[A microcalorimetric study of collagen hydrated water in a temperature range 20-100 degrees C].

A new method for determining bound water was developed, which is based on precise measurements of the enthalpy of water evaporation from a sample using differential scanning calorimetry.

[Effect of toluene on stability of chromatin of white rat hippocampus and olfactory bulb in vivo. Microcalorimetric study].

The denaturation heat parameters of hippocampus and olfactory bulb nodulus tissues were determined. The total denaturation heat calculated from the areas of endotherms I-IX onto which the dependence deltaH = f(T) is factorized equals to 13.03 +/- 1.

[The influence of the peptide bioregulator prostamax on heterochromatin of human lymphocytes in situ].

It was shown that chromatin contained in human lymphocytes has two stages of denaturation: with T(d)VII = 94.4 degrees C, Q(d)VII = 50.8 J/g DNA, and T(d)VIII = 105.

[Microcalorimetric study of native cells of the microalgae Spirulina platensis in the temperature range (2-55)C].

Thermal effects occurring upon heating a culture of blue-green microalgae Spirulina platensis in the temperature range 5-55 degrees C were studied. Under these conditions, an intensive heat evolution was observed. The heat evolution-versus-temperature curve has a peak with a maximum at approximately 45 degrees C and two distinct shoulders at approximately 25 and 40 degrees C.

[Independent denaturation of albumin and globulins in human serum].

The independent melting of albumin, gamma-globulin, transferrin, and protease inhibitors in the composition of donor blood serum was studied by differential scanning microcalorimetry. It was found that the number of domains in gamma-globulin in donor blood serum and in diluted solutions is the same, whereas the number of domains of albumin in solution and in the composition of blood serum is three and two, respectively. In blood serum, the N-terminal domain melts by the "all-or-none" mechanism.

[Microcalorimetric study of human serum].

It was established that albumin of donor blood serum denatures in two temperature ranges. It is shown that the first stage of denaturation with Td = 61.5 degrees C is dominant and corresponds to melting of regions not bound to fatty acids.

[Different character of zinc ion binding with lactate dehydrogenase M4 in diluted and concentrated solutions].

The study of the melting characteristics of lactate dehydrogenase M4 and Zn/lactate dehydrogenase at pH 6.5-8.5 by microcalorimetric methods shows that in dilute solutions of the enzyme (0.

[Microcalorimetric study of the effect of mitoxantrone on chromatin DNA in vivo].

The influence of antitumor drugs--mitocsantron on the chromatine of tumor cells spleen tissue of BALB/c-mice has been established. Two-stage denaturation process of chromatine in normal cells has been shown. The first stage--thermolabel domain can be described by the following transition parameters: Td1 = 72, delta Td1 = 6.

[Microcalorimetric study of the effect of mitoxantrone on chromatin DNA in vivo].

The influence of antitumor preparation--mitoxantrone on chromatin in tumor cell composition of BALB/c mouse spleen tissue was studied by the method of scanning microcalorimetry. It was shown that chromatin in normal cell composition denatured in two stages. The first stage--thermolabile domain is characterized by the transition parameters: T1d = 72, delta T1d = 6.

[The effect of benz(a)pyrene on the thermal characteristics of DNA in vivo and in vitro].

Thermal properties of DNA-benz(a)pyrene complex and chromatin within liver cells in BALB/c mice and Macaca fascicularis monkeys after benz(a)pyrene administration were studied using a highly sensitive differential scanning microcalorimeter designed for investigations of dilute biopolymer solutions and complex biological systems. It was shown that benz(a)pyrene (BP) had different efforts on DNA in vivo and in vitro. It was established that at a molar ratio r < 0.

[Thermal properties of chromatin in vivo during interaction with cis[Pt(CuO)2(CuOH)2]].

Thermal properties of chromatin in cell composition of BALB/c mice and whole chromatin at injection of cis-Pt(CuO)2(CuOH)2 to experimental animals were studied by high sensitive DSM assigning for investigating complex biological systems. It is established that injection of cis-Pt(CuO)2(CuOH)2 to leukemic mice in vivo changes the thermal characteristics of spleen cells, so that they look like the thermal properties of the healthy mice spleen cells. It was supposed that small doses of Pt(CuO)2(CuOH)2 in the case of leukemia show anticarcinogenic properties and the overdoses promote malignization; in the norm at any concentration of the injected salt cancerogenic properties are exhibited.

[Scanning microcalorimetry of the blood].

The age dependence of haemoglobin denaturation temperature in the composition of erythrocytes is established. Children have a much more expressed correlation of this temperature depending on the type and stage of disease than the adult. It is found that children ill with leukemia have haemoglobin, the value of heat denaturation of which is decreased about 15-25% in relation to the norm.

[Calorimetry of chromatin and DNA from ascitic cells of C3HA mice in the presence of copper ions].

The process of chromatin denaturation in the composition of C3HA line mice ascites cells was investigated by the method of scanning microcalorimetry. It is shown that copper ions injected into ascites tumour are inculcated in DNA double helix and injure it, and this caused disorder of high ordered chromatin structure.

[Microcalorimetric study of the oncogene EJ and proto-oncogene EC in the plasmid pBR 322].

Thermodynamic parameters were obtained of melting of the linear form of plasmids pBR 322 and plasmids pBR 322 with incorporated oncogene EC. The melting temperature of the main stage of heat absorption of the oncogene EJ was shown to be 1.6 degrees C lower than in the norm (EC).

[Calorimetric study of the denaturation of chromatin and its components].

Two-stage process of chromatin denaturation was studied. To understand the nature of heat absorption of these stages their degree of their reversibility was investigated. Some stages of heat absorption observed on the curves of chromatin and mononucleosome heat absorption reflect melting of different levels of chromatin DNA organization.

[Thermography of catalase crystals: the role of crystallographic modification].

Study of the heat destruction process of catalase crystals by the method of scanning microcalorimetry has revealed the influence of crystallographic modification on protein macromolecules denaturation at relatively low heating rates.

[Cooperative thermal transitions in normal and tumor cells].

It is established that chromatin denaturation in the cell composition under conditions approximating to equilibrium is a quasistatistical process. It is shown that thermal treatment of tissues in chromatin composition enables to reveal the thermostable block with the following parameters of denaturation Td = 89 degrees C, Td = 3.5 degrees C and Qd = (28 +/- 4) J/g DNA.

[Microcalorimetric study of intact nucleoproteins].

It has been shown that melting of native chromatin complex in tissues and cells is a one stage process with transition parameters Tm = 82 +/- 1 degrees C, delta Tm = 6 degrees C and Qm = (24 +/- 3) cal/g DNA. A conclusion is made that the difference in melting temperatures of chromatin complex and DNA, which is 12 cal/g DNA, corresponds to the melting of secondary and tertiary structures of chromatin. It is shown the destruction of significant part of the secondary and tertiary structures of chromatin by the chromatin complex isolation from tissues and cells.

[Heat denaturation of crystalline and dissolved leghemoglobin].

Heat transitions in crystals of leghemoglobin (LH) are studied by means of scanning microcalorimetry and microscopy. It has been found that LH crystals do not melt and their loss of crystal lattice is due to the denaturation of protein globules inside the crystal. Peculiarities of the crystal state (as compared to the solution) are shown in an increase in the cooperative character of heat transition and relaxation time of the system.

[Cooperative nature of the denaturation process in tissues and cell nuclei].

The heat absorbance curves for liver tissue, liver tissue of embrione and for splin of white rats reveal two peaks corresponding to melting processes of protein and DNA. There are three peaks for cell nucleous: the first (corresponding lower temperature) responsible for membrane melting process. Two other peaks coinside with nucleoprotein denaturation process.

[Thermal properties of DNA and polydeoxyribonucleotides in a wide range of ionic concentration of neutral salts and a polymer].

deltaHm, deltaT, Tm of melting of polydesoxyribonucletides polydAdT,, polyd(A--T)d(A--T), polyd(A--C)d(T--G) and DNA with different basic composition in a wide range of (10-2--4.0 M) ions (C2H5)4N+, Cs+ and Na+ were determined by the method microcalorimetry. It was established that the difference in melting heats of deltaHpolydAdT--deltaHpolyd(A--T)d(A--T) being approximately 0.

[Physical state of crystalline proteins. III. Structure of thermal heating curves].

By microcalorimetry the processes proceeding in crystals of aspartate-transaminase and catalase during their termal heating have been studied. Decrease of temperature range within which heat is absorbed during a reduction of heating rate shows that the process of the destruction of crystal order is determined by the denaturation of protein molecules. A thin structure of heat absorption curve is found at some heating rates.