Case report: Gastroenterological management in a case of cardio-facio-cutaneous syndrome.

Background: cardio-facio-cutaneous syndrome is a rare genetic disorder affecting less than 900 people in the world. It is mainly characterized by craniofacial, dermatologic and cardiac defects, but also gastroenterological symptoms may be present, ranging from feeding difficulties to gastroesophageal reflux and constipation.In this report we describe a case of this syndrome characterized by severe feeding and growth difficulties, with a particular focus on the management of gastroenterological complications. Case presentation: the patient was a caucasian male affected by Cardio-Facio-Cutaneous syndrome who presented feeding difficulties already a few hours after birth. These symptoms worsened in the following months and lead to a complete growth arrest and malnutrition. He was first treated with a nasogastric tube placement. Subsequently, a laparoscopic Nissen fundoplication and a laparoscopic Stamm gastrostomy were performed. The child was fed with nocturnal enteral nutrition and diurnal oral and enteral nutrition. Eventually the patient resumed feeding validly and regained adequate growth. Conclusion: this paper aims to bring to light a complex rare syndrome that infrequently comes to the attention of the pediatricians and whose diagnosis is not always straightforward. We also highlight the possible complications under a gastroenterologic point of view. Our contribution can be helpful to the pediatrician in the first diagnostic suspect of this syndrome. In particular, it is worth highlighting that -in an infant with Noonan-like features- symptoms like suction or swallowing problems, vomiting and feeding difficulties should orient towards the diagnosis of a Cardio-facio-cutaneous syndrome. It is also important to stress that its related gastroenterological issues may lead to severe growth failure and therefore the role of the gastroenterologist is key to manage supplemental feeding and to establish whether a nasogastric or gastrostomic tube placement is necessary.

Not only for caregivers: intranasal glucagon for severe hypoglycaemia in a simulation study.

AIMS: To evaluate: (i) the propensity of paediatrics and emergency medicine residents to select different therapeutic options and (ii) the speed and administration success in a high-fidelity simulation of severe hypoglycaemia in a child with type 1 diabetes (T1DM). METHODS: In this single-centre high-fidelity simulation study, 51 paediatrics or emergency medicine residents were exposed to a scenario of severe hypoglycaemia in a T1DM child attending an ambulatory setting, before and after a training on the preparation and administration of both injectable and IN glucagon. Time for drug delivery and its effectiveness were collected. RESULTS: Before training, 45.1% of participants chose to administer injectable glucagon, 43.1% intravenous glucose solution, 5.9% intranasal (IN) glucagon, and 5.9% took no action. Administration was successful in 74% of injectable glucagon, 33.3% intravenous glucose solution, and 22.7% IN glucagon. After training, 58.8% of participants chose IN and 41.2% injectable glucagon, with 100% of successful administrations for IN glucagon and 90.5% for injectable glucagon. Time to successful administration was shorter for IN than injectable glucagon (23 ± 10 vs. 38 ± 7 s, p < 0.0001). CONCLUSIONS: IN glucagon is an easy and effective option for severe hypoglycaemia treatment, with an almost zero possibility of failure provided that adequate training is imparted.

The use of real time continuous glucose monitoring or flash glucose monitoring in the management of diabetes: A consensus view of Italian diabetes experts using the Delphi method.

Until recently, in Italy, the use of continuous glucose monitoring (CGM) systems has been limited, but is now rapidly increasing, including the so-called real-time CGM (rtCGM) and the intermittently viewed CGM (iCGM), also called Flash Glucose Monitoring (FGM). These technologies overcome many of the limitations of self-monitoring of blood glucose (SMBG) by fingerprick and allow to go beyond HbA1c to check glucose control in diabetes. However, standardized protocols for applying and interpreting rtCGM and FGM data are lacking. In this paper, we delineate a consensus amongst Italian diabetes physicians on the attributes of rtCGM and FGM technologies, and introduce a consistent approach for their use by Italian healthcare professionals. Most experts consider rtCGM and FGM as two separate categories of interstitial subcutaneous fluid (ISF) sensing technologies, and see them as superior to SMBG. Furthermore, there is strong consensus that rtCGM and FGM reduce hypoglycemia risk, increase the amount of time in the target glucose range and augment treatment satisfaction. However, there is still no agreement on the indication of the FGM for subjects who suffer asymptomatic hypoglycemia. Consensus on the role of education in initiating and optimizing use of rtCGM/FGM and about the interpretation of glucose trends was near unanimous, whereas no consensus was reached on the statement that there are no disadvantages/risks of rtCGM/FGM. Some issues remain in rtCGM/FGM management: a) risk of excessive correction of high or low glucose; b) risk of alert fatigue leading to alert silencing or rtCGM termination; c) allergic reaction to the adhesive keeping rtCGM or FGM sensors in place. The panel almost unanimously agreed that sensor accuracy depends on multiple variables, that alarm setting should be individualized, and that global glycemic profile represent an useful tool in interpreting glucose data. More clinical studies and a wider use of these devices will increase the efficacy and effectiveness of continuous glucose monitoring in Italy.

Parental evaluation of a telemonitoring service for children with Type 1 Diabetes.

Introduction In the past years, we developed a telemonitoring service for young patients affected by Type 1 Diabetes. The service provides data to the clinical staff and offers an important tool to the parents, that are able to oversee in real time their children. The aim of this work was to analyze the parents' perceived usefulness of the service. Methods The service was tested by the parents of 31 children enrolled in a seven-day clinical trial during a summer camp. To study the parents' perception we proposed and analyzed two questionnaires. A baseline questionnaire focused on the daily management and implications of their children's diabetes, while a post-study one measured the perceived benefits of telemonitoring. Questionnaires also included free text comment spaces. Results Analysis of the baseline questionnaires underlined the parents' suffering and fatigue: 51% of total responses showed a negative tendency and the mean value of the perceived quality of life was 64.13 in a 0-100 scale. In the post-study questionnaires about half of the parents believed in a possible improvement adopting telemonitoring. Moreover, the foreseen improvement in quality of life was significant, increasing from 64.13 to 78.39 ( p-value = 0.0001). The analysis of free text comments highlighted an improvement in mood, and parents' commitment was also proved by their willingness to pay for the service (median = 200 euro/year). Discussion A high number of parents appreciated the telemonitoring service and were confident that it could improve communication with physicians as well as the family's own peace of mind.

Insulin pump failures in Italian children with Type 1 diabetes: retrospective 1-year cohort study.

AIMS: Insulin pump failure and/or malfunction requiring replacement have not been thoroughly investigated. This study evaluated pump replacement in children and adolescents with Type 1 diabetes using insulin pump therapy. METHODS: Data were collected for all participants younger than 19 years, starting insulin pump therapy before 31 December 2013. For each child, age, disease duration, date of insulin pump therapy initiation, insulin pump model, failure/malfunction/replacement yes/no and reason were considered for the year 2013. RESULTS: Data were returned by 40 of 43 paediatric centres belonging to the Diabetes Study Group of the Italian Society of Paediatric Endocrinology and Diabetology. In total, 1574 of 11 311 (13.9%) children and adolescents with Type 1 diabetes were using an insulin pump: 29.2% Animas VIBE™ , 9.4% Medtronic MiniMed 715/515™ , 34.3% Medtronic MiniMed VEO™ , 24.3% Accu-Check Spirit Combo™ and 2.8% other models. In 2013, 0.165 insulin pump replacements per patient-year (11.8% due to pump failure/malfunction and 4.7% due to accidental damage) were recorded. Animas VIBE™ (22.1%) and Medtronic MiniMed VEO™ (17.7%) were the most replaced. CONCLUSIONS: In a large cohort of Italian children and adolescents with Type 1 diabetes, insulin pump failure/malfunction and consequent replacement are aligned with rates previously reported and higher in more sophisticated pump models.

Survey on the use of insulin pumps in Italy: comparison between pediatric and adult age groups (IMITA study).

AIMS: The aim of the study was to evaluate and compare continuous subcutaneous insulin infusion (CSII) use in pediatric and adult age groups. METHODS: Data were collected with a questionnaire sent by e-mail to CSII-experienced Diabetes Centers. The questionnaire assessed: (1) number of CSII-treated patients; (2) patient demographic data and characteristics; (3) structure and organization of Diabetes Centers providing CSII therapy; (4) pump characteristics (conventional pump, sensor-augmented pump); and (5) CSII dropouts. RESULTS: A total of 217 out of 1093 Italian centers participated: 51 pediatric (23.5 %) and 166 (76.5 %) adult centers (AP). Compared to a survey performed in 2005, there was a significant increase in the number of pediatric units when compared to adult units (112 vs 37 %, respectively, p < 0.05). Pediatric age is characterized by a greater concern for quality of life and injections, and a higher dropout rate (10.6 vs 8.9 %) mainly related to pump wearability and site reactions. A complete diabetes-care team is associated with a superior use of technology (fewer dropouts, increased CGM and advanced bolus use) which is, however, still used in a small percentage of patients. CONCLUSIONS: In Italy, the number of CSII-treated pediatric patients (PP) is growing more significantly when compared to adults. Only 60 % of all patients are using advanced functions and 20 % are using CGMs continuously. This confirms the great interest in diabetes technology that is growing in pediatric diabetologists. However, much improvement is warranted in the organization and specialized training of pediatric, adult and transitional facilities.

Health-related quality of life and treatment preferences in adolescents with type 1 diabetes. The VIPKIDS study.

A multi-centre, observational, cross-sectional study was carried out to determine whether the health-related quality of life (HRQOL) of adolescents with type 1 diabetes is affected by different insulin treatment systems, and which features of HRQOL are impacted by the respective insulin treatment. The study regarded 577 adolescents, aged 10-17 years, with type 1 diabetes treated with continuous subcutaneous insulin infusion (CSII) (n = 306) or multiple daily injections (MDI) (n = 271). The Insulin Delivery System Rating Questionnaire was validated in Italian and was self-completed by the subjects during a routine visit to the centres. Subjects were compared following the domains of the questionnaire. Good HRQOL was seen in subjects treated with either MDI or CSII. Significant differences were not found in the domains for general diabetes, including diabetes worries, social burden and psychological well-being. Multiple quantile regression analysis showed that CSII confers significant advantages in terms of HRQOL with improvements in treatment satisfaction, perceived clinical efficacy and reduction in treatment interference with daily activities. This favourable impact was more evident in subjects reporting lower HRQOL scores, suggesting that CSII may be especially useful for individuals perceiving a poor HRQOL. Analysis of the domains indicated that CSII was associated with a higher HRQOL than MDI. Life-course HRQOL evaluation using a standardised questionnaire can ensure better chronic disease management. This is particularly important when providing individualised care for adolescents, as they become increasingly responsible for managing their diabetes.

Prevalence, presentation and clinical evolution of Graves' disease in children and adolescents with type 1 diabetes mellitus.

AIMS: To ascertain the prevalence of Graves' disease (GD) in 1,323 Caucasian children with type 1 diabetes mellitus (T1DM), and to compare the course of GD in T1DM patients with the one observed in 109 Caucasian peer patients with GD but without T1DM (group B). RESULTS: Only 7 patients (0.53%) of the T1DM series also presented with GD (group A)which was diagnosed many years after diabetes presentation. At GD diagnosis, the prevalence of preclinical hyperthyroidism was higher in group A (p = 0.0001), whereas serum TSH receptor antibodies (TRABs) were higher in group B (p = 0.04). The subsequent course with methimazole therapy and after its withdrawal was very similar in both groups. CONCLUSIONS: GD prevalence in T1DM patients was 0.53%, i.e. almost identical to the one reported in the general population. GD was diagnosed many years after T1DM presentation. At GD diagnosis, the clinical picture was milder and TRAB serum levels were lower in diabetic patients. Preclinical diagnosis and early treatment of GD were not associated with better responsiveness to therapy. Screening programs based on periodical TRAB assessments are not useful in T1DM.

Impairment of cardiovascular autonomic pattern in obese adolescents with Type 2 diabetes mellitus.

UNLABELLED: The aim of this study was to assess the behaviour of insulin sensitivity and insulin resistance (IR) indexes in a group of obese adolescents with Type 2 diabetes mellitus (T2DM) in comparison to obese adolescents without diabetes and normal controls, moreover to compare these parameters with the cardiac autonomic pattern. Seven T2DM obese (12.7 ± 0.5 yr), 18 obese without T2DM, and 10 nonobese control adolescents age matched were studied. In all subjects we performed oral glucose tolerance test (OGTT) with insulin and glucose determination, 24-h electrocardiogram Holter, blood pressure monitoring, ecohocardiogram. RESULTS: serum lipids were significantly higher in obese and T2DM. Insulin sensitivity was significantly reduced in T2DM and obese vs controls; T2DM showed a more pronounced oral glucose insulin sensitivity (OGIS) reduction vs obese. Both obese and T2DM presented an higher IR. T2DM showed an impaired ß-cell function, with insulin areas under the curve and disposition index significantly reduced in comparison to controls and obese who showed similar values. A progressive reduction of vagal indexes and an increase of sympathetic indexes were found in obese adolescents and were more pronounced in T2DM. These parameters were correlated with OGIS and ß-cell function parameters in both obese and T2DM adolescents. T2DM showed a significant relative wall thickness increase suggesting a trend toward concentric remodeling. In conclusion, T2DM adolescents are characterized by a more marked IR reduced ß-cell function in comparison to non-diabetic obese. These modifications may lead to an early impairment of the autonomic pattern.

The incidence of type 1 diabetes is increasing in both children and young adults in Northern Italy: 1984-2004 temporal trends.

AIMS/HYPOTHESIS: A shift towards younger age at onset of diabetes in susceptible people has been suggested as a possible explanation for the increasing temporal trend in incidence of type 1 diabetes. We aimed to test this hypothesis by assessing trends in incidence rates in the period 1984-2004 in children and young adults in Northern Italy. METHODS: The study bases were: (1) children resident in the Province of Turin in the period 1984-2004 and in the remaining areas of the Piedmont Region in the period 1990-2004; and (2) young adults (15-29 years) resident in the Province of Turin in the period 1984-2003. Temporal trends in rates were analysed using Poisson regression models. RESULTS: A total of 1,773 incident cases were identified. Overall incidence rates/100,000 person-years in the age groups 0-14 and 15-29 years were 11.3 (95% CI 10.7-12.0) and 7.1 (95% CI 6.6-7.7), respectively, with sex differences among young adults only (incidence rate ratio [IRR] in males vs females 1.41 [95% CI 1.20-1.64]). Average annual increases in incidence rates were similar in children and young adults at 3.3% (95% CI 2.5-4.1). Compared with the period 1984-89, in 2000-2004 a 60% higher risk was found in both age 0-14 years (IRR 1.60, 95% CI 1.31-1.95) and 15-29 years (IRR 1.57, 95% CI 1.26-1.96) groups. The Poisson modelling showed no interaction between calendar period and age at onset. CONCLUSIONS/INTERPRETATION: Incidence of type 1 diabetes in Northern Italy is increasing over time in both children and young adults, not supporting the hypothesis of a shift towards younger age as the main explanation for the increasing temporal trend in children.

Establishing glycaemic control with continuous subcutaneous insulin infusion in children and adolescents with type 1 diabetes: experience of the PedPump Study in 17 countries.

AIMS/HYPOTHESIS: To assess the use of paediatric continuous subcutaneous infusion (CSII) under real-life conditions by analysing data recorded for up to 90 days and relating them to outcome. METHODS: Pump programming data from patients aged 0-18 years treated with CSII in 30 centres from 16 European countries and Israel were recorded during routine clinical visits. HbA(1c) was measured centrally. RESULTS: A total of 1,041 patients (age: 11.8 +/- 4.2 years; diabetes duration: 6.0 +/- 3.6 years; average CSII duration: 2.0 +/- 1.3 years; HbA(1c): 8.0 +/- 1.3% [means +/- SD]) participated. Glycaemic control was better in preschool (n = 142; 7.5 +/- 0.9%) and pre-adolescent (6-11 years, n = 321; 7.7 +/- 1.0%) children than in adolescent patients (12-18 years, n = 578; 8.3 +/- 1.4%). There was a significant negative correlation between HbA(1c) and daily bolus number, but not between HbA(1c) and total daily insulin dose. The use of <6.7 daily boluses was a significant predictor of an HbA(1c) level >7.5%. The incidence of severe hypoglycaemia and ketoacidosis was 6.63 and 6.26 events per 100 patient-years, respectively. CONCLUSIONS/INTERPRETATION: This large paediatric survey of CSII shows that glycaemic targets can be frequently achieved, particularly in young children, and the incidence of acute complications is low. Adequate substitution of basal and prandial insulin is associated with a better HbA(1c).

Intensive insulin therapy in preschool-aged diabetic children: from multiple daily injections to continuous subcutaneous insulin infusion through indwelling catheters.

In this study, glycemic control, diabetes care indices and quality of life (QoL) were assessed in 2 groups of newly diagnosed Type 1 diabetic subjects <6 yr old who were randomized to multiple daily injections with (Group A) or without (Group B) an indwelling catheter. Group A [12 males (M)/8 females (F), mean age 3.2+/-1.4 yr] and Group B (9M/11F, mean age 3.9+/-1.8 yr) were evaluated at baseline and after 6 and 12 months of treatment. No significant difference was observed in metabolic control (glycosylated hemoglobin) or in the number of hypoglycemic events between the groups. Patients in Group A had a greater number of daily insulin injections, monitored blood glucose more frequently and had a lower total daily insulin dose per kg (p<0.05). QoL was better in group A. At the end of the study 30% of group A patients progressed to continuous sc insulin infusion (CSII), while no child in Group B switched to a different insulin regimen. Based on these findings, indwelling catheter therapy may be helpful for selected CSII candidates.

Defective function of the Fas apoptotic pathway in type 1 diabetes mellitus correlates with age at onset.

The Fas death receptor triggers lymphocyte apoptosis through an extrinsic and an intrinsic pathway involving caspase-8 and -9 respectively. Inherited defects of Fas function are displayed by a proportion of patients with Type 1 diabetes mellitus (T1DM) especially those with a second autoimmunity (T1DM-p). This study assesses activation of both pathways in Fas-resistant (FasR) patients to localize the defect. 21/28 (75 percent) T1DM-p, 14/50 (38 percent) T1DM, and 7/150 (5 percent) controls were FasR. Analysis of the 35 FasR patients and 20 Fas-sensitive (FasS) controls showed that caspase-9 activity was lower in T1DM-p and T1DM than in controls, whereas caspase-8 activity was lower in T1DM-p than in T1DM and the controls. Single patient analysis showed that 16/35 patients displayed defective activity of one (FasR1), whereas 19 displayed normal activity of both caspases (FasR2). Ages at onset of diabetes mellitus in T1DM and the second autoimmune disease in T1DM-p were lower in FasR than in FasS patients. All FasR1 patients developed diabetes mellitus before the age of 9 years, whereas a later onset was displayed by 26% FasR2 and 53% FasS patients. These data show that defective Fas function may involve both the extrinsic and intrinsic pathway in T1DM and severity correlates with the precocity of the autoimmune attack and its tissue polyreactivity.

Age-related differences in metabolic response to continuous subcutaneous insulin infusion in pre-pubertal and pubertal children with Type 1 diabetes mellitus.

The aim of this study was to evaluate clinical and metabolic data in a cohort of Type 1 diabetes (T1DM) children before and after 2 yr of continuous s.c. insulin infusion (CSII). Forty seven T1DM patients were subdivided into two groups: Group A (20 pre-pubertal children, mean age 7.43+/-3.19 yr); Group B (27 pubertal adolescents, mean age 14.47+/-1.91 yr). No statistically significant differences in body mass index (BMI) occurred in either groups after starting CSII or during follow-up. The frequency of mild-hypoglycemias significantly declined during pump therapy only in Group A (p<0.05). Both pre-pubertal and pubertal patients required a significant reduction in their total insulin requirement after 12 and 24 months of CSII. The total percentage of daily insulin doses delivered as basal rates was similar in both groups and was negatively associated (beta=-2.956, p=0.05) with glycosylated hemoglobin (HbA1c) values. No significant correlation was found between the percentage of the basal insulin rate and the number of daily boluses. Differences in timing of the highest insulin requirement were observed between the two groups. Group A had a higher insulin basal rate late in the evening (20:00-24:00 h), while Group B had a higher insulin requirement early in the morning (03:00-07:00 h). The HbA1c levels significantly improved in Group A after 6-12 and 24 months of CSII. In Group B a reduction of HbA1c values was observed only after 6 months of pump therapy (p=0.05). CSII is an effective therapy for all ages but different metabolic requirements should also be taken into account.

Waist circumference as a predictor of cardiovascular and metabolic risk factors in obese girls.

OBJECTIVES: (a). to explore the relationship between waist circumference and certain cardiovascular risk factors in a group of girls; and (b). to assess the clinical relevance of waist circumference in identifying girls with higher cardiovascular risk across puberty. SUBJECTS AND METHODS: One-hundred and fifty-five overweight or obese girls aged 5-16 y were recruited. Overweight and obesity were defined on the basis of BMI, according to Cole. RESULTS: : Waist circumference was significantly correlated with plasma insulin (r=0.43; P<0.001), systolic blood pressure (r=0.22; P=0.007) and IR(HOMA) (r=0.40; P<0.001). A multivariate linear correlation analysis showed that, when adjusted for age and Tanner stage, waist circumference was significantly associated with plasma insulin (r(2)=0.23; P<0.01), IR(HOMA) (r(2)=0.17; P<0.02), systolic and diastolic blood pressure (r(2)=0.20; P=0.006 and r(2)=0.32; P<0.001, respectively). A logistic regression analysis, using IR(HOMA) as the dependent variable, showed that waist circumference was a significant independent risk factor of insulin resistance (IR(HOMA)>or=2.6) in this group of girls (OR 1.10; 95% CI 1.03-1.18; P=0.003), independently of their age and Tanner stage. CONCLUSIONS: Waist circumference of these girls was independently associated with certain cardiovascular risk factors, in particular insulin resistance and diastolic blood pressure, independently of age and Tanner stage. Thus suggesting that waist circumference may be reasonably included in clinical practice as a simple tool that may help to identify sub-groups of obese girls at higher metabolic risk across puberty.

Glutamic acid decarboxylase and ICA512/IA-2 autoantibodies as disease markers and relationship to residual beta-cell function and glycemic control in young type 1 diabetic patients.

Circulating autoantibodies (Ab) to islet autoantigens, glutamic acid decarboxylase (GAD(65)), and tyrosine phosphatase ICA512/IA-2 have been proposed as predictive markers of type 1 diabetes mellitus. To ascertain residual beta-cell function and the clinical relevance for monitoring autoimmunity after clinical manifestation of disease, we studied 63 children at diagnosis of type 1 diabetes (mean SD age 7.5 +/- 4 years) and 91 adolescent patients with type 1 diabetes (age 14.7 +/- 1.6 years) with a mean duration of disease of 7 +/- 3.5) years. Forty-two normal adolescent subjects (age 14.6 +/- 1.8 years) without a family history of diabetes were the control group. Anti-GAD(65) and ICA512/IA-2 Ab were assessed by a quantitative radioimmunoprecipitation assay. The relationship between humoral autoimmunity and clinical parameters was explored. GAD(65) and ICA512/IA-2 Ab were detected in 56% and 63% of newly diagnosed children and the prevalence was not different in relationship to clinical characteristics. Levels of GAD(65) Ab positively correlated with diagnosis age (P <.05). Both Ab were associated with islet cell antibodies (ICA) (P <.05), but one fifth of patients had at least 1 of the 2 Ab and absent ICA. At onset, only age showed a significant relationship to residual C-peptide secretion. Among the cohort of patients with diabetes of short-mid duration, GAD(65) and ICA512/IA-2 Ab were present in 44% and 45% of cases (P >.05 and P <.05 v newly diagnosed children, respectively) and more patients were identified by these Ab (68%) than by ICA alone (34%) (P <.05). In this cohort, levels of ICA512/IA-2 Ab negatively correlated with levels of glycosylated hemoglobin (HbA(1c)) (P <.005) and with daily insulin requirement (P <.05). Moreover, the presence of some residual C-peptide secretion was significantly associated with the presence of ICA512/IA-2 Ab (P <.05). Our findings confirm that positivity for either GAD(65) or ICA512/IA-2 Ab is a highly sensitive marker of type 1 diabetes in the pediatric age group, identifying a group of patients with absent ICA immunofluorescence. The persistence of Ab to islet tyrosine phosphatase possibly represents a marker of better glycemic control and less insulin requirement, indicating residual beta-cell function, thus conferring clinical and prognostic relevance to these Ab, as well as potential usefulness in intervention strategies.

Enhanced blood insulin overcomes pyruvate dehydrogenase derangements that reflect systemic insulin resistance in obese adolescents.

Pyruvate dehydrogenase (PDH) has low activity in the circulating lymphocytes (CL) of obese adolescents and adults. In vitro, it is unresponsive to insulin at 5 micro-units/ml and is activated at 50 micro-units/ml, in contrast with activation and inhibition respectively at these concentrations in CL from controls. These changes are seen as being indicative of a molecular disorder underlying insulin resistance. The aims of the present study were to determine whether a substantial enhancement of blood insulin levels restores the PDH activity in CL from obese adolescents and abolishes the in vitro alterations, and whether PDH activity and indices of insulin resistance are correlated. Six obese adolescents and six normal-weight controls underwent a 4 h frequently sampled intravenous glucose test with minimal model analysis, to bring about a sharp rise in blood insulin and provide a reliable index of insulin sensitivity (S(I)). PDH activity was evaluated in CL obtained from blood samples at set times before and after their exposure to insulin in vitro. Insulin levels rose in all subjects in the first 10 min, although to a much greater extent in the obese group, and then decreased until the end of the test (240 min; t(240)). PDH activity in CL paralleled the insulin pattern in the control subjects, whereas in the obese subjects it was below normal 3 min before the start of the test (t(-3)), but rose significantly throughout the test. PDH responses in vitro to insulin in CL taken from the control subjects at t(-3) and t(240) and in CL taken from the obese subjects at t(-3) were as reported above, but were normal (i.e. the same as in control CL) in CL taken from the obese subjects at t(240). Baseline PDH activity was inversely correlated with body mass index and with fasting insulin, and directly correlated with S(I). These results show that a brief and sharp enhancement of blood insulin overcomes derangements in PDH that reflect systemic insulin resistance in obese adolescents.