RESUMEN
236U, 239Pu and 240Pu are present in soils mainly as a result of the local- and global-fallout from the atmospheric nuclear weapons tests carried out mainly in the 1950's and 1960's. In this work we provide new data on the presence of 236U and 239,240Pu in surface soils (i.e. up to 5â¯cm depth) from Chile and Africa. The results were obtained by low-energy Accelerator Mass Spectrometry (AMS). In the case of the Chilean samples, 236U/239Pu atom ratios show a high variability and are in general higher than the reported value for the global fallout in the Northern Hemisphere, ranging from 0.2 to 1.5. The 236U atomic concentrations range from 3.5â¯×â¯106 to 9.1â¯×â¯106 atoms/g, and are at least two orders of magnitude lower than the reported values in the Northern Hemisphere. The measured 240Pu/239Pu atom ratio in soils from South-Africa and Mozambique are of about 0.17, in agreement with the expected one for global-fallout at those coordinates. To best knowledge of the authors the present work is the first publication on 236U concentrations and 236U/239Pu atom ratios in soils from South-America and Africa.
Asunto(s)
Plutonio/análisis , Monitoreo de Radiación , Ceniza Radiactiva/análisis , Contaminantes Radiactivos del Suelo/análisis , Uranio/análisis , Chile , Armas Nucleares , SudáfricaRESUMEN
BACKGROUND: Use of breast magnetic resonance imaging (MRI) to detect breast cancer has generated significant debate. We analyze the role of breast MRI in the detection of additional disease and the need to perform additional biopsies in early breast carcinoma patients. In addition, we correlate the detection of new foci with tumor pathological features. METHODS: Early breast carcinoma patients that had undergone an MRI as well as a mammography as diagnostic procedures were included in the study. The following pathologic features were studied: carcinoma type, histological grade, estrogen receptors (ER), progesterone receptors (PR), HER2 and Ki67. Univariate analysis was conducted to ascertain significant correlation among detection of new foci and each of the tumor pathological features. RESULTS: Data from 98 patients have been analyzed: median age 49 years (range 35-79); carcinoma type: (a) infiltrative ductal carcinoma (n = 73, 74 %), (b) infiltrative lobular cancer (n = 12, 12 %), (c) ductal carcinoma in situ (n = 6, 6 %); amplified HER2 (n = 18, 18 %); grade III (n = 33, 33 %); Ki67 ≥ 25 % (n = 33, 33.67 %); positive ER and PR (n = 79, 80 %); triple negative tumors (n = 8, 8 %). MRI detected additional disease in 38 cases (39.58 %), and 20 led to an additional biopsy (20.4 %). Thirty-eight patients (39 %) underwent mastectomy. We found a statistically significant correlation between new foci in MRI and high Ki67 ≥ 25 % (p < 0.005). No other statistically significant correlation was established. CONCLUSION: MRI detected additional disease in 39 % cases, requiring an additional biopsy 20 %. Tumors with high proliferative index were significantly correlated with the detection of new foci in MRI.
Asunto(s)
Neoplasias de la Mama/diagnóstico , Carcinoma Ductal de Mama/diagnóstico , Carcinoma Intraductal no Infiltrante/diagnóstico , Carcinoma Lobular/diagnóstico , Imagen por Resonancia Magnética , Adulto , Anciano , Neoplasias de la Mama/metabolismo , Carcinoma Ductal de Mama/metabolismo , Carcinoma Intraductal no Infiltrante/metabolismo , Carcinoma Lobular/metabolismo , Detección Precoz del Cáncer , Femenino , Estudios de Seguimiento , Humanos , Persona de Mediana Edad , Clasificación del Tumor , Pronóstico , Receptor ErbB-2/metabolismo , Receptores de Estrógenos/metabolismo , Receptores de Progesterona/metabolismo , Estudios Retrospectivos , Tasa de SupervivenciaRESUMEN
INTRODUCTION: The purpose of this phase II study was to evaluate the efficacy and safety of neoadjuvant docetaxel/gemcitabine treatment in a biweekly regimen. MATERIALS AND METHODS: Patients with stage II/III breast cancer were treated with docetaxel (65 mg/m(2)) followed by gemcitabine (2500 mg/m(2)) every 2 weeks for 6 cycles. Patients with a clinical response or stable disease underwent mastectomy or breast-conserving surgery plus axillary dissection. After surgery, patients received 4 cycles of standard doxorubicin 60 mg/m(2) and cyclophosphamide 600 mg/m(2) every 21 days. RESULTS: Thirty-five patients were included in the trial. The overall response rate was 71.4% (95% CI: 53.7-85.4), with 8 complete and 17 partial responses. Breast conservation was possible in 59% of the patients. Toxicity was manageable. CONCLUSIONS: We consider biweekly docetaxel and gemcitabine could be an active and tolerable regimen option in the neoadjuvant setting sequentially with standard adjuvant doxorubicin-cyclophosphamide in patients with stage II or III breast cancer.
Asunto(s)
Antineoplásicos/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/patología , Ciclofosfamida/uso terapéutico , Desoxicitidina/análogos & derivados , Doxorrubicina/uso terapéutico , Taxoides/administración & dosificación , Adulto , Anciano , Quimioterapia Adyuvante , Desoxicitidina/administración & dosificación , Docetaxel , Esquema de Medicación , Femenino , Humanos , Persona de Mediana Edad , Terapia Neoadyuvante , Estadificación de Neoplasias , GemcitabinaRESUMEN
"On the basis of a body of empirical research, the authors explore the relationship between agrarian structure and population [in Latin America]. After an introduction in which they present their theoretical and methodological orientation, they describe the current changing trends in agrarian structure, among which are the 'intensification' of the process of the penetration of capitalistic forms into agriculture." They then discuss the relationships between agrarian structure and demographic variables, particularly fertility and migration. In the final section, some guidelines for future research are presented. This paper is a revised version of an evaluation study carried out to assess the contributions of 14 research projects financed by the Programme of Social Research on Population in Latin America (PISPAL).
Asunto(s)
Agricultura , Demografía , Estudios de Evaluación como Asunto , Dinámica Poblacional , Países en Desarrollo , Economía , Emigración e Inmigración , Fertilidad , América Latina , Población , Planificación SocialRESUMEN
PIP: The population of the world today is approximately 3900 million of which 2800 million come from developing countries. What is most noteworthy about the statistics is the rate at which the population is growing. Only 25 years ago there were about 2500 million people on the earth; in the next 25 years there will be 2500 million more. The upsurge is due in great measure to decreases in mortality rates due to scientific advances without corresponding declines in fertility. The uneven declines in fertility and mortality have also rejuvenated world age structure, especially in developing countries where over 40% of the population is under 15. Such an age structure carries an implicit growth potential however drastic future reductions in fertility may be. Projections for the year 2000 are for 600 million more women between the ages of 15-44. Even developed countries with low growth rates will not achieve net reproduction rates of 1 before 2020. After a net rate of 1 is achieve it takes 50 years to arrive at zero population growth. Another aspect of world population increase is urbanization which has resulted in mass transfers of people from rural and small urban areas to ever-growing agglomerations. It is anticipated that by 2000, half the people of the world will be urban dwellers; in 1975, the figure was 38%. Such mass migration will definitely have socioeconomic consequences.^ieng