Cardiotoxicity of environmental contaminant tributyltin involves myocyte oxidative stress and abnormal Ca2+ handling.

Tributyltin (TBT) is an organotin environmental pollutant widely used as an agricultural and wood biocide and in antifouling paints. Countries began restricting TBT use in the 2000s, but their use continues in some agroindustrial processes. We studied the acute effect of TBT on cardiac function by analyzing myocardial contractility and Ca2+ handling. Cardiac contractility was evaluated in isolated papillary muscle and whole heart upon TBT exposure. Isolated ventricular myocytes were used to measure calcium (Ca2+) transients, sarcoplasmic reticulum (SR) Ca2+ content and SR Ca2+ leak (as Ca2+ sparks). Reactive oxygen species (ROS), as superoxide anion (O2•-) was detected at intracellular and mitochondrial myocardium. TBT depressed cardiac contractility and relaxation in papillary muscle and intact whole heart. TBT increased cytosolic, mitochondrial ROS production and decreased mitochondrial membrane potential. In isolated cardiomyocytes TBT decreased both Ca2+ transients and SR Ca2+ content and increased diastolic SR Ca2+ leak. Decay of twitch and caffeine-induced Ca2+ transients were slowed by the presence of TBT. Dantrolene prevented and Tiron limited the reduction in SR Ca2+ content and transients. The environmental contaminant TBT causes cardiotoxicity within minutes, and may be considered hazardous to the mammalian heart. TBT acutely induced a negative inotropic effect in isolated papillary muscle and whole heart, increased arrhythmogenic SR Ca2+ leak leading to reduced SR Ca2+ content and reduced Ca2+ transients. TBT-induced myocardial ROS production, may destabilize the SR Ca2+ release channel RyR2 and reduce SR Ca2+ pump activity as key factors in the TBT-induced negative inotropic and lusitropic effects.

Hyperinsulinemic hypoglycemia in Beckwith-Wiedemann syndrome due to defects in the function of pancreatic beta-cell adenosine triphosphate-sensitive potassium channels.

BACKGROUND: Beckwith-Wiedemann syndrome (BWS) is a congenital overgrowth syndrome that is clinically and genetically heterogeneous. Hyperinsulinemic hypoglycemia occurs in about 50% of children with BWS and, in the majority of infants, it resolves spontaneously. However, in a small group of patients the hypoglycemia can be persistent and may require pancreatectomy. The mechanism of persistent hyperinsulinemic hypoglycemia in this group of patients is unclear. PATIENTS AND METHODS: Using patch-clamp techniques on pancreatic tissue obtained at the time of surgery, we investigated the electrophysiological properties of ATP-sensitive K(+) (K(ATP)) channels in pancreatic beta-cells in a patient with BWS and severe medically-unresponsive hyperinsulinemic hypoglycemia. RESULTS: Persistent hyperinsulinism was found to be caused by abnormalities in K(ATP) channels of the pancreatic beta-cell. Immunofluorescence studies using a SUR1 antibody revealed perinuclear pattern of staining in the BWS cells, suggesting a trafficking defect of the SUR1 protein. No mutations were found in the genes ABCC8 and KCNJ11 encoding for the two subunits, SUR1 and KIR6.2, respectively, of the K(ATP) channel. Genetic analysis of this patients BWS showed evidence of mosaic paternal isodisomy. CONCLUSIONS: In this novel case of BWS with mosaic paternal uniparental disomy for 11p15, persistent hyperinsulinism was due to abnormalities in K(ATP) channels of the pancreatic beta-cell. The mechanism/s by which mosaic paternal uniparental disomy for 11p15 causes a trafficking defect in the SUR1 protein of the K(ATP) channel remains to be elucidated.

Cushing's disease in childhood as the first manifestation of multiple endocrine neoplasia syndrome type 1.

OBJECTIVE: To describe three cases of Cushing's disease in children with multiple endocrine neoplasia type 1 (MEN1), as clinical manifestations of MEN1 are very rare in childhood. DESIGN AND METHODS: A retrospective review of three cases of Cushing's disease diagnosed between 1997 and 1999. Genetic screening for MEN1 gene mutation was performed in each patient. RESULTS: An ACTH-secreting microadenoma was diagnosed in three children, aged 11-13 years, presenting with growth retardation and weight gain over a period of 3-4 years. All patients had successful transsphenoidal adenomectomies. Primary hyperparathyroidism was subsequently diagnosed in two of the patients, and in the monozygotic twin of one of the patients. A new mutation in the MEN1 gene (Tyr351His) was identified in two of the patients and the affected members of their families. In the third patient a de novo MEN1 gene mutation (Leu444Pro) was found. CONCLUSIONS: MEN1 has to be considered in all children with tumours of the pituitary gland, and in those presenting with primary hyperparathyroidism. The children and their families should be advised to seek genetic counselling. We suggest that careful growth records be kept for children at risk of developing inherited MEN1 and, in the event of a decelerating growth rate, further diagnostic evaluation be undertaken with regards to ACTH-secreting pituitary tumours.

Association of a putative regulatory polymorphism in the PD-1 gene with susceptibility to type 1 diabetes.

The immunoreceptor programmed cell death-1 (PD-1) is reported to play an important role in the regulation of peripheral tolerance in rodents, and it was recently shown that a polymorphism in a regulatory site of the PD-1 gene is associated with susceptibility to the autoimmune disease systemic lupus erythematosus (SLE) in humans. We investigated the existence of single-nucleotide polymorphisms (SNPs) in the PD-1 gene in patients with type 1 diabetes in comparison with healthy control subjects, by analyzing 94 children and adolescents with type 1 diabetes diagnosed before their eighteenth birthday (male : female = 52 : 42) and 155 control subjects. Polymorphisms in the complete PD-1 gene (minus the large intron 1) were detected by sequencing. In total, we identified 14 SNPs, of which six have been previously described, including an intronic 7146G/A SNP. We found this polymorphism to be associated with the development of type 1 diabetes [found in 12.2% of diabetic individuals vs 6.8% in controls; odds ratio (OR) = 1.92]. The associated allele is previously shown to alter a transcription factor-binding site (RUNX1/AML1), and the results of this study suggest that this allele could act as an additional susceptibility allele to type 1 diabetes.

Late relapse of adrenocortical carcinoma in Beckwith-Wiedemann syndrome. Clinical, endocrinological and genetic aspects.

UNLABELLED: We report on a girl with an unusual Beckwith-Wiedemann syndrome (BWS) and hemihypertrophy, who developed an adrenocortical carcinoma with atypical clinical behaviour. At 4 y of age the girls was admitted to hospital with cushingoid features, virilization, increased excretion of steroids and low serum ACTH. A right-sided adrenocortical carcinoma was removed. At age 12.5 y the cushingoid features reappeared together with a tumour in the left thigh. A CT scan of the thorax and abdomen revealed pulmonary metastasis only. Corticosteroid excretion was increased and serum ACTH level suppressed. The femoral and the pulmonary metastases were removed and histology showed adrenocortical carcinoma. Excretion of corticosteroids subsequently normalized. Meningeal and pulmonary metastases with similar histologies appeared one year later with normal hormone values. Twenty-two months after the recurrence the girl died of an intracranial metastasis. Southern blot analysis of the LITI transcript in the KvLQT1 gene in the BWS region on chromosome 11p15 revealed hypomethylation of the maternal allele. CONCLUSION: Adrenocortical carcinoma in childhood may recur years after onset and at rare sites and hormonal levels may be an insufficient indicator of small metastases.

A prospective study of thyroid function, morphology and autoimmunity in young patients with type 1 diabetes.

OBJECTIVE: Thyroid autoantibodies (TA) and thyroid ultrasonography are widely used in the diagnosis of autoimmune thyroid disease (AITD). However, we know little of the significance of having ultrasonographic abnormalities (USabn) without having any other signs of AITD. In a previous population-based study of 105 young patients with type 1 diabetes (T1DM) we found a high prevalence (42%) of USabn. In the present study we evaluate the development of both USabn and TA in a 3-Year follow-up of this cohort. DESIGN: Of the 105 previously investigated children and adolescents with T1DM (aged 5-21 Years), 101 were re-examined. Serum concentrations of tri-iodothyronine (T(3)), thyroxine (T(4)), TSH, thyroid peroxidase antibodies (TPOab) and thyroglobulin antibodies (Tgab), as well as thyroid size and morphology were determined in all patients. RESULTS: During the 3 Years follow-up period, the prevalence of thyroid dysfunction increased from 5 to 8%, the prevalence of TPOab was unchanged at 13%, while the prevalence of Tgab decreased from 14 to 7%. The prevalence of USabn increased from 42 to 49%. Most patients presented USabn at both examinations. Patients with USabn had a higher prevalence of TA than those without USabn (P=0.038) and higher serum levels of TSH (P=0.027). All patients with thyroid dysfunction presented with USabn. However, many patients with USabn had no other signs of AITD. CONCLUSIONS: A high prevalence of thyroid dysfunction, TA and thyroid USabn were found in young patients with T1DM. Thyroid USabn was a sensitive but non-specific marker of AITD and is therefore unsuitable for screening purposes. Instead, we recommend regular screening using serum TSH in the follow-up of young diabetic patients.

Pancreatic beta-cell stimulation tests in transient and persistent congenital hyperinsulinism.

UNLABELLED: In congenital hyperinsulinism (HI). the in vivo pancreatic beta-cell function is poorly described. Among 14 neonates with severe hyperinsulinaemic hypoglycaemia, 2 patients had very prolonged or persistent hypoglycaemia and mutation in the sulphonylurea receptor SURI gene. Patient 1 had transient HI and was treated medically for 3.5 mo before clinical remission was seen. He had initially very high basal and stimulated C-peptide and insulin levels, followed by a state of normal preprandial values, but blunted beta-cell glucose sensitivity, before complete beta-cell normalization occurred. A single. paternal SURI mutation, G1382S, was found suggesting focal type HI. Patient 2 had persistent HI and underwent 3 pancreas resections up to the age of 2 y, 7 mo, followed by a state of mild diabetes. On biopsy, diffuse-type beta-cell hypertrophy was seen. The beta-cell response to glucose and glucagon stimulation was blunted before, as well as after, pancreas resections. Compound heterozygosity for the SUR1 mutations 3992-3c to g and N188S was found. CONCLUSION: Transient, possibly focal, HI with paternal SUR1 mutation was associated with a gradual, but complete normalization of the in vivo beta-cell function; in the diffuse type HI, a blunted beta-cell response to glucose and glucagon stimulation persisted. In vivo beta-cell stimulation tests may contribute to the characterization of the HI subtypes.

[Congenital hyperinsulinism]. / Kongenit hyperinsulinisme.

In the last five years, our knowledge about the heterogenous syndrome of congenital hyperinsulinism (HI) has expanded explosively. HI may be familiar or sporadic, mild or severe, transitory or persistent, and histologically focal or diffuse. At least 63 disease-causing mutations have been found in the genes for the beta cell's ATP-dependent potassium channel, whose elements are the sulphonylurea receptor, SUR1, and Kir6.2. Other mutations cause enhancement of the glucose-stimulated ATP production in the beta cell. The resulting non-functional, or closed, potassium channel causes hypersecretion of insulin. Genetic screening has succeeded in detecting mutations in less than 50% of HI-patients. Genotype-phenotype relations, diagnosis and treatment are reviewed.

High prevalence of coeliac disease in Danish children with type I diabetes mellitus.

UNLABELLED: The purpose of this population-based study was to determine the prevalence of coeliac disease (CD) in 106 Danish children (age 2-18 y) with type I diabetes mellitus compared with 106 age- and sex-matched healthy controls. Serum samples were analysed for immunoglobulin A (IgA) and IgG gliadin antibodies by enzyme-linked immunosorbent assay (ELISA), for IgA endomysium antibodies (EMA) by immunofluorescence and for IgA tissue transglutaminase antibodies (tTGA) by ELISA. None of the controls had EMA or tTGA. Two diabetics previously diagnosed with CD were antibody negative on a gluten-free diet. Ten diabetics had both EMA and tTGA. Intestinal biopsy was performed in nine of them. All biopsies showed a histological picture of partial or total villous atrophy confirming the diagnosis of CD. Diabetics with CD were significantly younger (p = 0.026). had an earlier onset of diabetes (p = 0.005), had a lower height standard deviation score (p = 0.019) and more often had thyroid antibodies (p = 0.040) compared with diabetics without CD. CONCLUSION: A high prevalence of CD of 10.4% (95% confidence interval 4.6-16.2%) was found in young Danish diabetics. Early onset of diabetes may predispose to CD. Routine serological screening for CD may be valuable in patients with type I diabetes mellitus.

Prevalence of thyroid peroxidase, thyroglobulin and thyrotropin receptor antibodies in a long-term follow-up of juvenile Graves disease.

OBJECTIVE: To relate the presence of thyroid peroxidase antibodies (TPO ab), thyroglobulin antibodies (Tg ab) and thyrotropin receptor antibodies (TSH-R ab) to the clinical course in a long-term follow-up of patients with juvenile Graves' disease (JGD). DESIGN: Patients with JGD were drawn from a Danish retrospective study and reexamined. RESULTS: A number of 105 patients were reexamined 4-21 years (median 10 years) after diagnosis. Three groups were formed: Gr.1: euthyroid patients with anti-thyroid drug (ATD) cessation more than 12 months before reexamination (n=41). Gr.2: patients still on ATD (n=24). Gr.3: subtotally thyroidectomized patients (n=40). Positive TPO ab titers were found in 75% of the patients. In 13% of the patients the titers were very high: >10,000 U/ml. Positive Tg ab were found in 51%. The prevalence of TPO ab and Tg ab was the lowest in group 3. Stimulating TSH-R ab titers were found in 13%. No patients had blocking TSH-R ab. The prevalence of TSH-R ab was 3% in the euthyroid patients, without surgery performed. 15% in the surgical patients, and 25% in the patients still on ATD. CONCLUSIONS: Many JGD patients were euthyroid at the long-term follow-up in spite of high TPO ab and Tg ab titers. Stimulating TSH-R ab were rare (13%). According to this presence of TPO ab, Tg ab or TSH-R ab does not predict the final outcome of JGD. Further studies are needed.

[Zellweger syndrome--a peroxisomal disease]. / Zellwegers syndrom--en peroxisomal sygdom.

Zellweger syndrome is a fatal recessively inherited disease with disturbed function of many organs. The disease is caused by a defect of peroxisomes, subcellular organelles, which are absent in these patients. Several genes are necessary for the formation and function of the peroxisomes. The clinical picture of Zellweger syndrome can be caused by defects in a number of genes. On the other hand, clinically different diseases such as neonatal adrenoleucodystrophy and infantile Refsum disease have been shown to be allelic to Zellweger syndrome. We describe a typical Zellweger patient belonging to complementation group 1, which is by far the largest group containing more than half of the Zellweger patients.

[Granulosa cell tumors in children]. / Granulosacelletumorer hos børn.

Juvenile granulosa cell tumours (JGCT) are rare. They may develop in ovarian or testicular tissue. In childhood a special histological type called juvenile granulosa cell tumour (JGCT) is seen. Four cases are described: Congenital JGCT in a child with sex chromosomal abnormity (45 XO/46 XdicYq) and tumour arising from immature testicular tissue, JGCT in the testis of a four month old boy, JGCT associated with a hypothalmic hamartoma in a 18 month-old girl, and JGCT in an eight year-old girl. In all cases the tumours were benign.

Norditropin SimpleXx: a liquid human growth hormone formulation, a pen system and an auto-insertion device.

Patient compliance is of vital importance for the outcome of any medical therapy. Compliance is especially a problem in long-term treatment of non-life threatening diseases, such as growth retardation in children. Until recently, all human growth hormone (hGH) products required a reconstitution process. Norditropin((R)) SimpleXx(TM) is a liquid formulation of the biosynthetic hGH product Norditropin((R)), and, together with an improved NovoPen((R)) 1.5, NordiPen(TM), and an auto-insertion device, PenMate(TM)/NordiPenMate(TM), it has been developed in order to ease the injection process for patients. A randomized, open, multicentre, crossover trial compared Norditropin((R)) SimpleXx(TM)/improved NovoPen((R)) 1.5 with freeze-dried Norditropin((R)) PenSet((R))/Nordiject((R)). A total of 67 children with GH deficiency, aged 5-18 years, were treated with either Norditropin((R)) SimpleXx(TM) for 6 weeks followed by Norditropin((R)) for 6 weeks or the opposite (sequences I and II, respectively). Acceptability/convenience and pain perception were evaluated by questionnaire after each period. The function and handling of the PenMate(TM) were evaluated in a Dutch trial by 27 GH-treated children with intrauterine growth retardation, aged 4-16 years, and their parents. All children were accustomed to using the Nordiject((R)) pen. The evaluation of the PenMate(TM) was based on a questionnaire. A similar trial was conducted in England, in which the NordiPen(TM) and the NordiPenMate(TM) were evaluated by 25 GH-treated children and their parents. Norditropin((R)) SimpleXx(TM) was found to be easier to inject by 64% of the children, and 98% of the children found the system easier to use overall. There was no difference in pain perception between the two administration systems, as judged by questionnaires and visual analogue scale score. Three out of four patients preferred to continue treatment with Norditropin((R)) SimpleXx(TM). The safety profiles of the two systems were similar. In the Dutch trial, the PenMate(TM) was found to be easy and safe to handle, even for very young children (aged 4-5 years). Of patients who took a long time to get used to the injections, 73% found that the new pen would help. A total of 88% of the children would prefer to use the PenMate(TM) in the future. Positive results of the handling tests were also reported in the British trial. The use of Norditropin((R)) SimpleXx(TM) and the auto-insertion device may improve patient compliance.

Thyroid function, morphology and autoimmunity in young patients with insulin-dependent diabetes mellitus.

OBJECTIVE: An association between insulin-dependent diabetes mellitus (IDDM) and autoimmune thyroid disease is well recognized. We have studied the prevalence of thyroid dysfunction, autoimmunity and morphological abnormalities by ultrasonography in young diabetics. SUBJECTS AND METHODS: Among young IDDM patients less than 18 years old and living in the county of Funen, Denmark, 105 of 116 eligible patients participated. They were compared with 105 healthy children matched for sex and age. Routine thyroid function parameters (thyroxine (T4), tri-iodothyronine (T3), T3 resin uptake and TSH) and thyroid autoantibodies (anti-thyroid peroxidase, TPOab, and thyroglobulin antibodies, Tgab) were measured. Thyroid size and morphology were determined by ultrasonography. RESULTS: Two of the diabetics had previously diagnosed hypothyroidism and three new cases of subclinical hypothyroidism were found. There were no significant differences in thyroid function variables or thyroid volume between diabetics and controls. Thyroid volume correlated significantly with age and weight in both groups. Among diabetics, 17 had thyroid autoantibodies (13 with TPOab, 14 with Tgab and 10 with both) compared with 2 children in the control group (P<0.001). Forty-four with IDDM as opposed to 11 of the controls (P<0.001) had morphological abnormalities at ultrasonography. Most of them had various degrees of hypoechogenicity thought to be a marker of thyroid autoimmunity. Among the 17 diabetics with autoantibodies, 10 had morphological abnormalities at ultrasonography. CONCLUSIONS: A high proportion of young IDDM patients without any clinical signs of thyroid disease have markers of thyroid autoimmunity. Many have thyroid autoantibodies, but even more have abnormalities by thyroid ultrasonography.

[TSH-receptor blocking antibodies in juvenile thyrotoxicosis]. / TSH-receptorblokerende antistoffer ved juvenil tyreotoksikose.

The case presented is a 12 year-old girl with hyperthyroidism due to juvenile Grave's disease, who during the course of treatment developed hypothyroidism due to TSH-receptor blocking antibodies, measured by bioassay. The bioassay used was performed on CHO-R cells measuring c-AMP. The role of radioreceptor assays and bioassays in measuring TSH receptor antibodies in hyper- and hypothyroid Graves' disease in discussed.

HLA class II associations in juvenile Graves' disease: indication of a strong protective role of the DRB1*0701,DQA1*0201 haplotype.

Previous studies have shown that HLA-DRB1*0301 and DQA1*0501 are associated with susceptibility to Graves' disease. Ninety Danish patients with early onset of Graves' disease and 102-192 controls were analyzed for HLA-DR and -DQ to investigate if the same associations exist in the juvenile form of Graves' disease. Both DRB1*0301 and DQA1*0501 were highly significantly increased in the patients with relative risks of 8.0 and 4.6, which are higher than those seen in adults. Stratification showed that DRB1*0301 is more strongly associated than DQA1*0501. Surprisingly, the DRB1*0701,DQA1*0201 haplotype was completely absent from this group of patients, indicating a strong protective role of this haplotype in juvenile Graves' disease.

[Isolated congenital growth hormone deficiency. Severe hypoglycemia and neonatal giant cell hepatitis]. / Isoleret kongenit vaeksthormonmangel. Svoer hypoglykoemi og neonatal koempecellehepatitis.

A case of congenital isolated growth hormone deficiency with neonatal giant cell hepatitis is described. Hypoplasia of the pituitary gland was detected by a MR-scan. Values of IGF-I, IGF-II, and IGF-BP-3 were low. Birth length and weight were normal; hypoglycaemia, jaundice, and failure to thrive were the most pronounced symptoms and present from the first day. Substitution therapy with growth hormone induced a remission of all symptoms. Growth was normal at follow-up at the age of two and a half years.

Intensive chemotherapy in childhood myelodysplastic syndrome. A comparison with results in acute myeloid leukemia.

Myelodysplastic syndrome (MDS) in children is often considered as a variant of acute myeloid leukemia (AML) and frequently treated as such. However, there are very few reported data on the outcome following AML treatment. We analyzed 20 consecutive cases of de novo MDS treated in Denmark according to the NOPHO AML protocols. The results were compared with those obtained in 31 children with de novo AML treated with the same protocols, and with the outcome in 10 children with MDS who received allogeneic bone marrow transplantation (BMT) without prior AML therapy. Distinction between MDS and AML was made morphologically according to the FAB criteria. All children were followed for at least 37 months. The proportion of complete remission in MDS and AML was 35 percent vs 74 percent. (P = 0.005), resistant disease 25 percent vs 10 percent (P = 0.14), death in cytopenia 40 percent vs 16 percent (P= 0.06), and 3-year survival 15 percent vs 35 percent. (P = 0.11), respectively. Duration of treatment-related cytopenia was similar in MDS and AML, except for a longer period of leukopenia in MDS following the second course of induction. Seven of 10 MDS children receiving BMT without prior chemotherapy are long-term survivors. Our data suggest that conventional AML regimens are associated with a low rate of complete remission, a high risk of death in cytopenia, and a limited curative potential in childhood MDS. Allogeneic BMT was in contrast associated with a high survival rate. BMT may, at least in some patients, be performed successfully without prior induction chemotherapy. The different response to therapy in MDS and AML may reflect fundamental biological differences between the two conditions.