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At least 19 recordsLinked to original sources
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[Ultrastructural study of the oculomotor muscle in 2 familial cases of Steinert's disease].

A biopsy specimen of an extra-ocular muscle from a brother and sister affected by typical familial Steinert's disease was examined by electron microscopy. Considerable disorganisation of the contractile element was observed with a gross accumulation of abnormal mitochondria. This was a very different appearance to the findings observed in skeletal muscle in Steinert's disease and much closer to the findings in skeletal muscle in certain 'ocular' myopathies. One cannot fail to be impressed by the discordance between the appearance of the muscular disorganisation and the rarity of clinical oculomotor disturbances in this disease.

Female↗
PubMed1992

[Stilling Duane syndrome and MRI: 2 preliminary results].

Dynamic mode magnetic resonance imaging (DMMRI) allows good visualization of the oculomotor muscles and allows their dimensions to be measured both when they contract and when they relax. The accuracy of this method has been checked and the measurements of the cross section of medial and inferior recti and of superior obliques can be considered to be valid. Measurements of length are inaccurate and the other muscles are not perpendicular to the sectional planes generally used in MRI of the head. By means of a fixation scale situated in the tunnel of the machine, the maximum diameter of medial recti in their thickest part was evaluated in two girls affected by a Stilling Duane retraction syndrome of the left eye. Two direction of the gaze were explored: 25 degrees at the right, then 25 degrees at the left, these angles being obtained by the fixation of particular points of the tunnel scale. The measurements have been made on axial sections, then on coronal sections, both medio-orbital and apical. The first finding is that the diseased medial rectus is much bigger than the healthy one. When relaxed, its thickness is about the same as that of the contracted normal muscle. Coronal orbital cross sections clearly show recession of the belly of the diseased muscle towards the back of the orbit. When contracted it stays in the apical plane and when relaxed in the medio-orbital plane. Lastly the relaxation is much weaker for the pathological muscle than for the healthy one.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1977

Chronic progressive external ophthalmoplegia in a heredo-ataxia: neurogenic or myogenic? A clinical, neuropathological and submicroscopic study.

A patient with Friedreich's disease and chronic progressive external ophthalmoplegia is descirbed. An investigation was performed into the nature of the ocular motor disorders, which appeared clinically to be supranuclear. The EMG of the ocular muscles suggested myopathy. A specimen of ocular muscle was obtained by biopsy and examined with the light microscope and-for the first time-under the electron microscope. Signs of mitochondrial myopathy were found alongside neurogenic features. Postmortem examination of the central nervous system confirmed the diagnosis of Friedreich's disease with lesions of the motor cells in the anterior horn of the spinal cord. No evidence was found for a supranuclear or inernuclear origin of the ocular palsies, but 20-30 per cent of the neutrons in the nuclei III and IV were atrophic. Lesions of the non-medullated motor nerve fibres were also visible under the electron microscope. That the origin of the c. p. e. o. in this heredo-ataxia is neurogenic-nuclear is postulated on the grounds of the neuropathological and electronmicroscopic findings. Resemblances to the microscopic and submicroscopic and submicroscopic appearance of many types of "ocular myopathy" and "ophthalmoplegia-plus" throw doubt upon the myogenic character of these conditions. Possibly chronic, slowly progressive atrophy in the nuclear areas of the ocular motor nerves must in these cases also be held responsible for the c. p. e. o. Perhaps Moebius's Kern-Schwund theory may be revived after 85 years.

Adult↗
PubMed1978

Proprioceptive afferent fibers in the cranial nerves III, IV and VI.

The purpose of the present works was to clarify whether the cranial nerves III, IV and VI carry proprioceptive afferent fibres from the extrinsic ocular muscles. In sheep the picture is now clear. The cranial nerves III, IV and VI carry many large proprioceptive fibres (12-16 micrometer) to the central nervous system. These nerves also contain many small fibres of the y-range (2-6 micrometer) which innervate the intrafusal muscle fibres in the spindles. In man the picture is still vague: most of the spindles are not typical, the large proprioceptive fibres (12-16 micrometer) and the small y-fibres (2-6 micrometer) are very few in the cranial nerves III, IV and VI. It is to be concluded that in sheep the cranial nerves III, IV and VI are not purely motor nerves to the extrinsic ocular muscles, but they also carry many of the large fibres of the proprioceptive function. In man, such large fibres are not found and the pathway of proprioceptive afferents from the orbital muscles is still not certain.

Abducens Nerve↗
PubMed1978

The localization of the motor neurons innervating the extraocular muscles in the oculomotor nuclei of the cat and rabbit, using horseradish peroxidase.

The localization of the motor neurons innervating the extraocular muscles in the oculomotor nuclei of adult cats and rabbits was investigated by means of retrograde labelling with horseradish peroxidase (HRP). The groups consisting of the motor neurons innervating an individual muscle lay in the nucleus as elongated columns extending in a longitudinal direction. The position of each group in the transverse section varied according to the rostro-caudal level of the nucleus. In the cat and rabbit, entire contralateral innervation of the superior rectus and entire ipsilateral innervation of three muscles of the inferior rectus, medial rectus and inferior oblique were similarly observed. However, the arrangement of individual motor groups differed considerably in both animals except for the group innervating the inferior rectus which was generally found in the ventral position running through the rostral two-thirds of the oculomotor nucleus. In the case of cats, the central caudal nucleus bilaterally innervated the levator palpebrae superioris. The motor neurons innervating this muscle in the rabbit (which lacks the central caudal nucleus) formed a rostro-caudal club-shaped column close to the group innervating the superior rectus. The aberrant cellular mass in the adjoining medial longitudinal fasciculus which belongs to the medial rectus appears to play an important role in the eye movement, because it commonly appears in various animals.

Animals↗
PubMed1978

Histochemistry of human extraocular muscle.

A reliable method for evaluating biopsy specimens of human extraocular muscles is presented to better understand the pathological responses of these highly organized striated muscles. Three muscle fiber types and their distribution are described with morphological and histochemical measurements used commonly for limb muscle. The granular and fine fibers have single end plates and may be comparable to limb-twitch fibers (type 2 and type 1 fibers). The coarse fibers have multiple end plates and may correspond to multiple end plated tonic fibers found in avian and amphibian limb muscles. The fibers of extraocular muscles are arranged in three concentric zones. Because of the zonal arrangement, a complete cross section should be evaluated in diseases of the ocular muscles to estimate any changes in fiber type distribution.

Adult↗
PubMed1977

An electrooculographic study of internuclear ophthalmoplegia.

The eye movements of 25 patients with internuclear ophthalmoplegia were recorded by electrooculography. The velocity of adducting saccades was markedly less than normal. The velocity of abducting saccades was within the normal range, but statistically there was a wider distribution. Recordings were made in 2 patients several months after the onset of internuclear ophthalmoplegia, at which time the adducting eye velocity was greater than the abducting eye velocity. A patient with a unilateral medial fasciculus lesion showed marked overshoot of the abducting eye on contralateral saccades and overshoot of both eyes toward the side of the lesion. Optokinetic and postcaloric nystagmus were recorded, and the slow phase showed increasing velocity exponential waveform for the abducting eye. The recordings also showed decreasing velocity exponential waveform for the abducting eye. Downbeat nystagmus was as common as upbeat nystagmus in our patients. The findings appear to confirm the theoretical analysis of the eye movement disorder in internuclear ophthalmoplegia provided by Pola and Robinson as modified by recent experimental work in primates.

Brain Ischemia↗
PubMed1979

Extraocular muscle biopsy in chronic progressive external ophthalmoplegia.

A quantitatives assessment of the pathological changes in extraocular muscle is presented in 8 patients with chronic progressive external ophthalmoplegia (CPEO). Serial cross-sections of extraocular muscle were stained with a battery of histochemical and immunohistochemical techniques and compared with 36 normal extraocular muscles and 1 muscle from a patient who had longstanding third nerve plasy with anomalous reinnervation. Several of the patients had a striking increase in the number of ragged-red fibers in extraocular muscle, particularly if frequent ragged-red fibers also were found on limb muscle biopsy. One patients demonstrated extrajunctional acetylcholine receptor (AChR) in a small percentage of fibers, although this finding was not present in the reinnervated muscle. Numerous darkly staining central regions were noted in the ocular muscle fibers of a patient with Stephens syndrome (CPEO, peripheral neuropathy, and cerebellar disease) and in the reinnervated muscle. A patient with myotubular myopathy had single central nuclei in both limb and ocular muscle. All patients demonstrated in their extraocular muscles variation in both the size and distribution of each of the three histochemical fiber types. Extraocular muscle biopsy proved to be a safe, reliable technique. As a similar quantitative analysis is applied to the study of further patients, a better understanding of the pathogenesis of CPEO should be possible.

Adolescent↗