Abstract. The present article seeks to re-asses the intellectual inspiration behind Vladimir Lenin’s “Imperialism, the Highest Stage of Capitalism” (1917). This is important not only because it allows us to determine the originality of Lenin’s ideas on imperialism, but also because it can spark more interest in the work of other intellectuals who wrote on this, work which, in some cases, has been neglected. Through a historical and ideational analysis of Lenin’s five characteristics of the imperialism of the early 20th century, the present study reveals some of the thinkers who provided a solid intellectual basis to Lenin’s text. It is concluded that, even though Lenin’s pamphlet has left an important legacy, it is mainly a synthesis of the vast previous work of primarily socialist intellectuals living in the early 20th century.

Resumen. El presente artículo busca revaluar una buena parte de la inspiración intelectual detrás del famoso panfleto de Vladimir Lenin “El Imperialismo, fase superior del capitalismo” (1917). Esto es importante no solo porque nos permite establecer la originalidad de las ideas de Lenin respecto al tema del imperialismo, sino también porque puede despertar un mayor interés en el trabajo de otros intelectuales que escribieron al respecto y que, en algunos casos, es ignorado. A través de un análisis histórico ideacional de las cinco características del imperialismo de principios del siglo XX que Lenin estipuló, el presente estudio revela algunos de los pensadores que brindaron una base intelectual sólida al texto de Lenin. Se concluye que, pese a que dejó un legado importante, el panfleto en cuestión es principalmente una síntesis del vasto trabajo previo realizado primordialmente por intelectuales de corte socialista de principios del siglo XX.

RESUMO Nos últimos anos, trabalhos de cunho historiográfico em torno de fontes e arquivos de arquitetura e urbanismo, assim como iniciativas institucionais e particulares ligadas a questões de preservação, vêm contribuindo para a consolidação de uma agenda coletiva em torno do valor histórico desses acervos no Brasil. Os debates giram em torno de seu papel no interior de instituições culturais, acadêmicas e profissionais, e de sua relevância para a formação, a memória e a prática em arquitetura e urbanismo. Nossa intenção aqui é justamente discutir o papel, a agência e as potencialidades desses acervos de arquitetura nas atividades de ensino e pesquisa na área. Inicialmente, apresentamos um quadro geral de alguns acervos de arquitetura no Brasil e suas relações institucionais e com experiências de ensino específicas. Em seguida, refletimos sobre usos pedagógicos recentes desses acervos, destacando algumas experiências didáticas nacionais e estrangeiras. Por fim, discutimos a importância dos acervos especializados para a pesquisa na área, seus significados, possibilidades e dilemas contemporâneos. Desse modo, pretendemos contribuir para a definição de estratégias ligadas à constituição, à preservação e ao uso de acervos de arquitetura e urbanismo no interior de instituições acadêmicas no país.

ABSTRACT In recent years, historiographical works on architectural and planning sources or archives, as well as institutional or private initiatives aimed at preservation issues, have helped to consolidate a collective agenda around the historical value of these collections in Brazil. Debates revolve around their role within cultural, academic, and professional institutions, and their relevance to education, memory, and practice in architecture and urbanism. This article aims to speculate about the roles, agencies, powers, and limits of architectural collections in contemporary teaching and research practices. To this end, it first presents an outlook of architectural collections in Brazil and their relations with different academic institutions. Then, the text will comment on recent pedagogical uses of architectural and planning collections, highlighting some teaching experiences in both the national and international context. Finally, it discusses the importance of specialized collections to research in the field of architecture and urban planning, as well as their contemporary meanings, possibilities, and dilemmas. This study is expected to contribute to the definition of strategies on the constitution, preservation, and use of architectural and planning collections within academic institutions in Brazil.

Abstract Data on the implication of the stable fly (Stomoxys calcitrans, Diptera: Muscidae), in the transmission of Anaplasma marginale in tick-free cattle is scarce. Hence, the objective of this investigation was to detect the presence of DNA from A. marginale in stable flies caught near a bovine herd, which has been maintained free of ticks for 40 years, and occasionally presents some clinical cases of anaplasmosis. Twenty-four batches of S. calcitrans (15 flies each) were collected in the morning and in the afternoon twice a week (except for one catch in one week of September and one catch in one week of December) during 12 catching days in a period of four months. Their DNA was obtained and analysed by nested PCR (nPCR) to identify the presence of A. marginale DNA. Seven of the batches (29.16 %) were positive for A. marginale, as detected by an nPCR that targets the A. marginale msp5 gene. Similarly, in two out of 12 catching days (16.66 %), those S. calcitrans batches collected in the morning and in the afternoon, were positive for A. marginale, while those S. calcitrans groups collected in three out of 12 catching days (25 %), were positive for the rickettsia. The obtained results suggest that A. marginale transmission is carried out mechanically by S. calcitrans, favouring the circulation and maintenance of the microorganism in this particular bovine herd.

Introduction: Severe traumatic brain injury (TBI) is a serious condition. Intracranial pressure (ICP) monitoring can be used to direct treatment, which is of limited access in developing countries. Objective: To describe the clinical experience of pediatric patients with severe TBI. Patients and Method: A clinical experience in patients with severe TBI was conducted. Age was 1-17 years, exclusion criteria were chronic illness and psicomotor retardation. Informed consent was obtained in each case. Two groups were formed based on the criterion of neurosurgeons: with and without intracraneal pressure (ICP) monitoring. PIC monitoring was performed through a 3PN Spiegelberg catheter and a Spiegelberg HDM 26 monitor. Patients were treated according international pediatric guides. The characteristics of both groups are described at 6 months of follow-up. Results: Forty-two patients (CM=14 and SM=28). Those in the CM Group had lower Glasgow coma scale score and Marshall classification with poorer prognosis. Among them survival rate was lower, although the outcome was from moderate to good. No complications were reported with the use of the ICP catheter. Conclusion: Patients with ICP monitoring had greater severity at admission and an increased mortality; however, the outcome for the survivors was from moderate to good. It is necessary to conduct randomized clinical trials to define the impact of ICP monitoring on survival and quality of life in severe TBI patients.

Introducción: El traumatismo craneoencefálico severo (TCES) es una entidad grave. La monitorización de la presión intracraneal (PIC) permite dirigir el tratamiento, el cual es de limitado acceso en países en vías de desarrollo. Objetivo: Describir la experiencia clínica de pacientes pediátricos con TCES. Pacientes y método: Se incluyeron pacientes con TCES, edad entre 1 y 17 años, previo consentimiento informado de los padres y/o tutores. Se excluyeron pacientes con enfermedades crónicas o retraso psicomotor. Los pacientes ingresaron desde el Servicio de Urgencia, donde se les realizó scanner cerebral (TAC), clasificándose las lesiones por Escala de Marshall. Los pacientes fueron divididos en 2 grupos según criterio neuroquirúrgico: con monitorización (CM) y sin monitorización (SM) de presión intracraneana. La monitorización de la PIC se realizó a través de un catéter intraparenquimatoso 3PN Spiegelberg conectado a un monitor Spiegelberg HDM 26. Los pacientes fueron tratados de acuerdo a las guías pediátricas para TCES. Se consideró la supervivencia como los días transcurridos entre el ingreso hospitalario y el fallecimiento, o su evaluación por Escala de Glasgow para un seguimiento de 6 meses. Resultados: Cuarenta y dos pacientes (CM = 14 y SM= 28). Aquellos con monitorización tenían menor puntuación de la escala de coma de Glasgow y clasificación de Marshall con peor pronóstico. En ellos la supervivencia fue menor y el resultado moderado a bueno. No se registraron complicaciones con el uso del catéter de PIC. Conclusión: Pacientes con monitorización tuvieron mayor gravedad al ingreso y una mayor mortalidad; sin embargo, el resultado funcional de los sobrevivientes fue de moderado a bueno. Se requiere de la realización de ensayos clínicos aleatorizados para definir el impacto de la monitorización de la PIC en la supervivencia y calidad de vida en estos pacientes.

Los cangrejos Brachyura son especies iteróparas, que presentan alta diversificación en los patrones de reproducción, que pueden haber evolucionado como una respuesta específica de la especie a las condiciones ambientales. Las especies tropicales frecuentemente presentan una reproducción en todo el año debido a las condiciones estables del medio. El cangrejo Goniopsis cruentata es una especie ampliamente distribuida en largo del Atlántico occidental, y que habita prácticamente cada micro-hábitat en el ecosistema de manglar. El objetivo del presente estudio fue evaluar el periodo de reproducción del cangrejo G. cruentata en el noreste de Brasil. Un total de 71 hembras ovadas, fueron capturadas entre agosto 2007 y julio 2008, y utilizadas para obtener el periodo de reproducción de esta especie. Nuestra hipótesis es que, ya que las zonas tropicales no presentan gran variación de las temperaturas, las oscilaciones temporales de la salinidad son el principal factor que influye en la actividad reproductiva de G. cruentata. Se analizó el período reproductivo mediante la proporción mensual de hembras ovadas. Una correlación fue aplicada para evaluar la influencia de los factores abióticos limitantes (salinidad, pluviosidad, temperatura del aire y del agua) en la época de crianza. La población se reproduce continuamente con picos estacionales en el período seco, lo que no fue asociado a las variaciones mensuales de salinidad, precipitación y temperatura del aire y del agua. Por lo tanto, nuestra hipótesis fue refutada. Sin embargo, la reproducción se intensificó en el período seco, cuando la salinidad y las temperaturas fueron más altas y la precipitación fue menor. Se concluye que, a pesar de que la reproducción no está relacionada con la variación mensual de los factores ambientales limitantes, ella ocurre en períodos de mayor salinidad y temperatura, y baja precipitación.

The brachyuran crabs are iteroparous species which present a high diversification of reproduction patterns, which may have evolved as a species-specific response to environmental conditions. Tropical species commonly present a year-round reproduction due to stable environment conditions. Goniopsis cruentata is a crab species widely distributed along the Western Atlantic, inhabiting practically every microhabitat in the mangrove ecosystem. The aim of the present study is to determine the breeding period of the crab Goniopsis cruentata in Northeastern Brazil and also to evaluate the influence of water salinity, rainfall and air and water temperature on it. A total of 71 ovigerous females, captured from August-2007 to July-2008, were used to assess the breeding period of this species. It was analyzed by the monthly proportion of ovigerous females. A correlation was applied to verify the influence of the abiotic factors on the breeding period. The present population bred seasonal-continuously with peaks in the dry period, which was not associated with monthly variations of salinity, rainfall and air and water temperatures. Therefore, according to statistical analyses, our hypothesis was refuted. However, breeding was intensified in the dry period, when salinity and temperatures were higher and rainfall was lower. We conclude that, even though breeding is not related to monthly variation of environmental factors, it occurs in periods of higher salinity and temperatures and lower rainfall.

PROBLEM: During an influenza outbreak or pandemic, timely access to antivirals is essential to reduce disease severity and transmission. Best practices in antiviral procurement, storage, distribution, prescription and dispensing must be followed for prompt drug delivery. APPROACH: Mexico implemented a national pandemic preparedness plan in 2006 and created a strategic antiviral stockpile. Oseltamivir powder was stored centrally in bulk for distribution to all 31 states and the capital district during an influenza outbreak. LOCAL SETTING: San Luis Potosí, in northern Mexico, was one of the states most intensely affected by the 2009 H1N1 influenza outbreak. RELEVANT CHANGES: The oseltamivir powder was meant to be reconstituted locally but had to be reconstituted centrally during the 2009 influenza outbreak. Doubts arose surrounding the shelf-life of the reconstituted product. As a result of these problems, the first supply of the drug reached San Luis Potosí 11 days after the influenza outbreak had begun. Furthermore, dispensing criteria at the state level had to be changed in conformity with the availability of oseltamivir. LESSONS LEARNT: Antiviral demand forecasts should be based on clearly defined distribution and dispensing criteria and decentralization of some of the medication stockpile should be considered. Mexico's national pandemic preparedness plan needs to be updated in accordance with the lessons learnt in 2009 to improve strategic stockpile management and ensure rapid delivery of oseltamivir to the population.

SITUACIÓN: Durante un brote o pandemia de gripe, el acceso a tiempo a antivíricos es esencial para reducir la severidad y la transmisión de la enfermedad. Han de seguirse las mejores prácticas en el aprovisionamiento, almacenamiento, distribución, prescripción y dispensación para proporcionar a tiempo los medicamentos. ENFOQUE: México implementó un plan de preparación ante la pandemia en 2006 y creó unas reservas estratégicas de antivíricos.l Oseltamivir en polvo fue almacenado en bruto de forma centralizada para su distribución a los 31 estados y el distrito de la capital durante un brote de gripe. MARCO REGIONAL: San Luis Potosí, en el norte de México, fue uno de los estados más intensamente afectados por el brote de gripe H1N1 de 2009. CAMBIOS IMPORTANTES: Se esperaba que oseltamivir en polvo fuese reconstituido localmente, pero tuvo que ser reconstituido de forma centralizada durante el brote de gripe de 2009. Aparecieron dudas sobre la vida útil del producto reconstituido. Como resultado de estos problemas, el primer suministro de medicamento llegó a San Luis Potosí 11 días después del comienzo del brote de gripe. Además, a nivel estatal los criterios de dispensación tuvieron que cambiarse de acuerdo con la disponibilidad de oseltamivir. LECCIONES APRENDIDAS: Las predicciones de demanda antiviral han de estar basadas en criterios claramente definidos de distribución y dispensación, y ha de tenerse en cuenta la descentralización de parte de las existencias del medicamento. El plan nacional de preparación ante la pandemia de México ha de ser actualizado de acuerdo con las lecciones aprendidas en 2009 para mejorar la gestión estratégica de existencias y asegurar la rápida provisión de oseltamivir a la población.

PROBLÈME: Lors d'une épidémie ou pandémie de grippe, un accès en temps opportun aux antiviraux est essentiel pour atténuer la gravité et réduire la transmission de la maladie. Il convient de suivre les meilleures pratiques en matière d'approvisionnement, de stockage, de distribution, de prescription et d'administration si l'on veut assurer une délivrance du médicament la plus rapide possible. APPROCHE: Le Mexique a mis en place en 2006 un plan national de préparation en cas de pandémie et a créé une réserve antivirale stratégique. Un stock d'oseltamivir en poudre était centralisé pour une distribution à l'ensemble des 31 états et à la capitale en cas d'épidémie de grippe. ENVIRONNEMENT LOCAL: San Luis Potosí, dans le nord du Mexique, figurait parmi les états les plus durement touchés par l'épidémie de grippe H1N1 de 2009. CHANGEMENTS SIGNIFICATIFS: L'oseltamivir en poudre était supposé être reconstitué localement, mais il a toutefois dû l'être de manière centralisée lors de l'épidémie de grippe de 2009. Des doutes ont commencé à se poser quant à la durée de conservation du produit reconstitué. Suite à ces difficultés, San Luis Potosí n'a reçu sa première livraison du médicament que 11 jours après le début de l'épidémie de grippe. En outre, les critères de cet état en termes d'administration ont dû être modifiés selon la disponibilité de l'oseltamivir. LEçONS TIRÉES: Les prévisions relatives à la demande de médicaments antiviraux devraient se baser sur des critères de distribution et d'administration clairement définis. Il faut également envisager la décentralisation de certaines réserves de médicaments. Le plan national mexicain de préparation aux pandémies doit être révisé en fonction des leçons apprises en 2009 afin d'améliorer la gestion stratégique des stocks et de permettre la livraison d'oseltamivir à la population dans les meilleurs délais.

O fator de condição é um parâmetro que age como um indicador geral do "bem-estar" de uma espécie e pode ser obtido através da análise da relação largura-peso. O presente trabalho visa investigar a relação tamanho vs. peso e o fator de condição do caranguejo Goniopsis cruentata (Latreille, 1803). A área de estudo foi o complexo estuarino Mundaú/Manguaba, Maceió, estado de Alagoas, Nordeste do Brasil. As amostragens foram realizadas mensalmente de agosto de 2007 a julho de 2008. Um total de 626 indivíduos foi analisado, sendo 309 machos e 317 fêmeas. Os machos foram maiores e mais pesados que as fêmeas, o que é esperado em muitas espécies de braquiúros. O crescimento foi alométrico positivo tanto para machos (b = 3,42) quanto para fêmeas (b = 3,30), não obedecendo a "regra do cubo". O fator de condição da fêmea foi maior do que o dos machos, provavelmente devido ao peso das gônadas das fêmeas. O fator de condição também variou sazonalmente para ambos os sexos, sendo mais elevado no outono e no inverno nos machos, e no outono e primavera nas fêmeas, e estando relacionado à muda e ao período intenso de desova.

The condition factor is a parameter which acts as a general indicator of the "well-being" of a species, and it can be obtained through the analysis of width vs. weight relationships. The present work aims to investigate size vs. weight relationship and the condition factor of the crab Goniopsis cruentata (Latreille, 1803). The study area was the Mundaú/Manguaba estuarine complex, Maceió, state of Alagoas, Northeast Brazil. Samplings were monthly accomplished from August 2007 to July 2008. A total of 626 individuals were analyzed, being 309 males and 317 females. Males were larger and heavier than females, what is expected in many brachyuran. The growth was positive allometric to both males (b = 3.42) and females (b = 3.30), not obeying the "cube law". The condition factor of female was higher than that of male crabs, probably due to the gonad weight of females. It also varied seasonally for both sexes, being higher in the autumn and winter in males, and in the autumn and spring in females, and related to the molt and period of spawning intensification.

The present work aims to study the size vs. weight relationship and the condition factor of a commercially important crab, Callinectes danae, from an estuarine complex located at Pernambuco State, Northeastern Brazil. After sampled, the specimens were measured on their carapace width (CW; mm) and weighted on their wet weight (WW; g). A total of 1,635individuals of C. danae were analyzed, being 881 males (53.8%) and 754 females (46.2%). Males were significantly larger and heavier than females (p < 0.05), the expected pattern to many crabs. The relationship WW vs. CW, described through the potency equation, was allometrically positive for both males (b = 3.12) and females (b = 3.02), a result also observed in other swimming crabs. The mean condition factor of males was 8.0 10-5 ± 1.5 10-5, and that of females was 11.5 10-5 ± 2.8 10-5, being significantly higher in females (p < 0.05), due to the fact that female gonads are heavier than that of males. The condition factor oscillated throughout the sampling year, for both sexes, which was related to the reproductive cycle.

A obra de Gregori Warchavchik (1896-1972) vem sendo tratada como um esboço de renovação, isolado e ambíguo, sem conseqüências sobre os rumos da moderna arquitetura brasileira. Não é de estranhar que até hoje o arquiteto não tenha merecido um exame minucioso de sua trajetória. Este artigo se detém nos anos de formação do arquiteto russo, na tentativa de melhor situá-lo na história do modernismo brasileiro e do modernismo arquitetônico em particular.

Gregori Warchavchik's work has been regarded as an isolated effort of renewal, a piece of minor impact to Brazilian modern architecture. It's no surprise, thus, that hitherto the trajectory of the Russian architect hasn't been studied carefully. This article, focused on his formative years, is an attempt to better situate his importance for Brazilian modernism.

Na literatura de viagem, dois gêneros tradicionais se destacam: o diário e o guia; e dois personagens: o viajante e o cicerone. O objetivo deste artigo é avançar na compreensão das cidades como campo cultural na perspectiva da viagem e dos viajantes. Para tal, proponho repensar a distância entre Mário de Andrade e Gilberto Freyre, figuras centrais do modernismo e da antropologia no Brasil, a partir do exame de suas experiências de viagem. Mais especificamente, trata-se de encenar um encontro entre estas personalidades diversas, às vezes antagônicas, em um topos comum de acesso à cultura brasileira: as cidades do Norte e do Nordeste do Brasil, surpreendidas na crise do regime agro-exportador e patriarcal, com seus resíduos de paisagem e caráter, povo e modos de vida, memória, forma urbana, arquitetura, arte e folclore. A base de leitura são os diários e crônicas redigidos pelo escritor paulistano ao longo de suas duas longas viagens etnográficas à Amazônia (1927) e ao Nordeste (1928/1929); o diário de juventude, as crônicas de jornal e o Guia Prático, Histórico e Sentimental da Cidade do Recife (1934), do antropólogo pernambucano. Se a opção por estes escritos - menores no conjunto de suas obras, é verdade, porém sólidas posições nos gêneros em que se incluem - instiga o turista e o cicerone a uma relação de proximidade, neles é possível flagrar, ao lado da viagem prazerosa, uma dimensão exploratória e etnográfica da sociedade moderna.

In the literature of travel, two traditional orders come up, the journal and the guide, as well as two characters, the traveler and the cicerone. The objective of this article is to advance in the comprehension of cities as some cultural field on the perspective of both the travel and the travelers. In order to do so, I propose the rethinking of the distance between Mário de Andrade and Gilberto Freyre, central figures of Brazilian modernism and anthropology, by examining their travel experiences. More specifically we show a meeting between these two diverse personalities, sometimes antagonistic, in a common topos to access the Brazilian culture: Northern and Northeastern Brazilian cities caught in the crisis of the agro-exporting and patriarchal regimes with their remains of landscape and character, peoples and ways of life, memories, urban setup, architecture, folklore, art. The reading bases are the journals and chronicles written by the writer from São Paulo state along his two long ethnographical journeys to the Amazonian (1927) and to the Northeastern (1928/1929) regions as well as youth journals, newspaper chronicles, and the Guia Prático, Histórico e Sentimental da Cidade do Recife (1934) - "Practical, Historical, and Sentimental Guide of the City of Recife (1934)," by the anthropologist from Pernambuco state. If the option for such writings - less important in their authorship but constituting solid positions in the genre - instigates the tourist and the cicerone towards a relation of proximity, it is possible to take a snapshot of, together with the pleasurable travel, an exploratory and ethnographic dimension of the modern society.

Dans la littérature à propos des voyages, deux genres traditionnels apparaissent : le journal de bord et le guide ; et deux personnages : le voyageur et le cicérone. L'objectif de cet article et d'avancer dans la compréhension des villes en tant que champ culturel dans la perspective du voyage et des voyageurs. Dans cet article, nous proposons de repenser la distance entre Mário de Andrade et Gilberto Freyre, figures centrales du modernisme et de l'anthropologie au Brésil, à partir de l'examen de leurs expériences de voyage. Plus spécifiquement, il s'agit de mettre en scène une rencontre entre ces deux personnalités distinctes, parfois antagonistes, en un topos commun d'accès à la culture brésilienne: les villes du Nord et du Nordeste du Brésil, surprises par la crise du régime agro-exportateur et patriarcal, avec leurs résidus de paysage et de caractère, de peuple et de modes de vie, de mémoire, de forme urbaine, d'architecture, d'art et de folklore. La base de lecture sont les journaux de bord et les chroniques rédigées par l'écrivain paulista tout au long de ses deux longs voyages ethnographiques en Amazonie (1927) et au Nordeste (1928/1929); le journal de jeunesse, les chroniques de journal et le Guide Pratique, Historique et Sentimental de la Ville de Recife (1934), de l'anthropologue originaire du Pernanbouc. Si l'option pour ces écrits - d'importance mineure dans l'ensemble de leurs œuvres, mais qui constituent, néanmoins de solides positions par rapport aux genres dans lesquels ils s'incluent - instiguent le touriste et le cicérone à une relation de proximité, il est possible de constater, à côté d'un voyage plaisant, une dimension exploratrice et ethnographique de la société moderne.

Myofibroblasts are a fibroblast subpopulation with a phenotype similar to smooth muscle cells, since they express the cytoskeletal a-smooth muscle actin (α-SMA); however, in different organs, they show some phenotypical differences. Their physiology is similar in the different tissues and organs. Based on their extensive spectrum of synthesis and secretion of molecules such as cytokines, interleukins, chemokines, growth factors, lipids, diverse physiological mediators, molecules of the extracelullar matrix, MMPs and TIMPs, they play a very important role during embryogenesis, organogenesis, inflammation, repair and wound healing, besides being fundamental in the processes of regeneration and repair (fibrosis) that occur in the different organs. In the case of the respiratory system, the myofibroblasts are as important in the air ways as in the lung, mainly participating in the diverse pathogenic processes; whether in pathologies with a derivative pattern such as emphysema, or in diseases with a fibrogenic pattern with excessive synthesis of the diverse components of the extracellular matrix, as occurs in pulmonary fibrosis and asthma. Myofibroblasts are especially important in the different forms of pulmonary fibrosis whether idiopathic or of known cause. Idiopathic fibrosis, as asthma, seems to be essentially restricted to areas of tissue adjacent to damaged alveolar-epithelial areas, where a physiopathogenic relation of type II neumocyte-myofibroblast-fibroblast exists. On the other hand, myofibroblasts are mostly derived from fibroblast transdifferentiation by TGF-β1 stimulation.

Los miofibroblastos representan una subpoblación de fibroblastos con un fenotipo similar al de las células del músculo liso, debido a que expresan a-actina de músculo liso en su citoesqueleto, aunque también como subpoblación exhiben diferencias fenotípicas entre sí en diferentes órganos, su fisiología es semejante en los diferentes tejidos y órganos en que se encuentren. Con base en su amplio espectro de síntesis y secreción de moléculas, tales como citocinas, interleucinas, quimiocinas, factores del crecimiento, lípidos, diversos mediadores fisiológicos, moléculas de la matriz extracelular, MMPs y TIMPs, desempeñan una participación muy importante durante la embriogénesis, organogénesis, inflamación, reparación y cicatrización, siendo además fundamentales en los diferentes procesos de regeneración y reparación (fibrosis) que ocurren en los distintos órganos. En el caso del sistema respiratorio, los miofibroblastos son importantes, tanto en las vías aéreas como en el pulmón, participando fundamentalmente en los diversos procesos patogénicos, ya sea en enfermedades con un patrón degradativo como el enfisema, o bien, con un patrón reparativo con depósito excesivo de los diversos componentes de la matriz extracelular, tal como ocurre en la fibrosis pulmonar y el asma. Son especialmente importantes en las diferentes formas de fibrosis pulmonar ya sea de causa conocida o idiopática. Esta última, a semejanza del asma, parece restringirse fundamentalmente a zonas del tejido adyacente a epitelios alveolares dañado, donde se da una relación fisiopatogénica neumocito tipo II-miofibroblasto-fibroblasto. Los miofibroblastos se originan principalmente por transdiferenciación de fibroblastos y principalmente por estimulación del TGF-β1.