Tailored photocleavable peptides: fragmentation and neutralization pathways in high vacuum.

Photocleavable tags (PCTs) have the potential for excellent spatio-temporal control over the release of subunits of complex molecules. Here, we show that electrosprayed oligopeptides, functionalized by a tailored ortho-nitroarylether can undergo site-specific photo-activated cleavage under UV irradiation (266 nm) in high vacuum. The comparison of UV photodissociation (UVPD) and collision-induced dissociation (CID) points to the thermal nature of the cleavage mechanism, a picture corroborated by the temperature dependence of the process. Two competing photodissociation pathways can be identified. In one case a phenolate anion is separated from a neutral zwitterion. In the other case a neutral phenol derivative leaves a negatively charged peptide behind. To understand the factors favoring one channel over the other, we investigate the influence of the peptide length, the nature of the phenolic group and the position of the nitro-group (ortho vs. para). The observed gas phase cleavage of a para-nitro benzylic ether markedly differs from the established behavior in solution.

A transiting giant planet with a temperature between 250 K and 430 K.

Of the over 400 known exoplanets, there are about 70 planets that transit their central star, a situation that permits the derivation of their basic parameters and facilitates investigations of their atmospheres. Some short-period planets, including the first terrestrial exoplanet (CoRoT-7b), have been discovered using a space mission designed to find smaller and more distant planets than can be seen from the ground. Here we report transit observations of CoRoT-9b, which orbits with a period of 95.274 days on a low eccentricity of 0.11 +/- 0.04 around a solar-like star. Its periastron distance of 0.36 astronomical units is by far the largest of all transiting planets, yielding a 'temperate' photospheric temperature estimated to be between 250 and 430 K. Unlike previously known transiting planets, the present size of CoRoT-9b should not have been affected by tidal heat dissipation processes. Indeed, the planet is found to be well described by standard evolution models with an inferred interior composition consistent with that of Jupiter and Saturn.

An orbital period of 0.94 days for the hot-Jupiter planet WASP-18b.

The 'hot Jupiters' that abound in lists of known extrasolar planets are thought to have formed far from their host stars, but migrate inwards through interactions with the proto-planetary disk from which they were born, or by an alternative mechanism such as planet-planet scattering. The hot Jupiters closest to their parent stars, at orbital distances of only approximately 0.02 astronomical units, have strong tidal interactions, and systems such as OGLE-TR-56 have been suggested as tests of tidal dissipation theory. Here we report the discovery of planet WASP-18b with an orbital period of 0.94 days and a mass of ten Jupiter masses (10 M(Jup)), resulting in a tidal interaction an order of magnitude stronger than that of planet OGLE-TR-56b. Under the assumption that the tidal-dissipation parameter Q of the host star is of the order of 10(6), as measured for Solar System bodies and binary stars and as often applied to extrasolar planets, WASP-18b will be spiralling inwards on a timescale less than a thousandth that of the lifetime of its host star. Therefore either WASP-18 is in a rare, exceptionally short-lived state, or the tidal dissipation in this system (and possibly other hot-Jupiter systems) must be much weaker than in the Solar System.

Variable functional recovery and minor cell loss in the ganglion cell layer of the lizard Gallotia galloti after optic nerve axotomy.

The lizard Gallotia galloti shows spontaneous and slow axon regrowth through a permissive glial scar after optic nerve axotomy. Although much of the expression pattern of glial, neuronal and extracellular matrix markers have been analyzed by our group, an estimation of the cell loss in the ganglion cell layer (GCL) and the degree of visual function recovery remained unresolved. Thus, we performed a series of tests indicative of effective visual function (pupillary light reflex, accommodation, visually elicited behavior) in 18 lizards at 3, 6, 9 and 12 months post-axotomy which were then processed for immunohistochemistry for the neuronal markers SMI-31 (neurofilaments), Tuj1 (beta-III tubulin) and SV2 (synaptic vesicles) at the last timepoint. Separately, cell loss in the GCL was estimated by comparative quantitation of DAPI(+) nuclei in control and 12 months experimental lizards. Additionally, 15 lizards were processed for electron microscopy to monitor relevant ultrastructural changes in the GCL, optic nerve and optic tract throughout regeneration. Hypertrophy of RGCs was persistent, morphology of the regenerated nerves varied from narrow to neuroma-like features and larger regenerated axons underwent remyelination by 9 months. The estimated cell loss in the GCL was 27% and two-third of the animals recovered the pupillary light reflex which involves the pretectum. Strikingly, visually elicited behavior involving the tectum was only restored in two specimens, presumably due to the higher complexity of this pathway. These preliminary results indicate that limited functional regeneration occurs spontaneously in the severely injured visual system of the lacertid G. galloti.

Photoinduced work function changes by isomerization of a densely packed azobenzene-based SAM on Au: a joint experimental and theoretical study.

Responsive monolayers are key building blocks for future applications in organic and molecular electronics in particular because they hold potential for tuning the physico-chemical properties of interfaces, including their energetics. Here we study a photochromic SAM based on a conjugated azobenzene derivative and its influence on the gold work function (Φ(Au)) when chemisorbed on its surface. In particular we show that the Φ(Au) can be modulated with external stimuli by controlling the azobenzene trans/cis isomerization process. This phenomenon is characterized experimentally by four different techniques, kelvin probe, kelvin probe force microscopy, electroabsorption spectroscopy and ultraviolet photoelectron spectroscopy. The use of different techniques implies exposing the SAM to different measurement conditions and different preparation methods, which, remarkably, do not alter the observed work function change (Φ(trans)-Φ(cis)). Theoretical calculations provided a complementary insight crucial to attain a deeper knowledge on the origin of the work function photo-modulation.

Long-pulse laser launch and ionization of tailored large neutral silver nanoparticles with atomic mass assignment.

We explore the synthesis, characterization, neutral launch and vacuum ultraviolet ionization of massive perfluorinated-alkyl-capped nanoparticles. The presence of the ligand coating in solution is corroborated by Fourier transform infrared spectroscopy (FT-IR) and the particle size distribution is analyzed by transmission electron microscopy (TEM). Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry identifies perfluoralkyl coated silver nanoparticles as the most stable species among the materials studied here. They can be launched in high vacuum using long-pulse low-power laser heating - orders of magnitude below typical thresholds for laser desorption. Energy-dispersive X-ray spectroscopy (EDX) of the recaptured silver clusters confirms the expected elemental distribution. Volatilization with subsequent ionization of the neutral nanoparticle beam in high vacuum by 157 nm light allows analyzing their mass with atomic resolution.

Tailoring the volatility and stability of oligopeptides.

Amino acids are essential building blocks of life, and fluorinated derivatives have gained interest in chemistry and medicine. Modern mass spectrometry has enabled the study of oligo- and polypeptides as isolated entities in the gas phase, but predominantly as singly or even multiply charged species. While laser desorption of neutral peptides into adiabatically expanding supersonic noble gas jets is possible, UV-VIS spectroscopy, electric or magnetic deflectometry as well as quantum interferometry would profit from the possibility to prepare thermally slow molecular beams. This has typically been precluded by the fragility of the peptide bond and the fact that a peptide would rather 'fry', i.e. denature and fragment than 'fly'. Here, we explore how tailored perfluoroalkyl functionalization can reduce the intermolecular binding and thus increase the volatility of peptides and compare it to previously explored methylation, acylation and amidation of peptides. We show that this strategy is essential and enables the formation of thermal beams of intact neutral tripeptides, whereas only fragments were observed for an extensively fluoroalkyl-decorated nonapeptide. © 2017 The Authors. Journal of Mass Spectrometry Published by John Wiley & Sons Ltd.

Synthesis and characterization of a molecularly imprinted polymer for the determination of spiramycin in sheep milk.

A series of molecularly imprinted polymers (MIPs) comprising reactionary sites which are complementary to macrolide antibiotic spiramycin (SPI) were synthetized by noncovalent bulk polymerization technique. MIPs were synthesized under different polymerization process and their recognition efficiency was evaluated in binding studies in comparison with non-imprinted polymers. The best MIP was morphologically characterized and equilibrium assays were carried out. The MIP was evaluated as a sorbent for extraction and preconcentration of SPI from aqueous and sheep milk samples, and an off-line MISPE method followed by high-performance liquid chromatography with UV diode-array detection was established. Good linearity were obtained for SPI in a range of 24-965µgkg-1 and the average recoveries at three spiked levels in milk samples were higher than 90% (RSD<5%). Limit of quantification was 24.1µgkg-1. Cross-reactivity studies from other macrolides with similar structure were tested. The optimum imprinted polymer showed a good selectivity and affinity for SPI, demonstrating the potential of the proposed MISPE for rapid, sensitive and effective sample pretreatment for selective determination of SPI in sheep milk samples.

Increased salivary oxidative stress parameters in patients with type 2 diabetes: Relation with periodontal disease. / Incremento de los parámetros de estrés oxidativo salival en pacientes con diabetes tipo 2: relación con la enfermedad periodontal.

OBJECTIVE: The aim of this study was to determine whether there are differences in salivary oxidative stress between patients with diabetes mellitus type 2 (DM2) and healthy non-diabetic patients, and whether this oxidative stress is associated with the presence of periodontal disease in diabetic patients. MATERIAL AND METHODS: This observational study included 70 patients divided into three groups according to metabolic control levels: 19 non-diabetic patients (control group); 24 patients with good metabolic control (HbA1c<7%), and 27 patients DM2 with poor metabolic control (HbA1c>7%). The following oxidative stress parameters were measured in all subjects: glutathione peroxidase (GPx), glutathione reductase (GRd), reduced glutathione (GSH) and oxidized glutathione (GSSG). Periodontal health was determined by means of the community periodontal index (CPI) recommended by the WHO. RESULTS: The diabetic group with good metabolic control showed a significant increase in GPx and GRd activity in comparison with the control group (P<.001). The activity of the enzymes measured was significantly less in patients with poor metabolic control in comparison with the control group and well-controlled diabetic groups (P<.001). Both diabetic groups showed higher GSSG/GSH quotients and CPI in comparison with the control group, and both parameters were significantly higher in diabetic patients with poor metabolic control in comparison with well-controlled diabetic patients. CONCLUSIONS: Poor metabolic control in DM2 patients is associated with higher levels of salivary oxidative stress and worse periodontal health.

Liquid chromatography-UV diode-array detection method for multi-residue determination of macrolide antibiotics in sheep's milk.

A rapid, simple and sensitive liquid chromatography-UV diode-array detection method was developed for the simultaneous determination of seven macrolides (erythromycin, oleandomycin, roxithromycin, josamycin, spiramycin, tylosin and ivermectin) in sheep's milk. The column, mobile phase, temperature and flow rate were optimised to provide the best resolution of these analytes. The extraction of the antibiotic residues involves the treatment of protein-free samples with a combination of concentrated sodium hydroxide and ethyl acetate. Necessary defatting is achieved by alkaline hydrolysis. The recovery of each antibiotic was between 55% and 77%, with relative standard deviations ranging from 1% to 6.5%. The limit of quantification was 72.4 microg/kg for ivermectin, 48.3 microg/kg for roxithromycin, and 24.1 microg/kg for erythromycin, oleandomycin, spiramycin, josamycin and tylosin. The procedure was successfully used in the multi-residue determination of these macrolides at levels below the maximum concentrations legally allowed in milk samples.

[Multiple symmetric lipomatosis: a case report]. / Lipomatosis simétrica múltiple: a propósito de un caso.

We present the case of a 46 year-old man with Multiple Symmetric Lipomatosis (MSL), an infrequent disease with an unknown aetiology. MSL is characterized by multiple masses of adipose tissue and it is usually associated with alcoholism, metabolic disorders and neuropathy. We describe the clinical-morphological characteristics of the lesions it presents, the exploratory findings, cervical CAT, the analytical results and the results of subcutaneous biopsy. MSL type I disease was diagnosed. The treatment of choice, the lipectomy, was performed, making it possible to obtain a substantial disease improvement, both physical and aesthetically.

[Frequent users and difficult patients: how do they feel about their treatment by doctors?]. / Pacientes hiperfrecuentadores y difíciles: cómo se sienten tratados por sus médicos?

BACKGROUND: To determine the opinions and expectations of difficult, frequent user, patients about their relationship with their GP. MATERIAL AND METHODS: Qualitative design. Discussion groups. Invitation to a meeting at the Chantrea Health Centre (Pamplona). The participants were frequent users of the health centre in the year 2003, who had been defined as "difficult"--according to previously defined criteria--by each of the 12 doctors of the health centre. Excluded were patients with mental retardation, severe hearing problems, severe mental illness, difficulties in mobility and travelling, and over 70 years of age. Groups were formed from amongst the 112 preselected patients. Four groups were designed: "older" persons (GMA) of 46 to 70 years (14); "women" (GMU) of 31 to 45 years (14); "men" (GHO) of 31 to 45 years (13) and "youths" (GJO) of 16 to 30 years (12). The patients were invited by letter and by a subsequent telephone confirmation to a meeting, the content of which was not specified. Sessions of 2 hours duration were held with each of the groups formed. Audio recording, with prior authorization, and verbatim transcription of sessions. Discussion and content analysis by the research group resulting in lines of consensus. RESULTS: The three groups of older patients were formed with a total of 16 participants. The group of youths was not formed since the figure for attendance did not reach the number of 3 or more after three appointments. CONCLUSIONS: From the perspective of the patient it is very important that there should be efficient communication with the doctor. Awareness of a state of frequent use was not detected in those attending. They feel themselves to be chronic patients who need frequent attention. Satisfaction at the treatment received was observed as well as an understanding attitude towards the organisational limitations of the health centre. They did not give verbal expression to the existence of conflictive relations with their GPs.

Identification of the current path for a conductive molecular wire on a tripodal platform.

We present the chemical synthesis as well as charge transport measurements and calculations for a new tripodal platform based on a rigid 9,9'-spirobifluorene equipped with a phenylene-ethynylene wire. The transport experiments are performed with the help of the low-temperature mechanically controlled break junction technique with gold electrodes. By combining experimental and theoretical investigations of elastic and inelastic charge transport, we show that the current proceeds through the designated molecular wire and identify a binding geometry that is compatible with the experimental observations. The conductive molecular wire on the platform features a well-defined and relatively high conductance of the order of 10(-3)G0 despite the length of the current path of more than 1.7 nm, demonstrating that this platform is suitable to incorporate functional units like molecular switches or sensors.

Acute and long-term beta-adrenergic blockade for patients with neurocardiogenic syncope.

OBJECTIVES: This study was designed to prospectively evaluate the long-term outcome of drug therapy guided by head-up tilt testing for the management of unexplained syncope and near syncope. BACKGROUND: Head-up tilt testing is used to evaluate patients with unexplained syncope. The validity of acute drug testing and the efficacy of long-term oral therapy for prevention of recurrent syncope have not been investigated in large patient groups. METHODS: We studied 296 consecutive patients with unexplained syncope or near syncope who underwent 80 degrees head-up tilt testing with and without isoproterenol challenge. The efficacy of intravenous and oral beta-blocker therapy was evaluated by repeat testing. Patients with both positive and negative responses to therapy were followed up for rates of recurrence of syncope. RESULTS: A total of 193 patients (65%) had a positive tilt test response; 89% of these 193 required isoproterenol challenge to elicit this response. Patients with a positive tilt test result had lower values for heart rate at rest (mean +/- SD 69 +/- 13 vs. 74 +/- 14 beats/min, p = 0.046) and systolic blood pressure (137 +/- 28 vs. 145 +/- 30 mm Hg, p = 0.0018) at baseline than did the patients with a negative tilt test result. Intravenous propranolol blocked the positive response in 163 (90%) of 181 patients retested. Oral beta-blockers were effective by tilt test criteria in 118 (94%) of 125 patients; 12 (10%) had recurrent clinical symptoms while taking beta-blockers. Eight (42%) of 19 patients who had a negative tilt test response during beta-blocker therapy had recurrent symptoms when they stopped therapy. Three (23%) of 13 patients receiving empiric beta-blocker therapy had recurrent symptoms. The follow-up period for the patients with a positive tilt test result was 28 +/- 11 months (range 5 to 48). CONCLUSIONS: Intravenous propranolol is effective in preventing neurocardiogenic syncope diagnosed during head-up tilt testing and predicts the response to oral beta-blocker therapy. Oral beta-blocker therapy prevents recurrent syncope in the majority of patients. Recurrence of syncope is lowest when efficacy of oral beta-blocker therapy is confirmed by repeat head-up tilt testing.

Hipomineralización en dentición temporal: ¿factor predictivo de him? / No disponible

La terminología hipomineralización incisivo-molar (HIM) fue descrita por primera vez en 2001 para explicar los defectos de desarrollo cualitativos demarcados del esmalte, que afectan a uno o más molares permanentes, con o sin participación de los incisivos per-manentes1. En los últimos años, las investigaciones han dado lugar a informes de lesiones comparables en segundos molares temporales hipomineralizados, sin embargo, se desconoce si la presencia de opacidades demarcadas en los caninos temporales también puede asociarse con el HIM1-3. Da Silva y cols., en 2017, son los únicos autores hasta el momento que relacionan hipomineralizaciones en segundos molares temporales (HSPM) y caninos temporales (HPC)3. La prevalencia de HSPM varía dependiendo de los países entre 2,9% a un 21,8% 3,7.Se puede esperar que las causas de los defectos de hipomineralización en los segundos molares temporales sean las mismas que en los dientes permanentes, si ocurren conco-mitantemente a la calcificación de su corona, la cual comienza alrededor de la decimooctava semana de gestación 4-7. Se presenta el caso de un paciente infantil, de 6 años, que acudió a consulta para revisión odontológica. Tras la exploración, se observó la presencia de anomalías del color y estructura en: todos los segundos molares y caninos temporales, así como en los primeros molares temporales superiores y primer molar temporal inferior izquierdo (Figuras 1-6). La posterior exploración radiográfica mostró hallazgos patológicos localizados en 54, 64, 65, 74, 75, 84, 85 (Figuras 7-9). El tratamiento supone un desafío ya que es frecuente que los dientes afectados presenten afectación pulpar, además de hipersensibilidad y descomposición post*eruptiva. Esta relación podría sugerir como factor predictivo de aparición de HIM, la presencia HSPM y HPC, así podrían implementarse las medidas de prevención y control con intervalos más frecuentes en estos pacientes

No disponible

Occurrence of erythromycin residues in sheep milk. Validation of an analytical method.

The paper describes a new and selective analytical sample treatment for quantitative extraction and preconcentration of erythromycin in presence of other macrolide antibiotics in sheep milk samples. The methodology is based on the use of a molecular imprinted polymer (MIP) employed as solid phase extraction sorbent (MISPE). The synthesized material by bulk polymerization using erythromycin (ERY) as template was evaluated as solid phase extraction sorbent, in a novel sample treatment technique that can be coupled to high-performance liquid chromatography with diode-array detector (HPLC-DAD). MIP selectivity was studied for other macrolide antibiotics with similar structures, such as tylosin (TYL), spiramycin (SPI), josamycin (JOS), roxithromycin (ROX) and ivermectin (IVER) getting recoveries for these interferents lower than 35%, for all cases except for ROX, which recoveries were around 85%. The variables affecting the molecularly imprinted solid-phase extraction (MISPE) procedure were optimized to select the best conditions of selectivity and sensitivity to determine ERY at concentration levels established by EU legislation in sheep milk. Under the selected experimental conditions, quantification limit was 24.1 µg kg(-1). Recoveries were higher than 98%, with RSDs between 0.7% and 2%. The proposed MISPE-HPLC method was validated and successfully applied to ERY analysis in sheep milk samples.

Radial glia and astrocytes in developing and adult telencephalon of the lizard Gallotia galloti as revealed by immunohistochemistry with anti-GFAP and anti-vimentin antibodies.

The development of radial glia and astrocytes in the telencephalon of the lizard Gallotia galloti was studied by immunohistochemistry with anti-vimentin and anti-GFAP antibodies. Vimentin appears at embryonic stage 32 (E32) in the proliferative zone of the lateral ventricle and subpial end-feet in the marginal zone. At E34-35 the staining intensity for vimentin in all radial glia is maximal. It then decreases and disappears in most structures in adult animals. GFAP appears at E35 in the end-feet in the marginal zone and its intensity increases until adulthood, particularly in radial and sinuous fibers and in fibers that originate from the sulci and invade the ventral striatum and the septum. In contrast, the reaction is weak in the cortex, in the anterior dorso-ventricular ridge, and in the amygdala nuclei. Radial glia is still present in the adult, and the composition of its intermediate filaments changes during development from vimentin to GFAP. No GFA-positive cell bodies except those of ependymal glia were detected in telencephalon.

Glial fibrillary acidic protein and vimentin immunohistochemistry in the developing and adult midbrain of the lizard Gallotia galloti.

The distribution of glial fibrillary acidic protein (GFAP)- and vimentin-containing cells was studied by immunohistochemistry in the midbrain of the lizard Gallotia galloti. At embryonic stage 32 (E32), vimentin immunoreactivity appeared first in cell bodies located in the ventricular walls, in radial fibers, and subpial end-feet and increased in these structures until E34/E35. Faint GFAP immunoreactivity gradually appeared in the same structures between E34 and E37, and this increased until adulthood, whereas vimentin immunoreactivity decreased after E35, becoming limited to a few end-feet and fibers in the adult, mainly in the tegmentum. Thus, in developing Gallotia midbrain a shift from vimentin-containing to GFAP-containing intermediate filaments begins around E36 or E37. At E40, in addition to the cell bodies in the ependymal area, dispersed GFAP-positive cells, possibly immature astrocytes appeared. These cells showed the same shift. In the adult lizard, GFAP-positive radial glia are still present and coexist with GFAP-positive astrocytes, which are prefentially located in the marginal optic tract and the oculomotor nuclei, but are absent in the fasciculus longitudinalis medialis. Optic tectum, pretectum, tegmentum, and isthmic nuclei are the areas richest in GFAP-positive radial fibers: these were much less abundant in the deep mesencephalic nuclei. Thus, in this lizard, GFAP-positive astrocytes display a clear cut regional distribution: they are present in mesencephalon, whereas they are absent in telencephalon.

Abnormal left ventricular diastolic filling in eccentric left ventricular hypertrophy of obesity.

Left ventricular (LV) diastolic filling pattern of obese subjects with eccentric LV hypertrophy was studied. Findings were compared with those of normal control subjects and hypertensive patients with concentric LV hypertrophy. M-mode, 2-dimensional and Doppler echocardiograms were recorded in 11 obese (body mass index greater than 30 kg/m2) normotensive patients with eccentric LV hypertrophy, 10 normal control subjects, and 18 nonobese, hypertensive patients with concentric LV hypertrophy whose antihypertensive medications were discontinued 2 weeks before study. LV hypertrophy was defined as LV mass/height greater than 143 g/m. Hypertrophy in the obese patients was eccentric: Their LV internal dimension (61 +/- 3 mm) was greater than that of hypertensive patients (55 +/- 5 mm, p less than 0.001) and normal control subjects (55 +/- 2 mm, p less than 0.01); their septal (10.7 +/- 0.7 mm) and posterior (10.9 +/- 0.6 mm) wall thicknesses were smaller than those of the hypertensive patients (12.2 +/- 1.7 mm, p less than 0.05 and 11.7 +/- 1.2 mm, respectively, difference not significant). Pulsed-wave Doppler echocardiographic filling indexes were used to evaluate LV diastolic filling. Obese patients had a higher peak velocity of atrial filling (69 +/- 14 vs 54 +/- 15 cm/s, p less than 0.05), lower early/atrial filling velocity ratio (1.0 +/- 0.26 vs 1.32 +/- 0.21, p less than 0.05), prolonged deceleration half-time (108 +/- 9 vs 86 +/- 15 ms, p less than 0.01) and lower peak filling rate corrected to stroke volume (4.08 +/- 0.68 vs 4.96 +/- 0.88 stroke volume/s, p less than 0.05) than normal control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)