Features of Appendix and the Characteristics of Appendicitis Development in Children with COVID-19

BACKGROUND

Research on the subject of the influence of SARS-CoV-2 mechanisms on human homeostasis remains an actual problem. Particular interest is the study of pathomorphological changes in the appendix in children with COVID-19.

OBJECTIVES

Aim of this study: morphological and molecular biological evaluation of the appendix in children of different age groups with COVID-19.

METHODS

Groups were formed on the basis of anamnestic, clinical, and morphological data: I (n = 42; aged 2 to 18 years, average age-10.8 ± 4.79)-with an established clinical diagnosis: coronavirus infection (COVID-19; PCR+); II (n = 55; aged 2 to 18 years, average age-9.7 ± 4.77)-with a confirmed clinical diagnosis of acute appendicitis; collected before the onset of the COVID-19 pandemic in 2017-2019; and III (n = 38; aged 2 to 18 years, average age-10.3 ± 4.62)-the control group. Histological and immunohistochemical studies were conducted using primary antibodies to CD3, CD4, CD68, CD163, CD20, and CD138 and to pro-inflammatory (IL-1, IL-6) and anti-inflammatory (IL-4, IL-10) cytokines.

RESULTS

In most samples of appendixes in children with COVID-19, signs of destructive phlegmonous-ulcerative and gangrenous appendicitis were discovered. An increase in CD3+, CD4+, CD68+, CD163+, and CD20+ CD138+ immunocompetent cells was found in the appendix of children with COVID-19. As well, there was an increase in pro-inflammatory (IL-1, IL-6) and anti-inflammatory (IL-4, IL-10) cytokines.

CONCLUSIONS

The aforementioned pathological and immunohistochemical changes were more pronounced in the group of children aged 6-12 years (childhood).

Assessment of Proliferation and Apoptosis in Testes of Rats after Experimental Localized Electron Irradiation

BACKGROUND AND PURPOSE

With the emergence of linear accelerators in radiotherapy, it becomes necessary to accurately select new dosing regimens. The purpose of this study was to assess the morphological changes of spermatogenesis after radiation exposure.

MATERIALS AND METHODS

Male Wistar rats (n = 40) were subjected to targeted ionizing radiation on a pulsed electron accelerator "NOVAC-11" with doses of 2, 8 and 12 Gy. Spermatogenesis was assessed a week later using light microscopy and immunohistochemical method (antibodies to Ki-67, Bcl-2, p53, Caspase 3).

RESULTS

A decrease in the number of normal germ cells was seen in all experimental groups, while radioresistant Sertoli and Leydig cells were barely affected. The most serious damage to the tubules and germ cells was observed in 8 and 12 Gy irradiation groups. IHC analysis of testes after irradiation showed a shift in the proliferative-apoptotic balance toward apoptosis of germ cells: a decrease in the expression levels of Ki-67 and Bcl-2, an increase in p53-positive and caspase 3-positive cells by the end of the experiment.

CONCLUSION

Dose-dependent progressive pathomorphological changes in histoarchitectonics of the testes are traced, and a decrease in the number of germ cells is seen on the seventh day after irradiation with a pulsed electron accelerator "NOVAC-11".

Angiotensin-Converting Enzyme 2 and Furin Expression in the Appendix of Children with COVID-19

Background: The sudden outbreak of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has resulted in more than 261 million infections and an estimated 5.1 million deaths. Some vital organs such as the kidneys, heart, intestines, and lungs could be damaged by SARS-CoV-2. Questions remain regarding the effect of SARS-CoV-2 on the mucous membrane of the appendix in children. The aim of this study was to evaluate the knowledge of cytologic processes in appendix tissue in children with coronavirus disease 2019 (COVID-19). Patients and Methods: Fragments of the appendices of children with confirmed COVID-19 (n = 42) were studied by real-time polymerase chain reaction (PCR) to determine the expression of SARS-CoV-2 RNA and genes encoding protein complexes: ACE-2 and Furin. Results: We found traces of coronavirus genetic material in the appendices of children with COVID-19. We also found increased expression of ACE-2 and Furin in the tissue, which indicates favorable conditions for coronavirus infection. Conclusions: Viral load in the appendices of children can be reported based on the results of real-time PCR for SARS-CoV-2 and the expression of ACE-2 and Furin.