| 3681. |
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| 3682. |
- Van de Bovenkamp, Jeroen H, et al.
(författare)
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The MUC5AC glycoprotein is the primary receptor for Helicobacter pylori in the human stomach
- 2003
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Ingår i: Helicobacter. - : Wiley. - 1083-4389 .- 1523-5378. ; 8:5, s. 521-532
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Tidskriftsartikel (refereegranskat)abstract
- Background and objectives. Helicobacter pylori shows a characteristic tropism for the mucusproducing gastric epithelium. In infected patients, H. pylori colocalizes in situ with the gastric secretory mucin MUC5AC. The carbohydrate blood-group antigen Lewis B (LeB) was deemed responsible for the adherence of H. pylori to the gastric surface epithelium. We sought to determine if MUC5AC is the carrier of LeB, and thus if MUC5AC is the underlying gene product functioning as the main receptor for H. pylori in the stomach. Methods. We studied three types of human tissue producing MUC5AC: Barrett’s esophagus (BE), normal gastric tissue, and gastric metaplasia of the duodenum (GMD). Tissue sections were immunofluorescently stained for MUC5AC or LeB, and subsequently incubated with one of three strains of Texas red-labeled H. pylori , one of which was unable to bind to LeB. We determined the colocalization of MUC5AC or LeB with adherent H. pylori. Results. The binding patterns for the two LeBbinding strains to all tissues were similar, whereas the strain unable to bind to LeB did not bind to any of the tissues. In normal gastric tissue, the LeBbinding strains always bound to MUC5AC- and LeBpositive epithelial cells. In four nonsecretor patients, colocalization of the LeB-binding strains was found to MUC5AC-positive gastric epithelial cells. In BE, the LeB-binding H. pylori strains colocalized very specifically to MUC5AC-positive cells. MUC5ACproducing cells in GMD contained LeB. Yet, LeBbinding H. pylori not only colocalized to MUC5AC or LeB present in GMD, but also bound to the LeBpositive brush border of normal duodenal epithelium. Conclusions. Mucin MUC5AC is the most important carrier of the LeB carbohydrate structure in normal gastric tissue and forms the major receptor for H. pylori.
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| 3683. |
- Van der Burght, A S A M, et al.
(författare)
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Structure dependent induction of CYP1A by polychlorinated biphenyls in hepatocytes of male castrated pigs
- 2000
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Ingår i: Chemosphere. ; 41:10, s. 1697-1708
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Tidskriftsartikel (refereegranskat)abstract
- Hepatocytes cultures prepared from castrated pig hepatocytes (Great YorkshirexDutch Landrace), as a model for human liver, were used to study the effect of twenty polychlorinated biphenyls (PCBs) on CYP1A activity, measured as the dealkylation of either ethoxyresorufin or methoxyresorufin. The selection of the PCBs was based on their differences in physico-chemical properties. The non-ortho and mono-ortho substituted PCBs were the most potent CYP1A inducers in pig hepatocytes. In addition, several multiple-ortho substituted congeners, with five or more chlorine atoms, were inducers of CYP1A activity as well. Their relative effect potencies (REP) were proximately 10,000 times lower than the most potent congener, 3,3',4,4',5 PeCB (PCB#126). Using partial least-squares (PLS) modeling, predictions of CYP1A activity could be made for all tetra to hepta substituted congeners. Several multiple-ortho substituted PCBs, which are highly abundant in the biotic and abiotic environment, have been found to induce CYP1A activity in pig hepatocytes. Because induction of CYP1A activity is used as biomarker for Ah-receptor mediated responses, it is suggested to include these congeners in future risk assessment.
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| 3684. |
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| 3685. |
- van Dijken, Jan
(författare)
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A 6-year clinical evaluation of Class I poly-acid modified resin composite/resin composite laminate restorations cured with a two-step curing technique.
- 2003
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Ingår i: Dental Materials. - 0109-5641 .- 1879-0097. ; 19:5, s. 423-428
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Polymerization shrinkage is still one of the main disadvantages of resin composite restorations (RC). Especially in cavities with a high C-factor, debonding can occur. A laminate restoration including a base with a more elastic behavior might result in a better adaptation. The purpose of this study was to evaluate the durability of a combination of two techniques suggested to counter the stress formation in direct RC restorations in cavities with the highest C-factor. METHODS: Each of the 29 patients received one or two pair(s) of Class I restorations. The first restoration was a poly-acid modified resin composite/resin composite (PMRC/RC) sandwich restoration and the second a direct RC restoration. Both restorations, except for the PMRC layer, were placed with oblique layering and two-step curing technique. Ninety restorations, 23 premolar and 67 molars, were evaluated annually with slightly modified USPHS criteria during 6 years. RESULTS: At 6 years, 41 pairs were evaluated. A cumulative failure rate of 2.4% was observed for both the RC and the laminate restorations. One laminate restoration showed non-acceptable color match, but was not replaced and one RC restoration showed non-acceptable marginal adaptation. Two cases of slight postoperative sensitivity were observed in one patient. Three restorations were partially replaced due to primary proximal caries. SIGNIFICANCE: A high durability for and no differences, were observed between both restorative techniques in Class I cavities.
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| 3686. |
- van Dijken, Jan
(författare)
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Durability of three simplified adhesive systems in Class V non-carious cervical dentin lesions.
- 2004
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Ingår i: American Journal of Dentistry. - 0894-8275. ; 17:1, s. 27-82
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To investigate the durability of three simplified systems in Class V non-carious abrasion/erosion lesions. METHODS: 144 non-carious cervical dentin lesions were restored either with Clearfil Liner Bond 2, a 2-step self-etching primer (n = 46), One Coat Bond, a one bottle total-etch system applied with one coat (n = 46), or Prompt-L-Pop, a 1-step self-etching primer ("all-in-one") (n = 52), in 90 individuals. Ninety-eight of the lesions showed sclerotic dentin and 46 were non-sclerotic. Sixty-one were slightly roughened with a diamond bur before conditioning. The restorations were evaluated every 6 months during a 2-year period with slightly modified USPHS criteria. RESULTS: All except three restorations were evaluated over 2 years. The cumulative loss rates for Clearfil Liner Bond 2, One Coat Bond and Prompt-L-Pop were at 6 months: 4.3, 2.2 and 3.9%, at 18 months: 4.3, 10.9 and 15.4% and at 24 months: 8.7, 13.0 and 21.2%, respectively. The cumulative loss rates of the materials in sclerotic lesions (15.7%) versus non-sclerotic lesions (14.0%) were not significanty different. Restorations placed with a diamond bur-roughened lesions showed a loss rate of 14.5%, while for the non-roughened lesions the frequency was 14.8%.
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| 3687. |
- van Dijken, Jan
(författare)
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Resin-modified glass ionomer cement and self-cured resin composite luted ceramic inlays. A 5-year clinical evaluation.
- 2003
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Ingår i: Dental Materials. - 0109-5641 .- 1879-0097. ; 19:7, s. 670-674
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: This study evaluated IPS Empress ceramic inlays luted with two chemical-cured luting agents, a resin-modified glass ionomer cement (Fuji Plus (F)) and a resin composite (RC) (Panavia 21 (P)). METHODS: Seventy-nine ceramic inlays were placed in Class II cavities in 29 patients. At least two inlays were placed in each patient to compare the luting techniques intra-individually. In each patient half of the inlays were luted with F and the other half with P. The inlays were evaluated clinically, according to modified USPHS criteria (van Dijken, 1986), at baseline, after 6 months, and yearly during 5 years. RESULTS: At 5 years, 71 inlays were evaluated. Two small partial fractures were observed at 3 years (1P, 1F). One inlay showed recurrent root caries at 4 years (P). Four inlays, two in each group showed non-acceptable color match (2P, 2F). Small defects were observed in 4 inlays (2P, 2F). A slight ditching of the cement margins was observed in both luting groups but did not seem to increase during the second half of the evaluation. No significant difference in durability was observed between the two luting agents. SIGNIFICANCE: IPS Empress inlays luted with the chemical-cured RC and the resin-modified glass ionomer cement functioned satisfactory during the 5 years follow-up.
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| 3688. |
- van Dijken, Jan Wv, et al.
(författare)
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A calcium aluminate cement as restorative material in Class V cavities.
- 2004
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Ingår i: Swedish Dental Journal. - 0347-9994. ; 28:3, s. 111-8
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Tidskriftsartikel (refereegranskat)abstract
- Recently a calcium aluminate cement (Doxa Certex, Uppsala, Sweden) has been developed intended to be used as direct restorative filling material.The aim of this study was to evaluate intra-individually the experimental calcium aluminate cement (CAC) and a resin composite (RC;Tetric Ceram) in Class V restorations. Each of 46 participants received at least one pair of restorations of the same size, one CAC and one RC.The 119 restorations were evaluated clinically, according to slightly modified USPHS criteria, at baseline, after 6 mths, 1, 2 and 3 yrs. None of the patients reported post-operative sensitivity. At 3 yrs, 111 restorations were evaluated. Significantly better clinical durability was shown for RC.Two non-acceptable CAC restorations were observed at 6 months, 3 CAC and 1 RC at 12 months, 5 CAC and 2 RC at 24 months, and 8 CAC at 36 months.This resulted in a cumulative failure frequency of 32% for the CAC material and 5% for the RC material. Main reason for failure for the CAC was total or partial lost restorations, and for the RC lost restorations. It can be concluded that the CAC showed a non-acceptable clinical failure rate for Class V restorations.
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| 3689. |
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| 3690. |
- van Noort, R, et al.
(författare)
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An overview of the current status of national reporting systems for adverse reactions to dental materials.
- 2004
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Ingår i: Journal of Dentistry. - : Elsevier BV. - 0300-5712 .- 1879-176X. ; 32:5, s. 351-358
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Since all dental materials pose a potential risk to patients and members of the dental team, the post-market monitoring of adverse reactions caused by dental materials should be considered essential. This article reviews the current status of post-market monitoring of adverse reactions to dental materials and highlights some of the issues that arise in trying to establish an evidence base on the characteristics of adverse reactions to dental materials. METHODS: Norway, Sweden and more recently the UK have sought to monitor adverse reactions to dental materials systematically and proactively in an effort to add to the evidence base on the safety of dental materials. Their experiences in undertaking post-market surveillance have been combined in preparing this article. RESULTS: To date the Norwegian, Swedish and the UK projects has received 1268 reports over 11 years, 848 reports over 5.5 years and 1117 reports over 3 years, respectively, relating to adverse reactions seen or experienced by dental personnel and patients. Presently, there are no harmonized criteria for what can be classified as an adverse reaction related to dental materials. Under reporting is a recognised problem and lack of awareness and lack of clarity as to what constitutes an adverse reaction may be contributory factors. A pro-active reporting system takes a considerable time to become established, but can generate a lot of potentially useful information. CONCLUSIONS: There is a need to raise the awareness among dental professionals of the potential for adverse reactions due to dental materials and to develop an internationally accepted system of data gathering that can produce the evidence that reflect the extent, severity and incidence of adverse reactions to dental materials.
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