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16. Blood Pumps Constructed from Skeletal Muscle.

Author

Cooper, David K. C., Miller, Leslie W., Patterson, G. Alexander, Greer, K. A., Anderson, D. R., and Stephenson, L. W.

Abstract

Skeletal muscle is capable of transforming chemical energy into mechanical energy with extraordinary efficiency. We and others have shown that skeletal muscle has the capacity to become fatigue-resistant and to adapt to new patterns of work. These changes occur when skeletal muscle is subjected to low-frequency electrical stimulation for a period of several weeks. [ABSTRACT FROM AUTHOR]

Published
1996
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34. In vivo 31P-NMR spectroscopy of chronically stimulated canine skeletal muscle

Author

Clark, B. J., Acker, M. A., McCully, K., Subramanian, H. V., Hammond, R. L., Salmons, S., Chance, B., and Stephenson, L. W.

Abstract

Chronic stimulation converts skeletal muscle of mixed fiber type to a uniform muscle made up of type I, fatigue-resistant fibers. Here, the bioenergetic correlates of fatigue resistance in conditioned canine latissimus dorsi are assessed with in vivo phosphorus-31 nuclear magnetic resonance (31P-NMR) spectroscopy. After chronic electrical stimulation, five dogs underwent 31P-NMR spectroscopic and isometric tension measurements on conditioned and contralateral control muscle during stimulation for 200, 300, 500, and 800 ms of an 1,100-ms duty cycle. With stimulation, phosphocreatine (PCr) fell proportional to the degree of stimulation in both conditioned and control muscle but fell significantly less in conditioned muscle at all but the least intense stimulation period (200 ms). Isometric tension, expressed as a tension time index per gram muscle, was significantly greater in the conditioned muscle at the two longest stimulation periods. The overall small change in PCr and the lack of a plateau in tension observed in the conditioned muscle are similar to that seen in cardiac muscle during increased energy demand. This study indicates that the conditioned muscle's markedly enhanced resistance to fatigue is in part the result of its increased capacity for oxidative phosphorylation.

Published
1988
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35. Spontaneous right ventricular rupture after sternal dehiscence: a preventable complication?

Author

Arbulu, A, Gursel, E, Camero, L G, Asfaw, I, and Stephenson, L W

Abstract

Mediastinitis and/or sternal dehiscence developed in 143 out of 10,263 patients (1.4%) who underwent cardiac surgery between January 1979-December 1993. Mediastinal drainage, sternal debridement and early wound closure with pectoralis major and/or rectus abdominalis muscle flaps was the treatment employed. Between these two stages of treatment, massive hemorrhage developed in seven patients (0.07%) from a tear of the anterior wall of the right ventricle (RV). Six patients survived. Temporary control of the bleeding was achieved with digital or full palm pressure control of the ventricular tear. This was followed by immediate repair in the operating room (OR). The only death was due to exsanguination in the intensive care unit. The other six patients were taken to the OR. The anterior RV was freed from the underside of the sternum and the RV tear repaired with or without the aid of femoral-femoral bypass. These six then had muscle flap wound closures at that time or shortly after. All six were hospital survivors and are currently alive. We believe that RV rupture results from the sternal edges pulling the anterior surface of the RV apart, since the RV is stuck to the underside of the sternum. This experience indicates that the RV must be freed in all cases during initial sternal debridement. Hopefully this simple maneuver will prevent this horrendous complication.

Published
1996
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38. Splenosis.

Author

STEPHENSON, LARRY W., LEONARD, ROBERT P., LONGINO, LUTHER A., Stephenson, L W, Leonard, R P, and Longino, L A

Published
1975

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