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R C Page

Publications and source records attributed to R C Page.

At least 127 records · Page 7Linked to original sources
PubMed1987

Serum regulation of collagen biosynthesis in human diploid fibroblasts.

The mechanism by which serum stimulates collagen production by fibroblasts was examined. Fibroblasts were exposed to various concentrations of serum and collagen production and mRNA levels were measured. Collagen production was determined as collagenase digestible radioactivity and collagen mRNA levels were measured using a [35S]UTP-labelled pro alpha 1[I] probe. The results showed that increased collagen production correlated with enhanced mRNA levels. Extra- and intracellular collagen degradation was similar in control and serum treated cultures, and "G1" and "S" phase fibroblasts contained similar levels of collagen mRNA. We conclude that serum regulation of collagen synthesis occurs primarily at the transcriptional level and that activation of collagen synthesis is not coupled to mitogenic stimulation.

Blood↗
PubMed1987

Isolation and characterization of proteoglycans synthesized by adult human gingival fibroblasts in vitro.

The proteoglycans synthesized by fibroblasts derived from healthy human gingivae were isolated and characterized. The largest medium proteoglycan was excluded from Sepharose CL-4B but not from Sepharose CL-2B; it was recovered in the most-dense density gradient fraction and identified as a chondroitin sulfate proteoglycan. The medium contained two smaller proteoglycans; one contained predominantly chondroitin sulfate proteoglycan, while the other was comprised predominantly of dermatan sulfate proteoglycan and was quantitatively the major species. The largest proteoglycan in the cell layer fraction, excluded from both Sepharose CL-2B and Sepharose CL-4B, was found in the least-dense density gradient fraction and contained heparan sulfate and chondroitin sulfate proteoglycan. It could be further dissociated by treatment with detergent, suggesting an intimate association with cell membranes. Two other proteoglycan populations of intermediate size were identified in the cell layer extracts which contained variable proportions of heparan sulfate, dermatan sulfate, or chondroitin sulfate proteoglycan. Some small molecular weight material indicative of free glycosaminoglycan chains was also associated with the cell layer fraction. Carbohydrate analysis of the proteoglycans demonstrated the glycosaminoglycan chains to have approximate average molecular weights of 25,000. In addition, N- and O-linked oligosaccharides which were associated with the proteoglycans appeared to be sulfated in varying degrees.

Centrifugation, Density Gradient↗
PubMed1987

Mitogenic activity of cementum components to gingival fibroblasts.

Cementum forms the interface between root dentin and periodontal ligament through which periodontal connective tissue is attached to root surfaces. We have examined how cementum components influence the biological activities of gingival fibroblasts. Cementum was harvested from freshly extracted human teeth and extracted sequentially with 0.5 mol/L acetic acid, 4 mol/L guanidine-0.5 mol/L EDTA, and bacterial collagenase. The extracts were concentrated and analyzed for mitogenic activity to human gingival fibroblasts. DNA synthesis was assayed by measurement of [3H]thymidine incorporation by quiescent fibroblasts activated to divide, and cell growth was determined by the counting of cells over a 10-day period. Results showed that extracts of cementum stimulated quiescent gingival fibroblasts to synthesize DNA and grow. The stimulation was dose-dependent, and most of the stimulatory activity was extracted by acid. Addition of small quantities of serum potentiated the mitogenic activity to levels greater than those of control cultures containing 10% fetal calf serum. The mitogenic activity was heat-stable, but it was destroyed by trypsin. Neither platelet-derived growth factor (PDGF) nor epidermal growth factor (EGF) was detectable in the cementum extract, and extracts of human dentin and skin contained very little mitogenic activity. We conclude that cementum contains substances capable of regulating the growth of gingival fibroblasts, and that these substances may play an important role in gingival connective tissue formation and regeneration.

Cell Division↗
PubMed1987

Changes in treatment-related concepts of illicit drug abusers related to time in treatment in two residential treatment programs.

This research investigated the effects of two residential drug treatment programs on changing the attitudes the residents had toward three treatment-related concepts over a 10-month time period. The semantic differential evaluative and potency scales of the concepts Therapeutic Community, Counselor, and Group Therapy were administered to the residents of these programs after they were residents for set periods of time. The results of this research showed that the residents rated the evaluative and potency scales of Group Therapy and Counselor higher the longer they remained in the program.

Adult↗
PubMed1986

Proteoglycans synthesized by gingival fibroblasts derived from human donors of different ages.

The proteoglycans synthesized by fibroblasts derived from human donors of ages ranging from 12 years to 68 years have been studied. In addition, the in vitro proliferation rates of the various cell strains were studied and demonstrated that increasing donor age correlated with a decrease in proliferative activity. The incorporation of [35S]-sulfate into proteoglycans decreased with increasing donor age with cells from the oldest donor demonstrating a 50% reduction compared with cells from the youngest donor. Analysis on Sepharose CL-4B of isolated [35S]-labeled proteoglycans for molecular size distribution revealed few differences between the cell-layer-associated proteoglycans of all cell strains studied. However, analysis of the medium-associated [35S]-labeled proteoglycans demonstrated an increase in the amount of small molecular size proteoglycans with increasing age. More specific analysis of the glycosaminoglycan composition revealed an increase in heparan sulfate from 52% to 73% in the cell-layer-associated proteoglycans of cells from the youngest and oldest donors, respectively. Accompanying this increase was a relative decrease in dermatan and chondroitin sulfate content from 24% to 13% and 25% to 16%, respectively, with increasing donor age. Additionally, the degree of N-sulfation of cell layer heparan sulfate increased with age. Heparan sulfate levels increased in the medium as well with increasing age, with a concomitant decrease in chondroitin sulfate. The quantity of medium-derived dermatan sulfate remained relatively evenly distributed throughout the various ages studied. The various differences noted are considered to reflect the general metabolic changes associated with aging. In particular the increase in heparan sulfate content with age is considered to be related to the decreased proliferative activity of the fibroblasts with increasing age.

Adult↗
PubMed1986

Proteoglycans synthesized by cultured fibroblasts derived from normal and inflamed human gingiva.

The in vitro proliferations rates and proteoglycans synthesized by adult human gingival fibroblasts derived from six age- and sex-matched donors of healthy and chronically inflamed gingiva were analyzed. Fibroblasts from inflamed gingiva demonstrated a slower growth rate than cells from healthy tissue. The rate of incorporation of [35S]sulfate into cell layer-associated proteoglycans and the release of these macromolecules into the culture medium did not differ appreciably between the two groups of cells. Similarly, no detectable differences in the overall charge of the proteoglycans synthesized by normal and inflamed gingival fibroblasts, as assessed by their elution from DEAE-Sephacel, were noted. However, Sepharose CL-4B chromatography revealed that the medium-associated proteoglycans made by the inflamed tissue fibroblasts were depleted in one species of chondroitin sulfate proteoglycans and contained more dermatan sulfate than did control cells. In addition, the intracellular proteoglycan pool was found to be greatly diminished in the inflamed tissue fibroblast cell layers. Glycosaminoglycan analysis of the proteoglycans confirmed these observations. Compared to normal gingival fibroblasts, the inflamed tissue fibroblasts released less heparan sulfate into the medium. Additionally, increased levels of dermatan sulfate and depleted amounts of chondroitin sulfate in the medium of inflamed gingival cells were noted. The observed changes were stable through several transfers in culture and indicate that chronically inflamed tissue may contain fibroblasts manifesting a heritable phenotype differing from fibroblasts in normal connective tissue.

Cell Division↗
PubMed1986

Hyaluronic acid synthesized by fibroblasts cultured from normal and chronically inflamed human gingivae.

Hyaluronic acid is an important component of the extracellular matrix of gingivae and its quantity and molecular size appear to be altered under inflammatory conditions. Whether gingival fibroblasts from inflamed tissues synthesize quantities and molecular sizes of hyaluronic acid that differ from normal gingival fibroblasts is not known. To determine this, we isolated fibroblasts from three biopsies each of healthy and chronically inflamed human gingiva and incubated them in the presence of [3H]glucosamine. The release of labeled macromolecules into the medium was approximately 50% greater for the inflamed tissue fibroblasts than for the normal tissue fibroblasts. Of this labeled material, 35% was identified as hyaluronic acid in the medium of inflamed cell cultures, compared to only 25% in normal fibroblast cultures. Sepharose CL-4B chromatography of the labeled material revealed that most of the newly synthesized hyaluronic acid was of large molecular size in inflamed fibroblast cultures. The proportions of [3H]-labeled hyaluronic acid in these peaks varied and indicated that an increase in the amount of large molecular size hyaluronic acid was responsible for the increase in labeled hyaluronic acid noted in the medium of the inflamed tissue fibroblasts. Thus, the decrease in molecular size of hyaluronic acid previously noted in inflamed tissue most likely arises from extracellular factors rather than synthesis of smaller molecular weight species by the fibroblasts. More importantly, however, the differences noted between normal and inflamed gingival fibroblasts persisted over time in culture. This indicates that such differences between the cells may be of a stable and heritable nature.

Chromatography, Gel↗
PubMed1986

Laboratory studies of a family manifesting premature exfoliation of deciduous teeth.

In a previous publication, we described the clinical and radiographic findings of a family in which the children manifested premature exfoliation of the deciduous teeth. We now report for the same family the results of extensive laboratory studies performed on blood and urine, analysis of periodontal microflora, and a family pedigree. We demonstrated the presence of putative periodontal pathogens in the subgingival microflora, elevated levels of serum antibodies reacting to Bacteroides gingivalis, Capnocytophaga gingivalis, and C. sputigena in 2 of the children, and significantly suppressed monocyte chemotaxis in all 3 children. Phosphoethanolamine was found in the urine of the father and all 3 children, but not in the mother. Likewise, serum alkaline phosphatase was abnormally low for all 3 children, and was at the extreme low end of normal range for the father, but was normal for the mother. On the basis of the alkaline phosphatase and phosphoethanolamine measurements, we assigned a diagnosis of hypophosphatasia to the 3 children. Phosphoethanolamine and alkaline phosphatase were also abnormal in the paternal grandmother and her brother. The son of this brother who was deceased had a daughter manifesting premature loss of the primary teeth. The data are consistent with an autosomal dominant mode of transmission. In the light of our findings, hypoplastic cementum must be considered in the etiology of some forms of early-onset periodontitis.

Adult↗
PubMed1986

Gingivitis.

Gingivitis is caused by substances derived from microbial plaque accumulating at or near the gingival sulcus; all other suspected local and systemic etiologic factors either enhance plaque accumulation or retention, or enhance the susceptibility of the gingival tissue to microbial attack. Microbial species specifically associated with gingival health include Streptococcus sanguis 1, S. D-7, and Fusobacterium naviforme. Bacteria involved in the etiology of gingivitis include specific species of Streptococcus, Fusobacterium, Actinomyces, Veillonella, and Treponema and possibly Bacteroides, Capnocytophaga, and Eikenella. Microbial colonization and participation is sequential, with the complexity of the associated flora increasing with time. The pathogenesis has been separated into the initial, early, and established stages, each with characteristic features. The initial lesion is an acute inflammation which can be induced experimentally by application of extracts of plaque bacteria to normal gingiva. The early lesion is characterized by a lymphoid cell infiltrate predominated by T lymphocytes, characteristic of lesions seen at sites of cell-mediated hypersensitivity reactions. The early lesion can be induced by application of purified contact antigens to the gingival tissues of previously sensitized animals. As the clinical condition worsens, the established lesion appears, predominated by B lymphocytes and plasma cells. Established lesions may remain stable for indefinite periods of time, they may revert, or they may progress. Periodontal destruction does not result from the conversion of a predominantly T cell to a predominantly B cell lesion as has been suggested, but rather from episodes of acute inflammation. Clinical manifestations of gingivitis are episodic phenomena characterized by discontinuous bursts of acute inflammation. Most lesions are transient or persistent but not progressive. Attachment loss may precede alveolar bone loss and may occur without the manifestations of a concurrent or a precursor gingivitis. On the other hand, the evidence indicates that a portion of gingivitis lesions can and does progress to periodontitis. Gingivitis and the periodontal microflora differ in children and adults. Clinical signs of gingivitis either do not appear as plaque accumulates, or they are greatly delayed in children, and the inflammatory infiltrate consists mostly of T lymphocytes. The conversion to a B cell lesion does not appear to occur. The evidence supports the conclusion that gingivitis is a disease, and that control and prevention is a worthwhile goal and a health benefit.(ABSTRACT TRUNCATED AT 400 WORDS)

Actinomyces↗
PubMed1986

The effect of chronic inflammation on gingival connective tissue proteoglycans and hyaluronic acid.

Proteoglycans have been isolated and analysed from extracts of normal and chronically inflamed human gingiva in order to determine the effects of chronic inflammation on these important soft connective tissue extracellular macromolecules. The uronic acid content of glycosaminoglycans isolated by papain digestion of normal and inflamed gingiva did not differ significantly. Likewise, electrophoretic analysis revealed that the content of hyaluronic acid, heparan sulfate, dermatan sulfate and chondroitin sulfate was similar. The sulfated glycosaminoglycans from both sources eluted from a Sepharose C1-6B column with a Kav of 0.45 (approximate Mr 25,000). However, hyaluronic acid from normal gingiva was predominantly of a large size eluting in the void volume of a Sepharose. CL-6B column, while that isolated form inflamed tissue was mostly a small molecular weight species which eluted in the included volume of a Sepharose CL-6B column. Using dissociative conditions, intact proteoglycans could be more readily extracted from inflamed tissues (90% of the total tissue uronic acid) than from normal tissues where only 80% of the total tissue uronic acid was extractable. Even though DEAE-Sephacel ion-exchange chromatography revealed no differences in charge between normal and inflamed gingival proteoglycans, Sepharose CL-4B chromatography revealed more molecular size polydispersity in samples from inflamed tissue than from normal tissue. Taken together, these results indicate that while hyaluronic acid is depolymerized in inflamed tissue, no evidence of sulfated glycosaminoglycan degradation was found. Therefore, the most likely cause for disruption to the molecular integrity of the proteoglycans is via proteolytic alteration to the proteoglycan core protein.

Chromatography, Gel↗
PubMed1986

Development of a three-dimensional extracellular matrix synthesized by human diploid fibroblasts in vitro.

Development and maturation of an extracellular matrix, synthesized by human gingival fibroblasts, have been studied microscopically. Pairs of demineralized, fibronectin-coated slices of human tooth root, 300 micron thick, were placed on confluent cell layers, defining a 0.5 mm wide space. The cultures were grown under standard conditions with ascorbic acid (50 micrograms ml-1) added daily. At various times up to 13 weeks, the cultures were fixed and the samples prepared for light and electron microscopy. Cells from the monolayer became attached to, and migrated up, the vertical root surface and, during the time studied, completely filled the space between the root slices with an extracellular matrix. A close association was seen between the cell membrane and collagen fibres in the demineralized surface initially. A thin layer of fibrillar material was deposited between the cell and the vertical surface, and eventually an extracellular matrix surrounding the cells and attaching to the root surface was present. Samples fixed in the presence of Ruthenium Red showed intense staining of the fibrillar material, indicating the presence of anionic molecules. Additional cells migrated onto the newly synthesized matrix and up the root surface. Growth of the fibrillar networks on either side, horizontally and vertically, continued and, eventually, an extracellular matrix attaching to the vertical surfaces completely filled the previously empty space. Immunocytochemical staining showed that the matrix contained hyaluronic acid, chondroitin sulphate, dermatan sulphate and fibronectin at this time. Collagen fibres were observed at 6 weeks, and at later times collagen types I, III and V were the primary matrix components. The fibroblasts attaching to the root slice and those present at the edge of the matrix had an elongated, polar form. The cells within the matrix frequently showed a stellate appearance with numerous extended processes, in contact with fibrillar material or collagen fibres. Fibroblast processes were at later times seen to enclose bundles of collagen fibres and to mediate cell-to-cell contact, occasionally via desmosome-like structures. The structure and composition of the matrix and the appearance and apparent behaviour of the cells were similar to that observed in the healing wound. This system thus could provide a model for studying various aspects of regeneration of extracellular matrix.

Collagen↗
PubMed1986

Current understanding of the aetiology and progression of periodontal disease.

There is overwhelming evidence that bacteria cause periodontitis and that they do so by extending apically along the surfaces of the tooth roots and creating pockets. A very complex mixture of microbial species, mostly although not exclusively gram-negative, anaerobic, and motile, is involved. Infection probably occurs in a progressive and sequential manner. The bacteria involved include various species of Bacteroides, Actinobacillus, Eikenella, Fusobacterium, Capnocytophaga, and Eubacterium. Local oral conditions such as tooth position play an aetiologic role by affecting plaque accumulation and retention. Host defence factors, particularly the phagocytic cells and the immune system, play a determinative role in the aetiology by monitoring, controlling, and regulating microbial colonization and infection. These diseases begin as an acute inflammation of the marginal gingiva, and they progress through orderly stages to the formation of a gingival pocket. Transition from gingivitis to periodontitis is not well-understood, but it probably involves colonization by additional microbial species or invasion of the periodontal tissue by species already present. Progression of periodontal destruction is episodic, possibly as a consequence of successful host defence. In most patients, periodontal destruction occurs more infrequently than previously suspected. In both treated and untreated patients, a small subgroup accounts for most of the disease activity. The most important problem we now face is to develop diagnostic methods to identify individuals in this subgroup and devise ways to prevent and control their diseases.

Bacteria↗