From mutation to mechanism: deciphering the molecular function of genetic variants linked to human ageing

Many of the leading causes of death in humans, such as cardiovascular disease, type 2 diabetes and Alzheimer’s disease are influenced by biological mechanisms that become dysregulated with increasing age. Hence, by targeting these ageing-related mechanisms, we may be able to improve health in old age. Ageing is partly heritable and genetic studies have been moderately successful in identifying genetic variants associated with ageing-related phenotypes (lifespan, healthspan and longevity). To decipher the mechanisms by which the identified variants influence ageing, studies that focus on their functional validation are vital. In this perspective, we describe the steps that could be taken in the process of functional validation: (1) in silico characterisation using bioinformatic tools; (2) in vitro characterisation using cell lines or organoids; and (3) in vivo characterisation studies using model organisms. For the in vivo characterisation, it is important to focus on translational phenotypes that are indicative of both healthspan and lifespan, such as the frailty index, to inform subsequent intervention studies. The depth of functional validation of a genetic variant depends on its location in the genome and conservation in model organisms. Moreover, some variants may prove to be hard to characterise due to context-dependent effects related to the experimental environment or genetic background. Future efforts to functionally characterise the (newly) identified genetic variants should shed light on the mechanisms underlying ageing and will help in the design of targeted interventions to improve health in old age

Extractibilityof Residual Rock and Superphosphate on Limed and Unlimed Bungor Soil.

The possibility of using soil extractants to monitor the transformation of phosphorus (P) fertilizer on a Bungor series soil was investigated. Three soil extractants - Bray 2, Ammonium acetate lactate (AAL) and Olsen - were evaluated. The soil was treated with three levels of P each from rock phosphate and superphosphate at 0, 150 and 300kg Plha, no lime and limed at 4 tons/ha and a P fertilizer application interval of one year. Bray 2 and AAL were able to detect recent P from aged P applications with a higher amount of P being extracted from the recent. These extracts were able to differentiate between the 150 and 300kg Plha treatments but were not able to distinguish the forms of P. Olsen extractant on the other hand was able to detect the two P forms and showed P release from rock phosphate with time

Genetic and biomarker studies of human longevity

The aim of this thesis was to identify novel lifespan regulating loci that influence human longevity and population mortality. To this end, we performed two genome-wide association studies, one of long-lived individuals from the family-based Leiden Longevity Study (LLS) and an extended one of long-lived individuals from multiple cohorts of European descent. Using the latter, we identified two genome-wide significant loci, the TOMM40/APOE/APOC1 locus and an intergenic locus on chromosome 5q33.3. In addition, our gene set analysis with the LLS data showed that genetic variation in genes involved in the insulin/IGF-1 signaling and telomere maintenance pathways is associated with human longevity. Since our genetic studies identified a limited number of longevity loci, we additionally examined whether leukocyte telomere length (LTL) could be used as a biomarker of healthy aging. We showed that LTL meets three of the four criteria for a biomarker of healthy aging in the LLS, i.e., LTL changes with chronological age and is associated with health, in this case immune-related parameters, and prospective mortality. To identify novel longevity loci, future research may benefit from a better definition of the healthy aging phenotype, combining study designs, and the use of novel methods and technologies, such as next-generation sequencing.Netherlands Consortium for Healthy Ageing (NGI 050-060-810)UBL - phd migration 201

Handling End-of-Life Situations in Small Animal Practice:What Strategies do Veterinarians Contemplate During their Decision-Making Process?

This study researched end-of-life (EoL) decision-making processes in small animal practices in the Netherlands, focusing on strategies veterinarians contemplate during this process. Fourteen veterinarians were interviewed about animal end-of-life decision-making. The results of these interviews show that the decision-making process consists of three steps. The first step is to assess the animal’s health and welfare. During the second step, veterinarians consider the position of the owner. Based on steps 1 and 2, veterinarians decide in step 3 whether their advice is to a) euthanize or b) contemplate one or more strategies to come to a decision or potentially alter the decision. These results can support members of the veterinary profession to reflect on their decision-making process. If veterinarians know what strategies their peers use to deal with EoL situations, this can help to reduce the stress they experience in such situations. In addition, veterinarians may find inspiration for new strategies in the study results. For the veterinary profession itself, the current results can be used as a starting point for describing best practices for EoL decision-making in small animal practice.</p

Contraceptive Efficacy of a Novel Intrauterine Device (IUD) in White-Tailed Deer

Overabundant white-tailed deer (Odocoileus virginianus) pose risks to property, health, and safety of human beings. Public concerns about lethal management can impair efforts to address these issues, particularly in urban settings. Several techniques developed for reducing reproductive output of deer have limited utility because they require repeated dosing to achieve permanent effect and face uncertain regulatory approval for use beyond experimentation. From 10 August 2006 through 30 December 2007, we evaluated the contraceptive efficacy of copper-containing intrauterine devices (IUDs) implanted trans-cervically in white-tailed deer at the E.S. George Reserve in Pinckney, Michigan. Intrauterine devices were implanted before (n = 9) and shortly after (n = 10) the breeding season. Post-breeding season IUD treatment was in conjunction with a 5 cm3 dose of 5 mg/ml prostaglandin F2α (PGF2α), delivered subcutaneously. Intrauterine devices reduced pregnancy rates when administered prior to breeding (P \u3c 0.001) and prevented pregnancy for up to 2 years (the duration of the study). Two of 8 does that received IUDs prior to the breeding season and survived to the end of the study became pregnant (due to loss of the implant) during the second year while all (n = 16) does without implants conceived. Cervical changes associated with early pregnancy made trans-cervical implantation after the breeding season challenging, and resulted in improperly placed IUDs in 2 treated does. The apparent expulsion of IUDs by pregnant does that received the combined treatment after breeding suggests IUD treatment should be limited to the pre-breeding season. Intrauterine devices show potential as a tool for small-scale deer population management via non-steroidal reproductive inhibition

Considering life and death:a qualitative vignette study among farm animal veterinarians in the Netherlands on considerations in end-of-life decision-making

Farm animal veterinarians are frequently involved in animals’ end-of-life (EoL) situations. Existing literature found that the decision-making process to end an animal’s life can be experienced as complex and stressful by veterinarians. The complexity of the process may find its origin in the multiple medical and non-medical aspects that veterinarians consider coming to their decision. Although research provides insight into what considerations are at stake, the literature does not provide information on how these aspects affect the decision-making process. This study explores how different considerations affect the decision-making process of farm animal veterinarians in EoL situations. Semi-structured interviews were conducted with nineteen farm animal veterinarians in the Netherlands. During the interviews, case scenarios in the form of vignettes were used to identify and explore the considerations that play a role for these veterinarians in EoL decision-making. Based on the analysis of the interview data, we discovered that farm animal veterinarians consider EoL situations using one of three identified frames: function, prospect, and duty. These frames illustrate one’s perspective on the interplay of medical and non-medical aspects. Whereas veterinarians for whom the function frame is dominant focus on the human-centred function that an animal fulfils, veterinarians for whom the prospect frame is dominant focus on an animal’s prospects based on the animal’s living conditions and the influence of the owner. Veterinarians for whom the duty frame is dominant focus on the owner’s legal position towards the animal, illustrating a clear distinction between the veterinarian’s professional duties towards the animal and the duty of care of the animal owner. As such, the key contributions of this study are the discovery of the importance of the interplay between considerations in EoL decision-making and the frame-specific approach of veterinarians. The identified frames may relate to the coping strategies of veterinarians dealing with the complexity of EoL situations.</p

Considering life and death:a qualitative vignette study among farm animal veterinarians in the Netherlands on considerations in end-of-life decision-making

Farm animal veterinarians are frequently involved in animals’ end-of-life (EoL) situations. Existing literature found that the decision-making process to end an animal’s life can be experienced as complex and stressful by veterinarians. The complexity of the process may find its origin in the multiple medical and non-medical aspects that veterinarians consider coming to their decision. Although research provides insight into what considerations are at stake, the literature does not provide information on how these aspects affect the decision-making process. This study explores how different considerations affect the decision-making process of farm animal veterinarians in EoL situations. Semi-structured interviews were conducted with nineteen farm animal veterinarians in the Netherlands. During the interviews, case scenarios in the form of vignettes were used to identify and explore the considerations that play a role for these veterinarians in EoL decision-making. Based on the analysis of the interview data, we discovered that farm animal veterinarians consider EoL situations using one of three identified frames: function, prospect, and duty. These frames illustrate one’s perspective on the interplay of medical and non-medical aspects. Whereas veterinarians for whom the function frame is dominant focus on the human-centred function that an animal fulfils, veterinarians for whom the prospect frame is dominant focus on an animal’s prospects based on the animal’s living conditions and the influence of the owner. Veterinarians for whom the duty frame is dominant focus on the owner’s legal position towards the animal, illustrating a clear distinction between the veterinarian’s professional duties towards the animal and the duty of care of the animal owner. As such, the key contributions of this study are the discovery of the importance of the interplay between considerations in EoL decision-making and the frame-specific approach of veterinarians. The identified frames may relate to the coping strategies of veterinarians dealing with the complexity of EoL situations.</p

An International Prospective Cohort Study To Validate 2 Prediction Rules for Infections Caused by Third-generation Cephalosporin-resistant Enterobacterales

Background The possibility of bloodstream infections caused by third-generation cephalosporin-resistant Enterobacterales (3GC-R-BSI) leads to a trade-off between empiric inappropriate treatment (IAT) and unnecessary carbapenem use (UCU). Accurately predicting 3GC-R-BSI could reduce IAT and UCU. We externally validate 2 previously derived prediction rules for community-onset (CO) and hospital-onset (HO) suspected bloodstream infections. Methods In 33 hospitals in 13 countries we prospectively enrolled 200 patients per hospital in whom blood cultures were obtained and intravenous antibiotics with coverage for Enterobacterales were empirically started. Cases were defined as 3GC-R-BSI or 3GC-R gram-negative infection (3GC-R-GNI) (analysis 2); all other outcomes served as a comparator. Model discrimination and calibration were assessed. Impact on carbapenem use was assessed at several cutoff points. Results 4650 CO infection episodes were included and the prevalence of 3GC-R-BSI was 2.1% (n = 97). IAT occurred in 69 of 97 (71.1%) 3GC-R-BSI and UCU in 398 of 4553 non–3GC-R-BSI patients (8.7%). Model calibration was good, and the AUC was .79 (95% CI, .75–.83) for 3GC-R-BSI. The prediction rule potentially reduced IAT to 62% (60/97) while keeping UCU comparable at 8.4% or could reduce UCU to 6.3% (287/4553) while keeping IAT equal. IAT and UCU in all 3GC-R-GNIs (analysis 2) improved at similar percentages. 1683 HO infection episodes were included and the prevalence of 3GC-R-BSI was 4.9% (n = 83). Here model calibration was insufficient. Conclusions A prediction rule for CO 3GC-R infection was validated in an international cohort and could improve empirical antibiotic use. Validation of the HO rule yielded suboptimal performance

Copy number variation associates with mortality in long-lived individuals:a genome-wide assessment

Pathophysiology, epidemiology and therapy of agein