372 research outputs found
Some Effects of Extreme Shortening on Frog Skeletal Muscle
We have established that the sarcolemma of frog skeletal muscle is so firmly tied in at each sarcomere level near the M line, as well as near the Z line, that it is thrown into folds or festoons when the fibers shorten. The attachment is not broken even when the fibers shorten to 25% of optimum tension length. Such extreme shortening affects both the morphology and physiology of the muscle; the morphological change seems to be limited to the myofilaments. The physiological effects in frog sartorius muscle include an increase in resting oxygen consumption and changes in the relation between fiber length and isometric tension similar to those found in isolated muscle fibers
Synthesis, structural studies, and redox chemistry of bimetallic [Mn(CO)₃] and [Re(CO)₃] complexes
Manganese ([Mn(CO)₃]) and rhenium tricarbonyl ([Re(CO)₃]) complexes represent a workhorse family of compounds with applications in a variety of fields. Here, the coordination, structural, and electrochemical properties of a family of mono- and bimetallic [Mn(CO)₃] and [Re(CO)₃] complexes are explored. In particular, a novel heterobimetallic complex featuring both [Mn(CO)₃] and [Re(CO)₃] units supported by 2,2′-bipyrimidine (bpm) has been synthesized, structurally characterized, and compared to the analogous monomeric and homobimetallic complexes. To enable a comprehensive structural analysis for the series of complexes, we have carried out new single crystal X-ray diffraction studies of seven compounds: Re(CO)₃Cl(bpm), anti-[{Re(CO₃)Cl}₂(bpm)], Mn(CO)₃Br(bpz) (bpz = 2,2′-bipyrazine), Mn(CO)₃Br(bpm), syn- and anti-[{Mn(CO3)Br}₂(bpm)], and syn-[Mn(CO₃)Br(bpm)Re(CO)₃Br]. Electrochemical studies reveal that the bimetallic complexes are reduced at much more positive potentials (ΔE ≥ 380 mV) compared to their monometallic analogues. This redox behavior is consistent with introduction of the second tricarbonyl unit which inductively withdraws electron density from the bridging, redox-active bpm ligand, resulting in more positive reduction potentials. [Re(CO₃)Cl]₂(bpm) was reduced with cobaltocene; the electron paramagnetic resonance spectrum of the product exhibits an isotropic signal (near g = 2) characteristic of a ligand-centered bpm radical. Our findings highlight the facile synthesis as well as the structural characteristics and unique electrochemical behavior of this family of complexes
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Characterization of subsurface media from locations up- and down-gradient of a uranium-contaminated aquifer.
The processing of sediment to accurately characterize the spatially-resolved depth profiles of geophysical and geochemical properties along with signatures of microbial density and activity remains a challenge especially in complex contaminated areas. This study processed cores from two sediment boreholes from background and contaminated core sediments and surrounding groundwater. Fresh core sediments were compared by depth to capture the changes in sediment structure, sediment minerals, biomass, and pore water geochemistry in terms of major and trace elements including pollutants, cations, anions, and organic acids. Soil porewater samples were matched to groundwater level, flow rate, and preferential flows and compared to homogenized groundwater-only samples from neighboring monitoring wells. Groundwater analysis of nearby wells only revealed high sulfate and nitrate concentrations while the same analysis using sediment pore water samples with depth was able to suggest areas high in sulfate- and nitrate-reducing bacteria based on their decreased concentration and production of reduced by-products that could not be seen in the groundwater samples. Positive correlations among porewater content, total organic carbon, trace metals and clay minerals revealed a more complicated relationship among contaminant, sediment texture, groundwater table, and biomass. The fluctuating capillary interface had high concentrations of Fe and Mn-oxides combined with trace elements including U, Th, Sr, Ba, Cu, and Co. This suggests the mobility of potentially hazardous elements, sediment structure, and biogeochemical factors are all linked together to impact microbial communities, emphasizing that solid interfaces play an important role in determining the abundance of bacteria in the sediments
Influenza Virus-Specific Immunological Memory Is Enhanced by Repeated Social Defeat
Immunological memory (MEM) development is affected by stress-induced neuroendocrine mediators. Current knowledge about how a behavioral interaction, such as social defeat, alters the development of adaptive immunity, and MEM is incomplete. In this study, the experience of social disruption stress (SDR) prior to a primary influenza viral infection enhanced the frequency and function of the T cell memory pool. Socially stressed mice had a significantly enlarged population of CD8+ T cells specific for the immunodominant NP366–74 epitope of A/PR/8/34 virus in lung and spleen tissues at 6–12 wk after primary infection (resting memory). Moreover, during resting memory, SDR-MEM mice responded with an enhanced footpad delayed-type hypersensitivity response, and more IFN-γ–producing CD4+ T cells were detected after ex vivo stimulation. When mice were rechallenged with A/PR/8/34 virus, SDR-MEM mice terminated viral gene expression significantly earlier than MEM mice and generated a greater DbNP366–74CD8+ T cell response in the lung parenchyma and airways. This enhancement was specific to the T cell response. SDR-MEM mice had significantly attenuated anti-influenza IgG titers during resting memory. Similar experiments in which mice were primed with X-31 influenza and challenged with A/PR/8/34 virus elicited similar enhancements in the splenic and lung airway Db NP366–74CD8+ T cell populations in SDR-MEM mice. This study demonstrates that the experience of repeated social defeat prior to a primary viral infection significantly enhances virus-specific memory via augmentation of memory T cell populations and suggests that social stressors should be carefully considered in the design and analysis of future studies on antiviral immunity
Justice Beyond Borders? Australia and the International Criminal Court
The International Criminal Court (ICC) came into being on 1 July 2002. A four-person team opened an office in The Hague and will collect reports and allegations of genocide, war crimes and crimes against humanity until judges and a prosecutor are appointed towards the end of 2003. Although the court was heralded by many states and international lawyers as the most important positive development in international law since the formation of the United Nations, it did not get off to an auspicious start. The Bush administration was concerned that US military forces operating overseas would be particularly vulnerable to what it described as 'politicised' prosecutions. It therefore insisted that not only would it not be a part of the ICC, but also that it would not sanction the continuation of UN peacekeeping operations. Closer to home, the Australian Senate only ratified the ICC's founding treaty, the Rome Statute, after a bitter debate that split both the Liberal and National parties. This was the case even though the Howard government-and Foreign Minister Alexander Downer in particular-had been a leading advocate of the court and ratification of the Rome Statute had been a Liberal Party election promise in 2001. The cost that Downer, and pro-ICC Attorney-General Daryl Williams had to pay in order to appease restive conservative backbenchers, the National Party, and an increasingly reluctant (and pro-US) Prime Minister and secure the ratification was a declaration that reaffirmed the primacy of the Australian judicial system over the ICC. The declaration insisted that no Australian would be prosecuted by the court without the consent of the Attomey-General, and asserted Australia's right to define what is meant by the crimes of genocide, war crimes, and crimes against humanity. We argue that although Downer and Williams should be commended for their commitment to international justice, the declaration attached to Australia's ratification was unnecessary and unhelpful. The first and third aspects of the declaration were unnecessary: the principle of complementarity enshrined in the Rome Statute means that the ICC already recognises the primacy of domestic jurisdiction, and the crimes covered are already considered to fall under universal jurisdiction, as the Nuremberg, Tokyo and more recent Pinochet trials showed (see Weller 1999). The second is unhelpful because it contravenes both the letter and the spirit of the Rome Statute. We will begin, then, by tracing the development of the ICC debate in Australian politics. In 1998, the government was an enthusiastic advocate of the court but by 2002 an alliance of an ardently pro-US Prime Minister, vocal right-wing parliamentarians and their supporters, and The Australian (and its foreign affairs editor Greg Sheridan in particular) combined to put ratification in doubt. Contrary to Prime Minister John Howard's claims, this debate was not well informed. Instead, it was characterised by hearsay, inaccuracy and scare-mongering. The subsequent section of the article demonstrates this by focusing on the background to, and creation of, the Rome Statute
Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context
Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts
Open‐label, clinical trial extension:Two‐year safety and efficacy results of seladelpar in patients with primary biliary cholangitis
SummaryBackgroundSeladelpar is a potent and selective peroxisome proliferator‐activated receptor‐δ agonist that targets multiple cell types involved in primary biliary cholangitis (PBC), leading to anti‐cholestatic, anti‐inflammatory and anti‐pruritic effects.AimsTo evaluate the long‐term safety and efficacy of seladelpar in patients with PBC.MethodsIn an open‐label, international, long‐term extension study, patients with PBC completing seladelpar lead‐in studies continued treatment. Seladelpar was taken orally once daily at doses of 5 or 10 mg with dose adjustment permitted for safety or tolerability. The primary analysis was for safety and the secondary efficacy analysis examined biochemical markers of cholestasis and liver injury. The study was terminated early due to the unexpected histological findings in a concurrent study for non‐alcoholic steatohepatitis, which were subsequently found to predate treatment. Safety and efficacy data were analysed through 2 years.ResultsThere were no serious treatment‐related adverse events observed among 106 patients treated with seladelpar for up to 2 years. There were four discontinuations for safety, one possibly related to seladelpar. Among 53 patients who completed 2 years of seladelpar, response rates increased from years 1 to 2 for the composite endpoint (alkaline phosphatase [ALP] <1.67 × ULN, ≥15% decrease in ALP, and total bilirubin ≤ULN) and ALP normalisation from 66% to 79% and from 26% to 42%, respectively. In those with elevated bilirubin at baseline, 43% achieved normalisation at year 2.ConclusionsSeladelpar was safe, and markedly improved biochemical markers of cholestasis and liver injury in patients with PBC. These effects were maintained or improved throughout the second year. Clinicaltrials.gov: NCT03301506; Clinicaltrialsregister.eu: 2017‐003910‐16.</jats:sec
Open-label, clinical trial extension: Two-year safety and efficacy results of seladelpar in patients with primary biliary cholangitis
BACKGROUND: Seladelpar is a potent and selective peroxisome proliferator-activated receptor-δ agonist that targets multiple cell types involved in primary biliary cholangitis (PBC), leading to anti-cholestatic, anti-inflammatory and anti-pruritic effects.
AIMS: To evaluate the long-term safety and efficacy of seladelpar in patients with PBC.
METHODS: In an open-label, international, long-term extension study, patients with PBC completing seladelpar lead-in studies continued treatment. Seladelpar was taken orally once daily at doses of 5 or 10 mg with dose adjustment permitted for safety or tolerability. The primary analysis was for safety and the secondary efficacy analysis examined biochemical markers of cholestasis and liver injury. The study was terminated early due to the unexpected histological findings in a concurrent study for non-alcoholic steatohepatitis, which were subsequently found to predate treatment. Safety and efficacy data were analysed through 2 years.
RESULTS: There were no serious treatment-related adverse events observed among 106 patients treated with seladelpar for up to 2 years. There were four discontinuations for safety, one possibly related to seladelpar. Among 53 patients who completed 2 years of seladelpar, response rates increased from years 1 to 2 for the composite endpoint (alkaline phosphatase [ALP] <1.67 × ULN, ≥15% decrease in ALP, and total bilirubin ≤ULN) and ALP normalisation from 66% to 79% and from 26% to 42%, respectively. In those with elevated bilirubin at baseline, 43% achieved normalisation at year 2.
CONCLUSIONS: Seladelpar was safe, and markedly improved biochemical markers of cholestasis and liver injury in patients with PBC. These effects were maintained or improved throughout the second year
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