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BJR Case Rep ; 6(4): 20200038, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33299590


An epidermal/(epi)dermoid cyst of the thyroid is a rare cause of an intrathyroidal mass. At radiological evaluation, it may initially be misinterpreted as a thyroid adenoma or carcinoma. We present a case report of a 15-year-old boy, who was evaluated because of a neck mass which caused globus pharyngeus and pain at swallowing. Ultrasound examination revealed a hypoechoic nodule-like structure in the left thyroid lobe. Aspiration of the nodule yielded white fluid. Cytological evaluation confirmed the diagnosis of an epidermal inclusion cyst of the thyroid.

Ned Tijdschr Geneeskd ; 1642020 05 20.
Artigo em Holandês | MEDLINE | ID: mdl-32749791


In this case series, we describe four children and adolescents with tall stature or growth acceleration to illustrate the diagnostic evaluation of tall stature according to the new Paediatric Association of the Netherlands (NVK) Guideline on growth disorders. A 14-year-old girl with tall stature and a relatively late onset of puberty was diagnosed with idiopathic familial tall stature, and the patient decided not to opt for epiphysiodesis. A 14-year-old boy with prepubertal growth acceleration and a history of behavioural problems was diagnosed with Klinefelter syndrome. A 7-year-old boy with tall stature, arachnodactyly, pectus excavatum and lumbar scoliosis was diagnosed with Marfan syndrome. Finally, a 16-year-old girl with isolated progressive tall stature was diagnosed with growth hormone excess caused by a pituitary somatotroph adenoma. The most clinically relevant conditions associated with tall stature are Klinefelter and Marfan syndrome, and secondary growth disorders such as precocious puberty and growth hormone excess.

J Clin Endocrinol Metab ; 105(7)2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32282051


CONTEXT: C-type natriuretic peptide (CNP) is critically involved in endochondral bone growth. Variants in the genes encoding CNP or its cyclic guanosine monophosphate (cGMP)-forming receptor (natriuretic peptide receptor-B [NPR-B], gene NPR2) cause monogenic growth disorders. Here we describe a novel gain-of-function variant of NPR-B associated with tall stature and macrodactyly of the great toes (epiphyseal chondrodysplasia, Miura type). DESIGN: History and clinical characteristics of 3 family members were collected. NPR2 was selected for sequencing. Skin fibroblasts and transfected HEK-293 cells were used to compare mutant versus wild-type NPR-B activities. Homology modeling was applied to understand the molecular consequences of the variant. RESULTS: Mother's height was +2.77 standard deviation scores (SDS). The heights of her 2 daughters were +1.96 SDS at 7 years and +1.30 SDS at 4 years of age. Skeletal surveys showed macrodactyly of the great toes and pseudo-epiphyses of the mid- and proximal phalanges. Sequencing identified a novel heterozygous variant c.1444_1449delATGCTG in exon 8 of NPR2, predicted to result in deletion of 2 amino acids Met482-Leu483 within the submembrane region of NPR-B. In proband's skin fibroblasts, basal cGMP levels and CNP-stimulated cGMP production were markedly increased compared with controls. Consistently, assays with transfected HEK-293 cells showed markedly augmented baseline and ligand-dependent activity of mutant NPR-B. CONCLUSIONS: We report the second activating variant within the intracellular submembrane region of NPR-B resulting in tall stature and macrodactyly. Our functional and modeling studies suggest that this domain plays a critical role in the baseline conformation and ligand-dependent structural rearrangement of NPR-B required for cGMP production.

Horm Res Paediatr ; 91(5): 293-310, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31302655


Tall stature and/or accelerated growth (TS/AG) in a child can be the result of a primary or secondary growth disorder, but more frequently no cause can be found (idiopathic TS). The conditions with the most important therapeutic implications are Klinefelter syndrome, Marfan syndrome and secondary growth disorders such as precocious puberty, hyperthyroidism and growth hormone excess. We propose a diagnostic flow chart offering a systematic approach to evaluate children referred for TS/AG to the general paediatrician. Based on the incidence, prevalence and clinical features of medical conditions associated with TS/AG, we identified relevant clues for primary and secondary growth disorders that may be obtained from the medical history, physical evaluation, growth analysis and additional laboratory and genetic testing. In addition to obtaining a diagnosis, a further goal is to predict adult height based on growth pattern, pubertal development and skeletal maturation. We speculate that an improved diagnostic approach in addition to expanding use of genetic testing may increase the diagnostic yield and lower the age at diagnosis of children with a pathologic cause of TS/AG.

Acromegalia/diagnóstico , Transtornos do Crescimento/diagnóstico , Puberdade Precoce/diagnóstico , Acromegalia/etiologia , Criança , Pré-Escolar , Feminino , Transtornos do Crescimento/etiologia , Humanos , Hipertireoidismo/complicações , Hipertireoidismo/diagnóstico , Síndrome de Klinefelter/complicações , Síndrome de Klinefelter/diagnóstico , Masculino , Síndrome de Marfan/complicações , Síndrome de Marfan/diagnóstico , Puberdade Precoce/etiologia
J Am Chem Soc ; 128(20): 6683-9, 2006 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-16704270


A new reaction sequence for the chemical functionalization of single-wall carbon nanotubes (SWNTs) consisting of the nucleophilic addition of t-BuLi to the sidewalls of the tubes and the subsequent reoxidation of the intermediates t-Bu(n)SWNT(n-) leading to t-Bu(n)SWNT was developed. During the formation of the t-Bu(n)SWNT(n-), a homogeneous dispersion in benzene was formed due to the electrostatic repulsion of the negatively charged intermediates causing debundling. The entire reaction sequence can be repeated, and the degree of functionalization of the products (t-Bu(n))(m)SWNT (m = 1-3) increases with increasing m. Degrees of functionalization expressed as the carbon-to-addend ratio of up to 31 were reached. The reaction was studied in detail by photoelectron spectroscopy, Raman spectroscopy, and scanning tunneling microscopy (STM). The C 1s core level spectra reveal that the nucleophilic attack of the t-BuLi leads to negatively charged SWNTs. Upon oxidation, this negative charge is removed. The valence band spectra of the functionalized samples exhibit a significant reduction in the pi-derived density of states. In STM, the covalently bonded t-butyl groups attached to the sidewalls have been visualized. Raman spectroscopy reveals that addition of the nucleophile to metallic tubes is preferred over the addition to semiconducting tubes.