Enzyme-linked immunosorbent assay for human IgG, IgA, and IgM antibodies to antigens from anaerobic cultures of seven oral bacteria.

Monocultures of 7 oral bacteria were grown anaerobically, and antigens were partially purified from the supernatant fluids by gel filtration. Isoelectric focussing showed that the antigen fractions contained PAS-positive material and proteins focussing between pH 3.5 and pH 5.5. Specific activity against the 7 antigen fractions was observed for IgG, IgA, and IgM in serum from patients with periodontal disease by means of enzyme-linked immunosorbent assay (ELISA). Conditions for antigen coating in ELISA were studied, and large variations with regard to optimal concentration were found among the 7 fractions. The ELISA readings were virtually unaffected by increasing the pH of the coating buffer from 5 to 9. Addition of sheep serum to the incubation buffer was disadvantageous as the serum showed moderate antibody activity to the 7 antigen fractions, and human serum apparently contained IgM antibodies to sheep IgG. Addition of 0.5% BSA improved the reproducibility of ELISA considerably, although the sensitivity was somewhat decreased.

Influence of parenteral immunization in rabbits on the penetrability of oral mucosa for macromolecules.

It should not be overlooked that serum-derived antibodies may normally play an important role in mucosal homeostasis conducive to health. Thus, protection against at least some bacterial components may be an antibody-mediated function during the initial phase of gingivitis (21). Nevertheless, Auer demonstrated in 1920 that mild inflammation can be severely aggravated by local accumulation of serum-derived antibodies combined with a systemic supply of the corresponding antigen (2); subsequent studies have shown that this holds true also when the antigen is topically applied (11,14). Theoretically, the initial gingival lesion is an ideal situation for the development of a so-called "Auer-phenomenon", due to continuous supply of antigens from dental plaque and food. This possible hazard of circulating antibodies must be taken into account when immunoprophylaxis is attempted by parenteral vaccines.

Periodontal disease mechanisms in immunocompromised patients.

Deficiency in the number and function of phagocytes is associated with gingival inflammation and periodontitis. A hereditary deficiency in membrane glycoproteins involved in granulocyte adherence causes impaired chemotaxis, reduced phagocytosis and periodontal problems. Virus infections of antigen-presenting cells interfere with immune responses and lead to seriously increased susceptibility to infections with bacteria which cause no problems in normal patients. Increased levels of IgG antibodies may limit penetration of antigens in the tissues, but at the cost of local inflammation and tissue injury. Mucosal inflammatory disease with increased local formation of IgG is more frequent in IgA deficient patients. The immunological homeostasis depends on a balance between the respective classes and subclasses of antibodies. Deficiencies in the IgA system may contribute to a disturbed balance of the humoral immune response to critical antigens from oral bacteria. A disproportional increase in IgG1 and IgG3 antibodies may persistently activate complement, stimulate the inflammatory activity and cause tissue injury.

Fc-binding components: a virulence factor in Actinobacillus actinomycetemcomitans?

Actinobacillus actinomycetemcomitans (ATCC 33384) can produce and release components that bind to the Fc part of IgG. Fc-binding components were observed in whole bacteria, capsular material and medium from broth cultures. The components were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotted with biotinylated Fc-fragments and myeloma proteins. In a phagocytosis assay with human granulocytes and sheep erythrocytes, preincubation of opsonized erythrocytes with protein A reduced phagocytosis by 90%. In contrast, preincubation of the opsonizing antibody with medium components from a culture of A. actinomycetemcomitans enhanced the opsonizing effect of the antibody. The enhanced binding of erythrocytes may be caused by formation of aggregates between opsonizing antibody and bacterial Fc-binding components. Aggregated IgG can bind to low-affinity Fc gamma II and gamma III receptors that cannot bind monomeric IgG. Release of Fc-binding components from bacteria may contribute to the periodontal lesion through interference with the phagocytic activity of granulocytes and with the complement system. Fc-binding components may also interfere with downregulation of the B-cell response.

Serum antibodies and loss of periodontal bone in patients with rheumatoid arthritis.

The number of teeth, % of alveolar bone loss, serum IgG, and serum antibodies to Bacteroides gingivalis, Capnocytophaga ochracea and Eubacterium saburreum were recorded in 37 patients diagnosed with rheumatoid arthritis (RA) and in an age- and sex-matched control group of 37 individuals free from RA. The RA group had a significantly increased loss of teeth and loss of alveolar bone compared to the control group. The RA patients also had a significantly increased level of serum IgG. In the total material, 26% of the variation in loss of alveolar bone was accounted for by age, diagnosis of rheumatoid arthritis, and levels of antibodies against B. gingivalis and E. saburreum. In the RA group, 48% of this variation was accounted for by age, total serum IgG and IgG antibodies to B. gingivalis and E. saburreum.

Serum antibody levels to 4 periodontal pathogens remain unaltered after mechanical therapy of juvenile periodontitis.

Serum antibody titers to Actinobacillus actinomycetemcomitans (A.a.) Y4, Bacteroides gingivalis, Capnocytophaga ochracea and Eubacterium saburreum were determined with an enzyme immunoassay in 12 patients with juvenile periodontitis (JP) at the beginning of treatment and 16 to 32 months later after clinically successful mechanical therapy without antibiotics. The values were compared to corresponding data obtained from 26 age- and sex-matched individuals with a healthy periodontium. 6 JP patients had significantly increased levels of IgG and IgA antibodies to A.a. and 2 patients had increased IgG and IgA antibodies to C.ochracea. About 75% of the JP patients had a level of IgG antibody to B.gingivalis and E.saburreum which was more than one SD lower than the mean of the healthy controls, and in the IgA class 80-100% had such decreased levels of antibodies to these bacteria. In the IgM class, the JP patients by and large had normal levels of antibodies to the 4 bacteria. After treatment, antibodies to A.a. had decreased in only 3 patients, but the levels were still significantly higher than in healthy controls. Minimal alterations were observed in the levels of antibodies to B.gingivalis, C.ochracea and E.saburreum after treatment.

[Electrostatic air filters for dental practice]. / Elektrostatisk luftfilter for tannlegepraksis

The filtrering effect of an electrostatic filtrattion equipment (Vortronic mod. 75) for air filtration was examined by sampling the air in a general dental practice by means of a Casella Slit Sampler for Airborne Bacteria (C. F. Casella & Co. Ltd., London). A reception, a sterilization, two treatment chairs and a resting cabinet were seperated by 180 cm high walls in a rectangular room of 33 m2 and with an air volume of approximately 80 m3. The staff including one dentist and one or two assistents worked from 8 a.m. till 4 p.m. with a 30 min. lunch break. A mean of 17 patients visited the practice every day. The electrostatic filter was placed in front of one of the treatment chairs and the slit sampler was, for one period, placed at a distance of 5 m from the filter. In the next period both filter and slit sampler were placed within 140 cm from the treatment chair. The air was sampled at noon and at 4 p.m. Micro-organisms from the air samples were cultured on blood agar by incubation at 37 degrees C for 48 hours. After incubation all colonies visible to the eye were counted. A total of 36 air samples were examined. Without filtration of the air the bacterial contamination amounted to 14 cultivable organisms per ft3 air at noon and 54 organisms per ft3 at 4 p.m. The filtration equipment proved to reduce the air contamination to 6 cultivable organisms per ft3.

Occasional binges by moderate drinkers: implications for birth outcomes.

We investigated the effects of occasional alcohol binges on birth outcomes in a cohort of live singletons born to 709 moderate drinkers recruited from a Seattle, WA, health maintenance organization before their sixth month of pregnancy. We compared infants of women with one or more binges in the month before pregnancy or in the first two trimesters with those whose mothers reported no binges in either period. Mean values of birthweight, length, head circumference, gestational age, intrauterine growth, and Apgar scores did not differ notably between the two groups. The risk of having an adverse neonatal discharge diagnosis initially appeared lower in infants of binging mothers, but this difference vanished after recategorization of the variable and control for confounding. Our results indicate that occasional binges, during a broad window of exposure and among otherwise moderate drinkers, do not adversely affect the birth outcomes examined here.

Fc gamma-binding bacteria in periodontal lesions.

The proportion of bacteria exhibiting surface Fc gamma-binding proteins was determined in periodontal pockets of 20 patients diagnosed with periodontal disease and in subgingival areas of 20 patients without periodontal lesions. Bacterial smears were examined by fluorescence microscopy based on DNA staining (Hoechst 33256) and staining of Fc gamma-binding proteins by human biotin-labelled Fc gamma and Texas red-conjugated streptavidin. Fc gamma-binding proteins were observed in all smears from the patients diagnosed with periodontitis, and in a majority of the smears high proportions of the bacteria were positive for Fc gamma-binding proteins. In contrast, most smears from patients without periodontal lesions included low or undetectable proportions of bacteria with Fc gamma-binding proteins.

Salivary IgG, a parameter of periodontal disease activity? High responders to Actinobacillus actinomycetemcomitans Y4 in juvenile and adult periodontitis.

The concentration of salivary IgG and IgA and the levels of salivary IgG and IgA antibodies to Actinobacillus actinomycetemcomitans Y4 were measured by ELISA in 205 persons including patients with juvenile and adult periodontitis as well as healthy subjects. Compared to the concentration observed in subjects with a healthy periodontium, a significantly increased concentration of salivary IgG was found in 34% of the patients with moderate adult periodontitis and in 57% of the patients with severe adult periodontitis. The level of salivary IgA was less influenced by the periodontal condition. The level of salivary IgG antibody to A. actinomycetemcomitans was significantly elevated in 55% of the patients with untreated juvenile periodontitis and in 28% of the patients treated for JP. 28% of the patients with adult periodontitis had a significantly elevated level of IgG antibody to A. actinomycetemcomitans Y4. Significantly elevated levels of IgA antibody to this bacteria was found less frequently, 27% in untreated JP, 20% in treated JP and 17% in adult periodontitis.

Antigens released from four oral bacteria in periodontitis.

Antigens fractionated from cultures of four oral bacteria were tested for binding of serum IgG, IgA and IgM from patients in early and established phase of periodontitis. Bacteroides gingivalis and A.actinomycetemcomitans released antigens that discriminated between serum from individuals with or without periodontitis. The discriminating antigens ranged from 10 to 43 kDa and included neutral sugar and protein but no lipids. Significantly increased levels of IgG and IgA antibodies to the antigens released from B. gingivalis were detected before bone loss was seen and predicted such disease progression.

Increased levels of soluble Fc gamma receptor III in gingival fluid from periodontal lesions.

Enzyme-linked immunosorbent assay was used for determination of the concentration of soluble Fc gamma receptor III (Fc gamma RIII) in 40 samples of gingival fluid obtained from periodontal pockets in 30 patients with periodontitis. The assay was based on a monoclonal immobilized antibody binding Fc gamma RIII and a polyclonal Fc gamma RIII rabbit antibody for its quantification. The results indicate a substantially increased concentration of soluble Fc gamma RIII in gingival fluid as compared to the serum level. This increased concentration of soluble Fc gamma RIII may interfere with phagocytosis and immune homeostasis in the periodontal lesions.

Statistical significance testing in the American Journal of Epidemiology, 1970-1990.

Despite persistent controversy over statistical significance testing and the obligation for all researchers to adopt some position on the issue, until now, practices of epidemiologists have not been examined thoroughly. Articles in the American Journal of Epidemiology around the years 1970, 1980, and 1990 were evaluated and divided into infectious disease epidemiology, cancer epidemiology, and cardiovascular disease epidemiology, with a minimum of 25 articles per topic area and time period. Presentation of significance test results and confidence intervals was evaluated in the abstracts, results text, and results tables, as was the degree of reliance on significance testing in the discussion section. Significance testing grew markedly in infectious disease epidemiology and was consistently high in cardiovascular disease and cancer epidemiology. Confidence intervals were virtually absent in 1970 and became ubiquitous (particularly in cancer epidemiology) by 1990, when the most common practice was to provide confidence intervals in results tables and to emphasize statistical significance tests in results text. Reliance on statistical significance tests in interpretation grew steadily in infectious disease, sustained a high level in cardiovascular disease, and declined after 1980 in cancer epidemiology. At present, dual presentation of confidence intervals and statistical test results is dominant.

Soluble Fc gamma receptors in periodontal lesions.

Soluble Fc gamma-binding components were detected in gingival fluid from periodontal lesions by incubation with biotinylated human Fc gamma fragments. Fc gamma III receptor was identified by incubation of gingival fluid with monoclonal antibody. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western transfer showed that most of the Fc gamma-binding components had minimal mobility in a 4-15% gradient gel under nonreducing conditions. Under reducing conditions, the main band of Fc gamma-binding components in gingival fluid migrated corresponding to protein A of 49 kDa. The pattern of Fc gamma-binding components was similar in serum and gingival fluid except for the observation in gingival fluid of Fc gamma-binding components migrating like standard proteins of 19 to 20 kDa, a size that corresponds to the polypeptide part of Fc gamma II receptor and Fc gamma III receptor.

Comparison of bone resorption at one-step and two-step mandibular endosseous implants in dogs.

Endosseous dental implants have been inserted into dog jaw bone following two different implantation principles. Using the two-step procedure, the implant is left submerged, covered by the mucoperiosteum for a healing period, before communication with the oral cavity is established. According to the one-step procedure, this communication is established peroperatively. In order to estimate radiographically the degree of bone resorption following the two-step as compared to the one-step procedure, the former was used on the right and the latter on the left side of the mandible in two dogs. Periodic identical intraoral radiographs revealed bone resorption in the neck area of all implants. After a 1-yr period with bilateral bridges, the vertical resorption varied between 3 and 5 mm. No difference was found between the two methods concerning this bone resorption. The observation seems to be contrary to the general opinion on the matter, and pertinent investigations with the present model will be performed in a human material.

Implant-tissue interface of endosseous dental implants in dogs. validity of clinical evaluation methods.

Plaque and gingival bleeding were scored and probing, radiography, and histologic methods were used to evaluate clinical methods for estimating alterations of supporting structures at functioning endosseous dental implants. Twelve implant abutment posts in three Labrador retriever dogs were assessed. The observation period was 3 months of submerged healing followed by 6 months in function. In the presence of daily gingival cleaning, both plaque and gingival bleeding scores were reduced on implant abutments. No correlation was found between gingival scores and the degree of bone resorption. The correlation between probing and radiographic measurements was studied by comparing 136 parallel measurements. The average difference was 0.4 mm. Discrepancies were observed when evaluating bone loss that reached the shoulder area. Better accordance was obtained when moderate (2 to 4 mm) or extensive (6 to 8 mm) resorption was assessed. Histologic evaluation indicated alternating regions of implant-bone contact and fibrous encapsulation. Progressive infiltrates were observed in the permucosal area, sometimes extending into the deeper parts of the supporting bone. A combination of probing and radiographic measurements seems to give the most reliable information about the level of bone support and is recommended to be included in routine control of implant abutments.