Streptococcus spp are opportunistic pathogens that normally reside in the upper respiratory, intestinal, lower urinary, and genital tracts but can cause localized infection or septicemia in dogs of ...all ages. A retrospective study of streptococcal infection in 393 dogs was conducted to identify the species of Streptococcus isolated, determine demographics of affected dogs, and characterize the disease processes associated with infection. The major streptococcal species isolated were S canis (88 cases, 22.4%), S dysgalactiae ssp equisimilis (13, 3.3%), and S equi ssp zooepidemicus (4, 1.0%). Sex was not a risk factor (P > .30). Fetuses and neonates were more likely to have streptococcal infection than were other age groups (P < .001). Streptococcal septicemia was considered an important cause of abortion and neonatal death and was isolated from all samples submitted for aerobic culture from dogs in that age group. There was a seasonal trend, with dogs more likely to have streptococcal infection in summer months. In dogs for which a disease process was identified, streptococcal infection was associated with dermatitis (29 dogs), pneumonia (24 dogs), adult septicemia (13 dogs), and fetal/neonatal septicemia leading to abortion or neonatal death (16 dogs). Identification of other clinically significant bacterial, viral, fungal, and parasitic organisms was common (267 of 393 dogs, 68%), especially in dogs with dermatitis or pneumonia. Infection with Streptococcus spp should be considered in the differential diagnosis in cases of abortion, septicemia, dermatitis, and pneumonia in dogs. Clinical significance of isolation of streptococcal organisms should be interpreted in context of clinical signs and pathologic findings.
Most fishes known for terrestrial locomotion are small and/or elongate. Northern snakeheads (
) are large, air-breathing piscivores anecdotally known for terrestrial behaviors. Our goals were to ...determine their environmental motivations for emersion, describe their terrestrial kinematics for fish 3.0-70.0 cm and compare kinematics among four substrates. For emersion experiments,
was individually placed into aquatic containers with ramps extending through the surface of the water, and exposed to 15 ecologically-relevant environmental conditions. For kinematic experiments, fish were filmed moving on moist bench liner, grass, artificial turf, and a flat or tilted rubber boat deck. Videos were digitized for analysis in MATLAB and electromyography was used to measure muscular activity. Only the low pH (4.8), high salinity (30 ppt), and high dCO
(10% seltzer solution) treatments elicited emersion responses. While extreme, these conditions do occur in some of their native Asian swamps. Northern snakeheads >4.5 cm used a unique form of axial-appendage-based terrestrial locomotion involving cyclic oscillations of the axial body, paired with near-simultaneous movements of both pectoral fins. Individuals ≤3.5 cm used tail-flip jumps to travel on land. Northern snakeheads also moved more quickly on complex, three-dimensional substrates (e.g., grass) than on smooth substrates (e.g., bench liner), and when moving downslope. Release of snakeheads onto land by humans or accidentally by predators may be more common than voluntary emersion, but because northern snakeheads can respire air, it may be necessary to factor in the ability to spread overland into the management of this invasive species.
The Athel silicilyte is an enigmatic, hundreds of meters thick, finely laminated quartz deposit, in which silica precipitated in deep water (>~100–200 m) at the Ediacaran–Cambrian boundary in the ...South Oman Salt Basin. In contrast, Meso‐Neoproterozoic sinks for marine silica were dominantly restricted to peritidal settings. The silicilyte is known to contain sterane biomarkers for demosponges, which today are benthic, obligately aerobic organisms. However, the basin has previously been described as permanently sulfidic and time‐equivalent shallow‐water carbonate platform and evaporitic facies lack silica. The Athel silicilyte thus represents a unique and poorly understood depositional system with implications for late Ediacaran marine chemistry and paleoecology. To address these issues, we made petrographic observations, analyzed biomarkers in the solvent‐extractable bitumen, and measured whole‐rock iron speciation and oxygen and silicon isotopes. These data indicate that the silicilyte is a distinct rock type both in its sedimentology and geochemistry and in the original biology present as compared to other facies from the same time period in Oman. The depositional environment of the silicilyte, as compared to the bounding shales, appears to have been more reducing at depth in sediments and possibly bottom waters with a significantly different biological community contributing to the preserved biomarkers. We propose a conceptual model for this system in which deeper, nutrient‐rich waters mixed with surface seawater via episodic mixing, which stimulated primary production. The silica nucleated on this organic matter and then sank to the seafloor, forming the silicilyte in a sediment‐starved system. We propose that the silicilyte may represent a type of environment that existed elsewhere during the Neoproterozoic. These environments may have represented an important locus for silica removal from the oceans.
TNK-tissue plasminogen activator (TNK-TPA) is a genetically engineered variant of TPA, which in experimental models has a slower plasma clearance and greater fibrin specificity and is 80-fold more ...resistant to plasminogen activator inhibitor-1 than alteplase TPA.
The thrombolysis in Myocardial Infarction (TIMI) 10A trial was a Phase 1, dose-ranging pilot trial designed to evaluate the pharmacokinetics, safety, and efficacy of TNK-TPA in patients with acute myocardial infarction. One hundred thirteen patients with acute ST-segment elevation myocardial infarction presenting within 12 hours and without contraindications to thrombolysis were enrolled and treated with a single bolus of TNK-TPA over 5 to 10 seconds with doses ranging from 5 to 50 mg. TNK-TPA demonstrated a plasma clearance of 151 +/- 55 mL/min and a half-life of 17 +/- 7 minutes. Comparable values for wild-type TPA are 572 +/- 132 mL/min and 3.5 +/- 1.4 minutes, respectively. Systemic fibrinogen and plasminogen levels fell by only 3% and 13%, respectively, at 1 hour after TNK-TPA administration. TIMI grade 3 flow at 90 minutes was achieved in 57% to 64% of patients at the 30- to 50-mg doses. Seven patients (6.2%) experienced a major hemorrhage, which occurred at a vascular access site in six patients.
TNK-TPA has a prolonged half-life so it can be administered as a single bolus. TNK-TPA appears to be very fibrin specific, and the initial patency and safety profiles are encouraging. Further study of this new thrombolytic agent is ongoing.
Category learning theorists tacitly assume that stimuli are encoded by a single pathway. Motivated by theories of object recognition, we evaluated a dual-pathway account of stimulus encoding. The ...part-based pathway establishes mappings between sensory input and symbols that encode discrete stimulus features, whereas the image-based pathway applies holistic templates to sensory input. Our experiments used rule-plus-exception structures, in which one exception item in each category violates a salient regularity and must be distinguished from other items. In Experiment 1, we found discrete representations to be crucial for recognition of exceptions following brief training. Experiments 2 and 3 involved multisession training regimens designed to encourage either part- or image-based encoding. We found that both pathways are able to support exception encoding, but have unique characteristics. We speculate that one advantage of the part-based pathway is the ability to generalize across domains, whereas the image-based pathway provides faster and more effortless recognition.
The atmosphere–ocean system experienced a progressive change from anoxic to more oxidizing conditions through time. This oxidation is traditionally envisaged to have occurred as two stepwise ...increases in atmospheric oxygen at the beginning and end of the Proterozoic Eon. Here, we present a study of the redox-sensitive element, uranium, in organic-rich shales to track the history of Earth's surface oxidation at an unprecedented temporal resolution. Fluctuations in the degree of uranium enrichment in organic-rich shales suggest that the initial rise of atmospheric oxygen ~2.4billionyr ago was followed by a decline to less oxidizing conditions during the mid-Proterozoic. This redox state persisted for almost 1billionyr, ending with a second oxygenation event in the latest Neoproterozoic. The U record tracks major fluctuations in surface oxygen level and challenges conventional models that suggest the Earth underwent a unidirectional rise in atmospheric oxygen during the Precambrian.
•The U of seawater has not been constant throughout geologic time.•The U of seawater is linked to changes in oceanic and atmospheric oxygen content.•Secular changes in U demonstrate a drop in O2 after the GOE.
The rapid clearance of t-PA from plasma requires administration by intravenous (I.V.) infusion. A slower clearing, fibrin-specific rt-PA variant may allow single intravenous bolus administration, ...thereby simplifying dosing. This study was designed to characterize the pharmacokinetics of the slower clearing, fibrin-specific tissue-plasminogen activator variant, TNK-tPA, in patients with acute myocardial infarction (AMI) following a single I.V. bolus injection. Single I.V. bolus doses of 5 to 50 mg of TNK-tPA were studied in an open-label, multicenter, dose escalation study. A total of 113 AMI patients were enrolled. Blood sampling for pharmacokinetics was conducted in eighty-two patients (72 men, 10 women), with 5 to 27 patients per dose. TNK-tPA was administered as an I.V. bolus over 5-10 s. Following I.V. bolus administration, there was a biphasic elimination of TNK-tPA from plasma. The initial phase had a mean half-life that ranged from 11 +/- 5 to 20 +/- 6 min and was followed by a terminal phase with a mean half-life that ranged from 41 +/- 16 to 138 +/- 84 min. Mean TNK-tPA plasma clearance was 125 +/- 25 - 216 +/- 98 ml/min, and the initial volume of distribution was 4.3 +/- 2 - 8.4 +/- 6 1. A decrease in TNK-tPA plasma clearance with increasing TNK-tPA dose was noted. In addition, women and patients with lower body weight or older age had a slower plasma clearance. In conclusion, TNK-tPA has a slower plasma clearance in patients with AMI than that reported for rt-PA, allowing administration as a single I.V. bolus.
The small protein ubiquitin (76 amino acids) has been synthesized under optimized conditions by Merrifield solid-phase methodology using the Nalpha-Fmoc protecting group. The crude polypeptide ...mixture was purified to homogeneity by gel filtration, dialysis and a combination of cation- and anion-exchange chromatography to yield ubiquitin. Amino acid analysis, enzymic digestion and sequencing by automated Edman degradation were used to authenticate the primary structure. Isoelectric focusing and m.s. were used to demonstrate that the final product was greater than 98% pure with a final yield of 93 mg (4.3%) from a single synthesis on a 0.25 nmol scale.
Ultrasonic cavitation was employed to enhance sensitivity of bacterial spore immunoassay detection, specifically, enzyme-linked immunosorbent assay (ELISA) and resonant mirror (RM) sensing. Bacillus ...spore suspensions were exposed to high-power ultrasound in a tubular sonicator operated at 267 kHz in both batch and flow modes. The sonicator was designed to deliver high output power and is in a form that can be cooled efficiently to avoid thermal denaturation of antigen. The 30-s batch and cooled flow (0.3 mL/min) sonication achieved an ∼20-fold increase in ELISA sensitivity compared to unsonicated spores by ELISA. RM sensing of sonicated spores achieved detection sensitivity of ∼106 spores/mL, whereas unsonicated spores were undetectable at the highest concentration tested. Improvements in detection were associated with antigen released from the spores. Equilibrium temperature increase in the tubular sonicator was limited to 14 K after 30 min and was maintained for 6 h with cooling and flow (0.3 mL/min). The work described here demonstrates the utility of the tubular sonicator for the improvement in the sensitivity of the detection of spores and its suitability as an in-line component of a rapid detection system.
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