927 resultados para least median of squares
Resumo:
Background Autologous chondrocyte implantation is a cell therapeutic approach for the treatment of chondral and osteochondral defects in the knee joint. The authors previously reported on the histologic and radiologic outcome of autologous chondrocyte implantation in the short- to midterm, which yields mixed results. Purpose The objective is to report on the clinical outcome of autologous chondrocyte implantation for the knee in the midterm to long term. Study Design Cohort study; Level of evidence, 3. Methods Eighty patients who had undergone autologous chondrocyte implantation of the knee with mid- to long-term follow-up were analyzed. The mean patient age was 34.6 years (standard deviation, 9.1 years), with 63 men and 17 women. Seventy-one patients presented with a focal chondral defect, with a median defect area of 4.1 cm2 and a maximum defect area of 20 cm2. The modified Lysholm score was used as a self-reporting clinical outcome measure to determine the following: (1) What is the typical pattern over time of clinical outcome after autologous chondrocyte implantation; and (2) Which patient-related predictors for the clinical outcome pattern can be used to improve patient selection for autologous chondrocyte implantation? Results The average follow-up time was 5 years (range, 2.7–9.3). Improvement in clinical outcome was found in 65 patients (81%), while 15 patients (19%) showed a decline in outcome. The median preoperative Lysholm score of 54 increased to a median of 78 points. The most rapid improvement in Lysholm score was over the 15-month period after operation, after which the Lysholm score remained constant for up to 9 years. The authors were unable to identify any patient-specific factors (ie, age, gender, defect size, defect location, number of previous operations, preoperative Lysholm score) that could predict the change in clinical outcome in the first 15 months. Conclusion Autologous chondrocyte implantation seems to provide a durable clinical outcome in those patients demonstrating success at 15 months after operation. Comparisons between other outcome measures of autologous chondrocyte implantation should be focused on the clinical status at 15 months after surgery. The patient-reported clinical outcome at 15 months is a major predictor of the mid- to long-term success of autologous chondrocyte implantation.
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There may be circumstances where it is necessary for microbiologists to compare variances rather than means, e,g., in analysing data from experiments to determine whether a particular treatment alters the degree of variability or testing the assumption of homogeneity of variance prior to other statistical tests. All of the tests described in this Statnote have their limitations. Bartlett’s test may be too sensitive but Levene’s and the Brown-Forsythe tests also have problems. We would recommend the use of the variance-ratio test to compare two variances and the careful application of Bartlett’s test if there are more than two groups. Considering that these tests are not particularly robust, it should be remembered that the homogeneity of variance assumption is usually the least important of those considered when carrying out an ANOVA. If there is concern about this assumption and especially if the other assumptions of the analysis are also not likely to be met, e.g., lack of normality or non additivity of treatment effects then it may be better either to transform the data or to carry out a non-parametric test on the data.
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Fathers in the United Kingdom (UK) usually attend the birth and immediate care of their baby. They also have an increasing presence during complicated and preterm childbirth, newborn resuscitation and early neonatal unit(NNU) care. However, there is limited evidence about the effect of these experiences on them. The aim of this study was to gain an understanding of the experiences of fathers encountering these situations. The study consisted of three phases and was undertaken in one National Health Service trust in the UK. Qualitative semi-structured interviews using a phenomenological approach were undertaken with 20 first-time fathers present at the delivery, resuscitation and/or admission of their baby to the NNU. Direct observations were made of 22 normal and complicated deliveries and initial newborn care and qualitative semi-structured interviews using the critical incident approach were undertaken with 37 health care professionals (HCPs). The study generated qualitative and quantitative data that were analysed accordingly. The findings show that most fathers were involved for at least some of the time and often spontaneously initiated their involvement. Their most important need was for information. They were usually more concerned about their partner, irrespective of the baby?s need for resuscitation and NNU care. To facilitate their involvement, fathers needed guidance and support from HCPs, particularly delivery suite midwives. Most HCPs recognised the needs of fathers and ways in which they could be helped to connect with their experience. However, these needs were not always met, usually because of inadequate staffing levels, a lack of resources or a mother-centred philosophy of care. The findings suggest the service often determines the extent to which fathers are involved. It is anticipated that these findings will inform HCP education and training and the development of both policy and health education thereby enhancing the quality of care provision for fathers.
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Elevated levels of the calcium-binding protein S100A4 promote metastasis and in carcinoma cells are associated with reduced survival of cancer patients. S100A4 interacts with target proteins that affect a number of activities associated with metastatic cells. However, it is not known how many of these interactions are required for S100A4-promoted metastasis, thus hampering the design of specific inhibitors of S100A4-induced metastasis. Intracellular S100A4 exists as a homodimer through previously identified, well conserved, predominantly hydrophobic key contacts between the subunits. Here it is shown that mutating just one key residue, phenylalanine 72, to alanine is sufficient to reduce the metastasis-promoting activity of S100A4 to 50% that of the wild type protein, and just 2 or 3 specific mutations reduces the metastasis-promoting activity of S100A4 to less than 20% that of the wild type protein. These mutations inhibit the self-association of S100A4 in vivo and reduce markedly the affinity of S100A4 for at least two of its protein targets, a recombinant fragment of non-muscle myosin heavy chain isoform A, and p53. Inhibition of the self-association of S100 proteins might be a novel means of inhibiting their metastasis-promoting activities.
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Inadequate blood flow to an organ, ischaemia, may lead to both local and remote tissue injury characterized by oedema, increased microvascular permeability to protein and degradation of connective tissue components. This damage is probably caused by the accumulation and inappropriate activation of neutrophils which occurs when the tissue is reperfused. To test this hypothesis a number of in vitro models of the sequential stages of ischaemia/reperfusion injury were examined. Methods were initially developed to examine the adhesion of neutrophils to monolayers of a cultured endothelial cell line (ECV304) after periods of hypoxia and reoxygenation. Neutrophil migration in response to factors secreted by the treated endothelial cells was then assessed. The genesis of an inappropriate oxidative burst by the neutrophil upon exposure to endothelial chemoattractants and adhesion molecules was also measured. Finally to appraise how tissue function might be affected by endothelial cell hypoxia the contractility of vascular smooth muscle was examined. Neutrophil adhesion to ECV304 cells, which had been hypoxic for 4 hours and then reoxygenated for 30 minutes, was significantly increased. This response was probably initiated by reactive oxygen species (ROS) generated by the endothelial cells. Blockage of their production by allopurinol reduced the heightened adhesion. Similarly removal of ROS by superoxide dismutase or catalase also attenuated adhesion. ROS generation in turn caused the release of a soluble factor (s) which induced a conformational change on the neutrophil surface allowing it to bind to the intercellular adhesion molecule 1 (ICAM-1) on the endothelial cell. Soluble factor (s) from hypoxia/reoxygenated endothelial cells also had a powerful neutrophil chemoattractant ability. When neutrophils were exposed to both hypoxic/reoxygenated endothelial cells and the soluble factor (s) released by them a large oxidative burst was elicited. This response was greatest immediately after reoxygenation and one hour later was diminishing suggesting at least one of the components involved was labile. Analysis of the supernatant from hypoxic/reoxygenated endothelial cell cultures and studies using inhibitors of secretion suggested platelet activating factor (PAF) may be a major component in this overall sequence of events. Lesser roles for IL-8, TNF and LTB4 were also suggested. The secretory products from hypoxia/reoxygenated endothelial cells also affected smooth muscle contractility having an anti-vasoconstrictor or relaxation property, similar to that exerted by PAF.
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This thesis demonstrates that the use of finite elements need not be confined to space alone, but that they may also be used in the time domain, It is shown that finite element methods may be used successfully to obtain the response of systems to applied forces, including, for example, the accelerations in a tall structure subjected to an earthquake shock. It is further demonstrated that at least one of these methods may be considered to be a practical alternative to more usual methods of solution. A detailed investigation of the accuracy and stability of finite element solutions is included, and methods of applications to both single- and multi-degree of freedom systems are described. Solutions using two different temporal finite elements are compared with those obtained by conventional methods, and a comparison of computation times for the different methods is given. The application of finite element methods to distributed systems is described, using both separate discretizations in space and time, and a combined space-time discretization. The inclusion of both viscous and hysteretic damping is shown to add little to the difficulty of the solution. Temporal finite elements are also seen to be of considerable interest when applied to non-linear systems, both when the system parameters are time-dependent and also when they are functions of displacement. Solutions are given for many different examples, and the computer programs used for the finite element methods are included in an Appendix.
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Proteolysis-inducing factor (PIF), a tumour-produced cachectic factor, induced a dose-dependent decrease in protein synthesis in murine myotubes, together with an increase in phosphorylation of eucaryotic initiation factor 2 (eIF2) on the alpha-subunit. Both insulin (1 nM) and insulin-like growth factor I (IGF-I) (13.2 nM) attenuated the depression of protein synthesis by PIF and the increased phosphorylation of eIF2alpha, by inhibiting the activation (autophosphorylation) of the dsRNA-dependent protein kinase (PKR) by induction of protein phosphatase 1. A low-molecular weight inhibitor of PKR also reversed the depression of protein synthesis by PIF to the same extent, as did insulin and IGF-I. Both insulin and IGF-I-stimulated protein synthesis in the presence of PIF, and this was attenuated by Salubrinal, an inhibitor of phospho eIF2alpha phosphatase, suggesting that at least part of this action was due to their ability to inhibit phosphorylation of eIF2alpha. Both insulin and IGF-I also attenuated the induction of protein degradation in myotubes induced by PIF, this effect was also attenuated by Salubrinal. These results suggest an alternative mechanism involving PKR to explain the effect of insulin and IGF-I on protein synthesis and degradation in skeletal muscle in the presence of catabolic factors.
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Genomics, proteomics and metabolomics are three areas that are routinely applied throughout the drug-development process as well as after a product enters the market. This review discusses all three 'omics, reporting on the key applications, techniques, recent advances and expectations of each. Genomics, mainly through the use of novel and next-generation sequencing techniques, has advanced areas of drug discovery and development through the comparative assessment of normal and diseased-state tissues, transcription and/or expression profiling, side-effect profiling, pharmacogenomics and the identification of biomarkers. Proteomics, through techniques including isotope coded affinity tags, stable isotopic labeling by amino acids in cell culture, isobaric tags for relative and absolute quantification, multidirectional protein identification technology, activity-based probes, protein/peptide arrays, phage displays and two-hybrid systems is utilized in multiple areas through the drug development pipeline including target and lead identification, compound optimization, throughout the clinical trials process and after market analysis. Metabolomics, although the most recent and least developed of the three 'omics considered in this review, provides a significant contribution to drug development through systems biology approaches. Already implemented to some degree in the drug-discovery industry and used in applications spanning target identification through to toxicological analysis, metabolic network understanding is essential in generating future discoveries.
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Treatment of C2C12 myotubes with a tumour-derived proteolysis-inducing factor (PIF) at concentrations between 1 and 10 nM was shown to stimulate the activity of the apoptotic initiator caspases-8 and -9 and the apoptotic effector caspases-2,-3 and -6. This increased caspase activity was attenuated in myotubes pretreated with 50 μM eicosapentaenoic acid (EPA). At least part of the increase in caspase activity may be related to the increased proteasome proteolytic activity, since a caspase-3 inhibitor completely attenuated the PIF-induced increase in 'chymotrypsin-like' enzyme activity, the predominant proteolytic activity of the proteasome. However, Western blot analysis showed that PIF induced an increase in expression of the active form of caspase-3, which was also attenuated by EPA. Further Western blot analysis showed PIF increased the cytosolic content of cytochrome c, as well as expression of the pro-apoptotic protein bax but not the antiapoptotic protein bcl-2, which were both attenuated by 50 μM EPA. Induction of apoptosis by PIF in murine myotubes was confirmed by an increase in free nucleasomes formation and increased DNA fragmentation evidenced by a nucleasomal ladder typical of apoptotic cells. This process was again inhibited by pre-incubation with EPA. These results suggest that in addition to activating the proteasome, PIF induces apoptosis in C2C12 myotubes, possibly through the common intermediate arachidonic acid. Both of these processes would contribute to the loss of skeletal muscle in cancer cachexia.
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In this study, the central technique of in vitro culture has been used to further investigate whether LH/FSH-expressing, but clinically "functionless" pituitary adenomas are gonadotropinomas or whether their hormone secretion is due to transdifferentiation events. 664 "functionless" pituitary adenomas were examined for hormone secretion by in vitro culture and for hormone content by immunostaining. The results were correlated with the clinical findings. 40% of the tumours (n = 263) secreted at least one of the gonadotropins alone, 8% (n = 53) exhibited various patterns of anterior pituitary hormones, whilst the remaining 52% of tumours were not associated with any hormone. In the secretory tumours, immunostaining revealed only a few scattered hormone-containing cells (5 to 15%). Mild hyperprolactinaemia was observed in some cases, presumably because of pressure effects of the tumours. The majority of the patients suffered clear cut hypopituitarism (p < 0.05). Pre-operatively, gonadotropin hypersecretion was observed in 3 cases, but only one of these secreted hormones in culture. Interestingly, a higher proportion of tumours removed from patients with hypopituitarism showed secretory activity in vitro than those tumours removed from patients showing no hormonal dysfunction or hyperprolactinaemia. We conclude that the term "gonadotropinoma" to describe functionless pituitary tumours associated with LH and/or FSH secretion is a misnomer, because the presence of LH and/or FSH confirmed by in vitro methods in the present series is a result of only a few scattered cells. We suggest that primary pituitary tumour cells differentiate into a secretory type (transdifferentiation), possibly in response to altered serum hormone levels such as decreased steroids. Further work is required to identify the factors which trigger the altered cells' characteristics. © J. A. Barth Verlag in Georg Thieme Verlag KG.
Resumo:
Genomics, proteomics and metabolomics are three areas that are routinely applied throughout the drug-development process as well as after a product enters the market. This review discusses all three 'omics, reporting on the key applications, techniques, recent advances and expectations of each. Genomics, mainly through the use of novel and next-generation sequencing techniques, has advanced areas of drug discovery and development through the comparative assessment of normal and diseased-state tissues, transcription and/or expression profiling, side-effect profiling, pharmacogenomics and the identification of biomarkers. Proteomics, through techniques including isotope coded affinity tags, stable isotopic labeling by amino acids in cell culture, isobaric tags for relative and absolute quantification, multidirectional protein identification technology, activity-based probes, protein/peptide arrays, phage displays and two-hybrid systems is utilized in multiple areas through the drug development pipeline including target and lead identification, compound optimization, throughout the clinical trials process and after market analysis. Metabolomics, although the most recent and least developed of the three 'omics considered in this review, provides a significant contribution to drug development through systems biology approaches. Already implemented to some degree in the drug-discovery industry and used in applications spanning target identification through to toxicological analysis, metabolic network understanding is essential in generating future discoveries.
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Mixed-content miscellanies (very frequent in the Byzantine and mediaeval Slavic written heritage) are usually defined as collections of works with non-occupational, non-liturgical application, and texts in them are selected and arranged according to no identifiable principle. It is a “readable” type of miscellanies which were compiled mainly on the basis of the cognitive interests of compilers and readers. Just like the occupational ones, they also appeared to satisfy public needs but were intended for individual usage. My textological comparison had shown that mixed- content miscellanies often showed evidence of a stable content – some of them include the same constituent works in the same order, regardless that the manuscripts had no obvious genetic relationship. These correspondences were sufficiently numerous and distinctive that they could not be merely fortuitous, and the only sensible interpretation was that even when the operative organizational principle was not based on independently identifiable criteria, such as the church calendar, liturgical function, or thematic considerations, mixed-content miscellanies (or, at least, portions of their contents) nonetheless fell into types. In this respect, the apparent free selection and arrangement of texts in mixed-content miscellanies turns out to be illusory. The problem was – as the corpus of manuscripts that I and my colleagues needed to examine grew – our ability to keep track of the structure of each one, and to identify structural correspondences among manuscripts within the corpus, diminished. So, at the end of 1993 I addressed a letter to Prof. David Birnbaum (University of Pittsburgh, PA) with a request to help me to solve the problem. He and my colleague Andrey Boyadzhiev (Sofia University) pointed out to me that computers are well suited to recording, processing, and analyzing large amounts of data, and to identifying patterns within the data, and their proposal was that we try to develop a computer system for description of manuscripts, for their analysis and of course, for searching the data. Our collaboration in this project is now ten years old, and our talk today presents an overview of that collaboration.
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Since the first discovery of S100 members in 1965, their expressions have been affiliated with numerous biological functions in all cells of the body. However, in the recent years, S100A4, a member of this superfamily has emerged as the central target in generating new avenue for cancer therapy as its overexpression has been correlated with cancer patients’ mortality as well as established roles as motility and metastasis promoter. As it has no catalytic activity, S100A4 has to interact with its target proteins to regulate such effects. Up to date, more than 10 S100A4 target proteins have been identified but the mechanical process regulated by S100A4 to induce motility remains vague. In this work, we demonstrated that S100A4 overexpression resulted in actin filaments disorganisation, reduction in focal adhesions, instability of filopodia as well as exhibiting polarised morphology. However, such effects were not observed in truncated versions of S100A4 possibly highlighting the importance of C terminus of S100A4 target recognition. In order to assess some of the intracellular mechanisms that may be involved in promoting migrations, different strategies were used, including active pharmaceutical agents, inhibitors and knockdown experiments. Treatment of S100A4 overexpressing cells with blebbistatin and Y-27632, non muscle myosin IIA (NMMIIA) inhibitors, as well as knockdown of NMMIIA, resulted in motility enhancement and focal adhesions reduction proposing that NMMIIA assisted S100A4 in regulating cell motility but its presence is not essential. Further work done using Cos 7 cell lines, naturally lacking NMMIIA, further demonstrated that S100A4 is capable of regulating cell motility independent of NMMIIA, possibly through poor maturation of focal adhesion. Given that all these experiments highlighted the independency of NMMIIA towards migration, a protein that has been put at the forefront of S100A4-induced motility, we aimed to gather further understanding regarding the other molecular mechanisms that may be at play for motility. Using high throughput imaging (HCI), 3 compounds were identified to be capable of inhibiting S100A4-mediated migration. Although we have yet to investigate the underlying mechanism for their effects, these compounds have been shown to target membrane proteins and the externalisation of S100 proteins, for at least one of the compounds, leading us to speculate that preventing externalisation of S100A4 could potentially regulate cell motility.
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During the 2004 growing season, five raspberry cultivars were evaluated in terms of their susceptibility to the raspberry cane midge (Resseliella theobaldi Barnes). The trial was carried out at Berkenye, Nógrád County, Hungary. The cultivars evaluated were ‘Rubaca’ from Germany, ‘Fertődi Zamatos’ from Hungary, ‘Tulameen’ from Canada, and ‘Autumn Bliss’ and ‘Golden Bliss’ from the United Kingdom. Every other week, twenty-five split primocanes of each cultivar were randomly collected for laboratory examination. Data recorded for each cultivar included the mean number of larvae, the mean split length, and the mean extent of bark peeling per primocane. Pearson’s linear correlation coefficients were calculated for the correlations between the annual mean number of larvae per primocane on the one hand, and the annual cumulative mean split length per primocane and annual mean extent of bark peeling per primocane on the other hand. There was a weak correlation between annual mean number of larvae and annual cumulative mean split length, and a stronger correlation between annual mean number of larvae and annual mean extent of bark peeling. Annual mean number of larvae per primocane and annual mean extent of bark peeling per primocane were both highest in ‘Rubaca’, which means that the number of larvae per cane largely depends on the extent of stem peeling, although longitudinal splitting may also play a role. Therefore, cultivars with hardly any bark peeling and few and small longitudinal splits can be presumed to be less susceptible to infestation by the raspberry cane midge. Using these criteria, the least susceptible of the five cultivars evaluated would be ‘Tulameen’ and ‘Fertődi Zamatos’. Further research is needed to confirm this conclusion and to gather data on other factors which affect cultivar choice for new plantations, including winter hardiness, and susceptibility to cane diseases.
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The purpose of the research study was to determine the role occupational therapy plays in the management of sickle cell disease (SCD). A descriptive survey was administered to 39 persons living with or caring for persons living with SCD. This survey was administered at two sickle cell foundations and one hospital. ^ The research study determined that none of the 10.3% of the sample who had rehabilitative therapy received occupational therapy. Furthermore, at least 50% of persons surveyed agreed that SCD affected their activities of daily living; at least 38.5% agreed that work and productive activities were hampered; and at least 18% agreed that play/leisure activities were affected. No one within the sample received gene therapy. ^ It was concluded that occupational therapy is relevant for persons who are disabled by SCD. It is recommended that occupational therapists realize the importance of treating patients with SCD from a more holistic perspective. ^