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Moderate Rates (moderate + rate)
Selected AbstractsGenetic instabilities of (CCTG)·(CAGG) and (ATTCT)·(AGAAT) disease-associated repeats reveal multiple pathways for repeat deletionMOLECULAR CARCINOGENESIS, Issue 4 2009Sharon F. Edwards Abstract The DNA repeats (CTG)·(CAG), (CGG)·(CCG), (GAA)·(TTC), (ATTCT)·(AGAAT), and (CCTG)·(CAGG), undergo expansion in humans leading to neurodegenerative disease. A genetic assay for repeat instability has revealed that the activities of RecA and RecB during replication restart are involved in a high rate of deletion of (CTG)·(CAG) repeats in E. coli. This assay has been applied to (CCTG)·(CAGG) repeats associated with myotonic dystrophy type 2 (DM2) that expand to 11,000 copies and to spinocerebellar ataxia type 10 (SCA10) (ATTCT)·(AGAAT) repeats that expand to 4500 copies in affected individuals. DM2 (CCTG)·(CAGG) repeats show a moderate rate of instability, less than that observed for the myotonic dystrophy type 1 (CTG)·(CAG) repeats, while the SCA10 (ATTCT)·(AGAAT) repeats were remarkably stable in E. coli. In contrast to (CTG)·(CAG) repeats, deletions of the DM2 and SCA10 repeats were not dependent on RecA and RecB, suggesting that replication restart may not be a predominant mechanism by which these repeats undergo deletion. These results suggest that different molecular mechanisms, or pathways, are responsible for the instability of different disease-associated DNA repeats in E. coli. These pathways involve simple replication slippage and various sister strand exchange events leading to deletions or expansions, often associated with plasmid dimerization. The differences in the mechanisms of repeat deletion may result from the differential propensity of these repeats to form various DNA secondary structures and their differential proclivity for primer,template misalignment during replication. © 2009 Wiley-Liss, Inc. [source] Anticoagulation with the direct thrombin inhibitor argatroban in patients presenting with acute coronary syndromes,CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 2 2009Robert W. Yeh MD Abstract Objectives: This study examined the efficacy and safety of the direct thrombin inhibitor argatroban in patients presenting with acute coronary syndromes undergoing cardiac catheterization. Background: Argatroban is a direct-thrombin inhibitor approved for use in percutaneous coronary intervention in patients with heparin-induced thrombocytopenia. Few studies have examined its use in patients undergoing cardiac catheterization for acute coronary syndromes. We performed a retrospective cohort study of patients presenting with acute coronary syndromes who received argatroban anticoagulation during cardiac catheterization. Methods: Consecutive patients presenting with acute coronary syndromes who received argatroban while undergoing cardiac catheterization from 2002 to 2005 were included. Patient characteristics and in-hospital outcomes were examined retrospectively via detailed chart review. The primary endpoints of the study were combined death, myocardial infarction or urgent revascularization, and major bleeding during the index hospitalization. Results: A total of 144 patients presenting with an acute coronary syndrome received argatroban during cardiac catheterization within the study period: 25% presented with ST-elevation myocardial infarction and 75% presented with non-ST-elevation acute coronary syndrome. The combined endpoint of death, myocardial infarction or urgent revascularization occurred in 13.2% of patients during the hospitalization. Major bleeding occurred in 2.1% of patients. Conclusions: In this cohort of patients presenting with acute coronary syndromes, patients receiving argatroban during cardiac catheterization had a moderate rate of adverse cardiac events and a very low rate of major bleeding. © 2009 Wiley-Liss, Inc. [source] Regional-scale measurements of CH4 exchange from a tall tower over a mixed temperate/boreal lowland and wetland forestGLOBAL CHANGE BIOLOGY, Issue 9 2003Cindy Werner The biosphere,atmosphere exchange of methane (CH4) was estimated for a temperate/boreal lowland and wetland forest ecosystem in northern Wisconsin for 1997,1999 using the modified Bowen ratio (MBR) method. Gradients of CH4 and CO2 and CO2 flux were measured on the 447-m WLEF-TV tower as part of the Chequamegon Ecosystem,Atmosphere Study (ChEAS). No systematic diurnal variability was observed in regional CH4 fluxes measured using the MBR method. In all 3 years, regional CH4 emissions reached maximum values during June,August (24±14.4 mg m,2 day,1), coinciding with periods of maximum soil temperatures. In 1997 and 1998, the onset in CH4 emission was coincident with increases in ground temperatures following the melting of the snow cover. The onset of emission in 1999 lagged 100 days behind the 1997 and 1998 onsets, and was likely related to postdrought recovery of the regional water table to typical levels. The net regional emissions were 3.0, 3.1, and 2.1 g CH4 m,2 for 1997, 1998, and 1999, respectively. Annual emissions for wetland regions within the source area (28% of the land area) were 13.2, 13.8, and 10.3 g CH4 m,2 assuming moderate rates of oxidation of CH4 in upland regions in 1997, 1998, and 1999, respectively. Scaling these measurements to the Chequamegon Ecosystem (CNNF) and comparing with average wetland emissions between 40°N and 50°N suggests that wetlands in the CNNF emit approximately 40% less than average wetlands at this latitude. Differences in mean monthly air temperatures did not affect the magnitude of CH4 emissions; however, reduced precipitation and water table levels suppressed CH4 emission during 1999, suggesting that long-term climatic changes that reduce the water table will likely transform this landscape to a reduced source or possibly a sink for atmospheric CH4. [source] Snow metamorphism as revealed by scanning electron microscopyMICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2003Florent Dominé Abstract Current theories of snow metamorphism indicate that sublimating snow crystals have rounded shapes, while growing crystals have shapes that depend on growth rates. At slow growth rates, crystals are rounded. At moderate rates, they have flat faces with rounded edges. At fast growth rates, crystals have flat faces with sharp edges, and they have hollow faces at very fast growth rates. The main growth/sublimation mechanism is thought to be by the homogeneous nucleation of new layers at or near crystal edges. It was also suggested that the equilibrium shape of snow crystals would be temperature dependent: rounded above ,10.5°C, and faceted below. To test these paradigms, we have performed SEM investigations of snow samples having undergone metamorphism under natural conditions, and of snow samples subjected to isothermal metamorphism at ,4° and ,15°C in the laboratory. In general, current theories predicting crystal shapes as a function of growth rates, and of whether crystals are growing or sublimating, are verified. However, the transition in equilibrium shapes from rounded to faceted at ,10.5°C is not observed in our isothermal experiments that reveal a predominance of rounded shapes after more than a month of metamorphism at ,4 and ,15°C. Some small crystals with flat faces that also have sharp angles at ,15°C, are observed in our isothermal experiments. These faces are newly formed, and contradict current theory. Several hypotheses are proposed to explain their occurrence. One is that they are due to sublimation at emerging dislocations. Microsc. Res. Tech. 62:33,48, 2003. © 2003 Wiley-Liss, Inc. [source] Review: Correlations between oxygen affinity and sequence classifications of plant hemoglobins,BIOPOLYMERS, Issue 12 2009Benoit J. Smagghe Abstract Plants express three phylogenetic classes of hemoglobins (Hb) based on sequence analyses. Class 1 and 2 Hbs are full-length globins with the classical eight helix Mb-like fold, whereas Class 3 plant Hbs resemble the truncated globins found in bacteria. With the exception of the specialized leghemoglobins, the physiological functions of these plant hemoglobins remain unknown. We have reviewed and, in some cases, measured new oxygen binding properties of a large number of Class 1 and 2 plant nonsymbiotic Hbs and leghemoglobins. We found that sequence classification correlates with distinct extents of hexacoordination with the distal histidine and markedly different overall oxygen affinities and association and dissociation rate constants. These results suggest strong selective pressure for the evolution of distinct physiological functions. The leghemoglobins evolved from the Class 2 globins and show no hexacoordination, very high rates of O2 binding (,250 ,M,1 s,1), moderately high rates of O2 dissociation (,5,15 s,1), and high oxygen affinity (Kd or P50 , 50 nM). These properties both facilitate O2 diffusion to respiring N2 fixing bacteria and reduce O2 tension in the root nodules of legumes. The Class 1 plant Hbs show weak hexacoordination (KHisE7 , 2), moderate rates of O2 binding (,25 ,M,1 s,1), very small rates of O2 dissociation (,0.16 s,1), and remarkably high O2 affinities (P50 , 2 nM), suggesting a function involving O2 and nitric oxide (NO) scavenging. The Class 2 Hbs exhibit strong hexacoordination (KHisE7 , 100), low rates of O2 binding (,1 ,M,1 s,1), moderately low O2 dissociation rate constants (,1 s,1), and moderate, Mb-like O2 affinities (P50 , 340 nM), perhaps suggesting a sensing role for sustained low, micromolar levels of oxygen. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 1083,1096, 2009. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] | ||||||||||