Diminished medial prefrontal cortex activation during the recollection of stressful events is an acquired characteristic of PTSD.

BACKGROUND: Previous research has shown relatively diminished medial prefrontal cortex activation and heightened psychophysiological responses during the recollection of personal events in post-traumatic stress disorder (PTSD), but the origin of these abnormalities is unknown. Twin studies provide the opportunity to determine whether such abnormalities reflect familial vulnerabilities, result from trauma exposure, or are acquired characteristics of PTSD. METHODS: In this case-control twin study, 26 male identical twin pairs (12 PTSD; 14 non-PTSD) discordant for PTSD and combat exposure recalled and imagined trauma-unrelated stressful and neutral life events using a standard script-driven imagery paradigm during functional magnetic resonance imaging and concurrent skin conductance measurement. RESULTS: Diminished activation in the medial prefrontal cortex during Stressful v. Neutral script-driven imagery was observed in the individuals with PTSD, relative to other groups. CONCLUSIONS: Diminished medial prefrontal cortex activation during Stressful v. Neutral script-driven imagery may be an acquired characteristic of PTSD. If replicated, this finding could be used prospectively to inform diagnosis and the assessment of treatment response.

Do local enhanced services in primary care improve outcomes? Results from a literature review.

OBJECTIVE: This paper aims to examine the role of local enhanced services (LES) as a financial incentive in improving clinical and process outcomes in primary care with a view to discussing their future in light of the Health and Social Care Act. METHODS: A literature review was conducted to identify LES commissioned in the UK in any disease area and to evaluate common themes relating to their impact on outcomes. The literature review consisted of two stages: an initial reference database search (MEDLINE, MEDLINE IN-PROCESS and EMBASE) and a more general internet search. The internet search used free text augmented by a targeted search of key health organisations' websites. Data were extracted from the LES to provide information on the background and context of the LES before going on to describe the incentive structure, health and economic outcomes and limitations of the LES. RESULTS: Although a number of LES were identified in the online search, only 14 reported any data on outcomes. These LES programmes related to 10 different disease areas, with cancer, alcohol dependence and chronic obstructive pulmonary disease (COPD) being the most common health needs. Three common factors between the selected LES emerged that appear to influence the extent of the impact on local health or economic outcomes: (1) a national framework supporting the LES, (2) existing service provision, and (3) the size of the financial incentives. CONCLUSION: The common themes emerging from the literature review suggest that, following the Health and Social Care Act 2012 and newly established national standards, given sufficient attention to planning service specifications, LES could continue to be important in reducing health inequalities and preparing poorly performing general practices for longer term changes directed at improving outcomes and standards in healthcare.

Flyingfish feeding ecology in the eastern Pacific: prey partitioning within a speciose epipelagic community.

To test the hypothesis that prey partitioning contributes to community stability in flyingfish, the gut contents of 359 flyingfish specimens (representing five genera and eight species within Exocoetidae and Hemiramphidae) were collected at 50 dip-net stations during hour-long night-time fishing in oceanic waters of the eastern tropical Pacific Ocean between August and November 2007. Analyses using multidimensional scaling, and analysis of similarity revealed significant dietary differences among species, and similarity percentages tests helped identify the specific prey taxa responsible for these differences. Six species specialized on copepods (58·3-96·9% by number), but targeted different families. Specifically, the barbel flyingfish Exocoetus monocirrhus (n = 205) focused on euchaetids (51·6%), the banded flyingfish Hirundichthys marginatus (n = 24) fed on pontellids (21·8%), while the tropical two-wing flyingfish Exocoetus volitans (n = 11) and the bigwing halfbeak Oxyporhamphus micropterus (n = 34) ingested calanoids (54·6 and 17·0%). In contrast, the whitetip flyingfish Cheilopogon xenopterus (n = 73) and the mirrorwing flyingfish Hirundichthys speculiger (n = 4) had generalized diets comprising similar proportions of amphipod, copepod, mollusc and larval fish prey. Distinct differences in mean fullness, highly digested material, per cent empty guts and mean numbers of prey per gut were also synthesized, and uncovered a pattern of asynchronous feeding. Altogether, these findings provide valuable descriptive data on the diets of an understudied group of epipelagic teleosts, and, by extension, suggest that prey partitioning (taxa and feeding times) may influence flyingfish feeding ecology by reducing interspecific competition.

Cost-effectiveness of childhood influenza vaccination in England and Wales: Results from a dynamic transmission model.

This study uses a dynamic influenza transmission model to directly compare the cost-effectiveness of various policies of annual paediatric influenza vaccination in England and Wales, varying the target age range and level of coverage. The model accounts for both the protection of those immunised and the indirect protection of the rest of the population via herd immunity. The impact of augmenting current practice with a policy to vaccinate pre-school age children, on their own or with school age children, was assessed in terms of quality adjusted life years and health service costs. Vaccinating 2-18 year olds was estimated to be the most cost-effective policy in an incremental cost-effectiveness analysis, at an assumed annual vaccine uptake rate of 50%. The mean incremental cost-effectiveness ratios for this policy was estimated at £251/QALY relative to current practice. Paediatric vaccination would appear to be a highly cost-effective intervention that directly protects those targeted for vaccination, with indirect protection extending to both the very young and the elderly.

Short and long term changes in carbon, nitrogen and acidity in the forest soils under oak at the Alice Holt Environmental Change Network site.

The dynamics of soil properties within a 70 year old oak plot were assessed every five years (1994-2009), by depth and by horizon to identify short term changes in soil carbon and nitrogen stocks, and acidity. The findings were set within a study of long term changes in soil properties in a 180 year chronosequence of oak plots from the same forest. Carbon stock increased significantly in the top mineral horizon - overall increase was 5 t C ha(-1), at a mean accumulation rate of 0.34 t C ha(-1)y(-1), which was mainly due to increase in horizon thickness. No increase was seen when soils were sampled by depth. Differences obtained by depth or horizon sampling due to changes in horizon thickness over time highlight the importance of horizon in the correct evaluation of soil property change in small scale sampling programs. This is particularly important in forest soils with high litter accumulation and low turnover rates when compared to other land uses. Nitrogen stock increases below 10cm soil depth were attributed to insect activity, litterfall variation and a change in water table. Findings were confirmed in the chronosequence study of oak across the forests; increases in soil C stocks of 0.1-0.2 t C ha(-1)y(-1) were calculated across young (~25 years), mid-rotation (~60 years) and old (120+ years) stands. Soil nitrogen increased significantly with canopy age whilst pH increased significantly between young-mid rotation stands but decreased between mid rotation and old stands. Significant increases in pH were also recorded before 2004 in the ECN 70 year old oak plots reflecting overall pollution recovery.

Unusually high predation on chacma baboons (Papio ursinus) by female leopards (Panthera pardus) in the Waterberg Mountains, South Africa.

Leopards do not preferentially favour baboons as prey, but they are considered the primary predators of baboons across Africa. Even in areas where baboons are abundant, their contribution to leopard diet seldom exceeds 5% of biomass. It is suggested that the extreme aggressiveness of baboons, group vigilance and their high mobility when escaping may limit leopard predation. Male baboons are particularly aggressive, and retaliation often leads to the death of the leopard. However, evidence suggests that leopards may learn to catch and kill certain dangerous prey. This study reports predation on chacma baboons by 3 female leopards on a private game reserve in the Waterberg Mountains of South Africa. Potential leopard feeding sites were identified using global positioning system (GPS) location clusters obtained from GPS collars. Over a 5-month period, we investigated 200 potential leopard feeding sites and located 96 leopard feeding/kill sites. Baboons constituted 18.7% of the leopards' biomass intake. The majority of baboons preyed upon were adults and 70% of the kills were diurnal. In terms of the measured variables, there were no significant differences in the way the leopards preyed upon baboons, compared to the rest of the prey species.

Estimating the clinical impact of introducing paediatric influenza vaccination in England and Wales.

Influenza causes a significant burden of disease each year in England and Wales, with the young and the elderly suffering the greatest burden. Children are recognised as playing an important role in the dissemination of the influenza virus. This study examines the population impact of implementing a programme of paediatric vaccination. A dynamic transmission model was used to simulate the impact of vaccination programmes with varying levels of coverage across pre-school and school age children. These analyses suggest that vaccinating as few as 50% of 2-18 year olds could result in a substantial reduction in the annual incidence of influenza related morbidity and mortality across the population. Herd immunity may extend this protection to the young and the elderly. It is assumed that such programmes would be implemented in concert with the current strategy of vaccinating the elderly and younger at risk groups with an inactivated vaccine. In England and Wales, paediatric vaccination of two to eighteen year olds reduced the estimated number of general practice consultations, hospitalisations and deaths arising from influenza A and B infections by up to 95%. This translates into an annual average reduction of approximately 52,000, 1500 and 1200 events, respectively. A policy of paediatric vaccination could significantly reduce the clinical burden of influenza in England and Wales, in all age groups, with the added value of herd immunity helping to protect the young and the elderly who are at highest risk of complications.

Antarctic killer whales make rapid, round-trip movements to subtropical waters: evidence for physiological maintenance migrations?

Killer whales (Orcinus orca) are important predators in high latitudes, where their ecological impact is mediated through their movements. We used satellite telemetry to provide the first evidence of migration for killer whales, characterized by fast (more than 12 km h(-1), 6.5 knots) and direct movements away from Antarctic waters by six of 12 type B killer whales tagged when foraging near the Antarctic Peninsula, including all tags transmitting for more than three weeks. Tags on five of these whales revealed consistent movements to subtropical waters (30-37° S) off Uruguay and Brazil, in surface water temperatures ranging from -1.9°C to 24.2°C; one 109 day track documented a non-stop round trip of almost 9400 km (5075 nmi) in just 42 days. Although whales travelled slower in the warmest waters, there was no obvious interruption in swim speed or direction to indicate calving or prolonged feeding. Furthermore, these movements were aseasonal, initiating over 80 days between February and April; one whale returned to within 40 km of the tagging site at the onset of the austral winter in June. We suggest that these movements may represent periodic maintenance migrations, with warmer waters allowing skin regeneration without the high cost of heat loss: a physiological constraint that may also affect other whales.

Decreased regional cerebral blood flow in medial prefrontal cortex during trauma-unrelated stressful imagery in Vietnam veterans with post-traumatic stress disorder.

BACKGROUND: Neuroimaging research has demonstrated medial prefrontal cortex (mPFC) hyporesponsivity and amygdala hyperresponsivity to trauma-related or emotional stimuli in post-traumatic stress disorder (PTSD). Relatively few studies have examined brain responses to the recollection of stressful, but trauma-unrelated, personal events in PTSD. In the current study, we sought to determine whether regional cerebral blood flow (rCBF) abnormalities in mPFC and amygdala in PTSD could be observed during the recollection of trauma-unrelated stressful personal events. METHOD: Participants were 35 right-handed male combat veterans (MCVs) and female nurse veterans (FNVs) who served in Vietnam: 17 (seven male, 10 female) with current military-related PTSD and 18 (nine male, nine female) with no current or lifetime PTSD. We used positron emission tomography (PET) and script-driven imagery to study rCBF during the recollection of trauma-unrelated stressful versus neutral and traumatic events. RESULTS: Voxelwise tests revealed significant between-group differences for the trauma-unrelated stressful versus neutral comparison in mPFC, specifically in the anterior cingulate cortex (ACC). Functional region of interest (ROI) analyses demonstrated that this interaction in mPFC represented greater rCBF decreases in the PTSD group during trauma-unrelated stressful imagery relative to neutral imagery compared to the non-PTSD group. No differential amygdala activation was observed between groups or in either group separately. CONCLUSIONS: Veterans with PTSD, compared to those without PTSD, exhibited decreased rCBF in mPFC during mental imagery of trauma-unrelated stressful personal experiences. Functional neuroanatomical models of PTSD must account for diminished mPFC responses that extend to emotional stimuli, including stressful personal experiences that are not directly related to PTSD.

The effects of phytophagous insects on water and soil nutrient concentrations and fluxes through forest stands of the Level II monitoring network in the UK.

The effects of insect defoliators on throughfall and soil nutrient fluxes were studied in coniferous and deciduous stands at five UK intensive monitoring plots (1998 to 2008). Links were found between the dissolved organic carbon (DOC), nitrogen (N) and potassium (K) fluxes through the forest system to biological activity within the canopy. Underlying soil type determined the leaching or accumulation of these elements. Under oak, monitored at two sites, frass from caterpillars of Tortrix viridana and Operophtera brumata added direct deposition of ~16kgha(-1)extra N during defoliation. Peaks of nitrate (NO(3)-N) flux between 5 and 9kgha(-1) (×5 usual winter values) were recorded in consecutive years in shallow soil waters. Synchronous rises in deep soil NO(3)-N fluxes at the Grizedale sandy site indicate downward flushing, not seen at the clay site. Under three Sitka spruce stands, generation of honeydew (DOC) was attributed to two aphid species (Elatobium abietinum and Cinara pilicornis) with distinctive feeding strategies. Throughfall DOC showed mean annual fluxes (6 seasons) ~45-60kgha(-1) compared with rainfall values of 14-22kgha(-1). Increases of total N in throughfall and NO(3)-N fluxes in shallow soil solution were detected - soil water fluxes reached 8kgha(-1) in Llyn Brianne, ~25kgha(-1) in Tummel, and ~40kg NO(3)-Nha(-1) in Coalburn. At Tummel, on sandy soil, NO(3)-N leaching showed increased concentration at depth, attributed to microbiological activity within the soil. By contrast, at Coalburn and Llyn Brianne, sites on peaty gleys, soil water NO(3)-N was retained mostly within the humus layer. Soil type is thus key to predicting N movement and retention patterns. These long term analyses show important direct and indirect effects of phytophagous insects in forest ecosystems, on above and below ground processes affecting tree growth, soil condition, vegetation and water quality.

The influence of gonadal hormones on conditioned fear extinction in healthy humans.

Recent rodent studies suggest that gonadal hormones influence extinction of conditioned fear. Here we investigated sex differences in, and the influence of estradiol and progesterone on, fear extinction in healthy humans. Men and women underwent a two-day paradigm in which fear conditioning and extinction learning took place on day 1 and extinction recall was tested on day 2. Visual cues were used as the conditioned stimuli and a mild electric shock was used as the unconditioned stimulus. Skin conductance was recorded throughout the experiment and used to measure conditioned responses (CRs). Blood samples were obtained from all women to measure estradiol and progesterone levels. We found that higher estradiol during extinction learning enhanced subsequent extinction recall but had no effects on fear acquisition or extinction learning itself. Sex differences were only observed during acquisition, with men exhibiting significantly higher CRs. After dividing women into low- and high-estradiol groups, men showed comparable extinction recall to high-estradiol women, and both of these groups showed higher extinction recall than low-estradiol women. Therefore, sex differences in extinction memory emerged only after taking into account women's estradiol levels. Lower estradiol may impair extinction consolidation in women. These findings could have practical applications in the treatment of anxiety disorders through cognitive and behavioral therapies.

Chemical fluxes in time through forest ecosystems in the UK - soil response to pollution recovery.

Long term trend analysis of bulk precipitation, throughfall and soil solution elemental fluxes from 12 years monitoring at 10 ICP Level II forest sites in the UK reveal coherent national chemical trends indicating recovery from sulphur deposition and acidification. Soil solution pH increased and sulphate and aluminium decreased at most sites. Trends in nitrogen were variable and dependant on its form. Dissolved organic nitrogen increased in bulk precipitation, throughfall and soil solution at most sites. Nitrate in soil solution declined at sites receiving high nitrogen deposition. Increase in soil dissolved organic carbon was detected - a response to pollution recovery, changes in soil temperature and/or increased microbial activity. An increase of sodium and chloride was evident - a possible result of more frequent storm events at exposed sites. The intensive and integrated nature of monitoring enables the relationships between climate/pollutant exposure and chemical/biological response in forestry to be explored.

Molecular epidemiology of tuberculosis in England, 1998.

SETTING: England. OBJECTIVE: To investigate the proportion of tuberculosis (TB) cases attributable to recent transmission and factors associated with clustering. DESIGN: Demographic, clinical and microbiological surveillance data were collated from all new culture-confirmed cases in 1998. Using insertion sequence (IS) 6110 restriction fragment length polymorphism (RFLP) typing, strains were classified as clustered (identical patterns) or unique and risk factors were determined using multivariable logistic regression. RESULTS: RFLP patterns were available for 2265 of 3713 (61%) cases: 1808 had >or=5 IS6110 copies, while 372 cases were in 152 clusters, giving an estimated proportion due to recent transmission of 12.2%.Pulmonary disease (aOR 1.6; 95%CI 1.1-2.2), previous treatment (aOR 3.7; 2.2-6.5) and homelessness (aOR 5.5; 1.2-24.1) were independent risk factors for clustering. Fourteen per cent of patients of Indian subcontinent origin were clustered compared with 27% of white patients. Many clusters spanned ethnic groups (45%) and geographical regions (47%). CONCLUSION: The calculated proportion of TB cases due to recent transmission is low.Adjusting for missed cases and study duration, it increases to 27.6%. Many cases may arise from reactivation or acquisition outside England. Transmission within England accounted for approximately one in four cases and occurred over wide geographic areas, between ethnic groups and among the homeless. Molecular epidemiology can inform local and national public health action.

Childhood peak flow and the Oxford Transport Strategy.

BACKGROUND: Studies of the health effects of traffic interventions are rare. The Oxford Transport Strategy (OTS), implemented in June 1999, involved a wide range of permanent changes designed to reduce congestion in the city centre of Oxford, UK. The impact of the OTS on peak expiratory flow (PEF) and respiratory symptoms among schoolchildren in the city is reported. METHODS: A dynamic cohort of 1389 children aged 6-10 years attending first schools in Oxford was studied. Schools were visited 2-3 times a year for 5-day periods between 1998 and 2000. On each day of each visit children had their PEF measured and were asked about their respiratory symptoms. RESULTS: Changes in traffic varied across the city. In the whole population, regression analysis of daily PEF adjusting for potential confounders showed statistically significant improvements post-OTS (beta = 5.52 l/min, 95% CI 3.08 to 7.97), but there was no consistent evidence that these improvements varied by changes in traffic exposure. In post-hoc analyses, children currently receiving treatment for asthma tended to experience a greater increase in PEF post-OTS as did children from less affluent homes, although these differences did not reach statistical significance. In each of these groups, greater benefits were observed among those living near roads where traffic levels fell post-OTS. CONCLUSIONS: These findings suggest that traffic management may lead to small localised improvements in childhood respiratory health and that such benefits are limited to children with pre-existing respiratory problems and those from less affluent backgrounds.

Assessing the burden of influenza and other respiratory infections in England and Wales.

OBJECTIVES: To estimate the burden of influenza in England and Wales, in terms of general practice consultations, hospital admissions and deaths. METHODS: Multivariable regression was used to estimate the influenza attributable fraction of general practice consultations recorded in the general practice research database, of hospital admissions from hospital episode statistics and of deaths recorded by the Office of National Statistics. RESULTS: An estimated 779,000 (95%CI+/-258,000)-1,164,000 (95%CI+/-425,000) general practice consultations, 19,000 (95%CI+/-5000)-31,200 (95%CI+/-11,000) hospital admissions and 18,500 (95%CI 2500)-24,800 (95%CI+/-2500) deaths annually are attributable to influenza infections. In primary care, the bulk of the burden falls on those under the age of 45, whereas the elderly are more likely to be hospitalised and to die. CONCLUSIONS: Although there are significant uncertainties, and considerable year on year variations, it is clear that the burden of influenza is considerable. Although much of this burden falls on the elderly, significant numbers of general practice consultations, hospitalisations and even some deaths occur annually in children in England and Wales.

Tuberculosis screening in migrants in selected European countries shows wide disparities.

Well-established tuberculosis screening units in Western Europe were selectively sampled. Three screening units in Norway, two in the UK, one in the Netherlands and one in Switzerland were evaluated. The aim of this study was to describe a range of service models used at a number of individual tuberculosis units for the screening of new entrants into Europe. Semi-structured interviews were conducted with clinicians, nurses and administrators from a selected sample of European tuberculosis screening units. An outline of key themes to be addressed was forwarded to units ahead of scheduled interviews. Themes included the history of the unit, structure, processes and outputs involved in screening new entrants for tuberculosis. Considerable variation in screening services exists in the approaches studied. Units are sited in transit camps or as units within hospital facilities. Staff capacity and administration varies from one clinic per week with few dedicated staff to fully dedicated units. Only one site recorded symptoms; tuberculin testing was universal in children, but varied in adults; chest radiograph screening was universal except at one site where a positive tuberculin skin test or symptoms were required in those <35 yrs of age before ordering a radiograph. Few output data are routinely and systematically collected, which hinders comparison and determination of effectiveness and efficiency. Service models for screening new immigrants for tuberculosis appear to vary in Western Europe. The systematic collection of data would make international comparisons between units easier and help draw conclusions that might usefully inform service development.