John E. Speich

Mechanical Engineering   601 West Main Street   Room 310   Richmond, VA 23284-3015	Tel: 804-827-7036 Fax: 804-827-7030 E-mail: jespeich@vcu.edu
Web: http://www.egr.vcu.edu/me/faculty/me-faculty_speich.html
Research: Developing robotic devices for medical applications

BBSI project:Experimental Characterization of Strain Softening and Viscoelastic Behavior in Bladder Smooth Muscle
Urinary bladder undergoes repetitive and extensive lengthening-contracting cycles during normal physiological activity. Bladder is never fully "at rest"; even during lengthening (filling), bladder smooth muscle (detrusor) produces low-amplitude rhythmic contractions that exert an internal load to complement the external load occurring during bladder filling. Detrusor also displays length-dependent regulation of myosin light chain (MLC) phosphorylation (1), a key player in muscle activation. Although preconditioning is present in bladder (2), whether the loss of stiffness is caused purely by viscoelastic effects, or also due to strain softening, remains to be determined. For these reasons, a more thorough understanding of preconditioning in detrusor is warranted.

The present study is designed to test the hypothesis that detrusor preconditioning involves elements of both viscoelastic (reversible) and strain softening, but that strain softening is reversible upon muscle activation. Additionally, this study will determine to what degree detrusor cellular proteins contribute to preconditioning. The experimental protocol will use an electromechanical lever to stretch strips of rabbit detrusor and measure the length-tension characteristics at various levels of muscle activation. The overall goal of this research is to develop a better understanding of the behavior of bladder smooth muscle, which could lead to the identification of drugs to treat overactive bladder and incontinence.

References
1. Ratz, P. H., and Miner, A. S. (2003) Length-dependent regulation of basal myosin phosphorylation and force in detrusor smooth muscle. Am J Physiol 284, R1063-R1070.

2. Minekus, J., and van Mastrigt, R. (2001) Length dependence of the contractility of pig detrusor smooth muscle fibres. Urol Res 29, 126-133.

Other Research Interests (see web page for more details)

• Developing robotic devices for medical applications
    o Robotic devices for delivering rehabilitation therapy
    o Robot-assisted surgery
    o Robotic devices to aid persons with disabilities
  
• Telemanipulation - especially scaled bilateral telemanipulation
  
• Human-robot interaction and haptic interfaces
  
• Compliant-mechanism-based robots and devices

   

  
  

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