Preparation of an aptamer based organic-inorganic hybrid monolithic column with gold nanoparticles as an intermediary for the enrichment of proteins.

A novel strategy for the preparation of an aptamer based organic-inorganic hybrid affinity monolithic column was developed successfully using gold nanoparticles (GNPs) as an intermediary for a sandwich structure to realize the functional modification of the surface of the monolithic matrix. This monolithic matrix was facilely pre-synthesized via one-step co-condensation. Due to the high surface-to-volume ratio of GNPs and the large specific surface area of the hybrid matrix, the average coverage density of aptamers on the hybrid monolith reached 342 pmol µL(-1). With the combination of an aptamer based hybrid affinity monolithic column and enzymatic chromogenic assay, the quantitation and detection limits of thrombin were as low as 5 nM and 2 nM, respectively. These results indicated that the GNPs attached monolith provided a novel technique to immobilize aptamers on an organic-inorganic hybrid monolith and it could be used to achieve highly selective recognition and determination of trace proteins.

Evaluation of Vessel Sealing Performance Among Ultrasonic Devices in a Porcine Model.

BACKGROUND: As new technologies emerge, it is imperative to define which new devices are most likely to provide a reproducible, effective result for the patient and surgeon. The purpose of our study was to analyze 3 commercially available ultrasonic energy devices; the Sonicision (SC), the Harmonic ACE (HA), and the THUNDERBEAT (TB). MATERIAL AND METHODS: Eight female Yorkshire pigs were used for data collection and vessel harvest. Three devices were evaluated and compared with each other with respect to seal failure and cutting speed in vivo. After vessel harvest, one end of the fragment was sent for histological evaluation, and the other was used for burst pressure measurement testing in a blinded fashion. The coagulation and cut levels of all the generators were set up at a similar and constant level. RESULTS: Eighty-four vessels (47 arteries and 37 veins) were tested. Mean vessel diameter was equal among the groups. Cutting speed was significantly faster with TB (3.4 ± 0.7 seconds) than SC or HA (5.8 ± 2.4 and 6.1 ± 3.1 seconds; P < .0001). Burst pressure trended higher after ligation with TB (505.4 ± 349.4 mm Hg) than SC and HA (435.8 ± 403.0 and 437.6 ± 291.3 mm Hg). There were 2 seal failures in the SC group and HA group and none in the TB group. Histologically, the perpendicular width of tissue seal with TB (1.250 ± 0.55 mm) was significantly longer than that of the SC and the HA (0.772 ± 0.23 and 0.686 ± 0.23 mm; P < .0001). CONCLUSIONS: TB has proven to provide the most rapid and reliable seal. Therefore, TB may be safer and may decrease time during surgical procedures.

Endoscopic treatment for Bouveret syndrome.

BACKGROUND: Gallstone ileus is an uncommon cause for small bowel obstruction. Less than 3 % of cases are due to a gallstone impacted in the duodenum or pylorus resulting in a gastric outlet obstruction, described by Bouveret in 1896. Most of the successful therapeutic maneuvers described involve open surgical removal of the stone through either a gastrotomy or duodenotomy, and reported morbidity is not insignificant. Endoscopic techniques continue to evolve, allowing for more complex procedures and avoidance of open surgery and its accompanying high morbidity. This video displays a rarely used endoscopic method of relieving gastric outlet obstruction caused by a stone in a patient with Bouveret syndrome. METHODS: Video of successful endoscopic retrieval of a gallstone lodged in the pylorus is presented. An endoscopic retrieval basket is used, and key maneuvers highlighted include passage of the closed device distal to the stone, opening of the basket, and withdrawal of the stone under direct vision. RESULTS: After successful retrieval, endoscopic inspection revealed a normal duodenum and relief of the obstruction. Cholecystectomy was not performed, given that most cholecystoduodenal fistulae are large and will spontaneously close, especially if a patent cystic duct is present. Liver function tests were normal postoperatively, so no further evaluation of the bile duct was necessary. CONCLUSIONS: With new advances in technology, the endoscopic approach should be considered as the first line of treatment for cases of Bouveret syndrome because most patients are elderly with multiple comorbidities.

Circular dichroism spectroscopy study of crystalline-to-amorphous transformation in chiral platinum(II) complexes.

Two couples of enantiomeric platinum(II) complexes: Pt(L1a )Cl (1a), Pt(L1b )Cl (1b) and Pt(L1a )(C ≡ C - Ph) (2a), Pt(L1b )(C ≡ C - Ph) (2b) (L1a = (+)-1,3-di-(2-(4,5-pinene)pyridyl)benzene, L1b = (-)-1,3-di-(2-(4,5-pinene)pyridyl)benzene) were synthesized and characterized. Their absolute configurations were determined by single crystal X-ray diffraction and further verified by circular dichroism (CD) spectra (including electronic circular dichroism [ECD] and vibrational circular dichroism [VCD]). These complexes show interesting mechanoluminescence and/or vapoluminescence due to crystalline-to-amorphous transformation. The crystalline solids, grinding-induced amorphous powders, and vapor-induced amorphous powders of complexes 2a and 2b were comparatively investigated by solid-state ECD and VCD spectra. The transformation from crystalline solids to amorphous powders was accompanied by significant variances of the spectral feature in both ECD and VCD spectra.

Temporal bone dissection for neurosurgery residents: identifying the essential concepts and fundamental techniques for success.

BACKGROUND: Many contemporary neurosurgery residents, cordoned by work hour restrictions and drawn to newer technologies such as endovascular therapy, lack the proper direction necessary to learn the essentials of temporal bone dissection. A thorough knowledge of temporal bone anatomy combined with guidance regarding proper surgical technique makes temporal bone dissection an efficacious and fundamental learning activity. There is currently no concise guide for neurosurgical training programs to use in teaching the essentials of this dissection. METHODS: Over several years, the authors worked with neurosurgery residents to determine the key concepts necessary to gain a fundamental working knowledge of temporal bone dissection. RESULTS: We have identified 5 essential surgical principles and developed a step-by-step dissection technique useful for neurosurgery residents. CONCLUSIONS: Using this template, neurosurgery residents can make the most of their time in the skull base laboratory, becoming familiar with relevant temporal bone anatomy in situ and becoming facile with the surgical techniques necessary for its safe dissection.

Transzygomatic extended middle fossa approach for upper petroclival skull base lesions.

Central skull base lesions in the upper retroclival and petroclival regions can be challenging to access because of their location anterior to the brainstem. Several transpetrosal approaches have been developed to access the petroclival junction, including anterior petrosal (anterior petrosectomy), posterior petrosal (retrolabyrinthine, translabyrinthine, transcochlear), and combined petrosal approaches. The anterior petrosal approach is best suited for upper petroclival lesions located anterior and superior to the internal auditory canal and superior to the inferior petrosal sinus. This approach provides direct access to the anteromedial cerebellopontine angle, petrous apex, Meckel cave, and ventrolateral brainstem between the trigeminal root and the facial nerve. The authors describe their modification of an anterior petrosal approach, the so-called transzygomatic extended middle fossa approach, which incorporates a zygomatic osteotomy, anterior mobilization of the V3, and extensive middle fossa drilling. This exposure provides a wider surgical corridor for direct view of the clivus and ventral brainstem.

An Artificial Cadaveric Leg Blood Flow System for Endoscopic Vein Harvesting Simulation.

Despite being the most common training model for endoscopic vein harvesting, cadaveric legs are limited by their absence of blood flow, resulting in a faded vascular appearance. Because the saphenous vein and the surrounding tissue seem less distinguishable, dissection of the saphenous vein and bipolar coagulation of its branches becomes increasingly inefficient and difficult. An inexpensive artificial blood flow system was developed to overcome this limitation. A cadaveric leg was thawed to a soft and yielding degree, and the saphenous vein was dissected medial and proximal to the medial malleolus. An artificial blood solution was prepared by dissolving 4% protein powder, red dye, and a contrast agent-for x-ray visualization-in saline. The solution was perfused through the saphenous vein and artery. The open ends of the vessels were temporarily clamped after the perfusion had been completed. Blood flow within the vessels was confirmed via angiography and endoscopic visualization of the leg's vessels. A bleeding effect was observed when the saphenous vein was perforated or when a vascular branch was transected. Conversely, a tight seal indicated successful bipolar coagulation of a branch, providing an objective, quantifiable assessment parameter. The artificial blood flow system helps overcome the limitations of the cadaveric leg, creating a more realistic and inexpensive model for endoscopic vein harvesting simulation training.

Aptamer-based organic-silica hybrid affinity monolith prepared via "thiol-ene" click reaction for extraction of thrombin.

A novel strategy for preparing aptamer-based organic-silica hybrid monolithic column was developed via "thiol-ene" click chemistry. Due to the large specific surface area of the hybrid matrix and the simplicity, rapidness and high efficiency of "thiol-ene" click reaction, the average coverage density of aptamer on the organic-silica hybrid monolith reached 420 pmol µL(-1). Human α-thrombin can be captured on the prepared affinity monolithic column with high specificity and eluted by NaClO4 solution. N-p-tosyl-Gly-Pro-Arg p-nitroanilide acetate was used as the sensitive chromogenic substrate of thrombin. The thrombin enriched by this affinity column was detected with a detection of limit of 0.01 µM by spectrophotometry. Furthermore, the extraction recovery of thrombin at 0.15 µM in human serum was 91.8% with a relative standard deviation of 4.0%. These results indicated that "thiol-ene" click chemistry provided a promising technique to immobilize aptamer on organic-inorganic hybrid monolith and the easily-assembled affinity monolithic material could be used to realize highly selective recognition of trace proteins.

Imaging the cerebrovascular tree in the cadaveric head for planning surgical strategy.

OBJECTIVE: The objective of the study was to identify whether an integration of cadaveric dissections with preoperative imaging information may enable a better understanding of pathological anatomy, especially vascular lesions, and thus allow for greater precision in surgical planning. METHODS: We selected a computed tomographic contrast agent and experimentally determined the proportion of it that could mix compatibly with the silicone compound. The resultant mixture was injected into the cerebrovascular systems of six fresh human cadaveric heads. The specimens underwent computed tomography for the purpose of digital virtual exposures in parallel with laboratory dissections performed on these specimens. RESULTS: The 1:8 ratio of contrast agent to silicone rubber was determined to be appropriate for both computed tomography and subsequent laboratory dissection of the specimens. The blood vessels in computed tomographic scans demonstrated a higher attenuation than surrounding soft tissues. The opacity consistency of the injected vessels was a critical parameter for a clear three-dimensional rendering of the vascular structures in the natural surroundings of the skull base. Static and dynamic three-dimensional images of the cadaveric vascular tree were obtained as viewed through surgical corridors of various skull base approaches. CONCLUSION: We demonstrated a new cadaveric preparation model for imaging and dissection. This model allows for static and dynamic three-dimensional examination of the surgical anatomy from a neurosurgeon's perspective. It may facilitate the study of cerebrovascular system morphology/pathology in relation to the skull base as a tool for surgical planning.

Peroral endoscopic myotomy (POEM): feasible as reoperation following Heller myotomy.

PURPOSE: The purpose of this study was to demonstrate the feasibility of performing peroral endoscopic myotomy (POEM) in the management of recurrent achalasia after failed myotomy. METHODS: Eight patients presented to our institution between October 2010 and June 2013 with recurrent/persistent symptoms after prior laparoscopic Heller myotomy. Three patients underwent redo laparoscopic Heller myotomy, and five patients consented to redo myotomy with POEM. RESULTS: Demographics were similar between the groups with exception of age (POEM 69.5 vs. laparoscopic Heller myotomy (LHM) 34.5, p = 0.003). Preoperative Eckardt scores, motility, and prior interventions were not significantly different. Three patients who underwent POEM and two who underwent laparoscopic Heller myotomy had prior fundoplication. There was one perforation identified after laparoscopic Heller myotomy and one patient with persistent subcutaneous emphysema after POEM. Both POEM and laparoscopic Heller myotomy demonstrated significant improvement in symptoms and Eckardt scores at average follow-up of approximately 5 months (p < 0.05). CONCLUSION: POEM is a feasible option for patients after failed myotomy even in the presence of prior fundoplication. The procedure can be performed safely using a similar technique as for primary myotomy with the exception of creating the myotomy laterally along the right side of the esophagus and lesser curvature avoiding the previous anterior myotomy.

Transsphenoidal surgery for Cushing disease: experience with 136 patients.

BACKGROUND: This is a retrospective study of 136 patients with Cushing disease treated with transsphenoidal microsurgery. OBJECTIVE: To evaluate factors influencing immediate postoperative results and long-term outcomes. METHODS: Data regarding clinical presentation, endocrine evaluation, imaging studies, surgical technique, immediate postoperative biochemical remission (IPBR), and long-term results were entered into a database and analyzed statistically. IPBR was based on biochemical evidence of adrenal cortical insufficiency and clinical evidence of such insufficiency. RESULTS: IPBR for the entire series was 83.4%. In microadenomas, IPBR was 89.8% with a mean immediate postoperative plasma cortisol (IPPC) of 2.1 µg/dL (range, <0.5-5.3). Positive magnetic resonance imaging (MRI) was associated with 18 times greater odds of finding microadenoma at surgery (P < .001) and with 4.1 times greater odds of IPBR (P = .07). In patients with a negative MRI, a positive inferior petrosal sinus sampling (IPSS) test was associated with 93% of IPBR (P = .004). IPBR in macroadenomas was 30.7%. Of patients followed for 12 months or longer, 34.8% required glucocorticoid replacement for the duration of follow-up. The mean follow-up in microadenomas was 68.4 months with a 9.67% incidence of recurrences. The estimated actuarial incidence of recurrences increased with the passage of time and IPPC of greater than 2 µg/dL was associated with higher incidence of recurrences, although without statistical significance (P = .08). CONCLUSION: In microadenomas, a positive MRI and positive IPSS test were associated with a higher incidence of IPBR. Recurrences increased with the passage of time, and an IPPC of greater than 2 µg/dL may be associated with higher incidence of recurrences.

Advanced magnetic resonance imaging of cerebral cavernous malformations: part I. High-field imaging of excised human lesions.

OBJECTIVE: We hypothesized that structural details that have not been described previously would be revealed in cerebral cavernous malformations (CCM) through the use of high-field magnetic resonance and confocal microscopy. The structural details of CCMs excised from patients were sought by examination with high-field magnetic resonance imaging (MRI) and correlated with confocal microscopy of the same specimens. Novel features of CCM structure are outlined, including methodological limitations, venues for future research, and possible clinical implications. METHODS: CCM lesions excised from 4 patients were fixed in 2% paraformaldehyde and subjected to high-resolution MRI at 9.4 or 14.1-T by spin echo and gradient recalled echo methods. Histological validation of angioarchitecture was conducted on thick sections of CCM lesions using fluorescent probes to endothelium under confocal microscopy. RESULTS: Images of excised human CCM lesions were acquired with proton density-weighted, T1-weighted, T2-weighted spin echo, and T2*-weighted gradient recalled echo MRI. These images revealed large "bland" regions with thin-walled caverns and "honeycombed" regions with notable capillary proliferation and smaller caverns surrounding larger caverns. Proliferating capillaries and caverns of various sizes were also associated with the walls of apparent larger blood vessels in the lesions. Similar features were confirmed within thick sections of CCMs by confocal microscopy. MRI relaxation times in different regions of interest suggested the presence of different states of blood breakdown products in areas with apparent angiogenic proliferative activity. CONCLUSION: High-field MRI techniques demonstrate novel features of CCM angioarchitecture, visible at near histological resolution, including regions with apparently different biological activity. These preliminary observations will motivate future research, correlating lesion biological and clinical activity with features of MRI at higher field strength.

Advanced magnetic resonance imaging of cerebral cavernous malformations: part II. Imaging of lesions in murine models.

OBJECTIVE: We sought to assess the appearance of cerebral cavernous malformations (CCM) on magnetic resonance imaging (MRI) scans in murine Ccm1 and Ccm2 gene knockout models and to develop a technique of lesion localization for correlative pathobiological studies METHODS: Brains from 18 CCM mutant mice (Ccm1 Trp53 and Ccm2 Trp53) and 28 control animals were imaged by gradient recalled echo (T2*)-weighted MRI scans at 4.7- and 14.1-T in vivo and/or ex vivo. After MRI scanning, the brains were removed and stained with hematoxylin and eosin, and cells were laser-microdissected for molecular biological studies. RESULTS: T2*-weighted MRI scans of brains in vivo and ex vivo revealed lesions similar to human CCMs in mutant mice, but not in control animals. Stereotactic localization and hematoxylin and eosin staining of correlative tissue sections confirmed lesion histology and revealed other areas of dilated capillaries in the same brains. Some lesions were identified by MRI scans at 14.1-T, but not at 4.7-T. Polymerase chain reaction amplification from Ccm1 and beta-actin genes was demonstrated from nucleic acids extracted from laser microdissected lesional and perilesional cells. CONCLUSION: The high-field MRI techniques offer new opportunities for further investigation of disease pathogenesis in vivo, and the localization, staging, and histobiological dissection of lesions, including the presumed earliest stages of CCM lesion development.

Suboccipital retrosigmoid approach for removal of vestibular schwannomas: facial nerve function and hearing preservation.

In this report, we discuss the pertinent bony, arachnoid, and neurovascular anatomy of vestibular schwannomas that has an impact on the surgical technique for removal of these tumors, with the goal of facial nerve and hearing preservation. The surgical technique is described in detail starting with anesthesia, positioning, and neurophysiological monitoring and continuing with the exposure, technical nuances of tumor removal, hemostasis, and closure. Positive prognostic factors for hearing preservation are also highlighted.