1. The hydrazine mustard spin label (HMSL), recently synthesized in our laboratory (Raikova, 1977) was used for spin-labelling of DNA. 2. It alkylates both double- and single-stranded DNAs. 3. The reaction of HMSL with DNA was studied with respect to the kinetics of alkylation, dependence on salt concentration and base specificity. 4. It was found that HMSL is a base-specific reagent, alkylating preferentially guanine. According to their ability to bind HMSL, the four deoxyribonucleotides are ordered in the following way: G greater than A greater than C greater than T. 5. The EPR spectra obtained strongly depended on the secondary structure of the spin-labelled DNA: unlike the immobilized spectra of the double-stranded DNAs (2AZZ = 44.8G), the EPR spectra of single-stranded DNAs were non-immobilized (2AZZ = 32.8 G). 6. When sheared double-stranded DNA was spin-labelled, the parameters of the EPR spectrum depended also on the GC content of DNA.

Animals↗

PubMed1982

[Decarboxylase and hemolytic activity in Listeria].

Investigated were a great number of Listeria monocytogenes strains of 1/2a, 4b, 5, and 6 serotypes for the production of decarboxilase, hemolysin, and pathogenicity for albino mice. It was found that only representatives of 1/2a serotype (40 out of 93 studied strains) produced decarboxilase for glutamic acid. The hemolytic activity was evaluated by means of a Spekol after the hemolysis of sheep erythrocytes. A correlation was established between hemolytic activity and pathogenicity, consisting in that albino mice were killed in a higher percent by strains that showed higher hemolytic activity.

Animals↗

PubMed1982

[Method of controlling live vaccines against listeriosis].

Used was Anton's conjunctival test with guinea pigs to control the actual immunogenicity and innocuity of a live vaccine against listeriosis. It was found that local immunity could be produced following a successive conjunctival infection only, initially with the use of a listeriosis vaccine and in not less than ten days later with pathogenic strains of the respective serotype. The method makes it possible to carry out both titration and control on the equal volume ratio of the vaccinal strains of the two serotypes in the vaccine.

Animals↗

PubMed1982

[Protein-carbohydrate ratio in the diet and its effect on digestive processes in sheep].

Four experimental periods were followed up with fistulated sheep. During each period the animals were offered rations of different protein and carbohydrate ration. Experiments were also carried out to elucidate the physiology of the digestive processes, and the resorption and metabolism of the various nutrients. It was established that digestive and metabolic processes ran a best course at the protein to carbohydrate ration of 1:5.8. At 1:10 and 1:14.5% a carbohydrate depression set in which led to a certain drop of the coefficients of digestibility. The body was forced to excrete higher amounts of digestive juices with a higher content of organic mineral matter in the duodenal chyme. The digestive apparatus was said to be subjected to substantial stress during the conversion of the various feeds and their components into nutrients that were characteristic of the organism, their ratio being thoroughly different in principle in the feeds and in the animals body. Conversion was shown to start not in the blood and tissues but in the digestive tract.

Animal Feed↗

PubMed1982

[Respiratory diseases in sheep due to Mycoplasma ovipneumoniae].

Mycoplasma ovipneumoniae was isolated from sheep and lambs affected with a respiratory disease. It was established that the pneumonic disease caused by this organism was a severe one, with high mortality rate in young lambs. Adult sheep and older lambs remained chronically affected. Susceptibility varied, depending on the breed of the animals, some imported animals running a more severe course of the disease than the local ones. The disease was artificially induced in lambs at the joint infection with M. ovipneumoniae and P. haemolytica. The morphologic changes in the lungs consisted in a prevailing proliferation of the septal cells and polynuclear cells in the alveoli, an interseptal histiocyte proliferation, and a serous leukocyte infiltration.

Animals↗

PubMed1981

Chemical burns of the esophagus in children.

Explore the source record for details and available documents.

Adolescent↗

PubMed1981

[Embryotropic action of the triazine herbicide polyzin 50].

The embryotropic effect of the new Bulgarian simtriazine herbicide polyzin 50 was studied in an experiment upon 90 pregnant albino rats - Wistar, via inhalation effect in concentrations 2 mg/m3 and 0.2 mg/m3, daily during the whole pregnancy and at a level of 2 mg/m3 during the first trimester of gestation. With both regimes, the preparation has a teratogenic and a more lightly manifested embryotoxic activity. In the absence of general toxic effect upon the pregnant organism, polyzin induces external malformations (hypognathus, oedema), anomalies in the development of the internal organs (hydrocephalus, intracerebral hematoma, hemorrhages in the abdominal cavity, infarctus-like foci in liver) and defects in the ossification of the cranial bones of fetus. The preparation has an embryotoxic activity (increased incidence of subcutaneous hematomas of the fetus), only with the daily penetration in organism of the pregnant animals in a concentration of 2 mg/m3. With both concentrations of antenatal effect of polyzin studied, a functional insufficiency of the liver of the progeny develops during the postnatal development period. On the grounds of the data obtained about the embryotoxic and teratogenic effect of polyzin with its inhalation effect in low concentrations - 2 mg/m3 and 0.2 mg/m3, a recommendation is proposed-prohibition of women's participation in its production at a fertile age.

Animals↗

PubMed1981

[Biorhythm changes in DNA synthesis in hepatocytes exposed to organophosphates and strontium-89].

The authors irradiated albino rats with I microc/gr strontium89 with previously modelled liver injury by FOS (Agria 1050). A temporary inhibition of the methodical activity was established as well as aberrant mitoses and strongly manifested polyploidity of the hepatic cells. Those phenomena faded quickly (within 8 days), with the exception of polyploidity, which as a sign of physiological regeneration the authors admit to be adaptive reaction directed to the restoration of the functional level of the liver on account of the hepatocytes preserved. Prior to the onset of tissue regeneration, the cellular one should be terminated, due to which, the mytotic activity was highly inhibited on the 3rd day of the irradiation, the DNA-synthesis cycle being lengthened and mainly on account of tgi, i.e. during the reparative biosynthesis the cell is incapable/of developing in the mitotic phase. After the presynthetic period is over the hepatocytes rapidly overcome the inhibition, tgi is considerably shortened and from presynthesis they almost immediately enter the period of mitosis. That requires an additional protein synthesis, manifested by the changes in serum protein. S and G1 proved to be most sensitive to DNA-synthesis blocking. The presynthetic period is essentially lengthened due to lesions of the cellular structures, synthesizing substances, necessary for entering S - i.e. the hepatocytes pass T, equal to the inhibition between G1 and S, its duration being proportional to the degree of the lesion of the organ.

Animals↗

PubMed1981

[Liver diseases and their relationship to forestomach function in highly productive cows].

Studied were 12 cows with protracted, recurrent acidosis of the rumen, 4 cows with alkalosis, and 2 calves with experimental acidosis, following up the changes in the rumen content and their impact on the liver. The diseased animals were investigated both clinically and by laboratory tests with regard to alkaline phosphatase, plasma cholinesterase, SGOT, SGPT, alkali reserves, bilirubin, blood sugar, protein function of the liver (flocculation tests), biopsy of the liver, urine pH, urobilinogen, sedimentation test and ketone bodies, rumen pH, rumen infusoria, glucose-fermenting and cellulose-digesting activity, breakdown of nitrates, butyric acid, and ammonia gas. It was found that recurrent physiologic deviations of the rumen content play an essential pathogenetic role in liver injury. The more substantial and continuous the deviations the more severe the liver diseases. Studies revealed that along with other factors the recurrent acidosis and alkalosis of the rumen content could be claimed to be an immediate cause of the liver diseases in high producing cows. Histologically, the liver of cows with slightly expressed acidosis of the rumen showed granular degeneration, and of cows with protracted acidosis--fatty degeneration, activation of the reticulo-endothelial system, and leukocytes in the capillar sinusoids. Liver biopsy in the case of experimental acidosis demonstrated also decrease in the glycogen content of the hepatocytes.

Acidosis↗

PubMed1980

Neoplastic growths in chickens treated with cell and cell-free material from transplantable hepatoma induced by virus strain MC-29.

Series of experiments were carried out with chickens (line 15-I and Canadian white leghorn) for establishing the oncogenic properties of Mc-29 virus strain after its multiple replication in cells transformed by it (hepatoma cells). It was established that: 1. After s. c. and i. m. inoculation of intact hepatoma cells local hepatomas of varying size developed after 8--15 days accompanied with general viremia; after i. p. or i. v. injection multiple hepatoma growths occurred in the visceral organs and bone marrow. 2. The i. v. or i. p. inoculation of cell-free material of hepatoma or blood plasma of hepatoma bearing chicken lead after 48--80 days to the formation of hemocytoblastic and myelocytoma growths in the visceral organs and in the bone marrow and exclusively rare--of primary liver and kidney carcinomas. After s. c. injection of cell-free material the result is negative. A conclusion could be drawn that strain Mc-29 virus though replicated in the transformed hepatoma cells preserved its basic leukemogenic potentialities to induce myelocytomatosis and hemocytoblastosis and very rarely--liver and kidney carcinomas.

Age Factors↗

PubMed1980

[Allergic skin reaction in infectious rhinotracheitis and infectious pustular vulvovaginitis in cattle].

Through a skin-allergic reaction were subjected to a study cattle of different ages (calves-sucklings, growing calves and grown up calves), originating from 4 different from the epizootic point of view cow-farms--one latent focus, two foci with an apparent infection and one cow-farm in good health conditions. On the healthy cow-farm the skin-allergic reaction and the virus neutralizing reaction were not marked. On the farms affected with latent infection and with manifestation of abortions with cows, the skin-allergic reaction with calves till the age of 3 months was negative, whereas the virus neutralizing reaction was usually positive; with the calves at the age of about 6 months the skin-allergic reaction began slightly to become positive. The virus neutralizing reaction was also positive. With the grown up animals both reactions were positive. In the development of recently brought clinical infection among the calves, without affecting their mothers, both reactions were negative with newly born calves, whereas from the second month onward, they began to become positive.

Animals↗

PubMed1980

[2 new tests for diagnosing traumatic reticuloperitonitis in cattle].

Two new samples for diagnosing a strange-body illness in cattle were proved. Along with the use of other means for diagnosing a strange body, the elaborated new samples provide a greater precision for determining the size and position of the strange body. A description of the structure of the apparatus is given, as well as the manipulation with it in and out of the animal's body. Ferroscopy and röntgenography will help the specialist to prove the strange-body illness in cattle and thereby the means known so far for diagnosing the traumatic reticuloperitonitis become more complete. These two methods combined together could have a large practical application.

Animals↗

PubMed1978

"Maturation" of DNA duplexes.

Reassociation of typical single-copy DNAs, like E. coli DNA, even when performed at relatively low temperatures, results in the formation of perfect duplexes with thermal stability very close to that of the native DNA. In contrast, duplexes of mouse repeated DNA as well as duplexes of Streptomyces DNA prepared under the same conditions, show a low thermal stability and undergo post-reassociation changes upon prolonged incubation. These changes, called "maturation" of the DNA duplexes, result in increasing of their thermal stability. Some of the factors affecting the rate of "maturation" are studied. The implication of the "maturation" process in reassociation analysis and in characterization of the heterogeneity of DNA is discussed.

Animals↗