The effectiveness of exercise for the prevention and treatment of antenatal depression: systematic review with meta-analysis.

BACKGROUND: Antenatal depression can have harmful consequences for the mother and fetus. Exercise may be a useful intervention to prevent and treat antenatal depression. OBJECTIVES: This systematic review aims to establish whether there is sufficient evidence to conclude that exercise is an effective intervention for preventing and treating antenatal depression. SEARCH STRATEGY: Searches using electronic databases from MEDLINE, Cochrane Library, CINAHL, EMBASE, AMED and PsycINFO were performed. SELECTION CRITERIA: Randomised controlled trials (RCT) that compared any type of exercise intervention with any comparator in pregnant women were eligible for inclusion. DATA COLLECTION AND ANALYSIS: Meta-analysis was performed calculating standardised mean differences (SMD). MAIN RESULTS: Six trials (seven comparisons) were eligible for inclusion. Meta-analysis showed a significant reduction in depression scores (SMD -0.46, 95% CI -0.87 to -0.05, P = 0.03, I(2) = 68%) for exercise interventions relative to comparator groups. The test for subgroup differences in women who were non-depressed (one trial) (SMD -0.74, 95%CI -1.22 to -0.27, P = 0.002) and depressed (five trials) (SMD -0.41, 95% CI -0.88 to 0.07, P = 0.09) at baseline was not significant (P = 0.32). The test for subgroup differences between aerobic (one trial) and non-aerobic exercise (five trials) was also nonsignificant (P = 0.32). AUTHORS' CONCLUSIONS: We found some evidence that exercise may be effective in treating depression during pregnancy but this conclusion is based on a small number of low-moderate quality trials with significant heterogeneity and wide confidence intervals.

The penetration of antibiotics into aggregates of mucoid and non-mucoid Pseudomonas aeruginosa.

Cells of mucoid and non-mucoid Pseudomonas aeruginosa in colonies were at least one-thousandfold less sensitive to the antibiotics tobramycin or cefsulodin than were cells of the same bacteria in dispersed suspension. We did not detect any difference between the mucoid form and the non-mucoid form in the antibiotic sensitivity of colonies, from which we infer that the exopolysaccharide of the mucoid form does not contribute to colony-resistance by forming a barrier to antibiotic diffusion. Mathematical models were constructed in order to estimate time-courses of penetration of tobramycin and cefsulodin into biofilms and microcolonies of mucoid and non-mucoid P. aeruginosa. For tobramycin penetration, adsorption of antibiotic to the exopolysaccharide of the glycocalyx and antibiotic uptake by cells were taken into account in the calculations. The longest time-period for the concentration of tobramycin at the base of a biofilm 100 micron deep to rise to 90% of the concentration outside the biofilm was predicted to be 2.4 h. For cefsulodin penetration, irreversible hydrolysis catalysed by beta-lactamase was taken into account, using beta-lactamase levels taken from the literature. The calculations predicted that the cefsulodin concentration at the base of a biofilm 100 micron deep would rise to 90% of the external concentration in 29 s when the beta-lactamase was synthesized at the basal level. For a similar biofilm of bacteria synthesizing enhanced levels of beta-lactamase ('derepressed'), the concentration of cefsulodin at the base was calculated to rise to 41% of the external concentration in about 50 s and then remain at that level. This was despite the fact that cefsulodin is a poor substrate for this beta-lactamase.

Inhibition of tobramycin diffusion by binding to alginate.

[3H]tobramycin bound to sodium alginate and to exopolysaccharide prepared from two mucoid strains of Pseudomonas aeruginosa. Binding to sodium alginate was similar to binding to exopolysaccharide, both in the dependence on tobramycin concentration and in the maximum binding observed at saturation. Incorporation of sodium alginate into agar plates reduced the zone sizes of growth inhibition caused by tobramycin. The reductions in zone sizes were quantitatively accounted for by the binding of tobramycin to sodium alginate during diffusion of the antibiotic away from the well in which it had been placed at the start of the experiment. However, the binding of tobramycin to the exopolysaccharide of P. aeruginosa, and the resulting inhibition of diffusion of the antibiotic, did not significantly increase the penetration time of a spherical microcolony with a radius of 125 micron, such as might be found in the respiratory tract of a patient with cystic fibrosis (from a 90% penetration time of 12 s in the absence of exopolysaccharide to one of 35 s with an exopolysaccharide concentration of 1.0% [wt/vol]).