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Deleuran M, Dézfoulian B, Elberling J, Knutar I, Lapeere H, Lossius AH, Schuttelaar MLA, Stockman A, Wikström E, Bradley M, de Bruin-Weller M, Gutermuth J, Mandelin JM, Schmidt MC, Thyssen JP, Vestergaard C. Systemic anti-inflammatory treatment of atopic dermatitis during conception, pregnancy and breastfeeding: Interdisciplinary expert consensus in Northern Europe. J Eur Acad Dermatol Venereol 2024; 38:31-41. [PMID: 37818828 DOI: 10.1111/jdv.19512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 08/09/2023] [Indexed: 10/13/2023]
Abstract
Treating atopic dermatitis (AD) in pregnant or breastfeeding women, and in women and men with AD aspiring to be parents is difficult and characterized by uncertainty, as evidence to inform decision-making on systemic anti-inflammatory treatment is limited. This project mapped consensus across dermatologists, obstetricians and patients in Northwestern Europe to build practical advice for managing AD with systemic anti-inflammatory treatment in men and women of reproductive age. Twenty-one individuals (sixteen dermatologists, two obstetricians and three patients) participated in a two-round Delphi process. Full consensus was reached on 32 statements, partial consensus on four statements and no consensus on four statements. Cyclosporine A was the first-choice long-term systemic AD treatment for women preconception, during pregnancy and when breastfeeding, with short-course prednisolone for flare management. No consensus was reached on second-choice systemics preconception or during pregnancy, although during breastfeeding dupilumab and azathioprine were deemed suitable. It may be appropriate to discuss continuing an existing systemic AD medication with a woman if it provides good disease control and its benefits in pregnancy outweigh its risks. Janus kinase (JAK) inhibitors, methotrexate and mycophenolate mofetil should be avoided by women during preconception, pregnancy and breastfeeding, with medication-specific washout periods advised. For men preconception: cyclosporine A, azathioprine, dupilumab and corticosteroids are appropriate; a 3-month washout prior to conception is desirable for methotrexate and mycophenolate mofetil; there was no consensus on JAK inhibitors. Patient and clinician education on appropriate (and inappropriate) AD treatments for use in pregnancy is vital. A shared-care framework for interdisciplinary management of AD patients is advocated and outlined. This consensus provides interdisciplinary clinical guidance to clinicians who care for patients with AD before, during and after pregnancy. While systemic AD medications are used uncommonly in this patient group, considerations in this article may help patients with severe refractory AD.
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Affiliation(s)
- M Deleuran
- Department of Dermatology, Aarhus University Hospital and Aarhus University, Aarhus, Denmark
| | - B Dézfoulian
- Dermatology Department, Liège University Hospital, Liège, Belgium
| | - J Elberling
- Department of Dermatology and Allergy, Department of Clinical Medicine, Herlev and Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark
| | - I Knutar
- Department of Dermatology, Vaasa Central Hospital, Vaasa, Finland
| | - H Lapeere
- Department of Dermatology, Ghent University Hospital, Ghent, Belgium
| | - A H Lossius
- Department of Dermatology, Oslo University Hospital, Oslo, Norway
| | - M L A Schuttelaar
- Department of Dermatology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - A Stockman
- Department of Dermatology, AZ Delta, Torhout, Belgium
| | - E Wikström
- Dermatology Health Clinic, Oulu, Finland
| | - M Bradley
- Dermatology and Venereology Unit, Department of Medicine Solna, Karolinska Institutet and Karolinska University Hospital, Solna, Sweden
| | - M de Bruin-Weller
- Department of Dermatology/Allergology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - J Gutermuth
- Vrije Universiteit Brussel (VUB), SKIN Research Group, Department of Dermatology, Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium
| | - J M Mandelin
- Department of Dermatology, Helsinki University Central Hospital, Helsinki, Finland
| | - M C Schmidt
- Department of Obstetrics and Gynecology, Aarhus University Hospital, Aarhus, Denmark
| | - J P Thyssen
- Department of Dermatology and Venereology, Bispebjerg Hospital, Copenhagen, Denmark
| | - C Vestergaard
- Department of Dermatology, Aarhus University Hospital and Aarhus University, Aarhus, Denmark
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Vermeersch G, Cruyt N, D'Hondt E, Geers J, Hertveldt K, Stockman A, Lambrecht G. Granulomatous peritoneal disease associated with oxaliplatin-based chemotherapy for ampullary adenocarcinoma: a case report. Acta Gastroenterol Belg 2023; 86:499-501. [PMID: 37814569 DOI: 10.51821/86.3.11323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/11/2023]
Abstract
Adenocarcinomas of the ampulla of Vater represent only 0.2% of all gastrointestinal cancers. Due to the low incidence no large clinical trials evaluating efficacy of treatments are available. Adjuvant therapy is often administered in patients with stage IB or higher. Oxaliplatin is considered as an effective and well tolerated therapeutic option. Adverse events associated with this therapy include cardio-, neuro-, nephrotoxicity and myelosuppression. Previously granulomatous pulmonary and liver manifestations have been described in oxaliplatin-based chemotherapy. In this report peritoneal manifestation of granulomatous disease associated with oxaliplatin is described for the first time. Sarcoidlike reactions may be misinterpreted as tumour progression or metastatic disease, and may consequently result in over-treatment.
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Affiliation(s)
- G Vermeersch
- Department of Gastroenterology and Digestive Oncology, AZ Damiaan, Oostende, Belgium
- Department of Internal Medicine, University Hospitals Leuven, Leuven, Belgium
| | - N Cruyt
- Department of Gastroenterology and Digestive Oncology, AZ Damiaan, Oostende, Belgium
- Department of Internal Medicine, University Hospitals Leuven, Leuven, Belgium
| | - E D'Hondt
- Department of Nuclear Medicine, AZ Damiaan, Oostende, Belgium
| | - J Geers
- Department of General and Abdominal Surgery, AZ Damiaan, Oostende, Belgium
| | - K Hertveldt
- Department of Anatomopathology, AZ Damiaan, Oostende, Belgium
| | - A Stockman
- Department of Radiology, AZ Damiaan, Oostende, Belgium
| | - G Lambrecht
- Department of Gastroenterology and Digestive Oncology, AZ Damiaan, Oostende, Belgium
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Stockman A, Belpaire A, Hadshiew IM, Žemličkova M, Vergou T, Navarro Triviño F, Márquez García A, Vasco M, Vazharova BK, Carballido F. Dermo-cosmetic spray containing Rhealba oat plantlets and Uncaria tomentosa extract in patients with mild-to-moderate cutaneous pain. J Eur Acad Dermatol Venereol 2022; 36 Suppl 4:3-11. [PMID: 35174562 DOI: 10.1111/jdv.17876] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/30/2021] [Accepted: 12/14/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND Chronic cutaneous pain has a substantial negative impact on quality of life (QoL). Dermo-cosmetics can support therapies for treatment of chronic skin diseases, providing symptomatic relief from chronic cutaneous pain and improved QoL. OBJECTIVES To assess the global tolerance and efficacy of a dermo-cosmetic spray containing Rhealba® Oat Plantlet and Uncaria tomentosa extracts in reducing cutaneous pain when used as a monotherapy or in association with drug or dermo-cosmetic treatments in patients with an underlying skin pathology. METHODS Patients aged ≥1 month with a cutaneous pain level ≥3 and an underlying skin pathology were provided with the spray to use up to six times daily for 6-8 weeks. Immediate effect on cutaneous pain and patient satisfaction were assessed after the first application. Global efficacy and tolerance, reduction in symptoms, improvement in QoL, pain reduction and patient overall satisfaction were assessed after 6-8 weeks. RESULTS Immediately after the first application, significant reductions in cutaneous pain were observed across all age groups (P < 0.0001), with 94% of patients reporting a reduction in pain. After 6-8 weeks, global tolerance was rated 'very good' or 'good' for 97% of patients, and the spray was efficacious in 95% of patients. Patient satisfaction with the efficacy of the spray was 95%. QoL scores improved in 86% and 94% of patients aged ≥12 and <12 years, respectively. Findings were similar across underlying pathology and therapy types (monotherapy or in association with another therapy). CONCLUSIONS The spray was well-tolerated and efficacious in providing symptom relief in patients with mild-to-moderate cutaneous pain, irrespective of the underlying pathology or therapy type.
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Affiliation(s)
| | | | | | - M Žemličkova
- General University Hospital in Prague (VFN), Prague, Czech Republic
| | - T Vergou
- Dermatology Experts, Chalandri, Greece
| | | | | | - M Vasco
- Hospital Lusiadas Lisboa, Lisbon, Portugal
| | | | - F Carballido
- Laboratoires A-Derma, Pierre Fabre Dermo-Cosmétique, Lavaur, France
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Voigt AP, Whitmore SS, Mulfaul K, Chirco KR, Giacalone JC, Flamme-Wiese MJ, Stockman A, Stone EM, Tucker BA, Scheetz TE, Mullins RF. Bulk and single-cell gene expression analyses reveal aging human choriocapillaris has pro-inflammatory phenotype. Microvasc Res 2020; 131:104031. [PMID: 32531351 DOI: 10.1016/j.mvr.2020.104031] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [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: 04/23/2020] [Revised: 06/02/2020] [Accepted: 06/05/2020] [Indexed: 12/17/2022]
Abstract
The human choroidal vasculature is subject to age-related structural and gene expression changes implicated in age-related macular degeneration (AMD). In this study, we performed both bulk and single-cell RNA sequencing on infant (n = 4 for bulk experiments, n = 2 for single-cell experiments) and adult (n = 13 for bulk experiments, n = 6 for single-cell experiments) human donors to characterize how choroidal gene expression changes with age. Differential expression analysis revealed that aged choroidal samples were enriched in genes encoding pro-inflammatory transcription factors and leukocyte transendothelial cell migration adhesion proteins. Such genes were observed to be differentially expressed specifically within choroidal endothelial cells at the single-cell level. Immunohistochemistry experiments support transcriptional findings that CD34 is elevated in infant choriocapillaris endothelial cells while ICAM-1 is enriched in adults. These results suggest several potential drivers of the pro-inflammatory vascular phenotype observed with advancing age.
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Affiliation(s)
- Andrew P Voigt
- Department of Ophthalmology and Visual Sciences, the University of Iowa Carver College of Medicine, Iowa City, IA 52242, United States of America; Institute for Vision Research, the University of Iowa, Iowa City, IA 52242, United States of America
| | - S Scott Whitmore
- Department of Ophthalmology and Visual Sciences, the University of Iowa Carver College of Medicine, Iowa City, IA 52242, United States of America; Institute for Vision Research, the University of Iowa, Iowa City, IA 52242, United States of America
| | - Kelly Mulfaul
- Department of Ophthalmology and Visual Sciences, the University of Iowa Carver College of Medicine, Iowa City, IA 52242, United States of America; Institute for Vision Research, the University of Iowa, Iowa City, IA 52242, United States of America
| | - Kathleen R Chirco
- Department of Ophthalmology and Visual Sciences, the University of Iowa Carver College of Medicine, Iowa City, IA 52242, United States of America; Institute for Vision Research, the University of Iowa, Iowa City, IA 52242, United States of America
| | - Joseph C Giacalone
- Department of Ophthalmology and Visual Sciences, the University of Iowa Carver College of Medicine, Iowa City, IA 52242, United States of America; Institute for Vision Research, the University of Iowa, Iowa City, IA 52242, United States of America
| | - Miles J Flamme-Wiese
- Department of Ophthalmology and Visual Sciences, the University of Iowa Carver College of Medicine, Iowa City, IA 52242, United States of America; Institute for Vision Research, the University of Iowa, Iowa City, IA 52242, United States of America
| | - Adam Stockman
- Department of Ophthalmology and Visual Sciences, the University of Iowa Carver College of Medicine, Iowa City, IA 52242, United States of America; Iowa Lions Eye Bank, Coralville, IA 52241, United States of America
| | - Edwin M Stone
- Department of Ophthalmology and Visual Sciences, the University of Iowa Carver College of Medicine, Iowa City, IA 52242, United States of America; Institute for Vision Research, the University of Iowa, Iowa City, IA 52242, United States of America
| | - Budd A Tucker
- Department of Ophthalmology and Visual Sciences, the University of Iowa Carver College of Medicine, Iowa City, IA 52242, United States of America; Institute for Vision Research, the University of Iowa, Iowa City, IA 52242, United States of America
| | - Todd E Scheetz
- Department of Ophthalmology and Visual Sciences, the University of Iowa Carver College of Medicine, Iowa City, IA 52242, United States of America; Institute for Vision Research, the University of Iowa, Iowa City, IA 52242, United States of America
| | - Robert F Mullins
- Department of Ophthalmology and Visual Sciences, the University of Iowa Carver College of Medicine, Iowa City, IA 52242, United States of America; Institute for Vision Research, the University of Iowa, Iowa City, IA 52242, United States of America.
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Lapeere H, Baeck M, Stockman A, Sabato V, Grosber M, Moutschen M, Lambert J, Vandebuerie L, de Montjoye L, Rabijns H, Allewaert K, Schrijvers R. A retrospective analysis omalizumab treatment patterns in patients with chronic spontaneous urticaria: a real-world study in Belgium. J Eur Acad Dermatol Venereol 2019; 34:127-134. [PMID: 31099916 PMCID: PMC7003755 DOI: 10.1111/jdv.15684] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 04/23/2019] [Indexed: 01/17/2023]
Abstract
Background Chronic spontaneous urticaria (CSU) is characterized by the repeated occurrence of persistent hives and/or angioedema for ≥6 weeks, without specific external stimuli. H1‐antihistamines have long been the standard of care of CSU, but many patients remain uncontrolled even at 4× the approved dose. Add‐on therapy with omalizumab has proven effective in clinical trials, but little is known about omalizumab treatment in Belgium. Objective To collect real‐world clinical data on omalizumab treatment in adults with CSU in Belgium. Methods This was an observational, retrospective chart review of adults with CSU, who initiated omalizumab treatment between August 2014 and December 2016 (maximum 28 months follow‐up). Results In total, 235 patients were included (median time from symptom onset to diagnosis, 5.4 months; median time from diagnosis to commencing omalizumab, 6.7 months). Treatments used before/after commencing omalizumab did not always adhere to guidelines; many patients (26.4%/11.1%) received first‐generation H1‐antihistamines, while 20.4% used omalizumab monotherapy after initiating treatment. The mean interval between omalizumab administrations was 4.8 (SD 1.7) weeks; 67.8% of patients had ≥1 interval prolongation and/or shortening. Mean baseline 7‐day Urticaria Activity Score (UAS7) was 32.0 (SD 6.05); this improved to 12.6 (SD 11.2) after 1 month of omalizumab. About 67.2% of patients reached UAS7 ≤ 6 (well controlled) during the study. A total of 87 patients stopped omalizumab and never restarted before the end of the observation period; the most prevalent reason was remission of symptoms (49.4% of patients), followed by lack of effect (12.6%), lost to follow‐up (6.9%) and adverse events (3.4%). Headache was the most common adverse event (n = 8/82). No anaphylaxis was reported. Conclusions This study revealed that patients initiated on omalizumab in Belgium had severe CSU at baseline, and showed substantial improvements after 1 month of treatment. Greater adherence to the prescription of guideline‐recommended medications is needed for the treatment of CSU.
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Affiliation(s)
- H Lapeere
- Department of Dermatology, Ghent University Hospital, Gent, Belgium
| | - M Baeck
- Department of Dermatology, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | - A Stockman
- Department of Dermatology, AZ Delta Campus Rembert Torhout, Torhout, Belgium
| | - V Sabato
- Department of Immunology-Allergology-Rheumatology, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - M Grosber
- Department of Dermatology, Universitair Ziekenhuis Brussel, Brussels, Belgium.,Vrije Universiteit Brussel, Brussels, Belgium
| | - M Moutschen
- Service Infectious Diseases and General Internal Medicine, CHU Liège, Liège, Belgium
| | - J Lambert
- Department of Dermatology University Hospital Antwerp, University of Antwerp, Antwerp, Belgium
| | - L Vandebuerie
- Groepspraktijk Dermatologie Roeselare, Roeselare, Belgium
| | - L de Montjoye
- Department of Dermatology, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | - H Rabijns
- N.V. Novartis Pharma S.A., Vilvoorde, Belgium
| | - K Allewaert
- N.V. Novartis Pharma S.A., Vilvoorde, Belgium
| | - R Schrijvers
- Laboratory of Clinical Immunology, KU Leuven Department of Microbiology and Immunology, Leuven, Belgium
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Majander A, Robson AG, João C, Holder GE, Chinnery PF, Moore AT, Votruba M, Stockman A, Yu-Wai-Man P. The pattern of retinal ganglion cell dysfunction in Leber hereditary optic neuropathy. Mitochondrion 2017; 36:138-149. [PMID: 28729193 PMCID: PMC5644721 DOI: 10.1016/j.mito.2017.07.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 07/02/2017] [Accepted: 07/14/2017] [Indexed: 02/07/2023]
Abstract
Leber inherited optic neuropathy (LHON) is characterized by subacute bilateral loss of central vision due to dysfunction and loss of retinal ganglion cells (RGCs). Comprehensive visual electrophysiological investigations (including pattern reversal visual evoked potentials, pattern electroretinography and the photopic negative response) performed on 13 patients with acute and chronic LHON indicate early impairment of RGC cell body function and severe axonal dysfunction. Temporal, spatial and chromatic psychophysical tests performed on 7 patients with acute LHON and 4 patients with chronic LHON suggest severe involvement or loss of the midget, parasol and bistratified RGCs associated with all three principal visual pathways.
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Affiliation(s)
- A Majander
- UCL Institute of Ophthalmology, London, UK; Moorfields Eye Hospital, London, UK; Department of Ophthalmology, University of Helsinki, Helsinki University Hospital, Helsinki, Finland.
| | - A G Robson
- UCL Institute of Ophthalmology, London, UK; Moorfields Eye Hospital, London, UK
| | - C João
- UCL Institute of Ophthalmology, London, UK
| | - G E Holder
- UCL Institute of Ophthalmology, London, UK; Moorfields Eye Hospital, London, UK
| | - P F Chinnery
- MRC-Mitochondrial Biology Unit, Cambridge Biomedical Campus, Cambridge, UK; Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - A T Moore
- UCL Institute of Ophthalmology, London, UK; Moorfields Eye Hospital, London, UK; Ophthalmology Department, UCSF School of Medicine, San Francisco, CA, United States
| | - M Votruba
- School of Optometry and Vision Sciences, Cardiff University, and Cardiff Eye Unit, University Hospital Wales, Cardiff, UK
| | - A Stockman
- UCL Institute of Ophthalmology, London, UK
| | - P Yu-Wai-Man
- UCL Institute of Ophthalmology, London, UK; Moorfields Eye Hospital, London, UK; Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK; Wellcome Trust Centre for Mitochondrial Research, Newcastle University, and Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK.
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Stockman A, Ripamonti C. Red-green flicker is encoded by a peak detector and limited by slew rate. J Vis 2014. [DOI: 10.1167/14.10.592] [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: 11/24/2022] Open
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Van Slycke S, Stockman A, Dionigi G, Carette R, Gillardin, JP, Brusselaers N, Vermeersch H. Harlequin syndrome after thyroidectomy for compressive retrosternal goiter. Case report and review of the literature. Acta Chir Belg 2014; 114:212-4. [PMID: 25102714 DOI: 10.1080/00015458.2014.11681012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A 74-year-old woman with known euthyroid multinodular retrosternal goiter necessitated an urgent intubation at home, due to acute respiratory distress evoked by tracheal compression. Extubation after a few days failed, and she underwent an urgent total thyroidectomy. During postoperative extubation the patient developed suddenly unilateral facial flushing and sweating at the left side, without ptosis of the left levator palpebrae superioris. These symptoms persisted during the next 24 hours. The skin at the right side of the face remained uninvolved. In the early postoperative period this appearance recurred at moments of emotions, exercise or heat. Beside this, the patient had a normal recovery. Six weeks later this reaction couldn't be provoked anymore. 'Harlequin' syndrome (unilateral facial flushing and sweating) is caused by a lesion of the controlateral sympathetic chain at the levels T2 and T3. It is unknown if the sweating and vasodilation at the "healthy" side is normal or if it is a reaction of hyperactivity.
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Affiliation(s)
- S. Van Slycke
- Department of General and Endocrine Surgery OLV Clinic Aalst Belgium
- Department of Head and Neck Surgery University Hospital Ghent Belgium
| | - A. Stockman
- Department of General and Endocrine Surgery OLV Clinic Aalst Belgium
| | - G. Dionigi
- Department of Endocrine Surgery-University of Insubria (Varese-Como) Italy
| | - R. Carette
- Department of Anesthesia and Intensive Care OLV Clinic Aalst Belgium
| | - J.-P. Gillardin,
- Department of General and Endocrine Surgery OLV Clinic Aalst Belgium
| | - N. Brusselaers
- Department of Internal Medicine and Infectious Diseases University Hospital Ghent Belgium
| | - H. Vermeersch
- Department of General and Endocrine Surgery OLV Clinic Aalst Belgium
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Stockman A. A psychophysical dissection and model of the common pathway that encodes colour and brightness. J Vis 2013. [DOI: 10.1167/13.15.30] [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: 11/24/2022] Open
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10
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Stockman A, Henning GB, Ripamonti C. Multiple S-cone signals inferred from flicker measurements suggest a network of indirect connections into luminance. J Vis 2013. [DOI: 10.1167/13.9.297] [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: 11/24/2022] Open
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Ripamonti C, Henning G, Stockman A. S-cone pathways. J Vis 2012. [DOI: 10.1167/12.9.109] [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: 11/24/2022] Open
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Petrova D, Henning B, Stockman A. The temporal characteristics of the early and late stages of the visual pathways signaling brightness and colour. J Vis 2010. [DOI: 10.1167/10.15.9] [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: 11/24/2022] Open
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13
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Smithson H, Stockman A. Using Stroop interference to reveal cognitive colour spaces. J Vis 2010. [DOI: 10.1167/10.15.7] [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: 11/24/2022] Open
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Stockman A, Ripamonti C, Henning GB, Robbie SJ, Moore AT, Bainbridge JW, Ali RR. Restoration of rod function following gene therapy in patients with mutations in the gene encoding the RPE65 protein required for recycling all-trans-retinal to 11-cis-retinal. J Vis 2010. [DOI: 10.1167/10.15.59] [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: 11/24/2022] Open
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15
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Ripamonti C, Crowther E, Stockman A. The S-cone luminance input depends on the level of M-cone adaptation. J Vis 2010. [DOI: 10.1167/8.6.956] [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: 11/24/2022] Open
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16
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Stockman A, Smithson HE. Transient tritanopia of a second kind redux: Delayed loss of S-cone sensitivity after long-wavelength field onset is consistent with the sluggish generation of an active photoproduct within the L- and M-cones. J Vis 2010. [DOI: 10.1167/6.13.5] [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: 11/24/2022] Open
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Stockman A, Jagle H, Pirzer M, Sharpe L. V *( ): a generalized luminous efficiency function for any condition of chromatic adaptation. J Vis 2010. [DOI: 10.1167/7.9.793] [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: 11/24/2022] Open
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18
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Stockman A, Smithson H, Aboshiha J, West P, Ripamonti C. Chromatic appearance depends on the rate of change of the colour signal (the "slew" rate). J Vis 2010. [DOI: 10.1167/8.6.1098] [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: 11/24/2022] Open
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Stockman A, Sharpe LT, Michaelides M, Moore AT, Webster AR, Smithson HE. Second sight: Vision sustained by a secondary activation of the phototransduction cascade. J Vis 2010. [DOI: 10.1167/6.6.120] [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: 11/24/2022] Open
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Ripamonti C, Woo WL, Crowther E, Stockman A. The S-cone contribution to luminance depends on the M- and L-cone adaptation levels: Silent surrounds? J Vis 2009; 9:10.1-16. [DOI: 10.1167/9.3.10] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Stockman A, Jagle H, Pirzer M, Sharpe LT. The dependence of luminous efficiency on chromatic adaptation. J Vis 2008; 8:1.1-26. [DOI: 10.1167/8.16.1] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Accepted: 08/21/2008] [Indexed: 11/24/2022] Open
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22
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Stockman A. S-cone signals in human postreceptoral pathways. J Vis 2005. [DOI: 10.1167/5.12.19] [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: 11/24/2022] Open
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Stockman A, Tait BD, Wolfe R, Brand CA, Rowley MJ, Varney MD, Buchbinder R, Muirden KD. Clinical, laboratory and genetic markers associated with erosions and remission in patients with early inflammatory arthritis: a prospective cohort study. Rheumatol Int 2005; 26:500-9. [PMID: 16151812 DOI: 10.1007/s00296-005-0027-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2004] [Accepted: 07/03/2005] [Indexed: 11/24/2022]
Abstract
We investigated the relationship between clinical, laboratory and genetic markers and outcome measures in 159 patients with recent onset of inflammatory arthritis (IA). The majority of patients were managed in community-based rheumatology practice. Median duration of arthritis at baseline was 3 months with median follow-up of 4.0 years (range 0-10). Markers of disease activity and 1987 ACR criteria for rheumatoid arthritis (RA) were estimated every 6 months for the first 2 years and annually thereafter. Presence of shared epitopes (SE) was established by PCR-based method. Main outcome variables were attainment of remission and presence of erosions on X-rays of hands and feet at 3 years. Remission was seen in 34.3% of patients and was independently related to age 60 and older (odds ratio (OR) 3.2; 95% confidence interval (CI), 1.2-8.7) and inversely to the presence of rheumatoid factor (RF) (OR 8.3; 95% CI, 3.2-21.3 for persistent arthritis). Patients with two SE were likely to have persistent arthritis (P=0.006), but this was not significant when corrected for RF. Independent predictors for erosions at 3 years were RF (OR 7.5; 95% CI, 1.9-29.5) and area under the curve for number of swollen joints (OR 1.08; 95% CI, 1.02-1.16). SE status was not predictive of erosions at 3 years (OR 1.6; 95% CI, 0.7-3.7). In univariate analysis, patients possessing DERAA motif on DRB1 were less likely to have erosive disease than without this motif at 4 years (OR 0.21; 95% CI, 0.0-0.9, P=0.037) but this finding was partly explained by adjusting for RF (adjusted OR 0.24; 95% CI 0.04-1.37). In this study of recent onset IA, active disease and RF were associated with poor outcome. Whilst SE did not predict erosive disease, patients with DERAA motif may be protected against erosions whilst the presence of two SE alleles suggests persistence of arthritis.
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Affiliation(s)
- A Stockman
- Rheumatology Unit, Royal Melbourne Hospital, Grattan Street, Parkville, 3050, Victoria, Australia.
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24
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Smithson H, Bourke A, Zaidi Q, Mollon J, Stockman A. Three ways to find a tritan line. J Vis 2004. [DOI: 10.1167/4.11.83] [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: 11/24/2022] Open
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25
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Stockman A, Williams M, Smithson H. Flicker-clicker: cross modality matching experiments. J Vis 2004. [DOI: 10.1167/4.11.86] [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: 11/24/2022] Open
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26
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Stockman A, Beele H, Vanderhaeghen Y, Naeyaert JM. Topical class I corticosteroids in 10 patients with bullous pemphigoid: correlation of the outcome with the severity degree of the disease and review of the literature. J Eur Acad Dermatol Venereol 2004; 18:164-8. [PMID: 15009295 DOI: 10.1111/j.1468-3083.2004.00870.x] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Treatment of bullous pemphigoid (BP) with systemic immunosuppressive agents, in particular with systemic corticosteroids, has many long-term side-effects. A dozen reports were published regarding the efficacy of topical corticosteroids in the treatment of bullous pemphigoid. OBJECTIVE To evaluate the efficacy of potent class I topical corticosteroids in relation to the affected body surface area (BSA) in patients with bullous pemphigoid and to review the literature. METHODS An open prospective trial with 10 patients with BP with measurement of the affected BSA. Treatment protocol consisted of three steps: potent class I topical corticosteroid treatment, systemic tetracyclines and systemic corticosteroids. Follow-up period was between 24 and 72 months. RESULTS Our study suggests a correlation between the success rate of topical corticosteroid treatment and the body surface area initially affected: all patients with an affected BSA of less than 20% healed with topical treatment only. The patients with more than 40% affected BSA needed systemic treatment with steroids. CONCLUSION Topical class I corticosteroids seem to be effective in healing lesions of BP, especially if less than 20% of the BSA is affected. This study comprises only 10 patients, making further studies necessary to draw definite conclusions.
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Affiliation(s)
- A Stockman
- Department of Dermatology, University of Ghent, Belgium
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Al-Hussaini M, Stockman A, Foster H, McCluggage WG. WT-1 assists in distinguishing ovarian from uterine serous carcinoma and in distinguishing between serous and endometrioid ovarian carcinoma. Histopathology 2004; 44:109-15. [PMID: 14764054 DOI: 10.1111/j.1365-2559.2004.01787.x] [Citation(s) in RCA: 195] [Impact Index Per Article: 9.8] [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: 11/28/2022]
Abstract
AIMS It has been suggested that WT-1 is helpful in distinguishing a primary ovarian serous carcinoma (OSC) from a primary uterine serous carcinoma (USC). Since both neoplasms are often disseminated at diagnosis and since USC often spreads to the ovary and vice versa, it may be difficult to ascertain the primary site. This is important, since adjuvant therapies for OSC and USC may differ. WT-1 staining patterns also differ between OSC and ovarian endometrioid carcinoma and so it is possible that WT-1 may assist in the distinction of these two neoplasms, which is sometimes problematic, especially with poorly differentiated tumours. This study aims to document the value of WT-1 in these settings. Cases of ovarian borderline serous tumour, primary peritoneal serous carcinoma (PPSC) and uterine endometrioid carcinoma were also studied. METHODS AND RESULTS Cases of OSC (n = 38), USC (n = 25) (in five of these cases there was also a component of endometrioid adenocarcinoma), ovarian endometrioid carcinoma (n = 13), uterine endometrioid carcinoma (n = 7), ovarian borderline serous tumour (n = 16) and PPSC (n = 6) were stained with WT-1. Cases were scored on a scale of 0-3, depending on the percentage of positive cells. The intensity of staining was scored as weak, moderate or strong. There was positive nuclear staining of 36 of 38 (94.7%) OSC with WT-1. In most OSC (68.4%), >50% of cells stained positively and staining was usually strong. Five of 25 (20%) USC were positive with only two cases exhibiting staining of >50% of cells. All primary ovarian and uterine endometrioid carcinomas were negative. All PPSC were positive, usually with diffuse strong immunoreactivity. Fourteen of 16 borderline serous tumours exhibited positivity with WT-1. CONCLUSIONS WT-1 is useful in distinguishing OSC (characteristically diffuse strong nuclear positivity) from USC (characteristically negative). However, rarely OSC is negative and occasional cases of USC are positive. WT-1 may also be helpful in differentiating poorly differentiated OSC from poorly differentiated ovarian endometrioid carcinoma.
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Affiliation(s)
- M Al-Hussaini
- Department of Pathology, Royal Group of Hospitals Trust, Belfast, UK
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Hoving JL, Buchbinder R, Green S, Forbes A, Bellamy N, Brand C, Buchanan R, Hall S, Patrick M, Ryan P, Stockman A. How reliably do rheumatologists measure shoulder movement? Ann Rheum Dis 2002; 61:612-6. [PMID: 12079902 PMCID: PMC1754152 DOI: 10.1136/ard.61.7.612] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [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: 11/04/2022]
Abstract
OBJECTIVE To assess the intrarater and interrater reliability among rheumatologists of a standardised protocol for measurement of shoulder movements using a gravity inclinometer. METHODS After instruction, six rheumatologists independently assessed eight movements of the shoulder, including total and glenohumeral flexion, total and glenohumeral abduction, external rotation in neutral and in abduction, internal rotation in abduction and hand behind back, in random order in six patients with shoulder pain and stiffness according to a 6x6 Latin square design using a standardised protocol. These assessments were then repeated. Analysis of variance was used to partition total variability into components of variance in order to calculate intraclass correlation coefficients (ICCs). RESULTS The intrarater and interrater reliability of different shoulder movements varied widely. The movement of hand behind back and total shoulder flexion yielded the highest ICC scores for both intrarater reliability (0.91 and 0.83, respectively) and interrater reliability (0.80 and 0.72, respectively). Low ICC scores were found for the movements of glenohumeral abduction, external rotation in abduction, and internal rotation in abduction (intrarater ICCs 0.35, 0.43, and 0.32, respectively), and external rotation in neutral, external rotation in abduction, and internal rotation in abduction (interrater ICCs 0.29, 0.11, and 0.06, respectively). CONCLUSIONS The measurement of shoulder movements using a standardised protocol by rheumatologists produced variable intrarater and interrater reliability. Reasonable reliability was obtained only for the movement of hand behind back and total shoulder flexion.
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Affiliation(s)
- J L Hoving
- Department of Clinical Epidemiology, Cabrini Hospital, Australia.
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29
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Abstract
The spectral sensitivities of middle- (M-) and long- (L-) wavelength-sensitive cones have been measured in dichromats of known genotype: M-cone sensitivities in nine protanopes, and L-cone sensitivities in 20 deuteranopes. We have used these dichromat cone spectral sensitivities, along with new luminous efficiency determinations, and existing spectral sensitivity and color matching data from normal trichromats, to derive estimates of the human M- and L-cone spectral sensitivities for 2 and 10 degrees dia. central targets, and an estimate of the photopic luminosity function [V(lambda)] for 2 degrees dia. targets, which we refer to as V(2)*(lambda). These new estimates are consistent with dichromatic and trichromatic spectral sensitivities and color matches.
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Affiliation(s)
- A Stockman
- Department of Psychology 0109, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, USA.
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Abstract
Tritanopic color matches (i.e. matches that depend on the middle- (M) and long- (L), but not short- (S) wavelength-sensitive cones) were made between two half-fields: one illuminated by either a 405 or a 436 nm Hg spectral line; the other by a light of variable wavelength and radiance. Our purpose was to test between rival M- and L-cone spectral sensitivities, which should predict the tritanopic matches. The observers were tritanopes, in whom functioning S-cones are lacking, or normal trichromats, in whom artificial tritanopia was induced by a strong, violet adapting field. The wavelengths found to match the 405 and 436 nm lights agreed poorly with those predicted by the cone spectral sensitivities of Smith and Pokorny (1975) [Vision Research, 15, 161], while the 405 nm matching wavelength agreed poorly with that predicted by Stockman, MacLeod and Johnson (1993) [Journal of the Optical Society of America, A10, 2491]. Both matching wavelengths agreed well, however, with the predictions of the Stockman and Sharpe (2000) [Vision Research] M- and L-cone spectral sensitivities, which lie within the range of measured matches.
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Affiliation(s)
- A Stockman
- Department of Psychology 0109, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0109, USA.
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Affiliation(s)
- A Stockman
- Department of Psychology, University of California, San Diego, La Jolla 92093-0109, USA
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Beele H, Verhaeghe E, Stockman A, Janssens A, Noens L, Geerts ML, Huys I, Naeyaert J. Pyoderma gangrenosum as an early revelator of acute leukemia. Dermatology 2000; 200:176-8. [PMID: 10773715 DOI: 10.1159/000018360] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [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: 11/19/2022] Open
Abstract
Bullous pyoderma gangrenosum is an atypical, more superficial variety of the classical pyoderma and is often associated with myeloproliferative disorders. We present the case of a patient who presented initially with subcutaneous nodules and who developed bullous lesions afterwards. Histological evaluation showed the presence of neutrophilic infiltrates in both lesions. A few months after the diagnosis of bullous pyoderma gangrenosum, an underlying leukemia was revealed. Our case illustrates the importance of regular blood and bone marrow examinations in patients with atypical bullous pyoderma gangrenosum, resulting in a rapid diagnosis of the underlying disease.
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Affiliation(s)
- H Beele
- Department of Dermatology, University Hospital Gent, Belgium
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Cook AD, Stockman A, Brand CA, Tait BD, Mackay IR, Muirden KD, Bernard CC, Rowley MJ. Antibodies to type II collagen and HLA disease susceptibility markers in rheumatoid arthritis. Arthritis Rheum 1999; 42:2569-76. [PMID: 10616002 DOI: 10.1002/1529-0131(199912)42:12<2569::aid-anr9>3.0.co;2-3] [Citation(s) in RCA: 36] [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] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To seek associations between antibodies to native and denatured type II collagen (NCII and DCII) and HLA in rheumatoid arthritis (RA). METHODS One hundred fourteen patients with clinically well-defined RA were HLA-DR and DQ typed. Those who were DR4 positive were subtyped for DRB1*0401-*0408 alleles by polymerase chain reaction using allele-specific oligonucleotide probes. Antibodies to human NCII and DCII (heat-denatured) were measured by enzyme-linked immunosorbent assay. The frequency of HLA alleles was compared in patients grouped according to the presence and absence of antibodies to NCII and DCII. RESULTS Twenty-seven patients (24%) were positive for antibodies to NCII. There was a significant increase in the frequency of HLA-DR7 in anti-NCII-positive patients compared with anti-NCII-negative patients (30% versus 9%; P = 0.019) and a significant decrease in HLA-DR3 (7% versus 28%; P = 0.044). Repeating the analyses after excluding the 16 patients who were DR7 positive revealed a significant increase in the frequency of HLA-DR1 in anti-NCII-positive patients compared with anti-NCII-negative patients (63% versus 27%; P = 0.045). Moreover, antibodies to NCII were associated with the third hypervariability region susceptibility sequence QRRAA that is present in DRB1*0101, *0404, *0405, and *0408 (84% versus 47%; P = 0.0085); 24 of 27 anti-NCII-positive patients were positive for either DR7, DR1, or DRB1*0404 or *0408. Thirty patients (26%) were positive for antibodies to DCII. There was a significant increase in the frequency of HLA-DR3 in anti-DCII-positive patients compared with anti-DCII-negative patients (40% versus 18%; P = 0.028). CONCLUSION The genetic associations between HLA-DR alleles and antibodies to CII in RA patients is in keeping with the collagen-induced arthritis model and implicates autoimmunity to CII as a major component in the multifactorial pathogenesis of RA.
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Affiliation(s)
- A D Cook
- Monash University, Clayton, Victoria, Australia
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Abstract
Anatomical and physiological studies of the mammalian retina have revealed two primary pathways available for the transmission of rod signals to the ganglion cells: one via ON rod bipolars, amacrine II cells, and ON and OFF cone bipolars, which is exquisitely designed for the transmission of single-photon absorption events; and a second via rod-cone gap junctions, and ON and OFF cone bipolars, which is designed for the transmission of multiple photon-absorption events at higher light levels. Psychophysical and electroretinographic (ERG) studies in normal observers and in two rare types of observer, who are devoid of either rod or cone function, support an analogous duality in the human visual system, the clearest signature of which is a loss of flicker visibility and ERG amplitude at frequencies near 15 Hz that results from destructive interference between sensitive 'slow' and insensitive 'fast' rod signals. The slow rod signal is most probably derived from the ON rod bipolar pathway and the fast signal from the rod-cone gap junction and cone pathways. Evidence has emerged recently for a third, insensitive rod pathway between rods and OFF cone bipolars, but it has so far only been observed clearly in rodents.
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Affiliation(s)
- L T Sharpe
- Forschungsstelle für Experimentelle Ophthalmologie, D-72076 Tübingen, Germany
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Sharpe LT, Stockman A, Jägle H, Knau H, Nathans J. L, M and L-M hybrid cone photopigments in man: deriving lambda max from flicker photometric spectral sensitivities. Vision Res 1999; 39:3513-25. [PMID: 10746123 DOI: 10.1016/s0042-6989(99)00061-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [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: 10/18/2022]
Abstract
Using heterochromatic flicker photometry, we have measured the corneal spectral sensitivities of the X-chromosome-linked photopigments in 40 dichromats, 37 of whom have a single opsin gene in their tandem array. The photopigments encoded by their genes include: the alanine variant of the normal middle-wavelength sensitive photopigment, M(A180); the alanine and serine variants of the normal long-wavelength sensitive photopigment, L(A180) and L(S180); four different L-M hybrid or anomalous photopigments, L2M3(A180), L3M4(S180), L4M5(A180) and L4M5(S180); and two variants of the L-cone photopigment, encoded by genes with embedded M-cone exon two sequences, L(M2; A180) and L(M2; S180). The peak absorbances (lambda max) of the underlying photopigment spectra associated with each genotype were estimated by correcting the corneal spectral sensitivities back to the retinal level, after removing the effects of the macular and lens pigments and fitting a template of fixed shape to the dilute photopigment spectrum. Details of the genotype-phenotype correlations are summarized elsewhere (Sharpe, L. T., Stockman, A., Jägle, H., Knau, H., Klausen, G., Reitner, A. et al. (1998). J. Neuroscience, 18, 10053-10069). Here, we present the individual corneal spectral sensitivities for the first time as well as details and a comparison of three analyses used to estimate the lambda max values, including one in which the lens and macular pigment densities of each observer were individually measured.
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Affiliation(s)
- L T Sharpe
- Forschungsstelle für Experimentelle Ophthalmologie, Tübingen, Germany.
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Abstract
We used two methods to estimate short-wave (S) cone spectral sensitivity. Firstly, we measured S-cone thresholds centrally and peripherally in five trichromats, and in three blue-cone monochromats, who lack functioning middle-wave (M) and long-wave (L) cones. Secondly, we analyzed standard color-matching data. Both methods yielded equivalent results, on the basis of which we propose new S-cone spectral sensitivity functions. At short and middle-wavelengths, our measurements are consistent with the color matching data of Stiles and Burch (1955, Optica Acta, 2, 168-181; 1959, Optica Acta, 6, 1-26), and other psychophysically measured functions, such as pi 3 (Stiles, 1953, Coloquio sobre problemas opticos de la vision, 1, 65-103). At longer wavelengths, S-cone sensitivity has previously been over-estimated.
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Affiliation(s)
- A Stockman
- Department of Psychology, University of California San Diego, La Jolla 92093-0109, USA.
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Sharpe LT, Stockman A, Jägle H, Knau H, Klausen G, Reitner A, Nathans J. Red, green, and red-green hybrid pigments in the human retina: correlations between deduced protein sequences and psychophysically measured spectral sensitivities. J Neurosci 1998; 18:10053-69. [PMID: 9822760 PMCID: PMC6793300] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
To analyze the human red, green, and red-green hybrid cone pigments in vivo, we studied 41 male dichromats, each of whose X chromosome carries only a single visual pigment gene (single-gene dichromats). This simplified arrangement avoids the difficulties of complex opsin gene arrays and overlapping cone spectral sensitivities present in trichromats and of multiple genes encoding identical or nearly identical cone pigments in many dichromats. It thus allows for a straightforward correlation between each observer's spectral sensitivity measured at the cornea and the amino acid sequence of his visual pigment. For each of the 41 single-gene dichromats we determined the amino acid sequences of the X-linked cone pigment as deduced from its gene sequence. To correlate these sequences with spectral sensitivities in vivo, we determined the Rayleigh matches to different red/green ratios for 29 single-gene dichromats and measured psychophysically the spectral sensitivity of the remaining green (middle wavelength) or red (long wavelength) cones in 37 single-gene dichromats. Cone spectral sensitivity maxima obtained from subjects with identical visual pigment amino acid sequences show up to a approximately 3 nm variation from subject to subject, presumably because of a combination of inexact (or no) corrections for variation in preretinal absorption, variation in photopigment optical density, optical effects within the photoreceptor, and measurement error. This variation implies that spectral sensitivities must be averaged over multiple subjects with the same genotype to obtain representative values for a given pigment. The principal results of this study are that (1) approximately 54% of the single-gene protanopes (and approximately 19% of all protanopes) possess any one of several 5'red-3'green hybrid genes that encode anomalous pigments and that would be predicted to produce protanomaly if present in anomalous trichromats; (2) the alanine/serine polymorphism at position 180 in the red pigment gene produces a spectral shift of approximately 2.7 nm; (3) for each exon the set of amino acids normally associated with the red pigment produces spectral shifts to longer wavelengths, and the set of amino acids normally associated with the green pigment produces spectral shifts to shorter wavelengths; and (4) changes in exons 2, 3, 4, and 5 from green to red are associated with average spectral shifts to long wavelengths of approximately 1 nm (range, -0.5 to 2.5 nm), approximately 3.3 nm (range, -0.5 to 7 nm), approximately 2.8 nm (range, -0.5 to 6 nm), and approximately 24.9 nm (range, 22.2-27.6 nm).
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Affiliation(s)
- L T Sharpe
- Forschungsstelle für Experimentelle Opthalmologie, Universit ats-Augenklinik Abteilung II, D-72076 Tübingen, Germany
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Stockman A, Plummer DJ. Color from invisible flicker: a failure of the Talbot-Plateau law caused by an early 'hard' saturating nonlinearity used to partition the human short-wave cone pathway. Vision Res 1998; 38:3703-28. [PMID: 9893801 DOI: 10.1016/s0042-6989(98)00049-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [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: 11/26/2022]
Abstract
The Talbot-Plateau law fails for flicker detected by the short-wavelength-sensitive (S) cones: a 30-40 Hz target, flickering too fast for the flicker to be resolved, looks more yellow than a steady target of the same average intensity. The color change, which is produced by distortion at an early compressive nonlinearity, was used to reveal a slightly bandpass S-cone temporal response before the distortion site and a lowpass response after it. The nonlinearity is probably a 'hard' nonlinearity that arises because the S-cone signal is limited by a response ceiling, which the mean signal level approaches and exceeds as the S-cone adaptation level increases. The nonlinearity precedes the combination of flicker signals from all three cone types.
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Affiliation(s)
- A Stockman
- Department of Psychology, University of California San Diego, La Jolla 92093-0109, USA.
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Abstract
Estimates of the density spectrum of the macular pigment (Wyszecki G, Stiles WS. Color Science: Concepts and Methods. Quantitative Data and Formulas. 1st ed. New York: Wiley, 1967); (Vos JJ. Literature review of human macular absorption in the visible and its consequences for the cone receptor primaries. Institute for Perception. Soesterberg, The Netherlands, 1972) are partially based on the difference between central and peripheral spectral sensitivities, measured under conditions chosen to isolate a single cone class (Stiles WS. Madrid: Union Internationale de Physique Pure et Appliquée, 1953;1:65-103). Such derivations assume that the isolated spectral sensitivity is the same at both retinal locations, save for the intervening macular pigment. If this is true, then the type of cone class mediating detection should not influence the calculated difference spectrum. To test this assumption, we measured central and peripheral spectral sensitivities in a deuteranope, a protanope and a normal trichromat observer: (a) for short-wave sensitive (S-) cone detection; and (b) for long-wave sensitive (L-) cone detection (deuteranope), for middle-wave sensitive (M-) cone detection (protanope) or for both L- and M-cone detection (normal trichromat). The difference spectra determined for L- or M-cone detection deviate significantly from those measured for S-cone detection, at wavelengths below 450 nm. A theoretical analysis suggests that the discrepancies are owing, in part, to regional variation in the optical density of the cone pigments; and that such receptor variation cannot be ignored when deriving the standard density spectrum of the macular pigment.
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Affiliation(s)
- L T Sharpe
- Forschungsstelle für Experimentelle Ophthalmologie, Universitäts-Augenklinik, Tübingen, Germany
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40
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Abstract
The spectral sensitivities of the short (S-), middle (M-) and long (L-) wave-sensitive cones have been measured in normal trichromats and in dichromats and monochromats of known genotype. For the S-cone sensitivities, three blue-cone monochromats and five normals were used; for the M-cone sensitivities, nine protanopes (three with a single L1M2 gene, three with a single L2M3 gene, one with both an L1M2 and an M gene, and two with both an L2M3 and an M gene); and for the L-cone sensitivities, 22 deuteranopes (five with a single L(ala180) gene and 17 with a single L(ser180) gene). We compare existing cone spectral sensitivity estimates with these results and with tritanopic color matches. The new findings are more consistent with the cone fundamentals of Stockman et al. (JOSA 1993(A10), 2491) than with those of Smith and Pokorny (Vision Research 1975(15), 161). The discrepancies that we find, however, are sufficient to warrant the replacement of both sets.
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Affiliation(s)
- A Stockman
- Department of Psychology, University of California San Diego, La Jolla 92093-0109, USA.
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Rowley MJ, Stockman A, Brand CA, Tait BD, Rowley GL, Sherritt MA, Mackay IR, Muirden KD, Bernard CC. The effect of HLA-DRB1 disease susceptibility markers on the expression of RA. Scand J Rheumatol 1998; 26:448-55. [PMID: 9433406 DOI: 10.3109/03009749709065718] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The study was designed to examine the effect on clinical expression of rheumatoid arthritis (RA) of HLA alleles, particularly DR4 and DR1 that contain susceptibility sequences for RA in the third hypervariable region (HVR3) of HLA-DRB1. We studied 114 consecutive Australian patients with RA attending a hospital outpatient clinic. The effects on indices of disease severity and activity of HLA DR4 and DR1, the DRB1*04 subtypes, and the polymorphism in the RA susceptibility sequence (QRRAA or QKRAA) were examined. The patients were initially divided into 6 groups, DR4,4; DR4,1; DR1,1; DR4/X; DR1,X, and DRX/X, and then further subdivided according to the actual HVR3 susceptibility sequence. The high risk conferred by the HVR3 susceptibility sequence, present in 76%, was confirmed, but 24% of the patients with long-standing seropositive erosive RA lacked this sequence. Among these those with DR2 had early-onset severe disease, and those with DR3 had late-onset milder disease. Differences in expression correlated with polymorphisms in the susceptibility sequence, in that active RA was associated more with QRRAA than QKRAA. There was no correlation of any HLA allele with disease severity. Our finding that the presence of the HVR3 sequence confers susceptibility and also influences the clinical expression and tempo of progression of RA suggests a role in pathogenesis for antigen presentation, whether of an autoantigenic molecule or a persisting infection.
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Affiliation(s)
- M J Rowley
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
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Bellamy N, Buchbinder R, Hall S, Lowthian P, Patrick MR, Ryan PF, Stockman A, Grant G, Green S, Campbell J. Fibromyalgia antirheumatic drug trials: Effects of a standardized instructional videotape on the reliability of observer-dependent outcome measures. Inflammopharmacology 1997; 5:261-72. [PMID: 17638135 DOI: 10.1007/s10787-997-0004-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/1997] [Accepted: 08/18/1997] [Indexed: 10/23/2022]
Abstract
AIMS A study was designed to assess the effects of a standardized instructional videotape on reducing interobserver variability for several commonly used observer-dependent outcome measures. METHODS During a single day, six rheumatologists independently examined six patients with fibromyalgia (FM) in a predetermined order using a Latin square design, before and after viewing a standardized videotape which demonstrated methods for performing dolorimetry and for detecting skinfold tenderness and reactive hyperaemia. Reliability coefficients were calculated based on the variance components of the analysis of variance (ANOVA) table. RESULTS Prestandardization reliability coefficients were <0.80 for 8 measures. Following standardization all reliability coefficients approximated to or exceeded 0.80. CONCLUSIONS An important and beneficial effect of the standardization procedure was noted for several outcome variables. Such reductions in observer variability have the potential to diminish sample size requirements for FM antirheumatic drug studies. The use of a videotape to achieve this goal has obvious cost and convenience advantages over one-on-one training procedures.
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Affiliation(s)
- N Bellamy
- University of Western Ontario, London, Canada
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Bellamy N, Muirden KD, Boyden K, McColl G, Moran H, Stockman A, Tellus MM, Wicks I, Campbell J. Ankylosing spondylitis antirheumatic drug trials: Effects of a standardized instructional viddeotape on the reliability of observer-dependent outcome measures. Inflammopharmacology 1997; 5:297-308. [PMID: 17638138 DOI: 10.1007/s10787-997-0007-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/1997] [Accepted: 08/18/1997] [Indexed: 11/30/2022]
Abstract
AIMS A study was designed to assess the effects of a standardized instruction videotape on reducing interobserver variability for several commonly used observer-dependent outcome measures. METHODS During a single day, six rheumatologists independently examined six patients with ankylosing spondylitis (AS) in a predetermined order using a Latin square design, before and after viewing a standardized videotape demonstrating 14 examination techniques. Reliability coefficients were calculated based on the variance components of the analysis of variance (ANOVA) table. RESULTS Prestandardization reliability coefficients were <0.80 for three measures. Following standardization 12 reliability coefficients exceeded 0.80. For the majority of measures prestandardization reliability coefficients were high and no further improvement in reliability could be demonstrated. For one measure of cervical extension, but not another, an important and beneficial effect in reliability was noted. It was not possible to achieve adequate reliability in the performance of the chest excursion measurement. CONCLUSIONS It is usually assumed that serial measurement in clinical trials should be performed by the same assessor because of concern regarding interobserver variability. However, the high levels of prestandardization interobserver reliability observed in this study indicate that for these variables serial measurements in a clinical trial could be made by different assessors, assuming they were equally skilled. This observation has important implications for outcome measurement in AS clinical trials. Although high levels of prestandardization reliability precluded the demonstration of any significant effect, we speculate that the videotape might be effective in training less experienced assessors. Nevertheless, an alternative approach to standardization may be required for the chest excursion measurement. Reductions in observer variability have the potential to diminish sample size requirements for AS antirheumatic drug studies. The use of a videotape to achieve this goal offers cost and convenience advantages over one-on-one training procedures, and this method should be further assessed in a group of less experienced assessors.
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Affiliation(s)
- N Bellamy
- University of Western Ontario, London
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Bellamy N, Muirden KD, Bendrups A, Boyden K, McColl G, Moran H, Stockman A, Tellus MM, Travers R, Campbell J. Rheumatoid arthritis antirheumatic drug trials: Effects of a standardized instructional videotape on the reliability of observer-dependent outcome measures. Inflammopharmacology 1997; 5:273-84. [PMID: 17638136 DOI: 10.1007/s10787-997-0005-x] [Citation(s) in RCA: 7] [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] [Received: 08/11/1997] [Accepted: 08/18/1997] [Indexed: 11/28/2022]
Abstract
AIMS A study was designed to assess the effects of a standardized instructional videotape on reducing interobserver variability for several commonly used observer-dependent outcome measures. METHODS During a single day, six rheumatologists independently examined six patients with rheumatoid arthritis (RA) in a predetermined order using a Latin square design, before and after viewing a standardized videotape demonstrating 13 examination techniques. Reliability coefficients were calculated based on the variance components of the analysis of variance (ANOVA) table. RESULTS Prestandardization reliability coefficients were >0.80 for all measures and remained above 0.80 following standardization. CONCLUSIONS It is usually assumed that serial measurement in clinical trials should be performed by the same assessor because of concern regarding interobserver variability. However, the high levels of prestandardization interobserver reliability observed in this study indicate that, for these variables, serial measurements in a clinical trial could be made by different assessors, assuming they were equally skilled. This observation has important implications for outcome measurement in RA clinical trials. Although high levels of prestandardization reliability precluded the demonstration of any significant effect, we speculate that the videotape might be effective in training less-experienced assessors. Reductions in observer variability have the potential to diminish sample size requirements for RA antirheumatic drug studies. The use of a videotape to achieve this goal offers cost and convenience advantages over one-on-one training procedures, and this method should be further assessed in less-experienced assessors.
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Affiliation(s)
- N Bellamy
- University of Western Ontario, London
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Abstract
The polygenic predisposition to RA is conferred particularly by disease susceptibility sequences in the HVR3 of HLA DRB1 present in those subtypes of DR4 and DR1 that are associated with RA. The aim of this study was to examine predisposing interactions between genes encoding HLA and immunoglobulin molecules. Accordingly, we compared the genetic background of 114 Australian patients with RA with that of Australian controls of similar ethnic background. We identified HLA-A, B, and DR phenotypes serologically, HLA-DR, DQ alleles, and subtypes of DR4 by DNA typing, and Gm allogenotypes and immunoglobulin switch region polymorphisms by RFLP. For the subjects with RA, we confirmed previously reported observations that included an excess of females, 71%, a high frequency of HLA types DR4 or DR1 of 77% versus controls 47%, and a high frequency of the HVR3 susceptibility sequences of 76%, with 24% homozygous, and 52% heterozygous for the sequences. We observed other genetic correlations in RA that included increases in frequencies of DR4 in males, DR1 in females, the class I specificity HLA-B27 overall but more particularly in females, 24% in females, versus 5% of controls, HLA-DQB1*0302 (DQ8) in DR4*0401-positive patients, and the Gm allogenotype 1,2,3;23 +/- ; 5,10, 15% of patients versus 4% of controls. Examination of switch region genes gave no evidence of differences in the polymorphisms distributions. Thus, the major genetic risks for RA that are conferred by female gender and the HVR3 of HLA DRB1 are modulated by interactions between gender and HLA class I and class II alleles, and the Gm allogenotype.
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Affiliation(s)
- M A Sherritt
- Neuroimmunology Laboratory, La Trobe University, Bundoora, Australia
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Abstract
In the human rod visual system, self-cancellation of flicker signals is observed at high rod intensity levels near 15 Hz, both perceptually and in the electroetinogram (ERG). This and other evidence suggests that two rod signals are transmitted through the human retina with different speeds of transmission. Here we report a series of flicker ERG recordings from a normal observer and an observer who lacks cone vision. From these results, we propose a quantitative model of the two rod signals, which assumes (1) that the amplitude of the slow signal grows linearly with log intensity but then saturates at approximately 1 scot. td; (2) that the amplitude of the fast signal grows linearly with intensity; (3) that there is a difference in time delay of approximately 33 ms between two rod signals of the same polarity (or of approximately 67 ms if the signals are of inverted polarity); and (4) that the time delay of both signals declines linearly with log intensity (by approximately 10 ms per log scot. td). These simple assumptions provide a remarkably good account of the experimental data. Our results and model are relevant to current anatomical theories of the mammalian rod visual system. We speculate that the slower signal in the human ERG may reflect the transmission of the rod response via the rod bipolars and the AII amacrine cells, while the faster signal may reflect its transmission via the rod-cone gap junctions and the cone bipolars. There are, however, several objections to this simple correspondence.
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Affiliation(s)
- A Stockman
- Department of Psychology, University of California San Diego, La Jolla 92093-0109, USA
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Cook AD, Rowley MJ, Stockman A, Muirden KD, Mackay IR. Specificity of antibodies to type II collagen in early rheumatoid arthritis. J Rheumatol Suppl 1994; 21:1186-91. [PMID: 7525955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
OBJECTIVE To analyze the antibody response to native type II collagen in early rheumatoid arthritis (RA), examining the immunoglobulin isotypes, and polypeptide epitopes recognized, in patients followed over a 2-year period from within 6 months of the first occurrence of symptoms. METHODS Sera from 16 patients were studied, of whom 10 had antibodies to native type II collagen and 6 did not. The clinical and laboratory assessment, carried out initially and at 6 monthly intervals included the number of 1958 ARA criteria fulfilled, Ritchie index, erythrocyte sedimentation rate, rheumatoid factor and radiological assessment. An ELISA was used to measure IgG, IgA and IgM antibodies, and immunoblotting to identify the number and location of epitopes, using polypeptides prepared by cyanogen bromide digestion of human type II collagen. RESULTS Antibodies to type II collagen were present in all sequential serum samples for the 10 antibody positive patients. None of the 6 patients who initially lacked antibodies developed them. The antibodies were of IgG isotype in 9, of IgA isotype in 8, and of IgM isotype exclusively in one. At the initial clinical assessment patients with antibodies to collagen were indistinguishable from those without. At 12 and 24 months patients with antibodies fulfilled significantly more ARA criteria than antibody negative patients. The patterns of antibody reactivity to collagen polypeptides by immunoblotting were constant over time but differed from patient to patient. CONCLUSION The presence of an established and persisting IgG antibody response to type II collagen in early RA before cartilage destruction is evident points to a subset of RA, perhaps equivalent to the collagen induced model in animals, in which this immune response is intrinsic to pathogenesis.
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Affiliation(s)
- A D Cook
- Centre for Molecular Biology and Medicine, Monash University, Clayton, Victoria, Australia
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Abstract
1. Flicker signals originating from the human rod photoreceptors seem to have access to two retinal pathways: one slow and sensitive, the other fast and insensitive. The phase lag between signals in the two pathways grows monotonically with frequency, reaching 180 deg near 15 Hz. 2. At 15 Hz, destructive interference between the slow and the fast signals can cause two related phenomena: (i) a suprathreshold intensity region--the perceptual null--within which the perception of flicker vanishes, and (ii) a double branching of the 15 Hz rod-detected flicker threshold versus intensity (TVI) curve. 3. Here we investigate the effect of changing target size on these phenomena in normal human observers. We find that the double-branched flicker TVI curve and the perceptual null are found for all targets larger than 2 deg in diameter. For smaller diameter targets, however, neither the lower branch of the double-branched flicker TVI curve nor the null are found. 4. While this might suggest that the slow rod signals are selectively disadvantaged by the use of small targets, phase measurements relative to a cone standard reveal that the slow signals are always present. For targets < or = 2 deg in diameter, however, they remain below detection threshold because of destructive interference with the fast rod signals. Thus, for small targets, the perceptual null is not absent, but has merged with (and therefore obliterated) the lower branch of the double-branched flicker TVI function. 5. This situation could arise if decreasing the target size causes a parallel reduction in the sensitivities of both pathways, rather than a selective reduction in the sensitivity of either one. Our findings are therefore consistent with a model in which the large-scale spatial organization of the two rod pathways is roughly similar.
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Affiliation(s)
- L T Sharpe
- Neurologische Universitätsklinik, Freiburg, FRG
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Abstract
Transient chromatic adaptation produced by an abrupt change of background color permits an easier and closer approach to cone isolation than does steady-state adaptation. Using this technique, we measured middle-wave-sensitive (M)-cone spectral sensitivities in 11 normals and 2 protanopes and long-wavelength-sensitive (L-) cone spectral sensitivities in 12 normals and 4 deuteranopes. Although there is great individual variation in the adapting intensity required for effective isolation, there is little variation in the shape of the M- and L-cone spectral-sensitivity functions across subjects. At middle and long wavelengths, our mean spectral sensitivities agree extremely well with dichromatic spectral sensitivities and with the M- and L-cone fundamentals of Smith and Pokorny [Vision Res. 15, 161 (1975)] and of Vos and Walraven [Vision Res. 11, 799 (1971)], both of which are based on the CIE (Judd-revised) 2 degrees color-matching functions (CMF's). But the agreement with the M-cone fundamentals of Estévez [Ph.D. dissertation, Amsterdam University (1979)] and of Vos et al. [Vision Res. 30, 936 (1990)], which are based on the Stiles-Burch 2 degrees CMF's, is poor. Using our spectral-sensitivity data, tritanopic color-matching data, and Stile's pi 3, we derive new sets of cone fundamentals. The consistency of the proposed fundamentals based on either the Stiles-Burch 2 degrees CMF's or the CIE 10 degrees large-field CMF's with each other, with protanopic and deuteranopic spectral sensitivities, with tritanopic color-matching data, and with short-wavelength-sensitive (S-) cone spectral-sensitivity data suggests that they are to be preferred over fundamentals based on the CIE 2 degrees CMF's.
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Affiliation(s)
- A Stockman
- Department of Psychology, University of California, San Diego, La Jolla 92093-0109
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Abstract
Psychophysical and electroretinographic observations in normal and achromat observers suggest that rod flicker signals have access to at least two retinal pathways: one (pi 0), slow and sensitive, predominating at scotopic luminance levels; the other (pi'0), fast and insensitive, predominating at mesopic ones. We have measured steady-state flicker detection sensitivities on background fields ranging from 430 to 640 nm in normal observers. Our results suggest that cone signals can reduce the sensitivity of pi'0, but have comparatively little effect on pi 0. The pi'0 field sensitivities derived from these measurements have been fitted with linear combinations of the scotopic luminosity function, V' lambda, the M-cone spectral sensitivity function, M lambda, and the L-cone function, L lambda. These fits demonstrate a clear cone influence on pi'0, but they cannot tell us unequivocally whether the influence is from the M-cones, from the L-cones or from both. Accordingly, we made similar measurements in dichromats, who lack one of the two longer wavelength cone types. These measurements revealed an L-cone influence on pi'0 in the deuteranope and an M-cone influence in the protanope. This suggests that both cone types can affect the sensitivity of pi'0. The finding that the steady-state cone signals reduce the sensitivity of pi'0 but have little effect on pi 0 could suggest that pi'0 signals travel through a faster cone pathway (with its own gain control at which both rod and cone signals can reduce rod threshold), while pi 0 signals travel through a separate rod pathway. However, it could simply reflect the fact that pi'0 predominates at higher luminances than pi 0 where the cone excitation level is inevitably greater. To examine the influence of the cones on pi 0 more closely, we: (i) produced transient cone excitation by alternating rod-equated 480 and 679 nm fields; and (ii) extended our steady-state measurements to include deep-red backgrounds of 650 and 680 nm. Both experiments revealed a small, but measurable influence of the cones on pi 0.
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Affiliation(s)
- L T Sharpe
- Neurologische Universitätsklinik, Freiburg, Germany
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