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At least 631 records · Page 35Linked to original sources
PubMed1996

The effects of stunning amperage and deboning time on early rigor development and breast meat quality of broilers.

Two trials were conducted to determine the effects of stunning amperage on the early rigor development and quality of broiler breast meat. In each trial, 108 broilers were killed either without stunning or following constant amperage stunning at 50 or 125 mA. The breast muscles (Pectoralis major) were removed from the carcasses at 0.2, 1, 2, 4, 6, 8, 10, 12, or 24 h post-mortem. Breast muscle pH and R-value (inosine to adenosine nucleotide ratio) were determined immediately upon deboning on one side of each carcass. After aging the deboned breast fillets for 48 h, cook loss and Allo-Kramer shear values were determined on the opposite side. Stunning at 50 or 125 mA resulted in significantly higher muscle pH values up to 6 h post-mortem, after which there were no further significant differences. Stunning at 50 and 125 mA resulted in significantly lower R-values up to 6 h post-mortem. Stunning had no effect on cook loss. Stunning at 125 mA resulted in significantly tougher meat up to 10 h post-mortem than meat from unstunned birds or birds stunned at 50 mA. These results indicate that the delayed onset of rigor, as measured by muscle pH and R-value, noted in electrically stunned birds lasts for approximately 4 to 6 h, after which differences due to stunning disappear.

Animals↗
PubMed1998

[Plastic reconstruction of the irradiated thoracic wall].

Chest-wall reconstruction following irradiation requires a surgical approach that addresses the specific healing disorders associated with irradiation: (1) biopsy of any open wound to rule out recurrence or persistence of tumor; (2) aggressive debridement of all necrotic or infected tissue, especially osteonecrosis of the chest wall; (3) reconstruction with well-vascularized muscle or musculocutaneous flaps. Coverage with muscle flaps provides a very reliable and effective single-stage reconstruction. Most types of flaps employed involve the latissimus, rectus abdominis and pectoralis muscle or musculocutaneous flaps. Rarely, stabilization of the thoracic wall is required, mostly facilitated by nonresorbable mesh. Respecting these principles, the irradiated chest wall can be reconstructed safely and with low morbidity. Plastic reconstructive techniques may also be employed safely to reconstruct the breast simultaneously in irradiated tissue by use of latissimus or rectus abdominis flaps.

Adult↗
PubMed1992

[Neo-angiogenesis after transplantation of a free skeletal muscle flap to the myocardium of the dog].

For the study of the process of neovascularization the effects of the transplantation of a free skeletal muscle flap on the heart of the dog were studied. For this purpose, in 14 mongrel dogs a myocardial infarction of the anterior wall of the heart was produced by the selective injection of microspheres into the left anterior descending artery. In 12 of those, on the area of infarction 4 weeks later a free pectoralis muscle flap was transplanted with its pars anterior in contact with the myocardium (group A). The arterial anastomosis was achieved with the internal mammary artery, the venous flow directed into the right atrium. In 2 other dogs (group B) the pectoralis flap was transplanted with irt pars anterior on a healthy myocardium. In 2 further dogs (group C) the pectoralis flap was transplanted on a infarcted myocardium with its pars posterior, i.e. the muscle fascia interponed. 16 weeks later a microcorrosion-cast-preparation and histological examinations showed in group A and B a prominent capillary network penetrating from the muscle into the myocardium, whereas in group C the muscle fascia inhibited this process. Thus, for the process of neovascularization the "bloody" contact between a skeletal muscle graft and the myocardium is necessary. Results are discussed with regard to possible factors inducing neoangiogenesis.

Anastomosis, Surgical↗
PubMed1993

Distribution of connectin (titin) and transverse tubules at myotendinous junctions.

The ends of muscle fibers form many longitudinal projections which are further divided into numerous processes and attach to the collagen fibrils of tendons to form myotendinous junctions (MTJs). Immunocytochemical and electron microscopic observations on pectoralis muscles of the chicken revealed the presence of an elastic filamentous protein, connectin (titin), within the terminal sarcomere on the side adjacent to the terminal Z bands, and the absence of connectin and myosin and the presence of actin at the apical sarcoplasmic region of MTJ processes between the terminal Z band and the MTJ sarcolemma. Intermediate voltage electron microscopy showed that T tubules in the terminal sarcomere were absent at the level of the A-I junction on the MTJ side in the rat vastus intermedius, and at the level of the terminal Z band or under the MTJ subsarcolemmal densities in the chicken pectoralis.

Animals↗
PubMed1983

An in vitro study of the interactions of skeletal muscle M-protein and creatine kinase with myosin and its subfragments.

Two proteins reported to be located in the M-band of skeletal muscle are M-protein (Mr 160,000) and creatine kinase (Mr 83,000). We have isolated and purified these proteins from adult chicken pectoralis muscle, and have studied their in vitro interactions with myosin, heavy meromyosin, light meromyosin and subfragment-2 in order to obtain a fuller understanding of the role these proteins play in the M-band of skeletal muscle. Experiments using the techniques of analytical ultracentrifugation, affinity chromatography and electron microscopy were carried out near physiological pH and ionic strength, under which conditions the M-band proteins are known to be firmly bound to the myofibril in situ. The results of our studies indicate that such interactions are either weak or absent in vitro. Discrepancies between our results and those from several other studies are discussed. We conclude that additional components may be required in order to observe interactions in vitro which are similar to those present in the intact myofibril.

Animals↗
PubMed1994

Coexistence of fast-muscle-type and slow-muscle-type troponin T isoforms in single chimeric muscle fibers induced by muscle transplantation.

Regenerated muscle fibers which appeared after transplantation of chicken slow muscle (anterior latissimus dorsi) into breast fast muscle (pectoralis major) of the same animal were studied by two-dimensional SDS-polyacrylamide gel electrophoresis, immunoblotting, and immunostaining with antisera against fast-muscle-type troponin T and slow-muscle-type troponin T. In the transplanted muscle, degeneration of muscle fibers was followed by regeneration of slow muscle, which was revealed by detecting slow-muscle-type troponin T with the antiserum. Furthermore, coexistence of fast-muscle-type and slow-muscle-type troponin T isoforms in single chimeric muscle fibers composed of partly fast and partly slow fibers was observed in the regenerated muscle. We suggested that the chimeric fibers were originated from the fusion of fast and slow myoblasts during regeneration after muscle transplantation and that two nuclei differently determined in troponin T expression were working independently in a single cell.

Animals↗
PubMed1991

The primary structure of skeletal muscle myosin heavy chain: III. Sequence of the 22 kDa fragment and the alignment of the 23 kDa, 50 kDa, and 22 kDa fragments.

The amino acid sequence of the 197-residue 22 kDa fragment from chicken pectoralis muscle was determined to be as follows: K-K-G-S-S-F-Q-T-V-S-A-L-F-R-E-N-L-N-K-L- M-A-N-L-R-S-T-H-P-H-F-V-R-C-I-I-P-N-E-T-K-T-P-G-A-M-E-H-E-L-V-L-H-Q-L-R- C-N-G-V- L-E-G-I-R-I-C-R-K-G-F-P-S-R-V-L-Y-A-D-F-K-Q-R-Y-R-V-L-N-A-S-A-I-P-E-G-Q- F-M-D-S- K-K-A-S-E-K-L-L-G-S-I-D-V-D-h-T-Q-Y-R-F-G-H-T-K-V-F-F-K-A-G-L-L-G-L-L-E- E-M-R-D- D-K-L-A-E-I-I-T-R-T-Q-A-R-C-R-G-F-L-M-R-V-E-Y-R-R-M-V-E-R-R-E-S-I-F-C-I- Q-Y-N-V-R-S-F-M-N-V-K-H-W-P-W-M-K-L-F-F-K, where h stands for 3-N-methylhistidine. The amino acid sequences of the 22 kDa fragment and its equivalent fragment from chicken ventricle and gizzard muscle myosins were also determined by our group. Predicted secondary structures of these 22 kDa fragment regions and of the reported chicken embryo myosin revealed some possible structural differences.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1982

Capillary supply of heart and skeletal muscle of small bats and non-flying mammals.

Capillary density (CD), fiber cross-section area, capillary-to-fiber ratio and intercapillary distance of papillary and a calf muscle were evaluated in four species of bats (body weight 23-150 g) and six non-flying mammalian species (2.5-170 g). In bats the pectoralis muscle was studied additionally. In both groups CD increased in papillary as well as in calf muscle with decreasing body weight. The papillary muscles showed the highest CD in the 2.5 g shrew Suncus etruscus (7287 cap./mm2) and the 23 g bat Myotis myotis (6748 cap./mm2). The flight muscle of the 38 g bat Molossus ater showed the highest CD (4992 cap./mm2) of all skeletal muscles investigated. The slopes of regressions of CD versus body weight for papillary (calf) muscles were -0.42 (-0.70) for bats and -0.15 (-0.26) for non-flying mammals, indicating that bats have a higher increase of weight-specific metabolic rate with decreasing body weight. This holds for species with a body weight below 30 g.

Animals↗
PubMed1978

Ultrastructural localization of acetylcholinesterase in cultured cells. III. DFP treated embryo muscle.

Brief treatment with 10(-4)M diisopropylfluorophosphate (DEP) irreversibly inactivates acetylcholinesterase (E.C.3.1.1.7; acetylcholine hydrolase) (AChE) activity in 10 day old chick embryonic muscle cultures. Electron microscopic cytochemistry was employed to follow the distribution of new AChE during recovery from DEP treatment. In normal 10 day cultures of embryo pectoralis muscles AChE is localized in the nuclear envelope, perinuclear sarcoplasm, sarcotubular system, subsurface vesicles and bound outside the cells. Immediately after DFP treatment AChE activity is absent in large myotubes. Within 15 min, activity is randomly present in small amounts in the sarcotubular system and nuclear envelope. There is a dramatic increase in activitv in the nuclear envelope during the 1st hr of recovery, and connections between the nuclear envelope and sarcotubular system are often seen. The next few hr of recovery show increased AChE activity. By 4 hr activity approaches that of controls. Six to 8 hr after treatment, AChE activity can be detected spectrophotometrically in the medium and can be seen bound outside the cells with the electron microscope. The spatial and temporal patterns of AChE activity demonstrate that the recovery of AChE and its mobilization and release from DFP-treated cells are not governed solely by the levels attained by the enzyme in the cultured embryo muscle.

Acetylcholinesterase↗
PubMed1984

Coexistence of fast-type and slow-type C-proteins in neonatal chicken breast muscle.

Two different C-protein variants which selectively react with either monoclonal anti-fast C-protein antibody (MF-1) or monoclonal anti-slow C-protein antibody (ALD-66) were separated from neonatal chicken pectoralis muscle by hydroxylapatite column chromatography. Myofibrils isolated from the neonatal chicken muscle reacted with both monoclonal antibodies as examined by an indirect immunofluorescence method. These observations strongly indicate that both fast-type and slow-type C-proteins are expressed in the neonatal chicken skeletal muscle. Both of them are intermingled and assembled in the same myofibrils.

Aging↗
PubMed1989

Expression of native rabbit light meromyosin in Escherichia coli. Observation of a powerful internal translation initiation site.

The cDNA-sequence coding for rabbit skeletal muscle light meromyosin (LMM) was placed under the control of the lambda promoter (PL) of an Escherichia coli expression vector. The resulting plasmid pEXLMM74 expressed non-fused rabbit skeletal muscle LMM with yields ranging from 1 to 5% of the total proteins of E. coli. This LMM was specifically recognized by polyclonal antibodies raised against chicken pectoralis muscle myosin. It could be highly enriched from E. coli extracts by using two cycles of high and low ionic strength buffer. The partially purified protein contained a major side-product, with a calculated molecular mass of 59 kilodaltons, that is produced by translation initiation from a site in the coding region of LMM. After deletion of the translation initiation site derived from the expression plasmid, only the 59 kilodalton protein is expressed in E. coli from the resulting plasmid pEXLMM59. Both the 74 and 59 kilodalton proteins were shown to form paracrystals. They were studied by electron microscopy using negative staining and were found to show characteristic striations with an axial periodicity of about 43 nm. By circular dichroism measurement we showed that the purified 59 kilodalton protein is folded mostly as an alpha-helix.

Animals↗
PubMed2006

Eliminating cardiac contamination from myoelectric control signals developed by targeted muscle reinnervation.

The electrocardiogram (ECG) artifact is a major noise contaminating the myoelectric control signals when using shoulder disarticulation prosthesis. This is an even more significant problem with targeted muscle reinnervation to develop additional myoelectric sites for improved prosthesis control in a bilateral amputee at shoulder disarticulation level. This study aims at removal of ECG artifacts from the myoelectric prosthesis control signals produced from targeted muscle reinnervation. Three ECG artifact removal methods based on template subtracting, wavelet thresholding and adaptive filtering were investigated, respectively. Surface EMG signals were recorded from the reinnervated pectoralis muscles of the amputee. As a key parameter for clinical myoelectric prosthesis control, the amplitude measurement of the signal was used as a performance indicator to evaluate the proposed methods. The feasibility of the different methods for clinical application was also investigated with consideration of the clinical speed requirements and memory limitations of commercial prosthesis controllers.

Adult↗
PubMed1990

Distinct vascular and intestinal smooth muscle myosin heavy chain mRNAs are encoded by a single-copy gene in the chicken.

We examined whether the gizzard MHC gene is expressed in other smooth muscle tissues and, if so, whether there exist any smooth muscle MHC isoforms at the mRNA level. Northern blot analysis showed that the gizzard MHC gene was also expressed in the aorta and jejunum, but not in the pectoralis muscle or in fibroblasts. This indicates that striated muscle and non-muscle MHC isoforms are encoded in genes distinct from the smooth muscle MHC gene. Further, nuclease S1 mapping showed that the aortic smooth muscle MHC mRNA was distinct from the gizzard mRNA in the 5'-terminal coding region. Both of these mRNA species are expressed in the jejunum. These observations suggest that there exist at least two chicken smooth muscle MHC isoforms, vascular-type and intestinal-type, and that these isoforms are generated from a single-copy gene, probably by an alternative mRNA processing mechanism.

Animals↗
PubMed1995

Efficacy of drug regimen exceeds electrostimulation in treatment of avian muscular dystrophy.

Autosomal-recessive dystrophic chickens were treated in three experimental groups with an intraperitoneal multicomponent drug mixture (50 mg/kg Ep475, 20 mg/kg Cinanserin, 10 mg/kg stanazolol, 100 mg/kg leucine, 0.1 mg/kg insulin, 100 mg/kg glucose, and 50 mg/kg carnitine), percutaneous high-frequency electrostimulation of the pectoralis muscle, or a combination of both drug and electrostimulation treatments. Therapeutic efficacy was determined in each group by measurements of strength, righting ability, and histomorphometric analyses of the pectoralis musculature. Drug treatment alone was found to significantly improve muscular strength, function, and relative myofiber necrosis compared with sham-injected controls. The efficacy of drug treatment was found to be equal to or better than singular electrostimulation treatment; there was no apparent additive effect of electrostimulation. As a result, these findings support the use of drug treatment as a useful nongenetic approach to the management of human muscular dystrophy where there is the potential risk of injury from exercise usage.

Age Factors↗
PubMed1993

Intermediate voltage electron microscopy of transverse tubules at myotendinous junctions.

The 3-dimensional distribution of transverse (T) tubules at myotendinous junctions (MTJs) was studied by intermediate voltage (400 kV) electron microscopy of thick sections of rat vastus intermedius and chicken pectoralis muscles stained with lanthanum nitrate. Transversely oriented T tubules were seen to run at the level of A-I junctions (the rat vastus intermedius) and Z bands (the chicken pectoralis), but were absent from such levels adjacent to the end of MTJ processes. These tubules opened to the lateral wall of sarcolemmal infoldings of MTJs and to the lateral cell surface. Longitudinally running T tubules were seen to connect with the transverse T tubules and to open at the bottom of junctional folds. The lack of T tubules at the final sarcomeric regions seems to indicate that the terminal sarcomeric half in close proximity to MTJs may be activated from the sarcoplasmic reticulum which forms couplings with the MTJ sarcolemma and/or longitudinal tubules in the MTJ processes.

Animals↗
PubMed2004

Immediate breast reconstruction with anatomical permanent expandable implants after skin-sparing mastectomy: aesthetic and technical refinements.

Use of anatomic permanent expandable implant after skin-sparing mastectomy (SSM) permits a 1-stage immediate breast reconstruction with an optimum breast shape. Preservation of most of the mammary skin after SSM on 1 side and anatomic prosthesis shape on the other makes breast reconstruction easier and enhances the quality of the esthetic results. The authors describe their experience with 40 immediate breast reconstructions after SSM performed over a period of 2 years explaining some technical details. The implant is placed in a submuscular pocket, or preferably, depending upon the condition of the muscles and skin flaps after mastectomy, in a submuscular-subfascial pocket. In this case, the undermining of the pocket is submuscular in its upper part under the major pectoralis muscle and subfascial in the lower part of the breast undermining the adipo-fascial tissues above the anterior serratus muscle. The submuscular dissection is done in continuity with the subfascial dissection to allow the complete closure of the soft tissues over the implant. In this case, the minor consistency of subfascial tissues compared with muscle in the inferior pole of the breast allows the easier and quicker distention of the soft tissue overlying the prosthesis during the inflation phase and ensures a good shape of the breast soon after surgery. Whenever possible, the mastectomy is performed through a periareolar skin incision that is closed with a purse-string suture. Finally, the authors discuss the indications of 2 different-shaped anatomic permanent expandable implants: full-height and short-height prostheses with different shape and fullness of the upper pole of the implant.

Adult↗
PubMed2004

Surface electromyography of nine shoulder muscles in two iron cross conditions in gymnastics.

AIM: The rules of gymnastics impose an element of static strength such as an iron cross (IC) on the rings. For IC training, coaches use a custom made device -- the herdos -- to simulate the conditions of competition. The purpose was to compare muscle activity and coordination during IC performed both on the rings and using herdos. Secondly, we tried to determine whether herdos usage induced functional adaptations of the shoulder muscles. METHODS: Six male gymnasts performed 10 IC in each condition. Surface electromyogram of muscles pectoralis major, latissimus dorsi, teres major, infraspinatus, rhomboideus, trapezius, serratus anterior, biceps brachii, and triceps brachii in the right shoulder were analysed using root-mean-square (RMS), and muscle part's in each condition. Muscle part represents the contribution of each of the 9 shoulder muscles studied in each condition. Total muscle activity (SUM) was also used to compare the 2 conditions. RESULTS: Except for the muscle teres major, the RMS decreases (p<0.05) when using the herdos. The SUM also decreases (p<0.05) when using this device. The muscle parts indicate that the contribution of the muscle latissimus dorsi decreases (p<0.05) when using the herdos. These results suggest that the herdos modified shoulder coordination. But their usage does not seem to induce any functional adaptations of these muscles. CONCLUSIONS: The herdos do not seem to provide a valid method to reproduce the same shoulder coordination as on the rings. Therefore IC training with this special device could be called in question.

Adult↗
PubMed1980

The biosynthesis of sarcoplasmic reticulum.

Muscle differentiation provides a slow-motion picture of the assembly of highly specialized sarcoplasmic reticulum endowed with Ca2+ transport activity from its constituents. During development of chicken embryo pectoralis muscle, the sarcoplasmic reticulum evolves from the rough endoplasmic reticulum of myoblasts by insertion of Ca2+ transport ATPase molecules synthesized on membrane-bound polysomes into the phospholipid-rich endoplasmic reticulum membrane. The process continues until the Ca2+ ATPase content of the membrane approaches physical saturation. The rate of synthesis of Ca2+ ATPase sharply increases after fusion of myoblasts into multinucleated myotubes and the accumulation of sarcoplasmic reticulum and myofibrillar proteins follows a roughly similar time course. The regulation of Ca2+ ATPase synthesis during development involves myogenic as well as neurogenic mechanisms. There are indications that changes in intracellular free Ca2+ concentration may play a role in this regulation.

Animals↗