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1.
Dig Dis Sci ; 68(3): 729-735, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-35732970

RESUMO

INTRODUCTION: The coronavirus disease 19 (COVID-19) pandemic has disrupted healthcare delivery including elective endoscopy. We aimed to determine the prevalence of endoscopy cancellations in the COVID-19 era and identify patient characteristics associated with cancellation due to the pandemic. METHODS: Medical charts were reviewed for adults who cancelled an outpatient endoscopic procedure from 5/2020 to 8/2020. The association of patient characteristics with cancellation of endoscopy due to COVID-19 was assessed using logistic regression. RESULTS: There were 652 endoscopy cancelations with 211 (32%) due to COVID-19, 384 (59%) due to non-COVID reasons, and 57 (9%) undetermined. Among COVID-19 related cancellations, 75 (36%) were COVID-19 testing logistics related, 121 (57%) were COVID-19 fear related, and 15 (7%) were other. On adjusted analysis, the odds of cancellation due to COVID-19 was significantly higher for black patients (OR 2.04, 95% CI 1.07-3.88, p = 0.03), while patients undergoing EGD (OR 0.56, 95% CI 0.31-0.99, p = 0.05) or advanced endoscopy (OR 0.18, 95% CI 0.07-0.49, p = 0.001) had lower odds of cancellation. The odds of cancelling due to COVID-19 testing logistics was significantly higher among black patients (OR 3.12, 95% CI 1.03-9.46, p = 0.05) and patients with Medi-Cal insurance (OR 2.89, 95% CI 1.21-6.89, p = 0.02). CONCLUSION: Black race is associated with an increased risk of COVID-19 related cancellation. Specifically, black patients and those with Medi-Cal are at increased risk of cancellation related to logistics of obtaining pre-endoscopy COVID-19 testing. Racial and socioeconomic disparities in access to endoscopy may be further amplified by the COVID-19 pandemic and warrant further study.


Assuntos
COVID-19 , Adulto , Humanos , COVID-19/epidemiologia , Pandemias/prevenção & controle , Teste para COVID-19 , Grupos Raciais , Endoscopia
2.
Australas Phys Eng Sci Med ; 40(3): 491-543, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28914430

RESUMO

In 2001 the ACPSEM published a position paper on quality assurance in screen film mammography which was subsequently adopted as a basis for the quality assurance programs of both the Royal Australian and New Zealand College of Radiologists (RANZCR) and of BreastScreen Australia. Since then the clinical implementation of digital mammography has been realised and it has become evident that existing screen-film protocols were not appropriate to assure the required image quality needed for reliable diagnosis or to address the new dose implications resulting from digital technology. In addition, the advantages and responsibilities inherent in teleradiology are most critical in mammography and also need to be addressed. The current document is the result of a review of current overseas practice and local experience in these areas. At this time the technology of digital imaging is undergoing significant development and there is still a lack of full international consensus about some of the detailed quality control (QC) tests that should be included in quality assurance (QA) programs. This document describes the current status in digital mammography QA and recommends test procedures that may be suitable in the Australasian environment. For completeness, this document also includes a review of the QA programs required for the various types of digital biopsy units used in mammography. In the future, international harmonisation of digital quality assurance in mammography and changes in the technology may require a review of this document. Version 2.0 represented the first of these updates and key changes related to image quality evaluation, ghost image evaluation and interpretation of signal to noise ratio measurements. In Version 3.0 some significant changes, made in light of further experience gained in testing digital mammography equipment were introduced. In Version 4.0, further changes have been made, most notably digital breast tomosynthesis (DBT) testing and QC have been addressed. Some additional testing for conventional projection imaging has been added in order that sites may have the capability to undertake dose surveys to confirm compliance with diagnostic reference levels (DRLs) that may be established at the National or State level. A key recommendation is that dosimetry calculations are now to be undertaken using the methodology of Dance et al. Some minor changes to existing facility QC tests have been made to ensure the suggested procedures align with those most recently adopted by the Royal Australian and New Zealand College of Radiologists and BreastScreen Australia. Future updates of this document may be provided as deemed necessary in electronic format on the ACPSEM's website ( https://www.acpsem.org.au/whatacpsemdoes/standards-position-papers and see also http://www.ranzcr.edu.au/quality-a-safety/radiology/practice-quality-activities/mqap ).


Assuntos
Mamografia/normas , Garantia da Qualidade dos Cuidados de Saúde , Biópsia , Humanos , Controle de Qualidade
3.
Digestion ; 94(4): 215-221, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27931019

RESUMO

BACKGROUND/AIMS: Abstract presentations at scientific meetings provide an opportunity to communicate the results of important research. Unfortunately, many abstracts are not published as full manuscripts. At the 73rd scientific meeting of the American College of Gastroenterology in 2008, we evaluated factors associated with the publication of abstracts as manuscripts up to 6.5 years after presentation. METHODS: All abstracts, excluding case reports, presented at the meeting were evaluated. We systematically searched for matching manuscripts indexed in PubMed or EMBASE up to May 2015. We used logistic regression models to determine factors associated with manuscript publication and calculated ORs and 95% CIs. RESULTS: Of the included 791 abstracts, 249 (31.5%) were published as manuscripts within 6.5 years. Oral presentation (OR 2.11; 95% CI 1.15-3.87), multicenter studies (OR 2.67; 95% CI 1.44-4.95), abstracts by University-based authors (OR 1.80; 95% CI 1.20-2.72), and funded research (OR 2.15; 95% CI 1.43-3.23) were more likely to be published. Winning an award at the meeting was not associated with manuscript publication (OR 1.09; 95% CI 0.57-2.06). CONCLUSIONS: There is an urgent need to enhance the methods of disseminating scientific knowledge through publication of abstracts presented at gastroenterology meetings as manuscripts. Mentors should endeavor to encourage their mentees to complete this final stage of their scholarly activities.


Assuntos
Indexação e Redação de Resumos/estatística & dados numéricos , Congressos como Assunto , Gastroenterologia , Pesquisa Biomédica , Humanos , Modelos Logísticos , Manuscritos Médicos como Assunto , Sociedades Médicas
4.
Australas Phys Eng Sci Med ; 38(4): 543-9, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26330215

RESUMO

Clinical dosimetry requires an understanding of radiation energy to accurately determine the delivered dose. For many situations this is known, however there are also many situations where the radiation energy is not well known, thus limiting dosimetric accuracy. This is the case in personnel dosimetry where thermo luminescent (TL) dosimetry is the method of choice. Traditionally beam energy characteristics in personnel dosimetry are determined through discrimination with the use of various filters fitted within a radiation monitor. The presence of scattered and characteristic radiation produced by these metallic filters, however, can compromise the results. In this study the TL response of five materials TLD100, TLD100H, TLD200, TLD400 and TLD500, was measured at various X-ray energies. The TL sensitivity ratio for various combinations of materials as a function of X-ray energy was calculated. The results indicate that in personal dosimetry a combination of three or more TL detector system has a better accuracy of estimation of effective radiation energy of an X-ray beam than some of the current method of employed for energy estimation and has the potential to improve the accuracy in dose determination in a variety of practical situations. The development of this method also has application in other fields including quality assurance of the orthovoltage therapy machines, dosimetry intercomparisons of kilovoltage X-ray beams, and measurement of the dose to critical organs outside a treatment field of a megavoltage therapy beam.


Assuntos
Dosimetria Termoluminescente/métodos , Humanos , Radiografia/normas
5.
Radiat Prot Dosimetry ; 153(2): 185-9, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23173220

RESUMO

The EC (European Council) Directive on radiation protection of patients requires that criteria for acceptability of equipment in diagnostic radiology, nuclear medicine and radiotherapy be established throughout the member states. This study reviews the background to this requirement and to its implementation in practice. It notes and considers parallel requirements in the EC medical devices directive and International Electrotechnical Commission standards that it is also important to consider and that both sets of requirements should ideally be harmonised due to the global nature of the equipment industry. The study further reviews the types of criteria that can be well applied for the above purposes, and defines qualitative criteria and suspension levels suitable for application. Both are defined and relationships with other acceptance processes are considered (including acceptance testing at the time of purchase, commissioning and the issue of second-hand equipment). Suspension levels are divided into four types, A, B, C and D, depending on the quality of evidence and consensus they are based on. Exceptional situations involving, for example, new or rapidly evolving technology are also considered. The publication and paper focuses on the role of the holder of the equipment and related staff, particularly the medical physics expert and the practitioner. Advice on how the criteria should be created and implemented is provided for these groups and how this might be coordinated with the supplier. Additional advice on the role of the regulator is provided.


Assuntos
Medicina Nuclear/normas , Radiologia/normas , Radioterapia/normas , Europa (Continente) , Humanos , Medicina Nuclear/métodos , Lesões por Radiação/prevenção & controle , Proteção Radiológica/métodos , Radiologia/métodos , Radioterapia/métodos
6.
Radiat Prot Dosimetry ; 153(2): 227-9, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23169815

RESUMO

The use of dual-energy X-ray absorptiometry (DXA) units primarily for the assessment of fracture risk and in the diagnosis of osteoporosis is ubiquitous in Europe and ever-expanding in its implementation worldwide. DXA is known for its reported low radiation dose and precision in the determination of bone mineral density. However, the use of simple suspension criteria, as proposed in the new EC report RP-162, will identify units that are unfit for useful and safe diagnosis. Such suspension levels, however, are not a substitute for regular maintenance, quality control testing and optimisation of clinical outcomes.


Assuntos
Absorciometria de Fóton/normas , Densidade Óssea , Fraturas Ósseas/diagnóstico por imagem , Osteoporose/diagnóstico por imagem , Absorciometria de Fóton/instrumentação , Absorciometria de Fóton/métodos , Calibragem , Europa (Continente) , Fraturas Ósseas/diagnóstico , Humanos , Osteoporose/diagnóstico , Imagens de Fantasmas , Controle de Qualidade , Proteção Radiológica/métodos , Radiometria/métodos , Risco , Resultado do Tratamento
7.
Rev. argent. mastología ; 30(106): 8-11, abr. 2011. ilus
Artigo em Espanhol | LILACS | ID: lil-605638

RESUMO

Se presenta um caso de carcinosarcoma mamário (CSM) diagnosticado en una mujer de 41 años de edad. Se describe la histopatología y se realiza una revisión de la bibliografía, resumiendo el manejo de estos casos.


Assuntos
Mama , Carcinossarcoma
8.
Radiat Prot Dosimetry ; 139(1-3): 418-21, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20159920

RESUMO

The International Atomic Energy Agency (IAEA) has a mandate to assist member states in areas of human health and particularly in the use of radiation for diagnosis and treatment. Clinical audit is seen as an essential tool to assist in assuring the quality of radiation medicine, particularly in the instance of multidisciplinary audit of diagnostic radiology. Consequently, an external clinical audit programme has been developed by the IAEA to examine the structure and processes existent at a clinical site, with the basic objectives of: (1) improvement in the quality of patient care; (2) promotion of the effective use of resources; (3) enhancement of the provision and organisation of clinical services; (4) further professional education and training. These objectives apply in four general areas of service delivery, namely quality management and infrastructure, patient procedures, technical procedures and education, training and research. In the IAEA approach, the audit process is initiated by a request from the centre seeking the audit. A three-member team, comprising a radiologist, medical physicist and radiographer, subsequently undertakes a 5-d audit visit to the clinical site to perform the audit and write the formal audit report. Preparation for the audit visit is crucial and involves the local clinical centre completing a form, which provides the audit team with information on the clinical centre. While all main aspects of clinical structure and process are examined, particular attention is paid to radiation-related activities as described in the relevant documents such as the IAEA Basic Safety Standards, the Code of Practice for Dosimetry in Diagnostic Radiology and related equipment and quality assurance documentation. It should be stressed, however, that the clinical audit does not have any regulatory function. The main purpose of the IAEA approach to clinical audit is one of promoting quality improvement and learning. This paper describes the background to the clinical audit programme and the IAEA clinical audit protocol.


Assuntos
Comissão Para Atividades Profissionais e Hospitalares/organização & administração , Diagnóstico por Imagem/normas , Agências Internacionais , Radiologia/normas
9.
Australas Phys Eng Sci Med ; 30(2): 65-100, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17682397

RESUMO

In 2001 the ACPSEM published a position paper on quality assurance in screen film mammography which was subsequently adopted as a basis for the quality assurance programs of both the Royal Australian and New Zealand College of Radiologists (RANZCR) and of BreastScreen Australia. Since then the clinical implementation of digital mammography has been realised and it has become evident that existing screen-film protocols were not appropriate to assure the required image quality needed for reliable diagnosis or to address the new dose implications resulting from digital technology. In addition, the advantages and responsibilities inherent in teleradiology are most critical in mammography and also need to be addressed. The current document is the result of a review of current overseas practice and local experience in these areas. At this time the technology of digital imaging is undergoing significant development and there is still a lack of full international consensus about some of the detailed Quality Control tests that should be included in quality assurance (QA) programs. This document describes the current status in digital mammography QA and recommends test procedures that may be suitable in the Australasian environment. For completeness, this document also includes a review of the QA programs required for the various types of digital biopsy units used in mammography. In the future, international harmonisation of digital quality assurance in mammography and changes in the technology may require a review of this document. Accordingly, updates of this document will be provided as deemed necessary in electronic format on the ACPSEM's website (see http://www.acpsem.org.au/au/subgroup/radiology/RadiologySG_index.html).


Assuntos
Mamografia/instrumentação , Mamografia/normas , Garantia da Qualidade dos Cuidados de Saúde , Austrália , Biópsia , Humanos , Nova Zelândia
10.
Australas Phys Eng Sci Med ; 28(3): 151-8, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16250468

RESUMO

The image quality and dose parameters from a 2004 Siemens Axiom Artis dBC cardiac biplane with flat panel detector were evaluated and compared to similar parameters evaluated for a 1977 Toshiba DPF 2000A biplane cardiac unit with a conventional image intensifier. Image quality assessment was performed with the Westmead test object; using solid water as a patient equivalent absorber. The patient dose comparison of the two systems is based on dose area product meter readings for 1512 patient cases recorded over 6 months following installation of the Siemens flat panel digital unit. The image quality results indicate that: (a) high contrast resolution was better with the digital flat panel unit, (b) low contrast resolution is similar between systems, and (c) the threshold contrast of the flat panel system is the same or inferior to that of the image intensifier system. Input dose to the surface of the flat panel detector showed a strong dependence on field size, similar to the behaviour of image intensifier system. For the most common clinical procedure--Left Heart Study via Judkins--the average total dose area product reading was 64.0 Gy-cm2 against 67.7 Gy-cm2 for the digital and conventional units respectively (p = 0.27) indicating no significant difference in dose performance between the two x-ray machines.


Assuntos
Fluoroscopia/instrumentação , Coração/diagnóstico por imagem , Intensificação de Imagem Radiográfica/instrumentação , Interpretação de Imagem Radiográfica Assistida por Computador/instrumentação , Ecrans Intensificadores para Raios X , Análise de Falha de Equipamento , Imagens de Fantasmas , Doses de Radiação , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
11.
Nature ; 423(6940): 621-3, 2003 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-12789332

RESUMO

Little is known about the origins of globular clusters, which contain hundreds of thousands of stars in a volume only a few light years across. Radiation pressure and winds from luminous young stars should disperse the star-forming gas and disrupt the formation of the cluster. Globular clusters in our Galaxy cannot provide answers; they are billions of years old. Here we report the measurement of infrared hydrogen recombination lines from a young, forming super star cluster in the dwarf galaxy NGC5253. The lines arise in gas heated by a cluster of about one million stars, including 4,000-6,000 massive, hot 'O' stars. It is so young that it is still enshrouded in gas and dust, hidden from optical view. The gases within the cluster seem bound by gravity, which may explain why the windy and luminous O stars have not yet blown away those gases. Young clusters in 'starbursting' galaxies in the local and distant Universe may also be gravitationally confined and cloaked from view.

12.
J Clin Forensic Med ; 10(4): 221-9, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15274997

RESUMO

INTRODUCTION: St. Mary's Centre conducts forensic examinations on behalf of Greater Manchester Police. The sexual assault rate (and reporting to police) across ethnic communities is of some debate. An audit was conducted to assess recording of clients' ethnicity, and representation of clients from local and ethnic communities of Greater Manchester County. METHODOLOGY: Performances of recording ethnicity, area of residence, and assault type relevant to all new clients in 2001 (n=653) were measured against standards. Figures relating to local and ethnic populations were also compared to 1991 Census data as a guide. RESULTS: Recording clients' ethnicity and assault type were below required standards, recording area of residence was above. Overall ethnic minority representation was above general population figures, but differences existed within communities. Manchester city resident clients were over-represented compared to other county boroughs. CONCLUSIONS: Factors affecting record-keeping included: client's awareness of the assault; if the client was a police referral; if an examination was conducted. The high number of black clients accounted for the 'over-representation' of ethnic minorities, masking under-representation of other ethnic communities. The 'over-representation' of Manchester city residents is considered to be a function of the Centre's Manchester location, and the city's greater opportunities for late-night socialising.

13.
J Anat ; 201(5): 424, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17103769
14.
Ophthalmology ; 108(12): 2232-6, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11733264

RESUMO

OBJECTIVE: A clinicopathologic study to evaluate the histopathologic features associated with Acanthamoeba keratitis and chorioretinitis. DESIGN: Retrospective observational case report. METHODS: On the basis of the clinical history and histologic appearance, the enucleated eye and native corneal button were examined using hematoxylin-eosin stains and special periodic acid-Schiff and Gomori methenamine silver stains. RESULTS: Results of histologic examination of the cornea and retina showed numerous Acanthamoeba cysts in the cornea stromal layers, the necrotic retina, and preretinal and subretinal spaces. CONCLUSIONS: To the authors' knowledge, this is the first proven histologic case of ipsilateral chorioretinitis secondary to primary chronic keratitis caused by Acanthamoeba. The patient had a 30-month history of recurrent keratitis requiring four penetrating keratoplasties. We believe the chorioretinitis resulted from direct spread of the corneal amebic infection. The spread of the Acanthamoeba may have been facilitated by a combined keratoplasty, extracapsular cataract extraction, and intraocular lens insertion. In both specimens, the native corneal button and the enucleated eye with a corneal transplant, the general pathologists overlooked the presence of Acanthamoeba.


Assuntos
Ceratite por Acanthamoeba/diagnóstico , Coriorretinite/diagnóstico , Córnea/patologia , Retina/patologia , Ceratite por Acanthamoeba/parasitologia , Ceratite por Acanthamoeba/cirurgia , Idoso , Coriorretinite/parasitologia , Coriorretinite/cirurgia , Córnea/parasitologia , Enucleação Ocular , Humanos , Ceratoplastia Penetrante , Masculino , Reoperação , Retina/parasitologia , Estudos Retrospectivos , Acuidade Visual , Vitrectomia
15.
J Glaucoma ; 10(5): 411-3, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11711840

RESUMO

PURPOSE: To report the histopathologic and immunohistochemical findings from the iridectomy specimen of a patient with acquired unilateral iris heterochromia due to latanoprost. PATIENT AND METHODS: A 45-year-old woman with open-angle glaucoma and unilateral iris heterochromia was evaluated for uncontrolled intraocular pressure increase. Subsequently, the patient underwent trabeculectomy with mitomycin C and an iridectomy specimen was obtained for analysis. RESULTS: The histopathologic analysis of the iridectomy specimen did not reveal any nuclear atypia, nuclear crowding, or mitotic figures. Immunohistochemical studies showed that the iris melanocytes were negative for HMB45 and S-100, and weakly positive for Melan A. CONCLUSION: Latanoprost-associated iris color change may exhibit a diffuse, uniform, dark velvet-brown appearance, thereby simulating diffuse iris melanoma. Histopathologic and immunohistochemical analysis confirmed the benign characteristics of the affected iris melanocytes.


Assuntos
Anti-Hipertensivos/efeitos adversos , Glaucoma de Ângulo Aberto/tratamento farmacológico , Doenças da Íris/induzido quimicamente , Iris/efeitos dos fármacos , Melanose/induzido quimicamente , Prostaglandinas F Sintéticas/efeitos adversos , Anti-Hipertensivos/uso terapêutico , Diagnóstico Diferencial , Feminino , Glaucoma de Ângulo Aberto/cirurgia , Humanos , Pressão Intraocular/efeitos dos fármacos , Iris/patologia , Iris/cirurgia , Doenças da Íris/diagnóstico , Doenças da Íris/cirurgia , Latanoprosta , Melanose/diagnóstico , Melanose/cirurgia , Pessoa de Meia-Idade , Mitomicina/uso terapêutico , Prostaglandinas F Sintéticas/uso terapêutico , Trabeculectomia
16.
Invest Ophthalmol Vis Sci ; 42(6): 1160-3, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11328722

RESUMO

PURPOSE: To summarize and compare the various histologic methodologies for using nucleoli to assess the malignant potential of uveal melanoma. METHODS: This was an observational series of 100 samples of uveal melanoma in which histologic sections were studied. The cases were selected so that approximately half (n = 49) of the tumors were from patients who had died of metastatic malignant melanoma. The 51 remaining tumors were from patients who had survived at least 9 years without development of metastasis. Central sections from the uveal melanomas were stained using the colloidal silver nitrate stain for nucleolar organizing regions (AgNOR). These were compared with an adjacent hematoxylin and eosin (H&E)-stained section. A light microscope with a micrometer inset into the eyepiece (x10) was used at a final magnification of x1000 under oil immersion to measure the length of the nucleolus along the longest axis and the width perpendicular to that axis. From at least twenty cells selected from random fields throughout the tumor, the mean of the 10 longest and widest nucleoli (MLN) was calculated. Seven samples had to be discarded because the nucleoli were unmeasurable. RESULTS: T-tests and Cox proportional hazard regression analysis indicated that the MLN of nucleolar length as measured on AgNOR-stained slides was as significant as cell type but was more significant than other histopathologic prognosticating variables measured and evaluated in this study. These prognosticators included tumor size, calculated as the largest tumor dimension; MLN width; and MLN length, as measured on H&E-stained sections. CONCLUSIONS: It has previously been demonstrated that AgNOR-stained nucleoli, unlike H&E-stained nucleoli, can be captured and measured by an automated image analyzer with prognostically significant results. This new method of simple oil-immersion measurements of the longest AgNOR-stained nucleoli length in microscopic sections of uveal melanoma provides an inexpensive and highly significant method for predicting outcome in patients with uveal melanoma. Because of the high contrast with the background, the silver-stained nucleoli clearly define the nucleolar boundaries, rendering them readily discernible and allowing greater ease and speed of measurement when compared with H&E-stained nucleoli. The method of random sampling that was used was comparable with linear sampling in predicting outcome. Highly necrotic tumors, however, had to be excluded from the study because of loss of nucleolar morphology.


Assuntos
Nucléolo Celular/patologia , Melanoma/patologia , Neoplasias Uveais/patologia , Humanos , Metástase Neoplásica , Região Organizadora do Nucléolo/patologia , Coloração pela Prata
17.
Science ; 292(5520): 1334-9, 2001 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-11359002

RESUMO

In the current paradigm, Oort cloud comets formed in the giant planets' region of the solar nebula, where temperatures and other conditions varied greatly. The measured compositions of four such comets (Halley, Hyakutake, Hale-Bopp, and Lee) are consistent with formation from interstellar ices in the cold nebular region beyond Uranus. The composition of comet C/1999 S4 (LINEAR) differs greatly, which suggests that its ices condensed from processed nebular gas, probably in the Jupiter-Saturn region. Its unusual organic composition may require reevaluation of the prebiotic organic material delivered to the young Earth by comets.

18.
J Refract Surg ; 17(2): 105-9, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11310758

RESUMO

PURPOSE: To determine if moderate numbers of low fluence, 193-nm excimer laser pulses modify or damage the corneal stroma. METHODS: The corneal epithelium of fresh bovine eyes was scraped off and the exposed stroma was irradiated with 200 low fluence laser pulses from an argon fluoride excimer laser. This process was performed on five eyes each at two laser fluences, 10 mJ/cm2 and 30 mJ/cm2. The ten irradiated and three control (unirradiated) corneas were sectioned and studied by electron microscopy. The maximum and minimum thickness of the anterior layer of randomly oriented collagen fibers was measured using electron microscopy. RESULTS: The mean maximum thickness of the anterior randomly oriented layer of collagen was 1.23 +/- 0.45 microm in the control corneas, 0.67 +/- 0.32 microm in the corneas irradiated at 10 mJ/cm2, and 0.10 +/- 0.12 microm in the corneas irradiated at 30 mJ/cm2. The mean thickness of corneal stroma removed was 0.7 microm at a fluence of 10 mJ/cm2 and 1.1 microm at a fluence of 30 mJ/cm2. A thin, electron-dense pseudomembrane was present at both fluences. CONCLUSION: We report removal of bovine corneal stroma at 10 mJ/cm2--below the previously reported ablation threshold of 20 mJ/cm2.


Assuntos
Substância Própria/cirurgia , Substância Própria/ultraestrutura , Ceratectomia Fotorrefrativa/métodos , Animais , Bovinos , Colágeno/ultraestrutura , Lasers de Excimer
19.
Am J Ophthalmol ; 131(2): 232-6, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11228300

RESUMO

PURPOSE: To report associations between prognosis, total tumor necrosis, scleritis, and episcleritis in choroidal and ciliary body melanomas. METHODS: In this retrospective observational histopathologic study, 157 totally necrotic melanomas and 177 melanomas that were not totally necrotic of choroidal and ciliary body were retrieved from the Registry of Ophthalmic Pathology. The eyes were examined for the histologic evidence of inflammatory cells within the sclera and episcleral tissues. Contingency table, Kaplan-Meier, and Cox proportional hazard regression analyses were performed. In the survival analyses, only deaths with metastatic melanoma were considered as events in the statistical analysis. RESULTS: Among the totally necrotic melanomas, 118 of 157 (75.1%) had both episcleritis and scleritis; two of 157 (1.3%) had scleritis only; 29 of 157 (18.5%) had episcleritis only; and eight of 157 (5.1%) had neither episcleritis nor scleritis. Among the non-necrotic melanomas, 23 of 177 (12.9%) had both episcleritis and scleritis; eight of 177 (4.5%) had scleritis only; 71 of 177 (40.1%) had episcleritis only; and 75 of 177 (42.3%) had neither episcleritis nor scleritis. Cox regression indicated that total necrosis and scleritis were prognostically significant (P <.05) when analyzed univariately but not significant when analyzed multivariately with tumor size. CONCLUSIONS: Scleritis and episcleritis were statistically significantly associated with total tumor necrosis. There was a higher incidence of episcleritis than scleritis in both the necrotic and non-necrotic tumor types. Associations with patient outcome were identified for necrosis and scleritis. However, these associations were statistically insignificant when the prognostic effect of tumor size was also considered in a multivariate model.


Assuntos
Neoplasias da Coroide/complicações , Corpo Ciliar/patologia , Melanoma/complicações , Esclerite/complicações , Neoplasias Uveais/complicações , Neoplasias da Coroide/diagnóstico , Neoplasias da Coroide/mortalidade , Humanos , Melanoma/diagnóstico , Melanoma/mortalidade , Necrose , Prognóstico , Estudos Retrospectivos , Esclerite/diagnóstico , Esclerite/mortalidade , Taxa de Sobrevida , Neoplasias Uveais/diagnóstico , Neoplasias Uveais/mortalidade
20.
Am J Ophthalmol ; 131(3): 400-1, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11239887

RESUMO

PURPOSE: To report a rare ectopic chordoma within the orbital wall. METHODS: Case report. RESULTS: A 63-year-old woman developed swelling of the eyelid, tearing, blurred vision, and progressive proptosis RE of 1 month's duration. Neuroimaging studies revealed an osteolytic mass with epicenter at the sphenozygomatic suture that eroded intracranially, invaded into the orbit, and compressed orbital soft tissues. Surgical debulking was done followed by radiation treatment. The pathologic findings of physaliphorous epithelial cells with multiple vacuoles containing mucin, prominent nuclei, and positive immunohistochemical staining for S-100, Vimentin, epithelial membrane antigen, and pancytokeratin were diagnostic for chordoma. CONCLUSION: Orbital wall ectopic localization of a chordoma distant from the clivus is a rare occurrence.


Assuntos
Cordoma/patologia , Neoplasias Orbitárias/patologia , Biomarcadores Tumorais/análise , Cordoma/química , Cordoma/terapia , Feminino , Humanos , Queratinas/análise , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Mucina-1/análise , Invasividade Neoplásica , Proteínas de Neoplasias/análise , Neoplasias Orbitárias/química , Neoplasias Orbitárias/terapia , Proteínas S100/análise , Tomografia Computadorizada por Raios X , Vimentina/análise
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