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Background/purpose: Thyroid disorders are common in children with Down syndrome (DS), however, such data have rarely been reported in Taiwanese children. This study presents our experience with the management of these children. Methods: Between 2006 and 2016, 51 children (31 boys and 20 girls) with DS were enrolled. Thyroid function was evaluated and natural course of thyroid status were analyzed. Results: Of 51 patients with DS, 2 had congenital hypothyroidism due to dyshormonogenesis. Of the remaining 49 patients, 30 (61%) had euthyroidism (EuT), and 19 (39%) had subclinical hypothyroidism (SH). Eighteen (37%) had detectable thyroid antibodies. It occurred at any age and the incidence was not affected by sex. The mean follow-up duration for 39 DS children was 3.8 ± 2.4 years. Of the 26 children who had EuT at enrollment and were followed up, 22 remained EuT, 2 developed SH, 1 developed overt hypothyroidism, and 1 developed overt hyperthyroidism. Of the 13 patients with SH who were followed up, 1 was treated for high thyroid-stimulating hormone levels, 8 became EuT, and 4 maintained SH status. Children with DS and persistent SH had significantly higher maximum thyroid-stimulating hormone levels during follow-up than did those with transient SH. Fluctuation in thyroid status during follow-up was not uncommon in children with DS. Conclusion: The prevalence of thyroid disorders is higher in Taiwanese children with DS than in the general population. Because symptoms of hypothyroidism overlap those inherent to DS, regular follow-up of thyroid function in children with DS is indicated. Keywords: Anti-thyroperoxidase antibody, Anti-thyroglobulin antibody, Congenital hypothyroidism, Down syndrome, Subclinical hypothyroidism

Background/Aims: Endothelin-1 is implicated in the pathogenesis of hypertension, but the underlying mechanisms remained elusive. Our previous study found that inhibition of mitochondrial fission of smooth muscle cells suppressed phenylephrine- and high K+-induced artery constriction. Here, we studied the effects of mitochondrial fission inhibitors on endothelin-1-induced vasoconstriction. Methods: The tension of rat mesenteric arteries and thoracic aorta was measured by using a multi-wire myograph system. Mitochondrial morphology of aortic smooth muscle cells was observed by using transmission electron microscopy. Results: Dynamin-related protein-1 selective inhibitor mdivi-1 relaxed endothelin-1-induced constriction, and mdivi-1 pre-treatment prevented endothelin-1-induced constriction of rat mesenteric arteries with intact and denuded endothelium. Mdivi-1 had a similar inhibitory effect on rat thoracic aorta. Another mitochondrial fission inhibitor dynasore showed similar effects as mdivi-1 in rat mesenteric arteries. Mdivi-1 inhibited endothelin-1-induced increase of mitochondrial fission in smooth muscle cells of rat aorta. Rho-associated protein kinase inhibitor Y-27632 which relaxed endothelin-1-induced vasoconstriction inhibited endothelin-1-induced mitochondrial fission in smooth muscle cells of rat aorta. Conclusion: Endothelin-1 increases mitochondrial fission in vascular smooth muscle cells, and mitochondrial fission inhibitors suppress endothelin-1-induced vasoconstriction.

Abstract Background Kawasaki disease (KD) is an acute systemic vasculitis that occurs in children and may lead to cardiovascular morbidity and mortality. Progressive coronary dilatation for at least 2 months is associated with worse late coronary outcomes in patients with KD having medium or giant aneurysms. However, the risk factors and occurrence of progressive coronary dilatation in patients with KD but without medium or giant aneurysms have been insufficiently explored. Methods We retrospectively enrolled 169 patients with KD from a tertiary medical center in Taiwan during 2009–2013. Medical records of all patients were reviewed. Echocardiography was performed during the acute KD phase and at 3–4 weeks, 6–8 weeks, 6 months, and 12 months after KD onset. Progressive coronary dilatation was defined as the progressive enlargement of coronary arteries on three consecutive echocardiograms. Logistic regression analysis was conducted to evaluate the potential risk factors for coronary aneurysms and progressive coronary dilatation. Results Of a total of 169 patients with KD, 31 (18.3%) had maximal coronary Z-scores of ≥ + 2.5 during the acute KD phase, 16 (9.5%; male/female: 9/7) had coronary aneurysms at 1 month after KD onset, and 5 (3.0%) satisfied the definition of progressive coronary dilatation. Multivariate logistic regression analysis revealed that an initial maximal coronary Z-score of ≥ + 2.5 [odds ratio (OR): 5.24, 95% confidence interval (CI): 1.31–21.3, P = 0.020] and hypoalbuminemia (OR: 4.83, 95% CI: 1.11–20.9, P = 0.035) were independent risk factors for coronary aneurysms and were significantly associated with progressive coronary dilatation. However, the association between intravenous immunoglobulin unresponsiveness and the development of coronary aneurysms at 1 month after KD onset didn’t reach the level of significance (P = 0.058). Conclusions In the present study, 3% (5/169) of patients with KD had progressive coronary dilatation, which was associated with persistent coronary aneurysms at 1 year after KD onset. Initial coronary dilatation and hypoalbuminemia were independently associated with the occurrence of progressive coronary dilatation. Therefore, such patients may require intensive cardiac monitoring and adjuvant therapies apart from immunoglobulin therapies.

Background/Aims: Copper is an essential trace element for normal cellular function and contributes to critical physiological or pathological processes. The aim of the study was to investigate the effects of copper on vascular tone of rat mesenteric artery and compare the effects of copper on noradrenaline (NA) and high K+ induced vasoconstriction. Methods: The rat mesenteric arteries were isolated and the vessel tone was measured by using multi wire myograph system in vitro. Blood pressure of carotid artery in rabbits was measured by using physiological data acquisition and analysis system in vivo. Results: Copper dose-dependently blunted NA-induced vasoconstriction of rat mesenteric artery. Copper-induced vasorelaxation was inhibited when the vessels were pretreated with NG-nitro-L-arginine methyl ester (L-NAME). Copper did not blunt high K+-induced vasoconstriction. Copper preincubation inhibited NA-evoked vasoconstriction and the inhibition was not affected by the presence of L-NAME. Copper preincubation showed no effect on high K+-evoked vasoconstriction. Copper chelator diethyldithiocarbamate trihydrate (DTC) antagonized the vasoactivity induced by copper in rat mesenteric artery. In vivo experiments showed that copper injection (iv) significantly decreased blood pressure of rabbits and NA or DTC injection (iv) did not rescue the copper-induced hypotension and animal death. Conclusion: Copper blunted NA but not high K+-induced vasoconstriction of rat mesenteric artery. The acute effect of copper on NA-induced vasoconstriction was depended on nitric oxide (NO), but the effect of copper pretreatment on NA-induced vasoconstriction was independed on NO, suggesting that copper affected NA-induced vasoconstriction by two distinct mechanisms.

Management is an effective tool for increasing the productivity of Mongolian pine (Pinus sylvestris var. mongolica). This species has been widely planted in China, especially in sandy lands. However, optimization of management practices had not been fully explored. We established a system dynamic model to evaluate the effects of thinning and of manipulation of water supply on the productivity and population density of a Mongolian pine forest (17 scenarios in total). Different levels of thinning increased the mean biomass of Mongolian pine over no-management to a range from 202 to 256 t·ha-1. Increasing water supply decreased the mean biomass of Mongolian pine to a range from 176 to 199 t·ha-1. These results indicated that thinning at different levels may lead to an increase in biomass accumulation, while manipulating water supply may decrease biomass. Further, thinning appeared more effective than increasing water supply in efforts at maintaining high productivity of Mongolian pine forests. Moreover, the highest biomass occurred in a scenario with a thinning intensity of 30% in over-mature trees, indicating that this thinning intensity was the most effective choice for to the maintenance of the highest biomass in Mongolian pine forests. This study informs about the interactions between Mongolian pine and forest management, and provides guidelines for the practice of management of this forest type.