Simulation of pandemics in real cities: enhanced and accurate digital laboratories.

This study develops a modelling framework for simulating the spread of infectious diseases within real cities. Digital copies of Birmingham (UK) and Bogotá (Colombia) are generated, reproducing their urban environment, infrastructure and population. The digital inhabitants have the same statistical features of the real population. Their motion is a combination of predictable trips (commute to work, school, etc.) and random walks (shopping, leisure, etc.). Millions of individuals, their encounters and the spread of the disease are simulated by means of high-performance computing and massively parallel algorithms for several months and a time resolution of 1 minute. Simulations accurately reproduce the COVID-19 data for Birmingham and Bogotá both before and during the lockdown. The model has only one adjustable parameter calculable in the early stages of the pandemic. Policymakers can use our digital cities as virtual laboratories for testing, predicting and comparing the effects of policies aimed at containing epidemics.

In vitro rumen biohydrogenation kinetics of mixed linoleic and alfa-linolenic acids / Cinética de biohidrogenación ruminal in vitro de los ácidos linoleico y alfa-linolénico mezclados / Cinética de biohidrogenação ruminal in vitro dos ácidos linoleico e alfa-linolênico misturados

Abstract Background: Dietary linoleic (LA) and alpha-linolenic (LN) acids are extensively isomerized and hydrogenated by rumen microbes, and this activity can further contribute to the fatty acid profile of ruminant- derived food products. Objective: To evaluate the effects of LA:LN ratio in lipid supplements on the rumen biohydrogenation kinetics of LA and LN, as well as on the trans-vaccenic acid (VA) production, using an in vitro system. Methods: Rumen fluid was collected from a fistulated steer, diluted with incubation buffer, and then incubated with 500 mg of kikuyu grass (Cenchrus clandestinus) supplemented with 16.3 mg of different LA:LN mixtures (100:0, 75:25, 50:50, 25:75 or 0:100). Incubations were performed in triplicate for a period of 0, 2, 4, 6, 8 or 16 hours. Differences between treatments were evaluated in a completely randomized design. Alternatively, computational chemistry was used to determine the changes in the Gibbs free energy (ΔGrxn) at 39 °C for the principal steps of LA and LN ruminal biohydrogenation. Results: Partial replacement of LA by LN decreased the VA concentration and its accumulation rate; it also increased the stearic acid concentration and the rates of transfer from LA to conjugated linoleic acid (CLA), and from CLA to VA. The conversion from CLA to VA (ΔGrxn = -2.65 kJ/mol) was more spontaneous than that from trans-11, cis-15 octadecadienoic acid (TA) to VA (ΔGrxn = -0.29 kJ/mol). Conclusion: The LA:LN ratio in lipids can modulate LA and LN biohydrogenation (BH) kinetics, as well as the VA production in the rumen.

Resumen Antecedentes: los ácidos linoleico (LA) y alfa-linolénico (LN) de la dieta son extensivamente isomerizados y biohidrogenados por los microorganismos ruminales, lo cual puede contribuir al perfil de ácidos grasos de los productos derivados de rumiantes. Objetivo: evaluar el efecto de la relación LA:LN en suplementos lipídicos sobre la cinética de biohidrogenación ruminal del LA y LN, como también sobre la producción del ácido trans-vaccénico (VA), usando un sistema in vitro. Métodos: se colectó fluido ruminal de un toro fistulado, el cual fue diluido con buffer de incubación y posteriormente incubado con 500 mg de pasto kikuyo (Cenchrus clandestinus) suplementado con 16,3 mg de diferentes mezclas de LA:LN (100:0, 75:25, 50:50, 25:75, o 0:100). Las incubaciones fueron desarrolladas en triplicado durante 0, 2, 4, 6, 8 o 16 horas. Diferencias entre tratamientos fueron evaluadas mediante un modelo completamente al azar. Alternativamente, se determinaron los cambios en energía libre de Gibbs ( Δ Grxn) a 39 °C para los pasos principales de la biohidrogenación del LA y LN, usando química computacional. Resultados: la sustitución parcial de LA por LN disminuyó la concentración de VA y su tasa de acumulación, como también incrementó la concentración de ácido esteárico y las tasas de transferencia de LA para ácido linoleico conjugado (CLA) y de CLA para VA. La conversión de CLA para VA ( Δ Grxn = -2,65 kJ/mol) fue más espontánea que la conversión del ácido trans-11, cis-15 octadecadienóico (TA) para VA ( Δ Grxn = -0,29 kJ/mol). Conclusiones: la relación LA:LN en lípidos puede modular la cinética de biohidrogenación (BH) del LA y LN y la producción de VA en el rumen.

Resumo Antecedêntes: o ácido linoleico (LA) e alfa-linolênico (LN) da dieta, são extensivamente isomerizados e biohidrogenados pelos microorganismos do rúmen, o que pode contribuir ao perfil de ácidos graxos dos produtos derivados de ruminantes. Objetivo: avaliar o efeito da relação LA:LN em suplementos lipídicos sobre a cinética de biohidrogenação ruminal do LA e LN como também sobre a produção do ácido trans- vaccênico (VA), utilizando um sistema in vitro. Métodos: coletou-se fluido ruminal de um novilho fistulado, o qual foi diluído com tampão de incubação e, em seguida, incubado com 500 mg de pasto kikuyu (Cenchrus clandestinus) suplementado com 16,3 mg de diferentes misturas LA:LN (100:0, 75:25 , 50:50, 25:75 ou 0:100). As incubações foram desenvolvidas em triplicata, durante 0, 2, 4, 6, 8 ou 16 horas. Diferenças entre tratamentos foram avaliadas utilizando-se um delineamento inteiramente casualizado. Alternativamente, foram determinadas as mudanças em energia livre de Gibbs ( Δ Grxn) a 39 °C para as principais etapas da biohidrogenação do LA e LN, utilizando-se química computacional. Resultados: a substituição parcial de LA por LN diminuiu a concentração de VA e sua taxa de acumulação, como também aumentou a concentração de ácido esteárico e as taxas de transferência do LA para o ácido linoleico conjugado (CLA) e do CLA para VA. A conversão do CLA para VA ( Δ Grxn = -2,65 kJ/ mol) foi mais espontânea que a conversão do ácido trans-11, cis-15 octadecadienóico (TA) para VA ( Δ Grxn = -0,29 kJ/mol). Conclusões: a relação LA:LN em lipídeos pode modular a cinética de biohidrogenação (BH) do LA e LN e a produção de VA no rúmen.

Modeling spatial patterns in the visual cortex.

We propose a model for the formation of patterns in the visual cortex. The dynamical units of the model are Kuramoto phase oscillators that interact through a complex network structure embedded in two dimensions. In this way the strength of the interactions takes into account the geographical distance between units. We show that for different parameters, clustered or striped patterns emerge. Using the structure factor as an order parameter we are able to quantitatively characterize these patterns and present a phase diagram. Finally, we show that the model is able to reproduce patterns with cardinal preference, as observed in ferrets.

Signos de alarma en proctocolitis eosinofílica: reporte de dos casos / Warning Signs for Eosinophilic Proctocolitis: Two Case Reports

Se presentan dos pacientes con un diagnóstico de proctocolitis eosinofílica sin persistencia de la manifestación más típica, la rectorragia, aunque con perseverancia de su compromiso inflamatorio eosinofílico. A propósito de estos casos, se señala la importancia de evaluar otras manifestaciones menos relevantes como parte del seguimiento estricto de los pacientes, con el fin de decidir si necesitan colonoscopia y biopsias, así como de reorientar el manejo mediconutricional.

We present the cases of two patients diagnosed with eosinophilic proctocolitis without persistence of rectal bleeding which is the most typical manifestation but with perseverance of the eosinophilic inflammation. One purpose of presenting these cases is to emphasize the importance of assessing less relevant demonstrations as part of the strict monitoring of patients in order to decide whether they need colonoscopy and biopsies and to allow redirection of medical nutrition management.

El miembro asimétrico (gigantismo): aproximación diagnóstica / The asymmetric limb (gigantism): diagnostic approach

Las enfermedades que cursan con desarrollo asimétrico de una de las extremidades son entidades raras y se consideran un reto para los radiólogos. Dentro de estas entidades encontramos la macrodistrofia lipomatosa, el síndrome de Proteus, el síndrome de Maffucci y el síndrome de Klippel-Trenaunay-Weber. Es importante conocer los hallazgos radiológicos de las enfermedades que se caracterizan por gigantismo, para lograr un diagnóstico acertado.

Radial scan of the molecular electrostatic potential of RNA double helices: an application to the enzyme-tRNA recognition.

We introduced a method to characterize quantitatively the molecular electrostatic potential (MEP) of the minor and major grooves of base pairs located at nucleic acid double helices. By means of a radial MEP scan, we obtained a n-tuple of potential values corresponding to each groove, which can be analyzed by plotting the MEP values as a function of the angle in the radial scan. We studied base pairs of two different tRNAs, relevant in the recognition process with their cognate aminoacyl tRNA synthetases (aaRSs), in order to correlate their electrostatic behavior with the corresponding aminoacylation activity. We analyzed the first three base pairs of the Escherichia coli tRNA(Ala) acceptor stem, finding several cases where the MEP profiles obtained from the plots are in agreement with the reported aminoacylation activities. Additionally, a non-hierarchical clustering performed over the MEP n-tuples resulted in meaningful classifications that correlate with the activity and with the predicted stereochemistry of the reaction. We also studied the first two base pairs of the E. coli tRNA(Thr) acceptor stem but constraining the analysis to the angle intervals that seem relevant for the binding sites of the enzyme. These intervals were deduced from the ThrRS-tRNA(Thr) complex crystal structure. In this case, we also found a good agreement between the MEP profiles and the activity, supporting the idea that the tRNA identity elements function is to allow an optimal electrostatic complementarity between the aminoacyl-tRNA synthetase and the tRNA.

Oral montelukast versus inhaled beclomethasone in 6- to 11-year-old children with asthma: results of an open-label extension study evaluating long-term safety, satisfaction, and adherence with therapy.

This 6-month, open-label extension study of a previously described base study compared oral montelukast with inhaled beclomethasone in terms of safety, forced expiratory volume in one second (FEV1) measurements, parent and patient satisfaction with treatment, asthma-related medical resource utilization, school absenteeism, and parental work loss in children with asthma. A total of 124 of 266 asthmatic children, 6 to 11 years of age, who enrolled in the base study entered a 6-month open-label extension study (74 boys, 50 girls) and were re-randomized (2:1 ratio) to receive once-daily oral montelukast (n = 83) or inhaled beclomethasone 100 mcg three times daily (n = 41). Children were evaluated in the clinic prior to re-randomization (Month 0) and at regular visits at 1, 3, and 6 months. Children and their parents showed a significantly higher overall satisfaction for montelukast at 6 months than for inhaled beclomethasone (p = 0.001 and p < 0.05, respectively). According to parents, montelukast was more convenient (p < 0.001), less difficult to use (p = 0.005), and was used as instructed more of the time (p = 0.006) compared with beclomethasone. Oral corticosteroid use was similar in the montelukast (13% of patients) and beclomethasone (17%) treatment groups. The montelukast treatment group was more adherent with their regimen than the inhaled beclomethasone treatment group; almost twice as many children on montelukast compared with inhaled beclomethasone were highly compliant (82% versus 45%). The two study groups were similar with respect to overall safety, change in FEV1, asthma-related medical resource utilization, school absenteeism, and parental work loss. Montelukast represents a safe and effective asthma treatment regimen to which children with asthma are more likely to adhere.

Multiresistant extended-spectrum beta-lactamase-producing Klebsiella pneumoniae causing an outbreak of nosocomial bloodstream infection.

This article describes an outbreak of bloodstream infection due to clonal dissemination of multiresistant Klebsiella pneumoniae in a neonatal area, during August 1999, in Mexico City General Hospital. The intestinal tract was the likely reservoir, and intensification of Contact Precaution measures contained the outbreak.

Outbreak of nosocomial sepsis and pneumonia in a newborn intensive care unit by multiresistant extended-spectrum beta-lactamase-producing Klebsiella pneumoniae: high impact on mortality.

We describe a case-control study of a small outbreak of nosocomial sepsis and pneumonia with high mortality due to clonal dissemination of a multiresistant Klebsiella pneumoniae in the neonatal intensive care unit of a Mexican institution. Our study helped to change nosocomial infection control policy in this hospital.

Endoscopía digestiva alta en pacientes pediátricos / Upper digestive endoscopy in pediatric patients

Se describen las indicaciones médicas y los hallazgos de las endoscopias digestivas altas en los pacientes atendidos en un policlínico de gastroenterología pediátrica de un hospital general de Santiago Metropolitano entre julio de 1992 y diciembre de 1995. Se hicieron 926 endoscopias altas, 385 en niños y 541 en niñas. La edad de los pacientes oscilaba entre 1 mes y 15 años (6,7 ñ 4,5 años). La mayoría de los procedimientos se indicó por dolor abdominal recurrente (20,8 por ciento), con el objetivo de descartar afecciones orgánicas: en lactantes por reflujo gastroesofágico (35,3 por ciento), en preescolares la causa más frecuente fue hipertensión portal (46,7 por ciento); en escolares se indicó principalmente por dolor abdominal recurrente (25 por ciento) y en adoelscentes por hemorragia digestiva alta (37,5 por ciento). En un cuarto de los casos los resultados de la endoscopia fueron normales, la esofagitis fue el hallazgo endoscópico más frecuente en los lactantes (30,3 por ciento) y en los preescolares (26,7 por ciento); esofagitis y várices esofágicas (18,8 por ciento para ambos) en escolares y las úlceras duodenales en los adolescentes (29,2 por ciento), en corcondancia con los signos clínicos que motivaron la indicación. La endoscopia digestiva alta es un método poco complejo y útil en el diagnóstico diferencial de las enfermedades gastrintestinales de los niños

[Prevalence and sociocultural and economic aspects of hypertension in a health center of the northern area of Manaus]. / Prevalência e aspectos sócio-culturais e econômicos da hipertensão arterial em centro de saúde da zona norte de Manaus.

PURPOSE: To verify the prevalence and the possible sociocultural and economic factors involved in high blood pressure (HBP), intending to contribute to the elaboration of public health programs. METHODS: The blood pressure of 1,766 individuals, aging 13 years old or more, was measured by the auscultatory method, using a stethoscope and a sfigmomanometer. It was included in the HBP group, the individual presenting blood pressure above 140 x 90 mmHg in two measurements on different occasions. These individuals answered a form searching for sociocultural and economic aspects. RESULTS: Among the individuals examined, 76 were considered to have HBP. There was an increase on the prevalence of HBP with an increase of age, being the greatest among the individuals aging 49 years or more. It was observed significant association between age and HBP (p < 0.05), but the same did not happen with sex or skin color. In most part of the individuals with HBP, it was observed low family income and low educational level. Half of the HBP patients were used to eat with salt and fat. CONCLUSION: The educational level, economic status, and sociocultural habits of a person constitute factors that must be considered in the development of public health programs for control and reduction of the prevalence of HBP.

[Evaluation of three new culture media: brilliant-glycerol-lactose novobiocin-green agar, modified iron lysin agar and Rambach agar for the isolation of enteropathogenic E. coli, Salmonella sp. in acute gastroenteritis]. / Valoración de tres nuevos medios de cultivo: agar novobiocina-verde brillante-glicerol-lactosa, agar lisina-hierro modificado y agar Rambach para el aislamiento de E. coli enteropatógeno, Salmonella sp. y Shigella sp. en la gastroenteritis aguda.

BACKGROUND: Acute gastroenteritis (AGE) is one of the most common diseases in children, particularly in those under the age of 5 years in whom a severe picture of hydroelectrolyte imbalance may be triggered accompanied, in most cases, by leukocyte response. The aim of this study was to evaluate three new culture media for the isolation of enteropathogens in infantile diarrhea. MATERIAL AND METHODS: From April to September, 1993, 170 samples of diarrhea stools from children up to 7 years of age attending pediatric hospitals in Bogota were studied. Three new culture media were used in the isolation of the enteropathogenic bacteria: BGLN, MILA agar, Rambach agar and a conventional agar medium S.S. Biochemical tests were performed to identify the isolated bacteria. RESULTS: A total of 98.5% of enteropathogenic E. coli was isolated in Rambach agar, which also presented excellent recovery rates of Salmonella sp. (100%) versus S.S> (64.3%) and BGLN (77.2%), respectively. The best selectivity for Shigella sp. was observed with BGLN with a 100% recovery rate. Out of the 170 samples 105 showed a leukocyte count of 70-75% and positive isolation for enteropathogenic bacteria. Six samples with the same leukocyte count did not present enteropathogenic bacteria, with the 59 remaining samples with a 20-25% PMN count being negative for enteropathogenic bacteria. CONCLUSIONS: The results suggest that the new culture media used in this study may have better recovery rates for enteropathogenic bacteria in acute gastroenteritis. Likewise, a correlation was observed between leukocyte count and isolation enteropathogenic bacteria.

[Ultrasonography: the diagnostic method of choice in hypertrophic pyloric stenosis. Experience with 67 patients]. / Ultrasonografía: el método diagnóstico de elección en estenosis hipertrófica del píloro. Experiencia en 67 pacientes.

Hypertrophic pyloric stenosis (HPS) is a common medical emergency in newborns and lactating infants. Ultrasonography (US) is the diagnostic imaging procedure of choice in most centers, leaving the radiological study with barium for those cases in which US is negative and clinical symptoms persist or when other causes of vomiting must be discarded. We report our experience in 67 children (58 male) with suspected HPS. The US findings were consistent with HPS in 45 patients, and the diagnosis was surgically confirmed in all. In the remaining 22 patients with negative US findings, symptoms improved during follow up, with medical treatment. In one patient US was negative for HPS but showed an antral web, that was surgically confirmed. Since there were no false positive or negative results, the specificity and sensitivity of US for HPS diagnosis was 100%. We strongly recommend the use of US in patients with suspected HPS.

[Ultrasonography in spinal dysraphism and tethered cord]. / Ultrasonografía en la disrafia espinal y la médula anclada.

Spinal dysraphism is relatively common in children and includes a wide spectrum of congenital anomalies in the normal closure of the posterior elements of the spine. The prognosis will depend mostly on early diagnosis and treatment. Occult spinal dysraphism may present without external anomalies and the diagnosis could be suspected lately, when neurological symptoms are present and often irreversible. Occult spinal dysraphism is frequently associated to a tethered cord, most commonly secondary to the presence of a lipoma. Ultrasonography has been proven highly sensitive in the detection of intraspinal anomalies, especially in the diagnosis of tethered cord, in children under two years of age due to lack of ossification of the posterior elements of the spine. Today ultrasonography should be the examination of choice in all those patients in whom some kind of spinal dysraphism is suspected. We report our experience with three infants with occult spinal dysraphism in whom diagnosis was initially made by US and later on proved by either computed tomography, magnetic resonance or myelography. All of them had corrective surgery and neurological abnormalities were not detected afterwards.

[Ultrasonographic diagnosis of hypertrophic pyloric stenosis]. / Ultrasonido en el diagnóstico de estenosis hipertrófica del píloro.

Hypertrophic pyloric stenosis (HPS) is one of the most common causes of abdominal surgery during the first weeks of life. The primary cause of the muscular hypertrophy is unknown and the pathogenesis is obscure. Clinically, vomiting is always present and sometimes there is a palpable pyloric mass (olive). Upper gastrointestinal tract study with barium has been the most usual method for the diagnosis. Since the first report of the use of ultrasound (US) in the diagnosis of HPS in 1977, this technique has been widely used and accepted, being by now, the diagnostic imaging examination of choice for infants in whom this abnormality is suspected. This is our experience with the use of US in 27 infants with clinically suspected HPS. In 17 cases there was US evidence of HPS and in 10 patients results were negative. We did not have false positive neither false negative results. We strongly recommend this diagnostic method for all infants under clinical suspicion of HPS.

From food basket to food security. The food factor in nutritional surveillance.

One important indicator of nutritional surveillance is the one devoted to monitor food security. The experience toward the development of one of such indicators is presented. This includes the development of a food basket, defined as the group of foods that meet the characteristics such as is now consumed by important population segments of the community; it contributes a substantial portion of the calories and proteins purchased, and is responsible for an important proportion of the food budget. The concept implies a dynamic food basket, the quantities of which are calculated in a way that simulates the behavior of the consumer and the best nutrition knowledge. For this purpose we use linear program techniques. A measure of the risk of being unable to buy the foods needed for a family is presented, and is used as a proxy for food security risk. In the appendix, the mathematical expressions of the model used for a linear program is also presented.

From food basket to food security. The food factor in nutritional surveillance

One important indicator of nutritional surveillance is the one devoted to monitor food security. The experience toward the development of one of such indicators is presented. This includes the development of a food basket, defined as the group of foods that meet the characteristics such as is now consumed by important population segments of the community; it contributes a substantial portion of the calories and proteins purchased, and is responsible for an important proportion of the food budget. The concept implies a dynamic food basket, the quantities of which are calculated in a way that simultates the behavior of the consumer and the best nutrition knowledge. For this purpose we use linear program techniques. A measure of the risk of being unable to buy the foods needed for a family is presented, and is used as a proxy for food security risk. In the appendix, the mathematical expressions of the model used for a linear program is also presented

Participacion del sector salud en un sistema de vigilancia nutricional. / Participation of health sector in a nutritional surveillance system

Muchos paises tratan ahora de formular politicas y ejecutar programas de alimentacion y nutricion que requieren una vigilancia continua de su evolucion. El sector de la salud esta en posicion adecuada para desempenar un papel fundamental en la vigilancia nutricional, siempre que se hagan modificaciones en los sistemas de informacion y se difundan experiencias metodologicas sobre su desarrollo y aplicacion