4E). We then investigated the quantitative relationship between fiber diameter and internodal length (Fig. 5). Akt inhibitor following nerve transection, internodal length varied considerably among fibers, as evidenced by the higher scatter of diameter versus internodal length points (Fig. 5A–D), although it was directly related to fiber

diameter in normal nerves (Fig. 5E). The internodal length of most regenerated fibers ranged from 100 to 400 μm, and it tended to increase with increasing fiber diameter at each stage when the fiber diameter was smaller than around 7 μm. However, when the fiber diameter exceeded 7 μm after 100 days, the internodal length tended to decrease with increasing fiber diameter. The correlation between fiber diameter (x2) and internodal Inhibitors,research,lifescience,medical length (y2) was expressed as a linear regression line by the following formula: y2=A2×x2+B2, where x2 is fiber diameter and y2 is internodal length. As shown in Figure 3, the linear regression

lines for the transected nerves at 50, 100, 150, and 200 days Inhibitors,research,lifescience,medical have significantly flatter slopes than those for the control nerves. Furthermore, Inhibitors,research,lifescience,medical the correlation between fiber diameter and internodal length was weaker at every posttransection time point (coefficients ranging from 0.393 to 0.694). In contrast, there was a strong correlation between the fiber diameter (x3) and the ratio of the quotient internodal length to fiber diameter (IL/FD) (y3), with a logarithmic regression curve as follows: y3=E× log(x3) +F. Indeed, although the logarithmic relation in normal nerves

was Inhibitors,research,lifescience,medical weak (r3= 0.384), there were strong logarithmic correlations at each time point during nerve regeneration (coefficients ranging from 0.628 to 0.745). When the regression curves for regenerating fibers Inhibitors,research,lifescience,medical were superimposed, the regression curves at each time point after transection were overlapping, indicating that this fiber diameter to IL/FD relationship is also a poor index of functional recovery. Figure 5 Scatter plots of fiber diameter against internodal length and quotient internodal length/fiber diameter (IL/FD). Fifty days (n= 1146) (A), 100 days (n= 1421) (B), 150 days (n= 1432) (C), and 200 days (n= 1452) (D) after nerve transection. Control values … Discussion New nerve repair techniques should only be introduced into general clinical practice if they can be conclusively Ribonucleotide reductase proved efficient in improving the results obtained from previous techniques. To reach this goal, evaluation methods that provide an objective measure of recovery are required. Animal models also provide objective measures of functional recovery in a manner not presently obtainable in clinical studies. Morphological and electrophysiological measures reflect the inherent variability in the rate of nerve regeneration, myelination, and functional recovery; therefore, a combination of electrophysiological and morphometric measures may yield the best indication of recovery, especially over multiple time points.