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Biomedical subjects

I Olsen

Publications and source records attributed to I Olsen.

261 records · Page 15Linked to original sources
PubMedDate not supplied

Effects of therapeutic ultrasound on osteoblast gene expression.

Ultrasound (US) is commonly used as a physiotherapy aid for a number of types of injury to soft connective tissues and for fracture healing. However, the precise effects of therapeutic US on tissue healing processes are not clearly understood, although they are likely to involve changes in key cellular functions. The present study has therefore examined the effects of several US intensity levels on the activity of two bone-associated proteins, alkaline phosphatase (ALP) and osteopontin (OP) in a human cell line, MG63, using RT-PCR. ALP showed progressively higher expression with increasing US intensities, whereas OP responded differently, showing down-regulation at 120 mW/cm2, the lowest US exposure. OP expression was considerably less affected overall compared with the relative response of ALP to the same US doses. The results show that there is a differential response to therapeutic levels of US, since ALP and OP clearly exhibited gene-specific response profiles. These findings suggest that modifying the parameters of US exposure could be used to improve repair and regeneration processes and enhance the clinical efficacy of implanted biomaterials for tissue engineering.

Journal Article↗
PubMedDate not supplied

Direct enzyme transfer from lymphocytes is specific.

Lymphocytes are known to interact directly with other cells in vivo and in vitro, and have recently been shown to transfer the lysosomal enzyme, beta-glucuronidase, to fibroblasts from patients with an inherited deficiency of the enzyme. This process requires cell-cell contact, is unaffected by inhibitors of 'classical' receptor-mediated endocytosis and is abolished by inhibitors of protein synthesis. Although it is not yet known to what extent the transfer of enzymes by direct cellular interaction is a general phenomenon, a similar mechanism could possibly be involved in the transfer of other lysosomal enzymes in vivo and in the exchange of protein in vitro. We show here that the direct transfer of enzymes from lymphocytes to fibroblasts is restricted to only certain lysosomal enzymes.

Animals↗
PubMedDate not supplied

Denture stomatitis-yeast occurrence and the pH of saliva and denture plaque.

The study comprised 30 denture wearers with generalized simple or granular inflammation in the palate and 30 without (controls). )easts, mostly Candida species, were cultivated from the maxillary dentures of all subjects with inflammation and of 23 controls. Hyphae were found in the maxillary denture smears from 28 subjects with inflammation and from 18 controls. Thus it seems unjustified to consider the occurrence of hyphae pathognomonic of denture stomatitis. The pH of whole saliva did not differ in the two groups (inflammation:mean pH 6.5, control:6.6). There was no clear relation between the pH of resting saliva and the amount of fungal cultures. Thirty minutes after a mouthrinse with 10 ml of a 25% sucrose solution, the mean saliva pH had dropped equally in both groups. With regard to the denture plaque, samples taken 40 min after the rinse indicated a more pronounced acid production in the plaque associated with inflammation. The pH of "resting" plaque was also lower in the inflammation than in the control group (mean maxillary pH 5.7 and 6.3 respectively, a=0.002). No association was found between the pH and the occurrence of hyphae in "resting" denture plaque. This supports the view that the pH is of no major importance for filamentation in vivo.

Adult↗
PubMedDate not supplied

Experimental palatal candidosis and saliva flow in monkeys.

Maxillary acrylic plates, inoculated with Candida albicans, were inserted for 3 weeks in 10 monkeys (Cercopithecus aethiops) (Series I), and reinserted in five of the animals 8 weeks after removal (Series II). To suppress saliva flow oxyphencyclimine was injected intramuscularly (0.125 mg/kg) thrice daily for 3 weeks in six monkeys of Series I, while four controls received no drug. In Series II the oxyphencyclimine dose was doubled in three animals, and two controls were sham-treated with sodium chloride. Mean saliva flow was reduced to 58% after 1 week and to 63% after 3 weeks with the low dose of oxyphencyclimine. The values with the high dose were 56% and 64%, respectively. After 1 week thrush had developed beneath the plates of all monkeys. The patches were more extensive and regressed slower with oxyphencyclimine. Enlarged lesions were seen with the double dose. In Series I intraepithelial invasion by hyphae was detected more frequently and longer after inoculation in the oxyphencyclimine group. Such invasion was not found in biopsies from Series II. It is likely that saliva offers some protection against yeasts colonizing the fitting size of a denture.

Acrylates↗
PubMedDate not supplied

Electrophoresis of whole-cell soluble proteins of microorganisms isolated from bacteremias in endodontic therapy.

We have previously demonstrated that anaerobic bacteria are the microorganisms most frequently isolated from blood following endodontic therapy of teeth with apical periodontitis. Phenotypic characterisation of the isolates suggested that the bacteria in the blood originated from the root canal. The present experiment using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was carried out in an effort to verify these findings, and to further study the microorganisms involved in endodontic bacteremias. Soluble cellular proteins were extracted from 11 reference strains and 26 bacterial isolates recovered from the root canal and blood. These included Propionibacterium acnes, Peptostreptococcus prevotii, Fusobacterium nucleatum, Prevotella intermedia. Actinomyces israelii, Streptococcus intermedius, Streptococcus sanguis. The electrophoretic patterns mostly confirmed the identity of the isolates as determined by the biochemical and antimicrobial resistance tests. Furthermore, with this typing method the species Prevotella intermedia and Prevotella nigrescens could be differentiated. These species had been recovered from both root canal and blood. Also, differences between subspecies of Fusobacterium nucleatum became evident with SDS-PAGE, and the results indicated that the organism recovered from the root canal and blood was Fusobacterium nucleatum subsp. vincentii. The electrophoretic patterns of the different organisms isolated from the root canal and the blood were similar, providing further evidence that the bacteria found in the blood originated from the root canal.

Bacteremia↗
PubMedDate not supplied

Synovial inflammation in active rheumatoid arthritis and psoriatic arthritis facilitates trapping of a variety of oral bacterial DNAs.

OBJECTIVE: To investigate the presence of oral bacterial DNAs in serum and synovial fluid (SF) of patients with active rheumatoid arthritis (RA) and psoriatic arthritis (PsA). METHODS: Serum and SF samples from 16 RA patients, 14 PsA patients, and 9 osteoarthritis (controls) patients were extracted for oral bacterial DNA. This was used in a checkerboard DNA-DNA-hybridization set up, to identify 40 different bacteria. RESULTS: Mean number +/- standard deviation (SD) of oral bacterial species in sera were 6.2 (3.2) in the RA group (p = 0.004) and 5.4 (2.7) in the PsA group (p = 0.009) compared to 2.1 (1.7) in the controls. Periodontitis associated species Porphyromonas gingivalis and Prevotella nigrescens were exclusively detected in RA and PsA. Mean number (+/- SD) of oral bacterial species in SF were 14.0 (6.8) in the RA (p = 0.001) and 19.4 (7.1) in the PsA group (p < 0.001) compared to 4.0 (1.7) in controls. P. gingivalis, Tannerella forsythensis and Prevotella intermedia were exclusively identified in RA and PsA SF. Higher means of DNAs were found in RA SF compared to RA serum (p < 0.001), and in PsA SF compared to PsA serum (p < 0.001). Higher concentrations of bacterial DNAs were found in RA and PsA compared to controls. CONCLUSION: Higher variety and concentrations of oral bacterial DNAs were found in SF compared to serum of RA and PsA patients. These findings indicate that synovial inflammation in RA and PsA may favor trapping of oral bacterial DNAs, suggesting a perpetuating effect of oral pathogens in joint disease.

Adult↗