Muscular Elements Research Articles

Sensorimotor Elements of the Orofacial System: Reviewing the Basics

Abstract The functional ability of the central nervous system (CNS) to transduce and process sensory information directly associated with voluntary action is believed to be an important element in sensorimotor learning and skill acquisition for the orofacial system. Muscles of the lower face insert directly into the facial skin, allowing for sensory endings to encode both the static and dynamic consequences of force and movement related to orofacial behavior. These task-related inputs are subsequently made available to sensorimotor cortices whose functions are known to be highly responsive to the consequences underlying precise adjustments in force during skilled motor control. The purpose of this article is to provide a basic review of the fundamental muscular and sensory elements contributing to orofacial sensorimotor control. In addition, select research on sensorimotor integration in the orofacial system will be summarized with a discussion on the importance of these findings in the context of orofacial rehabilitation.

From Vision to Mission in Myocardial Restoration

What do myocardial restoration and hyperspace theory have in common? The usual perception of tissue engineering, the fl edgling new science, is of an art in 3 dimensions aimed at the reproduction of natural tissue in terms of structure and function. However, in the case of the heart, more than 3 dimensions need to be realized: the 4 th is the heart rhythm, and the 5 th is the contractile action and mechanics. Any ambitious attempt to manufacture cardiac muscle will have to address some unique issues if the product is to be one of high fi delity to nature. In the following, some important aspects of myocardial restoration will be discussed. Some 10 years ago, aspiring tissue engineers and heart surgeons such as us, stood up and stated that Homo sapiens would be producing the fi rst bioartifi cial left heart chamber within the decade. Unfortunately this prediction has proven premature, if not naive. This is for obvious reasons. First, the heart is a highly asymmetric organ. The architecture of the diverse portions of the heart differs from site to site. The left ventricle is built differently from the right, and fulfi lls its function on a different scale. Furthermore, the form of the heart is not that of a simple sphere. Would it be so, then the maximal possible ejection fraction would not exceed 15%. The heart comprises a helix of uniquely arranged muscular bands (Torrent-Guasp bands), overlaying each other at an angle of approximately 60°. 1 During systole, the heart functions as a vortex, thereby exploiting the maximal power possible from the muscular elements. These unique properties have not even been addressed so far by tissue engineering. All constructs without exception have been built in a symmetric fashion. With the available technology, it may be possible to produce a 3-dimensional graft that is shaped with 3 overlying layers and can be excited to twist as a vortex, but the idea has not been approached systematically so far. What has been achieved in the recent past is a mixture of collagen scaffolds and cells, and some 2-dimensional mechanical training of the constructs. 2

Gamma-aminobutyric acid and related molecules in the sea fan Eunicella cavolini (Cnidaria: Octocorallia): a biochemical and immunohistochemical approach

The aim of this study has been the biochemical demonstration of the presence of gamma-aminobutyric acid (GABA) in the Mediterranean sea fan Eunicella cavolini by means of high-performance liquid chromatography, and the description of the distribution pattern of GABA and its related molecules, glutamic acid decarboxylase (GAD), vesicular GABA transporter (VGAT) and one of the GABA receptors (GABA(B) R) by immunohistochemical methods. The interrelationships of GABA, GAD and GABA receptor immunoreactivity have been established by using double-immunohistochemical methods and confocal microscopy. The immunodetection of monoclonal and/or polyclonal antibodies has revealed GABA immunoreactivity throughout the polyp tissue, both in neuronal and non-neuronal elements. GAD immunoreactivity has been mostly localized in the neuronal compartment, contacting epithelial and muscular elements. GABA(B) R immunoreactivity appears particularly intense in the nematocytes and in the oocyte envelope; its presence in GAD-immunoreactive neurons in the tentacles suggests an autocrine type of regulation. Western blot analysis has confirmed that a GABA(B) R, with a molecular weight of 142 kDa, similar to that of rat brain, is present in E. cavolini polyp tissue. The identification of the sites of the synthesis, vesicular transport, storage and reception of GABA strongly suggests the presence of an almost complete set of GABA-related molecules for the functioning of the GABAergic system in this simple nervous system. The distribution of these different immunoreactivities has allowed us to hypothesize GABA involvement in nematocyst discharge, in body wall and enteric muscular contraction, in neuronal integration and in male gametocyte differentiation.

High-resolution fate map of the snail Crepidula fornicata: The origins of ciliary bands, nervous system, and muscular elements

The littorinimorph gastropod Crepidula fornicata shows a spiralian cleavage pattern and has been the subject of studies in experimental embryology, cell lineage, and the organization of the larval nervous system. To investigate the contribution of early blastomeres to the veliger larva, we used intracellular cell lineage tracers in combination with high-resolution confocal imaging. This study corroborates many features derived from other spiralian fate maps (such as the origins of the hindgut and mesoderm from the 4d mesentoblast), but also yields new findings, particularly with respect to the origins of internal structures, such as the nervous system and musculature that have never been described in detail. The ectomesoderm in C. fornicata is mainly formed by micromeres of the 3rd quartet (principally 3a and 3b), which presumably represents a plesiomorphic condition for molluscs. The larval central nervous system is mainly formed by the micromeres of the 1st and 2nd quartet, of which 1a, 1c, and 1d form the anterior apical ganglion and nerve tracks to the foot and velum, and 2b and 2d form the visceral loop and the mantle cell. Our study shows that both first and second velar ciliary bands are generated by the same cells that form the prototroch in other spiralians and apparently bear no homology to the metatroch found in annelids.

Imbalance of mononuclear cell infiltrates in the placental tissue from foetuses after spontaneous abortion versus therapeutic termination from 8th to 12th weeks of gestational age

Placental macrophages (Hofbauer cells) are located close to trophoblastic cells and foetal capillaries, which make them perfect candidates for involvement in regulatory processes within the villous core. Their capacity of producing several cytokines and prostaglandin-synthesising enzymes, and expressing vascular endothelial growth factor, indicate a possible role in placental development and angiogenesis in order to support pregnancy. Common cells to Hofbauer macrophages sharing similar cell surface markers (HLA-A, -B, -C and leukocyte common antigen) have been reported in the stroma, decidua and amnion, indicating additional foetal protection. Yet this is not always the case. Most spontaneous abortions occur before 12 weeks' gestation, and most are due to chromosomal errors in the conceptus. Relatively few truly spontaneous abortions take place between 12 and 20 weeks' gestation. Thereafter, between 20 and 30 weeks, another type of premature spontaneous termination becomes prevalent, which is due to ascending infection. The numbers of cells expressing the various markers of the monocytemacrophage lineage change throughout pregnancy. In the present study, we investigated the immunohistochemical expression of mononuclear infiltrations in paraffin-embedded placentas, from foetuses after spontaneous abortion (8th, 10th and 12th weeks of gestational age), and those after therapeutic abortion at the same time, using a panel of monoclonal antibodies for the identification of leukocytes (CD45/LCA), B-lymphocytes (CD20/L-26), T lymphocytes (CD45RO/UCHL1), CD68 and CD14 cells. Immunologic factors in human reproductive failure are plausible mechanisms of infertility and spontaneous abortion. Approximately 25% of cases of premature ovarian failure appear to result from an autoimmune aetiology. Unfortunately, current therapeutic options for these women are limited to exogenous hormone or gamete substitution. Local inflammations at the sites of endometriosis implants are postulated to mediate the pain and reduced fecundability associated with this clinical syndrome. The recruitment of immune cells, particularly monocytes and T-cells, neovascularisation around foci of invading peritoneal lesions, and the possible development of antiendometrial autoantibodies support an immunologic basis of this disorder. To date, treatment of pain and infertility associated with endometriosis is primarily surgical, although immune-based adjuvants are theoretical possibilities for the future. Finally, although hypotheses supporting immunologic mechanisms of recurrent pregnancy loss have been popular over the past decade, most clinical investigations in this area do not provide compelling evidence for this position. Reputable specialists in reproductive medicine use experimental immunotherapies judiciously in selected cases of repetitive abortion. For example, the use of anticoagulation therapy can be beneficial in cases with documented antiphospholipid antibodies. At present, however, efficacious immunotherapy protocols for general application have not been established. Despite these caveats, continued strides in our understanding of human reproductive immunology should yield considerable future progress in this field. During the physiological changes that occur in the first and in the beginning of the second trimester of pregnancy, spiral arteries of the placental bed are converted into the uteroplacental arteries. The essence of this conversion consists of losing the muscular elements in the vessel walls, making them unable to respond to vasomotor influences. Cells that infiltrate the walls of spiral arteries and replace their normal elements are called migratory, non-villous or intermediate trophoblastic cells. Besides infiltrating and replacing the anatomic structures of spiral arteries, intermediate trophoblastic cells also penetrate into the lumina of these vessels forming endovascular plugs. These plugs are one of the reasons why early uteroplacental blood flow cannot be visualised, even with transvaginal ultrasound, during the first 12 weeks of gestation. In uncomplicated pregnancies, the endovascular trophoblast is bound to disappear by the end of the second trimester of pregnancy, but the literature on this topic is scarce. Here we describe the detection, isolation and characterisation of CD45RO-, L26- and CD68/CD14-positive cells from human early pregnancy deciduas. These cells were found in close vicinity to endometrial glands, with preference to the basal layer of the decidua. We conclude that (1) maternal cells, apparently CD45RO/UCHL1-positive cells, cross the maternofoetal barrier and participate in spontaneous (involuntary) abortions, and (2) a small proportion of maternal cells (approximately 30%), apparently CD68/CD14-positive cells, also cross the maternal-foetal barrier and cause growth delay and recurrent reproductive failure. Further investigation of involvement of the intercellular adhesion molecules 1 and 2, platelet endothelial cell adhesion molecule, vascular cell adhesion molecule and E-selectin in leukocyte accumulation will be needed to support the passage of maternal cells to the foetus. The results were statistically significant (P<0.0001, Student's t-test).

Morphology of Xenodasys (Gastrotricha): the first species from the Mediterranean Sea and the establishment of Chordodasiopsis gen. nov. and Xenodasyidae fam. nov.

During a survey of the Italian marine meiofauna, several specimens of the rare gastrotrich genus Xenodasys were found in a submarine cave along the Ionian coast of Apulia. The finding represents the first record of the genus for the Mediterranean Sea and reinforces the consideration of marine caves as habitats of high naturalistic value. The specimens, analysed using different microscopy techniques, showed a new species, named Xenodasys eknomios. Scanning electron microscopy, unveiling the astonishing morphology of this unusual gastrotrich, indicates that, due to technical artefacts, light microscopy may generate unreal features, which in the past may have led to the misinterpretation of the anatomical traits of these creatures. Transmission electron microscopy indicated that the ‘Seitenfüsschen’, are genuine elements of the adhesive apparatus, in contrast with previous investigation, which attributed an exclusive sensorial function to these organs. Confocal laser scanning microscopy, combined with actin-binding fluorochromes, revealed muscular elements in a region where originally the muscular chordoid organ was reported for gastrotrich species belonging to the genus Chordodasys. A taxonomic revision of the species currently allocated to the genus Xenodasys led to the establishment of Chordodasiopsis gen. nov. to integrate the former Xenodasys (=Chordodasys) antennatus and to the drafting of emended diagnosis of the genus Xenodasys. An overview of the high-rank systematization of these genera is also provided, with the establishment of Xenodasyidae fam. nov. to allocate both Xenodasys and Chordodasiopsis.

Face Mask Free Flap: Description of Cadaver Dissection Technique and Anatomy

Between July 1989 and July 2003, in the research laboratory for face muscles, Second Chair of Anatomy of the Medical Faculty of the University of Buenos Aires, 40 cadavers were dissected. The dissection was from superficial to deep, and after exposing deep muscular tissue, dissection of the bulk of facial muscular elements was carried out from the depth to the surface. The following results were obtained: 1. the anatomic bases to perform a face mask free flap; 2. a description of the main vascular systems; 3. a description of neural motor innervation; 4. a description of neural sensitive innrvation.

Effects of hypoglossal and facial nerve injuries on milk-suckling

Functional roles of the perioral anatomical structures involved in breastfeeding were examined in newborn rat pups in which the hypoglossal (XII) and facial (VII) nerves had been resected at the neonatal stage. The XII nerve controls tongue movement and is comprised of two functionally distinct branches: the medial branch related to protrusion of the tongue and the lateral branch related to its retraction. Newborn rat pups with bilateral resection of either of the XII nerve components (main trunk: XII-trunk; medial branch: XII-med; lateral branch: XII-lat) failed to suckle milk and did not survive. Unilateral XII nerve-resected neonates showed different milk-suckling capabilities, which thus resulted in differences in survival rate (XII-trunk: 38%; XII-med: 24%; XII-lat: 92%) and postnatal growth during the postnatal 3 weeks until P21. Unilateral and bilateral resections of the VII nerve innervating the buccolabial musculature produced lowered suckling capabilities and retarded postnatal growth, although all pups showed 100% survival. The results indicate a crucial role of the tongue, especially of protruding muscular elements innervated by the XII-med nerve, in breastfeeding. The results also indicate differential effects of the VII and XII nerve components on suckling capability, survival, and postnatal growth of newborn rat pups.

Core Stability and Its Relationship to Lower Extremity Function and Injury

Core stability may provide several benefits to the musculoskeletal system, from maintaining low back health to preventing knee ligament injury. As a result, the acquisition and maintenance of core stability is of great interest to physical therapists, athletic trainers, and musculoskeletal researchers. Core stability is the ability of the lumbopelvic hip complex to prevent buckling and to return to equilibrium after perturbation. Although static elements (bone and soft tissue) contribute to some degree, core stability is predominantly maintained by the dynamic function of muscular elements. There is a clear relationship between trunk muscle activity and lower extremity movement. Current evidence suggests that decreased core stability may predispose to injury and that appropriate training may reduce injury. Core stability can be tested using isometric, isokinetic, and isoinertial methods. Appropriate intervention may result in decreased rates of back and lower extremity injury.

Neuroeffector Connections of Giant Multimodal Neurons in the African Snail Achatina Fulica

A new method of making preparations was used to analyse the neuroeffector connections of the paired giant neurons of the African snail Achatina fulica. These neurons were found to induce postsynaptic potentials in the muscles of the mantle, heart, the wall of the pulmonary cavity, and the muscular elements of the renal complex, the pericardium, the sexual apparatus, the walls of the cerebral arteries, the filaments of the columellar muscles, the wall of the abdomen, and the tentacle retractor muscles. Rhythmic neuron activity led to the development of marked facilitation and long-term potentiation of synaptic potentials. The possible significance of the multiple neuroeffector connections of giant neurons is discussed.

Décompression orbitaire au cours des ophtalmopathies basedowiennes

Graves' ophthalmopathy is a complex orbital condition with a controversial pathogenesis. It is the clinical expression of a discordance between the inextensible orbit and hypertrophic muscular and fatty elements within the orbit responding to immunological stimulation. The relationship between the orbital and its content can be improved by surgical expansion which increases the useful volume of the orbit. This procedure can be combined with lipectomy to decrease the volume of the orbital contents. We briefly recall the history of surgical decompression techniques and present our experience with Graves' ophthalmopathy patients.

Fibrous Hamartoma of Infancy: A Case Report

A 10-year-old Nepalese boy presented with a 5-year history of a progressively enlarging, asymptomatic tumour on the left side of the face. The lesion began as a skin-coloured nodule, which gradually enlarged over a period of time. There was a history of recent rapid enlargement after the incisional biopsy. No history of similar skin lesion was found in the family. His general physical and systemic examinations were unremarkable. The cutaneous examination revealed a solitary, firm, pedunculated, non-tender, 1068 cm tumour with lobulated surface over the left parotid region (Fig. 1). The tumour was softened and ulcerated in some areas; and was associated with sero-sanguinous discharge and thick crust. The overlying temperature was normal. The tumour was not fixed to the underlying tissues. The oral examination did not reveal any abnormalities. The differential diagnoses of pilomatricoma and parotid malignancy were made. Wedge biopsy was performed for histopathological examination but it showed only myxoid tissue; therefore, it was difficult to draw a final conclusion. Keeping in mind the differential diagnoses, the tumour was subsequently excised completely and sent for histopathological examination. Gross examination of the specimen revealed a poorly circumscribed tumour containing an intimate mixture of firm grey-white tissue and fat. The cut surface showed multiple small and large cystic and solid areas. Cystic spaces were filled with mucoid material. Histopathological examination revealed a characteristic organoid pattern composed of intersecting trabeculae of fibrous tissue and collagen. There were loosely textured areas of mucoid matrix with spindle-shaped, round or stellate cells and interspersed mature adipose tissue. No muscular elements or cell atypia were observed. These features were consistent with a diagnosis of fibrous hamartoma of infancy. No recurrence was noted during the next 6 months of follow-up.

AGA technical review on the clinical use of esophageal manometry

AGA technical review on the clinical use of esophageal manometry

Anatomical relationships between selected segmental muscles of the lumbar spine in the context of multi-planar segmental motion: a preliminary investigation

In the last decade, concepts regarding spinal stability have been redefined. Whereas traditional stability models considered only the integrity of the intervertebral disc and spinal ligaments, mechanisms contributing to spinal stability are now thought to include neural and muscular elements. Lumbar muscles capable of generating intersegmental stiffness are considered necessary for the control of multi-planar segmental spinal motion. The transversus abdominis, psoas, quadratus lumborum and multifidus have each been described functionally as contributing to segmental motion control in the lumbar spine. However, the fundamental anatomy of these muscles has not been fully established nor have their architectural characteristics as a functional group been explored. A dissection of the lumbar spine was undertaken to document the attachments of the deep vertebral muscles and illustrate their group architectural characteristics in the context of multi-planar segmental motion. The transversus abdominis, psoas, quadratus lumborum and multifidus were each noted to have segmental attachment patterns in the lumbar spine. As a group, they surround the lumbar motion segments from the anterolateral aspect of a vertebral body to the spinous process. A hypothetical role for this muscle group in maintaining lumbar spine stability is discussed as are suggestions for future research.

An AcrobatTM-based program for gross anatomy revision

Context and setting Our Department of Anatomy uses mainly prosected specimens to teach topographic anatomy to over 400 medical and 500 science, medical physics and biomedical engineering students each year. In addition, we provide distance learning courses for students of safety science. Why the idea was necessary Body donation legislation in our state makes retention of prosected tissue (whether in the dissecting room or in our Anatomy Museum) for more than 4 years extremely difficult. At the same time, funding pressures have reduced the number of skilled staff available for the preparation of quality prosections. These factors make the provision of quality prosected material for student revision problematical. The delivery of distance learning courses also demands a computer-based, self-directed learning and revision program for interstate and overseas students. Modules in the revision program need to be quickly and easily constructed by academic staff from quality digital images of actual specimens and other material which students encounter in their classes and assessments. The modules need to be easily modified to cater to varied levels of detail in our courses. What was done High quality digital images of dissected cadaveric specimens (both wet and plastinated), radiographs and skeletal material were made with the aid of a Leaf Lumina SystemsTM camera. Over 400 images were incorporated into our program, covering all regions of the body and ranging from single isolated internal organs to detailed dissections of neurovascular and muscular elements in the neck, thorax, abdomen, limbs and pelvis. Images were grouped into regional or systematic modules (as appropriate to particular courses) and incorporated into an Adobe AcrobatTM 6.0 template. Structure identification is self-tested with the aid of up to 25 hot-spotted, coloured digital flags per zoomable image panel, which the course authority can place over objects of interest. Students may use these flags in any of 3 ways: in ‘flag’ mode a brief description appears when the cursor is placed over the flag; in ‘name’ mode students click on a flag and choose the correct identification from a pull-down menu, and in ‘quiz’ mode students are asked to correctly identify structures drawn at random for that panel. Up to 6 multiple-choice question flags are included for each image, with random sequencing of options on repeated attempts. The program also generates an index allowing students to quickly locate structures of interest anywhere in the program. Academic staff can produce each image panel within 30–50 minutes, depending on the number of structures and level of question difficulty. Evaluation of results Approximately 250 copies of the program are produced and distributed on demand each year, with students sharing copies between colleagues. Ready availability of the program reduces wear and tear on precious human prosections, while providing students with a convenient revision tool for use at home. The generic nature of the template means that units can be easily tailored for specific groups of students using actual teaching material they will encounter during assessment.

Segmental Arterial Mediolysis: Angioplasty of Bilateral Renal Artery Stenoses with 2-Year Imaging Follow-up

Segmental arterial mediolysis (SAM) is a rare condition caused by loss of muscular elements in the walls of medium-sized, usually visceral, arteries. This causes dissection, occlusion, aneurysm formation, and rupture. The clinical presentation is usually catastrophic as a result of vascular occlusion or rupture. Herein an unusual case of renovascular hypertension resulting from SAM is reported, which was successfully treated with balloon angioplasty.

The occurrence of unusual smooth muscle bundles expressing α-smooth muscle actin in human intestinal atresia

Background/Purpose: Intestinal dysmotility is an important problem in the postoperative management of patients with intestinal atresia (IA). Changes in the intramural components have so far been histochemically and immunohistochemically examined in both the proximal and distal segments of IA, but no detailed analysis of the muscular elements has been performed. The aim of this study was to carefully examine any alterations in the muscular elements in the intestines from patients with IA. Methods: Resected intestines were obtained from 6 patients with ileal atresia, 4 patients with jejunal atresia, and 3 controls without gastrointestinal diseases obtained by autopsy (congenital diaphragmatic hernia). All specimens were immunochemically stained with a monoclonal antibody to α-smooth muscle actin (α-SMA) as a smooth muscle marker. Results: In the normal small intestine, almost all the enteric smooth musculature were positive for α-SMA antiserum, except for the bulk of the circular musculature. In the proximal segments of all cases with IA, a reduced staining intensity for α-SMA was observed mainly in the severely hypertrophic muscle layers. In addition, some bundles of smooth muscle also were located in the submucosal connective tissue near the border of the innermost layer of the circular musculature, in which large amounts of smooth muscle fibers extended occasionally from the innermost layer of the circular musculature to the muscularis mucosae in the proximal segments of 4 cases. In the distal segments of IA, the distribution of α-SMA–positive smooth muscle fibers was similar to that in the control intestines, excluding mild to moderate hypertrophy of the muscular layers. Conclusions: Both severe hypertrophy and a reduced immunoreactivity for α-SMA were observed in the circular muscle layer of the proximal segments. In addition, the occurrence of α-SMA–positive abnormal smooth muscle fibers was recognized in the submucosal layers of the proximal segments, thus, suggesting a delay in the intestinal muscular formation or a regressive reaction secondary to dilatation. These muscular alterations in the proximal segments might be considered to contribute to the postoperative intestinal dysmotility in IA cases. J Pediatr Surg 38:161-166. Copyright 2003, Elsevier Science (USA). All rights reserved.

Embryonic development of the myenteric nerve plexus in the rat small intestine as revealed by light and scanning electron microscopy.

This study was performed to clarify developmental changes in the structure of the myenteric nerve plexus in the rat small intestine. The small intestines of fetal and neonatal rats were examined by light microscopic immunohistochemistry for protein gene product 9.5 (PGP-9.5) and alpha-smooth muscle actin (alpha-SMA). Direct observation of the three-dimensional structure of the neuronal and muscular elements was accomplished by scanning electron microscopy of tissues after KOH treatment. At the embryonic day 14 (E14), PGP-9.5 immunopositive (neuronal) cells first appeared in the mesenchymal tissue outside an alpha-SMA positive (muscle) cell layer. These cells increased in number to form a thin and continuous sheet, which was sandwiched between the inner and outer muscular layers at E17. This neuronal layer consisted of immature ganglion cells associated with supportive (enteroglial) cells, and was gradually segregated into groups by incomplete separation through slit-like interruptions at E18. With the widening of these slits at E19, the neuronal sheet was observed as a ladder composed of transversely elongated ganglia and their connecting nerve strands, resulting in the typical structure of the myenteric nerve plexus. Fibroblastic cells of a peculiar shape appeared on the outer surface of the myenteric plexus at E19. These cells (presumably interstitial cells) interconnected their long branching projections to form a cellular network on the myenteric plexus until birth.

Motoneuron and sensory neuron plasticity to varying neuromuscular activity levels.

The size and phenotypic properties of the neural and muscular elements of the neuromuscular unit are matched under normal conditions. When subjected to chronic decreases or increases in neuromuscular activity, however, the adaptations in these properties are much more limited in the neural compared with the muscular elements.

Motoneuron and sensory neuron plasticity to varying neuromuscular activity levels.

The size and phenotypic properties of the neural and muscular elements of the neuromuscular unit are matched under normal conditions. When subjected to chronic decreases or increases in neuromuscular activity, however, the adaptations in these properties are much more limited in the neural compared with the muscular elements.