Interaction of lactoferrin with plasmid DNA studied by laser correlation spectroscopy]

The interactions of lactoferrin with plasmid DNAs substantially differing in the number of affine regions were studied. The dissociation constants for protein-nucleic acid complexes were determined. The possibility of standardizing the conditions for preparing multicomponent systems for gene-substituting therapy by laser correlation spectroscopy is discussed.     

Conformation of oxytocin studied by laser Raman spectroscopy

The peptide backbone conformation and salient structural details of oxytocin were examined by laser Raman spectroscopy. Spectra were obtained in the solid phase, water, 2H2O, and dimethyl sulfoxide solutions. A distinct Amide I band was obtained at 1663 cm-1 for aqueous and deuterated samples and 1666 cm-1 for the solid sample. A relatively high frequency Amide III band at 1260 cm-1 was obtained. It is concluded that these Amide I and III bands arise from the "beta-turn"-like conformation of oxytocin. The tyrosine side chain, according to the I850 cm-1/I830 cm-1 intensity ratio, is exposed to the solvent. The S-S stretching vibration at 512 cm-1 indicates the conformation of C-C-S-S-C-C in the disulfide bridge of oxytocin in the ring is gauche-gauche-gauche.     

Lysozyme modification by the fenton reaction and gamma radiation

A comparative study was performed on lysozyme modification after exposure to Fenton reagent (Fe(II)/H2 O2) or hydroxyl radicals produced by y radiation. The conditions were adjusted to obtain, with both systems, a 50% loss of activity of the modified ensemble. Gamma radiation modified almost all types of amino acid residues in the enzyme, with little specificity. The modification order was Tyr > Met = Cys > Lys > Ile + Leu > Gly > Pro = Phe > Thr + Ala > Trp = Ser > Arg > Asp + Glu, with 42 mol of modified residues per initial mole of native enzyme. In contrast, when the enzyme was exposed to the Fenton reaction, only some types of amino acids were modified. Furthermore, a smaller number of residues (13.5) were damaged per initial mole of enzyme. The order of the modified residues was Tyr > Cys > Trp > Met His > Ile + Leu > Val > Arg. These results demonstrate that the modifications elicited by these two free radical sources follow different mechanisms. An intramolecular free radical chain reaction is proposed to play a dominant role in the oxidative modification of the protein promoted by gamma radiation.     

The heat denaturation of bacterial ribonuclease studied by infrared spectroscopy]

The thermal denaturation of bacterial ribonuclease in the interval of pH 2.5-7.0 has been investigated by means of infra-red spectroscopy method. The protein melting for pH 2.5 begins at the temperature 25 degrees C and is accompanied by secondary protein structure reconstruction, partially destroying native beta-structure and leading to new denatured conformation appearance of different types of beta-turns. Spectral changes for pH 3.5 and 7.0 are significantly less in the same frequency areas. At the temperature more than 50 degrees C protein aggregation takes place with inter-molecule-beta-form formation.     

The stimulation of postradiation thrombocytopoiesis by low-intensity laser radiation]

In experiments with gamma-irradiated (LD50/30) F1(CBA x C57Bl) hybrid mice, thrombocytopoietic effect of low-intensity laser radiation has been detected. The data obtained may be used in developing modes of haemopoiesis stimulation in a gamma-irradiated organism.     

The metabolism of leukotrienes in blood plasma studied by high-performance liquid chromatography

The metabolism of leukotrienes (B4, C4, D4, and E4) within human plasma was studied and a simple sample preparation is presented. It was demonstrated that leukotriene E4 and leukotriene B4 were stable during incubation at 37 degrees C using the in vitro system. In contrast, leukotriene C4 was metabolized by gamma-glutamyl transpeptidase activities into leukotriene D4 which was further metabolized by dipeptidase activities of plasma into leukotriene E4. The transition state inhibitor of gamma-glutamyl transpeptidase L-serine-borate decreased the metabolism of leukotriene C4 in plasma. Dilution of plasma demonstrated that the dipeptidase was more active compared to the gamma-glutamyl transpeptidase. The metabolizing activities of plasma were functionally characterized by fractionating the plasma proteins.     

The effect of low-intensity laser radiation on blood metabolic indices in the postresuscitation period]

The effect of He-Ne laser radiation (632.8 nm; 0.3 mW/cm parallel to oxygenation on metabolism indices of blood, taken in early postresuscitation period after discontinuation of hemorrhagic shock was studied in vitro. Compared to oxygenation alone, combined therapy resulted in more marked oxygen consumption of the blood, normalization of plasma antioxidant total activity, superoxydismutase erythrocyte catalase activity, the number of double connections in fatty acid chain of general lipids and membrane viscosity were elevated. Regular dependence of lipid peroxidation on a number of metabolic blood parameters is revealed.     

Gastric cancer detection based on blood plasma surface-enhanced Raman spectroscopy excited by polarized laser light

We have recently applied surface-enhanced Raman spectroscopy (SERS) for blood plasma analysis for non-invasive nasopharyngeal cancer detection and obtained good preliminary results. The aim of this study was to develop a more robust SERS spectroscopy based blood plasma analysis method for non-invasive gastric cancer detection. The effect of different laser polarizations (non-polarized, linear-polarized, right-handed circularly polarized, and left-handed circularly polarized) on blood plasma SERS spectroscopy was explored for the first time. Silver nanoparticles as the SERS-substrate were directly mixed with blood plasma to enhance the Raman scattering of various biomolecular constituents. High quality SERS spectra were obtained using a fiber optic probe and a dispersive type near infrared Raman system. Blood plasma samples from gastric cancer patients (n=32) and healthy subjects (n=33) were analyzed. The diagnostic performance for differentiating gastric cancer plasma from normal plasma was evaluated. Principal component analysis combined with linear discriminant analysis (LDA) of the obtained spectral data was used to develop diagnostic algorithms. Classification results obtained from cross-validation of the LDA model based on the four spectral data sets of different laser polarizations demonstrated different diagnostic sensitivities and specificities: 71.9% and 72.7% for non-polarized laser excitation, 75% and 87.9% for linear-polarized laser excitation, 81.3% and 78.8% for right-handed circularly polarized laser excitation, 100% and 97% for left-handed circularly polarized laser excitation. The results from this exploratory study demonstrated that plasma SERS spectroscopy with left-handed circularly polarized laser excitation has great promise of becoming a clinically useful diagnostic tool for non-invasive gastric cancer detection.     

The effect of low-intensity red and infrared laser radiation on the rat arterial and deoxygenated blood

In vitro experiments the effect of low-intensity red or near-infrared laser irradiation on the blood samples (1.5 ml from abdominal aorta of Wistar rats) were studied. The diode laser light (lambda = 650 nm or 808 nm, power density 15.6 mW/cm2, duration 15 min) were used. In some experiments the deoxygenated blood as object for comparison with arterial blood was chosen. Under red laser irradiation we observed a significant increase of average volume of erythrocytes as well as mean amount of free (disaggregated) leukocytes especially in case of the deoxygenated blood. At the same time the concentration of Ca2+ and Na+ were decreased. The effects of infrared laser irradiation on indices mentioned above were not significant. We believe that red low-intensity laser irradiation on the blood is an important factor for theological properties in the field of microcirculation.     

The effect of He-Ne laser radiation on the survival of HeLa cells subjected to ionizing radiation]

A monolayer of HeLa cells, at the stationary phase of growth, exposed to He-Ne laser radiation (632.8 nm; 100 J/m2) either 5 min or 60 min prior to gamma irradiation (0.1-10 Gy; 6.75 Gy/min), or 5 min after irradiation has been investigated. With a 5-min interval between irradiation sessions (both sequences) the survival curves are virtually the same as those for gamma-irradiated cells only. With He-Ne laser radiation delivered 60 min before gamma irradiation with doses exceeding 5 Gy, a fraction of radioresistant cells is identified whose D0 is almost twice as high as D0 of basic cell mass (3.6 and 1.7 Gy respectively. The survival curve becomes a two-component one. A hypothesis is proposed that He-Ne laser radiation activates, in some cells, the processes that promote the repair of radiation damages.     

Effect of hexavalent chromium on eukaryotic plasma membrane studied by EPR spectroscopy

The effect of Cr(VI) anion on an ergosterol-producing strain of eukaryotic yeast Candida albicans and its mutant with ergosterol-less membrane was studied with EPR spectroscopy. 5- and 14-doxyl stearic acid spin probes were used to label the protoplast membrane after removal of the cell wall. In control experiments, the mutant strain exhibited larger rigidity in the membrane than its parental strain. Addition of Cr(VI), at a minimum inhibitory concentration of 0.6 mM, increased the rotational mobility of the spin labels significantly and decreased the temperature of the structural changes in both strains, in the temperature range between 0 and 30 degrees C. The ergosterol-less mutant, having a membrane composition with increased polyunsaturated fatty acid content, exhibited higher Cr(VI) sensitivity. Treatment of the membrane with Cr(VI) for 10 min already resulted in an increase in membrane fluidity. An EPR signal of Cr(V) was detected which reached maximum amplitude after 120 min of treatment with Cr(VI). Further chemical reduction of Cr(V) in the absence of extracellular Cr(VI) led to a lack of detectable paramagnetic chromium intermediates within 200 min.     

The microcirculatory bed of the normal rat uterus and in exposure to laser radiation

By means of scanning electron microscopy of corrosive casts angioarchitectonics of mucous and muscular membranes of the white rat uterus has been studied at diestrus phase, normal and under influence of laser irradiation with exposition of 1 min and 1 h. The morphometric investigation performed has proved presence of local peculiarities in organization of the uterine capillary bed. After irradiation for 1 min a noticeable increase in transversal diameter and capillary density is observed, numerous protrusions appear on their walls. When irradiation lasts for 1 h a relative loose of the uterine capillary network is observed, which is especially manifested in endometrium: capillaries demonstrate an increased convolution and decreased diameter.     

Localization of carotenoids in plasma low-density lipoproteins studied by surface-enhanced resonance Raman spectroscopy

Surface-enhanced resonance Raman scattering (SERRS) spectra were measured for the beta-carotene and lycopene carotenoids present in low-density lipoproteins (LDLs), which were isolated from human plasma and adsorbed on roughened silver surfaces. The silver surface was modified by formation of a self-assembled monolayer (SAM) of carboxylate-terminated linear alkanethiols in order to simulate the LDL binding region of the cellular LDL receptor. Thiols of different chain length were used to produce SAMs of varying thicknesses. It was shown that carotenoids are not released from the LDL particle upon adsorption onto the bare and thiol modified silver surfaces. The SERRS studies indicated that beta-carotene and lycopene were present in the shell of the LDL particle. The dependence of SERRS on the distance from the silver surface was different for beta-carotene and lycopene in LDL. This observation suggests that the two carotenoids are located in different places of the LDL particle.     

Haematocytometrical changes in chicken blood to acute 60Co gamma radiation

Newly hatched white leghorn chicks (Gallus domesticus) subjected to single whole body 2.25 Gy (225 rads) gamma radiation exposure at the dose rate of 0.50 Gy/sec (50 rads/sec), were studied for changes in a number of haematological parameters at days 1,3,5,7,14 and 28 post irradiation during development. The sudden decline and gradual recovery in total RBC and WBC counts and the level of Hb and Hct along with MCV, MCH and MCHC values evaluation indicates a high regenerative capability of leghorn chicks.     

Heparin and the heparin-precipitated human blood plasma fraction in the rosette formation reaction]

Experiments were conducted on CBA mice. The effect of heparin and of the fraction of human blood plasma precipitated by heparin (FPH) on the course of the specific immunity reaction, i.e. of rosette-formation, was studied. Inhibition of the mentioned reaction by FPH was revealed. No such effect was produced by heparin. Experiments were carried out in vitro. The results of the mentioned experiments were compared with literature data on the effect of heparin and FPH on other immunological reactions. A supposition was put forward that these substances interacting with lymphocytes had different points of application: heparin-cellular membrane, FPH-superficial cell receptors.     

Pheophytin-protein interactions in photosystem II studied by resonance Raman spectroscopy of modified reaction centers

Soret-excited resonance Raman spectra of two types of pheophytin-exchanged photosystem II RCs are reported. The cofactor composition of the reaction centers was modified by exchanging pheophytin a for 13(1)-deoxo-13(1)-hydroxypheophytin a, yielding one preparation with selective replacement of the photochemically inactive pheophytin (H(B)) and a second one exhibiting total replacement of H(B) and 40% replacement of H(A), the primary electron acceptor. Resonance Raman spectra indicate that the other bound cofactors present are not significantly perturbed by Pheo substitution. The resonance Raman contributions from H(A) and H(B) in the carbonyl stretching region are identified at 1679 and 1675 cm(-)(1), respectively, indicating that both pheophytin molecules in the photosystem II reaction center have hydrogen-bonded keto-carbonyl groups. This conclusion differs from what is observed in the functionally related RCs of purple non-sulfur bacteria, where the keto-carbonyl group of H(B) is not hydrogen bonded, but confirms predictions from models based on protein sequence alignments.     

The nature of the toxic properties of the blood plasma of gamma irradiated rats

In addition to the growth of low molecular weight quinoid radiotoxins the toxic effects of albumin were registered in rat plasma 4-24 h following gamma-irradiation. It is assumed that adducts of albumin with quinoid radiotoxins are formed and contribute to the development of radiation injury to critical organism tissues.