Raising ‘good’ cholesterol levels reduces heart attack and stroke risk in diabetes patients

 by Biomechanism

“Kaiser Permanente study also finds heart attack and stroke risk increase when ‘good’ cholesterol levels go down”

Increasing levels of high-density lipoproteins, better known as HDL or “good” cholesterol, reduced the risk for heart attack and stroke among patients with diabetes. That’s according to a new study appearing online today in The American Journal of Cardiology.

The observational study, one of the largest of its kind, examined the medical records of more than 30,000 patients with diabetes and also found that patients whose HDL levels decreased had more heart attacks and strokes.

Researchers studied patients with diabetes because they are more prone to heart disease with a lifetime risk as high as 87 percent, according to a paper from the landmark Framingham heart study published 2008. While there is considerable evidence that reducing the amount of low-density lipoprotein, also known as LDL or “bad” cholesterol, can reduce the risk of heart disease, the relationship between HDL cholesterol and heart disease is less clear.

“Our study adds to the growing body of evidence that raising HDL levels may be an important strategy for reducing heart attack risk,” said study lead author Gregory Nichols, PhD, senior investigator with the Kaiser Permanente Center for Health Research in Portland, Ore.

“This is promising news for patients with diabetes, who already have an increased risk for heart problems. Raising their good cholesterol may be one more way for these patients to reduce their risk,” said Suma Vupputuri, PhD, co-author and investigator with the Kaiser Permanente Center for Health Research in Atlanta.

The study included 30,067 patients who entered Kaiser Permanente diabetes registries in Oregon, Washington and Georgia between 2001 and 2006. These patients had at least two HDL cholesterol measurements between 6 and 24 months apart. Most patients (61 percent) had no significant change in HDL levels; in 22 percent of patients, HDL levels increased by at least 6.5 mg/dl (milligrams per deciliter of blood); in 17 percent of patients, HDL levels decreased by at least that same amount.

After obtaining the cholesterol measurement, researchers followed the patients for up to 8 years to see if they were hospitalized for a heart attack or stroke. Patients whose HDL levels increased had 8 percent fewer heart attacks and strokes than patients whose HDL levels remained the same, while patients whose HDL levels decreased had 11 percent more heart attacks and strokes. This study was observational so there was no intervention to change HDL levels, and although many patients were on statins to reduce their “bad” cholesterol, very few were on medications to improve HDL.

Past studies on this topic have reached contradictory conclusions. A study published in 2009 in the Archives of Internal Medicine found that for every 5 mg/dl improvement in HDL cholesterol level patients saw a 21 percent decrease in heart attack risk. But a systematic review of more than 100 clinical trials published in the British Medical Journal in 2009 found that increasing HDL cholesterol did not reduce the risk of heart disease or death.

Earlier this year the National Institutes of Health stopped a clinical trial using large doses of the B Vitamin niacin to boost HDL levels because the patients, who were already taking statins to reduce their “bad” cholesterol, saw no added reduction in heart attacks when they added niacin. Niacin is one of very few medications to increase HDL, but it can also have side effects such as flushing, vomiting, dizziness and itching.

People can raise their HDL levels without medication by keeping their weight down, changing their diet, avoiding tobacco smoke, and increasing exercise.

Medical experts believe that HDL or “good” cholesterol carries the “bad” cholesterol away from the arteries and back to the liver where it is processed and passed from the body. According to the American Diabetes Association, a good target for women should be at least 50 mg/dl of HDL and for men at least 40 mg/dl. Levels of 60 mg/dl or higher are thought to protect against heart disease

Fish jump into picture of evolutionary land invasion

 by Biomechanism 

Research sometimes means looking for one thing and finding another. Such was the case when biology professor Alice Gibb and her research team at Northern Arizona University witnessed a small amphibious fish, the mangrove rivulus, jump with apparent skill and purpose out of a small net and back into the water.

This was no random flop, like you might see from a trout that’s just been landed. The rivulus seemed to know what it was doing.

The time-elapsed image above, taken by researchers at Northern Arizona University, shows the mosquitofish's ability to move outside of water with apparent skill and purpose. The study suggests that vertebrates may have invaded land more frequently than previously thought. Photo: NAU

They hadn’t expected to see that behavior, even from a fish known to spend time out of the water. So before long, what began as a study on the evolution of feeding behavior was shifted to a study of how fish behave when stranded on land. And considering what is implied by the truism “like a fish out of water,” the results came as another surprise.

Some fully aquatic fishes, as the author’s video clipsshow, also can jump effectively on land even without specialized anatomical attributes. This has significant implications for evolutionary biology, Gibb said, because the finding implies that “the invasion of the land by vertebrates may have occurred much more frequently than has been previously thought.”

The study is summarized in a paper, “Like a Fish out of Water: Terrestrial Jumping by Fully Aquatic Fishes,” that appears online in the JEZ A: Ecological Genetics and Physiology.

Gibb said the study “supports a big-picture theory in evolution,” which is that the nervous system, in its control of bones and muscles, can allow a new behavior to appear without necessarily bringing about a physical change.

In the case of aquatic fish, Gibb said, “This shows that you don’t have to have legs or rigid pectoral fins to move around on land. So if you go back and look at the fossil record to try to say which fish could move around on land, you’d have a hard time knowing for sure.”

The original feeding study began with guppies, then moved to a relative, the mangrove rivulus. Once the rivulus exhibited the tail-flip jumping maneuver, Gibb shifted the focus of the research. Eventually, the guppy came back into the picture. Literally.

“When you do a study like this, you have to ask what your control is,” Gibb said. “If a known amphibious fish is a good jumper, then what’s a bad jumper?”

Enter the guppy, a fully aquatic fish 

“The guppy jumped almost as well as the amphibious fish did,” Gibb said. “And no one has ever suggested that a guppy is an amphibious fish.” As a result, “we put everything we could get our hands on” in front of a high-speed camera, Gibb said. Some of those additional subjects included the mosquitofish, which has been introduced into tributaries of Oak Creek, and a common pet store zebra fish, which is a very distant relative of guppies and mosquitofish.

The mosquitofish “has become our lab rat,” Gibb said. “It’s accessible, it comes from a group that has other jumpers, and it’s been reported that this fish jumps out of the water to get away from predators and then jumps back in.”

That particular escape behavior, Gibb said, has never been filmed. Similar stories about other fish add to mostly anecdotal literature on the topic that “tends to be old and very diffuse.”

Today’s high-speed video systems give Gibb an opportunity to change that. What the cameras reveal is that both species produce a coordinated maneuver in which the fish curls its head toward the tail and then pushes off the ground to propel itself through the air.

Gibb and her team have discussed going into the field to capture video of fish performing this behavior in the wild. But for now Gibb and her colleagues are endeavoring to determine if there is directionality to voluntary locomotion on land and to investigate the genetic basis of the jumping behavior.

“Maybe fishes that are very good at jumping are poor swimmers,” Gibb said. “We want to look at the compromises that may have been made to favor one behavior over another.”

பாம்பு தலையுடன் கூடிய பிரமீடு கண்டுபிடிப்பு

மெக்சிகோ நகரின் புகழ்பெற்ற அரச சிதைவுகளில் பாம்புகளை எரிப்பதற்காக உருவாக்கப்பட்ட சிறப்பு மேடை கண்டுபிடிக்கப்பட்டுள்ளது. மெக்சிகோ நகரின் Templo Mayo சிதைவுகளிலேயே அகழ்வாராய்ச்சியாளர்கள் இதனை கண்டுபிடித்துள்ளனர். இரு பிரமீடுகளுக்கிடையிலும் பல ஆன்மீகம் தொடர்பான Hispanic Aztec இராச்சியத்தின் முக்கிய இடமாகவும் இருந்த இடத்தில் இந்த பாம்புத் தலைகளிலான சிலை வடிவமைக்கப்பட்டிருந்தது. பாம்பின் தலை வடிவத்தில் அமைந்த அமைப்பு புதிதாகக் கண்டுபிடிக்கப்பட்டுள்ளது. அப்பகுதியில் ஏதாவது அரச பரம்பரையினரின் புதைகுழி இருக்கலாமென 5 ஆண்டுகளாகத் தேடிவந்திருந்தனர். ஆனால் அப்படியான எந்தவிதப் புதைகுழியும் அங்கு கண்டுபிடிக்கப்படவில்லை. இப்பகுதி 15 யார் விட்டத்தில் காணப்பட்டதுடன் கி.மு. 1469 இலும் கட்டப்பட்டிருந்தது என ஆய்வாளர்கள் தெரிவித்துள்ளார்கள். இப்பகுதி மெக்சிகோவின் Teochtitlan என்ற நகரின் தலைநகரான Aztec பகுதியில் அமைந்திருந்தது. இங்குதான் ஆட்சியாளர்கள் எரிக்கப்பட்டார்கள் என வரலாற்றுப் பதிவுகள் கூறுகின்றன. அப்பகுதிதான் தற்போது கண்டுபிடிக்கப்பட்ட இடமாக இருக்கலாமென அகழ்வாராய்ச்சியாளர்கள் கருதுகின்றனர். இந்தப் பிரமீடு பகுதியில் தான் அக்காலத்து மதகுருமார்கள் பாம்புடன் இறங்கி, அந்தப் பாம்பு மேடையில் வைத்து எரித்திருக்கலாம் என இவர்கள் நம்புகின்றார்கள். இங்கு 19 பாம்பின் தலைகள் மேடைகளாக வரிசையாகக் கட்டப்பட்டுள்ளன. இப்பகுதி 2006 இல் கண்டுபிடிக்கப்பட்டிருந்தாலும் தற்போதுதான் முழுதாக இந்த பாம்பு மேடைகள் கண்டுபிடிக்கப்பட்டுள்ளன.