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Biomedical subjects

I Morisaki

Publications and source records attributed to I Morisaki.

At least 19 recordsLinked to original sources
PubMed1995

Clinical, microbiological and host defense parameters associated with a case of localized prepubertal periodontitis.

A 4-year-old Japanese boy was referred to Osaka University Dental Hospital because of severe mobility and pain of the right lower primary canine. The canine had severe bone loss and a pocket depth exceeding 5-6 mm. The left lower canine showed slight mobility and moderate alveolar bone loss. The other primary teeth showed no pathogenic findings. The subgingival microflora from the right lower canine was dominated by gram-negative rods, especially capnocytophaga and fusobacterium, while actinomyces sp. were the most common gram-positive bacteria. While neutrophil functions of the patient were within the normal ranges of healthy subjects, some lymphocyte functions such as IL-2 production and IgG and IgM syntheses were lower in the patient. 7 months after the extraction of the right lower primary canine, the patient complained of pain around the right lower primary lateral incisor. In 3-4 weeks, the alveolar bone was lost rapidly and mobility of the lower anterior teeth increased significantly. The primary lateral incisor was extracted and the other primary teeth were treated by sealing and systemic and local administration of antibiotics. After treatment, the lower anterior teeth became less mobile and the gram-positive cocci predominated.

Actinomyces↗
PubMed1995

Factors influencing nifedipine-induced gingival overgrowth in rats.

Factors such as age, the dose of nifedipine administered in the diet, serum drug level, duration of drug administration, and sex which may influence nifedipine-induced gingival overgrowth were examined in a rat model using 20-, 50-, and 90-days-old male and female rats. Oral administration of nifedipine (50 to 250 mg/kg diet) increased the serum level of the drug in a dose-dependent manner in both males and females. However, a higher serum level was required in females than males to attain the same degree of gingival overgrowth. The minimum dietary concentrations of the drug required to elicit gingival overgrowth in males and females were 150 and 100 mg/kg, respectively, which gave respective minimum serum levels of 800 and 1100 ng/ml. The degree of overgrowth depended on the serum concentration of the drug after it had reached the required minimum in male and female animals. Administration of nifedipine (250 mg/kg diet) for 20 days was enough to induce maximal overgrowth, but this induction occurred only in rats that started to receive the drug when they were 20 days old, not in those that started at 50 and 90 days of age for the same administration period of 55 days, and the overgrowth regressed and the gingiva were normal 40 days after ceasing drug administration. These results suggest that gingival overgrowth occurred in accordance with the drug concentration in the diet, as well as that in the serum, and was more likely to occur in males and younger individuals.

Age Factors↗
PubMed1992

Latex agglutination test for detection of mutans streptococci in relation to dental caries in children.

A simple and rapid system based on a latex agglutination (LA) reaction was devised for the detection of mutans streptococci in dental plaque. Latex particles were sensitized with antibodies against whole cells of Streptococcus mutans strains MT8148 (serotype c), MT703R (e) and OMZ175 (f) and Strep. sobrinus strains B13 (d) and 6715 (g). These sensitized particles were agglutinated within a few minutes after addition of 1.0-10 ng serotype-specific antigen from the homologous organisms or the nitrous acid extract of whole cells at 10(5)-10(6) c.f.u. The LA test specifically differentiated not only mutans streptococci from the other oral streptococci but also Strep. sobrinus from Strep. mutans. The LA test was also applicable to extracts of plaque from 206 human subjects who harboured mutans streptococci. In clinical trials, the outcome of the LA test correlated significantly with the number of mutans streptococci found in plaque (p less than 0.0001), which was quantified by the selective cultivation of mutans streptococci. Furthermore, the LA test discriminated between Strep. mutans and Strep. sobrinus from human dental plaque. The sensitivity and the specificity of the LA test for detection of mutans streptococci were 78.9 and 100%. The degree of reactivity in the LA test correlated significantly with the number of decayed tooth surfaces (p less than 0.0001) and decayed and filled tooth surfaces (p less than 0.0001). These results suggest that the LA test could be useful clinically for the detection of mutans streptococci in dental plaque as well as serving as a caries-activity test.

Antibodies, Bacterial↗
PubMed1992

Purification and properties of extracellular mutacin, a bacteriocin from Streptococcus sobrinus.

Mutacin MT6223, a cell-free bacteriocin produced by Streptococcus sobrinus MT6223, was purified by ammonium sulphate precipitation, chromatofocusing with PBE 94 and column chromatography on SP Sephadex C-25. The specific activity of the purified mutacin was increased 1950-fold with a recovery of 9.7%. The molecular mass of the purified mutacin preparation was estimated to be 6.5 kDa. The mutacin activity was stable from pH 2-7, and was resistant to treatment at 100 degrees C for 20 min. It was inactivated by papain or ficin digestion, and was partially inhibited by alpha-chymotrypsin. The mutacin was found to be active against strains of serotypes c, e and f of Streptococcus mutans and the addition of purified mutacin MT6223 to growing cells of S. mutans MT8148 resulted in a rapid inhibition of incorporation of [3H]thymidine, [3H]uracil or L-[3H]glutamic acid into DNA, RNA or protein, respectively. Specific pathogen-free Fischer rats fed diet 2000 and infected with S. mutans MT8148R showed significantly fewer caries and lower plaque scores when mutacin was administered through drinking water. The present study demonstrates that mutacin MT6223 inhibited the growth of mutans streptococci. Thus, mutacin MT6223 may be a candidate for use in dental caries prevention.

Animals↗
PubMed1991

Induction of interleukin-1 and -6 in human gingival fibroblast cultures stimulated with Bacteroides lipopolysaccharides.

Normal human gingival fibroblasts stimulated in vitro by lipopolysaccharides (LPS) from oral Bacteroides species produced cell-free and cell-associated thymocyte-activating factors (TAF). Neutralization assays using antisera to human interleukin-1 alpha (HuIL-1 alpha), HuIL-1 beta, and HuIL-6 revealed that cell-free TAF was attributable mainly to IL-1 beta and that IL-6 augmented the TAF activity of IL-1 beta in the culture supernatant. Another factor(s), however, may also be involved in cell-free TAF. By contrast, the active entity of cell-associated TAF was ascribed to IL-1 alpha alone. Furthermore, IL-6 was detected mainly in the supernatant of fibroblast cultures stimulated with Bacteroides LPS. Fibroblasts pretreated with natural human beta or gamma interferon, but not those pretreated with alpha interferon, synthesized higher levels of cell-associated IL-1 alpha in response to stimulation by Bacteroides LPS; however, no interferons exhibited direct IL-1-inducing activity or synergistic IL-1-inducing activity with LPS. Endogenously induced beta interferon was suggested to be necessary for fibroblasts to produce cell-associated IL-1 alpha in response to Bacteroides LPS.

Antigens, Differentiation, T-Lymphocyte↗
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

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

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

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

[Changes of antibody and splenic plaque forming cell responses to mutans streptococci in the rats infected with S. sobrinus 6715].

The study was undertaken to examine the changes in humoral IgM, IgG and IgA antibodies and splenic plaque forming cell responses against Streptococcus sobrinus 6715 in rats infected with the same mutans streptococci. The serum samples were collected every week for 24 weeks after infection (20 day old, Sprague Dawley rats). Humoral anti-S. sobrinus 6715 IgG and IgA antibodies were determined by an enzyme-linked immunosorbent assay. In the separate experiment, rat splenic IgM, IgG and IgA anti-trinitrophenyl (TNP) conjugated S. sobrinus plaque-forming cell (PFC) responses were also determined from 1 to 12 weeks after the infection. The results obtained were as follows: 1. From 1 to 4 weeks after infection, a slight increase in serum IgG anti-S. sobrinus antibody response was observed in the group of rats infected with S. sobrinus 6715 when compared with the non-infected rat group. However, beyond the 5th week, there was no difference in serum antibody responses between these two groups. 2. Infected rats showed a 2-9 times higher serum anti-S. sobrinus IgA antibody response than those of uninfected rats for 6 weeks after the infection. After this period just as with the IgG response, no difference in the IgA titers was found between these two groups. 3. Splenic IgM, IgG and IgA anti-TNP-S. sobrinus PFC responses showed a remarkable decrease shortly after the infection. These results suggest that the infected rats would gradually acquire oral tolerance to S. sobrinus antigen after the infection.

Animals↗
PubMed1987

Corneal test as a reliable method for detection of the delayed-type hypersensitivity reaction in mice.

Antigen solution could be injected into the cornea of sensitized mice using a fine needle and a stereoscopic dissecting microscope. The resulting corneal reaction was shown to be a reliable method in the detection and estimation of delayed-type hypersensitivity in mice that had been immunized with a water-in-oil emulsion containing an ovalbumin and a cell wall adjuvant. Unlike the delayed skin reaction in the ear lobe, this corneal reaction was not affected by a coexisting Arthus reaction.

Animals↗