Adrenergic and cholinergic inputs in preoptic area of rats interact for sleep-wake thermoregulation.

Isolated studies have shown that both norepinephrine and acetylcholine into the medial preoptico-anterior hypothalamic area tonically regulate sleep-wake and body temperature. A possible interaction between these neurotransmitters for the regulation of such functions has been investigated in this study. To study this interaction a combination of either prazosin and carbachol or, scopolamine and methoxamine was injected into the medial preoptico-anterior hypothalamic area and the effect on sleep, wake, and rectal temperature recorded simultaneously. The combination of chemicals were selected based on our previous studies where it was observed that each of the chemicals in a combination had opposite effects. It was observed that injection of the combination expressed a resultant summated effects of individual component chemicals when injected in isolation (observed in previous studies). Because effect of neither of the chemicals in the combination was dominant, the results suggest an interaction and integration of the adrenergic and cholinergic inputs in the medial preoptico-anterior hypothalamic area for the regulation of sleep-wakefulness and body temperature.

Epidemiology of hospitalization for near-drowning.

BACKGROUND: Although drowning is the third leading cause of accidental death among children less than 4 years of age, few studies have described the hospitalization of near-drowning victims. Our study emphasizes the local epidemiology and charges associated with pediatric hospitalization in cases of near-drowning. METHODS: Data regarding time, place, injury severity, circumstances, outcome, and hospital charges were collected by retrospective medical record review. Cross tabulation of datasets with descriptive statistical analysis was done using R:Base System V. RESULTS: Between 1987 and 1991, 53 victims of near-drowning were admitted or transferred to Children's Hospital of Alabama in Birmingham. Thirty-three of the incidents occurred during the months of June, July, and August; 32 occurred in pools, 11 in lakes and rivers, 6 in bathtubs, 3 in mop buckets, and 1 in a cesspool. The mean hospital stay was 8 days (combined total, 439 days), accounting for total charges of $749,507 (mean $14,141). Outcomes included 15 deaths, 5 discharges with neurologic sequelae, and 33 discharges without sequelae. Private insurance covered 31 patients, 7 were Medicaid patients, and 15 had no coverage. CONCLUSION: Near-drowning injuries have high case fatality rates, a high case sequelae rate, and high hospitalization charges.

Role of cholinergic inputs to the medial preoptic area in regulation of sleep-wakefulness and body temperature in freely moving rats.

The medial preoptico-anterior hypothalamic area receives adrenergic as well as cholinergic inputs. Independent studies showed that both these inputs influence sleep, wakefulness and body temperature. The role of the adrenergic inputs was studied earlier. The role of cholinergic inputs is reported here. The cholinergic agonist, carbachol, and antagonist, scopolamine, were injected into this area during the day and the night in freely moving rats and the effects on sleep-wakefulness and body temperature studied. It was observed that carbachol induced wakefulness accompanied by a fall in body temperature while scopolamine induced an opposite effect, i.e. sleep accompanied by an increase in body temperature. This suggested that the cholinergic input into the medial preoptic area is spontaneously active in regulating sleep-wakefulness and body temperature and this regulation is mediated through muscarinic receptors present in this area. The results also suggest that, contrary to the action of adrenergic inputs (which have a dissociated effect on sleep-wakefulness and body temperature), the cholinergic input is unlikely to have a dissociated effect on those functions.

Dystonic reaction following recommended use of a cold syrup.

A healthy 3-year-old boy presented to our emergency department with sudden onset of abnormal movement. This patient had been treated for 2 days with conventional doses of an antihistamine/decongestant cold preparation for upper respiratory infection symptoms. The child was confused and restless, with posturing of limbs. Cranial nerve function was intact. Gastric lavage yielded an aspirate the same color as the cold syrup the child had ingested. A diagnosis of dystonic reaction was made, and the child was treated with benztropine, which effected resolution of his symptoms. This is the first reported case in the literature of dystonia induced by an antihistamine and treated with benztropine.

Avoiding a wrapped endotracheal tube in laser laryngeal surgery: experiences with apneic anesthesia and metal laser-flex endotracheal tubes.

Ninety-one laser laryngeal procedures using the apneic technique of anesthesia were performed in 28 patients between 2 months and 64 years of age. Seventy-two procedures (79%) were performed on children and 19 on adults. There were no complications. Eight laser laryngoscopies were performed using a new metal Laser-Flex endotracheal tube. Obstruction of the endotracheal tube with a mucous plug occurred in one case. The apneic technique described in this paper provides a laser operative field free of an endotracheal tube, virtually eliminating the danger of a laser fire. It is a relatively safe and effective means of performing laser laryngeal surgery. In addition, the Laser-Flex endotracheal tube appears to be an acceptable alternative to a metallic tape-wrapped endotracheal tube.

Role of prolactin and luteinizing hormone in regulating timing of implantation in the spotted skunk.

The western spotted skunk exhibits an obligate delay of implantation lasting 200-220 days. The pituitary is essential for luteal activation. The corpora lutea, in turn, secrete the hormones necessary for blastocyst implantation. Two experiments were designed to determine which pituitary hormones are responsible for increasing luteal activity and induction of implantation. Forty-two pregnant skunks with delayed implanting blastocysts were treated as follows: 13 served as untreated controls, 6 received 0.5 mg prolactin (PRL) daily, and 5 received diluent beginning in January. Four received 1.5 mg bromocriptine (CB-154) daily, 3 received both CB-154 and PRL, 3 received diluent, 5 received a gonadotropin-releasing hormone agonist (GnRHa) dispensed from osmotic minipumps, and 3 received diluent dispensed from osmotic minipumps starting in April. The skunks were subjected to a natural photoperiod. Duration of preimplantation and blood levels of progesterone and luteinizing hormone were measured. PRL significantly (p less than 0.05) shortened and CB-154 significantly (p less than 0.05) prolonged the duration of preimplantation when compared to controls (148 +/- 33.6 vs. 251 +/- 3.2 vs. 199 +/- 5.1 days, respectively). PRL was able to reverse the inhibitory effect of CB-154 when both were administered simultaneously (195 +/- 4.0 vs. 251 +/- 3.2 days). GnRHa had no significant (p greater than 0.05) effect on duration of preimplantation (199 +/- 5.1 days) when compared to controls (203 +/- 3.2 days). These results indicate that PRL is the primary pituitary hormone responsible for increased luteal activity and subsequent blastocyst implantation in the spotted skunk.

Size distribution of ferret luteal cells during pregnancy.

Steroidogenic cells in the corpus luteum of the ferret (Mustela putorius) during early (Days 6 and 13) to midpregnancy (Day 24) were characterized using electron microscopy, immunocytochemical localization of neurophysin, and smears of dispersed cells obtained by dissociating luteal cells with collagenase. The latter were stained for 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) activity, and the diameters of the cells were determined with an ocular micrometer. Very small cells (less than 12 microns) stained negative for 3 beta-HSD, occurred in clumps of 5-50 cells, and were presumed to be primarily endothelial cells. 3 beta-HSD-positive cells covered a wide spectrum of sizes ranging from 14 to 56 microns and did not exist as two discrete populations. The ratio of small (less than 25 microns) to large (greater than 25 microns) cells was 1.86:1.0 on Day 6, with the 17- to 20-microns cell size class predominating. On the day of implantation (Day 13), about 75% of the cells ranged from 26 to 50 microns, with the 29-microns size predominating. By Day 24, the ratio of small-to-large cells had declined to 0.15. Nearly 90% of the cells were in the 26- to 56-microns range, the predominant size being 35 microns. All size classes of luteal cells stained negative for neurophysin on all 3 days of pregnancy studied. Luteal cells obtained on Days 6, 13, and 24 of pregnancy failed to reveal any evidence of mitosis after in vivo or in vitro colchicine treatment. We interpret these results as indicating that the 3 beta-HSD-positive luteal cells of ferrets progressively increase in size as small luteal cells complete their differentiation from granulosa cells and ultimately form larger luteal cells with somewhat different ultrastructural characteristics.

Partial characterization of a luteal factor that induces implantation in the ferret.

This study was designed to test the hypothesis that ferret corpora lutea (CL) secrete a compound that acts in conjunction with progesterone to induce blastocyst implantation and to identify the chemical nature of this compound. CL and the residual ovarian tissue, obtained predominantly on the ninth day of pseudopregnancy, were extracted with 0.05 M phosphate-buffered saline. The extracts were injected into pregnant ferrets that had been ovariectomized on Day 6 of pregnancy and had received Silastic implants containing progesterone. Aqueous luteal extracts, but not those of the residual ovarian tissue, induced implantation in test animals. Fractionation of the luteal extracts by passage through a series of filters with molecular weight (MW) cutoffs ranging from 500 to 50,000 consistently revealed that the biologically active fraction was retained on the filter with the highest MW cutoff employed. Moreover, blastocyst implantation failed to occur in ovariectomized, progesterone-treated ferrets after one-half of a luteal preparation (MW greater than 50,000) was incubated with a broad-spectrum protease. These data are consistent with the hypothesis that CL of the ferret secrete a protein during the preimplantation period that is essential for blastocyst implantation.