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1.
Pediatr Blood Cancer ; 65(3)2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29115718

RESUMO

BACKGROUND: Young children with posterior fossa ependymoma (PF-EPN) have a worse prognosis than older children, and they have a unique molecular profile (PF-EPN-A subtype). Alternative treatment strategies are often used in these young patients, and their prognostic factors are less clear. METHODS: We characterized the prognostic factors and treatment outcomes of 482 patients between ages 0 and 3 years with the diagnosis of ependymoma identified from the Surveillance, Epidemiology, and End Results registry (1973-2013). RESULTS: Radiation therapy (RT) was delivered to 52.3% of patients, and gross total resection (GTR) was performed in 51.0% of patients. Overall survival (OS) at 10 years was 48.4% with median follow-up of 3.3 years. WHO grade was not predictive of OS. Extent of resection was significant for survival; the 10-year OS with GTR was 61.0%, and with subtotal resection (STR) and biopsy was 38.2% and 35.0%, respectively (P < 0.001). RT significantly benefitted OS for both grades II and III. The 10-year OS for grade II was 50.5% with RT and 43.4% without (P = 0.030); 10-year OS for grade III was 66.0% with RT and 40.0% without (P = 0.002). Multivariate analysis showed significantly improved OS with RT (hazard ratio [HR] 0.601, 95% CI: 0.439-0.820, P = 0.001) and GTR (HR 0.471, 95% CI: 0.328-0.677, P < 0.0001). CONCLUSIONS: Ependymoma outcomes in patients within 0-3 years of age significantly improved with RT and GTR. Histopathologic grading of ependymoma demonstrated no prognostic significance. Given the poor OS for this population and unique genetic profile, future prospective studies with molecular-based stratification should be performed to evaluate additional prognostic factors.


Assuntos
Ependimoma/radioterapia , Ependimoma/cirurgia , Neoplasias Infratentoriais/radioterapia , Neoplasias Infratentoriais/cirurgia , Pré-Escolar , Ependimoma/mortalidade , Feminino , Humanos , Lactente , Recém-Nascido , Neoplasias Infratentoriais/mortalidade , Masculino , Prognóstico , Intervalo Livre de Progressão , Programa de SEER , Resultado do Tratamento
2.
Ann Oncol ; 27(7): 1336-41, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27052656

RESUMO

BACKGROUND: Squamous cell cancers of the anal canal (ASCC) are increasing in frequency and lack effective therapies for advanced disease. Although an association with human papillomavirus (HPV) has been established, little is known about the molecular characterization of ASCC. A comprehensive genomic analysis of ASCC was undertaken to identify novel genomic alterations (GAs) that will inform therapeutic choices for patients with advanced disease. PATIENTS AND METHODS: Hybrid-capture-based next-generation sequencing of exons from 236 cancer-related genes and intronic regions from 19 genes commonly rearranged in cancer was performed on 70 patients with ASCC. HPV status was assessed by aligning tumor sequencing reads to HPV viral genomes. GAs were identified using an established algorithm and correlated with HPV status. RESULTS: Sixty-one samples (87%) were HPV-positive. A mean of 3.5 GAs per sample was identified. Recurrent alterations in phosphoinositol-3-kinase pathway (PI3K/AKT/mTOR) genes including amplifications and homozygous deletions were present in 63% of cases. Clinically relevant GAs in genes involved in DNA repair, chromatin remodeling, or receptor tyrosine kinase signaling were observed in 30% of cases. Loss-of-function mutations in TP53 and CDKN2A were significantly enhanced in HPV-negative cases (P < 0.0001). CONCLUSIONS: This is the first comprehensive genomic analysis of ASCC, and the results suggest new therapeutic approaches. Differing genomic profiles between HPV-associated and HPV-negative ASCC warrants further investigation and may require novel therapeutic and preventive strategies.


Assuntos
Neoplasias do Ânus/genética , Carcinoma de Células Escamosas/genética , Inibidor de Quinase Dependente de Ciclina p18/genética , Genômica , Proteína Supressora de Tumor p53/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias do Ânus/patologia , Neoplasias do Ânus/virologia , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/virologia , Inibidor p16 de Quinase Dependente de Ciclina , Éxons/genética , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Proteínas de Neoplasias/genética , Proteínas Nucleares/genética , Papillomaviridae/genética , Papillomaviridae/isolamento & purificação , Papillomaviridae/patogenicidade , Fatores de Transcrição/genética
3.
Endoscopy ; 44(6): 590-5, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22638780

RESUMO

BACKGROUND AND STUDY AIMS: It is critical that the risk of lymph node metastasis (LNM) is evaluated for determining the suitability of endoscopic resection for T1 colorectal cancer (CRC). Reported risk factors for LNM in completely resected T1 CRC are deep submucosal invasion, grade 3, angiolymphatic invasion, and budding. The aim of the present study was to identify the histopathologic factors associated with LNM in T1 CRC. PATIENTS AND METHODS: The study involved 435 patients with T1 CRC treated by endoscopic or surgical resection between January 2001 and April 2010 at the National Cancer Center, Korea. The 435 patients were classified into two groups - those undergoing surgical resection (n = 324) and those undergoing endoscopic resection (n = 111). In the surgically resected group, details regarding depth of submucosal invasion, angiolymphatic invasion, tumor grade, budding, and background adenoma (BGA) were evaluated with respect to presence or absence of LNM. In the endoscopically resected group, the results of follow-ups and additional salvage surgeries were studied. RESULTS: In the surgically resected group, LNM was detected in 42 patients (13.0 %). Grade 3, angiolymphatic invasion, budding, and the absence of BGA were identified as factors associated with LNM in univariate and multivariate analyses (P < 0.05). Among the 50 patients in the endoscopically resected group with high risk, three were diagnosed as being LNM-positive during the follow-up period. There was no LNM in the endoscopically resected group with low risk. CONCLUSIONS: Grade 3, angiolymphatic invasion, budding, and the absence of BGA are the risk factors that predict LNM in patients with T1 CRC. In cases where endoscopically resected T1 CRC has no risk factor, cautious follow-up could be recommended. However, if the tumor has any risk factor, additional surgical resection should be considered.


Assuntos
Adenocarcinoma/patologia , Adenoma/patologia , Neoplasias Colorretais/patologia , Endoscopia Gastrointestinal , Adenocarcinoma/cirurgia , Adenoma/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Vasos Sanguíneos/patologia , Distribuição de Qui-Quadrado , Neoplasias Colorretais/cirurgia , Feminino , Humanos , Modelos Logísticos , Metástase Linfática , Vasos Linfáticos/patologia , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Invasividade Neoplásica , Estudos Retrospectivos , Fatores de Risco
4.
J Viral Hepat ; 18(10): e432-8, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21914060

RESUMO

No studies have reported the long-term effects of entecavir switching in patients with multidrug resistance who developed resistance after lamivudine/adefovir sequential therapy. We evaluated the efficacy of 96 weeks of entecavir therapy in patients with resistance to lamivudine/adefovir sequential therapy. In total, 33 patients with chronic hepatitis B virus (HBV) infection with evidence of active viral replication (HBV DNA levels ≥ 10(5) copies/mL) or a history of treatment failure to lamivudine/adefovir sequential therapy between April 2007 and July 2009 were treated with entecavir (1.0 mg daily) for at least 48 weeks. The rates of alanine transaminase (ALT) normalization and HBV DNA negativity were 66.7% (14/21) and 24.2% (8/33) at 48 weeks, respectively. The initial HBV DNA level was the only factor that was inversely associated with serum HBV DNA negativity after 48 weeks of entecavir therapy (P < 0.023). At 96 weeks, the rates of ALT normalization and HBV DNA negativity were 77.8% (7/9) and 16.7% (3/18), respectively. Viral breakthrough occurred in 21.2% (7/33) and 78.9% (15/19) of patients at 48 and 96 weeks, respectively. Patients who achieved a HBV DNA level of <4 log(10) copies/mL at 48 weeks maintained a similar HBV DNA level and a normal ALT level until 96 weeks. Entecavir monotherapy for 96 weeks was not efficacious for patients with lamivudine/adefovir-resistant HBV. The initial HBV DNA level was the only predictive factor for antiviral efficacy. However, patients who achieved a HBV DNA level of <4 log(10) copies/mL with a normal ALT level at 48 weeks should maintain, rather than stop, entecavir therapy.


Assuntos
Antivirais/administração & dosagem , Farmacorresistência Viral , Guanina/análogos & derivados , Vírus da Hepatite B/efeitos dos fármacos , Hepatite B Crônica/tratamento farmacológico , Adenina/administração & dosagem , Adenina/análogos & derivados , Adulto , Idoso , Alanina Transaminase/sangue , Antivirais/farmacologia , DNA Viral/sangue , Feminino , Guanina/administração & dosagem , Humanos , Lamivudina/farmacologia , Testes de Função Hepática , Masculino , Pessoa de Meia-Idade , Organofosfonatos/administração & dosagem , Estudos Retrospectivos , Resultado do Tratamento , Carga Viral
5.
Xenobiotica ; 41(5): 409-15, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21250786

RESUMO

After both the intravenous and oral administration of zinc acexamate [ZAC; ion-pairing between zinc and ϵ-acetamidocaproic acid (AACA)] and cimetidine together, the areas under the curve (AUCs) of AACA were significantly greater [by 28.2 and 98.9% after the intravenous and oral administration, respectively, for control rats and 13.5 and 16.9% for indomethacin-induced acute gastric ulcer (IAGU) rats, respectively] than those of ZAC alone due to the significantly slower renal clearance (CL(R)). The significantly greater AUCs of AACA after both the intravenous and oral administration of ZAC and cimetidine together in control and IAGU rats could have been due to the inhibition of active renal tubular secretion of AACA by cimetidine. After the intravenous and oral administration of both drugs together, the AUCs of cimetidine in control and IAGU rats were not different compared with those with cimetidine alone.


Assuntos
Aminocaproatos , Cimetidina/farmacocinética , Cimetidina/uso terapêutico , Rim/metabolismo , Úlcera Gástrica/tratamento farmacológico , Administração Oral , Ácido Aminocaproico/administração & dosagem , Ácido Aminocaproico/sangue , Ácido Aminocaproico/farmacocinética , Ácido Aminocaproico/uso terapêutico , Animais , Antiulcerosos/administração & dosagem , Antiulcerosos/farmacocinética , Antiulcerosos/uso terapêutico , Proteínas Sanguíneas/metabolismo , Cimetidina/administração & dosagem , Diálise , Interações Medicamentosas , Indometacina , Injeções Intravenosas , Masculino , Ligação Proteica , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
6.
Xenobiotica ; 41(10): 885-94, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21623701

RESUMO

Protein-calorie malnutrition (PCM) occurs frequently in advanced cancer patients and has a profound impact on the toxicity of many drugs. Thus, the pharmacokinetics of etoposide were evaluated in control, control with cysteine (CC), PCM, and PCM with cysteine (PCMC) rats. Etoposide was administered intravenously (2 mg/kg) or orally (10 mg/kg). Changes in hepatic and intestinal cytochrome P450s (CYPs) and effects of cysteine on intestinal P-glycoprotein (P-gp)-mediated efflux were also measured. In PCM rats, the CL(NR) (AUC(0-∞)) of intravenous etoposide was significantly slower (greater) than that in controls, because of the significant decrease in the hepatic CYP3A subfamily and P-gp. In PCMC rats, the slowed CL(NR) of etoposide in PCM rats was restored to the control level by cysteine treatment. PCMC rats showed a significantly greater AUC(0-6 h) of oral etoposide than PCM rats, primarily because of the increased gastrointestinal absorption of etoposide as a result of the inhibition of intestinal P-gp by cysteine. The gastrointestinal absorption of an oral anticancer drug, which is a substrate of P-gp, may be improved by co-administration of cysteine in advanced cancer patients if the present rat data can be extrapolated to patients.


Assuntos
Antineoplásicos Fitogênicos/farmacocinética , Cisteína/farmacologia , Etoposídeo/farmacocinética , Trato Gastrointestinal/metabolismo , Absorção Intestinal/efeitos dos fármacos , Desnutrição Proteico-Calórica/metabolismo , Animais , Antineoplásicos Fitogênicos/química , Citocromo P-450 CYP3A/metabolismo , Ingestão de Alimentos/efeitos dos fármacos , Etoposídeo/química , Masculino , Permeabilidade/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Aumento de Peso/efeitos dos fármacos
7.
Xenobiotica ; 40(7): 485-98, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20518623

RESUMO

1. Zinc acexamate (ZAC) is ionized to zinc and epsilon-acetamidocaproic acid (AACA). Thus, the pharmacokinetics and tissue distribution of zinc and AACA after intravenous (50 mg kg(-1)) and oral (100 mg kg(-1)) administration of ZAC were evaluated in rats. Also the pharmacokinetics of AACA after intravenous (10, 20, 30, and 50 mg kg(-1)) and oral (20, 50, and 100 mg kg(-1)) administration of ZAC and the first-pass extractions of AACA at a ZAC dose of 20 mg kg(-1) were evaluated in rats. 2. After oral administration of ZAC (20 mg kg(-1)), approximately 0.408% of the oral dose was not absorbed, the F value was approximately 47.1%, and the hepatic and gastrointestinal (GI) first-pass extractions of AACA were approximately 8.50% and 46.4% of the oral dose, respectively. The incomplete F value of AACA was mainly due to the considerable GI first-pass extraction in rats. 3. Affinity of rat tissues to zinc and AACA was low-the tissue-to-plasma (T/P) ratios were less than unity. The equilibrium plasma-to-blood cells partition ratios of AACA were independent of initial blood ZAC concentrations of 1, 5, and 10 microg ml(-1)-the mean values were 0.481, 0.490, and 0.499, respectively. The bound fractions of zinc and AACA to rat plasma were 96.6% and 39.0%, respectively.


Assuntos
Aminocaproatos , Antiulcerosos/farmacocinética , Administração Oral , Ácido Aminocaproico/administração & dosagem , Ácido Aminocaproico/sangue , Ácido Aminocaproico/química , Ácido Aminocaproico/metabolismo , Ácido Aminocaproico/farmacocinética , Animais , Antiulcerosos/administração & dosagem , Antiulcerosos/metabolismo , Relação Dose-Resposta a Droga , Estrutura Molecular , Ratos , Distribuição Tecidual
8.
J Int Med Res ; 37(6): 1772-9, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-20146875

RESUMO

Coronary artery bypass graft (CABG) patients often have cerebrovascular disease and pre-operative brain magnetic resonance angiography (MRA) frequently reveals cerebral vasculature stenosis. This study was designed to investigate whether pre-operative MRA findings correlated with regional cerebral oxygen saturation (ScO(2)) in 120 patients undergoing on-pump or off-pump CABG. Following MRA examination, patients were divided into six groups of 20 patients each based on MRA findings (no stenosis, mild stenosis or severe stenosis) and procedure (on-pump or off-pump CABG). Mean ScO(2) values over 3 min were determined at seven periods during surgery. Patients with severe cerebrovascular stenosis showed significantly lower ScO(2) than other groups during off-pump CABG. During on-pump CABG, ScO(2) decreased significantly during cardiopulmonary bypass in all groups and was significantly lower in the severe stenosis group. Pre-operative MRA and intra-operative ScO(2) monitoring may help to identify patients at increased risk of brain damage during or following CABG.


Assuntos
Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Ponte de Artéria Coronária , Angiografia por Ressonância Magnética , Oxigênio/metabolismo , Período Pré-Operatório , Demografia , Feminino , Humanos , Período Intraoperatório , Masculino , Pessoa de Meia-Idade , Radiografia
9.
Indian J Cancer ; 46(2): 96-107, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19346643

RESUMO

The incidence of gliomas is increasing worldwide, including India. Of the 18,820 new cases of primary central nervous system (CNS) tumors diagnosed annually in the United States, gliomas account for over 60% with 30-40% of them being glioblastoma multiforme (GBM), 10% being anaplastic astrocytoma (AA), and 10% being low grade gliomas (LGGs). This is in contrast to one study from West Bengal, India, in which only 7.9% of the brain tumors were GBMs, while 46.8% were astrocytomas. Of all adult primary CNS tumors, GBM is the most common and the most malignant with about 7,000 to 8,000 new cases annually in the United States. Given poor outcomes, a number of treatment approaches have been investigated. Common to these approaches is the use of adjuvant radiation therapy, even as surgery alone, with or without chemotherapy, may be the mainstay for some lower grade and low-risk gliomas. Today, treatment typically involves external beam radiation, with concurrent and adjuvant chemotherapy for more aggressive histologies. Although gliomas are relatively uncommon, active research is ongoing. Results of landmark trials along with some of the recently published trials are presented. These trials and management strategies as well as evolving concepts are found by reviewing over 200 articles in the National Library Medical (NLM) database, PubMed, more than 60 of which are refrenced. Specifically, the database is searched using the following keywords, with various combinations: glioma, low-grade, anaplastic, astrocytoma, oligodendroglioma, oligoastrocytoma, glioblastoma multiforme, chemotherapy, radiation, new concepts, phase III, MGMT, CDX-110 (Celldex), temozolomide, 1p/19q deletion, and bevacizumab.


Assuntos
Neoplasias do Sistema Nervoso Central/terapia , Quimioterapia Adjuvante , Medicina Baseada em Evidências , Glioma/terapia , Radioterapia Adjuvante , Antineoplásicos/uso terapêutico , Astrocitoma/tratamento farmacológico , Astrocitoma/radioterapia , Astrocitoma/terapia , Neoplasias do Sistema Nervoso Central/tratamento farmacológico , Neoplasias do Sistema Nervoso Central/radioterapia , Glioblastoma/tratamento farmacológico , Glioblastoma/radioterapia , Glioblastoma/terapia , Glioma/tratamento farmacológico , Glioma/radioterapia , Humanos
10.
Transplant Proc ; 40(8): 2832-4, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18929875

RESUMO

Simultaneous liver and kidney transplantation (SLKT) is now considered the treatment of choice for patients with concurrent end-stage liver and kidney diseases. Even though the early postoperative mortality rate following SLKT is reported to be high compared to that of liver transplantation alone, the liver graft from the same donor has been argued to induce better kidney graft acceptance as evidenced by a low rate of acute renal rejection episodes. There have been many reports of a low incidence of acute renal rejection following SLKT; however, only a few cases were proven by simultaneous biopsies. The authors experienced a case of biopsy-proven isolated acute cellular rejection of the liver graft following SLKT.


Assuntos
Rejeição de Enxerto/diagnóstico , Imunossupressores/uso terapêutico , Transplante de Rim/imunologia , Transplante de Fígado/imunologia , Hemissuccinato de Metilprednisolona/uso terapêutico , Doença Aguda , Biópsia , Humanos , Inflamação , Transplante de Rim/patologia , Circulação Hepática , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
11.
J Chromatogr B Analyt Technol Biomed Life Sci ; 1061-1062: 292-299, 2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28772225

RESUMO

Colorectal cancer (CRC) is a leading cause of cancer mortality. Diet has a significant influence on colon cancer risk. Identifying chemopreventive agents, dietary constituents, practices and/or diet supplements that promote gut health and reduce the incidence of intestinal neoplasias and CRC could significantly impact public health. Sphingadienes (SDs) are dietary sphingolipids found in plant-based food products. SDs are cytotoxic to colon cancer cells and exhibit chemopreventive properties. The aim of the present study was to develop a sensitive and robust ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for quantifying SDs in food products and biological samples. The assay was linear over a concentration range of 80nM to 50µM and was sensitive to a detection limit of 3.3nM. Post-extraction stability was 100% at 24h. SD content in soy oils was approximately 10nM. SDs were detected transiently in the plasma of adult mice 10min after gavage delivery of a 25mg/kg bolus and declined to baseline by 1h. SD uptake in the gut was maximal in the duodenum and peaked 1h after gavage delivery. Disappearance of SDs in the lower gastrointestinal tract suggests either rapid metabolism to yet unidentified products or potentially luminal export.


Assuntos
Cromatografia Líquida/métodos , Etanolaminas/análise , Análise de Alimentos/métodos , Esfingolipídeos/análise , Animais , Etanolaminas/farmacocinética , Absorção Intestinal , Limite de Detecção , Modelos Lineares , Camundongos , Reprodutibilidade dos Testes , Alimentos de Soja/análise , Esfingolipídeos/farmacocinética , Espectrometria de Massas em Tandem/métodos
13.
Circulation ; 100(3): 219-21, 1999 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-10411842

RESUMO

BACKGROUND: In the presence of atherosclerosis, the coronary endothelial vasomotor response to acetylcholine is frequently abnormal but is variable between patients. We tested the hypothesis that the plasma concentration of alpha-tocopherol is associated with the preservation of nitric oxide-mediated endothelium-dependent vasomotion. METHODS AND RESULTS: We studied 15 men and 6 women (mean age 61+/-10 years) at coronary angiography who were not taking vitamin supplements. Coronary endothelium-dependent and -independent vasomotion was assessed by intracoronary infusions of acetylcholine and nitroglycerin. The vasomotor responses were compared with the plasma concentration of alpha-tocopherol and the plasma alpha-tocopherol concentration relative to total lipid (total cholesterol plus triglycerides). The mean plasma alpha-tocopherol was 25.6+/-6.1 micromol/L, total cholesterol 193+/-27 mg/dL, triglycerides 115+/-66 mg/dL, and alpha-tocopherol to total lipid 4. 2+/-0.9 micromol. L(-1). (mmol/L)(-1). The mean vasomotor response to acetylcholine was -1% (range -33% to 28%) and to nitroglycerin 22% (range 0% to 54%). Plasma alpha-tocopherol was significantly correlated with the acetylcholine response (r=0.49, P<0.05) but not the nitroglycerin response (r=0.13, P>0.05). The acetylcholine response remained significant after adjustment for other potential sources of oxidant stress (total cholesterol, diabetes mellitus, smoking, angina class) (P<0.01). The relative concentration of alpha-tocopherol to total lipid was not related to endothelial function (r=0.24, P=0.3, n=20). CONCLUSIONS: alpha-Tocopherol may preserve endothelial vasomotor function in patients with coronary atherosclerosis. This effect may be related primarily to the action of alpha-tocopherol in the vascular wall. Further studies that assess the impact of alpha-tocopherol supplementation as therapy of endothelial dysfunction are justified.


Assuntos
Doença da Artéria Coronariana/fisiopatologia , Vasos Coronários/fisiologia , Sistema Vasomotor/fisiologia , Vitamina E/sangue , Acetilcolina , Colesterol/sangue , Doença da Artéria Coronariana/sangue , Vasos Coronários/efeitos dos fármacos , Endotélio Vascular/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nitroglicerina , Triglicerídeos/sangue , Sistema Vasomotor/efeitos dos fármacos
14.
Curr Med Chem ; 11(9): 1135-46, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15134511

RESUMO

alpha-Lipoic acid (LA), a naturally occurring dithiol compound, has long been known as an essential cofactor for mitochondrial bioenergetic enzymes. Aside from its enzymatic role, in vitro and in vivo studies suggest that LA also acts as a powerful micronutrient with diverse pharmacologic and antioxidant properties. Pharmacologically, LA improves glycemic control, polyneuropathies associated with diabetes mellitus, and effectively mitigates toxicities associated with heavy metal poisoning. As an antioxidant, LA directly terminates free radicals, chelates transition metal ions (e.g. iron and copper), increases cytosolic glutathione and vitamin C levels and prevents toxicities associated with their loss. These diverse actions suggest that LA acts by multiple mechanisms both physiologically and pharmacologically, many of which are only now being explored. Herein, we review the known biochemical properties of LA with particular reference to how LA may be an effective agent to ameliorate certain pathophysiologies of many chronic diseases.


Assuntos
Antioxidantes/farmacologia , Estresse Oxidativo , Ácido Tióctico/análogos & derivados , Ácido Tióctico/farmacologia , Animais , Antioxidantes/uso terapêutico , Terapia por Quelação , Doença Crônica , Coenzimas/farmacologia , Neuropatias Diabéticas/tratamento farmacológico , Sequestradores de Radicais Livres/farmacologia , Intoxicação do Sistema Nervoso por Metais Pesados/prevenção & controle , Humanos , Metais Pesados , Espécies Reativas de Nitrogênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Ácido Tióctico/química , Ácido Tióctico/uso terapêutico
15.
Int J Radiat Oncol Biol Phys ; 32(3): 809-13, 1995 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-7790268

RESUMO

PURPOSE: To investigate the use of asymmetric collimators and a single isocenter for delivering a uniform, accurate dose of radiation to the head, neck, and supraclavicular lymph nodes. METHODS AND MATERIALS: A linear accelerator with a pair of asymmetric collimators is required for this technique. An isocenter was placed at the junction of the lateral head and neck fields and the anterior supraclavicular field. The asymmetric collimators were set longitudinally, by collimator rotation if necessary. The collimators split the radiation beam to all portals. Dose uniformity was measured at the junction with films in solid-water phantoms. RESULTS: Film dosimetry showed a uniform dose at the junction without hot or cold regions. A digital display tolerance of +/- 1.0 mm for a field size maintained an acceptable uniform dose (+/- 5% dose variation) at the junction. The single isocenter and asymmetric collimators reduced field setup time by half. No table rotation was required to match fields. CONCLUSION: The asymmetric collimators lead to easy and accurate patient setup. The absence of the trapezoid effect resulted in the complete coverage of the submandibular and cervical nodes without any hot spots.


Assuntos
Neoplasias de Cabeça e Pescoço/radioterapia , Aceleradores de Partículas/instrumentação , Humanos , Dosagem Radioterapêutica
16.
Int J Radiat Oncol Biol Phys ; 43(5): 1037-41, 1999 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-10192352

RESUMO

PURPOSE: To design a practical breast shield and to investigate its efficacy in reducing scattered radiation to the contralateral breast of patients undergoing radiation therapy for breast cancer. METHODS AND MATERIALS: We constructed a mobile shield consisting of (a) a mobile base and a counterweight; (b) a vertical column adjustable in height and a diagonal arm adjustable in angle; (c) a curved, 2.5-cm thick lead sheet with a 1-cm thick polystyrene liner for blocking scattered radiation; and (d) diode detectors to verify that the edge of the lead sheet is not in the useful beam in addition to the use of the field light. Measurements were performed with thermoluminescent dosimeters on 10 patients without the shield and on an anthropomorphic phantom with a pair of wax breasts with and without the shield. All of the patients were treated with 6-MV photons (Varian 6/100). The scattered radiation from the medial and lateral fields was measured separately. RESULTS: The contribution of the medial field to the total scattered dose was 70% to 75%, whether a medial wedge was used or not. However, without a medial wedge, the scattered dose was reduced by nearly 33% at 3 to 9 cm away from the medial border. In the anthropomorphic phantom study with wax breast, the mobile shield reduced the medial field contribution to the total scatter dose to less than the contribution from the lateral field without a shield. With a prescribed dose of 50 Gy and a medial wedge, the median scatter dose to the contralateral breast from 6 patients was 5.3 Gy; without a medial wedge, it was 3.8 Gy from 4 patients at 6 cm from the medial border. In the phantom study, with the shield the total dose to the contralateral breast was 1.0 Gy at 6 cm from the medial border with a same prescribed dose. CONCLUSION: The mobile shield reduced the scatter dose to the contralateral breast from the linear accelerator (Varian 6/100, 6-MV photons) by a factor of 3 to 4. The shield greatly reduced the scattered dose in the wax phantom. Equivalent reductions in patients may be clinically significant by reducing the risk of radiation-induced breast cancer in the contralateral breast of woman undergoing radiation therapy for breast cancer. The shield is safe and easy to adjust to each patient.


Assuntos
Neoplasias da Mama/radioterapia , Mama/efeitos da radiação , Lesões por Radiação/prevenção & controle , Proteção Radiológica/instrumentação , Desenho de Equipamento , Feminino , Humanos , Espalhamento de Radiação
17.
Int J Radiat Oncol Biol Phys ; 32(3): 831-7, 1995 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-7790271

RESUMO

PURPOSE: Three-dimensional treatment planning was performed to evaluate three standard coplanar irradiation techniques (two-field parallel-opposed, three-field, and 110 degrees bilateral arcs), the 330 degrees single rotational arc, and a four noncoplanar arc technique for the treatment of pituitary adenomas. We sought to identify the optimal technique for minimizing the dose delivered to the normal tissues around the pituitary gland. METHODS AND MATERIALS: Contours of the pituitary tumor and normal tissues were traced onto computed axial tomography (CT) scans and reconstructed in three dimensions using a three-dimensional planning system. A total dose of 45 Gy was delivered to the pituitary lesion with the five techniques using 6 MV and 18 MV photons, and dose-volume histograms were generated. RESULTS: The 18 MV photons delivered a lower dose to the temporal lobe than did the 6 MV photons in the two-field technique, but this advantage was not evident for the other techniques. The three-field technique improved dose distribution throughout the temporal lobes with low doses being delivered to the frontal lobe. The bilateral arc and the 330 degrees arc techniques were superior to stationary two- and three-fields techniques for sparing the temporal lobes. The four noncoplanar arc technique delivered less doses to the temporal and frontal lobes than did the other techniques. However, the lens dose (3.6 Gy/25 fractions) was higher compared to the other techniques. CONCLUSION: Analysis of the dose-volume histograms shows the various dosimetric advantages and disadvantages of the five techniques. Based upon individual considerations, including the patient's age and medical history, one can decide the optimal technique for treatment.


Assuntos
Neoplasias Hipofisárias , Radioterapia/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Hipofisárias/diagnóstico por imagem , Neoplasias Hipofisárias/radioterapia , Proteção Radiológica , Dosagem Radioterapêutica , Tomografia Computadorizada por Raios X
18.
Int J Radiat Oncol Biol Phys ; 47(4): 1007-12, 2000 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-10863072

RESUMO

PURPOSE: We reviewed our experience with patients who have undergone stereotactic radiosurgery (SRS) for brain metastases secondary to renal cell carcinoma (RCC). Analysis was performed to determine the survival, local control, distant brain failure (DBF), and then to define which tumors may not require upfront whole-brain radiotherapy (WBRT). METHODS AND MATERIALS: Twenty-nine patients with 66 tumors underwent SRS from 1991 to 1998. Median follow-up from time of brain metastases diagnoses relative to each tumor was 12.5 months and 6.8 months from the time of SRS. Median SRS dose was 1,800 cGy to the 60% isodose line. Three patients had undergone SRS for previously treated tumors. RESULTS: Median survival time from diagnosis was 10.0 months. Overall survival was not affected by age, addition of WBRT, number of lesions, tumor volume, or the presence of systemic disease. Of the 23 patients with follow-up neuroimaging, 4 of 47 (9%) tumors recurred. The addition of WBRT did not improve local control. Of the 13 patients who presented with a single lesion, 3 went on to develop DBF (23%), while 6 of the 10 patients who presented with multiple metastases developed DBF (60%). CONCLUSION: Patients with brain metastases secondary to RCC treated by SRS alone have excellent local control. The decision of whether or not to add WBRT to SRS should depend on whether the patient has a high likelihood of developing DBF. Our study suggests that patients who present with multiple brain lesions may be more likely to benefit from the addition of WBRT because they appear to be more than twice as likely to develop DBF as compared to patients with a single lesion.


Assuntos
Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/cirurgia , Carcinoma de Células Renais/radioterapia , Carcinoma de Células Renais/cirurgia , Irradiação Craniana/métodos , Neoplasias Renais/patologia , Radiocirurgia , Adulto , Idoso , Análise de Variância , Encéfalo/patologia , Encéfalo/efeitos da radiação , Neoplasias Encefálicas/secundário , Carcinoma de Células Renais/secundário , Terapia Combinada , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Necrose , Dosagem Radioterapêutica , Análise de Sobrevida , Fatores de Tempo
19.
Int J Radiat Oncol Biol Phys ; 29(1): 187-90, 1994 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-8175429

RESUMO

PURPOSE: A technique is described that uses an independent, asymmetric collimator and a penumbra modifier to uniformly administer radiation over the craniospinal axis. METHOD AND MATERIALS: An isocenter is used at the junction of the cranial and the upper spinal fields. These fields are defined by a single isocenter at spinal cord depth and an independent, asymmetric collimator. From the isocenter, the cranial and upper spinal fields are extended 1 cm inferiorly and superiorly, respectively. A modifier provides a 2-cm wide penumbra at the central axis of the beam (overlapping region) and is attached to a wedge tray in an accessory slot. This modifier allows the fields to be matched so a uniform dose is delivered over the isocenter and junction. Dose distribution was measured with an anthropomorphic head-and-neck wax phantom that included the seventh cervical vertebrae. A film was placed in a coronal cut at the spinal cord level. RESULTS: The administered dose varied less than 10% through the craniospinal axis. Reproducibility with portal films has been very good. Advantages include dose homogeneity, easy reproducibility, and decreased setup time. CONCLUSION: This single-field isocentric technique allows more uniform irradiation of the craniospinal axis than do previously described techniques.


Assuntos
Neoplasias de Cabeça e Pescoço/radioterapia , Radioterapia/instrumentação , Medula Espinal/efeitos da radiação , Humanos
20.
Int J Radiat Oncol Biol Phys ; 47(4): 993-9, 2000 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-10863070

RESUMO

PURPOSE: To evaluate the usefulness of whole brain radiotherapy (WBRT) and of the Radiation Therapy Oncology Group recursive partitioning analysis (RPA) for brain metastases among patients receiving stereotactic radiosurgery (SRS). METHODS AND MATERIALS: A retrospective analysis was performed on 135 patients who underwent linear accelerator (Linac) (n = 73) or Gamma Knife (n = 62) SRS for newly diagnosed brain metastases at the Cleveland Clinic Foundation between 8/89 and 12/98. Univariate and multivariate analyses were performed to evaluate the effects of age, primary site, control of the primary, interval to development of brain metastases (disease-free interval [DFI]), number of brain metastases, presence of extracranial metastases, Karnofsky performance status (KPS), treatment of brain metastases, and RPA class on overall survival. RESULTS: Application of the RPA classification revealed 29 patients fit the criteria for class I, 96 for class II, and 10 for class III. All of the patients underwent SRS. Fifty-seven patients also received WBRT at the time of initial presentation (SRS and immediate WBRT), and 78 patients received WBRT only if CNS relapse occurred (SRS alone). The median survival for all patients was 7.9 months (range: 1.1-90.1), and was 11.2 months for RPA class I compared to 6. 9 months for RPA classes II-III (p = 0.016). Median survival was 10. 5 months following SRS alone compared to 6.4 months following SRS and WBRT (p = 0.07). On univariate analysis, KPS >/= 80% (p = 0.002) and absence of systemic disease (p = 0.013) were also associated with longer survival, whereas control of the primary, DFI, and number of brain metastases did not have an impact. Multivariate analysis revealed only RPA class (p = 0.023) to be an independent predictor for overall survival, whereas treatment group (p = 0.079) was only marginally significant. At 2 years, immediate WBRT improved control at the original site of metastases (80% vs. 52%, p = 0.03) and prevention of new metastatic sites within the brain, 74% vs. 48% (p = 0.06). The 2-year intracranial disease-free survival was 60% following SRS and WBRT compared to only 34% following SRS alone (p = 0.03). CONCLUSIONS: Despite the inherent biases to select more favorable patients for SRS, the RPA class retains its prognostic value. Omission of WBRT from the initial management was not detrimental in terms of overall survival; however, progressive disease occurred in over 50% of patients treated in this manner. Further studies are required to determine which, if any, patients should be considered for SRS with WBRT held in reserve.


Assuntos
Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/cirurgia , Irradiação Craniana/métodos , Radiocirurgia/métodos , Fatores Etários , Idoso , Análise de Variância , Viés , Neoplasias Encefálicas/secundário , Terapia Combinada , Intervalo Livre de Doença , Humanos , Avaliação de Estado de Karnofsky , Pessoa de Meia-Idade , Seleção de Pacientes , Estudos Retrospectivos , Análise de Sobrevida , Fatores de Tempo
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