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Biomedical subjects

T C Logan

Publications and source records attributed to T C Logan.

12 recordsLinked to original sources
PubMed2000

Effect of stenting after laryngotracheal reconstruction in a subglottic stenosis model.

OBJECTIVES: This study addresses the impact of stenting on early wound healing after laryngotracheal reconstruction (LTR) in a rabbit model with established subglottic stenosis. METHODS: Subglottic stenosis was created in 42 New Zealand white rabbits through a transoral, endoscopic technique. Three weeks later, endoscopy and axial CT were performed to document and grade the degree of stenosis. Subsequently, LTR was performed in all animals, with half of the animals receiving an intraluminal stent. Four rabbits from each group were euthanized on postoperative days 6, 9, 14, 21, and 28. Measurements of graft vascularization were obtained with a computerized image measurement program, and a comparison was made regarding the rate of vascularization. RESULTS: There was a statistically significant increase in the rate of vascularization in the stented group (mean 75% +/- 5% vs 56% +/- 3% at day 14; P < 0. 05). However, clinical and radiographic comparisons of the stented and nonstented specimens revealed a trend toward increased mucosal edema and granulation tissue in the stented group at later time intervals (days 21 and 28). CONCLUSION: This analysis suggests that stenting does not inhibit graft vascularization in the early postoperative period after LTR; however, complications were seen in the stented group at longer time intervals.

Animals↗
PubMed1999

Subglottic stenosis: correlation between computed tomography and bronchoscopy.

The evaluation of subglottic stenosis has been limited by the lack of standardized methods for determining the cross-sectional area and length of the stenotic segment. A rabbit model was used to prospectively evaluate the correlation between computed tomography (CT) and bronchoscopy in the evaluation of this disease. Subglottic stenosis was produced in 39 New Zealand White rabbits by a transoral endoscopic technique. The animals were evaluated 3 weeks later with spiral CT, rigid bronchoscopy, and open laryngotracheal exploration. Spiral CT was performed with the location, degree, and length of subglottic stenosis being determined by a blinded observer. Each animal then underwent rigid bronchoscopy and open laryngotracheal exploration for determination of the same measurements. Data were analyzed to determine the correlation between the radiographic and surgical techniques in evaluating the airway stenosis. With regard to the degree of stenosis, 94% of the rabbits were determined to have CT and bronchoscopic measurements that were within 15% (Pearson correlation .94, p < .05). With regard to the length of stenosis, 94% of animals had a measurement on CT that was within 2 mm of that observed upon open exploration (Pearson correlation .81, p < .05). The CT evaluation of subglottic stenosis correlated well with the currently used method of visual inspection at bronchoscopy in evaluating tracheal stenosis in this animal model. These data suggest that CT could serve as a useful adjunct in the evaluation of tracheal stenosis, especially when serial examinations are required.

Animals↗
PubMed1996

Fibromatosis colli: a common cause of neonatal torticollis.

In infants and children, cervical masses originate from a variety of pathologic, congenital and developmental conditions, and it is important to distinguish benign from serious lesions. Fibromatosis colli is a rare cervical lesion that typically presents in the neonatal period. It is the most common cause of neonatal torticollis and should be recognized by physicians caring for neonates and infants.

Fibroma↗
PubMed1996

Effect of stenting on graft vascularization after laryngotracheoplasty.

The management of pediatric airway stenosis has been an important topic of debate over the last few decades as prolonged intubation has become more common in the neonate. Although many surgical options are available, most would agree that use of expansion techniques (laryngotracheoplasty) with cartilaginous grafting is the procedure of choice for the severely stenotic airway. Controversy persists, however, regarding the role of stents. Advocates feel that stents serve to counteract scar contracture and support the newly constructed airway. In contrast, recent studies suggest that stenting results in impaired wound healing and an increased complication rate. The present study addresses the effect of stenting on the vascularization of cartilaginous grafts in an animal model. Thirty-six New Zealand white rabbits were evaluated after laryngotracheoplasty with autogenous cartilage grafting. Half of the animals were stented with a 2-cm section of an endotracheal tube that was secured just below the glottis. Three rabbits from each group were then painlessly sacrificed on days 4, 6, 8, 10, 14, and 21. Gross and histologic comparisons of the stented and nonstented specimens revealed similar wound healing. Measurements of graft vascularization were obtained with a computerized image measurement program, and a comparison was made regarding the rate of vascularization. There was a statistically significant increase in the rate of vascularization in the stented group (mean 73% versus 55% at day 10; p < .05). This analysis suggests that stenting does not inhibit early wound healing and specifically graft vascularization after laryngotracheoplasty.

Animals↗
PubMed1995

Composite graft survival. An auricular amputation model.

OBJECTIVE: To study the effects of corticosteroids and fibroblast growth factor on composite graft survival using a rabbit model of auricular amputation and reimplantation. DESIGN: Randomized, "blinded," placebo-controlled, prospective animal study. SETTING: Animal laboratory in tertiary care center. INTERVENTION: Amputation of the distal 2 cm of the rabbit ear as a composite graft and reimplantation with simple 6-0 prolene sutures. All animals underwent the same surgical procedure and were randomized into the following four groups: (1) surgical reimplantation alone; (2) 30 mg/kg intramuscular methylprednisolone sodium succinate for 5 days, starting immediately postoperatively; (3) topical basic fibroblast growth factor for 5 days postoperatively; and (4) delayed reimplantation with corticosteroids. In group 4, the ears of the animal were amputated, placed in iced saline containers for 90 minutes, and given 30 mg/kg intramuscular methylprednisolone for 5 days, with the first dose starting immediately prior to reimplantation. MAIN OUTCOME MEASURES: Percentage graft survival and histologic characteristics of viable and nonviable composite graft tissue. RESULTS: The groups that received corticosteroids and delayed reimplantation with corticosteroids had a statistically significant increase in percentage of graft survival compared with the control group (P < .003 and P < .006, respectively). The growth factor group showed no significant difference from the control group. CONCLUSION: Neovascularization occurred in the viable grafts, thus suggesting its role in graft survival. This study establishes the efficacy of corticosteroids in enhancing composite graft survival.

Administration, Cutaneous↗
PubMed1995

The influence of arterial insufficiency and venous congestion on composite graft survival.

A rabbit auricular amputation model was used to study the relative effects of arterial insufficiency (AI) and venous congestion (VC) on composite graft survival. The percentage of graft survival was significantly greater for the AI group (45.8%) than for the VC group (15.9%) 2 weeks postoperatively. The percentage of graft survival at 3 weeks for the VC, AI, and noligation groups were not statistically different. All three groups were statistically different from the control group, which had both the central artery and vein ligated. The VC group also exhibited significantly more graft edema, as measured by maximal graft thickness, than the other three groups. The impact of AI and VC on composite graft survival is investigated and discussed. These results suggest that venous congestion is more detrimental to early graft survival than arterial insufficiency.

Animals↗
PubMed1992

Results following treatment of traumatic dislocations of the knee joint.

In a retrospective study, 31 patients were identified over a period of 25 years as having sustained traumatic knee dislocations without associated fractures. Three patients had early amputation secondary to vascular complications. Ten popliteal artery disruptions and five peroneal nerve palsies were diagnosed. At the time of follow-up evaluation (average, 40 months), 16 patients were examined. Operatively treated patients (n = 6) tended to have better motion (129 degrees) than nonoperatively treated patients (108 degrees). Varus instability was seen in only two patients treated nonoperatively. All patients except one experienced persistent functional limitations. Roentgenographic follow-up examination showed similar degenerative changes in both groups.

Activities of Daily Living↗
PubMed1990

Entorhinal kindling permanently enhances Ca2(+)-dependent L-glutamate release in regio inferior of rat hippocampus.

Rats were kindled to two consecutive class 5 seizures by once-daily entorhinal electrical stimulation. After one stimulus-free month, in vitro Ca2(+)-dependent, K(+)-stimulated endogenous amino acid release was measured in regio superior, regio inferior and dentate gyrus of the hippocampal formation. Ca2(+)-dependent L-glutamate release was robust in all 3 regions of controls and greatest in dentate gyrus; release of GABA and L-aspartate were significant in regio superior and dentate gyrus. L-Glutamate release was significantly enhanced in ipsilateral regio inferior of kindled hippocampus and tended to be greater contralaterally. This pattern was not seen in regio superior or dentate gyrus. These studies, in concert with others, suggest that Ca2(+)-dependent L-glutamate release in hippocampus is augmented by entorhinal kindling and that this enhanced release may be primarily from presynaptic granule cell mossy fiber projections.

Amino Acids↗
PubMed1988

Long-term enhancement of K+-evoked release of L-glutamate in entorhinal kindled rats.

Kainic acid- and K+-evoked in vitro release of endogenous amino acids from hippocampal slices were measured in rats kindled by entorhinal electrical stimulation. One month after completion of kindling, K+-evoked release of glutamate from hippocampal slices ipsilateral to the stimulus site was consistently greater than from both the contralateral hippocampus from kindled animals and all hippocampi of electroshock and sham-surgery control groups. Enhanced hippocampal neurotransmitter glutamate release may be involved in the permanent effects of electrical kindling.

Animals↗