Search PubMed⌕ Search

Biomedical subjects

J de Graaff

Publications and source records attributed to J de Graaff.

At least 55 records · Page 3Linked to original sources
PubMed1994

Quantitative aspects of the subgingival distribution of Actinobacillus actinomycetemcomitans in a patient with localized juvenile periodontitis.

The subgingival microflora in a patient with localized juvenile periodontitis was studied. Of the 97 sites investigated, 28 (29%) showed attachment loss. A correlation was found between the number of Actinobacillus actinomycetemcomitans cells and the clinical attachment level and probing pocket depth. Of the 97 test sites, 70 (73%) were positive for A. actinomycetemcomitans. Of the total number of A. actinomycetemcomitans cells isolated from this patient, more than 99% were found at sites with attachment loss, < 1% being present at sites without attachment loss. The mean percentage of A. actinomycetemcomitans was 21.2% at sites with attachment loss and 0.45% at sites without attachment loss. The distribution of Porphyromonas gingivalis showed a symmetrical pattern, being present at the 1st molar and 2nd premolar sites in all quadrants and at the lower incisor sites. This species was absent at multiple sites showing overt attachment loss.

Adult↗
PubMed1994

Short-term effect of full-mouth extraction on periodontal pathogens colonizing the oral mucous membranes.

In this study, we investigate the prevalence of selected periodontal pathogens on the oral mucous membranes before and after full-mouth tooth extractions in patients with severe periodontitis. 8 patients were microbiologically examined 2 x before and 2 x after extraction; several locations on the oral mucous membranes, saliva, supra- and subgingival plaque, were sampled. Besides their presence in subgingival plaque, we detected before extraction on the mucous membranes Actinobacillus actinomycetemcomitans in 2 patients (mean 0.03%), Porphyromonas gingivalis in 6 patients (mean 9%), and Prevotella intermedia (mean 2%) and other Prevotella species (mean 7%) in all patients. At 1 and 3 months after extraction, A. actinomycetemcomitans and P. gingivalis could not be detected in any of these patients on the oral mucous membranes and in saliva, while from all patients still P. intermedia (mean 3%) and the other blackpigmented Prevotella species (mean 4%) could be isolated. These results indicate that the preferable habitat for A. actinomycetemcomitans and P. gingivalis is dental plaque in subgingival lesions. P. intermedia and the other blackpigmented Prevotella species can colonize the oral mucous membranes of edentulous patients irrespective of the presence of a subgingival microflora. We speculate that in periodontal patients the colonization of mucous membranes with P. gingivalis and A. actinomycetemcomitans is transient in nature and most likely the result of dissemination from the subgingival microflora. Thus it seems unlikely that edentulous patients constitute a reservoir of infection of P. gingivalis A. actinomycetemcomitans.

Adolescent↗
PubMed1994

Experimental gingivitis during pregnancy and post-partum: clinical, endocrinological, and microbiological aspects.

The purpose of this study was to assess whether an intensive oral hygiene regimen practised during pregnancy results in a clinically healthy gingival state, and to assess whether experimentally-induced gingivitis differs in severity during pregnancy as compared to post-partum. In addition, levels of black-pigmented Gram negative anaerobes at subgingival and oral mucosal sites and plasma concentrations of free estrogens and prosterone were determined. These parameters were studied during a 14-day episode of experimental gingivitis induced in the 25th week of pregnancy, and again 6 months post-partum. The subjects were selected on shallow pockets < or = 4 mm and interproximal loss of attachment not exceeding 2 mm. As a result of controlled oral hygiene, the gingival condition improved both during pregnancy and post-partum. At day 0 during pregnancy, however, gingival swelling, redness, and bleeding on probing were found to be higher than post-partum. Free plasma levels of estrogens and progesterone were found to be normal throughout the study. It was hypothesized that the increase in severity of gingival symptoms during pregnancy reflect microvascular physiologic effects of increased levels of these hormones. During pregnancy, more swelling, redness and bleeding on probing developed during experimental gingivitis than post-partum, whereas the amount of plaque was similar in both phases. This suggests that as a result of dental plaque accumulation, gingival inflammation develops superimposed on pregnancy-associated physiologic alterations. Microbiological evaluation showed that the mean proportions of Prevotella intermedia in subgingival plaque increased during experimental gingivitis performed during pregnancy, whereas no increase of this micro-organism was found post-partum.

Adult↗
PubMed1994

Binding studies of a monoclonal antibody specific for 3-deoxy-D-manno-octulosonic acid with a panel of Klebsiella pneumoniae lipopolysaccharides representing all of the O serotypes.

A monoclonal antibody (MAb) raised against Salmonella minnesota R595 and specific for alpha-3-deoxy-D-manno-octulosonic acid (alpha-Kdo) of the inner core was tested for binding to lipopolysaccharides (LPS) of Klebsiella pneumoniae. The MAb was tested in several assay systems (enzyme-linked immunosorbent assay, passive hemolysis, and inhibition of passive hemolysis) with a large panel (n = 23) of K. pneumoniae LPS representing all nine currently known O serotypes. MAb 20 showed reactivity with almost all O serotypes of K. pneumoniae LPS, and this reactivity could be inhibited by synthetic Kdo. This suggests an epitope in the cores of these Klebsiella LPS much like that in the inner core of LPS of S. minnesota. Large differences in reactivity between LPS of different strains belonging to the same O serotype were observed. After sodium dodecyl sulfate-polyacrylamide gel electrophoresis of LPS followed by immunoblotting, reactivity of MAb 20 was observed only with the fast-moving fraction possibly representing the nonsubstituted core. No binding was seen with the high-molecular-weight fraction that contained core material substituted with several units of O-antigen building blocks. The chemical basis for these differences in reactivity remains to be established. As far as we know, this is the first report containing comprehensive immunochemical data on the LPS core of K. pneumoniae.

Antibodies, Monoclonal↗
PubMed1994

Lactoferrin is a lipid A-binding protein.

Lactoferrin (LF), a cationic 80-kDa protein present in polymorphonuclear leukocytes and in mucosal secretions, is known to have antibacterial effects on gram-negative bacteria, with a concomitant release of lipopolysaccharides (LPS, endotoxin). In addition, LF is known to decrease LPS-induced cytokine release by monocytes and LPS priming of polymorphonuclear leukocytes. Its mechanism of action is incompletely understood. We have now demonstrated by in vitro-binding studies that LF binds directly to isolated lipid A and intact LPS of clinically relevant serotypes of the species which most frequently cause bacteremia (Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa), as well as to lipid A and LPS of mucosal pathogens (among others, Neisseria meningitides and Haemophilus influenzae). Binding to LPS was inhibitable by lipid A and polymyxin B but not by KDO (3-deoxy-D-manno-octulosonate), a glycoside residue present in the inner core of LPS. Binding of LF to lipid A was saturable, and an affinity constant of 2 x 10(9) M-1 was calculated for the LF-lipid A interaction. Our data may explain, in part, the mechanism whereby LF exerts its antibacterial and anti-endotoxic effects. Further studies on the ability of LF to block the detrimental effects of LPS, both in vitro and in vivo, are warranted.

Carrier Proteins↗
PubMed1994

Recombinant human bactericidal/permeability-increasing protein (rBPI23) is a universal lipopolysaccharide-binding ligand.

A recombinant 23-kDa protein (rBPI23) derived from human bactericidal/permeability-increasing protein (BPI) possesses potent endotoxin-neutralizing abilities in vitro and in vivo. Binding of rBPI23 to those endotoxins (lipopolysaccharides [LPSs]) encountered clinically would be a prerequisite for efficacy in decreasing mortality among patients suffering from gram-negative sepsis and shock, a disease state in which an etiological role for LPS has been implicated. rBPI23 binds well to lipid A (n = 7), to rough-mutant O-chain-deficient LPS (n = 18, Re to Ra chemotypes), to lipid A-core covalently linked to the O chain, to LPSs from clinically relevant serotypes (n = 100), and to bacterial cells (n = 88) of Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae, the species most often implicated in clinical gram-negative sepsis and shock. Significant binding of rBPI23 to these antigens took place at rBPI23 concentrations of 1 to 500 ng/ml (median, 16 to 32 ng/ml). Binding did not involve 3-deoxy-D-manno-octulosonate of the inner core. Determining the exact epitope recognized by rBPI23 would require further studies with synthetic lipid A substructures. The demonstrated ability of rBPI23 to universally bind LPS provides a sound basis for further testing of its endotoxin-neutralizing abilities, including clinical trials.

Antibodies, Monoclonal↗
PubMed1994

Comparison of six typing methods for Actinobacillus actinomycetemcomitans.

Actinobacillus actinomycetemcomitans is an important pathogen in the etiology of severe periodontitis. For epidemiological studies on the prevalence of certain pathogenic clones and transmission of this bacterium, adequate typing methods are necessary. The purpose of this study was to compare six different typing methods for A. actinomycetemcomitans. Five reference strains and 27 fresh clinical isolates from periodontitis patients were used. Serotyping showed 12 serotype a strains, 13 type b strains, 6 type c strains, and 1 nontypeable strain. Biotyping on the basis of the fermentation of mannose, mannitol, and xylose resulted in six biotypes. Antibiogram typing was evaluated by measuring the inhibition zones of seven antibiotics in agar diffusion tests. With this method eight main types which could be further differentiated into 15 subtypes were found. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns of outer membrane proteins were similar among all isolates tested. Restriction endonuclease analysis (REA) of whole chromosomal DNA resulted in five main types. These five main types were further differentiated into 24 subtypes on the basis of DNA fragment differences in the high-molecular-weight region. Hybridization of DNA fragments with ribosomal DNA (ribotyping) resulted in 22 to 24 different types, depending on the restriction endonuclease used. Ribotype patterns were easy to interpret and provided an univocal distinction between different strains compared with REA results. When applied to epidemiologically related isolates, all methods were able to discriminate two clonal types among five isolates from five children from one family. We conclude that serotyping, biotyping, and outer membrane patterns were reproducible but had a low discriminatory potential. REA and ribotyping were reproducible and gave the highest number of distinct types. When the DNA typing methodis were compared, all strains tested could be distinguished. These findings confirm the heterogeneity found within the species A. actinomycetemcomitans.

Aggregatibacter actinomycetemcomitans↗
PubMed1994

Importance of the fiberoptic endoscope cleaning procedure for detection of Helicobacter pylori in gastric biopsy specimens by PCR.

A 16S ribosomal DNA-based PCR appeared to be a sensitive test for the detection of infection by Helicobacter pylori in 31 patients when compared with culturing and histological and serological techniques. For five patients, PCR was the only test with a positive result. H. pylori DNA was also found in gastrointestinal equipment even after standard intensive combined manual and machine cleaning. We therefore conclude that a reliable validation of PCR for the detection of H. pylori in gastric biopsy specimens is possible only when the cleaning and disinfection method used has been proven to remove all H. pylori DNA from gastrointestinal equipment. An adequate cleaning and disinfection method for the removal of H. pylori DNA from fiberoptic endoscopes is described.

Base Sequence↗
PubMed1994

Bacterial colonization and degradation of demineralized dentin matrix in situ.

Lesion formation in dentin involves demineralization followed by degradation of the exposed organic matrix. Proteinases from microorganisms present in the dentin are believed to play an important role in the breakdown of the dentinal collagen. In this study, the microflora colonizing decalcified dentin matrix, placed in situ, was identified. The gelatinolytic activity of the isolated strains was assessed and related to the degradation of the dentin matrix. The predominant species found were Streptococcus mitis. Peptostreptococcus productus, Lactobacillus casei, Propionibacterium species and Veillonella parvula. Marked interindividual variation in the composition of the microflora was observed. The microflora possessed gelatinolytic activity, although no correlation was found with the severity of dentin matrix degradation. The chemically determined loss of collagen varied between 0 and 67 wt% per participant and corresponded with the extent of collagen degradation observed by transmission electron microscopy.

Animals↗
PubMed1994

[HIV and dentistry. Part 2. Needlestick injury].

The risk for dentists to acquire HIV infection at work is low but not neglectable. Needlestick injuries are among the most hazardous events in this respect. Prevention of these injuries will considerably reduce the risk of occupational HIV infection in dentistry.

HIV Infections↗
PubMed1994

[Symptomatic bacteremia after periodontal treatment].

Symptomatic bacteremia after dental treatment in an apparently healthy patient is an indication for preventive antibiotic treatment. This article describes the case of a patient with clinical symptoms of bacteremia after periodontal treatment, in whom the blood cultures remained positive after oral administration of amoxicillin (Chlamoxyl). Intramuscular administration of penicillin (Bicilline) was able to prevent the clinical symptoms as well as the bacteremia.

Administration, Oral↗
PubMed1993

Adherence of Streptococcus gordonii HG 222 in the presence of saliva.

The influence of the presence of saliva from different salivary glands on the adherence of Streptococcus gordonii strain HG 222 to saliva-coated polystyrene surfaces was tested. In the presence of undiluted parotid saliva or diluted whole, submandibular and sublingual saliva the adherence of HG 222 was enhanced by the formation of small aggregates on the attachment surface. In the presence of undiluted whole, submandibular and sublingual saliva large aggregates were formed and the adherence to saliva-coated polystyrene surfaces was inhibited. Adherence in the presence of whole saliva compared to adherence in buffer was decreased when lower densities of bacterial suspension were used, although in this case in the presence of whole saliva smaller bacterial aggregates were formed. In conclusion, these results suggest that the presence of saliva in solution may both enhance and decrease the adherence of S. gordonii HG 222 to saliva-coated polystyrene surfaces, partly depending on the size of bacterial aggregates that are formed in the presence of saliva.

Adult↗
PubMed1993

Long-standing bacteremia caused by oral Actinobacillus actinomycetemcomitans in a patient with a pacemaker.

A case of symptomatic Actinobacillus actinomycetemcomitans bacteremia in a patient with an implanted pacemaker is presented. Attacks of fever occurred for at least 1 year. Oral examination revealed a mild form of periodontitis. A. actinomycetemcomitans was isolated from several oral sites. DNA fingerprinting of strains from the blood and the oral cavity showed identical profiles. This finding strongly suggests that the oral cavity was the primary source of A. actinomycetemcomitans bacteremia in this case. The patient was treated with the combination of metronidazole plus amoxicillin for 7 days, which resulted in a rapid cure and elimination of A. actinomycetemcomitans from the blood and the oral cavity.

Actinobacillus Infections↗
PubMed1993

Description of two morphotypes of Peptostreptococcus micros.

Peptostreptococcus micros is often isolated from abscesses in several parts of the human body. The oral cavity is considered the natural habitat for the species, which has been implicated as a periodontal pathogen. In plaque samples from periodontitis patients we observed the presence of a rough morphotype of P. micros in addition to the previously recognized smooth morphotype. The rough morphotype has not been described previously. Both morphotypes are frequently isolated simultaneously from the same patient. In this paper strains of both morphotypes are described. The smooth morphotype, represented by the type strain, grew as small, dome-shaped, bright white, nonhemolytic colonies. The rough morphotype grew as equally white dry colonies which were hemolytic and had wrinkled edges. DNA-DNA reassociation studies revealed homology at the species level between the two morphotypes; in addition, no differences in physiological characteristics were observed when the organisms were tested with API-32A and API-ZYM kits. The rough cells had long, thin fibrillar structures outside the cell envelope when they were stained negatively for electron microscopy. In the smooth morphotype these structures were not present. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles of whole-cell extracts were different for the two morphotypes. In xylene-water phase partition studies, the smooth morphotype was found to be hydrophobic, whereas the rough morphotype was found to be relatively hydrophilic. The distinct morphotypes were stable on blood agar; however, the rough morphotype changed to a nonfibrillar type with a smooth colony morphology after repeated subculturing in broth.

Animals↗
PubMed1993

Migration of rat peritoneal cells after intra-abdominal infection with Bacteroides fragilis and Escherichia coli.

A fibrin clot model for intra-abdominal abscess formation was used to study the migratory properties of peritoneal cells from rats during the early stages of infection. Peritoneal cells and fibrin clot remnant were harvested 6 h after implantation of a sterile, singly infected (Escherichia coli or Bacteroides fragilis) or mixed infected (E. coli and B. fragilis) fibrin clot. Histological study of fibrin clots, removed 6 h after implantation, showed a deeper infiltration by host cells of B. fragilis infected clots compared to the others. This difference in infiltration by peritoneal cells was not due to differences in fibrinolytic activity of the bacterial strains. Differential cell counts of the peritoneal cells from rats implanted with sterile, singly and mixed infected fibrin clots showed distribution over subpopulations to be independent of the bacterial content of the infected clots used. In vitro migration assays showed no significant differences in migration by peritoneal cells from rats implanted with clots containing a different bacterial composition. Since B. fragilis infected fibrin clots were more deeply infiltrated by host defence cells than the other clots, and only mixed infected clots led to persistent abscesses in this model, we conclude that local conditions within the fibrin matrix rather than intrinsic cellular capacities of the host cells are important for the process of abscess formation.

Animals↗
PubMed1993

Porphyromonas endodontalis: prevalence and distribution of restriction enzyme patterns in families.

In this study we determined the prevalence and distribution of Porphyromonas endodontalis in 26 families consisting of 107 subjects. P. endodontalis was present in 24% of the investigated subjects and was recovered most often from the dorsum of the tongue (50%). Isolation was also possible from the tonsils, the buccal mucosa, the saliva and the periodontal pocket. The usefulness of restriction endonuclease analysis as a typing method for this particular species was investigated by typing 19 isolates from unrelated individuals. All these isolates had unique restriction endonuclease patterns. The observed heterogeneity indicates that restriction endonuclease analysis is a sensitive measure of genetic dissimilarity between P. endodontalis isolates and is able to characterize individual isolates. Application of restriction endonuclease analysis to the obtained clinical isolates in this study shows the possibility of the presence of multiple clonal types within one subject. The DNA patterns of all P. endodontalis isolates from unrelated individuals were found to be distinct. In 3 families the DNA patterns of isolates from the mother and her child were indistinguishable. These data indicate the possibility of intrafamilial transmission of P. endodontalis.

Adolescent↗