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Biomedical subjects

R M Hoffmann

Publications and source records attributed to R M Hoffmann.

At least 55 records · Page 3Linked to original sources
PubMed1992

T lymphocytes from patients with primary biliary cirrhosis produce reduced amounts of lymphotoxin, tumor necrosis factor and interferon-gamma upon mitogen stimulation.

Primary biliary cirrhosis (PBC) is considered an autoimmune disease characterized by destruction of small intrahepatic bile ducts by lymphocytes. Altered functions of these lymphocytes might reflect an abnormal immune response leading to tissue damage. We investigated lymphokine secretion by mitogen-stimulated T lymphocytes from the liver biopsies of patients with PBC and for comparison also peripheral blood. In PBC, diminished synthesis of lymphotoxin (TNF beta), tumor necrosis factor (TNF alpha) and interferon-gamma (IFN gamma) was found both in T-cell lines from liver tissue and in peripheral blood. The reduction was most prominent for TNF beta in early histological stages of PBC, and appeared to be a stable phenomenon when T cells were tested after long-term tissue culture. Analysis of mRNA levels indicates a possible link between reduced TNF beta production and a defect in interleukin-2 transcription. The data suggest that diminished lymphokine production in patients with PBC may play an important role in the immunopathogenesis of this disease.

Adult↗
PubMed1992

The use of UW solution in clinical transplantation. A 4-year experience.

The development of the University of Wisconsin (UW) cold storage solution has extended safe preservation of the liver and pancreas from 6 to 24 hours or more. From May 1987 until November 1991, 288 livers and 163 simultaneous pancreas/kidney transplants were performed using UW solution. The mean preservation times were: liver, 12.7 +/- 4.4 hours, pancreas 17.2 +/- 4.4 hours, and kidney, 19.2 +/- 4.3 hours. Included in this series were 35 reduced-sized liver transplants, 7 cluster transplants, and 132 combined liver/pancreas retrievals. No differences in allograft function or graft-related complications were seen in organs preserved for less than or longer than 12 hours or in grafts from combined liver/pancreas retrievals. All pancreas/kidney transplants and most liver transplants were performed semi-electively. Actuarial 1-month patient and graft survival after liver transplantation was 91.4% and 80.2%, and at 4 years was 74.0% and 62.0%, respectively. After pancreas/kidney transplantation, the actuarial patient survival at 1 month and 4 years was 99.4% and 90.5%, respectively, whereas pancreatic and renal allograft survival at 1 month was 97.5% and 96.8%, and at 4 years was 83.0% and 83.4%, respectively. The ability to extend preservation times with UW solution has many advantages; however, the most important contribution of UW solution to clinical transplantation has been the increased utilization of scarce donor organs for more recipients because the previously imposed constraints on preservation time have been removed.

Adenosine↗
PubMed1992

The effect of donor age, recipient age, and HLA match on immunologic graft survival in cadaver renal transplant recipients.

We retrospectively analyzed 526 primary cadaver recipients transplanted at a single center to identify pretransplant variables that predict long-term survival with multivariate analysis. All recipients received at least three random blood transfusions and were treated under a quadruple-therapy protocol consisting of ALG, azathioprine, prednisone, and cyclosporine. Of 526 consecutive transplants, 86 grafts were lost from acute or chronic rejection. Thirteen grafts were lost for nonimmunologic reasons and 35 recipients died with a functioning graft. A total of 273 patients (52%) experienced at least one episode of acute rejection. Donor age ranged from 3 to 64 years, with 62% of donors less than 30 years of age and 9% of donors over 50 years of age. Donor age was not predictive of long-term graft survival and neither was the difference between donor and recipient age. Recipient age was predictive of subsequent immunologic graft less, with younger recipients at greater risk (P = 0.011). The rate of first rejection was also inversely related to recipient age, with younger recipients rejecting earlier (P = 0.0001). The degree of DR mismatch was the only other significant predictor of long-term graft success (P = 0.013). Transplant survival correlated with the degree of DR mismatch: 2 DR mismatch was the worst, 1 DR mismatch was intermediate and 0 DR mismatch was the best (P = 0.02). A, B, AB, and BDR did not influence long-term graft outcome. In our center, donor age does not predict graft failure. Younger recipients have a higher rate of early rejection and, combined with a poor DR match, are at higher risk for long-term graft failure.

Adult↗
PubMed1991

Analysis of the interchangeability of a dental articulator.

A series of Dentatus ARL articulators and gauge blocks were tested for the reliability of the system to reproduce articulator mountings. Points of occlusal contact were measured at several locations on a set of casts. Analysis of the data indicated that the location of the occlusal contacts and the gauge block used were critically related to the results. Further studies to quantify the measurement error and to carefully explore where this system could be used are needed.

Analysis of Variance↗
PubMed1991

The predictive value of donor liver biopsies for the development of primary nonfunction after orthotopic liver transplantation.

Methods of accurately assessing the suitability of donor livers prior to transplantation are required if the incidence of primary nonfunction (PNF) is to be reduced. This study evaluated the ability of donor liver biopsies to predict the development of primary nonfunction after transplantation. From June 1987 until May 1990, 170 liver transplants were performed in 147 patients. A total of 124 donor liver biopsies were obtained and divided into three groups. Group 1 biopsies (n = 77) were obtained after revascularization of the liver, group 2 biopsies (n = 19) were obtained prior to donor hepatectomy but examined only after implantation, and group 3 biopsies (n = 28) were obtained as in group 2, but were examined prior to implantation. Three of 89 (3.4%) livers interpreted as having normal histology developed primary nonfunction, while one of 26 (3.8%) biopsies interpreted as having a minimal or moderate amount of fatty infiltration developed primary nonfunction. PNF occurred in 7 of 8 livers with severe fatty infiltration (3), hydropic degeneration (3), and centrilobular necrosis (1). A fourth liver with hydropic degeneration and poor function ultimately failed requiring retransplantation 8 weeks later. Analysis of liver function revealed progressive elevation in aspartate-aminotransferase, alanine-aminotransferase, lactate dehydrogenase, and serum ammonia (NH3) with increasing degrees of fatty infiltration. Donor age and weight was also found to be significantly higher in livers with fatty infiltration. This study suggests that donor liver biopsies demonstrating normal histology or minimal-to-moderate fatty infiltration function adequately, but that donor livers with severe fatty infiltration or hydropic degeneration function poorly and should not be transplanted.

Biopsy↗
PubMed1989

Liver transplantation in infants and children.

Orthotopic liver transplantation has become an accepted form of therapy for advanced liver disease. Over a 44-month period, we performed 27 liver transplants in 25 pediatric recipients, including 14 infants (mean age, 7.2 months; mean weight, 5.9 kg) and 11 children (mean age, 9.0 years; mean weight, 34.8 kg). Indications for transplantation were biliary atresia (16), tyrosinemia (3), chronic hepatitis with cirrhosis (2), fulminant hepatic failure (2), and one patient each with Wilson's disease and primary hepatoma. Eighteen patients (72%) had undergone a previous laparotomy, including 19 Kasai procedures in 13 patients with biliary atresia. The average time on the waiting list was 26.8 days (range, 1 to 60), and no patients died while awaiting transplantation. Mean preservation time was 6.9 hours (range, 2 to 13.5), employing cold storage with Collin's solution (16), or more recently, UW solution (11). Urgent liver transplantation was performed in seven cases (25.9%), although at present, we perform liver transplantation as a scheduled semielective procedure with extended preservation times in stable patients. The recipient hepatectomy and orthotopic liver transplantation were performed by standard techniques, with venous bypass used in three cases. Biliary reconstruction was performed with a Roux limb in 16 and via choledochocholedochostomy in ten cases, while arterial reconstruction was end-to-end hepatic artery in 21, and aorto-aortic anastomosis in the remaining six. Two hepatic artery thromboses (7.4%) and two biliary complications (7.4%) occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Combined cold storage-perfusion preservation with a new synthetic perfusate.

Based upon encouraging experimental results, we began employing a synthetic perfusate for cadaver kidney preservation. The new perfusate contains hydroxyethyl starch (HES) as the sole colloid for oncotic support; 107 cadaver kidneys were preserved and transplanted (93 primary, 14 nonprimary) using the HES solution and were compared with our previous experience of 180 cadaver kidneys (161 primary, 19 nonprimary) preserved and transplanted utilizing an albumin-based perfusate. All cadaver kidneys were locally harvested and preserved by machine perfusion. Donor and preservation characteristics in the HES (n = 61) and the albumin (n = 101) groups were comparable, with a mean preservation time of 30.9 hr. Cold storage in combination with hypothermic pulsatile perfusion (HPP) preservation was performed more often in the HES group (68.2% vs. 31.1%, P less than 0.001). Recipient characteristics were also comparable, and all received quadruple immunosuppressive therapy with sequential/Minnesota antilymphoblast globulin/(MALG)/cyclosporine. After primary transplantation, the incidence of immediate function (82.6% vs. 89.2%), preservation-related dialysis (14.9% vs. 8.6%), and primary nonfunction (2.5% vs. 0) were similar between the 2 groups, with trends favoring the latter HES data. One-month serum creatinine (1.8 vs. 1.7 mg/dl) and graft survival (95% vs. 97.8%) also were comparable. Similar trends were present in the retransplant group, including a significantly lower 1-month serum creatinine in the HES group (2.2 vs. 1.5 mg/dl; P less than 0.05). The preservation-related dialysis rate did not differ between primary and nonprimary transplants. Primary nonfunction has not occurred with our new perfusate. Combined cold-storage-HPP preservation with HES perfusate offers advantages over standard retrieval technology and provides excellent immediate allograft function.

Albumins↗