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1.
Braz. j. biol ; 84: e254646, 2024. tab, ilus
Artículo en Inglés | LILACS, VETINDEX | ID: biblio-1360224

RESUMEN

Chronic stress (CS) can contribute to dysfunction in several organs including liver and kidney. This study was performed to investigate the changes in serum biochemistry, histological structure, as well as in localization of tyrosine phosphorylated proteins (TyrPho) and Heat shock protein 70 (Hsp-70) in liver and kidney tissues of CS rats induced by two stressors (restrained and force swimming) for 60 consecutive days. Samples of blood, liver, and kidney were collected from adult male Sprague-Dawley rats in each group. Our results showed that serum biochemical parameters including corticosterone, blood sugar, urea nitrogen, creatinine, cholesterol, triglyceride, HDL-C, LDL-C, ALT, AST, alkaline phosphatase in CS group were significantly different from that in normal group in both liver and kidney tissues. Although histological structure was not changed. TyrPho expression was significantly increased in liver lysate but significantly decreased in kidney. Hsp-70 expression in liver increased whereas in kidney decreased. In conclusion, CS can induce changes in liver and kidney functions.


O estresse crônico (SC) pode contribuir para a disfunção em vários órgãos, incluindo fígado e rim. Este estudo foi realizado para investigar as alterações na bioquímica sérica, estrutura histológica, bem como na localização de proteínas tirosina fosforiladas (TyrPho) e proteína de choque térmico 70 (Hsp-70) em tecidos hepáticos e renais de ratos CS induzidas por dois estressores (restrito e natação forçada) por 60 dias consecutivos. Amostras de sangue, fígado e rim foram coletadas de ratos Sprague-Dawley machos adultos em cada grupo. Nossos resultados mostraram que os parâmetros bioquímicos séricos, incluindo corticosterona, glicemia, nitrogênio ureico, creatinina, colesterol, triglicerídeos, HDL-C, LDL-C, ALT, AST, fosfatase alcalina no grupo CS foram significativamente diferentes do grupo normal em ambos os fígados e tecidos renais. Embora a estrutura histológica não tenha sido alterada, a expressão de TyrPho aumentou significativamente no lisado hepático, mas diminuiu significativamente no rim. A expressão de Hsp-70 no fígado aumentou, enquanto que no rim diminuiu. Em conclusão, a CS pode induzir alterações nas funções hepáticas e renais.


Asunto(s)
Ratas , Estrés Fisiológico , Ratas Sprague-Dawley , Riñón/anatomía & histología , Hígado/anatomía & histología
2.
Braz. j. biol ; 842024.
Artículo en Inglés | LILACS-Express | LILACS, VETINDEX | ID: biblio-1469354

RESUMEN

Abstract Chronic stress (CS) can contribute to dysfunction in several organs including liver and kidney. This study was performed to investigate the changes in serum biochemistry, histological structure, as well as in localization of tyrosine phosphorylated proteins (TyrPho) and Heat shock protein 70 (Hsp-70) in liver and kidney tissues of CS rats induced by two stressors (restrained and force swimming) for 60 consecutive days. Samples of blood, liver, and kidney were collected from adult male SpragueDawley rats in each group. Our results showed that serum biochemical parameters including corticosterone, blood sugar, urea nitrogen, creatinine, cholesterol, triglyceride, HDL-C, LDL-C, ALT, AST, alkaline phosphatase in CS group were significantly different from that in normal group in both liver and kidney tissues. Although histological structure was not changed. TyrPho expression was significantly increased in liver lysate but significantly decreased in kidney. Hsp-70 expression in liver increased whereas in kidney decreased. In conclusion, CS can induce changes in liver and kidney functions.


Resumo O estresse crônico (SC) pode contribuir para a disfunção em vários órgãos, incluindo fígado e rim. Este estudo foi realizado para investigar as alterações na bioquímica sérica, estrutura histológica, bem como na localização de proteínas tirosina fosforiladas (TyrPho) e proteína de choque térmico 70 (Hsp-70) em tecidos hepáticos e renais de ratos CS induzidas por dois estressores (restrito e natação forçada) por 60 dias consecutivos. Amostras de sangue, fígado e rim foram coletadas de ratos Sprague-Dawley machos adultos em cada grupo. Nossos resultados mostraram que os parâmetros bioquímicos séricos, incluindo corticosterona, glicemia, nitrogênio ureico, creatinina, colesterol, triglicerídeos, HDL-C, LDL-C, ALT, AST, fosfatase alcalina no grupo CS foram significativamente diferentes do grupo normal em ambos os fígados e tecidos renais. Embora a estrutura histológica não tenha sido alterada, a expressão de TyrPho aumentou significativamente no lisado hepático, mas diminuiu significativamente no rim. A expressão de Hsp-70 no fígado aumentou, enquanto que no rim diminuiu. Em conclusão, a CS pode induzir alterações nas funções hepáticas e renais.

3.
Braz J Biol ; 83: e272629, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37436191

RESUMEN

Thai Mucuna pruriens (L.) DC. var pruriens (T-MP) seed containing levodopa (L-DOPA) and antioxidant capacity has been shown to improve sexual behavior and male reproductive parameters in rats treated with ethanol (Eth). However, its protective effect on testicular apoptotic germ cells has never been reported. This study aimed to investigate the potential effects of T-MP seed extract on expressions of caspase, proliferating cell nuclear antigen (PCNA), and dopamine D2 receptor (D2R) proteins in Eth rats. Thirty-six male Wistar rats were divided into four groups (9 animals/group), including control, Eth, T-MP150+Eth, and T-MP300+Eth, respectively. Control rats received distilled water, and Eth rats received Eth (3g/kg BW; 40%v/v). The T-MP groups were treated with T-MP seed extract at a dose of 150 or 300 mg/kg before Eth administration for 56 consecutive days. The results showed that the seminiferous tubule diameter and epithelial height were significantly increased in both T-MP treated groups compared to the Eth group. Additionally, the caspase-9 and -3, and PCNA expressions were decreased, but D2R expression was markedly increased in T-MP groups. It was concluded that T-MP seed extract could protect testicular apoptosis induced by Eth via changes in caspase, PCNA, and D2R protein expressions.


Asunto(s)
Mucuna , Extractos Vegetales , Ratas , Masculino , Animales , Ratas Wistar , Extractos Vegetales/farmacología , Extractos Vegetales/uso terapéutico , Antígeno Nuclear de Célula en Proliferación , Células Germinativas , Caspasas , Etanol
4.
Braz. j. biol ; 83: e272629, 2023. graf, ilus
Artículo en Inglés | VETINDEX | ID: biblio-1447655

RESUMEN

Thai Mucuna pruriens (L.) DC. var pruriens (T-MP) seed containing levodopa (L-DOPA) and antioxidant capacity has been shown to improve sexual behavior and male reproductive parameters in rats treated with ethanol (Eth). However, its protective effect on testicular apoptotic germ cells has never been reported. This study aimed to investigate the potential effects of T-MP seed extract on expressions of caspase, proliferating cell nuclear antigen (PCNA), and dopamine D2 receptor (D2R) proteins in Eth rats. Thirty-six male Wistar rats were divided into four groups (9 animals/group), including control, Eth, T-MP150+Eth, and T-MP300+Eth, respectively. Control rats received distilled water, and Eth rats received Eth (3g/kg BW; 40%v/v). The T-MP groups were treated with T-MP seed extract at a dose of 150 or 300 mg/kg before Eth administration for 56 consecutive days. The results showed that the seminiferous tubule diameter and epithelial height were significantly increased in both T-MP treated groups compared to the Eth group. Additionally, the caspase-9 and -3, and PCNA expressions were decreased, but D2R expression was markedly increased in T-MP groups. It was concluded that T-MP seed extract could protect testicular apoptosis induced by Eth via changes in caspase, PCNA, and D2R protein expressions.


Thai Mucuna pruriens (L.) DC. var pruriens (T-MP) contendo levodopa (L-DOPA) e capacidade antioxidante demonstrou melhorar o comportamento sexual e os parâmetros reprodutivos masculinos em ratos tratados com etanol (Eth). No entanto, seu efeito protetor sobre células germinativas apoptóticas testiculares nunca foi relatado. Este estudo teve como objetivo investigar os efeitos potenciais do extrato de semente de T-MP na expressão de proteínas de caspase, antígeno nuclear de proliferação celular (PCNA) e receptor de dopamina D2 (D2R) em ratos Eth. Trinta e seis ratos Wistar machos foram divididos em quatro grupos (9 animais/grupo), incluindo controle, Eth, T-MP150+Eth e T-MP300+Eth, respectivamente. Ratos controle receberam água destilada e ratos Eth receberam Eth (3g/kg PC; 40%v/v). Os grupos T-MP foram tratados com extrato de semente de T-MP na dose de 150 ou 300 mg/kg antes da administração de Eth por 56 dias consecutivos. Os resultados mostraram que o diâmetro dos túbulos seminíferos e a altura epitelial foram significativamente aumentados em ambos os grupos tratados com T-MP em comparação com o grupo Eth. Além disso, as expressões de caspase-9 e -3 e de PCNA diminuíram, mas a expressão de D2R aumentou acentuadamente nos grupos T-MP. Concluiu-se que o extrato de semente de T-MP pode proteger a apoptose testicular induzida por Eth através de alterações na expressão de proteínas caspase, PCNA e D2R.


Asunto(s)
Animales , Ratas , Testículo , Extractos Vegetales , Apoptosis , Mucuna , Etanol
5.
Braz J Biol ; 84: e254646, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35195171

RESUMEN

Chronic stress (CS) can contribute to dysfunction in several organs including liver and kidney. This study was performed to investigate the changes in serum biochemistry, histological structure, as well as in localization of tyrosine phosphorylated proteins (TyrPho) and Heat shock protein 70 (Hsp-70) in liver and kidney tissues of CS rats induced by two stressors (restrained and force swimming) for 60 consecutive days. Samples of blood, liver, and kidney were collected from adult male Sprague-Dawley rats in each group. Our results showed that serum biochemical parameters including corticosterone, blood sugar, urea nitrogen, creatinine, cholesterol, triglyceride, HDL-C, LDL-C, ALT, AST, alkaline phosphatase in CS group were significantly different from that in normal group in both liver and kidney tissues. Although histological structure was not changed. TyrPho expression was significantly increased in liver lysate but significantly decreased in kidney. Hsp-70 expression in liver increased whereas in kidney decreased. In conclusion, CS can induce changes in liver and kidney functions.


Asunto(s)
Riñón , Hígado , Animales , Riñón/patología , Hígado/patología , Masculino , Fosforilación , Ratas , Ratas Sprague-Dawley , Tirosina
6.
Clin Transl Oncol ; 21(11): 1551-1560, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30945128

RESUMEN

PURPOSE: Neural stem cells (NSCs) have been characterized with the ability of self-renewal and neurogenesis, which has inspired lots of studies to clarify the functions of NSCs in neural injury, ischemic stroke, brain inflammation and neurodegenerative diseases. We focused on the relationship of NSCs with glioblastoma, since we have discovered that recurrent glioblastomas were inclined to be derived from subventricular zone (SVZ), where NSCs reside. We want to clarify whether NSCs are involved in glioblastoma relapse. METHODS: Immunocytochemistry was used to confirm the stemness of NSCs. The Cell Counting Kit-8 was used to measure the proliferation of cells. Migration abilities were examined by wound healing and transwell assays, and tumor formation abilities were confirmed in nude mice. RESULTS: We found in experiments that NSCs promoted proliferation of a glioblastoma cell line-Ln229, the migration ability of Ln229 cells was motivated by co-cultured with NSCs. Tumor formation of Ln229 cells was also accelerated in nude mice when co-transplanted with NSCs. In immunohistochemistry, we found that the Sox2- and Ki67-positive cells were much higher in co-transplanted groups than that of control groups. CONCLUSIONS: These results imply the potential role that NSCs play in speeding up tumor formation in the process of glioblastoma relapse, providing the basis for dealing with newly diagnosed glioblastoma patients, which may help postpone the recurrence of glioblastoma as far as possible through preprocessing the tumor-adjacent SVZ tissue.


Asunto(s)
Movimiento Celular , Proliferación Celular , Glioblastoma/etiología , Células-Madre Neurales/fisiología , Animales , Línea Celular Tumoral , Glioblastoma/química , Antígeno Ki-67/análisis , Ventrículos Laterales , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Células-Madre Neurales/química , Factores de Transcripción SOXB1/análisis , Cicatrización de Heridas
7.
Clin Transl Oncol ; 20(7): 906-911, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29143228

RESUMEN

PURPOSE: Exosomes are gradually detected as an indicator for diagnosis and prognosis of breast cancer in clinic and a systematic review was conducted. METHODS: A search for clinical studies published before July 1, 2017 was performed. Methods of exosome purification and identification from all studies were extracted. For diagnosis evaluation, the comparison of exosome biomarkers expression between breast cancer patients and healthy women was obtained; for prognosis prediction, the correlation between exosome biomarkers expression and chemotherapy resistance, overall survival (OS), disease-free survival (DFS), recurrence and metastasis of breast cancer was also extracted. RESULTS: A total of 11 studies with 921 breast cancer patients were included. Ultracentrifugation is the most frequent method to purify exosomes and transmission electron microscopy is commonly used to identify exosomes. Exosome biomarkers (such as HER2, CD47, Del-1, miR-1246 and miR-21) in breast cancer patients are significantly higher than those in healthy controls, exosomal GSTP1 and TRPC5 are related to chemotherapy resistance, exosome-carrying TRPC5, NANOG, NEUROD1, HTR7, KISS1R and HOXC are correlated to PFS, DFS or OS, and some exosomal proteins (HER2, KDR, CD49d, CXCR4 and CD44) as well as miRNAs (miR-340-5p, miR-17-5p, miR-130a-3p, miR-93-5p) are associated with tumor recurrence or distant organ metastasis. CONCLUSIONS: Exosome biomarkers can be used for early diagnosis and prognosis of breast cancer patients in clinic.


Asunto(s)
Biomarcadores de Tumor/genética , Neoplasias de la Mama/genética , Exosomas/genética , Recurrencia Local de Neoplasia/genética , Biomarcadores de Tumor/sangre , Neoplasias de la Mama/sangre , Neoplasias de la Mama/diagnóstico , Neoplasias de la Mama/terapia , Estudios de Casos y Controles , Terapia Combinada , Femenino , Humanos , Metástasis de la Neoplasia , Recurrencia Local de Neoplasia/sangre , Recurrencia Local de Neoplasia/diagnóstico , Recurrencia Local de Neoplasia/terapia , Pronóstico , Tasa de Supervivencia
8.
Genet Mol Res ; 14(3): 11562-72, 2015 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-26436397

RESUMEN

This study aimed to explore the relationship between genetic changes and high-altitude pulmonary edema (HAPE) susceptibility, and to screen for the key single nucleotide polymorphism (SNP) loci in the HAPE-susceptibility gene, by investigating the SNPs occurring in hypoxia-related genes in HAPE-susceptible and control (non-susceptible) populations. This research was conducted on Han recruits, who travelled to the Lhasa plateau (altitude, 3658 m). Ten loci located on ten genes extracted from the HAPE and healthy populations were amplified by polymerase chain reaction, and subsequently sequenced. The investigated genes included those coding for aldosterone synthase 2 (CYP11B2), angiotensin-converting enzyme (ACE), heat-shock protein 70 (HSP70), nuclear factor kappa B (NF-κB), surfactant protein A2 (SP-A2), plasminogen activator inhibitor-1 (PAI-1), nitric oxide synthetase (NOS), vascular endothelial growth factor (VEGF), prolyl hydroxylase (EGLN1), and zinc finger protein A20. The gene distribution of each SNP loci and its correlation with HAPE was analyzed. Statistical analyses of the genotype frequencies of the SNPs revealed significant differences in the ACE (rs4309), EGLN1 (rs480902), SP-A2 (rs1965708), HSP70 (rs1008438), PAI-1 (rs1799889), and NOS (rs199983) expressions between the HAPE and healthy control groups (P < 0.05); therefore, these SNP loci were believed to indicate HAPE susceptibility. HAPE is correlated with multiple- SNP loci. A correlation analysis between genetic polymorphism and HAPE susceptibility revealed that 6 hypoxia-related genes were key sites accounting for HAPE. These findings could help assess the risk of HAPE in populations expressing different genotypes, in order to reduce the occurrence of HAPE.


Asunto(s)
Altitud , Predisposición Genética a la Enfermedad , Hipoxia/genética , Polimorfismo de Nucleótido Simple/genética , Edema Pulmonar/genética , Enfermedad Aguda , Alelos , Secuencia de Bases , Análisis Mutacional de ADN , Proteínas de Unión al ADN/genética , Frecuencia de los Genes/genética , Sitios Genéticos , Proteínas HSP70 de Choque Térmico/genética , Heterocigoto , Homocigoto , Humanos , Péptidos y Proteínas de Señalización Intracelular/genética , Datos de Secuencia Molecular , FN-kappa B/genética , Óxido Nítrico Sintasa/genética , Proteínas Nucleares/genética , Peptidil-Dipeptidasa A/genética , Inhibidor 1 de Activador Plasminogénico/genética , Prolil Hidroxilasas/genética , Regiones Promotoras Genéticas/genética , Proteína A Asociada a Surfactante Pulmonar/genética , Proteína 3 Inducida por el Factor de Necrosis Tumoral alfa , Factor A de Crecimiento Endotelial Vascular/genética
9.
Genet Mol Res ; 14(2): 5010-21, 2015 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-25966276

RESUMEN

Dihydroflavonol 4-reductase (DFR) genes from Rosa chinensis (Asn type) and Calibrachoa hybrida (Asp type), driven by a CaMV 35S promoter, were integrated into the petunia (Petunia hybrida) cultivar 9702. Exogenous DFR gene expression characteristics were similar to flower-color changes, and effects on anthocyanin concentration were observed in both types of DFR gene transformants. Expression analysis showed that exogenous DFR genes were expressed in all of the tissues, but the expression levels were significantly different. However, both of them exhibited a high expression level in petals that were starting to open. The introgression of DFR genes may significantly change DFR enzyme activity. Anthocyanin ultra-performance liquid chromatography results showed that anthocyanin concentrations changed according to DFR enzyme activity. Therefore, the change in flower color was probably the result of a DFR enzyme change. Pelargonidin 3-O-glucoside was found in two different transgenic petunias, indicating that both CaDFR and RoDFR could catalyze dihydrokaempferol. Our results also suggest that transgenic petunias with DFR gene of Asp type could biosynthesize pelargonidin 3-O-glucoside.


Asunto(s)
Oxidorreductasas de Alcohol/biosíntesis , Flores/genética , Regulación de la Expresión Génica de las Plantas , Petunia/genética , Proteínas de Plantas/biosíntesis , Plantas Modificadas Genéticamente , Oxidorreductasas de Alcohol/genética , Antocianinas/biosíntesis , Color , Flavonoides/metabolismo , Flores/anatomía & histología , Flores/enzimología , Petunia/anatomía & histología , Petunia/enzimología , Proteínas de Plantas/genética , Regiones Promotoras Genéticas , Rosa/química , Rosa/enzimología , Solanaceae/química , Solanaceae/enzimología , Transgenes
10.
Genet Mol Res ; 13(4): 10952-7, 2014 Dec 19.
Artículo en Inglés | MEDLINE | ID: mdl-25526216

RESUMEN

Gastric cancer is the fourth most common cancer worldwide and the leading cause of tumor-related death in China. Gastric cancer is a heterogeneous disease and therefore requires different treatments based on the subtype. We describe a patient who had gastric cancer with liver metastases. Biopsy and tumor analysis using the HercepTest revealed a human epidermal growth factor receptor 2 (HER2)-positive adenocarcinoma as confirmed by fluorescence in situ hybridization. The patient was treated with a regimen of trastuzumab, oxaliplatin, and S-1 (six cycles). When positron emission tomography findings suggested that the metastases had resolved, the patient underwent surgery. Histopathologically, no cancer cells were observed in the resected hepatic tissue. The patient underwent tumor resection surgery, during which the tumor and gastric lymph nodes with lesions were removed. The patient has remained disease-free for 3 months. Therefore, trastuzumab may be an effective agent in the chemotherapeutic treatment of liver metastases in patients with HER2-positive gastric adenocarcinoma.


Asunto(s)
Anticuerpos Monoclonales Humanizados/administración & dosificación , Antineoplásicos/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias Hepáticas/secundario , Neoplasias Gástricas/tratamiento farmacológico , Neoplasias Gástricas/cirugía , Combinación de Medicamentos , Femenino , Humanos , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/cirugía , Persona de Mediana Edad , Compuestos Organoplatinos/administración & dosificación , Oxaliplatino , Ácido Oxónico/administración & dosificación , Receptor ErbB-2/genética , Neoplasias Gástricas/genética , Neoplasias Gástricas/patología , Tegafur/administración & dosificación , Trastuzumab , Resultado del Tratamiento
12.
J Pediatr ; 138(1): 59-64, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11148513

RESUMEN

OBJECTIVE: To evaluate the consistency of pediatric asthma care with the National Asthma Education and Prevention Program Guidelines. DESIGN: Cross-sectional survey at 2 managed care organizations in the United States (winter 1997-1998). The participants were parents of children (n = 318) age 5 to 17 years with asthma. There were no interventions. The outcome measures were indicators of care in 4 domains: (1) periodic physiologic assessment, (2) proper use of medications, (3) patient education, and (4) control of factors contributing to asthma severity. RESULTS: Of 533 eligible patients with asthma, 318 (60%) parents responded; 59% of children were male, 76% were white, and 60% were aged 5 to 10 years. Deficiencies in care were identified in all care domains including, for patients with moderate and severe persistent symptoms, only 55% used long-term control medication daily, 49% had written instructions for handling asthma attacks, 44% had instructions for adjustment of medication before exposures, 56% had undergone allergy testing, and 54% had undergone pulmonary function testing. CONCLUSIONS: There are significant opportunities to improve the quality of care for children with asthma enrolled in managed care. A comprehensive approach to improving care may be necessary to address multiple aspects of care where opportunities exist.


Asunto(s)
Asma/terapia , Adhesión a Directriz/normas , Programas Controlados de Atención en Salud/normas , Pediatría/normas , Guías de Práctica Clínica como Asunto , Calidad de la Atención de Salud , Adolescente , Asma/diagnóstico , Asma/etiología , Actitud Frente a la Salud , Niño , Preescolar , Estudios Transversales , Femenino , Adhesión a Directriz/estadística & datos numéricos , Investigación sobre Servicios de Salud , Humanos , Masculino , Programas Controlados de Atención en Salud/estadística & datos numéricos , Medio Oeste de Estados Unidos , Evaluación de Necesidades/organización & administración , New England , Evaluación de Resultado en la Atención de Salud , Padres/educación , Padres/psicología , Educación del Paciente como Asunto/normas , Pediatría/métodos , Pediatría/estadística & datos numéricos , Indicadores de Calidad de la Atención de Salud , Índice de Severidad de la Enfermedad , Encuestas y Cuestionarios , Gestión de la Calidad Total/organización & administración
13.
Int J Radiat Oncol Biol Phys ; 25(3): 551-6, 1993 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-8436534

RESUMEN

The substitution of Ir-192 seed ribbons for wires in the Paris system of interstitial implants was re-evaluated using the dose nonuniformity ratio. The dose nonuniformity ratio, which is based on volumetric data, measures the dose nonuniformity of the implant quantitatively. The lower the dose nonuniformity ratio value, the smaller the dose nonuniformity, and the better is the dose homogeneity for the implant. Implants configured in a single-plane and double-planes in the form of squares or triangles using Ir-192 wires or seed ribbons were considered. The difference between the particular reference dose rate that yielded a minimum in the dose nonuniformity ratio curve for wire implants and seed implants is about 4 cGy/hr. The difference between the minimum dose nonuniformity ratio value representing the optimal dose homogeneity of the implants is about 5%. The dose homogeneity may be considered better for implants configured using seed ribbons.


Asunto(s)
Braquiterapia/instrumentación , Radioisótopos de Iridio/uso terapéutico , Estudios de Evaluación como Asunto , Humanos , Radioisótopos de Iridio/administración & dosificación , Dosificación Radioterapéutica
14.
Med Dosim ; 17(1): 35-6, 1992 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-1558645

RESUMEN

The percent depth dose of 8 MV and 18 MV photon beams were measured for various field sizes. The percent depth dose curves exhibited crossed over at selective depth in phantom. Hence, the percent depth dose increases at shallower depth, is independent at crossed over depth, and decreases at deeper depth with decreasing field size. This peculiar phenomenon, which cannot be explained using the primary and scattered radiation concept, should be noted.


Asunto(s)
Dosificación Radioterapéutica , Radioterapia de Alta Energía , Humanos , Modelos Estructurales
15.
Med Dosim ; 17(3): 145-50, 1992.
Artículo en Inglés | MEDLINE | ID: mdl-1388680

RESUMEN

The isodose distributions are related to the source configurations in the Paris system of interstitial implants. In this system, the basal dose rates are determined at those points identified relative to the implant. Once these points have been located, the basal dose rates are merely the summation of the dose rate contributions from all the sources. By applying the symmetry properties of the implant, the number of basal dose rate computations and the number of dose rate summations are reduced. The reduction in both the number of computations and the number of summations has facilitated the determination of the average basal dose rate. After the average basal dose rate has been determined, the reference dose rate that is used clinically is calculated. Examples of determining the basal dose rates for a few interstitial implants are presented.


Asunto(s)
Braquiterapia , Radioisótopos de Iridio/uso terapéutico , Humanos , Radiometría , Dosificación Radioterapéutica
16.
Med Dosim ; 17(4): 181-5, 1992.
Artículo en Inglés | MEDLINE | ID: mdl-1485904

RESUMEN

Various wedge isodose angles or simply wedge angles smaller than the nominal wedge angle were created by combining the isodose distributions generated from a single physical wedge with the isodose distributions of the open field for the 8-MV photon beam. The particular wedge angle generated depends on the weights imposed on these isodose distributions. The relationship between these weights and the wedge angle were examined and found to be nonlinear. The difference between the wedge angles defined at 10 cm depth and those defined using the 50% isodose curve is less 6 degrees. The present data was fitted using two proposed empirical equations.


Asunto(s)
Dosificación Radioterapéutica , Radioterapia Asistida por Computador , Humanos , Aceleradores de Partículas
17.
Med Dosim ; 17(4): 187-90, 1992.
Artículo en Inglés | MEDLINE | ID: mdl-1485905

RESUMEN

The open-field and wedged-field output factors as a function of field size for two linear accelerators were measured. Wedge factors were determined by taking the ratio of the outputs with and without the wedge filter. For one linear accelerator, the difference in the output factors between the wedged field and open field can be as large as 5%. The wedge factor for this linear accelerator also varies with the field size. On the other hand, the other linear accelerator shows smaller variation of output factors between wedge field and open field. The variation of wedge factor is less than 1% for a 60 degree wedge. In addition to modifying the isodose distributions, the wedge filter also changes the percent depth dose curves, the output factor, and the wedge factor. The degree of wedge effects on these dosimetric parameters is different for different linear accelerator.


Asunto(s)
Aceleradores de Partículas , Dosificación Radioterapéutica , Filtración
18.
Int J Radiat Oncol Biol Phys ; 23(1): 19-26, 1992.
Artículo en Inglés | MEDLINE | ID: mdl-1572817

RESUMEN

In order to analyze complications and the factors responsible for the development of serial imaging changes after stereotactic radiosurgery for intracranial arteriovenous malformations, we reviewed serial post-treatment magnetic resonance imaging scans in 72 patients. Median follow-up was 23 months (range 12 to 35 months). Twenty patients developed post-radiosurgical imaging changes consisting of new regions of increased T2 signal on magnetic resonance imaging in brain surrounding the arteriovenous malformation (two year actuarial incidence of 31%). Imaging changes were associated with headache or new neurological deficits in nine of these 20 (45%) and remained asymptomatic in 11 (55%). Symptoms developed in three of 13 patients with imaging changes in the cerebral cortex or cerebellum, in contrast to six of seven patients who had symptoms with imaging changes in the brainstem (p = .028). The onset of imaging changes varied from five to 18 months after radiosurgery (median, 12 months). Serial follow-up scans four to 25 months after the onset of imaging changes were available for review in 16 patients. Post-radiosurgical imaging changes completely resolved within 4 to 19 months in ten patients and have not yet completely resolved after 6 to 25 months in six patients. The projected actuarial rate for resolution of imaging changes was 88%, 19 months after onset; the median time for resolution was 14 months. Univariate analysis revealed that the development of imaging changes was significantly associated with treatment volume (p = .025), the risk predicted from the integrated logistic formula (p = .042), and the number of isocenters treated (p = .042). In multivariate analysis, volume was the only factor significantly associated with the development of imaging changes.


Asunto(s)
Encéfalo/efectos de la radiación , Malformaciones Arteriovenosas Intracraneales/cirugía , Complicaciones Posoperatorias/epidemiología , Radiocirugia/efectos adversos , Adolescente , Adulto , Anciano , Encéfalo/patología , Niño , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Malformaciones Arteriovenosas Intracraneales/epidemiología , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad
19.
Int J Radiat Oncol Biol Phys ; 19(3): 783-9, 1990 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-2120161

RESUMEN

The Leksell gamma unit at the University of Pittsburgh uses 201 highly focused 60Co beams arranged in a hemispherical array. Selective beam blocking can be used to modify the treatment volume into ellipsoid shapes oriented in different directions to match better the shape of the target volume. Dose distributions for different blocking patterns were calculated using specially developed computerized 3-D treatment planning software. The changes in dose distribution with different blocking patterns predicted by computer were verified by film densitometry. Techniques for using selective beam blocking to match more closely the treatment volume to the intended target volume have the potential of reducing the likelihood of complications for radiosurgery with the Leksell gamma unit and need to be further developed.


Asunto(s)
Neoplasias Encefálicas/radioterapia , Radioisótopos de Cobalto/uso terapéutico , Malformaciones Arteriovenosas Intracraneales/radioterapia , Planificación de la Radioterapia Asistida por Computador , Humanos , Radioterapia de Alta Energía/instrumentación , Radioterapia de Alta Energía/métodos , Técnicas Estereotáxicas
20.
Int J Radiat Oncol Biol Phys ; 18(4): 941-9, 1990 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-2182583

RESUMEN

The Presbyterian-University Hospital of Pittsburgh installed the first clinically designated Leksell gamma knife in the U.S. in August 1987. Gamma knife radiosurgery involves stereotactic target localization with the Leksell frame and subsequent closed-skull single-treatment session irradiation of a lesion with multiple highly focused gamma ray beams produced from 60Co sources. The hemispherical array of sources, the large number of small-diameter beams, and the steep dose gradients surrounding a targeted lesion make physical characterization of the radiation field complex. This paper describes the physical features and the operation of the gamma knife as well as the calibration procedures of the very small, well-collimated beams. The results of studies using in-phantom ion chamber, diode, film, and lithium fluoride thermoluminescent dosimetry were all in close agreement. Both single-beam and multiple-beam dose profiles were measured and reported for the interchangeable helmets, which have 4-, 8-, 14-, and 18-mm-diameter collimators. We also describe the dose calculation and treatment planning algorithm in the treatment planning system. Measurements of the accuracy of mechanical and radiation alignment are also performed and discussed.


Asunto(s)
Encefalopatías/radioterapia , Radioisótopos de Cobalto/uso terapéutico , Radioterapia/instrumentación , Técnicas Estereotáxicas/instrumentación , Humanos
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