摘要:

The growth fraction in the mouse periodontal ligament (PL) was determined by means of continuous labelling for up to 60 days with3H‐Tdr via the drinking water. The method was tested by comparing the labelling indices (LI) of PL cells obtained in this way with those obtained by repeated injections or via osmotic mini‐pumps. There was no significant difference between the LI obtained by the 3 different routes. Cell density was assayed in the PL of mice who had received no3H‐Tdr or that were labelled for 60 days with3H‐Tdr. There were no detectable differences in cell density, and we concluded that3H‐Tdr cytocide did not significantly change the growth fraction. The growth fraction of PL cells was 30%, and 25 days of continuous labelling were required to obtain this value. No significant change of LI was observed between 25 and 60 days of labelling. This plateau could not be accounted for by loss of PL cells to bone as osteocytes because very few labelled osteocytes were observed, even after 25 days of continuous labelling. The growth fraction of cells within 10 μm of blood vessels was 40% and was significantly higher than the overall growth fraction. These data suggest that cell division in the PL occurs predominantly in a paravascular location and that some of the progeny of dividing cells in

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00357.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Isolationin vitroof clonal populations of fibroblasts from enzyme digested porcine periodontal ligament (PL) has made possible the comparison of collagen synthesis between single colonies of cells. Despite low cloning efficiencies, two independent PL isolations yielded enough clones for detailed analysis. In the first group of clones, the amount of14C‐labelled collagen synthesized compared to the total protein synthesis varied from 32% to 47%, whereas the values from the second group, with one exception, ranged from 55% to 70%. Each clone synthesized types I, III, and V collagens. However, the relative amounts of these collagens varied from one clone to another in both groups: i. e. the type III collagen synthesis ranged from 10% to 32% of the total collagen in most clones. A single clonal population produced type I collagen almost exclusively and in another collagen synthesis was barely detectable. These results indicate that primary cultures of PL cells contain a heterogenous mixture of cells that not only synthesize different levels of collagen but produce distinctly different ratios of collagen types. These findings further suggest that the PL contains distinct populations of fibroblast‐like ce

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00358.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Fibroblasts of the rat periodontal ligament were studiedin situby the freeze‐fracture technique. Large surfaces of the protoplasmic and extracellular faces of the cell membrane as well as, the membranes of the RER, Golgi apparatus, and other cytoplasmic organelles were viewed at the ultrastructural level. Intramembrane particles representing membrane proteins were visualized, and their concentration in various membranes measured.Features of the fibroblast cell surface appearing as rough patches were interpreted to represent areas of possible cell‐to‐matrix interaction. The use of the freeze‐fracture technique in further studies of PDL fibroblast‐matrix contact is

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00359.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The aim of the resent study was to investigate the histopathological characteristics of artificial periodontal defects before and after removal of ligatures. The defects were created in 12 young adult beagle dogs using cotton floss ligatures. The supracrestal dentogingival fibres were dissected around 6 lower premolars (2P2,3P3, and4P4) after which closely adapted copper bands were cemented to the teeth. After 3 weeks these copper bands were replaced by subgingival cotton floss ligatures which were left in place for a further 11 weeks. The placement of ligatures around the different teeth and their removal prior to sacrifice was scheduled to provide histological observations of the periodontal defects both with ligatures in situ, and 1 day and 1, 3, 7, 15, or 31 weeks after their removal.Defects with ligatures in situ showed histopathological characteristics of advanced chronic periodontitis. Removal of the ligatures and the subsequent production of a notch (to mark the bottom of the pocket) resulted initially in an exacerbation of the inflammatory process but 3 weeks after ligature removal, a distinct decrease in size of the infiltrated connective tissue (I. C. T.) could be observed especially in the deeper part of the lesion. The tissues of the periodontium showed signs of repair whack became more pronounced with time. There was no indication that the lesion had become progressive in the remaining period of 7–31 weeks after ligature removal.It is concluded that the maintenance of the established lesion is dependent on the persistence of subgingival plaque containing ligature

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00360.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Following blockage of eruption of continuously erupting teeth in rodents, regressive changes occur in the marginal periodontium resulting in detachment of periodontal ligament from the root surface and concomitant apical migration of the functional epithelium. In the present investigation we attempted to identify the mechanisms that are possibly responsible for these changes which occur in the absence of dental plaque.Mice were killed at time intervals varying from one hour up to nine months following pinning their lower right incisor to the surrounding alveolar bone. Stereologic analysis of ultrathin sections revealed that, on the pinned side, the collagen content of the periodontal ligament adjacent to the apical termination of the functional epithelium was substantially less as compared with the ligament at more apical levels. The low volume density of collagen close to the functional epithelium was accompanied by a relatively high amount of phagocytosed collagen in fibroblasts. The volume density of collagen‐containing vacuoles in these cells correlated well with the rate at which the periodontal ligament was detached from the tooth, thereby suggesting that collagen degradation in this area is likely to be performed by connective tissue cells. In addition, it was observed that layers of afibrillar cementum were deposited against the root surface. This would seam to suggest a local disturbance in the incorporation of periodontal ligament fibers in the cementum and could possibly facilitate therapid apical progression of the junctional epithelium during the course of the experimen

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00361.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The cellular and humoral responses in ovalbumin (OVA) presensitized germfree rats fed OVA (SAF), in an otherwise antigen‐free diet, were compared to sham‐sensitized animals that were also fed OVA (SSAF). Sensitized animals demonstrated relatively more lymphocytes in their gingival tissues. An initial predominance of T lymphocytes gave way to a predominance of B‐lymphocytes. Splenic lymphocytes from presensitized animals showed significant blastogenesis at the time antigen feeding was initiated. Sensitized animals showed elevated blastogenesis throughout the feeding period whereas the sham‐sensitized animals showed some elevated responses only after 38 days of antigen feeding. The plasma IgG response to OVA was markedly elevated in the sensitized animals, in contrast to a low or nonexistent IgG antibody response in the sham‐sensitized rats. On the other hand, IgA anti‐OVA responses in intestinal perfusates were elevated in the SAF group for the first 14 to 21 days of feeding. Early salivary IgA responses (0 to 21 days) were essentially the same between the groups, but later (38 to 84 days) both IgA and IgG responses in saliva were elevated in the SAF group. Sensitized animals demonstrated significantly elevated periodontal bone loss after 84 or 128 days of OVA feeding. The potential effects of “mixed” hypersensitivity on periodontal disease in the ra

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00362.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00363.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

A modified implantation technique was used to study the early tissue reactions to three periodontal dressings (Coe‐pak, Peripac, and Wondrpak). The dressings were placed in contact with an intact non‐epithelialized tissue surface for 15 minutes and 3 days. The tissue reactions were assessed by histochemical and histological techniques. After 15 minutes of tissue‐material contact, the most severe tissue reactions were caused by Wondrpak. When the contact period was increased to 3 days, Peripac generally showed a more severe tissue response than Wondrpak. At both contact periods Coe‐pak had caused the mildest re

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00364.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Pieces of human masticator mucosa were maintained in a Trowell‐type organ culture. The explants were placed on their side on either microporous filters or decalcified dentin matrix slices. The presence of serum in the culture medium enhanced epithelial outgrowth (epibolus) from the explants. The epibolus grew longer in contact with the substratum than along the free connective tissue surface of the explant.When grown on microporous filters, the flow of migrating cells was directed between the explant and substratum. As a sign of epithelial attachment to the filter, a structure morphologically similar to basal lamina and hemidesmosomes was seen. The decalcified dentin matrix, however, caused the epithelial cells to migrate outwards from the explant. The explants became loosely attached to the matrix. Although some electron‐dense material was secreted into the contact area, a typical basal lamina was not s

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00365.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Neuraminidase activity in human crevicular fluid by an improved assay procedure was initially demonstrated. The mean values of the activity in periodontally healthy and diseased patients were 11–12 and 144–155 a units per total fluid collected for 10 min, respectively. The activity showed significant correlations (p<0.01) with clinical findings, that is, Debris Index, Calculus, Index, Gingival Index, and pocket de

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1983.tb00366.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY