Methylsulfonylmethane for treatment of low back pain: A safety analysis of a randomized, controlled trial.

OBJECTIVE: To ensure that 16 weeks of methylsulfonylmethane (MSM) does not cause adverse effects in patients with the musculoskeletal disorders of osteoarthritis and back pain. DESIGN: We carried out a subgroup analysis on data from a randomized, double-blind, placebo-controlled trial, "The use of Methylsulfonylmethane (MSM) in the treatment of low back pain," to determine the safety of taking 6 g daily of MSM (OptiMSM®, Bergstrom Nutrition). We monitored metabolic parameters to determine whether MSM altered hematologic, liver or kidney function. We also monitored physiologic parameters of blood pressure and weight. SETTING: Family Medicine Residency, Mike O'Callaghan Military Medical Center. MAIN OUTCOME MEASURES: Metabolic parameters as measured by hematologic function - white blood cells (WBC), platelets, hemoglobin (Hb), glucose; liver function as measured by - total bilirubin, alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Physiologic parameters as measured by weight, diastolic (DBP) and systolic blood pressure (SBP); kidney function as measured by creatinine. RESULTS: Analysis of outcome measures showed no significant difference between MSM and placebo (p < 0.05) safety values. CONCLUSION: MSM has no effects on WBC, platelets, Hb, total bilirubin, AST, ALT, creatinine weight, DBP, or SBP in this study.

Gramicidin channels are internally gated.

Gramicidin channels are archetypal molecular subjects for solid-state NMR studies and investigations of single-channel or cation conductance. Until now, the transitions between on and off conductance states have been thought, based on multichannel studies, to represent monomer <--> dimer reactions. Here we use a single-molecule deposition method (vesicle fusion to a planar bilayer) to show that gramicidin dimer channels do not normally dissociate when conductance terminates. Furthermore, the observation of two 13C peaks in solid-state NMR indicates very stable dichotomous conformations for both the first and second peptide bonds in the monomers, and a two-dimensional chemical exchange spectrum with a 12-s mixing time demonstrates that the Val1 carbonyl conformations exchange slowly, with lifetimes of several seconds. It is proposed that gramicidin channels are gated by small conformational changes in the channel near the permeation pathway. These studies demonstrate how regulation of conformations governing closed <--> open transitions may be achieved and studied at the molecular level.