[An experimental study of the effect of vanadium on enzyme indices in chronic oral exposure]. / Eksperimentalno prouchvane na vliianieto na vanadiia vurkhu enzimni pokazateli pri khronichno oralno vuzdeistvie.

Changes in selected enzyme parameters were followed in a one year-long toxicologic experiment on albino rat males given vanadium by mouth at either of two dosages: 0.005 mg/kg b.w., which is the equivalent of the regulated level for 1st category drinking water, or 0.01 mg/kg, i.e., twice the safety standard. The endpoints measured included: free sulfhydryl groups in blood serum, heart, and liver; cholinesterase and creatine kinase activities in blood serum; catalase activity in blood; and cytochrome oxidase activity in liver and heart. Chronic oral exposures to vanadium 0.01 mg/kg and, to a lesser extent, 0.005 mg/kg were observed to produce disturbances in redox processes and tissue respiration. The evidence from this study should be taken into consideration when regulating vanadium levels in drinking water from a hygiene standpoint.

[An experimental study of the atherogenic effect of vanadium in body uptake with drinking water]. / Eksperimentalno prouchvane vurkhu aterogenniia efekt na vanadiia pri postupvaneto mu v organizm s piteinite vodi.

During one year toxicological experiment on white male rats, receiving orally vanadium in doses 0.005 mg/kg, equivalent to the accepted in Bulgaria norm for ist category surface waters and 0.01 mg/kg, equivalent to the actually met in the drinking waters of some regions in this country heightened concentrations, its atherogenic effect is studied by indices: total cholesterol, beta-lipoproteins, phospholipid, lecithin, total lipids, total proteins, and hexoses of glycoprotein in blood serum; hydroxyproline, hexosamines, hexauronic acids and hexoses, connected with the proteins, in the aorta. A methodic approach is used for studying the atherogenic effect of vanadium on the processes of natural aging of the cardiovascular system. It is established that at chronic oral effect of the studied doses of vanadium no changes occur in the biochemical component of the connective tissue of the aorta and there are no infringements of the blood metabolism. In relation to the lipidic-only a decrease in the total cholesterol in the serum is established. The results show, that during the experiment vanadium causes no acceleration in the processes of natural aging of the blood vessels and has no atherogenic effect. Comparing the data for vanadium concentration in the drinking of Bulgaria to our results give grounds to reckon, that its heightened content in drinking waters of some regions presents no risk factor for the development of atherosclerosis.

[An experimental study of the atherogenic effect of the vanadium and nickel contained in drinking water when combined]. / Eksperimentalno prouchvane vurkhu aterogenniia efekt na vanadiia i nikela, sudurzhashti se v piteinite vodi, pri kombinirano deistvie.

During an annual toxicological experiment on white male rats, receiving orally vanadium (V) and nickel (Ni) in doses, equivalent to the accepted in Bulgaria, maximum allowable norms for ist category surface waters (respectively 0.005 mg/kg and 0.0025 mg/kg), 2 and 6 times and 20 and 60 times higher, is studied the atherogenic effect of the latter after the indices: total cholesterol, beta-lipoproteins, phospholipids, lecithin, total lipids, total protein and hexoses of glycoproteins in the serum; oxyproline, hexauranium acids and hexoses, hexosamines, connected with the proteins in the aorta. It is established that V and Ni in chronic combined effect in doses, equivalent to those accepted in Bulgaria, in maximum allowable concentrations for Ist category waters and surpassing them 2 and 6 time respectively, lead to no changes in the biochemical composition of the connective tissue of the aorta and to disorders in the lipidic and protein metabolism, while in higher doses is registered an increase of the glucoproteins and decrease in the glucosaminglycans in the aorta and decrease of the total lipids in the serum. The results point out, that V and Ni in the conditions of the experiment don't accelerate the processes of the natural ageing of the vessels and have no atherogenic effect. Juxtaposing the data for V and Ni concentrations in drinking waters in Bulgaria with our results give grounds to reckon, that their raised content in drinking waters in some regions do not represent a risk factor for the development of atherosclerosis.

[The effect of chronic combined exposure to nickel and lead on the enzymatic indices in body uptake with the drinking water]. / Vliianie na khronichnoto kombinirano vuzdeistvie s nikel i olovo vurkhu niakoi enzimni pokazateli pri postupvaneto im v organizm s piteinite vodi.

A toxicological experiment on white male rats was carried out for one year. They received simultaneously per os nickel in doses 0.005 mg/kg and lead in doses 0.0025 mg/kg, equivalent respectively to the recommended by CMEA norms for nickel and hygienic norm for lead in drinking waters, as well as nickel and lead in doses 0.015 and 0.01 mg/kg, 0.015 and 0.1 mg/kg surpassing 3 and 4 times and 30 and 40 times the above mentioned norms or only nickel in doses 0.015 mg/kg, after which their effect on some enzyme indices was studied. Tests were made on: free sulfhydryl groups in blood serum, heart and liver; catalase activity of blood; cholinesterase activity and creatinphosphatase in blood serum; cytochromoxidase activity in liver and heart. It is established that in combined per os effect of nickel and lead in doses respectively 0.15 and 0.1 mg/kg and 0.015 and 0.01 mg/kg, as well as during independent effect of nickel with doses 0.015 mg/kg, occur disorders in the tissue breathing and oxyreduction processes. Nickel and lead in doses, equivalent to the hygienic norms, lead to no changes according to all studied indices.

[Experimental data on the biological effect of nickel and lead contained in the drinking water acting in combination]. / Eksperimentalni danni za biologichniia efekt na nikela i olovoto, sudurzhashti se v piteinite vodi, pri kombinirano deistvie.

During one year toxicological experiment on white male rats, receiving simultaneously per os nickel in doses 0.005 mg/kg and lead in doses 0.0025 mg/kg, equivalent respectively to the recommended by CMEA norms for nickel and hygienic norm for lead in potable waters, as well as nickel and lead in doses 0.015 and 0.01 mg/kg. 0.15 and 0.1 mg/kg, surpassing 3 and 4 times and 30 and 40 times the norms or only nickel in doses 0.015 mg/kg, are studied for some sides of their biological effect. The following indices are examined: blood sugar lactatedehydrogenase, sodium, and potassium in the serum; haemoglobin, erythrocytes, reticulocytes and deltaaminlevulinatdehydrase activity in blood; glycoso-6-phosphatdehydrogenase in heart. It is already established, that in chronic combined oral influence with nickel and lead respectively in doses 0.15 and 0.1 mg/kg and 0.015 and 0.01 mg/kg is disturbed the carbohydrate metabolism, the electrolyte balance and the hemapoiesis, and in doses 0.005 and 0.0025 mg/kg no changes are established according to all examined indices. The nickel in doses 0.015 mg/kg at independent effect also leads to disturbance of the electrolyte, reticulocytic and erythrocytic metabolism.

[Physiological and hygienic studies of the thermal status of workers engaged in the manufacture of chocolate and other confectionary products]. / Fiziologichni i khigienni izsledvaniia v'rkhu toplinnogo sustoianie na rabotnitsi ot proizvodstva na shokoladovi i drugi sladkarski izdeliia.

Physiological-hygienic studies are performed on the thermal status of workers exposed to overheat microclimate in the production of chocolate and other confectionery, according to the following indices: temperature of the skin, perspiration, average temperature of the body and pulse. It is already established that the microclimate discomfort leads to stress of the thermoregulating mechanisms. Recommendations are given for improving the work conditions concerning the microclimatic factor.

[The biological effect of copper taken up by the body via drinking water]. / Vurkhu niakoi strani na biologichniia efekt na medta pri postupvaneto ì v organizma s piteinite vodi.

A one-year toxicological experiment is carried out on albino male rats, receiving orally copper in doses 0.01, 0.1 and 1 mg/kg, respectively equivalent to the sanitary norm for drinking waters and 10 and 100 times above the latter are studied some aspects of the biological effect of copper according to the indices: total protein in blood serum, potassium and sodium in blood serum and heart, vitamin C and adenosinetriphosphate in blood. It is established that the chronic intoxication with copper in doses 1 and 0.1 mg/kg leads to the disturbance of electrolyte exchange in the organism and to changes in the level of vitamin C in blood, in doses 1 mg/kg--to disturbance of the protein exchange, and in doses 0.01 mg/kg no changes are established in all examined indices.

[Toxic action of nickel when taken up by the body from the drinking water]. / Vurkhu niakoi strani ot toksichnoto deistvie na nikela pri postupvaneto mu v organizma s piteinite vody.

Some aspects of the toxic effects of nickel were studied in a toxicological experiment for one year on male albino rats, administered perorally nickel in doses 0.0005, 0.005, 0.05 and 0.5 mg/kg, corresponding to 1/10 of the Soviet MAC respectively, MAC, 10 MAC and 100 MAC of nickel in potable waters, by the following indices: behaviour and general condition of the animals, body weight, weight coefficient of organs; total protein, blood sugar, glucose-6-phosphate dehydrogenase and lactate-dehydrogenase on serum; hemoglobin and erythrocytes in blood. The chronic nickel intoxication in doses of 0.5 mg/kg was established to lead to disorders in protein metabolism and reduction of body weight, in doses of 0.005, 0.05 and 0.5 mg/kg--to disorders in carbohydrate metabolism, erythrocytosis and hyperhemoglobinemia, and in doses of 0.0005 mg/kg--no changes have been established as regards all indices studied.

[Air environment conditions in the patients' rooms of multistory hospitals]. / Prouchvane usloviiata na vuzdushnata sreda v bolnichnite stai v mnogoetazhni bolnitsi.

Air conditions, in winter and summer, were studied in 4 hospital rooms of the multistorey Institute of Obstetrics and Gynaecology, Medical Academy - Sofia. The studies were carried out in the following principal directions: I) Chemical pollution of air; 2) Microbic contamination; 3)Physical state of the environment; 4) Physiological examinations of 52 afebrile patients. The air in the hospital rooms depends on season, storey, cubage, heating regime, airing and maintaining, expressed by various indices. The state of the patients examined according to some principal physiological indices is adequate to the physical components of the environment.