Performance of the plant-based repellent TT-4302 against mosquitoes in the laboratory and field and comparative efficacy to 16 mosquito repellents against Aedes aegypti (Diptera: Culicidae).

Repellent efficacy of the plant-based repellent, TT-4302 (5% geraniol), was compared with 16 other products in laboratory arm-in-cage trials against Aedes aegypti (L). Eight repellents (Badger, BioUD, Burt's bees, California Baby, Cutter Natural, EcoSMART, Herbal Armor, and SkinSmart) exhibited a mean repellency below 90% to Ae. aegypti at 0.5 h after application. Three repellents (Buzz Away Extreme, Cutter Advanced, and OFF! Botanicals lotion) fell below 90% repellency 1.5 h after application. TT-4302 exhibited 94.7% repellency 5 h posttreatment, which was a longer duration than any of the other repellents tested. The positive control, 15% DEET (OFF! Active), was repellent for 3 h before activity dropped below 90%. Additional arm-in-cage trials comparing TT-4302 with 15% DEET were carried out against Anopheles quadrimaculatus Say. At 6 h after treatment, TT-4302 provided 95.2% repellency while DEET exhibited 72.2%. In North Carolina field trials, TT-4302 provided 100% repellency 5 h after application against Aedes albopictus Skuse while DEET provided 77.6% repellency. These results demonstrate that TT-4302 is an efficacious plant-based repellent that provides an extended duration of protection compared with many other commercially available products.

Activity of the plant-based repellent, TT-4302 against the ticks Amblyomma americanum, Dermacentor variabilis, Ixodes scapularis and Rhipicephalus sanguineus (Acari: Ixodidae).

The plant-based repellent TT-4302 (5 % geraniol) was compared to deet (15 %) in laboratory two-choice bioassays against the ticks Amblyomma americanum, Dermacentor variabilis, Ixodes scapularis, and Rhipicephalus sanguineus. At 2.5 and 3.5 h after treatment of filter paper with TT-4302, 100 % repellency was observed for all species at both time points with the exception of I. scapularis at the 3.5 h evaluation where repellency was 95.8 %. Deet was 100 % repellent at both time points for D. variabilis and R. sanguineus and was 100 % repellent at the 2.5 h evaluation for I. scapularis. Repellency of deet to A. americanum was 88.9 and 95.8 % at 2.5 and 3.5 h, respectively which was not significantly different than that of TT-4302. No significant difference against I. scapularis was observed between TT-4302 and deet at 3.5 h after treatment where deet was 87.5 % repellent. A variant of TT-4302, TT-4228 was tested in the laboratory against A. americanum and was compared to deet (15 %) in field trials against wild populations of ticks in North Carolina, USA. In the laboratory, TT-4228 was 94.4 and 87.5 % repellent at 2.5 and 3.5 h after treatment, respectively. In the field where the predominant tick species was A. americanum, significantly fewer ticks were collected from socks worn by human volunteers that were treated with TT-4228 compared to those treated with deet 2.5 or 3.5 h after treatment. Significantly fewer ticks were recovered from socks treated with TT-4228 than their paired untreated controls 2.5 or 3.5 h after treatment and repellencies were 90 and 70 %, respectively. Fewer ticks were collected from deet-treated compared to their paired untreated socks 2.5 h after application; however, no significant difference was found in the number of ticks collected from deet-and untreated socks 3.5 h after treatment.

Life-threatening presentations of fibrovascular esophageal and hypopharyngeal polyps.

Giant fibrovascular polyps of the esophagus and hypopharynx are benign tumors of the upper digestive tract. Although a rare cause of asphyxiation, laryngeal impaction by a regurgitated polyp of the esophagus may be the initial symptom that brings the patient to request medical attention. Two new cases of giant fibrovascular polyps with dramatic and potentially life-threatening presentations illustrate the unpredictable behavior of these unusual tumors. Both patients presented to the emergency center with a history of coughing and eructation followed by temporary airway obstruction that was relieved by clenching a regurgitated fleshy mass between the teeth. Diagnostic and therapeutic intervention requires aggressive airway management, radiographic and endoscopic evaluation, and definitive surgical treatment. Tracheotomy was required in one patient, and successful endotracheal intubation provided satisfactory airway control in the second. Esophagoscopy revealed the origin of both tumors to be near the cricopharyngeal muscle. Complete surgical excision was curative in both cases.

Otoacoustic emissions in children with normal ears, middle ear dysfunction, and ventilating tubes.

The clinical utility of otoacoustic emissions (OAEs) has been well established in adults. The purpose of this investigation was to determine the efficacy of OAE testing in children. Distortion-product OAE (DPOAE) audiograms, response/growth functions, and transiently evoked OAEs elicited with clicks were measured from the ears of both healthy volunteers, aged 4 to 13 years, and children with confirmed middle ear disorders. These measures established the means and variabilities for DPOAE and noise-floor amplitudes of normal and diseased young ears. Compared with adult emissions, the healthy young ears exhibited greater mean DPOAE and noise-floor amplitudes. In contrast, ears with type B and type C tympanogram patterns showed absent or markedly reduced OAE amplitudes, when compared with emissions measured in their control counterparts. Finally, ears with ventilating tubes exhibited OAE amplitudes lower than amplitudes from healthy ears, but higher than those of the untreated diseased ears. Although these findings imply that using OAEs to test the outer hair-cell reserve of infected ears is problematic, emitted responses provide useful information concerning the normalcy of middle ear function.

cis-platinum ototoxicity in children.

Despite the recognized ototoxicity of cis-platinum, a clinical outline for the audiologic evaluation of patients receiving this drug has not been clearly defined. In a practical approach to this problem, the audiograms of 48 pediatric patients referred for monitoring during planned cis-platinum therapy were reviewed. Eleven patients tested with auditory brain-stem response (ABR) audiometry demonstrated several limitations of this modality. Fourteen children underwent initial ABR testing followed by at least two pure-tone audiograms. The remaining 23 patients had their hearing evaluated by pure-tone audiometry only. Various factors such as patient age, cis-platinum dosage, and cranial radiation exposure were analyzed for apparent effect. Younger patients tended to be more susceptible to audiologic changes with the administration of cis-platinum. The proportion of patients who demonstrated a hearing loss increased with successive dosing as did the severity of the hearing loss. Prior exposure to cranial radiation was strongly linked to the development of hearing loss following cis-platinum therapy. Guidelines are presented regarding the use of clinical audiometry in the screening of these pediatric oncology patients.

Treatment of peritonsillar abscess. A prospective study of aspiration vs incision and drainage.

A prospective clinical study was performed on 62 patients with peritonsillar abscesses at Ben Taub General Hospital, Houston. The abscesses were treated with either incision and drainage or needle aspiration alone. The recovery period was similar in both groups, but two of the 41 patients initially treated with aspiration had an immediate recurrence. These were successfully treated with subsequent incision and drainage. The advantages of needle aspiration alone as the primary drainage procedure outweigh the acceptably low failure rate, making it the initial procedure of choice.

Central and peripheral hemodynamics during maximal leg extension exercise.

The purpose of this study was to examine the central and peripheral hemodynamic adaptations to maximal leg extension exercise. Seventeen men (X = 25 years, 84 kg) performed leg extension exercise (Universal equipment) for 12 repetitions (90s) to fatigue. Each repetition consisted of a 3s lifting motion, 1s pause, and 3s lowering motion. Impedance cardiography was used to measure stroke volume (SV), cardiac output (Q), systolic time intervals, and impedance contractility indices on a beat-by-beat basis. There were significant increases in systolic, diastolic, mean arterial pressure, total peripheral resistance, and HR during exercise. The mean Q remained similar throughout the protocol. SV decreased even though indices of myocardial performance indicated an enhancement of contractility. The magnitude of Q and SV were dependent upon the phase of leg extension. SV and Q during the lifting portions of the exercise were smaller than the lowering portions. The differences in SV and Q during the concentric and eccentric phases of the exercise most likely reflect the large static forces in exercising muscle which impeded venous return and increased afterload.