Circadian rhythmicity of ACTH and corticosterone in the rat.

The circadian secretion of ACTH and corticosterone was assessed by measuring immunoreactive ACTH concentration in the plasma and ACTH content in the anterior and posterior pituitary over a 30 h period in groups of both male and female rats and comparing these data to fluorometric corticosterone concentration in the plasma and corticosterone content in the adrenal. A circadian rhythm of plasma corticosterone levels and adrenal content was apparent in both males and females with the highest levels at the onset of darkness. In contrast, there was no significant circadian rhythm in plasma ACTH levels or anterior or posterior ACTH pituitary content.

Hippocampal inhibition of pituitary-adrenocortical function in female rats.

To assess the influence of the hippocampus on ACTH secretion, plasma ACTH concentrations were compared in hippocampectomized and control rats under conditions of differing plasma corticosterone concentrations. In the PM, hippocampectomized rats had higher basal and 2-min ether-stress-induced ACTH concentrations than did cortex-removed controls. Basal PM plasma corticosterone concentrations were also significantly elevated in the hippocampectomized group.

Physiological responses to low-intensity cardiac rehabilitation exercises.

This study determined the oxygen consumption, heart rate, and blood pressure responses in healthy subjects to calisthenic exercises designed for convalescing patients with cardiac problems. Comparisons of the different exercises showed intersubject variability in oxygen consumption per unit of body weight and in cardiovascular responses. The exercises showing the greatest variability in oxygen consumption, however, were not always the exercises with the greatest variability in heart rate and blood pressure.

Prevalence of hyperprolactinemia in anovulatory women.

To determine the prevalence of hyperprolactinemia in an ovulatory patients presenting to a general gynecology clinic, a 1-year prospective study (1978) was instituted. A total of 119 patients with at least 3 months of anovulation were screened with serum prolactin determinations. Those patients demonstrating hyperprolactinemia were further evaluated with a serum TSH level and hypocycloidal polytomography of the pituitary sella.

Emergency evaluation of head injuries in the elderly.

The first hour after head injury in the elderly is the most critical. Airway obstruction and impaired cardiovascular reflex mechanisms are the major initial problems. A patient with an extracerebral hematoma may need emergency trephination.

Acute effects of hypothalamic ablation on plasma thyrotropin and prolactin concentrations in the suckling rat: evidence that early postnatal pituitary-thyroid regulation is independent of hypothalamic control.

Hypothalamic ablation was performed at various periods postnatally in animals previously administered propylthiouracil to raise plasma TSH concentrations. There was no significant change in plasma Tsh up to 8 h after hypothalamic ablation in pups 1--4 days old, whereas hypophysectomy of such pups produced a 60% fall in plasma TSH within 4 h. By the 5th postnatal day, hypothalamic ablation produced a 30% fall in plasma TSH within 4 h (P less than 0.

Current concepts in managing TIAs and stroke.

No permanent neurologic deficit results from a transient ischemic attack, but patients with these episodes are at risk of stroke. Successful treatment depends on identifying the source of the problem--the heart, blood, or vessel wall. However, anticoagulants and antiplatelet agglutinating agents will reduce only the incidence of TIA's, not the incidence of stroke.

Measurement of visual resolution at high luminance levels in patients with possible demyelinating disease.

An interferometric acuity device (Takata) has been used to study visual resolution in individuals with possible demyelinating disease. The instrument employed provides a large field with a continuous range of grid or fringe frequencies and a relatively intense (10(5) mean photopic trolands) stimulus. After a brief period of time with eyes closed, resolution thresholds of patient are repeatedly determined during a five minute period.

Effects of destruction of the suprachiasmatic nuclei on the circadian rhythms in plasma corticosterone, body temperature, feeding and plasma thyrotropin.

To study the role of the suprachiasmatic nuclei (SCN) in generating circadian rhythms in female rats, lesions were placed in the SCN or in the medial preoptic (PO) region. Serial blood sampling at 4-hour intervals at 3 and 13 weeks after surgery indicated that complete SCN destruction abolished rhythmic fluctuation in plasma corticosterone levels in individual rats. Partial destruction produced less interference, while medial PO lesions that spared the SCN were without effect.

Comparison of the effects of deafferentation and ablation of medial basal hypothalamus on thyrotropin and prolactin secretion.

To further delineate the interrelationships of neural control of TSH and prolactin secretion, medial basal hypothalamic deafferentation (MBHD) or medial basal hypothalamic ablation (MBHA) were performed in euthyroid or hypothyroid male rats. MBHD produced a prompt and significant fall in plasma TSH but no change in plasma prolactin. MBHA produced a more marked fall in plasma TSH and a 6-fold rise in plasma prolactin within 3 days postoperatively.

Postnatal development of pituitary-thyroid function in male and female rats: comparison of plasma and thyroid T3 and T4 concentration.

Plasma T4, T3, and TSH, and total and 131l-labeled T4 and T3 in thyroid digests were determined in male and female rats from birth to 30--45 days postnatally. Mothers and offspring were fed a high-iodine Purina diet throughout. In both sexes, plasma T4 was less than 1 microgram/100ml at birth but rose linearly to a peak of 6--7 micrograms/100 ml at day 15.

Lymphoid thyroiditis following immunization with group A streptococcal vaccine.

Severe lymphoid thyroiditis and associated hypothyroidism occurred in all of 7 male and 4 female F(7) derivatives (seventh generation) of rats immunized in each generation against Group A streptococci. This evidence of thyroiditis produced by immunization against a nonthyroidal antigen suggests that some cases of Hashimoto's thyroiditis in humans may result from nonspecific immune responses.

Studies on the site of action of vasopressin in inducing adrenocorticotropin secretion.

Hypophysectomized rats bearing three transplanted pituitaries under the kidney capsule responded to synthetic lysine vasopressin or pitressin with a significant elevation of plasma corticosterone, whereas hypophysectomized rats with no grafts did not. This response was completely abolished by pretreatment of animals with dexamethasone but was unaltered by central hypothalamic destruction. Corticotropin-releasing factor content of the hypothalamic median eminence, hypophyseal stal-, or pars nervosa of the posterior pituitary of intact rats was unchanged 5 or 10 min after ip injection of vasopressin compared to the basal level.

Comparison of pituitary-thyroid maturation in the fetuses of rats fed an iodine-deficient or normal diet.

From the earliest detectable development of fetal pituitary-thyroid function (day 18-19 of gestation) through the first postnatal day, there was a higher degree of stimulation of the pituitary-thyroid axis in the fetuses of rats fed a low iodine diet (LID) than in those of rats fed a high iodine diet (HID). Significant differences between the two groups were consistently observed in relative thyroid size, plasma TSH, 4-h thyroid radioiodine uptake, and the labeled iodoamino acid composition of thyroid digests. Plasma T4 concentration was lower in both LID and HID fetuses and pups than in the HID mothers.

Real-time recording medium: photodichroic KF:LiF.

Laser recording and readout measurements using the photodichroic crystal KF:LiF indicate that the material has potential as an input transducer and an adaptive spatial filter in an optical spectrum analyzer. These crystals are among the most photosensitive recording materials without gain, can be produced in large sizes at relatively low cost, and can be operated close to room temperature using thermoelectric coolers. Experiments using a high precision laser scanner providing 96.