Vestibular dysfunction and its association with cognitive impairment and dementia.

The vestibular system plays an important role in maintaining balance and posture. It also contributes to vertical perception, body awareness and spatial navigation. In addition to its sensory function, the vestibular system has direct connections to key areas responsible for higher cognitive functions, such as the prefrontal cortex, insula and hippocampus. Several studies have reported that vestibular dysfunction, in particular bilateral vestibulopathy, is associated with an increased risk of cognitive impairment and the development of dementias such as Alzheimer's disease. However, it is still controversial whether there is a causal relationship between vestibular damage and cognitive dysfunction. In this mini-review, we will explore the relationship between the vestibular system, cognitive dysfunction and dementia, hypotheses about the hypothesis and causes that may explain this phenomenon and also some potential confounders that may also lead to cognitive impairment. We will also review multimodal neuroimaging approaches that have investigated structural and functional effects on the cortico-vestibular network and finally, describe some approaches to the management of patients with vestibular damage who have shown some cognitive impairment.

Across-species benefits of adrenalectomy on congenital generalized lipoatrophic diabetes: a review.

Two adrenalectomies py -45erformed fourteen years apart notoriously alleviated insulin resistance in a female teenager with Congenital Generalized Lipoatrophy (CGL, 1988) and in a murine model of CGL (2002). Following a successful therapeutic trial with anti-glucocorticoids, we performed the first surgical procedure on an 18-year-old girl. Before surgery, the anti-glucocorticoid therapy produced a rapid and striking drop in fasting serum insulin levels (from over 400 to 7.0 mU/L) and a slower -but impressive- fall in fasting serum triglycerides from 7,400 to 220-230 mg/dL. In contrast, fasting serum glucose levels dropped more slowly, from 225-290 to 121-138 mg/dL. Two weeks following total adrenalectomy, the fasting serum glucose level was 98 mg/dL, with a corresponding serum insulin level of 10 mU/L. During an Oral Glucose Tolerance Test, the 2-hour serum glucose was 210 mg/dL, and serum insulin values during the test did not exceed 53 mU/L. In 2002, the A-ZIP/F1 hypoleptinemic mouse had its adrenal glands removed. Even though this CGL model does not respond well to leptin replacement, an infusion of recombinant leptin reduced the characteristic hypercorticosteronemia of this murine model of CGL. Adrenalectomy in this transgenic mouse improved insulin sensitivity in the liver and muscle. In summary, adrenalectomy -in both a human and a mouse case of CGL- limited adipose tissue exposure to corticosteroid action and led to a notorious metabolic improvement. On a broader scenario, given that leptin restrains the adrenal axis, the reduced leptin activity of the leptin resistance displayed by obese subjects should lead to adrenal axis overactivity. This overactivity should result in elevated serum levels of free cortisol, free fatty acids, and glycerol. In this manner, leptin resistance should lead to peripheral (adipose tissue, liver, and muscle) insulin resistance and islet beta-cell apoptosis, paving the way to Type 2 diabetes.

Nickel Nanopillar Arrays Electrodeposited on Silicon Substrates Using Porous Alumina Templates.

Nickel nanopillar arrays were electrodeposited onto silicon substrates using porous alumina membranes as a template. The characterization of the samples was done by scanning electron microscopy, X-ray diffraction, and alternating force gradient magnetometry. Ni nanostructures were directly grown on Si by galvanostatic and potentiostatic electrodeposition techniques in three remarkable charge transfer configurations. Differences in the growth mechanisms of the nanopillars were observed, depending on the deposition method. A high correlation between the height of the nanopillars and the charge synthesis was observed irrespective of the electrochemical technique. The magnetization measurements demonstrated a main dependence with the height of the nanopillars. The synthesis of Ni nanosystems with a controllable aspect ratio provides an effective way to produce well-ordered networks for wide scientific applications.

Compliance of the 24-Hour Movement Guidelines in 9- to 11-Year-Old Children From a Low-Income Town in Chile.

BACKGROUND: The purpose was to determine the proportion of 9- to 11-year-old children meeting the 24-hour movement guidelines (24-HMG) in a low-income town from Chile. METHODS: Physical activity, sedentary behavior (recreational screen), and sleep times were measured with both questionnaire and accelerometer in 258 children from third to sixth grade. Meeting the 24-HMG was defined as having ≥60 minutes per day of moderate to vigorous physical activity, ≤2 hour day of screen time, and 9 to 11 hours of sleep per night. Compliance rates were calculated as self-reported 24-HMG, with all estimations based on questionnaires, and mixed 24-HMG, in which physical activity and sleep were determined with an accelerometer and sedentary behavior was determined with a questionnaire. RESULTS: About 198 children (10.1 [0.8] y, range 9-11 y) provided valid data for estimating self-reported 24-HMG, and 141 for mixed 24-HMG. Only 3.2% and 0.7% met the 24-HMG when using the self-reported and mixed methods, respectively. When assessing individual recommendations, 13.1% and 3.7% of the sample were physically active based on the self-report and accelerometer, respectively. About a quarter met the sedentary behavior recommendations, while around 50% met the sleep recommendations with both self-reported and mixed methods. CONCLUSIONS: An extremely low percentage of the participants met the 24-HMG. Multicomponent initiatives must be implemented to promote healthy movement behaviors in Chilean children.

Usando la curva de tolerancia a la glucosa para calcular el porcentaje relativo de sensibilidad insulínica y el porcentaje relativo de función beta insular / A program to estimate insulin resistance based on data from the oral glucose tolerance test

Background An instrument to help clinicians to evaluate the oral glucose tolerance test (OGTT) at-a-glance is lacking. Aim To generate a program written in HTML squeezing relevant information from the OGTT with glucose and insulin measurements. Material and Methods We reanalyzed a database comprising 90 subjects. All of them had both an OGTT and a pancreatic suppression test (PST) measuring insulin resistance directly. Thirty-seven of the 90 studied participants were insulin resistant (IR). Receiver operating characteristic (ROC) curves and Bayesian analyses delineated the diagnostic performances of four predictors of insulin resistance: HOMA, QUICKI, ISI-OL (Matsuda-DeFronzo) and I0*G60. We validated a new biochemical predictor, the Percentual Relative Insulin Sensitivity (%RIS), and calculated the Percentual Relative Beta Cell Function (%RBCF). Results The best diagnostic performance of the five predictors were those of the I0*G60 and the %RIS. The poorest diagnostic performances were those of the HOMA and QUICKI. The ISI-OL's performance was in between. The %RIS of participants with and without IR was 44.4 ± 7.3 and 101.1 ± 8.8, respectively (p < 0.05). The figures for % RBCF were 55.8 ± 11.8 and 90.8 ± 11.6, respectively (p < 0.05). Mathematical modeling of the relationship between these predictors and the Steady State Plasma Glucose Value from the PST was performed. We developed a program with 10 inputs (glucose and insulin values) and several outputs: I0*G60, HOMA, QUICKI, ISI-OL, Insulinogenic Index, Disposition Index, %RBCF, %RIS, and metabolic categorization of the OGTT (ADA 2003). Conclusions The OGTT data permitted us to write successfully an HTML program allowing the user to fully evaluate at-a-glance its metabolic information.

A Simple and Improved Predictor of Insulin Resistance Extracted From the Oral Glucose Tolerance Test: The I0*G60.

OBJECTIVE: To evaluate the diagnostic performance of several biochemical predictors of insulin resistance (IR). DESIGN: A total of 90 nondiabetic subjects were tested with both the pancreatic suppression test (PST) and the oral glucose tolerance test (OGTT). Of them, 53 were non-insulin-resistant (NIR) subjects and the remaining 37 were insulin resistant subjects. RESULTS: All glucose and insulin values from the OGTT were positively correlated with the steady-state plasma glucose (SSPG) value of the PST. Among the OGTT values, basal insulin (I0) displayed a stronger correlation with SSPG (r = 0.604). Receiver operating characteristic analysis of the OGTT data demonstrated that I0 exhibited the highest area under the receiver operating characteristic curve (AUROC), compared with the rest of the OGTT data. However, the reduced sensitivity of this predictor precluded its clinical use.We then tested six potential predictors of IR derived from the OGTT values. Of them, the I0*G60 had a correlation coefficient of 0.697 with the SSPG and an AUROC of 0.867, surpassing the respective values of the traditional biochemical predictors of IR. Its cutoff predicting IR was >1110 mg/dL*µΙU/mL (>428 nM*pM), its sensitivity was 0.865, and its global accuracy was 0.822. We then selected the six best biochemical predictors of IR according to their posttest probability ratio. The order was as follows: I0*G60, ISI composite, AUC-Gl*In/', quantitative insulin sensitivity check index, homeostatic model assessment 1 (HOMA1), and HOMA2. CONCLUSION: We conclude that the I0*G60 is a promising, inexpensive, and easily calculable predictor of IR that outperforms the predictive power of the traditional predictors of IR, including the insulin sensitivity index composite.

Insulin Sensitivity and Testicular Function in a Cohort of Adult Males Suspected of Being Insulin-Resistant.

A cohort of 141 males (18-80 yo, 42.9 ± 12.9) strongly suspected of being Insulin Resistant (IR) was prospectively studied by determining their insulin sensitivity (Pancreatic Suppression Test, PST) and testicular function (total testosterone and SHBG). The subjects were labeled as IR when the Steady State Plasma Glucose (SSPG) was ≥150 mg/dL and Non-Insulin Resistant (NIR) when SSPG was <150 mg/dl; similarly, the subjects were labeled as Hypogonadal (HYPOG) when total testosterone was ≤3.0 ng/mL and Eugonadal (EUG) when total testosterone was >3.0 ng/mL. Two out of three subjects turned out to be IR, while around one in four subjects were HYPOG. Contingency analysis indicated a significant interdependence between insulin resistance and hypogonadism (chi-square was 4.69, p = 0.0303). Age (>43 yo) predicted hypogonadism (AUROC 0.606, p = 0.0308). Twice as many HYPOG subjects were IR as compared with EUG subjects. Also, HYPOG subjects exhibited higher SSPG values as compared with EUG subjects. Statistically, neither Weight nor BMI predicted hypogonadism, while Waist Circumference (>110 cm) was only a mediocre predictor (AUROC 0.640, p = 0.009). SSPG (>224 mg/dL) on the other hand, was the best predictor of hypogonadism (AUROC 0.709, p = 0.002), outperforming Waist Circumference (half of the subjects with an SSPG >224 mg/dL were HYPOG). Age did not predict insulin resistance, while Weight (>99 kg), BMI (>29), and especially, Waist Circumference (>99 cm, AUROC 0.812, p < 0.0001) were all predictors of insulin resistance. Almost 90% of the subjects with a waist circumference >99 cm was IR. As a logical consequence of the selection criteria (various clues suggesting insulin resistance), most subjects with normal weight in this cohort were IR (53.3%) while 20% were HYPOG. On the other hand, 13.6% of the obese subjects were NIR, and 2 out of 3 of them were both NIR and EUG. In conclusion, Waist Circumference predicted both insulin resistance (>99 cm) and hypogonadism (>110 cm), suggesting that the first hit of abdominal obesity is insulin resistance and the second hit is male hypogonadism. Normal weight did not protect from IR, while a relevant proportion of obese subjects were NIR (with 2/3 being also EUG).

Evaluación del desarrollo e impacto de un curso de habilidades de comunicación efectiva en estudiantes de Tecnología Médica de la Universidad de Chile / Assessment of the development and impact of the course "Profession, person and Society" in the Medical Technologist's students of the University of Chile

Introducción : En la carrera de Tecnología Médica de la Universidad de Chile, en el año 2014 se diseñó el curso de "Profesión, Persona y Sociedad" que se dicta en el cuarto semestre, el cual pretende que los estudiantes apliquen habilidades de comunicación verbal y no verbal, entendiendo la comunicación como una herramienta esencial para la interacción en el ámbito de las ciencias de la salud. Al finalizar la cuarta versión de este curso, es necesario indagar en el impacto que éste ha tenido en los estudiantes a través de las opiniones que han expresado en instancias de retroalimentación disponibles.Objetivos : Evaluar el impacto del curso en los estudiantes y su evolución en sus cuatro versiones (2014 - 2017) a través de variables cuantitativas en las dimensiones pedagógica, dominio disciplinar, relaciones interpersonales y responsabilidades administrativas. Además se realizó análisis cualitativo de las respuestas a preguntas abiertas con las impresiones de los estudiantes. Método : Para el período comprendido entre los años 2014 y 2016 se analizaron cuantitativa y cualitativamente las encuestas de evaluación docente del curso, se calculó la diferencia porcentual para cada variable. Para el año 2017 se evaluó, además, la reflexión personal que los estudiantes realizan del curso al finalizar el semestre a través de la técnica de análisis de discurso. Resultados : Se observa una valoración progresiva de la importancia del curso en la formación de los estudiantes conforme avanzan las versiones, logrando un impacto positivo en cada una de las generaciones. En los puntajes de todas las áreas evaluadas se observaron mejoras en las versiones, lo cual se condice con las opiniones expresadas en las respuestas abiertas. Conlusiones : El curso cumple su función de que los estudiantes valoren la importancia de la comunicación efectiva en salud como herramienta profesional. Además valoran el rol que tiene en evidenciar falencias propias y motivarlos a trabajarlas. El curso muestra mejoras concretas en su aplicación conforme avanzan sus versiones, sin embargo hay áreas en las cuales se debe seguir trabajando, lo cual es un desafío a un proceso de mejora continua(AU)

Introduction : In the Medical Techologist's University of Chile undergraduate program, in 2014 was designed the "profesión, persona y sociedad" course, that is offered in the fourth semester. This course pretends that the students apply skills relationated with verbal and non-verbal communication in the context of the work in medical scenarios. At the end of the fourth version is neccesary to know the impact that the course have had in the students for the analysis of the opinions that they have done in many retroalimentation's moments. Aim: To assess the impact of the course in the students and it's evolution through the four versions (from 2014 until 2017) with cuantitative variables in the dimensions: teaching, knowledge, interpersonal relations and administrative responsabilities. Methods : For the period between 2014 and 2016, the evaluation surveys of the course were quantitatively and qualitatively oriented, the percentage difference for each variable was calculated. For the year 2017, in addition to the teacher evaluation survey, the personal reflection that the students made the course at the end of the semester through the discourse analysis technique was evaluated. Results : A progressive assessment of the importance of the course in the formation of the students is observed as the versions advance, achieving a positive objective impact in each of the generations. In the scores of all the areas evaluated improvements were observed as the versions advanced, which is consistent with the opinions expressed in the open answers. Conclusions : The course fulfills its function that students value the importance of the development of effective communication in health as a professional tool more. On the other hand, they value their role in showing their own shortcomings and motivate them to work on them. The course shows concrete improvements in its application as its versions advance, however there are areas in which work must be continued, which is a challenge to a process of continuous improvement(AU)

Disposición de los usuarios a participar en las prácticas clínicas de la carrera de Tecnología Médica de la Universidad de Chile / The users' willingness to participate in the clinical internships of the major Medical Technology of the University of Chile i:en

Introducción: los usuarios están empoderados de sus problemas de salud y derechos, esto obliga a los hospitales docentes a compatibilizar sus funciones asistencial y docente. Los usuarios a menudo juegan un rol pasivo en las prácticas, pero el cambio curricular hacia los modelos por competencias puede ser una oportunidad para involucrar a los usuarios en su evaluación. Objetivos: conocer la disposición de los usuarios a participar en prácticas clínicas y su rol en el proceso de enseñanza-aprendizaje. Métodos: se realizó una entrevista semiestructurada a ocho usuarios del Centro de Imagenología del Hospital Clínico de la Universidad de Chile que contenía cinco preguntas abiertas que se analizaron de manera cualtativa. Las dimensiones analizadas abordaban la opinión respecto a ser sujetos de aprendizaje y la percepción de su rol actual en el desarrollo de prácticas. Resultados: los usuarios entrevistados tienen buena disposición a participar de las prácticas clínicas, pero expresan el deseo de ser informados de manera explícita antes de ser parte de ellas. A su vez, sienten que su rol es ser un facilitador físico para el logro de competencias en los estudiantes. Si pudieran evaluar a un estudiante luego de la atención, sienten que su colaboración sería para fortalecer habilidades comunicacionales de los estudiantes. Conclusiones: la disposición de los usuarios constatada en este estudio puede ser usada como un recurso para introducir la opinión del usuario en la evaluación de prácticas clínicas, de los estudiantes de Tecnología Médica de la Universidad de Chile. Es necesario implantar la solicitud de consentimiento informado explícito de actividades docentes para afianzar la disposición evidenciada(AU)

Introduction: The users are empowered regarding their rights and health issues, which compels the teaching hospitals to make their health care and teaching functions compatible. The users sometimes play a passive role in the internships, but the curricular change towards the competence models may be an opportunity to engage the users in their assessment. Objective: Know the users' willingness to participate in the clinical internships and their role in the teaching-learning process. Methods: A semi-structured interview with eight open questions qualitatively analyzed was conducted on eight users of the Image Center of the Clinical Hospital at the University of Chile. The analyzed dimensions considered their opinions about being subjects of the learning process and their perception about their current role in the development of internships. Results: The users interviewed have a goodwill to participate in the clinical internships, but express their wish to be explicitly informed before being part of them. They also feel that their role is being a physical facilitator for the students' competences. They feel that, if they could evaluate a student's after being treated, their cooperation would strengthen the students' communication skills. Conclusions: The users' willingness verified in this study may be used as a resource to introduce the user's opinion into the evaluation of clinical internships of the Medical Technology students of University of Chile. The explicit and informed consent request for teaching activities need to be implemented to consolidate the willingness shown(AU)

Disposición de los usuarios a participar en las prácticas clínicas de la carrera de Tecnología Médica de la Universidad de Chile / The users' willingness to participate in the clinical internships of the major Medical Technology of the University of Chile

Introducción: los usuarios están empoderados de sus problemas de salud y derechos, esto obliga a los hospitales docentes a compatibilizar sus funciones asistencial y docente. Los usuarios a menudo juegan un rol pasivo en las prácticas, pero el cambio curricular hacia los modelos por competencias puede ser una oportunidad para involucrar a los usuarios en su evaluación. Objetivos: conocer la disposición de los usuarios a participar en prácticas clínicas y su rol en el proceso de enseñanza-aprendizaje. Métodos: se realizó una entrevista semiestructurada a ocho usuarios del Centro de Imagenología del Hospital Clínico de la Universidad de Chile que contenía cinco preguntas abiertas que se analizaron de manera cualtativa. Las dimensiones analizadas abordaban la opinión respecto a ser sujetos de aprendizaje y la percepción de su rol actual en el desarrollo de prácticas. Resultados: los usuarios entrevistados tienen buena disposición a participar de las prácticas clínicas, pero expresan el deseo de ser informados de manera explícita antes de ser parte de ellas. A su vez, sienten que su rol es ser un facilitador físico para el logro de competencias en los estudiantes. Si pudieran evaluar a un estudiante luego de la atención, sienten que su colaboración sería para fortalecer habilidades comunicacionales de los estudiantes. Conclusiones: la disposición de los usuarios constatada en este estudio puede ser usada como un recurso para introducir la opinión del usuario en la evaluación de prácticas clínicas, de los estudiantes de Tecnología Médica de la Universidad de Chile. Es necesario implantar la solicitud de consentimiento informado explícito de actividades docentes para afianzar la disposición evidenciada(AU)

Introduction: The users are empowered regarding their rights and health issues, which compels the teaching hospitals to make their health care and teaching functions compatible. The users sometimes play a passive role in the internships, but the curricular change towards the competence models may be an opportunity to engage the users in their assessment. Objective: Know the users' willingness to participate in the clinical internships and their role in the teaching-learning process. Methods: A semi-structured interview with eight open questions qualitatively analyzed was conducted on eight users of the Image Center of the Clinical Hospital at the University of Chile. The analyzed dimensions considered their opinions about being subjects of the learning process and their perception about their current role in the development of internships. Results: The users interviewed have a goodwill to participate in the clinical internships, but express their wish to be explicitly informed before being part of them. They also feel that their role is being a physical facilitator for the students' competences. They feel that, if they could evaluate a student's after being treated, their cooperation would strengthen the students' communication skills. Conclusions: The users' willingness verified in this study may be used as a resource to introduce the user's opinion into the evaluation of clinical internships of the Medical Technology students of University of Chile. The explicit and informed consent request for teaching activities need to be implemented to consolidate the willingness shown(AU)

Evidence of subpopulations with different levels of insulin resistance in women with polycystic ovary syndrome.

BACKGROUND: Polycystic ovary syndrome (PCOS) is non-uniformly associated with insulin resistance (IR). We examined IR in women with PCOS. METHODS: Sixty-nine PCOS women were subjected to the insulin suppression test (IST) to determine their steady-state plasma glucose (SSPG) as a direct measure of insulin sensitivity. RESULTS: SSPG exhibited a multimodal distribution suggesting the existence of subpopulations. The heterogeneous distribution of plasma glucose at 180 min (P = 0.011), with three modes, suggested differences in the plasma glucose level trajectories during the IST. Hence, the population was separated into three groups: (i) (n = 33), subjects with SSPG < or = 152.5 mg/dl, corresponding to the first to fifth deciles; (ii) (n = 29), subjects in the interval 152.5 mg/dl < SSPG < or = 300 mg/dl; (iii) (n = 7), subjects with SSPG > 300 mg/dl, corresponding to the tenth decile. Plasma glucose distributions at 180 min showed differences in their mean values and ranges among groups (P < 0.0001). The trajectories of the groups differed significantly during the IST (P < 0.0001). CONCLUSIONS: insulin sensitivity in our patients exhibited a discontinuous distribution, implying that PCOS is a heterogeneous disorder possessing subpopulations regarding IR.

El uso del factor liberador de hormona de crecimiento (GRF) como prueba de reserva hipofisiaria para hormona de crecimiento (hGH) / Growth hormone releasing factor (GRF) as a test of pituitary reserve of growth hormone (hGH)

Diferentes pruebas inespecíficas de estimulación se emplean para estudiar la capacidad de la hipófisis para secretar hormona del crecimiento, pero ninguno es totalmente confiable. Los autores emplearon factor liberador de hormona del crecimiento (1microng x kg de peso corporal endovenoso) en 6 niños de talla baja pero sin afecciones endocrinas y en 4 pacientes con deficiencia comprobada de hormona del crecimiento. La concentración plasmática máxima de la hormona en los niños normales, durante la prueba, fue de 47,4 + ou - 15,4 ng x ml. Tres de los cuatro pacientes no mostraron respuesta a la provocación y en el cuatro la concentración plasmática máxima alcanzada fue de 5,3 ng x ml sugiriendo un origen hipotalámico para su deficiencia hormonal. El empleo de factor liberador sería de utilidad en el futuro para el diagnóstico y tratamiento de la deficiencia de hormona del crecimiento