Low-dose radiotherapy to the lungs using an interventional radiology C-arm fluoroscope: Monte Carlo treatment planning and dose measurements in a postmortem subject.

Objective.The goal of this study was to use Monte Carlo (MC) simulations and measurements to investigate the dosimetric suitability of an interventional radiology (IR) c-arm fluoroscope to deliver low-dose radiotherapy to the lungs.Approach.A previously-validated MC model of an IR fluoroscope was used to calculate the dose distributions in a COVID-19-infected patient, 20 non-infected patients of varying sizes, and a postmortem subject. Dose distributions for PA, AP/PA, 3-field and 4-field treatments irradiating 95% of the lungs to a 0.5 Gy dose were calculated. An algorithm was created to calculate skin entrance dose as a function of patient thickness for treatment planning purposes. Treatments were experimentally validated in a postmortem subject by using implanted dosimeters to capture organ doses.Main results.Mean doses to the left/right lungs for the COVID-19 CT data were 1.2/1.3 Gy, 0.8/0.9 Gy, 0.8/0.8 Gy and 0.6/0.6 Gy for the PA, AP/PA, 3-field, and 4-field configurations, respectively. Skin dose toxicity was the highest probability for the PA and lowest for the 4-field configuration. Dose to the heart slightly exceeded the ICRP tolerance; all other organ doses were below published tolerances. The AP/PA configuration provided the best fit for entrance skin dose as a function of patient thickness (R2 = 0.8). The average dose difference between simulation and measurement in the postmortem subject was 5%.Significance.An IR fluoroscope should be capable of delivering low-dose radiotherapy to the lungs with tolerable collateral dose to nearby organs.

Monte Carlo simulations and phantom validation of low-dose radiotherapy to the lungs using an interventional radiology C-arm fluoroscope.

PURPOSE: To use MC simulations and phantom measurements to investigate the dosimetry of a kilovoltage x-ray beam from an IR fluoroscope to deliver low-dose (0.3-1.0 Gy) radiotherapy to the lungs. MATERIALS AND METHODS: PENELOPE was used to model a 125 kV, 5.94 mm Al HVL x-ray beam produced by a fluoroscope. The model was validated through depth-dose, in-plane/cross-plane profiles and absorbed dose at 2.5-, 5.1-, 10.2- and 15.2-cm depths against the measured beam in an acrylic phantom. CT images of an anthropomorphic phantom thorax/lungs were used to simulate 0.5 Gy dose distributions for PA, AP/PA, 3-field and 4-field treatments. DVHs were generated to assess the dose to the lungs and nearby organs. Gafchromic film was used to measure doses in the phantom exposed to PA and 4-field treatments, and compared to the MC simulations. RESULTS: Depth-dose and profile results were within 3.2% and 7.8% of the MC data uncertainty, respectively, while dose gamma analysis ranged from 0.7 to 1.0. Mean dose to the lungs were 1.1-, 0.8-, 0.9-, and 0.8- Gy for the PA, AP/PA, 3-field, and 4-field after isodose normalization to cover âˆ¼ 95% of each lung volume. Skin dose toxicity was highest for the PA and lowest for the 4-field, and both arrangements successfully delivered the treatment on the phantom. However, the dose distribution for the PA was highly non-uniform and produced skin doses up to 4 Gy. The dose distribution for the 4-field produced a uniform 0.6 Gy dose throughout the lungs, with a maximum dose of 0.73 Gy. The average percent difference between experimental and Monte Carlo values were -0.1% (range -3% to +4%) for the PA treatment and 0.3% (range -10.3% to +15.2%) for the 4-field treatment. CONCLUSION: A 125 kV x-ray beam from an IR fluoroscope delivered through two or more fields can deliver an effective low-dose radiotherapy treatment to the lungs. The 4-field arrangement not only provides an effective treatment, but also significant dose sparing to healthy organs, including skin, compared to the PA treatment. Use of fluoroscopy appears to be a viable alternative to megavoltage radiation therapy equipment for delivering low-dose radiotherapy to the lungs.

Tendencia de la mortalidad por fibrosis quística en Chile, 1997-2017 / Cystic fibrosis mortality trend in chile, 1997-2017

Introducción. La Fibrosis Quística es la enfermedad hereditaria con pronóstico reducido más frecuente en raza blanca. Su incidencia varía según etnias. En Chile, la incidencia estimada es de 1/10.000 habitantes y la evidencia nacional acerca de la magnitud y caracterización de defunciones es escasa. El objetivo de este estudio es determinar la evolución de mortalidad por fibrosis quística en Chile durante 1997-2017. Materiales y Métodos. Estudio descriptivo retrospectivo sobre la tendencia de mortalidad por fibrosis quística en Chile. A partir de bases de datos secundarias del sistema de estadísticas de mortalidad del país, se analizó la cohorte de fallecidos registrado en el certificado de defunción como fibrosis quística. Se calcularon tasas de mortalidad crudas y ajustadas para todos los años observados. Se realizó un análisis para las defunciones en menores 40 años; según las variables sexo, edad y región. Se estimó el cambio porcentual anual utilizando el programa Joinpoint-Regression. Resultados. Se registraron 198 defunciones (49% mujeres). La edad media y mediana de defunción aumentaron progresivamente, desde 1997-2001 con media 8,5 y mediana 6 años a 2013-2017 con media 19,6 y mediana 20 años (p-valor<0,05). La tasa de mortalidad en los menores de 1 año presentó una tendencia decreciente con un cambio porcentual anual de - 32,5%, estadísticamente significativo. La región de Atacama presentó un riesgo de muerte 6,12 veces mayor que el promedio del país. Discusión. En Chile, la edad de defunción por fibrosis quística ha aumentado progresivamente y la mortalidad en los <1 año ha disminuido a lo largo de los últimos años.

Introduction. Cystic Fibrosis is the most frequent hereditary disease in whites, with a reduced prognosis. Its incidence varies by ethnicity. In Chile, the estimated incidence is 1/10,000 inha-bitants and national evidence regarding the magnitude and characterization of deaths is scarce.The aim of this study es to describe the evolution of cystic fibrosis mortality in Chile during 1997-2017. Materials and Methods. Retrospective descriptive study on the mortality trend due to cystic fibrosis in Chile. From secondary databases of the country's mortality statistics system, the cohort of deceased due to cystic fibrosis, as registered in the death certificate was analyzed. Crude and adjusted mortality rates were calculated for all observed years. An analysis was performed for deaths in persons younger 40 years; according to the variables of sex, age and region. The annual percentage change was estimated using the Joinpoint-Regression program.Results. 198 deaths were registered (49% women). For those younger than 40 years at the time of death, the mean and median age of death increased progressively, from mean 8.5 and median 6 years in 1997 to 2001 to a mean of 19.6 and median of 20 years in 2013-2017 (p-value <0.05). The mortality rate in under 1 year of ages presented a decreasing trend with an annual percentage change of -32.5%. The Atacama region presented a risk of death 6.12 times higher than the country's average.Discussion. In Chile, the age of death due to cystic fibrosis has progressively increased and mortality in <1 year has decreased in recent years

Genetic (co)variation in skin pigmentation patterns and growth in rainbow trout.

From a physiological-behavioral perspective, it has been shown that fish with a higher density of black eumelanin spots are more dominant, less sensitive to stress, have higher feed intake, better feed efficiency and therefore are larger in size. Thus, we hypothesized that genetic (co)variation between skin pigmentation patterns and growth exists and it is advantageous in rainbow trout. The objective of this study was to determine the genetic relationships between skin pigmentation patterns and BW in a breeding population of rainbow trout. We performed a genetic analysis of pigmentation traits including dorsal color (DC), lateral band (LB) intensity, amount of spotting above (SA) and below (SB) the lateral line, and BW at harvest (HW). Variance components were estimated using a multi-trait linear animal model fitted by restricted maximum likelihood. Estimated heritabilities were 0.08±0.02, 0.17±0.03, 0.44±0.04, 0.17±0.04 and 0.23±0.04 for DC, LB, SA, SB and HW, respectively. Genetic correlations between HW and skin color traits were 0.42±0.13, 0.32±0.14 and 0.25±0.11 for LB, SA and SB, respectively. These results indicate positive, but low to moderate genetic relationships between the amount of spotting and BW in rainbow trout. Thus, higher levels of spotting are genetically associated with better growth performance in this population.

Genomewide single nucleotide polymorphism discovery in Atlantic salmon (Salmo salar): validation in wild and farmed American and European populations.

A considerable number of single nucleotide polymorphisms (SNPs) are required to elucidate genotype-phenotype associations and determine the molecular basis of important traits. In this work, we carried out de novo SNP discovery accounting for both genome duplication and genetic variation from American and European salmon populations. A total of 9 736 473 nonredundant SNPs were identified across a set of 20 fish by whole-genome sequencing. After applying six bioinformatic filtering steps, 200 K SNPs were selected to develop an Affymetrix Axiom(®) myDesign Custom Array. This array was used to genotype 480 fish representing wild and farmed salmon from Europe, North America and Chile. A total of 159 099 (79.6%) SNPs were validated as high quality based on clustering properties. A total of 151 509 validated SNPs showed a unique position in the genome. When comparing these SNPs against 238 572 markers currently available in two other Atlantic salmon arrays, only 4.6% of the SNP overlapped with the panel developed in this study. This novel high-density SNP panel will be very useful for the dissection of economically and ecologically relevant traits, enhancing breeding programmes through genomic selection as well as supporting genetic studies in both wild and farmed populations of Atlantic salmon using high-resolution genomewide information.

Efecto de los antagonistas de aldosterona en nefropatía diabética: revisión sistemática de la literatura / Systematic review of the effect of aldosterone antagonists on urinary albumin excretion in diabetic nephropathy

The beneficial effect angiotensin converting enzyme inhibitors (ACEI) and angiotensin II receptor antagonists (ARA) for diabetic nephropathy can be hampered by the phenomenon of aldosterone escape. Aldosterone antagonists such as espironolactone or epleronone could potentiate the effects of ACEI and ARA and avoid the later problem. We performed a systematic search of the literature on the effects of aldosterone antagonists on diabetic nephropathy. We searched for clinical trials and follow up studies measuring the effects of aldosterone antagonists on urinary albumin excretion among patients with diabetic nephropathy. We retrieved 1345 papers on the subject and 10 were selected for analysis. Among these, spironolactone was more effective than comparing drugs to achieve a reduction in urinary albumin excretion of approximately 30 to 40 percent. On the other hand epleronone was not superior to comparing drugs. All studies reported a modest reduction in glomerular filtration rate and an increase in serum potassium levels. In conclusion, spironolactone in doses of 25 to 100 mg/day reduces urinary albumin excretion but reduces also glomerular filtration rate and increases serum potassium levels.

Prone Position Ventilation Used during a Transfer as a Bridge to Ecmo Therapy in Hantavirus-Induced Severe Cardiopulmonary Syndrome.

Background. Transport of critically ill patients is a complex issue. We present a case using prone positioning as a bridge to extracorporeal membrane oxygenation (ECMO), performed by a critical retrieval team from a university hospital. Case Report. A 28-year-old male developed fever, progressive respiratory failure, and shock. He was admitted to ICU from a public hospital, and mechanical ventilation was begun, but clinical response was not adequate. ECMO was deemed necessary due to severe respiratory failure and severe shock. A critical retrieval team of our center was assembled to attempt transfer. Prone positioning was employed to stabilize and transfer the patient, after risk-benefit assessment. Once in our hospital, ECMO was useful to resolve shock and pulmonary edema secondary to Hantavirus cardiopulmonary syndrome. Finally, he was discharged with normal functioning. Conclusion. This case exemplifies the relevance of a retrieval team and bridge therapy. Prone positioning improves oxygenation and is safe to perform as transport if performed by a trained team as in this case. Preparation and organization is necessary to improve outcomes, using teams and organized networks. Catastrophic respiratory failure and shock should not be contraindications to transferring patients, but it must be done with an experienced team.

Percepción de mujeres consultantes de atención primaria sobre el abandono del tratamiento de depresión / Perception of female patients in a primary care service regarding quitting the treatment of depression

El tratamiento oportuno de los trastornos depresivos es considerado una prioridad sanitaria. Un obstáculo en el logro de este propósito es la baja adherencia o el abandono del tratamiento que realizan algunos consultantes. El objetivo de esta investigación fue comprender la percepción de personas que desertaron de su tratamiento en atención primaria respecto de los factores que motivaron ese abandono. Investigación de orientación cualitativa. Las participantes fueron mujeres entre 18 y 65 años, diagnosticadas de depresión, que ingresaron y abandonaron el Programa Nacional de Diagnóstico y Tratamiento de Depresión en el primer semestre del año 2008 y año 2009 en dos centros de salud familiar de la Octava Región, Chile. Se realizaron 15 entrevistas en profundidad semiestructuradas. las que fueron codifcadas y analizadas a través del método de comparación constante. Las principales razones de abandono del tratamiento se concentraron en la existencia de obstáculos en el acceso o continuidad de la atención y en aspectos relacionados con una percepción negativa del tratamiento recibido, especialmente del farmacológico, pero también del psicológico. Se observó en las consultantes que su implicación en el tratamiento era baja debido a desconocimiento del diagnóstico recibido o una discordancia entre el tratamiento recibido respecto a sus expectativas y creencias. Estos resultados indican que los profesionales de la enfermería podrían tener un rol clave en favorecer la permanencia de los consultantes en el tratamiento al poner una mayor consideración de las expectativas, creencias y necesidades de los propios consultantes.

Early treatment of depressive disorders is considered a health priority. One obstacle in achieving this purpose is the low adherence or abandonment of treatment performed by some consultants. The aim of this research is to understand the perception of people who deserted their treatment in primary care settings on the factors that led to the abandonment. The research uses an inductive strategy and qualitative approach as methodological basis. Participants were women aged 18 to 65 years, diagnosed with depression, who entered and left the National Program for Diagnosis and Treatment of Depression in the first half of 2008 and 2009 in two family care centers at the 8th Region, Chile. A total of 15 in-depth interviews were conducted and thereafter analyzed using the constant comparison method. The reasons for the abandonment referred to obstacles in the access and lack of continuity in the treatment, as well as factors related to negative perception of the treatment not only the pharmacological but also the psychological one. It was observed that consultants´ involvement in treatment was low due to scarce knowledge of their diagnosis received or a discrepancy between the treatment received regarding their expectations and beliefs. These results indicate that nurses could play a key role in improving the adherence to the treatment by considering patients’ expectations, beliefs and needs.

An actin-myosin functional assay for analysis of smooth muscle (anti-microfilament) autoantibodies in human plasma.

The detection of serum autoantibodies to smooth muscle (SMA) on rodent gastric mucosa by indirect immunofluorescence (IIF) has long been an immunodiagnostic marker for autoimmune hepatitis type 1 (AIH-1). The reactive antigenic moieties are cytoskeletal proteins which include polymeric F-actin as judged by the staining of microfilaments of tissue by IIF. However, their specificity for actin in AIH-1 can be and usually is uncertain. Using an in vitro functional assay, we compared the effects of Fab fragments of immunoglobulin (IgG) prepared from SMA-positive plasma from two patients with the effects of Fabs from 10 healthy subjects. Fabs are incorporated into an assay where actin (the putative antigen) activates skeletal muscle heavy meromyosin (HMM) ATPase activity. The data from these functional assays provide new insights into the significance of anti-microfilament assays in the diagnosis, and perhaps also pathogenesis, of AIH-1.

Efecto de un taller vivencial de orientación humanista en la auto-actualización de adolescentes de nivel socioeconomico bajo / Life based-workshop effect, with an humanistic orientation, in low income teenagers self-actualization

Este trabajo tiene como objetivo determinar el efecto de un taller vivencial de orientación humanista en el nivel de auto-actualización de los adolescentes que cursan enseñanza media. Para ello se utiliza un diseño experimental clásico de pre-test y post-test con grupo control. La muestra es no probabilística y se toma en dos colegios de nivel socioeconómico bajo de la Octava Región, Chile, con alumnos que cursan tercero y cuarto de la enseñanza media cuyas edades fluctúan entre 17 y 19 años, a quienes se les realizará una medición con el instrumento Personal Orientation Inventory (P.O.I.) validado para la población chilena. De acuerdo a los resultados obtenidos, se demuestra que es posible aumentar el nivel de auto-actualización en los adolescentes que participaron en el taller vivencial, siendo estadísticamente significativo (p< 0.05) en 8 de 12 dimensiones que son autonomía, vivir existencial, sensibilidad organísmica, auto-aprecio, auto-aceptación, naturaleza constructiva del hombre, sinergia y capacidad de contacto íntimo, por lo que el taller vivencial de orientación humanista es una modalidad eficaz y recomendable para favorecer un desarrollo integral de los adolescentes.

Environmental dependence of inbreeding depression in cultured Coho salmon (Oncorhynchus kisutch): aggressiveness, dominance and intraspecific competition.

We evaluated the effects of inbreeding on traits related to territorial dominance and tested whether the magnitude of inbreeding depression (ID) was modified by social environment in Coho salmon. Evaluation of behaviour in paired contests between juvenile salmon with different inbreeding (low, LI=9.5%; medium, MI=29.6%), did not show significant differences between their capacities for establishing territorial dominance (mean aggressiveness score, LI=20.0+/-22; MI=16.7+/-23 or for feeding attempts, LI=18.3+/-12; MI=21.1+/-12). However, fish with low inbreeding (LI) showed almost twice the aggressive pursuit of fish with medium inbreeding (MI), and had a higher specific growth rate (SGR) in culture (SGR(MI)=1.83+/-0.58; SGR(LI)=2.20+/-0.67). Additionally, we found evidence that the magnitude of ID was modified by social environment: (1) Masking: In small groups of fish (N=20), large dominant fish of MI, cultivated with small subordinate fish of LI, showed the same SGR as dominant fish of LI cultivated with small subordinate fish of MI. (2) Magnifying: A significant effect of ID on juvenile survival was detected only in high-density competitive environments. Thus, the number of lethal equivalents was 2.70 at high-density, and only 0.24 in a low-density environment. Our results show that differences in size associated with territorial dominance may mask deleterious effects of inbreeding under certain conditions, and support the concept that intraspecific competition usually magnifies the deleterious effects of inbreeding.

A novel biosensor for mercuric ions based on motor proteins.

We explored the potential of contractile proteins, actin and myosin, as biosensors of solutions containing mercuric ions. We demonstrate that the reaction of HgCl2 with myosin rapidly inhibits actin-activated myosin ATPase activity. Mercuric ions inhibit the in vitro analog of contraction, namely the ATP-initiated superprecipitation of the reconstituted actomyosin complex. Hg reduces both the rate and extent of this reaction. Direct observation of the propulsive movement of actin filaments (10 nm in diameter and 1 microm long) in a motility assay driven by a proteolytic fragment of myosin (heavy meromyosin or HMM) is also inhibited by mercuric ions. Thus, we have demonstrated the biochemical, biophysical and nanotechnological basis of what may prove to be a useful nano-device.

Prevalencia de patología oftalmológica en la población escolar de un distrito andino rural - Ocongate - Q'osqo - Perú / Prevalence of eye diseases in school children from a rural Andean district - Ocongate - Q'osqo - Peru

Se realizó un estudio en 475 escolares de los colegios del distrito de Ocongate, del departamento de QÆosqo, para determinar la prevalencia de patología ocular. Se encontró una prevalencia global del 7.8%. El grupo de patologías más diagnosticadas fueron los vicios de refracción (59.46%), seguidos por los trastornos de la Conjuntiva (24.32%). El diagnóstico clínico más frecuente fue el Astigmatismo, que presentó una tasa de prevalencia de 3.2%, seguido por la miopía y la conjuntivitis fotoeléctrica con una tasa de 1.3%. Se estudiaron la edad y sexo de los escolares, resaltando la prevalencia en el femenino que fue de 8.8%, mientras que en el masculino presentó una prevalencia del 7.1%; para ambos sexos la patología más frecuente fue el astigmatismo. El grupo de edad más afectado en el sexo femenino fue el de 5 a 9 años, mientras que para el masculino fue el de los 10 a 14 años. Los autores consideran que la prevalencia encontrada es alta, y que es necesario desarrollar mayor cantidad de estudios descriptivos sobre patología ocular y además implementar programas de Salud Visual para preservar uno de los dones más preciados del hombre: el sentido de la visión.

A study on 475 students have realized in Ocongate, a QÆosqoÆs district to determine the ocular pathology prevalence. The study found a prevalence rate of 7.8%. The most frequent ocular pathology were asthigmatis (3.2%), myopy and fotoelectric conjunctivitis (1.3% for both pathologies). The prevalence rate were higher in females (8.8%) than in males (7.1). The groups of age most affected were 5-9 for females and 10-14 for males. The authors concluded that the prevalence rate found was high and suggest that another descriptives studies about ocular pathology could be made, and the visual health programmes must be execute to preserve the visual sense.