Biomedical subjects
Publications and source records attributed to S V Popov.
We demonstrate an ytterbium gain band self-induced modulation instability laser. A highly nonlinear holey fiber is used to provide the anomalous dispersion required for bright soliton generation at 1 microm. The all-fiber integrated source yields a 40 GHz train of 4 ps pulses at a wavelength of 1064 nm.
Galacturonan, the main constituent of the backbone (core) of the comaruman macromolecule, a pectin from the marsh cinquefoil Comarum palustre L., was obtained on partial acid hydrolysis of the pectin. Using atomic force microscopy and methylation analysis of the galacturonan, the backbone of the comaruman macromolecule was shown to contain branches as side chains consisting of alpha-1,4-linked residues of D-galactopyranosyl uronic acid attached to the 2- and 3-positions of the galacturonic acid residues of the core, in addition to linear regions of alpha-1,4-D-galacturonan. A few side chains appear to attach to 2,3-positions of the D-galacturonic acid residues.
The subjects of the study were 64 patients with coronary heart disease, atherosclerotic cardiosclerosis, constant atrial fibrillation, and total artificial atrioventricular blockade corrected by means of electrocardiostimulation, complicated by non-massive pulmonary arterial thromboembolism. Twenty-one patients had lowered arterial oxygen partial pressure, (paO2 whereas in 15 patients this variable was increased; both conditions were associated with vestibuloatactic and asthenic syndromes, as well as cognitive function decrease. The presence of sympathicotonia in 93% of the patients with increased paO2 made it possible to describe hyperventilation syndrome, which had not been described before and which takes place in cases of constantly relapsing non-massive embolization of pulmonary artery's small branches, associated with endocardial electrocardiostimulation.
AIM: To study efficacy and safety of transplantation of bone marrow autologous mononuclear cells (BMAMC) in patients with acute myocardial infarction; to examine BMAMC distribution in the human body after intracoronary introduction. MATERIAL AND METHODS: The open controlled trial investigated 26 AMI patients (16 entered the study group and 10 were controls). Cell cardiomyoplasty with BMAMC was performed by intracoronary injection of the cells after stenting the coronary artery supplying blood to the infarction zone on AMI day 7-21. BMAMC were isolated by gradient centrifugation. Distribution of mononuclear cells was studied with radionuclear indication of the cells 99m-Tc-HMPAO. All the patients were examined with Tl-199 perfusion scintigraphy of the heart 2 weeks and 6 months after the treatment, echocardiography, 24-h ECG monitoring, 6-min walk test. RESULTS: All the patients were followed up for 6 months. Two patients (one in each group) developed recurrent myocardial infarction 3 months after the first. Radionuclide investigations revealed fixation of labelled mononuclear cells in the heart both in initial hours after the treatment and 24 hours after it. As shown by myocardial scintigraphy, intracoronary administration of the cells with short-term arterial occlusion was followed by much greater number of labeled cells. By follow-up month 6, in the study group, left ventricular ejection fraction increased more: 12.7 +/- 3.2% versus 10.4 +/- 2.5% in the control group (p = 0.09); moreover, a stable defect of myocardial perfusion reduced more (by 29 +/- 24% against 20 +/- 18%, respectively, p = 0.1). Malignant arrhythmia, complications during and after bone marrow aspiration, intracoronary administration of cell suspension were not registered. CONCLUSION: Intracoronary administration of BMAMC in AMI patients is safe and provides their transfer and fixation in the myocardium. BMAMC transplantation has a positive effect on recovery of perfusion and contractile function of left ventricular myocardium in AMI patients.
The authors presented results of single-stage cross study of randomized select from a cohort of long seniority workers of isotope separation plant in Siberian Chemical Enterprise, with studies of inflammation markers, vascular and platelet hemostasis, serum lipid parameters, calculated atherogeneity coefficient, homocysteine levels. Serum atherogeneity coefficient and inflammation markers levels (fibrinogen, C-reactive protein) could be considered as the most informative laboratory indicators of underlying cardiovascular diseases in individuals without ischemic heart disease. Among a list of standard inductors of platelet aggregation, collagen and epinephrine should be considered preferential. Increased platelet aggregation requires disaggregant therapy, especially in smokers. Increased homocysteine level is associated with high frequency of atherosclerotic plaques and smoking.
By combining multiple photonic crystal fibers with sequentially decreasing zero-dispersion wavelengths we have produced a 1.2 W average-power white-light continuum, covering the visible-near-infrared spectrum from 0.44 to 1.89 microm (10 dB width), with an all-fiber picosecond ytterbium pump laser. Wavelengths as short as the ultraviolet (0.35 microm), and spectral power densities of more than 2 mW/nm in the blue spectral region, have been generated. The process is understood in terms of optimizing four-wave mixing phase matching to enhance short-wavelength generation.
We generated 0.66 microm picosecond pulses by second-harmonic generation of the Raman amplified output of a 1.3 microm actively mode-locked fiber ring laser in a periodically poled potassium titanyl phosphate (PPKTP) waveguide. The ring laser produced 9 ps pulses at a 20 GHz repetition frequency, was tunable over 1284-1330 nm, and was based on a semiconductor optical amplifier and a Mach-Zehnder amplitude modulator. The Raman amplifier served both to amplify the ring laser and to compress the pulses as solitons. The spectral flexibility of the amplifiers and the modulator should enable similar configurations to be made at other wavelengths and facilitate efficient frequency doubling in waveguides to other visible wavelengths.
We report on the development of a 2.5 microm core photonic crystal fiber with a substantially reduced water-peak loss around 1.38 microm, which allows extended Raman-soliton supercontinuum generation up to 1.55 microm with a cw ytterbium fiber laser pump source. The resulting broadband, high-spectral-power-density, low-coherence light source can be employed for advanced, submicrometer resolution optical coherence tomography.
We demonstrate an ultrashort all-fiber-integrated chirped-pulse amplification system yielding 1-ps pulses with 20 kW of peak power. 40-ps initial pulses generated by an externally modulated laser diode are chirped by self-phase modulation in a conventional fiber, amplified, and compressed in 110 m of air-core photonic bandgap fiber. The compressed pulses are frequency doubled in a periodically poled KTP crystal with up to 48% efficiency and applied to supercontinuum generation in a holey fiber, resulting in a high-power uniform continuum that stretches from 430 to 1450 nm.
The pectic polysaccharide named bergenan BC was obtained using extraction of the green leaves of Siberian tea Bergenia crassifolia (L.) Fritsch. by an aqueous ammonium oxalate. The polysaccharide obtained was proved to comprise mainly d-galacturonic acid, galactose, rhamnose, arabinose and glucose residues and appeared to be pectin. Delayed type hypersensitivity (DTH) reaction to aggregated ovalbumin (agOVA) was found to increase in mice that received bergenan solution (2 mg/mL) for 3 weeks. Bergenan BC was observed to enhance the uptake capacity of human neutrophils at a concentration 100 microg/mL and to stimulate the generation of oxygen radicals by mouse peritoneal macrophages in vitro. Bergenan BC was found to increase the spontaneous adhesion of peritoneal leukocytes and failed to influence adhesion stimulated by PMA or adhesion of peritoneal leukocytes incubated in the presence of 5 mm EDTA. Bergenan failed to show cytotoxic action. The viability of peritoneal leukocytes was estimated to be equal to 91% +/- 8% and 90% +/- 7%% in the control and in the pectin solution at a concentration of 1 mg/mL.Thus, bergenan was shown to possess immunostimulating activity in relation to DTH response in vivo and phagocytic activity in vitro.
A simple, economic, and sparing method for isolation of cardiomyocytes from adult rat heart is proposed. Ultrastructure of cardiomyocytes from suspension of freshly isolated cells was studied by light and transmission electron microscopy. The isolated cardiomyocytes were viable, had characteristic shape and size, and retained their normal structure.
Experimental atrial fibrillation in intact rats significantly decreased the content of catecholamines in atrial adrenergic fibers and phosphorylase activity, which attests to enhanced glycogen consumption in the heart. These changes were specific of the fibrillating myocardium and atria, but were absent in the ventricles. Induced atrial fibrillation did not modify activities of SDH and monoamine oxidase in cardiac subdivisions. It was hypothesized that increased energy requirements in the atria during myocardial fibrillation led to activation of anaerobic metabolism.
A randomized controlled study included 44 patients with acute myocardial infarction. It was found that intracoronary injection of bone marrow mononuclear cells is safe, ensures fixation of the injected cells in the myocardium, reduces blood levels of IL-1beta and TNF-alpha, increases the content insulin-like growth factor, and does not provoke malignant arrhythmias.
A pectic polysaccharide named comaruman (CP) was extracted from the aerial part of Comarum palustre with 0.7% aqueous ammonium oxalate and subsequent precipitation with ethanol. Oral administration of comaruman (5-100 mg/kg) was found to reduce a paw edema observed 24 h after injection of 2% formalin in mice. A fraction of comaruman (CP-H9) exhibited a similar antiinflammatory activity. Comaruman, CP deprived of lipid, CP purified by proteins and CP fractions obtained with acidic hydrolysis inhibit spontaneous and phorbol-12-myristate-13-acetate-activated adhesion of peritoneal leukocytes in vitro.
Earlier, we detected antiinflammatory action of comaruman, pectin of the marsh cinquefoil Comarum palustre L. This effect can be explained by new data concerning inhibition of adhesion of human neutrophils to fibronectin by comaruman and its fragments. The galacturonan backbone fragment of molecular mass >10 kD appears to be the active region of the comaruman macromolecule. Comaruman CP (50-200 microg/ml) was found to decrease adhesion of neutrophils stimulated by phorbol 12-myristate 13-acetate (PMA, 1.625 microM) and by dithiothreitol (DTT, 0.5 mM). The fragments of comaruman CP-H (100 kD), CP-H1 (10-50 kD), and CP-H2 (100 kD) obtained by acidic hydrolysis and representing regions of linear polygalacturonan are shown to inhibit neutrophil adhesion more than the crude pectin. A fragment CP-E (<10 kD) obtained using pectinolysis and representing a branched region of the comaruman macromolecule failed to influence cell adhesion. The parent comaruman CP as well as fragments of its polygalacturonan backbone diminish PMA-initiated generation of oxygen radicals in neutrophils.
Ability of mononuclear and adhesive cells to form differentiated elements of various tissues and organs in tissue culture in vitro has been studied in experiments on CBA mice. It has been established that adhesion mesenchymal stem cells are present in bone marrow. These cells are able to generate muscular, nervous, endothelioid, epithelioid, reticular, fibroblastoid, chondrogenic, osteogenic, and other types of cells. Mesenchymal islets have been frequently found both as parts of colonies and as independent units. Potential developmental flexibility of mesenchymal cells allows to suppose their high efficacy in pathogenetic cell therapy of heart diseases when besides damaged muscular elements vascular and nervous elements should be also restored. Mononuclear cells have not demonstrated this ability. They formed mainly monocyte-macrophagal and lymphoid cells.
AIM: To study effect of amiodarone on inotropic reactions of myocardium of patients with ischemic heart disease and rats. METHODS AND RESULTS: Excitability of rat myocardium has been found to be higher than that of myocardium of patients. Sarcoplasmic reticulum of myocardium of rats has greater functional reserve, therefore rat muscle preparations respond to extrasystolic stimuli with postextrasystolic potentiation. Perfusion with a solution containing amiodarone caused diminution of amplitude of extrasystolic response of muscular strips both from rats and patients. Amiodarone augmented ability of sarcoplasmic reticulum to accumulate Ca ions as it prevented decrease of postextrasystolic contraction of human myocardium and brought about postextrasystolic potentiation of muscular strips of rat myocardium. CONCLUSION: Amiodarone affected intracellular homeostasis of calcium ions in cardiomyocytes of both rats and patients. Amiodarone lowered myocardial excitability and facilitated ability of cardiomyocyte sarcoplasmic reticulum to accumulate calcium ions.
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