Evaluation of a Physical-Chemical Protocol for Porcine Tracheal Decellularization.

INTRODUCTION/OBJECTIVE: Tracheal resection with primary reconstruction is the definitive treatment for many tracheal benign and malignant diseases. When primary resection is not deemed feasible as a result of the length of the stenosis, airway transplantation may become a solution. Tissue engineering offers an alternative way for creating tracheal substitutes. The development of tracheal allograft transplantation includes the decellularized tracheal scaffolds made of extracellular matrix that are seeded with the receptor's cells. Many protocols are used to obtain a decellularized scaffold. Most of them consist of cyclical physical-chemical steps with enzymes. This study proposes a protocol for decellularization based only in physical-chemical steps. METHODS: Decellularization of pig tracheal segments was carried out using a standardized protocol consisting of freezing and thawing, 10 cycles of agitation, exposure to sodium deoxycholate, and washing. The degree of decellularization was determined by quantifying residual DNA. We also analyzed the morphology under hematoxylin and eosin staining. RESULTS: Fourteen porcine tracheal segments were decellularized. All scaffolds obtained showed less than 2% of residual DNA (mean 20 ± 8 ng/mg) when compared to the fresh samples (mean 850 ± 123 ng/mg), P = .001. Morphological analysis showed that the epithelium and mixed glands were completely removed. It was possible to identify residual nuclei inside the cartilaginous rings (73.7 ± 12 × 26 ± 8 nuclei/field, P < .001). CONCLUSION: The protocol tested was able to provide effective decellularization of porcine tracheas.

The control of acute diarrhea in a large industrial plant.

Diarrhea causes considerable absenteeism and loss of working time among employees in the United States. One hundred employees with acute diarrhea at a Ford Motor Company plant were studied for four months to determine if loperamide hydrochloride treatment would control diarrheal symptoms, reduce absenteeism due to the condition, and be well-tolerated. Diarrhea was controlled with a median dosage of three capsules (6 mg total dose) and a range of two to 12 capsules. Ninety-six percent of the subjects were controlled after the first day, 98% by the third day. A statistically significant number were symptom free at their last clinical visits. Side effects were generally minor in nature. Substantially more than 1,000 man-hours of lost time were saved because of the treatment. Known drug dependents did not suffer from CNS effects or "highs". Loperamide acts directly on the intestinal wall to inhibit excessive peristalsis, thereby providing prompt, effective relief, with normal bowel patterns observed in these patients. The simple, individualized dosage is patient-oriented, rather than based on a fixed regimen. Because of its rapid onset of action, effective control of symptoms, low dosage, and being well-tolerated, loperamide meets the criteria for an effective antidiarrheal agent in industry.