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Suggested Mechanism (suggested + mechanism)
Selected AbstractsUrsodeoxycholic acid: Mechanism of action and novel clinical applicationsHEPATOLOGY RESEARCH, Issue 2 2008Tadashi Ikegami Ursodeoxycholic acid (UDCA) is used in the treatment of cholestatic liver diseases, gallstone dissolution, and for patients with hepatitis C virus infection to ameliorate elevated alanine aminotransferase levels. The efficacy of UDCA treatment has been debated and the mechanisms of action in humans have still not defined. Suggested mechanisms include the improvement of bile acid transport and/or detoxification, cytoprotection, and anti-apoptotic effects. In this review, we summarize the proposed molecular mechanisms for the action of UDCA, especially in hepatocytes, and also discuss the putative future clinical usage of this unique drug. [source] Quasi-periodic bora gusts related to the structure of the troposphereTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 598 2004Danijel Belu Abstract This study provides a new insight into the behaviour of the bora wind gusts. Wind speed and direction measured with a 1 s sampling interval between 1 December 2001 and 31 January 2002 at Senj (east Adriatic) provided a sufficiently large database for a study of the gusts behaviour. The performed spectral analysis confirmed the occurrence of pulsations in the bora flow. Moreover, a new type of dynamics, involving the onset, cessation and reappearance of the pulsations within a single episode, has been observed in several cases. Suggested mechanisms responsible for generating these phenomena have been determined from comparisons of surface wind data with the upstream tropospheric thermodynamical structure derived from Zagreb radiosonde data. In particular, it has been shown that the appearance of an upper-tropospheric jet stream results in cessation of the pulsations, and the decrease in the jet stream supports quasi-periodic gust behaviour. As the pulsations are generated by wave breaking, the jet stream appearance has been related to the disappearance of the wave-breaking region in the lee of the mountain, which is in accordance with previous studies of downslope windstorms. Copyright © 2004 Royal Meteorological Society. [source] Voltammetric Determination of Phenylglyoxylic Acid in Urine Using Graphite Composite ElectrodeELECTROANALYSIS, Issue 2 2006Navrátil Abstract A composite electrode prepared from graphite powder and epoxy resin was applied as a working electrode for the determination of phenylglyoxylic acid (one of the metabolites of styrene) in human urine. Cathodic differential pulse stripping voltammetry was used and optimum conditions have been found giving the limit of determination about 5,mg L,1. All results were compared with those obtained using hanging mercury drop electrode. For the confirmation of suggested mechanism of the electrochemical reaction the elimination voltammetry with linear scan was used. [source] Spectroscopic Properties of Various Quinolone Antibiotics in Aqueous,organic Solvent Mixtures¶PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2004Hyoung-Ryun Park The spectroscopic properties of enoxacin (ENO), oxolinic acid (OXO) and nalidixic acid (NAL) were studied in various H2O-CH3OH and H2O-CH3CN mixed solvents because these solvents were thought to behave as a biological mimetic system. ENO has piperazinyl group, but OXO and NAL do not have this substituent. The fluorescence emission spectra of ENO were very sensitive to the composition of the solvents. In the Lippert-Mataga analysis of the steady-state fluorescence data, clear reverse solvatochromism was exhibited for ENO in both mixed solvents. This observation can be explained using the excited state twisted intramolecular charge transfer (TICT) from the nitrogen of the piperazinyl group to the keto oxygen. Theoretical calculations further support this observation. The nonradiative and radiative rate constants of these molecules were analyzed as a function of dipolarity,polarizability (,*) and hydrogen bond donor acidity (,) of the mixed solvents. These results for ENO were consistent with the suggested mechanism of the TICT very well. The influence of bulk dielectric effect was more significant relative to the specific hydrogen bonding interactions. The emission spectra of OXO and NAL do not exhibit any characteristic responses to the properties of the solvent. [source] Influence of Heavy Cigarette Smoking on Heart Rate Variability and Heart Rate Turbulence ParametersANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 4 2009Goksel Cagirci M.D. Background: Cigarette smoking increases the risk of cardiovascular events related with several mechanisms. The most suggested mechanism is increased activity of sympathetic nervous system. Heart rate variability (HRV) and heart rate turbulence (HRT) has been shown to be independent and powerful predictors of mortality in a specific group of cardiac patients. The goal of this study was to assess the effect of heavy cigarette smoking on cardiac autonomic function using HRV and HRT analyses. Methods: Heavy cigarette smoking was defined as more than 20 cigarettes smoked per day. Heavy cigarette smokers, 69 subjects and nonsmokers 74 subjects (control group) were enrolled in this study. HRV and HRT analyses [turbulence onset (TO) and turbulence slope (TS)] were assessed from 24-hour Holter recordings. Results: The values of TO were significantly higher in heavy cigarette smokers than control group (,1.150 ± 4.007 vs ,2.454 ± 2.796, P = 0.025, respectively), but values of TS were not statistically different between two groups (10.352 ± 7.670 vs 9.613 ± 7.245, P = 0.555, respectively). Also, the number of patients who had abnormal TO was significantly higher in heavy cigarette smokers than control group (23 vs 10, P = 0.006). TO was correlated with the number of cigarettes smoked per day (r = 0.235, P = 0.004). While LF and LF/HF ratio were significantly higher, standard deviation of all NN intervals (SDNN), standard deviation of the 5-minute mean RR intervals (SDANN), root mean square of successive differences (RMSSD), and high-frequency (HF) values were significantly lower in heavy smokers. While, there was significant correlation between TO and SDNN, SDANN, RMSSD, LF, and high frequency (HF), only HF was correlated with TS. Conclusion: Heavy cigarette smoking has negative effect on autonomic function. HRT is an appropriate noninvasive method to evaluate the effect of cigarette on autonomic function. Simultaneous abnormal HRT and HRV values may explain increased cardiovascular event risk in heavy cigarette smokers. [source] Exploring the link between microorganisms and oral cancer: A systematic review of the literatureHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 9 2009Samuel J. Hooper PhD Abstract The majority of cases of oral cancer have been related to tobacco use and heavy alcohol consumption. However, the incidence of oral cavity carcinoma appears to be increasing in many parts of the world in a manner that it is difficult to explain with traditional risk factors alone. Meanwhile, interest in the possible relationships between microorganisms and the different stages of cancer development has been rising and numerous mechanisms by which bacteria and yeast may initiate or promote carcinogenesis are currently under investigation. In particular, a persuasive body of evidence suggests a possible etiological role involving the metabolism and production of carcinogenic products, such as acetaldehyde. Other suggested mechanisms include the induction of chronic inflammation and direct interference with eukaryotic cell cycle and signaling pathways. This review aims to summarize the known associations between microbial infection and cancer and draw attention to how they may relate to oral carcinoma. © 2009 Wiley Periodicals, Inc. Head Neck, 2009 [source] The relationship between potency of oxidative stress and severity of depressionACTA NEUROPSYCHIATRICA, Issue 4 2004Medaim Yanik Background:, Oxidative stress is one of the suggested mechanisms in major depression. Objective:, To determine the oxidative and antioxidative status of plasma of patients with major depression and to investigate whether there is a relationship between the potency of oxidative stress and the severity of depression. Methods:, To determine the antioxidative status of plasma, total and individual antioxidant levels which are total antioxidant potential (TAOP), total protein, albumin, uric acid, vitamin C and total bilirubin were measured. To determine the oxidative status, total peroxide level of plasma was measured in patients with drug-free depressive patients and compared with those of controls. Per cent ratio of total peroxide to TAOP was evaluated as oxidative stress index (OSI). Results:, Plasma TAOP and individual antioxidant levels were found to be lower in patients with depression than those of controls. On the contrary, the patients had high total plasma peroxide levels. OSI values of the patients were significantly higher than those of controls (P = 0.002), and a significant positive correlation between Hamilton Depression Rating Scale (HDRS) and OSI values was found (r = 0.54, P = 0.01). Conclusions:, The patients with major depression are exposed to oxidative stress, and OSI may be useful to reflect the severity of the disease. [source] | ||||||||||