Ice sheet-free West Antarctica during peak early Oligocene glaciation.

One of Earth's most fundamental climate shifts, the greenhouse-icehouse transition 34 million years ago, initiated Antarctic ice sheet buildup, influencing global climate until today. However, the extent of the ice sheet during the Early Oligocene Glacial Maximum (~33.7 to 33.2 million years ago) that immediately followed this transition-a critical knowledge gap for assessing feedbacks between permanently glaciated areas and early Cenozoic global climate reorganization-is uncertain. In this work, we present shallow-marine drilling data constraining earliest Oligocene environmental conditions on West Antarctica's Pacific margin-a key region for understanding Antarctic ice sheet evolution. These data indicate a cool-temperate environment with mild ocean and air temperatures that prevented West Antarctic Ice Sheet formation. Climate-ice sheet modeling corroborates a highly asymmetric Antarctic ice sheet, thereby revealing its differential regional response to past and future climatic change.

The RIPASA score for the diagnosis of acute appendicitis: A comparison with the modified Alvarado score. / Escala RIPASA para el diagnóstico de apendicitis aguda: comparación con la escala de Alvarado modificada.

INTRODUCTION AND OBJECTIVES: Acute appendicitis is the first cause of surgical emergencies. It is still a difficult diagnosis to make, especially in young persons, the elderly, and in reproductive-age women, in whom a series of inflammatory conditions can have signs and symptoms similar to those of acute appendicitis. Different scoring systems have been created to increase diagnostic accuracy, and they are inexpensive, noninvasive, and easy to use and reproduce. The modified Alvarado score is probably the most widely used and accepted in emergency services worldwide. On the other hand, the RIPASA score was formulated in 2010 and has greater sensitivity and specificity. There are very few studies conducted in Mexico that compare the different scoring systems for appendicitis. The aim of our article was to compare the modified Alvarado score and the RIPASA score in the diagnosis of patients with abdominal pain and suspected acute appendicitis. MATERIAL AND METHODS: An observational, analytic, and prolective study was conducted within the time frame of July 2002 and February 2014 at the Hospital Universitario de Puebla. The questionnaires used for the evaluation process were applied to the patients suspected of having appendicitis. RESULTS: The RIPASA score with 8.5 as the optimal cutoff value: ROC curve (area .595), sensitivity (93.3%), specificity (8.3%), PPV (91.8%), NPV (10.1%). Modified Alvarado score with 6 as the optimal cutoff value: ROC curve (area .719), sensitivity (75%), specificity (41.6%), PPV (93.7%), NPV (12.5%). CONCLUSIONS: The RIPASA score showed no advantages over the modified Alvarado score when applied to patients presenting with suspected acute appendicitis.

Endosonografía con biopsia por aspiración con aguja fina de glándula suprarrenal izquierda para el diagnóstico de paracoccidioidomicosis: aporte de un nuevo caso a la literatura / Endosonography with Fine Needle Aspiration Biopsy of the Left Adrenal Gland for Diagnosis of Paracoccidioidomycosis: Contribution of a New Case to the Literature

Resumen La endosonografía nació hace más de 30 años como parte de las modalidades diagnósticas de patologías benignas y malignas del tracto gastrointestinal. En los últimos años se ha demostrado la eficacia y seguridad superior de la biopsia con aguja fina de las glándulas suprarrenales por vía transgástrica (izquierda) o tranduodenal (derecha) guiadas por endosonografía, en comparación con los abordajes percutáneos guiados por tomografía axial computarizada (TAC) o ecografía. Uno de los diagnósticos diferenciales de insuficiencia suprarrenal con evidencia de masas en glándulas suprarrenales es la paracoccidioidomicosis, a pesar de ser una entidad de presentación exclusiva de las áreas geográficas de Latinoamérica, donde se encuentra su agente etiológico. Se presenta un caso de paciente con paracoccidioidomicosis con insuficiencia suprarrenal y engrosamiento adrenal bilateral, cuyo diagnóstico se logró mediante biopsia transgástrica de glándula suprarrenal izquierda guiada por endosonografía.

Abstract Endosonography, born more than 30 years ago, is one diagnostic modality for benign and malignant pathologies of the gastrointestinal tract. In recent years, transgastric (left) or transduodenal (right) fine needle biopsies of the adrenal glands guided by endosonography has been demonstrated to be safer and more efficacious than percutaneous approaches guided by CT or ultrasound. Differential diagnoses of adrenal insufficiency with evidence of masses in adrenal glands must consider paracoccidioidomycosis despite the fact that it is exclusively present in Latin America where its etiological agent is found. We present a case of paracoccidioidomycosis with adrenal insufficiency and bilateral adrenal thickening whose diagnosis was achieved by transgastric biopsy of the left adrenal gland guided by endosonography.

Terapia de rescate en perforación de vía biliar con stent metálico autoexpandible totalmente cubierto posterior a falla en el manejo conservador: reporte de un caso / Case Report of Rescue Therapy for Bile Duct Perforation using Fully Covered Self-Expanding Metal Stent after Failure of Conservative Management

Resumen Las complicaciones de la colangiopancreatografía retrógrada endoscópica (CPRE) ocurren entre el 5% y 10% de los pacientes, de los cuales menos del 1% sufre perforaciones. El uso de stents metálicos autoexpandibles totalmente cubiertos para el cierre de perforaciones no complicadas se ha convertido en una estrategia opcional y segura para el manejo inicial de estos pacientes, así como una terapia de rescate para quienes el manejo conservativo ha fallado. Presentamos el caso de una paciente de 73 años con coledocolitiasis residual que fue sometida a una CPRE terapéutica con esfinterotomía y remoción de los cálculos. 12 horas después de la intervención, consultó al servicio de urgencias donde se confirmó una perforación de la vía biliar tipo II secundaria a esfinterotomía. Ulteriormente, se ofreció un manejo conservador con retiro de la ingesta oral, terapia con inhibidor de la bomba de protones, antibióticos, evaluación quirúrgica y observación médica. Sin embargo, ante la falla del manejo no quirúrgico, se consideró la colocación del stent metálico autoexpandible totalmente cubierto como terapia de rescate con evolución satisfactoria en el postoperatorio y salida 8 días después de la colocación del stent.

Abstract Complications occur in 5% to 10% of patients who undergo endoscopic retrograde cholangiopancreatography (ERCP), but less than 1% suffer perforations. The use of fully covered self-expanding metal stents (SEMS) to close uncomplicated perforations has become a safe optional strategy for initial management of these patients, as well as for rescue therapy when conservative management has failed. We present the case of a 73-year-old patient with residual choledocholithiasis who underwent therapeutic ERCP with sphincterotomy and stone removal. Twelve hours after the intervention, the patient returned to the emergency department where a biliary tract type II perforation secondary to sphincterotomy was confirmed. Subsequent conservative management included suspension of oral feeding, administration of proton pump inhibitors and antibiotics, surgical evaluation and medical observation. Failure of non-surgical management led to consideration of placement of a fully covered SEMS as rescue therapy. The patient's postoperative evolution was with satisfactory, and she was discharged eight days after stent placement.

Interobserver agreement on the echocardiographic parameters that estimate right ventricular systolic function in the early postoperative period of cardiac surgery. / Acuerdo interobservador de los parámetros ecocardiográficos que estiman la función sistólica del ventrículo derecho en el postoperatorio temprano de cirugía cardiaca.

PRIMARY OBJECTIVE: To know the variability of transthoracic echocardiographic parameters that assess right ventricular systolic function by analyzing interobserver agreement in the early postoperative period of cardiovascular surgery. SECONDARY OBJECTIVE: To assess the feasibility of these echocardiographic measurements. DESIGN: A cross-sectional study, double-blind pilot study was carried out from May 2011 to February 2013. SETTING: Cardiovascular postoperative critical care at the National Institute of Cardiology "Ignacio Chávez", Mexico City, Mexico. PATIENTS: Consecutive, non-probabilistic sampling. Fifty-six patients were studied in the postoperative period of cardiac surgery. INTERVENTION: The first echocardiographic parameters were obtained between 6-8hours after cardiac surgery, followed by blinded second measurements. MAIN VARIABLES: Tricuspid annular plane systolic excursion (TAPSE), tricuspid annular peak systolic velocity on tissue Doppler imaging (VSPAT), diameters and right ventricular outflow area, tract fractional shortening. The agreement was analyzed by the Bland-Altman method, and its magnitude was assessed by the intraclass correlation coefficient (95% confidence interval). RESULTS: Both observers evaluated TAPSE and VSPAT in 48 patients (92%). The average TAPSE was 11.68±4.53mm (range 4-27mm). Right ventricular systolic dysfunction was observed in 41 cases (85%) and normal TAPSE in 7 patients (15%). The average difference and its limits according to TAPSE were -0.917±2.95 (-6.821, 4.988), with a magnitude of 0.725 (0.552, 0.837); the tricuspid annular peak systolic velocity on tissue Doppler imaging was -0.001±0.015 (-0.031, 0.030), and its magnitude 0.825 (0.708, 0.898), respectively. CONCLUSIONS: VSPAT and TAPSE were estimated by both observers in 92% of the patients, these parameters exhibiting the lowest interobserver variability.

The environmental disaster of Aznalcóllar (southern Spain) as an approach to the Cretaceous-Palaeogene mass extinction event.

Biotic recovery after the Cretaceous-Palaeogene (K-Pg) impact is one unsolved question concerning this mass extinction event. To evaluate the incidence of the K-Pg event on biota, and the subsequent recovery, a recent environmental disaster has been analysed. Areas affected by the contamination disaster of Aználcollar (province of Sevilla, southern Spain) in April 1998 were studied and compared with the K-Pg event. Several similarities (the sudden impact, the high levels of toxic components, especially in the upper thin lamina and the incidence on biota) and differences (the time of recovery and the geographical extension) are recognized. An in-depth geochemical analysis of the soils reveals their acidity (between 1.83 and 2.11) and the high concentration of pollutant elements, locally higher than in the K-Pg boundary layer: values up to 7.0 mg kg(-1) for Hg, 2030.7 mg kg(-1) for As, 8629.0 mg kg(-1) for Pb, 86.8 mg kg(-1) for Tl, 1040.7 mg kg(-1) for Sb and 93.3-492.7 p.p.b. for Ir. However, less than 10 years after the phenomenon, a rapid initial recovery in biota colonizing the contaminated, 'unfavourable', substrate is registered. Nesting of the ant Tapinoma nigerrima (Nylander) has taken place through the tailing layer, with arranged particles from inside the soils showing similar values in pollutant elements as the deep soils. This agrees with recent ichnological evidence of a rapid colonization of the K-Pg boundary layer, classically interpreted as an inhabitable substrate, by organisms with a high independence with respect to substrate features (i.e. Chondrites trace makers). The dramatic consequences of the K-Pg boundary impact and the generalized long-time recovery interpreted after the event (in the order of 10(4)-10(5) years) could have been overestimated due to the absence of a high-temporal resolution in the range of 10(2)-10(3) years.

Hydrodynamic effects of the partial opening of a trileaflet valve.

Manufacturing process of medical grade silicon rubber trileaflet valves for VADs could propitiate important leaflet thickness variations which could result in partial opening of the valve and affect its hydrodynamic performance. The leaflets of a total of 10 valves were measured to assess its thickness variability. Two experiments were performed to asses the impact of the leaflets thickness variation under hypothetical situations. The first experiment was divided into three hypothetical cases. In each case either none, one or two leaflets of different valves were mechanically blocked, resembling possible critical working circumstances. The second experiment was intended to know how the variation on the leaflets thickness affects the hydrodynamic performance of the valves. The results demonstrated a significant variation on the leaflets thickness was found. As for the first experiment, a small variation on the hydrodynamic performance was found above 4 L/min flow rates and a slightly higher energy loss was found in one of the cases. As for the second experiment, the results showed that the variation of the leaflet thickness does not affect the general hydrodynamic performance of the valves. No relationship between the thickness variability and the hydrostatic performance of the valves was found.

Structural performance and hydrodynamic resistance of a new silicone auricular cannula tip.

Development of a new generation pneumatic of Ventricular Assist Device (VAD) required the design of cannulae to improve its optimal performance. In this case, a relevant restrictive design parameter was the material of the cannulae. Silicone was the best choice in a hemocompatible focus, but this is a material with very low stiffness. If the material is flexible, the most important parameter that affects either the structural performance or the hydrodynamic resistance is the amount of side holes on the cannulae tip, known as the effective drainage area. In order to obtain an estimation of the structural performance and of the hydrodynamic resistance, a study based on two independent analysis is needed: the structural and the in vitro drop pressure analysis. Structural analyses based on computer simulations were made in order to estimate the bending behavior of four silicone prototypes of cannulae tips. On the other hand, experiments under hydrostatic conditions were made to test and compare the pressure loss and flow rate relationship. A cannula tip with six side holes showed good hydrostatic performance, having almost the same as the one with nine side holes. Plus, it presented and a satisfactory structural behavior. This study assisted the design process of an auricular silicone cannula, recommending the use of cannulae with six side holes for a specific VAD.

Experimental and Computer-Based Performance Analysis of Two Elastomer VAD Valve Designs.

The development of a new generation pneumatic Ventricular Assist Device (VAD) required the design of valves for the optimization of its performance. Experiments and computer-based simulations under hydrostatic conditions were analyzed in order to test and compare two low-cost elastomer valve designs. The trileaflet valve design showed a superior hydrostatic performance, having almost a ratio of 1:2 hydraulic resistance than the bileaflet valve design in agreement with both, the experimental and the simulation evidences. This study will address the use of a trileaflet valve designs in the future VAD redesign.