The aim: To study the forms of anatomical variability of the external structure of the upper and lower parathyroid glands in the fetal period of human ontogenesis. Materials and methods: The study involved 48 specimens of human fetuses with 81,0-375,0 mm of crown-rump length (CRL). The study was conducted by means of macromicroscopic preparation, morphometry and variation statistics method. Results: The age and individual anatomical variability, complex way of development and formation of synotopic embryotropographic correlations of the upper and lower parathyroid glands in the prenatal period of human ontogenesis create numerous prerequisites for the emergence of variants of their external structure and topography in the fetuses of both different and the same age groups. Conclusions: There is a significant anatomical variability of the upper and lower parathyroid glands in 4-10-month-old fetuses, which is manifested by varieties of their shape and topical location. Aplasia of the upper parathyroid glands, which was found in two human fetuses aged 7 months, was due to the fetures of their organogenesis and the formation of syntopy in the embryonic and prefetal periods of their development. Parathyroid glands are mainly supplied with blood by the branches of the inferior thyroid artery. The branches of the upper thyroid artery and the arteries of adjacent organs: larynx, trachea and esophagus are involved in the blood supply. The right and left inferior thyroid veins are tributaries of the corresponding brachiocephalic vein, paired (right and left) superior and middle thyroid veins are those for the internal jugular vein.
Active implementation of perinatal prevention and treatment of congenital malformations requires modern approaches and methods of research of intrauterine development, the use of which is impossible without a comprehensive morphological study of development of the structure and topography of organs and structures of various systems in the early period of human ontogenesis. A priority task of the modern anatomy is the study of patterns of prenatal morphogenesis and syntopia of human endocrine glands. The purpose of the research was to study the peculiarities of the development and formation of the topography of the thyroid and parathyroid glands during the human embryonic period. Material and methods. The study was performed using microscopy of a series of consecutive histological sections of 18 human embryos of 4.0-13.5 mm parietal-coccygeal length and graphical reconstruction. Results and discussion. The thyroid gland forms as the epithelium cell’s protrusion along the midline between the I and II pharyngeal pockets, and appears on the 4th week of embryonic development. The rudiments of parathyroid glands in the form of epithelial protrusions of the dorsal part of the III and IV pharyngeal pockets appear during the 5th week of the development of fetus. In 6-week-old embryos, the thyroid gland enters into a complex syntopic relationships with adjacent organs and structures; herewith the topographic boundaries of the organ are not clearly defined. The growth of the thyroid gland goes along the common carotid arteries and gradually loses contact with the aortic arch. A diffuse vascular network is formed around the thyroid gland, which penetrates into it. It is clearly traced that the upper thyroid arteries originate from the external carotid arteries. At the end of the embryonic period the tempo of growth of thyroid gland acutely increases, the main variants of the thyroid gland's shape (with an isthmus and without an isthmus) can be defined. Conclusion. In the embryos of 4.0-4.5 mm parietal-coccygeal length, the thyroid gland's rudiment is detected as a protrusion of the epithelium along the midline between the I and II pharyngeal pockets, which begins to lose contact with the oropharyngeal cavity in embryos of 5.5-6.0 mm parietal-coccygeal length. Subsequently, appear close interrelations between the thyroid gland's rudiment and the arterial trunk. As a result of the formation of new syntopic connections of the thyroid gland’s rudiment with the IV pharyngeal arteries and the lower nodes of the vagus nerves, the thyroid gland's rudiment takes the form of a grooved plate that grows and models along the primitive aortic arch and localizes between the right and left common carotid arteries. The rudiments of the thyroid glands appear in embryos of 6.0-8.0 mm parietal-coccygeal length in the form of epithelial protrusions of the dorsal part of the III and IV pharyngeal pockets, from which in the future the lower and upper parathyroid glands will be formed, respectively. The critical periods of the thyroid and parathyroid glands development on the early stages of human ontogenesis are: 5th week – a period of intensive formation of the rudiments of the thyroid and parathyroid glands, and 6th week – the formation of laryngeal cartilages and cellular structures of the neck
The results of applying X-ray investigation methods to confirm effectiveness of the developed osteoplastic combination including multipotent mesenchymal stromal cells of adipose tissue, which was used to fill bone defects in operated patients, have been elusidated. Participants and methods. The study was conducted at the Department of Surgical Dentistry and Maxillofacial Surgery, Bukovinian State Medical University, Chernivtsi, Ukraine. To determine the density of bone tissue, CT scanning was done for 26 patients when replacing the bone defect with «Kolapan–L» (group A), for 28 people during the augmentation with an osteoplastic combination containing multipotent mesenchymal stromal cells of adipose tissue (group B), and for 25 patients where bone defect healing occurred spontaneously (group C). The study was conducted after the surgical operations (in 3-5-day, 3-, 6-, 12-month follow up period. We have found out the patients of group B who received the preparation «Kolapan–L» to fill bone defects in combination with multipotent mesenchymal stromal cells of adipose tissue and platelet-rich plasma demonstrate completed osteoregeneratis with newly formed bone tissue without granules of osteoplastic material in 6-8 months after the surgical intervention. In the patients of group A, who received the preparation «Kolapan–L» to replace bone defect, a complete osteoregeneration was observed in small and medium defects in 6-8 months, and more pronounced outcomes (more than 2.0 mm) were seen in 12-16 months. In the patients of group C (spontaneous healing), small bone defects were observed after 9-11 months the healing, while significant defects showed no complete tissues regeneration even in 12 month period. The results have demonstrated that in 12 month period, the patients of group B have the average density of osteoregenerate equalled 1036,69±55,53 HU that is 1.5 times and 1.8 times more than those values in the group A, p<0.01, and in the group B, p<0.05, p1<0.01, respectively.
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