460 research outputs found
Variability of Symmetric Dimethylarginine in apparently healthy dogs
Background: Symmetric dimethylarginine (SDMA) is a screening tool for early kidney dysfunction and monitoring treatment in cases of chronic kidney disease (CKD). There are no current studies describing the suitability of this test for use with published populationbased reference intervals.
Hypothesis/Objectives: To determine the components of biological variability, the index of individuality (IOI), the critical difference between sequential measurements (CD) and the number of measurements required to assess the homeostatic set point (HSP), for both SDMA and serum creatinine (sCr), in apparently healthy dogs.
Animals: Twenty apparently healthy adult dogs owned by clients or staff at a veterinary teaching hospital.
Methods: Prospective, observational study. Blood was collected from each dog on 9 occasions, and SDMA and sCr were measured in duplicate using commercially available assays.
Results: SDMA and sCr had intermediate and low IOI values of 0.87 and 0.28, respectively. The CD of SDMA and sCr, was 1.34 mg/dL and 0.89 mmol/L, respectively. The sample numbers required for estimation of an individualâs HSP (with 90 and 95% CI) for SDMA and sCr were 8 and 45, and 2 and 12 sequential measurements, respectively.
Conclusions and Clinical Importance: Based on our findings, in comparison to sCr, SDMA is better suited for use with population based reference intervals. False-negative test results could occur when comparing a single test result from an individual to such intervals. Ideally CD should be used with sequential measurements
The effect of urine concentration and pH on the growth of Escherichia coli in canine urine in vitro
Background:
Lower urinary tract infections are common in dogs, and Escherichia coli is the most common bacterial pathogen isolated. The literature has conflicting evidence regarding the inhibitory effects of urine concentration and pH on E. coli growth.
Hypothesis/Objectives:
To determine the effect of different pH and urine concentrations on E. coli growth in vitro.
Animals:
Voided urine samples from 10 apparently healthy spayed female dogs were used.
Methods:
A matrix of 9 urine specific gravity (USG; 1.010, 1.020, and 1.030) and pH (5.5, 7.0, and 8.5) combinations was prepared by diluting and titrating filtered voided urine samples. Three E. coli isolates were obtained from urine of female dogs with signs of lower urinary tract infection and cultured at different urine pH and USG combinations in wells of a microtiter plate. The number of E. coli colonyâforming units (CFU) per mL of urine was calculated after aerobic incubation of the urine at 37°C for 18 hours, and statistically compared.
Results:
Significant differences were identified in the mean log CFU/mL among different combinations of pH and USG. The lowest log CFU/mL were observed in alkaline concentrated urine (pH 8.5 and USG 1.030).
Conclusions and Clinical Importance:
Escherichia coli in vitro growth was higher in neutral to acidic and diluted urine compared to alkaline and concentrated urine. The impact of nonâalkalizing diluting diets on the incidence of E. coli lower urinary tract infections should be further explored
Geomagnetic storm dependence on the solar flare class
Content. Solar flares are often used as precursors of geomagnetic storms. In
particular, Howard and Tappin (2005) recently published in A&A a dependence
between X-ray class of solar flares and Ap and Dst indexes of geomagnetic
storms which contradicts to early published results.
Aims. We compare published results on flare-storm dependences and discuss
possible sources of the discrepancy.
Methods. We analyze following sources of difference: (1) different intervals
of observations, (2) different statistics and (3) different methods of event
identification and comparison.
Results. Our analysis shows that magnitude of geomagnetic storms is likely to
be independent on X-ray class of solar flares.Comment: 3 pages, 1 tabl
Kinetics of plasma cellâfree DNA and creatine kinase in a canine model of tissue injury
Background:
Cellâfree DNA (cfDNA) comprises short, doubleâstranded circulating DNA sequences released from damaged cells. In people, cfDNA concentrations correlate well with disease severity and tissue damage. No reports are available regarding cfDNA kinetics in dogs.
Objectives/Hypothesis:
Cellâfree DNA will have a short biological halfâlife and would be able to stratify mild, moderate, and severe tissue injury. Our study aims were to determine the kinetics and biological halfâlife of cfDNA and to contrast them with those of creatine kinase (CK).
Animals:
Three groups of 10 dogs undergoing open ovariohysterectomy, surgery for cranial cruciate ligament rupture (CCLR), or hemilaminectomy.
Methods:
Plasma for cfDNA and CK analysis was collected at admission, at induction of anesthesia, postsurgery (time 0) and at 6, 12, 24, 36, 48, 60, and 72 hours after surgery.
Results:
The biological halfâlife of plasma cfDNA and CK were 5.64 hours (95% confidence interval [CI 95], 4.36â7.98 hours) and 28.7 hours (CI95, 25.3â33.3 hours), respectively. In the hemilaminectomy group, cfDNA concentrations differed significantly from admission at 6â12 hours after surgery. Creatine kinase activity differed among the surgical groups and reached a peak 6 hours after surgery. In the ovariohysterectomy and CCLR groups, plasma CK activity 72 hours after surgery did not differ from admission activity of the ovariohysterectomy group. In contrast, in the hemilaminectomy group, plasma CK activity after 72 hours did not return to the ovariohysterectomy group admission activity.
Conclusions and Clinical Importance:
Plasma CK activity has a longer biological halfâlife than previously thought. In contrast to plasma CK activity, cfDNA has a short halfâlife and could be a useful marker for peracute severe tissue injury
Effects of Diabetes and Insulin on α-amylase Messenger RNA Levels in Rat Parotid Glands
Previous studies have shown that amylase levels are reduced significantly in the pancreas and parotid gland of diabetic rats and that insulin reverses this effect and increases the secretory protein levels. In the pancreas, these changes in amylase protein levels are accompanied by parallel changes in amylase mRNA levels. In the present study, the effects of diabetes and subsequent insulin treatments on contents (per cell) of amylase protein and its mRNA in parotid glands were compared in rats rendered diabetic with an injection of a beta-cell toxin, streptozotocin (STZ). Both amylase protein and its mRNA contents were reduced significantly in diabetic rats, compared with control rats, and this reduction was reversed following insulin injections of diabetic rats. In insulin-injected diabetic rats, amylase protein contents increased before a detectable increase in amylase mRNA levels was seen. The mRNA contents of a non-secretory protein, actin, did not change during diabetogenesis or subsequent insulin treatments. The reductions in parotid contents of amylase and its mRNA in diabetic rats and the reversal of these changes by insulin are similar to those changes that occur in the pancreas under the same conditions. However, the magnitude of these changes in parotid glands was much smaller than in the pancreas, and the effect of insulin on amylase mRNA synthesis was not as immediate as in the latter gland.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67977/2/10.1177_00220345900690081001.pd
The Energetics of Li Off-Centering in KLiTaO; First Principles Calculations
KLiTaO (KLT) solid solutions exhibit a variety of
interesting physical phenomena related to large displacements of Li-ions from
ideal perovskite A-site positions. First-principles calculations for KLT
supercells were used to investigate these phenomena. Lattice dynamics
calculations for KLT exhibit a Li off-centering instability. The energetics of
Li-displacements for isolated Li-ions and for Li-Li pairs up to 4th neighbors
were calculated. Interactions between nearest neighbor Li-ions, in a Li-Li
pair, strongly favor ferroelectric alignment along the pair axis. Such Li-Li
pairs can be considered "seeds" for polar nanoclusters in KLT.
Electrostriction, local oxygen relaxation, coupling to the KT soft-mode, and
interactions with neighboring Li-ions all enhance the polarization from Li
off-centering. Calculated hopping barriers for isolated Li-ions and for nearest
neighbor Li-Li pairs are in good agreement with Arrhenius fits to experimental
dielectric data.Comment: 14 pages including 10 figures. To Physical Review B. Replaced after
corrections due to referees' remark
Speeds and arrival times of solar transients approximated by self-similar expanding circular fronts
The NASA STEREO mission opened up the possibility to forecast the arrival
times, speeds and directions of solar transients from outside the Sun-Earth
line. In particular, we are interested in predicting potentially geo-effective
Interplanetary Coronal Mass Ejections (ICMEs) from observations of density
structures at large observation angles from the Sun (with the STEREO
Heliospheric Imager instrument). We contribute to this endeavor by deriving
analytical formulas concerning a geometric correction for the ICME speed and
arrival time for the technique introduced by Davies et al. (2012, ApJ, in
press) called Self-Similar Expansion Fitting (SSEF). This model assumes that a
circle propagates outward, along a plane specified by a position angle (e.g.
the ecliptic), with constant angular half width (lambda). This is an extension
to earlier, more simple models: Fixed-Phi-Fitting (lambda = 0 degree) and
Harmonic Mean Fitting (lambda = 90 degree). This approach has the advantage
that it is possible to assess clearly, in contrast to previous models, if a
particular location in the heliosphere, such as a planet or spacecraft, might
be expected to be hit by the ICME front. Our correction formulas are especially
significant for glancing hits, where small differences in the direction greatly
influence the expected speeds (up to 100-200 km/s) and arrival times (up to two
days later than the apex). For very wide ICMEs (2 lambda > 120 degree), the
geometric correction becomes very similar to the one derived by M\"ostl et al.
(2011, ApJ, 741, id. 34) for the Harmonic Mean model. These analytic
expressions can also be used for empirical or analytical models to predict the
1 AU arrival time of an ICME by correcting for effects of hits by the flank
rather than the apex, if the width and direction of the ICME in a plane are
known and a circular geometry of the ICME front is assumed.Comment: 15 pages, 5 figures, accepted for publication in "Solar Physics
A Search for Selectrons and Squarks at HERA
Data from electron-proton collisions at a center-of-mass energy of 300 GeV
are used for a search for selectrons and squarks within the framework of the
minimal supersymmetric model. The decays of selectrons and squarks into the
lightest supersymmetric particle lead to final states with an electron and
hadrons accompanied by large missing energy and transverse momentum. No signal
is found and new bounds on the existence of these particles are derived. At 95%
confidence level the excluded region extends to 65 GeV for selectron and squark
masses, and to 40 GeV for the mass of the lightest supersymmetric particle.Comment: 13 pages, latex, 6 Figure
Accounting for International War: The State of the Discipline
In studies of war it is important to observe that the processes leading to so frequent an event as conflict are not necessarily those that lead to so infrequent an event as war. Also, many models fail to recognize that a phenomenon irregularly distributed in time and space, such as war, cannot be explained on the basis of relatively invariant phenomena. Much research on periodicity in the occurrence of war has yielded little result, suggesting that the direction should now be to focus on such variables as diffusion and contagion. Structural variables, such as bipolarity, show contradictory results with some clear inter-century differences. Bipolarity, some results suggest, might have different effects on different social entities. A considerable number of studies analysing dyadic variables show a clear connection between equal capabilities among contending nations and escalation of conflict into war. Finally, research into national attributes often points to strength and geographical location as important variables. In general, the article concludes, there is room for modest optimism, as research into the question of war is no longer moving in non-cumulative circles. Systematic research is producing results and there is even a discernible tendency of convergence, in spite of a great diversity in theoretical orientations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69148/2/10.1177_002234338101800101.pd
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