Methylmercury in environmental compartments of a hydroelectric reservoir in the Western Amazon, Brazil.

Damming rivers to generate electricity creates a lentic environment that favors methylmercury (MeHg) formation. Reservoirs in the Amazon are critical environments for MeHg formation, considering its old soils and the use of Hg in gold mining in the region. The objective of this study was to evaluate MeHg accumulation in three environmental compartments (aquatic macrophytes, suspended particulate matter (SPM) and sediment) of the Samuel reservoir (Western Amazon, Brazil), during the low water, ebb and high water hydrological periods, characterizing the dry season, the end of the rainy season and the rainy season, respectively.

Intestinal toxicity evaluation of long-circulating and pH-sensitive liposomes loaded with cisplatin.

Cisplatin (CDDP) is a chemotherapeutic agent widely used in several anticancer protocols for instance head and neck, testicle, ovarian, lung and peritoneal carcinomatosis. According to the literature, the use of CDDP is associated with several side effects; among them, we highlighted the mucositis. CDDP, when administered by IP, promoted significant intestinal epithelium alterations in an experimental model.

Evaluation of antitumor activity and cardiac toxicity of a bone-targeted ph-sensitive liposomal formulation in a bone metastasis tumor model in mice.

Chemotherapy for bone tumors is a major challenge because of the inability of therapeutics to penetrate dense bone mineral. We hypothesize that a nanostructured formulation with high affinity for bone could deliver drug to the tumor while minimizing off-target toxicity. Here, we evaluated the efficacy and toxicity of a novel bone-targeted, pH-sensitive liposomal formulation containing doxorubicin in an animal model of bone metastasis.

Evolving role of radiolabeled particles in detecting infection and inflammation, preliminary data with 99mTc-phytate in rats.

Purpose: The aim of this study was to evaluate the ability of phytate radiolabeled with technetium-99m (Tc-phytate) to identify inflammatory processes.

Materials And Methods: Radiolabeling efficiency analyses were carried out by thin-layer chromatography on silica gel strips, yielding a radiochemical purity of 92%. In addition, the partition coefficient of Tc-phytate, obtained in a mixture of n-octanol/water (1 : 1), showed hydrophilic features of the radiopharmaceutical.

Evaluation of different methods of cryopreservation of Ehrlich tumor cells.

Background: The Ehrlich Ascitic Carcinoma (EAC) is an experimental transplantable neoplasm that develops in several species of mice. The maintenance of the tumor occurs in vivo. Thus, freezing the cells would reduce the number of passages between animals, ensuring genetic stability and storage for longs period of experimentation.

Pretreatment and Treatment With L-Arginine Attenuate Weight Loss and Bacterial Translocation in Dextran Sulfate Sodium Colitis.

Background: Imbalances in a variety of factors, including genetics, intestinal flora, and mucosal immunity, can contribute to the development of ulcerative colitis and its side effects. This study evaluated the effects of pretreatment or treatment with arginine by oral administration on intestinal permeability, bacterial translocation (BT), and mucosal intestinal damage due to colitis.

Methods: C57BL/6 mice were distributed into 4 groups: standard diet and water (C: control group), standard diet and dextran sodium sulfate (DSS) solution (Col: colitis group), 2% L-arginine supplementation for 7 days prior to DSS administration and during disease induction (PT: pretreated group), and 2% L-arginine supplementation during disease induction (T: treated group).

Synthesis of nitroaromatic compounds as potential anticancer agents.

Twenty-seven nitrated and non-nitrated compounds have been synthesized and tested for their growth inhibitory activity on three human cancer cells lines. Fourteen compounds were able to inhibit more than 50% of the growth of at least one of the cancer cell lines and five compounds exhibited high antiproliferative activity on human cancer cell lines (IC50 < 8.5 μM).

Canine low-grade intra-orbital myxosarcoma: case report.

Objective: The aim of this study was to evaluate important clinical, morphological, histopathological, histochemical, and immunohistochemical characteristics in order to establish the diagnosis and prognosis of a low-grade intra-orbital myxosarcoma.

Animal Studied: A mongrel dog presented a 2-year history of a neoplastic mass behind the right eye.

Results: The neoplasm presented a mesenchymal spindle and stellate cell proliferation with an abundant myxoid matrix, moderate anisocariosis, and a low mitotic index.

Combination therapy with carboplatin and thalidomide suppresses tumor growth and metastasis in 4T1 murine breast cancer model.

Carboplatin, efficient cytostatics for cancer therapy, could induce apoptosis and inhibit the growth of vascular endothelium in several tumor cell lines and xenograft models. It has been suggested that the antitumor effect of chemotherapy could be increased by combining it with an antiangiogenesis agent in anticancer strategy. The present study explored the potential to increase the antitumor effect of carboplatin by combining it with thalidomide in mouse 4T1 breast cancer models, and the underlining mechanism was investigated.

Long-circulating, pH-sensitive liposomes versus long-circulating, non-pH-sensitive liposomes as a delivery system for tumor identification.

Bombesin (BBN) is a tetradecapeptide that binds specifically to gastrin-releasing peptide receptors in humans. Several forms of cancer, including lung, prostate, breast, and colon over-express receptors for bombesin-like peptides. Therefore, radiolabeled bombesin analogs might be useful for tumor identification.

Carboplatin delays mammary cancer 4T1 growth in mice.

Carboplatin is commonly used to treat a variety of tumors. We investigated the effects of carboplatin (100mg/kg) in the development and metastatic dissemination of the 4T1 mice mammary carcinoma. Carboplatin was able to reduce tumor volume and the number of lung metastases in 50% compared to the control animals.

Encapsulation of cisplatin in long-circulating and pH-sensitive liposomes improves its antitumor effect and reduces acute toxicity.

Cisplatin (CDDP) is one of the most effective and potent anticancer drugs used as first-line chemotherapy against several solid tumors. However, the severe side effects and its tendency to provoke chemoresistance often limit CDDP therapy. To avoid these inconveniences, the present study's research group developed long-circulating and pH-sensitive liposomes containing CDDP (SpHL-CDDP).

Antitumor effectiveness and toxicity of cisplatin-loaded long-circulating and pH-sensitive liposomes against Ehrlich ascitic tumor.

Cisplatin (CDDP) is one of the most active cytotoxic agents commonly used in the treatment of peritoneal carcinomatosis. The disadvantages of its clinical use are systemic side-effects, such as nephrotoxicity and myelotoxicity. Long-circulating and pH-sensitive liposomes containing CDDP (SpHL-CDDP) were developed by our research group aiming to promote the release of CDDP near the tumor as well as decreasing toxicity.

Antitumoral activity and toxicity of PEG-coated and PEG-folate-coated pH-sensitive liposomes containing ¹⁵⁹Gd-DTPA-BMA in Ehrlich tumor bearing mice.

In the present study, PEG-coated pH-sensitive and PEG-folate-coated pH-sensitive liposomes containing the ¹⁵⁹Gd-DTPA-BMA were prepared and radiolabeled through neutron activation technique, aiming to study the in vivo antitumoral activity and toxicity on mice bearing a previously-developed solid Ehrlich tumor. The treatment efficacy was verified through tumoral volume increase and histomorphometry studies. The toxicity of formulations was investigated through animal weight variations, as well as hematological and biochemical tests.

Total mercury in sediments and in Brazilian Ariidae catfish from two estuaries under different anthropogenic influence.

Santos-São Vicente estuary, located in São Paulo State, Brazil, has a history of contamination by inorganic chemicals such as mercury (Hg). In the 1980s the Cubatão was considered one of the most polluted sites in the world as a consequence of the intense industrial activities located in the city close to the estuary. To provide data and evaluate the local biota, total mercury (THg) contents were determined in sediments and in fish, Cathorops spixii, from different areas of the Santos-São Vicente estuary.

Total mercury, organic mercury and selenium in liver and kidney of a South American coastal dolphin.

Selenium and total and organic mercury were determined in the liver and kidney of franciscana dolphin (Pontoporia blainvillei) incidentally caught in fishing nets along two Brazilian coastal areas (southeast and south). Regional differences in the concentrations of these contaminants were observed in P. blainvillei.

Ecological and biological determinants of trace elements accumulation in liver and kidney of Pontoporia blainvillei.

The present work tested whether ecological and biological variables have an influence on the assimilation of trace elements by the tissues of a cetacean from the Western South Atlantic Ocean. No significant differences were observed in the concentrations for both sexes. As individuals from the two sampling areas belong to distinct genetic and morphological populations, animals of similar body length were older on the southeastern than on the southern coast.