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Biomedical subjects

M G Iogannsen

Publications and source records attributed to M G Iogannsen.

At least 19 recordsLinked to original sources
PubMed1998

[A model of rat's urinary bladder tumor induced by subcutaneous injection of N-butyl-N-(4-hydroxybutyl)-nitrosamine].

A model of urinary bladder tumor was developed in the rat by subcutaneous injection of N-dibutyl-N-(4-hydroxybutyl) nitrosamine. A direct dose-tumor frequency correlation was established. Maximum effect (100%) was recorded with administration of 70 mg of the carcinogenic agent twice a week, for 3 months. Among neoplasms induced were transitional-cell and in situ carcinoma, and multiple papilloma of the bladder. Carcinogenesis was found to involve a significant rise in the activity of urinary beta-gluco-uronidase which may be used as a diagnostic testing procedure.

Animals↗
PubMed1991

[Features of peroxidase oxidation of amidopyrine and its analogs].

Peroxidatic oxidation of N-alkyl and sulfalkyl-substituted 4-aminopyrazolones (amidopyrine and metapyrine) is mediated by oxyperoxidase, whereas the oxidation of non-substituted 4-aminoantipyrine occurs via the classical peroxidase cycle, without oxyperoxidase accumulation. The free radicals formed at the first step of the oxidation cycle show a tendency for disproportionation and exchange. During catalysis in heavy water the oxidation of substituted aminopyrazolones is accelerated by plant peroxidase. This effect is due to the activation of the second oxidative state of the enzyme. Complete peroxidatic oxidation of amidopyrine results in the formation of several reaction products. The main product is not identified as dioxypyramidone formed via nonenzymatic peroxidatic oxidation. The oxidation of the indicator (azopyram) which represents an amidopyrine-aniline mixture results first in the formation of amidopyrine radicals. The reaction product (dye) is formed via the binding of these radicals to aniline radicals. The latter are predominantly formed via a nonenzymatic route during the reduction of the amidopyrine radicals by aniline. Similar to the formation of azopyram and the full oxidation of amidopyrine, this reaction is accompanied by the displacement of the substituents from the 4-amino group.

Aminopyrine↗
PubMed1990

[An aniline method of determining glucose in biological fluids].

A simple method for glucose measurements in biologic fluids has been developed, making use of aniline chromogen. Using this method, one may do without carcinogenic ortho-toluidine and work with less concentrated (and less acid) acetic acid solutions. Introduction of the aniline method of glucose measurement will help improve the working conditions of laboratory assistants at laboratories employing the ortho-toluidine method at present.

Aniline Compounds↗
PubMed1989

Tissue specificity of nucleo-cytoplasmic distribution of HMG1 and HMG2 proteins and their probable functions.

The levels and distribution between nucleus and cytoplasm of HMG1 and HMG2 proteins have been investigated in different tissues of mammals. In lymphoid tissues and testis high amounts of these proteins are present in both nuclei and cytoplasm, while in the hepatic tissues and brain they accumulate in cytoplasm, mainly in the cytosol. In particular, very low amounts, if any, of HMG1 and 2 are present in the nuclei active for DNA replication (rat regenerating liver and primary hepatoma) or transcription (adult liver and brain). Therefore, it appears that HMG1 and 2 are not necessary for these processes. On the other hand, nuclear (chromosomal) HMG1 and 2 are characteristic for the tissues containing undifferentiated cells: lymphoid tissues, testis, neonatal liver. These proteins are bound to the chromatin regions solubilized early by sonication or DNase action. Comparison of the data obtained for different tissues shows an inverse correlation between the amounts of chromosomal HMG1 and 2, on the one hand, and of histone H1(0), on the other hand. These results suggest that chromosomal HMG1 and 2 take part in the processes that occur during cell differentiation, while histone H1(0) is induced to preserve differentiated cells from dedifferentiation.

Animals↗
PubMed1988

[Spontaneous tumors in rats bred at the N.N. Petrov Research Institute of Oncology of the USSR Ministry of Health].

The paper discusses spontaneous tumor profile in albino rats bred at the N. N. Petrov Research Institute of Oncology of the USSR Ministry of Health (1981-1984). The overall incidence of tumors and that of malignant ones were shown to be 27.2 and 12.5%, respectively, in males and 47.4 and 16.4%, respectively, in females. Pituitary and hemopoietic tumors most frequently occurred in males (67%). Female rats most often revealed tumors of the pituitary, breast and hemopoietic system (90%). On the whole, the tumor profile proved identical in the animal population studied and that of Rappolovo farm of the USSR Academy of Medical Sciences. However, infection resistance in the former population was superior.

Animals↗
PubMed1983

[Oncological characteristics of CC57BR mice].

The oncologic and non-oncologic morbidity in intact CC57BR mice was studied over a period of 1978-1980. Tumors occurred in 23.5%, while malignant tumors were in 14.3% of mice. Benign adenomas of lung were the most frequent 10.9%. Malignant tumors included generalized reticulosarcomatosis and leukemia 6.8%, cancer of the skin 3.4% and single different tumors. Pneumonia and enteritis were the most frequent among non-oncologic diseases. Since CC57BR mice belong to a low cancer line, they should be used for various long-term cancer and non-cancer experiments.

Adenoma↗
PubMed1983

[Effect of carcinogenic 2-naphthylamine on organ cultures of the urinary bladder of the rat].

Treatment with 2-naphthylamine was followed by an 1.5-3 fold increase in the frequency of hyperplastic changes in the organ culture cells of rat urinary bladder epithelium, as compared with intact control and cell cultures treated with a non-carcinogenic analog (30.8, 17.6 and 10.7%, respectively). It is suggested that this effect was associated with the initial specific blastogenic effect of 2-naphthylamine metabolites on rat urothelium, the latter being traditionally considered resistant to this agent. Some other factors absent in rats but present in humans and dogs are indispensable for further malignant transformation and tumorigenesis.

1-Naphthylamine↗
PubMed1982

[Oncologic properties of non-inbred white rats raised at the Petrov Research Institute of the Ministry of Health of the USSR].

The paper discusses the incidence of spontaneous tumors and general morbidity in albino noninbred rats raised at the N. N. Petrov Research Institute of Oncology of the USSR Ministry of Health and used in different chronic experiments. It was found that spontaneous tumors occur, on the average, in 25.7 and malignancies--in 6.2%. Infectious hemorrhagic pneumonia and gastroenteritis (acute capillary toxicosis) are relatively infrequent. The general morbidity patterns in these rats are similar to those in Wistar line, the essential difference being a lower frequency of tumors of the medullar layer of adrenals. Hence, the rats bred at the Institute may be successfully used in various chronic experiments, including those associated with carcinogenic studies.

Animals↗
PubMed1980

[Systemic blood diseases in inbred mouse strain CC57W].

In "low cancer" CC57W mouse line studied over a period of 1944--1969 spontaneous leukemias occurred in 0.4--6.8%. During 1971--1976 the frequency of spontaneous leukemias amounted to 33%. Morbid anatomic and hematologic studies showed that aleukemic and subleukemic forms of chronic generalized reticulosarcomatosis with predominant affection of the lymphatic system accounted for the overwhelming majority of systemic diseases of the blood. Electron microscopy revealed virus-like type C particles in the cells of the affected organs.

Animals↗
PubMed1980

[Potential oncogenic action of the RNA isolated from rat lymphosarcoma].

From the tissue of the transplantable strain of rat lymphosarcoma, using phenol technics, a total RNA (sedimentation constants 31,5S; 19,0S; 6S) and chromosome-nuclear mRNA were isolated. The preparations contained up to 10% of protein. Nucleic acids (in a dosage of 10 mg RNA) were given by single intraperitoneal injections to 2 month-old rats. The animals showed a 180% increase of the lymphatic neoplasms yield when injected both total RNA and mRNA. Transplantation into newborn rats of the rat lymphocytes, treated in vitro by the total RNA preparations, failed to yield such a significant increase in the occurrence of neoplasms. A molecular weight of RNA fragments was similar to that in the experiments on transfection by nucleic acids, isolated from tumors of viral etiology.

3,3'-Dichlorobenzidine↗
PubMed1977

[Several structural characteristics of vital dyes].

Lymphocytes and macrophages of normal rats, cells of lymphosarcoma and ovarian carcinoma of rats (CC strain), cells of sarcoma 37 and lymphosarcoma Nk/Ly of mice were investigated for their capacity for vital staining by 86 days in concentrations within the range of 10(-5)--3-10(-2) M. It was found that alkylation of amino groups of the basic dyes increased their capacity for penetrating the living cells and depositing in their cytoplasm in cases of thiazine, oxazine, acridine, xanthene, diazine, and triphenylmethane compounds. The acid radicals decreased the capacity of the dye to vital staining of the cells considerably. The degree of basicity of the dye molecule and its amino groups played no decisive role in the process of vital staining.

Animals↗
PubMed1976

[Urinary bladder organ culture with a continuous nutrient system].

A system of flowing nutrition for organic cultures has been developed with possible observation of explants at small magnifications of microscope. The nutrient fluid circulates by the gravity. The proposed method permits sustaining the vital capacity of explants of the urinary bladder mucosa of young rats with reservation of characteristic organotypical structures and phenomena of the epithelium proliferation as long as 7 weeks. The described method may be used when modelling different pathological processes in tissues.

Animals↗