Interleukin‐1 and interleukin‐8 in nicotine‐ and lipopolysaccharide‐exposed gingival keratinocyte cultures

Johnson GK, Guthmiller JM, Joly S, Organ CC, Dawson DV. Interleukin‐1 and interleukin‐8 in nicotine‐ and lipopolysaccharide‐exposed gingival keratinocyte cultures. J Periodont Res 2010; 45: 583–588. © 2010 John Wiley & Sons A/S Background and Objective: Tobacco use is associated with increased periodontal destruction in both cigarette smokers and smokeless tobacco users. Gingival keratinocytes are the first cells in contact with microbial and tobacco components and play a key role in the innate immune response to these agents. The objective of this study was to evaluate the effect of nicotine and bacterial lipopolysaccharide (LPS) alone and in combination on gingival keratinocyte production of interleukin‐1α (IL‐1α) and interleukin‐8 (IL‐8). Material and Methods: Gingival keratinocyte cultures were established from 10 healthy, non‐tobacco‐using subjects. The cells were stimulated for 24 h with 1 μm or 1 mm nicotine and/or 10 μg/mL Escherichia coli or Porphyromonas gingivalis LPS. Interleukin‐1α and IL‐8 proteins were quantified using ELISAs. Results: Compared with untreated cultures, 1 mm nicotine stimulated production of IL‐1α (p < 0.001); E. coli and P. gingivalis LPS increased IL‐8 production (p = 0.0014 and p = 0.0232, respectively). A combination of nicotine and LPS produced the highest cytokine quantities. Amounts of IL‐1α and IL‐8 following 1 mm nicotine and LPS exposure were significantly greater than in untreated cultures (p < 0.001). Interleukin‐8 was also responsive to 0.1 μm nicotine combined with E. coli or P. gingivalis LPS compared with control cultures (p < 0.0001 and p = 0.0029, respectively). Both cytokines tended to be elevated following the combined treatment relative to nicotine or LPS treatment alone. Conclusion: These results demonstrate that nicotine and LPS differentially regulate IL‐1 and IL‐8 production by gingival keratinocytes. Combined treatment tended to elevate cytokine production further, which may have implications for the progression of periodontitis in tobacco users.     

Tissue reactions and sealing properties of Tubulitec® and Dropsin®

abstract – Pulpal reactions from the lining materials Tubulitec® and Dropsin® were tested on 109 monkey and 34 human teeth. Both lining materials showed slight, pulpal reactions in monkey teeth, i. e. minor changes in the odontoblast-predentin region, a little more pronounced for Dropsin. The human teeth revealed very few and mild responses to the lining materials. Twenty-five monkey teeth were employed for the penetration studies. None of the lining materials prevented penetration of AgNO₃ solution totally when placed in the lined cavities for five minutes.     

Attenuation of radiation‐ and chemoradiation‐induced mucositis using gamma‐d‐glutamyl‐l‐tryptophan (SCV‐07)

Oral Diseases (2010) 16 , 655–660 Objective: To evaluate the efficacy of a novel immunomodulating peptide (SCV‐07) in attenuating the course of radiation‐induced mucositis in an established animal model of oral mucositis (OM). Material and Methods: In three separate experiments, golden Syrian hamsters received either an acute radiation challenge to the buccal mucosa of eight fractionated doses of 7.5 Gy of radiation over a 2‐week‐period, or a combination of acute radiation and cisplatin. In each experiment, animals were treated with varying doses or schedules of SCV‐07 or placebo. OM was scored in a blinded fashion using digital images obtained during the experimental period. Results: We found that SCV‐07 reduced the severity and duration of both acute and fractionated radiation‐induced OM. Similarly, when radiation and chemotherapy were used to induce OM, treatment with SCV‐07 significantly reduced the duration of ulcerative OM. The therapeutic benefit was dependent on both dose and schedule of administration. Conclusion: Taken together, we found SCV‐07 was able to modify the duration and severity of oral mucositis and was dependent on schedule and dose.     

Eosinophilic sialodochitis: redefinition of ‘allergic parotitis’ and ‘sialodochitis fibrinosa’

Sialodochitis fibrinosa and allergic parotitis have described rare patients with recurrent salivary gland swelling and mucus plugs, often with atopy. We have evaluated three patients with atopic disease, recurrent salivary gland swelling, and an eosinophilic sialodochitis. Two had eosinophil‐rich mucus plugs. Fifty‐six additional cases were identified in a medical literature database search, each defined by recurrent salivary gland swelling associated with eosinophil‐rich mucus plugs or sialodochitis with periductal eosinophilic infiltration. The majority (78%) were reported from Japan. Females were predominantly affected (F:M = 2.3) with a median age of 47 years at evaluation. The parotid and submandibular glands were involved, respectively, in 71% and 46%. Allergic symptoms were present in 66%, atopic disease in 63% of those with reported allergy testing, and blood eosinophilia in 71%. Contrast sialography and other imaging modalities documented ductal dilatation in 82%. Treatments included anti‐allergic medications (58%), systemic glucocorticoids (25%), duct cannulation with irrigation, steroid injection, and/or duct dilatation (36%), and glandular resection (19%). We recommend the diagnosis ‘eosinophilic sialodochitis’ be applied to patients who meet this case definition. The disease is a unique cause of chronic recurrent salivary gland swelling. Its likely allergic etiology may be amenable to current or future biologic therapies.     

A fast Look–Locker method for <Emphasis Type="Italic">T</Emphasis><Subscript>1</Subscript> mapping of the head and neck region

Objective  A sequence for T ₁ relaxation time measurements that allows a high-resolution image to be obtained within a short acquisition time is described. Its application to the orofacial region is investigated. Methods  The sequence is based on the Look–Locker (LL) method and employs a magnetization-preparation pulse prior to data acquisition, with either a turbo-field echo (TFE) or turbo-field echo echo-planar imaging (TFEPI) sequence. We applied the multiple LL sequence by synchronizing the data acquisition with the virtual electrocardiogram. T ₁ results from the LL sequence were compared with those from the inversion recovery (IR) sequence. In an in vitro study, we evaluated the T ₁ maps of contrast medium at different concentrations. In an in vivo study, we evaluated the T ₁ maps in seven volunteers. Results  In the in vitro study, the correlation between the T ₁ values obtained from the LL sequence and those from the IR sequence was high, with an R ² of more than 0.99. For T ₁ values between 200 and 1,500 ms, the difference between the two methods was less than 7%. In the in vivo study, a high correlation was observed between the T ₁ values from the IR sequence and those from the LL sequence. The scan duration for the LL sequence was less than 3 min. Conclusion  Our method, based on the LL sequence, was found to be clinically useful for producing a T ₁ map.     

“MTA”—An Hydraulic Silicate Cement: Review update and setting reaction

Objectives

To review the current status and understanding of Portland cement-like endodontic materials commonly referred to by the trade designation “MTA” (alias “Mineral Trioxide Aggregate”), and to present an outline setting reaction scheme, hitherto unattempted.

Method

The literature was searched using on-line tools, overlapping an earlier substantial review to pick up any omissions, including that in respect of ordinary Portland cement (OPC), with which MTA shares much. The search was conducted for the period January 2005 to December 2009 using ‘MTA’, ‘GMTA’, ‘WMTA’, and ‘mineral AND trioxide AND aggregate’ as keywords, with various on-line search engines including ScienceDirect (http://www.sciencedirect.com), SAGE Journals Online (http://online.sagepub.com), Wiley Online Library (http://onlinelibrary.wiley.com), SciELO Scientific electronic library online (http://www.scielo.br/scielo.php), JSTOR (http://www.jstor.org), and Scopus (http://www.scopus.com). References of articles found were cross-checked where appropriate for missed publications. Manufacturers’ and related websites were searched with Google Search (http://www.google.com.hk).

Results

A generic name for this class of materials, Hydraulic Silicate Cement (HSC), is proposed, and an outline reaction scheme has been deduced. HSC has distinct advantages apparent, including sealing, sterilizing, mineralizing, dentinogenic and osteogenic capacities, which research continues to demonstrate. However, ad hoc modifications have little supporting justification.

Significance

While HSC has a definite place in dentistry, with few of the drawbacks associated with other materials, some improvements in handling and other properties are highly desirable, as are studies of the mechanisms of the several beneficial physiological effects. Reference to the extensive, but complex, literature on OPC may provide the necessary insight.     

Reliability and Failure Modes of Implant‐Supported Y‐TZP and MCR Three‐Unit Bridges

Purpose: Chipping within veneering porcelain has resulted in high clinical failure rates for implant‐supported zirconia (yttria‐tetragonal zirconia polycrystals [Y‐TZP]) bridges. This study evaluated the reliability and failure modes of mouth‐motion step‐stress fatigued implant‐supported Y‐TZP versus palladium‐silver alloy (PdAg) three‐unit bridges. Materials and Methods: Implant‐abutment replicas were embedded in polymethylmethacrylate resin. Y‐TZP and PdAg frameworks, of similar design (n = 21 each), were fabricated, veneered, cemented (n = 3 each), and Hertzian contact‐tested to obtain ultimate failure load. In each framework group, 18 specimens were distributed across three step‐stress profiles and mouth‐motion cyclically loaded according to the profile on the lingual slope of the buccal cusp of the pontic. Results: PdAg failures included competing flexural cracking at abutment and/or connector area and chipping, whereas Y‐TZP presented predominantly cohesive failure within veneering porcelain. Including all failure modes, the reliability (two‐sided at 90% confidence intervals) for a “mission” of 50,000 and 100,000 cycles at 300 N load was determined (Alta Pro, Reliasoft, Tucson, AZ, USA). No difference in reliability was observed between groups for a mission of 50,000. Reliability remained unchanged for a mission of 100,000 for PdAg, but significantly decreased for Y‐TZP. Conclusions: Higher reliability was found for PdAg for a mission of 100,000 cycles at 300 N. Failure modes differed between materials.     

Cloning and expression of α‐d‐glucosidase and N‐acetyl‐β‐glucosaminidase from the periodontal pathogen,Tannerella forsythensis (Bacteroides forsythus)

Screening a genomic library of Tannerella forsythensis (Bacteroides forsythus), using synthetic substrates conjugated to a fluorogen, 4‐methylumbelliferone identified two glycosidase genes, which encode α‐d ‐glucosidase and N‐acetyl‐β‐d ‐glucosaminidase, respectively. The α‐d ‐glucosidase has a M_r of 81,141 and is homologous to an α‐d ‐glucosidase from Bacteroidesthetaiotaomicron. The N‐acetyl‐β‐d ‐glucosaminidase has a M_r of 87,787 and is homologous to an N‐acetyl‐β‐d ‐glucosaminidase in Porphyromonasgingivalis W83.