Mutation and SARS-CoV-2 strain competition under vaccination in a modified SIR model.

The crisis caused by the COVID-19 outbreak around the globe raised an increasing concern about the ongoing emergence of variants of the virus that may evade the immune response provided by vaccines. New variants appear due to mutation, and as the cases accumulate, the probability of the emergence of a variant of concern increases. In this article, we propose a modified susceptible, infected, and recovered (SIR) model with waning immunity that captures the competition of two strain classes of an infectious disease under the effect of vaccination with a highly contagious and deadlier strain class emerging from a prior strain due to mutation. When these strains compete for a limited supply of susceptible individuals, changes in the efficiency of vaccines may affect the behaviour of the disease in a non-trivial way, resulting in complex outcomes. We characterise the parameter space including intrinsic parameters of the disease, and using the vaccine efficiencies as control variables. We find different types of transcritical bifurcations between endemic fixed points and a disease-free equilibrium and identify a region of strain competition where the two strain classes coexist during a transient period. We show that a strain can be extinguished either due to strain competition or vaccination, and we obtain the critical values of the efficiency of vaccines to eradicate the disease. Numerical studies using parameters estimated from publicly reported data agree with our theoretical results. Our mathematical model could be a tool to assess quantitatively the vaccination policies of competing and emerging strains using the dynamics in epidemics of infectious diseases.

Effects of pH and Application Technique of In-office Bleaching Gels on Hydrogen Peroxide Penetration into the Pulp Chamber.

OBJECTIVE: This in vitro study aimed to quantify the penetration of hydrogen peroxide (HP) into the pulp chamber in teeth submitted to in-office bleaching with varied pH and application techniques. The color change and pH of the in-office bleaching product during application was also evaluated. METHODS AND MATERIALS: Ninety-six human premolars were used and randomly divided into 10 groups (n=9) according to the following combination of factors: pH of in-office bleaching agents (two neutral/alkaline pH: Opalescence Boost 38% and Whiteness HP Blue 35% and three acidic pH: Whiteness HP Maxx 35%, Lase Peroxide Sensy 35%, and Total Blanc Office 35%) and application modes (for 3 × 15 minutes [3×15] and 1 × 45 minutes [1×45]). An additional group of non-bleached teeth (control; n=6) was added. First, all teeth were sectioned 3 mm from the cementoenamel junction and the pulp tissue was removed. An acetate buffer was placed in the pulp chamber of all teeth. After bleaching, this solution was transferred to a glass tube in which HP was allowed to react with other components, resulting in a pink solution. The optical density of this pink solution was measured using ultraviolet-visible spectroscopy and converted into amount of HP. Color change before and 1 week after bleaching was evaluated using a digital spectrophotometer. A pH meter with a 6-mm circular and flat surface was used in contact with the enamel surface to quantify the pH of the bleaching gels during application. Data were analyzed using two-way analysis of variance and Tukey tests (α=0.05). RESULTS: Overall, lower mean HP penetration values were observed for Opalescence Boost 38% and Whiteness HP Blue 35% compared with other bleaching gels (p<0.05). Opalescence Boost 38% and Whiteness HP Blue 35% were not influenced by the application technique (p>0.05). However, lower mean HP penetration values were observed for Whiteness HP Maxx 35%, Total Blanc Office 35%, and Lase Peroxide Sensy 35% when using the 3×15 application technique compared with the 1×45 technique (p<0.05). Significant whitening was detected and no significant difference of color change was observed between groups (p>0.54). The pH did not change during the 3×15 application technique; however, all acidic bleaching gels significantly decreased in pH when applied for 1×45 (p<0.01). CONCLUSIONS: The amount of HP that reaches the pulp chamber was lower when neutral/alkaline pH gels were used, independently of the application technique. When considering acidic pH gels, it is preferable to use the 3×15 application technique, mainly because longer application time (1×45) results in lower pH. No difference was observed between groups with regards to color change.

Effectiveness of In-office Hydrogen Peroxide With Two Different Protocols: A Two-center Randomized Clinical Trial.

OBJECTIVES: The aim of this study was to compare the bleaching efficacy and tooth sensitivity (TS) of a 38% hydrogen peroxide bleaching agent used for in-office bleaching, applied under different time protocols: a 40-minute application or two 20-minute applications. METHODS AND MATERIALS: Forty-four patients from Brazil and Colombia, with right superior canines darker than C2, were selected for this multicenter, single-blind, randomized trial. The teeth were bleached in two sessions, with a one-week interval between them, in a split-mouth design. The bleaching agent was applied in two 20-minute (2×20) applications or one 40-minute (1×40) application in each session according to the manufacturer's instructions. The color changes were evaluated by using subjective (Vita Classical and Vita Bleachedguide) and objective (Easyshade Spectrophotometer) methods at baseline and 30 days after the second session. Tooth sensitivity was recorded up to 48 hours with a 0-10 visual analog scale. Also, the pH values during the application of bleaching were recorded. Color change in shade guide units and ΔE were analyzed by using the Student t-test (α=0.05). The absolute risk and intensity of TS were evaluated with the McNemar test, the Wilcoxon signed-rank test, and the Friedman test, respectively (α= 0.05). RESULTS: Significant whitening was observed in both groups after 30 days of clinical evaluation. The use of a 40-minute application did not significantly influence the absolute risk of TS (68%, 95% confidence interval [CI] = 53-80) as well as the intensity of TS compared with the acid bleaching gel (absolute risk of 82%, 95% CI = 68-91). The pH values did not differ significantly between groups and at the different assessment periods ( p=0.42). CONCLUSION: The use of a 40-minute in-office bleaching agent gel application produced the same whitening degree and TS that the two 20-minute bleaching agent applications did. The former preferably should be applied because one 40-minute application does not require gel refreshing.

Randomized Double-blind Clinical Trial of Bleaching Products in Patients Wearing Orthodontic Devices.

OBJECTIVES: This double-blind randomized clinical trial evaluated tooth sensitivity (TS) and the effectiveness (EF) of two types of bleaching agents (Trèswhite Ortho [TWO] and Trèswhite Supreme [TWS]) when used in patients wearing orthodontic appliances. METHODS AND MATERIALS: Forty patients between the ages of 18 and 40 years were randomly stratified, with an equal allocation rate, into two groups (n=20), according to the bleaching agent applied. Tooth color of the six maxillary anterior teeth was measured before and after the treatment with a spectrophotometer. The TS was recorded on three scales before and during the bleaching treatment. RESULTS: With regard to EF, a significant reduction was found (ranging from 7.3-9.6 and 5.3-9.5 Vita scale units for TWO and TWS, respectively, p<0.001); however, there was no statistical difference between the groups (p>0.63). The number of patients with sensitivity was 58.8% and 73.3% for TWO and TWS groups, respectively (p=0.53); however, with each of the three scales used, the intensity of sensitivity was low and there was no statistical difference between TWO and TWS (p>0.05). CONCLUSIONS: In spite of producing a side effect of low TS, the two bleaching treatments tested were effective for dental bleaching in patients with fixed orthodontic appliances.

Coalescence cascade of dissipative solitons in parametrically driven systems.

Parametrically driven spatially extended systems exhibit uniform oscillations which are modulationally unstable. The resulting periodic state evolves to the creation of a gas of dissipative solitons. Driven by the interaction of dissipative solitons, the multisoliton state undergoes a cascade of coalescence processes, where the average soliton separation distance obeys a temporal self-similar law. Starting from the soliton pair interaction law, we have derived analytically and characterized the law of this multisoliton coarsening process. A comparison of numerical results obtained with different models such as the parametrically driven damped nonlinear Schrödinger equation, a vertically driven chain of pendula, and a parametrically forced magnetic wire, shows remarkable agreement. Both phenomena, the pair interaction law and the coarsening process, are also observed experimentally in a quasi-one-dimensional layer of Newtonian fluid which is oscillated vertically.

Adenoma tóxico como causa de hipertiroidismo en la infancia. Diagnóstico y tratamiento / Toxic adenoma as cause of hyperthyroidism in childhood. Diagnosis and treatment

El adenoma tóxico es una causa frecuente de hipertiroidismo en la edad adulta. No obstante, su baja prevalencia en la infancia hace de ésta una patología de especial interés, siendo motivo de discusión en la actitud terapéutica dado su mayor riesgo de malignidad. Describimos el caso de una paciente de 9 años de edad con una tumoración cervical anterior. En el estudio se detecta nódulo tiroideo hiperfuncionante con elevación de T3L, con diagnóstico definitivo de adenoma tóxico tiroideo en la anatomía patológica (AU)

The toxic adenoma is a common cause of hyperthyroidism in adulthood. However, its low prevalence in childhood makes it a condition of particular interest to be a matter of discussion in the therapeutic attitude due to its increased risk of malignancy. We describe the case of a 9 year-old patient with an anterior cervical tumour. The study detected thyroid nodule hiperfuncionante with elevated T3L, with a definitive diagnosis of toxic thyroid adenoma in the pathology (AU)

Euresis infantile: la importancia de una correcta intervención / Childhood enuresis: the importance of a correct intervention

Introducción: la enuresis nocturna monosintomática (ENM) es una enfermedad muy frecuente en la infancia que favorece la aparición de problemas psicológicos y de autoestima; sin embargo, sigue siendo una entidad infravalorada. Objetivos: 1. Conocer las características epidemiológicas y clínicas de una serie de niños enuréticos. 2. Seguir la evolución de estos pacientes desde que acudieron a nuestra consulta hasta el alta. Material y métodos: Estudio descriptivo retrospectivo incluyendo 67 niños derivados a una consulta hospitalaria durante los años 1997-2005 por presentar enuresis. Se recogieron los datos epidemiológicos, clínicos y terapéuticos antes y después de la visita a una consulta especializada. Resultados: Se revisaron 67 pacientes. 76,1% correspondieron a ENM y 23,9% a síndrome enurético. Presentamos 51 casos de ENM (66,7% niños y 33,3% niñas). Existían antecedentes familiares en el 80,4%. Solo el 47,1% había recibido tratamiento previo. La valoración psicosocial resultó normal en el 94,1% y la exploración física en el 92,2%. En el 78,4% se solicitaron pruebas complementarias. Los tratamientos más empleados fueron: pauta básica, desmopresina (45,1%) y desmopresina más anticolinérgicos (33,35%). Aparecieron efectos secundarios relacionados con la desmopresina en el 11,8%. Se curó el 74,5%. Conclusiones: Es necesario concienciar al paciente a sus familiares de este problema y fomentar el tratamiento precoz de la ENM. En la ENM la valoración básica psicosocial y la exploración física son casi siempre normales. Los exámenes complementarios pueden reducirse a un examen de orina. Recordar que el tratamiento requiere tiempo y detectar precozmente sus efectos secundarios es fundamental para evitar el abandono del mismo (AU)

Background. Nocturnal Enuresis is a common illness in childhood that involves psychological and self-esteem problems. However, enuresis is often misunderstood. Objective: 1. Review the main epidemiologic and clinical characteristics of a group of enuretic children. 2. Follow up of these patients from admission until discharge from hospital. Material and methods: Descriptive, retrospective study including 67 children sent to the out patient department during 199-2005 for enuresis. Epidemiological, clinical and treatment data were recorded before and after visiting the specialist. Results: 67 patients were reviewed: 76,1% were found to have Monosyptomatic Nocturnal Enuresis (MNE) and 23,9% were found to have enuretic syndrome. In this study we present 51 cases of MNE (66,7% male and 33,3% female under the age of fourteen years). There was a family history of nocturnal enuresis in 80,4%. In our experience we founded that only 47,1% had received treatment before they arrived at hospital. Psychosocial evaluation was normal in 94,1% and physical examination in 92,2%. In 78,4% of the patients routine exams were carried out. The most frequent treatments were: behavioral intervention, desmopressin 845,1%) and desmopressin + cholinergic antagonists (33,35%). Secondary effects related to desmopressin were observed in 11,8%. 74,5% of the subjects mad a good recovery from enuresis. Conclusions: it is important to make patient and family aware of this problem and to promote the early treatment of MNE. Basic psychosocial examination and physical examination are usually normal in MNE. Routine exams can be reduced to an urine exam. The treatment can be over long duration and the early detection of secondary effects is basic to avoid treatment abandonment (AU)

sexual en personas menores de edad. A propósito del estudio de tres casos. sexual en personas menores de edad. A propósito del estudio de tres casos / Valoración médica de la sospecha de abuso. Medical evaluation of sexual abuse suspicion in children. Report of three cases

El diagnóstico, la valoración y el tratamiento de menores que pueden haber sido víctimas de alguna forma de abuso sexual, constituye un problema emergente de salud que tiene implicaciones legales y sociales. Por la complejidad y diversidad de los factores que intervienen, su abordaje tiene que ser llevado a cabo con la colaboración de diferentes especialistas, profesionales de distintas disciplinas y por instituciones de varios sectores. A través de la revisión de tres casos se pretende expresar las dificultades que puede ofrecer el diagnóstico de abuso sexual en personas menores de edad, que como otros síndromes, se establece con un rango de probabilidad, basado en un proceso de valoración médica, psicológica y social; lo que no debe poner en cuestión el propio diagnóstico del abuso. Como conclusión fundamental se extrae que no siempre es posible obtener indicadores de certeza, y que no siempre coincidirán la valoración médica con la psicológica o con la social, o que las actuaciones judiciales no habrán de ser en todos los casos determinantes para que la entidad pública pueda adoptar medidas de protección

The diagnostic, valuation and treatment of children that could have been victims of any form of sexual abuse, is an emergent health problem with important legal and social implications. Because of the complexity and diversity of the factors that can be related to this issue, its study has to be done with the cooperation of a wide range of specialists, professionals of different disciplines and also institutions belonging to several sectors. Through the revision of three different cases our aim is to express the obstacles that can be created by the diagnostic of sexual abuse in minors. Such a diagnostic is established after a medical, psychological and social process, always in a probabilistic rank, still this fact must never create doubts about the diagnostic. As a conclusion just to insist in the fact that not always it is going to be possible to obtain certainty indicators, and also that the medical impression will not always coincide with the psychological or social one, as well as not always it is necessary to have the permission of the Court to obtain a response of the Public Administration

Atresia bronquial congénita asintomática en un varón de diez años / Asymptomatic congenital bronchial atresia in a 10-years-old boy

No disponible

Hernia diafragmática de Morgagni de presentación tardía / Delayed presentation of Morgagni diaphragmatic hernia

No disponible

Estudio cuasiexperimental de la eficacia del manejo fonoaudiológico en pacientes con disfagia, hospitalizados en la Clínica Carlos Lleras Restrepo / Cuasy-experimental assay of the speech language and hearing pathological handling effectivity for in bed patients at the Carlos Lleras Restrepo Clinic

Antecedentes. La disfagia orofaríngea que afecta con especial frecuencia a los ancianos y a los sobreviviente de enfermedad cerebrovascular, ocasiona morbinortalidad adicional en los pacientes/usuarios hospitalizados. Objetivo. Identificar fortalezas y debilidades del manejo fonoaudiológico de la disfagia orofaríngea en pacientes/usuarios hospitalizados en la Clínica Carlos Lleras Restrepo de Bogotá. Material y métodos. Mediante de la implementación de trece actividades en las cinco acciones fonoaudiológicas, se estableció una vigilancia continua al ingreso de los pacientes en los servicios de hospitalización. Se monitorizó el tiempo de detección de la alteración, su manejo multidisciplinar y el traslado al enfermo y a su familia de las estrategias adecuadas de manejo. Resultados. Hallamos cuatro situaciones que interfirieron en la acometida fonoaudiológica oportuna para esta población: un tardío proceso de detección, poco trabajo multidisciplinar integral, escasez en recursos humanos e insumos y dificultades en la transferencia de estrategias terapéuticas como cambios posturales y maniobras de deglución a la vida cotidiana. Se implementaron alternativas que incorporaron el proceso de detección temprana al protocolo de admisión en ambientes hospitalarios, promoción del servicio, y se recomendó la creación de un equipo multidisciplinar entre otras. Conclusión. La implementación de estrategias fonoaudilógicas que identifiquen y traten la disfagia orofaríngea oportunamente, ayuda a optimizar la calidad de los servicios hospitalarios y favorece la evolución de los pacientes y la colaboración de sus familiares

Asociación de absceso cerebral y cardiopatía congénita / Association of cerebral abscess and congenital cardiopathy

Analiza que el absceso cerebral constituye una entidad relevante entre las causas de mortalidad en países en desarrollo. En el Hospital de Niños Baca Ortiz, del Ecuador se estudia 30 casos de absceso cerebral encontrándose 8 pacientes portadores de cardiopatía congénita para determinar su influencia, comportamiento, factores añadidos y se demuestra la importancia del diagnóstico y tratamiento precoz de cardiopatías congénitas, así como la utilización de profilaxis.

Ileo biliar: nuestra experiencia / Biliary ileum: our experience

Objetivos: el presente trabajo tiene por objetivo presentar la experiencia en nuestro hospital y en la práctica privada, sobre el estudio, epidemiología, fisiopatología, clínica y tratamiento del ileo biliar. Material y métodos: se analiza una serie de 28 casos del ileo biliar tratados entre los años 1982 y 1998 en el Servicio de Guardia del HIGA San Martín y en la práctica privada. Resultados: los 29 pacientes fueron resueltos quirúrgicamente. La certeza diagnóstica se tuvo en 11 de ellos (37,9 por ciento), se lo sospechó en 5 (17,2 por ciento) y se ignoró en 13 (44,9 por ciento). Los hallazgos operatorios fueron en 21 72,4 por ciento) cálculo único y en 8 (

Ileo biliar: nuestra experiencia / Biliary ileum: our experience

Objetivos: el presente trabajo tiene por objetivo presentar la experiencia en nuestro hospital y en la práctica privada, sobre el estudio, epidemiología, fisiopatología, clínica y tratamiento del ileo biliar. Material y métodos: se analiza una serie de 28 casos del ileo biliar tratados entre los años 1982 y 1998 en el Servicio de Guardia del HIGA San Martín y en la práctica privada. Resultados: los 29 pacientes fueron resueltos quirúrgicamente. La certeza diagnóstica se tuvo en 11 de ellos (37,9 por ciento), se lo sospechó en 5 (17,2 por ciento) y se ignoró en 13 (44,9 por ciento). Los hallazgos operatorios fueron en 21 72,4 por ciento) cálculo único y en 8 (

Experiencia quirurgica en coartación de aorta

La coartacion de la aorta es una defecto obstructivoque constituye el 8 por ciento del total de pacientes portadores de malformaciones cardiacas. En el presente trabajo se estudiaron 42 pacientes sometidos a cirugía por coartación de aorta desde enero de 1986 a noviembre de 1992, comprendidos entre 1 mes y 29 años , 33 hombres (78.5 por ciento) y 9 mujeres (21.5 por ciento), proporción de 3.7:1.0. Anatomicamente se encontró coartación yuxtaductal en 22 pacientes (52.3 por ciento), preductal3 (7.2 por ciento) de itsmo 12 (28.5 por ciento), con hipoplasia de arco 2 (4.8 por ciento), mixta 3 (7.2 por ciento) y coartación de aorta con otros defectos en 29 casos. Se utilizaron como técnicas quirurgicas: La anastomosis en 14 casos(33.4 por ciento), colocación de tubo en 3 (7.1 por ciento), Telles 14 (33.4 por ciento), aortoplasia 11(26.1 por ciento). De todos los pacientes estudiados, únicamente 8 presentaron compliaciones tempranas, 7 con crisis hipertensiva (16.6 por ciento) y 1 sección de conducto toraxico (2.3 por ciento), no se presentaron complicaciones tardias. Se plantea la utilidad de un diagnostico a menor edad e intervención quirurgica temprana.