Development of thyroid pathology in medical workers with chronic exposure to low doses of ionizing radiation

Introduction. The literature review deals with the effects of ionizing radiation and radiation on the body of medical personnel.Materials and methods. 50 actual sources were analyzed. The relevance of the study of the constant, long-term influence of low doses of radiation is shown, in view of the increasing use of sources of ionizing radiation in various fields of scientific and practical human activity, including medicine.Results. Thanks to the analysis of numerous literature data, it was revealed that operating doctors, who are faced in their work with sources of ionizing radiation, often do not have a sufficient level of protection of the thyroid tissue from radiation. It was revealed that the overwhelming majority of studies highlighting thyroid pathology in medical personnel working with X-rays are aimed at identifying the risks of thyroid cancer and does not take into account the pathology of non-tumor genesis. Analyzed the data of scientific publications, allowing to draw a conclusion about the effects of chronic exposure to ionizing radiation, namely X-rays, in low doses on the thyroid tissue from a morphological and functional point of view.Discussion. It was established on the basis of the analysis of experimental data that under the influence of low-dose X-ray radiation, the intercellular contacts of thyrocytes are disconnected, which can lead to a decrease in the synthesis of thyroid hormones and, as a consequence, to the development of hypothyroidism.Conclusion. Based on the analysis of the experimental data, it has been established that under the influence of low-dose X-rays there is a disconnection of intercellular contacts of thyrocytes, which may lead to a decrease in the synthesis of thyroid hormones and, consequently, to the development of hypothyroidism.

Supposition about absence of contact inhibition of cancer cells

As is known, the superficial charge of most somatic cells is negative. Proceeding from this fact, somatic cells never interact. There is always some type of space (intercellular space) between them. Intercellular contacts are predominantly determined by two main factors: Van der Waals (positive taxis) and electrostatic (negative taxis) forces contributing to the formation of membrane electric potential. Presence of the intercellular space is a structural representation of the balance bet­ween these forces (contact inhibition).

Ultrastructural changes in the microvessels and perivascular space in cerebral infarction in the experiment

Background. Ischemic stroke is the second most common cause of death after coronary heart disease and the most common cause of disability worldwide. Much of the recent basic research on stroke is concerned with the mechanisms underlying the dysfunction and adaptation of the neurovascular block, which includes the blood-brain barrier structures, microglia, neurons, and the extracellular matrix of the basement membrane. Isolated studies of recent years have been devoted to the issues of morphology and in particular the ultrastructure of the brain in ischemic injury. Meanwhile, only morphological studies can reveal the peculiarities of the response of cellular structures to the influence of various adverse factors. Objective – to investigate ultrastructural changes in the vessels of the brain and perivascular space in experimental ischemic heart attack. Methods. Experimental cerebral infarction was reproduced on 15 white Wistar rats by injection of a suspension of barium sulfate in sterile saline in a ratio of 1: 3 in the amount of 0.1 -0.3 ml. Three animals formed a control group. The material was collected in terms of: up to 3, 9, 12 days and more than 12 days from the beginning of the experimental action, followed by standard processing of the material for electron microscopy. Results. In the early stages of ischemic brain damage perivascular edema, destructive changes of capillaries with destruction of basement membranes are registered. Some microvessels undergo irreversible changes with deformation of the vascular lumen, pyknosis and lysis of endothelial nuclei, destruction and vacuolation of cytoplasmic structures, microvacuolation and edema of mitochondria with partial destruction of cristae and enlightenment of the mitochondrial matrix. In the endothelium with signs of coagulation processes in the cytoplasm and nucleus, changes in cell contacts were observed. Structural changes of vessels are combined with changes of perivascular processes of astrocytes. On days 9 and 12, the structure of the endothelium, perivascular astrocytes, and intercellular contacts are restored. Hyperplasia of intracytoplasmic structures, increase in mitochondria and length of cytoplasmic network are noted. In the cells of the perivascular environment and in the cytoplasm of pericytes a significant number of phagolysosomes is detected, in the long term in the perifocal areas of irreversible ischemic changes around the vessels is reparative astrogliosis. Conclusion. Ultrastructural changes of the microcirculatory part in the perifocal areas of ischemic lesions within 3 days are characterized by perivascular edema and destructive changes in the endothelium of capillaries and pericytes, damage to basement membranes, changes in cell contacts. After 9-12 days in the endothelium, the processes of intracellular regeneration increase, the ultrastructure of intercellular contacts is restored. A significant number of phagolysosomes is registered in the cells of the perivascular environment and in the cytoplasm of pericytes, and reparative astrogliosis is detected in the perifocal areas of irreversible ischemic changes around the vessels.

Morphological manifestations of irritable bowel syndrome

The article presents modern data on morphological changes in the intestinal mucosa in patients with irritable bowel syndrome. There were analyzed the studies of different years on the morphological manifestations of irritable bowel syndrome. It has been shown that this pathology has an unusual low-grade inflammation. Mast cells play an important role in these inflammatory disorders, they have an effect on motility disorders, visceral hypersensitivity and other pathogenetic factors of irritable bowel syndrome. Disorders of intercellular tight junctions in this category of patients were also analyzed. The role of proteins involved in intercellular contacts (occludin, claudin, ZO) has been characterized. An analysis of the studies investigating these disorders has been carried out. The article provides examples of the analysis of biopsies in patients with irritable bowel syndrome using various methods of their assessment.

Disentangling cadherin-mediated cell-cell interactions in collective cancer cell migration

Cell dispersion from a confined area is fundamental in a number of biological processes, including cancer metastasis. To date, a quantitative understanding of the interplay of single cell motility, cell proliferation, and intercellular contacts remains elusive. In particular, the role of E- and N-Cadherin junctions, central components of intercellular contacts, is still controversial. Combining theoretical modeling with in vitro observations, we investigate the collective spreading behavior of colonies of human cancer cells (T24). Inhibition of E- and N-Cadherin junctions decreases colony spreading and average spreading velocities, without affecting the strength of correlations in spreading velocities of neighboring cells. Based on a biophysical simulation model for cell migration, we show that the behavioral changes upon disruption of these junctions can be explained by reduced repulsive excluded volume interactions between cells. This suggests that cadherin-based intercellular contacts sharpen cell boundaries leading to repulsive rather than cohesive interactions between cells, thereby promoting efficient cell spreading during collective migration.

The role of exosomal tetraspanins and proteases in tumor progression

Major (CD9, CD63, CD81) and others (CD82, CD151, Tspan8) tetraspanins are widely represented in exosomes, where they interact with various proteins and form functional tetraspanin complexes. Tetraspanin complexes include proteases. Tetraspanin-associated exosomal proteases (ADAM proteases, MMPs, EMMPRIN) play an important role in the processes of cell motility, migration, invasion and formation of metastases. Also, a significant contribution to tumor progression is made by proteases that are not associated with tetraspanins. They destabilize intercellular contacts, promote migration and invasion of tumor cells, participate in the regulation of the expression IGF-I, VEGF and transcription factors activation/deactivation. The role of other proteases of exosomes in the processes of tumor progression is being clarified.