Biomedical subjects

D N Tatakis

Publications and source records attributed to D N Tatakis.

42 records · Page 3Linked to original sources

PubMed1989

Leukotrienes in orthodontic tooth movement.

Prostaglandins (PGs) and leukotrienes (LTs) are products of arachidonic acid conversion. PGs have an established role in mediating orthodontic tooth movement. The role of LTs in modulating or mediating orthodontic tooth movement was investigated in this study. One hundred thirty-two Sprague-Dawley rats were used; the animals weighed 300 to 400 gm with equal numbers of male and female rats. They were divided into five main groups of 24 animals each and a sham group of 12 animals. An orthodontic appliance was placed and activated on all the animals except the sham group; in this group the appliances were not active. Each main group was given one of the following treatments daily: distilled water, 5% gum arabic solution, PG synthesis inhibitor indomethacin, LT synthesis inhibitor AA861, and a combination of both drugs. Each group was divided into six subgroups of four animals; the animals were killed at either 1, 3, 5, 7, 10, or 14 days, and tooth movement measured. The three sham subgroups received distilled water and were killed at 1, 7, or 10 days. The first maxillary molar (the moved tooth) and surrounding tissues were removed from all animals in the sham group and the subgroups killed at 1, 7, and 10 days in the gum arabic solution group and the LT synthesis inhibitor group. Prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) were extracted, measured with radioimmunoassay (RIA), and standardized per milligram of protein in the sample. A significant inhibition of tooth movement occurred beginning on day 7 in the indomethacin, AA861, and combination groups; there was no significant difference among these groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

Recombinant interleukin-1 stimulates prostaglandin E2 production by osteoblastic cells: synergy with parathyroid hormone.

Recombinant mouse IL-1 (Interleukin-1) has been shown to be capable of stimulating prostaglandin E2 (PGE2) production by isolated rat osteoblastic cells in a dose-dependent manner. The rapidity of the effect (1 hour) and the potency of IL-1 (5 x 10(-12) M) in producing this effect suggest that IL-1 may exert some of its effects on bone via PGE2. Parathyroid hormone (PTH) appears to have a strong synergistic effect with IL-1. These data further substantiate the role of IL-1 in bone physiology.

Animals↗

PubMed1986

The use of monoclonal antibodies to detect Bacteroides gingivalis in biological samples.

Hybridomas were established which produce monoclonal antibodies specific for Bacteroides gingivalis, a pathogen associated with human periodontal disease. Spleen cells from BALB/c mice immunized with formalinized B. gingivalis were fused with Sp2/0-Ag14 myeloma cells. Of 1,050 wells with positive growth, 60 contained antibody reactive with the immunizing strain of B. gingivalis by enzyme-linked immunosorbent assay. Expansion of these cultures and cloning by limited dilution resulted in 28 clones which reacted with B. gingivalis but not with other orals and nonoral black-pigmented Bacteroides species or any of 29 representative strains of other oral bacteria. Of these 28 clones, 14 were also specific for B. gingivalis by indirect immunofluorescence microscopy. One clone, BBG-12 producing immunoglobulin G2b(kappa), was chosen to identify B. gingivalis in subgingival plaque because of its high reactivity in indirect immunofluorescence assays. This antibody reacted strongly with all 17 representative B. gingivalis strains obtained from diverse sources. Furthermore, when this reagent was applied to subgingival plaque samples, B. gingivalis was stained with high specificity and low background fluorescence, indicating that it may be useful for clinical identification of this organism.

Antibodies, Bacterial↗

PubMedDate not supplied

Histologic evaluation of hydroxyapatite-coated root-form implant retrieved after 7 years in function: a case report.

This case report presents a clinical, radiographic, and histologic evaluation of 2 non-adjacent, hydroxyapatite-coated, root-form implants retrieved from the maxillary canine area of a patient after 7 years in function. Clinical examination revealed immobile implants with no sign of pathosis. Radiographic examination indicated close proximity of the bone to the implant surface without evidence of radiolucency. Histologically, the 2 implants appeared to be well integrated with the surrounding bone; 84% of the surface of the first implant and 79% of the surface of the second implant had close bone apposition at the interface. There was no evidence of dissolution of the hydroxyapatite coating. The bone appeared to be in immediate contact with the coating. These observations suggest that a particular hydroxyapatite coating on root-form implants can resist degradation during long-term function.

Aged↗

PubMedDate not supplied

Bone formation and reosseointegration in peri-implantitis defects following surgical implantation of rhBMP-2.

This study was designed to evaluate bone formation and reosseointegration following surgical implantation of recombinant human bone morphogenetic protein-2 (rhBMP-2) in peri-implantitis defects. Hydroxyapatite-coated dental implants were placed bilaterally in the mandibular and maxillary premolar area in four rhesus monkeys and were allowed to osseointegrate for 1 year. Cotton ligatures were then placed around the healing abutments, and plaque was allowed to accumulate for 11 months. Resulting circumferential peri-implantitis defects exhibited a large intrabony and horizontal component. At reconstructive surgery, peri-implantitis defects in contralateral jaw quadrants were randomly assigned to receive rhBMP-2 (0.43 mg/mL implant volume) in an absorbable collagen sponge carrier or a carrier control. The animals were sacrificed 4 months postsurgery, and block sections were prepared for histometric analysis. Summary statistics included means calculated per animal. Paired t tests were used to evaluate differences between experimental conditions (n = 4). Defect depth amounted to 3.4 +/- 0.9 mm and 3.2 +/- 0.9 mm for rhBMP-2 and control defects, respectively. Vertical bone gain in rhBMP-2 defects (2.6 +/- 1.2 mm) was significantly greater than in controls (0.8 +/- 0.8 mm; P < .01). Reosseointegration within the confines of the defect for rhBMP-2 defects (29.0 +/- 10.5%) differed significantly from that in the control (3.5 +/- 2.5%; P < .01). Reosseointegration within the extent of newly formed bone averaged 40.0 +/- 11.0% in rhBMP-2 defects as compared to 8.9 +/- 7.8% in the control (P < .01). Osseointegration in resident bone amounted to 69.5 +/- 6.9% and 72.6 +/- 8.0% for rhBMP-2 and control defects, respectively. There is significant evidence that rhBMP-2 has potential to promote bone formation and reosseointegration in advanced peri-implantitis defects in a demanding nonhuman primate model.

Alveolar Bone Loss↗

PubMedDate not supplied

Bone formation and osseointegration stimulated by rhBMP-2 following subantral augmentation procedures in nonhuman primates.

The purpose of this study was to evaluate bone formation and osseointegration using titanium dental implants in the subantral space following surgical implantation of recombinant human bone morphogenetic protein-2 (rhBMP-2). In each of four cynomolgus monkeys, one subantral site was treated with rhBMP-2 (0.19 mg per implant) in an absorbable collagen sponge (ACS). The contralateral site was treated with vehicle in ACS (control). Three months later, two screw-type titanium dental implants were placed into each augmented sinus, and one additional implant was placed immediately anterior to the sinus. Thus, each animal had three experimental sites: rhBMP-2, control, and nonsinus. Animals were sacrificed after an additional 3 months, and block sections were harvested and prepared for histometric analysis. Analysis of variance and t tests were used to evaluate differences between experimental conditions. Mean (+/- SD) vertical bone gain was significantly greater in rhBMP-2 than in control sites (6.0 +/- 0.3 versus 2.6 +/- 0.3 mm; P < .002). Bone density in rhBMP-2 sites averaged 14.4 +/- 2.9% versus 13.9 +/- 4.6% and 14.1 +/- 3.6% for control and nonsinus sites, respectively, without significant differences between experimental conditions. Bone-implant contact in rhBMP-2 sites (41.4 +/- 7.7%) was not significantly different from that in control (38.9 +/- 12.4%) and nonsinus sites (46.8 +/- 10.6%). The present study provides evidence for considerable vertical bone gain in the subantral space following surgical implantation of rhBMP-2, thus allowing placement of dental implants. The newly formed bone appears to be of similar quality and to be as suitable for osseointegration as the residual bone in this nonhuman primate model. Thus, surgical implantation of rhBMP-2 appears to have clinical utility and may provide a realistic alternative to autogenous bone grafts for subantral augmentation procedures.

Analysis of Variance↗