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Mild degree of Poland's Syndrome reconstruction with customized silicone prosthesis.

Poland's Syndrome consists of unilateral absence of the pectoralis major muscle, ipsilateral symbrachydaktylia, and occasionally associated other malformations of the anterior chest wall and breast. Mild Poland's Syndrome is characterized by asymmetry of the breasts with partial absence of the pectoralis major muscle. This report describes a 19-year-old man with unilateral hypoplasia of the breast, absence of the anterior axillary fold, and absence of the pectoralis major muscle. The patient's chest wall was reconstructed with a customized silicone prosthesis. This reconstructive technique is a simple alternative to more complex surgeries or muscle transposition.

Adult↗

The axillary arch: anatomy and suggested clinical manifestations.

The purpose of this commentary is to describe bilateral anomalous bands of the latissimus dorsi muscle observed in an 81-year-old male embalmed cadaver, and to discuss the possible clinical implications of this anomaly. The musculotendinous bands tautened and compressed the underlying axillary vessels, and the musculocutaneous, median, and ulnar nerves during passive abduction/external rotation of the shoulder. Similar variations found in the latissimus dorsi muscles in this commentary have been reported in the anatomical and surgical literature. These reports include descriptions of the anomalous bands of the latissimus dorsi attaching to the coracoid process, pectoralis major muscle, and fascia of the coracobrachialis muscle. The potential presence of an axillary arch presents several clinical considerations for the physical therapist. The existence of an axillary arch should be considered in patients with signs and symptoms consistent with upper extremity neurovascular compromise similar to thoracic outlet syndrome. Including this variant in the differential diagnostic process may assist physical therapists in the management of patients with signs and symptoms consistent with thoracic outlet syndrome.

Aged, 80 and over↗

Muscle protein turnover during early development in chickens divergently selected for growth rate.

To explore the mechanisms involved in the genetic control of muscle growth and protein gain, protein metabolism was assessed in the pectoralis major muscle of two chicken lines selected for either fast or slow growth. Protein synthesis was measured in vivo at various ages from 1 to 4 wk, using a flooding dose of L-[4-3H] phenylalanine. Protein degradation was estimated as the difference between synthesis and deposition. Over the experimental period, BW were about 2-fold greater (P < 0.001), and pectoralis major muscle weights were 2.4- to 3.6-fold higher (P < 0.001), in chicks from the fast-growing line (FGL) than those from the slow-growing line (SGL). Independent of age, absolute rates of protein deposition, synthesis, and breakdown were higher in FGL than in SGL chickens. Fractional rates of muscle protein synthesis clearly decreased with age. When comparing birds of the same age, fractional rates of muscle protein synthesis tended to be lower in the FGL. Fractional degradation rates (KD) were significantly lower in FGL chickens during the first 2 wk of post-natal growth, whereas KD were similar between lines in older chickens. In this experimental model of chicken lines divergently selected for BW, the greatest line-related difference in muscle protein metabolism was in KD, and was observed in the early growth phases.

Animals↗

Modified radical mastectomy sparing one or both pectoral muscles in the treatment of breast cancer: intra and postoperative complications.

CONTEXT AND OBJECTIVE: Modified radical mastectomy is widely utilized in breast cancer treatment. However, no prospective comparison has yet been made between the Madden technique (preservation of the pectoralis minor muscle) and the Patey technique (resection of this muscle). The aim of this work was to compare these two modified radical mastectomy techniques, by analyzing their degrees of difficulty and complications. DESIGN AND SETTING: Randomized trial at the Breast Unit of Hospital Araújo Jorge, Goiás; and Faculdade de Medicina da Universidade Federal de Goiás. METHODS: 430 patients with breast cancer with an indication for modified radical mastectomy were included in the program, of whom 426 patients were available for analysis (225 allocated to Patey and 201 to Madden). The chi-squared and Student t tests were used for analysis. RESULTS: The patients demographics were well balanced between the two groups. The mean duration of the surgical procedures was 105 (+/- 29.9) and 102 minutes (+/- 33), for the Patey and Madden groups, respectively (p = 0.6). Hospitalization duration was 2.3 days for both groups. The mean number of lymph nodes resected was 20.3 (+/- 7.6) for Patey and 19.8 (+/- 8.1) for Madden (p = 0.5). There were no differences in terms of vascular or nerve sections, hematomas or infections. The surgeons reported the same degree of difficulty for the two methods. CONCLUSION: The removal of the pectoralis minor muscle did not influence any of the variables studied. Therefore, either technique can be performed, at the surgeon's discretion.

Axilla↗

Effect of high-energy electron irradiation of chicken meat on thiobarbituric acid values, shear values, odor, and cooked yield.

Experiments were conducted to determine whether electron-beam irradiation would affect shear values, yield, odor, and thiobarbituric acid (TBA) values of chicken tissues. Broiler breasts (pectoralis superficialis) and whole thighs were irradiated with an electron-beam accelerator at levels to produce adsorbed doses of 100, 200, and 300 krads on the surface of the sample. The thigh samples were stored for 2, 4, and 8 days before testing for TBA values. The depth to which the radiation had penetrated the pectoralis superficialis muscle was also determined. Radiation penetrated 22 mm into slices of pectoralis superficialis muscle when 100 krad was absorbed by the surface of the tissue. The dose absorbed beneath the tissue surface to a depth of 10 mm was larger than the dose absorbed at the surface. The absorbed dose decreased as the depth of penetration increased. For cooked breast tissue, the shear values and moisture content were not affected by the absorbed radiation. Cooking losses of aged breast tissue were not affected by irradiation, but cooking losses were reduced in breast tissue that had not been aged. Irradiating uncooked thigh and uncooked breast samples produced a characteristic odor that remained after the thighs were cooked but was not detectable after the breast samples were cooked. With two exceptions, no significantly different TBA values were found that could be attributed to irradiation.

Animals↗

A histological study of post mortem changes in the skeletal muscle of the fowl (Gallus domesticus). II. The cytoarchitecture.

Changes in the histology of skeletal muscle at an ultrastructural level have been studied in the pectoralis thoracica and iliotibialis muscles of the fowl (Gallus domesticus). The carcasses were stored at 40 degrees C and samples removed at various times post mortem. The Z discs and I bands degenerate rapidly (less than 4 hours) but the thick filaments of the A band are remarkably resistant to change (greater than 24 hours). The sarcolemma, mitochondria, glycogen content, sarcotubular system and myonuclei also show marked changes in less than 4 hours. Myelin figures and autophagic vacuoles are among other features seen in post mortem tissue. There are more degenerate mitochondria and vesicular remnants of the sarcotubular system in the iliotibialis than in the pectoralis muscle, but this reflects a differing concentration of these organelles in vivo. No other consistent difference in the post mortem histology of these muscles has been observed.

Animals↗

Is ribosomal capacity a potential metabolic marker of muscle development? Measurement by muscular biopsy.

Metabolic markers of muscle metabolism could help geneticists and nutritionists predict the breast meat development of chickens. The aim of the current study was to test the ribosomal capacity (CS), a potential metabolic marker, and to evaluate a simple biopsy method on the pectoralis major muscle. Ribosomal capacity was measured in three commercial meat chicken genotypes differing in their growth rate. Fast-, medium-, and slow-growing male chickens were fed using three commercial dietary programs of increasing energy and protein concentration (nine treatments). Biopsy was performed at 4 wk of age on the p. major 12 chickens per treatment. Fast-, medium-, and slow-growing chickens were slaughtered at market weight, i.e., 6, 8, and 12 wk of age, respectively, and breast meat (right and left p. major + minor) was dissected. A significant reduction in BW at slaughter (-1 to -3%) and breast meat yield (-4%) occurred only in biopsied medium-growing chickens but not in the other two types. Slow-growing chickens had a significantly lower CS (8.75 microg/mg) than the two other chicken types (9.40 and 9.46 microg/mg for fast- and medium-growing chickens, respectively). No significant dietary effect or interaction of dietary treatment with genotype was measured. The CS was not significantly correlated to breast meat development. Under conditions of the present experiment, CS may not be a relevant marker of subsequent breast meat development at 4 wk of age. The biopsy technique can easily be applied to other markers.

Aging↗

Rectus abdominis as a source of myopotentials inhibiting demand pacemakers.

We examined four patients with a demand pacemaker who exhibited transient symptoms of vertigo while trying to rise from the supine position. In two of these there was an epicardial pacing system with the pacemaker in the abdominal wall superficial to the rectus abdominis muscle; in the other two cases the pacing system was transvenous with the pacemaker superficial to the right pectoralis major muscle. It was found that the "pseudovertigo" was due to pacemaker inhibition caused by rectus abdominis myopotentials in all four patients. Changing the pacing mode from the demand to fixed-rate resulted in the disappearance of all symptoms at rest and during exercise.

Abdominal Muscles↗

Identification of lipids as the main component of skeletal muscle Z-discs.

The existence of lipids in Z-discs of the vertebrate skeletal muscle was suggested by the results of microscopy using rhodamine 6G reagent, a fluorescent probe. After removal of lipids by treatment of myofibrils with 0.5% Trition X-100, intact configurations of Z-filaments composed of alpha-actinin were clearly visible under an electron microscope. These findings indicated that lipids were amorphous-matrix materials of the Z-disc. Lipids were proved to be the main component of Z-discs by their extraction from I-Z-I brushes with a mixture of methanol and chloroform and by analysing them. The total amount of lipids in Z-discs exceeded that of alpha-actinin and varied from 2.4 to 7.1 g per 100 g of myofibrillar proteins depending on the phenotype of skeletal muscle. The sum of the amounts of lipids and alpha-actinin was 4.5 g per 100 g of myofibrillar proteins in chicken pectoralis profundus muscle (fast type), while it was 10.1 g in chicken soleus muscle (slow type). Lipid classes were phospholipids, triacylglycerols, cholesterol and free fatty acids. Since the lipids extracted from I-Z-I brushes were hardly contaminated with those from the sarcoplasmic reticulum and mitochondria, their amounts and classes were considered to be characteristic of Z-discs. The lipids probably cement neighbouring Z-filaments electrostatically, reinforce the Z-disc structure, and play an important role in the force transmission of skeletal muscle myofibrils.

Actinin↗

Rupture of pectoralis major during parallel bar dips: case report and review.

Rupture of the pectoralis major muscle is an uncommon athletic injury that can result in both functional and cosmetic deficiency. To date, most ruptures occurring in athletes have occurred while performing bench press or overhead lifting maneuvers. We describe a case of a pectoralis major rupture occurring while performing weighted parallel bar dips. Despite the popularity of this exercise, injuries associated with this exercise are infrequently reported. This injury can be easily detected by having the patient perform specific maneuvers on physical examination to accentuate any defect that may be present. In most cases, this injury is surgically repaired, although conservative treatment can be a successful option. Treatment options are discussed and recommendations given. A partial or complete tear of the pectoralis major muscle is a rare event and is often not easily detected on physical examination. Surgical repair is currently recommended to restore previous levels of strength and to correct the resulting cosmetic defect. Repair is rarely necessary to perform the normal activities of daily living.

Adult↗

Management of sternal wounds with pectoralis major musculocutaneous advancement flaps in patients with a history of chest wall irradiation.

Although debridement and pectoralis major musculocutaneous advancement flap closure has proved to be an effective treatment of sternal wounds in the general population, the purpose of this study was to examine the use of these flaps in patients with previously irradiated chest walls. The authors examined 5 patients with a history of breast cancer and chest wall radiation therapy who developed poststernotomy wound complications that were treated with debridement and pectoralis major musculocutaneous advancement flaps. The average patient age was 76 years. Three patients had previously undergone a radical mastectomy and had only 1 pectoralis major muscle remaining. There were no intraoperative deaths. One patient died during the 30-day postoperative period. There were no hematomas, seromas, or dehiscences. One woman developed a postoperative wound infection. Functional and aesthetic results were excellent. This study demonstrates that early, aggressive sternal debridement and closure with pectoralis major musculocutaneous advancement flaps is effective in patients with a history of chest wall irradiation, including those who have had 1 pectoralis major muscle previously resected.

Aged↗

Reconstruction after median sternotomy infection.

Reconstruction after median sternotomy infections is a difficult problem. We have presented ten consecutive patients with a wide variety of underlying cardiac illnesses who have had this dreaded complication develop. All of these patients have undergone successful reconstruction after adequate debridement and elimination of the mediastinal dead space using a combination of well vascularized omentum and pectoralis major muscle flaps. Stability of the chest wall has been accomplished primarily with pectoralis major muscle flaps. Complications have been few, morbidity has been significantly reduced and mortality, thus far, has been eliminated, although we certainly have no expectations that it will remain so.

Adult↗

Effect of selection for growth rate on myosin heavy chain temporal and spatial localization during turkey breast muscle development.

The temporal and spatial localization of the heavy chain fast form of myosin was studied during turkey pectoralis major muscle development in a randombred control line (RBC2), a subline (F) of RBC2 selected only for increased 16-wk BW, a commercial sire line (B), and reciprocal crosses of the F and B lines. Pectoralis major muscle samples were obtained from three females and three males from each group in a manner to avoid contraction. After fixing and sectioning, the muscle samples were stained with a monoclonal antibody to determine the temporal and spatial localization of the heavy chain fast form of myosin. The percentage of muscle fibers at 25 d of incubation and 1 wk posthatch expressing the fast form of myosin heavy chain was calculated. The average percentage of muscle fibers expressing the fast form of myosin heavy chain for all genetic lines combined at embryonic d 25 for males was 76.1 and for females 66.6, whereas at 1 wk posthatch the average percentage for males was 24.2 and 36.1 for females. No interaction of sex and genetic group was noted at either age. At 25 d of embryonic development and at 1 wk of age, additive and nonadditive genetic effects were important in the inheritance of the fast form of myosin heavy chain. Heterosis was negative at both ages but significant at 1 wk of age. By 4 wk posthatch, all the muscle fibers in each genetic group were expressing the myosin heavy chain fast form, and no sex differences were observed. At 16 wk posthatch muscle fiber fragmentation was noted in the samples having reduced endomysial spacing. In the fragmenting muscle fiber areas, expression of the heavy chain fast form of myosin was observed. These muscle fiber changes were predominant in the growth selected F-line suggesting that growth selection may be associated with muscle damage.

Animal Husbandry↗

The case against medial pectoral releases: a retrospective review of 315 primary breast augmentation patients.

Although medial pectoral releases have been recommended as an important component of retropectoral breast augmentation surgery, there has been no study that documents the benefit or need for this potentially harmful surgical maneuver. In this study, 315 patients were retrospectively reviewed to determine the effect of medial pectoral muscle releases on breast implant position, visibility, and palpability. Five patients had incomplete data, leaving 310 patients available for photographic and clinical analysis at an average of 25.7 weeks postoperatively (range 5.61-91.6 weeks). All patients received textured, saline-filled, round, retropectoral implants. Group I (n = 163) had partial medial pectoral releases to the level of the superior aspect of the areola. Group II (n = 152) had no releases; however, retropectoral pocket dissection was extended medially to the arc of the median raphe, where the tendinous origins of the pectoralis major muscle are firmly anchored to the anterior aspect of the sternum. To assess implant position, the ratio of the intermammary space to the lateral breast protrusion (IMS/LBP) was compared for all patients. There was a greater decrease in the average IMS/LBP ratio in group II compared with group I, (P = 0.0315). This indicates that subpectoral mobilization to the arc of the median raphe afforded a proportionally decreased intermammary space, better medial envelope fill, and less lateral implant displacement when compared with medial pectoral releases. Five patients (3%, P = 0.014) developed breast implant visibility and palpability on the medial aspect of the breast mounds, and 2 patients (1.2%) developed hematomas in group I. One patient (0.6%) developed implant distortion with muscle flexion in group II. To explain these results, 6 pectoral muscles were dissected in 3 female cadavers. Above the fifth rib and below the clavicular head, the secure, tendinous origin of the pectoralis major muscle arises from the central anterior aspect of the sternum forming an "arc of the median raphe." This anatomic feature allows pectoral muscle mobilization medially, negating the need for division. Maintaining the integrity of the pectoral muscle affords decreased implant visibility and palpability medially and decreased patient morbidity while delivering possibly improved esthetic proportions by decreasing the intermammary space.

Adult↗

Effect of transforming growth factor-beta on decorin and beta1 integrin expression during muscle development in chickens.

Myoblast-extracellular matrix interactions play a pivotal role in skeletal muscle development. Transforming growth factor-beta (TGF-beta) is a key regulator of muscle cell proliferation and differentiation. The level of TGF-beta expressed will affect the concentration of the extracellular matrix proteoglycan decorin and the cell surface beta1 integrin subunit. The decorin proteoglycan is a regulator of cell growth as well as the organization of the extracellular matrix. The beta1 integrin plays a role in muscle cell attachment, migration, and the formation of multinucleated myotubes. In the current study, chicken myogenic satellite cells isolated from the pectoralis major muscle from the chicken genetic muscle weakness, low score normal (LSN), and normal pectoralis major muscle were used to investigate TGF-beta expression as it relates to decorin and beta1 integrin mRNA expression. The LSN muscle defect is characterized by altered myotube formation and sarcomere structure, and the satellite cells have reduced proliferation and differentiation. The mRNA expression was measured by real-time quantitative reverse transcription PCR. The LSN condition has elevated expression of TGF-beta2 and TGF-beta4 with increased expression of decorin and decreased beta1 integrin during myogenic satellite cell proliferation and differentiation. Normal satellite cell cultures were treated with the addition of exogenous TGF-beta during differentiation to determine if the altered expression of LSN decorin and beta1 integrin was associated with TGF-beta expression. The addition of exogenous TGF-beta decreased decorin expression during differentiation and reduced beta1 integrin expression at 24 and 48 h of differentiation. These results suggested that alteration of decorin expression in the LSN myogenic satellite cells may occur by a mechanism involving factors in addition to TGF-beta, but the addition of exogenous TGF-beta did affect both decorin and beta1 integrin expression. These data, therefore, suggested that TGF-beta might play a pivotal role in chicken skeletal muscle formation through modulation of the expression of both extracellular matrix molecules and cellular receptors important in the control of cell migration and growth regulation.

Animals↗

Effect of two stunning voltages on blood loss and objective texture of meat deboned at various post-mortem times.

Two experiments were conducted to determine the effect of different stunning voltages on the objective texture of the Pectoralis major muscles deboned at various post-mortem times. Broilers were stunned at either 50 or 200 V alternating current (VAC) for 10 s in a brine stunner. The artery and vein on one side of the neck were severed, blood collected for 90 s, and blood loss calculated as percentage of live weight. Carcasses were then processed under simulated commercial conditions. In the first experiment, the right and left Pectoralis major muscles were excised at 1 and 2 h post-mortem respectively, weighed, vacuum-sealed in plastic bags, and held overnight at 2 C. In the second experiment, the Pectoralis major muscles were excised at 4 h post-mortem and held overnight at 2 C. The muscles were then heated at 85 C for 30 min, equilibrated to room temperature, and prepared for Warner-Bratzler shear analysis. The stunning treatments did not significantly affect blood loss, which averaged 2.86 and 2.64% for 50 and 200 VAC, respectively. Birds subjected to the 50 VAC treatment had a mean shear value of 7.3 kg, which was significantly lower (P < .05) than the mean shear value of 10 kg for birds subjected to the 200 VAC treatment for muscles excised 2 h post-mortem. The use of 200 VAC for stunning could be used without any detrimental effect on the cooked meat as long as the standard deboning time of 4 h was maintained.

Animals↗