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Biomedical subjects

S Awaya

Publications and source records attributed to S Awaya.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Lateralization in dissociated vertical deviation with flash visual evoked potentials].

Lateralization, suggesting misrouting of optic nerve fibers in albinism, was examined by the flash visual evoked potentials (flash VEP) test in dissociated vertical deviation (DVD). Eighteen cases of DVD were studied and compared with 5 cases of X-recessive ocular albinism and 4 normal controls. Full-field monocular and binocular stimulation was employed with electroencepharograph electrodes on O1 and O2 (10/20 system), and the latency of P100 was statistically analysed with two-way analysis of variance. The difference in the P100 latency between contralateral and ipsilateral stimulation was significant (p < 0.05) in albinism, but not in DVD and normal controls. Therefore, DVD is probably not associated with misrouting of optic nerve fibers.

Adolescent↗
PubMed1995

Amblyopia.

Although the studies of amblyopia, especially the amblyopiogenic factors, symptomatology, terminology, and classification have been well clarified both in clinical aspects and in animal models, detailed pathophysiological mechanisms and psychophysical symptoms have still remained nuclear in many respects. As von Noorden (Helveston et al., Symposium on strabismus: Transactions of the New Orleans Academy of Ophthalmology, St. Louis: CV Mosby; 1978: 1-9) mentioned, the complexity of the amblyopia syndrome is symbolized as an iceberg and reduced visual acuity is the most tangible of many disturbances of visual function. This past year, several articles on amblyopia were published in many journals, and the authors review these articles which are grossly classified into three categories: 1) pathophysiology; 2) symptoms, examinations and diagnosis; and 3) treatment.

Amblyopia↗
PubMed1995

[Effect of tilting on cyclodeviation in nine diagnostic positions of gaze in normal subjects with Awaya's New Cyclo Tests].

We measured cyclodeviation in all nine diagnostic positions of gaze in normal subjects with the New Cyclo Tests and phase difference haploscope. Measurements with the New Cyclo Tests were carried out in the upright posture, and head tilt 15 or 30 degrees to the right or left. Measurements with the phase difference haploscope were carried out in the upright posture with or without the fusional background. Cyclodeviation in all nine diagnostic positions of gaze measured with the New Cyclo Tests in the upright posture was similar to that measured with phase difference haploscope under the fusional background. Both tests showed that excyclodeviation was significantly greater in upward, right-upward and left-upward gaze than in the primary position. It is concluded that cyclodeviation measured with the New Cyclo Tests is not affected by cyclophoria. The amount of excyclodeviation measured with New Cyclo Tests showed no difference between head tilt postures. We suggest that the effects of head tilting on cyclodeviation could be compensated by the corresponding effect on cyclotorsion of both eyes in normal subjects.

Adult↗
PubMed1995

Posterior tenotomy of the superior oblique at the scleral insertion for A-pattern deviations.

A posterior (two-thirds) tenotomy of the superior oblique at the scleral insertion spares the anterior fibers whose action is primarily torsional and can avoid some complications such as cyclovertical diplopia or torticollis, which may be induced by a superior oblique tenotomy or a recession for A-pattern deviations associated with superior oblique overaction (SOOA). A retrospective review was performed of 11 cases with A-pattern, aged 5 to 51 years, who underwent the posterior tenotomy. The average preoperative A-pattern was 18.3 prism diopters and the posterior tenotomy resulted in 16.3 prism diopters of reduction in the A-pattern. There was a good coefficient of correlation between the preoperative amount of A-pattern and the obtained reduction in it (P < 0.001). SOOA was graded on a 9-point system. The average SOOA score of our cases was reduced from +2.77 to +0.77 after the surgery. None of the cases showed worsening of stereoacuity or cyclodeviation. The posterior tenotomy is a simple and effective procedure to correct mild to moderate A-pattern deviations with SOOA.

Adolescent↗
PubMed1995

[Visual functions of dominantly inherited juvenile optic atrophy].

Visual functions including color vision and spectral sensitivity were investigated in 18 of 36 patients and in 2 persons with normal visual acuity in 8 families with dominantly inherited juvenile optic atrophy. Seven of the 8 families had at least one member who showed mainly acquired blue-yellow color vision deficiency. However, only 4 patients showed typical blue-yellow color vision deficiency, which suggested nonspecific characteristics of color vision deficiency in optic neural diseases. One family showed mainly acquired red-green color vision deficiency. Spectral sensitivity functions measured in 5 patients of 3 families showed sensitivity loss in the middle and long wavelength range as well as markedly decreased sensitivity in the short wavelength range. Decrease in spectral sensitivity in the short wavelength range or minimal blue-yellow color vision defect in a subject's brothers with normal visual acuity is interesting, but further study is needed because blue sensitivity decreases easily in various conditions.

Adolescent↗
PubMed1995

Studies on development of visual acuity in infants measured by the Teller Acuity Cards.

In order to confirm the reproducibility of visual acuity measurements in infants and to elucidate the cause of the plateau and decrease in the developmental curve between the ages of 9 and 15 months, we have retrospectively studied visual acuity measured by the Teller Acuity Cards (TAC) in infants aged 2 to 28 months. The visual acuity measured by TAC was higher than that obtained by the conventional preferential looking (PL) method in infants until the age of 14 months. No statistically significant difference was observed between the first eye and the second (fellow) eye measurements. Although monocular visual acuity decreased in infants aged from 9 to 12 months, binocular visual acuity showed an increase in the same age group. The first binocular measurement was better than the last binocular measurement on the same day. Although the first binocular measurement showed an increase in infants aged from 9 to 15 months, the second binocular measurement decreased in the same age group. Our results suggest that all these phenomena mentioned above are likely to be due to the psychological or behavioral rejection to the examinations.

Child Development↗
PubMed1995

Immunoelectron microscopic localization of decorin in aged human corneal and scleral stroma.

Decorin is one of the major proteoglycans in corneal and scleral stroma. Since the distribution of decorin in the normal human eye has not been fully investigated, we examined its immunoelectron microscopic localization in aged human corneal and scleral stroma using anti-decorin antiserum and gold particle-conjugated secondary antibody. In the corneal stroma, decorin was located on the surface of collagen fibrils, on interfibrillar type VI collagen filaments and on dark cross-bands of long-spacing collagen which occurred in the aged human corneal stroma. In the scleral stroma where the banding pattern of D-periodic collagen fibrils was clearly observed, decorin was located on the surface of D-periodic collagen fibrils, chiefly on the d (XI) and e (IX, X) bands, and also on interfibrillar amorphous materials of moderate density which were labeled with anti-type VI collagen antiserum.

Aged↗
PubMed1994

Glycosaminoglycan and collagen fibrillar interactions in the mouse corneal stroma.

When sections of mouse corneal stroma were treated with 20 mM adenosine 5'-triphosphate (ATP) in phosphate buffered saline, pH 4.0, at 37 degrees C and observed by electron microscopy, numerous periodic fibrils with about 100-nm periodicity appeared which were the aggregated form of type VI collagen (type VI collagen fibrils). They occurred in close association with D-periodic fibrillar collagens (striated collagen fibrils). However, when the tissue was digested with chondroitinase ABC or testicular hyaluronidase prior to the ATP treatment, type IV collagen fibrils were segregated from striated collagen fibrils, even though the type VI collagen fibrils themselves aggregated to form the 100 nm-periodic structures. Keratanase or Streptomyces hyaluronidase had no such effect. One possible suggestion is that the ATP-aggregated type VI collagen fibrils are connected with striated collagen fibrils through chondroitin/dermatan sulfate glycosaminoglycans.

Adenosine Triphosphate↗
PubMed1994

Early retinal involvement in mitochondrial myopathy with mitochondrial DNA deletion.

BACKGROUND: Mitochondrial DNA (mtDNA) deletions have been reported in types of mitochondrial myopathy, including Kearns-Sayre syndrome (KSS). We examined mtDNA, skeletal muscle findings, and retinal electrophysiologic function in a patient believed to have incomplete KSS with ptosis and characteristic (so called salt and pepper) retinopathy, but without limitation of ocular motility and without other involvement of the central or peripheral nervous system. METHODS: Muscle biopsy specimens were examined by Gomori trichrome stain and electron microscopy. DNA extracted from muscle was examined by Southern blot analysis. Deleted mtDNA was sequenced by direct sequencing with polymerase chain reaction (PCR). Electroretinograms (ERG) and electrooculograms (EOG) were performed for electrophysiologic examination of the retina. RESULTS: There were no ragged red fibers in skeletal muscle specimens, although abnormal aggregation of mitochondria was observed on electron microscopic examination. An mtDNA deletion was detected. It spanned 5266-bp between the tRNASer gene and the ND5 gene. Electroretinographic and electrooculographic findings were normal, although extensive involvement of retinal pigment epithelium was observed on ophthalmoscopic examination. CONCLUSION: Detecting mtDNA deletion is more critical in diagnosing an incomplete phenotype of mitochondrial myopathy than is morphologic examination. We found that ophthalmoscopic fundus abnormalities preceded abnormalities on ERG and EOG.

Base Sequence↗
PubMed1994

[Studies on the effect of checkerboard pattern on sensory and motor fusion].

We studied the fundamental effects of checkerboard pattern (CP) as fusional background on sensory and motor fusion to clarify the effectiveness of the checkerboard pattern stimulator (CPS), which clinically accelerates anti-suppression and bifoveal fusion in the treatment of manifest strabismus. We studied the size of CP which could generate motor fusion in order to eliminate artificial deviations induced by various powers of prism in Aulhorn's phase difference haploscope, with 20 normal subjects aged from 26 to 30 years old. Seven kinds of check sizes from 0.125 to 5 cycles/degrees (c/d) were presented. We found that a check size of 0.5 c/d or more (narrower check size) had no effect on horizontal motor fusion and that a check size of 1 c/d or more had no effect on vertical motor fusion. To remove suppression, it is important to produce only sensory fusion with the CP. Assuming that the lower limit of visual acuity for CPS is 0.05, the check size needs to be maintained approximately at 1.5 c/d. Our results suggest that a check size of 0.5 c/d for CPS is appropriate to promote sensory bifoveal fusion and stereopsis.

Adult↗
PubMed1994

[A case with stereopsis following early surgery for unilateral congenital cataract].

We report a case of stereopsis following early surgery for congenital monocular cataract. The patient was a 3.75-year-old girl who underwent early surgery for congenital monocular cataract at the age of 19 weeks and received an immediate gas-permeable hard contact lens fitting and occlusion therapy consisting of daily patching the sound eye for 6 hours. During the subsequent years, patching was increased to 50% to 80% of the waking day. Three years and two months postoperatively, she showed good visual acuity of 0.7 in the operated eye and also demonstrated stereoacuity of 1200 to 1500 seconds of arc in the Lang Stereotest or the TV-Random Dot Stereo test, duplicatably. From recent reports with excellent results of stereopsis, including this, we conclude that stereopsis is obtainable in patients undergoing congenital monocular cataract extraction by the end of month 2, contact lens fitting with a good compliance, and a progressive regimen of part-time occlusive therapy not to exceed 80% of the waking time.

Cataract↗
PubMed1993

Histological examination of chick embryos with ocular hypoplasia.

From so-called "dead-in-pipped-eggs" provided by the Poultry Breeding Center of Gifu Prefecture, we obtained two chick embryos with hypoplastic eyes on external examination, and studied the visual system and cranial nerve nuclei innervating the extraocular muscles. The upper bills of both embryos deviated toward one side when observed with the naked eye. In histological sections from the most severely affected eyeball of each case primordial retinal tissue in the poorly developed orbit seemed to be at the stage of optic vesicle formation; it had not differentiated into individual layers. The optic nerve was absent from these eyeballs and the neural retina had multiple folds. The ciliary ganglion was smaller on the more severely affected side than on the contralateral side which had only mild hypoplasia. The optic nerve, which was present on the contralateral side, bifurcated at the level of the chiasma close to the diencephalic base; one branch ran toward the ipsilateral optic tectum and the other toward the contralateral brain region. The oculomotor and trochlear nerve nuclei could be identified bilaterally in one of the embryonic brains but not in the other. These findings suggest that hypoplasia of the neural retina and optic nerve in an orbit leads to bifurcation of the contralateral optic nerve which, under normal conditions, should completely cross at the chiasma. This may also suggest that retinal afferents from the brain are also affected in the hypoplastic eyeball.

Animals↗
PubMed1993

[A study of brain temperature in patients with severe head injuries].

The significance of brain temperature was investigated in patients with severe head injuries. In thirty patients in a state of coma due to severe head injury (Glasgow coma scale of less than 8), brain temperature (Tb), rectal temperature (Tr), and intracranial pressure (ICP) were measured. In 21 out of these patients, cerebral blood flow (CBF) was measured by means of transcranial Doppler effect (TCD), and pulsatility index (PI) was calculated from TCD findings. The outcome was assessed by the Glasgow outcome scale (GOS) 1 month after the head injury. The patients were classified into 4 groups according to the differences (delta T) between Tb and Tr. Group I (11 patients) was defined as always having a higher Tb than Tr, Group II (14) as always having a higher Tr than Tb, Group III (3) was as having no significant differences between Tb and Tr, and Group IV (2) was as having delta T change from plus to minus or from minus to plus during the course of monitoring. As regards the intracranial lesions, no significant differences among these groups were recognized. P.I, at 6 hours after operation, was 1.1 +/- 0.1 (N = 10) in Group I, and was 3.4 +/- 1.9 (N = 9) in Group II. The difference between these two values was statistically significant. The outcome of Group I was better than that of the other groups. The brain temperature is thought to reflect the CBF in the human brain.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Cranial metastasis of hepatocellular carcinoma in a female--case report.

A 78-year-old female presented with swelling and severe pain in the left forehead secondary to a simple head injury received 1 month previously. On admission, neurological examination was normal. Plain skull x-ray films and computed tomography showed an osteolytic and well-defined mass in the left frontal bone. Bone scintigraphy showed high-uptake areas in the right lower ribs and fifth lumbar vertebra. Blood tests showed slight liver dysfunction and a high alpha-fetoprotein level. Abdominal computed tomography showed a huge mass within the liver. Left common carotid angiography disclosed the enlargement of several feeding arteries arising from the external carotid artery with tumor staining. The bone tumor was removed for histological diagnosis and to reduce the localized pain. The histological diagnosis was a cranial metastasis from hepatocellular carcinoma. She died of ruptured varicose veins of the esophagus approximately 8 months after surgery. Surgery for cranial metastasis from hepatic cancer is only indicated when localized pain or hemorrhage threaten the quality of life.

Adult↗
PubMed1993

Long-spacing collagen in the human corneal stroma.

An electron microscopic observation of a corneal lenticule removed 14 months after epikeratoplasty because of refractive error and an unused lenticule was carried out to determine the presence of long-spacing collagen. In the removed lenticule, long-spacing collagen, which is often described as the product of the keratocytes migrating from the host corneal stroma, was observed near a keratocyte. However, long-spacing collagen was also observed in the unused lenticule. In this specimen, keratocytes had been destroyed by freezing so that the secretion of long-spacing collagen by keratocytes should have been negligible. Thus, it seemed that long-spacing collagen could exist naturally in the corneal lenticule as well as be newly formed by migrating keratocytes. In addition, we examined four corneas from patients ranging from 2 months to 91 years of age with no past history of corneal diseases or disorders. Long-spacing collagen was seen in the corneal stromas of the aged persons, but not in those of the younger. In the corneas of the 78-year- and 91-year-old, a different appearance from the usual long-spacing collagen was also seen in the collagen fibrils which showed a slightly shorter periodicity resembling experimentally formed 100 nm periodic fibrils in mice. Long-spacing collagen is a common component of normal human corneal stroma and its occurrence seems to correlate with the age-related changes of the tissue.

Aged↗
PubMed1993

Changes in nystagmus after simultaneous surgery for bilateral congenital cataracts.

The presence of nystagmus has been considered as an indicator of poor prognosis in infants with bilateral congenital cataracts. However, of the 10 infants with preoperative nystagmus reported in this study, after simultaneous surgery for bilateral congenital cataracts, 5 cases showed a resolution of nystagmus or reduction to latent nystagmus postoperatively. This study was carried out to clarify what factors resolved or reduced the preoperative nystagmus. Those 5 cases in whom nystagmus was ameliorated postoperatively were operated on within one month after the onset. Age of nystagmus onset, age at surgery or type of cataract did not affect this amelioration of nystagmus. In contrast, the 5 cases who had no postoperative change in nystagmus were operated on later than this period. Our results demonstrate that it is possible to resolve or reduce preoperative nystagmus in bilateral congenital cataracts by a simultaneous bilateral lens removal within one month after the onset of nystagmus.

Cataract↗
PubMed1993

[Plasma intramembrane structure of overaction of the inferior muscle in humans].

We used the freeze-fracture method to compare the intramembrane structure of the plasma membrane in inferior oblique (IO) muscles from six strabismus patients with normal IO muscles. Inferior oblique myectomy provided us with small pieces of IO muscle from three patients with superior oblique paresis, and from one patient each with V-pattern exotropia, V-pattern esotropia, and V-pattern intermittent exotropia. Samples of normal IO muscle were obtained from two men, aged 33 and 73 years, within 24 hours of their death. The excised muscles were separated at their belly part into orbital and global layers, and small bundles of muscle fiber were fixed and freeze-fractured. The size of intramembrane particles (IMPs) did not differ significantly between normal and strabismus-affected specimens (mean: 9.5 nm). The density of IMP in the 33-year-old man's sample ranged from 800 to 3300/microns2 with a mean of 1823/microns2, in the 73-year-old man's sample ranged from 100 to 2500/microns2 with a mean of 670/microns2, while in the affected tissues it ranged from 100 to 1000/microns2 with a mean 500/microns2. There were no significant differences in caveola size and density between normal and strabismus-affected IO muscles.

Adult↗