Prediabetes, undiagnosed diabetes and diabetes risk in Italy in 2017-2018: results from the first National screening campaign in community pharmacies.

BACKGROUND: Effective policies for diabetes prevention remain urgent. We conducted a mass screening campaign in Italy to identify subjects potentially having undiagnosed diabetes, prediabetes or at diabetes risk. METHODS: This cohort study was conducted in community pharmacies joining the unitary National federation of pharmacy holders (Federfarma) and participating in the 7-day screening campaign 'DiaDay' in 2017-2018. Capillary blood glucose levels and the risk of developing diabetes in 10 years (through the Finnish Diabetes Risk Score) were assessed. RESULTS: 145 651 volunteers aged ≥20 years without known diabetes were screened at 5671 community pharmacies in 2017 and 116 097 at 5112 in 2018. Overall, 3.6% had glucose values suggestive of undiagnosed diabetes; under fasting conditions (N = 94 076), 39.9% and 16.4% had values suggestive of prediabetes by the American Diabetes Association and the World Health Organization criteria, respectively. Of those without diabetes (N = 252 440), 19.2% had scores compatible with a high risk (1:3) and 2.7% with a very high risk (1:2) of developing the disease; in the prediabetes group, the risk rose with higher impaired fasting glucose values. CONCLUSIONS: DiaDay, the first National screening campaign, highlights the need to screen the population and the key role of the pharmacist both in screening activities and education promotion.

Pioglitazone Randomised Italian Study on Metabolic Syndrome (PRISMA): effect of pioglitazone with metformin on HDL-C levels in Type 2 diabetic patients.

BACKGROUND: Previous evidence indicates that pioglitazone may improve dyslipidemia in patients with Type 2 diabetes mellitus (T2DM). AIM: The primary objective of this study was to evaluate the effect of either pioglitazone or placebo with metformin on levels of serum HDL cholesterol (HDL-C) in patients with T2DM. A secondary objective evaluated changes in metabolic syndrome (MS)-specific parameters. SUBJECTS AND METHODS: This multicenter, double-blind, randomized study was performed in patients with T2DM treated with metformin and hemoglobin A1c (HbA1c) levels between 6-8%, central obesity and reduced HDL-C. MS was evaluated from global changes in parameter values and expressed as a single factorial score following multivariate analysis of each parameter. 213 patients (110 in the pioglitazone group and 103 in the placebo group) were available for intention-to-treat analysis. RESULTS: Pioglitazone-treated patients showed a significant increase in HDL-C compared to placebo group (6.3 mg/dl vs 3.0 mg/dl; p<0.01) in addition to a greater reduction in the extent of MS (-13.2 vs -4.9; p=0.0055). Upon study completion, patients treated with pioglitazone had lower levels of HbA1c (6.41±0.65 vs 6.96±0.74%; p<0.001) and homeostasis model assessment-insulin resistance (HOMA-IR) (2.88±1.95 vs 4.68±3.63; p=0.013) and a reduction of the atherogenic LDL subfraction (pattern B) (-5.7%). CONCLUSIONS: The beneficial effects observed in pioglitazone-treated patients in the present study, (i.e. the increase in HDL-C and the reduction of insulin resistance and atherogenic LDL subfractions), support findings from the PROactive trial, where pioglitazone showed pleiotropic effects and reduced death, fatal myocardial infarction (MI) and non-fatal MI in T2DM patients with MS. Furthermore, medication used in this study showed good tolerability.

Recreational use of GHB and prescribed drugs: the challenge in forensic and clinical toxicology.

ABSTRACT: The dual nature and the double use of γ-hydroxybutyric acid (GHB) are the fundamentals of its spread as recreational drug. Endo-genously, GHB acts as inhibitory neurotransmitter while exogenously it is administered in the form of sodium oxybate to treat cataplexy and to menage alcohol withdrawal. Illicit GHB is extensively used along with prescribed drugs and drugs of abuse for its euphoric and anabolic effects. Since it has been used as incapacitating agent to perpetrate rapes and commit robberies, GHB represents a social and public health issues. The tight window of detectability in biological matrices and the difficultly to read symptoms of polydrug overdose represent the modern challenges in forensic and clinical toxicology.

Phytoextraction efficiency of Pteris vittata grown on a naturally As-rich soil and characterization of As-resistant rhizosphere bacteria.

This study evaluated the phytoextraction capacity of the fern Pteris vittata grown on a natural arsenic-rich soil of volcanic-origin from the Viterbo area in central Italy. This calcareous soil is characterized by an average arsenic concentration of 750 mg kg-1, of which 28% is bioavailable. By means of micro-energy dispersive X-ray fluorescence spectrometry (µ-XRF) we detected As in P. vittata fronds after just 10 days of growth, while a high As concentrations in fronds (5,000 mg kg-1), determined by Inductively coupled plasma-optical emission spectrometry (ICP-OES), was reached after 5.5 months. Sixteen arsenate-tolerant bacterial strains were isolated from the P. vittata rhizosphere, a majority of which belong to the Bacillus genus, and of this majority only two have been previously associated with As. Six bacterial isolates were highly As-resistant (> 100 mM) two of which, homologous to Paenarthrobacter ureafaciens and Beijerinckia fluminensis, produced a high amount of IAA and siderophores and have never been isolated from P. vittata roots. Furthermore, five isolates contained the arsenate reductase gene (arsC). We conclude that P. vittata can efficiently phytoextract As when grown on this natural As-rich soil and a consortium of bacteria, largely different from that usually found in As-polluted soils, has been found in P. vittata rhizosphere.

Incidence of severe nocturnal hypoglycemia in patients with type 1 diabetes treated with insulin lispro or regular human insulin in addition to basal insulin glargine.

BACKGROUND AND AIMS: Once-daily (OD) basal insulin glargine (GLA) can be used as part of a multiple daily injection regimen in patients with type 1 diabetes mellitus. This randomized, multicenter study compared GLA+prandial regular human insulin (RHI) with GLA+prandial insulin lispro (LIS) in reducing the incidence of severe nocturnal hypoglycemia at endpoint. In addition, the effects on glycemic control of both treatments were investigated. METHODS AND RESULTS: Patients (489) previously on neutral protamine Hagedorn (NPH) insulin or GLAR plus RHI/LIS were switched to, or continued on GLA (target fasting blood glucose [FBG]=5.0-6.7 mmol/L [90-120 mg/dL]) for 8 weeks (qualification phase) prior to randomization; patients continued with their previous bolus insulin. Patients (n=395) were then randomized to LIS (n=193) or RHI (n=202) and treated for 16 weeks. The proportion of patients experiencing severe nocturnal hypoglycemia at the end of the study was 1.55% (n=3) in the RHI group and 1.11% (n=2) in the LIS group (p=0.938 between groups); the mean difference was 0.44% (95% CI: -1.77, 2.21), suggesting non-inferiority of RHI versus LIS. At the end of the study, both treatments did not differ with respect to glycemic control, as measured by hemoglobin A(1c) and FBG. CONCLUSION: These results suggest that GLA+LIS and GLA+RHI treatments were associated with a similar and low rate of severe nocturnal hypoglycemia. Further studies with greater patient sizes are necessary to verify the findings from the current study.

Determination of benzodiazepines in pericardial fluid by gas chromatography-mass spectrometry.

In Forensic Toxicology it is sometimes impossible to obtain a valid blood sample to perform toxicological analysis due to several factors like advanced state of decomposition, severe burns, bleed to death…. Pericardial Fluid has already been studied during the last years and has been proposed as a valid specimen for toxicological tests. Over the years, the consumption of benzodiazepines spread among the drug dependent population and became noticeable in drug facilitated assault cases and road accidents. Improvement of the analytical methodology required for detecting the presence of these drugs in biological samples is of great importance for forensic toxicology, in order to correctly diagnose an exposure or a poisoning. In this study, 9 benzodiazepines (diazepam, nordiazepam, midazolam, bromazepam, oxazepam, temazepam, lorazepam, clonazepam and alprazolam) have been determined in pericardial fluid. For this purpose a solid phase extraction (SPE) was carried out using Bond Elut Certify cartridges. After the derivatization of six of the nine benzodiazepines, gas chromatography coupled to a selective mass detector was used as the technique for the separation of the analytes. The method developed was fully validated for the 9 analytes and was applied to real samples of pericardial fluid received at the Forensic Toxicology Service of the University of Santiago de Compostela. Finally, they were compared with blood results looking for the existence of a possible correlation between both biological samples.

Role of hepatic autoregulation in defense against hypoglycemia in humans.

To assess the role of hepatic autoregulation in defense against hypoglycemia, we compared the effects of complete blockade of glucose counterregulation with those of blockade of only neurohumoral counterregulation during moderate (approximately 50 mg/dl) and severe (approximately 30 mg/dl) hypoglycemia induced by physiologic hyperinsulinemia during subcutaneous infusion of insulin in normal volunteers. Compared with observations in control experiments, neurohumoral counterregulatory blockade (somatostatin, propranolol, phentolamine, and metyrapone), during which identical moderate hypoglycemia was achieved using the glucose clamp technique, resulted in suppressed glucose production (0.62 +/- 0.08 vs. 1.56 +/- 0.07 mg/kg per min at 12 h, P less than 0.01) and augmented glucose utilization (2.17 +/- 0.18 vs. 1.57 +/- 0.07 mg/kg per min at 12 h, P less than 0.01). Complete blockade of counterregulation (neurohumoral blockade plus prevention of hypoglycemia) did not further enhance the suppressive effects of insulin on glucose production. However, when severe hypoglycemia was induced during neurohumoral counterregulatory blockade, glucose production was nearly two times greater (1.05 +/- 0.05 mg/kg per min at 9 h) than that observed during complete counterregulatory blockade (0.58 +/- 0.08 mg/kg per min at 9 h, P less than 0.01) and that observed during mere neurohumoral blockade with moderate hypoglycemia (0.59 +/- 0.06 mg/kg per min at 9 h, P less than 0.01). These results demonstrate that glucose counterregulation involves both neurohumoral and hepatic autoregulatory components: neurohumoral factors, which require only moderate hypoglycemia for their activation, augment glucose production and reduce glucose utilization; hepatic autoregulation requires severe hypoglycemia for its activation and may thus serve as an emergency system to protect the brain when other counterregulatory factors fail to prevent threatening hypoglycemia.

Mechanisms of glucagon secretion during insulin-induced hypoglycemia in man. Role of the beta cell and arterial hyperinsulinemia.

To elucidate the mechanisms controlling the response of glucagon to hypoglycemia, a vital component of the counterregulatory hormonal response, the role of intraislet insulin was studied in seven normal subjects and five subjects with insulin-dependent diabetes mellitus (IDDM) (of less than 15-mo duration). In the normal subjects, hypoglycemia (arterial plasma glucose [PG] 53 +/- 3 mg/dl) induced by an intravenous insulin infusion (30 mU/m2 X min for 1 h, free immunoreactive insulin [FIRI] 58 +/- 2 microU/ml) elicited a 100% fall in insulin secretion and an integrated rise in glucagon of 7.5 ng/ml per 120 min. When endogenous insulin secretion was suppressed by congruent to 50 or congruent to 85% by a hyperinsulinemic-euglycemic clamp (FIRI 63 +/- 1.5 or 147 +/- 0.3 microU/ml, respectively) before hypoglycemia, the alpha cell responses to hypoglycemia were identical to those of the control study. When the endogenous insulin secretion was stimulated by congruent to 100% (hyperinsulinemic-hyperglycemic clamp, FIRI 145 +/- 1.5 microU/ml, PG 132 +/- 2 mg/dl) before hypoglycemia, the alpha cell responses to the hypoglycemia were also superimposable on those of the control study. Finally, in C-peptide negative diabetic subjects made euglycemic by a continuous overnight intravenous insulin infusion, the alpha cell responses to hypoglycemia were comparable to those of normal subjects despite absent beta cell secretion, and were not affected by antecedent hyperinsulinemia (hyperinsulinemic-euglycemic clamp for 2 h, FIRI 61 +/- 2 microU/ml). These results indicate that the glucagon response to insulin-induced hypoglycemia is independent of the level of both endogenous intraislet and exogenous arterial insulin concentration in normal man, and that this response may be normal in the absence of endogenous insulin secretion, in contrast to earlier reports. Thus, loss of beta cell function is not responsible for alpha cell failure during insulin-induced hypoglycemia in IDDM.

Adrenergic mechanisms contribute to the late phase of hypoglycemic glucose counterregulation in humans by stimulating lipolysis.

Three studies were performed on nine normal volunteers to assess whether catecholamine-mediated lipolysis contributes to counterregulation to hypoglycemia. In these three studies, insulin was intravenously infused for 8 h (0.30 mU.kg-1.min-1 from 0 to 180 min, and 0.40 mU.kg-1.min-1 until 480 min). In study I (control study), only insulin was infused; in study II (direct + indirect effects of catecholamines), propranolol and phentolamine were superimposed to insulin and exogenous glucose was infused to reproduce the same plasma glucose (PG) concentration of study I. Study III (indirect effect of catecholamines) was the same as study II, except heparin (0.2 U.kg-1.min-1 after 80 min), 10% Intralipid (1 ml.min-1 after 160 min) and variable glucose to match PG of study II, were also infused. Glucose production (HGO), glucose utilization (Rd) [3-3H]glucose, and glucose oxidation and lipid oxidation (LO) (indirect calorimetry) were determined. In all three studies, PG decreased from approximately 4.8 to approximately 2.9 mmol/liter (P = NS between studies), and plasma glycerol and FFA decreased to a nadir at 120 min. Afterwards, in study I plasma glycerol and FFA increased by approximately 75% at 480 min, but in study II they remained approximately 40% lower than in study I, whereas in study III they rebounded as in study I (P = NS). In study II, LO was lower than in study I (1.69 +/- 0.13 vs. 3.53 +/- 0.19 mumol.kg-1.min-1, P less than 0.05); HGO was also lower between 60 and 480 min (7.48 +/- 0.57 vs. 11.6 +/- 0.35 mumol.kg-1.min-1, P less than 0.05), whereas Rd was greater between 210 and 480 min (19 +/- 0.38 vs. 11.4 +/- 0.34 mumol.kg-1.min-1, respectively, P less than 0.05). In study III, LO increased to the values of study I; between 4 and 8 h, HGO increased by approximately 2.5 mumol.kg-1.min-1, and Rd decreased by approximately 7 mumol.kg-1.min-1 vs. study II. We conclude that, in a late phase of hypoglycemia, the indirect effects of catecholamines (lipolysis mediated) account for at least approximately 50% of the adrenergic contribution to increased HGO, and approximately 85% of suppressed Rd.

Modest decrements in plasma glucose concentration cause early impairment in cognitive function and later activation of glucose counterregulation in the absence of hypoglycemic symptoms in normal man.

To establish the glycemic threshold for onset of neuroglycopenia (impaired cognitive function, measured by the latency of the P300 wave), activation of hormonal counterregulation and hypoglycemic symptoms, 12 normal subjects were studied either under conditions of insulin-induced, glucose-controlled plasma glucose decrements, or during maintenance of euglycemia. A decrement in plasma glucose concentration from 88 +/- 3 to 80 +/- 1 mg/dl for 150 min did not result in changes in the latency of the P300 wave nor in an activation of counterregulatory hormonal response. In contrast, a greater decrement in plasma glucose concentration from 87 +/- 3 to 72 +/- 1 mg/dl for 120 min caused an increase in the latency of the P300 wave (from 301 +/- 12 to 348 +/- 20 ms, P less than 0.01), a subsequent increase in all counterregulatory hormones but no hypoglycemic symptoms. Finally, when plasma glucose concentration was decreased in a stepwise manner from 88 +/- 2 to 50 +/- 1 mg/dl within 75 min, the increase in the latency of the P300 wave was correlated with the corresponding plasma glucose concentration (r = -0.76, P less than 0.001). The glycemic threshold for hypoglycemic symptoms was 49 +/- 2 mg/dl. Thus, in normal man the glycemic threshold for neuroglycopenia (72 +/- 1 mg/dl) is greater than currently thought; the hormonal counterregulation follows the onset of neuroglycopenia; the hypoglycemic symptoms are a late indicator of advanced neuroglycopenia.

Demonstration of a critical role for free fatty acids in mediating counterregulatory stimulation of gluconeogenesis and suppression of glucose utilization in humans.

In vitro studies indicate that FFA compete with glucose as an oxidative fuel in muscle and, in addition, stimulate gluconeogenesis in liver. During counterregulation of hypoglycemia, plasma FFA increase and this is associated with an increase in glucose production and a suppression of glucose utilization. To test the hypothesis that FFA mediate changes in glucose metabolism that occur during counterregulation, we examined the effects of acipimox, an inhibitor of lipolysis, on glucose production and utilization ([3-3H]glucose), and incorporation of [U-14C]-alanine into glucose during insulin-induced hypoglycemia. Eight normal volunteers were infused with insulin for 8 h to produce modest hypoglycemia (approximately 3 mM) on two occasions, first without acipimox (control) and then with acipimox administration (250 mg per os at 60 and 240 min). Despite identical plasma insulin concentrations, glucose had to be infused in the acipimox experiments (glucose-clamp technique) to maintain plasma glucose concentrations identical to those in control experiments. Acipimox completely prevented counterregulatory increases in lipolysis so that during the last 4 h plasma FFA were below baseline values and averaged 67 +/- 13 vs. 725 +/- 65 microM in control experiments, P < 0.001. Concomitantly, overall glucose production was reduced by 40% (5.5 +/- 11 vs. 9.3 +/- 0.7 mumol/kg per min, P < 0.001), and gluconeogenesis from alanine was reduced by nearly 70% (0.32 +/- 0.09 vs. 1.00 +/- 0.18 mumol/kg per min, P < 0.001), while glucose utilization increased by 15% (10.8 +/- 1.4 vs. 9.3 +/- 0.7 mumol/kg per min). We conclude that FFA play a critical role in mediating changes in glucose metabolism during counterregulation, and that under these conditions, FFA exert a much more profound effect on hepatic glucose production than on glucose utilization.

Ethanol impairs post-prandial hepatic protein metabolism.

The effects of acute ethanol ingestion on whole body and hepatic protein metabolism in humans are not known. To simulate social drinking, we compared the effects of the association of a mixed meal (632 kcal, 17% amino acids, 50% glucose, 33% lipids) with a bottle of either table wine (ethanol content 71 g) or water on the estimates ([1-14C]-leucine infusion) of whole body protein breakdown, oxidation, and synthesis, and on the intravascular fractional secretory rates (FSR) of hepatically (albumin, fibrinogen) and extrahepatically (IgG) synthesized plasma proteins in two randomized groups (ethanol n = 7, water n = 7) of healthy nonalcoholic volunteers. Each study was carried out for 8 h. Protein kinetics were measured in the overnight post-absorptive state, over the first 4 h, and during a meal infusion (via a nasogastric feeding tube at constant rate) combined with the oral ingestion of wine or water, over the last 4 h. When compared with water, wine ingestion during the meal reduced (P < 0.03) by 24% the rate of leucine oxidation, did not modify the estimates of whole body protein breakdown and synthesis, reduced (P < 0.01) by approximately 30% the FSR of albumin and fibrinogen, but did not affect IgG FSR. In conclusion, 70 g of ethanol, an amount usual among social drinkers, impairs hepatic protein metabolism. The habitual consumption of such amounts by reducing the synthesis and/or secretion of hepatic proteins might lead to the progressive development of liver injury and to hypoalbuminemia also in the absence of protein malnutrition.

Effects of simulated microgravity on the morphology and function of neonatal porcine cell clusters cultured with and without Sertoli cells.

Human islet allografts are well known to induce full and sustained remission of hyperglycemia, with complete normalization of key metabolic parameters. Nevertheless, acquiring human islets, even from cadaveric human donor pancreases, remains a significant impediment to successful transplantation therapy for diabetes. To overcome this difficulty, neonatal porcine cell clusters (NPCCs) have been considered for human islet substitutes because they are easily obtained by collagenase digestion of the neonatal piglet pancreas. Currently, the major hurdle in using NPCCs for xenograft is the delay (time lag) in achieving the posttransplant normalization of blood glucose levels in animal diabetic recipients. The present work is the first attempt to evaluate whether incubation of NPCCs in simulated microgravity, in the presence or absence of Sertoli cells (SC), may reduce the maturation time lag of beta-cells by differentiation acceleration in vitro, thereby expediting production, viability, and acquisition of functional competence of pretransplantation beta-cell-enriched islets. Following a 3-day incubation period, NPCCs maintained in conventional culture, NPCCs incubated in simulated microgravity in the HARV biochamber, and NPCCs plus co-incubated SC in simulated microgravity were examined for viability, morphology, and insulin secretion. Results show that NPCCs grown alone in the HARV biochamber are superior in quality, both in terms of viability and functional competence, when compared to other culture pretreatment protocols. This finding strongly suggests that NPCC pretreatment in simulated microgravity may enhance the transplantation success of NPCCs in the diabetic recipient.

Standard technical procedures for microencapsulation of human islets for graft into nonimmunosuppressed patients with type 1 diabetes mellitus.

To comply with regulatory restrictions, with regard to graft of human islets immunoprotected within artificial microcapsules, into patients with type 1 diabetes mellitus (T1DM) with no recipient immunosuppression, we have prepared standard protocols on: (1) sodium alginate purification (clinical grade) for microcapsule fabrication; (2) preparation of biocompatible and permselective microcapsules containing human islets; and (3) minimally invasive techniques for grafting of the encapsulated human islets into the recipients' peritoneal cavity. As to no. 1, starting from pharmaceutical grade, raw sodium alginate powder, we prepared a pyrogen- and endotoxin-free 1.6% alginate solution by means of dialysis, multiple filtrations, and dilution/osmolality adjustments. As to no. 2, we have selected human islet preparations associated with >80% purity/viability, which underwent careful functional quality control testing prior to encapsulation; namely, most capsules contained one islet. As for no. 3, we have devised a simple intraperitoneal injection method under abdominal echography guidance with only local anesthesia to deposit the encapsulated islets in saline within the peritoneal leaflets. These technical protocols were officially approved by the Italian Ministry of Health which has released permission to conduct a phase I, closed human trial in 10 patients using encapsulated human islet grafts into nonimmunosuppressed patients with T1DM.

Circulating insulin and insulin growth factor-1 are independent determinants of left ventricular mass and geometry in essential hypertension.

BACKGROUND: It is unclear whether insulin and insulin-like growth factor-1 (IGF-1) are independent determinants of left ventricular (LV) mass in essential hypertension. METHODS AND RESULTS: We studied 101 never-treated nondiabetic subjects with essential hypertension. All had 24-hour noninvasive ambulatory blood pressure (ABP) monitoring and a 75-g oral glucose tolerance test. We determined fasting glucose, insulin, and IGF-1 and postload glucose and insulin 2 hours after glucose. Insulin resistance was estimated by the homeostasis model assessment (HOMA(IR)) formula. LV mass showed an association with body mass index (BMI) (r=0.47; P<0.01), postload insulin (r=0.54; P<0.01), HOMA(IR) (r=0.39; P<0.01), and IGF-1 (r=0. 43; P<0.01) and a weaker association with average 24-hour systolic and diastolic ABPs (r=0.29 and r=0.26; P<0.05) and basal insulin (r=0.31; P<0.05). Relative wall thickness was positively related to IGF-1 (r=0.39; P<0.01) but not to fasting or 2-hour postload insulin, HOMA(IR), and glucose. In a multiple regression analysis, the final LV mass model (R(2)=0.64) included IGF-1, postload insulin, average 24-hour systolic ABP, sex, and BMI. IGF-1 and postload insulin accounted for >40% of variability of LV mass. The final model (R(2)=0.36) for relative wall thickness included IGF-1 (16% total explained variability), average 24-hour systolic ABP, sex, BMI, and age but not insulin and HOMA(IR). CONCLUSIONS: These data indicate that insulin and IGF-1 are powerful independent determinants of LV mass and geometry in untreated subjects with essential hypertension and normal glucose tolerance.

Effects of recent, short-term hyperglycemia on responses to hypoglycemia in humans. Relevance to the pathogenesis of hypoglycemia unawareness and hyperglycemia-induced insulin resistance.

A single episode of recent hypoglycemia increases, whereas long-term hyperglycemia decreases, the glycemic thresholds of responses of counterregulatory hormone and symptoms to subsequent hypoglycemia in humans. To assess whether short-term, antecedent hyperglycemia exerts effects opposite to those observed after acute hypoglycemia, seven normal, nondiabetic subjects and eight insulin-dependent diabetes mellitus (IDDM) patients were studied during hyperinsulinemic-hypoglycemic clamp (sequential, 90-min plateaus of plasma glucose [PG] of 4.3, 3.7, 3.0, and 2.4 mmol/l). Nondiabetic subjects were studied the morning after either 6-h clamped hyperglycemia (PG approximately 13.5 mmol/l) or euglycemia (PG approximately 5 mmol/l) between 1600 and 2200 the previous day (glucose and insulin infused on both occasions), as well as after nocturnal hyperglycemia (PG approximately 13.5 mmol/l) or euglycemia between 2300 and 0500. The IDDM patients were studied after 15 h of euglycemia or hyperglycemia (approximately 17 mmol/l) but identical hyperinsulinemia (approximately 225 pmol/l) between 1600 and 0700. Neither PG thresholds of counterregulatory hormone, symptoms, onset of cognitive dysfunction to hypoglycemia, nor maximal responses were affected by antecedent, short-term hyperglycemia in normal nondiabetic subjects and IDDM patients (NS). However, the rate of glucose infusion required to maintain hypoglycemic plateaus during hypoglycemia was lower after hyperglycemia (nondiabetic subjects 31.2 +/- 3.4 vs. 36.7 +/- 4 mumol.kg-1.min-1, IDDM patients 33 +/- 3.1 vs. 42.5 +/- 3.9 mumol.kg-1.min-1; P < 0.05) indicating greater insulin resistance induced by antecedent hyperglycemia. In conclusion, in contrast to acute hypoglycemia and long-term hyperglycemia, recent, short-term hyperglycemia does not affect physiological responses to hypoglycemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Important role of adrenergic mechanisms in acute glucose counterregulation following insulin-induced hypoglycemia in type I diabetes. Evidence for an effect mediated by beta-adrenoreceptors.

UNLABELLED: During hypoglycemia induced by an i.v. insulin infusion for 60 min, rates of plasma glucose (PG) decrease and recovery, PG nadir, and plasma counter-regulatory hormone and free fatty acid responses were studied in eight type I uncomplicated diabetic subjects and eight nondiabetic subjects. Each subject was tested three times at two different rates of insulin infusion (25 and 32 mU/m2/min): (1) during infusion of saline, (2) during infusion of phentolamine + propranolol (combined alpha, beta-blockade), and (3) during infusion of propranolol alone (isolated beta-blockade) for 150 min. At the time of the studies, the diabetic subjects had been made euglycemic by an overnight i.v. insulin infusion. During infusion of insulin (25 mU/m2/min) and saline, the rates of PG decrease and recovery were slower (P less than 0.01) and PG nadir was delayed in the diabetic subjects. Moreover, their plasma glucagon response was blunted while plasma epinephrine, norepinephrine, growth hormone, and cortisol responses were similar in both groups. Infusion of insulin at 32 mU/m2/min caused larger decreases in PG than had been observed when insulin was infused at 25 mU/m2/min. Plasma glucagon responses increased in the nondiabetic subjects (P less than 0.05) but not in the diabetic subjects. However, in the diabetic subjects, plasma epinephrine increased more than in the nondiabetic subjects (P less than 0.05). There was an inverse correlation between the individual plasma epinephrine responses and the plasma glucagon responses in the diabetic subjects (r = -0.72) but not in the nondiabetic subjects. Alpha, beta-adrenergic blockade decreased the plasma glucose nadir and impaired the rate at which normoglycemia was restored in the diabetic subjects (P less than 0.005 vs. saline) but not in the nondiabetic subjects. Plasma catecholamine and growth hormone responses were increased and plasma FFA recovery was suppressed in both groups (P less than 0.05 vs. saline), while the cortisol responses were unaltered. During isolated beta-adrenergic blockade, changes in plasma glucose, counterregulatory hormones and FFA were essentially identical to those observed during combined alpha, beta-adrenergic blockade in both groups except that the augmented plasma norepinephrine responses were no longer apparent. CONCLUSIONS: although epinephrine is not essential for prompt restoration of normoglycemia in normal man following insulin-induced hypoglycemia, it plays a major role in glucose counterregulation in diabetics who have an impaired glucagon secretion in response to hypoglycemia. These counterregulatory effects of epinephrine are mediated by beta-adrenoreceptors.

HbA1 in subjects with abnormal glucose tolerance but normal fasting plasma glucose.

HbA1(a+b+c)(HbA1) was determined chromatographically in 107 subjects with normal fasting plasma glucose (FPG) and 112 patients with overt diabetes. Subjects with normal FPG were divided into two groups based on their response to two oral glucose tolerance tests (OGTTs), at an interval of 2 mo. In 40 subjects with normal OGTT (group I), HbA1 ranged from 5.2% to 7.2%, while in 67 subjects with abnormal OGTT (group II), it ranged from 6.3% to 9.6%. HbA1 levels were significantly higher in group II than in group I (7.7 +/- 0.09% versus 6.4 +/- 0.08%, mean +/- SEM, P less than 0.0005), but 14 subjects of group II had HbA1 levels less than 7.2%. No correlation was found between HbA1 and FPG, OGTT peak, and curve area in either group. However, the correlation became significant in all 107 subjects with normal FPG (groups I + II). In patients with overt diabetes, HbA1 ranged from 6.3% to 18% (11.9 +/- 0.22%) and correlated with FPG (r = 0.78, P less than 0.0005). The traditional OGTT seems more sensitive than the HbA1 measurement in detecting subjects with reduced carbohydrate tolerance. HbA1 level, on the other hand, is known to be more specific indicator of structural abnormalities following long-term hyperglycemia. Thus HbA1 determination might be a helpful test along with OGTT to improve both selection and follow-up subjects with true borderline diabetes.

Comparison of glucose counterregulation during short-term and prolonged hypoglycemia in normal humans.

To compare glucose counterregulatory mechanisms during short-term hypoglycemia and prolonged hypoglycemia, insulin was infused either intravenously (160 mU X M-2 X min) for 10 min or subcutaneously (15 mU X M-2 X min) for 12 h in normal volunteers. With each type of insulin infusion, hypoglycemia (approximately 50 mg/dl) was either allowed to develop or was prevented (control experiments) by the glucose-clamp technique. During prolonged hypoglycemia, both increased glucose production (1.55 +/- 0.05 versus 0.33 +/- 0.14 mg X kg-1 X min in control experiments at 12 h, P less than 0.01) and suppressed glucose utilization (1.55 +/- 0.06 versus 3.17 +/- 0.15 mg X kg-1 X min in control studies at 12 h, P less than 0.01) were involved in counterregulation. During short-term hypoglycemia, only increased glucose production (3.23 +/- 0.33 versus 0.06 +/- 0.03 mg X kg-1 X min in control experiments at 60 min) was involved, since glucose clearance actually increased (3.99 +/- 0.20 versus 2.88 +/- 0.02 ml X kg-1 X min in control experiments at 60 min, P less than 0.01). Estimated portal venous insulin concentrations decreased 40% (basal 24 +/- 3 versus 14 +/- 1 mU/ml at 60 min, P less than 0.01) in the short-term hypoglycemia experiments but remained at basal levels (basal 25 +/- 1 versus approximately 26 microU/min between 1 and 12 h) during prolonged hypoglycemia. Despite the fact that hypoglycemia was more gradually induced in the prolonged hypoglycemia model, peak counterregulatory hormone responses were at least as great as those during short-term hypoglycemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormal glucose counterregulation in insulin-dependent diabetes mellitus. Interaction of anti-insulin antibodies and impaired glucagon and epinephrine secretion.

To evaluate the roles of counterregulatory hormones and insulin antibodies in the impairment of plasma glucose recovery from hypoglycemia in diabetes mellitus, and to assess the relationship between the glucagon response and duration of the disease, 21 insulin-dependent diabetic patients and 10 nondiabetic subjects were studied. The diabetics consisted of 5 patients with recent onset of diabetes (less than 1 mo); 11 with 2.6 +/- 0.3 (mean +/- SEM) yr duration of diabetes, 5 of whom had insulin antibodies; and 5 patients with long-term diabetes (21 +/- 3 yr), insulin antibodies, and autonomic neuropathy. During insulin-induced hypoglycemia (28 mU/m2 X min for 60 min) in patients with recent-onset diabetes, plasma free insulin, glucose, and counterregulatory hormone concentrations did not differ from those of nondiabetic subjects. In patients with insulin antibodies, the disappearance of insulin after insulin infusion was delayed, and both restitution of normoglycemia and plasma glucagon response were blunted compared with patients without antibodies. When glucagon was infused (80-130 ng/m2 X min) during hypoglycemia in diabetics with impaired glucagon responses in order to simulate normal glucagon responses, plasma glucose recovery was normalized in patients without antibodies but not in those with antibodies. In patients with long-standing diabetes, restitution of normoglycemia was further impaired and this was associated with an absent plasma glucagon response and a diminished plasma epinephrine response. Plasma glucagon responses to hypoglycemia were inversely correlated to the duration of diabetes (r = -0.943; P less than 0.0005). It is concluded that impaired A-cell secretion is the predominant mechanism for the delayed glucose recovery after hypoglycemia in diabetic patients without insulin antibodies and normal epinephrine responses. Slowed disappearance of insulin due to the presence of insulin antibodies further delays the restoration of normoglycemia. Patients with long-standing diabetes and autonomic neuropathy exhibit decreased epinephrine secretion, which leads to an additional retardation of glucose recovery. Since plasma glucagon and epinephrine responses to hypoglycemia were normal at the onset of diabetes but diminished in long-term diabetes, it appears that the impaired glucagon and epinephrine responses to hypoglycemia are acquired defects that develop subsequent to B-cell failure.