[Antimicrobial activity of stable silver nanoparticles of a certain size].

Conditions for obtaining stable silver nanoparticles smaller than 10 nm were developed using a binary stabilizer polyvinylpyrrolidone/sodium dodecylsulphate in optimal ratio. Optical spectra, morphology and dependence of size of the nanoparticles on the amount of reducing agent were studied. Colloidal solutions of nanosilver showed a high bactericidal activity against strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, and fungicidal activity against Candida albicans. The mechanism of action of nanosized silver on microbial cell was examined by laser scanning confocal microscope using fluorescent label. First step of antimicrobial effect on microorganisms was membrane damage and penetration of silver nanoparticles into the cell. Prolonged stability of nanoparticles and their antimicrobial activity over the past two years were showed.

Bovine viral diarrhea virus cyclically impairs long bone trabecular modeling in experimental persistently infected fetuses.

Persistent infection (PI) with bovine viral diarrhea virus (BVDV) has been associated with osteopetrosis and other long bone lesions, most commonly characterized as transverse zones of unmodeled metaphyseal trabeculae in fetuses and calves. This study was undertaken to characterize the morphogenesis of fetal long bone lesions. Forty-six BVDV-naïve pregnant Hereford heifers of approximately 18 months of age were inoculated with noncytopathic BVDV type 2 containing media or media alone on day 75 of gestation to produce PI and control fetuses, respectively, which were collected via cesarean section on days 82, 89, 97, 192, and 245 of gestation. Radiographic and histomorphometric abnormalities were first detected on day 192, at which age PI fetal long bone metaphyses contained focal densities (4 of 7 fetuses) and multiple alternating transverse radiodense bands (3 of 7 fetuses). Day 245 fetuses were similarly affected. Histomorphometric analysis of proximal tibial metaphyses from day 192 fetuses revealed transverse zones with increased calcified cartilage core (Cg.V/BV, %) and trabecular bone (BV/TV, %) volumes in regions corresponding to radiodense bands (P < .05). Numbers of tartrate resistant acid phosphatase positive osteoclasts (N.Oc/BS, #/mm(2)) and bone perimeter occupied (Oc.S/BS, %) were both decreased (P < .05). Mineralizing surface (MS/BS, %), a measure of tissue level bone formation activity, was reduced in PI fetuses (P < .05). It is concluded that PI with BVDV induces cyclic abnormal trabecular modeling, which is secondary to reduced numbers of osteoclasts. The factors responsible for these temporal changes are unknown but may be related to the time required for osteoclast differentiation from precursor cells.

Antibacterial and Antimycotic Activity of Cotton Fabrics, Impregnated with Silver and Binary Silver/Copper Nanoparticles.

Effective method of obtaining of the bactericidal bandage materials by impregnation of cotton fabric by aqueous solutions of silver and copper salts followed by a certain regime of heat treatment is developed. The study of obtained materials by methods of optical spectroscopy, electron microscopy, and X-ray phase analysis showed the formation of crystalline silver nanoparticles (NPs) and bimetallic Ag/Cu composites with the corresponding surface plasmon resonance (SPR) bands in the absorption spectra. High antimicrobial and antimycotic properties of tissues with low concentrations of Ag and Ag/Cu nanoparticles (Ag/Cu NPs) (in the range 0.06-0.25 weight percent (wt%) for Ag and 0.015-0.13 wt% for Ag/Cu) is confirmed in experiments with a wide range of multidrug-resistant bacteria and fungi: Escherichia coli, Enterobacter aerogenes, Proteus mirabilis, Klebsiella pneumoniae, Candida albicans yeasts, and micromycetes. Textile materials with Ag NPs demonstrate high antibacterial activity, while fabrics doped with bimetallic composite Ag/Cu have pronounced antimycotic properties. Bactericidal and antifungal properties of the obtained materials do not change after a washing. Production of such materials is extremely fast, convenient, and cost-effective.

[The use of wild animals in radioecological monitoring]. / Opyt ispol'zovaniia dikikh zhivotnykh v radioékologicheskom monitoringe.

Radionuclide content in muscular and osseous tissues of elks and wild boars was determined by means of spectrum analysis. The radioactive caesium accumulation dynamics in muscular tissues of elks and wild boars from 1986 till 1992 years is presented.

Possible adaptation to strong magnetic fields.

Animal adaptation to a strong magnetic field was investigated. Mice were exposed to 30-day total-body continuous effects of a constant magnetic field (CMF) of 1.6T, and their physiological responses were assessed. Analysis of the data obtained showed that different parameters varied in a dissimilar manner. Red blood changes returned to normal in the course of the experiment. Leucocytosis and increased content of catecholamines and corticosterone of blood and adrenals persisted throughout the exposure. Changes in the spermatogenic epithelium were most distinct after the exposure. The recovery of certain parameters during the CMF exposure is indicative of adaptation of some physiological systems. The adaptation is, however, incomplete as suggested by the long persisting stress manifestation. Reticulocytopenia and spermatogenetic abnormalities found after exposure are of particular importance.

[Cerebral evoked potential recovery cycles following exposure to a constant magnetic field in rats]. / Tsikly vosstanovleniia vyzvannykh potentsialov mozga pri vozdeistvii postoiannogo magnitnogo polia u krys.

The recovery cycles of somatosensory evoked potentials (EP) in the cerebral cortex, hypothalamus and cerebellar cortex were studied in experiments on rats. During the action of constant magnetic field (CMF) with an intensity, subthreshold for the changes in biopotentials, as well as after intensive magnetic influence, the recovery of the response to test stimulation of the nerve was more rapid and more complete, the duration of areactivity and subnormality periods was reduced and phenomenon of facilitation was observed. The obtained data testify to a rise in the level of excitability of the studied brain structures under the effect of CMF. Paired stimulation of sciatic nerve with definite interstimuli intervals may also lead to the intensification or provocation of the "magnetic effect"--the appearance in the EP structure of additional phases under the effect of the subthreshold field.

["Open field" rat behavior following exposure to a magnetic field]. / Povedenie krys v "otkrytom pole" posle vosdeistviia magnitnogo polia.

The influence of the magnetic field on a complex physiological reaction in the "open field" test was studied in experiments on 160 rats. The behaviour in the "open field" was observed within three consecutive days simultaneously of control rats and those subjected directly before each test to a three to four hour general effect of a weakly pulsing magnetic field with a 0.3 T induction or a strictly constant magnetic field of 1.6 T. Individual behavioural reactions to the MF action were characterized by great variability and could be of different direction. According to mean data, the 0.3 T MF action depressed motor and investigating behaviour of the rats in the "open field". An increase of magnetic induction up to 1.6 T, far from enhancing the inhibitory effect, showed a tendency towards activation of behaviour in the "open field". Apparently, in conditions of the intensities used, pulsation is a biologically more significant characteristics of the magnetic field than the magnitude of induction.

[The character of changes in the background and superimposed rhythmics of cerebral biopotentials in rabbits exposed to a steady magnetic field of high intensity]. / O kharaktere izmeneniia fonovoi i naviazannoi ritmiki biopotentsialov golovnogo mozga u krolikov pri vozdeistvii postoiannogo magnitnogo polia vysokoi napriazhennosti

During a total action of a static magnetic field (SMF) of 1000--4000 Oe, high-amplitude synchronized discharges appear in the electrograms of the cortical and subcortical parts of the rabbit brain. An automatic frequency analysis exhibits increased bioelectrical activity in the range of 8 to 30 c/s with no substantial changes in slower rhythms. The effect increases as the field becomes stronger. A SMF of 1000 Oe tends to facilitate the photic driving which persists as an after-effect. In SMF of 3000 Oe the driving reaction is weakened; it is rapidly restored after cessation of the SMF action.

[Detection of viral-bacterial factors responsible for infertility in couples]. / Vyiavlenie spektra virusno-bakterial'nykh faktorov, indutsiruiushchikh besplodie u supruzheskikh par.

A high prevalence of genital infections was revealed in patients suffering for a long time from sterility. The inflammatory process was found to predominate in tubal sterility. In other forms of sterility with asymptomatic urogenital infections the couples are frequently unaware of the disease and are not properly examined. Genital inflammations not diagnosed for many years augment the endocrine disorders and stimulate the development of autoimmune states. Today, a mixed viral/bacterial urogenital infection is the principal cause of reproductive disorders.

[The role of macrophage suppressor activity in the mechanism of metastasis after tumor resection]. / Rol' makrofagov s supressornoi aktivnost'iu v mekhanizme stimuliatsii metastazirovaniia posle rezektsii opukholi.

The rates of spontaneous metastasis to the lung (SML) and lymph nodes, cytotoxic and antimetastatic activity (AA) of macrophages in the course of and after resection of transplantable mammary adenocarcinoma MMTI as well as cloned tumor MMTv4 were studied in C3Hf mice. Murine macrophages showed AA in adoptive test in the course of MMTv4 growth and specific cytotoxic activity in tests in vitro. Macrophages from bearers of MMTv4 revealed non-specific cytotoxicity only. After tumor resection, a sharp increase in SML and metastasizing into lymph nodes was matched by a lack of AA and cytotoxic activity on the part of macrophages in mice operated on. In tumor cell recipients, they were found to stimulate metastasis formation. Only 60% of operated mice survived and macrophages obtained from them did not reveal any metastasis-stimulating activity. This activity was further curbed due to injections of indomethacin--an inhibitor of prostaglandin E2 synthesis--or as a result of indomethacin pretreatment of macrophages in vitro. The above data implicate suppressor activity in the explosion of metastatic formation observed after tumor resection. The role of macrophage suppressors and that of of prostaglandin E2 in postsurgical stimulation of metastasis spreading are discussed.

[137-Cs levels in biliary and urinary tract organs of inhabitants of the Vitebsky Region who died in 2000-2001]. / Soderzhanie 137-Cs v organakh gepatobiliarnoi i mochevydelitel'noi sistem u umershikh v 2000-2001 gg. zhitelei Vitebskoi oblasti.

Elevated Cs levels in the liver, gall bladder, kidney and urinary bladder were identified by gamma-spectral assay in the victims of common and oncological pathologies who died in Vitebsk Region in 2000-2001. The nuclide concentrations were relatively higher in gall and urinary bladder tissues in both groups. No differences in Cs uptake were established.

[Distribution of Cs-137 in the human body with malignant neoplasms of various localizations]. / Raspredelenie 137-Cs v organizme cheloveka pri zlokachestvennykh novoobrazovaniiakh razlichnykh lokalizatsii.

137Cs-concentrations and distribution in internal organs and malignant tumor tissues from cadavers and patients operated on for cancer were identified by gamma spectrometry in clinics of Vitebsk Region. Non-uniform distribution patterns in different organs were registered, irrespective of the presence or absence of malignancy.

Interferon stimulated genes, CXCR4 and immune cell responses in peripheral blood mononuclear cells infected with bovine viral diarrhea virus.

Non-cytopathic bovine viral diarrhea virus (ncpBVDV) induces immune responses mediated by chemokines and interferon (IFN) stimulated genes (ISGs). Cultured bovine peripheral blood mononuclear cells (PBMC) from ncpBVDV-naïve cattle were used herein to demonstrate that BVDV infection modulates chemokine receptor 4 (CXCR4), CXCL12, IFN-I, ISGs and selected immune cell marker (CD4, CD8, CD14) mRNAs, and that these acute responses to viral infection are reflected in PBMC cultured with serum from heifers carrying fetuses persistently infected (PI) with ncpBVDV. Infection of PBMC with ncpBVDV increased IFN-ß, ISG15, RIG-I, CXCR4, CXCL12, and CD8 mRNA concentrations after 32 h. Culture of PBMC with uterine vein serum from acutely infected heifers, inoculated with ncpBVDV during early gestation to generate PI fetuses, also increased the concentration of CXCR4, RIG-I and ISG15 mRNAs. In vitro PBMC treatment with ncpBVDV or uterine vein serum from acutely infected pregnant heifers activates chemokine, ISG and immune cell responses.

The brain 5-HT1A receptor gene expression in hibernation.

Hibernation is a unique physiological state characterized by profound reversible sleep-like state, depression in body temperature and metabolism. The serotonin 5-hydroxytryptamine(1A) (5-HT(1A)) receptor gene sequence in typical seasonal hibernator, ground squirrel (Spermophilus undulatus), was specified. It was found that the fragment encoding the fifth transmembrane domain showed 93.6% of homology with the analogous fragment of the mouse and rat genes and displayed 88.5% homology with the human 5-HT(1A) receptor gene. Using primers designed on the basis of obtained sequence, the expression of 5-HT(1A) receptor gene in the brain regions in active, entering into hibernation, hibernating and coming out of hibernation ground squirrels was investigated. Significant structure-specific changes were revealed in the 5-HT(1A) messenger RNA (mRNA) level in entry into hibernation and in arousal. An increase in the 5-HT(1A) gene expression was found in the hippocampus during the prehibernation period and in ground squirrels coming out of hibernation, thus confirming the idea of the hippocampus trigger role in the hibernation. Significant decrease in 5-HT(1A) receptor mRNA level in the midbrain was found in animals coming out of hibernation. There was no considerable changes in 5-HT(1A) receptor mRNA level in different stages of sleep-wake cycle in the frontal cortex. Despite drastically decreased body temperature in hibernating animals (about 37 degrees C in active and 4-5 degrees C in hibernation), 5-HT(1A) receptor mRNA level in all examined brain regions remained relatively high, suggesting the essential role of this 5-HT receptor subtype in the regulation of hibernation and associated hypothermia.

[Variation pulsimetry in evaluating the effect of permanent magnetic fields on cardiac activity]. / Variatsionnaia pul'sometriia v otsenke vliianiia postoiannykh magnitnykh polei na serdechnuiu deiatel'nost'.

By variation pulsimetry changes in the cardiac rhythm of 30 rats exposed to a constant magnetic field (CMF) were examined. Three stages different in statistical parameters were distinguished: transient process when the electromagnet is turned on; shift of variation curves of the cardiac intervals to the right and development of bradycardia during exposure to CMF of 0.4 T (10-30 min) and 1.6 T (3 h); adaptation and rearrangement of the cardiac rhythm towards a higher frequency during and after 24 h exposure to CMF of 1.6 T. In some cases atropine prevented bradycardia during CMF exposure. In most rats under nembutal anesthesia the exposure caused an opposite effect, i.e. shift of variation curves of the cardiac intervals to the left and increase in heart rate.

[Effect of corazole in intensifying changes in the electrical activity of the brain in a constant magnetic field]. / Usilenie izmeneii bioélektricheskoi aktivnosti mozga v postoiannom magnitnom pole pod vliianiem korazola.

Corazol effects on the background and evoked biopotentials of the cerebral cortex, hypothalamus, and the cerebellar cortex were studied in rats exposed to a constant magnetic field (500, 1000, 4000 Oe). After the corazol pretreatement with subconvulsive doses there were sharp changes in the background rhythms; evoked potentials of the amplitude rose markedly, and there was also an increase of additional phases in its structure. Intensification of the constant magnetic field effect against the background of analeptic corazol action pointed to the importance of the central nervous system activation level in the response to the magnetic field action.