Antimetastatic Potential of PAI-1 Specific RNA Aptamers

The serine protease inhibitor plasminogen activator inhibitor-1 (PAI-1) is increased in several cancers, including breast, where it is associated with a poor outcome. Metastatic breast cancer has a dismal prognosis, as evidenced by treatment goals that are no longer curative but are largely palliative in nature. PAI-1 competes with integrins and the urokinase plasminogen activator receptor on the surface of breast cancer cells for binding to vitronectin. This results in the detachment of tumor cells from the extracellular matrix, which is critical to the metastatic process. For this reason, we sought to isolate RNA aptamers that disrupt the interaction between PAI-1 and vitronectin. Through utilization of combinatorial chemistry techniques, aptamers have been selected that bind to PAI-1 with high affinity and specificity. We identified two aptamers, WT-15 and SM-20, that disrupt the interactions between PAI-1 and heparin, as well as PAI-1 and vitronectin, without affecting the antiprotease activity of PAI-1. Furthermore, SM-20 prevented the detachment of breast cancer cells (MDA-MB-231) from vitronectin in the presence of PAI-1, resulting in an increase in cellular adhesion. Therefore, the PAI-1 aptamer SM-20 demonstrates therapeutic potential as an antimetastatic agent and could possibly be used as an adjuvant to traditional chemotherapy for breast cancer.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78126/1/oli.2008.0177.pd

Cinética de fermentação ruminal de silagens de milheto Ruminal fermentation kinetics of pearl millet silages

Avaliaram-se a degradabilidade da matéria seca e a cinética de fermentação ruminal das silagens de três genótipos de milheto (BRS-1501, NPM-1 e CMS-3), por meio da técnica in vitro semi-automática de produção de gases. O delineamento experimental utilizado foi o de blocos ao acaso em arranjo de parcelas subdivididas. Para a comparação dos genótipos, foi utilizado o teste SNK (P<0,05), e os parâmetros da cinética de fermentação foram ajustados ao modelo unicompartimental de France. A partir de 24 horas, a silagem do genótipo BRS-1501 foi a que apresentou maior produção acumulativa de gases. Os valores de degradabilidade da matéria seca apresentados às 96 horas de fermentação foram de 53,9% para a silagem do BRS-1501, 51,7% para a silagem do CMS-3 e 49,1% para a silagem do NPM-1, sendo este o material com menor degradabilidade (P<0,05). Os potenciais máximos de produção de gases variaram de 145,18 para o genótipo CMS-3 a 155,02ml/g de MS para o BRS-1501. A silagem do genótipo BRS-1501 destacou-se entre as demais, em função do seu maior potencial de produção de gases e degradabilidades efetivas.<br>The dry matter digestibility and the fermentation kinetics of three pearl millet genotypes silages (BRS-1501, NPM-1, and CMS-3) were estimated by the semi-automated in vitro gas production technique, using a completely randomized blocks design in a split plot arrangement. The genotypes means were compared by SNK test (P<0.05) and fermentation kinetics parameters estimated by regression of gas production on time using the France model. The greater cumulative gas production from 24 hours on was obtained by BRS-1501 genotype silage. The dry matter degradability (DMD) values at 96 hours of incubation were 53.9% for BRS-1501, 51.7% for NPM-1, and 49.1% for CMS-3 silage. The lowest DMD (P<0.05) among the studied genotypes silages was observed for CMS-3 silage. The maximum potential of gas production ranged from 145.18ml/g of dry matter for CMS-3 genotype silage to 155.02ml/g of dry matter for BRS-1501 silage. The BRS-1501 genotype silage showed the highest potential of gas production and effective degradabilities

Brachiaria spp. poisoning of ruminants in Brazil

Brachiaria species are the most important grasses for cattle production in Brazil. However, a limiting factor for the use of Brachiaria spp. is their toxicity. Most outbreaks of hepatogenous photosensitization are caused by B. decumbens; however B. brizantha, B. humidicola and B. ruziziensis can also cause poisoning. The poisoning affects cattle, sheep, goats and buffalo. Sheep are more susceptible than other animal species and the young are more susceptible than adults. There are differences in susceptibility among animals of the same species and it has been suggested that this resistance is genetic. Also has been suggested that buffalo and probably some sheep are resilient, i.e. when poisoned these animals have histologic lesions and high GGT serum concentrations, but do not show clinical signs. In general, saponin concentrations are higher in growing plants, but outbreaks occur all over the year, probably due to unexplained rise in saponin concentration in the plant. A clinical syndrome of progressive weight loss and death, without photosensitization, has been reported in cattle poisoned by B. decumbens. Main preventive measures are based on the selection of resistant or resilient animals and on the development of Brachiaria species or varieties with low saponin concentration

Long-term outcomes after transcatheter aortic valve implantation in failed bioprosthetic valves

.Aims: Due to bioprosthetic valve degeneration, aortic valve-in-valve (ViV) procedures are increasingly performed. There are no data on long-term outcomes after aortic ViV. Our aim was to perform a large-scale assessment of long-term survival and reintervention after aortic ViV. Methods and results: A total of 1006 aortic ViV procedures performed more than 5 years ago [mean age 77.7 \ub1 9.7 years; 58.8% male; median STS-PROM score 7.3% (4.2-12.0)] were included in the analysis. Patients were treated with Medtronic self-expandable valves (CoreValve/Evolut, Medtronic Inc., Minneapolis, MN, USA) (n = 523, 52.0%), Edwards balloon-expandable valves (EBEV, SAPIEN/SAPIEN XT/SAPIEN 3, Edwards Lifesciences, Irvine, CA, USA) (n = 435, 43.2%), and other devices (n = 48, 4.8%). Survival was lower at 8 years in patients with small-failed bioprostheses [internal diameter (ID) 64 20 mm] compared with those with large-failed bioprostheses (ID &gt; 20 mm) (33.2% vs. 40.5%, P = 0.01). Independent correlates for mortality included smaller-failed bioprosthetic valves [hazard ratio (HR) 1.07 (95% confidence interval (CI) 1.02-1.13)], age [HR 1.21 (95% CI 1.01-1.45)], and non-transfemoral access [HR 1.43 (95% CI 1.11-1.84)]. There were 40 reinterventions after ViV. Independent correlates for all-cause reintervention included pre-existing severe prosthesis-patient mismatch [subhazard ratio (SHR) 4.34 (95% CI 1.31-14.39)], device malposition [SHR 3.75 (95% CI 1.36-10.35)], EBEV [SHR 3.34 (95% CI 1.26-8.85)], and age [SHR 0.59 (95% CI 0.44-0.78)]. Conclusions: The size of the original failed valve may influence long-term mortality, and the type of the transcatheter valve may influence the need for reintervention after aortic ViV

The Biology of the Presenilin Complexes

APP proteolytic processing Alzheimer's Disease (AD) is characterized by the deposition of two kinds of abnormal protein aggregates, senile plaques and neurofibrillary tangles, and by neuronal dysfunction and cell loss in the brain. Senile plaques are primarily composed of extracellular deposits of hydrophobic 37-43 amino acid Aβ peptides. Aβ peptides are derived by successive enzymatic cleavages of the type I membrane protein, β-amyloid precursor protein (APP) (Haass and Selkoe 1993). APP is first cleaved close to the membrane in the extracellular domain by either α-or β-secretase, resulting in a release of soluble APP ectodomains, and residual membrane-tethered C-terminal protein stubs, termed C83 or C99, respectively (The numbers indicate the length of each carboxylterminal fragment). C83 and C99 are substrates for γ-secretase, an activity that generates p3 and Aβ peptides, respectively. γ-Secretase processes substrates at different positions within the membrane domain and thus, both Aβ and p3 have "ragged" termini. Aβ has been best studied in this regard and species between 37 and 43 amino acid residues have been identified. γ-Secretase cleavage of APP also releases the intracellular carboxy-terminal "APP intracellular domain" or "AICD". The function of both Aβ and AICD is the subject of intense investigations. Because Aβ42 is the primary constituent of the amyloid fibrils deposited in the AD brains, and mutations in APP and presenilin enhance the production of this peptide, γ-secretase cleavage of APP is a pivotal step in AD pathogenesis. It is striking that this proteolytic reaction occurs within the highly hydrophobic environment of the membrane. Identification of presenilin Genetic studies in familial AD (FAD) cases have identified disease-linked mutations in three genes that contribute to AD. The first pathogenic mutations in early-onset FAD families were found in the APP gene on chromosome 21 (Chartier-Harlin et al. 1991; Goate et al. 1991; Murrell et al. 1991). However, subsequent studies indicated that mutations in APP account only for a small fraction of FAD cases. Several genetic studies indicated a major locus for FAD on chromosome 14 in early onset autosomal dominant AD, and in 1995, the Presenilin1 (PS1) gene on chromosome 14 (14q24.3) was identified by positional cloning (Sherrington et al. 1995). Shortly thereafter, it was shown that mutations in the closely related PS2 gene on chromosome 1 (1q42.2) could cause FAD as well (Levy-Lahad et al. 1995; Rogaev et al. 1995). Studies in transgenic mice (Borchelt et al. 1996; Duff et al. 1996) and cultured cells (Citron et al. 1997; Scheuner et al. 1996; Tomita et al. 1997) have revealed that expression of FAD-linked PS variants elevates Aβ42/Aβ40 ratios. Moreover, transgenic mice that co-express FAD-mutant PS1 and APP develop amyloid plaques much earlier than age-matched mutant APP mice (Borchelt et al. 1997). Therefore, PS mutations cause a change in the Aβ42/40 ratio, but whether PS is directly involved in γ-secretase processing of APP was unclear. However, in PS-deficient neurons and fibroblasts, APP processing was greatly impaired, leading to the accumulation of the C83 and C99 APP fragments, the direct substrates of γ-secretase, and inhibition of Aβ (and p3) generation (De Strooper et al. 1998; Xia et al. 1998). Thus, PS are directly required for γ-secretase cleavage of APP. Overall, the findings imply that mutations in the substrate (APP) or in the proteolytic machinery (PS) result in similar changes in Aβ42 generation (Scheuner et al. 1996). This provides very strong support for the "amyloid cascade hypothesis". © 2007 Springer Science+Business Media, LLC. All rights reserved