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1.
Ann Surg ; 275(2): e473-e478, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-32398487

RESUMO

OBJECTIVE: This study aimed to evaluate the association between prescribers' opioid prescribing history and persistent postoperative opioid use in cancer patients undergoing curative-intent surgery. BACKGROUND: Study has shown that patients may be over-prescribed analgesics after surgery. However, whether and how the prescriber's opioid prescribing behavior impacts persistent opioid use is unclear. METHODS: All adults with a diagnosis of solid cancers who underwent surgery during the study period (2009-2015) in Alberta, Canada and were opioid-naïve were included. The key exposure was the historical opioid-prescribing pattern of a patient's most responsible prescriber. The primary outcome was "new persistent postoperative opioid user," was defined as a patient who was opioid-naïve before surgery and subsequently filled at least 1 opioid prescription between 60 and 180 days after surgery. RESULTS: We identified 24,500 patients. Of these, 2106 (8.6%) patients became a new persistent opioid user after surgery. Multivariate analysis demonstrated that patients with most responsible prescribers that historically prescribed higher daily doses of opioids (≥50 vs <50 mg oral morphine equivalent) had an increased risk of new persistent opioid use after surgery (odds ratio = 2.41, P < 0.0001). In addition to the provider's prescribing pattern, other factors including younger age, comorbidities, presurgical opioid use, chemotherapy, type of tumor/surgical procedure were also found to be independently associated with new persistent postoperative opioid use. CONCLUSIONS: Our results suggest that prescriber with a history of prescribing a higher opioid dose is an important predictor of persistent postoperative opioid use among cancer patients undergoing curative-intent surgery.


Assuntos
Analgésicos Opioides/uso terapêutico , Prescrições de Medicamentos/estatística & dados numéricos , Uso de Medicamentos/estatística & dados numéricos , Neoplasias/cirurgia , Dor Pós-Operatória/tratamento farmacológico , Padrões de Prática Médica , Idoso , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório
2.
Cancers (Basel) ; 13(6)2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33809273

RESUMO

Postoperative opioid use has been linked to the subsequent development of opioid dependency. Multimodal analgesia (MMA) can reduce the use of opioids in the postoperative period, but MMA has not been well-studied after major head and neck surgery. Our goal is to explore the association between MMA and postoperative opioid use and pain control in patients undergoing major head and neck surgery. We performed a retrospective study in adult (age ≥ 18 years) patients undergoing primary head and neck cancer resection with free-flap reconstruction. All patients were treated using an established care pathway. The baseline group was treated between January 2015-December 2015 (n = 41), prior to the implementation of MMA, and were compared to an MMA-treated cohort treated between December 2017-June 2019 (n = 97). The primary outcome was the proportion of opioids prescribed and oral morphine equivalents (OMEs) consumed during the hospitalization. The secondary outcome was pain control. We found that the post-MMA group consumed fewer opioids in the postoperative period compared to the pre-MMA group. Prior to post-operative day (POD) 6, pain control was better in the post-MMA group; however, the pain control lines intersect on POD 6 and the pre-MMA group appeared to have better pain control from PODs 7-10. In conclusion, our data suggest MMA is an effective method of pain control and opioid reduction in patients undergoing surgery for head and neck cancer with free flap reconstruction. MMA use was associated with a significant decrease in the quantity of opioids consumed postoperatively. The MMA protocol was associated with improved pain management early in the postoperative course. Finally, the MMA protocol is a feasible method of pain control and may reduce the adverse side effects associated with opioid use.

3.
J Otolaryngol Head Neck Surg ; 50(1): 28, 2021 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-33892825

RESUMO

BACKGROUND: Physician opioid-prescribing patterns have significant impacts on the current opioid crisis. Patients who use opioids in the postoperative period are at risk of developing chronic postoperative opioid use. This study determined the rate of chronic postoperative opioid use among head and neck cancer patients undergoing primary surgery with free-flap reconstruction. Additionally, this study identified major risk factors associated with the development of chronic postoperative opioid use. METHODS: A retrospective chart review was performed for all adults (age ≥ 18 years) undergoing primary head and neck surgical resection with free-flap reconstruction between January 2008 and December 2015. Patients were identified from a prospectively collected database, Otobase™. Data from the provincial drug insurance program were used to capture drug dispensing information to determine chronic opioid use at 3- and 12-months postoperatively. Data extracted from Otobase™ included patient demographics, social habits, clinical stage, pathological stage, type of surgery, and adjuvant treatment. RESULTS: The total cohort was comprised of 212 patients. Chronic opioid use at 3- and 12- months postoperatively was observed in 136 (64%) and 116 (55%) patients, respectively. Of the 212 patients, 85 patients (40%) were identified as preoperative opioid users and 127 were opioid naïve (60%). Of the 85 patients who were preoperative opioid users, 70 (82%) and 63 (77%) patients continued to use opioids 3- and 12-months postoperatively, respectively. The proportion of opioid-naïve patients who were using opioids at 3- and 12-months postoperatively was 52% (66 patients) and 42% (53 patients), respectively. Identified risk factors included preoperative opioid use, prior tobacco use, advanced pathologic T-stage, and adjuvant treatment. CONCLUSIONS: Among head and neck cancer patients that have undergone major resection with free-flap reconstruction, the prevalence of chronic postoperative opioid users was considerable. Identified risk factors included preoperative opioid use, prior tobacco use, tumor stage, and adjuvant treatment.


Assuntos
Analgésicos Opioides/uso terapêutico , Neoplasias de Cabeça e Pescoço/cirurgia , Dor Pós-Operatória/tratamento farmacológico , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Dor Crônica/tratamento farmacológico , Feminino , Retalhos de Tecido Biológico , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Procedimentos de Cirurgia Plástica , Estudos Retrospectivos
4.
J Otolaryngol Head Neck Surg ; 50(1): 9, 2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33579388

RESUMO

BACKGROUND: Close margins influence treatment and outcome in patients with oral squamous cell carcinoma (OSCC). This study evaluates 187 cases of surgically treated OSCC regarding the impact of close margins on recurrence-free survival (RFS) and disease-specific survival (DSS). METHODS: Predictors of worsened outcome were identified using Kaplan-Meier analysis and multivariate Cox regression analysis. RESULTS: Tumour size [HR:1.70(0.95-3.08)], nodal status [HR:2.15(1.00-4.64)], presence of extracapsular spread (ECS) [HR:6.36(2.41-16.74)] and smoking history [HR:2.87(1.19-6.86)] were associated with worsened RFS. Similar factors were associated with worsened DSS. Close margins did not influence RFS or DSS. CONCLUSIONS: While most conventional risk factors for OSCC conferred a worsened outcome, close margins did not. One explanation for this would be that close margins (< 5 mm) are equivalent to clear margins and the cutoff definition for a close margin should be re-evaluated. Lack of standardized pathology could also reduce accuracy of reporting of close surgical margins.


Assuntos
Margens de Excisão , Neoplasias Bucais/cirurgia , Recidiva Local de Neoplasia , Carcinoma de Células Escamosas de Cabeça e Pescoço/cirurgia , Feminino , Humanos , Estimativa de Kaplan-Meier , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Neoplasias Bucais/patologia , Invasividade Neoplásica , Modelos de Riscos Proporcionais , Estudos Prospectivos , Fatores de Risco , Fumar/efeitos adversos , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Análise de Sobrevida
5.
Laryngoscope ; 130(3): 597-602, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31260128

RESUMO

OBJECTIVES/HYPOTHESIS: To determine the volumetric changes in pharyngeal structures in patients with head and neck squamous cell carcinoma (HNSCC) treated with curative chemoradiation therapy (CRT). Patients treated with CRT for esophageal carcinoma (EC), where pharyngeal structures were not part of the radiation treatment fields, were controlled for dysphagia-associated weight loss. We hypothesize that tissue volume alteration is a contributing factor of post-CRT dysphagia. STUDY DESIGN: Case series. METHODS: This study measured pre- and 1-year posttreatment volumes of the base of tongue (BOT), parapharyngeal spaces, posterior pharyngeal constrictors (PCs), and retropharyngeal space (RPS) in patients undergoing CRT for HNSCC or EC treated January 1, 2012 to December 31, 2015. All HNSCC patients were treated to doses of 66 to 70 Gy in 30 to 33 fractions using intensity-modulated radiotherapy techniques. RESULTS: Our cohort included 49 HNSCC and 11 EC patients. Within the HNSCC cohort, the PCs volume increased 1.55 cm3 (95% confidence interval [CI]: 0.77 to 2.34 cm3 , P = .0002), RPS increased 1.22 cm3 (95% CI: 0.67 to 1.77 cm3 , P < .0001), and BOT decreased 2.29 cm3 (95% CI: -0.20 to 4.79 cm3 , P = .070). The EC cohort showed no significant volumetric changes for any anatomic space, with combined PCs and RPS volume changes statistically less than the HNSCC cohort (P = .031). There was no difference in mean body mass index reduction between groups (P = .10). CONCLUSIONS: Volumetric changes following CRT may play a role in posttreatment dysphagia. Our findings support loss of physiologic function from posterior pharynx tissue thickening combined with reduced pharyngeal constriction capacity, and BOT atrophy secondary to radiation effects contribute to dysphagia. LEVEL OF EVIDENCE: 4 Laryngoscope, 130:597-602, 2020.


Assuntos
Quimiorradioterapia/efeitos adversos , Neoplasias de Cabeça e Pescoço/terapia , Faringe/patologia , Radioterapia de Intensidade Modulada/efeitos adversos , Carcinoma de Células Escamosas de Cabeça e Pescoço/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Transtornos de Deglutição/etiologia , Transtornos de Deglutição/patologia , Feminino , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Lesões por Radiação/etiologia , Lesões por Radiação/patologia , Radioterapia de Intensidade Modulada/métodos , Estudos Retrospectivos , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Resultado do Tratamento
6.
World J Surg ; 43(9): 2164-2174, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31073685

RESUMO

BACKGROUND: There are a number of studies in the literature that describe the prevalence, causes, and factors associated with chronic postoperative opioid use, but there is a lack of synthesis of the literature to guide clinicians in optimally managing postoperative pain while avoiding opioid dependence. Thus, the goal of this study was to perform a systematic review of the literature to investigate the prevalence of chronic postoperative opioid use and the associated risk factors. MATERIALS AND METHODS: A systematic search was performed using Ovid Medline and Embase according to PRISMA guidelines. Data were collected on the following outcomes of interest: prevalence of opioid use at 3, 6, and 12 months postoperatively, and risk factors associated with chronic postoperative opioid use. RESULTS: Forty-three articles were included in the final analysis. The mean prevalence of chronic postoperative opioid use in all populations at 3, 6, and 12 months postoperatively was 30.5%, 25.6%, and 25.2%, respectively. The prevalence of patients who developed chronic opioid use at 3, 6, and 12 months postoperatively was 10.4%, 8.5%, and 9.8%, respectively. Forty of the articles analyzed risk factors associated with chronic postoperative opioid use. The most common associated risk factor identified was preoperative opioid use with 27 articles demonstrating a significant association with chronic postoperative opioid use. DISCUSSION: The current opioid crisis is in part secondary to the prevalence of chronic opioid use following surgery. This study identified associated risk factors with chronic postoperative opioid use, which may help identify patients at risk for developing chronic postoperative opioid use.


Assuntos
Analgésicos Opioides/efeitos adversos , Transtornos Relacionados ao Uso de Opioides/epidemiologia , Dor Pós-Operatória/tratamento farmacológico , Analgésicos Opioides/administração & dosagem , Analgésicos Opioides/uso terapêutico , Esquema de Medicação , Humanos , Transtornos Relacionados ao Uso de Opioides/etiologia , Manejo da Dor/efeitos adversos , Manejo da Dor/métodos , Cuidados Pós-Operatórios/efeitos adversos , Prevalência , Fatores de Risco
7.
Ann Otol Rhinol Laryngol ; 127(7): 450-455, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29852749

RESUMO

OBJECTIVE: This study compares the volume of on-call otolaryngology consultations in a tertiary care center over a 5-year period. The objective of this study was to identify changes in the volume of consultations in an inpatient setting. METHODS: A cross-sectional retrospective study was performed to determine the volume of consultations. The years 2010 and 2015 were the timepoints for the cross-sectional analysis. A review of electronic medical records was performed to identify all patients associated with the otolaryngology service from the emergency department, inpatient wards, and intensive care units. The primary outcome was the number of otolaryngology consultations per year. RESULTS: The number of on-call consultations in 2010 was 992. In 2015, the number of on-call consultations was 2174. This represents a 120% increase in the number of consultations over a 5-year period ( P < .001). CONCLUSION: There has been a significant increase in the volume of on-call otolaryngology consultations at our tertiary care center. This increase has the potential to adversely affect patient care. A better understanding of the cause of this increase may allow policymakers and health care practitioners to improve patient access, physician workloads, and resource allocation.


Assuntos
Centros Médicos Acadêmicos/estatística & dados numéricos , Pacientes Internados , Otolaringologia , Otorrinolaringopatias/diagnóstico , Encaminhamento e Consulta/tendências , Centros de Atenção Terciária/estatística & dados numéricos , Carga de Trabalho/estatística & dados numéricos , Alberta , Estudos Transversais , Seguimentos , Humanos , Estudos Retrospectivos , Fatores de Tempo , Recursos Humanos
8.
J Otolaryngol Head Neck Surg ; 47(1): 29, 2018 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-29720267

RESUMO

BACKGROUND: Our study quantifies the effectiveness of perioperative pain control in a cohort of patients undergoing major head and neck surgery with free flap reconstruction. Our long-term goal is to improve pain control and thereby increase mobility, decrease postoperative complications and decrease hospital stay. METHODS: A retrospective analysis was performed at a tertiary, academic head and neck surgical oncology program in Calgary, Alberta, Canada from January 1, 2015 - December 31, 2015. Pain scores were recorded prospectively. Primary outcomes were frequency of postoperative pain assessments and pain intensity using the numeric rating scale. RESULTS: The cohort included 41 patients. Analysis was limited to pain scores recorded from postoperative days 1-14. There was an average of 7.3 pain measurements per day (SD 4.6, range 1-24) with the most frequent monitoring on postoperative days 1-4. Median pain scores ranged from 0 to 4.5 with the highest median score on postoperative day 6. The daily maximum pain scores recorded ranged from 8 to 10 with scores of 10 recorded on postoperative days 1, 2, 3, 5, 7, 8, and 10. Patients most frequently had inadequate pain control on postoperative days 1, 2, 4, and 5 with the majority occurring on postoperative day 1. CONCLUSIONS: Postoperative pain control could be improved at our centre. The frequency of pain assessments is also highly variable. Ongoing measurement, audit, and feedback of analgesic protocol effectiveness is an excellent first step in improving perioperative pain management in patients undergoing major head and neck cancer surgery with free flap reconstruction.


Assuntos
Neoplasias de Cabeça e Pescoço/cirurgia , Dor Pós-Operatória/prevenção & controle , Procedimentos de Cirurgia Plástica/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Analgésicos/uso terapêutico , Canadá , Protocolos Clínicos , Feminino , Retalhos de Tecido Biológico , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Medição da Dor , Dor Pós-Operatória/diagnóstico , Dor Pós-Operatória/etiologia , Estudos Retrospectivos , Adulto Jovem
9.
Head Neck ; 38(10): 1525-9, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27061951

RESUMO

BACKGROUND: In 2014, Alberta Health Services released guidelines for treating oral squamous cell carcinoma (OSCC). METHODS: A retrospective analysis was performed to assess the historical selection of patients with OSCC for postoperative radiotherapy (PORT) in a prospectively collected cohort of patients being treated with primary surgery. The primary outcome was compliance with the 2014 Alberta Health Services (AHS) guideline recommendations for PORT. The secondary outcome was the selection of PORT according to published pathological indications of high, intermediate, and low risk of recurrence. Reasons for discordance were analyzed. RESULT: Noncompliance with the new AHS guidelines and published indications for PORT was observed in 17% and 30% of cases, respectively. The reasons for discordance with published indications included: clinician decision (n = 41) and unmodifiable factors (n = 17). CONCLUSION: The impact of noncompliance on patient outcomes is being studied. The effect of the publication of the guidelines on selection for PORT going forward will be monitored. © 2016 Wiley Periodicals, Inc. Head Neck 38: First-1529, 2016.


Assuntos
Carcinoma de Células Escamosas/radioterapia , Fidelidade a Diretrizes/estatística & dados numéricos , Neoplasias Bucais/radioterapia , Guias de Prática Clínica como Assunto , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Escamosas/cirurgia , Terapia Combinada , Feminino , Humanos , Masculino , Margens de Excisão , Pessoa de Meia-Idade , Neoplasias Bucais/cirurgia , Estudos Retrospectivos
10.
Front Genet ; 3: 51, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22493607

RESUMO

Nitrate and nitrite are common aqueous pollutants that are known to disrupt the thyroid axis. In amphibians, thyroid hormone (TH)-dependent metamorphosis is affected, although whether the effect is acceleration or deceleration of this developmental process varies from study to study. One mechanism of action of these nitrogenous compounds is through alteration of TH synthesis. However, direct target tissue effects on TH signaling are hypothesized. The present study uses the recently developed cultured tail fin biopsy (C-fin) assay to study possible direct tissue effects of nitrate and nitrite. Tail biopsies obtained from premetamorphic Rana catesbeiana tadpoles were exposed to 5 and 50 mg/L nitrate (NO(3)-N) and 0.5 and 5 mg/L nitrite (NO(2)-N) in the absence and presence of 10 nM T(3). Thyroid hormone receptor ß (TRß) and Rana larval keratin type I (RLKI), both of which are TH-responsive gene transcripts, were measured using quantitative real time polymerase chain reaction. To assess cellular stress which could affect TH signaling and metamorphosis, heat shock protein 30, and catalase (CAT) transcript levels were also measured. We found that nitrate and nitrite did not significantly change the level of any of the four transcripts tested. However, nitrate exposure significantly increased the heteroscedasticity in response of TRß and RLKI transcripts to T(3). Alteration in population variation in such a way could contribute to the previously observed alterations of metamorphosis in frog tadpoles, but may not represent a major mechanism of action.

11.
Environ Sci Technol ; 45(12): 5395-402, 2011 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-21574574

RESUMO

Triclosan (TCS) and triclocarban (TCC) are widely used broad spectrum bactericides that are common pollutants of waterways and soils. Methyl triclosan (mTCS) is the predominant bacterial TCS metabolite. Previous studies have shown that TCS disrupts thyroid hormone (TH) action; however, the effects of mTCS or TCC are not known. The present study uses the cultured frog tadpole tail fin biopsy (C-fin) assay and the TH-responsive rat pituitary GH3 cell line to assess the effects of these three chemicals (1-1000 nM) on TH signaling and cellular stress within 48 h. mRNA abundance of TH receptor ß, Rana larval keratin type I (TH-response), heat shock protein 30, and catalase (stress-response) was measured using quantitative real-time polymerase chain reaction in the C-fin assay. The TH-responsive gene transcripts encoding growth hormone, deiodinase I, and prolactin were measured in GH3 cells with the heat shock protein 70 transcript acting as a cellular stress indicator. We found alteration of stress indicators at a wide range of concentrations of TCS, mTCS, and TCC in both test systems. mTCS and TCC affected TH-responsive gene transcripts at the highest concentration in mammalian cells, whereas a modest effect included lower concentrations in the C-fin assay. In contrast, TCS did not affect TH-responsive transcripts. These results identify nontarget biological effects of these bacteriocides on amphibian and mammalian cells and suggest the TH-disrupting effects observed for TCS could be mediated through its metabolite.


Assuntos
Carbanilidas/toxicidade , Mamíferos/fisiologia , Ranidae/fisiologia , Estresse Fisiológico/efeitos dos fármacos , Hormônios Tireóideos/farmacologia , Triclosan/análogos & derivados , Animais , Catalase/genética , Catalase/metabolismo , Linhagem Celular , Regulação da Expressão Gênica/efeitos dos fármacos , Hormônio do Crescimento/genética , Hormônio do Crescimento/metabolismo , Proteínas de Choque Térmico HSP30/genética , Proteínas de Choque Térmico HSP30/metabolismo , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/metabolismo , Iodeto Peroxidase/genética , Iodeto Peroxidase/metabolismo , Queratinas/genética , Queratinas/metabolismo , Larva/efeitos dos fármacos , Larva/genética , Técnicas de Cultura de Órgãos , Reação em Cadeia da Polimerase , Prolactina/genética , Prolactina/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ranidae/genética , Ratos , Receptores beta dos Hormônios Tireóideos/efeitos dos fármacos , Receptores beta dos Hormônios Tireóideos/metabolismo , Triclosan/toxicidade
12.
Environ Sci Technol ; 44(21): 8314-21, 2010 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-20929207

RESUMO

Nanometals are manufactured to particle sizes with diameters in the nanometer range and are included in a variety of consumer and health products. There is a lack of information regarding potential effects of these materials on aquatic organisms. Amphibians are regarded as environmental sentinels and demonstrate an exquisite sensitivity to thyroid hormone action, a hormone that is essential for human health. This present study assessed the effect of exposure to nanometals on stress and thyroid hormone signaling in frog tissue using a cultured tail fin biopsy (C-fin) assay derived from Rana catesbeiana tadpoles. The C-fin assay maintains tissue complexity and biological replication while multiple chemical responses can be assessed from the same individual. We tested the ability of nanosilver (0.06 µg/L-5.5 mg/L), quantum dots (0.25 µg/L-22 mg/L), and nanozinc oxide (0.19-10 mg/L) to alter gene expression in the presence or absence of 3,3',5'-triiodothyronine (T(3)) using quantitative real-time polymerase chain reaction. Results were compared to exposure to micrometer-silver, silver nitrate, and micrometer-cadmium telluride. Nanosilver (≥2.75 mg/L) and quantum dots (≥0.22 mg/L) altered the expression of transcripts linked to T(3)- and stress-mediated pathways, while nanozinc oxide had no effect. Lower concentrations of nanosilver (0.6 to 550 µg/L) perturbed T(3)-mediated signaling while not inducing cell stress. The observed effects were orders of magnitude below acute toxicity levels and occurred at or below the current North American water quality guidelines for metals, underscoring the need for evaluating nanoparticles separately from their constituent chemicals.


Assuntos
Nanopartículas Metálicas/toxicidade , Rana catesbeiana/metabolismo , Hormônios Tireóideos/metabolismo , Poluentes Químicos da Água/toxicidade , Animais , Larva/efeitos dos fármacos , Larva/metabolismo , Nanopartículas Metálicas/ultraestrutura , América do Norte , Pontos Quânticos , RNA Mensageiro/metabolismo , Prata/toxicidade , Estresse Fisiológico/efeitos dos fármacos , Hormônios Tireóideos/genética , Transcrição Gênica/efeitos dos fármacos , Tri-Iodotironina Reversa/metabolismo , Poluentes Químicos da Água/normas , Óxido de Zinco/toxicidade
13.
Environ Toxicol Chem ; 29(2): 380-388, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20821457

RESUMO

There is a need for the development of a rapid method for identifying chemicals that disrupt thyroid hormone (TH) action while maintaining complex tissue structure and biological variation. Moreover, no assay to date allows a simultaneous screen of an individual's response to multiple chemicals. A cultured tail fin biopsy or C-fin assay was developed using Rana catesbeiana tadpoles. Multiple tail fin biopsies were taken per tadpole, cultured in serum-free medium, and then each biopsy was exposed to a different treatment condition. The effects of known disruptors of TH action were evaluated in the C-fin assay. Chemical exposure was performed +/- 10 nM 3,3',5-triiodothyronine and real-time quantitative polymerase chain reaction (QPCR) of two TH-responsive transcripts, TH receptor beta (TRbeta) and the Rana larval keratin type I (RLKI), was performed. Within 48 h of exposure to Triac (1-100 nM), roscovitine (0.6-60 microM), or genistein (1-100 microM), perturbations in TH signaling were detected. Tetrabromobisphenol A (TBBPA) (10-1,000 nM) showed no effect. Acetochlor (1-100 nM) elicited a modest effect on the TH-dependent induction of TRbeta transcript. These data reveal that a direct tissue effect may not be critical for TBBPA and acetochlor to disrupt TH action previously observed in intact tadpoles.


Assuntos
Disruptores Endócrinos/análise , Larva/efeitos dos fármacos , Glândula Tireoide/efeitos dos fármacos , Animais , Biópsia , Genisteína/farmacologia , Bifenil Polibromatos/farmacologia , Purinas/farmacologia , Rana catesbeiana/embriologia , Roscovitina , Cauda , Toluidinas/farmacologia , Tri-Iodotironina/análogos & derivados , Tri-Iodotironina/antagonistas & inibidores , Tri-Iodotironina/farmacologia
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