Boston University

About: Boston University is a education organization based out in Boston, Massachusetts, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 48688 authors who have published 119622 publications receiving 6276020 citations. The organization is also known as: BU & Boston U.

Measuring health status in arthritis ; the arthritis impact measurement scales.

Abstract: A multidimensional index that measures the health status of individuals with arthritis has been developed. The Arthritis Impact Measurement Scales (AIMS) are a combination of previously studied and newly created health status scales which assess physical, emotional, and social well-being. The self-administered AIMS questionnaire has been pilot tested in a mixed arthritis population. Results indicate that the instrument is practical and that it generates scalable, reliable, and valid measures of both aggregated and disaggregated health status. The AIMS approach to health status measurement should prove useful for evaluating the outcomes of arthritis treatments and programs.

Electronic properties of disordered two-dimensional carbon

Abstract: Two-dimensional carbon, or graphene, is a semimetal that presents unusual low-energy electronic excitations described in terms of Dirac fermions. We analyze in a self-consistent way the effects of localized (impurities or vacancies) and extended (edges or grain boundaries) defects on the electronic and transport properties of graphene. On the one hand, point defects induce a finite elastic lifetime at low energies with the enhancement of the electronic density of states close to the Fermi level. Localized disorder leads to a universal, disorder independent, electrical conductivity at low temperatures, of the order of the quantum of conductance. The static conductivity increases with temperature and shows oscillations in the presence of a magnetic field. The graphene magnetic susceptibility is temperature dependent (unlike an ordinary metal) and also increases with the amount of defects. Optical transport properties are also calculated in detail. On the other hand, extended defects induce localized states near the Fermi level. In the absence of electron-hole symmetry, these states lead to a transfer of charge between the defects and the bulk, the phenomenon we call self-doping. The role of electron-electron interactions in controlling self-doping is also analyzed. We also discuss the integer and fractional quantum Hall effect in graphene, the role played by the edge states induced by a magnetic field, and their relation to the almost field independent surface states induced at boundaries. The possibility of magnetism in graphene, in the presence of short-range electron-electron interactions and disorder is also analyzed.

The cell and molecular biology of fracture healing

Abstract: Fracture healing is a complex physiologic process that involves the coordinated participation of several cell types. By using a reproducible model of experimental fracture healing in the rat, it is possible to elucidate the integrated cellular responses that signal the pathways and the role of the extracellular matrix components in orchestrating the events of fracture healing. Histologic characterization of fracture healing shows that intramembranous ossification occurs under the periosteum within a few days after an injury. Events of endochondral ossification occur adjacent to the fracture site and span a period of up to 28 days. Remodeling of the woven bone formed by intramembranous and endochondral ossification proceeds for several weeks. Spatial and temporal expression of genes for major collagens (Types I and II), minor fibrillar collagens (Types IV and XI), and several extracellular matrix components (osteocalcin, osteonectin, osteopontin, fibronectin and CD44) are detected by in situ hybridization. Immunohistochemical studies show that expression of proliferating cell nuclear antigen is both time and space dependent and differentially expressed in the callus tissues formed by the intramembranous and endochondral processes. Chondrocytes involved in endochondral ossification undergo apoptosis (programmed cell death), and early events in fracture healing may be initiated by the expression of early response genes such as c-fos. Additional characterization and elucidation of fracture healing will lay the foundation for subsequent studies aimed at identifying mechanisms for enhancing skeletal repair.

Tamoxifen for the Prevention of Breast Cancer: Current Status of the National Surgical Adjuvant Breast and Bowel Project P-1 Study

Abstract: Background: Initial fi ndings from the National Surgical Adjuvant Breast and Bowel Project Breast Cancer Prevention Trial (P-1) demonstrated that tamoxifen reduced the risk of estrogen receptor – positive tumors and osteoporotic fractures in women at increased risk for breast cancer. Side effects of varying clinical signifi cance were observed. The trial was unblinded because of the positive results, and follow-up continued. This report updates our initial fi ndings. Methods: Women (n = 13 388) were randomly assigned to receive placebo or tamoxifen for 5 years. Rates of breast cancer and other events were compared by the use of risk ratios (RRs) and 95% confi dence intervals (CIs). Estimates of the net benefi t from 5 years of tamoxifen therapy were compared by age, race, and categories of predicted breast cancer risk. Statistical tests were two-sided. Results: After 7 years of follow-up, the cumulative rate of invasive breast cancer was reduced from 42.5 per 1000 women in the placebo group to 24.8 per 1000 women in the tamoxifen group (RR = 0.57, 95% CI = 0.46 to 0.70) and the cumulative rate of noninvasive breast cancer was reduced from 15.8 per 1000 women in the placebo group to 10.2 per 1000 women in the tamoxifen group (RR = 0.63, 95% CI = 0.45 to 0.89). These reductions were similar to those seen in the initial report. Tamoxifen led to a 32% reduction in osteoporotic fractures (RR = 0.68, 95% CI = 0.51 to 0.92). Relative risks of stroke, deep-vein thrombosis, and cataracts (which increased with tamoxifen) and of ischemic heart disease and death (which were not changed with tamoxifen) were also similar to those initially reported. Risks of pulmonary embolism were approximately 11% lower than in the original report, and risks of endometrial cancer were about 29% higher, but these differences were not statistically signifi cant. The net benefi t achieved with tamoxifen varied according to age, race, and level of breast cancer risk. Conclusions: Despite the potential bias caused by the unblinding of the P-1 trial, the magnitudes of all benefi cial and undesirable treatment effects of tamoxifen were similar to those initially reported, with notable reductions in breast cancer and increased risks of thromboem bolic events and endometrial cancer. Readily identifi able sub sets of individuals comprising 2.5 million women could derive a net benefi t from the drug. [J Natl Cancer Inst 2005;97:1652 – 62]