Propranolol, a beta-adrenergic antagonist, retards response to MSH in skin of Anolis carolinensis.

Lacking sympathetic innervation, the skin of A. carolinensis, an iguanid lizard, darkens within minutes in response to circulating melanocyte stimulating hormone (MSH) or beta adrenergic agonists such as epinephrine (EPI). This change is produced by dispersion of melanin from a perinculear position within dermal melanophores into superficial dendritic processes.

Thermal proteinoids as excitability-inducing materials.

The deposition of thermal copolyamino acids on planar lipid membranes causes oscillations and action potentials upon electrical stimulation. Results are reported for compositionally simple thermal copoly(asp,glu) and for a more heterotonic polyamino acid. The data conform to the interference that electrical activity of cellular membranes is due to the polypeptide components, not to the lipid components.

Influence of psoralen on NAT activity and melatonin levels in rat pineal gland during the daily period of darkness.

A single injection of either 5 or 10 mg/kg 8-methoxypsoralen (8-MOP) was given intraperitoneally to male rats at the end of the 14 h light phase (at 2000 h). Two h later (at 2200 h), when the normal nocturnal surge of N-acetyltransferase (NAT) activity and melatonin content in the pineal gland had begun in vehicle-injected controls, mean pineal NAT after the 10 mg/kg 8-MOP was 1.8-fold higher than that after vehicle, though pineal melatonin content did not differ between vehicle- and drug-injected rats.

Nyctohemeral rhythm in melatonin response to isoproterenol in vitro: comparison of rats and Syrian hamsters.

The in vitro response of melatonin synthesis was assessed by incubation of individual whole pineal glands for 4 hr without or with different concentrations of isoproterenol in the medium. Pineals were taken either at the end of the 14-hr light phase (day), or at 6 1/2 hr into the 10-hr dark phase (night) after a 30-min exposure of the animals to light just before sacrifice at night. The response was greater in pineals taken at night than in those taken at the end of the light phase in rats, but was absent at the end of the light phase in Syrian hamsters.

Injections of alpha-melanocyte stimulating hormone affect pineal serotonin, melatonin and N-acetyltransferase activity.

To determine if exogenously administered alpha-melanocyte stimulating hormone (alpha-MSH) affects nighttime pineal N-acetyltransferase activity, pineal levels of 5-hydroxytryptophan, serotonin and melatonin, and plasma prolactin levels, adult male hamsters were injected at 1900 hr (lights out 2000-0600 hr) with two doses of the peptide and killed at 0300 hr. The low dose of alpha-MSH (200 ng) produced a significant fall in pineal serotonin, pineal NAT activity and plasma prolactin values. The high dose of the peptide (20 micrograms) increased circulating prolactin titers and pineal serotonin levels and caused a concomitant decrease in pineal melatonin levels.

Reproductive effects of 6-chloromelatonin implants and/or injections in male and female Syrian hamsters (Mesocricetus auratus).

Adult female hamsters were injected each afternoon for 9 weeks with 2.5, 15 or 25 micrograms of melatonin or 6-chloromelatonin (CM). Each drug resulted in a significant dose-related depression in uterine, ovarian and anterior pituitary gland weights.

A pathological classification of nasal fractures.

The management of nasal fractures has been found by several authors to be inadequate. The reason for this is obscure but may be poor understanding of the pathology of nasal fractures. There is no adequate comprehensive classification of nasal fractures.

Hypothalamic neuroendocrine correlates of cutaneous burn injury in the rat: I. Scanning electron microscopy.

Rats were given a standard scald burn on 60% of the body surface or only a sham burn and were sacrificed at intervals from 6 hr to 14 days later. Serum thyroxine (T4), free thyroxine index (FT4I) and triiodothyronine (T3) were depressed compared to values in respective shams as early as 6 hr post-burn. T4 and FT4I were less depressed on post-burn days (PBD) 2-3 than on PBD 1 and then exhibited a further fall.

Pineal dependence of the Syrian hamster's nocturnal serum melatonin surge.

The usual nocturnal surge of pineal melatonin content was blocked by bilateral superior cervical ganglionectomy in male Syrian hamsters. Ganglionectomy and pinealectomy each prevented the nocturnal rise of serum melatonin concentration seen in control animals. The normal nocturnal surge of circulating melatonin in this species appears to depend on the pineal gland and its sympathetic innervation.

Serum melatonin after a single aqueous subcutaneous injection in Syrian hamsters.

A single injection of 25 micrograms melatonin was given subcutaneously in 0.1 ml saline either at 3 h into the light phase (morning) in female Syrian hamsters or at 1 h before the beginning of the dark phase (evening) in males (L/D 14/10 h). In both cases, the maximal mean serum values seen at 20 min after injection (50 ng/ml) were more than 1,000 times the normal nocturnal melatonin concentration.

Effects of environment on infection in burn patients.

Burn patients in an early cohort (n = 173) treated in an intensive care ward without separate enclosures were compared with a later cohort (n = 213) treated in a renovated unit with separate bed enclosures. The number of patients developing infection was significantly reduced in the late group. Observed mortality was compared with mortality predicted on the basis of burn size and age alone.

Rhythmic melatonin response of the Syrian hamster pineal gland to norepinephrine in vitro and in vivo.

Norepinephrine (NE, 10(-6) M) stimulated melatonin accumulation in the incubation medium of rat (but not Syrian hamster) pineals taken at the end of the light phase. However, NE elevated melatonin accumulation in the medium of pineals taken after 20 min of light exposure of animals of either species at 6 h into the 10-h dark phase. A dose response to 10(-7)-10(-5) M NE was observed in both the medium and pineals upon incubation of pineals taken from rats at 4 h into the light phase and from hamsters after 20 min light exposure at 6 h into the dark phase.

Human melatonin in physiologic and diseased states: neural control of the rhythm.

The human melatonin rhythm is endogenous with a surge of secretion entrained to the dark part of the cycle. Reports show consistent blunting or blockade of this nocturnal surge in the presence of sympathetic neurologic lesions and after administration of beta-adrenergic antagonists. However, there is remarkable resistance to elevation of daytime melatonin secretion by adrenergic agonists and by conditions of general sympathetic hyperactivity.

Reduced serum T4 and T3 and their altered serum binding after burn injury in rats.

Total T4 and T3 concentrations are often suppressed in burned patients. To investigate the significance of such changes, we have characterized serum T4 and T3 after full-thickness scald burns (60% body surface under anesthesia) of 270-gm male Sprague-Dawley rats housed in a light:dark cycle of 14:10 hr. Groups (N = 9-15) of BURN, SHAM (anesthesia, fur clipped, no burn) and CON (controls) were sacrificed on postburn days 8 and 14.

Hormonal changes in burned hamsters.

Burned male Syrian hamsters (burn size 23% of body surface) exhibited reduced total (T4) and free (FT4) serum concentrations, a defect in T4 binding to serum proteins manifested by the T4 dialyzable fraction but not the in vitro T3 charcoal uptake, and reduced serum testosterone concentration. These changes are similar to those noted previously in burned humans. Unlike such patients, burned hamsters did not exhibit reduced serum T3 nor elevated rT3 concentrations in a reproducible manner.

Nonthyroidal control of metabolism after burn injury: possible role of glucagon.

The endocrine basis for control of metabolism in nonthyroidal illness is not yet understood. Burn injury is associated with reduced serum concentrations of thyroid hormones and with resting hypermetabolism. One index of severity is total burn size (TBS, % body surface).

Alterations of mental status and thyroid hormones after thermal injury.

In 16 burn patients, mean values for serum T4 and T3, their T3 uptake-derived free indices (FT4I and FT3I) and dialysis-derived free concentrations (FT4 and FT3) were depressed (all P less than 0.001) compared to respective means in 13 normal subjects. In the patients, the free hormone indices were relatively more depressed below control values than were the free hormone concentrations.

Implantation of pericardial substitutes.

Pericardial substitutes have been shown to decrease the formation of pericardial adhesions. For a pericardial substitute to be properly implanted, it must lie over the heart smoothly without buckling and prevent the accumulation of blood under its surface. The technique we describe prevents buckling of the pericardial substitute and consequently reduces the formation of pericardial adhesions.

Mersilene ribbon closure of the median sternotomy: an improvement over wire closure.

With the increased utilization of median sternotomy in thoracic surgery, some difficulties have arisen with closure of the sternum. This article presents a simple, easy-to-perform method of sternal closure utilizing reinforcement of the sternal halves with a material that is less likely to cut through the sternum and that is readily available.

Pineal-induced depression of free thyroxine in Syrian hamsters.

Blind hamsters had no alteration of the dialyzable fraction of serum thyroxine (T4) but had depressed total and free T4 concentrations compared to controls. Prevention of the effects of blinding by pinealectomy indicates pineal influence on circulating free T4 concentration. Parallel changes in free T4 and the free T4 index indicate adequacy of the index in representing pineal-induced changes in free T4.

Pineal function in burns: melatonin is not a marker for general sympathetic activity.

Burn injury in humans or rats is a model of marked elevation of general sympathetic activity for weeks, manifested in part by increased heart rate, metabolic rate, core temperature, and plasma and urinary catecholamines. Plasma melatonin was sampled at 2-h intervals for 24 h in 9 control subjects and 11 patients with severe burn injury. Daytime melatonin was not different between the groups, but nighttime values were significantly lower in the burn patients.

Resolution of RS-abscisic acid and the separation of abscisic acid metabolites from plant tissue by high-performance liquid chromatography.

Attempts to resolve the enantiomers of racemic abscisic acid (ABA) by high-performance liquid chromatography on a chiral stationary-phase column were unsuccessful. However, reduction of RS-methyl ABA (RS-Me-ABA) with sodium borohydride generates a new chiral centre and one of the two isomeric products, the RS-Me-1',4'-cis-diol of ABA, was separated into its enantiomers by high-performance liquid chromatography on an optically active Pirkle column. High-performance liquid chromatography on a mu Bondapak C18 column separated the metabolites and conjugates of [2-14C]ABA fed to tomato shoots.

Effects of injections and/or chronic implants of melatonin and 5-methoxytryptamine on plasma thyroid hormones in male and female Syrian hamsters.

Plasma thyroid hormone concentrations in male and female Syrian hamsters were evaluated in five experiments after two pineal indoles, melatonin (MEL) and 5-methoxytryptamine (5-MT), were administered as chronic s.c. implants and/or daily afternoon injections.