Insulin Metabolism and Assessment of Hepatic Insulin Extraction During Liver Regeneration. A Study in a Rat Model.

Background: Liver regeneration is a complex procedure in which insulin metabolism has been implicated. The aim of this experimental study was to evaluate the role of insulin in rat hepatic regeneration following major hepatectomy (70%), employing an isolated perfused rat liver (IPRL) model to assess the extraction of insulin from the regenerating liver. Methods: Eighty-six male rats were randomized in 9 groups. A group of rats was studied at postoperative day (POD) 1 having a sham operation while control rats had no operation. All other animals were subjected to 70% hepatectomy. In phase B, at POD 1, 2, 3, 5, 7, and 14, the IPRL was applied. The regenerating liver was perfused with insulin (450 mu/ml) at a flow of 1.4 ml/gr liver/min for 20 min. Animal weight, liver weight, glucose, lactate, aspartate transferase (AST), alanine transferase (ALT), total bilirubin, albumin, prothrombin time (PT), insulin clearance, and tissue proliferating cell nuclear antigen (PCNA) expression were recorded. Results: We observed reduction of the liver's biochemical activities resulting in increase of AST (684%), ALT (532%), PT (27.7%), international normalized ratio (72%), and total bilirubin (82.8%) at first POD, while a normalization of the essential liver's functions occurs at fifth POD. Endogenous insulin concentration increased, while insulin extraction by the liver was reduced at the first POD in animals who underwent hepatectomy (13.94 ± 0.8 vs 7.97 ± 1.80 u/ml, p = 0.0005 and 71 ± 9.9 vs 165.88 µU/gr liver/min, respectively, p = 0.0005). Conclusions: Insulin seems to take part in hepatic regeneration, as the pancreas increases insulin production and the liver absorbs less despite the reduced hepatic mass and function.

Saliva as a non-invasive tool for assessment of metabolic and inflammatory biomarkers in children.

BACKGROUND & AIMS: Epidemiological studies in school-age children are challenging, particularly those that aim to analyse metabolic markers on blood samples obtained via invasive and stressful procedures. The objective of this paper is to evaluate the use of saliva, as a non-invasive tool in epidemiological studies performed in school-age children, to capture metabolic changes associated with body mass index (BMI), dietary characteristics and physical activity in both boys and girls. METHODS: This is an observational study in which healthy children of ages between 8 and 12 years (n = 129, 60 girls and 69 boys) from three schools in a Mediterranean area of Spain were included. A panel of biomarkers was measured in serum and saliva and correlated with BMI, dietary characteristics and physical activity. RESULTS: Significant positive correlation between serum and salivary levels were detected for CRP (r = 0.770) in all included children, and boys (r = 0.805) and girls (r = 0.775) separately (P < 0.001, in all cases) and for insulin in girls (r = 0.442; P < 0.05). Among all studied salivary biomarkers, insulin was significantly correlated with the three factors studied: positively with BMI and negatively with dietary characteristics (intake and composition) and physical activity (P < 0.05). Obesity and diet composition were both positively associated to pro-inflammatory biomarkers, CRP and IL1b; while diet composition shared with physical activity levels the correlation with IL6 (positive with energy, fat, carbohydrate and saturated fatty acid intake, and negative with cholesterol intake and average physical activity in boys), NGF and glucose (in both cases correlations were negative with diet composition and physical activity variables) (P < 0.05, in all cases). Sex differences were detected in serum glucose and TNFα. CONCLUSIONS: Biomarkers in saliva are able to capture differences in BMI, dietary characteristics and physical activity levels in school-age children. Saliva may potentially constitute a useful non-invasive and stress-free tool to evaluate metabolic markers of inflammation and/or metabolism related to BMI and lifestyle in a sex-dependent manner.

Optimal Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) Cut-Offs: A Cross-Sectional Study in the Czech Population.

Background and Objectives: The key pathogenetic mechanism of glucose metabolism disorders, insulin resistance (IR), can be assessed using the Homeostasis Model Assessment of IR (HOMA-IR). However, its application in clinical practice is limited due to the absence of cut-offs. In this study, we aimed to define the cut-offs for the Czech population. Methods: After undergoing anthropometric and biochemical studies, the sample of 3539 individuals was divided into either nondiabetics, including both subjects with normal glucose tolerance (NGT, n = 1947) and prediabetics (n = 1459), or diabetics (n = 133). The optimal HOMA-IR cut-offs between subgroups were determined to maximize the sum of the sensitivity and specificity for diagnosing type 2 diabetes mellitus (T2DM) or prediabetes. The predictive accuracy was illustrated using receiver operating characteristic (ROC) curves. Logistic regression was performed to assess the association between a target variable (presence/absence of T2DM) depending on the HOMA-IR score as well as on the age and sex. Results: The HOMA-IR cut-off between nondiabetics and diabetics for both sexes together was 3.63, with a sensitivity of 0.56 and a specificity of 0.86. The area under the ROC curve was 0.73 for T2DM diagnosing in both sexes. The HOMA-IR cut-off between the NGT subjects and prediabetics was 1.82, with a sensitivity of 0.60 and a specificity of 0.66. Logistic regression showed that increased HOMA-IR is a risk factor for the presence of T2DM (odds ratio (OR) 1.2, 95% confidence interval (CI) 1.14-1.28, p < 0.0001). The predictive ability of HOMA-IR in diagnosing T2DM is statistically significantly lower in females (OR 0.66, 95% CI 0.44-0.98). The results are valid for middle-aged European adults. Conclusions: The results suggest the existence of HOMA-IR cut-offs signaling established IR. Introduction of the instrument into common clinical practice, together with the known cut-offs, may contribute to preventing T2DM.

Burnout Syndrome in Physicians-Psychological Assessment and Biomarker Research.

Background and objectives: Burnout is a syndrome typically occurring in work environments with continuous and chronic stress. Physicians are at increased risk for burnout, as a result of 24-hour work, delayed work-life balance gratification, and the challenges associated with patient care. The aim of the present study was to evaluate the psychological parameters of burnout symptoms in relation to biomarkers of stress among physicians with different medical specialties. Materials and methods: A total of 303 physicians were contacted as potential participants. A comparison group of 111 individuals working outside medicine was used as a control to verify the results. The physicians were specialists in internal medicine, general surgery, pathology, and primary care. Serum cortisol, salivary cortisol, adrenocorticotropic hormone (ACTH), insulin (IRI), and prolactin levels were analyzed by chemiluminescence enzyme immunoassay (Access 2, Beckman Coulter). Fasting glucose in serum and glycated hemoglobin (HbA1C) in whole blood were measured using the automatic analyzer AU 480 Beckman Coulter system. Symptoms of burnout were measured with the Maslach Burnout Inventory (MBI). Results: The group with burnout presented significantly higher levels of serum and saliva cortisol, ACTH, prolactin, fasting glucose, and HbA1C compared with the control group. The correlation analysis between biomarkers showed a positive correlation with moderate strength between serum and saliva cortisol (r = 0.516, p = 0.01),as well as serum and saliva cortisol with ACTH (r = 0.418; r = 0.412, p = 0.01) and HbA1C (r = 0.382; r = 0.395, p = 0.01). A weak positive correlation was found between serum and saliva cortisol with prolactin (r = 0.236; r = 0.267, p < 0.01) and glucose (r = 0.271; r = 0.297, p < 0.01). In the multiple logistic regression model, saliva cortisol, HbA1C, and age were significantly associated with burnout (chi-square = 16.848, p < 0.032). Conclusion: Our findings demonstrated the interest of exploring biomarkers of stress related to burnout in health professionals.

Videogames That Encourage Healthy Behavior Did Not Alter Fasting Insulin or Other Diabetes Risks in Children: Randomized Clinical Trial.

Background: Previous research indicates games for health have substantial promise in promoting change in children's diet and physical activity (PA) behavior for obesity and diabetes prevention, but the research has generally not been rigorous. The study reported here was an efficacy trial of two role-playing videogames played in sequence, "Escape from Diab" (hereinafter called Diab) and "Nanoswarm: Invasion from Inner Space" (hereinafter called Nano), on diabetes and obesity risk factors: fasting insulin and body mass index (BMI), and risk-related behaviors: diet, PA, and sedentary behavior (SB). Design: A two-group (treatment vs. wait list control) randomized clinical trial was used with baseline, immediate postintervention (∼3 months postbaseline), and 2 months postassessments. Intervention: Diab and Nano were desktop or laptop role-playing videogames with nine sessions (each episode/session lasting ∼60 minutes). Two storylines attempted to immerse players and used ethnically diverse characters to model desired behaviors. Tailored goal setting, problem solving, and motivational statements were used. Methods: A sample of 200 overweight or obese children (ages 10-12 years from 85th to 99th BMI percentile [%ile]) was recruited, primarily using a volunteer list. Fasting insulin was the primary dependent variable. BMI, fruit, vegetable and sweetened beverage intakes, PA, and SBs were secondary outcomes. Generalized linear mixed models were used to test for the treatment effects. Results: No significant differences were detected in any of the tested outcome variables. Conclusions: The lack of differences may indicate that games cannot change dietary behaviors and thereby not change-related clinical outcomes. Alternatively, there seem to have been changes in (1) the types of videogames children expect and like to play since a pilot study was conducted, (2) productization challenges, and/or (3) problems in staff management of the trial. All may have contributed to the lack of effect.

Encompassing ATP, DNA, insulin, and protein content for quantification and assessment of human pancreatic islets.

Islet transplantation has made major progress to treat patients with type 1 diabetes. Islet mass and quality are critically important to ensure successful transplantation. Currently, islet status is evaluated using insulin secretion, oxygen consumption rate, or adenosine triphosphate (ATP) measurement. These parameters are evaluated independently and do not effectively predict islet status post-transplant. Therefore, assessing human pancreatic islets by encompassing ATP, DNA, insulin, and protein content from a single tissue sample would serve as a better predictor for islet status. In this study, a single step procedure for extracting ATP, DNA, insulin, and protein content from human pancreatic islets was described and the biomolecule contents were quantified. Additionally, different mathematical calculations integrating total ATP, DNA, insulin, and protein content were randomly tested under various conditions to predict islet status. The results demonstrated that the ATP assay was efficient and the biomolecules were effectively quantified. Furthermore, the mathematical formula we developed could be optimized to predict islet status. In conclusion, our results indicate a proof-of-concept that a simple logarithmic formula can predict overall islet status for various conditions when total islet ATP, DNA, insulin, and protein content are simultaneously assessed from a single tissue sample.

Correlation of the Homeostasis Model Assessment Index and Adiponectin, Leptin and Insulin Levels to Body Mass Index-Associated Gene Polymorphisms in Adolescents.

OBJECTIVES: This study aimed to describe correlations between glucose, insulin and adipokine levels and the homeostasis model assessment (HOMA) index with regards to the presence/absence of fat mass and obesity-associated (FTO) rs9939609 and peroxisome proliferator-activated receptor (PPAR)-y rs1801282 single nucleotide polymorphisms (SNPs) as indicators of body mass index in adolescents. METHODS: This cross-sectional study was conducted between September and December 2016 in Toluca, Mexico. A total of 71 students between 14-18 years old were included. Various anthropometric and laboratory measurements were collected, including lipid profile, glucose, insulin and adipokine levels and HOMA index. The degree of association between variables was evaluated with regards to the presence/absence of the SNPs. RESULTS: Leptin levels were significantly higher among female students (P = 0.001), although adiponectin levels did not differ significantly (P = 0.060). There were significant positive correlations between insulin levels and HOMA index with FTO (r = 0.391; P = 0.007 and r = 0.413; P = 0.005, respectively) and PPARγ (r = 0.529; P = 0.007 and r = 0.537; P = 0.007, respectively) SNPs. Leptin showed a significant positive correlation in the presence of PPARγ (r = 0.483; P = 0.007) or in the absence of both SNPs (r = 0.627; P = 0.039). However, adiponectin was significantly negatively correlated in the presence of FTO, either alone (r = -0.333; P = 0.024) or in combination with PPARγ (r = -0.616; P = 0.043). CONCLUSION: The presence of FTO and/or PPARγ SNPs might be related to a genetic predisposition to metabolic syndrome.

Is insulin diluted when stored in water?

BACKGROUND: Insulin storage is a challenge in resource-poor countries. In Uganda, patients were noted to store insulin vials by submerging them in water. OBJECTIVE: To examine whether withdrawing insulin from a vial without adding air back causes a vacuum which allows water to enter the vial, resulting in insulin dilution. METHODS: Seven hundred units of insulin were withdrawn from forty 10 mL vials of 100 units/mL insulin [20 neutral protamine hagedorn (NPH), 20 regular]. In half, air was added back. The vials were weighed (baseline). Half of the vials (10 with added air, 10 without) were submerged in water for 24 h and then air-dried for 24 h. Vials that were not submerged sat at room temperature for 48 h. All vials were weighed 48 h from baseline. RESULTS: Addition of air did not impact the change in weight after submersion (air added: -0.002 ± 0.001 g or -0.2 ± 0.1 unit; no air added: -0.003 ± 0.000 g or -0.3 ± 0 unit, p = 0.57). In a subset of vials in which an additional 240 units were withdrawn before submersion for another 24 h, there was still no difference in weight change in those vials with air added (p = 0.2). CONCLUSION: Withdrawing insulin from a vial without adding air did not result in uptake of water or dilution of insulin in the submerged vial, although it made drawing up the insulin easier. This study did not address the larger concern of bacterial contamination of the rubber stopper during water storage.

A stable isotope method for in vivo assessment of human insulin synthesis and secretion.

AIMS: In vitro, beta cells immediately secrete stored but readily releasable insulin in response to a rise of glucose. During a prolonged insulin response, this is followed by newly synthesized insulin. Our aim was to develop an in vivo test to determine the ratio between readily available and newly synthesized insulin after a stimulus in humans by labelling newly synthesized insulin. METHODS: A stable isotope tracer of 1.0 g 13C leucine with C-peptide as target peptide was administered 45 min prior to 75 g glucose load of a frequently blood sampled 210-min oral glucose tolerance test (OGTT). Our OGTT also encompassed collection of urine, which has a high content of C-peptide. Prior, the optimal conditions under which the tracer 13C leucine was administered for enrichment of (pre) proinsulin were established. Also, techniques to obtain urinary C-peptide under highly purified circumstances were set up. Our main outcome measure was the stable isotope enrichment of de novo C-peptide, which we related to early plasma insulin and glucose AUC. Twelve healthy Caucasian individuals (M4F8, age 41.8 ± 2.3, BMI 28.3 ± 1.7) with normal glucose tolerance underwent our OGTT. RESULTS: We found that during a 75-g OGTT, newly synthesized insulin contributed approximately 20 % of total insulin secretion. The pattern of isotope enrichment obtained by collecting multiple urine voids was suggestive that the newly synthesized insulin contributes to the late phase of insulin secretion. De novo C-peptide correlated negatively with both early plasma insulin AUC (r = -0.629, P = 0.028) and early plasma glucose AUC (r = -0.605, P = 0.037). CONCLUSIONS: With stable isotope technique added to OGTT, we were able to measure newly synthesized insulin in healthy individuals. This new technique holds the promise that it is feasible to develop a direct in vivo beta cell function test.

Investigation of asparagine deamidation in a SOD1-based biosynthetic human insulin precursor by MALDI-TOF mass spectrometry.

A biosynthetic human insulin precursor displayed enhanced susceptibility to deamidation at one particular site. The present study was undertaken to monitor progress of precursor deamidation at successive manufacturing stages. MALDI-TOF/TOF MS in combination with controlled endoproteinase Glu-C and endoproteinase Asp-N proteolysis was used for rapid and unambiguous determination of deamidated residue within the investigated structure. Close inspection of isotopic distribution patterns of peptides resulting from enzymatic digestion enabled determination of distinct precursor forms occurring during the production process. Asn, Asp, isoAsp and succinimide derivatives of the amino acid at position 26 were unambiguously identified. These modifications are related to the leader peptide of a precursor encompassing amino acid sequence corresponding to that of superoxide dismutase [Cu-Zn] (SOD1 1, EC=1.15.1.1). Monitoring of precursor deamidation process at successive manufacturing stages revealed that the protein folding stage was sufficient for a prominent replacement of asparagine by aspartic and isoaspartic acid and the deamidated human insulin precursor constituted the main manufactured product. Conversion proceeded through a succinimide intermediate. Significant deamidation is associated with the presence of SNG motif and confirms results achieved previously on model peptides. Our findings highlight an essential role of the specific amino acid sequence on accelerated rate of protein deamidation. To our knowledge, this is the first time that such a dramatic change in the relative abundance of Asp and isoAsp resulting from protein deamidation process is reported.

Sensitive detection of human insulin using a designed combined pore approach.

A unique combined pore approach to the sensitive detection of human insulin is developed. Through a systematic study to understand the impact of pore size and surface chemistry of nanoporous materials on their enrichment and purification performance, the advantages of selected porous materials are integrated to enhance detection sensitivity in a unified two-step process. In the first purification step, a rationally designed large pore material (ca. 100 nm in diameter) is chosen to repel the interferences from nontarget molecules. In the second enrichment step, a hydrophobically modified mesoporous material with a pore size of 5 nm is selected to enrich insulin molecules. A low detection limit of 0.05 ng mL(-1) in artificial urine is achieved by this advanced approach, similar to most antibody-based analysis protocols. This designer approach is efficient and low cost, and thus has great potential in the sensitive detection of biomolecules in complex biological systems.

Comparison of bioanalytical methods for the quantitation of PEGylated human insulin.

PURPOSE: The quality of bioanalytical data is dependent upon selective, sensitive, and reproducible analytical methods. With evolving technologies available, bioanalytical scientists must assess which is most appropriate for their molecule through proper method validation. For an early stage PEGylated insulin program, the characteristics of four platforms, ELISA, ECL, Gyrolab, and LC-MS/MS, were evaluated using fit-for-purpose method development and validation, while also evaluating costs. METHOD: Methods selected for validation required acceptable performance based on satisfaction of a priori criteria prior to proceeding to subsequent stages of validation. LBA pre-validation included reagent selection, evaluation of matrix interference, and range determination. LC-MS/MS pre-validation included selection of a signature peptide; optimization of sample preparation, HPLC, and LC-MS/MS conditions; and calibration range determination. Pre-study validation tested accuracy and precision (mean bias criteria±30%; precision≤30%). Pharmacokinetic (PK) parameters were estimated for an in vivo study with WinNonlin noncompartmental analysis. Statistics were performed with JMP using ANOVA and Tukey-Kramer post hoc analysis. A cost analysis was performed for a 200-sample PK study using the methods from this study. RESULTS: All platforms, except Gyrolab, were taken through validation. However, a typical Gyrolab method was included for the cost analysis. Ranges for the ELISA, ECLA, and LC-MS/MS were 8.52-75, 2.09-125, and 100-1000 ng/mL, respectively, and accuracy and precision fell within a priori criteria. PK samples were analyzed in the 3 validated methods. PK profiles and parameters are similar for all methods, except LC-MS/MS, which differed at t=24h and with AUC0-24. Further investigation into this difference is warranted. The cost analysis identified the Gyrolab platform as the most expensive and ELISA as the least expensive, with method specific consumables attributing significantly to costs. CONCLUSIONS: ECLA had a larger dynamic range and sensitivity, allowing accurate assessment of PK parameters. Although this method was more expensive than the ELISA, it was the most appropriate for the early stage PEGylated insulin program. While this case study is specific to PEGylated human insulin, it highlights the importance of evaluating and selecting the most appropriate platform for bioanalysis during drug development.

Quantitative insulin analysis using liquid chromatography-tandem mass spectrometry in a high-throughput clinical laboratory.

BACKGROUND: Circulating insulin concentrations reflect the amount of endogenous insulin produced by the pancreas and can be monitored to check for insulin resistance. Insulin is commonly measured using immunochemiluminometric assays (ICMA). Unfortunately, differing crossreactivities of the various ICMA antibodies have led to variability in assay results. In contrast, liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based approaches can provide a highly specific alternative to immunoassays. METHODS: Insulin was extracted from patient serum and reduced to liberate the insulin B chain. Subsequent resolution of the peptide was achieved by LC coupled to triple-quadrupole MS. Selected-reaction monitoring of B-chain transitions was used for quantification. Recombinant human insulin was used as a calibrator and was compared against the National Institute for Biological Standards and Control (NIBSC) reference standard. Bovine insulin and a stable isotopic-labeled ((13)C/(15)N) human insulin B chain were used and compared as internal standards. RESULTS: The LC-MS/MS assay described herein has been validated according to CLIA guidelines with a limit of detection of 1.8 µIU/mL (10.8 pmol/L) and a limit of quantitation of 3 µIU/mL (18.0 pmol/L). A correlation between the LC-MS/MS assay and a US Food and Drug Administration-approved ICMA was completed for patient samples and the resulting Deming regression revealed good agreement. A reference interval for the assay was established. CONCLUSIONS: A simple, high-throughput, quantitative LC-MS/MS insulin assay traceable to the NIBSC standard has been successfully developed and validated.

Quantitative histopathological assessment of retardation of islets of langerhans degeneration in rosiglitazone-dosed obese ZDF rats using combined insulin and collagens (I and III) immunohistochemistry with automated image analysis and statistical modeling.

Islets of Langerhans represent a heterogeneous population in insulin resistant and diabetic animals and humans as histological appearances and function vary substantially. Mathematical representation that reflects this morphological diversity will assist in assessment of degeneration and regeneration, enabling comparisons between species, strains, and experimental investigations. Our investigative approach used a model of islet degeneration in diabetic male obese Zucker Diabetic Fatty (ZDF) rats and evaluated its prevention using rosiglitazone treatment. Immunohistochemical staining (insulin and collagens I/III) with automated image analysis reliably measured numbers, area, clustering, and staining intensity of ß-cells and degree of islet fibrosis. Finite mixture mathematical modeling for the joint probability distribution of seven islet parameters to represent islet numerical data variation provided an automatic procedure for islet category allocations as normal or abnormal. Allocations for obese ZDF controls and rosiglitazone-treated animals were significantly different, with no significant difference between the latter and lean ZDF controls, indicative of differences within islet populations of individual animals, between lean and obese rat strains and following drug treatment. Islet morphology showed clear association with mathematical characterization. Information on islet morphology obtained by histopathological assessment of single pancreatic tissue sections was confirmed by this method showing drug-induced retardation of islet of Langerhans degeneration.

Assessment of the mechanisms exerting glucose-lowering effects of dried peas in glucose-intolerant rats.

The present study compared the effects of feeding uncooked pea fractions (embryo v. seed coat) on glucose homeostasis in glucose-intolerant rats and examined potential mechanisms influencing glucose homeostasis. Rats were made glucose intolerant by high-fat feeding, after which diets containing both high-fat and pea fractions were fed for 4 weeks. Rats fed diets containing uncooked pea seed coats low (non-coloured seed coat; NSC) or high (coloured seed coat; CSC) in proanthocyanidins but not embryos had improved oral glucose tolerance (P < 0·05). NSC also lowered fasting and glucose-stimulated insulin secretion (P < 0·05), decreased ß-cell mass by 50 % (P < 0·05) and lowered levels of malondialdehyde, a marker of oxidative stress. Furthermore, NSC decreased the mucosal thickness of the colon by 25 % (P < 0·05), which might affect fibre fermentation and other gut functions. Small but statistically significant (P < 0·05) effects consistent with enhanced glucose transport or metabolism were observed in the skeletal muscle of rats fed NSC or CSC, for example, increased levels of AMP-dependent kinase or akt. We conclude that pea seed coats are the fraction exerting beneficial effects on glucose tolerance. Most of the changes were small in amplitude, suggesting that additive effects on multiple tissues may be important. NSC content appeared to have the most beneficial effects in improving glucose homeostasis but our ability to detect the effect of flavonoids may have been limited by their low concentration in the diet.

Assessment of childhood obesity in secondary care: OSCA consensus statement.

This expert opinion provides detailed guidance on assessing obesity in secondary paediatric practice. This guidance builds on existing recommendations from National Institute of Health and Clinical Excellence in the UK, and is evidence based where possible. Guidance is provided on which obese children and young people are appropriate to be seen in secondary care and relevant history and investigations, and guidance on when further investigation of causes and obesity-related comorbidity is appropriate.

An evaluation of diabetes self-management applications for Android smartphones.

We reviewed diabetes apps for Android smartphones. We compiled a list of free and paid apps in April 2011 by searching the Android Market for apps which could track self-monitoring of blood glucose (SMBG), diabetes medications or calculate prandial insulin dosages. Two reviewers independently evaluated six features per app, using a five-point Likert scale. The sum of the six ratings was the composite usability score, and the mean score of an app's features was the average usability score. Of the 80 Android diabetes apps identified, 42 unique apps were eligible for the study. SMBG recording was present in 36 (86%) of the apps, a tool to track insulin or oral diabetic medications was found in 19 (45%) apps, and a prandial insulin dose calculator existed for 11 (26%) apps. Eighteen apps were free of charge and the other 24 apps had a mean purchase price of $2.86 (range 0.99-6.99). The mean composite usability score was 11.3 out of a possible 30. The mean average usability score was 3.0 out of a possible 5.0. Only four of the 42 apps had a composite usability score above 20 and none offered direct data input from glucometers, suggesting that few provided a comprehensive method of diabetes management. The apps Glucool Diabetes, OnTrack Diabetes, Dbees and Track3 Diabetes Planner were the highest rated. Clinicians may find it useful to recommend these apps.

Assessment of Leydig and Sertoli cell functions in infants with nonmosaic Klinefelter syndrome: insulin-like peptide 3 levels are normal and positively correlated with LH levels.

CONTEXT: Klinefelter syndrome (KS) is the most common sex chromosome disorder and a major cause of male infertility. In adult patients, serum inhibin B and anti-Mullerian-hormone (AMH) are undetectable, testosterone secretion is often impaired, and the tubules are depleted of germ cells. Before puberty, inhibin B, AMH, and testosterone levels are within the normal range. OBJECTIVE: Sertoli and Leydig cell secretions, including insulin-like peptide-3 (INSL3), were evaluated in infants with nonmosaic XXY karyotype to assess testicular function soon after birth. DESIGN: The study was conducted in four University Pediatric Departments from the United States and France. SUBJECTS: Sixty-eight prenatally diagnosed infants aged 2-750 d were enrolled. MAIN OUTCOME MEASURES: Serum FSH, LH, inhibin B, AMH, and INSL3 were measured by immunoassay, and testosterone was measured by tandem mass-spectrometry. RESULTS: In infants with KS, INSL3 levels transiently increased at 2-3 months of age and were significantly correlated with testosterone (Spearman r = 0.57) and LH (Spearman r = 0.73) levels. They did not differ from controls. Testosterone levels were within the normal range, but most of them were below the median of controls. Inhibin B and AMH levels were also within normal range. Inhibin B was correlated with FSH (Spearman r = 0.49). AMH was not correlated with FSH or testosterone. FSH levels were above normal in 25% of patients, despite normal inhibin B levels. CONCLUSIONS: In infants with KS, Leydig cells are normally sensitive to the LH proliferative effect. In contrast, the Sertoli cell sensitivity to FSH is questionable, which may be prophetic of the postpubertal Sertoli cell resistance to FSH.

Homogeneous insulin and C-Peptide sensors for rapid assessment of insulin and C-peptide secretion by the islets.

OBJECTIVE: Glucose-stimulated islet insulin or C-peptide secretion experiments are a fundamental tool for studying and assessing islet function. The goal of this work was to develop Ab-based fluorescent homogenous sensors that would allow rapid, inexpensive, near-instantaneous determinations of insulin and C-peptide levels in biological samples. RESEARCH DESIGN AND METHODS: Our approach was to use molecular pincer design (Heyduk et al., Anal Chem 2008;80:5152-5159) in which a pair of antibodies recognizing nonoverlapping epitopes of the target are modified with short fluorochrome-labeled complementary oligonucleotides and are used to generate a fluorescence energy transfer (FRET) signal in the presence of insulin or C-peptide. RESULTS: The sensors were capable of detecting insulin and C-peptide with high specificity and with picomolar concentration detection limits in times as short as 20 min. Insulin and C-peptide levels determined with the FRET sensors showed outstanding correlation with determinations performed under the same conditions with enzyme-linked immunosorbent assay. Most importantly, the sensors were capable of rapid and accurate determinations of insulin and C-peptide secreted from human or rodent islets, verifying their applicability for rapid assessment of islet function. CONCLUSIONS: The homogeneous, rapid, and uncomplicated nature of insulin and C-peptide FRET sensors allows rapid assessment of ß-cell function and could enable point-of-care determinations of insulin and C-peptide.

Assessment of the predictive value of follicular fluid insulin, leptin and adiponectin in assisted reproductive cycles.

PURPOSE: To assess the correlation of intrafollicular insulin, leptin and adiponectin levels with assisted reproductive technologies (ART) outcome. METHODS: This was a retrospective study of 46 patients undergoing in vitro fertilisation/intracytoplasmic sperm injection. Follicular fluid (FF) samples collected at oocyte retrieval were assayed for insulin, leptin and adiponectin levels using enzyme-linked immunosorbent assay, and correlations with ART outcome were analysed. RESULTS: There was no significant correlation between intrafollicular insulin, leptin and adiponectin levels. There was a significant difference in the concentration of insulin (P = 0.007), but not leptin or adiponectin, between pregnant (n = 20) and non-pregnant (n = 26) cycles. Only two pregnancies was observed in the 12 cycles in which the concentration of insulin was greater than 7 mU/l in FF, while 18 pregnancies was observed in the 34 cycles in which the concentration of insulin was less than 7 mU/l (P = 0.043). The significantly high concentration of insulin in FF was observed in non-pregnant cycles of patients with polycystic ovary syndrome (PCOS). CONCLUSIONS: Our results suggest the possible involvement of intrafollicular insulin in folliculogenesis. Insulin resistance-related substances may affect the reproductive process in patients with PCOS.