Sistema de bajo costo y alto rendimiento para bioensayos farmacológicos in vitro de tejido vivo / Low-Cost and High-Throughput System for Pharmacological Bioassays of Living Tissue in vitro

La potencialidad terapéutica de fármacos se averigua mediante estudios bioquímicos y celulares que nos hablan de sus acciones sobre vías de señalización y receptores. Sin embargo, en algunas enfermedades -por ejemplo, enfermedades neurológicas conocidas como "desórdenes del movimiento"-, los bioensayos realizados miden las acciones farmacológicas mediante valoraciones conductuales en modelos animales de las mismas. No se han logrado bioensayos que correlacionen la acción terapéutica de fármacos sobre la actividad del tejido vivo. Se puede medir la actividad de decenas de neuronas mediante imagenología de calcio en tejido vivo. Ciertos parámetros de esta actividad neuronal registrada in vitro reflejan su estado patológico, así como la acción terapéutica de fármacos determinados. No hay un sistema integrado orientado a estos bioensayos, por lo que se combinan diferentes equipos comerciales de manera independiente con costo final de alrededor de 100,000 USD. Presentamos un prototipo de un sistema integral encaminado a realizar este tipo de bioensayos: microscopía de epifluorescencia con calidad suficiente para adquirir y medir cuantitativamente la actividad celular del tejido vivo registrada in vitro pero de costo 10 veces menor -alrededor de 10,000 USD-. Se pueden realizar satisfactoriamente bioensayos funcionales de uso potencial en la industria farmacéutica, investigación y docencia.

The therapeutic potential of drugs is determined by biochemical and cellular studies that inform us about their actions on signaling pathways and receptors. However, in some diseases -for example, neurological diseases such as "movement disorders"-, bioassays measure the pharmacological actions by evaluating behavior in animal models of the diseases. There are no bioassays that correlate drug therapeutic actions on living tissue. The neural activity of several neurons can be measured by using calcium imaging on living tissue. Certain parameters of the recorded neuronal activity in vitro reflect the pathological state and the therapeutic actions of specific drugs. There is no integrated system oriented to these bioassays, so different commercial equipment has to be integrated independently with costs about 100,000 USD. We present a prototype of an integral system aimed to perform bioassays in vitro: epifluorescence microscopy with enough quality for the acquisition and quantitative assessment of cell activity recorded in the living tissue with costs around 10 times less -about 10,000 USD-. It allows successfully functional bioassays of potential use in the pharmaceutical industry, research an education.

Symmetry breaking in linearly coupled Korteweg-de Vries systems.

We consider solitons in a system of linearly coupled Korteweg-de Vries (KdV) equations, which model two-layer settings in various physical media. We demonstrate that traveling symmetric solitons with identical components are stable at velocities lower than a certain threshold value. Above the threshold, which is found exactly, the symmetric modes are unstable against spontaneous symmetry breaking, which gives rise to stable asymmetric solitons. The shape of the asymmetric solitons is found by means of a variational approximation and in the numerical form. Simulations of the evolution of an unstable symmetric soliton sometimes produce its breakup into two different asymmetric modes. Collisions between moving stable solitons, symmetric and asymmetric ones, are studied numerically, featuring noteworthy features. In particular, collisions between asymmetric solitons with identical polarities are always elastic, while in the case of opposite polarities the collision leads to a switch of the polarities of both solitons. Three-soliton collisions are studied too, featuring quite complex interaction scenarios.

Neurosífilis en pacientes portadores y no portadores de VIH: descripción y comparación de dos cohortes históricas / Neurosyphilis in the patients with and without HIV infection: description and comparison of two historical cohorts

Neurosyphilis follows a more aggressive and different clinical course in HIV-infected patients compared to patients with normal immunity. Two historical series of patients with a diagnosis of neurosyphilis between 1995 and 2008 were compared: they included a group of 15 patients with y and 28 patients without HIV infection. Probability of neurosyphilis in patients with positive serum VDRL was increased in patients infected with HIV comparedto HIV negative patients (OR: 62.37 IC:95 percent (32.1-119.1) p value:< 0,001). Predominant clinical manifestations in neurosyphilis in the HIV negative group were ocular abnormality, vascular encephalic and spinal cord lesions. In the HIV positive group, they were fever, ocular abnormalities and headache. There were no differences in cerebrospinal fluid characteristics between both groups. Neurosyphilis was diagnosed even in patients with blood VDRL of < 1:32, that happened in 17.8 percent of the HIV positive patients with blood and in 60 percent of t he HIV negative patients. Penicillin sodium given at dose ¡Ý than 18.000.000 IU/day IV during 14 days was the most common treatment. In patients with clinical neurosyphilis, 93 percent of HIV negative group, and 54.2 percent of HIV positive group had persistent neurological after-effects. Three HIV positive patients died due to causes not related to neurosyphilis.

[Hepatitis B, C, Treponema pallidum and Toxoplasma gondii co-infections in HIV infected patients]. / Coinfecciones por virus hepatitis B, virus hepatitis C, Treponema pallidum y Toxoplasma gondii en la cohorte de pacientes VIH positivos en control en la Pontificia Universidad Católica de Chile.

BACKGROUND: Some infections share common modes of transmission with HIV and have the potential to change the course of the latter. AIM: To assess the prevalence of hepatitis B virus (HBV) hepatitis C virus (HCV), Treponema palladium and Toxoplasmosis gondii co-infections in HIV-1 infected patients followed at a university hospital. MATERIAL AND METHODS: Clinical records of HIV-positive individuals were reviewed. The analysis included: demographical data, hepatitis B surface antigen (HBsAg), IgM and IgG anti-HBc, antibodies, anti-HCV antibodies, RPR or VDRL test and IgG anti Tgondii antibodies. RESULTS: Three hundred ninety five patients (aged 16 to 89 years, 359 males) were included in the review. Seventy nine percent had been tested for HBV status with HBsAg, and the global HIV-HBV co-infection prevalence was 6.1%. A subgroup of 190 individuals were tested for HBV infection with HBsAg and IgM/IgG anti-HBc markers. Of these, 46% fulfilled co-infection criteria: eight with acute hepatitis B, 11 with chronic hepatitis B and 69 with inactive HBV infection. The frequency of HIV-HBV co-infection was 48% and 22% among men and women respectively (NS). HCV-HN co-infection was detected in 3%, syphilis-HIV co-infection in 21% and T gondii-HIV co-infection in 26%. CONCLUSIONS: In this cohort, HIV infection is accompanied by a high prevalence of other co-infections, particularly HBV among men.

La enfermería en salud pública: el caso de la Influenza / The public health nursing: the case of influenza

Ante un brote de una enfermedad infecto-contagiosa, el estudio de contactos limita la transmisión de esta. El objetivo de este trabajo fue identificar a los contactos de los posibles casos de influenza en trabajadores de la UNAM para establecer una comunicación y proporcionar educación para la salud sobre medidas higiénicas. Material y métodos: Se elaboró un cuestionario, se estableció contacto con los casos por vía telefónica y se llevó a cabo una visita domiciliaria. Se llevó a cabo un análisis descriptivo de los datos y una descripción de las experiencias y percepciones durante las visitas. Resultados: Se identificó que la mayoría de los contactos eran familiares directos de los casos, que no contaban con un esquema de vacunación completo, ni contra la influenza y la frecuencia de síntomas varió de 1 hasta 4. Comentarios finales: Ante una situación de este tipo (la Pandemia del Virus de la Influenza Humana A (H1N1)) el papel de la enfermera en salud pública es de suma importancia no solo en la búsqueda de los casos y sus contactos, sino también en la orientación y educación de la población en relación a las medidas preventivas.

In the view of an infectious and contagious disease epidemic, the identification of the contacts limits its transmission. The objective of this work was to identify the contacts of the possible cases of UNAM workers in order to establish communication and provide health education about hygiene measures. Material and methods: A questionnaire was prepared, telephone contact was established with the cases, and a home visit was arranged. A descriptive analysis of the data was carried out, as well as, a description of the experiences and perception during the home visit. Results: Most identified contacts were relatives of the cases, which did not have a complete vaccine scheme, no even against influenza, and the frequency of symptoms varied between 1 a 4. Final comments: In a situation like this (A(H1N1) human influenza virus pandemic) the public health nurse roll is of great importance, not just in the identification of the cases and its contacts, but also in the orientation and education of the population in relation to preventive measures.

Coinfecciones por virus hepatitis B, virus hepatitis C, Treponema pallidum y Toxoplasma gondii en la cohorte de pacientes VIH positivos en control en la Pontificia Universidad Católica de Chile / Hepatitis B, C, Treponema pallidum and Toxoplasma gondii co-infections in HIV infected patients

Background: Some infections share common modes of transmission with HIV and have the potential to change the course of the latter. Aim: To assess the prevalence of hepatitis B virus (HBV) hepatitis C virus (HCV), Treponema palladium and Toxoplasmosis gondii co-infections in HIV-1 infected patients followed at a university hospital. Material and methods: Clinical records of HIV-positive individuals were reviewed. The analysis included: demographical data, hepatitis B surface antigen (HBsAg), IgM and IgG anti-HBc, antibodies, anti-HCV antibodies, RPR or VDRL test and IgG anti Tgondii antibodies. Results: Three hundred ninety five patients (aged 16 to 89years, 359 males) were included in the review. Seventy nine percent had been tested for HBV status with HBsAg, and the global HIV-HBV co-infection prevalence was 6.1 percent. A subgroup of190 individuals were tested for HBV infection with HBsAg and IgM/IgG anti-HBc markers. Of these, 46 percent fulfilled co-infection criteria: eight with acute hepatitis B, 11 with chronic hepatitis B and 69 with inactive HBV infection. The frequency of HIV-HBV co-infection was 48 percent and 22 percent among men and women respectively (NS). HCV-HN co-infection was detected in 3 percent, syphilis-HIV co-infection in 21 percent and T gondii-HIV co-infection in 26 percent. Conclusions: In this cohort, HIV infection is accompanied by a high prevalence of other co-infections, particularly HBV among men.

Standard and embedded solitons in nematic optical fibers.

A model for a non-Kerr cylindrical nematic fiber is presented. We use the multiple scales method to show the possibility of constructing different kinds of wave packets of transverse magnetic modes propagating through the fiber. This procedure allows us to generate different hierarchies of nonlinear partial differential equations which describe the propagation of optical pulses along the fiber. We go beyond the usual weakly nonlinear limit of a Kerr medium and derive a complex modified Korteweg-de Vries equation (CM KdV) which governs the dynamics for the amplitude of the wave packet. In this derivation the dispersion, self-focussing, and diffraction in the nematic fiber are taken into account. It is shown that this CM KdV equation has two-parameter families of bright and dark complex solitons. We show analytically that under certain conditions, the bright solitons are actually double-embedded solitons. We explain why these solitons do not radiate at all, even though their wave numbers are contained in the linear spectrum of the system. We study (numerically and analytically) the stability of these solitons. Our results show that these embedded solitons are stable solutions, which is an interesting property since in most systems the embedded solitons are weakly unstable solutions. Finally, we close the paper by making comments on the advantages as well as the limitations of our approach, and on further generalizations of the model and method presented.

Manifestaciones cutáneas del síndrome antifosfolípido / Cutaneous manifestations of the antiphospholipid syndrome

El Síndrome antifosfolípido es un transtorno caracterizado por trombosis arterial y venosa, pérdidas fetales recurrentes y, generalmente, trombocitopenia asocidada, en presencia de anticuerpos antifosfolípidos, tales como anticoagulante lúpico y anticuerpos anticardiolipinas. Dentro de la gran variedad de manifestaciones clínicas destaca la patología cutánea, que puede ser la primera expresión de la enfermedad. Las lesiones cutáneas incluyen: livedo reticularis vasculitis livedoide y necrotizante, tromboflebitis, necrosis y ulceración cutánea, máculas eritematosas, púrpura, equimosis, nódulos de la piel dolorosos y hemorragias en astilla subungueales, entre otras. Se presenta una revisión de los principales aspectos de la enfermedad (marcadores serológicos, patogenia, clasificación, clínica y tratamiento)

[Agrarian change and regional settling in Chile]. / Cambio agrario y poblamiento regional en Chile.

"This study analyzes the effect of agrarian change on regional settling dynamics in Chile during the last 35 years. The transformations of agrarian structure have produced important changes in the spatial configuration of country-city relations, particularly regarding the new features of rural-urban migration in regional contexts. Whereas until the sixties rural-urban migration was associated with an occupational shift from agriculture to urban employment, after the seventies this relation practically disappeared, leaving a virtual disassociation between the territorial mobility of the population and the occupational mobility of the labor force. This disassociation is a central trait of the current regional pattern of country-city relations." (SUMMARY IN ENG)