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The Role of Thyroid Hormone on the Development of Endothermy in White Leghorn Chickens [Gallus gallus]

Description: As chickens hatch, there is a rapid change in their physiology and metabolism associated with attaining endothermy. It is thought that thyroid hormones (TH) play a major role in regulating developmental changes at hatching. In birds, TH regulates skeletal muscle growth, which has a direct impact on the chick's ability to thermoregulate via shivering thermogenesis. To better understand the role of TH in the timing of hatching, development of thermogenic capacity, and metabolic rate, we manipulated plasma TH levels in chicken embryos beginning at 85% development (day 17 of a 21 day incubation) with either thyroperoxidase inhibitor methimazole (MMI) or supplemental triiodothyronine (T3). After TH manipulation, we characterized O2 consumption and body temperature in the thermal neutral zone and during gradual cooling. Externally pipped embryos and 1 day post hatch (dph) chicks were cooled from 35 to 15°C. Manipulation of TH altered the timing of hatching, accelerating hatching under hyperthyroid conditions and decelerating hatching with hypothyroid conditions. Cohen's d revealed a large effect size on body temperature (Tb) of EP embryos of hypothyroid animals when compared to euthyroid animals in environmental temperatures of 32°C to 15°C, which was not seen in 1dph animals. Hyperthyroid EP animals were able to maintain metabolic rate over a wider range of ambient temperatures compared to control and hypothyroid animals, but these differences disappeared in 1dph animals. Here, we find that elevating TH levels prior to hatching accelerated hatching and the animal's thermogeneic ability to respond to cooling, but these differences disappear with age.
Date: August 2018
Creator: Rippamonti, Jessica D
Partner: UNT Libraries

Thyroid ultrastructural changes induced by hypothermia

Description: Investigations have shown that the hypothalamus and pituitary respond to decreases in body temperature by stimulating the thyroid gland to release T3 and T4 hormones. This study was designed to investigate ultrastructural changes of the thyroid gland induced by hypothermia. The ultrastructural changes produces by stimulation by Thyroid Stimulating Hormone were also examined as an adjunct to the hypothermic stimulation of the gland.
Date: August 1979
Creator: Kent, James Simpson
Partner: UNT Libraries

The Hypothermic Perfusion of the Isolated Thyroid Gland and Its Release of T₃ And T₄

Description: Investigations have shown that the hypothalamus and pituitary respond to decreases in body temperature by stimulating thyroid release of T_3 and T_4 . This study was designed to bypass the control of the hypothalamus and pituitary gland and investigate the direct effect of temperature on the thyroid gland. Hypothermia was by an in vivo isolated perfusion of the thyroid gland. Radio-immunoassay was used to measure T_3 and T_4 concentrations. Significant increases were observed in animals perfused between 36º and 25ºc. These results indicate that the thyroid gland is directly effected by decreased temperature and that it is capable of exerting control over body temperature independent of the hypothalamus and pituitary gland. Lower perfusion temperatures produced no significant increases.
Date: December 1976
Creator: Haenke, Richard F.
Partner: UNT Libraries

The Role of Thyroid Hormone across Avian Development Spectrum: Investigations on Systemic Development, Metabolism and Ontogeny of Endothermy

Description: Achievement of endothernic capacity is vital for independence from ambient temperature changes, sustained activity, optimal biochemical reactions and optimization of parental care. During early avian development, the core tenets of transition from ectothermy to endothermy are development of metabolic capacity (oxygen consumption, mitochondrial bioenergetics), enhanced cardiovascular function (heart rate and cardiac output), pulmonary ventilation and thermogenic capacity. Thyroid hormones, particularly T3, are key metabolic regulators of basal metabolism, thermogenesis, pulmonary ventilation and mitochondrial respiration. Thyroid hormone fluctuation patterns during both precocial and altricial avian endothermic transition suggest a prominent role in maturation of endothermy, cardiovascular, respiratory and skeletal muscle physiology. This body of work explores effects of T3 manipulations in two avian species: the precocial Pekin duck and the altricial Red-winged Blackbird. Increased plasma T3 during late incubation resulted in increased cardiac mass, elevated resting and intrinsic heart rate, intrinsic mean arterial pressure, increased cholinergic tone and blunted alpha-adrenergic tone in the precocial Pekin duck. In both Pekin duck and Red-winged blackbird, plasma T3 levels correlated with changes in the trajectory of endothermic ontogeny, systemic oxygen consumption, thermogenesis, maturation of pulmonary ventilatory function, altered growth and effects on skeletal and cardiac mitochondrial bioenergetics. These observations support the role of thyroid hormones as metabolic and developmental regulators at the time of attainment of endothermy during the perinatal period in precocial and altricial avian species. Insights into the role of thyroid hormone as a metabolic and development regulator at the time of avian endothermic attainment provide a more thorough understanding of metabolic and physical transitions a hatchling bird must undergo to reach the adult endothermic phenotype. Such insights also deepen understanding of the complex role thyroid hormones play in homeostasis and offer implications about the evolutionary history of endothermic capacity.
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Date: August 2017
Creator: Sirsat, Tushar S
Partner: UNT Libraries

Kinase Expression and Chromosomal Rearrangements in Papillary Thyroid Cancer Tissues: Investigations at the Molecular and Microscopic Levels

Description: Structural chromosome aberrations are known hallmarks of many solid tumors. In the papillary form of thyroid cancer (PTC), for example, activation of the receptor tyrosine kinase (RTK) genes, ret or the neurotrophic tyrosine kinase receptor type I (NTRK1) by intra- or interchromosomal rearrangements have been suggested as a cause of the disease. The 1986 accident at the nuclear power plant in Chernobyl, USSR, led to the uncontrolled release of high levels of radioisotopes. Ten years later, the incidence of childhood papillary thyroid cancer (chPTC) near Chernobyl had risen by two orders of magnitude. Tumors removed from some of these patients showed aberrant expression of the ret RTK gene due to a ret/PTC1 or ret/PTC3 rearrangement involving chromosome 10. However, many cultured chPTC cells show a normal G-banded karyotype and no ret rearrangement. We hypothesize that the 'ret-negative' tumors inappropriately express a different oncogene or have lost function of a tumor suppressor as a result of chromosomal rearrangements, and decided to apply molecular and cytogenetic methods to search for potentially oncogenic chromosomal rearrangements in Chernobyl chPTC cases. Knowledge of the kind of genetic alterations may facilitate the early detection and staging of chPTC as well as provide guidance for therapeutic intervention.
Date: July 7, 2009
Creator: Weier, Heinz-Ulrich; Kwan, Johnson; Lu, Chun-Mei; Ito, Yuko; Wang, Mei; Baumgartner, Adolf et al.
Partner: UNT Libraries Government Documents Department


Description: A new technique for measuring the radioiodine content of the human thyroid in vivo with nanocurie amounts of I/sup 131/ and I/sup 125/ is described. The technique gives a measure of the thickness of neck tissue over the thyroid; values of 0.4 and 2.0 cm have been found in the subjects studied thus far. Results on 6 normal adults show uptake at 7 days after oral ingestion varies between 15 and 29%, with biological half times between 27 days and infinity. Results on 8 normal children (ages 4 to 10 yr) show little or no difference from adults as far as the data extend (15 days post oral ingestion). Uptakes vary between 9.5 and 27%, and biological half times are long compared to the 8-day physical haif life. (auth)
Date: January 1, 1963
Creator: Van Dilla, M.A. & Fulwyler, M.J.
Partner: UNT Libraries Government Documents Department

Low Dose Gamma Irradiation Potentiates Secondary Exposure to Gamma Rays or Protons in Thyroid Tissue Analogs

Description: We have utilized our unique bioreactor model to produce three-dimensional thyroid tissue analogs that we believe better represent the effects of radiation in vivo than two-dimensional cultures. Our thyroid model has been characterized at multiple levels, including: cell-cell exchanges (bystander), signal transduction, functional changes and modulation of gene expression. We have significant preliminary data on structural, functional, signal transduction and gene expression responses from acute exposures at high doses (50-1000 rads) of gamma, protons and iron (Green et al., 2001a; 2001b; 2002a; 2002b; 2005). More recently, we used our DOE funding (ending Feb 06) to characterize the pattern of radiation modulated gene expression in rat thyroid tissue analogs using low-dose/low-dose rate radiation, plus/minus acute challenge exposures. Findings from these studies show that the low-dose/low-dose rate “priming” exposures to radiation invoked changes in gene expression profiles that varied with dose and time. The thyrocytes transitioned to a “primed” state, so that when the tissue analogs were challenged with an acute exposure to radiation they had a muted response (or an increased resistance) to cytopathological changes relative to “un-primed” cells. We measured dramatic differences in the primed tissue analogs, showing that our original hypothesis was correct: that low dose gamma irradiation will potentiate the repair/adaptation response to a secondary exposure. Implications from these findings are that risk assessments based on classical in vitro tissue culture assays will overestimate risk, and that low dose rate priming results in a reduced response in gene expression to a secondary challenge exposure, which implies that a priming dose provides enhanced protection to thyroid cells grown as tissue analogs. If we can determine that the effects of radiation on our tissue analogs more closely resemble the effects of radiation in vivo, then we can better estimate the risks and modify assign limits to radiation worker and astronauts. ...
Date: May 25, 2006
Creator: Green, Lora M
Partner: UNT Libraries Government Documents Department

Application-Specific Things Architectures for IoT-Based Smart Healthcare Solutions

Description: Human body is a complex system organized at different levels such as cells, tissues and organs, which contributes to 11 important organ systems. The functional efficiency of this complex system is evaluated as health. Traditional healthcare is unable to accommodate everyone's need due to the ever-increasing population and medical costs. With advancements in technology and medical research, traditional healthcare applications are shaping into smart healthcare solutions. Smart healthcare helps in continuously monitoring our body parameters, which helps in keeping people health-aware. It provides the ability for remote assistance, which helps in utilizing the available resources to maximum potential. The backbone of smart healthcare solutions is Internet of Things (IoT) which increases the computing capacity of the real-world components by using cloud-based solutions. The basic elements of these IoT based smart healthcare solutions are called "things." Things are simple sensors or actuators, which have the capacity to wirelessly connect with each other and to the internet. The research for this dissertation aims in developing architectures for these things, focusing on IoT-based smart healthcare solutions. The core for this dissertation is to contribute to the research in smart healthcare by identifying applications which can be monitored remotely. For this, application-specific thing architectures were proposed based on monitoring a specific body parameter; monitoring physical health for family and friends; and optimizing the power budget of IoT body sensor network using human body communications. The experimental results show promising scope towards improving the quality of life, through needle-less and cost-effective smart healthcare solutions.
Date: May 2018
Creator: Sundaravadivel, Prabha
Partner: UNT Libraries


Description: An accidental release of gaseous fission products from an ORR fused salt capsule, containing 26 mg. of U/sup 235/, was postulated and the resuiting hazard estimated by calculating the maximum external and internal dose an individual could receive from exposure to the gaseous fission products and their decay products. Assuming all the contained gaseous fission produets are released, the resulting external and internal dosc, to organs other than the thyroid, arc insignificant. The dose to the thyroid by radioiodine is considered to be significant. By retaining at least 90% of the iodine isotopes in the experiment system through use of an iodine trap, a large reduction in both the external whole body and internal thyroid doses may be achieved. Therefore, assuming an iodine trap is utilized, it appears that the consequences of am accidental gaseous fission product release from an ORR fused salt capsule experiment would not be serious. (auth)
Date: April 24, 1959
Creator: Adams, R.E. & Browning, W.E.
Partner: UNT Libraries Government Documents Department

Molecular cytogenetic characterization of a human thyroid cancercell line

Description: The incidence of papillary thyroid carcinoma (PTC) increases significantly after exposure of the head and neck region to ionizing radiation, yet we know neither the steps involved in malignant transformation of thyroid epithelium nor the specific carcinogenic mode of action of radiation. Such increased tumor frequency became most evident in children after the 1986 nuclear accident in Chernobyl, Ukraine. In the twelve years following the accident, the average incidence of childhood PTCs (chPTC) increased over one hundred-fold compared to the rate of about 1 tumor incidence per 10{sup 6} children per year prior to 1986. To study the etiology of radiation-induced thyroid cancer, we formed an international consortium to investigate chromosomal changes and altered gene expression in cases of post-Chernobyl chPTC. Our approach is based on karyotyping of primary cultures established from chPTC specimens, establishment of cell lines and studies of genotype-phenotype relationships through high resolution chromosome analysis, DNA/cDNA micro-array studies, and mouse xenografts that test for tumorigenicity. Here, we report the application of fluorescence in situ hybridization (FISH)-based techniques for the molecular cytogenetic characterization of a highly tumorigenic chPTC cell line, S48TK, and its subclones. Using chromosome 9 rearrangements as an example, we describe a new approach termed ''BAC-FISH'' to rapidly delineate chromosomal breakpoints, an important step towards a better understanding of the formation of translocations and their functional consequences.
Date: January 4, 2006
Creator: Weier, Heinz-Ulrich G.; Tuton, Tiffany B.; Ito, Yuko; Chu, LisaW.; Lu, Chung-Mei; Baumgartner, Adolf et al.
Partner: UNT Libraries Government Documents Department

BAC-FISH assays delineate complex chromosomal rearrangements in a case of post-Chernobyl childhood thyroid cancer

Description: Structural chromosome aberrations are known hallmarks of many solid tumors. In the papillary form of thyroid cancer (PTC), for example, activation of the receptor tyrosine kinase (RTK) genes, RET and neurotrophic tyrosine kinase receptor type I (NTRK1) by intra- and interchromosomal rearrangements has been suggested as a cause of the disease. However, many phenotypically similar tumors do not carry an activated RET or NTRK-1 gene or express abnormal ret or NTRK-1 transcripts. Thus, we hypothesize that other cellular RTK-type genes are aberrantly expressed in these tumors. Using fluorescence in situ hybridization-based methods, we are studying karyotype changes in a relatively rare subgroup of PTCs, i.e., tumors that arose in children following the 1986 nuclear accident in Chernobyl, Ukraine. Here, we report our technical developments and progress in deciphering complex chromosome aberrations in case S48TK, an aggressively growing PTC cell line, which shows an unusual high number of unbalanced translocations.
Date: March 9, 2009
Creator: Kwan, Johnson; Baumgartner, Adolf; Lu, Chun-Mei; Wang, Mei; Weier, Jingly F.; Zitzelsberger, Horst F. et al.
Partner: UNT Libraries Government Documents Department