252 resultados para morphology factor
Resumo:
PURPOSE: To analyze components of the deposits in the corneal flap interface of granular corneal dystrophy type II (GCD II) patients after laser in situ keratomileusis (LASIK). METHODS: Four corneal GCD II specimens displaying disease exacerbation after LASIK were analyzed. Three of these specimens included the recipient corneal button after penetrating keratoplasty or deep lamellar keratoplasty for advanced GCD II after LASIK. The fourth specimen, a similar case of GCD II after LASIK, included the amputated corneal flap. Specimens were processed for histopathologic and immunohistochemical analyses. RESULTS: Corneal stromal deposits in the LASIK flaps of all specimens were stained with 3 anti-transforming growth factor-beta-induced protein (TGFBIp) antibodies. The deposits displayed bright red color staining with Masson trichrome; however, negative staining was seen with Congo red, suggesting that hyaline is the main component localizing to the TGFBIp deposits rather than amyloid. CONCLUSIONS: Amorphous granular material deposited along the interface of the LASIK flap in GCD II corneas is composed mainly of hyaline deposits.
Resumo:
Pollination syndromes involve convergent evolution towards phenotypes composed of specific scents, colours or floral morphologies that attract or restrict pollinator access to reward. How these traits might influence the distributions of plant species in interaction with pollinators has rarely been investigated. We sampled 870 vegetation plots in the western Swiss Alps and classified the plant species into seven blossom types according to their floral morphology (wind, disk, funnel, tube, bilabiate, head or brush). We investigated the environmental features of plots with functional diversity (FD) lower than expected by chance alone to detect potential pollination filtering and related the proportions of the seven blossom types to a combination of environmental descriptors. From these results, we inferred the potential effect of the pollinator on the spatial distribution of plant species. The vegetation plots with significantly lower FD of blossom types than expected by chance were found at higher altitudes, and the proportions of blossom types were strongly patterned along the same gradient. These results support a biotic filtering effect on plant species assemblages through pollination: disk blossoms became dominant at higher altitudes, resulting in a lower FD. In harsh conditions at high altitudes, pollinators usually decrease in activity, and the openness of the disk blossom grants access to any available pollinator. Inversely, bilabiate blossoms, which are mostly pollinated by bees, were more abundant at lower elevations, which are characterised by greater abundance and diversity of bees. Generalisation through openness of the blossom could be advantageous at high elevations, while specialisation could be a successful alternative strategy at lower elevations. The approach used in this study is purely correlative, and further investigations should be conducted to infer the nature of the causal relationship between plant and pollinator distributions.
Resumo:
PR0X1 est un facteur de transcription très conservé au cours de l'évolution. PROX1 joue un rôle essentiel dans de nombreuses étapes de l'embryogenèse, telles que le développement du système lymphatique ou la migration des hépatocytes. Récemment, il a été démontré que PROX1 contribue à la progression des tumeurs colorectales, en tant que gène cible de la voie de signalisation Wnt. En utilisant des approches de co- immunoprécipitation et de ligature de proximité, nous avons trouvé que PROX1 fait également partie du complexe transcriptionnel TCF/ß-catenin, à la fois dans les cellules humaines de cancer du colon et dans les cellules murines de l'épithélium de l'intestin, dans lesquelles la voie de signalisation Wnt est activée. Dans le but de comprendre le mécanisme d'action de PROX1, nous avons analysé le génome des cellules cancéreuses de colon à la recherche des sites de fixation de PROX1, TCF4 et ß-catenin. Nous avons ainsi pu montrer que TCF4, ß-catenin et PROX1 se fixent simultanément sur une sous- population d'amplificateurs génomiques, sur lesquels PROX1 agit comme répresseur. Ces résultats suggèrent que, spécifiquement dans le cadre du cancer du colon, PROX1 agit en tant que modificateur de la voie de transduction du signal Wnt/ß-catenin. De plus, nous proposons que ceci constitue un des mécanismes par lesquels la signalisation durable de Wnt, qui est observée dans la majorité des cancers du colon, transforme le programme génétique des progéniteurs intestinaux, initialement normal, en output spécifique de ce type de cancers, ce qui contribue plus tard à la croissance infinie de la tumeur, à son caractère invasif et à sa dissémination.
Resumo:
Objective. To study the impact of the neutral endopeptidase (NEP)/neuropeptides (NPs) axis and nuclear factor kappa B (NFκB) as predictors of prostate-specific antigen (PSA) recurrence after radical prostatectomy (RP). Patients and Methods. 70 patients with early-stage PC were treated with RP and their tumor samples were evaluated for expression of NEP, endothelin-1 (ET-1) and NFκB (p65). Time to PSA recurrence was correlated with the examined parameters and combined with preoperative PSA level, Gleason score, pathological TNM (pT) stage, and surgical margin (SM) assessment. Results and Limitations. Membranous expression of NEP (P < 0.001), cytoplasmic ET-1 (P = 0.002), and cytoplasmic NFκB (P < 0.001) were correlated with time to PSA relapse. NEP was associated with ET-1 (P < 0.001) and NFκB (P < 0.001). ET-1 was also correlated with NFκB (P < 0.001). NEP expression (P = 0.017), pT stage (P = 0.013), and SMs (P = 0.036) were independent predictors of time to PSA recurrence. Conclusions. There seems to be a clinical model of NEP/NPs and NFκB pathways interconnection, with their constituents following inverse patterns of expression in accordance with their biological roles and molecular interrelations.
Resumo:
BACKGROUND CONTEXT: Studies involving factor analysis (FA) of the items in the North American Spine Society (NASS) outcome assessment instrument have revealed inconsistent factor structures for the individual items. PURPOSE: This study examined whether the factor structure of the NASS varied in relation to the severity of the back/neck problem and differed from that originally recommended by the developers of the questionnaire, by analyzing data before and after surgery in a large series of patients undergoing lumbar or cervical disc arthroplasty. STUDY DESIGN/SETTING: Prospective multicenter observational case series. PATIENT SAMPLE: Three hundred ninety-one patients with low back pain and 553 patients with neck pain completed questionnaires preoperatively and again at 3 to 6 and 12 months follow-ups (FUs), in connection with the SWISSspine disc arthroplasty registry. OUTCOME MEASURES: North American Spine Society outcome assessment instrument. METHODS: First, an exploratory FA without a priori assumptions and subsequently a confirmatory FA were performed on the 17 items of the NASS-lumbar and 19 items of the NASS-cervical collected at each assessment time point. The item-loading invariance was tested in the German version of the questionnaire for baseline and FU. RESULTS: Both NASS-lumbar and NASS-cervical factor structures differed between baseline and postoperative data sets. The confirmatory analysis and item-loading invariance showed better fit for a three-factor (3F) structure for NASS-lumbar, containing items on "disability," "back pain," and "radiating pain, numbness, and weakness (leg/foot)" and for a 5F structure for NASS-cervical including disability, "neck pain," "radiating pain and numbness (arm/hand)," "weakness (arm/hand)," and "motor deficit (legs)." CONCLUSIONS: The best-fitting factor structure at both baseline and FU was selected for both the lumbar- and cervical-NASS questionnaires. It differed from that proposed by the originators of the NASS instruments. Although the NASS questionnaire represents a valid outcome measure for degenerative spine diseases, it is able to distinguish among all major symptom domains (factors) in patients undergoing lumbar and cervical disc arthroplasty; overall, the item structure could be improved. Any potential revision of the NASS should consider its factorial structure; factorial invariance over time should be aimed for, to allow for more precise interpretations of treatment success.
Resumo:
BACKGROUND:: Mechanical stretch has been shown to induce vascular remodeling and increase vessel density, but the pathophysiologic mechanisms and the morphologic changes induced by tensile forces to dermal vessels are poorly understood. METHODS:: A custom computer-controlled stretch device was designed and applied to the backs of C57BL/6 mice (n = 38). Dermal and vascular remodeling was studied over a 7-day period. Corrosion casting and three-dimensional scanning electron microscopy and CD31 staining were performed to analyze microvessel morphology. Hypoxia was assessed by immunohistochemistry. Western blot analysis of vascular endothelial growth factor (VEGF) and mRNA expression of VEGF receptors was performed. RESULTS:: Skin stretching was associated with increased angiogenesis as demonstrated by CD31 staining and vessel corrosion casting where intervascular distance and vessel diameter were decreased (p < 0.01). Immediately after stretching, VEGF dimers were increased. Messenger RNA expression of VEGF receptor 1, VEGF receptor 2, neuropilin 1, and neuropilin 2 was increased starting as early as 2 hours after stretching. Highly proliferating epidermal cells induced epidermal hypoxia starting at day 3 (p < 0.01). CONCLUSIONS:: Identification of significant hypoxic cells occurred after identification of neovessels, suggesting an alternative mechanism. Increased expression of angiogenic receptors and stabilization of VEGF dimers may be involved in a mechanotransductive, prehypoxic induction of neovascularization.
Resumo:
BACKGROUND: Human immunodeficiency virus (HIV) takes advantage of multiple host proteins to support its own replication. The gene ZNRD1 (zinc ribbon domain-containing 1) has been identified as encoding a potential host factor that influenced disease progression in HIV-positive individuals in a genomewide association study and also significantly affected HIV replication in a large-scale in vitro short interfering RNA (siRNA) screen. Genes and polymorphisms identified by large-scale analysis need to be followed up by means of functional assays and resequencing efforts to more precisely map causal genes. METHODS: Genotyping and ZNRD1 gene resequencing for 208 HIV-positive subjects (119 who experienced long-term nonprogression [LTNP] and 89 who experienced normal disease progression) was done by either TaqMan genotyping assays or direct sequencing. Genetic association analysis was performed with the SNPassoc package and Haploview software. siRNA and short hairpin RNA (shRNA) specifically targeting ZNRD1 were used to transiently or stably down-regulate ZNRD1 expression in both lymphoid and nonlymphoid cells. Cells were infected with X4 and R5 HIV strains, and efficiency of infection was assessed by reporter gene assay or p24 assay. RESULTS: Genetic association analysis found a strong statistically significant correlation with the LTNP phenotype (single-nucleotide polymorphism rs1048412; [Formula: see text]), independently of HLA-A10 influence. siRNA-based functional analysis showed that ZNRD1 down-regulation by siRNA or shRNA impaired HIV-1 replication at the transcription level in both lymphoid and nonlymphoid cells. CONCLUSION: Genetic association analysis unequivocally identified ZNRD1 as an independent marker of LTNP to AIDS. Moreover, in vitro experiments pointed to viral transcription as the inhibited step. Thus, our data strongly suggest that ZNRD1 is a host cellular factor that influences HIV-1 replication and disease progression in HIV-positive individuals.
Resumo:
Inhibition of coagulation factor XII (FXII) activity represents an attractive approach for the treatment and prevention of thrombotic diseases. The few existing FXII inhibitors suffer from low selectivity. Using phage display combined to rational design, we developed a potent inhibitor of FXII with more than 100-fold selectivity over related proteases. The highly selective peptide macrocycle is a promising candidate for the control of FXII activity in antithrombotic therapy and a valuable tool in hematology research.
Resumo:
The macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that recently emerged as an attractive therapeutic target for a variety of diseases. A diverse panel of fully human anti-MIF antibodies was generated by selection from a phage display library and extensively analyzed in vitro. Epitope mapping studies identified antibodies specific for linear as well as structural epitopes. Experimental animal studies revealed that only those antibodies binding epitopes within amino acids 50-68 or 86-102 of the MIF molecule exerted protective effects in models of sepsis or contact hypersensitivity. Within the MIF protein, these two binding regions form a β-sheet structure that includes the MIF oxidoreductase motif. We therefore conclude that this β-sheet structure is a crucial region for MIF activity and a promising target for anti-MIF antibody therapy.
Resumo:
Addition of insulin, IGF I or IGF II to serum-free cultures of fetal rat brain cells (gestation day 15/16) significantly stimulates DNA synthesis. The dose-response curves show that IGF I is more potent than insulin; half maximal stimulation of [3H]thymidine incorporation is obtained at about 0.4 nM IGF I and 14 nM insulin, respectively. Cultures initiated 2 days later (gestation day 17/18) showed a decreased responsiveness to both peptides. No additive effect was observed after combined addition of both peptides at near-maximal doses. Both peptides show a latency of action of about 12-18 h. In the presence of either IGF or insulin, neuronal as well as glial enzymes are increased, suggesting that neuronal and glial precursor cell division is influenced. IGF I and IGF II interact with a specific binding site for which insulin competes very weakly; however IGF I and IGF II bind with relatively high affinity to the insulin specific binding site. The present results support the hypothesis that both insulin and IGF stimulate mitotic activity by interacting with specific somatomedin receptors and suggest a physiological role of IGF in the developing brain.
Resumo:
BACKGROUND: Lapatinib is an effective anti-HER2 therapy in advanced breast cancer and docetaxel is one of the most active agents in breast cancer. Combining these agents in pre-treated patients with metastatic disease had previously proved challenging, so the primary objective of this study aimed to determine the maximum tolerated dose (MTD) in treatment-naive patients, by identifying acute dose-limiting toxicities (DLT) during cycle 1 in the first part of a phases 1-2 neoadjuvant European Organisation for Research and Treatment of Cancer (EORTC) trial. PATIENTS AND METHODS: Patients with large operable or locally-advanced HER2 positive breast cancer were treated with continuous lapatinib, and docetaxel every 21days for 4 cycles. Dose levels (DLs) were: 1000/75, 1250/75, 1000/85, 1250/85, 1000/100 and 1250/100 (mg/day)/(mg/m(2)). RESULTS: Twenty-one patients were included. Two DLTs occurred at dose level 5 (1000/100); one grade 4 neutropenia ⩾7days and one febrile neutropenia. A further 3 patients were therefore treated at the same dose with prophylactic granulocyte-colony stimulating factor (G-CSF), and 3 patients at dose level 6. No further DLTs were observed. CONCLUSIONS: Our recommended dose for phase II is lapatinib 1000mg/day and docetaxel 100mg/m(2) with G-CSF in HER2 positive non-metastatic breast cancer. The dose of lapatinib should have been 1250mg/day but we were mindful of the high rate of treatment discontinuation in GeparQuinto with lapatinib 1250mg/day combined with docetaxel. No grade 3-4 diarrhoea was observed. Pharmacodynamics analysis suggests that concomitant medications altering P-glycoprotein activity (in addition to lapatinib) can modify toxicity, including non-haematological toxicities. This needs verification in larger trials, where it may contribute to understanding the sources of variability in clinical toxicity and treatment discontinuation.
Resumo:
Introduction: Quantitative measures of degree of lumbar spinal stenosis (LSS) such as antero-posterior diameter of the canal or dural sac cross sectional area vary widely and do not correlate with clinical symptoms or results of surgical decompression. In an effort to improve quantification of stenosis we have developed a grading system based on the morphology of the dural sac and its contents as seen on T2 axial images. The grading comprises seven categories ranging form normal to the most severe stenosis and takes into account the ratio of rootlet/CSF content. Material and methods: Fifty T2 axial MRI images taken at disc level from twenty seven symptomatic lumbar spinal stenosis patients who underwent decompressive surgery were classified into seven categories by five observers and reclassified 2 weeks later by the same investigators. Intra- and inter-observer reliability of the classification were assessed using Cohen's and Fleiss' kappa statistics, respectively. Results: Generally, the morphology grading system itself was well adopted by the observers. Its success in application is strongly influenced by the identification of the dural sac. The average intraobserver Cohen's kappa was 0.53 ± 0.2. The inter-observer Fleiss' kappa was 0.38 ± 0.02 in the first rating and 0.3 ± 0.03 in the second rating repeated after two weeks. Discussion: In this attempt, the teaching of the observers was limited to an introduction to the general idea of the morphology grading system and one example MRI image per category. The identification of the dimension of the dural sac may be a difficult issue in absence of complete T1 T2 MRI image series as it was the case here. The similarity of the CSF to possibly present fat on T2 images was the main reason of mismatch in the assignment of the cases to a category. The Fleiss correlation factors of the five observers are fair and the proposed morphology grading system is promising.
Resumo:
HTPSELEX is a public database providing access to primary and derived data from high-throughput SELEX experiments aimed at characterizing the binding specificity of transcription factors. The resource is primarily intended to serve computational biologists interested in building models of transcription factor binding sites from large sets of binding sequences. The guiding principle is to make available all information that is relevant for this purpose. For each experiment, we try to provide accurate information about the protein material used, details of the wet lab protocol, an archive of sequencing trace files, assembled clone sequences (concatemers) and complete sets of in vitro selected protein-binding tags. In addition, we offer in-house derived binding sites models. HTPSELEX also offers reasonably large SELEX libraries obtained with conventional low-throughput protocols. The FTP site contains the trace archives and database flatfiles. The web server offers user-friendly interfaces for viewing individual entries and quality-controlled download of SELEX sequence libraries according to a user-defined sequencing quality threshold. HTPSELEX is available from ftp://ftp.isrec.isb-sib.ch/pub/databases/htpselex/ and http://www.isrec.isb-sib.ch/htpselex.
Resumo:
Mutations in the epithelial morphogen ectodysplasin-A (EDA), a member of the tumor necrosis factor (TNF) family, are responsible for the human disorder X-linked hypohidrotic ectodermal dysplasia (XLHED) characterized by impaired development of hair, eccrine sweat glands, and teeth. EDA-A1 and EDA-A2 are two splice variants of EDA, which bind distinct EDA-A1 and X-linked EDA-A2 receptors. We identified a series of novel EDA mutations in families with XLHED, allowing the identification of the following three functionally important regions in EDA: a C-terminal TNF homology domain, a collagen domain, and a furin protease recognition sequence. Mutations in the TNF homology domain impair binding of both splice variants to their receptors. Mutations in the collagen domain can inhibit multimerization of the TNF homology region, whereas those in the consensus furin recognition sequence prevent proteolytic cleavage of EDA. Finally, a mutation affecting an intron splice donor site is predicted to eliminate specifically the EDA-A1 but not the EDA-A2 splice variant. Thus a proteolytically processed, oligomeric form of EDA-A1 is required in vivo for proper morphogenesis.
Resumo:
The interpretation of the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) is based on a 4-factor model, which is only partially compatible with the mainstream Cattell-Horn-Carroll (CHC) model of intelligence measurement. The structure of cognitive batteries is frequently analyzed via exploratory factor analysis and/or confirmatory factor analysis. With classical confirmatory factor analysis, almost all crossloadings between latent variables and measures are fixed to zero in order to allow the model to be identified. However, inappropriate zero cross-loadings can contribute to poor model fit, distorted factors, and biased factor correlations; most important, they do not necessarily faithfully reflect theory. To deal with these methodological and theoretical limitations, we used a new statistical approach, Bayesian structural equation modeling (BSEM), among a sample of 249 French-speaking Swiss children (8-12 years). With BSEM, zero-fixed cross-loadings between latent variables and measures are replaced by approximate zeros, based on informative, small-variance priors. Results indicated that a direct hierarchical CHC-based model with 5 factors plus a general intelligence factor better represented the structure of the WISC-IV than did the 4-factor structure and the higher order models. Because a direct hierarchical CHC model was more adequate, it was concluded that the general factor should be considered as a breadth rather than a superordinate factor. Because it was possible for us to estimate the influence of each of the latent variables on the 15 subtest scores, BSEM allowed improvement of the understanding of the structure of intelligence tests and the clinical interpretation of the subtest scores.