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Biomedical subjects

G C Park

Publications and source records attributed to G C Park.

9 recordsLinked to original sources

The evaluation of rhytidectomy flap healing after CO2 laser resurfacing in a pig model.

OBJECTIVE: This study was conducted to determine when it becomes safe to perform laser resurfacing after rhytidectomy flap elevation. STUDY DESIGN: Eighty-four sites on 12 domestic Yorkshire pigs were selected; 4 x 10-cm skin flaps were elevated in 72 of the 84 sites and shortened 10%. The 12 remaining sites (controls) were treated with laser resurfacing alone. Laser resurfacing was also performed at days 0, 7, 14, 21, and 28 after closing the skin flaps. The healing time for the laser-resurfaced sites without flap elevation were compared to that of the skin flaps treated with the laser at days 0, 7, 14, 21, and 28. Twelve "skin flap" controls were elevated, shortened 10%, and closed without laser treatment. Resurfacing was performed using 2 passes with the Sharplan Silk Touch CO(2) laser. RESULTS: The average healing time for the skin flaps treated with the laser at day 0 was 23.9 days. All of these flaps showed skin slough with delayed healing followed by scar formation. The areas treated with the laser alone (controls), and the subsequent skin flaps treated with the laser postoperatively at days 7, 14, 21, and 28 days completely re-epithelialized in an average of 7.8, 8.1, 7.3, 7.4, and 7.3 days, respectively. There were no statistically significant differences in healing time between the controls and flaps treated with the laser on or after 7 days (P > 0.05). However, there were statistically significant differences in healing time between the laser-treated skin flaps at day 0 and the controls, between the laser-treated flaps on day 0 and day 7, and between the laser-treated flaps on day 0 and day 14 (P < 0.001). Because there was little difference in healing time after 14 days, only the healing times for laser-treated skin flaps up to 14 days were compared using paired t tests. CONCLUSIONS: From our observations using a pig model, we conclude that skin flaps may be safely laser resurfaced about 1 week postoperatively. On the other hand, simultaneous flap elevation and laser resurfacing results in delayed healing with subsequent scar formation.

Analysis of Variance↗

Merkel cell carcinoma of the lower lip: a case report and histopathologic study.

Merkel cell carcinoma of the lower lip is a rare clinical entity. It is generally thought to be more aggressive than the more common skin cancers of the lips and oral cavity. The literature reveals that delayed diagnoses and poor survival are common among patients with these malignancies. Recommended treatment is surgical excision with wide margins and treatment of cervical metastases with either surgery or radiotherapy or both. Unlike other malignant neoplasms, the occurrence of Merkel cell carcinoma in a relatively older population makes comorbid conditions a key factor in treatment planning.

Aged↗

The role of nitric oxide as an effector of macrophage-mediated cytotoxicity against Trichomonas vaginalis.

The purpose of this study is to determine whether nitric oxide is involved in the extracellular killing of Trichomonas vaginalis by mouse (BALB/c) peritoneal macrophages and RAW264.7 cells activated with LPS or rIFN-gamma and also to observe the effects of various chemicals which affect the production of reactive nitrogen intermediates (RNI) in the cytotoxicity against T. vaginalis. The cytotoxicity was measured by counting the release of [3H]-thymidine from labelled protozoa and NO2- was assayed by Griess reaction. NG-monomethyl-L-arginine (L-NMMA), NG-nitro-L-arginine methyl ester (NAME) and arginase inhibited cytotoxicity to T. vaginalis and nitrite production by activated mouse perioneal macrophages and RAW 264.7 cells. The addition of excess L-arginine competitively restored trichomonacidal activity of macrophages. Exogenous addition of FeSO4 inhibited cytotoxicity to T. vaginalis and nitric products of macrophages. From above results, it is assumed that nitric oxide plays an important role in the host defense mechanism of macrophages against T. vaginalis.

Animals↗