Challenges and lessons learned from a long-term postauthorisation safety study programme of rivaroxaban in Europe.

OBJECTIVES: To describe opportunities and challenges experienced from the four pharmacoepidemiological database studies included in the rivaroxaban post authorisation safety study (PASS) programme and propose ways to maximise the value of population-based observational research when addressing regulatory requirements. DESIGN: PASS programme of rivaroxaban carried out as part of the regulatory postapproval commitment to the European Medicines Agency. SETTING: Clinical practice in Germany, the Netherlands, Sweden and the UK (electronic health records)-undertaken by pharmacoepidemiology research teams using country-specific databases with different coding structures. PARTICIPANTS: 355 152 patients prescribed rivaroxaban and 338 199 patients prescribed vitamin K antagonists. RESULTS: Two major challenges that were encountered throughout the lengthy PASS programme were related to: (1) finalising country-tailored study designs before the extent of rivaroxaban uptake was known, and (2) new research questions that arose during the programme (eg, those relating to an evolving prescribing landscape). RECOMMENDATIONS: We advocate the following strategies to help address these major challenges (should they arise in any future PASS): conducting studies based on a common data model that enable the same analytical tools to be applied when using different databases; maintaining early, clear, continuous communication with the regulator (including discussing the potential benefit of studying drug use as a precursor to planning a safety study); consideration of adaptive designs whenever uncertainty exists and following an initial period of data collection; and setting milestones for the review of study objectives.

Barriers in Access to Idarucizumab in Ischemic Stroke in a Middle-Income Country.

Background and Purpose: Current stroke guidelines contraindicate the use of thrombolytics if oral anticoagulants are taken within 48 hours of symptom onset. Idarucizumab is an alternative for patients on dabigatran who experience an acute stroke, so that alteplase may be used. However, this treatment may not be readily available in low/middle-income countries. Our objective is to describe barriers to access to the administration of idarucizumab. Methods: We applied a structured survey for health personnel, consulted databases of drug providers, and analyzed reports from the National Pharmacologic Surveillance Data to describe idarucizumab use and the related knowledge among prescribers and the drug distribution in health institutions in Colombia between January 2018 and January 2022. Results: In total, 23.6% of the 337 interviewed physicians' hospitals had access to idarucizumab, and 34.9% of the physicians were unaware of the use of this medication for ischemic stroke. Only 11 private institutions had access to this medication in Colombia. Four male patients with atrial fibrillation received thrombolytics for acute stroke, and two required subsequent mechanical thrombectomy. No fatal complications during hospitalization were observed. Complications included hematuria, hemorrhagic transformation and groin hematoma. None required transfusion or further intervention. All had favorable mRS scores at the 90-day follow-up. Conclusions: There are multiple barriers to access idarucizumab in Colombia. The main factors identified are the low medication availability in provincial hospitals and the low medical knowledge. However clinical results in this limited group are satisfactory. Stronger public policies are needed to guarantee optimal stroke treatment in patients on DOACs in Colombia.

Cierre de apéndice auricular en fibrilación auricular y alto riesgo de sangrado: serie de casos / Atrial appendage closure in atrial fibrillation and high risk of bleeding: case series

RESUMEN INTRODUCCIÓN: La fibrilación auricular aumenta 5 veces el riesgo de un ataque cerebrovascular de origen cardioembólico. La anticoagulación está indicada para prevención primaria y secundaria de embolismo cerebral. En pacientes con alto riesgo de sangrado no modificable se ha propuesto el cierre de apéndice auricular izquierdo como alternativa a la anticoagulación. MÉTODOS: Serie de casos retrospectiva de pacientes incluidos en el registro ReACTIVE entre los años 2019 y 2020 con diagnóstico de fibrilación auricular, puntaje de CHA2DS2-VASc ≥ 4, HAS BLED ≥ 3 y contraindicación de terapia anticoagulante a largo plazo. Se incluyeron variables demográficas, factores de riesgo, desenlace clínico usando la escala de Rankin modificado y se hizo seguimiento clínico a 3 meses después del procedimiento. RESULTADOS: Se incluyeron 6 pacientes, el 50 % de ellos mujeres, con mediana de edad de 80,8 ± 4,8 años. El 83,3 % presentó antecedente de sangrado mayor bajo consumo de anticoagulantes. En el seguimiento a 90 días, ningún paciente experimentó sangrado ni ataque cerebrovascular, un paciente murió por causas no cardiovasculares, en tanto que el 83,3 % de los pacientes tuvieron un Rankin modificado favorable (0-2). CONCLUSIONES: El cierre de apéndice auricular es una opción terapéutica en pacientes con fibrilación auricular y contraindicación para anticoagulación por alto riesgo de sangrado. Nuestra serie obtuvo resultados similares a los publicados a escala nacional a pesar de incluir pacientes con edad más avanzada. La conformación de equipos interdisciplinarios de corazón y cerebro es útil en la selección de pacientes para esta terapia.

ABSTRACT INTRODUCTION: Atrial fibrillation increases the risk of a cerebrovascular attack of cardioembolic source by 5 times. Anticoagulation is indicated for primary and secondary prevention of cerebral embolism. In patients at high risk of non-modifiable bleeding, closure of the left atrial appendage has been proposed as an alternative to anticoagulation. METHODS: Retrospective case series of patients included in the ReACTIVE registry between 2019 and 2020 with a diagnosis of atrial fibrillation, CHA2DS2-VASc score ≥ 4, HAS-BLED ≥ 3, and long-term anticoagulant therapy contraindication. Demographic variables, risk factors, and clinical outcomes were included using the modified Rankin scale, and clinical follow-up was done three months after the procedure. RESULTS: 6 patients were included, 50 % women, median age 80.8 ± 4.8 years. 83.3 % history of major bleeding under anticoagulant treatment. At the 90-day follow-up, no patient had a bleeding or cerebrovascular attack, one patient died from non-cardiovascular causes, and 83.3 % of the patients had a favorable modified Rankin (0-2). CONCLUSIONS: Atrial appendix closure is a therapeutic option in patients with atrial fibrillation and a contraindication for anticoagulation due to a high risk of bleeding. Our series obtained results like those published at the national level despite including older patients. The formation of interdisciplinary heart and brain teams is helpful in the selection of patients for this therapy.

Disparities Influencing Functional Outcomes Between Rural and Urban Patients With Acute Stroke.

Introduction: There is scarce information in Latin America about factors related to stroke patient outcomes in rural areas compared to urban ones. Objective: To evaluate functional outcomes of stroke code patients from rural and urban areas and their relationship with socioeconomic disparity. Methods: Prospective cohort study included patients of urban, semi-urban, and rural origin with stroke code from a high complexity hospital in southwestern Colombia between 2018 and 2019. Demographic, clinical data modified Rankin at discharge, and 3-month follow-up were analyzed. The poverty index, barriers to health access and availability of ambulances by the municipality was assessed at an ecological level. Results: Five hundred and fifty five stroke patients were registered, 21.2% from rural areas, 432 (77.98%) had an ischemic stroke. There were no significant differences in sociodemographic factors and medical background. Urban patients had lower reperfusion therapies rates (23.25%). Favorable mRS at discharge (<3) was higher in urban areas (63.03%) and mortality was superior in rural patients (13.56%). The ambulance rate in semi-urban and rural areas was as low as 0.03 per 100.000 inhabitants, the poverty index was 11.9% in urban areas vs. 23.3% in semi urban and rural areas. Conclusions: Rural patients treated in our center were more likely to present with severe strokes and unfavorable mRS at hospital discharge and 3-month follow-up compared to urban, despite having similar risk factors. There is an inverse relationship, which is not related to the poverty rate or the percentage of people with barriers to access to health. There is a need for further studies that assess barriers inherent in rural patients and establish a regional stroke network.

Did COVID-19 impact stroke services? A multicenter study.

BACKGROUND: It has been reported that acute stroke services were compromised during COVID-19 due to various pandemic-related issues. We aimed to investigate these changes by recruiting centers from different countries. METHODS: Eight countries participated in this cross-sectional, observational, retrospective study by providing data from their stroke data base. We compared 1 year before to 1 year during COVID-19 as regards onset to door (OTD), door to needle (DTN), door to groin (DTG), duration of hospital stay, National Institute of Health Stroke Scale (NIHSS) at baseline, 24 h, and at discharge as well as modified Rankin score (mRS) on discharge and at 3 months follow-up. RESULTS: During the pandemic year, there was a reduction in the number of patients, median age was significantly lower, admission NIHSS was higher, hemorrhagic stroke increased, and OTD and DTG showed no difference, while DTN time was longer, rtPA administration was decreased, thrombectomy was more frequent, and hospital stay was shorter. mRS was less favorable on discharge and at 3 months. CONCLUSION: COVID-19 showed variable effects on stroke services. Some were negatively impacted as the number of patients presenting to hospitals, DTN time, and stroke outcome, while others were marginally affected as the type of management.

Regional and national differences in stroke thrombolysis use and disparities in pricing, treatment availability, and coverage.

BACKGROUND: Major disparities have been reported in recombinant tissue plasminogen activator (rtPA) availability among countries of different socioeconomic status. AIMS: To characterize variability of rtPA price, its availability, and its association with and impact on each country's health expenditure (HE) resources. METHODS: We conducted a global survey to obtain information on rtPA price (50 mg vial, 2020 US Dollars) and availability. Country-specific data, including low, lower middle (LMIC), upper middle (UMIC), and high-income country (HIC) classifications, and gross domestic product (GDP) and HE, both nominally and adjusted for purchasing power parity (PPP), were obtained from World Bank Open Data. To assess the impact of rtPA cost, we computed the rtPA price as percentage of per capita GDP and HE and examined its association with the country income classification. RESULTS: rtPA is approved and available in 109 countries. We received surveys from 59 countries: 27 (46%) HIC, 20 (34%) UMIC, and 12 (20%) LMIC. Although HIC have significantly higher per capita GDP and HE compared to UMIC and LMIC (p < 0.0001), the median price of rtPA is non-significantly higher in LMICs (USD 755, interquartile range, IQR (575-1300)) compared to UMICs (USD 544, IQR (400-815)) and HICs (USD 600, IQR (526-1000)). In LMIC, rtPA cost accounts for 217.4% (IQR, 27.1-340.6%) of PPP-adjusted per capita HE, compared to 17.6% (IQR (11.2-28.7%), p < 0.0001) for HICs. CONCLUSION: We documented significant variability in rtPA availability and price among countries. Relative costs are higher in lower income countries, exceeding the available HE. Concerted efforts to improve rtPA affordability in low-income settings are necessary.

Fighting Against Stroke in Latin America: A Joint Effort of Medical Professional Societies and Governments.

Introduction: Stroke is one of the leading causes of death in Latin America, a region with countless gaps to be addressed to decrease its burden. In 2018, at the first Latin American Stroke Ministerial Meeting, stroke physician and healthcare manager representatives from 13 countries signed the Declaration of Gramado with the priorities to improve the region, with the commitment to implement all evidence-based strategies for stroke care. The second meeting in March 2020 reviewed the achievements in 2 years and discussed new objectives. This paper will review the 2-year advances and future plans of the Latin American alliance for stroke. Method: In March 2020, a survey based on the Declaration of Gramado items was sent to the neurologists participants of the Stroke Ministerial Meetings. The results were confirmed with representatives of the Ministries of Health and leaders from the countries at the second Latin American Stroke Ministerial Meeting. Results: In 2 years, public stroke awareness initiatives increased from 25 to 75% of countries. All countries have started programs to encourage physical activity, and there has been an increase in the number of countries that implement, at least partially, strategies to identify and treat hypertension, diabetes, and lifestyle risk factors. Programs to identify and treat dyslipidemia and atrial fibrillation still remained poor. The number of stroke centers increased from 322 to 448, all of them providing intravenous thrombolysis, with an increase in countries with stroke units. All countries have mechanical thrombectomy, but mostly restricted to a few private hospitals. Pre-hospital organization remains limited. The utilization of telemedicine has increased but is restricted to a few hospitals and is not widely available throughout the country. Patients have late, if any, access to rehabilitation after hospital discharge. Conclusion: The initiative to collaborate, exchange experiences, and unite societies and governments to improve stroke care in Latin America has yielded good results. Important advances have been made in the region in terms of increasing the number of acute stroke care services, implementing reperfusion treatments and creating programs for the detection and treatment of risk factors. We hope that this approach can reduce inequalities in stroke care in Latin America and serves as a model for other under-resourced environments.

COVID-19 Lockdown Effects on Acute Stroke Care in Latin America.

OBJECTIVES: COVID-19 pandemic has forced important changes in health care worldwide. Stroke care networks have been affected, especially during peak periods. We assessed the impact of the pandemic and lockdowns in stroke admissions and care in Latin America. MATERIALS AND METHODS: A multinational study (7 countries, 18 centers) of patients admitted during the pandemic outbreak (March-June 2020). Comparisons were made with the same period in 2019. Numbers of cases, stroke etiology and severity, acute care and hospitalization outcomes were assessed. RESULTS: Most countries reported mild decreases in stroke admissions compared to the same period of 2019 (1187 vs. 1166, p = 0.03). Among stroke subtypes, there was a reduction in ischemic strokes (IS) admissions (78.3% vs. 73.9%, p = 0.01) compared with 2019, especially in IS with NIHSS 0-5 (50.1% vs. 44.9%, p = 0.03). A substantial increase in the proportion of stroke admissions beyond 48 h from symptoms onset was observed (13.8% vs. 20.5%, p < 0.001). Nevertheless, no differences in total reperfusion treatment rates were observed, with similar door-to-needle, door-to-CT, and door-to-groin times in both periods. Other stroke outcomes, as all-type mortality during hospitalization (4.9% vs. 9.7%, p < 0.001), length of stay (IQR 1-5 days vs. 0-9 days, p < 0.001), and likelihood to be discharged home (91.6% vs. 83.0%, p < 0.001), were compromised during COVID-19 lockdown period. CONCLUSIONS: In this Latin America survey, there was a mild decrease in admissions of IS during the COVID-19 lockdown period, with a significant delay in time to consultations and worse hospitalization outcomes.

Recomendaciones y consideraciones del Comité Vascular de la Asociación Colombiana de Neurología para el manejo del ataque cerebrovascular isquémico durante la pandemia por covid-19 / Considerations and recommendations from the Stroke Committee of the Colombian Neurological Association for the management of Acute Ischemic Stroke during the pandemic for COVID-19

RESUMEN PROPÓSITO: En marzo 11 del 2020 la Organización Mundial de la Salud declara la pandemia por Covid-19. El clínico se va enfrentar a pacientes con ataque cerebrovascular (ACV) y sospecha o presencia de la infección. Miembros participantes del comité vascular de la Asociación Colombiana de Neurología basados en la experticia y la literatura amplían las primeras recomendaciones en el manejo de los pacientes con ACV isquémico agudo durante la actual pandemia. MÉTODOS: Mediante reuniones virtuales y por consenso de los participantes se escogieron tres ejes de trabajo: Tamización para Covid-19, Medidas de bioseguridad y Aspectos relevantes del ACV isquémico en época de pandemia por Covid-19. Se desarrollaron los ejes por grupos de trabajo mediante la modalidad de pregunta-respuesta pretendiendo generar en cada una de ellas recomendaciones sobre el tema. La versión final del documento conto con la revisión y el aval de todos los participantes. RESULTADOS: El documento cuenta con tres secciones correspondientes a los ejes de trabajo. En el primer eje se responden 3 preguntas y se dan recomendaciones sobre la tamización de la infección por Covid-19 en ACV agudo. En el segundo se responden 8 preguntas y se dan recomendaciones sobre las medidas de bioseguridad en la atención de pacientes con ACV durante la pandemia. En el tercero se tratan 13 aspectos relevantes del ACV durante la pandemia, según criterio de los participantes, y se dan recomendaciones pertinentes. CONCLUSIÓN: Las recomendaciones son basadas en la literatura y consenso de los participantes para el cuidado de pacientes con ACV isquémico agudo con sospecha o infección por Covid-19. No pretenden reemplazar las guías o protocolos establecidos sino ampliar las primeras recomendaciones del comité y apoyar al clínico en la atención de pacientes con ACV isquémico durante la pandemia.

SUMMARY PURPOSE: The World Health Organization declared the COVID-19 pandemic on March 11th 2020. Clinicians will face patients with stroke and confirmed or suspected infection. Members of the Stroke Committee of the Colombian Neurological Association based on their expertise and literature review extend on the first recommendations on acute ischemic stroke management during the pandemic. METHODS: Through virtual meetings and by consensus of participants three topics were selected: COVID-19 screening, biosafety measures and relevant aspects of acute ischemic stroke care during the pandemic. A question and answer format was used to develop recommendations for each topic. RESULTS: The manuscript is divided into three sections. The first includes three questions and recommendations on screening for COVID-19 in stroke patients. The second includes 8 questions and recommendations on biosafety measures on stroke patients during the pandemic. The last section includes 13 relevant stroke topics during COVID-19 pandemic, as deemed by the authors, and their recommendations. CONCLUSIONS: Recommendations on stroke care and COVID-19 are based on literature review and expert consensus. The aim of the manuscript is to extend on the first recommendations forwarded by the Committee, not to replace current guidelines, and to support the clinician caring for stroke patients during the pandemic.

Recomendaciones de diagnóstico y tratamiento del ataque cerebrovascular isquémico agudo durante la contingencia por covid-19 / Recommendations for diagnosis and treatment of the acute ischemic stroke during COVID-19 contingency

RESUMEN INTRODUCCIÓN. El tiempo es un factor importante en el tratamiento del ACV agudo, con la pandemia de covid-19 se puede ver afectada la adherencia a las guías. Se han reportado tasas de ACV en presencia de covid-19 alrededor del 5%, además un aumento en el tiempo de consulta de los pacientes en otras regiones del mundo y una mayor ocupación de camas de UCI para patologías respiratorias que usualmente se destinan a pacientes con ACV. Este documento recoge las recomendaciones del comité de Enfermedad Cerebrovascular de la Asociación Colombiana de Neurología basados en la literatura y votadas por consenso. OBJETIVOS. Proporcionar una guía rápida adaptada a los diferentes escenarios de atención de ACV en Colombia, divididos en centro listo, primario y avanzado incluyendo una ruta de atención para paciente con sospecha de covid-19 denominada Código ACV protegido, que incluye el uso de elementos de protección personal para pacientes y personal de salud. PUNTOS PRINCIPALES. Dentro de las recomendaciones principales está el cuestionario de tamizaje al ingreso a urgencias, uso de tapabocas para el paciente, considerar todo Código ACV sospechoso de covid-19, toma de PCR para covid-19 en todos los ACV y llevar a zona buffer. En sospecha de oclusión proximal incluir tomo-grafía de tórax a la evaluación de imágenes. CONCLUSIONES. Establecer pautas de atención durante la pandemia covid-19 permite optimizar protección para pacientes y personal de salud, disminuir retrasos y tratar de evitar que pacientes no reciban el tratamiento adecuado en los diferentes niveles de atención del sistema de salud.

SUMMARY INTRODUCTION. Time is an important factor in the treatment of acute stroke, with the COVID-19 pandemic adherence to guidelines can be affected. Stroke rates in the presence of COVID-19 have been reported around 5%, in addition to an increase in the consultation time of patients in other regions of the world and a greater occupation of ICU beds for respiratory pathologies that are usually intended for patients with stroke. This document contains the recommendations of the Cerebrovascular Disease Committee of the Colombian Neurology Association based on the literature and voted by consensus. OBJECTIVES. Provide a quick guide adapted to the different stroke care scenarios in Colombia, divided into ready, primary and advanced centers, including a care route for a patient with suspected COVID-19 called the protected stroke code, which includes the use of protection elements for the patient and the healthcare team. MAIN FACTS. Among the main recommendations are the screening questionnaire on admission to the emergency department, the use of face masks for the patient, considering all suspected stroke code as COVID-19, taking the PCR for COVID-19 in all strokes and taking them to the buffer zone. In suspected large vessel occlusion, include chest tomography to image evaluation. CONCLUSIONS. Establishing guidelines of care during the COVID-19 pandemic allows optimizing protection for patients and health care personnel, reducing delays and trying to avoid patients not receiving adequate treatment at different levels of attention in the health system.

Sex Differences Among Participants in the Latin American Stroke Registry.

Background Reports on sex differences in stroke outcome and risk factors are scarce in Latin America. Our objective was to analyze clinical and prognostic differences according to sex among participants in the LASE (Latin American Stroke Registry). Methods and Results Nineteen centers across Central and South America compiled data on demographics, vascular risk factors, clinical stroke description, ancillary tests, and functional outcomes at short-term follow-up of patients included from January 2012 to January 2017. For the present study, all these variables were analyzed according to sex at hospital discharge. We included 4788 patients with a median in-hospital stay of 8 days (interquartile range, 5-8); 2677 were male (median age, 66 years) and 2111 female (median age, 60 years). Ischemic stroke occurred in 4293: 3686 as cerebral infarction (77%) and 607 as transient ischemic attack cases (12.7%); 495 patients (10.3%) corresponded to intracerebral hemorrhage. Poor functional outcome (modified Rankin scale, 3-6) was present in 1662 (34.7%) patients and 38.2% of women (P<0.001). Mortality was present in 6.8% of the registry, with 7.8% in women compared with 6.0% in men (P=0.01). Death and poor functional outcome for all-type stroke showed a higher risk in female patients (hazard ratio, 1.3, P=0.03; and hazard ratio, 1.1, P=0.001, respectively). Conclusions A worse functional outcome and higher mortality rates occurred in women compared with men in the LASE, confirming sex differences issues at short-term follow-up.

Edema agudo de pulmón por presión negativa secundario a laringoespasmo / Acute lung edema due to negative pressure secondary to laryngospasm

Resumen El edema agudo de pulmón por presión negativa es una forma de edema pulmonar no cardiogénico, potencialmente grave, que suele ocurrir en sujetos sanos jóvenes capaces de generar presiones intratorácicas negativas elevadas al inspirar vigorosamente contra una vía aérea superior obstruida. En adultos la causa más frecuente es el laringoespasmo posextubación en el periodo posoperatorio inmediato. Puede afectar a 0.05-0.1% de los pacientes sanos sometidos a anestesia general. Se comunica el caso de un paciente de 24 años de edad, sin antecedentes patológicos, que acudió al servicio de consulta externa de Cirugía del Hospital Regional Santa Teresa, Comayagua, Honduras, para realizar colecistectomía abierta por colecistitis crónica calculosa agudizada. Se realizó procedimiento quirúrgico sin complicaciones; 15 minutos del periodo posoperatorio inmediato, después de la extubación, el paciente tuvo cuadro clínico de disnea súbita, cianosis y hemoptisis. A la exploración física se encontró hipoxemia, taquipnea (FR = 40 rpm) y crépitos bilaterales en la auscultación. Se realizaron exámenes complementarios y de imagen, concluyendo edema agudo de pulmón. Se inició tratamiento con oxigenoterapia, corticoesteroides y diuréticos durante 72 horas, con lo que evolucionó de forma favorable. Los hallazgos clínicos del edema agudo de pulmón por presión negativa pueden confundirse con una amplia gama de afecciones clínicas, por lo que es de suma importancia realizar el abordaje adecuado y diagnóstico diferencial. El inicio de las medidas terapéuticas oportunas ofrece un pronóstico favorable y generalmente disminución de la mortalidad.

Abstract Acute negative pressure pulmonary edema is a form of potentially serious noncardiogenic pulmonary edema that usually occurs in young healthy subjects capable of generating elevated negative intrathoracic pressures by vigorously inhaling a blocked upper airway. In adults, the most frequent cause is postextubation laryngospasm in the immediate postoperative period. It can present in 0.05-0.1% of healthy patients under general anesthesia. This paper reports the case of a 24-year-old male with no pathological history, who was presented to the general surgery service of the Hospital Regional Santa Teresa, Comayagua, Honduras, to perform open cholecystectomy for chronic cholecystitis. The surgical procedure was performed without complications; 15 minutes of the immediate postoperative period, post-extubation, patient presented clinical manifestations of sudden dyspnea, cyanosis and hemoptysis. On physical examination were found hypoxemia, tachypnea (BR = 40 bfm) and bilateral craniocereus on pulmonary auscultation. Complementary tests and image were performed and NPPE was diagnosed. Treatment with oxygen therapy, corticosteroids and diuretics was started, during 72 hours evolving favorably. The clinical findings of the acute negative pressure pulmonary edema can be confused with a wide range of clinical entities, so it is extremely important to carry out an adequate approach and differential diagnosis. The introduction of appropriate therapeutic measures offers a favorable prognosis and generally a wide decrease in mortality.

Identification of siRNA delivery enhancers by a chemical library screen.

Most delivery systems for small interfering RNA therapeutics depend on endocytosis and release from endo-lysosomal compartments. One approach to improve delivery is to identify small molecules enhancing these steps. It is unclear to what extent such enhancers can be universally applied to different delivery systems and cell types. Here, we performed a compound library screen on two well-established siRNA delivery systems, lipid nanoparticles and cholesterol conjugated-siRNAs. We identified fifty-one enhancers improving gene silencing 2-5 fold. Strikingly, most enhancers displayed specificity for one delivery system only. By a combination of quantitative fluorescence and electron microscopy we found that the enhancers substantially differed in their mechanism of action, increasing either endocytic uptake or release of siRNAs from endosomes. Furthermore, they acted either on the delivery system itself or the cell, by modulating the endocytic system via distinct mechanisms. Interestingly, several compounds displayed activity on different cell types. As proof of principle, we showed that one compound enhanced siRNA delivery in primary endothelial cells in vitro and in the endocardium in the mouse heart. This study suggests that a pharmacological approach can improve the delivery of siRNAs in a system-specific fashion, by exploiting distinct mechanisms and acting upon multiple cell types.

Estudio comparativo de la actividad antimicrobiana de diferentes presentaciones comerciales de antibióticos de administración intravenosa a través de métodos in vitro / Comparative study of the antimicrobial activity of several marketed antibiotic drugs for intravenous administration by in vitro methods

En este trabajo, se desarrollaron bioensayos para la valoración de ceftriaxona, cefotaxima, ceftazidima, ampicilina/sulbactam e imipenem/cilastatina. Se pudo establecer un único microorganismo (esporas de Bacillus subtilis ATCC 6633) para la ejecución del bioensayo. El rango de concentración que tiene la mejor correlación dosis-respuesta es propio de cada antibiótico, al igual que las condiciones del ensayo (pH de la solución de antibiótico, pH de medio de cultivo, tiempo de incubación). Con los bioensayos validados se hizo un estudio de comparación de muestras de productos innovadores, genéricos de marca y genéricos, que dio como resultado que presentan la misma actividad antimicrobiana in vitro, además de confirmar que son equivalentes farmacéuticos