bluuebunny/crossref_metadata_2025 huggingface dataset:
Abdominal Intratesticular Islet-Xenograft Survival in Rats
Authors: Selawry Helena P , Whittington Karen B , Bellgrau Donald
Published: September 2013

We investigated the survival of islet xenografts in the abdominal testes of normal, diabetes-resistant ACI and Wistar-Lewis (W-L) and in diabetes-prone BB/Wor rats. Islets were isolated from hamster donors, and after a period in tissue culture, they were injected into the abdominal testes of diabetic rats. Postoperatively, the rats were divided into two treatment groups. Four ACI rats received antilymphocyte serum (ALS) injections over a period of 30 days, and 13 ACI, 15 W-L, and 13 BB/Wor rats were given cyclosporin (CsA) according to the following regimen: 25 mg/kg i.p. for 7 days, then 7 mg/kg i.p. for 23 days. On day 30, immunosuppression was stopped. The results showed that none of the ALS-treated ACI rats remained normoglycemic for >9 days. However, CsA therapy resulted in an extended mean duration of normoglycemia in the ACI and W-L rats of 160.0 ± 36.0 and 131.0 ± 31 days, respectively. By contrast, the mean duration of normoglycemia in the BB/Wor rats was 33.0 ± 4.0 days. Furthermore, all of the BB/Wor rats reverted to diabetes after CsA was stopped. Therefore, the concomitant administration of an antigenic islet xenograft with CsA led to a state of unresponsiveness only in diabetes-resistant but not in diabetes-prone rats. Because the BB/Wor rats have demonstrable T-lymphocyte dysfunction, they may be unable to generate the CsA-induced suppressor T-lymphocytes required for the long-term acceptance of the graft by the host.
Quality of Life in Diabetic Patients After Combined Pancreas-Kidney or Kidney Transplantation
Authors: Nakache Richard , Tydén Gunnar , Groth Carl-Gustav
Published: September 2013

The quality of life was compared between 14 combined pancreas-kidney–transplant patients (group 1) and 16 diabetic kidney-transplant patients (group 2). Minimum follow-up was 2 yr with functioning grafts. Two-thirds of both groups' patients were working, but 90% in group 1 and 50% in group 2 had full-time occupations. Also 7% in group 1 and 43% in group 2 had to modify their activity posttransplantation. The amount of lost workdays was calculated during periods of 2 yr preand posttransplantation: the figure decreased by 44% in group 1 (from 278 to 155) and was unchanged in group 2 (from 211 to 213). The number of sickness pensions paid increased from 28% of the patients pretransplantation to 42% in October 1987 in group 1 and from 20 to 62% in group 2. Over the last 2 yr, an average of 12 days of hospitalization were necessitated in group 1 compared to 25 days in group 2. When physical activity was evaluated, both groups judged their present state of health as good or very good (group 1, 78%; group 2, 73%). In group 1, 80% claimed they had recovered the same or better quality of life as they had before renal failure, compared to 50% in group 2. The investigation showed that group 1 seemed to achieve a better quality of life than group 2; all combined pancreas-kidney-transplant patients returned to a normal diet and achieved a less restricted life-style.
Markers for Pancreas-Graft Rejection in Humans
Authors: BrattstrÖm Christina , Tydén Gunnar , Reinholt Finn P , Bohman Sven-Olof , Borgström Anders , Bäckman Lars , Bolinder Jan , Groth Carl-Gustav
Published: September 2013

Rejection episodes were studied in 15 patients, in whom no kidney graft could serve as a marker for rejection, subjected to pancreas transplantation with pancreatoenterostomy and temporary exteriorization of the pancreatic juice (10 pancreas alone, 3 pancreas after kidney, and 2 combined pancreas and kidney in which the kidney was not functioning.) Twelve patients (80%) had a total of 18 rejection episodes. In the first 11 patients, 13 rejection episodes were diagnosed by a decline in amylase activity in the pancreatic juice, whereas in the next 4 patients, 5 rejection episodes were diagnosed by positive cytology in the pancreatic juice. Neopterin in pancreatic juice and immunoreactive anionie trypsin in serum showed promise as rejection markers, whereas serum neopterin, serum amylase, and serum immunoreactive cationic trypsin did not. Unspecific signs of rejections were an increase in white blood cell count, clinical symptoms such as fever, abdominal pain, and arthralgia. All acute rejection episodes were successfully reversed by antirejection treatment. However, late rejections diagnosed by impaired endocrine function were seen in 6 of the 15 (40%) patients, and the prognoses for these rejections were worse: 4 patients (27%) lost their grafts because of chronic rejections, and 2 patients still had impaired endocrine function.
Use of UW Solution in Pancreas Transplantation
Authors: D'Alessandro Anthony M , Stratta Robert J , Sollinger Hans W , Kalayoglu Munci , Pirsch John D , Belzer Folkert O
Published: September 2013

We have recently reported successful 72-h preservation of the canine pancreas with a new ••ld-storage solution developed at the University of Wisconsin (UW solution). Over 10 mo, we performed 11 combined pancreas-kidney and 4 isolated-pancreas transplants with this solution. In situ cooling of the donor pancreas was performed with 1000 ml of UW solution followed by ex vivo perfusion with an additional 250–500 ml. Graft preservation times ranged from 3 to 19 h (mean 10.2 h). Pancreas transplants were vascularized whole-organ grafts with pancreaticoduodenocystostomy. Early graft function was excellent as assessed by immediate insulin independence, high urinary amylase and low serum amylase levels, and a technetium perfusion index indicating good pancreatic blood flow. There were no episodes of primary nonfunction, graft pancreatitis, or vascular thrombosis. Actuarial patient and graft survival at 1 mo was 92.9%. We conclude that UW solution provides excellent early graft function for up to 19 h of cold storage. Based on previously reported data on its efficacy in liver and kidney preservation, UW solution seems ideally suited as a universal intraaortic flush and cold-storage solution.
Recurrence of Disease in Pancreas Transplants
Authors: Sutherland David ER , Goetz Frederick C , Sibley Richard K
Published: September 2013

In a series of 200 pancreas transplants with 6 mo to >9 yr of follow-up, recurrence of disease was identified as the cause of graft failure in 8 cases, all in non- or minimally immunosuppressed recipients of transplants from identical twin (n = 3) or HLA-identical sibling (n = 5) donors. Recurrence of disease was defined as selective loss of β-cells; other endocrine cell types persisted and appeared normal within the islets of the graft. Isletitis was present in islets with residual β-cells during the evolution of the process in all nonimmunosuppressed and in some immunosuppressed recipients, but isletitis resolved in all cases in which β-cell destruction was complete and also resolved in some cases in which residual β-cells were retained after the introduction of or an increase in immunosuppression. Recurrence of disease can be prevented by immunosuppression, and 2 recipients of identical twin grafts and 12 recipients of grafts from HLA-identical siblings had functioning grafts as of March 1988, the longest >7 yr. The process has not been observed in patients in whom full-dose immunosuppression has been used, including HLA-identical siblings, and this may be the reason no cases of recurrence of disease have been identified in recipients of cadaveric grafts. Alternatively, the observations are consistent with, but not proof of, the hypothesis that recurrence of disease (autoimmune isletitis leading to diabetes) is a major histocompatibility complex-restricted phenomenon.
Effects of Pancreas Transplantation on Metabolic and Hormonal Profiles in IDDM Patients
Authors: ÖStman Jan , Bolinder Jan , Gunnarsson Rolf , Brattström Christina , Tydén Gunnar , Wahren John , Groth Carl-Gustav
Published: September 2013

The diurnal patterns of relevant metabolites and hormones in five pancreas-kidney-transplanted patients (aged 36 ± 2 yr, mean ± SD) with insulindependent diabetes mellitus (IDDM) were compared with those in five kidney-transplanted nondiabetic patients (aged 28 ± 2 yr). The groups were matched for body mass and current dose and type of immunosuppressive treatment. The serum creatinine levels did not differ between the two study groups, but the serum urea level in the nondiabetic patients was slightly but significantly higher than in the diabetic patients. In the pancreas-kidney-transplanted group the investigation was performed 8–47 mo posttransplantation; in the kidney-transplanted nondiabetic patients, 12–18 mo posttransplantation. The mean 24-h levels and rhythms of blood glucose, free fatty acid, 3-hydroxybutyrate, and alanine did not differ between the groups. The mean 24-h levels of blood lactate and glycerol were moderately but significantly higher in the pancreas-kidneytransplanted diabetic patients. At fasting, the level of serum immunoreactive insulin was more than twice as high in the pancreas-kidney-transplanted patients, whereas the plasma C-peptide levels did not differ significantly between the two groups. The mealinduced increases in serum insulin as well as in the plasma C-peptide levels were more marked in the pancreas-kidney-transplanted patients. The findings suggest that the hyperinsulinemia in these patients was due to both the systemic delivery of insulin and an increase in insulin resistance, the latter being particularly apparent in the postprandial phase. In the pancreas-kidney-transplanted patients, elevated plasma glucagon levels were also observed, whereas the mean 24-h level and number of peaks of growth hormone did not differ significantly between the two study groups.
Glucose Homeostasis and Insulin Secretion During Chronic Treatment With Cyclosporin in Nondiabetic Humans
Authors: Robertson R Paul , Franklin Gary , Nelson Lorene
Published: September 2013

Cyclosporin or placebo was administered in a randomized, double-blind fashion to 13 patients with multiple sclerosis for 1 yr to determine whether cyclosporin adversely affects glucose homeostasis or β-cell function. No significant differences were observed in fasting glucose, fasting insulin, intravenous glucose tolerance, or glucose-induced insulin secretion before treatment or at 3 wk, 6 mo, or 1 yr during treatment. Longer therapeutic trials with larger patient groups will be necessary to decide whether cyclosporin can be safely given for many years without risk of developing diabetes mellitus.
Pathogenesis of Diabetic Retinopathy
Authors: Engerman Ronald L
Published: September 2013

Diabetic retinopathy involves anatomic changes in retinal vessels and neuroglia. The pathogenetic mechanism responsible for retinopathy is imperfectly understood, but much of the mechanism is apparently reproduced by experimental diabetes in animals and by chronic elevation of blood galactose in nondiabetic animals. The evidence that retinopathy is a consequence of excessive blood sugars and their sequelae is consistent with a demonstrated inhibition of retinopathy by strict glycemic control in diabetic dogs. However, retinopathy in the dog model has shown a tendency to resist intervention by strict control. Biochemical and pathophysiological sequelae of hyperglycemia possibly critical to the development of retinopathy in humans and animal models are being studied in many laboratories. Retinopathy occurs in experimental galactosemia in the absence of the renal hypertrophy, mesangial expansion, and glomerular obliteration typical of diabetes in humans and dogs, implying that retinopathy and nephropathydiffer appreciably in pathogenesis.
Interaction of β-Cell Activity and IL-1 Concentration and Exposure Time in Isolated Rat Islets of Langerhans
Authors: Palmer Jerry P , Helqvist Steffen , Spinas Giatgen A , Mølvig Jens , Mandrup-Poulsen Thomas , Andersen Henrik U , Nerup Jørn
Published: September 2013

This study was designed to test the hypothesis that target-cell activity influences the degree and time course of interleukin 1β (IL-1β)–mediated β-cellimpairment in vitro. Functional and morphological studies were performed in cultured newborn rat islets of Langerhans exposed from 6 h to 6 days to 50–2000 ng/L recombinant human IL-1β. β-Cell activity was modulated by glucose and nonglucose agents (15 mM L-leucine and 10 μM of long-acting somatostatin analogue SMS 201–995). In 11 mM glucose, 2000 ng/L of IL-1β caused inhibition of insulin release after ∼6 h of exposure to IL-1β; in 3.3 mM glucose culture, onset of inhibition was delayed by this IL-1β concentration until after 48 h of exposure. Similarly, stimulation and suppression of β-cell function with L-leucine and SMS 201–995, respectively, resulted in acceleration and delay of IL-1β-mediated inhibition. The dose-response curve of the IL-1β effect was shifted left- and rightward during high and low β-cell activity, respectively. In analogy, increasing IL-1β concentration, exposure time, and β-cell activity resulted in increasing islet disintegration. Thus, the resting β-cell is more resistant to IL-1β-mediated impairment than the working β-cell.
Prevalence and Risk Factors of Diabetic Retinopathy in Non-Hispanic Whites and Hispanics With NIDDM: San Luis Valley Diabetes Study
Authors: Hamman Richard F , Mayer Elizabeth J , Moo-Young George A , Hildebrandt William , Marshall Julie A , Baxter Judith
Published: September 2013

Diabetic retinopathy (DR) is the leading cause of blindness in adults in the United States. Because photocoagulation can reduce the incidence of blindness from severe DR by ∼50%, it is important to identify people at increased risk for DR so that appropriate treatment can be accomplished. Use of populations at increased risk for diabetes may identify groups at increased risk for complications. A recent report from the San Antonio Heart Study showed that Mexican Americans were at greater risk for servere DR than non-Hispanic Whites. To compare the prevalence of DR between non-Hispanics and Hispanics in southern Colorado, 279 people with non-insulindependent diabetes mellitus (NIDDM) were identified, and retinal photographs identified the presence and severity of retinopathy. The worse eye was used to classify the severity of DR for each patient. Ninety percent of the subjects (166 Hispanics and 85 non-Hispanic Whites) were classified by retinopathy level. The duration-adjusted prevalence of any DR was 41.8% in Hispanics and 54.1% in non-Hispanic Whites. Severe DR (preproliferative and proliferative) occurred in 18.5% of the Hispanics and in 21.3% of the non-Hispanic Whites. The odds ratio for any DR, comparing Hispanics with non-Hispanic Whites adjusted for other risk factors, was 0.40 (95% confidence interval = 0.21, 0.76). Other risk factors for the presence of any retinopathy included use of exogenous insulin, increased duration of diabetes, younger age at diagnosis, increased glycosylated hemoglobin level, and increased systolic blood pressure. These data suggest that, compared with non-Hispanic Whites, Hispanics in Colorado may be at decreased risk for diabetic retinopathy.
Prevalence of Neuropathy in Newly Diagnosed NIDDM and Nondiabetic Control Subjects
Authors: Lehtinen Juha M , Uusitupa Matti , Siitonen Onni , Pyörälä Kalevi
Published: September 2013

We evaluated the prevalence of peripheral neuropathy by clinical and electrophysiological criteria and the prevalence of autonomic parasympathetic nerve dysfunction by heart-rate variation during deep breathing (expiration-to-inspiration ratio [E:I]) in 132 newly diagnosed non-insulin-dependent diabetic (NIDDM) subjects aged 45–64 yr and 142 randomly selected nondiabetic control subjects. The relationship of nerve dysfunction to the degree of hyperglycemia and insulin-secretion capacity were also investigated. Single and scattered symptoms and signs of peripheral neuropathy were found in both diabetic and control subjects. Symptomatic polyneuropathy was found in 1.5% of diabetic subjects but none of the control subjects. Polyneuropathy defined by clinical signs was found in 2.3% of the diabetic subjects and 1.4% of the control subjects. No subjects with both symptoms and signs were seen. Nerve conduction velocities (NCVs) were significantly slower in diabetic than control subjects. Polyneuropathy according to electrophysiological criteria was found in 15.2% of diabetic subjects but was not found in any control subjects. Electromyographic abnormalities were more common in diabetic than control women, but no significant differences were found in men. The resting heart rate was higher in diabetic than control women, but no significant difference was found in men. The mean E:I was significantly lower in diabetic men and women than control men and women. An abnormally low E: I was found in 9.2% of the diabetic men, 3.3% of the control men, 3.3% of the diabetic women, and none of the control women. NCV parameters, but not E:I, were inversely correlated with fasting blood glucose and glycosylated hemoglobin levels. A positive correlation between NCV and fasting and postglucose serum insulin levels was found in both groups. These results show that clinical diabetic neuropathy is not common at diagnosis of NIDDM, but disturbances in peripheral and autonomic nerve function, detected by electrophysiological and cardiovascular reflex methods, are often present at that stage of the disease. The prevalence of neuropathy is also highly dependent on the criteria used. The degree of peripheral nerve dysfunction was associated with the degree of hyperglycemia, but an association between glycemic control and autonomic dysfunction could not be demonstrated.
Hyperproinsulinemia and Amyloid in NIDDM: Clues to Etiology of Islet β-Cell Dysfunction?
Authors: Porte Daniel , Kahn Steven E
Published: September 2013

Impaired islet function is a feature of non-insulin-dependent diabetes mellitus (NIDDM), which is manifested in part by disproportionate proinsulin release. A disproportionate increase in proinsulin also occurs in insulinomas, suggesting that enhanced proinsulin release results from an increase in synthesis and premature release of proinsulin-rich immature granules in both conditions. However, recent human and animal studies suggest that normal β-cells respond to an increase in synthetic demand by enhancing their ability to process proinsulin. Thus, impaired processing of proinsulin is likely in NIDDM. A new point of similarity with insulinoma has been the demonstration of a novel pancreatic peptide isolated from insulinomas and the pancreas of patients with NIDDM. This peptide, named islet amyloid polypeptide or amylin, is also present in normal islets. Because of its association with two apparently dissimilar disease states, we propose a hypothesis that encompasses the observations related to proinsulin and islet amyloid polypeptide and suggest they are manifestations of the same abnormality. In this hypothesis, we suggest that this new pancreatic peptide is a normal participant in the process of proinsulin processing and storage. We also suggest that in the presence of defective proinsulin processing and insulin release, as occurs in NIDDM, hyperglycemie stimulates amylin biosynthesis so that this peptide is deposited in increased quantities in the islet as amyloid. This then further exacerbates the diabetic process, resulting in progressive hyperglycemia and deterioration in islet function.
Distribution of In Vivo Insulin Action in Pima Indians as Mixture of Three Normal Distributions
Authors: Bogardus Clifton , Lillioja Stephen , Nyomba Bulangu Lukuki , Zurlo Francesco , Swinburn Boyd , Puente Antonella Esposito-Del , Knowler William C , Ravussin Eric , Mott David M , Bennett Peter H
Published: September 2013

If a single gene produced insulin resistance, with environmental effects creating some additional variance, insulin action might be distributed as a mixture of two normal distributions if the gene is dominant or recessive or as a mixture of three normal distributions if the gene is codominant. To estimate maximal insulin-stimulated glucose uptake rates (MaxMs), hyperinsulinemic-euglycemic clamps were performed on 245 nondiabetic Pima Indians (126 men, 119 women). Five models (for 1, 2, 3, 4, or 5 components each, normally distributed with a common variance) were fitted to the frequency distribution of MaxM by iterative maximum-likelihood estimation. The three-component model fit the data significantly better than a single normal distribution (χ2 = 14.3 with 4 df P < .01) or a mixture of two normal distributions (χ2 = 9.9 with 2 df, P < .01). Mixtures of four or five normal distributions did not fit the data significantly better than a mixture of three normal distributions. The first component of the distribution comprised 23%, the second 48%, and the third 29% of the total distribution. Similarly, the frequency distributions of fasting plasma insulin concentrations and a principal component score derived from MaxM and fasting insulin were best fitted by a mixture of three normal distributions. These results are consistent with the hypothesis that among Pimas, insulin resistance is determined by a single gene with a codominant mode of inheritance. Segregation analyses of studies performed in pedigrees are indicated to prove or disprove this genetic hypothesis.
Prevention of Nerve Edema and Increased Blood-Nerve Barrier Permeability–Surface Area Product in Galactosemic Rats by Aldose Reductase or Thromboxane Synthetase Inhibitors
Authors: Wadhwani Kishena C , Caspers-Velu Laure E , Murphy Vincent A , Smith Quentin R , Kador Peter F , Rapoport Stanley I
Published: September 2013

Nerve water content and the permeability–surface area product (PA) to [3H]- or [14C]sucrose at the blood-nerve barrier were determined in unanesthetized control rats fed a normal diet and in rats fed galactose with or without an aldose reductase inhibitor (Statil or AL 1576) or a thromboxane synthetase inhibitor (CGS 12970). Nerve water content was determined by taking the difference between dry and wet weights of whole tibial nerves. PA was determined by an intravenous bolus injection of radiotracer with multiple–time-point graphic and quantitative autoradiographic methods. The mean nerve water content in galactosemic rats was 15% higher than in control rats after 7–11 mo on the diet. Statil and AL 1576 prevented nerve edema, but CGS 12970 was only partially effective in preventing an increase in nerve water content in galactose-fed rats. In galactosemic rats, the mean PA to sucrose at the blood-nerve barrier, calculated from nerve dry weight, was twofold higher than in control rats. Treatment with Statil, AL 1576, or CGS 12970 prevented increased PA. Our results suggest that nerve edema and increased blood-nerve barrier PA are secondary to polyol production and can be prevented by inhibiting aldose reductase.
Structure and Function of Insulin Receptors
Authors: Rosen Ora M
Published: September 2013

The actions of insulin are mediated by an integral plasma membrane protein, the insulin receptor. The processed receptor is a tetramer composed of two α-subunits that bind insulin and two β-subunits that traverse the plasma membrane and are, in their cytosolic domains, protein tyrosine kinases. The insulin proreceptor cDNA has been cloned and its complete amino acid sequence deduced. The availability of cDNA permitted an analysis of both the role of protein tyrosine kinase activity in insulin action and the autophosphorylation sites that regulate kinase activity. The human cDNA probe has also been used to identify a putative Drosophila insulin receptor. This work is reviewed, and approaches that may be used to identify physiological substrates for the receptor kinase are suggested.
Erythrocyte Membrane Lipid Peroxidation and Glycosylated Hemoglobin in Diabetes
Authors: Jain Sushil K , McVie Robert , Duett John , Herbst John J
Published: September 2013

Erythrocytes of diabetic patients have abnormal membrane properties. We examined in vivo membrane lipid peroxidation in erythrocytes of diabetic subjects and its possible relationship with hyperglycemia. Lipid peroxidation was assessed in fresh, untreated erythrocytes by quantitating thiobarbituric acid reactivity and an adduct of phospholipids and malonyldialdehyde (MDA), an end product of lipid peroxidation, with thin-layer chromatography of lipid extract of diabetic erythrocytes. There was a significantly increased membrane lipid peroxidation in diabetic erythrocytes compared with nondiabetic erythrocytes. The degree of membrane lipid peroxidative damage in erythrocytes was significantly correlated with the level of glycosylated hemoglobin, an index of mean glucose level for the preceding 3–4mo. This suggests that peroxidation of membrane lipids and accumulation of MDA occurs in erythrocytes of diabetic patients.
Cytoplasmic Retinoid-Binding Proteins and Retinoid Effects on Insulin Release in RINm5F β-Cells
Authors: Chertow Bruce S , Moore Michael R , Blaner William S , Wilford Mark R , Cordle Mary Beth
Published: September 2013

Vitamin A (retinol) is required for insulin secretion, and retinoic acid substitutes for retinol in this function. To determine if retinol acts at the β-cell level, we assayed β-cells of the rat insulinoma (RINm5F) line for cytosolic retinol- and retinoic acid-binding proteins (CRBP and CRABP) by radioimmunoassay (RIA) and [3H]retinol and [3H]retinoic acid binding to cytosol extracts. Furthermore, we tested whether insulin release from cells was affected by addition of retinol or retinoic acid to culture medium. RINm5F cells were grown to near confluence before assay of CRBP and CRABP. Scatchard analysis showed the Kd for retinol to be ∼6 nM at a level of 4.5 pmol/mg protein or 300,000 sites/cell. Sucrose density-gradient assay showed single discrete peaks migrating at 2S for both retinol and retinoic acid. RIA of whole-cell extracts showed CRBP and CRABP levels of 5.27 ± 0.41 and 2.95 ± 0.75 pmol/mg protein, respectively. Retinol (1.75 μM) and retinoic acid (0.175 and 1.75 μM) increased KCI-induced insulin release. Considered together, the presence of CRBP and CRABP in a β-cell line and the increase in KCI-induced insulin release by retinol and retinoic acid are consistent with the idea that retinol has a functional role in insulin secretion and suggest a potential mechanism of action at the β-cell level similar to that observed in other retinoid-responsive cells.
Evaluation of WHO and NDDG Criteria for Impaired Glucose Tolerance: Results From Two National Samples
Authors: Modan Michaela , Harris Maureen I , Halkin Hillel
Published: September 2013

The considerable disagreement in the definition of impaired glucose tolerance (IGT) by National Diabetes Data Group (NDDG) and World Health Organization (WHO) criteria was explored in two independent representative adult population samples in Israel (n = 1119) and the United States (n = 1783). Five categories of nondiabetic glucose tolerance were defined according to fasting plasma glucose (FPG) values (mM) and 1- and 2-h plasma glucose values (PG1 and PG2, respectively) after oral glucose load: 1) normal by WHO and NDDG (FPG <6.4 mM, PG1 <11.1 mM, PG2 <7.8 mM), 2) Normal by WHO, nondiagnostic by NDDG (FPG 6.4–7.7 mM, PG1 <11.1 mM, PG2 <7.8 mM), 3) normal by WHO, nondiagnostic by NDDG (FPG <7.8 mM, PG1 >11.1 mM, PG2 <7.8 mM), 4) IGT by WHO, nondiagnostic by NDDG (FPG <7.8 mM, PG1 <11.1 mM, PG2 7.8–11.0 mM), and 5) IGT by WHO and NDDG (FPG <7.8 mM, PG1 >11.1 mM, PG2 7.8–11.0 mM). Established markers of abnormal glucose tolerance were also measured, including glycosylated hemoglobin A1, insulin response, plasma triglycerides, serum uric acid, and rate of hypertension in Israel as well as rates of hypertension, peripheral vascular involvement, family history of diabetes, and history of cholelithiasis in the U.S. Accounting for potential confounders, levels of these markers in both national samples were similar in categories 1 and 2 and in categories 3–5. Levels were significantly higher in the latter three categories than in the former two. It is therefore recommended that categories 3–5 be considered as constituting IGT. Group 3, with normal PG2 but abnormal PG1, cannot be identified by the WHO oral glucose tolerance test (OGTT), which omits PG1. Therefore, OGTT in studies relating to the nature and associated risks of IGT should include a midtest glucose sample.
Degradation of Insulin and Insulin-Like Growth Factors by Enzyme Purified From Human Erythrocytes: Comparison of Degradation Products Observed With A14- and B26-[125I]monoiodoinsulin
Authors: Misbin Robert I , Almira Ernesto C
Published: September 2013

An insulin-degrading enzyme has been purified from human erythrocytes. This enzyme degraded 125I-labeled insulin-like growth factor I (IGF-I) more slowly than 125I—IGF-II and degraded IGF-II more slowly than 125I-insulin. The time course of 125I-insulin degradation suggested the presence of intermediates, each of which wasitself shown to be a substrate for the enzyme. One of these intermediates appeared to be made up entirely of B-chain residues and had HisB10 as its NH2-terminal. The final major radiolabeled degradation product of A14-[125I]monoiodoinsulin was a peptide with TyrA14 at the A-chain NH2 terminal. This peptide could be reduced with dithiothreitol, suggesting that it contained amino acid residues from both A- and B-chains. It was partially precipitated by trichloroacetic acid and anti-insulin antibody but bound poorly to IM-9 lymphocytes. The final major degradation product of B26-[125I]monoiodoinsulin was a peptide whose NH2-terminal was TyrB26 and could not be reduced by dithiothreitol. It was partially precipitated by anti-insulin antibody but was precipitated poorly, if at all, by trichloroacetic acid and bound poorly to IM-9 lymphocytes. The results show that this enzyme degraded insulin by sequential cleavage of peptide bonds on both A- and B-chains. We identified LeuA13-TyrA14, SerB9-HisB10, and PheB25-TyrB26 as three of the bonds that are cleaved.
Effects of Streptozocin-Induced Diabetes on Glucose Metabolism and Lactate Release by Isolated Fat Cells From Young Lean and Older, Moderately Obese Rats
Authors: Newby F David , Bayo Fernando , Thacker Sheryl V , Sykes Maria , Digirolamo Mario
Published: September 2013

Streptozocin-induced diabetes (STZ-D) was produced in male Wistar rats at two stages of development: young, lean rats, weighing 150–220 g (6–8 wk), and older, moderately obese rats, weighing 450–500 g (6–8 mo). A comparable degree of hyperglycemia (420–500 mg/dl) without ketosis was generated by injection of 50 mg/kg i.v. STZ for young, lean rats and 30 mg/kg i.v. for older, fatter rats. The animals were killed 8–11 days after injection. Insulin binding by the isolated adipocytes of both groups was not significantly altered on a per-cell basis by the presence of diabetes. Total adipocyte glucose metabolism, both basal and insulin stimulated, was reduced (63 and 88%, respectively) by the induction of diabetes in young, lean rats. In contrast, the induction ofdiabetes in the older, moderately obese rats had no suppressive effect on total glucose metabolismby their fat cells. Diabetes increased the relative conversion of glucose to lactate by fat cells from both groups of rats, but in absolute terms, the fat cells from the obese diabetic rats produced significantly more lactate from glucose than cells from the lean diabetic rats, both in the absence and presence of insulin. Diabetes did not alter the glucose concentration at which peak insulin response occurred in either group. We conclude that STZ-D in rats, at different stages of development and degrees of adiposity, results in quantitatively different alterations of adipocyte metabolism, which appear to be postreceptor in nature and result in an increase in glucose conversion to lactate.
Ascorbic Acid Metabolism and Polyol Pathway in Diabetes
Authors: Yue Dennis K , McLennan Susan , Fisher Elizabeth , Heffernan Scott , Capogreco Carmela , Ross Glynis R , Turtle John R
Published: September 2013

It has been reported previously that the plasma concentration of ascorbic acid (AA) is reducedin streptozocin-induced diabetic rats and can be normalized by treatment with the aldose reductase inhibitor tolrestat. This study was designed to investigate further the relationship between the polyol pathway and AA metabolism in diabetic rats. Disturbance of AA metabolism was demonstrable after 1 wk of diabetes. Dietary myo-inositol supplementation was effective in normalizing plasma AA levels, as was treatment with tolrestat. In untreated diabetes, despite low plasma AA concentration, there was increased urinary excretion of AA that was reversed by treatment with either tolrestat or myoinositol. In contrast, AA supplementation normalized plasma AA concentrations while further increasing urinary AA excretion. The abnormality of AA metabolism was less severe in galactose-fed rats, which had normal plasma AA levels and only minor increases in urinary AA excretion. These studies demonstrated a disturbance in the regulation of plasma and urinary AA concentration in experimental diabetes and confirmed the relationship of AA with the polyol pathway. Because AA has many important biological functions, abnormalities of AA metabolism could be important in the pathogenesis of some diabetic complications. The interaction of the polyol and AA pathways suggests that this could be another site of action for aldose reductase inhibitors.
Effects of Dietary Treatment on Serum Insulin and Proinsulin Response in Newly Diagnosed NIDDM
Authors: Yoshioka Narihito , Kuzuya Takeshi , Matsuda Ayako , Iwamoto Yasuhiko
Published: September 2013

Serum proinsulin is disproportionately elevated both in the basal state and after an oral glucose load in non-insulin dependent diabetes mellitus (NIDDM). However, there is no detailed information about the effect of glycemic control on this abnormality. We investigated the effect of glycemic control by dietary treatment on serum proinsulin level in the basal state and in response to an oral glucose load. Ten NIDDM patients (7 men and 3 women), aged 19–60 yr, with mean (± SD) body mass index of 28 ± 6 kg/m2 (range 21–42 kg/m2) and normal renal and liver function were studied. Before and after dietary therapy (25–30 kcal/kg ideal body wt), 100-g oral glucose tolerance tests were performed. Proinsulin was measured with our proinsulin-specific antiserum, which recognizes the connecting site of the B-chain of insulin and C-peptide. After dietary treatment, fasting plasma glucose decreased from 197 ± 35 to 113 ± 18 mg/dl (P < .001). Both serum insulin and proinsulin decreased (insulin from 15 ± 8 to 10 ± 4 μU/ml, P < .02; proinsulin from 31 ± 18 to 13 ± 5 pM, P < .02), and the molar ratio of proinsulin to insulin also tended to decrease (from 0.31 ± 0.08 to 0.24 ± 0.10, P < .10). Insulin response to oral glucose increased after dietary treatment, whereas proinsulin response did not change, resulting in a significant decrease in the molar ratio of the area under the curve of proinsulin to insulin after glucose load (from 0.28 ± 0.12 to 0.13 ± 0.07, P < .001). These results support the concept that glycemic control attained by calorie restriction allows recovery of disproportionate oversecretion of proinsulin in patients with NIDDM, presumably decreasing the demand for insulin secretion from β-cells.
Effects of Diabetes and Diuresis on Contraction and Relaxation Mechanisms in Rat Urinary Bladder
Authors: Kudlacz Elizabeth M , Gerald Michael C , Wallace Lane J
Published: September 2013

Experiments were designed to gain information on the mechanisms leading to diabetic urinary bladder dysfunction. Bladders from control rats, animals subjected to 4–5 wk streptozocin-induced diabetes, and rats subjected to equivalent diuresis produced by 5% sucrose feeding were studied with an in vitro whole-bladder preparation and neurochemical measurements. The diuretic group was used to distinguish alterations produced by metabolic effects on nerve and muscle from those induced by prolonged periods of excessive diuresis. Diuresis alone explains many of the diabetes-induced effects, including decreased norepinephrine levels, postsynaptic supersensitivity for sympathetic regulation of bladder storage, decreased responsiveness to parasympathetic regulation of emptying, and enhanced prostaglandin F2α-induced contraction. Other diabetes-induced effects were not observed in the diuretic controls and are presumed to result from metabolic alterations associated with diabetes. These effects were decreases in norepinephrine uptake and in choline acetyltransferase activity, both markers of nerve terminal function. Thus, diuretic and metabolic factors appear to contribute to the early signs of parasympathetic and sympathetic neuropathy. In contrast, we found no evidence for loss of sensory nerve function in the diabetic bladder, at least at the organ level, because no diabetes- or diuresis-induced changes were observed in responsiveness to substance P or capsaicin.
Sleep-Associated Fall in Glucose Disposal and Hepatic Glucose Output in Normal Humans: Putative Signaling Mechanism Linking Peripheral and Hepatic Events
Authors: clore John N , Nestler John E , Blackard William G
Published: September 2013

Values reported for basal hepatic glucose production and glucose utilization do not reflect metabolic changes occurring during sleep. To determine the effect of sleep with its associated lowered metabolic rate and thermogenesis on glucose kinetics and gluconeogenic substrate availability, 11 normal volunteers underwent an overnight study in which [3-3H]glucose was infused. Despite decreased insulin secretion, a fall in hepatic glucose output was observed with sleep that was synchronous with a reduction in glucose utilization and lipolysis (decreased plasma glycerol and free fatty acids). When activity was increased, these parameters rose toward previously reported basal levels. Prevention of sleep in 6 additional subjects attenuated the fall in glucose utilization and production as well as the fall in glycerol and free fatty acids despite similar insulin and counterregulatory hormone profiles. We suggest that sleep-associated metabolic changes produce a peripheral signal(s) that modulates hepatic glucose production in humans.
Radioassay Determination of Insulin Autoantibodies in NOD Mice: Correlation With Increased Risk of Progression to Overt Diabetes
Authors: Ziegler Anette G , Vardi Pnina , Ricker Alyne T , Hattori Masakazu , Soeldner J Stuart , Eisenbarth George S
Published: September 2013

In an initial cross-sectional study, 29 female and 25 male nondiabetic weaned nonobese diabetic (NOD) mice of various ages (age range 30–300 days, mean 108 ± 10 days) and 11 unweaned NOD pups were evaluated for competitive insulin autoantibodies (CIAAs) with a fluid-phase radioassay. Eleven of 54 (20%) weaned NOD mice had CIAA levels above the range (>39 nU/ml) of 81 control mice. The group of NOD mice that progressed to diabetes had a significantly higher level of CIAAs than NOD mice that did not progress to diabetes (NOD mice progressing to diabetes: CIAA 63 ± 12 nU/ml; NOD mice not progressing to diabetes: CIAA 8 ± 4 nU/ml; P < .02). Seven of 11 (64%) NOD mice having CIAA concentrations exceeding the normal range progressed to diabetes, whereas only 4 of 43 (9%) NOD mice progressed to diabetes without detection of elevated CIAAs (Fisher's exact test, P < .0005). The relative risk of progressing to overt diabetes with CIAA levels >39 nU/ml was therefore 17 (P < .005), giving a positive predictive value of 64%, a negative predictive value of 91%, and an overall accuracy of 85%. None of 11 unweaned NOD pups had CIAA levels above the normal range (mean −9.4 ± 4.9 nU/ml). At 6 wk of age, 37% of female NOD mice were CIAA+, whereas none of the male animals exceeded the normal range at this age (38 ± 13 vs. 5 ± 6 nU/ml, P < .05). Results of testing two samples during the follow-up of NOD mice indicated that individual NOD mice positive or negative for CIAAs generally remain positive or negative, and CIAA concentrations often increased in initially positive animals. Fourteen NOD mice were included in a prospective study, and CIAAs were evaluated at 9-wk intervals over a follow-up of 8 mo. Four of these NOD mice had elevated CIAA levels, and 3 of 4 CIAA+ mice developed overt diabetes, whereas none of the NOD mice with CIAAs <39 nU/ml developed diabetes. These results were consistent with the results of our cross-sectional study. From these data, we concluded that 1) NOD mice express CIAAs to insulin before progressing to overt diabetes, 2) these antibodies appear after weaning, and 3) CIAA analysis can identify animals with increased or decreased risk of progressing to overt diabetes.
Alteration of Phosphoinositide Metabolism, Protein Phosphorylation, and Carbohydrate Levels in Sciatic Nerve From Wistar Fatty Diabetic Rats
Authors: Berti-Mattera Liliana N , Lowery Joan , Day Shawn-Fueng , Peterson Richard G , Eichberg Joseph
Published: September 2013

Sciatic nerve from the Wistar fatty diabetic (FD) rat, a prospective model for non-insulin-dependent diabetes mellitus, was investigated to determine the content of carbohydrates and to measure the incorporation of 32P into phosphoinositides and proteins. This strain has been shown to develop structural abnormalities in nerves and to exhibit reduced conduction velocity. Males became diabetic between the ages of 8 and 10 wk and were maintained together with lean sibling controls until the animals were either 22 or 44 wk old. Throughout this period, FD rats displayed moderate hyperglycemia. The carbohydrate profile of FD rat sciatic nerve exhibited modest increases in glucose, fructose, and sorbitol levels and significantly reduced myo-inositol concentrations, which were comparable at both ages. When nerves from 22-wk-old animals were incubated with [32P]orthophosphate and incorporation of radioactivity into phospholipids was measured, an increase in isotope uptake into phosphatidylinositol-4,5-bisphosphate and phosphatidylinositol-4-phosphate in the distal portions of tissue from the FD rat was observed. This effect was more pronounced in nerves from 44-wk-old rats. Phosphorylation of the major myelin protein P0 was 70% higher in the most distal portion of FD sciatic nerve from 22-wk-old animals. A comparable rise in phosphorylation of P0 as well as the large (P1,) and small (Pr) myelin basic proteins occurred in nerves from 44-wk-old rats. In these animals, an ∼50% decrease in the uptake of 32P into P0 and P, in the most proximal region of FD nerve was also apparent. Thus, peripheral nerve from this genetically diabetic animal model undergoes compositional and metabolic changes that resemble those of the streptozocin-induced diabetic rat. The results suggest that the FD rat could prove useful for future studies of the neuropathic complications of diabetes.
Long-Term Cryogenic Storage of Purified Adult Human Islets of Langerhans
Authors: Kneteman Norman M , Alderson Derek , Scharp David W , Lacy Paul E
Published: September 2013

Reliable high-recovery human islet storage would facilitate tissue matching, organ sharing, and immune manipulation of donor islets and prospective diabetic recipients. Collagenase-isolated, Ficoll-purified pancreatic islets (median 21,000,15% of total islet yield) from eight cadaver pancreases were cultured in vitro for 24 h, equilibrated in three steps with dimethyl sulfoxide (DMSO) to a 2-M concentration, supercooled, nucleated, and cooled at 0.25°C/min to −40°C before storage at −196°C for 44.25 ± 8.75 days. Rewarming at 200°C/min and removal of DMSO with 0.75 M sucrose preceded 48 h of culture and retesting. Recovery postthaw by microscope count on duplicate aliquots was 94.2 ± 3.5% of prefreeze counts and by triplicate assay of extractable insulin was 90.0 ± 22.3% on day 0 and 74.1 ± 12.6% after a 48-h culture. Nonfrozen islets increased basal insulin secretion 7.7 ± 2.8 times after stimulation with 300 mg/dl glucose in perifusion, whereas islets frozen-thawed and cultured 48 h increased 6.2 ± 0.8 times (NS). Peak stimulated insulin release was 0.92 ± 0.14 μU · islet−1 · min−1 before storage and 0.73 ± 0.14 μU · islet−1 · min−1 (79% of control, NS) after freeze-thaw and a 48-h culture. Total insulin secretion (area under curve) was 66% of prefreeze values at 48 h. Immunocytochemical stains revealed preservation of islet morphology postthaw. Electron microscopy showed intact cellular and nuclear membranes and intracellular organelles. Frozen-thawed islets harvested 14 days after renal subcapsular xenografting in nude mice were revascularized and well granulated. Cryopreservation can achieve prolonged storage of large numbers of human islets with high recovery numerically and functionally, making this a feasible approach for future trials of human islet transplantation.
Successful Long-Term Cryopreservation and Transplantation of Human Fetal Pancreas
Authors: Hullett Debra A , Bethke Kevin P , Landry Ann S , Leonard Dann K , Sollinger Hans W
Published: September 2013

To obtain sufficient quantities of human fetal pancreatic tissue (HFP) for transplantation, long-term storage of the tissue must be achieved. The functional viability of HFP after cryopreservation by stepwise addition of dimethyl sulfoxide was determined. Human fetal pancreas explants (1–2 mm3; gestational age 16–21 wk) were prepared and slowly cooled (0.25°C/min) to −40°C before placement in liquid nitrogen. After rapid thaw (37°C) and overnight culture, insulin release in response to high glucose and theophylline challenge determined in vitro functional viability. No difference was found between the responses of fresh and cryopreserved tissue (fresh 29.2 ± 3.0 ng/mg tissue, cryopreserved 29.9 ± 3.3 ng/mg tissue; P > .1). Diabetic BALB/c nu/nu mice transplanted with cryopreserved HFP returned to normoglycemia in 11 ± 2 wk (range 8–15 wk). Oral glucose tolerance tests indicated in vivo serum glucose control equivalent to or better than that of nondiabetic control mice (peak serum glucose of nondiabetic mice 164 ± 66 mg/dl, of cryopreserved grafted mice 180 ± 67 mg/dl; P > .8). In vitro insulin release of cryopreserved grafted tissue demonstrated that the tissue had differentiated and matured and was now capable of responding to high-glucose challenge (39.3 ± 11.5 ng insulin released/mg tissue). The results described herein are the first demonstration that cryopreserved HFP maintains the in vivo capacity to differentiate and mature and the capacity to reverse diabetes in an animal system.
Initial Pathogenic Events in IDDM
Authors: MacLaren Noel , Schatz Desmond , Drash Allan , Grave Gilman
Published: September 2013

A workshop sponsored by the National Institute of Child Health and Human Development was held in June 1988 to discuss the initial events in the pathogenesis of insulin-dependent diabetes and to make recommendations for future studies. Better definition of immunological markers to reliably predict the disease will enable the detection and study of the earliest pathogenic events involved. The precise autoimmune mechanisms and the role of the environment, both in the initiation of the disease process and precipitation of clinically overt disease, need to be accurately determined to define strategies that might eventually lead to its prevention.