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Biomedical subjects

O Takagi

Publications and source records attributed to O Takagi.

At least 19 recordsLinked to original sources
PubMed1998

Differentiation of clinical isolates of Actinobacillus actinomycetemcomitans using an insertion sequence, ISAa1.

We previously identified an IS200-like sequence (ISAa1) in the genome of Actinobacillus actinomycetemcomitans FDC Y4. One or more hybridizing bands to the ISAa1 probe were detected in each of several reference strains, representing three of the serotypes (a through c) of A. actinomycetemcomitans. In this study, we examined whether a restriction fragment-length polymorphism (RFLP) with ISAa1 as a probe could differentiate clinical isolates. One or more hybridizing bands were detected in each of the 27 strains examined, which could be divided into seven groups according to restriction fragment-length polymorphism pattern. Several strains were observed with identical restriction fragment-length polymorphism types but with different serotypes. Conversely, strains were also observed with differing restriction fragment-length polymorphism types and identical serotypes.

Adolescent↗
PubMed1998

Influence of nail varnish on the remineralization of enamel single sections assessed by microradiography and confocal laser scanning microscopy.

Single-section techniques are attractive in enamel de- and remineralization investigations because they allow longitudinal studies in which mineral changes can be assessed by microradiography (TMR). Nail varnish (NV) is in general applied to coat the cut thin-section sides. The aims of this study were to investigate: (1) NV penetration depth in cut surfaces of demineralized enamel, (2) the influence of NV on cut surfaces of demineralized enamel on TMR, (3) the influence of NV penetration on a following remineralization. Cut surfaces of thin sections of demineralized enamel were NV coated; the NV was peeled off and the penetration depth assessed by confocal laser scanning microscopy. The NV penetration was 18+/-5 micrometer (mean+/-SD) in demineralized enamel. To evaluate the possible influence of NV on TMR, cut surfaces of thin sections of demineralized enamel were coated (twice) and microradiographed before and after nail varnishing. The NV effect (total effect of penetrated and surface NV) on the main parameters of TMR, Ld and DeltaZ, was less than 5% of the mean values. In the remineralization experiment (remineralization with 1.5 mM Ca2+, 0.9 mM phosphate, pH 7, 1 ppm F for 1 and 2 weeks), lesions in bulk samples, lesions in thin sections with NV-coated cut surfaces and lesions in thin sections in a PMMA (polymethylmethacrylate) holder were compared. (1) The remineralization of bulk samples and of NV-coated thin sections is different in one aspect. The amounts of mineral deposited in the lesions expressed as DeltaZ are comparable after 1 week. But because the NV penetrates part of the lesion outside, there was an Ld difference. The lesion depth difference between bulk lesions and NV-coated lesions in thin sections was statistically significant and was about 19% less in NV-coated lesions after 1 week; after 2 weeks of remineralization there was no difference in Ld between bulk- and NV-coated lesions any more. (2) There was no difference in remineralization efficacy between lesions in bulk samples and lesions in thin sections in the PMMA holder.

Adolescent↗
PubMed1997

Cloning and sequencing of part of the S10 operon from Actinobacillus actinomycetemcomitans FDC Y4.

We have cloned and sequenced the 5.2 kb EcoRI fragment that contained part of the S10 operon from Actinobacillus actinomycetemcomitans FDC Y4. The order of the ribosomal protein genes was identical to that of the S10 operon of Haemophilus influenzae and Escherichia coli. The deduced amino acid sequences of ribosomal proteins in this operon displayed significant homologies (65.3%-100%) to those of H. influenzae, E. coli, Yersinia enterocolitica and Yersinia pseudotuberculosis. Phylogenetic trees obtained for these ribosomal proteins were similar to that obtained for 16S rRNA.

Aggregatibacter actinomycetemcomitans↗
PubMed1997

A computer-assisted videodensitometric method to visualize mineral distributions in in vitro and in vivo formed root caries lesions.

A computer-assisted videodensitometry (CAV) method is presented for the microradiographical mineral determination and mineral visualization of in vitro and in vivo formed dentin lesions. The method employs as essential steps (1) image digitizing by a CCD camera, (2) conversion of gray values to equivalent aluminium thicknesses and (3) conversion of aluminium thickness to vol% of mineral. Procedure and accuracy are described. The CAV method is illustrated for dentin lesions formed in vitro as well as for clinical root caries lesions. The CAV method is especially advantageous for clinical lesions because it can be employed for very complex mineral distributions and irregular lesion outlines. In given areas of interest, the mineral distribution (in vol%) can be plotted in 3D form in pseudo-colors. Conventional microradiographical profiles can be obtained directly from the CAV images. For in vitro lesions, the mineral distribution parameters, lesion depth, mineral loss, and mineral acquisition values can be generated from CAV images with a reproducibility of better than 7%. The CAV method is a valuable tool in quantitative mineral studies of clinical lesions in extracted teeth as well as in in situ lesion investigations.

Absorptiometry, Photon↗
PubMed1996

Molecular analysis of a new insertion sequence from Actinobacillus (Haemophilus) actinomycetemcomitans FDC Y4.

We have found a new insertion sequence (IS), designated ISAa1, downstream of the S10 operon in Actinobacillus (Haemophilus) actinomycetemcomitans FDC Y4. ISAa1, the first IS element characterized in this organism, is 705 bp long and lacks terminal inverted repeats. This element displayed significant homology with IS200. Hybridization patterns of genomic DNA of seven A. actinomycetemcomitans strains with an internal ISAa1 probe varied depending on the serotypes, suggesting that ISAa1 might be a useful tool for epidemiological studies.

Aggregatibacter actinomycetemcomitans↗
PubMed1996

Effect of sodium hypochlorite treatment on remineralization of human root dentine in vitro.

Dentine consists simplified of mineral and of several organic components. Sodium hypochlorite (NaOCl) is a well-known nonspecific proteolytic agent capable to remove organic material. The aim of this study was to investigate the influence of organic material removal from artificial dentine lesions by means of NaOCl pretreatment on subsequent remineralization with and without fluoride. Human root dentine samples were demineralized in an acidic gel (pH = 5) at 37 degrees C for 2 weeks. After 2 min of pretreatment with a 0.4, 2 or 10% NaOCl solution, the samples were remineralized in a 20 mM HEPES buffer (pH = 7) containing 1.5 mM Ca(2) and 0.9 mM phosphate with or without addition of 10 ppm F(-) as NaF at 37 degrees C for 8 days. Mineral profiles were assessed by means of transversal microradiography after diol treatment to avoid shrinkage caused by drying. In a separate experiments the dentine contraction caused by 10% NaOCl was assessed. The contraction (negligible for sound dentine) was found to be about 12% for the lesions. The remineralization results showed that pretreatment with a 10% NaOCl solution for 2 min, increased lesion remineralization. After NaOCl treatment, the amount of accumulated mineral increased by about 27% without F in the remineralization solution, and by about 4% with 10 ppm in solution. The in vitro results suggest that removal of organic materials from dentine lesions is an interesting approach to enhance remineralization.

Adolescent↗
PubMed1995

The effects of a sodium hypochlorite treatment on demineralized root dentin.

The effects of a 10% NaOCl treatment for 2 min on demineralized human root dentin were investigated by means of: microradiography (MR), scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and secondary ion mass spectroscopy (SIMS). MR measurements revealed that NaOCl caused a tissue contraction not related to water loss but to removal of organic substance(s), resulting in reductions of the lesion depth and mineral loss values by 15% and 42%, respectively. CLSM observations on wet dentin showed that the dentinal tubules underneath the surface are clearly observable and not deformed substantially by the NaOCl, except near the outermost surface. This indicates the importance of wet as well as of dried (high vacuum) observations. SEM micrographs (high vacuum) showed definite changes in the outer dentin surface structure; 85% of the originally open dentinal tubules were closed after NaOCl treatment. No marked changes were observed in the dentin ultrastructure inside lesions, as shown by SEM on fractured surfaces. SIMS data, pertaining to samples in high vacuum, showed a remarkable increase of chlorine (Cl) content in the entire lesion due to the NaOCl, indicating deep penetration of the original OC1 ions. The results suggest that the 2-min treatment of demineralized dentin by NaOCl solutions removes and/or changes part of the dentin matrix in nearly the whole lesion. As a consequence the mineral is somewhat redistributed, the outermost surface of a few mu m is changed, but the main dentin structure and element composition are still intact. These findings indicate that NaOCl treatments are of interest in remineralization and hyper-remineralization studies of dentin.

Adolescent↗
PubMed1995

The influence of air-drying on hyper-remineralization of demineralized dentine: a study on bulk as well as on thin wet section of bovine dentine.

The influence of air-drying on the remineralization of demineralized bovine dentine was examined in wet bulk samples, in dried bulk samples as well as in wet thin sections. Bulk samples of bovine dentine were first demineralized in an acidic gel (pH = 5) at 37 degrees C for 3 weeks. After 24-hour pre-treatment of either air-drying or immersion in water, the bulk samples were remineralized in a solution containing 1.5 mM Ca, 0.9 mM phosphate and 10 ppm F (pH = 7) at 37 degrees C for 2, 4 or 8 days. Separately thin sections prepared from demineralized bulk dentine were immersed in water for 24 h and were also exposed to the remineralization solution for 2, 4 or 8 days. The results show that air-drying of the bulk samples increased remineralization of dentine considerably; the microradiographic parameters (ld, delta Z and la) show that the degree of remineralization ranks: thin wet sections > bulk dried > bulk wet. Especially, the remineralization inside lesions was greatly enhanced in thin sections and dried samples. It is presumed that the increased remineralization in dried samples is caused by a 'sponge effect', in which the remineralization fluid is sucked up in a dried shrunken lesion, resulting in fast and deep penetration of remineralization solution and/or presumably increased nucleation.

Air↗
PubMed1992

Caries experience in subjects 18-22 years of age after 13 years' discontinued water fluoridation in Okinawa.

The purpose of this study is to compare the state of teeth in young adults who had consumed fluoridated water from birth to 5-8 yr of age with the subjects who had non-fluoridated water. The sample consisted of 117 18-22-yr-old female nursing school students. The data obtained in dental examinations were sorted according to their place of residence, and then divided into groups depending on whether their place of residence had been supplied with fluoridated water or not. The fluoride concentration in the water had been 0.7-1.0 ppm in the six water supply systems which were under the control of the US military base. In the subjects who had fluoridated water, the following differences were found when compared to the control subjects: missing teeth and highly progressed caries occurred less frequently; significantly lower caries prevalence was present on free smooth and approximal surfaces; the overall DMFT differences in favor of the fluoridated subjects were small and non-significant.

Adolescent↗
PubMed1992

[A case of interstitial pneumonitis associated with polymyositis complicated by renal cell carcinoma].

A 55-year-old woman was referred to the department of urology in our hospital with left renal tumor, discovered during examinations at another hospital for fever and dyspnea on exertion. Because surgery was difficult due to severe hypoxemia, pulmonary function impairment (restrictive) and bilateral diffuse interstitial shadows on chest X-ray film, the patient was referred to our department. Interstitial pneumonitis was found on transbronchial lung biopsy, and serum GOT, LDH and CPK values were elevated. These symptoms and abnormalities of laboratory data were improved by administration of prednisolone 60 mg/day, and left nephrectomy was performed without any complications. Pathological examination of the surgical specimen showed clear cell carcinoma (Grawitz). Steroid therapy was tapered off and her clinical course was good. Six months after surgery, the patient developed a recurrence of fever, which was not responsive to antibiotics. Polymyositis was diagnosed on the basis of elevated serum GOT, LDH and CPK, electromyogram and muscle biopsy findings and positive anti-Jo-1 antibody. Polymyositis/dermatomyositis is sometimes associated with interstitial pneumonitis or malignant neoplasms, but rarely with both simultaneously. Moreover, renal cell carcinoma is very rare among the malignant neoplasms associated with polymyositis/dermatomyositis, and we therefore report this unusual case.

Antibodies, Antinuclear↗
PubMed1991

[A case of exogenous lipoid pneumonia showing a coin lesion with cavities].

A 26-year-old male was referred to our department because of an abnormal chest X-ray, obtained during a routine physical examination in the hospital admitted after a traffic accident. The P-A chest film revealed a coin lesion with cavities in the left S9. He complained of no symptoms except for expectoration of bloody sputum. Transbronchial lung biopsy specimens showed destruction of normal alveolar pattern and collections of lipid-laden macrophages enclosed by fibrous tissue. The lipid material of macrophages in sputum was stained with Sudan III. He had no difficulty in swallowing and no history of regular use of oily drugs. Fiberoptic bronchoscopy and chest CT showed no obstruction of bronchi. He had been working in a repair shop for motorcycles for years, therefore the lesion could be an occupational exogenous lipoid pneumonia. The diameter of the coin lesion has decreased without any therapy.

Adult↗
PubMed1990

[Three cases of pneumothorax due to lung cancer].

Spontaneous pneumothorax due to primary lung cancers are increasingly reported as of lung cancer incidence increased. We experienced one lung cancer case with pneumothorax as a primary symptom and two who developed pneumothorax after chemotherapy, among 238 cases of primary lung cancer. In the literature, 76 cases of pneumothorax due to primary lung cancers are described. The mechanism of pneumothorax is discussed.

Adult↗
PubMed1987

[Cognitive changes in decision making process underlying prosocial behavior].

Using a method of monitoring information acquisition, 76 subjects were instructed to simulate the information search process in which they selected a behavior from available behavioral alternatives which were expected to occur in a situation where donating behavior was needed. In order to measure the cognitive changes, they were asked to rate the importance of behavioral attributes both before and after the decision task. After the decision task, they were asked to rate the inner states. (1) Defensive cognitive changes were found which increased the importance of behavioral costs and decreased the importance of personal moral obligation feelings. This pattern of changes was consistent with the Schwartz & Howard model (1981, 1982, 1984). (2) The defensive cognitive changes were related to the information search strategies. This pattern of relationship partly confirmed the prediction derived from the Schwartz & Howard model (1981, 1982, 1984). (3) The result that the cognitive changes were not related to the inner states was inconsistent with the model of either Piliavin, Dovidio, Gaertner, & Clark (1981, 1982) or Schwartz & Howard (1981, 1982, 1984). An alternative model was proposed and discussed.

Adult↗
PubMed1986

Plasminogen activator in bronchoalveolar fluid.

Plasminogen activator was purified from the soluble fraction of bronchoalveolar lavage fluid, and biological and immunological characteristics of the activator were examined by electrophoretic enzymography. The purified fraction showed a single band with a molecular weight of 53,000. The enzyme activity was eliminated in the presence of DFP and did not display fibrin affinity. Immunological tests revealed that the plasminogen activator reacted with IgG of antiurokinase but not with that of tissue-type plasminogen activator. However, the plasminogen activator cleaved S-2288 to a greater extent than S-2444 in contrast to urokinase.

Adult↗
PubMed1983

Influence of tooth-to-denture-base discrepancy on space closure following premature loss of deciduous teeth.

Influence of tooth-to-denture-base discrepancy on so-called physiologic migration of the first molar was studied on serial dental casts of 116 boys and girls, obtained through a dental health program for school children in an area in which there was no dentist. The alteration of spaces following premature loss of deciduous molars was examined comparing the anterior to posterior discrepancies between tooth and denture base. Modes of space alteration showed positive correlation with the size of the discrepancy, especially in the mandibular dental arches. The space deficiency in the posterior region seemed to have a positive effect on the mesial migration of the first molar. Mesial migration of the first molar seems to be pathologic rather than physiologic and is strongly affected by tooth-to-denture-base discrepancies. Space maintenance does not seem to be useful, because it is not necessary in minimum discrepancy cases and is not effective in severe discrepancy cases.

Adolescent↗