Search PubMed⌕ Search

Biomedical subjects

S W Cox

Publications and source records attributed to S W Cox.

At least 37 records · Page 2Linked to original sources
PubMed1997

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.

Aggregatibacter actinomycetemcomitans↗
PubMed1997

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.

2-Naphthylamine↗
PubMed1997

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.

Abscess↗
PubMed1996

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.

Bacteria↗
PubMed1996

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.

Adult↗
PubMed1996

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.

Adult↗
PubMed1996

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.

Adhesins, Bacterial↗
PubMed1996

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.

Animals↗
PubMed1995

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.

Adult↗
PubMed1995

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 Proteins↗
PubMed1995

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.

Adult↗
PubMed1995

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)

Chronic Disease↗
PubMed1994

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.

Acquired Immunodeficiency Syndrome↗
PubMed1994

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.

2-Naphthylamine↗
PubMed1993

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.

Abnormalities, Drug-Induced↗
PubMed1993

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.

Antiviral Agents↗
PubMed1993

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.

Aggregatibacter actinomycetemcomitans↗