Eliminating the effects of motion during radiofrequency lesion delivery using a novel contact-force controller.

INTRODUCTION: Catheter-tissue contact force is a determinant of radiofrequency (RF) ablation lesion effectiveness. However, ablation on a beating heart is subject to force variability, making it difficult to optimally deliver consistently durable and transmural lesions. This work evaluates improvements in contact force stability and lesion reproducibility by using a catheter contact-force controller (CFC) during lesion delivery in vitro and in vivo. METHODS AND RESULTS: Using a sheath and force-sensing catheter, an experienced operator attempted to maintain a constant force of 20 g at targets within the atria and left ventricle of a pig manually and using the CFC; the average force and contact-force variation (CFV) achieved using each approach were compared. Ablation lesions (20 W, 30 seconds, 17 mL/min irrigation) were created in bovine tissue samples mounted on a platform programmed to reproduce clinically relevant motion. CFC-assisted lesions were delivered to stationary and moving tissue with forces of 5 to 35  g. Mimicking manual intervention, lesions were also delivered to moving tissue while the CFC was disabled. Resultant lesion volumes were compared using two-way analysis of variance. When using the CFC, the average force was within 1 g of the set level, with a CFV less than 5 g, during both in vitro and in vivo experiments. Reproducible and statistically identical (P = .82) lesion volumes proportional to the set force were achieved in both stationary and moving tissue when the CFC was used. CONCLUSIONS: CFC assistance maintains constant force in vivo and removes effect of motion on lesion volume during RF lesion delivery

A unified dataset of colocated sewage pollution, periphyton, and benthic macroinvertebrate community and food web structure from Lake Baikal (Siberia)

Sewage released from lakeside development can introduce nutrients and micropollutants that can restructure aquatic ecosystems. Lake Baikal, the world’s most ancient, biodiverse, and voluminous freshwater lake, has been experiencing localized sewage pollution from lakeside settlements. Nearby increasing filamentous algal abundance suggests benthic communities are responding to localized pollution. We surveyed 40-km of Lake Baikal’s southwestern shoreline from 19 to 23 August 2015 for sewage indicators, including pharmaceuticals, personal care products, and microplastics, with colocated periphyton, macroinvertebrate, stable isotope, and fatty acid samplings. The data are structured in a tidy format (a tabular arrangement familiar to limnologists) to encourage reuse. Unique identifiers corresponding to sampling locations are retained throughout all data files to facilitate interoperability among the dataset’s 150+ variables. For Lake Baikal studies, these data can support continued monitoring and research efforts. For global studies of lakes, these data can help characterize sewage prevalence and ecological consequences of anthropogenic disturbance across spatial scales

Effects of spatially heterogeneous lakeside development on nearshore biotic communities in a large, deep, oligotrophic lake

Sewage released from lakeside development can reshape ecological communities. Nearshore periphyton can rapidly assimilate sewage-associated nutrients, leading to increases of filamentous algal abundance, thus altering both food abundance and quality for grazers. In Lake Baikal, a large, ultra-oligotrophic, remote lake in Siberia, filamentous algal abundance has increased near lakeside developments, and localized sewage input is the suspected cause. These shifts are of particular interest in Lake Baikal, where endemic littoral biodiversity is high, lakeside settlements are mostly small, tourism is relatively high (~1.2 million visitors annually), and settlements are separated by large tracts of undisturbed shoreline, enabling investigation of heterogeneity and gradients of disturbance. We surveyed sites along 40 km of Baikal’s southwestern shore for sewage indicators—pharmaceuticals and personal care products (PPCPs) and microplastics—as well as periphyton and macroinvertebrate abundance and indicators of food web structure (stable isotopes and fatty acids). Summed PPCP concentrations were spatially related to lakeside development. As predicted, lakeside development was associated with more filamentous algae and lower abundance of sewagesensitive mollusks. Periphyton and macroinvertebrate stable isotopes and essential fatty acids suggested that food web structure otherwise remained similar across sites; yet, the invariance of amphipod fatty acid composition, relative to periphyton, suggested that grazers adjust behavior or metabolism to compensate for different periphyton assemblages. Our results demonstrate that even low levels of human disturbance can result in spatial heterogeneity of nearshore ecological responses, with potential for changing trophic interactions that propagate through the food web

A unified dataset of colocated sewage pollution, periphyton, and benthic macroinvertebrate community and food web structure from Lake Baikal (Siberia)

Sewage released from lakeside development can introduce nutrients and micropollutants that can restructure aquatic ecosystems. Lake Baikal, the world’s most ancient, biodiverse, and voluminous freshwater lake, has been experiencing localized sewage pollution from lakeside settlements. Nearby increasing filamentous algal abundance suggests benthic communities are responding to localized pollution. We surveyed 40-km of Lake Baikal’s southwestern shoreline from 19 to 23 August 2015 for sewage indicators, including pharmaceuticals, personal care products, and microplastics, with colocated periphyton, macroinvertebrate, stable isotope, and fatty acid samplings. The data are structured in a tidy format (a tabular arrangement familiar to limnologists) to encourage reuse. Unique identifiers corresponding to sampling locations are retained throughout all data files to facilitate interoperability among the dataset’s 150+ variables. For Lake Baikal studies, these data can support continued monitoring and research efforts. For global studies of lakes, these data can help characterize sewage prevalence and ecological consequences of anthropogenic disturbance across spatial scales

Global data set of long-term summertime vertical temperature profiles in 153 lakes

Climate change and other anthropogenic stressors have led to long-term changes in the thermal structure, including surface temperatures, deepwater temperatures, and vertical thermal gradients, in many lakes around the world. Though many studies highlight warming of surface water temperatures in lakes worldwide, less is known about long-term trends in full vertical thermal structure and deepwater temperatures, which have been changing less consistently in both direction and magnitude. Here, we present a globally-expansive data set of summertime in-situ vertical temperature profiles from 153 lakes, with one time series beginning as early as 1894. We also compiled lake geographic, morphometric, and water quality variables that can influence vertical thermal structure through a variety of potential mechanisms in these lakes. These long-term time series of vertical temperature profiles and corresponding lake characteristics serve as valuable data to help understand changes and drivers of lake thermal structure in a time of rapid global and ecological change

Global data set of long-term summertime vertical temperature profiles in 153 lakes

Measurement(s) : temperature of water, temperature profile Technology Type(s) : digital curation Factor Type(s) : lake location, temporal interval Sample Characteristic - Environment : lake, reservoir Sample Characteristic - Location : global Machine-accessible metadata file describing the reported data: https://doi.org/10.6084/m9.figshare.14619009Climate change and other anthropogenic stressors have led to long-term changes in the thermal structure, including surface temperatures, deepwater temperatures, and vertical thermal gradients, in many lakes around the world. Though many studies highlight warming of surface water temperatures in lakes worldwide, less is known about long-term trends in full vertical thermal structure and deepwater temperatures, which have been changing less consistently in both direction and magnitude. Here, we present a globally-expansive data set of summertime in-situ vertical temperature profiles from 153 lakes, with one time series beginning as early as 1894. We also compiled lake geographic, morphometric, and water quality variables that can influence vertical thermal structure through a variety of potential mechanisms in these lakes. These long-term time series of vertical temperature profiles and corresponding lake characteristics serve as valuable data to help understand changes and drivers of lake thermal structure in a time of rapid global and ecological change

Characterization of a \u3ci\u3eKCNQ1/KVLQT1\u3c/i\u3e polymorphism in Asian families with LQT2: implications for genetic testing

Congenital long QT syndrome (LQTS) is a genetic disease that predisposes affected individuals to arrhythmias, syncope, and sudden death. Mutations in several ion channel genes have been discovered in different families with LQTS: KCNQ1 (KVLQT1, LQT1), KCNH2 (HERG, LQT2), SCN5A (LQT3), KCNE1 (minK, LQT5), and KCNE2 (MiRP1, LQT6). Previously, the P448R-KVLQT1 missense mutation has been reported as an LQT1-causing mutation. In this report, we demonstrate the presence of the P448R polymorphism in two, unrelated Chinese LQTS families. Although absent from 500 reference alleles derived from 150 white and 100 African-American subjects, P448R was present in 14% of healthy Chinese volunteers. Given the inconsistencies between the genotype (LQT1) and clinical phenotype (LQT2) in our two LQTS families, together with the finding that the P448R appears to be a common, ethnic-specific polymorphism, mutational analysis was extended to the other LQTS-causing genes resulting in the identification of distinct HERG missense mutations in each of these two families. Heterologous expression of P448R-KVLQT1 yielded normal, wild-type (WT) currents. In contrast, the two unique HERG mutations resulted in dominant-negative suppression of the WT HERG channel. Our study has profound implications for those engaged in genetic research. Importantly, one child of the original proband was initially diagnosed with LQT1 based upon the presence of P448R-KVLQT1 and was treated with beta-blockers. However, he did not possess the subsequently determined LQT2-causing mutation. On the other hand, his untreated P448R-negative brother harbored the true, disease-causing HERG mutation. These findings underscore the importance of distinguishing channel polymorphisms from mutations pathogenic for LQTS and emphasize the importance of using appropriate ethnically matched controls in the genotypic analysis of LQTS

Intersexual differences of heat shock response between two amphipods (Eulimnogammarus verrucosus and Eulimnogammarus cyaneus) in Lake Baikal

Acute temperature fluctuations are common in surface waters, and aquatic organisms may manifest physiological responses to punctuated temperature spikes long before behavioral responses. Ectotherms, especially cryophilic stenotherms such as those endemic to Lake Baikal (Siberia), may demonstrate specialized physiological responses to acute temperature increases because their proteomes have evolved to function most efficiently at lower temperatures (e.g., <10 °C). Therefore, our study questioned the nature and degree of variation in physiological response to acute thermal stress in two congenerous, endemic Baikal amphipod species, Eulimnogammarus verrucosus and Eulimnogammarus cyaneus. We hypothesized that because interspecific and intersexual thermosensitivity varies significantly among ectotherms, there would be divergent intersexual and interspecific strategies to withstand acute thermal stress, manifested in different protein compositions and concentrations. We exposed individuals to the species’ respective LT50 for one hour followed by a three-hour recovery period. We then performed 1D-PAGE, Western blotting, 2D-PAGE, and Mass Spectrometry techniques and assessed relative intersexual and interspecific changes in proteomic composition and heat shock protein 70 level. Our results demonstrate that females tend to be more sensitive to an acute thermal stimulus than males, most likely because females allocate significant energy to reproduction and less to heat shock response, evidenced by females’ significantly lower LT50time. Lower level of Hsp70 was found in females of the thermosensitive E. verrucosus compared to males of this species. No intersexual differences were found in Hsp70 level in thermotolerant E. cyaneus. Higher levels of hemocyanin subunits and arginine kinase were found in E. cyaneus females after heat shock and recovery compared to males, which was not found for E. verrucosus, suggesting interspecific mechanisms for E. cyaneus’s higher thermotolerance. These differing responses between species and sexes of Baikal amphipods may reflect more general strategies for maintaining homeostatic conditions during acute thermal stress. As mean surface water temperatures increase worldwide, the net efficiency and efficacy of these strategies could give rise to long term changes in physiology, behavior, and interactions with other species, potentially precipitating population and community level alterations

Indication of ongoing amphipod speciation in Lake Baikal by genetic structures within endemic species

Abstract Background The ancient Lake Baikal is characterized by an outstanding diversity of endemic faunas with more than 350 amphipod species and subspecies. We determined the genetic diversity within the endemic littoral amphipod species Eulimnogammarus verrucosus, E. cyaneus and E. vittatus and investigated whether within those species genetically separate populations occur across Lake Baikal. Gammarus lacustris from water bodies in the Baikal area was examined for comparison. Results Genetic diversities within a species were determined based on fragments of cytochrome c oxidase I (COI) and for E. verrucosus additionally of 18S rDNA. Highly location-specific haplogroups of E. verrucosus and E. vittatus were found at the southern and western shores of Baikal that are separated by the Angara River outflow; E. verrucosus from the eastern shore formed a further, clearly distinct haplotype cluster possibly confined by the Selenga River and Angarskiy Sor deltas. The genetic diversities within these haplogroups were lower than between the different haplogroups. Intraspecific genetic diversities within E. verrucosus and E. vittatus with 13 and 10%, respectively, were similar to interspecies differences indicating the occurrence of cryptic, morphologically highly similar species; for E. verrucosus this was confirmed with 18S rDNA. The haplotypes of E. cyaneus and G. lacustris specimens were with intraspecific genetic distances of 3 and 2%, respectively, more homogeneous indicating no or only recent disruption of gene flow of E. cyaneus across Baikal and recent colonization of water bodies around Baikal by G. lacustris. Conclusions Our finding of separation of subgroups of Baikal endemic amphipods to different degrees points to a species-specific ability of dispersal across areas with adverse conditions and to potential geographical dispersal barriers in Lake Baikal