Can natural selection favour altruism between species?

Darwin suggested that the discovery of altruism between species would annihilate his theory of natural selection. However, it has not been formally shown whether between-species altruism can evolve by natural selection, or why this could never happen. Here, we develop a spatial population genetic model of two interacting species, showing that indiscriminate between species helping can be favoured by natural selection. We then ask if this helping behaviour constitutes altruism between species, using a linear-regression analysis to separate the total action of natural selection into its direct and indirect (kin selected) components. We show that our model can be interpreted in two ways, as either altruism within species, or altruism between species. This ambiguity arises depending on whether or not we treat genes in the other species as predictors of an individual's fitness, which is equivalent to treating these individuals as agents (actors or recipients). Our formal analysis, which focuses upon evolutionary dynamics rather than agents and their agendas, cannot resolve which is the better approach. Nonetheless, because a within-species altruism interpretation is always possible, our analysis supports Darwin's suggestion that natural selection does not favour traits that provide benefits exclusively to individuals of other species.

Biliary epithelial senescence and plasticity in acute cellular rejection

Biliary epithelial cells (BEC) are important targets in some liver diseases, including acute allograft rejection. Although some injured BEC die, many can survive in function compromised states of senescence or phenotypic de-differentiation. This study was performed to examine changes in the phenotype of BEC during acute liver allograft rejection and the mechanism driving these changes. Liver allograft sections showed a positive correlation (p < 0.0013) between increasing T cell mediated acute rejection and the number of BEC expressing the senescence marker p21(WAF1/Cip) or the mesenchymal marker S100A4. This was modeled in vitro by examination of primary or immortalized BEC after acute oxidative stress. During the first 48 h, the expression of p21(WAF1/Cip) was increased transiently before returning to baseline. After this time BEC showed increased expression of mesenchymal proteins with a decrease in epithelial markers. Analysis of TGF-β expression at mRNA and protein levels also showed a rapid increase in TGF-β2 (p < 0.006) following oxidative stress. The epithelial de-differentiation observed in vitro was abrogated by pharmacological blockade of the ALK-5 component of the TGF-β receptor. These data suggest that stress induced production of TGF-β2 by BEC can modify liver allograft function by enhancing the de-differentiation of local epithelial cells.

TNFα from classically activated macrophages accentuates epithelial to mesenchymal transition in obliterative bronchiolitis

Bronchiolitis obliterans syndrome is characterized by fibrotic obliteration of small airways which severely impairs graft function and survival after lung transplantation. Bronchial epithelial cells from the transplanted lung can undergo epithelial to mesenchymal transition and this can be accentuated by activated macrophages. Macrophages demonstrate significant plasticity and change phenotype in response to their microenvironment. In this study we aimed to identify secretory products from macrophages that might be therapeutic targets for limiting the inflammatory accentuation of epithelial to mesenchymal transition in bronchiolitis obliterans syndrome. TNFα, IL-1β and IL-8 are elevated in bronchoalveolar lavage from lung transplant patients prior to diagnosis of bronchiolitis obliterans syndrome. Classically activated macrophages secrete more TNFα and IL-1β than alternatively activated macrophages and dramatically accentuate TGF-β1-driven epithelial to mesenchymal transition in bronchial epithelial cells isolated from lung transplant patients. Blocking TNFα, but not IL-1β, inhibits the accentuation of epithelial to mesenchymal transition. In a pilot unblinded therapeutic intervention in five patients with progressive bronchiolitis obliterans syndrome, anti-TNFα treatment improved forced expiratory volume in 1 second and 6-min walk distances in four patients. Our data identify TNFα as a potential new therapeutic target in bronchiolitis obliterans syndrome deserving of a randomized placebo controlled clinical trial.

Important co-morbidity in patients with diabetes mellitus in three clinics in Western Kenya

SETTING

Diabetes clinics in three hospitals in Western Kenya: Moi Teaching and Referral Hospital and two associated district hospitals.

OBJECTIVE

To determine the proportion of diabetes patients with a history of tuberculosis (  TB), human immunodeficiency virus (HIV  ) infection and tobacco smoking.

DESIGN

A descriptive study using routinely collected data from patient records in the three diabetes clinics.

RESULTS

Of 1376 patients analyzed, 750 (55%) were female. The mean age of the patients in the clinics was 53.5 years (95%CI 52.2-54.8), with an average duration of diabetes of 8.1 years (95%CI 7.6-8.7). Of all patients, 5.6% reported a history of TB, similar to the frequency about 20 years earlier (1990) in Tanzania. Only 30% of the patients reported knowing their HIV status; 6% were HIV-positive. A history of tobacco smoking was reported by 3.8% of the patients.

CONCLUSION

The HIV epidemic does not seem to have significantly changed the relationship between TB and diabetes mellitus (DM) in this cohort of diabetes patients. The frequency of HIV and TB in this special population was comparable to that in the general population, and only a small proportion of patients reported a history of tobacco smoking.

Experiences in implementation of routine human immunodeficiency virus testing in a US tuberculosis clinic

SETTING

Rhode Island Tuberculosis (RI TB) Clinic, The Miriam Hospital, Providence, RI, USA.

BACKGROUND

Human immunodeficiency virus (HIV) status is a critical factor in the management of both patients with latent TB infection (LTBI) and active TB. Since 2006, the Centers for Disease Control and Prevention has recommended routine, opt-out HIV testing in all health care settings, including TB clinics. However, implementation of HIV testing in LTBI patients has been limited.

DESIGN

A policy for HIV assessment of all new patients was instituted at the RI TB Clinic. Patients who reported no HIV testing in the preceding year were offered opt-out HIV testing. Patient records (June 2010-June 2011) were retrospectively reviewed. Structured nursing interviews assessed staff acceptance.

RESULTS

A total of 821 (77.5%) first-visit TB patients underwent HIV status assessment: 96.3% of those not tested in the previous year agreed to testing; 65.9% of tests were performed at point of care. There was one new HIV diagnosis.

CONCLUSION

Implementing routine opt-out HIV testing in the RI TB Clinic is feasible, with high staff acceptance rates and low patient refusal rates. Perceived health systems barriers can be overcome. Incorporating opt-out HIV testing for LTBI patients expands testing opportunities to individuals unaware of their HIV status, and can identify HIV-infected patients early in the course of infection.

Goodness-of-fit measures for individual-level models of infectious disease in a Bayesian framework

In simple models there are a variety of tried and tested ways to assess goodness-of-fit. However, in complex non-linear models, such as spatio-temporal individual-level models, less research has been done on how best to ascertain goodness-of-fit. Often such models are fitted within a Bayesian statistical framework, since such a framework is ideally placed to account for the many areas of data uncertainty. Within a Bayesian context, a major tool for assessing goodness-of-fit is the posterior predictive distribution. That is, a distribution for a test statistic is found through simulation from the posterior distribution and then compared with the observed test statistic for the data. Here, we examine different test statistics and ascertain how well they can detect model misspecification via a simulation study.

Evolution of maternal care in diploid and haplodiploid populations

Maternal care has been suggested to evolve more readily in haplodiploid populations. Because maternal care appears to have been a prerequisite for the evolution of eusociality, this effect potentially explains the apparent preponderance of haplodiploidy among eusocial taxa. Here, I use a kin selection approach to model the evolution of maternal care in diploid and haplodiploid populations. In contrast to previous suggestions, I find that haplodiploidy may inhibit as well as promote the evolution of maternal care. Moreover, I find that the haplodiploidy effect vanishes in outbred populations if gene effects average rather than add together. I confirm these analytical results using numerical simulation of an explicit population genetics model. This analysis casts doubt upon the idea that haplodiploidy has promoted the evolution of maternal care and, consequently, the evolution of eusociality.

Community-based treatment of multidrug-resistant tuberculosis: early experience and results from Western Kenya

BACKGROUND

In the light of the 2010 World Health Organization estimation of 650 000 cases of multidrug-resistant tuberculosis (MDR-TB) globally, the need to develop, implement and scale up MDR-TB treatment programs is clear. The need is greatest and urgent in resource-poor countries, such as Kenya, with a high TB burden and an anticipated rise in reported cases of MDR-TB with increasing access to drug susceptibility testing.

OBJECTIVES

To describe the set-up of a community-based program, early clinical outcomes, challenges and possible solutions.

SETTING

The Moi Teaching and Referral Hospital (Moi Hospital) catchment areas: Western and North Rift Provinces, Kenya.

DESIGN

Program description and retrospective chart review.

RESULTS

An MDR-TB team established a community-based program with either home-based DOT or local facility-based DOT. Following referral, the team instituted a home visit, identified and hired a DOT worker, trained family and local health care professionals in MDR-TB care and initiated community-based MDR-TB treatment. In the first 24 months, 14 patients were referred, 5 died prior to initiation of treatment and one had extensively drug-resistant TB. Among eight patients who initiated community-based DOT, 87% underwent culture conversion by 6 months, and 75% were cured with no relapse after a median follow-up of 15.5 months. Multiple challenges were experienced, including system delays, stigma and limited funding.

CONCLUSION

Despite multiple challenges, our model of an MDR-TB team that establishes a community-based treatment system encircling diagnosed cases of MDR-TB is feasible, with acceptable treatment outcomes.

Anaesthesia trainees' exposure to regional anaesthesia in an Australian tertiary adult teaching hospital

The purpose of this study was to quantify the exposure of anaesthetic trainees to regional anaesthesia in an Australian tertiary adult teaching hospital. We reviewed data collected on all regional blocks performed by the anaesthetic department over a two-year period. The data was then broken down to give an estimate of the number of each block performed by each training year group. There was an average of 27.7 full-time equivalent trainees attached to the department. Trainees performed a total of 1374 blocks over this period. The average number of blocks performed by basic training year one trainees each year was 6.5, basic training year two trainees 13.5, advanced training year one trainees 14.9, advanced training year two trainees 19.1, advanced training year three trainees 23.1 and regional fellows 144.0. The number of total blocks and the proportion of advanced blocks increased with increasing level of training while supervision declined. Trainees in the two regional fellowship positions (7% of the trainee pool) performed 42% of the 1374 blocks. Factors that may influence the exposure of trainees to regional anaesthesia and the assessment of competency are considered.

Repression of competition favours cooperation: experimental evidence from bacteria

Repression of competition (RC) within social groups has been suggested as a key mechanism driving the evolution of cooperation, because it aligns the individual's proximate interest with the interest of the group. Despite its enormous potential for explaining cooperation across all levels of biological organization, ranging from fair meiosis, to policing in insect societies, to sanctions in mutualistic interactions between species, there has been no direct experimental test of whether RC favours the spread of cooperators in a well-mixed population with cheats. To address this, we carried out an experimental evolution study to test the effect of RC upon a cooperative trait - the production of iron-scavenging siderophore molecules - in the bacterium Pseudomonas aeruginosa. We found that cooperation was favoured when competition between siderophore producers and nonsiderophore-producing cheats was repressed, but not in a treatment where competition between the two strains was permitted. We further show that RC altered the cost of cooperation, but did not affect the relatedness among interacting individuals. This confirms that RC per se, as opposed to increased relatedness, has driven the observed increase in bacterial cooperation.

Translaminar screw fixation of a kyphosis of the cervical and thoracic spine in neurofibromatosis

The spinal manifestations of neurofibromatosis include cervicothoracic kyphosis, in which scalloping of the vertebral body and erosion of the pedicles may render conventional techniques of fixation impossible. We describe a case of cervicothoracic kyphosis managed operatively with a vascularised fibular graft anteriorly across the apex of the kyphus, followed by a long posterior construct using translaminar screws, which allow segmental fixation in vertebral bodies where placement of the pedicle screws was impracticable.

Improvements in cognition, mood and behaviour following commencement of continuous subcutaneous insulin infusion therapy in children with type 1 diabetes mellitus: a pilot study

AIMS/HYPOTHESIS

Anecdotally, parents and teachers of children with type 1 diabetes mellitus report improvements in behaviour and learning following the commencement of continuous subcutaneous insulin infusion (CSII). This study aimed to investigate changes in cognition, mood and behaviour following commencement of CSII in children with type 1 diabetes.

METHODS

Children (n = 32) with type 1 diabetes aged 6-16 years and starting CSII at two Australian centres underwent behavioural, cognitive and glycaemic assessments prior to the commencement of CSII and 6-8 weeks after its start. A comprehensive cognitive test battery was administered, comprising measures of intelligence, attention, processing speed and executive skills. Behaviour and mood were assessed using the Behaviour Assessment System for Children--Second Edition. Continuous glucose monitoring was performed over a 72 h period and HbA(1c) was measured at both time-points.

RESULTS

After commencement of CSII, there were significant improvements in HbA(1c), a reduction in hyperglycaemia and blood glucose variation and an increase in normoglycaemia. Significant improvements were observed in perceptual reasoning, selective attention, divided attention, cognitive flexibility and working memory. Fewer mood-related symptoms were reported (parent, teacher and self-report) and fewer behavioural problems (parent reports)

CONCLUSIONS/INTERPRETATION

In this uncontrolled pilot study, children with type 1 diabetes demonstrated significant improvements in measures of metabolic control, mood and behaviour and in some complex cognitive skills after commencing CSII therapy.

Capturing the superorganism: a formal theory of group adaptation

Adaptation is conventionally regarded as occurring at the level of the individual organism. However, in recent years there has been a revival of interest in the possibility for group adaptations and superorganisms. Here, we provide the first formal theory of group adaptation. In particular: (1) we clarify the distinction between group selection and group adaptation, framing the former in terms of gene frequency change and the latter in terms of optimization; (2) we capture the superorganism in the form of a 'group as maximizing agent' analogy that links an optimization program to a model of a group-structured population; (3) we demonstrate that between-group selection can lead to group adaptation, but only in rather special circumstances; (4) we provide formal support for the view that between-group selection is the best definition for 'group selection'; and (5) we reveal that mechanisms of conflict resolution such as policing cannot be regarded as group adaptations.

Nice natives and mean migrants: the evolution of dispersal-dependent social behaviour in viscous populations

There has been much interest in the evolution of social behaviour in viscous populations. While low dispersal increases the relatedness of neighbours, which tends to promote the evolution of indiscriminate helping behaviour, it can also increase competition between neighbours, which tends to inhibit the evolution of helping and may even favour harming behaviour. In the simplest scenario, these two effects exactly cancel, so that dispersal rate has no impact on the evolution of helping or harming. Here, we show that dispersal rate does matter when individuals can adjust their social behaviour conditional on whether they have dispersed or whether they have remained close to their place of origin. We find that nondispersing individuals are weakly favoured to indiscriminately help their neighbours, whereas dispersing individuals are more readily favoured to indiscriminately harm their neighbours.

Evaluation of Nasopharyngeal Oxygen, Nasal Prongs and Facemask Oxygen Therapy Devices in Adult Patients: A Randomised Crossover Trial

Nasopharyngeal oxygen (NPO) therapy may overcome some of the difficulties associated with nasal prongs and facemask oxygen delivery devices. In response to a lack of published studies of NPO therapy in adults, we conducted a prospective randomised crossover trial to compare the effectiveness of NPO, nasal prongs (NP) and facemasks (FM) when used in an adult population (n=37) from the intensive care unit and general hospital wards. We measured oxygen saturation (SpO 2 using pulse oximetry, oxygen flow (litres per minute), respiration rate (per minute) and comfort using a horizontal visual analogue scale. All three devices were effective in maintaining a Sp0 2 of ≥95% (NP 97.0±1.9, NPO 97.7±1.7, FM 98.8±1.3%). NPO therapy consumed less oxygen than NP and FM therapy (NP 2.6±1.0, NPO 2.2±0.9, FM 6.1 ±0.4 l/min, P <0.001). There was no significant difference in patients’ respiratory rates (NP 19.9±3.2, NPO 19.9±3.0, FM 19.8±3.1 per minute, P=0.491). In terms of comfort, patients rated NP higher than NPO and FM using a horizontal visual analogue scale (100 mm=most comfortable) (NP 65.5±14.3, NPO 62.8±19.4, FM 49.4 ± 21.4 mm, P <0.001). We conclude that for adult patients, nasal prongs and nasopharyngeal oxygen therapy consume less oxygen and provide greater comfort than facemasks while still maintaining Sp0 2 ≥95%.