Anatomic measurements of the anterior and posterior ethmoid arteries in cadaveric heads using endoscopic sinus instrumentation.

The challenges of endoscopic sinus surgery lie in the complexity of the anatomy of the nasal vault and side walls and the proximity to critical structures. Additionally, operating in a three-dimensional space while relying on a two-dimensional image for surgical navigation can be a disorienting task. Successful sinus surgery relies on the surgeon having a clear understanding of the anatomy and relationships within the operative field. We performed a study of 8 adult cadaveric heads to better elucidate the location of the ethmoid arteries in relation to an accessible external landmark, the nasal sill. Sinus endoscopy was performed on the heads to identify and measure the distance from the nasal sill to the anterior and posterior ethmoid arteries. We found that the distance from the nasal sill to the anterior ethmoid artery was approximately 6.0 cm, and the distance to the posterior ethmoid artery was approximately 6.7 cm. The interarterial distance was approximately 1.2 cm. With a better understanding of these vessels, surgeons will be better able to avoid them during surgery and thereby minimize the risk of excessive intraoperative bleeding and perioperative orbital hematoma.

Proton pump inhibitor suppression of calcium absorption presenting as respiratory distress in a patient with bilateral laryngeal paralysis and hypocalcemia.

We report an unusual case of hypocalcemia and respiratory distress related to acid-suppressive therapy. The patient was a 50-year-old woman with bilateral laryngeal paralysis and hypoparythyroidism resulting from a thyroidectomy performed more than 30 years previously. She required large doses of calcium supplementation to maintain a normal calcium level. Her airway had been marginally adequate. A few weeks prior to presentation, she began to experience increasing dyspnea. Examination was suggestive of laryngopharyngeal reflux, and she was started on a therapeutic trial of esomeprazole 40 mg twice daily. Three days later, she presented to the emergency room with airway distress. Laboratory studies indicated that the patient had hypocalcemia. The esomeprazole was discontinued, and she was treated with intravenous calcium; her symptoms resolved. We attribute the airway distress to tetany in synkinetically reinnervated laryngeal adductor muscles. We recommend that acid-suppressive therapy should be used with caution in patients with hypoparathyroidism or hypocalcemia.

A comparison of topical chlorhexidine, ciprofloxacin, and fortified tobramycin/cefazolin in rabbit models of Staphylococcus and Pseudomonas keratitis.

AIMS: Chlorhexidine was evaluated as a potential topical therapy for experimental bacterial keratitis. METHODS: Chlorhexidine (0.01%) was compared to ciprofloxacin (0.3%) and tobramycin (1.36%)/cefazolin (5%) both in vitro and in vivo for the treatment of Staphylococcus aureus and Pseudomonas aeruginosa infections. The minimum inhibitory concentration (MIC) was established for each organism for each antibiotic, using a standardized method. One thousand (1000) colony-forming units (CFU) of S. aureus or P. aeruginosa was intrastromally injected into rabbit cornea. A total of 92 corneas were infected and then treated topically with antibiotics. The control eyes were treated with artificial tears. The rabbits were later sacrificed, and the corneal buttons were harvested. RESULTS: The MIC for chlorhexidine was

Bacitracin: substantiation and elimination of contaminating proteolytic activity and use as an affinity chromatography ligand to purify a siderophore-degrading enzyme.

Bacitracin is a commercial general peptidase inhibitor that may be used to purify proteases. Significant protease contamination of a commercial bacitracin preparation was noted and four procedures were developed to overcome the contamination. Dialysis, gel-filtration chromatography, molecular weight cutoff filters, and heat inactivation were effective, resulting in the diminution or elimination of proteolysis while maintaining the inhibitory effect of bacitracin. Attachment of bacitracin to an affinity chromatography resin did not immobilize a siderophore-degrading enzyme, as has been noted with peptidases. It did, however, result in its partial purification from some of the contaminating proteins originally present.