[Indications for eye muscle operations in adult patients].
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Adult↗
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Results for “EYES, MUSCLES”
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Effects of eye muscle proprioceptive activation: morphological particularities of human extraocular muscle spindles.
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Aging↗
[Changes in saccades in endocrine orbitopathy. Clarification of the contribution by H. D. Schworm et al. "Functional eye muscle changes in endocrine orbitopathy"].
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Graves Disease↗
Cobblestone lissencephaly with normal eyes and muscle.
Cobblestone lissencephaly is the characteristic brain malformation observed in Fukuyama congenital muscular dystrophy (FCMD), muscle-eye-brain disease (MEB), and Walker-Warburg syndrome (WWS). The diagnostic criteria for all three require the presence of congenital muscular dystrophy, and criteria for MEB and WWS require retinal abnormalities. We report three patients from two consanguineous families of Middle Eastern origin with cobblestone lissencephaly but no abnormalities of the eyes or muscle. Based on the current diagnostic criteria for the cobblestone lissencephaly syndromes, this disorder must be classified separately from the others, but it may well be allelic to MEB and WWS. Linkage studies have excluded the gene for this disorder from the region of the FCMD gene on chromosome 9q31-32.
Adolescent↗
Microscopic study of muscle spindles in recti muscles of human fetal eye.
Muscle spindles of recti muscles of the eyebulb appear in the 11th week of intrauterine life. At first, the spindle manifests the stage of myotube with 2-3 intrafusal fibers and is surrounded by the monolayer of internal capsule. In the course of subsequent development, the number of intrafusal fibers increases. Internal capsule begins to demonstrate two layers (14th week) and, then, external capsule develops (17th week). In the 20th week, mature spindles have been observed with a multilayered external capsule.
Embryonic and Fetal Development↗
[Magnetic resonance tomographic differentiation of ocular muscle changes in endocrine orbitopathy].
In 50 patients with Graves' Ophthalmopathy and 9 controls both orbits were examined by MR Imaging at 0.5 Tesla using a surface coil. T1-weighted spin-echo images were obtained in transverse and coronal orientation; additionally, a T2-image was calculated from a multi-echo sequence (8 echoes). Signal intensity of eye muscles on both T1-weighted and T2-weighted MR images was evaluated qualitatively. T2-times were then calculated for all inferior rectus muscles. Eye muscle enlargement was found in 28 out of 50 patients. T2-times of inferior rectus muscles in stage III and IV patients were evaluated significantly (p less than 0.05). Areas of high signal intensity were accordingly found in enlarged eye muscles in 19 out of 50 patients; they were interpreted as edematous tissue changes. Areas of low signal intensity were found in enlarged eye muscles of 5 out of 50 patients; these eye muscles were considered fibrotic. Differentiation of eye muscle changes by MR imaging might help to decide between antiinflammatory medication and surgical therapy in patients with Graves' Ophthalmopathy.
Adolescent↗
Zinc distribution in various tissues, (brain, eye, skin, muscle and blood) of rat during hindlimb suspension.
Postural changes in 1-G environment induce well documented haemodynamic changes. On going from Earth's 1-G environment to the microgravity of space a marked cephalic blood volume shift occurs in humans with a subsequent loss of 2-3 L of fluid determined by diuresis and decreased fluid intake. Moreover, a number of transient changes in serum concentrations of sodium, potassium and calium have been observed in astronauts during spaceflight. It is conceivable that changes in the fluid status, and reduced muscle activities, which are changed by the microgravity environment, would also result in redistribution of some trace elements, such as zinc, copper and manganese. In particular, zinc metabolism, directly involved in many physiological processes, can be altered by a wide variety of factors including stress, rest, exercise, hormones and diet. Some of the microgravity-induced responses in space can be simulated in humans by using the posture of head-down tilt, and in rat by using the posture of hindlimb suspension. The aim of the present study was to investigate the effects of hindlimb suspension for 3-14 days on sodium, potassium and zinc content in various rat tissues including blood, muscle, brain, eye and nose's skin.
Animals↗
[Pseudoparalytic myasthenia gravis. Diagnostic and therapeutic aspects in 60 separate cases].
Based on 60 of our own cases and on the medical literature the authors discuss the diagnostic, pathophysiological and therapeutic aspects of myasthenia gravis. Myasthenia is suspected in cases of motor weakness of changing intensity, diminishing by rest. The weak muscles are innervated by different peripheral nerves. At the beginning a weakness of upperlid-muscles, external eye muscles and bulbar muscles is particularly frequent. There is no sensory loss or other neurological symptoms. A transitory disappearance of motor weakness after an intravenous dose of Edrophonium (Tensilon) is a typical diagnostic sign. The effect is less evident with eye-muscle weakness. A typical appearance of potentials after repetitive stimulation of peripheral nerves as well as other characteristics in electrophysiological testing of muscles are of high diagnostic value. This allows differentiation from other types of muscle weakness. In the pathogenesis of myasthenia an autoimmune process related to a persistent thymus gland plays an important part. This leads to an ultrastructural change in the postsynaptic membrane of the muscle fibre. The postsynaptic membrane no longer reacts in a normal way to acetylcholine as a transmitter substance at the level of the motor endplate. Therefore the first step in the treatment of myasthenia consists of cholinesterase-inhibitors, specially Neostigmin (Prostigmin) and Pyridostigmin (Mestinon). Thymectomy is advised in all cases of myasthenia with the exception of the pure ocular form and of myasthenia in patients older than 60 years. The thymus gland is practically always persistent or hypertrophic in myasthenia. The suprasternal access is recommended. A thymoma should always be operated upon because of the danger of malignancy. In cases where thymectomy is not performed or not successful and if cholinesterase-inhibitors are not sufficiently efficient, treatment with corticosteroids or ACTH is recommended.
Adolescent↗
Sensory control of extraocular muscles.
The role of sensory receptors in eye muscles is not well understood, but there is physiological and clinical evidence for the presence of proprioceptive signals in many areas of the central nervous system. It is unclear which structures generate these sensory signals, and which central neural pathways are involved. Three different types of receptors are associated with eye muscles: (1) muscle spindles, (2) palisade endings, and (3) Golgi tendon organs, but their occurrence varies wildly between species. A review of their organization shows that each receptor is mainly confined to a morphologically separate layer of the eye muscle. The palisade endings - which are unique to eye muscles, are associated with the global layer; and they have been found in all mammals studied so far. Their function is unknown. The muscle spindles, if they are present in a species, lie in the orbital layer, or at its junction to the global layer. Golgi tendon organs appear to be unique to artiodactyls (i.e., sheep and goats, etc.); they lie in an outer distal marginal layer of the eye muscle, called the "peripheral patch layer" in sheep. The specific association between palisade endings and the multiply innervated type of muscle fibers of the global layer has led to the hypothesis that together they may act as a sensory receptor, and provide a source of central proprioceptive signals. But other interpretations of the morphological evidence do not support this role.
Afferent Pathways↗
Morphometric features of recti muscles of the eye and their muscle spindles in human fetuses.
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Embryonic and Fetal Development↗
Mechanism and possible behavioural relevance of retinal movements in the ctenid spider Cupiennius salei
Like most spiders, the nocturnal hunting spider Cupiennius salei is able to move the retinae of its antero-median (AM) eyes. In the present study, the morphological and physiological properties of the eye muscles and the mechanism and behavioural relevance of retinal movements are investigated. The retinal movements are brought about by two forces: (i) contractions of the dorsal and ventral eye muscles, and (ii) the passive elastic restoring force of the eye tube and eye muscles (the presumed counteracting force). The dorsal eye muscle consists of 15­18 striated fibres and is 600 µm long. The ventral eye muscle is longer (650 µm) and consists of 20­22 striated fibres. The direction of the gaze of the retinae brought about by the eye muscles (active retinal movements) depends on the contraction states of the two eye muscles. The medially directed action of both eye muscles does not allow active movements of the eye tube in any lateral direction. Thus, the direction of gaze cannot actively be shifted medially. After active displacement of the retina, the elasticity of the eye tube and eye muscles passively moves the eye tube back to its resting position. There are two types of retinal movements. (i) Spontaneous microsaccades (duration 80 ms; excursion 3 °) are caused by the spontaneous contraction of only the dorsal eye muscle. They are ideally suited for preventing the adaptation of the sensory cells since their mean excursion (3 °) perfectly fits the inter-receptor angle (2.9 °) in the AM eye of Cupiennius salei. (ii) Induced movements (duration 100­500 ms; excursions 4­15 °) are caused by the contraction of both eye muscles and occur only after mechanical stimulation. Induced movements were elicited by stimulating the mechanosensory organs (trichobothria and slit sense organs) of the spider's legs. A stimulus on one side of the spider induces movements of the ipsilateral retina only. We therefore suggest that induced retinal movements are saccades shifting the gaze of the spider laterally towards the site of mechanical stimulation. According to behavioural experiments, the ability of a spider to locate an immobile target is highly impaired after blinding its AM eyes. We suggest that the motility of the AM eyes is required to locate stationary objects.
Journal Article↗
[Muscle antigens recognized with autoantibodies in patients with Graves' ophthalmopathy].
The aim of this work was to characterise the eye muscle antigens reacting with autoantibodies from Graves ophthalmopathy patients to elucidate the function of these antibodies. As estimated by ELISA test antibodies of IgG class reacting with porcine microsomal membranes are present in about 25% of patients while of IgM class in about 15% of patients with Graves ophthalmopathy. Their presence do not correlate with ophthalmopathy index, neither they have relation to treatment. Anti eye muscle antibodies were present at some stages of the disease in three patients who develop ophthalmopathy, from the group of 26 patients treated during one year for hyperthyroidism. However, sporadically these antibodies were found also in about 20% of patients with Hashimoto disease, Lupus erythematosus or Scleroderma. Some of them cross react with antigens of skeletal muscle and liver. Eye muscle antigens reacting with patients antibodies are localised in plasma membranes and in membranes of smooth reticulum. Affinity purification of solubilised porcine eye muscle membrane proteins on a column with immunoglobulins from pooled serum of patients resulted in 23 fold purification of the antigen. The sensitivity of ELISA was not significantly increased by the use of affinity purified antigen, however some of previously negative ophthalmopathy sera gave positive reaction. Porcine eye muscle membrane proteins were separated by SDS PAGE and transferred to nitrocellulose. The reactions of electroblotted proteins with sera from patients with Graves ophthalmopathy and also sera from healthy controls shown very complex pattern. There was not a single antigen or antigens reacting only with antibodies present in sera of ophthalmopathy patients and not in controls. Patients sera reacted more often than control sera with an antigen of about 40 kDa. The reaction of sera from some patients with proteins about 100, 70 and 65 kDa were stronger than between these proteins and control sera. No changes in the pattern of reaction between antibodies and eye muscle antigens were noticed in serum of the same Graves' patient with or without ophthalmopathy during one year follow up and treatment, regardless of clinical course of the disease. When human eye muscle membrane fractions from tissue obtained during strabismus repair or at autopsy was used for immunoblotting, smaller number of proteins reacted with autoantibodies. Again there was no single antigen or antigens reacting with antibodies from sera of all Graves ophthalmopathy patients. Sera of some patients reacted with antigens about 50 kDa, not recognized by controls. The results of present study show, that the anti eye muscle antibodies are present in some of Graves ophthalmopathy patients.(ABSTRACT TRUNCATED AT 400 WORDS)
Antigens↗
The pigeon optokinetic system: visual input in extraocular muscle coordinates.
The generation of compensatory eye movements in response to rotational head movements involves the transformation of visual-optokinetic and vestibular signals into commands controlling the appropriate eye muscles. Previously, it has been shown that the three systems (optokinetic, vestibular, and eye muscle) share a similar three-dimensional reference frame. In this report, we suggest that a peculiarity in the structure of the horizontal recti in pigeons demonstrates that the optokinetic system is organized with respect to the eye muscles rather than the vestibular canals. Measurements of the orientation of the plane for each of the lateral and medial recti were obtained. These were compared with the direction preferences of optokinetic neurons responsive to horizontal motion, namely "back" units in the nucleus of the basal optic root (nBOR), "forward" units in the pretectal nucleus lentiformis mesencephali (LM), and "vertical axis" (VA) Purkinje cells in the flocculus. The average direction preference of LM neurons excited in response to forward (temporal to nasal) visual motion, and VA Purkinje cells in response to optokinetic motion in the ipsilateral visual field was approximately parallel to the visual horizontal. This corresponded to the orientation of the medial rectus, which was also approximately parallel to the visual horizontal. The average direction preference of nBOR neurons excited in response to backward (nasal to temporal) visual motion, and VA Purkinje cells in response to optokinetic motion in the contralateral visual field was approximately 20-30 deg down from the visual horizontal. The orientation of the lateral rectus was also approximately 20-30 deg down from the visual horizontal. These data suggest that the incoming optokinetic signals are organized with respect to the outgoing extraocular muscle commands.
Animals↗
Use of monoclonal antibodies to investigate a possible role of thyroglobulin in the pathogenesis of Graves' ophthalmopathy.
One possible mechanism for Graves' ophthalmopathy is that the progressive orbital inflammation is initiated by formation of thyroglobulin (Tg)-anti-Tg immune complexes at sites of Tg binding to extraocular muscle membranes. In this study monoclonal antibodies (MCAB) against human Tg were used as probes (1) to identify Tg in eye muscle membranes prepared from normal subjects and (2) to measure binding of human Tg and Tg-anti-Tg immune complexes to eye muscle membranes. Reactivity of anti-Tg MCAB with Tg, thyroid, and eye muscle membranes was determined by binding of [125I]anti-Tg monoclonal antibody, an enzyme-linked immunosorbent assay (ELISA), and the indirect immunofluorescence technique. Seven membrane fractions, prepared by differential sucrose gradient centrifugation, were used. Whereas [125I]anti-Tg MCAB bound to all thyroid membrane fractions tested, no [125I]anti-Tg bound to eye muscle membranes. Similarly, reactivity of anti-Tg MCAB with eye muscle membranes was not demonstrated in ELISA or immunofluorescence tests. Although Tg-anti-Tg immune complexes bound to thyroid membranes, such complexes did not bind to eye muscle membranes. Significant binding of [125I]human Tg to eye muscle or thyroid membranes was not demonstrated for any membrane preparation. On the other hand moderate, but significant, binding to skeletal muscle was shown. Similar results were found using an ELISA. Binding of [125I]anti-Tg-Tg complexes of [125I]Tg to thyroid and eye muscle membranes was not affected by the presence of normal human serum, phosphate ions, pH, or incubation temperature, conditions claimed by others to be critical for Tg and Tg-anti-Tg immune complex binding. Since Tg is not present in normal human eye muscle a major role of Tg, or Tg-anti-Tg immune complexes, in the pathogenesis of Graves' ophthalmopathy appears to have been excluded by these findings.
Animals↗
Graves ophthalmopathy: MR imaging of the orbits.
Thirty-nine patients with Graves ophthalmopathy were examined with magnetic resonance (MR) imaging at 0.5 T with use of a surface coil. T1- and T2-weighted spin-echo images were obtained, and T2 relaxation times of eye muscles and retrobulbar fat were calculated from a multiecho sequence. Normal values for T2 relaxation times of eye muscle were obtained by examining nine control subjects. MR imaging demonstrated eye muscle enlargement in 23 patients. Visual examination of T2-weighted and calculated T2 images showed areas of high signal intensity in enlarged eye muscles of 12 of 23 patients. Calculated T2 relaxation times of eye muscles differed significantly between control subjects and patients with stage III and IV disease. Signal intensity characteristics of these changes, as well as their correlation with well-known histologic findings, suggested their interpretation as edema caused by acute inflammation. Since computed tomography is not able to depict eye muscle edema, the MR findings of structural changes within enlarged eye muscles might have an impact on therapeutic decisions concerning the application of anti-inflammatory drugs.
Adult↗
Genetic improvement in beef cattle using a progeny testing system based on carcase merit.
A progeny testing system to measure beef carcase merit, the Abtech Test, has been developed. Nine carcase characteristics are measured objectively at a slaughter age of 300 days on the carcases of 12 steer progeny per sire. Five carcase characteristics were used to quantify the carcase, namely, carcase composition as submitted, carcase composition (adjusted to 20% total carcase fat), estimated lean meat yield (adjusted to 20% total carcase fat), muscle-bone ratio (adjusted to a common muscle plus bone weight), and eye muscle volume index (adjusted for total carcase muscle weight). Four carcase measurements used to describe quality were evaluated: eye muscle area at the 10th rib (adjusted for total carcase muscle weight), marbling of the eye muscle at the 10th rib (chemically determined and adjusted to 20% total carcase fat), muscle texture at the 10th rib (mean muscle bundle diameter) and fat colour (determined on intermuscular fat at the 10th rib under standard conditions). It is proposed that this testing system could be used for the genetic improvement of beef carcases.
Animals↗
[MR relaxation time measurements with and without selective fat suppression (SPIR) in endocrine orbitopathy].
PURPOSE: To determine the value and utility of relaxation time measurements with magnetic resonance (MR) imaging in patients with Graves' ophthalmopathy (G.O.). MATERIALS AND METHODS: 20 orbits were studied in control subjects and 58 orbits in patients with G.O. T2 relaxation times of extraocular muscles and retrobulbar fat tissue were calculated. The thickness of the eye muscles was correlated with the calculated T2 times. 18 orbits were measured before and after retro-orbital radiation therapy. RESULTS: Upper limits of determined normal T2 values were 60 ms in extraocular eye muscles and 40 ms in retrobulbar fat tissue. 89% (17/19) of the patients with G.O. had prolonged T2 times in extraocular eye muscles. The retrobulbar fat tissue in 5 of 38 orbits revealed minimal edema with the use of fat saturated sequences. T2 relaxation times decreased significantly (p < 10(-4)) after 10 Gy radiation therapy. No correlation was found between enlargement and T2 relaxation times in extraocular eye muscles (r = 0.44 in patients before radiation therapy). CONCLUSION: In patients with G.O. the determination of the enlargement of extraocular eye muscles in computed tomography is not a sufficient parameter for an antiinflammatory therapy, since CT cannot visualise eye muscle edema. T2 relaxation time measurements with MR imaging allow differentiation between edematous and fibrotic changes. This is the diagnostic method of choice in patients with Graves' ophthalmopathy.
Adipose Tissue↗
Thyroid Eye Disease.
The treatment of thyroid eye disease is very complex, owing to the varied nature of the symptoms and the variable course of the disease. The first step in treatment should be achieving an euthyroid state or monitoring for the development of hyperthyroidism if the patient is euthyroid at presentation. The second step is local measures (artificial tears and ointment, cessation of smoking) along with careful visual follow-up (acuity, color vision, automated visual fields, fundus examination, ocular motility, and external examination) to assess for the development of optic neuropathy, proptosis, diplopia, and lid abnormalities. If external irritation or orbital discomfort cannot be managed with conservative local measures, then a trial of oral corticosteroids or orbital radiation can be considered. If optic neuropathy develops without proptosis, corticosteroids--starting with an intravenous course, then oral medication--should be used. If there is either an initial improvement in optic neuropathy with corticosteroids, but worsening with subsequent tapering of corticosteroids or no initial improvement, radiation treatment or orbital decompression can be done. If optic neuropathy develops with proptosis, corticosteroids--starting with an intravenous course, then oral medication--should be used for rapid visual improvement. Orbital decompression should then be done to resolve both the optic neuropathy and the proptosis. If for medical reasons the patient with optic neuropathy and proptosis is not a surgical candidate, then radiation treatment can be done, but there will be little change in the proptosis. Proptosis without optic neuropathy can be treated with orbital decompression both for cosmetic reasons and for comfort. Occasionally, this will also resolve lid retraction, and return the lids to an acceptable position in terms of cosmesis and corneal exposure. Diplopia is best treated initially with press-on prisms or patching. Once the disease is stable (ie, no variation in proptosis or change in ocular motility measurements for at least 6 months), eye muscle surgery can be planned. Eye muscle surgery should follow orbital decompression because there is a reasonable possibility that decompression will change ocular motility. If there is corneal exposure or unacceptable lid position and proptosis is not an issue, eyelid surgery, at times on both upper and lower lids, can be done. Eyelid surgery should follow eye muscle surgery because a change in eye position, particularly with vertical muscle surgery, can change eyelid position. Finally, the patient should be made aware at the time of diagnosis that there is unlikely to be a return to normal appearance (ie, appearance before the development of thyroid eye disease).
Journal Article↗