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Biomedical subjects

E M Mil'

Publications and source records attributed to E M Mil'.

At least 19 recordsLinked to original sources
PubMed2006

[Comparison of blood-serum p53 concentrations in patients with advanced breast tumors before and after chemotherapy].

Investigations of the role of p53 in tumorigenesis and growth, implementation of antitumor effect of cytostatics as well as emergence of tumor resistance have generally received great emphasis. Since most research was mostly concerned with use of tumor tissues, its dynamic aspects were ignored. Our study was concerned with p53 assay of blood serum from 10 patients with advanced breast tumors who underwent tests before and after a second cycle of chemotherapy. Due to immunoblotting technique, p53 was identified in all patients. Its concentration varied significantly and was twice as high in some as compared with the others. Prior to treatment, distinct differences were recorded in content as well as and in the nature of its age-dependent variation after chemotherapy. The highest levels were recorded in the age group over 60 yrs. In most patients (5 out of 6) under 55, post-treatment concentrations rose, on the average, by 13% while in all 4 cases of more than 60, they dropped by an average of 18%.

Adult↗
PubMed1988

[Local homology of amino acid sequences of histones H3, H4 and the protein repressor lambda Cro. Possible conformation of homologous histone sites in DNP].

A mathematical analysis of amino acid sequences was carried out with a view of detecting possible homology between histones H3 and H4 and repressor-activator proteins of prokaryotes according to the A. I. criterion which reflects the similarity of their primary structure. It was found that the sites of eukaryotic histones H3 (102-123) and H4 (68-85) and site alpha 3 (24-25) of the prokaryotic repressor protein lambda Cro, i. e., the site of protein interaction with DNA, reveal a statistically significant homology. The A. I. value for the H3 site of lambda Cro is 3.37, that for the H4 site of calf thymus and sea horse is 3.28. The amino acid sequences of these proteins in the alpha 2-alpha 3 site, i. e., the site in which the homology between amino acid sequences of histones and DNA-binding proteins had been established previously, with regard to similarity of their secondary structure of the helix-turn-helix type, were analyzed. A pairwise comparison of H3 and protein lambda Cro showed that the A. I. value for histones H3 from various sources is approximately 2.7; however, the homology of the alpha 2 site is lower than that of site alpha 3. It is concluded that there exists an evolutionary relationship between homologous segments of histones H3 and H4 and protein lambda Cro, which can be preserved in order to maintain a definite secondary structure, presumably for binding to DNA.

Amino Acid Sequence↗
PubMed1986

[Characteristics of sulfhydryl groups of histone H3 from the calf thymus using mercury-containing nitroxyl radicals].

The interaction between total histone and deoxyribonucleoprotein (DNP) preparations from calf thymus with mercury-containing nitroxyl radicals in low ionic strength solutions, 2 M NaCl and urea was investigated. It was found that the label is rapidly incorporated into the SH-groups of histone H3 to produce characteristic EPR signals. Titration of SH-groups within DNP demonstrated that in low ionic strength solutions only one SH-group (presumably, the SH-group of the cysteine residue in position 110) is accessible to the reagents. After dissociation by 2 M NaCl, two SH-groups become titrable; however, the EPR spectra point to differences in the conformational state of these two groups. In 4 M urea, these differences are compensated for by structural disintegration. The spin labels may be used for the analysis of SH-groups under different conditions and at different functional states of nucleoproteins.

Animals↗
PubMedDate not supplied

[Changes in the EPR spectra of the nitrosyl complexes of blood proteins in the low-intensity whole-body irradiation of mice].

After NO adding to mice blood and isolated erythrocytes ESR signal of nitrozyl complex HbNO (g = 2.07, g = 1.98) and NO-induced MetNg (g = 6.0) were registered. It was shown that the intensity of ESR spectra of these complexes increased after radiation of mice with a dose of 0.06, 0.6 and 5.4 cGy. Low-dose irradiation (0.6 and 0.06 cGy) caused the change in the form of ESR spectra of HbNO (g = 2.07), which is indicative of the shift from T-structure to R-structure and of the preferred formation of R-conformations of oxyhemoglobin in blood. It was found that dependence of NO-induced MetHb signal on irradiation dose is bimodal that may be connected with nonlinear response of the cells to irradiation and retarded adaptive response after radiation with low doses.

Animals↗
PubMedDate not supplied

[Changes in levels of p53 protein, immunoglobulin L-chains, and iron complexes in mice of leukosis strain AKR following low dose irradiation].

Changes in the content of protein p53 (regulator of the cell cycle) L-chains of immunoglobulins, and iron complexes (Fe2+) during the development of spontaneous leukosis in AKR mice and upon irradiation of animals with a dose of 1.2 cGy were studied by ESR spectroscopy, electrophoresis, and immunoblotting. It was found that irradiation leads to an increase in the incidence of leukoses in males by 7% and a decrease in life duration of females. A decrease in the content of protein p53 and L-chains in immunoglobulins in males and females was observed; however, in females, the decreases was less pronounced because the content of these proteins in females is naturally decreased. In mice irradiated with low doses at the age of three- to four months, a decrease in the amount of iron complexes at a later age (seven- to eight months) was registered. These data suggest that there is a relationship between the induction of protein p53 and the content of immunoglobulin L-chains in the blood serum of animals.

Aging↗
PubMedDate not supplied

[Titration of SH-groups of histone H3 in a DNP preparation of normal and neoplastic animal cells with a mercury-containing spin marker and with a DTNB preparation].

DNP samples isolated from the cells of calf thymus and Ehrlich ascite carcinoma of mice were examined. SH-groups of histone H3 of chromatin from these cells were titrated with mercury-containing spin label and with DTNB under joint action of different salt and sarcosyl concentrations on DNP. The results revealed differences in accessibility and titration of histone H3 SH-groups in DNP of normal and tumor cells with DTNB, as well as in molecular dynamics of the mercury-containing spin label introduced to these SH-groups.

Animals↗
PubMedDate not supplied

[P53 under low-intensity inluence of physical and chemical nature (ionizing radiation and antioxidant)].

It was found that low-intensity ionizing radiation and the antioxidant fenozan at a low concentration (10(-14) M) produce opposite effects on the content of protein p53 in the blood serum of mice. Thus, low-intensity gamma-irradiation of AKR mice with a dose of 1.2 cGy (0.6 cGy per day) led to a decrease in the content of p53 and acceleration of leukosis, whereas fenozan, which has membranolytic and radioprotective properties, when injected intramuscularly to F1 mice (CBA + c57 black) increased the content of p53. However, the dynamics of the activation of protein p53 depended on the concentration of fenozan (10(-4) or 10(-14)), which may be due to the difference in its binding to the membrane and the changes in its antioxidative properties depending on concentration.

Animals↗
PubMedDate not supplied

[Structural transitions in DNA, isolated from normal and neoplastic cells].

A decrease of temperature transition in spin-labeled DNA isolated from leucose cells compared with normal cells is found. It is shown by kinetic formaldehyde method that it may be the result of many defects in the secondary structure of macromolecule in DNA1. The spin label method is shown to be used for the analysis of DNA macromolecule damaged with small irradiation doses. Various radiosensitivity of DNA isolated from the blood of normal and leucose cells is observed.

Animals↗
PubMedDate not supplied

[The action of benzimidazole derivative preparations on the formation of DNA-protein cross-links in the UV irradiation of chromatin].

Effect of benzimidazole-derivatives on the DNA-protein binding formation was studied after UV-radiation of chromatin. These derivatives were shown to protect chromatin from UV-induced DNA-protein binding formation. Structural analog contained two aminomethyl residuals sensibilized additional binding formation in chromatin. Results suggested, that benzimidazole interacted with DNA, while aminomethyl groups interacted with protein and sensibilized binding of DNA with histone H1.

Animals↗
PubMedDate not supplied

Complex formation of spin-labeled 9-aminoacridine with DNA and polynucleotides.

Complex formation between spin-labeled 9-aminoacridine and DNA or polynucleotides has been studied by differential spectrophotometry and ESR. The differential spectra of the strong type 9-aminoacridine-DNA complex showed characteristic absorption bands at 270 and 290 nm, and the intensity ratio of these bands varied according to the degree of DNA denaturation. The ESR spectra of this complex were characterized by slow rotation of the radical; as the macromolecule became increasingly denatured and in the polynucleotide complex, a rapid signal appeared in the ESR spectrum. The temperature at which DNA undergoes a structural transition in the premelting region could be determined from the temperature dependence of the ESR spectral form of the dye-DNA complex. The spectral characteristics of the complexes give additional information about structural disturbances in DNA.

Animals↗