bluuebunny/crossref_metadata_2025 huggingface dataset:
Abnormal Composition of High Density Lipoproteins in Non-insulin-dependent Diabetics
Authors: Biesbroeck Robert C , Albers John J , Wahl Patricia W , Weinberg Clarice R , Bassett Martin L , Bierman Edwin L
Published: September 2013

Atherosclerosis is the major cause of morbidity and mortality among non-insulin-dependent diabetics (NIDDM). High density lipoprotein (HDL) cholesterol levels are reportedly low in NIDDM patients, which may add to their risk of atherosclerosis. Changes in the amount and composition of HDL and the relationship of HDL cholesterol to other lipid and protein components of HDL were investigated in a well-characterized NIDDM population not receiving either insulin or oral hypoglycemic agents. Also, the levels of the lipid and protein components of HDL in the NIDDM group were compared within each sex to those in a control group of comparable age. In the NIDDM group, total triglyceride was inversely related to HDL cholesterol (P < 0.05) and positively related to HDL triglyceride (P < 0.001). There was no relationship between total triglyceride and apoprotein A-I (the major protein component of HDL). If adjustment was made for factors that may affect HDL cholesterol levels and for apoprotein A-I (which adjusts for varying numbers of HDL particles), a highly significant inverse correlation between HDL cholesterol and HDL triglycerides emerged (r = −0.71, P < 0.001), suggesting that elevated plasma triglyceride levels decreases the amount of cholesterol associated with each HDL particle rather than reducing the actual number of particles, possibly by replacing esterified cholesterol with triglyceride in the lipid core. When the NIDDM group was compared with the control group, diabetic males had lower HDL cholesterol than did controls (P < 0.01) and a trend in the same direction was noted for females. Total triglycerides were higher than control levels in diabetic men (P < 0.05) and showed a trend in the same direction in diabetic females. Concomitantly, HDL triglycerides were higher than controls in diabetic males (P < 0.01) and diabetic females (P < 0.05). However, adjustment for either total triglycerides or HDL triglycerides only partially reduced the differences in HDL cholesterol between diabetics and controls, indicating that additional factors are involved in the low HDL cholesterol levels seen in NIDDM populations. Apoprotein A-I levels were not lower in diabetic males and were actually somewhat higher in diabetic females, again suggesting a reduction of cholesterol for each HDL particle rather than a smaller number of HDL particles in these diabetics. The apoprotein A-I/ A-II ratio was higher in diabetic women than in controls (P < 0.05) and showed a trend in the same direction in diabetic men, suggesting a relative shift from the HDL3 to the HDL2 density range in the NIDDM group. Thus abnormal HDL composition is characteristic of untreated NIDDM. Their low HDL cholesterol is only in part related to increased plasma triglyceride levels.
Insulin-Induced Alterations in Insulin Binding and Insulin Action in Primary Cultures of Rat Hepatocytes
Authors: Amatruda John M , Newmeyer Holly W , Chang Cecilia L
Published: September 2013

The exposure of primary cultures of hepatocytes to insulin. 10−8 M, for 16 h results in a decrease in high affinity insulin binding with no alterations in lower affinity binding. This is reflected in a decrease in the sensitivity, but normal responsiveness, of cultured hepatocytes to the acute effect of insulin on the uptake of aminoisobutyric acid. The shift in sensitivity, however, can only be partially explained by the decrease in insulin binding. With regard to lipid synthesis, hepatocytes cultured in the presence of insulin, 10−8 M, are normally sensitive and hyperresponsive to the acute effects of insulin. These data indicate that the insensitivity or resistance of a given tissue to insulin may be specific for the biologic response being evaluated, that postbinding events may be more important than alterations in insulin binding in determining both the sensitivity and responsiveness of a tissue to insulin, and that generalizations concerning the sensitivity or responsiveness of a tissue to insulin based on binding data alone may be unwarranted.
Insulin Responses to Nonglucose Stimuli in Non-insulin-dependent Diabetes Mellitus During a Tolbutamide Infusion
Authors: Pfeifer Michael A , Halter Jeffrey B , Beard James C , Judzewitsch Roman , Porte Daniel
Published: September 2013

To determine the effect of tolbutamide on insulin release to nonglucose stimuli in non-insulin-dependent diabetes mellitus and how plasma glucose levels may modulate this effect, the acute insulin response (AIR) to an isoproterenol (12 μg) or an arginine (5 g) i.v. pulse was determined before and during a tolbutamide infusion (7.5 mg/m2/min) in 25 male subjects. During the tolbutamide infusion, there was an increase in the AIR to both isoproterenol (% Δ AIR = +49 ± 21%, N = 11, P < 0.05) and arginine (% Δ AIR = +52 ± 15%, N = 12, P < 0.005) and a decrease in plasma glucose (Δ plasma glucose for isoproterenol = −24 ± 6 mg/dl, P < 0.005; for arginine = −26 ± 3 mg/dl, P < 0.001). In separate studies, when the plasma glucose was clamped at baseline values by a variable rate of glucose infusion, there was a greater effect of tolbutamide on AIR when compared with the unclamped tolbutamide studies (isoproterenol: % Δ AIR = +132 ± 25%, P < 0.025; arginine: % Δ AIR = +95 ± 12%, P < 0.05). Thus, tolbutamide increases the AIR of nonglucose stimuli, but this augmentation by tolbutamide is blunted by the concomitant decrease in plasma glucose. Consideration of this observation is necessary when interpretating the effects of a sulfonylurea on islet cell responses.
Evidence Against Insulin Synthesis BY IM-9 Lymphocytes
Authors: Bauman William A , Hatcher Victor B , Levitt Mindy A , Yalow Rosalyn S
Published: September 2013

Insulin concentrated from acid/ethanol extracts of IMg lymphocytes by the use of octadecylsilyl (ODS) silica cartridges averaged 0.13 ng/ml cell volume compared with the 0.12 ng insulin/ml cell culture medium. The insulin content of these cells appears to be < 1% of previously reported values and probably could be accounted for by concentration of insulin from the incubation medium on cell receptors.
Nutrition and Somatomedin. IX: Blunting of Insulin-Like Activity by Inhibitor in Diabetic Rat Serum
Authors: Phillips Lawrence S , Scholz Thomas D
Published: September 2013

Poor growth in uncontrolled experimental diabetes appears due in part to increased circulating inhibitor, a factor (or factors) that blocks stimulation of growing cartilage by somatomedins. To determine if the inhibitor has other antianabolic properties, we examined effects on insulin and insulin-like action on muscle and adipose tissue. Rat epididymal fat pads were exposed to normal rat serum, somatomedins (fraction from normal rat serum) or insulin, with or without added streptozotocin-diabetic rat serum or inhibitor (fraction from diabetic serum); insulin-like activity was assessed by glucose conversion to CO2. Diabetic rat serum alone lowered glucose utilization significantly below buffer levels (P < 0.01), but inhibitor alone had no effect. However, stimulation by insulin, normal rat serum, or somatomedins was decreased significantly by both diabetic rat serum or inhibitor (P < 0.01); Lineweaver-Burk analysis suggested that such inhibition was noncompetitive. In incubations with rat diaphragm, neither diabetic rat serum nor inhibitor alone lowered glucose incorporation into glycogen, but both inhibited muscle stimulation by insulin (P < 0.01). In in vivo studies, rats given insulin with added diabetic rat serum exhibited decreased stimulation of glucose incorporation into muscle glycogen (P < 0.01) and into adipose tissue total lipids.

These observations indicate that an inhibitor in the serum of diabetic rats can brake anabolic processes is muscle (glycogen formation) and adipose tissue (glucose utilization, lipid formation). Such an inhibitor may therefore contribute to poor growth in diabetes by decreasing calorie storage due to insulin and insulin-like actions as well as skeletal elongation due to somatomedin action.
Effect of Exercise (Running) on Serum Glucose, Insulin, Glucagon, and Chromium Excretion
Authors: Anderson Richard A , Polansky Marilyn M , Bryden Noella A , Roginski Edward E , Patterson Kristine Y , Reamer Donald C
Published: September 2013

Chromium is involved in normal glucose metabolism. To test whether chromium is also associated with the exercise-induced increases in glucose utilization, urinary chromium excretion, serum glucose, insulin, and glucagon of nine male runners (23–46 yr) were evaluated. Blood samples were taken prior to, immediately following, and 2 h after a strenuous 6-mile run. Urine samples were also taken at these times, and total daily urine collections were made the day of the run and the following day. Mean serum glucose for all runners immediately after running was 185 ± 19 mg/dl compared with 90 ± 1 mg/dl (mean ± SE) prior to running. Mean serum glucagon immediately after running was significantly elevated compared with that observed prior to or 2 h after running; serum insulin levels were not altered significantly. Mean urinary chromium concentration was increased nearly five-fold 2 h after running; similar results were obtained when chromium concentration was expressed per mg of creatinine. Total daily urinary Cr excretion was approximately two times higher the day of running compared with the following nonrun day. Daily urinary excretion of sodium, potassium, and calcium were measured to determine if exercise had a general nonspecific effect on renal function; daily urinary excretion of these was not changed by exercise. These data demonstrate that accompanying the exercise-induced changes associated with increased glucose utilization, there is a significant increase in chromium excretion.
Genetic Susceptibility to the Development of Retinopathy in Insulin-dependent Diabetics
Authors: Dornan T L , Ting A , McPherson C K , Peckar C O , Mann J I , Turner R C , Morris P J
Published: September 2013

HLA types and blood glucose control were investigated in 127 insulin-dependent diabetics with different grades of severity of retinopathy. The means of all afternoon clinic blood glucose levels from the diagnosis of diabetes were 9.9 ± 2.1 mmol/L for patients with no retinopathy, 11.8 ± 2.1 mmol/L for patients with background retinopathy, and 12.4 ± 2.1 mmol/L for patients with proliferative retinopathy (P < 0.0001). HLA-DR4 was present in 61 of 87 patients (70%) with background or proliferative retinopathy and 21 of 39 (54%) with no retinopathy. The frequency of HLA-DR4 was lowest in patients with no retinopathy despite “poor control” (mean blood glucose ≥ 11.5 mmol/L) and highest in those who had developed retinopathy despite “good control;” the frequencies of HLA-DR2 showed the reverse pattern. Mantel-Haenszel tests were used to calculate the odds ratios for the presence of retinopathy associated with “poor control” and with HLA-DR4, since each modified the effect of the other. The odds ratio for retinopathy associated with “poor control” was 6.7 (P < 0.0001). The odds ratio with HLA-DR4 was 3.7 (P < 0.005). When both risk factors were present, the odds ratio increased to 33.3 (P < 0.0001). Genetically determined factors appear to influence susceptibility to retinopathy in insulin-dependent diabetics.
Acetone Metabolism During Diabetic Ketoacidosis
Authors: Owen O E , Trapp V E , Skutches C L , Mozzoli M A , Hoeldtke R D , Boden G , Reichard G A
Published: September 2013

The presence and the importance of acetone and its metabolism in diabetic ketoacidosis has largely been ignored. Therefore, we studied acetone metabolism in nine diabetic patients in moderate to severe ketoacidosis.

The concentration of acetone in plasma, urine, and breath, and the rates of acetone production and elimination in breath and urine were determined and the rates of vivo metabolism were calculated. Plasma acetone concentrations (1.55–8.91 mM) were directly related and were generally > acetoacetate concentrations (1.16–6.08 mM). The rates of acetone production ranged from 68 to 581 μmol/min/1.73 m2, indicating the heterogeneous nature of the patients studied. The average acetone production rate was 265 μmol/min/1.73 m2 and accounted for about 52% of the estimated acetoacetate production rate. Urinary excretion of acetone remained constant and accounted for about 7% of the acetone production rate in all patients. There was a positive linear relationship between the percentage of the acetone production rate accounted for by excretion in breath and the plasma acetone concentration. At low plasma acetone concentrations, ∼ 20%, and at high plasma acetone concentrations, ∼ 80% of the production rate was accounted for by breath acetone. In contrast, there was a negative linear relationship between the percentage of acetone production rate undergoing in vivo metabolism and plasma acetone concentration. At low plasma acetone concentrations, ∼ 75%, and at high concentrations, ∼ 20% of acetone production rate was accounted for by in vivo metabolism. Radioactivity from 2-[14C]-acetone was variably present in plasma acetone, glucose, lipids and proteins. No radioactivity was found in plasma acetoacetate, beta-hydroxy butyrate or free fatty acids or other anionic compounds. Exchange rates of acetone into other metabolites could not be estimated because of non-steady-state precursor product relationships in these patients.
Stimulatory Effect of Beta-Hydroxybutyrate on the Release of Somatostatin from the Isolated Pancreas of Normal and Streptozotocin-Diabetic Dogs
Authors: Hermansen K
Published: September 2013

The present investigation was undertaken to ascertain whether the ketone body, beta-hydroxybutyrate (BOH), affects the somatostatin secretion from the isolated pancreas of normal and streptozotocin (STZ)-diabetic dogs. We found (1) that the addition of 10 mM DL-BOH to the perfusate augmented somatostatin secretion from the normal dog pancreas. The responses obtained were, however, modified by the prevailing glucose level with higher responses appearing at high (11 mM) rather than at zero glucose. The effect of BOH could not be attributed to changes in osmolarity, Na+, or H+ concentrations. (2) BOH at doses well within the physiologic and pathophysiologic range stimulated the secretion of somatostatin from the normal pancreas in a dose-dependent manner. The threshold concentration was close to 1 mM corresponding to 0.5 mM of the biologically active D form. (3) In the STZ-diabetic dogs, BOH (1–20 mM) elicits a dose-related enhancement of the pancreatic somatostatin secretion. In the two groups, identical D-cell responses were obtained at 3, 10, and 20 mM BOH.

The results demonstrate that physiologic levels of BOH stimulates the release of somatostatin from pancreas of normal and STZ-diabetic dogs, thereby providing support for a physiologic influence of BOH over the secretory function of the pancreatic D-cell. The possible existence of a BOH-somatostatin feed-back mechanism operating in the diabetic organism is discussed.
Nonenzymatic Glycosylation of Proteins: Structure and Function Changes
Authors: Means Gary E , Chang Min Kun
Published: September 2013

The importance of carbohydrate and protein structure on the nonenzymatic glycosylation of proteins is discussed on the basis of limited model compound studies. Rates of giycosyiation presumably depend on the proportion of sugar present in the carbonyl form, on the amine basicity, and on its steric accessibility. The thermodynamic stability of the resulting glycosylamino moieties, which presumably depend in part on the protein structure may, however, be the most important factor in determining the extent of their reaction.
Nonenzymatic Browning Products: Physiologic Effects and Metabolic Transit in Relation to Chemical Structure. A Review
Authors: Finot P-A
Published: September 2013

The Maillard reaction between reducing sugars and free amino acids and proteins occurs readily during the preparation and storage of foods. This reaction, which evolves through several steps, leads to irreversible modification of the molecules involved. The subsequent nutritional and physiologic effects are due to both the loss of the availability of essential amino acids and to the presence of the new molecules formed.

In food proteins, the reaction involving lysine is the most important nutritionally. The deoxyketosyl-lysine molecule formed in the “early” stage of the reaction is not available biologically. In the “advanced” stage of the reaction, which produces browning, the digestibility of the protein is decreased and other amino acids are destroyed.

The metabolic transit and the nutritional and physiologic effects of the different groups of substances produced are described. The deoxyketosyl derivatives are partly absorbed and excreted in the urine without biochemical modification. The premelanoidins also are partly absorbed but are metabolized in the organism; the most representative groups of derivatives are biochemically transformed into acids (hydroxymethyl furfural, reductones) or glucurono or sulfo conjugates (pyrazines, maltol) before excretion in the urine; they have antiphysiologic effects. The melanoidins (molecules of high molecular weight) are not absorbed and their effects are negligible. The possible occurrence of Maillard-type reactions in living organisms is also discussed.
Nutritional and Toxicologic Effects of Nonenzymatic Maillard Browning
Authors: Lee Tung-Ching , Pintauro S J , Chichester C O
Published: September 2013

The Maillard nonenzymatic browning reaction is known to cause serious reduction in the nutritionai value of foods. The reduced nutritionai value does not seem to be limited to the loss of amino acids, as supplementation of the diet with those amino acids does not completely restore its biologic value. When rats were fed a browned egg albumin diet and a control diet of equal protein quality for up to 12 mo, the rats fed browned diet showed enlarged cecums, livers, and kidneys and reduced weight gain. In addition, intestinal digestive enzyme activities decreased, and serum alkaline phosphatase and serum glutamic oxaloacetic transaminase (GOT) activities increased compared to the control group. The livers of the rats fed browned protein showed histopathologic changes including fatty change and an unknown pigment accumulation. The data indicate a possible cumulative toxic effect due to the long-term feeding of Maillard browned compounds.

The mutagenic activity of Maillard browned egg albumin was also tested. No mutagenic effect was observed. The products of the nitrosation of the Amadori compound fructosyl-L-trytophan were mutagenic, however, in strains TA 1535 and TA 100 of the Salmonella/mammalian microsome mutagenicity assay.
Glucosylation of Human Collagen
Authors: Kohn Robert R , Schnider Stuart L
Published: September 2013

Many of She debilities that characterize the aging syndrome can be explained by cross-linking of macromol-ecules such as collagen. And several of the characteristic complications of diabetes mellitus resemble age-like changes in collagen-rich tissues. In this laboratory, studies of human collagen that is not the site of lesions have revealed an age-related decrease in susceptibility to collagenase digestion and increased glucosylation of tendon collagen, both markedly increased in diabetes. An age-related decrease in solubility and an increase in glucosylation of skin collagen, both also markedly increased in diabetes, were also observed. Glucosylation of skin collagen was less than that of tendon, possibly because of the greater turnover of skin collagen. Collagen alterations in diabetes were most apparent in samples from younger adult subjects. Samples from older diabetics gave values within the range of nondiabetics, suggesting that the degree to which collagen can be cross-linked or glucosyiated is limited, and that limits may be attained at earlier ages in diabetes.

The association between glucosylation and cross-linking of collagen suggests that glucosylation may cause cross-linking, as has been shown to occur in albumin and eye lens protein.

Both the cross-linking of collagen occurring in maturation and glucosylation of protein involve the -amino group of lysine. If blood glucose is high during periods of collagen synthesis, namely during growth or fi-brosis, it is conceivable that lysine and hydroxylysine are glucosyiated rather than deaminated to form normal cross-links, and that an abnormal collagen forms that plays a role in the complications of diabetes. Control of diabetes during periods of collagen synthesis would then be a critical factor in preventing subsequent complications.

Epidemiologie studies of collagen properties, bearing on questions about the roles of genetic factors and control of diabetes in alterations in collagen and in complications of diabetes, would be feasible by the use Of skin biopsies.
Chemically Reactive and Unreactive Lysine as an Index of Browning
Authors: Friedman Mendel
Published: September 2013

The highly reactive ε-NH2 group of the essential amin acid lysine interacts with food constituents, especiailly carbohydrates, to become chemically and nutritionally unavailable. Several assays have been developed to measure reactive (available) and unreactive (unavailable) lysine in proteins. These depend on reaction of chemically accessible ε-NH2 groups with (1) fluorodini trobenzene (FDNB); (2) trinitrobenzenesulfonic acid (TNBS); (3) O-methylisourea (OMI); (4) conjugated vinyl compounds such as methyl acrylate (MA), methyl vinyl sulfone (MVS), ethyl vinyl sulfone (EVS), and phenyl vinyl sulfone (PVS); (5) S-ethyl trifluorothioacetate; (6) acid dyes; and (7) Ninhydrin. An ideal reagent for this purpose should selectively modify ε-NH2 groups under mild conditions to a derivative that is stable to protein acid hydrolysis and that can be assayed by standard amino acid analysis and spectroscopic techniques. Proposed and potential new methods for reactive lysine are critically discussed in terms of these requirements.
Islet Changes Induced by Hyperglycemia in Rats: Effect of Insulin or Chlorpropamide Therapy
Authors: Clark A , Bown E , King T , Vanhegan R I , Turner R C
Published: September 2013

To investigate the effect of hyperglycemia on normal islets, rats were made diabetic by a 95﹪ partial pancreatectomy and treated with insulin, saline, or chlorpropamide for 3 mo. Histologic examination and morphometry of the residual pancreas showed islet enlargement and fibrosis that correlated with the mean lasting plasma glucose during the experimental period. Treatment of diabetes with insulin prevented the islet disorganization. The B-cell area per islet remained constant and was not affected by hyperglycemia. Chlorpropamide had little effect on the fasting plasma glucose or islet structure, and no “μ-cytotrophic” effect was seen. Chronic hyperglycemia induces islet damage that may affect residual B-cell function in diabetes.
Insulin Sensitivity, Binding, and Kinetics in Pancreatogenic and Type I Diabetes
Authors: Nosadini Romano , Prato Stefano Del , Tiengo Antonio , Duner Elena , Toffolo Gianna , Cobelli Claudio , Faronato Pier Paolo , Moghetti Paolo , Muggeo Michele
Published: September 2013

Pancreatogenic diabetes (PD), secondary either to chronic calcific pancreatitis or to pancreatectomy, is characterized by higher frequency of hypoglycemic events during insulin therapy in comparison with type I insulin-dependent diabetes (IDD). Not only glucagon deficiency, but an enhanced peripheral tissue sensitivity to insulin could account for this metabolic behavior. We investigated several facets of insulin action, e.g., tissue sensitivity to insulin, insulin binding to red cells, and insulin kinetics in seven patients with PD in comparison with type I. Tissue sensitivity to insulin was evaluated by means of the glucose-insulin clamp technique as M/I × 100 ratio (mg · kg ·−1 min−1/μU · ml−1), where M is the amount of glucose infused by Biostator GCIIS to clamp BG at basal level and I is the free insulin plateau concentration achieved by a primed-constant insulin infusion.

At high BG 15 h after the last injection of regular insulin M/I × 100 was 7.79 (range 4.25–9.75) in PD and 4.20 (range 1.20–6.91) in D (P < 0.05). At low and equal BG M/I × 100 was 8.55 (range 6.35–9.72) in PD and 3.42 (range 1.19–6.75) in D (P < 0.01). The rate of endogenous glucose production was nearly totally suppressed in both groups of patients. Just before the two clamps, 125I-insulin specific binding to red cells was studied. The maximum specific binding was significantly higher in PD than in D at high BG (10.7 ± 1.7 vs. 7.4 ± 0.8/109 red cells) and at low and equal BG (12.4 ± 1.2 vs. 6.8 ± 0.8). Receptor concentration also was significantly higher in PD thant in D (P < 0.02) while no significant differences were found in high affinity (K̄e). Insulin kinetic data were analysed by using both “Model independent” (or noncompartmental) method and compartmental modeling. Patients with PD had significantly higher (P < 0.05) plasma clearance of insulin.

In conclusion, these data demonstrate that patients with PD are characterized by increased insulin binding sites associated with an increased insulin sensitivity and clearance rate in comparison with type I insulindependent diabetes.
Examination of Insulin Formulations Using Quasi-Elastic Light Scattering
Authors: Martindale H , Marsh J , Hallett F R , Albisser A M
Published: September 2013

A selection of neutral insulin formulations from commercially available vials was examined by quasi-elastic light scattering. In preliminary investigation, significant differences in the particulate nature of insulins from different manufacturers were apparent. Some preparations contained only small diameter species believed to be insulin hexamer while others showed evidence of larger aggregates and microcrystals. Addition of small amounts of bicarbonate had no detectable effect on the small species but dissolves the microcrystals. Speculation on further and more quantitative use of this new technique for analysis of insulin solutions is reported.
A Glucose-Containing Fraction Extracted from the Young Erythrocyte Membrane is Capable of Transferring Glucose to Hemoglobin in Vitro
Authors: Gillery Philippe , Maquart François-Xavier , Gattegno Liliane , Randoux Alain , Cornillot Pierre , Borel Jacques Paul
Published: September 2013

Red blood cell (RBC) membranes are rich in a glycoconjugate that is extractable in chloroform/methanol solutions (2/1, v/v) and contains several hexoses, such as glucose. Old and young RBC are separated and their respective glycoconjugates are prepared. HbA0 is purified by column chromatography and incubated with solutions of this conjugate. After 24-h incubation, Hb is dialyzed and the amount of glycosylated Hb is measured by a method of column chromatography adapted from Trivelli. A very significant amount of HBA1c is formed when young RBC extracts are incubated: 3.6﹪ of total Hb becomes HBA1c with the extracts, versus 3.2﹪ with free glucose, and only 2.5﹪ for controls. No increase in HbA1c is obtained when extracts of old RBC are incubated. Another difference between the action of the glycoconjugate and free glucose is that the former induces the increase of only the HBA1c fraction, whereas glucose induces the increase of all the minor Hb fractions. The evaluation of glucose contained in the conjugate before and after the glycosylation reaction demonstrates that it is due to an exchange of glucose units from the conjugate to Hb. The reaction is stereospecifically inhibited by p-nitrophenyl-β-D-glucoside. The nature of the formed HbA1c is demonstrated by isoelectric focusing. A slight increase of HbA1c observed in the incubated controls may be due to an internal migration of some residues of glucose primitively bound to lysyl residues in an unstable form and also to some degree of denaturation during the incubation.
Organ Culture of Fetal Mouse and Fetal Human Pancreatic Islets for Allografting
Authors: Mandel T E , Hoffman L , Collier S , Carter W M , Koulmanda M
Published: September 2013

In organ culture of fetal human and fetal murine pancreas under “conventional” conditions (10% CO2 in air), the islet cells of both species survive, proliferate and function but the acinar tissue rapidly degenerates. Fetal mouse islet cells also survive in 90% CO2 but nonendocrine cells, including fibroblasts and macrophages, degenerate. Fetal mouse islets grown in 90% O2 show diminished immunogenicity when transplanted into recipients differing across the entire MHC, but a reduced allograft response by the host is frequently still present in the absence of immunosuppresslon. Fetal human islets, grown in 10% C02 in air, produce insulin in vitro for prolonged periods, and as xenografts, differentiate under the kidney capsule of athymlc mice, suggesting that under appropriate conditions both in vitro and in vivo, the fetal human islets can survive. However, fetal human pancreatic cells of all types are highly susceptible to high oxygen concentrations and are rapidly killed. Because of the susceptibility of fetal human pancreas to oxygen, conditions for the culture of fetal human islets for allotransplantation may need to be modified from those tolerated by fetal mouse islets. Fetal human islets may be a useful source of transplant material in human insulin-dependent diabetes, but it is likely that tissue matching and immunosuppression may be required in addition to modification of islet immunogenicity by prior organ culture.
Reversal of Hyperglycemia by Intrasplenic Transplantation of 4-Week-Cultured Allogeneic Mouse Islets
Authors: Andersson Arne
Published: September 2013

Culture of isolated mouse pancreatic islets in RPMI 1640 for 4 wk with maintenance of specific functions is possible, although a considerable reduction of the number of surviving islets was observed. Culture in medium TC 199 resulted in a lower islet loss, but such islets were functionally less competent. Noncultured C57BL/6J (H-2b) islets were rapidly rejected when allografted intrasplenically into alloxan-diabetic but nonimmunosuppressed C57BL/KsJ (H-2d) mice. By contrast, the immunogenicity of C57BL/6J islets cultured for 4 wk at 37°C in RPM1 1640 and an air-carbon dioxide atmosphere was markedly reduced as evidenced by their ability to partly or completely normalize the hyperglycemia of nonimmunosuppressed alloxan-diabetic C57BL/KsJ mice for several weeks. Both intact islets and islets undergoing rejection were found in the spleens. The present data suggest that in vitro culture for 4 wk may reduce the immunogenicity of the islets, although a complete suppression is not achieved.
Transplantation of Islet Cells Across Major Histocompatibility Barriers After Total Lymphoid Irradiation and Infusion of Allogeneic Bone Marrow Cells
Authors: Britt Lunzy D , Scharp David W , Lacy Paul E , Slavin Shimon
Published: September 2013

Diabetic Lewis rats (AgB1/L) were evaluated as recipients of allogeneic Wistar-Furth (AgB2/2) isolated adult islets without the use of standard recipient immunosuppression. One group was treated with fractionated total lymphoid irradiation (TLI) and Wistar-Furth bone marrow cell reconstitution to proven chimerism prior to islet transplantation. This group returned to a prediabetic state following Wistar-Furth islet transplantation without any evidence of rejection for 100 days posttranspiant. A second group of Lewis rats received only TLI without bone marrow treatment. They gave a varying result following islet transplantation with one recipient showing evidence of prolonged islet survival. A third chimeric control group did not receive isolated islets and did not alter their diabetic state. A fourth group was not given TL6 nor donor bone marrow cells and uniformly rejected their allogeneic islets by 7 days. Thus, allogeneic adult islets will survive across major rat histocompatabiiity barriers using TLS and donor bone marrow chimerism as the only form of immunosuppression.
Use of Total Lymphoid Irradiation in Transplantation of Rat Fetal Pancreases
Authors: Mullen Yoko , Shibukawa Renee L
Published: September 2013

The objective of this study was to determine the effectiveness of total lymphoid irradiation (TLI) treatment of the induction of unresponsiveness to allogeneic whoie fetal pancreas tissues, which are highly immunogenic (control survival times in three combinations: <10 days). Streptozotocin-diabetic Lewis male rats were irradiated 4–5 times a week with a daily dose of 200 rads under a lead shield covering the skull, lungs, hind legs, pelvis, and tail. The spleen, thymus, and major lymph nodes were exposed to radiation. When the desired total TLI dose was reached, the rats were injected with 1–3 × 108 donor-type aduit bone marrow cells within one day after TLL, followed by fetal pancreas transplants under the kidney capsule between 1 and 35 days after TLI. Three strain combinations with immunogenetic barriers ranging from moderate (non-Rt1) to strong (Rt1) were used to determine a minimum effective dose for the permanent acceptance of pancreas allografts.

Fischer → Lewis fetal pancreases identical at Rt1 but differing at multiple non-Rt1 loci were accepted permanently in the recipients who were treated with 1200 rads TLI and 108 donor bone marrow cells. Diabetes was permanently reversed or significantly improved. A minimum effective TLI dose in this combination was found to be 1000 rads. (Buffalo × Lewis)F1 → Lewis fetal pancreas grafts across strong Rt1 barriers required at least a total TLI dose of 2600 rads, when semiallogeneic F1 bone marrow cells were used. A higher dose (3000 rads) was required, when 1–3 × 108 of fully allogeneic Buffalo bone marrow ceils were grafted. Even then, only a part of the group of treated Lewis became unresponsive to donor tissues. Removal of the pelvic shield, however, resulted in consistent development of a high percentage of donor bone marrow chimera and permanent acceptance of allografts in Buffalo or F1 × Lewis combinations. This procedure exposed the whole pelvic area and part of the femur along with the portions exposed by the complete lead shield procedure. Donor-type bone marrow grafting, in addition to TLI, was essentiai for permanent acceptance of allografts.
Subcutaneous Peritoneal Access Device for Type I Diabetic Patients Nonresponsive to Subcutaneous Insulin
Authors: Schade David S , Eaton R Phillip , Warhol Richard M , Gregory Jay A , Doberneck Raymond C
Published: September 2013

Three type I diabetic patients nonresponsive to subcutaneous insulin were implanted with a subcutaneous peritoneal access device. In these patients, multiple subcutaneous injections had been unable to prevent recurrent hospital admissions for diabetic ketoacidosis. The patients were responsive to intravenous insulin but had limited accessible peripheral veins. Complications of thrombosis and/or septicemia from permanent central venous catheters prevented the long-term use of this route.

The peritoneal access device was implanted subcutaneously adjacent to the umbilicus with its insulin delivery catheter terminating in the peritoneal space. Transcutaneous injection of insulin into the subcutaneous access port resulted in the same quantity of insulin entering the peritoneal space. Using a mixture of regular and protamine zinc insulin in a ration of 1:1 resulted in acute increases in plasma free insulin concentration with meals and a declining background level postprandially. All peritoneal access devices have been functioning well for at least 2 mo and in one of the implanted diabetic subjects, it has been in continuous use for 5 mo with no evidence of peritonitis or resistance to peritoneal insulin. These results suggest that a subcutaneous peritoneal access device may provide an alterative insulin delivery route for patients who are nonresponsive to subcutaneous insulin injections.
Evidence for the Presence of Somatostatin 28 in Plasma
Authors: Shoelson S , Polonsky K , Docherty H , Jaspan J , Rubenstein A
Published: September 2013

Somatostatin-like immunoreactivity (SLI) from dog and rat plasma eluted from Biogel P-6 columns as three distinct peaks. A large-molecular-weight peak was present in the void volume of the column, an intermediate-sized peak (SLI28) coeluted with synthetic somatostatin 28 (S-28), and a small-molecular-weight peak (SLI14) coeluted with SRIF. Material from the SLI28 peak diluted in parallel to the S-28 standard in the radioimmunoassay and behaved identically to S-28 on high pressure liquid chromatography (HPLC). Levels of SLI28 in the portal vein were consistently > the simultaneously measured peripheral levels (portal peripheral ratio 2.2 ± 0.2). Venous samples drawn from multiple sites suggested that SLI28 is segregated by the duodenum and/or pancreas and the intestine. This data is consistent with the possibility that S-28 is a hormone distinct from SRIF.
Special Comment: Meticulous Control of Diabetes: Benefits, Risks, and Precautions
Authors: Unger Roger H
Published: September 2013

Meticulous metabolic management of diabetes has become a feasible therapeutic option now being offered to increasing numbers of diabetics in the hope of delaying or preventing diabetic complications. This hope, while still untested by rigorous clinical trials, is nevertheless supported by a considerable body of scientific and clinical data (see ref. 1 for a review) and could well represent the first truly significant therapeutic advance since the discovery of insulin. Recently, however, several reports of unexpected deaths have occurred in patients “tightly” controlled with open-loop insulin delivery devices. At least some of these deaths are believed to have been directly or indirectly attributable to hypoglycemia. These reports, together with new understanding of the hormonal and metabolic lesions in treated and untreated type I diabetes, have raised legitimate questions as to the safety of efforts to normalize glycemia, whether by continuous subcutaneous insulin infusion or by multiple injections. In this review, the potential long-term benefits of meticulous glucoregulation will be weighed against the short-term risks, particularly the risk of hypoglycemic brain damage, and guidelines will be proposed in the hope of reducing the risk-benefit ratio of such regimens to an absolute minimum.
Glucose Modulation of Insulin and Glucagon Secretion in Nondiabetic and Diabetic Man
Authors: Hollander Priscilla M , Asplin Christopher M , Palmer Jerry P
Published: September 2013

To ascertain whether the ability of glucose to influence the pancreatic islets response to a nonglucose stimulus is normal in type II diabetics, we have evaluated the modulating effect (Md) of the plasma glucose level (PG) on the acute insulin response (IRI) and glucagon response (IRG) to intravenous arginine in noninsulin-dependent diabetics (NIDDM) and nondiabetics (ND). MdIRI or MdIRG is the change in the hormonal response to arginine resulting from changes in plasma glucose level divided by the change in plasma glucose. Md has been determined over two ranges of PG: between normal fasting PG (level I) and mild hyperglycemia (∼160 mg/dl, level II) and between mild hyperglycemia and marked hyperglycemia (∼350 mg/dl, level III). Increases in PG augmented the IRI response in both groups, but the degree of augmentation was impaired in the NIDOM group. MDIRI, for ND and NIDDM between levels I and II were 20 ± 3 and 1.9 ± 0.6, respectively, and between levels II and III were 23 ± 5 and 2.3 ± 0.5, respectively (P < 0.01). MdIRI correlated with fasting PG in ND and NIDDM. Changes in PG resulted in equivalent changes in the IRG response to arginine in both groups. MdIRG for level I to II was −6.1 ±1.0 and −6.0 ± 1.2, and for level II and III was −0.9 ± 0.4 and −1.2 ± 0.5 in ND and NIDDM, respectively. The impairment of MDIRI and its relationship to fasting PG in NIDDM support the hypothesis that fasting hyperglycemia may be, in part, a compensatory mechanism for maintaining beta-cell response to nonglucose stimuli, thereby maintaining basal insulin levels. MdIRG was normal in NIDDM when evaluated at comparable glucose levels in the ND and NIDDM groups.
Partial Characterization of an Insulin-dependent Serum Factor that Regulates Ornithine Decarboxylase in Skeletal Muscle
Authors: Conover Cheryl , Jaime Rozovski S , Ruderman Neil B
Published: September 2013

We have previously shown that a factor(s) in rat serum induces ornithine decarboxylase (ODC) in incubated muscle and that its activity is diminished in sera from diabetic rats. To characterize this factor further, we have studied some of its physicochemical and biologic properties. As judged from its ability to induce ODC in the incubated rat soleus muscle, the factor is protease-sensitive and both heat- and acidstable. In untreated whole serum its activity is associated with a high-molecular-weight fraction whereas after boiling at pH 5.5, activity is principally in a fraction with a molecular weight between 3500 and 12,000 daltons. The activity of the factor is diminished in hypophysectomized, starved, and aged as well as diabetic rats. In diabetic rat serum it is restored to normal by the addition of a purified somatomedin, multiplication-stimulating activity. These findings suggest that the “ODC inducing factor” is a low-molecular- weight peptide and that it has many of the characteristics of a somatomedin.
Islet Cell Antibodies and Histocompatibility Antigens (HLA) in Insulin-Dependent Diabetics and Their First-Degree Relatives
Authors: Barbosa Jose , Chavers Blanche , Dunsworth Tim , Michael Alfred
Published: September 2013

We have studied HLA A, B, D, and DR and cytoplasmic islet cell antibodies (CICA) in 282 insulin-dependent diabetics (IDD) and 806 of their nondiabetic first-degree relatives. Fifty percent of the patients were positive in the first year of disease, but only 19% among those with disease for longer than 5 yr. No associations were found between CICA and HLA types, age at diagnosis, or family history. In the relatives of IDD patients CICA was present in (2.6%) of the sibs of the probands, (5.8%) of the parents, and (6.0%) of the children.
In Vitro Injury of Porcine Aortic Endothelial Cells by Very-Low-Density Lipoproteins from Diabetic Rat Serum
Authors: Arbogast Bradley W , Lee Greta M , Raymond Thomas L
Published: September 2013

Primary cultures of porcine aortic endothelial cells were used to detect injurious agents in diabetic rat serum. Media containing normal or diabetic serum (streptozotocin-induced) were incubated with subconfluent primary cultures of endothelial cells. Cells exposed to 17% diabetic serum were severely contracted and permeable to trypan blue after 18 h. Cultures in normal serum contained significantly more protein (P < 0.005) than cultures in diabetic serum after 1 day. When normal and diabetic serum were mixed in different proportions and added to cells at 17% total serum concentration, a 50% reduction from growth in normal serum occurred at a ratio of 1 part diabetic serum to 9 parts normal serum. The toxicity of diabetic serum was not altered by heat inactivation. Administration of insulin to diabetic rats reversed both cytotoxicity and elevated triglyceride levels. Serum triglyceride levels were inversely correlated with endothelial cell growth (r = −0.878, P < 0.001). In vitro addition of up to 1 U/ml insulin to cultures in diabetic serum did not alter toxicity. Ultracentrifugal flotation of diabetic serum demonstrated the toxic substance to be entirely localized in the very-low-density lipoprotein fraction (d < 1.006 g/ml). A pool of d > 1.006 fractions from diabetic serum supported growth equivalent to normal serum. Diabetic serum contains a substance localized in the very-low-density lipoprotein fraction that is severely toxic to aortic endothelial cells in vitro. Very-low-density lipoprotein injury of endothelial cells may play an important role in the development of arterial vascular disease in insulin-dependent diabetes.
Human and Porcine Regular Insulins Are Equally Effective in Subcutaneous Replacement Therapy: Results of a Double-Blind Crossover Study in Type I Diabetic Patients with Continuous Subcutaneous Insulin Infusion
Authors: Sonnenberg G E , Chantelau E , Sundermann S , Hauff C , Berger M
Published: September 2013

Semisynthetic human Actrapid insulin (HAI, Novo, Copenhagen) was tested against porcine Actrapid insulin (PAI, Novo, Copenhagen) in 12 type I diabetic patients treated with continuous subcutaneous insulin infusion (CSII). In a double-blind crossover trial each patient received both types of insulin over a 3-wk period, respectively. No significant differences between HAI and PAI were observed in the following parameters: mean blood glucose levels (MBG) of 3–6 measurements per day (129 ± 5 versus 125 ± 4 mg/dl, means ± SEM), mean maximal excursions of blood glucose during the day (107 ± 6.6 versus 107 ± 6.9 mg/dl), total dally insulin requirements (sum of basal and premeal insulin doses, 45.7 ± 1.4 versus 42.7 ± 1.4 U/day), and a mean of weekly determined hemoglobin A1c values (7.77 ± 0.13 versus 7.83 ± 0.14% of total hemoglobin); the frequency of mild hypoglycemic episodes was similar with the two insulins. Thus, under the controlled conditions of CSII, semisynthetic human and porcine regular insulin preparations are of identical efficacy in type I diabetic patients at near normoglycemia.
Effects of Glucose on Proinsulin Messenger RNA in Rats In Vivo
Authors: Giddings Stephen J , Chirgwin John , Permutt M Alan
Published: September 2013

The purpose of these studies was to determine whether glucose, the principal regulator of insulin biosynthesis in mammals, controls synthesis through alterations in levels of proinsulin mRNA in whole animals. Rats were starved for 3 days and then either refed or injected with glucose or saline for 24 h. Glucose injection raised plasma glucose levels equivalent to levels seen with refeeding but provided less than 20% of caloric replacement. Pancreatic RNA was extracted and the relative concentration of proinsulin mRNA was determined by blot hybridization with a cloned rat proinsulin cDNA probe. In starved animals proinsulin mRNA levels were 15–20% that of fed controls. Glucose injection produced a specific three- to fourfold increase in proinsulin mRNA levels relative to total pancreatic RNA, within 24 h. The effect was measurable 2 h after glucose injection and appeared largely complete by 12 h. Actinomycin D blocked the glucose-induced increase in proinsulin mRNA.

These studies demonstrate effects of changes of plasma glucose on levels of proinsulin mRNA. Their rapidity of onset and large magnitude are comparable to effects of glucose on rates of insulin biosynthesis in isolated islets and suggest that insulin biosynthesis is regulated at least in part by levels of proinsulin mRNA.