[A case of congenital absence of the major pectoralis muscle].
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Adult↗
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Post-mortem biochemistry of Pekin duckling and broiler chicken Pectoralis muscle.
Biochemical post-mortem changes between red and white avian muscle were determined using duckling and chicken Pectoralis muscles, respectively. Six live Pekin ducklings and six live broiler chickens, in each of two trials, were obtained from commercial plants and processed at a pilot facility. After evisceration, carcasses were held at 4 C, then Pectoralis muscles were removed at .25, 1, 4, and 24 h post-mortem, and sampled for pH, lactate, adenosine triphosphate (ATP) content, and R-value (inosine to adenine ratio). Duckling Pectoralis pH significantly (P less than .05) decreased from 6.25 to 5.66 from .25 to 24 h post-mortem, respectively, as compared with that of the chicken, which decreased from 6.41 to 5.62 for the same times. Duckling lactate values, from .25 to 24 h, increased from 15.86 to 28.86 mumol/g, respectively, and chicken lactate values increased from 27.62 to 53.51 mumol/g. The ATP content of the duckling Pectoralis muscle decreased from 1.59 to .14 mumol/g and chicken Pectoralis decreased from 3.42 to .21 mumol/g from .25 to 24h, respectively. The R-values of duckling and chicken Pectoralis significantly increased from .25 to 24 h (.98 to 1.37 and .80 to 1.51, respectively). Duckling and chicken biochemical measurements were significantly different at all post-mortem sampling times, except for 24-h values of pH (5.66 versus 5.62, respectively) and 24-h contents of ATP (.14 versus .21 mumol/g, respectively). The different post-mortem biochemical measurements between duckling and chicken Pectoralis muscle is evidence that different rates of post-mortem metabolism and rigor development exist between these red and white avian breast muscles.
Adenine↗
The composite structure of quail pectoralis muscle.
The twitch fibers of the quail pectoralis muscle were found to have one neuromuscular junction each, located in the middle third of the fiber. The length of isolated fibers varied between 8.8 and 33.2 mm, with mean and median values of 16 and 15.6 mm, respectively. The lengths of the fascicles from which the fibers were isolated varied between 30 and 51 mm. The muscle fibers taper at both ends. The neuromuscular junctions, revealed after histochemically reacting the intact muscle for acetyl cholinesterase activity, were arranged in discrete bands, separated by intervals of between 0.94 and 6.70 mm, with a mean value of 3.14 mm. The quail pectoralis muscle is thus composed of discontinuous, tapered muscle fibers, arranged in an overlapping series. It is therefore a muscle in which tension is transmitted laterally between muscle fibers.
Acetylcholinesterase↗
Turnover of glycogen phosphorylase in the pectoralis muscle of broiler and layer chickens.
Glycogen phosphorylase is a major sarcoplasmic protein in chicken pectoralis muscle, constituting approx. 4% of the total protein complement. In slow-growing layer chicks phosphorylase accumulated in parallel with muscle accretion, but in fast-growing broiler chicks the concentration of phosphorylase in the muscle increased (from 5 to 8 mg/g wet wt.) with time. In a 5-week period, the total amount of phosphorylase in the pectoralis muscles increased 18-fold in broiler chicks (from approx. 75 to 1400 mg total), but only 3-fold (from approx. 100 to 270 mg total) in layers. Pyridoxal phosphate, the cofactor of the enzyme glycogen phosphorylase, was used as a specific label to measure the rate of degradation of the enzyme in the pectoralis muscle of growing broiler and layer chickens in vivo. In young animals, the fractional rate of phosphorylase synthesis was similar in broiler and layer chickens (approx. 15%/day), but the rate of degradation in layers (5%/day) was 5-fold higher than in broilers (1%/day). As the animals aged, the rate of synthesis decreased, but more so in layers than in broilers. The rate of degradation of phosphorylase also decreased in layers, but in broilers it remained at the low level seen in young animals. The dramatically higher rate of phosphorylase accretion in the pectoralis muscles of the broilers is therefore achieved by an initial lower rate of degradation combined with a sustained difference between rates of synthesis and degradation.
Aging↗
Analysis of tcRNA102 associated with myosin heavy chain-mRNPs in control and dystrophic chick pectoralis muscle.
Translational control RNA (tcRNA102) is closely associated with nonpolysomal myosin heavy chain-mRNA in mRNP particles. The nucleotide sequence of tcRNA102 has revealed a heterogeneity at the 3' end. This heterogeneity is mostly with regard to an ambiguity between adenine and guanine residues. tcRNA102 (obtained from pectoralis muscle) runs as a single band on denaturing acrylamide gels. When this band is extracted and rerun on a native gel at low voltage, two individual bands appear (A the slower moving and B the faster moving). From the partial RNase U2 sequence analysis and our previous sequence determinations (McCarthy, T. L., Siegel, E., Mrockowski, B., and Heywood, S. M. (1983) Biochemistry 22, 935-941), we may now assign tcRNA102 (A) the 3'-terminal sequence ... GGUUGGACGG-3' and tcRNA102(B) and 3' terminal sequence ... GAUUAAGCAA-3'. Analysis of the tcRNA102s indicates that dystrophic pectoralis muscle contains much less tcRNA102 than a similar preparation from control muscle. The tcRNA102 found in dystrophic pectoralis muscle is of the "A" type while normal pectoralis muscle contains predominantly the "B" type. In addition, control leg muscle from dystrophic chick contains predominantly "B" type. These results suggest that the differences observed at the DNA level (see accompanying paper, Zezza, D. J., and Heywood, S. M. (1986) J. Biol. Chem. 261, 7455-7460) may be reflected in the RNA transcripts.
Animals↗
On the heterogeneity of capillaries of pigeon pectoralis muscle: a histoenzymatic and ultrastructural study.
Earlier studies had failed to show the presence of capillaries between the white fibres of pigeon pectoralis muscle. In this paper, data are reported for the first time documenting that these capillaries occur in both intra- and inter-fasicular areas of the muscle. Fresh frozen sections of pigeon pectoralis major muscle were incubated for alkaline ATPase reaction following pretreatment with different EDTA solutions (4.3 mM, pH 4.3). The results showed the existence of an inherent heterogeneity of capillaries. The capillaries of white fibres stained intensely for K+/Mg2+-EDTA or Mg2+-EDTA pre-incubated ATPase; the capillaries of red fibres stained poorly. Both white fibre and red fibre capillaries were examined ultrastructurally in the non-perfused pigeon pectoralis muscle. It is suggested that a possible correlation exists between the distinctive metabolic and mechanical characteristics of the Type II white, glycolytic, fast-twitch fast-fatigue muscle fibres and the high ATPase activity of their capillaries.
Adenosine Triphosphatases↗
Histochemical characterization of the red fibres in pigeon pectoralis muscle.
Red fibres of the pigeon pectoralis muscle showed high ATPase reaction at pH 9.4. Veronal-acetate pretreatment completely inhibited the ATPase reaction in these red fibres but not in type I fibres of the gastrocnemius. The former are type II red muscle fibres and hence are unlike type I red, the so-called slow-twitch muscle fibres.
Adenosine Triphosphatases↗
Pectoralis muscle uptake of thallium-201 after arm exercise ergometry. Possible confusion with lung thallium-201 activity.
Pectoralis muscle uptake of thallium-201 was noted in 8 (73%) out of 11 patients after exercise arm ergometry. Uptake varied from mild to marked and potentially could be confused with pulmonary Tl-201 activity with a resulting false-positive diagnosis of exercise-induced left ventricular dysfunction. The three patients exhibiting negative or trace Tl-201 uptake had suboptimal exercise efforts. The characteristics of pectoralis muscle Tl-201 uptake are illustrated, and differentiation from true lung Tl-201 activity is discussed.
Arm↗
The preservation of minor pectoralis muscle in axillary dissection for breast cancer: functional and cosmetic evaluation.
We have evaluated, in two groups of 50 patients each submitted to axillary dissection for breast cancer (10 mastectomies and 90 conservative procedures), the advantage of the preservation of the minor pectoralis muscle. This muscle was preserved in one group and removed in the other. Whereas in the immediate postoperative period complications (shoulder pain, functional impairment, quantity or duration of serum drainage from the axilla) were the same in the two groups, at longer follow-up (more than 6 months after surgery) the patients whose pectoralis minor muscle was preserved showed a reduction in the incidence of partial atrophy and fibrosis of the pectoralis major muscle. Patients treated with conservation of the pectoralis minor muscle showed this atrophy in 6% of cases vs 54% observed in the other patients. This fact may be related to disruption of the pectoral nerves, which are in close contact with the pectoralis minor during their course from the brachial plexus to the pectoralis major muscle.
Axilla↗
Selective denervation of the Musculus pectoralis muscle in the chicken.
A surgical method for selective denervation was developed to facilitate investigations about the postmortem characteristics of denervated pectoralis muscles in chickens, Musculus (M.) pectoralis. The M. pectoralis was denervated in anesthetized chickens unilaterally or bilaterally by excising a 1-cm section of the nervus pectoralis as it branched from the N. medianoulnaris in the brachial plexus. Denervation resulted in significant (P less than .01) and consistent depression in the relative weight of M. pectoralis from the wk 2 through 17 postoperative. The relative weight of the functionally antagonistic M. supracoracoideus was unaffected by ipsilateral denervation of the M. pectoralis. The M. coracobrachialis acts in synergism with the M. pectoralis and displayed significant muscle atrophy at 4, 6, 8 and 17 wk postoperative in treatment groups where the ipsilateral M. pectoralis was denervated. Only the M. pectoralis displayed histological signs of denervation in transverse cryostat sections. Denervated tissue was characterized by atrophic and rounded muscle-fiber profiles, an increase in the endomysial and perimysial connective-tissue spaces, and leucocytes within degenerative perimysial nerves from 2 through 17 wk postoperative. Signs of denervation were distributed throughout seven zones sampled from the M. pectoralis. This study indicated that selective denervation of the M. pectoralis was achieved and that postoperative histology was necessary to accurately assess denervation.
Animals↗
Regulation of glycolysis in the pectoralis muscles of seasonally acclimatized American goldfinches exposed to cold.
Regulation of glycolysis was assessed in winter- and summer-acclimatized goldfinches (Carduelis tristis). We exposed birds to a thermo-neutral temperature (30 degrees C), moderate cold (-15 degrees C), and severe cold (0 degrees C in an atmosphere of 21% O2-79% He), and then measured concentrations of glycogen, glycolytic intermediates, and citrate in the pectoralis muscles. Winter birds used less glycogen when exposed to moderate cold than did summer birds, confirming the carbohydrate sparing noted by Marsh and Dawson [Am. J. Physiol. 242 (Regulatory Integrative Comp. Physiol. 11): R563-R569, 1982]. However, depletion of muscle glycogen did not correlate with thermoregulatory failure in this study. Concentrations of glucose 6-phosphate and fructose 6-phosphate in the pectoralis muscles were approximately 1.9 and 0.3 mumol/g wet mass in birds exposed to thermoneutral temperatures. The levels of these intermediates fell 50-70% under conditions known to enhance flux through glycolysis as indicated by increased glucose turnover and glycogen depletion. This information identifies phosphofructokinase (PFK) as a major regulated step in glycolysis in these highly aerobic skeletal muscles. Winter birds maintained the inhibition of this step under conditions of moderate cold. However, concentrations of citrate, which have been hypothesized to be an important inhibitor of PFK, did not correlate with the observed pattern of inhibition. Therefore, if the enhanced beta-oxidative capacity of winter birds is important in the regulation of glycolysis, a mechanism other than the accumulation of citrate may be involved.
Acclimatization↗
Myosin light chain 3 synthesis during chick pectoralis muscle development in ovo.
The level of myosin light chain 3 (LC3) in vertebrate skeletal muscle is developmentally regulated in a tissue-specific manner. We have used the RNA-cDNA hybridization assay to quantitate LC3 mRNA levels at various stages of chick pectoralis muscle development in ovo. The LC3 mRNA was found significantly in breast muscle only on Day 16 in ovo and later, the level of mRNA ranging from about 30 to 32% of that present in adult tissue. These values are in good agreement with the corresponding levels of LC3 in embryonic muscle. These results do not support the earlier reports that the protein and mRNA for LC3 accumulate in a noncoordinate manner in embryonic pectoralis muscle and they suggest that LC3 synthesis in ovo is regulated primarily at the transcriptional level.
Animals↗
M-protein from chicken pectoralis muscle: isolation and characterization.
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Amino Acids↗
Morphometric analysis of capillary geometry in pigeon pectoralis muscle.
The objective of the study was to examine the relationship(s) between the size and the geometry of the capillary network in the flight muscle of pigeon (Columbia livia). To this end, we used morphometry to analyze the degree of anisotropy (i.e., orientation) of capillaries with respect to the axis of the muscle fibers in perfusion-fixed samples of pigeon pectoralis muscles with large difference in capillary density. Capillary number per fiber cross-sectional area (range, 1,491-5,680 mm-2) depended on fiber size (aerobic fibers, 304-782 microns 2; glycolytic, 1,785-2,444 microns 2), as well as sarcomere length (1.69-2.20 microns), and the relative sectional area of aerobic and glycolytic fibers (aerobic, 42-84% of total fiber area). The degree of tortuosity of capillaries, i.e., their bending or sinuosity relative to the muscle fiber axis, was primarily a function of sarcomere length. In spite of large differences in capillary density, capillary orientation at a given sarcomere length was remarkably similar among samples. In addition to capillaries running parallel to the muscle fiber axis, a unique arrangement of branches running perpendicular to the muscle fiber axis was found in all samples. This arrangement yielded a large circumferential distribution of capillary surface around the muscle fibers. Compared to mammalian limb muscles examined over a 10-fold range of capillary density (range, 450-4,670 mm-2), the degree of anisotropy of capillaries was greater in all samples of pigeon M. pectoralis. In the pigeon, there was no increase in the amount of capillary surface area available for exchange per microvessel as a result of a greater degree of capillary tortuosity in samples with larger capillary density (capillary number per fiber cross-sectional area greater than 4,000 mm-2), as compared to samples with a capillary density less than 4,000 mm-2.
Animals↗
Acidic and basic protein contents in Gastrocnemii and pectoralis muscles of chick under denervation and work-induced stress conditions.
Biochemical estimation of acidic and basic proteins of chick gastrocnemii (G. externus, G. medius and G. internus) and pectoralis muscles has been done under normal, denervated and work stress conditions from 1-56 days of postnatal growth. The reciprocal relationship of the two protein groups is clearly established. It is evident that muscle denervation acts as a stimulant for proteosynthetic activities and probably may also be an inhibitory factor for protein degradative reactions. During work overload stress, the rapid growth of muscles has been related to high rate of contractile activity.
Animals↗
Congenital absence of the pectoralis muscles in two collegiate wrestling champions.
Deficiency of the pectoralis major is a relatively common muscle anomaly. There is little documentation, however, of what, if any, functional deficit the anomaly imparts. Therefore, two highly successful amateur wrestlers with unilateral congenital absence of the pectoralis minor and sternocostal head of the pectoralis major are reported. Cybex testing revealed no appreciable decrease in shoulder internal rotation strength but did show a 20%-30% decrease in shoulder horizontal adduction strength. Other patients similarly affected can be advised that their shoulder strength will be slightly decreased, but significant functional limitations are unlikely.
Adult↗
Sequential expression during postnatal development of specific markers of junctional and free sarcoplasmic reticulum in chicken pectoralis muscle.
Skeletal muscle sarcoplasmic reticulum comprises two distinct membrane domains, i.e., the Ca(2+)-pump membrane, corresponding mainly to longitudinal tubules, and the junctional membrane of the terminal cisternae containing the ryanodine receptor/Ca(2+)-release channel. Additional minor proteins previously shown in rabbit fast-twitch skeletal muscle to fractionate selectively to each membrane domain comprise 160- and 53-kDa glycoproteins and 170-kDa low-density lipoprotein (LDL)-binding protein, respectively (Damiani and Margreth, 1991, Biochem. J. 277, 825-832). We report evidence in chicken pectoralis, a predominantly fast muscle, on two closely immunologically related glycoproteins, a minor component of 130-kDa and a major 53-kDa protein. In contrast to the seemingly highly conserved structure of this protein, our results show marked differences in mobilities for chicken 125I-LDL that were detected as a 130- to 116-kDa protein doublet after sodium dodecyl sulfate-polyacrylamide gel electrophoresis, although being otherwise indistinguishable from rabbit 170-kDa protein in LDL-binding characteristics, as well as for preferential association to junctional terminal cisternae. Chicken Ca(2+)-ATPase, although being extensively homologous to rabbit Ca(2+)-ATPase, is shown to be less active and to differ slightly in electrophoretic properties. We have investigated the time course of expression of the specific protein components of longitudinal and of junctional sarcoplasmic reticulum in chick pectoralis muscle from late embryonic development up to 2 months after hatching. Coincident with the posthatching increase in membrane density of high-affinity [3H]ryanodine-binding sites in muscle, both calsequestrin and the species-specific LDL-binding protein(s) are detected in increasing amounts, using ligand blot techniques. In contrast, the appearance and steady accumulation in muscle of Ca(2+)-ATPase, like the time-correlated increase of sarcoplasmic reticulum glycoproteins, are relatively delayed, the most striking changes occurring from 1 week after hatching onward. The sequential expression in chick developing muscle of proteins selectively associated with the junctional terminal cisternae and with longitudinal sarcoplasmic reticulum, respectively, argues for a similar morphogenetic program in avian and mammalian species and, to account for that, for the existence of common epigenetic differentiating influences on the expression of sarcoplasmic reticulum protein genes.
Animals↗
[Influence of pectoralis muscle potentials on R-inhibited unipolar pacemakers].
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Action Potentials↗