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.

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.

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.

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.

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.

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.

Intracerebroventricular orphanin FQ/nociceptin suppresses dopamine release in the nucleus accumbens of anaesthetized rats.

Cloning studies have identified a novel seven transmembrane receptor displaying high sequence homology to the three classical opioid receptors (mu, delta and kappa). This receptor is widely distributed throughout the CNS. 1 Recently, an endogenous ligand for this receptor was isolated (termed either "orphanin FQ" or "nociceptin") and identified as a heptadecapeptide showing sequence homology with the endogenous opioids. Surprisingly, in contrast to known opioids, orphanin FQ displays hyperalgesic rather than analgesic properties. Furthermore, in contrast to enkephalins and endorphins, but similarly to dynorphins, this peptide has inhibitory actions upon locomotor activity. These preliminary data suggest that orphanin FQ systems may act in an opposing manner to the previously well-described enkephalin and endorphin systems. Since numerous studies have implicated activation of the mesolimbic dopamine pathway to be central to the rewarding actions of opiates such as morphine and heroin, as well as several other abused drugs, and also to mediate the hyperlocomotory action of such drugs, we sought to determine the effect of orphanin FQ on this pathway. In accordance with the inhibitory effect of this peptide on locomotor activity, we now report that orphanin FQ suppresses dopamine release in the nucleus accumbens in a dose-dependent manner, providing the first neurochemical evidence for a modulatory role of this recently described peptide in the CNS.

The role of afferent inputs to supraoptic nucleus oxytocin neurons during naloxone-precipitated morphine withdrawal in the rat.

During prolonged exposure to morphine, oxytocin neurons of the rat supraoptic nucleus develop dependence, shown by hyperexcitation following morphine withdrawal. The present study investigated the role of afferent projections to the supraoptic nucleus in this withdrawal excitation. Rats were made morphine-dependent by continuous intracerebroventricular infusion of morphine at increasing doses (up to 50 microg/h). On the sixth day, rats were anaesthetized with pentobarbitone and morphine withdrawal was precipitated by intraperitoneal injection of naloxone (5 mg/kg). Fos-immunoreactivity in the supraoptic nucleus, and also in the median preoptic nucleus, organum vasculosum of the lamina terminalis and subfornical organ, which project to the supraoptic nucleus, increased following morphine withdrawal. However, retrograde tracing from the supraoptic nucleus showed that, of the neurons in these regions which project to the supraoptic nucleus, only 0.4-7.1% expressed Fos in response to morphine withdrawal. Following morphine withdrawal, Fos-immunoreactivity was present in 39.2% and 19.8% of the tyrosine hydroxylase-immunoreactive neurons of the A1/C1 and A2/C2 cell groups. Of the cells in these regions identified as projecting to the supraoptic nucleus, 11.3% in the region of the A2 cell group and 12.7% in the region of the A1 cell group expressed Fos after morphine withdrawal. In a second study, monoamine release was measured in the supraoptic nucleus of urethane-anaesthetized morphine-dependent and -naive rats. Retrodialysis of naloxone (10[-5] M) into the supraoptic nucleus induced a small increase in plasma oxytocin concentration in morphine-dependent rats (13.5+/-4.8 pg/ml increase) but not in naive rats (1.2+/-5.9 pg/ml decrease), with no significant change in monoamine release in either morphine-dependent or -naive rats. Intravenous injection of naloxone (5 mg/kg) 1 h later produced a further significant increase in plasma oxytocin concentration in morphine-dependent rats concomitant with a significant increase in noradrenaline release from the supraoptic nucleus. Thus, morphine-withdrawal excitation of supraoptic oxytocin neurons occurs concurrently with a modestly increased activity of their input from the brainstem, and very little activation in other known inputs.

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.

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.

The effect of calcium channel antagonists on the release of [3H]noradrenaline in the human neuroblastoma, SH-SY5Y.

The effect of calcium channel antagonists on depolarization and carbachol evoked release of [3H]noradrenaline in the human neuroblastoma, SH-SY5Y, was investigated. Nifedipine, verapamil and diltiazem completely inhibited the depolarization evoked release of [3H]noradrenaline with IC50 values of 0.44 +/- 0.1 microM, 3.6 +/- 0.24 microM and 5.6 +/- 0.2 microM respectively. In addition, nickel, cobalt and cadmium, all at 2 mM, inhibited depolarization evoked release by 89.2 +/- 2.3%, 72.6 +/- 1.6% and 102.5 +/- 1.4% respectively. Furthermore, omega-conotoxin resulted in at least 20% inhibition of potassium evoked release, suggesting a role of N-type calcium channels. Carbachol evoked release of [3H]noradrenaline was inhibited by 10(-4) M nifedipine, diltiazem and verapamil by 15.6 +/- 1.1%, 14.6 +/- 3.2% and 23.6 +/- 1.8% respectively and by 2 mM nickel, cobalt and cadmium by 13.8 +/- 3.2%, 34 +/- 2.1% and 6.5 +/- 3.7% respectively. These results suggest that depolarization evoked release of [3H]noradrenaline is mediated via L- and N-type calcium channels, whereas, carbachol evoked release does not appear to be coupled an L-, T- or N-type voltage sensitive calcium channel.

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.

Opioid-noradrenergic interactions in the control of oxytocin cells.

The nucleus tractus solitarii (NTS) projects directly to the oxytocin neurones of the supraoptic nucleus (SON), and relays afferent stimuli arising from the birth canal during parturition. About 80% of these projecting neurones are noradrenergic, and these same neurones are activated following systemic administration of cholecystokinin (CCK), which also results in an increased electrical and secretory activity in oxytocin neurones. Oxytocin release in response to CCK is abolished following selective neurotoxic destruction of these noradrenergic neurones. Oxytocin release following CCK (and that during parturition) is potently inhibited by morphine, which blocks the local noradrenaline release in the supraoptic nucleus. This acute opiate action involves presynaptic inhibition of the noradrenergic terminals, and occurs without marked suppression of the activity of noradrenergic cells in the NTS. During chronic exposure to morphine the oxytocin system becomes tolerant to, and dependent upon morphine. In the course of tolerance, oxytocin cell activation in response to CCK recovers from initial inhibition. However, the pathway that mediates this response does not appear to become dependent: the oxytocin cell response to CCK is unchanged by opiate withdrawal induced by naloxone, despite a large increase in the background electrical activity of oxytocin cells provoked by withdrawal. Nevertheless, expression of withdrawal excitation by oxytocin neurones is curiously contingent upon the activity of the noradrenergic input in that prior lesioning of this input has no effect upon the subsequent withdrawal excitation of oxytocin cells. Yet under urethane anaesthesia, acute pharmacological blockade of the noradrenergic input suppresses withdrawal. We discuss how these paradoxical observations might be reconciled, and note that the difference may be related to differing levels of tonic activity in the noradrenergic input. It is possible that dependence relies upon the input when it is there, but not when it is not.

Benign intracranial hypertension following severe hyponatremic dehydration in congenital adrenal hyperplasia.

A case of salt-losing congenital adrenal hyperplasia with severe hyponatremic dehydration is presented. Clinical signs and symptoms of cerebral edema with elevated intracranial pressure were present. Conventional treatment was started, and after initial concern regarding future head growth and development, there was a good outcome with normal development at 1 year of age. This course is suggestive of benign intracranial hypertension. Possible mechanisms are discussed with a review of the relevant literature.

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.

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.