Polycyclic Aromatic Hydrocarbons (PAHs) in Interstellar Ices: A Computational Study into How the Ice Matrix Influences the Ionic State of PAH Photoproducts.

It has been experimentally observed that water-ice-embedded polycyclic aromatic hydrocarbons (PAHs) form radical cations when exposed to vacuum UV irradiation, whereas ammonia-embedded PAHs lead to the formation of radical anions. In this study, we explain this phenomenon by investigating the fundamental electronic differences between water and ammonia, the implications of these differences on the PAH-water and PAH-ammonia interaction, and the possible ionization pathways in these complexes using density functional theory (DFT) computations. In the framework of the Kohn-Sham molecular orbital (MO) theory, we show that the ionic state of the PAH photoproducts results from the degree of occupied-occupied MO mixing between the PAHs and the matrix molecules. When interacting with the PAH, the lone pair-type highest occupied molecular orbital (HOMO) of water has poor orbital overlap and is too low in energy to mix with the filled π-orbitals of the PAH. As the lone-pair HOMO of ammonia is significantly higher in energy and has better overlap with filled π-orbitals of the PAH, the subsequent Pauli repulsion leads to mixed MOs with both PAH and ammonia character. By time-dependent DFT calculations, we demonstrate that the formation of mixed PAH-ammonia MOs opens alternative charge-transfer excitation pathways as now electronic density from ammonia can be transferred to unoccupied PAH levels, yielding anionic PAHs. As this pathway is much less available for water-embedded PAHs, charge transfer mainly occurs from localized PAH MOs to mixed PAH-water virtual levels, leading to cationic PAHs.

Paciente afectado de psoriasis, quien desarrolla una enfermedad ampollar intercurrente: a propósito de un caso

RESUMEN La asociación y coexistencia de psoriasis en placas y penfigoide ampollar (Psoriasis-PA) es una variante clínica poco frecuente. Predomina en el sexo masculino, después de los 60 años de edad. En general, los pacientes ya cuentan con el antecedente de psoriasis y posteriormente se agrega la enfermedad ampollar, con un intervalo promedio de 20 años. Aunque la etiopatogenia aún no se encuentra del todo establecida, se identifican factores desencadenantes tales comoPUVA, fármacos e infecciones. Las opciones terapéuticas consisten en esquemas de monoterapia obiterapia con asociación de corticoesteroides orales e inmunosupresores como el metotrexato (MTX) con evolución favorable en la mayoría de los casos. Se presenta el caso de un paciente masculino, de 52 años de edad con psoriasis vulgar de tres años de evolución y lareciente aparición de penfigoide ampollar.

ABSTRACT The association and coexistence of plaque psoriasis and bullous pemphigoid is a rare clinical variant. It predominates in the male sex, after 60 years old. In general, patients already have a history of psoriasis and then bullous disease is added, with an average interval of 20 years. Although the pathogenesis is not yet fully established, it identifies triggers such as PUVA, drugs, and infections. Therapeutic options consist of monotherapy or combination regimens of systemic corticosteroids and other immunosuppressants such as methotrexate, with favorable evolution in most cases. We present the case of a 52-year-old male patient with 3-year history of vulgar psoriasis and recent appearance of bullous pemphigoid.

Quantifying electronic similarities between NHC-gold(i) complexes and their isolobal imidazolium precursors.

A series of NHC-gold(i) (NHC = N-heterocyclic carbene) complexes has been studied by DFT calculations, enabling comparison of electronic and NMR behaviour with related protonated and free NHC molecules. Based on calculations, the NMR resonances of the carbenic C2 carbon atom in [Au(NHC)(Cl)] and [NHC(H)][Cl] exhibit increased shielding when compared to the free N-heterocyclic carbenes by an average of 46.6 ± 2.2 and 73.7 ± 4.3 ppm, respectively. A similar trend is observed when analysing the paramagnetic term of the magnetic shielding tensor. Although gold(i) and proton are considered isolobal fragments, imidazolium compounds lack π-backdonation due to the energetic unavailability of d-orbitals in H+. We propose that NHC-gold(i) complexes exhibit important π-backdonation irrespective of the relative amount of σ-donation between the NHC and gold(i)-X (X = anionic ligand) moieties in Au-NHC complexes. Interestingly, a correlation exists between the calculated shielding for gold (197Au) and the π-donation and π-backdonation contributions. We describe that this correlation also exists when analysing the σ-backdonation term, a property generally ignored yet representing a significant energetic contribution to the stability of the C2-Au bond.

Regression analysis of properties of [Au(IPr)(CHR2)] complexes.

New [Au(IPr)(CHR2)] complexes have been synthesised through protonolysis reactions of [Au(IPr)(OH)] with moderately acidic substrates, CH2R2. An array of spectroscopic (IR and NMR), structural (X-ray), electronic (DFT) and experimental (reactivity) parameters was collected to quantify the variation in stereoelectronic properties of these new and previously reported [Au(IPr)(CHR2)] complexes. Variation of the R substituents on the carbanion ligands (CHR2-) was found to have a crucial impact on parameters characterising the resulting gold complexes. A regression analysis of both experimental and modelled parameters, guided by network analysis techniques, produced linear models that supported trends within the [Au(IPr)(CHR2)] complexes.

Stereoselective Gold(I)-Catalyzed Intermolecular Hydroalkoxlation of Alkynes.

We report the use of cationic gold complexes [Au(NHC)(CH3CN)][BF4] and [{Au(NHC)}2(µ-OH)][BF4] (NHC = N-heterocyclic carbene) as highly active catalysts in the solvent-free hydroalkoxylation of internal alkynes using primary and secondary alcohols. Using this simple protocol, a broad range of (Z)-vinyl ethers were obtained in excellent yields and high stereoselectivities. The methodology allows for the use of catalyst loadings as low as 200 ppm for the addition of primary alcohols to internal alkynes (TON = 35 000, TOF = 2188 h-1).

Networks of passive competition between multiple self-ordering proto-replicators and the effect of primitive membranes.

The emergence of informational replicators was fundamental to the origin of life and self-ordering proto-replicators provide an abstract, simulation based mechanism for a possible intermediary step in their development. Single systems enabled the dynamic self-ordering of generalised subunits into coherent and mobile structures, without the pre-existence of templates, replicators or functional catalysts. Paired systems linked via probabilistic, inter-system structural movement exhibited passive competition for subunits (which produced a new level of self-ordering dependent upon the systems' relative self-ordering capabilities) and the existence of primitive membranes increased this effect. This discussion naturally extends this approach to a simultaneous linking of multiple systems. Initially for various fixed numbers of subunits, 12 simultaneously linked self-ordering proto-replicators were studied (with and without primitive membranes). Then for the same underlying systems and three rates of increase, subunits were randomly added to give subunit ranges equivalent to the fixed cases. The results show an interacting network of inter-system passive competition, which created clear orderings of environmental dominance, the range of which was increased by primitive membranes. The simulations with increasing numbers of subunits provided approximations to those with fixed numbers and potentially give access to multiple sample points for future simulations with significantly greater numbers of subunits.

Passive competition between pairs of self-ordering proto-replicators and the effect of primitive membranes.

Self-ordering proto-replicators provide an abstract, simulation based investigation of a possible intermediary step in the development of informational replicators. They involve the dynamic self-ordering of generalised subunits of at least two types into coherent and mobile structures, and do not require the preexistence of templates, replicators or functional catalysts. The following discussion naturally extends this approach to include pairs of such systems linked via a probabilistic, inter-system movement of structures. Initially for two specific forms of self-ordering proto-replicator, various types of probabilistic movement were studied, both with and without a simple model of a primitive membrane. Then for a specific probabilistic movement, which was again considered with and without membranes, different pairings of twelve forms of self-ordering proto-replicators were studied. The results show that the systems exhibited a form of passive competition for subunits and that this produced a new level of multi-system self-ordering that depended upon the relative self-ordering capabilities of the individual systems. This effect was also found to be significantly more pronounced for those systems that included the primitive membranes. The implications for the origins of life were then considered.

Self-organizing proto-replicators and the origin of life.

Standard theories suggest that the first informational replicator involved RNA molecules (or a more primitive analogue) and that a preliminary step for the development of such replicating systems may have been the emergence of subunits capable of forming chains and interchain pairings. Following these hypotheses, this discussion describes various abstract simulations designed to investigate the structures resulting from such interactions for generalised subunits. Three classes of pairing strategy were considered for a range of subunit concentrations. The resulting dynamic self-organization of the systems produced high levels of structural complexity (some at low subunit concentrations and in the presence of disruptive subunits) and a significantly increased percentage of complementary base pairing (particularly in the more substantial structures). These properties of the systems, which did not require pre-existing replicators, templates or functional catalysts, were shown to be sensitive to the form of pairing strategy, subunit concentrations and various conditions that could theoretically be altered by products of the systems. Though no systems behaved as a replicator, some possessed collections of properties from which a replicating system might theoretically be constructed without requiring the introduction of additional classes of properties. The implications of such systems were considered with respect to the origin of life.

Confirmation of quantitative trait loci affecting fatness in chickens.

In this report we describe the analysis of an advanced intercross line (AIL) to confirm the quantitative trait locus (QTL) regions found for fatness traits in a previous study. QTL analysis was performed on chromosomes 1, 3, 4, 15, 18, and 27. The AIL was created by random intercrossing in each generation from generation 2 (G(2)) onwards until generation 9 (G(9)) was reached. QTL for abdominal fat weight (AFW) and/or percentage abdominal fat (AF%) on chromosomes 1, 3 and 27 were confirmed in the G(9) population. In addition, evidence for QTL for body weight at the age of 5 (BW5) and 7 (BW7) weeks and for the percentage of intramuscular fat (IF%) were found on chromosomes 1, 3, 15, and 27. Significant evidence for QTL was detected on chromosome 1 for BW5 and BW7. Suggestive evidence was found on chromosome 1 for AFW, AF% and IF%, on chromosome 15 for BW5, and on chromosome 27 for AF% and IF%. Furthermore, evidence on the chromosome-wise level was found on chromosome 3 for AFW, AF%, and BW7 and on chromosome 27 for BW5. For chromosomes 4 and 18, test statistics did not exceed the significance threshold.

Successful administration of quinupristin/dalfopristin in the outpatient setting.

Intravenous administration of quinupristin/dalfopristin outside the hospital setting has not been reported previously. We describe 37 outpatients receiving quinupristin/dalfopristin iv for infections including osteomyelitis, bacteraemia, abscesses and cellulitis. The most frequent aetiological pathogens found were Enterococcus faecium, Staphylococcus aureus and coagulase-negative staphylococci. Patients received an average of 9 days therapy as inpatients and 22 days as outpatients. Quinupristin/dalfopristin was administered using various access devices, most commonly peripherally inserted central catheters and tunnelled central catheters. The bacteriological and clinical success rates were both 89.2%. Five patients were readmitted to hospital; one patient developed catheter-related bacteraemia. The most frequently reported non-venous adverse events were nausea (18.9% of patients), myalgia (18.9%) and arthralgia (13.5%). Sixteen patients experienced venous access-related events, most commonly infusion pain, oedema and phlebitis. In this group of patients, for those who had difficult-to-treat infections, intravenous quinupristin/dalfopristin therapy was generally effective and safe outside the hospital setting.

Sensitivity to sparfloxacin and other antibiotics, of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis strains isolated from adult patients with community-acquired lower respiratory tract infections: a European multicentre study. SPAR Study Group. Surveillance Programme of Antibiotic Resistance.

A survey of resistance to sparfloxacin was carried out in ten European countries, namely Slovakia, France, Germany, Great Britain, Hungary, the Republic of Ireland, Italy, The Netherlands, Portugal and Spain. Respiratory samples were collected from 4297 patients with lower respiratory tract infections and cultured for the presence of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. Altogether 2101 strains were isolated and tested for their susceptibility to sparfloxacin, ciprofloxacin, erythromycin, tetracycline and penicillin G (S. pneumoniae) or amoxycillin (H. influenzae and M. catarrhalis). Each country tested strains using methods commonly used in that country, and with breakpoints selected based on those used in that country. Penicillin resistance in pneumococci was seen in those countries in which it had been reported previously, namely Spain, France and Hungary. Only four strains of pneumococci were resistant to sparfloxacin (MIC > or = 2 mg/L), while ciprofloxacin-resistant strains were isolated more frequently, particularly in the Republic of Ireland and Hungary. Almost all of the strains of H. influenzae tested were resistant to erythromycin, (MIC50 > or = 4 mg/L), but all strains were highly sensitive to sparfloxacin (MIC90 < or = 0.06 mg/L). The number of strains of H. influenzae producing beta-lactamase varied between countries, whereas most strains of M. catarrhalis produced beta-lactamase. In M. catarrhalis, erythromycin and tetracycline resistance was rare, but sensitivity to amoxycillin varied. Sparfloxacin was particularly active against H. influenzae and M. catarrhalis, and was the most active compound tested. Overall, the activity of sparfloxacin was greater than that of ciprofloxacin against all three pathogens, and resistance to it was rare.

Chain reactions linking acorns to gypsy moth outbreaks and Lyme disease risk.

In eastern U.S. oak forests, defoliation by gypsy moths and the risk of Lyme disease are determined by interactions among acorns, white-footed mice, moths, deer, and ticks. Experimental removal of mice, which eat moth pupae, demonstrated that moth outbreaks are caused by reductions in mouse density that occur when there are no acorns. Experimental acorn addition increased mouse density. Acorn addition also increased densities of black-legged ticks, evidently by attracting deer, which are key tick hosts. Mice are primarily responsible for infecting ticks with the Lyme disease agent. The results have important implications for predicting and managing forest health and human health.

[Echocardiography in pulmonary embolism]. / L'échocardiographie dans l'embolie pulmonaire.

Transthoracic echocardiography rarely confirms a diagnosis of pulmonary embolism by visualizing a thrombus in the pulmonary artery or right heart chambers. However, easily observed morphological and Doppler abnormalities may result from acute pulmonary hypertension: dilatation of the right heart chambers, a very sensitive and reliable sign of severe pulmonary embolism when the ratio of the right/left ventricular dimension > 0.6: abnormal interventricular septal contraction, a very specific sign of massive pulmonary embolism, and increased systolic pulmonary artery pressure. Transthoracic echocardiography allows evaluation of the severity of pulmonary embolism but it is difficult to orientate treatment on Doppler echocardiographic data alone. Transoesophageal echocardiography is a sensitive, specific and well-tolerated investigative method for the detection of proximal emboli in patients with massive pulmonary embolism. The investigation is rapid and can be carried out at the bedside, allowing confirmation of the diagnosis in two thirds of cases and the institution of thrombolytic or surgical therapy without the need for pulmonary angiography. Doppler echocardiography is also useful for following up the haemodynamic changes and the regression of acute cor pulmonale after thrombolysis.

[Anticoagulant therapy in pulmonary embolism]. / Traitements anticoagulants dans l'embolie pulmonaire.

Venous thrombosis and pulmonary embolism are the two faces of thromboembolic disease. In over 90% of cases, the initial treatment of the pulmonary embolism is anticoagulant therapy, the necessity and efficacy of which were demonstrated over 30 years ago with a reduction of mortality of 25 to 6%. Intravenous heparin relayed rapidly (1st to 3rd day) is still the conventional treatment protocol. Heparin therapy adapted to the result of the activated cephalin time (two to three times the control value) and oral vitamin K antagonists with a dosage adapted to keep the International Normalized Ratio between 2 and 3 is the safest and most effective treatment to date. The efficacy is shown by the low rate of recurrency, about 5% under anticoagulant therapy, lethal recurrence being very rare (less than 1%), and safety is attested by the low rate of severe bleeding complications (3 to 5%). The introduction of low molecular weight heparin and the excellent results observed in the treatment of deep vein thrombosis will probably lead to rapid extension of its indications to mild or moderate but haemodynamically well-tolerated pulmonary embolism. Hirudine and heparinoids will probably be the next step in the treatment of pulmonary embolism.

[Pulmonary embolism: which thrombolytic should be chosen?]. / Embolie pulmonaire: quel thrombolytique choisir?

A consensus has been reached in the last few years on the validity of the indication of thrombolysis in patients with pulmonary embolism and signs of shock. In this situation, the treatment must be rapid and effective and assessed on the haemodynamic results in the initial hours. A randomised, multicentre, double-blind clinical trial has clearly shown the superiority of rtPA at the dose of 100 mg given in 2 hours over high dose prolonged urokinase, the fall in total pulmonary resistances being 36 and 18% (p = 0.0009) respectively at the second hour. With respect to the secondary effects, the risk of serious haemorrhage with rtPA does not seem to be less than that of the first generation thrombolytics, and the data of 22 published studies even shows an increased risk of cerebral haemorrhage with rtPA compared with urokinase (1.6 versus 0.5%). Recent experience has shown that bolus administration of rtPA does not improve either the efficacy or safety of this drug. Therefore rtPA (100 mg in 2 hours) is the drug of choice in patients with a low risk of haemorrhage whereas the elderly patients with low body weight and hypertensives should probably be treated with low dose urokinase given in bolus administration, the efficacy/risk ratio of which seems to be satisfactory.

[Infarction in young women caused by intracoronary thrombosis on angiographically normal arteries: apropos of a case]. / Infarctus de la femme jeune par thrombose intracoronaire sur artère angiographiquement normale; à propos d'un cas.

Myocardial infarction is a rare clinical event in young women. The usual presentation is similar to that of older adults. The authors report a case of anteroseptal infarction in a 24 year old woman presenting with paroxysmal epigastric pain without irradiation with fever, during menstruation. The electrocardiogram was compatible with acute pericarditis. The diagnosis was rectified by echocardiography which showed anteroseptal akinesia. Coronary angiography performed as an emergency showed a radiolucent mobile image in the mid segment of the left anterior descending artery with appearances of a distal embolism which were attributed to thrombosis. Intracoronary thrombolysis was associated with a good outcome.

[Contribution of transesophageal echocardiography to the diagnosis of pulmonary embolism]. / Apport de l'échocardiographie transoesophagienne au diagnostic de l'embolie pulmonaire.

Between September 1992 and August 1993 transoesophageal echocardiography was undertaken in 30 patients with clinical and scintigraphic signs of pulmonary embolism. The diagnosis was confirmed by pulmonary angiography (1 patient had failure of venous puncture; 1 patient refused the investigation). The aim of this study was to assess the tolerance and to determine the diagnostic value of transoesophageal echocardiography in patients with suspected pulmonary embolism (PE). Two groups of patients were identified: Group 1: presence of thrombus in the pulmonary artery on transoesophageal echocardiography and group 2: absence of visible thrombus. The produce was well tolerated in all patients. In 21 cases (group 1) 21 thrombi were observed in the right pulmonary artery and 4 thrombi in the left pulmonary artery. The appearances were those of a mobile venous thrombosis in 20 cases (91%) and of clearcut amputation of the proximal segment of the right pulmonary artery in 1 case. No thrombus was detected in 9 patients (group 2). In group 1, the first clinical signs occurred 12 +/- 12 days and the latest signs 2 +/- 3 days before the investigation. One patient had a history of chronic bronchitis. Two patients had a history of PE but with no sign of chronic post-embolic cor pulmonale. Twenty patients underwent pulmonary angiography. Miller's index was 71 +/- 9% and obstruction of proximal pulmonary arteries was observed in 20 patients. In group 2, the PE was confirmed at angiography in 8 cases. The first clinical signs dated from 27 +/- 54 days and the latest signs were observed 6 +/- 4 days before investigation.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of cefadroxil on antigen-induced bronchial hyperresponsiveness and eosinophil accumulation in lung from sensitized guinea pigs.

The effect of a semi-synthetic cephalosporin, Cefadroxil, on antigen-induced bronchial hyperresponsiveness and eosinophil accumulation in lungs from sensitized guinea pigs was investigated and compared to the effects of Cetirizine and Ketotifen. When aerosol-sensitized guinea pigs were pretreated 1 h before the antigen challenge with Cefadroxil (100 mg/kg i.p.) a partial but significant inhibition of the bronchial hyperresponsiveness to aerosolized acetylcholine chloride was observed. Furthermore, the treatment of guinea pigs (115 mg/kg, per os) 24 and 1 h before ovalbumin challenge also significantly reduced bronchial hyperresponsiveness. In contrast, no significant inhibition was noted when the guinea pigs were treated by a single dose of Cefadroxil (115 mg/kg per os) 1 h before challenge. Pretreatment of the guinea pigs with Cetirizine (1 mg/kg per os) or Ketotifen (0.1 mg/kg per os) completely inhibited the antigen-induced bronchial hyperresponsiveness. Cefadroxil (100 mg/kg i.p.) slightly inhibited the accumulation of eosinophils in the peribronchial area induced by antigen challenge. In contrast, no significant reduction was noted when the guinea pigs were treated per os with Cefadroxil (115 mg/kg), Cetirizine (1 or 10 mg/kg) or Ketotifen (0.1 mg/kg). These results show that Cefadroxil is effective in reducing antigen-induced bronchial hyperresponsiveness, an effect independent of a reduction in the pulmonary inflammation, namely eosinophil accumulation in lung.

[Prevalence of atrial arrhythmia in 48 hypertensive patients: research of predictive criteria]. / Etude de la prévalence des troubles du rythme auriculaire chez 48 patients hypertendus: recherche de critères prédictifs.

UNLABELLED: We studied atrial arrhythmias during a continue prospective work in 48 hypertensive patients referred to the OMS criteria. Hypertension was confirmed by a blood pressure ambulatory monitoring and stress testing blood pressure trend. All cardiovascular drugs were stopped at admission. Patients with associated valvular or coronary artery disease were excluded from analysis. In all patients, we realized a twelve lead-ECG, stress testing, 24 hour Holter monitoring, a blood pressure ambulatory monitoring, two-dimensional echocardiography with Doppler study and cardiac radio-nuclide angiography with diastolic function study. Atrial arrhythmias were considered significant if more than 100 premature atrial beats (PAB) and/or more than three successive PAB were present during Holter monitoring. Significant atrial arrhythmias were found in 39.5% of patients (group II, n = 19), not significant in 60.5% of patients (group I, n = 29). The duration of hypertension was longer in group II (140 vs 66 months, p < 0.05). There was no difference between the two populations considering left atrial size or blood pressure level. Furthermore, we were surprised to find a normal E/A ratio on mitral Doppler recording in patients with atrial arrhythmias (1.23 vs 0.9; p < 0.05). Others diastolic parameters didn't significantly differ. Left ventricular mass index was similar in the two groups but patients with atrial arrhythmias had more asymmetric hypertrophy (1.23 vs 1.13 septum/posterior wall ratio: p < 0.05). CONCLUSION: atrial arrhythmias in our study seem to be more dependent from duration of HTA and left ventricular asymmetric structure than from left atrial size.(ABSTRACT TRUNCATED AT 250 WORDS)