Single-layered Epithelium Research Articles

Revisiting the human umbilical cord epithelium. An atypical epithelial sheath with distinctive features.

The umbilical cord epithelium (UCE) is the surface tissue that covers the umbilical cord (UC). It is widely considered a single-layered epithelium composed of squamous or cuboidal cells, which are in constant contact with amniotic fluid. The objective of this study was to elucidate the distinctive structural characteristics and abundance of specific proteins in this unique epithelium, many of which have not been previously demonstrated. Samples of the UC were obtained from term pregnancies (n = 12) and processed for examination using stereo, light, electron, and 3D high-resolution confocal microscopy. Sections displayed a range of stratification, ranging from a single squamous layer to 4-5 layers of round/cuboid cells, challenging the notion of considering it as a single-layered structure. Cells are located on a well-developed basement membrane (BM), as evidenced by the expression of BM-specific proteins and PAS staining. The cells possess distinctive cytoplasmic domains that are tightly bound to each other by desmosomes and interdigitating anchoring surfaces. Desquamations and limited organelles suggest that the cells have reached the final stages of differentiation and are no longer actively synthesizing proteins, despite maintaining stratification-specific expression levels of cytoskeletal, junctional, receptor, and stem cell proteins. Although definitive keratinization was not observed, the distribution of proteins and the distinctive structural organization of the single/multi-layered cells suggest that they exhibit plasticity, likely due to adaptive mechanisms in response to chemical and/or mechanical stimuli during fetal development. These structural alterations may facilitate the active transportation of soluble ingredients between the amniotic fluid and cord blood through an intercellular route.

Morphological structure of salivary glands, alimentary canal, and Malpighian tubules in adult Eurydema spectabilis Horváth, 1882 (Heteroptera, Pentatomidae).

Eurydema spectabilis (Heteroptera: Pentatomidae) has a piercing-sucking mouth type and feeds on plant sap. In this study, the morphological structure of the salivary glands, alimentary canal, and Malpighian tubules of E. spectabilis was examined using light and scanning electron microscopy. Salivary glands consist of the principal and accessory salivary glands. In E. spectabilis, digestion begins in the mouth and ends in the anus. Alimentary canal is divided into three parts: foregut, midgut, and hindgut. The foregut consists of pharynx, esophagus, and proventriculus. The esophagus connects to the proventriculus and resembles a narrow tube. The wall of the proventriculus has a recessed structure and is surrounded by a single cylindrical layer of epithelium and muscle. The midgut is divided into three regions: the first, second, and third ventricles (V1-V3). V1 and V2 consist of single-layered cylindrical epithelium. V3 contains a single layer of cuboidal epithelium. Gastric caeca were found in the midgut. The hindgut consisted of a pylorus followed by a well-developed rectum. The wall of the rectum consists of a single-layer cuboidal epithelium and muscle. Its lumen contains numerous bacteria and uric acid crystals. The pylorus consists of a single-layered cylindrical epithelium. It is also the origin of Malpighian tubules. Malpighian tubules consist of two regions: proximal and distal. The morphological structure of the salivary glands, alimentary canal, and Malpighian tubules of E. spectabilis, which has not been studied before, was examined and discussed in comparison with other orders. It is also aimed to contribute to future studies. RESEARCH HIGHLIGHTS: In E. spectabilis, the salivary glands are divided into principal and accessory salivary glands. Microvilli and numerous secretory granules were found in Malpighian tubules. Numerous uric acid crystals and bacteria were found in the rectum lumen.

The fate of secretory cells during intestinal homeostasis, regeneration, and tumor formation is regulated by Tcf4.

The single-layer epithelium of the gastrointestinal tract is a dynamically renewing tissue that ensures nutrient absorption, secretory and barrier functions and is involved in immune responses. The basis for this homeostatic renewal is the Wnt signaling pathway. Blocking this pathway can lead to epithelial damage, while its abnormal activation can result in the development of intestinal tumors. In this study, we investigated the dynamics of intestinal epithelial cells and tumorigenesis using a conditional mouse model. Using single-cell and bulk RNA sequencing and histological analysis, we elucidated the cellular responses following the loss of specific cell types. We focused on the fate of cells in the lower parts of the intestinal crypts and the development of colon adenomas. By partially inactivating the transcription factor Tcf4, a key effector of the Wnt signaling pathway, we analyzed the regeneration of isolated hyperproliferative foci (crypts). Our results suggest that the damaged epithelium is not restored by a specific regeneration program associated with oncofetal gene production, but rather by a standard homeostatic renewal pathway. Moreover, disruption of Tcf4 in secretory progenitors resulted in a significant shift in the cell lineage from Paneth cells to goblet cells, characterized by morphological changes and loss of Paneth cell-specific genes. We also found that hyperactivation of the Wnt signaling pathway in colonic adenomas correlated with the upregulation of genes typical of Paneth cells in the intestine, followed by the emergence of secretory tumor cells producing the Wnt3 ligand. The absence of Tcf4 led to a phenotypic shift of the tumor cells towards goblet cells. Our study presents a new model of epithelial regeneration based on the genetically driven partial elimination of intestinal crypts. We highlight the critical role of Tcf4 in the control of cell lineage decisions in the intestinal epithelium and colon tumors.

Histopathological findings of anterior lens capsule in pediatric cataract.

To investigate the histopathological findings of the anterior lens capsule in pediatric patients who had surgery for cataracts. This study is a prospective interventional study. Anterior capsule tissue samples that were obtained by the anterior capsulotomy method during phacoemulsification surgery were fixed and examined under a transmission electron microscope. Twenty-two eyes of 19 patients who were diagnosed with congenital and juvenile cataracts were included in this study. Five patients had associated systemic diseases, including hydrocephalus, cerebral palsy, prematurity, juvenile myelomonocytic leukemia, and Down's syndrome. Electron microscopic evaluation demonstrated single-layered epithelium under the capsule, degenerated organelles with round-oval and prismatic-oval nuclei, and degenerated mitochondria and heterochromatin-rich nuclei. In the case with cerebral palsy, collagen fibrils of the connective tissue and fibroblast-like cells were observed replacing the epithelium that should be underneath the capsule in both eyes, and there was a disorganized distribution of collagen fibrils and vacuole structures in the cytoplasm of fibroblast-like cells. Similar histopathological findings were found in pediatric cataracts with or without systemic disease except in one cerebral palsy case. The absence of lens epithelium may have been a result of degeneration in this patient, and this can be attributed to the presence of systemic inflammation and gliosis in cerebral palsy. The absence of lens epithelium can play a role in the development of dense subcapsular fibrosis and cataract formation.

In Vivo Engineering and Transplantation of Axially Vascularized and Epithelialized Flaps in Rats.

The arteriovenous loop (AVL) model allows the in vivo engineering of axially vascularized flaps, the so-called AVL flaps. Although AVL flaps can be transplanted microsurgically to cover tissue defects, they lack an epithelial layer on the surface. Therefore, the objective of this study was to engineer axially vascularized AVL flaps with an accompanying epithelial layer for local defect reconstruction. In this study, AVLs were established in 20 male Lewis rats. Minimally invasive injection of keratinocytes onto the surface of the AVL flaps was performed on postoperative day (POD) 21. AVL flaps were explanted from 12 rats on POD 24 or POD 30, then the epithelium formed by the keratinocytes on the surface of the flaps was evaluated using immunofluorescence staining. In six other rats, the AVL flap was locally transposed to cover a critical defect in the rats' leg on POD 30 and explanted for analysis on POD 40. In two control rats, sodium chloride was applied instead of keratinocytes. These control flaps were also transplanted on POD 30 and explanted on POD 40. Our results revealed that 3 days after keratinocyte application, a loose single-layered epithelium was observed histologically on the AVL flaps surface, whereas after 9 days, a multilayered and structured epithelium had grown. The epithelium on the transplanted AVL flaps showed its physiological differentiation when being exposed to an air-liquid interface. Histologically, a layered epithelium identical to the rats' regular skin was formed. In the sodium chloride control group, no epithelium had been grown. This study clearly demonstrates that axially vascularized AVL flaps can be processed in the subcutaneous chamber by minimally invasive injection of keratinocytes. Thus, AVL flaps with an intact epithelial layer were engineered and could be successfully transplanted for local defect coverage in a small animal model.

ULTRASTRUCTURAL FEATURES OF THE DIGESTIVE SYSTEM OF THE ADULT HELMINTH Heterakis gallinarum SCHRANK, 1788 (NEMATODA: HETERAKIDAE)

Species of the Heterakidae family are similar in appearance. These signs cause difficulties in determining the systematic position of the species. For this purpose, the digestive organs of adult H. gallinarum nematode were studied at the ultrastructural levels by light and electron microscopic methods. The obtained results were compared with the structures of other species of the family. The digestive organs of adult H. gallinarum nematode are divided into 3 parts - stomodeum, intestine and proctodeum. The esophagus in turn is divided into procorpus, metacorpus and bulb. Its wall consists of basement membrane, muscle cells and cuticle. In the bulb, the muscle cells are large and relatively large in number. The intestine is divided into ventricular, middle and prerectal areas. It consists of a thick basement membrane, a single-layered epithelium with microvillas. Epithelial cells are divided into 5 areas that differ from each other according to their structure. The smooth membranes of the epithelial cells create a barrier connection with each other. Sphincter cells are noted at the end of the intestine. After that part, the rectum was found in females and the cloaca in males nematodes. The lumen of both is covered with cuticle. The ultrastructural features of the digestive organs of the nematode H. gallinarum are consistent with the main systematic features of the family.

Features of the microstructural organization of the small intestine in weaning piglets

The material for the study was fragments of the wall of the duodenum, jejunum and ileum obtained from five piglets at the age of 41 days. The selected tissue samples were fixed during the day in a 10.0% solution of neutral formalin. Their further processing in order to obtain histological sections was carried out according to a generally accepted method. The obtained histological sections were stained with hematoxylin and eosin and according to Van Gieson. All morphometric data obtained were subjected to statistical processing.It was found that in the studied animals, the small intestine is arranged in accordance with the general plan of structure peculiar to mammals. Its wall is formed by the mucous membrane, submucosal base, as well as muscle and serous mem-branes. The epithelial layer of the mucous membrane of the small intestine is represented by a single-layer prismatic epithelium, which is a highly dynamic structure that quickly reacts to changing loads due to the high rate of cell renewal. The bulk of the epithelial layer is represented by edged enterocytes (about 90.0% of the entire cell population). In addition to them, goblet-shaped, endocrine, Panethovian, proliferating and stem cells take part in the formation of the epithelial lining of the small intestine.

Comparative light and scanning electron microscopic studies of the lenses in the insectivorous bat (Pipistrellus kuhlii) and Egyptian fruit bat (Rousettus aegyptiacus).

Bats have the ability to fly without eye application in the darkness. In this study, we aimed to characterize the functional and structural acclimations of the lenses of two common bats with a various lifestyle in the Egyptian environment: the insectivorous bat (IB) (Pipistrellus kuhlii) and Egyptian fruit bat (FB) (Rousettus aegyptiacus). From each species, seven lenses were extracted from adult eyes. The scanning electron microscopic (SEM) and light microscopic examination of the lens were carried out. FB lenses were made up primarily of fiber cells and sheets, which were encapsulated by a thin collagenous capsule and covered by single epithelial layer anteriorly. On the other hand, the IB lens had two poles and was visibly oval shaped. Both lenses had epithelial cells of the same cuboidal form that were subjected to continuous division and differentiation into new fiber cells at the center. SEM revealed that the normal FB lens had regularly organized shells of fiber cells of intact lens fibers which were connected by membrane interdigitations with different shapes mainly ball-and-socket junctions through the superficial cortical fiber cells. The IB lens was composedof parallel, evenly spaced fibers with various types of interdigitations between fibers that can be seen and increased close to the middle region revealing tiny bumps along the scrubby portions and sockets and balls in the center of the wide portions. Near the center of both lenses, there were large interlocking paddles with little and lengthy protrusions along their short sides. In conclusion, our study discovered several ultrastructural and structural variations among the investigated species. The detection of specialized membrane interdigitations with different shapes protruding from the lens fiber sheets is considered the most characteristic of the FB lens. RESEARCH HIGHLIGHTS: FB lens has more organized sheets of fibers parallel to each other than IB lens. Different shapes of interdigitations protruded from the FB lens have been detected. Interlocking paddles, balls, and sockets with tongue-like fiber flabs are characteristic to FB lens.

Ultrastructural characterization of the midgut in the short-faced scorpionfly Panorpodes with mysterious feeding habit (Mecoptera: Panorpodidae)

The midgut of insects as the function core of the alimentary canal usually exhibits diverse morphology depending on their different food types. Mecoptera is an ideal model for comparative studies of the midgut because this small primitive holometabolous group possesses diverse feeding habits. In this study, the midgut of Panorpodes kuandianensis adult was investigated using light and transmission electron microscopy. The result shows that the midgut of P. kuandianensis is a simple straight tube. The single-layered epithelium is composed of regenerative cells and digestive cells. The regenerative cells are grouped in nidi along the epithelium base with high electron-dense cytoplasm and limited organelles. The regenerative cells undergoing differentiation elongate toward the lumen and accumulate numerous mitochondria in the apical region, gradually forming new digestive cells. The columnar digestive cells are the predominant cell type, with distinct regionalization in organelles distribution. Based on the ultrastructural characteristics of the different cells, the functions of the midgut epithelium of P. kuandianensis and the possible feeding habit are discussed. The results could provide a foundation for further understanding the digestive physiology and phylogeny of Panorpodes.

Ultra-structural organization of the gallbladder mucous membrane of Anglo-Nubian goat.

Currently, studies devoted to establish the anatomical and histological patterns of the internal organs organization in animals depending on their species and breed, as well as conditions of detention are the most relevant. The liver morphology in representatives of the ruminant family has not been sufficiently studied. Questions regarding the micro- and ultra-structural organizations of the gallbladder wall remain open. The aim of the study was to establish the ultra-structural organization features of the gallbladder mucous membrane of an Anglo-Nubian goat. The material for the study was the gallbladder wall's fragments of an adult Anglo-Nubian goat. Further processing of the obtained samples was carried out to acquire histological preparations. Ultra-thin sections were photographed in a Jem-1011 electron microscope at magnifications of 2,500 - 3,000. It was found that the gallbladder mucous membrane of an Anglo-Nubian goat is formed by the epithelial layer and its own lamina. The epithelial layer is represented by a single-layer prismatic epithelium. The nuclei are light, with clear contours. The apical surface of epithelial cells forms microvilli and the cytoplasm of the apical pole of cells contains many electron-dense secretory granules. The lateral surfaces of the cells in their apical part are interconnected by tight contacts. The lamina propria is formed by loose connective tissue containing many blood vessels and nerve fibers. Referring to the scientific literature describing possible pathologies of the gallbladder, we can conclude that the picture presented in the results generally corresponds to the position of the gallbladder without pathologies.

Structural and organometric changes of the uterus in conditions of dark deprivation

The effect of 30-day dark deprivation (light-dark cycle 24/0 h, artificial illumination 300 Lux) and 14-day correction with melatonin on the endometrium of the uterus was studied in an experiment on mongrel females of 4 months of age. It was found that 30-day dark deprivation leads to hyperplastic processes of the endometrium: an increase in the number of uterine glands (by 18.9 % p 0.05), thickening of the endometrium (by 12.5 %, p 0.05). Morphometric characteristics of the endometrium: single-layer columnar epithelium of the endometrium and uterine glands were corrected by administration of exogenous melatonin for 14 days.

Amniotic membrane transplantation: structural and biological properties, tissue preparation, application and clinical indications.

The amniotic membrane is a single epithelial layer of the placenta. It has anti-inflammatory, anti-scarring, anti-angiogenic and possibly bactericidal properties. The basement membrane of the amniotic membrane acts as a substrate to encourage healing and re-epithelialisation. It has been used in many ocular surface diseases including persistent epithelial defects (corneal or conjunctival), chemical or thermal burns, limbal stem cell deficiency, cicatrising conjunctivitis, ocular graft versus host disease, microbial keratitis, corneal perforation, bullous keratopathy, dry eye disease, corneal haze following refractive surgery and cross-linking, band keratopathy, ocular surface neoplasia, pterygium surgery, and ligneous conjunctivitis. This review provides an up-to-date overview of amniotic membrane transplantation including the structural and biological properties, preparation and application, clinical indications, and commercially available products.

Shedding light on the black box of a neural network used to detect prostate cancer in whole slide images by occlusion-based explainability

Diagnostic histopathology faces increasing demands due to aging populations and expanding healthcare programs. Semi-automated diagnostic systems employing deep learning methods are one approach to alleviate this pressure. The learning models for histopathology are inherently complex and opaque from the user's perspective. Hence different methods have been developed to interpret their behavior. However, relatively limited attention has been devoted to the connection between interpretation methods and the knowledge of experienced pathologists. The main contribution of this paper is a method for comparing morphological patterns used by expert pathologists to detect cancer with the patterns identified as important for inference of learning models. Given the patch-based nature of processing large-scale histopathological imaging, we have been able to show statistically that the VGG16 model could utilize all the structures that are observable by the pathologist, given the patch size and scan resolution. The results show that the neural network approach to recognizing prostatic cancer is similar to that of a pathologist at medium optical resolution. The saliency maps identified several prevailing histomorphological features characterizing carcinoma, e.g., single-layered epithelium, small lumina, and hyperchromatic nuclei with halo. A convincing finding was the recognition of their mimickers in non-neoplastic tissue. The method can also identify differences, i.e., standard patterns not used by the learning models and new patterns not yet used by pathologists. Saliency maps provide added value for automated digital pathology to analyze and fine-tune deep learning systems and improve trust in computer-based decisions.

Metabolism and Microstructure of the Small Intestine Wall in Patients With Colorectal Cancer

RELEVANCE In patients with colorectal cancer (CRC), the normal small intestine, located outside the pathological focus, undergoes changes that may be the cause of digestive dysfunction after radical surgery to remove the tumor.The assessment of metabolic and microstructural changes in the ileum mucosa in patients with colorectal cancer is necessary to correct the algorithms of postoperative therapy and enteral nutrition. Modern means of optical bioimaging are potentially capable of solving this complex diagnostic problem.AIM OF STUDY To study the features of metabolism and morphological structure of the wall of a conditionally normal small intestine in the mucosa in patients with stage 1–3 CRC using macro- FLIM and optical coherence tomography (OCT).MATERIAL AND METHODS The object of the study was the wall of the ileum (66 samples) from the mucosal side of patients with histologically confirmed CRC stages 1–3 with tumor location in the right sections of the colon. Eight samples were obtained from patients with stage 1 CRC, 38 samples were obtained from patients with stage 2 and 20 samples were obtained from patients with stage 3 tumor. The volume of surgical intervention is right-sided hemicolectomy with total mesocolonectomy, CME (D2 lymph node dissection). Fresh tissue samples were examined using fluorescent lifetime macroimaging (macro-FLIM ) and OCT, followed by histological analysis of the material.RESULTS According to a histological study in the small intestine of patients with stage 1 CRC, the mucosa is covered with a normal single-layer prismatic border epithelium. In the intestine samples of patients with stage 2 CRC, mucus hypersecretion with areas of fibrosis and vascular congestion was observed. At the 3rd stage of CRC, the mucous membrane of the small intestine was loose, with local thickenings, areas of fibrosis with severe leukostasis, and foci of atrophy. None of the samples showed histological signs of a malignant tumor.According to OCT data, in the mucous membrane of the small intestine in patients with the 1st and 2nd stages of CRC, the contours of the villi and, partially, the crypts were well visualized. The structure of the villi was smooth, not coarse, and the shape was regular. In patients with stage 3 CRC, the contours of the crypts and villi were indistinct. There were no differences in the OCT picture between histologic preparations in the 1st and 2nd stages of CRC: the structure of the villi of the small intestine was clear, the shape was unchanged. According to FLIM data, statistically significant differences were revealed in the mean fluorescence lifetime values of reduced nicotinamide dinucleotide (phosphate) NAD(P)H (τm) between 2nd and 3rd (p=0.031), 1st and 3rd (p=0.018) by CRC stages. At the 1st stage of CRC τm was 1.61 [1.30; 2.02] ns, at the 2nd stage 1.50 [1.36; 1.73] ns, at the 3rd stage 1.37 [1.22; 1.51] ns. The FLIM results suggest an increase in the role of glycolysis in enterocyte energy metabolism along with progression of the CRC stage.CONCLUSION In patients with cancer of the right colon, lesions of the microstructure of the mucous membrane were revealed in the ileum not affected by the malignancy. At the same time, the severity of microstructural disorders in the wall of the small intestine is associated with the stage of tumor development in the colon. Bioimaging technologies, namely, methods of optical coherence tomography and fluorescence lifetime macroimaging, made it possible to objectively display microstructural and metabolic disorders in the ileum wall. The data of optical colorectal tomography demonstrated differences in the structural picture of the intestinal villi in patients with stages 1–2 and 3 of colorectal cancer. Results of fluorescence lifetime macroimaging of the metabolic cofactor nicotinamide dinucleotide (phosphate) confirmed an increase in the role of glycolysis in the energy metabolism of enterocytes along with an increase in the stage of colorectal cancer. The identified disorders in the state of the small intestine develop in patients with colorectal cancer before surgery and are highly likely to be an important pathogenetic link of malabsorption in the postoperative period. If the hypothesis is confirmed, the developed algorithm for the complex diagnosis of microstructural and metabolic disorders in tissues will expand the possibilities for the rehabilitation of patients with cancer of the right colon.

P-343 The role of Yes-Associated protein (YAP) activity in uterus adenogenesis process

Abstract Study question Could Yes-Associated protein(YAP) be effective in the adenogenesis process that occurs in the mouse uterus in the postnatal period? Summary answer It was observed that the YAP and phospho-YAP levels decreased in mice with inhibited gland development during adenogenesis process when compared to the control groups. What is known already The mouse uterus is composed of undifferentiated mesenchyme surrounded by a single layer of epithelium at birth. On the 5th Postnatal Day (PD), the luminal epithelium begins to bud, and the process called adenogenesis, which is termed as gland development in the uterus, begins. The gland development is evident on the PD 10th day. The uterus shows adult tissue characteristics by PD 15th-20th days. Although it has been stated that various signaling pathways are active in this process, Hippo signaling pathway role in the adenogenesis process have not been clarified yet. Study design, size, duration The uterus with normal gland development and gland development inhibited by Progesterone were evaluated for YAP and phospho-YAP, which is one of the main components of Hippo signaling pathway, by immunohistochemistry, western blotting, and q-RT-PCR methods. For experimental groups, 50 µg/g Progesterone was dissolved in 0.1 mL Sesame oil and for control groups, only 0.1 mL of Sesame oil given subcutaneously on PN 2nd-10th days. Animals were sacrificed on the PN 5th-10th and 15th days. Participants/materials, setting, methods In total of 30 newborn Balb/c female mice were used. They were divided as control (n = 15) and experimental(n = 15) groups. After the injections were finished, mice from both groups at PN5th(n = 5), PN10th(n = 5), and PN15th(n = 5) days were cervical dissociated, and uteri were collected. For immunohistochemical analyses, tissues were taken into buffered formalin, paraffin blocks were made, and the sections were taken. Protein and RNA isolations were performed from uteri for western blotting and q-RT-PCR analyses, respectively. Main results and the role of chance When YAP expression was evaluated by immunohistochemistry, western blotting and q-RT-PCR methods, there was no difference between the groups on the PN 5th day. But there was an active signaling was observed in the control groups on the PN10th day, which is very important for gland formation, and on the PN 15th day, that is effective in the maturation process. On the PN10th and 15th days, it was determined that YAP and phospho-YAP signal expression were decreased significantly in the experimental groups when compared with the control groups in immunohistochemically and protein levels. In addition, these findings were supported by mRNA analysis with YAP. Limitations, reasons for caution The study was performed in vivo mouse model. Further studies can be done with a transgenic animal model. Wider implications of the findings Considering the contribution of uterine gland development to the implantation process, errors in the development of these glands may cause infertility. This study can bring a new perspective to researching the uterus adenogenesis period and causes of infertility and treatment approaches. Trial registration number not applicable

Cartesian genetic programming for image analysis of the developing drosophila eye

Automatic feature extraction methods have gained increasing attention in modern image processing. The confocal images of the single-layered epithelium of the developing Drosophila eye may form an excellent model system to develop methods for complex feature extraction. The aim of this work was to explore Cartesian genetic programming for determination of the boundaries of ommatidia, the light-sensitive units in the presumptive eye region. Application of Cartesian genetic programming for the analysis of Fasciclin III expression has shown good results. This opens interesting perspectives for further use of this technology in the automatic analysis of confocal images.

Histological changes of the skin during postembryonic development of the crested newt Triturus ivanbureschi (Urodela, Salamandridae)

BackgroundAmphibian skin has been studied for many decades, especially the metamorphic changes in the skin of frogs. Less attention has been paid to salamander skin. Here, we describe changes in the skin structure during postembryonic development in a salamandrid species, the Balkan crested newt Triturus ivanbureschi. MethodUsing traditional histological techniques we examined the skin in the trunk region of three premetamorphic larval stages (hatchling, mid larval and late larval) and two postmetamorphic stages (juvenile, just after metamorphosis, and adult). ResultsIn larval stages, skin consists only of the epidermis, which gradually develops from the single epithelial cell layer in hatchlings, to a stratified epidermis with gland nests and characteristic Leydig cells at the late larval stage. During metamorphosis, Leydig cells disappear, and the dermal layer develops. In postmetamorphic stages, skin is differentiated on stratified epidermis and the dermis with well-developed glands. Three types of glands were observed in the skin of the postmetamorphic stages: mucous, granular and mixed. Gland composition appears to be stage- and sex-specific, with juveniles and adult female being more similar to each other. In juveniles and adult female, there are a similar proportion of glands in both dorsal and ventral skin, whereas in adult male granular glands dominated the dorsal skin, while mixed glands dominated the ventral skin. ConclusionOur results provide a baseline for future comparative research of skin anatomy in salamanders.

Pathological changes in traumatization of the upper jaw under the conditions of sinus lifting simulation in rats

Background. Simulation of surgical interventions in the maxillofacial region provokes a number of physiological reactive changes in the body of experimental animals. Thus, it was revealed that there are changes in the balance of the autonomic nervous system, activation of the hypothalamic-pituitary-adrenal and adrenergic systems, changes in behavioral reactions, as well as the occurrence of anxiety state. At the same time, the morphological causes of such reactions are not fully understood. Aims. The study provides data on morphological changes in the area of experimental trauma of the upper jaw during modeling of sinus lifting, dental implantation in rats. Materials and Methods. The study used male rats of the Wistar line weighing 210-280 g. Surgical interventions in all groups were performed under general anesthesia with the introduction of a solution of Zoletil 100 into the tail vein. In the first group, septoplasty (n=10) was simulated by the standard method by zigzag scarification of the nasal mucosa according to the standard method. In the second group (n=10), dental implantation with a titanium implant was performed after the hole was formed using a drill. In the third group (n=10), only a hole was made in the alveolar process of the upper jaw without subsequent manipulations. This group was a comparison group for groups with dental surgical interventions. In the fourth group, 10 rats underwent sinus lifting with bone chips with simultaneous implantation of a titanium implant. In the fifth group (n=10), with the help of a microdrill through a pre–formed hole in the alveolar process of the upper jaw, maxillary sinus was performed with damage to the mucous membrane of the ipsilateral maxillary sinus. Results. First group. On day 2, there was focal desquamation of a single-layer multi-row ciliated epithelium with local defects up to the basement membrane, multiple hemorrhages (extensive, with the presence of blood clots) in the mucosal lamina proper, mucosal edema (common), moderate diffuse infiltration (polymorphocellular). On the 4th day, signs of acute exudative serous inflammation were revealed. Second group. On the 2nd day, the wound surface contained cellular detritus, leukocytes, blood clots and a scab that did not adhere to the wound surface. (Fig. 2). On the 4th day, the signs of inflammation were not significant, macrophages, fibroblasts and lymphocytes predominated at the site of injury. On the 6th day, the formation of a clear demarcation line in the area of damage was noted with the formation of a shaft containing leukocytes and fibroblasts. Third group. On the 2nd and 4th days, the condition of the damaged tissues was characterized by the formation of scabs consisting of cellular detritus, necrotized tissue, leukocytes, erythrocytes (Fig. 4). On the 6th day, an accumulation of fibroblast-like cells, macrophages, and the formation of fibers of newly formed connective tissue was observed in the area of damage. Fourth group. On the 2nd and 4th days, extensive hemorrhages, the formation of scabs consisting of cellular detritus, necrotized tissue, leukocytes, erythrocytes were noted in this group. Fifth group. On the 2nd and 4th days, multiple hemorrhages with the presence of exudate blood clots were observed in the area of injury. Cellular detritus and necrotic tissue were present. Mucosal edema was widespread with extensive polymorphocellular infiltration. Conclusion. Different surgical interventions lead to different morphological changes, which probably affects the severity of physiological reactions under surgical stress.

MICRO- AND ULTRAMICROSCOPIC STRUCTURE OF THE LEFT ATRIA-VENTRICULAR VALVULAR APPARATUS IN HUMAN AT THE MATURE AGE IN NORM

This article presents the morphological characteristics of the mitral valve of a normal heart of an adult at a mature age.The purpose of our investigation is to find out the peculiarities of the morphology of the structural components of the mitral valve apparatus of the heart of a person of mature age in the norm.Material and methods. The study was performed on 32 preparations of mitral valves of adult human hearts. A complex of morphological research methods was used: methods of light and electron microscopy, histochemical method.Results. With the use of a complex of morphological research methods, a study of the structural components of the mitral valve apparatus of a normal mature person was carried out and their histoarchitectonics was established at the micro- and sub-microscopic levels.Conclusions. The leaflets of the mitral valve are connective tissue plates covered with a single-layer flat epithelium - endothelium. The leaflets are formed by fibrous connective tissue of different density, as a result of which three layers are identified: spongy, fibrous and ventricular. Typical chordae tendineae in the form of connective tissue threads extend from the papillary muscles to the leaflets of the mitral valve and attach to their ventricular surface. The skeleton of chordae tendinea is formed by dense fibrous connective tissue. Striated cardiac muscle tissue is found in some chordae tendinea in the areas on the side of the papillary muscles. The papillary muscles are formed by the working fibers of cardiomyocytes, which form a kind of network due to branches and anastomoses. The working fibers of cardiomyocytes are accompanied by layers of loose fibrous connective tissue, which includes a large number of blood vessels.

MORPHOLOGICAL AND HISTOLOGICAL CHARACTERISTICS OF THE ENDOMETRIUM OF THE UTERUS OF COWS WITH CATARRHAL ENDOMETRITIS

The article presents the results of the study of the pathomorphological state of the endometrium in cows with catarrhal endometritis in Kostanay region. Based on studies of tissues of reproductive organs in cows at the age of 4 to 7 years were used.with catarrhal endometritis, it was found that in the structural organization of the endometrium in cows, dystrophic processes of the of the integumentary epithelium, glandular pits with vacuolization and pyknosis of their nuclei were observed. The terminal sections of the alveolar glands of the endometrial mucosa are lined with a single-layer double-row epithelium. In the epithelium, there are simultaneously high prismatic secretory cells, enlarged in volume due to secret granules, and large, rounded cells with a large volume of light cytoplasm and a round nucleus located in the center of the cell. The mucous membrane of the uterus with catarrhal endometritis is hyperemic, during histoexamination, infiltration of the mucous membrane by plasma cells, emigration of leukocytes was noted. Polypous thickening of the uterine mucosa is detected.