Does obesity affect the outcomes of primary total knee arthroplasty?

The purpose of this study was to compare the clinical and radiographic outcomes of primary total knee arthroplasty (TKA) in obese and nonobese patients. A total of 210 knees in 174 obese patients who had a mean body mass index (BMI) of 34 kg/m2 (range, 30 to 39.9 kg/m2) and who had undergone a primary TKA between 2006 and 2010 were reviewed. There were 115 women and 59 men who had a mean age of 62 years (range, 36 to 84 years) and a mean follow-up of 57 months (range, 24 to 82 months). These patients were compared with a group of nonobese patients who had a BMI of less than 30 kg/m2 (range, 19 to 29.9 kg/m2). The evaluated outcomes included implant survivorship, Knee Society objective and functional scores, complication rates, radiographic outcomes, University of California Los Angeles (UCLA) activity score, and the length of hospital stay between obese and nonobese patients. There were no significant differences in the overall septic and aseptic implant survivorship (98.8 vs. 98.6%) and mean postoperative Knee Society objective and function scores (90 and 87 points vs. 91 and 89 points), respectively. Obese patients had significantly higher complication rates (10.5 vs. 3.8%) and had achieved a significantly lower mean postoperative UCLA activity score (5 vs. 6 points). However, there were no differences in the length of hospital stay for the two cohorts. Although the authors encourage all patients to lose weight as much as possible prior to their TKA, it is encouraging that obese patients had achieved excellent clinical outcomes at early to mid-term follow-up.

Selective, direct activation of high-conductance, calcium-activated potassium channels causes smooth muscle relaxation.

High-conductance calcium-activated potassium (Maxi-K) channels are present in smooth muscle where they regulate tone. Activation of Maxi-K channels causes smooth muscle hyperpolarization and shortening of action-potential duration, which would limit calcium entry through voltage-dependent calcium channels leading to relaxation. Although Maxi-K channels appear to indirectly mediate the relaxant effects of a number of agents, activators that bind directly to the channel with appropriate potency and pharmacological properties useful for proof-of-concept studies are not available. Most agents identified to date display significant polypharmacy that severely compromises interpretation of experimental data. In the present study, a high-throughput, functional, cell-based assay for identifying Maxi-K channel agonists was established and used to screen a large sample collection (>1.6 million compounds). On the basis of potency and selectivity, a family of tetrahydroquinolines was further characterized. Medicinal chemistry efforts afforded identification of compound X, from which its two enantiomers, Y and Z, were resolved. In in vitro assays, Z is more potent than Y as a channel activator. The same profile is observed in tissues where the ability of either agent to relax precontracted smooth muscles, via a potassium channel-dependent mechanism, is demonstrated. These data, taken together, suggest that direct activation of Maxi-K channels represents a mechanism to be explored for the potential treatment of a number of diseases associated with smooth muscle hyperexcitability.

Miniaturization and automation of an ubiquitin ligase cascade enzyme-linked immunosorbent assay in 1,536-well format.

Enzyme-linked immunosorbent assays (ELISAs) are a long established and widely used assay format for drug discovery and diagnostics. They offer many advantages over homogeneous assay formats, including high sensitivity and separation (wash) steps that remove detection-interfering compounds. Many high-throughput screening assays are now performed in miniaturized formats (1,536- and 3,456-well plates) for higher throughput and lower reagent consumption. With miniaturization, separation steps in assays such as ELISA can become difficult to implement. Here we report on the implementation of the Kalypsys, Inc. (San Diego, CA) 1,536-well plate washer to enable the successful miniaturization and full automation of an ELISA that monitors ubiquitin ligase activity. The 1,536-well plate ELISA was robust and used for the high-throughput screening of a large screening collection (>1 million compounds).