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Comparative Analysis of Human Growth Hormone in Serum Using SPRi, Nano-SPRi and ELISA Assays
Published on: January 7, 2016
HUMAN GROWTH CURVE
1Department of Genetics, Carnegie Institution of Washington, Cold Spring Harbor.
Insights
Human growth is marked by two key acceleration periods: circumnatal and adolescent. These distinct growth phases, superimposed on a slower residual curve, shape overall development from conception through adulthood.
Area of Science:
- Human biology
- Growth and development studies
- Biostatistics
Background:
- Human growth exhibits complex patterns, not a single linear progression.
- Previous models have not fully captured the distinct phases of accelerated growth.
Purpose of the Study:
- To identify and characterize the primary periods of accelerated human growth.
- To model these growth phases using statistical curves.
- To differentiate accelerated growth from the underlying residual growth curve.
Main Methods:
- Analysis of human growth curves.
- Application of theoretical skew curves (Pearson's Type I) and normal frequency curves for modeling.
- Identification of modal velocities, ranges, and standard deviations for growth cycles.
Main Results:
- Identified two major growth accelerations: circumnatal (peak at birth, skew curve) and adolescent (broader range, normal curve).
- Circumnatal cycle: modal velocity 10.2 kg/year, range 44 months.
- Adolescent cycle: modal velocity 4.5 kg/year, range ~10 years.
- A residual growth curve (conception to 55 years) with low velocity (~2 kg/year) underlies these accelerations.
- No significant third acceleration period was found between ages 3-6 years.
Conclusions:
- Human growth is characterized by two principal, superimposed acceleration cycles: circumnatal and adolescent.
- These cycles, along with a slower residual growth, dictate overall human weight development.
- The underlying mechanisms of these distinct growth accelerations warrant further investigation.
Abstract:
The human growth curve shows two (and only two) outstanding periods of accelerated growth-the circumnatal and the adolescent. The circumnatal growth cycle attains great velocity, which reaches a maximum at the time of birth. The curve of this cycle is best fitted by a theoretical skew curve of Pearson's Type I. It has a theoretical range of 44 months and a standard deviation of 5.17 months. The modal velocity is 10.2 kilos per year. The adolescent growth cycle has less maximum velocity and greater range in time than the circumnatal cycle. The best fitting theoretical curve is a normal frequency curve ranging over about 10 years with a standard deviation of about 21 months and a modal velocity of 4.5 kilos per year. The two great growth accelerations are superimposed on a residual curve of growth which measures a substratum of growth out of which the accelerations arise. This probably extends from conception to 55 years, on the average. It is characterized by low velocity, averaging about 2 kilos per year from 2 to 12 years. It is interpreted as due to many growth operations coincident or closely blending in time. Our curve shows no third marked period of acceleration at between the 3rd and 6th years. The total growth in weight of the body is the sum of the weight of its constituent organs. In some cases these keep pace with the growth of the body as a whole; great accelerations of body growth are due to great accelerations in growth of the constituent organs. In other cases one of the organs of the body (like the thymus gland) may undergo a change in weight that is not in harmony with that of the body as a whole. The development of the weight in man is the resultant of many more or less elementary growth processes. These result in two special episodes of growth and numerous smaller, blending, growth operations. Hypotheses are suggested as to the basis of the special growth accelerations.
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