Biomedical subjects

K Hsi

Publications and source records attributed to K Hsi.

3 recordsLinked to original sources

PubMed1988

Trauma in the elderly.

One hundred geriatric patients who suffered injury severe enough to necessitate hospitalization were compared retrospectively to a random group of 100 younger patients. The elderly suffered different types of injury and died six times as often as their younger peers, even when controlled for injury severity. The PRE method was employed to examine outcome in both groups and was found to be strongly predictive of death in young patients. Age stratification aided significantly in predicting mortality in elderly patients. Regression analysis was employed to examine the data set to determine the relative importance of several variables in the prediction of ultimate mortality. By incorporating all the data from the entire data set, curves describing the contribution of age and shock to mortality corrected for all factors is possible. Increasing age after 65 increases mortality and this effect is dramatically increased by the presence of shock. This information may be useful in counselling the injured elderly and their families.

Adolescent↗

PubMed1987

Stereological analysis of the muscle-tendon junction in the aging mouse.

Transmission of contractile tension from skeletal muscle fibers to connective tissue elements is thought to occur at the muscle-tendon junctions, specialized regions at the extreme ends of the fibers. Previous stereological studies on adult mouse and chicken fibers have shown that, with reference to equal cross-sectional areas of myofibrils, the muscle-tendon junctions of faster fibers have significantly more surface membrane devoted to force transmission than do those of slower fibers (Trotter et al.: Anat. Rec. 213:16-25, 1985a; Trotter et al.: Anat. Rec. 213:26-32,1985b; Trotter and Baca: Anat. Rec. 218:256-266, 1987). In the present study we have analyzed the muscle-tendon junctions of 30-month-old mice, employing techniques for scanning and transmission electron microscopy and for ultrastructural stereology which are identical to those previously used to study the same muscles in 4-month-old mice. Whereas the principal structural features of the muscle-tendon junctions of fibers from adult and aged mice are indistinguishable, stereological analyses of the fiber-tendon interfaces indicate that, in aging animals, the interfacial ratio (the ratio of the surface area of force-transmitting membrane to the cross-sectional area of force-generating myofibrils) is significantly reduced. While the interfacial ratio of fast-twitch fibers of the adult plantaris is about 14.5, the corresponding ratio in aged animals is about ten. In the predominantly slow-twitch fibers of the adult soleus, the interfacial ratio is about ten at the insertion and about 12.7 at the origin, whereas the corresponding ratios in the aged animals are both about ten.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1985

A morphometric analysis of the muscle-tendon junction.

Transmission of the contractile force produced by skeletal muscle fibers from myofilaments to tendon fibers occurs at the muscle-tendon junction. This interface between muscle and tendon is characterized by an amplification of the membrane area across which force is transmitted, with the result that stress at the muscle-tendon interface is less than it would be if the muscle fiber ended without surface folding. The amount of stress reduction is proportional to the degree of surface amplification. Because an understanding of the mechanical properties of the muscle-tendon junction requires a quantitative appreciation of the amplification of interfacial area, and hence the reduction of stress, produced by membrane elaboration at the muscle-tendon junction, we have developed a reliable morphometric approach for quantifying this surface amplification. The approach reported here makes use of point-counting techniques applied to thin sections of murine muscle-tendon junctions, together with a statistical analysis of the data. The results indicate that the load on the cell membrane at the muscle-tendon junction is reduced approximately 1 order of magnitude by membrane amplification, compared to the load calculated to occur if the muscle fiber ended as a right cylinder. In addition, significant differences in the degree of membrane amplification have been detected among the four muscle-tendon junctions analyzed in this study. These results and methods should prove useful in future analyses of normal and abnormal muscle-tendon junctions.

Analysis of Variance↗