Genetic Susceptibility Modifies Relationships Between Air Pollutants and Stroke Risk: A Large Cohort Study

BACKGROUND

The extent to which genetic susceptibility modifies the associations between air pollutants and the risk of incident stroke is still unclear. This study was designed to investigate the separate and joint associations of long-term exposure to air pollutants and genetic susceptibility on stroke risk.

METHODS

The participants of this study were recruited by the UK Biobank between 2006 and 2010. These participants were followed up from the enrollment until the occurrence of stroke events or censoring of data. Hazard ratios (HRs) and 95% CIs for stroke events associated with long-term exposure to air pollutants were estimated by fitting both crude and adjusted Cox proportional hazards models. Additionally, the polygenic risk score was calculated to estimate whether the polygenic risk score modifies the associations between exposure to air pollutants and incident stroke.

RESULTS

A total of 502 480 subjects were included in this study. After exclusion, 452 196 participants were taken into the final analysis. During a median follow-up time of 11.7 years, 11 334 stroke events were observed, with a mean age of 61.60 years, and men accounted for 56.2% of the total cases. Long-term exposures to particulate matter with an aerodynamic diameter smaller than 2.5 µm (adjusted HR, 1.70 [95% CI, 1.43-2.03]) or particulate matter with an aerodynamic diameter smaller than 10 µm (adjusted HR, 1.50 [95% CI, 1.36-1.66]), nitrogen dioxide (adjusted HR, 1.10 [95% CI, 1.07-1.12]), and nitrogen oxide (adjusted HR, 1.04 [95% CI, 1.02-1.05]) were pronouncedly associated with increased risk of stroke. Meanwhile, participants with high genetic risk and exposure to high air pollutants had ≈45% (31%, 61%; particulate matter with an aerodynamic diameter smaller than 2.5 µm), 48% (33%, 65%; particulate matter with an aerodynamic diameter smaller than 10 µm), 51% (35%, 69%; nitrogen dioxide), and 39% (25%, 55%; nitrogen oxide) higher risk of stroke compared with those with low genetic risk and exposure to low air pollutants, respectively. Of note, we observed additive and multiplicative interactions between genetic susceptibility and air pollutants on stroke events.

CONCLUSIONS

Chronic exposure to air pollutants was associated with an increased risk of stroke, especially in populations at high genetic risk.

Social support networks and life cycle stage of Venezuelan immigrant families

OBJECTIVE

To understand the structures of social networks of interiorized Venezuelan immigrant families and the life cycle stage they are in.

METHODS

Qualitative multiple-case study with families from the Interiorization Program residing in the Greater Florianópolis, Brazil. Screening occurred through social networks and key informants. For data collection, the photovoice technique and semi-structured interviews were used, categorized with the help of the Atlas.ti software. Genograms and ecomaps were elaborated.

RESULTS

Of the 4 families interviewed, totaling 7 members with young children, the nuclear family was identified as the main informal support network. Formal networks included schools, churches, and civil society.

CONCLUSION

Families rely heavily on their nuclear structure for support, with formal institutions acting as secondary resources. The predominant life cycle stage is focused on families with young children. More efforts are needed to strengthen formal support networks.

Life cycle phases: Literature review and new classification proposal for application in healthcare

INTRODUCTION

Although uncommon in dentistry, the concept of the life cycle holds great importance for dental professionals in identifying crucial intervention opportunities and determining the optimal timing for treatments and procedures.

OBJECTIVE

To carry out a review of the literature on life cycle classifications and their distinct phases, evaluating their applicability in healthcare.

METHODS

A literature review was performed, searching for articles in PubMed, SciELO, National Health Library (BvB), and Google Scholar databases, as well as relevant books. The keywords "life cycle," "life stages," "human development," "age groups," and "biological age" were used. Relevant articles were selected by analyzing their titles and abstracts, and read in full to confirm their inclusion in the research.

RESULTS

Nine distinct life cycle classifications were found, each with unique criteria.

CONCLUSION

Based on the comprehensive literature review, a novel classification was proposed (The 10-phase Life Cycle), which encompasses dental, growth, physiological aging, sociocultural, and behavioral characteristics, aiming to enhance communication among healthcare professionals, particularly those engaged in the growth, development, and aging processes of human beings.

Living arrangements and socioeconomic-based health disparities in Mexico

OBJECTIVE

To investigate the role living arrangements play in the co-dynamics of socioeconomic position and health in the latter part of life.

MATERIALS AND METHODS

Based on longitudinal data from the Mexican Health and Aging Study (MHAS), latent class analysis (LCA) and locally weighted regressions, in this article we estimate age trajectories to examine the degree to which wealth and health-related outcomes correlate with typical living arrangement dynamics.

RESULTS

Main results suggest a complex dynamic relationship between living arrangements and social inequalities in health, with important differences by sex, unlike mortality trends as they appear to diverge with differences in wealth regardless of household structure.

CONCLUSIONS

Our methodological approach provides new insights regarding the likely effect household structure plays when analyzing the dynamics of social inequality. To date, this is the first longitudinal analysis to offer this kind of empirical evidence for the region.

Clinical and Radiological Differences in Patients Following Traumatic SCI at Different Ages

BACKGROUND

Traumatic spinal cord injury (SCI) is a lesion that can affect several spinal structures, including the vertebrae, spinal cord, ligaments, and other adjacent parts of the spine. Traumatic spinal cord injury (SCI) can cause functional changes in patients of different ages.

MATERIAL AND METHODS

The study aims to determine whether there are social, clinical, and radiological differences between young, middle-aged, and elderly adults with SCI caused by a ground-level fall. This retrospective study analyzed the records of patients with a clinical diagnosis of SCI. It enrolled patients with traumatic spinal cord injury after a ground-level fall divided as follows: young aged adults 18-35 years of age (G1); middle-aged adults aged 36-60 years (G2); and elderly adults aged over 60 years (G3). Their clinical, social, and radiological variables were analyzed.

RESULTS

It is observed that low schooling level, being widowed, and being a homemaker were more frequently encountered among elderly adults, whereas being single was more common in middle-aged adults. The morphologic diagnosis of compression fracture and the associated injury of facial trauma occurred more frequently in elderly adults, with an increasing tendency with age. Conservative therapeutic management was most commonly encountered in elderly adults, compared to surgery from a posterior approach in middle-aged adults. Listhesis was better identified in middle-aged adults by computed tomography (CT). Spinal cord contusion and injury to the C1 vertebra were demonstrated in young adults by magnetic resonance imaging (MRI).

CONCLUSIONS

1. Elderly adults with low education level, widowed, and homemakers were more susceptible to SCI caused by a fall. 2. Single marital status was more frequently noted in young adults. 3. The most frequent clinical aspects were the morphological aspect of compression fracture and fa-cial trauma as an associated injury in elderly adults, with the occurrence of facial trauma increasing with age. 4. Conservative therapeutic management was more common in elderly adults than surgery from a po-sterior approach in middle-aged adults. 5. Re-garding the radiological aspects of CT, listhesis was better identified in middle-aged adults. Spi-nal cord contusions and C1 vertebra lesions were better identified in young adults by MRI.

Microscopic and molecular evaluation of Strongyloides venezuelensis in an experimental life cycle using Wistar rats

INTRODUCTION

Strongyloides venezuelensis is a nematode whose natural host is rats. It is used as a model for the investigation of human strongyloidiasis caused by S. stercoralis. The latter is a neglected tropical disease in Ecuador where there are no specific plans to mitigate this parasitic illness.

OBJECTIVE

To evaluate the stages of S. venezuelensis in an experimental life cycle using Wistar rats.

MATERIALS AND METHODS

Male Wistar rats were used to replicate the natural biological cycle of S. venezuelensis and describe its morphometric characteristics, as well as its parasitic development. Furthermore, the production of eggs per gram of feces was quantified using two diagnostic techniques and assessment of parasite load: Kato-Katz and qPCR.

RESULTS

Viable larval stages (L1, L2, L3) could be obtained up to 96 hours through fecal culture. Parthenogenetic females were established in the duodenum on the fifth day postinfection. Fertile eggs were observed in the intestinal tissue and fresh feces where the production peak occurred on the 8th. day post-infection. Unlike Kato-Katz, qPCR detected parasitic DNA on days not typically reported.

CONCLUSIONS

The larval migration of S. venezuelensis within the murine host in an experimental environment was equivalent to that described in its natural biological cycle. The Kato-Katz quantitative technique showed to be quick and low-cost, but the qPCR had greater diagnostic precision. This experimental life cycle can be used as a tool for the study of strongyloidiasis or other similar nematodiasis.

Saccharomyces spores are born prepolarized to outgrow away from spore-spore connections and penetrate the ascus wall

How nonspore haploid Saccharomyces cells choose sites of budding and polarize towards pheromone signals in order to mate has been a subject of intense study. Unlike nonspore haploids, sibling spores produced via meiosis and sporulation by a diploid cell are physically interconnected and encased in a sac derived from the old cell wall of the diploid, called the ascus. Nonspore haploids bud adjacent to previous sites of budding, relying on stable cortical landmarks laid down during prior divisions, but because spore membranes are made de novo, it was assumed that, as is known for fission yeast, Saccharomyces spores break symmetry and polarize at random locations. Here, we show that this assumption is incorrect: Saccharomyces cerevisiae spores are born prepolarized to outgrow, prior to budding or mating, away from interspore bridges. Consequently, when spores bud within an intact ascus, their buds locally penetrate the ascus wall, and when they mate, the resulting zygotes adopt a unique morphology reflective of repolarization towards pheromone. Long-lived cortical foci containing the septin Cdc10 mark polarity sites, but the canonical bud site selection programme is dispensable for spore polarity, thus the origin and molecular composition of these landmarks remain unknown. These findings demand further investigation of previously overlooked mechanisms of polarity establishment and local cell wall digestion and highlight how a key step in the Saccharomyces life cycle has been historically neglected.

Socioeconomic Life Course Models and Oral Health: A Longitudinal Analysis

We compared socioeconomic life course models to decompose the direct and mediated effects of socioeconomic status (SES) in different periods of life on late-life oral health. We used data from 2 longitudinal Swedish studies: the Level of Living Survey and the Swedish Panel Study of Living Conditions of the Oldest Old. Two birth cohorts (older, 1925 to 1934; younger, 1944 to 1953) were followed between 1968 and 2011 with 6 waves. SES was measured with 4 indicators of SES and modeled as a latent variable. Self-reported oral health was based on a tooth conditions question. Variables in the younger and older cohorts were grouped into 4 periods: childhood, young/mid-adulthood, mid /late adulthood, late adulthood/life. We used structural equation modeling to fit the following into lagged-effects life course models: 1) chain of risk, 2) sensitive period with late-life effect, 3) sensitive period with early- and late-life effects, 4) accumulation of risks with cross-sectional effects, and 5) accumulation of risks. Chain of risk was incorporated into all models and combined with accumulation, with cross-sectional effects yielding the best fit (older cohort: comparative fit index = 0.98, Tucker-Lewis index = 0.98, root mean square error of approximation = 0.04, weighted root mean square residual = 1.51). For the older cohort, the chain of SES from childhood → mid-adulthood → late adulthood → late life showed the following respective standardized coefficients: 053, 0.92, and 0.97. The total effect of childhood SES on late-life tooth loss (standardized coefficient: -0.23 for older cohort, -0.17 for younger cohort) was mediated by previous tooth loss and SES. Cross-sectional effects of SES on tooth loss were observed throughout the life course, but the strongest coefficients were at young/mid-adulthood (standardized coefficient: -0.41 for older cohort, -0.45 for younger cohort). SES affects oral health cumulatively over the life course and through a chain of risks. Actions to improve socioeconomic conditions in early life might have long-lasting effects on health if they help prevent people from becoming trapped in a chain of risks.

A link between mitochondrial gene expression and life stage morphologies in Trypanosoma cruzi

The protozoan Trypanosoma cruzi has a complicated dual-host life cycle, and starvation can trigger transition from the replicating insect stage to the mammalian-infectious nonreplicating insect stage (epimastigote to trypomastigote differentiation). Abundance of some mature RNAs derived from its mitochondrial genome increase during culture starvation of T. cruzi for unknown reasons. Here, we examine T. cruzi mitochondrial gene expression in the mammalian intracellular replicating life stage (amastigote), and uncover implications of starvation-induced changes in gene expression. Mitochondrial RNA levels in general were found to be lowest in actively replicating amastigotes. We discovered that mitochondrial respiration decreases during starvation in insect stage cells, despite the previously observed increases in mitochondrial mRNAs encoding electron transport chain (ETC) components. Surprisingly, T. cruzi epimastigotes in replete medium grow at normal rates when we genetically compromised their ability to perform insertion/deletion editing and thereby generate mature forms of some mitochondrial mRNAs. However, these cells, when starved, were impeded in the epimastigote to trypomastigote transition. Further, they experience a short-flagella phenotype that may also be linked to differentiation. We hypothesize a scenario where levels of mature RNA species or editing in the single T. cruzi mitochondrion are linked to differentiation by a yet-unknown signaling mechanism.

Life cycle stages, specific organelles and invasion mechanisms of Eimeria species

Apicomplexans, including species of Eimeria, pose a real threat to the health and wellbeing of animals and humans. Eimeria parasites do not infect humans but cause an important economic impact on livestock, in particular on the poultry industry. Despite its high prevalence and financial costs, little is known about the cell biology of these 'cosmopolitan' parasites found all over the world. In this review, we discuss different aspects of the life cycle and stages of Eimeria species, focusing on cellular structures and organelles typical of the coccidian family as well as genus-specific features, complementing some 'unknowns' with what is described in the closely related coccidian Toxoplasma gondii.

Possible Role of Fish as Transport Hosts for Dracunculus spp. Larvae

To inform Dracunculus medinensis (Guinea worm) eradication efforts, we evaluated the role of fish as transport hosts for Dracunculus worms. Ferrets fed fish that had ingested infected copepods became infected, highlighting the importance of recommendations to cook fish, bury entrails, and prevent dogs from consuming raw fish and entrails.

[Biological parameters of Meccus phyllosomus phyllosomus (Burmeister), 1835, Triatoma recurva (Stål), 1868 (Hemiptera, Reduviidae) and their laboratory hybrids]

INTRODUCTION

Hybrids from species and subspecies of Mexican triatomines have shown outstanding biological and behavioral characteristics as compared with their parental groups. This could lead to an increasing risk of transmission of Trypanosoma cruzi to human and animal reservoir hosts.

OBJECTIVE

To describe and compare biological parameters related to the life cycle of Triatoma recurva, Meccus phyllosomus phyllosomus and their laboratory hybrids and estimate their risk as transmitters of T. cruzi to humans.

MATERIALS AND METHODS

We kept a cohort of each one of the three groups (T. recurva, M. p. phyllosomus and their hybrids) under similar laboratory conditions and then compared them to record the data related to their life cycles, number of blood meals to molt, mortality rates, egg eclosion rates and female fecundity.

RESULTS

The hybrid cohort showed the lowest mean time from first-instar nymph to adult (136.6 ± 17.5 days). The number of blood meals from molt to next instar (13.4 ± 1.7; 15.6 ± 5.2) was higher in the hybrid and T. recurva cohorts. The hybrid cohort showed the lowest mortality rate (29.5%) and the highest rate (70%) of adult females at the end of the biological cycle. Fecundity per day per female (range: 1.1 ± 0.6- 1.6 ± 0.7 eggs) was similar in the three cohorts. Egg hatching rate was higher than 70% in both hybrid and M. p. phyllosomus cohorts.

CONCLUSION

The hybrid cohort showed some outstanding biological characteristics, which would entail a higher risk of transmission of T. cruzi to hosts than their parentals.

Gut Microbiome: What We Do and Don't Know

Within the last decade, research regarding the human gut microbiome has exploded. While the gastrointestinal tract was once regarded simply as a digestive organ, new technologies have led the science world to wonder about the impact that the gut microbiota may have on human health and disease. The gut microbiome is now becoming known for its role in metabolism, immune defense, and behavior. From in utero variations to those that rapidly occur post partum, our gut microbiome changes with age, environment, stress, diet, and health status as well as medication exposure. This article reviews what is currently known regarding various influences on the gut microbiome and is meant to encourage the reader to further explore the unknown.

Roles of maternal effects and nuclear genetic composition change across the life cycle of crop-wild hybrids

• Premise of the study: The fitness of an offspring may depend on its nuclear genetic composition (via both parental genotypes) as well as on genetic maternal effects (via only the maternal parent). Understanding the relative importance of these two genetic factors is particularly important for research on crop-wild hybridization, since traits with important genetic maternal effects (e.g., seed size) often differ among crops and their relatives. We hypothesized that the effects of these genetic factors on fitness components would change across the life cycle of hybrids.• Methods: We followed seed, plant size, and reproductive traits in field experiments with wild and four crop-wild hybrids of sunflower (Helianthus annuus), which differed in nuclear genetic composition and maternal parent (wild or F1 hybrid).• Key results: We identified strong genetic maternal effects for early life cycle characteristics, with seeds produced on an F1 mother having premature germination, negligible seed dormancy, and greater seedling size. Increased percentages of crop alleles also increased premature germination and reduced dormancy in seeds produced on a wild mother. For mature plants, nuclear genetic composition dominated: greater percentages of crop alleles reduced height, branching, and fecundity.• Conclusions: Particular backcrosses between hybrids and wilds may differentially facilitate movement of crop alleles into wild populations due to their specific features. For example, backcross seeds produced on wild mothers can persist in the seed bank, illustrating the importance of genetic maternal effects, whereas backcross individuals with either wild or F1 mothers have high fecundity, resulting from their wild-like nuclear genetic composition.

The granuloma in tuberculosis: dynamics of a host-pathogen collusion

A granuloma is defined as an inflammatory mononuclear cell infiltrate that, while capable of limiting growth of Mycobacterium tuberculosis, also provides a survival niche from which the bacteria may disseminate. The tuberculosis lesion is highly dynamic and shaped by both, immune response elements and the pathogen. In the granuloma, M. tuberculosis switches to a non-replicating but energy-generating life style whose detailed molecular characterization can identify novel targets for chemotherapy. To secure transmission to a new host, M. tuberculosis has evolved to drive T cell immunity to the point that necrotizing granulomas leak into bronchial cavities to facilitate expectoration of bacilli. From an evolutionary perspective it is therefore questionable whether vaccination and immunity enhancing strategies that merely mimic the natural immune response directed against M. tuberculosis infection can overcome pulmonary tuberculosis in the adult population. Juxtaposition of molecular pathology and immunology with microbial physiology and the use of novel imaging approaches afford an integrative view of the granuloma’s contribution to the life cycle of M. tuberculosis. This review revisits the different input of innate and adaptive immunity in granuloma biogenesis, with a focus on the co-evolutionary forces that redirect immune responses also to the benefit of the pathogen, i.e., its survival, propagation, and transmission.

Tegumental ultrastructures of Echinoparyphium recurvatum according to developmental stages

The present study was performed to observe tegumental ultrastructure of Echinoparyphium recurvatum according to developmental stages. Worms (1, 3, 5 and 15-day old) were recovered from chicks experimentally infected with metacercariae from Radix auricularia coreana. One-day old worms were elongated and ventrally concave, and covered with peg-like tegumental spines except the adjacent areas of the head crown and excretory pore. Type I sensory papillae were distributed on the lip of the oral sucker, and grouped ciliated papillae were around the oral sucker. Peg-like tegumental spines were densely distributed on the anterior surface of the ventral sucker level. The ventral sucker had an aspinous tegument and no sensory papillae. Tegumental spines on the posterior surface of the ventral sucker level were sparsely distributed and disappeared posteriorly. In 3 and 5-day old worms, the tegument around the oral sucker was aspinose and wrinkled concentrically. The ventral sucker had a wrinkled tegument and many bulbous papillae. Type I sensory papillae were distributed between the bulbous papillae. Tegumental spines were spade-shaped with a terminal tip. A total of 45 collar spines including 4 end group ones on both ventral corners was alternately arranged in 2 rows. The 15-day old worms were very stout and their tegumental spines were tongue-shaped without a terminal tip. From the above results, it is confirmed that the surface ultrastructure of E. recurvatum was generally similar to that of other echinostomatid flukes. However, some features, i.e., morphological change of tegumental spines and appearance of sensory papillae on the ventral sucker according to development, and number, shape and arrangement of collar spines, were characteristic, which may be of taxonomic and bioecological significance.