Ultrasonographic assessment of the thyroid gland and adjacent anatomic structures in Indo-Pacific bottlenose dolphins (Tursiops aduncus)

Kot, Bcw; Ying, Michael; Brook, Fiona; Kinoshita, R; Cheng, Sammy Chi Him

doi:10.2460/ajvr.73.11.1696

Cited by 14 publications

(9 citation statements)

References 69 publications

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“…The interface between thyroid gland cells and the colloid exhibit high acoustic impedance, causing high frequency acoustic waves to be reflected back to the transducer. The present study proved that the dolphin thyroid gland cells were found to be smaller than the normal human thyroid gland cells, resulting in a lower echogenicity [23]. A dolphin thyroid gland with hypoechoic and isoechoic appearances is thus considered to be normal.…”

Section: Discussionsupporting

confidence: 56%

“…Individual differences in the ultrasonographic appearance and volume of the thyroid gland were noted in this species [23]. Different cetacean species have variations in thyroid gland morphology and function, which are associated with demographic variables, physiological cycles and health status [10],[11],[23]–[25]. Determining volume is important in assessing the development and involution of the thyroid gland, but volume estimation is also important in stereological studies.…”

Section: Introductionmentioning

confidence: 87%

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Stereology of the Thyroid Gland in Indo-Pacific Bottlenose Dolphin (Tursiops aduncus) in Comparison with Human (Homo sapiens): Quantitative and Functional Implications

2013

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The mammalian thyroid gland maintains basal metabolism in tissues for optimal function. Determining thyroid volume is important in assessing growth and involution. Volume estimation is also important in stereological studies. Direct measurements of colloid volume and nuclear-to-cytoplasmic ratio of the follicular cells may provide important information about thyroid gland function such as hormone storage and secretion, which helps understand the changes at morphological and functional levels. The present study determined the colloid volume using simple stereological principle and the nuclear-to-cytoplasmic ratio of 4 Indo-Pacific bottlenose dolphins and 2 human thyroid glands. In both dolphin and human thyroid glands, the size of the follicles tended to be quite variable. The distribution of large and small follicles within the thyroid gland was also found to be random in both the dolphin and human thyroid gland; however, the size of follicles appeared to decrease as a function of increasing age in the dolphin thyroid gland. The mean colloid volume of the dolphin thyroid gland and human thyroid gland was 1.22×105 µm3 and 7.02×105 µm3 respectively. The dolphin and human subjects had a significant difference in the mean colloid volume. The mean N/C ratio of the dolphin thyroid follicular epithelia and human follicular epithelia was 0.50 and 0.64 respectively. The dolphin and human subjects had a significant difference in the mean N/C ratio. This information contributes to understanding dolphin thyroid physiology and its structural adaptations to meet the physical demands of the aquatic environment, and aids with ultrasonography and corrective therapy in live subjects.

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Section: Discussionsupporting

confidence: 56%

Section: Introductionmentioning

confidence: 87%

Stereology of the Thyroid Gland in Indo-Pacific Bottlenose Dolphin (Tursiops aduncus) in Comparison with Human (Homo sapiens): Quantitative and Functional Implications

2013

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“…Ultrasonography is an effective imaging tool for the assessment of thyroid glands and is commonly used to screen for pathological changes in human thyroid tissue [30,31] . In recent years, its applications in several animal species, such as horses [32] , dogs [33] , dolphins [34] , and mice [17] , have been reported. Homogeneity and hyperechoic echotexture are the basic characteristics of normal parenchyma in thyroid tissue.…”

Section: Discussionmentioning

confidence: 99%

Dietary high-fat lard intake induces thyroid dysfunction and abnormal morphology in rats

et al. 2014

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Aim: Excess dietary fat intake can induce lipotoxicity in non-adipose tissues. The aim of this study was to observe the effects of dietary high-fat lard intake on thyroid in rats. Methods: Male Sprague-Dawley rats were fed a high-fat lard diet for 24 weeks, and then the rats were fed a normal control diet (acute dietary modification) or the high-fat lard diet for another 6 weeks. The serum lipid profile, total thyroxine (TT4), free thyroxine (FT4) and thyrotropin (TSH) levels were determined at the 12, 18, 24 and 30 weeks. High-frequency ultrasound scanning of the thyroid glands was performed at the 24 or 30 weeks. After the rats were sacrificed, the thyroid glands were collected for histological and immunohistochemical analyses. Results: The high-fat lard diet significantly increased triglyceride levels in both the serum and thyroid, and decreased serum TT4 and FT4 levels in parallel with elevated serum TSH levels. Ultrasonic imaging revealed enlarged thyroid glands with lowered echotexture and relatively heterogeneous features in the high-fat lard fed rats. The thyroid glands from the high-fat lard fed rats exhibited enlarged follicle cavities and flattened follicular epithelial cells under light microscopy, and dilated endoplasmic reticulum cisternae, twisted nuclei, fewer microvilli and secretory vesicles under transmission electron microscopy. Furthermore, the thyroid glands from the highfat lard fed rats showed markedly low levels of thyroid hormone synthesis-related proteins TTF-1 and NIS. Acute dietary modification by withdrawal of the high-fat lard diet for 6 weeks failed to ameliorate the high-fat lard diet-induced thyroid changes. Conclusion: Dietary high-fat lard intake induces significant thyroid dysfunction and abnormal morphology in rats, which can not be corrected by short-term dietary modification.

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“…In aquatic animal medicine, ultrasound is a very helpful and easy-to-use tool for investigation and diagnosis, particularly in the study of the coelomic organs in chelonians (Penninck et al 1991;Martorell et al 2004;Valente et al 2007;Margheri et al 2011;Kot et al 2012;Macri et al 2013a;Macri et al2013b;Macri et al 2015). Regarding chelonian reproduction, ultrasound examinations have proven to be an efficient non-invasive method for monitoring ovarian development and activity in sea turtles and reproductive activity in adult males (Rostal et al 1990;Valente et al 2007;Manire et al 2008).…”

mentioning

confidence: 99%

Clinical ultrasonography in loggerhead sea turtles (Caretta caretta): imaging of pathological features

Majo¹,

Macrı̀²,

Masucci³

et al. 2016

Vet. Med. - Czech

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Ultrasound scans were used to image pathological features in sea turtles. Scans were carried out in 19 loggerhead sea turtles, weighing from 2 to 21 kg, during the course of clinical examinations using 3.5 and 7.5 MHz sector transducers. The examination was performed after placing turtles in dorsal recumbency. Turtles were manually restrained and, in order to find the most suitable acoustic windows, were held down either by their heads (left and right cervicobrachial windows), front flippers (left and right axillary windows) or back flippers (left and right prefemoral and postfemoral windows). The right and left cervicobrachial windows allowed visualisation of the liver and gallbladder; the stomach was localised through the left prefemoral acoustic window; the intestinal loops were observed through the left and right prefemoral acoustic windows; the bladder was identified through both prefemoral acoustic windows. The pathological findings were as follows: idiopathic ileus, an intestinal linear foreign body and smooth muscle hypertrophy, presence of calculi and sediment in the gallbladder. These results highlight the importance of ultrasound examination along with clinical examination in sea turtles for the evaluation of coelomic pathologies.

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Ultrasonographic assessment of the thyroid gland and adjacent anatomic structures in Indo-Pacific bottlenose dolphins (Tursiops aduncus)

Abstract: Ultrasonography provided a reliable and repeatable method for evaluation of thyroid glands and adjacent anatomic structures in live dolphins.

Cited by 14 publications

References 69 publications

Stereology of the Thyroid Gland in Indo-Pacific Bottlenose Dolphin (Tursiops aduncus) in Comparison with Human (Homo sapiens): Quantitative and Functional Implications

Stereology of the Thyroid Gland in Indo-Pacific Bottlenose Dolphin (Tursiops aduncus) in Comparison with Human (Homo sapiens): Quantitative and Functional Implications

Dietary high-fat lard intake induces thyroid dysfunction and abnormal morphology in rats

Clinical ultrasonography in loggerhead sea turtles (Caretta caretta): imaging of pathological features

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