ARHGAP17 regulates the spatiotemporal activity of Cdc42 at invadopodia.

Invadopodia formation is regulated by Rho GTPases. However, the molecular mechanisms that control Rho GTPase signaling at invadopodia remain poorly understood. Here, we have identified ARHGAP17, a Cdc42-specific RhoGAP, as a key regulator of invadopodia in breast cancer cells and characterized a novel ARHGAP17-mediated signaling pathway that controls the spatiotemporal activity of Cdc42 during invadopodia turnover. Our results show that during invadopodia assembly, ARHGAP17 localizes to the invadopodia ring and restricts the activity of Cdc42 to the invadopodia core, where it promotes invadopodia growth. Invadopodia disassembly starts when ARHGAP17 translocates from the invadopodia ring to the core, in a process that is mediated by its interaction with the Cdc42 effector CIP4. Once at the core, ARHGAP17 inactivates Cdc42 to promote invadopodia disassembly. Our results in invadopodia provide new insights into the coordinated transition between the activation and inactivation of Rho GTPases.

Formación de habilidades clínicas para el diagnóstico de la lepra por estudiantes de Medicina / Training of clinical skills for the diagnosis of leprosy in medical students

RESUMEN Introducción: el proceso formación de habilidades clínicas para diagnosticar la lepra por estudiantes de quinto año de Medicina constituye un eslabón importante en el diagnóstico precoz de la enfermedad y su control. Objetivo: sistematizar los referentes teóricos que sustentan el proceso de formación de los estudiantes de quinto año de Medicina en el diagnóstico de la lepra. Métodos: para la recogida de la información se revisaron artículos de las páginas Scielo, Google Scholar, MEDISAN, Elsevier y tesis doctorales en ciencias de la educación médica, digitalizados e impresos para un total de 57; de ellos fueron seleccionados 26 sobre la temática estudiada. Desarrollo: se realizó una sistematización sobre los conceptos de formación, habilidad y desarrollo vinculados al examen dermatoneurológico y el proceso de formación de los estudiantes de quinto año de Medicina, así como la contribución de esta habilidad en el diagnóstico precoz de la lepra. Conclusiones: el análisis realizado sobre la formación de los estudiantes de quinto año de Medicina en el diagnóstico de la lepra permitió establecer un acercamiento a sus referentes teóricos, así como reconocer la necesidad de desarrollar nuevos métodos de enseñanza que les brinden el conocimiento y la práctica necesaria para enfrentar los retos de la demandante situación higiénico-epidemiológica con acciones dirigidas al paciente, la familia y la comunidad.

ABSTRACT Introduction: the process of training clinical skills to diagnose leprosy by fifth-year medical students constitutes an important element in the early diagnosis of the disease and its control. Objective: to systematize the theoretical references to support the training process of fifth year Medicine students in the diagnosis of leprosy. Methods: for data collection, articles from the pages Scielo, Google Scholar, MEDISAN, Elsevier and doctoral theses in medical education sciences, either electronic or printed were reviewed for a total of 57; out of them, 26 were selected on the subject studied. Development: Systematization was carried out on the concepts of training, skill and development linked to the dermatoneurological examination and the training process of fifth year Medicine students, as well as the contribution of this skill in the early diagnosis of leprosy. Conclusions: the systematization carried out on the training of fifth-year medical students in the diagnosis of leprosy allowed establishing an approach to their theoretical references, as well as recognizing the need to develop new teaching methods to provide them with the necessary knowledge and practice to face the challenges of the demanding hygienic-epidemiological situation with actions aimed at the patient, the family and the community.

Antimicrobial Activity and Prevention of Bacterial Biofilm Formation of Silver and Zinc Oxide Nanoparticle-Containing Polyester Surfaces at Various Concentrations for Use.

Food contact surfaces are primary sources of bacterial contamination in food industry processes. With the objective of preventing bacterial adhesion and biofilm formation on surfaces, this study evaluated the antimicrobial activity of silver (Ag-NPs) and zinc oxide (ZnO-NPs) nanoparticle-containing polyester surfaces (concentration range from 400 ppm to 850 ppm) using two kinds of bacteria, Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli), and the prevention of bacterial biofilm formation using the pathogen Listeria monocytogenes. The results of antimicrobial efficacy (reductions ≥ 2 log CFU/cm2) showed that at a concentration of 850 ppm, ZnO-NPs were effective against only E. coli (2.07 log CFU/cm2). However, a concentration of 400 ppm of Ag-NPs was effective against E. coli (4.90 log CFU/cm2) and S. aureus (3.84 log CFU/cm2). Furthermore, a combined concentration of 850 ppm Ag-NPs and 400 ppm ZnO-NPs showed high antimicrobial efficacy against E. coli (5.80 log CFU/cm2) and S. aureus (4.11 log CFU/cm2). The results also showed a high correlation between concentration levels and the bacterial activity of Ag-ZnO-NPs (R2 = 0.97 for S. aureus, and R2 = 0.99 for E. coli). They also showed that unlike individual action, the joint action of Ag-NPs and ZnO-NPs has high antimicrobial efficacy for both types of microorganisms. Moreover, Ag-NPs prevent the biofilm formation of L. monocytogenes in humid conditions of growth at concentrations of 500 ppm. Additional studies under different conditions are needed to test the durability of nanoparticle containing polyester surfaces with antimicrobial properties to optimize their use.

Microscopic analysis and microstructural characterization of the organic and inorganic components of dairy fouling during the cleaning process.

This study evaluated the organic residues of milk fouling using fluorescence and confocal laser scanning microscopy. The inorganic content was analyzed with energy-dispersive X-ray spectroscopy, complemented with inductively coupled plasma optical emission spectrometry. These techniques were applied to evaluate milk fouling cleanliness using an alkaline product and an enzymatic formulation based on protease and amylase. The results showed that the efficiency of enzymatic cleaning was 87.1% when it was evaluated at 55°C for 30 min, and with a medium of pH 8.5. No difference was found from the efficacy in eliminating dairy fouling observed for the chemical cleaning (86.9%). The fluorescence microscopy proved useful for determining the organic solid components in the outer layer of the dairy fouling. The fouling spatial disposition in 3 dimensions, obtained by confocal laser scanning microscopy, showed that it was formed of 51.3% sugars, 9.3% fats, and 39.4% proteins, with the enzymatic cleaning of these compounds being homogeneous, compared with chemical cleaning. The protein and lipid contents were in the surface layer, whereas sugars were located in the innermost part that contributes to the Maillard reaction during fouling formation. After enzymatic cleaning, the reduction in the concentration of Ca and P was 71.61 and 74.67%, respectively, compared with fouling intact. Thus, enzymatic cleaning, without the accumulation of Na from chemical cleaning, leaves 1.5 times less mineral than chemical cleaning. Knowing the content and structure of fouling in the industry helps to formulate better products to achieve proper levels of cleanliness. Additionally, studying the cleaning residues helps to avoid problems of cross-contamination between batches or subsequent microbial growths (biofilms) on surfaces with residues.

Biofilms in the Spotlight: Detection, Quantification, and Removal Methods.

Microorganisms can colonize and subsequently form biofilms on surfaces, which protect them from adverse conditions and make them more resistant than their planktonic free-living counterparts. This is a major concern in the food industry because the presence of biofilms has significant implications for microbial food contamination and, therefore, for the transmission of foodborne diseases. Adequate hygienic conditions and various preventive and control strategies have consequently been developed to ensure the provision of safe, good-quality food with an acceptable shelf-life. This review focuses on the significance of biofilms in the food industry by describing the factors that favor their formation. The interconnected process among bacteria known as "quorum sensing," which plays a significant role in biofilm development, is also described. Furthermore, we discuss recent strategic methods to detect, quantify, and remove biofilms formed by pathogenic bacteria associated with food processing environments, focusing on the complexity of these microbial communities.

Bactericidal Efficacy of Hydrogen Peroxide-Based Disinfectants Against Gram-Positive and Gram-Negative Bacteria on Stainless Steel Surfaces.

In order to develop disinfectant formulations that leverage the effectiveness of hydrogen peroxide (H2 O2 ), this study evaluated the bactericidal efficacy of hydrogen peroxide-based disinfectants against Gram-positive and Gram-negative bacteria on stainless steel surfaces. Low concentration of hydrogen peroxide as 0.5% with a cationic polymer, ethoxylated fatty alcohol, and ethyl alcohol had bactericidal efficacy (reductions ≥ 4 log10 CFU/mL) against Escherichia coli, Staphylococcus aureus, Enterococcus hirae, and Pseudomonas aeruginosa. Hydrogen peroxide-based disinfectants were more effective against E. hirae and P. aeruginosa than to S. aureus. However, the efficacy of hydrogen peroxide against catalase positive bacteria such as S. aureus was increased when this compound was formulated with low concentrations of benzalkonium chloride or ethyl alcohol, lactic acid, sodium benzoate, cationic polymer, and salicylic acid. This study demonstrates that the use of hydrogen peroxide with other antimicrobial products, in adequate concentrations, had bactericidal efficacy in Gram-positive and Gram-negative bacteria on stainless steel surfaces, enabling to reduce the effective concentration of hydrogen peroxide. In the same way, the use of hydrogen peroxide-based disinfectants could reduce the concentrations of traditional disinfectants as quaternary ammonium compounds and therefore a reduction of their chemical residues in the environment after being used. PRACTICAL APPLICATION: The study of the bactericidal properties of environmentally nontoxic disinfectants such as hydrogen peroxide, sole or in formulations with other disinfectants against Gram-positive and Gram-negative bacteria can enhance the efficacy of various commonly used disinfectant formulations with the hygiene benefits that it entails. Also, the use of hydrogen peroxide formulations can reduce the concentration levels of products that generate environmental residues.

Urticaria crónica asociada a Helicobacter pylori / Chronic urticaria associated with Helycobacter pylori

Se efectuó un estudio descriptivo y prospectivo de 51 pacientes con diagnóstico de urticaria crónica, atendidos en la consulta de Dermatología del Hospital General Docente Dr Juan Bruno Zayas Alfonso de Santiago de Cuba, durante el primer semestre del 2008, para identificar las causas de dicha afección. Se utilizó el porcentaje como medida de resumen y la prueba del Ji al cuadrado, considerando su significación cuando p <0,05. En la casuística predominó el sexo femenino y se encontró una positividad de Helicobacter pylori en las biopsias gástricas realizadas.

A descriptive and prospective study was carried out in 51 patients diagnosed with chronic urticaria, who were attended at the Outpatient Dermatology Department of Dr Juan Bruno Zayas Alfonso Teaching General Hospital of Santiago de Cuba during the first semester of 2008 to identify the etiology of this condition. The percentage as a summary measure and the chi-square test were used, considering their significance when p <0, 05. Female sex prevailed in the case material and Helicobacter pylori-positive gastric biopsies were found.

Caracterización de pacientes con acalasia en el nivel secundario de atención / Characterization of patients with achalasia in the second level care

Se realizó uno estudio descriptivo, prospectivo y transversal en 31 pacientes con diagnóstico de acalasia, atendidos en el Servicio de Gastroenterología del Hospital General Docente Dr Juan Bruno Zayas Alfonso de Santiago de Cuba desde julio del 2006 hasta septiembre del 2007. Entre los principales resultados sobresalieron el predominio del sexo femenino, de los hábitos tóxicos como factores de riesgo, de la hernia hiatal y de la disfagia, así como la pérdida de peso. Se utilizó el porcentaje como medida de resumen y la prueba del Ji al cuadrado en aquellas tablas donde hubo condiciones para su aplicación, considerando su significación cuando p< 0,05.

A descriptive, prospective and cross-sectional study was carried out in 31 patients with diagnosis of achalasia, assisted in the Service of Gastroenterology of Dr Juan Bruno Zayas Alfonso Teaching General Hospital of Santiago de Cuba from July, 2006 to September, 2007. Among the main results the most important were the prevalence of the female sex, of toxic habits as risk factors, of hiatal hernia and of dysphagia, as well as the loss of weight. The percentage was used as summary measure and the X2 test in those charts where there were conditions for their application, taking into account their significance when p 0,05.

Evaluación de la polipectomía endoscópica del colon / Evaluation of colon endoscopic polypectomy

Se hizo un estudio descriptivo, transversal y prospectivo de los 33 pacientes con pólipos colónicos diagnosticados y extirpados en el Servicio de Gastroenterología del Hospital General Dr Juan Bruno Zayas Alfonso de Santiago de Cuba, desde marzo del 2006 hasta septiembre del 2007. En la casuística primaron el sexo femenino, las personas mayores de 55 años, los adenomas localizados en el recto, así como los pólipos únicos y sésiles (de de 0,5-1 cm de tamaño). Se presentaron escasas complicaciones.

A descriptive, cross-sectional and prospective study was conducted in 33 patients with colonic polyps diagnosed and removed in the Gastroenterology Service of Dr Juan Bruno Zayas Alfonso General Hospital of Santiago de Cuba, from March, 2006 to September, 2007. Female sex, people older than 55 years of age, rectal adenomas, as well as unique and sessile polyps (0,5-1cm size) prevailed in the case material. There were very few complications.

Observaçöes / A study

Estudou-se em laboratório a influência de duas diferentes fontes de alimentaçÝo sobre oviposiçÝo, eclosÝo dos ovos e tempo de vida de casais de Triatoma matogrossensis. Foram observados 68 casais separados em quatro diferentes grupos, com 20, 12, 20 e 16 casais, respectivamente. Os grupos Al e A2 foram alimentados em pombos e os grupos C1 e C 2 em coelhos. Os casais foram mantidos em estufa a 26§ñ 2§C e UR de 60-80 por cento, com fotoperíodo de 14 horas. O maior número de ovos postos foi encontrado no grupo Al. NÝo houve diferença na proporçÝo de ovos eclodidos dos grupos alimentados em coelhos ou pombos. NÝo foram observadas diferenças de tempo de vida entre machos e fêmeas dos quatro grupos, entretanto o grupo A1 apresentou o maior tempo de sobrevivência e o grupo C2 o menor

Leishmaniasis cutánea difusa: primer reporte de un caso parasitológicamente confirmado en el Ecuador

En el texto, se reporta por primera vez un caso parasitológicamente confirmado de leishmaniasis cutánea difusa en el Ecuador. El paciente fue seguido por más de 4 años y se realizaron exhautivos exámenes clínicos y de laboratorio, a fin de confirmar esta forma clínica de la enfermedad (leishmaniasis). La anergia al antígeno Leishmania y la respuesta refractaria a la quimioterapia fueron claramente demostradas. El parásito aislado fue identificado como Leishmania mexicana, por medio de análisis de karyodeme y zymodeme.