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Biomedical subjects

J de Graaff

Publications and source records attributed to J de Graaff.

At least 127 records · Page 7Linked to original sources
PubMed1986

Serological characterization of black-pigmented Bacteroides endodontalis.

Serological studies on the black-pigmented Bacteroides species B. endodontalis revealed three serotypes based on capsular determinants. A common antigen (O-antigen) could be demonstrated after decapsulation. Weak cross-reactivity was found with B. asaccharolyticus, but not with B. gingivalis. Similarity between the serology of Enterobacteriaceae and black-pigmented Bacteroides spp. is discussed.

Agglutinins↗
PubMed1986

Comparison of two selective media for Actinobacillus actinomycetemcomitans.

Two selective media, malachite green-bacitracin (MGB) agar and tryptic soy-serum-bacitracin-vancomycin (TSBV) agar, were compared for the isolation of Actinobacillus actinomycetemcomitans. The highest recovery was found on TSBV agar plates cultured in air-5% CO2 both for plaque samples from periodontal pockets and for pure cultures.

Actinobacillus↗
PubMed1986

Effects of ammonia and volatile fatty acids produced by oral bacteria on tissue culture cells.

Culture filtrates of several bacterial species isolated from the oral cavity were tested for their effects on two types of tissue culture cells: Vero cells, the continuous cell line of African green monkey kidney cells; and chondrocytes, isolated from 15-day-old chick embryo tibiae. Only a limited number of bacterial species--i.e., the asaccharolytic black-pigmented Bacteroides species and Fusobacterium species--affected the two cell types. The effect on Vero cells, detected by the rounding of the cells, correlated with the butyric acid concentration in the bacterial supernatant, which confirms previous findings. A small enhancement of this effect was found with propionic acid and ammonium ions. The same strains which affected Vero cells also affected chondrocytes, detected by a vacuolization of the cells. However, volatile fatty acids on their own had no visible effect on these cells. Instead, ammonium ion in the culture filtrate, when present in concentrations of 20 to 60 mmol/L, proved to be responsible for vacuolization of the chondrocytes. The volatile fatty acids (butyric and propionic) had a limited additive effect. No effects were visible with cell extracts of the bacteria.

Actinomyces↗
PubMed1985

Peripartal cardiomyopathy.

A case of peripartal cardiomyopathy diagnosed post partum by preoperative routine examination for a sterilization operation is discussed. Data from the literature show that 50% of the patients suffering from peripartal cardiomyopathy recover nearly completely; the other patients with distinct symptoms of cardial insufficiency die almost without exception from the disease. Current concepts of diagnosis and treatment are reviewed.

Adult↗
PubMed1985

Histopathological changes in the hind foot of the mouse induced by black-pigmented Bacteroides strains.

The pathogenic potential of black-pigmented Bacteroides strains was studied in an animal model in which the effect on bone tissue could be determined. Bacteria suspended in agar were injected subcutaneously in the left hind paw of a mouse. After 3-5 days, B. gingivalis strain HG 66 had caused a massive infiltration with polymorphonuclear cells, destruction of the periosteum on the metatarsals and bone resorption by osteoclasts. After 7 days only a few osteoclasts remained and reactive bone formation was observed. In a comparative study with strains of several black-pigmented Bacteroides species, differences in bone resorbing potential were seen. B. gingivalis strains caused severe inflammation which resulted in bone resorption. Strains of B. asaccharolyticus, B. endodontalis, B. intermedius, B. melaninogenicus and B. loeschei caused less inflammation and less bone resorption. Killed bacteria or agar alone caused a relatively mild inflammation and no bone resorption.

Animals↗
PubMed1985

Bacteroides endodontalis and other black-pigmented Bacteroides species in odontogenic abscesses.

Twenty-eight odontogenic abscesses were examined for the presence of black-pigmented Bacteroides spp. Of the 28 samples, 26 were found to contain one or more species of black-pigmented Bacteroides. Abscesses were divided into three categories according to the tissue of origin: endodontal, periodontal, and pericoronal. Four abscesses which developed after extraction were also examined. It was found that Bacteroides endodontalis, a newly described species of asaccharolytic black-pigmented Bacteroides, was isolated almost exclusively from periapical abscesses of endodontal origin. B. intermedius proved to be the most frequently isolated species in all of the samples. B. gingivalis was present in all of the periodontal abscesses studied, as well as in two endodontal abscesses. B. melaninogenicus was recovered once from a pericoronal abscess. Precautions for the isolation of B. endodontalis are discussed.

Adolescent↗
PubMed1984

Pathogenic synergy: mixed infections in the oral cavity.

In almost all infections in the oral cavity, mixed populations of bacteria are present. However, recent evidence points to a certain specificity in these infections: Streptococcus mutans is related to caries and black-pigmented Bacteroides species are suspected pathogens in periodontal disease. Periodontal diseases, endodontic infections and submucous abscesses in the oral cavity are probably mixed infections in which anaerobic bacteria together with facultatives or other anaerobes are present. In experimental mixed anaerobic infections black-pigmented Bacteroides strains have been shown to play a key role. Little is known about the pathogenic synergy between the bacteria involved in mixed infections. Important mechanisms could be nutritional interrelationships and interactions with the host defense. Within the group of black-pigmented Bacteroides B. gingivalis seems to be the most virulent species. These bacteria possess a great number of virulence factors, which might be important in the pathogenesis of oral infections.

Actinomyces↗
PubMed1984

Efficacy of 2.5% Pimafucin suspension in the treatment of denture stomatitis.

This double-blind clinical trial was carried out in 38 patients to compare the efficacy of 2.5% Pimafucin suspension with a placebo in the treatment of denture stomatitis. The diagnosis of Candida infection was confirmed by the making of cultures and microscopic examination. Data were analyzed from 32 patients, of whom 18 received Pimafucin suspension and 14 a placebo suspension. Pimafucin suspension-treated patients showed a significant reduction of Candida infection in terms of culture, culture growth, and number of colonies within the first week of therapy. There was no statistical evidence of relapse during the 4-week period after therapy was stopped. The group receiving a placebo failed to show any statistically significant improvement with respect to the mentioned parameters. Erythema of oral mucosa showed significant improvement in both groups. No side effects were found.

Adult↗
PubMed1983

Virulence of beta-hemolytic and non-hemolytic Streptococcus mutans: lethal dose determinations in neonatal mice.

The virulence of beta-hemolytic and non-hemolytic strains of Streptococcus mutans was studied in neonatal mice by LD50 determinations after intracerebral injection of the bacteria. Although the differences in LD50 values are small the results may indicate that beta-hemolytic S. mutans strains (mean LD50 of 6.3 X 10(7) c.f.u.) were more virulent than non-hemolytic S. mutans strains (mean LD50 of 47.7 X 10(7) c.f.u.). The LD50 values of other viridans streptococci varied between 4.8 and 10(7) c.f.u. Strains of S. pyogenes and S. agalactiae were highly virulent in this animal model with LD50 values lower than 10(5) c.f.u.

Animals↗
PubMed1983

Inactivation of haemolysin production in Escherichia coli by transposon insertion results in loss of virulence.

A haemolytic E. coli strain is nephropathogenic for mice. Mutagenesis by transposon insertion resulted in mutants with altered haemolytic activity. Reduction or elimination of the haemolytic activity is accompanied with loss of virulence. It is shown that this loss of virulence is due to altered haemolytic activity and not caused by the transposon insertion itself.

DNA Transposable Elements↗