A A Pitsillides — Page 3

PubMedDate not supplied

Acromial spur formation in patients with rotator cuff tears.

In this study we analyzed the acromial spurs of 15 patients with impingement syndrome undergoing open rotator cuff repair. Mineral apposition analysis and quantitative cytochemical techniques for glucose-6-phosphate dehydrogenase (G6PD) activity (pentose phosphate pathway), alkaline phosphatase (ALP) activity (osteoblast activity), and tartrate-resistant acid phosphatase (TRAP) activity (osteoclast phenotype) were used to examine the distribution and level of activity of selected marker enzymes within the acromial spur insertion into the coracoacromial ligament in order to establish whether local behavior of bone cells is consistent with the proposed secondary development of the acromial spur. Our results indicate that G6PD and ALP activity was higher in osteoblasts on the inferior surface compared with the superior surface of the acromial spur in all patients (P <.001). This area correlated to the most intense area of mineral apposition shown by dual tetracycline labeling. TRAP activity revealed a heterogeneous distribution within the samples. A greater G6PD activity per cell (mean increase of 87%) was seen at the tip compared with that in post- and pre-tip zones within the coronal plane (P <.0002). The qualitative and quantitative enzyme analyses show that the acromial insertion of the coracoacromial ligament is actively involved in bone turnover. The spatial distribution patterns of metabolically active bone-forming osteoblastic cells compared with a heterogeneous distribution of TRAP-positive osteoclasts provide evidence of bone remodeling consistent with the morphologic contours of the acromial enthesis. The sites of oxytetracycline labeling appear to correlate with the sites of high ALP and G6PD activity, which supports the concept of spur formation being a secondary phenomenon in the presence of established rotator cuff tears.

Acid Phosphatase↗

PubMedDate not supplied

[The cellular aspects of the development of synovial joints and articular cartilage].

There have been many reports on the histological development of mammalian diarthrodial or synovial joints. While these are useful for comparative purposes, they tell us little of the cellular basis of joint morphogenesis which must underlie a number of morphogenetic defects. The process of joint morphogenesis is complex and can be subdivided into a number of facets and this report will focus on 2 of them. First, the process of joint cavitation in the chick metatarsophalangeal joint, where we propose that the selective secretion of hyaluronan into the presumptive cavity plays a central role. Secondly, the development of articular cartilage where we have used the South American opossum Monodelphis domestica as a model for mammalian development. Like most marsupials, the young are born at a much earlier developmental stage than eutherian mammals. Using antibodies which detect proliferating chondrocytes and those synthesizing insulin-like growth factors 1 and 2 and insulin-like growth factor 1 binding protein, we report that the majority of growth (as assessed by these indicators) appears appositional.

Animals↗