Cross-Resistance between AZT, ddl and other Antiretroviral Drugs in Primary Isolates of HIV-1

Primary isolates of human immunodeficiency virus type 1 (HIV-1) were tested for sensitivity to 3′-azido-3′-deoxythymidine (AZT), 3′-fluoro-3′-deoxythymidine (FLT), 2′,3′-dideoxyinosine (ddl), 2′,3′-dideoxycytidine (ddC), and phosphonoformate (PFA) in peripheral blood mononuclear cells (PBMC). Forty-eight isolates from HIV-1-infected patients treated with AZT for various lengths of time were investigated. More than half of the patients harboured virus resistant to AZT after treatment. There was no correlation between resistance and length of therapy. A significant correlation between resistance to AZT and reduced susceptibility to ddl and ddC was apparent. These results indicate that development of resistance to AZT is common in patients treated with AZT and may be associated with reduced sensitivity to ddl and ddC.

Inhibition by azidothymidine triphosphate of reverse transcriptase from paired AZT-susceptible and -resistant primary isolates of human immunodeficiency virus type 1

The kinetics and inhibition by 3′-azido-3′-deoxythymidine triphosphate (AZT-TP) of reverse transcriptase (RT) from paired AZT-susceptible and -resistant primary isolates of HIV-1 taken from patients before and after therapy were examined in vitro. The resistant isolates showed mutations in the RT at positions 67, 70, 215 and 219, and also in one case at positions 41 and 215. No changes in the Vmax, the Km for dTTP or the Ki for AZT-TP of a magnitude sufficient to account for the observed development of resistance to AZT in primary isolates from these patients were found.

Synergistic Inhibition of Primary Isolates of Human Immunodeficiency Virus Type 1 by Combinations of 3′-Fluoro-3′-Deoxythymidine and 2′,3′-Dideoxyinosine

We examined the antiviral effect against human immunodeficiency virus type 1 of 3′-fluoro-3′-deoxythymidine and 2′,3′-dideoxyinosine, both alone and in combination. Primary isolates of human immunodeficiency virus were used directly after isolation on peripheral blood mononuclear cells, without culturing on established cell lines, in order to maintain close similarity to the clinical situation. All isolates were synergistically inhibited by combinations of the drugs, though their susceptibility to the separate drugs varied. The selectivity indices of the combinations were similar to that of the individual drugs. The synergistic combination of 3′-fluoro-3′-deoxythymidine and 2′,3′-dideoxyinosine appears promising for the treatment of human immunodeficiency virus infection and deserves further investigation.

Community survey of rabies knowledge and exposure to bats in homes - Sumter County, South Carolina, USA

Subsequent to a human rabies death in Sumter County, South Carolina, we assessed the frequency of exposures to bats in homes and citizens' rabies knowledge. A self-administered survey was mailed to 6033 randomly selected Sumter County addresses. The survey inquired about household exposures to bats and respondents' rabies knowledge. Surveys were returned by mail for descriptive analysis. Of 597 respondents, 3.5% (21/597) reported having bats living in (2.8% or 17/597) or entering their homes (2.5% or 15/597) during 2010-2012. Respondents generally understood that mammals transmit rabies virus through bites, but were less aware of the severity of rabies illness and modern post-exposure vaccine administration. Respondents were unsure about how to exclude bats from homes and ranked highly both healthcare and non-healthcare entities as preferred resources for obtaining assistance with bat-related concerns. We found potential for human exposures to bats in Sumter County households and gaps in citizen knowledge of rabies and bat exclusion. Public health officials should engage non-healthcare partners in assistance disseminating rabies educational materials and for providing appropriate referral for persons potentially exposed to bats.

Secretory leukocyte protease inhibitor and its potential interactions with elastase and cathepsin B in gingival crevicular fluid and saliva from patients with chronic periodontitis

BACKGROUND AND OBJECTIVE

Elastase is carried into the oral cavity by gingival crevicular fluid (GCF) from periodontal lesions. Our study investigated the regulation of elastase activity by secretory leukocyte protease inhibitor (SLPI) and the possible action of another GCF protease on this protective salivary component.

MATERIAL AND METHODS

Whole-mouth saliva (WMS), parotid saliva (PS) and GCF were obtained from 19 patients with periodontitis. The concentrations of active elastase and cathepsin B were determined using peptide substrates. SLPI and alpha1-proteinase inhibitor (alpha1PI) concentrations were determined using enzyme-linked immunosorbent assays (ELISAs). The molecular forms of SLPI were examined by immunoblotting.

RESULTS

The molar concentrations of elastase, cathepsin B and alpha1PI were higher in GCF than in WMS and especially PS (p < 0.0002). The GCF SLPI concentrations were also higher than the WMS SLPI concentrations (p < 0.05). All WMS components increased with GCF content, significantly for elastase and SLPI (p < 0.002). In GCF, the concentration of alpha1PI was higher than the concentration of SLPI (p < 0.0002), while there was no significant difference for WMS. SLPI and elastase levels in GCF and WMS were inversely related (p < 0.005). In SLPI immunoblots, PS contained only the intact 14-kDa molecule of SLPI, while WMS also contained an 8-kDa fragment. For WMS there was a positive correlation between SLPI degradation and cathepsin B (p < 0.002). Incubation of WMS alone or of PS with GCF in the presence of cysteine proteinase activators caused SLPI immunoreactivity to shift to 8 kDa.

CONCLUSION

For GCF, serum-derived alpha1PI is the major elastase inhibitor, but in WMS SLPI probably reduces activity. The inflamed gingivae can be an additional source of SLPI in the oral cavity, but here the molecule is apparently cleaved by GCF cysteine proteinases, such as cathepsin B.

Effects of autonomic agonists and immunomodulatory cytokines on polymeric immunoglobulin receptor expression by cultured rat and human salivary and colonic cell lines

OBJECTIVE

Immunoglobulin A (IgA) is transported across glandular epithelial cells by polymeric immunoglobulin receptor (plgR), with each receptor molecule participating in only one round of transcytosis. Nerve-related stimuli rapidly increase salivary secretion of IgA, while concentrations are increased in the autoimmune disease Sjögren's syndrome. Our aim here was to determine whether autonomic agonists and cytokines present in Sjögren's-affected glands can up-regulate salivary cell plgR expression.

METHODS

Cultures of rat parotid acinar cells (PAR C5) and human submandibular gland ductal cells (HSG) were exposed to carbachol or adrenaline for 24 h and to interleukin-4 and/or interferon-gamma for 48 h. The human colonic cell line HT-29 served as a positive control for cytokine response. plgR mRNA was quantified by reverse transcription and real-time PCR and protein expression was examined by immunoblotting.

RESULTS

Carbachol increased plgR mRNA levels significantly in all cells but adrenaline did so only with PAR cells (P<0.05). HSG and HT-29 cells both up-regulated plgR gene transcription on exposure to interleukin-4 and interferon-gamma either alone or in combination (P<0.05). By contrast, production of plgR mRNA in PAR cells tended to decrease in response to all cytokine treatments. plgR protein levels rose in line with mRNA expression in cytokine-treated HT-29 cultures (P<0.05).

CONCLUSIONS

Autonomimetics can up-regulate plgR transcription in transformed and neoplastic salivary and colonic cells, although intracellular coupling mechanisms require further investigation. Immunomodulatory cytokines increased plgR expression in one of the salivary cell lines, but additional work is needed to establish whether this occurs in Sjögren's patients.

Collagen degradation by interleukin-1beta-stimulated gingival fibroblasts is accompanied by release and activation of multiple matrix metalloproteinases and cysteine proteinases

OBJECTIVE

Several collagenolytic matrix metalloproteinases (MMPs) have recently been identified in gingival fibroblasts, while secreted cysteine proteinases could also participate in connective tissue destruction in periodontitis. To clarify their involvement, we examined enzyme release during collagen breakdown by cultured cytokine-stimulated fibroblasts.

MATERIALS AND METHODS

Gingival fibroblasts were derived from four chronic periodontitis patients and cultured on collagen gels in serum-free medium for 1-4 days. Collagenolysis was measured by hydroxyproline release into the medium. Proteinases were assessed by electrophoresis and immunoblotting.

RESULTS

Adding interleukin-1beta resulted in progressive gel breakdown. This was associated particularly with a shift in MMP-1 band position from proenzyme to active enzyme and the appearance of active as well as proenzyme forms of cathepsin B. There was also partial processing of pro-MMP-13 and increased immunoreactivity for active cathepsin L. In addition, both pro-forms and active forms of MMP-8, membrane-type-1-MMP and MMP-2 were present in control and treated cultures.

CONCLUSIONS

Fibroblast MMP-1 was most likely responsible for collagen dissolution in the culture model, while cathepsin B may have been part of an activation pathway. All studied proteinases contribute to extracellular matrix destruction in inflamed gingival tissue, where they probably activate each other in proteolytic cascades.

Collagenase-2 (MMP-8) and collagenase-3 (MMP-13) in adult periodontitis: molecular forms and levels in gingival crevicular fluid and immunolocalisation in gingival tissue

AIM

To determine the cellular and molecular forms of MMP-8 (collagenase-2) and MMP-13 (collagenase-3) associated with chronic adult periodontitis by examining the species present in gingival crevicular fluid (GCF) and enzyme distribution in gingival tissue.

METHODS

30-s GCF samples were collected directly from the periodontal pockets of 12 untreated patients using filter paper strips. After elution into buffer, the samples were examined by Western immunoblotting with polyclonal antibodies for MMP-8 and MMP-13 and quantification by scanning image analysis. Individual band intensities were expressed as a percentage of total sample absorbance and mean patient values were calculated. Gingival tissue from 6 patients was fixed in formalin and embedded in paraffin wax. MMP-8 and MMP-13 were localised using the same antibodies and an avidin-biotin-peroxidase detecting system. Double staining was performed with a contrasting substrate reaction.

RESULTS

The majority of MMP-8 staining in pre-treatment GCF was present in 80, 75 and 60 kD bands corresponding to prepro-, pro- and active forms of PMN-type enzyme. 43 and 38 kD bands evidently represented active, fibroblast-type MMP-8. Immunoreactivities at >100 kD and < or =30 kD were probably enzyme-inhibitor complex and degraded fragments, respectively. MMP-13 was seen mainly as 60 kD proenzyme with some 40 kD active enzyme and a small proportion of >100 kD complex. The percentages of MMP-8 PMN-type enzyme and MMP-13 proenzyme bands correlated significantly with gingival and bleeding indices (p<0.05). Immunohistochemistry demonstrated MMP-8 in PMNs, sulcular epithelial and also plasma cells in inflamed gingival connective tissue. MMP-13 immunoreactivity was detected in the sulcular epithelium and in macrophage-like cells.

CONCLUSION

Multiple species and elevated levels of both MMP-8 and MMP-13 from many rather than single cellular sources in the diseased periodontium are identified in untreated periodontitis GCF and active forms contribute to GCF collagenase activity.

Matrix metalloproteinase-8 levels and elastase activities in gingival crevicular fluid from chronic adult periodontitis patients

AIM

To make an initial assessment of the periodontal diagnostic potential of immunoreactive matrix metalloproteinase-8 (MMP-8) in gingival crevicular fluid (GCF) by comparison with elastase activity which has previously been associated with disease severity and progression.

METHODS

GCF was collected from molar and premolar sites of 16 chronic adult periodontitis patients before treatment and 13 of this group 2 weeks after scaling and root planing. Samples were analysed for MMP-8 by immunofluorometric assay and for elastase activity with a fluorogenic substrate.

RESULTS

Mean patient clinical parameters and GCF enzyme totals both decreased significantly after treatment. Total MMP-8 levels and elastase activities generally correlated significantly with gingival and bleeding indices. For GCF concentrations, only MMP-8 showed a significant fall after treatment, and some significant correlations with clinical parameters. Amounts of the 2 enzymes correlated significantly with each other.

CONCLUSIONS

Similarities between MMP-8 and elastase probably reflect the fact that both enzymes are associated mainly with neutrophils: MMP-8 levels may have fallen more after treatment because the assay, unlike that for elastase, would most likely not have detected much enzyme bound to alpha-macroglobulin. The immunoassay for MMP-8 is more specific and convenient than functional collagenase assays, and might be suitable for monitoring the periodontal condition.

Differences in bcl-2- and bax-independent function in regulating apoptosis in sensory neuron populations

Bcl-2 and Bax are cytoplasmic proteins that have antagonistic actions on apoptosis. To investigate the extent to which these proteins function independently in regulating neuronal apoptosis, we studied the in vivo and in vitro development of two populations of sensory neurons of mouse embryos that lack one or both proteins. Absence of Bcl-2 increased neuronal apoptosis and reduced the number of neurons in both the trigeminal and nodose ganglia during the period of naturally occurring neuronal death. Absence of Bax reduced neuronal apoptosis and increased the number of surviving neurons in these ganglia and promoted sustained neuronal survival in neurotrophin-free cultures. In contrast, the elimination of both Bcl-2 and Bax had different consequences for these populations of neurons. In nodose ganglia, apoptosis was suppressed just as effectively in embryos lacking both proteins as in embryos lacking Bax alone, and neurons that lacked both proteins survived just as effectively in neurotrophin-free medium as Bax-deficient neurons. This suggests that for nodose neurons, the suppression of apoptosis by Bcl-2 is entirely dependent on the presence of Bax. In trigeminal ganglia, although neuronal apoptosis was reduced in embryos lacking both proteins compared with wild-type embryos, there were significantly more apoptotic neurons and significantly fewer surviving neurons in embryos lacking both proteins compared with Bax-deficient embryos, and significantly fewer trigeminal neurons from embryos lacking both proteins survived in neurotrophin-free medium compared with trigeminal neurons that lacked Bax alone. This suggests that for trigeminal neurons, Bcl-2 functions partly independently of Bax in regulating survival. Our results therefore suggest that the relative independence of Bcl-2 and Bax in regulating neuronal survival differs from one population of neurons to another.

Advances in periodontal diagnosis. 10. Potential markers of bone resorption

This paper describes the markers of bone resorption which might serve as potential markers for periodontal disease activity. It firstly describes the bone specific proteins which are involved in bone mineralisation and the role they play in this process. It then explains how they may pass into GCF and reviews those studies which have attempted to relate these factors to periodontal disease severity and activity. It next discusses the difficulties in isolating and detecting these factors in GCF and their possible use as markers for periodontal disease activity. As the final part in the series it lastly discusses the possible uses of predictive diagnostic tests of periodontal disease activity in dental practice.

Advances in periodontal diagnosis. 9. Potential markers of cell death and tissue degradation

This paper describes the potential markers of cell death and connective tissue degradation which might serve as markers of periodontal disease activity. The first section deals with enzymes released by dead and degenerating cells. Firstly, it describes how these pass from the periodontal tissues into gingival crevicular fluid (GCF) and explains that these enzymes have been used as markers of cell death in medicine for several decades. It then discusses the main enzymes in this group, aspartate amino transferase (AST) and lactate dehydrogenase (LDH) and reviews those studies which have attempted to relate these enzymes to periodontal disease severity and activity. Secondly, it describes the potential markers of connective tissue degradation, fibronectin, hydroxyproline-containing peptides and glycosaminoglycans (GAGs) and explains how these are produced. Finally, it describes the only commercial test kit for markers in this group (GCF-AST).

Advances in periodontal diagnosis. 8. Commercial diagnostic kits based on GCF proteolytic and hydrolytic enzyme levels

Biomarkers of periodontal disease activity may be obtained from potential proteolytic and hydrolytic enzymes of inflammatory cell origin. Commercial diagnostic tests and those under development are discussed along with their advantages and disadvantages.

Advances in periodontal diagnosis. 7. Proteolytic and hydrolytic enzymes link with periodontitis

Biomarkers of periodontal disease activity may be obtained from potential proteolytic and hydrolytic enzymes of inflammatory cell origin. Studies that have sought to correlate these enzymes with periodontal disease activity are reviewed with special consideration given to collagenases, cysteine, aspartate and serine proteinases, beta-glucuronidase, arylsulphate, alkaline and acid phosphatases, myeloperoxidase, lysozyme and lactoferrin.

Advances in periodontal diagnosis. 6. Proteolytic and hydrolytic enzymes of inflammatory cell origin

Potential proteolytic and hydrolytic enzymes of inflammatory cell origin might serve as biomarkers of periodontal disease activity. The role of these enzymes in periodontal pathology, particularly in respect of collagen and proteoglycan degradation, is discussed. The cellular location of these enzymes and their normal control mechanisms by endogenous inhibitors is described.

Advances in periodontal diagnosis. 5. Potential inflammatory and immune markers

The potential inflammatory and immune markers that might detect periodontal disease severity or activity are examined. The role of inflammatory and immune factors passing from the tissues into the gingival crevicular fluid (GCF) are considered. GCF sampling is a necessary part of all diagnostic tests based on gingival and periodontal tissue factors. Inflammatory and immune factors found in GCF are reviewed with special reference to the humoral immune response, complement, cytokines and prostaglandins. The possible development of diagnostic tests based on these factors are discussed.

Advances in periodontal diagnosis. 4. Potential microbiological markers

The potential of bacterial markers for the detection of periodontal disease activity is discussed. Chronic periodontitis has been associated with subgingival bacteria. Techniques are available to detect and distinguish different bacteria. In subgingival plaque, bacterial proteases can be detected. Commercial diagnostic tests based on bacterial factors are described.

Advances in periodontal diagnosis. 3. Assessing potential biomarkers of periodontal disease activity

The methods for assessing potential biomarkers of periodontal disease activity are considered. This is necessary because a detailed examination of all the relevant research evidence is an essential process in assessing the possible clinical usefulness of a periodontal diagnostic test system based on any one of these markers.

Advances in periodontal diagnosis. 2. New clinical methods of diagnosis

This paper describes the new methods of periodontal diagnosis. An outline of the problems of periodontal probing techniques is followed by a discussion of the advances made by the use of constant pressure electronic probes. We finally highlight the problems of periodontal radiographical techniques, leading on to a description of computer-aided radiographic methods--in particular, digital subtraction radiology and computer-assisted linear radiology.

Advances in periodontal diagnosis. 1. Traditional clinical methods of diagnosis

This series will consider the limitations of traditional periodontal diagnostic techniques and the recent advances which have sought to overcome them. It will cover improvements in probing and radiographic techniques and also discusses the attempts to find bacterial or tissue-derived markers which will diagnose or predict periodontal disease activity. The first paper describes the traditional methods of periodontal diagnosis.

Cathepsin B, alpha2-macroglobulin and cystatin levels in gingival crevicular fluid from chronic periodontitis patients

Gingival crevicular fluid (GCF) was collected from 16 molar and premolar sites in each of 20 chronic periodontitis patients before and after periodontal therapy using filter paper strips. These were eluted individually into buffer for determination of cathepsin B and its endogenous inhibitors, alpha2-macroglobulin and cystatin. Cathepsin B activity was assayed with a fluorogenic peptide substrate, alpha2-macroglobulin by enzyme-linked immunosorbent assay and cystatin activity by inhibition of papain. Total amounts of enzyme and inhibitor per GCF sample decreased after treatment and correlated positively with pocket depth and gingival, bleeding and plaque indices. These comparisons were nearly always statistically significant for pooled site data and sometimes so for mean patient values. The amounts of alpha2-macroglobulin and cystatin were greater than those of cathepsin B and, surprisingly, enzyme and inhibitor levels correlated positively with each other. Experiments with purified reagents, however, demonstrated that the cathepsin B: alpha2-macroglobulin complex was still active against the low molecular weight substrate and that cystatin levels in GCF are probably insufficient to inhibit the enzyme substantially These factors may explain why GCF cathepsin B activity reflects the clinical status of periodontal lesions and has been identified in another study as a promising indicator of disease progression.

Ultrastructural localization of cathepsin B in gingival tissue from chronic periodontitis patients

Loss of tooth support during chronic periodontitis is very likely to involve tissue proteases such as cathepsin B. The distribution of this enzyme was, therefore, examined in ultrathin sections of gingival tissue embedded in acrylic resin and labelled with a sheep polyclonal antibody and gold-conjugated secondary antibody. Macrophages and fibroblasts in both inflamed and non-inflamed areas of tissue showed labelling, and this was strongest in lysosomes, corresponding to the normal intracellular location of cathepsin B. However, additional gold particles were found on the surface of these cells. Monocytes in inflamed areas also had surface labelling, some of which was present on microvilli. Labelled collagen fibres adjacent to all three cell types indicated that cathepsin B had been released into the immediate extracellular environment. Plasma membrane cathepsin B has previously been associated with cancers, but enzyme redistribution and release in the gingiva may have been linked to the inflammatory response, since fibroblasts and macrophages in non-inflamed areas showed less labelling of their surface and adjacent collagen. The collagen labelling added to evidence that cathepsin B can function extracellularly as well as intracellularly in connective tissue degradation. This destructive role for the enzyme is supported by our earlier measurements of increased biochemical activity in chronic periodontitis.

Outcome after incision and drainage with fistulotomy for ischiorectal abscess

Concomitant anal fistulotomy (F) and incision and drainage (I&D) of ischiorectal abscesses (IA) are often avoided, for fear of irreversibly impairing anal continence. However, failure to identify and treat the frequently associated trans-sphincteric anal fistula dooms the patient to recurrent anal suppurative disease. We have employed an aggressive approach of performing I&D and F for IA at the time of initial presentation. Adequate drainage is assured by placement of counterincisions and Penrose drains to minimize the time for healing of the perianal wound. Drainage is followed by a careful examination of the anal canal for fistula localization followed by fistulotomy, or less frequently by cutting seton placement. We present our experience with this approach to IA, with special attention paid to the evaluation of recurrence rates and anal continence. This paper represents a retrospective review of 80 patients with IA managed from 1983 to 1996. Operative records and office records were reviewed, and follow-up data were obtained by telephone interview. Internal fistulous openings were identified in 55 (68.8%) patients. Surgeries included: 38 (47.5%) I&D and F, 8 (10%) I&D and seton, and 34 (42.5%) I&D alone. Follow-up data were available on 99 per cent of patients; mean, 44.3 months. Results showed a 44 per cent recurrence rate in those who underwent I&D as compared with 21.1 per cent following I&D and F. 11.8 per cent of patients treated with I&D experienced a change in their level of continence postoperatively as compared to 15.8 per cent treated with I&D and F. The results indicate that an aggressive approach to IA allows identification of a trans-sphincteric fistula in 57.5 per cent of patients with IA. Therefore, optimal surgical management for IA appears to be I&D and F, resulting in a lower recurrence rate and comparable morbidity as compared to I&D alone.

Characterization of protease activities in Capnocytophaga spp., Porphyromonas gingivalis, Prevotella spp., Treponema denticola and Actinobacillus actinomycetemcomitans

Protease activities in cell sonicates of defined bacterial strains were examined using peptide substrates and class-specific inhibitors. Capnocytophaga spp. all produced serine dipeptidyl peptidase activity and arginine/lysine, elastase- and chymotrypsin-like enzymes with some metalloprotease characteristics. The elastase-like activity was strongest in Capnocytophaga sputigena, but the others were greatest in Capnocytophaga gingivalis. The latter also had a separate arginine-specific enzyme which appeared not to be present in the other two species. Porphyromonas gingivalis showed serine dipeptidyl peptidase activity and very strong arginine and lysine cysteine protease activities. Prevotella spp. had inhibitor-resistant dipeptidyl peptidase activity and arginine cysteine protease activity that was much weaker but biochemically similar to P. gingivalis. Treponema denticola possessed a strong trypsin-like serine protease activity as well as very weak dipeptidyl peptidase and chymotrypsin-like activities that were sensitive to some cysteine protease reagents. Actinobacillus actinomycetemcomitans showed a novel alanine- and lysine-specific activity, but its nature was unclear.

Investigations into the cellular contribution to host tissue proteases and inhibitors in gingival crevicular fluid

Gingival crevicular fluid (GCF) was collected from chronic periodontitis patients using plastic micropipettes and coverslip smears stained with antibodies for leukocyte markers and Toluidine Blue for mast cells. The smears consisted of 70-80% granulocytes, 10-20% monocytes/macrophages, 5% mast cells and 5% T lymphocytes; no B lymphocytes were found. Proteases and inhibitors in GCF cells were investigated by enzyme cytochemistry using 2-methoxy-4-naphthylamine-linked peptide substrates and simultaneous coupling to Fast Blue B and immunocytochemistry using biotinylated secondary antibodies and an alkaline phosphatase/new fuchsin detecting system. Elastase was detected in granulocytes, cathepsin B in macrophages, dipeptidyl peptidases II and IV in a small proportion of macrophages, dipeptidyl peptidase IV in a few T lymphocytes, tryptase in mast cells and alpha-1-proteinase inhibitor and alpha-2-macroglobulin in some macrophages. GCF was also collected on filter paper strips and eluted into buffer for biochemical enzyme assays. Lysis of cells by addition of detergent to the elution buffer increased activities to 140-240% of control values. Removal of cells by centrifugation reduced measured activities to 1-30% of original figures; this effect was less if samples were pre-treated with detergent. Proteases from inflammatory cells therefore appear to make up most of the measured enzyme activity in GCF, and this association may explain recent correlations with periodontal disease progression.

Histochemical and immunocytochemical localization of dipeptidyl peptidases II and IV in human gingiva

Dipeptidyl peptidase (DPP) II and IV activities were demonstrated in unfixed cryostat sections of gingival tissue from chronic periodontitis patients using histochemistry with 2-methoxy-4-naphthylamine (MNA) substrates. In the case of DPP IV, enzyme localization was confirmed by immunocytochemistry with mouse monoclonal antihuman DPP IV (CD26) antibody. Inflammatory cells containing enzyme were identified in adjacent sections with mouse monoclonal antibodies directed against leukocyte differentiation antigens. Lys-Ala-MNA and Ala-Pro-MNA staining in acid buffer for DPP II was only found in a few fibroblasts in superficial tissue. Staining with Gly-Pro-MNA and Ala-Pro-MNA in alkaline buffer for DPP IV was localized in some CD4 and CD8 positive T lymphocytes, CD68 positive macrophages, and fibroblasts and these cells also reacted with the enzyme antibody. DPP IV-containing macrophages and T lymphocytes were seen in the epithelium. In deeper granulomatous tissue Gram positive and negative bacteria stained with the histochemical substrates, but not the DPP IV antibody. Fibroblast DPP II and IV might participate in cellular interactions with collagen, while T lymphocyte DPP IV may be involved in cell signalling.

The relationship between gingival crevicular fluid cathepsin B activity and periodontal attachment loss in chronic periodontitis patients: a 2-year longitudinal study

This study aims to determine whether gingival crevicular fluid (GCF) cathepsin B levels, total activity (TA) and concentration (EC) predict progressive attachment loss (AL). Seventy-five previously untreated patients with moderate periodontitis were recruited. GCF was collected from 16 molar and premolar mesiobuccal sites and probing attachment level (PAL) and probing depth (PPD) were measured with an electronic probe. Gingival, gingival bleeding and plaque indices were then scored. Prior to baseline patients were given basic periodontal treatment after which the above procedures were repeated. Carefully localized radiographs were taken of the test teeth and repeated annually. Patients were seen 3-monthly for 2 yr and the procedures were repeated. One hundred and twenty-one AL sites, 90 rapid AL (RAL) and 31 gradual AL (GAL), in 49 patients were detected. Cathepsin B levels (TA & EC) at RAL sites were significantly higher (p < 0.0001) than paired control sites at the attachment loss time (ALT) and prediction time (PT). Mean levels (TA & EC) over the study period at GAL sites were significantly higher (p < 0.0001) than paired control sites. Using a critical value (CV) of 7.5 microU/30 s (TA) and 30 microU/microL (EC) showed a sensitivity of 100% and specificity of 99.83% (TA) and 100% and 99.75%(EC) at both ALT & PT. Mean cathepsin B levels (TA & EC) were significantly higher (p < 0.0001) at RAL and GAL sites than non-attachment loss (NAL) sites in AL patients in intrapatient comparisons and mean patient levels were significantly higher (p < 0.0001) in AL patients than NAL patients in interpatient comparisons. These results indicate that GCF cathepsin B may serve as a predictor of attachment loss.

Correlation between gingivain/gingipain and bacterial dipeptidyl peptidase activity in gingival crevicular fluid and periodontal attachment loss in chronic periodontitis patients. A 2-year longitudinal study

The aim of this study is to determine whether either gingival crevicular fluid (GCF) bacterial gingivain/gingipain or dipeptidyl peptidase (DPP) levels, total activity (TA) and concentration (EC), predict progressive attachment loss (AL) in 75 patients with moderate periodontitis. GCF was collected from 16 molar and premolar mesiobuccal sites and then clinical attachment level (CAL) and probing depth (PD) were measured with an electronic constant pressure probe. Lastly, gingival, gingival bleeding, and plaque indices were scored. Prior to the baseline visit, patients were given basic periodontal treatment after which the above procedures were repeated. In addition, carefully localized radiographs were taken of the test teeth and repeated annually. Patients were then seen every 3 months for 2 years and the clinical measurements repeated at each visit. In 48 patients, 124 AL sites, 91 rapid AL (RAL), and 33 gradual AL (GAL) were detected. Gingivain/gingipain and bacterial DPP levels (TA and EC) at RAL sites were significantly higher (P < or = 0.0001) than at paired control sites at the attachment loss time (ALT) and prediction time (PT). Mean levels over the study period of both proteases (TA and EC) at GAL sites were significantly higher (P < or = 0.0001) than those at paired control sites. The GCF levels of gingivain/gingipain were always higher than those of DPP. Critical values (CV) of 5 microU/30 seconds (TA) and 30 microU/microL (EC) for both proteases showed high sensitivity and specificity values for TA and EC, which were the same at both ALT and PT. The positive predictive values were higher for gingivain/ gingipain. Mean site levels, over the course of the study, of both proteases (TA and EC) were significantly higher (P < or = 0.0001) at AL, RAL, and GAL sites than non-attachment loss (NAL) sites in AL patients and mean patient levels were significantly higher (P < or = 0.0001) in AL, RAL, and GAL patients than NAL patients. These results indicate that both of these bacterial proteases in GCF may be predictors of periodontal attachment loss.

A 2-year longitudinal study of elastase in human gingival crevicular fluid and periodontal attachment loss

The purpose of this study is to determine whether gingival crevicular fluid (GCF) elastase total activity (TA) and concentration (EC) correlate with and predict progressive attachment loss (AL). 75 previously untreated patients with moderate periodontitis were recruited. GCF was collected from 16 molar and premolar mesiobuccal sites and probing attachment loss (PAL), probing depth (PPD), gingival index (GI), gingival bleeding index (GBI) and plaque index (Pl.I) were measured. PAL and PPD were measured with an electronic, constant pressure probe. Patients were given basic periodontal treatment prior to baseline when the above procedures were repeated. In addition, carefully localised radiographs were taken of the test teeth and repeated annually. Patients were seen at 3 months intervals to 2 years and the procedures were repeated. 119 AL sites were detected and 89 of these were rapid AL sites (RAL) and 30 were gradual AL sites (GAL). Elastase levels (TA & EC) at RAL sites were significantly higher (p < or = 0.0001) than paired control sites in the same patient at both the attachment loss time (ALT) and the prediction time (PT). The mean levels (TA & EC) over the study period at GAL sites were significantly higher (p < or = 0.0001) than paired control sites in the same patient. Using a critical value (CV) of 125 micronsU/30 s (TA) and 400 micronsU/micronsL (EC) in 2 x 2 contingency tables showed a sensitivity of 100% and specificity of 99.95% (TA) and a sensitivity of 100% and specificity of 99.91% (EC) at the PT with very similar values at the ALT. Patient level comparisons showed that the mean elastase levels (TA & EC) were significantly higher (p < or = 0.0001) at RAL and GAL sites than non-attachment loss (NAL) sites in AL patients and that the mean levels were significantly higher (p < or = 0.0001) in AL patients than NAL patients. All these results indicate that these CVs for GCF elastase activity may serve as a predictors of future attachment loss.

A comparison of cysteine and serine proteinases in human gingival crevicular fluid with tissue, saliva and bacterial enzymes by analytical isoelectric focusing

Gingival crevicular fluid (GCF) contains several different proteinase activities and the study sought to clarify their sources. Gingival tissue and GCF were collected from chronic periodontitis patients. Gel-filtration chromatography of crude tissue extracts yielded cathepsin B and tryptase fractions sensitive to cysteine and serine proteinase inhibitors, respectively. Cell sonicates of suspected periodontal pathogens were prepared from broth cultures of reference strains. Of these, Porphyromonas gingivalis showed much the strongest activity and this had an effector response consistent with the metal-dependent cysteine proteinase described by others. Banding patterns in GCF, tissue and bacterial samples were compared on substrate-impregnated overlay membranes applied to isoelectric focusing gels. On Z-Val-Lys-Lys-Arg-AFC overlays, GCF had bands corresponding to tissue cathepsin B and the enzyme from P. gingivalis, though a contribution from Treponema denticola could not be ruled out. Use of D-Val-Leu-Arg-AFC overlays showed GCF activity similar to tissue tryptase. In GCF there were additional bands that did not correspond to any tissue or bacterial samples and on Z-Ala-Ala-Lys-AFC overlays these closely resembled activity in parotid saliva. The results confirmed that GCF contains tissue cathepsin B and tryptase, while the apparent presence of enzymes from P. gingivalis and possibly T. denticola is consistent with previous reports linking activity to these organisms. The saliva bands demonstrated that contamination of GCF may occur despite rigorous collection procedures.

Correlation between gingival crevicular fluid dipeptidyl peptidase II and IV activity and periodontal attachment loss. A 2-year longitudinal study in chronic periodontitis patients

OBJECTIVE

The aim of this study is to determine whether gingival crevicular fluid (GCF) dipeptidyl peptidase (DPP) II or IV levels, total activity (TA) and concentration (EC), predict progressive attachment loss (AL).

SUBJECTS AND METHODS

Seventy five patients with moderate periodontitis were recruited. GCF was first collected from 16 molar and premolar mesiobuccal sites and then probing attachment level (PAL) and probing pocket depth (PPD) were measured with an electronic probe. Finally, gingival index, gingival bleeding and plaque indices were scored. Patients were given basic periodontal treatment prior to baseline after which the above procedures were repeated. Patients were seen 3 monthly for 2 years and the procedures were repeated. Carefully localised radiographs were taken of the test teeth annually.

RESULTS

One hundred and twenty AL sites, 88 rapid AL (RAL) and 32 gradual AL (GrAL), in 48 patients were detected. DPP II and IV levels (TA and EC) at RAL sites were significantly higher (P < or = 0.0001) than paired control sites at the attachment loss time (ALT) and prediction time (PT). Mean levels over the study period of both proteases (TA and EC) at GrAL sites were significantly higher (P < or = 0.0001) than other paired control sites. The GCF levels of DPP IV were always slightly higher than those of DPP II. Critical values (CV) of 5 microU per 30 s (TA) and 25 microU microL(-1) (EC) for both proteases showed high sensitivity and specificity values for TA and EC and these were the same at both ALT and PT. The positive predictive values were slightly higher for DPP II. Mean site DPP II and IV levels (TA and EC) in intra-patient comparisons were significantly higher (P < or = 0.0001) at RAL and GrAL sites than non-attachment loss (NAL) sites in AL patients and mean patient levels were significantly higher (P < or = 0.0001) in AL patients than NAL patients in inter-patient comparisons.

CONCLUSIONS

These results indicate that both GCF DPP II and IV may be predictors of periodontal attachment loss.

Comparison of host tissue and bacterial dipeptidyl peptidases in human gingival crevicular fluid by analytical isoelectric focusing

Earlier work has shown that gingival crevicular fluid (GCF) contains dipeptidyl peptidase (DPP) activities that resemble those in host tissue. Here, further comparisons were made with enzymes from suspected periodontal pathogens. Gingival tissue and GCF were collected from patients with chronic periodontitis. DPP II and DPP IV fractions with acid and alkaline pH optima, respectively, were separated from crude tissue extracts by gel-filtration chromatography. Bacterial cell sonicates were prepared from broth cultures of reference strains. There was moderate to strong DPP activity with Capnocytophaga spp., Porphyromonas gingivalis and Prevotella spp., very weak activity with Treponema denticola and no detectable activity with Actinobacillus actinomycetemcomitans or Fusobacterium nucleatum. Banding patterns in GCF, tissue and bacterial samples were compared on substrate-impregnated overlay membranes applied to isoelectric focusing gels. In gels washed with acid buffer, GCF had bands corresponding to tissue DPP II. Use of an alkaline washing buffer showed GCF activity which closely matched tissue DPP IV that had been pretreated with neuraminidase, an enzyme found by others in the gingival crevice. P. Gingivalis gave multiple bands and several of these had counterparts in GCF. The apparent presence in GCF of the DPP from P. gingivalis is consistent with the association of this organism with destructive periodontitis.

Bacterial proteases in gingival crevicular fluid before and after periodontal treatment

Our recent work has developed specific assays for bacterial dipeptidyl peptidase (DPP) and trypsin-like proteases and we have found them in gingival crevicular fluid (GCF). The purpose of this study was to determine whether their levels reduce following periodontal treatment of chronic periodontitis patients. The probing depth, probing attachment level, gingival index, gingival bleeding index and plaque index were measured at mesio-buccal sites of molars and premolars in 25 untreated patients. At a second visit GCF was collected on filter paper strips for 30 seconds. GCF volumes were determined with a Periotron and the samples eluted into buffer. The patients than received oral hygiene instruction, supra- and subgingival scaling and other appropriate non-surgical treatment. Four weeks later GCF was collected from the same 16 sites and the clinical parameters were measured again. DPP-like activity was determined fluorometrically with Ala-Pro-AFC at pH 8.0 with and without heating to 60 degrees C for 30 minutes. The heat sensitive portion was taken as bacterial DPP activity. Bacterial trypsin-like protease activity was assayed with Z-Val-Lys-Lys-Arg-AFC at pH 7.0 with 2 mM dithiothreitol and 10 microM Z-Phe-Ala-CH2. Following treatment there were marked reductions in clinical parameters, enzyme total activities and concentrations. All reductions were statistically significant at patient and site level using either individual patient or pooled patient data. Bacterial proteases appear to reflect the clinical status and may be of value in monitoring chronic inflammatory periodontal disease.

Localization of active and inactive elastase, alpha-1-proteinase inhibitor, and alpha-2-macroglobulin in human gingiva

Biochemically, there is usually much less elastase activity in gingival tissue than in crevicular fluid. The tissue distributions of active and inactive elastase and the endogenous inhibitors alpha-1-proteinase inhibitor (alpha 1PI) and alpha-2-macroglobulin (alpha 2M) were therefore compared. Inflamed tissue was obtained from chronic periodontitis patients, and cryostat sections were incubated with the histochemical elastase substrate MeOSuc-Ala-Ala-Pro-Val-MNA. Adjacent sections were examined immunocytochemically with antibodies to neutrophil elastase, alpha 1PI, alpha 2M, and leukocyte differentiation antigens. Antigenic elastase was widely distributed in CD15-positive granulocytes in both the epithelium and lamina propria as well as in granulomatous tissue from infrabony defects. However, there was very limited histochemical staining of these cells, and biochemical activity against the equivalent substrate MeOSuc-Ala-Ala-Pro-Val-AFC could be extracted only from sections with such staining. The pH optimum and effector response of the activity in the extracts were, nevertheless, consistent with those of leukocyte elastase. The large difference between the total elastase content of the tissue, as determined immunocytochemically, and the limited amount of active enzyme, as demonstrated histochemically, indicated that the majority was in an inactive form. The involvement of tissue inhibitors was suggested by the fact that extracts from sections with no histochemical staining reduced biochemical elastase activity in crevicular fluid. alpha 2M was found in many fibroblasts and also some CD68-positive macrophages, which additionally contained alpha 1PI.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of the sensitivities of primary isolates of HIV type 2 and HIV type 1 to antiviral drugs and drug combinations

The sensitivity of primary isolates of HIV-2 to the antiretroviral drugs 3'-azido-3'-deoxythymidine (AZT), 2',3'-dideoxyinosine (ddI), and 3'-fluoro-3'-deoxythymidine (FLT) was measured in vitro in PBMCs and compared to that of primary isolates of HIV-1. HIV-2 isolates showed a similar sensitivity to the drugs compared to HIV-1 isolates. Both the relative and the absolute potencies of the three drugs were similar for inhibition of HIV-1 or HIV-2 replication. The effect of combinations of the antiviral drugs was also studied. The combinations of AZT plus FLT, AZT plus ddI, and FLT plus ddI showed synergistic inhibition of three primary HIV-2 isolates, similar to that previously shown for primary HIV-1 isolates. These results indicate that primary isolates of HIV-2 from untreated persons show a level of sensitivity to antiviral nucleoside analogs similar to that shown by HIV-1 isolates, and are also synergistically inhibited by drug combinations shown to be synergistic against HIV-1. Therapeutic regimes with nucleoside analogs used clinically against HIV-1 infection may therefore also be similarly useful against infection with HIV-2.

Comparative histochemical, biochemical and immunocytochemical studies of cathepsin B in human gingiva

Cathepsin B activity was demonstrated histochemically in unfixed cryostat sections of inflamed human gingiva using the 2-methoxy-4-naphthylamide (MNA) substrates Z-Val-Lys-Lys-Arg-MNA and Z-Ala-Arg-Arg-MNA with a post-azo-coupling technique. Enzyme localisation was confirmed by immunocytochemistry with polyclonal sheep anti-human cathepsin B. In both cases, staining was found in connective tissue fibroblasts and also in cells varying in shape from rounded to more irregular forms. The latter were present both in areas of cellular infiltration and in the oral and pocket epithelium. Examination of adjacent sections with monoclonal antibodies directed against leukocyte differentiation antigens showed that the rounded to irregular cells were CD68 positive macrophages and monocytes. The histochemical staining had the form of fine cytoplasmic particles consistent with the known lysosomal occurrence of cathepsin B. Cells stained by the post-coupling method using the tryptase substrates Z-Ala-Ala-Lys-MNA and D-Val-Leu-Arg-MNA showed a different distribution and morphology, with reaction product confined to mast cell granules. The differences between the cathepsin B and tryptase staining patterns were confirmed by differential extraction from cryostat sections with salt-free and high-salt buffers respectively. Biochemical characterisation of activities in the extracts with the 7-amino-4-trifluoromethyl coumarin (AFC) substrates Z-Val-Lys-Lys-Arg-AFC and Z-Ala-Ala-Lys-AFC and protease inhibitors confirmed the identity of the two enzymes. Selective inhibitors could also be used in histochemical incubations to distinguish between cathepsin B and tryptase staining.

The release, absorption and possible health effects of mercury from dental amalgam: a review of recent findings

Recently many articles have appeared on the subject of mercury from dental amalgam and some of these have questioned its safety as a dental material. This article reviews critically the evidence on mercury release from dental amalgam restorations, its absorption, accumulation and excretion by the body, and its possible relationship to ill-effects. Finally, brief recommendations are given for the handling and usage of dental amalgam.

Comparative histochemical and biochemical studies of mast cell tryptase in human gingiva

Tryptase-like activity has previously been identified biochemically in gingival homogenates and gingival crevicular fluid (GCF) using substrates linked to the 7-amino-4-trifluoromethyl coumarin (AFC) leaving group. In the present study, activity was demonstrated histochemically in tissue sections with analogous 4-methoxy-2-naphthylamide (MNA) substrates. Z-Ala-Ala-Lys-MNA and D-Val-Leu-Arg-MNA were the most sensitive substrates. Comparison of staining patterns with the MNA substrates and toluidine blue indicated that enzyme activity was localized to mast cell secretory granules. Most stained cells were in the lamina propria, but a few were in the epithelium. The number of stained cells was somewhat greater in inflamed tissue from chronic periodontitis patients than in healthy tissue from controls. However, hardly any staining was seen in inflamed granulomatous tissue. Using high-salt buffer containing heparin, it was possible to extract enzyme activity from tissue sections for biochemical analysis with corresponding AFC substrates. Inhibitors gave similar results in the biochemistry and histochemistry. The inhibitor response and pH profile of the enzyme were the same as that found earlier with gingival homogenates and GCF and were again consistent with mast cell tryptase. The enzyme may have a role in the pathology of chronic periodontitis.

The effects of Acacia arabica gum on the in vitro growth and protease activities of periodontopathic bacteria

The antibacterial activity of acacia gum was assessed using fresh isolates and reference strains of Actinobacillus actinomycetemcomitans, Capnocytophaga spp., Porphyromonas gingivalis, Prevotella intermedia and Treponema denticola. A fine aqueous suspension of gum was produced by sonication and then a soluble fraction isolated by centrifugation and membrane filtration. These preparations were incorporated into columbia agar at doubling concentrations. Growth of P. gingivalis and P. intermedia cultures on the agar was inhibited by whole gum sonicate at concentrations of 0.5-1.0% w/v. Both species showed reduced susceptibility when horse blood was present in the agar. The gum soluble fraction did not inhibit growth of any bacterial culture. The effect of acacia on bacterial proteases was examined with cell sonicates from log phase broth cultures. Enzyme activities were determined by fluorimetric assay with various synthetic peptide substrates. Most protease activities reduced in the presence of 0.5% w/v gum sonicate, with the trypsin-like activities of P. gingivalis and P. intermedia proving most sensitive. The gum soluble fraction was nearly always less inhibitory than the sonicate. The action of acacia gum against suspected periodontal pathogens and their enzymes suggests that it may be of clinical value.

Effect of resistance on combination chemotherapy for human immunodeficiency virus infection

The effect of 3 drug combinations (AZT/FLT, AZT/ddI and FLT/ddI) upon the replication of AZT-sensitive and -resistant human immunodeficiency virus (HIV) was studied. The 3 combinations synergistically inhibited drug sensitive virus. However, AZT resistant virus showed an altered response to the combinations containing AZT: synergy was replaced by addition or antagonism. Thus, the susceptibility to a drug may affect the synergistic effect of combinations containing that drug. Other drug combinations may not be affected, since the AZT resistant virus retained a synergistic response to the combination of FLT/ddI. The synergistic effect could be regained upon reversion of resistance; a viral isolate taken after cessation of therapy, which had reverted to sensitivity to AZT, regained the synergistic response to drug combinations containing AZT. These results have implications for the use of combination chemotherapy to treat infection with HIV. Drug combinations will be most useful if the virus is sensitive to all components in the combination. It might be preferable to avoid the inclusion in combinations of drugs to which there is resistance, since we saw an antagonistic effect for combinations containing AZT in AZT resistant virus. Other combinations not containing the drug to which resistance has arisen may maintain their synergistic effect and remain good choices. Thus, a strategy of monitoring drug sensitivity and altering the combination therapy accordingly would appear to offer promise for the treatment of HIV infection.

Loss of synergistic response to combinations containing AZT in AZT-resistant HIV-1

The use of combination chemotherapy for the treatment of HIV-1 infection offers promise for overcoming the problems of toxicity and development of resistance. Primary HIV-1 isolates from three patients before and after treatment with azidothymidine (AZT) were examined for sensitivity to AZT and synergistic response to three different combinations of drugs: AZT+fluorothymidine (FLT), AZT+dideoxyinosine (ddI), and FLT+ddI. All three patients initially harbored AZT-sensitive virus, but posttherapy isolates were resistant to AZT. The pretreatment, AZT-sensitive virus from each patient showed synergistic inhibition by the combinations of AZT+FLT, AZT+ddI, and FLT+ddI. In contrast, the posttreatment, AZT-resistant virus showed only addition or antagonism by the combinations containing AZT, whereas the synergistic response to the combination of FLT+ddI was preserved. Our study argues for early intervention with combination chemotherapy, since after development of resistance, AZT no longer showed synergy but addition or antagonism in combination with other drugs. After resistance to AZT has developed, combination chemotherapy not involving AZT may offer advantages over continued mono- or combination therapy involving AZT.

Correlation of gingival crevicular fluid proteases with clinical and radiological measurements of periodontal attachment loss

Probing attachment loss and radiographical measurements of bone loss were made on 20 untreated chronic periodontitis patients. At a second visit, gingival crevicular fluid was collected on filter paper strips from the deepest accessible interdental probing site of each tooth. Gingival crevicular fluid volumes were determined and the samples eluted into buffer. Protease activities in the resulting eluates were assayed with peptidyl derivatives of 7-amino-4-trifluoromethyl coumarin (AFC). Cathepsin B/L-like activity was determined with Bz-Val-Lys-Lys-Arg-AFC, elastase-like activity with MeOSuc-Ala-Ala-Pro-Val-AFC, tryptase-like activity with Z-Ala-Ala-Lys-AFC, trypsin-like activity with Z-Gly-Gly-Arg-AFC and dipeptidyl peptidase IV-like activity with Ala-Pro-AFC. Total enzyme activities and enzyme concentrations correlated positively with probing attachment loss and bone loss in linear regression analysis. This was true at both a patient level, using mean patient values, and a site level, using either individual patient or pooled patient data. All of these correlations were highly statistically significant for site comparisons. In inter- and intra-patient comparisons the proportion of significant correlations was greater for total enzyme activity than concentration. Clinical and radiological measurements of attachment loss showed generally similar levels of correlation. Total enzyme activities had good specificity and sensitivity as indicators of attachment loss in this cross-sectional study. The results support further investigation of the diagnostic potential of gingival crevicular fluid proteases in evaluation of the periodontal condition.

Cathepsin B/L-, elastase-, tryptase-, trypsin- and dipeptidyl peptidase IV-like activities in gingival crevicular fluid. A comparison of levels before and after basic periodontal treatment of chronic periodontitis patients

20 chronic periodontitis patients were given a full periodontal examination, including measurements of probing depth, clinical attachment loss, gingival index, bleeding index and plaque index. At a second visit, gingival crevicular fluid (GCF) was collected from the deepest accessible probing site of each tooth. The patients then received scaling, root planing and other appropriate nonsurgical treatment. GCF was collected from the same sites as sampled pretreatment and clinical parameters were measured again. Cathepsin B/L-, elastase-, tryptase-, trypsin-, and dipeptidyl peptidase IV-like activities in GCF samples were determined by fluorimetric assay with peptidyl derivatives of 7-amino-4-trifluoromethyl coumarin. Following treatment, there were reductions in all clinical parameters and all protease activities. Most were statistically significant both on a patient level using average patient values and on a site level using either individual patient or pooled patient data. As in previous pre-treatment comparisons, post-treatment protease levels correlated positively and significantly with the corresponding clinical parameters at patient and site levels. The reductions and correlations were more marked for total enzyme activities than concentrations. GCF protease levels appear to reflect the clinical status of periodontal lesions and may thus be of value in monitoring disease activity.

Cathepsin B/L-, Elastase-, Tryptase-, Trypsin- and Dipeptidyl Peptidase IVLike Activities in Gingival Crevicular Fluid: A Comparison of Levels Before and After Periodontal Surgery in Chronic Periodontitis Patients

Gingival crevicular fluid (GCF) was collected from the deepest probing site of each tooth of 10 chronic periodontitis patients prior to treatment, after scaling and hygiene treatment, and after periodontal surgery. Surgery was carried out at sites which had persistent probing depths in excess of 5 mm. The patients were given a full periodontal examination, including measurements of probing depth, gingival index, bleeding index, and plaque index before each GCF collection. Cathepsin B/L-, elastase-, tryptase-, trypsin-, and dipeptidyl peptidase IV-like activities in the GCF samples were determined by fluorimetric assay with peptidyl derivatives of 7-amino-4-trifluoromethyl coumarin. There were reductions in all clinical parameters and all protease activities after scaling and hygiene treatment and further reductions after periodontal surgery. Decreases were recorded for both total enzyme activities and concentrations. The reductions were statistically significant in inter-patient comparisons using mean patient values and also in most intra-patient comparisons using site data from individual patients. GCF protease levels appear to reflect the clinical status of periodontal lesions and may prove to be of value in monitoring disease activity.

Dipeptidyl peptidase II- and IV-like activities in gingival tissue and crevicular fluid from human periodontitis lesions

Gingival tissue and gingival crevicular fluid were collected from patients with chronic periodontitis. Gel filtration chromatography of crude tissue extracts yielded separate fractions active against Lys-Ala-7-amino-4-trifluoromethyl-coumarylamide (AFC) at acid pH and Gly-Pro-AFC at alkaline pH. The molecular weights, pH optima and inhibitor responses of these activities were consistent with those of dipeptidyl peptidases (DPP) II and IV, respectively. When tested with the same substrates, crevicular fluid was also found to contain DPP II- and IV-like activities with very similar pH profiles and inhibitor responses to those in tissue. The close resemblance suggested that the crevicular fluid enzymes were derived mainly from inflamed gingival tissues. Slight differences in the DPP II-like activities might be explained by the additional presence in crevicular fluid of enzymes from subgingival bacteria. With use of appropriate buffers, a third substrate, Ala-Pro-AFC, gave selective detection of both DPP II- and IV-like activities in tissue and crevicular fluid. Assays with Ala-Pro-AFC had the advantage of greater sensitivity, especially with DPP II-like activity. Raised levels of this enzyme have previously been found in the gingiva of periodontitis patients and thus DPP II-like activity in crevicular fluid might prove of value in monitoring disease activity.

The immediate- and medium-term effects of Meswak on the composition of mixed saliva

Chewing sticks or Meswaks are used for teeth cleaning in many parts of the world. They contain substances that may reduce caries and periodontal disease. The present study consisted of 2 parts. In a short-term experiment, volunteers chewed on an inert eliciting agent (pyrogen-free rubber) and then a piece of Meswak, each for 5 min. For the medium-term experiment, volunteers brushed with either Meswak or a conventional toothbrush 5 x a day for 2 weeks. Saliva produced immediately after chewing Meswak showed statistically significant increases in calcium and chloride, but decreases in phosphate and pH as compared with controls. In the medium-term experiment, saliva samples collected 4 h after the last use of Meswak or toothbrush showed no significant differences in any of the components examined (calcium, magnesium, chloride, phosphate, IgA, IgG, lactate dehydrogenase and aspartate transaminase). Gingival and plaque indices, however, were significantly lower after brushing with Meswak. Salivary calcium promotes mineralization of tooth enamel and chloride inhibits calculus formation. Our results thus indicate that Meswak releases substances into saliva that could improve oral health. Calcium and chloride values were similar to those of controls after 4 h and thus frequent use of Meswak may be necessary to maintain a favorable salivary environment.

Cathepsin B/L-, elastase-, tryptase-, trypsin- and dipeptidyl peptidase IV-like activities in gingival crevicular fluid: correlation with clinical parameters in untreated chronic periodontitis patients

20 untreated chronic periodontitis patients were given a full periodontal examination, including measurements of probing depth (PD), clinical attachment loss (CAL), gingival index (GI), bleeding index (BI) and plaque index (Pl.I.). At a second visit, gingival crevicular fluid (GCF) was collected on filter paper strips from the deepest accessible probing site of each tooth. GCF volumes were determined and the samples eluted into buffer. Protease activities in the resulting eluates were assayed with peptidyl derivatives of 7-amino-4-trifluoromethyl coumarin (AFC). Cathepsin B/L-like activity was determined with Bz-Val-Lys-Lys-Arg-AFC, elastase-like activity with MeOSuc-Ala-Ala-Pro-Val-AFC, tryptase-like activity with Z-Ala-Ala-Lys-AFC, trypsin-like activity with Z-Gly-Gly-Arg-AFC and dipeptidyl peptidase (DPP) IV-like activity with Ala-Pro-AFC. Total enzyme activities and enzyme concentrations both correlated positively with all clinical parameters in linear regression analysis. This was true on both a patient level, using mean patient values, and a site level, using either individual patient or pooled patient data. Most of these correlations were statistically significant, although the proportion was greater for total enzyme activity than concentration. With total activities, correlations with different enzymes and parameters generally followed the order: cathepsin B/L-greater than elastase- greater than DPP IV- greater than trypsin- greater than tryptase-like activity and PD greater than CAL greater than GI greater than BI greater than Pl.I respectively. Total enzyme activities had good diagnostic specificity and sensitivity as predictors of clinical parameters in this cross-sectional study, suggesting that GCF proteases might provide useful information on the periodontal condition.

Cathepsin B- and L-like activities at local gingival sites of chronic periodontitis patients

The cysteine proteinases cathepsins B and L have the potential to degrade connective tissue in chronic periodontitis and this may progress episodically at individual tooth sites. The activities of cathepsin B- and L-like proteinases in homogenised gingival tissue from control and periodontitis patients were measured biochemically using the selective peptide substrate Z-Phe-Arg-AFC and the selective cathepsin L inhibitor Z-Phe-Phe-CHN2. Each tooth site was divided, where appropriate, into gingival tissue and granulomata. These were assayed separately and the measurements related to the DNA and protein contents of the tissues. Enzyme activity in healthy control tissue was significantly lower than in diseased tissue. Enzyme activity in gingival tissue and total tissue from periodontitis patients decreased with increasing pocket depth, clinical attachment level, gingival index and bleeding index whilst cathepsin B activity in granulomata increased with increasing pocket depth and clinical attachment level but not with increasing gingival index or gingival bleeding index. Mean enzyme activity in gingival tissue was 1.6-2.8 times greater than in granulomata. Mean patient enzyme activity in diseased patients did not correlate positively with their mean pocket depth, clinical attachment level, gingival index or gingival bleeding index. These results are best explained by the probable cellular origins of the enzymes and the likely influence of their serum and tissue inhibitors during the disease process.