Scaling Analysis of an Image Encryption Scheme Based on Chaotic Dynamical Systems.

Despite that many image encryption systems based on chaotic or hyperchaotic systems have been proposed to protect different kinds of information, it has been crucial to achieve as much security as possible in such systems. In this sense, we numerically implement a known image encryption system with some variants, making special emphasis when two operations are considered in the scrambling stage. The variants of such an encryption system are based on some hyperchaotic systems, which generated some substitution boxes and the keys of the system. With the aim to have a more complete evaluation, some internal stages of the image encryption scheme have been evaluated by using common statistical tests, and also the scaling behavior of the encrypted images has been calculated by means of a two-dimensional detrended fluctuation analysis (2D-DFA). Our results show that the image encryption systems that include two operations or transformations in the scrambling stage present a better performance than those encryption systems that consider just one operation. In fact, the 2D-DFA approach was more sensitive than some common statistical tests to determine more clearly the impact of multiple operations in the scrambling process, confirming that this scaling method can be used as a perceptual security metric, and it may contribute to having better image encryption systems.

Liver damage in bleomycin-induced pulmonary fibrosis in mice.

Pulmonary fibrosis is an emerging disease with a poor prognosis and high mortality rate that is even surpassing some types of cancer. This disease has been linked to the concomitant appearance of liver cirrhosis. Bleomycin-induced pulmonary fibrosis is a widely used mouse model that mimics the histopathological and biochemical features of human systemic sclerosis, an autoimmune disease that is associated with inflammation and expressed in several corporal systems as fibrosis or other alterations. To determine the effects on proliferation, redox and inflammation protein expression markers were analyzed by immunohistochemistry. Analyses showed a significant increase in protein oxidation levels by lipoperoxidation bio-products and in proliferation and inflammation processes. These phenomena were associated with the induction of the redox status in mice subjected to 100 U/kg bleomycin. These findings clearly show that the bleomycin model induces histopathological alterations in the liver and partially reproduces the complexity of systemic sclerosis. Our results using the bleomycin-induced pulmonary fibrosis model provide a protocol to investigate the mechanism underlying the molecular alteration found in the liver linked to systemic sclerosis.

Exploring the ancestry and admixture of Mexican Oaxaca Mestizos from Southeast Mexico using next-generation sequencing of 11 HLA loci.

The Mestizos of Oaxaca resulted from the admixture of Zapotecan Natives with Spaniards and Africans. We selected 112 donors from Oaxaca and applied next-generation sequencing to characterize exon and intron variants in complete or extended HLA genes. Some alleles found, are unique to Mexican Natives and most likely will be absent in most major ethnicities, namely: Caucasians, Africans or Asians. Among these are HLA-A*68:03:01, HLA-A*68:05:01, HLA-C*03:04:01:02, HLA-C*15:09, HLA-C*3:05, HLA-C*03:06:01, HLA-B*39:05:01, HLA-B*35:14:01, HLA-B*35:12:01, HLA-B*35:43:01, HLA-B*40:05, HLA-B:40:08, HLA-B*51:02:01, HLA-B*35:24:01 and HLA-B*39:08. HLA-DQA1*05:05:01:05 and some HLA-DRB1 alleles were only present in Amerindians/Mestizos. Three haplotypes are unique to Mexican Natives, five to Middle-Eastern and Sephardi-Jews. We detected a novel HLA-DQA1*04:01:01 exon 4 variant. Any novel allele may have been positively selected to enlarge the peptide-binding repertoire, and some, like HLA-B*39:02:02 and HLA-B*39:05:01 were found with unique haplotype associations, suggesting convergent evolution events and/or allele lineage diversification. The allele frequencies were fairly evenly distributed in most HLA loci with the exception of HLA-DPB1. The application of NGS in Oaxaca is novel and will lead to better use in the clinical setting. It offers deep knowledge on the population structure, origins, migration, and discovery of new alleles and haplotypes that other techniques did not achieve.

Allele diversity of the killer cell immunoglobulin-like receptors KIR3DL1/S1 and the combination with their HLA ligands in Mexican Mestizos from Mexico City.

Killer cell immunoglobulin-like receptors (KIRs), expressed on Natural Killer (NK) cells, activate/inhibit NK cell function through interactions with their HLA-A, B and C ligands. KIR3DL1 is one of the most polymorphic genes and its effect varies depending on the interaction of the specific allotype with its Bw4 ligand. We investigated the allelic diversity of KIR3DL1/S1 using sequence based typing and we typed as well, their Bw4 ligands in Mexican Mestizos of Mexico City. The results showed that this population has a great KIR3DL1 allelic diversity with ∗01502 (19.9%), ∗00101 (13.2%) and ∗00501 (12.8%) being the most common alleles, while KIR3DS1 showed predominance of ∗01301 (86%); these data agree with the diversity found in most populations studied. At least one KIR3DL1-HIGH surface expression allele was present in 67.5% of the subjects. Phylogenetic comparisons between Mestizos and 28 different populations showed that allelic diversity of KIR3DL1/S1 was similar in Mexican Mestizos from Mexico and in Hispanics from USA. Knowledge of KIR and MHC diversity worldwide is fundamental for understanding the impact of KIR and KIR-ligand polymorphism on NK cell effector functions and is relevant in genetic anthropology, disease association and transplantation.

Recommendations for the prevention and diagnosis of asthma in children: Evidence from international guidelines adapted for Mexico.

BACKGROUND: With the availability of high-quality asthma guidelines worldwide, one possible approach of developing a valid guideline, without re-working the evidence, already analysed by major guidelines, is the ADAPTE approach, as was used for the development of National Guidelines on asthma. METHODS: The guidelines development group (GDG) covered a broad range of experts from medical specialities, primary care physicians and methodologists. The core group of the GDG searched the literature for asthma guidelines 2005 onward, and analysed the 11 best guidelines with AGREE-II to select three mother guidelines. Key clinical questions were formulated covering each step of the asthma management. RESULTS: The selected mother guidelines are British Thoracic Society (BTS), GINA and GEMA 2015. Responses to the questions were formulated according to the evidence in the mother guidelines. Recommendations or suggestions were made for asthma treatment in Mexico by the core group, and adjusted during several rounds of a Delphi process, taking into account: 1. Evidence; 2. Safety; 3. Cost; 4. Patient preference - all these set against the background of the local reality. Here the detailed analysis of the evidence present in BTS/GINA/GEMA sections on prevention and diagnosis in paediatric asthma are presented for three age-groups: children with asthma ≤5 years, 6-11 years and ≥12 years. CONCLUSIONS: For the prevention and diagnosis sections, applying the AGREE-II method is useful to develop a scientifically-sustained document, adjusted to the local reality per country, as is the Mexican Guideline on Asthma.

Correlación entre la fiebre y la frecuencia respiratoria en menores de 5 años / Correlation between fever and respiratory rate in children under 5 years of age

Introducción: Entre los efectos de la fiebre está el incremento de la frecuencia respiratoria (FR) hasta alcanzar rangos de generar taquipnea. El diagnóstico de neumonía según la OMS basado en la presencia de taquipnea puede sobreestimarse durante la fiebre. El objetivo de este estudio fue determinar la correlación entre fiebre y FR en niños febriles menores de 5 años. Pacientes y Método: Estudio prospectivo de correlación en niños entre 2 y 60 meses. Se midió FR y temperatura corporal al ingreso a Servicio de Urgencia y luego de recibir acetaminofén. Se calculó la correlación entre el cambio de temperatura y el cambio en la FR. Se determinó la frecuencia de taquipnea al ingreso y al normalizar la temperatura. Resultados: 362 pacientes fueron incluidos, media 23,7 meses (DE 16,1). La FR en menores de un año disminuyó 12,9 respiraciones por minuto (DE 6,7) al normalizar temperatura; en mayores, disminuyó 10,7 respiraciones por minuto (DE 5,2). El coeficiente r² entre temperatura y FR fue 0,08 para menores de un año y 0,11 para mayores. De los niños que estaban taquipneicos, 57 por ciento no lo estaban al normalizar la temperatura. Conclusiones: Se recomienda reevaluar la FR de todo niño febril luego de normalizar su temperatura antes de definir taquipnea.

Introduction: Increased body temperature results in raised respiratory rate (RR) leading to tachypnea. According to World Health Organization (WHO), the diagnosis of pneumonia based on the presence of tachypnea can be overestimated during fever. The aim of this study is to determine the correlation between fever and RR in febrile children under five years of age. Patients and Method: A prospective study of correlation in children between 2 and 60 months was performed. RR and body temperature were measured on Emergency Room admission and after receiving acetaminophen. The correlation between the temperature change and the change in the RR was calculated. The frequency of tachypnea at admission and after normalizing the temperature was determined. Results: 362 patients were included, mean age 23.7 months old. RR in children under one year of age decreased 12.9 breaths per minute after normalizing the temperature, in older than one year of age, it decreased 10.7 breaths per minute. The r² coefficient between temperature and RR was 0.08 for children under one year and 0.11 for older. Among the children who were tachypneic, 57 percent did not present this condition after normalizing the temperature. Conclusions: It is recommended to reevaluate RR in all febrile children after normalizing the temperature and before diagnosing tachypnea.

Leishmania mexicana lipophosphoglycan differentially regulates PKCalpha-induced oxidative burst in macrophages of BALB/c and C57BL/6 mice.

Leishmania are protozoan parasites that infect macrophages and their survival is partially achieved through inhibition of the cellular oxidative burst by parasite lipophosphoglycan (LPG). PKCalpha is the predominant PKC isoenzyme required for macrophage oxidative burst, yet it is not known if different susceptibility of BALB/c and C57BL/6 mice to Leishmania mexicana could be related to PKCalpha. We analysed the effect of L. mexicana promastigotes and parasite LPG on expression of PKCalpha and on its activity in macrophages of both mouse strains. Our data show that expression of the isoenzyme was not altered either by LPG or by L. mexicana promastigotes. Yet LPG exerted opposing effects on PKCalpha activity of macrophages between both strains: in susceptible BALB/c cells, it inhibited PKCalpha activity, whereas in the more resistant strain it augmented enzymatic activity 2.8 times. In addition, LPG inhibited oxidative burst only in susceptible BALB/c macrophages and the degree of inhibition correlated with parasite survival. Promastigotes also inhibited PKCalpha activity and oxidative burst in macrophages of BALB/c mice, whereas in C57BL/6, they enhanced PKCalpha activity and oxidative burst inhibition was less severe. Our data indicate that control of PKCalpha-induced oxidative burst by L. mexicana LPG relates with its success to infect murine macrophages.

Modeling disease vector occurrence when detection is imperfect: infestation of Amazonian palm trees by triatomine bugs at three spatial scales.

BACKGROUND: Failure to detect a disease agent or vector where it actually occurs constitutes a serious drawback in epidemiology. In the pervasive situation where no sampling technique is perfect, the explicit analytical treatment of detection failure becomes a key step in the estimation of epidemiological parameters. We illustrate this approach with a study of Attalea palm tree infestation by Rhodnius spp. (Triatominae), the most important vectors of Chagas disease (CD) in northern South America. METHODOLOGY/PRINCIPAL FINDINGS: The probability of detecting triatomines in infested palms is estimated by repeatedly sampling each palm. This knowledge is used to derive an unbiased estimate of the biologically relevant probability of palm infestation. We combine maximum-likelihood analysis and information-theoretic model selection to test the relationships between environmental covariates and infestation of 298 Amazonian palm trees over three spatial scales: region within Amazonia, landscape, and individual palm. Palm infestation estimates are high (40-60%) across regions, and well above the observed infestation rate (24%). Detection probability is higher ( approximately 0.55 on average) in the richest-soil region than elsewhere ( approximately 0.08). Infestation estimates are similar in forest and rural areas, but lower in urban landscapes. Finally, individual palm covariates (accumulated organic matter and stem height) explain most of infestation rate variation. CONCLUSIONS/SIGNIFICANCE: Individual palm attributes appear as key drivers of infestation, suggesting that CD surveillance must incorporate local-scale knowledge and that peridomestic palm tree management might help lower transmission risk. Vector populations are probably denser in rich-soil sub-regions, where CD prevalence tends to be higher; this suggests a target for research on broad-scale risk mapping. Landscape-scale effects indicate that palm triatomine populations can endure deforestation in rural areas, but become rarer in heavily disturbed urban settings. Our methodological approach has wide application in infectious disease research; by improving eco-epidemiological parameter estimation, it can also significantly strengthen vector surveillance-control strategies.

Field ecology of sylvatic Rhodnius populations (Heteroptera, Triatominae): risk factors for palm tree infestation in western Ecuador.

Most Rhodnius species (Triatominae) are primarily associated with palm trees. They maintain enzootic Trypanosoma cruzi transmission and are responsible for human infection (causing Chagas disease) through the Neotropics. Assessing whether individual palm traits (ecological and/or botanical) may increase the risk of palm infestation by triatomines is relevant in areas where bugs invade houses flying from peridomestic palms. We developed a novel fieldwork approach with that objective, and applied it to study infestation by sylvatic Rhodnius ecuadoriensis in 110 tagua palms (Phytelephas aequatorialis). Palm infestation (23% overall) was non-randomly distributed in our sample. Palms located in anthropic landscapes were frequently infested (>27%, n=92), whereas no bugs were collected from palms surveyed within forest remnants (n=18; P=0.01). The presence of abundant decaying vegetable matter (P=0.001) and (to a lesser extent) epiphytic plants (P=0.049) on palm crowns and stems increased the probability of infestation and was positively correlated with the apparent density of bug colonies (R2=0.68). A trend towards higher infestation rates in male palms (34% vs. 18%) could relate to female palm management (removal of infrutescences and vegetable debris) in areas where palm seeds are harvested. An outline of 'risk palm ecotopes' and environmental management-based strategies for the control of peridomestic, palm tree-living vector populations are proposed.

Seroprevalence and risk factors for Trypanosoma cruzi infection in the Amazon region of Ecuador.

Trypanosoma cruzi infection in the Ecuadorian Amazon region has recently been reported. A seroepidemiologic survey conducted in four provinces in this region indicates a seroprevalence rate of 2.4% among the 6,866 samples collected in 162 communities. Among children < OR = 10 years of age, 1.2% were seropositive. Risk factors for T. cruzi seropositivity were having been born and remaining in the Ecuadorian Amazon provinces, age, living in a house with a thatch roof and open or mixed wall construction, recognizing the vector insects, and reporting being bitten by a triatomine bug. These data suggest active transmission of Chagas' disease in the Ecuadorian Amazon region is associated with poor housing conditions, and highlight the need for further studies aimed at understanding the biology of the insect vectors, reservoir species, and the clinical impact of T. cruzi infection as the basis for future educational and control programs in this region.

Biogeography of Triatominae (Hemiptera: Reduviidae) in Ecuador: implications for the design of control strategies.

Chagas disease control strategies strongly depend on the triatomine vector species involved in Trypanosoma cruzi transmission within each area. Here we report the results of the identification of specimens belonging to various species of Triatominae captured in Ecuador (15 species from 17 provinces) and deposited in the entomological collections of the Catholic University of Ecuador (Quito), Instituto Oswaldo Cruz (Brazil), the Natural History Museum London (UK), the London School of Hygiene and Tropical Medicine (UK), the National Institute of Hygiene (Quito), and the Vozandes Hospital (Quito). A critical review of published information and new field records are presented. We analysed these data in relation to the life zones where triatomines occur (11 life zones, excluding those over 2,200 m altitude), and provide biogeographical maps for each species. These records are discussed in terms of epidemiological significance and design of control strategies. Findings relevant to the control of the main vector species are emphasised. Different lines of evidence suggest that Triatoma dimidiata is not native to Ecuador-Peru, and that synanthropic populations of Rhodnius ecuadoriensis in southern Ecuador-northern Peru might be isolated from their sylvatic conspecifics. Local eradication of T. dimidiata and these R. ecuadoriensis populations might therefore be attainable. However, the presence of a wide variety of native species indicates the necessity for a strong longitudinal surveillance system.

[Incidence of acute leukemia in children in Mexico City, from 1982 to 1991]. / Incidencia de las leucemias agudas en niños de la ciudad de México, de 1982 a 1991.

OBJECTIVE: To measure the incidence rate and trend of acute leukemia (AL) in political districts of Mexico City. MATERIAL AND METHODS: Descriptive longitudinal study conducted at six hospitals that care for nearly 97.5% of all cancer cases among children in Mexico City. Study data were collected in 1995 and 1996, and were analyzed in 1999, at the National Medical Center "Siglo XXI" Children's Hospital, of the Mexican Institute for Social Security. Calculations of acute leukemia annual incidence rates, standardized rates, and standardized morbidity rates (SMR) with 95% confidence intervals, were obtained for each district. Morbidity trends were assessed through average change rates. RESULTS: In this study we observed an increasing trend of acute lymphoblastic leukemia (ALL) incidence in five districts: Alvaro Obregon, Cuauhtemoc, Gustavo A. Madero, Iztacalco, and Venustiano Carranza. Acute myeloblastic leukemia (AML) showed no significantly statistic increase of incidence in any district. AML did show a significant SMR in Alvaro Obregon district (SMR = 2.91, 95% CI 1.63-4.80). Higher SMRs were found in the south and southwest areas of the city. CONCLUSIONS: Increasing incidence of ALL was observed in five districts of Mexico City. AML incidence was the highest in Alvaro Obregon district.

[Clinical effect of a sustained-release theophylline formulation in moderate or severe asthmatic patients with intercrisis]. / Efecto clínico de una formulación de teofilina de liberación sostenida en pacientes asmáticos moderados o severos con intercrisis.

The clinical effect of the formulation of theophylline of sustained action was evaluated (Aristegui 300 mg, capsules) to the dose of 9 weight/day mg/kg (every 12 hours) in the consultation of bronchial asthma of Hospital Docente Provincial Clínico Quirúrgico de Santa Clara, in the understood period of February to September of 1997. The time of treatment was of one month and they were carried out five consultations. The sample was constituted by 30 asthmatic, moderate or severe patients. The variables were analyzed: attendance to guard's body, salbutamol use in spray and they were carried out objective mensurations from the lung function to all the patients in the different consultations. With the use of the formulation they diminished the flow expiratory pick significantly, the expiratory volume forced in one second and the flow half expiratory maximum and low incidence of adverse effects existed.

Osteogénesis imperfecta. Experiencia del Hospital Shriners, Unidad Ciudad de México / Osteogenesis imperfecta. Experience in the Shriners Hospital from Mexico City

Desde su primera descripción en 1751, la osteogénesis imperfecta (OI) es una enfermedad de gran interés para el ortopedista; múltiples han sido los médicos e investigadores que han tratado de explicar la etiología, por lo que se han propuesto varias clasificaciones. De 1979 a 1993, se encontraron 57 expedientes de pacientes con OI en nuestro hospital, de los cuales sólo 39 se incluyeron en este estudio. La edad varió desde recién nacidos hasta 16 años, con un promedio de ocho años. Veinte eran del sexo masculino y 19 del femenino. Usando la clasificación de Seedorf encontramos que nueve pacientes eran del tipo I, 17 al tipo II y 3 del tipo III. La presencia de fracturas fue la manifestación clínica más frecuente, siendo el fémur el hueso predominante, con un promedio de 4.4 fracturas por paciente. Dentro del estudio encontramos que la OI tipo tarda gravis es la más frecuente; las deformidades óseas más frecuentes son en las extremidades inferiores: angulación anterolateral del fémur y tibia en sable. Es ideal la correción temprana de las angulaciones óseas, para permitir la deambulación temprana y mediante la ferulización interna prevenir la presentación de nuevas deformidades

[Persistence of critical-reading learning in medical residents]. / Persistencia del aprendizaje de lectura crítica en médicos residentes.

OBJECTIVES: 1. To evaluate the persistence of a training course on critical reading of medical articles by medical residents seven months after training. 2. To compare the persistence of training according to type of training (participative vs expositive). METHODS: We used the same groups of first year medical residents of a previous study. They had received seven months before a 30 hours training in the reading of research articles: Group I (N = 28) had a course of active participation by reading articles previous to meeting discussions; II (n = 17) exposition of research themes by active researchers; III (n = 23) same as II but with non-research trainers. Using an examination questionnaire developed and validated by us to explore critical reading of research papers, the trainees were scored after finishing their training (initial score). Seven months later we retested them using the same test (not all were retested: two were missing in groups I and III and six in Group II). Non parametric statistics were used to compare the groups (Wilcoxon, Kruskal-Wallis, Mann-Whitney). RESULTS: There were no intragroup differences of the retesting versus the initial median in the three groups (I had 17.5 vs 19 initial, II had 7 vs 13, III had 6 vs 3). In the initial testing, Groups I and II scored higher than III, but only Group I was higher than the other groups upon retesting (p < 0.006). CONCLUSION: An active participatory training to promote critical reading was better than the traditional training techniques still widely used.