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Biomedical subjects

T Yasuma

Publications and source records attributed to T Yasuma.

At least 37 records · Page 2Linked to original sources
PubMed1987

Effect of monocular light exclusion on the Stiles-Crawford function.

Contrary to previously published studies, monocular light exclusion did not alter the shape of the Stiles-Crawford function in a substantial manner in four subjects who were patched in this laboratory for one full week. In order to rule out methodological differences, an experimenter from each of the two sets of experiments (current and prior) patched one eye for 1 week, then tested each other. For one subject, there was little effect of patching. For the other, patching had a measurable effect, but it was different from that originally reported. However, the much larger, symmetrical broadening of the Stiles-Crawford function reported in earlier studies was not replicated. A testable working hypothesis to explain the earlier results is discussed.

Female↗
PubMed1987

A pedigree with protanopia and bulbospinal muscular atrophy.

We have studied one family of a pedigree in which bulbospinal muscular atrophy and protanopia were segregated. Genotypes for these disorders were obtained on three generations, and the maximum likelihood estimate of recombination fraction was 0.4 with the lod score method. The results indicated that the two loci are not close; the locus for bulbospinal muscular atrophy is not located near the end of the long arm of the X chromosome.

Color Perception↗
PubMed1986

Histological development of intervertebral disc herniation.

Sagittal and horizontal sections of 257 intervertebral discs obtained at autopsy and material obtained from 441 operations for herniation of a disc were examined histologically. In the material that was taken at autopsy, myxomatous degeneration of the annulus fibrosus increased in proportion to the age of the subject. The bundles in the internal layer of the annulus fibrosus reversed their usual direction and showed myxomatous degeneration, sometimes resulting in posterior and anterior convex bulging in the internal layer of the anterior and posterior parts of the annulus fibrosus, respectively. When material from a disc was surgically removed as a single free fragment (as in a complete extrusion or a sequestration type of herniation), annulus fibrosus with myxomatous degeneration was found in most material, while the nucleus pulposus rarely was. These results suggest that, from the standpoint of pathomechanism, a protrusion type of herniation of the annulus fibrosus exists in which only the annulus fibrosus is protruded due to reversal of the bundles of the annulus fibrosus, without involvement of the nucleus pulposus. This type of herniation would be a separate entity from the protrusion type of herniation of the nucleus pulposus that occurs when the nucleus pulposus is protruded through a fissure in the annulus fibrosus.

Adult↗
PubMed1986

Clinical application of time-dependent perimetry: 1. Results in normal subjects.

A perimeter was constructed, using red light-emitting diodes by remodeling a Foerster's perimeter, to test three time-dependent visual functions, ie, double flash resolution (DFR), which is the time threshold of double flash separation, critical flicker fusion frequency (CFF), which is the threshold of flicker separation and perceptual delay (PD), which is the difference in perception between two locations of the visual field. In 10 normal subjects, the DFR and CFF were determined in the center of the field and in 12 points in the paracentral field 10 degrees away from the center. The CFF value was lower in the center than in the paracentral field where no significant difference was found among various meridians. The DFR values showed a marked individual variation. The value was significantly higher in the upper and lower paracentral fields than in the nasal and temporal fields: the DFR in the center of the field showed no significant difference from the DFR in the nasal and temporal paracentral field. The PD was determined between the center and paracentral fields. Individual variation was small and no significant difference was found among the paracentral fields. These results in normal subjects offer a reference for clinical application of the present test methods for various diseases.

Flicker Fusion↗
PubMed1984

Abnormalities of cone photopigments in genetic carriers of protanomaly.

Anomaloscopic color matching was performed in 57 protanomalous boys. The relative luminous efficiencies of their mothers were measured by flicker photometry to clarify the characteristics of protanomaly carriers. The sensitivity loss of protanomaly carriers in the long wave-length region had a highly significant correlation with the anomalous quotients ( AQs ) of their protanomalous sons. This correlation means that both the luminous efficiencies of the protanomaly carriers and the AQs of their sons are determined by the same "anomalous" cone pigments.

Adolescent↗