Characterization of fungal communities in house dust samples collected from central Portugal-a preliminary survey.

House dust is a repository and concentrator of many chemical and biological agents including fungi. Considering that dust acts as a long-term reservoir of airborne fungi and that cumulative exposure is more relevant to potential health problems than single-day or short-term exposure, characterization of fungal communities in dust samples is of paramount importance. In the present study, the fungal composition of Portuguese house dust samples was determined. A total of 28 samples were obtained from vacuum cleaner deposits from households located in central Portugal. DNA was extracted from dust samples and fungal communities were analyzed using a culture-independent polymerase chain reaction (PCR)- denaturing gradient gel electrophoresis (DGGE) approach. Cultural analyses were also performed in order to identify the viable fungi species present in selected samples. Fungal diversity, reported as the number of operational taxonomic units (OTU), varied between 9 and 56 OTU. This analysis of viable fungi showed that Aspergillus was the most abundant genus, followed by Penicillium, Mucor, and Rhizomucor. Trichoderma, Chrysosporium, Fusarium, Rhizopus, and Stachybotrys were found in a limited number of houses. Our results demonstrated that dust is, in fact, home for a diverse and heterogeneous fungal community and that some of the species found are known allergic agents with severe negative impacts on human health.

Biological risk assessment: A challenge for occupational safety and health practitioners during the COVID-19 (SARS-CoV-2) pandemic.

BACKGROUND: The COVID-19 global pandemic brought several challenges to occupational safety and health practice. One of these is the need to (re)assess the occupational risks, particularly, biological risks. OBJECTIVE: The purpose of this work is to promote guidance to occupational safety and health practitioners when conducting a biological risk assessment in this context. METHODS: The main steps of the biological risk assessment are explained with some inputs regarding the novelty posed by SARS-CoV-2 and an example of a qualitative risk assessment method is presented. Also, its application to two different activities was exemplified. RESULTS: In both cases, the assessment considered that vulnerable workers were working from home or in medical leave. The results showed low or medium risk level for the assessed tasks. For medium risk level, additional controls are advised, such maintain social distancing, sanitize instruments/equipment before use, use proper and well-maintained PPE (when applicable), and promote awareness sessions to spread good practices at work. Employers must be aware of their obligations regarding biological risk assessment and OSH practitioners must be prepared to screen and link the abundance of scientific evidence generated following the outbreak, with the technical practice. CONCLUSIONS: This paper could be an important contribution to OSH practice since it highlights the need to (re)assess occupational risks, especially biological risk, to ensure a safe return to work, providing technical guidance.

Kinetics of radium-223 and its effects on survival, proliferation and DNA damage in lymph-node and bone metastatic prostate cancer cell lines.

BACKGROUND: Metastatic castration-resistant prostate cancer (mCRPC) is associated with a very unfavorable prognosis. At this advanced stage of the disease, there are several therapeutic strategies approved in recent times, being one of them Radium-223 dichloride (Radium-223). However, its mechanisms of action and the process that conducts to cell death are not fully understood. Given this, our main goal is to characterize the radiobiological effects induced by Radium-223 and to evaluate its kinetics on metastatic Prostate Cancer (mPCa) cells. MATERIALS AND METHODS: In vitro studies were conducted using two mPCa cell lines, the LNCaP and PC3, the first being derived from lymph node metastasis and the second from bone metastasis. Kinetic studies were conducted to access the capacity of these cell lines to uptake, retain and internalize the Radium-223. For the assessment of radiobiological effects, cells were first exposed to different doses of Radium-223 and the clonogenic assay was done to evaluate cell survival and to determine lethal doses (LD50). Then, the effects were also evaluated in terms of proliferation, oxidative stress, morphological changes and cell damage. RESULTS: Radium-223 is uptaken by mPCa cells and reaches the nucleus, where it is retained over time. Irradiation decreases cell survival and proliferation, with LNCaP cells (LD50 = 1.73mGy) being more radiosensitive than PC3 cells (LD50 = 4.20mGy). Irradiated cells showed morphological changes usually associated with apoptosis and a dose-dependent increase in DNA damage. Moreover, activation of cell cycle checkpoints occurs through ATM/CHK2 pathway, which is involved in cell cycle arrest and cell death. CONCLUSIONS: The cytotoxic and anti-proliferative effects on both cell lines showed that Radium-223 can decrease the aggressiveness of tumor cells by decreasing the cell survival and proliferation and, also, by increasing the DNA damage. The similar results observed in both cell lines indicated that Radium-223 may have the potential to be used as a therapeutic option also for mCRPC patients with lymph node metastasis. The activation of DNA Damage Response pathways allows the possibility to understand the importance of these checkpoints as targets for new combined therapies.