bluuebunny/crossref_metadata_2025 huggingface dataset:
New Polymorphisms at the Insulin Locus Increase Its Usefulness as a Genetic Marker
Authors: Elbein Steven C , Corsetti Lynn , Permutt M Alan
Published: September 2013

Polymorphic sites adjacent to known genes can be used to examine the segregation of a disease relative to that gene in families, or to map the gene of interest relative to other loci. The polymorphic region 5' to the human insulin gene (5' FP) permits such analysis, but the three size classes previously identified are insufficient for many studies. More alleles are identified with restriction enzymes that generate small fragments (Pvu II). Nonetheless, sufficient polymorphism for informative family analyses is often not present.

To facilitate such analyses, we searched for other polymorphisms in over 20 KB of DNA at the insulin locus in Pima Indians, American Blacks, and Caucasians. The previously described allelic variant at a Pst I site in the 3'-untranslated portion of the gene was not polymorphic in any race. An upstream Hinc II site (−62 BP) was present in only 48% of Black alleles, but was not polymorphic in Pima Indians or Caucasians. New polymorphisms were found at a Taq I site (−11,000 BP) and a Rsa I site (−13,000 BP). The Taq I site was present in 89% of Black alleles, 87% of Pima Indian alleles, and 84% of Caucasian alleles. In contrast, the Rsa I site was present in 60% of Black and Caucasian alleles, but in only 47% of Pima Indian alleles. The Hinc II, Rsa I, and Taq I sites show no obvious linkage with each other or the 5' FP.

A fourth polymorphism, previously identified with Sac I, was found to be the creation of a new Sac I site at +2500 BP in 10% of Black alleles. This site was present only in linkage with the presence of a Hinc II site and certain sizes of the 5' FP, and only in Blacks. The usefulness of the new polymorphisms in the 5' FP (Pvu II digest) results in an increase in the number of matings that would be informative for linkage of this locus with a disease from 70% to 93%. Thus, the addition of these markers to the 5' FP permits informative linkage analysis in almost all families.
Activation of Aldose Reductase from Human Tissues
Authors: Das Ballabh , Srivastava Satish K
Published: September 2013

Human aorta, brain, and muscle aldose reductase, partially purified by DEAE-cellulose (DE-52) column chromatography, is activated 2–2.5-fold on incubation with 10 μM each of glucose-6-phosphate, NADPH, and glucose for 20 min at 25°C. The activation of the enzyme was established by following the NADPH oxidation as well as the sorbitol formation using glucose as substrate. The activated form of aldose reductase exhibited monophasic kinetics with glucose and glyceraldehyde, whereas the unactivated or native enzyme exhibited a biphasic kinetics with both the substrates. The activated enzyme was less susceptible to inhibition by aldose reductase inhibitors such as sorbinil, alrestatin, and quercetrin as compared with the unactivated enzyme. Similarly, the native enzyme was strongly inhibited by some of the phosphorylated intermediates of glycolytic pathway, such as 3-phosphoglycerate, 1,3-diphosphoglycerate, 2,3-diphosphoglycerate, and ADP,whereas the activated enzyme was either not inhibited or inhibition was 20–30% only. Partially purified aldose reductase from the normal human lens exhibited properties similar to the native enzyme of other tissues, whereas the enzyme from clear lens obtained from diabetic subjects with severe hyperglycemia expressed properties similar to the in vitro activated enzyme of aorta, brain, and muscle.
Influence of Fasting and Refeeding on the Antilipolytic Effect of Insulin in Human Fat Cells Obtained from Obese Subjects
Authors: Engfeldt Peter , Bolinder Jan , Östman Jan , Arner Peter
Published: September 2013

The antilipolytic effect of insulin was investigated in obese subjects before and after 7 days of total fasting, and 1 h after oral refeeding with 100 g glucose. Isolated fat cells were prepared from subcutaneous gluteal adipose tissue and incubated in vitro. Specific insulin receptor binding and insulin inhibition of basal and isoprenaline-stimulated lipolysis were determined. During the fasting period, a 15% increase (P < 0.05) in high-affinity insulin binding and a concomitant 3–4-fold increase in insulin sensitivity were noted, and there was a marked enhancement of the maximum insulin-induced inhibition of basal lipolysis, from 4 to 10 μmolof glycerol/107 cells/2 h. The maximum insulin-induced inhibition of isoprenaline-induced lipolysis was similar before and after fasting, about 10 μmol/107 cells/2 h. Glucose refeeding induced a 30% decrease (P < 0.02) in high-affinity insulin binding and a 20–60-fold decrease (P < 0.01) in the sensitivity of the antilipolytic effect of insulin under basal conditions and in the presence of isoprenaline. The maximum antilipolytic effect of insulin, however, was not altered by glucose refeeding. Thus, in the basal state, maximum antilipolytic effect was larger after refeeding as compared with that before fasting. The high-affinity insulin binding and insulin sensitivity were significantly lower after refeeding than before fasting. Before the fasting period, neither the insulin binding nor the antilipolytic effect ofthe hormone was altered by oral glucose. It is concluded that fasting and glucose refeeding are associated with marked alterations in the antilipolytic effect of insulin on human fat cells of obese subjects. Antilipolysis is enhanced during fasting due to a combination of receptor and postreceptor alterations of insulin action. Glucose refeeding induces an acute state of insulin resistance (within 1 h) due to a decrease in insulin receptor binding and insulin sensitivity without achange in antilipolysis at the intracellular level. Insulin inhibition of basal and catecholamine-stimulated lipolysis is influenced in different ways by fasting and refeeding.
Coma at the Onset of Young Insulin-dependent Diabetes in Japan: The Results of a Nationwide Survey
Authors:   Japan and Pittsburgh Childhood Diabetes Research Groups
Published: September 2013

The descriptive epidemiology of diabetic coma at onset was investigated in a nationwide survey of insulin-dependent cdiabetic(IDDM) children (age at onset <18 yr) throughout Japan for the years 1970–81. Of the 1172 cases, 148 (12.6%) were unconscious at onset. Diabetic coma was highly associated with abnormalities in the biochemical variables. There was no sex difference in the frequency of coma; however, there was an inverse association with age wherein children under 5 yr of age were approximately two times more likely to present in coma than older children. There was a strong association with reported infections wherein patients with coma were more than twice as likely to report infection than patients without coma. It seemed that the frequency of coma did not decline during the study period. The risk of dying at onset was very high; diabetic children in coma (4.7%) were 12 times more likely to die than patients without coma.
Gestational Diabetes Mellitus: Correlations Between the Phenotypic and Genotypic Characteristics of the Mother and Abnormal Glucose Tolerance During the First Year Postpartum
Authors: Metzger Boyd E , Bybee David E , Freinkel Norbert , Phelps Richard L , Radvany Ruta M , Vaisrub Naomi
Published: September 2013

We evaluated glucose tolerance during the first year postpartum in 113 women with gestational diabetes mellitus (GDM) diagnosed according to the criteria of the First International Workshop-Conference on GDM and the National Diabetes Data Group. The high incidence of abnormal postpartum glucose tolerance (38% “diabetes mellitus” plus 19% “impaired glucose tolerance”) was correlated with certain of the heterogeneous characteristics of the population at the time of antepartum diagnosis. Virtually all women with antepartum fasting plasma glucose (FPG) >130 mg/dl (GDM class BO remained abnormal postpartum (21/22 [95%]), which suggests that this group may include women with preexisting glucose intolerance unrecognized before pregnancy. In the remainder, those with FPG > 105–129 mg/dl (GDM class A2) were more likely to be abnormal postpartum than those with FPG <105 mg/dl (GDM class A,). Within the A, and A2 groups, increasing maternal age, relative insulinopenia, and hyperglycemia at 2 h during antepartum OGTT were also associated with a greater likelihood of abnormal glucose tolerance postpartum. The presence of HLA-DR3 and/or -DR4 antigens was not predictive of the status of glucose tolerance during the first year postpartum, although the increased frequency of cytoplasmic islet cell antibodies in A2 and B1 subjects was associated with a high incidence of abnormal postpartum glucoregulation.

The high incidence of abnormal postpartum glucose tolerance in all GDM classes makes a compelling case for careful, early, and continuing follow-up of all women with a diagnosis of GDM. The risks of abnormal glucose tolerance in the first year postpartum appear to be correlated with some of the heterogeneous characteristics of women with GDM. Differences in such genotypic and phenotypic features as we have analyzed may account for differences in the incidence of postpartum abnormality in different populations. They must be considered in all studies attempting to elucidate the pathophysiology of GDM or to evaluate therapeutic strategies designed to alter the prognosis for glucoregulation under nongravid conditions.
Screening for Gestational Diabetes: Optimum Timing and Criteria for Retesting
Authors: Jovanovic Lois , Peterson Charles M
Published: September 2013

Because of the morbidity associated with undiagnosed gestational diabetes (GDM), screening programs are advocated in all pregnancy clinics. The purpose of this study was to elucidate the optimum time to test for diabetes during gestation, the indication for retesting, and the predictive value of a positive screening test for a large (>4000 g) infant. Women (N = 300) were screened at three time points: 9–20 wk, 27–31 wk, and 33–36 wk. An additional group of 300 women were screened at two time points: 27–31 wk and 33–36 wk. The prevalence of GDM in this group was 3.2%. The optimum timing for screening for highest yield was 27–31 wk. Retesting at 33–36 wk appeared cost effective if (1) maternal age was ≥33 yr, (2) a positive screen was present at 27–31 wk, and (3) the mother was obese (>120% ideal body wt).
The Possibility of an Early Growth Delay in White's Class A Diabetic Pregnancy
Authors: Pedersen Jan Fog , Mølsted-Pedersen Lars
Published: September 2013

Ultrasound scanning has revealed that some fetuses of women with insulin-dependent diabetes are smaller than normal in early pregnancy as judged by the crown-rump length. This early growth delay is negatively correlated to the quality of diabetes regulation. Nine White's Class A diabetic women had fetuses that were on average 4.5 days (range, 0–11 days) smaller than expected from the menstrual history. Apparently, the expectedly modest metabolic disturbances in early pregnancy of Class A diabetic women are able to interfere with normal embryonic growth.
Relationships of Infant Birth Size to Maternal Lipoproteins, Apoproteins, Fuels, Hormones, Clinical Chemistries, and Body Weight at 36 Weeks Gestation
Authors: Knopp Robert H , Bergelin Robert O , Wahl Patricia W , Walden Carolyn E
Published: September 2013

It has been hypothesized that plasma triglyceride fatty acids may traverse the placenta and contribute to infant adiposity particularly in GDM pregnancy. It has also been hypothesized that high-density lipoproteins (HDL) can both deliver cholesterol to and remove cholesterol from the placenta. To determine if these maternal parameters are related to fetal growth in normal pregnancy, we have examined relationships of lipoprotein lipids, apoproteins, hormones, fuels, clinical chemistries, and maternal weight at 36 wk gestation to infant birth weight, birth weight ratio (birth weight corrected for gestational age), birth length, and head circumference in a cohort of pregnant women attending a prepaid health plan, Group Health Cooperative of Puget Sound. Associations were examined using a multivariate regression analysis of several groups of related variables. Results show that the birth weight and/or birth weight ratio are weakly positively associated with maternal very-low-density lipoprotein (VLDL) triglyceride and statistically significantly positively associated with apoprotein A-I, placental lactogen, estradiol, bilirubin, and maternal prepregnancy weight and pregnancy weight gain. Glucose and insulin predict birth weight only in pairwise analysis. Significant negative predictors of birth weight or birth weight ratio include VLDL cholesterol, apoprotein A-II, SGOT, and creatinine. Significant positive predictors of birth length include apoproteins A-I, placental lactogen, and maternal weight. Apoprotein A-II negatively predicts birth length. Only maternal prepregnancy weight predicts head circumference. The results are compatible with the hypothesis that triglyceride fatty acids cross the placenta and contribute to fetal adiposity in normal pregnancy and that the process can be exaggerated in the hypertriglyceridemic GDM woman. The positive association of apoprotein A-I and the strong negative association of apoprotein A-II with birth weight and length point to a physiologically significant role for HDL subfractions in fetal growth, possibly relating to the provision of cholesterol for placental steroid hormone synthesis and fetal cellular proliferation.
The Effect of Diet and Insulin on Metabolic Profiles of Women with Gestational Diabetes Mellitus
Authors: Maresh M , Gillmer M D G , Beard R W , Alderson C S , Bloxham B A , Elkeles R S
Published: September 2013

Twenty women with abnormal glucose tolerance, detected from a routine program of antenatal screening for gestational diabetes mellitus (GDM) at 28 wk, were admitted for 24-h metabolic profiles. They were then alternately allocated to either insulin and dietary restriction or dietary restriction alone and then retested 4 wk later while on therapy. Ten normal controls were assessed twice at similar gestations to the study group. Before treatment, the 20 gestational diabetic subjects had higher mean concentrations of plasma glucose and 3-hydroxybutyrate than the controls for most of the profile, but mean insulin values were similar.

Insulin therapy was associated with a reduction in mean glucose concentrations so that the profile was similar to the controls, while in the diet-alone group the reduction was less. The 3-hydroxybutyrate concentrations rose between profiles in the normal group and also rose in those treated by diet alone, but still remained within the upper range of normal even at night. Insulin therapy resulted in a similar 3-hydroxybutyrate profile to the controls. The C-peptide response to breakfast was reduced in both groups to levels below that of the controls.

Neonatal outcome indices were similar in the two treatment groups, despite the differences in maternal metabolites, but because of the size of this study, conclusions about the neonate must be tentative.
Nonenzymatic Glycosylation of Erythrocytic Proteins in Normal and Diabetic Subjects: Enzymes of Nucleoside and Nucleotide Metabolism
Authors: Agarwal K C , Parks R E , Widness J A , Schwartz R
Published: September 2013

A modification of the technique of Glyco-Gel affinity column chromatography has been employed to separate glycosylated proteins from nonglycosylated proteins of hemolysates. When glycosylation in hemolysates of 11 type I diabetic subjects was compared with that from 7 normal subjects, significant increases were found in glycosylation of hemoglobin (Hb) (12.1 ± 6.0% versus 4.7 ± 0.5%) and purine nucleoside phosphorylase (PNP) (5.3 ± 3.0% versus 2.1 ± 0.5%). However, no differences were found for nucleoside diphosphokinase (NDPK) (1.5 ± 1.1% versus 1.0 ± 0.4%) and adenylate kinase (AMPK) (0.5 ± 0.4% versus 0.7 ± 0.2%). Linear relationships were seen between glycosylated Hb and glycosylated PNP (r = 0.97) or glycosylated NDPK (r = 0.81). On incubation of hemolysates from normal individuals with high glucose (1500 mg/dl or 83 mM) and NaCNBH3 (20 mM), linear increases in the degrees of glycosylation were seen with time. After 18 h, the percentages of glycosylation of Hb, PNP, NDPK, and AMPK were increased from normal values to 31, 24, 11, and 3, respectively. When partially purified human erythrocytic PNP was incubated with various monosaccharides (20 mM) in the presence of NaCNBH3 for 6 h, glycosylation increases of 2–5-fold were seen in the order ribose > mannose > galactose > glucose.
Islet β-Cell Function and Polymorphism in the 5′-Flanking Region of the Human Insulin Gene
Authors: Permutt M Alan , Rotwein Peter , Andreone Teresa , Ward W Kenneth , Porte Danil
Published: September 2013

The present study investigates the possible relationship between human β-cell secretory capacity and polymorphism in the 5′-flanking region of the human insulin gene. The glucose potentiation slope was measured in normal and non-insulin-dependent diabetic subjects (NIDDM). This slope, as reported previously (Ward, W. K., et al., Am. J. Physiol. 1984; 246:E405–11), is an index of the ability of hyperglycemia to potentiate the insulin response to arginine and as such is a measure of β-cell responsiveness to glucose. Restriction enzyme analysis using a human insulin gene probe was performed on leukocyte DNA isolated from the same individuals. We conclude that a 1.6 kb polymorphism in the 5′-flanking region of the human insulin gene in both normal and NIDDM subjects has no association with insulin secretory responses as defined here by the glucose potentiation Slope.
Meal-stimulated C-Peptide and Insulin Antibodies in Type I Diabetic Subjects and Their Nondiabetic Siblings Characterized by HLA-DR Antigens
Authors: Hoogwerf Byron J , Rich Stephen S , Barbosa Jose J
Published: September 2013

We studied serum C-peptide (CP) response 90 min after a breakfast meal and insulin antibody titers in 171 type I diabetic (IDDM) patients and 272 of their nondiabetic siblings from 169 unrelated families. HLA typing was performed in all participants.

In IDDM patients, there was a decline in CP response with increased duration of disease. CP responses of >1.8 ng/ml were seen significantly less often in patients who were <10 yr old at the time of diagnosis of IDDM than in patients who were >10 yr old at the time of diagnosis (8% versus 21%, P < 0.05). More patients with HLA-DR4 had a CP response >1.8 ng/ml than did patients who lacked this antigen whether duration of IDDM was <10 yr (30% versus 18%, P > 0.05) or >10 yr (15% versus 0%, P < 0.05). Mean C-peptide was also higher in HLA-DR4-positive patients compared with HLA-DR4-negative patients both when duration of disease was <10 yr (1.7 ±1.9 versus 1.4 ± 1.0, P < 0.01) and >10 yr (1.2 ± 1.5 versus 1.0 ± 0.4, P < 0.0001). Insulin antibody binding was slightly higher in patients with HLA-DR4 compared with patients lacking this antigen (5.96 ± 7.20 versus 4.89 ± 4.74, P < 0.001).

The nondiabetic male sibs had higher postprandial plasma glucose (PG) (84 ± 22 versus 79 ± 20, P < 0.05) and lower serum CP values (3.8 ±1.6 versus 4.2 ± 1.7, P < 0.05) than did female sibs. There were no differences in mean PG or CP values in sib groups characterized by HLA-DR type or HLA haploidentity with IDDM probands.

In conclusion, pathogenetic heterogeneity of IDDM is supported here by the following: (1) patients with earlier onset of IDDM seem to have more severe beta cell insult, and (2) DR4-positive patients give evidence of better preservation of beta cell function, even in the earlier onset classes.
Urinary Excretion of Plasma Proteins in Diabetic Subjects: Increased Excretion of Kappa Light Chains in Diabetic Patients With and Without Proliferative Retinopathy
Authors: Teppo Anna-Maija , Groop Leif
Published: September 2013

The urinary excretion of β2-microglobulin, albumin, kappa light chains, transferrin, and IgG as well as their concentration ratios were assessed in 27 nondiabetic patients with proteinuria and in 72 IDDM patients, 41 with proliferative retinopathy (PR) and 31 without retinopathy, matched for age, duration of diabetes, and treatment. The mean excretions of albumin, transferrin, and IgG were similar in patients with nondiabetic proteinuria and in IDDM patients with PR and were significantly higher than in IDDM patients without retinopathy. Despite similar albumin excretion, the amount of excreted kappa light chains was significantly higher in IDDM patients than in patients with nondiabetic proteinuria, resulting in an elevated kappa chain/albumin ratio. Furthermore, diabetic subjects without microalbuminuria showed increased kappa chain/albumin ratio, indicating that increased urinary excretion of kappa chains may be an early sign of diabetic nephropathy. Determination of kappa light chain excretion may have clinical implications in the differentiation between proteinuria of diabetic and nondiabetic origin. The ratio kappa chain/albumin was independent of the excretion of β2-microglobulin in patients with PR, suggesting that the reduced ability to reabsorb immunoglobulin light chains may occur earlier than that of β2-microglobulin in the development of tubular dysfunction in insulin-dependent diabetes mellitus.
Effect of Low-Dose Somatostatin Infusion on Pancreatic and Gastric Endocrine Function in Lean and Obese Nondiabetic Human Subjects
Authors: Schusdziarra V , Lawecki J , Ditschuneit H H , Lukas B , Maier V , Pfeiffer E F
Published: September 2013

The present study was designed to compare, in lean and obese nondiabetic subjects, basal and postprandial levels of peripheral venous plasma insulin, glucagon, gastrin, pancreatic polypeptide (PP), glucose, triglycerides, and somatostatin-like immunoreactivity (SLI) during the infusion of synthetic somatostatin-14 or saline. Thirty-five minutes before the ingestion of the test meal, an infusion of synthetic somatostatin-14 was started at a rate of 0.5 ng/kg · min and was increased to 1.0 ng/kg min 30 min after consumption of the meal and lasted foranother 90 min. During the infusion of saline, basal peripheral vein levels of insulin, gastrin,and triglycerides were elevated in obese subjects, whereas basal plasma SLI levels were significantly lower compared with the lean controls. Basal glucagon and PP levels were similar in both groups. After the ingestion of the meal, augmented concentrations of insulin and gastrin were observed in the obese subjects, whereas postprandial SLI and PP levels were reduced. Chromatography of fasting plasma revealed all measurable SLI to be confined to the void volume fractions of a Bio-Gel P-10 column. The rise in SLI after the meal was due to an increase of SLI coeluting with somatostatin-28 and somatostatin-14. During the infusion of somatostatin, only basal insulin levels were significantly lower in the obese subjects, whereas no change of any basal hormone level was observed in the lean group. During the infusion of somatostatin, SLI levels were elevated by 20–30 pg/ml in both groups compared with the saline controls. During the infusion rate of 0.5 ng/ kg · min, only postprandial PP levels were reduced significantly in the obese group, while all the other parameters were unaffected in both groups. At 1.0 ng/ kg · min, postprandial plasma insulin, PP, and gastrin levels were reduced significantly in the obese group,anda transient decrease of glucagon was observed in both groups in comparison with the respective saline control experiments. These data demonstrate an augmented inhibitory effect of intravenously infused synthetic somatostatin on basal and postprandial insulin and postprandial gastrin and PP release in obese subjects. This increased responsiveness to somatostatin suggests that reduced postprandial immunoreactive SLI levels in the obese group might represent true biologically relevant hyposomatostatinemia, facilitating the hypersecretion of some but certainly not all gastric and pancreatic endocrine factors in obesity.
Comparison of Portal and Peripheral Insulin Delivery on Lipid Metabolism in Streptozocin-diabetic Rats
Authors: Kruszynska Y T , Home P D , Alberti K G M M
Published: September 2013

Severely diabetic (150 mg/kg streptozocin, STZ) rats were transplanted with fetal pancreatic islets: (1) under the renal capsule to model peripheral insulin delivery, and (2) into the splenic pulp to model portal delivery. In both groups of transplanted animals, weight gainand blood glucose levels were normal as were peripheral plasma insulin levels. Plasma nonesterified fatty acids, glycerol, acetoacetate, 3-hydroxybutyrate, triglyceride, and cholesterol levels were normal in the two groups of transplanted animals as were VLDL-triglyceride turnover and totalketone body turnover. Adipose tissue lipoprotein lipase activity was also normal in both the fed and fasting states. The findings indicate that consistent normoglycemia and normalization of manyaspects of lipid metabolism can be achieved in the rat with peripheral insulin delivery without associated hyperinsulinemia.
Maturation of Fetal Rat Lung in Diabetic Pregnancies of Graduated Severity
Authors: Bourbon J R , Pignol B , Marin L , Rieutort M , Tordet C
Published: September 2013

Biochemical and morphologic maturation of fetal rat lung was studied in pregnant, diabetic rats with different levels of glucose intolerance (sub-, mildly, and severely diabetic). Fetuses were almost normoglycemic and hyperinsulinemic in subdiabetic rats, both hyperglycemic and hyperinsulinemic in mildly diabetic rats, and hyperglycemic but hypoinsulinemic in severely diabetic rats. A similar delay in type II pneumocyte differentiation and a similar decrease of disaturated phosphatidylcholine (DSPC) content in lung tissue and broncho-alveolar material recovered by lung lavage occurred in the fetuses of the three diabetic groups, independently of the severity of diabetes. Phosphatidylglycerol (PG) was decreased in fetuses from severely diabetic rats only. DSPC appeared specifically affected in fetuses of sub- and mildly diabetic groups, whereas in those of severely diabetic groups, DSPC alterations accompanied a variety of abnormalities including whole lung hypoplasia and hypotrophy and decreases of sphingomyelin, unsaturated PC, and lysoPC. The mechanisms leading to abnormal lung development could therefore be different in fetuses of sub- and mildly diabetic rats on one hand and fetuses of severely diabetic rats on the other. Since hyperinsulinemia was the prominent feature of fetal “milieu interieur” in subdiabetic rats, this study presents arguments gained from in vivo experiments for an implication of hyperinsulinemia in lung developmental retardation due to maternal diabetes. However, the decrease of PG seems to depend on increased blood glucose level in itself. Diminished lung giycogen breakdown and decreased lung triglyceride content, more pronounced in fetuses of sub- and mildly diabetic rats than in those of severely diabetic rats, suggest that in the former, the decrease of DSPC biosynthesis could be due to decreased availability of substrates because of abnormal giycogen utilization.

Fetuses from sub- and mildly diabetic rats constitute experimental models most closely resembling the human fetus of the diabetic mother with respect to circulating glucose and insulin. They appear therefore more adequate for elucidating the mechanisms of abnormal lung development in the diabetic pregnancy. In contrast, fetuses from severely diabetic rats associate very high blood glucose levels and hypoinsulinemia, which are features closer to those of adult diabetic subjects than to those of the human fetus of the diabetic mother.
Recognition of Human Insulin and Proinsulin by Monoclonal Antibodies
Authors: Storch Max-Jürgen , Petersen Karl-Georg , Licht Thomas , Kerp Lothar
Published: September 2013

High-affinity monoclonal antibodies (MAB) were obtained from lymph node cell fusions. Affinities ranging from 0.8 × 109 L/M to 5.2 ×109 L/M were calculated from binding studies with monoiodinated human, bovine, and porcine insulins and human proinsulin.

Two monoclonal antibodies were specific for human insulin, recognizing an epitope involving the amino acid B-30 (Thr). Another two monoclonal antibodies were bound to the C-terminal end of the B-chain near B-30.

The B-chain-specific monoclonal antibodies did not bind human proinsulin. One monoclonal antibody recognized the A-chain loop in the positions A-8 to A-10. This antibody bound also to human proinsulin. It was concluded that the A-chain loop is exposed on the surfaceof proinsulin, while the C-terminal B-chain is not available for binding.

The study shows that monoclonal antibodies can be used to characterize structures of insulin and proinsulin. In contrast to x-ray studies, the molecules can be used at low concentrations in soluble form. It is suggested to use monoclonal antibodies for the screening of atypical insulins in the serum of diabetic patients and for the further refinement of insulin and proinsulin measurements.
Human Insulin Receptor Gene: Data Supporting Assignment to Chromosome 19
Authors: Straus Daniel S , Pang Kenneth J , Kull Frederick C , Jacobs Steven , Mohandas T
Published: September 2013

Somatic cell hybrid clones constructed by crossing human skin fibroblasts with mouse L cells have been examined for expression of human insulin receptors, using a monoclonal antibody directed against the human insulin receptor. Data obtained in this study support the assignment of the human gene for the insulin receptor to Chromosome 19.
Plasma Pancreatic Polypeptide Response to Insulin-induced Hypoglycemia as a Marker for Defective Glucose Counterregulation in Insulin-dependent Diabetes Mellitus
Authors: White Neil H , Gingerich Ronald L , Levandoski Lucy A , Cryer Philip E , Santiago Julio V
Published: September 2013

Defective glucose counterregulation occurs in some insulin-dependent diabetic subjects (IDDMs) as a result of a combined deficiency of glucagon (IRG) and epinephrine (EPI) secretionin response to insulin-induced hypoglycemia. To determine whether the deficient glucagon response, the deficient epinephrine response, or both are manifestations of autonomic dysfunction, we used the pancreatic polypeptide (PP) secretory response to insulin-induced hypoglycemia as a marker for autonomic neuropathy.

Seven nondiabetic controls and 21 IDDMs were given insulin at 40 mU/kg/h after overnight euglycemia. Eight of the IDDMs had defective counterregulation (−CR), and 13 had adequate counterregulation (+ CR) by our previously published criteria. Those with −CR had a blunted EPI (δEPI = 102 ± 16 pg/ml; mean ± SEM) and PP (δPP = 12 ± 13 pg/ml) response as compared with controls (δEPI = 310 ± 49; δPP = 498 ± 43) and IDDMs with +CR (δEPI = 291 ± 32; δPP = 521 ± 86). In controls, IRG rose by 31 ± 6 pg/ml; in IDDMs, IRG failed to rise significantly above baselineregardless of counterregulatory status. Although the PP and EPI responses correlated well (r = 0.626, P < 0.001), the IRG response failed to correlate with either the EPI or the PP response.

We conclude that the deficient epinephrine, but not glucagon, secretory response to hypoglycemia in diabetic subjects is a result of autonomic neuropathy. The pancreatic polypeptide responsemay be helpful in evaluating the counterregulatory status of IDDMs before attempts at normalization of blood glucose using intensive therapeutic regimens, since a deficient pancreatic polypeptide response identifies patients with defective glucose counterregulation who have been shown previously to be at increased risk of severe hypoglycemia during intensive therapy.
Metabolic Control in Diabetic Dogs Treated with Pancreatic Autotransplants and Insulin Pumps
Authors: Albisser A M , Nomura M , Greenberg G R , McPhedran N T
Published: September 2013

Fasting metabolite and hormonal levels were studied prospectively in pancreatectomized dogs who had received grafts of their own pancreas. The results were compared with similarly diabetic animals who received exogenous insulin pumped intravenously either peripherally or portally. All animals were studied for 48–91 wk after pancreatectomy.

In the autotransplanted animals, the fasting levels of glucose, lactate, pyruvate, alanine, pancreatic glucagon, insulin, gastric inhibitory peptide, and pancreatic polypeptide were all abnormal. In the peripherally infused animals, the fasting levels of glucose, pyruvate, alanine, free fatty acids, and insulin were also abnormal. In the portally infused animals, pyruvate, alanine, gastric inhibitory peptide, gastrin, and pancreatic polypeptide were abnormal.

These results suggest that the portal route of insulin delivery may be necessary if fasting metabolite and hormonal levels are to approximate normal most closely whether exogenous intravenous insulin is replaced by implanted pumps or endogenous insulin is replaced by pancreatic transplants.
Hormone Release, Islet Yield, and Transplantation of Fetal and Neonatal Rat Dorsal and Ventral Pancreatic Islets
Authors: Hayek A , Guardian C
Published: September 2013

Fetal (20–21 day gestation) and neonatal (<5-day-old) rat islets were isolated from the glucagon-rich (dorsal) and glucagon-poor (ventral) pancreatic regions. After 1 or 2 wk in culture, groups of islets from each region were transferred to culture dishes containing Krebs-Ringer bicarbonate buffer with low (2.4 mM) and high (16.7 mM) glucose plus aminophylline. After 2 wk in culture, insulin released into medium was higher than after 1 wk, and more so if the islets originated from dorsal tissue (P < .01). Glucagon release in response to alanine (10 mM) stimulation was also significantly higher in dorsal than in ventral islets (6.38 ± 1.98 vs. 1.49 ± 0.89 pg · islet−1 · h−1 respectively; P < .02).

Coincident with higher insulin and glucagon release, islet yield was greater in tissue from the dorsal neonatal pancreas than from that obtained in the fetal and neonatal ventral pancreas [range: dorsal, 131–180 (median, 153), vs. ventral, 53–127 (median, 84), islets obtained on day 5 of culture].

Neonatal islets of dorsal origin were transplanted intrasplenically (500–3000 islets) to streptozocin-induced diabetic inbred Lewis rats. Only rats receiving >2500 islets were cured by transplantation.

These experiments show that dorsal fetal islets secrete more insulin than do ventral islets and that islet yield is higher when islets are isolated from dorsal rather than from ventral perinatal pancreatic tissue. Despite their in vitro behavior, more neonatal dorsal islets are required to cure experimental diabetes than are reported With adult islets.
β-Adrenergic Receptors and Adenylate Cyclase Activity in Diabetic Rat Fat Cells
Authors: Cingolani G E Chiappe De
Published: September 2013

Our study describes the effect of norepinephrine on adenylate cyclase activity in adipocytes from control and diabetic rats. The results show that diabetes induced an increase in both basal and norepinephrine-stimulated adenylate cyclase activity. This higher activity was not suppressed when the animals were treated for 2 days with the β-blocking agent propranolol. On the other hand, adipocytes from control animals treated with propranolol showed a higher adenylate cyclase activity (basal and in response to norepinephrine).

β-Adrenergic receptors were examined in adipocytes from control and diabetic rats with and without treatment with propranolol. The results show a higher β-receptor density in adipocytes from diabetic animals. When the animals were treated with propranolol, the pblocker induced a higher receptor density in adipocytes from control animals without affecting the already increased receptor density in diabetic preparations.

The data suggest that adenylate cyclase activity in response to norepinephrine in adipose tissue is increased during at least a certain period of the diabetic state. This increase in adenylate cyclase activity is accompanied with an increase in β-receptor density, but in contrast to control animals, this receptor density is not further increased with propranolol treatment.
Apolipoprotein E Polymorphism and Hyperlipemia in Type II Diabetics
Authors: Eto M , Watanabe K , Iwashima Y , Morikawa A , Oshima E , Sekiguchi M , Ishii K
Published: September 2013

The relationship between apolipoprotein E (apoE) polymorphism and plasma lipids and hyperlipemia was investigated in 105 male type II diabetics and 111 male nondiabetics. ApoE phenotypes were determined by a one-dimensional rapid flat gel isoelectric focusing method as described previously. The apoE phenotype frequency in diabetics was similar to that in nondiabetics.

The frequency of hyperlipemia was higher in diabetics (56.2%) than in nondiabetics (32.4%). It was highest in the apoE3/2 group of diabetics and nondiabetics, followed by the apoE4/3 and apoE3/3 groups in the order described, indicating that the susceptibility to hyperlipemia differs among the apoE phenotype groups. ApoE3/2 diabetics had significantly higher levels of apoE and very-low-density lipoprotein (VLDL) cholesterol (chol)/VLDL triglyceride (TG) ratios than apoE3/3 diabetics. The effects of diabetes mellitus on plasma lipid levels differed among the various apoE phenotype groups: i.e., plasma total chol and low-density lipoprotein (LDL) chol increased only in apoE3/2 and apoE4/3 diabetics and plasma high-density lipoprotein chol decreased only in apoE3/3 diabetics, as compared with the corresponding apoE phenotype groups of nondiabetics, whereas plasma TG, VLDL TG, and VLDL chol increased in the three apoE phenotype diabetics. Furthermore, an increase of apoEII; apoEIII ratio was observed in apoE3/3 diabetics, particularly in those with hypertriglyceridemia. This study has also shown that the increased apoEII: apoEIII ratio is due to increased sialation of apoE based on the study of sialidase digestion of apo VLDL.

We conclude that apoE polymorphism should be taken into consideration when plasma lipoprotein patterns are studied in type II diabetics and that increased sialation of apoE may at least partly contribute to an increased frequency of hypertriglyceridemia in type II diabetics.
Cold Exposure Reverses the Diabetogenic Effects of High-Fat Feeding
Authors: Vallerand André L , Lupien Jean , Bukowiecki Ludwik J
Published: September 2013

Long-term cafeteria feeding, cold exposure, and the combination of treatments increased energy intake in female Wistar rats by 25%, 113%, and 150%, respectively, in comparison with controls (P < 0.01). Although cafeteria feeding at room temperature markedly increased the insulin response to an intravenous glucose tolerance test (IVGTT), glucose tolerance was deteriorated (P < 0.01). In contrast, cold exposure significantly improved glucose tolerance in the presence of a reduced insulin response in Purina- and cafeteria-fed animals. Moreover, cold exposure also decreased body weight gain and increased brown adipose tissue mass, total cytochrome-oxidase activity, and cellularity by approximately 600–800%. The results suggest that cold exposure enhances insulin sensitivity of peripheral tissues, whereas hyperphagia on a high-fat, low-protein diet leads to insulin resistance. In addition, the results demonstrate that prolonged stimulation of energy expenditure by cold exposure not only reverses the diabetogenic effects of cafeteria feeding but also improves glucose tolerance. This phenomenon could result from a combination of two factors: (1) a cold-induced prevention of obesity; and (2) an enhanced disposal of circulating glucose into peripheral tissues, including brown adipose tissue.
Mitogenic Activity and Receptor Reactivity of Hybrid Molecules Containing Portions of the Insulin-like Growth Factor I (IGF-I), IGF-II, and Insulin Molecules
Authors: Vroede Monique A De , Rechler Matthew M , Nissley S Peter , Ogawa Hiroshi , Joshi Satish , Burke G Thompson , Katsoyannis Panayotis G
Published: September 2013

Insulin and the insulin-like growth factors IGF-I and IGF-II are thought to exert their mitogenic effects in cultured chick embryo fibroblasts and human skin fibroblasts via IGF receptors rather than via insulin receptors. These effects appear to be mediated by the type I subtype of IGF receptor, which is structurally similar to the insulin receptor and exhibits significant cross-reactivity with insulin. As a first step in our longrange goal of defining those features of the IGF-I and IGF-II molecules that confer enhanced mitogenic activity and reactivity with these mitogenic type I IGF receptors, we have prepared two hybrid insulin-IGF molecules and examined their mitogenic and binding activities: (1) A27-insulin, containing an elongated 27- residue A-chain (in which the 6-residue D-domain of IGF-II was added to the carboxy-terminus of the 21-residue A-chain of insulin) combined with the B-chain of insulin; and (2) Ainsulin-BIGF-I, containing the A-chain of insulin and the synthetic 30-residue B-domain of IGF-I. Both hybrid molecules stimulated DNA synthesis and inhibited 125I-IGF-I binding to type I IGF receptors in both chick embryo and human fibroblast cultures. A27- insulin had considerably greater mitogenic potency and binding potency than Ainsulin-BIGF-I. Neither hybrid molecule was more potent in these assays than insulin, indicating that the presence of DIGF-II,or BIGF-I, by itself was not sufficient to increase the mitogenic potency of insulin in fibroblasts. By contrast, Ainsulin-BIGF-I showed enhanced reactivity with an antiserum to IGF-I. A27-insulin retained significant insulin-like metabolic activity despite the presence of the D-domain of IGF-II.
Association Between NIDDM, RH Blood Group, and Haptoglobin Phenotype: Results from the San Antonio Heart Study
Authors: Stern Michael P , Ferrell Robert E , Rosenthal Marc , Haffner Steven M , Hazuda Helen P
Published: September 2013

We examined seven red cell antigen and 10 polymorphic protein phenotypes in 1237 Mexican Americans randomly selected from three San Antonio neighborhoods. Statistically significant associations were found between non-insulin-dependent diabetes mellitus (NIDDM) and RH blood type (X2 = 32.87, df = 10, P = 0.0003) and haptoglobin phenotype (X2 = 9.15, df = 2, P = 0.010). The haptoglobin association showed a dose effect with a single dose of the haptoglobin-1 allele associated with an approximately 50% increase and a double dose of the haptoglobin-1 allele associated with an approximately 100% increase in NIDDM prevalence. Multivariate analysis indicated statistically significant associations between NIDDM and age, sex, adiposity, and neighborhood of residence. However, even after taking these potential confounding variables into account, there was still a significant, independent association between NIDDM and haptoglobin phenotype. The results suggest that the haptoglobin gene may be in linkage disequilibrium with a major susceptibility gene for NIDDM.
Wound Collagen Accumulation in Obese Hyperglycemic Mice
Authors: Goodson William H , Hunt Thomas K
Published: September 2013

We used C57-BL ob/ob mice as a model to study wound healing in type II (adult-onset) diabetes. Planimetry was used to assess rate of closure in standard open skin wounds. In agreement with previous subcutaneous wound collagen-accumulation studies, closure was slower in the ob/ob mice.

Subcutaneous implants were used to evaluate wound collagen accumulation. Weanling mice have collagen accumulation similar to lean littermates (mean 3.43 μg/ cm vs. 3.46 μg/cm), but the same ob/ob animals had decreased wound collagen (mean 2.39 μg/cm vs. 3.02 μg/cm, P < 0.04) when mature. Other ob/ob animals fed a restricted diet (and thus not obese) had normal collagen accumulation at the same age. Neither insulin nor diet restriction restored wound collagen accumulation in phenotypically obese mice. Because collagen accumulation is not improved by measures that control hyperglycemia (insulin and diet restriction) and the defect was seen only in phenotypically obese ob/ob mice, the decreased wound collagen accumulation may be due in part to structural changes in adipose tissue.
Decreased Protein C Levels in Patients With Insulin-Dependent Type I Diabetes Mellitus
Authors: Vukovich T C , Schernthaner G
Published: September 2013

The plasma levels of protein C were investigated in 54 type I diabetic patients without retinopathy and in 14 diabetic patients with diabetic retinopathy and compared with the findings in 35 sex- and age-matched healthy control subjects. In the total group of type I diabetic patients, protein C was significantly less than in the controls. The lowest levels of protein C were found in diabetic patients with the poorest metabolic control. Protein C levels showed a significant negative correlation with the blood glucose levels, but they were not correlated with hemoglobin A1c (HbA1c). Although patients with retinopathy showed the least decrease of the plasma level of protein C among the diabetic subjects, the ratio of protein C to factor II was significantly decreased compared with the control subjects. Because the levels of coagulation factor II were not reduced in diabetic patients, the reduction of protein C seems to be caused, not by reduced synthesis in the liver, but more likely by an increased clearance from the blood plasma. The decrease of protein C in the plasma of type I diabetic patients indicates an abnormal, probably hypercoagulable, hemostatic situation in this disorder.
Studies on Mechanisms Involved in Hypoglycemia-Induced Platelet Activation
Authors: Trovati Mariella , Anfossi Giovanni , Cavalot Franco , Vitali Sara , Massucco Paola , Mularoni Elena , Schinco Piercarla , Tamponi Giacomo , Emanuelli Giorgio
Published: September 2013

The aim of our study was to investigate the mechanisms involved in hypoglycemia-induced platelet activation. Sixteen healthy male subjects received a 60-min intravenous infusion of human regular insulin at the rate of 64 mU · m−2 · min−1: throughout 150 min, we serially measured plasma concentrations of glucose, insulin, and counterregulatory hormones; platelet sensitivity to ADP, thrombin and platelet-activating factor; plasma concentrations of platelet markers for specific proteins of in vivo release reaction (β-thromboglobulin and platelet factor 4). Our study showed that insulin-induced hypoglycemia causes a significant increase in platelet sensitivity to aggregating agents in vitro and a platelet release reaction in vivo. Hypoglycemia-induced platelet activation was not correlated with plasma glucose concentrations at nadir and occurred before the increase of plasma growth hormone and cortisol.

To further elucidate the mechanisms of hypoglycemia-induced platelet activation, we incubated in vitro platelet-rich plasma (PRP) of seven fasting healthy subjects with the same concentrations of insulin, epineph-rine, glucagon, growth hormone, and cortisol measured in vivo during insulin-induced hypoglycemia. Only epinephrine was able to increase platelet sensitivity to aggregating agents. To investigate the role of α-adrenergic receptors in this phenomenon, we also studied four healthy subjects on another occasion, repeating the above-described insulin infusion together with intravenous infusion of phentolamine (–15 to + 150 min), 5 mg over 2 min followed by 500 μg/min. α-Blockade was able to suppress hypoglycemia-induced increase of platelet sensitivity to aggregating agents. A further study in vitro confirmed these results obtained in vivo, showing that incubation with phentolamine is able to inhibit the epinephrine-induced increase of platelet aggregation in response to ADP, thrombin, and platelet-activating factor.

In conclusion, insulin-induced hypoglycemia deeply influences platelet function, causing an increase of platelet sensitivity to aggregating agents in vitro and a release reaction in vivo. Through α-adrenoreceptors, epinephrine is responsible for the hypoglycemia-induced increase of platelet aggregation in response to ADP, thrombin, and platelet-activating factor.