Sunday, 29 March 2015

Interesting new paper: Methodological Considerations for Hair Cortisol Measurements in Children

Methodological Considerations for Hair Cortisol Measurements in Children 

Abstract
Background:
Hair cortisol levels are used increasingly as a measure for chronic stress in young children. We propose modifications to the current methods used for hair cortisol analysis to more accurately determine reference ranges for hair cortisol across different populations and age groups.

Methods:
The authors compared standard (finely cutting hair) vs. milled methods for hair processing (n=16), developed a 4-step extraction process for hair protein and cortisol (n=16), and compared liquid chromatography-mass spectrometry (LCMS) vs. ELISA assays for measuring hair cortisol (n=28). The extraction process included sequential incubations in methanol and acetone, repeated twice. Hair protein was measured via spectrophotometric ratios at 260/280 nm to indicate the hair dissolution state using a BioTek® plate reader and dedicated software. Hair cortisol was measured using an ELISA assay kit. Individual (n=13), pooled hair samples (n=12) with high, intermediate, and low cortisol values and the ELISA assay internal standards (n=3) were also evaluated by LCMS.

Results:
Milled and standard methods showed highly correlated hair cortisol (rs=0.951, p<0.0001) and protein values (rs=0.902, p=0.0002), although higher yields of cortisol and protein were obtained from the standard method in 13/16 and 14/16 samples respectively (p<0.05). Four sequential extractions yielded additional amounts of protein (36.5%, 27.5%, 30.5%, 3.1%) and cortisol (45.4%, 31.1%, 15.1%, 0.04%) from hair samples. Cortisol values measured by LCMS and ELISA were correlated (rs=0.737; p<0.0001), although cortisol levels (median [IQR]) detected in the same samples by LCMS (38.7 [14.4, 136] ng/ml) were lower than by ELISA (172.2 [67.9, 1051] ng/ml). LCMS also detected cortisone, which comprised 13.4% (3.7%, 25.9%) of the steroids detected.

Conclusion:
Methodological studies suggest that finely cutting hair with sequential incubations in methanol and acetone, repeated twice, extracts greater yields of cortisol than does milled hair. Based on these findings, at least three incubations may be required to extract most of the cortisol in human hair samples. In addition, ELISA-based assays showed greater sensitivity for measuring hair cortisol levels than LCMS-based assays.

Salimetrics offers Hair Cortisol Analysis at our Cambridge Laboratory, should you wish to learn more e mail: europe@salimetrics.com in addition you may wish to use the following links for more information on this growing technology











Monday, 16 March 2015

Salimetrics will again this year sponsor and exhibit at the BPS Psychobiology Section, Annual Conference - Low Wood Windermere, 2nd to 4th September 2015



The BPS Psychobiology Section, Annual Conference, Low Wood Windermere

Low Wood Hotel, overlooking Lake Windermere has fantastic conference and dining facilities, well-equipped en-suite rooms, a health spa and water-sport facilities. It is also only a short distance from the Langdale pikes for beautiful walks and breath-taking views


"where the science is as good as the view"

The meeting is open to all researchers and scientists interested in psychobiology, providing a forum for networking, showcasing research findings and keeping up to date with the latest developments in the field.

Features of the meeting this year include:

Outstanding guest lecturers: 



Professor Michael Maier

Professor Maier is a Consultant Psychiatrist, Director of Medical Education and Head of London School of Psychiatry. He is the Curator of the Corsellis Brain Collection. The collection contains a large number of brains from patients who had psychiatric and neurodegenerative illnesses, but also a series of brains from patients who did not have any brain disease and who therefore provide a very useful control population.






Professor Brian Hughes

Professor Hughes, of the School of Psychology at the National University of Ireland, Galway. His research and publications have focused on psychological stress (particularly its impact on cardiovascular psychophysiology, immunity, and health) and on psychosocial moderators of stress processes (such as social support, cognition, and personality). His work on how the human cardiovascular response habituates across repeated stress exposures has been extensively cited. He also writes widely on the psychology of empiricism and of empirically disputable claims, especially as they pertain to science, health, and medicine.

Non-parallel oral and poster sessions

Two free places for postgraduate students (includes registration and accommodation)
One free undergraduate student place via the undergraduate project prize sponsored by Salimetrics (includes registration and accommodation)

Special 24 hour event for postgraduates at the very competitive price of £62.40
Conference meal, late bar and entertainment on Thursday 3rd September 2015

Submissions
Submissions are invited for the Psychobiology Section Annual Scientific Meeting 2015.
If you are interested in presenting an oral presentation or poster at the conference then please make your submission via the the submissions webpage icon by 23:59 Friday 10th July 2015.

Two free (sponsored) places for Postgraduate Students
The Section is funding two free places at our Annual Scientific Meeting (ASM) for registered postgraduate students. Postgraduates wishing to be awarded one of these places should submit a summary (maximum 1,000 words) concerning the work from which their submission arises in addition to an abstract. Please submit the summary to Dr Richard Stephens at r.stephens@keele.ac.uk email icon .

Entries for these places must be received by 23:59 on 10th July 2015. However, should any places remain unfilled beyond this date then at the discretion of the committee the additional awards may be made on a first come first served basis. These awards cover the registration fee and accommodation at the Low Wood.



Wednesday, 11 March 2015

Salimetrics to Exhibit at the 20th Annual Conference, European College of Sport Science (ECSS) , 24 to 27 June Malmo, Sweden



Salimetrics will for the fourth time be exhibiting at the ECSS Meeting  this year in the lovely city of Malmo where some 3,000 delegates are expected to attend

Stop by the Salimetrics Booth and we will talk you though the use of Salivary Assays in Sport

For 2015, the multidisciplinary ECSS Congress will be celebrating its 20th anniversary. The 2015 congress theme of Sustainable Sport will permeate the academic programme as well as the arrangements: the three universities co-hosting the event all emphasise sustainability in education and research, and will work together with the City of Malmö, a fair trade city, to make ECSS 2015 a sustainable sports congress. 

The Öresund Region (Malmö, Copenhagen and Lund) is an academically vital area with 150 000 university students and more than 12 000 researchers, among them top class researchers within the many different areas of Sport Sciences and Sport Studies.

Link to Conference Website




Salimetrics is regarded as the World Leader in Saliva Assay Technology and is currently involved with Elite Sportspeople from many disciplines; we have strong relationships with the top Universities within this field and can guide you to the right people to ensure performance is maximized. Our offices can be located Globally

The value of saliva monitoring in sport
The easy, stress-free, non-invasive nature of saliva collection makes it one of the most accessible body fluids and it has been shown to have potential value in studying normal human physiology as well as pathology. The measurement of salivary hormone levels by rapid, sensitive enzyme linked immunosorbent assay (ELISA) techniques is a valuable clinical and research tool for several steroid hormones (e.g. cortisol, testosterone, oestriol, progesterone, dehydroepiandrosterone,). The concentration of these steroid hormones in saliva reflects their free concentration in serum or plasma. The levels of other variables such as immunoglobulin A can also provide useful information about the status of mucosal immunity which is depressed by prolonged physical or psychological stress. The measurement of the concentration of a plasma protein such as transferrin in saliva can be used to exclude samples contaminated by blood which is critical if valid conclusions are to be drawn from salivary hormone data. At Loughborough University, sport scientists have long been using salivary markers as indicators of the stress response to exercise, both in studies examining the impact of acute exercise on immunoendocrine responses and to monitor athletes, including professional footballers, over the course of a competitive season. In conjunction with the use of stress and mood state questionnaires, salivary measures can provide useful information for the sport scientist, team doctor and coach to evaluate the impact of training and competition on the athlete’s immune and endocrine systems. The measurement of salivary immunoglobulin A, cortisol and testosterone have proved useful in this regard. Stressed athletes exhibit depressed levels of immunoglobulin A and an elevated cortisol/testosterone ratio. Recently, this approach has been applied to the monitoring of premier league footballers over the course of the season. While the manager may not use this information to directly inform his team selection, it may prove useful to identify players who are not coping well with stress, allowing appropriate training, psychological, nutritional or medicinal interventions to take place to reduce the chance of player burnout.

Salivary IgA:  What is it and why measure it?
Heavy schedules of training and competition appear to increase the risk of upper respiratory tract infections (URTI), such as sore throats, colds, chest infections and ‘flu (see article by Fahlmann & Engels 2005).  Insufficient recovery from these illnesses can lead to recurrent infectious episodes that could cost a player days or even weeks of vital training and could ultimately make or break a successful season for an individual or a team. Although there are several possible mechanisms for these increased episodes of infection, it has been suggested that URTI may result from a reduction in the levels of the main antibody found in saliva, tears and mucous: immunoglobulin A (IgA).  Saliva and mucosal secretions protect the lining of the oral cavity through a mechanical washing effect and play an important role as the first-line of defence against potential pathogens entering via the mouth.  IgA acts to prevent the replication of viruses and inhibits viral and bacterial attachment to the mucosal lining of the mouth, throat and upper respiratory tract.

Resting levels of salivary IgA (s-IgA) have been closely associated with episodes of URTI, with higher levels of s-IgA associated with a lower incidence of URTI and lower levels of s-IgA associated with recurrent URTI both in the general population and in elite athletes.  Furthermore, long-term (months) of exercise training appears to have a ‘snowball’ effect on s-IgA responses; resting s-IgA concentration has been shown to fall during a 7-month training season in elite swimmers and an higher incidence of URTI has been reported in elite swimmers undertaking intensive training who have low s-IgA levels (Gleeson et al 1995).  In addition to the physiological stress placed upon an individual during heavy schedules of training and competition, psychological stress also appears to influence s-IgA concentration, with higher levels of mental stress associated with lower s-IgA concentration. Since s-IgA and episodes of URTI appear to be related, measuring resting s-IgA levels provides information on resting levels of mucosal immunity and changes in this marker of immune function as the season progresses can be used as an indicator of stress. We already have evidence that s-IgA levels change during the course of a season in English premier league players.

Are there other useful ways of assessing immune function?
There are other measures of immune function but all of these require blood sampling. Numbers of the different types of white blood cells can be measured that can give some information about on-going infections or allergies. Some routine haematology tests can tell you a player’s haemoglobin concentration and the average size and number of his red blood cells. These simple tests can identify players who are anaemic and the additional measurement of a protein called ferritin in blood serum is a good indicator of iron stores. Iron deficiency is the most common cause of anaemia and this condition will almost certainly result in underperformance in any sport where endurance is important. More sophisticated and expensive tests can be used to assess lymphocyte subsets, activation markers and cell functions.

Salivary cortisol and testosterone
As players become more stressed through repeated match play, training and inadequate recovery the secretion of the adrenal glucorticoid hormone cortisol is increased whereas that of the sex steroid testosterone falls. The ratio of cortisol to testosterone is therefore a sensitive index of stress. A published example of results from a study on England rugby union players (Gleeson et al 2007) illustrates the potential value of regular monitoring of players during critical stages of the season.

References:
Fahlman MM,  Engels H-J (2005). Mucosal IgA and URTI in American college football players: A year longitudinal study. Med Sci Sports Exerc 37: 374-380.

Gleeson M, McDonald WA, Cripps AW, Pyne DB, Clancy RL, Fricker PA (1995). The effect on immunity of long-term intensive training in elite swimmers. Clin Exp Immunol 102: 210-216.

Gleeson M, Allgrove JE, Reddin D (2007). Salivary cortisol, testosterone and
immunoglobulin A changes during 3 consecutive weeks of training and
International competition in elite rugby union players. Proceedings of the 12th
Annual Congress of the European College of Sport Science, Jyvyskala, July
2007.
Prof Michael Gleeson           January 2008



To discuss any of the above please contact:

europe@salimetrics.com