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Biomedical subjects

T Kojima

Publications and source records attributed to T Kojima.

At least 37 records · Page 2Linked to original sources

Elevated serum IgG titer and avidity to Actinobacillus actinomycetemcomitans serotype c in Japanese periodontitis patients.

AIM: The purpose of this study was to characterize serum antibody responses to different serotypes of Actinobacillus actinomycetemcomitans strains in various forms of periodontitis and to determine whether any specific type of A. actinomycetemcomitans was associated with any specific form of periodontitis in a Japanese population. METHODS: Sonicated whole cell and autoclaved serotype antigens of A. actinomycetemcomitans were used. Serum IgG titer and avidity to A. actinomycetemcomitans were measured by enzyme-linked immunoabsorbant assay (ELISA) and ammonium thiocyanate-dissociation ELISA, respectively, in 46 aggressive periodontitis patients (8 localized, 38 generalized), 28 chronic periodontitis patients, and 18 periodontally healthy subjects. The presence of A. actinomycetemcomitans in plaque and saliva samples was determined using polymerase chain reaction. RESULTS: Generalized aggressive and chronic periodontitis patients exhibited significantly higher IgG titers than healthy subjects to both sonicated and autoclaved antigens of serotype c strains, while IgG titer to serotype b (Y4) was significantly higher in localized aggressive periodontitis patients compared to healthy subjects. No A. actinomycetemcomitans was detected in localized aggressive periodontitis patients. A. actinomycetemcomitans-positive patients exhibited significantly higher IgG titer and avidity to serotype c than A. actinomycetemcomitans-negative patients. In A. actinomycetemcomitans-positive patients, a significantly positive correlation was observed between antibody titer and avidity to serotype c. A. actinomycetemcomitans-positive patients with generalized aggressive periodontitis showed lower IgG avidities to serotype c than those with chronic periodontitis, though no statistically significant difference was found. CONCLUSION: A. actinomycetemcomitans serotype c may play a significant role in chronic and generalized aggressive periodontitis, while A. actinomycetemcomitans serotype b may be associated with localized aggressive periodontitis in a Japanese population.

Actinobacillus Infections↗

Obesity enhances the induction of plasminogen activator inhibitor-1 by restraint stress: a possible mechanism of stress-induced renal fibrin deposition in obese mice.

BACKGROUND AND OBJECTIVES: Cardiovascular/thrombotic diseases are frequently induced by a variety of stressors. Obese patients are susceptible to thrombotic diseases associated with stress, but the underlying mechanism is still unknown. We have begun to investigate the expression of a primary inhibitor of fibrinolysis, plasminogen activator inhibitor-1 (PAI-1), in association with tissue thrombosis, using restraint-stressed obese mice. METHODS AND RESULTS: We analyzed the expression of PAI-1 after restraint (immobilization) stress in genetically obese mice in comparison with their lean counterparts. Dramatic increases in PAI-1 antigen in plasma and in tissue extracts were observed in the obese mice exposed to restraint stress. The induction of PAI-1 mRNA by stress in the tissues was also pronounced in the stressed obese mice as compared with the lean mice, especially in the hearts and adipose tissues. In situ hybridization analysis revealed that strong signals for PAI-1 mRNA were localized in the adipocytes, cardiovascular endothelial cells, and renal glomerular cells of the stressed obese mice. Histological examination revealed that renal glomerular fibrin deposition was detected only in the obese mice after 2 h of restraint stress. CONCLUSIONS: Obesity enhances the stress-mediated PAI-1 induction in the blood and tissues. This phenomenon may be associated with the increased risk of stress-induced renal fibrin deposition in obese subjects.

Adipocytes↗

Neuropeptides stimulate production of interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha in human dental pulp cells.

OBJECTIVE: Orthodontic tooth movement causes inflammatory reactions in the periodontal membrane and dental pulp. It has been reported that substance P (SP) and calcitonin gene-related peptide (CGRP), both sensory neuropeptides, are manifested in the dental pulp of rats during experimental tooth movement, suggesting that they might be involved in the dental pulp inflammation during orthodontic tooth movement. However, the relationships between neuropeptides and pro-inflammatory cytokines have not been fully elucidated. MATERIALS AND METHODS: Human dental pulp (HDP) fibroblasts were prepared from 6 healthy young volunteers (3 males, 3 females; 15-25 years old) during the course of orthodontic treatment. HDP cells were incubated for 24 h in fresh medium containing 2% FCS in the presence of various concentrations of CGRP (10(-12) to 10(-4) M) and SP (10(-12) to 10(-4) M), and the levels of interleukin (IL)-1 beta, IL-6, and tumor necrosis factor (TNF)-alpha present in the media were determined using commercially available high-sensitivity enzyme-linked immunosorbent assay kit. RESULTS: We examined the effects of stimulation by these neuropeptides on the production of inflammatory cytokines in HDP fibroblasts, and found that the levels of IL-1 beta, IL-6, and TNF-alpha increased in a time- and concentration-dependent manner. However, the neuropeptides did not act synergistically to increase cytokine secretion in HDP cells or significantly modify LPS-induced cytokine production by HDP cells. CONCLUSIONS: Our results suggest that human pulp fibroblasts may be involved in the progress of inflammation in pulp tissue during orthodontic tooth movement, as they produced large amounts of IL-1 beta, IL-6, and TNF-alpha following stimulation with neuropeptides.

Calcitonin Gene-Related Peptide↗

Prototype of simulation of orthognathic surgery using a virtual reality haptic device.

A maxillofacial simulator can support education and training. In the present study, cutting, separation, and quantitative rearrangement of bone during orthognathic surgery were simulated by means of a haptic device with virtual tactile perception. Computed tomographic (CT) images of two patients with severe jaw deformity, one women and one man, were input into the device. In the woman, Le Fort I osteotomy of the maxilla and sagittal splitting ramus osteotomy of the mandible were initially simulated. During surgery with the haptic device, separation and rearrangement of the maxilla and the ramus of the mandible were initially processed. However, there was discrepancy and overlapping of the ramus with the mandible. Intraoral vertical osteotomy of the right ramus was then performed, with satisfactory results and less discrepancy and interference. The simulation was referred to at surgery, and satisfactory surgical assistance was postoperatively confirmed on CT images. The male patient had severe jaw deformity due to unequal growth between the ramuses, resulting in anterior crossbite. Sagittal splitting ramus osteotomy with rotation of the mandible was successfully simulated. Because of its versatility and functions, the present device was found to be useful for simulating various procedures for orthognathic surgery and thereby three-dimensionally determine surgical movements.

Adult↗

Computer-assisted morphological analysis of dental casts with maxillary prognathism and reversed occlusion.

The morphologic characteristics of the dentition with maxillary prognathism and reversed occlusion were examined by a computer-assisted dental cast analysing system. Dental casts with normal occlusion, maxillary prognathism and reversed occlusion were selected and measured by a 3D shape measuring system. The dental arches and anteroposterior occlusal curves were approximated numerically by the polynomial expression with a fourth order and second order coefficients, respectively. The coefficients were analysed statistically. Maxillary dental arches with mandibular prognathism showed a more acuminate shape (V-shape) with a significant larger second order coefficient, while arches with reversed occlusion showed more angulate shapes (U-shape) with significantly smaller second order coefficients compared with arches with normal occlusions. However, a notable difference in the shape of the mandibular dental arches was not observed. The mandibular dental arches with maxillary prognathism were positioned backward relative to maxillary dental arches, while the arches with reversed occlusion were positioned forward. The anteroposterior occlusal curves with maxillary prognathism showed larger curvatures in maxilla and mandible, while the curves with reversed occlusion showed smaller curvatures in mandible comparing with the curves with normal occlusion. These results suggest that the present method could offer a useful and objective examination technique for the diagnosis of malocclusion.

Adolescent↗

Trace of native cattle in Japanese Holstein assessed by mitochondrial DNA sequence polymorphism.

On the basis of sequence variation in the displacement loop region of mtDNA, 588 Japanese and North American Holstein cows were classified into 5 mitochondrial haplotypes, which were found in Japanese Black cattle. One of the haplotypes (named type 1), which was present at the highest frequency in Japanese Black cattle, was not observed in either European or African cattle. This haplotype is characterized by 2 single-nucleotide polymorphisms. One is called the type B polymorphism, and it refers to a base change from T to C at nucleotide 16042 of the mitochondrial genome (T160042C). The other is called the type I polymorphism, and it refers to the base change as G16093A. The proportion of the Japanese Holstein population with both polymorphisms was 18.3%, whereas none of the North American cows had this genotype. Because the mitochondrial types were inherited maternally, it is clear that a considerable number of Japanese Holstein cows are descended from native Japanese cattle. Polymorphisms B and I accounted for no variance in the estimated breeding value for milk production among cows from the Hyogo herd (582 cows) or the Chiba region herd (758 cows). This result suggests that most autosomal genes of native animals have been successively replaced by those of pure Holstein after grading up of over 15 generations, even though resulting animals have native animal-oriented mitochondrial types and may still have some number of the native autosomal genes.

Animals↗

Vitamin K concentrations in the maternal milk of Japanese women.

AIM: To determine the concentration of vitamin K including K1 (phylloquinone) and K2 (menaquinone-n; MK-n) in the maternal milk of Japanese women. METHODS: We collected human milk samples from more than 4000 mothers living throughout Japan from December 1998 to September 1999, and analysed the contents of vitamin K1 and K2 in 834 of the samples. We defined as group A the 555 samples among them that met the following conditions: breast milk of mothers who were under 40 y old, not in the habit of smoking and/or using vitamin supplements, and whose babies showed no symptoms of atopy and whose birthweights were 2.5 kg or more. Vitamins extracted from the enzymatic hydrolysates of the human milk were purified with a Sep-Pak Plus silica cartridge, and then measured by a method based on high-performance liquid chromatography (HPLC) combined with coulometric reduction and fluorometric detection. RESULTS: The mean concentration of vitamin K (K1 + K2) of mothers of group A and all groups were 0.434 +/- 0.293 and 0.517 +/- 1.521 microg/100 ml (average +/- SD), respectively, and menaquinones containing 4, 6 and 7 isoprenoid residues could be detected in the milk samples. Vitamins K1 and MK-4 were found to be predominant in the milk samples, and the concentration of MK-4 in colostrum was higher than that of MK-4 in mature milk. We also found that the MK-7 concentration in the milk of mothers living in eastern Japan was higher than that of mothers living in western Japan. CONCLUSION: The different features of vitamin K1 and MK-7 concentrations in the milk of Japanese women may be due to differences in dietary foods.

Adult↗

Gene expression of leukemia inhibitory factor (LIF) and macrophage colony stimulating factor (M-CSF) in bovine endometrium during early pregnancy.

Leukemia inhibitory factor (LIF) and macrophage colony stimulating factor (M-CSF), members of the group of hemopoietic cytokines, play a primary role in the control of embryo development and implantation and in the growth of the placenta in humans and mice. Gene expressions of LIF and M-CSF were investigated using quantitative RT-PCR in bovine endometrial tissues during early and mid-pregnancy (Days 16-17, 20-21, 30-36, 48-49 and 74-140) and during the estrous cycle (Days 13-14). Leukemia inhibitory factor and M-CSF genes were expressed in all samples examined. Significant differences were found between the gene expression patterns of LIF and M-CSF. Leukemia inhibitory factor expression level at Days 48-49 was the highest in caruncular endometrium, however, the large variability negated any significant differences. Leukemia inhibitory factor expression levels in intercaruncular endometrium at Days 48-49 and 74-140 of pregnancy were greater than at Days 13-14 of the estrous cycle and at other days of pregnancy. No significant change was recognized in M-CSF expression levels in caruncular endometrium. Macrophage colony stimulating factor expression level in intercaruncular endometrium at Days 74-140 was greater than those of the other samples. These results suggest that LIF and M-CSF are produced in the endometrium and may play different roles in early and mid-pregnancy.

Animals↗

Change in apoptosis in the gastric surface epithelium and glands after eradication of Helicobacter pylori.

BACKGROUND: Change in apoptosis in gastric glands after eradication of Helicobacter pylori has never been reported. AIMS: The purpose of this paper is to investigate the change in apoptosis in gastric glands after eradication of Heliobacter pylori. PATIENTS AND METHODS: We studied 23 Heliobacter pylori-positive patients with duodenal and gastric ulcers, who were monitored for 6-12 months after eradication, and eight controls. Biopsies were taken from the antrum and body. Apoptosis was evaluated immunohistochemically using anti-single stranded DNA antibody. Apoptotic index was calculated by counting immunostained cells in surface epithelial and glandular cells. RESULTS: In the surface epithelium, Apoptotic indexes were significantly higher in patients than in controls. In the upper portion of fundic glands, apoptotic indexes were significantly higher in patients with gastric ulcers (14.2% (9.3, 17.8)) (median (1st quartile, 3rd quartile)) than in controls (8.0% (2.0, 9.0), p < 0.01) and decreased significantly after eradication (3.4% (2.0, 5.3)), p < 0.01). In pyloric glands, apoptotic indexes were no different between patients and controls. In the lower portion of fundic glands, apoptotic indexes were very low, both in patients and in controls. CONCLUSIONS: Our results showed that apoptosis, not only of surface epithelial cells but also of glandular cells in the upper portion of fundic glands, increased in Heliobacter pylori-positive patients with gastric ulcers and decreased to normal levels after eradication of Heliobacter pylori.

Adult↗

Aberrant HS1 molecule in a patient with systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the activation of autoreactive B lymphocytes, which are supposed to carry aberrant signal transduction after the stimulation of B-cell receptor (BCR). To investigate abnormalities in BCR-mediated signaling pathway in lupus B lymphocytes, we analyzed HS1, a molecule downstream of BCR, in 80 Japanese SLE patients. We identified 37 amino acid deletion of HS1 in a 25-year-old female patient, and the aberrant HS1 lacked a part of a functional motif. Analysis of genomic DNA revealed that the aberrant HS1 was caused by exon skipping. Family study showed that the patient as well as her father and sister are heterozygous for the abnormality. WEHI-231 cell, a mouse B cell line, transfected with the aberrant HS1 displayed a significantly increased cell death upon cross-linking of BCR. Additionally, peripheral B lymphocytes from the patient exerted increased apoptosis after BCR stimulation compared to those from control SLE patients. These data suggest that the aberrant HS1 molecule may transmit an accelerated signal after BCR stimulation and may play a role in the activation of autoreactive B lymphocytes.

Adaptor Proteins, Signal Transducing↗

A preliminary report on a computer-assisted dental cast analysis system used for the prosthodontic treatment.

To accomplish computerized 3D morphological analyses of maxillary and mandibular casts with malocclusions on the same co-ordinate system, a new reference co-ordinate located on soft tissue has been proposed consisting of the top of maxillary bilateral tubercles and incisive papilla on the maxillary cast. To test the validity of this co-ordinate system, the angles of the occlusal plane in this system were examined on 10 subjects with normal occlusion. In addition, to analyse maxillary and mandibular casts on the same co-ordinate system, a bite block was made under the intercuspal position. The maxillary cast was measured by 3D measuring system, then, the bite block was placed on maxillary casts, and measured similarly. To examine the position reproducibility of this method, 3D co-ordinates of the apex of the buccal cusp of the mandibular pre-molar in five bite blocks were determined. The angles formed of the occlusal plane were 1.3 +/- 1.3 degrees and 0.2 +/- 1.1 degrees on the sagittal and frontal base plane, respectively. This co-ordinate system had enough stability to replace the occlusal plane. By the measurement of bite blocks, the co-ordinates of the mandibular cusp tips were determined within the deviation of 0.2 mm.

Dental Casting Technique↗

Spontaneous haemorrhage into metastatic brain tumours after stereotactic radiosurgery using a linear accelerator.

OBJECTIVE: To determine the incidence and clinical characteristics of spontaneous haemorrhage into metastatic brain tumours after radiosurgery. METHODS: Intratumour haemorrhage rate, clinical features, and treatment were evaluated in 54 patients with 131 brain metastases of varying origin who were treated using linear accelerator radiosurgery. The marginal dose was maintained constant at 20 or 25 Gy, irrespective of tumour size. RESULTS: Haemorrhage was identified in 7.4% of the metastases (five tumours in four patients) before radiosurgery and in 18.5% (10 tumours in 10 patients) after radiosurgery. In three cases, haemorrhage into the tumour after radiosurgery was symptomatic. Half the haemorrhages occurred within one month of radiosurgery. The changes in tumour size observed at the time of haemorrhage were an increase in one tumour, no change in five, and a decrease in four. Haemorrhage into a tumour after radiosurgery was more likely to occur in female patients, in tumours with a larger volume on pretreatment neuroimaging, and in tumours treated with a larger number of isocentres or a higher maximum dose. Haemorrhagic features in the patients or their tumours on presurgical assessment were not disposing factors to haemorrhage after radiosurgery. CONCLUSIONS: When larger brain metastases are aggressively treated by radiosurgery, better local control may be attained but there may also be a higher risk of haemorrhage soon after the treatment.

Adult↗

LPS-stimulated human gingival fibroblasts inhibit the differentiation of monocytes into osteoclasts through the production of osteoprotegerin.

Periodontitis is an inflammatory bone disease caused by Gram-negative anaerobic bacteria, but the precise mechanism of bone destruction remains unknown. Activated T lymphocytes secrete receptor activator of NF-kappaB ligand (RANKL) and support the differentiation of monocytes into mature osteoclasts. The purpose of this study was to examine the expression of RANKL and its inhibitor, osteoprotegerin (OPG), in inflamed gingival tissue and to clarify the role of human gingival fibroblasts (HGFs) in osteoclastogenesis regulated by RANKL. HGFs and gingival mononuclear cells (GMCs) were obtained from chronic periodontitis patients during routine periodontal surgery. Expression of OPG and RANKL mRNA in gingival tissue and HGFs was examined with RT-PCR. OPG production was measured using ELISA. Expression of RANKL, CD4, CD8 and CD69 on GMCs was determined by flow-cytometry using RANK-Fc fusion protein and the respective monoclonal antibodies. Osteoclastogenesis by RANKL was assayed by counting the number of tartarate-resistant acid phosphatase (TRAP)-positive cells after culturing human peripheral blood monocytes with recombinant human RANKL and macrophage-colony stimulating factor (M-CSF) for 10 days. OPG and RANKL mRNA were expressed in 80% (16/20) and 25% (5/20) of periodontitis lesions, respectively. OPG, but not RANKL, mRNA was expressed within HGFs. OPG mRNA expression and production by HGFs was augmented by LPS stimulation. All GMC samples expressed CD69, and two of five GMC samples expressed RANKL. The culture supernatant of LPS-stimulated gingival fibroblasts significantly reduced the number of TRAP positive cells generated by culturing monocytes with RANKL and M-CSF. The present study suggests that LPS-stimulated HGFs inhibit monocyte differentiation into osteoclasts through the production of OPG.

Antigens, CD↗

Radial closing wedge osteotomy for Kienböck's disease: an over 10 year clinical and radiographic follow-up.

Thirteen patients with Kienböck's disease who had undergone a radial closing wedge osteotomy were reviewed clinically and radiologically at a follow-up mean of 14 years. Good long-term results were obtained in all patients. Their levels of pain were improved, and significant increases were seen in the range of motion and grip strength. Radiographic stage, as assessed by Lichtman's classification, improved in one, did not change in four, and advanced in eight patients. The radial inclination angle significantly decreased and the carpal-ulnar distance and lunate covering ratios both increased, demonstrating that radial shift in the alignment of the carpal bones occurs and that the joint contact area of the lunate increases in proportion to the decrease in radial inclination. The preoperative radiolunate and radioscaphoid angles, which were significantly larger than those of the unaffected wrist, did not change postoperatively which shows that this technique was not able to correct the flexion deformity of the lunate and the scaphoid.

Adolescent↗

Patients with systemic lupus erythematosus show a normal responsive search score in exploratory eye movement analysis: comparison with schizophrenia.

OBJECTIVE: To assess whether a difference in psychiatric vulnerability exists between patients with systemic lupus erythematosus (SLE) and those with schizophrenia. METHODS: Twenty women with SLE underwent exploratory eye movement analysis, and a responsive search score (RSS) was obtained, two months after the onset of the disease. Fifteen women with schizophrenia in remission also underwent this analysis. Exploratory eye movement was recorded by an eye mark recorder, which detects corneal reflection of infrared light. The number of eye fixations (instance of more than 0.2 seconds of eye fixation time) was recorded, and the RSS was calculated from eye fixation analysis. RESULTS: Mean (SD) RSS differed significantly between patients with SLE and those with schizophrenia (9.85 (1.87) v 7.27 (1.58) points, respectively, p<0.0001), whereas no difference in mean RSS was found between patients with SLE and 19 normal women. No difference in mean RSS was found between patients with active SLE and those with inactive SLE (9.51 (1.87) v 10.0 (1.77) points). CONCLUSION: The psychiatric vulnerability in patients with SLE, measured by the RSS, differs from that in patients with schizophrenia.

Adult↗