The role of melatonin and serotonin in aging: update.

It has been proposed that aging occurs because of a failure of the pineal gland to produce melatonin from serotonin each day beginning at sunset and throughout the night. This lack leads to a nighttime deficiency of melatonin both absolutely and also relatively to serotonin. As melatonin has wide-spread integrative and regenerative effects, its lack may lead to disturbances normally associated with aging. The present paper reviews the pertinent literature which appeared since our first publication, but earlier articles are also included. Evidence is presented for a role of melatonin and serotonin in controlling the neuroendocrine and immune networks and in inhibiting the development of ischemic heart and Alzheimer's disease, tumor formation and other degenerative processes associated with aging. The possible role of melatonin in the favourable effects of dietary restriction on aging is also discussed. This paper provides additional evidence that a melatonin deficiency, especially in relation to serotonin, may be responsible for the promotion of aging in the organism.

The role of melatonin and serotonin in aging.

The hypothesis presented in this paper defines aging as a pathological process originating in the pineal gland. This results in a diminished output of melatonin, along with a diminished melatonin to serotonin ratio, leading to a decline in adaptive processes and a predictable syndrome manifested by the "diseases of the aged" (DOA) and subsequent death of the organism. That is, aging is a syndrome of relative melatonin deficiency resulting from the gradual failure of the pineal gland.

Simple screening test for significant bacteriuria in urine. Catalase determination by disk flotation method.

Colony count cultures and catalase determinations were done on 294 urine samples in two series of patients at Royal Victoria Hospital. Thirty-six specimens were reported to be positive by colony count and by catalase determination. A total of 135 specimens found to be negative by colony count were also negative by the disk flotation test. Catalase activity in 4 urines reported as false negative were found to contain 6,000 or less colonies per ml. More than 50 per cent of the false positive results could be attributed to the presence of red blood cells. Data were insufficient to explain the remaining false positive catalase determinations. However, catalase determinations by the disk flotation method proved to be a successful screening test for significant bacteriuria.

Cardiovascular effects of levodopa in aged versus younger patients with Parkinson's disease.

The cardiovascular effects of prolonged administration of levodopa were studied in 54 men and women with Parkinson's disease; 23 of them were younger than 70 and 31 were 70 or older. The patients were evaluated clinically before treatment was started and at regular intervals thereafter. The average optimal dosage of levodopa for both age groups was 3.0 and 2.5 gm per day, respectively, during an average treatment period of 20.7 months. Eleven patients showed hypotension (systolic BP of 105 mm Hg or less) that was not related to dosage; in only 6 did the drug have to be permanently discontinued because of syncope; 3 of this group had an associated psychiatric disorder. Four patients had pretreatment hypertension; in 3 the BP fell to normal during therapy; in the remaining patient the hypertension persisted and was successfully treated by an antihypertensive drug. In 5 patients an occasional atrial or ventricular ectopic beat was noted both before and during levodopa therapy but no therapeutic intervention was required. Thirty of the 46 patients with adequate ECG follow-up did not show any significant changes; 5 others showed an increase, and 11 a decrease in myocardial ischemia. Thus the administration of levodopa in elderly patients with or without heart disease is a relatively safe procedure. The only exception would be patients over 70 years of age with a history of previous myocardial infarction. In this group there seems to be a higher incidence of clinically significant hypotension. In such patients, levodopa therapy should be carried out with great caution.

A psychogeriatric assessment program. II. Clinical and laboratory findings.

In a Psycholgeriatric Assessment Program, the statistical evaluation of clinical and laboratory data related to thyroid function in 80 patients led to the conclusion that: 1) differences in thyroid function between psychogeriatric patients of the organic and functional types were only slight, as determined by clinical symptoms and thyroxine blood levels, and 2) factor analysis for 53 selected variables indicated that loading for "gross disturbance of psychobiologic function" may be related to the symptom complex of hyperthyroidism/hyperadrenergism, and particularly to psychobiologic symptoms rather than purely somatic symptoms of hyperthyroidism. In comparison with a group of 60 healthy old people, the psychogeriatric patients showed many more signs of hyperactivity and other characteristics of this symptom complex. The results supported the preliminary impression of an energetic (hyperthyroid-sympathicotonic) reaction to mental decline, accompanied by plasma corticosteroid and electroencephalographic changes.

Biological and psychological predictors of survival in a psychogeriatric population.

Out of 206 geriatric subjects who had been assessed with respect to a number of biological and psychological features (Müller & Grad, 1974), it was possible to reach 180 (or 87%) for a 5-year follow-up. Associations of these previous data to six survival categories were examined in order to explore their prognostic value. Of the biological variables the amount of slow EEG activity showed the greatest predictive power concerning the chances of survival, with only a few subjects, who had shown a slow EEG originally, alive after 5 years. Several other biological variables also showed significant differences between survivors and nonsurvivors; the plasma cortisol levels which were determined after the EEG test were lower in the survivors. Diagnostic and predictive value of routine electroencephalographic examinations in geropsychiatric assessments is emphasized. The close relationship of psychological and biological factors is discussed in the context of a dynamic concept of organic brain syndromes.