Search

Os estudos foram realizados visando estabelecer protocolo para propagação in vitro de gloxínia (Sinningia speciosa Lood. Hiern.), através da atualização do efeito de diferentes concentrações do meio de Murashige & Skoog - MS (0, SO, 100 e 150%), do efeito de meio líquido ou sólido (7 g/L de ágar) e de reguladores de crescimento: 6Benzilaminopurina - BAP (O; 0,5; 1 e 2 mg/L) x Ácido Naftaleno Acético - ANA (O; 0,25; 0,5; e lmg/L); Thidiazuron - TDZ (O; 0,1; 0,2; 0,4; 0,8 e 1,6 mg/L) x ANA (O; 0,1 e 1 mg/L) e Ácido Ciberélico - GA, (O; 0,5; 1; 2 e 4 mg/L) x ANA (O; 0,1 e 1 mg/L). Avaliando o efeito do parcelamento do meio de cultura e de meio sólido ou líquido, os resultados indicaram que melhor desenvolvimento da planta e maior número de brotos ocorrem em meio constituído de 50% de MS, solidificado com ágar. Maior número de brotos pode ser obtido utilizando 0,86 mg/L de TDZ em combinação com O ou 0,1 mg/L de ANA e brotos com maior tamanho podem ser produzidos em 0,90 mg/L de TDZ e 0,1 mg/L de ANA. A utilização de ANA induziu a formação de calos, independente do regulador de crescimento presente, enquanto que raizes foram formadas na ausência de ANA ou na concentração 0,1 mg/L.

Background: The 10 key characteristics (KCs) of carcinogens form the basis of a framework to identify, organize, and evaluate mechanistic evidence relevant to carcinogenic hazard identification. The 10 KCs are related to mechanisms by which carcinogens cause cancer. The International Agency for Research on Cancer ( IARC ) Monographs programme has successfully applied the KCs framework for the mechanistic evaluation of different types of exposures, including chemicals, metals, and complex exposures, such as environmental, occupational, or dietary exposures. The use of this framework has significantly enhanced the identification and organization of relevant mechanistic data, minimized bias in evaluations, and enriched the knowledge base regarding the mechanisms of known and suspected carcinogens., Objectives: We sought to report the main outcomes of an IARC Scientific Workshop convened by the IARC to establish appropriate, transparent, and uniform application of the KCs in future IARC Monographs evaluations., Methods: A group of experts from different disciplines reviewed the IARC Monographs experience with the KCs of carcinogens, discussing three main themes: a ) the interpretation of end points forming the evidence base for the KCs, b ) the incorporation of data from novel assays on the KCs, and c ) the integration of the mechanistic evidence as part of cancer hazard identification. The workshop participants assessed the relevance and the informativeness of multiple KCs-associated end points for the evaluation of mechanistic evidence in studies of exposed humans and experimental systems., Discussion: Consensus was reached on how to enhance the use of in silico , molecular, and cellular high-output and high-throughput data. In addition, approaches to integrate evidence across the KCs and opportunities to improve methodologies of mechanistic evaluation of cancer hazards were explored. The findings described herein and in a forthcoming IARC technical report will support future working groups of experts in reporting and interpreting results under the KCs framework within the IARC Monographs or in other contexts. https://doi.org/10.1289/EHP15389.

Purpose: Childhood cancer survivors, in particular those treated with radiation therapy, are at high risk of long-term iatrogenic events. The prediction of risk of such events is mainly based on the knowledge of the radiation dose received to healthy organs and tissues during treatment of childhood cancer diagnosed decades ago. We aimed to set up a standardized organ dose table to help former patients and clinicians in charge of long-term follow-up clinics., Methods and Materials: We performed whole body dosimetric reconstruction for 2646 patients from 12 European countries treated between 1941 and 2006 (median, 1976). Most plannings were 2- or 3-dimensional. A total of 46% of patients were treated using Cobalt 60, and 41%, using a linear accelerator. The median prescribed dose was 27.2 Gy (IQ1-IQ3, 17.6-40.0 Gy). A patient-specific voxel-based anthropomorphic phantom with more than 200 anatomic structures or substructures delineated as a surrogate of each subject's anatomy was used. The radiation therapy was simulated with a treatment planning system based on available treatment information. The radiation dose received by any organ of the body was estimated by extending the treatment planning system dose calculation to the whole body, by type and localization of childhood cancer., Results: The integral dose and normal tissue doses to most of the 23 considered organs increased between the 1950s and 1970s and decreased or plateaued thereafter. Whatever the organ considered, the type of childhood cancer explained most of the variability in organ dose. The country of treatment explained only a small part of the variability., Conclusions: The detailed dose estimates provide very useful information for former patients or clinicians who have only limited knowledge about radiation therapy protocols or techniques, but who know the type and site of childhood cancer, sex, age, and year of treatment. This will allow better prediction of the long-term risk of iatrogenic events and better referral to long-term follow-up clinics., (Copyright © 2024. Published by Elsevier Inc.)

Background: Despite the excellent disease-specific survival associated with low-risk differentiated thyroid cancer (DTC), its diagnosis and management have been linked to patient concerns about cancer recurrence, treatment-related health risks, and mortality. Lack of information regarding long-term health outcomes can perpetuate these concerns. Therefore, we assessed all-cause and cause-specific mortality in a large cohort of individuals diagnosed with low-risk DTC. Methods: From the U.S. Surveillance, Epidemiology, and End Results-12 cancer registry database (1992-2019), we identified 51,854 individuals (81.8% female) diagnosed with first primary DTC at low risk of recurrence (≤4 cm, localized). We estimated cause-specific cumulative mortality by time since diagnosis, accounting for competing risks. Standardized mortality ratios (SMRs) and CIs were used to compare observed mortality rates in DTC patients with expected rates in the matched U.S. general population, overall and by time since DTC diagnosis. We used Cox proportional hazards models to examine associations between radioactive iodine (RAI) treatment and cause-specific mortality. Results: During follow-up (median = 8.8, range 0-28 years), 3467 (6.7%) deaths were recorded. Thyroid cancer accounted for only 4.3% of deaths ( n  = 148). The most common causes of death were malignancies (other than thyroid cancer) ( n  = 1031, 29.7%) and cardiovascular disease (CVD; n  = 912, 26.3%). The 20-year cumulative mortality rate from thyroid cancer, malignancies (other than thyroid or nonmelanoma skin cancer), and CVD was 0.6%, 4.6%, and 3.9%, respectively. Lower than expected mortality was observed for all causes excluding thyroid cancer (SMR = 0.69 [CI 0.67-0.71]) and most specific causes, including all malignancies combined (other than thyroid cancer; SMR = 0.80 [CI 0.75-0.85]) and CVD (SMR = 0.64 [CI 0.60-0.69]). However, mortality rates were elevated for specific cancers, including pancreas (SMR = 1.58 [CI 1.18-2.06]), kidney and renal pelvis (SMR = 1.85 [CI 1.10-2.93]), and brain and other nervous system (SMR = 1.62 [CI 0.99-2.51]), and myeloma (SMR = 2.35 [CI 1.46-3.60]) and leukemia (SMR = 1.62 [CI 1.07-2.36]); these associations were stronger ≥10 years after diagnosis. RAI was not associated with risk of cause-specific death, but numbers of events were small and the range of administered activities was likely narrow. Conclusions: Overall, our findings provide reassurance regarding low overall and cause-specific mortality rates in individuals with low-risk DTC. Additional research is necessary to confirm and understand the increased mortality from certain subsequent cancers.

Background: Thyroid cancer incidence has increased worldwide. Obesity trends may play a role, but the underlying biological pathways are not well-characterized. Therefore, we examined associations of excess adiposity and obesity-related metabolic conditions with thyroid cancer incidence., Methods: From the Sister Study, a cohort of sisters of women with breast cancer, we included 47,739 women who were cancer-free at baseline (2003-2009). Height, weight, waist and hip circumference, and blood pressure were measured at baseline and medical history was self-reported. Cox proportional hazards regression models were adjusted for age (time scale), race/ethnicity, smoking, baseline history of benign thyroid disease, and frequency of routine healthcare visits., Findings: During follow-up (median = 12.5; max = 15.9 years), 259 women reported incident thyroid cancer. Body mass index (BMI) (hazard ratio [HR] per-5 kg/m 2  = 1.25, 95% CI = 1.14-1.37), waist circumference (HR per-5 cm increase  = 1.11, 95% CI = 1.06-1.15), and waist-to-hip ratio (HR  ≥0.85-versus-<0.85  = 1.49, 95% CI = 1.14-1.94) were positively associated with thyroid cancer incidence, as were metabolic syndrome (HR = 1.67, 95% CI = 1.24-2.25), dyslipidemia (HR = 1.46, 95% CI = 1.13-1.90), borderline diabetes (HR = 2.06, 95% CI = 1.15-3.69), hypertension (HR = 1.49, 95% CI = 1.12-1.96), and polycystic ovary syndrome (PCOS, HR = 2.10, 95% CI = 1.20-3.67). These associations were attenuated with additional BMI adjustment, although dyslipidemia (HR = 1.35, 95% CI = 1.04-1.75) and PCOS (HR = 1.86, 95% CI = 1.06-3.28) remained associated with thyroid cancer incidence. Hypothyroidism was not associated with thyroid cancer., Interpretation: In this cohort of sisters of women diagnosed with breast cancer, excess adiposity and several obesity-related metabolic conditions were associated with thyroid cancer incidence. These findings provide insights into potential biological mechanisms linking obesity and thyroid cancer., Funding: This research was supported by the Intramural Research Program of the National Institutes of Health, National Cancer Institute and National Institute of Environmental Health Sciences (Z01-ES044005)., Competing Interests: All authors declare no conflict of interest.

Use of radioactive iodine (RAI) for thyroid cancer patients is accompanied by elevated risks of radiation-induced adverse effects due to significant radiation exposure of normal tissues or organs other than the thyroid. The health risk estimation for thyroid cancer patients should thus be preceded by estimating normal tissue doses. Although organ dose estimation for a large cohort often relies on absorbed dose coefficients (i.e. absorbed dose per unit activity administered, mGy MBq -1 ) based on population models, no data are available for thyroid cancer patients. In the current study, we calculated absorbed dose coefficients specific for adult thyroid cancer patients undergoing RAI treatment after recombinant human TSH (rhTSH) administration or thyroid hormone withdrawal (THW). We first adjusted the transfer rates in the biokinetic model previously developed for THW patients for use in rhTSH patients. We then implemented the biokinetic models for thyroid cancer patients coupled with S values from the International Commission on Radiological Protection (ICRP) reference voxel phantoms to calculate absorbed dose coefficients. The biokinetic model for rhTSH patients predicted the extrathyroidal iodine decreasing noticeably faster than in the model for THW patients (calculated half-times of 12 and 15 h for rhTSH administration and THW, respectively). All dose coefficients for rhTSH patients were lower than those for THW patients with the ratio (rhTSH administration/THW) ranging from 0.60 to 0.95 (mean = 0.67). The ratio of the absorbed dose coefficients in the current study to the ICRP dose coefficients, which were derived from models for normal subjects, varied widely from 0.21 to 7.19, stressing the importance of using the dose coefficients for thyroid cancer patients. The results of this study will provide medical physicists and dosimetrists with scientific evidence to protect patients from excess exposure or to assess radiation-induced health risks caused by RAI treatment., (© 2023 Society for Radiological Protection. Published on behalf of SRP by IOP Publishing Limited. All rights reserved.)

The exponential growth in the use of nuclear medicine procedures represents a general radiation safety concern and stresses the need to monitor exposure levels and radiation-related long term health effects in NM patients. In the current study, following our previous work on NCINM version 1 based on the UF/NCI hybrid phantom series, we calculated a comprehensive library of S values using the ICRP reference pediatric and adult voxel phantoms and established a library of biokinetic data from multiple ICRP Publications, which were then implemented into NCINM version 2. We calculated S values in two steps: calculation of specific absorbed fraction (SAF) using a Monte Carlo radiation transport code combined with the twelve ICRP pediatric and adult voxel phantoms for a number of combinations of source and target region pairs; derivation of S values from the SAFs using the ICRP nuclear decay data. We also adjusted the biokinetic data of 105 radiopharmaceuticals from multiple ICRP publications to match the anatomical description of the ICRP voxel phantoms. Finally, we integrated the ICRP phantom-based S values and adjusted biokinetic data into NCINM version 2. The ratios of cross-fire SAFs from NCINM 2 to NCINM 1 for the adult phantoms varied widely from 0.26 to 5.94 (mean = 1.24, IQR = 0.77-1.55) whereas the ratios for the pediatric phantoms ranged from 0.64 to 1.47 (mean = 1.01, IQR = 0.98-1.03). The ratios of absorbed dose coefficients from NCINM 2 over those from ICRP publications widely varied from 0.43 (colon for 99m Tc-ECD) to 2.57 (active marrow for 99m Tc-MAG3). NCINM 2.0 should be useful for dosimetrists and medical physicists to more accurately estimate organ doses for various nuclear medicine procedures., (© 2022 IOP Publishing Ltd.)

Background: In response to evidence of overdiagnosis and overtreatment of papillary thyroid carcinoma (PTC), the 2009 and 2015 American Thyroid Association (ATA) adult guidelines recommended less extensive surgery (lobectomy vs. total thyroidectomy) and more restricted use of postsurgical radioactive iodine (RAI) in management of PTC at low risk of recurrence. In 2015, active surveillance was suggested as a viable option for some <1-cm PTCs, or microcarcinomas. The 2015 ATA pediatric guidelines similarly shifted toward more restricted use of RAI for low-risk PTCs. The impact of these recommendations on low-risk adult and pediatric PTC management remains unclear, particularly after 2015. Methods: Using data from 18 Surveillance, Epidemiology, and End Results (SEER) U.S. registries (2000-2018), we described time trends in reported first-course treatment (total thyroidectomy alone, total thyroidectomy+RAI, lobectomy, no surgery, and other/unknown) for 105,483 patients diagnosed with first primary localized PTC (without nodal/distant metastases), overall and by demographic and tumor characteristics. Results: The declining use of RAI represented the most pronounced change in management of PTCs <4 cm (44-18% during the period 2006-2018), including microcarcinomas (26-6% during the period 2007-2018). In parallel, an increasing proportion of PTCs were managed with total thyroidectomy alone (35-54% during the period 2000-2018), while more subtle changes were observed for lobectomy (declining from 23% to 17% during the period 2000-2006, stabilizing, and then rising from 17% to 24% during the period 2015-2018). Use of nonsurgical management did not meaningfully change over time, impacting <1% of microcarcinomas annually during the period 2000-2018. Similar treatment trends were observed by sex, age, race/ethnicity, metropolitan vs. nonmetropolitan residence, and insurance status. For pediatric patients (<20 years), use of RAI peaked in 2009 (59%), then decreased markedly to 11% (2018), while use of total thyroidectomy alone and, to a lesser extent, lobectomy increased. No changing treatment trends were observed for ≥4-cm PTCs. Conclusions: The declining use of RAI in management of low-risk adult and pediatric PTC is consistent with changing recommendations from the ATA practice guidelines. Post-2015 trends in use of lobectomy and nonsurgical management of low-risk PTCs, particularly microcarcinomas, were more subtle than expected; however, these trends may change as evidence regarding their safety continues to emerge.

20 years ago, 3 manuscripts describing doses and potential cancer risks from CT scans in children raised awareness of a growing public health problem. We reviewed the epidemiological studies that were initiated in response to these concerns that assessed cancer risks from CT scans using medical record linkage. We evaluated the study methodology and findings and provide recommendations for optimal study design for new efforts. We identified 17 eligible studies; 13 with published risk estimates, and 4 in progress. There was wide variability in the study methodology, however, which made comparison of findings challenging. Key differences included whether the study focused on childhood or adulthood exposure, radiosensitive outcomes ( e.g. leukemia, brain tumors) or all cancers, the exposure metrics ( e.g. organ doses, effective dose or number of CTs) and control for biases ( e.g. latency and exclusion periods and confounding by indication). We were able to compare results for the subset of studies that evaluated leukemia or brain tumors. There were eight studies of leukemia risk in relation to red bone marrow (RBM) dose, effective dose or number of CTs; seven reported a positive dose-response, which was statistically significant ( p < 0.05) in four studies. Six of the seven studies of brain tumors also found a positive dose-response and in five, this was statistically significant. Mean RBM dose ranged from 6 to 12 mGy and mean brain dose from 18 to 43 mGy. In a meta-analysis of the studies of childhood exposure the summary ERR/100 mGy was 1.78 (95%CI: 0.01-3.53) for leukemia/myelodisplastic syndrome ( n = 5 studies) and 0.80 (95%CI: 0.48-1.12) for brain tumors ( n = 4 studies) (p-heterogeneity >0.4). Confounding by cancer pre-disposing conditions was unlikely in these five studies of leukemia. The summary risk estimate for brain tumors could be over estimated, however, due to reverse causation. In conclusion, there is growing evidence from epidemiological data that CT scans can cause cancer. The absolute risks to individual patients are, however, likely to be small. Ongoing large multicenter cohorts and future pooling efforts will provide more precise risk quantification.

The last decades have seen increased concern about the possible effects of low to moderate doses of ionizing radiation (IR) exposure on cognitive function. An interdisciplinary group of experts (biologists, epidemiologists, dosimetrists and clinicians) in this field gathered together in the framework of the European MELODI workshop on non-cancer effects of IR to summarise the state of knowledge on the topic and elaborate research recommendations for future studies in this area. Overall, there is evidence of cognitive effects from low IR doses both from biology and epidemiology, though a better characterization of effects and understanding of mechanisms is needed. There is a need to better describe the specific cognitive function or diseases that may be affected by radiation exposure. Such cognitive deficit characterization should consider the human life span, as effects might differ with age at exposure and at outcome assessment. Measurements of biomarkers, including imaging, will likely help our understanding on the mechanism of cognitive-related radiation induced deficit. The identification of loci of individual genetic susceptibility and the study of gene expression may help identify individuals at higher risk. The mechanisms behind the radiation induced cognitive effects are not clear and are likely to involve several biological pathways and different cell types. Well conducted research in large epidemiological cohorts and experimental studies in appropriate animal models are needed to improve the understanding of radiation-induced cognitive effects. Results may then be translated into recommendations for clinical radiation oncology and imaging decision making processes., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Extraskeletal myxoid chondrosarcoma is a rare form of malignant mesenchymal neoplasm mainly localized into the limbs, particularly in the thigh and popliteal fossa. It has been classified as a low-grade sarcoma so far, but it shows a tendency to relapse and metastasize. In the early stage of disease, surgery represents the only chance of cure. In case of diffuse metastatic disease, systemic chemotherapy with anthracyclines is the standard of care. In this paper, we present a case of a patient affected by this rare disease and the analysis of radiological, surgical and histopathological aspects., (Published by Oxford University Press and JSCR Publishing Ltd. © All rights reserved. The Author(s) 2020.)