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Biomedical subjects

D E Sutherland

Publications and source records attributed to D E Sutherland.

At least 397 records · Page 22Linked to original sources

[Pancreas transplantation].

Pancreas transplantation is performed to establish a normoglycemic state, insulin-independent, in a diabetic type I recipient. Abundant evidence supports the concept that lesions developing in the eyes, nerves, kidneys and other organ systems are secondary to disordered metabolism and that restoration of normoglycemia will favorably influence their evolution. The need to provide antirejection, therapy currently confines the application of pancreas transplantation to three main groups of recipients: 1. patients who need a kidney transplant to treat end-stage diabetic nephropathy, 2. patients who received a renal transplant and have progressive systemic diabetic disease, 3. diabetics who are severely handicapped in their day-to-day lives because of difficulty with metabolic control. A significant improvement in the results of pancreas transplant has progressively occurred worldwide and several controlled studies are beginning to provide evidence of the favorable effect on secondary complications. The quality of life of these patients is also improved by a functioning graft.

Blood Glucose↗

The effects of pancreas transplantation on the glomerular structure of renal allografts in patients with insulin-dependent diabetes.

The microvascular complications of diabetes mellitus may be caused, in part, by poor glycemic control. Diabetic patients who have received renal allografts may have new glomerular lesions that are manifested structurally by increases in mesangial and glomerular volume. Successful pancreas transplantation produces long-term normoglycemia and provides a unique opportunity to evaluate the impact of the normalization of the blood glucose level on the development of the renal lesions typical of diabetes mellitus in transplanted kidneys. We obtained biopsy specimens from the functioning renal allografts of 12 patients with insulin-dependent (Type I) diabetes before successful pancreas transplantation (performed one to seven years after renal transplantation) and repeated the biopsy at least 1.9 years later. In renal biopsy specimens obtained before pancreas transplantation, the mesangial volume was normal or modestly increased and the glomerular basement membrane was moderately thickened. At follow-up, no progression could be detected in any structural measure in the glomerulus. Furthermore, the recipients of pancreas transplants had smaller glomerular volumes than 13 matched diabetic patients who were recipients of renal allografts but who did not undergo pancreas transplantation (mean +/- SD, 1.80 +/- 0.55 vs. 2.47 +/- 0.73 x 10(6) microns 3; P = 0.02) and showed markedly less mesangial expansion (mesangial-volume fraction, 0.19 +/- 0.07 vs. 0.31 +/- 0.10 microns 3 per cubic micrometer; P = 0.004). We conclude that successful pancreas transplantation is associated with significantly less severe diabetic glomerulopathy in kidneys previously transplanted into diabetic patients. These data support the hypothesis that normoglycemia can prevent the progression of diabetic glomerulopathy in humans.

Adult↗

Cold storage preservation of pancreatic tissue prior to and after islet preparation in a dog autotransplantation model.

Utilizing an intrasplenic canine islet autotransplant model, the effects of cold storage preservation on pancreatic tissue prior to and after collagenase dispersion were examined. A control series, in which freshly retrieved and prepared tissue was transplanted, yielded a 75% success rate (6/8). In contrast, when the pancreas was stored in modified silica gel filtered plasma (SGF I) for 24 hr, no autotransplant was successful (0/6). However, when the islet tissue was prepared following pancreatectomy and then stored in a mannitol-containing modification of SGF (SGF III), autotransplantation was successful in 83% (5/6) after 24 hr of preservation and in 60% (3/5) after 48 hr of preservation. Similarly, the islet tissue was stored in a hyperkalemic hydroxyethyl starch solution (HES) and this was successful in 20% (1/5) after 24 hr of preservation and in 50% (1/2) after 48 hr of preservation. Cold storage preservation techniques for the pancreas prior to islet isolation need to be refined, but dispersed islet-enriched pancreatic tissue can be successfully maintained at 4 degrees C for up to 48 hr prior to transplantation in dogs using established pancreas preservation solutions.

Animals↗

Experimental pancreatic preservation prior to islet isolation and transplantation.

Preservation of the Lewis rat pancreas prior to islet isolation was accomplished by initial intraductal distension with the University of Wisconsin (UW) hydroxyethyl starch-lactobionate solution to which collagenase had been added, followed by simple cold storage at 4 degrees C for 0, 3, 12, 24, and 48 hr (n = 16-21 at each interval). The pancreases were then processed by digestion and mechanical dispersion to produce free islets of Langerhans. The mean islet yields (+/- standard errors of the means) were controls = 819 +/- 58 (n = 21), 3 hr = 867 +/- 51 (n = 20), 12 hr = 770 +/- 71 (n = 16), 24 hr = 805 +/- 62 (n = 18), and 48 hr = 722 +/- 55 (n = 16). None of these means differed significantly. The islets from pairs of donor pancreases (mean dose of islets = 1586 +/- 72) were transplanted intraportally into single isogeneic recipients with streptozotocin-induced diabetes (plasma glucose greater than 400). The preservation interval directly influenced the outcome of these islet isografts in the following manner: (i) Rates of functional success (nonfasting glucose less than 200 mg/dl) were 100% after storage times of 0 hr (n = 10), 3 hr (n = 8), and 12 hr (n = 8); 86% with a storage time of 24 hr (n = 7); and 0% after 48 hr (n = 8). (ii) Return of euglycemia was increasingly delayed with increasing preservation intervals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Modulation of MHC class I antigen decreases pancreatic islet immunogenicity.

Pretreatment regimens directed at reducing the immunogenicity of pancreatic islets have emphasized the elimination or alteration of the major histocompatibility complex (MHC) class II-positive dendritic cells within the islet. Unfortunately, the efficacy of such pretreatment regimens has been extremely variable and the relative contribution of the dendritic cells to the overall immunogenicity of pancreatic islets has remained ambiguous. Recent evidence has suggested that the MHC class I antigen present on the endocrine cells within the islets may play an important role in the alloimmune response. This study utilized the in vitro mixed lymphocyte-islet co-culture system to determine if pretreatment of whole islets with an anti-MHC class I monoclonal antibody specific to the donor strain would block the generation of cytotoxic T lymphocytes (CTL) in the in vitro mixed lymphocyte-islet coculture. Pretreatment of B10.BR (H-2k) and DBA/2J (H-2d) islets with an allospecific anti-MHC class I monoclonal antibody blocked the generation of allospecific CTL when the pretreated islets were placed into coculture with C57Bl/6 (H-2b) splenocytes. If such a pretreatment regimen is similarly effective in vivo, it could potentially be used as an antirejection strategy in pancreatic islet allotransplantation.

Animals↗

A simple method of canine pancreatic islet isolation and intrahepatic transplantation.

Clinical pancreatic islet transplantation has been impeded by the inability to isolate an adequate mass of functional tissue that will ameliorate diabetes. A simplified method of canine islet isolation was developed that allowed for either intrasplenic or intrahepatic transplantation. Following total pancreatectomy, parenchymal digestion was accomplished by intraductal collagenase perfusion and stationary incubation. The digested tissue was dispersed by filtration through a steel mesh (400 microns), washed, and separated on a discontinuous dextran density gradient. Enhanced islet tissue (2-4 ml) was recovered from the uppermost interface of the gradient and autotransplanted. The islet isolation procedure was tested in two series of dogs undergoing either intrasplenic or intrahepatic engraftment. Immediate and sustained normoglycemia (plasma glucose less than 200 mg%) was obtained in 5 of 8 dogs (63%) in the intrasplenic group and 6 of 8 dogs (75%) in the intrahepatic group. The mean fasting plasma glucose concentration 2 weeks after transplantation was 102.8 +/- 6.4 mg% in the intrasplenic group and 103.3 +/- 8.4 mg% in the intraportal group. The mean IVGTT K-values 2 weeks after transplantation were -1.41 +/- 0.35% and -1.21 +/- 0.13%, respectively. On the basis of insulin content, the islet yield was 33.0 +/- 3.7% of the total pancreas in the intrasplenic group and 33.0 +/- 3.1% in the intrahepatic group. Islet mass was enhanced 10.2 +/- 1.5 and 20.0 +/- 6.2 fold, respectively, on the basis of insulin/amylase ratios. The success rate in this canine model compared favorably with previously published results from other laboratories.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

A 10-year experience with 290 pancreas transplants at a single institution.

Since our report at the 1984 American Surgical Association meeting of 100 pancreas transplants from 1966 through 1983, another 190 have been performed. The current series, begun in 1978, now numbers 276 cases, and includes 133 nonuremic recipients of pancreas transplants alone (PTA), 46 simultaneous pancreas/kidney transplants (SPK), and 97 pancreas tranplants after a kidney transplant (PAK). Duct management techniques used were free intraperitoneal drainage in 44 cases, duct occlusion in 44, enteric drainage in 89, and bladder drainage in 128. The 1-year patient and graft survival rates in the entire cohort of 276 were 91% and 42%. One-year patient survival rates were 88% in the first 100, 91% in the second 100, and 92% in the last 76 cases; corresponding 1-year graft survival rates were 28%, 47%, and 56% (p less than 0.05). A prospective comparison of bladder drainage (n = 82) versus enteric drainage (n = 46) in PAK/PTA cases since November 1, 1984 favored bladder drainage (1-year graft survival rates of 52% vs. 41%) because of urinary amylase monitoring. The best results were in recipients of primary SPK bladder-drained transplants (n = 39), with a 1-year pancreas graft survival rate of 75%, kidney graft survival rate of 80%, and patient survival rate of 95%. Logistic regression analysis, with 1-year graft function as the independent variable, showed significant (p less than 0.05) predictors of success (odds ratio) to be technique: bladder drainage (5.8) versus enteric drainage (2.5) versus duct injection (1.0); category: SPK (6.0) versus PAK from same donor (3.2) versus PAK from different donor (1.2) versus PTA (1.0); and donor HLA DR mismatch: 0 (5.0) versus 1 (2.5) versus 2 (1.0) antigens. On April 1, 1989, 90 patients had functioning grafts (60 euglycemic and insulin-free for more than 1 year, 10 for 5 to 10 years); these, along with 24 others whose grafts functioned for 1 to 6 years before failing, are part of an expanding cohort in whom the influence of inducing a euglycemic state on pre-existing secondary complications of diabetes is being studied. Only preliminary data is available. In regard to neuropathy, at more than 1 year after transplant in patients with functioning grafts, conduction velocities in some nerves were increased over baseline. In regard to retinopathy, deterioration in grade occurred in approximately 30% of the recipients by 3 years, whether the graft functioned continuously or failed early, but thereafter retinopathy in the patients with functioning grafts remained stable.(ABSTRACT TRUNCATED AT 400 WORDS)

Diabetes Mellitus↗

Cold-storage preservation of the canine and rat pancreas prior to islet isolation.

Cold-storage preservation of the canine pancreas prior to islet isolation has previously been noted to reduce the intrasplenic islet autograft success rate; but the mechanism of this deleterious effect has not been determined. We undertook a study in both outbred dogs and Lewis (RT1-1) rats to determine the influence of cold-storage preservation interval, preservation solution, and flushing technique on islet yield and islet viability. The preservation solutions used were those that had proved most efficacious in preserving segmental canine pancreases--namely, the modifications of silica gel fractionated plasma (SGF-III and SGF-IV) and an hydroxyethylstarch/lactobionate solution (UW-1). In the first set of experiments, the traditional vascular flush was used; this was followed by storage at 4 degrees C. After brief periods of preservation (3 hr in the rat, 12 hr in the dog) there was a significant (P less than 0.006) reduction in islet yield. The reduced yields were similar with each solution tested, were made worse with increasing intervals of storage, and resulted in a significant reduction in autograft success rate. The second set of experiments examined the effect of using an intraductal flush prior to preservation, along with the effect of adding collagenase to the preservation fluid. Islet yields were maintained at control values in both animal models using preservation intervals of up to 24 hr. These islet yields produced auto- or isograft success rates similar to those obtained by transplanting freshly obtained tissue; verifying adequate islet viability. We recommend that a pre-storage ductal flush technique be used for cold-storage preservation of the pancreas prior to islet isolation and transplantation.

Animals↗

Long-term survival following kidney transplantation in 100 type I diabetic patients.

Between December 1966 and April 1978, 265 uremic patients with type I diabetes received primary renal allografts at the University of Minnesota. One hundred of the diabetic patients were alive with a functioning graft 10 years after transplantation. The actual 10-year patient and primary graft functional survival rates overall were 40% and 32%, respectively. For recipients of HLA-identical sibling (n = 45), mismatched living-related (n = 121), and cadaver donor grafts (n = 99), the actual 10-year patient survival rates were 64%, 33%, and 36%, respectively, and the actual 10-year graft functional survival rates were 62%, 28%, and 22%, respectively. The differences in patient and graft survival rates between HLA-identical graft recipients and recipients of mismatched related and cadaver grafts were significant (P less than 0.001). Of the 100 patients who survived into a second decade, at 15 years posttransplant 51% were alive, and 41% had functioning grafts. For recipients of HLA-identical sibling, mismatched living-related donor grafts, and cadaver donor grafts who survived 10 years, 47%, 57%, and 43%, respectively, were alive at 15 years, and 31%, 45%, and 43%, respectively, had functioning grafts. For recipients who made it to the second decade, patient and primary graft survival rates thereafter were not statistically different by donor source. Twenty-three patients died in the second decade after transplantation, 10 of cardiovascular disease. Twenty-five patients lost graft function in the second decade, 19 from death with a functioning graft. In regard to diabetic complications, recurrence of diabetic nephropathy was common, but only two patients lost graft function solely for this reason. In 21 patients (42 eyes) followed prospectively for 10 years, visual acuity deteriorated in 26%, was stable in 64%, and improved in 10% of eyes. Neurophysiological test results indicated that correction of uremia does not stop the progression of diabetic neuropathy in recipients of kidney transplants alone. Even without cyclosporine, nearly two-thirds of recipients of HLA-identical kidney grafts, more than one-quarter of recipients of mismatched living-related donor grafts, and more than one-fifth receiving cadaver grafts enjoyed an extension of life for more than 10 years.

Age Factors↗

Renal transplantation between living-related sibling pairs matched for zero-HLA haplotypes.

The functional survival rates of kidney grafts from zero-HLA haplotype-matched sibling pairs are similar to one-haplotype-matched pairs and superior to cadaver grafts. From January 1980 to March 1988, 318 primary renal transplants from sibling donors (151 matched for two, 130 for one, and 37 for zero HLA haplotypes), and 352 cadaver graft transplants were performed at the University of Minnesota. The renal graft survival rates at two years were 94%, 91%, and 94% for the 2, 1, and 0-haplotype pairs versus 75% for cadaver graft recipients (P less than 0.04). When analyzed across the different immunosuppression protocols the same trends held up, similar graft functional survivals for 1- and 0-haplotype-matched pairs both being superior to cadaver graft recipients. The graft functional survival rates at two years of recipients of 0-haplotype-matched sibling donor grafts (n = 37) was 94% versus 80% for recipients of cadaver donor grafts matched for greater than or equal to 4 HLA antigens. In addition, for recipients of 0-haplotype-matched grafts, hospital stay was shorter, fewer patients required dialysis posttransplant, and, despite a slightly higher incidence of rejection episodes (51% versus 40%, P = ns), the creatinine values one year posttransplant were significantly lower (1.5 mg/dl versus 1.9 mg/dl, P less than 0.02) than those of recipients of cadaver grafts matched for greater than or equal to 4 HLA antigens. These data support the use of cadaver grafts for patients not having a willing sibling donor, and the use of all willing sibling donors, whether or not they are a zero-haplotype match, for patients fortunate to have that family commitment.

Antilymphocyte Serum↗

The presence of nicotine on root surfaces of periodontally diseased teeth in smokers.

There is a growing body of scientific evidence to support the concept that the use of tobacco products significantly contributes to the progression of periodontal disease or is detrimental to healing following periodontal therapy. Several studies have shown toxic effects of nicotine on peripheral circulation and the immune response. The purpose of the present study was to identify and compare the quantity of nicotine present on root planed and nonroot planed surfaces of teeth from smokers. Twenty-nine single-rooted teeth from 11 smokers were extracted, brushed clean, and the roots sectioned longitudinally. The respective halves were either left untreated (Group A) or thoroughly root planed (Group B). Pulpal tissue was removed and the individual root sections weighed. Each half was extracted for nicotine using a methylene chloride technique. Quantification was performed using high pressure liquid chromatography (HPLC) and the sections compared on a nicotine per root weight basis. Results showed a greater amount of nicotine present on non-root planed sections than on treated sections, although some treated specimens revealed small amounts of the substance. These findings suggest that nicotine is present on the root surface but is largely removed by thorough root planing. Its presence is not surprising in light of the recent finding that nicotine and cotinine, the major metabolite of nicotine, are found in gingival crevicular fluid. Recent studies have shown a particularly harmful effect of nicotine on fibroblasts. Its presence on root surfaces may, therefore, impair wound healing and alter the host response in periodontal disease. The use of tobacco products in conjunction with periodontal therapy may interfere with optimal healing and/or lead to further periodontal breakdown.

Chromatography, High Pressure Liquid↗

Cotinine in saliva and gingival crevicular fluid of smokers with periodontal disease.

A study was undertaken to determine the presence of cotinine, a metabolite of nicotine, in the saliva and gingival crevicular fluid of smokers with periodontal disease. Saliva and crevicular fluid samples were obtained from 16 habitual cigarette smokers and analyzed by High Performance Liquid Chromatography (HPLC) for the presence of cotinine. Thirteen non-smokers with periodontal disease served as controls. There was no evidence of cotinine (within our detection levels) in either the saliva or crevicular fluid of any of the nonsmokers. Cotinine, in a wide range of concentrations, was detected in the saliva and crevicular fluid in all of the 16 cigarette smokers. The presence of a nicotine metabolite in the saliva and gingival crevicular fluid reflects the extent of the systemic distribution of nicotine in smokers. The vasoactive properties of nicotine are well known and may possibly affect the pathogenesis of periodontal disease.

Acetanilides↗

Influence of serum amylase and plasma glucose levels in pancreas cadaver donors on graft function in recipients.

In a series of 101 pancreas transplants from brain cadaver donors, serum amylase levels were determined preoperatively in 47 donors, and plasma glucose levels were monitored in 94 donors. Eighty-six percent of the donors died from head injury and 14% from asphyxia. No donors had a history of diabetes or pancreatitis, and the pancreas was grossly normal in all donors. Of the 47 cadaver pancreas donors in whom serum amylase levels were measured, the values of 20 donors were elevated (110-994 IU/L), and the values of 11 donors were greater than 300 IU/L. In 51 of 94 braindead cadaver pancreas donors in whom plasma glucose determinations were made, hyperglycemia was present (200-980 mg/dl). Early posttransplant pancreas-graft function was excellent in all recipients except for 5 patients in whom the grafts had to be removed for reasons not related to donor serum amylase and plasma glucose levels. Hyperamylasemia and hyperglycemia are probably not contraindications for cadaver pancreas organ donation unless overt pancreatic trauma, pancreatitis, or a history of diabetes is present.

Amylases↗