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Biomedical subjects

Y C Zhou

Publications and source records attributed to Y C Zhou.

9 recordsLinked to original sources
PubMed1992

Preservation.

1. There were no significant differences in 1-year graft survival rates comparing kidneys stored with 3 commonly used cold storage solutions (Collins', EuroCollins, and University of Wisconsin) over the past 12 years, even though preferences have changed sharply. 2. No significant differences in 1-year graft survival rates were noted when comparing kidneys preserved by pump perfusion and those maintained by simple cold storage. The lower incidence of delayed graft function for pump-preserved kidneys was at least partly attributable to a center effect. 3. Prolonged cold ischemia time (CIT) was associated with an increase in delayed onset of function. Of 2,718 kidneys transplanted within 24 hours, 21% did not function well within the first week. The fraction increased to 28% and 33% of kidneys transplanted between 25 and 36 hours (n = 1,858) and after 36 hours (n = 955), respectively (p < 0.01). One-year graft survival rates were 82%, 78%, and 76% for kidneys transplanted within 24 hours, between 25 and 36 hours, and after 36 hours, respectively (p < 0.01, each comparison). 4. HLA matching neutralized the impact of prolonged CIT completely. One-year graft survival was more than 86% in 715 recipients of 0 HLA-mismatched kidneys, regardless of CIT. For recipients of mismatched transplants, survival decreased by 5-6% as CIT increased from less than 24 to more than 36 hours (p < 0.01). Of the mis-matched kidneys with less than 24 hours CIT, up to 83% survived at 1 year compared with 87% of matched kidneys with more than 36 hours CIT (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Effect of verapamil on acute coxsackievirus B3 murine myocarditis.

The effect of verapamil (Ver) on CVB3 murine myocarditis was investigated. It was found that Ver could aggravate the myocardial inflammation, increase the viral replication in myocardium, and raise mortality in mice with viral myocarditis when the drug was injected within the first 6 days after the CVB3 inoculation.

Acute Disease↗
PubMed1991

Phenolic compounds and an analog as superoxide anion scavengers and antioxidants.

Five phenolic compounds and pyridoxine were studied for their activities as both scavengers of superoxide anions and inhibitors of lipid peroxidation. The superoxide anions were generated in a phenazin methosulfate-NADH system and were assayed by the reduction of nitroblue tetrazolium. The superoxide anion scavenging activities of verbascoside and alizarin yellow R were the strongest, followed by those of caffeic acid and phloridzin; vanillin and pyridoxine exhibited the weakest activity. The concentration values yielding 50% inhibition of lipid peroxidation in mouse liver microsomes were 10(-5) M for verbascoside, 10(-4) M for alizarin yellow R and caffeic acid, and 10(-3) M for phloridzin; vanillin and pyridoxine had almost no antioxidative activity. The inhibition of lipid peroxidation by these individual compounds was much weaker than by butylated hydroxyanisole. The results showed that phenolic compounds and pyridoxine have more than one mechanism of action for free radicals and are able to suppress free radical processes at two stages: the formation of superoxide anions and the production of lipid peroxides.

Animals↗
PubMed1991

Sensitization in renal transplantation.

1. The 1-year graft survival rate for 2,615 broadly sensitized patients of first cadaver-donor transplants between 1985 and 1990 was 72%, 7% lower than 15,615 nonsensitized patients and 6% lower than 4,824 moderately sensitized patients. For retransplants, 1,752 broadly sensitized patients had 61% 1-year graft survival rates, 12% lower than 1,299 nonsensitized patients and 8% lower than 1,104 moderately sensitized patients. 2. Rejection of a previous transplant, pretransplant blood transfusions, sex, and a history of pregnancies were the dominant causes of sensitization. 3. The percentage of nontransfused recipients of first cadaver transplants has increased yearly from 10% in 1985 to more than 40% in 1990 in both the UCLA and UNOS Registries. Over the same period, the percentage of broadly sensitized recipients has declined from 15% to 8%. 4. The beneficial effect of pretransplant transfusions (a 4% improvement at 1 year) was limited in first transplants to males and nonsensitized females. No difference in survival rates of sensitized patients comparing transfused and nontransfused was observed. Patients retransplanted without ever being transfused had very poor outcomes. 5. Delayed graft function (DGF) occurred in approximately 20% of nonsensitized, 28% of moderately (1-50% peak PRA), and 37% of broadly sensitized first transplant recipients. Among retransplanted patients, 28% of nonsensitized, 37% of moderately, and 48% of broadly sensitized patients had DGF. 6. HLA-A,B, and DR matching overcame the deleterious effect of sensitization on graft survival. Sensitization had no effect on the outcome of transplants from HLA-identical siblings, but survival decreased by 7-10% in sensitized recipients of mismatched transplants from relatives. Sensitized first cadaver transplant recipients matched for HLA-A,B, or HLA-DR antigens had 1-year survival rates comparable to those of mismatched nonsensitized recipients. 7. First transplant recipients who were nonsensitized using their current serum but had been broadly sensitized in an historical sample had 73% 1-year graft survival, the same as that of patients who were broadly sensitized in their current serum and 6% less than patients who were never sensitized (p less than 0.001). 8. Assuming a random distribution of sensitized patients at UNOS transplant centers using different methods to measure preformed antibody, the antihuman globulin (AHG) method was more sensitive than the NIH or 1-Wash tests. With AHG, 31% of first and 58% of retransplanted patients were broadly sensitized, whereas with the NIH and 1-Wash methods, the corresponding figures were 18-21% and 41-44%.(ABSTRACT TRUNCATED AT 400 WORDS)

Blood Transfusion↗
PubMed1990

Effect of race on kidney transplants.

1. The 1-year graft survival rate for 3,525 Black recipients of first cadaver-donor transplants between 1985 and 1989 was 71%. For 13,866 Whites it was significantly higher at 78%, and 796 Asians had the highest 1-year graft survival rate at 83%. 2. When transplant centers were grouped according to the number of Black patients transplanted between 1985 and 1989, 1-year graft survival rates for Blacks ranged from 67% at centers that transplanted more than 100 Blacks to 74% at centers with 50-100 Blacks to 69% at centers with 1-50 Black transplants. The corresponding survival rates for Whites were 74%, 78%, and 78%, respectively (p less than 0.01 at each center group). 3. When the results were further stratified according to donor race and age, HLA-DR mismatches, and transfusions, a significant 6% difference remained between graft survival rates of Black and White recipients (p less than 0.01). 4. Similar stratified analyses for donor race yielded a significant 8% lower survival rate for Black donor kidneys compared to White donor kidneys (p less than 0.01). 5. More than 25% of Black recipients and donor kidneys were transplanted at 6 of the 204 centers reporting to the UCLA Transplant Registry, whereas 92 centers had transplanted no Black patients. 6. The main difference in survival between Whites and Blacks was among younger patients. There was a 13% difference for those younger than 30 (p less than 0.01), and only a 4% difference among patients older than 45 (p less than 0.05). 7. When HLA-DR antigens were matched, there was no difference in the survival rate between White and Black patients. This result was unaffected by the race of the donor, implying that racial HLA-DR variants may not be a major consideration in matching. 8. Black patients had poor long-term graft survival. The kidney half-life calculated after the first year for Black recipients was 3.7 years, and was 8.7 years for Whites (p less than 0.01). 9. There was a clear "center effect" component to racial differences in first cadaver kidney transplant outcomes related to the size of the Black recipient population. These center effects did not account for the overall difference between Black and White survival rates.

Age Factors↗
PubMed1989

Effect of sex on kidney transplants.

1. Recipient sex had no effect on first cadaver kidney transplant survival. In cadaver regrafts performed prior to 1984, male recipients consistently had lower 1-year graft survival than female recipients. Since 1984 there has been no difference associated with recipient sex. 2. Female donor kidneys had poorer graft survival rates than male donor kidneys. This difference became significant in first cadaver transplants since 1983 and was more evident in retransplants. The difference in regraft survival rates associated with the donor's sex has been dramatically reduced in more recent transplants if the projected results from 1989 transplants are correct. 3. Use of cyclosporine (CsA), pretransplant transfusions, and HLA-A,B mismatches independently contributed to the poorer survival rates of female donor kidneys. A large component of the donor sex effect may have been related to CsA toxicity. 4. Broadly sensitized (greater than 50% PRA) recipients of first transplants had 8% lower 1-year graft survival rates when they received a female donor kidney. 5. Female donors between the ages of 36 and 45 years yielded significantly lower 1-year graft survival rates in recipients of both first transplants and regrafts. This may represent a special donor risk group.

Adolescent↗
PubMed1989

Effect of age on kidney transplants.

1. Graft survival rates ranged from 72-78% at 1 year for recipients over the age of 6 years. Only the very young pediatric recipients had a low 64% 1-year graft survival rate. 2. Older recipients (over 55 years) had a significantly lower 1-year patient survival rate. When we considered death with a functioning graft as a transplant success, older patients actually had the highest graft survival rate. 3. Donor age had an overriding effect on graft survival. The 1-year graft survival rates were 78% for recipients of kidneys from adult donors, 59% from younger pediatric donors, and 67% from older donors. 4. One-year graft survival rates were uniformly over 80% in transplants with no HLA-B,DR antigens mismatched, regardless of recipient or donor age (except when the donor was over 55). The 1-year survival rate for younger pediatric donor kidneys was 62% or less when there were HLA-B,DR mismatches. 5. Pretransplant transfusions improved graft survival by 2-4% in recipients of adult donor kidneys. In recipients of younger pediatric kidneys, graft survival improved by 20% at 1 year with 1-2 transfusions. The enhancing effect of transfusions and matching in recipients of smaller pediatric kidneys is consistent with the idea that these kidneys are more vulnerable to rejection than those from adult donors. 6. Pediatric donors (younger than 15 years of age) accounted for approximately 15% of all donors, whereas pediatric recipients only constituted 2.8% of all recipients in the period of 1984 to 1988. Most kidneys derived from pediatric donors have to be given to adult or older recipients.

Adolescent↗
PubMedDate not supplied

Ras modulates commitment and maturation of 10T1/2 fibroblasts to adipocytes.

The positive association of the ras oncogene with human cancer and the recognition that malignancy may, in part, represent the imbalance between cell proliferation and differentiation have generated intense interest in the potential role of ras in cell differentiation. We investigated this possibility utilizing as a model system the differentiation of the mesenchymal cell line C3H 10T1/2 (10T1/2) to adipocytes, and a series of transfectants of 10T1/2 cells in which the level of the ras gene product (p21ras; Ras) can be effectively up- or down-modulated. In agreement with previous reports, we found that 10T1/2 cultures, propagated in the resting state for several weeks, spontaneously convert to fat cells at a very low frequency. Downmodulation of endogenous p21ras levels, as a consequence of expression of antisense ras, markedly increased the rapidity and frequency of adipose conversion (6- to 10-fold), which was equivalent in magnitude to that effected by the potent differentiating agent 5-azacytidine. Conversely, overexpression of ras completely inhibited cell differentiation. In addition, adipocytes derived from antisense-ras expressing lines were characterized by a decrease in hormone responsiveness, as well as an apparent deficiency in attaining the terminally differentiated state. These findings suggest that Ras may be a negative regulator of the decision-making step of fibroblast differentiation to adipocytes. In addition, Ras may play an essential positive role in the transduction of hormonal signals necessary for full adipocyte maturation during later progression along the differentiation pathway.

Adipose Tissue↗