RÉSUMÉ
Skeletal fluorosis is a chronically metabolic bone disease with extensive hyperostosis osteosclerosis caused by long time exposure to fluoride. Skeletal fluorosis brings about a series of abnormal changes of the extremity, such as joint pain, joint stiffness, bone deformity, etc. Differentiation and maturation of osteoblasts were regulated by osteoclasts via Sema4D/Plexin-B1 signaling pathway. Furthermore, the differentiation and maturation of osteoclasts are conducted by osteoblasts via RANKL/RANK/OPG pathway. Both of these processes form a feedback circuit which is a key link in skeletal fluorosis. In this study, an osteoblast-osteoclast co-culture model in vitro was developed to illustrate the mechanism of skeletal fluorosis. With the increase of fluoride concentration, the expression level of Sema4D was decreased and TGF-β1 was increased continuously. OPG/RANKL mRNA level, however, increased gradually. On the basis of that, the inhibition of Sema4D/Plexin-B1/RhoA/ROCK signaling pathway caused by fluoride promoted the level of TGF-β1 and activated the proliferation of osteoblasts. In addition, osteroprotegerin (OPG) secreted by osteoblasts was up-regulated by fluoride. The competitive combination of OPG and RANKL was strengthened and the combination of RANKL and RANK was hindered. And then the differentiation and maturation of osteoclasts were inhibited, and bone absorption was weakened, leading to skeletal fluorosis.
Sujet(s)
Animaux , Rats , Antigènes CD , Génétique , Métabolisme , Prolifération cellulaire , Rétrocontrôle physiologique , Foetus , Fluorures , Pharmacologie , Protéines d'activation de la GTPase , Génétique , Métabolisme , Régulation de l'expression des gènes au cours du développement , Ostéoblastes , Métabolisme , Anatomopathologie , Ostéoclastes , Métabolisme , Anatomopathologie , Ostéogenèse , Génétique , Ostéoprotégérine , Génétique , Métabolisme , Ligand de RANK , Génétique , Métabolisme , ARN messager , Génétique , Métabolisme , Récepteur activateur du facteur nucléaire Kappa B , Génétique , Métabolisme , Récepteurs de surface cellulaire , Génétique , Métabolisme , Sémaphorines , Génétique , Métabolisme , Transduction du signal , Facteur de croissance transformant bêta-1 , Génétique , Métabolisme , rho-Associated Kinases , Génétique , Métabolisme , Protéine G RhoA , Génétique , MétabolismeRÉSUMÉ
<p><b>OBJECTIVE</b>To study the method of concentration determination of mineral-oil fog in the air of workplace.</p><p><b>METHODS</b>Four filter films such as synthetic fabric filter film, beta glass fiber filter film, chronic filter paper and microporous film were used in this study. Two kinds of dust samplers were used to collect the sample, one sampling at fast flow rate in a short time and the other sampling at slow flow rate with long duration. Subsequently, the filter membrane was weighed with electronic analytical balance. According to sampling efficiency and incremental size, the adsorbent ability of four different filter membranes was compared.</p><p><b>RESULTS</b>When the flow rate was between 10 approximately 20 L/min and the sampling time was between 10 approximately 15 min, the average sampling efficiency of synthetic fabric filter film was 95.61% and the increased weight ranged from 0.87 to 2.60 mg. When the flow rate was between 10 approximately 20 L/min and sampling time was between 10 approximately 15 min, the average sampling efficiency of beta glass fiber filter film was 97.57% and the increased weight was 0.75 approximately 2.47 mg. When the flow rate was between 5 approximately 10 L/min and the sampling time between 10 approximately 20 min, the average sampling efficiency of chronic filter paper and microporous film was 48.94% and 63.15%, respectively and the increased weight was 0.75 approximately 2.15 mg and 0.23 approximately 0.85 mg, respectively. When the flow rate was 3.5 L/min and the sampling time was between 100 approximately 166 min, the average sampling efficiency of filter film were 94.44% and 93.45%, respectively and the average increased weight was 1.28 mg for beta glass fiber filter film and 0.78 mg for beta glass fiber filter film and synthetic fabric synthetic fabric filter film. The average sampling efficiency of chronic filter paper and microporous film were 37.65% and 88.21%, respectively. The average increased weight was 4.30 mg and 1.23 mg, respectively.</p><p><b>CONCLUSION</b>Sampling with synthetic fabric filter film and beta glass fiber filter film is credible, accurate, simple and feasible for determination of the concentration of mineral-oil fog in workplaces.</p>
Sujet(s)
Air , Polluants atmosphériques d'origine professionnelle , Filtration , Huile minérale , Smog , Lieu de travailRÉSUMÉ
The biological characters of Sindbis virus strain of Yunnan(YN87448 strain) were studied by the test of the filtration, acid-resistant, ether-resistant, CPE, susceptibility of animal, HA, plague, determination of virus titres, and the cross-HI, cross-IFAT and PRNT as well.The results indicated that YN87448 strain belongs to Sindbis virus, Alphavirus, Togaviridae. YN87448 strain virus was plaque purified(PYN87448). The biological character of PYN87448 strain virus was studied too. PYN87448 strain virus will be used in the molecule biological test.