東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back

Switch To: Labeled | MARC Mode | ISBD

Sarcomere dynamics during contractio...

University of Michigan.

Linked to FindBook

Google Book

Amazon

博客來

Sarcomere dynamics during contraction-induced injury to permeabilized single muscle fibers.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Sarcomere dynamics during contraction-induced injury to permeabilized single muscle fibers./
Author:	Panchangam, Appaji.
Description:	109 p.
Notes:	Adviser: John A. Faulkner.
Contained By:	Dissertation Abstracts International69-03B.
Subject:	Biology, Physiology. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoeng/servlet/advanced?query=3305057
ISBN:	9780549512363

Sarcomere dynamics during contraction-induced injury to permeabilized single muscle fibers.
Panchangam, Appaji.

Sarcomere dynamics during contraction-induced injury to permeabilized single muscle fibers. - 109 p.

Adviser: John A. Faulkner.

Thesis (Ph.D.)--University of Michigan, 2008.

A contraction-induced injury results when an activated skeletal muscle or a single fiber is stretched in a 'lengthening contraction'. This type of injury to muscle fibers is a leading cause of the loss of mobility that is associated with old age. Manifestations of the injury revealed by electron microscopy show focally disrupted single sarcomeres, or small groups of sarcomeres, that are surrounded by intact sarcomeres. The purpose of this dissertation was to study the dynamic behavior of sarcomeres during lengthening contractions of single muscle fibers. The working hypothesis was that contraction-induced injury occurs during a lengthening contraction when sarcomeres undergo elongation at varying rates and those lengthened at the highest rates reach longer lengths and are damaged. To test this hypothesis, a laser scanning system was developed that recorded rapidly (500 s-1) the lengths of sarcomeres contained in each of 20 contiguous regions along &sim;1 mm segments of a fiber. The fiber segments were obtained from soleus muscles of adult male rats and the membranes of the fibers were permeabilized chemically. The experiments performed with the laser scanning apparatus, indicated that: (i) during a lengthening contraction, the regions of fibers that contain the longer sarcomeres at the onset of the lengthening elongate more compared with the regions that contain shorter sarcomeres; (ii) lengthening contractions increased the variability in the lengths of sarcomeres in relaxed fibers; and (iii) during a lengthening contraction, within any given fiber region, the rate of elongation of sarcomeres was stable, but different regions stretched at different rates as the contraction proceeded. The present findings support the hypothesis that, within single fibers, non-uniformities develop in the lengths of sarcomeres that are increased by a lengthening contraction. The finding that all fiber regions elongate at stable rates during lengthening contractions contradicts a previous hypothesis that during lengthening contractions, the longest sarcomeres undergo rapid and sudden elongation to extreme lengths. The conclusion is that during lengthening contractions, the longer sarcomeres in series with shorter sarcomeres undergo elongation at higher velocities and upon return to original length, structural elements within some of these longer sarcomeres are functionally compromised.

ISBN: 9780549512363Subjects--Topical Terms:

1017816
Biology, Physiology.

Sarcomere dynamics during contraction-induced injury to permeabilized single muscle fibers.
LDR:03326nam 2200289 a 45 001 856670
005 20100709
008 100709s2008 ||||||||||||||||| ||eng d
020 $a 9780549512363
035 $a (UMI)AAI3305057
035 $a AAI3305057
040 $a UMI $c UMI
100 1 $a Panchangam, Appaji. $3 1023511
245 1 0 $a Sarcomere dynamics during contraction-induced injury to permeabilized single muscle fibers.
300 $a 109 p.
500 $a Adviser: John A. Faulkner.
500 $a Source: Dissertation Abstracts International, Volume: 69-03, Section: B, page: 1767.
502 $a Thesis (Ph.D.)--University of Michigan, 2008.
520 $a A contraction-induced injury results when an activated skeletal muscle or a single fiber is stretched in a 'lengthening contraction'. This type of injury to muscle fibers is a leading cause of the loss of mobility that is associated with old age. Manifestations of the injury revealed by electron microscopy show focally disrupted single sarcomeres, or small groups of sarcomeres, that are surrounded by intact sarcomeres. The purpose of this dissertation was to study the dynamic behavior of sarcomeres during lengthening contractions of single muscle fibers. The working hypothesis was that contraction-induced injury occurs during a lengthening contraction when sarcomeres undergo elongation at varying rates and those lengthened at the highest rates reach longer lengths and are damaged. To test this hypothesis, a laser scanning system was developed that recorded rapidly (500 s-1) the lengths of sarcomeres contained in each of 20 contiguous regions along &sim;1 mm segments of a fiber. The fiber segments were obtained from soleus muscles of adult male rats and the membranes of the fibers were permeabilized chemically. The experiments performed with the laser scanning apparatus, indicated that: (i) during a lengthening contraction, the regions of fibers that contain the longer sarcomeres at the onset of the lengthening elongate more compared with the regions that contain shorter sarcomeres; (ii) lengthening contractions increased the variability in the lengths of sarcomeres in relaxed fibers; and (iii) during a lengthening contraction, within any given fiber region, the rate of elongation of sarcomeres was stable, but different regions stretched at different rates as the contraction proceeded. The present findings support the hypothesis that, within single fibers, non-uniformities develop in the lengths of sarcomeres that are increased by a lengthening contraction. The finding that all fiber regions elongate at stable rates during lengthening contractions contradicts a previous hypothesis that during lengthening contractions, the longest sarcomeres undergo rapid and sudden elongation to extreme lengths. The conclusion is that during lengthening contractions, the longer sarcomeres in series with shorter sarcomeres undergo elongation at higher velocities and upon return to original length, structural elements within some of these longer sarcomeres are functionally compromised.
590 $a School code: 0127.
650 4 $a Biology, Physiology. $3 1017816
650 4 $a Engineering, Biomedical. $3 1017684
650 4 $a Health Sciences, Rehabilitation and Therapy. $3 1017926
690 $a 0382
690 $a 0541
690 $a 0719
710 2 $a University of Michigan. $3 777416
773 0 $t Dissertation Abstracts International $g 69-03B.
790 $a 0127
790 1 0 $a Faulkner, John A., $e advisor
791 $a Ph.D.
792 $a 2008
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoeng/servlet/advanced?query=3305057