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1.
OTO Open ; 8(1): e119, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38420351

RESUMO

Objective: The aim of this study is to evaluate the association between race and the treatment of laryngeal dysplasia and early-stage laryngeal squamous cell carcinoma (LSCC). Study design: Retrospective Cohort Study. Setting: Large multispecialty academic medical center. Methods: Patients were treated for laryngeal dysplasia or LSCC between September 2019 and September 2022. A retrospective chart review was conducted to collect demographic and clinical information. Two-sample t tests, chi-square tests, and linear regression models were used to compare characteristics (α = 0.05). Analyses were performed in STATA 17. Results: Sixty-five patients were identified that underwent potassium titanyl phosphate (KTP) transoral laser microsurgery for management of early-stage LSCC (n = 29) or dysplasia (n = 36). The cohort consisted of 23 Black and 42 White patients. No significant difference was found in age, alcohol or tobacco use, rate of adjuvant radiotherapy, stage of disease, nor insurance status between the 2 groups. White patients underwent more procedures to address initial disease and subsequent recurrent dysplasia on average than Black patients (2.52 vs 1.52, P = .02). This remained true after adjusting for demographic and clinical characteristics and insurance status in a linear regression model. While Black patients were more likely to be lost to follow-up than White patients (30.4% vs 9.5%, P = .03), the average number of procedures between the groups still differed significantly (2.63 vs 1.56, P = .04) when controlling for those lost to follow-up. Conclusion: The findings presented here highlight potential inequities that exist for racial minorities at early stages of treatment and in addressing premalignant conditions, which may contribute to the known downstream disparities in laryngeal cancer outcomes.

2.
JAMA Otolaryngol Head Neck Surg ; 150(2): 185, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38095882

RESUMO

This Patient Page describes the symptoms, diagnosis, and treatment of vocal cord nodules.


Assuntos
Doenças da Laringe , Pólipos , Humanos , Prega Vocal/patologia , Doenças da Laringe/diagnóstico , Doenças da Laringe/patologia , Pólipos/patologia
3.
Laryngoscope Investig Otolaryngol ; 8(3): 730-738, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37342120

RESUMO

Objectives: Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) is a common cause of late-onset ataxia that often presents with chronic cough. This study is the first to characterize the CANVAS cough both objectively and subjectively. Methods: A cross-sectional study of 13 patients was conducted. Medical records and available esophagram, modified barium swallow study, esophageal manometry, and video laryngostroboscopy data were reviewed. Leicester cough questionnaire (LCQ) and Eating Assessment Tool-10 were administered to evaluate quality of life (QoL) impairments and dysphagia symptoms, respectively. CANVAS history questionnaire was developed to characterize the clinical course. Results: 92% of patients endorsed chronic cough that preceded gait instability by a median of 16 years. Cough was dry (67%), disturbed sleep (75%), triggered by various factors, including talking, eating, and dry/spicy foods, did not respond to standard reflux therapy, and inconsistently responded to neuromodulators and superior laryngeal nerve injections. Despite perceived cough severity worsening or remaining constant in most patients, no correlation was found between cough duration and total LCQ scores. Patients reported significantly more negative social QoL impacts compared to physical QoL impacts. Ataxia duration and years of cough before ataxia symptoms were directly and inversely correlated with total LCQ scores, respectively. Imaging data revealed esophageal dysmotility (71%), vestibular penetration (57%), vestibular aspiration (14%), supraglottic compression (63%), vocal fold lesions/atrophy (50%), and arytenoid erythema (38%). Conclusion: Chronic cough is a hallmark presenting symptom in CANVAS with predominantly psychosocial QoL effects and unrecognized laryngeal alterations. In cases of idiopathic, refractory chronic cough, genetic testing for CANVAS should be considered, especially in association with sensory, cerebellar, and/or vestibular involvement. Level of evidence: VI.

4.
Am J Emerg Med ; 67: 196.e3-196.e5, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36964112

RESUMO

Emergency airway management requires matching the appropriate intubation tools to anticipated obstacles. Video laryngoscopy and flexible endoscopy are often used for difficult airways. Here we describe a case where neither method alone was anticipated to be sufficient. A 53-year-old female with an obstructing lung mass required intubation for a mixed type 1 and 2 respiratory failure. Chest x-ray revealed a tortuous subglottic obstruction. The patient could not be temporized on maximized non-invasive airway support. These factors made tandem intubation, sequentially using video laryngoscopy and flexible endoscopic intubation, an appropriate intubation strategy. In this case report we describe the rationale and technique for a rapid sequence tandem intubation.


Assuntos
Intubação Intratraqueal , Laringoscópios , Feminino , Humanos , Pessoa de Meia-Idade , Intubação Intratraqueal/métodos , Laringoscopia/métodos , Manuseio das Vias Aéreas/métodos , Indução e Intubação de Sequência Rápida
5.
Ann Otol Rhinol Laryngol ; 132(3): 351-355, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35450453

RESUMO

OBJECTIVES: Histoplasma capsulatum is a prevalent dimorphic fungus, reaching an exposure rate of 90% in endemic areas such as the Midwest and Central United States. We report an unusual presentation of dysphonia due to right vocal cord paralysis caused by mediastinal lymphadenopathy from histoplasmosis. METHODS: A 73-year-old male presented to an otolaryngology clinic with 4 months of hoarseness. Flexible strobolaryngoscopy demonstrated right vocal cord paralysis in lateral position and a full length glottic gap. Computerized tomography (CT) scan showed enlargement of a right paratracheal node. RESULTS: A lymph node biopsy was obtained and showed histoplasmosis. He was treated with a 3-month course of pozaconazole. He then received a vocal cord medialization injection 2 months after symptom onset, which produced favorable improvement of his symptoms at 8-month follow up. CONCLUSIONS: One other case report in the literature has reported left vocal cord paralysis related to histoplasmosis. This first case of right vocal cord paralysis was extremely unusual and is not often included in the differential diagnosis of vocal cord paralysis.


Assuntos
Histoplasmose , Laringe , Paralisia das Pregas Vocais , Masculino , Humanos , Idoso , Paralisia das Pregas Vocais/diagnóstico , Paralisia das Pregas Vocais/etiologia , Prega Vocal , Histoplasmose/complicações , Histoplasmose/diagnóstico , Histoplasmose/tratamento farmacológico , Rouquidão/etiologia
6.
Laryngoscope ; 132(1): 169-176, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34291467

RESUMO

OBJECTIVES/HYPOTHESIS: Laryngeal chondrosarcomas are rare malignancies with a spectrum of presentations due to varying size, local extension, and biological behavior. Moreover, these neoplasms have differing effects on respiration, phonation, and deglutition. Consequently, it is valuable to assess endoscopic and transcervical treatment strategies. STUDY DESIGN: Retrospective case series. METHODS: A retrospective review was done from 2001 to 2020; 25 patients were identified with laryngeal chondrosarcomas. Their tumor pathology and treatment were analyzed. RESULTS: All 25 chondrosarcomas were in the posterior cricoid and arose in proximity to at least one cricoarytenoid joint: 23 of 25 grade I-II (low-mid), one of 25 grade II-III (mid-high), and one of 25 grade III (high). Some tumor was left in 23 of 25 to preserve cricoarytenoid-joint function. There were no known disease-specific deaths (~8-year median follow-up). Final surgical treatment in 24 of 25 was: 13 of 25 transcervical partial laryngectomy, 7 of 25 transoral-endoscopic removal, 4 of 25 total laryngectomy, and 1 of 25 observation. CONCLUSIONS: In this series, unresected intercurrent disease with laryngeal chondrosarcomas was not life-threatening. Therefore, disease was typically left in the posterior cricoid region to preserve mobility of at least one cricoarytenoid joint. This philosophy employed an ultra-function-sparing conservation approach that preserved and/or restored optimal voice, airway patency and swallowing. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:169-176, 2022.


Assuntos
Condrossarcoma/cirurgia , Neoplasias Laríngeas/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Condrossarcoma/patologia , Cartilagem Cricoide/patologia , Cartilagem Cricoide/cirurgia , Feminino , Humanos , Neoplasias Laríngeas/patologia , Laringectomia/métodos , Laringe/patologia , Laringe/cirurgia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
7.
Respir Med ; 187: 106582, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34481304

RESUMO

Histologically benign airway strictures are frequently misdiagnosed as asthma or COPD and may present with severe symptoms including respiratory failure. A clear understanding of pathophysiology and existing classification systems is needed to determine the appropriate treatment options and predict clinical course. Clinically significant airway strictures can involve the upper and central airways extending from the subglottis to the lobar airways. Optimal evaluation includes a proper history and physical examination, neck and chest computed tomography, pulmonary function testing, endoscopy and serology. Available treatments include medical therapy, endoscopic procedures and open surgery which are based on the stricture's extent, location, etiology, morphology, severity of airway narrowing and patient's functional status. The acuity of the process, patient's co-morbidities and operability at the time of evaluation determine the need for open surgical or endoscopic interventions. The optimal management of patients with benign airway strictures requires the availability, expertise and collaboration of otolaryngologists, thoracic surgeons and interventional pulmonologists. Multidisciplinary airway teams can facilitate accurate diagnosis, guide management and avoid unnecessary procedures that could potentially worsen the extent of the disease or clinical course. Implementation of a complex airway program including multidisciplinary clinics and conferences ensures that such collaboration leads to timely, patient-centered and evidence-based interventions. In this article we outline algorithms of care and illustrate therapeutic techniques based on published evidence.


Assuntos
Laringoestenose/terapia , Sistema Respiratório/patologia , Estenose Traqueal/terapia , Broncoscopia , Constrição Patológica , Medicina Baseada em Evidências , Humanos , Laringoestenose/diagnóstico , Laringoestenose/patologia , Equipe de Assistência ao Paciente , Assistência Centrada no Paciente , Procedimentos Cirúrgicos Pulmonares , Receptor de Endotelina A , Testes de Função Respiratória , Sistema Respiratório/diagnóstico por imagem , Sistema Respiratório/fisiopatologia , Estenose Traqueal/diagnóstico , Estenose Traqueal/patologia
8.
Laryngoscope ; 131(12): 2752-2758, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34296439

RESUMO

OBJECTIVES: While it is acknowledged that otolaryngologists performing microlaryngeal surgery can develop musculoskeletal symptoms due to suboptimal body positioning relative to the patient, flexible laryngoscopy and awake laryngeal surgeries (ALSs) can also pose ergonomic risk. This prospective study measured the effects of posture during ergonomically good and bad positions during laryngoscopy using ergonomic analysis, skin-surface electromyography (EMG), and self-reported pain ratings. STUDY DESIGN: Prospective cohort study. METHODS: Eight participants trained in laryngoscopy assumed four ergonomically distinct standing positions (side/near, side/far, front/near, front/far) at three different heights (neutral-top of patient's head in line with examiner's shoulder, high-6 inches above neutral, and low-6 inches below neutral) in relation to a simulated patient. Participants' postures were analyzed using the validated Rapid Upper Limb Assessment (RULA, 1 [best] to 7 [worst]) tool for the 12 positions. Participants then simulated ALS for 10 minutes in a bad position (low-side-far) and a good position (neutral-front-near) with 12 EMG sensors positioned on the limbs and torso. RESULTS: The position with the worst RULA score was the side/near/high (7.0), and the best was the front/near/neutral (4.5). EMG measurements revealed significant differences between simulated surgery in the bad and good positions, with bad position eliciting an average of 206% greater EMG root-mean-squared magnitude across all sampled muscles compared to the good posture (paired t-test, df = 7, P < .01), consistent with self-reported fatigue/pain when positioned poorly. CONCLUSION: Quantitative and qualitative measurements demonstrate the impact of surgeon posture during simulated laryngoscopy and suggest ergonomically beneficial posture that should facilitate ALSs. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:2752-2758, 2021.


Assuntos
Ergonomia , Fadiga Muscular/fisiologia , Dor Musculoesquelética/epidemiologia , Doenças Profissionais/epidemiologia , Cirurgiões/estatística & dados numéricos , Adulto , Feminino , Humanos , Laringoscopia/efeitos adversos , Laringoscopia/métodos , Laringoscopia/estatística & dados numéricos , Masculino , Microcirurgia/efeitos adversos , Microcirurgia/métodos , Microcirurgia/estatística & dados numéricos , Pessoa de Meia-Idade , Dor Musculoesquelética/etiologia , Dor Musculoesquelética/fisiopatologia , Dor Musculoesquelética/prevenção & controle , Doenças Profissionais/etiologia , Doenças Profissionais/fisiopatologia , Doenças Profissionais/prevenção & controle , Estudos Prospectivos , Autorrelato/estatística & dados numéricos , Posição Ortostática
9.
J Voice ; 35(6): 859-868, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32362576

RESUMO

BACKGROUND: Vocal hygiene is vitally important for protecting vocal quality and promoting vocal longevity. It includes adequate hydration, avoidance of environmental irritants, and refraining from phonotraumatic behaviors such as screaming, excessive talking, and throat clearing. Formal singing training in addition to enhancing singing techniques, is also assumed to promote good vocal hygiene. Consequently, we investigated whether collegiate singers with formal training are more likely to practice good vocal hygiene habits than untrained collegiate singers. METHODS: We completed a prospective cohort study, where collegiate singers at Stanford University were voluntarily enrolled in an annual vocal health clinic. Full laryngeal exams were performed and demographic information, formal vocal training status, and information on vocal hygiene habits were obtained through questionnaires. The results were then analyzed by grouping singers as "untrained" if less than 1 year of formal training, and "trained" if greater than a year. RESULTS: A total of 82 singers were included for analysis, with 49 (59.8%) having greater than one year of formal training. Trained singers were more likely to employ a primary musical singing style of classical or operatic singing compared to untrained singers who were more likely to utilize "R&B" (P < 0.001). No significant differences were found between groups for hydration practices (P = 0.20), caffeine consumption (P = 0.73), warm up practices (P = 0.08), and phonotraumatic behaviors. Alcohol consumption, smoking tobacco, marijuana, e-cigarette usage was similar between groups. Overall, 11% of our sample reported intermittent less than daily marijuana use, with one singer reporting daily consumption. None of the singers in this sample used e-cigarettes. These rates are noticeably lower than the agematched United States population. Perceptions of cigarettes, marijuana, electronic cigarettes, alcohol, and caffeine were also the same between groups, with the vast majority of singers perceiving these agents as harmful to the voice (64%-100% depending on the agent). No laryngeal pathology was identified during laryngeal examination of any singers. CONCLUSIONS: Vocal hygiene habits are similar between trained and untrained collegiate singers. This likely relates to a desire for vocal longevity irrespective of prior training. This may dispel the long-held assumption that formal training was necessary to develop good vocal habits. We do however, present a very homogenous, highly educated sample of collegiate singers from Stanford University, having significantly less at-risk behavior than their aged-matched counterparts in the general US population. A lack of laryngeal pathology despite extensive vocal demands may also be reflective of good vocal hygiene habits.


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina , Canto , Idoso , Humanos , Higiene , Estudos Prospectivos , Universidades
10.
Otolaryngol Clin North Am ; 53(6): 1159-1170, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33039099
11.
J Voice ; 34(3): 486.e1-486.e11, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-30442529

RESUMO

OBJECTIVE: Collegiate a cappella groups have grown significantly in popularity and prominence; however, there have been few studies that evaluate the vocal health of this subgroup of young singers. The objective of this preliminary study was to conduct a multiparametric evaluation of the vocal health characteristics of a sample of collegiate a cappella singers. We further tested whether differences in vocal health assessments exist between a cappella singers with and without vocal training and trained collegiate singers who do not participate in a cappella groups. STUDY DESIGN: Point prevalence study. METHODS: Forty-one collegiate singers participated in this study. Participants were divided into the following three groups: trained singers (TS), trained a cappella singers (ATS), and untrained a cappella singers (AUS). Participants were administered a set of surveys to assess self-perception of singing voice health and perceived access and attitudes toward voice-related health care. Acoustic and laryngoscopic assessments of participant's speaking and singing voice was performed and validated vocal health questionnaires administered as a means to objectively evaluate for the presence of voice problems. RESULTS: Overall, 87.5% of the ATS and 60% of the AUS groups reported experiencing problems with their singing voice. However, no vocal abnormalities were detected during laryngoscopic and acoustic assessments. Furthermore, minimal differences between any of the measured vocal health parameters were observed between the TS, ATS, and AUS groups. CONCLUSION: Collectively, a high percentage of collegiate a cappella singers with and without vocal training report singing voice problems. However, our sample of a cappella singers did not have increased singing voice problems as compared to vocally trained collegiate singers not in a cappella groups. We did find that a cappella singers may be more inclined to seek information about maintaining a healthy singing voice from their fellow musicians as opposed to singing teachers or other voice health professionals. Singing teachers, otolaryngologists, and speech-language pathologists may need to play a more active role in educating a cappella singers regarding maintaining good vocal health.


Assuntos
Indicadores Básicos de Saúde , Canto , Estudantes , Distúrbios da Voz/diagnóstico , Qualidade da Voz , Acústica , Feminino , Humanos , Laringoscopia , Masculino , Autorrelato , Medida da Produção da Fala , Estroboscopia , Distúrbios da Voz/etiologia , Distúrbios da Voz/psicologia , Treinamento da Voz , Adulto Jovem
12.
Laryngoscope ; 128(11): 2514-2520, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29577322

RESUMO

OBJECTIVE: To determine if multispectral narrow-band imaging (mNBI) can be used for automated, quantitative detection of oropharyngeal carcinoma (OPC). STUDY DESIGN: Prospective cohort study. METHODS: Multispectral narrow-band imaging and white light endoscopy (WLE) were used to examine the lymphoepithelial tissues of the oropharynx in a preliminary cohort of 30 patients (20 with biopsy-proven OPC, 10 healthy). Low-level image features from five patients were then extracted to train naïve Bayesian classifiers for healthy and malignant tissue. RESULTS: Tumors were classified by color features with 65.9% accuracy, 66.8% sensitivity, and 64.9% specificity under mNBI. In contrast, tumors were classified with 52.3% accuracy (P = 0.0108), 44.8% sensitivity (P = 0.0793), and 59.9% specificity (P = 0.312) under WLE. Receiver operating characteristic analysis yielded areas under the curve (AUC) of 72.3% and 54.6% for classification under mNBI and WLE, respectively (P = 0.00168). For classification by both color and texture features, AUC under mNBI increased (80.1%, P = 0.00230) but did not improve under WLE (below 55% for both models, P = 0.180). Cross-validation with five folds yielded an AUC above 80% for both mNBI models and below 55% for both WLE models (P = 0.0000410 and 0.000116). CONCLUSION: Compared to WLE, mNBI significantly enhanced the performance of a naïve Bayesian classifier trained on low-level image features of oropharyngeal mucosa. These findings suggest that automated clinical detection of OPC might be used to enhance surgical vision, improve early diagnosis, and allow for high-throughput screening. LEVEL OF EVIDENCE: NA. Laryngoscope, 2514-2520, 2018.


Assuntos
Carcinoma/diagnóstico por imagem , Aprendizado de Máquina , Imagem de Banda Estreita/métodos , Neoplasias Orofaríngeas/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Teorema de Bayes , Carcinoma/patologia , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Orofaríngeas/patologia , Reconhecimento Automatizado de Padrão , Estudos Prospectivos , Sensibilidade e Especificidade
14.
Transplantation ; 95(8): 1000-7, 2013 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-23416685

RESUMO

BACKGROUND: Little is known about the immunologic events surrounding pancreatic ischemia-reperfusion injury (IRI) because of a lack of established experimental models. The purpose of this study was to develop a mouse model for pancreatic IRI to serve as a basis for the immunologic characterization of pancreatic organ damage at transplantation. METHODS: Reversible ischemia was surgically induced by vascular isolation of the distal pancreas for 0, 10, 20, or 30 min. Mice receiving laparotomy without clamping served as sham-operated controls. After reperfusion, mice were serially assayed for biochemical and histologic evidence of inflammation, proinflammatory cytokine and chemokine production, and inflammatory gene upregulation. RESULTS: After induction of pancreatic IRI, serum amylase and lactate dehydrogenase peaked at 6 hr and returned to baseline by 120 hr after injury in all groups. Mice undergoing 30 min of IRI demonstrated the greatest biochemical evidence of inflammation. Histologic scoring similarly demonstrated marked inflammation in mice subjected to 30-min IRI compared with controls. Serum cytokine/chemokine analysis demonstrated significant upregulation of granulocyte colony-stimulating factor, interferon γ, tumor necrosis factor α, interleukin (IL)-2, IL-1ß, IL-6, chemokine (C-C motif) ligand-2, chemokine (C-C motif) ligand-5, chemokine (C-X-C motif) ligand-1, and macrophage inflammatory protein 2. A similar upregulation of ccl2, il1b, il6, fos, hspa1a, hspd1, and cd14 gene expression was detected by real-time polymerase chain reaction analysis of pancreatic tissue. CONCLUSIONS: This novel model of distal pancreatic IRI in the mouse demonstrates time-limited pancreatic inflammation and injury by histologic and biochemical indices. Inflammation may be, in part, a result of the immunologic effects of IL-1ß, IL-6, and CCL-2. This model provides a method by which immunologic mechanisms of pancreatic IRI can be elucidated.


Assuntos
Quimiocina CCL2/sangue , Interleucina-1beta/sangue , Interleucina-6/sangue , Pâncreas/imunologia , Pâncreas/lesões , Traumatismo por Reperfusão/imunologia , Animais , Quimiocina CCL2/genética , Modelos Animais de Doenças , Mediadores da Inflamação/sangue , Interleucina-1beta/genética , Interleucina-6/genética , Camundongos , Camundongos Endogâmicos C57BL , Pâncreas/irrigação sanguínea , Pâncreas/patologia , Transplante de Pâncreas/efeitos adversos , Transplante de Pâncreas/imunologia , Transplante de Pâncreas/patologia , RNA/genética , RNA/metabolismo , Traumatismo por Reperfusão/sangue , Traumatismo por Reperfusão/genética , Traumatismo por Reperfusão/patologia , Regulação para Cima
15.
Nucleic Acids Res ; 40(20): 10274-86, 2012 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-22941641

RESUMO

Direct cellular DNA damage may lead to genome destabilization in unexposed, bystander, cells sharing the same milieu with directly damaged cells by means of the bystander effect. One proposed mechanism involves double strand break (DSB) formation in S phase cells at sites of single strand lesions in the DNA of replication complexes, which has a more open structure compared with neighboring DNA. The DNA in transcription complexes also has a more open structure, and hence may be susceptible to bystander DSB formation from single strand lesions. To examine whether transcription predisposes non-replicating cells to bystander effect-induced DNA DSBs, we examined two types of primary cells that exhibit high levels of transcription in the absence of replication, rat neurons and human lymphocytes. We found that non-replicating bystander cells with high transcription rates exhibited substantial levels of DNA DSBs, as monitored by γ-H2AX foci formation. Additionally, as reported in proliferating cells, TGF-ß and NO were found to mimic bystander effects in cell populations lacking DNA synthesis. These results indicate that cell vulnerability to bystander DSB damage may result from transcription as well as replication. The findings offer insights into which tissues may be vulnerable to bystander genomic destabilization in vivo.


Assuntos
Efeito Espectador , Quebras de DNA de Cadeia Dupla , Replicação do DNA , Transcrição Gênica , Animais , Encéfalo/citologia , Encéfalo/metabolismo , Células Cultivadas , Humanos , Linfócitos/metabolismo , Óxido Nítrico/metabolismo , Inibidores da Síntese de Ácido Nucleico/farmacologia , Ratos , Ratos Sprague-Dawley , Transcrição Gênica/efeitos dos fármacos , Fator de Crescimento Transformador beta/farmacologia
16.
Mutat Res ; 711(1-2): 142-9, 2011 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-21185842

RESUMO

Hibernation is an established strategy used by some homeothermic organisms to survive cold environments. In true hibernation, the core body temperature of an animal may drop to below 0°C and metabolic activity almost cease. The phenomenon of hibernation in humans is receiving renewed interest since several cases of victims exhibiting core body temperatures as low as 13.7°C have been revived with minimal lasting deficits. In addition, local cooling during radiotherapy has resulted in normal tissue protection. The experiments described in this paper were prompted by the results of a very limited pilot study, which showed a suppressed DNA repair response of mouse lymphocytes collected from animals subjected to 7-Gy total body irradiation under hypothermic (13°C) conditions, compared to normothermic controls. Here we report that human BJ-hTERT cells exhibited a pronounced radioprotective effect on clonogenic survival when cooled to 13°C during and 12h after irradiation. Mild hypothermia at 20 and 30°C also resulted in some radioprotection. The neutral comet assay revealed an apparent lack on double strand break (DSB) rejoining at 13°C. Extension of the mouse lymphocyte study to ex vivo-irradiated human lymphocytes confirmed lower levels of induced phosphorylated H2AX (γ-H2AX) and persistence of the lesions at hypothermia compared to the normal temperature. Parallel studies of radiation-induced oxidatively clustered DNA lesions (OCDLs) revealed partial repair at 13°C compared to the rapid repair at 37°C. For both γ-H2AX foci and OCDLs, the return of lymphocytes to 37°C resulted in the resumption of normal repair kinetics. These results, as well as observations made by others and reviewed in this study, have implications for understanding the radiobiology and protective mechanisms underlying hypothermia and potential opportunities for exploitation in terms of protecting normal tissues against radiation.


Assuntos
Sobrevivência Celular , Temperatura Baixa , Reparo do DNA , Linhagem Celular , Células Cultivadas , Dano ao DNA , Histonas/genética , Humanos , Hipotermia Induzida , Linfócitos/efeitos da radiação
17.
Carcinogenesis ; 30(10): 1686-95, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19651821

RESUMO

When cells are exposed to ionizing radiation (IR), unexposed cells that share media with damaged cells exhibit similar effects to irradiated cells including increased levels of DNA double-strand breaks (DSBs). Hypothesizing that this effect, known as the radiation-induced bystander effect, may be a specific instance of communication between damaged and undamaged cells regardless of damage source, we demonstrated that exposure of target cells to non-IR induces bystander damage in non-targeted cells as measured by gamma-H2AX and 53BP1 focal formation. Initially, bystander damage was found primarily in S-phase cells, but at later times, non-S-phase cells were also affected. In addition, media from undamaged malignant and senescent cells also was found to induce DSBs in primary cultures. Media conditioned on cells targeted with either ionizing or non-IR as well as on undamaged malignant and senescent cells contained elevated levels of several cytokines. One of these, transforming growth factor beta (TGF-beta), and nitric oxide (NO) were found to elevate numbers of gamma-H2AX/53BP1 foci in normal cell cultures similar to levels found in bystander cells, and this elevation was abrogated by NO synthase inhibitors, TGF-beta blocking antibody and antioxidants. These findings support the hypothesis that damage in bystander cells results from their exposure to cytokines or reactive compounds released from stressed cells, regardless of damage source. These results have implications for oncogenesis in that they indicate that damaged normal cells or undamaged tumor cells may induce genomic instability, leading to an increased risk of oncogenic transformation in other cells with which they share media or contact directly.


Assuntos
Comunicação Celular/fisiologia , Histonas/genética , Mama/citologia , Mama/fisiologia , Divisão Celular/efeitos da radiação , Transformação Celular Neoplásica , DNA de Neoplasias/genética , Inibidores Enzimáticos/farmacologia , Feminino , Fibroblastos/citologia , Fibroblastos/fisiologia , Células HeLa/citologia , Células HeLa/fisiologia , Células HeLa/efeitos da radiação , Histonas/metabolismo , Humanos , Óxido Nítrico/farmacologia , Óxido Nítrico Sintase/antagonistas & inibidores , Fase S , Estresse Fisiológico/fisiologia , Fator de Crescimento Transformador beta/farmacologia , Raios Ultravioleta , Neoplasias do Colo do Útero/genética
18.
Chromosoma ; 118(6): 683-92, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19707781

RESUMO

Upon DNA double-strand break (DSB) induction in mammals, the histone H2A variant, H2AX, becomes rapidly phosphorylated at serine 139. This modified form, termed gamma-H2AX, is easily identified with antibodies and serves as a sensitive indicator of DNA DSB formation. This review focuses on the potential clinical applications of gamma-H2AX detection in cancer and in response to other cellular stresses. In addition, the role of H2AX in homeostasis and disease will be discussed. Recent work indicates that gamma-H2AX detection may become a powerful tool for monitoring genotoxic events associated with cancer development and tumor progression.


Assuntos
Histonas/metabolismo , Animais , Biomarcadores/metabolismo , Dano ao DNA , Doença , Saúde Ambiental , Humanos , Fatores de Risco
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