Effects of arecoline and calcium ion on the permeability of dysplastic oral epithelia model in vitro / 口腔疾病防治

Objective @# To study the effects of arecolineand Calcium ion (Ca 2+) on the permeability of dysplastic oral epithelia model in vitro.@*Methods@#To establish the dysplastic oral epithelia model in vitro by culturing oral keratinocyte(DOK) and harvesting a DOK cell monolayer. The models were divided into control group, arecoline group and "Ca 2++ arecoline" group. The values of Lucifer Yellow Papp were used to estimate the permeability changes of models after treatedwith arecoline and Ca 2+. @*Results @# In arecoline group, the lucifer yellow Papp values of each subgroup were higher than that of control group (P < 0.05), and the values increased as arecoline concentration elevated and time lasted (P < 0.05). When the "Ca 2++ arecoline" group were pretreated with Ca 2+, the values of subgroup "10 μg/mL" was lower than that of the corresponding arecoline group (P > 0.05). However, the value of subgroup "4 h 10 μg/mL" of "Ca 2++ arecoline" group had no statistical difference with that of control group (P > 0.05), while the other subgroups were increased (P < 0.05); Besides, these values in "Ca 2++ arecoline" group were increased as the arecoline concentration elevated and time lasted too (P < 0.05).@*Conclusion@#Intervention of arecoline contributes to the increase of permeability of DOK cell monolayer model, which maybe an important reason for the cancerization of dysplastic oral epithelia, however Ca 2+might weaken these effects of arecoline in the process.

[Influence of land use change on dissolved organic carbon export in Naoli River watershed. Northeast China].

The present study was conducted to evaluate the influence of land use change on dissolved organic carbon (DOC) export in Naoli River watershed, Northeast China. Seasonal variation of DOC concentrations of the river water and its relationship with land use in the whole watershed and 100 m riparian zone at the annual average scale were analyzed using the method of field sampling, laboratory analysis, GIS and statistics analysis. The results showed that the concentrations of DOC under base flow conditions in spring and summer were significantly higher than that in fall in the study watershed. The seasonal trend of DOC concentrations in wetland-watersheds was similar to that in all the sub-watersheds, while significantly different from that in non-wetland watersheds. On the annual average scale, percentage of wetland in the whole watershed and paddy field in the 100 m riparian zone had positive relationship with the DOC concentration in the river water, while percentage of forest in the whole watershed had negative relationship with it (P < 0.05). It indicated that wetland in the sub-watershed played a significant role in the seasonal variation of DOC in river water of Naoli River watershed. Wetland in the watershed and paddy field in the 100 m riparian zone significantly promoted DOC export, while forest alleviated it. Land use change in the watershed in the past few decades dramatically changed the DOC balance of river water.

Overexpression of BAT3 alleviates prion protein fragment PrP106-126-induced neuronal apoptosis.

BACKGROUNDS AND AIMS: Prion diseases are a group of infectious neurodegenerative diseases characterized by neuronal death and degeneration. Human leukocyte antigen-B-associated transcript 3 (BAT3) is an important apoptosis regulator. We therefore investigated the interactions between BAT3 and prion protein and the potential role of BAT3 in PrP106-126-induced apoptosis. METHODS: BAT3 and prion protein were overexpressed in Hela, Neuro2A, or primary neuronal cells by transfection with BAT3-HA or PRNP-EGFP expression plasmids and their relationship studied by immunofluorescence and Western blotting. The effect of BAT3 on PrP106-126-induced cytotoxicity and apoptosis was detected by the CCK-8 assay and terminal-deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay. The expression of cytochrome c and Bcl-2 was examined by Western blotting. RESULTS: BAT3 interacted with prion protein and enhanced PrP expression. After PrP106-126 peptide treated, BAT3 was transported from the nucleus to cytoplasm, increased cell viability, and protected neurons from PrP106-126-induced apoptosis through stabilizing the level of Bcl-2 protein and inhibiting the release of cytochrome c to cytoplasm. CONCLUSIONS: Our present data showed a novel molecular mechanism of PrP106-126-induced apoptotic process regulation through the overexpression of BAT3, which may be important for the basic regulatory mechanism of neuron survival in prion diseases and associated neurodegenerative diseases in vivo.

Hsp70 binds to PrPC in the process of PrPC release via exosomes from THP-1 monocytes.

PrPC (cellular prion protein) is a GPI (glycophosphatidylinositol)-anchored protein present on the surface of a number of peripheral blood cells. PrPC must be present for the generation and propagation of pathogenic conformer [PrPSc (scrapie prion protein)], which is a conformational conversion form of PrPC and has a central role in transmissible spongiform encephalopathies. It is important to determine the transportation mechanism of normal PrPC between cells. Exosomes are membrane vesicles released into the extracellular space upon fusion of multivesicular endosomes with the plasma membrane. We have identified that THP-1 monocytes can secrete exosomes to culture medium, and the secreted exosomes can bear PrPC. We also found that Hsp70 interacts with PrPC not only in intracellular environment, but in the secreted exosomes. However, the specific markers of exosomes, Tsg101 and flotillin-1, were found with no interaction with PrPC. Our results demonstrated that PrPC can be released from THP-1 monocytes via secreted exosomes, and in this process, Hsp70 binds to PrPC, which suggests that Hsp70 may play a potential functional role in the release of PrPC.

[Research progress of the coupling process of Fe and N in wetland soils].

The coupling process of the earth system is the key research content of earth surface system at present. Wetland is an important ecosystem on the earth surface. Wetland soil is under anaerobic conditions seasonally or perennially because of waterlogging, where the redox of Fe and N can be coupled by microbiology. The coupling process lies in three aspects: the microbial coupling of NO(3-)-reduction and Fe(2+)-oxidation, coupling of Fe(3+)-reduction and NH(4+)-oxidation and the interaction of NO3- and Fe3+ during reduction. Getting the knowledge of the coupling process has important significance to understand the cycles of Fe and N in wetland soil. The article reviews the research status of the three aspects. In general, we have a comparatively deep understand of the coupling process of NO(3-)-reduction and Fe(2+)-oxidation than the latter two aspects. The research of microbial mechanism of the coupling process of Fe(3+)-reduction-NH(4+)-oxidation and the comprehensive evaluation of the environmental significance of coupling process of Fe and N in wetland soil should be strengthened in the future research, and then it can provide evidence for wetland protection and management.

Variable levels of 37-kDa/67-kDa laminin receptor (RPSA) mRNA in ovine tissues: potential contribution to the regulatory processes of PrPSc propagation?

The 37-kDa laminin receptor precursor/67-kDa laminin receptor (LRP/LR, also known as ribosomal protein SA, RPSA) has been reported to be involved in cancer development and prion internalization. Previous studies have shown that the LRP/LR is expressed in a wide variety of tissues. In particular, expression of LRP/LR mRNA may be closely related to the degree of PrP(Sc) propagation. This study presents a detailed investigation of the LRP/LR mRNA expression levels in eleven normal ovine tissues. Using real-time quantitative PCR, the highest LRP/LR expression was found in neocortex (p < 0.05). Slightly lower levels were found in the heart and obex. Intermediate levels were seen in hippocampus, cerebellum, spleen, thalamus, mesenteric lymph node, and the lowest levels were present in liver, kidney, and lung. In general, the LRP/LR mRNA levels were much higher in neuronal tissues than in peripheral tissues. The observation that differences in LRP/LR mRNA expression levels are consistent with the corresponding variation in PrP(Sc) accumulation suggests that the 37-kDa/67-kDa laminin receptor may be involved in the regulation of PrP(Sc) propagation.

[Epidemiological study of betel nut chewing among elementary and middle school students in Loudi city, Hunan province].

OBJECTIVE: To investigate the prevalence of betel nut chewing and oral submucous fibrosis (OSF) among elementary and middle school students in Loudi city, Hunan province. METHODS: According to the standard of the third national oral health epidemiological investigation, the subjects were selected through a two-stage random sampling procedure. A face to face questionnaire survey was conducted among students by random sampling from 6 schools, and oral examination was performed to find the prevalence of OSF. RESULTS: Of the 4087 eligible students, 4019 students participated in the survey(98.3%). Among the 4019 students, there were 498 betel nut chewers, the prevalence of betel nut chewing was 12.4%, which was much higher in male than in female students (437/2073, 21.1% vs 61/1946, 3.1%, P < 0.05). The proportion of students who were chewing areca nuts increased with increasing grades (P < 0.05). The prevalence was highest in senior schools (229/1077, 21.3%)and lowest in elementary schools (126/1983, 6.4%). Most students who were chewing areca nuts in elementary school obtained betel nuts from their parents (61/126, 48.4%), but most middle school betel nut chewers obtained betel nuts from their friends (88/143, 61.5% and 165/229, 72.1%). Five OSF cases (0.12%) were diagnosed among the 4019 students, all of them were male senior school students. CONCLUSIONS: Betel nut chewing was common and OSF cases were found among elementary and middle school students in Loudi city. There were more male than female students who were chewing betel nut.

Changes in FADD levels, distribution, and phosphorylation in TNFalpha-induced apoptosis in hepatocytes is caspase-3, caspase-8 and BID dependent.

FADD/MORT1 (The adaptor protein of Fas Associate Death Domain/Mediator of Receptor Induced Toxicity) is essential for signal transduction of death receptor signaling. We have previously shown that FADD is significantly up-regulated in TNFalpha/ActD induced apoptosis. Over-expression of FADD also induces death of lung cancer cells and primary hepatocytes. We hypothesize that the increase in detectable FADD levels require the proximal steps in apoptotic signaling and speculated that FADD would be redistributed in cells destined to undergo apoptosis. We show that monomeric non-phosphorylated FADD is up-regulated in hepatocytes treated with TNFalpha/ActD and that it accumulates in the cytoplasm. Nuclear phosphorylated FADD decreases with TNFalpha/ActD treatment. Dimeric FADD in the cytoplasm remains constant with TNFalpha/ActD. The change in FADD levels and distribution was dependent on caspase-3, caspase-8 activity and the presence of BID. Thus, changes in FADD levels and distribution are downstream of caspase activation and mitochondria changes that are initiated by the formation of the DISC complex. Changes in FADD levels and distribution may represent a novel feed-forward mechanism to propagate apoptosis signaling in hepatocytes.

[Effects of arecoline and nicotine on the expression of hTERT in oral keratinocytes].

OBJECTIVE: To investigate the effects of arecoline and nicotine on the expression of human telomerase reverse transcriptase (hTERT) mRNA and protein in cultured normal human oral keratinocytes (KC). METHODS: The experiments were divided into arecoline group, arecoline/nicotine group and control group. The hTERT mRNA and protein expression of KC was examined by reverse transcription polymerase chain reaction (RT-PCR) and Western blot. RESULTS: Arecoline could induce the hTERT mRNA and protein expression of KC in a dose dependent manner, the hTERT mRNA and protein expression of KC was higher in 0.030, 0.060, 0.090 g/L arecoline group than control group (P < 0.001). Nicotine (0.025 g/L) increased hTERT mRNA and protein expression of KC induced by arecoline. CONCLUSIONS: Arecoline could increase the expression of hTERT mRNA and protein in oral keratinocytes. Nicotine had a synergistic effect on arecoline. hTERT over-expression induced by arecoline and nicotine may play an important role in the malignant transformation of oral submucous fibrosis.

[Clinical study on the relationship between tooth abrasion and the habits of chewing betel nut].

OBJECTIVE: To investigate the relationship between tooth abrasion and long-term chewing betel nut. METHODS: The time, frequency, clinical features of occlusal abrasion, and results of pantomography were studied in 64 patients with the habits of chewing betel nut. RESULTS: The occlusal surfaces of all patients had abrasion from mild to severe. The longer the chewing time, the more severe the occlusal abrasion (P < 0.01). The occlusal abrasion became more severe with the increase in chewing frequency (P < 0.01). The severe abrasion was accompanied with periapical periodontitis and the resorption of alveolar bone. CONCLUSION: Long-term chewing betel nut can result in the abrasion of occlusal surface.