Breeding the hyperaccumulator Noccaea caerulescens for trace metal phytoextraction: first results of a pure-line selection.

To initiate the creation of phytoextraction cultivars, plants were selected from 60 populations of N. caerulescens for their high shoot biomass or Cd, Ni, and Zn concentrations. They were self-pollinated, and the selection and fixation were continued for three generations in greenhouse conditions. Selected plants showed a potential to produce 5-10 t dry matter ha-1, which is required to decontaminate soils which have been moderately contaminated with Cd. However, the high biomass genotypes could not be fixed, probably both because of their complexity and to the sensitivity of this trait to environmental conditions, and plant density in particular. The selection led to an improvement to the Cd and Zn accumulation capacities of the plants, yet caused a decrease in their Ni accumulation. This is most likely due to a decline in Ni availability in soil, rather than to a deleterious effect of inbreeding. Metal accumulation appeared to be more heritable than biomass production and fixation for the former trait should be quicker than for the latter. The accumulation capacities of the selected plants permitted offtakes representing around 25% of the soil Cd in a single cropping. This potential has to be confirmed in field conditions.

Computed tomography images of entrapped epidural catheter.

OBJECTIVE: Knotting and looping of catheters in the epidural space occur rarely. Visualization of a catheter by radiograph or fluoroscopy is not always possible and often inaccurate in locating the knot and/or the loop with precision. We report the case of an entrapped lumbar epidural catheter. Computed tomography (CT) clearly showed a knotted and looped catheter. CASE REPORT: A 27-year-old woman underwent epidural analgesia during labor. The epidural catheter was inserted 7 cm into the epidural space. After unsuccessful attempts at removing the catheter, a CT scan was performed, and it showed a catheter knot in the epidural space as well as a loop within the interlaminar ligamentum flavum between L3 and L4. This explained why attempts to remove the catheter by manual traction failed. Surgical removal of the catheter was subsequently performed. CONCLUSIONS: CT is useful in showing an entrapped epidural catheter and the mechanisms of entrapment. Surgery should be considered when gentle traction fails to retrieve the catheter. CT allows the clinician to localize the catheter with accuracy, thus facilitating surgical follow-up.