Scientists recently discovered surprising evidence that more brown fat (as a result of cold treatment) could increase a person’s risk of getting a stroke or a heart attack. The finding could explain why more people die of cardiovascular diseases during the winter months.
Since February 2013, China experienced an outbreak of the novel H7N9 avian flu, causing 131 cases of infection, and a death toll of 39. This particular H7N9 strain is considered to be one of the most worrisome pathogens since the H5N1 pandemic in 1997; a reputation based on the virus’ ability to spread easily across species and to infect humans. According to the May 23, 2013 Science paper published by the Joint Influenza Research Centre (State Key Laboratory of Emerging Infectious Diseases, Shantou PR, China), Drs. Y. Guan and Y. Shu reported that H7N9 infects the upper respiratory tract of ferrets and pigs, and spreads via direct contact, suggesting that the rapid surge of H7N9 infections are likely caused by human’s direct contact with infected birds.
Female mosquitoes are predators of mammalian blood, relying on blood proteins to lay their eggs. While certain mosquito species are attracted to mammals by their emission of body heat and carbon dioxide, other species, such as Anopheles gambiae and Aedes aegypti, have evolved a strong lust for the smell of humans. Such mosquitoes are also deadly vectors that contribute to the efficient spread of human diseases such as malaria, Dengue hemorrhagic fever, West Nile fever, and chikungunya, with the latter two commonly known as urban epidemics.
The itch sensation is triggered by two categories of itch-inducing agents: histamine (involving the histamine receptor) and non-histamine (involving a Mas-like G-protein coupled receptor). While the molecular distinction is crucial for developing effective treatments for the specific forms of itch sensation, it remains unclear as to how the two forms of itch sensations are encoded in the sensory system. A heavily debated school of thought suggests that itch sensation, in response to either histamine and non-histamine inducers, is differentially triggered by distinct populations of sensory neurons, although such model has never been proven.
The human intestinal tract is the home of a diverse array of bacterial colonies, settling in as soon as their host begins life. While these colonies were considered to merely coexist with the host for their own survival, decades of study have shown the interaction between bacteria and host is mutually beneficial. The bacterial colonies benefit by finding their home in the host, while the host benefits from the bacteria’s ability to keep the intestinal tract healthy, specifically by aiding in the absorption of nutrients, and by preventing disease-causing bacteria from taking root.
Mammals have the ability to adapt to a range of the temperature. While physiological homeostasis has a lot to do with this, part of the reason why mammals can adapt to cold temperatures is the presence of energy-burning brown fat cells. Unlike the large fat storage units in white fat cells (the cell type responsible for obesity), brown fat cells have the capacity to generate heat and provide insulation from cold. Recently, scientists discovered a population of fat cells with the properties of brown and white fat cells, a population dubbed the beige (brite cells) that emerges in mammalian fat as a result of cold adaptation.