1
|
Kolbeinsson HM, Aubrey J, Lypka MM, Pounders S, Krech LA, Fisk CS, Chapman AJ, Gibson CJ. Out of sight, out of mind? The impact on trauma patient opioid use when the medicine administration schedule is not displayed. Am J Surg 2023; 225:504-507. [PMID: 36631372 DOI: 10.1016/j.amjsurg.2023.01.007] [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: 08/25/2022] [Revised: 11/30/2022] [Accepted: 01/06/2023] [Indexed: 01/09/2023]
Abstract
INTRODUCTION The impact of a visual pain medication schedule on opioid use among hospitalized trauma patients is unknown. We examined whether removal of this displayed schedule would decrease oral morphine equivalent (OME) use. METHODS This retrospective cohort study compared OME use in trauma patients in the inpatient setting before and after removing the patient-facing pain medication schedule that is typically displayed on the patient's white board for all trauma admissions. RESULTS 707 patients were included. The control (n = 308, 43.6%) and intervention (n = 399, 56.4%) groups were similar in age (p = 0.06). There was no difference in total inpatient OME use between the control and intervention groups, median 50 (IQR: 22.5-118) vs 60 (IQR: 22.5-126), p = 0.79, respectively. No difference in total OME use was observed when patients were stratified by age, sex, race, ISS, and length of hospital stay. CONCLUSION Removing a visual display of the pain medication schedule did not decrease OME use in inpatient trauma patients.
Collapse
Affiliation(s)
- Hordur M Kolbeinsson
- Spectrum Health/Michigan State University, General Surgery Residency, Grand Rapids, MI, USA.
| | - Jason Aubrey
- Spectrum Health/Michigan State University, General Surgery Residency, Grand Rapids, MI, USA
| | | | - Steffen Pounders
- Spectrum Health Trauma Research Institute, Grand Rapids, MI, USA
| | - Laura A Krech
- Spectrum Health Trauma Research Institute, Grand Rapids, MI, USA
| | - Chelsea S Fisk
- Spectrum Health Trauma Research Institute, Grand Rapids, MI, USA
| | - Alistair J Chapman
- Spectrum Health/Michigan State University, General Surgery Residency, Grand Rapids, MI, USA; Spectrum Health Trauma Research Institute, Grand Rapids, MI, USA; Spectrum Health Medical Group, Division of Acute Care Surgery, Grand Rapids, MI, USA
| | - Charles J Gibson
- Spectrum Health/Michigan State University, General Surgery Residency, Grand Rapids, MI, USA; Spectrum Health Trauma Research Institute, Grand Rapids, MI, USA; Spectrum Health Medical Group, Division of Acute Care Surgery, Grand Rapids, MI, USA
| |
Collapse
|
2
|
Kelly-Schuette KA, Chapman AJ, Messer LE, Kuk CC, Lypka MM, Krech LA, Pounders SJ, Iskander GA, Gibson CJ. Hotter Than It Looks: A Retrospective Review of Patients With Cholecystitis and With Negative Imaging. J Surg Res 2022; 273:93-99. [PMID: 35033822 DOI: 10.1016/j.jss.2021.12.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 10/27/2021] [Accepted: 12/04/2021] [Indexed: 12/07/2022]
Abstract
INTRODUCTION Ultrasound is the gold standard for workup of cholecystitis in the emergency department, and findings heavily influence clinical decision-making. Patients with negative imaging for acute cholecystitis may be inappropriately sent home. The purpose of our study was to review the pathology and outcomes of patients presenting with biliary pain and negative ultrasound findings of acute cholecystitis. MATERIALS AND METHODS Emergency department patients who underwent laparoscopic cholecystectomy between January 2015 and February 2019 were reviewed retrospectively. Only patients with negative or equivocal imaging were included. The primary outcome was the incidence of cholecystitis on final pathology. RESULTS Two hundred fifty-seven patients underwent laparoscopic cholecystectomy. Pathology demonstrated cholecystitis in 84% of patients. Only 15% of patients had cholelithiasis without cholecystitis on pathology. The incidence of cholecystitis was similar in negative and equivocal imaging groups (84% versus 83%; P = 0.960). The median time from admission to the operating room was 12.1 h (interquartile range 7.1-18.3 h), and hospital length of stay was 1.2 d (interquartile range 0.8-1.7 d). CONCLUSIONS This study found that patients with negative or equivocal imaging had cholecystitis on pathology. On review of patient outcomes, those patients who underwent surgical intervention had a low rate of complications and short hospital stay.
Collapse
Affiliation(s)
- Kathrine A Kelly-Schuette
- Spectrum Health, Michigan State University College of Human Medicine, General Surgery Residency, Grand Rapids, Michigan.
| | - Alistair J Chapman
- Spectrum Health Acute Care Surgery, Grand Rapids, Michigan; Spectrum Health Office of Research, Grand Rapids, Michigan
| | - Lauren E Messer
- Spectrum Health Trauma Research Institute, Grand Rapids, Michigan
| | - ChiuYing C Kuk
- Spectrum Health Trauma Research Institute, Grand Rapids, Michigan
| | - Matthew M Lypka
- Michigan State University College of Human Medicine, Grand Rapids, Michigan
| | - Laura A Krech
- Spectrum Health Acute Care Surgery, Grand Rapids, Michigan; Spectrum Health Office of Research, Grand Rapids, Michigan
| | - Steffen J Pounders
- Spectrum Health Office of Research, Grand Rapids, Michigan; Michigan State University College of Human Medicine, Grand Rapids, Michigan
| | - Gaby A Iskander
- Spectrum Health Acute Care Surgery, Grand Rapids, Michigan; Spectrum Health Office of Research, Grand Rapids, Michigan
| | - Charles J Gibson
- Spectrum Health Acute Care Surgery, Grand Rapids, Michigan; Spectrum Health Office of Research, Grand Rapids, Michigan; Spectrum Health Trauma Research Institute, Grand Rapids, Michigan
| |
Collapse
|
3
|
Saunders RN, Kelly-Schuette KA, Davis AT, Koehler TJ, Gayed BN, Durling LT, Chapman AJ, Gibson CJ. Sumping's Up: A Multidisciplinary Educational Initiative on Gastric Drainage Tubes. J Contin Educ Nurs 2021; 51:484-488. [PMID: 32976618 DOI: 10.3928/00220124-20200914-11] [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] [Received: 12/09/2019] [Accepted: 05/04/2020] [Indexed: 11/20/2022]
Abstract
BACKGROUND Nasogastric tube placement is widely taught, and tube maintenance relies on astute nursing care with adherence to both institutional and evidence-based recommendations. However, precise adherence to current recommendations relies on knowledge base regarding the identification of malfunctioning gastric drainage tubes. Troubleshooting skills are crucial in maintaining patient safety and recognizing malfunction. METHOD Educational sessions on nasogastric and orogastric decompression tube management, led by a surgical intensive care fellow at a level 1 trauma center, were offered to critical care nurses. A presession and postsession survey evaluated the nurses' subjective and objective knowledge and comfort with naso/orogastric decompression tube management. RESULTS Ninety-seven critical care RNs participated. For all questions, the proportion of correct answers significantly increased from presession survey to postsession survey (p < .001). Ninety-seven percent of all participants found the session to be very helpful. CONCLUSION Physician-led educational sessions on naso/orogastric decompression tube management were well-received and improved subjective and objective measurements of nurses' knowledge and comfort level with gastric decompression tubes. [J Contin Educ Nurs. 2020;51(10):484-488.].
Collapse
|
4
|
Kelly-Schuette KA, Prentice A, Orr A, Levine A, Zarnke A, Pardington E, Pounders S, Lypka M, Krech L, Iskander G, Chapman AJ, Gibson CJ, Steensma E, Durling L. Rib Fracture Mortality: Are there clues in the core? J Surg Res 2021; 268:25-32. [PMID: 34280662 DOI: 10.1016/j.jss.2021.06.020] [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: 03/17/2021] [Revised: 05/11/2021] [Accepted: 06/10/2021] [Indexed: 11/26/2022]
Abstract
BACKGROUND Sarcopenia is associated with increased morbidity and mortality in the trauma patient. The primary objective of this study was to determine the relationship of psoas cross sectional area with hospital mortality in patients with rib fractures over the age of 55 years. MATERIALS AND METHODS We retrospectively reviewed 1223 patients presenting to a Level 1 Trauma Center between 1/1/2002 and 1/31/2019. Psoas cross sectional area was measured using a polygonal tracing tool. Patients were stratified into four quartiles based on sex-specific values. RESULTS There was increased in-hospital mortality for patients with a lower psoas cross sectional area (10 %, 8%, 6%, and 4%, Q1-Q4 respectively; P=0.021). The logistic regression model determined for every increase in psoas cross sectional area by 1 cm2 the odds of in-hospital mortality decreased by 4%. CONCLUSIONS In-hospital mortality is multifactorial; however, psoas cross sectional area may provide a clue in predicting adverse outcomes after traumatic rib fractures.
Collapse
Affiliation(s)
- Kathrine A Kelly-Schuette
- Spectrum Health/Michigan State University College of Human Medicine General Surgery Residency, Grand Rapids, MI.
| | - Anthony Prentice
- Spectrum Health Department of Nursing, Surgical Services, Grand Rapids, MI
| | - Adam Orr
- Spectrum Health/Michigan State University College of Human Medicine Diagnostic Radiology Residency, Grand Rapids, MI
| | - Anna Levine
- Spectrum Health/Michigan State University College of Human Medicine General Surgery Residency, Grand Rapids, MI
| | - Allison Zarnke
- Spectrum Health/Michigan State University College of Human Medicine General Surgery Residency, Grand Rapids, MI
| | - Emily Pardington
- Spectrum Health/Michigan State University College of Human Medicine General Surgery Residency, Grand Rapids, MI
| | - Steffen Pounders
- Spectrum Health Office of Research, Grand Rapids, MI; Spectrum Health Trauma Research Institute, Grand Rapids, MI
| | - Matthew Lypka
- Spectrum Health Office of Research, Grand Rapids, MI; Spectrum Health Trauma Research Institute, Grand Rapids, MI
| | - Laura Krech
- Spectrum Health Trauma Research Institute, Grand Rapids, MI
| | - Gaby Iskander
- Spectrum Health/Michigan State University College of Human Medicine General Surgery Residency, Grand Rapids, MI; Spectrum Health Acute Care Surgery, Grand Rapids, MI; Spectrum Health Office of Research, Grand Rapids, MI; Spectrum Health Trauma Research Institute, Grand Rapids, MI
| | - Alistair J Chapman
- Spectrum Health/Michigan State University College of Human Medicine General Surgery Residency, Grand Rapids, MI; Spectrum Health Acute Care Surgery, Grand Rapids, MI; Spectrum Health Trauma Research Institute, Grand Rapids, MI
| | - Charles J Gibson
- Spectrum Health/Michigan State University College of Human Medicine General Surgery Residency, Grand Rapids, MI; Spectrum Health Acute Care Surgery, Grand Rapids, MI; Spectrum Health Trauma Research Institute, Grand Rapids, MI
| | - Elizabeth Steensma
- Spectrum Health/Michigan State University College of Human Medicine General Surgery Residency, Grand Rapids, MI; Spectrum Health Acute Care Surgery, Grand Rapids, MI; Spectrum Health Trauma Research Institute, Grand Rapids, MI
| | - Luke Durling
- Spectrum Health/Michigan State University College of Human Medicine General Surgery Residency, Grand Rapids, MI; Spectrum Health Acute Care Surgery, Grand Rapids, MI; Spectrum Health Trauma Research Institute, Grand Rapids, MI
| |
Collapse
|
5
|
Thorp SD, Le J, Adams NS, Davis AT, Gibson CJ, Wright GP, Rodriguez CH, Krech L, Iskander GA, Chapman AJ. Are motorcycles really "donorcycles"? Examining organ donation rates between unhelmeted and helmeted motorcyclists. J Safety Res 2020; 75:173-177. [PMID: 33334475 DOI: 10.1016/j.jsr.2020.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 03/15/2020] [Accepted: 09/16/2020] [Indexed: 06/12/2023]
Abstract
INTRODUCTION Motorcycles are colloquially referred to as "donorcycles" among medical staff. However, the actual impact of helmet laws and helmet use on organ donation is unknown. Michigan's 35-year-old universal helmet law (UHL) was repealed in April 2012 and replaced by a partial-helmet law. We hypothesized that there would be an increase in organ donation rates from unhelmeted motorcyclist fatalities. METHODS Michigan's Gift of Life Michigan organ donation database was queried from April 2008 through May 2015 in conjunction with the Michigan Trauma Quality Improvement Program database from the same time period. All in-hospital motorcycle crash fatalities were examined. RESULTS A three-fold increase was found in the rate of organ donation for unhelmeted motorcyclists compared to helmeted motorcyclists (p = 0.006). Motorcycle crash fatalities tended to be younger in age after the UHL repeal with an average age of 32.8 years versus 40.8, however, this finding was not statistically significant (p = 0.071). Additionally, there was no significant difference in organ donation rates pre-UHL repeal (2008-2012) versus post-repeal (2012-2015). CONCLUSIONS This is the first study to demonstrate an increased rate of organ donation among unhelmeted motorcyclist fatalities compared to helmeted rider fatalities. There was no significant increase in the rate of organ donation following the Michigan UHL repeal. However, we identified that some motorcycle crash fatalities were from illegally unhelmeted riders in the past, prior to the repeal. Practical Application: Unhelmeted motorcyclists are three times more likely than helmeted riders to become organ donors, possibly due to the well documented increase in severe traumatic brain injuries in this population. From a public health perspective, helmets should be required for all motorcyclists and efforts to advocate in favor of helmet legislation should be supported by trauma systems and health professionals.
Collapse
Affiliation(s)
- Stephen D Thorp
- Spectrum Health/Michigan State University General Surgery Residency, Grand Rapids, MI, United States.
| | - Julie Le
- Spectrum Health/Michigan State University General Surgery Residency, Grand Rapids, MI, United States
| | - Nicholas S Adams
- Spectrum Health/Michigan State University Plastic Surgery Residency, Grand Rapids, MI, United States
| | - Alan T Davis
- Department of Surgery, Michigan State University, Grand Rapids, MI, United States
| | - Charles J Gibson
- Trauma Research Institute, Division of Acute Care Surgery, Spectrum Health Hospital, Michigan State University College of Human Medicine, Grand Rapids, MI, United States
| | - Gerald P Wright
- Division of Surgical Oncology, Spectrum Health Hospital, Michigan State University College of Human Medicine, Grand Rapids, MI, United States
| | - Carlos H Rodriguez
- Division of Acute Care Surgery, Spectrum Health Hospital, Michigan State University College of Human Medicine, Grand Rapids, MI, United States
| | - Laura Krech
- Trauma Research Institute, Division of Acute Care Surgery, Spectrum Health Hospital, Grand Rapids, MI, United States
| | - Gaby A Iskander
- Trauma Research Institute, Division of Acute Care Surgery, Spectrum Health Hospital, Michigan State University College of Human Medicine, Grand Rapids, MI, United States
| | - Alistair J Chapman
- Trauma Research Institute, Division of Acute Care Surgery, Spectrum Health Hospital, Michigan State University College of Human Medicine, Grand Rapids, MI, United States
| |
Collapse
|
6
|
Saunders RN, Witte AB, Adams NS, Dull MB, Davis AT, Gibson CJ, Iskander GA, Rodriguez CH, Cohle SD, Chapman AJ. Does the Repeal of Mandatory Motorcycle Safety Legislation Affect the Deaths of Motorcyclists? An Autopsy-Based Study Evaluating the Impact of Michigan's Universal Helmet Law Repeal on Immediately Fatal Motorcycle Crashes. Am Surg 2020; 86:e205-e207. [PMID: 32391781] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
|
7
|
Saunders RN, Witte AB, Adams NS, Dull MB, Davis AT, Gibson CJ, Iskander GA, Rodriguez CH, Cohle SD, Chapman AJ. Does the Repeal of Mandatory Motorcycle Safety Legislation Affect the Deaths of Motorcyclists? An Autopsy-Based Study Evaluating the Impact of Michigan's Universal Helmet Law Repeal on Immediately Fatal Motorcycle Crashes. Am Surg 2020. [DOI: 10.1177/000313482008600415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
| | - Amanda B. Witte
- College of Human Medicine Michigan State University Grand Rapids, Michigan
| | | | - Matthew B. Dull
- Spectrum Health Michigan State University Grand Rapids, Michigan
| | - Alan T. Davis
- Department of Surgery Spectrum Health College of Human Medicine Michigan State University Grand Rapids, Michigan
| | - Charles J. Gibson
- Acute Care Surgery Spectrum Health Hospital College of Human Medicine Michigan State University Grand Rapids, Michigan
| | - Gaby A. Iskander
- Acute Care Surgery Spectrum Health Hospital College of Human Medicine Michigan State University Grand Rapids, Michigan
| | - Carlos H. Rodriguez
- Department of Surgery Spectrum Health Hospital College of Human Medicine Michigan State University Grand Rapids, Michigan
| | - Stephen D. Cohle
- Office of the Medical Examiner- Kent County Grand Rapids, Michigan
| | - Alistair J. Chapman
- Acute Care Surgery Spectrum Health Hospital College of Human Medicine Michigan State University Grand Rapids, Michigan
| |
Collapse
|
8
|
Saunders RN, Dull MB, Witte AB, Regan JM, Davis AT, Koehler TJ, Gibson CJ, Iskander GA, Rodriguez CH, Cohle SD, Chapman AJ. The danger zone: Injuries and conditions associated with immediately fatal motorcycle crashes in the state of Michigan. Am J Surg 2018; 217:552-555. [PMID: 30352664 DOI: 10.1016/j.amjsurg.2018.10.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 10/03/2018] [Accepted: 10/03/2018] [Indexed: 11/19/2022]
Abstract
BACKGROUND Immediately fatal motorcycle crashes have not been well characterized. This study catalogues injuries sustained in fatal motorcycle crashes and assesses the impact of crash conditions on injury patterns. METHODS Autopsy records from the office of the medical examiner of Kent County, MI and publicly available traffic reports were queried for information pertaining to motorcyclists declared dead on-scene between January 1, 2007, and December 31, 2016. RESULTS A total of 71 autopsies of on-scene motorcycle crash fatalities were identified. The two most prevalent injuries were traumatic brain injury (TBI) (85%) and rib fractures (79%). The majority of fatalities occurred in daylight hours (54.3%) and in a 55 mph speed limit zone (63.8%). CONCLUSIONS This study provides a catalogue of the injuries sustained in immediately fatal motorcycle crashes and the associated conditions. Advocacy efforts that highlight the risks associated with motorcycle riding and that promote safe riding practices are warranted.
Collapse
Affiliation(s)
- Rachel N Saunders
- Spectrum Health/Michigan State University General Surgery Residency, 221 Michigan NE, Suite 402, Grand Rapids, MI, 49503, USA.
| | - Matthew B Dull
- Spectrum Health/Michigan State University Surgical Critical Care Fellowship, USA
| | - Amanda B Witte
- Michigan State University College of Human Medicine, USA
| | - James M Regan
- Spectrum Health/Michigan State University Surgical Critical Care Fellowship, USA
| | - Alan T Davis
- Spectrum Health, OME Scholarly Activity Support, Michigan State University Department of Surgery, USA
| | | | - Charles J Gibson
- Spectrum Health Hospital, Acute Care Surgery, Michigan State University College of Human Medicine, USA
| | - Gaby A Iskander
- Spectrum Health Hospital, Acute Care Surgery, Michigan State University College of Human Medicine, USA
| | - Carlos H Rodriguez
- Spectrum Health Hospital, Department of Surgery, Michigan State University College of Human Medicine, USA
| | | | - Alistair J Chapman
- Spectrum Health Hospital, Acute Care Surgery, Michigan State University College of Human Medicine, 221 Michigan NE, Suite 402, Grand Rapids, MI, 49503, USA.
| |
Collapse
|
9
|
Saunders RN, Hayakawa E, Gibson CJ, Chapman AJ. Clostridium septicum Myonecrosis Secondary to an Occult Small Bowel Adenocarcinoma. J Gastrointest Cancer 2018; 50:1001-1004. [PMID: 30198050 DOI: 10.1007/s12029-018-0168-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rachel N Saunders
- Spectrum Health/Michigan State University General Surgery Residency, 221 Michigan NE, Suite 402, Grand Rapids, MI, 49503, USA.
| | - Emiko Hayakawa
- Spectrum Health/Michigan State University General Surgery Residency, 221 Michigan NE, Suite 402, Grand Rapids, MI, 49503, USA
| | - Charles J Gibson
- Spectrum Health Hospital, Acute Care Surgery, 221 Michigan NE, Suite 402, Grand Rapids, MI, 49503, USA
| | - Alistair J Chapman
- Spectrum Health Hospital, Acute Care Surgery, 221 Michigan NE, Suite 402, Grand Rapids, MI, 49503, USA
| |
Collapse
|
10
|
Usmani SZ, Cavenagh JD, Belch AR, Hulin C, Basu S, White D, Nooka A, Ervin-Haynes A, Yiu W, Nagarwala Y, Berger A, Pelligra CG, Guo S, Binder G, Gibson CJ, Facon T. Cost-effectiveness of lenalidomide plus dexamethasone vs. bortezomib plus melphalan and prednisone in transplant-ineligible U.S. patients with newly-diagnosed multiple myeloma. J Med Econ 2016; 19:243-58. [PMID: 26517601 DOI: 10.3111/13696998.2015.1115407] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [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] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To conduct a cost-effectiveness assessment of lenalidomide plus dexamethasone (Rd) vs bortezomib plus melphalan and prednisone (VMP) as initial treatment for transplant-ineligible patients with newly-diagnosed multiple myeloma (MM), from a U.S. payer perspective. METHODS A partitioned survival model was developed to estimate expected life-years (LYs), quality-adjusted LYs (QALYs), direct costs and incremental costs per QALY and LY gained associated with use of Rd vs VMP over a patient's lifetime. Information on the efficacy and safety of Rd and VMP was based on data from multinational phase III clinical trials and a network meta-analysis. Pre-progression direct costs included the costs of Rd and VMP, treatment of adverse events (including prophylaxis) and routine care and monitoring associated with MM. Post-progression direct costs included costs of subsequent treatment(s) and routine care and monitoring for progressive disease, all obtained from published literature and estimated from a U.S. payer perspective. Utilities were obtained from the aforementioned trials. Costs and outcomes were discounted at 3% annually. RESULTS Relative to VMP, use of Rd was expected to result in an additional 2.22 LYs and 1.47 QALYs (discounted). Patients initiated with Rd were expected to incur an additional $78,977 in mean lifetime direct costs (discounted) vs those initiated with VMP. The incremental costs per QALY and per LY gained with Rd vs VMP were $53,826 and $35,552, respectively. In sensitivity analyses, results were found to be most sensitive to differences in survival associated with Rd vs VMP, the cost of lenalidomide and the discount rate applied to effectiveness outcomes. CONCLUSIONS Rd was expected to result in greater LYs and QALYs compared with VMP, with similar overall costs per LY for each regimen. Results of this analysis indicated that Rd may be a cost-effective alternative to VMP as initial treatment for transplant-ineligible patients with MM, with an incremental cost-effectiveness ratio well within the levels for recent advancements in oncology.
Collapse
Affiliation(s)
- S Z Usmani
- a a Levine Cancer Institute/Carolinas Healthcare System , Charlotte, NC , USA
| | - J D Cavenagh
- b b St. Bartholomew's Hospital , West Smithfield, London , UK
| | - A R Belch
- c c Cross Cancer Institute , University of Alberta , Edmonton, AB , Canada
| | - C Hulin
- d d Bordeaux Hospital University Center (CHU) , Bordeaux , France
| | - S Basu
- e e Royal Wolverhampton Hospitals NHS Trust , Wolverhampton , UK
| | - D White
- f f Dalhousie University and QEII Health Sciences Center , Halifax, NS , Canada
| | - A Nooka
- g g Winship Cancer Institute , Emory University , Atlanta , GA , USA
| | | | - W Yiu
- h h Celgene Corporation , Summit, NJ , USA
| | | | - A Berger
- i i Evidera , Lexington, MA , USA
| | | | - S Guo
- i i Evidera , Lexington, MA , USA
| | - G Binder
- h h Celgene Corporation , Summit, NJ , USA
| | - C J Gibson
- h h Celgene Corporation , Summit, NJ , USA
| | - T Facon
- j j Service des Maladies du Sang , Hôpital Huriez , CHRU Lille, Lille , France
| |
Collapse
|
11
|
Gibson CJ, Dixon BE, Abrams K. Convergent evolution of health information management and health informatics: a perspective on the future of information professionals in health care. Appl Clin Inform 2015; 6:163-84. [PMID: 25848421 DOI: 10.4338/aci-2014-09-ra-0077] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [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: 09/29/2014] [Accepted: 02/02/2015] [Indexed: 11/23/2022] Open
Abstract
Clearly defined boundaries are disappearing among the activities, sources, and uses of health care data and information managed by health information management (HIM) and health informatics (HI) professionals. Definitions of the professional domains and scopes of practice for HIM and HI are converging with the proliferation of information and communication technologies in health care settings. Convergence is changing both the roles that HIM and HI professionals serve in their organizations as well as the competencies necessary for training future professionals. Many of these changes suggest a blurring of roles and responsibilities with increasingly overlapping curricula, job descriptions, and research agendas. Blurred lines in a highly competitive market create confusion for students and employers. In this essay, we provide some perspective on the changing landscape and suggest a course for the future. First we review the evolving definitions of HIM and HI. We next compare the current domains and competencies, review the characteristics as well as the education and credentialing of both disciplines, and examine areas of convergence. Given the current state, we suggest a path forward to strengthen the contributions HIM and HI professionals and educators make to the evolving health care environment.
Collapse
Affiliation(s)
- C J Gibson
- Schulich School of Medicine & Dentistry, Western University , London, ON, CANADA
| | - B E Dixon
- Richard M. Fairbanks School of Public Health, Indiana University , Indianapolis, IN, USA ; Center for Biomedical Informatics, Regenstrief Institute, Inc. , Indianapolis, IN, USA ; Center for Health Information and Communication, Department of Veterans Affairs, Veterans Health Administration, Health Services Research and Development Service CIN 13-416, Richard L. Roudebush VA Medical Center , Indianapolis, IN, USA
| | - K Abrams
- Canadian College of Health Information Management , London, ON, CANADA
| |
Collapse
|
12
|
Abstract
OBJECTIVE The directional and temporal nature of relationships between overweight and obesity and hysterectomy with or without oophorectomy is not well understood. Overweight and obesity may be both a risk factor for the indications for these surgeries and a possible consequence of the procedure. We used prospective data to examine whether body mass index (BMI) increased more following hysterectomy with and without bilateral oophorectomy compared with natural menopause among middle-aged women. METHODS BMI was assessed annually for up to 10 years in the Study of Women's Health Across the Nation (SWAN (n=1962)). Piecewise linear mixed growth models were used to examine changes in BMI before and after natural menopause, hysterectomy with ovarian conservation and hysterectomy with bilateral oophorectomy. Covariates included education, race/ethnicity, menopausal status, physical activity, self-rated health, hormone therapy use, antidepressant use, age and visit before the final menstrual period (FMP; for natural menopause) or surgery (for hysterectomy/oophorectomy). RESULTS By visit 10, 1780 (90.6%) women reached natural menopause, 106 (5.5%) reported hysterectomy with bilateral oophorectomy and 76 (3.9%) reported hysterectomy with ovarian conservation. In fully adjusted models, BMI increased for all women from baseline to FMP or surgery (annual rate of change=0.19 kg m(-2) per year), with no significant differences in BMI change between groups. BMI also increased for all women following FMP, but increased more rapidly in women following hysterectomy with bilateral oophorectomy (annual rate of change=0.21 kg m(-2) per year) as compared with following natural menopause (annual rate of change=0.08 kg m(-2) per year, P=0.03). CONCLUSION In this prospective examination, hysterectomy with bilateral oophorectomy was associated with greater increases in BMI in the years following surgery than following hysterectomy with ovarian conservation or natural menopause. This suggests that accelerated weight gain follows bilateral oophorectomy among women in midlife, which may increase risk for obesity-related chronic diseases.
Collapse
Affiliation(s)
- C J Gibson
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA 15213, USA.
| | | | | | | | | |
Collapse
|
13
|
Abstract
Multiple endoscopic biopsy specimens of esophageal mucosa were received from a 13-year-old castrated male standard Poodle. The dog was presented for painful swallowing. Endoscopically, the distal aspect of the esophagus was inflamed with a polypoid mass that protruded into the esophageal lumen. Histologically, the stratified squamous epithelium overlying the mass and lining the adjacent esophageal mucosa was replaced by papillary projections covered by columnar epithelium with goblet cells supported by a fibrous stroma. This article reports a case of spontaneous esophageal adenomatous polyp with intestinal metaplasia (Barrett esophagus) and reviews the pathogenesis of esophageal metaplasia and adenocarcinoma.
Collapse
Affiliation(s)
- C J Gibson
- Department of Biomedical Sciences, Section of Pathology, Tufts University Cummings School of Veterinary Medicine, 200 Westboro Road, North Grafton, MA 01536, USA.
| | | | | | | |
Collapse
|
14
|
Gibson CJ, Weiss J, Goodrich M, Onega T. False-positive mammography and depressed mood in a screening population: findings from the New Hampshire Mammography Network. J Public Health (Oxf) 2009; 31:554-60. [PMID: 19574274 DOI: 10.1093/pubmed/fdp064] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND False positives occur in approximately 11% of screening mammographies in the USA and may be associated with psychologic sequelae. METHODS We sought to examine the association of false-positive mammography with depressed mood among women in a screening population. Using data from a state-based mammography registry, women who completed a standardized questionnaire between 7 May 2001 and 2 June 2003, a follow-up questionnaire between 19 June 2003 and 8 October 2004 and who received at least one screening mammogram during this interval were identified. False positives were examined in relation to depressed mood. RESULTS Eligibility criteria were met by 13 491 women with a median age of 63.9 (SD = 9.6). In the study population, 2107 (15.62%) experienced at least one false positive mammogram and 450 (3.34%) met criteria for depressed mood. Depressed mood was not significantly associated with false positives in the overall population [OR = 0.96; 95% confidence interval (CI) = 0.72-1.28], but this association was seen among Non-White women (OR = 3.23; 95% CI = 1.32-7.91). CONCLUSION Depressed mood may differentially affect some populations as a harm associated with screening mammography.
Collapse
Affiliation(s)
- C J Gibson
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA 15213, USA.
| | | | | | | |
Collapse
|
15
|
Brindle GW, Gibson CJ. Entropy as a measure of diversity in an inventory of medical devices. Med Eng Phys 2007; 30:399-401. [PMID: 17573228 DOI: 10.1016/j.medengphy.2007.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2006] [Revised: 05/02/2007] [Accepted: 05/03/2007] [Indexed: 11/27/2022]
Abstract
Quantitative techniques for the measurement of species diversity have been developed in ecological studies. One such technique, based on an entropy measurement, has been applied to the assessment of medical device diversity in large inventories of medical equipment. Using this technique it is possible to identify trends which are not apparent from simple considerations of the total number of devices, or the number of device types. Objective measurements of this type can be used to monitor the progress of planned equipment replacement programmes.
Collapse
Affiliation(s)
- G W Brindle
- Department of Medical Physics and Clinical Engineering, John Radcliffe Hospital, Oxford, UK
| | | |
Collapse
|
16
|
Abstract
Ca2+ oscillations are one of the most important signals within the cell. The mechanism for generation of Ca2+ oscillations is still not yet fully elucidated. We studied the role of capacitative Ca2+ entry (CCE) on intracellular Ca2+ oscillations induced by testosterone at the single-cell level in primary myotubes. Testosterone (100 nM) rapidly induced an intracellular Ca2+ rise, accompanied by Ca2+ oscillations in a majority of myotubes. Spectral analysis of the Ca2+ oscillations revealed a periodicity of 20.3 +/- 1.8 s (frequency of 49.3 +/- 4.4 mHz). In Ca(2+)-free medium, an increase in intracellular Ca2+ was still observed, but no oscillations. Neither nifedipine nor ryanodine affected the testosterone-induced Ca2+ response. This intracellular Ca2+ release was previously shown in myotubes to be dependent on inositol-1,4,5-trisphosphate (IP3). Intracellular Ca2+ store depletion in Ca(2+)-free medium, using a sarcoplasmic/endoplasmic reticulum calcium ATPase-pump inhibitor, followed by re-addition of extracellular Ca2+, gave a fast rise in intracellular Ca2+, indicating that CCE was present in these myotubes. Application of either testosterone or albumin-bound testosterone induced Ca2+ release and led to CCE after re-addition of Ca2+ to Ca(2+)-free extracellular medium. The CCE blockers 2-aminoethyl diphenylborate and La3+, as well as perturbation of the cytoskeleton by cytochalasin D, inhibited testosterone-induced Ca2+ oscillations and CCE. The steady increase in Ca2+ induced by testosterone was not, however, affected by either La3+ or cytochalasin D. These results demonstrate testosterone-induced Ca2+ oscillations in myotubes, mediated by the interplay of IP3-sensitive Ca2+ stores and Ca2+ influx through CCE.
Collapse
Affiliation(s)
- M Estrada
- Centro de Estudios Moleculares de la Célula and Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Casilla 70005, Santiago 6530499, Chile
| | | | | | | | | |
Collapse
|
17
|
Abstract
Quantitative assessment of radioactive contamination is a desirable aim in any department using radionuclides. Guidance is available for calibration of contamination monitors with sealed reference sources but the calibrations obtained in this way are of limited practical use. In this work, we examined methods for calibration using radionuclides used in the hospital workplace. Calibration factors (s-1 per Bq.cm-2) were obtained for 99mTc, 131I, 90Y and 89Sr for three types of monitor for a range of contamination areas, and minimum detectable activities were calculated. Of the three detectors evaluated, the Berthold LB122/LB6357F proved the most sensitive for all radionuclides tested. The effect of contamination area was found to be significant; calibration factors for a particular monitor varied by up to a factor of 4 with contamination area, which has important implications, for example in the estimation of skin doses. User departments need to be aware of this variation and how to correct for it.
Collapse
Affiliation(s)
- J MacDonald
- Medical Physics Department, Glan Clwyd Hospital, Bodelwyddan, Denbighshire, UK.
| | | |
Collapse
|
18
|
Abstract
The minimal-preparation, resin-retained adhesive bridge may be considered to be an ideal choice of fixed prosthesis to replace a single missing tooth, especially in the anterior maxillary region. The technique is well documented, enjoys a high success rate, and with suitable case selection generally employs a conservative preparation. Other advantages include reduced cost compared with conventional bridges and simplified laboratory and clinical procedures. Its limitations are principally due to occlusal factors, or the presence of unsuitable abutment teeth--for example, those that are extensively restored. Another traditional contraindication is the presence of diastemas, which may limit the potential aesthetic gains. This paper presents a series of case reports which describe an altered technique in order to maintain anterior spacing.
Collapse
|
19
|
Abstract
Nefiracetam, a pyrrolidone derivative, is a nootropic agent that has facilitated cognitive function in a wide variety of animal models of cognitive dysfunction. The purpose of this study was to investigate the efficacy of the chronic postinjury administration of nefiracetam (DM-9384) in improving cognitive performance following central fluid percussion brain injury in rats. Twenty-four hours following surgical preparation, a sham injury or a moderate fluid percussive injury (2.1 atm) was delivered. Nefiracetam was administered chronically (0 or 9 mg/kg, po, for sham animals and 0, 3, or 9 mg/kg for injured animals) on postinjury days 1-15. Cognitive performance was assessed using the Morris water maze (MWM) on postinjury days 11-15. Chronic administration of 3 and 9 mg/kg nefiracetam attenuated MWM deficits produced by central fluid percussive brain injury. Importantly, the MWM performance of the injured animals treated with 9 mg/kg did not significantly differ from uninjured, sham animals. The 9-mg/kg dose of nefiracetam did not have a positive or negative effect on MWM performance of uninjured animals. The results of the present experiment suggest that a nootropic such as nefiracetam may be an appropriate treatment for trauma-induced cognitive dysfunction.
Collapse
Affiliation(s)
- S M DeFord
- Department of Psychology, Virginia Commonwealth University, P.O. Box 842018, 808 West Franklin Street, Richmond, VA 23284-2018, USA.
| | | | | | | | | |
Collapse
|
20
|
Abstract
UNLABELLED Propofol has an antiemetic effect that may be mediated by gamma-aminobutyric acid (GABA) influences on the serotonin system, the mechanism of which is not known. We used three techniques, immunohistochemistry, High Performance Liquid Chromatography, and electrophysiology, to define propofol's effects on the rat's brainstem. Paired male Wistar rats received propofol, 20 mg/kg/hr, or Intralipid for 6 h. The brains were then subjected to immunohistochemical analysis of serotonin. In a separate experiment after a propofol or Intralipid infusion, cerebrospinal fluid (CSF) was extracted from the fourth ventricle and analyzed for the amount of serotonin and 5-hydroxyindoleacetic acid. Electrophysiological neuronal recordings were made in the area postrema (AP) in response to propofol with and without a GABA or serotonin antagonist. Results showed that immunohistochemical staining for serotonin in the propofol rats was significantly increased (28 +/- 12%) in the dorsal raphe and decreased in the AP (17 +/- 6%) compared with control. There were no significant changes in the isoflurane-anesthetized animals. Both serotonin and 5-hydroxyindoleacetic acid in the CSF of the fourth ventricle at the level of the AP were significantly reduced by 63% and 36%, respectively. Both propofol and pentobarbital injections reduce AP neuronal activity, but only the propofol response was blocked by bicuculline, a GABA antagonist. We conclude that the reduced levels of serotonin in the AP and the CSF may explain the antiemetic property of propofol. Propofol may also directly act on AP neurons via a GABA(A) receptor to reduce their activity. IMPLICATIONS Propofol may produce its antiemetic effect by depleting the area postrema of serotonin as well as by a direct gamma-aminobutyric acid-mediated inhibition.
Collapse
Affiliation(s)
- D F Cechetto
- Departments of Anatomy and Cell Biology and Physiology, University of Western Ontario, London, Ontario.
| | | | | | | |
Collapse
|
21
|
Abstract
Audiogenic seizure (AGS) activity can be induced in the seizure-resistant Long-Evans rat by postnatal priming. This study examined the effects of unilateral lesions of the inferior colliculus (IC) and implantation of tectal grafts on AGS components. Animals were primed with a 10-kHz tone burst at 120 dB on postnatal day 14 and tested for AGS susceptibility on day 28, and then two groups were unilaterally lesioned including animals receiving embryonic day 16-17 grafts of caudal tectum. Subsequently, animals were repeatedly tested for wild running and clonic-tonic convulsion components of AGS. The results demonstrate that unilaterally grafted animals with partial IC lesions showed significant reduction in the incidence of clonus expression with greater terminal uniphasic wild running behavior. These effects were stronger than in animals with comparable unilateral lesions alone. Many neurons in graft cases were in direct contact with host tissues to provide a substrate for tissue interactions previously demonstrated to promote neuron survival and remediate IC functions.
Collapse
Affiliation(s)
- J R Coleman
- Department of Psychology, University of South Carolina, Columbia 29208, USA
| | | | | | | |
Collapse
|
22
|
Gibson CJ. Meandering in Medical Physics: A Personal Account of Hospital Physics. Phys Med Biol 2000. [DOI: 10.1088/0031-9155/45/5/501] [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: 11/11/2022]
|
23
|
O'Dell DM, Gibson CJ, Wilson MS, DeFord SM, Hamm RJ. Positive and negative modulation of the GABA(A) receptor and outcome after traumatic brain injury in rats. Brain Res 2000; 861:325-32. [PMID: 10760494 DOI: 10.1016/s0006-8993(00)02055-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [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] [Indexed: 10/17/2022]
Abstract
Glutamate-mediated excitotoxicity has been shown to contribute to cellular dysfunction following traumatic brain injury (TBI). Increasing inhibitory function through stimulation of gamma-aminobutyric acid (GABA(A)) receptors may attenuate excitotoxic effects and improve outcome. The present experiment examined the effects of diazepam, a positive modulator at the GABA(A) receptor, on survival and cognitive performance in traumatically brain-injured animals. In experiment 1, 15 min prior to central fluid percussion brain injury, rats (n=8 per group) were injected (i.p.) with saline or diazepam (5 mg/kg or 10 mg/kg). Additional rats (n=8) were surgically prepared but not injured (sham-injury). Rats pre-treated with the 5 mg/kg dose of diazepam had significantly lower mortality (0%) than injured, saline-treated rats (53%). Also, diazepam-treated (5 mg/kg) rats had significantly shorter latencies to reach the goal platform in the Morris water maze test performed 11-15 days post-injury. In experiment 2, at 15 min post-injury, rats were given either saline (n=5) or 5 mg/kg diazepam (n=6). Rats treated with diazepam did not differ in mortality from injured rats treated with vehicle. However, rats treated with diazepam at 15 min post-injury had significantly shorter latencies to reach the goal platform in the Morris water maze than injured, vehicle-treated rats. In experiment 3, the post-injury administration of bicuculline (1.5 mg/kg, n=8), a GABA(A) antagonist, increased Morris water maze goal latencies compared to injured animals treated with saline (n=8). These results suggest that enhancing inhibitory function during the acute post-injury period produces beneficial effects on both survival and outcome following experimental TBI.
Collapse
Affiliation(s)
- D M O'Dell
- Department of Psychology, Virginia Commonwealth University, P.O. Box 842018, Richmond, VA 23284-2018, USA.
| | | | | | | | | |
Collapse
|
24
|
Abstract
Throughout the past decade much research has been directed towards identifying the occurrence, epidemiology, and risks associated with waterborne protozoa. While outbreaks are continually documented, sporadic cases of disease associated with exposure to low levels of waterborne protozoa are of increasing concern. Current methodologies may not be sensitive enough to define these low levels of disease. However, risk assessment methods may be utilised to address these low level contamination events. The purpose of this article is to provide an introduction to microbial risk assessment for waterborne protozoa. Risk assessment is a useful tool for evaluating relative risks and can be used for development of policies to decrease risks. Numerous studies have been published on risk assessment methods for pathogenic protozoa including Cryptosporidium and Giardia. One common notion prevails: microbial risk assessment presents interesting complications to the traditional chemical risk assessment paradigm. Single microbial exposures (non-threshold) are capable of causing symptomatic illness unlike traditional chemical exposures, which require a threshold to be reached. Due to the lack of efficient recovery and detection methods for protozoa, we may be underestimating the occurrence, concentration and distribution of these pathogenic micro-organisms. To better utilize the tool of microbial risk assessment for risk management practices, future research should focus in the area of exposure assessment.
Collapse
Affiliation(s)
- C J Gibson
- Department of Marine Science, University of South Florida, St. Petersburg 33701, USA.
| | | | | |
Collapse
|
25
|
Griffin DW, Gibson CJ, Lipp EK, Riley K, Paul JH, Rose JB. Detection of viral pathogens by reverse transcriptase PCR and of microbial indicators by standard methods in the canals of the Florida Keys. Appl Environ Microbiol 1999; 65:4118-25. [PMID: 10473424 PMCID: PMC99749 DOI: 10.1128/aem.65.9.4118-4125.1999] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.7] [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
In order to assess the microbial water quality in canal waters throughout the Florida Keys, a survey was conducted to determine the concentration of microbial fecal indicators and the presence of human pathogenic microorganisms. A total of 19 sites, including 17 canal sites and 2 nearshore water sites, were assayed for total coliforms, fecal coliforms, Escherichia coli, Clostridium perfringens, enterococci, coliphages, F-specific (F(+)) RNA coliphages, Giardia lamblia, Cryptosporidium parvum, and human enteric viruses (polioviruses, coxsackie A and B viruses, echoviruses, hepatitis A viruses, Norwalk viruses, and small round-structured viruses). Numbers of coliforms ranged from <1 to 1, 410, E. coli organisms from <1 to 130, Clostridium spp. from <1 to 520, and enterococci from <1 to 800 CFU/100 ml of sample. Two sites were positive for coliphages, but no F(+) phages were identified. The sites were ranked according to microbial water quality and compared to various water quality standards and guidelines. Seventy-nine percent of the sites were positive for the presence of enteroviruses by reverse transcriptase PCR (polioviruses, coxsackie A and B viruses, and echoviruses). Sixty-three percent of the sites were positive for the presence of hepatitis A viruses. Ten percent of the sites were positive for the presence of Norwalk viruses. Ninety-five percent of the sites were positive for at least one of the virus groups. These results indicate that the canals and nearshore waters throughout the Florida Keys are being impacted by human fecal material carrying human enteric viruses through current wastewater treatment strategies such as septic tanks. Exposure to canal waters through recreation and work may be contributing to human health risks.
Collapse
Affiliation(s)
- D W Griffin
- Department of Marine Sciences, University of South Florida, St. Petersburg, Florida 33701, USA
| | | | | | | | | | | |
Collapse
|
26
|
Gibson CJ, Munoz DG. Chromogranin A inhibits dopamine release from rat striatal slices. J Neural Transm (Vienna) 1999; 105:1083-9. [PMID: 9928879 DOI: 10.1007/s007020050113] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Chromogranin A (CGA), a prohormone and a protein component of endocrine and neural secretory granules, neuritic plaques in Alzheimer's disease and Lewy bodies in Parkinson's disease, inhibited the release of dopamine (DA) from perfused rat striatal slices. Dopamine release was stimulated by a pulse of high potassium (40mM) medium introduced at 20 minutes (K1) and 55 minutes (K2) following equilibration. The ratio of K2/K1 was 0.80+/-0.04 in control tissues, but fell significantly to 0.26+/-0.08 when 100nM purified CGA was added prior to the second potassium pulse. This reduction in DA release was equivalent to that seen when calcium was excluded from the buffer (0.19+/-0.05). Pancreastatin, a centrally active peptide product of CGA, had no effect on stimulated DA release (0.77+/-0.06), although it, as well as the other treatments, did reduce basal DA release. It is likely that the parent molecule itself, CGA, or an as yet unidentified product is responsible for inhibition of K-stimulated striatal DA release.
Collapse
Affiliation(s)
- C J Gibson
- Department of Pathology, The University of Western Ontario, London, Canada
| | | |
Collapse
|
27
|
MacDonald J, Gibson CJ, Fish PJ, Assinder DJ. The significance of variations in the angular correction factor in in situ gamma spectrometry. J Radiol Prot 1998; 18:37-42. [PMID: 9594115 DOI: 10.1088/0952-4746/18/1/006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In situ gamma spectrometry is a powerful method of assessing radioactive contamination in soil. The most widely adopted calibration methodology relates the overall sensitivity of the detector system to the product of three calibration factors: (a) the flux at the detector per unit activity in the ground phi/S(A), (b) the detected count-rate per unit flux incident normally at the detector N0/phi and (c) a correction factor to take into account the angular non-uniformity in response of the detector (Nf/N0). The dependence of the latter factor on the activity distribution with soil depth is generally neglected despite the lack of published evidence to support this. By (i) modelling and (ii) use of published experimental profiles, this work examines the range of Nf/N0 values likely to be encountered in the field. It was found that the use of a fixed angular correction factor is justified given that the maximum errors in the derived activity concentration do not exceed 5% and are far outweighed by other uncertainties.
Collapse
Affiliation(s)
- J MacDonald
- The North Wales Medical Physics and Clinical Engineering Service, Glan Clwyd Hospital, Bodelwyddan, Denbighshire, UK
| | | | | | | |
Collapse
|
28
|
Abstract
Rats with medial prefrontal cortex or sham control lesions were tested on an eight-arm radial maze task to examine memory for the temporal order of a variable and a constant sequence of spatial locations as a function of temporal distance. During the study phase of each trial, rats were allowed to visit each of eight arms once in an order that was randomly selected or fixed for that trial. The test phase required the rats to choose which of two arms occurred earlier in the sequence of arms visited during the study phase. The arms selected as test arms varied according to temporal distance (0, 2, 4, or 6) or the number of arms that occurred between the two test arms in the study phase. For the variable sequences based on new information, control rats showed an increasing temporal distance function. Relative to control rats, medial prefrontal cortex-lesioned rats displayed a temporal order memory deficit across all distances. For the constant sequence based on familiar information, control rats performed well across all distances. Relative to controls, the medial prefrontal cortex-lesioned rats displayed a performance deficit. The results support the idea that the medial prefrontal cortex contributes to mnemonic operations associated with temporal order for new and familiar spatial location information.
Collapse
Affiliation(s)
- A A Chiba
- Department of Psychology, University of Utah, Salt Lake City 84112, USA
| | | | | |
Collapse
|
29
|
Abstract
The development of heterotopic ossification (HO) as a complication of toxic epidermal necrolysis (TEN) has not been previously reported. TEN, also known as Lyell's syndrome, is a rare but serious skin disorder that typically occurs after the administration of drugs, especially sulfonamides, barbiturates, phenytoin, and nonsteroidal anti-inflammatory agents. TEN is characterized by the development of large fluid-filled bullae with separation of large sheets of skin. Complications of TEN can include extensive denudation of skin with dehydration and electrolyte abnormalities, gastrointestinal hemorrhage, acute tubular necrosis, secondary infection of denuded skin, pneumonia, bacterial conjunctivitis, keratitis, and septic infarcts of internal organs. We report a case of HO in a patient with TEN after treatment with trimethoprim-sulfamethoxazole. A 49-year-old man developed an erythematous rash, bullae, fever, and extensive skin loss consistent with a diagnosis of TEN. He was intubated for complications of TEN (pneumonia) and maintained on bed rest for several weeks. In addition, he developed HO that resulted in multiple joint contractures. He was treated with aggressive range of motion by physical therapy, surgical resection of the HO followed by radiation to both elbows, right hip, and right knee. Postoperative outpatient rehabilitation enabled improved function in his mobility and activities of daily living. HO is known to occur after spinal cord and brain injuries and burns. It has not been reported to occur after TEN. Our experience with this case suggests that HO may merit inclusion into the list of complications of TEN.
Collapse
Affiliation(s)
- C J Gibson
- Department of Physical Medicine and Rehabilitation, School of Medicine and Dentistry, University of Rochester, NY, USA
| | | |
Collapse
|
30
|
Abstract
Stimulation of the ventral subiculum of the hippocampus activates the hippocampal-accumbens pathway and increases locomotor activity. Dopaminergic terminals in the nucleus accumbens have also been implicated in initiation of locomotor activity, and the release of dopamine in the nucleus accumbens is critical for locomotor responses initiated from the subiculum to occur. We have demonstrated release of dopamine in the nucleus accumbens using in vivo microdialysis after stimulation of the ventral subiculum with NMDA. Extracellular dopamine level in the nucleus accumbens was significantly increased by 40% over baseline as a result of NMDA stimulation of the ventral subiculum. This stimulation also caused more than a 40-fold increase in horizontal activity and total distance covered by the rats. Injection of saline into the subiculum caused neither a change in the dopamine level nor an increase in animal's activity. The dynamics of the measured changes in dopamine overflow correlated with the time course of locomotor changes. The results demonstrate that stimulation of the ventral subiculum causes release of dopamine in the nucleus accumbens which parallels the increase in locomotor activity.
Collapse
Affiliation(s)
- S M Brudzynski
- Department of Clinical Neurological Sciences, University of Western Ontario, London, Canada
| | | |
Collapse
|
31
|
Poduri KR, Cushman LA, Gibson CJ. Inpatient rehabilitation: the correlation between functional gains and appropriateness of admissions. Int J Rehabil Res 1996; 19:327-32. [PMID: 8982803] [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: 02/03/2023]
Abstract
All admissions to an acute rehabilitation unit were later critiqued by the rehabilitation team to determine appropriateness of admissions. The physiatrist alone evaluated the patient for admission. From the team which worked with the patient, a physical therapist, occupational therapist and a nurse were asked to evaluate the appropriateness of the admission; a decision on appropriateness had to be supported by at least two of these three. The team scored patients with the Functional Independence Measure (FIM) on admission, weekly, and at discharge. In a six-month period there were 60 appropriate admissions and ten inappropriate admissions. The average length of stay was 38.3 days for appropriate and 17.3 days for inappropriate admissions. The appropriate gorup had an average initial FIM score of 40.6 and discharge score of 66.6. The inappropriate group started with high FIM scores, with an average of 61.0, and did not significantly improve their scores. Their average discharge score was 70.0. The rate of progress (efficiency ratio), in points per day, was 0.81 for the appropriate and 0.36 for the inappropriate group. Thus, there is a strong positive correlation between the rate of progress and appropriateness as assessed at discharge by the multidisciplinary team [corrected].
Collapse
Affiliation(s)
- K R Poduri
- Department of Orthopedics, Strong Memorial Hospital University of Rochester, NY, USA
| | | | | |
Collapse
|
32
|
Diffey BL, Gibson CJ, Haylock R, McKinlay AF. Outdoor ultraviolet exposure of children and adolescents. Br J Dermatol 1996; 134:1030-4. [PMID: 8763419] [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: 02/02/2023]
Abstract
The weekday and weekend outdoor ultraviolet exposure of young people from primary and secondary schools in three geographically distinct regions of England was determined over a 3-month period in summer. Ultraviolet exposure was measured using personal film badges worn by each young person, and time spent outdoors, in hourly intervals, assessed using exposure records. In each area a class of 9-10-year-old children from a primary school and a class of 14-15-year-old adolescents from a secondary school took part, giving a total of 180 subjects. We found that primary school children received higher outdoor ultraviolet exposure than young people in secondary schools, and geographical differences in exposure could not be accounted for solely by differences in ambient ultraviolet. There was little difference between the exposure of males and females. Children and adolescents did not behave as homogeneous groups with regard to exposure.
Collapse
Affiliation(s)
- B L Diffey
- Regional Medical Physics Department, Dryburn Hospital, Durham, U.K
| | | | | | | |
Collapse
|
33
|
Affiliation(s)
- M J Ablett
- Department of Radiology, Royal Victoria Infirmary, Newcastle-upon-Tyne, United Kingdom
| | | | | |
Collapse
|
34
|
Poduri KR, Palenski C, Gibson CJ. Inpatient rehabilitation: physiatric and nurse practitioner admission assessment of stroke patients and their rehabilitation outcomes. Int J Rehabil Res 1996; 19:111-21. [PMID: 8842825] [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: 02/02/2023]
Abstract
The purpose of this study was to compare outcomes in stroke patients with two different methods of admission to an inpatient unit. Patients' outcomes were studied for 3 years. Admission screening was performed either by a physiatrist (group I, n = 93) or by a nurse practitioner (group II, n = 100). All admission decisions were made solely by the physiatrist. The outcome measures used were appropriateness of admission, discharge to home versus nursing home and functional gains measured on the Functional Independence Measure. The average length of stay was 28 days for group 1 patients and 29 days for group II. Ninety-seven per cent of group I and 94% of group II patients were considered appropriate for admission. The difference is not statistically significant (Z = 1.02). Ninety-six per cent of patients in each group were discharged home. Ninety-six per cent of group I and 89% of group II patients met the functional goals. Group I fared better than group II, and the difference between the groups (Z = 1.85) is statistically significant at p < 0.04.
Collapse
Affiliation(s)
- K R Poduri
- Department of Orthopedics, University of Rochester, NY, USA
| | | | | |
Collapse
|
35
|
Abstract
Bilateral intranigral administration of the selective NK-1 tachykinin receptor agonist [AcArg6, Sar9, Met(O2)11]SP6-11 (0-1 nmol total bilateral dose) selectively induced grooming in rats. This response was blocked by concurrent intranigral administration of the NK-1 tachykinin receptor antagonist RP 67580 (2 nmol), but not by NK-2 (L-659,877) or NK-3 ([Trp7, beta-Ala8]NKA4-10) antagonists. Pretreatment with systemic opioid (naloxone 1.5 mg/kg) and D1 dopamine (SCH 23390 100 micrograms/kg) receptor antagonists also attenuated tachykinin-induced grooming, which was unaffected by D2 dopamine (sulpiride 30 mg/kg) or 5-HT2A+C (ritanserin 2 mg/kg) antagonists. Grooming induced by intranigral [AcArg6, Sar9, Met(O2)11]SP6-11 was also attenuated by bilateral 6-hydroxydopamine lesions of the substantia nigra. These findings indicate that grooming induced by intranigral tachykinins reflects activation of NK-1 receptors and is dependent upon endogenous dopamine and consequent selective stimulation of D1 dopamine receptors.
Collapse
Affiliation(s)
- A J Stoessl
- Clinical Neurological Sciences, University of Western Ontario, London, Canada.
| | | | | | | |
Collapse
|
36
|
Gibson CJ, Opalka PC, Moore CA, Brady RS, Mion LC. Effectiveness of bran supplement on the bowel management of elderly rehabilitation patients. J Gerontol Nurs 1995; 21:21-30. [PMID: 7594246 DOI: 10.3928/0098-9134-19951001-06] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
1. Constipation is a common problem in the elderly that affects up to 20% of those 65 years and older. 2. Patients receiving the fiber supplement had a significantly lower number of bowel agents per day as compared to the control patients. 3. Side effects from the additional fiber occurred in a subgroup of patients; thus, institution of additional fiber to the diets of ill, physically dependent patients is best done gradually and with close monitoring.
Collapse
|
37
|
Abstract
A survey, using a postal questionnaire, was carried out to examine the current practice of UVB phototherapy in dermatology centres in the U.K. The questionnaire was sent to 115 dermatology departments, and sought information regarding the type and age of each machine used for ultraviolet B (UVB) phototherapy, methods of prescribing, recording and terminating patient exposure, and the skin conditions treated. Completed questionnaires were received from 87 of the 115 centres, giving a response rate of 76%. The survey showed that an appreciable number of U.K. phototherapy centres are using equipment which is both old, and suboptimal in producing a therapeutic response. There appeared to be a wide variation in the approach to phototherapy, both in terms of prescribing initial and incremental exposure, and in terminating treatment. The findings suggest that effectiveness and efficiency might be improved, and the risk/benefit ratio of phototherapy further reduced, by some rationalization of treatment protocols.
Collapse
Affiliation(s)
- G Dootson
- Department of Dermatology, Addenbrooke's Hospital, Cambridge, U.K
| | | | | | | |
Collapse
|
38
|
Gibson CJ, Diffey BL, Chandler ST. Posterior view imaging in pulmonary embolism. Nucl Med Commun 1994; 15:306. [PMID: 7993429 DOI: 10.1097/00006231-199404000-00165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
|
39
|
Abstract
Chromogranin A (CGA), a peripherally active prohormone, is a soluble component in the secretory granules of many endocrine tissues and is cosecreted with their peptide or amine hormones. Using an antibody prepared against purified rat adrenal CGA, immunostaining was localized to the inner and outer plexiform layers of the rat retina and to selected ganglion cells. Exogenous CGA (purified from human adrenals) when applied to perfused rat retina potently inhibited the potassium-induced release of endogenous dopamine (DA). This action was dose-dependent, with an IC50 of 3 nM; at 100 nM CGA retinal DA release was completely abolished.
Collapse
Affiliation(s)
- C J Gibson
- Department of Pathology, University of Western Ontario, London, Canada
| | | |
Collapse
|
40
|
Abstract
Many image enhancement algorithms can be implemented by convoluting the image with a predefined kernel function. A class of such functions is identified which has the property that a two-dimensional convolution can be exactly implemented using two successive one-dimensional convolutions along the rows and columns of the image. This leads to a simple and rapid algorithm for image enhancement, which can be applied to implement both low pass and high pass filters. The technique enables large convolution masks to be used without excessive computation time and without the need for large intermediate storage arrays. This approach facilitates the interactive processing of high resolution digital medical images.
Collapse
Affiliation(s)
- C J Gibson
- Regional Medical Physics Department, Dryburn Hospital, Durham, U.K
| |
Collapse
|
41
|
Abstract
Endogenous dopamine (DA) release was measured in perfused rat retinae. Perfusion with elevated potassium (40 mM K) resulted in a 5-6-fold increase in DA release over baseline or 11.6 +/- 0.9% of final tissue DA content. When the selective DA D2 receptor agonist quinpirole was added to the perfusion medium (at 1 and 10 microM), K-stimulated DA release was significant decreased compared to controls (to 7.0 +/- 1.6 and 6.14 +/- 1.4%, respectively). Addition of the D2 antagonist (+/-)-sulpiride (10 microM) significantly increased DA release to 19.1 +/- 1.3%. DA could be released with successive pulses of K; an initial 10 min pulse resulted in a 4-5-fold increase in endogenous DA release over basal levels or 11.4% of the final retinal tissue DA content and a 3-fold increase (a 9.3% fractional release) upon a second K stimulation given 50 min later. The ratio of stimulated DA release during the two K pulses was 0.82 +/- 0.04. When L-tyrosine (100 microM) was included in the medium throughout the perfusion, K2/K1 was increased to 1.14 +/- 0.13. Both tissue DA level and release were decreased by the tyrosine hydroxylase inhibitor, alpha-methyl-p-tyrosine (AMPT). At 10 microM AMPT K-stimulated DA release was reduced by 50% during the first pulse and completely abolished during the second K pulse. At 100 microM both basal and K-stimulated release were significantly reduced. Exposure of dark-adapted retinae to light in L-tyrosine-supplemented perfusion medium resulted in an increased release of DA compared to retinae perfused with tyrosine-free medium.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- C J Gibson
- Department of Pathology, University of Western Ontario, London, Canada
| |
Collapse
|
42
|
Gibson CJ. Gamma-camera linearity and resolution assessed using coarsely sampled line spread functions. Phys Med Biol 1992. [DOI: 10.1088/0031-9155/37/2/005] [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: 11/11/2022]
|
43
|
Gibson CJ. Distinguished Member Award. Oper Dent 1990; 15:228-9. [PMID: 2095536] [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: 12/30/2022]
|
44
|
Gibson CJ. Patterns of care for stroke survivors. Stroke 1990; 21:II38-9. [PMID: 2399549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- C J Gibson
- Department of Preventive and Rehabilitation Medicine, University of Rochester Medical Center, N.Y. 14642
| |
Collapse
|
45
|
Chandler ST, Gibson CJ, Elliott L. Models of renal blood flow and their use in the detection of renal artery stenosis. Nucl Med Commun 1990; 11:427-36. [PMID: 2200991] [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: 12/30/2022]
Abstract
First-pass studies of renal blood flow using 99Tcm-DTPA have been analysed in normotensive patients and those with renal artery stenosis. One and two component models of renal blood flow were examined for their ability to discriminate between these two groups. Using a two component model, 5/7 kidneys with proven renal artery stenosis were identified, with 38/40 kidneys in normotensive patients lying within the defined normal range. The two kidneys not detected by this technique both had extremely poor function. This model was also applied to other hypertensive patients referred for routine screening and appears promising in increasing the specificity of the 99Tcm-DTPA study for detecting renal artery stenosis.
Collapse
Affiliation(s)
- S T Chandler
- Regional Medical Physics Department, Memorial Hospital, Darlington, UK
| | | | | |
Collapse
|
46
|
Abstract
A simple superperfusion apparatus for measuring endogenous dopamine (DA) release from rat retina is described. DA release is stimulated by increasing levels of potassium (K) in the superfusion medium and this K-stimulated release is calcium dependent. Exposure of dark-adapted retinae to light also increases endogenous DA release. This system should prove useful in determining what factors may control endogenous DA release in the retina.
Collapse
Affiliation(s)
- C J Gibson
- Department of Pathology, University of Western Ontario, London, Canada
| |
Collapse
|
47
|
Gibson CJ, Jago J, King AC, Knight AC, Kotre CJ, Williams ED. Exchange of nuclear medicine image files. Nucl Med Commun 1990; 11:332-3. [PMID: 2362746] [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: 12/31/2022]
|
48
|
Gibson CJ. Evaluation of shading algorithms for surface display: depth information, surface orientation, colour and transparency. Med Inform (Lond) 1989; 14:97-108. [PMID: 2787883 DOI: 10.3109/14639238908994983] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
When interpreting a shaded surface image the observer must infer a three-dimensional shape from a two-dimensional image. The principal monocular cues used in this process are surface orientation and apparent depth. Four shading algorithms were compared, ranging from pure depth to pure surface orientation with two intermediates. Eight observers assessed these algorithms using 40 sets of images showing test objects derived from emission computed axial tomograms, X-ray computed tomograms and simulated data. The results demonstrated a highly significant preference (p less than 0.01) for surface orientation over depth information for all observers and both imaging modalities. The coefficient of concordance showed that the observers were in good agreement as to the rank order of the algorithms, with significant agreement (p less than 0.05) for 37 of the 40 sets of images. The overall preferred algorithm was based on a local polynomial fitting procedure and contained primarily surface information. This shading algorithm was extended to include colour, which was used both as an arbitrary surface property to identify parts of a complex object and as a means of conveying temporal information. Further extension of the algorithm to the display of transparent surfaces was facilitated by an illumination model based on purely isotropic light. This enabled even irregular surfaces to be displayed as transparent objects, and was combined with opaque shading for displaying nested surfaces in nuclear magnetic resonance data.
Collapse
Affiliation(s)
- C J Gibson
- Regional Medical Physics Department, Dryburn Hospital, Durham, UK
| |
Collapse
|
49
|
Abstract
The radioactive gas 133Xe is widely used for ventilation imaging. This paper describes a system for continuous monitoring of the air concentration of 133Xe. The instrument consisted of a sodium iodide scintillation detector, a scaler/ratemeter and a data logger. The crystal was mounted inside a lead shield and enclosed in a perspex cylinder. A fan at one end of the cylinder drew room air into a shielded active volume via an inlet aperture designed to generate turbulent flow with no stagnant areas. The instrument was rendered relatively insensitive to external radiation by positioning the energy window over the 31 keV peak in the 133Xe spectrum. The detector sensitivity was approximately 2 s-1 per MBq m-3, with a typical background count rate of 0.12 s-1. The system was therefore capable of detecting a concentration of 0.06 MBq m-3 in a one-minute sampling interval. Results collected at five centres demonstrated that the eight-hour time-averaged concentrations were much less than the derived air concentration (DAC) for occupationally exposed persons (mean values 0.4 to 1.5% of the DAC), but that transient concentrations were extremely variable (mean values 7 to 24% of the DAC).
Collapse
Affiliation(s)
- E F Meanwell
- Regional Medical Physics Department, Dryburn Hospital, Durham, UK
| | | | | | | |
Collapse
|
50
|
Abstract
Retinal tyrosine level is correlated not only to its serum concentration, but also to the serum tyrosine ratio (the ratio of serum tyrosine to the sum of 5 neutral amino acids, leucine, isoleucine, valine, tryptophan and phenylalanine which compete with it for tissue uptake). In control animals, serum tyrosine ratio, retinal tyrosine, dopamine (DA) and its metabolites, and DOPA synthesis exhibit roughly parallel daily rhythms with night-time lows and peak levels occurring in the early portion of the daily light phase (L + 4 HR). In rats made diabetic by streptozotocin injection serum leucine, isoleucine and valine are elevated, lowering the serum tyrosine ratio and retinal tyrosine level by about 50% throughout the daily cycle. Parameters of DA turnover are still highest in the light phase but normal peak levels are delayed by 4 h until the latter half of the light phase (L + 8 HR). In diabetic rats, the normal increase in retinal DA synthesis and release upon exposure to light may be compromised by the decreased availability of its precursor, tyrosine.
Collapse
Affiliation(s)
- C J Gibson
- Department of Pathology, University of Western Ontario, London, Canada
| |
Collapse
|