Analysis of the Pediatric Radiotherapy Landscape in Mexico and a Subsequent Educational e-Contouring Intervention.

PURPOSE: Mexico and Central America have the highest childhood cancer incidence in the West. Pediatric-specific oncology knowledge contributes to the disparity. We sought to (1) determine the self-identified treatment patterns and needs of Mexican pediatric radiation oncologists and (2) pilot a workshop to improve contouring accuracy. MATERIALS AND METHODS: Partnering with local experts and the Sociedad Mexicana de Radioterapeutas (SOMERA), a 35-question survey was designed to ascertain pediatric radiotherapy capacity and distributed through the SOMERA listserv. The most challenging malignancies were selected for workshop. Participants received precontouring and postcontouring homework to assess improvement per the Dice metric. The Wilcoxon sign-rank test was used for comparative statistics. RESULTS: Ninety-four radiation oncologists attempted and 79 completed the survey. Forty-four (76%) felt comfortable treating a pediatric patient, and 36 (62%) were familiar with national protocols for pediatric treatment. Most had access to nutrition, rehabilitation, endocrinology, and anesthesia; 14% had access to fertility services and 27% to neurocognitive support; 11% noted no support, and only one respondent had child-life support. The postsurvey contouring workshop was conducted for high-grade glioma, medulloblastoma, and Hodgkin lymphoma. Significant improvements were seen in all target volumes. CONCLUSION: We present the first national survey of Mexico's pediatric radiotherapy capacity and Latin American e-contouring educational intervention with preworkshop and postworkshop Dice metrics, noting statistically significant improvement in all target volumes. Participation improved compared with prior experience through SOMERA partnership and Continuing Medical Education incentivization.

Cross-Sectional International Survey to Determine the Educational Interests of Spanish-Speaking Latin American Radiation Oncologists.

PURPOSE: With the existing oncology disparities in Latin America, physician expertise has been cited as a possible contributor to inferior oncologic outcomes in some cancers. As two-dimensional radiotherapy rapidly evolved to intensity-modulated radiation therapy in Latin America, adequate contouring education is an actionable target to improving physician knowledge and clinical outcomes. Yet, topics of interest to Latin American radiation oncologists are underreported. We assessed Latin American interest in a virtual platform for case discussion and identified the educational topics of most interest to them. MATERIALS AND METHODS: A Spanish-language online survey was designed by a team of Latin American educators. The questions assessed professional nationality, desire for an online educational platform for case presentation, career length, and topics of interest. Educational topics included head and neck (H&N), CNS, GI, lung, gynecologic, breast, and pediatric cancers, lymphoma, sarcoma, stereotactic body radiotherapy (SBRT), brachytherapy, and medical physics. RESULTS: One hundred thirty-three surveys were included for analysis. Overall, 127 respondents (98%) affirmed interest in participating in a virtual platform for case discussion and treatment advances. The most popular educational themes were H&N cancers (24%), SBRT (14%), and CNS cancers (13%). Of countries with > 10 respondents, the most popular educational topic remained H&N cancers for Argentina, Chile, and Mexico, but the most popular topic among Peruvian respondents was CNS cancer (27%). CONCLUSION: With international collaboration and a large sample size, we present the first survey results describing Latin American radiation oncology educational interests. Participants were overwhelmingly interested in a virtual platform, and most were specifically interested in H&N cancer education. These results can be used for focused didactic preparation in Latin America. Future efforts should expand on improving representation and outreach among Central American radiation oncologists.

Fifty Years of Mountain Passes: A Perspective on Dan Janzen's Classic Article.

In 1967, Dan Janzen published "Why Mountain Passes Are Higher in the Tropics" in The American Naturalist. Janzen's seminal article has captured the attention of generations of biologists and continues to inspire theoretical and empirical work. The underlying assumptions and derived predictions are broadly synthetic and widely applicable. Consequently, Janzen's "seasonality hypothesis" has proven relevant to physiology, climate change, ecology, and evolution. To celebrate the fiftieth anniversary of this highly influential article, we highlight the past, present, and future of this work and include a unique historical perspective from Janzen himself.

A Few Meters Matter: Local Habitats Drive Reproductive Cycles in a Tropical Lizard.

Reproductive phenology often varies geographically within species, driven by environmental gradients that alter growth and reproduction. However, environments can differ between adjacent habitats at single localities. In lowland Puerto Rico, both open (sunny, warm) and forested (shady, cool) habitats may be only meters apart. The lizard Anolis cristatellus lives in both habitats: it thermoregulates carefully in the open but is a thermoconformer in the forest. To determine whether reproduction differs between habitats, we compared reproductive cycles of females in open versus forest habitats at two localities for over 2 years. Open females were more likely than forest females to be reproductive throughout the year, probably because open females were able to bask and thereby achieve warmer body temperatures. These between-habitat differences in reproduction were especially marked in cool months and are equivalent in magnitude to those between populations separated by elevation. Thus, environmental differences (even on a microlandscape scale) matter to reproduction and probably to demography.

Novel genetic factors involved in resistance to Bacillus thuringiensis in Plutella xylostella.

The widespread and sustainable exploitation of the entomopathogen Bacillus thuringiensis (Bt) in pest control is threatened by the evolution of resistance. Although resistance is often associated with loss of binding of the Bt toxins to the insect midgut cells, other factors have been implicated. Here we used suppressive subtractive hybridization and gene expression suppression to identify additional molecular components involved in Bt-resistance in Plutella xylostella. We isolated transcripts from genes that were differentially expressed in the midgut of larvae from a resistant population, following ingestion of a Bt kurstaki HD1 strain-based commercial formulation (DiPel), and compared with a genetically similar susceptible population. Quantitative real-time polymerase-chain reaction (RT-PCR) analysis confirmed the differential basal expression of a subset of these genes. Gene expression suppression of three of these genes (P. xylostella cyclin-dependent kinase 5 regulatory subunit associated protein 1-like 1, stromal cell-derived factor 2-like 1 and hatching enzyme-like 1) significantly increased the pathogenicity of HD1 to the resistant population. In an attempt to link the multitude of factors reportedly influencing resistance to Bt with the well-characterized loss of toxin binding, we also considered Bt-resistance models in P. xylostella and other insects.

Why tropical forest lizards are vulnerable to climate warming.

Biological impacts of climate warming are predicted to increase with latitude, paralleling increases in warming. However, the magnitude of impacts depends not only on the degree of warming but also on the number of species at risk, their physiological sensitivity to warming and their options for behavioural and physiological compensation. Lizards are useful for evaluating risks of warming because their thermal biology is well studied. We conducted macrophysiological analyses of diurnal lizards from diverse latitudes plus focal species analyses of Puerto Rican Anolis and Sphaerodactyus. Although tropical lowland lizards live in environments that are warm all year, macrophysiological analyses indicate that some tropical lineages (thermoconformers that live in forests) are active at low body temperature and are intolerant of warm temperatures. Focal species analyses show that some tropical forest lizards were already experiencing stressful body temperatures in summer when studied several decades ago. Simulations suggest that warming will not only further depress their physiological performance in summer, but will also enable warm-adapted, open-habitat competitors and predators to invade forests. Forest lizards are key components of tropical ecosystems, but appear vulnerable to the cascading physiological and ecological effects of climate warming, even though rates of tropical warming may be relatively low.

Evolution of Chilean colonizing populations of Drosophila subobscura: lethal genes and chromosomal arrangements.

Knowledge of the frequency, distribution, and fate of lethal genes in chromosomal inversions helps to illuminate the evolution of recently founded populations. We analyze the relationship between lethal genes and inversions in two colonizing populations of D. subobscura in Chile. In the ancestral Palearctic populations of this species, lethal genes seem distributed at random on chromosomes. But in colonizing American populations, some lethal genes are associated with specific chromosomal arrangements. Some of these associated lethals were detected only during the first stages of the colonization (O( 3+4+2 )), and never thereafter, whereas others have persisted (O( 3+4+7 ) and O(5)). However, most lethal genes in American populations have been observed only once: they have arisen by novel mutation and soon disappear. Finally, recombination between different inversions has been observed in America. However, the persistence of lethal genes associated with the heterotic inversions O( 3+4+7 ) and O(5) could indicate that recombination inside these inversions is rare.

Global genetic change tracks global climate warming in Drosophila subobscura.

Comparisons of recent with historical samples of chromosome inversion frequencies provide opportunities to determine whether genetic change is tracking climate change in natural populations. We determined the magnitude and direction of shifts over time (24 years between samples on average) in chromosome inversion frequencies and in ambient temperature for populations of the fly Drosophila subobscura on three continents. In 22 of 26 populations, climates warmed over the intervals, and genotypes characteristic of low latitudes (warm climates) increased in frequency in 21 of those 22 populations. Thus, genetic change in this fly is tracking climate warming and is doing so globally.

TGF beta-mediated RhoA expression is necessary for epithelial-mesenchymal transition in the embryonic chick heart.

Endothelia in the atrioventricular canal (AVC) of the embryonic heart undergo an epithelial-mesenchymal transition (EMT) and migrate into the underlying extracellular matrix. We explore here whether RhoA mediates this EMT. RhoA was detected in all cells of the chick heart during the stages studied. Expression was elevated when EMT was actively occurring. Explants treated with C3 exoenzyme in collagen gel cultures showed a significant decrease in mesenchymal cell numbers. siRNA was used to inhibit RhoA mRNA, and both activated endothelial and mesenchymal cells decreased significantly with treatment. Loss of RhoA produced a reduction of RhoB, cyclin-b2, and beta-catenin messages showing that these genes are regulated downstream of RhoA. In contrast, runx-2 was not reduced. Inhibition of TGFbeta3 or TGFbeta2 activity caused a large reduction of RhoA message. These data place RhoA in TGFbeta regulated pathways for both endothelial activation and mesenchymal invasion and demonstrate a functional requirement during EMT.

Eicosanoid-mediated proinflammatory activity of Pseudomonas aeruginosa ExoU.

As Pseudomonas aeruginosa ExoU possesses two functional blocks of homology to calcium-independent (iPLA(2)) and cytosolic phospholipase A(2) (cPLA(2)), we addressed the question whether it would exhibit a proinflammatory activity by enhancing the synthesis of eicosanoids by host organisms. Endothelial cells from the HMEC-1 line infected with the ExoU-producing PA103 strain exhibited a potent release of arachidonic acid (AA) that could be significantly inhibited by methyl arachidonyl fluorophosphonate (MAFP), a specific PLA(2) inhibitor, as well as significant amounts of the cyclooxygenase (COX)-derived prostaglandins PGE(2) and PGI(2). Cells infected with an isogenic mutant defective in ExoU synthesis did not differ from non-infected cells in the AA release and produced prostanoids in significantly lower concentrations. Infection by PA103 induced a marked inflammatory response in two different in vivo experimental models. Inoculation of the parental bacteria into mice footpads led to an early increase in the infected limb volume that could be significantly reduced by inhibitors of both COX and lipoxygenase (ibuprofen and NDGA respectively). In an experimental respiratory infection model, bronchoalveolar lavage (BAL) from mice instilled with 10(4) cfu of PA103 exhibited a marked influx of inflammatory cells and PGE(2) release that could be significantly reduced by indomethacin, a non-selective COX inhibitor. Our results suggest that ExoU may contribute to P. aeruginosa pathogenesis by inducing an eicosanoid-mediated inflammatory response of host organisms.

A time series of evolution in action: a latitudinal cline in wing size in South American Drosophila subobscura.

Drosophila subobscura is geographically widespread in the Old World. Around the late 1970s, it was accidentally introduced into both South and North America, where it spread rapidly over broad latitudinal ranges. This invading species offers opportunities to study the speed and predictability of trait evolution on a geographic scale. One trait of special interest is body size, which shows a strong and positive latitudinal cline in many Drosophila species, including Old World D. subobscura. Surveys made about a decade after the invasion found no evidence of a size cline in either North or South America. However, a survey made in North America about two decades after the invasion showed that a conspicuous size cline had evolved and (for females) was coincident with that for Old World flies. We have now conducted parallel studies on 10 populations (13 degrees of latitude) of flies, collected in Chile in spring 1999. After rearing flies in the laboratory for several generations, we measured wing sizes and compared geographic patterns (versus latitude or temperature) for flies on all three continents. South American females have now evolved a significant latitudinal size cline that is similar in slope to that of Old World and of North American flies. Rates of evolution (haldanes) for females are among the highest ever measured for quantitative traits. In contrast, the size cline is positive but not significant for South or North American males. At any given latitude, South American flies of both sexes are relatively large; this in part reflects the relatively cool climate of coastal Chile. Interestingly, the sections of the wing that generate the size cline for females differ among all three continents. Thus, although the evolution of overall wing size is predictable on a geographic scale (at least for females), the evolution of size of particular wing components is decidedly not.

Behavioral drive versus behavioral inertia in evolution: a null model approach.

Some biologists embrace the classical view that changes in behavior inevitably initiate or drive evolutionary changes in other traits, yet others note that behavior sometimes inhibits evolutionary changes. Here we develop a null model that quantifies the impact of regulatory behaviors (specifically, thermoregulatory behaviors) on body temperature and on performance of ectotherms. We apply the model to data on a lizard (Anolis cristatellus) and show that thermoregulatory behaviors likely inhibit selection for evolutionary shifts in thermal physiology with altitude. Because behavioral adjustments are commonly used by ectotherms to regulate physiological performance, regulatory behaviors should generally constrain rather than drive evolution, a phenomenon we call the "Bogert effect." We briefly review a few other examples that contradict the classical view of behavior as the inevitable driving force in evolution. Overall, our analysis and brief review challenge the classical view that behavior is invariably the driving force in evolution, and instead our work supports the alternative view that behavior has diverse--and sometimes conflicting--effects on the directions and rates at which other traits evolve.

Personality measurement in applied psychology as illustrated by the 16 personality factor test

No campo teórico, poder-se-ia esperar que um teste baseado numa determinação prévia das estruturas da personalidade inerentes no organismo tivesse maior validade de critério e demonstrasse ser mais receptivo à orientação das leis psicológicas gerais do que um conjunto de escalas subjetivas e a priori. Tem sido demonstrado que resultados consistentes quanto à escritura tem sido obtidos por análises fatoriais da personalidade, nos últimos vinte anos. No domínio das respostas-questionário, esta pesquisa básica foi feita com o Questionário dos 16 Fatores de Personalidade, o 16 P.F. Este teste, traduzido para muitas línguas, tem demonstrado, após cinco a dez anos de uso, altas validades, como critério de predição, tendo em vista finalidades industriais , educacionais e clínicas. Tais aplicações práticas do teste em vários campos baseiam-se no fato evidente, porém sobrestimado, de que é o próprio interessado que se apresenta para avaliação psicológica ou orientação, seja no trabalho, na escola ou na clínica. Já existem atualmente em disponibilidade normas para muitos grupos e há pesos para os fatores determinados através de pesquisas, capazes de possibilitar as melhores estimativas de sucesso em várias ocupações. Uma das vantagens não menos importante deste teste é o fato de relacionar com as dimensões naturais que podem ser medidas também noutros níveis de idade, para os estudos de desenvolvimento. Por exemplo, o Harvard Florence Study utilizou o High School Personality Questionnaire (HSPQ (15)) em sujeitos por volta de doze anos de idade e que poderiam ser futuramente testados pelo 16 P.F. A Forma A do Teste 16 P.F. foi traduzida para o português por Eugênia Moraes de Andrade e Dulce Godoy Alves, do Instituto de Administração, S. Paulo, enquanto que o Dr. Enzo Azzi e Nelson de Campos Pires, também de S. Paulo, tem desempenhado importantes papéis na tradução de semelhantes testes fatoriais para serem usados no Brasil.(AU)

O valor da teoria fatorial para a moderna elaboração de testes de personalidade

O autor demonstra o valor da teoria e da técnica fatorial para o estudo da estrutura da personalidade humana e a construção de testes de personalidade. (AU)

La salud pública como problema internacional

El texto original en ingles aparece en el American Journal of Public Health, p. 1133-38, nov. 1944