Localization of the 110 kDa receptor for laminin in brains of embryonic and postnatal mice.

Laminin, a large glycoprotein of the basement membrane that promotes the growth of nerve cell processes in vitro has also been detected in the brains of developing embryos in situ where it is postulated to promote or guide neural outgrowth. We have investigated the histological and developmental patterns of a receptor to a specific pentapeptide sequence in the A chain of the laminin molecule (PA22-2 or IKVAV) that has been identified as a neuron growth-promoting sequence. Standard immunocytochemical procedures were used to localize the receptor by means of a polyclonal antibody to affinity-purified receptor (MR = 110 kDa) from mouse brains. Results for postnatal stages (P) stages (P 1,7,8,25,30,and adult) show that the 110 kDa receptor is localized in fibers in the cortex and hippocampus, in astroglial cells at the surface of the cortex, and in neuronal cell bodies in the hippocampus. In contrast, the A-chain ligand is localized in cell bodies in the same regions at P stages. For embryonic stages (E) (E 14 and E 16) the receptor is localized in bundles of fibers in the superficial and deep cortical layers, and in cell bodies in these regions at E 14 only. Staining for the A chain ligand of the receptor was first seen postnatally. We speculate that the inverse histological pattern of receptor and ligand with respect to cell bodies and fibers may reflect a role in controlling axon guidance during development or repair during regeneration.

Balloon tracheoplasty in children: results of a 15-year experience.

Strictures of the trachea traditionally have been dilated by antegrade bouginage. This method not only dilates but imparts a shearing force to the wall of the trachea. The resultant trauma may contribute to further scarring and aggravation of the stricture. We report a 15-year experience with 37 patients and 158 tracheal dilatations using balloon catheters that impart only radially directed forces and can be precisely placed and gradually inflated. Various adjunctive techniques have been performed, including: (1) electrocautery of granulation tissue; (2) parenteral and local use of steroids; and (3) intraluminal stenting after dilation. Recent experience indicates that this combination of methods is important in improving patient outcome. The principal indications for balloon tracheoplasty include acquired tracheal stenosis from various causes, and congenital subglottic stenosis. Almost all patients received some immediate benefit from balloon tracheoplasty. Fifty-four percent of the patients achieved long-term improvement (with a minimum follow-up of 2 months). Additionally, 10 of 20 children who had been unable to previously tolerate removal of an indwelling tracheostomy tube proceeded to extubation. We have had poor success in treating bronchial and glottic stenosis. Endoscopically directed hydrostatic balloon tracheoplasty is a safe and effective method for the treatment of tracheal stenosis of varying causes. Multiple dilatations are required that gradually improve the character of the tracheal lumen. In selected cases, the procedure may delay or avoid the need for an open tracheoplasty.

Measurement of average atmospheric temperature using a CO(2) laser radar.

A single-ended CO(2) lidar system has been used to measure the average temperature over a path between the lidar and the foothills located 5 km away. The CO(2) lidar was used to measure the ratio of transmission of the P(38) to the P(20) lines in the 10-microm band of CO(2). This ratio of transmission is directly related to temperature. Good correlation was obtained between the lidar-measured temperature and the thermometermeasured values.