Search results for "Low dose"
showing 10 items of 66 documents
530MO Clinical benefit in biomarker-positive patients (pts) with locally advanced or metastatic solid tumours treated with the PARP1/2 inhibitor pami…
2020
Second follow-up of a German cohort on childhood cancer incidence after exposure to postnatal diagnostic x-ray.
2019
Studies on children exposed to ionizing radiation by computed tomography (CT) indicate an increased risk of leukemia and central nervous system (CNS) tumors. Evidence of the risks associated with diagnostic X-ray examinations, the most frequent examination in pediatric radiology, in which the radiation dose is up to 750 times lower compared to CT examinations, is less clear.a#13; This study presents results of the second follow-up for the risk of childhood cancer in a cohort of children (alt;15 years) with diagnostic X-ray exposure at a large German hospital during 1976-2003 followed for additional 10 years until 2016.a#13; With a latency period of six months, 92,998 children contributed 79…
Mutational Profiling Predicts Clinical Outcomes to Azacytidine and Low Dose Cytarabine Plus Fludarabine (FLUGA) in Elderly Acute Myeloid Leukemia Pat…
2019
BACKGROUND: Older patients with acute myeloid leukaemia (AML) who are unsuitable for standard induction therapy have limited treatment options. While DNMT3A, TET2, IDH1/2 and TP53 mutations have been previously associated to better response to hypomethylating agents, there are no molecular biomarkers for low-dose cytarabine (LDAC)-based regimens. AIMS: To predict outcome in AML older patients at diagnosis based on mutation status in the context of FLUGAZA trial. FLUGAZA trial was focus on >65 years AML de novo patients comparing azacytidine vs. fludarabine and LDAC (FLUGA Scheme). METHODS: We analyzed bone marrow (BM) samples at diagnosis from 209 out of 285 AML patients treated accordin…
Impact of medical imaging on the epigenome – low-dose exposure in the course of computed tomography does not induce detectable changes of DNA-methyla…
2021
Computed tomography (CT) is a main contributor to artificial low-dose exposure. Understanding the biological effects induced by CT exposure and their dependency on the characteristics of photon spectra is essential for knowledge-driven risk assessment. In a previous gene expression study, we have identified upregulation of AEN, BAX, DDB2, EDA2R and FDXR after ex vivo exposure with single-energy CT and dual-energy CT (DECT). In this study, we focused on CT-induced changes of DNA methylation. This epigenetic modification of DNA is a central regulator of gene expression and instrumental in preserving genome integrity. Previous studies reported focal hypermethylation and global hypomethylation …
Acute effects of low doses of methyl parathion on human EEG.
2005
Abstract Biological monitoring of workers exposed to organophosphates consists mainly of measuring serum or erythrocyte cholinesterase activity. However, animal experiments and a field study suggest that quantitative analysis of EEG may be more sensitive. In a parallel group design, 25 farmers were investigated, spraying methyl parathion or water for 50 min. EEG was recorded before and after spraying. Serum and erythrocyte cholinesterase activity was compared with intraindividual pre-exposure values. Plasma methyl parathion concentrations ranged up to 12.1 μg/l, methyl paraoxon was not detectable. Based on plasma concentrations, two exposed subgroups were defined. In EEG recorded with close…
Monte Carlo calculation of dose rate distributions around the Walstam CDC.K-type137Cs sources
2001
Basic dosimetric data for the Walstam CDC.K-type low dose rate 137Cs sources in water have been calculated using Monte Carlo techniques. These sources, CDC.K1 -K3 and CDC.K4, are widely used in a range of applicators and moulds for the treatment of intracavitary and superficial cancers. Our purpose is to improve existing data about these sources using the Monte Carlo simulation code GEANT3. Absolute dose rate distributions in water have been calculated around these sources and are presented as conventional 2D Cartesian look-up tables. Also the AAPM Task Group 43 formalism for dose calculation has been applied. The calculated dose rate constant for the CDC.K1-K3 source is A = 1.106 +/- 0.001…
SU-E-T-508: Monte Carlo Dosimetric Study of the CSM40 Low Dose Rate Source
2013
Purpose: There is a LDR 137Cs brachytherapy source, CSM40, developed by Eckert & Ziegler BEBIG. Fundamental dosimetric datasets to be used on treatment planning systems do not exist for this source. This study aims to obtain quality dosimetric data for this source for its use in clinical practice as required by AAPM and ESTRO. Methods: Penelope2008 and GEANT4 Monte Carlo codes were used to characterize this source dosimetry. Water composition and mass density was that recommended by AAPM. Due to the typical energies of the 137 Cs, dose for small distances can be approximated by collisional kerma. Therefore, we have considered collisional kerma for r<20 cm. To provide adequate spatial resolu…
Pre-treatment with high doses of cocaine decreases the reinforcing effects of cocaine in the conditioned place preference paradigm.
2012
The aim of the present study was to determine if pre-exposure to high doses of cocaine can subsequently alter the rewarding effects of this drug. Adult male mice received a pretreatment of physiological saline, or 12.5 or 25 mg/kg of cocaine (one injection a day for five days). After an interval of six days without injections, the rewarding effects of low doses of cocaine (0.5, 1 or 1.5 mg/kg) were evaluated in the conditioned place preference (CPP) paradigm. Doses of 1 and 1.5 mg/kg induced a clear CPP in animals pre-treated with saline but were ineffective in those pre-treated with 25 mg/kg of cocaine. Only the dose of 1.5 mg/kg induced CPP in mice pre-treated with 12.5 mg/kg of cocaine. …
Intermittent Low-Dose IFN Gamma Treatment for Metastatic Renal Cell Carcinoma: Analysis of Factors Predicting Clinical Response and Long-Term Survival
1995
Background: Objective tumor remissions are induced by a variety of immunomodulating agents in a minority of patients suffering from metastasizing renal cell carcinoma. The results of different clinical studies, however, varied greatly for each of these treatment modalities. In order to elucidate potential causes for this variability and to further study the long-term results of intermittent low-dose IFN gamma therapy in patients with advanced renal cell cancer (RCC) we retrospectively analyzed factors predicting clinical response and long-term survival of 121 patients. Material and Methods: We retrospectively analyzed the clinical results of 5 phase II studies treating 121 patients with int…
Low Dose-Rate, High Total Dose Set-Up for Rad-Hard CMOS I/O Circuits Testing
2017
In this paper, the planning of low dose-rate, high total dose testing campaign for I/O circuits is reported. In particular, the paper describes all development steps, starting from the rad-hard I/O circuits design and the implementation of the test-chip, which is meant to allow comparative testing between rad-hard and standard devices. The designed experimental setup permits in situ measurements, therefore the circuits behavior can be remotely monitored for very long periods. This feature enables low dose-rate testing up to very high dose.