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Biomedical subjects

R Ettenger

Publications and source records attributed to R Ettenger.

At least 19 recordsLinked to original sources

Single-dose pharmacokinetics and tolerability of everolimus in stable pediatric renal transplant patients.

Everolimus (Certican; RAD), a novel macrolide with potent immunosuppressive and anti-proliferative activities, prevents acute rejection in adult recipients of renal transplantation. This phase I trial conducted in stable pediatric renal transplant patients examined the single-dose pharmacokinetics, safety, and tolerability of everolimus in combination with cyclosporin A (CsA; Neoral) and corticosteroids, with or without azathioprine. Nineteen pediatric patients were enrolled and received a single 1.2 mg/m2 dose of everolimus. Everolimus was safe and well tolerated, with a low incidence of adverse events reported and none judged to be related to the study medication. Everolimus administration did not increase infection rates or produce clinically significant changes in vital signs or changes in electrocardiograms. Apparent clearance and volume of distribution of everolimus increased with age, weight, and body surface area in a generally linear manner across the pediatric demographic ranges. Compared with adults from a previous study, apparent clearance (L/h) and distribution volume (L) were lower in pediatric patients, whereas the elimination half-life was similar. Single-dose everolimus co-administration did not affect the steady-state pharmacokinetics of CsA. Based on this information, pediatric patients will need a dose scaled down for body size, but can probably maintain the same twice-daily dosing schedule used in adults.

Administration, Oral↗

The use of mycophenolate mofetil suspension in pediatric renal allograft recipients.

Mycophenolate mofetil (MMF) is widely used to prevent acute rejection in adults after renal, cardiac, and liver transplantation. This study investigated the safety, tolerability, and pharmacokinetics of MMF suspension in pediatric renal allograft recipients. One hundred renal allograft recipients were enrolled into three age groups (33 patients, 3 months to <6 years; 34 patients, 6 to <12 years; 33 patients, 12 to 18 years). Patients received MMF 600 mg/m2 b.i.d. concomitantly with cyclosporine and corticosteroids with or without antilymphocyte antibody induction. One year after transplantation, patient and graft survival (including death) were 98% and 93%, respectively. Twenty-five patients (25%) experienced a biopsy-proven (Banff grade borderline or higher) or presumptive acute rejection within the first 6 months post-transplantation. Analysis of pharmacokinetic parameters for mycophenolic acid (MPA) and mycophenolic acid glucuronide showed no clinically significant differences among the age groups. The dosing regimen of MMF 600 mg/m2 b.i.d. achieved the targeted early post-transplantation MPA 12-h area under concentration-time curve (AUC0-12) of 27.2 microg h per ml. Adverse events had similar frequencies among the age groups (with the exception of diarrhea, leukopenia, sepsis, and anemia, which were more frequent in the <6 years age group) and led to withdrawal of MMF in about 10% of patients. Administration of MMF 600 mg/m2 b.i.d. is effective in prevention of acute rejection, provides predictable pharmacokinetics, and is associated with an acceptable safety profile in pediatric renal transplant recipients.

Adolescent↗

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↗

Los Angeles organ sharing: twenty-six-year report.

1. The Los Angeles Transplant Society and the Regional Organ Procurement Agency of Southern California (ROPA) was established in November 1967. ROPA was the first such organization in the United States. 2. The use of simple cold storage and shipment of kidneys by commercial airline resulted from pioneering concepts developed in the Los Angeles area from 1968-1969. 3. In the 26-year period of ROPA's operation, it has coordinated 8,446 kidney transplants. 4. All kidneys transplanted in 1993 were allocated according to the UNOS point system. 5. Allocating all kidneys under the point system has not significantly disadvantaged either large or small transplant centers in the greater Los Angeles area. 6. Racial distribution of recipients: 13% Black (compared with Los Angeles population of 12% and 6% donor population). Blacks represent 20% of the recipient waiting list. Hispanic recipients were 31% (compared to Los Angeles population of 40% and donor population of 30%). Hispanics comprised 28% of the waiting list. 7. The average waiting times for centers in the Los Angeles area ranged from 14-19.4 months. Transplanted patients waited an average of 16.3-22.1 months. 8. "Required request" had a significant effect on the number of referrals but did not produce a meaningful increase in the number of kidneys transplanted.

Cryopreservation↗

Sequential therapy in pediatric cadaveric renal transplantation: a critical analysis.

Cadaveric renal transplant survival rates in children are still somewhat inferior to those reported in adults. Sequential therapy, an immunosuppressive program in which a course of antilymphocyte preparation is used immediately postoperatively and followed in sequence by oral maintenance immunosuppression, has a number of features that might be expected to improve pediatric transplant outcome by addressing some of the metabolic and immunologic difficulties encountered in children. This article examines the rationale for sequential therapy in pediatric renal transplantation. It also examines the use of sequential therapy in children. Sequential therapy appears to significantly improve cadaver renal allograft outcome in children without compromising patient survival. There was a slight improvement in 1- and 2-yr graft outcomes when OKT3 was used prophylactically when compared with antithymocyte globulin, but this difference did not reach statistical significance. Almost 60% of patients receiving OKT3 for sequential therapy remained free of rejection. Major drawbacks of sequential therapy include the adverse side effects of the antilymphocyte preparation, infection, and the possibility of lymphoproliferative syndrome. The implications of these problems as well as potential strategies for ameliorating them are discussed.

Adult↗

Kidney allocation under the UNOS point system: an update.

1. The 1,480 patients awaiting cadaveric renal transplants at 14 Southern California transplant centers as of December 3, 1992, were compared with patients transplanted using a point system for one kidney and a hospital-based allocation for the second, or the current system allocating all locally procured kidneys by the point system with regard to several demographic parameters. 2. Of 1,472 waiting patients with sensitization data, 8.5% were broadly sensitized (> 80% PRA). Of the 737 kidneys allocated by the point system, 7% went to broadly sensitized patients, compared with 3% of 438 kidneys allocated by the hospitals (p < 0.001). 3. Of 1,470 waiting patients with information available, 23% were awaiting a repeat transplant. Under the point system, 18% of kidneys were used for repeat transplants compared with 9% of hospital-allocated kidneys (p < 0.001). 4. Of 1,434 waiting patients where the time waiting was available, 26% had waited 1-2 years, 12% 2-3 years, and 6% more than 3 years. Under the point system, patients waiting longer received significantly more kidneys than those recently added to the list: 35% had waited 1-2 years, 21% 2-3 years and 14% more than 3 years (p < 0.001). Kidneys allocated by the hospitals were transplanted to patients in approximately the same proportions as the waiting list: 29% to those waiting 1-2 years, 10% 2-3 years, and 3% more than 3 years. 5. Racial distribution of recipients was not significantly different under either allocation system from that of the waiting list. Whites comprised 39% of waiting patients, the same as the population of Los Angeles County.(ABSTRACT TRUNCATED AT 250 WORDS)

California↗

Evaluation of the UNOS point system for kidney recipient selection.

1. The ultimate distribution of 479 consecutive cadaver donor kidneys in the Los Angeles area was examined to determine whether the distribution had been equitable. Half of the kidneys had been allocated by the UNOS point system (or slight modifications thereof) and half by the transplant centers according to their own criteria. 2. With respect to waiting time, the pool of 1,000 was composed of 14% patients who had waited more than 2 years. The UNOS point system forced the transplantation of more patients (27%) who had waited longer than 2 years than the nonpoint system (11%). 3. Although the waiting pool was composed of 28% waiting for retransplantation, the UNOS point system resulted in transplantation of 16% and the nonpoint system, 8%. 4. In the waiting pool, 16% of the patients had cytotoxic antibodies reactive to more than 80% of the panel, whereas 11% of the transplants by the UNOS point system were transplanted into highly sensitized patients and only 2% of the patients transplanted by the nonpoint system were highly sensitized. 5. In Los Angeles, where 11% of the population is Black, 10% of the kidneys transplanted were into Black patients. Since 18% of the waiting pool of patients were Black, some shortfall was noted. However, this can be attributed to the fact that only 7% of the donors were Black. The importance of increasing donation from the Black community is emphasized. 6. Because of the limited pool size of 1,000 patients only a small number of 0 B,DR transplants were achieved.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation Studies as Topic↗

Plasma exchange improves the glomerulonephritis of systemic lupus erythematosus in selected pediatric patients.

The effects of short-course plasma exchange (PE) followed by tapering dose prednisone therapy was assessed in six children with systemic lupus erythematosus (SLE) and severe glomerulonephritis. All patients received pulse methylprednisolone therapy and three patients were treated with cytotoxic drugs prior to PE, but none had exhibited a good response. PE resulted in a rapid and sustained (greater than 1 year) remission of renal failure in the three patients with renal failure and severe glomerulonephritis. All six patients had severe nephrotic syndrome and five of six experienced a complete and sustained (greater than 1 year) remission post-PE (the sixth patient has greater than 4 month remission at the time of writing). Of interest was the high frequency of membranous [World Health Organization (WHO) Type V] and mixed membranous and diffuse proliferative SLE nephritis (WHO Type IV) on renal biopsy (4/6 patients). In addition, the severe anemia and leukopenia seen in most patients responded favorably to PE. Five of the six patients are currently managed on low-dose prednisone (0.25-0.5 mg/kg) every other day. One patient progressed to renal failure and dialysis more than 1 year post-PE. One patient required cytotoxic drug therapy post-PE (6 weeks). No significant complications were encountered; in fact, all patients eventually received their PE treatments as outpatients. We conclude that PE may provide a safe and effective therapeutic option for the treatment of severe progressive SLE nephritis in selected children who are unresponsive to steroid or cytotoxic drug therapy.

Adolescent↗