Recurrent cerebellar ischemic infarctions and stereotyped peri-ictal sympathetic responses in a near-SUDEP patient with cardiovascular risk factors.

We report a 60-year-old woman who presented to the emergency department after experiencing a witnessed unknown onset bilateral tonic clonic seizure (GTCS) that culminated in cardiac arrest. A neurology consultant uncovered a years-long history of frequent episodic staring followed by confusion and expressive aphasia, which strongly suggested that she suffered from epilepsy. Thus, her cardiac arrest and subsequent resuscitation met criteria for a near-sudden unexpected death in epilepsy (SUDEP) diagnosis. Serial bloodwork demonstrated transient troponin I elevations and leukocytoses, while a brain MRI revealed global cerebral anoxic injury and a small acute right cerebellar ischemic infarction. A review of her medical record uncovered a hospitalization sixteen months earlier for a likely GTCS whose workup showed similar troponin I elevations and leukocytoses, and surprisingly, a different small acute right cerebellar ischemic infarction in the same vascular territory. To our knowledge, this is the first report of subcortical ischemic infarctions occurring concurrently with GTCSs in a near-SUDEP patient. Aside from illustrating the key role of inpatient neurologists in the diagnosis of near-SUDEP, this manuscript discusses the potential significance of postictal ischemic infarctions, transient asymptomatic troponin elevations, and transient non-infectious leukocytoses in epilepsy patients with cardiovascular risk factors.

Ib-M6 Antimicrobial Peptide: Antibacterial Activity against Clinical Isolates of Escherichia coli and Molecular Docking.

The Ib-M6 peptide has antibacterial activity against non-pathogenic Escherichia coli K-12 strain. The first part of this study determines the antibacterial activity of Ib-M6 against fourteen pathogenic strains of E. coli O157:H7. Susceptibility assay showed that Ib-M6 had values of Minimum Inhibitory Concentration (MIC) lower than streptomycin, used as a reference antibiotic. Moreover, to predict the possible interaction between Ib-M6 and outer membrane components of E. coli, we used molecular docking simulations where FhuA protein and its complex with Lipopolysaccharide (LPS-FhuA) were used as targets of the peptide. FhuA/Ib-M6 complexes had energy values between -39.5 and -40.5 Rosetta Energy Units (REU) and only one hydrogen bond. In contrast, complexes between LPS-FhuA and Ib-M6 displayed energy values between -25.6 and -40.6 REU, and the presence of five possible hydrogen bonds. Hence, the antimicrobial activity of Ib-M6 peptide shown in the experimental assays could be caused by its interaction with the outer membrane of E. coli.

Biopolymeric pellets of polyvinyl alcohol and alginate for the encapsulation of Ib-M6 peptide and its antimicrobial activity against E. coli.

The encapsulation of Ib-M6 antibacterial peptide in pellets of polyvinyl alcohol (PVA) and polyvinyl alcohol-alginate (PVA-Alg) matrices was carried out in order to explore its controlled release and activity against Escherichia coli K-12. The pellets were obtained by combined ice segregation induced self-assembly (ISISA) and freezing-thawing methods and their microstructure was studied by scanning electron microscopy. Bromothymol blue was used as a model compound to study the transport mechanisms and release from pellets. The results show that there is a significant effect of the total concentration of PVA precursor solutions, the mass ratio of PVA of different molecular weights and the addition of alginate on the microstructure and transport properties of pellets. The antibacterial activity of Ib-M6 against Escherichia coli K-12 was not affected by the encapsulation in PVA pellets. However, the release of Ib-M6 from PVA-Alg pellets was not possible, probably due to the electrostatic interaction of positively charged Ib-M6 and negatively alginate structure. Nonetheless, the controlled release of Ib-M6 from polymeric matrices can be fitting by modifying parameters such as the concentration and type of polymer precursors.

Surface diffusion and low vibrational motion with interacting adsorbates: a shot noise description.

Here, an approach in terms of shot noise is proposed to study and characterize surface diffusion and low vibrational motion when having interacting adsorbates on surfaces. In what we call statistical limit, that is, at long times and high number of collisions, one expects that diffusing particles display an essential Markovian behavior. Accordingly, the action of the pairwise potentials accounting for particle-particle collisions is equivalent to considering a shot noise acting on a single particle. We call this approach the interacting single adsorbate approximation, which gathers three important advantages: (i) the dynamics underlying surface diffusion and low vibrational motion can be easily understood in terms of relatively simple stochastic processes; (ii) from our model, appropriate (and well justified) working formulas are easily obtained, which explain the results arising from more complicated (but commonly used) molecular dynamics simulations within the Langevin formulation; and (iii), at the same time, it is less demanding computationally than the latter type of calculations. In order to illustrate the application of this model, numerical results are presented. Specially, our model reproduces the experimental observation regarding the broadening of the quasielastic peak ruling surface diffusion.

Line shape broadening in surface diffusion of interacting adsorbates with quasielastic he atom scattering.

The experimental line shape broadening observed in adsorbate diffusion on metal surfaces with increasing coverage is usually related to the nature of the adsorbate-adsorbate interaction. Here we show that this broadening can also be understood in terms of a fully stochastic model just considering two noise sources: (i) a Gaussian white noise accounting for the surface friction, and (ii) a shot noise replacing the physical adsorbate-adsorbate interaction potential. Furthermore, contrary to what could be expected, for relatively weak adsorbate-substrate interactions the opposite effect is predicted: line shapes get narrower with increasing coverage.

Generalized Chudley-Elliott vibration-jump model in activated atom surface diffusion.

Here the authors provide a generalized Chudley-Elliott expression for the activated atom surface diffusion which takes into account the coupling between both low-frequency vibrational motion (namely, the frustrated translational modes) and diffusion. This expression is derived within the Gaussian approximation framework for the intermediate scattering function at low coverage. Moreover, inelastic contributions (arising from creation and annihilation processes) to the full width at half maximum of the quasielastic peak are also obtained.

Quasi-elastic peak lineshapes in adsorbate diffusion on nearly flat surfaces at low coverages: the motional narrowing effect in Xe on Pt(111).

Quasi-elastic helium atom scattering measurements have provided clear evidence for a two-dimensional free gas of Xe atoms on Pt(111) at low coverages. Increasing the friction due to the surface, a gradual change of the shape of the quasi-elastic peak is predicted and analysed for this system in terms of the so-called motional narrowing effect. The type of analysis presented here for the quasi-elastic peak should be prior to any deconvolution procedure carried out in order to better extract information from the process, e.g. diffusion coefficients and jump distributions. Moreover, this analysis also provides conditions for the free gas regime different to those reported earlier.

Collisional line shapes for low frequency vibrations of adsorbates on a metal surface.

The dynamics of atoms or molecules adsorbed on a metal surface, and excited by collisions with an atomic beam, are treated within a theory that includes energy dissipation into lattice vibrations by means of a frequency and temperature dependent friction function. The theory provides dynamic structure factors for energy transfer derived from collisional time correlation functions. It describes the relaxation of a vibrationally excited atom or molecule within a model of a damped quantum harmonic oscillator bilinearly coupled to a bath of lattice oscillators. The collisional time correlation function is generalized to include friction effects and is applied to the vibrational relaxation of the frustrated translation mode of Na adsorbed on a Cu(001) surface, CO on Cu(001), and CO on Pt(111), following excitation by collisions with He atoms. Results for the frequency shift and width of line shapes versus surface temperature are in very good agreement with experimental measurements of inelastic He atom scattering. Our interpretation of the experimental results provides insight on the relative role of phonon versus electron-hole relaxation.

Hamiltonian theory for vibrational line shapes of atoms adsorbed on surfaces.

The vibrational motions of atomic adsorbates on surfaces can be probed by helium atom scattering. The experimental observable is the dynamic structure factor, which shows an inelastic peak around the vibrational frequency of the isolated adsorbates known as the frustrated translational or T-mode peak. In this paper we develop a theory for the line shape of this peak, as well as for its temperature-dependent shift and broadening, based on a Hamiltonian equivalent of the generalized Langevin equation. The theory can be used to infer physical parameters of the adatom-surface interaction, such as the friction coefficient, the barrier height to diffusion, and the anharmonicity parameter. Numerical simulations are used to ascertain the range of validity of the theory, which is also generalized to describe multidimensional systems and to include quantum corrections. We compare the theoretical predictions for the shift and broadening with experimental results for the Na/Cu(001) system, showing quantitative agreement within experimental resolution.

ISRS en el trastorno depresivo y otros trastornos

No disponible

[Clinical profile and prognosis of patients with endocarditis and periannular pseudoaneurysms]. / Perfil clínico y pronóstico de los pacientes con endocarditis y seudoaneurismas perianulares.

INTRODUCTION AND OBJECTIVES: Little information is available on the clinical profile and prognosis of patients with endocarditis and periannular pseudoaneurysms because the presence of pseudoaneurysm itself is considered an indication albeit not an evidence-based indication, for surgery. METHODS: We followed 18 patients (11 males, mean age: 5 +/- 4) with endocarditis and pseudoaneurysm diagnosed by transesophageal echocardiography and/or at surgery over 14 +/- 5 months. RESULTS: Aortic (n = 14; 6 on native valve, 8 on prosthesis) was more frequent than mitral (n = 3; 3 prosthesis) or tricuspid location (n = 1). Auriculoventricular block developed in 6 patients, all with aortic pseudoaneurysm. The most frequently involved microorganisms were staphylococci (n = 5) and streptococci (n = 5). Abscesses were found in 5 patients. Pseudoaneurysm was not considered an indication for surgery. Eleven patients underwent surgery 5 died after surgery (45%), 1 had reinfection and 5 are asymptomatic. The remaining 7 patients received only medical treatment: two died (28%), one developed reinfection and 4 are asymptomatic. The size of the pseudoaneurysm remained stable after 24 months of follow-up in the 4 asymptomatic medically treated patients (maximal diameter: 21 +/- 5 at diagnosis versus 22 +/- 5 at latest follow-up; p = NS). CONCLUSIONS: We conclude that the presence of a pseudoaneurysm identifies a subset of endocarditis patients with a high mortality. Pseudoaneurysms are usually located in an aortic position and around prosthetic material. Medical treatment without surgery should be considered when no other surgical indications exist. Lastly the size of a pseudoaneurysm in medically treated patients does not increase over time

Successful treatment of vasospastic angina with a coronary stent.

Calcium antagonists are the treatment of choice in vasospasm angina when no stenosis or mild stenosis are present. We present a case in which ergonovine echocardiography showed vasospasm of the right coronary artery despite optimal medical treatment. Stenting of a mild stenosis in that artery successfully controlled vasospasm and a pre-discharge ergonovine echocardiographic test was negative. The patient remains asymptomatic one year after stenting.

[Treatment with chlorambucil of renal amyloidosis secondary to rheumatoid arthritis. Study of 6 cases]. / Tratamiento con clorambucilo de la amiloidosis renal secundaria a artritis reumatoide. Estudio de 6 casos.

BACKGROUND: Amyloidosis is a common complication of rheumatoid arthritis. Renal disease is the main manifestation and its usual outcome is the lost of renal function. Some clinical evidences suggest that low-dose treatment with chlorambucil may be effective as therapy of this complication. PATIENTS AND METHODS: The effect of chlorambucil treatment in a group of six patients diagnosed by renal biopsy of renal amyloidosis secondary to rheumatoid arthritis was evaluated. Patients were treated with 0.1 mg/kg body weight/day for a time above a year until reduction of proteinuria. RESULTS: 3 out of 6 patients showed decrease of proteinuria below 500 mg/day, two patients have started renal replacement therapy and one died without response to treatment. It was detected non reversible azoospermia in one patient. Mean follow-up time has been sixty months. CONCLUSIONS: Chlorambucil may be effective in the treatment of renal amyloidosis secondary to rheumatoid arthritis when treatment starts before renal function is impaired. Long term remissions can be obtained even after suspending treatment.

[The prognostic value of dobutamine echocardiography after an uncomplicated acute myocardial infarct]. / Valor pronóstico de la ecocardiografía con dobutamina después de un infarto agudo de miocardio no complicado.

BACKGROUND AND PURPOSE: The identification of patients at risk for future events after an infarction is mandatory. The aim of this study was to assess the prognostic value of dobutamine stress echocardiography after an uncomplicated myocardial infarction. METHODS: One hundred and twenty five patients (mean age 65 +/- 11 years, males 82%) underwent dobutamine-echo within ten days after an uncomplicated myocardial infarction. Four myocardial responses were identified: a) negative; b) sustained improvement of myocardial contractility; c) initial improvement followed by worsening, and d) worsening at a distance or in the infarcted zone. RESULTS: Mean follow-up was 7.4 +/- 4.6 months. An adverse outcome occurred in 47 patients: non cardiac death in 3, cardiac death in 6, myocardial infarction in 5, angina in 21, congestive heart failure in 2, and in 10 patients revascularization. Cox regression analysis showed that worsening of contractility was the best predictor for adverse events (p < 0.0001, relative risk 2.8; 95% confidence interval: 1.7-4.5). Non-smoking and previous angina were also predictors of adverse events (p = 0.003 and p = 0.04, respectively). Similar results were obtained after excluding the revascularized patients. CONCLUSIONS: Sustained improvement of contractility in the infarcted region is not a predictor of adverse events. Asynergy at a distance or in the infarcted region during dobutamine echocardiography within ten days after an uncomplicated myocardial infarction predicts adverse cardiac events during follow-up. Therefore, dobutamine echocardiography could be used for risk stratification after acute myocardial infarction.

Clinical course, microbiologic profile, and diagnosis of periannular complications in prosthetic valve endocarditis.

Whether periannular extension of prosthetic valve endocarditis (abscesses, pseudoaneurysms, fistulas) is related to the etiologic agent, the clinical course and the prognosis is still unknown. Likewise, transesophageal echocardiographic accuracy in detecting periannular complications in prosthetic recipients remains unsettled. We retrospectively analyzed data from 87 patients with anatomically proven prosthetic valve endocarditis who underwent a transesophageal echocardiographic examination. Periannular complications (30 abscesses, 18 pseudoaneurysms, 8 fistulas; 8 with >1) were found in 46 patients; results were compared with the remaining 41 without complications. Transesophageal echocardiography correctly identified 27 abscesses (90%) and all pseudoaneurysms and fistulas. One diagnosis of pseudoaneurysm by echocardiography was not found at surgery. No statistical differences were found regarding age, sex, type of prosthesis (mechanical vs biologic), and etiologic agent. Periannular complications were more frequent in aortic location (70% vs 20% in mitral position; p <0.001) and in early (within 6 months after surgery) endocarditis (63% vs 38% in late endocarditis; p = 0.04). The same percentage of patients from both groups underwent surgery (98% with and 90% without complications). At discharge, 62% and 67% of patients were alive, respectively. Thus, periannular complications in prosthetic valve endocarditis are more frequent in aortic location and within 6 months after surgery. Neither the type of prosthesis nor the etiologic agent are related to the presence of periannular complications. Short-term prognosis in patients who underwent surgery is not affected by the presence of periannular complications.

Levy-nearest-neighbors Bak-Sneppen model.

We study a random neighbor version of the Bak-Sneppen model, where "nearest neighbors" are chosen according to a probability distribution decaying as a power law of the distance from the active site, P(x) approximately x-x(ac)(-omega). All of the exponents characterizing the self-organized critical state of this model depend on the exponent omega. As omega-->1 we recover the usual random nearest-neighbor version of the model. The pattern of results obtained for a range of values of omega is also compatible with the results of simulations of the original BS model in high dimensions. Moreover, our results suggest a critical dimension dc=6 for the Bak-Sneppen model, in contrast with previous claims.