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Biomedical subjects

R Mendez

Publications and source records attributed to R Mendez.

At least 73 records · Page 4Linked to original sources
PubMed1993

The significance of a positive flow cytometry crossmatch test in primary kidney transplantation.

This study was conducted to determine the efficacy of the T cell flow cytometry crossmatch (T-FCXM) test in 841 first cadaver donor transplants. Results showed one-year graft survival rates were 82% for T-FCXM-negative patients, compared with 75% for T-FCXM-positive patients (P = 0.01). Early one-month graft failure was 13 percentage points higher in those with a positive T-FCXM than those with a negative T-FCXM. The positive crossmatch patients also had more frequent immunological failures. A positive T-FCXM was found in 39% of the sensitized patients (PRA > 10%) and 8% of those who had not been sensitized. Patients with a positive T-FCXM in either category had a 74% graft survival rate. Thus, most of the T-FCXM-positive results occurred in patients with complement-fixing antibodies. It is suggested that flow cytometry crossmatching (FCXM) be used prospectively, despite the fact that many patients with a positive crossmatch did have successful transplants (TXs). In the current climate of a cadaver kidney scarcity and large recipient waiting pools, utilization of kidneys for patients with the highest probability of success seems a most prudent policy.

Antibodies↗
PubMed1993

Perceptual development and early childhood injuries: a prospective pilot study.

A prospective pilot study of 172 Hispanic children was performed to identify developmental predictors of 9 maternal reports of childhood injuries that required medical attention during the following year. The 1972 McCarthy Scales of Children's Abilities was administered near the children's third birthday and maternal reports of injuries were obtained the following year. Multiple regression analysis indicated that the Verbal, Perceptual, Quantitative, Memory, and Motor Subscales of the McCarthy Scales of Children's Abilities accounted for a small but statistically significant proportion of variance. Within the model, children who showed advanced abilities on the Perceptual Subscale were more likely to reported as having an injury requiring medical attention during the subsequent 12-month period.

Child↗
PubMed1992

Hyperacute and acute kidney graft rejection due to antibodies against B cells.

Because of the perception of its uncertain clinical significance, the B cell crossmatch is not universally performed before renal transplantation. Even though sporadic cases of hyperacute rejection associated with B cell antibodies have been reported, doubts remain in light of other studies suggesting no effect on graft survival. This report describes 4 cases of graft rejection (3 hyperacute and 1 acute) that occurred in patients with anti-B-cell antibodies specific against donor HLA-DR or DQ antigens. Absence of anti-donor class I antibodies was confirmed in all cases by 2-color flow cytometry. Strong evidence for an antibody-mediated mechanism was found in one patient with anti-class I and anti-class II antibodies in serum transplanted with a class II mismatched kidney. In this case, only anti-class II antibodies were recovered in the eluate of the nephrectomy specimen. These four cases were compiled from three different institutions over a four-year period, which confirms the infrequent occurrence of these events. While anti-class II antibodies may not always be detrimental for graft survival, these results also confirm that they have the potential to cause hyperacute or acute graft loss. We conclude that the information provided by the B cell crossmatch should be available at the time that a decision to proceed with a renal transplant is made.

Adult↗
PubMed1992

Flow cytometry PRA, a new test that is highly correlated with graft survival.

IgM antibodies present in the recipient sera are not necessarily harmful to the outcome of the graft. However, one primarily measures IgM with panel-reactive antibody (PRA) determined by microcytotoxicity. In order to develop a potentially more correlative PRA measurement, we have utilized the flow cytometer to measure IgG antibody to a panel of lymphocytes representing HLA antigens. This was accomplished by measuring the median channel shift associated with the patient's serum antibody binding to pooled target cells. The correlation between flow PRA and graft outcome was analyzed in 59 regraft recipients using current serum prior to transplantation. The PRA was determined by both cytotoxicity and flow cytometry. One-year follow up was available on all transplant recipients with 62% 1-yr actuarial graft survival. Cytotoxic PRAs were divided into greater than 10% and less than or equal to 10%, with a 72% vs 70% graft survival at 6 months and 62% vs 62% 1 yr graft survival, respectively. Flow cytometry PRA was divided into greater than 10 and less than or equal to 10 channel shift with 63% vs 86% graft survival at 6 months, and 53 vs 79% 1 yr graft survival respectively (p less than 0.05 for both time intervals). Serum creatinine levels were concomitantly lower at 1 and 3 months in the flow PRA-negative recipients. Flow PRA was a simple, rapid test which eliminates "false" positives due to IgM and detects non-complement fixing IgG, which occurred in 25% of the samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytotoxicity Tests, Immunologic↗