Influence of age and renal disease on aminoglycoside dosage

New guidelines for the administration of amikacin are presented for neonates, children and adults, with normal or impaired, stable or changing renal function. The dose is calculated according to the lean body mass, which can be estimated from weight, height and sex of the patient. The dosing interval is calculated from the predicted drug half-life, which is derived from creatinine clearance normalized to 50 kg lean body mass (LBM). A formula is presented to estimate directly the Ccr in ml/min per 50 kg LBM, based only upon serum creatinine concentrations and the age of the subject. Two electronic pocket calculators which contain the dosage guidelines of amikacin are also described. Les auteurs présentent de nouvelles recommandations pour la détermination de la posologie de l'amikacine chez les nouveau-nés, les enfants et les adultes dans le cas de fonction rénale normale ou altérée, de fuçon stable ou variable. La dose eat calculée selon la masse corporelle ‘dégraisséc' qui eat évaluée en fonction du poids, de la taille et du sexe du malade. L'intervalle entre les doses est calculé à partir de la demi-vie estimée selon la valeur de la clairance de la créatinine rapportée à 50 kg de masse corporelle ‘dégraissée'. Une formule eat donnée, qui permet de calculer directement la clairance de la créatinine en ml/min/50 kg de masse corporelle dégraissée basée uniquement sur la créatininémie et l'âgc du sujet. Deux calculateurs de poche programmées pour le calcul de la posologie de l'amikacine sont décrite

Gas Phase dynamics of spiropyrans and spirooxazines molecules

The gas-phase dynamics of two classes of photochromic molecules, three spiropyrans and one spirooxazine, have been investigated here using both time-resolved mass spectrometry and photoelectron spectroscopy approaches. It is, to our knowledge, the first gas-phase experiment done of these kinds of molecules. The molecules are excited at 266 nm and probed at 800 nm. The comparison of the dynamics of these four molecules has been used to propose a sequential photoisomerization mechanism involving four steps occurring in the first 100 ps. Each of these steps is discussed and related to the observed condensed-phase dynamics and to theoretical calculations

Time resolved observation of multiple electronic configurations in the electronic relaxation of isolated molecules by photoelectron imaging

Contains fulltext : 60272.pdf (preprint version ) (Open Access

Acute hepatitis in three patients with systemic juvenile idiopathic arthritis taking interleukin-1 receptor antagonist

<p>Abstract</p> <p>Purpose</p> <p>We investigated the etiology of acute hepatitis in three children with systemic Juvenile Idiopathic Arthritis (sJIA) taking Interleukin-1 receptor antagonist (IL1RA).</p> <p>Methods</p> <p>Laboratory and clinical data for three children with sJIA diagnosed at ages 13 months to 8 years who developed acute hepatitis during treatment with IL1RA were reviewed for evidence of sJIA flare, infection, macrophage activation syndrome (MAS), malignancy, and drug reaction.</p> <p>Results</p> <p>In all patients, hepatitis persisted despite cessation of known hepatotoxic drugs and in absence of known infectious triggers, until discontinuation of IL1RA. Liver biopsies had mixed inflammatory infiltrates with associated hepatocellular injury suggestive of an exogenous trigger. At the time of hepatitis, laboratory data and liver biopsies were not characteristic of MAS. In two patients, transaminitis resolved within one week of discontinuing IL1RA, the third improved dramatically in one month.</p> <p>Conclusions</p> <p>Although sJIA symptoms improved significantly on IL1RA, it appeared that IL1RA contributed to the development of acute hepatitis. Hepatitis possibly occurred as a result of an altered immune response to a typical childhood infection while on IL1RA. Alternatively, hepatitis could have represented an atypical presentation of MAS in patients with sJIA taking IL1RA. Further investigation is warranted to determine how anti-IL1 therapies alter immune responsiveness to exogenous triggers in patients with immune dysfunction such as sJIA. Our patients suggest that close monitoring for hepatic and other toxicities is indicated when treating with IL1RA.</p

Optimizing allocation of curricular content across the undergraduate & graduate medical education continuum

BACKGROUND: Medical educators struggle to incorporate socio-cultural topics into crowded curricula. The continuum of learning includes undergraduate and graduate medical education. Utilizing an exemplar socio-cultural topic, we studied the feasibility of achieving expert consensus among two groups of faculty (experts in medical education and experts in social determinants of health) on which aspects of the topic could be taught during undergraduate versus graduate medical education. METHODS: A modified Delphi method was used to generate expert consensus on which learning objectives of social determinants of health are best taught at each stage of medical education. Delphi respondents included experts in medical education or social determinants of health. A survey was created using nationally published criteria for social determinants of health learning objectives. Respondents were asked 1) which learning objectives were necessary for every physician (irrespective of specialty) to develop competence upon completion of medical training and 2) when the learning objective should be taught. Respondents were also asked an open-ended question on how they made the determination of when in the medical education continuum the learning objective should be taught. RESULTS: 26 out of 55 experts (13 social determinants of health and 13 education experts) responded to all 3 Delphi rounds. Experts evaluated a total of 49 learning objectives and were able to achieve consensus for at least one of the two research questions for 45 of 49 (92%) learning objectives. 50% more learning objectives reached consensus for inclusion in undergraduate (n = 21) versus graduate medical education (n = 14). CONCLUSIONS: A modified Delphi technique demonstrated that experts could identify key learning objectives of social determinants of health needed by all physicians and allocate content along the undergraduate and graduate medical education continuum. This approach could serve as a model for similar socio-cultural content. Future work should employ a qualitative approach to capture principles utilized by experts when making these decisions

A Multipronged Comparative Study of the Ultraviolet Photochemistry of 2-, 3-, and 4-Chlorophenol in the Gas Phase

The S1(1ππ*) state of the (dominant) syn-conformer of 2-chlorophenol (2-ClPhOH) in the gas phase has a subpicosecond lifetime, whereas the corresponding S1 states of 3- and 4-ClPhOH have lifetimes that are, respectively, ∼2 and ∼3-orders of magnitude longer. A range of experimental techniques–electronic spectroscopy, ultrafast time-resolved photoion and photoelectron spectroscopies, H Rydberg atom photofragment translational spectroscopy, velocity map imaging, and time-resolved Fourier transform infrared emission spectroscopy–as well as electronic structure calculations (of key regions of the multidimensional ground (S0) state potential energy surface (PES) and selected cuts through the first few excited singlet PESs) have been used in the quest to explain these striking differences in excited state lifetime. The intramolecular O–H···Cl hydrogen bond specific to syn-2-ClPhOH is key. It encourages partial charge transfer and preferential stabilization of the diabatic 1πσ* potential (relative to that of the 1ππ* state) upon stretching the C–Cl bond, with the result that initial C–Cl bond extension on the adiabatic S1 PES offers an essentially barrierless internal conversion pathway via regions of conical intersection with the S0 PES. Intramolecular hydrogen bonding is thus seen to facilitate the type of heterolytic dissociation more typically encountered in solution studies