Effect of cell donor age on the synthetic properties of fibroblasts obtained from phenytoin-induced gingival hyperplasia

Diploid fibroblasts obtained from explants of human gingiva and maintained in vitro undergo a several-fold decrease in protein and collagen synthesis as a function of increasing donor age. Using drug-induced gingival hyperplasia as a model, we performed experiments to learn whether fibroblasts derived from hyperplastic tissue behave in a similar manner. Fibroblast strains were established from explants of hyperplastic gingiva obtained from 10 patients chronically ingesting phenytoin and ranging in age from 9 to 45 years. Protein production and degradation were compared to previously reported data similarly obtained from periodontally normal donors ranging in age from 12 to 68 yr. The total quantity of protein and collagen produced by the phenytoin cells was significantly greater than previously reported for cells from normal gingiva. No donor age-related decrease in protein and collagen production nor in the proportion of cell synthetic activity committed to collagen production was observed for cultures of phenytoin cells. The gross pattern of proteins produced, as assessed by 2-dimensional gel electrophoresis, was unrelated to donor age in both normal and phenytoin cells, but three polypeptides ranging in size from about 20 kD to 40 kD that were not found in the cultures of normal cells were produced by five of seven phenytoin cells strains. The observations demonstrate that the phenytoin cells do not undergo the donor age-dependent decrease in synthesis observed for normal cells. This abnormality may account in part for the phenytoin-induced hyperplasia. The phenytoin cells appear to be a unique phenotype.

Hyperthermia for the treatment of brain tumors

Brain malignancy, either primary or metastatic, in general is associated with a very poor outcome in spite of the best therapy modern medicine has to offer. The multimodality approach appears to offer the best chance of achieving our goal of improved survival (quality and quantity) and ultimately cure. Hyperthermia, though its application to brain cancer remains experimental, has proven itself in its ability to improve cancer therapy results. There are many methods available to apply hyperthermia to the brain and its application, thus far, has been quite safe. Continued research in this exciting field is warranted.

Relationship between levels of aspartate aminotransferase in gingival crevicular fluid and gingival inflammation

Data from several sources demonstrate that disease-active and disease-inactive periodontal pockets exist, but currently available diagnostic procedures do not permit identification of disease-active sites at any given point in time. Using the experimental gingivitis model, we have performed studies aimed at determining whether levels of the enzyme aspartate aminotransferase (AST) in gingival crevicular fluid correlate with the presence and extent of periodontal inflammation. Gingival inflammation was assessed using the Gingival Index and the Sulcular Bleeding Index, and enzyme activity was measured using a standard procedure. Our data reveal a statistically significant association between AST values and Gingival Index scores for spontaneously occurring lesions (p less than 0.02-0.04) and experimentally induced lesions (p less than 0.0001), as well as the extent of change in these values during developing experimental gingivitis (p less than 0.0001) and resolving experimental gingivitis (p less than 0.0001). The data demonstrate that AST levels can be used to assess the presence and extent of periodontal inflammation.

Detection of a high-affinity binding site for the globular head regions of the C1q complement protein on a human diploid fibroblast subtype

A cultured fibroblast subtype with growth and synthetic properties expected of cells residing in healing wounds and in inflammatory lesions binds the Clq component of complement with a functional affinity much higher than that of the remaining cell population. In this study we examined the optimal conditions that favor the interaction between purified 125I-labeled Clq and this cell subtype, following its isolation from the parent culture using a cell sorter, and assessed the biologic consequences of binding. Binding of 125I-Clq to the cell surface is specific, saturable and reversible. It is maximal between pH 5.5 and 8.5 at an ionic strength of mu = 0.10 and decreases as a function of increasing salt concn, with half saturation near physiologic ionic strength. Scatchard analysis of binding data indicates a single class of sites with an average association constant in the order of 1.5 x 10(9)/M and an average number of 2.5 x 10(6) binding sites per cell. Unlabeled globular fragments of Clq inhibit intact 125I-Clq binding by 64%, while unlabeled collagen-like fragments have no effect. Thus it appears that binding of Clq to this high-affinity site is mediated by a region of the globular domain of the molecule. Only the fibroblast subtype with binding sites for the globular domain of Clq appear to have the capacity to induce non-immune activation of the classical complement cascade, as assessed by the generation of C4a and C4d fragments in normal AB serum following exposure to the cells. This activation may generate products that account for a previously reported complement mitogenicity for fibroblasts.

Effects of interleukin-1 on fibroblast extracellular matrix, using a 3-dimensional culture system

This study describes the alterations induced by Interleukin-1 alpha and -beta (IL-1 alpha and IL-1 beta) on fibroblast-synthesized extracellular matrix. Fibroblasts were grown between pieces of dentin or in collagen-coated Terasaki wells for 3 or 6-9 weeks to create 3-dimensional cell-containing matrices constituted primarily of proteoglycans and collagens, respectively. Following incubation with IL-1 alpha or IL-1 beta (10(-9) M) at 37 degrees C for 24 or 72 hr, samples were prepared for light and electron microscopy. Both IL-1 alpha and IL-1 beta induced collapse of the extracellular matrix by 72 hr, as manifested by a decrease of the cross-sectional area and an increased density of the matrices. Three-week matrices were reduced 26% and 45% by using IL-1 alpha and IL-1 beta, respectively. Comparable values obtained by using 6-week matrices were 14% and 30%. Cells within the matrix, normally stellate in shape with numerous extended processes, attained a more rounded or spindle shape with few and reduced processes and showed apparent alterations at cell matrix attachment sites and rearrangement of the cytoskeleton. Elongated cells at the top of the matrix appeared more compressed. The alterations were more pronounced in cultures incubated with IL-beta than with IL-1 alpha. Immunocytochemistry of extracellular matrix components revealed a decrease in staining intensity of chondroitin and dermatan sulfate in the 3-week matrix following IL-1 beta incubation. There was also a decrease in collagen type 1 staining of 9-week matrices treated with IL-1 alpha or IL-1 beta. These studies show that IL-1 has an effect on fibroblast-synthesized extracellular matrix and indicate that the effects of IL-1 alpha and IL-1 beta may differ. The resulting collapse of the matrix appears at least in part to be due to changes in proteoglycans and collagens.

Collagen synthesis by human fibroblasts. Regulation by transforming growth factor-beta in the presence of other inflammatory mediators

We have examined the combined effects of transforming growth factor-beta (TGF-beta), serum and gamma-interferon (gamma-IFN) on collagen synthesis by fibroblasts and compared the response of fibroblast subpopulations to TGF-beta. Human diploid fibroblasts were treated with TGF-beta alone and with serum of gamma-IFN. Cells were labelled with radioactive amino acids, and collagen production was measured as collagenase-digestible radioactivity. Collagen mRNA was determined by a solution-hybridization assay using procollagen-alpha 1[I] cDNA clone HF 677. The results showed that either serum or TGF-beta increased incorporation, collagen production and mRNA by fibroblasts approx. 2-fold; however, collagen synthesis relative to total protein synthesis and collagen mRNA relative to total polyadenylated [poly(A)+] RNA were not affected. Only serum activated cell growth. Collagen production increased approx. 4-fold in cells exposed to both TGF-beta and serum, and this increase was equal to that expected for an additive effect by both components. Treatment with gamma-IFN decreased collagen production and collagen mRNA to 44 and 40% respectively, whereas total incorporation and poly(A)+ RNA were affected only marginally. Cells exposed simultaneously to both gamma-IFN and TGF-beta produced less collagen and contained less mRNA than did those treated with TGF-beta alone. The gamma-IFN decreased collagen synthesis in control and TGF-beta-treated cultures to a similar extent, and TGF-beta increased collagen synthesis 2-fold in cells pre-treated with gamma-IFN. Fibroblast strains obtained in medium containing plasma-derived serum synthesized approximately half as much collagen as did cells derived from the same explant in the presence of fresh human serum, and TGF-beta stimulated collagen production and mRNA in both cell strains. We conclude that TGF-beta, serum and gamma-IFN regulate collagen synthesis by independent mechanisms, and that the combined action of these components plays a significant role in regulating collagen synthesis during wound healing and tissue repair.

The role of proteoglycans in collagen gel contraction by human gingival fibroblasts

Fibroblasts generated from biopsies of normal gingiva contract collagen gels to a significantly greater extent than do fibroblasts generated from chronically inflamed gingiva. The present study demonstrates that proteoglycans play a major role in gel contraction, and that cells from the two sources differ greatly in their ultrastructural features and their capacity to synthesize proteoglycans. Fibroblasts from normal gingiva contained more rough endoplasmic reticulum and mitochondria, and they were more well-spread than cells from chronically inflamed gingiva. We observed a fine granular electron-dense lamina of material especially prominent around the cell processes and on the surface of the collagen fibrils. This material appears to be rich in proteoglycans since it stained with ruthenium red, a dye that binds to proteoglycans, and labeled in cultures incubated for 1 or 4 hr in medium containing 35S-sodium sulfate. Proteoglycans have the capacity to bind matrix components to one another and to cells, and thereby play a major role in gel contraction. Normal fibroblasts have a significantly greater capacity to synthesize proteoglycans, as manifested by label incorporation, that do cells from inflamed tissue, and this may account for their greater capacity to contract collagen gels in vitro.

Isolation of noncollagenous proteins from gingival connective tissue

Noncollagenous proteins form an integral part of gingiva and other connective tissues. We have performed studies aimed at purification and partial characterization of the gingival noncollagenous proteins. Healthy gingival tissues from mongrel dogs were extracted in neutral buffers, acetic acid, and 6 mol/L urea. Immunoblots using anti-keratin antibodies and CNBr peptide patterns revealed that the majority of the proteins present in these extracts were keratins. To exclude keratins, gingival connective tissue was separated from the epithelium and then extracted. Acid extracts of the connective tissue contained very little protein, whereas urea extracts contained collagen and other noncollagenous proteins. The noncollagenous proteins present in the urea extract were partially purified by DEAE-cellulose chromatography and separated by affinity chromatography through a Sepharose 4B-type I collagen column. At least eight proteins, which ranged in molecular size from 15 to 75 kilodaltons, were obtained by this procedure. We conclude that keratins are major components of whole gingiva extracts and that epithelium must first be removed in order for connective tissue proteins to be obtained. The gingival connective tissue appears to contain several collagen-binding proteins, and these proteins may play an important role in the structure and function of the gingival matrix.

Role of platelet factors and serum complement in growth of fibroblasts with high-affinity Clq complement receptors

Cultures of human diploid fibroblasts are heterogeneous in that a subpopulation interacts via high-affinity receptors with the globular head regions of the Clq complement protein. Growth and synthetic properties of these cells are characteristic of cells residing in healing wounds and inflammatory lesions. At these sites, fibroblasts are exposed to regulatory molecules such as complement components and factors released from blood platelets. We assessed the effects of native complement proteins and platelet-derived factors on proportions and phenotypic stability of high-affinity and low-affinity receptor cells generated from explants of adult and embryonic connective tissue, using radioligand binding assays and immunofluorescence analysis by flow cytometry. Fibroblasts expressing high-affinity Clq receptors could be generated from explants only when factors from platelets were present in the medium; native complement proteins were not essential. High-affinity receptor cells could be generated only from tissue; they could not be generated by incubating cultures of the low-affinity receptor phenotype in medium containing platelet-derived factors. High-affinity receptor cells, once established from explants in the presence of platelet-derived factors, persisted through many replications in the absence of platelets. We obtained the same fibroblast phenotypes from embryonic skin as from adult gingiva, but the proportion of high-affinity receptor cells from skin was much greater. We conclude that factors derived from platelets are essential for generating cultures containing fibroblasts expressing high-affinity Clq receptors, but not for their maintenance. High-affinity receptor cells may comprise a rapidly dividing subpopulation giving rise only to like progeny or to other, more differentiated cells.

The effects of two therapeutic communities on illicit drug users between 6 months and 1 year after treatment

Thirty former residents of two different therapeutic communities for illicit drug users were interviewed between 6 months and 1 year after terminating treatment to determine how successfully they had been in adjusting to society. Two findings of this research concerned the amount of time the former residents spent in their therapeutic communities: Time in treatment was associated with fewer arrests once they graduated from these programs and was also associated with less drug use.

The Therapeutic Community Involvement Scale: an instrument for assessing the staff perceptions of the therapeutic involvement of illicit drug abusers

The Therapeutic Community Scale is described. This instrument has two subscales: the Participation Scale and the Self-Disclosure Scale. Counselor ratings of residents on this scale improved, the longer residents remained in two therapeutic communities.

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.

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.

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.

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.

Effects of donor age on protein and collagen synthesis in vitro by human diploid fibroblasts

Diploid fibroblast strains were established from explants of normal gingiva from donors ranging in age from 12 to 68 years. By using labeled amino acid precursors, we measured protein and collagen production, and intra- and extracellular protein degradation. Qualitative assessment of the patterns of protein production was performed by two-dimensional gel electrophoresis and detection of labeled components by fluorography. Protein and collagen production decreased more than 5-fold as a function of increasing donor age over the age range studied while protein degradation remained unaffected by donor age. The pattern of proteins produced was unaffected by donor age. These data demonstrate a large statistically significant slowdown in general protein synthesis with increasing donor age. This slowdown is not selective, but appears to affect all of the proteins being produced.

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.

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.