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Biomedical subjects

J O Berg

Publications and source records attributed to J O Berg.

17 recordsLinked to original sources
PubMed1990

Cellular reactions in pulpal and periodontal tissues after periodontal wound debridement.

Periodontal wounds in monkeys were prepared with a bur followed by the application of microbially contaminated cotton pellets. 3 weeks later, the wounds were debrided by scaling followed by etching with citric acid or by treatment with carbonate/peroxidate. The cellular reactions in the periodontal tissues and in the pulp 4, 11, 25, 39 and 53 days after treatment were followed with light microscopy. The marginal periodontium showed heavy inflammatory reactions immediately after treatment, regardless of the debridement procedure. 25 days after debridement, a long epithelial junction had been formed. The apical part of the epithelium deviated from the root surface into the connective tissue, delineating a heavily inflamed part of the connective tissue. After 39 to 53 days, most of the experimental wounds were covered by an epithelial lining. The pulpal reactions were generally limited to a production of irregular dentin on the pulpal wall facing the periodontal wound. It was concluded that the marginal healing pattern following various chemical treatments to the root surface followed, in all essential aspects, conventional treatment with scaling and root planing.

Animals↗
PubMed1987

Blood flow changes in the dental pulp of the cat and rat measured simultaneously by laser Doppler flowmetry and local 125I clearance.

Blood flow changes in the dental pulp of lower canine teeth of mature cats and incisors of mature rats were investigated with simultaneous laser Doppler flowmetry and local 125I-clearance (wash-out) during electrical sympathetic stimulation, efferent stimulation of n. alveolaris inferior (IAN) (cats) and i.a. infusions of substance P (SP) (cats). Stimulation (1-4 Hz, 4 V., 1.5 ms) of the cervical sympathetic trunk produced frequency-dependent decreases in both laser Doppler output and disappearance rate of iodine tracer from the dental pulp. For the effects of sympathetic stimulation, the correlation (r2) between the results obtained by the two methods was 0.89 (12 observations, six animals). Blood flow measurements by both methods were increased following i.a. infusions of SP (r2 = 0.64, six observations, three animals). However, upon stimulation of IAN (10 Hz 10 V, 5 ms) the laser Doppler flow values showed an increase while the local 125I clearance rate was unaffected or even decreased. The discrepancy between the results obtained following IAN stimulation indicates that the two methods reflect blood flow changes in different parts of the pulpal vascular bed and that the flow is unevenly distributed to these parts during antidromic IAN stimulation. The laser Doppler flowmetry seems to reflect the total blood flow in the coronal pulp and therefore this non-invasive method may be useful for monitoring blood flow changes in the tooth.

Animals↗
PubMed1987

Acute changes in intra-alveolar tooth position and local clearance of 125I from the periodontal ligament.

Changes in intra-alveolar tooth position and local 125I clearance from the periodontal ligament (PDL) were monitored simultaneously in cats. Axial tooth movements, reflecting periodontal ligament volume changes, were measured with an ultrasonic transit time technique. Local blood flow changes in the PDL were studied indirectly by measuring the local clearance of 125I-. Stimulation of the cervical sympathetic trunk caused an intrusive movement of the tooth with a concomitant reduction of the 125I- clearance. Infusion of noradrenaline induced a similar response. Stimulation of the inferior alveolar nerve during systemic treatment with phentolamine caused an extrusive movement of the tooth with a concomitant increase in the clearance of the tracer from the PDL. Intra-arterial infusion of the vasodilator substance P mimicked that response. Fixation of the tooth to the jaw bone, thus preventing an intrusive movement, did not change the reductions in clearance seen on sympathetic stimulation, indicating that this blood flow reduction was not dependent on tooth movement. A qualitative relation between PDL blood flow (as measured by local 125I clearance) and PDL volume (as measured by tooth position) is shown. The two variables measured are suggested to reflect two aspects of blood flow in the PDL.

Alveolar Process↗
PubMed1983

Neuraminidase in Bacteroides fragilis.

A neuraminidase from Bacteroides fragilis was purified 542-fold by isoelectric focusing, adsorption chromatography on Affi-Gel 202, and gel filtration chromatography on Sephadex G-200. On isoelectric focusing the neuraminidase was resolved into three differently charged fractions with pI values of 6.8, 7.1, and 7.4. The major component of pI 7.1 was used for further purification. The purified enzyme had optimal activity at pH 6.4 with N-acetylneuraminlactose as the substrate. Its molecular weight, determined by Sephadex G-200 gel filtration chromatography, was 92,000. The neuraminidase hydrolyzed terminal neuraminic acid residues from N-acetylneuraminlactose, fetuin, bovine submaxillary mucin, and porcine stomach lining mucin. A new method for the detection of neuraminidase activity is described which is based on rocket affinoelectrophoresis. It utilizes the differences in the interaction of sialylated and desialylated mucin with Helix pomatia lectin, enzymatic activity being detected by formation of affinorockets after incubation of the neuraminidase with bovine submaxillary mucin.

Bacteroides fragilis↗
PubMed1980

In vivo and in vitro studies of inhibitory effects of restorative dental materials on salivary esterases.

The influence of 18 dental materials on the activity of esterases isolated from human whole saliva has been studied. Eugenol on its own was a strong competitive inhibitor of the esterases II-2a (Ki = 3.3/10(-5) M) and II-2b (Ki = 4.7/10(-6) M). Except for Luralite all the materials that contained eugenol as one of the components (IRM, Nobetec and Opotow) were noncompetitive inhibitors. Additional in vitro inhibitors were: Adaptic, Aspa, Coe-pack and the amalgam ANA 68. Treatment with Nobetec packs in vivo resulted in a decrease activity of whole saliva.

Dental Materials↗
PubMed1980

Purification of glycoside hydrolases from Bacteroides fragilis.

Six glycoside hydrolases in the culture medium of Bacteroides fragilis--alpha-glucosidase, beta-glucosidase, alpha-galactosidase, beta-galactosidase, beta-N-acetylglucosaminidase, and alpha-L-fucosidase-were systematically purified by ammonium sulfate precipitation, gel filtration chromatography, and density gradient isoelectric focusing. The isoelectric focusing resolved the glycosidases into distinct, well-separated fractions and revealed three differently charged forms of beta-N-acetylglucosaminidase and of alpha-L-fucosidase. Furthermore, alpha-glucosidase and beta-N-acetylglucosaminidase were shown to possess dual affinities for the respective galactoside substrates, and beta-galactosidase also hydrolyzed beta-D-fucoside. alpha-Glucosidase was purified to homogeneity, as indicated by a thin-layer isoelectric focusing zymogram technique. The glycosidases, with exception of beta-glucosidase and the acid alpha-L-fucosidase, were each separated from other glycosidic activities to 99%. The molecular weights varied between 58,000 and 125,000. The pH optima ranged from 4.8 to 6.9.

Acetylglucosaminidase↗
PubMed1978

Formation of glycosidases in batch and continuous culture of Bacteroides fragilis.

Nine strains of bacteroides fragilis were cultivated in stirred fermentors and tested for their ability to produce glycosidases. B. fragilis subsp. vulgatus B70 was used for optimizing the production of glycosidases. The highest bacterial yield was obtained in proteose peptone-yeast extract medium. The optimum pH for maximal bacterial yield was 7.0, and the optimum temperature for growth was 37 degrees C. The formation of glycosidases was optimal between pH 6.5 and 7.5, and the optimum temperature for synthesis of glycosidases was between 33 and 37 degrees C. Culture under controlled conditions in fermentors gave more reproducible production of glycosidases than static cultures in bottles. The strain was also grown in continuous culture at a dilution rate of 0.1 liter/h at pH 7.0 and 37 degrees C with a yield of 2.0 mg of dry weight per ml in the complex medium. The formation of glycosidases remained constant during the entire continuous process.

Bacteriological Techniques↗
PubMedDate not supplied

[Calcitonin as an alternative treatment for root resorption].

Inflammatory root resorption is a common finding following trauma and will cause eventual destruction of the tooth root if left untreated. This study examined the effects of intrapulpal application of calcitonin, a hormone known to inhibit osteoclastic bone resorption, on experimental inflammatory root resorption induced in monkeys. Results were histologically evaluated using a morphometric technique and revealed that calcitonin was an effective medicament for the treatment of inflammatory root resorption. It was concluded that this hormone could be a useful therapeutic adjunct in difficult cases of external root resorption.

Animals↗