Study on the counting of Streptococcus mutans, Streptococcus sanguis, Haemophilus actinomycetemcomitans by methyl thiazolyl tetrazolium colorimetric method / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To explore the feasibility of methyl thiazolyl tetrazolium (MTT) colorimetric method and the applied condition for the normal bacteria in the mouth, as Streptococcus mutans (S. mutans), Streptococcus sanguis (S. sanguis), Haemophilus actinomycetemcomitans (H. actinomycetemcomitans).</p><p><b>METHODS</b>Colony forming units (CFU) which was the standard antitheses was used to count bacteria. This study would gain some parameters by changing wavelength, reactive time, dosage and so on. MTT colorimetric method was applied in the counting of S. mutans, S. sanguis and H. actinomycetemcomitans.</p><p><b>RESULTS</b>When counting S. mutans, the best wavelength was 510 nm, the best range was 1.5 x 10(5) - 1.0 x 10(7) CFU x mL(-1). When counting S. sanguis, the best wavelength was 545 nm, the best range was 1.5 x 10(5) - 2.0 x 10(7) CFU x mL(-1). When counting H. actinomycetemcomitans, the best wavelength was 557 nm, the best range was 1.0 x 10(6) - 5.0 x 10(7) CFU x mL(-1). MTT colorimetric method can be used for different aged S. mutans, S. sanguis and H. actinomycetemcomitans.</p><p><b>CONCLUSION</b>Oral bacteria could be counted by MTT colorimetric method, which is fast and convenient.</p>

Effect of Drynaria fortunei naringin on the total protein content and ultra-structure of human periodontal ligament cells / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effects of Drynaria fortunei naringin on the total protein content and ultra-structure of human periodontal ligament cells (hPDLCs).</p><p><b>METHODS</b>Through enzyme digestion combined tissue-culture method, primarily culture and identify the human periodontal ligament cells. Coomassie brilliant blue staining was used to detect the total protein content of hPDLCs with the effects of difference concentration of Drynaria fortunei naringin at difference times. Transmission electron microscope was used to study the ultra-structure of hPDLCs with the effects of Drynaria fortunei naringin.</p><p><b>RESULTS</b>In vitro, the addition of Drynaria fortunei naringin at dose of 100, 10, 1, 0.1 mg x L(-1) in cultures resulted in an increase of total protein content at the 3rd, 5th, 7th day, but the maximum response was obtained with 1 mg x L(-1) Drynaria fortunei naringin. There were more rough endoplasmic reticulums, mitochodrias and ribosomes in the experimental group than in the control.</p><p><b>CONCLUSION</b>Drynaria fortunei naringin may stimulate the protein synthesis and metabolism of hPDLCs.</p>

Effects of Drynaria fortunei naringin on proliferation, alkaline phosphatase activity of human periodontal ligament cells / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the biological effects of Drynaria fortunei naringin on the proliferation and alkaline phosphatase (ALP) activity of human periodontal ligament cells (hPDLC).</p><p><b>METHODS</b>hPDLC were primarily cultured and identified in vitro through enzyme digestion combined tissue culture method. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method was used to observe the proliferation of hPDLC with the effects of different concentrations of Drynaria fortunei naringin at difference times. The method recommended by International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) was adopted to investigate the effect of Drynaria fortune naringin on the alkaline phosphatase (ALP) activity of hPDLC. At the same time, we used bright blue method to detect the contents of protein in each sample. Then ALP activity in per milligram protein was accounted.</p><p><b>RESULTS</b>Significant proliferative promotion to hPDLC by Drynaria fortunei naringin could be observed at the dose of 10, 1, 0.1 mg x L(-1). Significant ALP activity of hPDLC promotion of Drynaria fortune naringin could be observed at the dose of 100, 10, 1, 0.1 mg x L(-1) and the dose of 1 mg x L(-1) Drynaria fortune naringin had greatest promotion on ALP activity of hPDLC.</p><p><b>CONCLUSION</b>Drynaria fortune naringin might significantly promote the proliferation and increase the ALP activity of hPDLC.</p>

Effect of pulsed Nd: YAG laser irradiation on periodontal ligament fibroblast cultures / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of the pulsed Nd: YAG laser irradiation on the survival rate of human penodontal ligament fibroblast (PDLF) at different power and irradiation time settings, and to compare the morphological change of cells before and after irradiation.</p><p><b>METHODS</b>The cells were cultured and placed into the 96-well tissue culture plates. Cells were divided into groups according to the irradiation time (10 s, 20 s, 40 s, 60 s) and the output energy (0.5 W, 1.0 W, 1.5 W, 2.0 W, 2.5 W). After the irradiation, the cell number were counted and the survival rates were calculated. The correlation between the survival rate and irradiation time as well as power output was analyzed.</p><p><b>RESULTS</b>No significant reduction of survival rates were found in 10 s group, as well as in 20 s group with 0.5 W, 1.0 W setting. The increase of the power output and increase of the irradiation time caused significant reduction of cell survival rate (P <0.05). The irradiation time was more relevant to this reduction than the power output.</p><p><b>CONCLUSION</b>It indicates that the laser irradiation may cause damage to PDLF and decrease the cell survival rate. The irradiation time is more related to this effect than the power output.</p>