Fisiología del ejercicio en la práctica de la vocología colombiana: una necesidad / Exercise physiology in Colombian vocology practice: a necessity

En los últimos años, la vocología ha prestado un interés particular a la investigación y aplicación clínica de principios ­basados en la ciencia­ que permitan maximizar el aprendizaje y el control motor asociados al funcionamiento de la voz. El proceso de producción vocal ocurre gracias a la acción coordinada de los subsistemas de respiración, fonación y resonancia. Estos, a su vez, deben su operatividad a la activación de diversos músculos que parecen comportarse de forma similar a aquellos que componen las extremidades. Teniendo esto en cuenta, los principios del ejercicio que han demostrado efectividad para mejorar la fuerza y resistencia de la musculatura de las extremidades podrían aplicarse al entrenamiento de la voz. En primer lugar, en este documento se presentan algunos aspectos funcionales del tejido muscular, describiendo las fibras musculares tipo I y II y puntualizando en la distribución de dichas fibras en la musculatura que hace parte de los subsistemas de la función vocal. En segundo lugar, se exponen las adaptaciones fisiológicas derivadas del ejercicio (acondiciona-miento) así como de la degeneración propia de la inactividad (desacondicionamiento). Posteriormente, se hace una explicación del enfoque de ejercitación de resistencia progresiva junto a los cinco principios que lo definen, concentrada en su aplicación a la vocología. Finalmente, se argumenta la necesidad de incluir la ciencia del ejercicio en la práctica e investigación en vocología en el contexto colombiano a la luz de algunos reportes nacionales disponibles hasta la fecha.

In recent years, vocology has focused especially in research and clinical application of evidence-based principles that enhance motor learning and motor control related to voice function. The process of voice production occurs due to coordinated action of respiration, phonation and resonance subsystems. Likewise, the function of these subsystems is a result of the activation of a variety of muscles that seem to behave similarly to skeletal limb muscles. Taking this into account, exercise principles that improve strength and endurance of skeletal limb muscles may also be applied to im-prove performance of voice production. First, this article focuses on functional aspects of muscle tissue; muscle fiber types I and II are described and, in the same way, the distribution of these fibers in voice production muscles is pointed out. Second, phy-siological adaptations to training (conditioning) as well as detraining from inactivity (deconditioning) are portrayed. Afterwards, progressive resistance training is explai-ned next to its principles and its application to vocology. Finally, the paper argues the necessity of including exercise science into practice and research of vocology in Colombian context, based on some national reports available to date

Morphological classification and comparison of suboccipital muscle fiber characteristics / 대한해부학회지

In an attempt to clarify the function of the suboccipital muscles, we performed morphological observation of the suboccipital muscles for variations in the muscle belly and compared the morphology of their muscle fibers in terms of cross-sectional area by immunostaining with anti-myosin heavy chain antibodies. The cadavers of 25 Japanese individuals were used: 22 for morphological examinations and three for histological examinations. Among samples of the rectus capitis posterior major muscle (RCPma) and rectus capitis posterior minor muscle (RCPmi), 86.4% had a typical muscle appearance with a single belly, and 13.6% had an anomalous morphology. None of the samples of the obliquus capitis superior (OCS) or obliquus capitis inferior (OCI) muscles had an anomalous appearance. Measurement of cross-sectional area revealed that fast-twitch muscle fibers in the RCPma and OCI had a significantly greater cross-sectional area than those of the RCPmi and OCS. The cross-sectional area of intermediate muscle fibers was also significantly greater in the OCS than in the RCPma, RCPmi, and OCI. The cross-sectional area of slow-twitch muscle fibers was significantly greater in the OCS than in the RCPma, RCPmi, and OCI, and the RCPmi showed a significantly greater cross-sectional area for slow-twitch muscle fibers than did the RCPma, and OCI. Our findings indicate that the RCPmi and OCS exert a greater force than the RCPma and OCI, and act as anti-gravity agonist muscles of the head. Prolonged head extension in individuals with anomalous suboccipital muscle groups could result in dysfunction due to undue stress.

Histochemistry profile of the biceps brachii muscle fibres of capuchin monkeys (Cebus apella, Linnaeus, 1758) / Perfil histoquímico das fibras do músculo bíceps braquial do macaco-prego (Cebus apella, Linnaeus, 1758)

A general analysis of the behaviour of “Cebus” shows that when this primate moves position to feed or perform another activity, it presents different ways of locomotion. This information shows that the brachial biceps muscle of this animal is frequently used in their locomotion activities, but it should also be remembered that this muscle is also used for other development activities like hiding, searching for objects, searching out in the woods, and digging in the soil. Considering the above, it was decided to research the histoenzimologic characteristics of the brachial biceps muscle to observe whether it is better adpted to postural or phasic function. To that end, samples were taken from the superficial and deep regions, the inserts proximal (medial and lateral) and distal brachial biceps six capuchin monkeys male and adult, which were subjected to the reactions of m-ATPase, NADH-Tr. Based on the results of these reactions fibres were classified as in Fast Twitch Glycolitic (FG), Fast Twitch Oxidative Glycolitic (FOG) and Slow Twitc (SO). In general, the results, considering the muscle as a whole, show a trend of frequency FOG> FG> SO. The data on the frequency were studied on three superficial regions FOG=FG>SO; the deep regions of the inserts proximal FOG=FG=SO and inserting the distal FOG>FG=SO. In conclusion, the biceps brachii of the capuchin monkey is well adapted for both postural and phasic activities.

Uma análise geral do comportamento do “Cebus apella” mostra que este primata quando desloca para se alimentar ou realizar outra atividade apresenta diferentes maneiras de locomoção. Estas informações mostram que o músculo bíceps braquial deste animal é usado freqüentemente nas suas atividades de locomoção, mas deve ser lembrado ainda que este músculo é usado também para desenvolvimento de outras atividades como esconder-se, procurar objetos, vasculhar arboredos, além de cavar o chão. Considerando-se o exposto acima decidiu-se pesquisar as características histoenzimológicas do músculo bíceps braquial do macaco-prego com o objetivo de comparar se este músculo esta melhor adaptado para funções posturais ou fásicas. As amostras foram retiradas das regiões superficiais e profundas; inserções proximais (medial e lateral) e distal de seis macacos-prego machos e adultos, os quais foram submetidos às reações de m-ATPase, NADH-Tr. Baseado nos resultados das reações, as fibras foram classificadas em Fast Twitch Glycolitic (FG), Fast Twitch Oxidative Glycolitic (FOG) e Slow Twitch (SO). Quanto à área dos diferentes tipos de fibras, os resultados encontrados foram semelhantes em todas as amostras estudadas, e as fibras de contração rápida foram sempre maiores do que as de contração lenta (FG=FOG>SO). Os dados obtidos sobre a frequência foram: nas três regiões superficiais estudadas FOG=FG>SO; nas regiões profundas das inserções proximais FOG=FG=SO e na inserção distal FOG>FG=SO. Baseado nestes dados pode-se concluir que o músculo bíceps braquial do macaco-prego está bem adaptado tanto para atividades posturais como fásicas.

Regime alimentar para ganho compensatório de ovinos em confinamento: composição regional e tecidual da carcaça / Diet for compensatory gain of feedlot lambs: commercial composition of carcass cuts and tissues

Determinou-se o efeito do regime alimentar para ganho compensatório sobre a composição regional e tecidual da carcaça de cordeiros terminados em confinamento. Foram utilizados 40 ovinos Santa Inês, machos, com média de 17±1,7kg de peso vivo (PV) e 100 dias de idade. Ao final do período de confinamento, os cordeiros foram abatidos, e a meia carcaça esquerda foi seccionada em cinco cortes comerciais primários: pescoço, paleta, costilhar, lombo e perna. A perna foi dissecada em músculos, ossos e gorduras, e, em seguida, teve seu índice de musculosidade determinado. Foi mensurada a hipertrofia muscular por meio da média do diâmetro das fibras musculares. O peso (g) da meia carcaça esquerda, do pescoço, da paleta, do costilhar, do lombo e da perna diminuiu linearmente, à medida que aumentou o nível de restrição prévia, de 0% até 60%, variando, respectivamente, de 11497,4 a 8888,5; de 1453,8 a 1211,4; de 1955,4 a 1560,9; de 3420,0 a 2604,6; de 1669,4 a 1161,6 e de 2998,8 a 2350,0. No rendimento dos cortes, apenas o lombo sofreu efeito do regime alimentar, diminuindo de 14,5 para 13,1%. O índice de musculosidade da perna (0,42 a 0,39) e o diâmetro das fibras musculares (46,0 a 43,4µm) também diminuíram com o aumento da restrição prévia. A restrição alimentar seguida por realimentação diminui o peso dos cortes e não afeta seu rendimento; diminui também a proporção de gordura da carcaça, produzindo, assim, cortes mais leves e carne com menor teor de gordura.

The effect of diets for compensatory gain on the commercial cut yield and carcasses tissue composition of finished feedlot lambs was determined. A total of 40 Santa Inês lambs, with mean body weight (BW) of 17±1.7kg and 100 days old were used. The lambs were slaughtered; the left half carcass was sectioned into five primary commercial cuts: neck, shoulder, rib, loin and leg. The leg was dissected into muscle, bone and fat, and then the muscularity of the leg was determined. Muscle hypertrophy was measured by the mean diameter of muscle fibers. The left half carcass, neck, shoulder, rib, loin and leg weight decreased linearly between 0 and 60% of previous food restriction levels, ranging, respectively, from 11497.4 to 8888.5g; from 1453.8 to 1211.4g; from 1955.4 to 1560.9g; from 3420.0 to 2604.6g; from 1669.4 to 1161.6g and from 2998.8 to 2350.0g, as well as loin yield (from 14.5 to 13.1%), leg musculosity index (from 0.42 to 0,39) and muscle fiber diameter (from 46.0 to 43.4µm). Food restriction followed by refeeding promoted decreasing in the weight of cuts and did not affect the yield, and it also decreased the proportion of fat in the carcass, resulting in lighter cuts and leaner meat.

The relationship between contractile characteristics and fiber type conversion in hind-limb unloading mice soleus / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To explore the relationship between contractile characteristics and fiber type conversion in hind-limb unloading mice soleus.</p><p><b>METHODS</b>After 28-day hind-limb unloading and muscle atrophy, we used the method of isolated muscle perfusion with different stimulated protocols to determine the changes in contractile characteristics including the isometric twitch force and tetanus force and fatigue index of slow twitch muscle in mice. The muscle myofibrillar composition and fiber type conversion were detected by immunofluorescence staining and real-time PCR.</p><p><b>RESULTS</b>The isometric twitch force and the tetanus force and fatigue index were decreased progressively in 28-day unloaded mice soleus, with the increase in fast twitch fiber subtype and the decrease in slow twitch fiber subtype.</p><p><b>CONCLUSION</b>The alteration of contractile characteristics is relevant to the slow-to-fast fiber conversion in mice soleus after 28-day hind-limb unloading.</p>

[ effect of resistance training on plasma and skeletal muscles sphingosine-1-phosphate levels of male Wistar rat]

Sphingosine 1-phosphate [S1P] is a bioactive platelet-derived sphingolipid that is involved in regulation of proliferation, differentiation, hypertrophy and anti-apoptosis of cells and activation of satellite cells. The purpose of present study was to examine the effect of resistance training on S1P levels of plasma and skeletal muscles in male Wistar rats. Twenty four 8-week-old male Wistar rats were used in this study. The initial body weight of rats was 190 to 250 gr. All animals were maintained in pairs in an environmentally controlled room at 22°C, 12:12-h photoperiod cycle and allowed normal cage activity. The animals were fed standard rat chow and water ad libitum. After a week of acclimation to the animal facility, the rats were assigned randomly to a control [N=12] or training [N=12] group. Resistance training was done using a 1 meter height ladder with 2 cm grid with an 85 degree incline, and weights attached to rat's tails. The content of sphingosine-1- phosphate [S1P] present in the chloroform layer was determined by means of high performance liquid chromatography [HPLC]. Resistance exercise training increased the total content of S1P in FHL [fast-twitch] [P=0.003] and soleus [slow-twitch] [P=0.008] muscles and plasma [P=0.001] in comparison with control group. It is concluded that resistance exercise training strongly affects the S1P content in fast and slow twitch muscles and plasma

Histochemistry and morphometric analysis of muscle fibers from patients with duchenne muscular dystrophy (DMD) / Histoquímica y análisis morfométrico de las fibras musculares de p0acientes con distrofia muscular de duchenne (DMD)

The aim of the study was to analyze the muscle fibers by histochemistry and morphometric methods from patients with Duchenne muscular dystrophy (DMD). Muscle biopsies were taken from the vastus lateralis muscle of five boys between 13 and 15-years of age, with clinical diagnosis of DMD. The histochemistry was performed using myofibrillar ATPases (9.6, 4.6 and 4.3). To morphometrical analysis a computerized semiautomatic system and software Image-Lab was used. ATPase staining showed atrophy of muscle fibers. Fibrosis and adipose deposition occurred in variable degree depending of muscular involvement. The morphometrical analysis showed an increase of size (percentage) to type I fiber than other types in all patients. Furthermore, the type I fiber had a larger cross-sectional area and mean diameter than type IIa and IIb fibers. Both histochemistry and morphometric analysis could be important tools for qualitative and quantitative diagnostics of muscle fibers attacked in this type of disease.

El objetivo del estudio fue analizar las fibras musculares mediante histoquímica y métodos morfométricos en pacientes con distrofia muscular de Duchenne (DMD). Se tomaron biopsias musculares del músculo vasto lateral de cinco niños entre 13 y 15 años de edad, con diagnóstico clínico de DMD. La histoquímica se realizó mediante ATPasa miofibrilar (9.6, 4.6 y 4.3). Para el análisis morfométrico se utilizó un sistema semiautomático computarizado y software de imagen de laboratorio. La tinción de ATPasa mostró una atrofia de las fibras musculares. La fibrosis y depósito adiposo se observó en grado variable dependiendo del compromiso muscular. El análisis morfométrico mostró un aumento de tamaño (porcentaje) de fibras tipo I en todos los pacientes. Además, la fibra tipo I tuvo un área de sección transversal y diámetro medio mayor que las fibras tipos IIa y IIb. Tanto la histoquímica y el análisis morfométrico pueden ser herramientas importantes para el diagnóstico cualitativo y cuantitativo de las fibras musculares comprometidas en este tipo de enfermedad.

Dysferlinopathy: Spectrum of pathological changes in skeletal muscle tissue.

Background: Dysferlinopathy is an autosomal recessive-limb girdle muscular dystrophy (AR-LGMD) caused due to the defect in gene encoding dysferlin, a sarcolemmal protein. Awareness of the variants and their relative frequency is essential for accurate diagnosis. Aim: To study the spectrum of morphologic changes in immunohistochemically proven cases of dysferlinopathies, to correlate the findings with clinical phenotype and durations of illness and determine the frequency. Materials and Methods: Dysferlinopathies seen over a period of 2 years at a tertiary neurological center were analyzed. Results: Clinically, majority had Miyoshi phenotype (46.6%) with distal involvement and LGMD phenotype (40%) with proximal muscle involvement. In addition, a proximo-distal and tibial muscle phenotype was encountered. Morphologically, rimmed vacuoles were noted in the Miyoshi phenotype. The presence of ragged red fibers, lobulated fibers and inflammation had no preference to a particular phenotype. Significant atrophy and lobulated fibers were noted in patients with longer duration of illness. Conclusions: Dysferlinopathy was the second most common identifiable cause (21%) of LGMD next to sarcoglycanopathies (27%).

Effect of DHEA on Recovery of Muscle Atrophy Induced by Parkinson's Disease

PURPOSE: The purpose of this study was to determine the effect of dehydroepiandrosterone (DHEA) on recovery of muscle atrophy induced by Parkinson's disease. METHODS: The rat model was established by direct injection of 6-hydroxydopamine (6-OHDA, 20 microg) into the left striatum using stereotaxic surgery. Rats were divided into two groups; the Parkinson's disease group with vehicle treatment (Vehicle; n=12) or DHEA treatment group (DHEA; n=22). DHEA or vehicle was administrated intraperitoneally daily at a dose of 0.34 mmol/kg for 21 days. At 22-days after DHEA treatment, soleus, plantaris, and striatum were dissected. RESULTS: The DHEA group showed significant increase (p<.01) in the number of tyrosine hydroxylase (TH) positive neurons in the lesioned side substantia nigra compared to the vehicle group. Weights and Type I fiber cross-sectional areas of the contralateral soleus of the DHEA group were significantly greater than those of the vehicle group (p=.02, p=.00). Moreover, extracellular signal-regulated kinase (ERK) phosphorylation significantly decreased in the lesioned striatum, but was recovered with DHEA and also in the contralateral soleus muscle, Akt and ERK phosphorylation recovered significantly and the expression level of myosin heavy chain also recovered by DHEA treatment. CONCLUSION: Our results suggest that DHEA treatment recovers Parkinson's disease induced contralateral soleus muscle atrophy through Akt and ERK phosphorylation.

Effects of Ischemic Preconditioning on the Phosphorylation of Akt and the Expression of SOD-1 in the Ischemic-reperfused Rat Skeletal Muscles / 체질인류학회지

Akt, a key protein of cell survival, can promote cell growth and survival by activations of various cellular protective factors. Ischemic preconditioning (IP) has been known to reduce ischemic injury through upregulation of phosphorylation of Akt (p-Akt). CuZn-superoxide dismutase (SOD-1), an antioxidant enzyme, scavenges reactive oxygen species and protects cell from oxidative stress by increasing the activaiton of Akt. The present study was performed to examine the effects of IP on the expression of p-Akt and SOD-1 in the ischemicreperfused rat skeletal muscles. Thirty weeks old male SD rats were divided into 4 groups, such as controls, IP, 4 hour ischemia and 4 hour ischemia with IP. For IP, commom iliac artery was occluded three times for 5 min ischemia followed by 5 min reperfusion using rodent vascular clamps. Ischemia was induced by occlusion on the same artery for 4 hours. The Tibialis anterior and Soleus were removed at 0, 1, 3, and 24 hours of reperfusion. The expressions of p-Akt (Ser 473) and SOD-1 were examined with immunohistochemistry and Western blot analysis.In the IP group, the p-Akt and SOD-1 were increased, compared to the control group. In the ischemia group, the p- Akt and SOD-1 were decreased, compared to the control group, and were more abundant when reperfusion time were increased. IP increased the p-Akt and SOD-1 after 4 hour ischemia, and the p-Akt and SOD-1 were higher in Soleus compared to Tibialis anterior. These findings suggest that IP increases p-Akt and expression of SOD-1 in the ischemic-reperfused rat skeletal muscles, and that upregulations of p-Akt and SOD-1 induced by IP were higher in the red muscle fiber, Soleus, than the white muscle fiber, Tibialis anterior.

[Effects of endurance and resistance training on calcitonin gene-related content in slow and fast twitch rat muscles]

Calcitonin Gene-Related Peptide [CGRP], a 37-amino acid peptide generated by alternative processing of primary transcripts from calcitonin gene, is broadly distributed in the peripheral and central nervous systems of vertebrate and invertebrate species, CGRP plays a main role in the neuromuscular junction. This paper investigates the effects of endurance and resistance training on the content of CGRP in the slow and fast twitch muscles. Twenty-two male Wistar rats, [age 10 mo, weight 220 +/- 20gr, Pasteur Institute] were randomly divided to three groups.] Control [n=7], Endurance training [n=7], and Resistance training [n=8]] and underwent 12 weeks training according to protocols. Animals of the resistance training group were housed in a metal cage with a wire-mesh tower; endurance training included treadmill running], 5 days a week, 60 min/day, 30 m/min speed, for animals in this group. Forty-eight hours after last session of protocols, animals were anaesthetized. The right soleus and anterior tibialis were removed, and, tissues were immediately frozen in liquid nitrogen and kept at -70°C for use later. CGRP content was measured by the ELISA method. For data analyses, one-way ANOVA was used. There was no significant difference between control and endurance training groups in the CGRP of slow and fast twitch muscles. However the content of CGRP in both fast and slow twitch muscles was significantly different in the resistance training group as compared to the control group. That training can be a main factor for CGRP release in muscles. In addition, the type and intensity of activity probably contribute to increase in CGRP content

Increased activity of sarcoplasmic reticulum Ca(2+)-ATPase in soleus of hyperthyroid rat accelerates fatigue during intermittent tetanic contraction / 生理学报

The elevated plasma level of thyroxin and/or triiodothyronine in hyperthyroidism not only induces a transition from the innervated slow-twitch muscle fibers to fast-twitch fibers, but also changes the contractile function in transition muscle fibers. So the muscle weakness of thyrotoxic myopathy would relate to alteration in fatigability of tetanic contraction in muscles, especially in slow-twitch fibers. The aim of the present study was to observe the extent of fatigue of soleus in 4-week hyperthyroid rats and elucidate its underlying mechanism. The isolated soleus muscle strips were perfused in Krebs-Henseleit solution with or without an inhibitor of sarcoplasmic reticulum Ca(2+)-ATPase (SERCA), cyclopiazonic acid (CPA). The contractile function of soleus was observed in twitch and intermittent tetanic contraction. The body weight in 4-week hyperthyroid rats decreased as compared with that in the control group [(292±13) g vs (354±10) g], but there was no difference between hyperthyroid and control groups in the wet weight of soleus [(107.3±8.6) mg vs (115.1±6.9) mg]. The time to peak tension (TPT) and time from peak tension to 75% relaxation (TR(75)) in twitch contraction were shortened in the soleus of hyperthyroid rats, and the TR(75) of tetanic contraction was also shortened as compared with that in the control group [(102.8±4.1) ms vs (178.8±15.8) ms]. The optimal stimulation frequency at which a maximal tension of tetanic contraction happened was shifted from 100 Hz in the control group to 140 Hz in hyperthyroid group. The soleus of hyperthyroid rat was easier to fatigue than that of the control rat during intermittent tetanic contraction. The SERCA activity also increased in soleus of hyperthyroid rat. The TR(75) in tetanic contraction was prolonged and showed an increased fatigue resistance in the soleus of control and hyperthyroid groups treated with 1.0 μmol/L CPA. The fatigue resistance of tetanic contraction in the soleus of hyperthyroid rat increased further with 5.0 μmol/L CPA treatment, but the resting tension kept rising. The 10 μmol/L CPA reduced the fatigue resistance of tetanic contraction in the soleus of hyperthyroid rat. The above results demonstrate that the SERCA activity in soleus can also influence the relaxation duration of twitch contraction like that in the myocardium. The SERCA activity in slow-twitch fibers is possibly involved in the regulation of fatigue resistance of intermittent tetanic contraction.

Effect of thyroid hormone on contractility and sarco/endoplasmic Reticulum Ca[2+] ATPase -1 [SERCA1] expression in adult rats; role in thermogenesis

Thyroid hormone is one of the main factors that determine skeletal muscle contractile properties and the slow-twitch vs. fast twitch muscle fiber phenotype. Sarcoplasmic reticulum Ca[2+] ATPase is one of the principal regulators of Ca[2+] homeostasis in the skeletal muscle cells. It has been previously shown that modification of thyroid hormone levels has a profound impact on cardiac function, predominantly through a direct regulation of the sarcoplasmic reticulum protein levels. The present study aimed to investigate the effects of thyroid hormone treatment for 4 weeks on slow twitch soleus muscle of rats via recording twitch tension, time to peak tension, and half relaxation time and determination of soleus muscle SERCA1 expression. 24 male rats of local strain were randomly divided into 2 groups [n=12], control euthyroid group and hyperthyroid group in which hyperthyroidism was induced by intra peritoneal [i.p] injection of L-troxin 200microg/kg B.W./day, for 4 weeks. The in-situ isometric measures were done for soleus muscle and twitch tension [TT], [expressed as screen units], time to peak tension [TPT], and half relaxation time, 1/2 Rt [expressed in milliseconds] were recorded. SERCA1 protein expression in rat soleus muscle was measured. Thyroid hormone treatment significantly reduced time to peak tension and half relaxation time and increased twitch tension. These contractile changes were accompanied with significant increase in expression of SERCA1 in soleus muscle of rats. Thyroid hormone stimulates the expression of SERCA1 in slow soleus muscle in rats, thereby speeding-up the contraction-relaxation cycle and this increases energy expenditure and these effects of thyroid hormone participate at least in part to thermogenic action of thyroid hormone

Morfologia e morfometria dos tipos de fibras do músculo reto abdominal de cadelas (Canis familiaris) durante a gestação / Morphologic and morphometry of rectus abdominis muscle fiber types of the during the gestation dog (Canis familioris)

Neste trabalho foram avaliadas as alterações morfológicas e o grau de hipertrofia das fibras de contração lentas (tipo I) e rápidas (tipo II) do músculo reto abdominal de cadelas adultas nas fases: pré-gestacional, 30 e 60 dias de gestação e 30 dias pós-parto (pp). Em todas essas fases, sob anestesia, foram removidas biópsias musculares, as quais foram congeladas. Cortes histológicos foram obtidos em um micrótomo e corados com hematoxilina e eosina (HE) para a avaliação da morfologia. Outros cortes foram submetidos à ATPase miofibrilar (m-ATPase), após pré-incubação em meio alcalino (pH = 10,4) e em meio ácido (pH = 4,4), visando à identificação das fibras tipo I e II. Nas cadelas virgens, o tecido muscular revelou-se constituído por fibras com diferentes diâmetros, com contornos poligonais, tendo um ou mais núcleos periféricos. Estas características foram similares nos animais com 30 dias de gestação. Aos 60 dias, ao lado de fibras com aparência normal, observaram-se fibras com contornos mais polimórficos e outras fibras de diâmetros muito pequenos. Aos 30 dias pp, as características do tecido foram similares às dos animais em fase pré-gestacional. Em todas as fases estudadas, os diâmetros fibras tipo II foram maiores do que as do tipo I. Aos 30 dias observou-se a redução significativa dos diâmetros de ambos os tipos de fibras e aumento significativo aos 60 dias de gestação. Durante a gestação, o estímulo crônico, representado pela expansão da parede abdominal, promoveu alterações da morfologia e morfometria das fibras.

The present paper deals with the evaluation of morphological and morphometric alterations of slow-twist (I) and fast-twitch (II) fibers of rectus abdominis muscle of adult female dog during pre-gestational phase, at 30 and 60 days of pregnancy and at 30 days after the porturition. At the every phases, using the open biopsy technique, muscle samples were collected. The samples were plunged. Histological sections were cut in a microtome. For general morphology, some sections were stained with HE. Subsequent sections were reacted for myofibrillor ATPase (m-ATPase), after alkaline (pH 10.4) and acid (pH 4.4) pre-incubations, in order to identificate type I and II fibers. In the pre-gestational phase, muscle tissue revealed to be composed by fibers with different diameters, presenting polygonal outlines and one or more periphery nuclei. At 30 days of pregnancy, muscle fiber characteristics were similar. At 60 days, in addition to the existence of normal fibers, polymorphic and small diameter fibers were frequent. At 30 days after the parturation, the morphology of muscle fiber were similar to that observed in the pre-gestational phase. In the four phases, type II fiber diameters were lager than type I. The diameters of both fiber types showed a significant reduction in the 30 days phase and a significative increasing at 60 days. The expansion of the abdominal wall during the pregnancy represents a chronic stimulus, induced changes in the morphology and in the fiber type diameters.

Metabolic and physiologic characteristics of skeletal muscle determine its response to clenbuterol treatment.

beta-Adrenoceptor agonists are reported to induce skeletal muscle hypertrophy and hence serve as valuable adjunct to the treatment of wasting disorders. In the present study, we attempted to find out whether metabolic and physiologic characteristics of fibres are important in determining skeletal muscle response to clenbuterol (an adrenergic receptor agonist) therapy, as proposed in the treatment of wasting disorders. The treatment of mice with clenbuterol (2 mg/kg body wt for 30 days) resulted in skeletal muscle hypertrophy, more common amongst fast-twitch glycolytic fibres/muscle, with increase in body mass and a parallel rise in muscle mass to body mass ratio. Measurement of fibre diameters in soleus (rich in slow-twitch oxidative fibres), ALD or anterior latissimus dorsi (with a predominance of fast-twitch glycolytic fibres) and gastrocnemius (a mixed-type of muscle) from clenbuterol-treated mice for 30 days revealed noticeable increase in the per cent population of narrow slow-twitch fibre and a corresponding decline in white-type or fast-twitch glycolytic fibres in gastrocnemius and ALD. As revealed by counting of muscle cells in soleus, narrow red fibres declined with corresponding increase in white-type glycolytic fibres population. A significant decline in the succinic dehydrogenase activity was observed, thereby suggesting abnormality in oxidative activity of skeletal muscles in response to clenbuterol therapy.

The changes of the muscular fiber phynotype at different condition of nerve injury / 中华整形外科杂志

<p><b>OBJECTIVE</b>To observe the change of the muscular fiber phynotype at different condition of nerve injury.</p><p><b>METHODS</b>Rabbits were used as an animal model in this study. The trigeminus and facial nerves of the animal were simultaneously severed (group 1) or only the latter was severed (group 2). The morphologic change of the muscular fibers was observed with histochemical methods; the tension of contraction and the threshold value of electrical stimulation were observed with electrical physiological methods.</p><p><b>RESULTS</b>Trigeminus nerve play an important role in delaying muscular atrophy after facial nerve was severed. The atrophy degree of type II a and II b muscular fibers was less in group 2 than that in group 1. The change of type 1 muscular fibers was not affected by trigeminus nerve. New muscular fibers emerged in group 2. The tension of contraction and the threshold value of electrical stimulation were better in group 2 than that of in group 1.</p><p><b>CONCLUSIONS</b>Sensory nerve could delay muscle atrophy after denervation. Sensory nerve should be repaired simultaneously when the motor nerve was sutured. The results of this study would facilitate clinical treatment for facial palsy.</p>

Cyclosporin A preferentially attenuates skeletal slow-twitch muscle regeneration

Calcineurin, a Ca2+/calmodulin-dependent phosphatase, is associated with muscle regeneration via NFATc1/GATA2-dependent pathways. However, it is not clear whether calcineurin preferentially affects the regeneration of slow- or fast-twitch muscles. We investigated the effect of a calcineurin inhibitor, cyclosporin A (CsA), on the morphology and fiber diameter of regenerating slow- and fast-twitch muscles. Adult Wistar rats (259.5 ± 9 g) maintained under standard conditions were treated with CsA (20 mg/kg body weight, ip) for 5 days, submitted to cryolesion of soleus and tibialis anterior (TA) muscles on the 6th day, and then treated with CsA for an additional 21 days. The muscles were removed, weighed, frozen, and stored in liquid nitrogen. Cryolesion did not alter the body weight gain of the animals after 21 days of regeneration (P = 0.001) and CsA significantly reduced the body weight gain (15.5 percent; P = 0.01) during the same period. All treated TA and soleus muscles showed decreased weights (17 and 29 percent, respectively, P < 0.05). CsA treatment decreased the cross-sectional area of both soleus and TA muscles of cryoinjured animals (TA: 2108 ± 930 vs 792 ± 640 µm²; soleus: 2209 ± 322 vs 764 ± 439 m²; P < 0.001). Histological sections of both muscles stained with Toluidine blue revealed similar regenerative responses after cryolesion. In addition, CsA was able to minimize these responses, i.e., centralized nuclei and split fibers, more efficiently so in TA muscle. These results indicate that calcineurin preferentially plays a role in regeneration of slow-twitch muscle.

Effect of testosterone propionate on the distribution pattern of calcitonin gene-related peptide in different motoneuron pools / 中国医学科学院学报

<p><b>OBJECTIVE</b>To study the effect of testosterone propionate (TP) on the distribution pattern of calcitonin gene-related peptide (CGRP) in two types of motoneuron (Mn) pools in rats.</p><p><b>METHOD</b>The double labeling of cholera toxin B subunit coupled with colloidal gold (CB-Au) retrograde identification combining with immunocytochemistry was mainly used to reveal the distribution pattern of CGRP-like immunoreactivity (CGRP-LI) and its changes in the motoneuron pools labeled by CB-Au.</p><p><b>RESULT</b>TP injected intramuscularly 28 days later significantly decreased CGRP expression in Mn pool innervating extensor digitorum longus (EDL, fast-twitch), comparing with corresponding control and castration group respectively (P < 0.001), while no significant effect on Mn pools innervating soleus (SOL, slow-twitch, P > 0.05) was observed.</p><p><b>CONCLUSION</b>EDL-Mn pool is more sensitive to testosterone propionate than SOL-Mn pool in regulating CGRP expression.</p>

A Case of Congenital Neuromuscular Disease with Uniform Type 1 Fiber

Congenital neuromuscular disease with uniform type 1 fiber (CNMDU1) is a rare but distinct form of nonprogressive, congenital myopathy. CMNDU1 is characterized by a type 1 muscle fiber content of more than 99%. This condition has only been previously described in a few reports. The authors report an 11-year-old girl who exhibited delayed developmental milestones, proximal muscle weakness, and bilateral ptosis. Her serum creatine kinase level was normal but an electromyographic study showed myopathic changes. A biopsy specimen from the left deltoid muscle revealed a uniformity of type 1 fibers (greater than 99%) with a moderate variation in fiber size. This is the first case of CNMDU1 reported in Korea.

Annual Report on External Quality Assessment in Diagnostic Genetics in Korea (2003) / 임상검사와정도관리

The importance of quality control for dramatically growing genetic tests continues to be emphasized with increasing clinical demands. Diagnostic genetics subcommitee of KSQACP performed two trials for cytogenetic study in 2003. Cytogenetic surveys were performed by 33 laboratories and answered correctly in most laboratories except some problems in nomenclature and analysis for FISH and complex cytogenetic abnormalities in neoplasia. The molecular genetic test surveys include M. tuberculosis, HBV, HPV, leukemia/lymphoma, ApoE genotyping, Duchenne muscular dystrophy, myoclonic epilepsy and ragged red muscle fibers, and spinal and bulbar muscular atrophy. HPV, myoclonic epilepsy and ragged red muscle fibers, and spinal and bulbar muscular atrophy were the first challenge of the genetic survey. Molecular genetic survey showed excellent results in most participants, however, HPV tests should be improved by quality control in a few laboratories. External quality assessment program for cytogenetic analysis could be helpful to give participants many chances of continuous education and of interesting case materials.