ZINC

From Big Medical Encyclopedia

ZINC (Zincum, Zn) — chemical element II of group of a periodic system of D. I. Mendeleyev. Zinc is carried to microelements (see), necessary for normal life activity of the person, it is a part of a karboangidraza (see), the enzyme participating in maintenance of acid-base equilibrium (see) and other metallofer-cops (see Metalloproteins). C. influences activity of triple hormones of a hypophysis (see), participates in implementation biol. effects of insulin (see), has lipotropic properties, normalizing a lipometabolism (see), increasing intensity of disintegration of fats (see) in an organism and preventing fatty dystrophy of a liver. There are C given about participation. in a hemopoiesis (see); C. it is necessary for normal functioning of a hypophysis (see), a pancreas (see), seed bubbles (see) and a prostate (see). Connections C. in medicine use as pharmaceuticals. Lack or surplus of an organism of C. causes disturbance of synthesis and properties of the corresponding metalloproteins, and also others, metalloorganic compounds necessary for an organism (see). Many connections C. apply as insecticides (see), fungicides (see), preservatives to wood, lubricant dopes, components of a number of dyes, phosphors, etc. Zinc is a component of brass, a German silver, tombac and other alloys, is used for a corrosion-resistant coating (galvanizing) of steel and cast iron. On the productions connected with receiving and use of C. and its connections, it can represent professional harm-nost.

C. atomic number 30, atomic weight (weight) 65,37 is metal of silver-white color. Pure C. it is received in 16 century, before it was known only as a component of brass.

Natural C. consists of 5 stable isotopes with mass numbers 64 (48,6%), 66 (27,9%), 67 (4,1%), 68 (18,8%),

70 (0,6%). Also 15 radioisotopes C are known. with mass numbers from 57 to 79 (except 58 and 59), two of to-rykh have nuclear isomers (see the Isomerism, an isomerism of atomic kernels). Radioactive C. it is applied in the different fields of science ii of the equipment as tracer, and also in biol. researches, napr, during the studying of exchange of C. in an organism and clarification of a role of this important microelement in life activity of animals and plants. Connections, marked in radioactive C., represent various salts C., hl. obr. zinc chloride.

09 mZn receive radiation by neutrons in the nuclear reactor of zinc targets of natural structure or targets enriched on isotope 68Zn on nuclear reaction of tt8Zn (n, v) 69 mZn. 65Zn receive in the nuclear reactor radiation by neutrons of natural zinc on reaction of e4Zn (n, v) e5Zn or on a particle accelerator (see) radiation of copper protons of a pla deuterons on reactions 64Cu (r, n) 65Zn or e3Cu (d, 2n) eaZn.,

On radio toxicity of 69 mZn and 65Zn treat group B. The radioactive C entered into an organism of animals. collects preferential in a hypophysis, a liver, pancreatic and prostatic glands; the C is allocated. hl. obr. through went. - kish. path.

Crust contains 8,3*10-3% of zinc on weight, generally as a part of polymetallic sulfide ores and minerals, from to-rykh the main are sphalerite (blende) and vyurtsit ZnS, ZnC03 smithsonite, ZnO zincite, a calamine of Zn4[Si207] (0H)2*H20.

The human body contains on average 2 — 3 g of zinc (i.e. approximately as much how many and gland, and in 10 — 25 times more, than copper). The highest concentration of C. note in a prostate (about 15 mm), ion concentration of Zn2 + in fabrics averages 0,3 — 0,5 mm.

Metal C. represents substance with the geksagonichesky densely packed crystal lattice, density of 7,133 g/cm3, * °pl419,50, g°kip 906 °. In connections C. shows valency +2. In a humid air and water this metal is stable up to temperature 200 °, its oxidation is interfered by a top skin of hydroxy carbonates. C. reacts with to-tami and alkalis, ammonia, salts of ammonium, wet molecular chlorine and bromine, during the heating — with molecular oxygen.

The ion of Zn2 + contacts the majority of organic compounds much stronger, than an ion of Mg2 + (see Magnesium) and aims to form four covalent bonds of tetrahedral symmetry; unlike magnesium, to-ry quickly and reversibly the C interacts with enzymes (see). finds a tendency to strong linkng with fermental protein. Ions + are necessary for Zn2 for functioning of a karboangidraza, a thermolysine, dipeptidases (see Peptide hydras about manholes), alkaline phosphatase (see Phosphatases), RNA - and DNA polymerases (see Polymerases), nek-ry zymohexases (see), alkogoljde-hydrogenases (see) and superoxide dismutases (see Radicals free). It is known that C. contacts hexamers of insulin. At many carnivores and the person the reflecting layer behind a retina contains crystals zinc - cysteic go a complex. It is established that with C. copper ions of Si2 + and Cd2+ cadmium compete. Ions + are very toxic Cd2 and have ability to collect in cortical substance of kidneys, forcing out C.

Determination of C. in biol. material carry out by methods of issue, atomic and absorbing, X-ray spectroscopy (see Spectroscopy) and other methods qualitative and quantification.

At usual food of gipotsin-goats at the person develops extremely seldom — only at sharp disturbances of balance of food (see. Balanced food), and also at disturbances of absorption and removal of zinc. Diets with very high content of grain products can become the reason of insufficiency of C. at the person since they are rich phytin to - that, edges interferes with absorption of salts C. from intestines in blood. Insufficiency of C. it is shown in delay of growth and an underdevelopment of generative organs at youthful age. Milk contains few C., therefore for babies the early feeding up by vegetable and fruit juice — sources not only vitamins and copper, but also Ts. Potrebnost in C is recommended. makes (mg a day): at adults — 10 — 15; at pregnant women — 20; nursing mothers 25; children — 4 — 5; children of chest age have 0,3 mg on 1 kg of body weight. In food stuffs the average content of C. makes (mkg on 100 g of an edible part of a product): in beef liver — 5000, pork liver — 4000, beef — 3240, a yolk of egg — 3105, Dutch cheese — 3000, in split peas — 2440, meat of a rabbit — 2310, white bread from the whole grain — 2132, hens (carcass) — 2055, buckwheat — 2050, a grouper — 1534, a cod — 1020.

Zinc as professional harm. In the industry the metal C is used. and its connections. ZnO zinc oxide is applied as a pigment to white paints, in production of rubber, glass, ceramics, matches, dentist's plaster, cosmetics, and also as a filler of rubber and in a galvanoplasty. In workrooms of ZnO can be present also at a type of a high-disperse aerosol of condensation at the technical processes connected with on-grevaniyekhm C. higher than temperature of its melting. Chloride and zinc sulfate apply to conservation of wood, in pulp and paper industry, in production of viscose rayon, zinc mineral colors, as gumboil at hot galvanizing, a tinning, the soldering.

Metal C. and its connections under production conditions come to an organism of hl. obr. through a respiratory organs and partially through a digestive tract as a result of swallowing dust. Toxic effect of vapors C is most of all studied. and a finely divided aerosol, to-rye are formed in the course of melting of metal of zinc oxide. At their inhalation in considerable concentration there can be a prof. a disease — so-called zinc, or foundry fever (see). Soluble salts C. have the considerable cauterizing effect on skin and mucous membranes.

At hron. poisoning with oxide C. atrophic and subatrophic changes of a mucous membrane of upper respiratory tracts, hypochromia anemia can develop, went. - kish. frustration, sleep disorders, increased fatigue, sonitus, decrease in auditory acuity. At long influence ached oxide D. on a human body perhaps development of slowly progressing pneumoconiosis (see

the II nevmokonioza). At long inhalation of dust of oxide C. in considerable concentration the moderate phenomena of a pneumosclerosis (see) and emphysemas of lungs develop (see), is more rare — a melkopyatnisty disseminapiya in connection with adjournment of X-ray contrast dust of oxide C. in lungs; the urobilinuria (see) and a purpurinuria is possible (see Porphyrines). On the back of brushes (preferential) note irritation and ulcerations of skin.

Wedge, picture hron. poisonings with chloride C. it is connected from it sharply by irritant action on mucous membranes and on skin, up to development of dermatitis (see), and also poorly allergenic action on an organism. Inhalation of smoke of chloride C. makes cough, sick, an inflammation in upper respiratory tracts, bronchial tubes, lungs. In hard cases the perforation of a nasal partition is possible.

Irritant action also sulfate and stearate C possess. Dry sulfate C. and its concentrated solutions cause ulcerations of skin of hands, especially their dorsum, as so-called bird's eyes. Experimental data about oncogenous action of C are obtained. and its connections.

Acute poisoning with connections C. noted at inhalation of oxide C. in high concentration (e.g., during the heating of metal C. higher than temperature of its melting). Victims have a sweetish smack in a mouth, in

1 — 5 hour there is a strong thirst, painful constraint in breasts, dry cough, a fever and other symptoms of foundry fever. At inhalation of an aerosol of chloride C. the fluid lungs can develop (see).

At poisoning with soluble salts C. through a mouth at victims also note metal taste in a mouth, nausea, hypersalivation is observed, the burn of a mucous membrane of a mouth, gullet, stomach develops, there are vomiting with impurity of blood, an abdominal pain, a diarrhea, sharp excitement, involuntary twitchings of separate groups of muscles, spasms of gastrocnemius muscles, the collapse and shock is possible. At longer course of poisoning the acute renal failure develops (see).

P e r in and I am ii about m about shch and and e-turn-down those ra p and I at acute poisonings with soluble salts C., especially at their peroral receipt, consists in a gastric lavage via the probe of 3% solution of hydrosodium carbonate or 2% solution of a tannin, purpose of Unithiolum, intravenous administration of glucose with ascorbic to - that, Calcium chloratum, drink of alkaline mineral waters, warm milk, mucous broths, purpose of salt laxatives. At inhalation poisonings of C. and its connections apply irednizolon or other glucocorticoids.

Further treatment, as well as treatment hron. poisonings of C. and its connections, symptomatic.

Prevention of poisons l e N and y c and ii to about m and e about with about piece and N e N and I am m and consists in mechanization and sealing of the processes connected with melting of non-ferrous metals and other works, creation of rational local and general ventilation (see), use of individual means of protection — respirators (see), industrial gas masks (see), protective ointments or fat creams, etc., washing of hands alkaline solutions.

E to with ii e r t and z and t r at d about with p wasps about N about with t and. Questions of examination of working capacity, medical and labor rehabilitation at intoxications of C. and its connections decide taking into account expressiveness of symptoms of intoxication and a gigabyte. characteristics of working conditions. At considerable damages of skin temporary disability or transfer into other work are possible. Persons about a wedge, displays of foundry fever of a pla acute and hron are temporarily disabled. intoxications of C. and its connections with serious defeats of a respiratory organs and digestive tract. To permanent disturbances of working capacity acute and hron. poisonings of C. and its connections usually do not bring.

Maximum allowable concentration in air of a working zone for oxide C. makes 0,5 mg! m3.

M and N and m and l and about significant and to t and in N about with t 65Zn, not demanding registration or obtaining permission of bodies of the State sanitary inspection, to 10 mkkyura (37 kBq).

Zinc in the medicolegal relation. Poisonings of C. are extremely rare, generally meet at steam inhalation or smoke of oxide C. or intake on imprudence or with the suicide purpose of the so-called soldering fluid containing chloride C., zinc vitriol (zinc sulfate) or phosphide of zinc. On opening at the dead from poisoning with chloride C. find out that the mucous membrane of an oral cavity and a throat is, as a rule, wrinkled, covered with a white plaque, note a burn and profound necrotic changes of a mucous membrane of a gullet and stomach with possible perforation, focal pneumonia, dystrophy of kidneys, a liver and myocardium.

Court. - chemical determination of C. in biol. material carry out after a mineralization of tests concentrated by a chamois and nitric to-tami a fractional method. Existence of ions of C. establish a white deposit of sulfide by training or a geksatsianoferroat of zinc, colourless wedge-shaped microcrystals of tetrarhodanomeasures-kuroata of zinc or pink coloring of a chlorouniform layer due to extraction by chloroform of the formed ditizonat of zinc. Quantitative determination of C. carry out by a kompleksonometrichesky method (see Nompleksonometriya). By drawing up the conclusion about poisoning of C. as to a cause of death consider the natural maintenance of C. in bodies, fabrics and fluid mediums of a human body.

Drugs of zinc. As drugs C., used in modern medical practice, apply zinc sulfate and Zinci oxydum. Zinc sulfate belongs to well dissociating salts C., and Zinci oxydum is almost water-insoluble and nearly week the connection Associating it. Zinc sulfate at topical administration shows antiseptic properties and depending on concentration renders knitting (0,1 — 0,5% solutions), irritating or cauterizing (higher concentration) action that is caused specific biol. action of ions of C., formed in the course of dissociation of zinc of sulfate. The antimicrobic (antiseptic) effect of drugs of zinc of sulfate is connected with the fact that ions of C. like ions of other heavy metals interact with sulphhydryl groups (see) enzymes of a microbic cell also cause their inactivation, promoting thereby death of microorganisms (see. Antiseptic agents). The knitting and cauterizing effects of zinc of sulfate are caused by ability of ions of C. to form with proteins of fabrics albuminates that leads to education on a blemished surface of skin or mucous membrane of a protective film or (in case of the cauterizing effect) to a necrosis of fabrics (see Astringents, Caustics). At intake of zinc sulfate reflex causes vomiting due to irritant action went on a mucous membrane. - kish. path; owing to absorption of ions of C. intoxication these ions can develop. The ions of C which are soaked up in blood. are deposited generally in erythrocytes, and also in a liver, a pancreas and nek-ry other bodies. Allocation of ions of C. from an organism (to 30% of the accepted dose) happens slowly, generally to urine and a stake. Zinc sulfate is used by hl. obr. outwardly as antiseptic and astringent. As cauterizing and vomitive this drug in modern practice is almost not used.

Zinci oxydum unlike zinc of sulfate has generally adsorbing properties and has rather weak antiseptic and knitting effect. The last is caused by very low extent of dissociation of Zinci oxydum but to comparison from zinc sulfate. For the same reason after intake of Zinci oxydum the emetic effect and signs rezorb-tivny action of ions of C is not observed. Zinci oxydum apply outwardly as adsorbing, knitting and antiseptic agent.

Zinc sulfate (Zinci sulfas; synonym of Zincum sulfuricum; GFH); ZnS04*7H20 — colourless transparent crystals or inodorous fine-crystalline powder. On air disappears. Water solutions have acid reaction. Let's very easily dissolve in water, it is almost insoluble in alcohol, we will slowly dissolve in 10 h glycerin; pier. weight (weight) 287,54. Apply as antiseptic and astringent at conjunctivitis (0,1; 0,25 and 0,5% solutions), hron. laryngitis (0,25 and 0,5% solutions), and also for syringings at uretrita and colpitises (0,1 and 0,5% solutions). As vomitive it is appointed inside on 0,1 — 0,3 g to reception. The highest single dose for adults in 1 g (once).

Form of release: powder; eye silt and (0,25% or 0,5% solution of zinc of sulfate and 2% solution boric to - you) in bottles on 10 ml. Eye drops from zinc sulfate are issued also in polyethylene tubes droppers of ito of 1,5 ml. Storage: in I bury to the corked

container; joint venture. B.

Zinci oxydum (Zinci oxydum; synonym of Zincum oxydatum; GFH); ZnO — is white r.rii or inodorous amorphous powder, white with a yellowish shade. It is almost water-insoluble also alcohol, we will dissolve in solutions of alkalis, divorced mineral to-takh, and also in acetic to - those; pier. weight (weight) 81,37. Apply outwardly in the form of powders, ointments and pastes as the drying, knitting and antiseptic agent at various skin diseases. Form of release: powder.

Zinci oxydum is also a part of a number of ready dosage forms: Galmaninum (Galmaninum) —

powder contains Zinci oxydums of 10 h, salicylic to - you are the 2nd h,

talc and starch on 44 q.; linimentum of zinc oxide (Linimentum Zinci oxydi) contains Zinci oxydums

of 1 h, sunflower oil 1,5 of h; zinc oxide ointment (Unguentum Zinci) contains Zinci oxydums of 1 h, vaseline 9 of h; ointment tsinko-naftalanny with anaesthesin (Unguentum Zinci naphthalanum cum Anaesthesino) contains zinc oxide ointment 79,2 g, ointments of naftalanny 15,8 g and anaesthesin

of 5 g; paste zinc (Pasta Zinci) contains Zinci oxydum and ito 1 starch of h, vaseline 2 of h; paste salicylic and zinc (Pasta Zinci-sali-cylata; the synonym JIaccapa paste) contains Zinci oxydum and wheat starch on 25 h, salicylic to - you

are the 2nd h, vaseline 48 of h; paste tsinko-naftalanny (Pasta Zinci-naphthalani) contains Zinci oxydum and starch according to 1 h, ointment of naftalanny 2 h; paste tsinko-Ichthyol (Pasta Zin-ci-ichthyoli) contains Zinci oxydums

of 24.4 g, Ichthyolum of 2,5 g, starch

of 24.4 g, vaseline of 48,7 g; powder the nursery (Aspersio puerilis) contains Zinci oxydums of 1 h, starch 1 of h, talc 8 of h Besides, Zinci oxydum is a part of candles of «Neo-Anuzol» (Suppositoria «Neo-Anuso-lum»).

Bibliography: Harmful substances in the industry, under the editorship of N. V. Lazarev and I. D. Gadaskina, t. 3, page 370, L., 1977; To r y l about in and A. N. Issledovaniye of biological material on «metal» poisons by a fractional method, M., 1975;

Levin V. I. Receiving radioisotopes, M., 1972; Mashkovskiym. Of Le

karstvenny means, p. 2, M., 1984; Acute management at acute poisonings, under the editorship of S. N. Golikov, page 128, M., 1977; Standards of radiation safety of NRB-76, M., 1978; P about l and N of of L. The general chemistry, the lane with English, M., 1974; Occupational diseases, under the editorship of A. A. Letavet, etc., M., 1973; The Guide to forensic medical examination of poisonings, under the editorship of R. V. Berezhny, etc., page 107, M., 1980; The Reference book on professional pathology, under the editorship of L. N. Gratsianskaya and

V. E. Kovshilo, page 345, L., 1981; At and y t And. and d river. Fundamentals of biochemistry, the lane with English, t. 1 — 3, M., 1981; X about l N about in Yu. V. and d river. Characteristics of radiations of the radioactive nuclides applied in the national economy, M., 1980.

A. M. Shaposhnikov; V. V. Bochkaryov (I am glad.),

V. K. Muratov (pharm.), A. F. Rubtsov (court.), N. A. Senkevich (gigabyte.).

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