Changes in somatosensory evoked potentials in patients with vertebrogenic pain syndromes treated by electroacupuncture

Application of electroacupuncture (EAP) of the segmental points to patients with vertebrogenic algesic syndromes decreased amplitude of N150 and P240 waves recorded from vertex to painful electrocutaneous stimulation in the region innervated by an affected root. As distinct from EAP of segmental point auricular EAP not only decreased the amplitude of late components of evoked potentials (EP), but also increased it, direction of EP changes depending on the character of sensitivity disorders. It is suggested that effect of EAP-evoked EP changes in patients with hypalgesia is determined by two oppositively acting factors: by a decrease of nociceptive afferent impulsation intensity as a result of the antinociceptive system activation and by an increase of the afferent impulsation intensity due to recovery of function of central terminals in primary sensory neurons.     

An evaluation of the conformational changes in the superhelical DNA of eukaryotic cells by direct nucleoid fluorometry. II. The characteristics of the change in acridine orange fluorescence in studying the superhelical DNA of rat thymocytes

Comparative studies of acridine orange (AO) and ethidium bromide interactions with supercoiled DNA (scDNA) of thymocytes were performed in which various conformational changes were induced. AO may be efficiently used for evaluation of conformational alterations of scDNA. Moreover, employing the maximum values of AO fluorescence allows to determine the maximum levels of scDNA relaxation.     

Effect of novobiocin on degradation and repair of the superhelical structure of nuclear DNA from rat thymocyte fractions

A study was made of the action of novobiocin on degradation and repair events in supercoiled nuclear DNA from three thymocyte fractions obtained by ficoll-paque gradient sedimentation. When added before gamma-irradiation novobiocin (1.9 mg/ml) exerted a radioprotective effect during the "second wave" of supercoiled DNA degradation. It is suggested that this effect may be due to the inhibition of DNA topoisomerase II.     

Vanadate inhibition of ATP and p-nitrophenyl phosphate hydrolysis in the fragmented sarcoplasmic reticulum.

The vanadate inhibition of the Ca(2+)-ATPase activity was analysed both in intact sarcoplasmic reticulum vesicles and in the presence of low concentrations of Tween 20, using ATP and p-nitrophenyl phosphate as substrates. The saturation of the internal low-affinity calcium-binding sites protects the enzyme against vanadate inhibition, because: (1) p-nitrophenyl phosphate hydrolysis is not inhibited by vanadate in intact vesicles, but inhibition developed after solubilization with detergents; (2) the vanadate inhibition of the p-nitrophenyl phosphate hydrolysis in solubilized preparations is prevented by free Ca2+ concentrations higher than 10(-3) M and vanadate competes with calcium (10(-5)-10(-3) M); and (3) the vanadate inhibition of ATP hydrolysis is decreased with an increase in vesicular Ca2+ concentration. The presence of magnesium ions is indispensable for the vanadate effect. The vanadate inhibition is non-competitive with respect to Mg-p-nitrophenyl phosphate and uncompetitive with respect to Mg-ATP. However, in the presence of dimethyl sulfoxide, which facilitates phosphorylation of the enzyme, the inhibition is converted to a competitive one with respect to a substrate. The results suggest, that in the process of enzyme operation vanadate interacts with the unliganded E form of Ca(2+)-ATPase, occupying probably an intermediate position between the E2 and E1 forms, with the formation of an E2 Van complex, that imposes the inhibition on the Ca(2+)-ATPase activity.     

Modulation of the nociceptive flexor reflex by the electrostimulation of auricular acupuncture points

Nociceptive flexor reflex (NFR) in patients with vertebrogenic lumbosacral pain syndromes was recorded before and after the ipsi- and contralateral auricular electroacupuncture (AEAP). Changes in NFR were observed after ipsi- and contralateral AEAP, each producing facilitatory and inhibitory effects on NFR. Facilitatory influence of AEAP on NFR correlated with hypalgesia, that apparently reflected recovery of the afferent input peculiarities.     

Univalent ions in phospholipid model membranes: Thermodynamic and hydration aspects

By means of differential scanning calorimetry, effects of systematic series of Group I and VII ions on the phase state of model multibilayer dimyristoylphosphatidylcholine (di(14:0)PC) membranes have been studied at a lipid/ion molar ratio of 3/1. The sign-changing correlations between the ionic radii of cations and temperature shifts of di(14:0)PC phase transition were obtained. For cosmotropic Li⁺ and Na⁺, the observed shifts were positive (LiCl: ΔT _m = 0.6°C; ΔT _p = 1.9°C), whereas chaotropic K⁺ and Rb⁺ presence resulted in negative shifts (RbCl: ΔT _m = ?0.3°C; ΔT _p = ?2.5°C). The anions (Cl^?, Br^?, I^?) showed a similar effect increasing with the ion chaotropicity. An essentially weaker effect of Cs⁺ as compared to other alkali metal ions (CsCl: ΔT _m ≈ 0°C; ΔT _p = ?0.1°C) can be one of the reasons of its accumulation in living organisms. Generalization of all available data allowed us to specify some important factors of lipid-ion interactions that should be taken into account in further investigations in this field.     

The characteristics of interactions of pharmaceuticals and their active ingredients with lipid membranes

A comparative study of the effects of the active pharmaceutical ingredients of amixin, aspirin, metronidazole, phenibut, and fenspiride, as well as corresponding pharmaceuticals on lipid membranes was carried out. Lipid membranes of L-α-dipalmitoylphosphatidylcholine and native carp spermatozoa were used as models. A decrease in the melting temperature of L-α-dipalmitoylphosphatidylcholine membranes in the presence of all active ingredients and pharmaceuticals was found using differential scanning calorimetry. The only exception was the group of phenibut, where a splitting of the melting peak was observed. It was found that in the pharmaceuticals studied the active pharmaceutical ingredients exhibit a determinative membranotropic effect, whereas excipients play a modulating role. Changes in the parameters of water ν_ОН bands in the L-α-dipalmitoylphosphatidylcholine membranes containing active pharmaceutical ingredients were quantitatively characterized by Fourier transform infrared spectroscopy. According to these parameters, the effect of the phenibut group differed in these parameters from that of the other ingredients. The changes of ν_ОН bands caused by excipients were elucidated. An increase in the permeability of carp sperm cell membranes to water was observed in vitro for pharmaceuticals that induced a decrease in the phase transition temperature of a model membrane (amixin) and lipid lateral phase separation (phenibut).     

Photoconductivity of Silver Nanoparticle Ensembles on Quartz Glass (SiO2) Supports Assisted by Localized Surface Plasmon Excitations

We have studied the conductivity and photoconductivity in silver nanoparticle ensembles on quartz glass substrates. We observed a significant increase of the photoconductivity if the localized surface plasmon resonance in the metal nanoparticles was excited. A detailed analysis of the temperature dependence of the conductivity as well as dependences of the conductivity and photoconductivity on the amount of deposited metal led to the mechanism of the charge transfer in these structures. We found that the primary role in this mechanism is due to defects in the quartz glass structure which act as traps for electrons.     

Oxidation of organic and biogenic amines by recombinant human hephaestin expressed in Pichia pastoris

Hephaestin is a multicopper ferroxidase involved in iron absorption in the small intestine. Expressed mainly on the basolateral surface of duodenal enterocytes, hephaestin facilitates the export of iron from the intestinal epithelium into blood by oxidizing Fe(2+) into Fe(3+), the only form of iron bound by the plasma protein transferrin. Structurally, the human hephaestin ectodomain is predicted to resemble ceruloplasmin, the major multicopper oxidase in blood. In addition to its ferroxidase activity, ceruloplasmin was reported to oxidize a wide range of organic compounds including a group of physiologically relevant substrates (biogenic amines). To study oxidation of organic substrates, the human hephaestin ectodomain was expressed in Pichia pastoris. The purified recombinant hephaestin has an average copper content of 4.2 copper atoms per molecule. The K(m) for Fe(2+) of hephaestin was determined to be 3.2μM which is consistent with the K(m) values for other multicopper ferroxidases. In addition, the K(m) values of hephaestin for such organic substrates as p-phenylenediamine and o-dianisidine are close to values determined for ceruloplasmin. However, in contrast to ceruloplasmin, hephaestin was incapable of direct oxidation of adrenaline and dopamine implying a difference in biological substrate specificities between these two homologous ferroxidases.     

Effect of electric stimulation of auricular acupuncture points on H-reflex

The non-nociceptive H-reflex in the musculus soleus were recorded before and after auricular electroacupuncture (AEAP) in patients with vertebrogenic pain syndrome. Changes of the H-reflex on the side of the pain syndrome were observed after ipsi- and contralateral AEAP, the latter producing effect more often. Changes of H-reflex are mainly of facilitating character (71.4%) and, rarely, of inhibitory character (14.3%). In the part of patients AEAP produced distinct facilitation of M-response.