The neutralising and stimulatory effects of antimicrobial peptide LL-37 in human gingival fibroblasts

OBJECTIVES

To investigate the effects of LL-37, a broad spectrum antimicrobial peptide expressed in periodontal tissues, on human gingival fibroblast responsiveness to microbial challenge and to explore the direct effects of LL-37 on human gingival fibroblasts.

DESIGN

The effect of LL-37 on bacterial lipopolysaccharide-induced expression of Interleukin (IL-6) and chemokine C-X-C motif ligand (CXCL) 8 was determined by enzyme linked immunosorbent assay (ELISA). LL-37's influence on bacterial lipopolysaccharide-induced IκBα degradation was investigated by western blot. DNA microarray analysis initially determined the direct effects of LL-37 on gene expression, these findings were subsequently confirmed by quantitative polymerase chain reaction and ELISA analysis of selected genes.

RESULTS

Bacterial lipopolysaccharide-induced IL-6 and CXCL8 production by human gingival fibroblasts was significantly reduced in the presence of LL-37 at concentrations in the range of 1-10 µg/ml. LL-37 led to a reduction in lipopolysaccharide-induced IκBα degradation by Escherichia coli lipopolysaccharide and Porphyromonas gingivalis lipopolysaccharide (10 µg/ml). LL-37 (50 µg/ml) significantly altered the gene expression of 367 genes in human gingival fibroblasts by at least 2-fold. CXCL1, CXCL2, CXCL3, Interleukin-24 (IL-24), CXCL8, Chemokine (C-C motif) Ligand 2, and Suppressor of Cytokine Signalling 3 mRNA were significantly upregulated by LL-37. LL-37 also significantly stimulated expression of CXCL8, hepatocyte growth factor and CXCL1 at the protein level.

CONCLUSION

LL-37 plays an important regulatory role in the immunomodulatory activity of gingival fibroblasts by inhibiting lipopolysaccharide -induced expression of inflammatory cytokines and directly stimulating the expression of an array of bioactive molecules involved in inflammation and repair.

A protocol for the Development of Core Outcome Sets for Endodontic Treatment modalities (COSET): an international consensus process

Background

The outcome of endodontic treatment is generally assessed using a range of patient and clinician-centred, non-standardised clinical and radiographic outcome measures. This makes it difficult to synthesise evidence for systematic analysis of the literature and the development of clinical guidelines. Core outcome sets (COS) represent a standardised list of outcomes that should be measured and reported in all clinical studies in a particular field. Recently, clinical researchers and guideline developers have focussed on the need for the integration of a patient-reported COS with clinician-centred measures. This study aims to develop a COS that includes both patient-reported outcomes and clinician-centred measures for various endodontic treatment modalities to be used in clinical research and practice.

Methods

To identify reported outcomes (including when and how they are measured), systematic reviews and their included clinical studies, which focus on the outcome of endodontic treatment and were published between 1990 and 2020 will be screened. The COSs will be defined by a consensus process involving key stakeholders using semi-structured interviews and an online Delphi methodology followed by an interactive virtual consensus meeting. A heterogeneous group of key ‘stakeholders’ including patients, general dental practitioners, endodontists, endodontic teachers, clinical researchers, students and policy-makers will be invited to participate. Patients will establish, via interactive interviews, which outcomes they value and feel should be included in a COS. In the Delphi process, other stakeholders will be asked to prioritise outcomes identified from the literature and patient interviews and will have the opportunity at the end of the first round to add outcomes that are not included, but which they consider relevant. Feedback will be provided in the second round, when participants will be asked to prioritise the list again. If consensus is reached, the remaining outcomes will be discussed at an online meeting and agreement established via defined consensus rules of outcome inclusion. If consensus is not reached after the second round, a third round will be conducted with feedback, followed by the online meeting. Following the identification of a COS, we will proceed to identify how and when these outcomes are measured.

Discussion

Using a rigorous methodology, the proposed consensus process aims to develop a COS for endodontic treatment that will be relevant to stakeholders. The results of the study will be shared with participants and COS users. To increase COS uptake, it will also be actively shared with clinical guideline developers, research funders and the editors of general dental and endodontology journals.

Trial registration

COMET 1879. 21 May 2021.

Odontoblast cell death induces NLRP3 inflammasome-dependent sterile inflammation and regulates dental pulp cell migration, proliferation and differentiation

AIM

To investigate the ability of dead odontoblasts to initiate NLRP3 inflammasome-dependent sterile inflammation and to explore the effect on dental pulp cell (DPCs) migration, proliferation and odontogenic differentiation.

METHODS

Odontoblast-like cells were subjected to freezing-thawing cycles to produce odontoblast necrotic cell lysate (ONCL). DPCs were treated with ONCL to assess proliferation and migration. THP-1 differentiated macrophages stimulated with ONCL and live cell imaging and western blotting were used to assess NLRP3 inflammasome activation. Cytokines were measured with multiplex arrays and ELISA. qPCR, alkaline phosphatase and Alizarin red assays were used to assess odontogenic differentiation of DPCs. Data were analysed using the t-test or anova followed by a Bonferroni post hoc test with the level of significance set at P ≤ 0.05.

RESULTS

ONCL induced migration and proliferation of DPCs. Treatment of THP-1 macrophages with ONCL resulted in the release of the inflammatory cytokines IL-1β, IL-6, IL-8, TNFα, IFN-γ, CCL2 and angiogenic growth factors, angiogenin and angiopoietin. This inflammatory response was associated with activation of NFκB, p38MAPK and NLRP3 inflammasome. To confirm that ONCL induced inflammatory response is NLRP3 inflammasome-dependent, treatment with a caspase-1 inhibitor and a specific NLRP3 inhibitor significantly reduced IL-1β release in THP-1 macrophages (P = 0.01 and 0.001). Inflammasome activation product, IL-1β, induced odontogenic differentiation of DPCS as evident by the increase in odontogenic genes expression DMP-1, RUNX-2, DSPP and SPP, alkaline phosphatase activity and mineralization.

CONCLUSION

Dead odontoblasts induced NLRP3 inflammasome-dependent sterile inflammation and activated the migration, proliferation and differentiation of DPCs.

Matrix Metalloproteinase-3 Differences in Oral and Skin Fibroblasts

While skin wounds heal by scarring, wounds of oral mucosa show privileged healing with minimal scar formation. Our hypothesis was that phenotypic differences between oral and skin fibroblasts underlie these differences in healing. The aims of this study were to compare MMP-3 expression by oral and skin fibroblasts and investigate a role for MMP-3 in mediating collagen gel contraction. Oral fibroblasts induced significantly greater gel contraction than did paired skin cells. Inhibition of MMP activity significantly inhibited gel contraction by both cell types. Specific inhibition of MMP-3 activity reduced gel contraction by oral, but not skin, fibroblasts. Oral fibroblasts produced significantly higher levels of MMP-3 than did skin fibroblasts at all levels studied. TGF-β1 and -β3 isoforms stimulated MMP-3 expression at mRNA, protein, and activity levels by both fibroblast populations. Results suggest that increased MMP-3 production by oral fibroblasts may underlie the differences in wound-healing outcome seen in skin and oral mucosa.

A secretory leukocyte protease inhibitor variant with improved activity against lung infection

Secretory leukocyte protease inhibitor (SLPI) is an important respiratory tract host defense protein, which is proteolytically inactivated by excessive neutrophil elastase (NE) during chronic Pseudomonas infection in the cystic fibrosis (CF) lung. We generated two putative NE-resistant variants of SLPI by site-directed mutagenesis, SLPI-A16G and SLPI-S15G-A16G, with a view to improving SLPI's proteolytic stability. Both variants showed enhanced resistance to degradation in the presence of excess NE as well as CF patient sputum compared with SLPI-wild type (SLPI-WT). The ability of both variants to bind bacterial lipopolysaccharides and interact with nuclear factor-κB DNA binding sites was also preserved. Finally, we demonstrate increased anti-inflammatory activity of the SLPI-A16G protein compared with SLPI-WT in a murine model of pulmonary Pseudomonas infection. This study demonstrates the increased stability of these SLPI variants compared with SLPI-WT and their therapeutic potential as a putative anti-inflammatory treatment for CF lung disease.

Dental pulp fibroblasts express neuropeptide Y Y1 receptor but not neuropeptide Y

AIM

To investigate whether dental pulp fibroblasts express neuropeptide Y (NPY) and NPY-Y1 in vitro and to determine the effects of the cytokines including interleukin-1β (IL-1β), TGF- β(1) , substance P and NPY on the expression of NPY Y1.

METHODOLOGY

Three primary fibroblast cell strains were obtained from freshly extracted human third molar teeth. RT-PCR was utilized to detect expression of NPY and mRNA expression. Membrane protein samples were isolated, and protein expression was determined by Western blotting. Radioimmunoassay was used to quantify NPY expression in healthy (n = 35) and carious (n = 39) whole pulp samples, and the student's t-test was used to test for statistical significance. In addition, the 3-(4,5-Dimethylthiazol,2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to assay fibroblast cell growth.

RESULTS

mRNA transcripts were found in all three fibroblast cell populations with the cytokines having a stimulatory effect on its expression (P < 0.05). NPY mRNA was not detected in the cell strains. NPY-Y1 receptor protein expression was visualized by Western blotting, and there was no effect of IL-1β or TGF- β(1) on its expression. The mean concentration of NPY-Ir determined by radioimmunoassay in non-carious teeth was 19.40 ng x g(-1) (±17.03 SD) compared to 29.95 ng x g(-1) (±20.99 SD) in carious teeth (P < 0.05).

CONCLUSION

Human dental pulp fibroblasts express, but do not synthesize, NPY, demonstrating that the fibroblast is a target cell for NPY. The effect of proinflammatory cytokines suggests that fibroblasts play a neuroimmunomodulatory role in the pulpal response to dental caries and injury.

PAR-2 regulates dental pulp inflammation associated with caries

Protease-activated receptors (PARs) are G-protein-coupled receptors that are activated enzymatically by proteolysis of an N-terminal domain. The cleavage and activation of PARs by serine proteases represent a novel mechanism by which such enzymes could influence the host inflammatory response. The aim of this study was to determine whether PAR-2 expression and activation were increased in dental caries. Using immunohistochemistry, we showed PAR-2 to be localized to pulp cells subjacent to caries lesions, but minimally expressed by healthy pulp tissue. Trypsin and the PAR-2 agonist (PAR2-AP) activated PAR-2 in an in vitro functional assay. Endogenous molecules present in pulp cell lysates from carious teeth specifically activated PAR-2, but those from healthy teeth failed to do so. The activation of PAR-2 in vitro was shown to increase the expression of the pro-inflammatory mediator cyclo-oxygenase-2 (COX-2), providing a mechanism whereby PAR-2 could modulate pulpal inflammation.

Neuropeptide Y Y1 receptor in human dental pulp cells of noncarious and carious teeth

AIM

To determine the distribution of the NPY Y1 receptor in carious and noncarious human dental pulp tissue using immunohistochemistry. A subsidiary aim was to confirm the presence of the NPY Y1 protein product in membrane fractions of dental pulp tissue from carious and noncarious teeth using western blotting.

METHODOLOGY

Twenty two dental pulp samples were collected from carious and noncarious extracted teeth. Ten samples were processed for immunohistochemistry using a specific antibody to the NPY Y1 receptor. Twelve samples were used to obtain membrane extracts which were electrophoresed, blotted onto nitrocellulose and probed with NPY Y1 receptor antibody. Kruskal-Wallis one-way analysis of variance was employed to test for overall statistical differences between NPY Y1 levels in noncarious, moderately carious and grossly carious teeth.

RESULTS

Neuropeptide Y Y1 receptor immunoreactivity was detected on the walls of blood vessels in pulp tissue from noncarious teeth. In carious teeth NPY Y1 immunoreactivity was observed on nerve fibres, blood vessels and inflammatory cells. Western blotting indicated the presence and confirmed the variability of NPY Y1 receptor protein expression in solubilised membrane preparations of human dental pulp tissue from carious and noncarious teeth.

CONCLUSIONS

Neuropeptide Y Y1 is expressed in human dental pulp tissue with evidence of increased expression in carious compared with noncarious teeth, suggesting a role for NPY Y1 in modulation of caries induced pulpal inflammation.

Detection of individual human neutrophil ?-defensins (human neutrophil peptides 1, 2 and 3) in unfractionated gingival crevicular fluid?A MALDI-MS approach

The role of antimicrobial peptides is particularly important in the oral cavity where there is constant challenge by microorganisms. The alpha-defensins are a group of cationic peptides that comprise 30-50% of the total protein in azurophilic granules of human neutrophils. They include the human neutrophil peptides (HNP) 1, 2 and 3 which have almost identical amino acid sequences but differ in their biological activities. The amino acid sequence similarities of the defensins have made it difficult to unequivocally determine the presence of individual defensins using antibody-based techniques. However, by virtue of their cationic nature we postulated that the defensins would fly particularly well in mass spectrometry and that this characteristic would allow facile identification of individual HNPs in unfractionated gingival crevicular fluid (GCF) from periodontitis patients and healthy controls. Although there was variability in levels of defensins detected in periodontal health and disease, HNP-1 was always identified as the major peak in the triad and HNP-3 as the minor peak, lending support to the hypothesis that HNP-2 may arise by post-translational proteoyltic cleavage of HNP-3 rather than HNP-1. The finding that the defensins were more abundant in a higher proportion of the healthy sites studied could be linked to a more intact defensin barrier in periodontal health.

Sjögren’s syndrome: a condition with features of chronic graft-versus-host disease: does duct cell adhesion or permeability play a role in pathogenesis?

Primary and Secondary Sjögren's syndrome are disease complexes characterized by periductal inflammatory cell infiltration of the salivary and lacrimal glands and manifest as dry mouth and dry eyes. Secondary Sjögren's syndrome may be associated with a connective tissue disorder. Additional extraglandular features in Sjögren's syndrome include a generalized inflammatory exocrinopathy that might be associated with abnormalities of both humoral and cellular mediated immunity. Similar inflammatory changes and extraglandular features, including an altered immune response, have been reported in patients developing graft-versus-host disease after bone-marrow transplantation and in patients with primary biliary cirrhosis. The periductal nature of the inflammatory response involving minor salivary and other glands raises the possibility of altered duct cell adhesion or permeability in playing a role in the aetiopathogenesis of Sjögren's syndrome. The paper pulls together evidence that could be interpreted in this light. Evidence for bacterial or viral factor(s) altering the antigenicity of the histocompartibility (HC) complex on ductal cells in Sjögren's syndrome patients is also described. A hypothesis is proposed for Sjögren's syndrome in which the principal feature is an alteration in salivary gland duct cell adhesion or permeability. A re-evaluation of current knowledge of these two conditions from a clinical and experimental context are interpreted in this light.

Extraction and radioimmunoassay quantitation of neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) from human dental pulp tissue

The measurement of neuropeptides in complex biological tissue samples requires efficient and appropriate extraction methods so that immunoreactivity is retained for subsequent radioimmunoassay detection. Since neuropeptides differ in their molecular mass, charge and hydrophobicity, no single method will suffice for the optimal extraction of various neuropeptides. In this study, dental pulp tissue was obtained from 30 human non-carious teeth. Of the three different neuropeptide extraction methods employed, boiling in acetic acid in the presence of protease inhibitors yielded the highest levels of neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP). High pressure liquid chromatography (HPLC) analysis of dental pulp tissue verified the authenticity of the neuropeptides extracted.

Quantitative analysis of substance P, neurokinin A and calcitonin gene-related peptide in pulp tissue from painful and healthy human teeth

AIM

The purpose of this study was to investigate the levels of substance P (SP), neurokinin A (NKA) and calcitonin gene-related peptide (CGRP) in painful and healthy human dental pulps.

METHODOLOGY

Forty-six samples of pulp tissue were collected from extracted or endodontically treated painful teeth and 20 from clinically healthy teeth extracted for orthodontic reasons. All pulp samples were boiled in 0.5 m acetic acid for 10 min, centrifuged and the supernatant collected. SP, NKA and CGRP levels were measured using radioimmunoassay.

RESULTS

Substance P and CGRP were present in all samples and NKA was detected in 96% of the pulps. CGRP was present in much higher concentrations than SP and NKA in both painful and non-painful teeth. The painful teeth had significantly higher concentrations of SP (P = 0.02), NKA (P < 0.001) and CGRP (P = 0.03) than non-painful teeth. The concentration of CGRP was significantly higher in the pulps of smokers compared with non-smokers (P = 0.02).

CONCLUSIONS

Elevated levels of these neuropeptides in pulps from painful teeth indicate that they may play an important role in the process of pulpal inflammation and pain. Further investigation of the association between these neuropeptides and pulpal status may help to improve our understanding of pulpal inflammation and dental pain.

Quantitative analysis of MRP-8 in gingival crevicular fluid in periodontal health and disease using microbore HPLC

BACKGROUND

The protein components of GCF can be separated by reverse-phase microbore HPLC on a C18 column with detection on the basis of 214 nm absorbance. A single major symmetrical protein peak eluting with a retention time of 26 min (50% acetonitrile) was evident in gingival crevicular fluid (GCF) from periodontitis patients but not in healthy GCF. This protein was identified as human MRP-8 by N-terminal amino acid sequencing and liquid chromatography quadropole mass spectrometry.

AIMS

To quantify the amount of MRP-8 detectable in GCF from individual healthy, gingivitis and periodontitis affected sites and to study the relationship, if any, between the levels of this responsive protein and periodontal health and disease.

METHODS

GCF was sampled (30 s) from healthy, gingivitis, and periodontitis sites in peridontitis subjects (n=15) and from controls (n=5) with clinically healthy gingiva and no periodontitis. Purified MRP-8 was sequenced by Edmann degradation and the phenylthiohydantoin (PTH) amino acid yield determined (by comparison of peak area with external PTH amino acid standards). This value was subsequently used to calculate the relative amount of protein in the peak eluting with a retention time of 26.0 min (MRP-8) in individual GCF chromatograms.

RESULTS

Higher levels of MRP-8 were detected in inflammatory sites: periodontitis 457.0 (281.0) ng; gingivitis 413.5 (394.5) ng compared with periodontally healthy sites in diseased subjects 14.6 (14.3) ng and in controls 18.6 (18.5) ng, p=0.003. There was at least 20-fold more MRP-8 in the inflammatory compared with the healthy sites studied.

CONCLUSIONS

The preliminary data indicate that MRP-8 is present in GCF, with significantly greater amounts present at diseased than healthy sites. A systematic study of the relationship of this protein to periodontal disease could prove useful in further clarifying whether MRP-8 could be a reliable GCF biomarker of gingivitis and periodontitis.

Identification of MRP-8 (calgranulin A) as a major responsive protein in chronic periodontitis

The purpose of the study was to analyse how the protein composition of the inflammatory exudate associated with chronic periodontitis differed from the exudate in periodontal health. Gingival crevicular fluid (GCF) was collected from sites with chronic periodontal inflammation and from non-diseased sites in healthy control subjects. Microbore HPLC analysis revealed one major difference in GCF protein profiles between healthy controls and periodontitis patients. The protein enhanced in periodontitis patients was identified as migration inhibitory factor-related protein-8 (MRP-8) by a combination of N-terminal amino acid sequencing, mass spectrometry, and SDS-PAGE. Together, these data demonstrate, for the first time, the presence of monomeric MRP-8 in an inflammatory exudate. Whether monomeric MRP-8 is a unique feature of chronic periodontal inflammation is not yet clear, but the chemotactic properties of this peptide support a functional role for MRP-8 in periodontal inflammation.

Bcl-2 expression in sequential biopsies of potentially malignant oral mucosal lesions assessed by immunocytochemistry

OBJECTIVE

To examine, for the first time Bcl-2 expression in sequential (autogenous) oral mucosal biopsies taken from the same sites in a gender, risk-factor matched, Caucasoid sample, over a 21-year period.

DESIGN

Retrospective immunocytochemical longitudinal study of archival serial biopsies.

MATERIALS AND METHODS

Computer records were used to identify biopsy specimens derived from 12 patients. These were divided into four groups: (1) Histologically innocuous lesions which remained histologically innocuous. (2) Dysplastic lesions which remained dysplastic. (3) Histologically innocuous lesions which later progressed to squamous cell carcinoma (SCC). (4) Dysplastic lesions which later progressed to SCC. This represented 65 biopsies in total. Bcl-2 expression was studied using mouse antihuman BCL-2 oncoprotein clone 124 (Dako, Denmark).

RESULTS

Generally, there was a lack of Bcl-2 immunoreactivity in the epithelium, with one exception in dysplastic epithelium from a group (3) patient.

CONCLUSION

These findings suggest that in our series, Bcl-2 is not expressed early in oral premalignant lesions and appears to contradict previous reports. Possible explanations for this disparity are considered.

Carboxypeptidase-mediated metabolism of calcitonin gene-related peptide in human gingival crevicular fluid--a rôle in periodontal inflammation?

BACKGROUND

Metabolism by peptidases plays an important rôle in modulating the levels of biologically-active neuropeptides. The metabolism of the anti-inflammatory neuropeptide calcitonin gene-related peptide (GCRP), but not the pro-inflammatory neuropeptides substance P (SP) and neurokinin A (NKA) by components of the gingival crevicular fluid (GCF), could potentiate the inflammatory process in periodontitis.

AIMS

To characterise the extracellular hydrolysis of CGRP as a mechanism for the selective inactivation of this neuropeptide in GCF from periodontitis sites.

METHODS

Samples of GCF from periodontitis patients and periodontally-healthy subjects were incubated with synthetic human SP, NKA or CGRP. Reaction between the GCF constituents and synthetic peptides was allowed to progress from 0-180 min. Results of neuropeptide metabolism at each time were analysed by matrix-assisted laser desorption/ionisation mass spectrometry.

RESULTS

There was no evidence of metabolism of SP, NKA or CGRP by constituents of healthy GCF. Metabolism of synthetic SP and NKA was minimal even after extensive incubation with periodontitis GCF. However, loss of carboxy-terminal amino acids was evident after only 1 min incubation with periodontitis GCF. The pattern of CGRP metabolism, which proceeded from the C-terminus, indicated that the neuropeptide was degraded by a carboxypeptidase. After 180 min, there was extensive carboxypeptidase degradation of CGRP to an 11 amino acid peptide.

CONCLUSIONS

It is concluded that carboxypeptidase activity in GCF from periodontitis patients is responsible for rapid breakdown of CGRP but not SP or NKA. The rapid action of this carboxypeptidase on the anti-inflammatory neuropeptide CGRP is suggestive of a pathophysiological rôle for the enzyme in selectively degrading CGRP, thereby potentiating periodontal inflammation.

Changes in substance P and neurokinin A in gingival crevicular fluid in response to periodontal treatment

BACKGROUND

The study of periodontitis provides a unique model for assessing the involvement of neuropeptides in inflammatory disease.

AIM

To investigate the effects of periodontal treatment, resulting in a return to periodontal health, on the levels of substance P (SP) and neurokinin A (NKA) in gingival crevicular fluid (GCF).

METHOD

We completed a cause of non-surgical treatment for 8 subjects with periodontitis (6 females 2 males, mean age 45.1, range 38-67 years) started a course of non-surgical periodontal treatment. Clinical indices were measured at 2 periodontitis sites at the initial visit and at 8 weeks after the completion of treatment in each subject. A 30-s sample of GCF was collected from each test site using perio paper strips. Each strip was placed into 500 microl of ice cold 0.1 M PBS, pH 7.4, vortex mixed for 30 s, and then stored at -70 degrees C until analysed by radioimmunoassay.

RESULTS

The clinical condition of all test sites improved as a result of the periodontal treatment. The levels (pg/30 s sample) of SP fell from 56.3 (SD 66.0) at the initial visit to 4.2 (3.1) after treatment, p=0.017. The concentration (pg/microl) of SP in GCF fell from 140.6 (175.6) to 24.2 (11.1), p=0.036. The levels of NKA fell from 30.5 (17.1) to 10.6 (4.9), p=0.012 whereas the concentration changed little from 85.4 (43.5) to 61.6 (15.1), p=0.41.

CONCLUSION

The reduction in inflammation resulting from effective periodontal treatment is associated with a reduction in the levels of tachykinins in gingival crevicular fluid.

A comparison of four extraction methods for substance P, neurokinin A and calcitonin gene-related peptide from human dental pulp tissue

Measuring neuropeptides in biological tissues by radioimmunoassay requires efficient extraction that maintains their immunoreactivity. Many different methods for extraction have been described, but there is little information on optimal extraction methods for individual neuropeptides from human dental pulp tissue. The aim was therefore to identify an effective extraction procedure for three pulpal neuropeptides; substance P, neurokinin A and calcitonin gene-related peptide. Tissue was obtained from 20 pulps taken from teeth freshly extracted for orthodontic reasons. The pulp samples were divided into four equal groups and different extraction methods were used for each group. Boiling whole pulp in acetic acid gave the highest overall yield and, in addition, offered an easy and rapid means of pulp tissue processing. The use of protease inhibitors did not increase the recovery of the immunoreactive neuropeptides but did provide the best combination of maximal recoveries and minimal variability. These results should be useful for planning the extraction of these neuropeptides from human pulp tissue in future studies.

An antibody-lectin sandwich assay for quantifying protein glycoforms

We describe an antibody-lectin sandwich assay for quantitation of glycoforms of proteins. The assay uses deglycosylated IgG antibody immobilized on a microtiter plate to capture the protein of interest from the sample. The particular glycoform is then identified by reaction with biotin-labeled lectin, which is measured using streptavidin/alkaline phosphatase. The assay can be adapted to quantitate any protein's glycoforms by simply substituting the antibody and lectin with specific alternatives.

Calcitonin gene-related peptide in gingival crevicular fluid in periodontal health and disease

The aims of the present study were to investigate whether calcitonin gene-related peptide (CGRP) was present in gingival crevicular fluid in both periodontal health and disease and to study the relationship with periodontal inflammation. Gingival crevicular fluid (GCF) was collected from a healthy, a gingivitis and a periodontitis site in 18 subjects with periodontitis and from a healthy site in 19 subjects without periodontitis. The volume of GCF was measured and each sample subsequently analysed for CGRP by radioimmunoassay. In subjects with periodontitis, CGRP immunoreactivity (CGRP-IR) was not detected in any periodontitis sites, nor in 67% of gingivitis and 28% of periodontally-healthy sites. The total amount of CGRP-IR was significantly elevated in periodontally healthy (p=0.0015) and gingivitis (p=0.027) compared with periodontitis sites. CGRP-IR was present in 89% of the healthy sites sampled in control subjects at comparable levels to those in healthy sites in periodontitis subjects. It is concluded that in periodontal inflammation, particularly in deep pockets, constituents of GCF process and degrade CGRP.

TFF1 gene expression in human medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is an uncommon tumour of calcitonin-secreting C-cells of the thyroid gland. This cancer represents an important potential model for the study of mechanisms of human epithelial cell transformation. Although recent studies have identified the gene involved in familial forms of MTC, little is known about the molecular pathogenesis of the sporadic variants of this tumour. The biological and prognostic significance of TFF1 expression, particularly in diverse human malignancies, suggests that the TFF1 protein could have a role in human neoplasia. Furthermore, in prostate cancer it has been demonstrated that TFF1 expression is closely associated with premalignant changes and neuroendocrine differentiation. In the present study, the expression of TFF1 was analysed in 18 human MTCs, comprising sporadic and familial tumours, C-cell hyperplasia, and one case of lymph gland metastasis. TFF1 expression was also examined in the cultures of a human MTC-derived tumour cell line (TT cell line). The results showed that ten sporadic tumours, three hereditary tumours (including C-cell hyperplasia), and one lymph gland metastasis displayed TFF1 immunoreactivity. Indirect fluorescence immunocytochemistry and Western blotting revealed that the TFF1 protein was strongly expressed in the TT cells. Northern analysis revealed that tumours and TT cells expressed the TFF1 transcript. Although the function of TFF1 protein in the carcinogenesis of MTC remains to be elucidated, its expression in the majority of cases of both sporadic and hereditary tumours, metastatic tumours, and in C-cell hyperplasia suggests that it may contribute to the pathogenesis of MTC.

Substance P and neurokinin A in gingival crevicular fluid in periodontal health and disease

The aims of the present study were to investigate whether the tachykinins substance P and neurokinin A were present in gingival crevicular fluid in both periodontal health and disease and to study the relationship with periodontal inflammation. Gingival crevicular fluid (GCF) was collected from a healthy, a gingivitis and a periodontitis site in 20 subjects with periodontitis and from a healthy site in 20 subjects without periodontitis. The volume of GCF was measured and each sample subsequently analysed for substance P and neurokinin A by radioimmunoassay. There were significantly increased levels of substance P-like immunoreactivity (SP-LI) and neurokinin A-like immunoreactivity (NKA-LI) in gingivitis and periodontitis sites compared with healthy sites. Both tachykinins were significantly elevated in periodontitis affected subjects, with significantly more tachykinin-like immunoreactivity at healthy sites in periodontitis affected compared with periodontally-healthy subjects. Despite the considerable individual variation in the levels of SP-LI and NKA-LI, both tachykinins were present at levels at which they could have biological activity. It is concluded that substance P and neurokinin A may have a rôle in the pathogenesis of periodontal disease and that further investigations could prove useful in clarifying the mechanisms through which neuropeptides could modulate periodontal health and disease.

Evaluation of major parotid glycoproteins in patients with burning mouth syndrome

OBJECTIVE

This study was to investigate the potential role of salivary glycoproteins in burning mouth syndrome.

STUDY DESIGN

This study compared major parotid glycoproteins in a group of patients with burning mouth syndrome and age-, sex-, race-matched healthy controls.

RESULTS

By use of a glycoprotein detection kit, saliva from both patients and controls exhibited three major parotid glycoprotein banding patterns consisting of either one or two bands, molecular weights 58 kDa and 77 kDa. The strong lectin reactivity of major parotid glycoproteins with Ricinus communis agglutinin suggests that galactose is the most prevalent terminal sugar. In addition, major parotid glycoproteins were shown to express blood group antigen H. On the basis of metachromatic characteristics and immunologic reactivity, major parotid glycoproteins appear to be members of the proline rich protein multigene family, proline rich glycoprotein, genetic polymorphism G1. No qualitative difference was observed in major parotid glycoprotein banding patterns between patients and controls.

CONCLUSION

These findings do not support a role for major parotid glycoproteins in burning mouth syndrome.

Cross-reactivity of antibodies raised to Pseudomonas fluorescens protease with extracellular proteins produced by meat-spoiling pseudomonads

The cross-reactivity patterns of antibodies to Pseudomonas fluorescens protease with the extracellular proteins produced by a number of meat-spoiling pseudomonads were studied. Immunoblotting studies showed that purified IgG to Ps. fluorescens protease cross-reacted with extracellular proteins in the cell culture supernatant fluids of Pseudomonas spp., including Ps. fragi and Ps. lundensis. In the case of Ps. lundensis and Pseudomonas spp. 11390, the cross-reactive moieties were of similar molecular weight to the Ps. fluorescens protease (46 kDa). However, in Ps. fragi the cross-reactive moiety was a lower molecular weight protein (8 kDa). This may represent a fragment of the active enzyme. These results indicate the presence of common antigenic determinants among the proteases of meat spoiling pseudomonads.

Alcohol intake in patients admitted acutely to a general medical unit

The role of alcohol in causing acute medical admissions is recognised but not well quantified. Using a questionnaire we have studied prospectively alcohol intake in patients aged 18-60 years admitted to a medical unit and have analysed the contribution of alcohol to their admission. One hundred and six patients (61 male: 45 female) who fulfilled our preset age criteria were studied. Alcohol intake (mean +/- SEM) was 9 +/- 1 and 12 +/- 1 units on average and heavy drinking days respectively, and 38 +/- 6 units during their last drinking week. Gamma glutamyl transferase (GGT) was > 60 U/l (upper limit of normal) in 29 (n = 92). Eighteen (30%) men had drunk > 50 units and seven (16%) women had taken > 35 units in their last drinking week. In 25 (41%) men and 11 (24%) women alcohol intake was felt to contribute to their admission. In this subgroup, intake was 15 +/- 2 and 20 +/- 1 units on average and heavy drinking days respectively, and 87 +/- 13 units in the last drinking week. GGT was available in 29 and was abnormal in 18. Admission diagnoses were drug overdose (n = 16), alcohol withdrawal symptoms (n = 7), liver disease (n = 6), haematemesis (n = 14) and others (n = 3). Fifteen (42%) felt they had a definite alcohol problem. The use and abuse of alcohol contributes significantly to the general medical workload in the age group studied.

The recovery of proteolytic activity using the Salivette system

The recovery of proteolytic activity from human saliva was investigated using the Salivette system. Comparison of activity measurements with those obtained from whole saliva indicated that the Salivette system allowed increased recovery of proteolytic activity suggesting minimal enzyme binding to the cotton roll. The significance of these results is that previous estimates of proteolytic activity in mixed saliva may not have been due to increasing release of proteases by stimulation of secretion, but by altered binding properties of the sampling system used.

A new method for the detection of proteolytic activity in Pseudomonas lundensis after sodium dodecyl sulfate-polyacrylamide gel electrophoresis

A new method for the visualization of proteolytic activity in cell culture supernatant from Pseudomonas lundensis after sodium dodecyl sulfate (SDS)--gel electrophoresis is described. Following conventional electrophoresis, the gel is washed in a methanol-containing buffer to facilitate partial removal of SDS. After incubation with 0.5% casein the gel is stained for protein with Coomassie Brilliant Blue R-250. Bands with proteolytic activity appear as clear areas in the gel against a blue-stained background. Molecular weight standards electrophoresed in the same gel stain more intensely than the background and allow determination of the molecular weights of the proteolytic components. The sensitivity of post-electrophoretic reactivation in SDS-gels was determined using trypsin as standard. A slight modification of the technique allowed detection of proteolytic activity in nondenaturing and in isoelectric focusing gels.

The determination of asialoglycoforms of serum glycoproteins by lectin blotting with Ricinus communis agglutinin

Serum proteins were fractionated by polyacrylamide gel electrophoresis under denaturing conditions and transferred to nitrocellulose membranes. The blotted polypeptides were probed with biotinylated Ricinus communis lectin (RCA120) followed by streptavidin/alkaline phosphatase. This procedure detected five asialoglycoproteins (alpha 2-macroglobulin, transferrin, alpha 1-antitrypsin, alpha 1-antichymotrypsin and haptoglobin beta chain). The asialoform of the alpha 1-trypsin inhibitor was found to be decreased in inflammation.