Osteoinductive activity of photobiomodulation in an organotypic bone model.

Photobiomodulation (PBM) is a technique that harnesses non-ionizing light at specific wavelengths, triggering the modulation of metabolic pathways, engendering favourable biological outcomes that reduce inflammation and foster enhanced tissue healing and regeneration. PBM holds significant promise for bone tissue applications due to its non-invasive nature and ability to stimulate cellular activity and vascularization within the healing framework. Notwithstanding, the impact of PBM on bone functionality remains largely undisclosed, particularly in the absence of influencing factors such as pathologies or regenerative therapies. This study aims to investigate the potential effects of PBM using red (660 nm) (RED) and near-infrared (808 nm) (NIR) wavelengths within an ex vivo bone culture system - the organotypic embryonic chicken femur model. A continuous irradiation mode was used, administering a total energy dose of 1.0 J, at an intensity of 100 mW for 10 s, which was repeated four times over the course of the 11-day culture period. The primary focus is on characterizing the expression of pivotal osteoblastic genes, the maturation and deposition of collagen, and the formation of bone mineral. Exposing femora to both RED and NIR wavelengths led to a notable increase in the expression of osteochondrogenic transcription factors (i.e., SOX9 and RUNX2), correlating with enhanced mineralization. Notably, NIR irradiation further elevated the expression of bone matrix-related genes and fostered enhanced deposition and maturation of fibrillar collagen. This study demonstrates that PBM has the potential to enhance osteogenic functionality within a translational organotypic bone culture system, with the NIR wavelength showing remarkable capabilities in augmenting the formation and maturation of the collagenous matrix.

Glandular Odontogenic Cyst in the Anterior Mandible: A Case Report of a Conservative Approach and a Recurrence Detection.

PURPOSE: The glandular odontogenic cyst (GOC) is considered a rare developmental cyst, with an odontogenic origin and both epithelial and glandular characteristics, with less than 200 reported cases in the literature. METHODS: In the present case, a 29-year-old man was referred for evaluation of an asymptomatic slow-growing swelling in the anterior region of the mandible, with one-year history. The patient's medical history did not reveal any systemic alteration. The extraoral examination did not show enlargement of the facial contour and the intraoral examination showed vestibular and lingual swelling. Panoramic radiography and CT scan revealed a well-defined unilocular radiolucent lesion involving the inferior incisors and canines bilaterally. RESULTS: Histopathological analysis revealed multiple cysts lined by stratified epithelium with varying thickness and characteristics, in addition to duct-like structures filled with PAS-positive amorphous material, suggestive of GOC. Conservative treatment was performed through surgical curettage, peripheral ostectomy of the surgical site and apicectomy of the teeth involved in the lesion. There was one recurrence, which was detected in postoperative follow-up, leading to a new surgical approach. CONCLUSIONS: Fifteen months after the second procedure, no signs of recurrence were identified, and bone neoformation within the surgical site occurred, supporting that a conservative approach for the treatment of GOC is viable.

Evaluación de la satisfacción de pacientes en cesación de tabaquismo mediante la utilización de telemedicina en la Cátedra y Servicio de Neumología del Hospital de Clínicas / Evaluation of the patient's satisfaction in smoking cessation through the use of telemedicine in the Chair and Department of Pneumology of the Hospital de Clínicas

El tabaquismo es una importante causa de enfermedad y muerte debido a neoplasias, enfermedades cardiovasculares y pulmonares, provocando además disminución de la productividad y aumento de la pobreza. La telemedicina es una de las innovaciones principales en los servicios de salud, especialmente en el contexto de la pandemia de COVID19 que dificulta la atención presencial. Se ha evidenciado en los pacientes, un grado de satisfacción elevado, un aspecto importante al momento de valorar la calidad de la atención médica prestada y justificar las innovaciones

Smoking is an important cause of illness and death due to neoplasms, cardiovascular and pulmonary diseases, also causing a decrease in productivity and an increase in poverty. Telemedicine is one of the main innovations in health services, especially in the context of the COVID19 pandemic that makes face-to-face care difficult. A high degree of patient satisfaction has been evidenced, an important aspect when assessing the quality of medical care provided and justifying innovations

The Embryonic Chick Femur Organotypic Model as a Tool to Analyze the Angiotensin II Axis on Bone Tissue.

Activation of renin-angiotensin system (RAS) plays a role in bone deterioration associated with bone metabolic disorders, via increased Angiotensin II (AngII) targeting Angiotensin II type 1 receptor/Angiotensin II type 2 receptor (AT1R/AT2R). Despite the wide data availability, the RAS role remains controversial. This study analyzes the feasibility of using the embryonic chick femur organotypic model to address AngII/AT1R/AT2R axis in bone, which is an application not yet considered. Embryonic day-11 femurs were cultured ex vivo for 11 days in three settings: basal conditions, exposure to AngII, and modulation of AngII effects by prior receptor blockade, i.e., AT1R, AT2R, and AT1R + AT2R. Tissue response was evaluated by combining µCT and histological analysis. Basal-cultured femurs expressed components of RAS, namely ACE, AT1R, AT2R, and MasR (qPCR analysis). Bone formation occurred in the diaphyseal region in all conditions. In basal-cultured femurs, AT1R blocking increased Bone Surface/Bone Volume (BS/BV), whereas Bone Volume/Tissue Volume (BV/TV) decreased with AT2R or AT1R + AT2R blockade. Exposure to AngII greatly decreased BV/TV compared to basal conditions. Receptor blockade prior to AngII addition prevented this effect, i.e., AT1R blockade induced BV/TV, whereas blocking AT2R caused lower BV/TV increase but greater BS/BV; AT1R + AT2R blockade also improved BV/TV. Concluding, the embryonic chick femur model was sensitive to three relevant RAS research setups, proving its usefulness to address AngII/AT1R/AT2R axis in bone both in basal and activated conditions.

Peligros en la utilización de cabinas de desinfección contra el SARS-CoV-2 / Hazards in the use of disinfection cabinets against SARS-CoV-2

La pandemia producida por el coronavirus SARS-CoV-2 está causando estragos sanitarios y económicos en todo el mundo, obligando a la reorientación de recursos para disminuir el contagio y superar los problemas económicos. En ese sentido se comenzaron a construir y emplear las cabinas de desinfección para eliminar el SARS-CoV-2 de forma externa, las cuales eran colocadas en las entradas de los hospitales para rociar con agentes desinfectantes a las personas que entraban y salían del lugar, a pesar de que los productos empleados están habilitados para ser utilizados sobre objetos y por un tiempo determinado, lo cual representaba un riesgo para la salud del usuario por lo que se requería de un estudio para establecer los peligros relacionados y desaconsejar su utilización.

The pandemic produced by the SARS-CoV-2 coronavirus is causing health and economic havoc throughout the world, forcing the redirection of resources to reduce contagion and overcome economic problems. In this sense, they began to build and use disinfection cabins to eliminate SARS-CoV-2 externally, which were placed at the entrances of hospitals to spray disinfectants with disinfectants to people who entered and left the place, despite the fact that the products used are enabled to be used on objects and for a certain time, which represented a risk to the health of the user, so a study was required to establish the related dangers and advise against their use.

Frecuencia y perfil del uso de cigarrillos electrónicos en estudiantes de una Universidad Pública / Frequency and profile of the electronic cigarettes use in students of a Public University

Introducción: El consumo de Cigarrillos electrónicos (CE) ha aumentado considerablemente en los últimos años. Estos productos son ahora los más comúnmente utilizados por la juventud en diversos países del mundo y nuestro país no está exento de su utilización. En este contexto se ha realizado el presente estudio; cuyo objetivo fue conocer la frecuencia de uso de cigarrillo electrónico y otras características del consumo de CE en universitarios. Materiales y Métodos: Estudio observacional, descriptivo. Se procesaron datos de 1500 estudiantes de diferentes Unidades Académicas de la UNA que respondieron a la encuesta electrónica. Se determinaron variables demográficas como sexo y edad, particularidades sobre los CE relacionadas a la preferencia por determinado dispositivo, motivaciones para el consumo, simultaneidad de consumo de cigarrillo común, así como la percepción de riesgo con respecto al mismo y las molestias ocasionadas por vapear. La encuesta fue anónima y realizada entre los meses de junio y julio del año 2019 mediante la plataforma libre Google Form. Para el procesamiento de datos se utilizó la planilla Excel. Los estudiantes recibieron vía aplicación de mensajería instantánea un link para responder el cuestionario, el mismo fue distribuido por grupos de docentes y delegados de los cursos de cada unidad académica. Resultados: Respondieron a la encuesta un total de 1500 alumnos, 502 hombres (33,5%) y 998 mujeres (66,5%). El promedio de edad fue de 24 años (DE: ± 3.2), con edades comprendidas entre los 17 y 62 años. Al preguntar sobre el hábito de fumar o vapear los estudiantes respondieron: No fuma ninguno 1222 (81 %), consume cigarrillos electrónicos: 74(5 %), 146 (10%) consumen cigarrillo común y un total de 58(4%) consumen ambos productos. Considerando el total de consumidores de CE y aquellos que utilizan ambos (CE y Cigarrillo común), tenemos una frecuencia de 132 consumidores de CE (9%). Percepción de riesgo con respecto a cigarrillos comunes: Ningún riesgo 32 (24%), pequeño riesgo: 54 (41%), riesgo moderado: 34 (26%), alto riesgo: 9 (7%) e igual riesgo: 3 (2%). Entre las molestias más frecuentes: tos 27 (20%), irritación de garganta 20 (15%), dolor de cabeza 6 (5 %) y malestar general 4 (3%). Conclusión: El uso de CE se aproxima al consumo de cigarrillo común y los universitarios no son conscientes sobre los daños potenciales que confiere el uso de estos dispositivos. Para prevenir y reducir el uso de cigarrillos electrónicos por los jóvenes y los adultos jóvenes debemos poner en práctica estrategias de prevención efectivas.

Introduction: The consumption of Electronic Cigarettes (EC) has increased considerably in recent years. These products are now the most commonly used by youth in various countries of the world and our country is not exempt from their use. In this context, the present study has been carried out; whose objective was to know the frequency of use of electronic cigarettes and other characteristics of CE consumption in university students. Materials and methods: Observational, descriptive study. Data from 1500 students from different UNA Academic Units that responded to the electronic survey were processed. Demographic variables such as sex and age, peculiarities on EC related to the preference for a certain device, motivations for consumption, simultaneity of consumption of common cigarettes, as well as the perception of risk with respect to it and the discomfort caused by vaping were determined. The survey was anonymous and carried out between the months of June and July of the year 2019 through the free platform Google Forms. The Excel spreadsheet was used for data processing. The students received a link via instant messaging application to answer the questionnaire, it was distributed by groups of teachers and delegates of the courses of each academic unit. Results: A total of 1500 students answered the survey, 502 men (33.5%) and 998 women (66.5%). The average age was 24 years (SD: ±16), with ages between 17 and 62 years. When asked about the habit of smoking or vaping, the students answered: 1222 (81%) do not smoke, use electronic cigarettes: 74 (5%), 146 (10%) use a regular cigarette and a total of 58 (4%) use both products. Considering the total of EC consumers and those who use both (EC and Common Cigarette), we have a frequency of 132 EC consumers (9%). Perception of risk with respect to common cigarettes: No risk 32 (24%), small risk: 54 (41%), moderate risk: 34 (26%), high risk: 9 (7%) and equal risk: 3 (2 %). Among the most frequent complaints: cough 27 (20%), throat irritation 20 (15%), headache 6 (5%) and general discomfort 4 (3%). Conclusion: The use of EC is close to the consumption of common cigarettes and the university students are not aware of the potential damage that the use of these devices confers. To prevent and reduce the use of electronic cigarettes by youth and young adults, we must implement effective prevention strategies.

Preparation of Sesquiterpene Lactone Derivatives: Cytotoxic Activity and Selectivity of Action.

Cancer is one of the most important causes of death worldwide. Solid tumors represent the great majority of cancers (>90%) and the chemotherapeutic agents used for their treatment are still characterized by variable efficacy and toxicity. Sesquiterpene lactones are a group of naturally occurring compounds that have displayed a diverse range of biological activities including cytotoxic activity. A series of oxygenated and oxy-nitrogenated derivatives (4⁻15) from the sesquiterpene lactones cumanin (1), helenalin (2), and hymenin (3) were synthesized. The silylated derivatives of helenalin, compounds 13 and 14, were found to be the most active against tumor cell lines, with GI50 values ranging from 0.15 to 0.59 µM. The ditriazolyl cumanin derivative (11) proved to be more active and selective than cumanin in the tested breast, cervix, lung, and colon tumor cell lines. This compound was the least toxic against splenocytes (CC50 = 524.1 µM) and exhibited the greatest selectivity on tumor cell lines. This compound showed a GI50 of 2.3 µM and a SI of 227.9 on WiDr human colon tumor cell lines. Thus, compound 11 can be considered for further studies and is a candidate for the development of new antitumor agents.

Assessment of the external load of amateur soccer players during four consecutive training microcycles in relation to the external load during the official match

Aim: The aim of this study was to assess the external load of amateur male players during 4 consecutive training microcycles (M) at the beginning of the in-season according to the training session in absolute external load demands and in relation to the competition demands. Methods: Regional-level players (n = 10; age, 20.8 ± 1.7 years; height, 175.5 ± 3.8 cm; body mass, 69.7 ± 2.9 kg; soccer experience, 13.2 ± 2.5 years) were monitored using GPS devices during training sessions and matches. The external load variables measured were: duration (min); total distance covered (TD); distance covered at high-speed (HID, 14.4-19.8 km/h); distance covered at sprinting (SPD; >19.8 km/h); and distance covered in high intensity acceleration (ACD; >2.5 m/s2) and deceleration (DECD; <-2.5 m/s2). Results: The results indicated that the external load variables (time, HID, SPD, ACD, and DECD) were similar between the four microcycles. Greater (p<0.01) time, TD, HID and SPD were observed in match day (MD)-2 compared to MD+1, MD-3, and MD-1. Aside from training duration, all external loads variables (TD, HID, SPD, ACD, and DECD) were lower during training sessions compared to official matches (p<0.05). Conclusion: Amateur soccer players present relative stable external training loads across competitive microcycles, with the peak load observed two days before the official match. Besides this, the match constitutes the highest load during a typical competitive microcycle in this cohort of players.(AU)

La Extensión universitaria como herramienta para mejorar conocimientos de pacientes con diabetes e hipertensión / The University extension as a tool to improve knowledge of patients with diabetes and hypertension

Introducción: Las enfermedades crónicas no transmisibles (ECNT) son las principales causas de muerte en el mundo, que corresponde al 26% de las muertes en nuestro país y su prevalencia se ha incrementado en un 10 % en los últimos 15 años. La forma de prevenir y controlar las ECNT es a través de una acción global e integrada. La extensión universitaria es un proceso pedagógico transformador en el que alumnos y docentes pueden influir en los estilos de vida de la población, mediante proyectos de intervención comunitaria. Metodología: El proyecto se desarrollo en 3 fases; la primera fase de diagnostico y primera encuesta sobre conocimiento de ECNT, la segunda de intervención y una tercera donde se aplico una segunda encuesta. Resultados: El proyecto se extendió en el año 2017 con 4 visitas. Dando como resultados los siguientes datos socios demográficos: 36 familias estables, 59 habitantes corresponden al género femenino y 54 al masculino. El 97% son paraguayos. 38,5% finalizo la primaria. En el sexo masculino la profesión fue de empleados 34,6%, de comerciante 18,6%; en el sexo femenino fue de quehaceres domésticos 63,4%. La jefatura de hogar masculina predomina en un 75% el sexo masculino. La patología predominante en adultos es la de HTA. Luego de aplicadas las intervenciones educativas se logró mejorar el conocimiento sobre la diabetes de nivel de conocimiento malo a regular y respecto a la hipertensión el nivel de conocimiento aumento de regular a buena. Conclusión: Los pacientes mejoraron el conocimiento sobre las ECNT, por lo cual se demostró el beneficio de la intervención mediante este proyecto de extensión universitaria.

Introduction: Chronic noncommunicable diseases (NCDs) are the main causes of death in the world, which corresponds to 26% of deaths in our country and its prevalence has increased by 10% in the last 15 years. The way to prevent and control CNCDs is through a global and integrated action. The university extension is a transformative pedagogical process in which students and teachers can influence the lifestyles of the population through community intervention projects. Methodology: The project was developed in 3 phases; the first phase of diagnosis and first survey on knowledge of NCDs, the second of intervention and a third where a second survey was applied. Results: The project was extended in 2017 with 4 visits. Giving as results the following data demographic partners: 36 stable families, 59 inhabitants correspond to the feminine gender and 54 to the masculine. 97% are Paraguayan. 38.5% finished primary school. In the male sex, the profession was 34.6% employees, 18.6% merchant; in the female sex, it was household chores 63.4%. The male head of household dominates the male sex by 75%. The predominant pathology in adults is that of HTN. After applying the educational interventions, it was possible to improve the knowledge about diabetes from the level of bad knowledge to regular and regarding hypertension, the level of knowledge increased from regular to good. Conclusion: Patients improved their knowledge about CNCDs, which is why the benefit of the intervention was demonstrated through this university extension project.

Evaluación de la aceptabilidad, reproductividad y calidad de las espirometrías realizadas en un servicio neumológico de adultos / Evaluation of the acceptability, reproducibility and quality of spirometry performed in an adult pneumology service

Las enfermedades pulmonares requieren estudios auxiliares de gran precisión. La espirometría es una prueba diagnóstica y de seguimiento de mucha importancia en el manejo de las patologías respiratorias, especialmente las obstructivas. Esta investigación presenta las indicaciones de su uso, y evaluó los errores en las espirometrías de 70 pacientes realizadas en un consultorio neumológico, considerando los criterios de aceptabilidad, reproductividad y calidad. Se detectó que más del 95% de espirometrías alcanzan el nivel de buena calidad, siendo este dato similar al de estudios más amplios. Los errores más frecuentes fueron la terminación temprana del procedimiento y diferencia no aceptable entre las principales variables medidas. Es una gran preocupación de las sociedades científicas neumológicas garantizar que estos estudios tengan la máxima fiabilidad posible, para eso es importante un monitoreo periódico de la calidad de las espirometrías y así asegurar que tengan la mayor utilidad, con profesionales sanitarios adecuadamente formados para el efecto.

Pulmonary diseases require very precise auxiliary studies. Spirometry is a diagnostic and monitoring test of great importance in the management of respiratory pathologies, especially obstructive ones. This research presents the indications of its use, and evaluated the errors in the spirometry of 70 patients performed in a pulmonology clinic, considering the criteria of acceptability, reproducibility and quality. It was detected that more than 95% of spirometries reach the level of good quality, this data being similar to that of larger studies. The most frequent errors were the early termination of the procedure and a not acceptable difference between the main variables measured. It´s a great concern of pulmonological scientific societies to ensure that these studies have the highest possible reliability, for that reason, it´s important to periodically monitor the quality of spirometries and thus ensure that they have the greatest utility, with health professionals adequately trained for this purpose.

Direct Access to 2,3,4,6-Tetrasubstituted Tetrahydro-2H-pyrans via Tandem SN2'-Prins Cyclization.

A new, direct, and diastereoselective synthesis of activated 2,3,4,6-tetrasubstituted tetrahydro-2H-pyrans is described. In this reaction, iron(III) catalyzed an SN2'-Prins cyclization tandem process leading to the creation of three new stereocenters in one single step. These activated tetrahydro-2H-pyran units are easily derivatizable through CuAAC conjugations in order to generate multifunctionalized complex molecules. DFT calculations support the in situ SN2' reaction as a preliminary step in the Prins cyclization.

Mass spectrometry studies of lycodine-type Lycopodium alkaloids: sauroxine and N-demethylsauroxine.

RATIONALE: Sauroxine and N-demethylsauroxine are lycodine-type Lycopodium alkaloids. In recent years, Lycopodium alkaloids have gained significant interest due to their unique skeletal characteristics as well as due to their acetylcholinesterase activity. It is known that drugs that inhibit acetylcholinesterase can be used to treat the early stages of Alzheimer's disease. METHODS: Sauroxine and N-demethylsauroxine were isolated from the aerial parts of Huperzia saururus (Lam.) Trevis. Electron ionization mass spectrometry (EI-MS) (low resolution) and collision-induced dissociation tandem mass spectrometry (CID-MS/MS) fragmentation was conducted using an ion trap, GCQ Plus mass spectrometer with MS/MS. Electron ionization high-resolution mass spectrometry (EI-HRMS) was performed in a magnetic sector mass spectrometer (Micromass VG). RESULTS: Using GC/EI-CID-MS/MS we obtained different fragmentation routes that connect all the ionic populations. In addition, the use of EI-HRMS allowed us to measure the exact masses of all the fragment ions, and, with all this information gathered, we tried to establish a fragmentation scheme concordant with the ascendant and descendant species. CONCLUSIONS: The mass spectrometry studies presented in this work complete our mass studies of Lycopodium alkaloids. The mass spectrometry work presented has been very useful to confirm the structures as well as to support the biogenetic relationships between the lycodine-type Lycopodium alkaloids: sauroxine and N-demethylsauroxine.

Derivatives of grindelic acid: from a non-active natural diterpene to synthetic antitumor derivatives.

Using several reactions that include homologations and asymmetric epoxidations as well as Ugi and Huisgen couplings, we generated a small focused library of new derivatives from the labdane-type diterpene grindelic acid. These compounds were evaluated as cytotoxic agents against a panel of five human solid tumor cell lines (HBL-100, HeLa, SW1573, T-47D, and WiDr). The presence of the diamide functionalizations enhanced the cytotoxic effect. N-Benzyl-N-(1-(benzylamino)-2-methyl-1-oxopropan-2-yl)grindelicamide, proved to be the most active product in all cell lines tested, with values of 0.95 (±0.38) µM against HBL-100 cells.

Analysis of cocaine and benzoylecgonine in urine by using multisyringe flow injection analysis-gas chromatography-mass spectrometry system.

In this paper, a method was described to determine cocaine (COC) and benzoylecgonine (BZE) in human urine samples by GC-MS detection. The extraction of analytes from urine samples was achieved in an Oasis hydrophilic-lipophilic balance column (20 mmx3.9 mm id, dp=25 microm; Waters, USA), incorporated in a multisyringe flow injection system, used for the sample treatment. Finally, to improve the volatility of the BZE, an in-line derivatization reaction with N,O-bis (trimethylsilyl) trifluoroacetamide with 1% trimethylchlorosilane was made microwave-assisted in order to reduce the reaction time. The results showed that the proposed method is a good alternative for the analysis of COC and BZE in urine samples because it offers advantages compared with those described in the literature, which include simplicity in the sample treatment, the sensitivity and selectivity necessary to determine the analytes of interest at low levels in the urine and high sample throughput.

Development and validation of a rapid column-switching high-performance liquid chromatographic method for the determination of Lamotrigine in human serum.

This study describes a simple and sensitive column-switching high-performance liquid chromatographic method with UV detection for the determination of Lamotrigine in 50 microL of serum. After solid-phase extraction of Lamotrigine on an Oasis HLB extraction precolumn (20 x 3.9 mm; dp: 25 microm), chromatographic separation was achieved at 30 degrees C on a Chromolith RP-18e column (50 mm x 4.6 mm i.d.) using a solution of 20% acetonitrile in 15 mM phosphate buffer (pH 7.0) as the mobile phase, at a flow-rate of 2.0 mL/min. The eluant was detected at 215 nm. The retention time for Lamotrigine was 1.28 min. The total analysis time was ca. 5 min. However, the overlap of sample preparation, analysis, and reconditioning of the precolumn increased the overall sample throughput to one injection every 3 min. The method was validated for system suitability, linearity, precision, accuracy, robustness, and limit of quantitation. The linearity of the calibration lines, expressed by the linear correlation coefficient, was better than 0.9996. Recovery studies achieved from Lamotrigine spiked plasma samples showed values greater than 93%, demonstrating the excellent extraction efficiency of the precolumn. Intra- and inter-day precision were generally acceptable; the coefficient of variation was < 2.3% in all cases. The detection limits for Lamotrigine at a signal-to-noise ratio of 3 was 0.002 microg/mL when a sample volume of 50 microL was injected. However, it was possible to enhance the sensitivity further by injecting larger volumes, up to 200 microL. The method was shown to be robust and the results were within the acceptable range. The method was successfully applied to the determination of Lamotrigine in human serum samples of patients submitted to Lamotrigine therapy.

Determination of losartan, telmisartan, and valsartan by direct injection of human urine into a column-switching liquid chromatographic system with fluorescence detection.

Column-switching high-performance liquid chromatographic (HPLC) method has been developed and validated for quantification of losartan, telmisartan, and valsartan in human urine. Urine samples were diluted on the extraction mobile phase (1:4, v/v) and a volume of 20 microL of this mixture were directly injected onto the HPLC system. The analytes were extracted from the matrix using an on-line solid-phase extraction procedure involving a precolumn packed with 25 microm C(18) alkyl-diol support (ADS), and a solution 2% methanol in 5mM phosphate buffer (pH 3.8) at a flow-rate of 0.8 mL/min for isolation and preconcentration of losartan, telmisartan, and valsartan. The enriched analytes were back-flushed after, onto the analytical column with a mixture of 5mM phosphate buffer (pH 3.8)-acetonitrile-methanol (65:20:15, v/v/v) at a flow-rate of 3.0 mL/min and detected by fluorescence at 259 and 399 nm as excitation and emission wavelength respectively. The separation of losartan, telmisartan, and valsartan was achieved on a Chromolith RP-18e monolithic column. The method provides extraction recoveries from spiked urine samples greater than 93%. Intra-day and inter-day precision were generally acceptable; the intra-day-assay C.V. was <3.5 for all compounds and the inter-day-assay C.V. was < 3.7%. The estimated calibration range was 0.001-2.5 microg/mL(-1) with excellent coefficient of determination (>0.9981). The detection limits for losartan, telmisartan, and valsartan at a signal-to-noise ratio of 5:1 were 0.002, 0.0002 and 0.001 microg/mL(-1) when a sample volume of 20 microL was injected. The proposed method permitted the simultaneous determination of losartan, telmisartan, and valsartan in 8 min, with an adequate precision and sensitivity. However, the overlap of the sample cleanup step with the analysis increases the sampling frequency to 12 samples/h. The developed column-switching method was successfully applied for the determination of these analytes in human urine samples of patients submitted at ARA-IIs therapy.

Insect growth regulatory effects of linear diterpenoids and derivatives from Baccharis thymifolia.

Linear diterpenes isolated from aerial parts of Baccharis thymifolia ( 1- 3) were tested for insect growth inhibitory activity against Tenebrio molitor larvae. Compounds 4- 16 were prepared by various chemical transformations. The diterpenes 6,10-( E,E)-thymifodioic acid ( 1), the butenolide 3, and the derivatives 4, 11, and 14 produced developmental deficiencies in assays using topical application on fifth instar larvae of T. molitor. Compound 3 is a new natural product.

Development of a new high performance low pressure chromatographic system using a multisyringe burette coupled to a chromatographic monolithic column.

A novel combination of high performance low pressure chromatography with multisyringe flow injection analysis is presented. This system comprises a multisyringe module, three low pressure solenoid valves, a monolithic Chromolith Flash RP-18e column and a diode array spectrophotometer. UV detection is carried out at 250nm. AutoAnalysis software is used for instrumental control and automated data collection. The results obtained with multisyringe liquid chromatography (MSC) were compared with those obtained with a HPLC system using similar conditions. The chromatographic parameters were calculated from a mixture of anthracene and thiourea using a mobile phase containing acetonitrile-water (60:40) at a flow rate of 2mlmin(-1). The proposed MSC system has been successfully applied to the determination of amoxicillin, ampicillin and cephalexin using a mobile phase of sodium acetate buffer (pH 6.2, 0.1moll(-1))-methanol (90:10) at a flow rate of 2mlmin(-1). The low-cost, flexibility and simplicity of MSC should be highlighted.

Los niños y el tabaco / Children and tobacco

Presenta la problematica del consumo del tabaco en Paraguay, el aumento el los ultimos años y los efectos del tabaquismo pasivo en los niños paqueños