Changes in collagen type for RF-induced rat sciatic nerve injury.

<p>(A) CO, SH and PRF groups showed the normal collagen ultrastructure encasing NFs, while the CRF group showed loss or destruction of collagen structure. CO, control; SH, sham; PRF, pulsed RF; CRF, continuous RF. CF, collagen fiber = epi-perineurial layer; NF, nerve fiber = endoneurial layer. Scale bar = 200 µm. The intensities of immunoreactivity for (B) collagen type I and (C) collagen type III in the epi-perineurium and endoneurium of rat sciatic nerves on day 7 after the RF treatment were decreased in comparison with those in the CO and SH groups. Scale bar = 200 µm. (D) The PRF group showed significant decreases in the protein expression of both endoneurial collagen types I and III (P<0.005). The CRF group showed significant decreases in the protein expression of epi-perineurial collagen type I (P<0.0001) and endoneurial collagen type III (P<0.0001). Data shown are the mean and SD of six mice (n = 18). COL1, collagen type I; COL3, collagen type III. **P<0.005, ***P<0.0001 vs. CO.</p

Morphological changes in NFs for RF-induced rat sciatic nerve injury.

<p>NF, nerve fiber. RF, radiofrequency. (A) The CO and SH groups exhibited normal ovoid-shaped NFs, while the PRF group exhibited some myelinated axon damage and swelling of the myelinated axons, and the CRF group had severely degenerated and stunted myelinated axons or swelling and absence of mitochondria. CO, control; SH, sham; PRF, pulsed RF; CRF, continuous RF. Scale bar = 50 µm. (B) Definition of NFs for counting. M, myelin; A, axon. Scale bar = 5 µm. (C) Each group showed significantly different numbers of total, normal and degenerated NFs (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073913#pone-0073913-t001" target="_blank">Table 1</a>). Both RF groups showed half of the total numbers of NFs in the CO group. (D) RF led to a significant decrease in normal NFs compared to the CO group. (E) CRF led to a significant increase in degenerated NFs compared to the CO group. These analyses were performed within an area of 250×250 µm². Data shown are the mean and SD of six mice (n = 18). ***P<0.0001 vs. CO.</p

Quantitative changes in total CFs for RF-induced rat sciatic nerve injury.

<p>CF, collagen fiber. RF, radiofrequency. (A) CO and SH groups showed normal collagen structure encasing NFs while the RF groups showed significant decreases in total collagen density. CO, control; SH, sham; PRF, pulsed RF; CRF, continuous RF. CF = epi-perineurial layer; NF, nerve fiber = endoneurial layer. Scale bar = 250 µm. (B) Ratios of total collagen for each treatment group normalized against the CO group. COL, collagen. Data shown are the mean and SD of six mice (n = 18). *P<0.05; ***P<0.0001 vs. CO.</p

Up-regulation of TNF-α and IL-6 for RF-induced peripheral nerve injury.

<p>RF, radiofrequency. The expression of TNF-α and IL-6 proteins in rat sciatic nerves with no treatment (CO), no current (SH), PRF and CRF was visualized by immunohistochemistry before stimulation (Pre) and on days 0, 2, 7 and 30 after stimulation. (A) Representative immunohistochemistry images on day 7 after RF treatment are shown. CO, control; SH, sham; PRF, pulsed RF; CRF, continuous RF. Scale bar = 100 µm. (B) The SH group showed no significant changes in TNF-α expression over the 30-day experimental period as compared to the CO group. In contrast, TNF-α expression was up-regulated immediately after RF treatment. This up-regulation persisted until days 7 and 30 after the PRF and CRF treatments, respectively. (C) Changes in IL-6 expression were similar to those observed for TNF-α. Scale bar = 100 µm. (D) IL-6 immunoreactivity reached a maximum on day 7 after exposure to PRF (P<0.005) and CRF (P<0.0001). Data shown are the mean and SD of six mice (n = 18). *P<0.05, **P<0.005, ***P<0.0001 vs. CO.</p

Morphological changes in the epineurial CFs for RF-induced rat sciatic nerve injury.

<p>CF, collagen fiber. RF, radiofrequency. (A) Nanostructural alternation of RF-induced CFs was evaluated by AFM throughout a postoperative period of 30 days using an NANOS N8 NEOS with a scan size of 2500 × 5000 nm² and a scan speed of 0.8 lines/s at 35% relative humidity and room temperature. AFM, atomic force microscopy. CO, control; SH, sham; PRF, pulsed RF; CRF, continuous RF. ★, suspected CFs. Scale bar = 500 nm. (B) The mean diameters of the epineurial CFs for the CO and SH groups were 93.78±23.09 nm and 94.98±43.07 nm, respectively. PRF led to a significant swelling of the epineurial CFs (186.55±22.74 nm). There were no collagen composites in the CRF group, but there were some suspected CF composites (★ mark, 191.27±19.50 nm). (C) Three-dimensional AFM images were reconstructed from AFM tapping-mode topographical images by SPIP software. These images show the clear axial periodicity of the CFs. Scale bar = 500 nm. Data shown are the mean and SD of three mice (n = 9). **P<0.005 vs. CO.</p

Morphological changes in nerve fibers for RF-induced rat sciatic nerve injury (n = 18). This calculation was performed within an area of 250×250 µm².

*<p>P<0.05,</p>***<p>P<0.0001 vs. CO.</p

Correlation of optic nerve sheath diameter with directly measured intracranial pressure in Korean adults using bedside ultrasonography

<div><p>Objectives</p><p>The correlation of optic nerve sheath diameter (ONSD) as seen on ultrasonography (US) and directly measured intracranial pressure (ICP) has been well described. Nevertheless, differences in ethnicity and type of ICP monitor used are obstacles to the interpretation. Therefore, we investigated the direct correlation between ONSD and ventricular ICP and defined an optimal cut-off point for identifying increased ICP (IICP) in Korean adults with brain lesions.</p><p>Methods</p><p>This prospective study included patients who required an external ventricular drainage (EVD) catheter for ICP control. IICP was defined as an opening pressure over 20 mmHg. ONSD was measured using a 13 MHz US probe before the procedure. Linear regression analysis and receiver operator characteristic (ROC) curve were used to assess the association between ONSD and ICP. Optimal cut-off value for identifying IICP was defined.</p><p>Results</p><p>A total of 62 patients who underwent ONSD measurement with simultaneous EVD catheter placement were enrolled in this study. Thirty-two patients (51.6%) were found to have IICP. ONSD in patients with IICP (5.80 ± 0.45 mm) was significantly higher than in those without IICP (5.30 ± 0.61 mm) (<i>P</i> < 0.01). The IICP group showed more significant linear correlation with ONSD (r = 0.57, <i>P</i> < 0.01) compared to the non-IICP group (r = 0.42, <i>P</i> = 0.02). ONSD > 5.6 mm disclosed a sensitivity of 93.75% and a specificity of 86.67% for identifying IICP.</p><p>Conclusion</p><p>ONSD as seen on bedside US correlated well with directly measured ICP in Korean adults with brain lesions. The optimal cut-off point of ONSD for detecting IICP was 5.6 mm.</p></div

Baseline characteristics of patients used in this study (n = 62).

<p>Baseline characteristics of patients used in this study (n = 62).</p

Scatterplot relating optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) according to the presence of increased intracranial pressure (IICP).

<p>The linear prediction from regression is shown as solid or dotted line.</p