Liquid Fraction Effect on Foam Flow through a Local Obstacle.

An experimental study of quasi-two-dimensional liquid foams with varying liquid fractions is presented. Experiments are conducted in a Hele-Shaw cell with a local permeable obstacle placed in the center and filling 35, 60 and 78% of the cell gap. Foam velocity is calculated using a standard cross-correlation algorithm.

The characteristics of impaired functions and life limitations of disabled people due to coronary heart disease.

The article presents the characteristics of the impaired functions and life limitations of disabled individuals due to coronary heart disease, considering the clinical data, the disease stages, and the disability severity. It was revealed that the largest share in the structure of impaired functions was made up by the impaired functions of the cardiovascular neuromuscular, movement-related (statodynamic), endocrine systems and metabolism and life limitations of I, II and III degrees related to self-care, movement and labor activity.

Relationship between radioadaptive response and individual radiosensitivity to low doses of gamma radiation: an extended study of chromosome damage in blood lymphocytes of three donors.

Purpose: Our study aimed at evaluating: 1) whether well-established variability in radioadaptive response (AR) in various donor blood lymphocytes might be attributed to inter-individual differences in radiosensitivity to different low dose levels; 2) whether AR is reproducibly present over time in the lymphocytes of AR-positive individuals. Experimental procedure: Whole blood samples of three donors were exposed to low doses (2-30 cGy) of γ-radiation alone (G phase) or followed by a 1 Gy challenge dose (late S/early G phase), and chromosome aberration were scored to assess the dose-response relationship and adaptive response, correspondingly. Three experiments were performed on blood samples of the same donors at six month intervals.

Modeling cell response to low doses of photon irradiation: Part 2--application to radiation-induced chromosomal aberrations in human carcinoma cells.

The biological phenomena observed at low doses of ionizing radiation (adaptive response, bystander effects, genomic instability, etc.) are still not well understood. While at high irradiation doses, cellular death may be directly linked to DNA damage, at low doses, other cellular structures may be involved in what are known as non-(DNA)-targeted effects.

Modeling cell response to low doses of photon irradiation--Part 1: on the origin of fluctuations.

Intra- and inter-individual variability is a well-known aspect of biological responses of cells observed at low doses of radiation, whichever the phenomenon considered (adaptive response, bystander effects, genomic instability, etc.). There is growing evidence that low-dose phenomena are related to cell mechanisms other than DNA damage and misrepair, meaning that other cellular structures may play a crucial role.

Cytogenetic effects of low-dose radiation with different LET in human peripheral blood lymphocytes.

Chromosome damage and the spectrum of aberrations induced by low doses of gamma-irradiation, X-rays and accelerated carbon ions (195 MeV/u, LET 16.6 keV/microm) in peripheral blood lymphocytes of four donors were studied. G0-lymphocytes were exposed to 1-100 cGy, stimulated by PHA, and analyzed for chromosome aberrations at 48 h post-irradiation by the metaphase method.

[Induction of chromosome aberrations and micronuclei in human peripheral blood lymphocytes at low dose of radiation].

The chromosome damage induced by the doses of y-irradiation 6)Co in peripheral blood lymphocytes was studied using different cytogenetic assays. Isolated lymphocytes were exposed to 0.01-1.

[Cytogenetic effects of low dose radiation with different LET in human peripheral blood lymphocytes and possible mechanisms of their realization].

The induction of chromosome damage by the exposure to low doses of gamma-(60)Co and accelerated carbon ions 12C in peripheral blood lymphocytes of different donors was investigated. The complex nonlinear dose-effect dependence at the range from 1 to 50-70 cGy was observed. At the doses of 1-5 cGy the cells show the highest radiosensitivity (hypersensitivity), mainly due to the chromatid-type aberration, which is typical to those spontaneously generated in the cell and believed not to be induced by the irradiation of unstimulated lymphocytes according to the classical theory of aberration formation.

Chromosome instability of HPRT-mutant subclones induced by ionising radiation of various LET.

The induction of HPRT-mutations and survival of Chinese hamster cells (line B11ii-FAF28, clone 431) were studied after irradiation by 4He and 12C-ions of various LET (20-360 keV/micrometers), produced by the U-200 heavy ion accelerator. The RBE increases with LET up to the maximum at 100-200 keV/micrometers and then decreases. Cytogenetic analysis was performed on the HPRT-mutant subclones selected from unirradiated Chinese hamster V-79 cells and from HPRT-mutant subclones that arose after exposure to gamma-rays, 1 GeV protons and 14N-ions (LET-77 keV/micrometers), produced by the synchrophasotron and the U-400M heavy ion accelerator.

[Cytogenetic effects of low doses of radiation in mammalian cells: analysis of the hypersensitivity phenomenon and induced resistance].

The induction of cytogenetic damage after irradiation of chinese hamster cells and human melanoma cells within a dose range 1-200 cGy was studied. The anaphase and metaphase analysis of chromosome damage and micronuclei test were applied. The hypersensitivity (HRS) at doses below 20 cGy and the increased radio-resistence at higher doses (IR) were shown with all cytogenetic critheria for both cell lines.

[The dose dependence of cytogenetic damages and the adaptive response of mammalian cells under the action of ionizing radiation at low doses].

The dose-effect dependence of cytogenetic damage after single dose irradiation in the dose range of 0.1-2 Gy and the adaptive response after double-dose irradiation were studied on Chinese hamster and human melanoma cells in culture. The non-linear dose dependencies were found for the induction of chromosome aberrations with decrease in cell radiosensitivity in the definite dose range.

[Effects of low radiation doses on Chinese hamster cells].

The induction of cytogenetic damages after irradiation with single dose of gamma-rays (0.1-2 Gy) have been studied. It is shown non-linear curve for the induction of chromosome aberrations, detected by anaphase method.

[The lethal and mutagenic actions of radiations with different LETs on mammalian cells].

Inactivation and induction of mutations in the HGPRT locus in Chinese hamster cells after irradiation with accelerated heavy ions in the LET range of 20 to 367 keV/micron were studied. In both cases, inactivation and induction of mutations, the LET dependence of RBE is described by a curve with a local maximum in the range of 80 to 100 keV/micron. The maximum RBE value for the mutagenic action is almost twice as high as that for inactivation.

[The mutagenic action of gamma radiation on Chinese hamster cells. The cytogenetic characteristics of the mutants at the HPRT locus].

The peculiarities of mutation induction and cytogenetic characteristics of spontaneous and radiation-induced HPRT mutant clones have been studied. The linear-quadratic dependence of the mutation induction on radiation dose has been found. High heterogeneity of cytogenetic parameters (aneuploidy and chromosome aberration frequency) has been shown in the mutants.

[The effect of intracellular pH on radiation damage to mammalian cells].

In experiments with Chinese hamster cells and Ehrlich ascites tumor cells it has been shown that a decrease in intracellular pH from 7.0 to 6.0, produced by 0.

[Effects of a medium pH on the ability of Chinese hamster cells to repair radiation injuries].

In experiments with Chinese hamster cells at exponential and stationary growth phases, it has been shown that the postirradiation incubation of irradiated cells in a medium with low pH (up to 6.0) promotes the recovery of cells from potentially lethal damages; it has also been found that the recovery from sublethal radiation damages does not depend on the medium pH. The long-term incubation of nonirradiated cells with low pHc causes death of part of cells.

[Effects of induced hyperglycemia on metastasis of Lewis pulmonary carcinoma].

The effect of induced hyperglycemia on the intensity of metastatic spreading of Lewis lung carcinoma was investigated in experiments on mice. Neither long-, nor short-term hyperglycemia, induced at different phases of dissemination, influenced the intensity of metastatic spreading, primary tumor growth, the time of appearance of metastases, and the average life duration of tumor-bearing animals.

[Effects of At-211 alpha irradiation on Ehrlich ascites tumor cells].

The biological effect of 211At alpha-particles has been investigated using the Chinese hamster fibroblasts and Ehrlich carcinoma cells growth in vitro. The mean energy of 211At alpha-particles is 6.8 MeV, LET in tissue is 70-160 keV/microns; the half-life period of decomposition of 211At is 7.

[Patterns in the combined action of irradiation and glucose loading on tumor cells].

It was shown that incubation of Ehrlich ascites tumor cells with glucose or in buffer solutions of low pH decreases their viability. The cell survival rate depends on pH values irrespective of the protoxidation method and oxygenation conditions used. At the same time, radiosensitivity of Ehrlich ascites tumor cells is practically invariable with pH being decreased from 7.

[Lethal effect of glucose load on tumor cells in hypoxia].

The in vitro treatment of the Ehrlich ascites tumour (EAT) cells with glucose for 15 and 60 min under hypoxic conditions leads to a decrease in their survival by a factor of 10(2) and 10(4). Glucose load is ineffective under normal oxygenation. The mass destruction of EAT cells under the influence of glucose takes place within the first 24 hours in the interphase.

Lethal effect of glucose load on malignant cells.

Ehrlich ascites tumor (EAT) cells were treated by glucose load under anoxic conditions (for 15 or 60 min) and/or by gamma-radiation (20 Gy). The efficiency of the treatment was judged from the tumorigenic activity of EAT cell inocula. The markedly increased efficiency of the combined treatment of EAT cells by glucose load in anoxia and by gamma-radiation is due to the additive action of both agents.

Mathematical model of Ehrlich ascites tumor growth from in vitro treated cells.

A mathematical model is proposed describing the dependence of lethality and average life-span in mice on the number of Ehrlich ascites tumor (EAT) cells inoculated both intact or treated in vitro with various agents. Particularly, the effect of ionizing radiation is discussed, and the effect of combined action of two agents is also considered.