Neonates hypothyroidism

Rodriguez-Pena A, Ibarrola N, Iniguez MA, Munoz A, Bernal J 1993 Neonatal hypothyroidism affects the timely expression of myelin-associated glycoprotein in the rat brain. J Clin Invest 91 812-818... 

Developmentally, thyroid hormones interact with sex hormones such that hypothyroidism prolongs the critical period for testosterone-induced defeminization (see below) [3] in contrast, the hyperthyroid state prematurely terminates the sensitivity to testosterone [3]. Undoubtedly, an important link in these and other effects is synapse formation. Hypothyroidism increases synaptic density, at least transiently [3]. Interesting parallels with synapse formation are reported for learning behavior in rats neonatal hypothyroidism impairs learning ability, whereas hyperthyroidism accelerates learning initially, followed by a decline later in life [3]. 

W2. Werder, E. A., and Yaffe, S. J., Glucuronyltransferase activity in experimental neonatal hypothyroidism. Biol. Neonatorum 6, 8-15 (1964). 

Kallen and Robert (2000) found no adverse effects on congenital malformations, childhood cancer, infant mortality, low Apgar score, neonatal jaundice, or neonatal hypothyroidism among infants and children who lived in areas where drinking water was disinfected with chlorine dioxide, compared to controls living in... 

Severe transient postnatal hypothyroidism has been reported in infants whose mothers have received high doses of iodine during pregnancy or multiple local applications of povidone-iodine during pregnancy and for delivery (SED-14, 472). Transient neonatal hypothyroidism during breastfeeding after postnatal maternal topical iodine treatment has also been reported (68). 

Casteels K, Punt S, Bramswig J. Transient neonatal hypothyroidism during breastfeeding after post-natal maternal topical iodine treatment. Eur J Pediatr 2000 159(9) 716-717. 

Smerdely P, Lim A, Boyages SC, Waite K, Wu D, Roberts V, Leslie G, Arnold J, John E, Eastman CJ. Topical iodine-containing antiseptics and neonatal hypothyroidism in very-low-birthweight infants. Lancet 1989 2(8664) 661 1. 

Neonatal hypothyroidism has been reported after maternal use of antithyroid drugs (106,107). Transient neonatal hyperthyroidism in a female child born to a mother who had been treated with potassium iodide and carbimazole during pregnancy was followed by sexual precocity (108). 

Refetoff S, Ochi Y, Selenkow HA, Rosenfield RL. Neonatal hypothyroidism and goiter in one infant of each of two sets of twins due to maternal therapy with antithyroid drugs. J Pediatr 1974 85(2) 240-4. 

Because the irreversible mental retardation caused by neonatal hypothyroidism can be prevented by early treatment with thyroid hormone, the importance of early diagnosis of this disease has been emphasized. The difficulty of its early diagnosis by clinical features alone and its relatively high incidence have prompted the organization of various mass screening programs that include measuring thyroxine (T4) (D5) or TSH (13, Mil) by radioimmunoassay. 

Table 10 gives a list of enzyme immunoassays of substances related to neonatal hypothyroid screening. The methods for measuring substances in dried blood can be used for mass screening and those for tests on serum can be used for babies who are recalled. 

In 1976, we developed a double-antibody enzyme immunoassay of TSH using alkaline phosphatase, but this method was not very sensitive (M8). As shown in Table 10, several other methods were later reported (A3, 12, K2, K3, M7) and two methods have been used to measure TSH in dried blood samples in screening for neonatal hypothyroidism in Japan. 

One is a competitive double-antibody solid-phase method using perox-idase/TSH conjugates, which was reported by Kato et al. (K3). Their pilot study on mass screening for neonatal hypothyroidism has been successful. 

Enzyme Immunoassay for Substances Related to Neonatal Hypothyroid Screening... 

Free Thyroxine. Measurement of free T4 radioimmunoassay in dried blood samples has been found to be useful to avoid false-positive results for low TBG in neonatal hypothyroid screening. Enzyme immunoassay of free T4 in serum was developed by Weetall et al. (W7) and subsequently by us (16). 

Preliminary report on a mass screening program for neonatal hypothyroidism. J. Pediatr. 86, 670-674 (1975). 

Mil. Miyai, K., Nishi, K., Kawashima, M., Oura, T., and Tsuruhara, T., An improved assay of thyrotropin in dried blood samples on filter paper as a screening test for neonatal hypothyroidism. Clin. Chim. Acta 73, 241-249 (1976). 

Congenital goiter and neonatal hypothyroidism may occur if thiouracil drugs are administered during pregnancy (12). 

Leger FA, Denavit MF, Maria B, Savoie JC. Hypothyroidie neo-natale induite par I iode apres amniofoetographie. [Neonatal hypothyroidism induced by iodine after amniofetography.] Nouv Presse Med 1977 6(7) 563. ... 

Oide S, Yamaguchi H, Niizu N, Takahashi S, Takashima K. [Transient neonatal hypothyroidism probably due to contrast media used in fetal radiography.] Horumon To Rinsho 1983 31(Suppl) 76-9. 

Congenital hypothyroid disorders occur with a frequency of one in every 4000 live births (pp. 144—145). If diagnosed at an early age. replacement thyroid hormone can be given and normal development can occur. Delays in treatment result in cretinism (see p. 144). Elevated T.SH, measured in blood spots, is diagnostic of disorders of the thyroid itself, i.e. primary neonatal hypothyroidism. The TSH screening test does not pick up pituitary dysfunction in the newborn. 

Neonate Neonatal goiter Neonatal hypothyroidism Endemic mental retardation Increased susceptibility of the thyroid gland to nuclear radiation... 

When compared with age-matched healthy neonates, hypothyroid neonates had lower NAA/Cr ratios in their PWM and thalamus before treatment p < 0.05) (Figure 65.2a, c). Interestingly, both groups did not differ significantly with regard to FWM NAA/Cr ratios (Table 65.4). After a thyroxine treatment for 8 weeks, NAA/Cr ratios in PWM and the thalamus were increased significantly... 

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