A feasibility trial of gamma sensory flicker for patients with prodromal Alzheimer's disease.

Introduction: We and collaborators discovered that flickering lights and sound at gamma frequency (40 Hz) reduce Alzheimer's disease (AD) pathology and alter immune cells and signaling in mice. To determine the feasibility of this intervention in humans we tested the safety, tolerability, and daily adherence to extended audiovisual gamma flicker stimulation.

Methods: Ten patients with mild cognitive impairment due to underlying AD received 1-hour daily gamma flicker using audiovisual stimulation for 4 or 8 weeks at home with a delayed start design.

Menopause occurs late in life in the captive chimpanzee (Pan troglodytes).

Menopause in women occurs at mid-life. Chimpanzees, in contrast, continue to display cycles of menstrual bleeding and genital swelling, suggestive of ovulation, until near their maximum life span of about 60 years. Because ovulation was not confirmed hormonally, however, the age at which chimpanzees experience menopause has remained uncertain.

Ovarian aging in squirrel monkeys (Saimiri sciureus).

In female squirrel monkeys (Saimiri sciureus), the reproductive period normally extends from approximately 2.5 years to the mid-teens. In the present study, we examined the age-associated cytological changes in the ovaries of 24 squirrel monkeys ranging in age from newborn to approximately 20 years.

Menopause in nonhuman primates?

A gradual alteration in the mechanisms underlying reproduction and fertility characterizes the aging process in human females. These changes culminate in menopause, conventionally defined as a cessation of menstrual cycles that marks the end of reproductive capacity. In fact, a central and defining event in menopause is the discontinuation of ovulation, which is correlated with a number of structural and functional changes in the reproductive axis.

Menopause in female rhesus monkeys.

Fifteen female rhesus monkeys (Macaca mulatto), ranging in age from 8 to 34 years, were studied for one year to characterize the endocrine and menstrual changes associated with menopause in this species. Five monkeys were premenopausal; these younger monkeys, ages 8-11 years, menstruated and showed cyclic ovarian activity during the 12-month study period, as evidenced by menses and periodic elevations of serum estradiol (E) and luteinizing hormone (LH) concentrations. Four females, ages 24-26 years, were in transition to menopause.

Effects of anesthetic agents on the adrenocortical system of female baboons.

Invasive surgical procedures are often used to study the reproductive and adrenocortical endocrine systems in primates. Anesthetic agents must, therefore, be used that have the least confounding effects on these systems. The present study was designed to characterize various adrenocortical endocrine responses of female baboons (Papio anubis), each treated for 120 minutes with an infusion of ketamine HCl (6 mg/min) in 5% dextrose in water (0.

Effects of age, lactation, and repeated cycles on rhesus monkey copulatory intervals.

Young, sexually mature female rhesus monkeys copulate on more days prior to conception than do older females, and this prolonged discrete mating period is associated with an earlier rise in serum estradiol prior to the first ovulation of the breeding season. The influence of repeated ovulatory cycles and the presence of a suckling infant on the copulatory patterns were examined in two separate analyses. Extending previous work, young, nulliparous females copulated on more days at the first ovulation of the breeding season than did older, multiparous females.

Prenatal ionizing irradiaton and early postnatal growth of Colombian and Bolivian squirrel monkeys (Saimiri sciureus).

Fetal squirrel monkeys of Bolivian and Colombian origin were exposed to 100 rad cobalt-60 radiation in utero and carried to term by the dams. Body weight, head circumference, crown-rump length, and food intake were measured during the first 28 postnatal days. Significant subspecies differences were noted in both mothers and offspring, the Colombian squirrel monkeys being generally larger than the Bolivians.