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Purpose: To show the workflow for the commissioning of a MRlinac, and some proposed tests; off-axis targets, output factors for small fields, dose in inhomogeneities, and multileaf collimator quality assurance (MLC QA). Methods: The tests were performed based on TG-142, TG-119, ICRU 97, TRS-398, and TRS-483 recommendations as well as national regulations for radiation protection and safety. Results: The imaging tests are in agreement with the protocols. The radiation isocenter was 0.34 mm, and for off-axis targets location was up to 0.88 mm. The dose profiles measured and calculated in treatment planning system (TPS) passed in all cases the gamma analysis of 2%/2 mm (global dose differences). The output factors of fields larger than 2 cm × 2 cm are in agreement with the model of the MRlinac in the TPS. However, for smaller fields, their differences are higher than 10%. Picket fence test for different gantry angles showed a maximum leaf deviation up to 0.2 mm. Displacements observed in treatment couch adding weight (50 kg) are lower than 1 mm. Cryostat, bridge, and couch attenuation was up to 1.2%, 10%, and 24%, respectively. Conclusion: The implemented tests confirm that the studied MRlinac agrees with the standards reported in the literature and that the strict tolerances established as a baseline should allow a smoother implementation of stereotactic treatments in this machine.
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PURPOSE: To evaluate the feasibility of use of an 1.5 T magnetic resonance (MR)-linear accelerator MR-linac for imaging in gynaecologic high-dose-rate (HDR) brachytherapy. Method: Commissioning measurements for MR images quality control, geometric distortion, dwell position accuracy, applicator reconstruction and end-to-end test for a tandem-and-ring applicator were performed following the recommendations of American Brachytherapy Society, International Commission on Radiation Units and Measurements and Report of the Brachytherapy Working Group of the Spanish Society of Medical Physics. The values for MR-based IGABT were compared to the corresponding values with computed tomography (CT). Results: Measured distorsions for the MR images were less than 0.50 mm compared to the CT images. The differences between 3D displacements for all dwell positions were 0.66 mm and 0.62 mm for the tandem and ring, respectively. The maximum difference is 0.64 mm for the distances from the applicator tip obtained using the films. The CT and MR dose differences for the right and left 'A' points were 0.9% and -0.7%, respectively. Similar results were observed in terms of dose distribution for CT and MR. The gamma passing rate was 99.3% and 99.5%, respectively. Conclusion: The use of MR images from an MR-linac used in a radiotherapy service for gynaecological brachytherapy was proved to be feasible, safe and precise as the geometrical differences were less than 1 mm, and the dosimetric differences were less than 1% when comparing to the use of CT images for the same purpose.
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Background: Few studies have examined influenza vaccine effectiveness (VE) among women during pregnancy in middle-income countries. We used data from a prospective cohort of women who were pregnant in Peru to estimate effectiveness of the 2018 Southern Hemisphere influenza vaccine. Methods: Women at <28 weeks gestation were enrolled from 4 tertiary level hospitals in Lima, Peru at the start of the 2018 influenza season and followed until the end of their pregnancies. Participants had mid-turbinate nasal swabs collected and tested for influenza by reverse-transcription polymerase chain reaction (RT-PCR) with onset of ≥1 of myalgia, cough, runny nose or nasal congestion, sore throat, or difficulty breathing. Time-varying Cox proportional hazard regression models were used to estimate the risk of RT-PCR-confirmed influenza infection after adjusting for inverse probability treatment weight. Results: We followed 1896 women for a median of 127 days (interquartile range [IQR], 86-174). Participants had a median age of 29 years (IQR, 24-34). Among the 1896 women, 49% were vaccinated with the 2018 influenza vaccine and 1039 (55%) developed influenza-like illness, 76 (7%) of whom had RT-PCR-confirmed influenza. Incidence rates of RT-PCR-confirmed influenza were 36.6 and 15.3 per 100 000 person-days among women who were unvaccinated and vaccinated, respectively. Adjusted influenza VE was 22% (95% confidence interval, -64.1% to 62.9%). Conclusions: Participants vaccinated against influenza had more than 50% lower incidence of RT-PCR-confirmed influenza illness. Although the VE estimated through propensity weight-adjusted time-varying Cox regression did not reach statistical significance, our findings provide additional evidence about the value of maternal influenza vaccination in middle-income countries.
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BACKGROUND: Preeclampsia is a multiorgan disorder associated with maternal and perinatal morbi-mortality. In Peru, incidence is 10% and accounts for 22% of maternal deaths. Genome and genetic epidemiological studies have found an association between preeclampsia and genetic polymorphisms. OBJECTIVE: To determine the association of the vascular endothelial growth factor (VEGF) +936 C/T and +405 G/C, interleukine-6 (IL-6) -174 G/C, IL-1ß-511 C/T, Apo A-1-75 G/A, Apo B-100 2488 C/T (Xbal) polymorphisms with preeclampsia in pregnant Peruvian women. METHODS: Were included preeclamptic and healthy (control) pregnant women. Maternal blood samples were subjected to DNA extraction, and molecular genetic analysis was conducted using the PCR-RFLP technique and following a specific protocol for each gene. Allele and genotypic frequencies in the cases and controls were compared. RESULTS: No association was found between the VEGF+936C/T and VEGF+405 polymorphisms and preeclampsia. The frequencies of the GG genotypes and the G allele of the -174 G/C polymorphism in the IL6 gene in preeclamptic and controls showed significant differences, with higher frequencies in cases. For the -511 C/T polymorphism of the IL-1ß gene, no significant differences were found in the frequencies of TT genotypes compared with CT+CC. The genotypes and alleles of the Apo-A1-75 G/A and Apo-B100 Xbal variants showed no significant differences between cases and controls. CONCLUSION: No association was found between the studied genetic markers and preeclampsia. However, in the -174G/C polymorphism of the IL-6 gene, significant differences were found mainly in the GG genotype and G allele.
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Preeclampsia , Estudios de Casos y Controles , Femenino , Frecuencia de los Genes , Marcadores Genéticos , Predisposición Genética a la Enfermedad , Genotipo , Humanos , Perú/epidemiología , Polimorfismo de Nucleótido Simple , Preeclampsia/epidemiología , Preeclampsia/genética , Embarazo , Factor A de Crecimiento Endotelial Vascular/genéticaRESUMEN
Abstract Background: Preeclampsia is a multiorgan disorder associated with maternal and perinatal morbi-mortality. In Peru, incidence is 10% and accounts for 22% of maternal deaths. Genome and genetic epidemiological studies have found an association between preeclampsia and genetic polymorphisms. Objective: To determine the association of the vascular endothelial growth factor (VEGF) +936 C/T and +405 G/C, interleukine-6 (IL-6) -174 G/C, IL-1β-511 C/T, Apo A-1-75 G/A, Apo B-100 2488 C/T (Xbal) polymorphisms with preeclampsia in pregnant Peruvian women. Methods: Were included preeclamptic and healthy (control) pregnant women. Maternal blood samples were subjected to DNA extraction, and molecular genetic analysis was conducted using the PCR-RFLP technique and following a specific protocol for each gene. Allele and genotypic frequencies in the cases and controls were compared. Results: No association was found between the VEGF+936C/T and VEGF+405 polymorphisms and preeclampsia. The frequencies of the GG genotypes and the G allele of the -174 G/C polymorphism in the IL6 gene in preeclamptic and controls showed significant differences, with higher frequencies in cases. For the -511 C/T polymorphism of the IL-1β gene, no significant differences were found in the frequencies of TT genotypes compared with CT+CC. The genotypes and alleles of the Apo-A1-75 G/A and Apo-B100 Xbal variants showed no significant differences between cases and controls. Conclusion: No association was found between the studied genetic markers and preeclampsia. However, in the -174G/C polymorphism of the IL-6 gene, significant differences were found mainly in the GG genotype and G allele.
Resumen Antecedentes: La preeclampsia es un trastorno multiorgánico asociado con la morbi-mortalidad materna y perinatal. En el Perú, su incidencia es del 10% y causa el 22% de las muertes maternas. Se encontró una asociación entre la preeclampsia y ciertos polimorfismos. Objetivo: Determinar asociación entre los polimorfismos genéticos del factor de crecimiento endotelial vascular (VEGF) +936 C/T y +405 G/C, interleucina-6 (IL-6) -174G/C, IL-1β -511 C/T, Apo A-1 -75 G/A, Apo B-100 2488 C/T (Xbal), y preeclampsia en gestantes peruanas. Métodos: Se incluyeron gestantes preeclámpticas y sanas (controles). Las muestras de sangre fueron procesadas para extracción del ADN, y el análisis se realizó con la técnica PCR-RFLP con protocolos específicos para cada gen y confirmación con secuenciamiento Sanger. Se compararon las frecuencias alélicas y genotípicas en los casos (preeclampsia) y los controles. Resultados: No se halló asociación entre los polimorfismos VEGF+936-C/T y VEGF+405 y la preeclampsia. Las frecuencias de los genotipos GG y el alelo G del polimorfismo -174-G/C en el gen IL6 en preeclámpticas y controles, mostraron diferencias significativas, con frecuencias más altas en los casos. Para el polimorfismo -511-C/T del gen IL-1β, no se encontraron diferencias significativas en las frecuencias de genotipos TT comparados con CT+CC. Los genotipos y alelos de las variantes Apo-A1-75-G/A y Apo-B100 Xbal no mostraron diferencias significativas entre los grupos Conclusión: No se encontró asociación entre los marcadores genéticos estudiados y la preeclampsia. Sin embargo, el polimorfismo -174-G/C en el gen IL6 mostró diferencias significativas principalmente en el genotipo GG y el alelo G.
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Femenino , Humanos , Embarazo , Preeclampsia , Perú/epidemiología , Preeclampsia/genética , Preeclampsia/epidemiología , Marcadores Genéticos , Estudios de Casos y Controles , Predisposición Genética a la Enfermedad , Polimorfismo de Nucleótido Simple , Factor A de Crecimiento Endotelial Vascular/genética , Frecuencia de los Genes , GenotipoRESUMEN
Introduction: We evaluated knowledge, attitudes, and practices (KAP) related to influenza and influenza vaccination among pregnant women in three selected countries.Methods: During 2017, pregnant women seeking antenatal care at hospitals at participating sites were enrolled. We described characteristics and responses to KAP questions. We also evaluated predictors associated with influenza vaccination during pregnancy at sites with substantial influenza vaccine uptake by multivariable logistic regression.Results: Overall, 4,648 pregnant women completed the survey. There were substantial differences among the three survey populations; only 8% of the women in Nagpur had heard of influenza, compared to 90% in Lima and 96% in Bangkok (p-value<0.01). Despite significant differences in sociodemographic characteristics in the three populations, most participants across sites who were aware of influenza prior to study enrollment believe they and their infants are at risk of influenza and related complications and believe influenza vaccination is safe and effective. Half of women in Lima had verified receipt of influenza vaccine compared to <5% in Bangkok and Nagpur (p < .05). For further analysis conducted among women in Lima only, household income above the poverty line (aOR: 1.38; 95%CI: 1.01, 1.88), having 8+ antenatal visits, compared to 0-4 (aOR: 2.41; 95%CI: 1.39, 2.87, respectively), having 0 children, compared to 2+ (aOR: 1.96; 95%CIs: 1.23, 3.12), and vaccination recommended by a health-care provider (aOR: 8.25; 95%CI: 6.11, 11.14) were strongly associated with receipt of influenza vaccine during pregnancy.Conclusions: Our findings identify opportunities for targeted interventions to improve influenza vaccine uptake among pregnant women in these settings.
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Vacunas contra la Influenza , Gripe Humana , Complicaciones Infecciosas del Embarazo , Niño , Estudios Transversales , Femenino , Conocimientos, Actitudes y Práctica en Salud , Humanos , Gripe Humana/prevención & control , Embarazo , Complicaciones Infecciosas del Embarazo/prevención & control , Mujeres Embarazadas , Tailandia , VacunaciónRESUMEN
OBJECTIVE: To determine the minimum blood pressure increases that would confirm or exclude, with the greatest predictive values, hypertensive disorders of pregnancy (HDP) in pregnant adolescents after 24 weeks gestation. METHODS: We conducted a case-control study of pregnant women aged ≤19 years with and without HDP. Using systolic and diastolic blood pressure increases, a predictive analysis was performed, and the area under the curve was calculated. RESULTS: The cases and controls had systolic blood pressure increases of 45.3 ± 17.5 mmâ¯Hg and 6.4 ± 7.9 mmâ¯Hg, respectively (Pâ¯=â¯0.001) and diastolic blood pressure increases of 30.8 ± 11.7 mmâ¯Hg and 3.5 ± 5.7 mmâ¯Hg, respectively (Pâ¯=â¯0.001). Systolic and diastolic increases of ≥20 mmâ¯Hg showed the greatest sensitivity and specificity. A combined analysis showed that an increase of ≥20 mmâ¯Hg had a greater positive likelihood ratio of 35.4 (95% CI 22.4-55.9) and negative likelihood ratio of 0.10 (95% CI 0.07-0.13), with an area under the curve of 0.98 (95% CI 0.96-0.99). CONCLUSIONS: Systolic and diastolic blood pressure increases of ≥20 mmâ¯Hg must be considered in the diagnostic criteria for preeclampsia and gestational hypertension among pregnant adolescents past 24 weeks gestation.
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Presión Sanguínea/fisiología , Hipertensión/diagnóstico , Preeclampsia/diagnóstico , Embarazo en Adolescencia , Adolescente , Monitoreo Ambulatorio de la Presión Arterial , Estudios de Casos y Controles , Femenino , Hospitales , Humanos , Hipertensión/epidemiología , América Latina , Preeclampsia/epidemiología , Valor Predictivo de las Pruebas , Embarazo , Sensibilidad y Especificidad , Adulto JovenRESUMEN
BACKGROUND: Influenza vaccination during pregnancy prevents influenza among women and their infants but remains underused among pregnant women. We aimed to quantify the risk of antenatal influenza and examine its association with perinatal outcomes. METHODS: We did a prospective cohort study in pregnant women in India, Peru, and Thailand. Before the 2017 and 2018 influenza seasons, we enrolled pregnant women aged 18 years or older with expected delivery dates 8 weeks or more after the season started. We contacted women twice weekly until the end of pregnancy to identify illnesses with symptoms of myalgia, cough, runny nose or nasal congestion, sore throat, or difficulty breathing and collected mid-turbinate nasal swabs from symptomatic women for influenza real-time RT-PCR testing. We assessed the association of antenatal influenza with preterm birth, late pregnancy loss (≥13 weeks gestation), small for gestational age (SGA), and birthweight of term singleton infants using Cox proportional hazards models or generalised linear models to adjust for potential confounders. FINDINGS: Between March 13, 2017, and Aug 3, 2018, we enrolled 11â277 women with a median age of 26 years (IQR 23-31) and gestational age of 19 weeks (14-24). 1474 (13%) received influenza vaccines. 310 participants (3%) had influenza (270 [87%] influenza A and 40 [13%] influenza B). Influenza incidences weighted by the population of women of childbearing age in each study country were 88·7 per 10â000 pregnant woman-months (95% CI 68·6 to 114·8) during the 2017 season and 69·6 per 10â000 pregnant woman-months (53·8 to 90·2) during the 2018 season. Antenatal influenza was not associated with preterm birth (adjusted hazard ratio [aHR] 1·4, 95% CI 0·9 to 2·0; p=0·096) or having an SGA infant (adjusted relative risk 1·0, 95% CI 0·8 to 1·3, p=0·97), but was associated with late pregnancy loss (aHR 10·7, 95% CI 4·3 to 27·0; p<0·0001) and reduction in mean birthweight of term, singleton infants (-55·3 g, 95% CI -109·3 to -1·4; p=0·0445). INTERPRETATION: Women had a 0·7-0·9% risk of influenza per month of pregnancy during the influenza season, and antenatal influenza was associated with increased risk for some adverse pregnancy outcomes. These findings support the added value of antenatal influenza vaccination to improve perinatal outcomes. FUNDING: US Centers for Disease Control and Prevention. TRANSLATIONS: For the Thai, Hindi, Marathi and Spanish translations of the abstract see Supplementary Materials section.
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Países en Desarrollo/estadística & datos numéricos , Recién Nacido Pequeño para la Edad Gestacional , Gripe Humana/epidemiología , Complicaciones Infecciosas del Embarazo/epidemiología , Resultado del Embarazo/epidemiología , Nacimiento Prematuro/epidemiología , Adulto , Estudios de Cohortes , Femenino , Humanos , Incidencia , India , Recién Nacido , Estudios Longitudinales , Masculino , Perú , Embarazo , Estudios Prospectivos , Tailandia , Adulto JovenRESUMEN
BACKGROUND: The World Health Organization (WHO) recommends case definitions for influenza surveillance that are also used in public health research, although their performance has not been assessed in many risk groups, including pregnant women in whom influenza may manifest differently. We evaluated the performance of symptom-based definitions to detect influenza in a cohort of pregnant women in India, Peru, and Thailand. METHODS: In 2017 and 2018, we contacted 11 277 pregnant women twice weekly during the influenza season to identify illnesses with new or worsened cough, runny nose, sore throat, difficulty breathing, or myalgia and collected data on other symptoms and nasal swabs for influenza real-time reverse transcription-polymerase chain reaction (rRT-PCR) testing. We calculated sensitivity, specificity, positive-predictive value, and negative-predictive value of each symptom predictor, WHO respiratory illness case definitions, and a de novo definition derived from results of multivariable modeling. RESULTS: Of 5444 eligible illness episodes among 3965 participants, 310 (6%) were positive for influenza. In a multivariable model, measured fever ≥38°C (adjusted odds ratio [95% confidence interval], 4.6 [3.1-6.8]), myalgia (3.0 [2.2-4.0]), cough (2.7 [1.9-3.9]), and chills (1.6 [1.1-2.4]) were independently associated with influenza illness. A definition based on these 4 (measured fever, cough, chills, or myalgia) was 95% sensitive and 27% specific. The WHO influenza-like illness (ILI) definition was 16% sensitive and 98% specific. CONCLUSIONS: The current WHO ILI case definition was highly specific but had low sensitivity. The intended use of case definitions should be considered when evaluating the tradeoff between sensitivity and specificity.
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Gripe Humana , Orthomyxoviridae , Complicaciones Infecciosas del Embarazo , Países en Desarrollo , Femenino , Humanos , Gripe Humana/diagnóstico , Gripe Humana/epidemiología , Embarazo , Complicaciones Infecciosas del Embarazo/diagnóstico , Complicaciones Infecciosas del Embarazo/epidemiología , Mujeres EmbarazadasRESUMEN
For many years, track-average linear energy transfer (LET), [Formula: see text] has been used to quantify the radiation-induced phenomena in biological and physical systems. However, due to the need for including into the radiotherapy treatment planning system, parameters that are clinical and biologically relevant, a precise knowledge of the dose-average LET, [Formula: see text] becomes essential. Besides, several dosimetric studies have revealed that [Formula: see text] is fundamental to describe the dosimeter's response induced by photons. The most important data sets publicly available for [Formula: see text] of electron generated by photons are those reported for measurements performed in methane-based tissue-equivalent gas. However, comparing to liquid water, the electron spectra generated by low photon energy might not be similar due to the photoelectric effect. Thus, this work aimed at investigating the [Formula: see text] of electron spectra generated in liquid water and LiF:Mg,Ti by ten x-ray beams from 20 kV to 300 kV, 137Cs and 60Co gamma. The results suggest that [Formula: see text] is more sensitive to the surrounding environment than [Formula: see text] and consequently, it might be a more appropriate parameter to quantify the radiation effect and damage in matter induced by photons. Besides, good agreement (6% to 12% differences versus 10% to 15% uncertainties in the experiments) was observed between the data obtained in this work for liquid water and the experimental values published for methane-based tissue-equivalent gas at energies above 60 keV. Whereas at lowest energies, the minimum difference is around 18% which can be associated to the difference between the two media.
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Radioisótopos de Cesio , Radioisótopos de Cobalto , Transferencia Lineal de Energía , Radiometría/instrumentación , Electrones , Fluoruros , Rayos gamma , Gases , Compuestos de Litio , Método de Montecarlo , Fantasmas de Imagen , Fotones , Poliestirenos , Dosis de Radiación , Reproducibilidad de los Resultados , Titanio , Agua , Rayos XRESUMEN
Energy-dependence of Gafchromic films exposed to low-energy photons has been reported to be a function of absorbed-dose. However, these studies are based on a relative-response, R, which considers the absorbed-dose in water and not within the film sensitive-volume. This work investigated the relative-efficiency, REfilm, (ratio of absorbed-dose required to produce the same net optical density (netOD) by 60Co gamma and by x-ray) of Gafchromic EBT3 and MD-V3 films exposed to five x-ray beams from 20â¯kV to 160â¯kV and 60Co gamma rays. A factor that accounts for the energy-dependence, fx,Q,med, based on REfilm, phantom-material and depth at which the films are placed during irradiation was used to remove the influence of absorbed dose. Values of REfilm indicated that the absorbed dose from 60Co gamma rays needs to be 4 and 3 times larger than those from 20â¯kV x-rays to produce the same netOD within the EBT3 and MD-V3 sensitive volumes, respectively. Thus, saturation could help explain why Gafchromic films show under-response to very low doses from low-energy photon beams, regardless of film model. Furthermore, REfilm, was found to be nearly independent of netOD and colour-channels. Consequently, fx,Q,med is independent of the absorbed dose and colour-channels. In contrast, besides the variation with the photon energy, fx,Q,med varied with film model, depth and phantom material used during the irradiation. Thus, the results suggest that fx,Q,med is a more reliable wide-ranging parameter for evaluating the degree of energy-dependence of the film rather than the relative-response method commonly considered.
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Dosimetría por Película/instrumentación , Fotones , Radioisótopos de Cobalto , Método de Montecarlo , Fantasmas de Imagen , Rayos XRESUMEN
BACKGROUND: The World Health Organization identifies pregnant women as at high-risk for severe influenza, but influenza vaccines are underutilized among pregnant women. Data on influenza burden during pregnancy are largely limited to high-income countries and data on the impact of influenza on birth and perinatal outcomes are scarce. METHODS/DESIGN: This prospective, longitudinal cohort study of pregnant women in middle-income countries is designed to address three primary objectives: 1) to evaluate the effect of laboratory-confirmed influenza during pregnancy on pregnancy and perinatal outcomes; 2) to estimate the incidences of all-cause acute respiratory illness and laboratory-confirmed influenza during pregnancy; and 3) to examine the clinical spectrum of illness associated with influenza viruses. Through a multi-country network approach, three sites aim to enroll cohorts of 1500-3000 pregnant women just before local influenza seasons. Women aged ≥ 18 years with expected delivery dates ≥ 8 weeks after the start of the influenza season are eligible. Women are followed throughout pregnancy through twice weekly surveillance for influenza symptoms (≥ 1 of myalgia, cough, runny nose, sore throat, or difficulty breathing) and have mid-turbinate nasal swabs collected for influenza virus testing during illness episodes. Primary outcomes include relative risk of preterm birth and mean birth weight among term singleton infants of women with and without reverse transcription polymerase chain reaction-confirmed influenza during pregnancy. Gestational age is determined by ultrasound at < 28 weeks gestation and birth weight is measured by digital scales using standardized methods. Sites are primarily urban in Bangkok, Thailand; Lima, Peru; and Nagpur, India. All sites recruit from antenatal clinics at referral hospitals and conduct surveillance using telephone calls, messaging applications, or home visits. Nasal swabs are self-collected by participants in Thailand and by study staff in Peru and India. During the first year (2017), sites enrolled participants during March-May in Peru and May-July in India and Thailand; 4779 women were enrolled. DISCUSSION: This study aims to generate evidence of the impact of influenza during pregnancy to inform decisions by Ministries of Health, healthcare providers, and pregnant women in middle-income countries about the value of influenza vaccination during pregnancy.
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Gripe Humana/epidemiología , Complicaciones Infecciosas del Embarazo/epidemiología , Resultado del Embarazo/epidemiología , Nacimiento Prematuro/epidemiología , Adolescente , Adulto , Niño , Femenino , Humanos , Incidencia , India/epidemiología , Lactante , Recién Nacido , Gripe Humana/diagnóstico , Estudios Longitudinales , Perú/epidemiología , Embarazo , Complicaciones Infecciosas del Embarazo/diagnóstico , Estudios Prospectivos , Tailandia/epidemiologíaRESUMEN
La esquizofrenia y cuadros psicóticos relacionados son trastornos complejos que generalmente emergen en el período de transición de la adolescencia hacia la adultez, por lo que sus consecuencias pueden ser deletéreas y producir un alto número de años de vida perdidos por discapacidad. Un importante factor pronóstico es el tiempo transcurrido entre el inicio de la enfermedad y el inicio del tratamiento farmacológico, por lo que la detección temprana de la enfermedad es factor imprescindible. En esta revisión se examinan aspectos históricos, neurobiológicos y concepciones acerca de los estadios clínicos de alto riesgo para el desarrollo de esquizofrenia. En el ámbito de predicción clínica se presentan el modelo de los "síntomas básicos" de Huber y Gross, y el modelo de "criterios de riesgo ultra alto para esquizofrenia" de Mc Gorry y colaboradores. Se revisan los debates y resultados de abordajes tanto farmacológicos como psicoterapéuticos y se subraya claramente la necesidad de utilizar protocolos de detección de las fases preclínicas de esquizofrenia y otras psicosis en nuestro país.
Schizophrenia and related psychotic conditions are complex disorders that generally emerge during the transition from adolescence to adulthood, so that their consequences may be deleterious and produce a high number of years of life lost due to disability. An important prognostic factor is the time elapsed between the onset of the disease and the beginning of pharmacological treatment, reason for which the early detection of the disease is an essential factor. This review examines historical aspects, neurobiological findings and conceptions about the high risk clinical stages for the development of schizophrenia. . In the field of clinical prediction, Huber and Gross' "basic symptoms" model, and Mc Gorry et al's "ultrahigh risk criteria for schizophrenia" model are presented. Debates about and results of both pharmacological and psychotherapeutic approaches are examined and the need to utilize detection protocols of the preclinical phases of schizophrenia and other psychoses in our country is strongly emphasized.
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Electrons generated in matter by photons could be a fundamental basis for an adequate analysis of radiation effects and damage. We have studied separately the 'primary electrons' generated directly by photons from the 'secondary electrons' (SE) produced by electron-electron interactions. In this work, track-average linear energy transfer, [Formula: see text], of SE in LiF:Mg,Ti and liquid water produced by twelve photon energy beams from 20 kV x-ray to 60Co gamma rays have been investigated using the EGSnrc Monte Carlo Code. The exposure of LiF:Mg,Ti in different phantom materials has been considered. Depending on the photon energy, SE represent 40%-90% of the total electron fluence (TEF) between 1 keV and 10 keV, being higher when the photon energy increases. Independent of the medium, [Formula: see text] versus mean photon energy displays a local minimum at around 40 keV, followed by a local maximum at ~80 keV-100 keV. The [Formula: see text] of SE generated by the x-ray beams are of order of 11 keV µm-1 to 19 keV µm-1 in LiF:Mg,Ti and 5 keV µm-1 to 9 keV µm-1 in liquid water which represent 3-5 times those produced by 60Co gamma rays in both media. These values were considerably greater than those of TEF, by factors of 3-8. Furthermore, [Formula: see text] of SE generated in liquid water by 20 kV-200 kV x-rays are similar to those of 76 MeV-120 MeV 3He ions. Contrary to the TEF, where [Formula: see text] were independent of the phantom material, at low photon energies [Formula: see text] of SE was found to be sensitive to the surrounding medium showing higher values within the phantom than in air. This result, which agrees with published experimental results, implies the importance of the SE ionization density for an understanding of dosimeter response induced by photon beams.
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Electrones , Transferencia Lineal de Energía , Fantasmas de Imagen , Monitoreo de Radiación/instrumentación , Agua/química , Radioisótopos de Cesio/química , Radioisótopos de Cobalto/química , Fluoruros/química , Rayos gamma , Humanos , Compuestos de Litio/química , Magnesio/química , Método de Montecarlo , Titanio/química , Rayos XRESUMEN
Due to the great global concern regarding bacterial resistance to antibiotics, an ongoing search for new molecules having antibacterial activity is necessary. This study evaluated the antibacterial and anticandidal effects of a hexane extract from the root of Salvia apiana. Salvia extracts at concentrations of 27, 13.5, 6.8 and 3.4mg/ml caused growth inhibition of Staphylococcus aureus, Streptococcus pyogenes, Enterococcus faecalis and Candida albicans. However, no significant effect was observed on Escherichia coli and Candida tropicalis in comparison to vehicle. It was here demonstrated for the first time that Salvia apiana has an important antimicrobial effect on human pathogens of great clinical value, thus opening the field to continue the evaluation of this lamiaceous plant for its future use as a therapeutic agent.
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Antibacterianos/farmacología , Antifúngicos/farmacología , Candida/efectos de los fármacos , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Salvia/química , Antibacterianos/aislamiento & purificación , Antifúngicos/aislamiento & purificación , Pruebas Antimicrobianas de Difusión por Disco , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Hexanos , Extractos Vegetales/aislamiento & purificación , Extractos Vegetales/farmacología , Raíces de Plantas/química , Solventes , Especificidad de la EspecieRESUMEN
Debido a la gran problemática mundial de la resistencia bacteriana a los antibióticos, es necesaria la búsqueda continua de nuevas moléculas con características antimicrobianas. Este estudio evaluó el efecto antibacteriano y antifúngico de un extracto hexánico proveniente de la raíz de Salvia apiana. Los extractos de salvia a las concentraciones de 27; 13,5; 6,8 y 3,4mg/ml causaron inhibición del crecimiento de Staphylococcus aureus, Streptococcus pyogenes, Enterococcus faecalis y Candida albicans. Sin embargo, no presentaron efecto significativo sobre Escherichia coli y Candida tropicalis al compararse con los valores del vehículo en las valoraciones de difusión en pozo. Se demostró que S. apiana tiene un efecto antimicrobiano significativo sobre patógenos de gran importancia clínica, lo que abre el campo para continuar evaluando a esta lamiácea en vistas a su posible empleo en el futuro como un agente terapéutico
Due to the great global concern regarding bacterial resistance to antibiotics, an ongoing search for new molecules having antibacterial activity is necessary. This study evaluated the antibacterial and anticandidal effects of a hexane extract from the root of Salvia apiana. Salvia extracts at concentrations of 27, 13.5, 6.8 and 3.4mg/ml caused growth inhibition of Staphylococcus aureus, Streptococcus pyogenes, Enterococcus faecalis and Candida albicans. However, no significant effect was observed on Escherichia coli and Candida tropicalis in comparison to vehicle. It was here demonstrated for the first time that Salvia apiana has an important antimicrobial effect on human pathogens of great clinical value, thus opening the field to continue the evaluation of this lamiaceous plant for its future use as a therapeutic agent
Asunto(s)
Extractos Vegetales/análisis , Extractos Vegetales/uso terapéutico , Productos con Acción Antimicrobiana , Descubrimiento de Drogas , Antibacterianos/análisis , Antifúngicos/análisis , Staphylococcus aureus/efectos de los fármacos , Streptococcus pyogenes/efectos de los fármacos , Candida albicans/efectos de los fármacos , Enterococcus faecalis/efectos de los fármacosRESUMEN
Purpose: To examine the historical process for institutionalization of therapeutic abortion in Peru and to explain its current condition. Methodology: Review of bibliographic information available in the country regarding the process conducted by many institutions to have the Ministry of Health approve the National Guide for Therapeutic Abortion. Subsequently, the lead researcher met with 10 heads of the Gynecology and Obstetrics Service/Department from the same number of hospitals, from whom he requested information, as they have been regulating the provision of therapeutic abortion services by means of local Guides or Protocols for the last 5 years. Results: The formalization of the National Guide for the provision of therapeutic abortion services by the Ministry of Health has been a persistent endeavor of many institutions of civil society, but the 10 convened hospitals have already been responding to the demand for the past 5 years. In these 5 years, 257 therapeutic abortions were performed. The frequency of therapeutic abortions is still low; however, there is a progressive increase over the years. The frequency of therapeutic abortions is predominant in the second trimester of pregnancy, with congenital anomalies incompatible with life being the most frequent cause. Misoprostol to evacuate the uterus has been used in 95% of the cases, and only 2% minor complications have been verified.
Objetivo: Examinar el proceso histórico para institucionalizar el aborto terapéutico en el Perú y precisar su situación actual. Metodología: Revisión de la información bibliográfica existente en el país en relación al proceso seguido por muchas instituciones hasta conseguir que el Ministerio de Salud apruebe la Guía Nacional para el Aborto Terapéutico. Luego el investigador principal convocó a 10 jefes de servicio/departamento de Ginecología y Obstetricia de igual número de hospitales que tienen regulada la prestación de servicios de aborto terapéutico mediante Guías o Protocolos locales desde 5 años antes, a quienes se les solicitó información. Resultados: La oficialización de la Guía Nacional para la prestación de servicios de aborto terapéutico por parte del Ministerio de Salud ha sido un trabajo persistente de muchas instituciones de la sociedad civil, pero los 10 hospitales convocados ya venían respondiendo a la demanda desde 5 años atrás. En los 5 años se atendió 257 abortos terapéuticos. La frecuencia del aborto terapéutico es aún baja, sin embargo se aprecia un aumento progresivo conforme avanzan los años. Es predominante la frecuencia de abortos terapéuticos en el segundo trimestre del embarazo, siendo la causa más frecuente las anomalías congénitas incompatibles con la vida. El uso del misoprostol en la evacuación del útero ha alcanzado el 95% de los casos y no se ha verificado más de 2% de complicaciones leves. Conclusión: El aborto legal por causales de salud se viene ofertando en forma restringida en el Perú.
RESUMEN
LiF:Mg,Ti, are widely used to estimate absorbed-dose received by patients during diagnostic or medical treatment. Conveniently, measurements are usually made in plastic phantoms. However, experimental conditions vary from one group to another and consequently, a lack of consensus data exists for the energy dependence of thermoluminescent (TL) response. This work investigated the energy dependence of TLD-100 TL-response and the effect of irradiating the dosimeters in different phantom materials for a broad range of energy photons in an attempt to understand the parameters that affect the discrepancies reported by various research groups. TLD-100s were exposed to 20-300 kV narrow x-ray spectra, (137)Cs and (60)Co photons. Measurements were performed in air, PMMA, wt1, polystyrene and TLDS as surrounding material. Total air-kerma values delivered were between 50 and 150 mGy for x-rays and 50 mGy for (137)Cs and (60)Co beams; each dosimeter was irradiated individually. Relative response, R, defined as the TL-response per air-kerma and relative efficiency, RE, described as the TL-response per absorbed-dose (obtained through Monte Carlo (MC) and analytically) were used to describe the TL-response. Both R and RE are normalized to the responses in a (60)Co beam. The results indicate that the use of different phantom materials affects the TL-response and this response varies with energy and material type. MC simulations reproduced qualitatively the experimental data: a) R increases, reaches a maximum at ~25 keV and decreases; b) RE decreases, down to a minimum at ~60 keV, increases to a maximum at ~150 keV and after decreases. Independent of the phantom materials, RE strongly depends on how the absorbed dose is evaluated and the discrepancies between RE evaluated analytically and by MC simulation are around 4% and 18%, dependent on the photon energy. The comparison between our results and that reported in the literature suggests that the discrepancy observed between different research groups appears to be most likely related to supralinearity effect, phantom materials, difference on the energy-spectra and geometry conditions during each experiment rather than parameters such as heating-rate or annealing procedure, which was supported by MC simulation. From the results obtained in this work and the strict analysis performed, we can conclude that for clinical applications of TLD-100, special attention must be taken when published data are used to convert TL calibration curve from (60)Co to low-energy photons. Otherwise, this can lead to incorrect results when later used to measure absorbed dose in human tissue.
Asunto(s)
Fantasmas de Imagen , Fotones , Dosimetría Termoluminiscente/normas , Calibración , Humanos , Dosimetría Termoluminiscente/instrumentación , Dosimetría Termoluminiscente/métodos , Rayos XRESUMEN
Antecedentes: La preeclampsia (PE) es la primera causa de muerte materna en el mundo y afecta alrededor de 10 por ciento de las gestantes en algunas regiones del Perú. Se ha determinado varios genes involucrados en el riesgo de PE, entre ellos el gen del factor de crecimiento endotelial vascular (VEGF). Objetivos: Estudiar el polimorfismo +936 CT en el gen VEGF y evaluar su asociación con la preeclampsia. Diseño: Estudio observacional, relacional (asociativo), tipo casos-control (no experimental). Institución: Facultad de Medicina, Universidad Nacional Mayor de San Marcos. Participantes: Gestantes con y sin preeclampsia. Métodos: La muestra estuvo conformada por 94 gestantes (45 con PE y 49 controles sin PE) atendidas en el hospital Docente Madre-Niño San Bartolomé. Previo consentimiento informado, se colectó de 3 a 5 mL de sangre de vena antecubital. El ADN fue aislado aplicando métodos estándares. Se evaluó el polimorfismo VEGF mediante técnica PCR-RFLP y electroforesis en geles de agarosa o poliacrilamida. Principales medidas de resultados: Asociación entre los genotipos y alelos VEGF con la preeclampsia. Resultados: Las distribuciones de los genotipos (CC, CT y TT) en el grupo de Casos se encontraron en ædesequilibrio de Hardy-WeinbergÆ (existió un factor que estuvo influenciando esa distribución), mientras que los genotipos en el grupo de Controles se encontraron en equilibrio. Las frecuencias de los genotipos VEGF en los casos y controles mostraron diferencias no significativas, aunque en el límite de significancia (X2=5,630, p=0,060). El genotipo homocigoto TT fue más frecuente en los casos y los genotipos heterocigotos CT fueron más frecuentes en los controles. Las diferencias en las frecuencias de alelos C y T en los casos y controles no fueron significativas (X2=0,614, p=0,434). Conclusiones: Preliminarmente, se concluye que no existió asociación entre los genotipos (aunque en el límite de significancia) y alelos VEGF con la preeclampsia, en la...
Background: Preeclampsia (PE) is the first cause of maternal death in the world and affects about 10 per cent of pregnant women in some Peruvian regions. Various genes are involved en PE risk, including the vascular endothelial gene factor (VEGF). Objetives: To study VEGF gene +936 CT polymorphism and to determine its association with preeclampsia. Design: Observational, relational (associative), case-control (non-experimental) study. Setting: Faculty of Medicine, Universidad Nacional Mayor de San Marcos, Lima, Peru. Participants: Pregnant women with and without preeclampsia. Methods: The sample included 94 pregnant women (45 with PE and 49 controls without PE) attended at Hospital Docente Madre-Niño San Bartolome. Following informed consent, 3-5 mL of blood was collected. DNA was isolated by standard methods. VEGF polymorphism was determined by PCR-RFLP and electrophoresis in either agarose or polyacrylamide gels. Main outcome measures: Association between VEGF genotypes and alleles and preeclampsia. Results: CC, CT y TT genotypes distribution in the Cases group were in æHardy-Weinberg imbalanceÆ (there was a factor influencing that distribution), while genotypes in the Control group were in equilibrium. Cases and controls VEGF genotypes frequencies showed non-significant differences within significance limits (X2=5.630, p=0.060). TT homocygote was the most frequent genotype present in cases and CT heterocygote genotypes the most frequents in controls. C and T alleles frequency differences in cases and controls were not significant (X2=0.614, p=0.434). Conclusions: There was no association between VEGF genotypes (but in significance limit) and alleles and preeclampsia in the sample studied. Results have to be confirmed and studies in other Peruvian subjects are necessary...
Asunto(s)
Humanos , Adulto , Femenino , Embarazo , Adulto Joven , Persona de Mediana Edad , Factor A de Crecimiento Endotelial Vascular , Genotipo , Polimorfismo Genético , Preeclampsia , Estudios Observacionales como Asunto , Estudios de Casos y ControlesRESUMEN
Antecedentes: Los procesos fisiopatológicos que ocurren a nivel celular y molecular en la restricción de crecimiento intrauterino (RCIU) son aún desconocidos. La catecol-O-metiltransferasa (COMT) es una enzima de fase II que inactiva los catecol estrógenos al transferir un grupo metílico. Se conoce un polimorfismo funcional Val158 Met en el gen COMT como un marcador susceptible para diversas enfermedades maternoperinatales, existiendo estudios que sugieren que el alelo que codifica una COMT de baja actividad puede ser un marcador susceptible para RCIU. Por lo tanto, el estudio del polimorfismo COMT ofrece una nueva estrategia para la evaluación de marcadores genéticos que pueden ser utilizados para la detección de ciertas alteraciones asociadas al embarazo. Objetivos: Establecer la asociación entre el polimorfismo Val158Met catecol-O-metiltransferasa (COMT) y la restricción de crecimiento intrauterino. Institución: Facultad de Medicina, Universidad Nacional Mayor de San Marcos, Lima, Perú. Diseño: Estudio tipo relacional (asociativo), con diseño observacional, tipo caso-control (no experimental). Materiales: Muestra de sangre materna de parturientas. Métodos: Durante el año 2011, se obtuvo 81 muestras para genotipaje del gen COMT. De ellas, 26 (32,1%) correspondieron a parturientas con RCIU (casos) y 55 (67,9%) a muestras de madres de hijos sin RCIU (controles). La distribución de los genotipos fue evaluada usando la prueba de chi cuadrado. Se comprobó la distribución proporcional de los genotipos en los grupos con RCIU y sin RCIU con la hipótesis nula de Hardy-Weinberg. Las madres participantes firmaron un consentimiento informado. Principales medidas de resultados: Asociación entre los genotipos COMT y la RCIU, y entre los alelos COMT Val/Met y la RCIU. Resultados: Las distribuciones de los genotipos en los grupos con RCIU y sin RCIU estuvieron de acuerdo a la hipótesis nula de Hardy-Weinberg. Al relacionar los genotipos COMT Val/Met con la condición de RCIU, la prueba X²=1.8057, gl=2, p=0.4054, no encontró asociación entre dichos genotipos y la RCIU. Al determinar la asociación entre los alelos COMT y la RCIU, tampoco se encontró asociación entre los alelos COMT Val/Met y la condición de RCIU en la muestra estudiada, con prueba X²=0.3659, gl=1, p=0.5453. Conclusiones: No se encontró asociación entre los genotipos COMT y la RCIU, ni entre los alelos COMT Val/Met y la RCIU, en la muestra estudiada.
Background: Cellular and molecular events in the pathophysiology of intrauterine growth restriction (IUGR) are still unknown. Cathecol O-methyltransferase (COMT) is a phase II enzyme that inactivates cathecol estrogens by transferring a methyl group. A functional polymorphism Val158 Met in COMT gene is known as susceptible marker for diverse maternal and perinatal diseases, and studies suggest the allele codifying a low activity COMT may be a susceptible marker for IUGR. COMT polymorphism study may be a new strategy to determine genetic markers that might be used for detection of certain disorders related to pregnancy. Objectives: To determine association of Val158Met cathecol-O-methyltransferase (COMT) polymorphism and intrauterine growth restriction. Setting: Faculty of Medicine, Universidad Nacional Mayor de San Marcos, Lima, Peru. Design: Relational (associative), observational, case-control (non-experimental) study. Materials: Maternal blood samples obtained following delivery. Methods: During 2011, 81 blood samples were obtained from post partum mothers for COMT gene genotyping, 26 (32.1%) were mothers with IUGR (cases) and 55 (67.9%) without IUGR (controls). Genotype distribution was determined by chi square test. Genotypes proportional distribution in IUGR and non-IUGR groups was determined with Hardy-Weinbergs null hypothesis. All women signed informed consent. Main outcome measures: Association of COMT genotypes and IUGR, and between COMT Val/Met alleles and IUGR. Results: Genotype distribution in IUGR and non-IUGR groups agreed with Hardy-Weinberg null hypothesis. There was no association of COMT Val/Met genotypes and IUGR, X²=1.8057, gl=2, p=0.4054. There was no association between COMT Val/Met alleles and IUGR, X²=0.3659, gl=1, p=0.5453. Conclusions: No association was found either between COMT genotypes and IUGR or between COMT Val/Met alleles and IUGR.