Urinary interleukin-8 is a biomarker of stress in emergency physicians, especially with advancing age--the JOBSTRESS* randomized trial

Background

Emergency physicians are exposed to greater stress during a 24-hour shift (24 hS) than a 14-hour night shift (14 hS), with an impact lasting several days. Interleukin-8 (IL-8) is postulated to be a chronic stress biomarker. However, no studies have tracked IL-8 over several shifts or used it for monitoring short-term residual stress. The IL-8 response to the shifts may also increase with age. Conveniently, IL-8 can be measured non-intrusively from urine.

Methods

We conducted a shifts-randomized trial comparing 17 emergency physicians’ urinary IL-8 levels during a 24 hS, a 14 hS, and a control day (clerical work on return from leave). Mean levels of IL-8 were compared using a Wilcoxon matched-pairs test. Independent associations of key factors including shifts, stress, and age with IL-8 levels were further assessed in a multivariable generalized estimating equations model.

Results

Mean urinary IL-8 levels almost doubled during and after a 24 hS compared with a 14 hS or a control day. Furthermore, IL-8 levels failed to return to control values at the end of the third day after the shift despite a rest day following the 24 hS. In the multivariable model, engaging in a 24 hS, self-reported stress, and age were independently associated with higher IL-8 levels. A 24 hS significantly increased IL-8 levels by 1.9 ng (p = .007). Similarly, for every unit increase in self-reported stress, there was a 0.11 ng increase in IL-8 levels (p = .003); and for every one year advance in age of physicians, IL-8 levels also increased by 0.11 ng (p = .018).

Conclusion

The 24 hS generated a prolonged response of the immune system. Urinary IL-8 was a strong biomarker of stress under intensive and prolonged demands, both acutely and over time. Because elevated IL-8 levels are associated with cardiovascular disease and negative psychological consequences, we suggest that emergency physicians limit their exposure to 24 hS, especially with advancing age.

Effects of temperature and food supply on the growth of whitefish Coregonus lavaretus larvae in an oligotrophic peri-alpine lake

The relative roles of temperature and food availability on the seasonal and daily growth of whitefish Coregonus lavaretus larvae were investigated in the oligotrophic peri-alpine Lake Annecy, France. During the spring from 2004 to 2007, surface water temperature and density of potential zooplankton prey were monitored, and 2688 larvae were caught and measured. In addition, the daily growth of 130 larvae was estimated retrospectively by investigating the microstructure of their otoliths. Temperature played the predominant role in controlling both seasonal and daily growth of early larvae. In contrast, the abundance of Mesocyclops leuckarti and larval density was only slightly correlated to larval growth, suggesting no food limitation nor strong interindividual competition over the study period. Overall, these findings run counter to concerns about potential food limitation, but sound a warning about the potential impact of climate change on fish ecology and fisheries management.

Effects of haptoglobin polymorphisms and deficiency on susceptibility to inflammatory bowel disease and on severity of murine colitis

BACKGROUND

Haptoglobin (Hp) is a haemoglobin-binding protein with immunomodulatory properties. Its gene (16q22) harbours a common polymorphism with two different alleles: Hp1 and Hp2. Genotype Hp22 has been shown to be over-represented in different immune diseases. Results in Crohn's disease (CD) are contradictory.

AIMS

To determine whether Hp plays a role in inflammatory bowel disease, both genetically and functionally.

METHODS

1061 patients with CD, 755 with ulcerative colitis (UC) and 152 with primary sclerosing cholangitis, as well as 452 healthy controls, were genotyped using touch-down PCR. To confirm association results, 464 CD trios and 151 UC trios were genotyped. Serum Hp concentrations were determined in 62 individuals of different genotype. Colitis was induced in mice with dextran sulphate sodium (DSS) and oxazolone (Oxa). Cytokine production was evaluated by mRNA quantification in colonic tissue and ELISA on supernatants of mesenteric lymph node cells.

RESULTS

Prevalence of Hp2 was higher in CD and UC than in controls. In the confirmatory cohorts, Hp2 was over-transmitted to the affected offspring. Serum Hp concentrations were higher in individuals with genotypes Hp11 and Hp21 than in those with Hp22 (1.38 vs 0.89 g/l). DSS- and Oxa-induced colitis were more severe in Hp-deficient mice than in control mice and accompanied by higher concentrations (although not statistically significantly different) of tissue mRNA for cytokines. Interleukin-17 production was significantly higher in the presence of Hp-deficient serum compared with wild-type serum.

CONCLUSIONS

The Hp gene may play a role in susceptibility to inflammatory bowel disease. Its implication in other immune diseases underscores the common pathways between these diseases. Experimental models of colitis showed that Hp has a protective role in inflammatory colitis, most likely by inhibiting the production of Th1 and Th17 cytokines.

Gut permeability and food allergies

Intestinal permeability is a critical feature of the gastrointestinal epithelium as it must allow an efficient passage of nutrients and restrict the entry of larger molecules, such as protein antigen, in order to facilitate appropriate immune responses towards food antigens. The proper regulation of the epithelial barrier relies on multiple, intricate physiological and immunologic mechanisms, in terms of which recent progresses regarding the cellular and molecular components have been unravelled. In genetically predisposed individuals, breakdown of oral tolerance can occur, leading to the inadequate production of allergen-specific IgE and the recruitment of mast cells in the gastrointestinal mucosa. Under such conditions, the intestinal permeability towards allergen is altered via different mechanisms, with IgE-CD23-mediated transport across the mucosa playing an important amplification role. Additionally, during the effector phase of the allergic reaction, when mast cells degranulate, a series of inflammatory mediators, such as proteases and cytokines, are released and further affects intestinal permeability. This leads to an increase in the passage of allergens and hence contributes to perpetuate the inflammatory reaction. In this review, we describe the importance of properly balanced intestinal permeability in oral tolerance induction and address the processes involved in damaging the intestinal barrier in the sensitized epithelium and during allergic reactions. We conclude by speculating on the effect of increased intestinal permeability on the onset of sensitization towards dietary antigens.

Allergen-specific antibody and cytokine responses, mast cell reactivity and intestinal permeability upon oral challenge of sensitized and tolerized mice

BACKGROUND

Food allergy has reached an epidemic level in westernized countries and although central mechanisms have been described, the variability associated with genetic diversity underscores the still unresolved complexity of these disorders.

OBJECTIVE

To develop models of food allergy and oral tolerance, both strictly induced by the intestinal route, and to compare antigen-specific responses.

METHODS

BALB/c mice were mucosally sensitized to ovalbumin (OVA) in the presence of the mucosal adjuvant cholera toxin, or tolerized by intra-gastric administrations of OVA alone. Antibody titres and cytokines were determined by ELISA, and allergic status was determined through several physiologic parameters including decline in temperature, diarrhoea, mast cell degranulation and intestinal permeability.

RESULTS

OVA-specific antibodies (IgE, IgGs and IgA in serum and feces) were produced in sensitized mice exclusively. Upon intra-gastric challenge with OVA, sensitized mice developed anaphylactic reactions associated with a decline of temperature, diarrhoea, degranulation of mast cells, which were only moderately recruited in the small intestine, and increased intestinal permeability. Cytokines produced by immune cells from sensitized mice included T-helper type 2 cytokines (IL-5, IL-13), but also IL-10, IFN-gamma and IL-17. In contrast, all markers of allergy were totally absent in tolerized animals, and yet the latter were protected from subsequent sensitization, demonstrating that oral tolerance took place efficiently.

CONCLUSION

This work allows for the first time an appropriate comparison between sensitized and tolerized BALB/c mice towards OVA. It highlights important differences from other models of allergy, and thus questions some of the generally accepted notions of allergic reactions, such as the protective role of IFN-gamma, the importance of antigen-specific secretory IgA and the role of mucosal mast cells in intestinal anaphylaxis. In addition, it suggests that IL-17 might be an effector cytokine in food allergy. Finally, it demonstrates that intestinal permeability towards the allergen is increased during challenge.

Thyme and cinnamon extracts induce anion secretion in piglet small intestine via cholinergic pathways

Thymol and cinnamaldehyde, extracted from thyme and cinnamon respectively, have multiple effects on mammalian cells. Although the intestinal mucosa is one of the first tissues they are in contact with when ingested, their effect on intestinal epithelial cells and especially ion secretion has not been established yet. The aim of this study was to investigate the effect of those two substances on electrolyte secretion and absorption across the porcine jejunal epithelium in Ussing chambers. Jejunal tissues from piglets were mounted in Ussing chambers and the short circuit current measured (I(sc)) after addition of thymol or cinnamaldehyde. Thymol and cinnamaldehyde induced a dose-dependent increase is I(sc). The effect of thymol was inhibited in low Cl-, HCO3(-) free or low Cl-/ HCO3(-) free buffers. It was completely blocked when tissues were previously incubated with tetrodotxin and partially inhibited with hexamethonium. Cinnamaldehyde effect was inhibited when HCO3(-) free or low Cl-/ HCO3(-) free buffers were used. It was not affected by tetrodotoxin but reduced by hexamethonium, suggesting direct activation of receptors on epithelial cells. In conclusion, thymol induces Cl- and HCO3(-) secretion via activation of nervous nicotinic receptors while cinnamaldehyde induces HCO3(-) secretion probably via direct activation of nicotinic receptors on epithelial cells.

[Pertrochanteric fractures in elderly subjects aged over 75]

Pertrochanteric fractures constitute a major public health concern. This retrospective multicentric study evaluated outcome after treatment in patients aged over 75 years hospitalized for pertrochanteric fractures over a one year period (May 2004-May 2005). Five University Hospitals in the cities of Angers, Brest, Rennes, Tours, Nantes participated in this evaluation. The quality of the reduction and the position of the osteosynthesis were the two main criteria for good outcome. The type of material implanted had little effect on outcome. The results emphasized the importance of preventing osteoporosis. Fracture prevention and treatment of osteoporosis are crucial, even after fracture.

[Activities of medical practitioners in nursery schools for children under 6 years-old: the expectations of the facilities' directors]

This work aims to describe the activities of nurseries' medical practitioners and the expectations of the nurseries' supervisors. It is based on the analysis of 139 questionnaires received from nursery schools' managers from the Pays de Loire region in 2005. Ninety percent of the nurseries that accommodate children less than six years-old, do employ a medical practitioner. She or he is often a salaried paediatrician with a full-time job or clinical practice, who consults twice a month for two hours and forty minutes in each nursery which employs him/her. Her/his main activity consists of conducting standard medical examinations when children are admitted into the nursery and on-going follow-up of their adaptation and healthy early childhood development. She or he also ensures that hygienic preventive measures are respected in case of an epidemic or other potentially hazardous health situations. Moreover, two-thirds of the establishments offer prevention follow-up for the children, whereas health promotion programmes and interventions are only carried out in just over half of them. Emergency medical procedures are conducted in a quarter of them only. Most of the nursery directors are satisfied with the medical services provided, despite some criticism. They mainly wish that practitioners were more available and more regularly present on-site in order to supply further preventive care, to develop training programmes for other staff members, and to participate in thematic meetings. Encouraging improved synergy between the professionals working in the nurseries, placing child psychologists to work in the facilities and fostering better relationships with the independent medical practitioners would all help the process of development and the evolution of the operational function of the medical practitioners in these structures.

L’utilisation du tabac à chiquer

INTRODUCTION

In France, unlike in the United States and Scandinavia, the use of "smokeless tobacco" (also called "chewing tobacco") was rare, but this habit is starting to expand, especially in the world of sports. At ski championships, for example, it is used as a doping agent. Adolescents in mountain areas are now imitating their competitive-skiing peers.

CASE

A 16-year-old girl living in a ski resort became addicted to the tobacco paste, "Snuss", and consumed 15-20 doses of Snuss daily, together with a dozen cigarettes.

DISCUSSION

"Smokeless tobacco" is emerging as a habit in France, its use encouraged by its discretion, low cost, and rapid induction of addiction. Its growth in Alpine areas requires the urgent development of impact studies to facilitate the organization of information campaigns to treat and prevent its use.

The Spectroscopic Orbit of the Planetary Companion Transiting HD 209458

We report a spectroscopic orbit with period P=3.52433+/-0.00027 days for the planetary companion that transits the solar-type star HD 209458. For the metallicity, mass, and radius of the star, we derive [Fe/H&sqbr0;=0.00+/-0.02, M*=1.1+/-0.1 M middle dot in circle, and R*=1.2+/-0.1 R middle dot in circle. This is based on a new analysis of the iron lines in our HIRES template spectrum and also on the absolute magnitude, effective temperature, and color of the star, and it uses isochrones from four different sets of stellar evolution models. Using these values for the stellar parameters, we reanalyze the transit data and derive an orbital inclination of i=86&fdg;1+/-1&fdg;6. For the planet, we derive a mass of Mp=0.69+/-0.05 MJup, a radius of Rp=1.40+/-0.17 RJup, and a density of rho=0.31+/-0.07 g cm-3.

Use of human sera containing autoantibodies for an immunochemical study of some ribosomal proteins in rat, trout, mussel and fly maggot

Sera from human subjects affected by autoimmune connective tissue diseases and containing antiribosomal autoantibodies were used to analyze by immunoblotting ribosomal proteins from trout (Oncorhynchus mykiss) liver, mussel (Mytilus edulis) hepatopancreas and whole fly maggots (Calliphora vomitoria). As usual in medical analysis of autoantibodies, the reference antigen preparation was extracted from rat liver. With the used sera, six known ribosomal proteins from rat liver were characterized: P0, P1, P2, p30, p25 and p20. These six proteins were all targeted in trout; moreover an important 40 kDa fraction, undetectable in rat pattern, was seen. p30 and p20 were undetected in mussel and fly maggot; but p25, undetected in mussel, is clearly characterized in fly maggot. The interest of these data to infer phylogenic relationships is discussed.

[Activities of twelve enzymes in the blood plasma of rainbow trout and tench subjected to various forms of thermal disturbance]

The levels of ornithine carbamyl transferase, acid phosphatase, alkaline phosphatase, leucine amino peptidase, creatine kinase, amylase, glutamic oxalacetic transaminase, glutamic pyruvic transaminase, lactate deshydrogenase, hydroxybutyrate deshydrogenase, glutamate deshydrogenase and malate deshydrogenase were determined in the plasma of Rainbow Trout and Tench submitted to water temperature increases. In the Rainbow Trout a thermal shock from 12 to 21 degrees, increases activities of some enzymes while temperature increase up to pre-mortem stage causes very important changes in enzymatic levels. In the Tench a thermal shock from 12 to 28 degrees causes more changes of enzymatic activities than a shock from 12 to 25 degrees. In Tench acclimated to 25 degrees, various enzyme levels are increased in comparison with 12 degrees control animals. A high potassium level in water causes complex changes in enzyme levels. The most sensitive enzymes to thermal disturbance are GOT and GPt transaminases which increase whatever the aggression form, amylase when thermal disturbance is moderate, alkaline phosphatase and malate deshydrogenase in case of strong thermal stress. The study of these enzymes is recommended for watching the state of fishes living in artificially heated waters.

[Obtaining an anti-trout (Salmo gairdneri Rich.) immunoglobulin specific serum from rabbits immunized with the slowest serum fraction isolated in polyacrylamide gel electrophoresis]

Rabbits were immunized with the slowest fraction obtained by polyacrylamide gel electrophoresis of normal Trout serum previously cleared of lipoproteins. The antiserum thus obtained reacts specifically with Trout immunoglobulin. This was verified by inhibiting the neutralization of Infectious Pancreatic Necrosis Virus by Trout antibodies, and by comparing it in immunoelectrophoresis with a rabbit antiserum previously obtained by immunization with Trout antibodies-Dinitrophenol-Haemocyanin immune complexes.