Search PubMed⌕ Search

Biomedical subjects

S Shioiri

Publications and source records attributed to S Shioiri.

36 records · Page 2Linked to original sources
PubMed1992

Achromatic form perception is based on luminance, not brightness.

Two figures were examined, one a subjective disk and the other a cup whose shape was revealed by shadows. The figures were presented in a single color on a background of a different color, and the observers adjusted the radiance of one color until, in the first case, the vividness of the subjective contour reached a minimum (minimum subjective contour) or, in the second case, the impression of depth that is due to shadows disappeared (shadow disappearance). The results for these two tasks followed the data for minimum flicker matches (made with the same stimuli) much more closely than those for direct brightness matching. We therefore claim that achromatic form perception in general and subjective contour and shadow perception in particular are based on the intensity dimension measured by flicker photometry, not on that measured by brightness matching. Finally, in agreement with these findings, bleaching of short-wavelength sensitive cones did not affect settings for subjective contours, shadows, or flicker photometry but did affect brightness matching.

Color Perception↗
PubMed1991

Unusual pattern of antibodies to human T-cell leukemia virus type-I in family members of adult T-cell leukemia patients.

Detection methods for the human T-cell leukemia virus type-I (HTLV-I) for blood screening and diagnosis generally rely on antibody tests that use the structural proteins of HTLV-I as antigen. We have found an unusual pattern of antibody reactivity among people who are at high risk of HTLV infection due to being a family member of an adult T-cell leukemia (ATL) patient: a specific antibody reaction exclusively directed to the HTLV regulatory protein tax, and not to the HTLV-I structural proteins. Sera from 7 of 82 (8.5%) structural antibody-undetectable family members of ATL patients had the anti-tax reactivity. Two seroconverters were observed. One seroconverter a healthy resident of Miyazaki, tested negative for structural antibody, but positive for tax antibody. Two years later she tested positive for both. The other seroconverter, an Israeli hemophiliac, tested negative for both antibodies, but converted to tax antibody-positive/structural antibody-negative. The HTLV-I tax-only antibody profile was also observed in sera sets from two other populations at risk for HTLV infection, human immunodeficiency virus-1-infected patients at the Bronx-Lebanon Hospital in New York and Israeli hemophiliacs. DNA samples from lymphocytes of four individuals with antibody reactivity only to HTLV-I tax were tested in polymerase chain reaction experiments; no HTLV-I or -II DNA was detected.

Animals↗
PubMed1991

High incidence of antibodies to HTLV-I tax in blood relatives of adult T cell leukemia patients.

Adult T cell leukemia (ATL) is caused by the human T cell leukemia virus type I (HTLV-I). Although the mechanisms of the leukemogenic process are unknown, the tax gene may have a role in this process. Because clustering occurs with HTLV-I and ATL, members of ATL families were examined for antibodies to the tax protein and compared with matched HTLV-I-positive blood donors. To investigate the antibody response to this protein, a plasmid, pBHX-4, was constructed to express a recombinant tax protein (r-tax). For ATL patients and their HTLV-I antibody-positive blood relatives, the rate of seroreactivity with the r-tax protein was 67.3% (35/52), compared with 51.6% (97/188) for HTLV-I antibody-positive control blood donors (P less than .05). The difference between direct offspring of ATL patients and matched HTLV-I blood donors was even greater (84.2% [16/91] vs. 44.2% [42/95]; P less than .005). Thus, tax antibody positivity in direct offspring of ATL patients may reflect differences in time or route of HTLV-I infection. Alternatively, it might reflect genetic differences in host susceptibility or virus strain.

Adolescent↗
PubMed1991

[A case of EEC (ectrodactyly, ectodermal dysplasia, and cleft lip) syndrome].

EEC syndrome is a rare congenital malformation characterized by ectrodactyly, ectodermal dysplasia, cleft lip and/or palate. We reported a case of EEC syndrome with cleft palate. The patient was a 15-month-old girl. She had split hands of the upper extremities, syndactyly and polydactyly of the right lower extremity, ectodermal dysplasia including sparse hair, enamel hypoplasia and cleft palate. The patient underwent palatoplasty at the age of 18 months.

Abnormalities, Multiple↗
PubMed1990

ISI produces reverse apparent motion.

A moving random-dot stimulus was presented in two sequential frames separated by an interstimulus interval (ISI) during which the field was spatially uniform with luminance equal to either the average luminance of the stimulus field (grey) or that of the black dots (black). In Experiment 1, black ISIs did not affect perception of motion direction but grey ISIs produced motion in the direction opposite to the physical displacement (reverse motion). In Experiment 2, the contrast of the stimulus was reversed simultaneously with the displacement of the random-dot fields so that reverse motion would be seen with no ISI [Anstis & Rogers, Vision Research, 15, 957, 1975]. In this condition, grey ISIs reversed the reverse motion to produce a veridical perception. Finally, in Experiment 3, we examined whether the negative image that follows the stimulus offset was the source of the reversal in motion direction. A gradual offset of the stimulus necessarily reduces the amplitude of the negative response at stimulus offset and also reduced the frequency of seeing reverse motion, suggesting that the apparent reversal of motion direction with ISI can be attributed to the negative phase of a biphasic impulse response function. A simulation of the temporal response to the displacements of random-dot fields demonstrated that the negative phase of a biphasic impulse response function is sufficient to produce the reverse motion. We therefore claim that there is a significant biphasic temporal response function that precedes the analysis of motion in the visual system. This indicates that the overall temporal response function of the visual system is the result of a cascade of functions from early through late stages and that only a portion of the overall temporal response function can be attributed to stages involved in motion analysis.

Contrast Sensitivity↗
PubMed1990

[Seroepidemiological analysis of the age specific prevalence of anti HTLV-I in Miyazaki Prefecture].

Antibody for HTLV-I in sera from 11,224 residents in Miyazaki Prefecture, Japan, was determined by indirect immunofluorescent antibody method to compare age- and sex-specific antibody prevalence among three geographically divided areas of the prefecture. There was a significant difference in the positive rate of older age groups among three areas, 9.0% for the northern part, 14.5% for the southern part and 8.4% for Miyazaki City, in spite of little variation in younger age groups. A marked rise of positive rate in the southern part at the age of 40th was observed, which suggests that changes of some conditions for mother-to-child transmission happened in the time of their birth. Six seroconversions were observed by the follow-up study for five years of the 971 residents. They were between 28 and 38 years of age, four men and two women. This may provide another reason for the increase in antibody positive rate by age in the adult. However, it could not be investigated if the seroconversion was caused by a horizontal transmission from their spouse. The possibility of the long latency of the virus in man as in the experimental animal may also have to be considered.

Adolescent↗
PubMed1990

[Infections in hematological malignancies--clinical analysis of septic patients admitted to the Second Department of Miyazaki Medical College Hospital in the past ten years].

Two hundred and sixty-two patients (actual number 162) of hematological malignancies were admitted to our department from November 1977 to December 1986. Fourty-three of them (16.4%) were demonstrated to be accompanied with sepsis by blood culture. In acute non-lymphocytic leukemias (AML, APL, AMoL) the rate of sepsis was 33.8% (27 patients), while in lymphocytic malignancies (ML, HD, ATL) it was 11.7% (16 patients), particularly being 3.0% in ATL. Among the detected pathogenic microorganisms, gram-negative bacilli were 86.2% in the former and 50.0% in the latter. Especially, Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli occupied 58.6% of the total in the former. Laboratory examination, when sepsis occurred, revealed peripheral neutropenia in acute non-lymphocytic leukemias (mean 831/cmm) but not in lymphocytic malignancy (mean 4,420/cmm). And 20 of the 27 cases showed remarkable neutropenia of below 500/cmm in the former. On the other hand in the latter, out of 16 only one with ATL was the case. Hypogammaglobulinemia was one of the characteristic features in lymphocytic malignancies but not in acute non-lymphocytic leukemias. Hypogammaglobulinemia in lymphocytic malignancies might be affected by long-term immunodepressant therapy. Immunologic skin reaction was demonstrated to be decreased in lymphocytic malignancies on admission. From the findings mentioned above, affecting factors to infections may be mainly neutropenia in acute non-lymphocytic leukemias and immunodeficiency in lymphocytic malignancies. And sepsis can occur frequently under neutropenic condition. In ATL both of humoral- and cellular-immunologic disturbance were detected before therapy. But peripheral neutrophil count was maintained to be normal and this could be the reason for the low septic incidence in ATL despite of total immunodepression.

Agammaglobulinemia↗
PubMed1990

Suppression of delayed-type hypersensitivity to PPD and PHA in elderly HTLV-I carriers.

In a previous study on immune responsiveness among asymptomatic human T-cell leukemia virus type I (HTLV-I) carriers, we found that carriers had significantly reduced delayed-type hypersensitivity (DTH) response to purified protein derivative (PPD) skin testing. The association was strongest among persons at least 60 years of age. In order to evaluate this finding further, we evaluated the response to both PPD and phytohemagglutinin (PHA) in an elderly population. Fifty-six consecutive hospitalized patients with nonimmunosuppressive diseases were examined. None had a history of tuberculosis nor evidence of the known HTLV-I-associated diseases. The subjects' ages ranged from 62-93 years (median = 75 years); 43 were women and 13 were men. Twenty-two of the subjects were HTLV-I antibody positive. Among the carriers, there was an increased level of nonreactivity to PPD, the relative risk adjusted for age (RR) being 1.9 (95% confidence interval, 0.62-5.8), as well as to PHA of RR = 2.3 (0.60-9.0). When subjects were cross-classified for response to both skin tests, 15 of 17 carriers were nonreactive to either or both antigens compared to 15 of 25 noncarriers [RR = 5.1 (0.99-25.9) (p value, one-sided = 0.026)]. The decline in reactivity to both antigens increased with age, but was consistently lower among the carriers. Among subjects with positive reactions to PPD, the degree of reaction as measured by the size of erythema was reduced among the carriers; however, for PHA responders, the response in carriers appeared to be normal. Among the HTLV-I antibody negative subjects, the size of erythema for both antigens was strongly correlated (p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Saccadic suppression of low-level motion.

We measured the detection of motion before, during and after a saccade to explore the effects of a saccade on motion perception. To isolate the low-level motion mechanism, the stimulus was a random-dot field displaced by small distance (0.3 deg) within a stationary frame. The displacement signaled motion clearly if eyes were fixated, but for the displacement during a saccade, motion was not detected whether the displacement was defined in spatial coordinates (expt 1) or in retinal coordinates (expt 2). Since motion could be seen with ISIs longer than the duration of a saccade (expt 3), the suppression cannot be attributed to visual loss during the saccade. Experiment 3 also showed that motion was never seen for a displacement that occurred during a saccade, even though the random dots were replaced by a uniform field during the eye movement thereby eliminating any masking effect of the sweep of the image across the retina. The purpose of the saccadic suppression of motion may be to block out unreliable motion signals that would be produced by a saccade. Since saccade distances are very often greater than the maximum distance over which the low-level motion mechanism can produce accurate direction discrimination for fine textures, motion signals would generally indicate false directions if they were not suppressed.

Eye Movements↗
PubMed1989

Useful resolution for picture perception as a function of eccentricity.

Observers inspected for different lengths of time pictures which contained high-resolution information within an eye-contingent viewing window and low-resolution information outside the area of that window. A recognition test followed in which the pictures inspected were presented together with other, distractor, pictures. The time required to reach 75% picture recognition (the criterion study time) was determined as a function of window size and degree of completeness of video sampling of information outside the window. For each level of information sampling density, criterion study time decreased as window size increased up to a critical size, and then remained approximately constant beyond this size. From these critical-window sizes, a function which describes the resolution actually used by the visual system at each eccentricity (the useful-resolution function) was obtained and this decreased monotonically with eccentricity. The useful resolution at each eccentricity was coarser than the resolution available at that eccentricity as determined by visual acuity, suggesting that useful resolution is not limited by visual acuity. The relationship between useful resolution and saccade length was also analyzed.

Eye Movements↗
PubMed1988

Suppression of tuberculin skin reaction in healthy HTLV-I carriers from Japan.

Although it is thought that infection with human T-lymphotropic virus type I (HTLV-I) is immunosuppressive, this has not been clearly demonstrated among healthy carriers, and there are no data concerning delayed-type hypersensitivity (DTH). To evaluate this hypothesis, DTH to purified protein derivative (PPD) of tuberculin was measured in 126 healthy adults from an endemic area for HTLV-I infection in southern Japan. Among the 39 HTLV-I carriers, only 15% had detectable induration following PPD exposure, compared to 46% of the 87 non-carriers. In addition, the size of erythema among those carriers with a positive reaction was about 70% of that among non-carriers. Overall, there was a significantly inverse association between the degree of DTH response and prevalence of antibody. In relation to subjects with strong to moderate reaction, those with negative or indefinite reaction were 6 times more likely to be a carrier. This association was much stronger among subjects aged 60 years or older than among younger persons. These findings indicate that there is subclinical immunosuppression among HTLV-I carriers, which increases with age.

Adult↗
PubMed1987

Multiple primary cancer risk in patients with squamous cell carcinoma of the oral cavity.

During 6375 patient-years of observation, 136 new cancers developed in 117 of 1429 patients with squamous cell carcinoma of the oral cavity. The risk of multiple cancers was excessive in the upper digestive or respiratory tract in patients with squamous cell carcinoma of the oral cavity, accounting for 87 (64%) of the 136 later cancers. In addition, multiplicity of cancers was site-specific, being common in the oral cavity-esophagus-lung axis and uncommon in sites such as the maxillary sinus and epipharynx. In addition, the observed-to-expected ratio was different in each site of the oral cavity-esophagus-lung axis, i.e., 57.5 for the oral cavity and pharynx, 12.0 for the esophagus, 7.3 for the larynx, and 2.0 for lung cancers.

Carcinoma, Squamous Cell↗
PubMed1985

Functional visual field of patients with visual field loss.

To assess the capability of perceiving forms in patients with visual field loss, a concept of functional visual field was introduced based on determinations of the time required for pattern recognition. Two series of stimulus patterns were made of Japanese syllabic hiragana characters drawn with black dots in the background of open circles of various sizes: the clear stimulus had only open circles in the background and the noisy stimulus had black dots scattered in the background. The stimuli were presented for various durations to 15 normal subjects and 25 patients with narrowed visual field; a correlation of the percentages of correct pattern recognition with the stimulus durations permitted calculations of the 50% recognition time. The recognition time was longer with the noisy than with the clear stimuli. The recognition time with a given stimulus size was longer in patients than in normal subjects. In 3 normal subjects the visual field was artificially narrowed and the recognition time was determined. The recognition time could be expressed by a power function of the ratio of the effective visual field diameter to the diameter of the stimulus pattern. On this basis the functional visual field size of a patient was defined as the size of the artificially narrowed visual field of the normal subject that required the same recognition time as that of the patient. The functional visual field of patients could be correlated with the area of the perimetric field with the V/4 target of Goldmann's projection perimeter. The concept of the functional visual field was found to be useful to express the patients' capability for pattern perception.

Adult↗