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R C Kern

Publications and source records attributed to R C Kern.

22 records · Page 2Linked to original sources
PubMed1992

Successful in vitro growth of human respiratory epithelium on a tracheal prosthesis.

Reconstruction of tracheal defects may be necessary following trauma or oncologic surgery. Defects up to 8 cm can often be repaired using end-to-end anastomosis. Use of a tracheal prosthesis for larger defects has been complicated by recurrent stenosis and infection. Recent animal studies, utilizing a Dacron polyurethane prosthesis suggest that problems with anastomotic stenosis and infection can be controlled. Problems with a central stenosis within the prosthesis persist when used for defects greater than 6 cm. Establishment of a confluent lining of respiratory epithelium is believed to be necessary for successful prosthetic tracheal reconstruction. Using cell culture techniques, we report the first successful seeding and growth of human respiratory epithelium onto a Dacron polyurethane tracheal prosthesis.

Cell Adhesion↗
PubMed1991

Ultrastructural localization of Na+/K(+)-ATPase in rodent olfactory epithelium.

The olfactory epithelium is comprised of bipolar sensory neurons, sustentacular cells, and basal cells. The sensory neurons have apical knobs and cilia, which project into the olfactory mucus toward the nasal lumen, and represent presumptive sites of odorant binding. Ionic currents, measured across this epithelium in both the resting and odorant-stimulated states, are known to be sustained, at least in part, by active transport of sodium. Information identifying the cellular sites of ion transport in olfactory sensory epithelium will therefore aid in elucidating the ionic mechanisms associated with olfactory transduction. The membrane-bound enzyme Na+/K(+)-ATPase mediates active ion transport in many other cells and tissues. We have consequently employed the cytochemical technique reported by Ernst (J. Histochem. Cytochem., 20 (1972) 23-38, 1322) to identify possible sites of elevated Na+/K(+)-ATPase activity in olfactory epithelium. This procedure detects inorganic phosphate (Pi) released from an artificial substrate (nitrophenyl phosphate) by enzyme catalytic activity. In the presence of strontium ion. Pi is precipitated near regions of high enzymatic activity, then converted to a product visible in the electron microscope. Parallel control preparations were incubated in media (1) supplemented with the specific Na+/K(+)-ATPase inhibitor ouabain (to abolish formation of specific reaction product); (2) with substrate deleted (to demonstrate possible non-specific binding of Sr2+ and/or Pb2+); or (3) with the necessary cofactor K+ deleted. In tissues incubated for demonstration of Na+/K(+)-ATPase activity, reaction product was associated with apical knobs, cilia and dendrites of olfactory receptor neurons at the apical surface. In the more proximal region of the epithelium, reaction product was associated with cell bodies and axons of the sensory neurons, and with the lateral membranes of sustentacular cells. Reaction product was deposited intracellularly, compatible with the known mechanism of the Na+/K(+)-ATPase enzymatic reaction. In control specimens incubated with ouabain, with substrate deleted, or with K+ deleted, only a small quantity of non-specific precipitate was observed. These results are discussed with reference to the various sodium currents implicated in olfactory transduction and transepithelial transport.

Animals↗
PubMedDate not supplied

Efficacy of endoscopic sinus surgery in the management of patients with asthma and chronic sinusitis.

An association between chronic sinusitis and asthma has been noted for many years, although the precise nature of the relationship is poorly understood. Earlier studies, using traditional surgical techniques, have demonstrated subjective improvement in asthmatic complaints. Reports demonstrating improvement following endoscopic sinus surgery for chronic sinusitis are rare. To report our experience with endoscopic sinus surgery and asthmatics, we reviewed the charts of 75 consecutive patients with asthma and chronic sinusitis who underwent endoscopic sinus surgery between 1994 and 1996. Study criteria included the following: chronic sinusitis, one year preoperative and one year postoperative follow-up from endoscopic sinus surgery, and asthma requiring inhaled steroids and oral prednisone for control. Many patients required prednisone bursts for control of asthma. Number of days and total dose of oral prednisone were used as objective measures of asthma control. Number of weeks of antibiotics was used as a relative measure of sinusitis. Fourteen of the 15 patients meeting study criteria decreased their postoperative prednisone requirement by total number of days (preoperative 84 versus postoperative 63 days [p < 0.0001]). Postoperatively, patients required an average of 1300 mg less oral prednisone (p < 0.033). Antibiotic use also decreased, with an average use of antibiotic nine weeks preoperatively versus seven weeks postoperatively (p < 0.045). This study provides corroborative objective evidence that, at least in the short term, endoscopic sinus surgery is efficacious in the management of patients with chronic sinusitis and asthma.

Adolescent↗