NITRITES — salts and nitrous acid ethers. N widely use in the chemical industry for receiving semi-products of production of azoic dyes, add as oxidizers to lubricant cooling liquids, enter into structure of corrosion-resistant coatings. In biochemical and histochemical methods of a research H. use for reactions of diazotization, for quantitative definition of nitrogen of amino groups by Van-Slayka's method (see. Van-Slayka methods ).
Toxic action of N. on an organism is caused by their influence on the vasomotor and respiratory centers of c. N
of page H. are intermediate products of decomposition and a mineralization of nitrogen-containing organic matters. N.'s detection in water and the soil indicates pollution them by nitrogen-containing organic matters.
N. of sodium, potassium, calcium are the most widespread. N — colourless crystals, well water soluble, rather steady in the environment. Water solutions H. easily decay at an elevated temperature and on light. N receive, passing nitric oxides through solutions of caustic alkalis.
Acute poisonings are possible at inhalation of dust or contact with the liquids containing nitrites. They are characterized by a headache, dizziness, nausea, a passing vision disorder, the hyperemia of the person which is quickly replaced by cyanosis; in hard cases there can be spasms, a coma and a lethal outcome from acute oxygen insufficiency.
At systematic impact of lubricant cooling liquids on skin, and also at systematic inhalation of aerosols of these liquids or dust H. workers can have hron, poisonings; at the same time weakness, bystry fatigue, a headache, sleeplessness, extremity and joints pains, in heart, numbness of hands are observed. Instability of the ABP, a hyperexcitability of c is noted. N of page, decrease in number of erythrocytes and thrombocytes, reduction of hemoglobin. The mucosal atrophy of a nose, cyanosis and puffiness of hands, and sometimes and the back of feet because of disturbance of peripheral microcirculation, yellowing of skin of palms, a peeling, cracks and a bubble enanthesis of extremities, fragility of nails are observed.
First aid at N.'s hit in an organism consists in an urgent gastric lavage a suspension of active coal in water, serial giving oxygen and Carbogenum, intravenously enter 10% solution of glucose (at a collapse — 5% solution intravenously, kapelno), subcutaneously physiological solution with adrenaline, cardiacs; at respiratory depression — 1% solution of lobeline.
At hron, poisoning — the termination of contact with N. and carrying out to lay down. actions according to the nature of defeat.
Prevention of poisonings: N.'s replacement in lubricant cooling liquids and corrosion-resistant coatings non-toxic substances or restriction of their contents to 1,5%; an exception of direct contact with N., their solutions and substances containing nitrites. Use of gloves, protective pastes.
Use of nitrites in medicine. Amyle nitrite (see) and sodium nitrite (see) cause short-term decrease in the ABP, however with to lay down. are not applied by the purpose because of possible complications (a collapse, formation of a methemoglobin in blood). In treatment of stenocardia drugs H. have only historical value.
Drugs H. cause expansion of coronary vessels, and also vessels of face skin, retina of eyes, a brain and a firm meninx. At the same time intraocular and intracranial pressure can increase and arise headaches.
Drugs H. are methemoglobin formers. Thanks to this ability they are used in the therapeutic purposes at poisoning hydrocianic to - that and its salts (cyanides). The formed methemoglobin connects cyanides, to-rye block fabric respiratory enzymes. The last are released and can connect oxygen therefore tissue respiration is recovered.
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A. V. Roshchin; G. V. Kovalyov (pharm.).