Comparison of two methods of isolation and culture of osteoclasts and the dynamic observation of bone resorption / 北京大学学报(医学版)

Objective: To study the origin, morphological structure, and functional regulation of osteoclast(OC) for further investigation on the mechanism and regulation of bone resorption. Methods: The OCs were isolated by two kinds of traditional method. Osteoclasts were isoclated from neonatal rat long bones. The cytochemistry was observed. The osteoclast-like cells (OLC) were derived from the mouse bone marrow cells in the presence of 1,25(OH)2VitD3 in vitro. Results: Both morphological and functional studies showed that the isolated cells shared some of the typical characteristics of osteoclasts, that is A. multinuclearity; B. developing spreading and pseudopodial activity when cultured on glass; C. high tartrate-resistant acid phosphatase (TRAP); D. resorption lacunae could be found when the cells were cocultured with devitalized bone slices and the number was increased as the time followed. OLC had the same histological and structural traits as the OCs by the former method. The concentration of Ca 2+ and acid phosphatase (ACP) increased gradually. Conclusion: Different kinds of method fit different experiments. The OC obtained by the first method has more activity of bone resorption. The OLC by the second method has more in quantity and can be used in the study of cell differentiation.

Effect of extracellular zinc on osteoclastic resorption in dental mineralized tissues / 北京大学学报(医学版)

Objective:To investigate the bone resorption caused by osteoclasts and modulating functions of zinc ion on dental slices.Methods:Osteoclasts were separated from long-limb bones of neonatal rabbits,cultured with de-activated human tooth slices and glass slices.The cells in the experiment group were treated with 1?10~(-14)mol/L-1?10~(-4)mol/L zinc+10%(volume fraction) fetal calf serum(FCS)+?MEM,while those in the control group were grown in 10%FCS+?MEM.Osteoclasts on glass slices were stained by TRAP staining.The absorption pits on tooth slices were observed by inverted phase contrast microscope.The resorbing activity was evaluated with the concentration of calcium in the supernatant liquid of osteoclasts.The ratio between the concentration of calcium in the experiment group and that of the control group was termed the resorption index.Results: The isolated cells were multinuclear and showed positive in cytoplasma by TRAP staining.Usually,osteoclasts resorbed tooth slices first on the cementum and dentin,which had lower content of mineralized tissue.Compared with those on bone slices,the lacunae on the dental slices appeared less in amount,less in area and shallower in depth.They often showed shallow pits in a large area.Microscopy showed that the number and area of absorption pits formed on treated tissues were less than those on the control tissues.The content of calcium in the supernatant liquid increased at the concentrations of 1?10~(-4)-1?10~(-14)mol/L zinc,especially in the group of 1?10~(-8)mol/L,1?10~(-10) mol/L,1?10~(-14)mol/L zinc on the 3~(rd) day(P

Expression of apoptosis-related protein in epithelial dysplasia and squamous cell carcinoma / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study the expression and significance of apoptosis-related protein p53, Bcl-2, and Bax during the development of oral squamous cell carcinoma (SCC).</p><p><b>METHODS</b>The expression was observed in 10 normal oral epithelia, 48 dysplasia epithelia and 42 SCC by immunohistochemical evaluation.</p><p><b>RESULTS</b>In normal mucosa, the positive rate of p53, Bcl-2 and Bax were 0%, 20% and 60%. In dysplasia epithelia, the positive rate of p53 is increased (P < 0.05), the positive rate of Bcl-2 and Bax remained no significant change (P > 0.05), but the positive intensity in severe dysplasia was higher than in mild group. In SCC, the positive rate of Bcl-2 increased significantly (compared with dysplasia, P < 0.05), while the expression of Bax was decreased with the increase of SCC histological grade. Further analysis showed the correlation was evident in p53 and Bax in dysplasia, and in p53 and Bcl-2 in SCC.</p><p><b>CONCLUSIONS</b>In dysplasia, p53 gene mutation results in accumulation of dysplasia cells. In SCC, the cooperation of p53, Bcl-2 and Bax results in the progression of SCC. Apoptosis genes could work either independently or cooperatively.</p>

Clinicopathological features of unicystic ameloblastoma with special reference to its recurrence / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To clarify the clinicopathological spectrum and biologic behavior of unicystic ameloblastomas (UA).</p><p><b>METHODS</b>Retrospective analysis of 33 UA was undertaken to relate clinicopathological variables to recurrence.</p><p><b>RESULTS</b>The clinical features of this series were in general agreement with that of the previous reports. UA tended to occur at an earlier age (mean 25.3 years), with a male predilection and predominant mandibular involvement (90.9%). Microscopically, the tumors demonstrated a generally monocystic growth pattern, with 8 being simple cystic, 10 comprising intraluminal nodules, and 15 exhibiting a conspicuous component of infiltrative tumor islands in the cyst capsule. Follow-up of 29 patients revealed 6 recurrences with an average interval of 7 years. Recurrence also related to histologic subtypes of UA, with those invading the fibrous wall having a rate of 35.7% but others 6.7%.</p><p><b>CONCLUSIONS</b>Despite the fact that unicystic ameloblastoma may, in general, compare favorably with its solid or multicystic counterpart in terms of clinical behavior and response to treatment, the subsets of the maxillary lesions or tumors exhibiting mural invasion could have a high risk of recurrence.</p>

The crystallographic properties of the mineral phases of enamel and dentin in normal deciduous and permanent teeth / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the crystallographic properties of the mineral phases of normal enamel and dentin (dental apatite) in deciduous and permanent teeth.</p><p><b>METHODS</b>Three kinds of physical methods including X-ray diffraction (XRD), infrared absorption spectroscope (IR) and electron probe micro-analysis (EPMA) were utilized in this study.</p><p><b>RESULTS</b>Dental apatite was not uniphase, but multiphase, which could be described as carbonate-substituted hydroxyapatite. Compared to dentin apatite, the higher crystallinity and expanded a-axis lattice parameters were found in enamel. Chemical analyses demonstrated that higher concentrations of Mg and CO(3)(2-) were found in dentin than those of enamel. But enamel had higher Cl content.</p><p><b>CONCLUSIONS</b>The differences among enamel and dentin, in terms of lattice parameter and crystallinity may be partially attributed to the incorporation of Mg, CO(3)(2-) and Cl minor elements.</p>

In vitro study of the effects of Epimedium on osteoclastic bone resorption in various oral mineralized tissues / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigated the bone resorption caused by osteoclasts and modulating functions of a Chinese herb, Epimedium on bone resorption.</p><p><b>METHODS</b>Osteoclasts were separated from long-limb bones of new born rabbits, cultured with de-activated human tooth slices and glass slices, and treated with different concentrations of Epimedium. Osteoclasts on glass slices were stained by HE staining, TUNEL staining and absorption pits on tooth slices were observed by light microscope.</p><p><b>RESULTS</b>HE staining shows that the Epimedium treated cells showed shrinkage of cytosol and condensation of nuclei. Some treated cells showed breakage of nuclei. TUNEL staining shows that treated cells showed shrinkage of cytosol, dark stained nuclei and light stained cytosol. These results indicate that Epimedium can induce osteoclast to commit apoptosis. Further study shows that the number and area of absorption pits formed on treated tissues are significantly different from those on control tissues. So the effect of Epimedium on bone resorption is dose-dependent.</p><p><b>CONCLUSIONS</b>Epimedium can induce osteoclast apoptosis and inhibit bone resorption. The effect of Epimedium on bone resorption is dose-dependent.</p>

The role of mitogen-activated protein kinase (MAPK) pathway in the action mechanism of PYM-induced KB cells apoptosis / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study the role of mitogen-activated protein kinase (MAPK) pathway in the action mechanism of PYM-induced KB cell apoptosis.</p><p><b>METHODS</b>Western blot analysis was used to investigate the expression of the mitogen-activated protein kinase.</p><p><b>RESULTS</b>When treated with PYM in cultured KB cells, the extracellular signal-regulated kinase (ERKl/2) showed a dose-and time-dependent decreasing in phosphorylation status of these proteins through a western blot analysis, whereas protein levels of p38 MAPK remained unchanged.</p><p><b>CONCLUSIONS</b>The mitogen-activated protein kinase (MAPK) pathway may play an important ro1e in PYM-induced apoptosis of KB cells.</p>

Gene expression of osteoprotegerin and osteoclast differentiation factor in giant cell tumor / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the gene expression of osteoprotegerin (OPG) and osteoclast differentiation factor (ODF/TRANCE/RANKL), two new members of the TNF-receptor superfamily, in giant cell tumor (GCT); to discuss the molecular mechanism of extensive bone resorption caused by GCT.</p><p><b>METHODS</b>Using TRIzol reagent to prepare total RNA from GCT sample and normal bone tissue. By a first-strand complementary DNA (cDNA) synthesis kit, cDNA was synthesized from 2.0 micro g RNA according to the manufacturer's instructions. cDNA was then amplified by PCR. Amplification products were resolved by electrophoresis on a 1.5% agarose gel and stained with EB. The relative quantity of the PCR products were determined and the mRNA levels of OPG, ODF, M-CSF (cofactor of ODF), and RANK (receptor of ODF) were compared with that of the normal bone.</p><p><b>RESULTS</b>GCT contained highly expressed mRNA of ODF, OPG, M-CSF and RANK. There was mRNA expression of OPG, M-CSF and RANK and less expression of ODF in normal bone. The ODF mRNA and RANK mRNA in GCT were more abundant than that in normal bone. In GCT, the ratio of ODF mRNA exceeded OPG expression. But in normal bone, the OPG mRNA exceeded ODF expression.</p><p><b>CONCLUSIONS</b>The results suggest that GCT contains all signals including OPG, ODF, M-CSF and RANK that are essential for inducing osteoclastogenesis and promoting bone resorption.</p>

The nature of calcifying odontogenic cysts of the jaws / 中华病理学杂志

<p><b>OBJECTIVE</b>To clarify the clinicopathological and behavioral spectrum of the so-called calcifying odontogenic cysts (COC).</p><p><b>METHODS</b>Retrospective analysis of 21 cases previously diagnosed as COC was undertaken to evaluate their clinical, radiographic, pathological and behavioral features.</p><p><b>RESULTS</b>The lesions of this series were divided into three groups, including simple cysts, benign and malignant tumors. The cyst group was composed of 16 cases (9 men, 7 women). The age of the patients peaked at the second decade, with a predilection for the premolar region of the jaws. The clinicopathological features of this group were consistent with that of developmental odontogenic cysts. Follow-up of the 13 patients treated by enucleation revealed no recurrence. The benign tumor group consisted of 4 cases with variable clinicopathologic features. Two cases were solid tumors containing ameloblastomatous epithelium, ghost cells and calcification foci. The other two cases had lesions that contained typical areas of COC and other types of odontogenic tumors (1 ameloblastoma and 1 odontogenic fibromyxoma). All the 4 cases occurred in the mandible with a relative large size. Two of which had a history of multiple recurrences. Only one case was identified as malignant tumor based on its infiltrative growth pattern and histological features.</p><p><b>CONCLUSIONS</b>The so-called COC, previously recognized as a pathologic entity, can show extreme diversity in its clinical and histopathological features as well as in its biological behavior. Thus, the subgroups as simple cyst, benign and malignant tumors should be clarified and treated accordingly. Their terminology and classification should be reconsidered.</p>

CHARACTERIZATION,ISOLATION AND CULTURE OF OSTEOCLASTS FROM NEONATAL RAT LONG BONES / 解剖学报

Osteoclasts were isolated mechanically from neonatal rat long bones and cultured on glass or devitalized human cortical bone slices. Both morphological and functional studies showed that the isolated cells were of typical osteoclasts, because; 1. they attached rapidly on the matrix and had pseudopodial activity when cultured on glass;2. they had multinuclei,most of them contained 3-10 nuclei;3. calci-tonin and clacitonin gene related peptide directly inhibited the cellular activity; 4. they showed high acid phosphatase activity; 5. resorption lacunae could be found when the cells cocultured with devitalized bone slices.