China ; Humans ; Root Canal Therapy

Dental Pulp Cavity ; anatomy & histology ; Humans ; Root Canal Preparation ; methods

Dental Pulp Cavity ; abnormalities ; pathology ; Humans ; Root Canal Therapy ; methods

Humans ; Periapical Periodontitis ; diagnosis ; etiology ; therapy ; Root Canal Therapy ; adverse effects

Humans ; Root Canal Obturation

Humans ; Root Canal Therapy ; instrumentation ; methods

This article reviews the resultsof the basic research about epidermal growth factor and its receptor,and the development of the novel drug, EGF eyedrop, that containing chemically synthesised EGF gene,the construction of EGF expression vector, the transformation of the host cells , the purification of the recombinant protein EGF, the preparation of three batches of the EGF product and identification, the preclinical and clinical trials. Relevant studies show that recombinant EGF consisting of 51 amino acids can be secreted into the medium under the control of the α factor leading sequence in the yeast cells.The EGF can accelerate the growth of corneal-limbal epithelial cells and the healing of an alkali burned corneal. The EGF can be used in curing oral cavity ulcer and skin burned wound. And it has the preventive effects on experimental duodenal ulcer of rat. The antiserum was made for test of the con- centration of blood EGF and urine EGF by RIA. Data from studies demonstrate the inhibition effect of EGF on the growth of tumor cells, such as A431 and BT325 cells in the presence of high EGF concentration (＞10 ng/ml). The expression of EGFR and DNA ploidy in renal carcinoma has clinical significance. Crystallization and preliminary x-ray diffraction studies of the EGF has been made. The MW of the EGF product is 6000, and the pI is about 4. 6 and it has correct N-terminal amino acids sequences , immunogenicity and biological activity. There is no vestige of the DNA of the yeast cells. Animal experiments reveal that there is no cumulation of the EGF in the body, and EGF can promote corneal epithelial healing. There is no toxicological effect during cornea wound healing of rabbit. A randomized, double-blind, placebo-controlled, multi-center clinical trial was conducted in four hospitals to assess safety,ocular tolerance and efficacy of an ophthalmic solution of EGF for 200 cases of cornea transplantation and 247 cases of nebulae. Unequivocal results were obtained as the eyedrop really accelerate the wounded cornea healing. So, the EGF eyedrop as a novel drug of class I is approved by the National Drug Administration, and this is the first gene engineering drug that come from yeast expression system in China.

Investigate the cleaning ability of manual ProTaper on mandibular second molars with C-shaped (c-shaped root) or normal root canal(separated root). Twenty mandibular second molars with C-shaped root or with separated roots were sectioned at 3.0, 5.5 and 8.0 mm from the root apex. The images of pre-preparation and F1, F2, and F3-prepapared of manual ProTaper were captured respectively. The cross-sectional areas of the canals were measured and the formula of area after treatment/area before treatment was used to calculate the area ratio. The data were analyzed by SPSS 10.0. The results showed that there was no statistically difference between cross-section root canal area ratios in two groups. Significant differences were found between the cross-section canal area ratio of F1 and F2, F1 and F3 at section 5 mm of S group, and F1 and F3 at section 3 mm of C group. The results suggested that the increasing of cross-section ratio of the two kinds of canals was not obviously concerned with their anatomical morphology.

This study aimed to investigate the expression of Flk-1 on distinct hematopoietic precursor cells in E10.5 mouse AGM region. By flow cytometry, we found that < 10% of Flk-1(+) cells of E10.5 AGM region co-expressed CD41 and CD45/Ter119. Then, E10.5 AGM cells were fractionated into two subsets, the CD31(+)CD45(-)Ter119(-)Flk-1(+)CD41(+) cells (R1, putative immature hematopoietic cells) and the CD31(+)CD45(-)Ter119(-)Flk-1(+)CD41(-) cells (R2, putative endothelial cells), followed by methylcellulose-based CFU-C assay and OP9-based stromal co-culture to examine their myeloid or/and lymphoid potential in vitro. The results showed that only R1 cells could give rise to typical hematopoietic colonies in CFU-C assay. In contrast, after co-cultured with OP9 for 7-9 days, both subsets could generate abundant hematopoietic progenitor cells (CD45(+)c-Kit(+)), myeloid cells (Gr-1(+)/Mac-1(+)), erythroid cells (Ter119(+)), and B lymphocytes (CD19(+)). It is concluded that both maturing CD41(+)CD45(-) hematopoietic percursor cells and homogenic endothelial cells express Flk-1 in E10.5 AGM region. It requires further functional assay in vivo to clarify whether the hematopoietic stem cells (HSCs) and their precursors retain Flk-1 expression at this developmental stage.
Animals ; Cells, Cultured ; Coculture Techniques ; Colony-Forming Units Assay ; Embryo, Mammalian ; cytology ; Endothelial Cells ; cytology ; Female ; Hematopoietic Stem Cells ; cytology ; Male ; Mesonephros ; Mice ; Mice, Inbred C57BL ; Vascular Endothelial Growth Factor Receptor-2 ; metabolism

To analyze hematopoietic kinetics of mouse embryonic aorta-gonad-mesonephros (AGM) region, an in vitro tissue culture method was developed in this study, partly based on previous reports. After 2 days of tissue culture, a significant number of erythro myeloid progenitors, as quantitated by colony forming assay was detected in the AGM region. Moreover, the cells from cultured E10.5 AGM region could generate 10.8 ± 3.5 colony-forming unit in spleen (CFU-S) per tissue on average. Transplantation of cultured E10.5-E11.0 AGM cells resulted in efficient (85.7% repopulated) and long-term (> 4 months) reconstitution of lethally irradiated adult recipients with remarkable chimerism [(51.12 ± 21.17)%]. The multilineage contribution of donor cells was validated by significant engraftment of myeloid and/or lymphoid cells in peripheral blood, bone marrow, spleen and thymus of recipients. Taken together, the tissue culture method can enable us to manipulate the AGM region in vitro, fulfilling a systematic evaluation of developmental kinetics of various hematopoietic precursor cells, particularly HSC, in normal and mutant mid-gestation mouse embryos.
Animals ; Female ; Gonads ; cytology ; Hematopoiesis ; Hematopoietic Stem Cells ; cytology ; Hematopoietic System ; embryology ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Tissue Culture Techniques ; methods