Biomedical subjects

Y W Cho

Publications and source records attributed to Y W Cho.

At least 55 records · Page 3Linked to original sources

PubMed1995

Advances in kidney transplantation: 1985-1995.

Graphs and tables published 10 years ago in our Clinical Kidney Transplants 1985 book are compared to current analyses. Impressive progress is apparent over the past decade. During this period, the effects of factors such as transfusion and the duration of first grafts on second grafts have disappeared, while the effects of factors such as cold ischemia time, regrafts and original disease have diminished in magnitude. Other factors, including HLA matching, donor age and race, continue to exhibit significant influence. It should be emphasized that most of these comparisons apply to one-year graft survival. Thus, our attention must now turn to factors which influence 10-year graft survival. Though 10 years is considered long-term survival to transplant physicians, for patients, it is but a brief period of life.

Adolescent↗

PubMed1994

Plasma t-PA and PAI-1 antigen concentrations in non-insulin dependent diabetic patients: implication for diabetic retinopathy.

Parameters of fibrinolysis, including basal plasma tissue type plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) antigen levels were studied in 49 non-insulin dependent diabetic patients (23 men, 26 women: ages 51.3 +/- 14.9 years) and 16 age matched non-diabetic subjects (9 men, 7 women ages 49.8 +/- 12.2 years) as a control group. Compared to a control group, the diabetic patients had a significantly higher mean plasma t-PA antigen (4.94 +/- 2.68 vs 3.20 +/- 2.30 ng/ml) and PAI-1 antigen (34.86 +/- 16.71 vs. 17.60 +/- 15.36 ng/ml) levels (P < 0.05). Significant univariate correlations were observed between t-PA and body mass index (BMI) (P = 0.0009, r = 0.7217), and PAI-1 were positively correlated with BMI and FBS (fasting blood sugar) in the total diabetic patients (P = 0.0003, r = 0.7217; P = 0.0477, r = 0.2858, respectively). In diabetic patients with proliferative diabetic retinopathy, both PAI-1 and t-PA antigen levels were significantly lower than those of diabetic patients with negative or background retinopathy (P = < 0.05). There were no significant differences of the plasma t-PA and PAI-1 levels between diabetic patients with micro- and macroproteinuria. This study conducted on non-insulin dependent diabetic patients suggests that they have significantly higher t-PA and PAI-1 antigen levels than do control subjects, and these findings appear to correlate negatively with proliferative retinopathy observed among the patients studied.

Analysis of Variance↗

PubMed1994

HLA matching effect: better survival rates and graft quality.

1. HLA matching remains a major factor in kidney transplantation. Much of the total graft failures can be eliminated through better HLA matching. 2. Very early effects of HLA matching can be seen with the requirement of dialysis within one week. 3. Even among kidneys which are functioning at the beginning of each period, more frequent rejection treatment with increasing numbers of A,B,DR mismatches was observed. 4. Among functioning kidneys, HLA matching affects the quality of kidney function, as reflected in the serum creatinine levels during all periods. 5. Immunological graft failures (regardless of cause) are strongly associated with HLA mismatching. 6. The effect of HLA matching was similar at centers with high or low overall graft survival rates. 7. The fraction of zero-A,B,DR mismatches has increased dramatically in recent years. However, this is a large difference in the numbers between centers and OPOs. 8. Preformed cytotoxic antibodies to HLA tend to force a higher degree of matching for the A and B loci, resulting from T-lymphocyte crossmatching. 9. Because of the linkage of the 3 HLA loci (A, B, and DR), matching for one often results in matching for 2 or 3 of the loci. 10. Chronic glomerulonephritis patients having DR1 had superior graft survival rates than patients without DR1. 11. HLA frequencies in IDDM, hypertensive nephropathy, CGN and PC were significantly different from controls in many Class II specificities and some Class I specificities.

Disease Susceptibility↗

PubMed1993

Cadaver-donor renal retransplants.

1. There was a dramatic improvement in survival rates for retransplanted patients between 1989 and 1991. The proportion of cadaveric kidneys used to retransplant patients has decreased from 18.4% in 1984 to 14.3% in 1992. In 1992, the 81% one-year survival rate for second transplants nearly reached that of first transplants. 2. Despite recent improvements in regraft survival, the PGST remained the strongest predictor of second graft outcome. One-year regraft survival rates were 54% when the PGST was one to 3 months and 75% when the PGST was more than one year. The steady improvement in second graft survival rates may be influenced by retransplanting more patients with a longer PGST. 3. Patients with broadly reactive anti-HLA antibodies (PRA > 50%) had 10% lower regraft survival rates than nonsensitized patients (p < 0.001). 4. A repeated HLA-DR antigen mismatch resulted in 6% and 13% lower regraft survival at one and 3 years, respectively, compared with patients who had at least one HLA-DR mismatch, but not for the same antigen mismatched previously (p < 0.05). 5. Recipients expressing HLA-DR1 had an 81% one-year second graft survival rate compared with 75% for patients lacking DR1 (p < 0.001). 6. Matching for HLA-B,DR and HLA-A,B,DR antigen combinations resulted in 80-82% one-year regraft survival rates for second and multiple transplant recipients, compared with 57-74% for completely mismatched transplants. 7. Transplants from donors under age 6 or over age 55 had significantly poorer outcomes than those involving kidneys from donors in the intermediate age range. The results of transplants at the extremes of donor age were very poor when the recipient was retransplanted. 8. Among recipients of second and multiple transplants, prophylactic OKT3 yielded 82% and 72% one-year regraft survival, respectively, compared with 75% and 66% with no antibody induction (p < 0.001 for second transplants). 9. Regraft survival rates comparable with those for primary cadaveric transplants reported to the UNOS Registry since 1991 justify the use of cadaver-donor kidneys for low-risk patients seeking second renal transplants.

Adolescent↗

PubMed1992

Survival of nationally shared, HLA-matched kidney transplants from cadaveric donors. The UNOS Scientific Renal Transplant Registry.

BACKGROUND: The importance of HLA histocompatibility typing to the outcome of transplantation of cadaveric kidneys has been controversial. Four years ago, a prospective trial began in all U.S. transplantation centers to determine whether the results of transplantation would improve with the nationwide shipment of kidneys from cadaveric donors to waiting patients undergoing dialysis when there was a match at the HLA-A, B, and DR loci. METHODS: A total of 1386 cadaveric kidneys were shipped from 108 organ centers to 198 transplantation centers and distributed among HLA-matched recipients, 1004 of whom were receiving a first transplant and 382 of whom were receiving a subsequent transplant. Graft survival in these recipients was compared with that in 22,188 recipients of first transplants and 3950 recipients of subsequent transplants whose HLA antigens differed from those of the donor. RESULTS: The rate of graft survival at one year in recipients of HLA-matched first transplants was 88 percent, as compared with 79 percent in the recipients of mismatched grafts (P less than 0.001). The estimated half-life of the kidney after the first year was 17.3 years for matched grafts, as compared with 7.8 years for mismatched grafts (P = 0.003). Among paired kidneys from 470 donors, one-year graft survival was 87 percent in the recipients of matched first grafts, as compared with 80 percent in the recipients of the contralateral kidneys, who did not have HLA matches with the donors. In donors and recipients matched for the more highly defined split Class I and Class II HLA antigens, the rate of graft survival after one year was as high as 90 percent. CONCLUSIONS: The collaborative renal-transplantation program for HLA matching of donors and recipients yielded an increased rate of one-year graft survival and an estimated half-life for matched grafts twice that for mismatched grafts. An increased role for HLA matching in kidney allocation is therefore indicated.

Adolescent↗

PubMed1992

Immunogenetic and nutritional profile in insulin-using youth-onset diabetics in Korea.

There are few reports on the genetic, immunological and nutritional characteristics of insulin-using youth-onset diabetes mellitus, insulin-dependent diabetes mellitus (IDDM) and malnutrition-related diabetes mellitus (MRDM) in Korea. Among 1266 hospitalized Korean diabetics, 29 (2.3%) were IDDM and 84 (6.6%) were MRDM. A diabetes history of first-relatives (28.6%) was more frequently found in the MRDM group than in the IDDM (14.8) and non-insulin-dependent diabetes mellitus (NIDDM) (19.0%) groups. HLA-DR4 was more common among IDDM (54.2%) and MRDM (52.4%) patients than controls (26.3%), and HLA-DR3 was more common among only IDDM patients (29.2%) than controls (10.9%). Conventional islet-cell antibodies were detected in 8 of 15 IDDM patients tested (53.3%) and in 11 of 22 MRDM patients (50.0%). MRDM patients had higher serum basal (1.02 +/- 0.51 ng/ml) and peak (1.44 +/- 0.76 ng/ml) C-peptide concentrations than IDDM patients, but lower concentrations than NIDDM patients. Before the onset of diabetes, the calorie intake of 21 MRDM patients assessed was 63.1% of the daily requirement and the intake of carbohydrate, protein and fat was 71.7%, 55.9% and 39.8%, respectively. In summary, our data suggest that IDDM in Korea is associated with HLA-DR3 or HLA-DR4, indicating a risk for IDDM in Western societies; furthermore, MRDM has a history of undernutrition at the preonset period and is also associated with HLA-DR4. It might be also concluded that MRDM in Korea is another expression of IDDM caused by the shortage of some nutrients for the structural and/or functional maintenance of pancreatic beta-cells.

Adolescent↗

PubMed1992

Analyses of the UNOS Scientific Renal Transplant Registry at three years--early events affecting transplant success.

The success of cadaveric renal transplants in the first year is determined largely by events that transpire during the transplant hospitalization. This conclusion is based upon analyses of data on 19,525 cadaver donor renal transplants performed since October 1987 and reported to the UNOS Scientific Renal Transplant Registry from more than 200 centers nationwide. Graft survival rates at 1 year differed by 20-30% depending upon whether or not the transplanted kidney functioned immediately and upon whether the patient required dialysis during the first week posttransplant, experienced rejection, or was discharged with a kidney that was functioning well. Recipients whose discharge serum creatinine level was less than 2.6 mg/dl or whose graft was functioning well at the time of discharge had 88% 1-year graft survival. A multistep logistic regression analysis showed cold ischemia time, transfusions, donor age and cause of death, HLA-DR mismatches, and peak sensitization to be significant factors in the first week. Prophylactic antilymphocyte antibodies (ALG/OKT3) reduced the incidence of rejection from 30% to 20% during the transplant hospitalization, but apparently only delayed rejection. By 6 months there was only a 3% reduction with ALG and a 5% reduction with OKT3 in the incidence of reported rejection and a 2% difference in 1-year graft survival. Although graft and patient survival are important measures of transplant success, graft survival is predicted upon both early and late events. The course of the transplant during the initial hospitalization and the quality of function at discharge were the strongest determinants of 1-year graft survival.

Adolescent↗

PubMed1992

Plasma t-PA and PAl-1 antigen concentrations in non-insulin dependent diabetic patients: effects of treatment modality on fibrinolysis.

Basal plasma tissue type plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAl-1) antigen levels were studied in 49 non-insulin dependent diabetic patients (23 men, 26 women: ages 51.3 +/- 14.9 years) and 16 age matched non-diabetic subjects (9 men, 7 women: ages 49.8 +/- 12.2 years) as a control group. Compared to a control group, the diabetic patients had a significantly higher mean t-PA antigen (5.15 +/- 3.02 vs 3.20 +/- 2.30 ng/ml) and PAl-1 antigen (35.89 +/- 18.59 vs 17.60 +/- 15.36 ng/ml) levels (p < 0.05). Plasma t-PA antigen level was not influenced by each treatment modality. There was a significant decrease of plasma PAl-1 antigen level after Metformin administration compared to that of before Metformin administration (39.74 +/- 19.39 vs 25.14 +/- 16.18 ng/ml) (p < 0.05), and the insulin-treated group showed a tendency for a decrease of plasma PAl-1 antigen levels after insulin administration but this did not reach statistical significance (29.93 +/- 15.37 vs 17.32 +/- 10.60 ng/ml). Sulfonylurea did not change both plasma t-PA and PAl-1 antigen levels. In conclusion, diabetic patients have high t-PA and PAl-1 antigen levels. Biguanide reduced plasma PAl-1 antigen levels, which might play some helpful role in the improvement of chronic complications in NIDDM.

Antigens↗

PubMed1992

Center effect in the UNOS Renal Transplant Registry.

Based upon univariate and multivariate analyses of transplant center effects: 1. Among the 115 centers selected for these analyses, there was no correlation between 6-month graft survival rates and half-lives projected for grafts surviving 6 months. 2. There was no significant center effect for living-related donor transplantations. 3. Centers that had the poorest short- and long-term survival performed more cadaveric transplants with patients in poor health at the time of transplant, more often transplanted a recipient other than the one originally identified for a particular kidney, and more often transplanted kidneys with prolonged cold ischemia, and kidneys from pediatric (age 0-11) donors, older (ages over 50) donors, Black donors, or donors who died with cerebrovascular accidents. 4. After adjusting for 17 potentially confounding variables, the difference between the best and worst center groups was the second most detrimental factor (following broad sensitization) in the first 6 months and was the factor ranked ninth in long-term survival. 5. The transplant year has emerged as a significant factor in long-term survival. This suggests that the late loss rate for transplants performed after 1988 may be diminishing. 6. The health status of the patient at the time of transplant was the dominant factor affecting long-term survival. 7. The choice of outcome variable and the selection criteria used in center classification affect the magnitude of the center effect and its relationship to other significant variables that influence graft outcome.

Adolescent↗

PubMed1991

Euglobulin fibrinolytic activity in NIDDM patients.

The euglobulin fibrinolytic activity was measured in 56 non-insulin-dependent diabetics and 118 age-matched healthy controls before and after venous occlusion for 5 min at 100 mmHg of the left antecubital vein. In the basal state, fibrinolytic activity was impaired in diabetics compared with controls (93.1 +/- 6.7 vs 101.6 +/- 0.9 BAU) (P less than 0.05) and plasma fibrinogen level was increased but this did not reach statistical significance (467.3 +/- 264.1 vs 359.2 +/- 200.2 mg/dl). In diabetics, stimulated fibrinolysis following venous occlusion was depressed compared with controls (110.6 +/- 3.9 vs 121.6 +/- 1.9 BAU) (P less than 0.05). No relation of fibrinolytic activity to age, duration of diabetes, obesity, serum triglyceride, HbA1c, or 24 h proteinuria was demonstrated. In the diabetic retinopathy group, the fibrinolytic activity was lower than in the non-retinopathy group. Diabetics with long-standing diabetes (10 years or more) who remained free from retinopathy had significantly increased fibrinolytic activity than the diabetics with short-standing diabetes (less than 10 years) who have developed retinopathy (P less than 0.05). These findings imply a poor fibrinolytic activity, not in all diabetics, but only in those with retinopathy, and this may play a role in the development of diabetic retinopathy.

Age Factors↗

PubMed1991

Assessment of interaction among risk factors in three-month graft survival of first cadaveric renal transplantations: a case-control study.

1. Most multivariate analyses of first cadaver-donor kidney grafts have assumed additivity of covariate effects, ignoring possible interaction terms. Using 21,895 primary cadaveric renal transplants reported to the UNOS Kidney Registry, we attempted to assess whether or not strong interaction effects on graft survival existed among 11 important factors. Due to the small number of cases for many multiway factor combinations, our interaction analyses were limited to studying how stratification by 1 factor affected the graft failure risks of a second factor. Two stratification factors were chosen: recipient race and age. 2. Although there was little evidence of strong factor interaction across 5 racial groupings, differences in risk for several factors (recipient age, donor race, donor age, HLA-B,DR mismatching, and cold ischemia time) between Blacks and non-Blacks appeared to be nonadditive (2 examples listed in Table 3). 3. In a more restricted population of White recipients older than age 16, there was only evidence of interacting effects on 3-month graft survival between donor sex and recipient age. 4. Despite many pairwise factor associations (Figs. 1, 3), it appears that the majority of the transplant covariates are additive with respect to the risk of early graft loss. In future analyses, we suggest inclusion of appropriate interaction terms relating the above-mentioned factors with recipient race and age.

Adolescent↗

PubMed1990

Long-term graft survival.

1. Long-term graft survival is characterized by failure rates that are essentially constant after about a year or 2. The rate has not varied appreciably among cohorts defined in terms of transplant year. 2. Transplants with an excellent clinical course throughout the first 3 months (about 2-thirds of cadaver-donor first transplants) have substantially better long-term graft survival than those with a less favorable early course. 3. Having an excellent early clinical course did not remove the effects of the several factors related to long-term survival. 4. Use of cyclosporine did not relate to long-term survival. 5. Factors related to short-term graft survival (1 year), generally related to long-term survival and in the same direction. Cyclosporine use was a major exception. 6. The dominant factor for long-term survival was tissue matching as reflected in donor categories: HLA-identical sibling, parent, and cadaver. 7. Black recipients had a decidedly poorer long-term survival than recipients of other races/ethnicities. 8. Transplant center was a dominant factor in long-term graft survival. 9. Multivariable analysis did not materially alter the findings obtained from factors considered separately. This was attributable to the sensitivity associated with small standard errors resulting from the large number of cadaver-donor transplants and the combination of smaller numbers and longer survival of living-related transplants.

Age Factors↗

PubMed1990

The UNOS Scientific Renal Transplant Registry: multistep regression models on kidney graft survival.

1. Two-step Cox regression analyses showed that, for White recipients of first cadaver transplants, pretransplant transfusions, HLA-DR mismatch, donor race, CIT, size mismatch, PRA, old donor, and recipient age were significant prognostic factors during the first 6 months posttransplant, and after that, older donor, CIT, and size mismatch continued to have effects on graft survival in the longer term. 2. For African-American recipients of first cadaver transplants, pediatric donor, cause of donor death, and increasing second warm ischemia time were major risk factors in the early period, but in the late period, the effect of donor age dominated other factors. 3. Multistep linear logistic regression and two-step Cox regression analyses yielded similar results, with donor-related and histocompatibility factors dominating survival outcome in both the short and long terms.

Adult↗

PubMed1989

Fifteen-year kidney graft survival.

1. Among patients transplanted in 93 selected centers with good follow-up data, the 10-year graft survival of first cadaver-donor transplants was 18%, parental donor grafts 39%, and HLA-identical sibling donor grafts 66%. The respective half-lives were 6.8, 10.8, and 24.5 years. The donor relationship has been the most important factor in long-term success. 2. Patient half-life for recipients younger than 16 was 36 years; for recipients 16-50 years old it was 17.6 years, and for those over age 50, it was 10.4 years. This marked difference in patient half-lives severely affected functional graft half-lives for the 3 age groups; 6.8, 10.3, and 16.7 years, respectively. However, the differences in patient survival for the 3 age groups were not significantly reflected in graft half-lives that were 6.8, 7.7, and 6.5 years, respectively. Thus, graft loss resulting from rejection was significantly lower in older than in younger patients. 3. Cadaver-donor kidneys with cold ischemia time up to 12 hours and half-lives of 9.1 years in transplants performed before 1975, compared to half-lives of 6.4 years for those with more than 24 hours cold ischemia time. In transplants performed between 1980 and 1983, the half-life of kidneys with cold ischemia time up to 12 hours was 8.7 years, compared to 6.9 years for those with more than 24 hours cold ischemia time. The long-term effect of cold ischemia persists but has diminished in recent years. 4. HLA-A,B loci matching had a significant effect on long-term graft survival. The 10-year graft survival of A,B matched grafts was 30% compared to 18% for 3 or 4 HLA-A,B mismatched transplants. This difference increased at 15 years to 25% in the matched grafts and 10% in the mismatched grafts. 5. A very strong recipient race effect was evidenced by the 24% 10-year graft survival in Whites compared to 10% in Blacks. The half-lives were 8.2 in Whites and 4.8 in Blacks. 6. A listing of 15-year graft survivors has been compiled according to transplantation centers. There was a total of 969 from cadaver donors, 283 from parental donors, and 457 from sibling donors. 7. An analysis of the characteristics of the 15-year graft survivors showed a preponderance of patients with favorable factors, noted in the analysis above. As might be expected, the most striking was the fact that 27% of the 15-year survivors had received kidneys from sibling donors, despite the fact that such donors comprised only 17% of those transplanted in the pre-1975 era.

Adolescent↗

PubMed1988

Long-term survival.

1. In transplants performed between 1971 and 1986, first cadaver donor grafts had a half-life ranging from 6.6 to 7.5 years in the period after the first year. Second cadaver donor grafts had a half-life of 5.1 to 6.5 years. Parental donor grafts had a half-life of 9.3 to 11.8 years, whereas HLA identical sibling donor transplants had a half-life of 19.1 to 26.5 years. Siblings with no haplotype in common had an average half-life of 8.7 years. 2. Between 1971 and 1984, white recipients had an average half-life of 7.7 years, which increased to 9.3 years in 1985-1986. Black recipients' half-life decreased from 5.4 years in 1975-1976 to 3.5 years in 1985-1986. The reason for this decrease is not apparent. 3. The half-life of transplants of different recipient ages did not vary significantly. The average half-life during this period of study was 7.4 years for those younger than 21 years of age, 8.2 years for recipients 21 to 50 and 6.7 years for those older than 50. 4. In the early data, there was some evidence that the half-life of kidneys with cold ischemia below 13 hours was superior. However, in the latest period (between 1983 and 1986) the average half-life was 7.6 years for CIT below 13 hours, 7.2 years for those with 13 to 24 hours and 6.4 years for more than 24 hours. 5. For patients receiving kidneys with no HLA-A,B mismatches, the average half-life was 10.1 years. Those with A,B mismatches had a half-life of 6.7 years, and for those with no A,B antigens in common, the average half-life was 6 years. 6. In the period after 1981, the average half-life of patients with no A,B,DR mismatches was 9.1 years compared with 6.5 years for those with A,B,DR mismatches and 5.4 years for those with no A,B,DR antigens in common.

Adult↗

PubMed1984

Gas chromatographic analysis of cetiedil, a candidate antisickling agent, in human plasma with nitrogen-sensitive detection.

In this report a sensitive gas chromatographic assay for cetiedil, a candidate antisickling agent, in human plasma is described. After a triple extraction procedure, cetiedil was analyzed without derivatization with a nitrogen-phosphorus detector (with papaverine used as the internal standard.) Cetiedil was measured in plasma samples taken from human volunteers administered the drug intravenously.

Adult↗

PubMed1984

Nitroimidazoles in the treatment of trichomoniasis, giardiasis, and amebiasis.

Nitroimidazoles have been extensively evaluated in the treatment of trichomoniasis, giardiasis, liver and intestinal amebiasis. The most widely used are metronidazole, tinidazole, ornidazole, and secnidazole. Tinidazole, ornidazole, and secnidazole have a much longer half-life than metronidazole, allowing single-dose or once daily administration. Nitro-5-imidazoles remain extremely effective drugs for treating protozoans, Trichomonas vaginalis, Entamoeba histolytica, and Giardia intestinalis. Although all are suspected of potential carcinogenicity, they are the drugs of choice for treating protozoal infections.

Amebiasis↗

PubMed1983

Clinical effects of intravenous cetiedil, a candidate anti-sickling agent.

As part of a Phase I clinical trial, the clinical effects resulting from both single and multiple dose infusions of cetiedil, a candidate anti-sickling agent, were evaluated. Multiple doses of up to 0.45 mg/kg every six hours for four days were safe and well-tolerated in adult male volunteers. Most adverse reactions to cetiedil are related to its anticholinergic properties (dryness of mouth, blurred vision, spacy feelings, disorientation) or vasodilatory effects (light-headedness, vertigo, cold extremities); these side-effects were dose-related with regard to incidence, severity and duration. Moderate to slight reductions in systolic and diastolic blood pressure and pulse rate were statistically significant but no dose-related. There were no significant changes in respiratory rate, ECG, biochemical or haematological parameters. Adverse reactions were transient and required neither medical intervention nor discontinuance of infusions.

Adult↗