Seguridad del paciente en Resonancia Magnética / Patient safety in magnetic resonance imaging

El uso de campos magnéticos estáticos, gradientes de campo y ondas de radiofrecuencia suponen un reto de seguridad diferente a otras modalidades de imagen. Cada vez más centros trabajan con equipos de 3,0T que presentan mayores riesgos para el paciente frente a los de 1,5T. Hay una necesidad de actualización para el personal de radiología que le permita entender los riesgos y disminuirlos, pues pueden producirse incidentes graves e incluso mortales. El objetivo de este trabajo es presentar una revisión y actualización de los riesgos a los que se ven sometidos los pacientes durante la realización de un estudio de resonancia magnética.(AU)

Image acquisition involves the use of static magnetic fields, field gradients and radiofrequency waves. These elements make the MRI a different modality. More and more centers work with 3.0 T equipment that present higher risks for the patient, compared to those of 1.5 T. Therefore, there is a need for updating for radiology staff that allows them to understand the risks and reduce them, since serious and even fatal incidents can occur. The objective of this work is to present a review and update of the risks to which patients are subjected during the performance of a magnetic resonance imaging study.(AU)

Patient safety in magnetic resonance imaging.

Image acquisition involves the use of static magnetic fields, field gradients and radiofrequency waves. These elements make the MRI a different modality. More and more centers work with 3.0 T equipment that present higher risks for the patient, compared to those of 1.5 T. Therefore, there is a need for updating for radiology staff that allows them to understand the risks and reduce them, since serious and even fatal incidents can occur. The objective of this work is to present a review and update of the risks to which patients are subjected during the performance of a magnetic resonance imaging (MRI) study.

Infección por SARS-CoV-2 en pacientes con o en riesgo de infecciones venéreas: estudio de su incidencia y factores asociados en un centro monográfico de infecciones de transmisión sexual / SARS-CoV-2 infection in patients with or at risk for venereal infections: Incidence and associated factors in a sexual health clinic

Antecedentes y objetivo El SARS-CoV-2 se transmite con más facilidad por cercanía física, inherente a las relaciones sexuales, lo que ha hecho plantearse que pueda haber una mayor incidencia de COVID-19 en personas con infecciones venéreas o de transmisión sexual (ITS) o en riesgo de adquirirlas. Por este motivo, buscamos estimar la seroprevalencia de anticuerpos frente a SARS-CoV-2 en personas que acuden a una consulta monográfica de ITS, comparar dicha seroprevalencia con la estimada en nuestra región y estudiar los factores asociados. Material y método Estudio observacional transversal que incluye a pacientes mayores de 18 años aún no vacunados atendidos en una consulta monográfica municipal de ITS para estudio o cribado, incluidos de forma consecutiva de marzo a abril de 2021. Se realizó test serológico rápido para SARS-CoV-2 y se recogieron variables demográficas, sociales y sexuales, diagnósticos de ITS y antecedentes de síntomas compatibles con infección por SARS-CoV-2. Resultados Se incluyó a 512 pacientes, el 37% mujeres. Tuvieron alguna prueba positiva a SARS-CoV-2 124 pacientes (24,2%). Se relacionaron con un resultado positivo: el uso de mascarillas tipo FFP2 (OR 0,50) y el número de parejas sexuales superior a la mediana (OR 1,80). El uso de mascarillas FFP2 no se distribuyó de manera aleatoria en la muestra. Conclusiones La población sexualmente activa ha tenido pruebas positivas a SARS-CoV-2 con más frecuencia que la población general. La principal vía de contagio en este grupo parece ser la vía respiratoria, por lo que la transmisión sexual es probablemente limitada y está relacionada con la proximidad que implican las relaciones sexuales (AU)

Background and objective SARS-CoV-2 is more easily spread by close contact, which is inherent to sexual intercourse. People with, or at risk for, sexually transmitted infections (STIs) may therefore have higher rates of COVID-19. The aim of this study was to estimate SARS-CoV-2 antibody seroprevalence in people seen at a dedicated STI clinic, compare our findings to the estimated seroprevalence in the local general population, and study factors associated with SARS-CoV-2 infection in this setting. Material and methods Cross-sectional observational study including consecutive patients older than 18 years of age who had not yet been vaccinated against COVID-19 and who underwent examination or screening at a dedicated municipal STI clinic in March and April 2021. We ordered rapid SARS-CoV-2 serology and collected information on demographic, social, and sexual variables, STI diagnoses, and history of symptoms compatible with SARS-CoV-2 infection. Results We studied 512 patients (37% women). Fourteen (24.2%) had a positive SARS-CoV-2 test. Variables associated with positivity were use of FFP2 masks (odds ratio 0.50) and a higher-than-average number of sexual partners (odds ratio 1.80). Use of FFP2 masks was not randomly distributed in this sample. Conclusions Sexually active members of the population in this study had a higher incidence of SARS-CoV-2 infection than the general population. The main route of infection in this group appears to be respiratory, linked to close contact during sexual encounters; sexual transmission of the virus is probably limited (AU)

[Translated article] SARS-CoV-2 Infection in Patients With or at Risk for Venereal Infections: Incidence and Associated Factors in a Sexual Health Clinic / Infección por SARS-CoV-2 en pacientes con o en riesgo de infecciones venéreas: estudio de su incidencia y factores asociados en un centro monográfico de infecciones de transmisión sexual

Background and objective SARS-CoV-2 is more easily spread by close contact, which is inherent to sexual intercourse. People with, or at risk for, sexually transmitted infections (STIs) may therefore have higher rates of COVID-19. The aim of this study was to estimate SARS-CoV-2 antibody seroprevalence in people seen at a dedicated STI clinic, compare our findings to the estimated seroprevalence in the local general population, and study factors associated with SARS-CoV-2 infection in this setting. Material and methods Cross-sectional observational study including consecutive patients older than 18 years of age who had not yet been vaccinated against COVID-19 and who underwent examination or screening at a dedicated municipal STI clinic in March and April 2021. We ordered rapid SARS-CoV-2 serology and collected information on demographic, social, and sexual variables, STI diagnoses, and history of symptoms compatible with SARS-CoV-2 infection. Results We studied 512 patients (37% women). Fourteen (24.2%) had a positive SARS-CoV-2 test. Variables associated with positivity were use of FFP2 masks (odds ratio 0.50) and a higher-than-average number of sexual partners (odds ratio 1.80). Use of FFP2 masks was not randomly distributed in this sample. Conclusions Sexually active members of the population in this study had a higher incidence of SARS-CoV-2 infection than the general population. The main route of infection in this group appears to be respiratory, linked to close contact during sexual encounters; sexual transmission of the virus is probably limited (AU)

Antecedentes y objetivo El SARS-CoV-2 se transmite con más facilidad por cercanía física, inherente a las relaciones sexuales, lo que ha hecho plantearse que pueda haber una mayor incidencia de COVID-19 en personas con infecciones venéreas o de transmisión sexual (ITS) o en riesgo de adquirirlas. Por este motivo, buscamos estimar la seroprevalencia de anticuerpos frente a SARS-CoV-2 en personas que acuden a una consulta monográfica de ITS, comparar dicha seroprevalencia con la estimada en nuestra región y estudiar los factores asociados. Material y método Estudio observacional transversal que incluye a pacientes mayores de 18 años aún no vacunados atendidos en una consulta monográfica municipal de ITS para estudio o cribado, incluidos de forma consecutiva de marzo a abril de 2021. Se realizó test serológico rápido para SARS-CoV-2 y se recogieron variables demográficas, sociales y sexuales, diagnósticos de ITS y antecedentes de síntomas compatibles con infección por SARS-CoV-2. Resultados Se incluyó a 512 pacientes, el 37% mujeres. Tuvieron alguna prueba positiva a SARS-CoV-2 124 pacientes (24,2%). Se relacionaron con un resultado positivo: el uso de mascarillas tipo FFP2 (OR 0,50) y el número de parejas sexuales superior a la mediana (OR 1,80). El uso de mascarillas FFP2 no se distribuyó de manera aleatoria en la muestra. Conclusiones La población sexualmente activa ha tenido pruebas positivas a SARS-CoV-2 con más frecuencia que la población general. La principal vía de contagio en este grupo parece ser la vía respiratoria, por lo que la transmisión sexual es probablemente limitada y está relacionada con la proximidad que implican las relaciones sexuales (AU)

SARS-CoV-2 infection in patients with or at risk for venereal infections: Incidence and associated factors in a sexual health clinic. / Infección por SARS-CoV-2 en pacientes con o en riesgo de infecciones venéreas: estudio de su incidencia y factores asociados en un centro monográfico de infecciones de transmisión sexual.

BACKGROUND AND OBJECTIVE: SARS-CoV-2 is more easily spread by close contact, which is inherent to sexual intercourse. People with, or at risk for, sexually transmitted infections (STIs) may therefore have higher rates of COVID-19. The aim of this study was to estimate SARS-CoV-2 antibody seroprevalence in people seen at a dedicated STI clinic, compare our findings to the estimated seroprevalence in the local general population, and study factors associated with SARS-CoV-2 infection in this setting. MATERIAL AND METHODS: Cross-sectional observational study including consecutive patients older than 18 years of age who had not yet been vaccinated against COVID-19 and who underwent examination or screening at a dedicated municipal STI clinic in March and April 2021. We ordered rapid SARS-CoV-2 serology and collected information on demographic, social, and sexual variables, STI diagnoses, and history of symptoms compatible with SARS-CoV-2 infection. RESULTS: We studied 512 patients (37% women). Fourteen (24.2%) had a positive SARS-CoV-2 test. Variables associated with positivity were use of FFP2 masks (odds ratio 0.50) and a higher-than-average number of sexual partners (odds ratio 1.80). Use of FFP2 masks was not randomly distributed in this sample. CONCLUSIONS: Sexually active members of the population in this study had a higher incidence of SARS-CoV-2 infection than the general population. The main route of infection in this group appears to be respiratory, linked to close contact during sexual encounters; sexual transmission of the virus is probably limited.

First report of multiple Rickettsia sp., Anaplasma sp., and Ehrlichia sp. in the San Miguel Department of El Salvador from zoonotic tick vectors.

Neglected bacterial zoonoses are a group of Neglected Tropical Diseases (NTDs) that are commonly underdiagnosed and underreported due to their undifferentiated febrile illness symptomology. Spotted fever group rickettsioses (SFGR), a subset of tick-borne bacterial zoonoses, belong in this group. There is a dichotomy in the reporting and recognition of these pathogens in Central America: countries with reduced human development scores-like El Salvador-have little to no research or surveillance dedicated to these pathogens and the diseases they cause. This was the third-ever tick survey in El Salvador, highlighting the knowledge gap in this country. A total of 253 ticks were collected from 11 animals at two farm sites and one veterinary office. Standard and quantitative PCR were used to detect presence of SFGR, Ehrlichia, and Anaplasma sp. pathogens in ticks. Ehrlichia sp. were detected in 2.4% of all collected ticks and Anaplasma sp. were detected in 5.5% of all ticks. Rickettsia rickettsii was amplified in 18.2% of ticks, and amplicons similar to R. parkeri, and R. felis were found in 0.8% and 0.4%, of collected ticks, respectively. This is the first report of these pathogenic bacterial species in El Salvador. This study emphasizes the need for further surveillance and research including incorporating additional human seroprevalence and testing to understand the public health burden in this country.

Asociación entre los polimorfismos genéticos de nucleótido único en genes transportadores ABC con la epilepsia farmacorresistente en la población española / Association between single nucleotide genetic polymorphisms in ABC transporter genes with drug-resistant epilepsy in the Spanish population

Introducción: El 30% de los pacientes con epilepsia no responde al tratamiento farmacológico. La presencia de polimorfismos genéticos de nucleótido único (SNP) en el individuo puede influir en la variabilidad de respuesta al tratamiento farmacológico. La hipótesis de transportadores plantea que la presencia de SNP en los genes que codifican las proteínas ABC repercutiría en la biodisponibilidad de los fármacos anticrisis en el foco epileptógeno, lo que ocasionaría refractariedad. El objetivo del presente estudio fue evaluar la asociación de 13 polimorfismos en los genes ABCB1, ABCC2, ABCC5 y ABCG2 con la epilepsia farmacorresistente (EFR) en población española. Sujetos y métodos: Se realizó un estudio de casos y controles que incluyó a 327 pacientes con epilepsia: 227 farmacorresistentes y 100 farmacocontrolados según los criterios de la Liga Internacional contra la Epilepsia. En el ADN de leucocitos de sangre periférica extraído se estudiaron los polimorfismos en los genes transportadores ABC. Se utilizó la plataforma tecnológica iPlex® Gold y Mass ARRAY. Se compararon las frecuencias alélicas y genotípicas del grupo de casos y del de controles, el valor de p, la odds ratio y los intervalos de confianza al 95%. Resultados: La frecuencia alélica y genotípica del presente estudio fue similar a la comunicada en las bases de datos poblacionales. En los SNP estudiados no se encontraron diferencias significativas (p > 0,05) en todos los modelos de herencia analizados. Conclusiones: Nuestros resultados sugieren que no existe asociación entre los polimorfismos analizados en los genes ABC con la EFR en población española. Sin embargo, otros estudios adicionales confirmarán o descartarán estos resultados.(AU)

Introduction: Almost a third of all patients with epilepsy (30%) fail to respond to pharmacological treatment. The presence of single nucleotide polymorphisms (SNPs) in the individual may influence the variability of the response to drug treatment. The transporter hypothesis posits that the presence of SNPs in the genes encoding ABC proteins would affect the bioavailability of antiseizure drugs at the epileptogenic focus, giving rise to refractoriness. The aim of the present study was to evaluate the association of 13 polymorphisms in the ABCB1, ABCC2, ABCC5 and ABCG2 genes with drug-resistant epilepsy (DRE) in a Spanish population. Subjects and methods: A case-control study was conducted involving 327 patients with epilepsy: 227 resistant to drug therapy and 100 in whom their medication enabled them to control their symptoms, according to International League Against Epilepsy criteria. In the peripheral blood leukocyte DNA that was extracted, polymorphisms in the ABC transporter genes were studied. The iPlex® Gold and Mass ARRAY technology platform was used. The allele and genotypic frequencies of the case and control groups, p-value, odds ratio and 95% confidence intervals were compared. Results: The allele and genotypic frequency of the present study was similar to that reported in population-based databases. For the SNPs studied, no significant differences (p > 0.05) were found in any of the inheritance models analysed. Conclusions: Our results suggest that there is no association between the polymorphisms analysed in the ABC genes and DRE in the Spanish population. Nevertheless, further studies will confirm or refute these results.(AU)

[Association between single nucleotide genetic polymorphisms in ABC transporter genes with drug-resistant epilepsy in the Spanish population]. / Asociación entre los polimorfismos genéticos de nucleótido único en genes transportadores ABC con la epilepsia farmacorresistente en la población española.

INTRODUCTION: Almost a third of all patients with epilepsy (30%) fail to respond to pharmacological treatment. The presence of single nucleotide polymorphisms (SNPs) in the individual may influence the variability of the response to drug treatment. The transporter hypothesis posits that the presence of SNPs in the genes encoding ABC proteins would affect the bioavailability of antiseizure drugs at the epileptogenic focus, giving rise to refractoriness. The aim of the present study was to evaluate the association of 13 polymorphisms in the ABCB1, ABCC2, ABCC5 and ABCG2 genes with drug-resistant epilepsy (DRE) in a Spanish population. SUBJECTS AND METHODS: A case-control study was conducted involving 327 patients with epilepsy: 227 resistant to drug therapy and 100 in whom their medication enabled them to control their symptoms, according to International League Against Epilepsy criteria. In the peripheral blood leukocyte DNA that was extracted, polymorphisms in the ABC transporter genes were studied. The iPlex® Gold and Mass ARRAY technology platform was used. The allele and genotypic frequencies of the case and control groups, p-value, odds ratio and 95% confidence intervals were compared. RESULTS: The allele and genotypic frequency of the present study was similar to that reported in population-based databases. For the SNPs studied, no significant differences (p > 0.05) were found in any of the inheritance models analysed. CONCLUSIONS: Our results suggest that there is no association between the polymorphisms analysed in the ABC genes and DRE in the Spanish population. Nevertheless, further studies will confirm or refute these results.

TITLE: Asociación entre los polimorfismos genéticos de nucleótido único en genes transportadores ABC con la epilepsia farmacorresistente en la población española.Introducción. El 30% de los pacientes con epilepsia no responde al tratamiento farmacológico. La presencia de polimorfismos genéticos de nucleótido único (SNP) en el individuo puede influir en la variabilidad de respuesta al tratamiento farmacológico. La hipótesis de transportadores plantea que la presencia de SNP en los genes que codifican las proteínas ABC repercutiría en la biodisponibilidad de los fármacos anticrisis en el foco epileptógeno, lo que ocasionaría refractariedad. El objetivo del presente estudio fue evaluar la asociación de 13 polimorfismos en los genes ABCB1, ABCC2, ABCC5 y ABCG2 con la epilepsia farmacorresistente (EFR) en población española. Sujetos y métodos. Se realizó un estudio de casos y controles que incluyó a 327 pacientes con epilepsia: 227 farmacorresistentes y 100 farmacocontrolados según los criterios de la Liga Internacional contra la Epilepsia. En el ADN de leucocitos de sangre periférica extraído se estudiaron los polimorfismos en los genes transportadores ABC. Se utilizó la plataforma tecnológica iPlex® Gold y Mass ARRAY. Se compararon las frecuencias alélicas y genotípicas del grupo de casos y del de controles, el valor de p, la odds ratio y los intervalos de confianza al 95%. Resultados. La frecuencia alélica y genotípica del presente estudio fue similar a la comunicada en las bases de datos poblacionales. En los SNP estudiados no se encontraron diferencias significativas (p > 0,05) en todos los modelos de herencia analizados. Conclusiones. Nuestros resultados sugieren que no existe asociación entre los polimorfismos analizados en los genes ABC con la EFR en población española. Sin embargo, otros estudios adicionales confirmarán o descartarán estos resultados.

Abattoir Factors Influencing the Incidence of Dark Cutting in Australian Grain-Fed Beef.

The aim of this study was to evaluate the effect of carcass traits, lairage time and weather conditions during lairage and abattoir factors that impact the incidence of dark cutting in 142,228 grain-fed carcasses, as defined by Meat Standards Australia (MSA) guidelines. This study was conducted over a 12-month period analysing data from cattle that were supplied from seven feedlots and processed at three abattoirs. Abattoir data indicated that the average incidence of dark cutting within the study was 2.8%. Increased wind speeds (WSs) and rain during lairage at the abattoir was associated with an increased risk of dark cutting, whereas variation in ambient temperature and/or relative humidity did not influence dark cutting. Heavier carcasses with whiter fat, larger hump heights, more rib fat, higher marble scores and lower ossification had lower incidences of dark cutting. The factors abattoir, time in lairage, time to grading and grader within Abattoir had significant effects on the incidence of dark cutting. The results from this study suggest that reducing the time in lairage and increasing the time between slaughter and grading are the two major ways to reduce dark cutting in MSA carcasses.

Androgen deprivation-induced elevated nuclear SIRT1 promotes prostate tumor cell survival by reactivation of AR signaling.

The NAD+-dependent deacetylase, Sirtuin 1 (SIRT1) is involved in prostate cancer pathogenesis. However, the actual contribution is unclear as some reports propose a protective role while others suggest it is harmful. We provide evidence for a contextual role for SIRT1 in prostate cancer. Our data show that (i) mice orthotopically implanted with SIRT1-silenced LNCaP cells produced smaller tumors; (ii) SIRT1 suppression mimicked AR inhibitory effects in hormone responsive LNCaP cells; and (iii) caused significant reduction in gene signatures associated with E2F and MYC targets in AR-null PC-3 and E2F and mTORC1 signaling in castrate-resistant ARv7 positive 22Rv1 cells. Our findings further show increased nuclear SIRT1 (nSIRT1) protein under androgen-depleted relative to androgen-replete conditions in prostate cancer cell lines. Silencing SIRT1 resulted in decreased recruitment of AR to PSA enhancer selectively under androgen-deprivation conditions. Prostate cancer outcome data show that patients with higher levels of nSIRT1 progress to advanced disease relative to patients with low nSIRT1 levels. Collectively, we demonstrate that lowering SIRT1 levels potentially provides new avenues to effectively prevent prostate cancer recurrence.

Rationale, design and methodology of TESEO study: a registry of thrombosis and neoplasia of SEOM (Spanish Society of Medical Oncology).

BACKGROUND AND RATIONALE: Thromboembolic complications are a serious, preventable and common event in cancer patients that contributes to increasing morbidity and mortality. Despite increasing knowledge on cancer-associated thrombosis (CAT), there are still several aspects of diagnosis, clinical management, treatment and prognosis with uncertainties that are under-represented in randomized clinical trials. For this reason, the Spanish Society of Medical Oncology (SEOM) launched in June 2018 a registry of CAT. METHODS/DESIGN: TESEO is an ongoing prospective, non-interventional, multicentric study in consecutive cancer patients with newly diagnosed of thromboembolic event (TEE). Eligibility criteria include being > 18 years with a histologically confirmed diagnosis of cancer and a symptomatic or incidental TEE confirmed with an imaging technique in the previous month or any time after the cancer diagnosis and signing of informed consent. The study consists of two types of integrated but independent prospective registries. Regular CAT sub-registry includes information on patient's cancer´s characteristics, anticoagulant treatment provided and outcome data. Special CAT sub-registry includes variables related to special situations of CAT that comprise patients with severe kidney failure, thrombocytopenia, high risk of bleeding related to the cancer or with coexistence of bleeding and patients who receive new treatments such a targeted therapy, antiangiogenics agents and immunotherapy. The registry considers the status of the cancer and the time to assess how the prognosis is changed based on when the thrombus occurs. Some outcomes such as rethrombosis, major bleeding, tumor progression and survival will be valued in various time intervals including 1, 3, 6 and 12 months after the even in the first year; and then every 6 months until the patient's death. RESULTS: After 18 months and with 35 centers and researchers, the registry has 1128 patients. CONCLUSION: TESEO registry will provide clinical real-world evidence for prevention, treatment and complications of CAT in different scenarios that are under-represented in randomized clinical trials.

Localized structures formed through domain wall locking in cavity-enhanced second-harmonic generation.

We analyze the formation of localized structures in cavity-enhanced second-harmonic generation. We focus on the phase-matched limit, and consider that fundamental and generated waves have opposite signs of group velocity dispersion. We show that these states form due to the locking of domain walls connecting two stable homogeneous states of the system, and undergo collapsed snaking. We study the impact of temporal walk-off on the stability and dynamics of these localized states.

Nonlocal Raman response in Kerr resonators: Moving temporal localized structures and bifurcation structure.

A ring resonator made of a silica-based optical fiber is a paradigmatic system for the generation of dissipative localized structures or dissipative solitons. We analyze the effect of the non-instantaneous nonlinear response of the fused silica or the Raman response on the formation of localized structures. After reducing the generalized Lugiato-Lefever to a simple and generic bistable model with a nonlocal Raman effect, we investigate analytically the formation of moving temporal localized structures. This reduction is valid close to the nascent bistability regime, where the system undergoes a second-order critical point marking the onset of a hysteresis loop. The interaction between fronts allows for the stabilization of temporal localized structures. Without the Raman effect, moving temporal localized structures do not exist, as shown in M. G. Clerc, S. Coulibaly, and M. Tlidi, Phys. Rev. Res. 2, 013024 (2020). The detailed derivation of the speed and the width associated with these structures is presented. We characterize numerically in detail the bifurcation structure and stability associated with the moving temporal localized states. The numerical results of the governing equations are in close agreement with analytical predictions.

Formation of localized states in dryland vegetation: Bifurcation structure and stability.

We study theoretically the emergence of localized states of vegetation close to the onset of desertification. These states are formed through the locking of vegetation fronts, connecting a uniform vegetation state with a bare soil state, which occurs nearby the Maxwell point of the system. To study these structures we consider a universal model of vegetation dynamics in drylands, which has been obtained as the normal form for different vegetation models. Close to the Maxwell point localized gaps and spots of vegetation exist and undergo collapsed snaking. The presence of gaps strongly suggest that the ecosystem may undergo a recovering process. In contrast, the presence of spots may indicate that the ecosystem is close to desertification.

[Bases of deep brain stimulation]. / Bases de la estimulación cerebral profunda.

INTRODUCTION: Deep brain stimulation is an effective therapy that is being used in an increasing number of indications. The mechanisms by which it exerts its therapeutic effect are still largely unknown, although there is increasing evidence of its influence at various levels. AIM: To review the existing literature on the mechanism of action of deep brain stimulation. DEVELOPMENT: Deep brain stimulation acts on brain tissue that is stimulated at various levels: molecular, cellular and neural networks. Spatial, temporal and electrical factors are involved in its effectiveness, but it mainly seems to perform its function by replacing anomalous firing patterns, which are present in certain neurological and psychiatric diseases. Other mechanisms, such as neuroprotection or neurogenesis, remain under study. CONCLUSIONS: Although many of the effects by which deep brain stimulation acts on the brain are still unknown, it seems to be a complex treatment, with large-scale effects, in which the correction of circuitopathies seems to prevail as the main mechanism.

TITLE: Bases de la estimulación cerebral profunda.Introducción. La estimulación cerebral profunda es una terapia eficaz que está siendo utilizada en un número creciente de indicaciones. Los mecanismos mediante los cuales ejerce efecto terapéutico aún se desconocen en su mayor parte, si bien cada vez se dispone de más datos sobre su influencia en diversos niveles. Objetivo. Revisar la bibliografía existente sobre el mecanismo de acción de la estimulación cerebral profunda. Desarrollo. La estimulación cerebral profunda actúa sobre el tejido cerebral estimulado en varios niveles, molecular, celular y de redes neuronales. En su efectividad intervienen factores espaciales, temporales y eléctricos, pero fundamentalmente parece ejercer su función mediante la sustitución de patrones de disparo anómalos, presentes en ciertas enfermedades neurológicas y psiquiátricas. Otros mecanismos, como la neuroprotección o la neurogénesis, permanecen en estudio. Conclusiones. Aunque aún se desconocen muchos efectos por los cuales la estimulación cerebral profunda actúa en el cerebro, parece un tratamiento complejo, con efectos a gran escala, en los que parece primar la corrección de circuitopatías como mecanismo principal.

[Deep brain stimulation in drug-resistant epilepsy]. / Estimulación cerebral profunda en la epilepsia farmacorresistente.

INTRODUCTION: Deep brain stimulation (DBS) in drug-resistant epilepsy has been applied to several brain targets. However, its exact mechanism of action is not known, and the diversity of targets makes it difficult to know the degree of evidence that supports its use. DEVELOPMENT: A review of the literature on DBS for drug-resistant epilepsy was conducted. The efficacy of DBS in drug-resistant epilepsy seems to be mediated by a desynchronisation of neuronal activity at the epileptogenic focus or a modulation of the «circuitopathies¼ that exist in epilepsy, depending on the target. In DBS multiple cortical and subcortical structures have been used, but class I evidence exists only for DBS of the anterior nucleus of the thalamus. CONCLUSIONS: DBS in epilepsy is still under investigation, with class I evidence for DBS of the anterior nucleus of the thalamus. The rest of the targets have yielded variable results that must be confirmed with randomised designs in larger series.

TITLE: Estimulación cerebral profunda en la epilepsia farmacorresistente.Introducción. La estimulación cerebral profunda (ECP) en la epilepsia farmacorresistente se ha aplicado en varias dianas cerebrales. Sin embargo, su mecanismo de acción no se conoce con exactitud, y la diversidad de dianas hace difícil conocer el grado de evidencia que apoya su utilización. Desarrollo. Se realiza una revisión bibliográfica sobre la ECP para la epilepsia farmacorresistente. La eficacia de la ECP en la epilepsia farmacorresistente parece mediada por una desincronización de la actividad neuronal en el foco epileptógeno o una modulación de las circuitopatías que existen en la epilepsia, dependiendo de la diana. En la ECP se han utilizado múltiples estructuras corticales y subcorticales, pero solamente la ECP del núcleo anterior del tálamo tiene una evidencia de clase I. Conclusiones. La ECP en la epilepsia es aún objeto de investigación, con evidencia de clase I en la ECP del núcleo anterior del tálamo. El resto de las dianas ha arrojado resultados variables que deben confirmarse con diseños aleatorizados en series de mayor tamaño.

Localized structures in dispersive and doubly resonant optical parametric oscillators.

We study temporally localized structures in doubly resonant degenerate optical parametric oscillators in the absence of temporal walk-off. We focus on states formed through the locking of domain walls between the zero and a nonzero continuous-wave solution. We show that these states undergo collapsed snaking and we characterize their dynamics in the parameter space.

[Is it possible to extract intracranial pressure information based on the EEG activity?] / Es posible obtener informacion de la presion intracraneal a partir de la actividad electroencefalografica?

INTRODUCTION: The capability of the electroencephalography (EEG) of recording the bioelectrical activity of the brain has made of it a fundamental tool for the evaluation of the patient's neurological condition. In recent years, moreover, it has also begun to be used in obtaining information for other kind of variables, as the ones related with the cerebral hemodynamics. AIM: To study the potential relationship between the EEG activity and the intracranial pressure (ICP) in patients suffering from traumatic brain injury and subarachnoid hemorrhage, during their stay at the intensive care unit. PATIENTS AND METHODS: Twenty-one adult patients (10 women) were included in the present observational prospective cohort study. They suffered from either traumatic brain injury or subarachnoid hemorrhage, requiring continuous EEG and ICP monitoring. In every patient, Granger causality between spectral functions of the EEG and the ICP was evaluated. Temporal windows of 10 minute were used to evaluate whether a causal relationship between those variables exist or not. In all of the cases, several days of continuous recording and assessment were performed. RESULTS: In most patients and during most of the time, Granger causality turns out to be significant in the direction from the EEG to the ICP, meaning that the EEG dynamics actually leads the ICP dynamics. CONCLUSIONS: The present work provides useful information and shed light in discovering a hidden relationship between the ICP and EEG dynamics. The potential use of this relationship could lead to develop a medical device to measure ICP in a non-invasive fashion.

TITLE: Es posible obtener informacion de la presion intracraneal a partir de la actividad electroencefalografica?Introduccion. El electroencefalograma (EEG) permite obtener informacion directa de la actividad bioelectrica del cerebro y es una herramienta fundamental para la evaluacion de la condicion neurologica del paciente. En los ultimos años ha comenzado a emplearse tambien para obtener indirectamente informacion sobre la hemodinamica cerebral y las variables que intervienen en la autorregulacion del flujo sanguineo cerebral. Objetivo. Estudiar la posible relacion entre la actividad electroencefalografica y la presion intracraneal (PIC) en pacientes con traumatismo craneoencefalico y hemorragia subaracnoidea ingresados en cuidados intensivos. Pacientes y metodos. Se incluyo a 21 pacientes (10 mujeres) mayores de 18 años con traumatismo craneoencefalico o hemorragia subaracnoidea que requerian monitorizacion de la PIC y a los que se les registro el EEG de forma continua. Se determino la causalidad de Granger entre la PIC con respecto a las variables espectrales del EEG para ventanas temporales de 10 minutos durante la estancia en cuidados intensivos. Resultados. La causalidad de Granger mostro una alta correlacion entre la PIC con las bandas del EEG. En la mayoria de los pacientes existe una causalidad de Granger significativa en la direccion del EEG hacia la PIC en gran parte del tiempo de monitorizacion, de forma que las variables del EEG precedian a la PIC. Conclusiones. El presente trabajo expone la relacion temporal subyacente entre la dinamica de la PIC y la actividad bioelectrica cerebral registrada mediante EEG en pacientes con traumatismo craneoencefalico y hemorragia subaracnoidea. El potencial uso de esta relacion podria permitir estimar la PIC de manera no invasiva.

Bifurcation structure of localized states in the Lugiato-Lefever equation with anomalous dispersion.

The origin, stability, and bifurcation structure of different types of bright localized structures described by the Lugiato-Lefever equation are studied. This mean field model describes the nonlinear dynamics of light circulating in fiber cavities and microresonators. In the case of anomalous group velocity dispersion and low values of the intracavity phase detuning these bright states are organized in a homoclinic snaking bifurcation structure. We describe how this bifurcation structure is destroyed when the detuning is increased across a critical value, and determine how a bifurcation structure known as foliated snaking emerges.