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Biomedical subjects

K Arvidson

Publications and source records attributed to K Arvidson.

At least 37 records · Page 2Linked to original sources
PubMed1991

Growth regulation of serum-free cultures of epithelial cells from normal human buccal mucosa.

Human buccal epithelial cells have been reared from explants maintained in supplemented MCDB 153 medium. Primary epithelial outgrowths show typical structural features and uniformly express keratins; subunit analyses demonstrate expression of keratins 5, 6, 14, 16/17, and 19. The cells exhibit up to 6% colony forming efficiency and divide at about 0.8 population doublings per day on fibronectin/collagen-coated dishes at clonal density. Studies of markers of proliferation and differentiation in buccal epithelial cells indicate that epidermal growth factor, cholera toxin, retinoic acid, and pituitary extract each exhibit a distinctive ability to enhance growth and variably affect cell migration and cell surface area. Transforming growth factor beta-1 inhibits growth and increases surface area without affecting migration, involucrin expression, and cross-linked envelope formation. Moreover, exposure of cells to fetal bovine serum, the tumor promoting agent 12-O-tetradecanoylphorbol-13-acetate or an elevated Ca2+ concentration (from 0.1 to 1 mM) inhibits growth and induces squamous differentiation as indicated by inhibition of migration, increases in surface area, involucrin expression, or formation of cross-linked envelopes. The results show that epithelial cells can be reproducibly derived from explant cultures of human buccal mucosa specimens and the cells transferred under serum-free conditions. Buccal epithelial cells in culture undergo a pattern of growth and differentiation that mimics parakeratinization in vivo and variably respond to several agents shown to modulate growth of cells that originate from other types of epithelia.

Animals↗
PubMed1991

Development of low- and high-serum culture conditions for use of human oral fibroblasts in toxicity testing of dental materials.

With the aim of establishing conditions applicable to the testing of dental materials in human target cells, fibroblastic cell lines have been derived and grown from explants of human oral mucosa. Both a high-serum medium (termed "HSM") (CMRL 1066 supplemented with 10% fetal bovine serum) and a low-serum medium (termed "LSM") (a 1:1 mixture of M 199:MCDB 153 supplemented with 1.25% serum) supported radial outgrowths of cells from oral explants, as well as the subsequent transfer and growth of the cells in mass culture and at clonal density. Cells were typically fibroblastic in that they expressed vimentin uniformly, but did not express immunocytochemical markers of epithelial or endothelial cells. Cells derived in either LSM or HSM showed significantly higher colony-forming efficiency and clonal growth rate when transferred in LSM, as compared with HSM. Because cell migration occurred to a lesser extent in LSM, microscopic scoring of colony formation was also markedly facilitated. In both LSM and HSM, cellular low-molecular-weight thiols constituted about 30% of the total amount of sulfhydryls. Glutathione was present in about six- to seven-fold-higher amounts than cysteine--glutathione primarily in its reduced form and cysteine primarily in its oxidized form. A corrosion product of dental amalgam, i.e., Hg2+, decreased cell survival measured as colony-forming efficiency in a dose-dependent manner following either an acute (one h) exposure or continuous exposure (seven days). These studies demonstrated that human oral fibroblasts could be cultured at about one-tenth of the serum content that is commonly used.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood↗
PubMed1990

Histology of tissues surrounding single crystal sapphire endosseous dental implants: an experimental study in the beagle dog.

9 single crystal sapphire dental implants were installed bilaterally into pre-extracted areas in the lower jaw of two beagle dogs and histologically analysed after 180 days in situ. 8 implants were stable and radiographs disclosed complete bone healing. Light-, scanning- and transmission electron microscopy demonstrated that the stable implants were surrounded by a mineralizing bone boundary and a mucosa nearly free from inflammatory cell infiltrations. The 9th implant was mobile and surrounded by a non-mineralized connective tissue capsule containing bundles of collagen. The ultrastructure of the mucosa surrounding the implants closely resembled the mucosa surrounding the tooth. Histometric analysis of the alveolar bone surrounding the stable implants revealed that the value of the bone contact surface ranged from 37.1% to 86.9% (mean value 61.8%) at the light microscopic level.

Alveolar Process↗
PubMed1990

Histometric and ultrastructural studies of tissues surrounding Astra dental implants in dogs.

Twenty-four Astra titanium dental implants were inserted bilaterally, three on each side, into the mandibles of four dogs to study mucosal and bone-implant junctions. After a healing period of 6 months, the dogs were sacrificed and bone sections with implants were removed and processed for histologic evaluation. All implants were stable, and radiographs disclosed complete bone healing. The surrounding mucosa closely resembled that surrounding natural teeth. Histometric analysis of the alveolar bone revealed that, on average, 61.3% of the implant surface interface was integrated in the bone at the light-microscopic level.

Alveolar Process↗
PubMed1989

Cytotoxic and genotoxic effects of areca nut-related compounds in cultured human buccal epithelial cells.

Because betel quid chewing has been linked to the development of oral cancer, pathobiological effects of an aqueous areca nut extract, four areca nut alkaloids (arecoline, guvacoline, guvacine, and arecaidine), and four nitrosated derivatives [N-nitrosoguvacoline, N-nitrosoguvacine, 3-(N-nitrosomethylamino)propionaldehyde and 3-(N-nitrosomethylamino)propionitrile] have been investigated using cultured human buccal epithelial cells. Areca nut extract in a dose-dependent manner decreases cell survival, vital dye accumulation, and membrane integrity, and it causes formation of both DNA single strand breaks and DNA protein cross-links. Depletion of cellular free low-molecular-weight thiols also occurs, albeit at quite toxic concentrations. Comparisons of the areca nut-related N-nitroso compounds and their precursor alkaloids, at concentrations up to 5 mM, indicate that 3-(N-nitrosomethylamino)propionaldehyde is the most potent on a molar basis to decrease both survival and thiol content and to cause significant formation of DNA single strand breaks. Arecoline, guvacoline, or N-nitrosoguvacoline decreases survival and cellular thiols, whereas arecaidine, guvacine, N-nitrosoguvacine, and 3-(N-nitrosomethylamino)propionitrile have only minor effects on these variables. Taken together, the present studies indicate that aqueous extract and, in particular, one N-nitroso compound related to areca nut, i.e., 3-(N-nitrosomethylamino)propionaldehyde, are highly cytotoxic and genotoxic to cultured human buccal epithelial cells, of potential importance in the induction of tumors in betel quid chewers.

Arecoline↗
PubMed1988

Scanning electron microscopy of oral mucosa in vivo and in vitro: a review.

The oral mucosa is classified by function into lining, masticatory and specialized oral mucosa, with regional structural adaptation. In this review, the surface structures of the human oral mucosa have been studied in the scanning electron microscope (SEM). Regional variations in regard to keratinization, cell arrangements and microplications with related specific structures observed in SEM are described and correlated with the appearance of similar areas observed in the light microscope. Furthermore, human oral tissue and cell cultures have also been studied. These systems offer usable and complementary models for performing similar studies in vitro under controlled experimental conditions. We now show that explant cultures of human oral mucosa can propagate both normal epithelial cells and fibroblasts. The surface morphology of both cell types has been investigated in SEM.

Cells, Cultured↗
PubMed1987

Fixation and occurrence of dark and light cells in taste buds of fungiform papillae.

The fine structure of taste buds of the fungiform papillae of the Old World monkey Cynomolgus (Macaca fascicularis) was found to vary with the primary fixative solution used. Standard primary fixative solutions of glutaraldehyde as well as fixatives containing both formaldehyde and glutaraldehyde gave non-reproducible and usually poor results. Osmium tetroxide in distilled water gave reproducible fixation of acceptable quality. Further, when fixed in osmium tetroxide in distilled water, taste buds of the fungiform papillae did not show the dark and light cells well known from other studies. It is therefore suggested that the terms dark and light cells not be used as synonyms for receptor or support cells, since the appearance of taste bud cells is affected by fixation.

Animals↗
PubMed1987

Cytotoxic effects of cobalt-chromium alloys on fibroblasts derived from human gingiva.

The in vitro toxicity of 15 different cobalt-chromium alloys used in removable partial dentures and dental implants was studied. The composition of the alloys was determined by X-ray spectrometry. Alloys were tested on human oral fibroblasts in low density, semiconfluent or confluent cultures. The cultures were observed in a phase contrast microscope over a period of 3 wk. The alloys could be divided into three groups depending upon the degree of cell injury evoked. Group I alloys caused no cell injury. Group II alloys caused slight to moderate cell injury seen first after 3-7 days of exposure. Group III alloys caused severe cell injury with signs of cell damage detected after 12 h and total cell death after 3-14 days. The alloys' composition varied considerably with regard to cobalt, chromium and nickel as well as other components. Nevertheless, group II and III alloys had a higher nickel content than group I alloys in general.

Cells, Cultured↗
PubMed1985

Galvanic currents between dental alloys in vitro.

The galvanic current densities between gold, amalgam and cobalt-chromium, three different classes of dental alloys, were determined in vitro in artificial saliva kept at 35 degrees C. The maximum current density of 200 microA/dm2 was obtained between the conventional amalgam and a type III gold alloy. Galvanic currents of lesser magnitude could also be measured between amalgams high in copper and the other alloys. No measurable current densities were obtained between gold alloys and between gold and cobalt-chromium alloy with the exception of a casting and a solder gold alloy commonly used in combination.

Chromium Alloys↗
PubMed1981

Fine structure of taste buds in the human fungiform papilla.

The fine structure of taste buds on fungiform papillae from man was examined with particular reference to different cell types and to cell-nerve contacts. Most of the elongated cells of the taste bud extended from the basal lamina to the apical pore, terminating in irregular microvilli. The cells contained clear apical vesicles, mitochondria, filament bundles and Golgi cisternae. Unmyelinated nerve fibers, containing mitochondria as well as both dense-cored and clear synaptic-type vesicles, were scattered throughout the whole taste bud but were most numerous at the base. The nerve fibers were either in simple appositional contact or in mesaxonal contact with the taste bud cell. Typical synapses with the postsynaptic densities in the taste bud cell were sometimes seen. In addition, single taste bud cells were observed to have more than one type of contact with nerve fibers. As in the Old World monkey Cynomolgus it was not possible to distinguish different cell types described earlier in other species.

Adult↗
PubMed1981

Taste buds of the fungiform papillae in Cynomolgus monkey.

A study of the number of taste buds borne on 145 fungiform papillae from 20 Cynomolgus monkeys showed that, in contrast to the situation in man, most papillae are bud-bearing. The fine structure of taste buds on fungiform papillae of these monkeys was also examined. The cells contained clear apical vesicles, mitochondria, filament bundles and stacks of Golgi cisternae. Nerve fibres containing mitochondria, as well as clear and dense-cored vesicles, were scattered throughout the whole bud, but were more numerous near the base. It was, however, not possible to distinguish different cell types in these taste buds as a function of cell shape, electron density of the ground cytoplasm, presence of different organelles or relation to nerve processes.

Animals↗
PubMed1980

Human taste: response and taste bud number in fungiform papillae.

The number of basic taste qualities registered by single human fungiform papillae is correlated with the number of taste buds borne on these papillae. Multiple sensitivity was demonstrated both in single fungiform papillae and in single taste buds, with response to all four of the basic taste qualities occuring in a single taste bud.

Adolescent↗
PubMed1980

Effects of dental root posts on human gingival fibroblasts in vitro.

Dental root posts of gold-plated brass and German silver caused injury of human gingival fibroblasts in vitro. Posts made of stainless steel, titanium and gold alloys showed no discernible effects of cell morphology of apparent metabolic activity during the two-week period of observation.

Cells, Cultured↗
PubMed1979

Surface analysis of screwposts.

The content and distribution of metallic ions on the surface of gold-plated brass screwposts (Dentatus and MecOdont) were analyzed by X-ray microanalysis. On screwposts from one of the manufacturers the protective outer layer of gold was found to be localized to specific areas of the posts, i.e. the grooves, while unprotected Cu-Zn alloy was found on the ridges. The results are discussed with regard to results on root posts published earlier. Screwposts constructed in this way would appear to be of doubtful clinical value.

Copper↗
PubMed1979

Location and variation in number of taste buds in human fungiform papillae.

Serial sections of 182 fungiform papillae, obtained at autopsy from 22 individuals aged 2 days to 90 years, were examined by light microscopy with regard to location and number of taste buds. The taste buds were always found on the convex, dorsal surface of the papillae but otherwise failed to display any preferential location pattern. A total of 262 taste buds, an average of 1.4 per papilla, were found. However, there was considerable variation in the occurrence of taste buds, both from papilla to papilla and from case to case. While the number of taste buds in a single papilla varied from 0 to 27, 63% of the papillae had no taste buds at all, 26% had 1-3 buds and the remainder 4 or more buds. The mean number of taste buds per papilla varied from 0 to 9 between individuals; no dependence upon sex or age could be demonstrated for this variation. The significance of these anatomical findings with regard to physiological studies on taste involving the fungiform papillae is discussed.

Adolescent↗
PubMed1979

Autoradiographic study of distribution patterns of metals which occur as corrosion products from dental restorations.

Radioactive chromium, cobalt, gold and mercury, all of which may occur as corrosion products from dental restorations, were injected in single doses via the tail vein of mice and an in vivo analysis of their distribution was performed using whole-body autoradiography. Gold seemed to be inert and went mainly to the liver and bones. The other elements studied were distributed widely in the body and remained for a long period of time in specific target organs and tissues.

Animals↗
PubMed1978

Migration of metallic ions from screwposts into dentin and surrounding tissues.

Previous investigations have shown htat corrosion and other electrochemical processes occure when different alloys or metals are found together in the same mouth. In the present report, when teeth were restored using non-noble metallic posts, the metals diffused out to surrounding hard and soft connective tissues. The material consisted of extracted teeth with screw posts and surrounding discolored connective tissues. The screwposts had been cemented to the teeth 3--10 years earlier. The distribution of metal ions was determined by means of energy-dispersive X-ray microanalysis. Copper and zinc were found in both hard and soft tissues. Relatively high concentrations of copper ions were identified in areas of the teeth with blue-green discolorations. Zinc ions were detected in the dentin; they most probably originated from the screwposts and the cement, but zinc is also found in normal human dentin. Copper, zinc, silver and iron were found in the dark discolorations of the gingiva adjacent to the extracted teeth.

Connective Tissue↗