After ending a 4-week period of low-protein diet with or without aminoacetonitrile (AAN), the tail tendons of rats showed an increase of hydroxylysinonorleucine (HLNL) together with other unidentified reducible crosslinks. The binding of dihydroxylysinonorleucine type (DHLNL) was an exception: its content remained unchanged. It may be, assumed, therefore, that the procedures mentioned above act indiscriminately against all reducible crosslinks with the exception of DHLNL. The rise in crosslinks after the 4-week pretreatment was disturbed, when d-penicillamine was given, because it specifically inhibited the formation of HLNL. The content of other crosslink components was slightly increased above that of controls so that the absolute content of total isolated crosslinks increased in the presence of d-penicillamine. No statistically significant differences could be obtained under prednisolone.

Acetonitriles↗

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Lipoprotein profiles and their relation to animal fat intake in healthy old people from four Spanish localities.

In studies carried out on 401 individuals from different Spanish regions, blood lipoprotein levels do not show a clear relationship to amounts of animal fat intake because diet habits change in old age. But in these persons there was a significant and positive correlation between actual LDL levels and animal fat intake when they were 40-45 years old. Similar results are obtained with HDL, but correlations are inversely proportional. Our study leads to the interpretation that diet habits during the first phase of the adult life span are determinant for the lipoprotein profiles in older ages, which can still be observed in very old individuals.

Adult↗

PubMedDate not supplied

Measuring human aging using a two-compartmental mathematical model and the vitality concept.

We calculated a theoretical vitality function as a reference curve, based on experimental results from 226 healthy individuals. This can be used to assess biological aging rates of geographically separate human populations. Only six parameters were used to assess vitality. Each parameter is associated with one of the two physiological compartments. We assume that one compartment keeps the system stable and the other maintains system fidelity. The results permit us to compare vitality curves within populations as well as to determine the age at which maximum vitality appears in each population. The differences between biological and chronological ages in each population and possible etiological interpretations are discussed. This mathematical model can be useful as a method to measure differences in aging rates and effects of aging in several human populations.

Journal Article↗

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Decelerated growth and longevity in men.

Severe dietary restriction delays the physical development of rodents and leads to adult animals of reduced body size but significantly increased life expectancy. We tried to find a similar relationship in human populations using demographical and statistical methods. We show for the total Spanish male population that the mean adult body height reliably reflects the regional living and nutritional conditions. This relation does not only hold for todays socioeconomic data but can also be reproduced using data on family income in the mid 19th century. We calculated the mean height of young men liable to the military service around 1860 and determined their longevity retrospectively using posterior census data. This was done separately for all the Spanish provinces. The linear regression between both parameters manifests a statistically highly significant relationship: the smaller the mean height at age 18 in a province, the higher the chance for people living there to reach high chronological ages. Migrational movements, selection, mortality due to epidemics or unreliability of the population censuses can be largely ruled out as explications for the described correlation. Furthermore, we determined the secular growth trend in Spain for the last 130 years. From 1860 to 1920 the mean height increased by 2.7 cm, from 1920 to 1987 by another 9.8 cm. Since 1950 the trend is above 2 cm per decade country-wide. From 1974 onwards it amounts to 2.89 +/- 0.17. Such high values were worldwide looked upon as isolated cases found only in geographically and socially isolated population subgroups during very limited periods.

Journal Article↗

PubMedDate not supplied

Basic results for assessment of human ageing.

The study of collagen metabolism during the total life span of mammals has contributed greatly to the understanding of the human ageing process. Particularly relevant is the demonstration that these tissue dynamics of collagen in the whole organism is clearly age-dependent, but progresses non-synchronously in different organs. Thus, supply and degradation are tightly linked processes in all tissues, as in the case of other proteins, but the catabolic process regulates the turnover of already deposited collagen in adaptation to local needs. In the whole body there is a similar age-dependent interaction regarding the part of the organism whose activity is directly related with regulating functions mainly supporting the parenchyma, the other part of the organism to work as well as possible. It can be deduced that this regulation attains great importance in ageing because the capacity to survive is dependent on it. At the same time as we expose this dynamical conception of ageing we point out some ageing parameters from experimental gerontology capable of being applied in such a manner as to objectify human ageing manifestations. Furthermore, we propose a way to quantify total ageing on the basis of this interaction, as in a two-compartment system leading to one result which would mean vitality. We discuss related questions, mainly regarding the reference population as control and a good parameter selection which should represent total ageing manifestations in the human body.

Journal Article↗

PubMedDate not supplied

Body surface area as a parameter of age decline.

We determined the age loss of body surface area (DuBois) in a cross-sectional and longitudinal combined study of 209 men and women aged between 40 and 96 from a rural region in the northwest of Spain. We established a secular growth trend of 1.01 +/- 0.30 mm per year, observable in this region since 1880, in 424 men joining the army between 1850 and 1970. Even after consideration of this growth trend, the loss of body surface area was shown to be strongly associated with age in adults of both sexes, with up to 2.5% loss per year in the oldest participants. Similarly the loss of body height becomes an individually dramatic process, in the sense that proportions of the body are no longer preserved. The secular growth trend in this region started long before the improvement of living conditions, commonly cited as causally involved in acceleration processes.

Journal Article↗

PubMedDate not supplied

Estimation of the aging rates of populations through the prevalence of age-related diseases.

Ten prevalences of disease or functional affections due to degenerative processes that statistically show a significant age-dependent behaviour were taken as variables for a biological aging study of a population living in a district of Madrid. The cross-sectional procedure consisted in grouping the disease prevalences by age decades and calculating aging by the vector-analytical mathematical method in which the age-dependent prevalence was the result of one of the total of 10 vector components. The progressive accumulative increase of the vector distances from the origin as well as the distances among the vectors in relation to the population age was considered as biological aging. On the basis of similar mathematical models the results were compared with those obtained from other populations in which different indicators were used; the results are concurrent, but show here a greater aging acceleration than when the population was composed solely of healthy individuals. This is considered a logical consequence due to the sample composition. The presented procedure, focussed epidemiologically, can be useful in comparing aging of populations.

Journal Article↗

PubMedDate not supplied

Increase in insulin secretion with age: its clinical importance in evaluating abnormal secretions focused on diabetes type II and obesity.

The urinary C-peptide excretion was measured in a healthy standardized population sample of 160 subjects from 20 to 90 years of age, homogeneously distributed by age and sex. Urinary C-peptide excretion corresponded to 7% of the total amount released. The daily C-peptide excretion was 61.23 +/- 2.2 (S.E.) microg in the whole sample which corresponds to 41.9 +/- 1.5 IU of insulin secreted/day (I(CP)d), without sex differences. There is an increase of the I(CP)d value from the young to the healthy middle-aged person, but when the results were corrected for standard amounts of excreted creatinine (1 g) and urea (22 g) the age-dependent increase is to be observed during the whole adult life span. Assuming that cross-sectionally observed data are representative of the individual changes, it is concluded that age alone increases insulin secretion. The results which may be useful as reference values for clinical application were as follows: (A) in 5 diabetes type II patients in which the I(CP)d value was measured several times a week, the intraindividual variation coefficient was 10.9 +/- 7.2%;(B) in a sample of 47 type II diabetic patients of both sexes, between 51 and 70 years of age, a clear correlation was found between I(CP)d and the results of the glucagon stimulation test, mainly regarding the relationship between I(CP)d and the planimetrically measured area under the curve (r = 0.7, P < 0.0001); (C) in 7 obese non-diabetic individuals of similar ages the influence of the hypocaloric diet on the I(CP)d value was more evident than the use of C-peptide blood determinations before or after glucagon. Finally, the I(CP)d values of type II diabetes patients with insulin requirement (n = 27) were significantly lower than in the healthy control group (31.1 +/- 24.0 vs. 45.0 +/- 20.4), while diabetic patients without insulin requirement showed significantly higher values (73.0 +/- 33.0) (n = 27). These clinical studies primarily focused on the physiology of human ageing justify the measurement of C-peptide urinary excretion for evaluating daily insulin secretion in patients with type II diabetes.

Journal Article↗