Infrared luminescence in bismuth-doped AgCl crystals

Experimental and computer-modeling studies of the spectral properties of crystalline AgCl doped with metal bismuth or bismuth chloride are performed. The broad near-IR luminescence band in the 0.8-1.2 μm range with time dependence described by two exponential components corresponding to the lifetimes of 1.5 and 10.3 μs is excited mainly by 0.39-0.44 μm radiation. Computer modeling of probable Bi-related centers in the AgCl lattice is performed. On the basis of experimental and calculation data, a conclusion is drawn that IR luminescence can be caused by Bi+ ion centers substituted for Ag+ ions.

Centers of near-IR luminescence in bismuth-doped TlCl and CsI crystals

A comparative first-principles study of possible bismuth-related centers in TlCl and CsI crystals is performed and the results of computer modeling are compared with the experimental data. The calculated spectral properties of the bismuth centers suggest that the IR luminescence in TlCl:Bi is most likely caused by Bi(+)···V(Cl)(-) centers (Bi(+) ion in thallium site and a negatively charged chlorine vacancy in the nearest anion site). On the contrary, Bi(+) substitutional ions and Bi(2)(+) dimers are most likely responsible for the IR luminescence in CsI:Bi.

Near-infrared luminescence in TlCl:Bi crystal

Experimental and theoretical studies of spectral properties of crystalline TlCl:Bi are performed. Two broad near-infrared luminescence bands with a lifetime of about 0.25 ms are observed: a strong band near 1.18 μm excited by 0.40, 0.45, 0.70, and 0.80 μm radiation and a weak band at ≳1.5 μm excited by 0.40 and 0.45 μm radiation. Computer modeling of Bi-related centers in TlCl lattice suggests that a Bi(+)…VCl(Cl)(-) center (Bi(+) in Tl site and a negatively charged Cl vacancy in the nearest anion site) is most likely responsible for the IR luminescence.

[Changes of content of regulatory lymphocytes and concentration of soluble interleukine-2 receptor in blood of patients with ischemic heart disease after coronary artery angioplasty with implantation of stents with rapamycin covering]

We studied dynamics of content of subpopulation of lymphocytes including regulatory and effector T-lymphocytes as well as concentration of soluble form of interleukine-2 receptor (sCD25) in peripheral blood of patients after coronary stenting (CS) with implantation of stents with rapamycin covering (SRC). We included into the study 62 patients with stable effort II-III functional class angina. Coronary angiography (CA) was carried out in all, CS with implantation of 1 - 2 SRC - in 42 patients. Blood samples were taken before CA/CS, in 24, 48 hours, 7 days, 1 and 3 months after intervention. Content of T-, helper and cytotoxic T-cells, -, NK-, NKT-cells, activated effector T-lymphocytes (CD4+CD251owCD127high) and regulatory T-lymphocytes (CD4+CD25highCD1271ow) were measured by direct immunofluorescence and flow cytometry. CD4+ lymphocytes were isolated from mononuclear cell fraction of donor blood by magnetic separation. Content of regulatory T-lymphocytes in culture were determined by expression of a specific marker FOXP3+. Concentration of sCD25 was measured by chemiluminescent method. It was shown that content of main subpopulations of lymphocytes in blood changed after CS or CF. Blood content of regulatory T-lymphocytes and sCD25 significantly increased after 7 days and 1 month after CS but not after CA. Plasma sCD25 concentration correlated with content of regulatory T-lymphocytes in 1 month after SRC implantation. During cultivation of CD4+ lymphocytes in the presence of rapamycin we noted antiproliferative effect relative to FOXP3-cells and accumulation of regulatory +-lymphocytes. Thus implantation of SRC in coronary arteries leads to increase of number of circulating regulatory T-lymphocytes and blood concentration of sCD25. Changes of these parameters after CS can reflect peculiarities of local and systemic reaction arising in response to introduction of stent with drug covering and be significant for assessment of prognosis of the disease.

Expression of markers of regulatory CD4+CD25+foxp3+ cells in atherosclerotic plaques of human coronary arteries

The content of marker foxp3 of regulatory T cells and chemokines in atherosclerotic plaques of human coronary arteries was measured by the polymerase chain reaction. In vitro migration of regulatory CD4(+)CD25(+)foxp3(+) cells in the CD4(+) lymphocyte population from healthy donors was studied after treatment with chemokines I-309, IP-10, and SDF-1. mRNA for the factor foxp3 and chemokines SDF-1, I-309, and MIP-1beta were found in the majority of samples from atherosclerotic plaques. SDF-1 induced maximum migratory response of CD4(+)CD25(+)foxp3(+) cells.

Effects of synthetic monocyte chemotactic protein-1 fragment 65-76 on neointima formation after carotid artery balloon injury in rats

The effects of the synthetic monocyte chemotactic protein-1 (MCP-1) peptide fragment 65-76 (peptide X) on the development of neointima after balloon injury to the carotid artery were studied. The agent was given i.m. at a dose of 33 microg/kg once daily for 28 days after balloon injury. Animals given peptide showed significant suppression of neointima growth 4 and 7 days after lesioning, as indicated by morphometric analysis of sections of lesioned arteries. On days 14 and 28, there were no significant differences in neointima formation in rats given and not given peptide. Peptide administration was not accompanied by any changes in C-reactive peptide concentrations, leukocyte counts, or the population composition of peripheral blood lymphocytes. Use of synthetic peptide X as an inhibitor of leukocyte migration during angioplasty may, along with traditional treatments, decrease the risk of restenosis.

[The influence of coronary stenting with rapamycin-eluting stents on the number of circulating CD4+CD25high+regulatory T-cells]

AIM

To investigate the effects of coronary stenting with rapamycin-eluting stents on parameters of cell immunity.

METHODS

26 patients (group 1) with stable coronary heart disease and angiographically proved coronary stenosis underwent stenting with rapamycin-eluting stents. The control group (group 2) consisted of 6 patients: 4 patients underwent diagnostic coronaroangiography, I patient got a bare metal stent and in 1 patient angioplasty was unsuccessful. Blood samples were obtained before and 1 month after the intervention. The quantity of activated (CD4+CD25low+) and regulatory (CD4+CD25high+) T cells was measured by direct immunofluorescence and flow cytometry. Plasma concentration of IL-10 was determined by ELISA.

RESULTS

In group 1 the percentages of CD4+CD25high+ regulatory T-cells increased significantly one month after stenting, while in group 2 no difference in regulatory T-cell levels before and after the intervention was observed. No changes in total number of leukocytes, relative levels of lymphocytes, CD4+ T-cells, activated CD4+CD25+low T-cells and IL-10 plasma concentration before and after the procedure were detected in both groups.

CONCLUSION

Rapamycin-eluting stent implantation is associated with a significant increase of circulating CD4+CD25high+ regulatory T-cell level.

Origin of broadband near-infrared luminescence in bismuth-doped glasses

Interstitial negative-charged bismuth dimers, Bi(-)(2) and Bi(2-)(2), are suggested as a model of broadband IR luminescence centers in bismuth-doped glasses. The model is based on quantum-chemical calculations of equilibrium configurations, absorption, luminescence, and luminescence excitation spectra of the dimers in an alumosilicate network and is supported by IR luminescence observed for the first time, to our knowledge, in bismuth-doped polycrystalline magnesium cordierite.

[The effect of synthetic fragment 65-76 of monocyte chemiattractant protein-1 (MCP-1) on neointima growth after carotid artery balloon injury in rats]

Influence of synthetic fragment 65-76 of monocyte chemoattractant protein-1 (MCP-1) (peptide X) on development of neointima after balloon injury of carotid artery was investigated. Peptide X was introduced intramuscularly, 33 pg/kg, daily during 28 days after balloon injury. In days 4 and 7 after intervention, in animals receiving peptide X in comparison with control animals a substantial decrease of neointimal growth was observed. On 14 and 28 days there, was no significant difference in neointima development in rats with and without peptide treatment. Injections of peptide X did not after the C-reactive protein concentration, leukocyte number and lymphocyte subpopulations in peripheral blood. Peptide X treatment along with traditional therapy may be effective in preventing restenosis after angioplasty.

Raman band intensities of tellurite glasses

Raman spectra of TeO2-based glasses doped with WO3, ZnO, GeO2, TiO2, MoO3, and Sb2O3 are measured. The intensity of bands in the Raman spectra of MoO3-TeO2 and MoO3-WO3-TeO2 glasses is shown to be 80-95 times higher than that for silica glass. It is shown that these glasses can be considered as one of the most promising materials for Raman fiber amplifiers.

UV-irradiation-induced structural transformation in phosphosilicate glass fiber

The Raman spectra of phosphosilicate core (P(2)O(5)-SiO(2)) fibers were investigated. Significant changes in the spectra were observed after UV irradiation of the fibers. An interpretation of the photostructural changes confirmed by computer simulation of phosphorus-related centers is proposed.

[Role of extra-intracarotid anastomosis in the surgical treatment of chronic cerebral ischemia]

About 500 patients with ischemic brain lesions were studied. Out of them 201 patients underwent 230 operations: 140 extra-intracarotid bypass (EIB) and 90 various interventions on brachiocephalic branches. The study of cerebral hemodynamics by examining blood pressure in the central artery of the retina and middle cerebral artery during surgery, comparison of these findings with those of Doppler sonography and angiography made the authors conclude that EIB improves cerebral hemodynamics, and in some cases it is the only intervention able to improve the status of patients. In severe disseminated atherosclerosis with occlusion of one of the carotid arteries, EIB should follow other interventions on brachiocephalic branches. EIB was found to make the natural history of cerebral failure steady in 80.3%.