Pre-B cell colony enhancing factor (PBEF/NAMPT/Visfatin) and vascular endothelial growth factor (VEGF) cooperate to increase the permeability of the human placental amnion.

Fluid efflux across the region of the amnion overlying the placenta is an essential component of the intramembranous absorption pathway that maintains amniotic fluid volume homeostasis. Dysregulation of this pathway may result in adverse pregnancy outcomes, however the factors controlling amnion permeability are unknown. Here, we report a novel mechanism that increases placental amnion permeability. Pre-B Cell Colony Enhancing Factor (PBEF) is a stress-responsive cytokine expressed by the human amnion, and is known to induce Vascular Endothelial Growth Factor (VEGF) production by other cell types. Interestingly, VEGF is up-regulated in the ovine amnion when intramembranous absorption is augmented. In this study, we show that PBEF induced VEGF secretion by primary human amniotic epithelial cells (AEC) derived from the placental amnion, as well as from the reflected amnion that lines the remainder of the gestational sac. Further, PBEF treatment led to the increased expression of VEGFR2 in placental AEC, but not reflected AEC. To test the hypothesis that PBEF and VEGF increase placental amnion permeability, we monitored the transfer of 2',7'-dichlorofluorescein (DCF) from the fetal to the maternal side of human amnion explants. A treatment regimen including both PBEF and VEGF increased the rate of DCF transfer across the placental amnion, but not the reflected amnion. In summary, our results suggest that by augmenting VEGFR2 expression in the placental amnion, PBEF primes the tissue for a VEGF-mediated increase in permeability. This mechanism may have important implications in amniotic fluid volume control throughout gestation.

Precise extraction of the induced polarization in the 4He(e,e'p)3H reaction.

We measured with unprecedented precision the induced polarization P(y) in (4)He(e,e'p)(3)H at Q(2)=0.8 and 1.3 (GeV/c)(2). The induced polarization is indicative of reaction-mechanism effects beyond the impulse approximation. Our results are in agreement with a relativistic distorted-wave impulse approximation calculation but are overestimated by a calculation with strong charge-exchange effects. Our data are used to constrain the strength of the spin-independent charge-exchange term in the latter calculation.

Cough hypersensitivity syndrome: a distinct clinical entity.

We postulate that most patients with chronic cough have a single discrete clinical entity: cough hypersensitivity syndrome. We constructed a questionnaire that elicits the major components of the syndrome. Here we describe the validation of this questionnaire. Following iterative development, the Hull Airway Reflux Questionnaire (HARQ) was administered to patients and normal volunteers. It is self-administered and comprises 14 items with a maximum score of 70. Unselected patients were recruited sequentially from the Hull Cough Clinic. Preclinic questionnaires were compared with those obtained at the clinic. Responsiveness was assessed 2 months after the clinic visit. One hundred eighty-five patients and 70 normal volunteers were included in this study. There was a marked difference in HARQ scores between patients with chronic cough and normal volunteers. The sensitivity (94%) and specificity (95%) of the HARQ was high, with an area under the ROC curve of 0.99. All items of the scale significantly correlated positively with others in the scale and with the total score. On repeatability testing using Cohen's kappa with quadratic weights, significant agreement was noted for all items. Good correlation was observed between the total scores (r = 0.78). The questionnaire was also responsive to treatment; the minimum clinically significant change was estimated to be 16 points. We have demonstrated the HARQ to have good construct and criterion validity. It is both reproducible and responsive to change. It can be used as a diagnostic instrument and demonstrates that chronic cough represents a single coherent entity: cough hypersensitivity syndrome.

Polarization transfer in the 4He(e,e'p)3H reaction at Q2=0.8 and 1.3 (GeV/c)2.

Proton recoil polarization was measured in the quasielastic 4He(e,e'p)3H reaction at Q{2}=0.8 and 1.3 (GeV/c){2} with unprecedented precision. The polarization-transfer coefficients are found to differ from those of the 1H(e,e'p) reaction, contradicting a relativistic distorted-wave approximation and favoring either the inclusion of medium-modified proton form factors predicted by the quark-meson coupling model or a spin-dependent charge-exchange final-state interaction. For the first time, the polarization-transfer ratio is studied as a function of the virtuality of the proton.

Stretch and inflammation-induced Pre-B cell colony-enhancing factor (PBEF/Visfatin) and Interleukin-8 in amniotic epithelial cells.

Preterm birth continues to be a growing problem in the USA. Although approximately half of preterm births are caused by intrauterine infection, uterine over-distension is also a cause. In this study we have compared the effects of static stretch, cyclic stretch/release and an inflammatory stimulus alone and in combination on the expression of Pre-B cell colony-enhancing factor (PBEF) and IL-8 in primary amniotic epithelial cells (AEC). We then sought to identify some of the mechanism(s) by which these cells respond to stretching stimuli. We show that cyclic stretch/release is a more robust stimulus for both PBEF and IL-8 than static stretch. Cyclic stretch/release increased both intracellular and secreted PBEF and a combination of both types of stretch was a more robust stimulus to PBEF that IL-8. However, when an inflammatory stimulus (IL-1beta) was added to either kind of stretch, the effect on IL-8 was much greater than that on PBEF. Thus, different kinds of stretch affect the expression of these two cytokines from AEC, but inflammation is a much stronger stimulus of IL-8 than PBEF, agreeing with its primary role as a chemokine. Although the AEC showed morphological signs of increased cellular stress during stretching, blocking reactive oxygen species (ROS) had little effect. However, blocking integrin binding to fibronectin significantly reduced the responses of both PBEF and IL-8 to cyclic stretch/release. The increased PBEF, both intracellularly and secreted, suggests that it functions both to increase the metabolism of the cells, at the same time as stimulating further the cytokine cascade leading to parturition.

Chronic stretching of amniotic epithelial cells increases pre-B cell colony-enhancing factor (PBEF/visfatin) expression and protects them from apoptosis.

In normal pregnancy, the fetal membranes become increasingly distended towards term and in multifetal gestations they become over-distended. Apoptosis of the amniotic epithelium increases with advancing gestation and may contribute to fetal membrane weakening and rupture. The effects of chronic static stretching for 36h have been investigated using primary amniotic epithelial cells. Pre-B cell colony-enhancing factor (PBEF) is a stretch-responsive cytokine and expression of its gene, intracellular and secreted protein were all significantly increased by 4h and its secretion sustained over 36h, contrasting with the rapid increase and decline in expression of IL-8. Increased expression of SIRT1 and decreased p53 paralleled the changes in PBEF, are known to be responsive to PBEF, and contribute to cell survival. Distension had no effects on proliferation or necrosis but protected the cells from apoptosis, knocking-down PBEF with antisense probes abrogated this protective effect. There was increased immunostaining of PBEF in the compact layer of the amnion in multifetal tissues and significantly fewer apoptotic amniotic epithelial cells. These results show that chronic stretching of the amniotic epithelial cells increases PBEF expression, which protects them from apoptosis.

Stress-induced cytokine responses and central adiposity in young women.

BACKGROUND: Evidence suggests that people who are more responsive to psychological stress are at an increased risk of developing obesity. However, the biological mechanisms underlying this phenomenon are poorly understood. The cytokines leptin, interleukin-1 receptor antagonist (IL-1Ra) and interleukin-6 (IL-6) play a key role in fat metabolism and abnormal circulating levels of these proteins have been reported in obese people and in individuals subject to stress. OBJECTIVE: This study investigated whether cytokine responses to acute mental stress are associated with adiposity in healthy young women. DESIGN AND SUBJECTS: A laboratory study of 67 women, aged 18-25 years, recruited from University College London. MEASUREMENTS: Height, weight and waist circumference were measured and body fat mass was estimated by bioelectrical impedance body composition analysis. Laboratory mental stress testing was carried out and blood pressure and heart rate were recorded at baseline, during two moderately challenging tasks (Stroop and speech) and during recovery 40-45 min post-stress. Blood samples taken at baseline, immediately post-stress and 45 min post-stress, were used for assessment of circulating cytokines. Saliva samples taken throughout the session were assessed for cortisol. RESULTS: Women who had larger cytokine responses to stress were more abdominally obese than women with smaller cytokine stress responses. Specifically, there was a positive correlation between waist circumference and stress-induced increases in plasma levels of leptin (r=0.35, P<0.05) and IL-1Ra responses (r=0.29, P<0.05). There was also a significant positive correlation between prolonged diastolic blood pressure responses to stress and measures of total and abdominal obesity (r=0.28-0.33, P<0.05). CONCLUSION: Increased cytokine production could be a mechanism linking stress and abdominal obesity.

Inoprotection: the perioperative role of levosimendan.

Levosimendan is emerging as a novel cardioprotective inotrope. Levosimendan augments myocardial contractility by sensitising contractile myofilaments to calcium without increasing myosin adenosine triphosphatase activity or oxygen consumption. Levosimendan activates cellular adenosine triphosphate-dependent potassium channels, a mechanism which is postulated to protect cells from ischaemia in a manner similar to ischaemic preconditioning. Levosimendan may therefore protect the ischaemic myocardium during ischaemia-reperfusion as well as improve the contractile function of the heart. Adenosine triphosphate-dependent potassium channel activation by levosimendan may also be protective in other tissues, such as coronary vascular endothelium, kidney and brain. Clinical trials in patients with decompensated heart failure and myocardial ischaemia show levosimendan to improve haemodynamic performance and potentially improve survival. This paper reviews the known pharmacology of levosimendan, the clinical experience with the drug to date and the potential use of levosimendan as a cardioprotective agent during surgery.

The cardiovascular effects of adrenaline, dobutamine and milrinone in rabbits using pressure-volume loops and guinea pig isolated atrial tissue.

This study evaluated the effects of milrinone, adrenaline and dobutamine with pressure-volume loops and isolated atrial tissue. Agonist dose-response curves to incremental drug infusions were acquired in 11 anesthetised rabbits using pressure-volume loops and preload recruitable stroke work indicated contractility. Agonist concentration-response curves were completed in eight guinea pig isolated atria, for effects on atrial rate and force. Adrenaline and dobutamine increased contractility (P = 0.006 and 0.044), whereas milrinone did not (P = 0.895). Only adrenaline increased myocardial stiffness (P < 0.001). Milrinone decreased vascular resistance (P < 0.001) and elicited the greatest fall in mean arterial pressure (P < 0.001) and increased ejection fraction (P < 0.001). Adrenaline decreased heart rate (P < 0.001), whereas dobutamine and milrinone increased it (P = 0.006 and 0.011). Milrinone increased the force of left atrial contraction, but its inotropic effect was weak and significantly less than with dobutamine and adrenaline (P < 0.001). Adrenaline acted as an inoconstrictor, dobutamine an inodilator and milrinone predominantly a vasodilator

Averting iatrogenic hypoglycemia through glucose prediction in clinical practice: progress towards a new procedure in diabetes.

BACKGROUND: Hypoglycemia is a risk factor common to all insulin therapy. The hypothesis is that efforts to reduce or prevent this adverse side effect may fail because providers generally lack the resources to predict not only future blood glucose levels but also future risks of hypoglycemia. This lack has been remedied. A controlled study was undertaken to test the hypothesis. METHODS: Twenty-two insulin dependent subjects suffering more than one (1) episode/week of hypoglycemia with similar insulin regimens, similar diabetes education and similar self-management training participated in this study. For all subjects, a remote monitoring resource (registry and database) was used to capture daily SMBG and afford a return path for provider interventions and decision support. Identical telemedical methods were used which differed only for the provider either by the presence (prediction group) or by the absence (control group) of an on-screen, visual display of predicted glycemia and predicted risks of hypoglycemia. The study lasted 2 months. RESULTS: Over an average of 41 days from baseline to follow up and while using the glycemic prediction resource, providers intervened more effectively in the prediction group reducing rates of hypoglycemia nine-fold (P<0.0001) and insulin therapy by just -9 U/day (P<0.01). Mean pre-meal glycemia was not compromised. Over 61 days from baseline to final follow up but without glycemic predictions in the control group, providers' interventions were less effective and resulted in no net changes in rates of hypoglycemia, daily insulin therapy, or mean pre-meal glycemia. CONCLUSIONS: Given knowledge of future glycemia and future risks of hypoglycemia, providers in clinical practice can now avert iatrogenic hypoglycemia in less than 2 months. A shared diabetes data center furnishing remote data capture and decision support is fundamental to the implementation of this as a new clinical procedure in diabetes.

Scaling tests of the cross section for deeply virtual Compton scattering.

We present the first measurements of the e[over -->]p-->epgamma cross section in the deeply virtual Compton scattering (DVCS) regime and the valence quark region. The Q(2) dependence (from 1.5 to 2.3 GeV(2)) of the helicity-dependent cross section indicates the twist-2 dominance of DVCS, proving that generalized parton distributions (GPDs) are accessible to experiment at moderate Q(2). The helicity-independent cross section is also measured at Q(2)=2.3 GeV(2). We present the first model-independent measurement of linear combinations of GPDs and GPD integrals up to the twist-3 approximation.

Physiological correlates of cognitive functioning in an elderly population.

Cognitive decline in old age is not universal or inevitable. Associations have been observed with neuroendocrine function, but the relevance of other physiological processes is unclear. We predicted that impairment of memory in an ageing population would be related to the dysregulation of neuroendocrine and cardiovascular responses. One hundred and thirty-nine participants (65-80 years) were recruited from general practice in London. Two standardised verbal paired-associates recall tasks were administered in order to determine declarative memory performance, and a fluid intelligence task (matrix reasoning) was also performed. Salivary cortisol samples were collected every 10 min, while blood pressure and heart rate were measured before, during and after each task. Illness history and medication use were obtained from medical records. Multiple linear regression analysis, adjusted for age, gender, education, chronic illness, and medication use, revealed that cortisol responses were inversely related to memory performance. Additionally, superior memory was associated with more effective post-task recovery of heart rate (in both men and women) and diastolic blood pressure recovery in men. Cardiovascular recovery effects were independent of covariates, and of levels of heart rate and blood pressure measured during tasks themselves. These associations were also independent of subjective ratings of stress and perceived performance. Neither neuroendocrine nor cardiovascular responses were related to performance of the reasoning task. We conclude that memory in the elderly is associated both with hypothalamic-pituitary-adrenocortical function and cardiovascular regulation. Disturbances of neuroendocrine and hemodynamic function may be related to greater vulnerability to cognitive decline.

Acute inflammation and negative mood: mediation by cytokine activation.

Inflammatory diseases are commonly associated with depressed mood. This association may be influenced by the production of proinflammatory cytokines. Accordingly, we assessed whether cytokine levels and mood (measured with the profile of mood states) could be altered by a mild, non-sickness inducing, acute inflammatory stimulus. Using a randomised placebo-controlled, double-blind design, 30 healthy male volunteers were injected with Salmonella typhi vaccine or placebo. Assessments of mood, symptoms of illness and temperature were made at baseline and at 1.5, 3, and 6 h post-injection. Plasma concentrations of interleukin-6 (IL-6), interleukin-1 receptor antagonist (IL-1Ra), and tumour necrosis factor-alpha (TNF-alpha) were assessed at baseline and 3 h post-injection. No significant symptoms of illness were reported in either group. Mood was more negative following injection in the vaccine than the placebo group, and the vaccine group experienced a 106% increase in IL-6 concentration. Negative changes in mood following injection were significantly correlated with increases in IL-6 production. No changes in TNF-alpha or IL-1Ra concentration were recorded in either group. It is concluded that S. typhi vaccination may be a useful model of mild inflammatory challenge, producing a significant transient cytokine-induced decrease in mood in the absence of any febrile response. Implications for depressed mood in physical illness are discussed.

Dietary intake, physical activity, and obesity in women with polycystic ovary syndrome.

OBJECTIVE: To determine whether dietary intake and physical activity contribute to obesity in women with polycystic ovary syndrome (PCOS). DESIGN: Case-control study. SUBJECTS: A total of 84 cases and 79 neighborhood controls of similar age. MEASUREMENTS: Fasting insulin, body mass index (BMI, kg/m2), waist/hip ratio, Block Food Frequency Questionnaire, Paffenbarger Physical Activity Questionnaire. RESULTS: Although women with PCOS had a higher BMI than control women, an overall comparison of women with and without PCOS showed no significant difference in dietary intake. However, stratification by BMI revealed that lean women with PCOS reported significantly lower energy intake than lean women without PCOS. CONCLUSION: Differences in dietary intake and physical activity alone are not sufficient to explain differences in weight between women with and without PCOS. Further research is necessary to determine the relative contributions of lifestyle factors and metabolism to obesity in PCOS.

Polarization transfer in the 4He(e-->,e'p-->)3H reaction up to Q2=2.6 (GeV/c)2.

We have measured the proton recoil polarization in the 4He(e-->,e(')p-->)4H reaction at Q(2)=0.5, 1.0, 1.6, and 2.6 (GeV/c)(2). The measured ratio of polarization transfer coefficients differs from a fully relativistic calculation, favoring the inclusion of a medium modification of the proton form factors predicted by a quark-meson coupling model. In addition, the measured induced polarizations agree reasonably well with the fully relativistic calculation indicating that the treatment of final-state interactions is under control.

Physiologically based modelling of inhibition of metabolism and assessment of the relative potency of drug and metabolite: dextromethorphan vs. dextrorphan using quinidine inhibition.

AIMS: To define the relative antitussive effect of dextromethorphan (DEX) and its primary metabolite dextrorphan (DOR) after administration of DEX. METHODS: Data were analysed from a double-blind, randomized cross-over study in which 22 subjects received the following oral treatments: (i) placebo; (ii) 30 mg DEX hydro-bromide; (iii) 60 mg DEX hydro-bromide; and (iv) 30 mg DEX hydro-bromide preceded at 1 h by quinidine HCl (50 mg). Cough was elicited using citric acid challenge. Pharmacokinetic data from all non-placebo arms of the study were fitted simultaneously. The parameters were then used as covariates in a link PK-PD model of cough suppression using data from all treatment arms. RESULTS: The best-fit PK model assumed two- and one-compartment PK models for DEX and DOR, respectively, and competitive inhibition of DEX metabolism by quinidine. The intrinsic clearance of DEX estimated from the model ranged from 59 to 1536 l x h(-1), which overlapped with that extrapolated from in vitro data (12-261 l x h(-1)) and showed similar variation (26- vs. 21-fold, respectively). The inhibitory effect of quinidine ([I]/Ki) was 19 (95% confidence interval of mean: 18-20) with an estimated average Ki of 0.017 microM. Although DEX and DOR were both active, the potency of the antitussive effect of DOR was 38% that of DEX. A sustained antitussive effect was related to slow removal of DEX/DOR from the effect site (ke0 = 0.07 h(-1)). CONCLUSIONS: Physiologically based PK modelling with perturbation of metabolism using an inhibitor allowed evaluation of the antitussive potency of DOR without the need for separate administration of DOR.

The placebo response to citric acid-induced cough: pharmacodynamics and gender differences.

Characteristics of the response to placebo in a citric acid-induced cough challenge were investigated as part of a randomized, double-blind crossover trial to assess the antitussive effect of dextromethorphan. Baseline cough responses were established on two occasions in 22 healthy subjects. They received 60 ml placebo antitussive syrup and cough frequency following five inhalations of 10% citric acid over 5 min was measured at regular intervals up to 12 h. Response-time models of varying complexity were used to describe the placebo cough suppression data. The cough response to placebo was also compared to that of the untreated state. The placebo cough response was best characterized by a non-linear increase in cough suppression up to a maximum reduction of 1.6 coughs from baseline at 4-4.5 h, followed by a non-linear return to baseline. The cough response in the untreated state was not different from that of placebo (P=0.99). Females coughed more frequently than males (median number of coughs=10.5 vs. 9.0, respectively P<0.001; Mann-Whitney U test), and adaptation to the cough stimulus was significantly more rapid in females (P<0.025). Accordingly, in trials that use citric acid-induced cough, gender should be considered in study design, particularly in relation to the timing of measurements.

Interplay of biomechanical constraints and kinematic strategies in selecting arm postures.

In this study, the authors examined the interplay between biomechanics and control strategies in the resolution of excess degrees of freedom at the joint level. Seven participants made aimed arm movements from 30 starting points and several starting postures to targets. Final arm postures for movements to a target exhibited substantial joint angle variation. Through regression modeling and by comparing observed final arm postures with biomechanically plausible postures, the authors identified 3 kinematic strategies: (a) Maintain deviations from the average angle at the starting point to the joint's final posture; (b) make torso rotations that are a fixed proportion of shoulder rotations; and (c) adopt a characteristic combination of 4 wrist-positioning approaches. The results demonstrated that kinematic strategies can account for substantial variance in final arm postures, if one takes into account 2 types of individual differences-those that arise inevitably from biomechanical constraints and those that reflect choices in movement strategy.

In vivo regulation of the beta-myosin heavy chain gene in hypertensive rodent heart.

The main goal of this study was to examine the transcriptional activity of different-length beta-myosin heavy chain (beta-MHC) promoters in the hypertensive rodent heart using the direct gene transfer approach. A hypertensive state was induced by abdominal aortic constriction (AbCon) sufficient to elevate mean arterial pressure by approximately 45% relative to control. Results show that beta-MHC promoter activity of all tested wild-type constructs, i.e., -3500, -408, -299, -215, -171, and -71 bp, was significantly increased in AbCon hearts. In the normal control hearts, expression of the -71-bp construct was comparable to that of the promoterless vector, but its induction by AbCon was comparable to that of the other constructs. Additional results, based on mutation analysis and DNA gel mobility shift assays targeting betae1, betae2, GATA, and betae3 elements, show that these previously defined cis-elements in the proximal promoter are indeed involved in maintaining basal promoter activity; however, none of these elements, either individually or collectively, appear to be major players in mediating the hypertension response of the beta-MHC gene. Collectively, these results indicate that three separate regions on the beta-MHC promoter are involved in the induction of the gene in response to hypertension: 1) a distal region between -408 and -3500 bp, 2) a proximal region between -299 and -215 bp, and 3) a basal region within -71 bp of the transcription start site. Future research needs to further characterize these responsive regions to more fully delineate beta-MHC transcriptional regulation in response to pressure overload.

A comparative study of buttressed versus nonbuttressed staple line in pulmonary resections.

BACKGROUND: Prolonged air leak is the major limiting factor in early hospital discharge following pulmonary resection. The purpose of this study was to determine whether the use of bovine pericardial strips as a buttress along the lung staple line would decrease air leaks and hospital stay after lobectomy and segmentectomy. METHODS: This was a multicenter trial consisting of 80 patients undergoing pulmonary resection, randomly assigned to the control group (40 patients) or treatment group (40 patients). The treatment group had reinforcement with bovine pericardium. RESULTS: No statistical differences were noted in the mean intensive care unit length of stay (p = 0.9), number of days with a chest tube (p = 0.6), or total length of stay (p = 0.24). Increased air leak duration was associated with assignment to the control group (r = 0.27, p = 0.02). The mean duration of air leak was 2 days and the mean time to chest tube removal was 5.9 days in patients with a buttressed staple line compared to 3 days and 6.3 days, respectively, for patients with nonbuttressed staple lines. CONCLUSIONS: Within the data of this study, no statistical differences were noted between buttressed and nonbuttressed patients. However, the trend toward shortened air leak time and tube removal time was apparent in the buttressed group. With greater number of patients studied, it is likely that the cost of bovine pericardium would be justified by shorter air leak duration and hospitalization.