Clinical Tooth Color Matching: In Vivo Comparisons of Digital Photocolorimetric and Spectrophotometric Analyses.

OBJECTIVE: This study aimed to compare the tooth color matching of two dental colorimetric methods: the spectrophotometric analysis (SPM) and the standardized digital photocolorimetric analysis (DPC). METHODS: The color of 60 maxillary central incisors of 30 volunteers (22.5 ± 7.6 years) was analyzed. In the DPC method, tooth photographs were standardized with the eLABor_aid protocol, processed with Adobe Photoshop Lightroom software, and the values of L*, a*, and b* were obtained with a Digital Color Meter software. For the SPM, L*, a*, and b* were measured directly with a handheld spectrophotometer. Data were submitted to paired t-test and Pearson correlation test (α=0.05). Mean color difference between the two methods was calculated with CIELAB formula. RESULTS: All color coordinates revealed different values when comparing DPC to SPM in the same tooth (p<0.0001). Mean color difference (ΔEab) between SPM and DPC was 11.5 ±3.1. A positive correlation was observed for L* (R2=0.73,p<0.0001), a* (R2=0.31, p=0.017), and b* (R2=0.83, p<0.0001). CONCLUSIONS: Even though the color coordinate values were different in both methods, they were correlated, revealing that the DPC is a viable alternative to determine the tooth color matching.

Hemicelluloses and associated compounds determine gall functional traits.

The intriguing questions concerning gall development refer to the processes of the remodelling of the host plant organ. Such processes involve the restructuring of cell walls and can be influenced by phenolics, indole-3-acetic acid (IAA) and reactive oxygen species (ROS). Alterations in cell walls demand the interference in the coupling of cellulose fibrils and hemicelluloses (xyloglucans) at specific stages of gall development. In addition to cell wall remodelling, hemicelluloses, such as the, xyloglucans and heteromannans can act as reserve carbohydrates, while xylans provide rigidity to the secondary cell walls. Developmental traits of the lenticular, fusiform and globoid galls on Inga ingoides (Fabaceae) were analysed using anatomical, cytometric, histochemical and immunocytochemical tools. Phenolics, IAA and ROS accumulated in similar gall tissue compartments, and may have influenced the restructuring of hemicelluloses and pectins. Contrary to expectations, cell wall flexibility regarding the dynamics of xyloglucans and cellulose fibrils does not relate to a temporal scale. The detection of xyloglucans in nutritive cell walls relate to carbohydrate nutritional resources to the galling insect, while xylans were associated to the lignified cell walls. Heteromanans were not detected, either in non-galled or galled tissues. The patterns of cell expansion during gall development relied on the relationship among phenolics, ROS and IAA with the hemicelluloses (xyloglucans and xylans) and cellulose fibrils. Although cell wall dynamics is specific to each gall morphotype in I. ingoides, the xyloglucans function as carbohydrate reserve to the gall inducers, which constitutes a functional trait common to the three morphotypes.

Enzyme-mediated metabolism in nutritive tissues of galls induced by Ditylenchus gallaeformans (Nematoda: Anguinidae).

The galls induced by Ditylenchus gallaeformans (Nematoda) on leaves of Miconia albicans have unique features when compared to other galls. The nematode colonies are surrounded by nutritive tissues with promeristematic cells, capable of originating new emergences facing the larval chamber, and providing indeterminate growth to these galls. Considering enzyme activity as essential for the translocation of energetic molecules from the common storage tissue (CST) to the typical nutritive tissue (TNT), and the major occurrence of carbohydrates in nematode galls, it was expected that hormones would mediate sink strength relationships by activating enzymes in indeterminate growth regions of the galls. Histochemical, immunocytochemical and quantitative analyses were made in order to demonstrate sites of enzyme activity and hormones, and comparative levels of total soluble sugars, water soluble polysaccharides and starch. The source-sink status, via carbohydrate metabolism, is controlled by the major accumulation of cytokinins in totipotent nutritive cells and new emergences. Thus, reducing sugars, such as glucose and fructose, accumulate in the TNT, where they supply the energy for successive cycles of cell division and for nematode feeding. The histochemical detection of phosphorylase and invertase activities indicates the occurrence of starch catabolism and sucrose transformation into reducing sugars, respectively, in the establishment of a gradient from the CST towards the TNT. Reducing sugars in the TNT are important for the production of new cell walls during the indeterminate growth of the galls, which have increased levels of water-soluble polysaccharides that corroborate such a hypothesis. Functional relationship between plant hormone accumulation, carbohydrate metabolism and cell differentiation in D. gallaeformans-induced galls is attested, providing new insights on cell development and plant metabolism.

Comparison of iterated single-step and Bayesian regressions on genomic evaluations for age at 100 kg in swine.

The effects of modified single-step genomic best linear unbiased prediction (ssGBLUP) iterations on GEBV and SNP were investigated using 85,388 age at 100 kg phenotypes from the BRF SA breeding program Landrace pure line animals, off-tested between 2002 and 2013. Pedigree data comprised animals born between 1999 and 2013. A total of 1,068 animals were assigned to the training population, in which all of them had genotypes, original and corrected age at 100 kg phenotypes, and weighted deregressed proof records. A total of 100 genotyped animals, with high accuracy age at 100 kg estimated breeding values, were assigned to the validation population. After applying the quality control workflow, a set of 41,042 SNP was used for the analysis. Standard and modified ssGBLUP, BayesCπ, and Bayesian Lasso were compared, and their predictive abilities were accessed by approximate true and GEBV correlations. Modified ssGBLUP iteration effects on SNP estimates and GEBV were relevant, in which assigned differential weights and shrinkage caused important losses on ssGBLUP predictive ability for age at 100 kg GEBV. Even though ssGBLUP accuracy can be equal or better than the compared Bayesian methods, additional gains can be obtained by correctly identifying the number of iterations required for best ssGBLUP performance.

Efeito de fungos micorrízicos arbusculares na bioprodução de fenóis totais e no crescimento de Passiflora alata Curtis / Total phenols in Passiflora alata Curtis inoculated with mycorrhizal fungi

Os compostos fenólicos encontrados no extrato das folhas de maracujazeiro doce (Passiflora alata Curtis) são os principais responsáveis pelos efeitos terapêuticos, incluindo a atividade ansiolítica. O presente trabalho avaliou o efeito de diferentes espécies de fungo micorrízicos arbusculares (FMAs) e doses de fósforo sobre a bioprodução de fenóis totais, bem como, o crescimento vegetal e os conteúdos de nitrogênio, fósforo e potássio na massa da matéria seca da parte aérea do maracujazeiro doce. O experimento, fatorial 4x2, foi conduzido em um telado com quatro tratamentos microbiológicos: Glomus etunicatum, Glomus intraradices, inóculo misto (Glomus clarum e Gigaspora margarita) e o controle sem fungo, e duas doses de fósforo: 0 e 50 mg kg-1 de solo. O delineamento experimental foi de blocos casualizados com quatro repetições. As plantas foram colhidas 90 dias após a semeadura. Na ausência da adubação fosfatada, o conteúdo de fenóis totais, a massa da matéria seca da parte aérea e o número de folhas foram maiores nos tratamentos inoculados com FMAs, quando comparados ao tratamento sem fungo. Plantas com inóculo misto apresentaram maior altura com ou sem adubação fosfatada. Os tratamentos inoculados com FMAs, tanto na dose 0 quanto na dose 50 mg kg-1 de P incrementaram os conteúdos de N, P e K na parte aérea do maracujazeiro doce, evidenciando a capacidade dos FMAs em promover o melhor estado nutricional das plantas.

The phenolic compounds found in extracts from leaves of sweet passion fruit (Passiflora alata) are mainly responsible for its therapeutic effects, such as the anxiolytic activity. This study evaluated the effects of different species of mycorrhizal fungi (AMF) and phosphorus levels on the bioproduction of total phenols, as well as plant growth and the contents of nitrogen, phosphorus and potassium in the dry mass of shoots of sweet passion fruit. The experiment was conducted in a greenhouse. The factors were arranged in a :[(microbiological treatments: Glomus etunicatum, Glomus intraradices, mixed inoculum (Glomus clarum and Gigaspora margarita) and without fungus] x 2 (doses of phosphorus: 0 and 50 mg kg-1 soil) factorial arrangement, in a randomized block experimental design with four replications. The plants were harvested 90 days after seeding. In the absence of phosphate fertilization, the total phenol content, dry mass of shoot and leaf number were greater in treatments inoculated with AMF compared to the treatments without fungus. Mixed inoculum plants had higher plant height with or without phosphate fertilization. Treatments inoculated with AMF in both the 0 and 50 mg kg-1 doses of P increased the content of N, P and K in the shoots of sweet passion fruit, demonstrating the ability of AMF to promote better nutritional statusfin plants.

Effect of tooth bleaching on bond strength of enamel-dentin cavities restored with silorane- and dimethacrylate-based materials.

The aim of this study was to evaluate the influence of tooth bleaching on the push-out bond strength of a composite resin based on dimethacrylates and silorane to cavities that involve both enamel and dentin. A total of 80 bovine incisors were sectioned on the buccal surface to obtain specimens (10 × 10 mm) presenting enamel and dentin (1-mm thick each substrate). The specimens were randomly distributed into eight groups (n=10), according to the bleaching protocol (1--none; 2--10% carbamide peroxide [CP] for 21 days, six hours each day; 3--three applications of 35% hydrogen peroxide [HP] in 15-minute sessions, one session every seven days for three weeks; 4--10% CP for 18 days, six hours each day + three applications of 35% HP in 15-minute sessions, one session every seven days for three weeks) and the restorative system applied (Adper Single Bond 2 + Filtek Supreme; Filtek Silorane adhesive and composite resin). After treatment, cavities were made (1.2-mm diameter on dentin; 1.5-mm diameter on enamel) with a diamond bur. At 24 hours after restoration, a push-out bond strength test was performed at a crosshead speed of 0.5 mm/min. The bleaching treatments did not significantly affect the bond strengths of either restorative system to enamel-dentin. Regardless of the bleaching treatment, the dimethacrylate-based resin system exhibited significantly higher bond strengths to enamel-dentin than did the silorane-based system.

Positive response to imatinib mesylate therapy for childhood chronic myeloid leukemia

Chronic myeloid leukemia (CML) is rare in the pediatric population, accounting for 2-3 percent of childhood leukemia cases, with an annual incidence of one case per million children. The low toxicity profile of imatinib mesylate has led to its approval as a front-line therapy in children for whom interferon treatment has failed or who have relapsed after allogeneic transplantation. We describe the positive responses of 2 children (case 1 - from a 7-year-old male since May 2005; case 2 - from a 5-year-old female since June 2006) with Philadelphia-positive chromosome CML treated with imatinib (300 mg/day, orally) for up to 28 months, as evaluated by morphological, cytogenetic, and molecular approaches. Our patients are alive, are in the chronic phase, and are in continuous morphological complete remission.

Positive response to imatinib mesylate therapy for childhood chronic myeloid leukemia.

Chronic myeloid leukemia (CML) is rare in the pediatric population, accounting for 2-3% of childhood leukemia cases, with an annual incidence of one case per million children. The low toxicity profile of imatinib mesylate has led to its approval as a front-line therapy in children for whom interferon treatment has failed or who have relapsed after allogeneic transplantation. We describe the positive responses of 2 children (case 1 - from a 7-year-old male since May 2005; case 2 - from a 5-year-old female since June 2006) with Philadelphia-positive chromosome CML treated with imatinib (300 mg/day, orally) for up to 28 months, as evaluated by morphological, cytogenetic, and molecular approaches. Our patients are alive, are in the chronic phase, and are in continuous morphological complete remission.

Alternagin-C, a disintegrin-like protein from the venom of Bothrops alternatus, modulates alpha2ß1 integrin-mediated cell adhesion, migration and proliferation

The alpha2ß1 integrin is a major collagen receptor that plays an essential role in the adhesion of normal and tumor cells to the extracellular matrix. Alternagin-C (ALT-C), a disintegrin-like protein purified from the venom of the Brazilian snake Bothrops alternatus, competitively interacts with the alpha2ß1 integrin, thereby inhibiting collagen binding. When immobilized in plate wells, ALT-C supports the adhesion of fibroblasts as well as of human vein endothelial cells (HUVEC) and does not detach cells previously bound to collagen I. ALT-C is a strong inducer of HUVEC proliferation in vitro. Gene expression analysis was done using an Affimetrix HU-95A probe array with probe sets of 10,000 human genes. In human fibroblasts growing on collagen-coated plates, ALT-C up-regulates the expression of several growth factors including vascular endothelial growth factor, as well as some cell cycle control genes. Up-regulation of the vascular endothelial growth factor gene and other growth factors could explain the positive effect on HUVEC proliferation. ALT-C also strongly activates protein kinase B phosphorylation, a signaling event involved in endothelial cell survival and angiogenesis. In human neutrophils, ALT-C has a potent chemotactic effect modulated by the intracellular signaling cascade characteristic of integrin-activated pathways. Thus, ALT-C acts as a survival factor, promoting adhesion, migration and endothelial cell proliferation after binding to alpha2ß1 integrin on the cell surface. The biological activities of ALT-C may be helpful as a therapeutic strategy in tissue regeneration as well as in the design of new therapeutic agents targeting alpha2ß1 integrin.

Disintegrins: integrin selective ligands which activate integrin-coupled signaling and modulate leukocyte functions

Extracellular matrix proteins and cell adhesion receptors (integrins) play essential roles in the regulation of cell adhesion and migration. Interactions of integrins with the extracellular matrix proteins lead to phosphorylation of several intracellular proteins such as focal adhesion kinase, activating different signaling pathways responsible for the regulation of a variety of cell functions, including cytoskeleton mobilization. Once leukocytes are guided to sites of infection, inflammation, or antigen presentation, integrins can participate in the initiation, maintenance, or termination of the immune and inflammatory responses. The modulation of neutrophil activation through integrin-mediated pathways is important in the homeostatic control of the resolution of inflammatory states. In addition, during recirculation, T lymphocyte movement through distinct microenvironments is mediated by integrins, which are critical for cell cycle, differentiation and gene expression. Disintegrins are a family of low-molecular weight, cysteine-rich peptides first identified in snake venom, usually containing an RGD (Arg-Gly-Asp) motif, which confers the ability to selectively bind to integrins, inhibiting integrin-related functions in different cell systems. In this review we show that, depending on the cell type and the microenvironment, disintegrins are able to antagonize the effects of integrins or to act agonistically by activating integrin-mediated signaling. Disintegrins have proven useful as tools to improve the understanding of the molecular events regulated by integrin signaling in leukocytes and prototypes in order to design therapies able to interfere with integrin-mediated effects.

Disintegrins: integrin selective ligands which activate integrin-coupled signaling and modulate leukocyte functions.

Extracellular matrix proteins and cell adhesion receptors (integrins) play essential roles in the regulation of cell adhesion and migration. Interactions of integrins with the extracellular matrix proteins lead to phosphorylation of several intracellular proteins such as focal adhesion kinase, activating different signaling pathways responsible for the regulation of a variety of cell functions, including cytoskeleton mobilization. Once leukocytes are guided to sites of infection, inflammation, or antigen presentation, integrins can participate in the initiation, maintenance, or termination of the immune and inflammatory responses. The modulation of neutrophil activation through integrin-mediated pathways is important in the homeostatic control of the resolution of inflammatory states. In addition, during recirculation, T lymphocyte movement through distinct microenvironments is mediated by integrins, which are critical for cell cycle, differentiation and gene expression. Disintegrins are a family of low-molecular weight, cysteine-rich peptides first identified in snake venom, usually containing an RGD (Arg-Gly-Asp) motif, which confers the ability to selectively bind to integrins, inhibiting integrin-related functions in different cell systems. In this review we show that, depending on the cell type and the microenvironment, disintegrins are able to antagonize the effects of integrins or to act agonistically by activating integrin-mediated signaling. Disintegrins have proven useful as tools to improve the understanding of the molecular events regulated by integrin signaling in leukocytes and prototypes in order to design therapies able to interfere with integrin-mediated effects.

Alternagin-C, a disintegrin-like protein from the venom of Bothrops alternatus, modulates alpha2beta1 integrin-mediated cell adhesion, migration and proliferation.

The alpha2beta1 integrin is a major collagen receptor that plays an essential role in the adhesion of normal and tumor cells to the extracellular matrix. Alternagin-C (ALT-C), a disintegrin-like protein purified from the venom of the Brazilian snake Bothrops alternatus, competitively interacts with the alpha2beta1 integrin, thereby inhibiting collagen binding. When immobilized in plate wells, ALT-C supports the adhesion of fibroblasts as well as of human vein endothelial cells (HUVEC) and does not detach cells previously bound to collagen I. ALT-C is a strong inducer of HUVEC proliferation in vitro. Gene expression analysis was done using an Affimetrix HU-95A probe array with probe sets of approximately 10,000 human genes. In human fibroblasts growing on collagen-coated plates, ALT-C up-regulates the expression of several growth factors including vascular endothelial growth factor, as well as some cell cycle control genes. Up-regulation of the vascular endothelial growth factor gene and other growth factors could explain the positive effect on HUVEC proliferation. ALT-C also strongly activates protein kinase B phosphorylation, a signaling event involved in endothelial cell survival and angiogenesis. In human neutrophils, ALT-C has a potent chemotactic effect modulated by the intracellular signaling cascade characteristic of integrin-activated pathways. Thus, ALT-C acts as a survival factor, promoting adhesion, migration and endothelial cell proliferation after binding to alpha2beta1 integrin on the cell surface. The biological activities of ALT-C may be helpful as a therapeutic strategy in tissue regeneration as well as in the design of new therapeutic agents targeting alpha2beta1 integrin.

Jararhagin, a snake venom metalloproteinase, induces a specialized form of apoptosis (anoikis) selective to endothelial cells.

Jararhagin is a snake venom metalloproteinase (SVMP) from Bothrops jararaca involved in several hemostatic and inflammatory disorders that occur in human envenomings. In this study, we evaluated the effect of jararhagin on endothelial cells (tEnd). The exposure of tEnd to jararhagin (20 and 40microg/ml) resulted in apoptosis with activation of pro-caspase-3 and alterations in the ratio between Bax/Bcl-xL. We observed that apoptosis was followed by decrease of cell viability and the loss of cell adhesion. Jararhagin induced changes in cell shape with a decrease in cell spreading, rounding up and detachment. This was accompanied by a rearrangement of actin network and a decrease in FAK association to actin and in tyrosine phosphorylated proteins. Morphological alterations and apoptosis were abolished when jararhagin catalytic activity was inhibited, indicating the importance of catalysis. Treatment of murine peritoneal adherent cells or fibroblasts with jararhagin did not result in apoptosis. The data indicate that the pro-apoptotic effect of jararhagin is selective to endothelial cells, interfering with the adhesion mechanisms and inducing anoikis. The present model might be useful for the study of the relationships between the architectural changes in the cytoskeleton and the complex phenomenon named anoikis.

Parâmetros genéticos para características lineares de úbere, escore final de tipo, produçäo de leite e produçäo de gordura na raça Holandesa / Genetic parameters for linear udder traits, final score and milk and fat yields in Holstein

Utilizaram-se 3.063 registros de classificaçäo linear de 2.593 vacas, obtidos entre 1997 e 1999, para estudar características de úbere, escore final de tipo e produçöes de leite e gordura por meio de modelo animal de repetibilidade para características múltiplas tomadas três a três. As médias das características de úbere variaram de 3,79 para colocaçäo das tetas anteriores a 5,81 para altura do úbere posterior. A média do escore final para tipo foi 80 e para produçöes de leite e gordura foram, respectivamente, 7.019±1.817kg e 236±60kg. As repetibilidades variaram de 0,46 para profundidade do úbere a 0,76 para escore final de tipo, e as herdabilidades de 0,11 para ligamento suspensório mediano a 0,40 para escore final. Em geral, as correlaçöes genéticas entre as características lineares de úbere foram altas e positivas. O maior valor foi entre altura e profundidade do úbere (0,71), seguida da correlaçäo entre inserçäo anterior e profundidade do úbere (0,69). Ao envolver características produtivas e de úbere, o maior valor foi 0,46, obtido entre produçäo de leite e largura do úbere posterior. A correlaçäo entre produçäo de gordura e largura do úbere foi moderada (0,23). Algumas correlaçöes foram negativas e em geral as fenotípicas foram, em valores absolutos, inferiores às genéticas

Comparaçäo da produçäo de leite e de gordura e da duraçäo da lactaçäo entre cinco "graus de sangue" originados de cruzamentos entre Holandês e Gir em Minas Gerais / Effect of breed group on milk and fat milk yield and on lactation lenght of Brazilian crossbred dairy cows

Para comparar as produçöes de leite e gordura e a duraçäo da lactaçäo de animais de cinco "graus de sangue" (1/2, 3/4, 7/8, 15/16 e 31/32) originados de cruzamentos entre Holandês e Gir foram formados três conjuntos de dados. O conjunto 1 foi constituído de 9.817 lactaçöes, 3.012 registros de primeira lactaçäo e 122 rebanhos; o conjunto 2, de 7.839 lactaçöes, 2.334 registros de primeira lactaçäo e 75 rebanhos; e o conjunto 3, de 5.236 lactaçöes, 1.468 registros de primeira lactaçäo e 38 rebanhos. As médias da produçäo de leite, de gordura e da duraçäo da lactaçäo de todas as lactaçöes nos conjuntos 1, 2 e 3 foram, respectivamente: 4.532+/-17Kg, 157+/-1Kg e 290+/-1 dias; 4.514+/-18kg, 157+/-kg e 292+/- 1 dias; e 4.495+/-22Kg, 156+/-1Kg e 293+/-1 dias. Os animais de "grau de sangue" 31/32 foram superiores aos demais quanto à produçäo de leite, à de gordura e à duraçäo da lactaçäo. Os animais 7/8 e 15/16 tiveram desempenho semelhante e os 1/2 apresentaram pior desempenho

Selective effect of hypothyroidism on expression of myelin markers during development.

Thyroid hormones are critical for maturation of the central nervous system. In a previous study, we showed a change in the pattern of mature myelinated nerve fibers by 2'3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) in developing hypothyroid animals, which suggests a possible role for thyroid hormones in myelin compaction. The classical myelin markers myelin basic protein (MBP) and proteolipidic protein (PLP) are expressed later in oligodendroglial development, when myelin sheath formation is in progress. A myelin constituent designated myelin-associated/oligodendrocytic basic protein (MOBP) has been identified and related to myelin compaction. We assessed the developmental sequence of appearance of CNPase, MBP, MOPB, and PLP proteins in cerebellum (Cb) and corpus callosum (cc) in an experimental hypothyroidism model. The appearance of both MOBP isoforms occurred at postnatal day (P)25 and P30 in cc and Cb, respectively, followed by an increase with age in the control group. However, all the MOBP isoforms were weakly detectable in both regions at P30 from the hypothyroid (H) group, and the higher molecular weight isoform remains decreased in cc, even at P90. The developmental pattern of expression of CNPase, MBP, and PLP proteins was also delayed in the H group. CNPase and MBP expression was recovered in cc and Cb, whereas PLP remained below control levels at P90 in cc. Our data show that the experimental hypothyroidism affects the developmental pattern of the oligodendrocytic/myelin markers. Furthermore, thyroid hormone may modulate specific genes, as demonstrated by permanent down-regulation of MOBP and PLP expression in adulthood.

Contribution of heparan sulfate to the non-permissive role of the midline glia to the growth of midbrain neurites.

Radial glial cells and astrocytes are heterogeneous with respect to morphology, cytoskeletal- and membrane-associated molecules and intercellular interactions. Astrocytes derived from lateral (L) and medial (M) midbrain sectors differ in their abilities to support neuritic growth of midbrain neurons in coculture (Garcia-Abreu et al. J Neurosci Res 40:471, 1995). There is a correlation between these abilities and the differential patterns of laminin (LN) organization that is fibrillar in growth-permissive L astrocytes and punctate in the non-permissive M astroglia (Garcia-Abreu et al. NeuroReport 6:761, 1995). There are also differences in the production of glycosaminoglycans (GAGs) by L and M midbrain astrocytes (Garcia-Abreu et al. Glia 17:339, 1996). We show that the relative amounts of the glycoproteins laminin LN, fibronectin (FN) and tenascin (TN) are virtually identical in L and M glia, thus, confirming that an abundant content of LN is not sufficient to promote neurite growth. To further analyze the role of GAGs in the properties of M and L glia, we employed enzymatic degradation of the GAGs chondroitin sulfate (CS) and heparan sulfate (HS). Treatment with chondroitinase has little effect on the non-permissive properties of M glia but reduces the growth-supporting ability of L glia. By contrast, heparitinase I produces no significant changes on L glia but leads to neurite growth promotion by M glia. Taken together, these results suggest that glial CS helps to promote neurite growth and, more importantly, they indicate that a HS proteoglycan is, at least, partially responsible for the non-permissive role of the midline glia to the growth of midbrain neurites.

Effects of neonatal cerebral hypoxia-ischemia on the in vitro phosphorylation of synapsin 1 in rat synaptosomes.

Synapsins are phosphoproteins related to the anchorage of synaptic vesicles to the actin skeleton. Hypoxia-ischemia causes an increased calcium influx into neurons through ionic channels gated by activation of glutamate receptors. In this work seven-day-old Wistar rats were submitted to hypoxia-ischemia and sacrificed after 21 hours, 7, 30, or 90 days. Synaptosomal fractions were obtained by Percoll gradients and incubated with 32P (10 microCi/g). Proteins were analysed by SDS-PAGE and radioactivity incorporated into synapsin 1 was counted by liquid scintillation. Twenty-one hours after hypoxia-ischemia we observed a reduction on the in vitro phosphorylation of synapsin 1, mainly due to hypoxia, rather than to ischemia; this effect was reversed at day 7 after the insult. There was another decrease in phosphorylation 30 days after the event interpreted as a late effect of hypoxia-ischemia. No changes were observed at day 90. Our results suggest that decreased phosphorylation of synapsin 1 could be related to neuronal death that follows hypoxia-ischemia.

Effects of jarastatin, a novel snake venom disintegrin, on neutrophil migration and actin cytoskeleton dynamics.

A new disintegrin, an RGD-containing peptide of 6 kDa called jarastatin, was purified from Bothrops jararaca venom. It is a potent inhibitor of platelet aggregation induced by ADP, collagen, and thrombin. The effect of jarastatin on neutrophil migration in vivo and in vitro and on the actin cytoskeleton dynamics of these cells was investigated. Incubation in vitro with jarastatin significantly inhibited, in a concentration-dependent manner, the chemotaxis of human neutrophils toward fMLP, IL-8, and jarastatin itself. Despite this inhibitory effect, jarastatin induced neutrophil chemotaxis. A significant increase of F-actin content was observed in jarastatin-treated neutrophils. Furthermore, as demonstrated by confocal microscopy after FITC-phalloidin labeling, these cells accumulated F-actin at the plasmalemma, a distribution similar to that observed in fMLP-stimulated cells. Pretreatment of mice with jarastatin inhibited neutrophil migration into peritoneal cavities induced by carrageenan injection. The results suggest that binding of jarastatin to neutrophil integrins promotes cellular activation and triggers a dynamic alteration of the actin filament system and that this is one of the first event in integrin-mediated signaling.