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At least 37 records · Page 2Linked to original sources
PubMed2003

Pectoralis muscle flap reconstruction of pediatric sternal wound infections.

Sternal wound infection (SWI) is a life-threatening complication in both the pediatric and adult population. The morbidity and mortality of SWIs have decreased with the use of muscle flap reconstruction of the chest wall. Although the pectoralis muscle flap is the most frequently used flap in adults for reconstruction after SWI, its use in children has not been well described. To review current experience with the use of the pectoralis muscle flap in a pediatric population, a retrospective review of 1,200 consecutive median sternotomies occurring at the Children's Hospital of Pittsburgh between 1992 and 1997 was performed. All cases of postoperative SWI were identified, and the operative management was performed by a single surgeon. Reconstruction was performed with the use of unilateral or bilateral pectoral muscle flap advancements. Sternal wound infections developed in nine patients (0.75% incidence). The mean duration from initial sternotomy to the time of presentation of deep SWI was 39.5 days. Eight patients underwent reconstruction using pectoralis muscle advancement flaps. Two patients (25%) were reconstructed with a unilateral pectoralis advancement flap, whereas six patients (75%) required bilateral advancement flaps. One patient was treated with conservative management. The average length of stay after reconstruction was 9 +/- 4 days. Duration of follow-up ranged from 3 to 42 months (mean: 16 +/- 12 months). All reconstructions ultimately resulted in well-healed wounds with satisfactory cosmesis. No developmental or functional deficits have been documented in follow-up visits. Sternal wound infection is a serious postoperative complication of median sternotomy. Aggressive operative management with the use of muscle flap reconstruction has helped to lower the morbidity and mortality of this infection. The successful use of pectoralis muscle flap advancement for functional and esthetic reconstruction of the chest wall in children is described.

Child↗
PubMed1983

Alteration of sarcoplasmic reticulum after denervation of chicken pectoralis muscle.

To determine the neural influence on the function of the sarcoplasmic reticulum (SR) of fast-twitch skeletal muscle, the superior pectoralis muscle of adult chicken was denervated, and the SR was isolated at 20 days post-denervation. The isolated SR was probably derived from the longitudinal SR and was relatively free of contaminants. The protein profile of the SR was quantitatively changed after denervation with an increase in the M55 and 30000-mol.wt. proteins relative to the Ca2+-ATPase. Ca2+-dependent ATPase activity and phosphoenzyme formation were lower in the denervated-muscle SR; however, the enzyme catalytic-centre activity was similar to the control value. The decrease in Ca2+-ATPase activity in denervated-muscle SR was accompanied by a lower Ca2+ accumulation so that the relationship between Ca2+ accumulation and Ca2+-dependent ATPase activity was well maintained in the SR from denervated muscle. The data imply that denervation may result in a diminution of functional Ca2+ pump sites. Evidence is presented, though, which suggests that denervation affects a single class of Ca2+-binding sites of the Ca2+-ATPase, resulting in a lower affinity for Ca2+.

Adenosine Triphosphatases↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1994

Ontogeny of the pectoralis muscle in the little brown bat, Myotis lucifugus.

The ontogeny of a primary flight muscle, the pectoralis, in the little brown bat (Myotis lucifugus: Vespertilionidae) was studied using histochemical, immunocytochemical, and electrophoretic techniques. In fetal and early neonatal (postnatal age 1-6 days) Myotis, histochemical techniques for myofibrillar ATPase (mATPase) and antibodies for slow and fast myosins demonstrated the presence of two fiber types, here called types I and IIa. These data correlated with multiple transitional myosin heavy chain isoforms and native myosin isoforms demonstrated with SDS-PAGE and 4% pyrophosphate PAGE. There was a decrease in the distribution and number of type I fibers with increasing postnatal age. At postnatal age 8-9 days, the adult phenotype was observed with regard to muscle fiber type (100% type IIa fibers) and myosin isoform profile (single adult MHC and native myosin isoforms). This "adult" fiber type profile and myosin isoform composition preceded adult function by about 2 weeks. For example, little brown bats were incapable of sustained flight until approximately postnatal day 24, and myofiber size did not achieve adult size until approximately postnatal day 25. Although Myotis pectoralis is unique in being composed of 100% type IIa fibers, transitional fiber types and isoforms were present. These transitional forms had been observed previously in other mammals bearing mixed adult muscle fibers and which undergo transitional stages in muscle ontogeny. However, in Myotis pectoralis, this transition transpires relatively early in development.

Aging↗
PubMed1983

Myosin isozymes in avian skeletal muscles. I. Sequential expression of myosin isozymes in developing chicken pectoralis muscles.

Myosin has been purified from chicken pectoralis muscle at various stages of development, from 10 days' incubation to approximately 10 months after hatching. Embryonic myosin from the earliest stage showed a high level of ATPase activity, similar to that obtained for adult pectoralis myosin. Two-dimensional peptide mapping of partial chymotryptic digests showed, however, that is heavy chain is quite different from that of adult fast myosin. The immunological crossreactivity observed between embryonic myosin and adult fast (pectoralis) myosin is therefore due to shared antigenic determinants rather than the presence of any adult isoforms. In an accompanying paper we will show that embryonic myosin at 10 days' incubation is not a single species, but consists of at least two heavy chain isozymes. The minor fraction binds slow light chains preferentially, and appears to be largely responsible for the observed crossreactivity with slow (ALD) myosin. None of the embryonic myosins is equivalent to the adult forms. Prior to hatching, LC3f is present only in very small amounts (less than 5%), and the adult light chain pattern, containing LC1f and LC3f in equimolar amounts, is not generated until after one week post-hatching. At about that time a new heavy chain population is detected, different from either the embryonic heavy chain or the adult heavy chain. The adult heavy chain peptide pattern appears from about three weeks' post-hatching, but a map indistinguishable from that of adult myosin is not observed until about 26 weeks. None of the observed differences in peptide maps can be related to different strains of chicken; pectoralis myosin from adult White Rock gave an identical map to that from White Leghorn. Unexpectedly, posterior latissimus dorsi (PLD) myosin from White Leghorn appears to be different from pectoralis myosin from the same strain, despite the histochemical and immunocytochemical similarity of the two muscles. We conclude that myosin polymorphism is widespread in muscle tissue, and that the expression of myosin isozymes and their subunits is under developmental regulation.

Adenosine Triphosphatases↗
PubMed1983

Seasonal acclimatization in American goldfinches: the role of the pectoralis muscle.

The present study attempts to assess whether the marked seasonal changes in the capacity for shivering thermogenesis in American goldfinches (Carduelis tristis) involve adjustments of metabolic pathways of the pectoralis muscles similar to those observed in mammalian muscle in response to endurance training, i.e., changes favoring increased reliance on fatty acid oxidation and decreased utilization of carbohydrate reserves. Analysis of seasonal changes in enzyme profile of the pectoralis muscle revealed that winter-acclimatized birds have significantly greater (P less than 0.05) activities of phosphorylase, phosphofructokinase, and beta-hydroxy-acyl-CoA dehydrogenase than do birds in other seasons. The activities of citrate synthase and hexokinase do not vary seasonally. These results differ fundamentally from the pattern of changes in enzyme activities associated with endurance adaptation in mammals. Furthermore no seasonal changes were observed in capacities for the oxidation of fatty acids (palmitate and linoleate) or pyruvate in either crude homogenates or isolated mitochondria of goldfinch pectoralis muscles. The oxidation of pyruvate by isolated pectoralis muscle mitochondria was inhibited (greater than 90%) by the oxidation of palmitoyl carnitine at palmitoyl carnitine concentrations as low as 50 microM. These data agree with physiological observations indicating little use of glucose by this tissue during steady-state shivering. However, the extent of this inhibition does not vary seasonally. Therefore the present study fails to document any significant seasonal change in the catabolic pathways of the pectoralis muscle that would link observed seasonal changes in capacity for shivering thermogenesis with a shift in the balance of substrate use by this tissue.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1993

Histochemical and myosin composition of vampire bat (Desmodus rotundus) pectoralis muscle targets a unique locomotory niche.

The vampire bat pectoralis muscle contains at least four fiber types distributed in a nonhomogeneous pattern. One of these fiber types, here termed IIe, can be elucidated only by adenosine triphosphatase (ATPase) histochemistry combined with reactions against antifast and antislow myosin antibodies. The histochemical and immunohistochemical observations indicate a well-developed specialization of function within specific regions of the muscle. In parallel, analyses of native myosin isoforms and myosin heavy chain isoforms indicate two points. First, the histochemical "type IIe" fiber is predominant in cranial portions of the muscle, and myosin extracted from these regions exhibits a unique electrophoretic mobility not observed in the myosin isoforms of more traditional laboratory mammals. Second, the type I fibers are confined to the pectoralis abdominalis muscle and a small adjacent region of the caudal part of the pectoralis. This pattern of type I fiber distribution is considered a derived character state compared to muscle histochemical phenotype and isoform composition in the pectoralis muscles of other phyllostomids we have studied (Artibeus jamaicensis, Artibeus lituratus, Carollia perspicillata). We relate this to the unique locomotory needs of the common vampire bat, Desmodus rotundus.

Animals↗
PubMed1986

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↗
PubMed1983

[Pectoralis muscles].

Origins, length, and insertion zones of the pectoralis muscles are described. The pocket of the pectoralis major and the square area of these muscles and some variations (Mm. sternales and the muscular arch) are included.

Adult↗
PubMed1995

[Relationships between differentiation characteristics of internal membrane systems and contractile properties in chicken pectoralis muscle].

Relationships between differentiation characteristics of internal membrane systems (transverse (T) tubules, sarcoplasmic reticulum (SR) and T-SR junctions (triad)) and contractile properties were investigated in developing (1 to 30 days after hatching) chicken pectoralis muscle. Internal membrane systems were visualized using calcium potassium- ferricyanide and lipid soluble fluorescent dye (DiIC16(3)) and observed by electron and confocal microscopes. Location of triads at the Z-line in pectoralis muscles differentiated in three steps: an initial location of longitudinally oriented triads at the A-I junction (15 days after hatching); a subsequent movement to the Z-line to keep the longitudinal orientation (20 days after hatching); finally rotation to a transverse direction on the Z-line and finishing the differentiation (30 days after hatching). Maximum shortening velocity (+60%) and maximum tension development (+100%) increased following 30 days development after hatching. However, the time courses of the increases in contraction speed and tension development were different. It is likely that the developing pectoralis muscle transiety expresses a protein responsible for adhesion of the triads to the myofibrils at the A-I junction region, and later substitutes that for a Z-line level protein. These separate stages in the differentiation of the E-C coupling units imply distinct cellular mechanisms underlying each of these events as well as their differential regulation during myogenesis in chicken skeletal muscle.

Animals↗
PubMed1979

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↗
PubMed1980

A histochemical and ultrastructural study of heterogeneous red fibres of pigeon pectoralis muscle.

The oxidative fibres of pigeon pectoralis muscle are 'type II red' on the basis of high myofibrillar adenosine triphosphatase (ATPase) and succinate dehydrogenase (SDH). The ATPase and SDH reactions do not characterize the heterogeneity of the red fibres in the normal pigeon pectoralis. Therefore, lipid, glycogen, phosphorylase, glycogen synthetase, SDH and ATPase reactions were studied in transverse sections of the pigeon pectoralis red fibre. This study has revealed the existence of an inherent heterogeneity between these red fibres. Three sub-populations distinguished were : (1) 'red1' fibres showing low fat but high glycogen and enzymes of glycogen metabolism (EGM); (2) 'red2' fibres displaying higher fat and higher amount of glycogen and EGM; and (3) 'red3' fibres possessing higher fat but lower content of glycogen and EGM. Ultrastructurally, one category of fibres (presumably red2 and red3) showed a higher concentration of fat; these fibres presumably possess higher synthetic capacity and lower (or higher?) utilization. Other mitochondria-loaded red fibres (presumably red1) documented here for the first time, showed fewer and smaller fat droplets indicating that they are 'predominantly lipid utilizers' and are incapable of storing large quantities of lipid. Moreover, the differing histochemical-ultrastructural attributes are presumably correlated with differences in levels of energetic metabolism, heat production and motor units of the red fibres.

Adenosine Triphosphatases↗
PubMed1997

Chronic hypoxia affects capillary density and geometry in pigeon pectoralis muscle.

We examined fiber capillarization and ultrastructure in pectoralis muscle of 11 pigeons (Columbia livia; body mass 603 +/- 12 (SE) g) i.e. nine birds kept at 3800 m for 5 months (three in a small aviary (A1) and five in smaller cages, A2) compared to three sea-level (SL) controls. There was no difference between groups in either the relative area or number of aerobic and glycolytic fibers per total fibers, fiber size or mitochondrial volume density. Hematocrit was significantly greater in A1 and A2 (59 +/- 1%) than SL (50 +/- 2%). In A1, capillary density relative to the sectional area of aerobic/total fibers, capillary diameter and the contribution of tortuosity and branching to capillary length were significantly greater than SL, yielding greater capillary length and surface area per volume of fiber. Capillary length and surface densities very close to those in A1 and significantly greater than SL for the relative sectional area of aerobic/total fibers were also found in four out of five A2 birds, without alteration in capillary geometry or diameter. The size of the capillary-fiber interface (i.e. capillary-to-fiber surface ratio) in aerobic fibers was also greater in A1 and A2 than SL, indicating a greater capacity for oxygen supply of the muscle fibers in the altitude groups.

Altitude↗
PubMed1978

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↗
PubMed1990

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↗
PubMed1994

Capillary-fiber geometry in pectoralis muscles of one of the smallest bats.

We previously reported striking similarities in the structural capacity for O2 flux in the highly aerobic flight muscles of a hummingbird and bat despite their significant differences in capillary-fiber geometry and number, and fiber size. However, the bats of that study (Eptesicus fuscus, BW 15-16 g) were about 5 times larger than the hummingbirds (Selasphorus rufus; BW 3-4 g). In this study, we examined the flight muscle in a bat of approximately the same size as the hummingbird to determine whether features found in the big brown bat would be accentuated or if there would be additional similarities with the hummingbird. The pectoralis muscle of pipistrelle bats Pipistrellus hesperus (BW 3-5 g) was perfusion-fixed in situ, processed for electron microscopy and analyzed by morphometry. Fiber size (group mean +/- SE, 314 +/- 22 microns 2 at 2.1 microns sarcomere length) and capillary geometry (high degree of tortuosity and branching) were remarkably similar to those in pectoralis muscle of the big brown bat. Thus distances from capillaries to the center of the fibers were not reduced in pipistrelle flight muscle (as in hummingbird) nor was capillary tortuosity and branching further increased (compared with big brown bat). Capillary-fiber surface ratio at a given mitochondrial volume/microns length of fiber was high and similar to that in big brown bat and hummingbird, consistent with the idea that the size of the capillary-fiber interface plays an important role in providing the great O2 flux potential in these muscles. In addition, capillary-fiber number at a given fiber mitochondrial volume per micron length of fiber was similar to that in other muscles including big brown bat and hummingbird flight muscle, bat hindlimb and rat M. soleus. This supports the notion of a close relationship between capillary number and mitochondrial volume on an individual fiber basis in aerobic muscles.

Animals↗