http://hdl.handle.net/10400.18/68 2013-05-21T00:08:09Z 2013-05-21T00:08:09Z Menezes, Carina Alverca, Elsa Dias, Elsa Sam-Bento, Filomena Paulino, Sérgio Pereira, Paulo http://hdl.handle.net/10400.18/1140 2013-01-02T17:26:36Z 2010-11-01T00:00:00Z

Title: Cytotoxic and morphological effects of microcystin-LR in in vitro models - a comparision between HepG2, Vero-E6, MDCK and CaCo-2 cell lines Authors: Menezes, Carina; Alverca, Elsa; Dias, Elsa; Sam-Bento, Filomena; Paulino, Sérgio; Pereira, Paulo Abstract: Microcystin-LR (MCLR), a potent hepatotoxin, is transported selectively into the cells throught specific membrane polypeptides mostly present in the liver. These transporters are also expressed in the brain, kidneys and intestine, although the toxicity of MCLR in these cell types is still poorly understood. In this study, morphological, ultrastructural and biochemical analyses were performed in hepatic, renal and intestinal cell lines in order to evaluate the toxicity of MCLR obtained from semi-purified cyanobacterial extracts. Our results show that after 24h of exposure, MCLR induces the viability decrease of all cell lines, in a concentration-dependent manner. HepG2 cells are the most susceptible, followed by Vero, MDCK and CaCo-2. Ultrastructural analyses show that subcytotoxic concentrations of MCLR induce the formation of large cytoplasmic vacuoles, particularly in the HepG2 cell line. Immunofluorescence microscopy reveals that these vacuoles are enriched in LC3B protein, suggesting autophagy as an early cellular response of HepG2 and Vero cells to MCLR. At cytotoxic MCLR concentrations, lysossomal dysfunction in both cell lines occurs prior to mitochondrial disruption, as demonstrated by the specific labeling with Acridine Orange and Rhodamine-123. This suggests that besides mitochondria, lysossomes may also be an MCLR-early target. Immunolocalization and western blot analysis of the endoplasmic reticulum anti-apoptotic protein GRP94 show distinct MCLR-induced effects in Vero and HepG2 cells: re-localization of GRP94 within Vero cells and decrease of GRP94 expression in the HepG2 cell line. These results demonstrate that all the studied cell lines are susceptible to MCLR although with cell type specificity and differential organelle targeting.

2010-11-01T00:00:00Z Cano, Manuela Nogueira, Susana Papoila, Ana Luísa Aguiar, Fátima Martins, Pedro Marques, João Caires, Iolanda Martins, José Pedro, Catarina Paixão, Paulo Rosado-Pinto, José Leiria-Pinto, Paula Aelenei, Daniel Mendes, Ana Teixeira, João Paulo Proença, Carmo Neuparth, Nuno http://hdl.handle.net/10400.18/1107 2012-11-01T02:34:16Z 2012-08-01T00:00:00Z

Title: Indoor Air Quality in Portuguese Day Care Centers - ENVIRH Project Authors: Cano, Manuela; Nogueira, Susana; Papoila, Ana Luísa; Aguiar, Fátima; Martins, Pedro; Marques, João; Caires, Iolanda; Martins, José; Pedro, Catarina; Paixão, Paulo; Rosado-Pinto, José; Leiria-Pinto, Paula; Aelenei, Daniel; Mendes, Ana; Teixeira, João Paulo; Proença, Carmo; Neuparth, Nuno Abstract: This paper describes field measurements of indoor air quality (IAQ) parameters, performed in 19 Portuguese Children Day Care Centers (CDCC) during the springtime of 2011 and aims to characterize the indoor environment. The results demonstrate an association between carbon dioxide and bacterial concentrations, which in turn are affected by the number of children present in each classroom. Indoor PM10 concentrations were higher than outdoor levels (I/O ratio>1) and was also found statistically significant association between PM10 concentrations and the type of floor covering materials. These results provide evidence that IAQ is inadequate and, as a consequence, human source contaminants such as bacteria and carbon dioxide accumulate indoors. This study suggests that it is necessary to improve ventilation in order to achieve a healthier indoor environment.

2012-08-01T00:00:00Z Menezes, Carina Alverca, Elsa Dias, Elsa Paulino, Sérgio Sam-Bento, Filomena Pereira, Paulo http://hdl.handle.net/10400.18/1101 2012-10-31T02:34:23Z 2009-05-01T00:00:00Z

Title: Estudo comparativo da citotoxicidade e alterações citopatológicas induzidas pela microcistina-LR em linhas celulares renais e hepáticas (Vero e HepG2). Authors: Menezes, Carina; Alverca, Elsa; Dias, Elsa; Paulino, Sérgio; Sam-Bento, Filomena; Pereira, Paulo Abstract: Microcystin-LR (MCLR) is a potent hepatotoxin produced by freshwater cyanobacteria, being responsible for acute and chronic hazards to animal and human health. Despite the increasing recognition of its toxic effects, the cellular basis of MCLR-induced toxicity is still poorly understood. In this work, morphological, ultrastructural and biochemical (MTT and Neutral Red-NR) analyses were performed to evaluate the effects of a semi-purified MCLR-containing cyanobacterial extract on Vero and HepG2 cell lines. Our results showed that cell viability decayed markedly after 24h of exposure to toxin concentrations greater than 25μg.ml-1 in both cell lines. The ultrastructural analysis revealed that at subcytotoxic MCLR doses, cells presented large cytoplasmic vacuoles, which were more prominent in HepG2. These vacuoles showed to be enriched in the LC3 protein, suggesting that autophagy is an early cellular response to MCLR. At higher doses, the specific staining Acridine Orange (AO) and Rhodamine-123 (Rh-123), demonstrated that lysosome destabilization precedes mitochondrial dysfunction. Besides, MCLR seemed to induce a decrease in the expression of the anti-apoptotic endoplasmic reticulum protein Grp94, particularly evident in HepG2 cells. These results suggest that MCLR-induced cytotoxicity involves a considerable crosstalk among several organelles and that despite some cell-specific features, the general cellular basis underlying this toxicity is common to both Vero and HepG2 cells.

2009-05-01T00:00:00Z Cano, M. Azevedo, S. Aguiar, F. Almeida, G. Brás, C. Pinhal, H. Nogueira, A. Proença, M.C. http://hdl.handle.net/10400.18/830 2012-03-17T02:34:18Z 2011-10-01T00:00:00Z

Title: Preliminary results on indoor environmental quality in day care centers located in Lisbon Authors: Cano, M.; Azevedo, S.; Aguiar, F.; Almeida, G.; Brás, C.; Pinhal, H.; Nogueira, A.; Proença, M.C. Abstract: The growing concern about indoor air quality results from the knowledge that exposure to indoor air pollutants may be higher than the exposure to outdoor air pollutants and from the evidence that in most developed countries day care centers are places where children spend most of their time. How environmental factors affect children respiratory health is still controversial and unclear. This paper describes the results from field measurements of physical parameters, chemical and biological indoor contaminants, to investigate indoor environmental quality, in 70 classrooms of 10 Children Day Care Centers (CDCC), located in Lisbon. Objective The aim of this study is to gather information on indoor environment of CDCC in order to correlate it with both ventilation and children’s health. Material and Methods Chemical contaminants (carbon dioxide, carbon monoxide, formaldehyde, total volatile organic compounds and PM10), biological contaminants (bacteria, fungi and house-dust mites) and thermal comfort parameters were monitored. Formaldehyde was analyzed according to NIOSH 3500 method using a visible absorption spectrometry with air samples taken on impingers by active sampling. Total volatile organic compounds were analyzed by gas chromatography according to the ISO 16000, part 6, with air samples taken on Tenax TA sorbent by active sampling. Carbon monoxide and carbon dioxide measurements were made using a Photoacoustic Multi- Gas Monitor INNOVA. Samples of viable microorganisms were collected using a MAS-100 sampler with Malt Extract Agar plates, Trypticase Soy Agar and MacConkey agar as collecting media for fungi, total bacteria and gram-negative bacteria. Dust samples were collected on filters using a vacuum cleaner with a DustreamTM collector and determined using an ELISA test to quantify mite antigens. PM10 were collected using PTFE filters on Personal Environmental Monitors attached to personal pumps and the filters were analyzed gravimetrically for particle mass. Thermal comfort was evaluated according to the ISO 7730 International Standard using a 1213 Bruel & Kjaer analyzer. Results The reported preliminary results only represent a small part of a larger study under development in 20 CDCC located on Lisbon and Porto. The mean CO2 concentration indoors exceeded the recommended level of 1800 mg/m3 in 54% of the 70 studied rooms, with a maximum concentration of 5630 mg/m3 and an outdoor average of 839 mg/m3. The majority of the studied rooms had suspended particulate matter, TVOC’s and formaldehyde concentrations under the recommended limits. In 51% of the rooms the bacterial concentrations exceed 500 ufc/m3 (recommended limit), being also observed predominance gram-positive bacteria. In 50% of the studied rooms fungal concentrations were above 500 ufc/m3, however the mean outdoor concentration was 560 ufc/m3. Conclusion The preliminary results provide evidence that ventilation is insufficient, resulting in the accumulation of human source contaminants, such as bacteria and CO2. Taking into consideration that the results correspond to the Spring period, when occupants maintain windows and doors open, we expect worse results in the Winter period.

2011-10-01T00:00:00Z