Effects of the food contaminant semicarbazide on testicular morphology of juvenile Wistar rats / Efeitos do contaminante alimentar semicarbazida na morfologia testicular de ratos Wistar jovens

O objectivo do presente trabalho foi avaliar os efeitos da semicarbazida na morfologia testicular de ratos Wistar jovens. Os animais foram tratados durante 30 dias com hidrocloreto de semicarbazida incorporado na dieta, nas concentrações de 0, 3 e 6g/kg. Os resultados obtidos revelaram uma diminuição estatisticamente significativa no diâmetro dos túbulos seminíferos, no diâmetro do lúmen dos túbulos seminíferos e na área ocupada pelo epitélio seminífero nos animais dos grupos experimentais em comparação com os animais do grupo controlo. Estes resultados evidenciam que a semicarbazida induz alterações importantes no desenvolvimento testicular e sugerem um estudo mais aprofundado sobre os mecanismos de acção, dos efeitos a longo prazo, da reversibilidade das lesões e nas capacidades reprodutivas. Estes aspectos são relevantes numa perspectiva de segurança alimentar, em particular para as crianças, as quais representam um grupo de maior exposição e susceptibilidade à semicarbazida.

Efeitos da semicarbazida no esqueleto de ratos Wistar em crescimento / Effects of semicarbazide on skeleton of growing Wistar rats

The effects of semicarbazide hydrochloride on skeletal tissues were evaluated using Wistar rats. In the animals submitted to the administration of semicarbazide, radiological examination showed bone and articular alterations with growth plates enlargement. Histological exams showed irregular patterns and proliferation of chondrocytes and excessive accumulation of extracellular matrix. Immunohistochemical exams showed PCNA positive reaction in pre- and hypertrofic chondrocytes. These results confirm that semicarbazide induces important changes in skeletal tissues and that has potential utility in experimental osteolathryrism.

Effect of dithiocarbamate thiram on Wistar rat growth plate and articular cartilage / Efeito do ditiocarbamato tirame sobre a placa de crescimento e cartilagem articular de ratos Wistar

Avaliou-se o efeito do tirame, ditiocarbamato largamente utilizado na agricultura como antifúngico e repelente de roedores, na ossificação endocondral de mamíferos, usando, como modelo, ratos Wistar. Não foram observadas lesões na cartilagem articular, nem nas placas de crescimento, o que pode ser atribuído à dose utilizada e à duração do ensaio. A diminuição da altura da placa de crescimento nos animais aos quais foi administrado o tirame parece traduzir o atraso verificado no crescimento em geral, e não um efeito específico na cartilagem, uma vez que as diferentes zonas da placa epifisária mantiveram as proporções dos animais do grupo-controle. Embora não tenham sido verificados, no presente trabalho, os efeitos registrados para outras espécies nos tecidos cartilaginosos, sugere-se a avaliação dos efeitos crónicos do tirame no crescimento e no desenvolvimento dos ossos longos em mamíferos.

Haematological and biochemical parameters in Churra-da-Terra-Quente ewes from the northeast of Portugal / Parâmetros hematológicos e bioquímicos de ovelhas da raça Churra da Terra Quente do nordeste de Portugal

Hematological and biochemical parameters, including plasma electrolytes and thyroid hormones, were determined in 73 clinically healthy Churra-da-Terra-Quente ewes, a typical breed from the northeast of Portugal. The hemogram values were: erythrocytes 9.8±1.5×10(12)/L; haemoglobin 118.1±19.1g/L; haematocrit 40.8±5.9 percent; leukocytes 5.7±1.8×10(9)/L; and platelets 544.3±177.2×10(9)/L. The thrombin time was 17.3±1.7 seconds. The values of biochemical parameters were: total protein 76.4±6.1g/L; glucose 2.87±0.60mmol/L; total cholesterol 1.65±0.33mmol/L; aspartate aminotransferase 155.9±49.2U/L; alanine aminotransferase 23.2±9.6U/L; γ-glutamyl transferase 48.0±18.7U/L; total alkaline phosphatase 121.6±76.1U/L; glutamate dehydrogenase 6.4±3.7U/L; urea 7.32±2.22mmol/L; creatinine 123.0±54.1μmol/L; total calcium 2.53±0.25mmol/L; phosphorus 2.10±0.46mmol/L; magnesium 1.01±0.09mmol/L; sodium 152.04±3.65mmol/L; potassium 4.7±0.4mmol/L; ionized calcium 1.32±0.07mmol/L; total thyroxine 111.75±42.29nmol/L; total triiodothyronine 1.01±0.28nmol/L; free T4 11.93±1.78pmol/L; free T3 4.22±1.33pmol/L; and thyroid-stimulating hormone 0.18±0.19μIU/mL. Although differences among the Churra-da-Terra-Quente breed and other breeds may occur, the hematological and biochemical parameters, plasma electrolytes, and thyroid hormones, for this indigenous breed, were generally situated within the reference intervals previously reported for sheep.

Os valores hematológicos e bioquímicos, incluindo os eletrólitos plasmáticos e os hormônios da tireoide, foram determinados em 73 ovelhas, clinicamente saudáveis, da raça Churra da Terra Quente, raça ovina característica do nordeste de Portugal. Os valores obtidos para o hemograma foram: eritrócitos 9,8±1,5×10(12) /L; hemoglobina 118,1±19,1g/L; hematócrito 40,8±5,9 por cento; leucócitos 5,7±1,8×10(9) /L e plaquetas 544,3±177,2×10(9)/L. O tempo de trombina foi de 17,3±1,7 segundos. Os valores dos parâmetros bioquímicos avaliados foram: proteínas totais 76,4±6,1g/L; glicose 2,87±0,60mmol/L; colesterol total 1,65±0,33mmol/L; aspartato amino transferase 155,9±49,2U/L; alanina amino transferase 23,2±9,6U/L; gama-glutamil transferase 48,0±18,7U/L; fosfatase alcalina total 121,6±76,1U/L; glutamato desidrogenase 6,4±3,7U/L; ureia 7,32±2,22mmol/L; creatinina 123,0±54,1μmol/L; cálcio total 2,53±0,25mmol/L; fósforo 2,10±0,46mmol/L e magnésio 1,01±0,09mmol/L; sódio 152,04±3,65mmol/L; potássio 4,7±0,4mmol/L e cálcio ionizado 1,32±0,07mmol/L; tiroxina total 111,75±42,29nmol/L; tri-iodotironina total 1,01±0,28nmol/L; T4 livre 11,93±1,78pmol/L; T3 livre 4,22±1,33pmol/L e hormônio estimulante da tireoide 0,18±0,19μIU/mL. Apesar de terem sido observadas algumas diferenças entre a raça Churra da Terra Quente e outras raças, os valores hematológicos e bioquímicos, eletrólitos plasmáticos e hormônios da tireóide, desta raça autóctone apresentam-se no geral situados dentro dos intervalos de referência publicados para a espécie ovina.

Expressão da caderina na discondroplasia tibial / Cadherin expression in the tibial dyschondroplasia

By immunohistochemistry the expression of a pan-cadherin antibody that recognizes a wide variety of cadherins in chondrocytes from normal and tibial dyschondroplasia (TD) growth plates was compared. Surprisingly, an upregulated expression that was not expected in TD lesion chondrocytes was observed. The reason for this apparent upregulation is not clear. The increased expression may simply be due to the particular phenotype of lesion chondrocytes, and cadherin may be involved in apoptosis of chondrocytes of TD lesion. Another possibility, is that a low level of calcium in the lesion may be responsible for the observed upregulation. The results of the present study suggest that the formation of the dyschondroplastic lesion is not merely due to the impaired terminal differentiation of lesion chondrocytes and that other mechanisms are probably involved in TD etiology. Further studies will be necessary to provide insight into the precise nature of the condition.

Assessment of markers of bone formation under controlled environmental factors and their correlation with serum minerals in adult sheep as a model for orthopaedic research.

Eighteen healthy skeletally mature (3 years old) ewes, with an average weight of 45 kg, of the Portuguese Churra da Terra Quente breed were used to evaluate the normal values of total and bone-specific isoform of alkaline phosphatase serum activities (ALP and BALP, respectively) and serum osteocalcin (OC) and their correlation with the serum minerals - calcium (Ca), phosphorus (P), magnesium (Mg) and ionized calcium (Ca(2+)). The sheep were maintained under controlled environmental conditions (constant diurnal photoperiod cycle and identical husbandry and feeding) for six weeks before the collection of the blood samples. The measurement of the total ALP and serum minerals was performed with automated biochemistry analysers using the BioMérieux kits, the serum electrolyte Ca(2+) Diametrics Medical, Inc specific cassettes and the BALP and OC METRATM kits from QUIDEL Corporation. The mean +/- standard deviation values obtained were: total ALP 90.17 +/- 85.72 U/L, BALP 15.0 +/- 5.44 U/L, ratio BALP/ total ALP 29.28 +/- 24.22, OC 13.02 +/- 1.87 ng/mL, Ca 2.57 +/- 0.37 mmol/L, P 2.13 +/- 0.42 mmol/L, Mg 1.04 +/- 0.13 mmol/L, Ca(2+) 1.29 +/- 0.04 mmol/L. Significant correlations were observed between the total ALP and Ca (r = 0.5939; P = 0.05) and OC and Ca (r = 0.5706; P = 0.05). Reference to the serum values of bone turnover parameters in sheep could be of great value in research and could provide complementary non-invasive information on the bone healing process, particularly with regard to obtaining an early prognosis of fracture healing.

Haematology, genotoxicity, enzymatic activity and histopathology as biomarkers of metal pollution in the shrew Crocidura russula.

Haematological (WBC, RBC, Hgb and Hct) and genotoxicity (MNT) parameters, hepatic enzymatic activities (GST, GPx and GR), and a histopathological evaluation of liver, kidneys and gonads were assessed as general biomarkers of metal pollution in the shrew Crocidura russula inhabiting a pyrite mining area. Specimens exposed to metals presented a few significant alterations when compared with reference animals: GST activity decreased; micronuclei increased; and evident liver alterations related to metal exposure were observed. On the basis of all the parameters studied, age was an important factor that partly explained the observed variation, whereas sex was the least important factor. Significant correlations were also found between heavy metal concentrations and biomarkers evaluated, demonstrating the great influence of these metals in the metabolic alterations. To the best of our knowledge, these data constitute the first measurements of a battery of biomarkers in shrews from a mine site and are among the few available for insectivorous mammals.

Evaluation of the antitumoral effect mediated by IL-12 and HSV-tk genes when delivered by a novel lipid-based system.

In the present work, we used a novel albumin-associated lipoplex formulation, containing the cationic lipid 1-palmitoyl-2-oleoyl-sn-glycero-3-ethylphosphocholine (EPOPC) and cholesterol (Chol), to evaluate the antitumoral efficacy of two gene therapy strategies: immuno-gene therapy, mediated by IL-12 gene expression, and "suicide" gene therapy, mediated by HSV-tk gene expression followed by ganciclovir (GCV) treatment. Our data show that, in an animal model bearing a subcutaneous TSA (mouse mammary adenocarcinoma) tumor, intratumoral administration of the albumin-associated complexes containing the plasmid encoding IL-12 results in a strong antitumoral effect, as demonstrated by the smaller tumor size, the higher T-lymphocyte tumor infiltration and the more extensive tumor necrotic and hemorrhagic areas, as compared to that observed in animals treated with control complexes. On the other hand, the application of the "suicide" gene therapy strategy results in a significant antitumoral activity, which is similar to that achieved with the immuno-gene therapy strategy, although involving different antineoplastic mechanisms. For the tested model, albumin-associated complexes were shown to efficiently mediate intratumoral delivery of therapeutic genes, thus leading to a significant antitumoral effect. This finding is particularly relevant since TSA tumors are characterized for being poorly immunogenic, aggressive and exhibiting high proliferation capacity.