Chondroitin‐6‐sulfate incorporation and mechanical stimulation increase MSC‐collagen sponge construct stiffness

Using functional tissue engineering principles, our laboratory has produced tendon repair tissue which matches the normal patellar tendon force‐displacement curve up to 32% of failure. This repair tissue will need to withstand more strenuous activities, which can reach or even exceed 40% of failure force. To improve the linear stiffness of our tissue engineered constructs (TECs) and tissue engineered repairs, our lab is incorporating the glycosaminoglycan chondroitin‐6‐sulfate (C6S) into a type I collagen scaffold. In this study, we examined the effect of C6S incorporation and mechanical stimulation cycle number on linear stiffness and mRNA expression (collagen types I and III, decorin and fibronectin) for mesenchymal stem cell (MSC)‐collagen sponge TECs. The TECs were fabricated by inoculating MSCs at a density of 0.14 × 10⁶ cells/construct onto pre‐cut scaffolds. Primarily type I collagen scaffold materials, with or without C6S, were cultured using mechanical stimulation with three different cycle numbers (0, 100, or 3,000 cycles/day). After 2 weeks in culture, TECs were evaluated for linear stiffness and mRNA expression. C6S incorporation and cycle number each played an important role in gene expression, but only the interaction of C6S incorporation and cycle number produced a benefit for TEC linear stiffness. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1092–1099, 2010     

Expressive writing reduces avoidance and somatic complaints in a community sample with constraints on expression

Design and methods. This experimental study examined expressive writing (EW) in a community sample with social constraints on self‐expression. Gay men (N = 62) were assigned randomly to describe gay‐related thoughts and feelings (EW) or to write objectively (CTRL). Self‐reported symptoms and physician visits were assessed at baseline and 1‐ and 2‐month follow‐ups. Results. Significant Group×Time interaction for somatic symptoms indicated buffering effect of EW. EW reduced gay‐related avoidance, relative to CTRL. Avoidance and symptom changes were significantly, positively associated. Conclusions. Consistent with inhibition theory, EW reduces chronic avoidance and buffers stress‐related physical symptoms in stigmatized groups.     

Health status of children in self-care

Are children in self-care more obese, do they miss more school days, and do they make more visits to the school health office than children not in self-care? We undertook a cross-sectional survey of students in ten public elementary schools in Tucson over a two-year period in an attempt to answer these questions. The sample included 503 fifth-grade students, 137 in self-care and 366 not in self-care. Demographic information and data on school absences were obtained from school records. Physical examinations were performed at school. Obesity was assessed using the body mass index calculation, in which body mass index = (body weight in kilograms)/(height in meters). Every visit to the school health office during the 1985-1986 and 1986-1987 school years was recorded for each child. There were no differences in age between those in the self-care and adult-care groups. Boys were more likely to be in self-care, as were non-Hispanic children. There were no differences in weight, body mass index, school days missed, or visits to the school health office between children in self-care and those in adult care. Our findings suggest that, by the criteria used in this study, 11-year-old children in self-care do not suffer more ill health than their counterparts in adult care.     

Backscattered electron imaging: the role in calcified tissue and implant analysis

The working distance and tilt studies helped to clarify the influences of specimen variability when the BSE mode is used in calcified tissue research. This work has shown that the BSEPs of cortical bone may be accurately maintained within 2 percent error over a 10 degree range of tilt, or 300 microns working distance variation. If future bone and implant investigators wish to conduct accurate, quantitative mineral microanalysis in bone, then standard grinding and polishing techniques should be adequate if calibration procedures are developed. The BSEP characteristics of the pure metals make them suitable to be used for calibrating the BSE signal. BSE analysis, with correlated biomechanical studies, will lead us to a better understanding of the relationships between structure, function, and mineral content in bone. On-line BSEP analysis techniques will expand our understanding of the mineralization events in bone which are associated with aging, weightlessness, pharmaceutical therapies, and the presence of biomaterials. The future of the BSE imaging technology and the contributions to be made in understanding the histometry, biomechanics and mineral content of bone as well as bone's response to implant materials has just begun to unfold.     

Malignant histiocytosis complicating rheumatoid arthritis: report of four cases.

Four patients with rheumatoid arthritis developed a similar type of lymphoreticular tumour. The morphology and immunocytochemical findings suggested that this was a form of malignant histiocytosis: there may be an important correlation between this tumour and rheumatoid arthritis.