Comparative physicochemical analysis of chitin quality of the two tagmata in the exoskeleton of the horseshoe crab Limulus polyphemus.

Recently, chitin biopolymer has received much attention as a wide variety of biomedical application for this and its derivatives have been reported, in fact, the study of non-conventional species as alternative sources of them compounds has taken particular interest. Here, we present a comparative physicochemical survey of the two tagmata in the exoskeleton of the horseshoe crab Limulus polyphemus: the prosoma and the opisthosoma, collected in Yucatán, Mexico. The characterization included CHNSO analysis, FTIR, TGA, DSC, XRD, and SEM. The CHNSO analysis revealed that C is present in the highest proportion (∼45 %) and that chemical composition did not show significant differences (P < 0.05) between the two tagmata. FTIR spectra of two tagmata presented a wide characteristic band of the chitin between 3600 and 3000 cm-1, confirming the presence of this biopolymer in the exoskeleton studied. TGA and DTGA profiles resulted very similar for both tagmata being the residual mass at 650 °C of around 30 % for both samples; these values were associated to the presence of minerals. SEM micrographs showed a porous matrix with infinite large number of irregularly shaped particles. Results show that both tagmata are made up of chitin, and they seem to have a high mineral content.

Restoration of Anatomic Parameters and Syndesmotic Reduction After Intramedullary Nailing of Distal Fibular Fractures.

Background: Intramedullary nailing of the fibula (FN) is a method of fixation that has proven to be useful for treating distal fibular fractures (DFs). FN minimizes soft tissue complications and provides similar stability to plating, with fewer hardware-related symptoms. Nevertheless, FN has been associated with syndesmotic malreduction and the incapacity of restoring length and rotation of the fibula. We aimed to evaluate the fibular position and syndesmotic reduction after fixation with FN compared with the uninjured ankle in the immediate postoperative period. Methods: Prospective cohort study. Patients with DF fractures treated with IN between January 2017 and January 2020 were included. Immediate postoperative bilateral ankle CT was obtained in all cases. Fibular rotation, length, and translation as well as syndesmotic diastasis were measured on both ankles and compared by 3 independent observers. Results: Twenty-eight patients were included (16 women). The mean age was 46 years (range 16-91). Fracture type distribution according to AO/ASIF classification included 19 patients with 44.B (67.9%), 8 patients with 44.C (28.6%), and 1 patient with a 44.A fracture (3.6%). No significant differences were identified considering fibular rotation (P = .661), syndesmotic diastasis (P = .147), and fibular length (P = .115) between the injured and uninjured ankle. Fibular translation had statistical differences (P = .01) compared with the uninjured ankle. The intraclass correlation coefficient showed an excellent concordance between observers except for fibular translation on the injured ankle. Conclusion: In this cohort, fixation of DF fractures with FN allows restoration of anatomical parameters of the ankle in terms of fibular rotation, length, and syndesmotic diastasis. However, fibular translation had significant differences compared with the uninjured ankle based on bilateral CT scan evaluation. Level of Evidence: Level II, prospective cohort study.

Sensors and Biosensors in Organs-on-a-Chip Platforms.

Biosensors represent a powerful analytical tool for analyzing biomolecular interactions with the potential to achieve real-time quantitative analysis with high accuracy using low sample volumes, minimum sample pretreatment with high potential for the development of in situ and highly integrated monitoring platforms. Considering these advantages, their use in cell-culture systems has increased over the last few years. Between the different technologies for cell culture, organs-on-a-chip (OOCs) represent a novel technology that tries to mimic an organ's functionality by combining tissue engineering/organoid with microfluidics. Although there are still challenges to achieving OOC models with high organ mimicking relevance, these devices can offer effective models for drug treatment development by identifying drug targets, screening toxicity, and determining the potential effects of drugs in living beings. Consequently, in the future, we might replace animal studies by offering more ethical test models. Considering the relevance that different physiological and biochemical parameters have in the correct functionality of cells, sensing and biosensing platforms can offer an effective way for the real-time monitoring of physiological parameters and, in our opinion, more relevant, the secretion of biomarkers such as cytokines, growth factors, and others related with the influence of drugs or other types of stimulus in cell metabolism. Keeping this concept in mind, in this chapter, we focus on describing the potential use of sensors and biosensors in OOC devices to achieve fully integrated platforms that monitor physiological parameters and cell metabolism.

Disposable Polymeric Nanostructured Plasmonic Biosensors for Cell Culture Adhesion Monitoring.

Over the last years, optical biosensors based on plasmonic nanomaterials have gained great scientific interest due to their unquestionable advantages compared to other biosensing technologies. They can achieve sensitive, direct, and label-free analysis with exceptional potential for multiplexing and miniaturization. Recently, it has been demonstrated the potential of using optical discs as high throughput nanotemplates for the development of plasmonic biosensors in a cost-effective way. This work is a pilot study focused on the development of an integrated plasmonic biosensor for the monitoring of cell adhesion and growth of human retinal pigmented cell line (ARPE-19) under different media conditions (0 and 2% of FBS). We observed an increase of the plasmonic band displacement under 2% FBS compared to 0% conditions over time (1, 3, and 5 h). These preliminary results show that the proposed plasmonic biosensing approach is a direct, non-destructive, and real-time tool that could be employed in the study of living cells behavior and culture conditions. Furthermore, this setup could assess the viability of the cells and their growth over time with low variability between the technical replicates improving the experimental replicability.

Direct and Label-Free Monitoring of Albumin in 2D Fatty Liver Disease Model Using Plasmonic Nanogratings.

Non-alcoholic fatty liver (NAFLD) is a metabolic disorder related to a chronic lipid accumulation within the hepatocytes. This disease is the most common liver disorder worldwide, and it is estimated that it is present in up to 25% of the world's population. However, the real prevalence of this disease and the associated disorders is unknown mainly because reliable and applicable diagnostic tools are lacking. It is known that the level of albumin, a pleiotropic protein synthesized by hepatocytes, is correlated with the correct function of the liver. The development of a complementary tool that allows direct, sensitive, and label-free monitoring of albumin secretion in hepatocyte cell culture can provide insight into NAFLD's mechanism and drug action. With this aim, we have developed a simple integrated plasmonic biosensor based on gold nanogratings from periodic nanostructures present in commercial Blu-ray optical discs. This sensor allows the direct and label-free monitoring of albumin in a 2D fatty liver disease model under flow conditions using a highly-specific polyclonal antibody. This technology avoids both the amplification and blocking steps showing a limit of detection within pM range (≈0.26 ng/mL). Thanks to this technology, we identified the optimal fetal bovine serum (FBS) concentration to maximize the cells' lipid accumulation. Moreover, we discovered that the hepatocytes increased the amount of albumin secreted on the third day from the lipids challenge. These data demonstrate the ability of hepatocytes to respond to the lipid stimulation releasing more albumin. Further investigation is needed to unveil the biological significance of that cell behavior.

Cervical metastasis of squamous cell carcinoma of the head and neck. Therapeutic options.

INTRODUCTION: Patients with bulky metastases of squamous cell carcinoma of the head and neck represent a challenge for the therapeutic decision; balance between oncological control and complications should be achieved. The therapeutic sequence has no impact on survival but sequelae. OBJECTIVE: We analyze the oncological results in patients with bulky metastases on the neck treated with induction chemotherapy and with up-front neck dissection. METHOD: Retrospective analysis of patients undergoing treatment for cervical lymph node metastasis of squamous cell carcinoma; The therapeutic sequence was decided based on volume, resectability, site, and size of the primary and general condition of the patient. Overall survival was calculated based on human papilloma virus (HPV) status. RESULTS: There were 30 patients, 22 men and eight women with a mean age of 57 years, 10 N3 and 20 N2. In 13 the HPV was positive, in 5 negative and in 12 the determination was not made. Seven patients were treated with initial chemotherapy, and 23 underwent neck dissection; the 5-year survival was 25%, and the prognosis was better in the positive HPV. CONCLUSION: The treatment of cervical metastasis depends on the possibility of resection. We should favor the initial surgery. The HPV is a factor of good prognosis.

INTRODUCCIÓN: Los pacientes con metástasis voluminosas de carcinoma epidermoide de cabeza y cuello representan un reto para la decisión terapéutica; se debe lograr un equilibrio entre el control oncológico y las complicaciones. La secuencia terapéutica no tiene impacto en la supervivencia, pero sí en las secuelas. OBJETIVO: Conocer los resultados oncológicos de pacientes con metástasis en el cuello tratados con cirugía inicial y con quimioterapia de inducción. MÉTODO: Análisis retrospectivo de pacientes sometidos a tratamiento por metástasis ganglionares cervicales de carcinoma epidermoide. La secuencia terapéutica se decidió basándose en el volumen, la resecabilidad, el sitio y el tamaño del tumor primario, y el estado general del paciente. Se calculó la supervivencia global y según el estado de portador o no del virus del papiloma humano (VPH). RESULTADOS: Se incluyeron 30 pacientes, 22 hombres y 8 mujeres, con una media de edad de 57 años. En cuanto al estadio, 10 eran N3 y 20 eran N2. En 13 el VPH fue positivo, en 5 fue negativo y en 12 no se efectuó la determinación. Siete pacientes fueron tratados con quimioterapia inicial y 23 fueron sometidos a disección de cuello. La supervivencia a 5 años fue del 25% y el pronóstico fue mejor en los VPH positivos. CONCLUSIÓN: El tratamiento de las metástasis cervicales depende de su resecabilidad. Hay que favorecer la cirugía inicial. El VPH es un factor de buen pronóstico.

Gold/silver/gold trilayer films on nanostructured polycarbonate substrates for direct and label-free nanoplasmonic biosensing.

Ultrasmooth gold/silver/gold trilayer nanostructured plasmonic sensors were obtained using commercial Blu-ray optical discs as nanoslits-based flexible polymer substrates. A thin gold film was used as an adhesion and nucleation layer to improve the chemical stability and reduce the surface roughness of the overlying silver film, without increasing ohmic plasmon losses. The structures were physically and optically characterized and compared with nanostructures of single gold layer. Ultrasmooth and chemically stable trilayer nanostructures with a surface roughness <0.5 nm were obtained following a simple and reproducible fabrication process. They showed a figure of merit (FOM) value up to 69.2 RIU-1 which is significantly higher (more than 95%) than the gold monolayer counterpart. Their potential for biosensing was demonstrated by employing the trilayer sensor for the direct and refractometric (label-free) detection of C-reactive protein (CRP) biomarker in undiluted urine achieving a Limit of Detection (LOD) in the pM order.

Fungal Screening on Olive Oil for Extracellular Triacylglycerol Lipases: Selection of a Trichoderma harzianum Strain and Genome Wide Search for the Genes.

A lipolytic screening with fungal strains isolated from lignocellulosic waste collected in banana plantation dumps was carried out. A Trichoderma harzianum strain (B13-1) showed good extracellular lipolytic activity (205 UmL-1). Subsequently, functional screening of the lipolytic activity on Rhodamine B enriched with olive oil as the only carbon source was performed. The successful growth of the strain allows us to suggest that a true lipase is responsible for the lipolytic activity in the B13-1 strain. In order to identify the gene(s) encoding the protein responsible for the lipolytic activity, in silico identification and characterization of triacylglycerol lipases from T. harzianum is reported for the first time. A survey in the genome of this fungus retrieved 50 lipases; however, bioinformatic analyses and putative functional descriptions in different databases allowed us to choose seven lipases as candidates. Suitability of the bioinformatic screening to select the candidates was confirmed by reverse transcription polymerase chain reaction (RT-PCR). The gene codifying 526309 was expressed when the fungus grew in a medium with olive oil as carbon source. This protein shares homology with commercial lipases, making it a candidate for further applications. The success in identifying a lipase gene inducible with olive oil and the suitability of the functional screening and bioinformatic survey carried out herein, support the premise that the strategy can be used in other microorganisms with sequenced genomes to search for true lipases, or other enzymes belonging to large protein families.

A label-free nanostructured plasmonic biosensor based on Blu-ray discs with integrated microfluidics for sensitive biodetection.

Nanostructure-based plasmonic biosensors have quickly positioned themselves as interesting candidates for the design of portable optical biosensor platforms considering the potential benefits they can offer in integration, miniaturization, multiplexing, and real-time label-free detection. We have developed a simple integrated nanoplasmonic sensor taking advantage of the periodic nanostructured array of commercial Blu-ray discs. Sensors with two gold film thicknesses (50 and 100nm) were fabricated and optically characterized by varying the oblique-angle of the incident light in optical reflectance measurements. Contrary to the use normal light incidence previously reported with other optical discs, we observed an enhancement in sensitivity and a narrowing of the resonant linewidths as the light incidence angle was increased, which could be related to the generation of Fano resonant modes. The new sensors achieve a figure of merit (FOM) up to 35 RIU-1 and a competitive bulk limit of detection (LOD) of 6.3×10-6 RIU. These values significantly improve previously reported results obtained with normal light incidence reflectance measurements using similar structures. The sensor has been combined with versatile, simple, ease to-fabricate microfluidics. The integrated chip is only 1cm2 (including a PDMS flow cell with a 50µm height microfluidic channel fabricated with double-sided adhesive tape) and all the optical components are mounted on a 10cm×10cm portable prototype, illustrating its facile miniaturization, integration and potential portability. Finally, to assess the label-free biosensing capability of the new sensor, we have evaluated the presence of specific antibodies against the GTF2b protein, a tumor-associate antigen (TAA) related to colorectal cancer. We have achieved a LOD in the pM order and have assessed the feasibility of directly measuring biological samples such as human serum.

[Mandibular osteoradionecrosis (ORN) as a side effect of head and neck cancer treatment: Factors that induce it]. / Osteoradionecrosis (ORN) mandibular como efecto colateral del tratamiento del cáncer de cabeza y cuello: factores que la inducen.

INTRODUCTION: Osteoradionecrosis of the mandible is a relatively common complication in patients with head and neck cancer undergoing radiotherapy or concomitant chemoradiotherapy, characterized by exposure of the mandibular bone either in the mouth or in the facial skin, with no improvement with conservative treatment for six months. The risk factors are radiotherapy in head and neck region, lack of dental prophylaxis before treatment and dental extraction. MATERIAL AND METHODS: Retrospective observational study analyzing incidence and etiologic factors of osteoradionecrosis in 250 patients undergoing radiotherapy or combined treatment of cervicofacial area between 2002 and 2010. RESULTS: 25 patients were included; the horizontal branch was the most affected area, followed by the anterior arch. Associated factors were: stage (T4a and T4b), tumor location (oral cavity), dental extraction pre or post-radiotherapy, and radiotherapy time (pre-or postoperative); 72% had association with tooth extraction. Only five patients had control with conservative measures, and 20 required some type of mandibulectomy, only three of them were candidates for reconstruction with fibular free flap; none received treatment in a hyperbaric chamber. CONCLUSIONS: The data suggest that osteoradionecrosis has a multifactorial origin, and prevention is the best alternative and includes pretreatment dental prophylaxis to avoid tooth extractions and close monitoring and surveillance in order to identify early osteoradionecrosis. Most patients require mandible resection as definitive treatment.

[Laryngeal conservative surgery in patients candidates for combined treatment with chemo-radiotherapy]. / Cirugía conservadora de laringe en pacientes candidatos a tratamiento combinado con quimio-radiación por cáncer laríngeo.

BACKGROUND: The standard of care for advanced-stage laryngeal cancer is combined treatment (chemo-radiotherapy). However, the complications with this treatment are not few, mainly in swallowing. Conservative laryngeal surgery remains an effective alternative for cancer control without the complications of chemo-radiotherapy. MATERIAL AND METHODS: Retrospective study was conducted on patients with laryngeal cancer cT3, cN0 with paraglottic infiltration, fixation of the vocal cord, minimal invasion of the hyo-thyroepiglottic space, but with normal arytenoid mobility and no sub-glottic extension, were treated with subtotal supracricoid laryngectomy. Complications, sequels of treatment, and local recurrence were evaluated. Bronchial aspiration was studied with radioactive swallow. RESULTS: There were 25 patients, 22 with negative surgical margins, one had tumour contact with the surgical margins, and 2 were positive. Two patients received postoperative radiotherapy. The mean decannulation was 15 days and removal of nasogastric tube 25 days. During the mean follow-up of 26 months, none of the patients had tumour recurrence or required conversion to total laryngectomy. In all patients swallowing has been normal and none required permanent or temporary tracheotomy or definitive gastrostomy. The voice is considered intelligible in all patients. Radioactive swallow showed aspiration in 15/25 patients, with none being clinically relevant. There were postoperative complications in 5 patients, and 4 patients required re-intervention but no conversion to total laryngectomy. CONCLUSION: Conservative surgery is an effective surgical-alternative to chemo-radiotherapy in patients with locally advanced laryngeal cancer, providing oncological control, acceptable complications and minimal sequels. Although most patients have aspiration, this does not affect functional status.

[Clinical characteristics of malignant tumours originating in the external ear]. / Características clínicas de los tumores malignos originados en el pabellón auricular.

BACKGROUND: Skin tumours that originate in the external ear are common in individuals with type 1 skin and phenotype 1 and 2. The skin cancer is associated with chronic or intermittent, but intense sunlight. The most common malignant tumour is basal cell carcinoma, followed by squamous cell carcinoma and melanoma. The diagnosis of squamous cell skin cancer in head and neck area is usually made in the advanced stages and has a poor prognosis. MATERIAL AND METHODS: A cross-sectional, retrospective analysis was performed on the database of patients with skin cancer of the external ear treated between 2011 and 2014. Histology type, stage, rate of clinical and occult metastases, and rate of loco-regional recurrence were evaluated. RESULTS: Of the 42 patients included there were, 25 squamous cell carcinomas, 11 basal cell carcinomas, and 6 invasive melanomas. The rate of lymph node metastases in patients with squamous cell carcinoma was 32%, mostly in the parotid and peri-parotid region, 7% of them with capsular rupture, 2/17 were staged as cN0, and 11.7% had occult metastases. All patients with nodal metastasis were classified as T2 with ulceration. None of the patients with basal cell carcinoma had lymph node metastases. All melanomas were superficial extension type with mean level of Breslow of 3 mm. All underwent lymphatic mapping and sentinel node biopsy, with only one having metastases in the sentinel node. CONCLUSION: The most frequent tumour in the external ear in this series was squamous cell carcinoma. The possibility of lymph node metastases is associated with tumour size (T). Node dissection should be systematic in patients with T2 or greater.

Estudio multicéntrico hospitalario en España, México y Cuba de actitud hacia la donación de vivo hepática / Hospital-based multicenter study in Spain, Mexico and Cuba on attitudes to living liver donation

INTRODUCCIÓN: Dado el déficit de hígados para trasplante se está potenciando la donación de vivo hepática (DVH) en el ámbito de habla hispana. Para ello es fundamental que los profesionales de centros hospitalarios estén a favor de dicha donación, dado que son una pieza clave en este tratamiento y son un grupo generador de opinión ante la población. Objetivo Analizar la actitud hacia la donación de vivo hepática (DVH) entre el personal hospitalario de centros sanitarios de España y Latinoamérica MATERIAL Y MÉTODO: Del «Proyecto Colaborativo Internacional Donante» se seleccionaron 10 centros hospitalarios, 3 de España, 5 de México y 2 de Cuba. Muestra aleatoria y estratificada por tipo de servicio y categoría laboral. Se valora la actitud hacia la DVH a través de un cuestionario validado de aspectos psicosociales. El cuestionario fue anónimo y autoadministrado. Estadística: test de la t de Student, de la χ2 y análisis de regresión logística. RESULTADOS: De los 2.618 profesionales encuestados, el 85% (n = 2.231) está a favor de la DVH relacionada, y de ellos el 31% (n = 804) a favor de la DVH no relacionada. No se asocian con dicha actitud ni el país del encuestado, ni las variables sociopersonales ni las laborales. Los factores que se asocian a la actitud favorable hacia la DVH relacionada son haber tenido experiencia personal con la donación y el trasplante (p < 0,001), estar a favor de la donación de cadáver (p < 0,001), creer en la posibilidad de necesitar un trasplante para sí mismo (p < 0,001), estar a favor de la donación de vivo renal (p < 0,001), aceptar un hígado procedente de donante vivo si fuera necesario (p < 0,001), haber comentado con la familia sobre la donación y el trasplante (p < 0,001), la actitud favorable de la pareja hacia la donación y el trasplante (p < 0,001), realizar actividades de tipo prosocial (p < 0,001), ser católico (p = 0,040), creer el encuestado que su religión está a favor de la donación y el trasplante (p < 0,001), y no preocuparle la posible mutilación del cuerpo tras la donación (p < 0,001). CONCLUSIONES: La actitud hacia la DVH referida entre el personal hospitalario de España y Latinoamérica es favorable, y está asociada con factores relacionados directa e indirectamente con la donación y el trasplante, factores familiares, religiosos y de actitud hacia el cuerpo

INTRODUCTION: Given the lack of a sufficient number of livers available for transplantation, living liver donation (LLD) is being developed in the Spanish-speaking world. To do this, it is essential that health workers in hospitals are in favor of such donation, given that they are a key component in this treatment and that their attitudes influence public opinion. OBJECTIVE: To analyze attitude toward LLD among hospital personnel from healthcare centers in Spain and Latin America. MATERIAL AND METHOD: Ten hospitals were selected from the «International Donor Collaborative Project»: 3 from Spain, 5 from Mexico and 2 from Cuba. Random sampling stratified by type of service and job category was used. Attitudes to LLD were evaluated through a validated questionnaire on psychosocial aspects. The questionnaire was anonymous and self-administered. Statistical tests consisted of Student's T test, the chi-square test and logistic regression analysis. RESULTS: Of the 2,618 employees surveyed, 85% (n = 2,231) were in favor of related LLD; of these, 31% (n = 804) were in favor of unrelated LLD. No association was found between the country of the interviewed, personal-social variables or work-related variables. The following factors were associated with a favorable attitude toward related LLD donation: having had personal experience of donation and transplantation (P < .001); being in favor of deceased donation (P < .001); believing that one might need a possible transplant (P < .001); being in favor of living kidney donation (P < .001); being willing to accept a liver from a living donor (P < .001); having discussed the matter of donation and transplantation within the family (P < .001) and with one's partner (P < .001); carrying out pro-social type activities (P < .001); being Catholic (P = .040); believing that one's religion is in favor of donation and transplantation (P < .001); and not being concerned about the possible mutilation of the body after donation (P < .001). CONCLUSIONS: Hospital personnel from Spain and Latin America had a favorable attitude toward LLD, which was associated with factors directly and indirectly related to donation and transplantation, family and religious factors, and attitudes toward the body

[Dermoscopy in cutaneous melanoma]. / Dermatoscopia en melanoma cutáneo.

BACKGROUND: The mortality of cutaneous melanoma has not declined over the past 50 years. The only interventions that can reduce mortality are primary prevention and early diagnosis, and the dermoscopic evaluation is essential to achieve this. Dermoscopy identifies characteristics of melanoma that would go unnoticed to the naked eye. The aim of this paper is to report the most frequent dermoscopic findings in patients diagnosed with in situ and invasive melanoma. MATERIAL AND METHODS: An observational and retrospective study of contact dermoscopy was performed using LED DermliteTM and camera DermliteTM dermoscope. The findings evaluated were: asymmetry in two axes, association of colours, lack of pigment, irregular points, atypical network, pseudopods, blue veil, ulceration, and peri-lesional pink ring. These dermoscopic findings were compared with the histological diagnosis. RESULTS: The study included 65 patients with cutaneous melanoma; 10 in situ, and 55 invasive. The mean Breslow in invasive melanoma was 3 mm. Most patients (35) had localization in extremities. In all patients, the most frequent dermoscopic finding was asymmetry in two axes, followed by association of two or more colours; in melanoma in situ, asymmetry was the most frequent, followed by atypical-irregular points. In invasive melanoma asymmetry in two axes, the association of two or more colours, and pseudopods, were the most frequent findings. CONCLUSION: Asymmetry in two axes is the most common dermoscopic finding in in situ and invasive melanoma. The presence of two or more colours in a pigmented lesion should be suspected in an invasive melanoma.

Subtalar arthroscopy: indications, technique and results.

The emergence of subtalar arthroscopy has improved the understanding and accuracy of diagnosing several hindfoot pathologic conditions, in particular, sinus tarsi syndrome. Subtalar arthroscopy has evolved into a useful diagnostic and therapeutic tool. The surgeon's experience is still essential to achieve good results. This article reviews the clinical indications, surgical techniques, and outcomes of subtalar arthroscopy.

Design and test of a low-cost RGB sensor for online measurement of microalgae concentration within a photo-bioreactor.

In this study, a low-cost RGB sensor is developed to measure online the microalgae concentration within a photo-bioreactor. Two commercially available devices, i.e., a spectrophotometer for offline measurements and an immersed probe for online measurements, are used for calibration and comparison purposes. Furthermore, the potential of such a sensor for estimating other variables is illustrated with the design of an extended Luenberger observer.

Evaluación integral de competencias en la formación de médicos en México. Estudio interinstitucional / Comprehensive evaluation of the competences in the training of physicians in Mexico. An interinstitutional study

Introducción: La educación médica en México no tiene referentes nacionales de evaluación integral que permitan identificar fortalezas y debilidades educativas. Objetivos: Valorar la factibilidad de colaboración interinstitucional para la evaluación en medicina y analizar integralmente conocimientos, destrezas y actitudes médicas. Sujetos y métodos: Ocho facultades de medicina definieron las competencias necesarias al concluir el año previo al internado. Se aplicó a distancia un examen con 105 reactivos de opción múltiple, además de un examen clínico objetivo estructurado (ECOE) con 18 estaciones. Áreas evaluadas: cirugía, ginecología, medicina interna, medicina comunitaria y pediatría. Universo: estudiantes próximos al inicio del internado. Muestra de acuerdo a la matrícula de cada institución. Los resultados se analizaron en global, área del conocimiento e institución. Resultados: Participaron 199 estudiantes de ocho facultades en las dos evaluaciones, 99 hombres y 100 mujeres, con una edad media de 21 años. El rendimiento global por área fue: cirugía, 60,22 %; ginecología, 61,90%; medicina interna, 57,97%; pediatría, 52,25%, y salud pública, 49,68%. La media total fue del 56.40%. Por institución, la mediana se mantuvo entre 35,91 y 51,06%. Conclusiones: Es factible la participación interinstitucional en evaluaciones integrales de medicina. La plataforma utilizada permitió la aplicación de exámenes a distancia simultáneos. El ECOE es factible y útil para evaluar habilidades y destrezas, y es recomendable que todas las escuelas lo utilicen. Se identifican fortalezas en ginecología y cirugía, así como debilidades en pediatría y, sobre todo, en salud pública y medicina comunitaria, que pueden considerarse referentes útiles para ajustes en los programas educativos. Se requiere incrementar el tamaño de la muestra

Introduction: The medical education in México does not have any national tests which could comprehensively evaluate and hence identify the educational strengths and weaknesses. Aims: To estimate the feasibility of inter institutional collaboration to evaluate the medical knowledge, and to evaluate comprehensively the medical knowledge, skills and attitudes. Subjects and methods: Eight faculties of medicine defined the competences needed at the end of the year before starting the internship. An online exam was given, it was composed of 105 multiple choice questions plus a objective structured clinical exam (OSCE) covering 18 areas. Subjects evaluated: Surgery, Gynecology, Internal Medicine, Community Medicine and Pediatrics. Sample: students who were about to start the internship. This sample was made according to the registration of each institution. The results were analyzed as a whole; the knowledge in each area and the institution. Results: 199 students, from eight faculties, participated in both evaluations, 99 men and 100 women aged 21. The global performance by area was: Surgery 60.22%, Gynecology 61.60%, Internal Medicine 57.97%, Pediatrics 52.25%, Public Health 49.68%. The total average was 56.40%. Results by institution: mean result between 35.91 and 51.06%. Conclusions: The participation to evaluate comprehensively the medical knowledge is feasible inter institutionally. The platform used made possible to administer simultaneously on line exams. The OSCE is feasible and useful to evaluate competences and skills. It is recommendable that all the schools use it. Strengths were identified in gynecology, and surgery as well as weaknesses in pediatrics and mainly in public health and community medicine. These results could be considered as useful references to adjust the syllabus. It is required to increase the size of the sample

[Hospital-based multicenter study in Spain, Mexico and Cuba on attitudes to living liver donation]. / Estudio multicéntrico hospitalario en España, México y Cuba de actitud hacia la donación de vivo hepática.

INTRODUCTION: Given the lack of a sufficient number of livers available for transplantation, living liver donation (LLD) is being developed in the Spanish-speaking world. To do this, it is essential that health workers in hospitals are in favor of such donation, given that they are a key component in this treatment and that their attitudes influence public opinion. OBJECTIVE: To analyze attitude toward LLD among hospital personnel from healthcare centers in Spain and Latin America. MATERIAL AND METHOD: Ten hospitals were selected from the «International Donor Collaborative Project¼: 3 from Spain, 5 from Mexico and 2 from Cuba. Random sampling stratified by type of service and job category was used. Attitudes to LLD were evaluated through a validated questionnaire on psychosocial aspects. The questionnaire was anonymous and self-administered. Statistical tests consisted of Student's T test, the chi-square test and logistic regression analysis. RESULTS: Of the 2,618 employees surveyed, 85% (n=2,231) were in favor of related LLD; of these, 31% (n=804) were in favor of unrelated LLD. No association was found between the country of the interviewed, personal-social variables or work-related variables. The following factors were associated with a favorable attitude toward related LLD donation: having had personal experience of donation and transplantation (P<.001); being in favor of deceased donation (P<.001); believing that one might need a possible transplant (P<.001); being in favor of living kidney donation (P<.001); being willing to accept a liver from a living donor (P<.001); having discussed the matter of donation and transplantation within the family (P<.001) and with one's partner (P<.001); carrying out pro-social type activities (P<.001); being Catholic (P=.040); believing that one's religion is in favor of donation and transplantation (P<.001); and not being concerned about the possible mutilation of the body after donation (P<.001). CONCLUSIONS: Hospital personnel from Spain and Latin America had a favorable attitude toward LLD, which was associated with factors directly and indirectly related to donation and transplantation, family and religious factors, and attitudes toward the body.

Quantification of total pigments in citrus essential oils by thermal wave resonant cavity photopyroelectric spectroscopy.

A general theory of thermal wave resonant cavity photopyroelectric spectroscopy (TWRC-PPE) was recently proposed by Balderas-López (2012) for the thermo-optical characterisation of substances in a condensed phase. This theory is used to quantify the total carotenoids and chlorophylls in several folded and un-folded citrus essential oils to demonstrate the viability of using this technique as an alternative analytical method for the quantification of total pigments in citrus oils. An analysis of variance (ANOVA) reveals significant differences (p < 0.05) among the means of optical absorption coefficient data for the folding degree and fruit type in citrus oils. The experimental results show that TWRC-PPE spectroscopy can be used to quantify concentrations up to five times higher of total carotenoids and chlorophylls in citrus oils than UV-Vis spectroscopy without sample preparation or dilution. The optical limits of this technique and possible interference are also described.

Synthesis and structure of sulfur derivatives from 2-aminobenzimidazole.

The reactions of the benzimidazole nitrogen atoms and the exocyclic amino group of 2-aminobenzimidazole with CS2 in NaOH basic medium followed by methylation with methyl iodide was explored. With careful control of the stoichiometric quantities and addition sequences, this set of reactions allows the selective functionalization of the benzimidazole ring with N-dithiocarbamate, S-methyldithiocarbamate or dimethyl- dithiocarboimidate groups. The products were characterized by 1H-, 13C-NMR spectroscopy and three of them by X-ray diffraction analysis. The preferred isomers, tautomers and conformers were established.