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Biomedical subjects

J Westergaard

Publications and source records attributed to J Westergaard.

17 recordsLinked to original sources
PubMed1991

Organic content in occlusal groove-fossa-system in unerupted 3rd mandibular molars: a light and electron microscopic study.

A method is described by means of which organic content in fissure areas of 12 unerupted 3rd mandibular molars can be prepared for studies in the light microscope (LM) and in the transmission electron microscope (TEM). Thus, LM and TEM examinations revealed that the organic content throughout the fissure in bone-covered and in mucosa-covered 3rd molars with uncompleted root formation consists of cells belonging to the enamel organ in late or in postmaturative stages. In mucosa-covered teeth with completed root formation it was only possible to identify enamel organ cells at the entrance of the fissure. Deeper parts were occupied by degenerative cells, polymorphonuclear cells and unidentified material. The results indicate that ameloblasts in fissures do not transform to stratified squamous epithelium but gradually degenerate towards terminal stages and remain as such, as the tooth emerges into the oral cavity.

Adolescent↗
PubMed1990

Effect of dental plaque control on gingival lichen planus.

Eleven patients, all women, aged 43 to 76 years, with atrophic or ulcerative lichen planus lesions of gingiva were included in this preliminary study. After initial examination, the patients received an intensive individual hygiene treatment. The patients continued using the most appropriate, atraumatic method resulting in the best possible oral hygiene over a 1 year period during which they were seen for follow-up examinations at 3-month intervals. The mean plaque scores decreased after the initial treatment followed by an increase. The mean scores for severity of subjective symptoms and for type and extension of lesions initially decreased with the plaque scores and remained lower throughout the study. It is concluded that in some cases both subjective and objective improvement of atrophic and ulcerative gingival lichen planus may be obtained by means of intensive oral hygiene procedures although such procedures do not remove the basic cause of lichen planus. However, further studies are needed to examine the role of dental plaque control in patients with oral lichen planus.

Adult↗
PubMed1990

Doxycycline-resistant bacteria in periodontally diseased individuals after systemic doxycycline therapy and in healthy individuals.

The occurrence of doxycycline-resistant bacteria was examined in subgingival plaque and on the tonsils of 12 periodontally healthy and 12 periodontally diseased individuals. The healthy group was examined 6 times at intervals of one month. The diseased group was examined before and 1, 5, 15, 26, 39, and 52 weeks after conventional periodontal therapy supplemented with systemic doxycycline for 3 weeks. The occurrence of doxycycline-resistant bacteria in the healthy group varied on average between 2.0% and 6.6% in subgingival plaque and between 3.0% and 12.4% in the tonsil samples over a 6-month period. In the diseased group the percentage of resistant bacteria increased from 10-20 times for tonsil and subgingival plaque, respectively. About half a year after therapy the values returned to the baselines. For both groups the morphological distributions of resistant bacteria were similar and unaffected by the doxycycline therapy.

Adult↗
PubMed1990

Microbial patterns in pooled subgingival plaque samples from young adults with advanced marginal periodontitis.

Different bacterial profiles of subgingival plaque have been described for different clinical categories of marginal periodontitis. In the present investigation the subgingival microflora was studied in young adults with advanced marginal periodontitis. From 12 patients pooled subgingival plaque samples from 5 advanced stages of diseased sites were examined by direct differential phase-contrast microscopy and by cultivation on enriched and selective media. The proportions of the following genera and species were calculated: black-pigmented Bacteroides sp., B. gingivalis, Fusobacterium nucleatum, Veillonella sp., Actinobacillus actinomycetemcomitans, Capnocytophaga sp., Eikenella corrodens, Campylobacter sp., and Candida sp. Spirochete identification was carried out ultrastructurally. Calculated percent minimum similarity levels between the individuals revealed that each patient harbored its characteristic cultivable subgingival microflora different from the other individuals. The spirochetes seemed to constitute the subgingival bacterial group with the smallest variation as certain morphotypes were dominating in almost all individuals.

Adult↗
PubMed1987

Morphological distribution of spirochetes in subgingival plaque from advanced marginal periodontitis in humans.

The purpose of this study was to elucidate the distribution of spirochetes (SP), on the basis of ultrastructural criteria in subgingival plaque from patients with advanced marginal periodontitis. Samples were obtained by a paperpoint technique from 18 pockets 6-10 mm in depth from 12 individuals. On grids with negatively stained material, more than 50 SP were photographed from each sample. The SP were primarily grouped according to the number of endoflagella from each cell-end, with the exception of SP with more than eight endoflagella, which were pooled in one group. The diameter, the length, the wavelength and the amplitude of the SP were measured and related to the number of the endoflagella. The 95 per cent and 99 per cent confidence intervals were estimated. Owing to the number of endoflagella, the distribution of SP varied in the separate samples and no relationship to pocket depth was found. SP containing two endoflagella were the pre-dominating type. On the basis of the dimensions of the diameter, the length, the wavelength and the amplitude, the SP fell into four significantly different morphological groups characterized by 1, 2, 3-8, and more than 8 endoflagella, as the values in general increased from group to group.

Dental Plaque↗
PubMed1986

Nutrient and environmental growth factors for eight small-sized oral spirochetes.

The present investigation was carried out in order to obtain better information about the growth requirements for small-sized oral spirochetes containing two endoflagella from each cell-end. Eight strains of such spirochetes were isolated from subgingival plaque in patients suffering from advanced marginal periodontitis. The strains were maintained under anaerobic conditions in a fluid basal BHI medium with 15% inactivated rabbit serum, 0.07% Noble Agar and 5 micrograms/ml cocarboxylase. Firstly, the effect of trace amounts of oxygen in the atmosphere and pH in the medium on growth of the spirochete strains were examined. Secondly, the effect of different sera incorporated in the medium was examined, and thirdly, the effect of important growth factors in serum was studied by adding different serum components to the fluid basal medium instead of rabbit serum. Growth was always determined after 4 days' incubation at 35 degrees C, either by counting numbers of spirochete cells in a Petroff-Hauser counting chamber or by measuring the turbidity of the culture spectrophotometrically at 600 nm. There was no difference in growth by using an atmosphere containing 1% oxygen or an anaerobic atmosphere. It was found that serum (rabbit or human) was an essential growth component, and no single growth factor could replace rabbit serum. Only a long chain fatty acid mixture and an amino acid solution could, to a minor extent, stimulate growth compared to the basal medium without rabbit serum. Sodium bicarbonate inhibited growth of all strains. Finally, none of the strains fermented a series of low molecular weight carbohydrates, but all strains produced H2S and indole.

Bicarbonates↗
PubMed1978

An automatic multi-programmed affinity chromatographic system.

An automatic immunospecific affinity-chromatographic system for continuous operation is described. The system comprises time-controlled sample application, washing and elution steps and automatic dialysis of eluted fractions. The applicability of the system is illustrated by the purification of pregnancy zone protein on immunosorbent gel.

Blood Proteins↗
PubMed1978

Ultrastructure of the subgingival microflora in juvenile periodontitis.

The ultrastructure of the subgingival deposits on the root surfaces of teeth affected by juvenile periodontitis was studied on 12 teeth from nine individuals, 15--30 years of age. The deposits consisted of either microbial masses associated with a pellicle, or of a cuticular material almost free of bacteria. Gram-negative rods and filaments were the predominant microorganisms. "Corncob" configurations consisting of filamentous bacteria surrounded by Gram-positive cocci, and "bristle brush" formations comprising corncobs surrounded by long rods were observed in the superficial layer of the plaque. Spirochetes and flagellated rods constituted a major segment of the microflora. The present data indicated that the deep pockets in juvenile periodontitis harbor a sparse but relatively characteristic microbial population.

Adolescent↗
PubMed1976

Termination of pregnancy in cases of fetal death in utero by intravenous prostaglandin F2alpha.

Delivery was induced by an intravenous infusion of prostaglandin F2alpha (PGF2alpha) in gradually increasing doses in 30 consecutive cases of fetal death in utero after the 28th week of gestation. Twenty patients delivered during the first day of prostaglandin administration, 9 on the second day, and 1 patient not until the third day of infusion. It is concluded, that intravenous PGF2alpha appears to be superior to oxytocin in termination of pregnancy under these conditions.

Abortion, Induced↗
PubMed1975

Dose and age dependent variations in effect of tetracycline on enamel formation in rat.

Incidence of rats with gross enamel lesions in response to tetracycline hydrochloride (TC) was studied in relationship to age, tooth type, and concentration of antibiotic in the injection fluid. Incidence was defined as percentage of animals with defects in at least one incisor or one molar. Serum levels were measured at various intervals in 4- and 75-day-old rats, which received a single i.p. injection with 130 mg/kg bw in concentrations of either 13 or 25 mg/ml saline. The study confirmed that the effect of TC on enamel varied with age of the animal and that the molar responded more readily than the incisor. Furthermore, the incidence was higher the higher the concentration of antibiotic. This effect appeared tied to a direct relationship between concentration and serum level. Serum levels declined more slowly in the younger than in the older rats, resulting in significantly higher levels 6, 24 and 48 h after dosing, which correlated with a more extensive labeling of the dentin in the young rats. The possible roles of serum levels, capillary supply and cell susceptibility are discussed in relation to differences in response with animal age, between tooth types, tooth surfaces and with age of the secretory cells.

Age Factors↗