Serum levels of soluble Fas in patients with Graves' ophthalmopathy.
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AIM: To assess levels of soluble Fas (sFas) in the sera of patients with Graves' ophthalmopathy. METHODS: The subjects in this study were 43 patients with Graves' ophthalmopathy and 11 normal subjects. Serum levels of sFas were determined by sandwich enzyme linked immunosorbent assay. In addition, serum levels of thyroid stimulating antibody (TSAB) were also measured in all the patients. RESULTS: The mean serum level of sFas was 1.35 (SD 2.03) ng/ml in patients with Graves' ophthalmopathy, and 0.93 (0.32) ng/ml in normal subjects. Serum levels of sFas in the subgroup of 24 patients with diplopia (1.98 (2.56) ng/ml) were significantly higher than those in the subgroup of 19 patients without diplopia (0.56 (0.24) ng/ml) and normal subjects (p <0.001). Serum levels of sFas in the subgroup of 27 patients with extraocular muscle hypertrophy (1.81 (2. 46) ng/ml) were significantly higher than those in the subgroup of 16 patients without extraocular muscle hypertrophy (0.58 (0.26) ng/ml) among the patients with Graves' ophthalmopathy and normal subjects (p <0.001). Serum levels of sFas were not significantly different between the subgroup of 24 patients with proptosis (1.15 (0.98) ng/ml) and the subgroup of 19 patients without proptosis (1. 61 (2.88)). In contrast, the serum levels of TSAB in the subgroup of patients with proptosis (723% (1161%)) were significantly higher than those in the subgroup of patients without proptosis (194% (122%)) (p <0.05). CONCLUSIONS: Elevated sFas levels were associated with extraocular muscle disorders but not with proptosis. On the other hand, elevated TSAB levels were associated with proptosis but not with extraocular muscle disorders, suggesting different immunological mechanisms for the extraocular muscle disorders and proptosis in Graves' ophthalmopathy. Determination of the serum levels of sFas and TSAB could provide useful markers for evaluation of the immunological processes involved in the development of Graves' ophthalmopathy. (+info)
Craniofacial pain and motor function: pathogenesis, clinical correlates, and implications.
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Many structural, behavioral, and pharmacological interventions imply that favorable treatment effects in musculoskeletal pain states are mediated through the correction of muscle function. The common theme of these interventions is captured in the popular idea that structural or psychological factors cause muscle hyperactivity, muscle overwork, muscle fatigue, and ultimately pain. Although symptoms and signs of motor dysfunction can sometimes be explained by changes in structure, there is strong evidence that they can also be caused by pain. This new understanding has resulted in a better appreciation of the pathogenesis of symptoms and signs of the musculoskeletal pain conditions, including the sequence of events that leads to the development of motor dysfunction. With the improved understanding of the relationship between pain and motor function, including the inappropriateness of many clinical assumptions, a new literature emerges that opens the door to exciting therapeutic opportunities. Novel treatments are expected to have a profound impact on the care of musculoskeletal pain and its effect on motor function in the not-too-distant future. (+info)
Conditioned eyeblink response consists of two distinct components.
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The aim of these experiments was to obtain a detailed knowledge of how the orbicularis oculi muscle is activated during the execution of a conditioned eyeblink response (CR). This is the first critical step to understand the underlying neural mechanisms involved in the control of the CR. Decerebrate ferrets were trained in a classical conditioning paradigm. The conditioned stimulus (CS) was a train of electrical stimuli (15 pulses, 50 Hz, 1 mA) applied to the forelimb, and the unconditioned stimulus (US) was a train of electrical stimuli (3 pulses, 50 Hz, 3-4 mA) to the periorbital region. The CRs were studied by recording electromyograms (EMGs) from the orbicularis oculi muscle. The eyeblink CR in all animals showed a similar topography with at least two different components, CR1 and CR2, which were expressed at different rates. CR1 appeared first during acquisition, had a shorter onset latency, and was more phasic and more resistant to extinction than CR2. A marked pause in the muscle activity separated the two components. To control that the two-component CR were not species, paradigm or preparation specific, awake rabbits were trained with a tone CS (300 ms, 4 kHz, 64 dB) and a train of periorbital stimuli as US (3 pulses, 50 Hz, 3 mA). CR1 and CR2 were present in the rabbit eyeblink CR. The cerebellum is implicated in the control of CRs and to study whether separate neural pathways were responsible for CR1 and CR2, direct brachium pontis stimulation was used to replace the forelimb CS. CR1 and CR2 were present in the CR elicited by the brachium pontis CS. The presence of CR1 and CR2 after a unilateral lesion of the brachium conjunctivum shows that output from the contralateral cerebellar hemisphere was not the cause for any of the components. Other mechanisms that might be involved in the separation of the CR into two components are discussed. The results show that the eyeblink CR consists of at least two components, CR1 and CR2, which most likely originate either as a direct central command from the cerebellum or in the output pathway before the facial nucleus. (+info)
Kinetic and frequency-domain properties of reflex and conditioned eyelid responses in the rabbit.
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Eyelid position and the electromyographic activity of the orbicularis oculi muscle were recorded unilaterally in rabbits during reflex and conditioned blinks. Air-puff-evoked blinks consisted of a fast downward phase followed sometimes by successive downward sags. The reopening phase had a much longer duration and slower peak velocity. Onset latency, maximum amplitude, peak velocity, and rise time of reflex blinks depended on the intensity and duration of the air puff-evoking stimulus. A flashlight focused on the eye also evoked reflex blinks, but not flashes of light, or tones. Both delayed and trace classical conditioning paradigms were used. For delayed conditioning, animals were presented with a 350-ms, 90-dB, 600-Hz tone, as conditioned stimulus (CS). For trace conditioning, animals were presented with a 10-ms, 1-k/cm(2) air puff, as CS. The unconditioned stimulus (US) consisted of a 100-ms, 3-k/cm(2) air puff. The stimulus interval between CS and US onsets was 250 ms. Conditioned responses (CRs) to tones were composed of downward sags that increased in number through the successive conditioning sessions. The onset latency of the CR decreased across conditioning at the same time as its maximum amplitude and its peak velocity increased, but the time-to-peak of the CR remained unaltered. The topography of CRs evoked by short, weak air puffs as the CS showed three different components: the alpha response to the CS, the CR, and the reflex response to the US. Through conditioning, CRs showed a decrease in onset latency, and an increase in maximum amplitude and peak velocity. The time-to-peak of the CR remained unchanged. A power spectrum analysis of reflex and conditioned blink acceleration profiles showed a significant approximately 8-Hz oscillation within a broadband of frequencies between 4 and 15 Hz. Nose and mandible movements presented power spectrum profiles different from those characterizing reflex and conditioned blinks. It is concluded that eyelid reflex responses in the rabbit present significant differences from CRs in their profiles and metric properties, suggesting different neural origins, but that a common approximately 8-Hz neural oscillator underlies lid motor performance. According to available data, the frequency of this putative oscillator seems to be related to the species size. (+info)
Reduced genioglossal activity with upper airway anesthesia in awake patients with OSA.
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We examined whether topical upper airway anesthesia leads to a reduction in genioglossal (GG) electromyogram (EMG) in patients with obstructive sleep apnea (OSA). Airway mechanics were also evaluated. In 13 patients with OSA, we monitored GG EMG during tidal breathing and during the application of pulses of negative airway pressure (-10 to -12 cmH(2)O). Airflow resistance and airway collapsibility were determined. All measurements were performed with and without topical anesthesia (lidocaine). Anesthesia led to a significant fall in the peak GG EMG response to negative pressure from 36.1 +/- 4.7 to 24.8 +/- 5.3% (SE) of maximum (P < 0.01). This was associated with a fall in phasic and tonic EMG during tidal breathing (phasic from 24.4 +/- 4.1 to 16.4 +/- 3.4% of maximum and tonic from 10.9 +/- 1.6 to 8.0 +/- 1.3% of maximum, P < 0.01). A significant rise in pharyngeal airflow resistance was also observed. Our results demonstrate that topical receptor mechanisms in the nasopharynx importantly influence dilator muscle activity and are likely important in driving the augmented dilator muscle activity seen in the apnea patient. (+info)
Role of reinsertion of the lower eyelid retractor on involutional entropion.
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AIMS: To verify and evaluate the effect of reinsertion of the lower eyelid retractor aponeurosis to correct involutional entropion. METHODS: The involutional entropion is one affection that occurs mainly in the lower eyelid of patients over 60 years old. The surgical techniques proposed to correct this condition are based on correction of horizontal laxity-the preseptal orbicularis muscle overrides the pretarsal muscle, and the reinsertion of the lower eyelid retractor aponeurosis. 30 patients clinically diagnosed with involutional entropion and randomly selected underwent reinsertion of the lower eyelid retractor aponeurosis to the tarsal plate, without horizontal shortening or resection of the skin or orbicularis muscle. RESULTS: Good anatomical and functional correction was achieved in 96.6% of the patients and no recurrence was observed on 29 month follow up examination. The surgical result was very satisfactory. CONCLUSIONS: It was concluded that this procedure is effective and has low recurrence rate, showing the important role of the reinsertion of the lower eyelid retractor aponeurosis in this surgical correction. (+info)
Signs of temporomandibular disorders in girls receiving orthodontic treatment. A prospective and longitudinal comparison with untreated Class II malocclusions and normal occlusion subjects.
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The aim of this investigation was to prospectively and longitudinally study signs of temporomandibular disorders (TMD) and occlusal changes in girls with Class II malocclusion receiving orthodontic treatment and to compare them with subjects with untreated Class II malocclusions and with normal occlusion subjects. Three groups of age-matched adolescent girls were examined for clinical signs of TMD and re-examined 2 years later. Sixty-five Class II subjects received orthodontic fixed straight-wire appliance treatment (Orthodontic group), 58 subjects were orthodontically untreated (Class II group), and 60 subjects had a normal occlusion (Normal group). In the Orthodontic group, the prevalence of muscular signs of TMD was significantly less common post-treatment. The Class II and the Normal groups showed minor changes during the 2-year period. Temporomandibular joint clicking increased in all three groups over the 2 years, but was less common in the Normal group. The Normal group also had a lower overall prevalence of signs of TMD than the Orthodontic and the Class II groups at both registrations. Functional occlusal interferences decreased in the Orthodontic group, but remained the same in the other groups over the 2 years. In conclusion, orthodontic treatment did not increase the risk for or worsen pretreatment signs of TMD. On the contrary, subjects with Class II malocclusions and signs of TMD of muscular origin seemed to benefit functionally from orthodontic treatment in a 2-year perspective. The Normal group had a lower prevalence of signs of TMD than the Orthodontic and the untreated Class II groups. (+info)
Facial visceral motor neurons display specific rhombomere origin and axon pathfinding behavior in the chick.
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In the chick embryo, facial motor neurons comprise branchiomotor and visceral motor subpopulations, which innervate branchial muscles and parasympathetic ganglia, respectively. Although facial motor neurons are known to develop within hindbrain rhombomere 4 (r4) and r5, the precise origins of branchiomotor and visceral motor neuron subpopulations are unclear. We investigated the organization and axon pathfinding of these motor neurons using axonal tracing and rhombomere transplantation in quail-chick chimeras. Our results show that a large majority of branchiomotor neurons originate in r4 but that a cohort of these neurons undergoes a caudal migration from r4 into r5. By contrast, visceral motor neurons develop exclusively in r5. We found that a striking property of facial visceral motor neurons is the ability of their axons to navigate back to appropriate ganglionic targets in the periphery after heterotopic transplantation. These results complement previous studies in which heterotopic facial branchiomotor neurons sent axons to their correct, branchial arch, target. By contrast, when trigeminal branchiomotor neurons were transplanted heterotopically, we found that they were unable to pathfind correctly, and instead projected to an inappropriate target region. Thus, facial and trigeminal motor neuron populations have different axon pathfinding characteristics. (+info)