Biomedical subjects

S V Morozov

Publications and source records attributed to S V Morozov.

16 recordsLinked to original sources

PubMed2006

[Drainage of the pancreatic duct].

An original drainage was used for preventing acute postoperative pancreatitis which had a construction providing preventive decompression of the pancreatic duct system acting on the pathogenetic mechanisms of its development, i.e. intraduct hypertension. The principal distinction of the proposed drainage construction is the duct system decompression with the saved physiological way of outflow of the pancreas secretion that eliminates the shortcomings of the external drainage. The drainage described was used in 6 patients after operations on the major duodenal papilla, cicatricial stricture of the papilla, choledocholithiasis. High clinical effectiveness of the method of the pancreatic duct system decompression is shown.

Adult↗

PubMed2005

Two-dimensional gas of massless Dirac fermions in graphene.

Quantum electrodynamics (resulting from the merger of quantum mechanics and relativity theory) has provided a clear understanding of phenomena ranging from particle physics to cosmology and from astrophysics to quantum chemistry. The ideas underlying quantum electrodynamics also influence the theory of condensed matter, but quantum relativistic effects are usually minute in the known experimental systems that can be described accurately by the non-relativistic Schrödinger equation. Here we report an experimental study of a condensed-matter system (graphene, a single atomic layer of carbon) in which electron transport is essentially governed by Dirac's (relativistic) equation. The charge carriers in graphene mimic relativistic particles with zero rest mass and have an effective 'speed of light' c* approximately 10(6) m s(-1). Our study reveals a variety of unusual phenomena that are characteristic of two-dimensional Dirac fermions. In particular we have observed the following: first, graphene's conductivity never falls below a minimum value corresponding to the quantum unit of conductance, even when concentrations of charge carriers tend to zero; second, the integer quantum Hall effect in graphene is anomalous in that it occurs at half-integer filling factors; and third, the cyclotron mass m(c) of massless carriers in graphene is described by E = m(c)c*2. This two-dimensional system is not only interesting in itself but also allows access to the subtle and rich physics of quantum electrodynamics in a bench-top experiment.

Journal Article↗

PubMed2005

Two-dimensional atomic crystals.

We report free-standing atomic crystals that are strictly 2D and can be viewed as individual atomic planes pulled out of bulk crystals or as unrolled single-wall nanotubes. By using micromechanical cleavage, we have prepared and studied a variety of 2D crystals including single layers of boron nitride, graphite, several dichalcogenides, and complex oxides. These atomically thin sheets (essentially gigantic 2D molecules unprotected from the immediate environment) are stable under ambient conditions, exhibit high crystal quality, and are continuous on a macroscopic scale.

Journal Article↗

PubMed2005

Hydrogenase electrodes for fuel cells.

Considering crucial problems that limit use of platinum-based fuel cells, i.e. cost and availability, poisoning by fuel impurities and low selectivity, we propose electrocatalysis by enzymes as a valuable alternative to noble metals. Hydrogenase electrodes in neutral media achieve hydrogen equilibrium potential (providing 100% energy conversion), and display high activity in H(2) electrooxidation, which is similar to that of Pt-based electrodes in sulphuric acid. In contrast with platinum, enzyme electrodes are highly selective for their substrates, and are not poisoned by fuel impurities. Hydrogenase electrodes are capable of consuming hydrogen directly from microbial media, which ensures their use as fuel electrodes in treatment of organic wastes.

Catalysis↗

PubMed2005

[Esomeprasol and rabeprasol effects on esophageal acidification in patients with gastroesophageal reflux disease, intensively metabolizing inhibitors of proton pump].

AIM: To compare action of different esomeprasol and rabeprasol doses on esophageal acidification in patients with gastroesophageal reflux disease (GERD). MATERIAL AND METHODS: A cross-over study was made in 27 GERD patients (12 males and 15 females). It included esophagoduodenoscopy with biopsy for detection of H-pylori and 24-h pH-metry of esophageal content. Rabeprasol and esomeprasol efficacy was compared for daily doses 20 mg of each (stage I) and rabeprasol 20 mg and esomeprasol 40 mg (stage II). RESULTS: All the patients proved H-pylori positive. Before the treatment mean daily time of marked esophageal acidification was 29-36%. At stage I significant differences between the drugs were absent. At stage If esomeprasol was more effective from the first day of therapy both in relation to time to effect and its intensity. CONCLUSION: Esomeprasol provided a fast and noticeable correction of esophageal acidification. This relieves symptoms of GERD and accelerates esophageal mucosa epithelization.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2005

[The role of gastroesophageal reflux in malignization of post-burn and peptic esophageal strictures].

The subjects of the study were 221 patients with cicatrical esophageal strictures. 62 (28.5%) patients had peptic strictures, and 159 (71.9%)--post-burn strictures. 67 (30.3%) patients underwent esophageal resection with one-stage intrapleural esophagoplasty with the stomach, 152 (68.8%) patients--gullet bougienage in combination with surgical intervention or as an only treatment. The study revealed 8 cases of squamous cell carcinoma in patients with post-burn strictures, and 3 cases of squamous cell carcinoma in patients with peptic strictures. In 2 cases the researchers found early stage of esophageal cancer (verrucose carcinoma)--in 1 patient with post-burn stricture and 1 patient with peptic stricture. The results suggest an important role of chronic gastroesophageal reflux in the oncogenesis of esophageal squamous cell carcinoma in patients with post-burn and peptic strictures.

Adult↗

PubMed2004

Electric field effect in atomically thin carbon films.

We describe monocrystalline graphitic films, which are a few atoms thick but are nonetheless stable under ambient conditions, metallic, and of remarkably high quality. The films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands, and they exhibit a strong ambipolar electric field effect such that electrons and holes in concentrations up to 10(13) per square centimeter and with room-temperature mobilities of approximately 10,000 square centimeters per volt-second can be induced by applying gate voltage.

Journal Article↗

PubMed2003

Antioxidant status of rats receiving lycopene in different doses.

Oral treatment with lycopene (per os) in doses of 10 or 50 mg/kg for 2 weeks led to accumulation of lycopene in the liver, liver microsomes, and blood plasma, increased total plasma antioxidant activity, inhibited LPO in the liver, and decreased solubilization of lysosomal enzymes. Lycopene had no effect on ex vivo resistance of liver microsomes to LPO and activities of antioxidant enzymes in the liver.

Animals↗

PubMed2003

Effect of lycopine on the resistance of rat liver microsomes to in vitro induced LPO.

Lycopine in concentrations of 0.5-50 microM suppressed LPO in microsomes induced by NADPH-Fe(2+) and by ascorbic acid-Fe(2+). Lycopine in a concentration of 20 microM completely prevented the decrease in the rate of benz[a]pyrene hydroxylation and activation of p-nitrophenyl-UDP-glucuronosyl transferase caused by LPO induction in microsomes.

Animals↗

PubMed2003

Effects of flavonoids on the resistance of microsomes to lipid peroxidation in vitro and ex vivo.

Incubation of rat liver microsomes with preparations of grape flavonoids, dihydroquercetin, and silibinin increased their resistance to lipid peroxidation induced by NADPH-Fe2+. This was manifested in less pronounced accumulation of lipid peroxidation products and changes in activity of microsomal enzymes induced by lipid peroxidation. In vitro antioxidant activity of grape flavonoids markedly surpassed that of dihydroquercetin and silibinin. Addition of flavonoids into fodder led to moderate, statistically significant, and similar increase in the resistance of rat liver microsomes to ex vivo induced lipid peroxidation.

Animals↗

PubMed2003

[Antisecretory therapy for prevention of stenoses of bougienage after-burn of esophageal strictures].

The purpose of the research was to study the efficacy of the bougienage of after-burn esophageal strictures against the background of long-term treatment with proton pump inhibitors of H2-blockers. 100 patients with after-burn esophageal strictures were divided into 3 groups in a random way: 1) only bougienage--53 patients; 2) bougienage and omeprazole, 20 mg per day during 12 months--20 patients; 3) bougienage and ranitidine, 300 mg per day during 12 months--27 patients. Bougienage was efficient in 83 patients (83%). 17 patients underwent esophagoplasty due to inefficiency of bougienage. Repeated bougienage was necessary for 35% of patients who were taking omeprazole (p = 0.04), 48.1%--ranitidine (p = 0.2), and 60.4% of patients who underwent only bougienage. Bougienage of the esophagus is efficient in treatment of after-burn strictures. Twelve-month treatment of these patients with omeprazole reduces the number of repeated bougienage courses significantly.

Adult↗

PubMed2003

[Comparative effectiveness of the antisecretory action of rabeprazole and esomeprazole in people with rapid metabolism of proton pump inhibitors].

AIM: To compare antisecretory effects of Rabeprazole and Esomeprazole in proton pump inhibitors extensive metabolizers in an open, randomized, two-way crossover study. METHODS: Sixteen GERD H. pylori-positive patients (8 men, mean age 49.6 and 8 women, mean age 49.3) with the homozygous extensive metabolizer genotype of CYP2C19 determined by polymerase chain reaction-restriction fragment length polymorphism analysis received Rabeprazole 20 mg or Esomeprazole 20 mg daily on days 1-6, with a 14-day wash-out period. Intragastric pH was recorded continuously on days 0, 1, 5 and 7. RESULTS: On days 1 and 5 no differences were found between Rabeprazole 20 mg and Esomeprazole 20 mg in 24-hours median pH (day 1: 5.9 versus 5.0; day 5: 6.45 versus 6.3) or in percent of time with pH 4 (day 1: 57.8% versus 50.5%; day 5: 81.4% versus 81.2%). On day 1, mean percent of time pH 4 were significantly greater after Esomeprazole 20 mg 52.6% (95% CI: 23.6-68.2) than Rabeprazole 20 mg 33.0% (95% CI: 15.3-48.2) during 0-6 h (p = 0.02). On day 7 (24 later the last dose), 24-hours median pH was higher after Esomeprazole 20 mg than Rabeprazole 20 mg (2.7 versus 5.05; p = 0.02). CONCLUSIONS: Rabeprazole 20 mg and Esomeprazole 20 mg are equally effective in increasing gastric pH in H. pylori-positive PPI extensive metabolizers on days 1 and 5. Esomeprazole 20 mg is more effective than Rabeprazole 20 mg in maintaining pH 4 during the first 6 hours on the first day and increasing of intragastric pH on the day 24 hours later the last dose.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2002

Direct and electrically wired bioelectrocatalysis by hydrogenase from Thiocapsa roseopersicina.

Hydrogen enzyme electrodes based on direct and mediated bioelectrocatalysis were developed. Direct bioelectrocatalysis of hydrogen oxidation/evolution was observed for hydrogenase adsorbed on carbon filament material. The equilibrium hydrogen potential was achieved on mediatorless hydrogen enzyme electrodes in hydrogen atmosphere. The electrocatalytic activity of hydrogenase in direct bioelectrocatalysis of hydrogen oxidation was two orders of magnitude higher compared to platinum. The reported electrode remained 50% activity after 6 months of storage with periodical testing. Wired bioelectrocatalysis was achieved by adsorption of hydrogenase onto electropolymerized redox mediator N-methyl-N'-(12-pyrrol-1-yl-dodecyl)-4,4'-bipyridinium ditetrafluoroborate.

Catalysis↗

PubMed2002

[Effect of soybean isoflavones on antioxidant status in rats fed diet with oxidized linseed oil].

The maintenance of male Wistar rats on semi-synthetic diets containing oxidized flaxseed oil for 4 weeks caused decrease in serum total antioxidant activity, significant suppression of microsomal UDP-glucuronosyl transferase activity and benzpyrene hydroxylase activity, increase in reduced glutathione level and catalase activity of liver. Supplementation of diets with 0.05% of soy isoflavones has resulted in normalization of investigated characteristics.

Animals↗

PubMed2000

Chemical composition of lipophylic compounds from the body surface of unfed adult Ixodes persulcatus ticks (Acari: Ixodidae).

Chemical compositions of ethereal extracts of the body surface of unfed male and female Ixodes persulcatus ticks (Acari: Ixodidae) were studied by gas chromatography using mass-spectrometric detection. More than 100 different organic compounds were detected. The predominant components were saturated fatty hydrocarbons, saturated and unsaturated fatty acids, aldehydes, squalene, cholesterol and cholesterol derivatives. A number of compounds found in I. persulcatus are known as components of pheromones or constituents of dermal gland secretions in tick species of the genus Amblyomma: nonanoic acid, saturated fatty acids having from 14 to 16 carbons, and squalene. Saturated fatty aldehydes have not been reported previously as body surface components of hard ticks. Substituted phenols were not found in the extracts, although they are known as common components of sex and attraction-aggregation-attachment pheromones in Amblyomma ticks. With a few exceptions (henicosanal, 2,4-holestadiene and two unidentified cholesterol derivatives), there was no marked difference in composition of surface components between male and female I. persulcatus. The possible role of the different chemical groups in communication between I. persulcatus ticks is discussed.

Aldehydes↗

PubMed1990

[Status of natural immunity and the ways of its enhancement in patients with goiter].

Disease caused by goiter is marked by changes in cellular and humoral unspecific resistance before and after operation, which at times is of decisive importance in the course of the postoperative period. Natural resistance is inhibited, to a greater measure, in patients with a long history of the disease and in those with diffuse toxic goiter. The work deals with the study of natural resistance in 98 patients with goiter before and after the operation in dynamics. The immunostimulator lysozyme was used for a more favourable course of the postoperative period. This promoted increase of the organism's natural resistance. which had a favourable effect on the course of the postoperative period.

Adjuvants, Immunologic↗