33 posts · 16,803 views
Stem cells have two key characteristics. They are able to self-renew and they can differentiate into mature cells of different lineages. These two properties allow stem cells to repair and regenerate tissues and organs. Stem cells also form the corner-stone of tissue engineering. The underlying biological mechanisms that regulate stem cell function and self-renewal are fairly complex and our knowledge of remains very limited.The field of stem cell research has generated a lot of enthusiasm, but this enthusiasm can at times skew the interpretation of the actual scientific findings. I believe that the hope of being able to regenerate or rejuvenate tissues taps into the old human quest for immortality. This may be the reason why I often come across reports and discussions suggesting that stem cell therapies have a miracle-like quality and will soon be able to cure most diseases. While the ground-breaking discoveries in stem cell biology are indeed fascinating, it is also important to have a realistic view of stem cell therapies and realize that much of stem cell biology is still in its infancy. Premature attempts to use stem cells for clinical therapies are probably not going to succeed. This blog will focus on novel developments in stem cell research, regenerative biology and medicine as well as the topic of aging. The ethical and political issues that revolve around stem cell research will also be discussed. I am also interested in broader questions related to the process of scientific discovery, creativity and scientific communication, which will be addressed in some of the posts.
When you get an infection, your immune system responds with an influx of inflammatory cells that target the underlying bacteria or viruses. These immune cells migrate from your blood into the infected tissue in order to release a cocktail of pro-inflammatory proteins and help eliminate the infectious threat.
During this inflammatory response, the blood vessel barrier becomes “leaky.” This allows for an even more rapid influx of additional immune cells. Once the infection resolves,........ Read more »
Gong, H., Rehman, J., Tang, H., Wary, K., Mittal, M., Chatturvedi, P., Zhao, Y., Komorova, Y., Vogel, S., & Malik, A. (2015) HIF2α signaling inhibits adherens junctional disruption in acute lung injury. Journal of Clinical Investigation. DOI: 10.1172/JCI77701
Have you ever wondered how the content of your dreams differs from that of your friends? How about the dreams of people raised in different countries and cultures? It is not always easy to compare dreams of distinct individuals because the content of dreams depends on our personal experiences. This is why dream researchers have developed standardized dream questionnaires in which common thematic elements are grouped together. These questionnaires can be translated into various languages and used........ Read more »
Nielsen, T., Zadra, A., Simard, V., Saucier, S., Stenstrom, P., Smith, C., & Kuiken, D. (2003) The Typical Dreams of Canadian University Students. Dreaming, 13(4), 211-235. DOI: 10.1023/B:DREM.0000003144.40929.0b
In the summer of 2010, over 20 million people were affected by the summer floods in Pakistan. Millions lost access to shelter and clean water, and became dependent on aid in the form of food, drinking water, tents, clothes and medical supplies in order to survive this humanitarian disaster. It is estimated that at least $1.5 billion to $2 billion were provided as aid by governments, NGOs, charity organizations and private individuals from all around the world, and helped contain the devastating ........ Read more »
Mueller V, Gray C, & Kosec K. (2014) Heat Stress Increases Long-term Human Migration in Rural Pakistan. Nature climate change, 182-185. PMID: 25132865
Miralles, D., Teuling, A., van Heerwaarden, C., & Vilà-Guerau de Arellano, J. (2014) Mega-heatwave temperatures due to combined soil desiccation and atmospheric heat accumulation. Nature Geoscience, 7(5), 345-349. DOI: 10.1038/ngeo2141
Does morality depend on the time of the day? The study "The Morning Morality Effect: The Influence of Time of Day on Unethical Behavior" published in October of 2013 by Maryam Kouchaki and Isaac Smith suggested that people are more honest in the mornings, and that their ability to resist the temptation of lying and cheating wears off as the day progresses. In a series of experiments, Kouchaki and Smith found that moral awareness and self-control in their study subjects decreased in the........ Read more »
Gunia BC, Barnes CM, & Sah S. (2014) The Morality of Larks and Owls: Unethical Behavior Depends on Chronotype as Well as Time of Day. Psychological science. PMID: 25287664
A fully rational approach to task completion would involve creating a priority list of tasks based on a composite score of task importance and the remaining time until the deadline. The most important task with the most proximate deadline would have to be tackled first, and the lowest priority task with the furthest deadline last. This sounds great in theory, but it is quite difficult to implement. A substantial amount of research has been conducted to understand how our moods, distractability a........ Read more »
Tu, Y., & Soman, D. (2014) The Categorization of Time and Its Impact on Task Initiation. Journal of Consumer Research, 41(3), 810-822. DOI: 10.1086/677840
Back in 2001, when we first began studying how regenerative cells (stem cells or more mature progenitor cells) enhance blood vessel growth, our group as well as many of our colleagues focused on one specific type of blood vessel: arteries. Arteries are responsible for supplying oxygen to all organs and tissues of the body and arteries are more likely to develop gradual plaque build-up (atherosclerosis) than veins or networks of smaller blood vessels (capillaries). Once the amount of plaque in an........ Read more »
Paul JD, Coulombe KL, Toth PT, Zhang Y, Marsboom G, Bindokas VP, Smith DW, Murry CE, & Rehman J. (2013) SLIT3-ROBO4 activation promotes vascular network formation in human engineered tissue and angiogenesis in vivo. Journal of molecular and cellular cardiology, 124-31. PMID: 24090675
Fasting is defined as either completely abstaining from or minimizing food intake for a defined period time - ranging from about 12 hours to even a few weeks. Calorie restriction, on the other hand, refers to an overall reduction in the daily calorie intake by about 20%-40% without necessarily reducing the meal intake frequency. Although calorie restriction is well-suited for weight loss and thus also reduces the risk of chronic diseases such as diabetes or heart disease, proponents of fasting c........ Read more »
Cheng, C., Adams, G., Perin, L., Wei, M., Zhou, X., Lam, B., Da Sacco, S., Mirisola, M., Quinn, D., Dorff, T.... (2014) Prolonged Fasting Reduces IGF-1/PKA to Promote Hematopoietic-Stem-Cell-Based Regeneration and Reverse Immunosuppression. Cell Stem Cell, 14(6), 810-823. DOI: 10.1016/j.stem.2014.04.014
Macrophages are important immune cells which regulate inflammation, host defense and also act as a 'clean-up crew'. They recognize, kill and engulf bacteria as well as cellular debris, which is generated during an acute infection or inflammation. As such, they are present in nearly all tissues of the body, engaging in 24/7 surveillance. Some macrophages in a tissue are derived from circulating blood monocytes which migrate into the tissue and become "phagocytic" - acquire to ........ Read more »
Okabe Y, & Medzhitov R. (2014) Tissue-specific signals control reversible program of localization and functional polarization of macrophages. Cell, 157(4), 832-44. PMID: 24792964
All over the world, young children are exposed to classic fairy tales, myths and other stories. Most kids love hearing the stories, but in addition to being a fun activity, story-telling is also thought of as an educational tool which can promote moral reasoning and honesty. Conventional wisdom suggests that hearing fairy tales in which dishonest protagonists are punished might help convince the listeners to become truth-tellers. There is surprisingly little scientific data to back up this conve........ Read more »
Lee K, Talwar V, McCarthy A, Ross I, Evans A, & Arruda C. (2014) Can Classic Moral Stories Promote Honesty in Children?. Psychological science. PMID: 24928424
Researchers at Facebook, Inc., the University of California, San Francisco (UCSF) and Cornell University teamed up to study whether manipulating the News Feeds of Facebook users would affect the emotional content of the users' status updates or postings. They recently published their findings in the PNAS paper "Experimental evidence of massive-scale emotional contagion through social networks" and suggest that they have found evidence of an "emotional contagion", i.e. t........ Read more »
Kramer, A., Guillory, J., & Hancock, J. (2014) Experimental evidence of massive-scale emotional contagion through social networks. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.1320040111
Many research groups, including our own group, have been able to isolate stem cells from human fat. However, when it came to using this cells for treating cardiovascular disease, the cells behaved in a manner that we had not anticipated.... Read more »
Zuk PA, Zhu M, Mizuno H, Huang J, Futrell JW, Katz AJ, Benhaim P, Lorenz HP, & Hedrick MH. (2001) Multilineage cells from human adipose tissue: implications for cell-based therapies. Tissue engineering, 7(2), 211-28. PMID: 11304456
Rehman J, Traktuev D, Li J, Merfeld-Clauss S, Temm-Grove CJ, Bovenkerk JE, Pell CL, Johnstone BH, Considine RV, & March KL. (2004) Secretion of angiogenic and antiapoptotic factors by human adipose stromal cells. Circulation, 109(10), 1292-8. PMID: 14993122
The family of cholesterol lowering drugs known as 'statins' are among the most widely prescribed medications for patients with cardiovascular disease. Large-scale clinical studies have repeatedly shown that statins can significantly lower cholesterol levels and the risk of future heart attacks, especially in patients who have already been diagnosed with cardiovascular disease. A more contentious issue is the use of statins in individuals who have no history of heart attacks, strokes or........ Read more »
Abramson, J., Rosenberg, H., Jewell, N., & Wright, J. (2013) Should people at low risk of cardiovascular disease take a statin?. BMJ, 347(oct22 3). DOI: 10.1136/bmj.f6123
Reading literary fiction can be highly pleasurable, but does it also make you a better person? Conventional wisdom and intuition lead us to believe that reading can indeed improve us. However, as the philosopher Emrys Westacott has recently pointed out in his essay for 3Quarksdaily, we may overestimate the capacity of literary fiction to foster moral improvement. A slew of scientific studies have taken on the task of studying the impact of literary fiction on our emotions and thoughts. Some of t........ Read more »
Johnson, D., Huffman, B., & Jasper, D. (2014) Changing Race Boundary Perception by Reading Narrative Fiction. Basic and Applied Social Psychology, 36(1), 83-90. DOI: 10.1080/01973533.2013.856791
Optimizing such tailored checklists, understanding why some studies indicate benefits of checklists whereas others do not and re-evaluating the efficacy of checklists in the non-academic setting will all require a substantial amount of future research before one can draw definitive conclusions about the efficacy of checklists. Regulatory agencies in Canada and the United Kingdom should reconsider their current mandates. Perhaps an even more important lesson to be learned is that health regulator........ Read more »
Urbach DR, Govindarajan A, Saskin R, Wilton AS, & Baxter NN. (2014) Introduction of surgical safety checklists in Ontario, Canada. The New England Journal of Medicine, 370(11), 1029-38. PMID: 24620866
Like many other insects, field crickets (Gryllinae) use a courtship song to attract potential mates and initiate mating. A team of researchers headed by Shelley Adamo at Dalhousie University has recently discovered a surprising trigger which speeds up this dating process - a virus. In their recent article “A viral aphrodisiac in the cricket Gryllus texensis” published in the Journal of Experimental Biology, the researchers found that a pathogenic insect virus (iridovirus) is able to ........ Read more »
Adamo, S., Kovalko, I., Easy, R., & Stoltz, D. (2014) A viral aphrodisiac in the cricket Gryllus texensis. Journal of Experimental Biology. DOI: 10.1242/jeb.103408
In January 2014, the two papers “Stimulus-triggered fate conversion of somatic cells into pluripotency” and “Bidirectional developmental potential in reprogrammed cells with acquired pluripotency” published in the journal Nature by Haruko Obokata and colleagues took the world of stem cell research by surprise.... Read more »
Obokata H, Wakayama T, Sasai Y, Kojima K, Vacanti MP, Niwa H, Yamato M, & Vacanti CA. (2014) Stimulus-triggered fate conversion of somatic cells into pluripotency. Nature, 505(7485), 641-7. PMID: 24476887
Is it possible to be overweight or obese and still be considered healthy? Most physicians advise their patients who are overweight or obese to lose weight because excess weight is a known risk factor for severe chronic diseases such as diabetes, high blood pressure or cardiovascular disease. However, in recent years, a controversy has arisen regarding the actual impact of increased weight on an individual’s life expectancy or risk of suffering from heart attacks. Some researchers argue tha........ Read more »
Kramer CK, Zinman B, & Retnakaran R. (2013) Are metabolically healthy overweight and obesity benign conditions?: A systematic review and meta-analysis. Annals of internal medicine, 159(11), 758-69. PMID: 24297192
A recent paper published in Circulation Research, a major cardiovascular research journal, challenges the assumption that the scores a grant application receives can reliably predict the future impact of the research.... Read more »
Narasimhan Danthi, Colin O Wu, Peibei Shi, & Michael S Lauer. (2014) Percentile Ranking and Citation Impact of a Large Cohort of NHLBI-Funded Cardiovascular R01 Grants. Circulation Research. info:/
Two scientific papers that were published in the journal Nature in the year 2000 marked the beginning of engineering biological circuits in cells. The paper "Construction of a genetic toggle switch in Escherichia coli" by Timothy Gardner, Charles Cantor and James Collins created a genetic toggle switch by simultaneously introducing an artificial DNA plasmid into a bacterial cell. This DNA plasmid contained two promoters (DNA sequences which regulate the expression of genes) and two rep........ Read more »
Does watching TV and playing video games affect our empathy and willingness to engage in pro-social behavior? A team of international psychology researchers studied over 2,000 adolescents (mean age 21 years, 60% female and 40% male) in seven countries (Australia, China, Croatia, Germany, Japan, Romania and the United States) to determine whether there is a link between the media they consume and their levels of empathy and pro-social behavior. ... Read more »
Sara Prot, Douglas A. Gentile, Craig A. Anderson, Kanae Suzuki, Edward Swing, Kam Ming Lim, Yukiko Horiuchi, Margareta Jelic, Barbara Krahé, Wei Liuqing.... (2013) Long-Term Relations Among Prosocial-Media Use, Empathy, and Prosocial Behavior. Psychological Science. DOI: 10.1177/0956797613503854
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