The treatment that has been tested is carbonic anhydrase (CA) inhibition, CA being an enzyme that serves to maintain a balance between carbonic acid and carbon dioxide in the body. Several drugs with CA inhibitory properties are already available on the market, and used for treatment of glaucoma, epilepsy and other disorders.

Previous research has not systematically tested whether CA inhibitors also might be used to treat obstructive sleep apnea. The current study was a randomized double-blind clinical trial, and 59 patients with moderate or severe sleep apnea completed it. Patients were randomly assigned to two groups receiving either 400 or 200 mg of the CA inhibitor, and a third group (the control group) that received placebo. The study lasted for four weeks.

Fewer breathing pauses

The results show that, overall, the treatment reduced the number of breathing pauses and promoted oxygenation during the night. A few patients experienced side effects, such as headache and breathlessness, which were more common in those receiving the highest dose.

The study results together with established safety data of the drug sulthiame provide support for continued research on CA inhibition as a new potential treatment for obstructive sleep apnea.

“Among the patients who received the higher dosage of the drug, the number of breathing pauses decreased by approximately 20 per hour. For just over a third of patients in the study, only half of their breathing pauses were left, and in one in five the number fell by at least 60 percent,” says Jan Hedner, Professor of Pulmonary Medicine.

The fact that several approved drugs in the CA inhibitor category are available on the market makes fast-tracking development of an approved drug for sleep apnea practicable. The drug used in this clinical trial was sulthiame, which is sometimes used to treat epilepsy in children.

Treatment options needed

Today, treatment for a patient with sleep apnea is either an oral appliance therapy or a CPAP (Continuous Positive Airway Pressure) mask. Both help to maintain airway patency during sleep.

“These therapy options take time to get used to and, since they frequently are perceived as intrusive or bulky. Insufficient user time is therefore common. If we develop an effective drug, it will therefore make life easier for many patients and, in the long run, potentially also save more lives,” says Ludger Grote, Senior Lecturer at Sahlgrenska Academy, University of Gothenburg.

The German pharmaceutical company Desitin Arzneimittel GmbH funded the trial, and the results are published in the American Journal of Respiratory and Critical Care Medicine.

Story Source:

Materials provided by University of Gothenburg. Note: Content may be edited for style and length.

Liquid droplets and very fine particles can trap light — similar to how light can be caught between two mirrors. As a result, the intensity of the light inside them is amplified. This also happens in very fine water droplets and solid particles in our atmosphere, i.e. aerosols. Using modern X-ray microscopy, chemists at ETH Zurich and the Paul Scherrer Institute (PSI) have now investigated how light amplification affects photochemical processes that take place in the aerosols. They were able to demonstrate that light amplification causes these chemical processes to be two to three times faster on average than they would be without this effect.

Using the Swiss Light Source at the PSI, the researchers studied aerosols consisting of tiny particles of iron(III) citrate. Exposure to light reduces this compound to iron(II) citrate. X-ray microscopy makes it possible to distinguish areas within the aerosol particles composed of iron(III) citrate from those made up of iron(II) citrate down to a precision of 25 nanometres. In this way, the scientists were able to observe and map in high resolution the temporal sequence of this photochemical reaction in individual aerosol particles.

Decay upon exposure to light

“For us, iron(III) citrate was a representative compound that was easy to study with our method,” says Pablo Corral Arroyo, a postdoc in the group headed by ETH Professor Ruth Signorell and a lead author of the study. Iron(III) citrate stands in for a whole range of other chemical compounds that can occur in the aerosols of the atmosphere. Many organic and inorganic compounds are light-sensitive, and when exposed to light, they can break down into smaller molecules, which can be gaseous and therefore escape. “The aerosol particles lose mass in this way, changing their properties,” Signorell explains. Among other things, they scatter sunlight differently, which affects weather and climate phenomena. In addition, their characteristics as condensation nuclei in cloud formation change.

As such, the results also have an effect on climate research. “Current computer models of global atmospheric chemistry don’t yet take this light amplification effect into account,” ETH Professor Signorell says. The researchers suggest incorporating the effect into these models in future.

Non-uniform reaction times in the particles

Now precisely mapped and quantified, the light amplification in the particles comes about through resonance effects. The light intensity is greatest on the side of the particle opposite the one the light is shining on. “In this hotspot, photochemical reactions are up to ten times faster than they would be without the resonance effect,” says Corral Arroyo. Averaged over the entire particle, this gives an acceleration by the above-mentioned factor of two to three. Photochemical reactions in the atmosphere usually last several hours or even days.

Using the data from their experiment, the researchers were able to create a computer model to estimate the effect on a range of other photochemical reactions of typical aerosols in the atmosphere. It turned out that the effect does not pertain just to iron(III) citrate particles, but all aerosols — particles or droplets — made of compounds that can react with light. And these reactions are also two to three times faster on average.

Story Source:

Materials provided by ETH Zurich. Original written by Fabio Bergamin. Note: Content may be edited for style and length.

The study, published in the Journal of Occupational Health Psychology recently, also found that working on a day when you feel ill drains mental energy which cannot be recovered the next day.

The study seeks to shed further light on the phenomenon of ‘presenteeism’ — defined by the researchers as continuing to work when experiencing ill-health. The practice has been labelled an ‘800-pound gorilla’ by researchers in occupational health psychology because of the tremendous costs it inflicts on employees and organisations alike. These costs include burnout, impaired workability, and productivity loss.

This study led by Dr Wladislaw Rivkin, Associate Professor in Organisational Behaviour, Trinity, deepens our understanding of the harmful impact of presenteeism on employee effectiveness by demonstrating that depletion of mental resources is a key mechanism responsible for these harmful effects.

The research involved 126 employees logging their daily productivity across 12 workdays, resulting in 995 daily work observations. It was conducted during the COVID-19 lockdown in 2020 when all participants were working from home.

Dr Rivkin commented:

“It is crucial to tackle daily presenteeism, especially for remote workers. Managers should openly discourage presenteeism by reassuring team members that if they feel unwell it is acceptable to reduce their daily work goals and instead tend to their health. In light of the energy-depleting nature of presenteeism if employees engage in presenteeism they should work on tasks that are inherently pleasant rather than tedious tasks that further drain their energy.

“So, while it may seem a good idea to work despite ill health to deliver on work goals our research shows that this has a knock-on effect for remote workers’ performance on the next day as presenteeism drains employees’ psychological energy, which cannot be fully recovered after work.”

The full paper was entitled “Should I stay or should I go? The role of daily presenteeism as an adaptive response to perform at work despite somatic complaints for employee effectiveness.”

Wlad Rivkin is an Associate Professor in Organisational Behaviour and Work Psychology whose research focuses on burnout, stress and other demands that people experience at work as well as what organisations can do to protect employee wellbeing and maintain their effectiveness. Other recent research projects include studies on the impact of commuting on employee wellbeing, the role of willpower in overcoming the negative effects of a bad night’s sleep and how smartphone use during non-work time impacts on sleep quality.

Story Source:

Materials provided by Trinity College Dublin. Note: Content may be edited for style and length.