Integrated use of virtual bronchoscopy and endobronchial ultrasonography on the diagnosis of peripheral lung lesions.

Endobronchial ultrasound (EBUS) improves bronchoscopic diagnosis of peripheral lung lesions (PLLs). The procedure time is lengthened by the search through multiple bronchial branches to PLLs. Virtual bronchoscopy (VB) provides endobronchial views that simulate findings at bronchoscopy. An open source software can be employed to study VB and hence the endobronchial route to a PLL. It allows VB to be studied in a Macintosh platform such as a laptop computer. Our purpose was to test if VB generated by this software could shorten procedure time of EBUS-guided bronchoscopy as compared with no VB assistance. The most feasible route to a PLL was manually selected using this software to study VB (VB group). For non-VB group, 2D CT axial +/- coronal images were reviewed to plan bronchoscopy. Before bronchoscopic biopsies, the location of PLL was confirmed by EBUS. Thirty-three subjects were recruited including 16 in VB group and 17 in non-VB group. The mean EBUS examination time and mean total procedure time were reduced in the VB group compared with non-VB group: 5.3 versus 10.5 minutes (P=0.04) and 22.4 versus 29.9 minutes (P=0.044), respectively. There was no complication in the VB group. Although the diagnostic yield was higher in the VB group than non-VB group, our study was not powered to test the difference. This pilot study suggests that VB assistance is safe and shortens procedural time of EBUS-guided bronchoscopy for PLL. Further study is warranted to confirm these findings.

Assessment of intracochlear trauma caused by the insertion of a new straight research array.

OBJECTIVE: To assess the degree of intracochlear trauma using the Cochlear™ Straight Research Array (SRA). This electrode has recently been released by Cochlear™ on the CI422 implant. BACKGROUND: Electroacoustic stimulation (EAS) enables recipients to benefit from cochlear implantation while retaining their natural low-frequency hearing. A disadvantage of short EAS electrodes is that short electrodes provide limited low-frequency stimulation. Thus, loss of the residual hearing may require reimplantation with a longer electrode. In order to overcome this problem, the slim diameter SRA with increased length (20-25 mm) has been designed to provide a deeper, yet non-traumatic insertion. METHODS: Two insertion studies into temporal bones were undertaken. The first involved dissection of the cochlea to gain a view into the scala vestibuli and insertion of the SRA and control electrodes with a microactuator for a surgeon-independent yet controlled insertion. High-speed photography was used to record data. The second study involved a high-resolution X-ray microcomputed tomography (microCT) study to assess electrode placement and tissue preservation in surgeon-implanted bones. RESULTS: The SRA had a smooth insertion trajectory. The average angular insertion depth was 383° when inserted until resistance was encountered, and 355° if inserted to a predetermined mark for EAS use. In addition, microCT data showed that this caused no significant trauma or distortion of the basilar membrane up to 20 mms depth. CONCLUSION: Temporal bone studies show that the SRA appears to cause no intracochlear trauma if used as an EAS electrode up to 20 mm depth of insertion.

Ginsenoside-Rg1 mediates a hypoxia-independent upregulation of hypoxia-inducible factor-1α to promote angiogenesis.

Hypoxia-inducible factor (HIF-1) is the key transcription regulator for multiple angiogenic factors and is an appealing target. Ginsenoside-Rg1, a nontoxic saponin isolated from the rhizome of Panax ginseng, exhibits potent proangiogenic activity and has the potential to be developed as a new angiotherapeutic agent. However, the mechanisms by which Rg1 promotes angiogenesis are not fully understood. Here, we show that Rg1 is an effective stimulator of HIF-1α under normal cellular oxygen conditions in human umbilical vein endothelial cells. HIF-1α steady-state mRNA was not affected by Rg1. Rather, HIF-1α protein synthesis was stimulated by Rg1. This effect was associated with constitutive activation of phosphatidylinositol 3-kinase (PI3K)/Akt and its effector p70 S6 kinase (p70(S6K)), but not extracellular-signal regulated kinase 1/2. We further revealed that HIF-1α induction triggered the expression of target genes, including vascular endothelial growth factor (VEGF). The use of small molecule inhibitors LY294002 or rapamycin to inhibit PI3K/Akt and p70(S6K) activities, respectively, resulted in diminished HIF-1α activation and subsequent VEGF expression. RNA interference-mediated knockdown of HIF-1α suppressed Rg1-induced VEGF synthesis and angiogenic tube formation, confirming that the effect was HIF-1α specific. Similarly, the angiogenic phenotype could be reversed by inhibition of PI3K/Akt and p70(S6K). These results define a hypoxia-independent activation of HIF-1α, uncovering a novel mechanism for Rg1 that could play a major role in angiogenesis and vascular remodeling.

The configuration and attachment of the utricular and saccular maculae to the temporal bone. New evidence from microtomography-CT studies of the membranous labyrinth.

High-resolution X-ray microtomography (micro-CT) was used to show the spatial configuration of the membranous labyrinth of the fixed guinea pig and human inner ear. Whole temporal bones were en bloc stained in 2% osmium tetroxide for 2 days or more to allow the osmium to attach to the membranes of the inner ear, and then scanned with a Skyscan 1172 micro-CT with highest resolution of 8 microns. The scans were segmented and reconstructed. The findings for guinea pigs and humans are similar. The saccular macula is closely attached to the curved medial wall of the temporal bone, but in both human and guinea pig the utricular macula is attached to the temporal bone only at the anterior region of the macula, and, as others have reported previously, much of the caudal area of the utricular macula is tenuously supported by a thin membrane, just above the dorsal margin of the stapes. This tenuous support may have important consequences for the sensing of forces by the utricular macula. Combining information from a dissected human horizontal canal with CT images allows an estimate of the orientation of the horizontal canal crista in human subjects, data which are necessary for treatment of benign paroyxsmal positional vertigo of the horizontal canal. The very high resolution achieved by micro-CT shows that reconstruction from inadequately sampled CT data produces images that are not anatomically correct, so that canal deformations and aplasias may appear to be present.