The Experts below are selected from a list of 7572 Experts worldwide ranked by ideXlab platform
Thomas Minor - One of the best experts on this subject based on the ideXlab platform.
-
warm preflush with streptokinase improves microvascular procurement and tissue integrity in liver Graft retrieval from non heart beating donors
Transplantation, 2000Co-Authors: Junichiro Yamauchi, S Richter, Brigitte Vollmar, Michael D Menger, Thomas MinorAbstract:Background Apart from the warm ischemic insult, integrity of liver Grafts from non-heart-beating donors (NHBD) is additionally affected by microvascular alterations including erythrocyte aggregation and thrombus formation, which might hamper appropriate equilibration of the preservation solution to the Grafts' microvasculature precluding cold preservation. Thus, the objective of our study was to characterize microvascular Perfusion quality of University of Wisconsin (UW) solution during initial flushout of livers from NHBD rats, and to analyze the effects of an additional warm preflush with Ringer's lactated solution (RL) and with RL containing streptokinase (SK). Methods. Cardiocirculatory arrest was induced by phrenotomy. Subsequent to 30 min of warm ischemia, livers were perfused via an aortic catheter by gravity of 100 cm H 2 O either with 4°C 100 ml UW solution (UW, n=7), or with 25°C 30 ml RL preflush followed by 4°C 100 ml UW solution (RL+UW, n=7), or with 25°C 30 ml SK- (7500 IU) containing RL preflush and 4°C 100 ml UW solution (SK/RL+UW, n=6). Liver microPerfusion was quantified using in situ fluorescence epi-illumination microscopy. Liver microcirculation of sham-operated living animals (n=4) served as controls. Enzyme release after a 24-hr cold preservation period was used as an indicator of Graft integrity. Results. After 30 min of warm ischemia, microvascular Perfusion of UW solution was found markedly altered when compared with that of sham-operated living controls, as indicated by a significant reduction (P<0.05) of acinar and sinusoidal Perfusion. Preflush with RL (RL+UW) only slightly attenuated the acinar and sinusoidal Perfusion deficits, whereas the addition of SK to RL (SK/RL+UW) resulted in a significant improvement of microvascular Graft Perfusion (P<0.05). Accordingly, the increased enzyme release observed in solely UW-flushed livers after 24 hr cold preseravtion was only slightly influenced by preflush with RL, but markedly attenuated (P<0.05) by preflush with RL containing SK. Conclusion. The additive fibrinolytic therapy using SK is effective to improve microvascular procurement of livers after warm ischemia and may thus represent a promising approach to attenuate parenchymal cell injury in liver Graft retrieval from NHBD.
-
warm preflush with streptokinase improves microvascular procurement and tissue integrity in liver Graft retrieval from non heart beating donors
Transplantation, 2000Co-Authors: Junichiro Yamauchi, S Richter, Brigitte Vollmar, Michael D Menger, Thomas MinorAbstract:BACKGROUND Apart from the warm ischemic insult, integrity of liver Grafts from non-heart-beating donors (NHBD) is additionally affected by microvascular alterations including erythrocyte aggregation and thrombus formation, which might hamper appropriate equilibration of the preservation solution to the Grafts' microvasculature precluding cold preservation. Thus, the objective of our study was to characterize microvascular Perfusion quality of University of Wisconsin (UW) solution during initial flushout of livers from NHBD rats, and to analyze the effects of an additional warm preflush with Ringer's lactated solution (RL) and with RL containing streptokinase (SK). METHODS Cardiocirculatory arrest was induced by phrenotomy. Subsequent to 30 min of warm ischemia, livers were perfused via an aortic catheter by gravity of 100 cm H2O either with 4 degrees C 100 ml UW solution (UW, n=7), or with 25 degrees C 30 ml RL preflush followed by 4 degrees C 100 ml UW solution (RL+UW, n=7), or with 25 degrees C 30 ml SK- (7500 IU) containing RL preflush and 4 degrees C 100 ml UW solution (SK/RL+UW, n=6). Liver microPerfusion was quantified using in situ fluorescence epi-illumination microscopy. Liver microcirculation of sham-operated living animals (n=4) served as controls. Enzyme release after a 24-hr cold preservation period was used as an indicator of Graft integrity. RESULTS After 30 min of warm ischemia, microvascular Perfusion of UW solution was found markedly altered when compared with that of sham-operated living controls, as indicated by a significant reduction (P<0.05) of acinar and sinusoidal Perfusion. Preflush with RL (RL+UW) only slightly attenuated the acinar and sinusoidal Perfusion deficits, whereas the addition of SK to RL (SK/RL+UW) resulted in a significant improvement of microvascular Graft Perfusion (P<0.05). Accordingly, the increased enzyme release observed in solely UW-flushed livers after 24 hr cold preseravtion was only slightly influenced by preflush with RL, but markedly attenuated (P<0.05) by pre-flush with RL containing SK. CONCLUSION The additive fibrinolytic therapy using SK is effective to improve microvascular procurement of livers after warm ischemia and may thus represent a promising approach to attenuate parenchymal cell injury in liver Graft retrieval from NHBD.
Daniel Cherqui - One of the best experts on this subject based on the ideXlab platform.
-
indocyanine green fluorescence imaging to evaluate Graft Perfusion during liver transplantation
Hpb, 2019Co-Authors: Rodrigo Figueroa, Nicolas Golse, Fernando A Alvarez, Oriana Ciacio, Gabriella Pittau, Antonio Sa Cunha, Daniel CherquiAbstract:Abstract Background Primary Graft dysfunction (PGD) is a leading cause of Graft loss after liver transplantation. There is no reliable method to anticipate this complication intraoperatively. Indocyanine green (ICG) fluorescence imaging is a technique used in hepatobiliary surgery for detection of liver malignancies, but has never been reported in the setting of liver transplantation (LT) for function assessment. We hypothesized that there could be an association between the type of fluorescence and the occurrence of PGD. Methods We retrospectively analyzed 72 patients who underwent LT at our center. An assessment of the liver Graft with the ICG fluorescence technique was carried out. A classification comprising 3 types of fluorescence was created after evaluation of the recorded images. We assessed the relationship between the type of fluorescence and the occurrence of PGD. Results Crosstabulation analysis of the fluorescent types and occurrence of PGD yielded a statistically significant association (p = 0.002). Univariate analysis showed that an abnormal ICG fluorescence pattern was a risk factor for the occurrence of PGD after LT. Conclusions Our findings suggest that there could be an association between ICG fluorescence imaging and Graft function. This intraoperative tool could be useful to detect patients at risk of developing PGD after LT.
Michel M. Maharbiz - One of the best experts on this subject based on the ideXlab platform.
-
Monitoring deep-tissue oxygenation with a millimeter-scale ultrasonic implant
Nature Biotechnology, 2021Co-Authors: Soner Sonmezoglu, Jeffrey R. Fineman, Emin Maltepe, Michel M. MaharbizAbstract:Vascular complications following solid organ transplantation may lead to Graft ischemia, dysfunction or loss. Imaging approaches can provide intermittent assessments of Graft Perfusion, but require highly skilled practitioners and do not directly assess Graft oxygenation. Existing systems for monitoring tissue oxygenation are limited by the need for wired connections, the inability to provide real-time data or operation restricted to surface tissues. Here, we present a minimally invasive system to monitor deep-tissue O_2 that reports continuous real-time data from centimeter-scale depths in sheep and up to a 10-cm depth in ex vivo porcine tissue. The system is composed of a millimeter-sized, wireless, ultrasound-powered implantable luminescence O_2 sensor and an external transceiver for bidirectional data transfer, enabling deep-tissue oxygenation monitoring for surgical or critical care indications. The oxygenation of deep tissues is continuously measured using an ultrasound-powered wireless implant.
-
monitoring deep tissue oxygenation with a millimeter scale ultrasonic implant
bioRxiv, 2021Co-Authors: Soner Sonmezoglu, Jeffrey R. Fineman, Emin Maltepe, Michel M. MaharbizAbstract:Deep tissue oxygenation monitoring has many potential applications. Vascular complications after solid organ transplantation, for example, frequently lead to Graft ischemia, dysfunction or loss, and can occur months after transplantation. While imaging approaches can provide intermittent assessments of Graft Perfusion, they require highly skilled practitioners, and fail to directly assess Graft oxygenation. Existing tissue oxygen monitoring systems have many drawbacks, including the need for wired connections, the inability to provide real-time data, and, crucially, an operation that is limited to surface tissues. Here, we present the first wireless, minimally-invasive deep tissue oxygen monitoring system that provides continuous real-time data from centimeter-scale depths in a clinically-relevant large animal (sheep) model and demonstrates operation at great depths (up to 10 cm) through ex vivo porcine tissue. The system relies on a millimeter-sized, wireless, battery-free, implantable luminescence oxygen sensor that is powered by ultrasound and capable of bi-directional data transfer with an external transceiver. We present various aspects of system and sensor performance and demonstrate the operation of the system in vitro in distilled water, phosphate-buffered saline (PBS) and undiluted human serum, ex vivo through porcine tissue, and in vivo in a sheep model. We believe this technology represents a new class of diagnostic system particularly suitable for organ monitoring, as well as other surgical or critical care indications.
J. Kyselovic - One of the best experts on this subject based on the ideXlab platform.
-
The (R)-enantiomer of the 6-chromanol derivate SUL-121 improves renal Graft Perfusion via antagonism of the α-adrenoceptor
Scientific reports, 2019Co-Authors: D. Nakladal, H. Buikema, S. P. H. Lambooy, J. Bouma, G. Krenning, P. Vogelaar, A. C. Van Der Graaf, M. R. Groves, A. Reyes Romero, J. KyselovicAbstract:SUL-compounds are protectants from cold-induced ischemia and mitochondrial dysfunction. We discovered that adding SUL-121 to renal Grafts during warm machine rePerfusion elicits a rapid improvement in Perfusion parameters. Therefore, we investigate the molecular mechanisms of action in porcine intrarenal arteries (PIRA). Porcine kidneys were stored on ice overnight and Perfusion parameters were recorded during treatment with SUL-compounds. Agonist-induced vasoconstriction was measured in isolated PIRA after pre-incubation with SUL-compounds. Receptor binding and calcium transients were assessed in α1-adrenoceptor (α1-AR) transgenic CHO cells. Molecular docking simulation was performed using Schrodinger software. Renal pressure during warm rePerfusion was reduced by SUL-121 (-11.9 ± 2.50 mmHg) and its (R)-enantiomer SUL-150 (-13.2 ± 2.77 mmHg), but not by the (S)-enantiomer SUL-151 (-1.33 ± 1.26 mmHg). Additionally, SUL-150 improved renal flow (16.21 ± 1.71 mL/min to 21.94 ± 1.38 mL/min). SUL-121 and SUL-150 competitively inhibited PIRA contraction responses to phenylephrine, while other 6-chromanols were without effect. SUL-150 similarly inhibited phenylephrine-induced calcium influx and effectively displaced [7-Methoxy-3H]-prazosin in CHO cells. Docking simulation to the α1-AR revealed shared binding characteristics between prazosin and SUL-150. SUL-150 is a novel α1-AR antagonist with the potential to improve renal Graft Perfusion after hypothermic storage. In combination with previously reported protective effects, SUL-150 emerges as a novel protectant in organ transplantation.
-
The (R)-enantiomer of the 6-chromanol derivate SUL-121 improves renal Graft Perfusion via antagonism of the α1-adrenoceptor
Nature Publishing Group, 2019Co-Authors: D. Nakladal, H. Buikema, Reyes A. Romero, S. P. H. Lambooy, J. Bouma, G. Krenning, P. Vogelaar, A. C. Van Der Graaf, M. R. Groves, J. KyselovicAbstract:Abstract SUL-compounds are protectants from cold-induced ischemia and mitochondrial dysfunction. We discovered that adding SUL-121 to renal Grafts during warm machine rePerfusion elicits a rapid improvement in Perfusion parameters. Therefore, we investigate the molecular mechanisms of action in porcine intrarenal arteries (PIRA). Porcine kidneys were stored on ice overnight and Perfusion parameters were recorded during treatment with SUL-compounds. Agonist-induced vasoconstriction was measured in isolated PIRA after pre-incubation with SUL-compounds. Receptor binding and calcium transients were assessed in α1-adrenoceptor (α1-AR) transgenic CHO cells. Molecular docking simulation was performed using Schrödinger software. Renal pressure during warm rePerfusion was reduced by SUL-121 (−11.9 ± 2.50 mmHg) and its (R)-enantiomer SUL-150 (−13.2 ± 2.77 mmHg), but not by the (S)-enantiomer SUL-151 (−1.33 ± 1.26 mmHg). Additionally, SUL-150 improved renal flow (16.21 ± 1.71 mL/min to 21.94 ± 1.38 mL/min). SUL-121 and SUL-150 competitively inhibited PIRA contraction responses to phenylephrine, while other 6-chromanols were without effect. SUL-150 similarly inhibited phenylephrine-induced calcium influx and effectively displaced [7-Methoxy-3H]-prazosin in CHO cells. Docking simulation to the α1-AR revealed shared binding characteristics between prazosin and SUL-150. SUL-150 is a novel α1-AR antagonist with the potential to improve renal Graft Perfusion after hypothermic storage. In combination with previously reported protective effects, SUL-150 emerges as a novel protectant in organ transplantation
Junichiro Yamauchi - One of the best experts on this subject based on the ideXlab platform.
-
warm preflush with streptokinase improves microvascular procurement and tissue integrity in liver Graft retrieval from non heart beating donors
Transplantation, 2000Co-Authors: Junichiro Yamauchi, S Richter, Brigitte Vollmar, Michael D Menger, Thomas MinorAbstract:Background Apart from the warm ischemic insult, integrity of liver Grafts from non-heart-beating donors (NHBD) is additionally affected by microvascular alterations including erythrocyte aggregation and thrombus formation, which might hamper appropriate equilibration of the preservation solution to the Grafts' microvasculature precluding cold preservation. Thus, the objective of our study was to characterize microvascular Perfusion quality of University of Wisconsin (UW) solution during initial flushout of livers from NHBD rats, and to analyze the effects of an additional warm preflush with Ringer's lactated solution (RL) and with RL containing streptokinase (SK). Methods. Cardiocirculatory arrest was induced by phrenotomy. Subsequent to 30 min of warm ischemia, livers were perfused via an aortic catheter by gravity of 100 cm H 2 O either with 4°C 100 ml UW solution (UW, n=7), or with 25°C 30 ml RL preflush followed by 4°C 100 ml UW solution (RL+UW, n=7), or with 25°C 30 ml SK- (7500 IU) containing RL preflush and 4°C 100 ml UW solution (SK/RL+UW, n=6). Liver microPerfusion was quantified using in situ fluorescence epi-illumination microscopy. Liver microcirculation of sham-operated living animals (n=4) served as controls. Enzyme release after a 24-hr cold preservation period was used as an indicator of Graft integrity. Results. After 30 min of warm ischemia, microvascular Perfusion of UW solution was found markedly altered when compared with that of sham-operated living controls, as indicated by a significant reduction (P<0.05) of acinar and sinusoidal Perfusion. Preflush with RL (RL+UW) only slightly attenuated the acinar and sinusoidal Perfusion deficits, whereas the addition of SK to RL (SK/RL+UW) resulted in a significant improvement of microvascular Graft Perfusion (P<0.05). Accordingly, the increased enzyme release observed in solely UW-flushed livers after 24 hr cold preseravtion was only slightly influenced by preflush with RL, but markedly attenuated (P<0.05) by preflush with RL containing SK. Conclusion. The additive fibrinolytic therapy using SK is effective to improve microvascular procurement of livers after warm ischemia and may thus represent a promising approach to attenuate parenchymal cell injury in liver Graft retrieval from NHBD.
-
warm preflush with streptokinase improves microvascular procurement and tissue integrity in liver Graft retrieval from non heart beating donors
Transplantation, 2000Co-Authors: Junichiro Yamauchi, S Richter, Brigitte Vollmar, Michael D Menger, Thomas MinorAbstract:BACKGROUND Apart from the warm ischemic insult, integrity of liver Grafts from non-heart-beating donors (NHBD) is additionally affected by microvascular alterations including erythrocyte aggregation and thrombus formation, which might hamper appropriate equilibration of the preservation solution to the Grafts' microvasculature precluding cold preservation. Thus, the objective of our study was to characterize microvascular Perfusion quality of University of Wisconsin (UW) solution during initial flushout of livers from NHBD rats, and to analyze the effects of an additional warm preflush with Ringer's lactated solution (RL) and with RL containing streptokinase (SK). METHODS Cardiocirculatory arrest was induced by phrenotomy. Subsequent to 30 min of warm ischemia, livers were perfused via an aortic catheter by gravity of 100 cm H2O either with 4 degrees C 100 ml UW solution (UW, n=7), or with 25 degrees C 30 ml RL preflush followed by 4 degrees C 100 ml UW solution (RL+UW, n=7), or with 25 degrees C 30 ml SK- (7500 IU) containing RL preflush and 4 degrees C 100 ml UW solution (SK/RL+UW, n=6). Liver microPerfusion was quantified using in situ fluorescence epi-illumination microscopy. Liver microcirculation of sham-operated living animals (n=4) served as controls. Enzyme release after a 24-hr cold preservation period was used as an indicator of Graft integrity. RESULTS After 30 min of warm ischemia, microvascular Perfusion of UW solution was found markedly altered when compared with that of sham-operated living controls, as indicated by a significant reduction (P<0.05) of acinar and sinusoidal Perfusion. Preflush with RL (RL+UW) only slightly attenuated the acinar and sinusoidal Perfusion deficits, whereas the addition of SK to RL (SK/RL+UW) resulted in a significant improvement of microvascular Graft Perfusion (P<0.05). Accordingly, the increased enzyme release observed in solely UW-flushed livers after 24 hr cold preseravtion was only slightly influenced by preflush with RL, but markedly attenuated (P<0.05) by pre-flush with RL containing SK. CONCLUSION The additive fibrinolytic therapy using SK is effective to improve microvascular procurement of livers after warm ischemia and may thus represent a promising approach to attenuate parenchymal cell injury in liver Graft retrieval from NHBD.
