Extreme Medicine

ISSN Print 2713-2757 ISSN Online 2713-2765

Extreme Medicine

SCIENTIFIC AND PRACTICAL REVIEWED JOURNAL OF FMBA OF RUSSIA

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Nechaykina OV, Laptev DS, Bobkov DV, Petunov SG, Radilov AS

Synthetic short-acting opioids are commonly used in anesthesiology as painkillers because their effect is more pronounced compared to that of natural substances. However, they have a number of side effects that, when fentanyl is used in doses larger than therapeutic, can lead to a lethal outcome. This study aimed to assess the cardiotropic effects of high doses of fentanyl using a rat heart isolated in a Langendorff perfusion system. Parameters of the heart's contractile activity were recorded with the help of PowerLab Data acquisition system 8/30 (ADInstruments, USA) and processed in the LabChartProUpgrade 7.0 program. At the concentration of 3.7 × 10–6 M, which corresponds to the opioid content in blood after administration of a 5 ED50 dose, fentanyl caused the QT interval duration to grow by 22%, as registered on an ECG, and a 256% spike of T wave (compared to control; p < 0.05). At the concentration of 7.4 × 10–6 M (10 ED50), the drug decreased heart rate by 20.4% (p < 0.05) and triggered a coronary constrictor effect that raised the perfusion pressure by 18.6% (p < 0.05). Further increase of fentanyl concentration to 1.5 × 10–5 M (20 ED50) was accompanied by an 83.5% growth of the end diastolic pressure (p < 0.05). Administration of nalmefene, nonselective opioid receptor blocker, did not cancel the cardiovasotropic action of fentanyl. Thus, fentanyl has a dose-dependent cardiotoxic effect. Despite the drop in the registered values of isolated heart's parameters, the results of this experiment confirm that cardiac activity persists under the influence of high doses of the opioid.

Received: 2024-03-06

Published online: 2024-06-26

DOI: 10.47183/mes.2024.021

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VIEWS 26

Popova OV, Rusanov VB, Orlov OI

Today, the prospect of long-term interplanetary missions becomes relevant, that is why it is necessary to understand the changes in the cardiovascular system (CVS) that would occur in hypomagnetic environment. The study was aimed to assess the changes in the CVS mechanisms underlying formation of heart rate variability and bioelectric processes in the myocardium under conditions the 350-, 650-, and 1000-fold reduced Earth’s magnetic field. The experiment (2023) involved 6 male volunteers aged 26–37 years, in whom electrocardiography was continuously performed throughout 32 h. The data obtained were assessed by cluster analysis and analysis of variance. It was found than male volunteers, who belonged to the group showing predominance of parasympathetic effects, had enough functional reserve for critical values (exposure to the up to 1000-fold reduced magnetic field). In volunteers showing predominance of sympathetic modulatory effects, the adaptive response maintenance was ensured by the metabolic regulatory circuit. In this group, the response to the reduced magnetic field exposure was quite pronounced at the threshold of its 350-fold reduction. Our pilot experiment reflecting the effect of the reduced Earth’s magnetic field on the CVS is crucial for development of the concept of further experimental exposures related to magnetic field reduction benefiting space physiology and medicine.

Received: 2024-05-22

Published online: 2024-06-21

DOI: 10.47183/mes.2024.019

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VIEWS 83

Akhmadullina YuR, Vozilova AV, Krivoshchapova YaV

The understanding of the exposure effects on the human health could be improved by analyzing the influence of the chronic low dose rate exposure on the senescence of the immune system cells. It will also help to develop the measures aimed at the mitigation of the adverse effects. The objective of the study is to investigate the influence of the chronic low dose rate exposure on the senescence of the immune system cells using the cytogenetic markers. In the course of the research the authors evaluated the cellular senescence markers — genome instability and telomere depletion — in T-lymphocytes of the individuals exposed in the Southern Urals (exposure doses were 0.001 Gy — 4.7 Gy, the age of examined people was 40–89 years). The data analysis has demonstrated that the effect of chronic exposure on the T-cell senescence was indirect. Unstable chromosome aberrations occurred statistically significantly more frequently in exposed people aged 40–59 years (p = 0.012). Frequency of lymphocytes with micronuclei in exposed individuals differed in men and women (p = 0.001). Statistically significant decrease in the telomere length was revealed (for the chromosome arms 1q, 3p, 3q, 20p, 20q, 13q, 15p, 22q (p < 0.05); 19p, 21q (p < 0.01)).

Received: 2024-04-02

Published online: 2024-06-19

DOI: 10.47183/mes.2024.018

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VIEWS 52

Latartsev KV, Demina PN, Yashina VA, Kaspranskiy RR

During a space flight, cosmonauts have to adapt to new unique environmental conditions. As a result, they accumulate changes to their bodily systems that can eventually cause undesirable consequences potentially detrimental to the success of the mission. The review examines research papers investigating functional and structural changes occurring in the brain in the context of a spaceflight. Microgravity is believed to be the main factor behind the said changes: it causes redistribution of fluid in the body and conditions adaptive neural rearrangements at the microstructural level. Other elements peculiar to a spaceflight that can have this or that effect on the brain are also considered. In addition, this review scopes publications that allow assumptions about the specific causes of the registered morphofunctional alterations in the brain of cosmonauts.

Received: 2024-01-19

Published online: 2024-06-03

DOI: 10.47183/mes.2024.008

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VIEWS 106

Kolomiitsev VG, Gornov SV, Gornov VV, Burova IV, Eselevich RV, Litvinenko EA, Krupa RA, Karpenko DV

Retrocerebellar cysts of the brain represent the aspect that is important for determination of fitness for flight. The study was aimed to assess their impact on the pilot performance by conducting comparative analysis of MRI data of the first-year cadets and experienced pilots. We assessed the prevalence of retrocerebellar cysts among cadets and pilots, conducted non-contrast brain MRI, and compared the major academic and physical performance indicators, along with the results of professional psychological screen. The prevalence of retrocerebellar cysts among first-year cadets was 8.2%. High prevalence of asymptomatic retrocerebellar cysts among experienced pilots was revealed (two cases out of five). The intergroup comparison of indicators makes it possible to draw a conclusion about probable minor impact of such changes on fitness for flight. Further research is required to clarify the mechanisms underlying the impact of retrocerebellar cysts on the pilot performance and develop appropriate guidelines for medical boards.

Received: 2024-02-05

Published online: 2024-03-31

DOI: 10.47183/mes.2024.017

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VIEWS 263

Tolstoguzov SN, Fisher TA, Naida YuV, Lepunova ON

The study was focused on the features of spectral characteristics of the EEG alpha and theta ranges in the military academy cadets undergoing specific training to improve cold resistance (cold exposure training). The study was aimed to assess the impact of the military academy cadets’ incremental exposure to the graduated cold stress (cold exposure training) on spectral characteristics of the EEG alpha and theta rhythms. Students of the civil higher educational institution and military academy cadets were assessed (58 individuals in total). Cadets underwent a specific program focused on improving cold resistance (cold exposure training). Background EEG in the alpha and theta frequency ranges was recorded. Statistical data processing involved nonparametric comparison using the Mann–Whitney U test. The results were obtained suggesting that there were significant differences in spectral characteristics of alpha and theta rhythms between the group of foreign cadets and the controls. The cold exposure training program was effective in the group of Russian cadets, which had an effect on the cerebral homeostasis stability with some degree of instability of neurodynamic processes in the CNS. In foreign cadets, regular cold exposure training resulted in the pronounced disintegration of cortical-subcortical and intracortical interactions, as well as in the formation of binary alpha-theta structure of background EEG.

Received: 2024-02-20

Published online: 2024-03-31

DOI: 10.47183/mes.2024.016

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VIEWS 262

Katunina EA, Gryaznev RA, Shipilova NN, Katunin DA, Malykhina EA

The review is focused on essential tremor (ET), the most common extrapyramidal system disorder. Current understanding of the disease pathogenesis is provided; issues of classification and differential diagnosis are discussed. Modern ET treatment methods include therapeutic approaches and surgical interventions. The benefits of the new ET treatment method, the magnetic resonance-guided focused ultrasound treatment (MRgFUS), are described; the world’s experience of using the method, indications and contraindications are summarized.

Received: 2024-02-28

Published online: 2024-03-31

DOI: 10.47183/mes.2024.015

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VIEWS 349

Mitryashov KV, Mitryashov IV

Hip dysplasia (HD) represents the congenital underdevelopment of the hip joint (HJ) being the most common orthopedic problem of newborns having the prevalence of 5–20%. Late HD detection is the main cause of coxarthrosis in young adulthood. The study was aimed to assess the results of ultrasound screening for HD in infants. The study involved 860 full-term infants aged 1–3 months (446 boys (51.9%) and 414 girls (48.1%)). All newborns underwent ultrasound imaging of the hip joint at the age of 1 month and the follow-up examination at the age of 3 months (Graf method). The χ2 test and p < 0.05 were used to compare the data. In their first year of life, 685 newborns (79.7%) had joints of normal or transitory shape, 161 (18.7%) showed physiological immaturity and 14 (1.6%) showed the HJ abnormality; the HJ immaturity and abnormality were more prevalent in girls (113 cases (26.3%)) than in boys (62 cases (13.9%)). The relationship between the breech presentation and the likelihood of developing HD was revealed (p < 0.001). Spontaneous improvement by the age of 3 months took place in the majority of infants having the ultrasound signs of HD, the rate of normal HJ increased from 79.8 to 94.5%. Ultrasound screening is an effective method allowing one to detect HD starting from the first days of the child’s life. The risk factors of HD are still female sex and breech presentation, regardless of the number of births. Spontaneous improvement following prescription of relaxing massage occurs in the majority of children.

Received: 2024-02-15

Published online: 2024-03-31

DOI: 10.47183/mes.2024.013

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VIEWS 280