No abstract

Annual average indoor 222Rn concentrations in 40 residences in and around Grand Junction, CO, have been measured repeatedly since 1984 using commercial alpha-track monitors (ATM) deployed for successive 12-mo time periods. Data obtained provide a quantitative measure of the year-to-year variations in the annual average Rn concentrations in these structures over this 6-y period. A mean coefficient of variation of 25% was observed for the year-to-year variability of the measurements at 25 sampling stations for which complete data were available. Individual coefficients of variation at the various stations ranged from a low of 7.7% to a high of 51%. The observed mean coefficient of variation includes contributions due to the variability in detector response as well as the true year-to-year variation in the annual average Rn concentrations. Factoring out the contributions from the measured variability in the response of the detectors used, the actual year-to-year variability of the annual average Rn concentrations was approximately 22%.

Background/aim-Isolated stenosis of the lacrimal punctum is a frequent cause of epiphora. Treatment relies on surgical opening or dilatation with bi-or monocanalicular prosthesis. Recently, silicone perforated punctum plugs (PPP) were proposed. The drawback with these silicone PPP was that secretions accumulate in the central orifice blocking the spontaneous flow of tears. A modification of the surface of the PPP using polyvinylpyrrolidone (PVP) was thus proposed. The aim was to compare silicone PPP with new PVP surface treated PPP. Methods-A prospective study was conducted of 20 patients with dilatable stenosis of the lacrimal puncta who developed epiphora. Epiphora, tolerance, implantation of the PPP, and lacrimal drainage were evaluated using scintigraphy of the lacrimal ducts. Results-The raw data and statistical analysis showed evidence of a superior performance of PVP surface treated PPP. Conclusion-Long term evaluation of the advantages or risks of PVP plugs and comparison with microsurgical punctoplasty are warranted.

This investigation was designed to extend our present knowledge of the supraorbital n. (SO n.) distal to the supraorbital notch. It is based on 40 dissected hemi-faces and the position of the notch and the periosteal and frontalis cutaneous branches of the SO n. were studied. The notch was 33.05 mm from the midline on the right side and 30.70 mm on the left. The periosteal branch arises from the lateral frontalis cutaneous branch. Its ascends in an oblique direction laterally and ends in two terminal branches. The frontalis cutaneous branch, after a very short trunk, divides into two branches, medial and lateral. The medial or deep branch enters the corrugator supercilii m. between its fibers. Most frequently, it passes under the inferior fasciculus and superficial to the middle and superior ones. Leaving the corrugator m., it ascends medially into the frontalis m., supplying the median cutaneous frontalis region. The lateral or superficial branch crosses superficial to the corrugator supercilii m. to penetrate the frontalis m. in an ascending and lateral direction, supplying the lateral frontalis region. The two branches enter the frontalis m., displaying a zigzag pattern in order to adapt its length during expressive movements. They cross the frontalis region together with the SO a. and two veins supplying the nerve and the frontalis m. These anatomic data may explain some of the complications after surgery for ptosis and blepharospasm.

The ocular hypotensive activities of the two potent topical carbonic anhydrase inhibitors sezolamide (previously known as MK-417) and dorzolamide (previously known as MK-507 and L-671,152) were compared formulated in Gelrite vehicle, a novel ophthalmic drug delivery system. This was a four-center, double-blind, randomized, placebo-controlled, parallel study in 73 patients with a diagnosis of bilateral primary open-angle glaucoma or ocular hypertension and a morning intraocular pressure (IOP) of greater than 23 mmHg in both eyes following washout of ocular hypotensive medications. Parallel 12-h modified diurnal curves were performed prestudy and on day 6, with a 4-h IOP curve on day 1. On day 6 the peak mean percentage decrease in IOP from baseline occurred 4 h after the dose of dorzolamide (22.1%) and 6 h after the dose of sezolamide (21.3%). There were no significant differences between 2% dorzolamide and 1.8% sezolamide at any time point, although the decrease in IOP for sezolamide tended to be slightly greater than that for dorzolamide. Duration of action of both compounds was, at most, slightly prolonged by the use of Gelrite vehicle when compared with former studies on sezolamide and dorzolamide.