A chinrest-based approach to measure eye movements and experimental task engagement in macaques with minimal restraint.

BACKGROUND: The use of Rhesus macaques in vision research is crucial due to their visual system's similarity to humans. While invasive techniques have been the norm, there has been a shift towards non-invasive methods, such as facemasks and head molds, to enhance animal welfare and address ethical concerns. NEW METHOD: We present a non-invasive, 3D-printed chinrest with infrared sensors, adapted from canine research, allowing for accurate eye movement measurements and voluntary animal participation in experiments. RESULTS: The chinrest method showed a 16% and 28% increase in average trial numbers for Monkey 1 and Monkey 2, respectively, compared to the traditional headpost method. The engagement was high, with monkeys performing over 500 trials per session and initiating a new trial after an average intertrial interval of approximately 1 second. The hit rate improved by about 10% for Monkey 1 in the chinrest condition, and the fixation precision, measured by the standard deviation of gaze positions, was significantly better in the chinrest condition, with Monkey 1 showing a reduction in fixation imprecision from 0.26° to 0.17° in the X-axis. COMPARISON WITH EXISTING METHODS: The chinrest approach showed significant improvements in trial engagement and reduction in aborted trials due to fixation breaks, indicating less stress and potentially improved data quality compared to previous non-invasive methods. CONCLUSIONS: The chinrest method offers a significant advancement in primate cognitive testing by allowing for precise data collection while addressing animal welfare concerns, possibly leading to better scientific outcomes and a paradigm shift in primate research methodologies.

Keeping time and rhythm by internal simulation of sensory stimuli and behavioral actions.

Effective behavior often requires synchronizing our actions with changes in the environment. Rhythmic changes in the environment are easy to predict, and we can readily time our actions to them. Yet, how the brain encodes and maintains rhythms is not known. Here, we trained primates to internally maintain rhythms of different tempos and performed large-scale recordings of neuronal activity across the sensory-motor hierarchy. Results show that maintaining rhythms engages multiple brain areas, including visual, parietal, premotor, prefrontal, and hippocampal regions. Each recorded area displayed oscillations in firing rates and oscillations in broadband local field potential power that reflected the temporal and spatial characteristics of an internal metronome, which flexibly encoded fast, medium, and slow tempos. The presence of widespread metronome-related activity, in the absence of stimuli and motor activity, suggests that internal simulation of stimuli and actions underlies timekeeping and rhythm maintenance.

Optogenetic stimulation of the primary visual cortex drives activity in the visual association cortex.

Developing optogenetic methods for research in non-human primates (NHP) is important for translational neuroscience and for delineating brain function with unprecedented specificity. Here we assess, in macaque monkeys, the selectivity by which optogenetic stimulation of the primary visual cortex (V1) drives the local laminar and widespread cortical connectivity related to visual perception. Towards this end, we transfected neurons with light-sensitive channelrhodopsin in dorsal V1. fMRI revealed that optogenetic stimulation of V1 using blue light at 40 Hz increased functional activity in the visual association cortex, including areas V2/V3, V4, motion-sensitive area MT and frontal eye fields, although nonspecific heating and eye movement contributions to this effect could not be ruled out. Neurophysiology and immunohistochemistry analyses confirmed optogenetic modulation of spiking activity and opsin expression with the strongest expression in layer 4-B in V1. Stimulating this pathway during a perceptual decision task effectively elicited a phosphene percept in the receptive field of the stimulated neurons in one monkey. Taken together, our findings demonstrate the great potential of optogenetic methods to drive the large-scale cortical circuits of the primate brain with high functional and spatial specificity.

Impacto de la metodología de debate como técnica de enseñanza- aprendizaje en población universitaria

El objetivo principal de la presente investigación es determinar la influencia entre las habilidades de pensamiento crítico, técnicas de oratoria y argumentación en las dinámicas de debates en el ámbito educativo, las cuales integran dentro de sus ambientes y herramientas de aprendizaje grupos de debates y el desarrollo de procesos cognitivos de orden superior. La metodología utilizada fue de corte mixta. Dentro de los resultados, existen hallazgos significativos que avalan el desarrollo de destrezas en la metodología de debate, permitiendo concluir su influencia en la potenciación de habilidades cognoscitivas, interpersonales y académicas.

The main objective of the present research is to determine the influence between critical thinking skills, public speaking techniques, and argumentation on the dynamics of debates in the educational environment, which integrate within their environments and learning tools debate groups and the development of higher order cognitive processes. The methodology used was mixed. Within the results, there are significant findings that support the development of skills in the debate methodology, by allowing to conclude its influence on the enhancement of cognitive, interpersonal, and academic skills.

Synthesis of graphene oxide from agave fiberTequilana Weberby hydrothermal method.

Lignocellulosic residues are an important biomass source in Mexico, which can be considered as starting materials for obtaining carbon materials. In this work, carbon materials were produced by pyrolysis of agave fiber (AF). The results obtained revealed that the hydrothermal process was successfully used for the synthesis of carbon fibers and subsequently potentiate the production of graphite sheets and graphene oxide (GO), after determining and optimizing the reaction conditions. The formation of graphite and GO was indicated by XRD, Raman spectroscopy and TGA thermal analysis, the latter evaluated the carbon oxidation range. Scanning electron microscope showed the samples morphology and microstructure of the AFTequilana Weberand the synthesized products (Graphite-600 °C, GO-800 °C and GO-1000 °C), being all of them carbon allotropes, they presented size and variable thickness, with potential surface characteristics useful in various industrial applications. The hydrothermal and thermal processes were considered an economic and environmental way of obtaining materials under inert conditions, especially to produce GO, which is a material that has many useful properties and a plethora of new applications, like a more affordable support for catalysts, absorbent, semiconductor.

Seudoartrosis del escafoides: experiencia con injerto óseo vascularizado del primer metacarpiano. Serie de casos / Scaphoid pseudoarthrosis: experience with vascularized bone graft of the first metacarpal. Case series

Introducción describir los resultados clínicos, funcionales y radiológicos de pacientes con seudoartrosis de fractura del escafoides, sometidos a cirugía con la técnica de Bertelli. en un centro de cuarto nivel de complejidad. Materiales & Métodos Serie de casos en un centro de cuarto nivel de complejidad entre el 2005 y 2016 de pacientes con fractura de escafoides en seudoartrosis sometidos a cirugía de revisión con injerto vascularizado de la primera arteria dorsal metacarpiana según la técnica de Bertelli. Se tomaron datos de historias clínicas, que se analizaron con medidas descriptivas de resumen. Resultados se analizaron 11 pacientes con una edad promedio de 30,1 años. El 72,7% fue llevado a osteosíntesis como manejo inicial. El procedimiento de revisión se realizó en una mediana de 380 días. Se reportaron complicaciones pos-quirúrgicas: necrosis del injerto en un paciente, necesidad de re-intervención en cuatro y no hubo infecciones. En el 72,7% se observó consolidación de la fractura y ocurrió en promedio a los 7,6 meses. La mitad de los pacientes tuvieron un puntaje DASH de 9 o menos y reportaron percepción de dolor leve - moderado el 90,9%. La mediana de seguimiento fue 14 meses. Discusión la ventaja de esta técnica es su reproducibilidad y versatilidad, pues su pedículo vascular constante y de buena longitud, permite utilizarse por un abordaje dorsal o palmar y para no consolidaciones del polo proximal, cintura o polo distal del escafoides. Este estudio mostró buenos resultados clínicos y funcionales, asociados a una baja tasa de complicaciones. Nivel de evidencia IV

Background The aim of study is to describe the clinical, functional, and radiological results in patients with pseudoarthrosis of scaphoid fractures who that underwent surgery using Bertelli's et al. technique. Methods Case series of patients with nonunion of scaphoid fractures in a high complexity care center between 2005 and 2016, who underwent revision surgery with vascularized bone graft of the first metacarpal dorsal artery according to Bertelli's et al. technique. Data were collected from clinical records, and it waswere analyzed using descriptive summary measures. Results The analysis included 11 patients with a mean age of 30,1 years (S.D: 9). 72,7% of the patients underwent conventional osteosynthesis as the initial approach. The revision surgery was performed with a median of 380 days (interquartile range: 194-470); there were no intraoperative complications. Post- surgery complications, such as graft necrosis, were reported in a one patient (9,1%), the need of for re-intervention in four patients and there were no infection related complications. Fracture union was seen in 72,7% patients in a mean of 7,6 months (S.D: 2,9) after the intervention. Half of the patient had a DASH score of 9 points or less. 54,5 reported pain as mild, 36,4% as moderate and without pain 9,1%. The median follow up period was 14 months and only one patient developed carpal arthritis. Discussion The advantage of this surgical technique is its reproducibility and versatility, thanks due to the constant and long vascular pedicle; this allows using dorsal or palmar approaches, as well as for the management of scaphoid nonunions of the proximal pole, waist, or distal pole. This study shows good clinical and functional results outcomes with a low rate of complications. Evidence Level IV

Out-of-pocket expenditures for HIV in the Dominican Republic: findings from a community-based participatory survey.

OBJECTIVES: The aim of this study was to estimate out-of-pocket expenditures incurred by individuals with HIV in the Dominican Republic. The study utilized different definitions and components for these expenditures and differentiated the results by wage ranges. METHODS: Data was obtained from an in-person survey of people living with HIV. The study was developed and implemented in collaboration with Dominican grassroots organizations and networks of people with HIV, through a process of community-based participatory research. RESULTS: The mean HIV-related expenditure reported by individuals in the sample in the last six months prior to the survey was in US$ 181; 15.4% of this total was spent for transportation and housing and costs to access the HIV facility. The mean expenditure reported by individuals for their current visit to an HIV center was US$ 10. These out-of-pocket expenditures exhibited regressivity, with lower-wage patients spending proportionally more to receive care. The results highlight the importance of considering other resources required to access treatment, such as lodging expenses and the time needed to travel to an HIV center and then to wait to be seen by a care provider. CONCLUSIONS: There should be more focus on expenditures made directly by people with HIV in the Dominican Republic so that these payments do not become a barrier to accessing health care. Using a community-based participatory design can ensure that such data can be leveraged to address the specific barriers to care that are faced by individuals with HIV.

Out-of-pocket expenditures for HIV in the Dominican Republic: findings from a community-based participatory survey Claire

[ABSTRACT]. Objectives. The aim of this study was to estimate out-of-pocket expenditures incurred by individuals with HIV in the Dominican Republic. The study utilized different definitions and components for these expenditures and differentiated the results by wage ranges. Methods. Data was obtained from an in-person survey of people living with HIV. The study was developed and implemented in collaboration with Dominican grassroots organizations and networks of people with HIV, through a process of community-based participatory research. Results. The mean HIV-related expenditure reported by individuals in the sample in the last six months prior to the survey was in US$ 181; 15.4% of this total was spent for transportation and housing and costs to access the HIV facility. The mean expenditure reported by individuals for their current visit to an HIV center was US$ 10. These outof- pocket expenditures exhibited regressivity, with lower-wage patients spending proportionally more to receive care. The results highlight the importance of considering other resources required to access treatment, such as lodging expenses and the time needed to travel to an HIV center and then to wait to be seen by a care provider. Conclusions. There should be more focus on expenditures made directly by people with HIV in the Dominican Republic so that these payments do not become a barrier to accessing health care. Using a community-based participatory design can ensure that such data can be leveraged to address the specific barriers to care that are faced by individuals with HIV.

[RESUMO]. Objetivos. Estimar as despesas desembolsadas por pessoas com HIV na República Dominicana segundo diferentes definições e itens para estas despesas e a diferenciação dos resultados por faixas salariais. Métodos. Os dados foram obtidos em uma pesquisa presencial com pessoas com HIV. O estudo foi elaborado e executado em colaboração com organizações locais dominicanas e redes de pessoas com HIV por meio de um processo da pesquisa participativa baseada na comunidade. Resultados. A despesa média relacionada ao HIV nos seis meses anteriores à pesquisa informada pelos participantes na amostra estudada foi de US$ 181, sendo que 15,4% deste montante foram gastos com transporte e moradia e custos de acesso ao serviço de HIV. A despesa média informada pelos participantes para a consulta corrente ao centro de assistência de HIV foi de US$ 10. A despesa desembolsada apresentou regressividade, com os pacientes pertencentes à faixa de menor salário gastando proporcionalmente mais para obter atendimento. Estes resultados indicam a importância de considerar outros recursos necessários para obter acesso ao tratamento, como despesas de alojamento e o tempo necessário para ir a um centro de assistência de HIV e aguardar o atendimento por um profissional. Conclusões. É preciso atentar mais às despesas incorridas diretamente pelas pessoas com HIV para que estes gastos não se convertam em barreiras ao acesso à assistência de saúde na República Dominicana. O design participativo baseado na comunidade do estudo permite que os dados sejam aproveitados para examinar as barreiras específicas ao atendimento de saúde enfrentadas por pessoas com HIV.

[RESUMEN]. Objetivos. El objetivo de este estudio fue estimar los gastos directos de bolsillo que enfrentan las personas con VIH en la República Dominicana, utilizando diferentes definiciones y componentes para estos gastos y desglosando los resultados por rangos salariales. Métodos. Los datos se obtuvieron a partir de una encuesta presencial a personas con infección por el VIH. El estudio se llevó a cabo en colaboración con organizaciones comunitarias locales y redes de personas con infección por el VIH, mediante un proceso de investigación participativa comunitaria. Resultados. El gasto directo promedio en los seis meses anteriores a la encuesta para las personas con VIH que conformaban la muestra fue de US$ 181; el 15,4% del gasto directo total se dedicó a transporte, vivienda y otros costos para acceder al establecimiento de salud. El gasto promedio informado por las personas para su cita actual en el establecimiento de salud fue de US$ 10. El gasto directo presentó regresividad: los pacientes de salario inferior gastaban proporcionalmente más para recibir atención. Los resultados destacan la importancia de considerar otros recursos necesarios para obtener acceso al tratamiento, como los gastos de alojamiento y el tiempo invertido en desplazarse a un centro de atención del VIH y esperar a ser atendido por un prestador de atención. Conclusiones. Es necesario centrar más la atención en el gasto directo de las personas con VIH en la República Dominicana, para que estos costos no se conviertan en un obstáculo al acceso a la atención de salud. Un enfoque participativo comunitario propiciaría el uso de estos datos para abordar los obstáculos específicos que enfrentan las personas con VIH a la hora de obtener atención.

Entrainment and maintenance of an internal metronome in supplementary motor area.

To prepare timely motor actions, we constantly predict future events. Regularly repeating events are often perceived as a rhythm to which we can readily synchronize our movements, just as in dancing to music. However, the neuronal mechanisms underlying the capacity to encode and maintain rhythms are not understood. We trained nonhuman primates to maintain the rhythm of a visual metronome of diverse tempos and recorded neural activity in the supplementary motor area (SMA). SMA exhibited rhythmic bursts of gamma band (30-40 Hz) reflecting an internal tempo that matched the extinguished visual metronome. Moreover, gamma amplitude increased throughout the trial, providing an estimate of total elapsed time. Notably, the timing of gamma bursts and firing rate modulations allowed predicting whether monkeys were ahead or behind the correct tempo. Our results indicate that SMA uses dynamic motor plans to encode a metronome for rhythms and a stopwatch for total elapsed time.

Controversia en el tratamiento de la lesión intraepitelial escamosa de alto grado (NIC II) / Controversy in the treatment of high-grade squamous intraepithelial lesion (CIN II)

Contexto: el cono LLETZ actualmente es el tratamiento de las NIC de alto grado. La resistencia al procedimiento es argumentada por los efectos del sobretratamiento (estenosis e insuficiencia cervical), sobre todo cuando se utilizan métodos ablativos destructivos en lugar de la resección quirúrgica ambulatoria (LLETZ). Objetivo: analizar el diagnóstico y tratamiento del NIC II mediante cono y legrado en pacientes que acuden al servicio de Patología del tracto genital inferior del Hospital Oncológico SOLCA-Quito Ecuador. Sujetos y métodos: en este estudio epidemiológico descriptivo observacional de corte transversal se analizaron expediente clínicos de 820 pacientes con diagnóstico histopatológico por biopsia de NIC II; mujeres entre 17 a 82 años que acudieron al servicio de patología del tracto genital inferior sujetas a control, en estas pacientes se realizó 530 legrados. El estudio fue realizado en el Hospital Oncológico SOLCA de Quito Ecuador, de los años 2004 a 2013. Resultados: la histopatología de los conos libres de neoplasia representa el 98,66% (n=809); existen 11 casos de neoplasias residuales (1,34%). El 53,7% de casos presenta una lesión igual o mayor que en biopsia, lo que justifica el cono. Conclusión: el procedimiento de cono LLETZ tiene gran utilidad diagnóstica, terapéutica y pronóstica en mujeres que presentan NIC II y otras patologías similares. (AU)

Background: the LLETZ cone is currently the treatment of high grade NICs. The resistance to the procedure is argued by the effects of overtreatment (stenosis and cervical insufficiency), especially when destructive ablative methods are used instead of ambulatory surgical resection (LLETZ). Objective: to analyze the diagnosis and treatment of CIN II by means of cone and curettage in patients attending the pathology department of the lower genital tract of the SOLCA-Quito Ecuador Oncology Hospital. Subjects and methods: in this cross-sectional descriptive epidemiological observational study, we analyzed clinical records of 820 patients with histopathological diagnosis by CIN II biopsy; women between 17 and 82 years old who visited the pathology service of the lower genital tract subject to control, in these patients 530 catheters were performed. The study was conducted at the SOLCA Oncology Hospital of Quito, Ecuador, from 2004 to 2013. Results: the histopathology of neoplasm-free cones represents 98.66% (n = 809); there are 11 cases of residual neoplasms (1.34%). 53.7% of cases present a lesion equal to or greater than in biopsy, which justifies the cone.(AU)

Meningococcal Neonatal Purulent Conjunctivitis/Sepsis and Asymptomatic Carriage of N. meningitidis in Mother's Vagina and Both Parents' Nasopharynx.

Neonatal conjunctivitis is usually associated with vagina's infection by Chlamydia sp., N. gonorrhoeae, and/or other bacteria during delivery. Meningococcal neonatal conjunctivitis is an extremely rare disease. We report a case of neonatal meningococcal sepsis/conjunctivitis and asymptomatic carriage of N. meningitidis from both parents (vagina and nasopharynx). As part of our active surveillance for meningococcal disease at the Tijuana General Hospital (TGH), Mexico, we identified a 3-day-old newborn with meningococcal conjunctivitis and sepsis. The patient had a one-day history of conjunctivitis and poor feeding. Clinical examination confirmed profuse purulent conjunctival discharge, as well as clinical signs and laboratory findings suggestive of bacteraemia. Gram stain from conjunctival exudate revealed intracellular Gram negative diplococci; we presumed the baby had gonorrheal conjunctivitis; however, serogroup Y, N. meningitidis was isolated both from conjunctival exudate and blood. Additionally, isolation of serogroup Y, N. meningitidis was obtained from mother's vagina and both parents' nasopharynx. The baby was treated with 7 days of IV ceftriaxone and discharged with no sequelae.

Investigation of novel crystal structures of Bi-Sb binaries predicted using the minima hopping method.

Semi-conducting alloys BixSb1-x have emerged as a potential candidate for topological insulators and are well known for their novel thermoelectric properties. In this work, we present a systematic study of the low-energy phases of 35 different compositions of BixSb1-x (0 < x < 1) at zero temperature and zero pressure. We explore the potential energy surface of BixSb1-x as a function of Sb concentration by using the ab initio minima hopping structural search method. Even though Bi and Sb crystallize in the same R3[combining macron]m space group, our calculations indicate that BixSb1-x alloys can have several other thermodynamically stable crystal structures. In addition to the configurations on the convex hull, we find a large number of metastable structures which are dynamically stable. The electronic band structure calculations of several stable phases reveal the presence of strong spin-orbit interaction leading to the Rashba-Dresselhaus spin-splitting of bands which is of great interest for spintronics applications. We also find an orthorhombic structure of BiSb in the Imm2 space group which exhibits signatures of type-II Weyl semimetal. Additionally, we have studied the thermoelectric properties of the selected structures. Regarding thermoelectric properties, we find that the compositions which crystallize in the rhombohedral structure exhibit values of the Seebeck coefficient and the power factor similar to that of Bi2Te3 at room temperature, while the theoretical maximum figure of merit (ZeT) is smaller than that of Bi2Te3. We observe enhancement in the thermopower with the increase in the strength of the Rashba-Dresselhaus spin-splitting effect.

Monkeys Share the Human Ability to Internally Maintain a Temporal Rhythm.

Timing is a fundamental variable for behavior. However, the mechanisms allowing human and non-human primates to synchronize their actions with periodic events are not yet completely understood. Here we characterize the ability of rhesus monkeys and humans to perceive and maintain rhythms of different paces in the absence of sensory cues or motor actions. In our rhythm task subjects had to observe and then internally follow a visual stimulus that periodically changed its location along a circular perimeter. Crucially, they had to maintain this visuospatial tempo in the absence of movements. Our results show that the probability of remaining in synchrony with the rhythm decreased, and the variability in the timing estimates increased, as a function of elapsed time, and these trends were well described by the generalized law of Weber. Additionally, the pattern of errors shows that human subjects tended to lag behind fast rhythms and to get ahead of slow ones, suggesting that a mean tempo might be incorporated as prior information. Overall, our results demonstrate that rhythm perception and maintenance are cognitive abilities that we share with rhesus monkeys, and these abilities do not depend on overt motor commands.

Novel phases of lithium-aluminum binaries from first-principles structural search.

Intermetallic Li-Al compounds are on the one hand key materials for light-weight engineering, and on the other hand, they have been proposed for high-capacity electrodes for Li batteries. We determine from first-principles the phase diagram of Li-Al binary crystals using the minima hopping structural prediction method. Beside reproducing the experimentally reported phases (LiAl, Li3Al2, Li9Al4, LiAl3, and Li2Al), we unveil a structural variety larger than expected by discovering six unreported binary phases likely to be thermodynamically stable. Finally, we discuss the behavior of the elastic constants and of the electric potential profile of all Li-Al stable compounds as a function of their stoichiometry.

Smell facilitates auditory contagious yawning in stranger rats.

Most vertebrates yawn in situations ranging from relaxation to tension, but only humans and other primate species that show mental state attribution skills have been convincingly shown to display yawn contagion. Whether complex forms of empathy are necessary for yawn contagion to occur is still unclear. As empathy is a phylogenetically continuous trait, simple forms of empathy, such as emotional contagion, might be sufficient for non-primate species to show contagious yawning. In this study, we exposed pairs of male rats, which were selected for high yawning, with each other through a perforated wall and found that olfactory cues stimulated yawning, whereas visual cues inhibited it. Unexpectedly, cage-mate rats failed to show yawn contagion, although they did show correlated emotional reactivity. In contrast, stranger rats showed auditory contagious yawning and greater rates of smell-facilitated auditory contagious yawning, although they did not show correlated emotional reactivity. Strikingly, they did not show contagious yawning to rats from a low-yawning strain. These findings indicate that contagious yawning may be a widespread trait amongst vertebrates and that mechanisms other than empathy may be involved. We suggest that a communicatory function of yawning may be the mechanism responsible for yawn contagion in rats, as contagiousness was strain-specific and increased with olfactory cues, which are involved in mutual recognition.

Maximum Heart Rate during exercise: Reliability of the 220-age and Tanaka formulas in healthy young people at a moderate elevation / Frecuencia cardíaca máxima en ejercicio: confiabilidad de las fórmulas de 220-edad y Tanaka en jóvenes saludables en altitud moderada

Background. The formulas to predict maximum heart rate have been used for many years in different populations. Objective. To verify the significance and the association of formulas of Tanaka and 220-age when compared to real maximum heart rate. Materials and methods. 30 subjects -22 men, 8 women- between 18 and 30 years of age were evaluated on a cycle ergometer and their real MHR values were statistically compared with the values of formulas currently used to predict MHR. Results. The results demonstrate that both Tanaka p=0.0026 and 220-age p=0.000003 do not predict real MHR, nor does a linear association exist between them. Conclusions. Due to the overestimation with respect to real MHR value that these formulas make, we suggest a correction of 6 bpm to the final result. This value represents the median of the difference between the Tanaka value and the real MHR. Both Tanaka (r=0.272) and 220-age (r=0.276) are not adequate predictors of MHR during exercise at the elevation of Bogotá in subjects of 18 to 30 years of age, although more study with a larger sample size is suggested.

Introducción. Las fórmulas que predicen la Frecuencia Cardíaca Máxima (FCM) han sido utilizadas desde hace varios años en diferentes poblaciones. Objetivo. Verificar la precisión de las fórmulas de Tanaka y 220-edad con respecto a la FCM real. Materiales y métodos. Se evaluaron 30 sujetos -22 hombres y 8 mujeres- entre 18 y 30 años de edad en cicloergómetro y se compararon estadísticamente las fórmulas con la FCM real. Resultados. Se demuestra que tanto Tanaka p=0,0026 como 220-edad p=0,000003 no predicen la FCM real ni existe una asociación lineal de estas. Conclusiones. Debido a la sobreestimación que realizan dichas fórmulas con Tanaka se sugiere realizar una corrección de 6 lpm al resultado final. Este valor representa la mediana de la diferencia de Tanaka con respecto a la FCM real: tanto Tanaka r=0,272 como 220-edad r=0,276 no son predictores adecuados entre sujetos de 18 a 30 años de edad de la FCM durante el ejercicio en la altura de Bogotá, aunque se sugiere realizar más estudios con una muestra mayor.

Cytoskeletal proteins F-actin and ß-dystrobrevin are altered by the cryopreservation process in bull sperm.

The cryopreservation process has an important impact on sperm structure and physiology. The negative effects have been mainly observed on the plasma membrane, which is directly stabilized by the cytoskeleton. Since cytoskeleton proteins are osmosensitive and thermosensitive, the aim of this study was to evaluate the damage caused to the bull sperm cytoskeleton by cryopreservation (freezing-thawing). Fresh and frozen-thawed bull semen samples were exposed to a treatment with the neutral detergent Brij 36-T. Electron microscopy evidenced important damages at the sperm perinuclear theca after the protein extraction protocol; the perinuclear theca was partially solubilized, the perinuclear theca substructure disappeared in the cryopreserved samples. Furthermore, the sperm head's shape was significantly altered on the cryopreserved samples. Fluorescence analysis showed a decrease of the intensity of actin and dystrobrevin on the frozen-thawed samples. Western blot assays revealed a stronger signal for actin and ß-dystrobrevin in the frozen-thawed sperm samples than in the fresh ones. Our results suggest that the cryopreservation process highly alters the sperm cytoskeleton stability, causing its proteins to become more fragile and therefore more susceptible to be extracted.

Involvement of the AATn polymorphism of the CNR1 gene in the efficiency of procedural learning in humans.

Procedural learning refers to the acquisition of motor skills and the practice that refines their performance. The striatum participates in this learning through a function regulated by endocannabinoid signaling and other systems. This study relates the efficiency in learning a procedural task with the AATn polymorphism of the CNR1 gene, which encodes for the CB1 receptor. The mirror-drawing star task was solved by 99 healthy young subjects in three trials. The sample was divided into high- and low-performance groups based on performance efficiency. AAT12/14 carriers were more frequent in the former group, while there were more AAT12/13 carriers in the latter, which also made more errors/min. Therefore, we characterized two efficiency phenotypes: high- vs. low-performers associated with the two AATn genotypes, AAT12/14 vs. AAT12/13. The findings suggest that AATn polymorphism modifies CNR1 translation, indicating a different modulation of CB1.

Punishment-induced fear modifies the daily course of yawning in rats.

A challenge in the study of yawning behavior is understanding the way external factors may modify it. This study investigated whether response-dependent punishment or random punishment decreased yawning by the application of buzzer noise paired with electric shocks in a high-yawning strain of Sprague-Dawley male rats. Yawn rate increased daily in response to the experimental cage, and also to the buzzer noise. Two alternate periods of no punishment and punishment were followed by a final period of buzzer noise occurring alone. Punishment did not diminish yawning significantly in either condition although the yawn rate increased in the following period of no punishment and in the buzzer-noise period, relative to the period of yawn-dependent punishment. Yawn rate increased in the buzzer-noise period relative to the first period of no punishment and first period of random punishment. These findings indicate that there are constraints that impede the suppression of yawning using punishment, and that yawning is a delayed response to fear produced by response-dependent punishment.

Effects of Struthanthus venetus methanol extract in the guinea pig heart.

Struthanthus venetus (Sv) from family Loranthaceae is employed in traditional medicine to treat coughs. In previous studies, a methanol extract of Sv shows hypotensive effects and changes in heart rate in rats. The purpose of this study was to determine the effect of a methanol extract of Sv on the electrocardiogram (EKG), and histological changes in the guinea pig heart. Male Hartley guinea pigs anesthetized with sodium pentobarbital received 50 mg/kg ip of Sv extract. An EKG was taken before and after the ip application of Sv extract. The EKG showed changes in QRS morphology, ST segment and T wave, Q wave in DI and AVL, data of ischemia, and myocardial injury. Guinea pigs were sacrificed after 1-93 days; the hearts were prepared for histopathological study with HE, PAS, Masson and Gallegos staining. The methanol extract of Sv causes apoptosis of myocardial fibers, degeneration of muscle fibers, staying only the fibro vascular skeleton, necrosis areas, hyperplasia of endothelial cells and mitotic figures in vascular endothelial cells and myocardial fibers. Changes in the EKG of the guinea pig could explain the hypotensive effects of Sv in rats. Sv extract causes cardio toxicity, apoptosis, autophagic and mitogenic activity in guinea pig heart, suggesting regeneration of the heart.