Vanadium

Vanadium, chemical symbol V, atomic weight 51.0, a hard, elastic metal of steel color, melting point 1715°, specific gravity 5.688. Compounds of V are widely distributed in nature. These compounds are poisons, in strength not inferior to arsenic acid; they possess bactericidal and disinfectant properties. Metallic V is widely used in the production of high-grade steel. Vanadates (salts of V) are used as medicinal agents (Vanadin, Vanadiol, Vanado-form, Vanadozon, Vanadarsin, Citrozon) in tuberculosis, syphilis, anemia.

A. Monoszon. Vanadium is used in the form of ferrovanadium (alloy with iron) in the production of certain especially valuable grades of steel (in the production of various fine tools, parts of automobiles and other mechanisms, etc.), as well as a catalyst, in the mordant for silk-screen printing, in the composition of special developers for color photography or for giving a green tint when printing on bromo-silver paper. About 15 years ago attention was first drawn to V as a professional poison. Jackson conducted a series of experiments on dogs, which showed a rapid increase in blood pressure in the lungs and throughout the entire peripheral circulatory system under the action of V salts. In addition, there occurred a strong increase in the amplitude of respiratory movements as a result of significant contraction of the bronchial muscles. Dutton in 1911 noted that in workers in the production of vanadium compounds, anemia and dry spasmodic cough were considered common occurrences, hemoptysis, irritation of the conjunctiva and mucous membrane of the larynx, gastrointestinal disorders, loss of appetite, etc., were often encountered. Hemorrhagic nephritis was also not uncommon; on autopsies, excessive hyperemia of the kidneys and lungs was found. In addition, a number of nervous phenomena were observed in the form of tremors, headaches, mental disorders, and lesions of the optic nerve. A very similar picture was also described in animals by Cruikshank. At the Congress of the German Society of Occupational Hygiene, held in Wiesbaden in 1926, Lehmann reported his personal observations on workers engaged in adding ferrovanadium to steel: they experienced dizziness, runny nose, and catarrhal phenomena of the upper respiratory tract, sometimes quite significant. The wearing of masks often did not achieve the desired effect. In connection with this, Lehmann conducted a series of experiments with chronic poisoning of animals with small doses of sodium vanadate, which quickly turns in the air into the finest sprayed droplets and is inhaled in this form. In animals, catarrhal phenomena and sharply accelerated respiration were also obtained, which he explains by the action of V on the vagus nerve. With prolonged feeding of animals with V, they lost their appetite, digestion was disturbed, and death often occurred. All the above data require the recognition of V as an indisputable professional poison and the special attention to the adoption of necessary measures to prevent professional poisoning in workers in contact with it. Such measures are all measures to combat dust (see), as well as the replacement proposed by Lehmann of mechanical mixing of finely ground V with iron by their fusion, as a result of which the danger of inhaling vanadium dust disappears.

S. Kaplun. Van Gieson Method, for staining connective tissue. Fixation is indifferent. Sections are stained or even restained in hematoxylin (see), best in Weigert's iron hematoxylin, washed in water for 5-10 minutes, transferred for 1 minute to a mixture of 100 cubic cm of saturated picric acid at room temperature and 10 cubic cm of aqueous acid fuchsin (Fuchsin S.). Rinse in water. Quickly pass through alcohols, carbolic-xylol, xylol and mount in Canadian balsam. Nuclei are stained black, connective tissue - in bright red, elastic tissue, neuroglia, smooth and striated muscles - in brownish-yellow, red blood corpuscles - in yellow, hyalin - in red, colloid - in brownish-yellow. The stain is especially good for differentiating smooth muscle tissue from connective tissue. The stain is not permanent, and after some time the entire section turns yellow. For practical purposes, it is convenient to prepare the picro-fuchsin mixture ex tempore (for 9 drops of saturated solution of picric acid, 1 drop of 1% aqueous fuchsin); with this method of preparation, the staining always results in uniformity. Benda proposed to use, instead of picric acid, ammonium picrate, since this salt is less soluble in alcohols and xylol and the staining is more selective. Take 95 cubic cm of saturated solution of ammonium picrate and 5 cubic cm of 1% acid fuchsin; to this pale-colored basic solution, when used, add for every 10 cubic cm 2 drops of saturated aqueous solution of picric acid. Restained hematoxylin sections are differentiated in this solution for 10-15 minutes, rinsed with water, etc.