Aggregation Of Myonuclei And The Spread Of Slow-tonic Myosin Immunoreactivity In Developing Muscle-spindles
Cell Biology; expression; fibers; heavy-chain isoforms; innervation; motor; rat; skeletal-muscle
The pattern of regional expression of a slowtonic myosin heavy chain (MHC) isoform was studied in developing rat soleus intrafusal muscle fibers. Binding of the slow-tonic antibody (ATO) began at the equator of prenatal intrafusal fibers where sensory nerve endings are located, and spread into the polar regions of nuclear bag2 and bag1 fibers but not nuclear chain fibers during ontogeny. The onset of the ATO reactivity coincided with the appearance of equatorial clusters of myonuclei (nuclear bag formations) in bag1 and bag2 fibers. Moreover, the intensity of the ATO reaction was strongest in the region of equatorial myonuclei and decreased with increasing distance from the equator of bag1 and bag2 fibers at all stages of prenatal and postnatal development. The polar expansion of ATO reactivity continued throughout the postnatal development of bag1 fibers, but ceased shortly after birth in bag2 fiber coincident with innervation by motor axons. Thus, afferents that innervate the equator might induce the slow-tonic MHC isoform in bag2 and bag1 fibers by regulating the myosin gene expression by equatorial myonuclei, and efferents or twitch contractile activity might inhibit the spread of the slow-tonic MHC isoform into the poles of bag2 but not bag1 fibers. Absence of ATO binding in chain fibers suggests that chain myotubes may not be as susceptible to the effect of afferents as are myotubes that develop into bag2 and bag1 fibers. The different patterns of slow-tonic MHC expression in the three types of intrafusal fiber may therefore result from the interaction of three elements: sensory neurons, motor neurons, and intrafusal myotubes.
Kucera J; Walro J M
Histochemistry
1991
1991
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1007/bf00315994" target="_blank" rel="noreferrer noopener">10.1007/bf00315994</a>
An Immunocytochemical Marker For Early-type-i Muscle-fibers In The Developing Rat Hindlimb
Anatomy & Morphology; Developmental Biology; expression; extrafusal; fibers; isoforms; mhc isoforms; muscle development; myosin heavy-chain; myotubes; skeletal-muscle; slow myosin; slow myosins; type i fibers
Muscle fibers develop sequentially from several generations of myotubes that express specific isoforms of myosin heavy chain (MHC). We observed that the chicken-derived monoclonal antibody (mAb) S46 binds to myotubes of the fetal rat hindlimb in a specific temporal and spatial pattern. To determine the type and fate of the S46-reactive myotubes, we immunoreacted sections of fetal, neonatal and postnatal hindlimb muscles to this antibody. The mAb S46 bound to a subpopulation of primary myotubes in the tibialis anterior, and to all primary and slow/fast secondary myotubes in the soleus muscle. The S46-reactive primary myotubes represented the oldest set of myotubes in the muscles. Reactivity to S46 was present from the earliest stages of muscle development, peaked in the late fetal period, and dissipated in the first postnatal week, suggesting that mAb S46 binds to a developmental form of slow myosin. The regional distribution of myotubes that bound S46 in fetal muscles was identical to the distribution of type I (slow-twitch) fibers in the adult, indicating that S46-reactive myotubes ultimately develop into type I extrafusal fibers. Thus, mAb S46 can be used as a marker for prospective type I extrafusal fibers in the rat hindlimb.
Kucera J; Walro J M
Anatomy and Embryology
1995
1995-08
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1007/bf00186002" target="_blank" rel="noreferrer noopener">10.1007/bf00186002</a>
Automated, Spatio-Temporally Controlled Cell Microprinting With Polymeric Aqueous Biphasic System
aqueous two-phase system; Biotechnology & Applied Microbiology; cell printing; coculture; fabrication; geometries; liquid; mammalian-cells; mechanisms; proliferation; scaffolds; skeletal-muscle; tissue
Cell printing is a promising approach to create organized constructs for tissue engineering applications. We present an automated cell printing microtechnology based on the use of an aqueous two-phase system (ATPS) interfaced with a three-axis motorized system. Cells suspended in the denser aqueous dextran (DEX) phase are loaded into printing tips, which are placed onto the cartridge of the motorized system. Using a computer interface, tips are lowered in the vicinity of a biological surface maintained in the immersion, aqueous polyethylene glycol (PEG) phase to perform a horizontal motion, autonomously dispense their contents onto the surface, and retracted out of the PEG phase. The motorized ATPS technology allows precise spatial and temporal control of the printing process and supports printing fully viable cells. We conduct a systematic study and show that the resolution of ATPS-mediated cellular patterns depends on several factors including the dimensions of the printing tips, lateral speed of tips during horizontal motion, and the loaded volume of the DEX phase in the tips. The finest resolution is mu 300 mu m obtained with a tip diameter of 200 mm at a printing tip speed of 16.5 mm/s. Higher speeds result in unstable DEX patterns that break into drops due to capillary instability, and thus are avoided. We also test a number of printing substrates and find that in addition to a cell monolayer, decellularized matrices can serve as a substrate for cell printing with ATPS. Using the principles from the characterization studies, we create duplex prints of cells to demonstrate the potential of this approach for spatio-temporally controlled cell placement. The ATPS printing microtechnology will be a step forward toward developing well-organized, three-dimensional tissue constructs. (C) 2013 Wiley Periodicals, Inc.
Petrak D; Atefi E; Yin L Y; Chilian W; Tavana H
Biotechnology and Bioengineering
2014
2014-02
Journal Article
<a href="http://doi.org/10.1002/bit.25100" target="_blank" rel="noreferrer noopener">10.1002/bit.25100</a>
Comparison Of Dopamine To Dobutamine And Norepinephrine For Oxygen Delivery And Uptake In Septic Shock
agents; cardiac-output; catecholamines; consumption; dobutamine; dopamine; General & Internal Medicine; hemodynamics; infusion; inotropic; intra-pulmonary shunt; lactic-acidosis; norepinephrine; oxygen consumption; septic shock; severe sepsis; skeletal-muscle; therapy; transport
Objectives: To test whether dopamine infusion improves oxygen delivery (D over dot O-2) and oxygen uptake (V over dot O-2) in hyperdynamic septic shock patients stabilized by adequate volume and dobutamine alone, or by the combination of dobutamine and norepinephrine. Design: Prospective clinical trial of two patient groups. Group 1 (n = 15) was stabilized with dobutamine, and group 2 (n = 10) was stabilized with dobutamine and norepinephrine. Setting: Intensive care unit in a university hospital. Patients: Twenty-five postoperative, hyperdynamic septic shock patients. Interventions: The stabilizing catecholamine infusion was replaced in a stepwise manner by dopamine to achieve a similar mean arterial pressure (dopamine doses: group 1, mean 22 +/- 15 mu g/kg/min [range 6 to 52]; and group 2, mean 57 +/- 41 mu g/kg/min [range 15 to 130]). Measurements and Main Results: A complete hemodynamic profile was performed with oxygen transport-related variables at baseline, after replacement by dopamine and after resetting to the original catecholamine infusion. The change to dopamine resulted in increases in cardiac index (group 1: 20% [p < .01]; group 2: 33% [p < .01]), and D over dot O-2 (group 1: 19% [p < .01]; group 2: 27% [p < .01]). However, V over dot O-2, whether directly measured from the respiratory gases or calculated by the cardiovascular Fick principle, did not change in both groups with dopamine, while the oxygen extraction ratio decreased significantly in both groups with dopamine. Heart rate, pulmonary artery occlusion pressure, and pulmonary shunt fraction all increased with dopamine, Pao(2) decreased, but oxygen saturation remained stable in both groups with dopamine. Conclusions: Short-term dopamine infusion in hyperdynamic septic shock patients, de. spite producing higher global D over dot O-2, was not superior to dobutamine or the combination of dobutamine and norepinephrine infusion.
Hannemann L; Reinhart K; Grenzer O; Meierhellmann A; Bredle D L
Critical Care Medicine
1995
1995-12
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1097/00003246-199512000-00004" target="_blank" rel="noreferrer noopener">10.1097/00003246-199512000-00004</a>
Dissociation of diabetes and obesity in mice lacking orphan nuclear receptor small heterodimer partner
beta-oxidation; Biochemistry & Molecular Biology; birth-weight; diet-induced obesity; fatty-acid oxidation; hepatic steatosis; induced; insulin sensitivity; insulin-resistance; lipid-metabolism; liver; negative feedback-regulation; oxygen consumption; quotient; respiratory; retinoic acid; signaling pathways; skeletal-muscle
Mixed background SHP(-/-) mice are resistant to diet-induced obesity due to increased energy expenditure caused by enhanced PGC-1 alpha expression in brown adipocytes. However, congenic SHP(-/-) mice on the C57BL/6 background showed normal expression of PGC-1 alpha and other genes involved in brown adipose tissue thermogenesis. Thus, we reinvestigated the impact of small heterodimer partner (SHP) deletion on diet-induced obesity and insulin resistance using congenic SHP(-/-) mice. Compared with their C57BL/6 wild-type counterparts, SHP(-/-) mice subjected to a 6 month challenge with a Western diet (WestD) were leaner but more glucose intolerant, showed hepatic insulin resistance despite decreased triglyceride accumulation and increased beta-oxidation, exhibited alterations in peripheral tissue uptake of dietary lipids, maintained a higher respiratory quotient, which did not decrease even after WestD feeding, and displayed islet dysfunction. Hepatic mRNA expression analysis revealed that many genes expressed higher in SHP(-/-) mice fed WestD were direct peroxisome proliferator-activated receptor alpha (PPAR alpha) targets. Indeed, transient transfection and chromatin immunoprecipitation verified that SHP strongly repressed PPAR alpha-mediated transactivation. SHP is a pivotal metabolic sensor controlling lipid homeostasis in response to an energy-laden diet through regulating PPAR alpha-mediated transactivation. The resultant hepatic fatty acid oxidation enhancement and dietary fat redistribution protect the mice from diet-induced obesity and hepatic steatosis but accelerate development of type 2 diabetes.-Park, Y. J., S. C. Kim, J. Kim, S. Anakk, J. M. Lee, H-T. Tseng, V. Yechoor, J. Park, J-S. Choi, H. C. Jang, K-U. Lee, C. M. Novak, D. D. Moore, and Y. K. Lee. Dissociation of diabetes and obesity in mice lacking orphan nuclear receptor small heterodimer partner. J. Lipid Res. 2011. 52: 2234-2244.
Park Y J; Kim S C; Kim J; Anakk S; Lee J M; Tseng H T; Yechoor V; Park J; Choi J S; Jang H C; Lee K U; Novak C M; Moore D D; Lee Y K
Journal of Lipid Research
2011
2011-12
Journal Article
<a href="http://doi.org/10.1194/jlr.M016048" target="_blank" rel="noreferrer noopener">10.1194/jlr.M016048</a>
Expression Of Type-specific Mhc Isoforms In Rat Intrafusal Muscle-fibers
cat; Cell Biology; differentiation; fiber types; histochemistry; identification; immunocytochemistry; innervation; intrafusal; monoclonal antimyosin antibodies; monoclonal-antibody; motor; muscle fiber typing; muscle spindles; myosin heavy-chain; rat skeletal muscle; skeletal-muscle; spindles
Myosin heavy chain (MHC) expression by intrafusal fibers was studied by immunocytochemistry to determine how closely it parallels MHC expression by extrafusal fibers in the soleus and tibialis anterior muscles of the rat. Among the MHC isoforms expressed in extrafusal fibers, only the slow-twitch MHC of Type 1 extrafusal fibers was expressed along much of the fibers. Monoclonal antibodies (MAb) specific for this MHC bound to the entire length of bag2 fibers and the extracapsular region of bag1 fibers. The fast-twitch MHC isoform strongly expressed by bag2 and chain fibers had an epitope not recognized by MAb to the MHC isoforms characteristic of developing muscle fibers or the three subtypes (2A, 2B, 2X) of Type 2 extrafusal fibers. Therefore, intrafusal fibers may express a fast-twitch MHC that is not expressed by extrafusal fibers. Unlike extrafusal fibers, all three intrafusal fiber types bound MAb generated against mammalian heart and chicken limb muscles. The similarity of the fast-twitch MHC of bag2 and chain fibers and the slow-tonic MHC of bag1 and bag2 fibers to the MHC isoforms expressed in avian extrafusal fibers suggests that phylogenetically primitive MHCs might persist in intrafusal fibers. Data are discussed relative to the origin and regional regulation of MHC isoforms in intrafusal and extrafusal fibers of rat hindlimb muscles.
Kucera J; Walro J M; Gorza L
Journal of Histochemistry & Cytochemistry
1992
1992-02
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1177/40.2.1552171" target="_blank" rel="noreferrer noopener">10.1177/40.2.1552171</a>
INFLUENCE OF N-ACETYLCYSTEINE ON INDIRECT INDICATORS OF TISSUE OXYGENATION IN SEPTIC SHOCK PATIENTS - RESULTS FROM A PROSPECTIVE, RANDOMIZED, DOUBLE-BLIND-STUDY
blood gas analysis; critical illness; critically-ill patients; endotoxin; gastric mucosa; General & Internal Medicine; glutathione; intramural ph; l-arginine; multiple organ failure; n-acetylcysteine; nitric-oxide synthesis; organ failure; oxygen consumption; ph; relaxing factor; sepsis; septic; shock; skeletal-muscle; tissue oxygenation
Objectives: Deactivation of endothelium-derived relaxing factor due to an increased oxygen radical load during sepsis may contribute to an impairment in microcirculatory blood flow. We investigated whether treatment with the sulfhydryl donor and oxygen radical scavenger, N-acetylcysteine, would improve whole-body oxygen consumption (Vo(2)), gastric intramucosal pH, and veno-arterial CO2 gradient (veno-arterial PCO2) during septic shock. Design: Prospective, randomized, double-blind study conducted over 2 yrs. Setting: Septic shock patients admitted to the intensive care unit. Patients: Fifty-eight patients requiring hemodynamic monitoring (radial and pulmonary artery catheters) due to septic shock, were included in this study. All patients were examined within 72 hrs after the onset of sepsis. They were optimally resuscitated by conventional means with volume and inotropic agents, and exhibited stable clinical conditions (hemodynamic values, body temperature, hemoglobin, FIO2). Interventions: A gastric tonometer was inserted to measure the gastric intramucosal pH. Subjects randomly received either 150 mg/kg of intravenous N-acetylcysteine or placebo over a 15-min period, then a continuous infusion of 12.5 mg/hr of N-acetylcysteine or placebo over similar to 90 mins. Measurements: Infusion measurements were begun 60 mins after the beginning of infusion and lasted similar to 30 mins. The infusion was then discontinued and 2 hrs later the final measurements were taken. Main Results: Basic patient characteristics (age, sex, Acute Physiology and Chronic Health Evaluation [APACHE] II scores, Multiple Organ Failure scores) did not differ significantly, nor did pre- and 2-hr postinfusion measurements differ between any of the groups. Thirteen (45%) patients responded (i.e., showed an increase in Vo(2) >10%, reaching a mean of 19%) to the N-acetylcysteine infusion. The N-acetylcysteine responders also showed an increase in gastric intramucosal pH, a decrease in veno-arterial PCO2, an increase in oxygen delivery, cardiac index, stroke index, and left ventricular stroke work index, as well as a significant decrease in systemic vascular resistance in comparison to baseline. The N-acetylcysteine nonresponders, as well as the patients in the placebo group, did not show any significant changes in any of these variables. The N-acetylcysteine responders had a higher survival rate (69%) than the nonresponders (19%) and were studied earlier after onset of sepsis (37 hrs) than the nonresponders (61 hrs). The only significant difference between the entire N-acetylcysteine group (which included responders plus nonresponders) and the placebo group was an increased 30, in the entire N-acetylcysteine group during infusion measurements. Conclusions: N-acetylcysteine provided a transient improvement in tissue oxygenation in about half of the septic shock patients, as indicated by an increase in Vo(2) and gastric intramucosal pH and a decrease in veno-arterial PCO2. The higher survival rate in the N-acetylcysteine responders and the fact that half of the patients receiving N-acetylcysteine did not respond, suggests that, in some patients, sepsis irreversibly damages the microvasculature to the extent that N-acetylcysteine has no effect. If analyzed by intention to treat, the N-acetylcysteine did not produce effects that were significantly different from the placebo. Whether the N-acetylcysteine challenge was merely diagnostic or whether N-acetylcysteine can be effective in the treatment of sepsis deserves further investigation.
Spies C D; Reinhart K; Witt I; Meierhellmann A; Hannemann L; Bredle D L; Schaffartzik W
Critical Care Medicine
1994
1994-11
Journal Article
n/a
Jaw-muscle fiber architecture in tufted capuchins favors generating relatively large muscle forces without compromising jaw gape
Anthropology; Cebus; cross-sectional area; dental microwear; Early; enamel thickness; Evolutionary Biology; feeding-behavior; Fiber length; genus cebus; hominin diet; mandibular morphology; masseter; masseter muscle; maximal bite force; myofibrillar atpase activity; PCSA; sarcomere-length; skeletal-muscle; Temporalis
Tufted capuchins (sensu lato) are renowned for their dietary flexibility and capacity to exploit hard and tough objects. Cebus apella differs from other capuchins in displaying a suite of craniodental features that have been functionally and adaptively linked to their feeding behavior, particularly the generation and dissipation of relatively large jaw forces. We compared fiber architecture of the masseter and temporalis muscles between C. apella (n = 12) and two "untufted" capuchins (C. capucinus, n = 3; C. albifrons, n = 5). These three species share broadly similar diets, but tufted capuchins occasionally exploit mechanically challenging tissues. We tested the hypothesis that tufted capuchins exhibit architectural properties of their jaw muscles that facilitate relatively large forces including relatively greater physiologic cross-sectional areas (PCSA), more pinnate fibers, and lower ratios of mass to tetanic tension (Mass/P-0). Results show some evidence supporting these predictions, as C. apella has relatively greater superficial masseter and temporalis PCSAs, significantly so only for the temporalis following Bonferroni adjustment. Capuchins did not differ in pinnation angle or Mass/P-0. As an architectural trade-off between maximizing muscle force and muscle excursion/contraction velocity, we also tested the hypothesis that C. apella exhibits relatively shorter muscle fibers. Contrary to our prediction, there are no significant differences in relative fiber lengths between tufted and untufted capuchins. Therefore, we attribute the relatively greater PCSAs in tufted capuchins primarily to their larger muscle masses. These findings suggest that relatively large jaw-muscle PCSAs can be added to the suite of masticatory features that have been functionally linked to the exploitation of a more resistant diet by C. apella. By enlarging jaw-muscle mass to increase PCSA, rather than reducing fiber lengths and increasing pinnation, tufted capuchins appear to have increased jaw-muscle and bite forces without markedly compromising muscle excursion and contraction velocity. One performance advantage of this morphology is that it promotes relatively large bite forces at wide jaw gapes, which may be useful for processing large food items along the posterior dentition. We further hypothesize that this morphological pattern may have the ecological benefit of facilitating the dietary diversity seen in tufted capuchins. Lastly, the observed feeding on large objects, coupled with a jaw-muscle architecture that facilitates this behavior, raises concerns about utilizing C. apella as an extant behavioral model for hominins that might have specialized on small objects in their diets. (C) 2009 Elsevier Ltd. All rights reserved.
Taylor A B; Vinyard C J
Journal of Human Evolution
2009
2009-12
Journal Article
<a href="http://doi.org/10.1016/j.jhevol.2009.06.001" target="_blank" rel="noreferrer noopener">10.1016/j.jhevol.2009.06.001</a>
N-ACETYLCYSTEINE PRESERVES OXYGEN-CONSUMPTION AND GASTRIC-MUCOSAL PH DURING HYPEROXIC VENTILATION
cardiac-output; critically-ill patients; endotoxin; gas-exchange; General & Internal Medicine; l-arginine; nitric-oxide synthesis; relaxing factor; Respiratory System; septic patients; skeletal-muscle; superoxide
Hyperoxic ventilation, used to prevent hypoxemia during potential periods of hypoventilation, has been reported to paradoxically decrease whole body oxygen consumption (Vo(2)). Reduction in nutritive blood flow due to oxygen radical production is one possible mechanism. We investigated whether pretreatment with the sulfhydryl group donor and O-2 radical scavenger N-acetylcysteine (NAG) would preserve whole body Vo(2) and prevent deterioration of oxygenation in gastric mucosal tissue during hyperoxia. Thirty-eight patients, requiring hemodynamic monitoring (radial and pulmonary artery catheters) due to sepsis syndrome, were included in this randomized experiment. All patients exhibited stable clinical conditions (hemodynamics, body temperature, hemoglobin, Flo(2) < 0.5). A gastric tonometer was placed to measure the gastric intramucosal pH (pH(i)), which indirectly assesses nutritive blood flow to the mucosa. Cardiac output was determined by thermodilution and Vo(2) by cardiovascular Fick. After baseline measurements, patients randomly received either 150 mg . kg(-1) NAC (n = 19) or placebo (n = 19) in 250 ml 5% dextrose intravenously over a period of 15 min. Measurements were repeated 30 min after starting NAC or placebo infusion, 30 min after starting hyperoxia (Flo(2) = 1.0), and 60 min after resetting the original Flo(2). There were no significant differences between groups in any of the measurements before treatment and after the return to baseline Flo(2) at the end of the study. NAG, but not placebo infusion, caused a slight but significant increase in cardiac output and decrease in systemic vascular resistance. Significant differences between groups during hyperoxia were: Vo(2) (NAG: 114 +/- 9 mi min(-1) m(-2) versus placebo: 81 +/- 31 ml . min(-1) m(-2); p = 0.008) and oxygen extraction ratio (NAG: 21 +/- 6% versus placebo: 14 +/- 5%; p = 0.003). The mean decrease of Vo(2) was 11% in the NAC group versus 34% in the placebo group. The mean decrease of the oxygen extraction ratio was 12% in the NAC group versus 34% in the placebo group. NAC prevented a decrease in pH(i) in hyperoxia (NAG: 7.28 +/- 0.10 versus placebo: 7.14 +/- 0.18; p = 0.012). NAC helped preserve whole body oxygen uptake, oxygen extraction ratio, and pH(i) during brief hyperoxia in these septic patients. This suggests that pretreatment with NAC can attenuate impaired tissue oxygenation during hyperoxia.
Reinhart K; Spies C D; Meierhellmann A; Bredle D L; Hannemann L; Specht M; Schaffartzik W
American Journal of Respiratory and Critical Care Medicine
1995
1995-03
Journal Article
n/a
Relationships between NADPH diaphorase staining and neuronal, endothelial, and inducible nitric oxide synthase and cytochrome P450 reductase immunoreactivities in guinea-pig tissues
brain; Cell Biology; cells; expression; histochemical-localization; in-situ hybridization; Microscopy; no synthase; pig intestine; rat; signal-transduction; skeletal-muscle
The presence of NADPH diaphorase staining was compared with the immunohistochemical localization of four NADPH-dependent enzymes - neuronal (type I), inducible (type LI), and endothelial (type III) nitric oxide synthase (NOS) and cytochrome P450 reductase. Cell types that were immunoreactive for the NADPH-dependent enzymes were also stained for NADPH diaphorase, suggesting that endothelial and neuronal NOS and cytochrome P450 reductase all show NADPH diaphorase activity in formaldehyde-fixed tissue. However, in some tissues, the presence of NADPH diaphorase staining did not coincide with the presence of any of the NADPH-dependent enzymes we examined. In Vascular endothelial cells, the punctate pattern of staining observed with NADPH diaphorase histochemistry was identical to that seen following immunohistochemistry using antibodies to endothelial NOS. In enteric and pancreatic neurons and in skeletal muscle, the presence of NADPH diaphorase staining correlated with the presence of neuronal NOS. In the liver, sebaceous glands of the skin, ciliated epithelium, and a subpopulation of the cells in the subserosal glands of the trachea, zona glomerulosa of the adrenal cortex, and epithelial cells of the lacrimal and salivary glands, the presence of NADPH diaphorase staining coincided with the presence of cytochrome P450 reductase immunoreactivity. In epithelial cells of the renal tubules and zona fasciculata and zona reticularis of the adrenal cortex, NADPH diaphorase staining was observed that did not coincide with the presence of any of the enzymes. Inducible NOS was not observed in any tissue. Thus, while tissues that demonstrate immunoreactivity for neuronal and endothelial NOS also stain positively for NADPH diaphorase activity, the presence of NADPH diaphorase staining does not reliably or specifically indicate the presence of one or more NOS isoforms.
Young H M; Obrien A J; Furness J B; Ciampoli D; Hardwick J P; McCabe T J; Narayanasami R; Masters B S S; Tracey W R
Histochemistry and Cell Biology
1997
1997-01
Journal Article
<a href="http://doi.org/10.1007/s004180050085" target="_blank" rel="noreferrer noopener">10.1007/s004180050085</a>
Sequences Of Intrafusal Fiber Formation Are Muscle-dependent In Rat Hindlimbs
Anatomy & Morphology; cat; development; Developmental Biology; embryonic-development; expression; innervation; intrafusal fibers; motor; muscle; muscle spindles; myosin heavy chains; myosin heavy-chain; neonatal rats; skeletal-muscle; slow myosin; spindles; tenuissimus muscles
A rat muscle spindle typically contains four intrafusal fibers - one nuclear bag(2), one nuclear bag, and two nuclear chain fibers. We compared the sequence of formation of the three intrafusal fiber types among the tibialis anterior (TA), soleus (SOL) and medial gastrocnemius (RIG) muscles using immunocytochemistry of spindle-specific myosin heavy chain isoforms. Spindles of the TA began to differentiate earlier and acquired the full complement of intrafusal fibers sooner than spindles of the SOL or MG muscles. At the onset of spindle assembly, the intrafusal myotubes expressed myosin heavy chains similar to those expressed by extrafusal myotubes. The first intrafusal myotube then differentiated into the bag, fiber regardless of the muscle. However, the fate of the second-forming intrafusal myotube varied among the muscles studied. It usually differentiated into a chain fiber in the TA, into a bag(1) fiber in the SOL, and into either a bag(1) or a chain in the MG. The fate of the third-forminge was reciprocal to that of the second; i.e. in those spindles in which the bag(1) fiber was second to form, a chain was third, and vice versa. The fourth and last intrafusal myotube gave rise to a chain fiber. The inter- and intramuscular variability in the fate of intrafusal myotubes of the second and third generation argues against the existence of a program intrinsic to the myotubes that would mandate their differentiation along specific paths. Rather, an extrinsic regulatory factor, probably associated with the primary afferent neuron, may govern differentiation of pluripotential myotubes into particular types of intrafusal fiber. The fate of the intrafusal myotubes might then depend on the timing of the regulatory effect of afferents relative to the stage of development of the intrafusal bundle.
Kucera J; Walro J M
Anatomy and Embryology
1994
1994-09
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1007/bf00234305" target="_blank" rel="noreferrer noopener">10.1007/bf00234305</a>
The additive effects of carnitine and ascorbic acid on distally burned dorsal skin flap in rats
ischemia; prevention; ultrastructure; Research & Experimental Medicine; model; metabolism; skeletal-muscle; vitamin C; burn; carnitine; skin flap; thermal-injury
Background: The purpose of this study was to determine the effects of combined use of L-carnitine and vitamin C on partially burned skin flap in an experimental rat model. Material/Methods: In the rat dorsal skin, a 10x3 cm flap was marked. The most distal 3x3 cm part was burned to full thickness. Twenty-four rats were randomized into four groups with 6 animals in each. Group 1 was simply followed tip. Group 2 was given 0.5 mg/kg vitamin C per day for 7 days, group 3 100 mg/kg carnitine per day for 7 days, and group 4 both carnitine and vitamin C. On the eighth postoperative day, the animals were sacrificed and examined. The surviving and necrotic areas were determined by macroscopic examination and measured with a planimeter. Results: The areas of flap necrosis were measured. The median surviving areas and areas of flap necrosis, respectively, of the groups were: group 1, 16.0 cm(2) and 14.0 cm(2); group 2, 18.25 cm(2) and 11.75 cm(2); group 3, 20.0 cm(2) and 10 cm(2); and group 4, 23.75 cm(2) and 6.25 cm(2). The surviving areas of the groups were found to be significantly different (p=0.000).
Arslan E; Basterzi Y; Aksoy A; Majka C; Unal S; Sari A; Demirkan F
Medical Science Monitor
2005
2005-06
Journal Article or Conference Abstract Publication
n/a
The Functional Correlates of Jaw-Muscle Fiber Architecture in Tree-Gouging and Nongouging Callitrichid Monkeys
Anthropology; arboreal guenons; bite force; callitrichids; cross-sectional area; Evolutionary Biology; Exudativory; Fiber length; gape; internal architecture; jaw; marmosets; masseter muscle; morphology; physiologic cross-sectional area; rabbit oryctolagus-cuniculus; sarcomere-length; skeletal-muscle; tamarins; temporalis muscle; world monkeys
Common (Callithrix jacchus) and pygmy (Cebuella pygmaea) marmosets and cotton-top tamarins (Saguinus oedipus) share broadly similar diets of fruits, insects, and tree exudates. Marmosets, however, differ from tamarins in actively gouging trees with their anterior dentition to elicit tree exudates flow. Tree gouging in common marmosets involves the generation of relatively wide jaw gapes, but not necessarily relatively large bite forces. We compared fiber architecture of the masseter and temporalis muscles in C. jacchus (N = 18), C. pygmaea (N = 5), and S. oedipus (N = 13). We tested the hypothesis that tree-gouging marmosets would exhibit relatively longer fibers and other architectural variables that facilitate muscle stretch, As an architectural trade-off between maximizing muscle excursion/contraction velocity and muscle force, we also tested the hypothesis that marmosets would exhibit relatively less pinnate fibers, smaller physiologic cross-sectional areas (PCSA), and lower priority indices (I) for force. As predicted, marmosets display relatively longer-fibered muscles, a higher ratio of fiber length to muscle mass, and a relatively greater potential excursion of the distal tendon attachments, all of which favor muscle stretch. Marmosets further display relatively smaller PCSAs and other features that reflect a reduced capacity for force generation. The longer fibers and attendant higher contraction velocities likely facilitate the production of relatively wide jaw gapes and the capacity to generate more power from their jaw muscles during gouging. The observed functional trade-off between muscle excursion/contraction velocity and muscle force suggests that primate jaw-muscle architecture reflects evolutionary changes related to jaw movements as one of a number of functional demands imposed on the masticatory apparatus. Am J Phys Anthropol 139:353-367, 2009. (C) 2009 Wiley-Liss, Inc.
Taylor A B; Eng C M; Anapol F C; Vinyard C J
American Journal of Physical Anthropology
2009
2009-07
Journal Article
<a href="http://doi.org/10.1002/ajpa.20991" target="_blank" rel="noreferrer noopener">10.1002/ajpa.20991</a>
The Morphology Of The Masticatory Apparatus Facilitates Muscle Force Production At Wide Jaw Gapes In Tree-gouging Common Marmosets (callithrix Jacchus)
3-dimensional mathematical-model; bite forces; biting; common marmosets; cross-sectional area; efficiency; fiber architecture; fiber length; jaw gape; Life Sciences & Biomedicine - Other Topics; masseter; masseter muscle; masticatory mechanics; muscle architecture; opening index; physiological; range; rhesus-monkey; sarcomere length operating; sarcomere-length; skeletal-muscle; superficial masseter; temporalis; tree gouging
Eng C M; Ward S R; Vinyard C J; Taylor A B
Journal of Experimental Biology
2009
2009-12
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1242/jeb.029983" target="_blank" rel="noreferrer noopener">10.1242/jeb.029983</a>
Transient Expression Of A Slow-tonic Mhc Isoform By Extrafusal Fibers In The Developing Rat
Anatomy & Morphology; denervation; Developmental Biology; diversity; extrafusal fibers; intrafusal fibers; intrafusal muscle-fibers; monoclonal-antibody; motor innervation; muscle; myosin heavy-chain; neonatal rats; skeletal-muscle; slow-tonic myosin; spindles
ALD 19, a monoclonal antibody that recognizes the slow-tonic myosin heavy chain (MHC) isoform, has been used extensively as a marker for nuclear bag intrafusal fibers of muscle spindles in developing and adult rats. Extrafusal fibers of adult rat hindlimb muscles do not express slow-tonic MHC. However, while using ALD 19 to trace the fate of intrafusal fibers following neonatal denervation, we noted that some extrafusal fibers of neonates also bound this antibody. The immunolabeled extrafusal fibers were a subset of slow fibers located in the deep axial regions of crural muscles. The same fiber subset transiently displayed a weak affinity for ALD 19 during the first postnatal week in normal muscles. Denervation at birth increased the intensity of ALD 19 immunolabelling by these extrafusal fibers and extended the duration of the slow-tonic immunoreactivity into the 2nd postnatal week, after which expression diminished or ceased. Demonstration that some developing extrafusal fibers have a nerve-independent capacity for transiently expressing slow-tonic MHC, an MHC previously thought to be expressed only by intrafusal fibers, raises the possibility that both types of fiber originate from a subset of bipotential slow primary myotubes in rat hindlimbs.
Kucera J; Walro J M
Anatomy and Embryology
1993
1993-10
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1007/bf00185950" target="_blank" rel="noreferrer noopener">10.1007/bf00185950</a>
Vascular Endothelial Growth Factor and the Collateral Circulation The Story Continues
angiogenesis; arteriogenesis; receptors; cells; Cardiovascular System & Cardiology; expression; Hematology; skeletal-muscle; permeability factor; vasculogenesis; vasculotropin; vegf family-members
Chilian W M; Pung Y F
Circulation Research
2008
2008-10
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1161/01.RES.0000338258.90706.2c" target="_blank" rel="noreferrer noopener">10.1161/01.RES.0000338258.90706.2c</a>