Is the largest aqueous gold cluster a superatom complex? Electronic structure & optical response of the structurally determined Au146(p-MBA)57.

The new water-soluble gold cluster Au146(p-MBA)57, the structure of which has been recently determined at sub-atomic resolution by Vergara et al., is the largest aqueous gold cluster ever structurally determined and likewise the smallest cluster with a stacking fault. The core presents a twinned truncated octahedron, while additional peripheral gold atoms follow a C2 rotational symmetry. According to the usual counting rules of the superatom complex (SAC) model, the compound attains a number of 92 SAC electrons if the overall net charge is 3- (three additional electrons). As this is the number of electrons required for a major shell closing, the question arises of whether Au146(p-MBA)57 should be regarded as a superatom complex. Starting from the experimental coordinates we have analyzed the structure using density-functional theory. The optimized (relaxed) structure retains all the connectivity of the experimental coordinates, while removing much of its irregularities in interatomic distances, thereby enhancing the C2-symmetry feature. On analyzing the angular-momentum-projected states, we show that, despite a small gap, the electronic structure does not exhibit SAC model character. In addition, optical absorption spectra are found to be relatively smooth compared to the example of the Au144(SR)60 cluster. The Au146(SR)57 does not derive its stability from SAC character; it cannot be considered as a superatom complex.

Transmission electron microscopy as a tool for nanocrystal characterization pre- and post-injector.

Recent advancements at the Linac Coherent Light Source X-ray free-electron laser (XFEL) enabling successful serial femtosecond diffraction experiments using nanometre-sized crystals (NCs) have opened up the possibility of X-ray structure determination of proteins that produce only submicrometre crystals such as many membrane proteins. Careful crystal pre-characterization including compatibility testing of the sample delivery method is essential to ensure efficient use of the limited beamtime available at XFEL sources. This work demonstrates the utility of transmission electron microscopy for detecting and evaluating NCs within the carrier solutions of liquid injectors. The diffraction quality of these crystals may be assessed by examining the crystal lattice and by calculating the fast Fourier transform of the image. Injector reservoir solutions, as well as solutions collected post-injection, were evaluated for three types of protein NCs (i) the membrane protein PTHR1, (ii) the multi-protein complex Pol II-GFP and (iii) the soluble protein lysozyme. Our results indicate that the concentration and diffraction quality of NCs, particularly those with high solvent content and sensitivity to mechanical manipulation may be affected by the delivery process.

Pseudoquiste de páncreas con extensión a mediastino / Pancreatic pseudocyst extended to the mediastinum: case report

We report a 53 years old male consulting for chest pain and dyspnea. On physical examination, an epigastric mass was detected. A TC scan showed a collection located in the omental bursa, which protruded over the posterior gastric wall and ascended to the mediastinum. Due to the presence of pancreatic calcifications, a pancreatic pseudocyst was suspected. The mediastinal cyst was drained percutaneously, leaving pig tail drainage in the cavity. Afterwards a cyst excision and Roux en Y gastrostomy was performed. After the surgical procedure the cyst became infected, requiring antimicrobials. After two weeks he was discharged in good conditions.

Los pseudoquistes de páncreas representan el 75 por ciento de las lesiones quísticas del páncreas y generalmente se circunscriben en el abdomen. Se presenta el caso de un paciente con un pseudoquiste de páncreas con extensión transhiatal a mediastino. Estos casos deben sospecharse mediante una historia clínica detallada y preguntando por antecedentes de dolor abdominal previo porque la clínica con la que se suelen manifestar es muy poco específica. El tratamiento de los pseudoquistes con extensión a mediastino debería ser el drenaje definitivo, bien de forma quirúrgica o endoscópica.

Hábito tabáquico en pacientes con enfermedad pulmonar obstructiva crónica. Estudio EPOTABAC / Smoking among patients with chronic obstructive pulmonary disease. The EPOTABAC study

Objetivos: Determinar la prevalencia del hábito tabáquico en pacientes con EPOC y describir los métodos utilizados para la deshabituación tabáquica. Pacientes y métodos: Estudio observacional, transversal y multicéntrico en pacientes con EPOC mayores de 40 años desarrollado en el ámbito de la Atención Primaria (AP). Resultados: Participaron 202 médicos que incluyeron 685 pacientes valorables (edad media 66,1 años (DE=10,4); 86,4% hombres). Un 34,3% de los pacientes fumaba en el momento del estudio. Se realizó la espirometría en el momento de la inclusión en 242 pacientes y se dispuso del valor de FEV1% en 190. La gravedad de la enfermedad se clasificó en 39,5% leve, 41,1% moderada y 19,5% grave. La evolución media de la enfermedad fue de 10,5 años (DE=7,3), con una media de agudizaciones al año de 2,2 (DE=1,8). En la mayoría de los casos (64,1%) fue el médico quien aconsejó dejar de fumar. El 27,3% de los pacientes utilizó terapias sustitutivas de nicotina, el 16,1% utilizó tratamientos farmacológicos no nicotínicos y el 17,4% terapias no farmacológicas. Conclusiones: Más de un tercio de los pacientes con EPOC diagnosticados mediante función pulmonar continuaba fumando. Se destaca la necesidad de implementar y mantener programas de deshabituación de tabaco en AP (AU)

Introduction: The aim of this study was to determine the prevalence of tobacco use among COPD patients and to describe the methods used by patients to stop smoking. Patients and methods: A multicenter, observational, cross-sectional study at primary care level involving patients with COPD over 40 years of age. Results: 685 evaluable patients [mean age 66.1 (SD= 10.4); 86.4% were men) were recruited for the study by 202 general physicians. 34.3% were current smokers at the time of the study. Spirometry was performed at the inclusión in 242 patients, FEV1% value was available for 190 patients. COPD severity was classified as follows: mild in 39.5%, moderate in 41.1% and severe in 19.5%. Mean disease duration was 10.5 years (SD= 7.3) and the mean number of exacerbations per year was 2.2 (SD=1.8). 27.3% of the patients used nicotine replacement therapy, 16.1% used non-nicotine pharmacological treatments and 17.4% used non pharmacological therapies. Conclusions: More than one third of COPD patients diagnosed through pulmonary function testing continued to smoke. The need to implement and support smoking cessation programs in primary healthcare is emphasised (AU)

The statistical mechanics of complex signaling networks: nerve growth factor signaling.

The inherent complexity of cellular signaling networks and their importance to a wide range of cellular functions necessitates the development of modeling methods that can be applied toward making predictions and highlighting the appropriate experiments to test our understanding of how these systems are designed and function. We use methods of statistical mechanics to extract useful predictions for complex cellular signaling networks. A key difficulty with signaling models is that, while significant effort is being made to experimentally measure the rate constants for individual steps in these networks, many of the parameters required to describe their behavior remain unknown or at best represent estimates. To establish the usefulness of our approach, we have applied our methods toward modeling the nerve growth factor (NGF)-induced differentiation of neuronal cells. In particular, we study the actions of NGF and mitogenic epidermal growth factor (EGF) in rat pheochromocytoma (PC12) cells. Through a network of intermediate signaling proteins, each of these growth factors stimulates extracellular regulated kinase (Erk) phosphorylation with distinct dynamical profiles. Using our modeling approach, we are able to predict the influence of specific signaling modules in determining the integrated cellular response to the two growth factors. Our methods also raise some interesting insights into the design and possible evolution of cellular systems, highlighting an inherent property of these systems that we call 'sloppiness.'

Paracoccidioidomycosis (South American blastomycosis) successfully treated with terbinafine: first case report.

We describe a 63-year-old man who presented with painful malodorous lesions in the perianal, perineal and scrotal regions. Following definitive diagnosis of paracoccidioidomycosis, he was treated initially with trimethoprim/sulphamethoxazole, but there was no clinical improvement. He then received terbinafine (Lamisil) 250 mg twice daily for 6 months. There was rapid resolution of all lesions and complete relief of symptoms, without any associated side-effects. The patient remains clinically well and without any evidence of infection 2 years after discontinuation of terbinafine treatment.

Maleic acid and succinic acid in fermented alcoholic beverages are the stimulants of gastric acid secretion.

Alcoholic beverages produced by fermentation (e.g., beer and wine) are powerful stimulants of gastric acid output and gastrin release in humans. The aim of this study was to separate and specify the gastric acid stimulatory ingredients in alcoholic beverages produced by fermentation. Yeast-fermented glucose was used as a simple model of fermented alcoholic beverages; it was stepwise separated by different methods of liquid chromatography, and each separated solution was tested in human volunteers for its stimulatory action on gastric acid output and gastrin release. Five substances were detected by high-performance liquid chromatography and were analyzed by mass spectrometry and 1H-13C nuclear magnetic resonance spectroscopy. At the end of the separation process of the five identified substances, only the two dicarboxylic acids, maleic acid and succinic acid, had a significant (P < 0.05) stimulatory action on gastric acid output (76% and 70% of fermented glucose, respectively), but not on gastrin release. When given together, they increased gastric acid output by 100% of fermented glucose and by 95% of maximal acid output. We therefore conclude that maleic acid and succinic acid are the powerful stimulants of gastric acid output in fermented glucose and alcoholic beverages produced by fermentation, and that gastrin is not their mediator of action.

A 17mer peptide interferes with acidification-induced uncoupling of connexin43.

Structure/function analysis shows that the carboxyl terminal (CT) domain of connexin43 (Cx43) is essential for the chemical regulation of cell-cell communication. Of particular interest is the region between amino acids 260 and 300. Structural preservation of this region is essential for acidification-induced uncoupling (ie, pH gating). In this study, we report data showing that a 17mer peptide of the same sequence as amino acids 271 to 287 of Cx43 (CSSPTAPLSPMSPPGYK) can prevent pH gating of Cx43-expressing oocytes. Experiments were carried out in pairs of Xenopus oocytes previously injected with connexin38 antisense and expressing wild-type Cx43. Junctional conductance was measured electrophysiologically. pHi was determined from the light emission of the proton-sensitive dye dextran-seminaphthorhodafluor. Intracellular acidification was induced by superfusion with a bicarbonate-buffered solution gassed with a progressively increasing concentration of CO2. Injection of water alone into both oocytes of a Cx43-expressing pair or injection of a peptide from region 321 to 337 of Cx43 did not modify pH sensitivity. However, injection of a polypeptide corresponding to amino acids 241 to 382 of Cx43 interfered with the ability of gap junctions to close on acidification. Similar results were obtained when a 17mer peptide (region 271 to 287) was injected into both oocytes of the pair. Normal Cx43 pH gating was observed if (1) the amino acid sequence of the 17mer peptide was scrambled or (2) the N and the C ends of the 17mer peptide were not included in the sequence. This is the first demonstration of a molecule that can interfere with the chemical regulation of connexin channels in a cell pair. The data may lead to the development of small molecules that can be used in Cx43-expressing multicellular preparations to study the role of gap junction regulation in normal as well as diseased states.

Alcoholic beverages produced by alcoholic fermentation but not by distillation are powerful stimulants of gastric acid secretion in humans.

BACKGROUND: The effect of commonly ingested alcoholic beverages on gastric acid output and release of gastrin in humans is unknown. AIM AND METHODS: In 16 healthy humans the effect of some commonly ingested alcoholic beverages produced by fermentation plus distillation (for example, whisky, cognac, calvados, armagnac, and rum) or by alcoholic fermentation (beer, wine, champagne, martini, and sherry) on gastric acid output and release of gastrin was studied. Gastric acid output was determined by the method of intragastric titration. Plasma gastrin was measured using a specific radioimmunoassay. RESULTS: None of the alcoholic beverages produced by fermentation plus distillation had any significant effect on gastric acid output and release of gastrin compared with control (isotonic glucose and distilled water). Alcoholic beverages produced only by fermentation significantly (p < 0.05) increased the gastric acid output by 57% to 95% of maximal acid output (MAO) and release of gastrin up to 5.1-fold compared with control. If beer, wine, and sherry were distilled, only their remaining parts increased gastric acid output by 53% to 76% of MAO and increased release of gastrin up to 4.3-fold compared with control. CONCLUSIONS: (1) Alcoholic beverages produced by fermentation but not by distillation are powerful stimulants of gastric acid output and release of gastrin; (2) the alcoholic beverage constituents that stimulate gastric acid output and release of gastrin are most probably produced during the process of fermentation and removed during the following process of distillation.

Action of ethanol and some alcoholic beverages on gastric acid secretion in anaesthetized rats.

The action of intragastric ethanol in various concentrations equivalent to those found in alcoholic beverages (1.5-40 v/v), ethanol 96% (v/v) and of some commonly ingested alcoholic beverages produced by alcoholic fermentation (beer, wine, champagne, martini and sherry) or by fermentation plus distillation (e.g. whisky, cognac, calvados, armagnac and rum) on gastric acid output (GAO) was studied in anaesthetized Wistar rats. Ethanol concentrations of 1.5%, 4% and 10% v/v did not significantly alter basal GAO, whereas all higher concentrations of ethanol (20%, 40% and 96% v/v) significantly (P < 0.05) and dose-dependently decreased the GAO. All alcoholic beverages produced by fermentation significantly increased GAO by 30-35% of maximal acid output (MAO; 48 micrograms/kg pentagastrin intramuscularly), whereas alcoholic beverages produced by fermentation plus distillation significantly decreased GAO as compared to control (isotonic glucose and distilled water). Glucose solutions to which yeast was added, resulting in fermentation, were as potent stimuli of GAO as beer. Lyophilized fermented glucose at different concentrations (dilution of 1:20 to 1:1) dose-dependently stimulated GAO: the highest dilution (1:20) had no effect, the 1:5 dilution significantly increased gastric acid secretion similarly to that of beer and fermented glucose. The highest concentration of lyophilized fermented glucose (1:1) was as potent as the MAO after pentagastrin (90% of MAO). In conclusion, the present investigation shows for the first time that, in rats: (1) ethanol in a concentration > 10% v/v inhibits GAO; (2) lower ethanol concentrations (< 10% v/v) do not alter GAO; (3) alcoholic beverages produced by fermentation but not those produced by alcoholic fermentation plus distillation are powerful stimulants of GAO; (4) the stimulatory non-alcoholic ingredients of these alcoholic beverages are most likely produced during the process of fermentation of carbohydrates and removed during the following process of distillation.

PH regulation of connexin43: molecular analysis of the gating particle.

Gap junction channels allow for the passage of ions and small molecules between neighboring cells. These channels are formed by multimers of an integral membrane protein named connexin. In the heart and other tissues, the most abundant connexin is a 43-kDa, 382-amino acid protein termed connexin43 (Cx43). A characteristic property of connexin channels is that they close upon acidification of the intracellular space. Previous studies have shown that truncation of the carboxyl terminal of Cx43 impairs pH sensitivity. In the present study, we have used a combination of optical, electrophysiological, and molecular biological techniques and the oocyte expression system to further localize the regions of the carboxyl terminal that are involved in pH regulation of Cx43 channels. Our results show that regions 261-300 and 374-382 are essential components of a pH-dependent "gating particle," which is responsible for acidification-induced uncoupling of Cx43-expressing cells. Regions 261-300 and 374-382 seem to be interdependent. The function of region 261-300 may be related to the presence of a poly-proline repeat between amino acids 274 and 285. Furthermore, site-directed mutagenesis studies show that the function of region 374-382 is not directly related to its net balance of charges, although mutation of only one amino acid (aspartate 379) for asparagine impairs pH sensitivity to the same extent as truncation of the carboxyl terminal domain (from amino acid 257). The mutation in which serine 364 is substituted for proline, which has been associated with some cases of cardiac congenital malformations in humans, also disrupts the pH gating of Cx43, although deletion of amino acids 364-373 has no effect on acidification-induced uncoupling. These results provide new insight into the molecular mechanisms responsible for acidification-induced uncoupling of gap junction channels in the heart and in other Cx43-expressing structures.

Desensitization and internalization of adenosine A1 receptors in rat brain by in vivo treatment with R-PIA: involvement of coated vesicles.

Chronic treatment of rats with R-PIA 'in vivo' desensitized adenosine A1 receptor-mediated inhibition of adenylyl cyclase in brain plasma membranes and increased basal and forskolin-stimulated adenylyl cyclase. The adenosine A1 receptor agonist CHA (cyclohexyl adenosine) inhibited forskolin-stimulated adenylyl cyclase in synaptic plasma membranes from control rats but failed to do so in membranes isolated from rats treated with R-PIA. This loss of response was accompanied with a significant decrease in both, total number of adenosine A1 receptors and steady-state level of alpha-Gi in synaptic plasma membranes. An increase in the steady-state level of alpha-Gs in synaptic plasma membranes was also observed by R-PIA treatment. Concurrently, a significant increase of adenosine A1 receptors was observed in microsomes and coated vesicles. These results demonstrate adenosine A1 receptor desensitization in rat brain by 'in vivo' treatment with R-PIA and suggest a role for coated vesicles in the internalization of G-protein coupled receptors.

G-protein-coupled A1 adenosine receptors in coated vesicles of mammalian brain: characterization by radioligand binding and photoaffinity labelling.

A1 adenosine receptors in coated vesicles have been characterized by radioligand binding and photoaffinity labelling. Saturation experiments with the antagonist 8-cyclopentyl-1,3-[3H]dipropyl-xanthine ([3H]DPCPX) gave a Kd value of 0.7 nM and a Bmax value of 82 +/- 13 fmol/mg protein. For the highly A1-selective agonist 2-chloro-N6-[3H]cyclopentyladenosine ([3H]CCPA) a Kd value of 1.7 nM and a Bmax value of 72 +/- 29 fmol/mg protein was estimated. Competition of agonists for [3H]DPCPX binding gave a pharmacological profile with R-N6-phenylisopropyladenosine (R-PIA) > CCPA > S-PIA > 5'-N-ethylcarboxamidoadenosine (NECA), which is identical to brain membranes. The competition curves were best fitted according to a two-site model, suggesting the existence of two affinity states. GTP shifted the competition curve for CCPA to the right and only one affinity state similar to the low affinity state in the absence of GTP was detected. The photoreactive agonist 2-azido-N6-125I-p-hydroxyphenylisopropyladenosine ([125I]AHPIA) specifically labelled a single protein with an apparent molecular weight of 35,000 in coated vesicles, which is identical to A1 receptors labelled in brain membranes. Therefore, coated vesicles contain A1 adenosine receptors with similar binding characteristics as membrane-bound receptors, including GTP-sensitive high-affinity agonist binding. Photoaffinity labelling data suggest that A1 receptors in these vesicles are not a processed receptor form. These results confirm that A1 receptors in coated vesicles are coupled to a G-protein, and it appears that the A1 receptor systems in coated vesicles and in plasma membranes are identical.

Presence of phospholipase C in coated vesicles from bovine brain. Dual regulatory effects of GTP-analogs.

Bovine brain coated vesicles display free calcium-dependent phospholipase C activity. Gpp(NH)p and GTP gamma S inhibited phospholipase C at nanomolar concentrations. Increasing concentrations of Gpp(NH)p and GTP gamma S reversed the inhibitory effects and stimulated phospholipase C activity. Preincubation of coated vesicles with pertussis toxin blocked the poorly-hydrolyzable GTP-analogs' inhibitory effects on phospholipase C. These data indicate that guanine nucleotides exert a dual regulatory control of phospholipase C in coated vesicles and that the inhibitory pathway is mediated by a pertussis toxin-sensitive G-protein.

Characterization of L-[3H]glutamate binding sites in bovine brain coated vesicles.

Clathrin-coated vesicles isolated from bovine brain exhibit an L-[3H]glutamate-specific binding. Coated vesicles were purified from bovine brain by differential centrifugation and gel filtration. High purity of coated vesicles was established previously by several enzyme markers and electron microscopy. The binding activity was performed in the absence of Na+, Ca2+, and Cl- ions to avoid binding and/or uptake to uptake sites. Coated vesicles were frozen, thawed, treated with 0.04% Triton X-100 and washed before incubation with L-[3H]glutamate. Saturation binding experiments revealed a single binding site with a Kd = 439 +/- 87 nM and a Bmax = 11.74 +/- 3.4 pmol/mg protein, consistent with kinetics characteristic for glutamate receptors. The glutamate-specific binding was stereospecific for glutamate and aspartate, showing higher affinity for L-forms than D-forms. Pharmacological characterization indicated that specific binding was sensitive to quisqualate and almost insensitive to kainate and N-methyl-D-aspartate. 200 microM guanosine triphosphate (GTP) produced a decrease of 50% in L-[3H]glutamate binding activity and competition experiments produced an affinity shift to the right of the glutamate dose-response curve. These results support the evidence that glutamate receptors are present in bovine brain coated vesicles and, at least in part, are associated to a G-protein.

Coupling of adenosine A1 receptors to a G-protein in coated vesicles isolated from bovine brain: presence of pertussis and cholera toxin substrates.

Adenosine A1 receptors have been described in coated vesicles isolated from bovine brain (Gonzalez-Calero et al., J. Neurochem. 1990, 55, 106-113). Addition of non hydrolyzable GTP analogue (guanyl-5-yl-imidodiphosphate) caused a transition of the receptor from the high- to the low-affinity state, without any significant change in the total binding sites. The presence of G-proteins has been investigated by pertussis and cholera toxins catalyzed ADP-ribosylation. A band of Mr = 41,000 D, similar to the alpha Gi subunit, was specifically labeled in the presence of preactivated pertussis toxin. Bands of Mr = 42,000 D and Mr = 47,000 D were specifically labeled in the presence of preactivated cholera toxin. These results confirm the presence of GTP binding proteins (alpha Gi and alpha Gs) in coated vesicles isolated from bovine brain.

Bovine brain coated vesicles contain adenosine A1 receptors. Presence of adenylate cyclase coupled to the receptor.

Clathrin-coated vesicles purified from bovine brain express adenosine A1 receptor binding activity. N6-Cyclohexyl[3H]adenosine [( 3H]CHA), an agonist for the A1 receptor, binds specifically to coated vesicles. High and low agonist affinity states of the receptor for the radioligand [3H]CHA with KD values of 0.18 and 4.4 nM, respectively, were detected. The high purity of coated vesicles was established by assays for biochemical markers and by electron microscopy. Binding competition experiments using agonists (N6CHA, N-cyclopentyladenosine, 5'-(N-ethylcarboxamido)adenosine, and N6-[(R)- and N6-[(S)-phenylisopropyl]adenosine) and antagonists (theophylline, 3-isobutyl-1-methylxanthine, and caffeine) confirmed the typical adenosine A1 nature of the binding site. This binding site presents stereospecificity for N6-phenylisopropyladenosine, showing 33 times more affinity for N6-[(R)- than for N6-[(S)-phenylisopropyl]adenosine. The specific binding of [3H]CHA in coated vesicles is regulated by guanine nucleotides. [3H]CHA specific binding was decreased by 70% in the presence of the hydrolysis-resistant GTP analogue guanyl-5-yl-imidodiphosphate. Bovine brain coated vesicles present adenylate cyclase activity. This activity was modulated by forskolin and CHA. The results of this study support the evidence that adenosine A1 receptors present in coated vesicles are coupled to adenylate cyclase activity through a Gi protein.

[Illig-Fanconi disease. First case described in Ecuador]. / Enfermedad de Illig-Fanconi. Primer caso descrito en Ecuador.

We are presenting here one case of Illig-Fanconi disease, in one month old baby otherwise in good health. The clinical evolution was characterized by flares of lesions every fifteen days more or less; these lesions were papules of one to two centimeters of diameter, some of them having a central depression, and leaving a white patches when they cleared up. The disease disappeared completely when the child was six months old, and there were not any recurrence until today. No systemic involvement was detected.