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Tag Archive for ‘American Journal of Physiology’

What do ‘peeps’ and ‘yo-yos’ have to do with diving?

Until now I had assumed that a “peep” was that squishy sugar-covered marshmallow treat that we enjoyed as kids and a “yo-yo” was a toy on a string. As it turns out, peep and yo-yo are also term used to described types of diving patterns. A square dive is one in which there are no excursions to the surface, known as a “peep”, except at the end of the dive, of course. This is in contrast […]

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Drug increases blood flow to the brain – Implications for stroke?

Researchers from Friedrich Schiller University (Jena, Germany) and Heinrich-Heine-University (Düsseldorf, Germany) teamed up to test whether a heart failure medication that is currently being tested might also improve blood flow in the brain. Their findings were published last month in the American Journal of Physiology, Heart and Circulatory Physiology. According to the study authors, the small blood vessels in the brains of sheep closely resemble those in the human brain. Using imaging techniques, they […]

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Ceramides cause rainbow trout to eat less

Ceramides are a type of sphingolipid composed of both fatty acids and sphingosine that are important in maintaining the structure of cell membranes and cell signaling pathways. Given their structure, it is perhaps not surprising that levels of ceramide are increased in the brains of mammals after eating a diet high in fats as well as in individuals who are obese.  In mammals, ceramides are also known to help regulate food intake. Since rainbow trout (Oncorhynchus […]

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How the rectum helps prevent dehydration in saltwater

Teleost fish living in saltwater environments are constantly compensating for water loss. This happens because their surroundings have higher concentrations of salts than their plasma and the rule of thumb in Biology is: water follows salt.  Thus these fish must somehow compensate for water loss in order to prevent dehydration. One way they do this is by drinking a lot of water. Ions are then removed from the water in the intestines which […]

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Keeping arteries healthy, lessons from seals?

Heart rate decreases during diving in seals and other animals. Thus the ascending aorta becomes very important during diving as it helps to maintain blood pressure during prolonged dives. A new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology was designed to examine the ascending aorta of hooded seals (Cystophora cristata) and the tiny blood vessels that supply nutrients to it, called the vasa vasorum. The […]

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Cartilaginous fish need to regulate sulfate too

Seawater contains sulfate concentrations that are nearly 40 times those measured in plasma. Therefore, it is easy to see why fish would need to develop mechanisms to keep sulfate within a physiologically normal range. The kidneys of teleost fish have been known to excrete excess sulfate in the urine. However until now, it was not known whether the kidneys of cartilaginous fish do the same thing as their kidneys are rather complex. In a new […]

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What does nitric oxide have to do with a fever?

New research published in the American Journal of Physiology Regulatory, Integrative and Comparative Physiology shows that bacterial infections increase the production of nitric oxide in chicks, which is similar to what happens in rodents. The increase in nitric oxide is thought to be related to the development of fever. In fact, when nitric oxide production was blocked, thermogenesis was inhibited and infected chicks began to huddle more to increase body temperature. Source: […]

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Heat stress in livestock

With the approach of summer, a timely study was published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology on whether inflammation plays a role in heat stress-related complications in muscles. Heat stress is a major problem in the livestock industry. In the United States alone it is reportedly associated with a loss of approximately $158 billion annually in the swine industry. To cool off, swine seek shade and often mud baths […]

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