A systematic review of the effect of oral antioxidants on male infertility.

The use of antioxidants in treatment of infertile men has been suggested, although the evidence base for this practice is unclear. A systematic review of randomized studies was conducted to evaluate the effects of oral antioxidants (vitamins C and E, zinc, selenium, folate, carnitine and carotenoids) on sperm quality and pregnancy rate in infertile men. MEDLINE, EMBASE, Cochrane Library and CINAHL were searched for relevant trials published from respective database inception dates to May 2009. Study selection, quality appraisal and data extraction were performed independently and in duplicate. Seventeen randomized trials, including a total of 1665 men, were identified, which differed in the populations studied and type, dosage and duration of antioxidants used. Only two-thirds of the studies (11/17) reported using allocation concealment and three studies (18%) used intention-to-treat analysis. Despite the methodological and clinical heterogeneity, 14 of the 17 (82%) trials showed an improvement in either sperm quality or pregnancy rate after antioxidant therapy. Ten trials examined pregnancy rate and six showed a significant improvement after antioxidant therapy. The use of oral antioxidants in infertile men could improve sperm quality and pregnancy rates. Adequately powered robust trials of individual and combinations of antioxidants are needed to guide clinical practice.

Impact of electrical cable insulating oil on the mineralisation of [1-(14)C]glucose in soil.

Subsurface high voltage electric cables are commonly insulated using dodecylbenzene in combination with mineral oil. This work assessed the impact of increasing concentrations of cable insulating oil (0-10% dry weight) on soil microbial respiration as determined by mineralisation of [1-(14)C]glucose (11 microg C g(-1) soil). Acute impact was assessed from 0 days to 21 days, and chronic impact was assessed after 300 days. This study found that cable insulating oil increased respiratory activity of soil microflora. The extent of impact was found to depend on both oil concentration and the length of oil-soil contact time. Following acute exposure (21-days oil-soil contact time), it was found that oil concentrations up to 1% promoted a significant (P<0.05) increase in the extent of [1-(14)C]glucose mineralisation to (14)CO(2) relative to the control. In contrast, higher concentrations of cable insulating oil (5% and 10%) promoted no significant (P0.05) increase in the extent of [1-(14)C]glucose mineralisation to (14)CO(2) relative to the control. Following chronic exposure (300-days oil-soil contact time), the extent of mineralisation was greater at all oil concentrations applied relative to the control. For oil concentrations up to and including 1%, there was a decrease in the extent of elevation in mineralisation relative to the values after 21-days exposure. At higher oil concentrations, namely 5% and 10%, the extent of elevation in mineralisation was comparable with that after 21-days oil-soil contact time. We suggest that the increase in mineralisation of glucose indicates that cable insulating oil is a readily available carbon source to the carbon-limited soil microflora.

A simple (14)C-respirometric method for assessing microbial catabolic potential and contaminant bioavailability.

This paper describes the validation and application of a simple flask-based (14)C-respirometer system designed to assess mineralisation of (14)C-labelled substrates under defined conditions. Validation of this respirometer system indicated stoichiometric CO(2) trapping up to a maximum of 400 micromol of CO(2) (in a single trap). Polycyclic aromatic hydrocarbon (PAH)-degrading bacteria were used to measure growth-linked biodegradation of [(14)C]naphthalene to (14)CO(2). A (14)C activity balance of 101.7+/-8.9% (n=6), after 74 h incubation time and 10 respirometer-opening events, indicated the suitability of the system for monitoring substrate mineralisation. This respirometric apparatus was then successfully applied to assess: (i) the PAH catabolism of microbes in a field contaminated soil, where naphthalene and phenanthrene were rapidly mineralised and (ii) soil-associated organic contaminant bioavailability, where increased soil-phenanthrene contact time resulted in a reduction in phenanthrene mineralisation in the soil. The described respirometer system differs from existing respirometer systems in that the CO(2) trap can be removed and replaced quickly and easily. The system is efficient, reproducible, adaptable to many situations, easy to construct and simple to use, it therefore affords advantages over existing systems.

Development of QSARs to investigate the bacterial toxicity and biotransformation potential of aromatic heterocylic compounds.

A series of aromatic heterocyclic and hydrocarbon compounds were tested for toxicity and biotransformation potential against two contrasting lux-marked whole-cell microbial biosensors. Toxicity was determined by inhibition of light output of a Pseudomonas fluorescens construct that expresses lux constitutively. Biotransformation was tested by increase in light output of P. fluorescens HK44 (pUTK21), which expresses lux when in the presence of a metabolic intermediate (salicylate). The data were then modelled against physical/chemical properties of the compounds tested to see if quantitative structure-activity relationships (QSARs) could be derived. Toxicity was found to be accurately predicted by log Kow (R2 = 0.95, Q2 = 0.88), with the basic (pyridine-ring containing) heterocycles modelled separately. The biotransformation data were best modelled using lowest unoccupied molecular orbital (LUMO) energies (R2 = 0.90, Q2 = 0.87).

Comparison of microvascular filtration characteristics in isolated and intact lungs.

To determine whether the microvascular membrane of isolated perfused dog lungs is damaged by the isolation procedure, we compared the filtration coefficient (Kf,c) and minimum capillary pressure (Pcc) required to cause continuous edema formation in 10 intact and 8 isolated dog lower left lobes. We used the same gravimetric technique to measure Kf,c and Pcc in both preparations. The Kf,c averaged 0.09 +/- 0.03 (SD) ml . min-1 . Torr-1 . 100 g-1 in the intact and 0.30 +/- 0.16 in the isolated lobes; Pcc averaged 20.1 +/- 4.7 and 1.7 +/- 3.6 Torr in the intact and isolated lobes, respectively. Both Pcc and Kf,c were significantly different in the two preparations (P less than 0.01). These data indicate that the increased tendency of isolated lungs to become edematous at lower pressures may be caused by damage to the microvascular membranes.