Expression Of Calcium-buffering Proteins In Rat Intrinsic Laryngeal Muscles.

Intrinsic laryngeal muscles (ILM) are highly specialized muscles involved in phonation and airway protection, with unique properties that allow them to perform extremely rapid contractions and to escape from damage in muscle dystrophy. Due to that, they may differ from limb muscles in several physiological aspects. Because a better ability to handle intracellular calcium has been suggested to explain ILM unique properties, we hypothesized that the profile of the proteins that regulate calcium levels in ILM is different from that in a limb muscle. Calcium-related proteins were analyzed in the ILM, cricothyroid (CT), and tibialis anterior (TA) muscles from male Sprague-Dawley rats (8 weeks of age) using quantitative PCR and western blotting. Higher expression of key Ca(2+) regulatory proteins was detected in ILM compared to TA, such as the sarcoplasmic reticulum (SR) Ca(2+)-reuptake proteins (Sercas 1 and 2), the Na(+)/Ca(2+) exchanger, phospholamban, and the Ca(2+)-binding protein calsequestrin. Parvalbumin, calmodulin and the ATPase, Ca(2+)-transporting, and plasma membrane 1 were also expressed at higher levels in ILM compared to TA. The store-operated calcium entry channel molecule was decreased in ILM compared to the limb muscle and the voltage-dependent L-type and ryanodine receptor were expressed at similar levels in ILM and TA. These results show that ILM have a calcium regulation system profile suggestive of a better ability to handle calcium changes in comparison to limb muscles, and this may provide a mechanistic insight for their unique pathophysiological properties.

Contribuição ao estudo do musculo abdutor do dedo minimo da mão, no homem

Orientador: Vilma Cloris de CarvalhoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Não informadoAbstract: Not informed.MestradoAnatomiaMestre em Biologia e Patologia Buco-Denta

Estimation Of The Number And Size Of Motor Units In Intrinsic Laryngeal Muscles Using Morphometric Methods.

The number and size of motor units in the intrinsic laryngeal muscles were estimated by morphometric methods. Laryngeal muscles with their respective nerve branches were obtained from 64 fresh cadavers (32 older than 60 years, mean age 74 +/- 9 years and 32 younger than 60 years, mean age 51 +/- 8 years). Myelinated nerve fibers and the total number of muscle fibers were counted. Motor unit size was estimated by dividing the total number of muscle fibers by the total number of motor units in each case. The mean number of motor units ranged from 268 +/- 1.3 (interarytenoid muscle) to 431 +/- 1.6 (cricothyroid muscle). Thyroarytenoid and cricothyroid muscle presented the smallest (9.8 +/- 0.2) and largest (20.5 +/- 0.9) motor unit size, respectively, suggesting that thyroarytenoid muscle has a greater capacity to fine-tune its total force compared with the other intrinsic laryngeal muscles. No differences in motor unit number or size were observed between the right and left sides or between younger and older subjects. It is suggested that synaptic rearrangements may occur at the level of the neuromuscular junction in the human larynx that may explain the age-related changes in motor units reported by clinical methods.21301-

Co-administration Of Deflazacort And Doxycycline: A Potential Pharmacotherapy For Duchenne Muscular Dystrophy.

The standard therapy used in the treatment of Duchenne muscle dystrophy (DMD) is corticoids, such as deflazacort and prednisone. However, they have limited therapeutic value, and their combination with drugs already in use to treat other human diseases could potentially increase corticoid outcomes in DMD. In the present study, we evaluated whether a combined therapy of the corticoid deflazacort with doxycycline could result in greater improvement in mdx dystrophy than deflazacort alone. Deflazacort alone or deflazacort/doxycycline were administered for 36 days (starting on postnatal day 0) in drinking water. Histopathological, biochemical (creatine kinase), functional (forelimb muscle grip strength and fatigue) parameters and inflammatory markers (MMP-9, TNF-α, NF-kB) were evaluated in biceps brachii and diaphragm muscles of the mdx mice. The combined therapy was superior in improving the dystrophic phenotype compared to monotherapy. The primary results were observed in attenuating muscle fatigue, decreasing muscle total calcium and inflammatory markers and increasing β-dystroglycan, a main component of the dystrophin-protein complex. Furthermore, the combined therapy was effective in preventing the loss of body mass observed with deflazacort alone at this very early stage of therapy. The present study offers preclinical data to support further studies with deflazacort/doxycycline combined therapy in DMD clinical trials.42788-79

Checking the shape and lobation of the right atrial appendage in view of their clinical relevance

Clinically, anatomy of the appendage of the atrium is associated with atrial fibrillation, with the shape and lobation of the appendage having been used to stratify the risk of thromboembolic events. The aim of this study was to examine the age-dependent change in the shape and lobation of the right atrial appendage. A cross-sectional evaluation of the heart of 172 adults and 61 children, fixed in 4% formalin solution was performed. The morphology of the atrial appendage was assessed based on its shape and number of lobes. The following shapes of the appendage were identified: horse head, parrot beak, anvil, sailboat, and undefined. Using the horse head shape as a reference, the risk for a thromboembolic event was higher for anvil, sailboat and undefined shapes of the appendage (p<0.001). The number of lobes ranged between 1 and 6 in adults, and 1 and 5 in children. The number of lobes for each shape was equivalent between adults and children (p>0.05). Our analysis indicated that the number of lobes and the distribution of shapes of the atrial appendage remained unchanged throughout life. The risk for a thromboembolic event increased with the morphological complexity of the appendage (anvil, sailboat, and undefined), with 21% of adult hearts being prone to intra-atrial thrombosis in cases of fibrillation944324329CNPQ - Conselho Nacional de Desenvolvimento Científico e Tecnológico302831/2013-4; 303320/2013-3; 141228/2017-

Insights Into The Loss Of Muscle Mass Following B. Jararacussu Venom In Mice.

Bothrops jararacussu snake venom produces myonecrosis and nerve degeneration. In this work, we investigated whether nerve lesions or impaired muscle regeneration contributed to the permanent loss of muscle mass, a long-term sequela of envenoming. The right soleus muscle of adult male mice was injected with B. jararacussu venom (80 microg) while the left muscle received only saline (control). The mice were killed after 2 and 3 months and the muscles were removed and processed for examination by transmission electron microscopy and light microscopy. The nerve fibers, Schwann cells and neuromuscular junctions had regenerated in venom-treated muscle. The total number of muscle fibers was significantly lower (p<0.05) than in the control (617+/-48 versus 1235+/-97, respectively; mean+/-SEM, n=10). These results show that the loss of muscle mass was most likely related to a decrease in the ability of the muscle to regenerate rather than to nerve lesions.44847-5

Immunolocalisation of neuronal nitric oxide synthase at the neuromuscular junction of MDX mice: a confocal microscopy study

The distribution of nitric oxide synthase at the neuromuscular junction (NMJ) of normal, denervated and mdx mice was studied using a specific antibody against the neuronal isoform of nitric oxide synthase (nNOS). Fluorescence confocal microscopy demonstrated that nNOS immunoreactivity was localised mainly in the sarcolemma and presynaptic region covering acetylcholine receptor branches. The expression of presynaptic nNOS was greatly reduced in dystrophin-deficient muscles. In normal denervated muscles, nNOS was still present in the presynaptic region and there were no qualitative changes in the expression of this protein. These results suggest that the presynaptic distribution of nNOS is associated with terminal Schwann cells. The relationship between nNOS and the presynaptic components of the neuromuscular junction may open new perspectives for improving our understanding of the pathogenesis of dystrophic muscles

Cryopreserved Muscle Basal Lamina Grafts Retain Their Grafting Potential For Nerve Repair.

The development of alternatives to nerve autografts for nerve repair remains a goal of surgeons. Muscle basal lamina grafts have a potential use as bioprostheses, but it is not known whether such grafts retain their ability to support axonal regeneration following storage. In this study, we examined the effect of cryopreservation on the ability of muscle basal lamina grafts to repair nerve lesions. Basal lamina grafts were prepared and cryopreserved for different times and at different temperatures. Their grafting potential was evaluated by examining axonal regeneration after autografting to lesions in rat sciatic nerves. Muscle basal lamina grafts cryopreserved for up to 30 weeks at -20 and -40 degrees C were successfully used. There were no significant differences in the parameters of axonal regeneration between cryopreserved and non-cryopreserved grafts. In conclusion, muscle basal lamina autografts retain their potential usefulness for nerve repair after cryopreservation, providing a basis for the development of a bioprostheses from muscle basal lamina.50112-

Acute Local Nerve Lesions Induced By Bothrops Jararacussu Snake Venom.

Myonecrosis is one of the most common effects of Bothrops jararacussu venom, but little is known about the action of this venom on other tissues. In this study, we used transmission electron microscopy to examine the influence of B. jararacussu venom on nerve tissue. A sublethal dose of venom (80 microg) was injected into the tibialis anterior muscle of mice which were then killed at various intervals up to 6 h after venom injection. The venom caused massive, progressive axonal damage beginning 2 min after inoculation and after 6 h, all intramuscular nerve bundles were completely depleted of nerve fibers. The most striking finding was myelin breakdown. The ultrastructural changes observed and the time course of the nerve lesions indicated that B. jararacussu venom acted directly on nerve tissue, possibly on the phospholipids of the myelin sheath. The axonal damage reported here may be of relevance to explain, at least in part, the muscular atrophy and poor recovery in muscle function seen in human and experimental envenomations.401483-

Surgical Anatomy Of The Guyon Canal In Children.

The anatomy of the Guyon canal is crucial for open and endoscopic surgeries for ulnar canal syndrome at the wrist level. It is also of interest for surgical treatment of carpal canal syndromes. Whereas the Guyon canal is largely described in adults, no studies exist in children. In the present study, the authors examined the Guyon canal in children. Sectional anatomy was used. Thirty-two formalin-fixed cadavers (64 sides) were examined (age range 2-11 years). The hands were transversely cut into 2-3-mm-thick slices. Slices were placed in embedding medium, and transverse sections (10 μm thick) were stained with histological methods and photographed under a light microscope. The roof of the Guyon canal was attached to the flexor retinaculum laterally to the hamulus of the hamate bone. Thus, the radial boundary of the Guyon canal was lateral to the hamulus, which became part of the floor of the Guyon canal. An ulnar neurovascular bundle was found directly volar to the hamulus in 93.8% of the cases and slightly medial to the hamulus (to the ulnar side) in 6.2% of the cases. Proximally, the ulnar artery and nerve were sustained by the flexor retinaculum in direct apposition to the carpal canal. In children, the Guyon canal displays an anatomical particularity regarding the topography of the ulnar artery and nerve that may be of relevance for intraoperative orientation and endoscopic navigation to avoid lesions to the ulnar nerve and artery in carpal and Guyon canal syndromes.7286-