David Neumann

New and recurrent gain-of-function STAT1 mutations in patients with chronic mucocutaneous candidiasis from Eastern and Central Europe

Background Chronic mucocutaneous candidiasis disease (CMCD) may result from various inborn errors of interleukin (IL)-17-mediated immunity. Twelve of the 13 causal mutations described to date affect the coiled-coil domain (CCD) of STAT1. Several mutations, including R274W in particular, are recurrent, but the underlying mechanism is unclear. Objective To investigate and describe nine patients with CMCD in Eastern and Central Europe, to assess the biochemical impact of STAT1 mutations, to determine cytokines in supernatants of Candida-exposed blood cells, to determine IL-17-producing T cell subsets and to determine STAT1 haplotypes in a family with the c.820C>T (R274W) mutation. Results The novel c.537C>A (N179K) STAT1 mutation was gain-of-function (GOF) for γ-activated factor (GAF)-dependent cellular responses. In a Russian patient, the cause of CMCD was the newly identified c.854 A>G (Q285R) STAT1 mutation, which was also GOF for GAF-dependent responses. The c.1154C>T (T385M) mutation affecting the DNA-binding domain (DBD) resulted in a gain of STAT1 phosphorylation in a Ukrainian patient. Impaired Candida-induced IL-17A and IL-22 secretion by leucocytes and lower levels of intracellular IL-17 and IL-22 production by T cells were found in several patients. Haplotype studies indicated that the c.820C>T (R274W) mutation was recurrent due to a hotspot rather than a founder effect. Severe clinical phenotypes, including intracranial aneurysm, are presented. Conclusions The c.537C>A and c.854A>G mutations affecting the CCD and the c.1154C>T mutation affecting the DBD of STAT1 are GOF. The c.820C>T mutation of STAT1 in patients with CMCD is recurrent due to a hotspot. Patients carrying GOF mutations of STAT1 may develop multiple intracranial aneurysms by hitherto unknown mechanisms.

Two Cases of Diabetic Ketoacidosis in HNF1A-MODY Linked to Severe Dehydration: Is it time to change the diagnostic criteria for MODY?

OBJECTIVE Hepatocyte nuclear factor-1A maturity-onset diabetes of the young (HNF1A-MODY) is a monogenic form of diabetes caused by heterozygous mutations in HNF1A. Currently, a history of diabetic ketoacidosis (DKA) is an exclusion criterion for genetic testing for MODY. HISTORY AND EXAMINATION In this article, we describe two unrelated patients aged 17 and 24 years with severe DKA developed several years after the diagnosis of HNF1A-MODY. INVESTIGATION Both patients were treated with insulin, but their metabolic control was poor (HbA1c 15%, 140 mmol/mol and 13%, 119 mmol/mol, respectively) due to noncompliance and missed insulin injections. In both patients, DKA followed a course of recurrent vomiting with dehydration and prerenal acute kidney injury. Their glycemia, blood pH, and base excess at admission were 97 mmol/L [1,748 mg/dL], 6.80, and −33 mmol/L (patient 1) and 34 mmol/L [613 mg/dL], 7.03, and −14 mmol/L (patient 2). CONCLUSIONS This anecdotal observation supports the notion that a history of DKA does not exclude MODY.

Preparation of pellets with controlled release of glucose as prevention of hypoglycaemia in paediatric patients.

Hypoglycaemic episodes represent serious and frequent complications of type 1 and 2 diabetes. Theoretically, the risk of hypoglycaemic states can be affected by a dosage form based on a food supplement containing a delayed release formulation of glucose. The release of glucose should compensate for balance the peak effect of an antidiabetic treatment. In clinical practice, a diet with fibre and grains is recommended and patients are broadly educated in the topic of low and high glycaemic indexes to achieve the same effect. However, a precisely-timed release of carbohydrates can favourably target expected hypoglycaemia and concurrently decrease carbohydrate content. To study the possibility of preparing the dosage form with controlled-release carbohydrates, a dosage form of pellets containing four osmotically active substances coated by a membrane created of ethylcellulose was prepared. These pellets can be administered in a mixture with liquid or semisolid food. The resulting dissolution profiles for selected compositions showed that delayed release can be achieved for 120, 240 and 360min in vitro, representing an ideal delay for clinical purposes.

Coated pellets with delayed-release glucose for prevention of hypoglycemic episodes.

Abstract Patients tend to prevent hypoglycemia by excessive saccharide intake leading to poorer glycemic control with potentially fatal consequences. This problem could be resolved by means of pellets with glucose release delayed by 120–360 min as a compensation of the antidiabetic drug peak effect. No glucose is released before; hence there is no risk of hyperglycemia and secondary complications. The pellets contain glucose in combination with an osmotically active ingredient and are coated with an ethylcellulose dispersion, which forms an insoluble semipermeable membrane and ensures delayed release. The release of glucose was assessed using dissolution and high-performance liquid chromatography. Dissolution profiles indicated the possibility of achieving the requested lag time using a combination of adequate compositions and coating concentrations. Lag times of 60, 240 and 360 min were achieved. The sample containing carboxymethyl starch was found to be most suitable for the intent of this work.

Interdiction of hypoglycemia in diabetic children by multiparticulate dosage form with controlled glucose release.

Abstract Patients tend to evade the occurrence of hypoglycemic episodes by excessive carbohydrate intake. Glucose pellets with delayed release in the time of the maximum effect of insulin can not only prevent hypoglycemia but also eliminate the preventive carbohydrate intake. The pellets can be administered in a mixture with semisolid food. The cores containing glucose in combination with osmotically active agents (croscarmellose sodium, carmellose sodium, polyethylene glycol, or carboxymethyl starch) were prepared by extrusion–spheronization and coated with 15% water ethylcellulose dispersion (Surelease® B NF) in Wurster column (Medipo, Havlíčkův Brod, Czech Republic) into four coating levels (12.5, 25, 35, and 50%). Mean particle size is 0.63–0.73 for cores and 0.82–0.98 for coated pellets. Cores and coated pellets have excellent or good flow properties according to Hausner ratio and Carr index. Aspect ratio ranges from 1.78 to 2.17 for cores and from 1.73 to 2.31 for coated pellets. Dissolution was performed using pH-independent method and method with continual change of pH. The suitable pH-independent release was achieved in the samples containing carboxymethyl starch or polyethylene glycol. Glucose release is enabled by a membrane rupture caused by core swelling. It can be, therefore, assumed that the glucose release profile will not be affected by food or transit time.

Urinary iodine concentrations in mothers and their term newborns in country with sufficient iodine supply

Abstract Objective: The main aim of the study was to evaluate maternal and newborn urinary iodine concentrations according to the usage of iodine supplementation during pregnancy. Methods: Thirty-seven women with singleton uncomplicated pregnancies and their newborns were included in this study. Maternal urine samples were obtained at the time of delivery and on the third day after delivery. Newborn urine samples were obtained on the third day after delivery. Urinary iodine concentrations were determined by the alkaline ashing of urine specimens followed by the Sandell–Kolthoff reaction using brucine as a colorimetric marker. Result: The overall rate of the usage of iodine supplementation during pregnancy was 54% (20/37). Women who used the iodine supplementation during the pregnancy did not have different urinary iodine concentrations neither at the time of delivery (p = 0.23), nor on the third day after delivery (p = 0.65) in comparison to women without extra iodine supplementation. Newborns from pregnancies with regular iodine supplementation had higher urine iodine concentrations on the third day after delivery (p = 0.02). When women were split into several subgroups based on the daily dosage of iodine supplementation (200, 150, and 50 μg daily and without iodine supplementation), no differences were found in maternal urine iodine concentrations at the time of delivery (p = 0.51) and on the third day after delivery (p = 0.63). Different levels were found in newborn urine iodine concentrations among the subgroups of newborns from pregnancies with different daily doses of iodine supplementation and from pregnancies without iodine supplementation during pregnancy (p = 0.05). Conclusions: Iodine supplementation during pregnancy affects newborn urine concentrations but not maternal urine concentrations.

Dominant-negative STAT5B mutations cause growth hormone insensitivity with short stature and mild immune dysregulation

Growth hormone (GH) insensitivity syndrome (GHIS) is a rare clinical condition in which production of insulin-like growth factor 1 is blunted and, consequently, postnatal growth impaired. Autosomal-recessive mutations in signal transducer and activator of transcription (STAT5B), the key signal transducer for GH, cause severe GHIS with additional characteristics of immune and, often fatal, pulmonary complications. Here we report dominant-negative, inactivating STAT5B germline mutations in patients with growth failure, eczema, and elevated IgE but without severe immune and pulmonary problems. These STAT5B missense mutants are robustly tyrosine phosphorylated upon stimulation, but are unable to nuclear localize, or fail to bind canonical STAT5B DNA response elements. Importantly, each variant retains the ability to dimerize with wild-type STAT5B, disrupting the normal transcriptional functions of wild-type STAT5B. We conclude that these STAT5B variants exert dominant-negative effects through distinct pathomechanisms, manifesting in milder clinical GHIS with general sparing of the immune system.Severe growth hormone insensitivity syndrome (GHIS) with immunodeficiency is caused by autosomal recessive mutations in STAT5B. Here the authors report heterozygous STAT5B mutations with dominant-negative effects, causing mild GHIS without immune defects.

Neurophysiological Evidence for a Compensatory Activity during a Simple Oddball Task in Adolescents with Type 1 Diabetes Mellitus

Objective The poor metabolic control in type 1 diabetes mellitus (T1D) has a negative impact on the developing brain. Hyperglycemia and glycemic fluctuations disrupt mainly executive functions. To assess a hypothesized deficit of the executive functions, we evaluated visual processing and reaction time in an oddball task. Methods Oddball visual event-related potentials (ERPs), reaction time, and pattern-reversal visual evoked potentials (VEPs) were examined in a cohort of twenty-two 12- to 18-year-old T1D patients without diabetic retinopathy at normal glycemia and in nineteen 10- to 21-year-old healthy controls. Results The P100 peak time of the VEPs was significantly prolonged in T1D patients compared with the control group (p < 0.017). In contrast to the deteriorated sensory response, the area under the curve of the P3b component of the ERPs was significantly larger (p = 0.035) in patients, while reaction time in the same task did not differ between groups (p = 0.713). Conclusions The deterioration on a sensory level, enhanced activity during cognitive processing, and balanced behavioral response support the view that neuroplasticity counterbalances the neural impairment by enhanced cognitive processing to achieve normal behavioral performance in T1D adolescents.

Clinical assessment of the lag-time and tmax of pellets with controlled release of glucose: in-vitro/in-vivo comparison using 13C-breath test

Maintaining a stable glycaemia in diabetes mellitus type 1 requires flexible insulin administration and carbohydrate intake to affected individuals. In real life, there might be some situations limiting the insulin–sugar balance control, e.g. night sleep or prolonged sporting activities. Glucose pellets with a pre‐determined time lag between the pellet administration and glucose release were developed to mimic a ‘snack eaten in advance’. In this article, a 13C–glucose breath test was introduced to translate laboratory dissolution testing to clinical confirmation of the glucose release pattern using 5% δ abundance to differentiate the appearance of in 13C exhaled breath. An independent two‐sample t‐test (p = 0.20) confirmed an average clinical lag time of 300 min and an in vitro time of 338 min to be identical at a level of significance of α = 0.05. Moreover, using the same statistical method, the clinical tmax (564 min) and the in vitro t50 (594 min) were also considered identical (p = 0.34). It was concluded that dissolution testing is a relevant method to determine the time lags of dosage forms with controlled release of glucose and that the 13C–glucose breath test is a suitable clinical tool for lag time verification in clinical studies.