Duchenne dystrophy

Wood, Donald S.; Sorenson, Martha M.; Eastwood, Abraham B.; Charash, William E.; Reuben, John P.

doi:10.1212/wnl.28.5.447

Cited by 57 publications

(18 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The similarity of Po?cm -2 observed in healthy subjects and patients with COPD does not support the hypothesis that a myopathic process exists in the latter group, since the decrease in strength in this condition would be disproportionately greater than loss in muscle CSA, indicating an impairment of the contractile apparatus [21,22]. At first sight, this result may appear surprising given the common belief that type II fibres, whose proportion is increased in COPD, are stronger than type I fibres.…”

Section: Discussionmentioning

confidence: 91%

In vitroandin vivocontractile properties of the vastus lateralis muscle in males with COPD

Debigaré

Ch²,

Fs³

et al. 2003

Eur Respir J

View full text Add to dashboard Cite

Peripheral muscle weakness is common in chronic obstructive pulmonary disease (COPD) but it is still under debate whether weakness is due to atrophy or contractile dysfunction.In vitro and in vivo contractile properties of the vastus lateralis muscle were studied in 16 patients with stable COPD (forced expiratory volume in one second 39 ¡ 16% of predicted, age 67 ¡ 4 yrs (mean ¡ SD)) and nine sedentary control subjects. Isometric knee extensor strength was measured while mid-thigh muscle cross-sectional area (MTMCSA) was obtained using computed tomography. Muscle strips from the vastus lateralis obtained through open biopsy were rapidly suspended in an oxygenated KrebsRinger solution that was maintained at 35uC with a pH of 7.40 to study their contractile properties.The isometric knee extensors strength/MTMCSA ratio was 0.50¡0.08 versus 0.58¡0.06 kg?cm -2 for COPD and control subjects, respectively. The muscle bundle cross-sectional area (CSA) was 4.6¡2.1 and 4.4¡3.1 mm -2 , the length at which active tension was maximum was 15¡4 and 15¡3 mm, and maximal isometric peak forces normalised for CSA were 4.3¡2.7 and 4.8¡2.6 N?cm -2 for COPD and control subjects, respectively. The force/frequency relationship tended to be shifted to the right in patients with COPD, meaning that a higher stimulation frequency was necessary to produce the same relative force. Patients with COPD had a lower proportion of type I fibre than controls (26¡12% versus 39¡11%) with reciprocal significant increase in type IIb fibre proportion (20 ¡ 16% versus 8 ¡ 4%). The proportion of type IIa fibres was similar between the two groups.These results suggest that the contractile properties of the vastus lateralis are preserved in patients with chronic obstructive pulmonary disease. Therefore, the reduction in the quadriceps strength in patients with chronic obstructive pulmonary disease cannot be explained on the basis of an alteration of the contractile apparatus.

show abstract

Section: Discussionmentioning

confidence: 91%

In vitroandin vivocontractile properties of the vastus lateralis muscle in males with COPD

Debigaré

Ch²,

Fs³

et al. 2003

Eur Respir J

View full text Add to dashboard Cite

show abstract

“…In an earlier study, Wood, Sorenson, Eastwood, Charash & Reuben (1978) have shown that 64 % of the DMD fibres developed less tension than the lowest tension (ca 10 N/cm2) measured in normal human fibres. However, these authors could not expand on this observation because the fibre types could not be identified.…”

Section: Normalfibresmentioning

confidence: 86%

Physiological properties of skinned fibres from normal and dystrophic (Duchenne) human muscle activated by Ca2+ and Sr2+.

Fink

Stephenson

Williams

1990

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. Contractile activation properties of various types of normal and dystrophic (Duchenne muscular dystrophy, DMD) human muscle fibres were investigated using mechanically skinned fibres activated in Ca2+-and Sr2+-buffered solutions at room temperature (21-25°C).2. The majority of the normal human muscle fibres (18/22; 82 %) could be classified according to the Ca2+-and Sr2+-activation characteristics in the same three major groups as other mammalian skeletal muscle fibres studied previously: slowtwitch (8/22; 36%), fast-twitch (3/22; 14%) and fast-twitch intermediate (7/22; 32%), which correspond to the three major histological fibre types I, IIB and IIA respectively.3. Of these three major groups only the slow-twitch (type I; 14/24; 58 %) and the fast-twitch intermediate (type II A; 3/24; 13%) fibres were found in the DMD muscle, indicating that fast-twitch fibres of type II B were in very low proportion in DMD muscle.4. The DMD muscle contained a new group of fibres (4/24; 17 %) with different Ca2+-and Sr2+-activation characteristics from the three major histological types.This group of fibres is likely to be of embryonic type. 5. The maximum tension development ability of DMD fibres was less than 20% of that in normal fibres with the exception of some slow-twitch fibres which could produce near normal tension.6. A significant proportion of normal (4/22; 18%) and DMD (3/24; 13%) fibres were found to have a mixture of Ca2+-and Sr2+-activation characteristics. This can be explained by co-existence of various myofibrillar protein isoforms in different proportions with regulatory functions in the same individual fibre.7. The results demonstrate that DMD leads to marked diminution in the ability of most individual skeletal muscle fibres to develop tension, and causes changes in the overall fibre-type distribution in afflicted muscles.

show abstract

“…Importantly, the sarcomeric proteins at the M- and Z-band remain in the skinned fiber in contrast to other reconstituted methods. These experiments measure the Ca 2+ buffering capacities of the myofilament while measuring the development of tension or maximal force [58, 59]. Several groups have also reported differences in the level of basal force (at low Ca 2+ concentrations) after the incorporation of mutant cTnT or cTnI [38, 41].…”

Section: Reconstituted and Structural Assaysmentioning

confidence: 99%

Cardiac Troponin Mutations and Restrictive Cardiomyopathy

Parvatiyar

Pinto

Dweck

et al. 2010

Journal of Biomedicine and Biotechnology

View full text Add to dashboard Cite

Mutations in sarcomeric proteins have recently been established as heritable causes of Restrictive Cardiomyopathy (RCM). RCM is clinically characterized as a defect in cardiac diastolic function, such as, impaired ventricular relaxation, reduced diastolic volume and increased end-diastolic pressure. To date, mutations have been identified in the cardiac genes for desmin, α-actin, troponin I and troponin T. Functional studies in skinned muscle fibers reconstituted with troponin mutants have established phenotypes consistent with the clinical findings which include an increase in myofilament Ca2+ sensitivity and basal force. Moreover, when RCM mutants are incorporated into reconstituted myofilaments, the ability to inhibit the ATPase activity is reduced. A majority of the mutations cluster in specific regions of cardiac troponin and appear to be mutational “hot spots”. This paper highlights the functional and clinical characteristics of RCM linked mutations within the troponin complex.

show abstract

Duchenne dystrophy

Cited by 57 publications

References 0 publications

In vitroandin vivocontractile properties of the vastus lateralis muscle in males with COPD

In vitroandin vivocontractile properties of the vastus lateralis muscle in males with COPD

Physiological properties of skinned fibres from normal and dystrophic (Duchenne) human muscle activated by Ca2+ and Sr2+.

Cardiac Troponin Mutations and Restrictive Cardiomyopathy

Contact Info

Product

Resources

About