Pharynx Muscles Research Articles

Don't Hold Your Breath

Competitive breath-holders can float face down in a pool for more than 4 minutes, and the world record is 11 minutes 35 seconds. That can't be good for their brains, right? To find out, researchers at Lund University in Sweden had nine trained breath-holders lie face-up on a couch and hold their breath to mimic the so-called static apnea pool competition. The breath-holders started with their normal warm-up routines: hyperventilation and “lung packing” (using tongue and throat muscles to force extra air into the lungs). Then they stopped breathing for an average of 5.5 minutes. The volunteers' blood oxygen levels dropped by almost 80%, and concentrations of the protein S100B—a standard marker for brain damage—increased by 37%, the researchers reported online 2 July in the Journal of Applied Physiology . S100B is normally found inside brain cells and fluid but seeps into the bloodstream when an injury disrupts the brain's protective blood-brain barrier. The breath-holders' concentrations were lower than those seen in stroke or traumatic brain injury patients, and the levels recovered after 2 hours. “We probably only saw a temporary opening of the blood-brain barrier,” says researcher Johan Andersson, but he warns that it is unclear if repeated barrier openings might produce long-term brain damage. Ralph Potkin, a pulmonologist at the Beverly Hills Center for Hyperbaric Medicine in Los Angeles, California, calls the findings “disconcerting.” But John Fitz-Clarke, a diving physiologist at Dalhousie University in Halifax, Canada, says that “it's way too premature to draw any conclusions about brain damage” from these findings.

Oral vs. pharyngeal dysphagia: surface electromyography randomized study

BackgroundA clear differential diagnosis between oral and pharyngeal dysphagia remains an unsolved problem. Disorders of the oral cavity are frequently overlooked when dysphagia/odybophagia complaints are assessed. Surface electromyographic (sEMG) studies were performed on randomly assigned patients with oral and pharyngeal pathology to evaluate their dysphagia complaints for the sake of differential diagnosis.MethodsParameters evaluated during swallowing for patients after dental surgery (1: n = 62), oral infections (2: n = 49), acute tonsillitis (3: n = 66) and healthy controls (4: n = 50) included timing and amplitude of sEMG activity of masseter, infrahyoid and submental muscles.ResultsThe duration of swallows and drinking periods was significantly increased in dental patients and was normal in patients with tonsillitis. The electric activity of masseter was significantly lower in Groups 1 and 2 in comparison with the patients with tonsillitis and controls. The submental and infrahyoid activity was normal in dental patients but infrahyoid activity in patients with tonsillitis was high.ConclusionDysphagia following dental surgery or oral infections does not affect pharynx and submental muscles and has clear sEMG signs: increased duration of a single swallow, longer drinking time, low activity of the masseter, and normal range of submental activity. Patients with tonsillitis present hyperactivity of infrahyoid muscles. These data could be used for evaluation of symptoms when differential dental/ENT diagnosis is needed.

Development of a Biometric System for the Measurement of Swallowing Motion While Drinking Beer

The sensation in the throat while drinking is important for beer. To evaluate this feeling, we developed a noninvasive biometric system for measurement of the swallowing motion while drinking. The system measures movement of the Adam's apple and provides an electromyogram (EMG) of the throat musculature and swallowing sounds by simultaneously employing pressure sensors, EMG electrodes, and microphones, all mounted on the throat surface. As analytic parameters, we used the period of larynx heave, throat muscular activity, and intervals of swallowing sound. Three beer samples with different throat sensation features confirmed by sensory evaluation were investigated. The subjects swallowed beer for 15 sec successively to measure throat movement while drinking a glass of beer. The difference in laryngeal movement time and swallowing sound intervals was significant. It was determined that a sample with a light finish, ease of drinking, and drinkable sensation had short laryngeal movement time, low muscular activity, and small swallowing sound intervals. It was suggested that the sensation in the throat could be an important factor in beer drinkability. It is expected that this system could characterize the difference in swallowing motion while drinking beer and the sensation in the throat.

Knockdown of SKN-1 and the Wnt effector TCF/POP-1 reveals differences in endomesoderm specification in C. briggsae as compared with C. elegans

In the nematode, C. elegans, the bZIP/homeodomain transcription factor SKN-1 and the Wnt effector TCF/POP-1 are central to the maternal specification of the endomesoderm prior to gastrulation. The 8-cell stage blastomere MS is primarily a mesodermal precursor, giving rise to cells of the pharynx and body muscle among others, while its sister E clonally generates the entire endoderm (gut). In C. elegans, loss of SKN-1 results in the absence of MS-derived tissues all of the time, and loss of gut most of the time, while loss of POP-1 results in a mis-specification of MS as an E-like cell, resulting in ectopic gut. We show that in C. briggsae, RNAi of skn-1 results in a stronger E defect but no apparent MS defect, while RNAi of pop-1 results in loss of gut and an apparent E to MS transformation, the opposite of the pop-1 knockdown phenotype seen in C. elegans. The difference in pop-1(−) phenotypes correlates with changes in how the endogenous endoderm-specifying end genes are regulated by POP-1 in the two species. Our results suggest that integration of Wnt-dependent and Wnt-independent cell fate specification pathways within the Caenorhabditis genus can occur in different ways.

Becoming Bach, Blaspheming Bach: Kinesthetic Knowledge and Embodied Music Theory in Ysaye's "Obsession" for Solo Violin

This essay explores kinesthetic musical knowledge: what can it tell us about music, performer, or composer? In discussing my own experience of performing Obsession, first movement of violinist-composer Eugene Ysaye's Sonata No. 2 for Solo Violin, op. 27 (1923), I'll articulate some of observations I made while learning to play it. These insights in turn inflect and clarify my relationship with Bach, whose violin music is object of Ysaye's obsession. In course of practicing and performing Obsession, I have developed a reading of this piece depicting not only Ysaye's purported obsession with Bach, but also his possession by (a demonic) Bach. Some aspects of my interpretation are readily audible, while others stem from my physical knowledge of music. An embodied analysis such I undertake here may uncover musical meanings apparent only to performer, demonstrating that the score is not work to a performer; nor is score-made-sound work: work includes performer's mobilizing of previously studied skills so to embody, to make real, to make sounding, a set of relationships that are only partly relationships among sounds (Cusick 1994:18). Many feminist scholars have observed that body is too often written out of academic study of music. For instance, Philip Bohlman sees this erasure writ large in musicology's disinclination to study dance (1993:431). Suzanne Cusick's critique of mainstream musicological practice aims to rehabilitate the inextricable presence of body in music--a presence both musicology's and music theory's focus on intentions and texts of composers scrupulously denies (1994:15). Feeling that she is not meant to speak a performer when teaching she has written of her efforts to resolve this apparent disjunction: as a performer, I act on and with what we ordinarily call music with my body; a musicologist I have been formed to act on (and with?) what we ordinarily call music with my mind, and only with my mind (9). Recognizing in act of music-making a resolution of this apparent mind/body split, Cusick argues for a more embodied analytical practice, calling for a theory of musical (18). Elisabeth Le Guin has demonstrated historical and interpretive insights that can be gained from such an embodied analytical practice, using her own performing body to explore music and life of Boccherini (2002; 2006). Her methodology, which she calls carnal musicology, links her experience a performer to eighteenth-century notion of sensibilite and shows how knowledge originating in her sensate body can motivate an interpretation of a piece. In past two decades music scholars using feminist and queer theories have focused attention on musical bodies in their analysis and criticism. Relating performative knowledge of a piece to aspects of music's structure is one such approach. A more common feminist methodology seeks connections between personal identity (the composer's or performer's), and musical structures and/or performance. We can fuse these approaches by thinking about how subjectivity might be inscribed upon a music-making body. For instance, in studying vocal performativity, Cusick (1999) considers how our voices embody (perform) our gender, sex, ethnicity, etc. She hears in timbre of Eddie Vedder's singing an assertion of his heterosexual male American subjectivity. His characteristic snarl, suggesting tightly constricted throat muscles, demonstrates his resistance to discipline of song by physically limiting culture's penetration into innermost spaces of his body; context for this analysis includes her observation that singing is a normative behavior in our culture for women but not for men. In another example of work that connects music and identity through music-making body, Philip Brett relates Schubert's presumed homosexuality to composer's four-hand piano music. …

A genetic screen to identify genes necessary for C. elegans pharynx muscle development

A genetic screen to identify genes necessary for C. elegans pharynx muscle development

Reply to the Letter to the Editor of R. Navarro et al. concerning “Infrahyoid muscle flap for pharyngeal fistulae after cervical spine surgery: a novel approach —report of six cases” (by R.O. Seidl et al., Eur Spine J (2007) 16: 501–505)

Dear Editor, We would like to thank you for your contribution to the discussion and meanwhile take the opportunity to take up a number of points: It is true that closing of injuries to the pharyngeal wall using the sternocleidomastoid muscle (SCM) via the incision, is a technically straightforward method. Nevertheless, pharyngeal defects following surgery to the cervical spine are in most cases located on the anterior part of the pharynx. Even with skilled preparation, the SCM, which must be placed between the pharynx and spine, still remains a rounded muscle bundle. The SCM therefore restricts the pharynx and can thus be an additional factor in triggering swallowing disorders. This is, in our opinion, reflected in the significantly longer period for which feeding tubes remain in place where pharyngeal defects are reconstructed using the SCM. An infrahyoid flap (IHF) is no thicker than the pharynx musculature and barely restricts the pharynx, as is shown by the CT images in our publication. In addition, the superior fascia cervicalis of the IHF, which is included when preparing the IHF, forms a sliding layer between the pharynx and spine. This sliding layer facilitates movement of the pharynx against the spine. We have discussed the necessity of this sliding layer in a previous publication [2]. It represents an additional reason for the reduction in the period for which feeding tubes remain in place. All cervical muscle flaps which are innervated by nerves, which were not damaged in the course of the spinal cord injury further curtail the patient’s already restricted motor possibilities. This applies as much to the SCM as to the IHF. Both muscles play a similar role in breathing, so that this function is equally diminished with both flaps. From the short period for which feeding tubes remained in place as per our results, it can be concluded that the IHF does not restrict swallowing. To date, it has not been possible to establish a link between swallowing disorders following injury to the cervical spine and the degree of damage to the spinal cord or the attached nerves (ansa cervicalis) [1, 3], so that the loss of the IHF on one side is clearly not a factor in the development of a swallowing disorder. In the opinion of the authors, preparation of the IHF presents no particular difficulties for the surgeon. The flap can be prepared via the incision used to access the spine and pharynx. After receiving the necessary training, an experienced surgeon will have no difficulties preparing the ansa cervicalis or the thyroid artery and vein. One of the authors is a neurosurgeon who performs the preparation alone. Should, however, technical problems arise, then interdisciplinary collaboration to the benefit of the patient should be aimed. The significantly shorter period for which feeding tubes remain in place and the associated earlier resumption of oral feeding in our opinion represent significant benefits for the patient and for this reason make the IHF the first choice in the treatment of post-operative pharyngeal defects.

Swallowing before and after tonsillectomy as evaluated by surface electromyography

Surface electromyography (sEMG) was performed on adult patients (n = 40) following tonsillectomy to evaluate recovery by objective means. Evaluated parameters included timing of swallowing and continuous drinking, electric amplitude and graphic patterns of masseter (MS), and measurement of infrahyoid (INF) and submental (SUB) muscles after tonsillectomy and comparison with normative database. The duration of drinking periods showed significant increase among patients; single-swallow durations remained normal. The electric activity of MS and INF muscles was significantly higher among the patients compared with normative database. It took one month until all the EMG data returned to normal. Tonsillectomy affects muscle activity during swallowing by involving additional muscles in deglutition. EMG is a simple reliable method for postoperative evaluation and might contribute to comparative analysis of different tonsillectomy techniques. EMG can be used during pre- and postoperative stages to monitor recovery and functional improvement of throat muscles and deglutition. The reported sEMG method and obtained data might be further used: 1) As an additional tool for comparison of different methods of tonsillectomy (eg, cold vs hot dissection, laser surgery, etc); 2) For further development of objective postsurgical pain assessment; 3) As an additional tool for assessment and development of less traumatic surgical technique; and 4) For monitoring of recovery in difficult cases.

The influence of tonsillitis on oral and throat muscles in adults

Surface electromyography (sEMG) was performed on randomly chosen adults with acute and recurrent tonsillitis to trace changes in muscle activity. Randomized prospective study. Activity of masseter (MS), submental (SUB), and infrahyoid muscles (INF) were examined and statistically analyzed during deglutition being compared to normative databases. For acute tonsillitis, the duration of muscle activity during deglutition was normal with normal amplitude, except for INF muscles. When the acute episode was over, no peculiarities remained. For recurrent tonsillitis, the duration of activity and SUB amplitude remains normal and activity of MS and INF became increased, and this abnormality remained during the remissions. Acute and recurrent tonsillitis affect muscle activity significantly by involving additional muscles (mainly infrahyoid) in swallowing. Acute tonsillitis triggers temporary electric hyperactivity of infrahyoid muscles. Recurrent tonsillitis affects MS and INF even during periods of remission (fixed pathological changes). This data might justify patients' complaints during the period of remission and can be used for comparison purposes to trace possible complications of tonsillitis.

Correlative morphometric and electrochemical measurements of serotonin content in earthworm muscles

Distribution of serotonin (5-HT) content of nervous fibers in both the somatic and the visceral muscle of Eisenia fetida have been investigated using immunocytochemical staining and voltammetric measurements. The somatic muscles in the body wall are richer innervated with serotoninergic fibers than the visceral ones in the pharynx and gizzard. The relative density of immunopositive fibers in the circular muscle layer of the body wall was found to be 2.73% while in the prostomium it was 1.02%. In the case of the muscle in pharynx 1.12% and in gizzard 1.28% density values were found. Differential Pulse Voltammetric (DPV) measurements with carbon fiber electrodes in the above mentioned muscle layers gave 272.5 nA, 135.0 nA, 122.5 nA, 137.5 nA peak heights, respectively. In the statistical analysis T-test was used at a confidence level of 95% ( p < 0.05). DPV current peak ( i p) values reflect clearly the 5-HT concentration differences. Significant correlation was found between the innervation density and the i p values recorded in different areas. The i p values recorded at different times in different locations are determined by instantaneous serotonin concentration of the living tissue. As far as we know this is the first report using in vivo voltammetry investigating serotonin content in earthworm, E. fetida.

Effects of the novel anthelmintic emodepside on the locomotion, egg-laying behaviour and development of Caenorhabditis elegans

Emodepside, a cyclooctadepsipeptide, is a broad-spectrum anthelmintic previously shown to paralyse body wall muscle and pharyngeal muscle in the model nematode Caenorhabditis elegans. We demonstrate that wild-type C. elegans L4 are less sensitive than adults to emodepside in two independent assays of locomotor behaviour: body bend generation on agar (adult IC50 3.7nM, L4 IC50 13.4nM) and thrashing behaviour in liquid (thrashing behaviour as a % of controls after 1h in 10μM emodepside: adults 16%, L4 worms 48%). We also show that continuous exposure of wild-type C. elegans to emodepside throughout the life-cycle from egg onwards, slows worm development, an effect that is emodepside concentration-dependent. The rate of worm-hatching from eggs on agar plates containing emodepside was not significantly different from controls, suggesting that it is development post-hatching rather than hatching itself that is affected by the drug. Emodepside also inhibits wild-type C. elegans egg-laying, with acute exposure to the drug at 500nM resulting in an almost total inhibition within the first hour. However, the rate of egg production was not inhibited and therefore emodepside-treated worms became bloated with eggs, eventually rupturing. This suggests that the effect of emodepside on reproduction is not due to an inhibition of egg production but rather a paralytic effect on the egg-laying muscles. These results, when coupled with previous research, suggest that emodepside interferes with signalling at the neuromuscular junction on the body-wall muscles (Willson et al., 2003), pharynx (Willson et al., 2004) and egg-laying muscles and thus inhibits three important physiological functions: locomotion, feeding and reproduction.

Towards a phylogenetic classification of dendrocoelid freshwater planarians (Platyhelminthes): a morphological and eclectic approach

We explore and review the taxonomic distribution of morphological features that may be used as supporting apomorphies for the monophyletic status of various taxa in future, more comprehensive phylogenetic analyses of the dendrocoelid freshwater planarians and their close relatives. Characters examined are: (i) musculature of the pharynx; (ii) anatomy of the eye; (iii) distribution of testis follicles along the longitudinal axis of the body; (iv) epidermis of the body wall; (v) musculature of the ventral body wall; (vi) presence or absence of a penis papilla; (vii) position of the mouth opening; and (viii) anterior adhesive organ. A phylogenetic hypothesis, in the form of a character state tree, is developed. This hypothesis suggests that the Kenkiidae should be resurrected as a separate family, sharing a sistergroup relationship with the Dendrocoelidae. This sistergroup relationship is supported by the shared presence of an apomorphic anterior adhesive organ. Although the shape of the anterior adhesive organ, both within and between kenkiids and dendrocoelids, may differ considerably between species, they are all constructed according to the same principles. The monophyly of the Kenkiidae is supported by the presence of an apomorphic thickening of the marginal zone of the epidermis and presumably also by the presence of prepharyngeal testes. Within the Kenkiidae, the genus Macrocotyla should be considered as a junior synonym of Kenkia, which is characterized by the presence of an apomorphic ‘planariid pharynx-type 2’. The monophyly of the Dendrocoelidae is suggested by the presence of a dendrocoelid type of pharynx. It is shown that multicellular eye cups with numerous photoreceptor cells are not restricted to the Dugesiidae and the Terricola but are also characteristic for the Dendrocoelidae; the phylogenetic implications of this character state distribution are discussed. It is pointed out that in planarians there may be a relationship between: (i) body size, the size of an eye cup and the number of its constituent pigment cells; and (ii) the size of an eye cup and the number of photoreceptor cells that it contains. Some tentative phylogenetic groups are suggested on the basis of the following presumed apomorphic characters: presence of transverse fibres in the ventral subepidermal musculature, presence of an extra longitudinal muscle layer in the outer pharynx musculature, a mouth opening that has shifted anteriad. It is suggested that the presumed monophyly of the genus Bdellocephala is supported by the apomorphic absence of a penis papilla, combined with a penial lumen provided with many plicae. Wir untersuchen und begutachten die taxonomische Verbreitung morphologischer Merkmale, die man als Apomorphien für die Monophylie verschiedener Taxa in einer zukünftigen umfangreicheren phylogenetischen Analyse der Dendrocoeliden und ihrer nächsten Verwandten heranziehen könnte. Zu diesen untersuchten Merkmalen gehören die Pharynxmuskulatur, die Augen-Anatomie, die Anordnung der Hodenfollikel entlang der Längsachse des Körpers, die Epidermis, die Muskulatur der ventralen Körperwand, das Vorhandensein oder Fehlen einer Penispapille, die Lage der Mundöffnung sowie des vorderen Hartorgans. Eine phylogenetische Hypothese wurde als character state-Stammbaum entwickelt. Hierin wird vorgeschlagen, die Kenkiidae wieder als eigenständige Familie und als Schwestergruppe der Dendrocoelidae zu betrachten. Dieses Schwestergruppen-Verhältnis wird durch den gemeinsamen Besitz eines apomorphen vorderen Haftorgans gestützt. Obwohl sich die Form dieses Organs sowohl innerhalb als auch zwischen Kenkiiden und Dendrocoeliden beträchtlich zwischen den Arten unterscheiden kann, ist es grundsätzlich gleich aufgebaut. Die Monophylie der Kenkiidae wird durch eine als apomorph betrachtete Verdickung des Epidermisrandes und durch das Auftreten praepharyngealer Hoden gestützt. Innerhalb der Kenkiidae sollte die Gattung Macrocotyla als Juniorsynonym von Kenkia angesehen werden, die durch den apomorphen Planarien-Pharynx-Typ 2 charakterisiert ist. Als Beleg für die Monophylie der Dendrocoelidae wird der Dendrocoeliden-Pharynx-Typ vorgeschlagen. Es wird gezeigt, dass vielzellige Augenbecher mit zahlreichen Photorezeptorzellen nicht auf die Dugesiidae und die Terricola beschränkt, sondern auch für die Dendrocoelidae charakteristisch sind; die phylogenetische Bedeutung dieser Merkmalsverteilung wird diskutiert. Es wird hervorgehoben, dass es in den Planarien wahrscheinlich eine Beziehung zwischen (i) Körpergröße, Größe der Augenbecher und Zahl der Photorezeptorzellen ebenso wie (ii) der Größe eines Augenbechers und der Zahl seiner Photorezeptorzellen gibt. Versuchsweise werden einige phylogenetische Gruppierungen auf der Basis der folgenden vermutlich apomorphen Merkmale vorgeschlagen: Vorhandensein transversaler Fasern in der ventralen subepidermalen Muskulatur, Auftreten einer zusätzlichen Längsmuskelschicht in der äußeren Pharynxmuskulatur und eine nach vorn verschobene Mundöffnung. Es wird weiterhin vorgeschlagen, die vermutete Monophylie der Gattung Bdellocephala durch das Fehlen einer Penispapille als Autapomorphie zu stützen, zusammen mit dem Merkmal eines durch viele Falten gekennzeichneten Penislumens.

Specification of theC. elegansMS blastomere by the T-box factor TBX-35

In C. elegans, many mesodermal cell types are made by descendants of the progenitor MS, born at the seven-cell stage of embryonic development. Descendants of MS contribute to body wall muscle and to the posterior half of the pharynx. We have previously shown that MS is specified by the activity of the divergent MED-1,2 GATA factors. We report that the MED-1,2 target gene tbx-35, which encodes a T-box transcription factor, specifies the MS fate. Embryos homozygous for a putative tbx-35-null mutation fail to generate MS-derived pharynx and body muscle, and instead generate ectopic PAL-1-dependent muscle and hypodermis, tissues normally made by the C blastomere. Conversely, overexpression of tbx-35 results in the generation of ectopic pharynx and muscle tissue. The MS and E sister cells are made different by transduction of a Wnt/MAPK/Src pathway signal through the nuclear effector TCF/POP-1. We show that in E, tbx-35 is repressed in a Wnt-dependent manner that does not require activity of TCF/POP-1, suggesting that an additional nuclear Wnt effector functions in E to repress MS development. Genes of the T-box family are known to function in protostomes and deuterostomes in the specification of mesodermal fates. Our results show that this role has been evolutionarily conserved in the early C. elegans embryo, and that a progenitor of multiple tissue types can be specified by a surprisingly simple gene cascade.

Pulmonary rehabilitation in neuromuscular disorders and spinal cord injury

Most patients with impairment of pulmonary function can be differentiated into those who have primarily oxygenation impairment with hypoxia due to predominantly intrinsic lung/airways disease and for whom hypercapnia is an end stage event, and those with lung ventilation impairment on the basis of respiratory muscle weakness for whom hypercapnia causes hypoxia. This distinction is important because, although many patients in the former category have been described to benefit from noninvasive ventilation in the acute care setting, long term use is more controversial. Patients with primarily ventilatory impairment, on the other hand, can benefit from the use of both inspiratory and expiratory muscle aids; and often avoid having any episodes of respiratory failure despite total respiratory muscle paralysis, do not require tracheostomy, and have excellent prognoses with long term home mechanical ventilation. Ventilatory muscle failure is defined by the inability of the inspiratory and expiratory muscles to sustain one’s respiration without resort to ventilator use. Patients with ventilatory muscle failure do not have unlimited breathing tolerance and require ventilatory support and other respiratory muscle aids.Inspiratory and expiratory muscle aids are devices and techniques that involve the manual or mechanical application of forces to the body or intermittent pressure changes to the airway to assist inspiratory or expiratory muscle function. The most important inspiratory aid is to receive air under pressure when one inhales (intermittent positive pressure ventilation or IPPV). The most important expiratory aid is to have a negative pressure (vacuum) applied to the airway via the nose and mouth when one coughs along with a manual thrust to the belly to further increase cough flows. Illness and death in people with generalized weakness, such as patients with neuromuscular disease and high spinal cord injury, is almost always due to respiratory difficulty that occurs because of a weak cough. Breathing (inspiratory), expiratory, and throat (bulbar) muscles are needed for effective coughing. The latter are predominantly the abdominal muscles. Clearing airway secretions can be a continual problem but it most often occurs during chest infections.The following review will describe the most important aspects of pulmonary rehabilitation in patients with muscle weakness /paralysis and its main goals of respiratory muscle substitution to avoid ventilatory failure and promote quality of life in these patients.

Sarcopenia in the Caenorhabditis elegans pharynx correlates with muscle contraction rate over lifespan

In muscles, sarcopenia, the loss of muscle mass, is the major cause of aging-related functional decline and frailty. Several factors are correlated with sarcopenia during aging, including contraction-related cellular injury, oxidative stress, endocrine changes and reduced regenerative potential. However the involvement of these factors has not been experimentally investigated. Here, we report that contraction-related injury may significantly promote the progression of sarcopenia in the pharynx of the nematode, Caenorhabditis elegans, a model of aging in non-regenerative tissues. Both functional and structural declines in the pharynx during aging were significantly delayed in mutants with reduced muscle contraction rates. We also examined the role of bacteria in pharynx muscle decline during aging, as previous studies reported that antimicrobial treatments could extend C. elegans lifespan. Although microbial infection may have enhanced functional decline in the pharynx during aging, it was not the sole cause of decreased pumping rates in old animals. This study identifies contraction-related injury as a factor affecting the initiation and progression of sarcopenia during aging. Further, characterization of the specific types of damage induced by muscle contraction will be helpful for understanding the underlying causes of sarcopenia.

The influence of tonsillitis on oral and throat muscles in children

Surface electromyography (sEMG) studies were performed on 80 children with acute tonsillitis (AT) and 110 children with recurrent tonsillitis (RT), age 4-12 years, to trace sEMG changes of duration and amplitude of muscle activity during swallowing and continuous drinking. Prospective observational study of randomly chosen patients compared to normative database. Timing and amplitude (in muV) of activity of masseter, submental and infrahyoid muscles were evaluated during voluntary single swallows of saliva ("dry" swallow), water swallows, swallows of excessive amount of water (up to 15 ml), and continuous drinking of 50 ml of water. These parameters were measured for two age groups for both conditions: 4-8 and 9-12 years old. The previously established normative database was taken for control. AT presents prolonged duration of swallowing and electric hyperactivity of infrahyoid muscles but this activity returns to normal after recovery. RT affects masseter and infrahyoid muscles even during periods of remission but do not affect duration of swallowing activity. AT and RT in children age 4-12 years affects muscle activity during swallowing significantly by involving additional muscles (mainly infrahyoid) in this process. AT presents temporary electric hyperactivity of infrahyoid muscles. RT affects masseter and infrahyoid muscles even during periods of remission (pathologic changes are fixed). Abnormally high electric activity of masseter and infrahyoid muscles in patients with RT might serve as an additional indicator for tonsillectomy. Surface EMG of swallowing is a simple, non-invasive and reliable method for diagnostic and preoperative evaluation of dysphagia complaints associated with tonsillitis.

The UNC-73/Trio RhoGEF-2 domain is required in separate isoforms for the regulation of pharynx pumping and normal neurotransmission in C. elegans.

In both Caenorhabditis elegans and Drosophila, UNC-73/Trio functions in axon guidance by signaling through the Rac GTPase to regulate cytoskeletal rearrangements necessary for growth cone migrations. Here, we show that the complex C. elegans unc-73 gene encodes at least eight differentially expressed UNC-73 intracellular protein isoforms. Previously reported mutations affecting UNC-73 isoforms encoding the Rac-specific RhoGEF-1 domain cause uncoordinated movement, correlating with defects in axon guidance. Mutations in isoforms encoding the Rho-specific RhoGEF-2 domain, which we describe here, result in L1 stage larval lethality with no associated axon guidance defects. Isoform-specific rescue experiments reveal separate functions for the various RhoGEF-2-containing UNC-73 isoforms, which would not likely be discovered by conventional genetic screening. UNC-73 D1 and D2 appear to function redundantly in pharynx muscle to regulate the rate and strength of pharynx pumping, and in the HSN neurons and vulval muscles to control egg laying. Isoforms C1, C2, E, and F act redundantly within the nervous system to regulate the speed of locomotion. The multiple UNC-73 isoforms containing Rac- and Rho-specific RhoGEF domains therefore have distinct physiological functions. In addition to its previously identified role involving RhoGEF-1 in migrating cells and growth cones, our data indicate that UNC-73 signals through RhoGEF-2 to regulate pharynx and vulva musculature and to modulate synaptic neurotransmission.

Chronic fatigue syndrome: it's tiring not knowing much—an in-depth review for occupational health professionals

Fatigue is an incredibly common symptom in medical settings. In the Office of National Statistics Survey 2000 (1), a degree of limiting fatigue was reported by 27% of working-age adults. Although it is claimed that about three-quarters of these patients in primary care go on to develop chronic symptoms, this is at odds with the reported point prevalence of only up to 3%. The vast majority of this fatigue falls within the 'medically unexplained' (2) category yet does not meet the diagnostic criteria for chronic fatigue syndrome (CFS). Even those that might do are often not diagnosed as such by physicans (3). As Ranjith ((4), this issue) demon- strates, there are several sets of different diagnostic criteria that make this difficult area even more complex. A primary agreement seems to be the requirement for the fatigue to have lasted for 6 months or more and to be associated with a substantial degree of impairment. It is this impairment that is the primary reason for occu- pational health involvement. Further symptoms must co- occur with the fatigue over the 6 month period (impaired memory or concentration, sore throat, tender glands, aching or stiff muscles, post-exertional fatigue, multi-joint pain, unrefreshing sleep and new headaches), although the actual number required fluctuates. Other clinically important physical causes preclude diagnosis, as do underlying serious psychiatric conditions such as schizophrenia. The common co-morbidity with anxiety and depression does not rule out the diagnosis and has complicated research, treatment and policy. A lot of published work covers either less severe conditions or those with shorter duration. These con- ditions receive labels such as 'chronic-fatigue like syndrome' or 'idiopathic chronic fatigue'. A recent review covered work in Holland amongst this group of subjects

Cortico-motoneurone excitability in patients with obstructive sleep apnoea.

A disordered neuromotor control of pharynx muscles may play a role in the genesis of obstructive sleep apnoea syndrome (OSAS). This raises the possibility of a dysfunction of projections descending from the cortex to segmental nuclei. With single pulse transcranial magnetic stimulation (TMS) we studied the physiology of the corticospinal projection to hand muscles in seven OSAS patients. At first, we compared them with nine age- and sex-matched normal controls in the wake state. The only abnormality was a lengthening of the central silent period (P < 0.001). This supports a steady imbalance of motor cortical interneurone activities towards a state of enhanced inhibition. Then we looked at changes of the motor-evoked potential (MEP) size and latency, according to whether patients were awake, or in a non-rapid eye movement (REM) 2 sleep stage, or during a typical apnoea. During non-REM 2 sleep, the average MEP amplitude was significantly (P < 0.05) smaller than in the awake state. The MEP latency was, in turn, significantly longer (P < 0.05). During apnoeas, the MEP size decreased, and the latency increased further (P < 0.05), indicating an extra depression of the cortico-motoneuronal activity. All TMS changes were detected outside the pharyngeal district, suggesting a widespread dysfunction of the cortico-motoneuronal system in the OSAS, which is more evident during apnoeas.

Clinical observation on acupuncture treatment of post-windstroke pseudobulbar palsy

In this research, X-ray photograph and kinescope were applied to observe the whole process of barium swallowing statically and dynamically before and after acupuncture treatment by the radiography of the upper alimentary tract (RART). The observation was made on the objective changes about the functional renovation of contractor muscle of pharynx and epiglottis muscle. Among 36 cases, function of speaking basically recovered in 3 cases, function of swallowing 16 cases, function of expectorating sputum 15 cases, and for function of water drinking 13 cases. The total effective rate: 75.0% for function of speaking, 97.2% for function of swallowing, 75.0% for function of expectorating sputum, 97.2% for function of water drinking.