Intact Short, Intermediate, and Long Skeletal Muscle Fibers Obtained by Enzymatic Dissociation of Six Hindlimb Muscles of Mice: Beyond Flexor Digitorum Brevis.

Skeletal muscle fibers obtained by enzymatic dissociation of mouse muscles are a useful model for physiological experiments. However, most papers deal with the short fibers of the flexor digitorum brevis (FDB), which restrains the scope of results dealing with fiber types, limits the amount of biological material available, and impedes a clear connection between cellular physiological phenomena and previous biochemical and dynamical knowledge obtained in other muscles. This paper describes how to obtain intact fibers from six muscles with different fiber type profiles and lengths. Using C57BL/6 adult mice, we show the muscle dissection and fiber isolation protocol and demonstrate the suitability of the fibers for Ca2+ transient studies and their morphometric characterization. The fiber type composition of the muscles is also presented. When dissociated, all muscles rendered intact, living fibers that contract briskly for more than 24 h. FDB gave short (<1 mm), peroneus digiti quarti (PDQA) and peroneus longus (PL) gave intermediate (1-3 mm), while extensor digitorum longus (EDL), extensor hallucis longus (EHL), and soleus muscles released long (3-6 mm) fibers. When recorded with the fast dye Mag-Fluo-4, Ca2+ transients of PDQA, PL, and EHL fibers showed the fast, narrow kinetics reminiscent of the morphology type II (MT-II), known to correspond to type IIX and IIB fibers. This is consistent with the fact that these muscles have over 90% of type II fibers compared with FDB (~80%) and soleus (~65%). Moving beyond FDB, we demonstrate for the first time the dissociation of several muscles, which render fibers spanning a range of lengths between 1 and 6 mm. These fibers are viable and give fast Ca2+ transients, indicating that the MT-II can be generalized to IIX and IIB fast fibers, regardless of their muscle source. These results increase the availability of models for mature skeletal muscle studies.

Abordajes metodológicos y conceptuales en investigaciones sobre el conflicto armado colombiano y la ruralidad. Un análisis pertinente para la salud pública

Objetivo: Identificar los tipos de estudios realizados sobre el conflicto armado colombiano, sus campos interdisciplinares, métodos y técnicas, así como las concepciones acerca de conflicto armado y ruralidad utilizados en los mismos, y su pertinencia para la salud pública. Metodología: En esta investigación, de índole cualitativa y metateórica, se efectuó una revisión narrativa, para lo cual se empleó un protocolo de búsqueda de artículos, con criterios de inclusión y exclusión. Se incluyeron artículos y trabajos de investigación existentes en bases de datos y repositorios institucionales, los cuales fueron sometidos a análisis de contenido. Resultados: En su mayoría, los estudios analizados provienen de repositorios institucionales universitarios y, en términos disciplinares, surge de las ciencias sociales, humanas y políticas. Por consiguiente, los métodos investigativos utilizados son mayormente los acuñados en dichas disciplinas, como el etnográfico y las historias de vida, aunque se presentan métodos correlacionales y experimentales. Pocos trabajos utilizan referentes conceptuales o teóricos explícitos sobre el conflicto armado y la ruralidad, lo que genera inquietudes académicas, éticas y políticas respecto a las formas en que se comprenden y abordan las realidades en estos temas. De 101 trabajos analizados, solo 7 pertenecen el campo de la salud, y de estos, únicamente 1 al campo de la salud pública. Este hallazgo resulta notable, dados los múltiples efectos que ha generado el conflicto sobre la salud y la vida de diferentes grupos de la población colombiana. Conclusión: Los efectos de la violencia, las guerras, los conflictos y sus efectos sobre la salud poblacional han sido objeto de interés de organismos internacionales y nacionales, y de algunos académicos del campo de la salud pública. Se hace necesario un mayor protagonismo de la salud pública frente a los efectos del conflicto colombiano sobre la población.

Objective: To identify the types of studies conducted on the Colombian armed conflict, their interdisciplinary fields, methods, techniques, as well as the conceptions of armed conflict and rurality used in these studies and their relevance for public health. Methodology: In this qualitative and meta-theoretical study, we conducted a narrative review, which involved using a search protocol for selecting papers following inclusion and exclusion criteria. We included articles and research papers subjected to content analysis that were found in institutional repositories and databases. Results: Most of the analyzed studies are from university institutional repositories and, in disciplinary terms, from social, human, and political sciences. Thus, the research methods that are used are primarily those coined in these fields, such as the ethnographic and life stories methods, although correlational and experimental methods are also included. Few works use explicit conceptual or theoretical references to armed conflict and rurality. This generates academic, ethical, and political concerns regarding how the realities of these issues are understood and addressed. Of the 101 papers we analyzed, only 7 belong to the field of healthcare, and of these, only 1 belongs to the field of public health. This finding is noteworthy, given the multiple effects that the conflict has had on the health and lives of various groups of the Colombian population. Conclusion: The effects of violence, wars, conflicts, and their effects on population health have been the subject of interest of international and national bodies and of some academics in the field of public health. There is a need for a stronger role of public health in addressing the effects of the Colombian conflict on the population.

Objetivo: Identificar os tipos de estudos realizados sobre o conflito armado colombiano, seus campos interdisciplinares, métodos e técnicas, assim como as concepções sobre o conflito armado e a ruralidade neles utilizados e sua pertinência para a saúde pública. Metodologia: Nesta pesquisa, qualitativa e metateórica, foi realizada uma revisão narrativa, em que se empregou um protocolo de busca de artigos, com critérios de inclusão e exclusão. Incluíram-se artigos e trabalhos de pesquisa existentes em bases de dados e repositorios institucionais, que foram submetidos a análise de conteúdo. Resultados: Em sua maioria, os estudos analisados provêm de repositórios institucionais universitários e, em termos disciplinares, surge das ciências sociais, humanas e políticas. Por conseguinte, os métodos de pesquisa usados são mormente os próprios dessas disciplinas, como o etnográfico e as historias de vida, mesmo que apresentem métodos correlacionais e experimentais. Poucos trabalhos usam referentes conceptuais ou teóricos explícitos sobre o conflito e a ruralidade, o que gera inquietudes acadêmicas, éticas e políticas ao redor das formas em que se compreendem e abordam as realidades nesses temas. De 101 trabalhos analisados apenas 7 pertencem ao campo da saúde, e desses, unicamente 1 ao campo da saúde pública. Esse achado resulta notável, por causa dos efeitos que o conflito tem gerado na saúde e na vida de diferentes grupos da população colombiana. Conclusão: Os efeitos da violência, as guerras, os conflitos e seus efeitos na saúde populacional tem sido objeto de interesse de organismos internacionais e nacionais, e de alguns acadêmicos do campo da saúde pública. É necessário um maior protagonismo da saúde pública perante os efeitos do conflito colombiano na população.

Time and gender measurement invariance in the modified Calderon depression scale.

BACKGROUND: Assessing change and comparing groups requires high quality and invariant scales. However, there is limited evidence of simultaneous longitudinal and gender measurement invariance for depression scales. This evidence is even more scant with long-established panel studies from low and middle-income countries. METHODS: In this paper, we used three waves (years 2002, 2005, and 2009) of a nationally representative panel study to examine the psychometric properties of the modified Calderon Depression Scale (CAL-DM)-a one-item exclusion of a depression scale designed for a population residing in a middle-income country (i.e., Mexico). Our analytical sample included 16,868 participants: 7,696 men and 9,172 women. Using Confirmatory Factor Analysis (CFA), we first examined overall fit in each wave, and then we tested time, gender, and time-gender measurement invariance across three waves. We also estimated and compared depression score means by gender and time. Finally, we examined the association between depression scores and self-rated health. RESULTS: Our analyses indicated the CAL-DM is a robust scale, suitable for time, gender, and time by gender comparisons. Mean comparisons exemplified how the scale can be used as a latent variable or a summative score. Women have higher depression scores than men and the gap is narrowing from 3.4 in 2002 to 2.5 in 2009. CONCLUSIONS: The CAL-DM is a reliable instrument to measure depression in the Mexican general population that can be used for epidemiological research. Our results will contribute to a burgeoning line of research that examines the social determinants of depression, and the risk factors associated with different individuals' depression trajectories over the life course.

Offspring Migration and Parents' Emotional and Psychological Well-being in Mexico.

In Mexico, offspring migration disrupts familial norms of coresidence and geographic proximity. This paper examines how offspring migration, both domestically and to the United States, affects the emotional and psychological well-being of parents who remain in the place of origin. Using nationally-representative longitudinal data from the Mexican Family Life Survey (N=4,718), we found limited evidence that parents whose offspring emigrated to the United States experience worse outcomes than parents of offspring who do not migrate. Although we found that offspring U.S. migration was not associated with changes in parents' overall depressive syndrome, a child's U.S. migration increased the likelihood of experiencing loneliness, and lead to a lower likelihood of recovery from parental sadness over time. Children's domestic migration did not affect parental well-being. These findings add to a growing body of literature that should be considered when assessing the broader impact of migration on family members who remain behind.

Return Migration to Mexico: Does Health Matter?

We use data from three rounds of the Mexican Family Life Survey to examine whether migrants in the United States returning to Mexico in the period 2005-2012 have worse health than those remaining in the United States. Despite extensive interest by demographers in health-related selection, this has been a neglected area of study in the literature on U.S.-Mexico migration, and the few results to date have been contradictory and inconclusive. Using five self-reported health variables collected while migrants resided in the United States and subsequent migration history, we find direct evidence of higher probabilities of return migration for Mexican migrants in poor health as well as lower probabilities of return for migrants with improving health. These findings are robust to the inclusion of potential confounders reflecting the migrants' demographic characteristics, economic situation, family ties, and origin and destination characteristics. We anticipate that in the coming decade, health may become an even more salient issue in migrants' decisions about returning to Mexico, given the recent expansion in access to health insurance in Mexico.