bluuebunny/crossref_metadata_2025 huggingface dataset:
Percentage of Carbohydrate and glycemic Response to Breakfast, Lunch, and Dinner in Women With Gestational Diabetes
Authors: Peterson Charles M , Jovanovic-Peterson Lois
Published: September 2013

We studied the relationship between 1-h glucose response and the percentage of carbohydrates in a given meal in 14 gestational diabetic women who did not require insulin therapy and were between 32 and 36 wk gestation. Each subject was > 130% ideal body weight and was placed on a diet of 24 kcal · kg−1 · 24 h−1, with 12.5% of calories at breakfast and 28% of the calories at lunch and again at dinner, with other calorie intake divided among three snacks. Glycemic response was monitored by self-monitoring of blood glucose 1 h after the start of each meal. Ten postprandial values for each meal were averaged for each of the 14 women. The correlation between percentage of carbohydrates and postprandial glucose level at 1 h was strongest for dinner (r = 0.95, P < 0.001), with more variability seen at breakfast (r = 0.75, P = 0.002) and lunch (r = 0.86, P = 0.001). To maintain a 1-h postprandial whole-blood glucose level <7.78 mM required the following percentages of carbohydrates in each meal: 45% at breakfast, 55% at lunch, and 50% at dinner. If 1-h postprandial whole-blood glucose level was to remain <6.67 mM, then the respective values were 33, 45, and 40%. We conclude that the glycemic response to a mixed meal in subjects with gestational diabetes is highly correlated with the percentage of carbohydrates of the ingested meal and varies among individuals and among breakfast, lunch, and dinner. These results emphasize the potential hazard of rote prescription of diets relatively high in carbohydrates during pregnancy complicated by gestational diabetes and the need to validate diet prescriptions with blood glucose monitoring.
Insulin Secretion and Insulin Resistance in Pregnancy and GDM: Implications for Diagnosis and Management
Authors: Kühl Claus
Published: September 2013

Glucose tolerance deteriorates in human pregnancy, but ∼97–98% of all pregnant women retain a normal glucose tolerance, and only 2–3% develop gestational diabetes mellitus (GDM). Both nondiabetic pregnant women and women with GDM exhibit much higher insulin responses to oral or intravenous administration of glucose or amino acids than found in the nonpregnant state, and the insulin responses to a protein-rich meal are also significantly enhanced in pregnancy. Both quantitative and qualitative differences in insulin secretion exist between pregnant women with normal glucose tolerance (NGT) and women with GDM. Insulin responses to oral glucose and protein-rich meals are thus lower in pregnant women with GDM than in women with NGT, despite significantly higher mean plasma glucose concentrations in the women with GDM. Furthermore, peak plasma insulin concentrations occur later in women with GDM than in pregnant control subjects. Finally, a reduced first-phase insulin response to intravenous glucose can be observed in some women with GDM. Impairment of glucose tolerance in pregnancy is not related to a disproportional secretion of proinsulin nor is increased insulin degradation involved. These observations point to pregnancy as a state of peripheral insulin resistance. Because insulin-receptor binding is only slightly changed in pregnancy and not significantly different in pregnant women with NGT and women with GDM, it follows that the insulin resistance is located at the postreceptor level. Insulin-clamp and “minimal model” studies have shown that the whole-body insulin sensitivity is similarly reduced by about two-thirds of nonpregnant values in pregnant women with NGT and women with GDM. The insulin sensitivity is restored postpartum in the pregnant women with NGT and most of the women with GDM, but about one-third of the women with GDM retain a reduced insulin sensitivity. The insulin resistance in pregnancy is predominantly located in the muscle tissue, where a reduced activity of certain key enzymes in glucose and lipid metabolism has been demonstrated. The insulin resistance is compensated by a considerable increase in insulin secretion, and hence most pregnant women are able to retain NGT. However, some women do not have the capacity to increase their insulin secretion to such an extent that the increased peripheral resistance can be overcome; these are the women who develop GDM.
Summary and Recommendations of the Third International Workshop-Conference on Gestational Diabetes Mellitus
Authors: Metzger Boyd E
Published: September 2013

The Third International Workshop-Conference on Gestational Diabetes Mellitus (GDM) was convened in Chicago, Illinois, on 8 November 1990 as an invitational meeting sponsored by the American Diabetes Association with the cooperation of the American College of Obstetricians and Gynecologists, the American Academy of Pediatrics, the National Diabetes Advisory Board, the Centers for Disease Control, and the Diabetic Pregnancy Study Group of the European Association for the Study of Diabetes. The meeting provided a forum for the review of new information concerning GDM in the areas of diagnosis and prevalence, perinatal and long-range implications, and management strategies.
Gestational Diabetes: Can Epidemiology Help?
Authors: Keen Harry
Published: September 2013

Diagnostic criteria for diabetes mellitus (DM) and impaired glucose tolerance from oral glucose tolerance test results in adults are reviewed in the epidemiological context, highlighting the residual differences between World Health Organization (WHO) and National Diabetes Data Group (NDDG) glycemie criteria with respect to the diagnosis of gestational diabetes. Although the value of the diagnosis of DM (WHO/NDDG criteria) in pregnancy is not called into question, attention is drawn to the paucity of evidence linking lesser degrees of glucose intolerance with significant disturbance of pregnancy outcome when confounding variables such as maternal age, adiposity, and parity are allowed for. It is in the area of the detection and treatment of these lesser degrees of glucose intolerance in pregnancy that serious questions of the detriment-to-benefit ratio arise. A population-based multiethnic multicultural inquiry into diagnostic methodology and criteria in pregnancy is proposed, jointly sponsored by the WHO and the International Diabetes Federation, extending, if possible, to a controlled clinical trial of the effects of intervention.
Insulin Sensitivity in Pregnancy
Authors: Cousins Larry
Published: September 2013

Quantitation of insulin sensitivity (S,) with the insulin suppression test, glucose clamp, or the minimal model method has been achieved in various clinical circumstances. The application of these techniques to pregnancy has been limited. It is important to utilize sensitive and reproducible methods to study S, changes in pregnancy to fully understand the normal and pathological metabolic alterations that occur during gestation. These techniques demonstrate that various factors (obesity, body fat distribution, age, dietary manipulation, and exercise) may affect S, measures. The various pregnancy hormones have differential effects on insulin action. There is consensus among the limited in vivo studies in human pregnancy that late gestation is associated with significantly impaired S, compared with the nonpregnant state. Studies with appropriate matching between control and gestational diabetic subjects have failed to demonstrate a significant difference in S, between groups in the third trimester.
Influence of Pregnancy on the 75-g OGTT: A Prospective Multicenter Study
Authors: Lind Thomas , Phillips Peter R
Published: September 2013

This study reports the responses to a 75-g oral glucose tolerance test (OGTT) in 1009 pregnant women from throughout Europe. We reached the following conclusions. 1) A pregnant woman tends to have blood glucose concentrations that are elevated for a longer period of time after an oral glucose load. Therefore, ∼ 10% of women will reach or exceed 8 mM glucose at 2 h, but it is unlikely that 10% of European women have disordered carbohydrate metabolism. 2) The fasting and 1-h values should be included in any analysis of the response of the patient. By doing this, many fewer women will have responses regarded as abnormal; in this series, it reduced the 79 women with a 2-h value >8 mM to 15 who were considered to have carbohydrate intolerance (2 with diabetes, 13 with impaired glucose tolerance [IGT]). 3) By increasing the 2-h cutoff value to >9 mM, the number of women regarded as at risk would be reduced by >50% (from 79 to 32 in this series), but 10 of the 13 women with two abnormal values would still have been detected, as would the 2 diabetic women. 4) From the obstetric viewpoint, mothers who screen positive do not have bigger babies, they deliver close to term, and they do not have particular stigmas such as a family history of diabetes or an increased tendency to smoke or to have an adverse obstetric outcome. However, they do tend to be older and heavier. This raises the question of whether the apparent longer-term consequences such as coronary artery disease and hypertension are not in some measure due to these factors rather than carbohydrate intolerance alone. 5) We recommend that the screening test for disordered carbohydrate tolerance should be based on a 75-g OGTT with at least three blood samples: fasting, 60 min, and 120 min. The fasting value should not exceed 7 mM, the 1-h level should be <11 mM, and the 2-h value should be <9 mM. To diagnose IGT, either the fasting or 1-h concentration should be above the stated values in addition to a 2-h value >9 mM. Diabetes should be diagnosed with the existing World Health Organization criteria. 6) The term gestational diabetes should be reserved for those in whom blood glucose levels are diagnostic of diabetes and not IGT. If the term IGT during pregnancy is too long, the abbreviation gestational IGT is a reasonable alternative.
Is Islet Amyloid Polypeptide a Significant Factor in Pathogenesis or Pathophysiology of Diabetes?
Authors: Steiner Donald F , Ohagi Shinya , Nagamatsu Shinya , Bell Graeme I , Nishi Masahiro
Published: September 2013

Islet amyloid polypeptide (IAPP) or amylin, a recently discovered minor secretory peptide of the β-cell related to calcitonin gene–related peptide (CGRP), is a constituent of amyloid deposits in the islets of many non-insulin-dependent (type II) diabetic individuals and some elderly nondiabetic subjects. IAPP is synthesized as a small precursor at a level of ∼1% that of insulin and is processed, amidated, stored in β-granules, and released along with insulin and C-peptide. Analysis of its gene (located on chromosome 12) supports an evolutionary relationship to calcitonin and CGRP, peptides with which it shares some biological actions. Like CGRP, IAPP antagonizes the action of insulin mainly at the level of muscle glycogen synthesis, but the levels required for this effect seem to be considerably higher than reported circulating levels. No evidence for overproduction of IAPP in diabetic subjects has been found thus far, but much more work is necessary to define its normal secretory rates and clearance. Other proposed actions of IAPP include serum calcium–lowering effects and smooth muscle relaxation; the latter effect might promote the uptake of insulin into the circulation within the islets. Deposition of amyloid is species selective due to structural differences within the central part of the molecule and may be initiated intracellularly in type II diabetes by several mechanisms. No differences in the structure of IAPP or its precursor have been found in individuals with maturity-onset diabetes of the young or type II diabetes. The evidence available at this time does not support the view that IAPP plays a significant role in the insulin resistance of type II diabetes or that deposition of amyloid is a primary event in its pathogenesis. However, further studies of the expression and roles of IAPP may provide new insights into islet molecular biology and physiology.
Content of CoA-Esters in Perifused Rat Islets Stimulated by Glucose and Other Fuels
Authors: Liang Yin , Matschinsky Franz M
Published: September 2013

Fluorometry and high-performance liquid chromatography were used to measure the content of free CoA and the esters of acetate, malonate, succinate, and long-chain fatty acids in isolated perifused rat pancreatic islets exposed to 25 mM glucose or a mixture of fuels (25 mM glucose plus 10 mM glutamine, 10 mM lactate, and 1 mM pyruvate) to assess the role of intermediates of lipid metabolism as candidate metabolic coupling factors in the mechanism of fuel-induced insulin secretion. Insulin secretion was stimulated in a biphasic manner with the fuel mixture, showing twice the potency compared with high glucose alone. Islets perifused for 3 min with high glucose alone or the fuel mixture compared with 2.5 mM glucose showed a significant increase in malonyl-CoA and succinyl-CoA and a decrease in acetyl-CoA. Free CoA and long-chain acyl-CoA levels were unaltered. Perifused islets stimulated with 25 mM glucose for 30 min showed a significant increase in succinyl-CoA and long-chain acyl-CoA and decrease in acetyl-CoA, whereas malonyl-CoA was not affected. However, when islets were stimulated by the fuel mixture for 30 min, malonyl-CoA was maintained at a high level, and the change in succinyl-CoA and long-chain acyl-CoA was similar to that observed in islets stimulated with 25 mM glucose alone. The acetyl-CoA concentration in the islets stimulated with the fuel mixture decreased slightly. These results confirm the viability of the hypothesis that malonyl-CoA and long-chain acyl-CoA serve as metabolic coupling factors in signal transduction when islets are stimulated by high glucose or glucose combined with other fuels.
Changes in Hepatic Glutathione Metabolism in Diabetes
Authors: McLennan Susan V , Heffernan Scott , Wright Lesley , Rae Caroline , Fisher Elizabeth , Yue Dennis K , Turtle John R
Published: September 2013

Glutathione is important in the regulation of the redox state, and a decline in its tissue level has often been considered to be indicative of increased oxidative stress in diabetes. In this study of diabetic rats, the level of hepatic glutathione was normal unless food intake was restricted. Thus, the previous report of a reduction in hepatic glutathione in diabetes is likely to be the result of food deprivation rather than diabetes alone. In contrast to changes characteristic of oxidative stress, the efflux of glutathione in bile from diabetic animals was significantly decreased, whereas hepatic mixed disulfides were unchanged, and the hepatic γ-glutamyltransferase activity was considerably increased. These changes were not reproduced by food deprivation. The decrease in biliary excretion of glutathione in diabetes may reflect an attempt to conserve glutathione by activation of the hepatic γ-glutamyl cycle. We conclude that the disturbances of glutathione metabolism in diabetes are not typical of those seen in oxidative stress or food restriction.
Use of X-Ray Diffraction in Study of Human Diabetic and Aging Collagen
Authors: James Veronica J , Delbridge Leigh , McLennan Susan V , Yue Dennis K
Published: September 2013

Extensive investigations of the solubility and fluorescence of collagen fibers in diabetes have revealed that there are significant changes in their physical properties. These changes are associated with increased cross-link formation. We used X-ray diffraction to study these changes in human extensor tendons at a molecular level in relation to both aging and diabetes. Our results indicate that diabetes induces significant alterations in the ultrastructure of collagen in the lateral packing of the molecules and the axial structure of the specimen. These changes can be induced in normal tendon by incubation in ribose and glucose-6-phosphate but are different from those associated with the normal process of aging.
Implication of Specific DQB1 Alleles in Genetic Susceptibility and Resistance by Identification of IDDM Siblings With Novel HLA-DQB1 Allele and Unusual DR2 and DR1 Haplotypes
Authors: Erlich Henry A , Griffith Robert L , Bugawan Teodorica L , Ziegler Ralph , Alper Chester , Eisenbarth George
Published: September 2013

Genetic susceptibility to insulin-dependent diabetes mellitus (IDDM) is associated with the HLA-DR3 and DR4 haplotypes. The HLA-DR2 haplotype is negatively associated with IDDM, an association that has been interpreted as dominant protection. Here, we describe the molecular analysis of the HLA class II genes in an unusual family with three HLA-DR1/2 siblings, all of whom have IDDM. With polymerase chain reaction amplification and sequence analysis to characterize the class II alleles, we identified a novel DQB1 allele on the DR1 haplotype and an unusual DQB1 allele on the DR2 haplotype. However, the DRB1 alleles on these DR1 and DR2 haplotypes are the conventional alleles (*0101 and *1501, respectively). These results suggest that it is the conventional DQB1 allele (*0602) not the DRB1 allele (*1501) on the protective DR2 haplotype that confers protection in the general population and, furthermore, that these unusual DQB1 alleles may confer susceptibility to IDDM in this family. The unusual DQB1 allele on this DR2 haplotype encodes Asp at position 57, indicating that it is the allele DQB1*0602 and not simply the presence of this residue that is responsible for the protective effect.
Higher Insulin and C-Peptide Concentrations in Hispanic Population at High Risk for NIDDM: San Luis Valley Diabetes Study
Authors: Boyko Edward J , Keane Ellen M , Marshall Julie A , Hamman Richard F
Published: September 2013

Hyperinsulinemia has been demonstrated in Hispanics with normal glucose tolerance and in other populations at higher risk for non-insulin-dependent diabetes mellitus (NIDDM). We compared fasting and glucose-stimulated insulin and C-peptide levels in a community-based sample of 464 Hispanic and 676 non-Hispanic white adult residents of the San Luis Valley of Colorado. All subjects had normal glucose tolerance as confirmed by oral glucose tolerance testing interpreted with World Health Organization criteria. Mean fasting and 1- and 2-h post–glucose load insulin levels were significantly higher in Hispanics versus non-Hispanic whites (fasting 0.08 vs. 0.07 nM, P = 0.0026; 1 h 0.52 vs. 0.47 nM, P = 0.0129; 2 h 0.36 vs. 0.27 nM, P < 0.0001), even after adjustment for age, sex, body mass index, waist-hip ratio, family history of diabetes mellitus, concurrent plasma glucose level, and fasting insulin level. Mean fasting and 1- and 2-h glucose-stimulated C-peptide levels in Hispanics also significantly exceeded those in non-Hispanic whites (fasting 0.58 vs. 0.54 nM, P = 0.0119; 1 h 2.72 vs. 2.46 nM, P < 0.0001; 2 h 2.25 vs. 1.97 nM, P < 0.0001). The C-peptide–insulin molar ratio was greater in non-Hispanic whites than Hispanics at all times measured. These findings confirm that Hispanics with normal glucose tolerance are hyperinsulinemic and that increased insulin secretion is at least partly responsible for this phenomenon. The lower levels of C-peptide compared with insulin in Hispanics suggest that the hyperinsulinemia seen in this ethnic group may be due in part to decreased hepatic insulin extraction.
Exclusive Expression of MHC Class II Proteins on CD45+ Cells in Pancreatic Islets of NOD Mice
Authors: McInerney Marcia F , Rath Satyajit , Janeway Charles A
Published: September 2013

The expression of MHC class II molecules on β-cells of the pancreatic islet has been proposed to play a role in the genesis of insulin-dependent diabetes mellitus in the NOD mouse. We investigated this by immunofluorescent double labeling of islet cells with anti-MHC and anti-CD45 to identify cells of hematopoietic origin. MHC class I expression increased with age on CD45− islet cells. MHC class II expression was not observed on CD45− islet cells at any age; the only cells in the islet that were MHC class II positive were also CD45+. This indicates that all MHC class II–positive cells in the islet are lymphoid cells that infiltrate the islet, whereas the islet endocrine cells express no MHC class II molecules. However, an increase in MHC class I expression occurred on β-cells, and this may play a role in immunopathogenesis.
Specific Association of HLA-DR4 With Increased Prevalence and Level of Insulin Autoantibodies in First-Degree Relatives of Patients With Type I Diabetes
Authors: Ziegler Ralph , Alper Chester A , Awdeh Zuheir L , Castano Luis , Brink Stuart J , Soeldner J Stuart , Jackson Richard A , Eisenbarth George S
Published: September 2013

First-degree relatives of patients with insulin-dependent (type I) diabetes (n = 264 from 106 families) were evaluated with HLA typing and determination of competitive insulin autoantibodies (CIAAs) and islet cell autoantibodies (ICAs). The levels of CIAAs in 30 relatives exceeded our upper limit of normal (≥39 nU/ml), and 30 had high-titer ICAs (≥40 Juvenile Diabetes Foundation units [JDF U]). Eleven of the HLA-typed relatives developed diabetes during follow-up. Twenty-three percent (28 of 123) of the relatives with at least one HLA-DR4 allele were CIAA+ (CIAA ≥39 nU/ml) versus 4% (6 of 141) among DR4− relatives (P < 0.0001). Twenty-one of 22 of the highest CIAA values were all in the DR4+ group (DR4+ vs. DR4−, P = 0.003, Wilcoxon's rank-sum test). HLA-DR3 did not correlate with the level of CIAAs, and neither DR3 nor DR4 correlated with titer of ICAs measured in JDF U. We conclude that, in first-degree relatives of patients with type I diabetes, there is a striking association with HLA-DR4 in both the prevalence of relatives exceeding the normal CIAA range and in the level of CIAAs. These data suggest that a gene on HLA-DR4 haplotypes contributes to the level of anti-insulin autoimmunity, and we hypothesize that DR4-associated diabetes susceptibility, distinct from DR3-associated susceptibility, may be secondary to this influence.
Prevention of Insulitis and Diabetes Onset by Treatment With Complete Freund's Adjuvant in NOD Mice
Authors: McInerney Marcia F , Pek Sumer B , Thomas David W
Published: September 2013

In studies of immune cell defects in autoimmune diabetes mellitus, we observed that complete Freund's adjuvant (CFA) prevented the onset of diabetes when injected into 8- to 10-wk-old prediabetic nonobese diabetic (NOD) mice. The prevalence of the onset of diabetes in the CFA-injected versus uninjected NOD mice was 2 of 81 (2.5%) vs. 231 of 379 (61%) among females and 2 of 44 (4.5%) vs. 83 of 336 (25%) among males, respectively. The incidence of histologically identifiable insulitis was significantly reduced in CFA-treated prediabetic female NOD mice (18%) compared with the incidence in female age-matched controls (70%). Splenocytes or Mac-1+–enriched splenocytes from CFA-treated NOD mice, when cotransferred with splenocytes from diabetic mice, reduced the incidence of diabetes provoked by diabetic splenocytes in vivo. In the spleen, CFA injection induced sustained increases in cell proliferation and an associated major increase in the numbers of an immature cell type that expressed the Mac-1 surface antigen. In CFA-treated NOD mice, lymphocytes derived from the spleen failed to respond in vitro to stimulation by the mitogen concanavalin A or by anti-CD3. When cocultured, Mac-1+ cells, enriched from the splenocytes of CFA-treated mice, suppressed concanavalin A– or anti-CD3–induced proliferation of T lymphocytes derived from either the spleen or thymus of untreated NOD mice. Therefore, treatment with CFA prevents the development of diabetes, and concomitantly, insulitis while stimulating the generation of splenic suppressor cells that are capable of suppressing diabetogenic T-lymphocyte function in vivo and in vitro.
Association of Metformin's Effect to Increase Insulin-Stimulated Glucose Transport With Potentiation of Insulin-Induced Translocation of Glucose Transporters From Intracellular Pool to Plasma Membrane in Rat Adipocytes
Authors: Matthaei Stephen , Hamann Andreas , Klein Harald H , Benecke Heike , Kreymann Georg , Flier Jeffrey S , Greten Heiner
Published: September 2013

To examine the cellular mechanism of the antihyperglycemic action of metformin, we studied its effect on various functional and molecular parameters involved in the pathogenesis of insulin resistance. Isolated rat adipocytes were incubated with or without metformin (1–100 μg/ml) for 2 h at 37°C followed by an incubation with or without insulin (1.72 nM). Metformin treatment had no significant effect on basal 3-O-methylglucose uptake. In contrast, metformin increased insulin-stimulated glucose transport in a dose-dependent manner up to 43 ± 7%. This effect was neither associated with a significant effect of metformin on trace insulin binding (1.74 ± 0.20% without metformin vs. 1.89 ± 0.30% with metformin; P > 0.05) nor with an effect of metformin on insulin-receptor kinase activity as measured by 32P incorporation into the 95,000-Mr β-subunit of the insulin receptor and an exogenous substrate, histone 2B. Determination of glucose-transporter numbers in subcellular membrane fractions, plasma membranes (PMs), and low-density microsomes (LDMs) with cytochalasin B binding revealed that metformin's effect to increase insulin-stimulated glucose transport is associated with a potentiation (38 ± 5%) of insulininduced translocation of glucose transporter from the LDM to the PM, whereas the basal state was not significantly affected (basal LDM 61.3 ± 4.2 vs. basal metformin LDM 63.6 ± 7.1, P < 0.05; basal PM 6.4 ± 2.1 vs. basal metformin PM 7.2 ± 2.8, P > 0.05; insulin LDM 32.7 ± 5.4 vs. insulin-metformin LDM 15.8 ± 3.7, P < 0.01; insulin PM 28.6 ± 4.6 vs. insulin-metformin PM 45.3 ± 4.9 pmol/mg membrane protein, P < 0.01). Immunodetection of glucose-transporter isoforms HepG2 erythrocyte (GLUT1) and muscle adipose tissue (GLUT4) in adipocyte membrane fractions separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and blotted to nitrocellulose revealed that insulin-induced translocation of GLUT1 and GLUT4 is potentiated by metformin. Determination of specific GLUT1 and GLUT4 mRNA levels revealed that this metformin effect is not associated with an increase in glucose-transporter gene expression. We conclude that 1) metformin increases insulinstimulated 3-O-methylglucose transport by potentiating insulin-induced translocation of GLUT1 and GLUT4 glucose transporter from LDM to the PM without affecting glucose-transporter gene expression, and 2) because neither insulin binding nor activation of insulin-receptor kinase in intact cells was significantly altered by metformin, these results suggest that metformin acts at the level of glucose transport.
Transplantation of Purified Islet Cells in Diabetic Rats: III. Immunosuppressive Effect of Cyclosporin
Authors: Pipeleers-Marichal Miriam , Ling Zhi-Dong , Teng Hui , Pipeleers Daniel G
Published: September 2013

This study examined the effect of cyclosporin on the survival of islet β-cell allografts in streptozocin (STZ)-induced diabetic rats. At a daily oral dose of 5 mg/kg, the agent prevented the rejection of isolated islets, provided they were little contaminated by other pancreatic tissue. The immunosuppressive effect rapidly disappeared after discontinuation of the drug, except when the donor tissue had been pretreated to reduce its nonendocrine content. All recipients of cultured and selected islets maintained a normalized state for >15 wk beyond the 5-wk drug course; this was not the case for shorter periods of treatment. A long-term beneficial effect was also observed in all recipients of purified islet β-cell grafts, which reversed without treatment in half of the cases. Cyclosporin markedly reduced the mononuclear cell infiltration in each type of islet β-cell allograft; aggregates of mixed endocrine islet cells were kept virtually infiltration free. Conditions with minimal initial infiltration were associated with long-term graft survival without the need for continuous pharmacological immunosuppression. We conclude that a short-term cyclosporin treatment can induce long-term survival of allografted islet β-cells, provided the grafts are only slightly contaminated by nonendocrine elements. In rodents, sufficient immunosuppression was achieved by circulating cyclosporin levels of 100–400 ng/ml. Higher concentrations were cytotoxic for cultured islet β-cells and islet non–²-cells. A 5-wk treatment with the immunomodulator ciamexone also resulted in long-term survival of purified β-cell allografts but not of cultured islets. These findings indicate that the success of immunosuppressive treatment in islet cell transplantation can be considerably improved by preparing purified cell grafts of well-defined cellular composition.
Release of Amylin From Perfused Rat Pancreas in Response to Glucose, Arginine, β-Hydroxybutyrate, and Gliclazide
Authors: Inoue Kaoru , Hisatomi Akitaka , Umeda Fumio , Nawata Hajime
Published: September 2013

Amylin is a 37–amino acid peptide isolated from the islet amyloid of patients with non-insulin-dependent diabetes mellitus. The isolated perfused normal rat pancreas was used to evaluate the effects of glucose and insulin secretagogues, such as arginine, β-hydroxybutyrate, and gliclazide, on amylin secretion. Glucose and the other stimulants tested elicited a significant release of amylin from the rat pancreas in a biphasic pattern, similar to that of insulin. Dose-response studies of the glucose-induced release of amylin and insulin revealed that they possessed a similar dependency on glucose. However, the release of amylin induced by high concentrations of glucose was partially dissociated from that of insulin; that is, the amylin-insulin molar ratios induced by 22.2 and 33.3 mM glucose (1.11 ± 0.05 and 1.05 ± 0.04%, respectively) were significantly higher than those induced by 16.7 mM glucose (0.90 ± 0.04%, P < 0.01 vs. 22.2 mM glucose, P < 0.05 vs. 33.3 mM glucose). Additionally, when the basal concentration of glucose in the perfusate was increased from 5.6 to 11.1 mM, the response of amylin was unchanged. These data suggest that amylin may be an islet hormone whose abundant response to high concentrations of glucose might contribute to the oversecretion of amylin in the hyperglycemia that accompanies diabetes mellitus.
Inhibition of Diabetes-Associated Complications by Nucleophilic Compounds
Authors: Kumari Kshama , Umar Shahid , Bansal Veena , Sahib Maharaj K
Published: September 2013

Mono- and diaminoguanidine inhibited ambient glucose-induced glycosylated end product formation of albumin and collagen 125I-labeled albumin covalent binding in vitro. Diaminoguanidine was a stronger inhibitor than monoaminoguanidine. These compounds also inhibited rat eye lens aldose reductase activity in vitro noncompetitively with respect to NADPH with Ki = 30.6 mM for monoaminoguanidine and Ki = 12.5 mM for diaminoguanidine. When administered daily for 98 days at a dose of 25 mg/kg body wt i.p., both compounds lowered eye lens sorbitol and aldose reductase activity in normoglycemic and alloxan-induced diabetic rats. Again, diaminoguanidine was a better inhibitor. Daily long-term administration of mono- and diaminoguanidine (25 mg/kg body wt i.p.) inhibited and prevented experimental diabetes–induced lens opacity in rats, respectively. It appears that diaminoguanidine has a better therapeutic potential in controlling diabetic complications.
Prediction and Prevention of IDDM—1991
Authors: Palmer Jerry P , McCulloch David K
Published: September 2013

Although we can now identify some nondiabetic individuals who will subsequently develop clinical insulin-dependent diabetes mellitus (IDDM), our ability to predict subsequent clinical IDDM is far from perfect. In this article, we discuss the status of knowledge regarding the natural history of preclinical IDDM and discuss, especially in relation to predicting IDDM, the genetic, immunologic, and metabolic components of the IDDM disease process.
Antagonistic Effect of Human α-Calcitonin Gene–Related Peptide (8–37) on Regional Hemodynamic Actions of Rat Islet Amyloid Polypeptide in Conscious Long-Evans Rats
Authors: Gardiner Sheila M , Compton Alix M , Kemp Philip A , Bennett Terence , Bose Christopher , Foulkes Ronald , Hughes Bernadette
Published: September 2013

Rat synthetic amidated islet amyloid polypeptide (IAPP) was infused into conscious Long-Evans rats chronically instrumented for the measurement of regional hemodynamics. Rat IAPP (0.25–2.5 nmol · kg−1 · min−1) had dose-dependent tachycardiac and hypotensive effects. Renal blood flow increased at all dose levels in association with incremental rises in renal vascular conductances. Hindquarters blood flow and vascular conductance increased at the higher dose levels, but mesenteric blood flow fell with mean arterial blood pressure (i.e., there was no change in mesenteric vascular conductance). Concurrent infusion of 25 nmol · kg−1 · min−1 human α-calcitonin gene–related peptide (CGRP) (8–37) abolished the hypotensive, tachycardiac, and renal and hindquarters vasodilator effects of rat IAPP, and during administration of both peptides, there was a transient renal and sustained mesenteric vasoconstriction. When the infusion of human α-CGRP (8–37) was stopped, the effects of the continued infusion of rat IAPP were reestablished. The results indicate that the reported ability of IAPP to induce insulin resistance cannot be due to decreased skeletal muscle blood flow. In addition, human α-CGRP (8–37) is an effective antagonist of the hemodynamic actions of rat IAPP. Because it has been shown previously that human α-CGRP (8–37) antagonizes the hemodynamic effects of human α-CGRP, these results, collectively, indicate that human α-CGRP and rat IAPP might act on the same receptor at which human α-CGRP (8–37) is an effective antagonist or that the latter is a nonselective antagonist of separate receptors on which human α-CGRP and rat IAPP act.
Insulin Pulses Less Effective Than Continuous Insulin in Inhibiting PEPCK mRNA Levels Stimulated by cAMP and Dexamethasone in Perifused Hepatoma Cells
Authors: Harrison H Courtenay , Goodner Charles J , Ann Berrie Marry
Published: September 2013

Hepatic glucose production is stimulated in vitro twice as effectively by pulsatile as by continuous glucagon, given equivalent time-averaged doses. Efficacy studies of pulsatile insulin have yielded conflicting results. In the rat hepatoma cell line H-4-II-E-C3, insulin rapidly (t½ 15 min) inhibits transcription of the gene and lowers mRNA levels for the gluconeogenic enzyme. PEPCK via a receptor-mediated process. We attached H-4-II-E-C3 cells to Cytodex-3 μcarriers and used a perifusion column system to test whether pulsatile insulin is more or less effective than equivalent time-averaged doses of continuous insulin. PEPCK transcription was induced by inclusion of cAMP analogue 8-(4-chlorophenyl-thio)-cAMP (0.1 mM) and dexamethasone (0.5 μM) in the perifusion medium. Three columns were exposed either to continuous, pulsatile, or no insulin. After 3 h, total nucleic acid was extracted, and mRNAPEPCK was measured with a sensitive-solution hybridization assay. Continuous insulin inhibited PEPCK expression in a dose-dependent fashion with EC50 1 × 10−11 M. Equivalent time-averaged amounts of insulin delivered as pulses achieved significant inhibition but less effectively than continuous insulin. The apparent EC50 for pulsatile insulin increased from 2 × 10−11 M to 5 × 10−11 M as the oscillatory period was raised from 5 to 20 min, respectively. These observations suggest that insulin-mediated inhibition of PEPCK gene transcription is diminished by a pulsatile mode of administration in marked contrast to the pulse enhancement demonstrated for glucagon-mediated hepatic glucose production.
Reactivity to Human Islets and Fetal Pig Proislets by Peripheral Blood Mononuclear Cells From Subjects With Preclinical and Clinical Insulin-Dependent Diabetes
Authors: Harrison Leonard C , De Aizpurua Henry , Loudovaris Thomas , Campbell Iain L , Cebon Jonathan S , Tait Brian D , Colman Peter G
Published: September 2013

A simple, direct assay for T-lymphocyte reactivity to islet antigen(s) in human insulin-dependent diabetes mellitus (IDDM) should facilitate preclinical diagnosis and the evaluation of intervention therapy to avert autoimmune-mediated β-cell destruction. In subjects with preclinical or clinical IDDM, we measured the reactivity of peripheral blood mononuclear cells (PBMCs) incubated over 6 days with either adult human islets or fetal pig proislets, or other fetal pig tissues, and with human insulin. With islets, the stimulation index (SI) of [3H]thymidine uptake by PBMCs exceeded the mean + 2SD of control subjects in 6 of 6 preclinical subjects (SI 8.7 ± 3.7), 7 of 11 clinical subjects (SI 5.2 ± 3.4), and 1 of 12 control subjects (SI 2.7 ± 1.7); with insulin, the responses were less in frequency and magnitude, being 4 of 6 (2.7 ± 1.6), 3 of 11 (2.2 ± 1.1), and 0 of 12 (1.20 ± 0.55), respectively. The mean responses to islets of PBMCs from preclinical and clinical subjects differed significantly from control subjects (P < 0.02 by 2-tailed Kruskal-Wallis test). Secretion of granulocyte macrophage colony–stimulating factor by PBMCs over 6 days was assayed in the preclinical group and generally paralleled the uptake of [3H]thymidine. PBMC reactivity to islets appeared to be at least as sensitive a marker of preclinical IDDM as autoantibodies to a 64,000-Mr protein, presumably the enzyme glutamic acid decarboxylase, in fetal pig proislets. In conclusion, islet-reactive T lymphocytes in subjects with preclinical and clinical IDDM can be identified in bulk culture of PBMCs. Detection of these autoreactive T lymphocytes should be of value in the diagnosis of preclinical IDDM and in monitoring the effects of immunotherapy.
Streptozocin- and Alloxan-Induced H2O2 Generation and DNA Fragmentation in Pancreatic Islets: H2O2 as Mediator for DNA Fragmentation
Authors: Takasu Nobuyuki , Komiya Ichiro , Asawa Takayuki , Nagasawa Yoshitaka , Yamada Takashi
Published: September 2013

Streptozocin (STZ) and alloxan (ALX) exhibit the most potent diabetogenicity and are used for induction of experimental diabetes mellitus. An understanding of the mechanisms of action of the typical diabetogenic agents is important for elucidating the causes of diabetes. Okamoto proposed a model in which DNA fragmentation plays an important role in the development of diabetes. DNA fragmentation supposedly results from the accumulation of superoxide or hydroxyl radicals. However, direct evidence for this accumulation is lacking. With isolated rat pancreatic islets in vitro, we demonstrated that STZ and ALX stimulated H2O2 generation and caused DNA fragmentation. Addition of STZ or ALX resulted in an increase in H2O2 generation. On DNA analysis, when incubated without STZ or ALX, DNA sedimented as a single peak; when incubated with STZ or ALX, DNA sedimented slower as a broad peak and was fragmented. Graded doses of STZ and ALX stimulated H2O2 generation and induced DNA fragmentation; their effects on H2O2 generation and DNA fragmentation were evident at a concentration of 0.1 mM and were maximal at 1 mM. Administration of STX or ALX to rats in vivo stimulated H2O2 generation and caused DNA fragmentation in pancreatic islets. H2O2 itself also induced DNA fragmentation. These findings may support Okamoto's proposal that STZ and ALX induce diabetes through the following biochemical events: STZ and ALX→H2O2 generation→DNA fragmentation→β-cell destruction. This study may constitute the first demonstration of STZ- and ALX-stimulated H2O2 generation, which probably acts as a mediator of STZ- and ALX-induced DNA fragmentation.
Low-Dose Streptozocin-Induced Autoimmune Diabetes in Islet Transplantation Model
Authors: Weide Lamont G , Lacy Pal E
Published: September 2013

An islet transplant model was used to gain further insight into the immunologic mechanisms involved in low-dose streptozocin (STZ)-induced diabetes. As shown by others, male C57BL/KsJ mice developed diabetes and insulitis after five daily injections of STZ (40 mg · kg−1 · day−1). Syngeneic islet transplants beneath the renal capsule developed insulitis when the islets were transplanted 10–14 days before the daily injections of STZ. In contrast, insulitis of the grafts did not occur when the syngeneic transplants were done 3 days after the five daily injections of STZ. If the donor islets were incubated in vitro with 0.5 mg/ml STZ for 1 h at 37°C and then transplanted after the low-dose STZ administration of the recipients, then a definite insulitis was present in the syngeneic transplants. These findings indicated that this brief exposure to STZ in vitro was sufficient to permit immunologic recognition of the grafts. In vitro STZ-exposed islets transplanted into high-dose STZ-induced diabetic mice also developed insulitis, whereas STZ-exposed islets transplanted into alloxan-induced diabetic mice did not. Donor islets incubated in vitro with STZ and transplanted into unexposed mice did not develop insulitis in the grafts. Thus, preexposure of the recipient to STZ is essential to the development of insulitis within in vitro STZ-exposed islet grafts. This is also specific to islets because in vitro STZ-exposed thyroid tissue transplanted into low-dose STZ recipients failed to exhibit a thyroiditis. These data are consistent with the idea that STZ immunologically alters the β-cell by inducing an antigenic change.
Presence of Insulin Autoantibodies as Regular Feature of Nondiabetic Repertoire of Immunity
Authors: Fineberg S Edwin , Biegel Angenieta A , Durr Kerry L , Hufferd Suzan , Fineberg Naomi S , Anderson James H
Published: September 2013

With an ultrasensitive noncompetitive enzyme-linked immunosorbent assay (ELISA), we tested the hypothesis that the presence of insulin autoantibodies in nondiabetic individuals is a normal event. Plasma and peripheral blood mononuclear cells were obtained from 50 nondiabetic whites for determination of insulin autoantibodies by ELISA and radioimmunoassay (anti-insulin IgG [AI-IgG] and 125I-labeled insulin bound [%]), islet cell antibodies, anti-nuclear antibodies and rheumatoid factor, and HLA class II–type antigens (DR, DRw, and DQ). The range of 125I-insulin binding was significantly < was seen in pretreatment sera from individuals with diabetes (from −0.4 to 0.4% vs. −0.8 to 7.7%, respectively, P = 0.001). Eighty-eight percent of these nondiabetic individuals had significant levels of AI-IgG with preferential binding to human insulin. The geometric mean of AI-IgG concentrations in individuals with significant levels was 180 pM. Binding to human insulin was seen in 88%, to pork insulin in 42%, and to beef insulin in 24% of individuals (P < 0.001 overall; P < 0.05 where more bound to pork than beef insulin). Binding of AI-IgG to human insulin–coated plates was substantially inhibited by preincubation with human insulin (median inhibition 57.6%) with little if any inhibition by glucagon, C-peptide, albumin, or IgG. Four individuals had highly specific human AI-IgG as shown by immunoaffinity studies. AI-IgGs were significantly higher in individuals with the HLA haplotype DR4,DRw53,DQ3 and lower in individuals with DR5,DRw52,DQ1 (P = 0.03 for both). Nondiabetic individuals regularly have elevated levels of human insulin–specific AI-IgG in their plasmas, the magnitude of which may be related to HLA class II–type antigens.
Morphological Analysis of Selective Destruction of Pancreatic β-cells by Cytotoxic T Lymphocytes in NOD Mice
Authors: Hayakawa Michiko , Yokono Koichi , Nagata Masao , Hatamori Nobuo , Ogawa Wataru , Miki Akinori , Mizoguti Humio , Baba Shigeaki
Published: September 2013

Interactions of pancreatic islets and islet-associated mononuclear cells (IAMCs) from the nonobese diabetic (NOD) mouse were morphologically investigated. To obtain IAMCs, pancreatic islets isolated from adult NOD mice were cultured for 7 days with interleukin 2. Noted by light microscopy, interactions between IAMCs and freshly isolated islets from young NOD mice began 30 min after the initiation of the coculture, and 6 h later, normal cellular array of the islets was lost. By electron microscopy, most IAMCs had low nucleus-cytoplasm ratio, the nucleus was notched and exhibited condensed chromatin along the nuclear membrane, and well-developed Golgi complexes and several mitochondria were distributed in the cytoplasm. These IAMCs adhered to β-cells, but not to α- or δ-cells, with their pseudopods and caused cytolysis of β-cells. Immunohistochemical study with antibodies specific for pancreatic hormones demonstrated that only cells reacting with anti-insulin antibody were selectively lost as the incubation time proceeded. Electron immunohistochemistry by immunogold technique showed that effector cells in IAMCs reacted with anti-CD8 (Lyt-2) antibody, but not anti-CD4 (L3T4) or anti-asialogangliosideM1 antibody. In addition, the concentration of pancreatic hormones in the culture medium, used as a marker of cytolysis, also demonstrated that insulin was significantly increased after 6 h of culture, whereas glucagon and somatostatin were not. These results suggest that CD8+ cytotoxic T lymphocytes are involved in the selective destruction of pancreatic β-cells in the NOD mouse.
Psychomotor Slowing Is Associated With Distal Symmetrical Polyneuropathy in Adults With Diabetes Mellitus
Authors: Ryan Christopher M , Williams Theresa M , Orchard Trevor J , Finegold David N
Published: September 2013

To test the hypothesis that diabetes mellitus is associated with cognitive dysfunction, a battery of neuropsychological tests was administered to 75 diabetic adults and an equal number of demographically similar nondiabetic control subjects. Compared with control subjects, diabetic subjects performed significantly more poorly on measures of psychomotor efficiency and spatial information processing. In contrast, no between-group differences appeared on measures of verbal intelligence, learning, memory, problem solving, or simple motor speed. Results from multiple regression analyses showed that clinically significant distal symmetrical polyneuropathy was strongly associated with psychomotor slowing, whereas, glycosylated hemoglobin values were weakly associated with both psychomotor slowing and spatial processing. No other biomedical variables predicted cognitive test performance. These neurobehavioral data are consistent with the hypothesis that a “central neuropathy” may be associated, at least in part, with chronic hyperglycemia.
Effect of Aminoguanidine on Functional and Structural Abnormalities in Peripheral Nerve of STZ-Induced Diabetic Rats
Authors: Yagihashi Soroku , Kamijo Mikiko , Baba Masayuki , Yagihashi Norito , Nagai Kazunori
Published: September 2013

Nonenzymatic glycosylation of structural proteins and the formation of advanced glycosylation end products (AGEs) have been involved in the pathogenesis of diabetic complications. We examined the effect of aminoguanidine, a potent inhibitor of AGE formation, on functional and structural abnormalities in peripheral nerve of streptozocin-induced diabetic rats. Diabetic rats were treated with daily injections of 25 mg/kg body wt s.c. aminoguanidine (AG)-sulfate for 16 wk and compared to untreated diabetic rats. AG treatment improved motor nerve conduction velocity in 12- and 16-wk diabetic rats despite no changes in body weight, blood glucose, and HbAIc levels. AG treatment inhibited an accumulation of fluorescent AGE in diabetic nerves, and morphometric analysis of the sural nerve showed a partial effect on myelinated fiber size and axonal atrophy. These findings suggest that AG may have a beneficial effect on diabetic neuropathy and nonenzymatic glycosylation of peripheral nerve proteins.