Principal component and factor analysis to study variations in the aging lumbar spine.

Human spine is a multifunctional structure of human body consisting of bones, joints, ligaments, and muscles which all undergo a process of change with the age. A sudden change in these features either naturally or through injury can lead to some serious medical conditions which puts huge burden on health services and economy. While aging is inevitable, the effect of aging on different areas of spine is of clinical significance. This paper reports the growth and degenerative pattern of human spine using principal component analysis. Some noticeable lumbar spine features such as vertebral heights, disc heights, disc signal intensities, paraspinal muscles, subcutaneous fats, psoas muscles, and cerebrospinal fluid were used to study the variations seen on lumbar spine with the natural aging. These features were extracted from lumbar spine magnetic resonance images of 61 subjects with age ranging from 2 to 93 years. Principal component analysis is used to transform complex and multivariate feature space to a smaller meaningful representation. PCA transformation provided 2-D visualization and knowledge of variations among spinal features. Further useful information about correlation among the spinal features is acquired through factor analysis. The knowledge of age related changes in spinal features are important in understanding different spine related problems.

The effect of pulsed irrigation on the incidence of heterotopic ossification after total hip arthroplasty.

Heterotopic ossification (HO) is a common complication of total hip arthroplasty (THA). Pulsed lavage is being used with increasing frequency for THA. A prospective randomized, double-blind trial was initiated to determine if pulsed lavage affected the incidence of HO. A total of 94 THAs in 91 patients were analyzed. No significant difference in the incidence of HO was found between the 2 groups. Hypertrophic osteoarthritis was found to be a significant risk factor for HO. The findings suggest that the osteogenic precursor cells thought to be involved in the pathogenesis of HO possibly are derived from within the local soft tissues in the proximity of the hip joint.

CD44 isoform expression in synovial sarcoma correlates with epitheliogenesis but not prognosis.

AIMS: We immunohistochemically determined the expression of CD44 standard and splice variant isoforms in a series of synovial sarcomas and sought correlations with histological subtype and clinical parameters including outcome. METHODS AND RESULTS: From 39 patients, a total of 56 formalin-fixed and paraffin-embedded tumour samples (including initial, recurrent and metastatic tumours) were used to immunohistochemically evaluate the expression of epitopes encoded by CD44s and the CD44 splice variants CD44v3-v10. Significance of proposed prognostic indicators was evaluated in relation to the survival, time to local recurrence and time to metastases using log-rank analysis. Sixty-four percent of synovial sarcomas expressed CD44s and 46% expressed CD44v3-v10 (var). Synovial sarcomas with epithelial or epithelioid areas preferentially expressed CD44s in these areas when compared with the spindle cell element. There were no correlations with clinical parameters or outcome. CONCLUSION: The expression of CD44 was not found to correlate with survival, local recurrence or metastatic ability. In synovial sarcoma, CD44 and variant isoform expression appears to be associated with the degree of epithelial differentiation. CD44 expression in synovial sarcoma shows interesting similarities to CD44 expression in embryological epitheliogenesis.

The normal structure and function of CD44 and its role in neoplasia.

CD44 is a transmembrane glycoprotein, the variant isoforms of which are coded for by alternative splicing, with the most prolific isoform being CD44 standard. CD44 is found in a wide variety of tissues including the central nervous system, lung, epidermis, liver, and pancreas, whereas variant isoforms of CD44 (CD44v) appear to have a much more restricted distribution. Variants of CD44 are expressed in tissues during development, including embryonic epithelia. Known functions of CD44 are cellular adhesion (aggregation and migration), hyaluronate degradation, lymphocyte activation, lymph node homing, myelopoiesis and lymphopoiesis, angiogenesis, and release of cytokines. The functions of CD44 are principally dependant on cellular adhesion in one setting or another. The role of CD44 in neoplasia is less well defined, although metastatic potential can be conferred on non-metastasising cell lines by transfection with a variant of CD44 and high levels of CD44 are associated with several types of malignant tumours. The physiological functions of CD44 indicate that the molecule could be involved in the metastatic spread of tumours. Many studies have investigated the pattern of CD44 distribution in tumours and some observations suggest that certain cells do not use CD44 in tumorigenesis or in the production of metastases. However, the data are extremely conflicting, and further studies are needed to establish the prognostic value of CD44 and its variant isoforms. The precise function of CD44 in the metastatic process and the degree of involvement in human malignancies has yet to be established fully.