The effect of the visual exercise environment on the response to psychological stress: a pilot study.

Background: Performing physical activity whilst exposed to nature can improve health. However, there is little evidence of its impact on stress outcomes. The aim of this study was to examine the influence of the visual exercise environment on the response to a psychosocial stressor. Methods: Eighteen participants were randomized to one of three conditions: i. nature; ii. built or; iii. control condition. Participants exercised for 30 min on a treadmill at 50% of their VO2max whilst viewing a video of either a natural or built environment or a blank screen. Following the exercise, participants completed the Trier Social Stress Test (TSST), a standardized laboratory stressor. Salivary samples were collected before, during and after the TSST to calculate cortisol reactivity and recovery. Results: One-way ANOVA revealed a significant effect of viewing condition on cortisol reactivity [F(2, 11) = 4.686, p = .034; n2p = .460]; with significantly lower reactivity in the built compared to the nature condition (p = .027, d = 1.73). There was no effect of condition on cortisol recovery (p = .137; n2p = .257). Conclusions: In the context of the adverse health impact of lower (i.e., blunted) cortisol responding, these findings could indicate a negative impact of the built environment on stress responses.

The health impact of nature exposure and green exercise across the life course: a pilot study.

BACKGROUND: Both nature exposure and green exercise (GE) provide numerous health benefits. However, there are no studies examining the impact of childhood GE on adult health. METHODS: 45 healthy adults (aged 69.8 ± 8.4 years) took part in the study, wearing a Firstbeat heart rate variability (HRV) monitor for 24 hours. Participants also completed questionnaires assessing childhood and adulthood nature exposure and GE, as well as current connectedness to nature (CN), perceived stress and well-being. Pearson's correlations and linear regression were used to examine relationships between variables. RESULTS: Childhood nature exposure and GE significantly predicted adult nature exposure and GE (ß .317, p < 0.05) as well as CN (ß = .831, p < 0.01). After controlling for childhood nature exposure and GE, CN was negatively associated with the percentage of stress over the 24-hour period (r = -.363; p < 0.05) and positively associated with HRV during sleep (r = .415; p < 0.05). CONCLUSIONS: CN is important for adult health; however childhood nature exposure and GE are essential to developing this connection.

Self-similar evolution in nonlocal nonlinear media.

The self-similar propagation of optical beams in a broad class of nonlocal, nonlinear optical media is studied utilizing a generic system of coupled equations with linear gain. This system describes, for instance, beam propagation in nematic liquid crystals and optical thermal media. It is found, both numerically and analytically, that the nonlocal response has a focusing effect on the beam, concentrating its power around its center during propagation. In particular, the beam narrows in width and grows in amplitude faster than in local media, with the resulting beam shape being parabolic. Finally, a general initial localized beam evolves to a common shape.

Attenuated cortisol reactivity to psychosocial stress is associated with greater visual dependency in postural control.

Despite known anatomical links between the hypothalamic-pituitary-adrenal (HPA) axis and the vestibular system, there are no studies on the relationship between postural control and HPA axis function. Visual dependence in postural control, often measured by increased postural sway on exposure to visual motion, is an indication of altered visual-vestibular integration with greater weighting towards visual cues for balance. Visual dependence is more common in older age and a range of vestibular and non-vestibular health conditions. The relationship between visual dependence in postural control was investigated in relation to cortisol reactivity to psychosocial stress (using the Trier Social Stress Test for groups: TSST-G), as an index of HPA axis function, in healthy young females. In those who exhibited a cortisol response (>2 nmol/l), a negative relationship between stress-induced cortisol reactivity and visual dependence in postural control was observed, since those with the largest cortisol response showed less visual motion induced postural sway (measured by force platform). This finding in healthy females indicates that subtle non-clinical differences in vestibular function are associated with dysregulated HPA axis activity as indicated by lower cortisol reactivity to psychosocial stress. It adds to the growing body of evidence linking blunted cortisol reactivity to stress to poor homeostatic regulation and potential negative health and behavioural outcomes.

Salience versus magnitude in the measurement of the cortisol awakening response.

Pulsatile ultradian secretion of cortisol, rarely studied in salivary data, has functional importance in hypothalamic pituitary adrenal (HPA) axis regulation. The first daily ultradian episode, the cortisol awakening response (CAR), was examined in healthy adults, in 5-min secretion rates of salivary cortisol from electronically monitored awakening time to 1.25 h. Aggregated rates revealed a cubic trend, with wave-length of almost exactly 1 h, as predicted from known ultradian periodicity. Peak secretion rate occurred 20-min post-awakening. Peak (20-min) to trough (59-min) amplitude (PTA) expressed a salient signal shape. Rates rose steeply to and from peak, and major secretion was packaged into a few 5-min intervals, inconsistent with normal or uniform distribution of 5-min rates, but consistent with known pulsatile cortisol delivery. Null hypotheses asserting normal or uniform distributions were rejected. Maximal rates overwhelmingly occurred before and minimal rates after 30-mins, with degree of extremity at each polarity significantly positively correlated. To demonstrate utility and reliability of PTA estimation in a clinically relevant domain, re- analyses of a previously published study were conducted. Data from only three saliva samples were used, given importance of cost considerations for many CAR researchers. Difference between mean rates before and after 30-min yielded a simple salience index, highly correlated with PTA derived from full 5-min interval data. CAR salience performed significantly better than traditional AUCi magnitude in discriminating control cases (higher inferred amplitude) and cases with Seasonal Affective Disorder (lower inferred amplitude). Evidence suggested that low AUCi may be more sensitive in identifying within-subject changes (e.g. more depressed mood in winter among SAD cases) and low CAR salience better at revealing enduring between-subjects associations (e.g. underlying disorder vulnerability). Since both PTA salience and AUCi magnitude can be analysed and compared using exactly the same data from the same commonly used saliva sampling points, further research is warranted into the importance of individual differences in patterns of cortisol delivery, not just how much is delivered.

Repressors exhibit lower cortisol reactivity to group psychosocial stress.

Repressors are well-known to monitor potential psychosocial threats to their self-esteem and self-concept. In research, repressors are traditionally categorised as those scoring low on trait anxiety and high on defensiveness (as measured by social desirability scales). Examining repressors' cortisol reactivity to a group socio-evaluative laboratory stressor could be an important way to extend work on the classic 'repressor dissociation', which proposes that this group experience higher levels of physiological stress, but lower levels of subjective affect, during stressful situations. Research however has focused mainly on repressors' higher, more risk-prone levels of autonomic, rather than hypothalamic-pituitary-adrenal (HPA), reactivity to stressful stimuli. We assessed cortisol reactivity using a group-based acute psychosocial stressor, the Trier Social Stress Test for groups (TSST-G), which required participants to individually perform public speaking and mental arithmetic tasks in front of up to six other group members, as well as an evaluative panel of judges. Seventy-seven healthy young females (mean age ± SD: 20.2 ± 3.2 years) took part, of which 64 met the conventional criterion for a response to the TSST-G (<15.5% increase from baseline sample). The Stress-Arousal Checklist was completed pre- and post-TSST-G. Participants also completed the Perceived Stress Scale, the Trait Anxiety Inventory and the Marlow-Crowne Social Desirability Scale. The latter two measures were used to provide a categorisation of repressive coping style. Participants identified as repressive copers exhibited significantly lower cortisol reactivity during the TSST-G. Repressors also self-reported less subjective stress. These findings provide some evidence against the notion of the repressor dissociation and are discussed in terms of how cortisol hyporeactivity may be a pathway through which repressive coping adversely affects health.

Advanced maternal age causes adverse programming of mouse blastocysts leading to altered growth and impaired cardiometabolic health in post-natal life.

STUDY QUESTION: Does advanced maternal age (AMA) in mice affect cardiometabolic health during post-natal life in offspring derived from an assisted reproduction technology (ART) procedure? SUMMARY ANSWER: Offspring derived from blastocysts collected from aged female mice displayed impaired body weight gain, blood pressure, glucose metabolism and organ allometry during post-natal life compared with offspring derived from blastocysts from young females; since all blastocysts were transferred to normalized young mothers, this effect is independent of maternal pregnancy conditions. WHAT IS KNOWN ALREADY: Although studies in mice have shown that AMA can affect body weight and behaviour of offspring derived from natural reproduction, data on the effects of AMA on offspring cardiometabolic health during post-natal development are not available. Given the increasing use of ART to alleviate infertility in women of AMA, it is pivotal to develop ART-AMA models addressing the effects of maternal aging on offspring health. STUDY DESIGN, SIZE, DURATION: Blastocysts from old (34-39 weeks) or young (8-9 weeks) C57BL/6 females mated with young CBA males (13-15 weeks) were either subjected to differential cell staining (inner cell mass and trophectoderm) or underwent embryo transfer (ET) into young MF1 surrogates (8-9 weeks) to produce young (Young-ET, 9 litters) and old (Old-ET, 10 litters) embryo-derived offspring. Offspring health monitoring was carried out for 30 weeks. PARTICIPANTS/MATERIALS, SETTING, METHODS: All animals were fed with standard chow. Blood pressure was measured at post-natal Weeks 9, 15 and 21, and at post-natal Week 30 a glucose tolerance test (GTT) was performed. Two days after the GTT mice were killed for organ allometry. Blastocyst cell allocation variables were evaluated by T-test and developmental data were analysed with a multilevel random effects regression model. MAIN RESULTS AND THE ROLE OF CHANCE: The total number of cells in blastocysts from aged mice was decreased (P < 0.05) relative to young mice due to a lower number of cells in the trophectoderm (mean ± SEM: 34.5 ± 2.1 versus 29.6 ± 1.0). Weekly body weight did not differ in male offspring, but an increase in body weight from Week 13 onwards was observed in Old-ET females (final body weight at post-natal Week 30: 38.5 ± 0.8 versus 33.4 ± 0.8 g, P < 0.05). Blood pressure was increased in Old-ET offspring at Weeks 9-15 in males (Week 9: 108.5 ± 3.13 versus 100.8 ± 1.5 mmHg, Week 15: 112.9 ± 3.2 versus 103.4 ± 2.1 mmHg) and Week 15 in females (115.9 ± 3.7 versus 102.8 ± 0.7 mmHg; all P < 0.05 versus Young-ET). The GTT results and organ allometry were not affected in male offspring. In contrast, Old-ET females displayed a greater (P < 0.05) peak glucose concentration at 30 min during the GTT (21.1 ± 0.4 versus 17.8 ± 1.16 mmol/l) and their spleen weight (88.2 ± 2.6 ± 105.1 ± 4.6 mg) and several organ:body weight ratios (g/g × 10(3)) were decreased (P < 0.05 versus Young-ET), including the heart (3.7 ± 0.06 versus 4.4 ± 0.08), lungs (4.4 ± 0.1 versus 5.0 ± 0.1), spleen (2.4 ± 0.06 versus 3.2 ± 0.1) and liver (36.4 ± 0.6 versus 39.1 ± 0.9). LIMITATIONS, REASONS FOR CAUTION: Results from experimental animal models cannot be extrapolated to humans. Nevertheless, they are valuable to develop conceptual models that can produce hypotheses for eventual testing in the target species (i.e. humans). WIDER IMPLICATIONS OF THE FINDINGS: Our data show that offspring from mouse embryos from aged mothers can develop altered phenotypes during post-natal development compared with embryos from young mothers. Because all embryos were transferred into young mothers for the duration of pregnancy to normalize the maternal in vivo environment, our findings indicate that adverse programming via AMA is already established at the blastocyst stage. Whilst human embryos display increased aneuploidy compared with mouse, we believe our data have implications for women of AMA undergoing assisted reproduction, including surrogacy programmes. STUDY FUNDING/COMPETING INTERESTS: This work was supported through the European Union FP7-CP-FP Epihealth programme (278418) to T.P.F. and the BBSRC (BB/F007450/1) to T.P.F. The authors have no conflicts of interest to declare.

Osteochondral lesions of the talus: aspects of current management.

Osteochondral lesions (OCLs) occur in up to 70% of sprains and fractures involving the ankle. Atraumatic aetiologies have also been described. Techniques such as microfracture, and replacement strategies such as autologous osteochondral transplantation, or autologous chondrocyte implantation are the major forms of surgical treatment. Current literature suggests that microfracture is indicated for lesions up to 15 mm in diameter, with replacement strategies indicated for larger or cystic lesions. Short- and medium-term results have been reported, where concerns over potential deterioration of fibrocartilage leads to a need for long-term evaluation. Biological augmentation may also be used in the treatment of OCLs, as they potentially enhance the biological environment for a natural healing response. Further research is required to establish the critical size of defect, beyond which replacement strategies should be used, as well as the most appropriate use of biological augmentation. This paper reviews the current evidence for surgical management and use of biological adjuncts for treatment of osteochondral lesions of the talus.

A transatlantic survey of nutrition practice in acute pancreatitis.

BACKGROUND: Many guidelines exist for the nutritional management of acute pancreatitis; however, little is known regarding current practice. We aimed to investigate feeding practices, including the use of parenteral/enteral nutrition. METHODS: The study design was a cross-sectional, descriptive survey. Electronic surveys were sent to dietitians in the UK, the Republic of Ireland and Canada. Of 253 dietitians surveyed, 204 saw patients with acute pancreatitis regularly or occasionally and were included in the analyses. RESULTS: Most dietitians (92.8%) considered early feeding to mean <48 h after presentation. Over half (54.2%) favoured early feeding in severe disease, less in obesity (42%) and more with pre-existing malnutrition (81.9%). There was a tendency to feed earlier in university hospitals (P = 0.015), especially in obesity (P = 0.011). There was a tendency towards enteral (versus parenteral) nutrition in university hospitals (P = 0.000). The majority preferred the jejunal route (64.2%), although this was lower in the UK (43.8%) than in Canada (77.8%) or Ireland (54.2%). Under one-quarter of UK dietitians (23.2%) reported the existence of a pancreatic multidisciplinary team in their institutions, although this was lower in Ireland and Canada. CONCLUSIONS: Despite guidelines, there are gaps in the nutritional management of acute pancreatitis, including a continued reliance on parenteral feeding.

Tissue-specific selection of reference genes is required for expression studies in the mouse model of maternal protein undernutrition.

Suboptimal maternal nutrition during gestation results in the establishment of long-term phenotypic changes and an increased disease risk in the offspring. To elucidate how such environmental sensitivity results in physiological outcomes, the molecular characterisation of these offspring has become the focus of many studies. However, the likely modification of key cellular processes such as metabolism in response to maternal undernutrition raises the question of whether the genes typically used as reference constants in gene expression studies are suitable controls. Using a mouse model of maternal protein undernutrition, we have investigated the stability of seven commonly used reference genes (18s, Hprt1, Pgk1, Ppib, Sdha, Tbp and Tuba1) in a variety of offspring tissues including liver, kidney, heart, retro-peritoneal and inter-scapular fat, extra-embryonic placenta and yolk sac, as well as in the preimplantation blastocyst and blastocyst-derived embryonic stem cells. We find that although the selected reference genes are all highly stable within this system, they show tissue, treatment and sex-specific variation. Furthermore, software-based selection approaches rank reference genes differently and do not always identify genes which differ between conditions. Therefore, we recommend that reference gene selection for gene expression studies should be thoroughly validated for each tissue of interest.

Sustained TL1A expression modulates effector and regulatory T-cell responses and drives intestinal goblet cell hyperplasia.

The tumor necrosis factor (TNF) superfamily protein TNF-like 1A (TL1A) is the ligand for death receptor 3 (DR3). TL1A is induced on activated dendritic cells (DCs) and its expression has been linked to human inflammatory bowel disease. To address how TL1A might influence intestinal inflammation, we generated transgenic mice that constitutively express TL1A on DCs. TL1A transgenic mice developed striking goblet cell hyperplasia in the ileum that was associated with elevated interleukin (IL)-13 levels in the small intestine. IL-13- and IL-17-producing small intestinal lamina propria T cells were increased in TL1A transgenic mice. TL1A also enhanced regulatory T (Treg) cell turnover in vivo and directly stimulated Treg cell proliferation in vitro. The presence of TL1A attenuated the ability of Treg cells to suppress conventional T cells, an effect that required DR3 signaling in either conventional T cells or Treg cells. Our findings identify mechanisms by which chronic DR3 signaling could promote pathogenesis in inflammatory bowel disease.

Blind bedside insertion of small bowel feeding tubes.

BACKGROUND: The use of Naso-Jejunal (NJ) feeding is limited by difficulty in feeding tube placement. Patients have traditionally required transfer to Endoscopy or Radiology for insertion of small bowel feeding tubes, with clear resource implications. We hypothesised that the adoption of a simple bedside procedure would be effective and reduce cost. Clinical nutrition and nurse specialist personnel were trained in the 10/10/10 method of blind bedside NJ insertion. AIMS: The aims of this prospective study were to evaluate safety, efficaciousness and resource implications of bedside NJ tube insertion. METHODS: A total of 22 patients had 37 NJ tubes inserted in the study period (12 months). The majority were inserted by either a nurse specialist or clinical nutritionist. RESULTS: Out of the 37 insertions, 32 (86%) were in the correct position. Compared to Endoscopy insertion, this technique saved an estimated €8,353.60 for the duration of the study. CONCLUSION: This study demonstrates that the bedside insertion of NJ tubes by clinical nutritionists and nurse specialists is safe, efficacious and highly cost effective.

Undular bore solution of the Camassa-Holm equation.

Modulation theory is developed for a periodic peakon solution of the Camassa-Holm equation. An explicit simple wave solution of these modulation equations is then derived; this simple wave describing the evolution into an undular bore of an initial step. The characteristic on which the expansion fan occurs (propagating at a nonlinear group velocity) has a turning point, illustrating the fact that there is a minimum nonlinear group velocity at which the waves can propagate. A linear analytical solution, based on an integral of the Airy function, is then derived to describe the evanescent portion of the undular bore behind the turning point. Good agreement is found between the modulation theory plus Airy integral solution and numerical solutions.

Pulse evolution in nonlinear optical fibers with sliding-frequency filters.

The effect of fiber loss, amplification, and sliding-frequency filters on the evolution of optical pulses in nonlinear optical fibers is considered, this evolution being governed by a perturbed nonlinear Schrödinger (NLS) equation. Approximate ordinary differential equations (ODE's) governing the pulse evolution are obtained using conservation and moment equations for the perturbed NLS equation together with a trial function incorporating a solitonlike pulse with independently varying amplitude and width. In addition, the trial function incorporates the interaction between the pulse and the dispersive radiation shed as the pulse evolves. This interaction must be included in order to obtain approximate ODE's whose solutions are in good agreement with full numerical solutions of the governing perturbed NLS equation. The solutions of the approximate ODE's are compared with full numerical solutions of the perturbed NLS equation and very good agreement is found.

Loss of annexin A7 leads to alterations in frequency-induced shortening of isolated murine cardiomyocytes.

Annexin A7 has been proposed to function in the fusion of vesicles, acting as a Ca(2+) channel and as Ca(2+)-activated GTPase, thus inducing Ca(2+)/GTP-dependent secretory events. To understand the function of annexin A7, we have performed targeted disruption of the Anxa7 gene in mice. Matings between heterozygous mice produced offspring showing a normal Mendelian pattern of inheritance, indicating that the loss of annexin A7 did not interfere with viability in utero. Mice lacking annexin A7 showed no obvious phenotype and were fertile. To assay for exocytosis, insulin secretion from isolated islets of Langerhans was examined. Ca(2+)-induced and cyclic AMP-mediated potentiation of insulin secretion was unchanged in the absence of annexin A7, suggesting that it is not directly implicated in vesicle fusion. Ca(2+) regulation studied in isolated cardiomyocytes, showed that while cells from early embryos displayed intact Ca(2+) homeostasis and expressed all of the components required for excitation-contraction coupling, cardiomyocytes from adult Anxa7(-/-) mice exhibited an altered cell shortening-frequency relationship when stimulated with high frequencies. This suggests a function for annexin A7 in electromechanical coupling, probably through Ca(2+) homoeostasis.

Radiative losses due to pulse interactions in birefringent nonlinear optical fibers.

The transient evolution of two-polarization pulses in a birefringent nonlinear optical fiber, governed by coupled nonlinear Schrödinger (NLS) equations, is considered. The evolution is studied using a trial function consisting of coupled solitonlike pulses with varying parameters augmented by a radiative shelf in the Lagrangian formulation of the coupled equations, which yields ordinary differential equations for the pulse parameters. It is shown that including mass and momentum fluxes due to the radiative shelf is a requirement to obtain good agreement with full numerical solutions of the governing equations.

Expression of matrilin-1, -2 and -3 in developing mouse limbs and heart.

The expression of matrilin-1, -2 and -3 was studied in the heart and limb during mouse development. Matrilin-1 is transiently expressed in the heart between days 9.5 and 14.5 p.c. Matrilin-2 expression was detected in the heart from day 10.5 p.c. onwards. In the developing limb bud, both matrilin-1 and -3 were observed first at day 12.5 p.c. Throughout development matrilin-3 expression was strictly limited to cartilage, while matrilin-1 was also found in some other forms of connective tissue. Matrilin-2, albeit present around hypertrophic chondrocytes in the growth plate, was mainly expressed in non-skeletal structures. The complementary, but in part overlapping, expression of matrilins indicates the possibility for both redundant and unique functions among the members of this novel family of extracellular matrix proteins.