Life Lines by Dr. Dolittle

Sponsored by the American Physiological Society

Early indicator of pregnancy complications

Mitochondria are organelles inside our cells that are essential for generating metabolic energy in the form of ATP. It is thought that these organelles originally came from aerobic bacteria that were ingested by the first eukaryotic cells. In fact, mitochondria have their very own DNA. Cells that have higher energy needs, like those in the brain and heart, contain more mitochondria.      When cells die, mitochondrial DNA can end up […]

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What happens in a forest doesn’t always stay in the forest…

So, a male scarlet tanager flies into a forest where he meets an irresistible rose-breasted grosbeak. They share some tasty insects, and the rest is history. Or is it? What happens in a forest, doesn’t always stay in a forest. In fact, this encounter resulted in a hybrid: This male bird, found in Pennsylvania, is the hybrid offspring of a male scarlet tanager (Piranga olivacea) and a female rose-breasted grosbeak […]

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New study discovers how zebrafish mend a broken heart

A new study has helped unravel the mystery explaining how zebrafish regenerate a broken heart. Their findings, published in Nature Genetics, reveal how these amazing little fish can regrow up to 20% of their heart in only 2 months following an injury. This regeneration is driven by signals released from special cells called fibroblasts. When the heart of zebrafish is injured by a stimulus that mimics a heart attack (using […]

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Causes and consequences of stiff arteries

In a new review article published in Physiology, researchers speculate that arterial stiffness in middle-aged adults may actually be the body’s way of trying to compensate for widening of the blood vessel walls as we age. But that benefit turns into a risk with aging as it increases the flow of blood into organs like the brain, kidney, and heart and damages the small blood vessels in those organs. Interestingly, […]

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Heat may activate muscle growth and prevent atrophy

Skeletal muscle is not only important for our ability to move, it also plays a major role in metabolism. Under normal conditions, the routine processes of muscle growth (hypertrophy) and breakdown (atrophy) are in balance. While many of us are aware that exercise and healthy diets promote muscle growth, diseases and sedentary lifestyles can promote muscle atrophy. Studies examining the effects of heat on muscle – from environmental heat, direct […]

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Chronic stress during pregnancy increases risk of stillbirth and preterm delivery

At the end of pregnancy, levels of the hormone oxytocin increase to stimulate parturition, or childbirth. The stress hormone cortisol is also important for normal fetal development and, like oxytocin, cortisol increases at the end of pregnancy. This may help explain why chronic stress during pregnancy increases the risk of complications such as stillbirth.   A new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative […]

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Domestic zebrafish are less plastic

Zebrafish have been used in medical research since at least the 1970’s as their anatomy, physiology, as well as genetics are similar to humans. Other advantages to studying zebrafish is that they are inexpensive to raise, and they reproduce well in captivity. The ability to adjust one’s physiology in response to varying environments is called plasticity. An organism may encounter any number of environmental fluctuations (light/dark, temperatures, predation risk, noise, […]

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Are declines in food availability to blame for the menu change?

Yesterday, we marveled over the recent sightings of two killer whales targeting sharks off the coast of South Africa. The recent uptick in shark hunting has scientists wondering how the loss of great white sharks will impact the ecosystem. But it also has some wondering why the orcas are targeting so many sharks when their diets typically consist of a variety of fish and marine mammals.   Clues may lie […]

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Killer whales scare off sharks

A pair of killer whales, nicknamed ‘Port and Starboard’, has been terrorizing great white sharks. In recent years as many as 8 sharks (possibly more) have succumbed to the pair. Many of the discovered sharks were missing their fatty liver and sometimes their heart. While orca hunting escapades are not particularly newsworthy, the antics of these orcas have attracted the attention of scientists as they are altering the ecosystem. Once […]

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