271 research outputs found

    Natural history of limb girdle muscular dystrophy R9 over 6 years: searching for trial endpoints

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    OBJECTIVE: Limb girdle muscular dystrophy type R9 (LGMD R9) is an autosomal recessive muscle disease for which there is currently no causative treatment. The development of putative therapies requires sensitive outcome measures for clinical trials in this slowly progressing condition. This study extends functional assessments and MRI muscle fat fraction measurements in an LGMD R9 cohort across 6 years. METHODS: Twenty‐three participants with LGMD R9, previously assessed over a 1‐year period, were re‐enrolled at 6 years. Standardized functional assessments were performed including: myometry, timed tests, and spirometry testing. Quantitative MRI was used to measure fat fraction in lower limb skeletal muscle groups. RESULTS: At 6 years, all 14 muscle groups assessed demonstrated significant increases in fat fraction, compared to eight groups in the 1‐year follow‐up study. In direct contrast to the 1‐year follow‐up, the 6‐min walk test, 10‐m walk or run, timed up and go, stair ascend, stair descend and chair rise demonstrated significant decline. Among the functional tests, only FVC significantly declined over both the 1‐ and 6‐year studies. INTERPRETATION: These results further support fat fraction measurements as a primary outcome measure alongside functional assessments. The most appropriate individual muscles are the vastus lateralis, gracilis, sartorius, and gastrocnemii. Using composite groups of lower leg muscles, thigh muscles, or triceps surae, yielded high standardized response means (SRMs). Over 6 years, quantitative fat fraction assessment demonstrated higher SRM values than seen in functional tests suggesting greater responsiveness to disease progression

    Natural history of limb girdle muscular dystrophy R9 over 6 years: searching for trial endpoints

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    OBJECTIVE: Limb girdle muscular dystrophy type R9 (LGMD R9) is an autosomal recessive muscle disease for which there is currently no causative treatment. The development of putative therapies requires sensitive outcome measures for clinical trials in this slowly progressing condition. This study extends functional assessments and MRI muscle fat fraction measurements in an LGMD R9 cohort across 6 years. METHODS: Twenty‐three participants with LGMD R9, previously assessed over a 1‐year period, were re‐enrolled at 6 years. Standardized functional assessments were performed including: myometry, timed tests, and spirometry testing. Quantitative MRI was used to measure fat fraction in lower limb skeletal muscle groups. RESULTS: At 6 years, all 14 muscle groups assessed demonstrated significant increases in fat fraction, compared to eight groups in the 1‐year follow‐up study. In direct contrast to the 1‐year follow‐up, the 6‐min walk test, 10‐m walk or run, timed up and go, stair ascend, stair descend and chair rise demonstrated significant decline. Among the functional tests, only FVC significantly declined over both the 1‐ and 6‐year studies. INTERPRETATION: These results further support fat fraction measurements as a primary outcome measure alongside functional assessments. The most appropriate individual muscles are the vastus lateralis, gracilis, sartorius, and gastrocnemii. Using composite groups of lower leg muscles, thigh muscles, or triceps surae, yielded high standardized response means (SRMs). Over 6 years, quantitative fat fraction assessment demonstrated higher SRM values than seen in functional tests suggesting greater responsiveness to disease progression

    Quantitative Muscle MRI as an Assessment Tool for Monitoring Disease Progression in LGMD2I: A Multicentre Longitudinal Study

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    Background Outcome measures for clinical trials in neuromuscular diseases are typically based on physical assessments which are dependent on patient effort, combine the effort of different muscle groups, and may not be sensitive to progression over short trial periods in slow-progressing diseases. We hypothesised that quantitative fat imaging by MRI (Dixon technique) could provide more discriminating quantitative, patient-independent measurements of the progress of muscle fat replacement within individual muscle groups. Objective To determine whether quantitative fat imaging could measure disease progression in a cohort of limb-girdle muscular dystrophy 2I (LGMD2I) patients over a 12 month period. Methods 32 adult patients (17 male;15 female) from 4 European tertiary referral centres with the homozygous c.826C>A mutation in the fukutin-related protein gene (FKRP) completed baseline and follow up measurements 12 months later. Quantitative fat imaging was performed and muscle fat fraction change was compared with (i) muscle strength and function assessed using standardized physical tests and (ii) standard T1-weighted MRI graded on a 6 point scale. Results There was a significant increase in muscle fat fraction in 9 of the 14 muscles analyzed using the quantitative MRI technique from baseline to 12 months follow up. Changes were not seen in the conventional longitudinal physical assessments or in qualitative scoring of the T1w images. Conclusions Quantitative muscle MRI, using the Dixon technique, could be used as an important longitudinal outcome measure to assess muscle pathology and monitor therapeutic efficacy in patients with LGMD2I

    Downregulation of the anaphase-promoting complex (APC)7 in invasive ductal carcinomas of the breast and its clinicopathologic relationships

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    INTRODUCTION: The anaphase-promoting complex (APC) is a multiprotein complex with E3 ubiquitin ligase activity, which is required for the ubiquitination of securin and cyclin-B. Moreover, the mitotic spindle checkpoint is activated if APC activation is prevented. In addition, several APC-targeting molecules such as securin, polo-like kinase, aurora kinase, and SnoN have been reported to be oncogenes. Therefore, dysregulation of APC may be associated with tumorigenesis. However, the clinical significance and the involvement of APC in tumorigenesis have not been investigated. METHODS: The expression of APC7 was immunohistochemically investigated in 108 invasive ductal carcinomas of the breast and its relationship with clinicopathologic parameters was examined. The expression of APC7 was defined as positive when the summed scores of staining intensities (0 to 3+) and stained proportions (0 to 3+) exceeded 3+. RESULTS: Positive APC7 expression was less frequent than its negative expression when histologic (P = 0.009) or nuclear grade (P = 0.009), or mitotic number (P = 0.0016) was elevated. The frequency of APC7 negative expression was higher in high Ki-67 or aneuploid groups than in low Ki-67 or diploid groups. CONCLUSION: These data show that loss of APC7 expression is more common in breast carcinoma cases with poor prognostic parameters or malignant characteristics. They therefore suggest that dysregulation of APC activity, possibly through downregulation of APC7, may be associated with tumorigenesis in breast cancer

    The Mitotic Arrest Deficient Protein MAD2B Interacts with the Small GTPase RAN throughout the Cell Cycle

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    Contains fulltext : 81260.pdf (publisher's version ) (Open Access)BACKGROUND: Previously, we identified the mitotic arrest deficient protein MAD2B (MAD2L2) as a bona fide interactor of the renal cell carcinoma (RCC)-associated protein PRCC. In addition, we found that fusion of PRCC with the transcription factor TFE3 in t(X;1)(p11;q21)-positive RCCs results in an impairment of this interaction and, concomitantly, an abrogation of cell cycle progression. Although MAD2B is thought to inhibit the anaphase promoting complex (APC) by binding to CDC20 and/or CDH1(FZR1), its exact role in cell cycle control still remains to be established. METHODOLOGY/PRINCIPAL FINDINGS: Using a yeast two-hybrid interaction trap we identified the small GTPase RAN, a well-known cell cycle regulator, as a novel MAD2B binding protein. Endogenous interaction was established in mammalian cells via co-localization and co-immunoprecipitation of the respective proteins. The interaction domain of RAN could be assigned to a C-terminal moiety of 60 amino acids, whereas MAD2B had to be present in its full-length conformation. The MAD2B-RAN interaction was found to persist throughout the cell cycle. During mitosis, co-localization at the spindle was observed. CONCLUSIONS/SIGNIFICANCE: The small GTPase RAN is a novel MAD2B binding protein. This novel protein-protein interaction may play a role in (i) the control over the spindle checkpoint during mitosis and (ii) the regulation of nucleocytoplasmic trafficking during interphase

    Why Do Situational Interviews Predict Performance? Is it Saying How You Would Behave or Knowing How You Should Behave?

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    Purpose: The present study examined two theoretical explanations for why situational interviews predict work-related performance, namely (a) that they are measures of interviewees’ behavioral intentions or (b) that they are measures of interviewees’ ability to correctly decipher situational demands. Design/Methodology/Approach: We tested these explanations with 101 students, who participated in a 2-day selection simulation. Findings: In line with the first explanation, there was considerable similarity between what participants said they would do and their actual behavior in corresponding work-related situations. However, the underlying postulated mechanism was not supported by the data. In line with the second explanation, participants’ ability to correctly decipher situational demands was related to performance in both the interview and work-related situations. Furthermore, the relationship between the interview and performance in the work-related situations was partially explained by this ability to decipher situational demands. Implications: Assessing interviewees’ ability to identify criteria might be of additional value for making selection decisions, particularly for jobs where it is essential to assess situational demands. Originality/Value: The present study made an effort to open the ‘black box’ of situational interview validity by examining two explanations for their validity. The results provided only moderate support for the first explanation. However, the second explanation was fully supported by these results

    Long-Branch Attraction Bias and Inconsistency in Bayesian Phylogenetics

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    Bayesian inference (BI) of phylogenetic relationships uses the same probabilistic models of evolution as its precursor maximum likelihood (ML), so BI has generally been assumed to share ML's desirable statistical properties, such as largely unbiased inference of topology given an accurate model and increasingly reliable inferences as the amount of data increases. Here we show that BI, unlike ML, is biased in favor of topologies that group long branches together, even when the true model and prior distributions of evolutionary parameters over a group of phylogenies are known. Using experimental simulation studies and numerical and mathematical analyses, we show that this bias becomes more severe as more data are analyzed, causing BI to infer an incorrect tree as the maximum a posteriori phylogeny with asymptotically high support as sequence length approaches infinity. BI's long branch attraction bias is relatively weak when the true model is simple but becomes pronounced when sequence sites evolve heterogeneously, even when this complexity is incorporated in the model. This bias—which is apparent under both controlled simulation conditions and in analyses of empirical sequence data—also makes BI less efficient and less robust to the use of an incorrect evolutionary model than ML. Surprisingly, BI's bias is caused by one of the method's stated advantages—that it incorporates uncertainty about branch lengths by integrating over a distribution of possible values instead of estimating them from the data, as ML does. Our findings suggest that trees inferred using BI should be interpreted with caution and that ML may be a more reliable framework for modern phylogenetic analysis

    University–industry collaboration: using meta-rules to overcome barriers to knowledge transfer

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    This is the final version of the article. Available from Springer Verlag via the DOI in this record.University–industry knowledge transfer is an important source wealth of creation for all partners; however, the practical management of this activity within universities is often hampered by procedural rigidity either through the absence of decision-making protocols to reconcile conflicting priorities or through the inconsistent implementation of existing policies. This is problematic, since it can impede operational effectiveness, prevent inter-organisational knowledge-creation and hamper organisational learning. This paper addresses this issue by adopting a cross-discipline approach and presenting meta-rules as a solution to aid organisational decision making. It is proposed that meta-rules can help resolve tensions arising from conflicting priorities between academics, knowledge transfer offices and industry and help facilitate strategic alignment of processes and policies within and between organisations. This research contributes to the growing debate on the strategic challenges of managing knowledge transfer and presents meta-rules as a practical solution to facilitate strategic alignment of internal and external stakeholder tensions. Meta-rules has previously only been applied in a computer intelligence context however, this research proves the efficacy of meta rules in a university–industry knowledge transfer context. This research also has practical implications for knowledge transfer office managers who can use meta-rules to help overcome resource limitations, conflicting priorities and goals of diverse internal and external stakeholders
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