Features of the action of ultraviolet radiation on the human body
Compared with infrared radiation, ultraviolet radiation has a very complex effect on the human body, which consists of interrelated biophysical, humoral and neural-reflex phenomena. When the ultraviolet radiation is applied to the human body, biophysical processes primarily develop, while the main one manifests itself in the appearance of a photoelectric effect. As a result of this effect, changes occur in the electronic structure of atoms and molecules, and eventually the electrical properties of the human body and its colloids change, which in some way affects their dispersity. The humoral mechanism of the action of ultraviolet radiation is associated with its influence on the protein substances of the human body, in particular with ultraviolet radiation( only in therapeutic admissible doses), protein denaturation occurs, i.loss of ability to swell, dissolve in water and dilute salt solutions;In addition, protein coagulation is observed in the tissues of the human body. Further, the coagulated protein is relatively easily split by enzymes produced in the human body, which leads to the appearance of protein cleavage products in the irradiated pathological focus, among which are substances with high biological activity, such as histamine, acetylcholine, biogenic amines, etc. It is well known to those skilled in the art,that histamine is an active powerful stimulator of the activity of the smooth muscles of the abdominal cavity, has a vasodilating effect, increases the secretion of the gastrices, generation of pepsin and hydrochloric acid. In addition, histamine is associated with the exchange of adrenaline in the human body, has a certain effect on the exchange of glucocorticoids and catecholamines, increases the activity of the enzyme histamine. The release under the influence of ultraviolet radiation of physiologically active substances of the skin closely connects the humoral mechanism of action with the neuro-reflex, because these substances actively participate in the transmission of nervous excitation.
In the second half of XX century. In the Soviet Union, special studies were conducted on the effect of ultraviolet radiation on the human body, during which the following was established:
• Ultraviolet radiation as a whole is an indispensable environmental factor that is involved in regulating the vitamin balance and metabolic processes of the human body;
• When the skin is irradiated with ultraviolet rays with wavelengths from 302 to 297 nm, vitamin D( 7-dehydrocholesterol) in the body turns into vitamin D 3, which when introduced into the blood promotes the mobilization of inorganic phosphorus, activating the activity of the enzyme phosphatase. The lack of vitamin D decreases the possibility of phosphatase involvement in a number of transformations associated with phosphorus-calcium metabolism.
It is well known that a reduced calcium content in the body( in the bone tissue) causes a decrease in the mechanical strength of bones, a tendency to fracture( ie, osteoporosis is a scourge of children and the elderly), and rickets develop in young children. In addition, the lack of calcium in the walls of blood vessels leads to an increase in their permeability and propensity to exudative reactions( this conclusion was made by the Soviet scientist AP Parfenov);
• In the case of ultraviolet insufficiency, the work of various organs and systems is disrupted, which leads to lethargy, weakness, easy fatigue, decreased muscle performance, a vitamin D and Vitamin C deficiency, which can lead to anemia. A sharp decrease in immunobiological processes in this phenomenon is the reason for the reduced resistance of the human body, especially to colds and infectious diseases;
• under the influence of ultraviolet irradiation, the ratios of protein fractions of blood serum vary, the content of glycogen in the liver and muscles increases;
• Ultraviolet irradiation changes the acid-base balance of the blood: after a short-term acidosis, a longer alkalosis occurs. In addition, the content of proteolytic enzymes varies and the content of catalase decreases;
• Ultraviolet radiation affects the functioning of the cardiovascular system. For example, intensive irradiation of the skin in the erythema zone causes an increase in the rhythm and an increase in the minute volume of the heart, a decrease in blood pressure.
The influence of ultraviolet radiation on blood pressure is explained by shifts in the autonomic nervous system and the appearance in the blood of histamine and histamine-like products that cause the expansion of blood vessels. But with a relatively long-term irradiation, the second phase begins - an increase in blood pressure, therefore, when performing procedures, they strictly adhere to the permissible doses of ultraviolet irradiation;
• Ultraviolet irradiation in certain doses has a desensitizing effect, which is associated with some changes in the functional state of the nervous and endocrine systems, metabolism.
Scientists in the specified years have developed special methods for desensitizing therapy by using ultraviolet radiation for the treatment of a number of diseases in which the allergic component plays a significant role in the etiology and pathogenesis( such as bronchial asthma, rheumatism, allergic rhinitis, etc.).As a rule, the desensitizing effect is manifested only with repeated irradiation or in the case of using a sufficiently intense erythemic dosage( ery-dark dose - the degree of ultraviolet irradiation, which causes the appearance of a peculiar persistent reddening of the skin in the area of the pathological focus);
• With ultraviolet irradiation of the skin at the site of exposure after 2-4 h, persistent hyperemia with clearly defined edges appears - ultraviolet erythema, which lasts from 12 hours to several days. When erythema occurs in the skin, changes occur that are characteristic of inflammation: the expansion of capillaries and their blood overflow, increased permeability of capillaries, etc. In erythemal effects, ultraviolet rays with wavelengths from 257 to 297 nm during the development of erythema in the area of the pathological focus change in endingssensitive nerves of the skin, at the same time hypertrophy and growth of cutaneous nerve cells are noted, their sensitivity decreases, with which the analgesic effect of ultraviolet is associatedradiation. Under the same physical conditions of the impact on the pathological focus, the nature of the erythema depends on many individual characteristics of the organism as a whole. The erythemal skin reaction depends on age, function of the endocrine glands, localization of the effect, and pathological processes occurring in the human body. As the long-term practice of using ultraviolet irradiation for therapeutic purposes has shown, the skin of the face, abdomen, back, and less sensitive skin of the extremities is the most sensitive. In addition, it was noted that the sensitivity of the skin to ultraviolet radiation increases sharply with exudative diathesis, bronchial asthma and various allergic diseases. A sharp decrease in skin sensitivity with similar effects is observed with hypotrophy, infectious diseases.
During clinical trials, it was noted that on the second day at the time of maximum development of erythema, necrobiosis and necrosis of the majority of epidermal cells occurred, by the 3rd-4th day the epidermis thickened due to young cells of the basal layer. By the 7th-9th day, erythema gradually disappeared( under the condition of discontinuation of irradiation), peeling began by dying out the cells of the surface layers of the skin and replacing them with new ones. By the same time period, pigmentation appeared on the site of the erythema, which is the deposition of the coloring substance melanin in the basal cells of the skin.
Clinical observations of UFO procedures have shown that in some cases pigment formation is possible with repeated irradiation and without visible previous erythema.
Prominent Soviet scientist A.P.Parfenov suggested that a good tan on the human body is an indicator of the efficiency of the body's defenses, including sympathetic-adrenal, and this underlies the hardening effect of ultraviolet radiation.
Clinical studies have shown that the formation of erythema skin reaction is accompanied by complex photobiological processes, changes in gas exchange and activity of various enzymes not only in the skin, but also in the body as a whole. From all of the above, it follows that the treatment of any pathological focus in the human body with the use of ultraviolet irradiation( UFV) requires a very deliberate and responsible approach in the appointment of appropriate procedures, including mandatory compliance with the permissible doses of exposure to pathological foci.
In carrying out clinical studies on the use in the treatment of various diseases of short ultraviolet rays( DU), a pronounced bactericidal effect was revealed. The bactericidal effect of FUS is due to their effect on the nuclear substance of the cells of the microorganism. With the absorption of radiant energy by the cells of microbes, the exchange of nucleic acids occurs in them, which leads to cell death. Microorganisms undergo stages of stimulation, inhibition and death.
Direct bactericidal action of KUF is used in medical practice for medical purposes only with superficial arrangement of microorganisms, in particular bacteria. The bactericidal action of this factor in the tissues of the human body is made up of the possible direct action of their( CUF) on the bacteria and especially the changes in the properties of the tissues in which the bacteria are found( in the form of a shift to the acidic side of pH, an increase in the phagocytic activity of leukocytes, etc.)reproduction of bacteria and their death.
Apparatus used in the treatment of various diseases and their prophylaxis using ultraviolet irradiation( UFO)
In the equipment for UVD procedures, a mercury quartz arc lamp( DRT) of high pressure is most often used, which is a short( relatively) quartz glass tube( quartz glassglass passes the ultraviolet rays, and a simple window glass delays them), filled with gas, argon and a small amount of mercury. From both ends of the tube there are metal electrodes, to which an electric current is supplied, as a result, a glow discharge occurs in an inert gas of argon;As a result, mercury evaporates, ultraviolet radiation is produced in its vapors. Lamps of the DRT create a wide spectrum of UV radiation with wavelengths from 250 to 350 nm. In addition to DRT lamps, special erythemic lamps are used in UFO equipment for procedures, which in appearance do not differ from ordinary fluorescent fluorescent lamps;erythemal lamps are used for UV radiation and give a narrow-spectrum radiation of about 297 nm.
In the physiotherapy rooms of polyclinics and the departments of specialized clinics for UFO procedures, the following equipment is used:
• mercury quartz desktop illuminator OKN-11( portable).Such a device has a reflector on the rack and a 230 hr 230 VT lamp, is connected by a cord with a plug to the 220 V power supply. The OKN-11 is equipped with a metal casing that is fixed to the base with four locks-hinges. To transfer this apparatus to the patient's bed, a pen is attached to the body;
• mercury quartz irradiator on the ORK-21 tripod, similar in its device to the OKN-11, is characterized by the presence of a lamp of twice the power - DRT-400( 400 W) and wheels at the base of the tripod for moving it across the floor within the physiotherapy roomsor offices during UFO procedures;
• the nasopharyngeal irradiator UGN-1, which has a 230V DRU-230 lamp, is designed for simultaneous acceptance of the UFO procedure by four patients, each of whom is separated from the adjacent by special curtains fastened on metal brackets;
• lighthouse irradiators type UGD-3 and UGD-2.The first of them is equipped with a lamp D РТ-1 000( 1 000 W), designed for UFO procedures of a whole group of adult patients;the second - for procedures with a whole group of children. The said irradiators have a massive base in which the power supply device is located and a vertical stand, on its upper part a lamp is fixed, and from above it is closed by a protective cap. The base of the irradiators is supported by castors, which allows you to move around the floor of the cabinet or compartment during the procedures. The feed of irradiators is carried out from the 220 V network. UGD-3 is larger than UGD-2, otherwise they are identical;
• the irradiators LCUF-3 and OKUF-5 for short-wave UVA are sources of mainly( up to 85%) short ultraviolet rays with a wavelength of 254 nm. The average bio-dose is provided with UVD from a distance of 20-25 cm for 3-4 minutes. These irradiators are designed to irradiate mucous membranes of the mouth, throat and nose;
• bactericidal irradiators for UVA procedures: BUV-15, BUV-30, BUV-Z0P are equipped with a low-pressure mercury lamp that produces short-wave ultraviolet rays with a pronounced bactericidal effect. The bactericidal mercury lamp has the form of a tube made of special oleo glass. Ultraviolet radiation of bactericidal irradiators on 80/6 consists of short rays with a wavelength of 253.7 nm. For the implementation of UFO procedures, bactericidal irradiators are used: mobile, wall and suspended( or ceiling).The wall irradiator bactericidal is designed for UV treatment of a room with a volume of 30 m. The procedure lasts 1 hour when exposed to an open lamp and 8 hours - when closed( with the condition of continuous operation of the irradiator).Such an irradiator is fixed to the wall at a height of 2-2.3 m above the floor level, but every 2-3 hours of operation it must be switched off for 1-1.5 hours to reduce the concentration of ozone in the air formed when burning bactericidal lamps.
The bactericidal mobile irradiator is designed for UFD within 30 minutes of a room with a volume of 100 m3.
When any bactericidal irradiator is used, it is necessary to protect the eyes by putting on special "canned" glasses with dark glasses( such glasses protect the eyes from light from all directions).After each patient, glasses are wiped with a wet swab soaked with medical alcohol. In addition, in order to prevent burns during UFO procedures, it is also necessary to protect open parts of the body, especially when in a cabinet with a mercury quartz feeder switched on;
• ultraviolet mobile ultraviolet irradiator( erythema), is used for group procedures of UFO( adults and children) for the purpose of prevention( hardening).Such an irradiator produces ultraviolet rays with a length of 247 nm, which have a quenching and anti-ricket effect. This irradiator consists of a base and an upper disc, connected to the base by means of tubular struts. At the very bottom are the elements of the electrical circuit. Between the base and the upper disc in the special cartridges along the circumference there are nine erythemic lamps. In addition, in the center of the base and the upper disc are installed conventional incandescent lamps of 300 watts. The total power consumed by the erythemic irradiator from the mains is 1300 W.The irradiator, if necessary, easily moves on wheels within the room( cabinet or compartment);
• light-emitting sun baths VS-03 with erythemic ovoid lamps EWV-15 and EWV-30( power 15 and 30 W) are designed for UFO procedures individually. These lamps produce ultraviolet radiation with a maximum in the spectral line of 313 nm, which is created by a layer of phosphor deposited on the inner surface of the tube( lamp).Bath BC-03 combined and is designed to irradiate the trunk and extremities with ultraviolet rays in erythematous doses. The surface of the frame of the bath BC-03 is a heat-reflecting metallized fabric. In the same bath can be installed and conventional incandescent lamps for simple thermal procedures.
As clinical studies have shown, erythematous doses of ultraviolet radiation cause the development of processes aimed at desensitization in the human body. In general, ultraviolet erythema is widely used in clinical practice for various diseases. The above-mentioned erythmic lamps are used in children's medical and preventive institutions, living quarters( especially in the conditions of the polar night), industrial and public premises, deprived of natural light. In recent years( 2000-2008) installations with erythemic lamps are widely used in specialized clinics, sanatoriums, as well as in solariums of joint-stock companies.
When performing UFO procedures, special devices are used, which measure the intensity of ultraviolet radiation of all types and types of instruments used. These devices include: ultraviolet( UFM-5), ufidosimeter( UFD-4), portable semiconductor ufimeter( UFI-4).These devices consist of a vacuum photocell, light filters, amplifying circuit and a counter with a scale in which the doses of a certain segment of the spectrum of ultraviolet waves are taken into account. To evaluate UFD, it is very important to know not only the values characterizing the power of ultraviolet radiation, but also the degree of the biological effect it causes.
In medical practice, a method based on the individual sensitivity of human skin to ultraviolet radiation is widely used. This method is simple and is available in all operating conditions. For a unit of dose, this method uses a single biodose - a dose of ultraviolet radiation in time, which causes minimal visible erythema phenomena, at a certain distance from the radiation source.
For a specific biodose in each specific case of UFO procedures, a biodosimeter IF is used. Gorbachev. The biosensor is a metal plate, in which there are 6 rectangular holes 5x15 mm in size, spaced 5-6 mm apart. The plate has a movable cover that covers the holes. The biosimometer with the closed apertures is applied and fixed on the part of the body to be irradiated. After the rest of the skin surface is closed from the action of UFD, the irradiator is placed above the biodosimeter at a distance of 50 cm from the irradiated pathological focus. After that, proceed to irradiation through the holes in the biodosimeter. The first opening of the dosimeter is opened and irradiated for 1 minute, after which a second opening is opened and irradiated again. After every minute of irradiation, a new opening is opened. In general, 6 small patches of the skin, irradiated for 6 lengths of different lengths - from 1 to 6 minutes, are obtained. Due to the fact that the erythema reaction does not appear immediately after irradiation, but after a latent period, the determination of the obtained biodose is made not earlier than 6-8 hours after irradiation. In outpatient settings, the results on the obtained doses of UFO are determined after 20-24 hours. At the same time, the determination of the results of UFO reduces to establishing the dependence of the duration of irradiation and erythema of minimum intensity. If, for example, there are 5 bands of increasing brightness, then, therefore, the bio-dose for a given patient corresponds to 2 minutes when using the prescribed UFO.With a bio-dose equal to 30 seconds from a distance of 50 cm( the standard distance for the determination of the biodosger is 50 cm), the time of one biodose obtained from the irradiator from a distance of 100 cm is found by the formula
X =( 30c * 1002) / 502 = 2 min
Depending on the therapeutic tasks determined during the medical examination, irradiation( UVD) is performed at distances of 25, 50, 75 and 100 cm( the type of irradiator used is necessarily taken into account).