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The circadian pattern of melatonin and cortisol secretion was evaluated in two groups of elderly subjects (aged 66-90 years), one with Alzheimer's type of multiinfarct dementia (n = 27) and the other without cognitive impairment (n = 16); 13 clinically healthy women aged 20 to 30 years were chosen as controls. All demented patients had severe mental impairment, corresponding to stage 6 of the Global Deterioration Scale. All subjects, either young or aged, were studied as in-patients and were well synchronized with respect to meal timing, diurnal activity and nocturnal rest. At the population mean cosinor analysis (Halberg, 1969) both melatonin and cortisol circadian rhythms reached statistical significance in the three groups of subjects. However, the melatonin circadian profile was clearly flattened in the two groups of elderly subjects by comparison with young controls, due to the selective impairment of melatonin nocturnal secretion. In both elderly groups, but particularly in demented patients, plasma cortisol levels were significantly higher by comparison to young controls, particularly at evening and night time. A significant direct relationship linked the subjects' age and the nadir values of plasma cortisol. Furthermore, the sensitivity of the hypothalamo-pituitary-adrenal axis to dexamethasone (DXM) suppression test (1 mg orally at 2300) was significantly reduced in both elderly groups, and especially in old demented patients, by comparison with young controls. Finally, plasma cortisol response to pulse i.v. injection of a small dose of synthetic corticotropin (Synacthen 2,500 ng) was significantly higher and more prolonged in old demented patients than in mentally healthy old subjects and in young controls.(ABSTRACT TRUNCATED AT 250 WORDS)

The cosinor method was used to study the circadian variations in 36 haematic parameters in apparently healthy elderly subjects. A nyctohemeral cycle was evident in most cases. Differences in the means and range of IgA, IgG and antithrombin III rhythms compared to those of younger adults were noted. On the whole, the circadian system of the elderly is very similar to that of adults.

In elderly persons a circadian rhythm for total cholesterol, HDL-cholesterol, beta-lipoproteins and triglycerides was observed. The other lipidic fraction do not have any evident circadian rhythm, although Apo-A has a statistical probability near the standard significance level for cosinor method. With exception of triglycerides, the amplitude of the rhythm is small.

A circadian rhythm for beta-endorphin was observed by means of the cosinor method in aged subjects. The rhythm mesor is a little lower but its amplitude is more extended than in young subjects. The confidence intervals of the acrophases of the two groups are superimposable with a timing in the morning.

The problem of the alcohol induced hyperlipemia in men is still in discussion. The Authors have tested the plasma lipid values of elderly subjects, known as a "good drinkers" in relation to abstemious males of equal age. No significant differences were found in the plasma lipid values of the good drinkers compared with those of the abstemious patients.

In 8 young and 8 elderly subjects mean values of plasma beta-endorphin were nearly equal under basal conditions. In all subjects the cold pressor test provoked a marked increase of beta-endorphin, which was more evident in young subjects. Mean values of the areas of endorphin modifications were the same in both young and elderly subjects. These results may suggest that after a short-term stimulus, such as the cold pressor test, no marked differences in pituitary secretion between young and elderly subjects may be evidenced.

The chronobiological analysis by means of the cosinor method on the dynamic electrocardiographic tracings of 30 subjects aged over 65 years with no clinical or instrumental signs of heart disease revealed a significant circadian rhythm of heart rate with acrophase in the early afternoon. When compared with a group of 30 young adult subjects, the elderly exhibited only a non-significant reduction of the rhythm amplitude. Elderly patients with heart disease exhibited a similar chronobiological pattern of heart rate. Premature ventricular beats (PVBs) were present in all subjects and occurred mostly during the day. A significant circadian rhythm was present only in elderly heart patients with 30-150 PVBs/h. The circadian distribution of PVBs showed significant interindividual differences with nocturnal acrophase in about one third of the patients. The chronobiological analysis can represent the basis for a more appropriate therapeutic approach to the elderly with PVBs.

The level of serum ferritin of 226 selected subjects, aged 20 to 93, showed an age-related tendency to rise and in every age studied it was higher in males than in females. This finding is considered to be a consequence of the activation of the reticuloendothelial system and of the increase of iron storage with ageing.

In 12 aged nondiabetic subjects, 10 aged diabetic subjects, and 6 young nondiabetic subjects the glucose, insulin, glucagon and growth hormone responses to the intravenous administration of arginine were studied. A prompt increase in the levels of blood glucose, serum insulin and serum glucagon was observed, but the glucose and glucagon peaks were significantly higher in the aged nondiabetic and diabetic subjects. Growth hormone secretion did not differ between the nondiabetic aged and young subjects. These findings suggest the hypothesis that glucose intolerance in old age is due to increased release of glucagon.

Chronobiological modifications in advanced age were already observed for several biochemical parameters and biological functions. Within a review about the circadian rhythms of some blood constituents in the aged, personal results about blood picture, antithrombin III, serum iron and transferrin, immunoglobulins and some enzymes are reported. A circadian rhythm was evident for almost all parameters considered. Differences with respect to young persons were evidenced for IgA, IgG and antithrombin III. The circadian system in the aged is, in general, similar to that of the adult in the middle life.

In a group of aged nondiabetic and diabetic subjects and in a group of young subjects the glycemic, insulin, growth hormone and glucagon response to intravenous arginine was studied. A prompt increase in blood glucose, serum insulin and glucagon levels was observed, but glucose and glucagon peaks were significantly higher in older non diabetic and diabetic subjects. Growth hormone secretion did not show any difference between aged nondiabetic and young subjects, on the contrary it is lower in diabetics. These findings might suggest the hypothesis of the glucose intolerance during old age due to increased release of glucagon.

The Authors for a better knowledge of the senile kidney have studied the urinary proteins of a group of elderly people resident in a geriatric institute. For instance they have noted the percentage of proteinuria in the urine of 313 patients (M and F) with various pathology, making also an electrophoresis of the urinary proteins. They put in evidence that the subjects with proteinuria were older than others, without proteinuria, and noted the high incidence of the infectious diseases of the urinary tract in these patients. In a second time the urine of 247 apparently healthy elderly people has been studied. Through an accurate examination (that is comprehensive of some serum parameters and a comparison with subjects without proteinuria) the Authors discussed a way of growing old defined "with biological trouble".