[Frequency and influencing factors of ketoacidosis at diabetes onset in children and adolescents--a long-term study between 1995 and 2009]. / Häufigkeit und Einflussfaktoren der Ketoazidose bei Diabetesmanifestation im Kindes- und Jugendalter--eine Langzeitstudie von 1995 bis 2009.

BACKGROUND: Diabetic ketoacidosis (DKA) is a frequent acute complication at onset of type 1 diabetes. It is assumed that increased public awareness about diabetes symptoms may reduce DKA rate at diabetes onset. To investigate the time-dependent trend in DKA prevalence we analysed the frequency and determinants of DKA at disease onset over 15 years in pediatric patients. PATIENTS AND METHODS: The prevalence of DKA at disease onset was analysed in individuals aged ≤18 years treated for the first time from 1995-2009 within 7 days after diagnosis in pediatric centers. Simple and multiple logistic regression analysis was performed to investigate influencing factors on DKA prevalence. Change of the probability of ketoacidosis over years were modelled in the logistic regression as linear trend. RESULTS: 16 562 individuals from 170 institutions were studied with a mean age of 9.2 ± 4.2 years. DKA (pH <7.3) was present in 20.8% of patients without a significant trend between 1995 and 2009 (p=0.222). DKA prevalence was higher in children ≤5 years (26.3%) and in the age group 10-15 years (21.7%) than in individuals aged 5-10 years (16.4%) and 15-18 years (16.9%, p<0.001). Girls had DKA more often than boys (21.2% vs. 19.3%, p=0.002). DKA frequency was increased in individuals with migration background (26.5% vs. 19.2%, p<0.001). CONCLUSIONS: DKA prevalence at diabetes onset was constant at about 21% during the last 15 years. Very young children, pubertal adolescents, girls and individuals with migration background are at higher risk for DKA at diagnosis. To prevent DKA earlier diagnosis of type 1 diabetes is warranted especially in these patient groups.

Identification of the autophosphorylation sites and characterization of their effects in the protein kinase DYRK1A.

Protein kinases of the DYRK ('dual-specificity tyrosine-regulated kinase') family are characterized by a conserved Tyr-Xaa-Tyr motif (Tyr-319-Tyr-321) in a position exactly corresponding to the activation motif of the mitogen-activated protein kinase (MAP kinase) family (Thr-Xaa-Tyr). In a molecular model of the catalytic domain of DYRK1A, the orientation of phosphorylated Tyr-321 is strikingly similar to that of Tyr-185 in the known structure of the activated MAP kinase, extracellular-signal-regulated kinase 2. Consistent with our model, substitution of Tyr-321 but not of Tyr-319 by phenylalanine markedly reduced the enzymic activity of recombinant DYRK1A expressed in either Escherichia coli or mammalian cells. Direct identification of phosphorylated residues by tandem MS confirmed that Tyr-321, but not Tyr-319, was phosphorylated. When expressed in COS-7 cells, DYRK1A was found to be fully phosphorylated on Tyr-321. A catalytically inactive mutant of DYRK1A contained no detectable phosphotyrosine, indicating that Tyr-321 is autophosphorylated by DYRK1A. MS identified Tyr-111 and Ser-97 as additional autophosphorylation sites in the non-catalytic N-terminal domain of bacterially expressed DYRK1A. Enzymic activity was not affected in the DYRK1A-Y111F mutant. The present experimental data and the molecular model indicate that the activity of DYRK1A is dependent on the autophosphorylation of a conserved tyrosine residue in the activation loop.

Operative treatment of a congenital pancreatic pseudocyst: a case report.

Congenital pancreatic pseudocysts are very rare and have so far been described in only 4 cases. We report on a patient with a congenital pancreatic pseudocyst diagnosed only intraoperatively. We show with this case that diagnosis is difficult. Furthermore, we show the histology and operation method.

Bronchiolitis obliterans organizing pneumonia: a distinct pulmonary complication in cystic fibrosis.

Organizing pneumonia in cystic fibrosis has hitherto been considered a nonspecific reparative process. We report on an adult patient with cystic fibrosis and histologically proven bronchiolitis obliterans organizing pneumonia, who experienced sustained clinical improvement under corticosteroid therapy. This case suggests that bronchiolitis obliterans organizing pneumonia may be a distinct pulmonary complication in cystic fibrosis and improve with specific therapy.

[Minibrain/DYRK1A gene: candidate gene for mental retardation in Down's syndrome?]. / Minibrain/DYRK1A-Gen: Kandidatengen für die mentale Retardierung bei Down-Syndrom?

DYRK1A is the first member of a novel subfamily of protein kinases with dual specificity. The human gene for DYRK1A is located in the "Down syndrome critical region" (21q22.2). Due to its relationship to the Drosophila gene minibrain (Mnb), whose mutation results in specific defects in neurogenesis, and based on functional experiments on transgenic mice, DYRK1A is discussed as a candidate gene for mental retardation in Down syndrome. The kinase is characterized by its ability to catalyze tyrosine-directed autophosphorylation as well as phosphorylation of serine/threonine residues in substrates. Its exact cellular function is yet unknown. DYRK1A is, however, known to be translocated into the nucleus and supposed to be involved in the control of cell growth and development. The pathogenetic impact of DYRK1A on Down syndrome needs further elucidation.

Effect of cisapride on acid gastro-oesophageal reflux during treatment with caffeine.

About 50% of preterm infants and neonates receiving methylxanthines for respiratory stimulation will develop a pathological gastro-oesophageal reflux (GOR) pattern. In the face of potential GOR-related complications the effect of a concomitant treatment with a prokinetic agent, such as cisapride, should be evaluated. In this study 32 formerly preterm infants were studied simultaneously by 24-hour oesophageal pH monitoring and cardio-respirogram before the presumed end of caffeine treatment. In 14 of these infants a reflux index (RI; percentage of recording time) of more than 4% could be detected (pH <4). Ten of them were treated orally with cisapride (0. 2 mg/kg t.i.d.). Data of pH monitoring, cardio-respirogram and caffeine serum concentrations were obtained before and 5 days after introducing cisapride. The RI and the frequency of GOR decreased significantly with cisapride. The steady-state serum concentrations of caffeine were not influenced by cisapride and the extent of periodic breathing remained unchanged. In conclusion, cisapride has a positive influence on GOR parameters during caffeine treatment without impairing the oral bioavailability or therapeutic effect of caffeine.

Neonatal diabetes mellitus with hypergalactosemia.

We report the case of a male, small-for-gestational-age newborn who presented with failure to thrive, severe fluctuation of blood glucose concentrations, and increased serum concentrations of galactose. The infant responded well to a lactose-free diet supplemented with fructose, inulin and corn starch. The metabolic disorder disappeared within 6 months. The transient course, and results of a molecular analysis of the glucose transporter 2 (Glut2) gene seem to rule out Fanconi-Bickel syndrome.

Pneumonectomy in cystic fibrosis.

A 17-year-old boy and a 12-year-old girl with cystic fibrosis (forced expiratory volume in 1 sec, 36% and 14% of predicted values, respectively) developed severe right-sided lung infections with abscess formations and complete atelectases unresponsive to medical therapy. In both patients, unilateral emergency pneumonectomy resulted in rapid clinical improvement. Despite her severe underlying lung disease, the girl experienced a remarkable increase in quality of life; 2 years after surgery, she died from respiratory failure. The male patient has now survived for 4 years, and lung transplantation still remains a therapeutic option for him. We believe that pneumonectomy is a valuable rescue therapy for patients with cystic fibrosis and intractable unilateral lung infections who are at high risk of dying while waiting for lung transplantation.

Efficacy and safety of acarbose in patients with cystic fibrosis and impaired glucose tolerance.

UNLABELLED: Impaired glucose tolerance (IGT) is an increasingly frequent complication of cystic fibrosis (CF). In CF patients, a fast postprandial rise in plasma glucose is typically followed by a delayed but prolonged insulin response. Patients may develop symptoms of both hyper- and hypoglycaemia. The alpha-glucosidase inhibitor, acarbose, delays the hydrolysis and subsequent absorption of ingested carbohydrates. The aim of this study was to investigate the efficacy of acarbose in CF patients with IGT. During a 2-week inpatient period for treatment of Pseudomonas infection, 12 CF patients with IGT were studied in a double-blinded, randomized crossover trial. Each patient received acarbose (50 mg t.i.d.) for 5 days and placebo for 5 days (days 3-8 and days 10-14, respectively). Glucose, insulin and C-peptide responses to a standardized nutritional load were measured at baseline and at the end of each study period (Days 2, 8 and 14). Treatment with acarbose was associated with significant reductions in the mean value, mean peak values and the area under the curve of plasma glucose, insulin and C-peptide, compared to respective baseline values and placebo. Gastro-intestinal disturbances were recorded in 67% of patients during therapy with acarbose. CONCLUSION: Acarbose has a positive therapeutic effect on glucose tolerance in cystic fibrosis patients, as shown by attenuation of postprandial plasma glucose increase and a significant decrease in insulin secretion response. However, acarbose treatment was associated with adverse gastro-intestinal effects that may prevent patients from accepting long-term therapy.

GH transcription factors.

The pituitary transcription factor Pit-1 is expressed during the later differentiation stages of anterior pituitary development and Pit-1 mutations have been identified as the cause of a combined pituitary hormone deficiency (CPHD) for GH, prolactin and TSH. Mutations within the human Pit-1 gene can either impair the DNA binding of this transcription factor, or while leaving DNA binding capabilities unimpaired, decrease its function within the transactivation complex. Approximately half of all patients with this phenotype do not show any defect within the Pit-1 gene. Prop-1, a recently discovered transcription factor of anterior pituitary development, seemed a likely candidate for such mutations. Prop-1 mutations, however, have been found so far to induce a combined pituitary hormone deficiency for GH, prolactin, TSH and gonadotropins. We describe here a group of patients with isolated and combined pituitary hormone deficiencies who were screened for Pit-1 and Prop-1 mutations to characterize the phenotypic spectrum of defects within these two genes.

Combined pituitary hormone deficiency: role of Pit-1 and Prop-1.

During fetal development of the anterior pituitary gland, a number of sequential processes occur that affect cell differentiation and proliferation. Molecular analyses have revealed several steps that are required for pituitary cell line specification and have identified specific factors that control these steps. The gene encoding the pituitary transcription factor 1 (Pit-1) is expressed during differentiation steps that take place quite late in the development of the anterior pituitary gland. Clinically, patients with mutations of the PIT1 gene are characterized by severe deficiencies in growth hormone (GH) and prolactin (PRL), and often develop secondary hypothyroidism. A second pituitary transcription factor is known as Prophet of Pit-1 (Prop-1), and a mutation of the Prop1 gene has been detected in Ames dwarf mice. Several Prop1 mutations have been identified that structurally affect the 'paired-like' DNA-binding domain of the Prop-1 protein molecule. Patients with PROP1 mutations show combined pituitary hormone deficiency. These patients exhibit secondary hypogonadism in addition to the deficiencies of GH, PRL and thyroid-stimulating hormone (TSH) also seen in patients with PIT1 mutations. Although all are in the subnormal range, the levels of GH, PRL and TSH in patients with PROP1 mutations are, on average, slightly higher than in patients with PIT1 mutations. Some degree of hypocortisolism may necessitate cortisol substitution in patients with PROP1 mutations.

[Lipoma of the corpus callosum in a newborn infant: misinterpretation of cranial ultrasound by coincidence with thrombocytopenia]. / Lipom des Corpus callosum bei einem Neugeborenen: Fehlinterpretation der Schädelsonographie durch Koinzidenz mit Thrombopenie.

Among the very rare intracerebral lipomas, those of the corpus callosum are the most frequent. Due to the advanced technology and the frequent use of ultrasonography these lesions are diagnosed more and more often. A female neonate was admitted to our hospital because of a progressive thrombocytopenia. Pregnancy was complicated by an autoimmune thrombocytopenia of the mother. While there were no remarkable findings on clinical presentation, a sonogram of the brain revealed an area of increased echogenicity in the midline which was interpreted as an intracerebral hemorrhage. In absence of any respective clinical signs a magnet-resonance-tomography of the brain was performed leading to the hypothesis of a lipoma of the corpus callosum (LCC) that could be verified by a densitometry in a cranial computer tomography (CT). Obviously, the initially performed sonogram was misinterpreted as an intracerebral hemorrhage due to the coincidence with the thrombocytopenia. At last the discrepancy of clinical and ultrasonographical findings led to the diagnosis by magnet-resonance-tomography and CT scan. Knowledge of the typical sonographic appearance of an LCC may be helpful for the differential diagnosis of this rare lesion even in fetal ultrasound.

cDNA cloning and characterization of rat Clk3, a LAMMER kinase predominately expressed in testis.

A cDNA clone of a protein kinase with high similarity to the Clk (Cdc2-like kinases) subfamily was isolated from a rat brain library and characterized. Its deduced amino acid sequence exhibited a 99% identity with human Clk3 and was therefore designated rat Clk3. In addition to the protein kinase domain, the sequence (490 amino acids) comprises an N-terminal domain with a strikingly high portion of basic amino acids. A glutathione S-transferase fusion protein of Clk3 catalyzed autophosphorylation of the kinase but not phosphorylation of the exogenous substrates histone or casein. By Northern blot analysis of different rat tissues, mRNA of Clk3 was detected predominately in testis, suggesting that this kinase regulates a predominately testicular function.

Molecular cloning and characterization of a novel mammalian protein kinase harboring a homology domain that defines a subfamily of serine/threonine kinases.

The cDNA of a novel protein kinase (referred to as SNRK) was isolated from a rat fat cell cDNA library with a probe generated by a cloning approach based on the polymerase chain reaction. The encoded polypeptide (746 amino acids, Mr=81627) contains all conserved subdomains characteristic of the protein serine/threonine kinase family. A recombinant fusion protein with glutathione S-transferase catalysed autophosphorylation as well as phosphorylation of histone, confirming that SNRK has indeed protein kinase activity. By Northern blot hybridization, a 5-kb mRNA was detected in brain, heart, fat cells, intestine, testis, ovary, adrenal gland and thymus. In 3T3-L1 cells. SNRK was specifically expressed in the differentiated, adipocyte-like phenotype, whereas its mRNA was not detected in fibroblasts. Sequence comparisons of its catalytic domain relate SNRK to the SNF1 family of protein kinases. The noncatalytic domain comprises several intriguing structural features, including a glycine-rich region, two PEST sequences, and a bipartite nuclear localization signal which is preceded by a stretch of ten consecutive acidic residues. This part of the sequence exhibits no extended similarity with other proteins. In addition, we detected a high degree of sequence similarity with other SNF1-related proteinases in a small region (30-35 amino acids) flanking the C-terminus of the catalytic domain. This domain (designated the SNH domain) appears to define the subfamily of SNF1-related protein kinases and might represent a new type of regulatory domain of protein kinases.

Dyrk, a dual specificity protein kinase with unique structural features whose activity is dependent on tyrosine residues between subdomains VII and VIII.

The cDNA of a novel, ubiquitously expressed protein kinase (Dyrk) was cloned from a rat brain cDNA library. The deduced amino acid sequence (763 amino acids) contains a catalytic domain that is only distantly related to that of other mammalian protein kinases. Its closest relative is the protein kinase Mnb of Drosophila, which is presumably involved in postembryonic neurogenesis (85% identical amino acids within the catalytic domain). Outside the catalytic domain, the sequence comprises several striking structural features: a bipartite nuclear translocation signal, a tyrosine-rich hydrophilic motif flanking the nuclear localization signal, a PEST region, a repeat of 13 histidines, a repeat of 17 serine/threonine residues, and an alternatively spliced insertion of nine codons. A recombinant glutathione S-transferase-Dyrk fusion protein catalyzed autophosphorylation and histone phosphorylation on tyrosine and serine/threonine residues with an apparent Km of approximately 3.4 microM. Exchange of two tyrosine residues in the "activation loop" between subdomains VII and VIII for phenylalanine almost completely suppressed the activity and tyrosine autophosphorylation of Dyrk. Tyrosine autophosphorylation was also reduced by exchange of the tyrosine (Tyr-219) in a tyrosine phosphorylation consensus motif. The data suggest that Dyrk is a dual specificity protein kinase that is regulated by tyrosine phosphorylation in the activation loop and might be a component of a signaling pathway regulating nuclear functions.

[Antacids for postoperative prevention of stress ulcer in infants: a dose finding study]. / Antazida zur postoperativen Stressuljusprophylaxe bei Süglingen: Studie zur Dosisfindung.

UNLABELLED: In the prophylaxis of stress ulcers with antacids in young infants there are no recommendations of dosages that consider the physiologic maturation of gastric acid secretion. During the first six month of life the amount of gastric acid secretion in relation to body weight and body surface area increases exponentially. Therefore adult dosages of antacids cannot be transferred to infants. METHODS: In a cross over study 12 infants aged between 4 and 174 days, who had been undergoing a cardiosurgical intervention with the heart lung machine, were treated during 48 hours with 2 different antacid regimens over a period of 24 hours each, monitoring the gastric pH continuously. The used antacid consisted of an aluminium-magnesium complex (Al(OH)3, 90 mg/ml and Mg(OH)2, 60 mg/ml): Regimen A: 6 x 0.5 ml per kg body weight. Regimen B: 0.25 ml per kg body weight at a gastric pH less than 3, with the pH read every 30 minutes. RESULTS: Compared to 28 applications under regimen B, 72 single doses were given under regimen A, 58 of them at a gastric pH of higher than 3. Thus, the mean administered dose was significant lower under regimen B (2.2 ml) than under regimen A (12.0 ml). Consequently, the mean level of gastric pH was higher under regimen A (median: 5.96 +/- 1.31 versus 4.94 +/- 1.16). pH-values lower than 3 were more often measured under regimen B, whereas the phases at this pH-level were longer under regimen A. CONCLUSION: The usual body weight related dosage of antacids seems to be to high for early infancy. In the face of the discrepancy of the administered antacid quantity comparing regimen A with regimen B, it seems to be reasonable for the studied age group to reduce the single antacid dose to 0.25 ml/kg body weight while adhering to a high application frequency of 6 times a day.

Molecular cloning of a protein serine/threonine phosphatase containing a putative regulatory tetratricopeptide repeat domain.

Two novel protein serine/threonine phosphatases were cloned from a rat fat cell library with probes generated by a polymerase chain reaction-based cloning approach. One of these cDNAs encoded a protein presumably representing the rat homologue of PPV from Drosophila (75% identity of amino acids). The other novel cDNA encoded a protein phosphatase of 499 amino acids and was designated PPT. Its catalytic domain contains motifs typical for protein phosphatases but is only distantly related with PP1, PP2A, and PP2B (38-42% identical amino acids). When expressed in Escherichia coli, the catalytic domain of PPT exhibited protein phosphatase activity (dephosphorylation of phosphorylase a) that was inhibitable by okadaic acid. As a unique feature among other members of this gene family, PPT has an amino-terminal extension of 200 amino acids harboring three tandemly arranged tetratricopeptide repeat (TPR) motifs. This domain has previously been found in other proteins involved in the regulation of RNA synthesis or mitosis. mRNA of PPT was predominantly found in brain and, in lower levels, in testis, but was nearly undetectable in spleen, lung, skeletal muscle, kidney, and liver. It is suggested that the TPR domain of PPT may be involved in the regulation of the function of this novel protein phosphatase.