Familial breast/ovarian cancer and BRCA1/2 genetic screening: the role of immunohistochemistry as an additional method in the selection of patients.

Only 20-25% of families screened for BRCA1/2 mutations are found positive. Because only a positive result is informative, we studied the role of BRCA1/2 immunohistochemistry as an additional method for patient selection. From 53 high-risk-affected probands, 18 (34%) had available paraffin blocks of their tumors and were selected for this study. Mutation screening was done by conformation-sensitive gel electrophoresis and multiplex ligation-dependent probe amplification. For immunohistochemistry, 21 neoplastic specimens (15 breast carcinomas, 5 ovary neoplasms, and 1 rectal adenocarcinoma) were analyzed with BRCA1 (monoclonal antibody, Ab-1, oncogene) and BRCA2 (polyclonal antibody, Ab-2, oncogene) antibodies. Absence of the BRCA1 protein was confirmed in negative tumors by Western blotting. Seven patients were positive for BRCA1/2 mutations: 5 for BRCA1 and 2 for BRCA2. Four out of five positive patients had tumors negative for BRCA1 immunostaining, and the remaining 13 BRCA1-negative patients had positive BRCA1 immunostaining in all tumor samples. Sensitivity to predict for BRCA1 mutation carriers was 80%, and specificity was 100%, with a positive predictive value of 100% and a negative predictive value of 93%. This correlation was statistically significant (p=0.001). No correlation was observed for BRCA2. If larger studies confirm these results, high-risk patients with BRCA1-negative tumors should be screened first for this gene.     

Multilocus and morphological analysis of south-eastern Iberian Wall lizards (Squamata,Podarcis)

The phylogenetic relationships among the wall lizards of the Podarcis hispanicus complex that inhabit the south-east (SE) of the Iberian Peninsula and other lineages of the complex remain unclear. In this study, four mitochondrial and two nuclear markers were used to study genetic relationships within this complex. The phylogenetic analyses based on mtDNA gene trees constructed with ML and BI, and a species tree using *BEAST support three divergent clades in this region: the Valencia, Galera and Albacete/Murcia lineages. These three lineages were also corroborated in species delimitation analyses based on mtDNA using bPTP, mPTP, GMYC, ABGD and BAPS. Bayesian inference species delimitation method (BPP) based on both nuclear data and a combined data set (mtDNA + nuclear) showed high posterior probabilities for these three SE lineages (≥0.94) and another Bayesian analysis (STACEY) based on combined data set recovered the same three groups in this region. Divergence time dating of the species tree provided an estimated divergence of the Galera lineage from the other SE group (Podarcis vaucheri, (Albacete/Murcia, Valencia)) at 12.48 Ma. During this period, the Betic–Rifian arc was isolated, which could have caused the isolation of the Galera form distributed to the south of the Betic Corridor. Although lizards from the Albacete/Murcia and Galera lineage are morphologically similar, they clearly represent distinct genetic lineages. The noteworthy separation of the Galera lineage enables us to conclude that this lineage must be considered as a new full species.     

Flooded native pastures of the northern region of the Pantanal of Mato Grosso: biomass and primary productivity variations.

The Pantanal comprises a number of landscape units, submitted to a flood pulse with variable intensity or regularity. One of these units, the flooded plains, is important in cattle raising. This study was carried out in the northern portion of the Pantanal and presents data related to the productive dynamics of the flooded native pastures both protected from and exposed to cattle. The greatest total biomass values were for the protected pasture due to accumulated dead biomass. Net primary production presented smaller values at the flood-season start and increasing gradually beginning in the subsequent rainy season. However, consumption by cattle was also more intense during the months of greater precipitation. The effect of cattle in pastures is of fundamental importance to management since it prevents the dead biomass excess that increases fire risks.     

Renal oncocytoma: origin from the collecting duct

The histo- and cytogenesis of two cases of renal oncocytoma have been studied by cytomorphological and cytochemical methods. Transitions from collecting ducts into oncocytic tubules were observed at the light and electron microscopic levels. The fine structure of the oncocytes in tubules and tumors is described in detail. Cytochemically, the oncocytic tubules and oncocytomas share many characteristics with the distal nephron, especially the collecting ducts. A striking difference is the enhanced activity of succinic dehydrogenase which corresponds to the increase in the number of mitochondria in oncocytes. All the results suggest that renal oncocytoma originates from the collecting duct.     

The cytotaxonomy ofEmilia spp. (Asteraceae: Senecioneae) occurring in Brazil

Analysis of several populations in a large part of the distribution area of the genusEmilia in Brazil has revealed only two species: the diploidE. sonchifolia and the tetraploidE. fosbergii. The more widely reportedE. coccinea was not found. They show a karyotype constancy in morphology and chromosome number (2n = 10 and 2n = 20, respectively), C-banding pattern and number of secondary constrictions. Some indications were found thatE. fosbergii may be an allopolyploid and that its ancestors had different genome sizes.     

Histopathology of experimental Aspergillus fumigatus keratitis

Histopathological studies in rabbit's eyes, 7 and 14 days after intracorneal inoculation with 1×10⁵ Aspergillus fumigatus conidia have been performed.Similar lesions were found in both periods with fungal hyphae in the anterior third of corneal stroma, round cell infiltration from the sclero-corneal edge and in the anterior chamber and, neovascularization.No lesions were found in the Descemet's membrane.Gomori silver-methenamine stain with hematoxiline-eosine counter-stain was found to be the most reliable stain to detect fungal presence in corneal stroma, and Masson's trichromic stain in the study of pathological changes in ocular elements.     

Gating properties of channels formed by colicin Ia in planar lipid bilayer membranes

Summary Colicin Ia forms voltage-dependent channels when incorporated into planar lipid bilayers. A membrane containing many Colicin Ia channels shows a conductance which is turned on when high positive voltages (>+10 mV) are applied to thecis side (side to which the protein is added). The ionic current flowing through the membrane in response to a voltage step shows at first an exponential and then a linear rise with time. The relationship between the steady-state conductance, achieved immediately after the exponential portion, and voltage is S-shaped and is adequately fit by a Boltzmann distribution. The time constant () of the exponential is also dependent on voltage, and the relation between these two parameters is asymmetric aroundV _o (voltage at which half of the channels are open). In both cases the steepness of the voltage dependence, a consequence of the number of effective gating particles (n) present in the channel, is greatly influenced by the pH of the bathing solutions. Thus, increasing the pH leads to a reduction inn, while acidic pH's have the opposite effects. This result is obtained either by changing the pH on both sides of the membrane or on only one side, be itcis orrans. On the other hand, changing pH on only one side by addition of an impermeant buffer fails to induce any change inn. At the single-channel level, pH had an effect both on the unitary conductance, doubling it in going from pH 4.5 to 8.2, as well as on the fraction of time the channels stay open,F _(v). For a given voltage,F _(v) is clearly diminished by increasing the pH. This titration of the voltage sensitivity leads to the conclusion that gating in the Colicin Ia molecule is accomplished by charged amino-acid residues present in the protein molecule. Our results also support the notion that these charged groups are inside the aqueous portion of the channel.     

Chemotherapy of Aspergillus fumigatus keratitis: An experimental study

An experimental Keratitis study of Aspergillus fumigatus was performed in 130 rabbits divided into 12 groups of ten animals each. Three antifungal drugs (myconazole, amphotericin B and pimaricin) were tested using two procedures (topical drops and subconjunctival injections) and two different concentrations (500 and 10 000 times the MIC). In each case, the drugs were applied every 3 h starting 14 h after inoculation. Miconazole was useful at 10 mg/ ml concentration by topical drops and subconjunctival injections, but was less useful at 5 mg/ ml. Amphotericin B was useful at 5 mg/ ml concentration by topical drops and less useful at 2 mg/ ml.No differences were found between the two concentrations by subconjunctival administration. Pimaricin was useful by topical drops at 50 mg/ ml concentration and less useful at 10 mg/ ml as well as by subconjunctival injections.