Histamine amplifies immune response of gingival fibroblasts.

Histamine is an important mediator in immune responses, but it is unclear whether periodontal tissues express histamine receptors and are able to respond to histamine. We hypothesized that histamine, inflammatory cytokines, and bacterial components released in inflamed periodontal tissues may be synergistically involved in periodontitis. The present study showed that human gingival fibroblasts mainly express histamine receptor H1R, and responded to histamine to produce interleukin (IL)-8. Stimulation of gingival fibroblasts with tumor necrosis factor-alpha, IL-1alpha, and lipopolysaccharide markedly induced IL-8 production, and the IL-8 production was synergistically augmented in the presence of or pre-treatment with histamine. Selective inhibitors of mitogen-activated protein kinases (MAPKs), nuclear factor (NF)-kappaB, and phospholipase C (PLC) significantly inhibited the synergistic effect. These results indicate that histamine induces IL-8 production from gingival fibroblasts through H1R, and synergistically augments the inflammatory stimuli by amplification of the MAPK and NF-kappaB through H1R-linked PLC. Abbreviations used: HDC, histidine decarboxylase; LPS, lipopolysaccharide; IL, interleukin; TNF, tumor necrosis factor; HR, histamine receptor; PLC, phospholipase C; MAPK, mitogen-activated protein kinase; NF, nuclear factor; ERK, extracellular signal-related kinase; JNK, c-Jun N-terminal kinase; R, receptor; TLR, Toll-like receptor; alpha-MEM, alpha-minimum essential medium; FCS, fetal calf serum; RT-PCR, reverse-transcriptase polymerase chain-reaction; ELISA, enzyme-linked immunosorbent assay; SD, standard deviation; LDH, lactate dehydrogenase.

Alveolar bone loss in rats infected with a strain of Prevotella intermedia and Fusobacterium nucleatum isolated from a child with prepubertal periodontitis.

Prevotella intermedia and fusobacterium nucleatum are associated with various forms of periodontal disease. The purpose of the present study was to infect the clinical isolates of these periodontopathic bacteria and to induce a significant loss of alveolar bone in specific pathogen-free (SPF) rats in the absence of ligatures. P. intermedia YKD8 and F. nucleatum YKZ5 were isolated from a prepubertal periodontitis patient, while P. gingivalis MWB13 was from a patient with juvenile periodontitis. At first, SPF Sprague-Dawley rats (70 days of age, male) were infected with A. viscosus Ny1R and subsequently superinfected with P. gingivalis MWB13, P. intermedia YKD8, or F. nucleatum YKZ5, respectively. The control group was infected with A. viscosus Ny1R alone. All rats were killed and periodontal bone levels were assessed morphometrically 135 days after the first infection with A. viscosus. P. intermedia YKD8 was recovered frequently from rats, with serum antibody levels remaining highly elevated throughout the experiment. Significant loss of alveolar bone was found in rats infected with P. intermedia YKD8, the virulence of which was equivalent to that of P. gingivalis MWB13. F. nucleatum YKZ5 also induced alveolar bone loss, but not significantly when compared with rats infected with A. viscosus Ny1R alone.

Tea catechins and related polyphenols as anti-cancer agents.

Epigallocatechin gallate (EGCg) and theaflavins, a major constituent of green tea infusion and the constituents of black tea, respectively, were found to inhibit matrix metalloproteinases (MMPs) which are intimately associated with tumor invasion and metastasis. EGCg and related polyphenols exhibited apoptosis-inducing activity for several cancer cell lines including human stomach and colon cancer cells. Comparison of the activity of these compounds revealed the importance of the number and the steric disposition of hydroxyl groups. A pyrogallol-type structure in a molecule is a minimum requirement for apoptosis induction of catechin compounds and that in the B ring has an important role in the activity. These data would provide useful information for designing anti-cancer agents on the basis of anti-inhibitory activity for MMPs and/or apoptosis-inducing activity.

Clinicopathological study of canine oral epulides.

To clarify the clinicopathological features of canine epulides, 189 epulides were reviewed retrospectively. The incidence of the fibromatous, ossifying, acanthomatous and giant cell epulides were 56.6% (107/189), 23.3% (44/189), 18.0% (34/189) and 2.1% (4/189), respectively. The average ages of dogs with fibromatous, ossifying, acanthomatous and giant cell epulides were 8.8, 8.4, 7.8 and 8.7 years, respectively. The male/female ratio of dogs with the acanthomatous epulis (0.8) was lower than those of dogs with the fibromatous (1.9), ossifying (1.4) and giant cell epulis (3.0). There were slight breed differences among the types of epulides. The most noticeable result was that 38.2% of the acanthomatous epulis occurred in Shetland sheepdogs. 43.9% of the fibromatous epulis and 52% of the ossifying epulides arose around maxillary premolars, while 58.8% of the acanthomatous epulis arose around the mandibular canines. Dogs with the fibromatous and ossifying epulides had more severe dental plaque deposition than those with the acanthomatous epulides. Few of the fibromatous (6/104) or ossifying epulides (4/44) showed recurrence after excision, while the majority (21/23) of the acanthomatous epulides showed rapid and repeated recurrences after surgical excision. Epulides treated with hemimandibulectomy or bleomycin chemotherapy did not recur. Giant cell epulides showed no recurrence after surgical removal. These results indicate that the acanthomatous epulis differed from other types of epulides in biological and morphological features and poor prognosis.

[Initial corrosion of dental casting alloys in the oral environment].

In order to study the initial corrosive changes of dental casting alloys in the mouth, the condition and composition of the proximal surface of the class II inlay were analyzed by the scanning electron microscope (SEM) and the electron probe microanalyser (EPMA). These analyses on the same small areas of the proximal surface were carried out every week for four weeks. The results were compared with the condition and composition of the preplacement in the mouth, and also with the data from former studies. 1. Changes observed in the 70Au-3Pt-3Pd-10Ag-14Cu alloy (Au-alloy) were slight in comparison to the other alloys in this experiment, both on the surface condition and composition. 2. The 12Au-45Ag-20Pd-18Cu alloy (Pd-alloy) appeared to be stable in the mouth, but the changes were greater than that of the Au-alloy. 3. The Au- and the Pd-alloys appeared to be stabler after hardening heat treatment. 4. The greatest change was observed in the 65Ag-22Sn-13Zn alloy. 5. Little change was found in the 72Ni-19Cr-6Si alloy by visual inspection, but the dendritic structure was observed by SEM. 6. Almost all these changes of the alloys in this study showed somewhat greater changes than those observed in the conventional basic immersion tests of alloys.

[Statistical survey of prosthetic restorations--outline and single crowns, cast cores and inlays].

This is a report on the statistical classification of the prosthetic restorations placed in out-patients of the Tokyo Medical and Dental University Hospital. The data were collected from the laboratory records during the period of January to June of 1986. The results are summarized as follows: 1. The total number of the prosthetic restorations placed in the outpatients were 7355, and 56% of these were covered by the health insurance. 2. Of the total restorations, 29.6% were cast cores, 18.2% were inlays and 17.2% were crowns. Post crowns, jacket crowns and partial veneer crowns were very few, being only 0.3%, 0.4% and 0.5%, respectively. 3. Approximately 50% of the prosthetic restorations were single crowns. 4. Compared to the record from about 20 years ago, the number as well as the ratio of the crowns including the facing crowns was approximately doubled. On the contrary, the number of jacket and post crowns has remarkably decreased. 5. With regard to the single anterior prosthetic restorations, the majority were the porcelain fused to metal crowns which were not popular 20 years ago.

Can brain impairment be detected by in utero behavioural patterns?

Fetal behavioural patterns were examined to test whether they could be used to localise sites of brain damage antenatally. Decreased fetal movement, persistent nonreactive fetal heart rate (FHR) pattern, and/or central nervous system malformation were used as indicators of possible neurological impairment. Ten fetuses tested in this way underwent further ultrasound examination observing movement of the extremities, chest wall (breathing), and eye and mouth, and active/quiet FHR patterns. Eight of these 10 fetuses were found on postnatal examination to have a brain impairment. The fetuses having potential in utero brain impairment were divided into four groups: those with (1) lesion sites at, or caudal to, the pons-medulla that were specifically identified by fetal behaviour, (2) diffuse lesions in the brain which, although resulting in abnormal behaviour, could not be localised by this behaviour, (3) lesions localised in the cerebral hemisphere(s) but with no abnormal behaviour and (4) temporally abnormal behaviour in utero, finally changing over to a normal pattern with no neonatal neurological abnormality. A screening system for the antenatal assessment of brain impairment is thus proposed.

Reduction of dental plaque deposition in humans by oolong tea extract.

The inhibitory effect of oolong tea extract (OTE) containing polymerized polyphenols on plaque deposition was examined in 35 human volunteers. Thirty-five human volunteers, aged 18-29 years, who received extensive oral prophylactic procedures were requested to refrain from all oral hygiene procedures for 4 days, and to rinse their mouth with 0.5 mg/ml OTE solution in 0.2% ethanol before and after every intake of food and before sleeping at night. No restriction regarding meals was given during the test period, except to refrain from teas or coffee. Plaque deposition was evaluated after disclosing the teeth with Erythrocin at the termination of this experiment. The study was repeated 1 week after the first trial, but only 0.2% ethanol without OTE was used for mouthrinsing in the second trial. OTE was found to significantly inhibit plaque deposition in volunteers, although mouthrinsing with OTE solution had no significant effect on the number of mutans streptococci in unstimulated whole saliva.

Noncariogenicity of maltitol in specific pathogen-free rats infected with mutans streptococci.

The effect of maltitol on caries development was examined in an experimental caries system employing specific pathogen-free (SPF) Sprague-Dawley rats. Fourteen strains of oral streptococci, including mutans streptococci, did not utilize the maltitol nor produce sufficient acid to demineralize tooth enamel. Furthermore, maltitol did not serve as a substrate for glucosyltransferases of either Streptococcus mutans MT8148R or Streptococcus sobrinus 6715 to synthesize water-insoluble glucan. Maltitol induced no significant dental caries in SPF rats infected with these mutans streptococci, and replacement of the dietary sucrose content with maltitol resulted in a trend towards caries reduction in SPF rats.

[Non-cariogenicity of maltitol in vitro and animal experiments].

The caries inducing activity of maltitol was examined in in vitro and animal experiments. Fifteen strains of oral streptococci were not able to ferment maltitol. Also, maltitol inhibited the glucan synthesis from sucrose by GTases from mutans streptococci. However, the inhibition of growing-cell adherence was not so marked with the addition of maltitol to sucrose culture. In the animal experiments, maltitol did not induced dental caries in rats infected with mutans streptococci. Furthermore, maltitol significantly inhibited the sucrose-induced dental caries in rats infected with S. sobrinus 6715. However, there was no significant difference in rats infected with S. mutans MT8148R. These results indicated that maltitol is useful as a non-cariogenic sucrose substitute.

Trehalulose does not induce dental caries in rats infected with mutans streptococci.

The effects of trehalulose, a structural isomer of sucrose, and a syrup (TP syrup) rich in trehalulose and palatinose on caries development were examined in specific pathogen-free Sprague-Dawley rats. Streptococcus mutans MT8148R and Streptococcus sobrinus 6715 fermented the syrup which resulted in acid production, while both strains were found not to utilize trehalulose. Furthermore, trehalulose did not serve as a substrate for glucosyltransferases of these mutans streptococci to synthesize water-insoluble glucan, and it inhibited the sucrose-dependent adherence of mutans streptococci to a glass surface. Although trehalulose induced no significant dental caries in specific pathogen-free rats infected with either MT8148R or 6715, TP syrup was found to induce significant but low dental caries. Furthermore, replacement of the dietary sucrose content with trehalulose resulted in a significant reduction of caries development in rats infected with strain 6715.

[Caries-inducing activity of soybean-oligosaccharide (SOR) in vitro and in experimental dental caries of rats].

The caries-inducing activity of soybean-oligosaccharide (SOR: stachyose- and raffinose-rich sugar mixture) was examined in in vitro and in vivo experiments. Streptococcus mutans MT 8148R fermented SOR and produced acids. However Streptococcus sobrinus 6715 did not ferment. SOR was not able to act as a substrate for crude glucosyltransferases (GTase) of these mutans streptococci to synthesize the water-insoluble glucan. However, SOR did not inhibit the synthesis of water-insoluble glucan from sucrose by crude GTase. SOR was proved to be of low cariogenicity in rats infected with S. sobrinus 6715.

Oral passive immunization against dental caries in rats by use of hen egg yolk antibodies specific for cell-associated glucosyltransferase of Streptococcus mutans.

The effect of polyclonal egg yolk immunoglobulin G antibodies (yIgG) raised against whole cells, cell-free (CF) glucosyltransferase (GTase), or cell-associated (CA) GTase of serotype c Streptococcus mutans was examined in terms of in vitro inhibition of virulence-related factors of S. mutans and protection of S. mutans-infected rats against the development of dental caries. Hens (18 weeks old) were immunized with formalin-treated whole cells, purified CF-GTase, or CA-GTase together with Freund's complete adjuvant. In addition, yIgG to surface protein antigen was used in some in vitro experiments for comparison with other antibodies. yIgG was purified by ammonium sulfate precipitation followed by DEAE-Sephacel column chromatography or fractional precipitation with ethanol. Purified yIgG was found to be a 220-kDa protein, which was dissociated into heavy and light chains upon addition of 2-mercaptoethanol. yIgG to whole cells and surface protein antigen gave a heavy aggregation of S. mutans organisms, while yIgG to CF- and CA-GTase specifically inhibited the enzymatic activity of the respective GTase. yIgG to CA-GTase and whole cells was found to clearly suppress the adherence of S. mutans cells to a glass surface. Specific-pathogen-free Sprague-Dawley rats that had been infected heavily and repeatedly with S. mutans and fed diet no. 2000 developed severe dental caries, while rats fed diet 2000 containing greater than or equal to 0.1% yIgG to CA-GTase showed a statistically significant reduction in dental plaque accumulation and caries development. Administration of yIgG to CF-GTase and whole cells failed to protect against caries. These results clearly suggest that yIgG to S. mutants CA-GTase specifically inhibited a virulence factor of this organism, i.e., insoluble glucan-synthesizing CA-GTase, resulting in a significant reduction in the development of dental caries.

Inhibitory effects of oolong tea extract on caries-inducing properties of mutans streptococci.

The inhibitory effects of oolong tea extract (OTE) on the caries-inducing properties of mutans streptococci were examined in vitro. OTE reduced the rate of acid production by mutans streptococci accompanied with the retardation of growth rate of mutans streptococci, while the action by chromatographically isolated oolong tea polyphenol (OTF6) was weak. On the other hand, both oolong tea products decreased cell surface hydrophobicity of almost all the oral streptococci examined in the present study, and also induced cellular aggregation of Streptococcus mutans, Streptococcus oralis, Streptococcus sanguis or Streptococcus gordonii. In these reactions, OTF6 showed a more pronounced activity than OTE. Furthermore, the oolong tea products inhibited the adherence of mutans streptococci to saliva-coated hydroxyapatite. These results suggest that OTF6 may inhibit bacterial adherence to the tooth surfaces by reducing the hydrophobicity of mutans streptococci, and OTE may inhibit caries-inducing activity of mutans streptococci by reducing the rate of acid production.

Intravascular oxygen monitoring with a polarographic oxygen cathode.

Thin flexible oxygen cathodes coated with heparin-dispersed cellulose diacetate were prepared for an intravascular monitoring of blood pO2. The effect of the thickness of cellulose diacetate on various characteristics of the cathode, such as its sensitivity, response, residual current, moving artefact, linearity, and protection against poisoning, were measured. Coating with six to ten layers of 7.5% cellulose diacetate resulted in a high level of protection for cathode against poisoning by blood constituents, while still leaving a sufficiently rapid response. An instillation system using heparinized saline has been designed for further prevention of local blood coagulation. At the same time this system maintains a stable conductance of the salt bridge and furthermore, enables in vivo calibration of the cathode sensitivity by supplying an instillation solution of a known oxygen tension. Using this electrode system, various intravascular pO2 measurements have been carried out, and one representative result is shown. The advantages and disadvantages of this type of separated electrode system compared with the combined type electrode are also discussed in detail.

Comparison of the cariostatic effects between regimens to administer oolong tea polyphenols in SPF rats.

The cariostatic effect of oolong tea polyphenols administered according to several regimens was examined in specific pathogen-free (SPF) Sprague-Dawley rats given both a diet containing 20% sucrose and infected with S. sobrinus 6715. The crude preparation (OTE) of oolong tea polyphenols showed the most prominent effect on caries reduction in SPF rats when OTE was administered in the drinking water beginning 1 day prior to the inoculation of S. sobrinus 6715, when compared with chromatographically isolated polyphenol fractions (OTF1 and OTF6) of OTE. Reduction in caries development was found even when OTE was given 1 day after inoculation of the organism. OTE was shown to significantly inhibit dental caries in rats at the concentrations of either more than 5 microg/ml in drinking water or more than 10 microg/g in diet. OTF1 and OTF6 also showed significant inhibition of caries induction, with the minimum inhibitory concentration of OTF6 being 50 microg/ml in drinking water and the minimum inhibitory concentration of OTF1 being 100 microg/g in diet. These results indicate that cariostatic activity of OTE was effective even after the establishment of S. sobrinus in the oral cavity and was more effective in drinking water than in diet. Furthermore, OTE may contain some anticaries substances that affect the virulence of S. sobrinus other than glucosyltransferases.

Oolong tea polyphenols inhibit experimental dental caries in SPF rats infected with mutans streptococci.

An extract of oolong tea (semifermented tea leaves of Camellia sinensis) and its chromatographically isolated polyphenolic compound was examined for in vitro inhibitory effects on glucosyltransferases (GTases) of mutans streptococci and on caries development in Sprague-Dawley rats infected with mutans streptococci. The samples showed no detectable effect on the growth of mutans streptococci. However, insoluble glucan synthesis from sucrose by the GTases of Streptococcus mutans MT8148R and Streptococcus sobrinus 6715 was markedly inhibited, as was sucrose-dependent cell adherence of these mutans streptococci. The administration of the oolong tea extract and the isolated polyphenol compound into diet 2000 and drinking water resulted in significant reductions in caries development and plaque accumulation in the rats infected with mutans streptococci. The active components in the oolong tea extract were presumptively identified as polymeric polyphenols which were specific for oolong tea leaves. These results indicate that the oolong tea polyphenolic compounds could be useful for controlling dental caries.

[Caries-inducing activity of isomaltooligosugar (IMOS) in in vitro and rat experiments].

The caries-inducing activity of Isomaltooligosugar (IMOS: a isomaltose rich sugar mixture) was examined in in vitro and in vivo experiments. Strains of Streptococcus mutans MT8148R and Streptococcus sobrinus 6715 fermented IMOS and produced acids. IMOS inhibited the glucan synthesis from sucrose by glucosyltransferases from both of S. mutans and S. sobrinus. Furthermore, IMOS inhibited sucrose-dependent adherence of those mutans streptococci. IMOS was found to induce significant but minimal caries SPF Sprague-Dawley rats infected with either MT8148R and 6715. However, IMOS did not inhibit the caries which was induced by sucrose.