bluuebunny/crossref_metadata_2025 huggingface dataset:
Insulin Clearance Contributes to the Variability of Nocturnal Insulin Requirement in Insulin-dependent Diabetes Mellitus
Authors: Dux Shlomo , White Neil H , Skor Donald A , Santiago Julio V
Published: September 2013

We have previously described, in insulin-dependent diabetic subjects (IDDM), a small, but significant, increase in the insulin clearance rate (ICR) during 0600–0800 h as compared with 0100–0300 h. To determine whether this increase was also seen at more physiologic levels of insulin replacement, we calculated ICR during euglycemic clamp studies in 13 patients with IDDM with a constant infusion of insulin at 20 mU/min/ m2 and during insulin replacement from the Biostator GCIIS without exogenous glucose.

During the euglycemic clamp study with constant insulin infusion at 20 mU/min/m2, the ICR was 16% higher at 0600–0800 h than at 0100–0300 h (264 ± 50 ml/min/m2 versus 228 ± 51 ml/min/m2; P < 0.005). During insulin replacement by the Biostator, the mean insulin infusion rate increased by 92 ± 27% (7.5 ±1.1 to 13.5 ±1.2 mU/min/m2; P < 0.001) and ICR increased by 123 ± 30% (130 ± 24 to 268 ± 51 ml/min/m2; P < 0.01) during the prebreakfast period when compared with 0100–0300 h. There was a highly significant correlation (r = 0.97) between the increment in insulin infusion rate and the increment in ICR.

Measurement of insulin concentration in saline solutions, delivered by the Biostator at a same rate and under similar conditions to those in this study, showed that insulin delivery was stable for the 8-h period of this study.

We conclude that, at levels of insulin replacement that maintain blood glucose between 90 and 100 mg/dl, variation in the ICR is an important contributor to the “dawn phenomenon” of increasing early morning blood glucose concentration and insulin requirements in diabetic subjects.
A Murine Model of Insulin-dependent Diabetes Mellitus Resulting from the Cumulative Effects of the Nondiabetogenic Strain of Encephalomyocarditis Virus and a Single Low Dose of Streptozocin
Authors: Blay Roy A , Bigley Nancy J , Giron David J
Published: September 2013

The induction of insulin-dependent diabetes in outbred male and female mice was examined using a combination of the usually nondiabetogenic B-variant of encephalomyocarditis (EMC-B) virus and single low doses of streptozocin (STZ). Neither EMC-B virus nor low doses of STZ were overtly diabetogenic when administered alone; however, when these two insults occurred 1 day apart, diabetes resulted in male but not in female mice. The induction of diabetes was dependent on the time interval between these two insults, since EMC-B virus and STZ given 4 days apart did not induce diabetes. Unexpectedly, when the order of these two insults was reversed, diabetes occurred. The absence of diabetes when EMC-B virus was given before STZ suggested the possibility that virus-induced interferon blocked the cytotoxic effects of STZ. This suggestion was supported by the observation that an antiserum against beta interferon abrogated the virus-mediated protection against STZ-mediated cytotoxicity. Also, Poly I:C administered before a single diabetogenic dose of STZ delayed the onset of severe hyperglycemia.
Increase in Remission Rate in Newly Diagnosed Type I Diabetic Subjects Treated with Azathioprine
Authors: Harrison Leonard C , Colman Peter G , Dean Brian , Baxter Royce , Martin F I R
Published: September 2013

Azathioprine (2 mg/kg) was given, in addition to routine insulin treatment, to alternate patients presenting with recent-onset type I diabetes. Treated (N = 13) and untreated (N = 11) patients did not differ significantly at diagnosis with respect to age, duration of symptoms, body weight, blood glucose, hemoglobin A1c, or presence of ketosis. Eight patients were treated for 12 mo, three elected to stop treatment at 6 mo, and treatment was stopped in two because of side effects. Seven treated patients had a remission compared with one untreated patient. At 12 mo these seven patients were distinguished by significantly higher basal and glucagon-stimulated levels of C-peptide (1.98 ± 0.52 and 3.88 ± 0.34 μg/L, respectively) compared with the other six treated patients (0.93 ± 0.52 and 1.32 ± 0.85 μg/L, respectively), and by the persistence of islet cell cytoplasmic antibodies. Remissions were not sustained in the 1–2 yr after treatment, although relapsed patients required less insulin for control. These results corroborate those from nonrandomized trials using cyclosporine1,2 and suggest that protracted treatment with nonspecific immunosuppressive drugs may be necessary to avert insulin dependence.
Acanthosis nigricans in Obese Women with Hyperandrogenism: Characterization of an Insulin-Resistant State Distinct from the Type A and B Syndromes
Authors: Flier Jeffrey S , Eastman Richard C , Minaker Kenneth L , Matteson Doreen , Rowe John W
Published: September 2013

Acanthosis nigricans and hyperandrogenism are commonly found in patients with extreme target cell resistance to insulin, as in the type A and B syndromes of insulin resistance. However, the significance of concurrent acanthosis nigricans and hyperandrogenism in other clinical settings is not clear. We observed acanthosis nigricans to be present in 5% (15 of 300) of patients being evaluated for hyperandrogenism, and carried out studies of insulin binding and action in a group (7) of these women. Although none were diabetic, all were insulin resistant as assessed by hyperinsulinemia when fasting and after oral glucose administration. All patients were obese (mean IBW, 169%). However, when matched to hyperandrogenized women of similar body weight, patients with acanthosis nigricans were clearly more hyperinsulinemic. Insulin binding to monocytes and red cells was decreased in patients with acanthosis, and the extent of decrease was predicted by the fasting insulin level. There was also marked resistance to exogenous insulin during euglycemic insulin clamp studies in the two patients so tested. Anti-insulin receptor antibodies were not detectable, ruling out the type B syndrome. Unlike the type A syndrome, insulin binding to monocytes of these patients increased after acute (2/2) and chronic (1/1) caloric restriction. In the latter patient, acanthosi nigricans remitted as insulin resistance and the insulin binding defect improved.

We conclude that acanthosis nigricans is present in as many as 5% of women with clinically significant hyperandrogenism. These women, although not diabetic, have fairly marked insulin resistance. Despite a number of clinical similarities to patients with the type A and B syndromes, the insulin resistance of these women seems more likely to be a consequence of their obesity, and caloric restriction would appear to be the most appropriate therapy. The basis for apparent interrelationships between insulin, androgens, and acanthosis nigricans in these and other patients is discussed.
Impaired Somatomedin Generation Test in Children with Insulin-dependent Diabetes Mellitus
Authors: Lanes Roberto , Recker Bridget , Fort Pavel , Lifshitz Fima
Published: September 2013

Recent studies have suggested a partial block in somatomedin (SM) production or growth hormone (GH) action in IDDM. Twelve well-nourished diabetic children (9 males and 3 females with a mean age of 11.2 ± 3.3 yr), six with an HbA1c of 7.9–11.2% (group A) and six with an HbA1c of 12.5–15.6% (group B), were studied as follows: the GH response after 100 μg of oral clonidine and the SM generation capacity after i.m. administration of 0.2 U/kg/dose of human growth hormone (hGH) for 4 days. Group B diabetic subjects had a significantly higher mean ± SD GH increase after clonidine than did group A patients (Δ of 17.4 ± 4.9 versus 5.7 ± 6.0 ng/ml, P < 0.01); the basal GH of both groups were similar (1.6 ± 0.7 versus 2.3 ± 1.4 ng/ml). In contrast, the SM response to hGH was significantly decreased in group B children as compared with those in group A (Δ of 0.3 ± 0.3 versus 1.2 ± 0.4 U/ml, P ± 0.01). The basal SM levels of both groups were normal for age. GH and SM correlated with HbA1c levels (r = +O.80, P < 0.01; r = −0.79, P < 0.01, respectively); there was no correlation with plasma and urine glucose or serum cholesterol, cortisol, and transferrin. Our data indicate a blunted SM response to hGH in group B diabetic subjects; this defect in SM generation is apparently not present in group A subjects. A biologically inactive GH molecule and poor nutrition seem unlikely, but circulating inhibitory factors not picked up by our radioimmunoassay, the degree of diabetes control, or a still unclear metabolic derangement may be contributing to this defect.
Gestational Diabetes: Incidence, Maternal Characteristics, and Perinatal Outcome
Authors: Sepe Stephen J , Connell Frederick A , Geiss Linda S , Teutsch Steven M
Published: September 2013

Accurate estimates of the incidence of abnormal glucose tolerance during pregnancy are virtually nonexistent. Screening select populations of women with risk factors for the condition and the nonrandom, nonpopulation-based nature of most studies have given rise to wide variances in reported incidence. We analyzed data from the states of Mississippi and Washington and from the National Natality and Fetal Mortality Surveys conducted in 1980 in an attempt to provide more accurate population-based estimates of the incidence of gestational diabetes mellitus (GDM). In the national surveys GDM was noted (screening and diagnostic criteria were unavailable) as a complication in 0.38% of all sampled pregnancies; overt (type I and type II) diabetes was noted in 0.78%. Mean maternal age for the GDM group was 28.4 yr; 85% were white (81% controls) and 15% non-white (19% controls). Prepregnancy weights were higher in the GDM group by an average of 20 Ib. However, mean weight gain was less in this group than in controls (23 versus 29 Ib). Perinatal mortality was noted in approximately 2.8% (1.3% in controls) of the offspring in GDM-complicated pregnancies and congenital malformations in 6.4% (7.9% in controls). Methodologic problems were encountered and included lack of screening and diagnostic criteria, underreporting, and underrecording.
Antenatal Screening Using Random Blood Glucose Values
Authors: Lind Tom
Published: September 2013

For many years it has been established practice to test the urine of pregnant women for the presence of glucose in the belief that this is an efficient way to detect diabetes mellitus. It is now becoming recognized that one of the normal maternal physiologic adaptations during pregnancy is an increase in the renal excretion of glucose; on examination, up to 50% of healthy pregnant women will have detectable glycosuria at some stage. As the definition of diabetes mellitus is based on random blood glucose values or the concentrations achieved at defined times after an oral glucose load, it would seem logical that any antenatal screening procedure should be similarly based. A total of 2403 consecutive antenatal patients had a random venous whole blood glucose concentration determined between 28 and 32 wk gestation. Calculated 99% cutoff values were 110 mg/dl (6.1 mmol/L) within 2 h of a meal or 101 mg/dl (5.6 mmol/L) more than 2 h postprandial. Four patients were found to have previously unsuspected but unequivocal diabetes mellitus and four more had impaired glucose tolerance on the basis of the 1980 WHO criteria. Screening all antenatal patients by this method is efficient, does not inconvenience patients, and is relatively cost efficient in terms of staff and laboratory resources.
Effects of Hyperinsulinemia in the Primate Fetus
Authors: Susa John B , Schwartz Robert
Published: September 2013

Nonhuman primate models of gestational diabetes have produced fetopathies most similar to those of the human infant of the mother with gestational diabetes (IGDM). Fetal hyperglycemia, hyperinsulinemia, macrosomia, selective organomegaly, intrauterine death, and placental hyperplasia are hallmarks of the fetopathy of the IGDM. The chronic infusion of insulin into the fetus of a normal pregnant rhesus monkey results in fetal hyperinsulinemia with normal to low plasma metabolic substrate concentrations. Under these conditions, fetal hyperinsulinemia is sufficient to cause fetal growth and hormone changes observed in the human IGDM. Our studies provide evidence that the soft tissue hyperplasia in the fetal macrosomia syndromes in humans and nonhuman primates in which fetal hyperinsulinemia is observed is the direct result of that chronic in utero hyperinsulinemia.
Insulin-like and Insulin-enhancing Effects of the Sulfonylurea Glyburide on Rat Adipose Glycogen Synthase
Authors: Altan Nilgün , Altan V Melih , Mikolay Leona , Larner Joseph , Schwartz Charles F W
Published: September 2013

The effects of long-term exposure of cultured rat adipose tissue to glyburide were examined on glycogen synthase activity. Glyburide alone caused an increase in the activity ratio (low glucose-6-P/high glucose-6-P) of glycogen synthase, and enhanced insulin's activation of the enzyme. The glyburide effects were time dependent, requiring fat pieces to be exposed to the drug for at least 10–20 h. The glucose concentration in the culture medium was also important: optimal concentrations of glucose were 10–20 mM. Glyburide acted to shift the insulin dose-response curve to the left by a factor of 2.5, but did not enhance the effects of maximal concentrations of the hormone. The Ka of the glyburide effects was about 2.0 IAM. If glucose was omitted during the 20-min incubation with or without insulin, the increase in the activity ratio of glycogen synthase by glyburide was unaffected, but the enhancement of insulin action was reduced. Because these data indicate that glyburide's actions are glucose dependent, we propose that the sulfonylurea is probably acting to increase glucose transport, thus allosterically increasing the activity of a synthase phosphatase by glucose-6-P. The net result of this would be increased dephosphorylation and activation of glycogen synthase.
Recruitment, Randomization, and Baseline Characteristics of the Treatment Groups
Authors: Champion Malcolm C , Bending Jeremy J , Rodger N Wilson , Bilous Rudolph W ,   The Kroc Collaborative Study Group
Published: September 2013

The general and ophthalmologic eligibility criteria were applied in the course of formal screening of selected members of clinic populations at the six treatment centers between August 1980 and November 1981. Patients eligible on the grounds of the history and general physical examination underwent a detailed ophthalmologic examination and determination of C-peptide status. Initial rates of recruitment were slow, which occasioned modifications of the eligibility criteria and a prolongation of the recruitment phase. All six clinics approached their goal of at least six patients in each of the continuous subcutaneous insulin infusion (CSII) and conventional insulin treatment (CIT) groups, with a final total of 70 randomized subjects. The method of paired randomization was acceptable, but led to some delay during periods of slow recruitment activity. Data from two patients who chose to drop out of the study shortly after randomization are included in the baseline characteristics. There was no difference between treatment groups with respect to age or duration of known diabetes, body weight, systolic blood pressure, proportion of cigarette smokers, retinopathy level as assigned by analysis of stereofundus photographs, or microaneurysm counts performed on fluorescein angiograms. A trend toward milder retinopathy in the CIT group proved to be statistically insignificant. Subsequent assessment of stereofundus photographs at the Fundus Photograph Reading Center indicated that six patients were misclassified by treatment center ophthalmologists with respect to ophthalmologic eligibility. We conclude that recruitment goals were met and randomization was successful.
Observations on Control of Glycemia with Conventional Insulin Therapy or Continuous Subcutaneous Insulin Infusion
Authors: Tamborlane William V , Champion Malcolm C , Rizza Robert A , Service F John , Bergenstal Richard M ,   The Kroc Collaborative Study Group
Published: September 2013

Determination of glycemic differences between groups treated with continuous subcutaneous insulin infusion (CSII) or conventional insulin therapy (CIT) was central to the major objective of the study. Assessment of glycemia was based on (1) 24-h inhospital profiles of plasma glucose; (2) pre- and postprandial and bedtime (seven time points) diurnal profiles performed monthly on outpatient samples; and (3) glycosylated hemoglobin (HbA1) measured bimonthly at each center. The correlation between plasma glucose determinations in the central laboratory and in local laboratories was 0.988. Significance of differences between treatments was by analysis of variance and least-squares regression.

At baseline, mean inhospital plasma glucose and HbA1, concentrations and insulin dosages were identical in the groups randomized to CSII or CIT. A prompt decrement of indices of glycemic control during CSII was observed such that mean decrements sustained over the 8-mo treatment period in home and in hospital plasma glucose profiles and HbA1 relative to values obtained during CIT (P < 0.0001). The likelihood of CSII-treated patients achieving glycemic indices within the normal range was increased. The standardization of the mean and the M-value calculated from inhospital glucose profiles during CSII and CIT at 4 and 8 mo indicated that there was less plasma glucose fluctuation during CSII.

The method of pooling standardized local HbA1 measurements from the six centers appeared to be an adequate substitute for centrally performed HbA1 determinations. Advantages of inhospital plasma glucose measurements in terms of accuracy and ability to obtain nocturnal samples contrasted with the likelihood of increased realism and superior correlation with HbA1, in home-obtained samples. We have shown in insulin-dependent diabetic patients that prerandomization levels of glycemia were unchanged during CIT, and during CSII a significant decrease in glycemia was established and sustained. The primary aim of the study has thus been achieved.
Origin and Design of the Kroc Collaborative Study
Authors: Champion Malcolm C , Keen Harry , Pickup John C , Tamborlane William V , Dupre John ,   The Kroc Collaborative Study Group
Published: September 2013

Although the benefits of metabolic intervention on the microvascular complications of diabetes mellitus remain unproven, it is generally assumed though not proven that prognosis in terms of blindness and renal failure will reflect the long-term glycemic response to therapy. Treatment goals however remain poorly defined. Costs and hazards of achieving near-normoglycemia in insulin-dependent diabetes mellitus (IDDM) are major. A multicenter trial was proposed to test the hypothesis that in IDDM two levels of mean glycemia, sufficiently separated to examine the control/complications relationship, could be maintained by the six collaborating centers, using randomized patient allocation to conventional insulin therapy (CIT) and continuous subcutaneous insulin infusion (CSII) as the alternative treatment modalities. Methods of maintaining and monitoring metabolic control and of assessing renal and retinal responses were to be applied, evaluated, and possibly improved. All clinics shared a common experimental protocol, which received ethical approval at each treatment center. Retinal assessment facilities were provided by the Fundus Photograph Reading Center at the University of Wisconsin in Madison, and at the Diabetic Retinopathy Department, Royal Postgraduate Medical School, Hammersmith, United Kingdom. The Central Biochemistry Laboratory was at the University of Newcastle, United Kingdom. Collaborators agreed on policy for recruitment, baseline assessment, and randomization of patients with IDDM, complicated by early microvascular disease. CIT took the form of the unchanged prestudy regimen; glycemic goals were set for CSII and their achievement based on inpatient and outpatient sampling of plasma glucose. Glycosylated hemoglobin was measured, retinal abnormalities recorded photographically, and urinary albumin excretion quantitated at baseline, 4, and 8 mo in all patients. As a prelude to the larger multicenter trial required to resolve definitively the question of the costs and benefits of intensified treatment of IDDM, The Kroc Collaborative Study was designed as a test of the feasibility of using currently available methodologies, of meeting the logistic problems of concerted clinical action in multiple centers, and the use of central assessments and of the capacity to sustain the operation for long enough to make a long-term clinical trial of treatment and prevention of the microvascular complications a practical possibility.
Albumin Permeation of New Vessels Is Increased in Diabetic Rats
Authors: Kilzer Paul , Chang Kathy , Marvel Joyce , Rowold Edwin , Jaudes Phyllis , Ullensvang Suzanne , Kilo Charles , Williamson Joseph R
Published: September 2013

125I-bovine serum albumin (BSA) permeation of the vasculature of 3-wk-old granulation tissue (induced by subcutaneous implantation of polyester fabric) formed in the diabetic milieu was assessed in female BB/W, spontaneously diabetic rats and in male, Sprague-Dawley rats with streptozocin-induced diabetes as well as in corresponding nondiabetic controls. Albumin permeation of new granulation tissue vessels was markedly increased in both groups of diabetic animals relative to that of nondiabetic controls, while albumin permeation of vessels in most other tissues did not differ for controls and diabetics. These observations indicate that the functional integrity of new vessels formed in the diabetic milieu is impaired: (1) to a greater extent than that of older vessels formed before induction of diabetes and (2) relative to new vessels in nondiabetics.

The implication of these observations is that molecular constituents of vessels synthesized in the diabetic milieu are quantitatively and/or qualitatively abnormal and/or their incorporation into vessels is defective.
Bone Calcification and Calcium Homeostasis in Rats with Non-insulin-dependent Diabetes Induced by Streptozocin
Authors: Levy Joseph , Teitelbaum Steven L , Gavin James R , Fausto Aurora , Kurose Hirofumi , Avioli Louis V
Published: September 2013

The effect of mild, non-insulin-dependent diabetes (NIDDM) on bone calcification and calcium (Ca) homeostasis was studied in growing rats (males and females). The diabetic state was characterized by mild insulin deficiency, plasma levels being 73% of controls, and mild hyperglycemia, with nonfasting plasma glucose levels of 1.5 times normal. There was no difference in plasma levels of Ca, phosphate (Pi), magnesium (Mg), alkaline phosphatase, immunoreactive parathyroid hormone (iPTH), calcitonin, 25-(OH)vitamin D (25[OH]D), 1,25-dihydroxyvitamin D (1,25[OHrsqb;2D), and 24,25-dihydroxyvitamin D (24,25[OH]2D) between the NIDDM rats and their controls of either sex. Metabolic Ca and Pi balance studies revealed that the experimental animals of both sexes were in positive Ca and Pi balance similar to that of their controls. Histologic studies of the kidney and intestinal slices from the experimental group were normal.

Ca and Pi bone content calculated per gram bone ash of the femur, mandible, and second and fourth caudal vertebrae, and the organic content in the bones of the NIDDM animals showed no difference from their controls. Femur bone density and tibial epiphyseal growth plate width and morphology were similar histologically in the experimental and control rats. No decreased osteoid content in the tibial bone was found in the diabetic rats compared with controls.

Physiologic sex differences, consisting of lower plasma Pi, higher plasma calcitonin levels, increased ratio of femur dry bone weight to total body weight, and increased percentage of mineralized and total bone volume at the tibial metaphysis seen in female compared with male control rats were also seen in the diabetic animals.

The data reveal that, in states of mild insulin deficiency in the rat, the factors that regulate mineral metabolism are functioning normally and bone mineralization proceeds without alterations. In addition, physiologic sex differences are preserved. There is no indication for bone loss under these conditions.
Localization of Saturable CCK Binding Sites in Rat Pancreatic Islets by Light and Electron Microscope Autoradiography
Authors: Sakamoto Choitsu , Goldfine Ira D , Roach Eileen , Williams John A
Published: September 2013

Cholecystokinin (CCK) is a known stimulus for the release of insulin and other islet hormones. To localize islet cell CCK binding sites, we measured the uptake of 125I-CCK by the isolated, perfused rat pancreas. Light microscope autoradiographs revealed uptake of label over both the endocrine islets of Langerhans and the exocrine acini. This uptake of 125I-CCK was saturable, as it decreased markedly when a large excess of unlabeled CCK8 was included in the perfusion solution. To define which cells in the islets bound CCK, electron microscope autoradiographs were prepared. The majority of silver grains in islets were localized over beta cells (69%), although saturable uptake was also observed over alpha (12%) and other islet cells. When grain densities were analyzed (grains/μm2), the highest density was observed over islet blood vessel cells. In contrast to islet blood vessels, there was no localization of 125I-CCK over acinar blood vessels. This study supports the concept, therefore, that there is a direct regulation of islet endocrine cells by CCK, and also raises the possibility that CCK influences islet hormone release via an indirect effect on the islet vascular endothelium.
Lack of Association of the Polymorphic Locus in the 5'-Flanking Region of the Human Insulin Gene and Diabetes in American Blacks
Authors: Elbein Steven , Rotwein Peter , Permutt M Alan , Bell Graeme I , Sanz Nancy , Karam John H
Published: September 2013

A polymorphic region 5' to the human insulin gene has been associated with diabetes in earlier studies. This polymorphic region is composed of tandem repeats that fall into 3 general size classes, designated class 1 (600 base pairs), class 2 (1300 base pairs), and class 3 (2500 base pairs). Frequencies of these classes of alleles vary among racial groups. American Blacks have been underrepresented in published studies of insulin gene polymorphism and diabetes.

We undertook a cooperative study between two centers (San Francisco and St. Louis) to determine genotypes at the insulin locus in 313 unrelated American Blacks (132 nondiabetic, 27 with IDDM, and 154 with NIDDM). In both centers, nondiabetic individuals were younger and leaner than NIDOM patients. Allelic and genotypic frequencies at the insulin locus were not different between the two centers. Class 1 alleles represented 60% of all alleles, class 2 alleles 11%, and class 3 29%. No class of insulin allele was associated with NIDDM in this study. Subdivision of the study population by obesity, family history, or age at diagnosis failed to detect a subgroup for which the insulin allele was associated with NIDDM. Only 27 IDDM individuals were studied, and no significant association of class 1 alleles with this group was noted. However, examination of more IDDM individuals is required before a definitive statement can be made.

Fasting serum triglyceride levels were determined retrospectively in 50 NIDDM individuals. No differences in triglyceride levels among genotypes were noted. The frequency of class 3 alleles in 13 hypertriglyceridemic NIDDM subjects was not different from that of the whole group.

Thus, in American Blacks there is no association of class 3 alleles with NIDDM. Studies using this polymorphic marker in linkage analysis of appropriate families may be more successful in defining a role for the insulin gene in diabetes.
Carbohydrate (CHO) Oxidation in Patients with Type B Insulin Resistance
Authors: Boden Guenther , Shimoyama Ryushi , Savage Richard C , Owen O E
Published: September 2013

Total body carbohydrate (CHO) and fat oxidation rates, plasma glucose, free fatty acid, and insulin concentrations were determined in two patients with the type B syndrome of severe insulin resistance and in normal controls in response to insulin infusions (1–100 mil/kg/min) and to a test meal. In addition, insulin was infused at higher rates (10–1000 mU/kg/min) in one of the two patients while plasma glucose concentrations were clamped first at 195 and later at 244 mg/dl. During the postabsorptive state, resting metabolic rates (RMR) were 914 and 979 cal/min/1.73 m2 in the two patients (controls: 1018 ± 85 cal/min/1.73 m2). Patients met 85% and 83% of their caloric requirements by oxidizing fat (controls: 63 ± 7%). Protein oxidation accounted for 15% and 13% (controls: 14 ± 3%) of energy requirements and CHO oxidation for 0% and 0%, respectively, in both patients (controls: 23 ± 5%). Infusion of insulin at a rate of 10 mU/kg/min raised plasma insulin concentrations from 1400 and 440 nil/ml to 6000 and 2500 (μU/ml, respectively, in patients 1 and 2 (controls: from 4 ± 0.3 to 1288 ± 50 μU/ml), but had no effects on rates of CHO, fat, or protein oxidation in either patient. By comparison, the rate of CHO oxidation in controls rose about sixfold from 40 ± 8 to 234 ± 12 mg/min/1.73 m2. Infusion of 1000 mU/kg/min in combination with an increase in plasma glucose from 195 ± 1.1 to 244 ±1.9 mg/dl in patient 1, however, raised CHO oxidation from 0 to 36 mg/min/1.73 m2 and lowered fat oxidation from 105 to 69 mg/min/1.73 m2. In response to a test meal, rates of CHO oxidation rose from 49 ± 9 to 193 ± 3 mg/min/1.73 m2 in controls, from 24 to 67 mg/min/1.73 m2 in patient 1, and remained 0 mg/min/1.73 m2 in patient 2. We conclude that presence of anti-insulin receptor antibodies (AIRA) suppressed postabsorptive as well as insulin and meal stimulation of CHO oxidation. The depression of CHO oxidation persisted even in the presence of normal or increased rates of glucose disappearance. As a result, patients with AIRA rely predominantly on fat oxidation to meet their normal caloric requirements.
Complement and HLA: Further Definition of High-Risk Haplotypes in Insulin-dependent Diabetes
Authors: Rich S , O'neill G , Dalmasso A P , Nerl C , Barbosa J
Published: September 2013

The families of 41 probands with type I (insulin-dependent) diabetes mellitus (IDDM) were typed for HLAA, HLA-B, and HLA-DR antigens in addition to the complement polymorphisms C2, C4A, C4B, and Bf. All of these loci are encoded on the short arm of human chromosome 6 in a narrow region. Alleles at HLA-B (8, 15, 18, and 40), HLA-DR (3 and 4), and Bf (F1) have been associated with increased relative risk (RR) for IDDM, while HLA-B7 and HLA-DR2 have been associated with decreased RR for IDDM. This study confirms those significant risks in addition to confirming increased risk for the null (silent) allele for C4A (C4AQ0) and a rare C4B variant (C4B2.9). The significantly associated antigens (alleles) and risks were: HLA-B8 (RR = 3.1), HLA-DR3 (RR = 5.2), HLA-DR4 (RR = 4.3), and BfF1 (RR = 7.1), in addition to C4AQ0 (RR = 2.8) and C4B2.9 (RR = 12.6). Significantly low risk was associated only with HLA-DR2 (RR = 0.1).

In a recent study, we defined five high-risk haplotypes that were determined solely by HLA-B, Bf, and HLA-DR (B8-BfS-DR3, B8-BfS-DR4, B15-BfS-DR4, B18-BfF1-DR3, and B40-BfS-DR4). By inclusion of information from the complement polymorphism, we have defined in greater detail three of these five high-risk haplotypes. One previously identified haplotype (B40-BfS-DR4) showed no complement clustering, while the rare high-risk haplotype (B8-BfS-DR4) was seen only once in this smaller sample. Information at the HLA-A locus was deemed important only in the definition of the B8-BfS-DR3 extended high-risk haplotype. Three haplotypes that exhibited significantly increased risks with complement inclusion were B8-BfS-C2C-C4AQ0-C4B1-DR3 (RR = 2.4), B15-BfS-C2C-C4A3-C4B2.9-DR4 (RR = 10.2), and B18-BfF1-C2C-C4A3-C4BQ0-DR3 (RR = 10.6). Of possibly major significance, it was shown that all probands carried at least one high-risk antigen or allele.
Plasma, Adrenal, and Heart Catecholamines in Physically Trained Normal and Diabetic Rats
Authors: Jobidon Christiane , Nadeau André , Tancrède Gilles , Nguyen Minh-Hau , Rousseau-Migneron Suzanne
Published: September 2013

This study was designed to evaluate the possibility that the enhanced insulin sensitivity of physically trained normal and diabetic rats is due to adaptive changes in the adrenergicsystem. Mild diabetes mellitus was induced in male Wistar rats with streptozocin (STZ, 45 mg/kg i.v.) and a 10-wk conditioning program was conducted by having the animals run on a treadmill.Rats were cannulated 16 h after the last period of exercise and blood sampling was obtained 48 h later for basal plasma glucose, insulin, epinephrine, and norepinephrine determination. Catecholamine measurements were also made in adrenals, atria, and ventricles from sedentary control, trained control, sedentary diabetic, and trained diabetic rats. The previously reported beneficial effect of physical training on diabetes mellitus was reproduced. While diabetes mellitus did not modify the catecholamine levels, the training program provoked an increase in plasma epinephrine concentrations, with a concomitant significant rise in adrenal epinephrine content. In heart tissue,the epinephrine values also tended to be increased by training although statistical significance was not reached. These data suggest that basal secretion of epinephrine is somewhat increased in trained rats. Whether this may trigger adaptive changes that could be involved in the beneficial effect of physical training on experimental diabetes mellitus remains to be elucidated.
Effect of the Estrogen Antagonist, Tamoxifen, on Development of Glomerulosclerosis in the Cohen Diabetic Rat
Authors: Cohen A M , Rosenmann E
Published: September 2013

Long-term administration of the estrogen antagonist,tamoxifen, to female, Cohen diabetic rats caused a significant decrease in the incidence of glomerulosclerosis, 12.5% as compared with 58.3% in control, untreated, diabetic female rats. This change in incidence was correlated with a corresponding decrease in plasma estradiol and cholesterol levels, but not with changes in oral glucose tolerance or insulin response. A similar correlation between decreased incidence of glomerulosclerosis and a decrease in plasma estradiol was previously noted in ovariectomized animals.
Effect of Diabetes on Triiodothyronine and Reverse Triiodothyronine Production in the Perfused Rat Liver and Kidney
Authors: Ikeda Tadasu , Ito Yasuo , Murakami Isao , Mokuda Osamu , Kuno Satoru , Tokumori Yutaka , Tominaga Masato , Mashiba Hiroto
Published: September 2013

This study was undertaken to elucidate the effect of diabetes on the conversion of T4 to T3 and rT3 in the isolated, perfused rat liver and kidney. The livers and kidneys from streptozocin (STZ)-induced (50 mg/kg i.p. 2 wk before killing) diabetic rats with or without T4 (30 μg/kg s.c. daily) treatment were perfused for 30 min with a synthetic medium containing T4 (6 μg/dl), and production of T3 and rT3 in the tissues was measured by radioimmunoassay.

The production of T3 (111 ± 38 ng/g/30 min, mean ± SD) and conversion rate of T4 to T3 (19.7 ± 5.8%) in the liver of diabetic rats without T4 treatment and those (124 ± 41 ng/g/30 min and 21.6 ± 4.9%) in the liver of diabetic rats with T4 treatment were significantly lower than those of controls (196 ± 48 ng/g/30 min and 30.6 ± 5.2%), respectively. The production of rT3 and conversion rate of T4 to rT3 in the liver of diabetic rats with or without T4 treatment were similar to those of controls.

The production of T3 and rT3, and conversion rate of T4 to T3 and T4 to rT3, in the kidney of diabetic rats with or without T4 treatment were not significantly different from those of controls.

These results suggest that the liver is far more important than the kidney in the overall reduction in the T4 to T3 conversion that occurs in diabetic rats.
Elevated In Vivo Insulin Clearance in Pima Indians with Non-insulin-dependent Diabetes Mellitus
Authors: Vasquez Barbara , Reaven Gerald M , John W
Published: September 2013

In vivo insulin clearance in 10 subjects with non-insulin-dependent diabetes mellitus (NIDDM) has been compared with clearance in eight equally obese nondiabetic control subjects by two different methods. The first approach consisted of determining the metabolic clearance rates of exogenously infused insulin (MCR,) during hyperins Ulinemic (100 mU/m2 min) glucose clamp studies. The results indicated that mean (± SEM) MCR, was 1.4-fold greater in the diabetic subjects (436 ± 22 ml m2 min) than in the controls (325 ± 24 ml/m2min, P < 0.005), resulting in a lower steady-state plasma insulin concentration in the diabetic (255 ± 8 μU/ml) compared with the nondiabetic subjects (329 ± 29 μU/ ml, P < 0.001). The impact of NIDDM on insulin removal rates was also estimated by a second method in which extraction of endogenously secreted insulin (EXT1) in response to an oral glucose load was calculated from the integrated area above basal of plasma insulin (∫IRI) and of plasma C-peptide (∫CPR), an estimate of β-cell secretion. The results demonstrated that fractional extraction of endogenously secreted insulin (EXT1 = 100 [{∫CPR - ∫IRI}/∫CPR]) was also 1.2-fold greater for diabetic subjects (88.9 ± 2.5%) than for nondiabetic controls (72.0 ± 2.8%, P < 0.001). Finally, these two independent measurements of in vivo insulin removal rates (MCR, and EXT1) were significantly correlated with each other (r = 0.71, P < 0.002). These observations are consistent with the view that elevated insulin clearance may contribute to the postchallenge hypoinsulinemia of NIDDM in Pima Indians.
Sorbinil Prevents Diabetes-induced Increases in Vascular Permeability But Does Not Alter Collagen Cross-Linking
Authors: Williamson Joseph R , Chang Katherine , Rowold Edwin , Marvel Joyce , Tomlinson Martha , Sherman William R , Ackermann Karen E , Kilo C
Published: September 2013

In recent studies we have demonstrated a marked increase in albumin permeation of new vessels formed by angiogenesis (in subcutaneous tissue) in the diabetic milieu. Likewise, lysyl oxidase-mediated collagen cross-linking is markedly increased in the scar tissue associated with angiogenesis. The present studies were undertaken to determine whether sorbinil, a chemical inhibitor of aldose reductase that has been shown to prevent and reverse diabetic cataracts and neuropathy, also could prevent the vascular permeability and collagen cross-linking changes in this model. Vascular permeation by 125I-BSA, collagen cross-linking, and tissue levels of sorbitol, myo-inositol, and scyllo-inositol were assessed in male Sprague-Dawley rats 3 wk after injection of streptozocin and induction of angiogenesis and collagen synthesis in polyester fabric implanted subcutaneously.

Sorbinil (∼25 mg/kg/day) added to the diet of diabetic rats reduced the diabetes-induced increases in albumin permeation by 80%, completely prevented diabetes-induced changes in tissue levels of sorbitol and myo-inositol, and markedly reduced diabetes-induced changes in tissue levels of scyllo-inositol. In contrast, sorbinil had no effect on plasma glucose levels or collagen solubility (an index of collagen cross-linking). These observations indicate that increased vascular permeability associated with diabetes is linked to imbalancesin sorbitol/inositol metabolism. These findings also indicate that (1) diabetes-induced increases in vascular permeability and in collagen cross-linking are independent phenomena and (2) diabetes-induced increases in vascular permeability are largely preventable by treatment with an aldose reductase inhibitor in the face of high plasma glucose levels.
Low pH and Ketoacids Induce Insulin Receptor Binding and Postbinding Alterations in Cultured 3T3 Adipocytes
Authors: Putten J P M Van , Wieringa Tj , Krans H M J
Published: September 2013

The etiology of insulin resistance during diabetic ketoacidosis is still poorly understood. Changes in insulin receptor binding and the existence of postreceptor alterations have been proposed. In an attempt to clarify the role of low pH and ketone bodies in the insulin resistance, we examined the effectiveness of insulin during and after 48 h of exposure of cultured 3T3-L1 adipocytes to low pH and ketoacids. In the “acute” stage, lowering of physiologic pH (pH 7.4) to pH 6.9 induced a decrease in insulin binding (50%), which was due to a decrease in the rate of association. Concomitantly, the insulin sensitivity was decreased (ninefold). The basal hexose uptake and insulin responsiveness were only slightly decreased at low pH. Beta-hydroxybutyrate partially counteracted the effect of low pH on insulin binding and sensitivity in a dose-dependent fashion (ED50: 10 mM). The binding-enhancing effect of ketoacids was more pronounced at low pH than at physiologic pH and absent at optimum pH (pH 8.0). After 48 h of exposure of the cells to pH 6.9, insulin binding and insulin sensitivity (measured at physiologic pH) were similar as in cells cultured at pH 7.4. The insulin response, however, was substantially impaired (40%), due to an increase in basal hexose uptake as well as a decrease in maximal insulin-stimulated uptake. These postbinding alterations induced by low pH could be reversed by culturing the cells at physiologic pH for another 48 h. Prolonged exposure to ketoacids did not affect the insulin effectiveness. Our data suggest that the insulin resistance accompanying ketoacidosis is due to low pH-induced insulin receptor binding as well as postbinding alterations. Ketoacids do not seem to contribute to the insulin resistance.
Comparison of Insulin-mediated and Glucose-mediated Glucose Disposal in Patients with Insulin-dependent Diabetes Mellitus and in Nondiabetic Subjects
Authors: Hansen I L , Cryer P E , Rizza R A
Published: September 2013

To determine whether glucose-mediated as well as insulin-mediated regulation of glucose utilization and glucose production is impaired in patients with insulindependent diabetes mellitus (IDDM), six nonobese, diabetic patients and seven age-, sex-, and weightmatched nondiabetic subjects were studied. Despite slightly higher free insulin concentrations in the diabetic patients than in the nondiabetic subjects during 0.2 mU/kg · min (22 ± 3 versus 15 ± 2 μU'ml) and 1.0 mU'kg · min (98 ± 10 versus 75 μU/ml) insulin infusions, glucose utilization at plasma glucose concentrations of 95, 135, and 175 mg/dl was lower in the diabetic patients than in the nondiabetic subjects. The increment in glucose utilization per increment in plasma glucose (i.e., slope) in the diabetic and nondiabetic subjects, respectively, did not differ significantly during either the 0.2 (1.7 ±1.3 versus 1.4 ± 0.5 dl/kg · min) or 1.0 (4.4 ±1.1 versus 6.2 ±1.0 dl/kg · min) mU/kg · min insulin infusions, although they tended to be higher in the nondiabetic subjects during the latter infusion.

Thus, although stimulation of glucose utilization by insulin is impaired in patients with IDDM, the ability of an increase in glucose concentration to increase glucose utilization does not appear to differ from that present in nondiabetic subjects, at insulin concentrations in the low physiologic range. Whether differences exist in the high physiologic range remains to be determined.
Glucose-stimulated DNA Replication of the Pancreatic Islets During the Development of the Rat Fetus: Effects of Nutrients, Growth Hormone, and Triiodothyronine
Authors: Swenne Ingemar
Published: September 2013

DNA replication and insulin release have been studied in islets isolated, using a tissue culture technique, from rat fetuses of different gestational ages. The islets were cultured for 3 days in media with high and low concentrations of glucose or amino acids. The DNA replication was determined by autoradiography and the insulin secreted into the medium was measured by radioimmunoassay. In islets of 22-day-old fetuses, DNA replication was stimulated by both glucose and amino acids. At gestational days 18 and 20, only amino acids increased DNA replication. However, both high glucose and high amino acid concentrations increased the islet insulin secretion into the culture medium at all ages studied.

In an attempt to induce glucose-sensitive DNA replication in vitro, islets obtained from 18- and 20-day-old fetal pancreata were cultured in the presence of either triiodothyronine or human growth hormone. Triiodothyronine failed to influence either DNA replication or insulin release. Growth hormone, however, increased DNA replication and insulin release in both the experimental groups but did not induce a growth response to glucose.

It is concluded that the appearance of glucose-stimulated B-cell growth is a late event in the fetal development of the rat, parallelling the late maturation of both insulin biosynthesis and release. This finding may explain the difficulties in producing islet cell hyperplasia and diabetic fetopathy previously shown in rat models of diabetes in pregnancy.
Fibrinopeptide-A in Diabetes Mellitus: Relation to Levels of Blood Glucose, Fibrinogen Disappearance, and Hemodynamic Changes
Authors: Jones Robert L
Published: September 2013

Plasma and urine fibrinopeptide-A (FPA) levels were investigated in type I and II diabetic patients. Plasma FPA and 24-h urinary excretion of FPA were significantly elevated in diabetic patients compared with normal volunteers, indicating augmented thrombin activity in diabetes. Plasma and urine FPA did not differ between type I and type II diabetic subjects. Comparison ofplasma FPA with blood glucose and hemoglobin A1 (HbA,) indicated that elevation of FPAis rapidly reversible and intermittent during hypo- and hyperglycemia. Although elevated plasma FPA was seen in patients of short as well as long duration of diabetes, plasma and urine FPA correlated with duration of diabetes in type I patients.

In type I diabetic patients with vascular complications, hyperglycemia induced by an oral glucose challenge was accompanied by elevation of plasma FPA and acceleration of fibrinogen disappearance. These responses were not seen when the patients were treated with intravenous (i.v.) heparin before the glucose challenge. In patients without vascular complications, there was also an acceleration of fibrinogen disappearance and a marginal (not statistically significant) elevation of plasma FPA seen after the FPA response observed in vascular disease patients. In all patients, induced hyperglycemia resulted in a decrease in hematocrit and hemoglobin (blood volume expansion) and an increase in pulse pressure indicating hemodynamic changes. The association of hyperglycemia and hemodynamic changes with augmented thrombin activity is consistent with a mechanism for fibrin formation and deposition based on endothelial injury and/or increased vascular permeability. Fibrin deposition due to such a mechanism may participate in the development of the vascular complications of diabetes.
Virus-induced Diabetes Mellitus: No Evidence for Immune Mechanisms in the Destruction of β-Cells by the D-Variant of Encephalomyocarditis Virus
Authors: Yoon Ji-Won , McClintock Patrick R , Bachurski Cindy J , Longstreth Janice D , Notkins Abner Louis
Published: September 2013

A possible contribution of the immune system to the pathogenesis of virus-induced diabetes mellitus was investigated using the D-variant of encephalomyocarditis (EMC-D) virus. Studies on the F1 and backcross progeny of susceptible and resistant strains of mice gave no suggestion of a linkage between susceptibility and the major histocompatibility locus. Immunosuppression by antilymphocyte serum did not prevent the induction of EMC-D-induced diabetes. Athymic nude mice infected with EMC-D virus showed a nearly identical diabetogenic response as comparedwith heterozygous litter mates. Passive transfer of lymphocytes from mice made diabetic with EMC-D virus into normal mice failed to produce diabetes. From these and other studies, we conclude that the development of EMC-Dinduced diabetes is due to the direct destruction of β-cells by the virus and that the contribution of the immune response to the pathogenesis of this disease is, at the most, minor.