Tubular vs. mini-open lumbar discoidectomy: surgical-clinical outcome.

OBJECTIVE: To evaluate the clinical-surgical results of the tubular vs. mini-open approach in lumbar discoidectomy. The tubular approach promises to reduce the number of rest days and an earlier return to daily activities and work. METHOD: A case-control study of patients operated on for disc herniation using tubular surgery (case) and mini-open (control) was carried out. The variables investigated were as follow: radicular and lumbar pain, sex, age, failure in conservative treatment, single-level lumbar hernia, surgical time, bleeding, length of hospital stay, persistence of symptoms, complications, occupational activity, and reintegration into everyday activities. RESULTS: Through 100 surgeries performed, two groups were created, tubular and mini-open, with 50 patients each, with L4-L5 or L5-S1 disc herniation, respectively. The most affected level was L4-L5 (69%). Of the total cases, a significant improvement was found (p < 0.05) at 15 postoperative days in the VAS and ODI scale in the tubular group with respect to mini-open. Complications such as surgical wound infection, durotomy, and persistent pain occurred. CONCLUSIONS: The tubular approach is a safe and effective option for herniated discs of the lumbar segment, and reduces surgical times, bleeding, and the time of reinsertion to daily activities of the patient.

OBJETIVO: Evaluar los resultados clínico-quirúrgicos del abordaje tipo tubular en comparación con el mini-open en la discoidectomía lumbar. El abordaje tubular promete reducir el número de días de reposo y una reincorporación más temprana a las actividades diarias y laborales. MÉTODO: Se realizó un estudio de casos y controles de pacientes operados por hernia discal mediante cirugía tubular (casos) o mini-open (controles). Las variables investigadas fueron: dolor radicular y lumbar, sexo, edad, falla en el tratamiento conservador, hernia lumbar de un solo nivel, tiempo quirúrgico, sangrado, tiempo de estancia hospitalaria, persistencia de síntomas, complicaciones, tipo de actividad ocupacional y reinserción a las actividades cotidianas. RESULTADOS: Se realizaron 100 cirugías y se crearon dos grupos, tubular y mini-open, con 50 pacientes cada uno, con hernia discal de L4-L5 o L5-S1, respectivamente. El nivel más afectado fue L4-L5 (69%). Del total de los casos, se encontró mejoría significativa (p < 0.05) a los 15 días posquirúrgicos en la escala EVA y ODI en el grupo tubular con respecto al mini-open. Ocurrieron complicaciones como infección de herida quirúrgica, durotomía y dolor persistente. CONCLUSIONES: El abordaje tubular es una opción segura y efectiva para hernias discales del segmento lumbar, y reduce los tiempos quirúrgicos, el sangrado y el tiempo de reinserción a las actividades cotidianas del paciente.

Two-photon absorption spectrometers for near infrared.

We present a Silicon-based Charge-Coupled Device (Si-CCD) sensor applied as a cost-effective spectrometer for femtosecond pulse characterization in the Near Infrared region in two different configurations: two-Fourier and Czerny-Turner setups. To test the spectrometer's performance, a femtosecond Optical Parametric Oscillator with a tuning range between 1100 and 1700 nm and a femtosecond Erbium-Doped Fiber Amplifier at 1582 nm were employed. The nonlinear spectrometer operation is based on the Two-Photon Absorption effect generated in the Si-CCD sensor. The achieved spectrometer resolution was 0.6 ± 0.1 nm with a threshold peak intensity of 2×106Wcm2. An analysis of the nonlinear response as a function of the wavelength, the response saturation, and the criteria to prevent it are also presented.

Assisted dorso-lumbar instrumentation with O-arm neuronavegation and minimally invasive surgery: clinical-surgical outcome.

OBJECTIVE: To evaluate the clinical-surgical outcomes after dorso-lumbar instrumentation using O-arm assisted neuronavigation and minimally invasive surgery. METHOD: In this retrospective cohort, 104 patients who underwent dorso-lumbar instrumentation with the use of O-arm from September 2013 to May 2020 were studied. Variables investigated included: symptoms, number of screws, levels approached, bleeding, surgical time, hospital stay, complications and clinical improvement after the surgical procedure. RESULTS: The most frequent symptoms were: unilateral or bilateral radiculopathy of the pelvic extremities, paresthesia, mechanical low back pain and progressive decrease in strength. A total of 542 screws were placed, with the lumbar spine being the site with the highest prevalence. The average bleeding, surgical time, and hospital stay was: 50 ml, 160 minutes, and 24 hours, respectively. The most frequent complications were: Residual neuropathy, dura mater tear and surgical site infection. Clinical improvement at 24 hours, 4 weeks and 6 months was achieved in: 77.3%, 86.5% y 94.8% of the patients, respectively. CONCLUSIONS: Neuronavigation with the use of O-arm along with mini-open surgery approach results in good clinical-surgical outcomes in the correction of complex disorders of the dorso-lumbar spine.

OBJETIVO: Evaluar los resultados clínico-quirúrgicos de la instrumentación dorso-lumbar mediante neuronavegación asistida con O-arm y cirugía mínimamente invasiva. MÉTODO: En esta cohorte retrospectiva se estudiaron 104 pacientes sometidos a instrumentación dorso-lumbar con uso de O-arm, operados entre septiembre de 2013 y mayo de 2020. Las variables investigadas fueron sintomatología, cantidad de tornillos, niveles abordados, sangrado, tiempo quirúrgico, estancia hospitalaria, complicaciones y mejoría clínica posterior al procedimiento quirúrgico. RESULTADOS: La sintomatología más frecuente fue radiculopatía unilateral o bilateral de extremidades pélvicas, parestesias, lumbalgia mecánica y disminución progresiva de la fuerza. Se utilizaron en total 542 tornillos, siendo la columna lumbar el sitio de mayor prevalencia. Los promedios de sangrado, tiempo quirúrgico y estancia hospitalaria fueron de 50 ml, 160 minutos y 24 horas, respectivamente. Las complicaciones más frecuentes fueron neuropatía residual, rasgadura de la duramadre e infección del sitio quirúrgico. La mejoría clínica a las 24 horas, 4 semanas y 6 meses se logró en el 77.3%, el 86.5% y el 94.8% de los pacientes, respectivamente. CONCLUSIONES: La neuronavegación con O-arm junto con el abordaje quirúrgico de tipo mini-open permite buenos resultados clínico-quirúrgicos en la corrección de los trastornos complejos de la columna dorso-lumbar.

Interference effects in quantum-optical coherence tomography using spectrally engineered photon pairs.

Optical-coherence tomography (OCT) is a technique that employs light in order to measure the internal structure of semitransparent, e.g. biological, samples. It is based on the interference pattern of low-coherence light. Quantum-OCT (QOCT), instead, employs the correlation properties of entangled photon pairs, for example, generated by the process of spontaneous parametric downconversion (SPDC). The usual QOCT scheme uses photon pairs characterised by a joint-spectral amplitude with strict spectral anti-correlations. It has been shown that, in contrast with its classical counterpart, QOCT provides resolution enhancement and dispersion cancellation. In this paper, we revisit the theory of QOCT and extend the theoretical model so as to include photon pairs with arbitrary spectral correlations. We present experimental results that complement the theory and explain the physical underpinnings appearing in the interference pattern. In our experiment, we utilize a pump for the SPDC process ranging from continuous wave to pulsed in the femtosecond regime, and show that cross-correlation interference effects appearing for each pair of layers may be directly suppressed for a sufficiently large pump bandwidth. Our results provide insights and strategies that could guide practical implementations of QOCT.

Low-energy/pulse response and high-resolution-CMOS camera for spatiotemporal femtosecond laser pulses characterization @ 1.55 µm.

In this work, we present a commercial CMOS (Complementary Metal Oxide Semiconductor) Raspberry Pi camera implemented as a Near-Infrared detector for both spatial and temporal characterization of femtosecond pulses delivered from a femtosecond Erbium Doped Fiber laser (fs-EDFL) @ 1.55 µm, based on the Two Photon Absorption (TPA) process. The capacity of the device was assessed by measuring the spatial beam profile of the fs-EDFL and comparing the experimental results with the theoretical Fresnel diffraction pattern. We also demonstrate the potential of the CMOS Raspberry Pi camera as a wavefront sensor through its a nonlinear response in a Shack-Hartmann array and for the temporal characterization of the femtosecond pulses delivered from the fs-EDFL through TPA Intensity autocorrelation measurements. The direct pulse detection and measurement, through the nonlinear response with a CMOS, is proposed as a novel and affordable high-resolution and high-sensitivity alternative to costly detectors such as CCDs, wavefront sensors and beam profilers @ 1.55 µm. The measured fluence threshold, down to 17.5 µJ/cm2, and pJ/pulse energy response represents the lowest reported values applied as a beam profiler and a TPA Shack-Hartmann wavefront sensor, to our knowledge.

Webcam autofocus mechanism used as a delay line for the characterization of femtosecond pulses.

In this work, we present an electromagnetic focusing mechanism (EFM), from a commercial webcam, implemented as a delay line of a femtosecond laser pulse characterization system. The characterization system consists on a second order autocorrelator based on a two-photon-absorption detection. The results presented here were performed for two different home-made femtosecond oscillators: Ti:sapph @ 820 nm and highly chirped pulses generated with an Erbium Doped Fiber @ 1550 nm. The EFM applied as a delay line represents an excellent alternative due its performance in terms of stability, resolution, and long scan range up to 3 ps. Due its low power consumption, the device can be connected through the Universal Serial Bus (USB) port. Details of components, schematics of electronic controls, and detection systems are presented.

Análisis de la vulnerabilidad biofísica a los riesgos por inundación en la zona metropolitana de Toluca, México / Biophysics vulnerability analysis to flooding risk in the metropolitan area of toluca, Mexico

Se realizó el análisis multicriterio de los factores físico-naturales de la Zona Metropolitana de Toluca (ZMT), con la finalidad de definir el índice biofísico de exposición a los riesgos por inundación. Para la elaboración del trabajo se utilizó información institucional e información de campo, la cual fue procesada a través de los métodos estadísticos y multicriterio con el apoyo de los Sistemas de Información Geográfica y de percepción remota. Los resultados obtenidos mostraron que el índice de riesgo alto, con un valor de 52,41% comprende los municipios de Lerma, Toluca, San Mateo Atenco y Metepec y cubre una superficie de 1032,73 km²; el índice bajo cubre el 13,71% del territorio y una superficie 13,71 km²; por último el riesgo biofísico medio abarca 687,20 km² o 33,88% del territorio metropolitano. Se pretende que los resultados de la investigación contribuyan en la toma de decisiones en los campos de la protección civil, el desarrollo regional y la seguridad pública, así como la incorporación en los planes de desarrollo urbano y ordenamiento territorial con una visión de riesgo; y sea de utilidad en los campos de la protección civil, el desarrollo metropolitano, la seguridad pública y el ordenamiento territorial.

A multicriteria analysis of natural physical factors of the Toluca Metropolitan Area (ZMT) was performed in order to define the biophysical index of exposure to flood risk. Institutional information and field information was used for carrying out the work and it was processed through statistical and multi-criteria methods with the support of GIS and remote sensing. The results showed that the rate of high risk, with a 52.41% value includes the municipalities of Lerma, Toluca, San Mateo Atenco and Metepec, and covers an area of 1032.73 km². The low rate covers 13.71 % of the territory and an area of 13.71 km², and finally the average biophysical risk covers 687.20 km² or 33.88% of the metropolitan area. It is intended that the research results contribute to decision making in the fields of civil protection, regional development and public safety, as well as incorporation into urban development plans and land use planning with a view of risk, and be useful in the fields of civil protection, metropolitan development, public safety and land use planning.

Direct inversion methods for spectral amplitude modulation of femtosecond pulses.

In the present work, we applied an amplitude-spatial light modulator to shape the spectral amplitude of femtosecond pulses in a single step, without an iterative algorithm, by using an inversion method defined as the generalized retardance function. Additionally, we also present a single step method to shape the intensity profile defined as the influence matrix. Numerical and experimental results are presented for both methods.

A metal mixture induces transformation upon antioxidant depletion in a hepatic cell line.

INTRODUCTION: Metals are ubiquitous soil, air, and water pollutants. A mixture of arsenic cadmium and lead, in particular, has commonly been found in the vicinity of smelter areas. The mixture of As-Cd-Pb has been shown to be carcinogenic, and transforming potential and oxidative stress have been proposed as principal mechanisms involved in this process. The aim of this work was to explore the role of the antioxidant barrier in the establishment of cell transformation upon chronic exposure to a metal mixture containing 2 µM NaAsO(2), 2 µM. CdCl(2), and 5 µM Pb(C(2)H(3)O(2))(2)∙3H(2)O in WRL-68 cells-a non-transformed human hepatic cell line. MATERIAL AND METHODS: In this study, we used a WRL-68 cell model of human embryonic hepatic origin treated with antioxidant inhibitors (L-Buthionine-sulfoxamine and aminotriazole) to test the role of the antioxidant barrier in the establishment of cell transformation upon chronic exposure to a metal mixture of As-Cd-Pb (2 µM NaAsO(2), 2 µM CdCl(2) and 5 µM Pb(C(2)H(3)O(2))(2)∙3H(2)O). We evaluated oxidative damage markers, including reactive oxygen species, lipid peroxidation, and genotoxicity, as well as antioxidant response markers, including glutathione concentration, catalase activity, and superoxide dismutase activity, which promote morphological transformation, which can be quantified by foci formation. RESULTS: As expected, we found an increase in the intracellular concentration of the metals after treatment with the metal mixture. In addition, treatment with the metal mixture in addition to inhibitors resulted in a large increase in the intracellular concentration of cadmium and lead. Our results describe the generation of reactive oxygen species, cytotoxicity, genotoxicity, and oxidative damage to macromolecules that occurred exclusively in cells that were morphologically transformed upon exposure to a metal mixture and antioxidant barrier inhibition. CONCLUSION: Our results show the importance of the antioxidant barrier role in the protection of cellular integrity and the transformation potential of this metal mixture via free radicals.

DNA damage in blood cells from children exposed to arsenic and lead in a mining area.

In this work, we studied the frequency of DNA damage in children living in Villa de la Paz, Mexico, a mining site contaminated with arsenic and lead. DNA damage in blood cells was assessed using the Comet assay, and the results were compared to those found in children living in a less exposed town (Matehuala). In Villa de la Paz, high concentrations of arsenic and lead in surface soil and household dust were found. All of the soil samples had concentrations above 100 mg/kg of arsenic, and 58% of the samples were higher than 400 mg/kg of lead (these concentrations are used as intervention guidelines by the United States Environmental Protection Agency). In agreement with the environmental results, urinary arsenic in children living in Villa de la Paz (geometric mean 136 microg/g creatinine) was significantly higher than that found in children living in Matehuala (34 microg/g creatinine). Blood lead levels were also significantly higher in children from Villa de la Paz (11.6 microg/dL) than in children from Matehuala (8.3 microg/dL). The results of the Comet assay showed that the tail length and the tail moment in children living in Villa de la Paz were higher than those observed for children in Matehuala (P<0.05). Taking all the data into account, our study has shown increased DNA damage in children exposed to arsenic and lead in the mining site of Villa de la Paz.

Genotoxicity induced in CD-1 mice by inhaled lead: differential organ response.

Lead is perhaps the longest used and best recognized toxic environmental chemical and it is still being used recklessly. Lead (Pb) has been found to be capable of eliciting a positive response in an extraordinarily wide range of biological and biochemical tests; among them tests for enzyme inhibition, fidelity of DNA synthesis, mutation, chromosomal aberrations, cancer and birth defects. Since inhalation is one of the most important routes of environmental Pb exposure, in the present study a lead inhalation model in mice was implemented in order to detect the induction of genotoxic damage as single-strand breaks and alkali-labile sites in several mouse organs (nasal epithelial cells, lung, whole blood, liver, kidney, bone marrow, brain and testes), assessed by single cell gel electrophoresis (SCGE) or Comet assay. We found differences among the organs studied after a single and subsequent inhalations: in the organs analyzed we observed a positive induction of DNA damage after a single inhalation only in the liver and the lung. In subsequent inhalations the response was positive in all organs except the testicle, however, DNA damage induction over time was different for each organ. A correlation between length of exposure, DNA damage and metal tissue concentration was observed for lung, liver and kidney. Differences in DNA damage occurred in organs when lead acetate was administered acutely or sub-chronically. These results show that lead acetate inhalation induces systemic DNA damage but that some organs are special targets of this metal, such as lung and liver, depending in part on length of exposure, suggesting alternative organ processes to handle lead intoxication.

Valor del líquido pericárdico con relación a la biopsia pericárdica en el diagnóstico de pericarditis efusiva tuberculosa / Value of I eliminate pericardico in relation to the pericárdica biopsy in the diagnosis of tuberculosa efusiva pericarditis

Objetivo: Determinar el valor del líquido pericárdico con relación a la biopsia pericárdica en la pericarditis efusiva tuberculosa y el grado de concordancia entre el diagnóstico por líquido pericárdico y el diagnóstico por biopsia pericárdica. Material y métodos: Se analizaron retrospectivamente las historias clínicas de 19 pacientes con diagnóstico pre-operatorio de pericarditis efusiva, entre los años 1994 y 1999, que acudieron al servicio de cirugía de Tórax y Cardiovascular del Hospital Nacional Cayetano Heredia. Se consideró diagnóstico confirmado de pericarditis tuberculosa a los pacientes que cumplían los siguientes criterios por estudio de líquido pericárdico (cultivo positivo para Bacilo de Koch o examen directo de Bacilo de Koch positivo o valor de ADA mayor a 50 UI/L) y/o los siguientes criterios por estudio de biopsia pericárdica (Cultivo positivo para Bacilo de Koch y granuloma con necrosis caseosa o presencia de células gigantes multinucleadas tipo Langhans o presencia de BAAR en la muestra). Resultados: De los 19 pacientes con diagnóstico de pericarditis efusiva. 12 pacientes tuvieron el diangóstico confirmado de pericarditis tuberculosa, según criterios establecidos. De estos 12 pacientes, solo 6 pacientes cumplieron con ambos criterios, 5 pacientes solo con los criterios por estudio de líquido pericárdico, y un paciente, solo con los criterios por estudio de biopsia pericárdica. Se obtuvo una sensibilidad y especificidad para el estudio del líquido pericárdico de 85.7 por ciento y 58.3 por ciento respectivamente, con un valor predictivo positivo y valor predictivo negativo de 54.5 por ciento y 87.5 por ciento respectivamente. Además se encontró un grado de concordancia entre ambos métodos diagnósticos de 0.394. Conclusión: El estudio de líquido pericárdico en la pericarditis efusiva tuberculosa, tiene mayor utilidad para descartar dicha etiología que para confirmarla, por lo que es mandatoria la necesidad de obtener una biopsia de tejido pericárdico para confirmar la etiología tuberculosa.

Un método para la evaluación de riesgos para la salud en zonas mineras / Health risk assessment of minig sites

Objetivo. En este trabajo se propone un esquema de tres fases para evaluar el riesgo en salud en las zonas mineras. La validación del esquema se efectuó en una zona de San Luis Potosí, México. Material y métodos. El monitoreo incluyó análisis de metales en suelo superficial, polvo residencial y agua de pozos. La biodisponibilidad se midió como el nivel de arsénico urinario en niños de las áreas contaminadas. La evaluación toxicológica consistió en análisis de la hepatotoxicidad (niveles de aspartato transaminasa) y neurotoxicidad (niveles de dopamina y de sus metabolitos) en ratas tratadas con residuos mineros. Resultados. Se encontró contaminación por arsénico y plomo en suelo y polvo. La biodisponibilidad fue positiva: 71 por ciento de los niños analizados tuvieron niveles urinarios de arsénico por arriba del valor normal. Los estudios de toxicidad mostraron daño hepático y alteraciones neuroquímicas en las ratas tratadas con el residuo. Conclusiones. El método fue útil para demostrar el riesgo en salud y para que las autoridades decidieran instrumentar un programa de restauración en la zona

Eficacia del cepillo cervical en obtención de muestra endocervical en comparación con el abatelenguas / Effectiveness of cervical brush in obtaining en do cervical sample as compared to tongue holder

A través de un estudio cuasi experimental se comparó la eficacia del cepillo cervical en la obtención de la muestra endocervical con la del abatelenguas en tres Unidades Médicas de la Delegación Estatal Guerrero del IMSS. Se evaluaron 584 muestras de Papanicolaou tomadas durante el mes de mayo de 1994. En forma aleatoria simple, se realizaron las detecciones usando cepillo o abatelenguas. La técnica para obtener la muestra con el cepillo fue de cinco rotaciones siguiendo las manecillas del reloj. La calidad se evaluó según el sistema Bethesda. Las muestras de Papanicolau tomadas con cepillo incrementaron considerablemente su calidad en relación al uso del abatelenguas. Existe 4 veces más riesgo de obtener una muestra de mala calidad cuando se utiliza el abatelenguas

Estrategia de contratación permanente dentro del Programa de Vacunación Universal / A strategy of permanent personnel employment within the Universal Vaccination Progaram

Objetivo. Evaluar los resultados de una estrategia para la vacunación en niños menores de un año, tendiente a elevar la cobertura de esquemas completos y mejorar la captación temprana. Material y métodos. En Tixtla, Guerrero, México, de abril a diciembre de 1994 se estudiaron dos áreas geoestadísticas básicas (AGEB) con un promedio de 100 niños menores de un año en cada una. En el área de intervención se contrató permanentemente a personas de la comunidad para la captación temprana (antes de los dos meses de edad) y vacunación oportuna de niños con esquemas incompletos de vacunación (de acuerdo con su edad). En el área de control se continuó con campañas periódicas. Resultados. La estrategia de intervención elevó el porcentaje de esquemas completos de vacunación (de acuerdo con la edad) de 21.1 a 93.5 por ciento en niños menores de un año, así como la captación temprana. Conclusiones. Esta estrategia puede ayudar a lograr una mejor cobertura de vacunación en áreas urbanas

Objective. To evaluate the results of a vaccination strategy on children under one year of age, aimed at increasing the coverage of the complete vaccination scheme, and at improving early entry into the program. Material and methods. In Tixtla, Guerrero, Mexico, from April to December 1994, two basic geostatistical areas (BGSA) were studied. Each area had an average number of 100 children under one year of age. In the area of intervention, people from the community were hired on a permanent basis for early recruitment of children (under two months of age) and for appropriate vaccination of children with incomplete vaccination schemes. In the control area vaccination campaigns were offered periodically. Results. It was found that the strategy of intervention increased the percentage of completed vaccination schemes, from 21.1% to 93.5% among children under one year of age, as well as the recruitment rate. Conclusions. This strategy can help to achieve a better coverage of vaccination programs in urban areas where coverage is low.

Abandono del tratamiento antituberculoso: factores asociados / Desertion of antituberculosis treatment: associated elements

Se trata de establecer la asociación entre el abandono del tratamiento entituberculoso y las características individuales del paciente y de los servicios de salud en población del Instituto Mexicano del Seguro Social en Acapulco, Guerrero. A través de un estudio de casos y controles se analizaron 50 pacientes que abandonaron el tratamiento antituberculoso entre el 1 de enero de 1990 y el 30 de junio de 1992; los controles fueron 107 pacientes escogidos en forma aleatoria que terminaron en el mismo periodo. La unidad de adscripción fue el factor que con mayor significación se asoció al abandono del tratamiento antituberculoso. El desconocimiento que el paciente tiene de su enfermedad se asoció significativamente con el abandono del tratamiento cuando se estratificó por migración, apoyo familiar y desconfianza hacia el médico en su acierto para tratar la enfermedad. Se construyó el perfil del paciente que abandonó el tratamiento mediante un modelo de regresión logística

A gerência nos sistemas locais de saúde: estudo do processo de direçäo no sistema de saúde de Santos, S.P. (Säo Paulo) / The management in health local systems: direction process study in Santos' health system (Brazil)

Estuda a aplicaçäo dos processos gerenciais na implementaçäo dos Sistemas Locais de Saúde (SILOS) dentro dos sistemas de saúde. Verifica a importância de contar com instrumentos de gerência que facilitem e orientem o trabalho dos administradores de saúde e que permitam o diálogo e análise conjunta com os diversos atores comunitários. Acompanha o papel da gerência na implementaçäo dos sistemas locais de saúde e estuda o processo de direçäo como ferramenta da gerência, nesses sistemas. Busca perceber os pontos fortes e fracos do processo de direçäo no sistema local de saúde de Santos