Bio Aging Midterm Discussion papers and Aging patterns.txt
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Istvan Szabo
First to determine the Type III aging pattern, doing research on oak trees (theorized from Raymond Pearl)

Alex Comfort
Dog breeding studies: showed that lifespan increases in dog breeds with larger brain:body ratio

Rajindal Sohal
Showed that increase in metabolic activity, along with an increase in temperature causes increase in mortality rates in houseflies

Weindruch & Walford
 showed that reduced calorie diet in mice showed:
 1. Increase in % survival
 2. Decrease in body mass
 3. decrease in TUMOR mortality

James Carey et. al
 Carried out LARGEST study with MedFlys: showing NOT exhibiting Gompertz pattern.
 Flies had higher survival rates as age INCREASED

Muggleton & Danielli
discovered that immortal amoebas could be transformed to 'spanned' amoebas with NUTRIENT DEPRIVATION, even briefly

Thomas and Dennis Nyberg
 Showed Vitamin E supplementation for paramecium cells increases lifespan
 Data showed a Type I Gompertzian slope curve

Hamilton and Mestler
 Showed castrated males vs intact had more higher life expectancy.
 Also showed mentally retarded males exhibited hyperbolic pattern of agerelated mortality increase

Westendorp and Kirkwood
 Looked at British aristocracy
 showed that women age of first child birth and # of children correlate with longevity of females
 Longer you wait until first child, and if only have 1 child: show longest longevity

Massie, et al. (p601)
 Using Drosophila melanogaster, show the increase in Vitamin A consumption is correlated to increase in longevity
 Too much Vit A can be detrimental, however, causing a decrease in longevity

Thomas dissertation related to redundancy and damage rate:
 gene redundancy R: Determines how RAPID mortality rate Increases
 redundancy may improve cell survivorship by reducing rate of loss of genetic info
 small damage rate u (mew) and large redundancy = increase in survival

Gompertz pattern
 qx= qo (e)a(x)^n with N=1
 Type I:
 Linear curve on a semilogarithmic mortality plot
 Concave slope on double log plot
 delta ln qx is POSITIVE and CONSTANT, so doubledelta q is ZERO (inverse Gomp w/type III shows neg delta lnqx)
 Declining life expectancy with age
 Constant MRDT with age

Hyperbolic Pattern
 qx=qo(e)a(x)^n
 Type I:
 Mortality INCREASES at accelerating rate
 ConCAVE slope for semi and double log plot
 delta lnqx is POSITIVE and INCREASING
 Declining lifeexpectancy with age
 Declining MRDT with age

Weibull Pattern
 qx=qo(x+1)^n with n > 0
 ConVEX slope on semilog plot
 Linear on double log plot
 delta lnqx Positive and DECREASING, double delta lnq is NEGATIVE
 Declining lifeexpectancy with age
 Increasing mortality rate doubling time w/age

Logistic Pattern
 lx = 1(1(1u)^x)^R
 Type I:
 Slowest rate of senescence
 Convex slope on semilogarithmic (and double) mortality plot
 Declining life expectancy with age
 Increasing MRDT with age
 ONLY with NO upper limit to Maximum lifespans

Kapitanov and Aksenov
 In stationary phase, immortal bacteria (Prokaryotes) exhibited REDUCED viability & INCREASED mortality
 Followed Gompertz pattern: decrease in life expectancy with age
 bacteria termed immortal b/c although they have rate of aging, they can sustain damage as long as their growth rates are high

Type I vs II vs III
 type I: Prob of death (qx) continuously INCREASING, with Life expectancy (ex) going DOWN
 type II: qx and ex stay SAME
 type III: probability of death (qx) DECREASES

dx
 # of prop. of ppl dying from age x to x+t
 dx=lx  l(x+t)

qx (probability of death)
qx=dx/lx

Lx
 avg # of prop. of ppl surviving from age x to x+t
 Lx= (lx + l(x+t))/2

Tx
 Total # of organismageintervals in lifetable
 Tx=sum of Lx (Lx + L(x+t) + L(x+2t)...)

ex (life expectancy)
ex = (Tx)(t) / (lx)

lx
# of prop. of ppl surviving at age x


t
time interval b/w survival measurements