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Biomedical subjects

A J Matas

Publications and source records attributed to A J Matas.

At least 199 records · Page 11Linked to original sources

20 years or more of follow-up of living kidney donors.

The perioperative and long-term risks for living kidney donors are of concern. We have studied donors at the University of Minnesota 20 years or more (mean 23.7) after donation by comparing renal function, blood pressure, and proteinuria in donors with siblings. In 57 donors (mean age 61 [SE 1]), mean serum creatinine is 1.1 (0.01) mg/dl, blood urea nitrogen 17 (0.5) mg/dl, creatinine clearance 82 (2) ml/min, and blood pressure 134 (2)/80 (1) mm Hg. 32% of the donors are taking antihypertensive drugs and 23% have proteinuria. The 65 siblings (mean age 58 [1.3]) do not significantly differ from the donors in any of these variables: 1.1 (0.03) mg/dl, 17 (1.2) mg/dl, 89 (3.3) ml/min, and 130 (3)/80 (1.5) mm Hg, respectively. 44% of the siblings are taking antihypertensives and 22% have proteinuria. To assess perioperative mortality, we surveyed all members of the American Society of Transplant Surgeons about donor mortality at their institutions. We documented 17 perioperative deaths in the USA and Canada after living donation, and estimate mortality to be 0.03%. We conclude that perioperative mortality in the USA and Canada after living-donor nephrectomy is low. In long-term follow-up of our living donors, we found no evidence of progressive renal deterioration or other serious disorders.

Adolescent↗

Analysis of infectious complications occurring after solid-organ transplantation.

To improve our understanding of posttransplant infections, we analyzed bacterial, viral, fungal, parasitic, and other infections in 604 consecutive recipients of kidney (n = 518), kidney-pancreas (n = 82), kidney-liver (n = 3), or kidney-islet (n = 1) allografts (355 cadaveric, 14 living-unrelated, 235 living-related donors) who also received cyclosporine, azathioprine, and prednisone immunosuppression. Recipients of cadaveric grafts received additional induction immunosuppression (antilymphocyte globulin or murine monoclonal antibody OKT3). Rejection episodes were treated with high-dose steroids, and either antilymphocyte globulin or OKT3 was administered when clinically indicated. Perioperative antibiotics and posttransplant prophylactic acyclovir sodium or ganciclovir sodium, trimethoprim-sulfamethoxazole, and clotrimazole or nystatin (Mycostatin) were administered to all recipients. Two hundred thirteen patients (35.3%) were found to have had no identifiable infections, while 391 (64.7%) had either isolated bacterial (97 [16.1%]), viral (53 [8.8%]), or fungal (34 [5.6%]) infections or combination (concurrent or sequential) infections with bacterial plus viral (46 [7.6%]), bacterial plus fungal (66 [10.9%]), viral plus fungal (20 [3.3%]), bacterial plus viral plus fungal (64 [10.6%]), or bacterial plus viral plus fungal plus parasitic (11 [1.8%]) pathogens in the posttransplantation period. Renal allograft survival (percentage, actuarial method) was diminished in patients with infections at both 1 year (91% vs 83%) and 3 years (81% vs 76%) after transplantation, as was actuarial patient survival (1 year, 97% vs 92%; 3 years, 93% vs 88%). We conclude that infection remains a major cause of both patient demise and allograft loss following successful solid-organ transplantation.

Adolescent↗

Pretransplant sensitization with major histocompatibility complex class I+ class II- hepatocytes leads to accelerated skin graft rejection.

The immunogenicity of major histocompatibility complex (MHC) class I+ class II- hepatocytes is controversial. We studied the effect of pretransplant donor-specific sensitization with either purified hepatocytes (HC) or splenocytes (Spl) on subsequent skin allograft survival. Five million Percoll-purified DBA HC or 10 x 10(6) DBA Spl were injected into C57BL/6 recipients either intraperitoneally (ip) or into a sponge matrix allograft. Twelve days later, sensitized mice received a DBA skin graft. On the same day, allogeneic (DBA) and syngeneic (BL/6) skin grafts were placed on naive BL/6 mice. In naive BL/6 mice, allogeneic skin graft survival was 7.8 +/- 0.5 days (n = 4), and syngeneic survival was indefinite (n = 5). Skin graft survival (mean +/- SD in days) in recipients sensitized with hepatocytes ip was 6.0 +/- 1.2 days (n = 5) compared with 5.6 +/- 0.5 days in recipients sensitized with splenocytes ip. Similarly, graft survival in recipients that received hepatocytes into a sponge matrix allograft was 5.67 +/- 1 days (n = 6) compared with 5.2 +/- 1.1 days (n = 8) in those that received splenocytes into the sponge. There was no difference in graft survival between mice sensitized with HC vs Spl, nor between mice injected ip vs with the sponge. All sensitized mice experienced accelerated graft rejection compared with naive controls (P less than 0.000). These results demonstrate that purified MHC class I+, class II- murine HCs are immunogenic in vivo. Sensitization with donor-specific HCs led to accelerated rejection of subsequent skin grafts, similar to the accelerated rejection seen after sensitization with MHC class I+ and class II+ splenocytes.

Animals↗

Simultaneous pancreas-kidney transplant versus kidney transplant alone in diabetic patients.

The decision for simultaneous pancreas-kidney (SPK) versus kidney transplant alone (KTA) in diabetic patients with renal failure depends on the potential risks and benefits for each procedure. The purpose of this study was to compare the morbidity, mortality, and renal allograft survival in diabetic patients who underwent SPK versus KTA, and to discern the added risks associated with pancreas transplantation. Between 7/1/86 and 9/30/90, 69 primary cadaver SPK and 59 primary cadaver KTA were performed in type I diabetic patients with chronic renal failure. Antilymphocyte globulin or OKT3 was used for induction therapy, followed by standard triple therapy (prednisone, azathioprine, and cyclosporine). Patient and graft survivals were retrospectively analyzed. In addition, a detailed comparison of morbidity in those patients treated after 7/1/87 was performed (53 SPK, 49 KTA). For those less than 45 years of age (65 SPK, 42 KTA), there were no significant differences (P greater than 0.6) in the actuarial patient survival at one year (SPK 92%, KTA 95%), or two years (SPK 89%, KTA 92%), or actuarial renal allograft survival at one year (SPK 82%, KTA 83%) or two years (SPK 77%, KTA 83%). However, for those greater than 45 years old, actuarial renal allograft survival was significantly higher (P less than 0.03) in the KTA group. The mean serum creatinine levels were similar at one year (SPK 1.8, KTA 1.9 mg/d).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Mizoribine pharmacokinetics and pharmacodynamics in a canine renal allograft model of local immunosuppression.

We utilized a canine renal transplant model to estimate the first-pass extraction of mizoribine (MZB) during renal artery infusion and to compare the efficacy and toxicity of continuous intraarterial (i.a.) versus intravenous (i.v.) MZB delivery, with and without a background of oral cyclosporine. Five autotransplanted mongrel dogs with programmable, implantable pump/catheter systems were given MZB by both i.v. bolus (5 mg/kg) and i.a. infusion (5.0 mg/kg/day). Mean +/- SD elimination half-life was 3.02 +/- 0.81 hr, and the transplanted kidney removed as much as 47-59% (mean 56%) of locally infused MZB. With increasing local and systemic MZB delivery in a single autografted dog undergoing both i.a. and i.v. pump/catheter placement, renal extraction decreased from at least 47% (5.0 mg/kg/day) to 33% (7.5 mg/kg/day), finally to 18% (10.0 mg/kg/day). A dose of 3.0 mg/kg/day MZB did not significantly prolong survival of renal allograft recipients over that of untreated controls (median survival time [MST] = 8 days) when administered either locally (MST = 9 days) or systemically (MST = 12 days). All dogs receiving 4.0 mg/kg/day MZB i.a. died from rejection, and a survival advantage was still not realized (MST = 7 days). In contrast, 4.0 mg/kg/day i.v. prolonged survival over controls (MST = 14 days; P = 0.03) but not when directly compared with the i.a. group (P = 0.30), and produced death from severe debility in five of seven animals with significantly higher mean systemic MZB levels (P = 0.02). Four of six dogs receiving 5.0 mg/kg/day MZB i.a. (MST = 14 days) and two of four dogs receiving 5.0 mg/kg/day i.v. (MST = 14 days) died from severe debility, though survival in both groups was prolonged over control values (P = 0.01 and P = 0.05, respectively). Coadministration of a subtherapeutic dose of oral CsA (5 mg/kg/day) significantly prolonged the overall survival of dogs receiving MZB 4.0 mg/kg/day i.a. (MST = 23; P = 0.01) but not i.v. (MST = 11; P = 1.00), so that a significant difference in overall survival between the combined MZB i.a. + CSA and MZB i.v. + CSA groups was now realized in favor of the former (P = 0.04). We conclude that at local doses required to achieve immunosuppression, the transplanted kidney was not able to extract enough MZB to prevent death from systemic toxicity, presumably as a result of saturation of renal elimination mechanisms, so that an overall survival benefit was not realized.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Pediatric renal transplants--results with sequential immunosuppression.

Cyclosporine has improved the results of renal transplantation. In 1984, we began using it as part of a sequential immunosuppression protocol (MALG, AZA, P, and delayed administration of CsA) in our pediatric renal transplant recipients. We studied the outcome of the 131 pediatric renal transplants (less than or equal to 18 years of age at transplant) performed at our institution between June 1984 and March 1991. We compared these results with the 144 similar transplants performed since January 1980 that did not involve CsA immunosuppression. In the sequential immunosuppression group, there were 97 primary (74%) (26 [27%] cadaver, 71 [73%] living donor [LD]) and 34 (26%) retransplant (23 [68%] CAD, 11 [32%]) recipients. Age at transplant (mean +/- SD) was 7.4 +/- 5.5. Overall, 1-year actuarial graft survival was 93%; 1-year patient survival was 100%. The mean number of hospital readmissions was 3.0 +/- 3.5; 26 (20%) were readmission-free. The mean number of rejection episodes was .87 +/- 1.3 per patient; 73 (56%) were rejection-free. Importantly, LD (vs. CAD) recipients had fewer rejection episodes (P = 0.06). In the first post-transplant year, the serum creatinine level was significantly lower in primary (vs. retransplant) recipients and in LD (vs. CAD) recipients (P less than 0.05). In the 144 patients not receiving CsA, there were 129 (90%) primary (27 CAD, 102 LD) and 15 (10%) retransplant (7 CAD, 8 LD) recipients. Age at transplant was 6.9 +/- 5.3 years. The 1-year actuarial graft survival rate was 82%; the 1-year patient survival rate was 94%. The mean number of hospital readmissions was 3.3 +/- 2.3; 5 (8%) were readmission-free. The mean number of rejection episodes was 1.2 +/- 1.5; 27 (45%) were rejection-free. There was no difference in the serum creatinine level based on donor source or transplant number. Sequential immunosuppression has significantly improved patient (P = 0.003) and graft survival (P = 0.004) rates. Comparing sequential vs. non-CsA immunosuppression, there was no difference in the number of readmissions (P = 0.47), number of rejection episodes (P = 0.17), or serum creatinine level. The number of rejection-free patients was significantly lower in LD (vs. CAD) recipients (P less than 0.05). There was no evidence of progressive deterioration in renal function in the sequential (vs. non-CsA) recipients.

Adolescent↗

Recurrence of disease in patients retransplanted for focal segmental glomerulosclerosis.

The natural history of focal segmental glomerulosclerosis in patients retransplanted after loss of a primary allograft is not well established. We studied 14 patients with FSGS who were retransplanted between April 1964 and September 1990 to determine if recurrence in a second or subsequent allograft could be predicted. In this group, 8 of the primary allografts were lost to recurrent disease and 6 to rejection. None of the 6 patients who lost their primary allograft to rejection without evidence of recurrent FSGS suffered recurrent disease after retransplantation. In contrast, 3 of the 8 patients who lost their primary allograft rapidly to FSGS suffered recurrent disease and loss of function in all subsequent allografts. The remaining 5 patients had prolonged function of the primary allograft ranging between 4 and 10.5 years, despite recurrence of FSGS. Of these 5 patients, 2 have excellent renal function after retransplantation without recurrence of FSGS in the secondary allograft at 9 and 10.5 years posttransplant; 2 have lost their secondary allograft to recurrent FSGS, but are free of recurrence in the third allograft at 0.5 and 5.8 years postoperatively; 1 maintains a serum creatinine level of 1.9 mg% despite recurrence of FSGS in the secondary allograft at 1 year postoperatively. Our data show that, without recurrence of FSGS in the primary allograft, further renal transplants will be free of recurrent disease. Based on this finding, we advocate use of living-related donors for second transplants in these patients. With rapid recurrence of FSGS and subsequent accelerated loss of the primary allograft, further renal transplants carry a high likelihood of recurrent FSGS and graft loss. A substantial proportion of patients with recurrent FSGS in the primary allograft will have prolonged renal function, and are likely to have excellent results with subsequent allografts.

Adolescent↗

Cell subsets responding to purified hepatocytes and evidence of indirect recognition of hepatocyte major histocompatibility complex class I antigen. I. The role of L3T4+ T cells in the development of allospecific cytotoxicity in hepatocyte-sponge matrix allografts.

The purpose of this study was to determine the role of L3T4+, Ly2- T cells in the development of allospecific cytolytic T cells in response to purified allogeneic MHC class I+, class II- hepatocytes in vivo in hepatocyte-sponge matrix allografts (HC-SMA). In previous studies we have shown that 99% pure murine hepatocytes stimulate the development of allospecific cytolytic T cells in vitro in mixed lymphocyte-hepatocyte culture (MLHC) and in vivo in HC-SMA. Furthermore, depletion of L3T4+, Ly2- T cells from responder splenocytes inhibits the development of allo-CTLs in response to purified hepatocytes in mixed lymphocyte-hepatocyte culture. Here, using an anti-L3T4 monoclonal antibody, we tested the effect of in vivo immunodepletion of L3T4+, Ly2- T cells on the subsequent development of allo-CTLs in HC-SMA. Sponge cells were harvested on day 4 and day 12 after grafting from control and treated groups and phenotypically analyzed by FACS and immunofluorescent labelling. Splenocytes from the same animals were similarly analyzed to assess for completeness of immunodepletion. Allospecific cytotoxicity was assessed on day 12 after grafting. We found that immunotherapy with anti-L3T4 mAb was effective in depleting L3T4+, Ly2- T cells from the spleen; however, a similar number of L3T4+ cells was isolated from the sponge between control and treated groups. Furthermore, the development of allo-CTLs in response to hepatocytes in HC-SMA was completely abrogated by both local and systemic immunotherapy with anti-L3T4 mAb. We conclude from these and previous data that host or responder L3T4+, Ly2- T cells and responder accessory cells in MLHC or host macrophages in HC-SMA may participate in "indirect" recognition of hepatocyte class I antigen both in vitro and in vivo.

Animals↗

Cell subsets responding to purified hepatocytes and evidence of indirect recognition of hepatocyte major histocompatibility complex class I antigen. II. In vitro-generated "memory" cells to class I+ class II- hepatocytes.

Purified hepatocytes stimulate the development of L3T4-, Ly2+ allospecific cytolytic T cells from naive splenocytes after 5 days in primary mixed lymphocyte-hepatocyte culture (MLHC). Previous studies indicate that the immunogenicity of purified hepatocytes relates to the expression of MHC class I antigen. The purpose of the following experiments was to identify the cell subsets that specifically recognize hepatocyte MHC class I antigen. We employed primed lymphocyte testing (PLT) in order to test for a "second set" response. Cells from primary MLHC reverted to a functionally quiescent state when they were grown in culture for an additional 7-9 days. The cells were then tested for cytotoxicity or rechallenged with allogeneic, syngeneic, or "third party" hepatocytes and tested for proliferation. Allocytotoxicity was low on day 12 in MLHC, but the sensitized cell population demonstrated peak proliferation in response to allogeneic hepatocytes 48 hr after restimulation. When bulk PLT cells were immunodepleted, both L3T4+, Ly2- and L3T4-, Ly2+ T cell subsets demonstrated a "second set" response to allogeneic hepatocytes consistent with specific recognition of and retention of "memory" for hepatocyte MHC class I alloantigen.

Animals↗