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J L Saffar

Publications and source records attributed to J L Saffar.

At least 73 records · Page 4Linked to original sources
PubMed1984

A histometric study of the effect of indomethacin and calcitonin on bone remodelling in hamster periodontitis.

The action on bone remodelling of indomethacin, a potent inhibitor of prostaglandin (PG) synthesis, was determined in hamster periodontitis and compared to that of calcitonin. The two treatments reduced the extent of bone resorption considerably but not significantly (NS). The reversal phase, the intermediate step between resorption and formation, was decreased by 33 per cent (NS) by indomethacin and 75 per cent by calcitonin (p less than 0.02). Bone formation was increased by 270 per cent with indomethacin (p less than 0.05) and by 400 per cent with calcitonin (p less than 0.03), compared with untreated animals. This exceeded the extent of bone formation activity in control animals. These data strongly suggest that PG are involved in the mechanism of bone destruction in hamster periodontitis and that PG are potent in vivo uncouplers of bone remodelling as they participate both in an increase in bone resorption and a decrease in bone formation. A partial decrease in reversal lacunae indicates that other factors, also acting as uncouplers, probably take part in the mechanism of bone destruction.

Animals↗
PubMed1982

Quantitative relationship between osteoclasts, osteoclast nuclei and the extent of the resorbing surface in hamster periodontal disease.

Osteoclast activity in terms of number, nucleus content and position in relation to bone surface features was quantitated during experimental periodontal disease. The increase in total osteoclast population, particularly on periosteal rather than endosteal surfaces, was due mainly to the number of cells in direct contact with the bone surface (on-bone osteoclasts). On-bone cell nuclei per mm of bone surface was constantly significantly greater in experimental animals than in controls. There was a positive linear relationship between the extent of resorbing surface and the nucleus content of the on-bone osteoclasts. Thus, in experimental periodontal disease, increases in the number of on-bone osteoclasts are responsible for the changes in the total number of these cells and disease activity is expressed more accurately by the number of nuclei of on-bone osteoclasts per mm of bone surface.

Animals↗
PubMed1982

[Architecture of the mandibular alveolar process in the hamster. Influence on the localization and morphology of periodontal lesions].

The influence of the anatomical characters of the alveolar processes on the morphology of bone destruction during the development of periodontitis seemed to be very important in Man. The purpose of the present study is to check such an association in hamster, experimental model used in periodontal research. A macroscopic study of mandibular alveolar processes of hamsters with periodontal diseases has shown that the destruction aspects of the alveolar processes had constant features, despite variability in the importance of bone destruction aspects of the alveolar processes had constant features, despite variability in the importance of bone destruction between animals: -- the lingual zone of m1 was most affected, -- the alveolar bone destruction was more important on the lingual face than on the buccal face, -- intra-bony lesions developed along a buccal gutter extending from the distal root of m1 to the mesial root of m3. The morphology of these bone destructions corresponded to anatomical features, the most striking being: -- the bone wall surrounding the mesial root of m1, where a dehiscence was present, was extremely thin,-- the lingual bone plate was uniformly this despite localized reliefs which thickened it in places, -- the buccal bone plate was widened by a cervical gutter. It appeared therefore that the localisation and morphology of the periodontal bone lesions in the hamster are related to the anatomy of the alveolar processes.

Alveolar Process↗
PubMed1982

[Development of periodontitis in the hamster. Quantitative macroscopic study of the accumulation of bacterial plaque and of alveolysis].

The purpose of this study was to determine the relationships between bacterial plaque accumulation and alveolar bone resorption during the progression of periodontal disease in the hamster. The results showed that control animals developed a spontaneous periodontitis characterized by a progressive increase in bacterial plaque accumulation and alveolar bone resorption. The experimental animals submitted to high carbohydrate the Keyes 2000 diet accumulated very important quantities of plaque during the experimental period (6 months) and showed important bone loss. It seemed in fact that the Keyes 2000 diet just accelerated a spontaneous phenomenon. The experimental animals developed extensive cervical caries in close relationship with bacterial plaque accumulation. The role of the high carbohydrate diet in the development of this caries is determinant since it was absent in the control animals.

Alveolar Process↗
PubMed1982

[Symmetry of the bone lesions of periodontitis in the golden hamster].

In 8 month old hamsters, a spontaneous bone resorption occurs on both lingual and palatal aspects of the alveolar process, whereas, the buccal aspects are much less severely affected. A periodontitis lasting more than 6 months markedly increased this process in animals of the same age. In both maxillae, similar levels of bone resorption occurred on both left and right quadrants. A parallel degree of involvement was noted in the upper and lower jaws. However, the progress of the lesions seemed less rapid in the maxilla compared to the mandible. For experimental periods less than 6 months, less sever periodontitis could be recorded if macroscopical studies were conducted in the maxillae rather than the mandibles.

Alveolar Process↗
PubMed1979

[Changes in the endosteal bone balance in periodontal disease induced in golden hamsters].

The purpose of this study was to analyze through morphometric analysis, the variations of the endosteal bone balance during experimental periodontal disease induced in the golden hamster. The results showed that the osteoclastic resorption is increased by a factor of 5 (p less than 0.01) and the bone formation reduced by about 50% (p less than 0.01). The bone volume decreased slightly (by 6%) but significantly (p less than 0.01). No correlation between respectively resorption and formation and bone volume was found.

Alveolar Process↗
PubMed1977

A quantitative study of the effects of prolonged calcitonin treatment on alveolar bone remodelling in the golden hamster.

This study was carried out on adult golden hamsters, to correlate the effects of porcine calcitonin on serum Ca and P concentrations with changes in osteoclastic resorption of bone. After 1 month of treatment with 5 MRC units/kg/day, there was little effect on these parameters. On the other hand, the hormone appears to have an effect on the remodelling sequence, as indicated by a large and very significant decrease in the extent of resorption lacunae unoccupied by osteoclasts. It is suggested that the duration of the reversal phase, separating the end of active resorption from the beginning of active bone formation in each remodelling focus, is greatly decreased. This shortening is associated with a prolongation of the bone formation phase, and the extent of osteoid tissue is markedly and proportionally increased in the treated animals. After a prolonged administration, calcitonin does not seem to impede the formation of new osteoclasts, their number being only slightly diminished, but it remains possible that it does continue to inactivate these cells. The effect on the bone remodelling sequence could be either due to direct action on the osteoblasts or their percursor cells, or an indirect action via the osteoclasts.

Animals↗