Paediatric Type 2 Diabetes Still Rare in an Irish Tertiary Referral Unit.

While Type 2 Diabetes in childhood has become increasingly prevalent throughout the world, in our service we found that only 2% (7/320) of children and adolescents with diabetes aged <16 years had type 2 diabetes. All type 2 subjects were overweight or obese and six of seven were non-Caucasian. Mean age at presentation was 12.8 years. Six patients (85%) had complications, most commonly hypertension. Although Type 2 Diabetes in children remains relatively rare in our cohort, identification of these children is important as management differs from Type 1 Diabetes.

Paediatric type 1 diabetes in Ireland--results of the first national audit.

The aim of this study was to describe the services provided for children with type 1 diabetes in the Republic of Ireland, and to identify a baseline from which services and outcomes might be improved. Lead clinicians in 17 of the 19 centres providing paediatric type 1 diabetes care responded to requests for information from 2012 regarding demographics, patient numbers, diagnostics, outpatient management, multidisciplinary team resources, comorbidity screening, transition policy, clinical guidelines, and use of insulin pumps. The total number of patients attending these centres was 2518. Eight centres initiate insulin pump therapy. Insulin pump usage ranged from 0 to 42% of patients attending each centre. Self reported clinic mean haemoglobin A1c ranged from 8.2 to 9.4% (66.1 to 79.2 mmol/mol). Variation existed in guideline availability, frequency of clinic appointments, age of transition and insulin types used. We recommend a national approach to standardising and improving care for these patients.

The evolving course of HNF4A hyperinsulinaemic hypoglycaemia--a case series.

BACKGROUND: Hepatocyte nuclear factor 4 alpha (HNF4A) gene mutations have a well-recognized role in maturity-onset diabetes of the young and have recently been described in congenital hyperinsulinism. A biphasic phenotype has been postulated, with macrosomia and congenital hyperinsulinism in infancy, and diabetes in young adulthood. In this case series, we report three children with HNF4A mutations (two de novo) and diazoxide-responsive congenital hyperinsulinism, highlighting the potential for ongoing diazoxide requirement and the importance of screening for these mutations even in the absence of family history. CASE REPORTS: All patients presented with macrosomia (mean birthweight 4.26 kg) and hyperinsulinaemic hypoglycaemia soon after birth (median age 1 day). All three (age range 7 months to 11 years 10 months) remain on diazoxide therapy, with dose requirements increasing in one patient. There was no prior family history of diabetes, neonatal hypoglycaemia or macrosomia. Parents were screened for HNF4A mutations post-diagnosis and one father was subsequently found to have maturity-onset diabetes of the young. CONCLUSIONS: This case series follows the evolving course of three patients with confirmed HNF4A-mediated congenital hyperinsulinism, highlighting (1) the variable natural history of these mutations, (2) the potential for prolonged diazoxide requirement, even into adolescence, and (3) the need for screening, regardless of family history.

Short stature in child with early-onset diabetes.

We present a girl who initially presented at 12 weeks of age with antibody negative diabetes. Genetic screening for common mutations of monogenic diabetes was negative. She was noted to have short stature at 8 years of age (height <0.4 centile), as well as overlapping toes and distal abnormalities of her fingers. On reevaluation, further investigation revealed an EIF2AK3 mutation, and a diagnosis of Wolcott Rallison syndrome was made. This case highlights the importance of close follow up of patients with neonatal diabetes for the development of syndromic features that may lead to a unifying diagnosis.

Extraordinary micro-endemism in Australian desert spring amphipods.

Increasing pressure for water in the Australian arid zone is placing enormous stress on the diverse endemic communities inhabiting desert springs. Detailed information about the evolutionary processes occurring within and between individual endemic species will help to develop effective and biologically relevant management strategies this fragile ecosystem. To help determine conservation priorities, we documented the genetic structure of the endemic freshwater amphipod populations in springs fed by the Great Artesian Basin in central Australia. Phylogenetic and phylogeographic history and genetic diversity measures were examined using nuclear and mitochondrial DNA from approximately 500 chiltoniid amphipods across an entire group of springs. Pronounced genetic diversity was identified, demonstrating that levels of endemism have been grossly underestimated in these amphipods. Using the GMYC model, 13 genetically divergent lineages were recognized as Evolutionarily Significant Units (ESUs), all of which could be considered as separate species. The results show that due to the highly fragmented ecosystem, these taxa have highly restricted distributions. Many of the identified ESUs are endemic to a very small number of already degraded springs, with the rarest existing in single springs. Despite their extraordinarily small ranges, most ESUs showed relative demographic stability and high levels of genetic diversity, and genetic diversity was not directly linked to habitat extent. The relatively robust genetic health of ESUs does not preclude them from endangerment, as their limited distributions ensure they will be highly vulnerable to future water extraction.

Ghrelin prevents levodopa-induced inhibition of gastric emptying and increases circulating levodopa in fasted rats.

BACKGROUND: Levodopa (L-dopa) is the most commonly used treatment for alleviating symptoms of Parkinson's disease. However, L-dopa delays gastric emptying, which dampens its absorption. We investigated whether ghrelin prevents L-dopa action on gastric emptying and enhances circulating L-dopa in rats. METHODS: Gastric emptying of non-nutrient methylcellulose/phenol red viscous solution was determined in fasted rats treated with orogastric or intraperitoneal (i.p.) L-dopa, or intravenous (i.v.) ghrelin 10 min before orogastric L-dopa. Plasma L-dopa and dopamine levels were determined by high pressure liquid chromatography. Plasma acyl ghrelin levels were assessed by radioimmunoassay. Fos expression in the brain was immunostained after i.v. ghrelin (30 µg kg(-1)) 10 min before i.p. L-dopa. KEY RESULTS: Levodopa (5 and 15 mg kg(-1)) decreased significantly gastric emptying by 32% and 62%, respectively, when administered orally, and by 91% and 83% when injected i.p. Ghrelin (30 or 100 µg kg(-1), i.v.) completely prevented L-dopa's (15 mg kg(-1), orogastrically) inhibitory action on gastric emptying and enhanced plasma L-dopa and dopamine levels compared with vehicle 15 min after orogastric L-dopa. Levodopa (5 mg kg(-1)) did not modify plasma acyl ghrelin levels at 30 min, 1, and 2 h after i.v. injection. Levodopa (15 mg kg(-1), i.p.) induced Fos in brain autonomic centers, which was not modified by i.v. ghrelin. CONCLUSIONS & INFERENCES: Ghrelin counteracts L-dopa-induced delayed gastric emptying but not Fos induction in the brain and enhances circulating L-dopa levels. Potential therapeutic benefits of ghrelin agonists in Parkinson's disease patients treated with L-dopa remain to be investigated.

Slitrk1-deficient mice display elevated anxiety-like behavior and noradrenergic abnormalities.

Mutations in SLITRK1 are found in patients with Tourette's syndrome and trichotillomania. SLITRK1 encodes a transmembrane protein containing leucine-rich repeats that is produced predominantly in the nervous system. However, the role of this protein is largely unknown, except that it can modulate neurite outgrowth in vitro. To clarify the role of Slitrk1 in vivo, we developed Slitrk1-knockout mice and analyzed their behavioral and neurochemical phenotypes. Slitrk1-deficient mice exhibited elevated anxiety-like behavior in the elevated plus-maze test as well as increased immobility time in forced swimming and tail suspension tests. Neurochemical analysis revealed that Slitrk1-knockout mice had increased levels of norepinephrine and its metabolite 3-methoxy-4-hydroxyphenylglycol. Administration of clonidine, an alpha2-adrenergic agonist that is frequently used to treat patients with Tourette's syndrome, attenuated the anxiety-like behavior of Slitrk1-deficient mice in the elevated plus-maze test. These results lead us to conclude that noradrenergic mechanisms are involved in the behavioral abnormalities of Slitrk1-deficient mice. Elevated anxiety due to Slitrk1 dysfunction may contribute to the pathogenesis of neuropsychiatric diseases such as Tourette's syndrome and trichotillomania.

The UK case-control study of cerebral oedema complicating diabetic ketoacidosis in children.

AIMS/HYPOTHESIS: Cerebral oedema complicating diabetic ketoacidosis (DKA) remains the major cause of morbidity and mortality in children with type 1 diabetes, but its aetiology remains unknown. Our objective was to determine the impact of baseline biochemical factors and of treatment-related variables on risk of the development of cerebral oedema in children with DKA. MATERIALS AND METHODS: This was a national UK case-control study. Through the British Paediatric Surveillance Unit we identified 43 cases of cerebral oedema. Through a parallel reporting system, we also identified 2,940 episodes of DKA and selected 169 control subjects on the basis of comparable age, sex, numbers of new or known cases of diabetes and date of admission. Baseline biochemical data and treatment-related variables were extracted from the clinical notes of cases and control subjects. RESULTS: Allowing for differences in age, sex and new or known diabetes, cases were more acidotic at diagnosis of DKA (odds ratio [OR] for events in the least acidotic compared with the most acidotic tertile=0.02 [95% CI: 0.002-0.15], p<0.001). In addition, cases had higher potassium and urea levels at baseline. Calculated osmolality and baseline glucose were not significantly different. After allowing for severity of acidosis, insulin administration in the first hour (OR 12.7 [1.41-114.5], p=0.02) and volume of fluid administered over the first 4 h (OR 6.55 [1.38-30.97], p=0.01) were associated with risk. Low baseline plasma sodium and an elevated p(a)CO(2) also contributed to risk in the final regression model. Bicarbonate administration was not associated with increased risk of an event when corrected for acidosis. CONCLUSIONS/INTERPRETATION: In this case-control study of DKA, baseline acidosis and abnormalities of sodium, potassium and urea concentrations were important predictors of risk of cerebral oedema. Additional risk factors identified were early administration of insulin and high volumes of fluid. These observations should be taken into account when designing treatment protocols.

Prolonged cardiac repolarisation during spontaneous nocturnal hypoglycaemia in children and adolescents with type 1 diabetes.

AIMS/HYPOTHESIS: It has been postulated that hypoglycaemia-related cardiac dysrhythmia and, in particular, prolonged cardiac repolarisation, may contribute to increased mortality rates in children and adolescents with type 1 diabetes. METHODS: We examined the prevalence of prolonged QT interval on ECG during spontaneous hypoglycaemia in 44 type 1 diabetic subjects (aged 7-18 years), and explored the relationships between serial overnight measurements of QT interval corrected for heart rate (QTc) and serum glucose, potassium and epinephrine levels. Each subject underwent two overnight profiles; blood was sampled every 15 min for glucose measurements and hourly for potassium and epinephrine. Serial ECGs recorded half-hourly between 23.00 and 07.00 hours were available on 74 nights: 29 with spontaneous hypoglycaemia (defined as blood glucose <3.5 mmol/l) and 45 without hypoglycaemia. RESULTS: Mean overnight QTc was longer in females than in males (412 vs 400 ms, p=0.02), but was not related to age, diabetes duration or HbA(1)c. Prolonged QTc (>440 ms) occurred on 20 out of 74 (27%) nights, with no significant differences between male and female subjects, and was more prevalent on nights with hypoglycaemia (13/29, 44%) than on nights without (7/45, 15%, p=0.0008). Potassium levels were lower on nights when hypoglycaemia occurred (minimum potassium 3.4 vs 3.7 mmol/l, p=0.0003) and were inversely correlated with maximum QTc (r=-0.40, p=0.03). In contrast, epinephrine levels were not higher on nights with hypoglycaemia and were not related to QTc. CONCLUSIONS/INTERPRETATION: In young type 1 diabetic subjects, prolonged QTc occurred frequently with spontaneous overnight hypoglycaemia and may be related to insulin-induced hypokalaemia.

Nociceptin/orphanin FQ modulation of rat midbrain dopamine neurons in primary culture.

Previous microdialysis studies have identified a suppressive effect of the novel opioid peptide nociceptin (also known as orphanin FQ) on dopamine release from mesolimbic neurons. In order to further evaluate the locus of this action, we investigated nociceptin's action in an in vitro model system, namely midbrain dopamine neurons in primary culture. Immunohistochemical analysis revealed abundant tyrosine hydroxylase- and GABA-immunoreactive neurons, with a strong correlation between tyrosine hydroxylase content and basal endogenous dopamine release. Nociceptin (0.01-100 nM) suppressed basal dopamine release by up to 84% (EC50=0.65 nM). This action was reversible by drug removal and attenuated by co-application of the non-peptidergic ORL1 antagonist, Compound B. Nociceptin had no significant effect on dopamine release evoked by direct depolarization of the terminals with elevated extracellular K+, suggesting that nociceptin suppresses dopamine release by modulating the firing rate of the dopamine neurons. Nociceptin also suppressed GABA release from the cultures (45% maximal inhibition; EC50=1.63 nM). Application of the GABA-A antagonist, bicuculline, elevated extracellular dopamine concentrations but the dopamine release inhibiting property of nociceptin persisted in the presence of bicuculline. The NMDA receptor antagonist, D(-)-2-amino-5-phosphononpentanoic acid (AP-5) had no effect on basal dopamine release and failed to modify nociceptin's inhibitory effects. Thus, nociceptin potently modulates dopamine release from midbrain neurons most likely as a result of a direct suppression of dopamine neuronal activity.

Insulin lispro: a potential role in preventing nocturnal hypoglycaemia in young children with diabetes mellitus.

AIMS: The long duration of action of soluble insulin given in the evening could contribute to the high prevalence of nocturnal hypoglycaemia seen in young children with Type 1 diabetes mellitus (T1DM). We examined whether replacing soluble insulin with insulin lispro reduced this risk in children on a three times daily insulin regimen. METHODS: Open crossover study comparing insulin lispro vs. soluble insulin in 23 (16 boys) prepubertal children (age 7-11 years) with T1DM on three injections/day; long-acting isophane insulin remained identical. At the end of each 4-month treatment arm, an overnight 15-min venous sampled blood glucose profile was performed. RESULTS: Despite similar blood glucose levels pre-evening meal (lispro vs. soluble: mean +/- se 6.5 +/- 1.0 vs. 7.1 +/- 1.1 mmol/l, P = 0.5), post-meal (18.00-22.00 h) blood glucose levels were lower on insulin lispro (area under curve 138 +/- 12 vs. 170 +/- 13 mmol min-1 l-1, P = 0.03). In contrast, in the early night (22.00-04.00 h) the prevalence of low blood glucose levels (< 3.5 mmol/l) was lower on lispro (8% of blood glucose levels) than on soluble insulin (13%, P = 0.01). In the early morning (04.00-07.00 h) mean blood glucose and prevalence of low levels were no different between the two treatment groups, and fasting (07.00 h) blood glucose levels were similar (6.1 +/- 0.8 vs. 6.3 +/- 0.9 mmol/l, P = 0.8). At the end of each treatment arm there were no differences in HbA1c (lispro vs. soluble 8.6% vs. 8.4%, P = 0.3), or in insulin doses (mean, range 0.97, 0.68-1.26 vs. 0.96, 0.53-1.22 U/kg per day, P = 0.2). CONCLUSIONS: The shorter duration of action of insulin lispro given before the evening meal may reduce the prevalence of early nocturnal hypoglycaemia without compromising HbA1c in young children with T1DM.

Amplification of multiple copies of mitochondrial Cytochrome b gene fragments in the Australian freshwater crayfish, Cherax destructor Clark (Parastacidae: Decapoda).

Non-coding copies of fragments of the mitochondrial genome translocated to the nucleus or pseudogenes are being found with increasing frequency in a diversity of organisms. As part of a study to evaluate the utility of a range of mitochondrial gene regions for population genetic and systematic studies of the Australian freshwater crayfish, Cherax destructor (the yabby), we report the first detection of Cytochrome b (Cyt b) pseudogenes in crustaceans. We amplified and sequenced fragments of the mitochondrial Cyt b gene from 14 individuals of C. destructor using polymerase chain reaction (PCR) with primers designed from conserved regions of Penaeus monodon and Drosophila melanogaster mitochondrial genomes. The phylogenetic tree produced from the amplified fragments using these primers showed a very different topology to the trees obtained from sequences from three other mitochondrial genes, suggesting one or more nuclear pseudogenes have been amplified. Supporting this conclusion, two highly divergent sequences were isolated from each of two single individuals, and a 2 base pair (bp) deletion in one sequence was observed. There was no evidence to support inadvertent amplification of parasite DNA or contamination of samples from other sources. These results add to other recent observations of pseudogenes suggesting the frequent transfer of mitochondrial DNA (mtDNA) genes to the nucleus and reinforces the necessity of great care in interpreting PCR-generated Cyt b sequences used in population or evolutionary studies in freshwater crayfish and crustaceans more generally.

Acute adrenal crisis in asthmatics treated with high-dose fluticasone propionate.

Four cases of asthma (one adult, three children) developing acute adrenal crisis after introduction of high-dose inhaled fluticasone proprionate are presented. The three children, aged 7-9 yrs, had been prescribed inhaled fluticasone, dosage 500-2,000 microg x day(-1) and duration 5 months-5 yrs. All presented with convulsions due to hypoglycaemia (blood glucose 1.3-1.8 mM). The fourth case was a male of 33 yrs with difficult-to-control asthma and had been taking fluticasone propionate 1,000-2,000 microg x day(-1) for 3 yrs. He presented with fatigue, lethargy, nausea and postural hypotension. Acute adrenal crisis in each case was confirmed by investigations which included measurement of acute phase cortisol levels, short and long Synacthen stimulation tests and glucagon stimulation tests. Other cases of hypthoalamic-pituitary-adrenal axis suppression were excluded.

A comparison of morphine-induced locomotor activity and mesolimbic dopamine release in C57BL6, 129Sv and DBA2 mice.

Inbred mouse strains show marked variations in morphine-induced locomotion and reward behaviors. As increases in mesolimbic dopamine release and locomotion have been implicated as being critical aspects of drug-seeking and reward-related behaviors, the present study sought to determine the relationship between morphine-induced changes in locomotion and mesolimbic dopamine release. Freely moving microdialysis of the ventral striatum was performed in mouse strains chosen on the basis of their documented differences in locomotor and reward response to morphine (C57BL6 and DBA2) and use in the production of genetically modified mice (129Sv). Both C57BL6 and 129Sv mice showed significant increases in locomotion and ventral striatal extracellular dopamine levels following subcutaneous morphine administration (3 mg/kg), with the former strain showing the largest increase in both parameters. Ventral striatal extracellular DA levels increased in DBA2 mice to a similar extent as 129Sv mice following morphine administration, despite this strain showing no locomotor response. Intra-strain analysis found no correlation between morphine-induced locomotion and mesolimbic dopamine release in any of the strains studied. Thus, no universal relationship between morphine-induced mesolimbic dopamine release and locomotion exists between, and particularly within, inbred mouse strains. Furthermore, morphine-induced increases in mesolimbic activity correlate negatively with the rewarding potential of morphine described in previously reported conditioned place preference studies.

Local injection of pertussis toxin attenuates morphine withdrawal excitation of rat supraoptic nucleus neurones.

Morphine inhibits oxytocin neurones via G(i/o)-protein-linked mu-opioid receptors. Following chronic morphine administration oxytocin cells develop dependence, shown by withdrawal excitation after administration of the opioid antagonist, naloxone. Here, inactivation of G(i/o)-proteins by pre-treatment of morphine-dependent rats with pertussis toxin injected into the left supraoptic nucleus reduced withdrawal-induced Fos protein expression within the injected nucleus by 41+/-10% compared to the contralateral nucleus, indicating that functional G(i/o)-proteins are essential for the development and/or expression of morphine dependence by oxytocin cells in the supraoptic nucleus. In another group of rats, pertussis toxin did not alter the responses to either systemic cholecystokinin administration or systemic hypertonic saline administration, indicating that pertussis toxin does not prevent oxytocin cells from responding to stimuli that are not mediated by G(i/o)-proteins. Finally, pertussis toxin reduced acute morphine inhibition of systemic hypertonic saline-induced Fos protein expression in the supraoptic nucleus, confirming that pertussis toxin effectively inactivates G(i/o)-proteins in the supraoptic nucleus. Thus, the expression of morphine withdrawal excitation by supraoptic nucleus oxytocin cells requires the functional integrity of G(i/o)-proteins within the nucleus.

Orphanin FQ/nociceptin modulation of mesolimbic dopamine transmission determined by microdialysis.

Orphanin FQ has been reported to suppress extracellular dopamine levels in the nucleus accumbens after intracerebroventricular administration. This study sought to provide evidence for an intra-ventral tegmental site of action for this effect using a dual-probe microdialysis experimental design. Orphanin FQ was applied to the ventral tegmental area of anesthetized rats by reverse dialysis while extracellular dopamine was sampled with a second dialysis probe in the nucleus accumbens. Orphanin FQ at a probe concentration of 1 mM (but not at 0.1 mM) significantly reduced nucleus accumbens dialysate dopamine levels. The receptor-inactive analogue, des-Phe1-orphanin FQ (1 mM), produced a small but significant increase in nucleus accumbens dialysate dopamine levels. Simultaneous measurement of ventral tegmental area dialysate amino acid content revealed significant increases in both GABA and glutamate during infusion of orphanin FQ (1 mM). To determine if increased GABA overflow mediates the action of orphanin FQ on mesolimbic neurons, orphanin FQ (10 nmol) was microinjected directly into the ventral tegmental area in the presence or absence of the GABA(A) receptor antagonist, bicuculline (1 nmol). Bicuculline transiently blocked the suppressive action of orphanin FQ on accumbens dialysate dopamine levels. These data indicate that orphanin FQ decreases dopamine transmission in the nucleus accumbens by inhibiting dopamine neuronal activity in the ventral tegmental area through a mechanism that may involve an increased overflow of GABA.

Orphanin FQ/nociceptin blocks acquisition of morphine place preference.

Orphanin FQ/nociceptin (OFQ/N) suppresses the activity of the dopaminergic mesolimbic reward pathway yet reportedly fails to produce conditioned place aversion or preference. The present study sought to determine if this peptide could attenuate the development of morphine place preference. Male rats were administered OFQ/N (3 to 30 nmol intracerebroventricularly) during the induction of morphine (3 mg/kg subcutaneously) place preference. Animals receiving 3 or 10 nmol (but not 30 nmol) OFQ/N showed significant reductions in the development of place preference to morphine.

Functional relevance of the expression of ligand-induced binding sites in the response to platelet GP IIb/IIIa antagonists in vivo.

RGD-containing peptides and other antagonists of the platelet glycoprotein (GP) IIb/IIIa may induce a high-affinity binding site for fibrinogen and the expression of novel epitopes, called ligand-induced binding sites (LIBS). The functional relevance of LIBS expression in a canine model of coronary thrombolysis induced by tissue-type plasminogen activator (t-PA) was examined. Ro43-5054 (N-[N-[N-(p-amidinobenzoyl)-b-alanyl]-l-a-aspartyl]-3-phenyl-l- alanine) and Ro44-9883 ([1-(N-(p-amidinobenzoyl)-l-tyrosyl)-4-piperidinyl)oxy]acetic acid), antagonists of the GP IIb/IIIa receptor, were administered in increasing doses of 2 to 10 microg/kg/min, beginning 30 min before the infusion of t-PA. LIBS expression was determined by the binding of the monoclonal antibody, D3GP3, to platelets on exposure to Ro43-5054, Ro44-9883 and t-PA. Ro43-5054 was shown to induce LIBS, whereas Ro44-9883 and t-PA did not. Both drugs abolished platelet aggregation in response to U46619 and ADP ex vivo. Reocclusion was prevented with both Ro43-5054 and Ro44-9883, but neither drug altered reperfusion times (49 +/- 8 and 55 +/- 39 min). Both drugs increased the rate of bleeding compared with t-PA alone, but there was no difference in hemostasis between the two drugs. To determine whether the drugs differed in their effect on platelet activation in vivo, urinary 2,3-dinor-thromboxane (TX) B2, a major metabolite of TXB2, was determined by gas chromatography-mass spectrometry. After reperfusion, the urinary 2,3-dinor-TXB2 increased in the Ro43-5054-treated group, similar to control groups (32 +/- 8 and 37 +/- 9 ng/mg creatinine). This increase was blunted in the Ro44-9883-treated group (9 +/- 3 ng/mg creatinine). GP IIb/IIIa antagonists that do not induce LIBS result in a greater suppression of platelet activity but not in any discernible functional benefit in vivo.