Ghrelin decreases sensitivity to negative feedback and increases prediction-error related caudate activity in humans, a randomized controlled trial

The stomach-derived hormone ghrelin plays not only a role in feeding, starvation, and survival, but it has been suggested to also be involved in the stress response, in neuropsychiatric conditions, and in alcohol and drug use disorders. Mechanisms related to reward processing might mediate ghrelin's broader effects on complex behaviors, as indicated by animal studies and mostly correlative human studies. Here, using a within-subject double-blind placebo-controlled design with intravenous ghrelin infusion in healthy volunteers (n = 30), we tested whether ghrelin alters sensitivity to reward and punishment in a reward learning task. Parameters were derived from a computational model of participants' task behavior. The reversal learning task with monetary rewards was performed during functional brain imaging to investigate ghrelin effects on brain signals related to reward prediction errors. Compared to placebo, ghrelin decreased punishment sensitivity (t = -2.448, p = 0.021), while reward sensitivity was unaltered (t = 0.8, p = 0.43). We furthermore found increased prediction-error related activity in the dorsal striatum during ghrelin administration (region of interest analysis: t-values ≥ 4.21, p-values ≤ 0.044). Our results support a role for ghrelin in reward processing that extends beyond food-related rewards. Reduced sensitivity to negative outcomes and increased processing of prediction errors may be beneficial for food foraging when hungry but could also relate to increased risk taking and impulsivity in the broader context of addictive behaviors.

Intertemporal prosocial behavior: a review and research agenda

Research on intertemporal and prosocial decisions has largely developed in separate strands of literature. However, many of the decisions we make occur at the intersection of these two dimensions (intertemporal and prosocial). Trust is an example, where a decision today is made with the expectation that another person will reciprocate (or betray) later. A new literature is emerging to explore the role of time in these types of situations, where time and social considerations are intertwined. In many cases, time introduces (or magnifies) an element of uncertainty about future outcomes and utility that people need to deal with - what will happen, how good will it be, how will it feel. We review this emerging literature on intertemporal prosocial decision-making and discuss how new research can fill existing knowledge gaps.

The effect of fast and slow decision-making on equity-efficiency tradeoffs and moral repugnance

Fast-and-slow models of decision-making are commonly invoked to explain economic behaviour. However, past research has focused on human cooperation and generosity and thus largely overlooked situations where there are sharp conflicts between efficiency and equality, or between efficiency and more intuitive moral values (repugnance). Here, we contribute to fill this gap in the literature. We conducted a preregistered experiment (n = 1500 recruited from Prolific) to assess the effects of fast, intuitive decisions, under time pressure versus slow, deliberate decisions, under time delay, on (i) people's distributional preferences and (ii) their attitudes toward repugnant transactions. The results show increased preference for equality and decreased preference for efficiency under time pressure, but no effects on moral repugnance. Exploratory analyses revealed that most of the observed treatment effects in our data were accounted for by women. Our results provide some support for theories that associate controlled cognition with concern for efficiency, and intuitive, emotional responses with inequality aversion.

A randomized controlled experimental medicine study of ghrelin in value-based decision making

BACKGROUND

The stomach-derived hormone ghrelin stimulates appetite, but the ghrelin receptor is also expressed in brain circuits involved in motivation and reward. We examined ghrelin effects on decision making beyond food or drug rewards, using monetary outcomes.

METHODS

Thirty participants (50% females) underwent two fMRI scans, in randomized counterbalanced order, while receiving intravenous ghrelin or saline.

RESULTS

Striatal representations of reward anticipation were unaffected by ghrelin, while activity during anticipation of losses was attenuated. Temporal discounting rates of monetary rewards were lower overall in the ghrelin condition, an effect driven by women. Discounting rates were inversely correlated with neural activity in a large cluster within the left parietal lobule that included the angular gyrus. Activity in an overlapping cluster was related to behavioral choices, and was suppressed by ghrelin.

CONCLUSION

This is to our knowledge the first human study to extend the understanding of ghrelin's significance beyond the canonical feeding domain or in relation to addictive substances. Contrary to our hypothesis, we find that ghrelin does not affect sensitivity to monetary reward anticipation, but rather results in attenuated loss aversion and lower discounting rates for these rewards. Ghrelin may cause a motivational shift toward caloric rewards rather than globally promoting the value of rewards.

TRIAL REGISTRATION

EudraCT 2018-004829-82FUNDING. Swedish Research Council (MH: 2013-07434) and Marcus and Marianne Wallenberg foundation (GT: 2014.0187). Author LL is supported by NIDA/NIAAA IRP.

Voting and (im)moral behavior

Due to diffusion of responsibility, majority voting may induce immoral and selfish behavior because voters are rarely solely responsible for the outcome. Across three behavioral experiments (two preregistered; n = 1983), we test this hypothesis in situations where there is a conflict between morality and material self-interest. Participants were randomly assigned to make decisions about extracting money from a charity either in an experimental referendum or individually. We find no evidence that voting induces immoral behavior. Neither do we find that people self-servingly distort their beliefs about their responsibility for the outcome when they vote. If anything, the results suggest that voting makes people less immoral.

COVID-19 and Politically Motivated Reasoning

Background

During the COVID-19 pandemic, the world witnessed a partisan segregation of beliefs toward the global health crisis and its management. Politically motivated reasoning, the tendency to interpret information in accordance with individual motives to protect valued beliefs rather than objectively considering the facts, could represent a key process involved in the polarization of attitudes. The objective of this study was to explore politically motivated reasoning when participants assess information regarding COVID-19.

Design

We carried out a preregistered online experiment using a diverse sample (N = 1,500) from the United States. Both Republicans and Democrats assessed the same COVID-19–related information about the health effects of lockdowns, social distancing, vaccination, hydroxychloroquine, and wearing face masks.

Results

At odds with our prestated hypothesis, we found no evidence in line with politically motivated reasoning when interpreting numerical information about COVID-19. Moreover, we found no evidence supporting the idea that numeric ability or cognitive sophistication bolster politically motivated reasoning in the case of COVID-19. Instead, our findings suggest that participants base their assessment on prior beliefs of the matter.

Conclusions

Our findings suggest that politically polarized attitudes toward COVID-19 are more likely to be driven by lack of reasoning than politically motivated reasoning—a finding that opens potential avenues for combating political polarization about important health care topics.

Highlights

Acute effects of alcohol on social and personal decision making

Social drinking is common, but it is unclear how moderate levels of alcohol influence decision making. Most prior studies have focused on adverse long-term effects on cognitive and executive function in people with alcohol use disorders (AUD). Some studies have investigated the acute effects of alcohol on decision making in healthy people, but have predominantly used small samples and focused on a narrow selection of tasks related to personal decision making, e.g., delay or probability discounting. Here, we conducted a large (n = 264), preregistered randomized placebo-controlled study (RCT) using a parallel group design, to systematically assess the acute effects of alcohol on measures of decision making in both personal and social domains. We found a robust effect of a 0.6 g/kg dose of alcohol on both moral judgment and altruistic behavior, but no effects on several measures of risk taking or waiting impulsivity. These findings suggest that alcohol at low to moderate doses selectively moderates decision making in the social domain, and promotes utilitarian decisions over those dictated by rule-based ethical principles (deontological). This is consistent with existing theory that emphasizes the dual roles of shortsighted information processing and salient social cues in shaping decisions made under the influence of alcohol. A better understanding of these effects is important to understand altered social functioning during alcohol intoxication.

Differences in Physical Demands Among Offensive and Defensive Players in Elite Men Bandy

Purpose: This study examined the physiological sport-specific demands (total distance, mean velocity, effective game time, and time in five velocity zones) in elite bandy players of offensive and defensive playing positions. Method: Data were collected with 10 Hz GPS-units in the Swedish Elite League during the season 2015/16. Ten male elite bandy players were examined during 13 matches. Data were analyzed with Independent Samples Test and with descriptive statistics. Result: Analysis showed that defensive positions covered a significantly longer (p < .001) total distance (23.2 ± 2.4 km vs 21.1 ± 3.5 km) compared to the offensive positions. Significantly higher (p < .001) mean velocity was found in offensive positions (17.8 ± 1.0 km/h vs 15.5 ± 1.6 km/h) in relation to defensive positions. In variable effective game time analysis exposed significant differences (p < .001) between offensive positions and defensive positions (90.4 ± 3.5 min vs 71.3 ± 11.9 min). Furthermore, in easy and moderate skating defensive positions spent significantly (p < .001) more time and in fast, very fast, and sprint skating offensive positions spent significantly (p < .001) more time in relation to each other. The descriptive analysis of positions indicates that libero, defender, and half have the longest game time, half skate the longest distance, and forward have the highest mean velocity during the game. Conclusion: From a practical perspective, the result can provide coaches knowledge when planning the setup in training drills. Thus, the training sessions could be more specific to the playing position, which could maximize the player's physiological outcome in order to optimize performance.

Coronary collaterals provide more than half of normal perfusion in patients with coronary artery disease - quantification by myocardial perfusion SPECT during elective balloon occlusion

Funding Acknowledgements

Type of funding sources: None.

BACKGROUND

The coronary collateral circulation is a preformed network of anastomotic connections acting as a "natural bypass" mechanism. Whilst the prevalence of collaterals varies between species, approximately 25% of patients have angiographically visible robust collaterals at the time of ST elevation myocardial infarction. While the presence of collaterals is associated with improved outcomes, the magnitude of myocardial perfusion which can be provided by the collateral circulation remains uncertain.

PURPOSE

The aim was to quantify collateral myocardial perfusion during experimental coronary balloon occlusion in patients with CAD.

METHODS

The study was approved by the local investigational review board, and all patients provided informed consent. Patients without prior infarction, bypass surgery, or angiographically visible collaterals undergoing elective percutaneous transluminal coronary angioplasty (PTCA) to a single epicardial vessel, underwent two scans with 99mTc-sestamibi myocardial perfusion single-photon emission computed tomography (SPECT). All subjects underwent at least three minutes of angiographically verified complete balloon occlusion, at which time an intravenous injection of the radiotracer was administered, followed by SPECT imaging. A second radiotracer injection followed by SPECT imaging was performed 24 hours after PTCA.

RESULTS

The study included 21 patients (median [interquartile range] age 70 [56-74] years, 52% male). The degree of diameter stenosis of treated vessels ranged from 60-99%, with successful PTCA performed with a mean 5-minute balloon occlusion time, resulting in ≤20% residual stenosis in all cases. The vessels undergoing PTCA were 6 in the LAD, 5 in the LCx, and 10 in the RCA. For the cohort, the size of the perfusion defect was 16 [8-30]% of the LV and the collateral perfusion at rest within the perfusion defect was 64 [58-68]% of normal perfusion within that region. Collateral perfusion was negatively correlated with perfusion defect size (R2 = 0.85, p &lt; 0.001), but did not differ by sex (p = 0.27) or age (p = 0.58). CONCLUSIONS: This is the first study to describe the magnitude of microvascular collateral perfusion in CAD. On average, despite coronary occlusion and an absence of angiographically visible collateral vessels, collaterals provide approximately 60% of the perfusion that reaches the jeopardized myocardium during coronary occlusion. This magnitude of collateral perfusion is much higher than previously speculated. A previous study using microspheres in dogs found that collateral perfusion in the setting of an occluded vessel was 6% of normal. By comparison, the current study found ten times greater collateral perfusion in patients with CAD.

Abstract Figure. Collateral perfusion during occlusion.

Using quantitative trait in adults with ADHD to test predictions of dual-process theory

Dual-process theory is a widely utilized modelling tool in the behavioral sciences. It conceptualizes decision-making as an interaction between two types of cognitive processes, some of them fast and intuitive, others slow and reflective. We make a novel contribution to this literature by exploring differences between adults with clinically diagnosed ADHD and healthy controls for a wide range of behaviors. Given the clinical picture and nature of ADHD symptoms, we had a strong a priori reason to expect differences in intuitive vs reflective processing; and thus an unusually strong case for testing the predictions of dual-process theory. We found mixed results, with overall weaker effects than expected, except for risk taking, where individuals with ADHD showed increased domain sensitivity for gains vs losses. Some of our predictions were supported by the data but other patterns are more difficult to reconcile with theory. On balance, our results provide only limited empirical support for using dual-process theory to understand basic social and economic decision-making.

Variation in the μ-Opioid Receptor Gene (OPRM1) Does Not Moderate Social-Rejection Sensitivity in Humans

Given previous findings from animal studies and small-scale studies in humans, variation in the μ-opioid receptor gene ( OPRM1) has been proposed as a strong biological candidate for moderating sensitivity to social rejection. Using a substantially larger sample ( N = 490) than previous studies, a prospective genotyping strategy, and preregistered analysis plans, we tested the hypotheses that OPRM1 variation measured by the functional A118G polymorphism (rs1799971) moderates (a) dispositional sensitivity to rejection and feelings of distress following social exclusion and (b) decision making involving social cognition. In three experimental tasks commonly used to assess altruism, reciprocity, and trust in humans, we found no evidence in favor of the hypotheses; nine main tests were preregistered, and all of them yielded small and statistically insignificant estimates. In secondary analyses, we used Bayesian inference and estimation to quantify support for our findings. Taken together, our results strongly suggest that the link between OPRM1 A118G variation and social-rejection sensitivity is weaker than previously thought.

Abstract P5-07-08: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Persson E, Gregersson P, Fitzpatrick P, Ståhlberg A, Landberg G. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-07-08.

Discrepancy between Health Care Rationing at the Bedside and Policy Level

BACKGROUND

Whether doctors at the bedside level should be engaged in health care rationing is a controversial topic that has spurred much debate. From an empirical point of view, a key issue is whether there exists a behavioral difference between rationing at the bedside and policy level. Psychological theory suggests that we should indeed expect such a difference, but existing empirical evidence is inconclusive.

OBJECTIVE

To explore whether rationing decisions taken at the bedside level are different from rationing decisions taken at the policy level.

METHOD

Behavioral experiment where participants ( n = 573) made rationing decisions in hypothetical scenarios. Participants (medical and nonmedical students) were randomly assigned to either a bedside or a policy condition. Each scenario involved 1 decision, concerning either a life-saving medical treatment or a quality-of-life improving treatment. All scenarios were identical across the bedside and policy condition except for the level of decision making.

RESULTS

We found a discrepancy between health care rationing at policy and bedside level for scenarios involving life-saving decisions, where subjects rationed treatments to a greater extent at the policy level compared to bedside level (35.6% v. 29.3%, P = 0.001). Medical students were more likely to ration care compared to nonmedical students. Follow-up questions showed that bedside rationing was more emotionally burdensome than rationing at the policy level, indicating that psychological factors likely play a key role in explaining the observed behavioral differences. We found no difference in rationing between bedside and policy level for quality-of-life improving treatments (54.6% v. 55.7%, P = 0.507).

CONCLUSIONS

Our results indicate a robust "bedside effect" in the life-saving domain of health care rationing decisions, thereby adding new insights to the understanding of the malleability of preferences related to resource allocation.

Low degree of satisfactory individual pain relief in post-operative pain trials

BACKGROUND

The majority of clinical trials regarding post-operative pain treatment focuses on the average analgesic efficacy, rather than on efficacy in individual patients. It has been argued, that in acute pain trials, the underlying distributions are often skewed, which makes the average unfit as the only way to measure efficacy. Consequently, dichotomised, individual responder analyses using a predefined 'favourable' response, e.g. Visual Analogue Scale (VAS) pain scores ≤ 30, have recently been suggested as a more clinical relevant outcome.

METHODS

We re-analysed data from 16 randomised controlled trials of post-operative pain treatment and from meta-analyses of a systematic review regarding hip arthroplasty. The predefined success criterion was that at least 80% of patients in active treatment groups should obtain VAS < 30 at 6 and 24 h post-operatively.

RESULTS

In the analysis of data from the randomised controlled trials, we found that at 6 h post-operatively, 50% (95% CI: 31-69) of patients allocated to active treatment reached the success criterion for pain at rest and 14% (95% CI: 5-34) for pain during mobilisation. At 24 h post-operatively, 60% (95% CI: 38-78) of patients allocated to active treatment reached the success criterion for pain at rest, and 15% (95% CI: 5-36) for pain during mobilisation. Similar results were found for trials from the meta-analyses.

CONCLUSION

Our results indicate that for conventional, explanatory trials of post-operative pain, individual patient's achievement of a favourable response to analgesic treatment is rather low. Future pragmatic clinical trials should focus on both average pain levels and individual responder analyses in order to promote effective pain treatment at the individually patient level.

Dose related effects of LPS on endometrial epithelial cell populations from dioestrus cows

Lipopolysaccharides (LPS) from Gram negative bacteria are involved in the pathogeny of uterine diseases in cows. This study aimed to investigate LPS effects on the growth of bovine endometrial epithelial cells (bEEC) and relationships between LPS response and tissue characteristics. Uteri from 35 females were characterized for parity and stage of oestrous cycle. Densities of glandular tissue (dGT), CD11b+ cells and Ki67+ cells were measured in the endometrial tissue. Cells from 13 dioestrus cows were exposed to 0, 2, 4, 8, 12, 16 or 24μg/mL LPS. Effects of parity and stage of the oestrous cycle on tissue characteristics and effects of LPS dosage, cow and tissue characteristics on changes in cell numbers were analyzed by ANOVA. The dGT was higher in metoestrus and dioestrus samples than in pro-oestrus ones whereas densities of CD11b+ and Ki67+ cells were higher at pro-oestrus (p<0.05-p<0.01). LPS influenced bEEC populations in a dose related manner. An increase in number of live cells was observed for dosages ranging from 2 to 12μg/mL LPS (p<0.0001 vs controls). No effect was found on numbers and frequencies of dead cells. With higher dosages, the numbers of live cells did not increase but the numbers of dead did increase. No relationships were observed between cow or tissue characteristics and growth patterns or frequencies of viable bEEC in controls nor in the response to LPS. To conclude this model is suitable for further studies on dysregulations induced by LPS in endometrial tissue.

Pain rehabilitation with language interpreter, a multicenter development project

Aims

To describe patients with persistent pain participating in multimodal rehabilitation with language interpreter (MMRI) with regard to demographic data, pain, anxiety, depression, fear of movement, health related quality of life before and after rehabilitation.

Methods

The university rehabilitation departments in Lund and Stockholm developed multimodal rehabilitation programmes for patients who cannot participate in ordinary programmes due to insufficient knowledge in Swedish. From 2014 to 2015, 50 patients participated in the MMRI. Data was collected at admission and discharge with instruments from the Swedish quality registry for pain rehabilitation. The assessments included health related quality of life (EQ5D), anxiety and depression (HADS), fear of movements (TSK), disability (PDI).

Preliminary results

Fifty patients participated in MMRI. Seventy-eight percent were women, and 88% were born outside Europe. Compared to patients participating in Swedish regular rehabilitation programmes (MMR), the level of education was low, 44% had finished high school (55% in MMR in Sweden) and 8% university (27% in MMR in Sweden). Also the distribution of pain differed; in MMRI 40% reported pain with varying localization compared to 33% in MMR. Both groups were frequent health care seekers, even though MMRl’s patients reported a higher frequency of visits than MMR regular patients; 94% of MMRl’s patients compared to 70% MMR patients were seeking physicians more than 4 times due to pain during the previous year. Both groups report very low health related quality of life. In the MMRI group, at admission, the EQ5Dindex was 0.088 (md) (MMR 0.157). This can be compared with 0.83, the value for the Swedish norm population.

Conclusions

Patients participating in MMRI, compared to patients participating in MMR, reported poorer health, higher rate of visit to physicians due to pain and less higher education than other, Swedish speaking pain patients attending to the country pain programmes.

Overestimation of N-glycoPEGylated factor IX activity in a one-stage factor IX clotting assay owing to silica-mediated premature conversion to activated factor IX

Essentials Nonacog beta pegol (N9-GP) activity is overestimated in clot method using silica-based reagents. Mimicking contact activation phase with silica reveals N9-GP activation before recalcification. Localization of N9-GP to silica facilitates activation by factor XIa and plasma kallikrein. Silica-based reagents to be used with caution when monitoring N9-GP therapy using clot method.

SUMMARY

Background Clinical laboratories routinely quantify factor IX (FIX) activity by measurement of the activated partial thromboplastin time (APTT) in a one-stage (OS) clotting assay. This assay can be performed with any of a plethora of differently composed APTT reagents, giving variable recovery when applied to nonacog beta pegol (N9-GP), an N-glycoPEGylated recombinant FIX. Objective To identify the cause of observed overestimations of N9-GP activity in an OS FIX clotting assay when most APTT reagents containing silica are used as the contact activator, and to elucidate the underlying mechanism. Methods Experiments mimicking the contact activation and clotting phases of the OS assay, combined with the use of plasmas with various deficiencies, were employed to shed light on the unique behavior of N9-GP. Confirmatory activations of N9-GP with purified enzymes and physical adsorption to silica particles were studied, and the influence of free polyethylene glycol (PEG) on these processes was investigated. Results N9-GP, but not native FIX, added to FIX-deficient plasma was prematurely converted to activated FIX (FIXa) during the contact activation phase of the clotting assay. Activated FXI (FXIa) and plasma kallikrein (PK) were responsible for the activation of N9-GP, an event that appeared to require the presence of a silica-containing APTT reagent. PEG-dependent adsorption of N9-GP to silica particles could be demonstrated. Conclusions The PEG moiety mediates colocalization of N9-GP with its activators FXIa and PK on silica surfaces, thereby facilitating premature conversion of N9-GP to FIXa during the contact activation phase, and leading to overestimation of the FIX activity in the OS clotting assay.

Tissue factor activates allosteric networks in factor VIIa through structural and dynamic changes

BACKGROUND

Tissue factor (TF) promotes colocalization of enzyme (factor VIIa) and substrate (FX or FIX), and stabilizes the active conformation of FVIIa. Details on how TF induces structural and dynamic changes in the catalytic domain of FVIIa to enhance its efficiency remain elusive.

OBJECTIVE

To elucidate the activation of allosteric networks in the catalytic domain of the FVIIa protease it is when bound to TF.

METHODS

Long-timescale molecular dynamics simulations of FVIIa, free and in complex with TF, were executed and analyzed by dynamic network analysis.

RESULTS

Allosteric paths of correlated motion from the TF contact point, Met306, in FVIIa to the active site triad can be described and quantified. In particular, the shortest paths from Met306 to Ser344 and His193 are 16% and 8% longer in free FVIIa than in TF-FVIIa, and they encompass previously undiscovered residue-residue interactions that are not likely to be inferred from mutagenesis studies. Furthermore, paths from Met306 to Ile153 (N-terminus) and Trp364, both representing hallmark residues of allostery, are 7% and 37% longer, respectively, in free FVIIa. Thus, there is significantly weaker coupling between the TF contact point and key residues in the catalytic domain of FVIIa, causing the active site triad to disintegrate in the simulation when TF is not present.

CONCLUSIONS

These findings complement our current understanding of how the protease FVIIa is stimulated by TF. We demonstrate allosteric networks in the catalytic domain that are activated by TF and help to make FVIIa an efficient catalyst of FIX and FX activation.

Tank-connected food waste disposer systems--current status and potential improvements

An unconventional system for separate collection of food waste was investigated through evaluation of three full-scale systems in the city of Malmö, Sweden. Ground food waste is led to a separate settling tank where food waste sludge is collected regularly with a tank-vehicle. These tank-connected systems can be seen as a promising method for separate collection of food waste from both households and restaurants. Ground food waste collected from these systems is rich in fat and has a high methane potential when compared to food waste collected in conventional bag systems. The content of heavy metals is low. The concentrations of N-tot and P-tot in sludge collected from sedimentation tanks were on average 46.2 and 3.9 g/kg TS, equalling an estimated 0.48 and 0.05 kg N-tot and P-tot respectively per year and household connected to the food waste disposer system. Detergents in low concentrations can result in increased degradation rates and biogas production, while higher concentrations can result in temporary inhibition of methane production. Concentrations of COD and fat in effluent from full-scale tanks reached an average of 1068 mg/l and 149 mg/l respectively over the five month long evaluation period. Hydrolysis of the ground material is initiated between sludge collection occasions (30 days). Older food waste sludge increases the degradation rate and the risks of fugitive emissions of methane from tanks between collection occasions. Increased particle size decreases hydrolysis rate and could thus decrease losses of carbon and nutrients in the sewerage system, but further studies in full-scale systems are needed to confirm this.

Attosecond probe of valence-electron wave packets by subcycle sculpted laser fields

We experimentally and theoretically demonstrate a self-referenced wave-function retrieval of a valence-electron wave packet during its creation by strong-field ionization with a sculpted laser field. Key is the control over interferences arising at different time scales. Our work shows that the measurement of subcycle electron wave-packet interference patterns can serve as a tool to retrieve the structure and dynamics of the valence-electron cloud in atoms on a sub-10-as time scale.

Platelet binding and activity of a factor VIIa variant with enhanced tissue factor independent activity

BACKGROUND AND OBJECTIVES

Platelet binding and activity play important roles in the efficacy of factor VIIa (FVIIa) as a bypassing agent for hemophilia treatment. An analog of FVIIa with increased tissue factor (TF)-independent activity, NN1731, has been produced by introducing three amino acid changes in the protease domain. NN1731 has a conformation similar to TF-bound FVIIa, even in the absence of TF. This results in much greater intrinsic proteolytic activity, but similar activity in the presence of TF.

OBJECTIVES

We hypothesized that these changes would not alter binding to platelets or phospholipid, a characteristic thought to be localized to the Gla domain. The goal of the current work was to compare platelet binding and activity of NN1731 and wild-type FVIIa.

METHODS/RESULTS

FVIIa and NN1731 bound identically to phospholipid vesicles as assessed by both activity assays and electrophoretic quasielastic light scattering techniques. However, NN1731 bound to a greater number of sites on activated platelets than FVIIa, as assessed by flow cytometry. Removal of the Gla domain abolished binding of both FVIIa and NN1731. Inhibition of the active site did not reduce NN1731 binding to the level of FVIIa. When corrected for the amount of protein bound, NN1731 had greater activity than FVIIa on platelet surfaces.

CONCLUSIONS

While the Gla domain is essential for FVIIa binding to platelets, changes in the protease domain in NN1731 enhanced platelet binding as well as proteolytic activity. Features in addition to lipid composition appear to contribute to binding of rFVIIa and, especially, NN1731 to platelets.

Stoma-related complications and stoma size - a 2-year follow up

AIM

The purpose of the study was to prospectively describe stoma configuration and evaluate stoma-related complications and their association with possible risk factors.

METHOD

All elective patients (n = 180) operated on with a formation of colostomy, ileostomy or loop-ileostomy between 2003 and 2005 were included in the study. Follow up took place on the ward postoperatively and five times during 2 years after discharge. On these occasions the diameter and height of the stoma were recorded. Complications such as peristomal skin problems, necrosis, leakage caused by a low stoma, stenosis, granuloma formation, prolapse and peristomal hernia formation were evaluated.

RESULTS

Most complications occurred 2 weeks after discharge; 53% of patients with colostomies, 79% with loop-ileostomies and 70% of patients with end-ileostomy had one or more complications. The most common complication was skin problems and it was most common in patients with end-ileostomies (60%) and loop-ileostomies (73%). Postoperatively at ward review, the most common complication was necrosis, which occurred in 20% of patients with a colostomy. Granuloma formation was most frequent in colostomies. Almost all patients with an end-ileostomy and loop-ileostomy with a height lower than 20 mm had leakage and skin problems as had half of the patients with a colostomy height lower than 5 mm.

CONCLUSION

To prevent stoma-related complications, it is important to produce an adequate height of the stoma, with early and regular follow ups and adjustment of the appliance. To work closely in collaboration with the colorectal surgeons is of utmost important to provide feedback and in turn, to improve stoma outcome.

Cytokine expression in the gilt oviduct: effects of seminal plasma, spermatozoa and extender after insemination

Effects of semen components [fresh semen in extender, spermatozoa in extender (Spz), seminal plasma (SP)], or extender alone (Beltsville thawing solution, BTS) on the expression of selected cytokines [interleukin (IL)-1beta, IL-6, IL-10 and transforming growth factor (TGF)-beta1)] as well as the presence of cells positive for CD8 or CD25 were studied in the pig oviduct. In addition, cytokines in SP and oviductal flushings were analyzed. In experiment (Exp) I, groups of gilts were sampled at 5-6h after insemination with SP, Spz, fresh semen in BTS or only BTS (control). In Exp II, gilts were sampled 35-40 h after insemination with SP, Spz, BTS or only catheter insertion (control). Most oviductal flushing samples were positive (> or =detectable limits) for IL-10 and TGF-beta1 but only few for IL-6. The IHC-labelling of IL-6, IL-10 and TGF-beta1 was evident, especially in the epithelial cells of the isthmus and infundibulum as well as in the cells of the regional (mesometrial) lymph node. Cilia of the epithelium were positive for IL-6 (strongest in the infundibulum) and TGF-beta1 (strongest in the isthmus) but negative for IL-10. There were no consistent differences in IHC-labelling of the cytokines in relation to different treatments, except at 35-40 h after insemination (Exp II), when IL-6 was slightly higher in epithelium of the SP group and IL-10 in the infundibular connective tissue was higher in the SP and Spz groups. In the isthmus and infundibulum, there were no differences between animals inseminated with BTS (control) and the semen components for any of the cytokine mRNAs at 5-6h after insemination (Exp I). However, later (35-40 h, Exp II), insemination with SP, Spz and BTS alone appeared to up-regulate TGF-beta1 mRNA expression compared with the control group (without any fluid infused). In all treatment groups, the mRNA level for TGF-beta1 was higher than for IL-1beta, IL-6 and IL-10. Higher mRNA levels of all cytokines were found in the isthmus compared with the infundibulum. Numbers of CD8-positive cells (both in epithelium and connective tissue) appeared higher in the infundibulum compared with the isthmus and were mostly higher shortly (Exp I) after treatment with SP, SPZ and BTS than later (Exp II) in both segments. CD25-positive cells were few and found solely in the sub-epithelial connective tissue. The results indicate that in the porcine oviduct, IL-6, IL-10 and TGF-beta1 are endogenous produced and that TGF-beta1 may have a more important role for immunomodulation than the other cytokines, especially in isthmus. Differences between isthmus and infundibulum in cytokine mRNA expression and in presence of CD8-positive cells indicate different patterns of immune reactivity in the upper and lower parts of the oviduct.

Probing electron correlation via attosecond xuv pulses in the two-photon double ionization of helium

Recent experimental developments of high-intensity, short-pulse extreme ultraviolet light sources are enhancing our ability to study electron-electron correlations. We perform time-dependent calculations to investigate the so-called "sequential" regime (variant Planck's over 2piomega > 54.4 eV) in the two-photon double ionization of helium. We show that attosecond pulses allow us not only to probe but also to induce angular and energy correlations of the emitted electrons. The final momentum distribution reveals regions dominated by the Wannier ridge breakup scenario and by postcollision interaction.

Interobserver and intraobserver agreement in the evaluation of CT perfusion in ischemic stroke

Knowledge of interrater reliability in the evaluation of perfusion computed tomography (CTP) studies is very limited even though the method is widely used in the workup of acute stroke. The aims of this study were to estimate the inter- and intraobserver agreement in the evaluation of CTP data and to evaluate the feasibility of the method. The CTP data of 20 consecutive patients (50% were females) aged 68+/-11 years with different categories of acute ischemic stroke were included in this retrospective analysis. Perfusion studies were evaluated independently by six radiologists on two different occasions. The overall inter- and intraobserver agreement was substantial, showing a capital KA, Cyrillic value of 0.65 (95% confidence interval 0.39-0.91). The time required for the post-processing and interpretation ranged from 37 to 460 seconds. Evaluation of manually post-processed CTP data according to the maximum slope model appears to be reliable. Experience and also a short training period increase the reliability of the method and reduce the time needed for delivery of the results to the treating clinician.

A novel derivative for the assessment of urinary and salivary nitrate using gas chromatography/mass spectrometry

Previous gas chromatography/mass spectrometry (GC/MS) methods for determining nitrate in biological samples involve either hazardous chemicals or produce multiple isomers that can be difficult to quantitate. Modification of these methods, by the nitration of mesitylene instead of benzene and in the presence of trifluoroacetic anhydride rather than sulphuric acid, should enable simple isotopic quantitation for use in tracer studies, for example, in the measurement of nitric oxide production. Desiccated urine and saliva samples, in addition to aqueous labelled and unlabelled nitrate standards, were treated with trifluoroacetic anhydride and mesitylene at 70 degrees C for 1 h, cooled, then sequentially washed with deionised water and aqueous sodium bicarbonate. The solution of nitromesitylene in mesitylene was separated, dried and analysed by GC/MS. The full mass spectra exhibited abundant ions at m/z 165 and 166 corresponding to the unlabelled and labelled molecular species of nitromesitylene, respectively. Selected ion monitoring of these masses for a series of gravimetrically prepared standards indicated good agreement with isotopic enrichments in the range 0.0625-5 mole % excess, and at nitrate concentrations within the physiological range of 0.078-2 mmol/L. Derivatised samples were stable with respect to isotopic enrichments and nitrate concentrations at -20 degrees C for up to 21 days and exhibited excellent repeatability. Nitration of mesitylene proved to be a simple and rapid method for the measurement of isotope ratios in aqueous nitrates by GC/MS, which has applications in tracer studies and in concentration determinations by isotope dilution techniques for nitric oxide production.

Osteotropic effects by the neuropeptides calcitonin gene-related peptide, substance P and vasoactive intestinal peptide

Immunohistochemical phenotypic characterization of skeletal nerve fibers has demonstrated the expression of a restricted number of neuropeptides, including calcitonin gene-related peptide (CGRP), substance P (SP) and vasoactive intestinal peptide (VIP). According to the neuro-osteological hypothesis, such neuropeptides can be released and exert paracrine biological effects on bone cells present close to the nerve endings expressing these signaling molecules. The existence of such interplay is most convincingly shown by the hypothalamic control of bone formation, in the case of leptin stimulation of hypothalamic nuclei mediated by the sympathetic nervous system and inhibitory beta-adrenergic receptors on osteoblasts. In addition to these receptors, osteoblasts and osteoclasts express functional receptors for CGRP, SP and VIP, which can regulate both bone formation and bone resorption. The evidence for these observations is summarized in the present paper.

Quantum path interference in the wavelength dependence of high-harmonic generation

We investigate the dependence of the intensity of radiation due to high-harmonic generation as a function of the wavelength lambda of the fundamental driver field. Superimposed on a smooth power-law dependence observed previously, we find surprisingly strong and rapid fluctuations on a fine lambda scale. We identify the origin of these fluctuations in terms of quantum path interferences with up to five returning orbits significantly contributing.

Characterisation of invasive group B streptococci based on investigation of surface proteins and genes encoding surface proteins

The joint distributions of the six genes bca, bac, epsilon/alp1, alp2, alp3 and rib (encoding alpha-C-protein, beta-C-protein, epsilon/Alp1, Alp2, Alp3, and Rib, respectively) and the proteins alpha-C-protein, beta-C-protein and Rib were investigated in invasive isolates of group B streptococcus (GBS). In total, 297 invasive isolates (123 from neonates, 174 from adults) from south-west Sweden were collected during a 13-year period. Genes were detected using multiplex and specific PCRs, and expression of the surface proteins was demonstrated using monoclonal antibodies. The genes studied were found alone or in combinations in 294 (99%) of the invasive isolates. The most common genes were rib (n = 127 isolates, 43%), alp3 (n = 78, 26%) and epsilon/alp1 (n = 42, 14%). The bac gene was never found alone, but was found in combination with one other gene in 36 isolates. The surface proteins studied were detected alone or in combinations in 152 (51%) isolates, with the most common being Rib (n = 80, 27%), alpha-C-protein (n = 68, 23%) and beta-C-protein (n = 24, 8%). Several genes were associated significantly with particular serotypes (e.g., epsilon/alp1 with serotype Ia; bca and bac with serotypes Ib and II; rib with serotype III; alp3 with serotype V). Overall, it was concluded that demonstration of different genes and surface proteins of GBS strains can be useful in epidemiological studies and in formulation of vaccines, but disappointingly, no single gene or surface protein included in the study was sufficiently common for it to be considered as the basis for a successful GBS vaccine.

The influence of pre- and post-ovulatory insemination and early pregnancy on the infiltration by cells of the immune system in the sow oviduct

The aim of this study was to investigate the influence of pre- and post-ovulatory insemination and early pregnancy on the distribution of immune cells in the oviduct. Eighteen sows were pre-ovulatory and sixteen sows were post-ovulatory inseminated and slaughtered at different times, 5-6 h after insemination, 20-25 h and approximately 70 h after ovulation, day 11 and day 19. Immediately after slaughter, oviductal samples of three different segments (isthmus, ampulla and infundibulum) were fixed, embedded in plastic resin and stained with toluidine blue or cryofixed and stored in a freezer at -70 degrees C until analysed by immunohistochemistry (pre-ovulatory inseminated sows) with an avidin-biotin peroxidase method. Quantitative and qualitative examinations of oviductal epithelium and subepithelial connective tissue were performed by light microscopy. After pre- or post-ovulatory insemination, neutrophils were not observed in the oviductal epithelium from any of the segments or groups. The numbers of intraepithelial lymphocytes of all sows as well as CD2- and CD3-positive cells of the pre-ovulatory inseminated sows were higher in the infundibulum than in the other segments (p < or = 0.001). In the subepithelial connective tissue of the pre-ovulatory inseminated sows, significantly higher numbers of lymphocytes (p < or = 0.001) and plasma cells (p < or = 0.001) were found in infundibulum than in isthmus. Neutrophils were found mainly in infundibulum, the number approximately 40 h after pre-ovulatory insemination was significantly higher (p < or = 0.05) than in the other groups and segments. Significantly higher numbers of CD2 than CD3-positive cells were found for all groups and segments. In the subepithelial connective tissue of post-ovulatory inseminated sows, the numbers of lymphocytes was higher (p < or = 0.001) at day 19 than up to 50 h after insemination and lower (p < or = 0.001) in isthmus than in ampulla and infundibulum. Neutrophils were found in infundibulum in almost all groups and the number was significantly higher (p < or = 0.05) in the infundibulum up to 50 h after insemination than in other segments. In the oviductal epithelium, no influence of insemination was found on the presence of phagocytes, i.e. neutrophils and macrophages, but on lymphocytes. In the infundibular connective tissue, pre-ovulatory insemination had an effect on neutrophil distribution, indicating an active immune response to insemination in the upper segment. Post-ovulatory insemination changed the oviductal immune cell pattern.

Activity and regulation of factor VIIa analogs with increased potency at the endothelial cell surface

BACKGROUND

Variants of recombinant factor VIIa (rFVIIa) with increased intrinsic activity have been developed to improve efficacy in the treatment of bleeding disorders in the future. The increased potency of FVIIa variants was demonstrated in limited in vitro and in vivo studies. However, further characterization of FVIIa variants is needed to evaluate their potential clinical use.

METHODS

In the present study, we investigated the interactions of two FVIIa variants, FVIIa(Q) and FVIIa(DVQ), with plasma inhibitors, tissue factor pathway inhibitor (TFPI) and antithrombin (AT), and vascular endothelium. TF-FVIIa activity or its inhibition was measured directly in an amidolytic activity assay or for its ability to activate factor X.

RESULTS

Both TFPI and AT/heparin inhibited the FVIIa variants more rapidly than the wild-type (WT) FVIIa in the absence of tissue factor (TF). In the presence of TF, TFPI, TFPI-Xa, and AT/heparin inhibited FVIIa and FVIIa variants at similar rates. Although the WT FVIIa failed to generate significant amounts of FXa on unperturbed endothelial cells, FVIIa variants, particularly FVIIa(DVQ), generated a substantial amount of FXa on unperturbed endothelium. Annexin V fully attenuated the FVIIa-mediated activation of FX on unperturbed endothelial cells. On stimulated human umbilical vein endothelial cells, FVIIa and FVIIa variants activated FX at similar rates, and annexin V blocked the activation only partly. AT/heparin and TFPI-Xa inhibited the activity of FVIIa and FVIIa variants bound to endothelial cell TF in a similar fashion. Interestingly, despite significant differences observed in FXa generation on unperturbed endothelium exposed to FVIIa and FVIIa analogs, no differences were found in thrombin generation when cells were exposed to FVIIa or FVIIa analogs under plasma mimicking conditions.

CONCLUSION

Overall, the present data suggest that although FVIIa variants generate substantial amounts of FXa, they do not generate excessive thrombin on the surface of endothelium.