MRI biomarker assessment of neuromuscular disease progression: a prospective observational cohort study

BACKGROUND: A substantial impediment to progress in trials of new therapies in neuromuscular disorders is the absence of responsive outcome measures that correlate with patient functional deficits and are sensitive to early disease processes. Irrespective of the primary molecular defect, neuromuscular disorder pathological processes include disturbance of intramuscular water distribution followed by intramuscular fat accumulation, both quantifiable by MRI. In pathologically distinct neuromuscular disorders, we aimed to determine the comparative responsiveness of MRI outcome measures over 1 year, the validity of MRI outcome measures by cross-sectional correlation against functionally relevant clinical measures, and the sensitivity of specific MRI indices to early muscle water changes before intramuscular fat accumulation beyond the healthy control range. METHODS: We did a prospective observational cohort study of patients with either Charcot-Marie-Tooth disease 1A or inclusion body myositis who were attending the inherited neuropathy or muscle clinics at the Medical Research Council (MRC) Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, London, UK. Genetic confirmation of the chromosome 17p11·2 duplication was required for Charcot-Marie-Tooth disease 1A, and classification as pathologically or clinically definite by MRC criteria was required for inclusion body myositis. Exclusion criteria were concomitant diseases and safety-related MRI contraindications. Healthy age-matched and sex-matched controls were also recruited. Assessments were done at baseline and 1 year. The MRI outcomes-fat fraction, transverse relaxation time (T2), and magnetisation transfer ratio (MTR)-were analysed during the 12-month follow-up, by measuring correlation with functionally relevant clinical measures, and for T2 and MTR, sensitivity in muscles with fat fraction less than the 95th percentile of the control group. FINDINGS: Between Jan 19, 2010, and July 7, 2011, we recruited 20 patients with Charcot-Marie-Tooth disease 1A, 20 patients with inclusion body myositis, and 29 healthy controls (allocated to one or both of the 20-participant matched-control subgroups). Whole muscle fat fraction increased significantly during the 12-month follow-up at calf level (mean absolute change 1·2%, 95% CI 0·5-1·9, p=0·002) but not thigh level (0·2%, -0·2 to 0·6, p=0·38) in patients with Charcot-Marie-Tooth disease 1A, and at calf level (2·6%, 1·3-4·0, p=0·002) and thigh level (3·3%, 1·8-4·9, p=0·0007) in patients with inclusion body myositis. Fat fraction correlated with the lower limb components of the inclusion body myositis functional rating score (ρ=-0·64, p=0·002) and the Charcot-Marie-Tooth examination score (ρ=0·63, p=0·003). Longitudinal T2 and MTR changed consistently with fat fraction but more variably. In muscles with a fat fraction lower than the control group 95th percentile, T2 was increased in patients compared with controls (regression coefficients: inclusion body myositis thigh 4·0 ms [SE 0·5], calf 3·5 ms [0·6]; Charcot-Marie-Tooth 1A thigh 1·0 ms [0·3], calf 2·0 ms [0·3]) and MTR reduced compared with controls (inclusion body myositis thigh -1·5 percentage units [pu; 0·2], calf -1·1 pu [0·2]; Charcot-Marie-Tooth 1A thigh -0·3 pu [0·1], calf -0·7 pu [0·1]). INTERPRETATION: MRI outcome measures can monitor intramuscular fat accumulation with high responsiveness, show validity by correlation with conventional functional measures, and detect muscle water changes preceding marked intramuscular fat accumulation. Confirmation of our results in further cohorts with these and other muscle-wasting disorders would suggest that MRI biomarkers might prove valuable in experimental trials. FUNDING: Medical Research Council UK

Critical evaluation of proteomic protocols for passion fruit (Passiflora edulis Sims) leaves, a crop with juice market benefits

Passion fruit grows practically all over Brazilian territory; its production is largely destined to juice industry and expanding to overseas markets. The suitability of four protein extraction protocols for plant proteome was  investigated to determine the best choice for studies concerning passion fruit leaf proteins. Trichloroacetic acid (TCA)/acetone extraction; isoelectric  focusing (IEF) buffer extraction; phenol (Phe) extraction and Phe-SDS extraction were tested. The Phe method produced the best results, showing higher reproducibility of resolved protein spots and clearer 2D gel  background staining. In comparison, the Phe-SDS method presented fewer spots and lower reproducibility. The TCA/acetone method produced the fewest identifiable spots and the IEF buffer produced the poorest results,displaying fewer reproducibly detected spots, more vertical streaks and darker 2D staining. Selected spots, obtained with Phe method, were identified by spectrometric analysis (MALDI-TOF-TOF) to exemplify the viability to perform more comprehensive proteomic studies with passion fruit leaves and, therefore increase information about stress-related and developmental responses in this fruit crop.Key words: Passion fruit, proteomic, protein extraction, juice industry

Melting of polymer blends in single-screw extrusion : an experimental study

Melting is a major step in plasticating single screw extrusion, but most of the existing phenomenological know how was gathered by performing Maddock-type experiments with homopolymers. Given the current widespread industrial use of polymer blends, it is worth determining whether the same mechanisms and mathematical models apply, or whether different sequences develop. This work reports the results of Maddock-type experiments using a PA6/PP blend, both in its immiscible and compatibilized varieties. A melting mechanism combining the features of the classical Tadmor mechanism and of the dispersed melting mechanism, also previously reported in the literature, was observed.The authors are grateful to Portuguese Fundacao para a Ciencia e Tecnologia for supporting this work under grant SFRH/BD/19997/2004 and to DSM, the Netherlands, for supplying PA6

The D allele of angiotensin-converting enzyme gene is associated with greater hemodynamic response to resistance exercises

HYPOTHESIS/INTRODUCTION: The association of ACE I/D polymorphism and hemodynamic response to exercise have been limited to primarily aerobic exercises. We hypothesized that D allele carriers would show greater hemodynamic response to resistance exercise, as has been observed with aerobic. This study aimed to investigate the association of ACE I/D polymorphism and hemodynamic (blood pressure (BP), heart rate (HR) and rate-pressure product (RPP)) response to resistance exercise in young healthy subjects.MATERIALS AND METHODS: ACE I/D polymorphisms were studied by PCR analysis from 75 healthy men. Subjects completed a resistance exercise session of three sets of 10 knee extension repetitions with loads of 50, 75 and 100% of 10RM and two-minute rest intervals. Hemodynamic measures were recorded before and immediately after each set. Analysis of variance was used to identify significant differences among ACE genotypes. RESULTS: ACE I/D polymorphism is associated with hemodynamic response to resistance exercise, as healthy subjects with ACE D allele were prone to higher responses. In addition, this phenotypic difference seems to be a load-dependent trend. CONCLUSION: ACE DD carriers exhibit greater heart work during resistance exercise. Future studies should focus on the influence of resistance training period with different workloads on the hemodynamic response in healthy individuals with different ACE genotypes

In vitro production of bovine embryos derived from individual donors in the Corral® dish

Background: Since the identity of the embryo is of outmost importance during commercial in vitro embryo production, bovine oocytes and embryos have to be cultured strictly per donor. Due to the rather low yield of oocytes collected after ovum pick-up (OPU) per individual cow, oocyte maturation and embryo culture take place in small groups, which is often associated with inferior embryo development. The objective of this study was to improve embryonic development in small donor groups by using the Corral (R) dish. This commercial dish is designed for human embryo production. It contains two central wells that are divided into quadrants by a semi-permeable wall. In human embryo culture, one embryo is placed per quadrant, allowing individual follow-up while embryos are exposed to a common medium. In our study, small groups of oocytes and subsequently embryos of different bovine donors were placed in the Corral (R) dish, each donor group in a separate quadrant. Results: In two experiments, the Corral (R) dish was evaluated during in vitro maturation (IVM) and/or in vitro culture (IVC) by grouping oocytes and embryos of individual bovine donors per quadrant. At day 7, a significantly higher blastocyst rate was noted in the Corral (R) dish used during IVM and IVC than when only used during IVM (12.9% +/- 2.10 versus 22.8% +/- 2.67) (P < 0.05). However, no significant differences in blastocyst yield were observed anymore between treatment groups at day 8 post insemination. Conclusions: In the present study, the Corral (R) dish was used for in vitro embryo production (IVP) in cattle; allowing to allocate oocytes and/or embryos per donor. As fresh embryo transfers on day 7 have higher pregnancy outcomes, the Corral (R) dish offers an added value for commercial OPU/IVP, since a higher blastocyst development at day 7 is obtained when the Corral (R) dish is used during IVM and IVC

Recent developments of the Hierarchical Reference Theory of Fluids and its relation to the Renormalization Group

The Hierarchical Reference Theory (HRT) of fluids is a general framework for the description of phase transitions in microscopic models of classical and quantum statistical physics. The foundations of HRT are briefly reviewed in a self-consistent formulation which includes both the original sharp cut-off procedure and the smooth cut-off implementation, which has been recently investigated. The critical properties of HRT are summarized, together with the behavior of the theory at first order phase transitions. However, the emphasis of this presentation is on the close relationship between HRT and non perturbative renormalization group methods, as well as on recent generalizations of HRT to microscopic models of interest in soft matter and quantum many body physics.Comment: 17 pages, 5 figures. Review paper to appear in Molecular Physic