Mercury Pollution History in Tropical and Subtropical American Lakes: Multiple Impacts and the Possible Relationship with Climate Change

Sediment cores obtained from 11 tropical and subtropical American lakes revealed that local human activities significantly increased mercury (Hg) inputs and pollution levels. Remote lakes also have been contaminated by anthropogenic Hg through atmospheric depositions. Long-term sediment-core profiles revealed an approximately 3-fold increase in Hg fluxes to sediments from c. 1850 to 2000. Generalized additive models indicate that c. 3-fold increases in Hg fluxes also occurred since 2000 in the remote sites, while Hg emissions from anthropogenic sources have remained relatively stable. The tropical and subtropical Americas are vulnerable to extreme weather events. Air temperatures in this region have shown a marked increase since the 1990s, and extreme weather events arising from climate change have increased. When comparing Hg fluxes to recent (1950-2016) climatic changes, results show marked increases in Hg fluxes to sediments during dry periods. The Standardized Precipitation-Evapotranspiration Index (SPEI) time series indicate a tendency toward more extreme drier conditions across the study region since the mid-1990s, suggesting that instabilities in catchment surfaces caused by climate change are responsible for the elevated Hg flux rates. Drier conditions since c. 2000 appear to be promoting Hg fluxes from catchments to lakes, a process that will likely be exacerbated under future climate-change scenarios.

In flux: Annual transport and deposition of suspended heavy metals and trace elements in the urbanised, tropical Red River Delta, Vietnam

Due to the depositional environment, river deltas are said to act as filters and sinks for pollutants. However, many deltas are also densely populated and rapidly urbanizing, creating new and increased sources of pollutants. These sources pose the risk of tipping these environments from pollution sinks to sources, to the world's oceans. We provide detailed seasonal and annual assessments of metal contaminants in riverine suspended particulate matter (SPM) across the densely populated Red River Delta (RRD), Vietnam. The global contributions of elements from the RRD are all <0.2% with many elemental fluxes <0.01%, suggesting the RRD is not a major source of elemental pollution to the ocean. However, 'hotspots' of metal pollution due to human activity and the impacts of tropical storm Son Tinh (July 2018) exceed both national level regulations and international measures of toxicity (e.g. enrichment factors). There is widespread 'extreme pollution' of Cd (enrichment factor >40) and concentrations of As higher than national regulation limits (>17 mg/Kg) at all sites other than one upstream, agricultural-dominated tributary in the dry season. These 'hotspots' are characterised by high inputs of organic matter (e.g. manure fertiliser and urban wastewater), which influences elemental mobility in the particulate and dissolved phases, and are potentially significant sources of pollution downstream. In addition, in the marine and fresh water mixing zone, salinity effects metal complexation with organic matter increasing metals in the particulate phase. Our calculations indicate that the delta is currently acting as a pollutant sink (as determined by high levels of pollutant deposition ∼50%). However, increased in-washing of pollutants and future projected increases in monsoon intensity, saline intrusion, and human activity could shift the delta to become a source of toxic metals. We show the importance of monitoring environmental parameters (primarily dissolved organic matter and salinity) in the RRD to assess the risk of transport and accumulation of toxic metals in the delta sediments, which can lead to net-increases in anthropogenic pollution in the coastal zone and the incorporation of toxic elements in the food chain.

Human practices behind the aquatic and terrestrial ecological decoupling to climate change in the tropical Andes

Anthropogenic climate change and landscape alteration are two of the most important threats to the terrestrial and aquatic ecosystems of the tropical Americas, thus jeopardizing water and soil resources for millions of people in the Andean nations. Understanding how aquatic ecosystems will respond to anthropogenic stressors and accelerated warming requires shifting from short-term and static to long-term, dynamic characterizations of human-terrestrial-aquatic relationships. Here we use sediment records from Lake Llaviucu, a tropical mountain Andean lake long accessed by Indigenous and post-European societies, and hypothesize that under natural historical conditions (i.e., low human pressure) vegetation and aquatic ecosystems' responses to change are coupled through indirect climate influences-that is, past climate-driven vegetation changes dictated limnological trajectories. We used a multi-proxy paleoecological approach including drivers of terrestrial vegetation change (pollen), soil erosion (Titanium), human activity (agropastoralism indicators), and aquatic responses (diatoms) to estimate assemblage-wide rates of change and model their synchronous and asynchronous (lagged) relationships using Generalized Additive Models. Assemblage-wide rate of change results showed that between ca. 3000 and 400 calibrated years before present (cal years BP) terrestrial vegetation, agropastoralism and diatoms fluctuated along their mean regimes of rate of change without consistent periods of synchronous rapid change. In contrast, positive lagged relationships (i.e., asynchrony) between climate-driven terrestrial pollen changes and diatom responses (i.e., asynchrony) were in operation until ca. 750 cal years BP. Thereafter, positive lagged relationships between agropastoralism and diatom rates of changes dictated the lake trajectory, reflecting the primary control of human practices over the aquatic ecosystem prior European occupation. We interpret that shifts in Indigenous practices (e.g., valley terracing) curtailed nutrient inputs into the lake decoupling the links between climate-driven vegetation changes and the aquatic community. Our results demonstrate how rates of change of anthropogenic and climatic influences can guide dynamic ecological baselines for managing water ecosystem services in the Andes.

Nitrous Oxide in Treatment Resistant Major Depression: Should We Laugh About It?

Introduction

Nitrous oxide (NO), also known as “laughing gas” is a colorless gas used as an anesthetic, a propellant in some foods, an engine performance enhancer and a recreational drug. When inhaled, it is known to provoke a rapid feeling of euphoria or excitement for a short period of time, dissociative phenomena and sometimes laughter. As its fellow anesthetic agent and NMDA-receptor antagonist, ketamine, NO is being studied for its possible therapeutic profile in treatment resistant major depression (TRMD).

Objectives

TRMD is a serious illness, that urges for effective alternative treatments. In that regard, we explored the recent studies conducted in these patients, using NO in different dosages when compared to placebo.

Methods

The authors revised the published literature about this topic, selecting relevant articles with the topic words: “Depression”, “Treatment Resistant Major Depression” and “Nitrous Oxide” in scientific data base.

Results

Since 2018, at least two randomized clinical trials have demonstrated that NO has considerable antidepressant effects in TRMD, when compared to placebo. Investigators noted that these positive effects where maintained at least for two weeks after a single 1-hour inhalation. In a more recent study, scientists compared different NO concentrations (25% vs. 50%) concluding that the 25% concentration had similar efficacy with a lower risk of adverse effects.

Conclusions

There appears to be encouraging results when treating patients with TRMD with NO in a 25% concentration. Nonetheless, there is need for further investigation, namely through studies that compare NO with other valid TRMD treatments and not only versus placebo.

Disclosure

No significant relationships.

Mental Health Refugees - Difficulties from the country of origin to the receiving country – A review

Introduction

The most recent global refugee figures are staggering, with over 82.4 million people forcibly displaced as a result of persecution, conflict, violence, human rights violations. However, little is known about their long-term mental health.

Objectives

This review aimed to assess prevalence of mental disorders and to identify the main factors associated with the development of mental disorders among refugees.

Methods

We searched MEDLINE databases using the key terms “refugees” and “global mental health” without language or date restriction. Articles were considered for inclusion in the review if they comprised a population of refugees. Three studies were identified.

Results

Our review showed a great heterogeneity in the prevalence of mental disorders that affect migrants showing an overall prevalence of 20% of these pathologies among them. War-related factors are more associated with Post Traumatic Stress Disorder and post-migration-related factors (acculturation, economic uncertainty and ethnic discrimination) are more associated with mood, anxiety and substance use disorders.

Conclusions

Existing evidence suggests that mental disorders tend to be highly prevalent in refugees many years after resettlement. The increased risk is not only caused by the past adversities in the country of origin but also by the post-migration-related factors. Thus, there is a need for more consistent and rigorous research from a methodological point of view on the mental health of refugees, allowing to find measures to protect and promote their mental health.

Disclosure

No significant relationships.

The impact of SARS-CoV-2 pandemic on suicidal ideation admissions: a single adolescent and young adult psychiatry center experience

Introduction

The COVID-19 pandemic and the lockdown brought about a sense of fear and anxiety around the globe. This phenomenon led to both short and long term psychosocial and mental health implications for children and adolescents.

Objectives

To evaluate the effect of COVID-19 pandemic on hospital admissions for suicidal ideation in a Portuguese adolescent and young adult psychiatry service.

Methods

We conducted a single-center, retrospective study including adolescent and young adult patients (15-25 years old) admitted to our service with suicidal ideation within a year before and a year after the declaration date of SARS-CoV-2 disease as a pandemic. Patients were divided in two groups: Group A - patients admitted before the pandemic (March 11, 2019 and March 11, 2020) and Group B – patients admitted after the pandemic declaration (March 12, 2020 and March 12, 2021). The groups characteristics and outcomes were assessed and compared.

Results

A total of 647 admissions were assessed (Group A, n= 372 and Group B, n=275). Demographic characteristics were similar between groups. 75 patients (vs 25 patients) were admitted with suicidal ideation in the year before the pandemic. There was a lower proportion of patients admitted with suicidal ideation during the year after the pandemic year - OR 0.374 (95% CI 0.228-0.614, P<0.001).

Conclusions

Our study showed a decrease in admissions for suicidal ideation in this service in the year after the pandemic. More studies are needed to understand the factors that may justify this decline and evaluate the longer effects of this pandemic in mental health.

Disclosure

No significant relationships.

Treating Patients with Aripiprazol: A Safe Gamble?

Introduction

Aripiprazole (ARI) is an atypical antipsychotic drug with D2 partial agonist properties, usually prescribed to treat mood disorders (major depression or bipolar disorder) and schizophrenic disorder (schizophrenia or schizoaffective disorder). Dopamine receptor agonists, as is ARI, have been implicated in some cases of impulse-control problems, such as gambling disorder (GD), increased spending, hypersexuality and compulsive eating.

Objectives

Currently, it is hypothesized that aripiprazole may cause impulse-control problems because it can produce a hyperdopaminergic state in the mesolimbic pathway (reward system) through its predominant action on dopamine D3 receptors. We intend to do a non-systematic review of the scientific information regarding this subject.

Methods

The authors revised the published literature about this topic, selecting relevant articles, systematic reviews and case reports, with the topic words: “aripiprazol”, “gambling disorder” and “dopamine receptor” in scientific data base.

Results

Overall, a few cases of ARI-induced pathological gambling as well as ARI-induced hypersexuality have been reported. In one study it was verified that comorbid psychiatric and substance use disorders were common among those who have experienced GD or worsened GD after beginning ARI treatment. In another study, it was verified that the group of patients who reported this alleged side-effect were mostly young (mean age, 33.6 years), mostly men (88.2%) and most lived alone.

Conclusions

Attributing to dopamine agonists the only factor that can explain the onset of GD is simplistic and dangerous. Many other potential risk factors, including individual vulnerability factors (temperament, genetics) as well as environmental factors, must be considered.

Disclosure

No significant relationships.

River connectivity and climate behind the long-term evolution of tropical American floodplain lakes

This study presents the long-term evolution of two floodplains lakes (San Juana and Barbacoas) of the Magdalena River in Colombia with varying degree of connectivity to the River and with different responses to climate events (i.e., extreme floods and droughts). Historical limnological changes were identified through a multiproxy-based reconstruction including diatoms, sedimentation, and sediment geochemistry, while historical climatic changes were derived from the application of the Standardised Precipitation-Evapotranspiration Index. The main gradients in climatic and limnological change were assessed via multivariate analysis and generalized additive models. The reconstruction of the more isolated San Juana Lake spanned the last c. 500 years. Between c. 1,620 and 1,750 CE, riverine-flooded conditions prevailed as indicated by high detrital input, reductive conditions, and dominance of planktonic diatoms. Since the early 1800s, the riverine meander became disconnected, conveying into a marsh-like environment rich in aerophil diatoms and organic matter. The current lake was then formed around the mid-1960s with a diverse lake diatom flora including benthic and planktonic diatoms, and more oxygenated waters under a gradual increase in sedimentation and nutrients. The reconstruction for Barbacoas Lake, a waterbody directly connected to the Magdalena River, spanned the last 60 years and showed alternating riverine-wetland-lake conditions in response to varying ENSO conditions. Wet periods were dominated by planktonic and benthic diatoms, while aerophil diatom species prevailed during dry periods; during the two intense ENSO periods of 1987 and 1992, the lake almost desiccated and sedimentation rates spiked. A gradual increase in sedimentation rates post-2000 suggests that other factors rather than climate are also influencing sediment deposition in the lake. We propose that hydrological connectivity to the Magdalena River is a main factor controlling lake long-term responses to human pressures, where highly connected lakes respond more acutely to ENSO events while isolated lakes are more sensitive to local land-use changes.

Hydro-climatic changes of wetlandscapes across the world

Assessments of ecosystem service and function losses of wetlandscapes (i.e., wetlands and their hydrological catchments) suffer from knowledge gaps regarding impacts of ongoing hydro-climatic change. This study investigates hydro-climatic changes during 1976-2015 in 25 wetlandscapes distributed across the world's tropical, arid, temperate and cold climate zones. Results show that the wetlandscapes were subject to precipitation (P) and temperature (T) changes consistent with mean changes over the world's land area. However, arid and cold wetlandscapes experienced higher T increases than their respective climate zone. Also, average P decreased in arid and cold wetlandscapes, contrarily to P of arid and cold climate zones, suggesting that these wetlandscapes are located in regions of elevated climate pressures. For most wetlandscapes with available runoff (R) data, the decreases were larger in R than in P, which was attributed to aggravation of climate change impacts by enhanced evapotranspiration losses, e.g. caused by land-use changes.

Freshwater Testate Amoebae (Arcellinida) Response to Eutrophication as Revealed by Test Size and Shape Indices

We review the potential for applying traits-based approaches to freshwater testate amoeba, a diverse protist group that are abundant in lakes and are valuable ecological indicators. We investigated the efficacy of geometric morphometric analysis to define Arcellinida test size and shape indices that could summarize freshwater testate amoeba community dynamics along a temporal gradient of eutrophication in Loch Leven, Scotland (United Kingdom). A cluster analysis of test size and shape indices yielded three clusters, each dominated by a single shape: elongate, spherical and ovoid. When plotted stratigraphically, we observed increases in spherical tests, decreases in elongate tests and shrinking of test size coeval with eutrophication in Loch Leven. Decreases in the elongate cluster may reflect benthic conditions with reduced oxygen levels, while increases in the spherical cluster are likely associated with an expanding macrophyte community that promoted pelagic and epibiotic life habits. Shrinking of test size may be a stress response to eutrophication and/or warming temperatures. Tracking community dynamics using test size and shape indices was found to be as effective as using species-based approaches to summarize key palaeolimnological changes, with the added benefits of being free from taxonomic bias and error. The approach thus shows significant potential for future studies of aquatic community change in nutrient impacted lakes.

A century of limnological evolution and interactive threats in the Panama Canal: Long-term assessments from a shallow basin

Large tropical river dam projects are expected to accelerate over the forthcoming decades to satisfy growing demand for energy, irrigation and flood control. When tropical rivers are dammed the immediate impacts are relatively well studied, but the long-term (decades-centuries) consequences of impoundment remain poorly known. We combined historical records of water quality, river flow and climate with a multi-proxy (macrofossils, diatoms, biomarkers and trace elements) palaeoecological approach to reconstruct the limnological evolution of a shallow basin in Gatun Lake (Panama Canal, Panama) and assess the effects of multiple linked factors (river damming, forest flooding, deforestation, invasive species, pollution and hydro-climate) on the study area. Results show that a century after dam construction, species invasion, deforestation and salt intrusions have forced a gradual change in the study basin from a swamp-type environment towards a more saline lake-governed system of benthic-littoral production likely associated with the expansion of macrophyte stands. Hydrology still remains the most important long-term (decades) structural factor stimulating salinity intrusions, primary productivity, deposition of minerals, and reduction of water transparency during wet periods. During dry periods, physical-chemical conditions are in turn linked to clear water and aerobic conditions while nutrients shift to available forms for the aquatic biota in the detrital-rich reductive sediments. Our study suggests that to preserve the natural riverine system functioning of this area of the Panama Canal, management activities must address long-term ecosystem structural drivers such as river flow, runoff patterns and physical-chemical conditions.

Utilisation of a mix of powdered oils as fat supplement in nursery- and growing-pig diets

Two experiments were conducted to challenge nursery and growing pigs to increased levels of dietary fat (5–10% as fed), using a crystallised powdered oil mix (CPOM), produced by a modified freeze-drying process. Growth performance of nursery pigs was determined and a digestibility trial was also conducted with growing pigs (Experiment 2). The CPOM was compared, at similar levels of lipid inclusion (10% total lipids), with other fat sources commonly used in swine diet, namely soybean oil (SBO) and hydrogenated palm oil. For the growth assay (Experiment 1), the CPOM was prepared and added at different levels (0%, 2.6% and 3.8%) commonly used in commercial diets (Phase 1–4 diets). Seventy-five weaning pigs (28 days of age) were housed in 15 pens (5 pigs per pen) and randomly assigned into the three dietary treatments until 70 days of age. Growth performance and feed utilisation were compared weekly among experimental groups. The use of CPOM improved average daily gain (~60%), and increased average daily feed intake by 40% and 50% at the 2.6% and 3.8% CPOM levels respectively. In the digestibility trial (Experiment 2), pigs fed with 5% incorporation of CPOM (10% of total lipid content) had digestibility of energy and ether extract similar to those fed the SBO-supplemented diet, although the SBO diet had a significantly greater polyunsaturated fatty acid concentration. The powdered crystallisation process of the CPOM fat allowed an equivalent digestibility of this fat source with more saturated fatty acids, and the physical-property effect of this processed oil source on apparent total-tract digestibility should be further studied.

SEOM clinical guideline on unknown primary cancer (2017)

Cancer of unknown primary site is a histologically confirmed cancer that manifests in advanced stage, with no identifiable primary site following standard diagnostic procedures. Patients are initially categorized based on the findings of the initial biopsy: adenocarcinoma, squamous-cell carcinoma, neuroendocrine carcinoma, and poorly differentiated carcinoma. Appropriate patient management requires understanding several clinical and pathological features that aid in identifying several subsets of patients with more responsive tumors.

New insight into the environmental impact of two imidazolium ionic liquids. Effects on seed germination and soil microbial activity

The next generation of ionic liquids must be synthetized taking into account structures that guarantee the suitable properties for a defined application as well as ecological data. Thus, searching of the right methodologies to know, quickly and efficiently, the ecological effects of these compounds is a preliminary task. The effects of two imidazolium based ionic liquids with different anions, 1-butyl-3-methylimidazolium tetrafluoroborate, [C₄C₁Im][BF₄], and 1-propyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C₃C₁Im][NTf₂], on seedling emergence of six tree species and on the microbial behaviour of two soils were determined in this work. Results showed that the highest doses of both ionic liquids caused the total inhibition of germination for almost all the species studied and that the seeds are more sensitive to the presence of these compounds than soil microbial activity. Nevertheless, signals of stress and death are observed from the results of heat released by microorganisms after the addition of the highest doses of both ionic liquids. The novelty of this work resides in the enlargement of knowledge of toxicity of ILs on complex organisms such as arboreal species and microbial activity of soils studied for the first time through a microcalorimetric technique.

How gamma-rays and electron-beam irradiation would affect the antimicrobial activity of differently processed wild mushroom extracts?

AIMS

The effects of irradiation (gamma-rays and electron-beams), up to 10 kGy, in the antimicrobial activity of mushroom species (Boletus edulis, Hydnum repandum, Macrolepiota procera and Russula delica) differently processed (fresh, dried, freeze) were evaluated.

METHODS AND RESULTS

Clinical isolates with different resistance profiles from hospitalized patients in Local Health Unit of Mirandela, Northeast of Portugal, were used as target micro-organisms. The mushrooms antimicrobial activity did not suffer significant changes that might compromise applying irradiation as a possible mushroom conservation technology.

CONCLUSIONS

Two kGy dose (independently of using gamma-rays or electron-beams) seemed to be the most suitable choice to irradiate mushrooms.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides important results in antimicrobial activity of extracts prepared from irradiated mushroom species.

Long-term thermal stabilities of ammonium ionic liquids designed as potential absorbents of ammonia

Searching for potential absorbents in working pairs with NH₃, a series of new ammonium ionic liquids related to choline, were designed and synthesized. Their thermal stabilities in both non-isothermal and isothermal conditions were studied.

Interferon Gamma Response to Combinations 38 kDa/CFP-10, 38 kDa/MPT-64, ESAT-6/MPT-64 and ESAT-6/CFP-10, Each Related to a Single Recombinant Protein ofMycobacterium tuberculosisin Individuals from Tuberculosis Endemic Areas

Several antigens of Mycobacterium tuberculosis have been identified and specificity to one or multiple antigens could determine the distinction between protective and pathogenic host reaction. Therefore T cell immune response to combinations 38 kDa/CFP-10, 38 kDa/MPT-64, ESAT-6/MPT-64 and ESAT-6/CFP-10 (each related to a single protein of Mycobacterium tuberculosis) in individuals from tuberculosis endemic areas have been examined. ELISA was used to detect IFN-gamma production in PBMC priming with single proteins and combinations in a panel of 105 individuals: 38 tuberculosis patients (6 untreated and 32 treated) and 67 healthy controls with tuberculin skin test positive or negative (TST). Brazilian TB patients highly recognized ESAT-6 (66%), but combinations improved response in the following order: ESAT-6/MPT-64 (89%) > ESAT-6/CFP-10 (73%) > 38 kDa/CFP-10 (70%), the last combination showing the highest specificity (TST(/) = 42% and TST(-) = 83%). Average IFN-gamma production in TB patients was signifi-cantly higher for 38 kDa/CFP-10 (P = 0.012) and 38 kDa/MPT-64 (P <0.035), when compared to single antigens. None of the combinations was able to discriminate TB patients from TST(+) controls; however, 38 kDa/CFP-10 displayed a borderline significance (P = 0.053). Similar to the ESAT-6/CFP-10 combination, IFN-gamma response to 38 kDa/CFP-10 showed an increased tendency in treated patients, although not signifi-cant (P = 0.16). We demonstrated for the first time that 38 kDa/CFP-10 had prediction sensitivity for TB patients similar to the ESAT-6/CFP-10 combination and also significant response improvement related to the single proteins with more selective reactivity among TST-positive individuals, which could be of potential interest for diagnostic evaluation for tuberculosis infection.

Transportable distance measurement system based on superheterodyne interferometry using two phase-locked frequency-doubled Nd:YAG lasers

We describe a transportable distance measurement system based on synthetic wavelength interferometry. Two frequency-doubled Nd:yttrium aluminum garnet lasers at 532 nm are used to generate a synthetic wavelength of approximately 2.5 cm. A nonpolarizing interferometric system has been set up to eliminate polarization cross-talk issue. A superheterodyne detection was performed to measure the synthetic phase and to determine absolute distances. The capability to achieve fringe interpolation of 2pi/5600 has been demonstrated and an agreement in distance measurement at the 4 microm level has been achieved, compared to an optical interferometric 3 m long displacement bench.

[Wavefront-guided and wavefront-optimised LASEK--comparison of clinical results]

PURPOSE

The aim of this study was to compare refractive outcomes and wavefront results in eyes undergoing wavefront-optimised and wavefront-guided LASEK.

METHODS

In this contralateral eye study wavefront-guided LASEK and wavefront-optimised LASEK have been carried out on 30 eyes each. Preoperatively, 1 month, 3 months and 6 months after surgery a full ophthalmological examination was carried out. Preoperatively and 6 months postoperatively additional wavefront measurement have been carried out on all patients.

RESULTS

The mean preoperative refraction in the wavefront-guided group was -4.41 D (SD 1.38 D) and in the wavefront-optimised group -4.62 D (SD 1.86 D). The postoperative refraction was very good in both groups (wavefront-guided -0.06 D, SD 0.18 D; wavefront-optimised -0.03 D, SD 0.21 D). In both groups RMS of higher orders were increased slightly (wavefront-guided from 0.26 to 0.31 microm, wavefront-optimised from 0.27 to 0.32 microm) and also spherical aberrations increased slightly (wavefront-guided from 0.18 to 0.23 microm, wavefront-optimised from 0.16 to 0.21 microm).

CONCLUSIONS

The refractive results with the Concept System 500 in patients with preoperatively low amounts of higher order aberrations after wavefront-guided and wavefront-optimised LASEK are comparable. As good wavefront measurements need a lot of experience and take a lot of time, there is no advantage of wavefront-guided ablation in patients with low preoperative aberrations.

GSTP1 and MTHFR polymorphisms are related with toxicity in breast cancer adjuvant anthracycline-based treatment

We have analyzed several members of drug-metabolizing enzymes (DMEs) and other polymorphisms in genes implicated in tumor aggressivity regarding possible links between specific genetic variability in systemic drug bioavailability and toxicity in breast cancer patients treated with adjuvant anthracycline-based treatment. PCR-RFLP and sequencing analyses technique were used for evaluating fourteen previously identified polymorphisms in 94 patients. GSTP1A>G and MTHFR 1298A>C genotypes remained as significant predictors in a multivariate logistic regression analysis. GSTP1 polymorphism was linked to haematological GIII-IV toxicity (P = 0.044, HR= 6.4, 95% CI = 1.05 to 39. Increased and significant HR was obtained for MTHFR-1298 AC+CC group when non-haematological toxicities GIII-IV toxicities were evaluated (HR = 24; 95% CI = 2.3 to 254), P = 0.008. Our results suggest that GSTP1 and MTHFR genotypes may be consider relevant and independent factors of toxicity in adjuvant anthracycline-based treatment of breast cancer.

Cell proliferation and interferon-gamma response to recombinant MBP-3, NarL, MT-10.3, and 16 kDa Mycobacterium tuberculosis antigens in Brazilian tuberculosis patients

Human pulmonary tuberculosis (TB) is a worldwide public health problem. In resistant individuals, control of the infection mainly requires development of a Th1 cell immune response with production of cytokines, of which interferon-gamma (IFN-gamma)plays an important role. Several antigens from Mycobacterium tuberculosis complex has been described for use in vaccine development or for diagnostic purposes, however little evaluation has been done in endemic area for TB. The proliferative and IFN-gamma human T cell immune responses, to four recombinant proteins (MBP-3, NarL, MT-10.3, 16 kDa) and PPD, of 38 Brazilian TB patients (6 untreated and 32 treated) and 67 controls (38 positive and 29 negative tuberculin skin test - TST) were compared. The highest reactivity mean rate was obtained with PPD followed by 16 kDa in TB patients. While most of the patients (87%) and controls (> 64%) respond to the PPD, 16 kDa was more specifically recognized (> 21%) although less sensitive (54%). When TB patients were divided according to treatment status, opposite to PPD, higher average level of IFN-gamma was induced by 16 kDa in untreated (505 pg/ml) compared to treated TB patients and TST+ (269.8 pg/ml x 221.6 pg/ml, respectively), although the difference was not significant. These data show that in contrast with the other recombinant proteins, the stimulatory potency of 16 kDa to induce proliferative and INF-gamma response was more effective and is more recognized by active TB untreated patients, eliciting in control individuals a more selective immune response than PPD.

Structure-based assessment of BRCA1 and BRCA2 mutations in a small Spanish population

Breast cancer is the most frequent cancer type among women in the world. There is abundant evidence, that alterations in the breast cancer susceptibility genes, BRCA1 and BRCA2, are present in a large proportion of families with multiple cases of breast and ovarian cancer. Our aim was to better understand the molecular and structural insights associated with the most frequent alterations, found in the BRCA1 and BRCA2 genes, within our patients. We analyzed 50 breast cancer cases. Of those, 24% were found to carry deleterious mutations, and up to 10 rare variants of unknown significance were detected. The frequency of polymorphic changes was considerably different between genes, BRCA1 (55%) and BRCA2 (19.4%). By looking at the protein level, the changes observed within the BRCA1 and BRCA2 genes could affect not only the nucleic location of the protein but also disrupt the folding and, therefore, the tumor suppressor function.

MCNP simulation to optimise in-pile and shielding parts of the Portuguese SANS instrument

A Small Angle Neutron Scattering instrument is being installed at one end of the tangential beam tube of the Portuguese Research Reactor. The instrument is fed using a neutron scatterer positioned in the middle of the beam tube. The scatterer consists of circulating H2O contained in a hollow disc of Al. The in-pile shielding components and the shielding installed around the neutron selector have been the object of an MCNP simulation study. The quantities calculated were the neutron and gamma-ray fluxes in different positions, the energy deposited in the material by the neutron and gamma-ray fields, the material activation resulting from the neutron field and radiation doses at the exit wall of the shutter and around the shielding. The MCNP results are presented and compared with results of an analytical approach and with experimental data collected after installation.

Towards the enhancement of the photon/neutron discrimination of C6D6 detectors in the range from 1 to 10 MeV using liquid scintillator materials doped with high-Z elements

The study on the behaviour of deuterated benzene detectors in the energy range from 1 to 10 MeV has been carried out. It is shown that the photon-to-neutron discrimination, attained with standard detectors, can be improved by doping the C6D6 liquid scintillator with high-Z elements. The motivation for doping the organic scintillator stems from the fact that they should increase the gamma detection efficiencies with no significant changes in the abilities to detect neutrons. The results obtained using the MCNP and EGS4 codes show that increasing the fraction of high-Z elements: (a) the energy deposited in the medium by photons increases, (b) the energy deposited by neutrons decreases and (c) the rate of detection of photon/neutron is enhanced. Owing to their low sensitivity to neutrons and the enhanced gamma detection efficiency, these detectors could be ideally used to carry out studies in mixed neutron-photon fields in the energy range considered and to assess the gamma backgrounds in noisy neutron environments.