External Eye Muscles Research Articles

ODP332 Maternal Central Diabetes Insipidus Immediately after Delivery, Owing to Vasospasm of the Internal Carotid Artery

Abstract Background Sheehan's syndrome is a cause of hypopituitarism during the postpartum period, but it rarely manifests immediately after birth. Clinical Case We report the case of a 30-year-old woman who delivered her second child, lost 1,050 mL of blood in the process, but did not receive a blood transfusion. A few hours after delivery, the patient complained of headache, nausea, and thirst, and her urine production increased to 9 L/day. No menstrual irregularities or abnormalities during pregnancy or childbirth had been reported. None of hypotension, external eye muscle paralysis, or visual impairment were identified on physical examination. The laboratory findings were low urine osmolality and high serum osmolality and sodium concentration. The concentrations of thyroid hormones, growth hormone (GH), and anti-diuretic hormone (ADH) were found to be low. The IgG4 concentration was not high (4.7 mg/dL; normal <105 mg/dL) and the patient was negative for anti rabphilin-3A antibody. Pituitary magnetic resonance imaging (MRI) on the day of admission showed enlargement of the pituitary gland and stalk, and magnetic resonance angiography showed stenosis of the left internal carotid artery. The patient showed a poor response to GH-releasing peptide 2 and thyroid releasing hormone stimulation. Hypertonic saline administration did not cause an increase in ADH concentration. We diagnosed adult growth hormone deficiency (aGHD), central hypothyroidism, and central diabetes insipidus (DI). The enlargement of the pituitary gland was slightly less marked and the stenosis of the left internal carotid artery improved 7 days after admission. After 6 months, the pituitary gland was almost normal in size, although the aGHD, central hypothyroidism, and central DI remained. Sheehan's syndrome or lymphocytic hypophysitis could have been responsible for the postpartum hypopituitarism. This case was not typical of lymphocytic hypophysitis with respect to the hormone deficiency pattern, the MRI findings, and the lack of anti rabphilin-3A antibody. Sheehan's syndrome is caused by ischemic necrosis of the anterior pituitary gland after severe postpartum hemorrhage. The prevalence of central DI is estimated to be 2%–3%. Typically, pituitary dysfunction progresses slowly and develops several years after childbirth. In contrast, in the present patient, stenosis of the left internal carotid artery developed and improved during short periods of time. The vasospasm of the internal carotid artery caused reductions in flow through the superior and inferior hypophysial arteries, which resulted in ischemia and necrosis of the pituitary gland, similar to Sheehan's syndrome. Clinical Lesson: Although rare, maternal central DI can be caused by ischemia and vasospasm immediately after the delivery of a child. The possibility of a pituitary stroke in the presence of neoplastic disease should not be ruled out, and imaging and pituitary gland function should be followed over the long term. Presentation: No date and time listed

Letter to the Editor Complex-I defect with minimal manifestations

Letter to the Editor Complex-I defect with minimal manifestations

P4.61 Prominent respiratory muscle involvement in adPEO with POLG1 mutation

Progressive external ophthalmoplegia (PEO) is characterized by multiple mitochondrial DNA deletions in skeletal muscle. The most common clinical features include adult onset of weakness of the external eye muscles and exercise intolerance. Additional symptoms are variable, and may include cataracts, hearing loss, sensory axonal neuropathy, ataxia, depression, hypogonadism, and parkinsonism. Both autosomal dominant (adPEO) and autosomal recessive inheritance can occur, and autosomal recessive PEO is usually more severe.

A Single Mutation in Human Mitochondrial DNA Polymerase Pol γA Affects Both Polymerization and Proofreading Activities of Only the Holoenzyme

Common causes of human mitochondrial diseases are mutations affecting DNA polymerase (Pol) gamma, the sole polymerase responsible for DNA synthesis in mitochondria. Although the polymerase and exonuclease active sites are located on the catalytic subunit Pol gammaA, in holoenzyme both activities are regulated by the accessory subunit Pol gammaB. Several patients with severe neurological and muscular disorders were reported to carry the Pol gammaA substitutions R232G or R232H, which lie outside of either active site. We report that Arg(232) substitutions have no effect on independent Pol gammaA activities but show major defects in the Pol gammaA-Pol gammaB holoenzyme, including decreased polymerase and increased exonuclease activities, the latter with decreased selectivity for mismatches. We show that Pol gammaB facilitates distinguishing mismatched from base-paired primer termini and that Pol gammaA Arg(232) is essential for mediating this regulatory function of the accessory subunit. This study provides a molecular basis for the disease symptoms exhibited by patients carrying those substitutions.

Visual Evoked Potentials in Basedow's Ophthalmopathy before and after Orbital Decompression or Retrobulbar Irradiation

VEP are an objective and a more sensitive sign of optical neuropathy in Graves' ophthalmopathy than is visual acuity. A correlation exists between VEP and the changes in the external eye muscles as visualized on CT scans. VEP should always be registered if CT changes are present. Improvement of optic neuropathy as evaluated from VEP seems to be remarkably infrequent.

The role of eye movement in upright postural control

Vision contributes to upright postural control by providing afferent feedback to the cerebellum. Vision is generally classified into central and peripheral vision. In measurements of postural sway, in which participants are required to maintain a stable upright posture while fixating on a visual target, non-retinal eye positional information due to the fixation is used as well as the retinal information from both visual fields. However, little is known about the role of non-visual eye positional information in postural control. This study examined the role of non-visual eye position information in upright postural control by comparing participants’ centre of pressure (COP) sway between two experimental conditions: (1) a space-fixed visual target condition (control), in which eye movement was not controlled, and (2) a head-fixed visual target condition (treatment), in which eye movement was inhibited. Using 12 university students, COP sway and electrooculograms (EOG) were measured under both conditions. In the space-fixed condition, participants maintain an upright posture while fixating on a visual target fixed on a screen 1 m in front of them. In the head-fixed condition, participants maintained an upright posture while gazing at a target moving in sync with their head sway on the screen. The COP was evaluated by path length, area, root mean square, velocity and position. Eye movements were evaluated by the mean eye movement angle. The mean eye movement angle was significantly larger in the vertical direction then in the horizontal direction in both experimental conditions and was also found to be larger in the space-fixed condition than in the head-fixed condition. No significant different was found in any COP parameter between both conditions. It was suggested that non-visual eye position information from the external eye muscles to the sensory perception system contributes little to postural stabilisation under the measurement conditions used in this study.

Strabismus and eye muscle function

Studies of external eye muscle morphology and physiology are reviewed, with respect to both motor and sensory functions in concomitant strabismus. The eye muscles have a more complex fibre composition than other striated muscle, and they are among the fastest and most fatigue-resistant muscles in the body. However, it is not generally believed that concomitant strabismus is due to a primary abnormality of the eye muscles or the ocular motor system. The gross anatomy of eye muscles, including the shape and position of the eye muscle pulleys, was not changed in strabismus. The histology of the eye muscle fibres was also basically the same, but changes have been observed in the cellular and biochemical machinery of the fibres, most notably in the singly innervated orbital fibres. Functionally, this was seen as slower contractions and reduced fatigue resistance of eye muscles in animals with strabismus and defects of binocular vision. Most likely the changes represented an adaptation to modified visual demands on the ocular motor control, because of the defects of binocular vision in strabismus from an early age. Adaptation of eye muscle function to visual demands could be seen also in the adult human ocular motor system, but here the effects could be reversed with treatment in some conditions. External eye muscles in the human have sensory organs, muscle spindles and tendon organs, responding to changes in muscle force and length. It is not known how these proprioceptors are used more specifically in ocular motor control, and there is no stretch reflex in the external eye muscles. However, a clear influence on space localization and eye position can be demonstrated with vibratory stimulation of the eye muscles, presumably activating muscle spindles. Different effects were observed in normal subjects and in adult patients with strabismus, which would indicate that the proprioceptive input from one eye of strabismic patients could be suppressed by the other eye, similar to visual suppression in concomitant strabismus. Such an interaction would most likely occur in the visual cortex, and not in the ocular motor system. Further studies of proprioceptive mechanisms, during the postnatal developmental stage and in adult concomitant strabismus may shed light on the mechanisms of childhood strabismus and may, in this respect, be a more fruitful avenue for further research than eye motor studies.

BRAINCASE OF THE UPPER DEVONIAN SHARK CLADODOIDES WILDUNGENSIS (CHONDRICHTHYES, ELASMOBRANCHII), WITH OBSERVATIONS ON THE BRAINCASE IN EARLY CHONDRICHTHYANS

The braincase of an Upper Devonian shark (Cladodoides wildungensis) is investigated using high-resolution CT scanning, and its internal and external morphology is described from three-dimensional digital reconstructions. Many features are shared with modern elasmobranchs (neoselachians); these mostly represent conserved elasmobranch, chondrichthyan, or gnathostome characters. C. wildungensis resembles neoselachians in having a closed metotic fissure defining a glossopharyngeal canal, unlike some early chondrichthyans (e.g., Pucapampella, Orthacanthus) in which an open metotic fissure extends a considerable distance beneath the otic capsule. However, the glossopharyngeal canal in C. wildungensis is connected to a persistent dorsal fissure between the occipital arch and otic capsules, whereas this fissure becomes closed during neoselachian ontogeny. The embryonic polar cartilage apparently made a much greater contribution to the basicranium than in neoselachians and gnathostomes generally. This has affected the position of the efferent pseudobranchial foramen and the location of the orbital articulation in Cladodoides (both of which are located anteriorly in the orbit), as well as the size and extent of the dorsum sellae and the hypophyseal chamber inside the braincase. Another unusual feature in Cladodoides is the postorbital position of its trigeminal and facial nerves; instead of being situated in a trigemino-facial fossa of the orbit as in neoselachians, their foramina are located behind the postorbital process, although the pituitary vein and the origin of the external rectus eye muscle (located within the trigemino-facial fossa in neoselachians) both lie in the posterior part of the orbit. The oblique orientation of the postorbital arcade (derived from the embryonic lateral commissure) may be related to the exclusion of the trigeminal and facial nerves from the orbit. A laterally oriented canal through the process probably contained the trigeminal maxillary ramus (perhaps accompanied by the buccal ramus of the anterodorsal lateral line nerve). By contrast, in neoselachians these rami pass directly into the orbit (sometimes forming a buccal-maxillary complex), but they do not pass through the postorbital process. The Cladodoides braincase probably represents a juvenile or submature individual and shows indications of incomplete development (e.g., presence of a wide bucco-hypophyseal fenestra and absence of a precarotid commissure; incomplete enclosure of the internal carotids and orbital arteries by basicranial cartilage; incomplete closure of the braincase roof along the dorsal midline). The braincase also lacks multiple-layered prismatic calcification, possibly representing another juvenile feature. The phylogenetic relationship of Cladodoides wildungensis is discussed. Dental, postcranial, and cranial features lend some support to the old hypothesis that cladodont sharks form a monophyletic group. While such a view is at variance with several recently published phylogenetic analyses, many of the characters noted in the present work have yet to be tested within a rigorous cladistic framework, and their phylogenetic significance is uncertain.

Cyclotropia and surgical treatment after macular translocation

Macular translocation is a new surgical treatment method successfully performed in recent years in cases of age-related macula degeneration. Cyclotropia and associated orthoptic problems may occur after macular translocations. The aim of our study was to present the application and results of various external eye muscle surgery techniques to eliminate cyclodeviation after macular translocation. Between January 2001 and April 2001, 15 patients underwent macular translocation. After an average of 47 days counterrotation was applied to these patients to eliminate incyclotropia formed due to macular translocation. In 8 cases, superior and inferior oblique muscle surgery was combined with opposite vertical transpositions of the horizontal recti. In 5 cases, full tendon transposition of the superior oblique muscle to the nasal part of the globe was combined with the anterior margin advancement of the inferior oblique muscle. In 2 cases, only combined surgery of superior and inferior oblique muscles was performed. The degree of cyclodeviation was measured by both objective and subjective methods before and after counterrotation. Mean follow-up period was 53.9 days. The average objective cyclodeviation formed after macular translocation was 29.6 degrees. Combined surgery of superior and inferior oblique muscles led to a mean excyclorotation of 15 degrees whereas combined oblique muscle surgery performed with vertical transposition of horizontal recti provided a mean excylorotation of 20.8 degrees. The most effective method was the combination of total nasal transposition of superior oblique muscle with the anterior margin advancement of the inferior oblique muscle resulting in an improvement by 33 degrees. Macular translocations cause cyclodeviation. The ensuing cyclotropia can be eliminated by various surgical techniques of external eye muscles according to the degree of cyclotropia.

MRI measurements of orbital tissues in dysthyroid ophthalmopathy.

Muscle volume investigation by different imaging techniques has proven useful in the diagnosis and follow up of treatment in dysthyroid ophthalmopathy. However, no study on muscle volume measurement by magnetic resonance imaging (MRI) has been done in this disease. Six patients with monocular or asymmetric binocular dysthyroid ophthalmopathy and eight controls were examined with orbital MRI using a surface coil. In the muscle volume study, 2 mm coronal slices were used for measuring the six extraocular muscles (EOM), i.e., medial rectus (MR), lateral rectus (LR) superior rectus (SR), inferior rectus (IR), superior oblique (SO), and inferior oblique (IO) muscles, as well as the orbital fatty tissue (OFT). In the muscle thickness study, 3 mm transverse and sagittal images were used for measuring the four rectus muscles during fixation in different gaze positions in horizontal and vertical planes. In dysthyroid ophthalmopathy, the muscle volume of the six external eye muscles was significantly larger than in controls, except for the IO. The IR and MR showed the largest increase in muscle volume. The correlation between muscle thickness and different degrees of eye deflections was linear for all four rectus muscles both in patients and controls, and no significant differences in the slopes of the regression lines were found. The volume of OFT was significantly larger in patients than in controls, and the change in volume was larger than that of muscle volume. MRI technique makes it possible to observe and evaluate quantitatively the volume of all six extraocular muscles and the orbital fatty tissue in dysthyroid ophthalmopathy. It also makes it possible to evaluate changes in morphology during eye muscle contraction.

Immunocytochemical localization of mitochondrial single-stranded DNA-binding protein in mitochondria-rich cells of normal and neoplastic human tissue.

Mitochondrial single-stranded DNA-binding protein (mtSSB) is necessary for mtDNA replication. So far the protein has been studied mainly in Escherichia coli and in cell cultures of lower mammals. In this investigation, the authors studied the expression of mtSSB in normal and neoplastic human tissue by light and electron immunocytochemistry. mtSSB has been detected in various tissues and particularly in mitochondria-rich tissues such as external eye muscles and parietal cells of the stomach and in mitochondria-rich tumors (oncocytomas) of various origins. Ultraimmunocytochemistry disclosed the specific distribution of immunoreactive mtSSB over the mitochondria. The staining intensity was heterogeneous. Forty-five percent had a labeling index (silver grains/microm2) greater than 1 and less than 3, approximately 20% had an index of 3 or greater, and 15% of mitochondria remained unstained. The mean labeling index was 1.83. Immunolabeling showed a linear correlation with the mitochondrial profile area (r = 0.82). In conclusion, mtSSB is regularly expressed in normal and neoplastic human tissue of different origin, function, and differentiation. The heterogeneous staining pattern most probably reflects the functional heterogeneity of mitochondria.

Wertigkeit der neuroradiologischen Bildgebung bei der endokrinen Orbitopathie

Aim: CT and MR in the diagnosis and course of Graves’ disease (endocrine orbitopathy) are presented and discussed. Value of CT and MRT: Both methods are able to show exactly the morphological changes, with thickening of the external eye muscles relative to the tendon and the extension of proptosis. MR is additionally able to define – on the basis of T2 measurements – the acuity of the disease, a chronic course with fatty degeneration and muscle fibrosis. Conclusion: The complexity of the disease is an interdisciplinary challenge to all physicians dealing with these patients. Even in times of cost reduction in healthcare the use of CT and MR is mandatory, as it helps to define and control the therapy.

Effect of different anaesthetic regimes on the oculocardiac reflex during paediatric strabismus surgery

The oculocardiac reflex (OCR) is induced by mechanical stimulation and therefore is frequently encountered during strabismus surgery. This study was designed to determine how various anaesthetic regimes modulate the haemodynamic effects of the OCR during paediatric strabismus surgery. Thirty-nine patients (4–14 years, ASA I) were randomized to one of four anaesthetic regimes: group P: propofol (12 mg·kg–1·h–1) and alfentanil (0.04 mg·kg–1·h–1); group S: sevoflurane 1–1.2 MAC in 30% O2/70% N2O; group K: ketamine racemate (10–12 mg·kg–1·h–1) and midazolam (0.3–0.6 mg·kg–1·h–1; group H: halothane 1–1.2 MAC in 30% O2/70% N2O. Electrocardiogram (ECG), beat-to-beat heart rate (HR) and blood pressure (BP) changes were measured during and after a standardized traction was applied to an external eye muscle (4–6 Newton, 90 s). OCR was defined as a 10% change in HR induced by traction. OCR occurred in 77% of patients. Whereas virtually all patients in the P, H and S groups developed OCR, only 22% developed it in group K. Median HR change in group P (–37 bpm) was significantly greater (P < 0.05) than in group H (–17 bpm) or group K (–7 bpm). Median BP change in group K (+10 mmHg) was significantly different (P < 0.05) from group H (–5 mmHg), group S (–3 mmHg) and group P (–8 mmHg). Atrioventricular rhythm disorders were significantly more frequent in group P compared with group K (P < 0.02). Respiration-induced sinus dysrhythmia was significantly less frequent (P < 0.001) in group K (0%), compared with group P (100%), group H (56%) and group S (55%). Of the anaesthetic techniques studied, ketamine anaesthesia is associated with the least haemodynamic changes induced by OCR during strabismus surgery in paediatric patients.

A note on the development of the vestibulo-ocular pathway in the chicken

The vestibulo-ocular pathways have been examined in embryonic chicks using horseradish peroxidase or diI as retrograde and anterograde tracers. The vestibular neurons project to the rostral, external eye motor nuclei over one or the other of three separate pathways; the ipsilateral and contralateral medial longitudinal fascicle and the contralateral brachium conjunctivum. The brachium conjunctivum component originates dorsally in the superior vestibular region and projects to the contralateral inferior oblique and superior rectus motor nuclei. An ipsilateral component of the medial longitudinal fascicle is labeled from more ventral sites in the vestibulo-cerebellar process and terminates in the ipsilateral superior oblique and inferior rectus nuclei. The contralateral medial longitudinal fascicle component originates still more ventrally and terminates in the contralateral superior oblique and inferior rectus motor nuclei. Accordingly, the vestibulo-ocular pathways in chickens operate predominantly on synergistic pairs of external eye muscles. These selective terminal fields are established within a day or two after the first terminals invade the eye motor nuclei during embryogenesis.

Topography and organization of cranial nerve nuclei in the sand lizard, Lacerta agilis.

Cobaltic-lysine complex compound was used to label cranial nerves of the ventrolateral (branchiomotor) and dorsomedial (somatomotor) nuclear columns in the sand lizard, Lacerta agilis. The dendritic arborizations and axonal trajectories of neurons of the respective nuclei were reconstructed from serial sections. A fairly uniform neuronal morphology was found in the nuclei of the ventrolateral column: a spindle-shaped perikaryon gave rise to dorsomedial and ventrolateral dendritic trees, the latter arborizing in a characteristic broomlike manner within a narrow region in the lateral white matter. Axons of all neurons converged upon the medial longitudinal fasciculus and after making a hairpin turn formed the corresponding motor roots. A group of small neurons constituted a separate subnucleus within the V motor nucleus. The VII and IX nuclei were fused into a single nuclear complex. The nucleus ambiguus was found dorsal to the XII nucleus and lateral to the dorsal vagal nucleus. The latter nucleus extended rostrally to the caudal pole of the VI nucleus, and its neurons sent axons to the VII, IX, and X nerves. The term "dorsal visceromotor column" designates the extended dorsal vagal nucleus. A number of small polygonal neurons lying scattered in the lateral part of the medulla were labeled via the VII, IX, and X nerves. This loose aggregate of labeled neurons was termed the "lateral visceromotor area." On the basis of nuclear topography and cellular morphology, the existence of a bulbar XI nucleus was excluded. Three different types of neurons could be distinguished in the dorsomedial nuclear column. Neurons with oval or spherical perikarya and radially oriented dendrites constituted the nuclei innervating external eye muscles. Except for the IV nucleus, axons followed a ventral trajectory. The accessory VI nucleus was composed of a second type of neuron with elongated soma and dorsoventral dendrite orientation; the dorsally directed axon turned ventrally at the VI nucleus. The XII nucleus contains a third type of neuron with strongly decussating dendrites. The distinct differences in the neuronal morphology did not support the classical assumption that all of the nuclei of the dorsomedial motor column supply muscles derived from somitic mesoderm. Sensory fibers of the trigeminal nerve formed the familiar spinal tract, which partially decussated in the medullospinal transition zone and could be followed as far as the lumbar segments on the ipsilateral side of the spinal cord. Neurons of the mesencephalic root of the trigeminal nerve were localized in the optic tectum; their descending fibers joined the medial aspect of the spinal tract.(ABSTRACT TRUNCATED AT 400 WORDS)

Evaluation of extraocular muscles in patients with endocrine exophthalmos before and after treatment

The authors discuss the behaviour of the eyeball motility and the thickness of the external eye muscles in patients with infiltrative ophthalmopathy. the observations covered 22 patients with Graves' disease, being in the state of euthyroidism. Prior to the beginning of therapy and directly after its termination, all patients were subjected to full clinical evaluation, computerized tomography as well as to examination of the range of eyeball movements. A restriction of all movements of the eyeballs was disclosed, the most serious handicap being recorded in the upward movement (6.5 mm), upward and external movement (8.2 mm), upward and internal (8.5 mm). the tomographic estimation revealed restriction of the straight muscles, inferior and superior, on the average by 3.5 mm, medial by 2.5 mm, and of the lateral straight muscles by 0.5 to 1 mm. Glucocorticoids and glucocorticoids together with imuran were used during the treatment. the therapy lasted from four to nine months. Just after the end of the therap...

External eye muscle palsies and atypical retinitis pigmentosa in an adult with cystic fibrosis*

A 30-year-old male with cystic fibrosis and a nine-year history of drooping eyelids, ataxia and night-blindness was studied. Neurological examination disclosed external eye muscle palsies, atypical retinitis pigmentosa, ataxia and diminished vibratory and touch perception in the lower extremities. Activity of lysosomal a-L-Fucosidase in leucocytes and cultured fibroblasts was in the heterozygote range. Sural nerve biopsy showed slight signs of neuropathy but no axonal swellings. At autopsy axonal swellings were found in nucleus gracilis and nucleus cuneatus. It is suggested that the neurological signs and the neuropathological findings are compatible with vitamin E deficiency of long duration.

光眼輪筋反射の late component の発現機序に関する実験的研究

An electrophysiological study was made with rabbits on the electrical changes of photopalpebral reflex (PPR) which were cumulatively recorded by computer. In addition, electroretinogram (ERG), visual evoked response (VER) and photo-evoked eyelid microvibrat ion (MV) were simultaneously recorded.The results o btained were as follows.1.9 components (PPR1, PPR2, PPR3, PPR4, PPR5, PPR8, PPR7, PPR8 and PPR9) were observed in PPR with monopolar lead. In ERG, there were found a wave and 3 oscillating potentials (O1,O2 and O3) on b wave, and 5 components (VER1, VER2, VER3, VER4and VER5) were shown in VER.2. All components of PPR and ERG disappeared when the intraocular pressure was elevated as high as 120-160 mmHg.3. The componen ts of PPR5-9 and VER disappeared after the optic nerve was cut off.4. The components of PPR5-9 disappeared after the brain stem reticular formation (RF) was destroyed.5. All components of PPR showed no appreciable change with 3Hz stimulation on RF, whereas all but PPR1 increased in amplitude with 100Hz stimulation on RF.6. The PPR5-9 increased in amplitude and the PPR6,7,8 de creased after the destruction of the nucleus ventralis anterior (VA).7. The PPR5-9 decreased in amplitude with 3Hz stimulation on VA, but they increased with 100Hz stimulation.8. W hen PPR and MV were recorded simultaneously, MV was found coincidental with the culmination of PPR5-8.9. The ampli tude of PPR5-8 decreased after either the removal of M. orbicularis oculi or the resection of external eye muscles, and they disappeared after the simultaneous resection of both muscles.10. The amplitude of PPR5-9 decreased after the amputation of n. facialis and they disappe ared following additional retrobulbar anesthesia.11. Inhibitory effect was observed on the amplitude of PPR6-8, following the administration of gallamine.12. Barbiturate, chlorpromazine, diazepam and tofranil had inhibitory effect predominantly on all the components of PPR. Whereas cardiazol, when properly given, showed facilitatory effect on PPR5-9. Amphetamine and CDP-choline showed no noticeable effect.13. ERG was not affected significantly with the administration of such chemicals as barbiturate, chlorpromazine, diazepam, tofranil, cardiazol, amphetamine and CDP-choline.14. VER was not affected either with the administration as cardiazol, amphetamine or CDPcholine.15.9 components of PPR were also found in men as well as in rabbits. When a series of photic stimulation was given through one eye and led out of the other shielded eye, the components of PPR1-4 and ERG disappeared, but the PPR5-9 and MV were also recorded. On giving mathematical questions, the amplitude of PPR5-9 and MV increased.Consequently, it was obvious that the early components of PPR (PPR1-4) were closely related to ERG, that the late components of PPR (PPR5-9) had their origin in the central nervous system (especially in RF), that, above all, the components of PPR5-8 were parallel with MV and that the PPR9 was a potential different from MV as well as the secondary response of VER and activated by nervous activities higher than consciousness.

Computed tomography of orbital lesions. A radiological study of 144 cases.

During the first two years with the 160 x 160 matrix EMI scanner 144 consecutive patients referred with suspicion of orbital disease were subjected to 190 computed tomography (CT) examinations. The X-ray attenuation and enhancement patterns of the various lesions were analyzed. In general it was difficult to correlate these parameters with the histopathological features. Hemangiomas, however, showed little enhancement and meningiomas a large degree of enhancement, while malignancies, lymphomas and pseudotumors were mainly intermediate. With orbital Graves' disease a low preinjection attenuation and a large enhancement (with normal striated neck muscle as a reference) was found in the external eye muscles. The diagnostic accuracy of CT (n=143) was compared to that of A/scan ultrasonography (US, n=80) and carotid angiography (n=40). CT showed the highest accuracy of the three methods, but CT differed only statistically from carotid angiography.

Visualization of orbital tissues using various echographic techniques

Abstract Seventeen different ultrasonic A -scan techniques were used for ultrasonography of intact human orbits to find technical parameters which are most suitable to exhibit identifiable echoes from the posterior sclera, the surface of the external eye muscles and the orbital bones simultaneously. Contact coupling of the transducer probes to a number of preselected examination points at the anterior surface of the globe (horizontal plane) was applied to each of the techniques studied. The echograms were compared to an anatomic scheme developed specially for the purpose. The ultrasonic beam was initially directed rectangularly to the opposite sclera; subsequently attempts were made to pick up presumed muscle or bone echoes of higher amplitudes by tilting the transducer slightly within the horizontal plane. The tilting was limited by the requirement to maintain a high scleral echo amplitude. The best echograms were recorded using our modified echograph 7100 MA (Kretztechnik, Austria) with well-defined time-gain compensation and a 6 MHz probe.