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Biomedical subjects

A J Matas

Publications and source records attributed to A J Matas.

At least 307 records · Page 17Linked to original sources
PubMed1986

Transplantation of pediatric donor kidneys to adult recipients. Is there a critical donor age?

Cadaver kidneys remain a scarce resource, yet single pediatric donor kidneys are underutilized at some centers. Between 1967 and 1984, 133 single pediatric and 318 adult donor cadaver transplants were performed. Patient and graft survival, renal function, and complications in adult recipients grouped by donor age were compared. Recipient age for all groups was similar (34-36 years). Life table analysis revealed no difference in graft survival in recipients of kidneys from donors aged 2, 3, 4, 5-10, and 11-15 when compared with adult donors. Graft survival in these groups improved over time with current 1-year survival over 75%. Recipients from donors less than 24 months of age demonstrated significantly poorer results, with no kidney surviving greater than 2 months. Serum creatinine of grafts functioning greater than 6 months was similar in all groups. It is concluded that single pediatric kidneys from donors greater than 2 years of age can be successfully transplanted to adults with good long-term results.

Adolescent↗
PubMed1986

ALG treatment of steroid-resistant rejection in patients receiving cyclosporine.

Thirty-one episodes of biopsy-proved acute rejection (R) in 28 patients maintained on cyclosporine did not respond to high-dose steroids and were treated with antilymphocyte globulin (ALG). Cyclosporine was discontinued in all but three during ALG administration. (A) Twenty-four patients received 26 courses of ALG within 90 days of transplant (11 1st R, 15 2nd or 3rd). Seven treatment courses were cut short due to infection (4), ongoing R (2) and a combination of infection and rejection (1). Only 1 of 7 has a functioning graft. Of the remaining 19 full ALG courses (17 patients) (8 1st R, 11 2nd or 3rd), 13 (11 patients) responded (7 1st R, 6 greater than 1st). The remaining 6 patients lost their grafts to ongoing acute rejection. (B) Five patients were treated after 6 months posttransplant; two responded but no grafts currently function. (C) Overall 7 patients developed systemic infection (7 viruses, 1 Candida) with 1 death, and 2 additional patients developed severe thrombocytopenia and leukopenia. Patients responding to their ALG course were restarted on cyclosporine. We conclude that ALG is not as effective in reversing steroid-resistant rejection in patients maintained on cyclosporine as it has been in patients maintained on azathioprine. However, more than 50% of steroid-resistant rejection episodes are reversed.

Adolescent↗
PubMed1986

Definition, diagnosis, and management of rejection in the second to sixth months posttransplant--an overview.

CsA immunosuppression has resulted in decreased graft loss from rejection. However, rejection episodes do occur and, in fact, rejection remains as the major cause of graft loss in the CsA-treated patient. CsA, itself, has added to the differential diagnosis of renal dysfunction following transplantation. In the majority of circumstances, rejection can be differentiated from CsA nephrotoxicity as well as other causes of renal dysfunction by a combination of clinical presentation, renal scan and sonography, CsA levels, and percutaneous allograft biopsy. In some circumstances, a therapeutic trial of lowering the CsA dose may be indicated before extensive laboratory study. Most acute rejection episodes will respond to increased steroid doses. In patients with low CsA levels, increasing the CsA dose may be advised. Steroid-resistant rejection frequently responds to ALG. Patients with repeated episodes of renal dysfunction may be stabilized by using the combination of prednisone, azathioprine, and CsA.

Adrenal Cortex Hormones↗
PubMed1985

Treatment of renal transplant rejection episodes in patients receiving prednisone and azathioprine. A cost-effective approach.

Antilymphocyte globulin (ALG) has been advocated for the treatment of renal transplant rejection episodes in patients maintained on prednisone and azathioprine. Treatment with steroids (outpatient) is considerably less expensive than with ALG (inpatient), so we studied whether routine ALG was necessary. Between 3/82 and 11/83, 54 cadaver transplant recipients maintained on prednisone and azathioprine who developed a first rejection episode were randomized to receive--for treatment of their first, and if necessary second, rejection--methylprednisolone (MP) plus ALG (n = 24), or MP alone, with ALG added if treatment failed (n = 30). Treatment failure was defined as continuing deterioration on T131 iodohippuran scan, rising serum creatinine level, or lack of improvement within 7 days. There was no significant difference in patient survival, graft survival, mean number of rejections, and infection rate between the two groups: 60% (18/30) of first and 50% (10/10) of second rejection episodes responded to MP alone. We conclude that patients are not penalized by initial rejection treatment with MP. Many rejection episodes respond to steroids alone; elimination of routine ALG use will save hospitalization time and expense.

Adult↗
PubMed1985

A proposal for cadaver organ procurement: routine removal with right of informed refusal.

In order to alleviate the shortage of vital organs for transplant, we propose a system of routine removal of cadaver organs with an option of informed refusal by family. Unless an individual registered an objection during his or her lifetime, or unless the family objected to the procedure, clinicians would be permitted routinely to salvage vital organs for transplant. Our proposal charts a middle path between the current ineffective policy based on "encouraged voluntarism" and "presumed consent" policies that promise effectiveness at the cost of violating traditional ethical and legal principles. In this article, we analyze the failure of the current regime, articulate a policy of routine removal subject to the right of informed refusal, and defend this policy against several possible objections.

Cadaver↗
PubMed1985

The value of needle renal allograft biopsy. III. A prospective study.

Previous studies of the value of percutaneous renal transplant biopsy have been retrospective. We prospectively studied whether biopsy affected patient management. Thirty-five patients with elevated serum creatinine level underwent 44 biopsies in situations in which the diagnosis was in doubt. At the time of biopsy, all clinical and laboratory data were reviewed, and a proposed treatment plan was outlined. Biopsy results were available within 24 hours. We evaluated whether biopsy influenced treatment. Other than hematuria (less than 24 hours), there were no complications. Nine biopsy specimens (20.5%) were inadequate for evaluation. Forty-six percent of adequate biopsy specimens (36% of total biopsy specimens) influenced patient management. Adequate biopsy specimens resulted in a change in treatment in 10 of 19 patients receiving prednisone and azathioprine and 6 of 16 receiving prednisone and cyclosporine. The remaining biopsy specimens, although not changing management confirmed the treatment plan in ambiguous clinical situations. We conclude that percutaneous biopsy is an important aid in patient management.

Acute Disease↗
PubMed1984

Association of concurrent herpes simplex virus and cytomegalovirus with detrimental effects after renal transplantation.

Herpes simplex virus (HSV) and cytomegalovirus (CMV) infections occur frequently after renal transplantation. To determine the effect of these infections on long-term prognosis, we reviewed the charts of 558 patients who underwent primary renal transplantation between Jan 1, 1974 and Dec 31, 1978, at the University of Minnesota Hospitals, Minneapolis, for cultural evidence of these infections. The presence of HSV alone appeared to have a minimal effect on either patient or allograft survival. Positive CMV cultures were associated with decreased patient and allograft survival. Patients with HSV and CMV infections had further reduced patient and allograft survival. Lethal CMV syndrome and associated severe bacterial and fungal infections were common and frequently were the immediate cause of death in patients who had concomitant positive HSV and CMV cultures. Concurrent HSV and CMV infections in renal transplant patients may be a grave prognostic indicator, being associated with enhanced mortality and renal allograft loss.

Cytomegalovirus Infections↗
PubMed1983

The fate of the patient returned to hemodialysis after losing a renal transplant.

Previous reports have suggested that renal allograft recipients have an increased mortality rate when returned to hemodialysis. We studied the survival of patients returned to hemodialysis after losing a renal allograft and compared it with the survival of patients undergoing maintenance hemodialysis during the same period as reported by individual centers in the United States and by the European Dialysis and Transplant Association. Six-year actuarial survival of 83 patients after loss of a first transplant and of 37 patients after loss of two or more transplants compared favorably with data on survival of patients undergoing maintenance dialysis. We conclude that a transplant recipient is not at increased risk when returned to hemodialysis.

Adolescent↗
PubMed1983

Successful long-term cryopreservation of neonatal rat islet tissue.

Neonatal rat pancreatic tissue was frozen to -196 degrees C using Me2SO as a cryoprotectant and a slow freezing rate to -70 degrees C followed by immersion in liquid nitrogen. Rapid thawing was used. Viability was demonstrated by successful transplantation to streptozotocin-induced diabetic recipients. Long-term preservation, up to 4 weeks, did not demonstrably affect viability. Cryopreservation techniques may afford a method for providing a diabetic recipient the opportunity to receive a large quantity of pooled islet tissue from well-matched donors.

Animals↗
PubMed1983

The value of needle renal allograft biopsy. I. A retrospective study of biopsies performed during putative rejection episodes.

Following renal transplantation, immunosuppression is usually increased to treat presumed rejection episodes. However, a) many conditions mimic rejection in the post-transplant period, and b) many rejection episodes are irreversible. As increased immunosuppressive therapy is associated with an increased risk of infection, it would be ideal to limit antirejection therapy to only the rejection episodes that are reversible. The role of percutaneous allograft biopsy was studied as an aid to decide which patients to treat for rejection, to limit unnecessary immunosuppression and to predict allograft survival. One hundred thirty-five patients with suspected rejection underwent 206 allograft biopsies without complication. Two hundred four biopsies were available for study. Biopsies were coded on a 1-4 scale (minimal, mild, moderate, severe) for acute and chronic tubulointerstitial infiltrate and vascular rejection, as well as no rejection (e.g., recurrence of original disease). Treatment decisions were made on the basis of the biopsy combined with clinical data. All patients have been followed two years and outcome correlated with biopsy findings (death, nephrectomy, and return to dialysis defined as kidney loss). The results were the following: 1) biopsies represented changes within the kidney. Of 16 kidneys removed within one month of biopsy, no nephrectomy specimen showed less rejection than that seen on biopsy. 2) Eighty-one biopsies (39.7%) led to tapering or not increasing immunosuppression (either no rejection, minimal rejection, or irreversible changes). 3) Kidneys having either severe acute or chronic vascular rejection (less than 30% function at three months) had significantly (p less than 0.05) decreased survival three to 24 months postbiopsy than those with minimal or mild vascular rejection or tubulointerstitial infiltrate (83% function at three months). 4) Kidneys with moderate chronic vascular rejection and those with severe acute tubulointerstitial infiltrate had significantly (p less than 0.05) decreased survival at six to 24 months. 5) Kidneys with moderate chronic vascular rejection (MCV) without an acute infiltrate (ATI) had significantly better survival than those having both MCV and ATI. 6) Similarly, kidneys having severe ATI alone had better survival than those with ATI plus vascular rejection. It was concluded that a) percutaneous allograft biopsy can be done without graft loss or infection; b) biopsy represents changes throughout the kidney; c) biopsy aids in deciding when to treat for rejection and in deciding when to withhold increased immunosuppression, and d) allograft biopsy predicts the outcome of treatment of a rejection episode.

Biopsy, Needle↗