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2010

January 14th, 2010

Ranusz, Cutting Edge

Janusz Rak (Jack Cole Chair in Pediatric Hematology/Oncology and Associate Professor, Department of Pediatrics, McGill University).
The siren song of cancer cells – lies, deceit and misinformation in cellular communication underlying disease.
Now available as a podcast. An effective treatment of complex diseases, especially cancer, may lie in grasping their mechanisms at different levels of biological hierarchy. While much research currently concentrates on understanding how various genes cause cancer from within a cell, much can be learned from studies on what happens between cells, and in their relations to their surroundings. In this regard, cancer cells are not only ‘antisocial’, but also exhibit a ‘gang culture’, whereby they act in concert to achieve certain pathological ends. This is illustrated by ‘coercion’ of normal tissues, such as blood vessels or bone marrow, to collaborate with the tumor cell group, and in ‘corrupting’ influences within it. These influences are exerted through several means of abnormal cell-to-cell communication, one of which is sending cancer-causing proteins (oncoproteins) toward other cells in a form of structures called microvescicles. The latter can trigger aberrant behavior of otherwise non-aggressive cells, which makes them a part of the disease process. The challenge is to learn more about and from microvescicles, and ultimately block the ‘siren song’ of cancer cells.

February 11th, 2010

Andrews, Cutting Edge

Dr. Mark Andrews (Department of Chemistry, McGill University)
Materials Make Light Work – Or, “Image is Everything”

NEW! Thanks to the generous support of CAMBAM (The Centre for Applied Mathematics in Bioscience and Medicine), you can now view a video recording (with slides) of this presentation.
What do butterfly wings, Venus flower baskets and healthy doses of elements from the Periodic Table have to do with conveying digital data, music, voice and video by light? They can all be designed to make “light work”. Light is rather mysterious stuff; but Nature and scientists have found ways to make extraordinary materials in order to control light so that it can be used to transmit information and render images. With animations, demonstrations and humour, this talk begins by examining the origins of Canada’s optical internet as we forage among some early Greek, Roman and Napoleonic inventions. We then explore how species of aquatic micro-organisms and sponges construct intricate “glass houses” and woven optical fibre baskets; and why butterflies and beetles have such exquisite coloration. The findings may teach us how to make optical fibre and ultra-small optical circuits from the constituents of sea water, biomolecules, or patterns of solid and liquid crystals when combined with some fancy engineering. We conclude by describing how chemistry can be used to build optical circuits on silicon chips to manage information flow like that from iTunes® and YouTube®. And if “image is everything”, we point out ways in which chemistry makes “light work” out of the revolution in image-making: like the creation of an ultra-thin, light weight plastic, flexible liquid crystal colour display; and a programmable animated poster made by printing with special inks that emit light. Throughout the talk, concepts are presented together with examples in a simple manner to explain how materials make light work.

March 11, 2010

 Vincent Warwick

Dr. Warwick F. Vincent (Centre for Northern Studies / Centre d'Etudes Nordiques [CEN], Université Laval)
Climate change, ecosystem collapse and cascading regime shifts in the Canadian Arctic
Now available as a podcast. The Canadian Arctic contains a remarkably diverse variety of aquatic ecosystem types, including permafrost thaw lakes, large rivers discharging to the Arctic Ocean, lagoons and other coastal ecosystems, and perennially ice-capped, solar-heated lakes. Our analyses of the molecular microbiology of these waters have revealed diverse communities in each of the three domains of microbial life, with implications for biogeography, food-web structure and biogeochemical processes, including greenhouse gas fluxes. The Arctic is currently warming at twice the global average, and some of these aquatic ecosystems have begun to experience step-like changes in their physical and ecological regimes. Our observations imply that global climate change will be increasingly accompanied by discontinuous shifts in aquatic ecosystem structure and function.

April 8, 2010

Pr. Gil Holder

Dr. Gil Holder (Department of Physics, McGill)

The First Stars and the End of the Dark Ages
Now available as a podcast. We know a lot about the universe as it was when it was 300,000 years old, through studies of the cosmic microwave background, and we can measure the local universe to learn a lot about the last few billion years of its nearly 14 billion years. However, there is a period in between (roughly the first half a billion years) which is extremely difficult for us to see because there were no sources of light. These cosmic ``dark ages'' ended when the first stars turned on, providing the first view of the somewhat evolved universe.
Understanding this period is expected to give new insights into dark matter, dark energy, star formation, and the physics of the early universe. This is a new frontier in astrophysics and cosmology, combining observations from the largest radio, mm-wave, optical, and gamma-ray telescopes, and involving some of the most demanding computational projects in astronomy and astrophysics.

September 9, 2010

 Yogita Chudasama

Dr. Yogita Chudasama (Department of Psychology, McGill)
Dissecting the components of animal behaviour as a window into the human mind
Watch the podcast. So much of our understanding of basic sensory and motor functions of the brain has derived from research in animals. Recently, the use of experimental animals has been extended to study more complex aspects of cognition, such as planning and organization, behavioural control and decision-making. How far can animal models inform us of the complex features of human cognition? While the specific behaviours of different species diverge from humans in obvious ways (consider for example, the subterranean lifestyle of a rat), their brains have the same basic circuitry, raising the possibility that they support analogous cognitive operations.

In this lecture, I will discuss how neuroscientists have been able to successfully exploit a conceptual framework, derived from research in human experimental psychology, which decomposes cognition into its basic building blocks. I will present evidence that many of these cognitive components are surprisingly human-like in experimental animals as diverse as nonhuman primates and rodents. Finally, I will argue that the combination of careful behavioural testing and targeted manipulation of specific circuits in the brain of experimental animals is presently our most effective means for understanding the basic neural elements of human cognition. These elements, whose neural bases are only now being discovered, are perturbed in common human brain disorders that involve emotional dysregulation, cognitive dysfunction, and even psychoses.

October 14, 2010

Dr. Maya Saleh

Dr. Maya Saleh (Faculty of Medicine, McGill)
Inflammation — the fuel of cancer: extinguishing the fire to stop the disease
Watch the podcast. What is an inflammatory response? How is it triggered and terminated? Is inflammation a friend or a foe? We have all experienced the signs of inflammation in the form of redness, swelling and heat around a blister or fever when infected with a bacteria or a virus. Indeed, inflammation is our innate immune response to “danger”, be it an invading pathogen, a skin cut, or the presence of transformed or dying cells. The physiological role of inflammation is to defend our body and restore normalcy or homeostasis. However, when inflammation is deregulated, it is at the basis of inflammatory diseases and is the fuel of cancer growth.
In the last decade, the master “switches” of inflammation or the sensors of “danger” referred to as pathogen/danger recognition receptors have been identified. This discovery has changed dramatically the way we perceive the role of inflammation in health and disease, leading in many cases to direct therapeutic applications.
In this lecture, I will discuss what we have recently learned on the role of our innate immune response in inflammatory diseases and cancer, with a focus on intestinal pathologies, including inflammatory bowel diseases (IBD) and colorectal cancer. I will address the conundrum of how we co-exist with a whopping number of bacteria in our gut without eliciting an inflammatory reaction, whether the bacteria in our intestinal flora are “good” or “bad”, and whether we could modify our diet to change the composition of these bacteria for good health. I will also review the current therapies of IBD and colitis-associated cancer and discuss the potential need to revisit them.

November 11, 2010

 David Sauchyn

Dr. David Sauchyn (University of Regina)
How Might Global Warming affect the Variable Hydroclimate of Western Canada?
Watch the podcast. Canada’s western interior has one of the world's most variable climates, with severe drought and torrential rainstorms experienced in recent years. The extreme climate events in this region have been some of the most costly natural disasters in Canada history. Climate models suggest that this hydroclimatic variability could be amplified by global warming — presenting a more challenging future scenario than the projected shifts in average conditions.

To appreciate how global warming might affect the variable hydroclimate of western Canada, we first must understand the internal (natural) short-term variability. Because some climate cycles are as long or longer than most weather station records, we use the response of tree growth to climate to generate proxy records of the hydroclimate of the past millennium. The long climate records indicate that western water policy and management practices were established during a period of intense, but not sustained drought, and that adjustments may be required to sustain land and water use under a hydrologic regime that has elements of previous regimes and global warming.

December 9, 2010

Dr. Robert Reisz

Dr. Robert Reisz (University of Toronto)
From Embryos to Adults: The Life and Times of a Dinosaur
Dinosaurs have undergone a remarkable renaissance in recent decades. Far from being sluggish reptilian monsters doomed to extinction, new discoveries and new methods of scientific investigation have revealed dinosaurs as complex, highly active animals capable of sophisticated behaviors and as one of the most diverse and successful groups of land creatures in the history of life on Earth.

My research team has studied in detail the anatomy and life history of Massospondylus, a dinosaur that lived in what is today southern Africa some 200 million years ago. Although not as visually striking or as large as certain other dinosaurs, Massospondylus is unique among all dinosaurs in being known from many excellently preserved skulls and skeletons. These remains, along with the remarkable discovery of nests of this dinosaur — some containing eggs with preserved unhatched embryos — has allowed us to reconstruct the life and times of this dinosaur in minute detail from an embryo all the way to a full adult, a feat unmatched in previous dinosaur research. As such, the tale of Massospondylus serves as a case study for the ways science can now bring ancient animals and environments back to life.