Senescence in natural populations of animals: Widespread evidence and its implications for bio-gerontology

That senescence is rarely, if ever, observed in natural populations is an oft-quoted fallacy within bio-gerontology. We identify the roots of this fallacy in the otherwise seminal works of Medawar and Comfort, and explain that under antagonistic pleiotropy or disposable soma explanations for the evolution of senescence there is no reason why senescence cannot evolve to be manifest within the life expectancies of wild organisms. The recent emergence of long-term field studies presents irrefutable evidence that senescence is commonly detected in nature. We found such evidence in 175 different animal species from 340 separate studies. Although the bulk of this evidence comes from birds and mammals, we also found evidence for senescence in other vertebrates and insects. We describe how high-quality longitudinal field data allow us to test evolutionary explanations for differences in senescence between the sexes and among traits and individuals. Recent studies indicate that genes, prior environment and investment in growth and reproduction influence aging rates in the wild. We argue that – with the fallacy that wild animals do not senesce finally dead and buried – collaborations between bio-gerontologists and field biologists can begin to test the ecological generality of purportedly ‘public’ mechanisms regulating aging in laboratory models.     

The implications of obesity on pregnancy

Maternal obesity is defined as a body mass index of 30 or above. It is a common clinical problem and its incidence is increasing. It is associated with an increase in both maternal and perinatal mortality and morbidity. Super-obesity in particular poses unique challenges during the antenatal, intrapartum and postnatal periods and may require the involvement of specialists from a number of fields. Women who are obese are a high-risk group and must be carefully risk assessed in order to optimize their care.     

(A)e(s)th(et)ics of Brain Imaging. Visibilities and Sayabilities in Functional Magnetic Resonance Imaging

Producing and interpreting functional brain data is part of the negotiation we imagine our brain. To take a closer look at the idea of brain imaging as a form of visual knowledge, it is necessary to put the research of today into a historical context. In my article I will point to a specific approach of functional imaging which depends on historical shifts entangled with the visual aspect of producing pictures of the brain. I will bring out the interaction of issues like techniques, models and historical assumptions of the brain and link them with the way the brain images are presented. The aesthetic dimensions (Rancière) in the pictures are also questions of ethics and normativity.     

Eroded Valves,Recurrent Pleural Effusions,and Ultimately Heart–Liver Transplant

A patient with eroded tricuspid and pulmonic valves, who eventually developed elevated right atrial and systemic venous pressure that led to hepatic cirrhosis and recurrent pleural effusion, is presented. The complex issues involved over a long period in this patient, who ultimately required combined heart and liver transplant, are discussed.     

Evaluation of toxicity after acute accidental methotrexate ingestions in children under 6 years old: a 16-year multi-center review

Context: There is little data on the frequency of adverse events following acute methotrexate ingestions in pediatric patients. Likewise, recommendations for observation length, site and management strategies in this population are not well established. Therefore, most recommendations are modeled after management of chronic overdose in patients with underlying medical conditions.

Objective: The primary objective of this study is to determine the frequency of acute toxicity after acute methotrexate accidental unsupervised ingestions in patients less than six years. In addition, we describe the frequency of late toxicity and characterize the management site and approaches.

Materials and Methods: This is a retrospective cohort study of pediatric accidental unsupervised methotrexate ingestions reported to six poison centers in the United States over a 16 year period. Demographic information, exposure details, signs, symptoms, treatments, length and location of observation and outcomes were collected.

Results: 103 patients met inclusion criteria. Methotrexate dose was reported in 86 patients (84%) and ranged from 1.3?mg–75?mg. The majority of cases (97%) ingested a dose ≤20?mg. The significant majority of cases experienced no clinical effects (99 of 103 cases; 96%). Three children experienced minor outcome (3%). There were no patients with a major outcome or death.

Conclusions: The incidence of toxicity from pediatric single, acute ingestions of methotrexate is rare and when it occurs is generally limited to no or only minimally concerning effects. Because concentrations from single ingestions were consistent with low subtoxic exposures, we believe that home monitoring without hospital referral and without methotrexate specific therapy is reasonable in those with acute ingestions up to 20?mg.     

Assessing Needs and Resources for the Home Visiting System in Alabama: A Mixed Methods Approach

The purpose of this article is to describe the initial assessment for the development of a home visiting (HV) system in a state with no existing system. We outline a mixed methods process where the quantitative component was used to identify the communities that possess “at-risk” profiles, and the qualitative component explored the resources and gaps in existing HV services. We employed a mixed methods approach, using six categories of indicators from quantitative secondary data sources to identify “at-risk” profiles for Alabama’s 67 counties. A weighted score for each indicator was calculated and counties were ranked. Surveys and focus groups were conducted to further define resources and gaps of existing HV programs. The composite indicator scores identified 13 counties as having the highest level of risk. Five of these 13 communities had no HV home visitation services. Areas of focus for future HV system development include trust, communication, availability, cost, and timeliness. In this assessment related to the Alabama HV system, we used quantitative data to apply criteria to the indicators being measured and qualitative data to supplement the quantitative findings. We examined resources, gaps, program quality, and capacity of the existing HV programs in order to assist in the future development of the HV system and early childhood system. The methods presented in this paper have potential applications beyond HV programs and systems, including broader examinations of complex systems for service provision to the maternal and child health populations.     

Spatial Variability of Metal Bioaccumulation in Estuarine Killifish (Fundulus heteroclitus) at the Callahan Mine Superfund Site, Brooksville, ME

The former Callahan Mine Site in Brooksville, ME, is an open-pit, hardrock mine site in an intertidal system, thus providing a unique opportunity to evaluate how metal-enriched sediments and overlying water impact estuarine food webs. Copper, zinc, cadmium, and lead concentrations in sediment, whole water, and Atlantic killifish (Fundulus heteroclitus) were evaluated at sites in Goose Pond (GP; Callahan Mine Site) and at reference sites. The metal concentrations of sediment, water, and fish were spatially distinct and significantly greater at the mine site than in the reference estuary. Sediment concentrations were particularly elevated and were above probable effects levels for all four metals adjacent to the tailings pile. Even in this well-mixed system, water metal concentrations were significantly elevated adjacent to the tailings pile, and concentrations of Cu and Zn were above ambient water-quality criteria for chronic marine exposure. Neither organic matter in the sediment nor salinity or pH of the water explained the metal concentrations. Adjacent to the tailings pile, killifish metal body burdens were elevated and were significantly related to both sediment and aqueous concentrations. In conclusion, (1) the contaminated sediment and seepage from the tailings impoundment and waste rock pile no. 3 create a continual flux of metals into the water column, (2) the metals are bioavailable and bioconcentrating as evident in the killifish tissue concentrations, and (3) Callahan Mine is directly affecting metal bioaccumulation in fauna residing in the GP estuary and, potentially, in Penobscot Bay by the way of “trophic nekton relay.”     

Gastrointestinal Mucositis: The Role of MMP-Tight Junction Interactions in Tissue Injury

Chemotherapy for cancer causes significant gut toxicity known as mucositis. The pathogenesis of mucositis is ill defined. Recent clinical research guidelines have highlighted epithelial junctional complexes as emerging targets within mucositis research. Given the robust biological evidence linking tight junctions and matrix metalloproteinases, key mediators of mucositis, tight junction proteins have received significant attention. Despite this, the link between tight junctions, matrix metalloproteinases and mucositis development is yet to be established. This critical review therefore aims to describe the role of matrix metalloproteinases in mucositis, and how matrix metalloproteinase-dependent tight junction disruption may contribute to the pathobiology of mucositis.