An aptamerelectrochemical sensor based on functional carbon nanofibers for tetracycline determination

Fe-Co@CNF was synthesized by electrospinning technology, and AuNPs was loaded onto Fe-Co@CNF by in-situ reduction to obtain Fe-Co@CNF@AuNPs composite material, which was used as the working electrode based on Au-S bond cooperation. The tetracycline electrochemical sensing interface Fe-Co@CNF@AuNPs@Apt was constructed by connecting mercaptoylated tetracycline (TC) aptamers on Fe-Co@CNF@AuNPs surface. The morphology and composition of Fe-Co@CNF@AuNPs composites were characterized by SEM, TEM, EDS, XRD and XPS, and the electrochemical properties of tetracycline were evaluated by CV and DPV. The results showed that the addition of Fe and Co did not destroy the structure of the original carbon nanofibers, and their synergistic effect enhanced the electrocatalytic performance, effective electrode area and electron transfer ability of carbon nanofibers. AuNPs are evenly distributed over the fibers, which effectively improves the electrical conductivity of the material. Under the optimal conditions, the theoretical detection limit of tetracycline was 0.213 nM, and the linear detection range was 5.12-10 mM, which could successfully detect tetracycline in milk.

[Re-understanding the role of enamel matrix proteins in periodontal regeneration]

Enamel matrix proteins (EMP) are deposited on the surface of developing roots before dentin formation and may play a role in osteogenesis. Amelogenins (Am) are the main and active component in EMPs. Studies had showed great clinical values of EMPs in periodontal regenerative treatment and other fields. By affecting the expression of growth factors and inflammatory factors, EMPs could act on various periodontal regeneration-related cells to promote angiogenesis, anti-inflammation, bacteriostasis and tissue healing, achieving the clinical effect of periodontal tissue regeneration (newly generated cements and alveolar bones as well as functionally penetrated periodontal ligament). EMPs alone or combined with bone graft material and barrier can be used for regenerative surgical treatment in intrabony defects and degree Ⅱ furcation-involved at maxillary buccal or mandibular teeth. EMPs can also be adjunctively used to treat recession type 1 or 2 gingival recessions, forming periodontal regeneration on the exposed root surface. Through a comprehensive understanding of the principle and current clinical application of EMPs on periodontal regeneration, we can look forward to their future development. The development of recombinant human amelogenin to replace animal-derived EMPs through bioengineering technologies, the study of the clinical application of EMPs combined with other collagen biomaterials, and the specific application of EMPs in severe soft and hard periodontal tissue defects and peri-implant lesions are all important development directions of future EMPs-related researches.

[Analyzing the relevant factors affecting the clinical outcome of periodontal regeneration surgery]

Periodontitis can lead to periodontal tissue defect, tooth mobility and loss, which seriously affects the quality of life. Periodontal regeneration surgery is an important treatment method for repairing periodontal defects, and it is also the hotspot of current periodontal clinical and basic research. A comprehensive understanding of the factors affecting the efficacy of periodontal regenerative surgery can improve clinicians' periodontal treatment concepts, increases the predictability of treatment results, and enhances the level of clinical diagnosis and periodontal treatment. In order to instruct the clinicians, this article will explain the basic principles of periodontal regeneration and the key points of periodontal wound healing, and analyze the elements of periodontal regeneration surgery, which including the patient-related factors, local factors, surgical factors and regenerative material selection.

[Preliminary study on the relationship between different blood glucose levels and periodontitis in patients with diabetes mellitus type 2]

Objective: To determine the correlation between the diabetes mellitus control and periodontitis. Methods: This study was a cross-sectional survey using stratified system sampling model design. The target population was the patients with diabetes investigated from May to July 2018 in Huangpu District of Shanghai. In the present study, severe periodontitis was defined as at least at two sites in different quadrants with probing depth (PD)≥6 mm and clinical attachment loss (CAL)≥ 5 mm. Edentulous induced by periodontitis were also classified as severe periodontitis and the others were classified as non-severe periodontitis subjects. Diabetes control levels were divided into the following three groups: poorly controlled group [glycated hemoglobin (HbA1c)>7.5% and fasting blood glucose (FPG)>7.0 mmol/L], well controlled group (6.5%≤HbA1c≤7.5％ or 6.1 mmol/L≤FPG≤7.0 mmol/L) and ideally controlled group (HbA1c<6.5% and FPG<6.1 mmol/L). SPSS 25.0 was used for statistical analysis. Chi square test was used for demographic data and frequency distribution, α=0.05, two-sided test. Ordinal regression model was used for PD and diabetes control status to balance confounding factors (including age, gender, education and smoking status). After matching the propensity scores between severe periodontitis group and non-severe periodontitis group, logistic regression analysis was used to analyze the level of diabetes control and periodontitis. Results: A total of 5 220 adults over the age of 18 with a medical history of diabetes participated in the survey, of which 3 064 subjects with diabetes mellitus type 2 (T2DM) who were given both oral and laboratory examinations and were included in this study. Statistics showed that the prevalence of moderate and severe periodontitis was 10.57% (324/3 064). In the severe periodontitis group, 79.01% (256/324) of the subjects were over 65 years old, 55.56% (180/324) were male, 58.33% (189/324) had lower education level than high school level, and 21.91% (71/324) were smokers, which were significantly higher than those in the non-severe periodontitis group (P<0.01). In different T2DM status groups, the percentage of severe periodontitis increased with the aggravation of T2DM status. In severe periodontitis group, the proportion of patients with poor glycemic control was higher. T2DM patients with poor glycemic control accounted for 68.52% (222/324) in severe periodontitis group, which was significantly higher than the proportion of non-severe periodontitis group of 60.99% (1 671/2 740) (P<0.05). The regression coefficient of PD was 0.191, and PD had a significant negative effect on the level of blood glucose (P<0.01). There was a significant positive correlation between diabetes glycemic control and severe periodontitis (OR=2.800, P<0.05). Conclusions: In Huangpu District of Shanghai, among T2DM patients, the age of severe periodontitis group was higher than that of non-severe periodontitis group, most of them were male, with lower education level and higher proportion of smoking. The severity of diabetes was related to periodontitis and the proportion of severe periodontitis was higher in patients with poor glycemic control.

Enamel matrix proteins regulate hypoxia-induced cellular biobehavior and osteogenic differentiation in human periodontal ligament cells

Hypoxia is a crucial microenvironment for inflamed periodontal tissue and periodontal wound healing. Enamel matrix proteins (EMPs) potentially can promote the formation of new periodontium. The effects of EMPs on periodontal ligament cells under hypoxia, however, remain unclear. We investigated the effects of EMPs on cellular biobehavior and osteogenic differentiation of human periodontal ligament cells (hPDLCs) under hypoxia. Under cobalt chloride (CoCl₂)-induced hypoxia, cellular biobehavior of hPDLCs, including proliferation, attachment, spreading, and migration with or without EMPs, was evaluated by 3-(4, 5-dimethylthiazol- 2-yl)-2, 5-diphenyl tetrazolium bromide (MTT), cell counting, spreading area measurement and wound scratch assay. The osteogenic activity of hPDLCs was assessed using alkaline phosphatase (ALP) and alizarin red S staining (ARS). The expressions of osteogenic genes including runt related transcription factor 2 (Runx2), ALP, osteocalcin (OCN) and collagen type I (Col-I) were detected using real time quantitative PCR, western blot and immunocytochemistry assays. The biobehavior and osteogenic differentiation of hPDLCs were inhibited significantly under hypoxia. EMPs have no effect on cell proliferation under mimicked hypoxia. EMPs partly reversed the inhibitory effects of hypoxia, however, for other cellular biobehavior including attachment, spreading and migration, and markedly up-regulated osteogenic differentiation activities including ALP, mineralization ability and the expressions of osteogenic genes such as Runx2, ALP, osteocalcin, and collagen type I in hPDLCs under hypoxia. EMPs attenuate the hypoxic injury to cellular biobehavior and osteogenic differentiation in hPDLCs under hypoxia.

A CMOS millimeter-wave transceiver embedded in a semi-confocal Fabry-Perot cavity for molecular spectroscopy

The extension of radio frequency complementary metal oxide semiconductor (CMOS) circuitry into millimeter wavelengths promises the extension of spectroscopic techniques in compact, power efficient systems. We are now beginning to use CMOS millimeter devices for low-mass, low-power instrumentation capable of remote or in situ detection of gas composition during space missions. We have chosen to develop a Flygare-Balle type spectrometer, with a semi-confocal Fabry-Perot cavity to amplify the pump power of a mm-wavelength CMOS transmitter that is directly coupled to the planar mirror of the cavity. We have built a pulsed transceiver system at 92-105 GHz inside a 3 cm base length cavity and demonstrated quality factor up to 4680, allowing for modes with 20 MHz bandwidth, with a sufficient cavity amplification factor for mW class transmitters. This work describes the initial gas measurements and outlines the challenges and next steps.

Effects of extracellular DNA and DNA-binding protein on the development of a Streptococcus intermedius biofilm

AIMS

The aim of this study was to clarify the effects of homologous and heterologous extracellular DNAs (eDNAs) and histone-like DNA-binding protein (HLP) on Streptococcus intermedius biofilm development and rigidity.

METHODS AND RESULTS

Formed biofilm mass was measured with 0·1% crystal violet staining method and observed with a scanning electron microscope. The localizations of eDNA and extracellular HLP (eHLP) in formed biofilm were detected by staining with 7-hydoxyl-9H-(1,3-dichloro-9,9-dimethylacridin-2-one) and anti-HLP antibody without fixation, respectively. DNase I treatment (200 U ml(-1)) markedly decreased biofilm formation and cell density in biofilms. Colocalization of eHLP and eDNA in biofilm was confirmed. The addition of eDNA (up to 1 μg ml(-1)) purified from Strep. intermedius, other Gram-positive bacteria, Gram-negative bacteria, or human KB cells into the Strep. intermedius culture increased the biofilm mass of all tested strains of Strep. intermedius, wild-type, HLP-downregulated strain and control strains. In contrast, the addition of eDNA (>1 μg ml(-1)) decreased the biofilm mass of all Strep. intermedius strains.

CONCLUSIONS

These findings demonstrated that eDNA and eHLP play crucial roles in biofilm development and its rigidity.

SIGNIFICANCE AND IMPACT OF THE STUDY

eDNA- and HLP-targeting strategies may be applicable to novel treatments for bacterial biofilm-related infectious diseases.

Analogous effects of recombinant human full-length amelogenin expressed by Pichia pastoris yeast and enamel matrix derivative in vitro

OBJECTIVES

Amelogenins are proposed to be responsible for enamel matrix derivative (EMD)-induced periodontal regeneration; however, heterogeneity of amelogenins makes it challenging to purify the full-length proteins. This study has been carried out to express and purify a recombinant full-length human amelogenin protein (rHhAm175) in the eukaryotic yeast Pichia pastoris, and further compare biological responses of human periodontal ligament fibroblasts (PDLFs) to rHhAm175 and porcine EMD (pEMD).

MATERIALS AND METHODS

Human cDNA encoding a 175-amino acid amelogenin was subcloned into the pPIC3.5K vector. The rHhAm175 expressed in P. pastoris GS115 (Mut+) was purified and characterized. We examined cell attachment, migration and proliferation responses of human PDLFs to rHhAm175 and pEMD respectively, and characterized associated changes of proliferation-related intracellular signalling molecules, including extracellular signal response kinase (ERK) and Akt kinases/protein kinase B (Akt/PKB) kinases.

RESULTS

The purified rHhAm175 was confirmed to be molecular mass 22 021.13 Da, phosphorylated human amelogenin, and alone significantly promoted proliferation and migration of human PDLFs to an extent comparable to that of pEMD. Cell attachment was increased over the first 60 min incubation with rHhAm175 or pEMD. Both rHhAm175 and pEMD induced PDLF mitogenesis via extracellular signal response kinase (ERK1/2), but not by Akt kinases/protein kinase B (Akt/PKB).

CONCLUSIONS

rHhAm175 modulated cell activities of human PDLFs, to a comparable extent as porcine EMD. These data suggest that rHhAm175 might be used to induce periodontal tissue regeneration.

Hypoxia induces apoptosis and autophagic cell death in human periodontal ligament cells through HIF-1α pathway

OBJECTIVES

Oxygen deficiency caused by occlusal trauma and smoking can be present in patients with periodontitis. However, biochemical events important in periodontal tissues during hypoxia remain unclear. The aim of this study was to investigate effects of hypoxia on apoptosis and autophagy of human periodontal ligament cells (PDLCs) in vitro.

MATERIALS AND METHODS

Human PDLCs were obtained and cultured in vitro. Cell viability, apoptosis, autophagy and gene and protein expression were measured in presence and absence of cobalt chloride (CoCl(2)).

RESULTS

CoCl(2) induced cytotoxicity of human PDLCs in a concentration-dependent manner dependent on macromolecular synthesis, and resulted in apoptosis and mitochondrial dysfunction. CoCl(2) also induced redistribution of autophagy marker LC3, increased ratio of LC3-IIto LC3-Iand function of lysosomes. Furthermore, CoCl(2) promoted expression of HIF-1α following upregulation of expressions of Bnip3. Significant increases in expression of IL-1β and MMP-8 were also observed. All these results were reversed by pre-treatment with antioxidant N-acetylcysteine.

CONCLUSIONS

Our data showed that CoCl(2) could induce cytotoxicity through mitochondria- apoptotic and autophagic pathways involved in HIF-1α. CoCl(2 -treated PDLCs may serve as an in vitro model for studies of molecular mechanisms in periodontitis.

Effects of enamel matrix proteins on proliferation, differentiation and attachment of human alveolar osteoblasts

OBJECTIVES

Enamel matrix proteins (EMPs) have been demonstrated to promote periodontal regeneration. However, effects of EMPs on human alveolar osteoblasts (hAOBs), up to now, have still been unclear. The purpose of this study was to investigate influence of EMPs on proliferation, differentiation and attachment of hAOBs in vitro.

MATERIALS AND METHODS

EMPs were extracted using the acetic acid method, hAOBs were obtained and cultured in vitro. Cell proliferation, alkaline phosphatase (ALP) activity, mRNA expression of osteogenic markers and cell attachment were measured in the absence and in the presence of EMPs (50, 100 and 200 μg/ml).

RESULTS

EMPs increased proliferation of hAOBs; however, they inhibited ALP activity and mRNA expression of osteogenic markers (collagen I, ALP, runt-related protein 2, osteocalcin, bone sialoprotein and osteopontin). Meanwhile, EMPs hindered hAOBs' attachment. These effects occurred in EMPs concentration-dependent manner.

CONCLUSIONS

These results indicate that EMPs may inhibit osteoblastic differentiation and attachment to prevent ankylosis and allow other cell types to regenerate periodontal tissues.

Age-related changes in biological characteristics of human alveolar osteoblasts

OBJECTIVES

Age-related changes are common in many tissues and organs. However, cell-related causes in human alveolar bone remain unclear. This study has been carried out to explore the possibility that advancing age might change the biological characteristics of alveolar osteoblasts (AOBs) in women.

MATERIALS AND METHODS

Alveolar osteoblasts from women donors (five women aged 33-38 years and five women aged 62-68 years) were cultured in vitro. The cells were serially passaged and maximal lifespan evaluated. Cell viability, ultramicrostructure and osteogenic differentiation ability were determined respectively, using MTT assay, transmission electron microscopy, alkaline phosphatase (ALP) activity assay and von Kossa staining assay. These parameters of the two groups of AOBs were evaluated.

RESULTS

When compared with cells from young adult donors, AOBs from elderly women exhibited lower maximal lifespan (P < 0.05). Mean rate of population doubling was lower in elderly donor cells compared to those from young adult cells (P < 0.05). Organelles from AOBs of elderly donors were much fewer than those from young donors. MTT value of elderly donor cells was significantly lower than those of young adult donors from day 2 (P < 0.05). Relative ratio of ALP activity in elderly donor cells was significantly lower than those of the young womens' cells at 8, 12, 16 and 20 days (P < 0.05). Calcium nodules of young adult donors' specimens were significantly more numerous and larger than those from elderly donors.

CONCLUSIONS

Comparison of biological characteristics of AOBs from young adult women with those from elderly women in vitro revealed differences in proliferative capacity and bone formation functions, which decreased with aging. These data indicate that aging may play an important role in pathogenesis of human AOBs loss.

Cellular responses and expression profiling of human bone marrow stromal cells stimulated with enamel matrix proteins in vitro

OBJECTIVES

The aim of this study was to investigate biological effects and gene expression profiles of enamel matrix proteins (EMPs), on human bone marrow stromal cells (HBMSCs), for preliminary understanding of mechanisms involved in promoting periodontal regeneration by EMPs.

MATERIALS AND METHODS

EMPs were extracted using the acetic acid method, and HBMSCs from human bone marrow aspirates were cultured. Attachment levels, level of cells morphologically attenuated, cell proliferation, alkaline phosphatase (ALP) activity and staining of HBMSCs were measured in the absence and in the presence of EMPs. Microarray analysis was performed to detect gene profiles of HBMSCs by treatment with 200 microg/ml EMPs, for 5 days. Four differential genes were selected for validation of the microarray data using real-time PCR.

RESULTS

EMPs promoted proliferation and ALP activity of HBMSCs in a time- and dose-dependent manner, and at a concentration of 200 microg/ml significantly enhanced proliferation and ALP expression. However, there were no significant changes between EMP-treated groups and the control group in cell attachment and cell process attenuation levels. Twenty-seven genes were differentially expressed by HBMSCs in the presence of EMPs. Expressions of 18 genes were upregulated and expressions of nine genes were found to be downregulated. There was good consistency between data obtained from the validation group and microarray results.

CONCLUSIONS

EMPs promoted cell proliferation and differentiation and gene expression profiles of HBMSCs were affected. This may help elucidation of mechanisms involved in promoting regeneration of periodontal tissues by EMPs.

Initial comparison of proteomic profiles of whole unstimulated saliva obtained from generalized aggressive periodontitis patients and healthy control subjects

BACKGROUND AND OBJECTIVE

Salivary proteomics technology can be used to evaluate the disease progression of periodontitis and the systemic screening of proteomes of saliva from subjects with aggressive periodontitis has not been available. The objective of this preliminary study was to compare the proteomic profile of whole unstimulated saliva of subjects with generalized aggressive periodontitis (GAgP) with that of healthy volunteers to identify proteins, the levels of which were significantly altered between the two groups.

MATERIAL AND METHODS

Whole unstimulated saliva was obtained from five subjects with GAgP and five healthy subjects, and proteins were separated using two-dimensional gel electrophoresis. Proteins, the levels of which were significantly different between the two groups, were identified by computer image analyses and subsequent electrospray ionization tandem mass spectrometry.

RESULTS

Eleven proteins that exhibited a different level in the GAgP group vs. the control group were identified. Compared with whole saliva of healthy control subjects, the levels of serum albumin, immunoglobulin (Ig) gamma2 chain C region, Ig alpha2 chain C region, vitamin D-binding protein, salivary alpha-amylase and zinc-alpha2 glycoprotein were increased in whole unstimulated saliva of GAgP subjects, while those of lactotransferrin, elongation factor 2, 14-3-3 sigma, short palate, lung and nasal epithelium carcinoma-associated protein 2 precursor and carbonic anhydrase 6 were decreased.

CONCLUSION

Comparison of the proteomic profile of whole unstimulated saliva of GAgP subjects with that of healthy control subjects revealed at least 11 differential proteins. The approach applied herein might be helpful to aid understanding of the etiology of GAgP.

A study of enamel matrix proteins on differentiation of porcine bone marrow stromal cells into cementoblasts

OBJECTIVE

To further explore the role of enamel matrix proteins (EMPs) in periodontal regeneration, we have used porcine bone marrow-derived stromal cells (BMSCs) to observe whether the EMPs could have an effect on their differentiation into cementoblasts.

MATERIALS AND METHODS

In this study, EMPs were extracted from porcine tooth germs by the use of acetic acid. BMSCs obtained from porcine iliac marrow aspiration were inoculated onto the surface of autologous root slices treated with or without EMPs. Following 7-day co-culture, all the BMSC-seeded root slices, with their respective non-cell-inoculated control specimens, were pocketed with expanded polytetrafluoroethylene membrane and were transplanted subcutaneously into 11 nude mice. The animals were sacrificed after 3 and 8 weeks, and the new specimens were processed for haematoxylin and eosin staining.

RESULTS

Histological analysis demonstrated new cellular cementum-like tissue formed along EMP-treated root slices.

CONCLUSION

Our work has indicated for the first time, differentiation of BMSCs into cementoblasts using an EMP-based protocol.

Hydroxyapatite accelerates differentiation and suppresses growth of MC3T3‐E1 osteoblasts

Hydroxyapatite describes both the natural mineral phase of bone as well as the widely used calcium-phosphate implant substitute. Given that hydroxyapatite is a major component of the in vivo surface with which osteoblasts interact, it is surprising that most studies examining the regulation of osteoblast growth and differentiation utilize plastic surfaces. Here we demonstrate that the phenotype of mouse MC3T3-E1 osteoblasts is significantly altered on hydroxyapatite compared with plastic surfaces. Specifically, alkaline phosphatase activity and messenger RNA levels, markers of early stages of osteoblast differentiation, are increased in osteoblasts cultured on hydroxyapatite. The precocious appearance of alkaline phosphatase activity on the hydroxyapatite surface suggests that osteoblast differentiation is activated earlier compared with plastic surfaces. Osteocalcin expression, a marker of late-stage differentiation, is also increased on hydroxyapatite and further demonstrates enhanced differentiation. Cell counts indicate that fewer osteoblasts are present on hydroxyapatite versus plastic surfaces 24 h after plating. Measurement of osteoblast attachment, apoptosis, and necrosis indicated no differences between surfaces. In contrast, the number of bromodeoxyuridine-incorporating cells was significantly decreased on hydroxyapatite compared with plastic surfaces. Taken together, our findings indicate that hydroxyapatite enhances osteoblast differentiation while also suppressing growth.

[A study of fluoride and dexamethasone affecting the expression of growth factors in osteoblast]

OBJECTIVES

Investigate the expression of growth factors or receptors in osteoblast, to understand the possible mechanism of low dose fluoride and dexamethasone on the development and differentiation of osteoblast.

METHODS

Investigate the expression of platelet derived growth factors (PDGF-A) and insulin-like growth factors (IGF-I-Ralpha) in osteoblast cultured in vitro by immunohistochemistry, furthermore, to deal with the results by image analysis.

RESULTS

There were no significant effects of PDGF-A both of low doses fluoride and dexamethasone treated on the MC3T3-E1 osteoblast during the various stages of the development. Otherwise, the expression of IGF-I-Ralpha might increase treated with them at the early stage of the cell culture, and dexamethasone did more significantly.

CONCLUSION

Low doses of fluoride or dexamethasone may promote the expression of IGF-I-Ralpha in osteoblast precursors, which maybe contribute to the effects of fluoride and dexamethasone on the proliferation and differentiation of osteoblast.

[Surface characteristic of domestic poly-DL-lactic acid membrane for periodontal guided tissue regeneration]

OBJECTIVE

To evaluate the surface characteristic of domestic poly-DL-lactic acid membrane for periodontal guided tissue regeneration.

METHODS

Three guided tissue regeneration membranes (PDLLA, ePTFE, COL)were implanted in rats subcutaneously, then they were removed 2,4,8 weeks after surgery for examination under scanning electron microscope. The membranes in vitro served as control.

RESULTS

The surface of PDLLA membrane was characterized by unorganized smooth film structure. After 2 weeks implanted subcutaneously, its surface became rough with numerous oval micropores in it. These oval micropores were 5 microm in size.The micropores increased gradually in size and number 4, 8 weeks after implantation,there were many shindle shaped cells inlayed.

CONCLUSION

Domestic Poly-DL-lactic acid membrane exhibits excellent biocompatibility,which meets the criterion for GTR.

[Histological evaluation of the biocompatibility of PDLLA membranes]

OBJECTIVE

To evaluate the histological response and biocompatibility of implanted domestic bio-degradable PDLLA membranes in vivo.

METHODS

The domestic biodegradable PDLLA membranes and non-degradable ePTFE membranes were in pairs placed subcutaneously in surgical incision made in the dorsum of rats. The tissue responses to these materials were observed histologically at 1, 2, 4, 8 and 12 weeks after placement.

RESULTS

The tissue responses of the two kinds of materials were similar to the non-specific reaction mainly infiltrated with lymphocytes, plasmocytes, macrophages, and foreign body giant cells. The polymorphonuclears and foreign body giant cells infiltrated round the ePTFE membranes existed for a relatively long period, in contrast to that of PDLLA membranes.

CONCLUSION

Domestic PDLLA membranes with good biocompatibility will be adapted to making GTR into a single step procedure.

[A study of fluoride and dexamethasone affecting the proliferation in osteoblast]

OBJECTIVE

Investigate the effects of low dose of fluoride and dexamethasone on the proliferation of MC3T3-E1 osteoblast cell line in vitro, which was for determining the possible effects of fluoride and dexamthasone affecting the development and differentiation of osteoblast.

METHODS

Observe the growing shape of MC3T3-E1 osteoblast cultured in vitro, and investigate the effects of low dose of fluoride and dexamethasone on the proliferation of osteoblast by cell count.

RESULTS

MC3T3-E1 osteoblast grew stably. The cells in D group increased obviously in the early stage of the cell culture, however the cells in F group had no tendency of increasing during the whole culture.

CONCLUSION

In vitro low doses of dexamethasone may promote the proloferation of osteoblast precursors,however,low dose of fluoride has no effect on promoting proliferation of MC3T3-E1 osteoblast.

[Influences of porcine enamel matrix proteins on MC3T3-E1 osteoblast proliferation and differentiation]

OBJECTIVE

Some research suggested that enamel matrix proteins(EMPs) not only induced formation of cementum, but also could promote regeneration of periodontal tissue and alveolar bone. In order to recognize the mechanisms of periodontal regeneration induced by EMPs and provide a basic data for further study, influences of EMPs on osteoblast proliferation and differentiation are explored in this study.

METHODS

Porcine enamel matrix proteins were extracted by using acetic acid. MC3T3-E1 osteoblasts were selected and cell culture was used in vitro. EMPs with different concentrations of 50 micrograms/ml, 100 micrograms/ml and 150 micrograms/ml were added separately in alpha-MEM culture medium and compared with negative group and positive group (TGF-beta 1). The count of cell was recorded after 0, 1, 2, 3, 4, 5, 6 days, then the data were analysed statistically by using SAS.

RESULTS

The cell count of all EMPs groups were higher than that in the negative control group (P < 0.01), 100 micrograms/ml as well as 150 micrograms/ml EMPs groups were higher than the positive group(TGF-beta 1) on the second day (P < 0.01). The cell count of 100 micrograms/ml EMPs group was not only higher than C and T groups, but also higher than that of other EMPs dose groups on the fifth day.

CONCLUSION

The proliferation and differentiation of osteoblasts can be promoted distinctly by enamel matrix proteins.

[A clinical study on prosthodontic treatment of periodontal problems with conical telescopic removable denture]

OBJECTIVE:Clinical study was made on curative effect of medium to severe periodontal diseases as well as those complicated with partial edentulism by conical telescopic removable denture.METHODS:14 cases of medium to severe periodontal diseases and these complicated with partial edentulism were treated with prosthodontic methods after comprehensive periodontal therapy.Examinations of both before and following prosthetic restoration of 3,12,14 months were made.Bacterial plague index,gingival index,tooth movability and masticatory efficiency were recorded,analysed and compared. RESULTS:Periodontal plague attachment was under effective control through this way,which also eliminated periodontal trauma thus preventing the relapse of periodontal diseases.Further more it can diminish tooth movability and improve masticatory efficiency continuously as time goes on.CONCLUSION:Conical telescopic removable denturs is an effective prosthetic method in treating medium to severe periodontal diseases.

Luminal fructose modulates fructose transport and GLUT-5 expression in small intestine of weaning rats

In neonatal rats, precocious introduction of dietary fructose significantly enhances brush-border fructose transport rates and GLUT-5 mRNA levels during early weaning. In this study, these rates and levels were more than two times higher in the anastomosed intestine compared with those in the bypassed loop of weaning pups that underwent Thiry-Vella surgery and consumed high-fructose (HF) diets. In Thiry-Vella pups fed fructose-free (NF) diets, uptake rates and mRNA levels in the anastomosed intestine were very low and similar to those in the bypassed loop. In sham-operated littermates, transport rates and mRNA levels were similar between intestinal regions that corresponded to anastomosed and bypassed loops in Thiry-Vella pups and were two to three times greater in pups fed HF than in those fed NF diet. In contrast, rates of brush-border glucose transport and levels of SGLT-1 and of GLUT-2 mRNA were independent of diet and were similar between bypassed and anastomosed regions. Changes in GLUT-5 expression did not follow a distinct diurnal rhythm. When pups were fed HF diet after 12 h of starvation to empty the intestinal lumen, fructose transport rates increased with feeding duration and reached a plateau 12-24 h after feeding; in contrast, GLUT-5 mRNA levels were highest within 4 h after arrival of chyme in the jejunum and then decreased gradually and returned to baseline levels 24 h later. In littermates fed NF diet, mRNA levels and uptake rates were each independent of feeding duration. Luminal, and not endocrine, signals regulate GLUT-5 expression in weaning pups.

Dietary fructose enhances intestinal fructose transport and GLUT5 expression in weaning rats

Rates of fructose uptake by the small intestine of neonatal rats are typically very low from parturition through weaning but undergo a dramatic increase immediately after weaning is completed. In this study, we used intestinal fructose transport as a model to determine whether nutrient transport, normally enhanced only after completion of weaning, can be enhanced earlier during development. We found that ontogenetic changes in levels of GLUT5 mRNA correlate well with already known ontogenetic changes in rates of intestinal fructose transport: low levels and rates during suckling and weaning, and high levels and rates after weaning. In contrast, levels of GLUT2 and SGLT1 mRNA were relatively more elevated throughout the suckling and weaning periods. We then found that increased expression of GLUT5 mRNA caused by dietary fructose or sucrose paralleled diet-dependent increases in brush-border fructose uptake. Rates of brush-border glucose uptake and levels of SGLT1 and GLUT2 mRNA were not enhanced by dietary fructose, glucose, or sucrose. Finally, we found that rates of fructose uptake, levels of GLUT5 mRNA, and specific sucrase activity each increased with increasing concentrations of dietary fructose given precociously to midweaning rats. In contrast, brush-border glucose uptake was independent of dietary fructose concentration. Thus precocious introduction of dietary fructose causes enhanced expression of fructose transporters earlier during development. This effect is specific: only luminal fructose is effective, and only brush-border fructose transport can be modulated. These results unveil the potential for regulating nutrient transport early in development.

[Chemical constituents of Cyclocarya paliurus (Batal.) Iljinsk]

Four compounds were isolated from the leaves of Cyclocarya paliurus. They were identified as daucosstero, beta-L-arabopyranose, steraric acid and palmitic acid on the basis of spectral data and chemical properties. All of them were isolated from this plant for the first time.