Aspects of "antigen-antibody" interaction of chicken infectious bronchitis virus determined by surface plasmon resonance.

Authors performed investigation on "antigen-antibody" interaction of chicken infectious bronchitis coronavirus (IBV) by a method based on the surface plasmon resonance (SPR). Presence of space-size effect related to a difference between antigen and antibody particle sizes has been theoretically grounded and experimentally proven. Herewith, the difference between responses of the SPR-sensor to specific and non-specific interactions is considerably less (up to 6.3 times) than the expected one (8 - 11 times). An impact of functionalization of sensor's sensitive element surface, as well as acidity of buffer solution on the activity of antigen-antibody interaction was studied here. The difference between sensor's responses to specific and non-specific interactions increased two-fold from 200 to 432ang sec due to this treatment. When changing the acidity of analyzed solution from pH7.3 to pH6.8, the corresponding difference between sensor's responses increased by 6.3 times from 194 up to 1235ang.sec. Thus, an impact of space-size effect on interaction between IBV antigen and specific antibody can be considerably (almost in 3 times) decreased by reducing the acidity of used buffer solution. The results of our investigation can be successfully applied to develop new methods for detection of pathogens and specific antibodies using SPR.

First main series of transition elements with atomic numbers from 22 to 29, found in air pollution and detected in the plants from Tajikistan areas.

According to several reports, the presence of transition metal elements in the atmosphere was associated with adverse health effects. The purpose of this investigation was to analyze the presence of transition metal particles with atomic numbers 22-29 on some medicinal plants (n = 22) from various regions of the Republic of Tajikistan and their content in the atmosphere. Samples (n = 43) of individual plant organs, such as seeds, flowers, leaves, trunks, and plant roots, were examined for their elemental composition using X-ray fluorescence analysis. Selection of particles contained in the atmosphere was carried out for 24 h/3 days by the aspiration method using fiberglass filters GF 10 in an apparatus installed at an altitude of 864 m on the periphery of the capital. For the analysis of plant samples, measurements were carried out on a SPECTROSCAN MAX-G wave-dispersive X-ray fluorescence spectrometer. For samples containing filtered atmosphere elements, a high-resolution PANanalytical Epsilon 5 high-resolution energy-dispersive spectrometer was used. Eight transition elements from the 1st main series of metals with atomic numbers 22-29, such as titanium, vanadium, chromium, manganese, iron, cobalt nickel, and copper, were found in plant organs, as well as in the atmosphere samples. Our results showed that the distribution of metals on plants varied depending on plants and their organs. We did not find any correlation between the region of plant collection and their absorption of metal elements. The distribution of metals varied in various plant organs. In the atmosphere samples, we found all the metals that were found in plants. In conclusion, medicinal plants can adsorb and accumulate some harmful chemical elements in their organs, are involved in the recirculation of these metals, and contribute air pollution.

Chitosan nanocomposites with CdSe/ZnS quantum dots and porphyrin.

Water-soluble nanocomposites based on CdSe/ZnS quantum dots (QDs) and hydrophobic tetraphenylporphyrin (TPP) molecules passivated by chitosan (CS) have been formed. Magnetic circular dichroism (MCD) spectra evidence TPP presence in both monomeric and agglomerated forms in the nanocomposites. The nanocomposites demonstrate more pronounced singlet oxygen generation compared to free TPP in CS at the same concentration due to the intracomplex Förster resonance energy transfer (FRET) with a 45% average efficiency.

Characteristics of BENZOPYRAN Laser Dyes in Annealed Silica XEROGEL.

The spectroscopic and laser characteristics of two benzopyrane derivatives for 600-670 nm spectrum region of lasing in preliminarily annealed silica xerogel matrices in non-selective cavity under laser pumping at 551 nm have been measured and analysed. The influence of molecular structure of the dyes on their non-radiating losses has been revealed. The specific output laser energy of the studied matrices was approximately equal to the ones for corresponding methanol solutions under the same pumping conditions. The laser spectra of the matrices were displaced to the red region from the fluorescence maximum by about 1000-1500 cm-1 in a nonselective cavity. Such spectral displacement may improve the characteristics of biosensors made on the basis of these matrices because it shifts their emission spectrum to the range of deeper penetration into biological tissues.

Enantioselective cellular uptake of chiral semiconductor nanocrystals.

The influence of the chirality of semiconductor nanocrystals, CdSe/ZnS quantum dots (QDs) capped with L- and D-cysteine, on the efficiency of their uptake by living Ehrlich Ascite carcinoma cells is studied by spectral- and time-resolved fluorescence microspectroscopy. We report an evident enantioselective process where cellular uptake of the L-Cys QDs is almost twice as effective as that of the D-Cys QDs. This finding paves the way for the creation of novel approaches to control the biological properties and behavior of nanomaterials in living cells.

Chlorin e6-ZnSe/ZnS quantum dots based system as reagent for photodynamic therapy.

Stable water-soluble complexes of Cd-free ZnSe/ZnS quantum dots (QDs) and chlorin e6 complexes have been prepared. These complexes have shown approximately 50% intracomplex fluorescence resonance energy transfer from QDs to chlorin e6. The photodynamic therapy (PDT) test of the complexes against the Erlich acsite carcinoma cell culture demonstrated a two-fold enhancement of the cancer cell photodynamic destruction as compared to that of free chlorin e6 molecules. It was shown that the PDT effect was significantly increased due to two factors: the efficient QD-chlorin e6 photoexcitation energy transfer and the improvement of cellular uptake of the photosensitizer in the presence of ZnSe/ZnS QDs.

[Focal nodular liver hyperplasia].

It was evaluated the frequency of focal nodular liver hyperplasia and treatment resultsin 1425 patients for the last 17 years in 2 time period. The own experience and literature data were used. First this disease was considered as very rare liver tumor because of underdeveloped diagnostics. Tumor detection was the indication for laparotomy. In some patients removal of the tumor was not performed if intraoperativebiopsy has shown tumor benign. The indication for dynamic observation and surgical treatment were identified with increasing number of patients, diagnostics improvement, and analysis of immediate and long-term results. The operation provides persistentcure.

[Pretective action of peptide pro-gly-pro on electrophysiological characteristics of cultured hippocampal neurones during excitotoxic damage].

Electrophysiological characteristics of hippocampal neurones cultured with Pro-Gly-Pro peptide were studied using glutamate excitotoxisity model (excitotoxic damage was induced by 100 mkM glutamate application during 5 min). It was found that negative changes in neurones cultured with 10 mcM Pro-Gly-Pro were less prominent if compared with control ones. Culturing with the peptide significantly affected the following parameters: resting potential (-55 +/- 4 mV in control; -29 +/- 6 MV after glutamate application; -38 +/- 5 MV cultured after glutamate application), action potential amplitude (91 +/- 4; 65 +/- 5; 84 +/- 5 mV), duration (4,3 +/- 0,4; 9,5 +/- 1,6; 5,2 +/- 0,7 ms), depolarization (56 [38, 84]; 27 [21, 35]; 46 [28, 62] MV/Ms) and repolarization (-29 [-38, -27]; -20 [-21, -18]; -29 [-33, -22] M(V)/MS) rates. The data obtained suggest that PGP exhibit its neuroprotective properties on a level of basic electrophysiological characteristics, appropriate cellular mechanisms require further investigations.

[Electrical properties of retinal ganglion cells of rats with streptozotocine-induced diabetes].

On isolated retinal preparation from STZ-induced diabetic rats in whole-cell configuration the basic electrical properties of retinal ganglion cells (RGC) were studied. It was shown that on 8th week after STZ maximal depolarization-induced firing frequency is reduced and decay time constant of high-frequency stimulation-induced calcium signals is increased as compared to controls. The data obtained suggest functional changes in RGC of STZ-induced diabetic rats, possible mechanisms of such changes are discussed.

Reversible photoluminescence quenching of CdSe/ZnS quantum dots embedded in porous glass by ammonia vapor.

The photoluminescence response of semiconductor CdSe/ZnS quantum dots embedded in a borosilicate porous glass matrix to exposure to ammonia vapor is investigated. The formation of surface complexes on the quantum dots results in quenching of the photoluminescence and a shortening of the luminescence decay time. The process is reversible, desorption of ammonia molecules from the quantum dot surface causes the photoluminescence to recover. The sensitivity of the quantum dot luminescence intensity and decay time to the interaction time and the reversibility of the photoluminescence changes make the CdSe/ZnS quantum dots in porous glass system a candidate for use as an optical sensor of ammonia.

Direct mass measurements of 19B, 22C, 29F, 31Ne, 34Na and other light exotic nuclei.

We report on direct time-of-flight based mass measurements of 16 light neutron-rich nuclei. These include the first determination of the masses of the Borromean drip-line nuclei (19)B, (22)C, and (29)F as well as that of (34)Na. In addition, the most precise determinations to date for (23)N and (31)Ne are reported. Coupled with recent interaction cross-section measurements, the present results support the occurrence of a two-neutron halo in (22)C, with a dominant ν2s(1/2)(2) configuration, and a single-neutron halo in (31)Ne with the valence neutron occupying predominantly the 2p(3/2) orbital. Despite a very low two-neutron separation energy the development of a halo in (19)B is hindered by the 1d(5/2)(2) character of the valence neutrons.

Track membranes with embedded semiconductor nanocrystals: structural and optical examinations.

We studied the optical properties of poly(ethylene terephthalate) ion track membranes of 1.5, 0.5 and 0.05 µm pores impregnated with luminescent semiconductor CdSe/ZnS nanocrystals of different diameters (2.5 and 5 nm). The nanocrystals were embedded from their colloidal solutions in toluene by the immersion of a membrane in a colloidal solution. Localization of quasi-isolated weakly interacting CdSe/ZnS nanocrystals in a loosened layer on the track pore wall surface along with the existence of empty pores was demonstrated. We observed also the spatial separation of nanocrystals of 2.5 and 5 nm in size along the 50 nm pores.

[Calcium signaling induced by tonic firing in the rat eye retinal ganglion cells].

On rat retinal preparation in whole-cell mode retinal ganglion cells (RGC) tonic firing induced calcium signals were recorded and their modulation by Kv3 potassium channels was studied. RGC depolarization with 500 ms current steps caused tonic action potentials (AP) generation and development of calcium signals which amplitude depended quite linearly on mean AP frequency with mean slope 1.4 +/- 0.2 s x nmol/l (n = 5). The calcium signals mean tau of decay value was 6.8 +/- 1.4 s (n = 5). After application of tetraethylammoniun (500 MM), which in such concentration blocks Kv3.1/Kv3.2 potassium channels, a decrease in firing frequency, an increase of AP width and a decrease of afterhyperpolarization amplitude were observed. In the presence of the blocker the calcium signal amplitude vs mean AP frequency dependency slope mean value increased to 2.1 +/- 0.3 s.nmol/l. The calcium signals tan of decay not changed significantly, the mean value was 8.9 +/- 1.6 s (n = 5). Thus, voltage-dependent Kv3.1/Kv3.2 potassium channels, which play a key role in tonic firing pattern generation in RGC, also modulate appropriate calcium signals and prevent the cells from significant intracellular calcium increasing and its possible cytotoxic action.

[Effect of 4-aminopyridine-sensitive potassium current on high frequency tonic firing of the rat retinal ganglion cells].

High frequency firing properties of the rat retinal ganglion cells and role of 4-AP-sensitive potassium current in firing generation were studied using whole cell patch-clamp techniques. Potassium channel blocker 4-AP (0,2 mM) reduced depolarization-evoked firing rate by 62% (from 50 +/- 5, n = 12 to 19 +/- 2 Hz, n = 7). Single action potential parameters were affected: half-width was increased by 133% (from 1,2 +/- 0,1, n = 12 to 2,8 +/- 0,3 ms, n = 7), decay slope was decreased by 63% (from 102 +/- 11, n = 12 to 38 +/- 7 mV/ms, n = 7) and afterhyperpolarization amplitude by 83% (from 18 +/- 2, n = 12 to 3 +/- 2 mV, n = 7). 4-AP application (0,2 mM) reduced potassium current amplitude of the retinal neurons. 4-AP-sensitive current was obtained by digital subtraction of current that was registered in the presence of the blocker from control current records (1,61 +/- 0,22 nA, n = 6). 4-AP-sensitive current was equal to 0,40 +/- 0,09 nA (n = 6). Thus, moderate (25%) reducing of potassium current amplitude leads to essential changes in firing properties of retinal neurons. 4-AP-sensitive residual current was similar to Kv3.1/Kv3.2 potassium currents that were described in literature previously. Moreover, we excluded the possibility of 4-AP influence on Kv1 channels by specific blocker alpha-dendrotoxin (100 nM) application. Such applications significantly affected neither firing frequency nor single action potential parameters. The data obtained suggest that 4-AP-sensitive current plays a key role in high frequency firing generation in the rat retinal ganglion cells. We assume that the 4-AP-sensitive current is mediated by Kv3.1/Kv3.2 conductance.

[Problems and prospects of non-invasive screening for colorectal cancer].

High prevalence of colorectal cancer makes it a most serious socio-medical problem. Hence, the necessity of overall screening for prodromal changes and malignant neoplasms at the early stages of the disease. Despite a variety of efficacious instrumental diagnostic tools, the development of non-invasive screening techniques based on recent progress in understanding molecular mechanisms of carcinogenesis remains a highly topical issue. A pathogenetic model of colorectal cancer and pathophysiological basis of screening for colonic neoplasms are considered with the emphasis on the detection of tumour cells in faeces and their DNA carrying mutations in suppressor genes and oncogenes. Results of the studies with the use of one or several DNA oncomarkers are analysed in the context of their value for the diagnosis of colorectal neoplasms. High sensitivity and specificity of these methods make them very promising for application to the screening for colorectal cancer.

Comparison of Helicobacter pylori Virulence Factors, Intcrleukin-1 Polymorphisms ni Patients and Endoscopic and Histological I-indiums of Stomach and Duodenum / Шинэ санаа Шинэ нээлт

BACKGROUND The aim of the study is to detect and define the role of H. pylori virulence factors and host IL-1 polymorphisms to prevent from further gastric cancer. mwom 5ml of blood samples were collected from each of 42 patients who had abdominal complaint, after informed consent was obtained. All patients were Mongolian nationality. The biopsy specimens were stored in liquid nitrogen and homogenized before DNA isolation. After tissue lysation with proteinase K. DNA isolation was performed with "Promege" tissue kit. according to the manufacturer's instructions. PCR amplification of H. pylori gene loci was performed for the cagA gene and the vacAs mosaics vac As 1 and vacAs2. RESULTS Result of histological findings shows 84.7% from all patients were diagnosed with II. pylori infection 83% (35/42). Histologically LI'G 50% (42/21). Gastric atrophy 30% (42/13). Intestinal metaplasia 9% (42/4). Gastroduodcnal ulcer 4% (42/2), Dys¬plasia 11% (42/5), Adinocarcinoma 2% (42/1), 3 patients (42/3, 7%) were none patho¬logic change. 62% (26/42) patients infected with H. pylori, as determined by Urease test. H. pylori were investigated in all 42 patients and 83% (35/42) were infected with II. pylori, as determined by histology (haematoxylin- eosin and (iiemsa-stained). Strain characteristics of H. pylori were investigated in all 42 patients and 83% (35/42) were infected with //. pylori, as determined by UreC PCR. Result of histological findings revealed Bacilla form 48,5% (17/35), Coccoid form 28,5% (12/35), mixed form 14% (5/35) from all patients were found //. pylori. 76% (13/17) of all patients were revealed coccoid form of H. pylori were taken anti-//. pylori treatment. The vacAs 1 genotype was found in 38% (16/42) of all UreC+ patients, and cagA was found in 23% (10/42) of UreC+ patients. 16.9% of all patients were IL-RN*2 positive (7/42), (IL-1B 31C/51 IT).

[Expanded D2 lymphodissection in combined treatment of gastric cancer: unification of treatment approaches].

The authors present an analysis of results of using D2 operations in combined treatment of gastric cancer. Such volumes of operations combined with preoperative irradiation are not followed by greater number of complications and lethality. The incidence of progressing in terms more than a year proved to be considerably lower in the group of patients with combined treatment with D2 lymphodissection than in the groups without lymphodissection and preoperative radiation therapy.