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Biomedical subjects

J Slots

Publications and source records attributed to J Slots.

At least 145 records · Page 8Linked to original sources
PubMed1990

Genetic approach to the study of epidemiology and pathogenesis of Actinobacillus actinomycetemcomitans in localized juvenile periodontitis.

Actinobacillus actinomycetemcomitans isolates from periodontal pockets were examined for restriction fragment-length polymorphism using a characterized 4.7-kb DNA probe. A total of 6 patterns of RFLP was found in 133 isolates originating from 12 subjects. No relatedness was found between RFLP types and serotypes. Different periodontal sites within the same subject and different individuals within the same family sometimes showed only one type of A. actinomycetemcomitans RFLP. When members among the same family showed 2 RFLP types, children were always infected with the A. actinomycetemcomitans strains found in at least one of the parents. These findings support the concept of familial spread of A. actinomycetemcomitans. A. actinomycetemcomitans RFLP type B, corresponding to reference strain JP2, seems to be particularly virulent, as indicated from the presence of RFLP type B in 3 subjects who converted from a healthy periodontal state to localized juvenile periodontitis. RFLP type B was not detected in any of the 21 A. actinomycetemcomitans-infected patients with adult periodontitis. The RFLP method seems to be useful in determining the epidemiology and possibly the potential virulence of periodontal strains of A. actinomycetemcomitans.

Actinobacillus↗
PubMed1990

Antibiotics in periodontal therapy: advantages and disadvantages.

Antibiotic treatment of periodontitis aims at eradicating or controlling specific pathogens. Prime candidates for antibiotic therapy are patients with recently diagnosed active periodontitis or a history of recurrent disease who fail to stabilize following mechanical/surgical therapy. Since a variety of microbes with differing antimicrobial susceptibility profiles may cause periodontitis, selection of antimicrobial agents should be based on proper microbial diagnosis and sensitivity testing, as well as consideration of the patient's medical status. The risk of treating chemotherapeutically solely on the basis of clinical features, radiographic findings or a limited microbiological analysis, is failure to control the pathogens or overgrowth of new pathogens. A review of published papers reveals that appropriate systemic antibiotic therapy may enhance healing in patients with recent or high risk of periodontal breakdown. Systemic antibiotic therapy seems more predictable than topical administration in eradicating periodontal pathogens from deep periodontal pockets. Several promising antimicrobial agents for periodontitis treatment need testing in placebo-controlled, double-blind, randomized clinical trials.

Anti-Bacterial Agents↗
PubMed1990

Staphylococci in human periodontal diseases.

The occurrence of subgingival staphylococci was determined in 506 individuals with advanced adult periodontitis, 108 with early-onset periodontitis, 13 with localized juvenile periodontitis, 18 with gingivitis, and 13 with 20 failing osseointegrated titanium dental implants. Subgingival samples were collected with paper points and transported in VMGA III. The bacterial samples were plated on Staphylococcus 110 medium which was incubated in 10% CO2, and on enriched brucella blood agar, which was incubated anaerobically. Staphylococcal isolates from 94 adult periodontitis subjects were speciated using the API STAPH Trac micromethod kit system and the Bacto Staph latex agglutination test for coagulase activity. Staphylococcus epidermidis comprised 45.8% and Staphylococcus aureus 22.3% of total staphylococcal isolates. At 1 microgram/ml, in vitro resistance by staphylococci was found to tetracycline (14.4% of isolates), penicillin (4.9%), erythromycin (12.1%), and metronidazole (31.9%). Subgingival staphylococci were isolated from approximately 50% of gingivitis and periodontitis patients. No statistically significant differences were found between these patient groups in the prevalence or mean proportions of staphylococci recovered. "Periimplantitis" lesions exhibited significantly higher proportions of staphylococci (15.1%) than gingivitis (0.06%) or periodontitis (1.2%) lesions. Staphylococci may play a role in some failing osseointegrated dental implants.

Adolescent↗
PubMed1990

Probe-specific DNA fingerprinting applied to the epidemiology of localized juvenile periodontitis.

Although Actinobacillus actinomycetemcomitans has been recognized as a primary etiological agent in localized juvenile periodontitis, questions remain concerning the source of infection, mode of transmission, and relative virulence of strains. DNA fingerprinting analysis, using a randomly cloned chromosomal DNA fragment as a probe, revealed that previously characterized strains of A. actinomycetemcomitans displayed significant restriction site heterogeneity which could be applied to the typing of clinical isolates of this bacterium such that individual strains or variants could be traced within subjects from localized juvenile periodontitis families. Hybridization data derived from an analysis of bacterial isolates obtained from families participating in an ongoing longitudinal study of the disease showed that a single individual could be infected with more than one strain or variant of A. actinomycetemcomitans and that various members of the same family could harbor different strains or variants of the bacterium. In several cases the clinical isolates were matched to characterized laboratory strains by comparing hybridization patterns generated by digestion of the DNA with several restriction enzymes in independent reactions. Thus, probe-specific DNA fingerprinting of A. actinomycetemcomitans will permit us to determine if particular strains or variants are frequently associated with sites of periodontal destruction. Attention could then be focused on determining the virulence properties of those strains or variants that have in vivo significance.

Actinobacillus↗
PubMed1990

Prevalence and antimicrobial susceptibility of Enterobacteriaceae, Pseudomonadaceae and Acinetobacter in human periodontitis.

This study examined the occurrence of non-oral gram-negative facultatively anaerobic rods in advanced adult periodontitis. Speciation and in vitro antimicrobial susceptibility testing was performed using the MicroScan micromethod system. A total of 42 taxa of Enterobacteriaceae, Pseudomonadaceae and Acinetobacter were isolated from 427 of 3,050 (14.0%) patients. In 159 (5.2%) patients, these organisms comprised more than 5% of the cultivable subgingival microflora. Enterobacter cloacae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Klebsiella oxytoca and Enterobacter agglomerans accounted for more than 50% of all strains isolated. Virtually all study strains demonstrated high in vitro susceptibility to ciprofloxacin, but exhibited variable susceptibility patterns to 18 other antimicrobial agents tested. In 3 "refractory" periodontitis patients heavily infected with enteric rods, systemic ciprofloxacin therapy (500 mg BiD for 10 days) led to resolution of the subgingival infections and improved clinical periodontal status. The present findings indicate that 5% of severe periodontitis lesions may harbor high levels of non-oral, gram-negative, facultatively anaerobic rods. Systemic ciprofloxacin appears to be capable of eradicating these potential pathogens from deep periodontal pockets.

Acinetobacter↗
PubMed1990

Subgingival occurrence of enteric rods, yeasts and staphylococci after systemic doxycycline therapy.

The occurrence of subgingival enteric rods, yeasts and staphylococci (pre-treatment and post-treatment) was examined in 21 adult periodontitis patients receiving mechanical periodontal therapy and systemic doxycycline (200 mg on first day, then 100 mg/day for 20 days). Subgingival samples obtained prior to, and 2 weeks and 4 weeks after completion of the antibiotic therapy were transported in VMGA III and plated onto TSBV (for enteric rods and yeasts) and Staphylococcus 110 media. At baseline, small numbers of enteric rods (3 patients), yeasts (5 patients) and staphylococci (11 patients) were detected subgingivally. After the antibiotic therapy, more than 10-fold increases were seen in subgingival numbers of Enterobacter aerogenes (2 patients), Escherichia coli (1 patient), Candida albicans (2 patients), and staphylococci (11 patients). These findings demonstrating that systemic doxycycline therapy may result in at least temporary subgingival overgrowths of enteric rods, yeasts and staphylococci, may indicate the risk of frequent use of tetracycline in periodontal therapy.

Adult↗
PubMed1990

In vitro antimicrobial sensitivity of enteric rods and pseudomonads from advanced adult periodontitis.

The prevalence and in vitro antimicrobial sensitivity of isolates of enteric rods and pseudomonads was examined in 844 adult periodontitis patients. These organisms were recovered from 13.5% of the study subjects. Ciprofloxacin exhibited the highest inhibitory activity of the 14 oral antimicrobial agents tested. Beta-lactam antibiotics were largely ineffective, and tetracycline failed to inhibit most Pseudomonas species. In vitro sensitivity data suggest that a subgingival microbiota comprising mainly streptococci would result from therapy that combined ciprofloxacin and metronidazole. Since streptococci may inhibit the growth of several putative periodontal pathogens, populations of "beneficial" streptococci in the periodontal pocket might constitute a very attractive therapeutic outcome. Controlled clinical studies are needed to clarify the possible role of ciprofloxacin in the treatment of destructive periodontitis.

Adult↗
PubMed1990

Age and sex relationships of superinfecting microorganisms in periodontitis patients.

The occurrence by age and sex of subgingival enteric rods and pseudomonads, yeasts, and staphylococci was studied in 3075 "refractory" periodontitis patients referred for microbiological analysis. Each subject contributed a pooled subgingival sample obtained from 3 deep periodontal pockets with paper points. Selective and nonselective media and commercial identification kit systems were used for microbial isolation and speciation. Females constituted about 60% of the study subjects, and almost one-third of all patients were in their forties. Females (47.3%) showed a higher prevalence of the study organisms than males (43.9%). Older females (15.9%) and males (15.3%) revealed significantly higher prevalences of enteric rods and pseudomonads than younger individuals (10.9%), and older infected females yielded significantly higher viable counts than younger infected females. The sexes demonstrated a similar prevalence of staphylococci (about 28%), but younger infected females and males showed significantly higher viable counts than older infected individuals. No sex or age relationships were found for yeasts (about 14% of individuals infected). The high level of subgingival enteric rods and pseudomonads in some individuals may be important in the pathogenesis of geriatric and other forms of periodontitis and may have therapeutic implications.

Adolescent↗
PubMed1990

Leukocidal activity of staphylococci isolated from human periodontal lesions.

Staphylococci isolated from subgingival samples of patients with advanced periodontitis were tested for leukocidal activity. Intact organisms, bacterial sonicates or bacterial culture supernatants were incubated with human neutrophils that had been prelabeled with 51chromium. The majority of Staphylococcus aureus periodontal isolates provoked dose-dependent extracellular release of the radiolabel. By contrast, other strains of staphylococci had marginal or no demonstrable leukocidal activity. Leukocidal activity was heat-sensitive and was neutralized by horse anti-leukocidin antibodies. The results indicate that S. aureus colonizing human periodontal lesions elaborate a leukocidin that may conceivably destroy neutrophils that emigrate into the gingival region. This could adversely affect the overall status of this antimicrobial defense system in the gingival area and contribute to the pathogenicity of S. aureus as well as other potential periodontopathic organisms.

Chromium Radioisotopes↗
PubMed1990

Effect of root debridement on the elimination of Actinobacillus actinomycetemcomitans and Bacteroides gingivalis from periodontal pockets.

The aims of this 6-month longitudinal study were: (1) to investigate to what extent root debridement of pockets in adult periodontitis will reduce the subgingival presence of Actinobacillus actinomycetemcomitans, Bacteroides gingivalis and some other bacterial groups; (2) to relate the microbiological results following debridement to clinical measurements of healing. 16 patients and a total of 111 periodontally involved sites with probing depth greater than or equal to 6 mm served for the study. Duplicate subgingival microbial samples and duplicate clinical recordings were obtained 1 week apart at baseline and at 6 months following supra- and subgingival debridement. The results demonstrated reductions of the mean total viable counts and reductions of the mean counts of several of the cultured groups of micro-organisms coupled with significant improvements of mean clinical measurements. B. gingivalis was eliminated from a majority of infected subgingival sites. A. actinomycetemcomitans, on the other hand, still remained after therapy in a high proportion of sites initially infected with this microorganism. Subgingival persistence of A. actinomycetemcomitans appeared to be associated with a reduced healing response following debridement. Further studies are needed to clarify why A. actinomycetemcomitans is poorly eliminated following debridement. Also, the long-term clinical significance of the subgingival perseverance of A. actinomycetemcomitans needs to be elucidated.

Actinobacillus↗
PubMed1990

On the inability of root debridement and periodontal surgery to eliminate Actinobacillus actinomycetemcomitans from periodontal pockets.

In a previous study, we observed that root debridement was inefficient in eliminating Actinobacillus actinomycetemcomitans from adult periodontitis lesions. The present report describes the effects on A. actinomycetemcomitans of subsequent treatments of 6 patients that had at least 2 separate sites still harboring A. actinomycetemcomitans 6 months following debridement. 1 site or more in each individual was treated with renewed root debridement and at least 1 other site was treated by surgical excision of the gingival tissue. The results indicated that retreatment with either repeated root debridement or with surgical excision of the gingival tissue was not more effective in eliminating A. actinomycetemcomitans than initial debridement. The possible reasons for this limited therapeutic effect on the subgingival presence of A. actinomycetemcomitans are discussed.

Actinobacillus↗
PubMed1990

5-year follow up of periodontal intraosseous defects treated by root planing or flap surgery.

Intraosseous, periodontal defects in 12 subjects initially treated by root planing alone (21 defects) or by flap surgery (21 defects) were monitored during a 5-year postoperative interval. Maintenance therapy during this interval was limited to reinforcement of oral hygiene and tooth polishing every 6 months. No subgingival instrumentation was performed at the defect sites. Longitudinal clinical measurements demonstrated that surgically-treated lesions responded with somewhat more reduction of probing depth and more gain of probing bone level than root-planed lesions. Mean gains of probing attachment level were similar for the 2 treatments. Some relapse of the clinical conditions could be observed towards the end of the 5-year observation interval compared to the results at year 1 and year 2. However, the majority of defects subjected to either treatment showed 60-month recordings of probing attachment and probing bone levels equal to or slightly improved compared to those at baseline. Counts from cultures of subgingival, microbial samples were obtained at 42, 48 and 60 months. No significant difference between the 2 therapies was observed for the investigated groups of micro-organisms.

Adult↗
PubMed1990

Actinobacillus actinomycetemcomitans and Bacteroides intermedius in human periodontitis: age relationship and mutual association.

This study examined age relationships and mutual interrelationships between cultivable Actinobacillus actinomycetemcomitans and Bacteroides intermedius in 1624 periodontitis patients, 15 to 89 years of age. Each subject contributed a pooled subgingival sample, obtained from 3 deep periodontal pockets with paper points. A. actinomycetemcomitans occurred with higher prevalence (74%) and mean recovery (7% in culture-positive patients) in patients less than 25 years old than in adult and geriatric patients (prevalence about 31%; mean recovery about 1%). The organism was detected in 85% of localized juvenile periodontitis patients. B. intermedius was recovered from 45% of the study subjects, averaged about 7% of total isolates in positive patients, and showed no predilection for any age group. As determined from predicted and observed values for A. actinomycetemcomitans and B. intermedius, occurring alone and in combination, no synergistic or antagonistic relationships between the organisms could be delineated with respect to subgingival colonization. The therapeutic implication of these findings is discussed.

Actinobacillus↗
PubMed1989

Experimental infections by Bacteroides gingivalis in non-immunized and immunized rabbits.

The interactions between Bacteroides gingivalis and systemic antibodies were studied in tissue cages implanted in the backs of New Zealand white rabbits. Infectivity was evaluated according to clinical signs and to leukocyte and bacterial counts in material aspirated from the tissue cages. Pre- and post-inoculation antibody levels to sonicated whole bacterial cells were determined by enzyme-linked immunosorbent and agar immunodiffusion assays. Rabbits immunized against B. gingivalis and then challenged with pure cultures of B. gingivalis revealed complete elimination or markedly lower postinoculation bacterial counts and considerably weaker tissue reactions than non-immunized animals. B. gingivalis co-inoculated with Actinobacillus actinomycetemcomitans caused significantly more severe infections than observed in monoinfected animals. The present results suggest that the immune system acting through systemic antibodies and/or cellular mechanisms may modulate the pathogenic potential of infecting periodontal pathogens.

Animals↗
PubMed1989

Immunomodulatory effects of Bacteroides products on in vitro human lymphocyte functions.

Bacteroides spp. have been implicated in the pathogenesis of several diseases, including periodontal diseases. In this study sonic extracts of 6 Bacteroides spp. were examined for their abilities to alter human lymphocyte function. We found that soluble extracts from Bacteroides intermedius, Bacteroides endodontalis, Bacteroides asaccharolyticus, Bacteroides melaninogenicus, and to a lesser degree Bacteroides loescheii, caused dose-dependent inhibition of human lymphocyte responsiveness to both mitogens and antigens. Suppression involved altered DNA, RNA and protein synthesis as well as immunoglobulin production. In contrast, Bacteroides gingivalis did not suppress these responses; instead, it stimulated lymphocyte proliferation and enhanced immunoglobulin production. It has been proposed that impaired host defense may play a pivotal role in the pathogenesis of many infections. The data presented in this paper suggest that microbial mediated immunosuppression may conceivably alter the nature and consequences of host-parasite interactions in periodontal disease.

Bacteroides↗
PubMed1989

Clinical and microbiological characteristics of treated periodontitis patients on maintenance care.

A population of 98 adults previously treated for moderate to advanced adult periodontitis and currently maintained in a recall program for at least one year were recruited for this study. The ultimate purpose of the study is to determine whether the presence of Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, and Bacteroides intermedius in selected periodontal sites can predict the future clinical course of these patients, particularly with respect to disease recurrence. This report presents the clinical design of the study which allows comparisons between sites positive and negative for these species in infected patients, and between sites in infected patients and comparable sites in non-infected patients. In addition, some base line clinical and microbiological data for these patients are presented. The distribution of PII and GI scores tended to be highest for molars, with the remaining teeth having similar scores. Probing depth measurements were greater for mesio-distal than oro-vestibular recordings. A bilaterally symmetrical pattern of increasing probing depth was noted from the midline distally on mesio-distal as well as oro-vestibular surfaces. Sites positive for the target organisms listed above tended to have greater probing depths (mean: 4.14 +/- 0.1 mm) than non-infected sites in the same patients (mean: 3.76 +/- 0.1 mm) or comparable sites in non-infected patients (mean: 3.54 +/- 0.1 mm).

Actinobacillus↗