scholarly journals THE KINETICS OF STARVATION

1925 ◽  
Vol 7 (6) ◽  
pp. 709-718 ◽  
Author(s):  
Norman C. Wetzel
Keyword(s):  
Body Protein ◽  
Prolonged Starvation ◽  
Suitable Transformation ◽  
Fat Reserves ◽  
Loss Of Weight ◽  
The Law ◽  
Kinetics Of

1. The loss of weight in pigeons subjected to prolonged starvation on water alone may be accurately represented by an appropriate form of the law of autocatakinesis. 2. This function, within proper limitations, gives a definite indication as to the nature and character of the fundamental reactions involved. In addition, it provides quantitative measures of the relative progress and importance of these reactions. 3. Analytically, the process of starvation consists of two nearly symmetrical cycles, corresponding chemically to the destruction of the carbohydrate-fat reserves and to the decomposition of body protein. 4. A suitable transformation overcoming certain difficulties inherent in the general form of the law is discussed and applied to the data reported.

scholarly journals THE KINETICS OF STARVATION

1924 ◽  
Vol 7 (2) ◽  
pp. 269-286
Author(s):  
Norman C. Wetzel
Keyword(s):  
Weight Loss ◽  
Close Agreement ◽  
Relative Weight ◽  
Body Protein ◽  
Simple Modification ◽  
Actual Weight ◽  
Homogeneous Systems ◽  
Fat Reserves ◽  
Relative Weight Loss ◽  
Kinetics Of

1. The relative weight loss of pigeons on starving rations may be represented by a simple modification of the law of autocatalysis. 2. An equation giving the actual weight of the animals during the 53 day period of the experiment is derived by means of the hypothesis that the process of inanition is governed by the simultaneous velocity relations between two independent, homogeneous systems, such that MT = (A0 → 0) + (B0 → BC) in which A is taken proportional to the amount of carbohydrate-fat reserves, and B proportional to the amount of reacting body protoplasm. 3. The course of starvation is governed by the rate of destruction of body protein, but it is modified by the amount and by the rate of destruction of reserve materials. 4. The processes of breaking down tissues are analogous to those by which tissues are synthesized. 5. The close agreement between observed and calculated values suggests that the original assumptions set forth in deriving the foregoing equations were valid. 6. Attention is called to the fact that the time of onset of beriberi in pigeons is coincident with the half period of starvation.

Adaptation to prolonged starvation in the rat: curtailment of skeletal muscle proteolysis

1981 ◽  
Vol 241 (4) ◽  
pp. E321-E327 ◽  
Author(s):  
M. N. Goodman ◽  
M. A. McElaney ◽  
N. B. Ruderman
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Early Event ◽  
Body Protein ◽  
Fed State ◽  
Prolonged Starvation ◽  
Obese Rats ◽  
Old Rats

Previous studies have established that 16-wk-old nonobese and obese rats conserve body protein during prolonged starvation. To determine the basis for this, protein synthesis and degradation in skeletal muscle were evaluated in the isolated perfused hindquarters of these rats, in the fed state and when starved for 2, 5, 10, and 11 days. Rats aged 4 and 8 wk were used as a comparison. The results indicate that the response to starvation depends on several factors: the age of the rat, its degree of adiposity, and the duration of the fast. An early event in starvation was a decline in muscle protein synthesis. This occurred in all groups, albeit this reduction occurred more slowly in the older rats. A later response to starvation was an increase in muscle proteolysis. This occurred between 2 and 5 days in the 8-wk-old rats. In 16-wk-old rats it did not occur until between 5 and 10 days, and it was preceded by a period of decreased proteolysis. In 16-wk-old obese rats, a decrease in proteolysis persisted for upwards of 10 days and the secondary increase was not noted during the period of study. The data suggest that the ability of older and more obese rats to conserve body protein during starvation is due, in part, to a curtailment of muscle proteolysis. This adaptation seems to correlate with the availability of lipid fuels.

Correction of acidosis in humans with CRF decreases protein degradation and amino acid oxidation

1993 ◽  
Vol 265 (2) ◽  
pp. E230-E235 ◽  
Author(s):  
D. Reaich ◽  
S. M. Channon ◽  
C. M. Scrimgeour ◽  
S. E. Daley ◽  
R. Wilkinson ◽  
...  
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Amino Acid ◽  
Sodium Chloride ◽  
Sodium Bicarbonate ◽  
Acid Oxidation ◽  
Body Protein ◽  
Amino Acid Oxidation ◽  
Kinetics Of ◽  
Amino Acid Concentrations

The effect of correction of acidosis in chronic renal failure (CRF) was determined from the kinetics of infused L-[1-13C]leucine. Nine CRF patients were studied before (acid) and after two 4-wk treatment periods of sodium bicarbonate (NaHCO3) and sodium chloride (NaCl) (pH: acid 7.31 +/- 0.01, NaHCO3 7.38 +/- 0.01, NaCl 7.30 +/- 0.01). Leucine appearance from body protein (PD), leucine disappearance into body protein (PS) and leucine oxidation (O) decreased significantly with correction of acidosis (PD: acid 122.4 +/- 6.1, NaHCO3 88.3 +/- 6.9, NaCl 116.2 +/- 9.1 mumol.kg-1.h-1, acid vs. NaHCO3 P < 0.01, NaHCO3 vs. NaCl P < 0.01, acid vs. NaCl NS; PS: acid 109.4 +/- 5.6, NaHCO3 79.0 +/- 6.3, NaCl 101.3 +/- 7.7 mumol.kg-1.h-1, acid vs. NaHCO3 P < 0.01, NaHCO3 vs. NaCl P < 0.01, acid vs. NaCl NS; O: acid 13.0 +/- 1.2, NaHCO3 9.2 +/- 0.9, NaCl 15.0 +/- 1.9 mumol.kg-1.h-1, acid vs. NaHCO3 P < 0.05, NaHCO3 vs. NaCl P < 0.01, acid vs. NaCl NS). There were no significant changes in plasma amino acid concentrations. These results confirm that correction of acidosis in chronic renal failure removes a potential catabolic factor.

scholarly journals THE KINETICS OF SENESCENCE

1924 ◽  
Vol 6 (3) ◽  
pp. 245-257 ◽  
Author(s):  
Samuel Brody
Keyword(s):  
Chemical Reactions ◽  
Growing Period ◽  
Exponential Law ◽  
The Law ◽  
Kinetics Of ◽  
Constant Percentage

The course of decline of vitality with age due to the process of senescence, when not complicated by the process of growth, follows a simple exponential law; that is the degree of vitality or of senescence (defining vitality as the reciprocal of senescence) at any moment is, regardless of age, a constant percentage of the degree of vitality or senescence of the preceding moment. This exponential law is the same as the law of monomolecular change in chemistry. During the actively growing period of life the index of vitality rises, due to the process of growth and the course of vitality in the case when the growing period is included in the vitality curve, follows a rising and falling course. This rising and falling course may often be represented by an equation containing two exponential terms which is practically the equation used to represent the course of accumulation and disappearance of a substance as the result of two simultaneous consecutive monomolecular chemical reactions.

Effects of feeding level and starvation on growth and water and protein content in juvenile redclaw crayfish, Cherax quadricarinatus (von Martens)

1996 ◽  
Vol 47 (5) ◽  
pp. 745 ◽  
Author(s):  
H Gu ◽  
AJ Anderson ◽  
PB Mather ◽  
MF Capra
Keyword(s):  
Body Weight ◽  
Protein Content ◽  
Water Content ◽  
Total Protein ◽  
Simultaneous Increase ◽  
Total Protein Content ◽  
Body Protein ◽  
Cherax Quadricarinatus ◽  
Feeding Level ◽  
Loss Of Weight

Effects of feeding level and starvation on growth, water content and protein content were examined in juvenile Cherax quadricarinatus. Gain in body weight was positively related to feeding level. An increase in feeding level resulted in a decrease in water content and an increase in protein content. Although the majority of juveniles were able to tolerate starvation for at least 12 days, deprivation of feeding caused a loss of weight and a gradual decrease in protein content combined with a simultaneous increase in water content. Total protein content was reduced by 3.9% in juveniles starved for three days and by 8.3% in those starved for 12 days. Normal body protein content, however, was recovered within six days after subsequent feeding in juveniles that were deprived of food for 12 days.

Effect of NIDDM on the Kinetics of Whole-Body Protein Metabolism

Diabetes ◽  
1994 ◽  
Vol 43 (2) ◽  
pp. 318-328 ◽  
Author(s):  
R. Gougeon ◽  
P. B. Pencharz ◽  
E. B. Marliss
Keyword(s):  
Protein Metabolism ◽  
Whole Body ◽  
Body Protein ◽  
Kinetics Of

A New Model for Interpass Softening Based on the Strain Hardening Rate Prior to Unloading

2005 ◽  
Vol 500-501 ◽  
pp. 15-26 ◽  
Author(s):  
John J. Jonas ◽  
Evgueni I. Poliak
Keyword(s):  
Strain Hardening ◽  
Microalloyed Steels ◽  
Precipitation Kinetics ◽  
New Model ◽  
Volume Fractions ◽  
Input Parameters ◽  
Important Input ◽  
The Law ◽  
Kinetics Of ◽  
Strain Hardening Rate

It is shown that the kinetics of softening between mill passes can be modeled more simply when the normalized strain (reduction) per pass is employed rather than the conventional strain. This method requires a second important input, namely the strain hardening rate at the end of preloading. Using this approach, the number of input parameters and experiments required for their determination are drastically reduced. The use of the Law of Mixtures to describe the behaviors of the recrystallized and unrecrystallized volume fractions is then illustrated. Finally, the approach required for quantifying the precipitation kinetics (in microalloyed steels) is described.

scholarly journals HETERO TRANSITIONS BASED ON - TlGaSe2 - - CuInSe2

2021 ◽  
Author(s):  
A.Ch. Matiyev ◽  
R.T. Uspazhiev
Keyword(s):  
Relaxation Time ◽  
Current Voltage ◽  
Wide Range ◽  
The Law ◽  
First Time ◽  
Kinetics Of

The current-voltage and lux-ampere characteristics, as well as the photovoltage spectra and the lux dependence of the photovoltage in the gate and photodiode modes of the p-TlGaSe2 - p-CuInSe2 heterojunction obtained for the first time are studied. It was found that this heterostructure has a pronounced diode character. The I - V characteristic of the structure under study is characterized by the fact that at low voltages it obeys well the law I ~ exp (eU / βkT). The photovoltage spectrum covers a wide range of wavelengths (0.55 - 1.85 µm). In this case, pronounced maxima are observed at λ = 0.59 and λ = 0.95 μm. The relaxation time τ determined from the kinetics of the photo-voltage in the valve mode is ~ 20 μs.

scholarly journals Correction of acidosis in hemodialysis decreases whole-body protein degradation.

1997 ◽  
Vol 8 (4) ◽  
pp. 632-637 ◽  
Author(s):  
K A Graham ◽  
D Reaich ◽  
S M Channon ◽  
S Downie ◽  
T H Goodship
Keyword(s):  
Renal Failure ◽  
Protein Degradation ◽  
Protein Turnover ◽  
Whole Body ◽  
Body Protein ◽  
Chronic Metabolic Acidosis ◽  
Optimal Correction ◽  
Kinetics Of ◽  
Amino Acid Concentrations

Correction of acidosis in hemodialysis (HD) decreases protein degradation. The effect of the correction of chronic metabolic acidosis in chronic renal failure patients treated with HD was determined from the kinetics of infused L-[1-(13)C]leucine. Six HD patients were studied before (acid) and after (bicarbonate) correction of acidosis (pH: acid 7.36 +/- 0.01, bicarbonate 7.40 +/- 0.01, P < 0.005). Leucine appearance from body protein (PD) and leucine disappearance into body protein (PS) decreased significantly with correction of acidosis (PD: acid 180.6 +/- 7.3, bicarbonate 130.9 +/- 7.2 mumol.kg-1.h-1, P < 0.005; PS: acid 172.3 +/- 6.8, bicarbonate 122.0 +/- 6.8 mumol.kg-1.h-1, P < 0.005). There was no significant change in leucine oxidation or plasma amino acid concentrations. These results demonstrate that optimal correction of acidosis in HD is beneficial in terms of protein turnover and may improve long-term nutritional status in HD.

Starvation as a Treatment of Obesity: The Need to Conserve Body Protein

Physiology ◽  
1988 ◽  
Vol 3 (1) ◽  
pp. 21-24 ◽  
Author(s):  
Y Le Maho ◽  
J-P Robin ◽  
Y Cherel
Keyword(s):  
Sudden Death ◽  
Human Obesity ◽  
Protein Loss ◽  
Prolonged Fasting ◽  
Body Protein ◽  
Fat Reserves ◽  
Severely Obese ◽  
Treatment Of Obesity ◽  
Complete Starvation

Starvation has successfully been used to treat severe human obesity but may be dangerous due to excessive loss of body protein. Obese humans when starving use fat and spare protein as effectively as those animals that spontaneously undergo prolonged fasting after accumulating large fat reserves. Nevertheless, slow loss of protein during complete starvation may in severely obese persons lead to a cumulative protein loss that leads to sudden death before the fat reserves are depleted.

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