Biomedical subjects

S S AbiEzzi

Publications and source records attributed to S S AbiEzzi.

3 recordsLinked to original sources

PubMed1997

Decrease in fibronectin occurs coincident with the increased expression of its integrin receptor alpha5beta1 in stress-deprived ligaments.

Stress deprivation secondary to immobilization leads to atrophic changes in periarticular soft tissues. The changes in ligaments include a disorganization of collagen and cellular ultrastructure with varied biochemical alterations resulting in a functionally weaker tissue. This study tests the hypothesis that alterations in fibronectin (Fn) and the expression of its integrin receptor alpha5beta1 in ligament fibroblasts accompany the extracellular matrix remodeling which occurs in stress-deprived knee ligaments. The left knees of eighteen New Zealand white rabbits were surgically immobilized in acute flexion. Fibroblasts within three nine week and three twelve week stress-deprived anterior cruciate ligaments (ACLs) and medial collateral ligaments (MCLs) demonstrated markedly increased immunostaining for the beta1 and alpha5 integrin subunits, as compared to fibroblasts in the contralateral unoperated control ligaments. The effects of stress deprivation on the concentration of Fn was measured by competitive ELISA on the remaining twelve rabbits. Decreases in Fn of 54.0 percent and 63.7 percent occurred in the ACL after nine and twelve weeks of stress deprivation when compared to contralateral controls. The MCL had less of a decrease, losing 37.7 percent and 41.7 percent at nine and twelve weeks, respectively. These results suggest an important role for the Fn-specific integrin receptor alpha5beta1 in remodeling stress-deprived periarticular ligamentous tissue, and the importance of maintaining normal stresses on periarticular ligaments to prevent the degradation of extracellular matrix components such as Fn.

Animals↗

PubMed1995

Increased expression of the beta 1, alpha 5, and alpha v integrin adhesion receptor subunits occurs coincident with remodeling of stress-deprived rabbit anterior cruciate and medial collateral ligaments.

The biomechanical, biochemical, and morphological properties of the anterior cruciate and medial collateral ligaments are dramatically altered in response to deprivation of normal physical forces and joint motion. Integrin adhesion receptors are known to play important roles in the tissue remodeling that occurs in the course of normal wound repair. We propose that integrins play a similar role in the remodeling of the extracellular matrix in stress-deprived periarticular ligaments. This study tests the hypothesis that altered expression of integrins on ligament fibroblasts accompanies this remodeling. The left knees of 15 New Zealand White rabbits were surgically immobilized in acute flexion and the right knees served as controls (no operation). The anterior cruciate and medial collateral ligaments were harvested at 1, 3, 5, 9, or 12 weeks after immobilization. Sections from the ligaments were immunostained with monoclonal antibodies specific for the integrin subunits beta 1, alpha 5, alpha 6, and alpha v, as well as with a negative control antibody. Fibroblasts within both the stress-deprived anterior cruciate and medial collateral ligaments demonstrated markedly increased staining for the beta 1, alpha 5, and alpha v subunits, as compared with the controls. The increased staining was greatest at 9 weeks in the anterior cruciate ligament and at 12 weeks in the medial collateral ligament. Western blot study of ligament proteins extracted with sodium dodecyl sulfate demonstrated an increased amount of beta 1 subunit protein in both ligaments from knees that were stress deprived for 9 and 12 weeks, as compared with the control ligaments.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

The use of ultrasound for the diagnosis of soft-tissue masses in children.

Forty-four soft-tissue masses in 44 children (age range, 8 months to 18 years) were evaluated with high-resolution ultrasonography. Longitudinal and transverse images were obtained and interpreted within a classification scheme describing the masses as cystic, homogeneous solid, or mixed lesions. Diagnosis was confirmed surgically in all cases, allowing the accuracy of the ultrasound examination to be assessed. Of the 44 masses evaluated, 13 were cystic, 18 homogeneous solid, and 13 mixed masses. Ultrasound alone was independently diagnostic in 11 of 13 cystic masses (ganglions, Baker's cysts) and 12 of 18 homogeneous solid masses (foreign bodies). Ultrasound was useful but not independently diagnostic in six of 18 homogeneous solid masses and in 12 of 13 mixed solid masses and was misleading in three cases. Ultrasonography is a noninvasive, relatively low cost study, not involving radiation or sedation, that supplements the clinical examination and conventional radiography in the evaluation of musculoskeletal soft-tissue masses in children. It provides immediate characterization of mass size, consistency, and anatomic location. Ultrasonography is usually independently diagnostic in lesions such as cysts and foreign bodies and aids in clarifying the diagnosis of fibrous, cartilaginous, vascular, and lymphatic lesions.

Adolescent↗