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1.
Curr Opin Ophthalmol ; 34(4): 275-279, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37070524

RESUMO

PURPOSE OF REVIEW: Although refractive surgery is one of the most commonly performed ophthalmic procedures, there is a relative paucity of literature on residency and fellowship refractive surgery education. The purpose of this article is to review the current state and recent updates to refractive surgery education and to evaluate the safety and visual outcomes of trainee performed refractive procedures. RECENT FINDINGS: Currently, there is no standard refractive surgery curriculum in the United States apart from required mandatory minimum refractive requirements for residents and fellows. Our survey of residency programs confirms that refractive training is extremely varied, ranging from a dedicated refractive rotation with direct surgical experience to only didactics or observation of procedures. There is a proposed standardized framework for refractive surgery training for the military, which may be a starting point in developing a more comprehensive refractive surgery curriculum in residency education. Multiple studies have reinforced the safety of resident and fellow performed refractive surgery. SUMMARY: Refractive surgery is an increasingly popular procedure and a more comprehensive refractive education is paramount. Future studies are needed to determine how best to provide the fundamental training and surgical experience for trainees in the fast-changing landscape of refractive surgery.


Assuntos
Internato e Residência , Oftalmologia , Procedimentos Cirúrgicos Refrativos , Humanos , Estados Unidos , Educação de Pós-Graduação em Medicina/métodos , Currículo , Bolsas de Estudo , Competência Clínica
2.
J Cataract Refract Surg ; 48(10): 1219, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-36179353

RESUMO

A 54-year-old man with noncontributory medical history presented to an ophthalmologist in January 2022 after 10 days of irritation in his right eye. The patient recounts having felt something get into his eye and under his contact lens (CL) while he was climbing into his car, but he was unsure what the foreign body may have been. Initial examination by the clinician found uncorrected distance visual acuity of 20/100-2 with a corneal abrasion, 4+ corneal edema, and 3+ conjunctival injection, for which he was placed on topical antibiotics (ocuflox and tobradex) with a bandage CL. 1 week later, visual acuity was 20/80, corneal edema had improved, and he was noted to have corneal scarring and an epithelial defect. Tobradex was continued while prednisolone drops and preservative-free artificial tears were started. 1 week later, the patient had worsening visual acuity to 20/250 and was referred to our tertiary center. On initial consultation, the patient had an uncorrected distance visual acuity of 20/500 and an uncorrected near visual acuity of >J10 in the right eye. Slitlamp examination of the right eye was significant for vortex keratopathy and mild corneal pannus with 360-degree subtle conjunctivalization of the limbus ( Figure 1JOURNAL/jcrs/04.03/02158034-202210000-00022/figure1/v/2022-10-03T121249Z/r/image-tiff ). The corneal topograph was obtained showing significant surface irregularity on the Placido image ( Figure 2JOURNAL/jcrs/04.03/02158034-202210000-00022/figure2/v/2022-10-03T121249Z/r/image-tiff ). Examination of the left eye was unremarkable. The ocular history is significant for myopia of -4.0 diopters and CL use for 20 years. The patient admits to regularly wearing soft CLs for several days straight and only removing them for a few hours. Antibiotics were discontinued, corticosteroid drops were reduced in frequency, and the patient was continued on preservative-free artificial tears. What imaging might you consider? What is your differential diagnosis at this point? What would be the most appropriate surgical and/or medical interventions? What would you counsel in prognosis for this patient?


Assuntos
Lentes de Contato Hidrofílicas , Distrofias Hereditárias da Córnea , Edema da Córnea , Lesões da Córnea , Antibacterianos/uso terapêutico , Distrofias Hereditárias da Córnea/tratamento farmacológico , Edema da Córnea/diagnóstico , Edema da Córnea/tratamento farmacológico , Edema da Córnea/etiologia , Humanos , Lubrificantes Oftálmicos , Masculino , Pessoa de Meia-Idade , Prednisolona , Combinação Tobramicina e Dexametasona , Transtornos da Visão
3.
BMC Ophthalmol ; 22(1): 15, 2022 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-34998368

RESUMO

BACKGROUND: The goal of this study was to investigate the incidence of departures from routine care at the postoperative week 1 (POW1) visit following uneventful resident-performed cataract surgery in asymptomatic patients who had a normal postoperative day 1 (POD1) examination. METHODS: A retrospective chart review of phacoemulsification surgeries performed by the senior resident class at Montefiore Medical Center between June 20, 2018 and April 1, 2019 was performed. The most recent preoperative visit note, operative report, POD1 visit note, and POW1 visit note were evaluated and variables were recorded. Exclusion criteria consisted of any complications that would have necessitated close follow-up and a POW1 visit, whether discovered preoperatively, intraoperatively, at the POD1 visit, or leading up to the POW1 visit. The primary outcome measure was the incidence of unanticipated management changes at the POW1 visit following resident-performed cataract surgery. RESULTS: The charts of 292 surgical cases of 234 patients that underwent phacoemulsification with intraocular lens implantation were reviewed. 226 cases (77%) had an uncomplicated pseudophakic fellow-eye history, with a routine surgery, and POD1 examination. 19 of these patients had symptomatic presentations at the POW1 timepoint, and an additional 30 had no POW1 visit at all. In total, 177 cases were included in the study, and only 4 of these cases (2.3%) had an unexpected management change at the POW1 visit. CONCLUSIONS: Asymptomatic patients who underwent uncomplicated cataract surgeries performed by resident surgeons followed by a routine POD1 visit had a low incidence of unexpected management changes at the POW1 visit. These results suggest that regularly scheduled POW1 visits could potentially be omitted for patients deemed to be at low risk for complications, and instead performed on an as-needed basis.


Assuntos
Catarata , Facoemulsificação , Humanos , Incidência , Complicações Pós-Operatórias/epidemiologia , Estudos Retrospectivos
5.
Curr Opin Ophthalmol ; 32(4): 315-318, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-33989233

RESUMO

PURPOSE OF REVIEW: Corneal nerve function is an important consideration for the refractive surgeon. In patients without a history of neuropathy, refractive surgery can lead to destruction of corneal nerves and may predispose to keratopathy. The purpose of this review is to provide an update on the effect of refractive surgery on corneal nerve function and the potential for an increased risk of neurotrophic keratopathy development. RECENT FINDINGS: Recent studies have reinforced that refractive surgery can cause anatomical and functional changes in corneal nerve function. Among the most commonly performed refractive surgery procedures are Laser Assisted In-situ Keratomileusis, Photorefractive Keratectomy, and Small Incision Lenticule Extraction. Due to differences in technique, these procedures can have varying effects on corneal nerve structure. Using in vivo confocal microscopy, postrefractive patients were found to have decreased total nerve density when compared with controls in the immediate postoperative period. In some studies, patients have been shown to undergo re-innervation and regain significant amounts of nerve function. The majority of studies have found that despite decreased nerve cell density, long-term outcomes of refractive surgery patients are generally favorable. However, loss of corneal nerve function can lead to a variety of serious effects ranging from dry eye disease, corneal hypoesthesia/anesthesia, neuropathic pain, to neurotrophic keratopathy and ulceration in the rare cases. SUMMARY: Neurotrophic keratopathy is a rare occurrence after keratorefractive surgery and is largely due to damage to corneal nerves. Proper patient selection and counseling are essential to decrease the risk of development of this devastating complication.


Assuntos
Córnea/cirurgia , Doenças da Córnea/etiologia , Ceratectomia Fotorrefrativa/efeitos adversos , Complicações Pós-Operatórias , Córnea/diagnóstico por imagem , Doenças da Córnea/diagnóstico , Humanos , Microscopia Confocal
7.
J Public Health Manag Pract ; 26 Suppl 2, Advancing Legal Epidemiology: S54-S61, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32004223

RESUMO

CONTEXT: Policy is an effective tool for reducing the health harms caused by tobacco use. State laws can establish baseline public health protections. Preemptive legislation at the state level, however, can prohibit localities from enacting laws that further protect their citizens from public health threats. APPROACH: Preemptive state tobacco control laws were assessed using the Centers for Disease Control and Prevention's State Tobacco Activities Tracking and Evaluation System. Based on the assessments, the Centers for Disease Control and Prevention quantified the number of states with certain types of preemptive tobacco control laws in place. In addition, 4 different case examples were presented to highlight the experiences of 4 states with respect to preemption. DISCUSSION: Tracking and reporting on preemptive state tobacco control laws through the Centers for Disease Control and Prevention's State Tobacco Activities Tracking and Evaluation System provide an understanding of the number and scope of preemptive laws. Case examples from Hawaii, North Carolina, South Carolina, and Washington provide a detailed account of how preemption affects tobacco control governance at state and local levels within these 4 states.


Assuntos
Saúde Pública/legislação & jurisprudência , Governo Estadual , Produtos do Tabaco/legislação & jurisprudência , Havaí , Humanos , North Carolina , Saúde Pública/tendências , South Carolina , Indústria do Tabaco/legislação & jurisprudência , Produtos do Tabaco/estatística & dados numéricos , Estados Unidos , Washington
8.
Curr Opin Ophthalmol ; 29(4): 323-327, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29794880

RESUMO

PURPOSE OF REVIEW: To perform a literature review of articles published between 2016 and 2017 to assess recent advances in intraocular lens (IOL) selection. RECENT FINDINGS: A literature review revealed five areas of recent study including advances in biometric technology, formula selection for challenging eyes, accurate astigmatic correction, adjustment of IOL calculations for postrefractive eyes with and without prerefractive surgery data, and use of intraoperative IOL calculations. SUMMARY: As cataract surgery continues to be one of the most commonly performed surgeries in the United States, it is important to ensure that the most accurate technology, IOL formula, and surgical planning is utilized.


Assuntos
Extração de Catarata , Implante de Lente Intraocular , Lentes Intraoculares , Óptica e Fotônica/métodos , Biometria/métodos , Humanos , Pseudofacia/fisiopatologia , Refração Ocular/fisiologia , Reprodutibilidade dos Testes , Acuidade Visual/fisiologia
9.
PLoS One ; 13(2): e0192381, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29408907

RESUMO

Despite improved retention and reduced complication rates paving the way for the current expansion of applications and surge in prevalence for the Boston type I Keratoprosthesis (KPro), the most frequent indication for its implantation today remains prior graft failure. The purpose of this study is to evaluate the long-term outcomes of primary KPro and compare to secondary implantation in a matched cohort study. This study included patients who underwent KPro implantation in a single center by two surgeons between July 2008 and October 2014. All eyes with KPro implantation as the primary procedure with a minimum follow up of 12 months were matched with eyes with same preoperative diagnoses that underwent secondary KPro implantation. Main outcomes included visual acuity and device retention. A total of 56 eyes were included with 28 eyes in each group. Mean follow up was 5.0 years for both groups. Twenty-nine percent (8) of the eyes in the primary group had a diagnosis of chemical or thermal injuries, 25% (7) aniridia, 18% (5) autoimmune disease, 4% (1) infectious keratitis/neurotrophic cornea, 7% (2) gelatinous corneal dystrophy, 7% (2) ectrodactyly ectodermal dysplasia/limbal stem cell deficiency, and 11% (3) uveitis/hypotony. Sixty-one percent (17) of the eyes in the primary group and 39% (11) in the secondary group maintained a final best-corrected visual acuity of 20/200 or better at a mean follow up of 5.0 years; the probability of maintaining best-corrected vision is 0.83 and 0.49 for primary and secondary groups at 5.0 years (p = 0.02). There is no statistically significant difference between groups in device retention (p = 0.22) or postoperative complication rates (p >0.05). This study demonstrates that Boston KPro implantation may be successful as a primary procedure in patients at high risk of failure with traditional penetrating keratoplasty. The device has a good long-term retention rate and visual outcomes are promising however a larger study is needed for more definitive results.


Assuntos
Ceratoplastia Penetrante/métodos , Adulto , Estudos de Casos e Controles , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Acuidade Visual
10.
J Glaucoma ; 27(2): 164-169, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29200083

RESUMO

PURPOSE: To analyze clinical outcomes and intraocular pressure control following scleral-glued intraocular lens (IOL) fixation in eyes with pseudoexfoliation (PXF). METHODS: A retrospective chart review and outcome analysis was performed on a series of eyes undergoing glue-assisted, scleral-fixated (scleral-glued) IOL insertion in the setting of PXF and poor or absent capsular support. RESULTS: In total, 28 eyes were included in the study. The indications for scleral-glued IOL fixation included late endocapsular IOL dislocation (21/28, 75%), exchange for iris-fixated IOL due to complication (4/28, 14%), subluxed crystalline lens (2/28, 7%), and aphakia after complicated cataract surgery (1/28, 4%). In total, 15/28 (54%) eyes had diagnosed preexisting glaucoma at the time of scleral-glued surgery. The most common postoperative complication was ocular hypertension requiring escalation of medical management, which occurred in 8/28 (29%) eyes. At final follow-up, corrected distance visual acuity was equivalent to or improved from preoperative measurements in 25/28 (89%) eyes. CONCLUSIONS: The scleral-glued surgery is a good option for fixating an IOL in eyes with PXF and poor zonular integrity or absent capsular support. Special attention should be placed on intraocular pressure control following surgery, which can be less predictable in PXF eyes with or without preexisting glaucoma.


Assuntos
Síndrome de Exfoliação/complicações , Pressão Intraocular/fisiologia , Implante de Lente Intraocular/métodos , Lentes Intraoculares , Esclera/efeitos dos fármacos , Adesivos Teciduais/uso terapêutico , Idoso , Idoso de 80 Anos ou mais , Síndrome de Exfoliação/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Estudos Retrospectivos , Tonometria Ocular , Resultado do Tratamento , Acuidade Visual/fisiologia
11.
Cornea ; 35(12): 1520-1525, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27755186

RESUMO

PURPOSE: To evaluate visual outcomes and complications after Descemet stripping automated endothelial keratoplasty (DSAEK) in patients with previous glaucoma surgery. METHODS: A retrospective chart review was conducted of 129 procedures in 102 eyes of 96 patients who underwent DSAEK and previous glaucoma surgery at New York Eye and Ear Infirmary of Mt Sinai. The mean length of follow-up was 29.1 ± 25.5 months. Patients with postoperative follow-up duration of less than 3 months were excluded from analysis. Intraoperative and postoperative complications, postoperative course, and visual outcomes were analyzed. RESULTS: Graft dislocation occurred in 46 eyes (35.7%) and 38 eyes required repeat injection of air in the anterior chamber. Primary graft failure occurred in 3 eyes (2.3%), early graft failure in 20 eyes (15.5%), and secondary graft failure developed in 29 eyes (22.5%). There was a statistically significant increase in secondary graft failure in patients with previous aqueous shunt implantation compared with eyes with previous trabeculectomy (P = 0.03). Escalation of glaucoma therapy was needed medically in 25 eyes (24.5%), and 8 eyes (7.8%) required additional surgical intervention. CONCLUSIONS: There is a significant incidence of graft dislocation and graft failure after DSAEK in eyes with previous glaucoma surgery. In particular, aqueous shunt surgery compared with trabeculectomy may decrease long-term graft survival, and close follow-up is warranted.


Assuntos
Doenças da Córnea/cirurgia , Ceratoplastia Endotelial com Remoção da Lâmina Limitante Posterior/métodos , Implantes para Drenagem de Glaucoma , Glaucoma/cirurgia , Complicações Intraoperatórias , Complicações Pós-Operatórias , Trabeculectomia , Idoso , Feminino , Seguimentos , Rejeição de Enxerto/diagnóstico , Rejeição de Enxerto/etiologia , Humanos , Pressão Intraocular/fisiologia , Masculino , Estudos Retrospectivos , Acuidade Visual/fisiologia
12.
J Cataract Refract Surg ; 41(9): 1839-44, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26603392

RESUMO

PURPOSE: To evaluate the visual outcomes and complications of glued foldable intraocular lens (IOL) implantation in patients with a wide range of ocular pathologies and/or having combined surgical procedures. SETTING: New York Eye and Ear Infirmary of Mount Sinai, New York, New York, USA. DESIGN: Retrospective case series. METHODS: A chart review was conducted of all glued foldable IOL procedures performed in eyes with absent or insufficient capsule support. Patients with a postoperative follow-up less than 3 months were excluded from analysis. Intraoperative and postoperative complications, the postoperative course, and visual and refractive outcomes were analyzed. RESULTS: Sixty-five eyes (64 patients) were evaluated over a mean follow-up of 9.1 months ± 6.2 (SD). Ocular comorbidities were present in 98.5% of eyes, and 95.4% had additional concurrent surgical procedures. There was a statistically significant improvement in corrected distance visual acuity (P = .046), with 89.2% of eyes achieving better or equal vision postoperatively. Intraoperative complications included ocular hemorrhage (10.8%), haptic deformation (10.8%), and haptic breakage (1.5%). Postoperative complications included elevated intraocular pressure (13.8%), optic capture (12.3%), persistent anterior chamber inflammation (6.2%), IOL tilt (4.6%), cystoid macular edema (3.1%), recurrent ocular hemorrhage (3.1%), and retinal detachment (1.5%). CONCLUSION: The glued foldable IOL technique resulted in favorable visual outcomes but with a moderate risk for IOL-related and other postoperative complications in eyes with complex ocular comorbidities having combined surgical procedures. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.


Assuntos
Transplante de Córnea , Adesivo Tecidual de Fibrina/uso terapêutico , Glaucoma/cirurgia , Complicações Intraoperatórias , Implante de Lente Intraocular/métodos , Complicações Pós-Operatórias , Adesivos Teciduais/uso terapêutico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Comorbidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pseudofacia/fisiopatologia , Refração Ocular/fisiologia , Estudos Retrospectivos , Resultado do Tratamento , Acuidade Visual/fisiologia
13.
Orbit ; 32(6): 372-4, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23895369

RESUMO

PURPOSE: To report a unique case of an orbital mass with atypical histopathologic features that although overlap with other granulomatous disorders, likely represents orbital involvement of systemic sarcoidosis. METHODS: Observational case report. RESULTS: A 51-year-old woman presented with an orbital mass and was found to have mild proptosis and restriction of ocular motility. The remainder of her ophthalmic exam was unremarkable. Excisional biopsy revealed ill-defined granulomas with central necrosis, chronic inflammation and sclerotic collagen; several features consistent with granuloma annulare. Further systemic workup including laboratory and radiologic studies were compatible with a diagnosis of systemic sarcoidosis. CONCLUSION: Our case emphasizes the importance of a complete systemic workup with the detection of an orbital granuloma to ensure accurate diagnosis and appropriate management.


Assuntos
Granuloma Anular/diagnóstico , Doenças Orbitárias/diagnóstico , Sarcoidose/diagnóstico , Biópsia , Exoftalmia/diagnóstico , Feminino , Granuloma Anular/cirurgia , Humanos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Transtornos da Motilidade Ocular/diagnóstico , Doenças Orbitárias/cirurgia , Sarcoidose/cirurgia , Tomografia Computadorizada por Raios X
14.
Cornea ; 31(12): 1436-40, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22367042

RESUMO

PURPOSE: To report the short-term visual outcomes and complications of keratoprosthesis surgery as the primary penetrating corneal procedure for patients at high risk for conventional corneal transplantation. METHODS: A retrospective chart review was conducted of 21 eyes of 19 patients who underwent either Boston keratoprosthesis type I or type II as the primary penetrating corneal procedure from February 2007 to March 2011. RESULTS: Nineteen type I (90.5%) and 2 type II (9.5%) Boston keratoprosthesis procedures were performed in 19 patients. Mean follow-up was 14.6 months (range, 6-36.3 mo). Primary indications for surgery included chemical or thermal injury, aniridia, and Stevens-Johnson syndrome. Preoperative best-corrected visual acuity (BCVA) ranged from 20/100 to light perception and was count fingers or worse in 20 eyes (95.2%). At last follow-up for all eyes, 15 eyes (71.4%) achieved BCVA≥20/200 and 4 eyes (19%) improved to BCVA≥20/50. No intraoperative complications occurred. Postoperative complications include retroprosthetic membrane formation (47.6%), cystoid macular edema (33.3%), elevated intraocular pressure (23.8%), glaucoma progression (14.3%), and endophthalmitis (4.8%). The initial keratoprosthesis was retained in 19 eyes (90.5%). CONCLUSION: The Boston keratoprosthesis, based on early follow-up, is a good alternative as a primary penetrating corneal procedure in a select group of patients with very poor prognosis for penetrating keratoplasty. Although complications can occur and require close monitoring, visual acuity significantly improved in the majority of patients.


Assuntos
Órgãos Artificiais , Córnea , Doenças da Córnea/fisiopatologia , Doenças da Córnea/cirurgia , Implantação de Prótese , Acuidade Visual/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Estudos Retrospectivos , Resultado do Tratamento
15.
Neuroophthalmology ; 36(2): 59-63, 2012 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-24031101

RESUMO

Malignant optic nerve glioma (MONG) is a rare but uniformly fatal disease that remains poorly understood. We describe a notable case of this rare disease occurring in the optic chiasm. Normal brain imaging and normal ophthalmic examination two years prior to diagnosis provide evidence for de novo genesis of MONG in our patient. Early response to steroids highlights the degree to which MONG can initially mimic inflammatory optic neuropathies and chiasmal syndromes. Our case also demonstrates a poor outcome with MONG even with current advanced therapy for glioblastoma including radiotherapy plus concomitant and adjuvant temozolomide (the EORTC/NCIC regimen) and bevacizumab.

16.
Cornea ; 29(2): 141-5, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19907286

RESUMO

PURPOSE: To evaluate the impact of Hispanic and white ethnicity on the recurrence rates of pterygia after primary excision and conjunctival autograft (CAG) in a southern California population. METHODS: A retrospective case-control review comparing 15 Hispanic and 11 white patients with primary nasal pterygia was performed. All participants received pterygium excision with superior limbal CAG by 1 of 3 surgeons and postoperative topical steroids for 2 months. The main outcome measure was recurrence after surgery, defined as fibrovascular tissue over the corneoscleral limbus onto clear cornea in the area of previous pterygium excision. RESULTS: Average duration of follow-up in the Hispanic and white groups were 9.3 +/- 9.8 months and 13.0 +/- 10.7 months, respectively (P = 0.39). During this follow-up period, there was a statistically significant difference in the pterygium recurrence rate between the Hispanic patients, 6 of 15 (40%), and the white patients, 0 of 11 (0%) (P = 0.02). The average time to recurrence was 3.4 +/- 1.1 months (range, 1.9-5.0). The difference in average age, male/female composition, and follow-up time between the Hispanic and white patient groups studied was not found to be statistically significant (P > 0.05). CONCLUSION: Hispanic ethnicity is a potentially important risk factor for recurrence of primary pterygia treated with CAG.


Assuntos
Túnica Conjuntiva/transplante , Hispânico ou Latino/etnologia , Pterígio/etnologia , População Branca/etnologia , Adulto , Idoso , Idoso de 80 Anos ou mais , California/epidemiologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Pterígio/prevenção & controle , Pterígio/cirurgia , Recidiva , Estudos Retrospectivos , Fatores de Risco , Transplante Autólogo
17.
Neurosurgery ; 62(2): 505-14; discussion 514-5, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18382330

RESUMO

OBJECTIVE: Several studies have shown that human gliomas contain a small population of cells with stem cell-like features. It has been proposed that these "cancer stem cells" may be uniquely responsible for glioma formation and recurrence. However, human gliomas also contain an abundance of cells that closely resemble more differentiated glial progenitors. Animal model studies have shown that these cells also possess the capacity to form malignant gliomas. METHODS: To investigate the contributions of stem-like and progenitor-like cells in human gliomas, we used flow cytometry to characterize the expression of a cancer stem cell marker (CD133) and a glial progenitor marker (A2B5) in 25 tumors. We found that human gliomas consistently express A2B5 in a large percentage of cells (61.7 +/- 3.8%, standard error of the mean). In contrast, CD133 expression was less abundant and less consistent (14.8 +/- 3.6%, standard error of the mean), with several glioblastomas containing very few or no detectable CD133+ cells. When present, the CD133+ population was almost entirely contained within the A2B5+ population. Thus, most gliomas could be divided into three distinct populations on the basis of these markers (A2B5+CD133+, A2B5+CD133-, and A2B5-CD133-). To test the tumorigenic potential of these populations, we separated cells from six tumors by fluorescence-activated cell sorting and reinjected them into nude rats. RESULTS: We found that the capacity for these different populations to form tumors varied depending on the human tumor specimen from which they were isolated. Of the six human gliomas tested, four contained A2B5+/CD133- cells that formed tumors when transplanted into nude rats, three contained A2B5+/CD133+ cells that formed tumors, and only one glioma contained A2B5-/CD133- cells with the capacity to form tumors. CONCLUSION: Together, these results demonstrate that human gliomas contain multiple populations of cells with the capacity to form tumors and specifically identify a population of tumorigenic A2B5+ cells that are phenotypically distinct from CD133+ cells.


Assuntos
Biomarcadores Tumorais/análise , Neoplasias Encefálicas/patologia , Gangliosídeos/metabolismo , Glioma/patologia , Células-Tronco Neoplásicas/patologia , Antígeno AC133 , Adulto , Animais , Antígenos CD/metabolismo , Neoplasias Encefálicas/metabolismo , Citometria de Fluxo , Glioma/metabolismo , Glicoproteínas/metabolismo , Humanos , Células-Tronco Neoplásicas/metabolismo , Peptídeos/metabolismo , Ratos , Ratos Nus
18.
Biochem J ; 393(Pt 1): 181-90, 2006 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-16137247

RESUMO

GCL (glutamate-cysteine ligase) is a heterodimer of a GCLC (GCL catalytic subunit) that possesses all of the enzymatic activity and a GCLM (GCL modifier subunit) that alters the K(i) of GCLC for GSH. We hypothesized that the expression of GCLM and the association of GCLM with GCLC were responsible for the apparent increase in GCL activity state observed in the liver of rats fed low-protein diets or in hepatocytes cultured in low-sulphur amino acid-containing medium. Therefore we conducted a series of studies using rats and a human hepatoma (HepG2/C3A) cell line to assess the role of GCLM and holoenzyme formation in the regulation of GCL activity in response to sulphur amino acid intake or availability. Increases in GCL activity in rat liver, as well as in HepG2 cells, were due to the additive effects of changes in the amount of GCLC and the kcat for GCLC. The increase in the kcat for GCLC was associated with increased holoenzyme formation, which was associated with an increase in the molar ratio of GCLM to GCLC. Furthermore, our results indicate that the GCLM level in rat liver is always limiting and that up-regulation of the GCLM level results in increased holoenzyme formation and an increase in the kcat. This is the first report demonstrating that the catalytic efficiency of rat GCL is increased by holoenzyme formation and the first demonstration of differential up-regulation of the GCL subunits in response to cysteine deprivation.


Assuntos
Cisteína/deficiência , Regulação Enzimológica da Expressão Gênica , Glutamato-Cisteína Ligase/biossíntese , Glutamato-Cisteína Ligase/genética , Holoenzimas/biossíntese , Animais , Domínio Catalítico , Linhagem Celular Tumoral , Cisteína/metabolismo , Proteínas Alimentares , Glutamato-Cisteína Ligase/química , Glutamato-Cisteína Ligase/metabolismo , Glutationa/metabolismo , Holoenzimas/química , Holoenzimas/genética , Humanos , Fígado/enzimologia , Masculino , Subunidades Proteicas/biossíntese , Subunidades Proteicas/química , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio
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