174 research outputs found

    Genome Sequence Analysis of Dengue Virus 1 Isolated in Key West, Florida

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    Dengue virus (DENV) is transmitted to humans through the bite of mosquitoes. In November 2010, a dengue outbreak was reported in Monroe County in southern Florida (FL), including greater than 20 confirmed human cases. The virus collected from the human cases was verified as DENV serotype 1 (DENV-1) and one isolate was provided for sequence analysis. RNA was extracted from the DENV-1 isolate and was used in reverse transcription polymerase chain reaction (RT-PCR) to amplify PCR fragments to sequence. Nucleic acid primers were designed to generate overlapping PCR fragments that covered the entire genome. The DENV-1 isolate found in Key West (KW), FL was sequenced for whole genome characterization. Sequence assembly, Genbank searches, and recombination analyses were performed to verify the identity of the genome sequences and to determine percent similarity to known DENV-1 sequences. We show that the KW DENV-1 strain is 99% identical to Nicaraguan and Mexican DENV-1 strains. Phylogenetic and recombination analyses suggest that the DENV-1 isolated in KW originated from Nicaragua (NI) and the KW strain may circulate in KW. Also, recombination analysis results detected recombination events in the KW strain compared to DENV-1 strains from Puerto Rico. We evaluate the relative growth of KW strain of DENV-1 compared to other dengue viruses to determine whether the underlying genetics of the strain is associated with a replicative advantage, an important consideration since local transmission of DENV may result because domestic tourism can spread DENVs

    Dilated Cardiomyopathy with Increased SR Ca2+ Loading Preceded by a Hypercontractile State and Diastolic Failure in the α1CTG Mouse

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    Mice over-expressing the α1−subunit (pore) of the L-type Ca2+ channel (α1CTG) by 4months (mo) of age exhibit an enlarged heart, hypertrophied myocytes, increased Ca2+ current and Ca2+ transient amplitude, but a normal SR Ca2+ load. With advancing age (8–11 mo), some mice demonstrate advanced hypertrophy but are not in congestive heart failure (NFTG), while others evolve to frank dilated congestive heart failure (FTG). We demonstrate that older NFTG myocytes exhibit a hypercontractile state over a wide range of stimulation frequencies, but maintain a normal SR Ca2+ load compared to age matched non-transgenic (NTG) myocytes. However, at high stimulation rates (2–4 Hz) signs of diastolic contractile failure appear in NFTG cells. The evolution of frank congestive failure in FTG is accompanied by a further increase in heart mass and myocyte size, and phospholamban and ryanodine receptor protein levels and phosphorylation become reduced. In FTG, the SR Ca2+ load increases and Ca2+ release following excitation, increases further. An enhanced NCX function in FTG, as reflected by an accelerated relaxation of the caffeine-induced Ca2+ transient, is insufficient to maintain a normal diastolic Ca2+ during high rates of stimulation. Although a high SR Ca2+ release following excitation is maintained, the hypercontractile state is not maintained at high rates of stimulation, and signs of both systolic and diastolic contractile failure appear. Thus, the dilated cardiomyopathy that evolves in this mouse model exhibits signs of both systolic and diastolic failure, but not a deficient SR Ca2+ loading or release, as occurs in some other cardiomyopathic models

    Intravenous alteplase for stroke with unknown time of onset guided by advanced imaging: systematic review and meta-analysis of individual patient data

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    Background: Patients who have had a stroke with unknown time of onset have been previously excluded from thrombolysis. We aimed to establish whether intravenous alteplase is safe and effective in such patients when salvageable tissue has been identified with imaging biomarkers. Methods: We did a systematic review and meta-analysis of individual patient data for trials published before Sept 21, 2020. Randomised trials of intravenous alteplase versus standard of care or placebo in adults with stroke with unknown time of onset with perfusion-diffusion MRI, perfusion CT, or MRI with diffusion weighted imaging-fluid attenuated inversion recovery (DWI-FLAIR) mismatch were eligible. The primary outcome was favourable functional outcome (score of 0–1 on the modified Rankin Scale [mRS]) at 90 days indicating no disability using an unconditional mixed-effect logistic-regression model fitted to estimate the treatment effect. Secondary outcomes were mRS shift towards a better functional outcome and independent outcome (mRS 0–2) at 90 days. Safety outcomes included death, severe disability or death (mRS score 4–6), and symptomatic intracranial haemorrhage. This study is registered with PROSPERO, CRD42020166903. Findings: Of 249 identified abstracts, four trials met our eligibility criteria for inclusion: WAKE-UP, EXTEND, THAWS, and ECASS-4. The four trials provided individual patient data for 843 individuals, of whom 429 (51%) were assigned to alteplase and 414 (49%) to placebo or standard care. A favourable outcome occurred in 199 (47%) of 420 patients with alteplase and in 160 (39%) of 409 patients among controls (adjusted odds ratio [OR] 1·49 [95% CI 1·10–2·03]; p=0·011), with low heterogeneity across studies (I2=27%). Alteplase was associated with a significant shift towards better functional outcome (adjusted common OR 1·38 [95% CI 1·05–1·80]; p=0·019), and a higher odds of independent outcome (adjusted OR 1·50 [1·06–2·12]; p=0·022). In the alteplase group, 90 (21%) patients were severely disabled or died (mRS score 4–6), compared with 102 (25%) patients in the control group (adjusted OR 0·76 [0·52–1·11]; p=0·15). 27 (6%) patients died in the alteplase group and 14 (3%) patients died among controls (adjusted OR 2·06 [1·03–4·09]; p=0·040). The prevalence of symptomatic intracranial haemorrhage was higher in the alteplase group than among controls (11 [3%] vs two [<1%], adjusted OR 5·58 [1·22–25·50]; p=0·024). Interpretation: In patients who have had a stroke with unknown time of onset with a DWI-FLAIR or perfusion mismatch, intravenous alteplase resulted in better functional outcome at 90 days than placebo or standard care. A net benefit was observed for all functional outcomes despite an increased risk of symptomatic intracranial haemorrhage. Although there were more deaths with alteplase than placebo, there were fewer cases of severe disability or death. Funding: None

    Effect of methionine sulfoximine on methylation of guanine residues in astroglial transfer ribonucleic acids

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    Culture-grown astrocytes derived from 3-day-old rat brain were incubated in the presence of [ 3 H]guanosine and of the convulsant agent l -methionine- dl -sulfoximine (MSO). The resulting [ 3 H]tRNA was purified from control and MSO-exposed cells at several time points during the incubation and was hydrolyzed to [ 3 H]guanine and four [ 3 H]methyl guanines which were separated by high pressure liquid chromatography. Three of the four [ 3 H]methyl guanines were more highly labeled in the [ 3 H]tRNA of the MSO-exposed cells, relative to that of the control cells throughout the entire incubation period. The findings extend to cultured astrocytes, the stimulatory effect of MSO on the methylation of neural tRNA guanines, previouly observed both in vitro using [ 14 C] S -adenosyl- l -methionine and in vivo using [ methyl 3 -H] l -methionine.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45427/1/11064_2004_Article_BF00964832.pd

    Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

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    BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

    Intervalence charge transfer (IVCT) in trinuclear and tetranuclear complexes of iron, ruthenium, and osmium

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    Electron and energy transfer are ubiquitous in biological, chemical, and physical processes, which has led to extensive multidisciplinary research efforts to elucidate the factors influencing mechanistic pathways. Of considerable importance in these studies have been investigations of intramolecular electron and energy transfer within polymetallic assemblies as a result of the diversity (coordination number, ligand environment, stereochemistry, and redox characteristics) provided by the metal centers in such structures.\ud \ud Because of their multicomponent nature, these structures have considerable design potential to exploit the cooperation between the metals and/or other redox-active centers. Novel photochemical molecular devices (PMDs) may be constructed which are capable of performing useful light- and redox-induced functionsincluding artificial photosynthesis and photoinduced energy- and electron-transfer processes in light-harvesting “antenna” systems. Metallosupramolecular assemblies have also been designed to mimic the photoinduced charge separation function in photosynthetic organisms, in an attempt to elucidate the complex electron- and energy-transfer mechanisms which occur in natural systems. The possibility of multiple electron transferby absorption of several photons by linked chromophores, or the design of systems which generate more than one electron upon absorption of one photonhas significant implications in catalytic schemes, as well as understanding long-range electron transfer in biological systems, and the conductivity of “molecular wires”. In molecules involving delocalized unpaired electrons, polarizability may be present so that the species exhibit interesting nonlinear optical or magnetic properties.\ud \ud Polypyridyl complexes of the d^6 metals Fe^II, Ru^II, and OsII have attracted particular attention as the basis of these assemblies due to a combination of favorable photophysical and redox characteristics, the longevity of their excited states, and their chemical inertness in a variety of oxidation states. An important feature of these complexes is the capability of systematic variation of the ground- and excited-state properties by the judicious choice of the coordinating ligands

    Primary Photoinduced Processes in Bimetallic Dyads with Extended Aromatic Bridges. Tetraazatetrapyridopentacene Complexes of Ruthenium(II) and Osmium(II)

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    The photophysics of the binuclear complexes [(phen)2M(tatpp)M(phen)2]4+, where M ) Ru or Os, phen ) 1,10- phenanthroline, and tatpp ) 9,11,20,22-tetraazatetrapyrido[3,2-a:2¢3¢-c:3¢¢,2¢¢-l:2¢¢¢,3¢¢¢]pentacene, has been studied in acetonitrile and dichloromethane by femtosecond and nanosecond time-resolved techniques. The results demonstrate that complexes of different metals have different types of lowest excited state: a tatpp ligand-centered (LC) triplet in the case of Ru(II); a metal-to-ligand charge-transfer (MLCT) triplet state in the case of Os(II). The excited-state kinetics is strongly solvent-dependent. In the Ru(II) system, the formation and decay of the LC state take place, respectively, in 25 ps and ca. 5 ns in CH3CN and in 0.5 ps and 1.3 ís in CH2Cl2. These solvent effects can be rationalized on the basis of a thermally activated decay of the LC state through the upper MLCT state. In the Os(II) system, the formation and decay of the MLCT state take place, respectively, in 3.8 and 60 ps in CH3CN and in 0.5 and 4 ps in CH2Cl2. These effects are consistent with the solvent sensitivity of the MLCT energy, in terms of driving force and energy-gap law arguments. The relevance of these results for the use of ladder-type aromatic bridges as potential molecular wires is discussed
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