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PubMed2006

Pectoral stretching program for women undergoing radiotherapy for breast cancer.

Surgery and radiotherapy commonly cause adverse musculoskeletal problems, particularly loss of strength and range of motion, in the upper quadrant of breast cancer patients. Few well-designed studies have investigated whether these impairments can be prevented. Stretching is an effective technique for increasing range of motion, hence the aim of this study was to investigate whether a stretching program reduced acute musculoskeletal impairments in patients undergoing radiotherapy for breast cancer. Sixty-four women were recruited prior to commencement of radiotherapy following breast cancer surgery. Participants were randomised to either a control or stretch group. Participants in both groups were reviewed by the physical therapist on a weekly basis for approximately 6 weeks, and were given general information about skin care and lymphedema. The control group received no advice about exercise. The stretch group received instruction on low-load, prolonged pectoral stretches, which were to be performed daily and were checked at weekly visits. Shoulder range of motion, strength, arm circumference, and quality of life measurements were taken prior to, and at completion of radiotherapy, and at 7 months after radiotherapy. There was no difference in any outcome between groups. Breast symptoms increased for both groups during radiotherapy, without loss of strength or range of movement. The incidence of lymphedema during the study was low for both groups and did not differ between groups. The pectoral stretching program did not influence the outcomes measured because the symptoms reported by patients were not a consequence of contracture.

Breast Neoplasms↗
PubMed1984

Salutary effect of fall in abdominal pressure during diaphragm paralysis.

To examine the mechanical effects of the fall in abdominal pressure (Pab) that occurs during inspiration in diaphragmatic paralysis, we studied lung inflation and rib cage expansion before and after the abdomen was opened in nine spontaneously breathing dogs with bilateral phrenicotomy . We measured Pab, tidal volume, and parasternal electromyographic (EMG) activity during quiet breathing and CO2-induced hyperpnea. In six dogs, we also measured changes in anteroposterior and transverse rib cage diameters, the resting length of the parasternal intercostal muscles, and the amount of shortening of these muscles during inspiration. Opening the abdomen caused a marked reduction in the fall in Pab during inspiration and invariably resulted in a decrease in tidal volume (mean decrease, 13%), which contrasted with marked increases in inspiratory rib cage expansion and in the amount of parasternal intercostal shortening. The procedure, however, did not affect the resting length or inspiratory EMG activity of the parasternals . These findings indicate that although the fall in Pab, which occurs during inspiration in diaphragmatic paralysis, causes paradoxical inward displacement of the ventral abdominal wall, it has a salutary effect on tidal volume. This phenomenon is probably due to the fact that the diaphragm is part of the abdominal wall.

Abdominal Muscles↗
PubMed1985

Decay of inspiratory muscle pressure during expiration in conscious humans.

In eight conscious spontaneously breathing adults we studied the decay of pressure developed by the inspiratory muscles during expiration (PmusI). PmusI was obtained according to the following equation: PmusI(t) = Ers X V(t) - Rrs X V(t), where V is volume and V is flow at any instant t during spontaneous expiration, and Ers and Rrs are, respectively, the passive elastance and resistance of the total respiratory system. Ers was determined with the relaxation method, and resistance with the interrupter method. All subjects showed marked braking of expiratory flow by PmusI. The mean time for PmusI to reduce to 50 and 0% amounted, respectively, to 23 and 79% of expiratory time. During expiration, 24-55% of the elastic energy stored during inspiration was used as resistive work and the remainder (45-76%) as negative work.

Adult↗
PubMed1980

Suxamethonium fasciculations: a topographical study.

It has been found in a group of 455 gynaecological patients that not all the voluntary muscles of the body respond to suxamethonium in the same way. One group of muscles (e.g. biceps) which is sensitive to suxamethonium, responds by fasciculating in almost every individual. A second, resistant, group of muscles (e.g. pectoralis major) is almost totally unresponsive to suxamethonium. A third muscle group (e.g. triceps) shows fasciculations in about 60% of cases and appears intimately associated with the development of suxamethonium pains, for if fasciculations do occur then suxamethonium pains are likely to ensure, but not necessarily involving all the fasciculating muscles. A theory to account for these different groups has been proposed involving the known variation in distribution of red and white muscle fibres throughout the body.

Adolescent↗
PubMed1996

The sternalis muscle: an unusual normal finding seen on mammography.

OBJECTIVE: We studied the appearance of the sternalis muscle on mammography and on CT and MR imaging. To our knowledge, this is the first description of this normal anatomic variant. An approach is provided that permits differentiation of the sternalis from significant pathology. SUBJECTS AND METHODS: Between January 1992 and December 1994, four women of an estimated 32,000 who had mammograms at the Massachusetts General Hospital had an unusual, irregular structure visible medially on the craniocaudal projection that posed a diagnostic dilemma. The records and imaging studies of these women and two others from the Deaconess Hospital breast imaging program were reviewed to determine the etiology of the findings seen by mammography and to establish a diagnostic approach. RESULTS: Surgery in one patient and cross-sectional imaging in the other five established that the structure was the sternalis muscle. Although it may be bilateral, the sternalis muscle was visible only unilaterally on the mammograms of these six women. The appearance of the muscle ranged from an irregularly rounded density at the sternal edge of the film to flame-shaped and almost completely surrounded by fat. CT and MR imaging are diagnostic when they show the longitudinal extent of the muscle, which lies anterior to the medial margin of the pectoralis major muscle. CONCLUSION: The sternalis muscle is an unusual variant of the chest wall musculature. It may be visible as a rounded or irregular density on the craniocaudal mammogram along the sternal edge of the film. With improved mammographic positioning it will be seen more frequently. The muscle has a variety of appearances that should be familiar to the radiologist to avoid confusion with a malignant lesion. The etiology can be confirmed and cancer excluded by CT or MR imaging.

Adult↗
PubMed1996

The avian low score normal muscle weakness alters decorin expression and collagen crosslinking.

Extracellular matrix development of chicken pectoral muscle was examined in the Low Score Normal (LSN) genetic muscle weakness and compared to both normal and avian muscular dystrophy (MD). At 20 days of embryonic development significant elevations were noted in LSN total glycosaminoglycan concentration and decorin, while at 14 days, LSN glycosaminoglycan and decorin levels were indistinguishable from the controls. Levels of a large skeletal muscle chondroitin sulfate proteoglycan (M-CSPG) appear to be unaffected. Morphologically, at 20 days, the extracellular matrix space between muscle fibers increased to a level characteristic to that observed in avian muscular dystrophy. At six weeks posthatch a marked increase in LSN collagen crosslinking relative to MD or control tissues was observed, while collagen concentration was not altered. By one year posthatch LSN collagen crosslink levels did not significantly differ from normal tissue. These data support the concept that the LSN muscle weakness is associated with changes in both proteoglycan and collagen characteristics.

Animals↗
PubMedDate not supplied

Muscle fiber types in the dystrophic puboischiofemoralis of commercial broilers.

Muscle fiber types, their diameters, lipid content, and nuclei distributions were studied in normal and necrotic puboischiofemoral muscles from commercial broiler chickens of the Hubbard strain. Three categories of puboischiofemoral fiber morphology (alpha R, beta R, and alpha W) occur in the cranial and caudal portions of the pars lateralis and in the cranial, medial, and caudal portions of the pars medialis. The greatest amount of necrosis occurred in the caudal portion of the pars medialis of the puboischiofemoralis. A fiber type characterized by a greatly enlarged and rounded or oval cross-section, decreased fat content, and internalized and clustered nuclei was present in necrotic muscle but not in normal muscle.

Animals↗
PubMed1986

Increased concentration of spectrin is observed in avian dystrophic muscle.

A significant increase in the concentration of spectrin has been observed in dystrophic chicken pectoralis major muscle when compared to normal fast-twitch muscle. In normal muscle, alpha-spectrin-specific immunofluorescence delineates each myofiber with a network pattern of staining at the sarcolemma with little staining within the cytoplasm. In dystrophic fibers, numerous intensely stained areas occur within the cytoplasm and staining at the sarcolemma is increased, thereby obscuring or eliminating the highly regular network arrangement of spectrin usually seen in this region. When immunofluorescence experiments are performed on microsomal vesicles isolated from normal and dystrophic tissues, only a small fraction of normal vesicles are stained, whereas most of the dystrophic vesicles are associated with spectrin. An increase in spectrin concentration is observed using immunoautoradiography of whole muscle and isolated microsomes, thus supporting the immunofluorescent observations described above. The early-age post-hatching when increases in spectrin concentration can be detected and the simplicity of the immunofluorescent technique make this observation useful as a new diagnostic parameter. This observation also shows that the distribution of spectrin and its concentration within nonerythroid cells can be modified by abnormal physiological states; this modification may contribute to subsequent symptoms, such as increased rigidity and abnormal calcium metabolism, that are observed in dystrophy.

Animals↗
PubMed2006

Electromyographic analysis in patients with multidirectional shoulder instability during pull, forward punch, elevation and overhead throw.

Multidirectional shoulder joint instability alters the role of dynamic stabilizers, as a result of which the motion patterns of the muscle around the shoulder joint are also changed. The aim of this study was to compare the muscle activity of patients with multidirectional shoulder instability and the control group during pull, forward punch, elevation and overhead throw. Fifteen subjects with multidirectional shoulder instability and fifteen control subjects with normal, healthy shoulders participated in the study. Both shoulders were tested in all subjects. Signals were recorded by surface EMG from eight different muscles during pull, forward punch, elevation and overhead throw. The mean and standard deviation of MVE% for the different movement types and time broadness values during overhead throw were determined for each muscle in both groups and compared with each other. Test results suggest that in case of patients with multidirectional shoulder instability the various motions are performed in a different way. The results give rise to the assumption that the centralization of the glenohumeral joint and the reduction of instability are attempted to be ensured by the organism through increasing the role of rotator cuff muscles and decreasing the role of the deltoid, biceps brachii and pectoralis maior muscles. The analysis of time broadness shows that in patients with multidirectional shoulder instability, the time difference between the peaks of normalized voluntary electrical activity is significantly greater than in the control group.

Adult↗
PubMed1989

Effect of dietary thyroxine on growth and muscle protein metabolism in broiler chickens.

The effects of thyroxine (T4) on growth, feed efficiency, breast muscle (Musculus pectoralis profundus) weight, liver weight, abdominal fat content, and rates of muscle protein synthesis (Ks) and breakdown (Kd) estimated by N tau-methylhistidine excretion were investigated in broiler chickens of both sexes. Dietary inclusion of .4 ppm T4 resulted in a less abdominal fat content in female chickens and a higher muscle protein synthesis rate in male chickens. Administration of T4 at the level of 1.2 ppm produced higher feed efficiency in both sexes and greater muscle weight and muscle protein synthesis rate in male chickens. This treatment also produced less abdominal fat content in female chickens. Administration of T4 at the level of 3.6 ppm produced lower body weight gain, breast muscle weight, liver weight, and abdominal fat content in both sexes and both higher protein synthesis and breakdown in skeletal muscle in male chickens. These experiments demonstrated that the abdominal fat content could be successfully reduced by dietary inclusion of T4, especially in female broiler chickens. The findings in the present investigation suggested that the improved feed efficiency and muscle growth were largely accomplished by the increase in muscle protein synthesis induced by the dietary inclusion of thyroxine.

Abdomen↗