A numerical-experimental protocol to characterize corneal tissue with an application to predict astigmatic keratotomy surgery.

Tonometers are intended to determine the intraocular pressure (IOP) and the quality of corneal tissue. In contrast to the physiological state of stress of the cornea, tonometers induce non-physiological bending stress. Recently, the use of a single experiment to calibrate a set of corneal mechanical properties was suggested to be an ill-posed problem. Thus, we propose a numerical-experimental protocol that uses inflation and indentation experiments simultaneously, restricting the optimization space to circumvent the ambiguity of the fitting. For the first time, both corneal behaviors, i.e., biaxial tension (physiological) and bending (non-physiological), are taken into account. The experimental protocol was performed using an animal model (New Zealand rabbit's cornea). The patient-specific geometry and IOP were registered using a MODI topographer (CSO, Italy) and an applanation tonometer, respectively. The mechanical response was evaluated using inflation and indentation experiments. Subsequently, the optimal set of material properties is identified via an inverse finite element method. To validate the methodology, an in vivo incisional refractive surgery (astigmatic keratotomy, AK) is performed on four animals. The optical outcomes showed a good agreement between the real and simulated surgeries, indicating that the protocol can provide a reliable set of mechanical properties that enables further applications and simulations. After a reliable ex vivo database of inflation experiments is built, our protocol could be extended to humans.

Survival Outcomes in Liver Transplantation With Elderly Donors: Analysis of Andalusian Transplant Register.

Recently, there has been a large discrepancy between the number of patients on the waiting list for a liver transplant and the availability of deceased donors, with an increase in annual wait list mortality rates. Elderly donor livers are thought to be marginal grafts; however, in recent years, their utilization has constantly increased. The aim of this study is to evaluate the utilization of elderly donors in Andalusia and post-transplant outcomes. This retrospective observational study of 2408 liver transplants, performed in Andalusia between 2000 and 2014, analyzes the outcomes from donors aged 70 plus (n = 423) in terms of survival rates of the graft and the recipient, the type of transplant, donor age, and D-MELD score (product of donor age and preoperative Model for End-stage Liver Disease score). The most frequent indications for transplant were alcoholic cirrhosis (49.2%), hepatitis C cirrhosis (13%), and hepatocellular carcinoma (12.5%). The overall survival at 5 years was 64%, with a significant fall in survival for recipients with a D-MELD greater than 1500 (57%; P = .045). In the 70-year-old-plus donor group, the overall patient survival was 58.4%. The retransplant rate increased proportionately with donor age. In the alcoholic cirrhosis recipient subgroup, the overall survival at 5 years was 67.6% (P < .05) compared with 33.5% in patients with hepatitis C. Use of elderly donors is a safe strategy to reduce the scarcity of donors, provided that a D-MELD score below 1500 is obtained. Retransplant rates increase progressively with donor age. It is necessary to carefully screen recipients of older organs, taking into account that the best results are obtained for alcoholic cirrhosis, negative viral load hepatitis C, and a D-MELD score below 1500.

Automatized Patient-Specific Methodology for Numerical Determination of Biomechanical Corneal Response.

This work presents a novel methodology for building a three-dimensional patient-specific eyeball model suitable for performing a fully automatic finite element (FE) analysis of the corneal biomechanics. The reconstruction algorithm fits and smooths the patient's corneal surfaces obtained in clinic with corneal topographers and creates an FE mesh for the simulation. The patient's corneal elevation and pachymetry data is kept where available, to account for all corneal geometric features (central corneal thickness-CCT and curvature). Subsequently, an iterative free-stress algorithm including a fiber's pull-back is applied to incorporate the pre-stress field to the model. A convergence analysis of the mesh and a sensitivity analysis of the parameters involved in the numerical response is also addressed to determine the most influential features of the FE model. As a final step, the methodology is applied on the simulation of a general non-commercial non-contact tonometry diagnostic test over a large set of 130 patients-53 healthy, 63 keratoconic (KTC) and 14 post-LASIK surgery eyes. Results show the influence of the CCT, intraocular pressure (IOP) and fibers (87%) on the numerical corneal displacement (U(Num)) the good agreement of the U(Num) with clinical results, and the importance of considering the corneal pre-stress in the FE analysis. The potential and flexibility of the methodology can help improve understanding of the eye biomechanics, to help to plan surgeries, or to interpret the results of new diagnosis tools (i.e., non-contact tonometers).

Cinemática fisiológica de rodilla en futbolistas amateur: análisis 3D / Physiological kinematics of the knee in amateur soccer players: a 3D analysis

La lesión del ligamento cruzado anterior (LCA) tiene un alta prevalencia en jugadores de fútbol. En esta disciplina, las carreras con cambios de dirección son frecuentes y pueden ser un factor de riesgo para el desarrollo de lesiones del LCA sin contacto. Objetivo: Describir en futbolistas jóvenes los rangos cinemáticos fisiológicos de rodilla sometida a tareas funcionales con cambios bruscos de dirección. Método: En una muestra de ocho futbolistas con rodillas clínicamente sanas, se evaluó, mediante un sistema de análisis de movimiento 3D, la cinemática de la rodilla de apoyo durante la ejecución de tres tareas funcionales, dos de estas implicaron cambios de dirección en 90° (CD90°) y 180° (CD180°), la tercera golpear un balón (GB). Los rangos fisiológicos de movimiento (ROM) fueron registrados y comparados en la misma rodilla en tres planos diferentes (T-Transversal; F-Frontal; S-Sagital). Resultados: Los rangos fisiológicos obtenidos fueron para las tareas funcionales CD90°: T 11°(13-8), F 5.6° (11-4) y S 22°(30-17); para CD180°: T 9°(12-8), F 6.3°(8-5) y S 17.6°(21-14); y para GB: T 9°(10-5), F 3.8°(10-2), y S 9.6°(15-6). El ROM fue significativamente mayor en el plano transversal para la tarea CD90°. El el plano sagital el ROM fue mayor para CD90° comparado con GB (p<.05), sin embargo no hubo diferencias respecto a la tarea CD180°. No existen diferencias del ROM en el plano frontal. Conclusión: Se logró describir los rangos cinemáticos fisiológicos de la rodilla durante la ejecución de tres tareas funcionales que implicaron cambios bruscos de dirección en futbolistas amateur. En la muestra evaluada, la prueba que produjo una mayor exigencia de los rangos articulares de rodilla en los planos transversal y sagital fue la prueba con cambio de dirección en 90°...

Anterior cruciate ligament (ACL) lesions are frequent among soccer players. In this sport cutting movements are usually made while running and may be a risk factor in developing non-contact ACL injuries. Purpose: To describe the physiological kinematics of the knee during sudden change of direction movements in amateur soccer players. Methods:Eight amateur soccer players without previous injuries were analysed. The kinematics of the support knee were evaluated using 3D motion analysis while executing 3 common manoeuvres: two of them involved a change of direction at 90° and 180° (CD90° and CD180°), and the third while kicking a ball (GB). Physiological articular ranges of motion (ROM) were recorded and compared for the same knee in three different planes (T-Transversal; F-Frontal; S-Sagittal). Results: The physiological ranges obtained were, for manouvre CD90°: T 11°(13-8), F 5.6° (11-4) and S 22°(30-17); for CD180°: T 9°(12-8), F 6.3°(8-5) and S 17.6°(21-14); and for GB: T 9°(10-5), F 3.8°(10-2), and S 9.6°(15-6). ROM was significantly greater in the transversal plane for the CD90° manoeuvre (P<.05). In the sagittal plane, ROM was greater for the CD90° when compared to the GB (P<.05), but no differences were seen when compared to the CD180° manoeuvre (P>.05). There were no differences in ROM in the frontal plane. Conclusion: A description of the physiological kinematic ranges of the knee during three sudden changes of direction manoeuvres in amateur soccer players was presented. According to our results, change of direction in 90° demands a higher range of motion in both the transversal and sagittal planes...

Gas-driven subharmonic waves in a vibrated two-phase granular material.

Vibrated powders exhibit striking phenomena: subharmonic waves, oscillons, convection, heaping, and even bubbling. We demonstrate novel rectangular profile subharmonic waves for vibrated granular material, that occur uniquely in the two-phase case of grains, and a fluid, such as air. These waves differ substantially from those for the gas-free case, exhibit different dispersion relations, and occur for specific shaking parameters and air pressure, understandable with gas-particle flow models. These waves occur when the gas diffusively penetrates the granular layer in a time comparable to the shaker period. As the pressure is lowered towards P =0, the granular-gas system exhibits a Knudsen regime. This instability provides an opportunity to quantitatively test models of two-phase flow.

Diagnostic yield and safety of capsule endoscopy.

INTRODUCTION: the capsule endoscopy (CE), from his approval, has become a first line diagnostic procedure for the study of the small bowel disease. The aim of this study is to report our experience since the implantation of this technique in our hospital. MATERIAL AND METHODS: retrospective review of the CE undertaken in Department of Endoscopy. There was gathered in every case the age, sex, motive of consultation, previous diagnostic procedures, capsule endoscopy findings and complication of the technique. One took to end a descriptive and analytical analysis. RESULTS: there was achieved a total of 416 explorations in 388 patients. The obscure gastrointestinal bleeding was the most frequent indication (83.30%) followed by suspected Crohn s disease (7.5%). Angiodisplasia was the endoscopic lesion more frequently detected (42.2%), especially, in patients with digestive bleeding of obscure origin (OR 3.13 p < 0.001), followed by the flebectasia (10.6%) and the ulcer suspicious of Crohn s disease (9.9%). The global diagnostic yield as for the detection of injuries was 77.34% with a case of "not defecation of the capsule" and therefore need of laparotomy. CONCLUSIONS: the capsule endoscopy is a technique consolidated and as his potential is known, his indications are extended. The obscure gastrointestinal bleeding is the most frequent indication and the angiodisplasia the most identified injury. Once known his diagnostic yield, larger studies are needed that assess the influence of capsule endoscopy on clinical outcoumes.

Rendimiento diagnóstico seguridad de la cápsula endoscópica / Diagnostic yield and safety of capsule endoscopy

Introducción: la cápsula endoscópica desde su aprobación seha convertido en un procedimiento diagnóstico de primera líneapara el estudio del intestino delgado. El objetivo del estudio es exponerla experiencia desde la implantación de esta técnica ennuestro hospital.Material y métodos: se hizo una revisión retrospectiva de losestudios realizados en el Servicio de Endoscopia. Se recogió encada caso la edad, sexo, motivo de consulta, procedimientos diagnósticosprevios, diagnósticos endoscópicos e incidencias inherentesa la técnica y se llevó a cabo un análisis descriptivo y analítico.Resultados: se realizaron un total de 416 exploraciones en388 pacientes. La hemorragia digestiva de origen oscuro fue la indicaciónmás frecuente (83,30%) seguida de la sospecha de enfermedadde Crohn (7,5%). La angiodisplasia fue la lesión endoscópicamás detectada (42,2%) cuando se analizó la hemorragiadigestiva oscura (OR 3.13 p < 0,001) seguida de la flebectasia(10,6%) y las úlceras sugerentes de enfermedad de Crohn (9,9%).La rentabilidad global en cuanto a la detección de lesiones fue del77,34% con un caso de “no defecación de la cápsula” y por lotanto de necesidad de laparotomía.Conclusiones: la cápsula endoscópica es una técnica consolidaday a medida que se conoce su potencial, se van ampliando susindicaciones. La hemorragia digestiva de origen oscuro es la indicaciónmás frecuente y la angiodisplasia la lesión más identificada.Una vez conocida su eficacia diagnóstica se hace necesario determinarmediante estudios a gran escala y con metodología precisala rentabilidad clínica de la misma

Introduction: the capsule endoscopy (CE), from his approval,has become a first line diagnostic procedure for the study of thesmall bowel disease. The aim of this study is to report our experiencesince the implantation of this technique in our hospital.Material and methods: retrospective review of the CE undertakenin Department of Endoscopy. There was gathered inevery case the age, sex, motive of consultation, previous diagnosticprocedures, capsule endoscopy findings and complication ofthe technique. One took to end a descriptive and analytical analysis.Results: there was achieved a total of 416 explorations in388 patients. The obscure gastrointestinal bleeding was the mostfrequent indication (83.30%) followed by suspected Crohn's disease(7.5%). Angiodisplasia was the endoscopic lesion more frequentlydetected (42.2%), especially, in patients with digestivebleeding of obscure origin (OR 3.13 p < 0.001), followed by theflebectasia (10.6%) and the ulcer suspicious of Crohn´s disease(9.9%). The global diagnostic yield as for the detection of injurieswas 77.34% with a case of “not defecation of the capsule” andtherefore need of laparotomy.Conclusions: the capsule endoscopy is a technique consolidatedand as his potential is known, his indications are extended.The obscure gastrointestinal bleeding is the most frequent indicationand the angiodisplasia the most identified injury. Once knownhis diagnostic yield, larger studies are needed that assess the influenceof capsule endoscopy on clinical outcoumes

Síndrome del nevus gomoso azul (blue rubber bleb nevus) diagnosticado por cápsula endoscópica / Blue rubber bled nevus syndrome diagnosed bu capsule endoscopy

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Feature-based affine-Invariant localization of faces.

We present a novel method for localizing faces in person identification scenarios. Such scenarios involve high resolution images of frontal faces. The proposed algorithm does not require color, copes well in cluttered backgrounds, and accurately localizes faces including eye centers. An extensive analysis and a performance evaluation on the XM2VTS database and on the realistic BioID and BANCA face databases is presented. We show that the algorithm has precision superior to reference methods.

[Differential diagnosis of urinary retention: aneurysm of the iliac artery]. / Aneurysma der A. iliaca als Differenzialdiagnose des Harnverhalts.

A 69-year old male presented with anuric acute renal failure. Abdominal ultrasound at admission revealed a mass in the pelvis thought to be the urinary bladder and the diagnosis of urinary retention was made. When placement of an urinary catheter did not induce urine flow, digital rectal examination was done. Palpation of a pulsating mass finally led to the diagnosis of aneurysm of the iliac artery. Based on this case, the general problem of diagnosing an iliac artery aneurysm is discussed.

Transition to turbulence in particulate pipe flow.

We investigate experimentally the influence of suspended particles on the transition to turbulence. The particles are monodisperse and neutrally buoyant with the liquid. The role of the particles on the transition depends upon both the pipe to particle diameter ratios and the concentration. For large pipe-to-particle diameter ratios the transition is delayed while it is lowered for small ratios. A scaling is proposed to collapse the departure from the critical Reynolds number for pure fluid as a function of concentration into a single master curve.

Renoprotective role of nifedipine during gentamicin therapy: randomized controlled trial.

AIM: To investigate the protective effect of nifedipine, a dihydropyridine calcium-channel blocker, on renal function (glomerular and tubular) in patients treated with gentamicin, an aminoglycoside antibiotic. METHODS: Thirty-two patients with gentamicin sensitive upper urinary tract infection have been screened and randomized to two groups. The placebo group was given gentamicin and placebo, and the intervention group gentamicin and nifedipine. Gentamicin was given in slow intravenous injection every 12 hours for 10 days, and nifedipine 10 mg orally, 3 times a day. RESULTS: Nifedipine administration during gentamicin therapy promoted primarily the glomerular filtration. In 62% of the patients treated with nifedipine creatinine clearance increased significantly by the end of the study. In the placebo group, 69% of the patients had a creatinine clearance significantly below the baseline at the end of the study. The decrease in creatinine clearance by more than 50% from the initial values was found in 2 patients (1 in each group). There was a significant increase in gammaGT/creatinine clearance ratio in both groups at the end of therapy, indicating that nifedipine did not prevent the brush-border membranous enzyme release caused by gentamicin. CONCLUSION: Nifedipine has positive effects on renal hemodynamics in patients treated with gentamicin. Most likely, the mechanism of action is an increase in glomerular filtration caused by preglomerular vasodilatation.

[Dorsal sensory level as a false localizing sign in cervical myelopathy]. / Nivel sensitivo dorsal como falso signo localizador en la mielopatía cervical.

INTRODUCTION: Cervical myelopathy is a common disorder of the spinal cord. The most frequent symptoms are muscle weakness and spasticity starting in the legs. Occasionally the sensory levels are several spinal cord segments below the cervical lesion which makes diagnosis difficult. CLINICAL CASE: We present the case of a 31 year old man who presented (after exercise) with paresthesia and numbness below the left costal margin in the left hemiabdomen and the left leg. On physical examination there was painful superficial tactile thermic hypoaesthesia at the level of D10 on the left side, together with brisk myotatic reflexes of the legs and indifferent bilateral plantar reflexes. Blood and CSF studies were normal. On cervical MR there was a large hernia of the intervertebral disk at C5-C6 and marked involvement of the spinal cord. Progress after surgery was good. Two months after operation he was symptom free and neurological examination was normal. CONCLUSIONS: Diagnosis of cervical myelopathy may be difficult because of the varied symptoms. There may be a dorsal or lumbar sensory level acting as a false localizing sign. The physiopathological mechanism for this is not clear. Different hypotheses have been put forward based on anatomical distribution of the spino-thalamic tract and on indirect factors (vascular, demyelinization, etc.). In a patient with a dorsal sensory level and normal radiological findings at this level, it is important to study levels above this as well to avoid errors of diagnosis and treatment.

[Kaposi's sarcoma in patients with kidney transplantation]. / Kaposiev sarkom u bolesnika s transplantiranim bubregom.

An anti-HIV negative patient with cadaveric renal transplant developed Kaposi's sarcoma of the skin and gingiva 10 months after transplantation, taking triple immunosuppression (cyclosporine, azathioprine and prednisone). After reduction of the cyclosporine dose and complete cessation of azathioprine administration, the tumor regressed without rejection of renal transplant. The patient was a carrier of HLA A2 and DR5. When Kaposi's sarcoma was diagnosed serologic tests revealed reactivation of cytomegalovirus (CMV) infection. All this combined with considerable pharmacological immunosuppression, made the patient prone to develop Kaposi's sarcoma, which can regress with adequate reduction of immunosuppression.

Serum fructosamine is not a useful screening test for gestational diabetes.

Serum fructosamine was measured in 569 samples of pregnant women without gestational diabetes. We defined abnormal fructosamine as mean + 2SD, and analysed its potential value to detect patients with gestational diabetes diagnosed with current screening criteria. We found serum fructosamine to be an insensitive parameter: Measured at the time of a positive 50 g glucose screening, SF would have detected 4/48 gestational diabetes.