Biomedical subjects

S Awaya

Publications and source records attributed to S Awaya.

At least 55 records · Page 3Linked to original sources

PubMed1993

[The relationship between the developmental change in visual acuity measurements and change of refractive error in young infants].

219 normal infants aged 3 to 36 months were tested to investigate the relationship between the development of visual acuity and the change of refractive error. 17 infants were tested over a period of time. Visual acuity was assessed by Teller Acuity Cards (TAC), and refractive error was measured by an infrared video refractor (PR1000) without cycloplegics. The results were as follows. 1) The success rate of both tests in 3 to 6 month-old infants was higher than in infants aged 11 to 14 months and 23 to 36 months. 2) Visual acuity showed a rather slow development in infants aged 3 to 12 months. 3) With-the-rule astigmatism of 1 diopter (D) or more occurred with a high incidence in the 3 to 8 month old infants, and decreased with age. 4) The visual acuity in the infants with astigmatism was no different than in those without it. 5) The slow developmental curve of visual acuity measured in 3 to 12-month old infants was probably the result of psychological aversion to the TAC.

Age Factors↗

PubMed1993

[Inferior oblique underaction].

We investigated the etiology and incidence of 100 cases of inferior oblique underaction. The difference between congenital and acquired underaction was discussed using Awaya's New Cyclo Tests (NCT) to examine cyclodeviation qualitatively and quantitatively. Inferior oblique underaction had been considered more frequently congenital than acquired. However, 63.0% of our cases were proved to be acquired. The congenital cases were Brown's syndrome and cases of unknown causes and the acquired cases were mainly of myasthenic or traumatic origin. The results of the NCT examination were as follows: incyclodeviation or no cyclodeviation was encountered in all cases of congenital underaction except for one postoperative case, but excyclodeviation rather than incyclodeviation occurred in cases of acquired underaction, which showed ocular torticollis to the side of the paretic eye. This result suggested that some other muscles were involved in acquired cases of seemingly isolated inferior oblique underaction, especially in myasthenia gravis. A diagnosis of myasthenia gravis should be considered first when an acquired inferior oblique underaction occurs with association of excyclodeviation demonstrated by the NCT as well as Cogan's lid twitch sign.

Adolescent↗

PubMed1993

Observation of 100 nm periodic fibrils in mouse corneal stroma by cryoultramicrotomy.

We observed mouse corneal stroma after treatment with 20 mM adenosine 5'-triphosphate (ATP), thin-sectioned by cryoultramicrotomy, with a transmission electron microscope. A wide array of 100 nm periodic fibrils (100 nm PFs) was observed among D-periodic collagen fibrils. By indirect immuno-cryoultramicrotomy with anti-type VI collagen antibody, immunogold particles were located on 100 nm PFs, indicating that 100 nm PFs were composed of type VI collagen. Cryoultramicrotomy is useful for studying the ultrastructure of the extracellular matrix of the corneal stroma.

Adenosine Triphosphate↗

PubMed1993

[Continuous intracarotid infusion of mannitol in severe head injury].

The clinical significance of continuous intracarotid infusion of a small dose of mannitol (ICI of mannitol) was discussed. Eighteen patients suffering from severe head injury with Glasgow coma scale (GCS) less than 6 were treated by ICI of mannitol for the improvement of raised intracranial pressure (ICP). In all of these 18 cases, conventional venous administration of mannitol could not be carried out, because of the unstable vital signs due to hypovolemic shock such as multiple trauma or disturbance of serum sodium and potassium levels. This method requires that a 20% mannitol solution be directly and continuously administered to the bilateral common carotid artery. The ICP 6 hours after the beginning of ICI of mannitol was significantly lower than the ICP just before the treatment. The total amount of excretion of the sodium and potassium through the urine every hour decreased significantly after this method was used. It was also noticed that this method was very suitable for stabilizing the vital signs in cases which had unstable vital signs such as hypovolemic shock. These findings suggested that ICI of mannitol has an advantage over the conventional venous administration of mannitol in cases which had to have correction of serum electrolyte or which had unstable vital signs.

Adolescent↗

PubMed1992

Assembly of 100 nm periodic fibrils (type VI collagen) in human infant corneal stroma.

An experimental model for the age-related changes in the extracellular matrix of the human cornea was developed. Human infant corneal stroma in which no long-spacing collagen occurred naturally was treated with 20 mM adenosine triphosphate (ATP). The ATP-treated cornea was observed and compared with nontreated control specimens by electron microscopy. Numerous 100 nm periodic fibrils which resembled long-spacing collagen were formed by the treatment. These experimentally formed fibrils appeared to attract and aggregate the collagen fibrils with D-periodicity, which indicated a connection between type VI and type I collagen. By ruthenium red staining, the cross-bands of the 100 nm periodic fibrils were positively stained, indicating that glycosaminoglycans or proteoglycans were involved in the formation of these fibrils.

Adenosine Triphosphate↗

PubMed1992

Two cases of acquired syphilis with acute central chorioretinitis as initial manifestation.

Acquired syphilis has become an overlooked cause of posterior uveitis including chorioretinitis. Two male cases of bilateral acute acquired syphilitic chorioretinitis were observed, one of whom demonstrated an early delay of choroidal circulation during fluorescein angiography, possibly indicating the choroidal or subretinal neovascular proliferation which occurred later. Although both patients had been treated with oral prednisone for approximately one month before their initial visit to our clinic, good visual recovery had not been achieved. Diagnosis was first confirmed by the positive results of serologic Treponema pallidum hemagglutination and Venereal Disease Research Laboratory tests. The patients were successfully treated with orally administered bacampicillin, which resulted in the complete recovery of visual acuity and normal fundus appearance except for slight pigmentary changes of the retina in the macular area.

Acute Disease↗

PubMed1992

S-antigen localization in developing rds mouse retina.

The morphology of the photoreceptor cell and localization of the cytoplasmic soluble protein, S-antigen, in the retina of the developing retinal degeneration slow (rds) mutant mouse (2-505 postnatal days) were studied by improved immunocytochemical and freeze-substitution methods. Anti-S-antigen antibody labeling was observed first in the postnatal 10-day retina under light microscope. Labeling signals increased progressively to a maximum level in 20 days, and then decreased gradually to an undetectable level by 505 postnatal days. By electron microscopic immunocytochemical methods, S-antigen was detected first in the photoreceptor cells at 3 postnatal days, and increased with development. It was located in the entire cytoplasm of the photoreceptor cell including the rudimentary outer segment, but degenerated and disappeared by 505 postnatal days. S-antigen was also present in the membranous vesicles budding off from the photoreceptor membrane to the subretinal space. The rds photoreceptor cell seems to lose other soluble proteins together with these vesicles. From these results and other published data, we speculate that the degeneration of the photoreceptor cells may be the secondary effects of the loss of a large amount of soluble and membrane proteins following the malfunction of membrane. Recent reports show the rds mouse must have a gene defect in the membrane component such as peripherin or the 39 kDa protein.

Animals↗

PubMed1992

[Aniseikonia of central serous chorioretinopathy].

Central serous chorioretinopathy (CRS) is one of the typical diseases that accompany micropsia. However very little is known about micropsia of CRS, because of the difficulty to measure "aniseikonia" in terms of micropsia. Aniseikonia in 65 cases of CRS was measured quantitatively by Awaya's New Aniseikonia Tests (NAT). The tests were performed at two different distances of 40 cm (visual angle: 6 degrees) and 20 cm (12 degrees) and under 4 meridians of the halfmoon on NAT, horizontal, 45 degrees, vertical and 135 degrees, respectively. The mean value of aniseikonia under each testing condition was as follows: 6 degrees horizontal -3.13%, 45 degrees -2.56%, vertical -2.13%, 135 degrees -2.57%, 12 degrees; horizontal -1.38%, 45 degrees -1.69%, vertical -1.84%, 135 degrees -1.50%. At 6 degrees aniseikonia is larger in the horizontal meridian than in the vertical with statistical significance (t-test, p less than 0.05), while at 12 degrees aniseikonia is smaller than at 6 degrees and shows no particular tendency in terms of meridian. The phenomenon observed at 6 degrees may be what is called "oriented metamorphopsia".

Adult↗

PubMed1991

In vitro retinal and erythrocyte polyol pathway regulation by hormones and an aldose reductase inhibitor.

The effects of a high-glucose medium, insulin, and an aldose reductase inhibitor (ONO-2235) on sorbitol accumulation were compared in the human erythrocyte and the rabbit retina, while the effects of epinephrine on in vitro sorbitol accumulation were investigated in the human and rabbit retina. In both erythrocytes and the retina, linear increments of sorbitol accumulation were observed in a dose-dependent manner with 5 to 50 mM glucose. These increments were markedly inhibited by 100 microM ONO-2235 but not by insulin (400 microU/ml). In the presence of 5 mM glucose, a dose-dependent increase of the sorbitol content of the rabbit retina was seen following epinephrine stimulation (0.4-4.0 microM and this was markedly reduced by 100 microM ONO-2235. Moreover, both 50 mM glucose and 4.0 microM epinephrine increased the sorbitol content of the retina from a diabetic patient, and the glucose-induced increment in sorbitol was significantly reduced by 100 microM ONO-2235. Our data suggested that aldose reductase inhibitors might be useful for the treatment of diabetic retinopathy, since the polyol pathway appears to be an important factor in its pathogenesis, and that catecholamines might have some role in the activation of the retinal polyol pathway.

Aged↗

PubMed1991

Histological examination of chick embryos with bilateral microphthalmus with reference to laterality in the visual apparatuses.

The histological abnormalities of chick embryos with bilateral microphthalmus were examined in serial paraffin sections with special reference to laterality in the visual apparatuses, including the cornea, lens, neural retina and pigment epithelium. There was marked laterality in the above structures; some eyeballs had individual, if incomplete, sublayers of the cornea and the neural retina, and others not. The sublayers of the neural retina were occasionally observed even in eyeballs at the stage of optic vesicle formation, in contrast to the previous notion that the pigment epithelium induces the maturation of the primordial neural retina after optic vesicle differentiation into the optic cup. There was also a case where developmental differences between the right and left eyeballs were absent except in the lens. These findings suggest that chick embryos with bilateral microphthalmus exhibit a more complex histological profile or diversity than previously considered, possibly as a result of the differential actions of various mutagens and endogenous trophic factors on the developing visual system.

Animals↗

PubMed1991

Age-related changes of microfibrils in the cornea and trabecular meshwork of the human eye.

Microfibrils in the connective tissue can be subdivided into two classes, elastin-associated and elastin-independent microfibrils. The distribution of microfibrils of both classes were studied in the anterior segment of the human ocular tissues, with a view to examine age-related morphological changes. In the trabecular meshwork of infants, the tubular structure of microfibrils was identified and the fibrils were associated with elastin, forming a typical elastic fiber. This was confirmed by the tannic acid-uranyl acetate staining which reacts specifically with elastin. In the cornea, microfibrils were detected in the deep stroma of the infant. They were not associated with elastin (elastin-independent microfibrils). In the glaucomatous eye of a 7-year-old boy, microfibrils were indistinct in the trabecular meshwork. In the corneal stroma of the same eye, microfibrils were observed, but the occurrence was rarer than in the nonglaucomatous infants examined in this study. In the trabecular meshwork of aged persons, no tubular or fibrillar structure was seen around the elastin. Microfibrils were not observed in the cornea. The morphological features and occurrence of microfibrils change with age in the anterior segment of the human eye. Thus microfibrils can be a good indicator for the age-related changes in these tissues.

Actin Cytoskeleton↗

PubMed1991

[The investigation of the stereoacuity in infants measured by the TV-Random Dot Stereo Test].

Evaluation of the level of stereoacuity in infants as early as possible is very important to detecting abnormalities and preventing further disturbance in visual functions. We developed a new instrument which permits the quantitative measurement of stereoacuity in infants. A total of 217 ophthalmologically normal infants were tested and stereoacuity was detected in 141 infants. Stereopsis is likely to arise at 3-4 months of age and develops as the infant grows. It can develop rapidly after the age of one year. The rate of detection was 48% in infants below 6 months old, and 65% as an overall mean among all age groups under 3 years of age. This new instrument, the TV-Random Dot Stereo Test, is very important to quantitatively measure stereoacuity of infants aged under 3 years, more simply and with greater reliability than other kinds of stereo tests for infants.

Age Factors↗

PubMed1991

Detection of platelet mitochondrial DNA deletions in Kearns-Sayre syndrome.

To establish a noninvasive genetic diagnosing method for Kearns-Sayre syndrome, the authors used the polymerase chain reaction (PCR) technique for detecting mitochondrial DNA (mtDNA) deletions in the platelets and directly sequenced the crossover regions of the deleted mtDNA using the fluorescence-based automated sequencing system. The mtDNA deletions were identified in the platelets of three of four patients. The sizes and locations of deletions were determined by the nesting primer PCR method, in which the primary PCR products derived from deleted mtDNAs undergo reamplification using a series of nesting primers. With the fluorescence-based sequencing of templates amplified by the asymmetric PCR method, deleted mtDNA was sequenced directly without cloning. In patient 1, guanine (G) was found at the boundaries of a deleted segment spanning 8400 base pairs (bp) between the CO1 and ND6 genes. In patient 2, a 9-bp directly repeated sequence of 5'-ACCTCCCTC-3' (where A = adenine, C = cytosine, and T = thymine) was found at the boundaries of a deleted segment spanning 7221 bp between the CO1 and ND5 genes. In patient 3, an 8-bp sequence of 5'-TCGCTGTC-3' was found at the boundaries of a deleted segment spanning 4664 bp between the ATPase6 and ND5 genes. Deletions were not detected in the mtDNA of patient 4 or in that of the mothers of the patients. Previously, the genetic diagnosis of this syndrome required muscle biopsy specimens and the use of Southern blot analysis. However, this method requires neither muscle biopsy nor isotopes and is more rapid than the Southern blot method.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

[Insertion anomalies of the horizontal muscles and dysfunctions of the oblique muscles in the A-V patterns].

Insertion anomalies of the horizontal rectus muscles and dysfunctions of the oblique muscles were studied in 141 cases with A-V patterns of 824 patients with horizontal strabisums. The frequency of insertion anomaly among all cases of A-V pattern studied was 49.6%, there were more V pattern insertion anomalies than in those of A pattern, but the ratio of insertion anomalies in each type of A-V pattern was more in the A pattern than in the V pattern. In the oblique muscles, overaction of the inferior oblique muscle in the V pattern and of the superior oblique muscle in the A pattern were frequently encountered and insufficient action of the oblique muscles occurred more frequently in cases A-V esotropia than in cases of exotropia. In cases of combination of insertion anomaly of the horizontal rectus muscles with dysfunction of the oblique muscles, insertion anomaly was involved in 91.3% of cases of overaction of the superior oblique muscles, but only in 37.4% of cases of overaction of the inferior oblique muscles. The combination of insertion anomalies with dysfunction of the oblique muscles suggests a possible existence of simulated dysfunction of the oblique muscles in some cases of dysfunction of the oblique muscles diagnosed preoperatively. At the choice of a procedure in surgical correction, a confirmation of insertions of the horizontal muscles during operations is needed, and for this purpose the perilimbal incision is more appropriate than the fornix incision.

Eye Movements↗

PubMed1991

[Detection of deletions in platelet mitochondrial DNA in Kearns-Sayre syndrome using polymerase chain reaction].

Kearns-Sayre syndrome has been genetically diagnosed by detecting deleted mitochondrial DNA in muscle biopsy specimen using the Southern blot method. However, deleted mitochondrial DNA cannot be detected in the blood by this method. With the limited availability of muscle biopsy specimens in mind, we attempted to establish a noninvasive genetic diagnostic method for this syndrome. The polymerase chain reaction (PCR) was employed for detecting mitochondrial DNA deletions in platelets at levels below the sensitivity of Southern blotting. We selected several pairs of oligonucleotide primers, considering the regions of predilection for deletion in this syndrome, and identified mitochondrial DNA deletions in platelets in three of four patients. The size and the locations of the deletions were determined by the nesting primer PCR method, in which the primary PCR products derived from deleted mitochondrial DNAs were subjected for reamplification using a series of nesting primers. By this method, it was possible to determine whether the products retained a complementary site for each primer. Patient 1 had an 8.3-kb deletion starting within the CO1 gene and ending within the Cyt b gene. Patient 2 had a 7.2-kb deletion starting within the CO1 gene and ending within the ND5 gene. Patient 3 had a 4.7-kb deletion starting within the ATPase6 or the CO3 gene and ending within the ND5 gene. Deletions were detected neither in Patient 4 nor in three mothers of four patients. These results indicate that the present method is useful for noninvasive genetic diagnosis of Kearns-Sayre syndrome.

Adolescent↗

PubMed1990

Oscillatory potentials of local macular ERG in diabetic retinopathy.

The oscillatory potentials (OPs) in electroretinogram (ERG) have clinical values in measuring retinal functions of the early stage of diabetic retinopathy. However, OPs have, until now, been evaluated as components of total ERG recorded with a full field stimulus over the entire retina. Therefore, little information could be obtained about the macular condition (diabetic retinopathy). Using focal stimuli, we successfully recorded OPs in the human macular region. We modified our previously reported system for recording local macular ERG under the fundus monitor with an infrared television fundus camera. We evaluated macular OPs with simultaneously recorded a- and b-waves in many patients with diabetic retinopathy. In some kinds of early diabetic maculopathy, the macular OPs were selectively reduced, leaving the a- and b-waves intact. The macular OPs can be a valuable indicator in assessing the macular function in diabetic maculopathy.

Adult↗

PubMed1990

Implication of polymodal receptor activities in intraocular pressure elevation by neurogenic inflammation.

We studied, using anesthetized albino rabbits, whether polymodal receptors are responsible for rise in the intraocular pressure (IOP) caused by algesic substances, and also whether substance P (SP) is involved in this phenomenon. Intracameral administration of bradykinin (BK), SP, hypertonic saline, and hypertonic glucose caused an IOP rise. The IOP responses to BK and hypertonic saline were reduced by benoxinate, but aspirin reduced only the response to BK. Repeated applications of BK caused a decrease in subsequent responses (tachyphylaxis). These results are consistent with the characteristics of responses of polymodal receptors, and suggest that these IOP responses are produced by neurogenic inflammation. The IOP response to SP also showed tachyphylaxis, but after the tachyphylaxis to SP had been established, subsequent intracameral administration of BK still produced a marked rise in IOP. Moreover, the administration of SP into the posterior chamber, which is known to be the site of the blood-aqueous barrier, caused a much smaller rise in the IOP. These observations indicate that the IOP response to algesic substances might be caused by activation of the polymodal receptors, and that SP might not be a mediator in these responses.

Animals↗

PubMed1990

[Modification of an automated perimeter for dark- and light-adapted perimetry].

A modified automated projection static perimeter which can measure thresholds with lights of three different wavelengths in light-adapted as well as in dark adapted state is described. With the modifications described, this instrument can evaluate relative states of rod and cone mechanisms respectively within the visual field range of 72 degrees. These modifications also enable dark-adapted two-color static perimetry quantitatively across the visual field including profile measurement. Results obtained from normal subjects with these techniques permit assessment of the sensitivity in dark and light and also determination of photoreceptor mediation in the dark. These techniques can evaluate rod and cone dysfunctions separately unlike other retinal function tests, and may show that different mechanisms even in one clinical entity of retinal dystrophies, as well as retinal degenerations, can be demonstrated.

Adaptation, Ocular↗