Classification of Hypoglycemic Events in Type 1 Diabetes Using Machine Learning Algorithms.

INTRODUCTION: To improve the utilization of continuous- and flash glucose monitoring (CGM/FGM) data we have tested the hypothesis that a machine learning (ML) model can be trained to identify the most likely root causes for hypoglycemic events. METHODS: CGM/FGM data were collected from 449 patients with type 1 diabetes. Of the 42,120 identified hypoglycemic events, 5041 were randomly selected for classification by two clinicians. Three causes of hypoglycemia were deemed possible to interpret and later validate by insulin and carbohydrate recordings: (1) overestimated bolus (27%), (2) overcorrection of hyperglycemia (29%) and (3) excessive basal insulin presure (44%). The dataset was split into a training (n = 4026 events, 304 patients) and an internal validation dataset (n = 1015 events, 145 patients). A number of ML model architectures were applied and evaluated. A separate dataset was generated from 22 patients (13 'known' and 9 'unknown') with insulin and carbohydrate recordings. Hypoglycemic events from this dataset were also interpreted by five clinicians independently. RESULTS: Of the evaluated ML models, a purpose-built convolutional neural network (HypoCNN) performed best. Masking the time series, adding time features and using class weights improved the performance of this model, resulting in an average area under the curve (AUC) of 0.921 in the original train/test split. In the dataset validated by insulin and carbohydrate recordings (n = 435 events), i.e. 'ground truth,' our HypoCNN model achieved an AUC of 0.917. CONCLUSIONS: The findings support the notion that ML models can be trained to interpret CGM/FGM data. Our HypoCNN model provides a robust and accurate method to identify root causes of hypoglycemic events.

Altered glucose-dependent secretion of glucagon and ACTH is associated with insulin resistance, assessed by population analysis.

This study aimed to characterize how the dysregulation of counter-regulatory hormones can contribute to insulin resistance and potentially to diabetes. Therefore, we investigated the association between insulin sensitivity and the glucose- and insulin-dependent secretion of glucagon, adrenocorticotropic hormone (ACTH), and cortisol in non-diabetic individuals using a population model analysis. Data, from hyperinsulinemic-hypoglycemic clamps, were pooled for analysis, including 52 individuals with a wide range of insulin resistance (reflected by glucose infusion rate 20-60 min; GIR20-60min). Glucagon secretion was suppressed by glucose and, to a lesser extent, insulin. The GIR20-60min and BMI were identified as predictors of the insulin effect on glucagon. At normoglycemia (5 mmol/L), a 90% suppression of glucagon was achieved at insulin concentrations of 16.3 and 43.4 µU/mL in individuals belonging to the highest and lowest quantiles of insulin sensitivity, respectively. Insulin resistance of glucagon secretion explained the elevated fasting glucagon for individuals with a low GIR20-60min. ACTH secretion was suppressed by glucose and not affected by insulin. The GIR20-60min was superior to other measures as a predictor of glucose-dependent ACTH secretion, with 90% suppression of ACTH secretion by glucose at 3.1 and 3.5 mmol/L for insulin-sensitive and insulin-resistant individuals, respectively. This difference may appear small but shifts the suppression range into normoglycemia for individuals with insulin resistance, thus, leading to earlier and greater ACTH/cortisol response when the glucose falls. Based on modeling of pooled glucose-clamp data, insulin resistance was associated with generally elevated glucagon and a potentiated cortisol-axis response to hypoglycemia, and over time both hormonal pathways may therefore contribute to dysglycemia and possibly type 2 diabetes.

Does bilingualism come with linguistic costs? A meta-analytic review of the bilingual lexical deficit.

A series of recent studies have shown that the once-assumed cognitive advantage of bilingualism finds little support in the evidence available to date. Surprisingly, however, the view that bilingualism incurs linguistic costs (the so-called lexical deficit) has not yet been subjected to the same degree of scrutiny, despite its centrality for our understanding of the human capacity for language. The current study implemented a comprehensive meta-analysis to address this gap. By analyzing 478 effect sizes from 130 studies on expressive vocabulary, we found that observed lexical deficits could not be attributed to bilingualism: Simultaneous bilinguals (who acquired both languages from birth) did not exhibit any lexical deficit, nor did sequential bilinguals (who acquired one language from birth and a second language after that) when tested in their mother tongue. Instead, systematic evidence for a lexical deficit was found among sequential bilinguals when tested in their second language, and more so for late than for early second language learners. This result suggests that a lexical deficit may be a phenomenon of second language acquisition rather than bilingualism per se.

Postprandial Normoglycemic Hypokalemia-an Overlooked Complication to Gastric Bypass Surgery?

Obesity is one of the major health problems of the world, and one of the most common surgical treatments is the Roux-en-Y gastric bypass surgery. This can however lead to problems with postprandial hypoglycemia, but sometimes, the meal test does not render any signs of hypoglycemia. Here, 3 cases are presented with postprandial normoglycemic hypokalemia.

Effect of Continued Weekly Subcutaneous Semaglutide vs Placebo on Weight Loss Maintenance in Adults With Overweight or Obesity: The STEP 4 Randomized Clinical Trial.

Importance: The effect of continuing vs withdrawing treatment with semaglutide, a glucagon-like peptide 1 receptor agonist, on weight loss maintenance in people with overweight or obesity is unknown. Objective: To compare continued once-weekly treatment with subcutaneous semaglutide, 2.4 mg, with switch to placebo for weight maintenance (both with lifestyle intervention) in adults with overweight or obesity after a 20-week run-in with subcutaneous semaglutide titrated to 2.4 mg weekly. Design, Setting, and Participants: Randomized, double-blind, 68-week phase 3a withdrawal study conducted at 73 sites in 10 countries from June 2018 to March 2020 in adults with body mass index of at least 30 (or ≥27 with ≥1 weight-related comorbidity) and without diabetes. Interventions: A total of 902 participants received once-weekly subcutaneous semaglutide during run-in. After 20 weeks (16 weeks of dose escalation; 4 weeks of maintenance dose), 803 participants (89.0%) who reached the 2.4-mg/wk semaglutide maintenance dose were randomized (2:1) to 48 weeks of continued subcutaneous semaglutide (n = 535) or switched to placebo (n = 268), plus lifestyle intervention in both groups. Main Outcomes and Measures: The primary end point was percent change in body weight from week 20 to week 68; confirmatory secondary end points were changes in waist circumference, systolic blood pressure, and physical functioning (assessed using the Short Form 36 Version 2 Health Survey, Acute Version [SF-36]). Results: Among 803 study participants who completed the 20-week run-in period (with a mean weight loss of 10.6%) and were randomized (mean age, 46 [SD, 12] years; 634 [79%] women; mean body weight, 107.2 kg [SD, 22.7 kg]), 787 participants (98.0%) completed the trial and 741 (92.3%) completed treatment. With continued semaglutide, mean body weight change from week 20 to week 68 was -7.9% vs +6.9% with the switch to placebo (difference, -14.8 [95% CI, -16.0 to -13.5] percentage points; P < .001). Waist circumference (-9.7 cm [95% CI, -10.9 to -8.5 cm]), systolic blood pressure (-3.9 mm Hg [95% CI, -5.8 to -2.0 mm Hg]), and SF-36 physical functioning score (2.5 [95% CI, 1.6-3.3]) also improved with continued subcutaneous semaglutide vs placebo (all P < .001). Gastrointestinal events were reported in 49.1% of participants who continued subcutaneous semaglutide vs 26.1% with placebo; similar proportions discontinued treatment because of adverse events with continued semaglutide (2.4%) and placebo (2.2%). Conclusions and Relevance: Among adults with overweight or obesity who completed a 20-week run-in period with subcutaneous semaglutide, 2.4 mg once weekly, maintaining treatment with semaglutide compared with switching to placebo resulted in continued weight loss over the following 48 weeks. Trial Registration: ClinicalTrials.gov Identifier: NCT03548987.

Effects of Gastric Bypass Surgery on the Brain: Simultaneous Assessment of Glucose Uptake, Blood Flow, Neural Activity, and Cognitive Function During Normo- and Hypoglycemia.

While Roux-en-Y gastric bypass (RYGB) surgery in obese individuals typically improves glycemic control and prevents diabetes, it also frequently causes asymptomatic hypoglycemia. Previous work showed attenuated counterregulatory responses following RYGB. The underlying mechanisms as well as the clinical consequences are unclear. In this study, 11 subjects without diabetes with severe obesity were investigated pre- and post-RYGB during hyperinsulinemic normo-hypoglycemic clamps. Assessments were made of hormones, cognitive function, cerebral blood flow by arterial spin labeling, brain glucose metabolism by 18F-fluorodeoxyglucose (FDG) positron emission tomography, and activation of brain networks by functional MRI. Post- versus presurgery, we found a general increase of cerebral blood flow but a decrease of total brain FDG uptake during normoglycemia. During hypoglycemia, there was a marked increase in total brain FDG uptake, and this was similar for post- and presurgery, whereas hypothalamic FDG uptake was reduced during hypoglycemia. During hypoglycemia, attenuated responses of counterregulatory hormones and improvements in cognitive function were seen postsurgery. In early hypoglycemia, there was increased activation post- versus presurgery of neural networks in brain regions implicated in glucose regulation, such as the thalamus and hypothalamus. The results suggest adaptive responses of the brain that contribute to lowering of glycemia following RYGB, and the underlying mechanisms should be further elucidated.

Altered hormonal and autonomic nerve responses to hypo- and hyperglycaemia are found in overweight and insulin-resistant individuals and may contribute to the development of type 2 diabetes.

AIMS/HYPOTHESIS: Results from animal models and some clinical work suggest a role for the central nervous system (CNS) in glucose regulation and type 2 diabetes pathogenesis by modulation of glucoregulatory hormones and the autonomic nervous system (ANS). The aim of this study was to characterise the neuroendocrine response to various glucose concentrations in overweight and insulin-resistant individuals compared with lean individuals. METHODS: Overweight/obese (HI, n = 15, BMI ≥27.0 kg/m2) and lean (LO, n = 15, BMI <27.0 kg/m2) individuals without diabetes underwent hyperinsulinaemic euglycaemic-hypoglycaemic clamps and hyperglycaemic clamps on two separate occasions with measurements of hormones, Edinburgh Hypoglycaemic Symptom Scale (ESS) score and heart rate variability (HRV). Statistical methods included groupwise comparisons with Mann-Whitney U tests, multilinear regressions and linear mixed models between neuroendocrine responses and continuous metabolic variables. RESULTS: During hypoglycaemic clamps, there was an elevated cortisol response in HI vs LO (median ΔAUC 12,383 vs 4793 nmol/l × min; p = 0.050) and a significantly elevated adrenocorticotropic hormone (ACTH) response in HI vs LO (median ΔAUC 437.3 vs 162.0 nmol/l × min; p = 0.021). When adjusting for clamp glucose levels, obesity (p = 0.033) and insulin resistance (p = 0.009) were associated with elevated glucagon levels. By contrast, parasympathetic activity was less suppressed in overweight individuals at the last stage of hypoglycaemia compared with euglycaemia (high-frequency power of HRV, p = 0.024). M value was the strongest predictor for the ACTH and PHF responses, independent of BMI and other variables. There was a BMI-independent association between the cortisol response and ESS score response (p = 0.024). During hyperglycaemic clamps, overweight individuals displayed less suppression of glucagon levels (median ΔAUC -63.4% vs -73.0%; p = 0.010) and more suppression of sympathetic relative to parasympathetic activity (low-frequency/high-frequency power, p = 0.011). CONCLUSIONS/INTERPRETATION: This study supports the hypothesis that altered responses of insulin-antagonistic hormones and the ANS to glucose fluctuations occur in overweight and insulin-resistant individuals, and that these responses are probably partly mediated by the CNS. Their potential role in development of type 2 diabetes needs to be addressed in future research. Graphical abstract.

Effects of GLP-1 on counter-regulatory responses during hypoglycemia after GBP surgery.

OBJECTIVES: The aim of the study was to explore the role of GLP-1 receptor activation on the counter-regulation and symptoms of hypoglycemia in subjects who have undergone gastric bypass surgery (GBP). DESIGN: Experimental hyperinsulinemic-hypoglycemic clamp study. METHODS: Twelve post-GBP subjects participated in a randomized cross-over study with two hyperinsulinemic, hypoglycemic clamps (glucose nadir 2.7 mmol/L) performed on separate days with concomitant infusions of the GLP-1 analog exenatide or with saline, respectively. Continuous measurements of metabolites and counter-regulatory hormones as well as assessments of heart rate variability and symptoms of hypoglycemia were performed throughout the clamps. RESULTS: No effect of GLP-1 receptor activation on counter-regulatory hormones (glucagon, catecholamines, cortisol, GH) or glucose infusion rate was seen, but we found indications of a downregulation of the sympathetic relative to the parasympathetic nerve activity, as reflected in heart rate variability. No significant differences in symptom of hypoglycemia were observed. CONCLUSIONS/INTERPRETATION: Short-term exposure to a GLP-1 receptor agonist does not seem to impact the counter-regulatory hormonal and metabolic responses in post-GBP subjects during hypoglycemic conditions, suggesting that the improvement in symptomatic hypoglycemia post-GBP seen following treatment with GLP-1 receptor agonists may be mediated by mechanism not directly involved in counter-regulation.

Is the Brain a Key Player in Glucose Regulation and Development of Type 2 Diabetes?

Ever since Claude Bernards discovery in the mid 19th-century that a lesion in the floor of the third ventricle in dogs led to altered systemic glucose levels, a role of the CNS in whole-body glucose regulation has been acknowledged. However, this finding was later overshadowed by the isolation of pancreatic hormones in the 20th century. Since then, the understanding of glucose homeostasis and pathology has primarily evolved around peripheral mechanism. Due to scientific advances over these last few decades, however, increasing attention has been given to the possibility of the brain as a key player in glucose regulation and the pathogenesis of metabolic disorders such as type 2 diabetes. Studies of animals have enabled detailed neuroanatomical mapping of CNS structures involved in glucose regulation and key neuronal circuits and intracellular pathways have been identified. Furthermore, the development of neuroimaging techniques has provided methods to measure changes of activity in specific CNS regions upon diverse metabolic challenges in humans. In this narrative review, we discuss the available evidence on the topic. We conclude that there is much evidence in favor of active CNS involvement in glucose homeostasis but the relative importance of central vs. peripheral mechanisms remains to be elucidated. An increased understanding of this field may lead to new CNS-focusing pharmacologic strategies in the treatment of type 2 diabetes.

Comparison of Meal Pattern and Postprandial Glucose Response in Duodenal Switch and Gastric Bypass Patients.

BACKGROUND: Bariatric surgery improves glucose homeostasis; however, side effects such as hypoglycemia can occur. We investigated the effects of meals on interstitial glucose (IG) response in biliopancreatic diversion with duodenal switch (BPD-DS) and Roux-en-Y gastric bypass (RYGBP)-operated patients at least 1 year after surgery. METHODS: Thirty patients treated with BPD-DS or RYGBP were recruited at the outpatient Obesity Unit, Uppsala University Hospital. IG was measured by continuous glucose monitoring (CGM) for 3 consecutive days, and postprandial IG levels from 5 to 120 min were analyzed for 2 of these days. All intake of food and beverages was simultaneously registered in a food diary, which was processed using The Meal Pattern Questionnaire. RESULTS: Postprandial IG levels were significantly lower in BPD-DS (n = 14) compared to RYGBP (n = 15)-treated patients, with mean concentrations of 5.0 (± 1.0) and 6.3 (± 1.8) mmol/L respectively (p < 0.001). The mean postprandial IG increment was lower in BPD-DS than in RYGBP patients, 0.2 (± 0.6) vs. 0.4 (± 1.4) mmol/L (p < 0.001). Furthermore, the postprandial IG variability was less pronounced in BPD-DS than in RYGBP patients. The mean number of daily meals did not differ between the two groups, 7.8 (± 2.6) in BPD-DS and 7.2 (± 1.7) in the RYGBP (p = 0.56). CONCLUSION: BPD-DS patients demonstrated lower postprandial IG concentrations, with smaller postprandial IG increments and less pronounced postprandial IG variability compared to RYGBP patients. The two groups had similar meal pattern and the postprandial IG responses is probably associated with differences in postoperative physiology.

Revisiting the bilingual lexical deficit: The impact of age of acquisition.

Whereas the cognitive advantages brought about by bilingualism have recently been called into question, the so-called 'lexical deficit' in bilinguals is still largely taken for granted. Here, we argue that, in analogy with cognitive advantages, the lexical deficit does not apply across the board of bilinguals, but varies as a function of acquisition trajectory. To test this, we implement a novel methodological design, where the variables of bilingualism and first/second language status have been fully crossed in four different groups. While the results confirm effects of bilingualism on lexical proficiency and processing, they show more robust effects of age of acquisition. We conclude that the traditional view of the linguistic costs of bilingualism need to give way to a new understanding of lexical development in which age of acquisition is seen as a major determinant.

Bariatric surgery - time to replace with GLP-1?

Obesity with a body mass index (BMI) over 30 kg/m2 represents a significant risk for increased morbidity and mortality, with reduced life expectancy of about 10 years. Until now, surgical treatment has been the only effective longterm intervention. The currently standardized method of bariatric surgery, gastric bypass, means that many gastrointestinal peptide hormones are activated, yielding net reductions in appetite and food intake. Among the most important gut peptide hormones in this perspective is glucagon-like peptide-1 (GLP-1), which rises sharply after gastric bypass. Consistent with outcomes of this surgery, GLP-1 suppresses appetite and reduces food intake. This implies that GLP-1 has the potential to achieve a similar therapeutic outcome as gastric bypass. GLP-1 analogs, which are used for the treatment of type 2 diabetes mellitus, also lead to significant weight loss. Altered hormonal profiles after gastric bypass therefore indicate a logical connection between gut peptide hormone levels, weight loss and glucose homeostasis. Furthermore, combinations of GLP-1 with other gut hormones such as peptide YY (PYY) and cholecystokinin (CCK) may be able to reinforce GLP-1 driven reduction in appetite and food intake. Pharmacological intenvention in obesity by use of GLP-1 analogs (exenatide, liraglutide, albiglutide, dulaglutide, lixisenatide, taspoglutide) and inhibitors of dipeptidyl peptidase-IV (DPP-IV) degradation that inactivate GLP-1 (sitagliptin, vildagliptin), leading to reduced appetite and weight with positive effects on metabolic control, are realistically achievable. This may be regarded as a low-risk therapeutic alternative to surgery for reducing obesity-related risk factors in the obese with lower BMIs.

Impaired adipose tissue lipid storage, but not altered lipolysis, contributes to elevated levels of NEFA in type 2 diabetes. Degree of hyperglycemia and adiposity are important factors.

BACKGROUND: Elevated levels of circulating non-esterified fatty acids (NEFA) mediate many adverse metabolic effects. In this work we aim to determine the impact of type 2 diabetes (T2D), glycemic control and obesity on lipolysis regulation. DESIGN AND PARTICIPANTS: 20 control and 20 metformin-treated T2D subjects were matched for sex (10M/10 F), age (58±11 vs 58±9 y) and BMI (30.8±4.6 vs 30.7±4.9kg/m2). In vivo lipolysis was assessed during a 3h-OGTT with plasma glycerol and NEFA levels. Subcutaneous adipose tissue (SAT) biopsies were obtained to measure mRNA and metabolite levels of factors related to lipolysis and lipid storage and to assess in vitro lipolysis in isolated subcutaneous adipocytes. RESULTS: Plasma NEFA AUC during the OGTT where higher 30% (P=0.005) in T2D than in control subjects, but plasma glycerol AUC and subcutaneous adipocyte lipolysis in vitro were similar, suggesting that adipose tissue lipolysis is not altered. Expression in SAT of genes involved in lipid storage (FABP4, DGAT1, FASN) were reduced in T2D subjects compared with controls, but no differences were seen for genes involved in lipolysis. T2D subjects had elevated markers of beta-oxidation, α-hydroxybutyrate (1.4-fold, P<0.01) and ß-hydroxybutyrate (1.7-fold, P<0.05) in plasma. In multivariate analysis, HbA1c, visceral adipose tissue volume and sex (male) were significantly associated with NEFA AUC in T2D subjects. CONCLUSIONS: In T2D subjects, NEFA turnover is impaired, but not due to defects in lipolysis or lipid beta-oxidation. Impaired adipose NEFA re-esterification or de novo lipogenesis is likely to contribute to higher NEFA plasma levels in T2D. The data suggest that hyperglycemia and adiposity are important contributing factors for the regulation of plasma NEFA concentrations.

Gastric Bypass Reduces Symptoms and Hormonal Responses in Hypoglycemia.

Gastric bypass (GBP) surgery, one of the most common bariatric procedures, induces weight loss and metabolic effects. The mechanisms are not fully understood, but reduced food intake and effects on gastrointestinal hormones are thought to contribute. We recently observed that GBP patients have lowered glucose levels and frequent asymptomatic hypoglycemic episodes. Here, we subjected patients before and after undergoing GBP surgery to hypoglycemia and examined symptoms and hormonal and autonomic nerve responses. Twelve obese patients without diabetes (8 women, mean age 43.1 years [SD 10.8] and BMI 40.6 kg/m(2) [SD 3.1]) were examined before and 23 weeks (range 19-25) after GBP surgery with hyperinsulinemic-hypoglycemic clamp (stepwise to plasma glucose 2.7 mmol/L). The mean change in Edinburgh Hypoglycemia Score during clamp was attenuated from 10.7 (6.4) before surgery to 5.2 (4.9) after surgery. There were also marked postsurgery reductions in levels of glucagon, cortisol, and catecholamine and the sympathetic nerve responses to hypoglycemia. In addition, growth hormone displayed a delayed response but to a higher peak level. Levels of glucagon-like peptide 1 and gastric inhibitory polypeptide rose during hypoglycemia but rose less postsurgery compared with presurgery. Thus, GBP surgery causes a resetting of glucose homeostasis, which reduces symptoms and neurohormonal responses to hypoglycemia. Further studies should address the underlying mechanisms as well as their impact on the overall metabolic effects of GBP surgery.

Hypoglycemia in everyday life after gastric bypass and duodenal switch.

DESIGN: Gastric bypass (GBP) and duodenal switch (DS) in morbid obesity are accompanied by marked metabolic improvements, particularly in glucose control. In recent years, episodes of severe late postprandial hypoglycemia have been increasingly described in GBP patients; data in DS patients are scarce. We recruited three groups of subjects; 15 GBP, 15 DS, and 15 non-operated overweight controls to examine to what extent hypoglycemia occurs in daily life. METHODS: Continuous glucose monitoring (CGM) was used during 3 days of normal activity. The glycemic variability was measured by mean amplitude of glycemic excursion and continuous overall net glycemic action. Fasting blood samples were drawn, and the patients kept a food and symptom log throughout the study. RESULTS: The GBP group displayed highly variable CGM curves, and 2.9% of their time was spent in hypoglycemia (<3.3  mmol/l, or 60  mg/dl). The DS group had twice as much time in hypoglycemia (5.9%) and displayed CGM curves with little variation as well as lower HbA1c levels (29.3 vs 35.9 mmol/mol, P<0.05). Out of a total of 72 hypoglycemic episodes registered over the 3-day period, 70 (97%) occurred in the postprandial state and only about one-fifth of the hypoglycemic episodes in the GBP and DS groups were accompanied by symptoms. No hypoglycemias were seen in controls during the 3-day period. CONCLUSION: Both types of bariatric surgery induce marked, but different, changes in glucose balance accompanied by frequent, but mainly unnoticed, hypoglycemic episodes. The impact and mechanism of hypoglycemic unawareness after weight-reduction surgery deserves to be clarified.

Effects of age of learning on voice onset time: categorical perception of Swedish stops by near-native L2 speakers.

This study examined the effects of age of onset (AO) of L2 acquisition on the categorical perception of the voicing contrast in Swedish word-initial stops varying in voice onset time (VOT). Three voicing continua created on the basis of natural Swedish word pairs with /p-b/, /t-d/, /k-/ in initial position were presented to 41 Spanish early (AO < 12) and late (AO > 12) near-native speakers of L2 Swedish. Fifteen native speakers of Swedish served as controls. Categorizations were influenced by AO and listener status as L1/L2 speaker, in that the late learners deviated the most from native-speaker perception. In addition, only a small minority of the late learners perceived the voicing contrast in a way comparable to native-speaker categorization, while most early L2 learners demonstrated nativelike categorization patterns. However, when the results were combined with the L2 learners' production of Swedish voiceless stops (Stölten, 2005; Stölten, Abrahamsson & Hyltenstam, in press), nativelike production and perception was never found among the late learners, while a majority of the early learners still exhibited nativelike production and perception. It is concluded that, despite their being perceived as mother-tongue speakers of Swedish by native listeners, the late learners do not, after detailed phonetic scrutiny, exhibit a fully nativelike command of Swedish VOT. Consequently, being near-native rather than nativelike speakers of their second language, these individuals do not constitute the evidence necessary to reject the hypothesis of one or several critical (or sensitive) periods for language acquisition.

GLP1 analogs as treatment of postprandial hypoglycemia following gastric bypass surgery: a potential new indication?

OBJECTIVE: The number of morbidly obese subjects submitted to bariatric surgery is rising worldwide. In a fraction of patients undergoing gastric bypass (GBP), episodes with late postprandial hypoglycemia (PPHG) develop 1-3 years after surgery. The pathogenesis of this phenomenon is not fully understood; meal-induced rapid and exaggerated increases of circulating incretins and insulin appear to be at least partially responsible. Current treatments include low-carbohydrate diets, inhibition of glucose intestinal uptake, reduction of insulin secretion with calcium channel blockers, somatostatin analogs, or diazoxide, a KATP channel opener. Even partial pancreatectomy has been advocated. In type 2 diabetes, GLP1 analogs have a well-documented effect of stabilizing glucose levels without causing hypoglycemia. DESIGN: We explored GLP1 analogs as open treatment in five consecutive GBP cases seeking medical attention because of late postprandial hypoglycemic symptoms. RESULTS: Glucose measured in connection with the episodes in four of the cases had been 2.7, 2.5, 1.8, and 1.6 mmol/l respectively. The patients consistently described that the analogs eliminated their symptoms, which relapsed in four of the five patients when treatment was reduced/discontinued. The drug effect was further documented in one case by repeated 24-h continuous glucose measurements. CONCLUSION: These open, uncontrolled observations suggest that GLP1 analogs might provide a new treatment option in patients with problems of late PPHG.

Gastric bypass surgery elevates NT-ProBNP levels.

BACKGROUND: Brain natriuretic peptide (BNP) is produced in the heart in response to stretching of the myocardium. BNP levels are negatively correlated to obesity, and in obese subjects, a reduced BNP responsiveness has been described. Diet-induced weight loss has been found to lower or to have no effect on BNP levels, whereas gastric banding and gastric bypass have reported divergent results. We studied obese patients undergoing gastric bypass (GBP) surgery during follow-up of 1 year. METHODS: Twenty patients, 18 women, mean 41 (SD 9.5) years old, with a mean preoperative BMI of 44.6 (SD 5.5) kg/m(2) were examined. N-terminal pro-brain natriuretic peptide (NT-ProBNP), glucose and insulin were measured preoperatively, at day 6 and months 1, 6 and 12. In 14 of the patients, samples were also taken at days 1, 2 and 4. RESULTS: The NT-ProBNP levels showed a marked increase during the postoperative week (from 54 pg/mL preop to 359 pg/mL on day 2 and fell to 155 on day 6). At 1 year, NT-ProBNP was 122 pg/mL (125 % increase, p = 0.01). Glucose, insulin and HOMA indices decreased shortly after surgery without correlation to NT-ProBNP change. Mean BMI was reduced from 44.6 to 30.5 kg/m(2) at 1 year and was not related to NT-ProBNP change. CONCLUSIONS: The data indicate that GBP surgery rapidly alters the tone of BNP release, by a mechanism not related to weight loss or to changes in glucometabolic parameters. The GBP-induced conversion of obese subjects, from low to high NT-ProBNP responders, is likely to influence the evaluation of cardiac function in GBP operated individuals.