Biomedical subjects

S Sobue

Publications and source records attributed to S Sobue.

At least 55 records · Page 3Linked to original sources

PubMed1992

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.

Animals↗

PubMed1992

Effects of hyposalivation on the oral microflora of rats fed sucrose or wheat flour diets.

The effects of hyposalivation on the induction of dental caries and on the composition of the oral microflora were examined in specific pathogen-free Sprague-Dawley rats fed either a sucrose or a wheat flour diet with or without inoculation of Streptococcus mutans. Significant dental caries was induced in hyposalivated rats fed diet 2000 containing 56% sucrose, irrespective of infection by S. mutans. Diets containing 56% wheat flour did not induce dental caries in either hyposalivated or sham-operated rats, irrespective of infection by S. mutans. Bacteriological examinations at the end of the experiment demonstrated that the total numbers of lactobacilli and staphylococci increased in hyposalivated rats irrespective of the diet given, while the inoculated stain of S. mutans decreased significantly in hyposalivated rats. These findings suggest that some acidogenic microorganisms such as lactobacilli and staphylococci that can utilize sucrose or glucose but not wheat flour may also promote dental caries in hyposalivated rats.

Animals↗

PubMed1992

The occurrence of interglobular dentin in incisors of hypophosphatemic mice fed a high-calcium and high-phosphate diet.

The incisor dentin of hypophosphatemic (Hyp) mice was examined histopathologically to determine whether the multiple occurrences of interglobular dentin would be influenced by the serum phosphate level. Both normal and Hyp mice (12 weeks of age) were divided into two groups. The mice in one group were given a control diet (1.42% Ca, 1.16% P) and the other a high-calcium and high-phosphate diet (2.00% Ca, 3.00% P) for 30 days. Blood was collected from the mice every fifth day for measurement of the calcium and phosphate concentrations in serum. Both ground and decalcified cross-sections were prepared from incisors from the mandible and maxilla for microscopic examination. The levels of serum Ca and P were almost constant in normal mice, regardless of diet. On the other hand, serum P levels in Hyp mice fed the control diet were significantly lower than those in normal mice. The ten days' feeding of the high-Ca/-P diet significantly elevated the serum P level in Hyp mice, and it reached a level similar to that of the normal mice. However, histopathological examination showed no significant changes in incisor dentin of Hyp mice fed the high-Ca/-P diet, and interglobular dentin still occurred. These results suggest that the multiple formations of interglobular dentin, which is the most outstanding feature of X-linked hypophosphatemic vitamin-D-resistant rickets, are not influenced in Hyp mice by the short-time normalization of the serum phosphate level.

Animals↗

PubMed1991

Dental caries induction in hyposalivated rats.

The effects of hyposalivation on the induction of dental caries and on the oral microflora were examined in SPF Sprague-Dawley rats with or without inoculation of oral streptococci. Significant dental caries was induced in hyposalivated rats, irrespective of the infection with oral streptococci including Streptococcus mutans. In addition, bacteriological analyses demonstrated that the total number of lactobacilli increased significantly at the expense of the inoculated streptococci. These findings suggest that opportunistic infections may be induced in the oral cavity of hyposalivated rats and some acidogenic microorganisms including lactobacilli may promote the induction of dental caries.

Animals↗

PubMed1991

[A case of a calcifying odontogenic cyst associated with odontoma inducing impaction of a deciduous tooth].

A 4-year-old boy was examined with a chief complaint of "Delayed eruption of maxillary right deciduous central incisor". Oral examination revealed a firm swelling on the labial gingiva at the right deciduous incisor of maxilla. Radiographic examination revealed that odontoma-like substances disturbed the eruption of the central deciduous maxillary incisor. The odontoma-like substances were removed surgically and examined histopathologically. The thin sections showed findings typical of a Calcifying Odontogenic Cyst with Odontoma.

Child, Preschool↗

PubMed1991

[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.

Animals↗

PubMed1991

[Cyclosporin-A induced gingival overgrowth--strain differences in the rats].

Cyclosporin-A (CsA) which is an effective immunosuppressive agent to control the rejection of organ transplants causes gingival overgrowth as one of accompanying side effects. However, the mechanism of this particular gingival overgrowth still remains unclear. This seems to be largely due to the difficulty of reproducing gingival overgrowth in experimental animals, especially in rodents. The purpose of the present study was to establish a rat model for CsA-induced gingival overgrowth. Specific pathogen-free Fischer and Sprague-Dawley rats (20 days old) were used and fed a caries inducing diet containing CsA. The degree of gingival overgrowth was measured, and histological examination of the gingival sections was performed. The results obtained were as follows; 1. Marked gingival overgrowth was noted around mandibular molars of all rats fed died 2000 containing 56% sucrose supplemented with CsA (a diet of 120-200 mg/kg). This overgrowth was more conspicuous in buccal than in lingual gingiva. However, there were no differences between the two strains of rat in the macroscopic findings as well as in the severity of CsA-induced gingival overgrowth. 2. Rats receiving CsA treatment for 40 days (at 63 days of age) showed the maximum level of gingival overgrowth in both strains of rats. When the gingival sulcus depths at 48 days of age were compared, the S.D. rats seemed to be a higher responder to CsA than the Fischer rats. 3. CsA treated rats showed significantly higher plaque scores than untreated rats. However, CsA-induced gingival overgrowth was little affected by this enhancement of plaque accumulation in the rats infected with S. sobrinus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Phenytoin-induced gingival overgrowth in rats infected with Streptococcus sobrinus 6715.

Inbred Fischer rats were fed a high sucrose diet (No. 2000) containing phenytoin (5,5-diphenyl-hydantoin) for 52 days, which produced serum and salivary PHT levels of 13-14 and 2.6-2.7 micrograms/ml, respectively. Gingival overgrowth was induced in the molar region of all PHT-treated rats but was more severe in Streptococcus sobrinus 6715-infected rats than in non-infected rats, which had lower plaque scores. No significant overgrowth was found in rats infected with Strep. sobrinus and fed the same diet without PHT. Thus dental plaque accumulation enhanced, but was not essential for the development of the PHT-induced gingival overgrowth. Histological examination showed that the density of fibroblasts and connective tissue fibres was similar in all groups. This experimental model could serve as a useful means of understanding the pathogenesis of PHT-induced gingival overgrowth.

Animals↗

PubMed1990

Gingival overgrowth induced by cyclosporin A in rats.

Gingival overgrowth, which is one of the major side-effects of this immunosuppressive agent, was studied in specific pathogen-free Fischer rats fed diet No. 2000 containing 56% sucrose. Marked macroscopic overgrowth was noted in mandibular gingiva of all the rats fed this diet containing cyclosporin A. The overgrowth was more severe in buccal than in lingual gingiva. Rats fed the cyclosporin-containing diet and infected with Streptococcus sobrinus 6715 had the most gingival overgrowth. Histopathological examination revealed that the bulk of the enlargement consisted of fibrous connective tissue without a marked increase in the number of fibroblasts or inflammatory cells.

Animals↗

PubMed1990

Chemical, immunobiological and antigenic characterizations of lipopolysaccharides from Bacteroides gingivalis strains.

Lipopolysaccharides (LPS) were extracted from whole cells of seven strains of Bacteroides gingivalis--381, ATCC 33277, BH18/10, OMZ314, OMZ406, 6/26 and HW24D-1--by the phenol/water procedure, and purified by treatment with nuclease and by repeated ultracentrifugation. These LPS were composed of hexoses, hexosamines, fatty acids, phosphorus and phosphorylated 2-keto-3-deoxyoctonate (KDO). The major components of the lipid portion of these LPS were hexadecanoic, 3-hydroxyhexadecanoic, branched 3-hydroxypentadecanoic and branched 3-hydroxyheptadecanoic acids. All the LPS preparations induced marked mitogenic and in vitro polyclonal B cell activation responses in spleen cells from both C3H/HeN and C3H/HeJ mice, exhibited no definitive preparatory activity in the local Shwartzman reaction in rabbits, but were active in the chromogenic Limulus amoebocyte lysate test. A monoclonal antibody (mAb) raised against the LPS from B. gingivalis strain 6/26 reacted with LPS from all other B. gingivalis strains tested. Other mAbs raised against LPS from B. gingivalis strains 381 and 6/26 reacted with the LPS from strains 381, ATCC 33277, BH18/10 and 6/26 (these strains were termed LPS serogroup I), as revealed by ELISA and immunodiffusion. The LPS from these strains except for 6/26 showed almost identical patterns in SDS-PAGE stained with ammoniacal silver. A mAb raised against the LPS from B. gingivalis HW24D-1 reacted with the LPS from strains OMZ314, HW24D-1 and OMZ409 (LPS serogroup II). These LPS, except OMZ409, exhibited very similar profiles in SDS-PAGE. These results indicate that there are at least two different antigenic groups present among LPS from B. gingivalis strains, as well as a common, species-specific antigen.

Animals↗

PubMed1990

Plaque formation of dietary isomaltulose in humans.

The plaque formation of isomaltulose, a sucrose isomer, was examined in 15 human volunteers with both diet and oral hygiene under supervision. The subjects were requested to refrain from all oral hygiene procedures for 3 days and were provided between-meal snacks containing 157 g of 4 test sugars (100% isomaltulose, 70% isomaltulose + 30% sucrose, 50% isomaltulose + 50% sucrose, and 100% sucrose). The study was repeated 4 times over 4 weeks. The isomaltulose diet resulted in the lowest plaque index, while sucrose induced a significantly greater deposition. In the absence of sucrose-containing snacks, mutans streptococci in saliva decreased below the baseline level. These results suggest that isomaltulose may be a suitable substitute for sucrose in between meal snacks.

Adult↗

PubMed1990

[Inhibitory effects of a hot water extract from Japanese tea on the cell growth of mutans streptococci].

This study was undertaken to examine the effect of a hot water extract from Japanese tea on the cellular growth of mutans streptococci in vitro. The extract contained polyphenol compounds, mainly catechin derivatives. Few fluoride components were contained in the extract. Streptococcus mutans MT8148R (serotype c) and S. sobrinus MT6715 (serotype g) strains were used in the present study. The organisms (10-10(7) CFU/ml) were cultured in brain heart infusion (BHI) and tryptose phosphate (TP) broths containing the tea extract (0-8 mg/ml). After incubation for 24-48 hours the cell numbers in the cultures were determined. Furthermore, cell growth of these strains on BHI agar plates containing the extract (0-2 mg/ml) were examined. The results obtained were as follows: 1. The tea extract (2-8 mg/ml) in BHI broth inhibited remarkably the growth of S. mutans and S. sobrinus (inoculum size; 10(6) CFU/ml). No difference in susceptibility to the tea extract between S. mutans and S. sobrinus was noted. 2. The cell growth of both strains in TP broth was inhibited by the tea extract. However S. sobrinus was found to be more sensitive to the extract than S. mutans. 3. Growth of S. sobrinus cells on the BHI agar plate was suppressed by the tea extract more effectively than that of S. mutans. These results suggest that the tea extract would be useful as an anti-cariogenic agent.

Catechin↗

PubMed1990

Complete root resorption of an upper central incisor due to ectopic eruption of canine in a deaf-mute child.

Unilateral complete root resorption of the permanent central incisor was experienced in a boy with deaf and dumb. Transposition of tooth germ or abnormally directed eruption of the canine caused not only an entire root but a part of enamel resorption. The patient was diagnosed clinically and radiographically as an ectopic eruption of the right maxillary upper canine and then treatments were provided to improve esthetic and functional conditions in terms of eruption guidance. It should be emphasized that the early diagnosis and the subsequent eruption guidance is essential in the patient with these kinds of eruption disorder of the mixed dentition.

Adolescent↗

PubMed1989

The crystallinity of human deciduous teeth in hypophosphataemic vitamin D-resistant rickets.

Five teeth were obtained from three patients with hypophosphataemic vitamin D-resistant rickets (HVDRR) and five corresponding sound teeth from five healthy children. According to powder X-ray diffraction analysis, the half-peak breadths of (310) and (002) reflections of HVDRR dentine were smaller than those of normal dentine. Splitting fractions obtained from i.r. spectral analysis of HVDRR dentine powder were larger than those of normal. Microbeam X-ray diffraction analysis showed that the relative half-peak breadths of globular dentine in ground sections of HVDRR teeth were smaller than those of normal circumpulpal dentine. Transmission electron microscopy demonstrated that the hydroxyapatite crystals of globular dentine in HVDRR teeth were larger than those of normal dentine. Thus the crystallinity of deciduous tooth dentine in HVDRR was greater than that of normal dentine, mainly because of the large hydroxyapatite crystals in HVDRR globular dentine.

Child↗

PubMed1989

Orofacial manifestations in a child with Fanconi's syndrome.

Orofacial and dental findings in a child with Fanconi's syndrome and accompanying glycogen storage disease are presented. Remarkable retardation of skeletal growth, resulting in dwarfism, was noted. Cephalometric analyses revealed that the size of the patient's craniofacial bones at 10 years of age was as small as that of the average 4-year-old child. Development of the permanent dentition was retarded for 3 to 4 years. Histologic examination of an exfoliated primary canine showed hypomineralization of the dentin structure.

Cephalometry↗

PubMed1989

Effect of a bacteriocin-producing strain of Streptococcus sobrinus on infection and establishment of Streptococcus mutans on tooth surfaces in rats.

The effect of bacteriocin produced by Streptococcus sobrinus MT6223 on infection and establishment of Streptococcus mutans MT6222 was studied in specific pathogen-free rats. These strains were isolated from a carious lesion of a single subject. S. mutans MT6222 was found to be susceptible to the growth inhibitory action of S. sobrinus MT6223. When simultaneously inoculated into the oral cavity of rats, even a small inoculum (10(5) CFU) of S. sobrinus MT6223 completely inhibited colonization of S. mutans MT6222 on the tooth surface. Also, S. sobrinus MT6223 eliminated S. mutans MT6222 when MT6223 (10(8) CFU) was inoculated 2 days after the inoculation of 10(8) CFU cells of MT6222. Similar results were obtained in dental plaque samples from the tooth surface and the fissures of the upper molars at the end of the experiment. However, when S. sobrinus MT6223 (10(8) CFU) was inoculated 2 weeks after the inoculation of S. mutans MT6222 (10(8) CFU), MT6223 coexisted with MT6222. However, the plaque samples showed that MT6223 inhibited the establishment of MT6222 on smooth surfaces, but not in fissures. In addition, MT6223 protected against subsequent infection with MT6222. However, a nonbacteriocinogenic mutant of S. sobrinus MT6223 did not inhibit the infection and establishment of S. mutans MT6222.

Animals↗

PubMed1989

Vertical crown-root fracture of the mandibular first primary molar in a one-year-old child.

A vertical crown-root fracture of the mandibular first primary molar in a 21-month-old child is presented. The mandibular primary first molar was fractured vertically and split into 2 pieces. The tooth fracture had not been noticed for about 5 months after the accident, and the tooth was left without any treatment. The pulp tissue of the mesial root maintained its vitality, but the distal root was nonvital.

Humans↗

PubMed1989

Microscopic and crystallographic examinations of the teeth of the X-linked hypophosphatemic mouse.

Teeth from the C57BL/6J-Hyp mouse (Hyp mouse) were examined histologically, radiographically, and crystallographically. Microscopic examinations of the ground sections, the decalcified and H-E-stained sections, and the contact microradiograms of molars and incisors from the Hyp mouse showed several abnormalities--such as large pulp chamber, wide predentin, thin dentin at the pulp floor, and multiple occurrences of interglobular dentin. Powder and microbeam x-ray diffraction analyses showed that the crystallinity of hydroxyapatite in incisor globular dentin from the Hyp mouse was higher than that in incisor dentin from the normal mouse. On the other hand, the findings of transmission electron microscopy demonstrated that the sizes of hydroxyapatite crystals of globular dentin in the Hyp incisor were larger than those in normal incisor dentin. These results demonstrated that the findings in Hyp mouse teeth were in accord with those of human XLH teeth.

Animals↗