Vitamin d and rehabilitation: improving functional outcomes.

Vitamin D inadequacy is pandemic among rehabilitation patients in both inpatient and outpatient settings. Male and female patients of all ages and ethnic backgrounds are affected. Vitamin D deficiency causes osteopenia, precipitates and exacerbates osteoporosis, causes the painful bone disease osteomalacia, and worsens proximal muscle strength and postural sway. Vitamin D inadequacy can be prevented by sensible sun exposure and adequate dietary intake with supplementation. Vitamin D status is determined by measurement of serum 25-hydroxyvitamin D. The recommended healthful serum level is between 30 and 60 ng/mL. 25-Hydroxyvitamin D levels of >30 ng/mL are sufficient to suppress parathyroid hormone production and to maximize the efficiency of dietary calcium absorption from the small intestine. This can be accomplished by ingesting 1000 IU of vitamin D(3) per day, or by taking 50,000 IU of vitamin D(2) every 2 weeks. Vitamin D toxicity is observed when 25-hydroxyvitamin D levels exceed 150 ng/mL. Identification and treatment of vitamin D deficiency reduces the risk of vertebral and nonvertebral fractures by improving bone health and musculoskeletal function. Vitamin D deficiency and osteomalacia should be considered in the differential diagnosis of patients with musculoskeletal pain, fibromyalgia, chronic fatigue syndrome, or myositis. There is a need for better education of health professionals and the general public regarding the optimization of vitamin D status in the care of rehabilitation patients.

Polyglutamine homopolymers having 8-45 residues form slablike beta-crystallite assemblies.

At least nine inherited neurodegenerative diseases, including Huntington's, are caused by poly(L-glutamine) (polyGln, polyQ) expansions > 35-40 repeats in widely or ubiquitously expressed proteins. Except for their expansions, these proteins have no sequence homologies, and their functions mostly remain unknown. Although each disease is characterized by a distinct pathology specific to a subset of neuronal cells, the formation of neuronal intranuclear aggregates containing protein with an expanded polyQ is the hallmark and common feature to most polyQ disorders. The neurodegeneration is thought to be caused by a toxic gain of function that occurs at the protein level and depends on the length of the expansion: Longer repeats cause earlier age of onset and more severe symptoms. To address whether there is a structural difference between polyQ having < 40 versus > 40 residues, we undertook an X-ray fiber diffraction study of synthetic polyQ peptides having varying numbers of residues: Ac-Q8-NH2, D2Q15K2, K2Q28K2, and K2Q45K2. These particular lengths bracket both the range of normalcy (9-36 repeats) and the pathological (45 repeats), and therefore could be indicative of the structural changes expected in expanded polyQ domains. Contrary to expectations of different length-dependent morphologies, we accounted for all the X-ray patterns by slablike, beta-sheet structures, approximately 20 A thick in the beta-chain direction, all having similar monoclinic lattices. Moreover, the slab thickness indicates that K2Q45K2, rather than forming a water-filled nanotube, must form multiple reverse turns.

Poly-(L-alanine) expansions form core beta-sheets that nucleate amyloid assembly.

Expansion to a total of 11-17 sequential alanine residues from the normal number of 10 in the polyadenine-binding protein nuclear-1 (PABPN1) results in formation of intranuclear, fibrillar inclusions in skeletal muscle and hypothalamic neurons in adult-onset, dominantly inherited oculopharyngeal muscular dystrophy (OPMD). To understand the role that homopolymeric length may play in the protein misfolding that leads to the inclusions, we analyzed the self-assembly of synthetic poly-(L-alanine) peptides having 3-20 residues. We found that the conformational transition and structure of polyalanine (polyAla) assemblies in solution are not only length-dependent but also are determined by concentration, temperature, and incubation time. No beta-sheet complex was detected for those peptides characterized by n < 8, where n is number of alanine residues. A second group of peptides with 7 < n < 15 showed varying levels of complex formation, while for those peptides having n > 15, the interconversion process from the monomeric to the beta-sheet complex was complete under any of the tested experimental conditions. Unlike the typical tinctorial properties of amyloid fibrils, polyalanine fibrils did not show fluorescence with thioflavin T or apple-green birefringence with Congo red; however, like amyloid, X-ray diffraction showed that the peptide chains in these fibrils were oriented normal to the fibril axis (i.e., in the cross-beta arrangement). Neighboring beta-sheets are quarter-staggered in the hydrogen-bonding direction such that the alanine side-chains were closely packed in the intersheet space. Strong van der Waals contacts between side-chains in this arrangement likely account for the high stability of the macromolecular fibrillar complex in solution over a wide range of temperature (5-85 degrees C), and pH (2-10.5), and its resistance to denaturant (< 8 M urea) and to proteases (protease K, trypsin). We postulate that a similar stabilization of an expanded polyalanine stretch could form a core beta-sheet structure that mediates the intermolecular association of mutant proteins into fibrillar inclusions in human pathologies.

Demographics and attitudes of chronic-pain patients who seek online pain-related medical information: implications for healthcare providers.

OBJECTIVE: To identify the demographics, search characteristics, and attitudes of chronic-pain patients who access online pain-related medical information. DESIGN: This is a cross-sectional survey study. RESULTS: Ninety percent of patients had access to the Internet; 63% of patients used the Internet to obtain online pain-related medical information, of which 57% and 55% believed that the information was "useful" and "credible," respectively. Ninety-five percent of current online pain-related medical information users and 52% of nonusers planned to use the Internet in the future to obtain online pain-related medical information. Only half of our subjects ever shared the information found on Internet with their treating healthcare provider. CONCLUSIONS: A large proportion of chronic-pain patients use the Internet to obtain online pain-related medical information. This behavior was found to show significant correlation with patients' level of education. Despite multiple previous studies suggesting inaccurate and low quality of online medical information, most of the patients felt confident in the credibility of online pain-related medical information obtained. Furthermore, many patients choose not to share this information with their healthcare providers. Healthcare providers must acknowledge the growing importance of Internet-based health information, be prepared to entertain questions and assist patients in evaluating the quality of online pain-related medical information, and possibly proactively suggest quality third-party pain-related websites.

Vitamin D deficiency and osteoporosis in rehabilitation inpatients.

OBJECTIVE: To determine vitamin D status and bone mineral density (BMD) in patients admitted to a subacute rehabilitation facility. DESIGN: Cross-sectional cohort study. SETTING: Subacute rehabilitation facility. PARTICIPANTS: Fifty-three community-dwelling patients admitted from June through February 2005. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: BMD, 25-hydroxyvitamin D (25[OH]D), C-telopeptide (CTX), osteocalcin, and dietary milk intake. RESULTS: Prevalence of vitamin D deficiency (25[OH]D <20 ng/mL) was 49.1%, while a total of 83% of patients were either vitamin D deficient or insufficient (25[OH]D <30 ng/mL). The prevalence of osteopenia (T score, <-1) was 52.8%; osteoporosis (T score, <-2.5) was 17.0%. CTX (bone resorption marker) was elevated in 60.4% of patients. Osteocalcin (bone formation marker) was elevated in 13.2% of patients. Measurements of bone resorption and formation positively correlated (R2 = .22) indicating increased bone remodeling. CONCLUSIONS: Vitamin D deficiency and osteopenia and osteoporosis were highly prevalent in patients admitted for rehabilitation. Elevated bone resorption and remodeling were evident. This could be due to vitamin D deficiency that should be corrected before antiresorptive therapy is considered. The study emphasizes the need for vigilance for vitamin D status and BMD testing in patients admitted to rehabilitation facilities.