Air Quality and Temperature Effects on Exercise‐Induced Bronchoconstriction


ABSTRACT

Exercise‐induced bronchoconstriction (EIB) is exaggerated constriction of the airways usually soon after cessation of exercise. This is most often a response to airway dehydration in the presence of airway inflammation in a person with a responsive bronchial smooth muscle. Severity is related to water content of inspired air and level of ventilation achieved and sustained. Repetitive hyperpnea of dry air during training is associated with airway inflammatory changes and remodeling. A response during exercise that is related to pollution or allergen is considered EIB. Ozone and particulate matter are the most widespread pollutants of concern for the exercising population; chronic exposure can lead to new‐onset asthma and EIB. Freshly generated emissions particulate matter less than 100 nm is most harmful. Evidence for acute and long‐term effects from exercise while inhaling high levels of ozone and/or particulate matter exists. Much evidence supports a relationship between development of airway disorders and exercise in the chlorinated pool. Swimmers typically do not respond in the pool; however, a large percentage responds to a dry air exercise challenge. Studies support oxidative stress mediated pathology for pollutants and a more severe acute response occurs in the asthmatic. Winter sport athletes and swimmers have a higher prevalence of EIB, asthma and airway remodeling than other athletes and the general population. Because of fossil fuel powered ice resurfacers in ice rinks, ice rink athletes have shown high rates of EIB and asthma. For the athlete training in the urban environment, training during low traffic hours and in low traffic areas is suggested.

Neuroscientists discover that cold is contagious


Just looking at someone else shiver from the cold can cause certain parts of our bodies to drop in temperature, scientists have discovered, providing the first evidence for a phenomenon known as ‘temperature contagion’.

Hot day? Cool yourself down by watching a video about someone being cold, researchers are saying, thanks to a new study that shows the feeling of being cold is contagious, whereas the feeling of hot is not.

A team of neuroscientists led by Ella Cooper from the University of Sussex and John Garlick from University College London, both in the UK, gathered together 36 volunteers who watched eight different three-minute videos that depicted actors with either their right or left hands in visibly warm or cold water, or their hands in front of the water as a control component. No emotional cues were given by the actors to show pain or discomfort.

Before and after each video was watched, the temperatures of the volunteers’ right and left hands were measured and compared to see if any change had occurred. The temperature in the room was managed and the volunteers were asked to keep their hands as still as possible to minimise changes in temperature due to muscle movement. Even the tiny amount of heat that comes off a television screen was accounted for.

 

“While watching the warm and neutral videos did not produce any changes in subjects’ hand temperature, watching the cold videos caused a small, but unmistakable drop,” says Ross Pomeroy at Real Clear Science. “The temperature of subjects’ right hands fell by an average of 0.1 degrees Fahrenheit, and the temperature of their left hands fell [by] 0.4 degrees. There was no change in heart rate.”

So we’re talking about the tiniest fraction of a degree Celsius – barely anything, but it’s still something, just from watching a video, and that’s fascinating.

Publishing their results in the journal PLoS ONE, the team suggest that the reason the warm videos didn’t provoke a physiological response in the volunteers while the cold videos did could be because while the steam coming off the warm water indicated that it was warm, perhaps it wasn’t as visible to the volunteers as the ice cubes floating around in the water of the cold videos. That, and the fact that previous research “has highlighted that temperature decreases are typically easier to elicit and of greater magnitude than temperature increases,” they report.

Interestingly, the team got the volunteers to self-report their levels of empathy, and these measurements actually predicted their differences in sensitivity to the temperature contagion.

This means the researchers can add a new physical condition to the phenomenon of emotional contagion – the tendency for two individual people to mimic each other’s expressions and emotional states, the researchers concluded. They explain further in the paper:

“Emotional contagion is thought to be mediated by mirror neurons, brain cells that fire both when an animal performs a certain action or observes that action. The study also broadly substantiates an extreme case of human temperature fluctuation documented in 1920 by scientist J.A. Hadfield, who worked with a patient who was able to selectively adjust their right and left hand temperature by as much as 5 degrees Fahrenheit through suggestions of heat or cold.

 

Breath temperature test helps diagnose lung cancer


The temperature of a person’s exhaled breath may be a simple, non-invasive diagnostic test for non-small cell lung cancer (NSCLC), according to a study, the results of which were presented at the recent European Respiratory Society (ERS) International Congress held in Munich, Germany.

“The results of our study showed that the exhaled breath temperature is increased in non-small cell lung cancer patients,” said lead study author Professor Giovanna Elisiana Carpagnano from the University of Foggia in Italy. “[They] suggest that lung cancer causes an increase in the exhaled temperature. This is a significant finding and could change the way we currently diagnose the disease. If we are able to refine a test to diagnose lung cancer by measuring breath temperature, we will improve the diagnostic process by providing patients with a stress-free and simple text that is also cheaper and less intensive for clinicians.”

Of 82 patients with radiological evidence of NSCLC enrolled in the study, 40 patients tested positive for the disease, while 42 patients had the diagnosis rejected. Using a breath thermometer device known as the X-Halo device, the researchers found that the patients with NSCLC had significantly elevated exhaled breath temperature (EBT) compared with those without (35.4°C vs 33.4°C; p<0.001). [Abstract P1928]

“And when we stratified for sex, age, [cigarette smoking] habit and COPD, these values remained higher in the cases [compared with] the controls,” said Carpagnano. “Among the non-small cell lung cancer patients we didn’t find any differences for histological type… We observed the higher temperatures in the more advanced stages.”

Carpagnano added that the researchers performed an analysis to determine a cut-off EBT value that could identify NSCLC with a high level of accuracy. Their analysis revealed that 96 percent of patients with an EBT >34°C had NSCLC. “This cut-off value of 34°C may be accompanied by a lung cancer diagnosis,” she suggested.

Normal EBT is in the range of 29 to 30°C. Elevated EBT has long been shown to indicate the presence of airways inflammation and scientists in the early 20th century were using it to assess patients with asthma. Carpagnano suggested that this knowledge, together with recent evidence demonstrating that airways inflammation and neoangiogenesis play a key role in the pathogenesis of lung cancer, gives important impetus to the research conducted by her team.
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Targeted Temperature Management at 33°C versus 36°C after Cardiac Arrest.


BACKGROUND

Unconscious survivors of out-of-hospital cardiac arrest have a high risk of death or poor neurologic function. Therapeutic hypothermia is recommended by international guidelines, but the supporting evidence is limited, and the target temperature associated with the best outcome is unknown. Our objective was to compare two target temperatures, both intended to prevent fever.

METHODS

In an international trial, we randomly assigned 950 unconscious adults after out-of-hospital cardiac arrest of presumed cardiac cause to targeted temperature management at either 33°C or 36°C. The primary outcome was all-cause mortality through the end of the trial. Secondary outcomes included a composite of poor neurologic function or death at 180 days, as evaluated with the Cerebral Performance Category (CPC) scale and the modified Rankin scale.

RESULTS

In total, 939 patients were included in the primary analysis. At the end of the trial, 50% of the patients in the 33°C group (235 of 473 patients) had died, as compared with 48% of the patients in the 36°C group (225 of 466 patients) (hazard ratio with a temperature of 33°C, 1.06; 95% confidence interval [CI], 0.89 to 1.28; P=0.51). At the 180-day follow-up, 54% of the patients in the 33°C group had died or had poor neurologic function according to the CPC, as compared with 52% of patients in the 36°C group (risk ratio, 1.02; 95% CI, 0.88 to 1.16; P=0.78). In the analysis using the modified Rankin scale, the comparable rate was 52% in both groups (risk ratio, 1.01; 95% CI, 0.89 to 1.14; P=0.87). The results of analyses adjusted for known prognostic factors were similar.

CONCLUSIONS

In unconscious survivors of out-of-hospital cardiac arrest of presumed cardiac cause, hypothermia at a targeted temperature of 33°C did not confer a benefit as compared with a targeted temperature of 36°C.

Source: NEJM

 

Active Versus Passive Cooling During Neonatal Transport.


BACKGROUND AND OBJECTIVE: Therapeutic hypothermia is now the standard of care for hypoxic-ischemic encephalopathy. Treatment should be started early, and it is often necessary to transfer the infant to a regional NICU for ongoing care. There are no large studies reporting outcomes from infants cooled passively compared with active (servo-controlled) cooling during transfer. Our goal was to review data from a regional transport service, comparing both methods of cooling.

METHODS: This was a retrospective observational study of 143 infants referred to a regional NICU for ongoing therapeutic hypothermia. Of the 134 infants transferred, the first 64 were cooled passively, and 70 were subsequently cooled after purchase of a servo-controlled mattress. Key outcome measures were time to arrival at the regional unit, temperature at referral and arrival at the regional unit, and temperature stability during transfer.

RESULTS: The age cooling was started was significantly shorter in the actively cooled group (46 [0–352] minutes vs 120 [0–502] minutes; P <.01). The median (range) stabilization time (153 [60–385] minutes vs 133 [45–505] minutes; P = .04) and age at arrival at the regional unit (504 [191–924] minutes vs 452 [225–1265]) minutes; P = .01) were significantly shorter in the actively cooled group. Only 39% of infants passively cooled were within the target temperature range at arrival to the regional unit compared with 100% actively cooled.

CONCLUSIONS: Servo-controlled active cooling has been shown to improve temperature stability and is associated with a reduction in transfer time.

Source: http://pediatrics.aappublications.org

Smartphones could provide weather data in poor nations.


Smartphones can now be used to collect weatherdata such as air temperatures through WeatherSignal, a crowdsourcing app developed by UK start-up OpenSignal.

This helps crowdsource real-time weather forecasts and could one day help collect climate data in areas without weather stations, its developers say.

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Once installed, the app automatically collects data and periodically uploads them to a server.

The app’s ability to record air temperature is based upon the discovery that the temperature of a smartphone battery correlates closely to the surrounding air temperature, published in Geophysical Research Letters this month (13 August).

Lithium ion batteries have temperature sensors to prevent damage caused by attempts to charge them when the battery is too hot,” the paper says.

But these sensors do not provide a direct air temperature measurement — due to heat being emitted by both the smartphone and its user. So the researchers used a model that estimates the outside temperature based on smartphone readings.

The fact that battery temperature correlates with ambient air temperature was discovered by accident, James Robinson, one of the authors of the paper and co-founder of OpenSignal, tells SciDev.Net.

“When data from many phones are joined together, they become even more powerful and will allow us to make weather predictions of unprecedented detail.”

James Robinson

The team was researching energy consumption in relation to poor mobile network signal, a condition that is known to reduce battery performance.

“We started playing with the data and decided to look at average battery temperature versus historic weather temperature, and we found a really strong correlation,” says Robinson.

The data came from eight major cities around the world covering a wide range of climate zones, and including Buenos Aires, Mexico City and São Paulo.

“Many smartphones have a variety of sensors,” says Robinson. “When data from many phones are joined together, they become even more powerful and will allow us to make weather predictions of unprecedented detail.

Developing countries often invest fewer resources in collecting weather data.

“As smartphones become more popular in developing countries, WeatherSignal could provide a valuable source of weather data — either supplementing existing sources or as the only source for some places,” he says.

“We’re open to working with as many people as possible,” Robinson says. “For instance, we plan on making historic data available to academics and organisations such as the World Meteorological Organization.”

Enzo Campetella, an Argentina-based meteorologist and WeatherSignal user, tells SciDev.Net that although the app has potential, “there are still several stages to accomplish” before it is completely reliable for use in meteorology.

“In meteorology, it is essential that data are comparable, so it is essential that they are collected following the same rules or standards,” he says.

And, in countries where weather stations are scarce, “the possibility of comparing data is much lower”, he explains.

The WeatherSignal team admit that “many additional high-quality urban observations [are] needed to refine the air temperature estimates from smartphones and to expand their possibilities”.

Having more data is also crucial, so they are also working to get as many people as possible using the app.

Source: http://www.scidev.net

Nanodiamond thermometer can find the temperature inside a single living cell.


The mercury-in-glass thermometer has served us well for the past 270 years, but sometimes you need something smaller — say to find the temperature inside a single living cell. Researchers at Harvard have discovered a new technique using lasers and diamond nanocrystals to measure temperatures of microscopic structures, recording temperature fluctuations as small as 0.05 Kelvin (0.09ºF) in size.

The technique relies on the quantum properties of the diamonds’ tasty centers. In a diamond crystals with a nitrogen vacancy in its center — a kind of defect — the center’s electronic spin comes to depend on its temperature. Laser light bouncing out of one of these nanodiamonds shows up as a different color depending on the center’s temperature. And using diamonds also adds some other benefits. Because they’re highly chemically inert, changes in the surrounding chemistry don’t affect the outcome, and the method can be used over a broad range of temperatures, for the same reason. In one series of experiments (pictured above), the team implanted a human cell with a gold nanoparticle, used a laser to heat it up (thereby heating up the surrounding cell), and bounced a laser off a diamond implanted in the same cell to record the temperature difference. The results will be published in the August issue of Nature.

So why would you want to know the temperature inside a living cell? The team believes that the gold heating trick, precisely monitored with its diamond-and-laser nanothermometer, could make it possible to “engineer biological processes at the subcellular level,” possibly helping to screen for cancer, or cooking the perfect steak, one cell at a time.

Source: http://www.theverge.com