Search

Your search keyword '"Salmons, S."' showing total 207 results
Start Over Author "Salmons, S." Language english
207 results on '"Salmons, S."'

2. Atrophy, but not necrosis, in rabbit skeletal muscle denervated for periods up to one year

Author

Ashley, Z., Sutherland, H., Lanmuller, H., Russold, M.F., Unger, E., Bijak, M., Mayr, W., Boncompagni, S., Protasi, F., Salmons, S., and Jarvis, J.C.

Subjects
Electron microscopy -- Usage, Atrophy, Muscular -- Research, Histochemistry -- Research, Biological sciences
Abstract

Our understanding of the effects of long-term denervation on skeletal muscle is heavily influenced by an extensive literature based on the rat. We have studied physiological and morphological changes in an alternative model, the rabbit. In adult rabbits, tibialis anterior muscles were denervated unilaterally by selective section of motor branches of the common peroneal nerve and examined after 10, 36, or 51 wk. Denervation reduced muscle mass and cross-sectional area by 50-60% and tetanic force by 75%, with no apparent reduction in specific force (force per cross-sectional area of muscle fibers). The loss of mass was associated with atrophy of fast fibers and an increase in fibrous and adipose connective tissue; the diameter of slow fibers was preserved. Within fibers, electron microscopy revealed signs of ultrastructural disorganization of sarcomeres and tubular systems. This, rather than the observed transformation of fiber type from IIx to IIa, was probably responsible for the slow contractile speed of the muscles. The muscle groups denervated for 10, 36, or 51 wk showed no significant differences. At no stage was there any evidence of necrosis or regeneration, and the total number of fibers remained constant. These changes are in marked contrast to the necrotic degeneration and progressive decline in mass and force that have previously been found in long-term denervated rat muscles. The rabbit may be a better choice for a model of the effects of denervation in humans, at least up to 1 yr after lesion. force; shortening velocity; electron microscopy; histochemistry

Published
2007

12. Critical properties of $\Phi^4_{1+1}$-theory in Light-Cone Quantization

Author

Grange, Pierre, Salmons, S., Werner, Ernst, Laboratoire de Physique Mathématique et Théorique (PMT), Centre National de la Recherche Scientifique (CNRS)-Université Montpellier 2 - Sciences et Techniques (UM2), Institut fur Theoretische Physik, D-93040, Universitat Regensburg - Germany, and Universität Regensburg (UR)

Subjects
High Energy Physics - Theory, [PHYS.HTHE]Physics [physics]/High Energy Physics - Theory [hep-th], [PHYS.MPHY]Physics [physics]/Mathematical Physics [math-ph], PACS: 11.10.Ef, 11.10.St, 11.30.Rd
Abstract

The dynamics of the phase transition of the continuum $\Phi ^{4}_{1+1}$-theory in Light Cone Quantization is reexamined taking into account fluctuations of the order parameter $< \Phi >$ in the form of dynamical zero mode operators (DZMO) which appear in a natural way via the Haag expansion of the field $\Phi (x)$ of the interacting theory. The inclusion of the DZM-sector changes significantly the value of the critical coupling, bringing it in agreement within 2% with the most recent Monte-Carlo and high temperature/strong coupling estimates. The critical slowing down of the DZMO governs the low momentum behavior of the dispersion relation through invariance of this DZMO under conformal transformations preserving the local light cone structure. The critical exponent $\eta$ characterising the scaling behaviour at $k^2 \to 0$ comes out in agreement with the known value 0.25 of the Ising universality class. $\eta$ is made of two contributions: one, analytic $(75 %$) and another (25%) which can be evaluated only numerically with an estimated error of 3%. The $\beta$-function is then found from the non-perturbative expression of the physical mass. It is non-analytic in the coupling constant with a critical exponent $\omega=2$. However, at D=2, $\omega$ is not parametrisation independent with respect to the space of coupling constants due to this strong non-analytic behaviour., Comment: Latex, 22 pages, 8 Postscript figures,Appendix

Published
2002
Full Text
View/download PDF

14. The authors reply

Author

Lexell, J., Jarvis, J. C., Currie, J., Downham, D. Y., and Salmons, S.

Subjects
Correspondence
Published
1995

27. Serum 1,25-dihydroxyvitamin D concentrations in premature infants: preliminary results.

Author

Hillman, Laura, Salmons, Sharon, Dokoh, Shigeharu, Hillman, L S, Salmons, S, and Dokoh, S

Subjects
AGE distribution, BREAST milk, CALCIUM, COMPARATIVE studies, PREMATURE infants, RESEARCH methodology, MEDICAL cooperation, PARATHYROID hormone, PHOSPHORUS, RESEARCH, RESEARCH funding, EVALUATION research, CALCITRIOL
Abstract

Serum 1,25(OH)2D concentrations were measured in serial serum samples from 19 premature infants of 29.6 +/- 1.3 weeks gestation and 1,129 +/- 159 g birthweight. 1,25(OH)2D was always normal or elevated and mean concentrations increased with age (adult, 55.2 +/- 13; infants, 1-2 weeks, 81.5 +/- 37.7 pg/mg; 3 weeks, 65 +/- 21; 6 weeks, 90.0 +/- 17.3; 9 weeks, 99.0 +/- 25.1; 12 weeks, 103.3 +/- 26.6 pg/ml). No correlation was seen with 25-OHD. Infants given 800 IU D2 supplements had lower 1,25(OH)2D levels than infants given 400 IU D2. Breast fed infants had initially higher 1,25(OH)2D levels; however, this was not sustained. These preliminary data suggest that premature infants regulate 1,25(OH)2D production similar to more mature infants and children. Whether the premature infant has a normal gastrointestinal and/or bone responsiveness to 1,25(OH)2D and whether these elevated 1,25(OH)2D concentrations are "adequately elevated" requires further study. [ABSTRACT FROM AUTHOR]

Published
1985
Full Text
View/download PDF

30. Ultrastructural aspects of the transformation of muscle fibre type by long term stimulation: changes in Z discs and mitochondria

Author

Salmons, S, Gale, D R, and Sréter, F A

Subjects
Adenosine Triphosphatases, Male, Microscopy, Electron, Myofibrils, Muscles, Animals, Female, Rabbits, Electric Stimulation, Research Article, Mitochondria, Muscle, Muscle Contraction
Abstract

The criteria which serve to distinguish the slow from the fast type of mammalian skeletal muscle include differences at the ultrastructural level, in particular differences in Z disc morphology and mitochondrial content. If a fast muscle is subjected to sustained low frequency impulse activity similar to that normally received by a slow muscle, its physiological and biochemical properties become indistinguishable from those of a slow muscle. In the present study we have examined the fine structure of fast muscles stimulated in this way. The thickness of Z discs was significantly greater than that of control fast muscles and indistinguishable from that of slow muscles. Mitochondrial profiles, seen only infrequently in control fast muscles, were abundant in their stimulated counterparts. The regulatory influence of impulse activity on the differentiation of skeletal muscle thus extends to some of its most characteristic ultrastructural features.

Published
1978

Catalog

Books, media, physical & digital resources
See catalog results