Search

In vitro cytotoxicity test is an initial step to identify the harmful effects of new dental materials. Aim of this study was to develop a stable human cell line derived from normal gingival fibroblasts (hNOF) and to assess its feasibility in in vitro cytotoxicity testing. Immortalized human gingival fibroblasts (hTERT-hNOF) were successfully established with human telomerase reverse transcriptase gene transfection, preserving its phenotypical characteristics, replicative potential and biological properties. Utilizing standard cytotoxicity test modeling and dental materials, hTERT-hNOF were evaluated for their feasibility in cytotoxicity testing, compared with hNOF and L929 cells. Similar pattern of cytotoxic response was observed among hNOF, hTERT-hNOF and L929 cells. Cytotoxicity response of hTERT-hNOF was significantly similar to hNOF, moreover hTERT-hNOF and hNOF were found to be more sensitive towards the tested dental materials compared to L929 cells. This study suggested that hTERT-hNOF is an effective cytotoxic test model for dental materials.

We studied renal hemodynamic changes after complete acute unilateral ureteral obstruction in the young lamb.Seven 4-week-old lambs underwent unilateral complete ureteral obstruction and renal blood flow was monitored in both kidneys with ultrasonic flow transducers. Ureteral and arterial blood pressure was measured.In the obstructed kidney renal blood flow was stable for 5 hours and then decreased thereafter to 71% of baseline at 5 days (p0.05). In the contralateral kidney the pattern of renal blood flow constituted a mirror image, although the magnitude of the increase was decreased (122% of baseline at 5 days, not statistically significant). Mean arterial blood pressure did not change in 5 days. Mean ureteral pressure increased from a baseline of 9 to 37 mm. Hg (p0.001) 2 hours after obstruction but gradually decreased to 24 mm. Hg after 24 hours and remained elevated for 5 days (p0.001).The pattern of renal blood flow and ureteral pressure response to obstruction in the young lamb is different from that previously reported. Renal blood flow does not increase after obstruction and it is relatively preserved at 5 days. This unexpected response may be a result of the compound caliceal sheep kidney, immaturity of the young vascular system or development differences in the mechanism of spontaneous decompression of the collecting system.

Acknowledgments This study was supported by the NationalResearch Foundation of South Korea (NRF) funded by the Ministry ofEducation, Science and Technology (2011-0000071) and the NRF(R13-2003-013-04001-0). The authors also would like to extendsincere thanks to Professor Darren Williams, Professor Da-WoonJung and N. Tyagi of Department of Life Science, Gwangju Instituteof Science and Technology, Korea, for critical reading of the manu-script and Professor Ki Yeol Kim of the Oral Cancer ResearchInstitute, Yonsei University College of Dentistry, for the support instatistical data analysis.The online version of the original article can be found underdoi:10.1007/s10856-011-4473-6.R. P. Illeperuma Y. J. Park J. M. Kim J. Y. Bae Z. M. Che H. K. Son J. Kim (&)Department of Oral Pathology, Oral Cancer Research Institute,Yonsei University College of Dentistry, Brain Korea 21 Project,Seoul 120-752, Republic of Koreae-mail: jink@yuhs.acM. R. Han K. M. KimDepartment of Dental Biomaterials, Yonsei University Collegeof Dentistry, Seoul, Republic of Korea

The pathophysiology of fetal urinary obstruction has not been elucidated. Using a unique, reproducible and easily reversible animal preparation, we studied the acute hemodynamic and endocrinological responses to partial fetal bladder obstruction in 16 ovine fetuses at 115 days of gestation (term 147 days). After partial obstruction blood pressure and renal weight increased significantly for at least 72 hours. Renal blood flow trended upwards, particularly from 24 to 72 hours, although this change was not statistically significant. Plasma renin activity was significantly increased during the first 24 hours after obstruction but it returned to baseline thereafter. Plasma cortisol or catecholamine concentrations remained unchanged. The time course and pattern of hemodynamic changes in this fetal sheep preparation of partial urinary obstruction differ significantly from those reported in other preparations.

Histological findings of muscle, collagen and elastin in obstructed fetal bladders were compared with those of age-matched controls. Muscle thickness was markedly increased, however, the relative collagen content in the muscle was decreased. The ratio of thick-to-thin collagen fibers was markedly increased as was the amount of elastin. These findings suggest that the ratio of thick collagen to elastin has an important role in determining the compliance of the obstructed fetal bladder.