferential deposition of molecular tritium in soil.

Air Pollution, Radioactive↗
PubMed1980

Mannosidosis: patterns of storage and urinary excretion of oligosaccharides in the bovine model.

Mannose and glucosamine-containing oligosaccharides were extracted from tissues of variously aged calves with mannosidosis. Whereas storage in the brain, and to a lesser extent in the pancreas and lymph nodes, was cumulative, that in the liver was relatively stable over the time period followed. It is suggested that in this latter organ the 15--20% residual alpha-mannosidase activity attributable to the mutant enzyme might be sufficient to normalise function. In the kidney, levels actually fell over the first 15--20 weeks of life and thereafter remained constant. It is postulated that, in foetal life, storage is cumulative but, after birth, storage material is lost from the kidney into the urine by degeneration and/or desquamation of renal tubular cells. From 20 weeks the amount lost is in equilibrium with that formed or absorbed by the tubular cells.

Animals↗
PubMed1976

Enzyme replacement therapy--an experiment of nature in a chimeric mannosidosis calf.

Enzyme replacement therapy was studied in a chimeric mannosidosis calf which had received a natural transplacental transplant of normal lymphocytes from its co-twin. There was considerable reduction in the pathology of certain organs and in the amount of storage oligosaccharides, but the clinical course of this neurologic disease was not significantly altered. It was postulated that if this disease had been purely visceral the transplant would have been relatively effective.

Animals↗
PubMedDate not supplied

The effect of cyclosporine, total lymphoid irradiation, and cobra venom factor on hyperacute rejection.

Transplantation into sensitized recipients is contraindicated due to the potential for hyperacute rejection. In order to study the mechanism of hyperacute rejection and the role of immunosuppression in the face of presensitization, we evaluated the effect of total lymphoid irradiation, cyclosporine, and cobra venom factor, alone and in combination, on hyperacute rejection of heterotopic rat heart allografts. Lewis rats were sensitized to strongly RT-1-incompatible ACI rats by three successive skin grafts. Heart allografts were then performed, and survived for a mean period of 15.7 +/- 7.4 hours. Neither preoperative treatment of hypersensitized rats with total lymphoid irradiation alone nor with cyclosporine (5 mg/kg/day) resulted in a prolongation of survival (20.4 +/- 16.6 hours and 35.6 +/- 6.2 hours, respectively). However, complement depletion using cobra venom factor significantly prolonged mean graft survival time to 114.4 +/- 31.0 hours (p less than 0.05). Cyclosporine (10 mg/kg/day) also significantly prolonged survival to 149 +/- 29 hours (p less than 0.01), but did not lower the antibody or complement levels. The addition of total lymphoid irradiation or cyclosporine to treatment with cobra venom factor did not result in longer survival than cobra venom factor alone. In conclusion, cobra venom factor and cyclosporine delay but do not prevent hyperacute rejection, while total lymphoid irradiation has no observable effect on hyperacute rejection.

Animals↗