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Nguyen A, Brown NJ, Gendreau J, Nguyen BA, Pennington Z, Zhang A, Harris MH, Chakravarti S, Douse DM, Van Gompel JJ. The association of thromboembolic complications and the use of tranexamic acid during resection of intracranial meningiomas: systematic review and meta-analysis of randomized controlled trials. J Neurosurg 2024; 140:1008-1018. [PMID: 37856372 DOI: 10.3171/2023.7.jns23849] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 07/24/2023] [Indexed: 10/21/2023]
Abstract
OBJECTIVE Antifibrinolytics, such as tranexamic acid (TXA), have been shown to decrease intraoperative blood loss across multiple surgical disciplines. However, they carry the theoretical risk of thromboembolic events secondary to induced hypercoagulability. Therefore, the aim of this study was to systematically review the available literature and perform a meta-analysis on the use of TXA in meningioma resection to assess thromboembolic risks. METHODS The PubMed, Web of Science, and Google Scholar databases were reviewed for all randomized controlled trials presenting primary data on TXA use during resection of intracranial meningiomas. Data were gathered on operative duration, venous thromboembolic complications, deep venous thrombosis, use of allogeneic blood transfusion, estimated blood loss (EBL), and postoperative hemoglobin. Patients who received TXA were compared with controls who did not receive TXA intraoperatively using random-effects models. RESULTS A total of 508 unique articles were identified, of which 493 underwent full-text review. Ultimately, 6 studies with 381 total patients (190 receiving TXA) were included in the final analysis. All 6 trials were randomized, blinded, and placebo controlled with a TXA administration rate of a 20-mg/kg load followed by a 1-mg/kg/hr infusion. All studies were performed in lower-middle-income countries. There were no reported instances of venous thromboembolism (VTE) in the TXA and non-TXA cohorts. Patients receiving TXA exhibited fewer allogeneic transfusions (21.5% vs 41.6% [OR 0.26, 95% CI 0.09-0.77], p = 0.02) and lower EBL (MD -282.48 mL [95% CI -367.77 to -197.20 mL], p < 0.001) compared with patients who did not receive TXA, and they also had lower rates of perioperative complications (10.7% vs 19.9% [OR 0.47, 95% CI 0.2-0.95], p = 0.04). CONCLUSIONS Current literature suggests that TXA is not associated with increased risk for VTE when administered during resection of intracranial meningioma. TXA appears to decrease intraoperative blood loss and allogeneic transfusion requirements during meningioma resection and thus may improve the safety of surgical management of this pathology.
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Affiliation(s)
- Andrew Nguyen
- 1Department of Neurological Surgery, University of Florida School of Medicine, Gainesville, Florida
| | - Nolan J Brown
- 2Department of Neurological Surgery, University of California, Irvine, Orange, California
| | - Julian Gendreau
- 3Johns Hopkins Whiting School of Engineering, Baltimore, Maryland
| | - Brandon A Nguyen
- 4Department of Neurologic Surgery, Mayo Clinic Alix School of Medicine, Scottsdale, Arizona
| | | | - Angie Zhang
- 2Department of Neurological Surgery, University of California, Irvine, Orange, California
| | - Mark H Harris
- 2Department of Neurological Surgery, University of California, Irvine, Orange, California
| | | | - Dontre' M Douse
- 6Otolaryngology, Head and Neck Surgery, Mayo Clinic, Rochester, Minnesota
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McGrath M, Sarhadi K, Harris MH, Baird-Daniel E, Greil M, Barrios-Anderson A, Robinson E, Fong CT, Walters AM, Lele AV, Wahlster S, Bonow R. Utility of Routine Surveillance Head Computed Tomography After Receiving Therapeutic Anticoagulation in Patients with Acute Traumatic Intracranial Hemorrhage. World Neurosurg 2024:S1878-8750(24)00416-9. [PMID: 38490443 DOI: 10.1016/j.wneu.2024.03.031] [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] [Received: 10/26/2023] [Revised: 03/06/2024] [Accepted: 03/07/2024] [Indexed: 03/17/2024]
Abstract
INTRODUCTION Patients with traumatic intracranial hemorrhage (tICH) are at increased risk of venous thromboembolism and may require anticoagulation. We evaluated the utility of surveillance computed tomography (CT) in patients with tICH who required therapeutic anticoagulation. METHODS This single institution, retrospective study included adult patients with tICH who required anticoagulation within 4 weeks and had a surveillance head CT within 24 hours of reaching therapeutic anticoagulation levels. The primary outcome was hematoma expansion (HE) detected by the surveillance CT. Secondary outcomes included 1) changes in management in patients with HE on the surveillance head CT, 2) HE in the absence of clinical changes, and 3) mortality due to HE. We also compared mortality between patients who did and did not have a surveillance CT. RESULTS Of 175 patients, 5 (2.9%) were found to have HE. Most (n = 4, 80%) had changes in management including anticoagulation discontinuation (n = 4), reversal (n = 1), and operative management (n = 1). Two patients developed symptoms or exam changes prior to the head CT. Of the 3 patients (1.7%) without preceding exam changes, each had only very minor HE and did not require operative management. No patient experienced mortality directly attributed to HE. There was no difference in mortality between patients who did and those who did not have a surveillance scan. CONCLUSIONS Our findings suggest that most patients with tICH who are started on anticoagulation could be followed clinically, and providers may reserve CT imaging for patients with changes in exam/symptoms or those who have a poor clinical examination to follow.
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Affiliation(s)
- Margaret McGrath
- Department of Neurological Surgery, University of Washington, Seattle, Washington.
| | - Kasra Sarhadi
- Department of Neurology, University of Washington, Seattle, Washington
| | - Mark H Harris
- School of Medicine, University of California, Irvine, California
| | - Eliza Baird-Daniel
- Department of Neurological Surgery, University of Washington, Seattle, Washington
| | - Madeline Greil
- Department of Neurological Surgery, University of Washington, Seattle, Washington
| | | | - Ellen Robinson
- Quality Improvement, Harborview Medical Center, Seattle, Washington
| | - Christine T Fong
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington
| | - Andrew M Walters
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington
| | - Abhijit V Lele
- Department of Neurological Surgery, University of Washington, Seattle, Washington; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington; Harborview Injury Prevention Research Center, University of Washington, Seattle, Washington
| | - Sarah Wahlster
- Department of Neurological Surgery, University of Washington, Seattle, Washington; Department of Neurology, University of Washington, Seattle, Washington; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington
| | - Robert Bonow
- Department of Neurological Surgery, University of Washington, Seattle, Washington; Harborview Injury Prevention Research Center, University of Washington, Seattle, Washington
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Miles NL, Abedini NC, Harris MH, Engelberg RA, Kross EK, Creutzfeldt CJ. Goals-of-Care Conversations After Stroke Survival. Stroke 2024; 55:e44-e45. [PMID: 38189121 PMCID: PMC10922777 DOI: 10.1161/strokeaha.123.046119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Affiliation(s)
- Nancy L. Miles
- University of Washington School of Medicine, Seattle, WA
| | - Nauzley C. Abedini
- University of Washington School of Medicine, Seattle, WA
- Cambia Palliative Care Center of Excellence at UW Medicine, Seattle WA
| | - Mark H. Harris
- University of California, Irvine School of Medicine, Irvine, CA
| | - Ruth A. Engelberg
- Cambia Palliative Care Center of Excellence at UW Medicine, Seattle WA
- University of Washington Department of Medicine, Seattle, WA
| | - Erin K. Kross
- Cambia Palliative Care Center of Excellence at UW Medicine, Seattle WA
- University of Washington Department of Medicine, Seattle, WA
| | - Claire J. Creutzfeldt
- Cambia Palliative Care Center of Excellence at UW Medicine, Seattle WA
- University of Washington Department of Neurology, Seattle, WA
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Picton B, Huynh A, Brown NJ, Beyer RS, Lew R, Hatter MJ, Andalib S, Harris MH, Hashmi S. Contemporary Trends in the Orthopaedic Surgery Residency Match and the Effects of COVID-19. JB JS Open Access 2024; 9:e23.00066. [PMID: 38188191 PMCID: PMC10758528 DOI: 10.2106/jbjs.oa.23.00066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2024] Open
Abstract
Objective We aimed to elucidate associations between geographic location, size, and ranking of medical schools that orthopaedic surgery residents graduate from and the residencies that they match both pre-COVID-19 and post-COVID-19 pandemic by examining the 2017 to 2022 orthopaedic surgery residency cohorts. Methods Demographics were extracted using Doximity Residency Navigator platform, the 2021 US News and World Report, and program websites. Medical schools were classified as large if they had >613 medical students. Postgraduate year 1 (PGY-1) (2021 match) and PGY-2 (2022 match) residents were classified as the COVID-19 cohort. Location was categorized as Northeast, Midwest, South, and West. Chi-square tests, Cohen's H value, and descriptive statistics were used for analysis with statistical significance set at p <0.05. Results Four thousand two hundred forty-three residents from 160 accredited US orthopaedic residency programs (78.4%) were included. Northeastern applicants were most likely to match in the same region (p <0.01), and southern applicants were most likely to match at their home program (p <0.001). Applicants affected by the COVID-19 pandemic did not differ from their predecessors with regards to matching to the same region (p = 0.637) or home program (p = 0.489). Applicants from public medical schools were more likely to match in the same region and at their home program (p <0.001), whereas those from private medical schools were more likely to match at top-ranked residencies (p <0.001). Students from both top 25- and top 50-ranked medical schools were more likely to match at their home program (p <0.01) and attend top 20-ranked residency programs (p <0.0001). Conclusion These results demonstrate significant associations between matched residencies and attended medical schools' geographic location, school type, and ranking. During the pandemic, geographic trends were overall unchanged, whereas residents from large or lower-ranked schools were more likely to match at home programs, and those from private or top-ranked schools were less likely to attend top residencies.
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Affiliation(s)
- Bryce Picton
- University of California, Irvine School of Medicine, Irvine, California
| | - Ashley Huynh
- University of California, Irvine School of Medicine, Irvine, California
| | - Nolan J. Brown
- Department of Neurological Surgery, University of California, Irvine, Orange, California
| | - Ryan S. Beyer
- Department of Orthopaedic Surgery, University of California, Irvine, Orange, California
| | - Ryan Lew
- University of California, Irvine School of Medicine, Irvine, California
| | - Matthew J. Hatter
- Department of Orthopaedic Surgery, University of California, Irvine, Orange, California
| | - Saman Andalib
- University of California, Irvine School of Medicine, Irvine, California
| | - Mark H. Harris
- Department of Neurological Surgery, University of California, Irvine, Orange, California
| | - Sohaib Hashmi
- Department of Orthopaedic Surgery, University of California, Irvine, Orange, California
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Shooshani T, Pooladzandi O, Nguyen A, Shipley JH, Harris MH, Hovis GEA, Barrios C. Field Measures Are All You Need: Predicting Need for Surgery in Elderly Ground-Level Fall Patients via Machine Learning. Am Surg 2023; 89:4095-4100. [PMID: 37218170 DOI: 10.1177/00031348231177917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
BACKGROUND As ground-level falls (GLFs) are a significant cause of mortality in elderly patients, field triage plays an essential role in patient outcomes. This research investigates how machine learning algorithms can supplement traditional t-tests to recognize statistically significant patterns in medical data and to aid clinical guidelines. METHODS This is a retrospective study using data from 715 GLF patients over 75 years old. We first calculated P-values for each recorded factor to determine the factor's significance in contributing to a need for surgery (P < .05 is significant). We then utilized the XGBoost machine learning method to rank contributing factors. We applied SHapley Additive exPlanations (SHAP) values to interpret the feature importance and provide clinical guidance via decision trees. RESULTS The three most significant P-values when comparing patients with and without surgery are as follows: Glasgow Coma Scale (GCS) (P < .001), no comorbidities (P < .001), and transfer-in (P = .019). The XGBoost algorithm determined that GCS and systolic blood pressure contribute most strongly. The prediction accuracy of these XGBoost results based on the test/train split was 90.3%. DISCUSSION When compared to P-values, XGBoost provides more robust, detailed results regarding the factors that suggest a need for surgery. This demonstrates the clinical applicability of machine learning algorithms. Paramedics can use resulting decision trees to inform medical decision-making in real time. XGBoost's generalizability power increases with more data and can be tuned to prospectively assist individual hospitals.
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Affiliation(s)
- Tara Shooshani
- University of California, Irvine School of Medicine, Irvine, CA, USA
| | | | - Andrew Nguyen
- University of California, Los Angeles, Los Angeles, CA, USA
| | | | - Mark H Harris
- University of California, Irvine School of Medicine, Irvine, CA, USA
| | | | - Cristobal Barrios
- University of California, Irvine School of Medicine, Irvine, CA, USA
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Huynh A, Nguyen A, Beyer RS, Harris MH, Hatter MJ, Brown NJ, de Virgilio C, Nahmias J. Fixing a Broken Clerkship Assessment Process: Reflections on Objectivity and Equity Following the USMLE Step 1 Change to Pass/Fail. Acad Med 2023; 98:769-774. [PMID: 36780667 DOI: 10.1097/acm.0000000000005168] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Clerkship grading is a core feature of evaluation for medical students' skills as physicians and is considered by most residency program directors to be an indicator of future performance and success. With the transition of the U.S. Medical Licensing Examination Step 1 score to pass/fail, there will likely be even greater reliance on clerkship grades, which raises several important issues that need to be urgently addressed. This article details the current landscape of clerkship grading and the systemic discrepancies in assessment and allocation of honors. The authors examine not only objectivity and fairness in clerkship grading but also the reliability of clerkship grading in predicting residency performance and the potential benefits and drawbacks to adoption of a pass/fail clinical clerkship grading system. In the promotion of a more fair and equitable residency selection process, there must be standardization of grading systems with consideration of explicit grading criteria, grading committees, and/or structured education of evaluators and assessors regarding implicit bias. In addition, greater adherence and enforcement of transparency in grade distributions in the Medical Student Performance Evaluation is needed. These changes have the potential to level the playing field, foster equitable comparisons, and ultimately add more fairness to the residency selection process.
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Affiliation(s)
- Ashley Huynh
- A. Huynh is a first-year medical student, University of California, Irvine, School of Medicine, Irvine, California; ORCID: https://orcid.org/0000-0002-4413-6829
| | - Andrew Nguyen
- A. Nguyen is a first-year medical student, University of Florida College of Medicine, Gainesville, Florida; ORCID: https://orcid.org/0000-0002-8131-150X
| | - Ryan S Beyer
- R.S. Beyer is a second-year medical student, University of California, Irvine, School of Medicine, Irvine, California; ORCID: https://orcid.org/0000-0002-0283-3749
| | - Mark H Harris
- M.H. Harris is a second-year medical student, University of California, Irvine, School of Medicine, Irvine, California; ORCID: https://orcid.org/0000-0002-1598-225X
| | - Matthew J Hatter
- M.J. Hatter is a second-year medical student, University of California, Irvine, School of Medicine, Irvine, California; ORCID: https://orcid.org/0000-0003-2922-6196
| | - Nolan J Brown
- N.J. Brown is a fourth-year medical student, University of California, Irvine, School of Medicine, Irvine, California; ORCID: https://orcid.org/0000-0002-6025-346X
| | - Christian de Virgilio
- C. de Virgilio is professor of surgery, Harbor-UCLA Medical Center, Torrance, California
| | - Jeffry Nahmias
- J. Nahmias is professor of trauma, burns, surgical critical care, and acute care surgery, University of California, Irvine, School of Medicine, Irvine, California; ORCID: https://orcid.org/0000-0003-0094-571X
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Hovis GEA, Harris MH, Nguyen A, Picton B, Kuo CC, Hamidi S, Brown NJ, Gendreau J, Beyer RS, Golshani K, Oh MY. Analysis of Current Neurological Surgery Residents and Prior Medical Education: Do Medical School Attributes Matter? World Neurosurg 2023; 172:e695-e700. [PMID: 36764450 DOI: 10.1016/j.wneu.2023.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 02/02/2023] [Indexed: 02/11/2023]
Abstract
BACKGROUND With the recent changes to the U.S. Medical Licensing Examination grading system, an understanding of the factors that influence the neurological surgery residency match process is crucial for residency directors. The aim of the present retrospective study was to explore the associations of medical school location, ranking, private school status, size, and presence of an American Association of Neurological Surgeons (AANS) chapter or neurological surgery interest group (NSIG) with the neurosurgery match outcomes. METHODS An enrollment list of all accredited U.S. neurosurgery residency programs was compiled on June 28, 2021. For the included residents, the residency program, degree, and previously attended medical school were retrieved. The geographic location, ranking, private school status, and size were collected for the residency programs and medical schools attended by the residents at each program. RESULTS A total of 1437 residents from 101 neurosurgery residency programs (89%) were included. Graduates from the top 25 medical schools were more likely to match into their home residency programs (P < 0.001) and highly ranked residency programs (P < 0.001). Students from larger medical schools were also more likely to match into larger (P < 0.001) and highly ranked (P < 0.001) programs than were applicants from smaller schools. Students from medical schools with an AANS chapter or NSIG were also more likely to match into top ranked programs (P < 0.001 for both). CONCLUSIONS Medical students from the top 25 medical schools, private medical schools, medical schools with an AANS chapter, and medical schools with an NSIG were more likely to match into a prestigious residency program. These findings suggest that underlying biases might be present for program directors to consider in the resident selection process.
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Affiliation(s)
- Gabrielle E A Hovis
- Department of Neurosurgery, University of California, Irvine, Orange, California, USA.
| | - Mark H Harris
- Department of Neurosurgery, University of California, Irvine, Orange, California, USA
| | - Andrew Nguyen
- Department of Neurosurgery, University of California, Irvine, Orange, California, USA
| | - Bryce Picton
- Department of Neurosurgery, University of California, Irvine, Orange, California, USA
| | - Cathleen C Kuo
- Department of Neurosurgery, The State University of New York at Buffalo, Buffalo, New York, USA
| | - Sabah Hamidi
- Department of Neurosurgery, University of California, Irvine, Orange, California, USA
| | - Nolan J Brown
- Department of Neurosurgery, University of California, Irvine, Orange, California, USA
| | - Julian Gendreau
- Department of Biomedical Engineering, Johns Hopkins Whiting School of Engineering, Baltimore, Maryland, USA
| | - Ryan S Beyer
- Department of Neurosurgery, University of California, Irvine, Orange, California, USA
| | - Kiarash Golshani
- Department of Neurosurgery, University of California, Irvine, Orange, California, USA
| | - Michael Y Oh
- Department of Neurosurgery, University of California, Irvine, Orange, California, USA
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Lip V, Grimmett L, Diaz C, Cantave J, Yang W, Harris H, Tsai HK, Church AJ, Harris MH. MYOD1 c.365G>T, p.L122R Variant Detection by Droplet Digital PCR (ddPCR). Am J Clin Pathol 2021. [DOI: 10.1093/ajcp/aqab191.240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Introduction/Objective
Rhabomyosarcomas (RMS) are a group of skeletal muscle tumors that include embryonal, alveolar, pleomorphic, spindle cell/sclerosing subtypes (SC/SRMS). Spindle cell RMS occurs in both adult and pediatric populations, and is associated with either more aggressive or better clinical outcomes respectively. A recurrent hotspot variant in MYOD1, p.L122R (NM_002478.4 c.365G>T), has been described in SC/SRMS. The classification of this diagnosis is evolving, with VGLL2 and NCOA2 fusions defining the diagnosis in young children, and MYOD1 p.L122R defining the diagnosis in older children. The MYOD1 p.L122R variant seems to be associated with more aggressive disease, and may be increasingly used in risk stratification with intensification of treatment.
Methods/Case Report
A digital droplet PCR (ddPCR) assay was used to detect the MYOD1 p.L122R in DNA samples with RMS. Patients and controls were coded as positive or negative, and tested for association with clinical features and outcome.
Results (if a Case Study enter NA)
Known-positive cohort of samples was limited by the extreme rarity of this tumor. “Known-positive” status was established by confirmation of the variant with an external clinically-validated assay. The six known positive samples were assessed by ddPCR for the presence of MYOD1 L122R. The L122R variant was detected in all six variants for a sensitivity of 100%. DNA and/or TNA obtained from known wild-type FFPE and frozen material was assessed, for a total of nine unique samples (1 synthetic, 8 patient-derived). All 9 samples were wild- type, with no positive droplets detected, for a specificity of 100%.
Conclusion
Our MYOD1 c.365G>T, p.L122R variant detection by droplet digital PCR (ddPCR) assay is a robust, reproducible, specific and sensitive method to detect the MYOD1 hotspot mutation.
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Affiliation(s)
- V Lip
- Pathology, Boston Children’s Hospital, Boston, Massachusetts, UNITED STATES
| | - L Grimmett
- Pathology, Boston Children’s Hospital, Boston, Massachusetts, UNITED STATES
| | - C Diaz
- Pathology, Boston Children’s Hospital, Boston, Massachusetts, UNITED STATES
| | - J Cantave
- Pathology, Boston Children’s Hospital, Boston, Massachusetts, UNITED STATES
| | - W Yang
- Pathology, Boston Children’s Hospital, Boston, Massachusetts, UNITED STATES
| | - H Harris
- Pathology, Boston Children’s Hospital, Boston, Massachusetts, UNITED STATES
| | - H K Tsai
- Pathology, Boston Children’s Hospital, Boston, Massachusetts, UNITED STATES
| | - A J Church
- Pathology, Boston Children’s Hospital, Boston, Massachusetts, UNITED STATES
| | - M H Harris
- Pathology, Boston Children’s Hospital, Boston, Massachusetts, UNITED STATES
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Yuh EL, Jain S, Sun X, Pisica D, Harris MH, Taylor SR, Markowitz AJ, Mukherjee P, Verheyden J, Giacino JT, Levin HS, McCrea M, Stein MB, Temkin NR, Diaz-Arrastia R, Robertson CS, Lingsma HF, Okonkwo DO, Maas AIR, Manley GT, Adeoye O, Badjatia N, Boase K, Bodien Y, Corrigan JD, Crawford K, Dikmen S, Duhaime AC, Ellenbogen R, Feeser VR, Ferguson AR, Foreman B, Gardner R, Gaudette E, Gonzalez L, Gopinath S, Gullapalli R, Hemphill JC, Hotz G, Keene CD, Kramer J, Kreitzer N, Lindsell C, Machamer J, Madden C, Martin A, McAllister T, Merchant R, Nelson L, Ngwenya LB, Noel F, Nolan A, Palacios E, Perl D, Rabinowitz M, Rosand J, Sander A, Satris G, Schnyer D, Seabury S, Toga A, Valadka A, Vassar M, Zafonte R. Pathological Computed Tomography Features Associated With Adverse Outcomes After Mild Traumatic Brain Injury: A TRACK-TBI Study With External Validation in CENTER-TBI. JAMA Neurol 2021; 78:1137-1148. [PMID: 34279565 PMCID: PMC8290344 DOI: 10.1001/jamaneurol.2021.2120] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Question Are different patterns of intracranial injury on head computed tomography associated with prognosis after mild traumatic brain injury (mTBI)? Findings In this cohort study, subarachnoid hemorrhage, subdural hematoma, and contusion often co-occurred and were associated with both incomplete recovery and more severe impairment out to 12 months after injury, while intraventricular and/or petechial hemorrhage co-occurred and were associated with more severe impairment up to 12 months after injury; epidural hematoma was associated with incomplete recovery at some points but not with more severe impairment. Some intracranial hemorrhage patterns were more strongly associated with outcomes than previously validated demographic and clinical variables. Meaning In this study, different pathological features on head computed tomography carried different implications for mild traumatic brain injury prognosis to 1 year. Importance A head computed tomography (CT) with positive results for acute intracranial hemorrhage is the gold-standard diagnostic biomarker for acute traumatic brain injury (TBI). In moderate to severe TBI (Glasgow Coma Scale [GCS] scores 3-12), some CT features have been shown to be associated with outcomes. In mild TBI (mTBI; GCS scores 13-15), distribution and co-occurrence of pathological CT features and their prognostic importance are not well understood. Objective To identify pathological CT features associated with adverse outcomes after mTBI. Design, Setting, and Participants The longitudinal, observational Transforming Research and Clinical Knowledge in Traumatic Brain Injury (TRACK-TBI) study enrolled patients with TBI, including those 17 years and older with GCS scores of 13 to 15 who presented to emergency departments at 18 US level 1 trauma centers between February 26, 2014, and August 8, 2018, and underwent head CT imaging within 24 hours of TBI. Evaluations of CT imaging used TBI Common Data Elements. Glasgow Outcome Scale–Extended (GOSE) scores were assessed at 2 weeks and 3, 6, and 12 months postinjury. External validation of results was performed via the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) study. Data analyses were completed from February 2020 to February 2021. Exposures Acute nonpenetrating head trauma. Main Outcomes and Measures Frequency, co-occurrence, and clustering of CT features; incomplete recovery (GOSE scores <8 vs 8); and an unfavorable outcome (GOSE scores <5 vs ≥5) at 2 weeks and 3, 6, and 12 months. Results In 1935 patients with mTBI (mean [SD] age, 41.5 [17.6] years; 1286 men [66.5%]) in the TRACK-TBI cohort and 2594 patients with mTBI (mean [SD] age, 51.8 [20.3] years; 1658 men [63.9%]) in an external validation cohort, hierarchical cluster analysis identified 3 major clusters of CT features: contusion, subarachnoid hemorrhage, and/or subdural hematoma; intraventricular and/or petechial hemorrhage; and epidural hematoma. Contusion, subarachnoid hemorrhage, and/or subdural hematoma features were associated with incomplete recovery (odds ratios [ORs] for GOSE scores <8 at 1 year: TRACK-TBI, 1.80 [95% CI, 1.39-2.33]; CENTER-TBI, 2.73 [95% CI, 2.18-3.41]) and greater degrees of unfavorable outcomes (ORs for GOSE scores <5 at 1 year: TRACK-TBI, 3.23 [95% CI, 1.59-6.58]; CENTER-TBI, 1.68 [95% CI, 1.13-2.49]) out to 12 months after injury, but epidural hematoma was not. Intraventricular and/or petechial hemorrhage was associated with greater degrees of unfavorable outcomes up to 12 months after injury (eg, OR for GOSE scores <5 at 1 year in TRACK-TBI: 3.47 [95% CI, 1.66-7.26]). Some CT features were more strongly associated with outcomes than previously validated variables (eg, ORs for GOSE scores <5 at 1 year in TRACK-TBI: neuropsychiatric history, 1.43 [95% CI .98-2.10] vs contusion, subarachnoid hemorrhage, and/or subdural hematoma, 3.23 [95% CI 1.59-6.58]). Findings were externally validated in 2594 patients with mTBI enrolled in the CENTER-TBI study. Conclusions and Relevance In this study, pathological CT features carried different prognostic implications after mTBI to 1 year postinjury. Some patterns of injury were associated with worse outcomes than others. These results support that patients with mTBI and these CT features need TBI-specific education and systematic follow-up.
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Affiliation(s)
- Esther L Yuh
- Brain and Spinal Injury Center, San Francisco, California.,Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco
| | - Sonia Jain
- Biostatistics Research Center, Herbert Wertheim School of Public Health and Human Longevity Science, University of California, San Diego, La Jolla
| | - Xiaoying Sun
- Biostatistics Research Center, Herbert Wertheim School of Public Health and Human Longevity Science, University of California, San Diego, La Jolla
| | - Dana Pisica
- Department of Neurosurgery, Erasmus Medical Center, Rotterdam, the Netherlands.,Department of Public Health, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Mark H Harris
- Brain and Spinal Injury Center, San Francisco, California.,Department of Neurological Surgery, University of California, San Francisco, San Francisco
| | - Sabrina R Taylor
- Brain and Spinal Injury Center, San Francisco, California.,Department of Neurological Surgery, University of California, San Francisco, San Francisco
| | - Amy J Markowitz
- Brain and Spinal Injury Center, San Francisco, California.,Department of Neurological Surgery, University of California, San Francisco, San Francisco
| | - Pratik Mukherjee
- Brain and Spinal Injury Center, San Francisco, California.,Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco
| | - Jan Verheyden
- Research and Development, Icometrix, Leuven, Belgium
| | - Joseph T Giacino
- Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Charlestown, Massachusetts.,Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, Massachusetts
| | - Harvey S Levin
- Department of Physical Medicine and Rehabilitation, Baylor College of Medicine, Houston, Texas
| | - Michael McCrea
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee
| | - Murray B Stein
- Department of Psychiatry, University of California San Diego, La Jolla.,Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Nancy R Temkin
- Department of Neurological Surgery, University of Washington, Seattle
| | | | | | - Hester F Lingsma
- Department of Public Health, Erasmus Medical Center, Rotterdam, the Netherlands
| | - David O Okonkwo
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Andrew I R Maas
- Department of Neurosurgery, Antwerp University Hospital and University of Antwerp, Edegem, Belgium
| | - Geoffrey T Manley
- Brain and Spinal Injury Center, San Francisco, California.,Department of Neurological Surgery, University of California, San Francisco, San Francisco
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Joel Kramer
- University of California, San Francisco, San Francisco
| | | | | | | | | | | | | | | | | | | | | | - Amber Nolan
- University of California, San Francisco, San Francisco
| | - Eva Palacios
- University of California, San Francisco, San Francisco
| | - Daniel Perl
- Uniformed Services University, Bethesda, Maryland
| | | | | | | | | | | | | | - Arthur Toga
- University of Southern California, Los Angeles
| | | | - Mary Vassar
- University of California, San Francisco, San Francisco
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10
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Tsolinas RE, Burke JF, DiGiorgio AM, Thomas LH, Duong-Fernandez X, Harris MH, Yue JK, Winkler EA, Suen CG, Pascual LU, Ferguson AR, Huie JR, Pan JZ, Hemmerle DD, Singh V, Torres-Espin A, Omondi C, Kyritsis N, Haefeli J, Weinstein PR, de Almeida Neto CA, Kuo YH, Taggard D, Talbott JF, Whetstone WD, Manley GT, Bresnahan JC, Beattie MS, Dhall SS. Transforming Research and Clinical Knowledge in Spinal Cord Injury (TRACK-SCI): an overview of initial enrollment and demographics. Neurosurg Focus 2021; 48:E6. [PMID: 32357323 DOI: 10.3171/2020.2.focus191030] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 02/14/2020] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Traumatic spinal cord injury (SCI) is a dreaded condition that can lead to paralysis and severe disability. With few treatment options available for patients who have suffered from SCI, it is important to develop prospective databases to standardize data collection in order to develop new therapeutic approaches and guidelines. Here, the authors present an overview of their multicenter, prospective, observational patient registry, Transforming Research and Clinical Knowledge in SCI (TRACK-SCI). METHODS Data were collected using the National Institute of Neurological Disorders and Stroke (NINDS) common data elements (CDEs). Highly granular clinical information, in addition to standardized imaging, biospecimen, and follow-up data, were included in the registry. Surgical approaches were determined by the surgeon treating each patient; however, they were carefully documented and compared within and across study sites. Follow-up visits were scheduled for 6 and 12 months after injury. RESULTS One hundred sixty patients were enrolled in the TRACK-SCI study. In this overview, basic clinical, imaging, neurological severity, and follow-up data on these patients are presented. Overall, 78.8% of the patients were determined to be surgical candidates and underwent spinal decompression and/or stabilization. Follow-up rates to date at 6 and 12 months are 45% and 36.3%, respectively. Overall resources required for clinical research coordination are also discussed. CONCLUSIONS The authors established the feasibility of SCI CDE implementation in a multicenter, prospective observational study. Through the application of standardized SCI CDEs and expansion of future multicenter collaborations, they hope to advance SCI research and improve treatment.
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Affiliation(s)
- Rachel E Tsolinas
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of
| | - John F Burke
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery
| | - Anthony M DiGiorgio
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery
| | - Leigh H Thomas
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery.,3Weill Institutes for Neuroscience
| | - Xuan Duong-Fernandez
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery.,3Weill Institutes for Neuroscience
| | - Mark H Harris
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery.,3Weill Institutes for Neuroscience
| | - John K Yue
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery
| | - Ethan A Winkler
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery
| | - Catherine G Suen
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery
| | - Lisa U Pascual
- 4Orthopaedic Surgery and Orthopedic Trauma Institute, Zuckerberg San Francisco General Hospital.,5Orthopedic Surgery
| | - Adam R Ferguson
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery.,3Weill Institutes for Neuroscience.,6San Francisco Veterans Affairs Healthcare System
| | - J Russell Huie
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery.,3Weill Institutes for Neuroscience
| | - Jonathan Z Pan
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,7Anesthesia and Perioperative Care
| | - Debra D Hemmerle
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery.,3Weill Institutes for Neuroscience
| | - Vineeta Singh
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,3Weill Institutes for Neuroscience.,8Neurology, and
| | - Abel Torres-Espin
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery
| | - Cleopa Omondi
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery.,3Weill Institutes for Neuroscience
| | - Nikos Kyritsis
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery.,3Weill Institutes for Neuroscience
| | - Jenny Haefeli
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery
| | - Philip R Weinstein
- 2Neurological Surgery.,3Weill Institutes for Neuroscience.,9Institute for Neurodegenerative Diseases, Spine Center, University of California San Francisco
| | - Carlos A de Almeida Neto
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery.,3Weill Institutes for Neuroscience
| | - Yu-Hung Kuo
- 12Department of Neurological Surgery, University of California San Francisco-Fresno, Fresno, California
| | - Derek Taggard
- 12Department of Neurological Surgery, University of California San Francisco-Fresno, Fresno, California
| | - Jason F Talbott
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,10Department of Radiology and Biomedical Imaging, Zuckerberg San Francisco General Hospital, San Francisco; and
| | | | - Geoffrey T Manley
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery
| | - Jacqueline C Bresnahan
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery.,3Weill Institutes for Neuroscience
| | - Michael S Beattie
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery.,3Weill Institutes for Neuroscience
| | - Sanjay S Dhall
- 1Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital; Departments of.,2Neurological Surgery
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11
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Cooper FW, Harris MH, Kahn JW. Ligation and Division of the Abdominal Aorta for Metallic Embolus from the Heart: Postoperative Observations of the Circulation in the Extremities. Ann Surg 2007; 127:1-11. [PMID: 17859050 PMCID: PMC1513755 DOI: 10.1097/00000658-194801000-00001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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12
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Gottlieb E, Armour SM, Harris MH, Thompson CB. Mitochondrial membrane potential regulates matrix configuration and cytochrome c release during apoptosis. Cell Death Differ 2003; 10:709-17. [PMID: 12761579 DOI: 10.1038/sj.cdd.4401231] [Citation(s) in RCA: 545] [Impact Index Per Article: 26.0] [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] Open
Abstract
During apoptosis, the mitochondrial membrane potential (MMP) decreases, but it is not known how this relates to the apoptotic process. It was recently suggested that cytochrome c is compartmentalized in closed cristal regions and therefore, matrix remodeling is required to attain complete cytochrome c release from the mitochondria. In this work we show that, at the onset of apoptosis, changes in MMP control matrix remodeling prior to cytochrome c release. Early after growth factor withdrawal the MMP declines and the matrix condenses. Both phenomena are reversed by adding oxidizable substrates. In mitochondria isolated from healthy cells, matrix condensation can be induced by either denying oxidizable substrates or by protonophores that dissipate the membrane potential. Matrix remodeling to the condensed state results in cristal unfolding and exposes cytochrome c to the intermembrane space facilitating its release from the mitochondria during apoptosis. In contrast, when a transmembrane potential is generated due to either electron transport or a pH gradient formed by acidifying the medium, mitochondria maintain an orthodox configuration in which most cytochrome c is sequestered in the cristae and is resistant to release by agents that disrupt the mitochondrial outer membrane.
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Affiliation(s)
- E Gottlieb
- Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia 19104, USA
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13
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Vander Heiden MG, Plas DR, Rathmell JC, Fox CJ, Harris MH, Thompson CB. Growth factors can influence cell growth and survival through effects on glucose metabolism. Mol Cell Biol 2001; 21:5899-912. [PMID: 11486029 PMCID: PMC87309 DOI: 10.1128/mcb.21.17.5899-5912.2001] [Citation(s) in RCA: 407] [Impact Index Per Article: 17.7] [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
Cells from multicellular organisms are dependent upon exogenous signals for survival, growth, and proliferation. The relationship among these three processes was examined using an interleukin-3 (IL-3)-dependent cell line. No fixed dose of IL-3 determined the threshold below which cells underwent apoptosis. Instead, increasing growth factor concentrations resulted in progressive shortening of the G(1) phase of the cell cycle and more rapid proliferative expansion. Increased growth factor concentrations also resulted in proportional increases in glycolytic rates. Paradoxically, cells growing in high concentrations of growth factor had an increased susceptibility to cell death upon growth factor withdrawal. This susceptibility correlated with the magnitude of the change in the glycolytic rate following growth factor withdrawal. To investigate whether changes in the availability of glycolytic products influence mitochondrion-initiated apoptosis, we artificially limited glycolysis by manipulating the glucose levels in the medium. Like growth factor withdrawal, glucose limitation resulted in Bax translocation, a decrease in mitochondrial membrane potential, and cytochrome c redistribution to the cytosol. In contrast, increasing cell autonomous glucose uptake by overexpression of Glut1 significantly delayed apoptosis following growth factor withdrawal. These data suggest that a primary function of growth factors is to regulate glucose uptake and metabolism and thus maintain mitochondrial homeostasis and enable anabolic pathways required for cell growth. Consistent with this hypothesis, expression of the three genes involved in glucose uptake and glycolytic commitment, those for Glut1, hexokinase 2, and phosphofructokinase 1, was found to rapidly decline to nearly undetectable levels following growth factor withdrawal.
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Affiliation(s)
- M G Vander Heiden
- Abramson Family Cancer Research Institute, University of Pennsylvania, 450 BRB II, 421 Curie Blvd., Philadelphia, PA 19104, USA
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14
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Thompson CB, Rathmell JC, Frauwirth KA, Lindsten T, Rudin CM, Opferman JT, Ashton-Rickardt PG, Harris MH, Chandel NS, Schumacker PT, Vander Heiden MG. What keeps a resting T cell alive? Cold Spring Harb Symp Quant Biol 2001; 64:383-7. [PMID: 11232311 DOI: 10.1101/sqb.1999.64.383] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- C B Thompson
- Gwen Knapp Center, University of Chicago, Chicago, Illinois 60637, USA
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15
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Abstract
Mitochondria are well known as sites of electron transport and generators of cellular ATP. Mitochondria also appear to be sites of cell survival regulation. In the process of programmed cell death, mediators of apoptosis can be released from mitochondria through disruptions in the outer mitochondrial membrane; these mediators then participate in the activation of caspases and of DNA degradation. Thus the regulation of outer mitochondrial membrane integrity is an important control point for apoptosis. The Bcl-2 family is made up of outer mitochondrial membrane proteins that can regulate cell survival, but the mechanisms by which Bcl-2 family proteins act remain controversial. Most metabolites are permeant to the outer membrane through the voltage dependent anion channel (VDAC), and Bcl-2 family proteins appear to be able to regulate VDAC function. In addition, many Bcl-2 family proteins can form channels in vitro, and some pro-apoptotic members may form multimeric channels large enough to release apoptosis promoting proteins from the intermembrane space. Alternatively, Bcl-2 family proteins have been hypothesized to coordinate the permeability of both the outer and inner mitochondrial membranes through the permeability transition (PT) pore. Increasing evidence suggests that alterations in cellular metabolism can lead to pro-apoptotic changes, including changes in intracellular pH, redox potential and ion transport. By regulating mitochondrial membrane physiology, Bcl-2 proteins also affect mitochondrial energy generation, and thus influence cellular bioenergetics. Cell Death and Differentiation (2000) 7, 1182 - 1191
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Affiliation(s)
- M H Harris
- Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
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16
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Rathmell JC, Vander Heiden MG, Harris MH, Frauwirth KA, Thompson CB. In the absence of extrinsic signals, nutrient utilization by lymphocytes is insufficient to maintain either cell size or viability. Mol Cell 2000; 6:683-92. [PMID: 11030347 DOI: 10.1016/s1097-2765(00)00066-6] [Citation(s) in RCA: 351] [Impact Index Per Article: 14.6] [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: 10/26/2022]
Abstract
Without receptor stimulation, cells from multicellular organisms die by apoptosis. Here we show that lymphocytes deprived of receptor stimulation undergo progressive atrophy before commitment to apoptosis. Following loss of receptor engagement, lymphocytes rapidly downregulated the glucose transporter, glut1. This was accompanied by reduction in mitochondrial potential and cellular ATP, suggesting that atrophy resulted from depletion of glucose-derived metabolic substrates. Expression of the antiapoptotic protein, Bcl-X(L), prevented death but not atrophy following either growth factor or glucose withdrawal. In Bcl-X(L) transgenic animals, size and metabolic activity of naive T cells were regulated through the TCR and correlated with TCR-dependent glut1 expression. These data suggest that ligands for cell-specific receptors promote cell survival by regulating nutrient uptake and utilization.
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Affiliation(s)
- J C Rathmell
- Department of Cancer Biology and Medicine and Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia 19104, USA
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17
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Abstract
The Bcl-2-related protein Bax is toxic when expressed either in yeast or in mammalian cells. Although the mechanism of this toxicity is unknown, it appears to be similar in both cell types and dependent on the localization of Bax to the outer mitochondrial membrane. To investigate the role of mitochondrial respiration in Bax-mediated toxicity, a series of yeast mutant strains was created, each carrying a disruption in either a component of the mitochondrial electron transport chain, a component of the mitochondrial ATP synthesis machinery, or a protein involved in mitochondrial adenine nucleotide exchange. Bax toxicity was reduced in strains lacking the ability to perform oxidative phosphorylation. In contrast, a respiratory-competent strain that lacked the outer mitochondrial membrane Por1 protein showed increased sensitivity to Bax expression. Deficiencies in other mitochondrial proteins did not affect Bax toxicity as long as the ability to perform oxidative phosphorylation was maintained. Characterization of Bax-induced toxicity in wild-type yeast demonstrated a growth inhibition that preceded cell death. This growth inhibition was associated with a decreased ability to carry out oxidative phosphorylation following Bax induction. Furthermore, cells recovered following Bax-induced growth arrest were enriched for a petite phenotype and were no longer able to grow on a nonfermentable carbon source. These results suggest that Bax expression leads to an impairment of mitochondrial respiration, inducing toxicity in cells dependent on oxidative phosphorylation for survival. Furthermore, Bax toxicity is enhanced in yeast deficient in the ability to exchange metabolites across the outer mitochondrial membrane.
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Affiliation(s)
- M H Harris
- Abramson Family Cancer Research Institute and Department of Cancer Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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18
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Chang BS, Kelekar A, Harris MH, Harlan JE, Fesik SW, Thompson CB. The BH3 domain of Bcl-x(S) is required for inhibition of the antiapoptotic function of Bcl-x(L). Mol Cell Biol 1999; 19:6673-81. [PMID: 10490606 PMCID: PMC84651 DOI: 10.1128/mcb.19.10.6673] [Citation(s) in RCA: 34] [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: 11/20/2022] Open
Abstract
bcl-x is a member of the bcl-2 family of genes. The major protein product, Bcl-x(L), is a 233-amino-acid protein which has antiapoptotic properties. In contrast, one of the alternatively spliced transcripts of the bcl-x gene codes for the protein Bcl-x(S), which lacks 63 amino acids present in Bcl-x(L) and has proapoptotic activity. Unlike other proapoptotic Bcl-2 family members, such as Bax and Bak, Bcl-x(S) does not seem to induce cell death in the absence of an additional death signal. However, Bcl-x(S) does interfere with the ability of Bcl-x(L) to antagonize Bax-induced death in transiently transfected 293 cells. Mutational analysis of Bcl-x(S) was conducted to identify the domains necessary to mediate its proapoptotic phenotype. Deletion mutants of Bcl-x(S) which still contained an intact BH3 domain retained the ability to inhibit survival through antagonism of Bcl-x(L). Bcl-x(S) was able to form heterodimers with Bcl-x(L) in mammalian cells, and its ability to inhibit survival correlated with the ability to heterodimerize with Bcl-x(L). Deletion mutants of Bax and Bcl-2, which lacked BH1 and BH2 domains but contained a BH3 domain, were able to antagonize the survival effect conferred by Bcl-x(L). The results suggest that BH3 domains from both pro- and antiapoptotic Bcl-2 family members, while lacking an intrinsic ability to promote programmed cell death, can be potent inhibitors of Bcl-x(L) survival function.
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Affiliation(s)
- B S Chang
- Gwen Knapp Center for Lupus and Immunology Research, The University of Chicago, Chicago, Illinois 60637, USA
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19
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Abstract
We report the identification of 11 impurities in variously stressed chlorhexidine digluconate (CHG) solutions. The structural assignment of each CHG impurity involved tentative identification from HPLC-MS data followed by synthesis of the appropriate standard, isolation of the impurity from the CHG solution by flash chromatography, and comparison of HPLC-MS, HPLC-UV, and NMR data of the impurity with the standard. Six of the synthetic impurity standards represent new compounds. Degradation studies of CHG solutions systematically stressed by heat, light, and low pH are reported with identification and approximate quantification of resulting impurities. Degradation mechanisms were proposed for each set of stress conditions applied to CHG solutions. Parallels were noted between the way CHG degrades in the thermospray interface of the HPLC-MS and the way CHG degrades with shelf time. Similarities were noted in the synthetic starting materials of CHG and the final degradation products.
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Affiliation(s)
- L K Revelle
- Food and Drug Administration, Division of Drug Analysis, St. Louis, Missouri 63101
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21
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Perrett DI, Harris MH, Mistlin AJ, Hietanen JK, Benson PJ, Bevan R, Thomas S, Oram MW, Ortega J, Brierly K. Social Signals Analyzed at the Single Cell Level: Someone is Looking at Me, Something Moved! International Journal of Comparative Psychology 1990. [DOI: 10.46867/c4x88p] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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22
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Abstract
The apicoectomy with retrograde amalgam is an excellent and accepted surgical technique for salvaging teeth. Anatomic considerations in molar teeth are not a contraindication to this technique.
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23
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Buonocore V, Harris MH, Schlesinger S. Properties of tyrosyl transfer ribonucleic acid synthetase from two tyrS mutants of Escherichia coli K-12. J Biol Chem 1972; 247:4843-9. [PMID: 4626368] [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: 01/11/2023] Open
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24
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Narang R, Ruben MP, Harris MH, Wells H. Improved healing of experimental defects in the canine mandible by grafts of decalcified allogenic bone. Oral Surg Oral Med Oral Pathol 1970; 30:142-50. [PMID: 4913727 DOI: 10.1016/0030-4220(70)90023-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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26
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Elkin DC, Harris MH. Arteriovenous Aneurysm of the Vertebral Vessels : Report of Ten Cases. Ann Surg 1946; 124:934-49. [PMID: 17858886 PMCID: PMC1803271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
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27
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