Objective We sought to estimate the impact of knee osteoarthritis (OA) on health care utilization. Research Design Using the 2003 Medicare Current Beneficiary Survey, a population-based survey of Medicare beneficiaries linked to Medicare claims, we selected a national cohort of community-dwelling persons aged 65 and older with knee OA and a sex- and age-matched comparison cohort without any form of OA. We distinguished following 4 components of health care utilization: physician (MD) office visits, non-MD office visits, inpatient hospital stays, and emergency department visits. We built multiple regression models to determine whether knee OA affects utilization, controlling for comorbidity count, obesity, functional limitation, education, race, and working status. Results A total of 545 Medicare Current Beneficiary Survey participants with knee OA were matched with 1090 OA-free individuals. Mean age in both cohorts was 76 years; approximately 70% were female. Knee OA and OA-free subjects differed significantly in obesity (Knee OA: 37%, OA-free: 20%), % with ≥2 comorbidities (Knee OA: 69%, OA-free: 43%), and functional limitation (Knee OA: 42%, OA-free: 26%). In multivariable regression models, the knee OA cohort had on average 6.0 more annual MD visits (95% confidence interval [CI]: 4.7, 7.4) and 3.8 more non-MD visits (95% CI: 2.8, 4.7) than the OA-free cohort. The knee OA cohort also had 28% more hospital stays (odds ratio [OR] = 1.3, 95% CI: 1.0, 1.6), a difference attributable to total joint replacements. Conclusions This first national, population-based study of health care utilization in persons with knee OA documents considerable excess utilization attributable to knee OA, independent of comorbidity, and other patient characteristics.

MSH2 is required for DNA mismatch repair recognition in eukaryotes. Deleterious mutations in human MSH2 account for approximately half of the alleles associated with a common hereditary cancer syndrome. Previously, we characterized clinically identified MSH2 missense mutations, using yeast as a model system, and found that the most common cause of defective DNA mismatch repair was low levels of the variant Msh2 proteins. Here, we show that increased protein turnover is responsible for the reduced cellular levels. Increasing gene dosage of more than half of the missense alleles fully restored function. A titration experiment revealed that raising the expression level of one variant to less than wildtype levels restored mismatch repair, suggesting that overexpression is not always required to regain function. We found that the ubiquitin-mediated proteasome degradation pathway is the major mechanism for increased turnover of the Msh2 variants and identified the primary ubiquitin ligase as San1. Deletion of San1 restored protein levels for all but one variant, but did not elevate wild-type Msh2 levels. The unstable variants interacted with San1, whereas wild-type Msh2 did not. Additionally, san1Δ suppressed the mismatch repair defect of unstable variants. Of medical significance, the clinically approved drug Bortezomib partially restored protein levels and mismatch repair function for low-level variants and reversed the resistance to cisplatin, a common chemotherapeutic. Our results provide the foundation for an innovative therapeutic regime for certain mismatch-repair-defective cancers that are refractory to conventional chemotherapies.Lynch syndrome | MutS | mutator | hereditary nonpolyposis clorectal cancer L ynch syndrome, also known as hereditary nonpolyposis colorectal cancer, is a leading cause of inherited cancer mortality in the United States (1). Approximately 2-7% of colorectal cancer cases are the consequence of Lynch syndrome, a dominant and highly penetrant disease afflicting individuals at an early age (1). Although colorectal is the most common form of cancer found in Lynch syndrome families, endometrial, ovarian, stomach, small intestine, liver, gallbladder ducts, upper urinary tract, brain, skin, and prostate cancers are all associated with the syndrome.Lynch syndrome cancers, as well as many sporadic tumors, are a consequence of defects in mismatch repair; for example, ∼17% of all colorectal cancers originate from defects in mismatch repair (2). DNA mismatch repair is a conserved mechanism that significantly contributes to the accurate preservation of genetic material (3). Mismatch recognition is accomplished in eukaryotes by MutS heterodimers in which Msh2 is the invariant partner (4). Mismatch binding initiates subsequent events, including cleavage and excision of the error-containing strand followed by new synthesis and ligation (5). Without mismatch repair, DNA displays microsatellite instability and acquires numerous mutations, some of which are deleterious. Included among the types of harmfu...

Purpose A CTEP-sponsored phase II trial was performed to evaluate safety and clinical activity of combination therapy with CCI-779 (temsirolimus) and bevacizumab in patients with advanced melanoma. Experimental Design Patients with unresectable stage III to IV melanoma were treated intravenously with temsirolimus 25mg weekly and bevacizumab 10mg every 2 weeks. Adverse events were recorded using CTCAE v3.0. Tumor response was assessed by Response Evaluation Criteria in Solid Tumors, and overall survival was recorded. Correlative studies measured protein kinases and histology of tumor biopsies, and immune function in peripheral blood. Results Seventeen patients were treated. Most patients tolerated treatment well, but two had grade 4 lymphopenia and one developed reversible grade 2 leukoencephalopathy. Best clinical response was partial response (PR) in three patients (17.7%, 90%CI 5,0–39.6), stable disease at 8 weeks (SD) in 9 patients, progressive disease (PD) in 4 patients, and not evaluable in 1 patient. Maximal response duration for PR was 35 months. Ten evaluable patients had BRAFWT tumors, among whom 3 had PRs, 5 had SD, and 2 had PD. Correlative studies of tumor biopsies revealed decreased phospho-S6K (d2 and d23 vs d1, p<0.001), and decreased mitotic rate (Ki67+) among melanoma cells by d23 (p=0.007). Effects on immune functions were mixed, with decreased alloreactive T cell responses and decreased circulating CD4+FoxP3+ cells. Conclusion These data provide preliminary evidence for clinical activity of combination therapy with temsirolimus and bevacizumab, which may be greater in patients with BRAFwt melanoma. Mixed effects on immunologic function also support combination with immune therapies.