Cardiac surgeons install tiny temporary pump inside heart

Wednesday, 2 October 2013

Islamabad, Oct 3 (Newswire): Cardiologists weave an eight gram pump through an artery in the groin into the left ventricle, where it pumps up to five liters of blood per minute.

This temporary device assists the heart as it recovers after surgery, prompting faster recovery.

Not only do patients need rest after heart surgery, so do their hearts! Next, a new device that helps weak hearts heal.

J.J. McCarthy is happy to be moved into his new home, but not long ago, breathing problems would have made even unpacking a box difficult. "I started having some shortness of breath and I went in to get it check out," he told Ivanhoe.

McCarthy learned he had a heart problem and needed bypass surgery, but a delicate heart can take a beating during surgery. "We repair a heart in surgery," Bartley Griffith, M.D., a heart surgeon at the University of Maryland Medical Center in Baltimore, told Ivanhoe. "It's a little bit like we create a bruise and the bruise has to heal in the heart."

Now, to help hearts heal after surgery, cardiac surgeons temporarily implant a new device that helps the heart pump blood, giving it a short-term rest. "It basically can perform the function of two-thirds of the heart, and so we let the heart kind of just hang out and repair itself," Dr. Griffith explains.

The tiny pump fits inside a catheter that is inserted through an artery in the groin leading to the heart. The device then helps pump blood in the left ventricle -- the heart's main pumping chamber. It's designed to support the heart for a week or less after surgery, allowing the heart to recover faster. "I think we can pull more patients through open heart surgery than we ever could before, because we have a powerful tool to assist the heart healing," Dr. Griffith says.

McCarthy needed the pump for just two days after surgery. His heart healed quickly and he was back on his feet. "I think it really shortened my recovery time a lot," McCarthy says. "I was able to get up and around a lot faster."

The heart pump device can pump up to five liters of blood per minute -- about three-quarters of a normal heart's output of seven liters per minute. After the device has done its job, it's removed from the patient.

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Cocaine or ecstasy consumption during adolescence increases risk of addiction

Islamabad, Oct 3 (Newswire): Exposure to ecstasy or cocaine during adolescence increases the "reinforcing effects" that make people vulnerable to developing an addiction.

This is the main conclusion of a research team from the University of Valencia (UV), which has shown for the first time how these changes persist into adulthood.

"Although MDMA and cocaine are psychoactive substances frequently used by teenagers, very few studies have been done to analyse the short and long-term consequences of joint exposure to these drugs," says José Miñarro, lead author of the study and coordinator of the Psychobiology of Drug Addiction group at the UV.

The study, published in the journal Addiction Biology, shows for the first time that exposure to these drugs during adolescence leads to long-lasting changes that increase the reinforcing power of ecstasy or MDMA, and which last until adulthood.

Miñarro's team studied the joint consumption of different drugs in order to carry out an in-depth examination into the effects of this interaction. The scientists administered MDMA, cocaine and saline solution to mice over an eight-day period. "The animals exhibited an increase in vulnerability to re-establishing behaviour (relapse), showing a preference for certain environments previously associated with the pleasant effects of the drug," explains Miñarro.

The results highlight that the so-called "reinforcing effects" are greater in adult mice treated with ecstasy or cocaine during adolescence than in adolescent mice not exposed to these drugs. "Adolescence is a critical stage in development, during which time drug consumption affects plastic cerebral processes in ways that cause changes that persist right through to adulthood," adds the scientist.

The results of various surveys, both national and international, show that one of the most common patterns of drug use is polyconsumption. Ecstasy is regularly consumed alongside other drugs such as alcohol, cannabis and cocaine. These same surveys show that 44% of cocaine users in Spain also take ecstasy, and this consumption takes place primarily during adolescence.

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Different genes influence smoking risk during adolescence and adulthood

Islamabad, Oct 3 (Newswire): There is growing evidence that the risk factors for addiction change throughout the lifespan.

The risk factors for developing addiction in adolescence are the most intensively studied because this life phase is associated with the highest addiction risk.

Traits linked to addiction risk during adolescence include pleasure-seeking, behavioral disinhibition, and devaluation of the future negative consequences of behavior. In contrast, the development of substance use among adults is more commonly associated with high levels of stress, anxiety, and depression.

Thus, perhaps it is not surprising that different sets of genes are now implicated in the risk for addiction in adolescence and adulthood.

In a new study published in Biological Psychiatry, researchers found that teenagers carrying variants in two gene regions were three times more likely to become regular smokers in adolescence and twice as likely to be persistent smokers in adulthood, compared to non-carriers.

Variation in a set of dopamine-related genes was associated with a person's risk of starting smoking, and these genes had a stronger impact on smoking initiation in adolescents than in adults. Individuals carrying the risk variants had a 1.3-fold increased risk of starting smoking in their teenage years.

The other set of genes coded for subunits of the nicotinic cholinergic receptors, the brain targets for nicotine inhaled during smoking. Variation in these genes influenced the likelihood of smokers continuing the habit into adulthood, as it had a stronger influence on the smoking habits of adults than of adolescents. Those carrying these variants had a 1.3-fold increased risk of becoming a heavy and persistent smoker in adulthood.

"These findings seem to make some sense. The dopamine-related genes may be more closely associated with the risk for addiction within the context of thrill-seeking, while cholinergic receptors, which have been implicated in mood and cognition as well as addiction, might contribute to self-medication models of addiction," commented Dr. John Krystal, Editor of Biological Psychiatry.

The researchers say the findings could help develop genetic testing for those wishing to know their susceptibility to nicotine dependence and tobacco-related disease. It could also pave the way for targeted drugs that influence an individual's response to nicotine. However, further research is necessary before these goals could be implemented.

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Feast your eyes on the fried egg nebula

Tuesday, 1 October 2013

Islamabad, Oct 2 (Newswire): Astronomers have used ESO's Very Large Telescope to image a colossal star that belongs to one of the rarest classes of stars in the Universe, the yellow hypergiants.

The new picture is the best ever taken of a star in this class and shows for the first time a huge dusty double shell surrounding the central hypergiant. The star and its shells resemble an egg white around a yolky center, leading the astronomers to nickname the object the Fried Egg Nebula.

The monster star, known to astronomers as IRAS 17163-3907 [1], has a diameter about a thousand times bigger than our Sun. At a distance of about 13 000 light-years from Earth, it is the closest yellow hypergiant found to date and new observations show it shines some 500 000 times more brightly than the Sun [2].

"This object was known to glow brightly in the infrared but, surprisingly, nobody had identified it as a yellow hypergiant before," said Eric Lagadec (European Southern Observatory), who led the team that produced the new images.

The observations of the star and the discovery of its surrounding shells were made using the VISIR infrared camera on the VLT. The pictures are the first of this object to clearly show the material around it and reveal two almost perfectly spherical shells.

If the Fried Egg Nebula were placed in the centre of the Solar System Earth would lie deep within the star itself and the planet Jupiter would be orbiting just above its surface. The much larger surrounding nebula would engulf all the planets and dwarf planets and even some of the comets that orbit far beyond the orbit of Neptune. The outer shell has a radius of 10 000 times the distance from Earth to the Sun.

Yellow hypergiants are in an extremely active phase of their evolution, undergoing a series of explosive events -- this star has ejected four times the mass of the Sun in just a few hundred years [3]. The material flung out during these bursts has formed the extensive double shell of the nebula, which is made of dust rich in silicates and mixed with gas.

This activity also shows that the star is likely to soon die an explosive death -- it will be one of the next supernova explosions in our galaxy [4]. Supernovae provide much-needed chemicals to the surrounding interstellar environment and the resulting shock waves can kick start the formation of new stars.

The Very Large Telescope mid-IR instrument, VISIR, captured this delicious image of the Fried Egg Nebula through three mid-infrared filters that are here coloured blue, green and red.
 [1] The name indicates that the object was first spotted as an infrared source by the IRAS satellite in 1983 and the numbers show the star's place in the sky, in the heart of the Milky Way in the constellation of Scorpius (The Scorpion).

[2] IRAS 17163-3907 is one of the 30 brightest stars in the infrared sky, at the wavelength of 12 microns observed by IRAS, but it had been overlooked because it is quite faint in visible light.

[3] The total mass of this star is estimated to be roughly twenty times that of the Sun.

[4] After burning all their hydrogen all stars of ten solar masses or more become red supergiants. This phase ends when the star has finished burning all of its helium. Some of these high-mass stars then spend just a few million years in the post-red supergiant phase as yellow hypergiants, a relatively short time in the life of a star, before rapidly evolving into another unusual type of star called a luminous blue variable. These hot and brilliant stars are continuously varying in brightness and are losing matter due to the strong stellar winds they expel. But this is not the end of the star's evolutionary adventure, as it may next become a different kind of unstable star known as a Wolf-Rayet star, before ending its life as a violent supernova explosion.

[5] The three mid-infrared filters that were used passed light at wavelengths around 8590 nm (coloured blue), 11 850 nm (coloured green) and 12 810 nm (coloured red).

This research is presented in a paper "A double detached shell around a post-Red Supergiant: IRAS 17163-3907, the Fried Egg nebula " by E. Lagadec et al., submitted to the journal Astronomy & Astrophysics.

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