Signals from the Deep: Reach-Related Activity in the Human Superior Colliculus

Neurophysiological studies in nonhuman species indicated that neurons in the superior colliculus (SC) are involved in the control of upper limb movements. These findings suggested that the SC represents a crucial hub in a general sensorimotor network, including skeletomotor as much as oculomotor functions. In contrast to the SC in the various animal models, the human SC is largely unknown territory. In particular, it is unknown whether findings of reach-related activity in the nonhuman SC can be extrapolated to humans. Using fMRI we found signal increases at superficial/intermediate and deep locations at the SC during the execution of arm movements. In contrast, signals related to saccade execution were confined to the superficial and intermediate locations. Although targets for reaching were presented in the left and right hemifields under central fixation, we found a lateralization of reach-related signals with respect to the active arm. In contrast, saccade-related activity was bilateral, in agreement with the bilateral target presentation and the resulting directions of saccades. Our results suggest that the human SC not only contributes to the coordination of eye movements and spatial shifts of attentions but also to the sensorimotor control of arm movements.</jats:p

Evaluation of Efficacy of a New Cryoprobe for Transbronchial Cryobiopsy: A Randomized, Controlled in vivo Animal Study

&lt;b&gt;&lt;i&gt;Background:&lt;/i&gt;&lt;/b&gt; Forceps biopsy (FB) is still the most popular procedure for the bronchoscopic sampling of lung tissue. However, it has limitations like inadequate sample size and crush artifacts. Cryobiopsy (CB) has been introduced to obtain bronchoscopic biopsies with improved diagnostic yield compared to FB. Limitations of CB are the need to retract the cryoprobe en bloc with bronchoscope because samples are larger than the working channel and the variations of the freezing power of the reusable CB (rCB). Therefore, 3 new disposable cryoprobes (dCB) have been developed with different outer diameters: 1.1 mm (CB11-S) that can be retracted through the working channel of the bronchoscope, 1.7 mm (CB17) and 2.4 mm (CB24n), respectively. &lt;b&gt;&lt;i&gt;Objectives:&lt;/i&gt;&lt;/b&gt; The aim was to evaluate the new cryoprobes with regard to feasibility, specimen area, specimen quality and complications. &lt;b&gt;&lt;i&gt;Methods:&lt;/i&gt;&lt;/b&gt; We compared biopsy samples of the new probes with those obtained by FB and by rCB in an in vivo (porcine) model. A flexible bronchoscope was used to perform biopsy at 4 different locations at the upper and lower lobes of the right and left lung, respectively. The biopsies were taken under fluoroscopic control. The biopsy tool and activation times were allocated randomly. Altogether 204 biopsy procedures were performed. &lt;b&gt;&lt;i&gt;Results:&lt;/i&gt;&lt;/b&gt; The sample quality of the dCB was superior to that of FB (all &lt;i&gt;p&lt;/i&gt; &amp;#x3c; 0.05) and not significantly different to the rCB sample quality. Mean specimen sample area of all CB was significantly larger compared to FB (&lt;i&gt;p&lt;/i&gt; &amp;#x3c; 0.05). The sample area of the small cryoprobe (CB11-S) was significantly smaller compared to the other CB probes (&lt;i&gt;p&lt;/i&gt; &amp;#x3c; 0.05). No severe bleedings occurred. Pneumothoraces were detected in 3 of the 7 pigs. &lt;b&gt;&lt;i&gt;Conclusion:&lt;/i&gt;&lt;/b&gt; We conclude that CB with the new single-use instruments are feasible and represent a viable option to improve the diagnostic accuracy of histopathological evaluation compared to FB.</jats:p

Novel Techniques to Improve Precise Cell Injection

We noted recently that the injection of cells with a needle through a cystoscope in the urethral sphincter muscle of pigs failed to deposit them nearby or at the intended target position in about 50% of all animals investigated (n &gt; 100). Increasing the chance for precise cell injection by shotgun approaches employing several circumferential injections into the sphincter muscle bears the risk of tissue injury. In this study, we developed and tested a novel needle-free technique to precisely inject cells in the urethral sphincter tissue, or other tissues, using a water-jet system. This system was designed to fit in the working channels of endoscopes and cystoscopes, allowing a wide range of minimally invasive applications. We analyze key features, including the physical parameters of the injector design, pressure ranges applicable for tissue penetration and cell injections and biochemical parameters, such as different compositions of injection media. Our results present settings that enable the high viability of cells post-injection. Lastly, the method is suitable to inject cells in the superficial tissue layer and in deeper layers, required when the submucosa or the sphincter muscle of the urethra is targeted.</jats:p

Novel Techniques to Improve Precise Cell Injection

We noted recently that the injection of cells with a needle through a cystoscope in the urethral sphincter muscle of pigs failed to deposit them nearby or at the intended target position in about 50% of all animals investigated (n &gt; 100). Increasing the chance for precise cell injection by shotgun approaches employing several circumferential injections into the sphincter muscle bears the risk of tissue injury. In this study, we developed and tested a novel needle-free technique to precisely inject cells in the urethral sphincter tissue, or other tissues, using a water-jet system. This system was designed to fit in the working channels of endoscopes and cystoscopes, allowing a wide range of minimally invasive applications. We analyze key features, including the physical parameters of the injector design, pressure ranges applicable for tissue penetration and cell injections and biochemical parameters, such as different compositions of injection media. Our results present settings that enable the high viability of cells post-injection. Lastly, the method is suitable to inject cells in the superficial tissue layer and in deeper layers, required when the submucosa or the sphincter muscle of the urethra is targeted

Improving the quality of human upper urinary tract specimens by cryobiopsy

Objective: The quality of histopathological specimens obtained from the upper urinary tract with conventional flexible ureterorenoscopic biopsy needs to be improved. We investigated the feasibility and biopsy quality of specimens obtained by cryobiopsy, compared with standard ureterorenoscopic biopsy techniques in a human ex vivo model. Materials and Methods: Human ureters obtained from nephrectomy specimens (N=12) were dissected and canulated with an ureteral access sheath. Ureterorenoscopic biopsies were randomly obtained from different sites of the renal pelvic caliceal system using different types of instruments. The performance of two newly developed flexible cryoprobes with outer diameters of 1.1 mm (CB11) and 0.9 mm (CB09) was compared with that of the biopsy forceps(FB) and Bigopsy®(BiG) and two different Dormia baskets N‐Gage (NG) and Zero‐Tip (ZT). We assessed the feasibility of the various biopsy techniques based on the number of biopsy attempts needed to obtain macroscopically discernible biopsies. The specimens were examined histopathologically for size, biopsy quality, presence of various artifact types, and representativeness. Results: Biopsies taken with the cryoprobes showed a higher biopsy quality than biopsies taken with the comparative instruments. The CB11 provided significantly larger biopsies than forceps biopsies and also than biopsies with ZT. The CB09 was able to collect larger samples when compared with the FB and BiG biopsy forceps. There were no significant differences in artifact area, except for the CB11 cryoprobe compared with the NG. To clarify the results a subdivision of larger or smaller than 20% artifact area was performed. A significant difference was found between CB11 and the forceps biopsies, as well as between CB11 and NG and ZT in favor of the cryoprobe. The representation of the histopathological sample was also determined. Biopsies taken with CB11 were more representative compared with forceps biopsies BiG and FB and basket biopsies NG and ZT. Conclusions: In a standardized comparative ex vivo setting, larger biopsies were obtained by using the cryobiopsy technique with the CB11 probe. Qualitatively, cryobiopsy specimens were overlaid by fewer artifacts and a higher biopsy quality was achieved in histopathologic examination compared with standard instrumentation. Further stepwise development will transfer the promising cryobiopsy technique into the clinical setting