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1
Deng, Linhong, Nigel J. Fairbank, Darren J. Cole, Jeffrey J. Fredberg, and Geoffrey N. Maksym. "Airway smooth muscle tone modulates mechanically induced cytoskeletal stiffening and remodeling." Journal of Applied Physiology 99, no. 2 (August 2005): 634–41. http://dx.doi.org/10.1152/japplphysiol.00025.2005.
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The application of mechanical stresses to the airway smooth muscle (ASM) cell causes time-dependent cytoskeletal stiffening and remodeling (Deng L, Fairbank NJ, Fabry B, Smith PG, and Maksym GN. Am J Physiol Cell Physiol 287: C440–C448, 2004). We investigated here the extent to which these behaviors are modulated by the state of cell activation (tone). Localized mechanical stress was applied to the ASM cell in culture via oscillating beads (4.5 μm) that were tightly bound to the actin cytoskeleton (CSK). Tone was reduced from baseline level using a panel of relaxant agonists (10−3 M dibutyryl cAMP, 10−4 M forskolin, or 10−6 M formoterol). To assess functional changes, we measured cell stiffness (G′) using optical magnetic twisting cytometry, and to assess structural changes of the CSK we measured actin accumulation in the neighborhood of the bead. Applied mechanical stress caused a twofold increase in G′ at 120 min. After cessation of applied stress, G′ diminished only 24 ± 6% (mean ± SE) at 1 h, leaving substantial residual effects that were largely irreversible. However, applied stress-induced stiffening could be prevented by ablation of tone. Ablation of tone also inhibited the amount of actin accumulation induced by applied mechanical stress ( P < 0.05). Thus the greater the contractile tone, the greater was applied stress-induced CSK stiffening and remodeling. As regards pathobiology of asthma, this suggests a maladaptive positive feedback in which tone potentiates ASM remodeling and stiffening that further increases stress and possibly leads to worsening airway function.
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Kamyk - Wawryszuk, Agnieszka. "Prewerbalne zachowania komunikacyjne dzieci z zespołem Cri du Chat w ocenie rodziców." Interdyscyplinarne Konteksty Pedagogiki Specjalnej, no. 21 (January 7, 2019): 143–66. http://dx.doi.org/10.14746/ikps.2018.21.08.
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Cri du Chat syndrome (CdC) is a rare disease characterized, among others, by decreased muscle tone, microcephaly, and high palate; underdevelopment of the mandible, abnormal structure and laryngeal function (somatic symptoms) and disorders of psychomotor development and intellectual disability (psychomotor symptoms). These children have a varied level of functioning and most of them do not use verbal speech. Describing the problem of preverbal communication behaviors, the following elements were taken into account: the level of behavior in the primary communication, sensory, auditory communication, organization of behavior and signaling needs. The purpose of this article is to describe the pre-verbal behavior of children with Cri du Chat syndrome. The following questions were formulated: What is the level of pre-verbal communication (primary, sensory and auditory) of a child with CdC syndrome? What are the communicative behaviors of the child with the CdC team and at what level of organization? What is the level of signaling your needs by a child with CdC? The preverbal communication behavior of children with the Cri du Chat team presented in the article indicate that they are diverse, ranging from indicating the gesture of what they need, to vocalizing in order to provoke contact with another person. The behavior of the daughter / son indicated by the parents may constitute the basis for the teaching process of preverbal communication.
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Wei, Ning, and Anita T. Layton. "Theoretical assessment of the Ca2+ oscillations in the afferent arteriole smooth muscle cell of the rat kidney." International Journal of Biomathematics 11, no. 03 (April 2018): 1850043. http://dx.doi.org/10.1142/s1793524518500432.
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The afferent arteriole (AA) of rat kidney exhibits the myogenic response, in which the vessel constricts in response to an elevation in blood pressure and dilates in response to a pressure reduction. Additionally, the AA exhibits spontaneous oscillations in vascular tone at physiological luminal pressures. These time-periodic oscillations stem from the dynamic exchange of Ca[Formula: see text] between the cytosol and the sarcoplasmic reticulum, coupled to the stimulation of Ca[Formula: see text]-activated potassium and chloride channels, and to the modulation of voltage-gated L-type Ca[Formula: see text] channels. The effects of physiological factors, including blood pressure and vasoactive substances, on AA vasomotion remain to be well characterized. In this paper, we analyze a mathematical model of Ca[Formula: see text] signaling in an AA smooth muscle cell. The model represents detailed transmembrane ionic transport, intracellular Ca[Formula: see text] dynamics as well as kinetics of nitric oxide (NO) and superoxide (O[Formula: see text]) formation, diffusion and reaction. NO is an important factor in the maintenance of blood pressure and O[Formula: see text] has been shown to contribute significantly to the functional alternations of blood vessels in hypertension. We perform a bifurcation analysis of the model equations to assess the effect of luminal pressure, NO and O[Formula: see text] on the behaviors of limit cycle oscillations.
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Schneider, Johann, Daniel S. Scholz, and Eckart Altenmüller. "Impact of Psychic Traumatization on the Development of Musicians’ Dystonia: Six Exploratory Case Studies." Medical Problems of Performing Artists 36, no. 1 (March 1, 2021): 1–9. http://dx.doi.org/10.21091/mppa.2021.1001.
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OBJECTIVE: Musician’s dystonia represents a special case of focal dystonia. It is described as a task-specific movement disorder which presents itself as muscular incoordination or loss of voluntary fine-motor control of extensively trained movements while a musician is playing the instrument. Several triggering factors have been identified, such as overuse, chronic pain, perfectionism, and anxiety disorders. As a common feature, dysfunctional self-management and stress-coping mechanisms are at the root of the aforementioned behaviors. Based on long-term experience from our musicians’ medicine outpatient clinic, we hypothesized that early psychic or somatic traumatization may be an underlying mechanism and therefore contribute essentially to focal dystonia. METHODS: In a qualitative study, we investigated the role of early traumatization as a potential cause of motor failures, such as musician’s dystonia, employing an episodic interview on a sample of six professional musicians (age 30–57 yrs, 5:1 M:F) suffering from musician’s dystonia. RESULTS: Using grounded theory methodology, we were able to derive one generalized etiological model describing contributing factors in the etiological understanding of focal dystonia from the six case studies. The qualitative interviews clearly revealed that all patients experienced early psychic traumatizations, including violence and parents’ substance abuse. CONCLUSIONS: In this small sample, we theorize that in-depth, early traumatization most probably led to a dysfunctional stress-coping mechanism. We therefore propose in our model that there are two types of motor failures, one linked to stressful experiences, dysfunctional coping behaviors, and increased muscle tone, and one linked to genetic susceptibility of the motor-system without psychological triggering factors.
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Kang, Hyun Gu, and Lewis A. Lipsitz. "Stiffness Control of Balance During Quiet Standing and Dual Task in Older Adults: The MOBILIZE Boston Study." Journal of Neurophysiology 104, no. 6 (December 2010): 3510–17. http://dx.doi.org/10.1152/jn.00820.2009.
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Distractions affect postural control, but this mechanism is not well understood. Diversion of resources during cognitive stress may lead to decreased motor drive and postural muscle tone. This may appear as decreased postural stiffness and increased postural sway amplitude. We hypothesized that dual tasking leads to decreased stiffness and increased sway amplitude. Postural sway (center of pressure; COP) data were used from 724 participants aged 77.9 ± 5.3 yr, a representative sample of community-dwelling older adults, the MOBILIZE Boston Study cohort. Subjects stood barefoot with eyes open for 30 s per trial on a force plate. Five trials were performed each with and without a serial subtractions-by-3 task. Sway data were fit to a damped oscillator inverted pendulum model. Amplitudes (COP and center of mass), mechanical stiffness, and damping of the sway behavior were determined. Sway amplitudes and damping increased with the dual task ( P < 0.001); stiffness decreased only mediolaterally ( P < 0.001). Those with difficulty doing the dual task exhibited larger sway and less damping mediolaterally ( P ≤ 0.001) and an increased stiffness with dual task anteroposteriorly (interaction P = 0.004). Dual task could still independently explain increases in sway ( P < 0.001) after accounting for stiffness changes. Thus the hypothesis was supported only in mediolateral sway. The simple model helped to explain the dual task related increase of sway only mediolaterally. It also elucidated the differential influence of cognitive function on the mechanics of anteroposterior and mediolateral sway behaviors. Dual task may divert the resources necessary for mediolateral postural control, thus leading to falls.
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Kuruma, Akinori, and H. Criss Hartzell. "Bimodal Control of a Ca2+-Activated Cl− Channel by Different Ca2+ Signals." Journal of General Physiology 115, no. 1 (December 28, 1999): 59–80. http://dx.doi.org/10.1085/jgp.115.1.59.
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Ca2+-activated Cl− channels play important roles in a variety of physiological processes, including epithelial secretion, maintenance of smooth muscle tone, and repolarization of the cardiac action potential. It remains unclear, however, exactly how these channels are controlled by Ca2+ and voltage. Excised inside-out patches containing many Ca2+-activated Cl− channels from Xenopus oocytes were used to study channel regulation. The currents were mediated by a single type of Cl− channel that exhibited an anionic selectivity of I− > Br− > Cl− (3.6:1.9:1.0), irrespective of the direction of the current flow or [Ca2+]. However, depending on the amplitude of the Ca2+ signal, this channel exhibited qualitatively different behaviors. At [Ca2+] < 1 μM, the currents activated slowly upon depolarization and deactivated upon hyperpolarization and the steady state current–voltage relationship was strongly outwardly rectifying. At higher [Ca2+], the currents did not rectify and were time independent. This difference in behavior at different [Ca2+] was explained by an apparent voltage-dependent Ca2+ sensitivity of the channel. At +120 mV, the EC50 for channel activation by Ca2+ was approximately fourfold less than at −120 mV (0.9 vs. 4 μM). Thus, at [Ca2+] < 1 μM, inward current was smaller than outward current and the currents were time dependent as a consequence of voltage-dependent changes in Ca2+ binding. The voltage-dependent Ca2+ sensitivity was explained by a kinetic gating scheme in which channel activation was Ca2+ dependent and channel closing was voltage sensitive. This scheme was supported by the observation that deactivation time constants of currents produced by rapid Ca2+ concentration jumps were voltage sensitive, but that the activation time constants were Ca2+ sensitive. The deactivation time constants increased linearly with the log of membrane potential. The qualitatively different behaviors of this channel in response to different Ca2+ concentrations adds a new dimension to Ca2+ signaling: the same channel can mediate either excitatory or inhibitory responses, depending on the amplitude of the cellular Ca2+ signal.
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Stenmark, Kurt R., Neil Davie, Maria Frid, Evgenia Gerasimovskaya, and Mita Das. "Role of the Adventitia in Pulmonary Vascular Remodeling." Physiology 21, no. 2 (April 2006): 134–45. http://dx.doi.org/10.1152/physiol.00053.2005.
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An increasing volume of experimental data indicates that the adventitial fibroblast, in both the pulmonary and systemic circulations, is a critical regulator of vascular wall function in health and disease. A rapidly emerging concept is that the vascular adventitia acts as biological processing center for the retrieval, integration, storage, and release of key regulators of vessel wall function. In response to stress or injury, resident adventitial cells can be activated and reprogrammed to exhibit different functional and structural behaviors. In fact, under certain conditions, the adventitial compartment may be considered the principal injury-sensing tissue of the vessel wall. In response to vascular stresses such as overdistension and hypoxia, the adventitial fibroblast is activated and undergoes phenotypic changes, which include proliferation, differentiation, upregulation of contractile and extracellular matrix proteins, and release of factors that directly affect medial smooth muscle cell tone and growth and that stimulate recruitment of inflammatory and progenitor cells to the vessel wall. Each of these changes in fibroblast phenotype modulates either directly or indirectly changes in overall vascular function and structure. The purpose of this review is to present the current evidence demonstrating that the adventitial fibroblast acts as a key regulator of pulmonary vascular function and structure from the “outside-in.”
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Del Pozzo, Jill, Erica F. Weiss, Diana Bronshteyn, David M. Masur, John J. McGinley, and Ronda F. Facchini. "A-41 Not Just a “Clumsy” Kid: A Case Study of Developmental Coordination Disorder." Archives of Clinical Neuropsychology 36, no. 6 (August 30, 2021): 1082. http://dx.doi.org/10.1093/arclin/acab062.59.
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Abstract Objective Developmental Discoordination Disorder (DCD) is an often overlooked and seldom diagnosed neurodevelopmental condition marked by impairments in motor skills. Lacking identifiable medical or neurological etiology, children with DCD often have preserved intellectual abilities. Comorbidity is common, including ADHD and specific learning disability. Despite extensive evidence of significant impact on daily activities and academics due to differences in motor behaviors, DCD difficulties are regularly treated as behavioral problems. Method Neuropsychological evaluation of an 8-year-old boy with a possible reading delay and inability to perform some age-appropriate academic and self-care tasks. Results Average overall ability with very strong verbal performances; intact visual perceptual processing, memory, and non-written language. Academics are within expected range, although graphomotor weakness impacted academic performances on tasks with written demands. Patient appeared clumsy and awkward with low muscle tone, poor balance, and difficulty learning new motor skills. Impaired fine motor control, handwriting, gait, gross motor skills, motor planning, coordination, and oromotor weakness as well as inferior verbal language abilities were evident. Impulsivity, inattention, poor planning, and poor self-monitoring were also evident. Conclusions DCD is evidenced by impairment in fine and gross motor skills, oromotor skills, motor planning, energy, and coordination with clear discrepancy between motor abilities and abilities in other areas, specifically language. In our case, DCD features were overlooked despite wide ranging impact. ADHD and SLD with impairment in written expression were concurrent. This case highlights the need for greater appreciation of DCD so that children can benefit from early detection and intervention considering the life-long implications of the disorder.
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Sampallo Pedroza, Rosa Mercedes, Luisa Fernanda Cardona Lopez, and Karen Eliana Ramirez Gomez. "Description of oral-motor development from birth to six years of age." Revista de la Facultad de Medicina 62, no. 4 (May 7, 2015): 593–604. http://dx.doi.org/10.15446/revfacmed.v62n4.45211.
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<p>This document seeks to present bibliometric research into<br />characterizing the behaviors of each of the stomatognathic<br />functions of a child based on developmental age and expected<br />development until the age of six. The investigation collected<br />the information provided in scientific literature regarding the<br />development of oral-motor postural patterns, environmental<br />influences, sensitivity, tone, muscle strength, use of feeding<br />tools, anatomy, physiology, and the neurology of the anatomical<br />structures of the stomatognathic system. As a result, the major<br />milestones of oromotor development from birth to the age of six<br />are described in this document. Also, a more detailed manual<br />was written to be used by Speech-Language Pathologists. The<br />research concludes that oral motor patterns emerge according<br />to the maturation and function of the different stomatognathic<br />structures. It is of prime importance for Speech-Language<br />Pathologists to be experts in normal oromotor development in<br />order to provide the best professional services when treating<br />children in need of feeding, sucking and dysphagia therapy.</p>
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Nakayama, Natsuki, Masahiko Miyachi, Koji Tamakoshi, Toshio Hayashi, Koji Negi, Koji Watanabe, and Makoto Hirai. "Decreased continuous sitting time increases heart rate variability in patients with cardiovascular risk factors." PLOS ONE 16, no. 6 (June 16, 2021): e0253399. http://dx.doi.org/10.1371/journal.pone.0253399.
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Aim The purpose of the present study was to elucidate the relationship between high-frequency heart rate variability (HF HRV) and continuous daytime sitting time in patients with cardiovascular risk factors such as mild hypertension and/or stable angina pectoris. Background Decreased HF HRV precedes the progression and worsening of cardiovascular diseases. Continuous sitting behavior is a major risk factor for developing metabolic syndrome and is associated with cardiovascular disease, diabetes mellitus, renal failure, sarcopenia and osteoporosis. Risk factors for cardiovascular disease can be affected by continuous daytime sitting behaviors. Design The present study design was a post-hoc comparison. Methods Patients treated at two different primary care clinics from 2014 to 2018 were enrolled in this study (n = 53). We assessed HF HRV and continuous sitting time using 24-hour Holter electrocardiography and an activity meter at baseline and 6 months. HF HRV was calculated during sleep. Results Sitting time had decreased in 22 patients (decreased group) and increased in 31 patients (increased group) after 6 months. The mean patient ages were 73.1 and 72.0 years in the decreased and increased sitting time groups, respectively (p = 0.503). HF HRV during sleep had increased after 6 months in the decreased sitting time group. Compared with the increased group, the decreased group showed significantly higher HF HRV during sleep after 6 months by two-way repeated-measures ANOVA after adjustment for age, sex and change in activity (p = 0.045). Conclusion These results suggest that a decrease in sitting time might induce parasympathetic activity during sleep. Therefore, reducing continuous sitting time during the day might contribute, in part, to improving the prognosis of patients with cardiovascular risk factors not only by avoiding muscle loss but also by providing positive influences on parasympathetic tone during sleep.
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Schwarz, Peter B., and John H. Peever. "Dopamine triggers skeletal muscle tone by activating D1-like receptors on somatic motoneurons." Journal of Neurophysiology 106, no. 3 (September 2011): 1299–309. http://dx.doi.org/10.1152/jn.00230.2011.
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The dopamine system plays an integral role in motor physiology. Dopamine controls movement by modulation of higher-order motor centers (e.g., basal ganglia) but may also regulate movement by directly controlling motoneuron function. Even though dopamine cells synapse onto motoneurons, which themselves express dopamine receptors, it is unknown whether dopamine modulates skeletal muscle activity. Therefore, we aimed to determine whether changes in dopaminergic neurotransmission at a somatic motor pool affect motor outflow to skeletal muscles. We used microinjection, neuropharmacology, electrophysiology, and histology to determine whether manipulation of D1- and D2-like receptors on trigeminal motoneurons affects masseter and/or tensor palatini muscle tone in anesthetized rats. We found that apomorphine (a dopamine analog) activated trigeminal motoneurons and triggered a potent increase in both masseter and tensor palatini tone. This excitatory effect is mediated by D1-like receptors because specific D1-like receptor activation strengthened muscle tone and blockade of these receptors prevented dopamine-driven activation of motoneurons. Blockade of D1-like receptors alone had no detectable effect on basal masseter/tensor palatini tone, indicating the absence of a functional dopamine drive onto trigeminal motoneurons, at least during isoflurane anesthesia. Finally, we showed that D2-like receptors do not affect either trigeminal motoneuron function or masseter/tensor palatini muscle tone. Our results provide the first demonstration that dopamine can directly control movement by manipulating somatic motoneuron behavior and skeletal muscle tone.
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Lai, Yuan-Yang, Tohru Kodama, Elizabeth Schenkel, and Jerome M. Siegel. "Behavioral Response and Transmitter Release During Atonia Elicited by Medial Medullary Stimulation." Journal of Neurophysiology 104, no. 4 (October 2010): 2024–33. http://dx.doi.org/10.1152/jn.00528.2010.
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Activation of the medial medulla is responsible for rapid eye movement (REM) sleep atonia and cataplexy. Dysfunction can cause REM sleep behavior disorder and other motor pathologies. Here we report the behavioral effects of stimulation of the nucleus gigantocellularis (NGC) and nucleus magnocellularis (NMC) in unrestrained cats. In waking, 62% of the medial medullary stimulation sites suppressed muscle tone. In contrast, stimulation at all sites, including sites where stimulation produced no change or increased muscle tone in waking, produced decreased muscle tone during slow-wave sleep. In the decerebrate cat electrical stimulation of the NGC increased glycine and decreased norepinephrine (NE) release in the lumbar ventral horn, with no change in γ-aminobutyric acid (GABA) or serotonin (5-HT) release. Stimulation of the NMC increased both glycine and GABA release and also decreased both NE and 5-HT release in the ventral horn. Glutamate levels in the ventral horn were not changed by either NGC or NMC stimulation. We conclude that NGC and NMC play neurochemically distinct but synergistic roles in the modulation of motor activity across the sleep–wake cycle via a combination of increased release of glycine and GABA and decreased release of 5-HT and NE. Stimulation of the medial medulla that elicited muscle tone suppression also triggered rapid eye movements, but never produced the phasic twitches that characterize REM sleep, indicating that the twitching and rapid eye movement generators of REM sleep have separate brain stem substrates.
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Amano, Satoru, Takashi Takebayashi, Keisuke Hanada, Atsushi Umeji, Kohei Marumoto, Keiko Furukawa, and Kazuhisa Domen. "Constraint-Induced Movement Therapy After Injection of Botulinum Toxin Type A for a Patient With Chronic Stroke: One-Year Follow-up Case Report." Physical Therapy 95, no. 7 (July 1, 2015): 1039–45. http://dx.doi.org/10.2522/ptj.20140329.
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Background and Purpose Spasticity, an aspect of upper motor neuron syndrome, is a widespread problem in patients with stroke. To date, no study has reported the long-term (up to 1 year) outcomes of botulinum toxin (BTX) injection in combination with constraint-induced movement therapy in patients with chronic stroke. In this case report, the long-term (1 year) effects of the combination of BTX type A injection and constraint-induced movement therapy on spasticity and arm function in a patient with chronic stroke and arm paresis are described. Case Description The patient was a 66-year-old man who had had an infarction in the right posterior limb of the internal capsule 4 years before the intervention. At screening, the patient was not able to voluntarily extend his interphalangeal or metacarpophalangeal joints beyond the 10 degrees required for constraint-induced movement therapy. From 12 days after BTX type A injection, the patient received 5 hours of constraint-induced movement therapy for 10 weekdays. Outcomes All outcome measures (Modified Ashworth Scale, Fugl-Meyer Assessment, Action Research Arm Test, and amount of use scale of the Motor Activity Log) improved substantially over the 1-year period (before intervention to 1 year after intervention). Repeat BTX type A injections were not necessary because muscle tone and arm function did not worsen during the observation period. Discussion The improved arm function may have reflected improvements in volitional movements and coordination or speed of movements in the paretic arm as a result of a reduction in spasticity, a reduction of learned nonuse behaviors, or use-dependent plasticity after the combination of BTX type A injection and constraint-induced movement therapy. In addition, the possibility of an influence of the passage of time or the Hawthorne effect cannot be ruled out. If this approach proves useful in future controlled studies, it may reduce the rising medical costs of the treatment of stroke.
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Ysunza, Antonio, and Maria C. Vazquez. "Velopharyngeal Sphincter Physiology in Deaf Individuals." Cleft Palate-Craniofacial Journal 30, no. 2 (March 1993): 141–43. http://dx.doi.org/10.1597/1545-1569_1993_030_0141_vspidi_2.3.co_2.
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Fifty-three deaf subjects with a history of prelingual profound bilateral sensorineural hearing loss, similar language habilitation with hearing aids, and normal velopharyngeal structures underwent a study protocol including speech evaluation, behavioral pure-tone audiometry, videonasopharyngoscopy, multiview videofluoroscopy, and electromyography of the velopharyngeal muscles. Subjects were divided into two groups: the first group included 13 subjects with normal nasal resonance or mild hypernasality (four normals and nine with mild hypernasality); the second group had subjects with severe hypernasality and severe articulation deficits. Pure-tone thresholds, velopharyngeal closure patterns, and electromyographic activity of velopharyngeal muscles were similar for both groups of subjects. However, in subjects with severe hypernasality, despite normal muscle activity as observed by electromyography, velopharyngeal valving activity lacked rhythm and strength during speech. It is concluded that deaf subjects may present a functional disorder of the velopharyngeal sphincter related to absence of auditory regulation during phonation. Visual biofeedback using videonasopharyngoscopy may be useful for treating this disorder.
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Salvoni, Alexander D'Alvia, Talita Fakhouri Salvoni, Leonardo Silva Gomes Kamezawa, José Benedito De Oliveira Amorim, and Clóvis Pagani. "Botulinum toxin for modulating the muscle strength of patients rehabilitated with zygomatic implants." Brazilian Dental Science 22, no. 2 (April 30, 2019): 220–27. http://dx.doi.org/10.14295/bds.2019.v22i2.1657.
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Objective: To measure the intensity of muscle strength and electrical activity of masseter and anterior temporal muscles based on BTX-A therapy in patients rehabilitated with total prostheses on zygomatic implants. Material and Methods: The object of the study was a sample of 20 individuals subjected to zygomatic implant surgery and rehabilitated with implant-supported prostheses, in order to obtain electromyographic data using an eight-channel module (EMG System do Brasil). The data were collected for three consecutive months: prior to the application (single dose) of BTX-A (30 U/ masseter muscle; 10 U/temporal muscle) and after 30 and 90 days of therapeutic treatment. Result: All muscle groups studied showed reduction of muscle electrical activity during voluntary contraction after 30 days of treatment (around 47%) (p < 0.001), which progressively reverted after 90 days of treatment. The anterior temporal muscles presented similar motor behavior, with activity reduction of 39% (p < 0.05). There was a reduction of 17.68% (p < 0.05) in mandibular force and an increase of 14.22% (p < 0.05) in mouth opening after 30 days of BTX-A administration. Conclusions: The results suggest that BTX-A significantly reduces muscle activity, in either the recruitment of motor units or muscle tone, in the first three months of therapeutic treatment. This therapy may also be useful as a preventive method for the failure of zygomatic implant-supported prostheses.KeywordsElectromyography; Dental implants; Prostheses on implants; Botulinum toxin.Keywords: Electromyogra phy; Dental implants; Prostheses on implants; Botulinum toxin.
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Herdmann, J., P. Enck, P. Zacchi-Deutschbein, and U. Ostermann. "Speed and pressure characteristics of external anal sphincter contractions." American Journal of Physiology-Gastrointestinal and Liver Physiology 269, no. 2 (August 1, 1995): G225—G231. http://dx.doi.org/10.1152/ajpgi.1995.269.2.g225.
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The principle of isochronism reflects constant contraction time for varying strengths of muscle contraction. This principle was studied for the innervation of the pelvic floor in humans using motor-evoked potentials (MEPs) and evoked pressure curves (EPCs) from the external anal sphincter muscle (EAS). MEPs and EPCs were simultaneously recorded after transcranial magnetic stimulation of the motor cortex. Voluntary contractions were also studied. Contraction times of the EAS were significantly longer in voluntary contractions (mean, 237 ms) than in EPCs (mean, 90 ms). Depending on either mode of contraction, contraction times varied only slightly despite a wide range of contraction strengths. It is shown that the contractile behavior of the EAS is a function of slow- and fast-twitch muscle fiber distribution and that the principle of isochronism governs motor performance not only of limb muscles but also of the EAS. There exists a unique optimal working range of each muscle to meet its individual function. Disturbance of this principle results in a less efficient contraction with either inappropriate basic tone or disturbed reflex activation in the EAS. Both are possible causes of incontinence.
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McFARLANE, I. D., D. GRAFF, and C. J. P. GRIMMELIKHUIJZEN. "Excitatory Actions of Antho-RFamide, An Anthozoan Neuropeptide, on Muscles and Conducting Systems in the Sea Anemone Calliactis Parasitica." Journal of Experimental Biology 133, no. 1 (November 1, 1987): 157–68. http://dx.doi.org/10.1242/jeb.133.1.157.
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In the sea anemone Calliactis parasitica endodermal application of the anthozoan neuropeptide Antho-RFamide (<Glu-Gly-Arg-Phe-amide), at a concentration of 10−6 or 10−7moll−1, caused a long-lasting increase in tone, contraction frequency and contraction amplitude in several slow muscle groups but had no effect on contractions in fast muscles. The effects were investigated further in isolated muscle preparations. Ectodermal application to whole animals had no effect on muscle contractions. Both ectodermal and endodermal application, at 10−7moll−1, raised electrical activity in an ectodermal conduction system, the SSI, but had no effect on an endodermal conduction system, the SS2. Electrical activity in the SS2 was increased by application at 10−6moll−1 to the endoderm but not to the ectoderm. The peptide had no effect on the through-conducting nerve net. It is concluded that contractions evoked by Antho-RFamide may be partly due to neuronal activity, but probably also involve direct excitation of the muscles. The diverse excitatory actions of Antho-RFamide suggest that it may be a neurotransmitter or neuromodulator in sea anemones.
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Charous, Steven J., Jeffery M. Hotaling, Bridget D. Burgess, Joshua M. Sappington, James Park, Grant Turek, and Eileen M. Foecking. "Muscle-Nerve-Muscle Grafting for Facial Reanimation in Rats." Annals of Otology, Rhinology & Laryngology 126, no. 4 (January 10, 2017): 261–67. http://dx.doi.org/10.1177/0003489416686587.
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Objective: Facial paralysis is a devastating condition leaving patients with a myriad of aesthetic and functional consequences. Muscle-nerve-muscle (MNM) neurotization is a reinnervation technique that involves implanting an autogenous nerve graft as a conduit between an innervated “donor” muscle and a denervated “recipient” muscle. We investigated the use of MNM reinnervation, alone or in combination with electrical stimulation (ES) and testosterone propionate (TP) in comparison to nerve reanastomosis (RE), on functional recovery following rat facial nerve injury. Methods: Thirty-one male, Sprague-Dawley rats were assigned to groups: no graft (control), MNM grafting alone (MNM), MNM grafting with ES and TP (MNM+ES+TP), or RE. Harvested right facial nerve branches were used as the MNM graft. Functional recovery was assessed by behavioral observations and electromyographic recordings. Results: The MNM grafting improved muscle tone and vibrissae movement. The ES+TP treatment further enhanced muscle tone as well as reduced recovery time for coordinated movement in a manner that is comparable to those of RE. Electromyographic recordings demonstrated electrical conductance across all MNM grafts. Conclusion: These data have important implications for patients with unilateral paralysis from facial or laryngeal nerve injury, particularly those who are not candidates for nerve reanastomosis.
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Mayer, G., K. Kesper, and K. Stiasny-Kolster. "28. Quantification of muscle tone in patients with REM sleep behavior disorder." Clinical Neurophysiology 120, no. 1 (January 2009): e15-e16. http://dx.doi.org/10.1016/j.clinph.2008.07.029.
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Russo, AJ. "Decreased Mitogen Inducible Gene 6 (MIG-6) Associated with Symptom Severity in Children with Autism." Biomarker Insights 9 (January 2014): BMI.S15218. http://dx.doi.org/10.4137/bmi.s15218.
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Background Individuals with autism spectrum disorders (ASDs) demonstrate impairment in social interactions and problems in verbal and nonverbal communication. Autism spectrum disorders are thought to affect 1 in 88 children in the US. Recent research has shown that epidermal growth factor receptor (EGFR) activation is associated with nerve cell development and repair. Mitogen inducible gene 6 (MIG-6) is a 58-kDa non-kinase scaffolding adaptor protein consisting of 462 amino-acids, which has been shown to be a negative feedback regulator of EGFR and Met receptor tyrosine kinase (RTK) signaling. Subjects and Methods In this study, we determined plasma levels of MIG-6, which suppresses the EGFR RTK pathway in autistic children, and compared MIG-6 levels with the EGFR ligand, epidermal growth factor (EGF), and the cMET ligand, hepatocyte growth factor (HGF). MIG-6 levels were also compared to the symptom severity of 19 different autistic behaviors. Plasma MIG-6 concentration was measured in 40 autistic children and 39 neurotypical, age, and gender similar controls using an enzyme linked immunosorbent assay (ELISA). Plasma MIG-6 levels were compared to putative biomarkers known to be associated with EGFR and cMET and severity levels of 19 autism related symptoms [awareness, expressive language, receptive language, (conversational) pragmatic language, focus/attention, hyperactivity, impulsivity, perseveration, fine motor skills, gross motor skills, hypotonia (low muscle tone), tip toeing, rocking/pacing, stimming, obsessions/fixations, eye contact, sound sensitivity, light sensitivity, and tactile sensitivity]. Results In this study, we found that plasma MIG-6 levels in autistic children (182.41 ±24.3 pg/ml) were significantly lower than neurotypical controls (1779.76 ± 352.5; P = 1.76E − 5). Decreased MIG-6 levels correlated with serotonin, dopamine, Tumor necrosis factor alpha (TNF-alpha), and urokinase receptor (uPAR) concentration, but not with other tested putative biomarkers. MIG-6 levels also correlated significantly with severity of expressive language, receptive language, tip toeing, rocking/pacing, and hand flapping/stimming. Conclusions These results suggest a relationship between decreased plasma MIG-6 levels, biomarkers associated with the EGFR pathway, and symptom severity in autism. A strong correlation between plasma MIG-6 and dopamine and serotonin levels suggest that decreased MIG-6 levels may be associated with abnormal neurotransmitter synthesis and/or action. A strong correlation between MIG-6 and uPAR and the inflammatory marker TNF-alpha suggests that low MIG-6 levels may be associated with the HGF/Met signaling pathway, as well as inflammation in autistic children.
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Gauvin, David V., Zachary J. Zimmermann, Jill A. Dalton, Theodore J. Baird, and Mary-Jeanne Kallman. "CNS Safety Screening Under ICH S7A Guidelines Requires Observations of Multiple Behavioral Units to Assess Motor Function." International Journal of Toxicology 38, no. 5 (August 30, 2019): 339–56. http://dx.doi.org/10.1177/1091581819864836.
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In the adoption of behavior as a critical end point in safety pharmacology and neurotoxicity screening, federal regulatory agencies have shifted the predominating scientific perspective from pharmacology back to the experimental analysis of behavior (psychology). Nowhere is this more evident than in tier I safety assessment of the central nervous system (CNS). The CNS and peripheral nervous system have multiple behavioral units of general activity. A complete picture of the motor control neural pathways cannot be measured by any one single approach. The CNS safety protocols under International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use S7A are required to be conducted in accordance with Good Laboratory Practices by trained technical staff. The CNS safety assessments necessitate the inclusion of a thorough and detailed behavioral analysis of home cage activity, the response to handling, and transportation to and observations within an open-field apparatus with ancillary measures of basal muscle tone, muscle strength, and tremor in a functional observation battery, as well as quantitative measurements of 3-dimensional activity in an automated photobeam arena. Cost-cutting initiatives or a radical application of the “reduce use” principle of the 3 Rs only jeopardize the spirit, intent, and predictive validity of tier I safety testing assays dictated by current drug safety guidelines.
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Brayden, Joseph E., Yao Li, and Matthew J. Tavares. "Purinergic Receptors Regulate Myogenic Tone in Cerebral Parenchymal Arterioles." Journal of Cerebral Blood Flow & Metabolism 33, no. 2 (November 21, 2012): 293–99. http://dx.doi.org/10.1038/jcbfm.2012.169.
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Myogenic tone is a fundamental aspect of vascular behavior in resistance arteries. This contractile response to changes in intravascular pressure is critically involved in blood flow autoregulation in tissues such as the brain, kidneys, and heart. Myogenic tone also helps regulate precapillary pressure and provides a level of background tone upon which vasodilator stimuli act to increase tissue perfusion when appropriate. Despite the importance of these processes in the brain, little is known about the mechanisms involved in control of myogenic tone in the cerebral microcirculation. Here, we report that pharmacological inhibition of P2Y4 and P2Y6 pyrimidine receptors nearly abolished myogenic tone in cerebral parenchymal arterioles (PAs). Molecular suppression of either P2Y4 or P2Y6 receptors using antisense oligodeoxynucleotides reduced myogenic tone by 44% ± 8% and 45% ± 7%, respectively. These results indicate that both receptor isoforms are activated by increased intravascular pressure, which enhances the activity of voltage-dependent calcium channels and increases myogenic tone in PAs. Enhancement or inhibition of ectonucleotidase activity had no effect on parenchymal arteriolar myogenic tone, indicating that this response is not mediated by local release of nucleotides, but rather may involve direct mechanical activation of P2Y receptors in the smooth muscle cells.
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Matson, Johnny L., Timothy Dempsey, and Jonathan Wilkins. "Rett syndrome in adults with severe intellectual disability: Exploration of behavioral characteristics." European Psychiatry 23, no. 6 (September 2008): 460–65. http://dx.doi.org/10.1016/j.eurpsy.2007.11.008.
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AbstractRett syndrome is a genetically linked form of autism spectrum disorder (ASD) accompanied by intellectual disability (ID). The disorder is also characterized by cardiorespiratory dysregulation, disturbance in muscle tone, reduced brain growth and scoliosis. Over 300 studies have been published on the disorder, most of which has focused on identification of causative factors, which appears to be the result of mutations of gene MECP2. Rarely have adults with Rett syndrome been studied, and behavioral characteristics in these individuals are largely unknown. The present study aimed to extend what little is known about behavioral characteristics of Rett syndrome in adults, with particular emphasis on social, communicative, and adaptive behavior. Rett syndrome adults with severe ID were matched to autistic adults with ID and ID only controls. The implications of these data for more fully describing and diagnosing the condition in adults are discussed.
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Porter, Verna, and Alon Avidan. "Clinical Overview of REM Sleep Behavior Disorder." Seminars in Neurology 37, no. 04 (August 2017): 461–70. http://dx.doi.org/10.1055/s-0037-1605595.
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AbstractRapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by loss of muscle atonia during REM sleep that allows motor responses to dream content. Patients display patterns of unusual, complex, and even violent motor activities. There is a high risk for harm to the patients or their bedpartners. REM sleep behavior disorder is more likely to occur in synucleinopathies such as Parkinson's disease, Lewy body dementia, and multiple system atrophy and may precede clinical manifestations by decades. In secondary RBD, brainstem centers involved in muscle atonia during REM are disrupted. These conditions include multiple sclerosis, cerebral vascular accidents, and brainstem tumors. The acute onset of RBD may associate with the use of antidepressants and acute withdrawal from alcohol. The diagnosis of RBD should be confirmed by polysomnography utilizing multiple-limb electromyography and synchronized digital video monitoring and demonstrate elevation of muscle tone during REM sleep along with dream enactment behavior. The differential diagnosis includes sleepwalking, nocturnal seizures, sleep apnea, and periodic limb movement disorder. Management focuses on maximizing safety, use of clonazepam/melatonin, and discussion of prognosis with patients.
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Gallasch, Eugen, Thomas Kenner, and Inessa Kozlovskaya. "Microvibration as a Function of Muscle Tone Studied in Microgravity." Naturwissenschaften 85, no. 1 (January 1998): 28–30. http://dx.doi.org/10.1007/s001140050446.
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Jackson, P. A., and B. R. Duling. "Myogenic response and wall mechanics of arterioles." American Journal of Physiology-Heart and Circulatory Physiology 257, no. 4 (October 1, 1989): H1147—H1155. http://dx.doi.org/10.1152/ajpheart.1989.257.4.h1147.
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The magnitude of the arteriolar response to altered intraluminal pressure was assessed in isolated, cannulated vessels of the hamster cheek pouch. Microvessels were studied during various levels of smooth muscle activation, either occurring spontaneously, or resulting from the application of exogenous agonists including potassium (35 or 70 mM) and phenylephrine (1.25 or 2.50 x 10(-6) M). Diameter-pressure curves were obtained by lowering intraluminal pressure from 60 to 0 mmHg in seven steps at 3-min intervals. At an intraluminal pressure of 40 mmHg, spontaneous tone produced an average constriction to 34 +/- 2% of the maximum diameter. Step reductions in pressure typically led to reductions in the level of activation of the muscle, which resulted in a net dilation over a significant pressure range. This “myogenic response” was more effective in modifying spontaneous tone than in modifying exogenous tone. In fact, the data suggest that reduction of the intraluminal pressure to zero can result in complete inactivation of spontaneous tone. Complete inactivation was not observed when contractions were induced by exogenous agonists, however. The magnitude of the myogenic response in arterioles was consistent with a role in autoregulation, which is 2.5-fold greater than that previously reported for small arteries. The data demonstrate that in the analysis of the mechanics of submaximally activated blood vessels one must include considerations of two phenomenon: the classical stress-length behavior as determined under conditions of maximal activation, and a superimposed modification of the activation level induced by stress- or length-dependent processes. Furthermore, the findings indicate substantial differences in response when tone is spontaneous compared with the case when tone is induced by exogenous agonists.
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Kelly, Vanessa J., Nathan J. Brown, Scott A. Sands, Brigitte M. Borg, Gregory G. King, and Bruce R. Thompson. "Effect of airway smooth muscle tone on airway distensibility measured by the forced oscillation technique in adults with asthma." Journal of Applied Physiology 112, no. 9 (May 1, 2012): 1494–503. http://dx.doi.org/10.1152/japplphysiol.01259.2011.
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Airway distensibility appears to be unaffected by airway smooth muscle (ASM) tone, despite the influence of ASM tone on the airway diameter-pressure relationship. This discrepancy may be because the greatest effect of ASM tone on airway diameter-pressure behavior occurs at low transpulmonary pressures, i.e., low lung volumes, which has not been investigated. Our study aimed to determine the contribution of ASM tone to airway distensibility, as assessed via the forced oscillation technique (FOT), across all lung volumes with a specific focus on low lung volumes. We also investigated the accompanying influence of ASM tone on peripheral airway closure and heterogeneity inferred from the reactance versus lung volume relationship. Respiratory system conductance and reactance were measured using FOT across the entire lung volume range in 22 asthma subjects and 19 healthy controls before and after bronchodilator. Airway distensibility (slope of conductance vs. lung volume) was calculated at residual volume (RV), functional residual capacity (FRC), and total lung capacity. At baseline, airway distensibility was significantly lower in subjects with asthma at all lung volumes. After bronchodilator, distensibility significantly increased at RV (64.8%, P < 0.001) and at FRC (61.8%, P < 0.01) in subjects with asthma but not in control subjects. The increased distensibility at RV and FRC in asthma were not associated with the accompanying changes in the reactance versus lung volume relationship. Our findings demonstrate that, at low lung volumes, ASM tone reduces airway distensibility in adults with asthma, independent of changes in airway closure and heterogeneity.
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Fernandes, L. B., K. Stuart-Smith, T. L. Croxton, and C. A. Hirshman. "Role of Ca2+ entry in the modulation of airway tone by hypoxia." American Journal of Physiology-Lung Cellular and Molecular Physiology 264, no. 3 (March 1, 1993): L284—L289. http://dx.doi.org/10.1152/ajplung.1993.264.3.l284.
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To evaluate the cellular mechanisms involved in hypoxic relaxation of airway smooth muscle, we investigated the effects of hypoxia on the behavior of third- and fourth-order porcine bronchial rings contracted with either carbachol or KCl. In one series of experiments, hypoxia (95% N2-5% CO2) was imposed and rings were then exposed to increasing concentrations of carbachol or KCl. In separate experiments, rings were first contracted with carbachol (10(-6) M) or KCl (40 mM) and were then exposed to solutions bubbled with decreasing concentrations of O2. The CO2 concentration was maintained constant at 5% in all experiments. The initial magnitude of KCl-induced but not carbachol-induced contractions was profoundly reduced by 95% N2-5% CO2. The sensitivity of the airway to carbachol was unchanged. In rings precontracted with either carbachol or KCl, hypoxia caused similar losses of airway smooth muscle tone in a reversible and concentration-dependent manner. The effects of hypoxia were independent of the presence of an intact epithelium and were not inhibited by the cyclooxygenase inhibitor indomethacin (5 microM), the soluble guanylate cyclase inhibitor methylene blue (50 microM), or the beta-adrenoceptor antagonist propranolol (1 microM). The impairment by hypoxia of the initiation phase of KCl-induced contractions and of the maintenance phase of both KCl- and carbachol-induced contractions, but not the initiation phase of carbachol-induced contractions, suggests that changes in O2 tension modulate airway tone by altering the entry of extracellular calcium into the airway smooth muscle.
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Winarti, Tri. "RESPON NYERI PADA NEONATUS PASKA PENGAMBILAN DARAH SETELAH DIBEDONG DI RUANG NEONATUS RSUD NGUDI WALUYO WLINGI." Jurnal Ners dan Kebidanan (Journal of Ners and Midwifery) 2, no. 1 (April 1, 2015): 050–54. http://dx.doi.org/10.26699/jnk.v2i1.art.p050-054.
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Newborns in hospitals often have a variety of invasive procedures, so that the baby is experiencingpain. Baby’s sense of discomfort and fear which will result from the pain can be observed throughthe tears. While wrapping the newborn to fit in a blanket (swaddling) can soothe a fussy baby or cry. Thepurpose of this study was to identify the effect of swaddling on pain response in neonates after venousblood sampling procedures in hospitals Ngudi Waluyo Wlingi. This study was descriptive. Samplestaken by accidental sampling technique with a sample of 35 neonates. The results showed that swaddledneonates after venous blood sampling procedure was 80% (28 respondents) pulse between 120–160times per minute, 100% (35 respondents) respiration between 30–60 times per minute and 51.4% (18respondents) SaO2 is greater than 92%. Behavioral responses such as shrill and loud cry was 8.4% (24respondents), stretching in some facial muscles and facial muscles stretching along each was 4.2% (12respondents), a strong move is 5.95% (17 respondents ), and increased muscle tone face with flexion ofthe fingers and toes was 7.7% (22 respondents).Use of swaddling post venous blood sampling proceduresin neonates can be used as a way of making neonates feel comfortable and calm.
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McCarter, S., E. St. Louis, D. Sandness, K. Arndt, M. Erickson, G. Tabatabai, B. Boeve, and M. Silber. "Antidepressants increase REM sleep muscle tone in patients with and without REM sleep behavior disorder." Sleep Medicine 16 (December 2015): S3. http://dx.doi.org/10.1016/j.sleep.2015.02.005.
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Bennet-Clark, H. C. "Resonators in insect sound production: how insects produce loud pure-tone songs." Journal of Experimental Biology 202, no. 23 (December 1, 1999): 3347–57. http://dx.doi.org/10.1242/jeb.202.23.3347.
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In a resonant vibration, two reactive elements, such as a mass and a spring, interact: the resonant frequency depends on the magnitude of these two elements. The build-up and decay of the vibration depend on the way the resonator is driven and on the damping in the system. The evidence for the existence of resonators in insect sound production is assessed. The mechanics of different types of sound-producing system found in insects is described. Mechanical frequency-multiplier mechanisms, which convert the relatively slow contraction of muscles to the higher frequency of the sound, are commonly used to convert the comparatively slow muscle contraction rate to the higher frequency of the sound. The phasing and rate of mechanical excitation may also affect the frequency and duration of the sound that is produced. Although in many insects the song may appear to be produced by the excitation of a simple resonator, the song frequency may not be constant, suggesting that other factors, such as the mechanism of excitation, or variation of the effective mass or elasticity of the system during sound production, may be additional determinants of the song frequency. Loud, and hence efficient, transduction of the energy of a mechanical resonator into sound may involve a second stage of transduction which, by damping the resonator, may compromise tonal purity. Some insect singers resolve this problem by tuning both stages of transduction to the same frequency, thereby maintaining tonal purity.
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Sharmin, Shakila, Nazma Begum, and Soofia Khatoon. "Clinical Profile of Brain Tumour in Children." Journal of Shaheed Suhrawardy Medical College 8, no. 1 (March 7, 2017): 8–12. http://dx.doi.org/10.3329/jssmc.v8i1.31497.
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Background: This study was designed to evaluate the clinical profile and location of brain tumours in children so that brain tumour cases could be diagnosed and managed earlier.Materials and Methods: This cross sectional study was carried out from April 2011 to April 2012. A total 50 clinically suspected cases of brain tumour and supported by MRI were enrolled in this study.Results: Brain tumour of children was predominant in male where male to female ratio was almost 1.9:1. Supratentorial and Infratentorial brain tumour were found in 36% and 64% cases respectively in children. According to MRI findings in the supratentorial location, craniopharyngioma were commonest (50%) followed by cerebral astrocytoma (22.2%). In the infratentorial region, medulloblastoma was observed in (40.6%), followed by cerebellar astrocytoma (31.3%). Vertigo, weakness of limbs were found in 46.9% and 87.5% cases respectively in infratentorial group which were significantly (p<0.05) higher than supratentorial group. Growth failure and behavioral change were found in 16.7% and 22.2% cases respectively in supratentorial which were significantly (p<0.05) higher than infratentorial group. Papilloedema, reduced muscle power, increased muscle tone, exaggerated deep reflexes, clonus, gait disturbance and cerebellar signs were significantly (p<0.05) higher in infratentorial group.Conclusion: Craniopharyngioma and medulloblastoma were more common findings in MRI evaluation in the supratentorial and infratentorial location respectively. Growth failure and behavioral change were found higher in supratentorial than infratentorial group. Vertigo, weakness of limbs, papilloedema, reduced muscle power, increased muscle tone, exaggerated deep reflexes, clonus, gait disturbance and cerebellar signs were higher in infratentorial group.J Shaheed Suhrawardy Med Coll, June 2016, Vol.8(1); 8-12
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Kuznetsova, Larisa V., Nicole Tomasek, Gisli H. Sigurdsson, Andrej Banic, Dominique Erni, and Anthony M. Wheatley. "Dissociation between volume blood flow and laser-Doppler signal from rat muscle during changes in vascular tone." American Journal of Physiology-Heart and Circulatory Physiology 274, no. 4 (April 1, 1998): H1248—H1254. http://dx.doi.org/10.1152/ajpheart.1998.274.4.h1248.
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Although the laser-Doppler flowmetry (LDF) signal from skeletal muscle has been shown to provide a good measure of blood flow under some conditions, its behavior during administration of vasoactive substances has never been addressed. The aims of this study were to compare 1) changes in LDF signal with those in total muscle blood flow measured with radioactive microspheres after ganglionic blockade (chlorisondamine) and during administration of angiotensin II (ANG II), phenylephrine (PE), and isoproterenol (Iso) and 2) changes in vascular resistance estimated by the two techniques. The LDF signal from the biceps femoris muscle was investigated in anesthetized male Wistar rats. Ganglionic blockade led to a significant ( P < 0.05) fall in mean arterial pressure (MAP) [medians (lower, upper quartiles): 78 (72, 83) vs. 127 (114, 138) mmHg under basal conditions], muscle blood flow (MBF, microsphere technique; 61%), and the LDF signal (29%). Muscle vascular resistance (MVR = MAP/MBF) was increased (64%, P < 0.05), but vascular resistance estimated as MAP/LDF signal (MVRLDF) was unchanged. During ANG II and PE infusions, MAP rose ( P< 0.05) to 178 (155, 194) and 127 (124, 142) mmHg, respectively; MBF did not change compared with the preinfusion (postganglionic blockade) level and remained significantly ( P< 0.05) lower than baseline, whereas the LDF signal increased up to a level not different from baseline. MVR rose and was significantly ( P < 0.05) higher than baseline, whereas MVRLDF did not differ significantly from baseline. During Iso infusion, MAP fell [58 (56, 60) vs. 94 (92, 102) mmHg, P < 0.05], the LDF signal was reduced (49%, P < 0.05) despite a large increase in MBF (139%, P < 0.05), and MVR fell (74%, P < 0.05), whereas MVRLDF did not change vs. preinfusion level. Our results suggest that 1) changes in the LDF signal from muscle may not correlate with changes in total muscle blood flow measured by the microsphere technique during infusion of vasoactive substances and 2) the use of LDF data for estimation of MVR during changes in vascular tone in rat skeletal muscle is probably not appropriate.
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Davis, Michael J., and Michael A. Hill. "Signaling Mechanisms Underlying the Vascular Myogenic Response." Physiological Reviews 79, no. 2 (April 1, 1999): 387–423. http://dx.doi.org/10.1152/physrev.1999.79.2.387.
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The vascular myogenic response refers to the acute reaction of a blood vessel to a change in transmural pressure. This response is critically important for the development of resting vascular tone, upon which other control mechanisms exert vasodilator and vasoconstrictor influences. The purpose of this review is to summarize and synthesize information regarding the cellular mechanism(s) underlying the myogenic response in blood vessels, with particular emphasis on arterioles. When necessary, experiments performed on larger blood vessels, visceral smooth muscle, and even striated muscle are cited. Mechanical aspects of myogenic behavior are discussed first, followed by electromechanical coupling mechanisms. Next, mechanotransduction by membrane-bound enzymes and involvement of second messengers, including calcium, are discussed. After this, the roles of the extracellular matrix, integrins, and the smooth muscle cytoskeleton are reviewed, with emphasis on short-term signaling mechanisms. Finally, suggestions are offered for possible future studies.
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Wang, Hong-Zhan, Nancy Day, Mira Valcic, Ken Hsieh, Scott Serels, Peter R. Brink, and George J. Christ. "Intercellular communication in cultured human vascular smooth muscle cells." American Journal of Physiology-Cell Physiology 281, no. 1 (July 1, 2001): C75—C88. http://dx.doi.org/10.1152/ajpcell.2001.281.1.c75.
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Intercellular communication through gap junction channels plays a fundamental role in regulating vascular myocyte tone. We investigated gap junction channel expression and activity in myocytes from the physiologically distinct vasculature of the human internal mammary artery (IMA, conduit vessel) and saphenous vein (SV, capacitance vessel). Northern and Western blots documented the presence of connexin43 (Cx43) in frozen tissues and cultured cells from both vessels. Northern blots also confirmed the presence of Cx40 mRNA in cultured IMA and SV myocytes. Dual whole cell patch-clamp experiments revealed that macroscopic junctional conductance was voltage dependent and characteristic of that observed for Cx43. In the majority of records, in both vessels, single-channel activity was dominated by a main-state conductance of 120 pS, with subconducting events comprising less than 10% of the amplitude histograms. However, some records showed “atypical” unitary events that had a conductance similar to Cx40 (∼140–160 pS), but gating behavior like that of Cx43. As such, it is conceivable that the presence and coexpression of Cx40 and Cx43 in IMA and SV myocytes may result in heteromeric channel formation. Nonetheless, in terms of gating, Cx43-like behavior clearly dominates.
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Gokina, Natalia I., Kristen M. Park, Keara McElroy-Yaggy, and George Osol. "Effects of Rho kinase inhibition on cerebral artery myogenic tone and reactivity." Journal of Applied Physiology 98, no. 5 (May 2005): 1940–48. http://dx.doi.org/10.1152/japplphysiol.01104.2004.
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Several recent studies have implicated the RhoA-Rho kinase pathway in arterial myogenic behavior. The goal of this study was to determine the effects of Rho kinase inhibition (Y-27632) on cerebral artery calcium and diameter responses as a function of transmural pressure. Excised segments of rat posterior cerebral arteries (100–200 μm) were cannulated and pressurized in an arteriograph at 37°C. Increasing pressure from 10 to 60 mmHg triggered an elevation of cytosolic calcium concentration ([Ca2+]i) from 113 ± 9 to 199 ± 12 nM and development of myogenic tone. Further elevation of pressure to 120 mmHg induced only a minor additional increase in [Ca2+]i and constriction. Y-27632 (0.3–10 μM) inhibited myogenic tone in a concentration-dependent manner at 60 and 120 mmHg with comparable efficacy; conversely, sensitivity was decreased at 120 vs. 60 mmHg (50% inhibitory concentration: 2.5 ± 0.3 vs. 1.4 ± 0.1 μM; P < 0.05). Dilation was accompanied by further increases in [Ca2+]i and an enhancement of Ca2+ oscillatory activity. Y-27632 also effectively dilated the vessels permeabilized with α-toxin in a concentration-dependent manner. However, dilator effects of Y-27632 at low concentrations were larger at 60 vs. 100 mmHg. In summary, the results support a significant role for RhoA-Rho kinase pathway in cerebral artery mechanotransduction of pressure into sustained vasoconstriction (myogenic tone and reactivity) via mechanisms that augment smooth muscle calcium sensitivity. Potential downstream events may involve inhibition of myosin phosphatase and/or stimulation of actin polymerization, both of which are associated with increased smooth muscle force production.
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Cygan, Fanny, Delphine Oudiette, Laurène Leclair-Visonneau, Smaranda Leu-Semenescu, and Isabelle Arnulf. "Night-to-Night Variability of Muscle Tone, Movements, and Vocalizations in Patients with REM Sleep Behavior Disorder." Journal of Clinical Sleep Medicine 06, no. 06 (December 15, 2010): 551–55. http://dx.doi.org/10.5664/jcsm.27988.
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Abedi Khoozani, Parisa, and Gunnar Blohm. "Neck muscle spindle noise biases reaches in a multisensory integration task." Journal of Neurophysiology 120, no. 3 (September 1, 2018): 893–909. http://dx.doi.org/10.1152/jn.00643.2017.
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Reference frame transformations (RFTs) are crucial components of sensorimotor transformations in the brain. Stochasticity in RFTs has been suggested to add noise to the transformed signal due to variability in transformation parameter estimates (e.g., angle) as well as the stochastic nature of computations in spiking networks of neurons. Here, we varied the RFT angle together with the associated variability and evaluated the behavioral impact in a reaching task that required variability-dependent visual-proprioceptive multisensory integration. Crucially, reaches were performed with the head either straight or rolled 30° to either shoulder, and we also applied neck loads of 0 or 1.8 kg (left or right) in a 3 × 3 design, resulting in different combinations of estimated head roll angle magnitude and variance required in RFTs. A novel three-dimensional stochastic model of multisensory integration across reference frames was fitted to the data and captured our main behavioral findings: 1) neck load biased head angle estimation across all head roll orientations, resulting in systematic shifts in reach errors; 2) increased neck muscle tone led to increased reach variability due to signal-dependent noise; and 3) both head roll and neck load created larger angular errors in reaches to visual targets away from the body compared with reaches toward the body. These results show that noise in muscle spindles and stochasticity in general have a tangible effect on RFTs underlying reach planning. Since RFTs are omnipresent in the brain, our results could have implications for processes as diverse as motor control, decision making, posture/balance control, and perception. NEW & NOTEWORTHY We show that increasing neck muscle tone systematically biases reach movements. A novel three-dimensional multisensory integration across reference frames model captures the data well and provides evidence that the brain must have online knowledge of full-body geometry together with the associated variability to plan reach movements accurately.
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Amundsen-Huffmaster, Sommer L., Matthew N. Petrucci, Maria E. Linn-Evans, Jae Woo Chung, Michael J. Howell, Aleksandar Videnovic, Paul J. Tuite, Scott E. Cooper, and Colum D. MacKinnon. "REM Sleep Without Atonia and Gait Impairment in People with Mild-to-Moderate Parkinson’s Disease." Journal of Parkinson's Disease 11, no. 2 (April 13, 2021): 767–78. http://dx.doi.org/10.3233/jpd-202098.
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Background: Subtle gait deficits can be seen in people with idiopathic rapid eye movement (REM) sleep behavior disorder (RBD), a prodromal stage of Parkinson’s disease (PD) and related alpha-synucleinopathies. It is unknown if the presence and level of REM sleep without atonia (RSWA, the electromyographic hallmark of RBD) is related to the severity of gait disturbances in people with PD. Objective: We hypothesized that gait disturbances in people with mild-to-moderate PD would be greater in participants with RSWA compared to those without RSWA and matched controls, and that gait impairment would correlate with measures of RSWA. Methods: Spatiotemporal characteristics of gait were obtained from 41 people with PD and 21 age-matched controls. Overnight sleep studies were used to quantify muscle activity during REM sleep and group participants with PD into those with RSWA (PD-RSWA+, n = 22) and normal REM sleep muscle tone (PD-RSWA-, n = 19). Gait characteristics were compared between groups and correlated to RSWA. Results: The PD-RSWA+ group demonstrated significantly reduced gait speed and step lengths and increased stance and double support times compared to controls, and decreased speed and cadence and increased stride velocity variability compared to PD-RSWA- group. Larger RSWA scores were correlated with worse gait impairment in the PD group. Conclusion: The presence and level of muscle tone during REM sleep is associated with the severity of gait disturbances in PD. Pathophysiological processes contributing to disordered gait may occur earlier and/or progress more rapidly in people with PD and RBD.
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Elphick, M. R., and R. Melarange. "Neural control of muscle relaxation in echinoderms." Journal of Experimental Biology 204, no. 5 (March 1, 2001): 875–85. http://dx.doi.org/10.1242/jeb.204.5.875.
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Smooth muscle relaxation in vertebrates is regulated by a variety of neuronal signalling molecules, including neuropeptides and nitric oxide (NO). The physiology of muscle relaxation in echinoderms is of particular interest because these animals are evolutionarily more closely related to the vertebrates than to the majority of invertebrate phyla. However, whilst in vertebrates there is a clear structural and functional distinction between visceral smooth muscle and skeletal striated muscle, this does not apply to echinoderms, in which the majority of muscles, whether associated with the body wall skeleton and its appendages or with visceral organs, are made up of non-striated fibres. The mechanisms by which the nervous system controls muscle relaxation in echinoderms were, until recently, unknown. Using the cardiac stomach of the starfish Asterias rubens as a model, it has been established that the NO-cGMP signalling pathway mediates relaxation. NO also causes relaxation of sea urchin tube feet, and NO may therefore function as a ‘universal’ muscle relaxant in echinoderms. The first neuropeptides to be identified in echinoderms were two related peptides isolated from Asterias rubens known as SALMFamide-1 (S1) and SALMFamide-2 (S2). Both S1 and S2 cause relaxation of the starfish cardiac stomach, but with S2 being approximately ten times more potent than S1. SALMFamide neuropeptides have also been isolated from sea cucumbers, in which they cause relaxation of both gut and body wall muscle. Therefore, like NO, SALMFamides may also function as ‘universal’ muscle relaxants in echinoderms. The mechanisms by which SALMFamides cause relaxation of echinoderm muscle are not known, but several candidate signal transduction pathways are discussed here. The SALMFamides do not, however, appear to act by promoting release of NO, and muscle relaxation in echinoderms is therefore probably regulated by at least two neuronal signalling systems acting in parallel. Recently, other neuropeptides that influence muscle tone have been isolated from the sea cucumber Stichopus japonicus using body wall muscle as a bioassay, but at present SALMFamide peptides are the only ones that have been found to have a direct relaxing action on echinoderm muscle. One of the Stichopus japonicus peptides (holothurin 1), however, causes a reduction in the magnitude of electrically evoked muscle contraction in Stichopus japonicus and also causes ‘softening’ of the body wall dermis, a ‘mutable connective tissue’. It seems most likely that this effect of holothurin 1 on body wall dermis is mediated by constituent muscle cells, and the concept of ‘mutable connective tissue’ in echinoderms may therefore need to be re-evaluated to incorporate the involvement of muscle, as proposed recently for the spine ligament in sea urchins.
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Coulson, Rebecca J., Marilyn J. Cipolla, Lisa Vitullo, and Naomi C. Chesler. "Mechanical Properties of Rat Middle Cerebral Arteries With and Without Myogenic Tone." Journal of Biomechanical Engineering 126, no. 1 (February 1, 2004): 76–81. http://dx.doi.org/10.1115/1.1645525.
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The inner diameter and wall thickness of rat middle cerebral arteries (MCAs) were measured in vitro in both a pressure-induced, myogenically-active state and a drug-induced, passive state to quantify active and passive mechanical behavior. Elasticity parameters from the literature (stiffness derived from an exponential pressure-diameter relationship, β, and elasticity in response to an increment in pressure, Einc-p) and a novel elasticity parameter in response to smooth muscle cell (SMC) activation, Einc-a, were calculated. β for all passive MCAs was 9.11±1.07 but could not be calculated for active vessels. The incremental stiffness increased significantly with pressure in passive vessels; Einc-p 106 dynes/cm2 increased from 5.6±0.5 at 75 mmHg to 14.7±2.4 at 125 mmHg, (p<0.05). In active vessels, Einc-p 106 dynes/cm2 remained relatively constant (5.5±2.4 at 75 mmHg and 6.2±1.0 at 125 mmHg). Einc-a 106 dynes/cm2 increased significantly with pressure (from 15.1±2.3 at 75 mmHg to 49.4±12.6 at 125 mmHg, p<0.001), indicating a greater contribution of SMC activity to vessel wall stiffness at higher pressures.
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Nasiri, Jafar, Maryam Sedghi, and Mohammad Hossein Hemat. "Neurodevelopmental Outcome of Patients With Agenesis of Corpus Callosum." Caspian Journal of Neurological Sciences 7, no. 2 (April 1, 2021): 99–103. http://dx.doi.org/10.32598/cjns.7.25.2.
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Background: Agenesis of Corpus Callosum (ACC) is a type of brain dysgenesis with various clinical manifestations. Objectives: This study aimed to investigate the clinical and neurodevelopmental outcomes of patients with ACC. Materials & Methods: In this cross-sectional study, the clinical and neurodevelopmental conditions of 62 patients with complete ACC referred to subspecialty clinics of pediatric neurology, Isfahan University of Medical Sciences, Isfahan, Iran, were investigated. Quantitative data were shown as Mean±SD, and qualitative data as frequency or percentage. In addition, the f Chi-square test was used to compare some data in SPSS version 22. Results: In this study, 62 patients, including 29 boys and 33 girls with a Mean±SD age of 4.99±5.07 years, were included. Among the patients examined, 54.4% were born of consanguineous marriage, 82% had developmental delays, 80.4% had mental retardation, 89.1% had a speech delay, 23.7% had nutritional problems, 42.4% had facial dysmorphic features, and 27.6% had abnormalities of muscle tone. Among the associated problems stated by the patients, 15.5% of them had heart diseases, 22.4% visual disorders, 5.2% hearing deficit, 25.8% behavioral problems, 50% seizures, and 53.3% had abnormal electroencephalogram. Interestingly, 12.9% of the patients had normal or near-normal development. Conclusion: The prevalence of developmental delays, speech and language disorders, mental retardation, facial deformities, seizures, and abnormal muscle tone were common in the patients with ACC.
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Osol, George, Johan Fredrik Brekke, Keara McElroy-Yaggy, and Natalia I. Gokina. "Myogenic tone, reactivity, and forced dilatation: a three-phase model of in vitro arterial myogenic behavior." American Journal of Physiology-Heart and Circulatory Physiology 283, no. 6 (December 1, 2002): H2260—H2267. http://dx.doi.org/10.1152/ajpheart.00634.2002.
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Myogenic behavior, prevalent in resistance arteries and arterioles, involves arterial constriction in response to intravascular pressure. This process is often studied in vitro by using cannulated, pressurized arterial segments from different regional circulations. We propose a comprehensive model for myogenicity that consists of three interrelated but dissociable phases: 1) the initial development of myogenic tone (MT), 2) myogenic reactivity to subsequent changes in pressure (MR), and 3) forced dilatation at high transmural pressures (FD). The three phases span the physiological range of transmural pressures (e.g., MT, 40–60 mmHg; MR, 60–140 mmHg; FD, >140 mmHg in cerebral arteries) and are characterized by distinct changes in cytosolic calcium ([Ca2+]i), which do not parallel arterial diameter or wall tension, and therefore suggest the existence of additional regulatory mechanisms. Specifically, the development of MT is accompanied by a substantial (200%) elevation in [Ca2+]i and a reduction in lumen diameter and wall tension, whereas MR is associated with relatively small [Ca2+]i increments (<20% over the entire pressure range) despite considerable increases in wall tension and force production but little or no change in diameter. FD is characterized by a significant additional elevation in [Ca2+]i (>50%), complete loss of force production, and a rapid increase in wall tension. The utility of this model is that it provides a framework for comparing myogenic behavior of vessels of different size and anatomic origin and for investigating the underlying cellular mechanisms that govern vascular smooth muscle mechanotransduction and contribute to the regulation of peripheral resistance.
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Molen, Yara Fleury, Luciane Bizari Coin Carvalho, Lucila Bizari Fernandes do Prado, and Gilmar Fernandes do Prado. "Insomnia: psychological and neurobiological aspects and non-pharmacological treatments." Arquivos de Neuro-Psiquiatria 72, no. 1 (January 2014): 63–71. http://dx.doi.org/10.1590/0004-282x20130184.
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Insomnia involves difficulty in falling asleep, maintaining sleep or having refreshing sleep. This review gathers the existing informations seeking to explain insomnia, including those that focus on psychological aspects and those considered neurobiological. Insomnia has been defined in psychological (cognitive components, such as worries and rumination, and behavioral aspects, such as classic conditioning) and physiological terms (increased metabolic rate, with increased muscle tone, heart rate and temperature). From the neurobiological point of view, there are two perspectives: one which proposes that insomnia occurs in association with a failure to inhibit wakefulness and another that considers hyperarousal as having an important role in the physiology of sleep. The non-pharmacological interventions developed to face different aspects of insomnia are presented.
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Miyauchi, M., F. Ishibashi, M. Hondo, I. Shimizu, and M. Yanagisawa. "The effect of zonisamide on abnormal muscle tone during REM sleep in a mouse model of REM sleep behavior disorder." Sleep Medicine 40 (December 2017): e229. http://dx.doi.org/10.1016/j.sleep.2017.11.668.
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Devlin, C. L. "The pharmacology of gamma-aminobutyric acid and acetylcholine receptors at the echinoderm neuromuscular junction." Journal of Experimental Biology 204, no. 5 (March 1, 2001): 887–96. http://dx.doi.org/10.1242/jeb.204.5.887.
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This review describes the various subtypes of gamma-aminobutyric acid (GABA) receptors found at the echinoderm neuromuscular junction (NMJ), based on pharmacological and physiological studies. The review focuses mainly on holothurian GABA receptors at the NMJ located between the radial nerve and longitudinal muscle of the body wall (LMBW) and compares them to GABA receptors described at other echinoderm NMJs. Since a primary action of GABA on the holothurian LMBW is to modulate contractile responses to the excitatory neurotransmitter, acetylcholine (ACh), the pharmacology of echinoderm nicotinic ACh receptors (nAChRs) and muscarinic ACh receptors (mAChRs) is also addressed. GABA responses have been described in the asteroids, echinoids and holothuroids but not in the other echinoderm classes. Some actions of GABA on echinoderm muscle include regulation of basal tone and spontaneous rhythmic contractions and modulation of cholinergic responses. Both GABA A and B receptor subtypes are present at the echinoderm NMJ, a feature also common to the arthropods, molluscs and chordates. Echinoderm GABA A receptors may mediate the excitatory responses to GABA. The GABA A receptor antagonist bicuculline has a paradoxical effect on contractility, stimulating large protracted contractions of the LMBW. The GABA A agonist muscimol potentiates cholinergic contractions of the holothurian LMBW. Another population of GABA receptors is inhibitory and is sensitive to the GABA B agonist baclofen and GABA B antagonists phaclofen and 2-OH-saclofen. The pre- and/or postsynaptic location of the GABA A and B receptors is not currently known. The folded GABA analogue 4-cis-aminocrotonic acid has no effect on the contractility of the holothurian LMBW so GABA C receptors are probably lacking in this preparation. Pharmacological studies have shown that distinct nAChRs and mAChRs are colocalized in numerous echinoderm muscle preparations. Most recently, nAChR agonists were used to characterize pharmacologically receptors at the holothurian LMBW that bind ACh. Nicotinic AChRs with unique pharmacological profiles are localized both pre- and postsynaptically at this NMJ, where their physiological action is to enhance muscle tone. Muscarinic agonists also have excitatory actions on the LMBW but their action is to stimulate phasic, rhythmic contractions of the muscle. The location of mAChRs at the echinoderm NMJ, however, is unknown.Since most of the studies described in the present review have used whole-mount preparations consisting largely of a combination of muscle fibers, neurons and connective tissue, it is extremely difficult to determine pharmacologically the exact location of the various receptor subtypes. Additional electrophysiological studies on isolated neurons and muscle fibers are therefore required to clearly define extra-, pre- and/or postsynaptic sites for the receptor subtypes at the echinoderm NMJ.
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Tawhai, Merryn H., and Jason H. T. Bates. "Multi-scale lung modeling." Journal of Applied Physiology 110, no. 5 (May 2011): 1466–72. http://dx.doi.org/10.1152/japplphysiol.01289.2010.
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Multi-scale modeling of biological systems has recently become fashionable due to the growing power of digital computers as well as to the growing realization that integrative systems behavior is as important to life as is the genome. While it is true that the behavior of a living organism must ultimately be traceable to all its components and their myriad interactions, attempting to codify this in its entirety in a model misses the insights gained from understanding how collections of system components at one level of scale conspire to produce qualitatively different behavior at higher levels. The essence of multi-scale modeling thus lies not in the inclusion of every conceivable biological detail, but rather in the judicious selection of emergent phenomena appropriate to the level of scale being modeled. These principles are exemplified in recent computational models of the lung. Airways responsiveness, for example, is an organ-level manifestation of events that begin at the molecular level within airway smooth muscle cells, yet it is not necessary to invoke all these molecular events to accurately describe the contraction dynamics of a cell, nor is it necessary to invoke all phenomena observable at the level of the cell to account for the changes in overall lung function that occur following methacholine challenge. Similarly, the regulation of pulmonary vascular tone has complex origins within the individual smooth muscle cells that line the blood vessels but, again, many of the fine details of cell behavior average out at the level of the organ to produce an effect on pulmonary vascular pressure that can be described in much simpler terms. The art of multi-scale lung modeling thus reduces not to being limitlessly inclusive, but rather to knowing what biological details to leave out.
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Littleton-Kearney, Marguerite, and Patricia D. Hurn. "Testosterone as a Modulator of Vascular Behavior." Biological Research For Nursing 5, no. 4 (April 2004): 276–85. http://dx.doi.org/10.1177/1099800403262927.
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Male sex is an acknowledged risk factor for many forms of cardiovascular disease, and vascular disease prevalence patterns appear to be different in men versus women. The vascular properties of the principal mammalian androgen, testosterone, are complex and linked to dose, duration of exposure, presence of underlying vascular disease, and, possibly, biological sex. Data from isolated vessels and animal models suggest that pharmacological doses of testosterone, or its potent intracellular metabolite dihydrotestosterone, produce vasodilation. Testosterone’s major effect on vascular beds at physiologic concentrations remains unclear, with documentation of both vasodilatory and vasoconstrictive actions. Results of various studies suggest that testosterone can alter vascular tone through both endothelium-dependent and endothelium-independent mechanisms in a variety of vascular beds and vessel types. Testosterone’s endothelium-dependent effects are likely mediated at least in part through nitric oxide (NO) elaboration, whereas mechanisms of endothelium-independent effects involve 1 or more types of smooth muscle ion conductance channels. Data from clinical studies indicate that, in men, androgen replacement may provide beneficial effects when coronary artery disease is present. Conversely, in women, testosterone may augment existing hypertension, increase risk for cardio-vascular events, or promote atherogenesis. However, it should be emphasized that most of these observations are anecdotal or come from small-scale clinical studies, and limited information is available in women. New research is required to understand the potential efficacy of androgen therapy, or lack thereof. This review focuses on current understanding of testosterone’s physiological effects on vascular behavior and of testosterone’s putative role in vascular health and disease.
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Sirirassamee, Tawima, Sasiwan Phoolsawat, and Supakorn Limkhunthammo. "Relationship between body weight perception and weight-related behaviours." Journal of International Medical Research 46, no. 9 (June 13, 2018): 3796–808. http://dx.doi.org/10.1177/0300060518780138.
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Objectives This study aimed to examine the prevalence of weight misperception and to explore the association of weight perception with physical activity and dietary intake. Methods A population-based, nationally representative cross-sectional survey was conducted of 920 Thai adolescents aged 13 to 24 years. Respondents were selected using stratified multistage sampling. Respondents who agreed to participate were asked to complete the Youth Risk Behavior Questionnaire. Results Females were more likely than males to misperceive themselves as overweight (21.8% vs. 11.7%), whereas males were more likely than females to misperceive themselves as underweight (12.3% vs. 3.4%). Males were more likely than females to report a high intake of vegetables (45.7% vs. 38.0%), milk (39.1% vs. 38.0%), 100% fruit juice (20.9% vs. 17.7%) and soda or pop (38.5% vs. 20.6%). Males were also more likely than females to report vigorous physical activity of more than 60 minutes per day (38.1% vs. 21.3%) and vigorous exercise to strengthen or tone muscles (37.3% vs. 13.2%). Conclusions Gender differences in dietary intake and physical activity were identified. However, there were no significant differences in dietary intake and physical activity between adolescents who correctly perceived themselves as overweight and those who misperceived themselves as overweight.
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Mayston, Margaret J. "People With Cerebral Palsy: Effects of and Perspectives for Therapy." Neural Plasticity 8, no. 1-2 (2001): 51–69. http://dx.doi.org/10.1155/np.2001.51.
Full textAbstract:
The movement disorder of cerebral palsy (CP) is expressed in a variety of ways and to varying degrees in each individual. The condition has become more complex over the last 20 years with the increasing survival of children born at less than 28 to 30 weeks gestationai age. Impairments present in children with CP as a direct result of the brain injury or occurring indirectly to compensate for underlying problems include abnormal muscle tone; weakness and lack of fitness; limited variety of muscle synergies; contracture and altered biomechanics, the net result being limited functional ability. Other contributors to the motor disorder include sensory, cognitive and perceptual impairments. In recent years understanding of the motor problem has increased, but less is known about effects of therapy. Evidence suggests that therapy can improve functional possibilities for children with cerebral palsy but is inconclusive as to which approach might be most beneficial. The therapist requires an understanding of the interaction of all systems, cognitive/perceptual, motor, musculoskeletal, sensory and behavioral, in the context of the development and plasticity of the CNS. It is necessary to understand the limitations of the damaged immature nervous system, but important to optimize the child's functional possibilities.