A developmental and component analysis of active sleep

A wide variety of hypotheses have been put forth that address the functional significance of active sleep. Despite the well-accepted fact that active sleep expresses itself predominantly in the perinatal period, the vast majority of these functional hypotheses are applicable largely, if not exclusively, to the adult. We build on the developmental approaches of previous researchers and propose that the individual components of active sleep (e.g., myoclonic twitches, rapid eye movements) exhibit unique developmental and phylogenetic histories and may serve independent functions in the developing organism. This dynamic perspective leads to specific experimental approaches aimed at the developmental roles of these components in the neonate, their maintenance roles in the adult, and the means by which these various components coalesce temporally in what is commonly referred to as a behavioral state. © 1996 John Wiley & Sons, Inc.     

Prevalence of Candida spp., xerostomia,and hyposalivation in oral lichen planus – A controlled study

Objective

To determine the frequency of Candida spp., xerostomia, and salivary flow rate (SFR) in three different groups: patients with OLP (OLP group), patients with oral mucosal lesions other than OLP (non‐OLP group), and subjects without oral mucosal lesions (control group).

Material and methods

Xerostomia as well as SFR was investigated in the three groups. Samples for isolation of Candida spp. were collected from OLP lesions (38 patients), non‐OLP lesions (28 patients), and healthy subjects (32 subjects).

Results

There was no statistically significant difference regarding the frequency of xerostomia and hyposalivation among the three groups (P > 0.05). A higher prevalence for colonization by Candida spp. was found in the healthy subject as compared to that of patients with OLP (P = 0.03) and non‐OLP (P = 0.02) groups. Low SFR was not a factor for colonization by Candida spp.

Conclusions

Xerostomia and hyposalivation occur with similar frequency in subjects with and without oral lesions; also, the presence of oral lesions does not increase the susceptibility to colonization by Candida spp. It seems that any study implicating Candida spp. in the malignant transformation of oral lesions should be carried out mostly on a biochemical basis, that is, by testing the capability of Candida spp. to produce carcinogenic enzyme.     

Laryngeal histoplasmosis

Histoplasma capsulatum is an endemic fungus found in moist, fertile soil; in North America, it is most prevalent in the river valleys of the central United States. Most primary infections in the immunocompetent host are asymptomatic or are thought to be a flu-like illness. Disseminated histoplasmosis most commonly occurs in immunosuppressed patients. Histoplasmosis infection involving the larynx is an extremely rare manifestation. Here, we describe the case of an immunocompetent man with symptomatic, acute pulmonary histoplasmosis with laryngeal involvement who presented with a chief complaint of hoarseness. We also review the literature of immunocompetent patients with laryngeal histoplasmosis.     

Vanilloid receptor loss in rat sensory ganglia associated with long term desensitization to resiniferatoxin.

A dose-dependent loss of vanilloid receptors (specific [3H]resiniferatoxin binding sites) was found in sensory ganglia of rats 24 h after s.c. administration of resiniferatoxin (RTX), an ultrapotent capsaicin analog. This receptor loss displayed an ED50 of 30 micrograms/kg both in dorsal root and trigeminal ganglia; the ED50 was 6-fold higher than the ED50 for loss of the neurogenic inflammatory response and 30-60-fold higher than the ED50 for desensitization in the standard eye-wiping (chemogenic pain) response. The receptor loss appeared later (24 h) than the loss of the physiological responses (6 h) and showed modest recovery (to 20-30% of control levels) over the following 4 weeks. This vanilloid receptor loss may represent a novel, specific mechanism for vanilloid-induced chronic desensitization.     

Effects of antihypertensive drugs on ultrasound production and cardiovascular responses in 15-day-old rats

When exposed to extreme cold or injected with the alpha(2)-adrenoceptor agonist, clonidine, infant rats emit ultrasonic vocalizations (USVs). Based upon the cardiovascular changes that accompany these two manipulations, especially decreased venous return, it was hypothesized that USVs are the acoustic by-product of the abdominal compression reaction (ACR), a maneuver that increases venous return. If this hypothesis is correct, then other anithypertensive drugs that decrease venous return should evoke USVs. In Experiment 1, sodium nitroprusside (SNP, 400 microg/kg), a direct-acting dilator of arteries and veins, was administered to 15-day-old rats under thermoneutral conditions while cardiac rate and ultrasound production were monitored. In Experiment 2, femoral artery pressure was monitored after SNP administration. Infants responded to SNP administration with decreased arterial pressure and tachycardia and, in addition, significantly increased ultrasound production. In Experiment 3, chlorisondamine (5 mg/kg), a ganglionic blocker that causes vasodilation and bradycardia, and hydralazine (20 mg/kg), a selective dilator of arteries, was administered to 15-day-olds. As predicted, chlorisondamine evoked ultrasound production and hydralazine did not. These results introduce SNP and chlorisondamine as only the second and third known agents capable of independently evoking USVs in thermoneutral conditions, and provide further support for the notion that ultrasound production is triggered by decreased venous return.