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Cunningham BW, Brooks DM, Rolle NP, Weiner DA, Wang W. An investigational time course study of titanium plasma spray on osseointegration of PEEK and titanium implants: an in vivo ovine model. Spine J 2024; 24:721-729. [PMID: 37875243 DOI: 10.1016/j.spinee.2023.10.005] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 09/13/2023] [Accepted: 10/14/2023] [Indexed: 10/26/2023]
Abstract
BACKGROUND CONTEXT Methods to improve osseointegration of orthopedic spinal implants remains a clinical challenge. Materials composed of poly-ether-ether-ketone (PEEK) and titanium are commonly used in orthopedic applications due to their inherent properties of biocompatibility. Titanium has a clinical reputation for durability and osseous affinity, and PEEK offers advantages of a modulus that approximates osseous structures and is radiolucent. The hypothesis for the current investigation was that a titanium plasma spray (TPS) coating may increase the rate and magnitude of circumferential and appositional trabecular osseointegration of PEEK and titanium implants versus uncoated controls. PURPOSE Using an in vivo ovine model, the current investigation compared titanium plasma-sprayed PEEK and titanium dowels versus nonplasma-sprayed dowels. Using a time course study of 6 and 12 weeks postoperatively, experimental assays to quantify osseointegration included micro-computed tomography (microCT), biomechanical testing, and histomorphometry. STUDY DESIGN/SETTING In-vivo ovine model. METHODS Twelve skeletally mature crossbred sheep were equally randomized into postoperative periods of 6 and 12 weeks. Four types of dowel implants-PEEK, titanium plasma-sprayed PEEK (TPS PEEK), titanium, and titanium plasma-sprayed titanium (TPS titanium) were implanted into cylindrical metaphyseal defects in the distal femurs and proximal humeri (one defect per limb, n=48 sites). Sixteen nonoperative specimens (eight femurs and eight humeri) served as zero time-point controls. Half of the specimens underwent destructive biomechanical pullout testing and the remaining half quantitative microCT to quantify circumferential bone volume within 1 mm and 2 mm of the implant surface and histomorphometry to compute direct trabecular apposition. RESULTS There were no intra- or perioperative complications. The TPS-coated implants demonstrated significantly higher peak loads at dowel pullout at 6 and 12 weeks compared with uncoated controls (p<.05). No differences were observed across dowel treatments at the zero time-point (p>.05). MicroCT results exhibited no significant differences in circumferential osseointegration between implants within 1 mm or 2 mm of the dowel surface (p>.05). Direct appositional osseointegration of trabecular bone based on histomorphometry was higher for TPS-coated groups, regardless of base material, compared with uncoated treatments at both time intervals (p<.05). CONCLUSIONS The current in vivo study demonstrated the biological and mechanical advantages of plasma spray coatings. TPS improved histological incorporation and peak force required for implant extraction. CLINICAL SIGNIFICANCE Plasma spray coatings may offer clinical benefit by improving biological fixation and osseointegration within the first 6 to 12 weeks postoperatively- the critical healing period for implant-based arthrodesis procedures.
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Affiliation(s)
- Bryan W Cunningham
- Musculoskeletal Research Center, Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, 201 E University Pkwy, Baltimore, MD 21218, USA
| | - Daina M Brooks
- Musculoskeletal Research Center, Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, 201 E University Pkwy, Baltimore, MD 21218, USA.
| | - Nicholas P Rolle
- Department of Surgery, Inova Fairfax Medical Campus, 3300 Gallows Rd., Falls Church, VA 22042, USA
| | - David A Weiner
- Department of Orthopaedic Surgery, MedStar Southern Maryland Hospital Center, 7503 Surratts Rd, Clinton, MD 20735, USA
| | - Wenhai Wang
- Musculoskeletal Education and Research Center, A Division of Globus Medical, Inc. 2560 General Armistead Ave, Audubon, PA 19403, USA
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Pivazyan G, Winters CG, Brooks DM, Sandhu FA, Cunningham BW. Biomechanical Analysis of 2 Versus 4 Rods Across the Cervicothoracic Junction in a Human Cadaveric Model. Neurosurgery 2024; 94:217-225. [PMID: 37706689 DOI: 10.1227/neu.0000000000002686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 07/27/2023] [Indexed: 09/15/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Posterior reconstruction of the cervicothoracic junction poses significant biomechanical challenges secondary to transition from the mobile cervical to rigid thoracic spines and change in alignment from lordosis to kyphosis. After destabilization, the objectives of the current investigation were to compare the rod strain and multidirectional flexibility properties of the cervicothoracic junction using a 4-rod vs traditional 2-rod reconstructions. METHODS Ten human cadaveric cervicothoracic specimens underwent multidirectional flexibility testing including flexion-extension, lateral bending, and axial rotation. After intact analysis, specimens were destabilized from C4 to T3 and instrumented from C3 to T4. The following reconstructions were tested: (1) 3.5-mm titanium (Ti) 2-rod, (2) 3.5-mm Ti 4-rod, (3) 4.0-mm cobalt chrome (CoCr) 2-rod, (4) 4.0-mm CoCr 4-rod, and (5) Ti 3.5- to 5.5-mm tapered rod reconstructions. The operative level range of motion and rod strain of the primary and accessory rods were quantified. RESULTS The addition of accessory rods to a traditional 2-rod construct improved the biomechanical stability of the reconstructions in all three loading modalities for Ti ( P < .05). The accessory CoCr rods improved stability in flexion-extension and axial rotation ( P < .05). The addition of accessory rods in Ti or CoCr reconstructions did not significantly reduce rod strain ( P < .05). CoCr 2 and 4 rods exhibited less strain than both Ti 2 and 4 rods. CONCLUSION Supplemental accessory rods affixed to traditional 2-rod constructs significantly improved stability of Ti alloys and CoCr alloy materials. The 4.0-mm CoCr rods provided greater stability than 3.5-mm Ti rods in flexion-extension, lateral bending, and axial rotation. While rod strain was not significantly reduced by the addition of accessory rods, it was reduced in CoCr rod treatment groups compared with the Ti rods.
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Affiliation(s)
- Gnel Pivazyan
- Department of Neurosurgery, MedStar Georgetown University Hospital, Washington , District of Columbia , USA
- Department of Orthopaedic Surgery, Musculoskeletal Research Center, MedStar Union Memorial Hospital, Baltimore , Maryland , USA
| | - Carlynn G Winters
- Georgetown University School of Medicine, Washington , District of Columbia , USA
| | - Daina M Brooks
- Department of Orthopaedic Surgery, Musculoskeletal Research Center, MedStar Union Memorial Hospital, Baltimore , Maryland , USA
- Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore , Maryland , USA
| | - Faheem A Sandhu
- Department of Neurosurgery, MedStar Georgetown University Hospital, Washington , District of Columbia , USA
| | - Bryan W Cunningham
- Department of Orthopaedic Surgery, Musculoskeletal Research Center, MedStar Union Memorial Hospital, Baltimore , Maryland , USA
- Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore , Maryland , USA
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Pivazyan G, Winters CG, Brooks DM, Sandhu FA, Cunningham BW. Cervicothoracic Reconstruction with Quad Rods, Dual Rods, and Tapered Rods: An in Vitro Human Cadaveric Model. World Neurosurg 2023; 180:243-244. [PMID: 37839569 DOI: 10.1016/j.wneu.2023.10.063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Affiliation(s)
- Gnel Pivazyan
- Department of Neurosurgery, MedStar Georgetown University Hospital, Washington, District of Columbia, USA; Department of Orthopaedic Surgery, Musculoskeletal Research Center, MedStar Union Memorial Hospital, Baltimore, Maryland, USA
| | - Carlynn G Winters
- Georgetown University School of Medicine, Washington, District of Columbia, USA
| | - Daina M Brooks
- Department of Orthopaedic Surgery, Musculoskeletal Research Center, MedStar Union Memorial Hospital, Baltimore, Maryland, USA; Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore, Maryland, USA
| | - Faheem A Sandhu
- Department of Neurosurgery, MedStar Georgetown University Hospital, Washington, District of Columbia, USA
| | - Bryan W Cunningham
- Department of Orthopaedic Surgery, Musculoskeletal Research Center, MedStar Union Memorial Hospital, Baltimore, Maryland, USA; Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore, Maryland, USA
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Abadeer AI, Wu CM, Brooks DM, Higgins JP, Giladi AM, Shubinets V. Arterial Perfusion of the Proximal Phalanx Revisited: New Insights Based on Micro-Computed Tomography. J Hand Surg Am 2022:S0363-5023(22)00573-1. [PMID: 36333245 DOI: 10.1016/j.jhsa.2022.09.014] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 09/08/2022] [Accepted: 09/21/2022] [Indexed: 11/06/2022]
Abstract
PURPOSE To characterize the periosteal and endosteal arterial perfusion of the proximal phalanx using micro-computed tomography angiography (micro-CTA). METHODS Cadaveric upper extremities were injected with a barium sulfate/gelatin suspension. Phalanges were imaged using micro-CTA and analyzed with a focus on osseous arterial anatomy. Periosteal and endosteal perfusion was characterized by number of vessels, length, anatomic course, and caliber. RESULTS The base of the proximal phalanx had a significantly greater number (8.0 ± 3.5) of periosteal vessels than those of the shaft (4.1 ± 1.6) and head (1.3 ± 1.1). One-third (34.4%) of the specimens demonstrated a complete absence of periosteal vessels in the head. A nutrient endosteal vessel was noted in 100% of the specimens. Entering at the junction of the middle and distal third of the bone (25.8 ± 3.9 mm from base), the nutrient vessel entered the proximal phalanx of the index finger along its ulnar aspect (8 of 8 specimens), the middle finger along its radial aspect (6 of 8), the ring finger along its ulnar aspect (5 of 8), and the little finger along its radial aspect (7 of 8). The nutrient vessel branched into proximal and distal extensions toward the shaft and head, respectively, with an average endosteal length of 10.7 ± 5.2 mm and average diameter of 0.36 ± 0.11 mm. CONCLUSIONS Periosteal contributions to the perfusion of the proximal phalanx appear to diminish distally. The endosteal arterial anatomy remains consistent, with a single nutrient vessel entering the intramedullary canal with reliable laterality on each digit. This is often the only vessel supplying the head of the proximal phalanx, making this area particularly susceptible to vascular compromise. CLINICAL RELEVANCE An understanding of the patterns of perfusion of the proximal phalanx provides some insight into clinically observed pathology, as well as guidance for operative management.
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Affiliation(s)
- Andrew I Abadeer
- The Curtis National Hand Center, Medstar Union Memorial Hospital, Baltimore, MD; Georgetown University School of Medicine, Washington, DC
| | - Caroline M Wu
- The Curtis National Hand Center, Medstar Union Memorial Hospital, Baltimore, MD; Georgetown University School of Medicine, Washington, DC
| | - Daina M Brooks
- Musculoskeletal Research Center, Department of Orthopedic Surgery, MedStar Union Memorial Hospital, Baltimore, MD
| | - James P Higgins
- The Curtis National Hand Center, Medstar Union Memorial Hospital, Baltimore, MD
| | - Aviram M Giladi
- The Curtis National Hand Center, Medstar Union Memorial Hospital, Baltimore, MD
| | - Valeriy Shubinets
- The Curtis National Hand Center, Medstar Union Memorial Hospital, Baltimore, MD.
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McAfee PC, Cunningham BW, Mullinex K, Eisermann L, Brooks DM. Computer Simulated Enhancement and Planning, Robotics and Navigation With Patient Specific Implants and 3-D Printed Cages. Global Spine J 2022; 12:7S-18S. [PMID: 35393879 PMCID: PMC8998477 DOI: 10.1177/21925682211003554] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
STUDY DESIGN This is a retrospective cohort study. OBJECTIVES Pre and postop Measurement Testing. This is a retrospective study of 33 consecutive interbody spacers in 21 patients who underwent pre, intra, and postoperative measurement of the middle column to determine if this would lead to more precise restoration of middle column height and spacer fit. Scaled transparencies of the pre-operative simulation of angular correction and spacer geometry could be overlayed on the post-operative imaging studies. METHODS Multiple Observers Measurement Testing. 33 consecutive vertebral levels requiring interbody spacers for multilevel deformities had middle column height pre and post operatively measured by 3 blinded observers. The preoperative and postoperative measurements were compared using a linear regression analysis and Pearson product-moment correlation. RESULTS Pre and postop Measurement Testing: Thirty-three interbody devices in 21 patients had pre-operative planning, simulation of cage dimensions to determine the proper cage fit which would provide for the desired correction of foraminal height and sagittal balance parameters. The simulated preoperative plan overlayed the final post-operative radiograph and was a near-perfect match in 20 of 21 patients (95.2%). Multiple Observers Measurement Testing: A Pearson product-moment correlation was run between each individual's pre-op and post-op middle column measurements. There was a strong, positive correlation between pre-operative and post-operative measurements, which was statistically significant (r = 0.903, n = 33, P < 0.001). CONCLUSIONS This consecutive series of 33 cases demonstrated the utility of measuring the preoperative middle column length in predicting the optimal height of the spacers, intervertebral disks, and posterior vertebral body height simultaneously restoring sagittal and coronal plane alignment.
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Affiliation(s)
- Paul C. McAfee
- MedStar Orthopedic Institute, Union Memorial Hospital, Baltimore, MD, USA
| | | | - Ken Mullinex
- MedStar Orthopedic Institute, Union Memorial Hospital, Baltimore, MD, USA
| | - Lukas Eisermann
- MedStar Orthopedic Institute, Union Memorial Hospital, Baltimore, MD, USA
| | - Daina M. Brooks
- MedStar Orthopedic Institute, Union Memorial Hospital, Baltimore, MD, USA
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Abstract
STUDY DESIGN Systematic review. OBJECTIVES The optoelectronic camera source and data interpolation process serve as the foundation for navigational integrity in robotic-assisted surgical platforms. The current systematic review serves to provide a basis for the numerical disparity observed when comparing the intrinsic accuracy of optoelectronic cameras versus accuracy in the laboratory setting and clinical operative environments. METHODS Review of the PubMed and Cochrane Library research databases was performed. The exhaustive literature compilation obtained was then vetted to reduce redundancies and categorized into topics of intrinsic accuracy, registration accuracy, musculoskeletal kinematic platforms, and clinical operative platforms. RESULTS A total of 465 references were vetted and 137 comprise the basis for the current analysis. Regardless of application, the common denominators affecting overall optoelectronic accuracy are intrinsic accuracy, registration accuracy, and application accuracy. Intrinsic accuracy equaled or was less than 0.1 mm translation and 0.1 degrees rotation per fiducial. Controlled laboratory platforms reported 0.1 to 0.5 mm translation and 0.1 to 1.0 degrees rotation per array. Accuracy in robotic-assisted spinal surgery reported 1.5 to 6.0 mm translation and 1.5 to 5.0 degrees rotation when comparing planned to final implant position. CONCLUSIONS Navigational integrity and maintenance of fidelity of optoelectronic data is the cornerstone of robotic-assisted spinal surgery. Transitioning from controlled laboratory to clinical operative environments requires an increased number of steps in the optoelectronic kinematic chain and error potential. Diligence in planning, fiducial positioning, system registration and intra-operative workflow have the potential to improve accuracy and decrease disparity between planned and final implant position.
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Affiliation(s)
- Bryan W. Cunningham
- Department of Orthopaedic Surgery, Musculoskeletal Research and Innovation Institute, MedStar Union Memorial Hospital, Baltimore, MD, USA
- Department of Orthopaedic Surgery, Georgetown University School of Medicine, Washington, DC, USA
| | - Daina M. Brooks
- Department of Orthopaedic Surgery, Musculoskeletal Research and Innovation Institute, MedStar Union Memorial Hospital, Baltimore, MD, USA
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Cunningham BW, Brooks DM, McAfee PC. Accuracy of Robotic-Assisted Spinal Surgery-Comparison to TJR Robotics, da Vinci Robotics, and Optoelectronic Laboratory Robotics. Int J Spine Surg 2021; 15:S38-S55. [PMID: 34607917 PMCID: PMC8532535 DOI: 10.14444/8139] [Citation(s) in RCA: 2] [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] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND The optoelectronic camera source and data interpolation serve as the foundation for navigational integrity in the robotic-assisted surgical platform. The objective of the current systematic review serves to provide a basis for the numerical disparity that exists when comparing the intrinsic accuracy of optoelectronic cameras: accuracy observed in the laboratory setting versus accuracy in the clinical operative environment. It is postulated that there exists a greater number of connections in the optoelectronic kinematic chain when analyzing the clinical operative environment to the laboratory setting. This increase in data interpolation, coupled with intraoperative workflow challenges, reduces the degree of accuracy based on surgical application and to that observed in controlled musculoskeletal kinematic laboratory investigations. METHODS Review of the PubMed and Cochrane Library research databases was performed. The exhaustive literature compilation obtained was then vetted to reduce redundancies and categorized into topics of intrinsic optoelectronic accuracy, registration accuracy, musculoskeletal kinematic platforms, and clinical operative platforms. RESULTS A total of 147 references make up the basis for the current analysis. Regardless of application, the common denominators affecting overall optoelectronic accuracy are intrinsic accuracy, registration accuracy, and application accuracy. Intrinsic accuracy of optoelectronic tracking equaled or was less than 0.1 mm of translation and 0.1° of rotation per fiducial. Controlled laboratory platforms reported 0.1 to 0.5 mm of translation and 0.1°-1.0° of rotation per array. There is a huge falloff in clinical applications: accuracy in robotic-assisted spinal surgery reported 1.5 to 6.0 mm of translation and 1.5° to 5.0° of rotation when comparing planned to final implant position. Total Joint Robotics and da Vinci urologic robotics computed accuracy, as predicted, lies between these two extremes-1.02 mm for da Vinci and 2 mm for MAKO. CONCLUSIONS Navigational integrity and maintenance of fidelity of optoelectronic data is the cornerstone of robotic-assisted spinal surgery. Transitioning from controlled laboratory to clinical operative environments requires an increased number of steps in the optoelectronic kinematic chain and error potential. Diligence in planning, fiducial positioning, system registration, and intraoperative workflow have the potential to improve accuracy and decrease disparity between planned and final implant position. The key determining factors limiting navigation resolution accuracy are highlighted by this Cochrane research analysis.
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Affiliation(s)
- Bryan W. Cunningham
- Musculoskeletal Education Center, Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore, Maryland
- Department of Orthopaedic Surgery, Georgetown University School of Medicine, Washington, D.C
| | - Daina M. Brooks
- Musculoskeletal Education Center, Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore, Maryland
| | - Paul C. McAfee
- Musculoskeletal Education Center, Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore, Maryland
- Department of Orthopaedic Surgery, Georgetown University School of Medicine, Washington, D.C
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Ou-Yang D, Moldavsky M, Wessell N, Brooks DM, Titanti M, Matheis EA, Bucklen BS, Patel V. Evaluation of Spinous Process Tethering at the Proximal End of Rigid Constructs: In Vitro Range of Motion and Intradiscal Pressure at Instrumented and Adjacent Levels. Int J Spine Surg 2020; 14:571-579. [PMID: 32986580 DOI: 10.14444/7076] [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: 11/20/2022] Open
Abstract
BACKGROUND Adult spinal deformity surgery requires use of long thoracolumbar instrumentation, which is associated with risk of postoperative proximal junctional kyphosis (PJK). Tethering has been used in spinal surgery but not around the spinous process (SP) in the context of preventing PJK. METHODS Researchers applied a nondestructive hybrid loading protocol to 7 T8-L2 cadaveric specimens in flexion-extension, lateral bending, and axial rotation (AR). A rigid construct (pedicle screws and rods) and 1- and 2-level SP constructs were tested, as was a hand-tie technique. SP tethering (SPT) constructs use clamps on both sides of the SP; SPT helix constructs use 1 clamp and wrap around the SP. RESULTS All tether constructs showed greater motion at the instrumented level and less motion at adjacent levels compared to rigid constructs. In AR, 1- and 2-level SPT constructs restricted first instrumented level motion to a greater extent when compared with other tether constructs (P ≤ .05). Passing the band through the T10 SP did not produce significant biomechanical differences compared to passing it through the T9-T10 interspinous ligament (P > .05). Hand-tied constructs demonstrated more motion compared to tensioned constructs (P > .05). Intradiscal pressure results corroborated motion data. CONCLUSIONS SPT at the proximal end of a rigid construct produced more favorable biomechanical outcomes at instrumented and adjacent levels than were seen with a completely rigid construct. Clinical research is needed to determine whether these methods reduce the risk of PJK among patients. LEVEL OF EVIDENCE 3. CLINICAL RELEVANCE This work sheds light on the biomechanical stability of proximal tethering constructs in an effort to enhance the surgeon's ability to reduce rates of proximal junctional kyphosis and failure in thoracolumbar spinal fusion surgery.
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Affiliation(s)
- David Ou-Yang
- The Spine Center at University of Colorado Hospital, Aurora, Colorado
| | - Mark Moldavsky
- Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical, Inc., Audubon, Pennsylvania
| | - Nolan Wessell
- The Spine Center at University of Colorado Hospital, Aurora, Colorado
| | - Daina M Brooks
- Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical, Inc., Audubon, Pennsylvania
| | - Mariano Titanti
- Department of Mechanical Engineering and Mechanics, College of Engineering, Drexel University, Philadelphia, Pennsylvania
| | - Erika A Matheis
- Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical, Inc., Audubon, Pennsylvania
| | - Brandon S Bucklen
- Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical, Inc., Audubon, Pennsylvania
| | - Vikas Patel
- The Spine Center at University of Colorado Hospital, Aurora, Colorado
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Leung E, Maingard J, Yeh J, Lee MJ, Brooks DM, Asadi H, Burrows DA, Kok HK. Contemporary endovascular management of splenic vascular pathologies. Clin Radiol 2020; 75:960.e23-960.e34. [PMID: 32819705 DOI: 10.1016/j.crad.2020.07.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 07/06/2020] [Indexed: 11/28/2022]
Abstract
The spleen is a commonly injured organ and the splenic vasculature is also susceptible to inflammation and trauma, often resulting in aneurysm formation. Splenic artery aneurysms carry a high risk of rupture and are associated with high mortality and morbidity. Due to the advances in endovascular techniques and devices, endovascular management of splenic vascular pathologies is now considered a first-line strategy. Endovascular embolisation and advance techniques including balloon- or stent-assisted coil embolisation enables minimally invasive management option while preserving splenic function.
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Affiliation(s)
- E Leung
- Interventional Radiology Service - Department of Radiology, Northern Health, Melbourne, Australia.
| | - J Maingard
- Interventional Neuroradiology Service - Monash Imaging, Monash Health, Melbourne, Australia; School of Medicine, Faculty of Health, Deakin University, Waurn Ponds, Australia
| | - J Yeh
- Interventional Radiology Service - Department of Radiology, Northern Health, Melbourne, Australia
| | - M J Lee
- Department of Radiology, Beaumont Hospital and Royal College of Surgeons in Ireland, Dublin, Ireland
| | - D M Brooks
- School of Medicine, Faculty of Health, Deakin University, Waurn Ponds, Australia; Interventional Neuroradiology Service - Radiology Department, Austin Hospital, Melbourne, Australia
| | - H Asadi
- Interventional Neuroradiology Service - Monash Imaging, Monash Health, Melbourne, Australia; School of Medicine, Faculty of Health, Deakin University, Waurn Ponds, Australia; Interventional Neuroradiology Service - Radiology Department, Austin Hospital, Melbourne, Australia
| | - D A Burrows
- Interventional Radiology Service - Department of Radiology, Northern Health, Melbourne, Australia
| | - H K Kok
- Interventional Radiology Service - Department of Radiology, Northern Health, Melbourne, Australia; School of Medicine, Faculty of Health, Deakin University, Waurn Ponds, Australia
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Rahm MD, Brooks DM, Harris JA, Hart RA, Hughes JL, Ferrick BJ, Bucklen BS. Stabilizing effect of the rib cage on adjacent segment motion following thoracolumbar posterior fixation of the human thoracic cadaveric spine: A biomechanical study. Clin Biomech (Bristol, Avon) 2019; 70:217-222. [PMID: 31669919 DOI: 10.1016/j.clinbiomech.2019.10.008] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 09/19/2019] [Accepted: 10/05/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Although the rib cage provides substantial stability to the thoracic spine, few biomechanical studies have incorporated it into their testing model, and no studies have determined the influence of the rib cage on adjacent segment motion of long fusion constructs. The present biomechanical study aimed to determine the mechanical contribution of the intact rib cage during the testing of instrumented specimens. METHODS A cyclic loading (CL) protocol with instrumentation (T4-L2 pedicle screw-rod fixation) was conducted on five thoracic spines (C7-L2) with intact rib cages. Range of motion (±5 Nm pure moment) in flexion-extension, lateral bending, and axial rotation was captured for intact ribs, partial ribs, and no ribs conditions. Comparisons at the supra-adjacent (T2-T3), adjacent (T3-T4), first instrumented (T4-T5), and second instrumented (T5-T6) levels were made between conditions (P ≤ 0.05). FINDINGS A trend of increased motion at the adjacent level was seen for partial ribs and no ribs in all 3 bending modes. This trend was also observed at the supra-adjacent level for both conditions. No significant changes in motion compared to the intact ribs condition were seen at the first and second instrumented levels (P > 0.05). INTERPRETATION The segment adjacent to long fusion constructs, which may appear more grossly unstable when tested in the disarticulated spine, is reinforced by the rib cage. In order to avoid overestimating adjacent level motion, when testing the effectiveness of surgical techniques of the thoracic spine, inclusion of the rib cage may be warranted to better reflect clinical circumstances.
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Affiliation(s)
- Mark D Rahm
- Department of Orthopaedic Surgery, Baylor Scott and White Health/Texas A&M University College of Medicine, 2401 S 31(st) Street, Temple, Texas, 76508, USA.
| | - Daina M Brooks
- Musculoskeletal Education and Research Center, Globus Medical, Inc., 2560 General Armistead Avenue, Audubon, PA 19403, USA.
| | - Jonathan A Harris
- Musculoskeletal Education and Research Center, Globus Medical, Inc., 2560 General Armistead Avenue, Audubon, PA 19403, USA.
| | - Robert A Hart
- Department of Orthopaedic Surgery, Swedish Neuroscience Institute, 601 Broadway, Seattle, WA 98122, USA.
| | - Jessica L Hughes
- Department of Orthopaedic Surgery, Baylor Scott and White Health/Texas A&M University College of Medicine, 2401 S 31(st) Street, Temple, Texas, 76508, USA.
| | - Bryan J Ferrick
- Drexel University School of Biomedical Engineering, Science and Health Systems, 3141 Chestnut Street, Philadelphia, PA 19104, USA
| | - Brandon S Bucklen
- Musculoskeletal Education and Research Center, Globus Medical, Inc., 2560 General Armistead Avenue, Audubon, PA 19403, USA.
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Dall BE, Eden SV, Cho W, Karkenny A, Brooks DM, Hayward GM, Moldavsky M, Yandamuri S, Bucklen BS. Biomechanical analysis of motion following sacroiliac joint fusion using lateral sacroiliac screws with or without lumbosacral instrumented fusion. Clin Biomech (Bristol, Avon) 2019; 68:182-189. [PMID: 31234032 DOI: 10.1016/j.clinbiomech.2019.05.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [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: 11/19/2018] [Revised: 05/10/2019] [Accepted: 05/15/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Sacroiliac joint hypermobility or aberrant mechanics may be a source of pain. The purpose of this study was to assess sacroiliac joint range of motion after simulated adjacent lumbosacral instrumented fusion, with or without sacroiliac joint fusion, with lateral sacroiliac screws. METHODS In this in vitro biomechanical study, seven cadaveric specimens were tested on a six-degrees-of-freedom machine under load control. Left posterior sacroiliac joint ligaments were severed to maximize joint range of motion. Influence of lumbosacral instrumentation on sacroiliac joint motion, with or without fixation, was studied. FINDINGS During flexion-extension in the setting of posterior sacroiliac joint injury and L5-S1 fixation, sacroiliac joint range of motion increased to 195% of intact. After fixation with lateral sacroiliac screws, average range of motion reduced to 144% of intact motion. Sacroiliac joint screws thus partially stabilized the joint and reduced motion. Use of 6 bilateral sacroiliac joint screws with L5-S1 screw and rod fixation in lateral bending and axial rotation yielded the greatest reduction in range of motion. Without lumbosacral fixation, baseline motion of the sacroiliac joint was reduced, and sacroiliac joint screw alone, using either 2, 3, or 6 screws, was able to restore motion at or below the level of an intact joint. INTERPRETATION Sacroiliac joint ligament injury with existing lumbosacral fixation doubled sacroiliac joint range of motion, but thereafter, fixation with lateral sacroiliac screws decreased range of motion of the injured sacroiliac joint. Screw configuration played a minor role, but generally, 6 sacroiliac joint screws had the greatest motion reduction.
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Affiliation(s)
- Bruce E Dall
- Borgess Brain and Spine Institute, 1521 Gull Road, Kalamazoo, MI 49048, USA
| | - Sonia V Eden
- Borgess Brain and Spine Institute, 1521 Gull Road, Kalamazoo, MI 49048, USA; Western Michigan University University Homer Stryker md School of Medicine, 300 Portage Street, Kalamazoo, MI 49007
| | - Woojin Cho
- Montefiore Medical Center, 3400 Bainbridge Ave, 6th Fl., Bronx, NY 10467, USA
| | - Alexa Karkenny
- Montefiore Medical Center, 3400 Bainbridge Ave, 6th Fl., Bronx, NY 10467, USA
| | - Daina M Brooks
- Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical, Inc., 2560 General Armistead Avenue, Audubon, PA 19403, USA
| | - Gerald M Hayward
- Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical, Inc., 2560 General Armistead Avenue, Audubon, PA 19403, USA.
| | - Mark Moldavsky
- Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical, Inc., 2560 General Armistead Avenue, Audubon, PA 19403, USA
| | - Soumya Yandamuri
- Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical, Inc., 2560 General Armistead Avenue, Audubon, PA 19403, USA
| | - Brandon S Bucklen
- Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical, Inc., 2560 General Armistead Avenue, Audubon, PA 19403, USA
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12
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Mushlin H, Brooks DM, Olexa J, Ferrick BJ, Carbine S, Hayward GM, Bucklen BS, Sansur CA. A biomechanical investigation of the sacroiliac joint in the setting of lumbosacral fusion: impact of pelvic fixation versus sacroiliac joint fixation. J Neurosurg Spine 2019; 31:1-6. [PMID: 31200368 DOI: 10.3171/2019.3.spine181127] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [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: 09/25/2018] [Accepted: 03/22/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The sacroiliac joint (SIJ) is a known source of low-back pain. Randomized clinical trials support sacroiliac fusion over conservative management for SIJ dysfunction. Clinical studies suggest that SIJ degeneration occurs in the setting of lumbosacral fusions. However, there are few biomechanical studies to provide a good understanding of the effect of lumbosacral fusion on the SIJ. In the present study, researchers performed a biomechanical investigation to discern the effect of pelvic versus SIJ fixation on the SIJ in lumbosacral fusion. METHODS Seven fresh-frozen human cadaveric specimens were used. There was one intact specimen and six operative constructs: 1) posterior pedicle screws and rods from T10 to S1 (PS); 2) PS + bilateral iliac screw fixation (BIS); 3) PS + unilateral iliac screw fixation (UIS); 4) PS + UIS + 3 contralateral unilateral SIJ screws (UIS + 3SIJ); 5) PS + 3 unilateral SIJ screws (3SIJ); and 6) PS + 6 bilateral SIJ screws (6SIJ). A custom-built 6 degrees-of-freedom apparatus was used to simulate three bending modes: flexion-extension (FE), lateral bending (LB), and axial rotation (AR). Range of motion (ROM) was recorded at L5-S1 and the SIJ. RESULTS All six operative constructs had significantly reduced ROM at L5-S1 in all three bending modes compared to that of the intact specimen (p < 0.05). In the FE mode, the BIS construct had a significant reduction in L5-S1 ROM as compared to the other five constructs (p < 0.05). SIJ ROM was greatest in the FE mode compared to LB and AR. Although the FE mode did not show any statistically significant differences in SIJ ROM across the constructs, there were appreciable differences. The PS construct had the highest SIJ ROM. The BIS construct reduced bilateral SIJ ROM by 44% in comparison to the PS construct. The BIS and 6SIJ constructs showed reductions in SIJ ROM nearly equal to those of the PS construct. UIS and 3SIJ showed an appreciable reduction in unfused SIJ ROM compared to PS. CONCLUSIONS This investigation demonstrated the effects of various fusion constructs using pelvic and sacroiliac fixation in lumbosacral fusion. This study adds biomechanical evidence of adjacent segment stress in the SIJ in fusion constructs extending to S1. Unilateral pelvic fixation, or SIJ fusion, led to an appreciable but nonsignificant reduction in the ROM of the unfused contralateral SIJ. Bilateral pelvic fixation showed the greatest significant reduction of movement at L5-S1 and was equivalent to bilateral sacroiliac fusion in reducing SIJ motion.
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Affiliation(s)
- Harry Mushlin
- 1Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Daina M Brooks
- 2Musculoskeletal Education and Research Center (MERC), a Division of Globus Medical Inc., Audubon; and
| | - Joshua Olexa
- 1Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Bryan J Ferrick
- 3School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania
| | - Stephen Carbine
- 1Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Gerald M Hayward
- 2Musculoskeletal Education and Research Center (MERC), a Division of Globus Medical Inc., Audubon; and
| | - Brandon S Bucklen
- 2Musculoskeletal Education and Research Center (MERC), a Division of Globus Medical Inc., Audubon; and
| | - Charles A Sansur
- 1Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
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13
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Frisch RF, Luna IY, Brooks DM, Joshua G, O'Brien JR. Clinical and radiographic analysis of expandable versus static lateral lumbar interbody fusion devices with two-year follow-up. J Spine Surg 2018; 4:62-71. [PMID: 29732424 DOI: 10.21037/jss.2018.03.16] [Citation(s) in RCA: 18] [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] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Utilization of static and expandable interbody spacers for minimally invasive lateral lumbar interbody fusion (LLIF) offers favorable clinical results. However, complications such as implant migration and/or subsidence may occur with a static implant. Expandable devices allow for in situ expansion to optimize fit and mitigate iatrogenic endplate damage during trialing and impaction. This study sought to compare clinical and radiographic outcomes of static and expandable spacers following LLIF and report device-related complications. Methods This study included 29 patients who underwent LLIF with a static spacer and 27 with an expandable spacer; all procedures were combined with supplemental transpedicular posterior fixation. Patient self-assessment forms and radiographic records were used to assess clinical and radiologic outcomes. Results Mean patient age was 62.3±10.3 years (64% female). One-level surgery was performed in 87.5% of patients, and 12.5% underwent two-level surgery. Results showed no significant differences in blood loss or length of hospital stay (P>0.05). However, operative times differed statistically between static (63.3±37.8 min) and expandable (120.2±59.6 min) groups (P=0.000). Mean visual analog scale (VAS) and Oswestry Disability Index (ODI) scores improved significantly from preoperative to 24-month follow-up in both groups (P<0.05). Preoperative intervertebral and neuroforaminal height increased significantly in both groups (P<0.01). Fusion was observed in all operative levels in the static and expandable spacer groups by 24-month follow-up. Implant subsidence was reported in 16.1% of static levels and none of the expandable levels (P<0.01). Postoperative radiographs showed no evidence of implant migration, and no cases required surgical revision at the index or adjacent levels. Conclusions LLIF using expandable spacers resulted in similar clinical and radiographic outcomes when compared with using static spacers, and led to a lower subsidence rate.
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Affiliation(s)
| | - Ingrid Y Luna
- Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical, Inc., Audubon, PA, USA
| | - Daina M Brooks
- Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical, Inc., Audubon, PA, USA
| | - Gita Joshua
- Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical, Inc., Audubon, PA, USA
| | - Joseph R O'Brien
- The George Washington University School of Medicine & Health Sciences, Washington, DC, USA
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14
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Panchal RR, Kim KD, Eastlack R, Lopez J, Clavenna A, Brooks DM, Joshua G. A Clinical Comparison of Anterior Cervical Plates Versus Stand-Alone Intervertebral Fusion Devices for Single-Level Anterior Cervical Discectomy and Fusion Procedures. World Neurosurg 2016; 99:630-637. [PMID: 28017756 DOI: 10.1016/j.wneu.2016.12.060] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [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: 10/17/2016] [Revised: 12/12/2016] [Accepted: 12/14/2016] [Indexed: 12/26/2022]
Abstract
OBJECTIVE To compare radiologic and clinical outcomes, including rates of dysphagia and dysphonia, using a no-profile stand-alone intervertebral spacer with integrated screw fixation versus an anterior cervical plate and spacer construct for single-level anterior cervical discectomy and fusion (ACDF) procedures. METHODS This multicenter, randomized, prospective study included 54 patients with degenerative disc disease requiring ACDF at a single level at C3-C7. Twenty-six patients underwent single-level ACDF with stand-alone spacers, and 28 with plate fixation and spacers. Analyses were based on comparison of perioperative outcomes, radiologic and clinical metrics, and incidence of dysphagia and/or dysphonia. RESULTS Mean patient age was 48.8 ± 10.1years (53.7% female). No significant differences were observed between groups in operative time (101.8 ± 34.4 minutes, 114.4 ± 31.5 minutes), estimated blood loss (44.8 ± 76.5 mL, 82.5 ± 195.1 mL), or length of hospital stay (1.2 ± 0.6 days, 1.3 ± 0.6 days). Mean visual analog scale pain scores and Neck Disability Index scores improved significantly from preoperative to last follow-up (10.8 ± 2.6 months) in both groups (P < 0.05). Mean Voice Handicap Index and Eating Assessment Tool scores improved significantly from discharge to last follow-up in both groups (P < 0.05). From discharge to 6 months, the stand-alone spacers group consistently demonstrated greater improvement in Voice Handicap Index. Preoperative intervertebral disc and neuroforaminal heights increased significantly across treatment groups (P < 0.01), and no cases required surgical revision at index or adjacent levels. CONCLUSIONS Anterior cervical discectomy and fusion with stand-alone spacers resulted in similar clinical and radiologic outcomes as compared with plate and spacers and may help minimize postoperative dysphonia.
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Affiliation(s)
- Ripul R Panchal
- Department of Neurological Surgery, University of California, Davis Medical Center, Sacramento, California, USA.
| | - Kee D Kim
- Department of Neurological Surgery, University of California, Davis Medical Center, Sacramento, California, USA
| | | | - John Lopez
- Spine Care Specialists of Alaska, Fairbanks, Arkansas, USA
| | | | - Daina M Brooks
- Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical, Inc., Audubon, Pennsylvania, USA
| | - Gita Joshua
- Musculoskeletal Education and Research Center (MERC), A Division of Globus Medical, Inc., Audubon, Pennsylvania, USA
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15
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Jaimes R, Kuzmiak-Glancy S, Brooks DM, Swift LM, Posnack NG, Kay MW. Functional response of the isolated, perfused normoxic heart to pyruvate dehydrogenase activation by dichloroacetate and pyruvate. Pflugers Arch 2015; 468:131-142. [PMID: 26142699 DOI: 10.1007/s00424-015-1717-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 06/17/2015] [Accepted: 06/22/2015] [Indexed: 12/19/2022]
Abstract
Dichloroacetate (DCA) and pyruvate activate pyruvate dehydrogenase (PDH), a key enzyme that modulates glucose oxidation and mitochondrial NADH production. Both compounds improve recovery after ischemia in isolated hearts. However, the action of DCA and pyruvate in normoxic myocardium is incompletely understood. We measured the effect of DCA and pyruvate on contraction, mitochondrial redox state, and intracellular calcium cycling in isolated rat hearts during normoxic perfusion. Normalized epicardial NADH fluorescence (nNADH) and left ventricular developed pressure (LVDP) were measured before and after administering DCA (5 mM) or pyruvate (5 mM). Optical mapping of Rhod-2AM was used to measure cytosolic calcium kinetics. DCA maximally activated PDH, increasing the ratio of active to total PDH from 0.48 ± 0.03 to 1.03 ± 0.03. Pyruvate sub-maximally activated PDH to a ratio of 0.75 ± 0.02. DCA and pyruvate increased LVDP. When glucose was the only exogenous fuel, pyruvate increased nNADH by 21.4 ± 2.9 % while DCA reduced nNADH by 21.4 ± 6.1 % and elevated the incidence of premature ventricular contractions (PVCs). When lactate, pyruvate, and glucose were provided together as exogenous fuels, nNADH increased with DCA, indicating that PDH activation with glucose as the only exogenous fuel depletes PDH substrate. Calcium transient time-to-peak was shortened by DCA and pyruvate and SR calcium re-uptake was 30 % longer. DCA and pyruvate increased SR calcium load in myocyte monolayers. Overall, during normoxia when glucose is the only exogenous fuel, DCA elevates SR calcium, increases LVDP and contractility, and diminishes mitochondrial NADH. Administering DCA with plasma levels of lactate and pyruvate mitigates the drop in mitochondrial NADH and prevents PVCs.
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Affiliation(s)
- Rafael Jaimes
- Department of Biomedical Engineering, The George Washington University, GWU Science and Engineering Hall, 800 22nd Street NW, Suite 5000, Washington, DC, 20052, USA
| | - Sarah Kuzmiak-Glancy
- Department of Biomedical Engineering, The George Washington University, GWU Science and Engineering Hall, 800 22nd Street NW, Suite 5000, Washington, DC, 20052, USA
| | - Daina M Brooks
- Department of Biomedical Engineering, The George Washington University, GWU Science and Engineering Hall, 800 22nd Street NW, Suite 5000, Washington, DC, 20052, USA
| | - Luther M Swift
- Department of Pharmacology and Physiology, The George Washington University, Washington, DC, 20052, USA
| | - Nikki G Posnack
- Department of Pharmacology and Physiology, The George Washington University, Washington, DC, 20052, USA
| | - Matthew W Kay
- Department of Biomedical Engineering, The George Washington University, GWU Science and Engineering Hall, 800 22nd Street NW, Suite 5000, Washington, DC, 20052, USA.
- Department of Pharmacology and Physiology, The George Washington University, Washington, DC, 20052, USA.
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16
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Brooks DM. Psoas compartment block. CRNA 2000; 11:62-5. [PMID: 11271041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
The psoas compartment acts as a conduit for the nerve roots of the lumbar plexus. Originating at approximately the 12th thoracic vertebrae, this potential compartment continues on caudally, bordered posterolaterally by fascia of the quadratus lumborum and iliacus muscles, medially by the fascia of the psoas major muscle, and anteriorly by the transversalis fascia. This natural "gutter" acts as a repository for local anesthetic agents and provides an excellent method of unilateral anterior lower extremity anesthesia. After elicitation of a motor evoked response in the muscles of the anterior thigh, 30 to 40 milliliters of local anesthetic is incrementally injected into the compartment. Spread of the anesthetic to all roots of the plexus occurs in 15 to 20 minutes. Profound sensory and motor blockade can be achieved providing surgical anesthesia as well as long duration postoperative pain relief.
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Affiliation(s)
- D M Brooks
- Naval Medical Center Portsmouth, Portsmouth, VA, USA
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17
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Kloek AP, Brooks DM, Kunkel BN. A dsbA mutant of Pseudomonas syringae exhibits reduced virulence and partial impairment of type III secretion. Mol Plant Pathol 2000; 1:139-150. [PMID: 20572960 DOI: 10.1046/j.1364-3703.2000.00016.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Abstract To identify virulence genes of P. syringae pv. tomato strain DC3000 we screened for mutants with reduced virulence on its plant hosts, Arabidopsis thaliana and tomato. We isolated a Tn5-insertion mutant that exhibited reduced virulence on both hosts. Further characterization showed that this mutant carried a single Tn5 insertion in the dsbA gene, which encodes a periplasmic disulphide bond-forming protein. In addition to reduced virulence, the dsbA mutant exhibits mucoid colony morphology, loss of fluorescence, decreased motility, and a reduced growth rate in culture. The dsbA mutant is able to multiply in A. thaliana and tomato plants, trigger the hypersensitive response on tobacco and elicit Pto-mediated resistance in tomato, indicating that type III secretion occurs in this background. However, type III secretion appears to function with reduced efficiency in the dsbA mutant, as type III-dependent secretion of HrpZ and AvrRpt2 is impaired. These findings indicate that while the dsbA gene is required for multiple cellular functions in P. syringae, type III secretion in P. syringae is only partially dependent on dsbA.
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Affiliation(s)
- A P Kloek
- Department of Biology, Washington University, St. Louis, MO 63130, USA
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18
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Abstract
Three cases of percutaneous mechanical thrombectomy using the Amplatz thrombectomy device are presented. All cases involve the application of the device in a major thoracic or abdominal vein in situations in which chemothrombolysis was contraindicated. The method of operation of the Amplatz thrombectomy device, as well as a brief overview of its clinical applications, are presented.
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Affiliation(s)
- G J Smith
- Department of Radiology, Austin and Repatriation Medical Centre, Melbourne, Victoria, Australia
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19
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Super HJ, Hasenkrug KJ, Simmons S, Brooks DM, Konzek R, Sarge KD, Morimoto RI, Jenkins NA, Gilbert DJ, Copeland NG, Frankel W, Chesebro B. Fine mapping of the friend retrovirus resistance gene, Rfv3, on mouse chromosome 15. J Virol 1999; 73:7848-52. [PMID: 10438878 PMCID: PMC104315 DOI: 10.1128/jvi.73.9.7848-7852.1999] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rfv3 is a host resistance gene that operates through an unknown mechanism to control the development of the virus-neutralizing antibody response required for recovery from infection with Friend retrovirus. The Rfv3 gene was previously mapped to an approximately 20-centimorgan (cM) region of chromosome 15. More refined mapping was not possible, due to a lack of microsatellite markers and leakiness in the Rfv3 phenotype, which prevented definitive phenotyping of individual recombinant mice. In the present study, we overcame these difficulties by taking advantage of seven new microsatellite markers in the Rfv3 region and by using progeny tests to accurately determine the Rfv3 phenotype of recombinant mice. Detailed linkage analysis of relevant crossovers narrowed the location of Rfv3 to a 0.83-cM region. Mapping of closely linked genes in an interspecific backcross panel allowed us to exclude two previous candidate genes, Ly6 and Wnt7b. These studies also showed for the first time that the Hsf1 gene maps to the Rfv3-linked cluster of genes including Il2rb, Il3rb, and Pdgfb. This localization of Rfv3 to a region of less than 1 cM now makes it feasible to attempt the cloning of Rfv3 by physical methods.
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Affiliation(s)
- H J Super
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840, USA
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20
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Abstract
Many human viruses not only cause acute diseases but also establish persistent infections. Such persistent viruses can cause chronic diseases or can reactivate to cause acute diseases in AIDS patients or patients receiving immunosuppressive therapies. While the prevention of persistent infections is an important consideration in the design of modern vaccines, surprisingly little is known about this aspect of protection. In the current study, we tested the feasibility of vaccine prevention of retroviral persistence by using a Friend virus model that we recently developed. In this model, persistent virus can be detected at very low levels by immunosuppressing the host to reactivate virus or by transferring persistently infected spleen cells into highly susceptible mice. Two vaccines were analyzed, a recombinant vaccinia virus vector expressing Friend virus envelope protein and a live attenuated Friend virus. Both vaccines reduced pathogenic virus loads to levels undetectable by infectious center assays. However, only the live, attenuated vaccine prevented immunosuppression-induced reactivation of persistent virus. Thus, even very low levels of persistent Friend virus posed a significant threat during immunosuppression. Our results demonstrate that vaccine protection against establishment of retroviral persistence is attainable.
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Affiliation(s)
- U Dittmer
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana 59840, USA
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21
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Brooks DM, Hand WR. A cost analysis: general endotracheal versus regional versus monitored anesthesia care. Mil Med 1999; 164:303-5. [PMID: 10226461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
A prospective study was conducted to compare the total cost of all consumable products used to perform a general endotracheal anesthetic (GETA), a regional anesthetic, and a monitored anesthetic (MAC). For 1 month, providers completed a survey for each anesthetic rendered identifying type and quantity of consumables used. The mean cost of each type of anesthetic was identified. Analysis of variance was conducted using SPSS (version 7.5.1) to compare the mean costs of the three groups. Of 936 anesthetics performed, 536 surveys were returned (57%). The breakdown by type was GETA, 60% (N = 319); regional, 35% (N = 189); and MAC, 5% (N = 28). The mean cost per case type was GETA, $61.74; regional, $34.99; and MAC, $26.27. The cost of rendering a GETA was significantly greater (p < 0.0005) than that of either regional or MAC. Clinical practice guidelines were established to address areas in which cost savings could be realized and were provided to all anesthesia practitioners to assist in providing the safest and most cost-effective method of rendering an anesthetic.
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Affiliation(s)
- D M Brooks
- Navy Nurse Corps Anesthesia Program, Bethesda, MD, USA
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22
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Dittmer U, Brooks DM, Hasenkrug KJ. Requirement for multiple lymphocyte subsets in protection by a live attenuated vaccine against retroviral infection. Nat Med 1999; 5:189-93. [PMID: 9930867 DOI: 10.1038/5550] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Infection by live attenuated retroviruses provides excellent protection from challenge with pathogenic viruses in several animal models, but little is known about which immune effectors are necessary for protection. We examined this using adoptive transfer experiments in the Friend virus mouse model. Transfers of immune spleen cells into naive mice conferred complete protection, and transfers of purified lymphocyte subsets demonstrated that this effect required complex immune responses involving CD4+ and CD8+ T cells and also B cells. In addition, passive immunization experiments demonstrated that antibodies alone reduced virus loads but did not prevent infection. These findings may have implications for retroviral vaccine design in general.
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Affiliation(s)
- U Dittmer
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana 59840, USA
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23
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Barker LP, Brooks DM, Small PL. The identification of Mycobacterium marinum genes differentially expressed in macrophage phagosomes using promoter fusions to green fluorescent protein. Mol Microbiol 1998; 29:1167-77. [PMID: 9767585 DOI: 10.1046/j.1365-2958.1998.00996.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mycobacterium marinum, like Mycobacterium tuberculosis, is a slow-growing pathogenic mycobacteria that is able to survive and replicate in macrophages. Using the promoter-capture vector pFPV27, we have constructed a library of 200-1000 bp fragments of M. marinum genomic DNA inserted upstream of a promoterless green fluorescent protein (GFP) gene. Only those plasmids that contain an active promoter will express GFP. Macrophages were infected with this fusion library, and phagosomes containing fluorescent bacteria were isolated. Promoter constructs that were more active intracellularly were isolated with a fluorescence-activated cell sorter, and inserts were partially sequenced. The promoter fusions expressed intracellularly exhibited homology to mycobacterial genes encoding, among others, membrane proteins and biosynthetic enzymes. Intracellular expression of GFP was 2-20 times that of the same clones grown in media. Several promoter constructs were transformed into Mycobacterium smegmatis, Mycobacterium bovis BCG and Mycobacterium tuberculosis. These constructs were positive for GFP expression in all mycobacterial strains tested. Sorting fluorescent bacteria in phagosomes circumvents the problem of isolating a single clone from macrophages, which may contain a mixed bacterial population. This method has enabled us to isolate 12 M. marinum clones that contain promoter constructs differentially expressed in the macrophage.
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Affiliation(s)
- L P Barker
- Microscopy Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA.
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24
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Abstract
Several immunological epitopes are known to be located within the Friend murine leukemia virus (F-MuLV) envelope protein, but their relative contributions to protection from Friend virus-induced disease are not known. To determine how expression of various immunological determinants affected protection, mice were immunized with recombinant vaccinia viruses expressing different portions of the F-MuLV envelope protein, and they were then challenged with a lethal dose of Friend virus complex. The disease parameters that were followed in the mice were early viremia, early splenomegaly, and late splenomegaly. Both the N-terminal and C-terminal portions of the F-MuLV gp70 were found to protect against late splenomegaly, the primary clinical sign associated with virus-induced erythroleukemia. However, neither region alone protected against early splenomegaly and early viremia, indicating poor immunological control over early virus replication and spread through the spleen and blood. In contrast, mice immunized with a vaccine expressing the entire F-MuLV envelope protein were protected against all three disease parameters. The results indicated that expression of multiple immunological determinants including both T-helper and B cell epitopes was necessary for full protection.
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Affiliation(s)
- K J Hasenkrug
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institute of Health, 903 South 4th Street, Hamilton, Montana, 59840, USA
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25
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Abstract
Live-attenuated retroviruses have been shown to be effective retroviral vaccines, but currently little is known regarding the mechanisms of protection. In the present studies, we used Friend virus as a model to analyze characteristics of a live-attenuated vaccine in protection against virus-induced disease. Highly susceptible mice were immunized with nonpathogenic Friend murine leukemia helper virus (F-MuLV), which replicates poorly in adult mice. Further attenuation of the vaccine virus was achieved by crossing the Fv-1 genetic resistance barrier. The minimum dose of vaccine virus required to protect 100% of the mice against challenge with pathogenic Friend virus complex was determined to be 10(3) focus-forming units of attenuated virus. Live vaccine virus was necessary for induction of immunity, since inactivated F-MuLV did not induce protection. To determine whether immune cells mediated protection, spleen cells from vaccinated donor mice were adoptively transferred into syngeneic recipients. The results indicated that immune mechanisms rather than viral interference mediated protection.
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Affiliation(s)
- U Dittmer
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840, USA.
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26
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Abstract
Reactivations of persistent viral infections pose a significant medical problem in immunocompromised cancer, transplant, and AIDS patients, yet little is known about how persistent viral infections are immunologically controlled. Here we describe a mouse model for investigating the role of the immune response in controlling a persistent retroviral infection. We demonstrate that, following recovery from acute Friend virus infection, a small number of B cells evade immunological destruction and harbor persistent virus. In vivo depletions of T-cell subsets in persistently infected mice revealed a critical role for CD4(+) T cells in controlling virus replication, spread to the erythroid lineage, and induction of erythroleukemia. The CD4(+) T-cell effect was independent of CD8(+) T cells and in some cases was also independent of virus-neutralizing antibody responses. Thus, the CD4(+) T cells may have had a direct antiviral effect. These results may have relevance for human immunodeficiency virus (HIV) infections where loss of CD4(+) T cells is associated with an increase in HIV replication, reactivation of persistent viruses, and a high incidence of virus-associated cancers.
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Affiliation(s)
- K J Hasenkrug
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840, USA.
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27
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Dorward DW, Fischer ER, Brooks DM. Invasion and cytopathic killing of human lymphocytes by spirochetes causing Lyme disease. Clin Infect Dis 1997; 25 Suppl 1:S2-8. [PMID: 9233657 DOI: 10.1086/516169] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Lyme disease is a persistent low-density spirochetosis caused by Borrelia burgdorferi sensu lato. Although spirochetes causing Lyme disease are highly immunogenic in experimental models, the onset of specific antibody responses to infection is often delayed or undetectable in some patients. The properties and mechanisms mediating such immune avoidance remain obscure. To examine the nature and consequences of interactions between Lyme disease spirochetes and immune effector cells, we coincubated B. burgdorferi with primary and cultured human leukocytes. We found that B. burgdorferi actively attaches to, invades, and kills human B and T lymphocytes. Significant killing began within 1 hour of mixing. Cytopathic effects varied with respect to host cell lineage and the species, viability, and degree of attenuation of the spirochetes. Both spirochetal virulence and lymphocytic susceptibility could be phenotypically selected, thus indicating that both bacterial and host cell factors contribute to such interactions. These results suggest that invasion and lysis of lymphocytes may constitute previously unrecognized factors in Lyme disease and bacterial pathogenesis.
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Affiliation(s)
- D W Dorward
- National Institute of Allergy and Infectious Diseases, Rocky Mountain Laboratories, Hamilton, Montana 59840, USA
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28
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Waugh RE, McKenney JB, Bauserman RG, Brooks DM, Valeri CR, Snyder LM. Surface area and volume changes during maturation of reticulocytes in the circulation of the baboon. J Lab Clin Med 1997; 129:527-35. [PMID: 9142049 DOI: 10.1016/s0022-2143(97)90007-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Changes in the surface area and volume of reticulocytes were measured in vivo during late stage maturation. Baboons were treated with erythropoietin to produce mild reticulocytosis. Reticulocyte-rich cohorts of cells were obtained from whole blood by density gradient centrifugation. The cohorts were labeled with biotin, reinfused into the animal, and recovered from whole blood samples by panning on avidin supports. Changes in the surface area, volume, and membrane deformability were measured using micropipettes during the 2 to 6 weeks subsequent to reinfusion. For the entire cohort, the membrane area decreased by 10% to 15% and the cell volume decreased by approximately 8.5%, mostly within 24 hours after reinfusion. Estimates of the cellular dimensions of the reticulocyte subpopulation within this cohort indicated larger reductions in the mean cell area (12% to 30%) and mean cell volume (approximately 15%) of the reticulocytes themselves. Two weeks after reinfusion, the distribution of cell size for the cohort was indistinguishable from that of whole blood. There was evidence of slightly elevated membrane shear rigidity in some reticulocytes before reinfusion, but this slight increase disappeared within 24 hours after reinfusion. These are the first direct measurements of changes in the membrane physical properties of an identifiable cohort of reticulocytes as they mature in vivo.
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Affiliation(s)
- R E Waugh
- Department of Biophysics, University of Rochester School of Medicine and Dentistry, New York 14642, USA
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29
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Tumas DB, Spangrude GJ, Brooks DM, Williams CD, Chesebro B. High-frequency cell surface expression of a foreign protein in murine hematopoietic stem cells using a new retroviral vector. Blood 1996; 87:509-17. [PMID: 8555472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A retroviral vector (pSFF) derived from murine Friend spleen focus forming virus was used to transduce murine hematopoietic stem cells and express a cell surface marker protein, mutated murine prion protein, in vitro and in vivo after transplantation. To enhance retroviral vector integration in bone marrow cells, mice were treated with 5-fluorouracil (5-FU) to increase stem cell mitotic activity, which peaked on day 8 post-5-FU. The infectivity titer of the vector, pSFF-mPrP-3F4, was determined by a novel assay in which antigen-positive foci of infected cells were detected after replication and spread of the vector in cultures of mixed packaging cell lines. Infection of Sca-1+/Lineageneg-low cells with pSFF-mPrP-3F4 resulted in marker protein expression in 40% of the progeny cells after 7 days of culture. Transplantation of marrow cells or sorted Sca-1+/Lineageneg-low cells transduced with vector resulted in 3F4-positive mPrP expression in 11% to 37% of donor-derived peripheral blood leukocytes at 2 weeks. Though the percentage of 3F4-positive blood cells gradually declined, at 28 weeks 23% of recipient mice still maintained expression of the marker gene. Expression was observed in lymphoid, myeloid, and erythroid lineages and was detected in Sca-1+/Lineageneg-low marrow cells. The multilineage, high-frequency expression observed suggests that pSFF may be useful in gene therapy directed at hematopoietic stem cells and their differentiated progeny.
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Affiliation(s)
- D B Tumas
- Laboratories of Persistent Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, MT 59840, USA
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30
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Abstract
Friend murine leukemia virus is a retrovirus complex that induces rapid erythroleukemia and immunosuppression in susceptible strains of adult mice. Using this model, we directly examined the T-cell subsets required for a protective retrovirus vaccine. Paradoxically, recovery in mice immunized with a chimeric envelope containing only T-helper (TH) and B-cell epitopes was dependent on CD8+ T cells as well as CD4+ T cells despite the fact that the vaccine contained no CD8+ cytolytic T-lymphocyte (CTL) epitopes. However, the requirement for CD8+ T cells was overcome by inclusion of additional TH and B-cell epitopes in the immunizing protein. These additional epitopes primed for more rapid production of virus-neutralizing antibody which appeared to limit virus spread sufficiently to protect even in the absence of CD8+ T cells. Inclusion of an immunodominant CTL epitope in the vaccine was not sufficient to overcome dependence on CD4+ T cells. These data suggest that TH priming is more critical for retrovirus immunity than CTL priming.
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Affiliation(s)
- K J Hasenkrug
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, Hamilton, Montana 59840, USA
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31
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Hasenkrug KJ, Brooks DM, Chesebro B. Passive immunotherapy for retroviral disease: influence of major histocompatibility complex type and T-cell responsiveness. Proc Natl Acad Sci U S A 1995; 92:10492-5. [PMID: 7479826 PMCID: PMC40637 DOI: 10.1073/pnas.92.23.10492] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Administration of virus-specific antibodies is known to be an effective early treatment for some viral infections. Such immunotherapy probably acts by antibody-mediated neutralization of viral infectivity and is often thought to function independently of T-cell-mediated immune responses. In the present experiments, we studied passive antibody therapy using Friend murine leukemia virus complex as a model for an immunosuppressive retroviral disease in adult mice. The results showed that antibody therapy could induce recovery from a well-established retroviral infection. However, the success of therapy was dependent on the presence of both CD4+ and CD8+ T lymphocytes. Thus, cell-mediated responses were required for recovery from infection even in the presence of therapeutic levels of antibody. The major histocompatibility type of the mice was also an important factor determining the relative success of antibody therapy in this system, but it was less critical for low-dose than for high-dose infections. Our results imply that limited T-cell responsiveness as dictated by major histocompatibility genes and/or stage of disease may have contributed to previous immunotherapy failures in AIDS patients. Possible strategies to improve the efficacy of future therapies are discussed.
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Affiliation(s)
- K J Hasenkrug
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA
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Affiliation(s)
- J E Jackson
- Department of Diagnostic Radiology, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK
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33
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Spangrude GJ, Brooks DM, Tumas DB. Long-term repopulation of irradiated mice with limiting numbers of purified hematopoietic stem cells: in vivo expansion of stem cell phenotype but not function. Blood 1995; 85:1006-16. [PMID: 7849289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Hematopoietic stem cells were isolated from normal adult mouse bone marrow based on surface antigen expression (Thy-1.1(low)Lin(neg)Ly-6A/E+) and further selected for low retention of rhodamine 123. This population of cells (Rh-123low) could mediate radioprotection and long-term (greater than 12 months) repopulation after transplantation of as few as 25 cells. Transfer of five genetically marked Rh-123low cells in the presence of 10(5) normal bone marrow cells resulted in reconstitution of peripheral blood by greater than 10% donor cells in 64% (30 of 47) of recipient mice. Of 46 animals surviving after 24 weeks, 10 had over 50% donor-derived cells in peripheral blood. Two general patterns of long-term reconstitution were observed: one in which many donor-derived cells were observed 5 to 6 weeks after reconstitution and another in which donor-derived cells were rare initially but expanded with time. This result suggests that two classes of long-term repopulating hematopoietic stem cells exist, differing in their ability to function early in the course of transplantation. Alternatively, distinct anatomic sites of engraftment may dictate these two outcomes from a single type of cell. As an approach to measure the extent of self-renewal by the injected cells, recipients of five or 200 stem cells were killed 8 to 13 months after the transplants, and Thy-1.1(low)Lin(neg)Ly-6A/E+ progeny of the original injected cells were isolated for a second transplant. While a numerical expansion of cells expressing the cell surface phenotype of stem cells was observed, along with activity in the colony-forming unit-spleen assay, the expanded cells were vastly inferior in radioprotection and long-term reconstitution assays when compared with cells freshly isolated from normal animals. This result demonstrates that in stem cell expansion experiments, cell surface antigen expression is not an appropriate indicator of stem cell function.
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Affiliation(s)
- G J Spangrude
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT
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Hasenkrug KJ, Sprangrude GJ, Nishio J, Brooks DM, Chesebro B. Recovery from Friend disease in mice with reduced major histocompatibility complex class I expression. J Virol 1994; 68:2059-64. [PMID: 8138991 PMCID: PMC236679 DOI: 10.1128/jvi.68.4.2059-2064.1994] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Mice homozygous for the b allele of the MHC gene, H-2D, have a high incidence of recovery from Friend virus infections, while mice heterozygous for the b allele at H-2D have a very low incidence of recovery. Previous experiments indicated that the low recovery rates associated with heterozygosity at H-2D might be related to a gene dosage effect requiring the expression of two H-2Db alleles for high recovery. We investigated the effects of reduced H-2Db expression on recovery from Friend disease by using H-2b homozygous mice carrying a single beta 2-microglobulin gene disruption. These mice had reductions in cell surface H-2Db expression comparable to those of H-2Da/b heterozygotes. Numerous cell types with various levels of H-2Db expression were examined, and in each case, the expression levels in the beta 2-microglobulin mutants closely reflected those observed in the H-2Da/b heterozygotes. We found, however, that reduced expression did not affect recovery from Friend disease, indicating that heterozygous levels of H-2Db expression are sufficient for the high-recovery phenotype previously associated only with H-2Db homozygotes.
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Affiliation(s)
- K J Hasenkrug
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840
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35
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Spangrude GJ, Brooks DM. Mouse strain variability in the expression of the hematopoietic stem cell antigen Ly-6A/E by bone marrow cells. Blood 1993; 82:3327-32. [PMID: 8241503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The cell surface molecule Ly-6A/E provides a convenient marker for primitive stem cells in the hematopoietic tissues of both fetal and adult mice. However, previous studies have shown that Ly-6A/E expression by lymphocytes is variable depending on the haplotype of the Ly-6 locus. Therefore, strain-specific variation in Ly-6A/E expression by bone marrow (BM) cells was investigated. The results show that Ly-6a mice have, on average, 50% of the number of BM cells expressing Ly-6A/E relative to that for Ly-6b mice. Furthermore, among the 5% of BM cells that do not express antigens characteristic of mature T, B, myeloid, or erythroid lineages, which include the primitive hematopoietic stem cell compartment, Ly-6a mice have, on average, more than fivefold fewer Ly-6A/E+ cells relative to that for Ly-6b mice. Isolation of Ly-6A/E- and Ly-6A/E+ cells from mice of both haplotypes showed that, whereas 99% of the marrow repopulating activity (MRA) of C57BL/Ka (Ly-6b) mice could be recovered in the Ly-6A/E+ fraction, only about 25% of the MRA of BALB/c (Ly-6a) was recoverable in the same population. On a per-cell basis, the Ly-6A/E+ cells that were isolated from BALB/c mice were essentially equivalent in MRA to those isolated from C57BL/Ka mice. Thus, whereas a large percentage of the hematopoietic stem cells of Ly-6a mice do not express the Ly-6A/E molecule, the antigen may be used to isolate a subset of stem cells from these mice. These results show that hematopoietic stem cell phenotype can vary between mouse strains and imply that caution should be exercised in the identification of human stem cell antigens such as CD34, because a similar variability may occur between individual humans. To further explore the influence of Ly-6 haplotype on Ly-6A/E expression by specific cell subsets, lymph-node lymphocytes from a panel of mouse strains were analyzed by multiparameter flow cytometry for correlated expression of Ly-6A/E, CD4, and CD8. All Ly-6a strains examined had less than 20% Ly-6A/E+ cells, and those cells were predominantly CD8+ T lymphocytes. In contrast, the Ly-6b strains had greater than 30% Ly-6A/E+ cells, and those cells included CD4+, CD8+, and B lymphocytes.
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Affiliation(s)
- G J Spangrude
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840
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36
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Spangrude GJ, Brooks DM. Phenotypic analysis of mouse hematopoietic stem cells shows a Thy-1-negative subset. Blood 1992; 80:1957-64. [PMID: 1356513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2023] Open
Abstract
Mouse hematopoietic stem cells can be identified and enriched from populations of normal bone marrow cells by immunofluorescent labeling of cell surface molecules followed by flow cytometric separation. We show here that the majority of hematopoietic stem cell activity, as defined by long-term competitive repopulation of irradiated animals and by a secondary transplant assay for spleen colony-forming units (CFU-S), could be localized in Ly-6b haplotype mice to a fraction of bone marrow cells that expresses the Ly-6A/E (Sca-1) molecule. Further, an analysis of hematopoietic stem cell activity in bone marrow of mouse strains expressing the Thy-1.1 allele indicated that the vast majority of activity was included in the Thy-1low population. In contrast, hematopoietic stem cell activity found in the bone marrow of Thy-1.2 genotype mouse strains was recovered in both the Thy-1neg and the Thy-1low populations. However, similar to Thy-1.1 strains, most activity was localized to the Ly-6A/E+ population of cells. The difference in Thy-1 phenotype of hematopoietic stem cell activity apparent between Thy-1.1- and Thy-1.2-expressing mouse strains was not caused by differences in the staining intensity of monoclonal antibodies (MoAbs) specific for the Thy-1 alleles. Furthermore, an antiframework MoAb that stains both alleles of Thy-1 separated hematopoietic stem cell activity from mice expressing the two alleles in the same manner as did allele-specific MoAb. The results of this study show that Thy-1 expression is not an invariant characteristic of mouse hematopoietic stem cells, and that mice expressing the Thy-1.1 allele are unique in that hematopoietic stem cell activity is found exclusively in the Thy-1low population.
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Affiliation(s)
- G J Spangrude
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840
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37
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Abstract
Prediction tree techniques are employed in the analysis of data from 555 patients admitted to the Medical College of Virginia hospitals with severe head injuries. Twenty-three prognostic indicators are examined to predict the distribution of 12-month outcomes among the five Glasgow Outcome Scale categories. A tree diagram, illustrating the prognostic pattern, provides critical threshold levels that split the patients into subgroups with varying degrees of risk. It is a visually useful way to look at the prognosis of head-injured patients. In previous analyses addressing this prediction problem, the same set of prognostic factors (age, motor score, and pupillary response) was used for all patients. These approaches might be considered inflexible because more informative prediction may be achieved by somewhat different combinations of factors for different patients. Tree analysis reveals that the pattern of important prognostic factors differs among various patient subgroups, although the three previously mentioned factors are still of primary importance. For example, it is noted that information concerning intracerebral lesions is useful in predicting outcome for certain patients. The overall predictive accuracy of the tree technique for these data is 77.7%, which is somewhat higher than that obtained via standard prediction methods. The predictive accuracy is highest among patients who have a good recovery or die; it is lower for patients having intermediate outcomes.
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Affiliation(s)
- S C Choi
- Department of Biostatistics, Medical College of Virginia, Virginia Commonwealth University, Richmond
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38
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Melvin DB, Brooks DM, Taliano RJ. Electric power induction through an isolated intestinal pouch. ASAIO Trans 1991; 37:M203-4. [PMID: 1751111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A new transintegumental power transformer uses the walls of an isolated intestinal pouch to separate primary and secondary coils. It may surpass transcutaneous devices in heat dissipation potential and in comfort. It was acutely tested in 13 dogs. Corrections in geometry and insulation were suggested by the nine initial trials. In the remaining four animals, up to 14.1 W were delivered, incrementing over 90 to 395 min. Three pouch and two remote thermistors recorded temperature (T) at 10 min intervals. Thirty sets of data were taken at 4 W or less (Group A), 31 at 4-8 W (Group B), and 16 at more than 8 W (Group C). T elevations above reference drift were 0.096 + 0.062 degrees C, 0.468 + 0.234 degrees C, and 0.876 + 0.156 degrees C for groups A, B, and C, respectively. These were significant by t-tests (p less than 0.001 for Group A vs. B; p less than 0.05 for Group B vs. C). The concept appears to be feasible, and longer term implantation trials seem justified.
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Affiliation(s)
- D B Melvin
- University of Cincinnati, College of Medicine, Department of Surgery, Ohio
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39
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Braswell C, Decuir A, Brooks DM. A survey of clinical training in music therapy: degree of compliance with NAMT guidelines. J Music Ther 1986; 22:73-86. [PMID: 10271938 DOI: 10.1093/jmt/22.2.73] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
This study compared the experiences and responsibilities of music therapy interns with requirements outlined in the Guidelines for Establishing and Maintaining Music Therapy Clinical Training Programs (National Association for Music Therapy, Inc., 1983). Subjects were 134 music therapy clinical training directors and 75 music therapy interns. Results from the intern survey indicated that over 80% of the interns were more than satisfied with their clinical training experiences. However, the data revealed several areas of concern. First, 75% of the directors and 92% of the responding interns were female; this response suggests that music therapy is not recognized as a viable career choice among male music majors. In addition, 22% of the responding clinical training facilities were not affiliated with the closest NAMT-approved college or university; reported range between these facilities and the nearest university was 5 to 1,500 miles, with a mean of 392 miles. The authors concluded that the affiliate process is often meaningless. While the Guidelines require training in "Administrative skills, i.e., budgeting, program proposals, organizational structures," nearly 63% of intern respondents had not received such training. The authors recommend that the Guidelines be rewritten and professionally printed, that interns and clinical training directors be required to complete annual questionnaires, and that the affiliation between clinical training facility and academic institution be strengthened.
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40
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Abstract
We compared the homologous amino acid sequences of hevein and each of the four domains (A, B, C, and D) of wheat germ agglutinin and used them to construct a pseudophylogenetic tree relating these sequences to a hypothetical common ancestor sequence. In the crystal structure of the wheat germ agglutinin dimer, six pseudo-two-fold rotational symmetry axes have previously been located in addition to the true twofold axis. Four of these relate two nonidentical domains to each other in each of the four possible pairs constituting the sugar-binding sites (A1D2, A2D1, B1C2, and B2C1). The remaining two relate contiguous unique pairs of sugar-binding sites to each other (A1D2 to B1C2, and A2D1 to B2C1). These latter two sets of pairs are related to each other by the true twofold axis. Side chains that mediate sugar binding in the interfaces of each of the four pairs were found to be largely conserved. The sequence homology, taken together with these pseudo-symmetry elements in the dimer structure, suggests a pathway for the evolution of the four-domain molecule from a single-domain dimer that can be correlated with simultaneous development of the saccharide-binding sites.
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41
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Braswell C, Brooks DM, Decuir A, Humphrey T, Jacobs KW, Sutton K. Development and implementation of a music/activity therapy intake assessment for psychiatric patients. Part I: initial standardization procedures on data from university students. J Music Ther 1984; 20:88-100. [PMID: 10262389 DOI: 10.1093/jmt/20.2.88] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The stimulus for the Music/Activity Therapy Intake Assessment was a recent publication by the Joint Commission on Accreditation of Hospitals requiring for activity services, "assessment of the patient's needs, interests, life experiences, capacities, and deficiencies" (1981, p. 126). The Assessment was written in the spring of 1982 and contains four sections: Activity Preference, Organizational involvement, Attitude Survey, and Post-Interview Observations. The purpose of the present study was to investigate the psychometric properties of the Attitude Survey. The Attitude Survey was administered to 214 university students enrolled in three areas of study: human science, performance, and liberal arts. Results show that each of the three scales in the Survey is internally consistent (.63 to .74), that each scale measures a single large dimension, and that two of the three scales significantly discriminate between groups of students (p less than .05). The authors conclude that the Attitude Survey possesses adequate psychometric properties to justify its continued use as part of the Music/Activity Intake Assessment.
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42
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Abstract
In view of several case reports of relief of various neuralgias by propranolo, a double-blind cross-over trial using this drug was conducted in 10 patients with severe persistent pain and paraesthesiae following upper limb peripheral nerve injuries. The patients received up to 240 mg of propranolol per day. Only one patient reported pain relief, but this patient withdrew from the trial. An open trial of propranolol was conducted in 6 other patients with a variety of peripheral nerve lesions. Of these, neuroma tenderness was transiently reduced in one patient and the hyperaesthesia of a painful scar was relieved in another. Routine use of propranolol in such patients cannot be recommended.
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Affiliation(s)
- J W Scadding
- Royal National Orthopaedic Hospital, Great Portland Street, London W1 and Cerebral Functions Research Group, Department of Anatomy, University College London, Cower St., London WC1 Great Britain
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43
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Abstract
It was hypothesized that the large variance in low achievers' self-portraits may be related to frustration and symbolic acting out. 29 low achievers in Reading and Mathematics were given the Describe Your School inventory. Subjects below the median drew pictures which were taller than pictures drawn by subjects above the median score. It was concluded that frustation must be considered when using height of drawing to analyze low achievers' self-portraits.
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Abstract
Nerve pedicle grafts in the upper limb were performed on nine patients with Volkmann's Ischaemia. Long-term follow-up of three cases has shown that the results of this operation are successful. Sensory and motor recovery of the median nerve occurs and consequently useful hand function is regained. Since Volkmann's Ischaemic contracture is not rare in developing countries, this operation should be the treatment of choice when the median and ulnar nerves have been damaged beyond hope of recovery.
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45
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Brooks DM. Problems of restoration of tendon movements after repair and grafts. Proc R Soc Med 1970; 63:67-8. [PMID: 5417784 PMCID: PMC1810953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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46
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