Urban Folk Medicine: A Functional Overview

Social and economic functions of folk illness and folk medicine are fairly well known for rural contexts but still lack codification for urban milieus. In this exploratory paper, folk health practices are examined in terms of their response to urban socioeconomic characteristics. Such practices appear to serve functions of acculturation, guilt displacement resulting from failure to achieve, and subgroup identity maintenance, among others. Folk practices are resilient, readily shifting to adjunct functions of healing under pressure from effective modern medical and welfare systems . [medical anthropology, urban anthropology, curanderismo, ethnology, health]     

Diagnosis and Treatment of Essential Fatty Acid Deficiency in Man

Essential fatty acid deficiency was found on four occasions in three adult patients with malabsorption after intestinal resection. Diagnosis was primarily based on the gas chromatographic finding of the abnormal fatty acid 5, 8, 11- (ω9) eicosatrienoic acid in plasma lecithin. None of the patients had received parenteral nutrition with a fat-free source of calories but all had been on a reduced intake of dietary fat at some stage. Treatment with intravenous Intralipid rapidly reversed the abnormal plasma fatty acid pattern and also cleared the rash in the patient wih he most severe deficiency.     

Photosynthetic characteristics of dipterocarp seedlings in three tropical rain forest light environments: a basis for niche partitioning?

In three tropical rain forest light environments in Sabah, Malaysia, we compared photosynthesis in seedlings of ten climax tree species with putatively differing shade tolerances. The objectives of the study were (a) to characterise the range of photosynthetic responses in ten species of the Dipterocarpaceae and (b) to elucidate those photosynthetic characteristics that might provide a basis for niche partitioning. Seedlings were acclimated (c. 7 months) in three light environments; understorey, partial shade and a gap (140 m²). The light environments represented a gradation in median diurnal (0630–1830 hours) photon flux density (PFD) ranging from understorey (4.7 μmol m⁻² s⁻¹), through partial shade (21.2 μmol m⁻² s⁻¹) to gap (113.7 μmol m⁻² s⁻¹). Integrated diurnal PFD were in the sequence gap > partial shade > understorey (15.2, 4.7, 1.3 mol m⁻² day⁻¹, respectively). In gap-acclimated plants, species differed in the photosynthetic light-response variables apparent quantum yield, dark respiration rate, light compensation point, net saturated leaf assimilation rate (A _sat), and in stomatal conductance (g _s sat) when assimilation rate (A) was saturated. A light-demanding pioneer species (Macaranga hypoleuca) and a shade-demanding understorey species (Begonia sp.) had, respectively, higher and lower A _sat and g _s sat than the dipterocarp species. In high-light conditions A _sat and g _s sat were strongly positively correlated in dipterocarp species. Differing photosynthetic characteristics of gap-acclimated plants suggest that, in these dipterocarp species, different rates of carbon fixation may be an important factor contributing towards niche partitioning. Mean integrated diurnal A (A _diurnal) in the gap, partial shade and understory were, respectively, 122.9, 52.7, 20.5 mmol m⁻² day⁻¹. Differences occurred in A _diurnal of dipterocarp species between light environments. When Macaranga was included, differences in A _diurnal were evident in the gap and partial shade, and in both cases were attributed to the pioneer. For the variable A _diurnal, there was of a shift in the rank position of Macaranga among light environments, but a shift did not occur among the dipterocarp species. Results from this study are consistent with the idea that rates of carbon fixation per unit leaf area may contribute towards niche differentiation between the climax and single pioneer species, but not within the group of climax species. Other physiological and/or carbon allocation factors may be involved in any niche partitioning; dipterocarp species often have inherently different growth rates and susceptibility to herbivory. As an alternative to niche partitioning, dipterocarp species may co-exist in natural light environments as a result of habitat disequilibrium or purely stochastic processes. Received: 2 April 1997 / Accepted: 13 July 1997     

Impacts of logging on density-dependent predation of dipterocarp seeds in a South East Asian rainforest

Much of the forest remaining in South East Asia has been selectively logged. The processes promoting species coexistence may be the key to the recovery and maintenance of diversity in these forests. One such process is the Janzen-Connell mechanism, where specialized natural enemies such as seed predators maintain diversity by inhibiting regeneration near conspecifics. In Neotropical forests, anthropogenic disturbance can disrupt the Janzen-Connell mechanism, but similar data are unavailable for South East Asia. We investigated the effects of conspecific density (two spatial scales) and distance from fruiting trees on seed and seedling survival of the canopy tree Parashorea malaanonan in unlogged and logged forests in Sabah, Malaysia. The production of mature seeds was higher in unlogged forest, perhaps because high adult densities facilitate pollination or satiate pre-dispersal predators. In both forest types, post-dispersal survival was reduced by small-scale (1 m(2)) conspecific density, but not by proximity to the nearest fruiting tree. Large-scale conspecific density (seeds per fruiting tree) reduced predation, probably by satiating predators. Higher seed production in unlogged forest, in combination with slightly higher survival, meant that recruitment was almost entirely limited to unlogged forest. Thus, while logging might not affect the Janzen-Connell mechanism at this site, it may influence the recruitment of particular species.     

Learning to understand others' actions

Despite nearly two decades of research on mirror neurons, there is still much debate about what they do. The most enduring hypothesis is that they enable 'action understanding'. However, recent critical reviews have failed to find compelling evidence in favour of this view. Instead, these authors argue that mirror neurons are produced by associative learning and therefore that they cannot contribute to action understanding. The present opinion piece suggests that this argument is flawed. We argue that mirror neurons may both develop through associative learning and contribute to inferences about the actions of others.     

Enhanced statistical tests for GWAS in admixed populations: assessment using African Americans from CARe and a Breast Cancer Consortium

While genome-wide association studies (GWAS) have primarily examined populations of European ancestry, more recent studies often involve additional populations, including admixed populations such as African Americans and Latinos. In admixed populations, linkage disequilibrium (LD) exists both at a fine scale in ancestral populations and at a coarse scale (admixture-LD) due to chromosomal segments of distinct ancestry. Disease association statistics in admixed populations have previously considered SNP association (LD mapping) or admixture association (mapping by admixture-LD), but not both. Here, we introduce a new statistical framework for combining SNP and admixture association in case-control studies, as well as methods for local ancestry-aware imputation. We illustrate the gain in statistical power achieved by these methods by analyzing data of 6,209 unrelated African Americans from the CARe project genotyped on the Affymetrix 6.0 chip, in conjunction with both simulated and real phenotypes, as well as by analyzing the FGFR2 locus using breast cancer GWAS data from 5,761 African-American women. We show that, at typed SNPs, our method yields an 8% increase in statistical power for finding disease risk loci compared to the power achieved by standard methods in case-control studies. At imputed SNPs, we observe an 11% increase in statistical power for mapping disease loci when our local ancestry-aware imputation framework and the new scoring statistic are jointly employed. Finally, we show that our method increases statistical power in regions harboring the causal SNP in the case when the causal SNP is untyped and cannot be imputed. Our methods and our publicly available software are broadly applicable to GWAS in admixed populations.     

Evolution of RXLR-Class Effectors in the Oomycete Plant Pathogen Phytophthora ramorum

Phytophthora plant pathogens contain many hundreds of effectors potentially involved in infection of host plants. Comparative genomic analyses have shown that these effectors evolve rapidly and have been subject to recent expansions. We examined the recent sequence evolution of RXLR-class effector gene families in the sudden oak death pathogen, P. ramorum. We found that P. ramorum RXLR effectors have taken multiple evolutionary paths, including loss or gain of repeated domains, recombination or gene conversion among paralogs, and selection on point mutations. Sequencing of homologs from two subfamilies in P. ramorum’s closest known relatives revealed repeated gene duplication and divergence since speciation with P. lateralis. One family showed strong signatures of recombination while the other family has evolved primarily by point mutation. Comparison of a small number of the hundreds of RXLR-class effectors across three clonal lineages of P. ramorum shows striking divergence in alleles among lineages, suggesting the potential for functional differences between lineages. Our results suggest future avenues for examination of rapidly evolving effectors in P. ramorum, including investigation of the functional and coevolutionary significance of the patterns of sequence evolution that we observed.     

Combining a CD20 Chimeric Antigen Receptor and an Inducible Caspase 9 Suicide Switch to Improve the Efficacy and Safety of T Cell Adoptive Immunotherapy for Lymphoma

Modification of T cells with chimeric antigen receptors (CAR) has emerged as a promising treatment modality for human malignancies. Integration of co-stimulatory domains into CARs can augment the activation and function of genetically targeted T cells against tumors. However, the potential for insertional mutagenesis and toxicities due to the infused cells have made development of safe methods for removing transferred cells an important consideration. We have genetically modified human T cells with a lentiviral vector to express a CD20-CAR containing both CD28 and CD137 co-stimulatory domains, a “suicide gene” relying on inducible activation of caspase 9 (iC9), and a truncated CD19 selectable marker. Rapid expansion (2000 fold) of the transduced T cells was achieved in 28 days after stimulation with artificial antigen presenting cells. Transduced T cells exhibited effective CD20-specific cytotoxic activity in vitro and in a mouse xenograft tumor model. Activation of the iC9 suicide switch resulted in efficient removal of transduced T cells both in vitro and in vivo. Our work demonstrates the feasibility and promise of this approach for treating CD20⁺ malignancies in a safe and more efficient manner. A phase I clinical trial using this approach in patients with relapsed indolent B-NHL is planned.     

Gene flow in environmental Legionella pneumophila leads to genetic and pathogenic heterogeneity within a Legionnaires’ disease outbreak

Background

Legionnaires’ disease is a severe form of pneumonia caused by the environmental bacterium Legionella pneumophila. Outbreaks commonly affect people with known risk factors, but the genetic and pathogenic complexity of L. pneumophila within an outbreak is not well understood. Here, we investigate the etiology of the major Legionnaires’ disease outbreak that occurred in Edinburgh, UK, in 2012, by examining the evolutionary history, genome content, and virulence of L. pneumophila clinical isolates.

Results

Our high resolution genomic approach reveals that the outbreak was caused by multiple genetic subtypes of L. pneumophila, the majority of which had diversified from a single progenitor through mutation, recombination, and horizontal gene transfer within an environmental reservoir prior to release. In addition, we discover that some patients were infected with multiple L. pneumophila subtypes, a finding which can affect the certainty of source attribution. Importantly, variation in the complement of type IV secretion systems encoded by different genetic subtypes correlates with virulence in a Galleria mellonella model of infection, revealing variation in pathogenic potential among the outbreak source population of L. pneumophila.

Conclusions

Taken together, our study indicates previously cryptic levels of pathogen heterogeneity within a Legionnaires’ disease outbreak, a discovery that impacts on source attribution for future outbreak investigations. Furthermore, our data suggest that in addition to host immune status, pathogen diversity may be an important influence on the clinical outcome of individual outbreak infections.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-014-0504-1) contains supplementary material, which is available to authorized users.