Skeletal muscle mitochondrial capacity in patients with statin-associated muscle symptoms (SAMS).

Objective: The objective of this article is to evaluate near-infrared spectroscopy (NIRS), a non-invasive technique to assess tissue oxygenation and mitochondrial function, as a diagnostic tool for statin-associated muscle symptoms (SAMS).

Methods: We verified SAMS in 39 statin-treated patients (23 women) using a double-blind, placebo-controlled, cross-over protocol. Subjects with suspected SAMS were randomised to simvastatin 20 mg/day or placebo for 8 weeks, followed by a 4-week no treatment period and then assigned to the alternative treatment, either simvastatin or placebo.

25(OH) vitamin D is associated with greater muscle strength in healthy men and women.

Purpose: The purpose of the study was to examine the relation between serum 25-hydroxy vitamin D (25(OH)D) levels and muscle strength in 419 healthy men and women over a broad age range (20-76 yr).

Methods: Isometric and isokinetic strength of the arms and legs was measured using computerized dynamometry, and its relation to vitamin D was tested in multivariate models controlling for age, gender, resting HR, systolic blood pressure, diastolic blood pressure, body mass index, maximal oxygen uptake (VO(2max)), physical activity counts, and season of vitamin D measurement.

Results: Vitamin D was significantly associated with arm and leg muscle strength when controlling for age and gender.

Threshold dynamics in a time-delayed epidemic model with dispersal.

The global dynamics of a time-delayed model with population dispersal between two patches is investigated. For a general class of birth functions, persistence theory is applied to prove that a disease is persistent when the basic reproduction number is greater than one. It is also shown that the disease will die out if the basic reproduction number is less than one, provided that the initial size of the infected population is relatively small.

A periodic Droop model for two species competition in a chemostat.

Both uniform persistence and the existence of periodic coexistence state are established for a periodically forced Droop model on two phytoplankton species competition in a chemostat under some appropriate conditions. Numerical simulations using biological data are presented as well to illustrate the main result.