Subclinical cardiovascular disease and Systemic Sclerosis: A comparison between risk charts, quantification of coronary calcium and carotid ultrasonography.

BACKGROUND AND OBJECTIVES: Recently published population-based cohort studies have shown a high prevalence of cardiovascular disease in Systemic Sclerosis (SSc) patients. The aim of this study is to compare three different methods to measure cardiovascular risk in patients with scleroderma. METHODS: Forty-three SSc patients were included. A prospective study was performed for evaluation of cardiovascular risk and subclinical atheromatosis using 3 non-invasive methods: cardiovascular risk tables, carotid Doppler ultrasonography and quantification of coronary calcium by computerized tomography (CT). RESULTS: The cardiovascular risk charts for the Spanish population did not identify patients at high cardiovascular risk. Framingham-REGICOR identified 13 intermediate-risk patients. Twenty-two patients (51.2%) had plaques on carotid ultrasonography. We performed a ROC curve to identify the best cutoff point for the quantification of coronary artery calcium (CACscore), the value of CACscore > 28 AU (Agatston Units) had the highest sensitivity (73%) and specificity (81%) for the diagnosis of subclinical atheromatosis. In the multiple regression study, age and decreased HDL cholesterol levels were identified as independent factors for subclinical atherosclerotic disease. No disease-related factors were associated with increased subclinical arteriosclerosis. CONCLUSION: Carotid ultrasound and CACscore are useful for identifying subclinical atheromatosis in patients with SSc and are superior compared to risk charts used for general population. HDL cholesterol and age were independent factors for the presence of subclinical atherosclerotic disease. A carotid ultrasound or CT should be performed for early detection of subclinical atheromatosis if these factors are present.

On the infrared activation of the breathing mode of methane in ice.

The symmetric stretching vibration (breathing mode) of methane is forbidden in the infrared spectra of gases. However, it has been observed in the spectra of low-pressure ice mixtures of methane and water, studied as models for astronomical ices. We investigate the possible origin of the activation of this mode by means of solid state calculations of amorphous water (ASW) samples into which methane molecules are introduced. Activation is predicted either by the interaction of the CH4 and H2O molecules in pore walls or via a strong mode coupling that takes place between the breathing mode of CH4 and the O-H stretching mode of H2O when both vibrations coincide in frequency. These two mechanisms would be favored for low-density or high density ASW, respectively. A possible experimental observation of this activation in compact ASW is discussed.

On the mechanism of iodine oxide particle formation.

The formation of atmospherically relevant iodine oxides IxOy (x = 1,…,3, y = 1,…,7) has been studied experimentally using time-of-flight mass spectrometry combined with a soft ionisation source, complemented with ab initio electronic structure calculations of ionisation potentials and bond energies at a high level of theory presented in detail in the accompanying paper (Galvez et al., 2013). For the first time, direct experimental evidence of the I2Oy (y = 1,…,5) molecules in the gas phase has been obtained. These chemical species are observed alongside their precursors (IO and OIO) in experiments where large amounts of aerosol are also generated. The measured relative concentrations of the IxOy molecules and their dependence on ozone concentration have been investigated by using chemical modelling and rate theory calculations. It is concluded that I2O4 is the most plausible candidate to initiate nucleation, while the contribution of I2O5 in the initial steps is likely to be marginal. The absence of large I3Oy (y = 3,…,6) peaks in the mass spectra and the high stability of the I2O4-I2O4 dimer indicate that dimerisation of I2O4 is the key step in iodine oxide particle nucleation.

A theoretical study on the formation of iodine oxide aggregates and monohydrates.

Biotic and abiotic emissions of molecular iodine and iodocarbons from the sea or the ice surface and the intertidal zone to the coastal/polar marine boundary layer lead to the formation of iodine oxides, which subsequently nucleate forming iodine oxide particles (IOPs). Although the link between coastal iodine emissions and ultrafine aerosol bursts is well established, the details of the nucleation mechanism have not yet been elucidated. In this paper, results of a theoretical study of a range of potentially relevant aggregation reactions of different iodine oxides, as well as complexation with water molecules, are reported. Thermochemical properties of these reactions are obtained from high level ab initio correlated calculations including spin-orbit corrections. The results show that the nucleation path most likely proceeds through dimerisation of I2O4. It is also shown that water can hinder gas-to-particle conversion to some extent, although complexation with key iodine oxides does not remove enough of these to stop IOP formation. A consistent picture of this process emerges from the theoretical study presented here and the findings of a new laboratory study reported in the accompanying paper (Gomez Martin et al., 2013).

[Review of medication errors: a case in an intensive care unit]. / Revue des erreurs médicamenteuses (REMED) : une première en service de réanimation.

OBJECTIVE: The authors conducted for the first time a medication error review (REMED) following a medication error occurred in an intensive care unit. The aim of this study was to assess this first REMED. STUDY DESIGN: Descriptive study. METHODS: The analysis of the medication error, consisting in the administration of Clottafact(®) instead of Aclotine(®), was performed using the REMED method. RESULTS: The medication error was characterized as "proved error" and "missed before administration". Four main causes were identified: poor quality of drug storage, homophony between Aclotine(®) and Clottafact(®), non-compliance with good practices, and need of hemofiltration for the patient. At least, this REMED analysis led to the establishment of four improvements measures. CONCLUSION: The educational aspect of the REMED was clearly appreciated by all the different health care workers who participated to the analysis. Even if medication errors may occur at the different steps of the medication process, the REMED is a very good tool to improve the care quality and also to reduce the drug iatrogenic risk.

The structure and spectroscopy of cyanate and bicarbonate ions. Astrophysical implications.

Cyanate and bicarbonate are two ions that play active roles in many fields of physics and chemistry, including biological sciences and astrochemistry. We present here a comprehensive study of these species covering a range of phases and methodologies. We have performed theoretical calculations on the isolated ions and their hydrates with one to four water molecules, and in clusters with 15 water molecules. The predicted infrared spectra are compared with observed spectra from experiments where liquid droplets of their solutions are frozen at 14 K on a substrate, to mimic some astrophysical conditions. Crystals of cyanate and bicarbonate sodium and potassium salts are also studied experimental and theoretically. As well, the spontaneous decomposition of cyanate into bicarbonate is documented from the spectra of an aged solution. Finally, the possible astrophysical observation of bicarbonate in water-containing particles is discussed.

Formate ion: structure and spectroscopic properties.

The formate anion HCOO(-) is present in a multitude of systems of relevance, and it is characterized by its plasticity, adopting several different structures. This work provides a theoretical study of the ion focused on two of these structures, a crystal and an isolated species. Crystals of sodium formate and ammonium formate are studied using CASTEP, a solid-oriented computing package. Individual molecules of the same systems and of the formate and ammonium ions are also studied, using the Gaussian code at the MP2/aug-cc-pvTZ level. All theoretical calculations are contrasted by comparison to observed infrared spectra, recorded by using different techniques. In addition, a topological analysis of the bonding properties of the isolated molecules is presented.

Theoretical study of atmospheric clusters: HNO3-HCl-H2O.

Nitric acid, hydrochloric acid and water can form stable aggregates with atmospheric implications, for instance at the surface of polar stratospheric clouds. The structure, stability and chemical properties of these ternary complexes are studied by means of high level theoretical calculations (hybrid DFT B3LYP method along with aug-cc-pVQZ basis set). From the many possible systems that these molecules could form, only 15 are found to yield stable structures, well characterized by a minimum in their potential energy surfaces. These aggregates are studied in detail. They can be collected in three families, according to the role played by each species in the different hydrogen bonding links that result and provide the basis for the stabilization of the clusters. Water and HCl can be H-donors to almost every O atom of HNO(3), which in turn can donate its H atom to the other two molecules. Two special cases are found, one in which H(2)O plays a central role, and another with a three-dimensional structure, in contrast to the basically planar frame of the other clusters. Bonding properties are investigated for the whole series using AIM methods. The elongation of the H-Cl bond as a consequence of the aggregate creation is inspected in detail, as it may provide a clue to the lability of this molecule with implications in atmospheric processes. The Gibbs free energy calculated for these clusters shows that some of them could form spontaneously in the range of temperatures of the stratosphere.

Theoretical study on the structure of the BrO hydrates.

The hydrates of bromine monoxide, BrO(H2O)n, n = 1-4, have been studied by means of ab initio calculations at the B3LYP/aug-cc-pVTZ level of theory. These systems could be formed in the troposphere and participate in chemical reactions involved in the depletion of ozone. Several conformations are obtained and discussed for each of the hydrates mentioned. Two rather different intermolecular interactions are found, namely, conventional hydrogen bonding and Br...O associations. In contrast with a more traditional point of view in which hydrogen bonds could be assumed as the preferential interaction for the formation of these complexes, it is the Br...O association which yields the most stable conformations. Equilibrium geometries, harmonic frequencies, and relative energies have been calculated for the bromine monoxide hydrates for the first time. The theoretical binding energies indicate that the stabilization of the hydrates increases with the number of water molecules added. Cooperative effects are suggested to play a significant role in this stabilization. An analysis of relevant properties depending on the electron density in the bond critical points of the Br...O associations has been done for the first time, showing characteristic features of this interaction in comparison with the hydrogen bonds formed.

Theoretical study of stratospheric relevant anions: nitrate-nitric acid complexes.

The ion complexes NO3-(HNO3)n, n = 1-3, have been studied by means of ab initio calculations at the B3LYP/aug-cc-pVTZ level of theory. These systems are the most abundant anionic clusters below approximately 30 km altitude in the stratosphere and also in the upper troposphere. These complexes display short strong hydrogen bonds, which should be considered to explain their abundance in the atmosphere. Equilibrium geometries, harmonic frequencies, relative energies, and thermochemical data have been calculated for these anions for the first time. The calculations indicate small differences of energy in the variation of the two nitrate groups from planarity to an almost perpendicular form for n = 1. Planar geometries are found for n = 2 and 3 to give rise to a highly symmetric C(3h) NO3-(HNO3)3. In all the cases, binding energies close to those of covalent compounds are estimated. When experimental data are available, good correlations are found with our results.

Variation of geometries and electron properties along proton transfer in strong hydrogen-bond complexes.

Proton transfer in hydrogen-bond systems formed by 4-methylimidazole in both neutral and protonated cationic forms and by acetate anion are studied by means of MP26-311++G(d,p) ab initio calculations. These two complexes model the histidine (neutral and protonated)-aspartate diad present in the active sites of enzymes the catalytic mechanism of which involves the formation of strong hydrogen bonds. We investigate the evolution of geometries, natural bond orbital populations of bonds and electron lone pairs, topological descriptors of the electron density, and spatial distributions of the electron localization function along the process N-H...O-->N...H...O-->N...H-O, which represents the stages of the H-transfer. Except for a sudden change in the population of electron lone pairs in N and O at the middle N...H...O stage, all the properties analyzed show a smooth continuous behavior along the covalent --> hydrogen bond transit inherent to the transfer, without any discontinuity that could identify a formation or breaking of the hydrogen bond. This way, the distinction between covalent or hydrogen-bonding features is associated to subtle electron rearrangement at the intermolecular space.

[Infrared spectrophotometry: a versatile analytical tool in hospital pharmacy]. / La spectrométrie d'absorption moléculaire dans l'infrarouge: un équipement analytique polyvalent pour la pharmacie hospitalière.

Pharmacy services in healthcare facilities have increasing analytical needs, as frequently recalled by good practices guidelines (hospital pharmacy good practices, hospital pharmaceutical preparations good practices). Various analytical methods can be employed, from spot tests to the most recent chromatographic methods. The purpose of this paper is to demonstrate, with two concrete examples, the versatility and pertinence of one of these analytical methods: infrared spectrophotometry. We describe two current applications, used in a hospital pharmacy service: identification of pharmaceutical raw material and dose control of cytotoxic injectable preparations.

The hemodynamic effects of potassium deficiency in the dog.

Potassium deficiency for 3 weeks in dogs caused 374 +/- 38 mEq of sodium retention with increase in body weight, plasma volume, and inulin space. Cardiac output increased from 3.7 +/- 0.6 to 5 +/- 0.6 liters/min (P less than 0.02) and systemic vascular resistance decreased from 3,050 +/- 590 to 2,000 +/- 286 dynes/cm per sec2 (P less than 0.05). Plasma renin activity (PRA) increased from 0.4 +/- 0.1 to 17.2 +/- 0.9 ng/ml per hour (P less than 0.01) without change in plasma aldosterone. Angiotensin sensitivity decreased from a rise of 37 +/- 4 mm Hg in mean arterial pressure (MAP) to 10 ng/kg per min before potassium depletion to a rise of 10 +/- 2 mm Hg after hypokalemia. Urinary prostaglandin E (PGE) excretion increased from control values of 1,224 to 1,556 ng/day to 9,352 +/- 3,670 after 21 days of hypokalemia (P less than 0.01). Indomethacin, 150 mg a day for 3 days, decreased urinary PGE to control values as PRA decreased from 17.2 +/- 5.9 to 1.1 +/- .3 ng/ml per hour and angiotensin sensitivity was partially restored. These findings indicate that hypokalemia increased urinary PGE with extracellular fluid volume expansion, decreased sensitivity to angiotensin and increase in PRA.

Studies of the mechanism of contralateral polyuria after renal artery stenosis.

Acute renal artery stenosis in hydropenic dogs caused a contralateral increase in urine volume and free water clearance without change in glomerular filtration, renal blood flow, or osmolar clearance. The increase in urine volume was not dependent on the development of hypertension since it occurred in animals pretreated with trimethaphan but was dependent upon angiotensin since it was presented with angiotensin blockade with Saralasin. The effect was not caused by angiotensin inhibiting antidiuretic hormone release since the polyuria occurred in hypophysectomized animals receiving a constant infusion of 10 muU/kg per min of aqueous Pitressin. Since the rise in urine volume was associated with an increase in renal vein prostaglandin E concentration and was prevented by pretreatment with indomethacin (5 mg/kg) the results suggest that the rise in plasma angiotensin after renal artery stenosis causes an increase in contralateral prostaglandin E synthesis with resultant antagonism to antidiuretic hormone at the collecting tubule.