Histology and histopathology Vol.27, nº 6 (2012)

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    Molecular characterization of EGFR and EGFR-downstream pathways in triple negative breast carcinomas with basal like features
    (F. Hernandez y JuanF. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología., 2012) Martin, Vittoria; Botta, Francesca; Zanellato, Elena; Molinari, Francesca; Crippa, Stefano; Mazzucchelli, Luca; Frattini, Milo
    Aims: Triple negative breast cancer with basal like features (TN-BCBL) do not benefit from hormonal and anti-HER2 therapies. As a considerable fraction of TN-BCBLs shows EGFR deregulation, EGFR-targeted therapies have been proposed as an option. The characterization of EGFR and EGFR-downstream members may therefore provide important predictive information. Methods and results: Based on morphological and immunophenotypic features, we identified 38 TN-BCBLs that were subsequently investigated for alterations in EGFR signaling pathways. EGFR and PTEN protein levels were studied by immunohistochemistry, EGFR gene status by FISH, EGFR, H-Ras, K-Ras, N-Ras, BRAF and PIK3CA gene mutations by direct sequencing. EGFR overexpression and loss of PTEN expression characterized the majority of TN-BCBLs (76% and 74% of patients, respectively). EGFR gene copy number gain (FISH+) was identified in 51% of analyzable patients. PIK3CA gene mutations were detected in three cases (8%), whereas EGFR, H-Ras, K-Ras, N-Ras and BRAF genes showed no mutations. Overall, out of 17 patients classified as FISH+, 12 cases (70%) showed a concomitant alteration in PI3K/PTEN pathway. Conclusions: These results provide evidence that the efficacy of anti-EGFR drugs in TN-BCBL patients could be impaired by frequent alterations in the PI3K/PTEN axis, and suggest that TN-BCBLs could benefit from tailored treatments against this axis.
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    Histological study of the protective effect of melatonin on neural cells after neonatal hypoxia-ischemia
    (F. Hernandez y JuanF. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología., 2012) Alonso-Alconada, Daniel; Álvarez, Antonia; Lacalle, J.; Hilario, Enrique
    To minimize as much as possible the neurological consequences from hypoxic-ischemic (HI) brain injury, neuroprotective strategies are urgently required. In this sense, there is growing interest in the neuroprotective potential of melatonin after perinatal asphyxia, due to its high efficacy, low toxicity and ready cross through the blood-brain barrier. Twenty six Wistar rats at postnatal day 7 were randomly assigned to: two hypoxic-ischemic groups: pups with the left common carotid artery ligated and then submitted to hypoxia (HI group) and animals that received a dose of 15 mg/kg melatonin just after the hypoxic-ischemic event and repeated twice with an interval of 24 hours (HI+MEL group). Pups without ischemia or hypoxia were used as controls (Sham group). Seven days after surgery, brains were collected and coronal sections Nissl-stained, TUNEL-labeled, or MBP- and GFAP-immunolabeled prior to determining brain infarct area, quantify surviving neurons and evaluate oligodendroglial injury and reactive astrogliosis. The number of surviving neurons showing a well preserved architecture in HI+MEL group was similar to that observed in the Sham group. Moreover, TUNEL-positive cells only appeared in the HI group. The ratio of left-to-right hemispheric MBP immunostaining showed a significant decrease in the HI group in comparison with Sham pups, which was restored after melatonin administration. Melatonin also reduced reactive gliosis. Thus, our results suggest that treatment with melatonin after neonatal hypoxia-ischemia led to a neuroprotective effect reducing cell death, white matter demyelination and reactive astrogliosis.
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    Telocytes form networks in normal cardiac tissues
    (F. Hernandez y JuanF. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología., 2012) Rusu, Mugurel Constantin; Pop, F.; Hostiuc, S.; Curca, G.C.; Jianu, A.M.; Paduraru, D.
    Telocytes (TC) are a class of interstitial cells present in heart. Their characteristic feature is the presence of extremely long and thin prolongations (called telopodes). Therefore, we were interested to see whether or not TCs form networks in normal cardiac tissues, as previously suggested. Autopsy samples of cardiac tissues were obtained from 13 young human cadavers, without identifiable cardiac pathology and with a negative personal history of cardiovascular disease. Immunohistochemistry on formalin-fixed paraffin-embedded tissues was performed using monoclonal antibodies for CD117/c-kit. Additionally, ventricular samples from 5 Sprague-Dawley rats were ultrastructurally evaluated under transmission electron microscopy. We found c-kit positive cells with TC features in subepicardium, as well in subepicardial arteries and in subepicardial fat. TCs were also present in the subendocardium. Light and electron microscopy revealed the existence of intramyocardial networks built up by bipolar TCs. Larger c-kit positive multipolar TCs were found between cardiac muscle bundles. Our results support the existence of a cardiac network of telocytes.
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    Influence of a hypercholesterolemic diet on the collagen composition of the bladder wall extracellular matrix in rats
    (F. Hernandez y JuanF. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología., 2012) Nunes, R.L.V.; Bruschini, H.; Utsunomia, K.; Silveira, M.A.; Teodoro, W.R.; Leite, K.R.M.; Srougi, M.
    Purpose: To investigate the effects of hypercholesterolemic diet on the collagen composition of urinary bladder wall. Materials and methods: Forty-five female 4-week-old Wistar rats were divided into three groups: 1) control group fed a normal diet (ND); 2) model of bladder outlet obstruction (BOO) group fed a ND; and 3) group fed a HCD (1.25% cholesterol). Total serum cholesterol, LDL cholesterol and body weight were assessed at baseline. Four weeks later, group 2 underwent a surgical procedure resulting in a partial BOO, while groups 1 and 3 underwent a sham similar surgical procedure. Six weeks later, all animals had their bladders removed; serum cholesterol and LDL cholesterol levels and body weights were measured. Morphological and morphometric analysis was performed by Picrosirius staining and collagen types I and III were identified by immunofluorescence. Statistical analysis was completed and significance was considered when p<0.05. Results: Rats fed an HCD exhibited a significant increase in LDL cholesterol levels (p<0.001) and body weight (p=0.017), when compared to the groups fed a ND during the ten-week study period. Moreover, the HCD induced morphological alterations of the bladder wall collagen, regarding thin collagen fibers and the amounts of type III collagen when compared to the control group (p=0.002 and p=0.016, respectively), resembling the process promoted in the BOO model. Conclusions: A hyper-cholesterolemic diet in Wistar rats promoted morphological changes of the bladder types of collagen, as well as increases in body weight and LDL cholesterol.
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    High-intensity exercise training produces morphological and biochemical changes in adrenal gland of mice
    (F. Hernandez y JuanF. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología., 2012) Bartalucci, A.; Ferrucci, M.; Fulceri, F.; Lazzeri, G.; Lenzi, P.; Toti, L.; Serpiello, F.R.; La Torre, A.; Gesi, M.
    The effects of training are dependent on complex, adaptive changes which are induced by acute physical exercise at different levels. In particular, evidence shows that the hypothalamus-pituitary-adrenocortical axis, as well as the sympatho-adrenomedullary system, is mainly involved in mediating the physiological effects of physical exercise. The aim of the present study was to investigate, through a morphological and biochemical approach, the effects of training on the adrenal gland of mice, following two different protocols consisting of either low- or high-intensity training. Mice were run daily on a motorised treadmill for 8 weeks, at a velocity corresponding to 60% (low-intensity exercise) or 90% (high-intensity exercise) of the maximal running velocity previously determined by an incremental exercise test. We found that physical exercise produced an increase in the adrenal gland size compared with the control (sedentary) mice. The increase was 31.04% for mice that underwent high-intensity exercise and 10.08% for mice that underwent low intensity exercise, and this appeared to be the result of an increase in the area of both the adrenal cortex and adrenal medulla. Morphological analysis of the adrenal cortex showed that both types of exercise produced an increase in cytoplasmic vacuoles in steroidogenic cells, appearing more abundant after high-intensity exercise. No change was found in the reticulate zone. In the adrenal medulla, despite the absence of morphological changes, immunohistochemistry for tyrosine hydroxylase, dopamine ß-hydroxylase and phenyl-ethanolamine-N-methyltransferase demonstrated an increased immunopositivity for these cathecolamine-synthesizing enzymes after intense exercise. These results were confirmed by immunoblot accompanied by densitometric analysis.