FLUORINE

From Big Medical Encyclopedia

FLUORINE (Fluorum, F) — chemical element VII of group of a periodic system of D. I. Mendeleyev: treats biomicroelements. T. plays a significant role in development and a mineralization of bones (ShM. Bone) and teeth (see); treats microelements, absolutely necessary for an organism, (see). In medicine nek-ry fluorochemicals apply as pharmaceuticals, including used for an anesthesia (see the Anaesthesia, t. 20, additional materials), as blood substitutes (see Krovezamenyayushchy liquids), etc. Connections F. are toxic and on the productions connected with their receiving or use can represent professional harm.

For the first time in an elementary state F. H. Moissan by hydrolysis of the anhydrous hydrogen fluoride containing additives of potassium fluoride was received in 1886.

On the content in crust (6,5-10-2% ps to weight) F. takes the 12th place among chemical elements, in rocks its concentration on average makes 300 — 800 mg/kg, in soils — from 30 to 320 mg/kg, in superficial water sources — 0,1 — 0,8 mg/l, (up to 6 mg/l more rare), in underground waters — to 20 mg/l and more, in sea water — 0,7 — 1,4 mg/l, in free air — from

2 - 1do 4-10 "4 mg/m3. T. is an osteotropny element: in teeth and bones of the person and animals his contents reaches 2000 mg/kg and above, it averages 240 — 560 and 200 — 490 mg/kg respectively.

Sources F., coming to the biosphere, the volcanic gases containing up to 2,5% of fluorine and volcanic rocks are, in to-rykh it is revealed apprx. 90 fluorinated minerals. In the second half of 20 century a considerable part coming to the biosphere F. represents result of technical activity of the person. For the person the following fluorinated minerals have the greatest value: Sak2 fluorite (fluorspar), Na3AlF6 cryolite, Ca5(P04) 3F fluorapatite.

T. treats halogens (see) together with chlorine (see), bromine (see), iodine (see) and a radioactive chemical element astatine (a chemical At symbol). Atomic number of fluorine 9, atomic weight (weight) 18,998. Along with a stable isotope of fluorine — 19F 5 artificial radioisotopes are known: 16F with the period on

a luraspad (T1/2) less than 1 ms., 17F(T1/2 = 70 sec.), 18F (T1/o=lll min.), 20F (Ti/2 = 11,4sek.) and 21 F (1u2 = 5 sec.). Radioactive F. receive radiation by stable 19F deuterons in a cyclotron.

Short half-life of radionuclides of fluorine complicates their practical use. The most long-living of radionuclides of fluorine 18F belongs to positron radiators f + — 97%, electrons of capture — 3%) and is the only radionuclide F., finding application in radio isotope diagnosis, and also in medicobiological researches. The value of l8F for medicine consists that it, being to about r about t to about and in at Russian cabbage soup of m a nuclide, gives the chance of obtaining extensive diagnostic information at the minimum radiation of investigated. There is an experience of use of fluoborate of potassium, and also sodium fluoride for diagnosis of bone pathology and studying of exchange processes in the mineralized solid tissues of teeth and a skeleton. Works on creation of the various radio pharmaceuticals containing in quality of a tag 18F are conducted to-rye can be used, e.g., for obtaining tomograms (see the Tomography). For assessment of regional metabolism in a brain use 18P-glucose. Diagnostic information during the work with 18F is obtained by definition of the doctrine, annihilation at-from l.

T. represents pale yellow gas with a specific pungent smell, * °kip — 188,13 °, at t ° — 188 — 213 ° it is condensed in liquid of yellow color, at f — 219,6 ° hardens. T. differs in extremely high reactivity and forms connections with all elements, including with nitrogen and heavy rare gases. Reactions of direct fluoration proceed on the chain mechanism and can often turn into burning and explosion. Exclusive reactivity F. causes its high biol. activity.

With water F. mixes up in every respect, forming fluoric to - that H2F2. At a temperature over 90 °' fluoric to - that has a formula of HF; thus, it can form both average (fluorides), and acid (bifluorides) of salt.

Insufficient receipt F. in an organism is one of exogenous etiol. factors of caries of teeth (see), especially during their eruption and a mineralization. An effective measure against caries is fluoration of water (see) before optimum contents in it F. (apprx. 1 mg/l). This method is developed with the assistance of the Soviet scientists and recommended to WHO for distribution in all countries. T. it is possible to enter into an organism also in the form of additive in sodium chloride, milk or to accept in the form of tablets. Locally fluorochemicals (NaF sodium fluoride, Na2SiF6 sodium fluosilicate, etc.) apply in the form of applications, rubbing in of pastes, solutions, gels, etc. For rinsing of an oral cavity solutions of sodium fluoride use 0,1 — 0,2%.

T. stimulates reparative processes at fractures of bones, prevents development of senile osteoporosis (see). There are data that F. reduces accumulation of strontium (see) in a bone tissue also reduces weight of the damages caused by radioactive strontium. At hron. influence of rather small doses F. stimulation of reactions of immunity while at long action of high doses of this element (e.g., on the corresponding productions) noted oppression of protective forces of an organism is observed.

Daily requirement in F. at adults makes 2 — 3 mg. With foodstuff the adult receives on average 0.8 mg of fluorine, other quantity F. shall arrive with drinking water.

Excess receipt F. in an organism (generally with drinking water or at pollution of the atmosphere emissions of the industrial enterprises), bringing to hron. intoxications F., is an origin of a fluorosis (see), to-ry affects generally second teeth of people, since the birth or the early childhood living in the centers of a local fluorosis. Toxic action F. it is connected with inhibition it many fermental systems.

Addition of atom F. in molecules of various biologically active compounds, napr, steroid hormones (see), often raises them biol. and pharmakol. activity (see Dexamethasone, Triamcinolonum, etc.). Ftorproizvodnye of a pyrimidine, e.g. ftoruratsit (see), ftorbenzotef (see), use in chemotherapy of tumors, Ftorotanum (see) — 1,1,1-trifluoro-2-chlorine-2-bromine-ethane — for an inhalation anesthesia.

Determine content F. colorimetric (see Colorimetry), elektrometrichesk with a ftorselektiv-ny electrode (see the II otentsiomet-richesky titration), titrimetric (see. The titrimetric analysis) or gazokhromatografichesk (see the Chromatography), is more rare by amperometry (see Amperometrichesky titration), mass spektrome-trii (see) and other methods.

Fluorine as professional harm. At production and enrichment of fluorite, processing of apatites and phosphorites, in production fluoric to - you, fluoric salts, etc. in air of production rooms gaseous F2 fluorine, HF hydrogen fluoride, etc., and also aerosols of salts F can be emitted. — NaF, AlFg, CaF2, etc.

In conditions of production and environmental pollution by fluorinated industrial emissions F. can come to an organism with air and through the unimpaired skin. T. it kumulirutsya in highly mineralized fabrics. At excess receipt in an organism F. has toxic effect, character and weight to-rogo depend on physical. - chemical properties of connections F., doses, exposures, ways of receipt to an organism and age of the victim. Gaseous connections F are most toxic. Toxicity of aerosol fluorides increases in process of increase in their solubility. Inhalation receipt F. in an organism it is more dangerous peroral.

Selective toxic effect F. on any fabric or function it is not observed. The nature of changes in fabrics and bodies depends not only on a way of receipt F. in an organism and a type of fluorochemical, but also from a dose, and also a rhythm of its receipt. If at single or short-term receipt of bigger quantity F. in an organism (inside) first of all suffers central and the autonomic nervous system, and also parenchymatous bodies, at long receipt of rather small doses (most often — with water in the local centers of a fluorosis), not capable to cause acute poisoning, first of all the dense mineralized fabrics — bones and teeth suffer. Transfer of patterns of action F., established in acute experiences, on its condition hron. leads influences to the wrong conclusions. Strongly established fact is very important for practice that in the conditions of long receipt of excess quantities F. with drinking water first of all teeth are surprised. In the local centers of a fluorosis no other defeats, except changes of teeth and a skeleton, are found.

Hron. professional intoxication F. — a professional fluorosis — the oiisana is also studied quite in detail. At this type of a fluorosis damages of teeth, bones, a hemorrhagic syndrome, a bronchospasm, damage of a myocardium, liver, change of a picture of blood are noted.

Treatment hron. poisonings F. symptomatic.

At acute inhalation poisonings with gaseous connections F. (cases of acute inhalation poisoning with aerosols of connections F. are not described), possible at emergencies and non-compliance with safety regulationss, there are sharp irritation of eyes and upper dykhatelngkh ways, a morbidity and a rhinedema, an ulceration of a mucous membrane of a nose and an oral cavity, a conjunctiva, and also nasal bleedings, sometimes vomiting, suffocation, attacks of a tetany. Disturbance of cardiovascular activity (falling of the ABP, conductivity change of a myocardium, disturbance of coronary circulation), development of toxic hepatitis, a nephropathy is possible; in blood increase in number of erythrocytes and strengthening of hemoglobin, a leukopenia, neutropenias, a relative lymphocytosis comes to light; ROE is slowed down.

Diagnosis of acute poisoning F. put on the basis of a production situation and characteristic a wedge, pictures of poisoning.

Outcome of acute inhalation poisonings with connections F. there can be bronchitis (see), a pneumosclerosis (see), bronchiectasias (see the Bronchoectatic disease), dystrophic changes of a myocardium (see the Myocardial dystrophy), damages of a liver; in hard cases death can be caused by damage of lungs (hemorrhages and hypostasis).

At accidental intakes of a large amount of fluorinated substances throat, gullet pain and an anticardium, thirst, hypersalivation, plentiful sweating, vomiting, a diarrhea, muscular weakness, falling of the ABP, fervescence, an asthma, weakness of cordial activity, fibrillar twitchings of muscles, spasms are noted.

First aid and emergency treatment at acute poisonings with gaseous connections F. consist in transfer of the victim on fresh air, purpose of heatwet soda inhalations, inside — codeine, dionine, Dimedrol, drugs of calcium, expectorating and calmatives. In hard cases intravenously enter calcium chloride, cardiovascular means; appoint oxygen, antibiotics; immediate hospitalization is required. At poisoning with the fluorides accepted inside it is necessary to make as soon as possible a plentiful gastric lavage via the probe of 2% solution of hydrosodium carbonate, to give to the victim salt laxative, atropine under skin repeatedly. Further treatment * symptomatic.

Examination of working capacity. At not serious poisoning F. injured temporarily transfer to other work before the termination of a course of treatment. At a serious poisoning with development of permanent disturbances of health (hepatitis, a nephropathy, etc.) discharge from work about professional harm-nostyyu and rational employment is recommended.

Prevention of poisonings with fluorine consists in prevention of allocation in air of production rooms gaseous F. and its connections, in particular in the form of aerosols; sealing of the equipment and communications, use of materials, resistant concerning corrosion, effective ventilation (see), use of industrial gas masks of brand B (see Gas masks), respirators on the basis of ionite fiber or the Petal In brand (see Respirators), overalls (see Clothes special), rubber gloves and boots (see Footwear), observance of measures of personal hygiene, prohibition of smoking and meal in a workplace, preliminary and periodic medical examinations are necessary (see. Medical examination). Women during pregnancy and feeding of the child shall be exempted from work with fluorine.

Fluorine in the medicolegal relation. In court. - medical practice accidental (more rare for the purpose of suicide) acute poisonings with sodium fluoride, sodium fluosilicate, sometimes fluoric to - that, and also organic compounds F most often meet. (see Fluorine organic it is connected iya), it is frequent with a lethal outcome. A lethal general dose for the person at introduction to a stomach of sodium fluoride — 5 — 10 g, sodium fluosilicate — 4 — 5 g. The phenomena of poisoning at introduction to a stomach of fluorinated substances develop quickly. Death comes owing to paralysis of a respiratory center or an acute heart failure. Terms of experience at poisoning F. of 15 — 20 min. till several o'clock or days.

During the opening often note irritation zhel-.kish. a path sometimes with the phenomena of a superficial chemical burn of a mucous membrane, a plethora, dystrophic changes of internals, liquid blood (but sometimes blood parcels), hypostasis of a brain. Histologically (at poisoning with sodium fluosilicate) in a myocardium intersticial hypostasis, a fibrinoid necrosis are noted; dot hemorrhages in a brain, a pancreas, adrenal glands, proteinaceous dystrophy of parenchymatous bodies, a necrotic nephrosis, erosive gastritis, hemorrhagic enteritis, focal necroses of a liver.

Court. - chemical definition F. it is based on destruction of the studied objects sulfuric and chloric to-tami with a simultaneous otgonka of the formed hydrogen fluoride with water vapor. In distillate ions F. find reactions of coloring (with lanthanum and alizarinkompleksony, with use of complexes of zirconium with eriokhromtsianiny R) and breakdown of etching of glass. Quantitative definition is made photometric with use of complexes of zirconium with eriokhromtsianiny R. At assessment of results of the analysis it is necessary to consider naturally contained fluorides in fabrics of bodies and biol. liquids.

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V. A. Knizhnikov (I am glad.), S. V. Scherbakov

(gigabyte.).,

Яндекс.Метрика