The Role of Hypoxia in the Development of Some Pathological Conditions and Malignant Tumors

Bogdanova, N.O.; Pogorela, N.H.; Lukyanetz, E. A.

doi:10.15407/fz67.02.053

Cited by 3 publications

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References 46 publications

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“…Зазначимо, що зміни електричної активності міокарда виявляють також в осіб з ізольованим залізодефіцитом. ЗД супроводжується синдромом порушення збалансованої активності ВНС, частота виникнення та інтенсивність якого залежать від ступеня ЗД [12,13,14,15]. У результаті дослідження Emre Yilmaz [16] встановлено: низький рівень заліза може підвищувати аритмогенну чутливість міокарда через збільшення наявності фрагментованих QRS, інтервалу T peak -T end (Тр-е), співвідношення Tp-e/QT і Tp-e/QTc.…”

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The peculiarities of changes in myocardial electrical activity and heart rate variability in patients with coronary artery disease depending on the stage of concomitant iron deficiency

Konovalova,

Mikhailovska

2023

Zaporozhye Medical Journal

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The aim of the study: to assess changes in myocardial electrical activity and heart rate variability (HRV) in patients with coronary artery disease (CAD) depending on the stage of iron deficiency (ID) and identify their relationship with ferrokinetic parameters. Materials and methods. In total, 90 patients with CAD, stable angina II–III FC were examined (men – 35, women – 55, age – 69 (61; 72) years). The patients were divided into 4 groups: the 1st group (n = 16) consisted of patients with concomitant ID anemia (IDA) of mild and moderate severity, the 2nd (n = 15) – with latent ID, the 3rd (n = 14) – with functional ID, the 4th (n = 45) – patients with CAD without iron metabolism disorders. The HRV features during 24 hours, daytime and nighttime as well as their relationships with ferrokinetic and hematological parameters were analyzed. The data analysis was performed using Statistica 13.0. Results. CAD patients with concomitant IDA demonstrated a tendency to have a higher average daytime heart rate value (U = 14.0; p ≈ 0.08), a longer duration of tachycardia (U = 20.0; p ≈ 0.06), and a significantly greater number (2.4 times) of ventricular extrasystoles (VE) (U = 7.0; p < 0.05) compared to patients without iron metabolism disorders. There were no statistically significant differences in heart rate, episodes of tachycardia, and the number of arrhythmic events in CAD patients with different stages of ID. During the temporal analysis of HRV indicators, patients with different stages of concomitant ID demonstrated a decrease in overall HRV due to SDNN-index, rMSSD (%) and HRVT triangular index both in active and passive periods as compared to patients without iron metabolism disorders. Spectral analysis of HRV has revealed reduced parasympathetic activity of the autonomic nervous system due to HF indicator in patients of the 1st–3rd groups. The presence of concomitant IDA was characterized by maximum changes in HRV indicators and the predominance of central mechanisms of HRV regulation over autonomic ones, which was confirmed by a significant increase in the centralization index (IC) and stress index (SI). For CAD patients with concomitant IDA and latent ID, a number of relationships between ferrokinetic and HRV parameters was found. There were no statistically significant correlations between indicators of iron metabolism and HRV in patients with CAD and functional ID. Conclusions. The decrease in iron stores in the body due to its tissue and transport reserves is accompanied by changes in the myocardial electrical activity, a progressive reduction in heart rate variability, autonomic dysfunction towards a suppression of the parasympathetic domain activity, confirming the relevant correlations with the ferrokinetic parameters.

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Section: Discussionunclassified

The peculiarities of changes in myocardial electrical activity and heart rate variability in patients with coronary artery disease depending on the stage of concomitant iron deficiency

Konovalova,

Mikhailovska

2023

Zaporozhye Medical Journal

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Development of Ultrastructural Changes in Diaphragm Muscle Fibers During Partial Tracheal Stenosis in Young Sexually Immature Rats

Molochek,

Savosko,

Makarenko

2024

Act. Probl. of the Modern Med.

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Introduction. The study of congenital pathology of the respiratory tract in children is of great importance for theoretical and clinical pediatric otolaryngology. Currently, in the scientific literature there are single works concerning the study of the pathogenesis and clinic of laryngomalacia. First of all, this concerns the effect of acute and chronic hypoxia on the muscles of the respiratory system, in particular, the diaphragm. The aim of thіs work is to reveal the effect of hypoxia on the development of pronounced structural and functional changes in the diaphragm muscles of sexually immature animals when modeling partial tracheal occlusion. Materials and methods. Surgical partial occlusion of the trachea was performed on in sexually immature Wistar rats; we applied electron microscopy, morphometric and statistical research methods. Results. The obtained data demonstrated that the muscle fibers of the diaphragm are characterized by significant structural, functional and metabolic resistance to the development of acute or chronic hypoxia due to limited lung ventilation in rats. The density of muscle fibers did not change in any of the used terms of the experiment (7 and 21 days). On the 7th day of hypoxic exposure, a change in the state of the matrix of mitochondria of muscle fibers was observed, which was accompanied by partial ultrastructural rearrangements of the organization of these organelles. At the same time, no significant changes were observed during histological studies. Electrongrams demonstrated the ultrastructural damages were mainly limited to focal reduction of myofibrils and an increase in the mitochondria's diameter and found as especially pronounced on day 21 (a state of chronic hypoxia) on the muscular component of the respiratory system in rats. These changes are accompanied by the development of dystrophic disorders in the diaphragm myofibrils. On day 21 changes in the transendothelial transport of substance molecules were also detected. This was based on establishing the fact of a significant reduction in the number of pinocytosis vesicles in the cytoplasm of endothelial cells of diaphragm hemocapillaries in animals with partial tracheal occlusion. Disruption of the structural organization of actomyosin complexes was revealed in muscle fibers due to pathological changes in the mitochondria of myofibrils. It should be noted the development of destruction or complete loss of an important ultrastructural component of muscle fibers, Z-lines. These changes were completely absent on the 7th day following the influence of partial tracheal occlusion and the development of acute hypoxia. Moreover, on day 21, partial lysis of a significant amount of myofilaments of muscle fibers was observed. In addition, the development of the process of fiber swelling was detected against the background of which the above-mentioned ultrastructural destruction of the muscular component in the diaphragm was observed. These changes indicate the need for earlier treatment of laryngomalacia in children. The delay in surgical intervention leads to the development of severe or irreversible structural changes not only in the respiratory organs, but also in their muscular system. Conclusion. The muscular elements of the diaphragm have the pronounced and significant resistance to the state of hypoxia under conditions of limited ventilation of the respiratory tract. Ultrastructural and morphometric data, found on the 21st day after the modeling of partial tracheal stenosis, are not only of a compensatory and adaptive in nature, but also signs of pronounced disorders in the muscle fibers of the central part of the diaphragm in test animals.

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Sex features of the development of oxidative stress in high and low hypoxic resistancy rats, which experienced repeated stressful episodes of immobilization

Denefil,

Miroshnyk,

Venher

et al. 2024

Polski Merkuriusz Lekarski

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Aim: of the study was to find out the sexual characteristics of the development of oxidative stress in rats with high and low resistance to hypoxic hypoxia (HRH, LRH) during repeated stressful episodes of immobilization. Materials and Methods: The study was performed on 96 white HRH, LRH male and female Wistar rats. The animals were divided into eight groups: 1 – control (HRH, LRH) males and females, 2 – immobilization (HRH, LRH) males and females. Immobilization stress was induced by gently restraining the animals four Times by all paws and maxillary central incisors dorsally for 1 hour at an interval of 72 hours. The concentration of diene and triene conjugates (DC, TC), Schiff’s bases (SB), TBA-active products (TBA-ap), activity of superoxide dismutase (SOD) and catalase (CAT), reduced glutathione (GSH), activity of glutathione peroxidase (GP) and glutathione reductase (GR) were determined in the homogenate of heart. A morphological study of heart preparations stained with hematoxilin and eosin was carried out. All studies were performed in control, after 24 hours after last immobilization. Results: In control HRH, compared to LRH males, the values of TBA-ap were found to be lower. Under stress, an increase of LPO was noted in HRH and LRH males, only SB decreased. Higher level of LPO products noted in LRH rats compared to HRH. In control HRH females, compared to LRH, the content of DC, SB were higher and TBA-ap – lower. In HRH females, compared to HRH males, TC was higher and SB – lower. Under stress, in HRH females DC and TBA-ap were increased, TC and Sb – decreased. In LRH females all indicators increased. Lower TC and TBA-ap values were noted in HRH compared to LRH females rats. In control HRH males, compared to females, lower TC and higher values of SB were found. In LRH males, compared to females, the values of DC, TC, SB were higher. During stress, a more intensive course of LPO was noted in males. SOD in control HRH males, compared to LRH, was higher; CAT was not statistically different. Under stress, SOD decreased, CAT – increased. In HRH males, compared to LRH, in this group SOD was higher CAT – lower. In the control, HRH females, compared to LRH, had higher SOD, lower – CAT. Under stress, CAT increased in HRH females; in LRH females CAT decreased and SOD – increased. In HRH females, compared to LRH, CAT was higher. In control males, compared to females, SOD and CAT was higher. Under stress higher SOD was in females, and CAT – in males. GSH and GP were higher in control HRH compared to LRH males and females. Under stress, in males the GSH increased, GR decreased; GP in HRH decreased, in LRH it increased. HRH males, compared to LRH, GSH and GR were higher, GP – lower. Under stress, in females GSH, GP, GR in females decreased; HRH, compared to LRH, had higher GP and GH. In intact HRH males, compared to females, was higher GR and less GP; in LRH males, compared to females, GR was higher. Under stress, males had higher GSH, GP and GR values compared to females. The studied biochemical changes in the heart are accompanied by alterative changes in the structural components of the myocardium in the experimental groups. Conclusions: Congenital resistance to hypoxia is associated with a greater power of the enzymatic and non-enzymatic links of the antioxidant system. Immobilization stress repeated four times with an interval of 72 hours is accompanied by the most significant increase in the content of lipid peroxidation products in the heart homogenate of lower resistant to hypoxia rats, especially males. A decrease in Schiff bases is observed in all males and highly hypoxia-resistant females. In males, a more intense accumulation of lipid peroxide oxidation products, higher catalase activity and a more active glutathione system were noted. Females have significantly higher superoxide dismutase activity. Morphological changes confirm more damage to the heart of low hypoxia-resistant rats, more males. KEY WORDS : heart, sex, rats, resistancy to hypoxia, biochemical changes, morphological changes, oxidative stress, lipid peroxidation, antioxydants

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The Role of Hypoxia in the Development of Some Pathological Conditions and Malignant Tumors

Cited by 3 publications

References 46 publications

The peculiarities of changes in myocardial electrical activity and heart rate variability in patients with coronary artery disease depending on the stage of concomitant iron deficiency

The peculiarities of changes in myocardial electrical activity and heart rate variability in patients with coronary artery disease depending on the stage of concomitant iron deficiency

Development of Ultrastructural Changes in Diaphragm Muscle Fibers During Partial Tracheal Stenosis in Young Sexually Immature Rats

Sex features of the development of oxidative stress in high and low hypoxic resistancy rats, which experienced repeated stressful episodes of immobilization

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