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Biomedical subjects

G K Thomas

Publications and source records attributed to G K Thomas.

17 recordsLinked to original sources
PubMed1975

Stenting in experimental laryngeal injuries.

This experimental pilot project studies acute laryngeal injuries in 20 dogs and compares the use of three types of stenting materials with using no stent at all following the production of a "controlled airway deforming injury." Each injury was repaired meticulously using stainless steel wire to immobilize the cartilage separations, and fine catgut to close the mucosal lacerations. Animals were killed after observation for periods of two to six weeks postoperatively. Marked infection, ulceration, and granulation tissue formation were observed in most of the stented animals, with the nonstented animals showing the most complete and uncomplicated healing. In this experimental model, acute laryngeal "fractures" were adequately stabilized by suturing and a stable cartilaginous framework supported the healing intralaryngeal soft tissues. Avoidance of stenting in this animal series appears to decrease infection, ulceration, and granulation tissue formation resulting in improved healing.

Acute Disease↗
PubMed1975

Subglottic enlargement using cartilage-mucosa autograft. A preliminary experimental study.

Subglottic stenosis in the infant currently has no well-accepted surgical correction. Our experimental study was designed to determine the effectiveness of a nasal septal cartilage-mucosa autograft in increasing the subglottic circumference and its effect on subsequent subglottic growth. Six pairs of matched mongrel puppy litter mates were used; one underwent surgery, the other served as a control. The cricoid and first tracheal rings were split anteriorly, and widened 5 mm to accept an autogenous nasal septal cartilage-mucosa graft. All animals were killed after six months of postoperative growth. The autografts appeared to be partially or completely replaced by fibrous tissue but a persistent enlargement in the subglottic airway was found in the animals that underwent surgery, with glottic measurements the same in both groups. Thus, a septal cartilage autograft to the subglottic larynx in puppies appears to result in persistent enlargement of the subglottic area, but produces no interference with subsequent normal laryngeal growth and development.

Animals↗
PubMedDate not supplied

Stability of sulfonamide antibiotics in spiked pig liver tissue during frozen storage.

A bulk portion of homogenized pig liver tissue was spiked at room temperature with 0.2 mg/kg (twice the Australian maximum residue limit) of each of sulfathiazole, sulfachlorpyridazine, sulfadimidine (sulfamethazine), sulfaquinoxaline, and sulfadimethoxine. After subsampling and packaging, selected individual packaged units were tested to confirm homogeneity of the prepared material. The material was stored frozen at -20 degrees C and analyzed in replicate by liquid chromatography on 11 sampling dates over a period of about 6 months. Analytical data were plotted on a log-linear scale and subjected to linear regression on the basis of first-order kinetics for the decay. Storage stabilities (decay half-lives at -20 degrees C) calculated from the mean slope of regression lines were sulfadimethoxine, 567 days; sulfadimidine, 457 days; sulfachlorpyridazine, 312 days; sulfathiazole, 291 days; and sulfaquinoxaline, 271 days. Significant depletion (65% loss) of residue was observed for sulfaquinoxaline during preparation of spiked bulk liver tissue. An extension of the study to measure the storage stability of sulfaquinoxaline under accelerated decay conditions (refrigerator temperature, 4 degrees C) showed it to be relatively unstable, with a decay half-life of 11 days. Results demonstrate the need for both regulatory agencies and testing laboratories to be aware of potential errors associated with improper transport, storage, and handling of tissue samples submitted for antibiotic testing.

Analysis of Variance↗