Vol 31, No 2 (2024)

BACKGROUND: Dioxins, furan, and its derivatives are hazardous environmental pollutants that also permeate human biological systems. Dioxins are recognized as global ecotoxicants with potent mutagenic, immunosuppressive, carcinogenic, teratogenic, and embryotoxic effects. These compounds are resistant to degradation and bioaccumulate in both the human body and the planet’s biosphere, encompassing air, water, and food sources. The lethal dose for these substances can be as low as 10−6 g per kg of human body weight. The International Agency for Research on Cancer classifies furan as ‘possibly carcinogenic to humans’ (Group 2B). Inhalation of furan has been shown to induce pulmonary edema and bronchial necrosis. An experimental study involving a single oral administration of furan in corn oil at 4 cm³/kg body weight in Fischer 344 rats demonstrated that furan doses of 0.1–0.2 mg/kg body weight can oxidize into the toxic metabolite cis-2-butene-1,4-dial (BDA), which is pivotal in mediating toxic effects. A dose of 250 µg/kg body weight was found to induce chromosomal aberrations in male Fischer 344 rats. Furan is considered a non-genotoxic hepatocarcinogen; it undergoes hepatic metabolism to form the metabolite cis-2-butene-1,4-dial (BDA), which exhibits acute toxicity towards hepatocytes. Consequently, cell death is accompanied by tissue regeneration and cellular proliferation, thereby increasing the risk of carcinogenesis.

AIM: To examine international experience, scientific and informational sources, and the results of theoretical and experimental research, as well as methods and techniques for determining the mass concentration of dioxins, furan, and its derivatives in human biological media.

MATERIAL AND METHODS: The study focused on both Russian and international sources of scientific and methodological literature pertaining to the toxic compounds of dioxins, furan, and its derivatives. A comprehensive analysis of the scientific literature was conducted on the methods and techniques for determining the mass concentrations of furan and its derivatives in human biological media, as sourced from Google Scholar. Methodological documents currently in effect in the Russian Federation were searched on the websites http://www.normacs.ru and https://files.stroyinf.ru. The temporal scope of the analysis spanned 37 years, from 1986 to 2023.

RESULTS: The review provides an in-depth description of the physical and chemical methods employed to monitor levels of dioxins, furan, and its derivatives in biological media; their toxic and genetic effects; and the absorption, distribution, metabolism, and excretion of furan from the body. It also covers the toxicological properties of furan and its derivatives, based on animal experiments conducted on Fischer 344 mice and rats in EU countries and the USA.

CONCLUSION: The review summarizes the experience gained from international studies in EU countries and the USA, which can be used for developing human biomonitoring and for implementation into practical activities as a sub-system within social and hygienic monitoring in the Russian Federation.

BACKGROUND: Synchronization of biorhythms in living organisms is of particular interest to researchers from the standpoint of adaptation theory.

AIM: To study the characteristics of the response of regulatory influences on heart rhythm during tests with voluntary breath holding during inhalation and exhalation.

MATERIAL AND METHODS: The study sample included 21 randomly selected students (9 males, 12 females) aged 20.64±1.14 years with body weight 67.19±12.98 kg, height 172.29±7.63 cm. All subjects were divided into three groups (I, II, III) according to the classification by N.I. Shlyk (2009), which is based on the predominance of central or autonomic circuits of heart rhythm regulation. A fivefold sequential ECG recording was conducted using the hardware-software complex “Varicard 3.0” with the subject seated after a five-minute rest: 1 — baseline state; 2 — voluntary breath holding during inhalation; 3 — resting state; 4 — voluntary breath holding during exhalation; 5 — resting state. Using the “Varicard 3.0” system, a mathematical analysis of heart rhythm was performed, taking into account statistical parameters of heart rhythm and indices of spectral frequency analysis.

RESULTS: During the period of breath holding, heart rate variability decreased, while at rest it increased in all groups. In group I, after a breath-hold test during the rest period, eutonia was observed according to spectral analysis (HF=LF). Statistical analysis in this group demonstrated an increase in the contribution of the parasympathetic component to heart rate variability (RMSSD, pNN50, SDNN, CV), signifying the prerequisites for increased heart rate variability. In group II, after breath-holding tests, a slight decrease in sympathetic activity was observed. A tense pattern of autonomic regulation was observed during the exhalation breath-hold test, which may indicate a reduced functional state of the regulatory systems. Group III was characterized by a sharp increase in sympathetic activation in the test with breath holding during inhalation, followed by a soft correction during breath holding during exhalation, which can be regarded as an adequate response of the body to the load. At rest, after the test, the regulation pattern returned to the original one with a moderate predominance of parasympathetic activity and, accordingly, a more favorable level of heart rate variability for the body.

CONCLUSION: Adaptive reactions of the heart rate variability are manifested by an increase in sympathetic activation, which, subsequently, during normal breathing, is replaced by a compensatory activation of the parasympathetic division of the autonomous nervous system. Although reactions are unidirectional, the severity can vary across the groups.

AIM: To study the effect of arterial hypertension on cognitive functions by evaluating the auditory event-related potentials (ERP) Р300 in men aged 60–74 years from the Arctic region of the Russian Federation with the special emphasis on men receiving antihypertensive therapy with controlled arterial hypertension and those who either do not take antihypertensive drugs or take them both regularly and irregularly without controlling blood pressure.

MATERIAL AND METHODS: The study included 64 men with arterial hypertension and 19 men without hypertension (n=19) in Arkhangelsk. Registration of the Р300 and N2 components was performed using the Neuron-Spektr-4/VPM electroencephalograph (Neurosoft, Russia), utilizing the oddball paradigm. Blood pressure (BP) was measured with an automatic tonometer A&D Medical UA-668 (Japan).

RESULTS: In men without arterial hypertension and in those with controlled arterial hypertension, where the median values of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were within normal ranges, there were no differences in the latency (LT) of N2 and P300, nor in the magnitude of the P300 amplitude between these groups. In contrast, men who do not take antihypertensive drugs or receive antihypertensive therapy both regularly and irregularly without controlling their blood pressure, and who have SBP and DBP above normal values, showed an elongation of LT N2 in the parietal (P3), central (C3), and middle temporal (T3) sections on the left, and in the frontal section on the right (F4). There was also an elongation of LT P300 in the middle temporal region on the right (T4) and frontal regions on the right (F4), along with a decrease in the median values of the P300 amplitude in the anterior-temporal (F8, F7) parts of the brain. This indicates a deficit in attention, an increase in the time required for primary recognition and differentiation of signals, and a reduction in the speed of information processing and decision-making.

CONCLUSION: In older men, SBP above 140 mmHg and DBP above 90 mmHg are associated with cognitive impairment as determined by the auditory event-related potentials P300.