The Thyroid Gland

Bürgi, H

doi:10.1007/978-3-642-70509-0_6

Cited by 4 publications

(1 citation statement)

References 1,659 publications

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“…Mild thyroid dysfunction was observed in some patients (4,8). Two children had the euthyroid sick syndrome, a hypothyroid-like state with diminished FT3 levels, with or without low FT4 (25) and TSH mostly normal (26). This syndrome, typically found in chronically ill patients, has scarce clinical relevance, but may be an additional indicator of metabolic breakdown.…”

Section: Discussionmentioning

confidence: 99%

Growth impairment, IGF I hyposecretion and thyroid dysfunction in children with perinatal HIV‐1 infection

et al. 1994

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We evaluated the growth pattern, bone age, insulin-like growth factor I (IGF I) secretion and thyroid function in 24 perinatally infected children: 9 asymptomatic or paucisymptomatic (group 1) and 15 with a more advanced disease state and treated with zidovudine (group 2). Statural and ponderal growth were compared with those of 37 at-risk children who seroreverted. During the two-year follow-up, 22% of children in group 1 had impaired growth, 33% bone age delay, 45% reduced IGF I levels but none had thyroid dysfunction. In group 2, 53% had growth failure, 53% bone age delay, 86% reduced IGF I levels and 40% thyroid dysfunction. Among seroreverters, none showed growth impairment; statistically significant differences were found for height, weight and height velocity between perinatally infected children and seroreverters. Since auxological and hormonal evaluations run parallel to the clinical course of infection, these indices may be useful in monitoring disease progression.

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Section: Discussionmentioning

confidence: 99%

Growth impairment, IGF I hyposecretion and thyroid dysfunction in children with perinatal HIV‐1 infection

et al. 1994

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Selective vulnerability of the hippocampal pyramidal neurons to hypothyroidism in male and female rats

Madeira¹,

Sousa²,

Lima-Andrade³

et al. 1992

J of Comparative Neurology

122

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Thyroid hormone deficiency has long been considered to affect profoundly such cognitive functions as learning and memory, which are known to depend on the structural integrity of the hippocampal formation. Since we previously found that the number of granule cells of the dentate gyrus is reduced in hypothyroid animals, we decided to extend our observations to the pyramidal cells of the hippocampus in order to gain further insight into the effects of hypothyroidism upon the other neuronal links of the hippocampal trisynaptic circuitry, inasmuch as CA1 neurons are known to be particularly vulnerable to aggressive agents. Groups of 6 male and 6 female rats aged 30 and 180 days were analysed separately after being treated as follows: (1) hypothyroid from day 0 until day 30 (30-day-old hypothyroid group); (2) respective 30-day-old control; (3) hypothyroid from day 0 until day 180 (180-day-old hypothyroid group); (4) hypothyroid until day 30 and thenceforth maintained euthyroid (recovery group); (5) hypothyroid since day 30 (adult hypothyroid group); and (6) respective 180-day-old control. The volume of the pyramidal cell layer of the CA1 and CA3 regions and the numerical density of the respective neurons were evaluated, thereby allowing us to estimate the total number of pyramidal cells in each hippocampal region. The areal density and the mean nuclear volume of CA1 and CA3 pyramidal cells were also estimated. In the CA3 region, we found that hypothyroidism, whatever its duration and time of onset, induces a reduction in the volume of the pyramidal cell layer and a parallel increase in the numerical density of its neurons, without interfering with the total number of pyramidal cells. Conversely, in the CA1 region, thyroid hormone deficiency started either neonatally or during maturity was found to lead to a decrease in the total number of pyramidal cells. Reductions ranging between 14.2 and 22.5% were found in 30 and 180-day-old hypothyroid groups. The reestablishment of a euthyroid state did not ameliorate the referred neuronal loss. The present results support the view that hypothyroidism induces small alterations in the structural organization of the hippocampal CA3 region, contrary to what happens in CA1 in which neuronal death occurs. Furthermore, the data presented herein demonstrate that the total number of CA1 pyramidal cells displays sexual dimorphism that is not affected by thyroid hormone manipulations.(ABSTRACT TRUNCATED AT 400 WORDS)

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Reorganization of mossy fiber synapses in male and female hypothyroid rats: A stereological study

Madeira¹,

Paula‐Barbosa²

1993

J of Comparative Neurology

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Thyroid hormone deficiency has been reported to interfere with synaptogenesis, particularly in those regions of the brain where the neurons display a late and protracted histogenesis, although the extent of the synaptic alterations remains unknown. To provide detailed quantitative data on the effects of hypothyroidism upon synapses, a link of the hippocampal circuitry was selected: the contact between mossy fibers and dendritic excrescences of CA3 pyramidal cells (MF-CA3 synapses). Groups of six male and six female rats aged 30 and 180 days were analyzed separately after being treated as follows: (1) hypothyroid from day 0 until day 30 (30 day old hypothyroid group); (2) hypothyroid from day 0 until day 180 (180 day old hypothyroid group); (3) hypothyroid until day 30 and thenceforth maintained euthyroid (recovery group); and (4) and (5) 30 and 180 day old control groups, respectively. Timm staining, Golgi impregnation, and electron microscopy were employed to estimate the volume of the mossy fiber system, the number and size of mossy fiber boutons, and the number and related features of MF-CA3 synapses. The volume of the mossy fiber system and the number of synaptic boutons were reduced in all experimental groups. The total number of synapses was decreased in 30 day old hypothyroid rats, but did not differ among 180 day old animals. Postsynaptic densities were shorter in hypothyroid and recovery groups than in controls, although the reduction was not as marked in recovery rats as it was in hypothyroid animals. Structural alterations were noted in the pre- and postsynaptic compartments of MF-CA3 synapses of both 180 day old hypothyroid and recovery rats. These changes can be regarded as mechanisms of reorganization as they underlie the compensation for the hypothyroid-induced numerical reduction of synapses observed in 30 day old animals and enable a complete catch-up of their total number. However, synaptic reorganization was not fully achieved, as revealed by the reduction in the size of the synaptic sites in hypothyroid and recovery animals. Finally, we demonstrate that hypothyroidism did not interfere with the sex-related differences of MF-CA3 synapses described in normal rats.

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The Thyroid Gland

Cited by 4 publications

References 1,659 publications

Growth impairment, IGF I hyposecretion and thyroid dysfunction in children with perinatal HIV‐1 infection

Growth impairment, IGF I hyposecretion and thyroid dysfunction in children with perinatal HIV‐1 infection

Selective vulnerability of the hippocampal pyramidal neurons to hypothyroidism in male and female rats

Reorganization of mossy fiber synapses in male and female hypothyroid rats: A stereological study

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