The transCampus Metabolic Training Programme Explores the Link of SARS-CoV-2 Virus to Metabolic Disease

Currently, we are experiencing a true pandemic of a communicable disease by the virus SARS-CoV-2 holding the whole world firmly in its grasp. Amazingly and unfortunately, this virus uses a metabolic and endocrine pathway via ACE2 to enter our cells causing damage and disease. Our international research training programme funded by the German Research Foundation has a clear mission to train the best students wherever they may come from to learn to tackle the enormous challenges of diabetes and its complications for our society. A modern training programme in diabetes and metabolism does not only involve a thorough understanding of classical physiology, biology and clinical diabetology but has to bring together an interdisciplinary team. With the arrival of the coronavirus pandemic, this prestigious and unique metabolic training programme is facing new challenges but also new opportunities. The consortium of the training programme has recognized early on the need for a guidance and for practical recommendations to cope with the COVID-19 pandemic for the community of patients with metabolic disease, obesity and diabetes. This involves the optimal management from surgical obesity programmes to medications and insulin replacement. We also established a global registry analyzing the dimension and role of metabolic disease including new onset diabetes potentially triggered by the virus. We have involved experts of infectious disease and virology to our faculty with this metabolic training programme to offer the full breadth and scope of expertise needed to meet these scientific challenges. We have all learned that this pandemic does not respect or heed any national borders and that we have to work together as a global community. We believe that this transCampus metabolic training programme provides a prime example how an international team of established experts in the field of metabolism can work together with students from all over the world to address a new pandemic.

Psychosocial aspects of closed- and open-loop insulin delivery: closing the loop in adults with Type 1 diabetes in the home setting

AIMS

To explore the psychosocial experiences of closed-loop technology and to compare ratings of closed- and open-loop technology for adults with Type 1 diabetes taking part in a randomized crossover study.

METHODS

Adults (aged > 18 years) on insulin pump therapy were recruited to receive a first phase of either real-time continuous glucose monitoring with overnight closed-loop or real-time continuous glucose monitoring alone (open-loop) followed by a second phase of the alternative treatment in random order, at home for 4 weeks, unsupervised. Participants were invited to share their views in semi-structured interviews. The impact of the closed-loop technology, positive and negative aspects of living with the device overnight, along with the hopes and anxieties of the participants, were explored.

RESULTS

The participants in the trial were 24 adults with a mean (sd) age of 43 (12) years, of whom 54% were men. The mean (range) interview duration was 26 (12-46) min. Content and thematic analysis showed the following key positive themes: improved blood glucose control (n = 16); reassurance/reduced worry (n = 16); improved overnight control leading to improved daily functioning and diabetes control (n = 16); and improved sleep (n = 8). The key negative themes were: technical difficulties (n = 24); intrusiveness of alarms (n = 13); and size of equipment (n = 7). Of the 24 participant, 20 would recommend the closed-loop technology.

CONCLUSIONS

Closed-loop therapy has positive effects when it works in freeing participants from the demands of self-management. The downside was technical difficulties, particularly concerning the pump and 'connectivity', which it is hoped will improve. Future research should continue to explore the acceptability of the closed-loop system as a realistic therapy option, taking account of user concerns as new systems are designed. Failure to do this may reduce the eventual utility of new systems.

2D surface temperature measurement of plasma facing components with modulated active pyrometry

In nuclear fusion devices, such as Tore Supra, the plasma facing components (PFC) are in carbon. Such components are exposed to very high heat flux and the surface temperature measurement is mandatory for the safety of the device and also for efficient plasma scenario development. Besides this measurement is essential to evaluate these heat fluxes for a better knowledge of the physics of plasma-wall interaction, it is also required to monitor the fatigue of PFCs. Infrared system (IR) is used to manage to measure surface temperature in real time. For carbon PFCs, the emissivity is high and known (ɛ ∼ 0.8), therefore the contribution of the reflected flux from environment and collected by the IR cameras can be neglected. However, the future tokamaks such as WEST and ITER will be equipped with PFCs in metal (W and Be/W, respectively) with low and variable emissivities (ɛ ∼ 0.1-0.4). Consequently, the reflected flux will contribute significantly in the collected flux by IR camera. The modulated active pyrometry, using a bicolor camera, proposed in this paper allows a 2D surface temperature measurement independently of the reflected fluxes and the emissivity. Experimental results with Tungsten sample are reported and compared with simultaneous measurement performed with classical pyrometry (monochromatic and bichromatic) with and without reflective flux demonstrating the efficiency of this method for surface temperature measurement independently of the reflected flux and the emissivity.

Experiences of hypoglycaemia unawareness amongst people with Type 1 diabetes: A qualitative investigation

OBJECTIVES

To explore the experiences of people who have hypoglycaemia unawareness and its impact on their everyday lives.

METHODS

In-depth interviews with 38 people with Type 1 diabetes who have hypoglycaemia unawareness. Data analysis used an inductive, thematic approach.

RESULTS

Participants reported imposed and self-imposed changes to their lives following onset of hypoglycaemia unawareness including: leaving employment, curtailing pastimes and spending more time at home or being supervised by others. However, some reported getting on with life by downplaying the significance and impact of their condition, which could put their health and safety at risk. Many relied on frequent self-monitoring of blood glucose and/or prompting from others to detect hypoglycaemia. Some expressed concerns about becoming a burden on family and/or responding in irrational and aggressive ways to others' suggestions to test for and treat hypoglycaemia. Participants reported responding best to composed and directive prompts from family. Health professionals mainly advised on clinical aspects, and did not enquire about the emotional and psychosocial impact of hypoglycaemia unawareness.

DISCUSSION

Hypoglycaemia unawareness can have a profound impact on people's confidence, careers and personal relationships. Healthcare professionals should pay more attention during consultations to the emotional and social aspects of living with hypoglycaemia unawareness.

Attainment of metabolic goals in the integrated UK islet transplant program with locally isolated and transported preparations

The objective was to determine whether metabolic goals have been achieved with locally isolated and transported preparations over the first 3 years of the UK's nationally funded integrated islet transplant program. Twenty islet recipients with C-peptide negative type 1 diabetes and recurrent severe hypoglycemia consented to the study, including standardized meal tolerance tests. Participants received a total of 35 infusions (seven recipients: single graft; 11 recipients: two grafts: two recipients: three grafts). Graft function was maintained in 80% at [median (interquartile range)] 24 (13.5-36) months postfirst transplant. Severe hypoglycemia was reduced from 20 (7-50) episodes/patient-year pretransplant to 0.3 (0-1.6) episodes/patient-year posttransplant (p < 0.001). Resolution of impaired hypoglycemia awareness was confirmed [pretransplant: Gold score 6 (5-7); 24 (13.5-36) months: 3 (1.5-4.5); p < 0.03]. Target HbA1c of <7.0% was attained/maintained in 70% of recipients [pretransplant: 8.0 (7.0-9.6)%; 24 (13.5-36) months: 6.2 (5.7-8.4)%; p < 0.001], with 60% reduction in insulin dose [pretransplant: 0.51 (0.41-0.62) units/kg; 24 (13.5-36) months: 0.20 (0-0.37) units/kg; p < 0.001]. Metabolic outcomes were comparable 12 months posttransplant in those receiving transported versus only locally isolated islets [12 month stimulated C-peptide: transported 788 (114-1764) pmol/L (n = 9); locally isolated 407 (126-830) pmol/L (n = 11); p = 0.32]. Metabolic goals have been attained within the equitably available, fully integrated UK islet transplant program with both transported and locally isolated preparations.

Self-treating hypoglycaemia: a longitudinal qualitative investigation of the experiences and views of people with Type 1 diabetes

AIMS

  Despite improvements in insulin therapy, hypoglycaemia remains an inevitable part of life for many people with Type 1 diabetes. Little attention has been paid to how individuals self-treat hypoglycaemia and their likes and dislikes of clinically recommended treatments. We explored participants' experiences of self-treating hypoglycaemia after attending a structured education programme for people with Type 1 diabetes. Our aims were: to identify treatments that are acceptable to people with Type 1 diabetes; and to provide recommendations for promoting self-treatment in line with clinical guidelines.

METHODS

  Thirty adults with Type 1 diabetes were recruited from the Dose Adjustment for Normal Eating (DAFNE) programme in the UK. Study participants were interviewed post-course and 6 and 12 months later, enabling their experiences to be explored over time.

RESULTS

  Study participants described a poor knowledge of how to self-treat hypoglycaemia correctly pre-course. Post-course, individuals often struggled to adhere to clinically recommended guidelines because of: panic, disorientation, hunger sensations and consequent difficulties ingesting fixed quantities of fast-acting carbohydrate; use of sweets to manage hypoglycaemia; reversion to habituated practices when cognitive impairment as a result of hypoglycaemia supervened; difficulties ingesting dextrose tablets; and other people's anxieties about under-treatment.

CONCLUSIONS

  Historical experiences of hypoglycaemia and habituated practices can influence present self-treatment approaches. Professionals need to be aware of the range of difficulties individuals may experience restricting themselves to fixed quantities of fast-acting carbohydrate to manage hypoglycaemia. There may be merit in developing a more acceptable range of treatments tailored to people's own preferences, circumstances and needs.

Investigation of intracellular signalling cascades mediating stimulatory effect of a Gymnema sylvestre extract on insulin secretion from isolated mouse and human islets of Langerhans

AIM

Traditional plant-based remedies such as Gymnema sylvestre (GS) extracts have been used to treat diabetes mellitus for many centuries. We have shown previously that a novel GS extract, OSA®, has a direct effect on insulin secretion but its mode of action has not been studied in detail Thus this study investigated the possible underlying mechanism(s) by which OSA® exerts its action.

METHODS

The effects of OSA® on [Ca(2+)]i and K(+) conductances were assessed by Ca(2+) microfluorimetry and electrophysiology in dispersed mouse islets and MIN6 β-cells, respectively. Isolated mouse (from 20 to 25 mice) and human (from 3 donors) islets, and MIN6 β-cells, were used to investigate whether the stimulatory effect of OSA® on insulin secretion was dependent on the presence of extracellular calcium and protein kinase activation.

RESULTS

OSA ®-induced insulin secretion from mouse islets and MIN6 β-cells was inhibited by nifedipine, a voltage-gated Ca(2+) channel blocker, and by the removal of extracellular Ca(2+), respectively. OSA® did not affect the activities of KATP channels or voltage-dependent K(+) channels in MIN6 β-cells but it caused an increase in intracellular Ca(2+) ([Ca(2+)]i) concentrations in Fura-2-loaded mouse islet cells. The insulin secretagogue effect of OSA® was dependent, in part, on protein kinase activation since incubating mouse or human islets with staurosporine, a general protein kinase inhibitor, resulted in partial inhibition of OSA®-induced insulin secretion. Experiments using permeabilized, Ca(2+)-clamped MIN6 β-cells revealed a Ca(2+)-independent component action of OSA® at a late stage in the stimulus-response coupling pathway. OSA®-induced insulin secretion was unexpectedly associated with a decrease in intracellular cAMP levels.

CONCLUSIONS

These data indicate that the GS isolate OSA® stimulates insulin secretion from mouse and human islets in vitro, at least in part as a consequence of Ca(2+) influx and protein kinase activation.

Patients' experiences of adjusting insulin doses when implementing flexible intensive insulin therapy: a longitudinal, qualitative investigation

AIM

To explore patients' experiences of using flexible intensive insulin therapy, a regimen requiring them to determine and adjust quick-acting and background/basal insulin doses and mealtime ratios.

METHODS

Repeat, in-depth interviews with 30 type 1 diabetes patients converted to flexible intensive insulin therapy recruited from Dose Adjustment for Normal Eating (DAFNE) courses in the UK.

RESULTS

While patients found determination of quick acting insulin doses relatively straightforward, many struggled, over time, to determine the correct mealtime ratios and adjust basal insulin doses independently. Reasons included: lack of confidence and poor analytical skills; deferential attitudes to health professionals; worries about hypoglycaemia; and, lack of record/diary keeping resulting in fixation on current readings and failure to spot patterns and problems. When health professional support was not sought and/or record keeping neglected, patients gradually developed over-reliance on corrective doses to attain blood glucose readings within target ranges.

CONCLUSION

While patients are motivated to use flexible intensive insulin therapy, they expressed a need for on-going health professional input, particularly to support adjustment of background insulin doses and mealtime ratios. The need to sustain diary/record keeping should be emphasised to patients and provision of a dedicated glycaemic support service is recommended.

Experiences of using blood glucose targets when following an intensive insulin regimen: a qualitative longitudinal investigation involving patients with Type 1 diabetes

AIMS

Use of blood glucose targets is considered essential to help patients with Type 1 diabetes achieve tight glycaemic control following structured education. To foster effective use of blood glucose targets, we explored patients' experiences and views of implementing clinically recommended blood glucose targets after attending a structured education programme promoting intensive insulin treatment.

METHODS

Repeat, in-depth interviews with 30 patients with Type 1 diabetes recruited from Dose Adjustment for Normal Eating (DAFNE) courses in the UK. Data were analysed using an inductive, thematic approach.

RESULTS

Patients found use of blood glucose targets motivational. Targets enabled patients to identify problems with blood glucose control and prompted them to make insulin dose adjustments independently, or with assistance. However, patients tended to adapt or simplify targets over time to: make them more attainable and easy to remember; reduce risk of hypoglycaemia; and, mitigate feelings of failure when attempts to attain clinically defined targets were unsuccessful. Some patients were advised to use elevated targets to counter hypoglycaemia unawareness and required help from health professionals to determine when/if these should be reduced.

CONCLUSIONS

Although blood glucose targets are an important component of diabetes self-management, patients may adapt and personalize them over time, sometimes inadvertently, with a potentially detrimental impact on long-term glycaemic control. Blood glucose targets should be regularly revisited during clinical reviews and revised/new targets agreed to accommodate patients' concerns and difficulties. Other interventions may need to be considered to promote effective use of blood glucose targets.

Gene expression heterogeneity in human islet endocrine cells in vitro: the insulin signalling cascade

AIMS/HYPOTHESIS

Insulin secretion is a highly regulated mechanism involving a complex insulin-dependent network of communication between alpha, beta and delta cells. However, whereas the role of insulin in beta cells has been well documented, very little is known about its role in alpha and delta cells. Having recently demonstrated heterogeneity of insulin receptor (INSR) isoform expression in these three endocrine cell types, our current study aimed to characterise the expression pattern of the multiple isoforms involved in the insulin signal transduction cascade in human alpha, beta and delta cells in vitro.

MATERIALS AND METHODS

cDNA samples prepared from single human islet cells were subjected to nested PCRs.

RESULTS

Of 706 cells analysed, 15% were alpha cells, 28% beta cells, 8% delta cells and 46% non-endocrine cells. Profiling of expression of the insulin signalling cascade elements showed a heterogeneity between islet cell types, although at least one member of each protein family was expressed in the three populations of endocrine cells. Thus, the mRNAs coding for INSR-B, phosphoinositide-dependent protein kinase-1 and the human homologue of v-akt murine thymoma viral oncogene homologue 1 (AKT1) could not be detected in alpha cells, but were expressed by beta and delta cells. In addition, while the insulin receptor substrates IRS1 and IRS2, phosphoinositide-3-kinase, catalytic, beta polypeptide (PIK3CB) and AKT2 were expressed with relatively low frequencies in alpha and delta cells (<17% for IRS1, IRS2, PIK3CB; <25% for AKT2), their frequencies of expression in beta cells were 50, 33, 33 and 100%, respectively.

CONCLUSIONS/INTERPRETATION

Our results suggest that insulin signalling cascade elements in human alpha, beta and delta cells have distinct expression patterns.

ACTH stimulates insulin secretion from MIN6 cells and primary mouse and human islets of Langerhans

It has previously been suggested that ACTH and ACTH-related peptides may act as paracrine modulators of insulin secretion in the islets of Langerhans. We have, therefore, examined the expression and function of the ACTH receptor (the melanocortin 2 receptor, MC2-R) in human and mouse primary islet tIssue and in the MIN6 mouse insulinoma cell line. Mouse MC2-R mRNA was detected in both MIN6 cells and mouse islet tIssue by PCR amplification of cDNA. In perifusion experiments with MIN6 pseudo-islets, a small, transient increase in insulin secretion was obtained when ACTH(1-24) (1 nM) was added to medium containing 2 mM glucose (control) but not when the medium glucose content was increased to 8 mM. Further investigations were performed using static incubations of MIN6 cell monolayers; ACTH(1-24) (1 pM-10 nM) provoked a concentration-dependent increase in insulin secretion from MIN6 monolayer cells that achieved statistical significance at concentrations of 1 and 10 nM (150 +/- 13.6% basal secretion; 187 +/- 14.9% basal secretion, P<0.01). Similar responses were obtained with ACTH(1-39). The phosphodiesterase inhibitor IBMX (100 microM) potentiated the responses to sub-maximal doses of ACTH(1-24). Two inhibitors of the protein kinase A (PKA) signaling pathway, Rp-cAMPS (500 microM) and H-89 (10 microM), abolished the insulin secretory response to ACTH(1-24) (0.5-10 nM). Treatment with 1 nM ACTH(1-24) caused a small, statistically significant increase in intracellular cAMP levels. Secretory responses of MIN6 cells to ACTH(1-24) were also influenced by changes in extracellular Ca2+ levels. Incubation in Ca2+-free buffer supplemented with 0.1 mM EGTA blocked the MIN6 cells' secretory response to 1 and 10 nM ACTH(1-24). Similar results were obtained when a Ca2+ channel blocker (nitrendipine, 10 microM) was added to the Ca2+-containing buffer. ACTH(1-24) also evoked an insulin secretory response from primary tIssues. The addition of ACTH(1-24) (0.5 nM) to perifusions of mouse islets induced a transient increase in insulin secretion at 8 mM glucose. Perifused human primary islets also showed a secretory response to ACTH(1-24) at basal glucose concentration (2 mM) with a rapid initial spike in insulin secretion followed by a decline to basal levels. Overall the results demonstrate that the MC2-R is expressed in beta-cells and suggest that activation of the receptor by ACTH initiates insulin secretion through the activation of PKA in association with Ca2+ influx into beta-cells.

Hypoglycaemic counter-regulation at normal blood glucose concentrations in patients with well controlled type-2 diabetes

BACKGROUND

Intensive treatment to achieve good glycaemic control in diabetic patients is limited by a high frequency of hypoglycaemia. The glucose concentrations at which symptoms and release of counter-regulatory hormones takes place have not been studied in patients with well controlled type-2 diabetes.

METHODS

We studied seven well controlled, non-insulin treated, type-2 diabetic patients (mean HbA1c [corrected according to Diabetes Control and Complications Trial] 7.4%, SD 1.0) and seven healthy controls matched for age, sex, and body mass index with a stepped hyperinsulinaemic hypoglycaemic glucose clamp. Symptoms, cognitive function, and counter-regulatory hormone concentrations were measured at each glucose plateau, and the glucose value at which there was a significant change from baseline was calculated.

FINDINGS

Symptom response took place at higher whole-blood glucose concentrations in diabetic patients than in controls. Counter-regulatory release of epinephrine, norepinephrine, growth hormone, and cortisol showed a similar pattern--eg, at blood glucose concentrations of 3.8 mmol/L [SD 0.4] vs 2.6 [0.3] for epinephrine.

INTERPRETATION

Glucose thresholds for counter-regulatory hormone secretion are altered in well controlled type-2 diabetic patients, so that both symptoms and counter-regulatory hormone release can take place at normal glucose values. This effect might protect type-2 diabetic patients against episodes of profound hypoglycaemia and make the achievement of normoglycaemia more challenging in clinical practice.

Effects of glycemic control on protective responses against hypoglycemia in type 2 diabetes

OBJECTIVE

To determine the effects of glycemic control on the counterregulatory responses to hypoglycemia in type 2 diabetes.

RESEARCH DESIGN AND METHODS

Seven poorly controlled type 2 diabetes patients (mean HbA1c, 11.3 +/- 1.1%) were studied by stepped hyperinsulinemic hypoglycemic clamp (nadir, 2.4 mmol/l) before and after improving glycemic control with insulin treatment. Counterregulatory hormones, symptoms, and four-choice reaction time were measured at each glucose plateau.

RESULTS

In patients with poorly controlled type 2 diabetes, counterregulatory hormone responses began at higher plasma glucose levels than did those in healthy subjects (epinephrine, 4.4 +/- 0.2 vs. 3.7 +/- 0.2 mmol/l, P = 0.011). After significant improvement in glycemic control (mean HbA1c, 8.1 +/- 0.9%, P < 0.001) was achieved without severe hypoglycemia, hormonal responses started at much lower plasma glucose levels (e.g., epinephrine, 3.5 +/- 0.3 mmol/l, P = 0.005) and were significantly reduced in magnitude (e.g., area under epinephrine response curve, 306 +/- 93 vs. 690 +/- 107 nmol.min-1.l-1, P = 0.012). This was accompanied by a change in the plasma glucose threshold at which hypoglycemic symptoms first developed from 3.6 +/- 0.2 to 3.0 +/- 0.2 mmol/l (P = 0.019). In contrast, the plasma glucose threshold at which four-choice reaction time deteriorated did not change significantly (3.1 +/- 0.1 vs. 2.9 +/- 0.1 mmol/l, P = 0.125).

CONCLUSIONS

Counterregulatory responses begin at normoglycemia in poorly controlled type 2 diabetes. Improving glycemic control with insulin therapy normalizes hormonal responses but lowers the plasma glucose levels at which hypoglycemic symptoms develop to levels associated with impairment of four-choice reaction time, a marker of cognitive function. This process potentially increases the risk of severe hypoglycemia, but to a lesser extent than occurs in type 1 disease.

Suppression of endogenous insulin secretion regulates the rapid rise of insulin-like growth factor binding protein (IGFBP)-1 levels following acute hypoglycaemia

OBJECTIVES

Recent animal studies have suggested that insulin-like growth factor binding protein (IGFBP)-1 may regulate the insulin-like actions of the circulating IGFs. In man, IGFBP-1 levels change rapidly with nutritional status and are inversely related to changes in insulin. In-vitro studies have shown that both insulin and glucose independently regulate IGFBP-1 secretion in an inverse manner. A rapid rise of serum IGFBP-1 levels following insulin-induced hypoglycaemia suggested that glucose or glucose availability, rather than insulin, may be the major regulator of IGFBP-1.

DESIGN

Three separate experiments both in patients and in normal volunteers were designed to examine the possibility that in these extreme circumstances glucose rather than insulin was the predominant regulator of IGFBP-1.

METHODS

Insulin tolerance tests (ITT) were performed during the routine assessment of pituitary function in seven patients, four female and three male (mean age +/- SEM 36.8 +/- 6.3 years, range 20.7-69.3 years) with pituitary disease. Hypoglycaemic glucose clamp studies (insulin 2 mU/kg/min for 180 minutes) were performed in five normal volunteers, two female and three male (mean age 33.6 +/- 2.2 years, range 23.5-42.0 years). A three-part infusion study was performed in five volunteers, three female and two male (mean age 22.9 +/- 0.9 years, range 20.8-25.0 years) who received for 45 minutes on three occasions separated by at least 7 days either octreotide (long-acting somatostatin analogue) (1 microgram/min), adrenaline (3 micrograms/min) or control.

MEASUREMENTS

Serum levels of IGFBP-1, insulin, glucose, C-peptide and cortisol were measured at varying intervals during the three studies by radioimmunoassay (RIA).

RESULTS

Symptomatic hypoglycaemia (1.0 +/- 0.1 mmol/l) occurred at 30 minutes in all patients during the ITT. Serum IGFBP-1 levels rose from 28 +/- 7 to 86 +/- 15 micrograms/l at 180 minutes. During the hypoglycaemic glucose clamp study plasma glucose fell from 4.8 +/- 0.3 to 2.2 +/- 0.3 mmol/l. In contrast to the response observed during ITT, IGFBP-1 levels fell from 22 +/- 6 to 10 +/- 1 microgram/l by 180 minutes. During the octreotide infusion study there was no change in plasma glucose and plasma insulin levels fell from 5.8 +/- 1.9 to < 2.0 mU/l. Serum IGFBP-1 levels rose from 21 +/- 2 to 68 +/- 5 micrograms/l by 180 minutes. There was no change in IGFBP-1 during either the adrenaline infusion or the control study. The rise in IGFBP-1 following the octreotide infusion (68 +/- 5 micrograms/l) was similar to that in the patients undergoing the ITT (86 +/- 15 micrograms/l) (P = 0.3).

CONCLUSION

The rapid rise of serum IGFBP-1 levels induced by acute hypoglycaemia could be reproduced in euglycaemic conditions with octreotide when insulin secretion was suppressed, whereas IGFBP-1 levels did not rise with hypoglycaemia induced by a prolonged insulin infusion. These findings suggest that the surprising rise of IGFBP-1 levels observed during ITT is not secondary to changes in glucose. The rapid removal from the portal circulation of endogenous insulin with its inhibitory effect on IGFBP-1 secretion therefore appears to be the likely cause for the rapid rise of IGFBP-1 following an ITT. This conclusion supports the hypothesis that IGFBP-1 may inhibit the insulin-like actions of 'free' IGF when insulin secretion is low and so directly link the availability and hence actions of IGFs to acute but temporary changes in nutritional status.

Scientific and ethical consequences of disease prediction

HLA-typing, gene analysis, anti-islet cell antibody testing and metabolic studies can identify people at high risk for developing Type 1 (insulin-dependent) diabetes mellitus prior to the onset of clinical disease. The positive predictive value of these tests is high in first degree relatives of patients with Type 1 diabetes, but six times less so in the general population, where disease incidence is much lower but where 90% of new cases occur. Multiple testing improves sensitivity but decreases specificity. Intervention strategies are being designed with the aim of delaying or preventing progression to clinical disease. The more invasive the intervention, the greater is the specificity required. The practical and ethical implications of identifying high risk of diabetes in healthy individuals are complex and require further research, but some lessons can be learned from the experience of other disease prediction programmes.

Impairment of counterregulatory hormone responses to hypoglycemia in pregnant women with insulin-dependent diabetes mellitus

Intensive insulin therapy directed at elimination of hyperglycemia is advocated during pregnancy in women with insulin-dependent diabetes mellitus. Because such treatment is complicated by frequent hypoglycemic episodes, we evaluated maternal and fetal responses in nine intensively treated pregnant women with insulin-dependent diabetes mellitus during an insulin-induced, gradual, controlled fall in plasma glucose levels. In contrast to values in nonpregnant control women, reductions in glucose to 44 +/- 2 mg/dl in pregnant diabetic patients failed to elicit an increase in glucagon levels. Epinephrine release during hypoglycemia was also markedly suppressed in the pregnant diabetic subjects (106 +/- 32 vs 327 +/- 52 pg/ml in controls, p less than 0.001). Furthermore, the plasma glucose level at which epinephrine and growth hormone were released was 5 to 10 mg/dl lower in the pregnant women with insulin-dependent diabetes mellitus (p less than 0.05). The basal fetal heart rate remained unchanged and continued to manifest accelerations during the hypoglycemic state. We conclude that the high frequency of hypoglycemia in intensively treated pregnant women with insulin-dependent diabetes mellitus may be due in part to impaired counterregulatory hormonal responses.

Insulin resistance: an early metabolic defect of Turner's syndrome

To evaluate whether insulin resistance contributes to the increased risk of diabetes in patients with Turner's syndrome, we measured insulin sensitivity (using the euglycemic insulin clamp technique, 40 mU/m2.min) and whole body glucose and lipid oxidation (assessed by indirect calorimetry) in two groups of nondiabetic patients with Turner's syndrome and age-matched normal controls. Group 1 consisted of eight young patients (mean age, 10 +/- 0.8 yr) who had never received hormone therapy, and group 2 consisted of five patients (mean age, 17.6 +/- 1.4 yr) who had been or were on estrogen therapy. In group 2, [3-3H]glucose was also infused during the euglycemic clamp to assess hepatic sensitivity to insulin. During the euglycemic clamp, insulin-stimulated glucose metabolism was decreased in both groups of patients [group 1, 8.4 +/- 1.0 vs. 14.7 +/- 2 mM/m2.min in controls (P less than 0.05); group 2, 9 +/- 0.7 vs. 11.7 +/- 0.9 mM/m2.min in controls (P less than 0.05)]. The impairment of insulin-stimulated glucose metabolism in patients with Turner's syndrome was accounted for by reduced nonoxidative glucose disposal; glucose oxidation rose to a similar extent in Turner patients and normal controls. Insulin-induced suppression of hepatic glucose production (group 2) and plasma FFA and branched chain amino acid levels in Turner patients was also indistinguishable from that in normal controls. Our data suggest that in patients with Turner's syndrome, insulin resistance is a very early metabolic defect that may be restricted to nonoxidative pathways of intracellular glucose metabolism.

Defective free-fatty acid and oxidative glucose metabolism in IDDM during hypoglycemia. Influence of glycemic control

To examine the impact of diabetes and its treatment on plasma free-fatty acid (FFA) and oxidative fuel metabolism during hypoglycemia, we combined indirect calorimetry with [3-3H]glucose during a 4-h low-dose insulin infusion (plasma insulin approximately 2-fold above basal) in six poorly controlled and nine well-controlled insulin-dependent diabetes mellitus (IDDM) patients and in six healthy subjects. Diabetic subjects received insulin overnight to maintain euglycemia before study. Although free-insulin levels and counterregulatory hormone responses were similar, the plasma glucose fall was more pronounced in well-controlled diabetic subjects. In well-controlled diabetic and healthy subjects, the small increment in insulin rapidly suppressed plasma FFA and fat oxidation by approximately 50% and stimulated carbohydrate oxidation by approximately 80%. In contrast, plasma FFA levels did not fall in poorly controlled diabetic subjects, and glucose oxidation was not stimulated. To determine whether this resistance to the antilipolytic effect of insulin occurs in the absence of hypoglycemic counterregulation, we used a sequential low-dose euglycemic insulin clamp (0.2, 0.3, and 0.5 mU.kg-1.min-1). In healthy subjects, plasma FFA was nearly maximally suppressed at the lowest insulin dose. In contrast, plasma FFA remained persistently elevated in poorly controlled diabetic subjects at each insulin dose. However, the insulin dose-response curve for suppression of plasma FFA was near normal in well-controlled subjects. We conclude that poorly controlled IDDM diabetic patients are resistant to the antilipolytic effects of insulin and show impaired stimulation of glucose oxidation during insulin-induced hypoglycemia. Amelioration of these defects in well-controlled patients may be another factor contributing to the higher risk of hypoglycemia during intensified insulin therapy.

Angiotropic large cell lymphoma (ALCL): morphological, immunohistochemical and genotypic studies with analysis of previous reports

The entity 'angioendotheliomatosis proliferans systemisata' was first described 28 years ago as a cutaneous small vessel neoplasm of presumed endothelial origin. Since then, 101 similar cases have been reported under a variety of different names, most with systemic as well as cutaneous lesions, and a lymphoid histogenesis of the tumour cell is now favoured. Review of these cases has shown a characteristic clinical presentation with predominant neurological and dermatological features, although the diagnosis was made at autopsy in 53 per cent of patients. Most therapeutic regimens have proved ineffective with a median survival of 5 months from date of clinical presentation. Aggressive combination chemotherapy can produce complete and lasting remission and a partial response to steroids is sometimes seen. We have examined a case of this condition showing unusual clinical features. Immunohistochemical studies confirm the lymphoid origin of the tumour cells with B cell phenotype. Antigen receptor gene rearrangement studies indicate the presence of the same clonal population of B cells in multiple sites. We suggest that the term 'angioendotheliomatosis proliferans systemisata' should be dropped and support the use of 'angiotropic large cell lymphoma' to describe this unusual condition.

Deranged alpha-adrenergic regulation of growth hormone secretion in poorly controlled diabetes: reversal of the exaggerated response to clonidine after continuous subcutaneous insulin infusion

Elevated plasma growth hormone (GH) and peripheral catecholamine levels are frequently observed in poorly controlled, insulin-dependent diabetes. Since the alpha adrenergic system plays an important role in hypothalamic regulation of GH secretion, we tested the hypothesis that altered central adrenergic activity contributes to the increased GH concentrations in diabetes. Clonidine, an alpha-adrenergic agonist, was administered to nine poorly controlled, young diabetic patients (age 12-19 yr) before and after 1 wk of continuous subcutaneous insulin infusion pump therapy. As expected, continuous subcutaneous insulin infusion lowered mean 24-h plasma glucose (from 203 +/- 21 to 112 +/- 7 mg/dl, p less than 0.01) and GH (from 17.7 +/- 2.1 to 9.2 +/- 1.2 ng/ml, p less than 0.01) to values observed in normal controls. In the diabetic patients during conventional treatment, both the peak plasma GH level postclonidine (48.3 +/- 8.7 ng/ml) and the incremental area under the GH response curve (3.23 +/- 0.58 mg X min/ml) were significantly increased above normal control values (25.2 +/- 2.1 ng/ml, p less than 0.05 and 1.63 +/- 0.11 mg X min/ml, p less than 0.0025, respectively). In contrast, the GH response to clonidine was indistinguishable from normal after only 1 wk of intensified insulin treatment. Our findings support the contention that metabolic control of diabetes influences hypothalamic regulation of GH secretion and suggests that such alterations are related, at least in part, to changes in central alpha-adrenergic activity.

[Kurloff's thymic inclusion : action on rat gonads in culture]

Thymic and splenic extracts rich in FOA-KURLOFF (F.K.) body cells, obtained from guinea-pigs treated with oestrogen, were added to rat testis or ovaries in culture. Controls were prepared with extracts from thymus and spleen of non treated animals and from kidneys of treated or non treated animals. After five hours the level of sexual hormones and the germinal cells were studied. The F.K. substance has no effect on germinal cells and on progesterone and testosterone secretion. The F.K. substance induces a significative decrease of oestrogen secretion. In an other paper we established that F.K. bodies induced a hyperactivity of internal theca folliculi and of ovarian interstitial cells. It is a false image of activity in connection with a hypersecretion of FSH. The F.K. substance inhibits oestrogen synthesis.

[Neoplasm-resistance of guinea pigs: demonstration of a principle ensuring destruction of human cancer cells in culture]

The thymus and the spleen of guinea Pigs treated with oestrogen were rich in cells showing a special inclusion, the Foa-Kurloff body cell (F.K.). Thymic, spleen and renal cellular extracts were obtained by tissue crushing and ultra-centrifugation from healthy or oestrogen treated animals. The extracts were added to carcinomatous (HeLa) or to non-carcinomatous cells (MRC5 fibroblasts or foetal human lung cells). The thymic extracts in the non-treated animals and the splenic extracts rich in F.K. body cells induced an inhibition in the growth of carcinomatous cells. These effects were increased with the thymus extracts rich in F.K. bodies. The thymic inclusion of F.K. seems therefore to concentrate tumorous thymic fractions.

[Thymic Kurloff inclusion. Action on the ovogenesis of the rat]

Grafts and injections of cellular extracts from thymus and spleen of guinea pigs, were carried out in puberal and impuberal female rats. These organs are especially rich in Foa-Kurloff cells after oestrogentherapy. Kidney served as a reference material for the same experimental conditions. Controls received cellular injections and grafts from guinea pig organs without treatment. In all cases, ovarian histological and biometric study of recipient animals shows no alteration of the ovarian cycle. On the other hand, grafts and injections of cellular extracts from organs with high concentration of Foa-Kurloff cells induced hyperactivity of internal theca folliculi and of ovarian interstitial cells, only in puberal female rats.