Spectroscopic investigation of local mechanical impedance of living cells.

We studied nanoscale mechanical properties of PC12 living cells with a Force Feedback Microscope using two experimental approaches. The first one consists in measuring the local mechanical impedance of the cell membrane while simultaneously mapping the cell morphology at constant force. As the interaction force is increased, we observe the appearance of the sub-membrane cytoskeleton.

Axotomy-induced expression of calcium-activated chloride current in subpopulations of mouse dorsal root ganglion neurons.

Whole cell patch-clamp recordings of calcium-activated chloride current [ICl(Ca)] were made from adult sensory neurons of naive and axotomized mouse L4-L6 lumbar dorsal root ganglia after 1 day of culture in vitro. A basal ICl(Ca) was specifically expressed in a subset of naive medium-diameter neurons (30-40 microm). Prior nerve injury, induced by sciatic nerve transection 5 days before experiments, increased both ICl(Ca) amplitude and its expression in medium-diameter neurons.

N19S, a new SOD1 mutation in sporadic amyotrophic lateral sclerosis: no evidence for disease causation.

In a group of 331 sporadic amyotrophic lateral sclerosis (ALS) cases, we identified a new Cu/Zn superoxide dismutase single base substitution, N19S, in two patients. In the first case, seven healthy family members of 15 carried the substitution. Controls (n = 268) and familial ALS index cases (n = 180) were screened and one control subject with N19S was identified.