Challenges in treating radioiodine-refractory thyroid cancer: a global perspective with a focus on developing nations in Latin America.

PURPOSE: This article aims to comprehensively analyze the unique challenges in managing patients with metastatic Differentiated Thyroid Cancer (DTC) that develop radioiodine-refractory disease, especially in developing countries in Latin America. We discuss key contentious aspects of their treatment, such as the optimal timing for initiating systemic therapy, the choice of first-line medications, the appropriate timing for requesting molecular interrogation, and the challenges associated with accessing these drugs and molecular panels. METHODS: To illustrate these challenges and enhance understanding, we present five real clinical cases from the authors' experiences. RESULTS: Patients with Differentiated Thyroid Cancer (DTC) generally have an excellent prognosis, with an overall 10-year survival rate exceeding 97%. However, approximately 5% of DTC patients, especially those with distant metastases, may develop radioiodine-refractory disease, reducing survival rates. Access to medications remains difficult and time-consuming, particularly for patients within the public healthcare system. Urgent discussions on drug pricing involving all stakeholders are imperative. To break free from complacency, stakeholders must prioritize patient well-being by advocating for evidence-based drug pricing, increased participation in clinical trials, and streamlined regulatory processes. CONCLUSION: Beyond the recognized need for prospective randomized clinical trials to determine the optimal first-line drug and the timing of molecular testing, this type of manuscript plays a pivotal role in stimulating discussions and disseminating comprehensive knowledge about the challenges associated with treating and monitoring patients with radioiodine-refractory thyroid carcinoma, especially in developing countries.

BACTERIAL COMMUNITY DYNAMICS AND ECOTOXICOLOGICAL ASSESSMENT DURING BIOREMEDIATION OF SOILS CONTAMINATED BY BIODIESEL AND DIESEL/BIODIESEL BLENDS.

The gradual introduction of biodiesel in the Brazilian energy landscape has primarily occurred through its blending with conventional petroleum diesel (e.g., B20 (20% biodiesel) and B5 (5% biodiesel) formulations). Because B20 and lower-level blends generally do not require engine modifications, their use as transportation fuel is increasing in the Brazilian distribution networks. However, the environmental fate of low-level biodiesel blends and pure biodiesel (B100) is poorly understood and the ecotoxicological-safety endpoints of biodiesel-contaminated environments are unknown. Using laboratory microcosms consisting of closed reactor columns filled with clay loam soil contaminated with pure biodiesel (EXPB100) and a low-level blend (EXPB5) (10% w/v), this study presents soil ecotoxicity assessement and dynamics of culturable heterotrophic bacteria. Most-probable-number (MPN) procedures for enumeration of bacteria, dehydrogenase assays and soil ecotoxicological tests using Eisenia fetida have been performed at different column depths over the course of incubation. After 60 days of incubation, the ecotoxicity of EXPB100-derived samples showed a decrease from 63% of mortality to 0% while EXPB5-derived samples exhibited a reduction from 100% to 53% and 90% on the top and at the bottom of the reactor column, respectively. The dehydrogenase activity of samples from EXPB100 and EXPB5 increased significantly compared to pristine soil after 60 days of incubation. Growth of aerobic bacterial biomass was only observed on the top of the reactor column while the anaerobic bacteria exhibited significant growth at different column depths in EXPB100 and EXPB5. These preliminary results suggest the involvement of soil indigenous microbiota in the biodegradation of biodiesel and blends. However, GC-FID analyses for quantification of fatty acid methyl esters (FAMEs) and aliphatic hydrocarbons and targeted sequencing of 16S rRNA tags using illumina platforms will provide important insights into the profiles and underlying mechanisms of (bio)diesel biodegradation in soil environments.

The high level of aluminum resistance in signalgrass is not associated with known mechanisms of external aluminum detoxification in root apices.

Al resistance of signalgrass (Brachiaria decumbens Stapf cv Basilisk), a widely sown tropical forage grass, is outstanding compared with the closely related ruzigrass (Brachiaria ruziziensis Germain and Evrard cv Common) and Al-resistant genotypes of graminaceous crops such as wheat, triticale, and maize. Secretion of organic acids and phosphate by root apices and alkalinization of the apical rhizosphere are commonly believed to be important mechanisms of Al resistance. However, root apices of signalgrass secreted only moderately larger quantities of organic acids than did those of ruzigrass, and efflux from signalgrass apices was three to 30 times smaller than from apices of Al-resistant genotypes of buckwheat, maize, and wheat (all much more sensitive to Al than signalgrass). In the presence, but not absence, of Al, root apices of signalgrass alkalinized the rhizosphere more than did those of ruzigrass. The latter was associated with a shortening of the alkalinizing zone in Al-intoxicated apices of ruzigrass, indicating that differences in alkalinizing power were a consequence, not a cause of, differential Al resistance. These data indicate that the main mechanism of Al resistance in signalgrass does not involve external detoxification of Al. Therefore, highly effective resistance mechanisms based on different physiological strategies appear to operate in this species.

Roots of nutrient-deprived Brachiaria species accumulate 1,3-di-O-trans-feruloylquinic acid.

A novel di-hydroxycinnamoylquinic acid ester, 1,3-di-O-trans-feruloylquinic acid (DFQA), was isolated from roots of nutrient-deprived Brachiaria species--the most widely sown tropical forage grasses in South America. In contrast to other so far characterized quinic-acid esters, DFQA exists in a chair conformation with the carboxylic group in the axial orientation. It accumulates in older parts of the root system, but not in root apices or shoots. Higher levels were found in B. ruziziensis, which is poorly adapted to infertile acid soils, than in well adapted B. decumbens. DFQA was also found in the soil, most likely as a result of root decay, because it was not detected in root exudates of plants cultivated in solution culture. Nitrogen and phosphorus deficiency--but not aluminum toxicity or deprivation of other nutrients--stimulated its synthesis in roots. Its accumulation was correlated with a shift in biomass partitioning toward the root system.