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.     

Validation of the cumulative or replicate NAA method for the determination of trace elements in biological materials

Biological Trace Element Research - To make the best use of time and facilities, a neutron activation system, fully automatic, including spectrum and data processing, to be used with short-lived...     

Effect of Cerebellar Lesions on Monoamine Levels in Various Brain Areas of the Cat

Abstract: Modifications in the content of monoamines after different lesions of the cerebellar cortex were investigated in eight prosencephalic structures of cat's brain. Apart from other minor changes, lesions of the posterior vermis induced significant changes in the thalamus (decrease of DA and increase of 5-HT). Lesions of the cortex of a cerebellar hemisphere, on the other hand, produced an increase of 5-HT in the caudate nucleus and an increase of DA in the hippocampus in addition to a generalized increase of 5-HT in all the prosencephalic structures studied. These findings are discussed in relation to the anatomical connections of the lesioned areas and their expected role in the sleep-wakefulness cycle.     

Polymorphism in the promoter region of the mannose-binding lectin gene among human T-cell lymphotropic virus infected subjects

The present study investigated the frequency of the mutations at positions -550 and -221 of the mannose-binding lectin (MBL) gene in a sample of 75 human T-cell lymphotropic virus (HTLV) infected patients and 96 HTLV seronegative controls, in order to evaluate the occurrence of a possible association between the polymorphism and HTLV infection. A sequence specific primer-polymerase chain reaction was used for discrimination of the polymorphism. The analysis of allele frequencies at position -550 did not show any significant differences between HTLV infected group and controls, but there was a significant difference at position -221. The comparative analysis of haplotypes frequencies were not significant, but the genotype frequencies between the two groups, revealed a higher prevalence of genotype LYLX (25.3%), associated with medium and low MBL serum levels among HTLV infected subjects. The odds ratio estimation demonstrated that the presence of genotype LYLX was associated with an increased risk of HTLV infection (p = 0.0096; 1.38 < or = IC95% < or = 7.7605). There was no association between proviral load and the promoter polymorphism, but when promoter and exon 1 mutations were matched, it was possible to identify a significant higher proviral load among HTLV infected individuals carrying haplotypes correlated to low serum levels of MBL. The present study shows that the polymorphism in the promoter region of the MBL gene may be a genetic marker associated with HTLV infection, and emphasizes the need for further studies to determinate if the present polymorphism have any impact on diseases linked to HTLV infection.     

High evolutionary constraints limited adaptive responses to past climate changes in toad skulls

Interactions among traits that build a complex structure may be represented as genetic covariation and correlation. Genetic correlations may act as constraints, deflecting the evolutionary response from the direction of natural selection. We investigated the relative importance of drift, selection, and constraints in driving skull divergence in a group of related toad species. The distributional range of these species encompasses very distinct habitats with important climatic differences and the species are primarily distinguished by differences in their skulls. Some parts of the toad skull, such as the snout, may have functional relevance in reproductive ecology, detecting water cues. Thus, we hypothesized that the species skull divergence was driven by natural selection associated with climatic variation. However, given that all species present high correlations among skull traits, our second prediction was of high constraints deflecting the response to selection. We first extracted the main morphological direction that is expected to be subjected to selection by using within- and between-species covariance matrices. We then used evolutionary regressions to investigate whether divergence along this direction is explained by climatic variation between species. We also used quantitative genetics models to test for a role of random drift versus natural selection in skull divergence and to reconstruct selection gradients along species phylogeny. Climatic variables explained high proportions of between-species variation in the most selected axis. However, most evolutionary responses were not in the direction of selection, but aligned with the direction of allometric size, the dimension of highest phenotypic variance in the ancestral population. We conclude that toad species have responded to selection related to climate in their skulls, yet high evolutionary constraints dominated species divergence and may limit species responses to future climate change.     

Secretory structures at syconia and flowers of Ficus enormis (Moraceae): A specialization at ostiolar bracts and the first report of inflorescence colleters

The fig (Ficus L.) infructescence, called syconium, is a receptacle with an apical opening, the ostiole, closed by bracts. The ostiolar bracts produce an exudate, which is rather conspicuous in some species. It has not been histochemically analyzed yet, and the structures responsible for its production are still unknown. Some wild growing species of Ficus from Brazil produce high amounts of this ostiolar exudate. Ficus enormis (Mart. ex Miq.) Miq. grows as trees or shrubs in the Atlantic rainforest. Our goal was to identify the secretory structures present in the inflorescence and, to characterize histochemically the ostiolar tissues and exudates. Syconia samples of F. enormis were processed and stained according to the usual techniques in plant anatomy. The morphological analysis revealed different types of bracts, one type specialized in secretion, another showing transitional characteristics between secretory and non-secreting bracts, and a third one being non-secreting. They are designated as secretory ostiolar bracts, transitional bracts and wall bracts. The floral bracteoles, digital-shaped colleters present in the ostiole, at the syconium axis and at the flower receptacle, were also analyzed. All have similar structure, like finger-shaped secretory trichomes. The colleters present among ostiolar bracts may contribute to production and composition of the ostiole exudate.     

Phylogenetic analysis of the north‐east Atlantic and Mediterranean species of the genus Stenosoma (Isopoda,Valvifera, Idoteidae)

Xavier, R., Santos, A. M., Harris, D. J., Sezgin, M., Machado, M., Branco, M. (2012). Phylogenetic analysis of the north‐east Atlantic and Mediterranean species of the genus Stenosoma (Isopoda, Valvifera, Idoteidae). —Zoologica Scripta, 41, 386–399. The marine isopod genus Stenosoma is widespread in the northern hemisphere. However, 12 of its 14 known species are found within the Mediterranean basin and adjacent regions of the north‐east Atlantic and the Black Sea. Such a high level of diversity confined to a limited region of a much larger circumglobal distribution suggests that the Mediterranean region may have played a crucial role in the evolutionary history of this genus. In the present work, the phylogeny of the genus Stenosoma was investigated on the basis of DNA sequencing data from one nuclear (28SrRNA) and two mitochondrial (COI, ND4) gene fragments obtained for nine of 12 Atlantic–Mediterranean species. Divergence time estimates point to a Tethyan origin of Stenosoma and suggest that the speciation events from which stem most of the extant species took place well before the Messinian Salinity Crisis. Stenosoma spinosum and Stenosoma appendiculatum are the only exceptions, as they apparently arose within the Mediterranean during the Pleistocene. Phylogenetic reconstruction agrees with current taxonomic status of most species. However, Stenosoma capito clustered in two distinct and well‐supported clades, one composed of eastern Mediterranean and Black Sea specimens and the other by western Mediterranean and Atlantic ones. Such polyphyly suggests the existence of a previously unrecognized species, Stenosoma sp., which so far has been confounded with S. capito.     

Ligninolytic activity of tropical rainforest basidiomycetes

A total of 116 strains of Brazilian tropical rainforest basidiomycetes were evaluated in terms of their ability to oxidize the dye rhemazol brilliant blue R (RBBR) and guaiacol. Laccase and peroxidase activities were detected by the drop test using solutions of α-naphthol and pyrogallol, respectively. RBBR and guaiacol oxidation occurred in 96.6 and 87.1% of the strains tested, respectively. One hundred strains oxidized both substrates. In the drop test, most strains presented laccase (96.6%) and peroxidase (92.2%) activity. The quick screening method used here can be useful to identify ligninolytic fungal strains to be used in various biotechnological applications. This revised version was published online in November 2006 with corrections to the Cover Date.     

Thermal Stability and Activity Regain of Horseradish Peroxidase in Aqueous Mixtures of Imidazolium-Based Ionic Liquids

Thermal deactivation kinetics of horseradish peroxidase (HRP) were studied from 45 to 90 °C in phosphate buffer and 5–25% (v,w/v) 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF₄] and 1-butyl-3-methylimidazolium chloride [BMIM][Cl]. HRP activity at 25 °C was not affected by the presence of ionic liquids up to 20% (v,w/v). Increasing the ionic liquids concentration up to 25% (v,w/v) changed the biphasic character of deactivation kinetics to an apparent single first-order step. The presence of 5–10% (v/v) [BMIM][BF₄] significantly improved HRP thermal stability with lower activation energies for the deactivation second phase (83–87 kJ mol⁻¹). After deactivation, enhanced activity regain of the enzyme, up to 70–80% of the initial activity, was found in 25% (v/v) [BMIM][BF₄] and 10% (w/v) [BMIM][Cl] and correlated to prevalence of the deactivation first phase.