Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 43
Filtrar
1.
Sensors (Basel) ; 24(1)2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38203130

RESUMO

Telemedicine has the potential to improve access and delivery of healthcare to diverse and aging populations. Recent advances in technology allow for remote monitoring of physiological measures such as heart rate, oxygen saturation, blood glucose, and blood pressure. However, the ability to accurately detect falls and monitor physical activity remotely without invading privacy or remembering to wear a costly device remains an ongoing concern. Our proposed system utilizes a millimeter-wave (mmwave) radar sensor (IWR6843ISK-ODS) connected to an NVIDIA Jetson Nano board for continuous monitoring of human activity. We developed a PointNet neural network for real-time human activity monitoring that can provide activity data reports, tracking maps, and fall alerts. Using radar helps to safeguard patients' privacy by abstaining from recording camera images. We evaluated our system for real-time operation and achieved an inference accuracy of 99.5% when recognizing five types of activities: standing, walking, sitting, lying, and falling. Our system would facilitate the ability to detect falls and monitor physical activity in home and institutional settings to improve telemedicine by providing objective data for more timely and targeted interventions. This work demonstrates the potential of artificial intelligence algorithms and mmwave sensors for HAR.


Assuntos
Inteligência Artificial , Telemedicina , Humanos , Atividades Humanas , Inteligência , Exercício Físico
2.
Sensors (Basel) ; 23(18)2023 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-37765729

RESUMO

We describe a study on the effect of temperature variations on multi-channel time-to-digital converters (TDCs). The objective is to study the impact of ambient thermal variations on the performance of field-programmable gate array (FPGA)-based tapped delay line (TDL) TDC systems while simultaneously meeting the requirements of high-precision time measurement, low-cost implementation, small size, and low power consumption. For our study, we chose two devices, Artix-7 and ProASIC3L, manufactured by Xilinx and Microsemi, respectively. The radiation-tolerant ProASIC3L device offers better stability in terms of thermal sensitivity and power consumption compared to the Artix-7. To assess the performance of the TDCs under varying thermal conditions, a laboratory thermal chamber was utilized to maintain ambient temperatures ranging from -75 to 80 °C. This analysis ensured a comprehensive evaluation of the TDCs' performance across a wide operational range. By utilizing the Artix-7 and ProASIC3L devices, we achieved root mean square (RMS) resolution of 24.7 and 554.59 picoseconds, respectively. Total on-chip power of 0.968 W was achieved using Artix-7, while 1.997 mW of power consumption was achieved using the ProASIC3L device. We worked to determine the temperature sensitivity for both FPGA devices, which could help in the design and optimization of FPGA-based TDCs for many applications.

3.
Sensors (Basel) ; 23(14)2023 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-37514914

RESUMO

We present a Tapped Delay Line (TDL)-based Time to Digital Converter (TDC) using Wave Union type A (WU-A) architecture for applications that require high-precision time interval measurements with low size, weight, power, and cost (SWaP-C) requirements. The proposed TDC is implemented on a low-cost Field-Programmable Gate Array (FPGA), Artix-7, from Xilinx. Compared to prior works, our high-precision multi-channel TDC has the lowest SWaP-C requirements. We demonstrate an average time precision of less than 3 ps and a Root Mean Square resolution of about 1.81 ps. We propose a novel Wave Union type A architecture where only the first multiplexer is used to generate the wave union pulse train at the arrival of the start signal to minimize the required computational processing. In addition, an auto-calibration algorithm is proposed to help improve the TDC performance by improving the TDC Differential Non-Linearity and Integral Non-Linearity.

4.
Ann Thorac Med ; 9(4): 209-15, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25276239

RESUMO

AIMS: The main objective of this study is to describe patients' clinical characteristics and physiological and hemodynamic parameters at the time of diagnosis in a pulmonary hypertension center in Saudi Arabia. MATERIALS AND METHODS: This study reports the results from a single pulmonary hypertension specialized center in Riyadh, Saudi Arabia, namely Prince Sultan Medical Military City/Cardiac Center (PSMMC & CC). Both newly diagnosed (incidence) and referred (prevalence) cases of pulmonary arterial hypertension are included. All characteristics, including clinical, physiological, and hemodynamic parameters at the time of diagnosis are described. RESULTS: A total of 107 patients were identified as having pulmonary arterial hypertension as diagnosed by right heart catheterization. The mean age at diagnosis was 36 (± 9) years, and there was a female preponderance of 62.6%. The mean duration between symptom onset and diagnosis was 27.8 (± 9.0) months. At the time of enrollment, 56.1% of patients were in functional class III and 16.8% were in functional class IV. Fifty five patients (51.4%) were diagnosed as idiopathic pulmonary arterial hypertension, 29 patients (27.1%) as congenital heart disease associated with pulmonary arterial hypertension, 16 patients (15.0%) as connective tissue diseases associated with pulmonary arterial hypertension, 4 patients (3.7%) as heritable pulmonary arterial hypertension, and 3 patients (2.8%) as portopulmonary hypertension. CONCLUSION: This data highlights the current situation of pulmonary arterial hypertension in Saudi Arabia. Our patients are much younger than patients described in other international registries but still detected as late in the course of the disease. A majority of patients displays severe functional and hemodynamic compromise.

5.
Eur J Neurol ; 20(5): 831-5, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23305332

RESUMO

BACKGROUND AND PURPOSE: Patients with symptomatic carotid stenosis (sCS) have a higher risk of stroke recurrence following the first ischaemic event. Guidelines recommend that patients undergo carotid revascularization (CR), preferably within 2 weeks of the event. We aimed to determine the rate of stroke recurrence during hospitalization in patients who were admitted to the hospital with an acute ischaemic event and who underwent CR for recently sCS. METHODS: As part of the stroke registry in Schleswig-Holstein, Germany (QugSS2; Qualitätsgemeinschaft Schlaganfallversorgung in Schleswig-Holstein), over a 4.5-year period (starting 2007) all patients (N = 15,797) who were admitted to the hospital with an acute cerebral ischaemic event were included and prospectively evaluated. RESULTS: A total of 597 (3.8%) patients (mean age, 71 ± 10 years; 30% women) underwent a CR. The median time between symptom onset and admission to hospitals was 6 h. During the mean hospitalization of 10 days, 30 patients (5%) suffered a stroke. The rates of stroke recurrence were higher, albeit non-significantly, in men compared with women (6% vs. 2.3%, respectively; P = 0.059), and in patients admitted with ischaemic stroke compared with patients admitted with transient ischaemic attack (6.1% vs. 2%, respectively; P = 0.052). The risk of stroke recurrence did not show any association with the other demographic and clinical parameters. CONCLUSION: The rate of stroke recurrence was 5% in patients with recently sCS who scheduled for CR. This suggests that CR should be performed immediately after presenting event to prevent stroke recurrence.


Assuntos
Artéria Carótida Interna , Estenose das Carótidas/complicações , Estenose das Carótidas/cirurgia , Endarterectomia das Carótidas/efeitos adversos , Ataque Isquêmico Transitório/complicações , Acidente Vascular Cerebral/complicações , Idoso , Isquemia Encefálica/complicações , Estenose das Carótidas/diagnóstico , Avaliação da Deficiência , Feminino , Humanos , Tempo de Internação , Masculino , Estudos Prospectivos , Recidiva , Sistema de Registros , Fatores de Risco
6.
Br J Cancer ; 86(4): 517-23, 2002 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-11870530

RESUMO

Based on the assumption that an accelerated proliferation process prevails in tumour cell residues after surgery, the possibility that treatment acceleration would offer a therapeutic advantage in postoperative radiotherapy of locally advanced head and neck cancer was investigated. The value of T(pot) in predicting the treatment outcome and in selecting patients for accelerated fractionation was tested. Seventy patients with (T2/N1-N2) or (T3-4/any N) squamous cell carcinoma of the oral cavity, larynx and hypopharynx who underwent radical surgery, were randomized to either (a) accelerated hyperfractionation: 46.2 Gy per 12 days, 1.4 Gy per fraction, three fractions per day with 6 h interfraction interval, treating 6 days per week or (b) Conventional fractionation: 60 Gy per 6 weeks, 2 Gy per fraction, treating 5 days per week. The 3-year locoregional control rate was significantly better in the accelerated hyperfractionation (88 +/- 4%) than in the CF (57+/- 9%) group, P=0.01 (and this was confirmed by multivariate analysis), but the difference in survival (60 +/- 10% vs 46 +/- 9%) was not significant (P=0.29). The favourable influence of a short treatment time was further substantiated by demonstrating the importance of the gap between surgery and radiotherapy and the overall treatment time between surgery and end of radiotherapy. Early mucositis progressed more rapidly and was more severe in the accelerated hyperfractionation group; reflecting a faster rate of dose accumulation. Xerostomia was experienced by all patients with a tendency to be more severe after accelerated hyperfractionation. Fibrosis and oedema also tended to be more frequent after accelerated hyperfractionation and probably represent consequential reactions. T(pot) showed a correlation with disease-free survival in a univariate analysis but did not prove to be an independent factor. Moreover, the use of the minimum and corrected P-values did not identify a significant cut-off. Compared to conventional fractionation, accelerated hyperfractionation did not seem to offer a survival advantage in fast tumours though a better local control rate was noted. This limits the use of T(pot) as a guide for selecting patients for accelerated hyperfractionation. For slowly growing tumours, tumour control and survival probabilities were not significantly different in the conventional fractionation and accelerated hyperfractionation groups. A rapid tumour growth was associated with a higher risk of distant metastases (P=0.01). In conclusion, tumour cell repopulation seems to be an important determinant of postoperative radiotherapy of locally advanced head and neck cancer despite lack of a definite association between T(pot) and treatment outcome. In fast growing tumours accelerated hyperfractionation provided an improved local control but without a survival advantage. To gain a full benefit from treatment acceleration, the surgery-radiotherapy gap and the overall treatment time should not exceed 6 and 10 weeks respectively.


Assuntos
Carcinoma de Células Escamosas/radioterapia , Neoplasias de Cabeça e Pescoço/radioterapia , Adulto , Idoso , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/cirurgia , Terapia Combinada , Intervalo Livre de Doença , Fracionamento da Dose de Radiação , Feminino , Fibrose/etiologia , Neoplasias de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/cirurgia , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Cuidados Pós-Operatórios , Lesões por Radiação/etiologia , Dosagem Radioterapêutica , Xerostomia/etiologia
7.
Br J Cancer ; 83(1): 30-4, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10883664

RESUMO

Cyclin A expression was studied in a series of 65 squamous cell carcinomas of the head and neck (HNSCC) and compared with known markers of proliferation, iododeoxyuridine (IdUrd) and Ki-67, to assess whether aberrant expression was prevalent. Patients had previously been administered IdUrd to study cell kinetics in relation to outcome of radiotherapy. The data showed that all three parameters were highly correlated although the absolute values were different. The median labelling indices (LI) for IdUrd, cyclin A and Ki-67 were 10.7, 17.1 and 30.8% respectively, reflecting the known pattern of differential cell cycle expression. However, there were a significant number of cases in which an unexpected relationship between cyclin A and either IdUrd or Ki-67 was present. Some of these were attributable to overexpression but others indicated underexpression. Although the greater variability and range of cyclin A expression, coupled with its more closely associated role in cell cycle regulation, might suggest that it may be a more informative marker for cell proliferation than Ki-67, the aberrant expression seen in over one third of cases would indicate that caution should be exercised in interpreting cyclin A as a surrogate marker of proliferation in HNSCC.


Assuntos
Carcinoma de Células Escamosas/metabolismo , Ciclina A/biossíntese , Regulação Neoplásica da Expressão Gênica , Neoplasias de Cabeça e Pescoço/metabolismo , Proteínas de Neoplasias/biossíntese , Adulto , Idoso , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/radioterapia , Carcinoma de Células Escamosas/cirurgia , Ciclo Celular/efeitos da radiação , Terapia Combinada , Ciclina A/genética , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos da radiação , Neoplasias de Cabeça e Pescoço/genética , Neoplasias de Cabeça e Pescoço/radioterapia , Neoplasias de Cabeça e Pescoço/cirurgia , Humanos , Idoxuridina/farmacocinética , Antígeno Ki-67/análise , Masculino , Pessoa de Meia-Idade , Terapia Neoadjuvante , Proteínas de Neoplasias/análise , Proteínas de Neoplasias/genética , Cuidados Pós-Operatórios , Estudos Prospectivos , Teleterapia por Radioisótopo , Radioterapia Adjuvante
8.
Radiother Oncol ; 50(1): 13-23, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10225552

RESUMO

PURPOSE: The aim of this study was to assess the potential of pre-treatment cell kinetic parameters to predict outcome in head and neck cancer patients treated by conventional radiotherapy. MATERIALS AND METHODS: Data from 11 different centers were pooled. Inclusion criteria were such that the patients received radiotherapy alone, and that the radiotherapy was given in an overall time of at least 6 weeks with a dose of at least 60 Gy. All patients received a tracer dose of either iododeoxyuridine (IdUrd) or bromodeoxyuridine (BrdUrd) intravenously prior to treatment and a tumor biopsy was taken several hours later. The cell kinetic parameters labeling index (LI), DNA synthesis time (Ts) and potential doubling time (Tpot) were subsequently calculated from flow cytometry data, obtained on the biopsies using antibodies against I/BrdUrd incorporated into DNA. Each center carried out their own flow cytometry analysis. RESULTS: From the 11 centers, a total of 476 patients conforming to the inclusion criteria were analyzed. Median values for overall time and total dose were 49 days and 69 Gy, respectively. Fifty one percent of patients had local recurrences and 53% patients had died, the majority from their disease. Median follow-up was 20 months; being 30 months for surviving patients. Multivariate analysis revealed that T-stage, maximum tumor diameter, differentiation grade, N-stage, tumor localization and overall time correlated with locoregional control, in decreasing order of significance. For the cell kinetic parameters, univariate analysis showed that only LI was significantly associated with local control (P=0.02), with higher values correlating with a worse outcome. Ts showed some evidence that patients with longer values did worse, but this was not significant (P=0.06). Tpot showed no trend (P=0.8). When assessing survival in a univariate analysis, neither LI nor Tpot associated with outcome (P=0.4, 0.4, respectively). Surprisingly, Ts did correlate with survival, with longer values being worse (P=0.02). In the multivariate analysis of local control, LI lost its significance (P=0.16). CONCLUSIONS: The only pretreatment kinetic parameter for which some evidence was found for an association with local control (the best end-point for testing the present hypothesis) was LI, not Tpot, and this evidence disappeared in a multivariate analysis. It therefore appears that pretreatment cell kinetic measurements carried out using flow cytometry, only provide a relatively weak predictor of outcome after radiotherapy in head and neck cancer.


Assuntos
Neoplasias de Cabeça e Pescoço/patologia , Análise de Variância , Antimetabólitos , Bromodesoxiuridina , Ciclo Celular , Divisão Celular/efeitos da radiação , DNA/biossíntese , DNA/efeitos da radiação , Feminino , Citometria de Fluxo , Seguimentos , Previsões , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Idoxuridina , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Recidiva Local de Neoplasia/patologia , Estadiamento de Neoplasias , Dosagem Radioterapêutica , Taxa de Sobrevida , Resultado do Tratamento
9.
Radiother Oncol ; 25(4): 261-6, 1992 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1480771

RESUMO

Fifty-six patients with locally advanced head and neck squamous cell carcinoma were subjected to adjuvant radiotherapy after radical surgery with randomisation to either conventional fractionation (CF), comprising 50 Gy/25 F/5 weeks, or to accelerated hyperfractionation (AHF) to a dose of 42 Gy/30 F/11 days (3 F/day), a dose/F of 1.4 Gy and an interfraction interval of 4 h. The in vitro [3H]thymidine labelling index (TLI) was determined as an indicator of tumour proliferation. Early mucosal reactions were somewhat more severe after AHF than after CF and the peak was attained earlier. The actuarial 3-year complication rate was significantly lower in the AHF (64%) than in the CF group (87%). This is probably related to a smaller fraction size and a lower total dose. The overall 3-year disease-free survival amounted to 46 +/- 7%. Sex, the anatomical site, the nodal status, the performance status and TLI have been shown to be significant prognostic factors, but only the latter two proved to be independent covariates. Overall, the type of fractionation did not seem to influence survival. However, AHF seemed to offer higher survival probabilities in fast growing tumours and this attained a significant level for tumours with TLI > 10.4% (Tpot < 4.5 days). However, CF and AHF were associated with similar survival rates in slowly growing tumours. The relative effectiveness of the CF and AHF schedules is predictable on the basis of the linear-quadratic system. In the case of tumour response, a time factor has to be included assuming that accelerated repopulation of microscopic residues occurs from the outset.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/radioterapia , Neoplasias de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/radioterapia , Cuidados Pós-Operatórios , Dosagem Radioterapêutica , Adulto , Idoso , Divisão Celular/efeitos da radiação , Terapia Combinada , Feminino , Humanos , Neoplasias Laríngeas/patologia , Neoplasias Laríngeas/radioterapia , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Neoplasias Bucais/patologia , Neoplasias Bucais/radioterapia , Recidiva Local de Neoplasia , Neoplasias Faríngeas/patologia , Neoplasias Faríngeas/radioterapia , Pele/efeitos da radiação , Análise de Sobrevida , Timidina , Trítio
10.
Int J Radiat Oncol Biol Phys ; 23(3): 511-7, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1612951

RESUMO

Two hundred thirty-six patients with T3 bladder cancer who survived radical surgery and proved to have P3a, P3b, or P4a tumors were randomized in two phases into three groups: (a) no further treatment (83 patients); (b) postoperative radiotherapy multiple daily fractionation (MDF), using 3 daily fractions of 1.25 Gy each, with 3 hr between fractions, up to a total dose of 37.5 Gy in 12 days (75 patients); and (c) postoperative radiotherapy conventional fractionation (CF), for a total dose of 50 Gy/5 weeks (78 patients). The tolerance of the patients to postoperative radiotherapy was quite acceptable, with equal acute reactions in MDF and CF groups. The 5-year disease-free survival (DFS) rates amounted to 49 and 44% in MDF and CF postoperative radiotherapy groups, respectively, compared to 25% in the cystectomy-alone group. The 5-year local control rates were 87% and 93% for those treated with multiple daily fractionation and conventional fractionation while it was 50% in the surgery-alone group. The therapeutic benefit of postoperative irradiation was consistent for all tumor types, histological grades, and pathological stages for both the disease-free survival and local control. Patients with nodal metastases demonstrated lower recurrence rates in the postoperative radiotherapy groups, but this was not associated with improved disease-free survival. Multivariate analysis using the Cox Model confirmed these results. The independent prognostic factors affecting both disease-free survival and local control were the addition of postoperative radiotherapy, the nodal status, the pathological stage, and the tumor grade. Late complications of radiotherapy in the skin, small intestine, rectum, and the anastomotic site of the urinary division were lower with MDF than with conventional fractionation.


Assuntos
Esquistossomose/terapia , Doenças da Bexiga Urinária/terapia , Neoplasias da Bexiga Urinária/radioterapia , Adulto , Terapia Combinada , Cistectomia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Radioterapia/efeitos adversos , Dosagem Radioterapêutica , Distribuição Aleatória , Neoplasias da Bexiga Urinária/mortalidade
11.
Int J Radiat Oncol Biol Phys ; 19(5): 1229-32, 1990 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-2254118

RESUMO

Lung and hepatic toxicities constituted the main radiation-related damage after half-body irradiation (HBI) used as the treatment for patients with non-Hodgkin's lymphomas (NHL). Liver damage was mostly transient after a single dose of 8 Gy and could be well monitored by serum enzyme levels. A dose-response relationship could be shown for lung damage in the single dose range of 6.25-9.25 Gy, but the relationship did not reach statistical significance. A significant dose-rate effect could be shown. Mediastinal involvement by lymphoma seemed to increase the risk of pneumonitis. In a radical setting half-body irradiation is recommended to be used at a low dose-rate or as a multifraction irradiation in order to reduce the risk of liver and lung toxicities.


Assuntos
Linfoma não Hodgkin/radioterapia , Irradiação Corporal Total/efeitos adversos , Adulto , Relação Dose-Resposta à Radiação , Feminino , Humanos , Fígado/efeitos da radiação , Pulmão/efeitos da radiação , Masculino , Pessoa de Meia-Idade , Pneumonia/etiologia
12.
Int J Radiat Oncol Biol Phys ; 16(4): 1083-4, 1989 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-2522918

RESUMO

Following an IV infusion of 2.0 g/m2 of Etanidazole, the mean tumor concentration 40 min after injection was 126 micrograms/g in bladder cancer and 65 micrograms/g in cervical cancer. The tumor/plasma concentration ratio was 1.88 in bladder and 0.85 in cervical cancer. This high tumor concentration in bladder cancer could be accounted for by diffusion from a highly concentrated urine. This renders bladder cancer a suitable clinical model for testing this sensitizer.


Assuntos
Carcinoma de Células Escamosas/metabolismo , Nitroimidazóis/farmacocinética , Radiossensibilizantes/farmacocinética , Neoplasias da Bexiga Urinária/metabolismo , Neoplasias do Colo do Útero/metabolismo , Carcinoma de Células Escamosas/urina , Difusão , Etanidazol , Feminino , Humanos , Nitroimidazóis/urina , Radiossensibilizantes/urina , Neoplasias da Bexiga Urinária/urina , Neoplasias do Colo do Útero/urina
13.
Radiother Oncol ; 11(4): 327-36, 1988 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-3375459

RESUMO

The first step in the execution of an interstitial implant is the decision on size and location of the target volume. Several implant systems, e.g. the Paterson-Parker system and the Paris system, give instructions for the optimal arrangement of sources to assure that the planned target volume is adequately covered. They also give guidelines to calculate the reference dose rate encompassing the planned target volume. These systems provide different solutions for the source arrangement for the same planned target volume, and vice versa, resulting in different reference dose rates. The problem of dose specification is discussed. For a number of theoretical implants predicted reference dose rates for the planned target volume were compared with the computer calculated dose rates for that volume. Discrepancies increase when moderate digressions from the adopted implant system rules are allowed, such as could commonly occur clinically. For a number of examples the degree of change in dose rate, if over 10%, and the position where this deviation is likely to occur are described. For optimal results the clinician should be well aware of these variations.


Assuntos
Braquiterapia , Braquiterapia/instrumentação , Braquiterapia/normas , Humanos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador
14.
Radiother Oncol ; 6(4): 257-65, 1986 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-3534966

RESUMO

Patients with T3 bladder cancer who survived surgery and proved to have P3a, P3b or P4a tumors were randomized to either no further treatment (61 patients) or postoperative total pelvic irradiation (55 patients). A three-fraction per day regime was adopted with a dose per fraction of 125 cGy and an interval of 3 h between fractions. The total dose amounted to 3750 cGy divided into 30 fractions over 12 days. Patients of the postoperative radiotherapy group were re-randomized to radiotherapy alone or radiotherapy plus misonidazole (MISO) in a daily dose of 1 g/m2 given orally 2 h before the first daily fraction. The 2-year disease-free survival rate in the cystectomy alone group was 33 +/- 6% compared to 65 +/- 6% in the postoperative radiotherapy group. The therapeutic benefit applied to the two cell types, all histological grades and stages and to patients with or without nodal metastases. The benefit of postoperative irradiation was also verified by the Cox's multivariant analysis which adjusts for the relative representation of the important prognostic factors particularly pathological stage and nodal involvement. MISO did not seem to add to the therapeutic gain. No late complications were encountered in the wall of the rectum, small bowel or uretero-intestinal anastomotic sites. This is suggested to be due to the small dose per fraction used. However, early small bowel reactions were dose-limiting.


Assuntos
Cistite/radioterapia , Cuidados Pós-Operatórios/métodos , Esquistossomose/radioterapia , Neoplasias da Bexiga Urinária/radioterapia , Adulto , Ensaios Clínicos como Assunto , Radioisótopos de Cobalto/uso terapêutico , Terapia Combinada , Cistite/mortalidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Misonidazol/efeitos adversos , Misonidazol/uso terapêutico , Estudos Prospectivos , Teleterapia por Radioisótopo , Dosagem Radioterapêutica , Distribuição Aleatória , Esquistossomose/mortalidade , Neoplasias da Bexiga Urinária/mortalidade
15.
Int J Radiat Oncol Biol Phys ; 12(8): 1329-33, 1986 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-3759554

RESUMO

The mean tumor intercapillary distance (ICD) was measured in 44 patients in Stages IIB and III carcinoma of the cervix uteri using a histo-chemical procedure for staining capillary endothelial cells. A mean ICD of 304 +/- 30 microns was obtained, which was independent of the clinical stage and histological grade of differentiation. For each tumor, the proportion of ICD's greater than an arbitrarily chosen value of 300 microns (approximately twice the maximum oxygen diffusion range) was calculated using the normal frequency distribution statistics. The mean ICD and this proportion decreased progressively during the course of external beam pelvic irradiation up to a dose of 4000 cGy. The mean ICD was greater in patients who suffered local recurrence within two years than in patients whose tumors remained controlled. This applied to pre-treatment values and measurements performed after the delivery of 2000 and 4000 cGy. The proportion of ICD's greater than 300 microns showed a similar trend. No significant correlation was found between the hemoglobin concentration at time of presentation and either the mean ICD, or the probability of local control. It is proposed that ICD measurement may be a useful tool to identify subgroups of tumors where hypoxia can interfere with the effectiveness of radiotherapy.


Assuntos
Carcinoma de Células Escamosas/irrigação sanguínea , Oxigênio/sangue , Tolerância a Radiação , Neoplasias do Colo do Útero/irrigação sanguínea , Capilares , Carcinoma de Células Escamosas/radioterapia , Feminino , Humanos , Neoplasias do Colo do Útero/radioterapia
16.
Int J Radiat Oncol Biol Phys ; 11(4): 715-23, 1985 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-3980268

RESUMO

The dose and volume data of 119 patients treated with radium or iridium-192 implants for cancer of the tongue, bladder or perineum are presented. The computer dosimetry system used in the Antoni van Leeuwenhoek Hospital permitted analysis of data regarding treated volume, dose variation inside the treated volume, patterns of geographical defects and their impact on the result of treatment. Dose was expressed in a number of ways, including prescribed (reference) and average dose and the CRE (Cumulative Radiation Effect) level attained. The CRE value included a time correction and a volume correction. The average dose proved to be the best predictor of local result in case of tongue and perineal implants. Great care is needed in case of tongue carcinoma to avoid a geographical miss by an inadequate treatment volume or geometric defects. The hypothesis that a dose reduction factor is necessary, in case of a high dose rate, could not be validated.


Assuntos
Braquiterapia , Neoplasias da Língua/radioterapia , Neoplasias da Bexiga Urinária/radioterapia , Feminino , Humanos , Irídio , Masculino , Pessoa de Meia-Idade , Períneo , Radioisótopos , Dosagem Radioterapêutica , Rádio (Elemento) , Fatores de Tempo
17.
Int J Radiat Oncol Biol Phys ; 10(12): 2265-72, 1984 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-6511523

RESUMO

Cell proliferation in carcinoma in the bilharzial bladder was studied in 92 patients in terms of the in vitro labeling index (LI), cell density (CD) and labeled cell density (LCD) using the in vitro 3H-Tdr technique. Cell proliferation was much greater in high than in low grade tumors and in deep than in superficial parts of the tumor, but was much less dependent on cell type; transitional cell cancer had the highest activity followed by squamous cell and adenocarcinoma. The probability of local recurrence after cystectomy decreased markedly when the LI exceeded 5.0%. The influence of the following three pre-operative radiotherapy regimens was studied: split-course (SC): the initial course consisted of 20 Gy in 10 treatments with a similar course was given after one week, hyper-fractionation using 17 treatments 0.6 Gy each on two successive days, this 2-day course of 20 Gy was repeated after one week, and concentrated irradiation consisting of two treatments, 6.0 Gy each with a gap of one week. Cystectomy was performed 14-20 days after treatment in all groups. Preoperative irradiation was generally associated with an increased probability of local control. The unfavorable influence of a high pretreatment LI was not noted after pre-operative irradiation. The CD was also reduced in proportion to the pretreatment LI. It is proposed that the response to irradiation was proportional to the initial proliferation activity and hence the prognostic significance of tumor grade and pretreatment LI was masked. Postirradiation tumor volume reduction was a strong predictor of treatment outcome. Concentrated irradiation was the least efficient pre-operative irradiation regimen and was associated with the least tumor volume reduction.


Assuntos
Carcinoma/etiologia , Esquistossomose/complicações , Doenças da Bexiga Urinária/complicações , Neoplasias da Bexiga Urinária/etiologia , Carcinoma/patologia , Carcinoma/radioterapia , Carcinoma/cirurgia , Divisão Celular/efeitos da radiação , Terapia Combinada , Humanos , Neoplasias da Bexiga Urinária/patologia , Neoplasias da Bexiga Urinária/radioterapia , Neoplasias da Bexiga Urinária/cirurgia
18.
Radiother Oncol ; 2(1): 1-8, 1984 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-6095372

RESUMO

The results of application of a protracted split-course radiotherapy regimen in T3 carcinoma in the bilharzial bladder are presented. A total dose of 70 Gy spread over 61 days was divided into four courses separated by gaps of 1, 2 and 1 week, respectively. Each of the first three sessions comprised eight fractions, 2.5 Gy each, while four such fractions were given during the fourth course. Patients were randomized between radiotherapy alone (32 patients) and radiotherapy plus misonidazole (MIS) (30 patients). The drug was given in a daily oral dose of 0.5 g/m2, 3.5 h prior to each radiation treatment. The treatment was well tolerated and MIS did not augment the radiation reaction. Mild or moderate peripheral neuropathy was experienced by 63% of patients of the group. Age and degree of upper obstructive uropathy were the most important determinants of the risk of neuropathy. The 2-year disease-free actuarial survival rates amounted to 58% and 44% in the MIS and radiotherapy alone groups respectively; the difference is not significant. The results were significantly better in case of transitional cell (67%) than squamous cell cancer (29%) but were independent of the histological grade. A strong correlation was found between the magnitude of tumour volume reduction after 40 Gy and the long-term end results.


Assuntos
Misonidazol/uso terapêutico , Nitroimidazóis/uso terapêutico , Esquistossomose/complicações , Doenças da Bexiga Urinária/complicações , Neoplasias da Bexiga Urinária/radioterapia , Idoso , Feminino , Seguimentos , Humanos , Rim/fisiopatologia , Masculino , Pessoa de Meia-Idade , Misonidazol/efeitos adversos , Doenças do Sistema Nervoso Periférico/induzido quimicamente , Radioterapia/efeitos adversos , Esquistossomose/tratamento farmacológico , Doenças da Bexiga Urinária/tratamento farmacológico
19.
Artigo em Inglês | MEDLINE | ID: mdl-6609798

RESUMO

The activities of penicillinases produced by Staphylococcus aureus, S9 were found to be affected by pH, temperature, substrate concentration and type of penicillin derivative used as a substrate. The optimal activities of penicillinases produced by S. aureus, S9 were obtained at pH 6, at 37 degrees C, 0.5-10 mu/ml penicillin G concentration, and by increasing the enzyme concentration.


Assuntos
Penicilinase/biossíntese , Staphylococcus aureus/enzimologia , Concentração de Íons de Hidrogênio , Penicilina G/metabolismo , Temperatura
20.
Am J Clin Oncol ; 6(1): 91-7, 1983 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-6301258

RESUMO

Twenty-one patients with Stage III or IV head and neck epidermoid cancer were treated by a three-fractions per day radiotherapy regime plus misonidazole (MIS). An initial course of 45 Gy was used, spread over 12 days and divided into 30 fractions 1.5 Gy each with a 3-hour interval between fractions. A daily MIS dose of 1 g/m2 was given 2 hours prior to the first fraction. A boost dose of 22.5 Gy/5 days was given to 10 patients, 4 weeks after the initial course, using the same fractionation scheme. The local acute and chronic reactions were acceptable. Eight patients suffered mild reversible peripheral neuropathy. The mean MIS blood level corresponded to an enhancement ratio of about 1.45. The 1-year disease-free survival rate was 9/21 and was significantly greater in patients receiving the boost irradiation. The control rate of nodal disease was encouraging. Based on this pilot study, a prospective trial is proposed aiming at testing the usefulness of MIS in MDF regimens in advanced head and neck cancer, either as the sole method of treatment or as a preoperative measure.


Assuntos
Carcinoma de Células Escamosas/terapia , Neoplasias de Cabeça e Pescoço/terapia , Misonidazol/uso terapêutico , Nitroimidazóis/uso terapêutico , Adulto , Idoso , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/radioterapia , Eritema/etiologia , Feminino , Neoplasias de Cabeça e Pescoço/mortalidade , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Masculino , Pessoa de Meia-Idade , Misonidazol/toxicidade , Doenças do Sistema Nervoso Periférico/induzido quimicamente , Projetos Piloto , Dosagem Radioterapêutica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...