The Systems Biology of COVID-19 and the SARS-CoV-2 virus. The class will build a foundation that includes the emergence of complexity, simple biological subsystems, their reductionist and equivalent toy and organ-chip models, and the measurements required to specify model architecture and parameters. Applications to biology, physiology, medicine, chemical and biological defense, pharmacology, drug discovery, and toxicology. UGrad: PHYS 240 01 and BME 290B; Grad: PHYS 326 and BME 395C.
Tuesday, January 17, 2012
Asgn_4C_Class_4_Article_6_2012_01_18
Read Article 6: Knut. Schmidt-Nielsen. Organ size and tissue metabolism. In: Scaling: Why is animal size so important?,Anonymous New York:Cambridge University Press, 1984, p. 90-98.. The primary goal is for you to be able to explain the challenges in building multiple, compatible organs on a chip.
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Don't get hung up on the controversies of who measured what when. We don't care about specific metabolic rates or exponents! As you will see, S-N is almost entirely phenomenological and not mechanistic on these organ scalings.
ReplyDeleteWill Matloff
ReplyDelete4C/Organ Size and Tissue Metabolism
0. Knew: Relative metabolisms decreases with body size.
1. Learned: The oxygen consumption of tissues changes with body size. In addition, the mitochondria count seems proportional to metabolic rate.
2. Pressing?: What role does energy storage play in this scaling?
3. Presentation: Metabolism in various organs.
4. Thoughts: Physiological scaling presents challenges when trying to fit organs on a chip. Since large animals have tissues and cells that result in a relatively low metabolism, a larger size of these organisms at the chip-size is required to meet energy needs.
Brian Evans
ReplyDelete4C/Organ Size & Tissue Metabolism
0. Knew: That trying to find a standardized basal metabolic rate for specific tissues is quite difficult and depends on many environmental factors.
1. Learned: That when thinking of scaling metabolism one must consider size, density, and number simultaneously (For example, differing metabolic rates can be due to the difference in the number of mitochondria or to the difference in cristae density).
2. Pressing?: Do the allometric relationships seen in basal metabolic rates also apply to heightened metabolic states? I.e. would the metabolic differences between a resting horse vs. a resting mouse be different from a running horse vs. a running mouse?
Also, don't metabolic rates follow oscillatory patterns (circadian, infradian, etc) so their metabolic rate is not constant, rather dynamic?
3. Presentation: Modulating cellular metabolic rates in vitro.
4. Thoughts: So to accurately model an organ on a chip, wouldn't it need to be patient specific? Each patient will have varying metabolic rates, size, age, which can all have significant effects on the intrinsic properties of the tissue of interest.
Ayeeshik Kole
ReplyDelete4C/Organ Size & Tissue Metabolism
0. Knew: Metabolism rate declines with increasing body size.
1. Learned: Organ size changes differently with increasing body size. Kidney, brain, liver all decrease in relative size, but heart, lungs, and skeletal muscle stay the same.
2. Pressing?: What do we know about scaling of cell population ratios in heterogeneous tissues, such as neural tissue?
3. Presentation: Methods of calculating oxygen consumption
4. Thoughts: I thought the studies on the "metabolic equipment" were really interesting and pivotal to introducing the idea that the cellular equipment corresponds to needs.
Erica Curtis
ReplyDelete4C/Organ Size & Tissue Metabolism
0. Knew: An increase in body size results in a lower basal metabolic rate.
1. Learned: I had not really thought much about how the metabolism of similar sized cells in organisms of a range of sizes fits into the trend mentioned above. I knew that different tissues have different levels of metabolism yet had not thought about how this is weighted as organ size either increase/decrease in relative size while others remain the same.
2. Pressing ?: In which tissues would being physically fit alter the rate of metabolism the most? How much of an effect does it have at rest? during exercise?
3. Presentation: The Limits of Cellular Metabolism and its Effect on the Limits of Animal Size
4. Thoughts: Has anyone studied how the isolation of human cells affects the "metabolic equipment" of the cells? Would the new environment of the chip influence these factors?
0. That metabolism and O2 consumption were strongly related or directly correlated in aerobic organisms.
ReplyDelete1. That metabolism could actually be measured in "tissue slices"
2. Is metabolism measurement in ex-vivo tissue really reflective of that in the body, or does the tissue rapidly begin to die when it is removed.
3. I wonder if M. rate varies within a species the same way - ie, does a chihuahua have a higher specific M. rate than a Mastiff? Or, do I have a lower SMR than someone half my size?
Lucas Hofmeister
ReplyDelete4C/Organ Size and Tissue Metabolism
0. Knew: body size is not directly proportional to metabolic rate
1. Learned:
2. Pressing?: how does the function of the organ effect metabolic rate? for example the function of the human brain is different from the function of the mouse brain
3. Presentation: mitochondrial structure and body size
4. Thoughts: is cell size really independent of body size? and how do organelles vary with organ size. It is also interesting that genome size does not necessarily change with animal size, its more about the complexity. maybe complexity is a better measure of metabolic rate
Zach Eagleton
ReplyDelete4C/Tissue Metabolism
0 Knew: Metabolic rate decreases as body size increases.
1 Learned: As body size increases decrease in mitochondria density and decrease in relative organ size, thus lower BMR.
2 Pressing ?: why do the heart/lungs/muscles stay relatively same in respect to body size.
3 Presentation: hemoglobin and cytochrome densities in various organisms.
4 Thoughts: to what extent to cells behave differently in vitro.
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