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Ceccato GHW, Foltran RS, Franke K, Lovato RM, Nicolato AA, Gusmão SNS, Oliveira MMR, Borba LAB. Two-Stage Pulsatile Human Placenta Model for Microvascular Anastomosis Training in Neurosurgery. World Neurosurg 2023; 179:185-196.e1. [PMID: 37690578 DOI: 10.1016/j.wneu.2023.08.118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 08/27/2023] [Accepted: 08/28/2023] [Indexed: 09/12/2023]
Abstract
OBJECTIVE The development of microsurgical skills is crucial for neurosurgical education. The human placenta is a promising model for practicing vascular anastomosis due to its similarities with brain vessels. We propose a 2-stage model for training in extracranial-to-intracranial anastomosis using the placenta. METHODS Initially, we propose practicing anastomosis in 2 adjacent placentas. Once successful, the procedure advances to a more challenging configuration that employs a 3-dimensionally printed skull with a window simulating a pterional craniotomy. It is positioned an intracranial placenta and an extracranial one, and the latter has a prominent vessel exposed toward the side of the craniotomy. Both placentas have one artery and vein cannulated in the umbilical cord, and we present an artificial placental circulation system for microvascular training that regulates pulsation and hydrodynamic pressure while keeping veins engorged with a pressurized bag. To verify anastomosis patency, we utilize sodium fluorescein and iodine contrast. RESULTS The 2-stage model simulated several aspects of microvascular anastomosis. Our perfusion system allowed for intraoperative adjustments of hydrodynamic pressure and pulsation. Using iodine contrast and fluorescein enabled proper evaluation of anastomosis patency and hydrodynamic features. CONCLUSIONS Training in the laboratory is essential for developing microsurgical skills. We have presented a model for microvascular anastomosis with artificial circulation and postoperative imaging evaluation, which is highly beneficial for enhancing the learning curve in microvascular procedures.
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Affiliation(s)
- Guilherme H W Ceccato
- Department of Neurosurgery, Mackenzie Evangelical University Hospital, Curitiba, PR, Brazil; Department of Neurosurgery, Rehabilitation Hospital Center Ana Carolina Moura Xavier, Curitiba, PR, Brazil
| | - Rodrigo S Foltran
- Department of Neurosurgery, Mackenzie Evangelical University Hospital, Curitiba, PR, Brazil; Department of Neurosurgery, Rehabilitation Hospital Center Ana Carolina Moura Xavier, Curitiba, PR, Brazil
| | - Kauê Franke
- Department of Neurosurgery, Mackenzie Evangelical University Hospital, Curitiba, PR, Brazil; Department of Neurosurgery, Rehabilitation Hospital Center Ana Carolina Moura Xavier, Curitiba, PR, Brazil
| | - Renan M Lovato
- Department of Neurosurgery, Santa Casa de São Paulo School of Medical Sciences, São Paulo, SP, Brazil; Department of Neurosurgery, Regional University Hospital of North of Paraná, Londrina, PR, Brazil
| | - Arthur A Nicolato
- Department of Anatomy, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Sebastiao N S Gusmão
- Department of Surgery, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Marcelo M R Oliveira
- Department of Surgery, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Luis A B Borba
- Department of Neurosurgery, Mackenzie Evangelical University Hospital, Curitiba, PR, Brazil; Department of Neurosurgery, Rehabilitation Hospital Center Ana Carolina Moura Xavier, Curitiba, PR, Brazil; Department of Neurosurgery, Federal University of Paraná, Curitiba, PR, Brazil.
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Bessen MA, Gayen CD, Quarrington RD, Walls AC, Leonard AV, Kurtcuoglu V, Jones CF. Characterising spinal cerebrospinal fluid flow in the pig with phase-contrast magnetic resonance imaging. Fluids Barriers CNS 2023; 20:5. [PMID: 36653870 PMCID: PMC9850564 DOI: 10.1186/s12987-022-00401-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 12/13/2022] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Detecting changes in pulsatile cerebrospinal fluid (CSF) flow may assist clinical management decisions, but spinal CSF flow is relatively understudied. Traumatic spinal cord injuries (SCI) often cause spinal cord swelling and subarachnoid space (SAS) obstruction, potentially causing pulsatile CSF flow changes. Pigs are emerging as a favoured large animal SCI model; therefore, the aim of this study was to characterise CSF flow along the healthy pig spine. METHODS Phase-contrast magnetic resonance images (PC-MRI), retrospectively cardiac gated, were acquired for fourteen laterally recumbent, anaesthetised and ventilated, female domestic pigs (22-29 kg). Axial images were obtained at C2/C3, T8/T9, T11/T12 and L1/L2. Dorsal and ventral SAS regions of interest (ROI) were manually segmented. CSF flow and velocity were determined throughout a cardiac cycle. Linear mixed-effects models, with post-hoc comparisons, were used to identify differences in peak systolic/diastolic flow, and maximum velocity (cranial/caudal), across spinal levels and dorsal/ventral SAS. Velocity wave speed from C2/C3 to L1/L2 was calculated. RESULTS PC-MRI data were obtained for 11/14 animals. Pulsatile CSF flow was observed at all spinal levels. Peak systolic flow was greater at C2/C3 (dorsal: - 0.32 ± 0.14 mL/s, ventral: - 0.15 ± 0.13 mL/s) than T8/T9 dorsally (- 0.04 ± 0.03 mL/s; p < 0.001), but not different ventrally (- 0.08 ± 0.08 mL/s; p = 0.275), and no difference between thoracolumbar levels (p > 0.05). Peak diastolic flow was greater at C2/C3 (0.29 ± 0.08 mL/s) compared to T8/T9 (0.03 ± 0.03 mL/s, p < 0.001) dorsally, but not different ventrally (p = 1.000). Cranial and caudal maximum velocity at C2/C3 were greater than thoracolumbar levels dorsally (p < 0.001), and T8/T9 and L1/L2 ventrally (p = 0.022). Diastolic velocity wave speed was 1.41 ± 0.39 m/s dorsally and 1.22 ± 0.21 m/s ventrally, and systolic velocity wave speed was 1.02 ± 0.25 m/s dorsally and 0.91 ± 0.22 m/s ventrally. CONCLUSIONS In anaesthetised and ventilated domestic pigs, spinal CSF has lower pulsatile flow and slower velocity wave propagation, compared to humans. This study provides baseline CSF flow at spinal levels relevant for future SCI research in this animal model.
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Affiliation(s)
- Madeleine Amy Bessen
- grid.1010.00000 0004 1936 7304Adelaide Spinal Research Group and Centre for Orthopaedics and Trauma Research, Adelaide Medical School, The University of Adelaide, Level 7, Adelaide Health and Medical Sciences Building, The University of Adelaide, North Terrace, Adelaide, SA 5005 Australia
| | - Christine Diana Gayen
- grid.1010.00000 0004 1936 7304Adelaide Spinal Research Group and Centre for Orthopaedics and Trauma Research, Adelaide Medical School, The University of Adelaide, Level 7, Adelaide Health and Medical Sciences Building, The University of Adelaide, North Terrace, Adelaide, SA 5005 Australia ,grid.1010.00000 0004 1936 7304Translational Neuropathology Laboratory, School of Biomedicine, The University of Adelaide, Level 2, Helen Mayo North Building, The University of Adelaide, Frome Road, Adelaide, SA 5005 Australia
| | - Ryan David Quarrington
- grid.1010.00000 0004 1936 7304Adelaide Spinal Research Group and Centre for Orthopaedics and Trauma Research, Adelaide Medical School, The University of Adelaide, Level 7, Adelaide Health and Medical Sciences Building, The University of Adelaide, North Terrace, Adelaide, SA 5005 Australia ,grid.1010.00000 0004 1936 7304School of Electrical and Mechanical Engineering, The University of Adelaide, North Terrace, Adelaide, SA 5005 Australia
| | - Angela Catherine Walls
- grid.430453.50000 0004 0565 2606Clinical and Research Imaging Centre, South Australian Health and Medical Research Institute, National Imaging Facility, Northern Pod, SAHMRI, North Terrace, Adelaide, SA 5000 Australia
| | - Anna Victoria Leonard
- grid.1010.00000 0004 1936 7304Translational Neuropathology Laboratory, School of Biomedicine, The University of Adelaide, Level 2, Helen Mayo North Building, The University of Adelaide, Frome Road, Adelaide, SA 5005 Australia
| | - Vartan Kurtcuoglu
- grid.7400.30000 0004 1937 0650Institute of Physiology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland ,grid.7400.30000 0004 1937 0650Zurich Center for Integrative Human Physiology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland ,grid.7400.30000 0004 1937 0650Neuroscience Center Zurich, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Claire Frances Jones
- grid.1010.00000 0004 1936 7304Adelaide Spinal Research Group and Centre for Orthopaedics and Trauma Research, Adelaide Medical School, The University of Adelaide, Level 7, Adelaide Health and Medical Sciences Building, The University of Adelaide, North Terrace, Adelaide, SA 5005 Australia ,grid.1010.00000 0004 1936 7304School of Electrical and Mechanical Engineering, The University of Adelaide, North Terrace, Adelaide, SA 5005 Australia ,grid.416075.10000 0004 0367 1221Department of Orthopaedics, Royal Adelaide Hospital, Adelaide, SA 5000 Australia
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Prather R, Divo E, Kassab A, DeCampli W. In-silico analysis of outflow graft implantation orientation and cerebral thromboembolism incidence for full LVAD support. Comput Methods Biomech Biomed Engin 2021; 25:1249-1261. [PMID: 34812689 DOI: 10.1080/10255842.2021.2005789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
We investigate tailoring cannula implantation angles of left ventricle assist devices (LVAD) to reduce cerebral embolism risk for full LVAD support. We resolve pulsatile hemodynamics with a multi-scale computational fluid dynamics model coupled to a Lagrangian scheme tracking 2-5 mm particles for three cannula implantations. Blood is modeled as non-Newtonian. Cerebral flow distribution is altered depending on anastomosis angle and comparison of means embolization rates between steady and unsteady flow models show that unsteady modeling is more accurate even in the full LVAD support case. Intermediate angle implantation yields lowest cerebral embolization incidence of 11% vs 29% for normal and 36% for shallow implantation.
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Affiliation(s)
- Ray Prather
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida, USA.,Department of Mechanical Engineering, Embry-Riddle Aeronautical University, Daytona Beach, Florida, USA.,Arnold Palmer Children's Hospital, Orlando Health, Orlando, Florida, USA
| | - Eduardo Divo
- Department of Mechanical Engineering, Embry-Riddle Aeronautical University, Daytona Beach, Florida, USA
| | - Alain Kassab
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida, USA
| | - William DeCampli
- Arnold Palmer Children's Hospital, Orlando Health, Orlando, Florida, USA.,College of Medicine, University of Central Florida, Orlando, Florida, USA
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Cheah E, Wu Z, Thakur SS, O'Carroll SJ, Svirskis D. Externally triggered release of growth factors - A tissue regeneration approach. J Control Release 2021; 332:74-95. [PMID: 33600882 DOI: 10.1016/j.jconrel.2021.02.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 02/10/2021] [Accepted: 02/11/2021] [Indexed: 12/22/2022]
Abstract
Tissue regeneration aims to achieve functional restoration following injury by creating an environment to enable the body to self-repair. Strategies for regeneration rely on the introduction of biomaterial scaffolding, cells and bioactive molecules into the body, at or near the injury site. Of these bioactive molecules, growth factors (GFs) play a pivotal role in directing regenerative pathways for many cell populations. However, the therapeutic use of GFs has been limited by the complexity of biological injury and repair, and the properties of the GFs themselves, including their short half-life, poor tissue penetration, and off-target side effects. Externally triggered delivery systems have the potential to facilitate the delivery of GFs into the target tissues with considerations of the timing, sequence, amount, and location of GF presentation. This review briefly discusses the challenges facing the therapeutic use of GFs, then, we discuss approaches to externally trigger GF release from delivery systems categorised by stimulation type; ultrasound, temperature, light, magnetic fields and electric fields. Overall, while the use of GFs for tissue regeneration is still in its infancy, externally controlled GF delivery technologies have the potential to achieve robust and effective solutions to present GFs to injured tissues. Future technological developments must occur in conjunction with a comprehensive understanding of the biology at the injury site to ensure translation of promising technologies into real world benefit.
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Affiliation(s)
- Ernest Cheah
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Zimei Wu
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Sachin S Thakur
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Simon J O'Carroll
- Department of Anatomy and Medical Imaging, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Darren Svirskis
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Martin L, Higgins L, Westwood M, Brownbill P. Pulsatility effects of flow on vascular tone in the fetoplacental circulation. Placenta 2020; 101:163-168. [PMID: 33002776 DOI: 10.1016/j.placenta.2020.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 08/25/2020] [Accepted: 09/01/2020] [Indexed: 02/05/2023]
Abstract
INTRODUCTION The regulation of vascular tone in the fetoplacental circulation is governed by endocrine and mechanical forces yielding a relaxed basal state in normal pregnancy. Flow mediated vasodilation, induced by shear stress and endothelial nitric oxide signalling, is key to driving vasorelaxation in this circulation. The pulsatile property of blood flow, as opposed to the flow rate, could provide an additional factor in this regulation, but its effects and signalling have never been explored in the fetoplacental microvasculature. METHODS Here, we studied the effects of non-pulsatile and pulsatile flow modalities on vascular resistance in the fetoplacental microcirculation of the human placenta using an ex vivo perfusion model; and examined a potential role for nitric oxide. We also explored whether the placental Doppler velocimetry waveform is sustained within subchorial arteries in vivo. RESULTS Pulsatile flow reduced basal impedance to flow during steady state perfusion compared to non-pulsatile flow, signalled through enhanced nitric oxide production. Doppler velocimetry waveforms were visible within the subchorial arteries in vivo. CONCLUSION This work suggests that the pulsatile property of flow through the fetoplacental circulation is sensed by the fetoplacental vasculature to mediate a signalling response and provide additional vasodilation of this microcirculation. We speculate that in pregnancy disease, altered amplitude and frequency of the subchorial pulse might impact on vascular function in a compromised high-resistance placental microcirculation.
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Affiliation(s)
- Laura Martin
- Maternal and Fetal Health Research Centre, Division of Developmental Biology & Medicine, School of Medical Sciences, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, M13 9WL, UK
| | - Lucy Higgins
- Maternal and Fetal Health Research Centre, Division of Developmental Biology & Medicine, School of Medical Sciences, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, M13 9WL, UK
| | - Melissa Westwood
- Maternal and Fetal Health Research Centre, Division of Developmental Biology & Medicine, School of Medical Sciences, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, M13 9WL, UK
| | - Paul Brownbill
- Maternal and Fetal Health Research Centre, Division of Developmental Biology & Medicine, School of Medical Sciences, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, M13 9WL, UK.
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Mammatas LH, Zandvliet AS, Rovithi M, Honeywell RJ, Swart EL, Peters GJ, Menke-van der Houven van Oordt CW, Verheul HMW. Sorafenib administered using a high-dose, pulsatile regimen in patients with advanced solid malignancies: a phase I exposure escalation study. Cancer Chemother Pharmacol 2020; 85:931-40. [PMID: 32274565 DOI: 10.1007/s00280-020-04065-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 03/24/2020] [Indexed: 01/07/2023]
Abstract
Background (Pre)clinical evidence is accumulating that intermittent exposure to increased doses of protein kinase inhibitors may improve their treatment benefit. In this phase I trial, the safety of high-dose, pulsatile sorafenib was studied. Patients and methods High-dose sorafenib was administered once weekly in exposure escalation cohorts according to a 3 + 3 design. Drug monitoring was performed in weeks 1–3 and doses were adjusted to achieve a predefined target plasma area under the curve (AUC)(0–12 h). The effect of low gastric pH on improving sorafenib exposure was investigated by intake of the acidic beverage cola. Results Seventeen patients with advanced malignancies without standard treatment options were included. Once weekly, high-dose sorafenib exposure was escalated up to a target AUC(0–12 h) of 125–150 mg/L/h, achieving a twofold higher Cmax compared to standard continuous dosing. Dose-limiting toxicity was observed in three patients: grade 3 duodenal perforation (2800 mg sorafenib), grade 5 multiorgan failure (2800 mg sorafenib) and grade 5 biliary tract perforation (3600 mg sorafenib). The mean difference between observed and target AUC(0–12 h) was 45% (SD ± 56%) in week 1 using a fixed starting dose of sorafenib compared to 2% (SD ± 32%) in week 3 as a result of drug monitoring (P = 0.06). Dissolving sorafenib in cola, instead of water, did not improve sorafenib exposure. Clinical benefit with stable disease as the best response was observed in two patients. Conclusion Treatment with high-dose, once weekly sorafenib administration resulted in dose-limiting toxicity precluding dose escalation above the exposure cohort of 125–150 mg/L/h. Drug monitoring was a successful strategy to pursue a target exposure. Electronic supplementary material The online version of this article (10.1007/s00280-020-04065-5) contains supplementary material, which is available to authorized users.
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Raman K, Sheriff EA, Jamesraj J, Kumar R. An Aortic Root Abscess Presenting as a Suprasternal Pulsatile Mass. Korean J Thorac Cardiovasc Surg 2019; 52:178-181. [PMID: 31236380 PMCID: PMC6559191 DOI: 10.5090/kjtcs.2019.52.3.178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 03/03/2019] [Accepted: 03/07/2019] [Indexed: 11/16/2022]
Abstract
Prosthetic valve endocarditis with aortic root abscess is a serious condition requiring urgent surgical intervention. We present a case caused by an infected Bentall mechanical valve conduit after cardiac surgery in a patient who was referred for a suprasternal pulsatile mass. The patient also had 1 episode of sentinel haemorrhage.
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Affiliation(s)
- Karthik Raman
- Department of Cardiac Surgery, The Madras Medical Mission, Chennai, India
| | - Ejaz Ahmed Sheriff
- Department of Cardiac Surgery, The Madras Medical Mission, Chennai, India
| | - Jacob Jamesraj
- Department of Cardiac Surgery, The Madras Medical Mission, Chennai, India
| | - Ram Kumar
- Department of Cardiology, The Madras Medical Mission, Chennai, India
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Kretzschmar D, Schulze PC, Ferrari MW. Concept, Evaluation, and Future Perspectives of PERKAT® RV-A Novel Right Ventricular Assist Device. J Cardiovasc Transl Res 2018; 12:150-154. [PMID: 30267328 DOI: 10.1007/s12265-018-9834-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 09/10/2018] [Indexed: 11/28/2022]
Abstract
Right heart failure (RHF) is a life-threatening condition. Mechanical right heart support offers an option for critically ill patients. The PERKAT® RV device is designed for percutaneous implantation in acute RHF. It consists of a nitinol chamber covered by foils containing inflow valves. An outlet tube is attached to its distal tip. Using an 18F sheath, it is implanted in the inferior vena cava while the tube bypasses the right heart with its tip in the pulmonary trunk. Then, an IABP balloon is inserted in the pump chamber. Balloon deflation generates blood inflow into the chamber; during inflation, blood is pumped into the pulmonary arteries. The device is capable of achieving flow rates of up to 3.5 l/min under in vitro conditions. In vivo, we were able to increase cardiac output by 59% in a sheep model of acute pulmonary embolism. Based on this, our further research will focus on first-in-human implants.
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Affiliation(s)
- Daniel Kretzschmar
- Department of Internal Medicine I, University Hospital Jena, Friedrich-Schiller-University Jena, Am Klinikum 1, 07740, Jena, Germany.
| | - P Christian Schulze
- Department of Internal Medicine I, University Hospital Jena, Friedrich-Schiller-University Jena, Am Klinikum 1, 07740, Jena, Germany
| | - Markus W Ferrari
- HSK, Department of Internal Medicine I, Helios-Clinics, Wiesbaden, Germany
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Kreibich M, Trummer G, Beyersdorf F, Scherer C, Förster K, Taunyane I, Benk C. Improved Outcome in an Animal Model of Prolonged Cardiac Arrest Through Pulsatile High Pressure Controlled Automated Reperfusion of the Whole Body. Artif Organs 2018; 42:992-1000. [PMID: 30015357 DOI: 10.1111/aor.13147] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/09/2018] [Accepted: 02/23/2018] [Indexed: 12/22/2022]
Abstract
The reperfusion period after extracorporeal cardiopulmonary resuscitation has been recognized as a key player in improving the outcome after cardiac arrest (CA). Our aim was to evaluate the effects of high mean arterial pressure (MAP) and pulsatile flow during controlled automated reperfusion of the whole body. Following 20 min of normothermic CA, high MAP, and pulsatile blood flow (pulsatile group, n = 10) or low MAP and nonpulsatile flow (nonpulsatile group, n = 6) controlled automated reperfusion of the whole body was commenced through the femoral vessels of German landrace pigs for 60 min. Afterwards, animals were observed for eight days. Blood samples were analyzed throughout the experiment and a species-specific neurologic disability score (NDS) was used for neurologic evaluation. In the pulsatile group, nine animals finished the study protocol, while no animal survived postoperative day four in the nonpulsatile group. NDS were significantly better at any given time in the pulsatile group and reached overall satisfactory outcome values. In addition, blood analyses revealed lower levels of lactate in the pulsatile group compared to the nonpulsatile group. This study demonstrates superior survival and neurologic outcome when using pulsatile high pressure automated reperfusion following 20 min of normothermic CA compared to nonpulsatile flow and low MAP. This study strongly supports regulating the reperfusion period after prolonged periods of CA.
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Affiliation(s)
- Maximilian Kreibich
- Faculty of Medicine, Department of Cardiovascular Surgery, Heart Centre Freiburg University, University of Freiburg, Freiburg, Germany
| | - Georg Trummer
- Faculty of Medicine, Department of Cardiovascular Surgery, Heart Centre Freiburg University, University of Freiburg, Freiburg, Germany
| | - Friedhelm Beyersdorf
- Faculty of Medicine, Department of Cardiovascular Surgery, Heart Centre Freiburg University, University of Freiburg, Freiburg, Germany
| | - Christian Scherer
- Faculty of Medicine, Department of Cardiovascular Surgery, Heart Centre Freiburg University, University of Freiburg, Freiburg, Germany
| | - Katharina Förster
- Faculty of Medicine, Department of Cardiovascular Surgery, Heart Centre Freiburg University, University of Freiburg, Freiburg, Germany
| | - Itumeleng Taunyane
- Faculty of Medicine, Department of Cardiovascular Surgery, Heart Centre Freiburg University, University of Freiburg, Freiburg, Germany
| | - Christoph Benk
- Faculty of Medicine, Department of Cardiovascular Surgery, Heart Centre Freiburg University, University of Freiburg, Freiburg, Germany
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Pandit V, Kumar A, Ashawat MS, Verma CP, Kumar P. Recent Advancement and Technological Aspects of Pulsatile Drug Delivery System - A Laconic Review. Curr Drug Targets 2018; 18:1191-1203. [PMID: 26853323 DOI: 10.2174/1389450117666160208144343] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 01/30/2016] [Accepted: 02/01/2016] [Indexed: 11/22/2022]
Abstract
BACKGROUND Pulsatile drug delivery system (PDDS) shows potential significance in the field of drug delivery to release the maximum amount of drug at a definite site and at specific time. PDDS are mainly time controlled delivery devices having a definite pause period for drug release, which is not affected by acidity, alkalinity, motility and enzymes present in the gastrointestinal tract. Pulsatile medication possess the potential to deliver the drugs in the therapy of diseases where drug dose is essential during sleep, drugs having greater first pass metabolism and absorption at precise location in digestive tract. OBJECTIVE The review article, discuss the general concepts, marketed formulations and patents or any other recent advancement in pulsatile release technology. It also highlights on diseases requiring therapy by pulsatile release, various researches on herbal pulsatile formulations and quality control aspects of PDDS. CONCLUSION Pulsatile medication possess the potential to deliver the drugs in the therapy of diseases where drug dose is essential during sleep, drugs having greater first pass metabolism and absorption at precise location in digestive tract.
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Affiliation(s)
- Vinay Pandit
- Department of Pharmaceutics, Laureate Institute of Pharmacy, Kathog, Kangra (H.P) - 177101, India
| | - Ajay Kumar
- Department of Pharmaceutics, Laureate Institute of Pharmacy, Kathog, Kangra (H.P) - 177101, India
| | - Mahendra S Ashawat
- Department of Pharmaceutics, Laureate Institute of Pharmacy, Kathog, Kangra (H.P) - 177101, India
| | - Chander P Verma
- Department of Pharmaceutics, Laureate Institute of Pharmacy, Kathog, Kangra (H.P) - 177101, India
| | - Pravin Kumar
- Department of Pharmaceutics, Laureate Institute of Pharmacy, Kathog, Kangra (H.P) - 177101, India
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Abstract
Arterial thrombus formation is directly related to the mechanical shear experienced by platelets within flow. High shear strain rates (SSRs) and large shear gradients cause platelet activation, aggregation and production of thrombus. This study, for the first time, investigates the influence of pulsatile flow on local haemodynamics within sutured microarterial anastomoses. We measured physiological arterial waveform velocities experimentally using Doppler ultrasound velocimetry, and a representative example was applied to a realistic sutured microarterial geometry. Computational geometries were created using measurements taken from sutured chicken femoral arteries. Arterial SSRs were predicted using computational fluid dynamics (CFD) software, to indicate the potential for platelet activation, deposition and thrombus formation. Predictions of steady and sinusoidal inputs were compared to analyse whether the addition of physiological pulse characteristics affects local intravascular flow characteristics. Simulations were designed to evaluate flow in pristine and hand-sutured microarterial anastomoses, each with a steady-state and sinusoidal pulse component. The presence of sutures increased SSRmax in the anastomotic region by factors of 2.1 and 2.3 in steady-state and pulsatile flows respectively, when compared to a pristine vessel. SSR values seen in these simulations are analogous to the presence of moderate arterial stenosis. Steady-state simulations, driven by a constant inflow velocity equal to the peak systolic velocity (PSV) of the measured pulsatile flow, underestimated SSRs by ∼ 9% in pristine, and ∼ 19% in sutured vessels compared with a realistic pulse. Sinusoidal flows, with equivalent frequency and amplitude to a measured arterial waveform, represent a slight improvement on steady-state simulations, but still SSRs are underestimated by 1-2%. We recommend using a measured arterial waveform, of the form presented here, for simulating pulsatile flows in vessels of this nature. Under realistic pulsatile flow, shear gradients across microvascular sutures are high, of the order ∼ 7.9 × 106 m-1 s-1, which may also be associated with activation of platelets and formation of aggregates.
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Affiliation(s)
- R A J Wain
- School of Mathematics, University of Birmingham, B15 2TT, UK; Institute of Translational Medicine, University of Birmingham, B15 2TT, UK; School of Medicine and Dentistry, University of Central Lancashire, Preston PR1 2HE, UK; Computational Mechanics Research Group, School of Engineering, University of Central Lancashire, Preston PR1 2HE, UK.
| | - D J Smith
- School of Mathematics, University of Birmingham, B15 2TT, UK; Institute for Metabolism and Systems Research, University of Birmingham, B15 2TT, UK
| | - D R Hammond
- School of Medicine and Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
| | - J P M Whitty
- Computational Mechanics Research Group, School of Engineering, University of Central Lancashire, Preston PR1 2HE, UK
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12
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Nassar MS, Hasan A, Chila T, Schueler S, Pergolizzi C, Reinhardt Z, Lord S, De Rita F, Ferguson L, Smith J, Haynes S, O'Sullivan J, Murtuza B. Comparison of paracorporeal and continuous flow ventricular assist devices in children: preliminary results. Eur J Cardiothorac Surg 2017; 51:709-714. [PMID: 28329112 DOI: 10.1093/ejcts/ezx006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 12/11/2016] [Indexed: 11/12/2022] Open
Abstract
Objectives With the scarcity of organs, a durable, reliable ventricular assist device (VAD) is required. The Berlin Heart EXCOR ® (BH) remains the most established VAD in the paediatric population. Implantable continuous flow (CF) VADs have been introduced to the paediatric field with encouraging early results. In this study, we compared the results of a newly introduced CF VAD (HeartWare VAD [HVAD] ® ) to results in a matched group of BH recipients. Methods The study included patients aged <16 years who received mechanical left VAD (LVAD) support between December 2005 and January 2016. The preimplant characteristics and postimplant outcomes of patients who received the HVAD were compared with those of a matched group who received the BH. Patients with congenital heart disease were excluded. Results Thirty patients were included in the study: 13 had received the HVAD and were matched with 17 patients who had received the BH LVAD. The only difference in preimplant characteristics was the need for higher inotropic support in the BH group. There was no difference in the need for right ventricular (RV) support (58.8% for BH vs 53.8% for HVAD, P = 1.00) or in the incidence of cerebrovascular accidents (12.5% vs 7.7%, respectively, P = 1.00), though the BH group showed prolonged mechanical ventilation (31.3% vs 0%, P = 0.047). There were no deaths while on VAD support in either group. Patients with the HVAD showed a bimodal distribution for the primary end point (transplant/explant): All HVAD recipients who also required early RV support reached this end point within 30 days of receiving the implant. Conclusions Our early experience with the CF intracorporeal LVAD system (HVAD) indicates outcomes comparable to those with the well-established pulsatile flow paracorporeal LVAD (BH). The theoretical durability of the CF device, which might also allow for the possibility of hospital discharge and better quality of life, is yet to be proven.
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Affiliation(s)
- Mohamed S Nassar
- Department of Paediatric Cardiac Surgery, Anaesthesia & Intensive Care, Freeman Hospital, Newcastle Upon Tyne, UK.,Department of Cardiopulmonary Transplantation, Freeman Hospital, Newcastle Upon Tyne, UK.,Department of Cardiothoracic Surgery, Alexandria University, Alexandria, Egypt
| | - Asif Hasan
- Department of Paediatric Cardiac Surgery, Anaesthesia & Intensive Care, Freeman Hospital, Newcastle Upon Tyne, UK.,Department of Cardiopulmonary Transplantation, Freeman Hospital, Newcastle Upon Tyne, UK
| | - Teresa Chila
- Department of Paediatric Cardiac Surgery, Anaesthesia & Intensive Care, Freeman Hospital, Newcastle Upon Tyne, UK
| | - Stephan Schueler
- Department of Cardiopulmonary Transplantation, Freeman Hospital, Newcastle Upon Tyne, UK
| | - Carola Pergolizzi
- Department of Paediatric Cardiac Surgery, Anaesthesia & Intensive Care, Freeman Hospital, Newcastle Upon Tyne, UK
| | - Zdenka Reinhardt
- Department of Paediatric Cardiac Surgery, Anaesthesia & Intensive Care, Freeman Hospital, Newcastle Upon Tyne, UK.,Department of Cardiopulmonary Transplantation, Freeman Hospital, Newcastle Upon Tyne, UK
| | - Stephen Lord
- Department of Paediatric Cardiac Surgery, Anaesthesia & Intensive Care, Freeman Hospital, Newcastle Upon Tyne, UK
| | - Fabrizio De Rita
- Department of Paediatric Cardiac Surgery, Anaesthesia & Intensive Care, Freeman Hospital, Newcastle Upon Tyne, UK.,Department of Cardiopulmonary Transplantation, Freeman Hospital, Newcastle Upon Tyne, UK
| | - Lee Ferguson
- Department of Paediatric Cardiac Surgery, Anaesthesia & Intensive Care, Freeman Hospital, Newcastle Upon Tyne, UK
| | - Jon Smith
- Department of Paediatric Cardiac Surgery, Anaesthesia & Intensive Care, Freeman Hospital, Newcastle Upon Tyne, UK
| | - Simon Haynes
- Department of Paediatric Cardiac Surgery, Anaesthesia & Intensive Care, Freeman Hospital, Newcastle Upon Tyne, UK
| | - John O'Sullivan
- Department of Paediatric Cardiac Surgery, Anaesthesia & Intensive Care, Freeman Hospital, Newcastle Upon Tyne, UK
| | - Bari Murtuza
- Department of Paediatric Cardiac Surgery, Anaesthesia & Intensive Care, Freeman Hospital, Newcastle Upon Tyne, UK.,Department of Cardiopulmonary Transplantation, Freeman Hospital, Newcastle Upon Tyne, UK
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13
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Rovithi M, de Haas RR, Honeywell RJ, Poel D, Peters GJ, Griffioen AW, Verheul HMW. Alternative scheduling of pulsatile, high dose sunitinib efficiently suppresses tumor growth. J Exp Clin Cancer Res 2016; 35:138. [PMID: 27604186 PMCID: PMC5013589 DOI: 10.1186/s13046-016-0411-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/25/2016] [Indexed: 01/11/2023]
Abstract
Background Increased exposure to multitargeted kinase inhibitor sunitinib is associated with improved outcome, emphasizing the importance of maintaining adequate dosing and drug levels. The currently approved schedule (50 mg daily, four weeks on, two weeks off) precludes further dose-intensification. Recent data suggest that sunitinib, although initially developed as an antiangiogenic agent, has direct antitumor activity. Methods In this study, we tested whether a chemotherapy-like schedule of pulsatile high dose sunitinib would result in improved antitumor activity. Results In vitro, a single exposure to 20 μM sunitinib for 6-9 h resulted in complete inhibition of tumor cell growth and cell death conveyed through activation of caspases and autophagy upregulation. Notably, repeated exposure of tumor cells to pulses of high concentrations of sunitinib did not induce resistance. In vivo, once-weekly treatment with high dose sunitinib of tumors growing on the chorioallantoic membrane (CAM) of the chicken embryo significantly impaired tumor growth by 57 % compared to vehicle, outperforming the daily, standard scheduling. Conclusions These results prompted the initiation of a phase I clinical trial, where intermittent, high dose sunitinib is being investigated in patients with advanced solid tumors (registration number and date: NCT02058901, 30 September 2013, respectively). The trial is actively recruiting patients and promising preliminary indications of antitumor activity have been observed.
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Affiliation(s)
- Maria Rovithi
- Department of Medical Oncology, VU University Medical Center, Amsterdam, The Netherlands
| | - Richard R de Haas
- Department of Medical Oncology, VU University Medical Center, Amsterdam, The Netherlands
| | - Richard J Honeywell
- Department of Medical Oncology, VU University Medical Center, Amsterdam, The Netherlands
| | - Dennis Poel
- Department of Medical Oncology, VU University Medical Center, Amsterdam, The Netherlands
| | - Godefridus J Peters
- Department of Medical Oncology, VU University Medical Center, Amsterdam, The Netherlands
| | - Arjan W Griffioen
- Department of Medical Oncology, VU University Medical Center, Amsterdam, The Netherlands
| | - Henk M W Verheul
- Department of Medical Oncology, VU University Medical Center, Amsterdam, The Netherlands.
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14
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Plachta DTT, Zentner J, Aguirre D, Cota O, Stieglitz T, Gierthmuehlen M. Effect of Cardiac-Cycle-Synchronized Selective Vagal Stimulation on Heart Rate and Blood Pressure in Rats. Adv Ther 2016; 33:1246-61. [PMID: 27220533 DOI: 10.1007/s12325-016-0348-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Activation of the baroreflex system through the selective vagal nerve stimulation (sVNS) may become a treatment option for therapy-resistant hypertension, which is a frequently observed problem in the antihypertensive therapy. In previous studies, we used continuous sVNS to lower blood pressure (BP) without major side effects in a rat model. As continuous stimulation is energy consuming and sVNS could be implemented in an antihypertensive stimulator, it was the aim of this study to investigate the efficacy of pulsatile, cardiac-cycle-synchronized sVNS (cssVNS) on the reduction of BP. METHODS A multichannel cuff electrode was wrapped around the left vagal nerve in six male Wistar rats under Isoflurane anesthesia. BP was recorded in the left carotid artery. An electrocardiogram (ECG) was obtained via subcutaneous needle electrodes. The aortic depressor nerve fibers in the vagal nerve bundle were selectively stimulated with 18 parameter settings within a window of 15-30 ms after the R-peak in the ECG. The stimulation paradigm included every heartbeat, every second heart beat, and every third heart beat. BP and heart rate were initially recorded over 10 min. RESULTS Using cssVNS, BP could be significantly reduced over 30 min and maintained at this level. While the highest BP reduction was seen during cssVNS at every heartbeat with minimal bradycardia, less-yet significant-BP reduction was seen during cssVNS at every second or third heartbeat without causing detectable bradycardia. CONCLUSION cssVNS can chronically reduce BP in rats avoiding measurable bradycardic side effects. This energy-efficient technique might allow the implementation of sVNS using an implantable device to permanently lower BP in patients. FUNDING The study was funded by Bundesministerium fur Bildung und Forschung/German Federal Ministry of Education and Research among the call "Individualisierte Medizintechnik" under the grant number FKZ 13GW0120B.
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Affiliation(s)
- Dennis T T Plachta
- Department of Neurosurgery, Medical Center, Faculty of Medicine, University of Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany
| | - Josef Zentner
- Department of Neurosurgery, Medical Center, Faculty of Medicine, University of Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany
| | - Debora Aguirre
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering-IMTEK, University of Freiburg, Georges-Koehler-Allee 106, 79110, Freiburg, Germany
| | - Oscar Cota
- Neuroloop GmbH, Engesserstr. 4, 79108, Freiburg, Germany
| | - Thomas Stieglitz
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering-IMTEK, University of Freiburg, Georges-Koehler-Allee 106, 79110, Freiburg, Germany
| | - Mortimer Gierthmuehlen
- Department of Neurosurgery, Medical Center, Faculty of Medicine, University of Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany.
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15
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Plummer MP, Kar P, Cousins CE, Lange K, Chapman MJ, Nauck MA, Horowitz M, Meier JJ, Deane AM. The insulinotropic effect of pulsatile compared with continuous intravenous delivery of GLP-1. Diabetologia 2016; 59:966-9. [PMID: 26831299 DOI: 10.1007/s00125-016-3878-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 01/06/2016] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS In healthy individuals, both insulin and glucagon-like peptide 1 (GLP-1) are secreted in a pulsatile fashion. Insulin has greater glucose-lowering properties when administered in pulses compared with a constant i.v. infusion. The primary aim of this randomised double-dummy cross-over study was to compare the insulinotropic response to pulsatile and continuous i.v. infusions of equivalent doses of GLP-1. METHODS Twelve healthy participants aged 18-35 years were randomised to three different treatments on separate days: a continuous infusion day (GLP-1 at 0.6 pmol kg(-1) min(-1) [1 ml/min] and a 1 ml placebo bolus every 6 min); a pulsatile infusion day (placebo at 1 ml/min and a 3.6 pmol/kg GLP-1 bolus every 6 min); and a placebo day (placebo at 1 ml/min and a 1 ml placebo bolus every 6 min). Between 45 and 120 min, a hyperglycaemic clamp was used to maintain blood glucose at 9 mmol/l. Venous blood glucose and plasma insulin concentrations were measured every 5 min from 0 to 45 min and every 1 min from 45 to 120 min; plasma glucagon was measured every 15 min. The order of treatment was randomised by the Pharmacy Department and both study investigators and participants were blinded to the treatment arm. The dextrose requirement and glucagon data were analysed using repeated measures ANOVA and insulin data were analysed with a linear mixed effects maximum likelihood model. RESULTS Continuous and pulsatile infusions of GLP-1 increased the dextrose requirement by ~threefold (p < 0.001) and increased insulin secretion by ~ninefold (p < 0.001). There was no difference in the effect of both treatments. Although hyperglycaemia reduced plasma glucagon concentrations, there was no difference between the treatment days. CONCLUSIONS/INTERPRETATION In healthy individuals, pulsatile and continuous administration of i.v. GLP-1 appears to have comparable insulinotropic effects. TRIAL REGISTRATION ACTRN12612001040853 FUNDING: This study was supported by the National Health and Medical Research Council (NHMRC) of Australia.
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Affiliation(s)
- Mark P Plummer
- Discipline of Acute Care Medicine, University of Adelaide, Adelaide, SA, Australia.
- Intensive Care Research Unit, Level 4 Emergency Block, Royal Adelaide Hospital, North Terrace, Adelaide, SA, 5000, Australia.
| | - Palash Kar
- Discipline of Acute Care Medicine, University of Adelaide, Adelaide, SA, Australia
- Intensive Care Research Unit, Level 4 Emergency Block, Royal Adelaide Hospital, North Terrace, Adelaide, SA, 5000, Australia
| | - Caroline E Cousins
- Intensive Care Research Unit, Level 4 Emergency Block, Royal Adelaide Hospital, North Terrace, Adelaide, SA, 5000, Australia
| | - Kylie Lange
- Discipline of Medicine, University of Adelaide, Adelaide, SA, Australia
| | - Marianne J Chapman
- Discipline of Acute Care Medicine, University of Adelaide, Adelaide, SA, Australia
- Intensive Care Research Unit, Level 4 Emergency Block, Royal Adelaide Hospital, North Terrace, Adelaide, SA, 5000, Australia
| | - Michael A Nauck
- Division of Diabetes and GI Endocrinology, University Hospital St Josef-Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Michael Horowitz
- Discipline of Medicine, University of Adelaide, Adelaide, SA, Australia
| | - Juris J Meier
- Division of Diabetes and GI Endocrinology, University Hospital St Josef-Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Adam M Deane
- Discipline of Acute Care Medicine, University of Adelaide, Adelaide, SA, Australia
- Intensive Care Research Unit, Level 4 Emergency Block, Royal Adelaide Hospital, North Terrace, Adelaide, SA, 5000, Australia
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Yurimoto T, Hara S, Isoyama T, Saito I, Ono T, Abe Y. Viscosity-adjusted estimation of pressure head and pump flow with quasi- pulsatile modulation of rotary blood pump for a total artificial heart. J Artif Organs 2016; 19:219-25. [PMID: 27022734 DOI: 10.1007/s10047-016-0898-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 03/16/2016] [Indexed: 10/22/2022]
Abstract
Estimation of pressure and flow has been an important subject for developing implantable artificial hearts. To realize real-time viscosity-adjusted estimation of pressure head and pump flow for a total artificial heart, we propose the table estimation method with quasi-pulsatile modulation of rotary blood pump in which systolic high flow and diastolic low flow phased are generated. The table estimation method utilizes three kinds of tables: viscosity, pressure and flow tables. Viscosity is estimated from the characteristic that differential value in motor speed between systolic and diastolic phases varies depending on viscosity. Potential of this estimation method was investigated using mock circulation system. Glycerin solution diluted with salty water was used to adjust viscosity of fluid. In verification of this method using continuous flow data, fairly good estimation could be possible when differential pulse width modulation (PWM) value of the motor between systolic and diastolic phases was high. In estimation under quasi-pulsatile condition, inertia correction was provided and fairly good estimation was possible when the differential PWM value was high, which was not different from the verification results using continuous flow data. In the experiment of real-time estimation applying moving average method to the estimated viscosity, fair estimation could be possible when the differential PWM value was high, showing that real-time viscosity-adjusted estimation of pressure head and pump flow would be possible with this novel estimation method when the differential PWM value would be set high.
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17
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Sachdeva V, Haque N, Pathengay A, Kekunnaya R. Pulsatile enophthalmos, severe esotropia, kinked optic nerve and visual loss in neurofibromatosis type-1. Oman J Ophthalmol 2016; 8:208-10. [PMID: 26903735 PMCID: PMC4738674 DOI: 10.4103/0974-620x.169894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neurofibromatosis Type I if associated with aplasia of greater wing of sphenoid may be associated with a pulsatile exophthalmos. However, very rarely it may be associated with a pulsatile enophthalmos. This clinical image describes a rare presentation with pulsatile enophthalmos, esotropia and kinking of the optic nerve due to neurofibomatosis type I.
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Affiliation(s)
- Virender Sachdeva
- Department of Pediatric Ophthalmology, Strasbimsus and Neuro-ophhtalmology, Nimmagada Prasad Children's Eye care Centre, LVPEI-GMRV Campus, LVPEI, KAR Campus, Hyderabad, India
| | - Nazmul Haque
- Department of Pediatric Ophthalmology, Strabismus and Neuro-ophtalmology, Jasti V Ramanamma Children's Eye Care Centre, LVPEI, KAR Campus, Hyderabad, India
| | - Avinash Pathengay
- Department of Retina and Vitreous Services, LVPEI, GMRV Campus, Visakhapatnam, India
| | - Ramesh Kekunnaya
- Department of Pediatric Ophthalmology, Strabismus and Neuro-ophtalmology, Jasti V Ramanamma Children's Eye Care Centre, LVPEI, KAR Campus, Hyderabad, India
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Mohammed H, Briggs M, Phillips J. Pulsatile tinnitus as the presenting symptom in a patient with posterior reversible encephalopathy syndrome. Eur Arch Otorhinolaryngol 2016; 273:2847-51. [PMID: 26661070 DOI: 10.1007/s00405-015-3847-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 11/27/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVES We present a case of posterior reversible encephalopathy syndrome (PRES) presenting with pulsatile tinnitus. We highlight the significance of a detailed neurological and cardiovascular assessment including the measurement of blood pressure in patients presenting with pulsatile tinnitus. METHOD Case presentation and literature review. RESULTS One patient with undiagnosed PRES, who presented to our ear, nose and throat surgery department with pulsatile tinnitus is discussed. Symptoms, signs, investigations and treatments are presented. A literature review is also included. CONCLUSION Pulsatile tinnitus can be the presenting symptom of neurovascular disorders, some of which might have serious sequelae if not treated promptly. Detailed neurological and cardiovascular history is recommended in addition to radiological investigations in patients presenting with pulsatile tinnitus.
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Itoh H, Ichiba S, Ujike Y, Douguchi T, Obata H, Inamori S, Iwasaki T, Kasahara S, Sano S, Ündar A. Effect of the Pulsatile Extracorporeal Membrane Oxygenation on Hemodynamic Energy and Systemic Microcirculation in a Piglet Model of Acute Cardiac Failure. Artif Organs 2015; 40:19-26. [PMID: 26526784 DOI: 10.1111/aor.12588] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The objective of this study was to compare the effects of pulsatile and nonpulsatile extracorporeal membrane oxygenation (ECMO) on hemodynamic energy and systemic microcirculation in an acute cardiac failure model in piglets. Fourteen piglets with a mean body weight of 6.08 ± 0.86 kg were divided into pulsatile (N = 7) and nonpulsatile (N = 7) ECMO groups. The experimental ECMO circuit consisted of a centrifugal pump, a membrane oxygenator, and a pneumatic pulsatile flow generator system developed in-house. Nonpulsatile ECMO was initiated at a flow rate of 140 mL/kg/min for the first 30 min with normal heart beating, with rectal temperature maintained at 36°C. Ventricular fibrillation was then induced with a 3.5-V alternating current to generate a cardiac dysfunction model. Using this model, we collected the data on pulsatile and nonpulsatile groups. The piglets were weaned off ECMO at the end of the experiment (180 min after ECMO was initiated). The animals did not receive blood transfusions, inotropic drugs, or vasoactive drugs. Blood samples were collected to measure hemoglobin, methemoglobin, blood gases, electrolytes, and lactic acid levels. Hemodynamic energy was calculated using the Shepard's energy equivalent pressure. Near-infrared spectroscopy was used to monitor brain and kidney perfusion. The pulsatile ECMO group had a higher atrial pressure (systolic and mean), and significantly higher regional saturation at the brain level, than the nonpulsatile group (for both, P < 0.05). Additionally, the pulsatile ECMO group had higher methemoglobin levels within the normal range than the nonpulsatile group. Our study demonstrated that pulsatile ECMO produces significantly higher hemodynamic energy and improves systemic microcirculation, compared with nonpulsatile ECMO in acute cardiac failure.
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Affiliation(s)
- Hideshi Itoh
- Department of Medical Engineering, Faculty of Health Sciences, Junshin Gakuen University, Fukuoka, Japan.,Departments of, Emergency and Critical Care Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Shingo Ichiba
- Community and Emergency Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Yoshihito Ujike
- Departments of, Emergency and Critical Care Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Takuma Douguchi
- Department of, Cardiovascular Surgery, Okayama University Hospital, Okayama, Japan
| | - Hideaki Obata
- Biomedical Engineering, Okayama University of Science, Okayama, Japan
| | - Syuji Inamori
- Department of Medical Engineering, Faculty of Health Sciences, Junshin Gakuen University, Fukuoka, Japan
| | - Tatsuo Iwasaki
- Anesthesiology, Okayama University Hospital, Okayama, Japan
| | - Shingo Kasahara
- Department of, Cardiovascular Surgery, Okayama University Hospital, Okayama, Japan
| | - Shunji Sano
- Department of, Cardiovascular Surgery, Okayama University Hospital, Okayama, Japan
| | - Akif Ündar
- Departments of Pediatrics, Surgery, and Bioengineering, Penn State Hershey Pediatric Cardiovascular Research Center, Hershey, PA, USA
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Jagdale SC, Suryawanshi VM, Pandya SV, Kuchekar BS, Chabukswar AR. Development of press-coated, floating- pulsatile drug delivery of lisinopril. Sci Pharm 2014; 82:423-40. [PMID: 24959410 PMCID: PMC4065132 DOI: 10.3797/scipharm.1301-27] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 04/14/2014] [Indexed: 01/09/2023] Open
Abstract
Lisinopril is an angiotensin-converting enzyme (ACE) inhibitor, primarily used for the treatment of hypertension, congestive heart failure, and heart attack. It belongs to BCS class III having a half-life of 12 hrs and 25% bioavailability. The purpose of the present work was to develop a press-coated, floating-pulsatile drug delivery system. The core tablet was formulated using the super-disintegrants crosprovidone and croscarmellose sodium. A press-coated tablet (barrier layer) contained the polymer carrageenan, xanthan gum, HPMC K4M, and HPMC K15M. The buoyant layer was optimized with HPMC K100M, sodium bicarbonate, and citric acid. The tablets were evaluated for physical characteristics, floating lag time, swelling index, FTIR, DSC, and in vitro and in vivo behavior. The 5% superdisintgrant showed good results. The FTIR and DSC study predicted no chemical interactions between the drug and excipients. The formulation containing xanthan gum showed drug retaining abilities, but failed to float. The tablet containing HPMC K15M showed a high swelling index. The lag time for the tablet coated with 200 mg carrageenan was 3±0.1 hrs with 99.99±1.5% drug release; with 140 mg HPMC K4M, the lag time was 3±0.1 hrs with 99.71±1.2% drug release; and with 120 mg HPMC K15M, the lag time was 3±0.2 hrs with 99.98±1.7% drug release. The release mechanism of the tablet followed the Korsmeyer-Peppas equation and a first-order release pattern. Floating and lag time behavior have shown good in vitro and in vivo correlations.
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Affiliation(s)
- Swati C Jagdale
- Department of Pharmaceutics, MAEER's Maharashtra Institute of Pharmacy, Kothrud, Pune, 411 038, Maharashtra, India
| | - Vishnu M Suryawanshi
- Department of Pharmaceutics, MAEER's Maharashtra Institute of Pharmacy, Kothrud, Pune, 411 038, Maharashtra, India
| | - Sudhir V Pandya
- Quality Assurance, Nulife Pharmaceuticals, Pimpri, 411 018 Pune, Maharashtra, India
| | - Bhanudas S Kuchekar
- Department of Pharmaceutical Chemistry, MAEER's Maharashtra Institute of Pharmacy, Kothrud, Pune, 411 038, Maharashtra, India
| | - Aniruddha R Chabukswar
- Department of Pharmaceutical Chemistry, MAEER's Maharashtra Institute of Pharmacy, Kothrud, Pune, 411 038, Maharashtra, India
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Jagdale SC, Sali MS, Barhate AL, Kuchekar BS, Chabukswar AR. Formulation, development, and evaluation of floating pulsatile drug delivery system of atenolol. PDA J Pharm Sci Technol 2013; 67:214-228. [PMID: 23752749 DOI: 10.5731/pdajpst.2013.00916] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
UNLABELLED The objective of this work was to develop and evaluate a floating-pulsatile drug delivery of atenolol. The floating-pulsatile concept was applied to increase the gastric residence of the dosage form by having lag phase followed by a burst release. The system was generated which consisted of three different parts: a core tablet, containing the active ingredient; an erodible outer shell; and a top cover buoyant layer. The dry, coated tablet consists in a drug-containing core, coated by a hydrophilic erodible polymer responsible for a lag phase in the onset of pulsatile release. The buoyant layer, prepared with hydroxypropyl methylcellulose (HPMC) K100 M, citric acid, and sodium bicarbonate, provides buoyancy to increase the retention of the oral dosage form in the stomach. The effect of the hydrophilic erodible polymer characteristics on the lag time and drug release was investigated. Developed formulations were evaluated for their physical properties in vitro release as well as in vivo behavior. The results showed that K3 (180 mg of HPMC K4 M) and K6 (290 mg of HPMC E15 LV) with a buoyant layer were the best formulation, with lag times of 5.2 ± 0.1 h and 4.1 ± 0.2 h, respectively. Floating time was controlled by the quantity and composition of the buoyant layer. In-vitro results point out the capability of the system with its prolonged residence of the tablets in the stomach and release of drug after a programmed lag time. This was confirmed by in vivo x-ray technique. LAY ABSTRACT The objective of the present work was to develop a floating-pulsatile oral drug delivery system of atenolol with addition of hydroxylpropyl methylcellulose (HPMC) K100 M, HPMC K4 M, and HPMC E15 LV in different ratios with citric acid and sodium bicarbonate as gas-forming agents. The system consist of three different parts: a core tablet, containing the active ingredient; a bottom layer that erodes; and a top cover floating layer. Atenolol, a β-blocker, is prescribed widely in diverse cardiovascular diseases, for example, hypertension, angina pectoris, arrhythmias, and myocardial infarction. Developed formulations were evaluated for their physical properties and vitro release as well as in vivo behavior. The results showed that K3 (180 mg HPMC K4 M) and K6 (290 mg of HPMC E15 LV) with a buoyant layer were the best formulations with the lag times of 5.2 ± 0.1 h and 4.1 ± 0.2 h, respectively, and were found to be the best choice for manufacturing tablets.
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Affiliation(s)
- Swati C Jagdale
- MAEER's Maharashtra Institute of Pharmacy, Kothrud, Pune, Maharashtra, India
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Masoumi N, Framanzad F, Zamanian B, Seddighi AS, Moosavi MH, Najarian S, Bastani D. 2D Computational Fluid Dynamic Modeling of Human Ventricle System Based on Fluid-Solid Interaction and Pulsatile Flow. Basic Clin Neurosci 2013; 4:64-75. [PMID: 25337330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Revised: 10/16/2012] [Accepted: 10/25/2012] [Indexed: 11/18/2022] Open
Abstract
Many diseases are related to cerebrospinal fluid (CSF) hydrodynamics. Therefore, understanding the hydrodynamics of CSF flow and intracranial pressure is helpful for obtaining deeper knowledge of pathological processes and providing better treatments. Furthermore, engineering a reliable computational method is promising approach for fabricating in vitro models which is essential for inventing generic medicines. A Fluid-Solid Interaction (FSI)model was constructed to simulate CSF flow. An important problem in modeling the CSF flow is the diastolic back flow. In this article, using both rigid and flexible conditions for ventricular system allowed us to evaluate the effect of surrounding brain tissue. Our model assumed an elastic wall for the ventricles and a pulsatile CSF input as its boundary conditions. A comparison of the results and the experimental data was done. The flexible model gave better results because it could reproduce the diastolic back flow mentioned in clinical research studies. The previous rigid models have ignored the brain parenchyma interaction with CSF and so had not reported the back flow during the diastolic time. In this computational fluid dynamic (CFD) analysis, the CSF pressure and flow velocity in different areas were concordant with the experimental data.
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