Biomedical subjects

R Y Cho

Publications and source records attributed to R Y Cho.

3 recordsLinked to original sources

PubMed2000

Reliability and dimensionality of judgments of visually textured materials.

We extended perceptual studies of the Brodatz set of textured materials. In the experiments, texture perception for different texture sets, viewing distances, or lighting intensities was examined. Subjects compared one pair of textures at a time. The main task was to rapidly rate all of the texture pairs on a number scale for their overall dissimilarities first and then for their dissimilarities according to six specified attributes (e.g., texture contrast). The implied dimensionality of perceptual texture space was usually at least four, rather than three. All six attributes proved to be useful predictors of overall dissimilarity, especially coarseness and regularity. The novel attribute texture lightness, an assessment of mean surface reflectance, was important when viewing conditions were wide-ranging. We were impressed by the general validity of texture judgments across subject, texture set, and comfortable viewing distances or lighting intensities. The attributes are nonorthogonal directions in four-dimensional perceptual space and are probably not narrow linear axes. In a supplementary experiment, we studied a completely different task: identifying textures from a distance. The dimensionality for this more refined task is similar to that for rating judgments, so our findings may have general application.

Adult↗

PubMed1987

Regrafts.

1. One-year patient survival rates improved markedly year by year for regrafted kidney patients reaching 93% in 1986, as compared with 96% in first grafts. 2. The graft survival rate of regrafts also showed steady improvement, but was not benefited by the introduction of CsA as much as in first grafts. One-year graft survival rate was 63% for regrafts in 1986. 3. The functional graft survival was higher with advancing recipient age in first grafts, but remained essentially constant regardless of age in regrafts. We interpret this to mean that older patients have depressed immunologic capability to reject first grafts, but those immunized patients by rejecting a first graft have undiminished reactivity. 4. A high graft survival rate of 68% at one-year was observed for patients who had been sensitized before their first transplant but lost their antibodies before the second transplant. One-year graft survival of those who were not sensitized before both first and second grafts was 60%. 5. The duration of first grafts significantly influences the outcome of second grafts (p less than 0.00001). The highest graft survival was obtained in recipients who had functioning first grafts for more than 2 years (69% at one year), followed by those for recipients whose grafts had functioned for one to 2 years, 6-12 months, and 3-6 months. Patients who lost their first grafts within 3 months had the lowest graft survival rate (44% at one year). 6. The time interval had an influence on the outcome of second grafts.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1986

Regraft kidney transplant survival.

The salient features of one-year regraft transplant survival are as follows: 1. The effect of cyclosporine is less (about 7% increase in one-year graft survival) on regrafted patients than on first grafts. 2. In general we saw a HLA antigen matching effect in cyclosporine- and noncyclosporine-treated retransplant patients. 3. Patients who received living-related HLA two-haplotype matched kidneys did equally as well as a first or regraft recipient. 4. Transfusions seemed to have a minimal effect on regraft survival. 5. It is more important to match in patients who have PRA and the matching benefits translate into 61% and 75% one-year graft survival for zero DR and zero B,DR mismatched regraft patients, respectively. 6. In regrafts, female donor kidneys resulted in 15% lower one-year graft survival than male donor kidneys. 7. Retransplant patients from fair centers showed a significant 13% increase in one-year graft survival with cyclosporine. 8. Cold ischemia time, diabetes, and kidneys used locally or shipped had little effect on the regraft one-year survival. 9. The initial function of the retransplant kidney had a very large effect on the final one-year graft outcome of that kidney and was independent of the use of cyclosporine patients having a functioning kidney at one month had 75% and 72% one-year regraft survival with and without cyclosporine treatment, respectively. Patients having a nonfunctioning kidney at one month had 5% and 8% one-year regraft survival with and without cyclosporine treatment, respectively. 10. Responder and nonresponder classifications as defined by the duration of the first graft resulted in a 10 to 15% difference in regraft survival. 11. The effect of HLA-A,B matching was very strong in responder patients, i.e., there was a 32% difference in one-year regraft survival between zero mismatch and more than two antigens of mismatch. In nonresponder patients, the effect of HLA-A,B matching was only 5%. For HLA-DR locus matching, the difference was 12% for responders and 6% for nonresponders. 12. Cyclosporine use showed about a 10% increase in graft survival in responders and nonresponders. 13. Responder classification was also possible by separating patients who had initial function but no function at one month (responders) from those with function at one month (nonresponders).

Adult↗