Life Lines by Dr. Dolittle

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Diet and Exercise

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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Physiology 2016

I am very excited to report that the American Physiological Society in partnership with The Physiological Society held a joint meeting from July 29-31 in Dublin, Ireland. The keynote lectures were given by Dr. Jerry Friedman from Rockefeller University and Dr. W Jon Lederer from the University of Maryland.   Dr. Friedman spoke about his research on obesity and how genetic factors might play a role. In fact, his team was […]

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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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Male hamsters pack on the pounds while females stockpile food for winter

During hibernation common hamsters (Cricetus cricetus) alternate their time between bouts of torpor during which their metabolic rate drops and body temperature is low and arousal during which body temperature is normal. Hibernation allows animals to conserve energy although it is not without costs as it often results in memory deficits, cell damage and reduced immune function. Thus some studies have suggested that animals with sufficient food stores will not undergo hibernation […]

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Muscle Aging in American Quarter horses

Skeletal muscle function and structure change as we age. Humans typically experience a loss of muscle mass or muscle weakness which can greatly reduce mobility and stability. While much is known about aging skeletal muscle in humans and rodents, less is known about horses, which are rather athletic animals that are living longer due to advancements in veterinary care and retirement programs. Researchers from the University of Florida decided to explore how aging effects skeletal […]

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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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Recap of 2016 Michigan Physiological Society

The Michigan Physiological Society, a chapter of the American Physiological Society, held their 3rd annual meeting last week. As mentioned in a prior post, the keynote address was given by Comparative Physiologist Dr. Hannah Carey (University of Wisconsin School of Veterinary Medicine). You can read about her research in the prior post. Here are other highlights from the meeting: Seminars: or as I prefer to view them… Kelsy Kusch (Undergraduate Student, […]

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2016 Michigan Physiological Society Meeting

I am very excited about the upcoming 3rd annual Michigan Physiological Society Meeting on May 12-13 in Detroit. This society is a local chapter of the American Physiological Society. I am most excited by their choice of a Comparative Physiologist for the keynote address: Dr. Hannah V. Carey from the University of Wisconsin School of Veterinary Medicine. Dr. Carey is a Past-President of the American Physiological Society. She will be presenting […]

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Experimental Biology – Day 5

Today was the final day of the meeting. Dr. Joe Thompson (Franklin and Marshall College) spoke about oblique striated muscles, which get their name from the diagonal pattern formed by the location of the Z-lines. This type of muscle is common among cephalopods, nematodes, tunicates, molluscs, etc. Dr. John Whiteman (University of Wyoming) gave a fascinating talk about polar bears and whether hunting on the shore as compared to the sea […]

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Experimental Biology – Day 3

I LOVE THIS MEETING! DAY 3 included several very interesting comparative physiology sessions. Eldon Braun (University of Arizona) spoke about how birds have a unique way to prevent water loss and thereby dehydration. In mammals, the kidneys are responsible for recovering water from the urine. However when birds are well-hydrated, the urine enters the colon and moves backwards up the gastrointestinal tract to facilitate water reabsorption prior to voiding the […]

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