Minimally invasive monitoring of the central nervous system

Please click Additional Files below to see the full abstract

Morphological evaluation of experimental autologous rectus fascia sheath vascular grafts used for arterial replacement in a dog model

Although experimental autologous patch or tubular conduit vascular grafts made from the internal rectus fascia sheath (IRFS) have been reported in the literature, thorough morphological evaluation and verification of the histological arterialisation of such grafts are lacking. Four purpose-bred Beagle dogs were utilised to create eight arterial internal rectus fascia sheath (ARFS) grafts implanted between bisected ends of the external iliac arteries. Four out of the eight ARFS grafts were patent after three months. Haematoxylin-eosin and Azan staining verified that the grafts gained a vessel-like layered structure with the presence of large amounts of collagen fibres. Although the inner surface of the intact IRFS was originally covered with claudin-5-negative and pancytokeratin-positive mesothelial cells in control samples, the internal cells of the ARFS grafts became claudin-5 positive and pancytokeratin negative like in intact arteries. Spindle-shaped cells of the wall of ARFS grafts were α-smooth muscle actin (α-SMA) positive just like the smooth muscle cells of intact arteries, but α-SMA immunoreactivity was negative in the intact IRFS. According to these findings, the fibroblast cells of the ARFS graft have changed into myofibroblast cells. The study has proved that ARFS grafts may be used as an alternative in arterial replacement, since the graft becomes morphologically and functionally similar to the host vessel via arterialisation

Erdbebenbelastung auf Offshorebauwerke Schlussbericht

The objective of the R and D-project 'Earthquake Loading on Offshore Structures' is the development of a practically applicable and code conforming design concept for Concrete Offshore Monotowers. The hydrodynamic analysis has been carried out by the Technical University of Hamburg Harburg, Department of Offshore Technology II (TUHH, Arbeitsgebiet Meerestechnik II). The structural design concept has been developed by the Technical Staff of Bilfinger and Berger Bauaktiengesellschaft in Cooperation with the Gesellschaft fuer Schwingungsuntersuchungen und dynamische Pruefmethoden mbH in Mannheim. As the main results of the research project the following is available: 1. Easy to use graphic solutions for the hydrodynamic actions and fluid-structure-interaction of monotowers of arbitrary geometrical shape, 2. A consistent design concept, where fluid-structure-interaction is implemented in a determination of earthquake effects by the widely used method of design response spectra. Besides some basic investigations into the mechanics of fluid actions on earthquake excited bodies especailly the importane of the earthquake for the design of the structure has been analysed by so called earthquake factors. In addition neighbouring problems of fluid structure interaction of liquid storage tanks and arch dams has been discussed. This final report contains a comprehensive description of the results of the work. Previously released intermediate reports as well as publications and presentations from the project are included in the appendix. (orig.)Das Ziel des Forschungsprojektes Erdbebenbelastung von Offshorebauwerken war die Entwicklung eines praxisgerechten und normenkonformen Konzepts fuer die Bemessung von Offshore-Beton-Monotowern. Die hydrodynamische Analyse wurde von der TUHH, Arbeitsgebiet Meerestechnik II, erarbeitet, waehrend das Bemessungskonzept im Technischen Buero von Bilfinger und Berger Bauaktiengesellschaft in Zusammenarbeit mit der Gesellschaft fuer Schwingungsuntersuchungen und dynamische Pruefmethoden mbH in Mannheim entwickelt wurde. Als wesentliche Arbeitsergebnisse liegt nunmehr vor: 1. Uebersichtsgrafiken fuer die Abschaetzung der Wasserwirkung auf Bauwerke im Frequenzbereich von Erdbeben fuer variable Geometrie zusammengesetzter Zylinder, 2. ein konsistentes Bemessungskonzept, in welchem die Bauwerks-Wasserwechselwirkung bei einer Bemessung mit Antwortspektren beruecksichtigt werden kann. Neben einigen Untersuchungen zur mechanischen Problematik wurde auch die Beurteilung der Relevanz des Lastfalles Erdbeben anhand von bauteilbezogenen Erdbebenfaktoren beschrieben, sowie ein Hinweis auf die Behandlung der benachbarten Problemstellung bei fluessigkeitsgefuellten Behaeltern und Bogenstaumauern gegeben. Der Schlussbericht enthaelt eine umfassende Darstellung der Arbeitsergebnisse des Forschungsprojektes. Abgeschlossene Teilberichte sowie Veroeffentlichungen aus dem Forschungsprojekt sind im Anhang zusammengefasst. (orig.)Available from TIB Hannover: F95B1255+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Morphine and anandamide stimulate intracellular calcium transients in human arterial endothelial cells: coupling to nitric oxide release

Both morphine and anandamide significantly stimulated cultured endothelial intracellular calcium level increases in a concentration-dependent manner in cells pre-loaded with fura 2/AM. Morphine is more potent than anandamide (approximately 275 vs. 135 nM [Ca]i), and the [Ca]i for both ligands was blocked by prior exposure of the cells to their respective receptor antagonist, i.e., naloxone and SR 171416A. Various opioid peptides did not exhibit this ability, indicating a morphine-mu3-mediated process. In comparing the sequence of events concerning morphine's and anandamide's action in stimulating both [Ca]i and nitric oxide production in endothelial cells, we found that the first event precedes the second by 40+/-8 sec. The opiate and cannabinoid stimulation of [Ca]i was attenuated in cells leeched of calcium, strongly suggesting that intracellular calcium levels regulate cNOS activity

μ3 Opiate receptor expression in lung and lung carcinoma: ligand binding and coupling to nitric oxide release

The mu 3 opiate receptor subtype is expressed in human surgical specimens of both normal lung and non-small-cell lung carcinoma. Nitric oxide (NO) release is mediated through the mu 3 receptor, and in lung carcinoma, morphine-stimulated NO release is significantly higher and prolonged than in normal lung. Using reverse transcriptase-polymerase chain reaction (RT-PCR) and Southern blot analysis we show that specific mu opioid receptor transcripts are present in lung carcinoma and other cells with the mu 3 profile. Our findings identify a unique role for the mu 3 opiate receptor in opiate-mediated NO release and suggest that endogenous opiates, through their release of NO, may play a role in cancer progression

Optical monitoring and detection of spinal cord ischemia.

Spinal cord ischemia can lead to paralysis or paraparesis, but if detected early it may be amenable to treatment. Current methods use evoked potentials for detection of spinal cord ischemia, a decades old technology whose warning signs are indirect and significantly delayed from the onset of ischemia. Here we introduce and demonstrate a prototype fiber optic device that directly measures spinal cord blood flow and oxygenation. This technical advance in neurological monitoring promises a new standard of care for detection of spinal cord ischemia and the opportunity for early intervention. We demonstrate the probe in an adult Dorset sheep model. Both open and percutaneous approaches were evaluated during pharmacologic, physiological, and mechanical interventions designed to induce variations in spinal cord blood flow and oxygenation. The induced variations were rapidly and reproducibly detected, demonstrating direct measurement of spinal cord ischemia in real-time. In the future, this form of hemodynamic spinal cord diagnosis could significantly improve monitoring and management in a broad range of patients, including those undergoing thoracic and abdominal aortic revascularization, spine stabilization procedures for scoliosis and trauma, spinal cord tumor resection, and those requiring management of spinal cord injury in intensive care settings

Fiber-optic Monitoring of Spinal Cord Hemodynamics in Experimental Aortic Occlusion

BACKGROUND: Spinal cord ischemia occurs frequently during thoracic aneurysm repair. Current methods to detect ischemia, based upon electrophysiology techniques, are indirect, non-specific, and temporally slow. Here we report the testing of a spinal cord blood flow and oxygenation monitor, based on Diffuse Correlation and Optical Spectroscopies, during aortic occlusion in a sheep model. METHODS: Testing was carried out in sixteen Dorset sheep. Sensitivity in detecting spinal cord blood flow and oxygenation changes during aortic occlusion, pharmacologically induced hypotension and hypertension, and physiologically induced hypoxia/hypercarbia were assessed. Accuracy of the Diffuse Correlation Spectroscopy measurements was determined via comparison to microsphere blood flow measurements. Precision was assessed through repeated measurements in response to pharmacologic interventions. RESULTS: The fiber optic probe can be placed percutaneously, and is capable of continuously measuring spinal cord blood flow and oxygenation preoperatively, intraoperatively, and postoperatively. The device is sensitive to spinal cord blood flow and oxygenation changes associated with aortic occlusion, immediately detecting a fall in blood flow (−65 ± 32%, n=32) and blood oxygenation (−17 ± 13%, n=11) in 100% of trials. Comparison of spinal cord blood flow measurements by the device with microsphere measurements led to a correlation of R(2)=0.49, p<0.01 and the within-sheep coefficient of variation was 9.69%. Finally, Diffuse Correlation Spectroscopy is temporally more sensitive to ischemic interventions than motor evoked potentials. CONCLUSIONS: The first generation spinal fiber optic monitoring device offers a novel and potentially important step forward in the monitoring of spinal cord ischemia

Fiber-optic monitoring of spinal cord hemodynamics in experimental aortic occlusion

BACKGROUND: Spinal cord ischemia occurs frequently during thoracic aneurysm repair. Current methods to detect ischemia, based upon electrophysiology techniques, are indirect, non-specific, and temporally slow. Here we report the testing of a spinal cord blood flow and oxygenation monitor, based on Diffuse Correlation and Optical Spectroscopies, during aortic occlusion in a sheep model. METHODS: Testing was carried out in sixteen Dorset sheep. Sensitivity in detecting spinal cord blood flow and oxygenation changes during aortic occlusion, pharmacologically induced hypotension and hypertension, and physiologically induced hypoxia/hypercarbia were assessed. Accuracy of the Diffuse Correlation Spectroscopy measurements was determined via comparison to microsphere blood flow measurements. Precision was assessed through repeated measurements in response to pharmacologic interventions. RESULTS: The fiber optic probe can be placed percutaneously, and is capable of continuously measuring spinal cord blood flow and oxygenation preoperatively, intraoperatively, and postoperatively. The device is sensitive to spinal cord blood flow and oxygenation changes associated with aortic occlusion, immediately detecting a fall in blood flow (−65 ± 32%, n=32) and blood oxygenation (−17 ± 13%, n=11) in 100% of trials. Comparison of spinal cord blood flow measurements by the device with microsphere measurements led to a correlation of R(2)=0.49, p<0.01 and the within-sheep coefficient of variation was 9.69%. Finally, Diffuse Correlation Spectroscopy is temporally more sensitive to ischemic interventions than motor evoked potentials. CONCLUSIONS: The first generation spinal fiber optic monitoring device offers a novel and potentially important step forward in the monitoring of spinal cord ischemia

Fiber-optic monitoring of spinal cord hemodynamics in experimental aortic occlusion

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOBackground: Spinal cord ischemia occurs frequently during thoracic aneurysm repair. Current methods based on electrophysiology techniques to detect ischemia are indirect, non-specific, and temporally slow. In this article, the authors report the testing of a spinal cord blood flow and oxygenation monitor, based on diffuse correlation and optical spectroscopies, during aortic occlusion in a sheep model. Methods: Testing was carried out in 16 Dorset sheep. Sensitivity in detecting spinal cord blood flow and oxygenation changes during aortic occlusion, pharmacologically induced hypotension and hypertension, and physiologically induced hypoxia/hypercarbia was assessed. Accuracy of the diffuse correlation spectroscopy measurements was determined via comparison with microsphere blood flow measurements. Precision was assessed through repeated measurements in response to pharmacologic interventions. Results: The fiber-optic probe can be placed percutaneously and is capable of continuously measuring spinal cord blood flow and oxygenation preoperatively, intraoperatively, and postoperatively. The device is sensitive to spinal cord blood flow and oxygenation changes associated with aortic occlusion, immediately detecting a decrease in blood flow (-65 32%; n = 32) and blood oxygenation (-17 +/- 13%, n = 11) in 100% of trials. Comparison of spinal cord blood flow measurements by the device with microsphere measurements led to a correlation of R-2 = 0.49, P < 0.01, and the within-sheep coefficient of variation was 9.69%. Finally, diffuse correlation spectroscopy is temporally more sensitive to ischemic interventions than motor-evoked potentials. Conclusion: The first-generation spinal fiber-optic monitoring device offers a novel and potentially important step forward in the monitoring of spinal cord ischemia.Background: Spinal cord ischemia occurs frequently during thoracic aneurysm repair. Current methods based on electrophysiology techniques to detect ischemia are indirect, non-specific, and temporally slow. In this article, the authors report the testing of a spinal cord blood flow and oxygenation monitor, based on diffuse correlation and optical spectroscopies, during aortic occlusion in a sheep model. Methods: Testing was carried out in 16 Dorset sheep. Sensitivity in detecting spinal cord blood flow and oxygenation changes during aortic occlusion, pharmacologically induced hypotension and hypertension, and physiologically induced hypoxia/hypercarbia was assessed. Accuracy of the diffuse correlation spectroscopy measurements was determined via comparison with microsphere blood flow measurements. Precision was assessed through repeated measurements in response to pharmacologic interventions. Results: The fiber-optic probe can be placed percutaneously and is capable of continuously measuring spinal cord blood flow and oxygenation preoperatively, intraoperatively, and postoperatively. The device is sensitive to spinal cord blood flow and oxygenation changes associated with aortic occlusion, immediately detecting a decrease in blood flow (-65 32%n = 32) and blood oxygenation (-17 +/- 13%, n = 11) in 100% of trials. Comparison of spinal cord blood flow measurements by the device with microsphere measurements led to a correlation of R-2 = 0.49, P < 0.01, and the within-sheep coefficient of variation was 9.69%. Finally, diffuse correlation spectroscopy is temporally more sensitive to ischemic interventions than motor-evoked potentials. Conclusion: The first-generation spinal fiber-optic monitoring device offers a novel and potentially important step forward in the monitoring of spinal cord ischemia.123613621373FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP [2012/02500-8]2012/02500-8The authors thank the Biostatistical Consulting Core at Stony Brook University (Stony Brook, New York) for consulting with them on the statistical analysis. The authors also thank the veterinary technicians at the Division of Laboratory Animal Resources (DLAR) at Stony Brook University and Cecille Just, an electroencephalography (EEG) specialist, from the EEG Department at Stony Brook Hospital (Stony Brook, New York), for their assistance with their sheep experiments. This work has been supported by the Craig H. Neilsen Foundation (Encino, California)Stony Brook University Fusion Award (Stony Brook, New York)Stony Brook University’s Department of AnesthesiologyOffice of the Vice President for ResearchSchool of Medicine and University Hospital (Stony Brook, New Yorkto Drs. Floyd and Kogler)National Institutes of Health (Bethesda, Marylandgrant nos. R01-NS060653 and P41-EB015893 to Dr. Yodh)and the São Paulo Research Foundation through grant no. 2012/02500-8 (São Paulo, Brazilto Dr. Galler)