Cloning of Lewis lung carcinoma cells in agar cultures in diffusion chambers

A method was developed for cloning the Lewis lung carcinoma cells (LLC) in vivo in diffusion chambers. This method is analogous to the system introduced by Gordon for cloning hemopoietic precursor cells. No significant differences were observed in the efficiency of the cloning of the tumour cells within the range of 1 to 4 weeks after transplantation (7.7 +/- 0.7% for 240 cultures).     

Endothelial changes in the pulmonary blood vessels of mice with Lewis lung carcinoma and experimental stress

The influence of surgical tumour removal and of the emotional-pain stress described by Desiderato on the lung metastases development and lung vascular internal surface state was studied in C57BL mice with Lewis carcinoma. Scanning electron microscopy revealed a stress-damaging effect on vascular walls. It is possible to assume that the stress damage of pulmonary blood vessels greatly influences the stimulation of metastases. Concrete mechanisms responsible for this phenomenon are elucidated.     

Autoradiographic study of the proliferative activity of bone marrow, spleen and liver cells in healthy mice and in mice with Rauscher virus-induced erythroleukemia

Bone marrow, spleen and liver of healthy and erythroleukemic mice have been studied by autoradiography. A peripheral zone, where the most of cells were involved in mitosis, and a central one, where the mitotic index was lower, were established in the bone marrow. Normally a zone of high proliferative activity was found in the subcapsular region of the spleen. Boundaries of such zones in the bone marrow and spleen of erythroleukemic mice disappeared. Most of the cells forming the leukemia infiltrates in the liver are in the phase of DNA-synthesis.     

The components of the blood plasma fibrinolytic system in mice with Lewis lung carcinoma

The fibrinolysis system components of the circulating blood plasma have been studied in experiments on C57Bl/6 mice in the dynamics of growth and metastasis of the Lewis lung carcinoma. It has been shown that a growth and metastasis of malignant tumours are accompanied by the fibrinolysis activity inhibition. Changes in the fibrinolysis processes are observed already on the 3rd day after tumour inoculation. These changes increased in the course of the tumour growth progress.     

Detection of chalones produced by a primary tumor in the blood of mice with Lewis carcinoma

The substance fraction precipitated in 81% ethanol from blood or tumour tissue of mice with Lewis (3LL) carcinoma on the 13th, 20th and 32nd day after the tumour transplantation is established to inhibit the processes of proliferation in the cell culture of the same tumour. The fraction isolated on the 7th day after transplantation stimulated the proliferation. No inhibition of proliferation was observed when studying the effect of the same fraction isolated on the 13th and 20th day from blood of mice with B-16 melanoma on the 3LL carcinoma. This fact suggests a tissue-specific action of proliferation inhibitors isolated from blood of mice with Lewis 3LL carcinoma and permits considering them as chalones. An assumption is advanced that the primary tumour synthesizing chalones and secreting them into blood can regulate not only its own growth but also the growth of remoted metastases.     

Distribution kinetics and metabolism of triiodothyronine and thyroxine in the organs and tissues of mice with transplanted Lewis carcinoma

A comparative analysis of triiodothyronine (T3) and thyroxine (T4) distribution in organs and tissues of tumour-bearing and intact mice conducted wih 125J labelled T3 and T4 has shown considerable differences in the accumulation character of these hormones in mice with Lewis carcinoma and in intact animals in the liver, kidneys, lungs, adrenal glands, lymphatic nodes. Low T3 and T4 concentration in the blood of tumour-bearing mice was observed during the whole period of study.     

Effects of constant magnetic field on the growth and metastasizing of Lewis carcinoma in mice

In mice with the metastasizing Lewis carcinoma the constant magnetic field (CMF) was studied for its effect on growth and metastatic process depending on the immobilization of animals. The results obtained show a decrease in the rate of the primary tumour growth and in the intensity of the metastatic process under the influence of CMF by incomplete immobilization. Complete immobilization eliminates the antimetastatic effects of the CMF.     

Normalizing effect of interferon on the system of mixed-function oxidases in the liver of mice with Lewis lung carcinoma

The effect of interferon (IF) on the activity of multipurpose hepatic oxidases (MHO) in animals in the process of metastatic tumour development as well as interaction of IF and vinblastine (VBL) in the cell culture have been studied. IF activates MHO under conditions of their inhibition at the beginning of the tumour development and inhibits them to the normal level under activation in the postmetastatic period. Contrary to the data obtained in vivo IF does not decrease the toxicity of VBL for the tumour cells in vitro. The data obtained evidence for the modulating effect of IF on the MHO system under the tumour development.     

Effect of splenic cells sensitized with staphylococcal enterotoxin A on the metastasis of Lewis lung carcinoma in mice

The effect of intact mouse spleen cells sensitized in vitro with staphylococcus aureus enterotoxin A (SEA) on spreading of mouse Lewis carcinoma was studied. A significant decrease in a number of metastases in the lungs and in the weight of the lungs was observed after multiple intrapulmonary inoculation of spleen cells treated with SEA for 6 hours. The effect was less marked after inoculation of the sensitized cells intraperitoneally or into the femoral muscle of the leg affected with the tumour. After multiple inoculations of the sensitized cells, the spleen cells of the treated animals develop the state of interferon hyporeactivity to SEA but not to PHA or NDV.     

Modifying effect of IgE hyperproduction on the proliferative response of lymphocytes from intact mice and mice with transplanted tumors

It is shown that under conditions of IgE-induced reaction the tumour growth is altered, which may be explained by different degree of expression of functional activities of immunocompetent cells in mice with transplanted tumours and marked immediate-type reaction. Changes in the immunological state manifest in stimulation of the proliferative response primarily to B-cell mitogens under conditions of increased synthesis of IgE, which permits suggesting that under these conditions B-cells play an important role in antitumour immunity.     

Suppressor activity of bone marrow and spleen cells in C57Bl/6 mice during carcinogenesis induced by 7,12-dimethylbenz(a)anthracene

The nonspecific suppressor activity of bone marrow cells (BMC) and spleen cells (SC) of C57B1/6 mice was studied at 7,12-dimethylbenz(a)anthracene-induced carcinogenesis. It is established that in the latent period of the tumour development and with its appearance the suppressor activity of BMC decreases, while SC-increases. The activity of the BMC suppressor factor which is determined by the inhibition of proliferation of mastocytoma P-815 cells in vitro did not change significantly.     

Inhibition of the metastasis of Lewis lung carcinoma in mice by the administration of spasmolytin, midantan and L-DOPA

Different combinations and doses of neurotropic drugs of the central action (spasmolytine, midantane, L-DOPA) coupled with the surgical removal of the lung Lewis carcinoma were studied for their effect on the metastatic spreading in C57BL/6 mice. It has been established that the long-term use of spasmolytine and midantane before and after the operation inhibits the metastatic process, that is expressed in the total volume reduction of lung metastases, lack of metastases in a number of mice and augmentation of the average life. Such method of drug application is more effective in the metastatic growth inhibition as against their application only in the pre- or postoperation periods as well as with the use of the other neurotropic drug combinations.     

Effects of prostaglandins E2 and F2 alpha on the hypothalamo-hypophyseal-adrenal system and thyroid function in mice with Lewis lung carcinoma

It has been determined that prostaglandins E2 and F2 alpha being exogenously inoculated during the premetastatic period to mice with metastatic Lewis lung carcinoma in equal degree activate neurocytes of supraoptic and paraventricular hypothalamus nuclei, playing the important role in secretion of peptidergic hypophysial adrenal gland complex, but they exert unequal influence on pituitary body, adrenal cortex and thyroid apparatus. F2 alpha stimulates the pituitary body corticotrophic function, secretory function of spongiocytes and thyrocytes, identifies the thyroxin and triiodothyronine utilization, E2, on the contrary, does not influence these indices or reduces them. Obviously, the mentioned above differences between E2 and F2 alpha may be explained by their different influences on antimetastatic resistance.     

The enhancement under the action of a limited diet of the antimetastatic effect due to macrophage activation in mice with Lewis carcinoma

An antimetastatic effect associated with macrophage activation by liposome-encapsulated glucosaminylmuramyldipeptide was found to enhance in malnourished mice with the Lewis lung carcinoma. These changes were not matched by further increase in the functional activity of macrophages. It has been suggested that enhancement of the antimetastatic effect in malnourished animals is due to the inhibition of neovascularization necessary for the beginning of metastatic exponential growth. The induction of neovascularization may be caused by the tumor necrosis factor, main product of activated macrophages.     

The effect of emotional-pain stress syndrome on the biochemical characteristics of the stress-realizing system and metastasis of Lewis lung carcinoma in mice

The emotional-pain stress (EPS) in C57BL mice with Lewis carcinoma was studied for its influence on serotoninergic, noradrenergic, dopaminergic, glutamatergic, aspartatergic, glycinergic, taurinergic, GABA-ergic and cholinergic mediator mechanisms of the hypothalamus, the level of corticotropin, free and bound 11-corticosteroids, insulin, thyroxin and testosterone in blood plasma as well as on the content of catecholamines, their precursors and catabolites in urine. EPS contributed to a long-term activation of stress-realizing systems resulting in generalization of decompensation in them. The stimulating effect of EPS on the incidence and growth of metastases is established depending on the terms of its application.     

Effect of bleomycetin on the proliferative activity of bone marrow and lymph node cells in SJL/J mice

Dynamics of dose and time dependence of bleomycin action on bone marrow and lymph node cells of SJL/J mice has shown that 6 h after administration of 25 micrograms of bleomycin the proliferative activity is 1.5 times reduced. The antibiotic influences the interphase cells and delays a cellular cycle. A durable and persistent decrease of the proliferative activity (up to 10 days) of bone marrow and lymph node cells shows a prolonged action of the bleomycin single dose and a pronounced cytostatic effect of the antibiotic on cellular elements of SJL/J mice. Bleomycetin is established to produce action both on lymph node and bone marrow tumour cells of SJL/J mice.     

A model for the formation of donor centers in silicon layers implanted with erbium and oxygen ions

Formation of donor centers in the course of annealing of layers of single-crystal silicon FZ-Si (grown by the float-zone method) and Cz-Si (grown by the Czochralski method) implanted with Er⁺ and O⁺ ions was simulated. The diffusion-kinetics equations accounting for the formation of erbium-related donor centers of three types were solved numerically. These centers were formed with the involvement of oxygen in the substrate or implanted oxygen and also self-interstitials I produced during annealing of implantation-induced defects; i.e., the Er-I, Er-O, and Er-O-I centers were considered. The results of calculations satisfactorily describe the concentration profiles of donor centers and also the influence of oxygen in the substrate and implanted oxygen on the dependence of the donor-activation coefficient of erbium on the annealing temperature in the range of 600–1200°C.     

The influence of oxygen on the formation of donor centers in silicon layers implanted with erbium and oxygen ions

A model of the formation of donor centers introduced by a combined implantation of Er⁺ and O⁺ ions into silicon with subsequent thermal annealing is developed. These centers are multiparticle erbium-oxygen complexes ErO_n with n≥4. The competing process of formation of electrically inactive oxygen clusters is taken into account. The model makes it possible to describe the dependence of the activation coefficient for the donor centers on the implantation dose of oxygen ions and, also, the effects of the oxygen ion implantation and annealing temperature on the concentration profiles of the donor centers.