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Biomedical subjects

T J Gal

Publications and source records attributed to T J Gal.

At least 19 recordsLinked to original sources
PubMed2000

Radiation effects on osteoblasts in vitro: a potential role in osteoradionecrosis.

OBJECTIVE: To evaluate the factors involved in bone remodeling and wound healing that may be altered by radiation therapy. DESIGN: A prospective, controlled study of biochemical activity in vitro. SUBJECTS: MC3T3-E1 mouse osteoblasts. INTERVENTIONS: Cells were irradiated at 0, 2, 4, or 6 Gy. Specimens were harvested at 1, 7, 14, 28, and 42 days following irradiation for immunohistochemical analysis of transforming growth factor beta(1) expression and transforming growth factor beta(1) type I and II receptor expression. Collagen production was measured at 1, 7, 28, 35, and 49 days after irradiation. The effects of dexamethasone on collagen production and cell proliferation were also examined. RESULTS: Irradiated cells demonstrated decreased cell proliferation and a dose-dependent, sustained reduction in collagen production when compared with control cells. An increase in transforming growth factor beta(1) type I and II receptor expression was noted in irradiated cells when compared with controls. CONCLUSION: Radiation-induced alterations of factors related to bone remodeling and wound healing have a potential role in the pathogenesis of osteoradionecrosis.

Animals↗
PubMed2000

Factors affecting survival for floor-of-mouth carcinoma.

OBJECTIVES: The treatment of extensive floor-of-mouth carcinoma has remained a challenging problem for head and neck surgeons. We have reviewed our experience in the surgical management of floor-of-mouth cancer in an attempt to identify factors influencing survival. METHODS: A total of 144 patients with cancer involving the floor of the mouth were treated between March 1988 and November 1995. A retrospective chart review was conducted that captured information including clinical staging, therapeutic modalities, pathologic findings, and patient follow-up. Factors affecting survival were assessed by nonparametric analysis and analysis of variance. RESULTS: There was no statistical significance for the effects of vascular invasion (P = 0.4019), lymphatic invasion (P = 0.3430), bone invasion (P = 0.1548), or positive margins (P = 0.1113) on survival. Extranodal extension and recurrent disease were strongly suggestive of influencing survival but were not statistically significant (P = 0.0650 and P = 0.0504, respectively). Nodal disease significantly affected survival (P = 0.0138) but did not affect recurrence (P = 0.451). CONCLUSION: Mean survival for this cohort was 30.6 months. Positive node status significantly affected mean overall survival in this series, whereas extracapsular disease did not. These data suggest that aggressive surgical management of neck disease is mandated to maximize survival.

Adult↗
PubMed2000

Risk factors associated with hypothyroidism after laryngectomy.

Hypothyroidism is a well-documented complication after treatment of head and neck cancer and is particularly significant among patients undergoing laryngectomy. The objective of this study was the identification of factors associated with the development of hypothyroidism in this population. Records of 136 patients treated with laryngectomy were retrospectively reviewed in an attempt to define a risk factor profile for patients in whom hypothyroidism is most likely to develop after laryngectomy. The Cox proportional hazards model was used to identify factors significantly related to an increased risk for development of hypothyroidism. The actuarial method was used to estimate the period of greatest risk for the development of hypothyroidism. Increased risks were found for patients who were female (P = 0.0049), received preoperative radiation therapy (P = 0.0022), had invasion of the thyroid gland by tumor (P = 0.0003), had presence of cervical metastases (P = 0.0022), and had postoperative fistula (P = 0.0095). From the actuarial method, we estimated that the period of time when patients were at greatest risk for development of hypothyroidism was between 0 and 14 months after surgical intervention. Wound complications were twice as frequent in hypothyroid patients. Perioperative awareness of risk factors associated with the development of hypothyroidism in patients undergoing laryngectomy allows for early recognition and management of hypothyroidism and may reduce the number of complications related to wound healing and fistula.

Aged↗
PubMed1999

Auricular carcinoma with temporal bone invasion: outcome analysis.

Invasion of the temporal bone by cutaneous carcinoma of the auricle and periauricular skin is an ominous prognostic sign. Management includes aggressive resection of cutaneous disease as well as resection of temporal bone to obtain a medial margin. Analysis of data from 21 patients with temporal bone invasion caused by cutaneous malignancy is presented. Overall survival is approximately 63%. Cumulative survival is significantly decreased in patients with squamous cell carcinoma when compared with other invasive malignancies. Univariate and covariate analyses demonstrate that nodal status, positive microscopic soft tissue margins, and persistent perineural disease at the skull base did not significantly affect survival in this series. There is a trend toward increased survival in patients receiving postoperative radiation in this series.

Adult↗
PubMed1999

Assessment of plate use for mandibular reconstruction: has changing technology made a difference?

Reconstruction of mandibular defects with a variety of alloplastic materials during a 22-year period was reviewed. Outcomes were examined to determine whether specific plating technology affected the incidence of plate-related complications including plate exposure, plate fracture, and plate removal. Repair with the miniplate, reconstruction plate, titanium hollow screw reconstruction plate, and locking reconstruction plate was evaluated. Although the incidence of plate fractures has decreased, there was no significant change in the rate of plate exposure. Recurrent disease was noted to be a significant contributing factor in the development of plate-related complications.

Adult↗
PubMed1998

Reconstruction after temporal bone resection.

Reconstruction of soft tissue defects after temporal bone resection can vary from simple closure of the external auditory canal to complex flap coverage of extensive defects. Between 1987 and 1996, 34 patients underwent lateral skull base resections and reconstruction for invasive carcinoma of the temporal bone. Seven underwent sleeve resection and/or radical mastoidectomy. Sleeve resection was managed with tympanoplasty, canalplasty, or obliteration of the external auditory canal (10). There were 24 lateral temporal bone resections and four subtotal temporal bone resections. Larger defects created by lateral and subtotal temporal bone resections required closure with a combination of temporalis flaps and local rotational cutaneous flaps (13). Lower island trapezius flaps (five), free flaps (four), and pectoralis major flaps (two) were also used. Indications and efficacy of each method are discussed, and treatment outcomes are presented.

Adult↗
PubMed1989

Naloxone reversal of buprenorphine-induced respiratory depression.

In a placebo-controlled, single-blind study we evaluated the ability of three large doses of naloxone (1.0, 5.0, and 10 mg) to antagonize the established respiratory-depressant effects of a common analgesic dose of intravenous buprenorphine (0.3 mg/70 kg). This dose of buprenorphine consistently reduced indexes of CO2 responsiveness to about one half of their control values, much like comparable doses of other opioid analgesics. One milligram of naloxone had little effect on this respiratory depression. Both 5 and 10 mg produced consistent reversal, which was more complete with the larger dose. The reversal effect of naloxone did not occur immediately as is characteristic with morphine and other opioids but rather appeared to reach a maximum 3 hours after reversal. These findings indicate that high doses of naloxone are required to antagonize buprenorphine and naloxone's limited efficacy results not from its short duration of action but rather its relative inability to displace buprenorphine already bound to opioid receptors.

Adult↗