Bone architecture and fracture

Bones are designed to carry out their requirements effectively. One of these requirements is to resist fracture. Two other important requirements are to be stiff and to be light. Few theories of adaptive modeling distinguish modeling for adequate stiffness from modeling for adequate strength. Bones achieve their architecture partially through genetics, the rough form of the bone being laid down in the genes, and partially through response to normal loading. Normal loading rarely includes traumatic loading and bones are not usually well adapted to resist trauma, though they are probably well adapted to fatigue loading. Some aspects of architectural function, such as hollowness, are well understood. Some aspects, such as the need for uniform loading in impact, are less understood, and some, such as size effects, are only now beginning to be investigated.     

Mutations in a conserved enteroviral RNA oligonucleotide sequence affect positive strand viral RNA synthesis

Summary.  We showed earlier that a transition mutation U234C, located within the completely conserved 5 nucleotide (nt) tract 5′-CGUUA (nt232–236) in the 5′ non-translated region (NTR) of the coxsackievirus B3 (CVB3) genome, attenuated CVB3 cardiovirulence in mice. To further explore the role of the sequence, we induced two single and one double transversion mutations in the conserved 5mer in a cardiovirulent CVB3 genome. The mutated sites partially or totally reverted to parental wild-type when progeny viruses were passaged at 37 °C, but remained stable when transfection and subsequent passages were performed at 33.5 °C. Viral replication in cell culture was attenuated at 37 °C or 39.5 °C relative to replication at 33.5 °C. While Western blot analysis demonstrated the level of protein translation consistent with virus replication, the ratios of positive to negative strand viral RNA at 37 °C in murine cells demonstrated a 2–5 fold diminution from those measured at 33.5 °C. Mutant CVB3 strains failed to replicate productively when inoculated into mice. The biological data are consistent with an hypothesis that proposes a lesion with primary effects at the level of positive strand viral RNA synthesis that results in attenuation of viral replication at physiologic temperature. Received December 30, 1999 Accepted May 4, 2000     

Behavioral Aspects of Arthritis and Rheumatic Disease Self-Management

Chronic diseases such as arthritis and related conditions have no ‘cure’, and thus require ongoing management. The long term nature of chronic disease gives the individual a crucial role, if not the most crucial role, in managing their condition. Day-to-day self-management is extremely important in achieving optimal health outcomes, and indeed, people with arthritis use a variety of strategies to relieve symptoms or manage disease consequences.This review identifies and discusses 6 different domains of arthritis self-management behaviors: (i) medical management; (ii) joint protection strategies; (iii) physical activity and exercise; (iv) topical applications; (v) complementary and alternative strategies; and (vi) stress and mind/body practices. Conceptualizing arthritis self-management in this manner enables a discussion of a range of practices that may be used to manage arthritis conditions.The literature on several established arthritis self-management programs that are designed to improve either self-care and/or exercise behaviors is also reviewed. Despite evidence of cost containment and improved health outcomes, these programs reach only a small percentage of people with arthritis who may benefit from them.Clinical intervention for people with arthritis may be enhanced if self-management is approached from a broad perspective and, if established, self-management programs are integrated into clinical interventions.