Simulation of the Physiological Characteristics of Pillar and Modiolar Fibers of the Auditory Nerve.

The study of the physiological characteristics of the auditory nerve fibers is fundamental to understand their capability to encode sounds. These characteristics include their spontaneous firing rate, their threshold, and their dynamic range. Although it is possible to perform in vitro recordings of these characteristics in different cell models, it is complicated to obtain in vivo measurements of them directly from the cochlea. For example, the apex of the cochlea since it is an unreachable region which is vulnerable to surgical trauma that could result in altered recordings. In this paper, the behavior of Pillar and Modiolar fibers of the auditory nerve were simulated in response to tone bursts of different frequencies and intensities. The proposed model allowed us to associate the basal firing rates with the physiological characteristics of the different auditory nerve fibers. This is especially important since some noise-associated hearing losses, such as acoustic trauma, have been explained as selective fiber damages.Clinical Relevance- Models that describe the properties of auditory nerve fibers are important to study specific aspects of maturation as well as the causes of sensorineural hearing loss in humans.

Hydroxyapatite extraction from fish scales of Tilapia.

Hydroxyapatite is the inorganic component of human bones. To be used for bone replacements, hydroxyapatite can be synthesized or extracted from natural components. In this work we present the hydroxyapatite extraction from fish scales of the same Orechromis family (Tilapia) but from two different species usually consumed in Mexico and in Spain. Our results indicate, for both species, that it is possible to obtain hydroxyapatite, and moreover, that this biomaterial is enriched with magnesium for the Mexican Oreochromis hunteri, and with aluminum for the Spanish Oreochromis niloticus.

Human textiles: A cell-synthesized yarn as a truly "bio" material for tissue engineering applications.

In the field of tissue engineering, many groups have come to rely on the extracellular matrix produced by cells as the scaffold that provides structure and strength to the engineered tissue. We have previously shown that sheets of Cell-Assembled extracellular Matrix (CAM), which are entirely biological yet robust, can be mass-produced for clinical applications using normal, adult, human fibroblasts. In this article, we demonstrate that CAM yarns can be generated with a range of physical and mechanical properties. We show that this material can be used as a simple suture to close a wound or can be assembled into fully biological, human, tissue-engineered vascular grafts (TEVGs) that have high mechanical strength and are implantable. By combining this truly "bio" material with a textile-based assembly, this original tissue engineering approach is highly versatile and can produce a variety of strong human textiles that can be readily integrated in the body. STATEMENT OF SIGNIFICANCE: Yarn of synthetic biomaterials have been turned into textiles for decades because braiding, knitting and weaving machines can mass-produce medical devices with a wide range of shapes and mechanical properties. Here, we show that robust, completely biological, and human yarn can be produced by normal cells in vitro. This yarn can be used as a simple suture material or to produce the first human textiles. For example, we produced a woven tissue-engineered vascular grafts with burst pressure, suture retention strength and transmural permeability that surpassed clinical requirements. This novel strategy holds the promise of a next generation of medical textiles that will be mechanically strong without any foreign scaffolding, and will have the ability to truly integrate into the host's body.

Biomateriales para Regeneración de Tejido Óseo Extraídos de Desechos de Pescado / Biomaterials for Bone Tissue Regeneration Extracted from Fish Wastes

Resumen Los biomateriales para regeneración ósea comúnmente se basan en el diseño natural del hueso, el cual mezcla la dureza de un material cerámico como la hidroxiapatita con la flexibilidad de un polímero como el colágeno. Ambos materiales pueden extraerse de los desechos del pescado consumido en la dieta humana, tales como escamas, piel e incluso huesos. Esta extracción tiene la ventaja de aportar biomateriales naturales, de baja toxicidad y como añadido, que evitan la transmisión de enfermedades que se ha reportado para colágenos provenientes de animales mamíferos. En este trabajo se hace una revisión de bibliografía referente a la extracción de colágeno tipo I, precursores de hidroxiapatita y síntesis de compósitos de ambos, para proponer la recuperación de estos biomateriales como una alternativa amigable con el ambiente y útil para usos médicos.

Abstract Biomaterials for bone tissue regeneration are commonly based in the natural design of bone where the stiffness of a ceramic material as hydroxyapatite is combined with the flexibility of a polymer such as collagen. Both materials can be extracted from human consumed fish waste, such as scales, bones and skin. The recovery of these biomaterials from fish waste has the advantage of yielding natural materials of low toxicity, avoiding the possible disease transmission found for the collagen coming from mammalians. In this article, we review several reports about collagen type I and hydroxyapatite precursors extraction, and composite synthesis, from fish waste in order to propose these methods as a green alternative for biomaterials useful for medical purposes.

A modelling study of glycolytic oscillations and electrical activity in pancreatic alpha cells / Un estudio de las oscilaciones glicolíticas y la actividad eléctrica en un modelo de célula alfa de páncreas

Abstract Pancreatic alpha and beta cells release the main hormones involved in blood glucose regulation: glucagon and insulin, respectively. Based on the observation that metabolic oscillations are related to electrical activity and, in turn, to insulin secretion in beta cells, in the present work we use a mathematical modelling approach to explore the contribution of glycolytic oscillations to electrical activity in alpha cells. Due to lack of data about metabolism in alpha cells and taking into account that pancreatic cells comes from a common progenitor, we used a previous model of pancreatic beta cells and focus on the main differences between both cell types. The main finding contrasts with beta cells since electrical activity in alpha cells could be triggered independently of glycolic oscillations. It suggests that alpha cells are stimulated by blood glucose through a different pathway, which is in agreement with the role of alpha cells during hypoglycemia.

Resumen Las células alfa y beta de páncreas secretan las dos hormonas más importantes para la regulación de la glucosa en sangre: el glucagón y la insulina, respectivamente. Dado que en células beta se ha observado la presencia de oscilaciones metabólicas relacionadas con su actividad eléctrica y, por tanto, con la secreción de insulina, en este trabajo se presenta un estudio de la posible relación entre las oscilaciones glicolíticas y la actividad eléctrica en células alfa mediante un enfoque de modelación matemática. Debido a la falta de información sobre el metabolismo en las células alfa y tomando en cuenta que las células pancreáticas provienen de un progenitor común, se utilizó un modelo previamente propuesto de células beta y se tomaron en cuenta las principales diferencias entre ambos tipos celulares para el análisis. Nuestros resultados muestran que, a diferencia de las células beta, la actividad eléctrica en células alfa puede dispararse independientemente de la presencia de oscilaciones glicolíticas, lo cual sugiere que estas células son estimuladas por la glucosa a través de una ruta metabólica diferente a la propuesta para células beta, lo cual es congruente con su papel regulador durante periodos de baja glucosa.

Simulation of the efficiency of inner hair cell secretion in the auditory pathway.

Sound coding involves several stages of processing along the auditory path. Specifically, the Inner Hair Cells (IHC) act as sensory receptors and transduce acoustic information -frequency, intensity and duration of the stimulus- into neuronal signals. In this work, a stochastic model was implemented to achieve a better understanding of the IHC-auditory nerve synapse, specifically, the process of Ready Releasable Pool (RRP) vesicle exocytosis, a complicated process to study experimentally because current protocols do not provide adequate temporal resolution, in the order of milliseconds. The presented model allows predicting the efficiency of glutamate release towards explaining maturation changes or disease impacts in the auditory pathway.

Unidad del paciente crónico - Programa PRINCEP / Chronic patient unit - PRINCEP program

No disponible

Reporte de caso y revisión de la literatura de caso de paciente con meningoencefalitis por amebas de vida libre / Case report and literature review of a patient with meningoencephalitis from free-living amoebae

Paciente de 14 años, proveniente de Apartadó (Antioquia), remitido al Hospital Pablo Tobón Uribe de Medellín por un cuadro febril agudo asociado a deterioro rápido del estado de conciencia, decantándose posteriormente como causa de su deterioro una ameba de vida libre (Naegleria fowleri) . Las amebas de vida libre son una causa etiológica poco común de meningitis, tienen un curso fulminante y requieren de un alto índice de sospecha para hacer un tratamiento oportuno.

A 14-year-old patient from Apartado (Antioquia, Colombia) was referred to Hospital Pablo Tobon Uribe in Medellin for acute febrile illness associated with headache and rapid loss of consciousness. The etiologic agent causing this deterioration was found to be a free-living amoeba ( Naegleria fowleri ). Free-living amoebae are a rare etiology for meningoencephalitis, have a fulminant course and require a high index of suspicion for early diagnosis.

Tissue transglutaminase is a negative regulator of monomeric lacritin bioactivity.

PURPOSE: Molar accounting of bioactive fluids can expose new regulatory mechanisms in the growing proteomic focus on epithelial biology. Essential for the viability of the surface epithelium of the eye and for normal vision is the thin, but protein-rich, tear film in which the small tear glycoprotein lacritin appears to play a prominent prosecretory, cytoprotective, and mitogenic role. Although optimal bioactive levels in cell culture are 1 to 10 nM over a biphasic dose optimum, ELISA suggests a sustained tear lacritin concentration in the midmicromolar range in healthy adults. Here we identify a reconciling mechanism. METHODS: Monoclonal anti-lacritin 1F5 antibody was generated, and applied together with a new anti-C-terminal polyclonal antibody to tear and tissue Western blotting. In vitro tissue transglutaminase (Tgm2) cross-linking was monitored and characterized by mass spectrometry. RESULTS: Blotting for lacritin in human tears or saliva surprisingly detected immunoreactive material with a higher molecular weight and prominence equal or exceeding the ∼23 to 25 kDa band of monomeric glycosylated lacritin. Exogenous Tgm2 initiated lacritin cross-linking within 1 minute and was complete by 90 minutes-even with as little as 0.1 nM lacritin, and involved the donors lysine 82 and 85 and the acceptor glutamine 106 in the syndecan-1 binding domain. Lacritin spiked into lacritin-depleted tears formed multimers, in keeping with ∼0.6 µM TGM2 in tears. Cross-linking was absent when Tgm2 was inactive, and cross-linked lacritin, unlike recombinant monomer, bound syndecan-1 poorly. CONCLUSIONS: Since syndecan-1 binding is necessary for lacritin mitogenic and cytoprotective activities, TGM2 cross-linking negatively regulates lacritin bioactivity.

The value of animal movement tracing: a case study simulating the spread and control of foot-and-mouth disease in California.

The purpose of this study was to estimate the benefits of an electronic animal tracing system and an improved paper-based system in terms of the potential spread of foot-and-mouth disease (FMD) if introduced in California. A spatial, stochastic simulation model and data for California were used to simulate FMD outbreaks originating from a dairy herd as the index case (IC). Descriptive statistics of the simulated FMD outbreak extent and duration were examined to determine the benefit of an electronic system or paper-based tracing systems of varying efficacies. According to the simulations, an electronic tracing system would reduce the median number of infected premises (IPs) by 8-81%, depending on size of the IC herd compared with the results expected from identifying IPs based on clinical signs alone. The benefit also varied by IP herd type, e.g. ≥ 50% for sheep farms, goat farms and calf and heifer raising operations and ≤ 20% for swine and beef premises. The electronic system simulated a decrease in the median duration from at least 200d to 42d, if the IC were a small dairy and from 110d to 45d if the IC were a large dairy. The impact of an introduction of FMD in California could be reduced substantially even without an electronic system, if paper-based tracing were more efficient; however, these benefits are far less than those that could be realized from an electronic animal identification system. Results show that substantial benefits, in terms of fewer IPs and infected animals and reduced epidemic duration, may be realized as a result of an efficient electronic animal identification system, compared with a paper-based animal tracing system; however, until then, an improvement in the current system, especially regarding the ability to trace movements the day prior to a premises being diagnosed with FMD, may be highly beneficial.

Preventive and curative importance of the baropodometric analysis for ergonomics and occupational health.

The pressure distribution on the plantar surface may reveal information not only about the feet structure, also it may bring out information about the entire body posture not only on health but also pathologic conditions. The application in ergonomics and occupational health gives access to the postural correction that on a long term may provoke professional injuries giving presition and security. This study is on 132 workers of Universidad de las Américas.

Ergonomic and individual risk evaluation.

The ergonomic risks constitute a vital aspect of study and prevention for the worker's health, especially for people with different capacities. Very job has and implies certain type of risk for the worker's health, depending on the conditions it is done with the use of tools or without them. Aplicated techniques: posturogram, baropodometry, Schober test, biocinemátic chain test, Fukuda test, propioceptiva plataform in personnel with special capabilities.

Hemiartroplastia fallida por ruptura del tallo femoral: reporte de dos casos / Failled hip hemiarthroplasty as a result of breakage: report of two cases

La hemiartroplastia de cadera constituye una opción terapéutica en el manejo de las fracturas intracapsulares de cadera en pacientes ancianos, especialmente en aquellos con comorbilidades y poca demanda funcional. Se trata de un procedimiento que, como cualquier otro, no está exento de riesgos tales como el sangrado, la infección, la luxación, el protrusio acetabular y, menos frecuente, la ruptura del implante. De esta complicación existen pocos casos reportados en la literatura. En este artículo se reportan dos casos de pacientes tratados en el Hospital San Vicente de Paúl con falla de hemiartroplastia por ruptura de tallo femoral y se presenta una revisión de la literatura pertinente sobre el tema.

Self-esteem, confidence and relationship satisfaction in men with erectile dysfunction: a randomized, parallel-group, double-blind, placebo-controlled study of sildenafil in Mexico.

Erectile dysfunction (ED) negatively impacts self-esteem and relationship satisfaction. The Self-Esteem and Relationship (SEAR) questionnaire is a validated, ED-specific, patient-reported instrument that specifically addresses self-esteem and relationship issues within the context of ED. Effective ED treatment with sildenafil in a double-blind, placebo-controlled clinical trial conducted in Brazil, Mexico, Australia and Japan showed pooled cross-cultural improvements in self-esteem, confidence and relationship satisfaction. This report focuses on the results from the subgroup of men from nine Mexican centers who participated in the multinational study. A total of 95 men aged >or=18 years with clinically diagnosed ED and currently in a stable relationship were randomized to placebo (n=47) or sildenafil (n=48). The SEAR results for Mexican men showed that sildenafil treatment led to significant improvements in self-esteem, confidence and relationship satisfaction. These data support an earlier study showing that Latin American men taking sildenafil have similar safety and efficacy profiles compared to non-Latin counterparts.

[Effectiveness of the topical application of fluor on the moderate gingivitis in diabetic type 2]. / Eficacia de la aplicación tópica de flúor sobre la gingivitis moderada en diabéticos tipo 2.

OBJECTIVE: To evaluate the efficiency of the fluor topic application vs. oral washing gel in diabetic patients type 2 with moderate gingivitis. METHODS: Controlled clinical test double blind in a Primary Care Unit from February 2003 to May 2004. Both gender patients from 40 to 60 year old diagnosed with moderate gingivitis were included and randomly assigned to each group. Cherry flavored fluor gel and hygienic measures were applied to the cases during 10 consecutive days of treatment. Hygienic measures and oral washing gel were applied to the control group during 10 days. The relative risk and confidence interval of 95 %. RESULTS: The fluor group (n = 14) reported a greater efficacy than oral washing gel group at the end of the treatment. No adverse effects were found. CONCLUSIONS: The topic application of Fluor and hygienic measures were effective diminishing gingivitis without adverse effects and at a low cost.

The isolation of exotic Newcastle disease (END) virus from nonpoultry avian species associated with the epidemic of END in chickens in southern California: 2002-2003.

During the first 11 months of the 2002-2003 exotic Newcastle disease (END) epidemic in chickens in southern California, a total of 27,688 cloacal and tracheal (oropharyngeal) swab pools and/or tissue pools from 86 different avian species other than chickens and turkeys were submitted for Newcastle disease virus (NDV) isolation and characterization. Fifty-seven specimens (0.23%), representing 12 species of birds and 13 unspecified species, from a total of 24,409 accessions or submissions were positive for NDV. The NDV isolate was characterized as ENDV by real-time reverse transcription-polymerase chain reaction (RT-PCR). Of the 11,486 premises with other avian species, 1599 also had chickens. There were 1900 positive chicken samples from 164 premises, and 56 positive other avian species from 51 premises. Twelve premises had both positive chickens and positive other avian species. All positive other avian species were located on premises either on or within a 1 km radius of known infected premises. In this epidemic, premises with positive other avian species were significantly more likely to have chickens, and were significantly more likely to have positive chickens (OR = 3.7, P < 0.0001).

Información para la toma de decisiones en la planeación del desarrollo local / Information for making decisions in planning local development

Objetivo: establecer relaciones entre información y toma de decisiones en torno a la planificación del desarrollo local, estudiando los usos de información en un proceso de planeación territorial en un área de Cali, Colombia. Métodos: se realizaron entrevistas semiestructuradas, grupos focales y revisión documental. Se definieron 19 categorías de estudio mediante análisis deductivo e inductivo. Se realizó análisis horizontal y vertical de la información y se contrastaron fuentes y métodos. Se indagó sobre actores de las decisiones, tipos de información usada, tipos de uso, flujos y necesidades de información. Resultados: se identificaron valores subyacentes a la acción de los decisores, basados en sus percepciones. Se encontró que la información se considera como objeto que debe controlarse, que da poder. También se identificaron como determinantes de uso la información que desconoce necesidades comunitarias, el sentimiento de impotencia de las comunidades, la desconfianza en el proceso y en el gobierno y la visión sesgada de la planeación como asignación de dineros. Discusión: es pertinente establecer procesos de información que valoren, cualifiquen y complementen conocimientos comunitarios con mejoramiento de información institucional; que acerquen las comunidades al gobierno y a procesos políticos y que contribuyan al empoderamiento para una equitativa participación comunitaria en las decisiones de la planeación del desarrollo

Simulation of five intracellular C2+-regulation mechanisms in response to voltage-clamp pulses.

We report the simulation of five C2+ regulation mechanisms in response to voltage-clamp pulses applied at the membrane. We obtain the currents generated and also record the C2+ concentration changes in the whole cell during and after the pulse. Our simulator includes models for the L-type voltage-dependent C2+ channels, the C2+ pump, the Na+/C2+ exchanger and a fast buffering system, along with diffusion assuming a spheric cell shape.

Tratamiento estético integral del sector anterior de la boca / Comprehensive esthetic treatment of the anterior section of the mouth

Los diferentes elementos del rostro, ojos, nariz, labios, mentón, boca, etc., en forma aislada no determinan la belleza. La integración armónica de estos elementos son determinantes de la estética facial. Dentro de ellos, la boca juega un papel preponderante con una disposición, forma, tamaño y color de dientes adecuada, en relación con los márgenes gingivales y con los llamados puntos de referencia del rostro. El tener una agradable sonrisa y una buena apariencia en el momento de hablar, se ha convertido en una necesidad en la vida moderna, en el campo de las relaciones sociales, laborales y humanas en general. Se hace una revisión de las bases de la estética dental: 1) marco y puntos de referencia; 2) proporciones e idealismo; 3) simetría y 4) perspectiva e ilusión. Como parte de estas bases, se analizan los principios macro estéticos y micro estéticos. Finalmente, se presenta un caso clínico como aplicación de los fundamentos descritos

Bupivacaina simple al 0.25 por ciento y bipivacaina simple al 0.125 por ciento mas fentanyl, en analgesia epidural durante el trabajo de parto. Hospital General de Medellín Enero – Diciembre 1991 Enero – Abril 1992 / Bupivacaine simple to 0.25 and bupivacaine simple to 0.125 plus fentanyl, in epidural analgesia during labor work. Medellín General Hospital, January - December 1991 to January – April 1992

Se realizó un estudio experimental comparando dos esquemas terapéuticos de analgesia epidural durante el trabajo de parto, en el Hospital General de Medellín en el periodo enero – abril 1992. La población de estudio estuvo constituida por 92 pacientes de bajo riesgo obstétrico distribuidas al azar en dos grupos: control (marciana, 0.25 por ciento) y estudio (marciana al 0.125 por ciento más fentanyl). El 74 por ciento de las pacientes eran primigestantes y el 26 por ciento eran primigestantes y el 26 por ciento eran multigestantes. En cada una de ellas se evaluó el comportamiento hemodinámica (frecuencia cardiaca materna y presión arterial media materna) la velocidad de dilatación cervical, la presencia del bloqueo motor, la medición del dolor mediante escala visual análoga. En el recién nacido se determinó el Apgar al minuto y cinco minutos y los niveles de fentanyl en sangre del condón umbilical...