Role of Amoxicillin Serum Levels for Successful Prophylaxis of Experimental Endocarditis Due to Tolerant Streptococci

The importance of amoxicillin serum profiles for successful prophylaxis of experimental endocarditis in rats was assessed. Animals with catheter-induced vegetations were challenged intravenously with large inocula of Streptococcus sanguis and received one of the following amoxicillin dosages: single or multiple bolus injection of 40 mg/kg; 40 mg/kg administered as a continuous infusion over 12 h; or either 9 or 18 mg/kg administered over 12 or 24 h, respectively. The regimen producing a single transient high peak serum level failed to prevent experimental endocarditis; in contrast, a second injection 6 h after the first resulted in successful prophylaxis. Likewise, the three regimens of continuous, relatively low-dose regimens prevented infections. Thus, the most important parameter for successful prophylaxis was the duration of inhibitory concentration of the drug in the serum. The total dose of antibiotic, the peak serum levels, or the area-under-the-curve values were not predictive of successful prophylaxi

Nephrotoxicity, high frequency ototoxicity, efficacy and serum kinetics of once versus thrice daily dosing of netilmicin in patients with serious infections

The effect of dosing regimen on nephrotoxicity, high frequency ototoxicity, efficacy and serum kinetics was studied in a prospective, randomised clinical study. Therapy was started with total daily doses of 6 mg/kg given once (od) or thrice (tid) daily to 56 and 57 patients, respectively. Subsequent doses were adjusted according to serum levels. No major differences in toxicity or efficacy were noticed between od and tid regimens: clinical failures occurred in two and two patients, four and five patients suffered from a decrease of ≥20 dB at least unilaterally at one frequency between 8 and 18 kHz, six and seven patients had a >25 μmol/L or >25% increase in serum creatinine, respectively. Serum creatinine or creatinine clearance did not change significantly during either therapy. Major differences between the two study groups were limited to pharmacokinetic parameters. Od dosing resulted in higher peak (mean of 21.6 vs 7.2 mg/L) and lower trough levels (0.5 vs 1.4mg/L). Half-lives of netilmicin determined between 1 and 8 h increased significantly during therapy with tid (from a mean of 2.75 to a mean of 3.33 h, P<0.01) but not significantly with od (rise from 2.8 to 3.03 h). Much longer half-lives were determined between 8 and 24 h in the od group (mean of 5.7 h, P<0.01). In conclusion, only minimal differences in toxicity and efficacy were observed. Their clinical relevance appears to be minima

Improved timber harvest techniques maintain biodiversity in tropical forests

Tropical forests are selectively logged at 20 times the rate at which they are cleared, and at least a fifth have already been disturbed in this way. In a recent pan-tropical assessment, Burivalova et al. demonstrate the importance of logging intensity as a driver of biodiversity decline in timber estates. Their analyses reveal that species richness of some taxa could decline by 50% at harvest intensities of 38 m3 ha-1. However, they did not consider the extraction techniques that lead to these intensities. Here, we conduct a complementary meta-analysis of assemblage responses to differing logging practices: conventional logging and reduced-impact logging. We show that biodiversity impacts are markedly less severe in forests that utilise reduced-impact logging, compared to those using conventional methods. While supporting the initial findings of Burivalova et al., we go on to demonstrate that best practice forestry techniques curtail the effects of timber extraction regardless of intensity. Therefore, harvest intensities are not always indicative of actual disturbance levels resulting from logging. Accordingly, forest managers and conservationists should advocate practices that offer reduced collateral damage through best practice extraction methods, such as those used in reduced-impact logging. Large-scale implementation of this approach would lead to improved conservation values in the 4 million km2 of tropical forests that are earmarked for timber extraction

Testing the equivalence principle: why and how?

Part of the theoretical motivation for improving the present level of testing of the equivalence principle is reviewed. The general rationale for optimizing the choice of pairs of materials to be tested is presented. One introduces a simplified rationale based on a trichotomy of competing classes of theoretical models.Comment: 11 pages, Latex, uses ioplppt.sty, submitted to Class. Quantum Gra

Impact of electronic reminders on venous thromboprophylaxis after admissions and transfers

Objective Clinical decision support has the potential to improve prevention of venous thromboembolism (VTE). The purpose of this prospective study was to analyze the effect of electronic reminders on thromboprophylaxis rates in wards to which patients were admitted and transferred. The latter was of particular interest since patient handoffs are considered to be critical safety issues. Methods The trial involved two study periods in the six departments of a university hospital, three of which were randomly assigned to the intervention group displaying reminders during the second period. At 6 h after admission or transfer, the algorithm checked for prophylaxis orders within 0-30 h of the patient's arrival, increasing the specificity of the displayed reminders. Results The significant impact of the reminders could be seen by prophylaxis orders placed 6-24 h after admission (increasing from 8.6% (223/2579) to 12% (307/2555); p<0.0001) and transfer (increasing from 2.4% (39/1616) to 3.7% (63/1682); p=0.034). In admission wards, the rate of thromboprophylaxis increased from 62.4% to 67.7% (p<0.0001), and in transfer wards it increased from 80.2% to 84.3% (p=0.0022). Overall, the rate of prophylaxis significantly increased in the intervention group from 69.2% to 74.3% (p<0.0001). No significant changes were observed in the control group. Postponing prophylaxis checks to 6 h after admissions and transfers reduced the number of reminders by 62% and thereby minimized the risk of alert fatigue. Conclusions The reminders improved awareness of VTE prevention in both admission and transfer wards. This approach may contribute to better quality of care and safer patient handoff

The Positron Decay of F18

[No abstract.

Dark-Matter-Induced Weak Equivalence Principle Violation

A long-range fifth force coupled to dark matter can induce a coupling to ordinary matter if the dark matter interacts with Standard Model fields. We consider constraints on such a scenario from both astrophysical observations and laboratory experiments. We also examine the case where the dark matter is a weakly interacting massive particle, and derive relations between the coupling to dark matter and the coupling to ordinary matter for different models. Currently, this scenario is most tightly constrained by galactic dynamics, but improvements in Eotvos experiments can probe unconstrained regions of parameter space.Comment: 4 page

Phenomenology of the Equivalence Principle with Light Scalars

Light scalar particles with couplings of sub-gravitational strength, which can generically be called 'dilatons', can produce violations of the equivalence principle. However, in order to understand experimental sensitivities one must know the coupling of these scalars to atomic systems. We report here on a study of the required couplings. We give a general Lagrangian with five independent dilaton parameters and calculate the "dilaton charge" of atomic systems for each of these. Two combinations are particularly important. One is due to the variations in the nuclear binding energy, with a sensitivity scaling with the atomic number as $A^{-1/3}$. The other is due to electromagnetism. We compare limits on the dilaton parameters from existing experiments.Comment: 5 page

Nuclear Gamma-Radiation of Cu61

The positron spectrum of Cu61 has been examined recently by Cook and Langer with a large magnetic spectrometer. The experimental curves of these authors show a deviation from the Fermi distribution which is much larger than for Cu64 and it seems possible that not all of this deviation arises from the instrumental factors. It is pointed out by different authors that Cu61 does not emit nuclear gamma-rays which means that the spectrum of Cu61 must be simple. On the other hand the measurements of Cook and Langer can hardly be understood without the assumption of a complex spectrum. To examine this discrepancy, we started a search for gamma-radiation in Cu61

Northern Sourced Water dominated the Atlantic Ocean during the Last Glacial Maximum

Increased carbon sequestration in the ocean subsurface is commonly assumed to have been one of the main causes responsible for lower glacial atmospheric CO2 concentrations. Remineralized carbon must have been stored away from the atmosphere for thousands of years, yet the water mass structure accommodating such increased carbon storage continues to be debated. Here, we present new sediment-derived bottom-water neodymium isotope records that allow fingerprinting of water masses and provide a more complete picture of the Atlantic Meridional Overturning Circulation geometry during the Last Glacial Maximum. These results suggest that the vertical and meridional structure of the Atlantic water mass distribution only experienced minor changes since the last ice age. In particular, we find no compelling evidence supporting glacial southern-sourced water substantially expanding to shallower depths and farther into the Northern Hemisphere than today, which had been previously inferred from stable carbon isotope (δ13C) reconstructions. We argue that depleted δ13C values observed in the deep Northwest Atlantic do not necessarily indicate the presence of southern-sourced water. Instead, these values may represent a northern-sourced water mass with lower than modern preformed δ13C values that were further modified downstream by increased sequestration of remineralized carbon, facilitated by a more sluggish glacial deep circulation, corroborating previous evidence