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Chiba M, Sera K, Hashizume M, Shimoda T, Sasaki S, Kunii O, Inaba Y. Element concentrations in hair of children living in environmentally degraded districts of the East Aral Sea region. J Radioanal Nucl Chem 2004. [DOI: 10.1023/b:jrnc.0000015820.61512.b9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Kaneko K, Chiba M, Hashizume M, Kunii O, Sasaki S, Shimoda T, Yamashiro Y, Caypil W, Dauletbaev D. Renal tubular dysfunction in children living in the Aral Sea Region. Arch Dis Child 2003; 88:966-8. [PMID: 14612357 PMCID: PMC1719339 DOI: 10.1136/adc.88.11.966] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND The Aral Sea region is a natural area seriously polluted by human activities. Recent surveillance revealed the increased prevalence of diverse chronic diseases in children. AIMS To investigate the function of renal tubules, which are most at risk of damage as a result of heavy metal intoxication, in children of the Aral Sea region. METHODS A group of 205 children living in Kazalinsk, close to the Aral Sea, and a group of 187 children living in Zhanakorgan, far from the Aral Sea, were examined by means of random urine samples. Both urinary N-acetyl-beta-D-glucosaminidase (NAG; U/mmol Cr) and beta2 microglobulin (BMG; microg/mmol Cr) were calculated for each subject. RESULTS Mean urinary NAG and BMG were both significantly higher in Kazalinsk than in Zhanakorgan (NAG: 0.77 (0.58) and 0.62 (0.37) U/mmol Cr; BMG: 41.8 (54.8) and 22.5 (20.4) microg/mmol Cr, respectively; mean (SD), p < 0.01). The number of children with abnormal values of NAG (>1.5 U/mmol Cr) was significantly more prevalent in Kazalinsk than in Zhanakorgan (7.9% and 2.6%, respectively, p < 0.05). CONCLUSION Renal tubular function of children around the Aral Sea region is profoundly impaired. This should be taken into account when considering the health problems of this area.
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Komatsu K, Kanazashi M, Arai T, Chiba M. Effects of hydrocortisone and beta-aminopropionitrile on stress-strain and stress-relaxation behaviors, and birefringent retardation of collagen fibers in the rat incisor periodontal ligament. Connect Tissue Res 2003; 43:581-8. [PMID: 12685864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Three groups of male Wistar rats received daily subcutaneous injections of 10 mg/kg of hydrocortisone (HC group), 300 mg/kg of beta-aminopropionitrile (BAPN group), or saline (control group), for 10 days. The shear stress-strain and stress-relaxation properties of the incisor periodontal ligament were examined in transverse sections from dissected mandibles. Both the maximum shear stress and failure strain energy density increased significantly following the administration of hydrocortisone. The maximum shear stress decreased following the administration of BAPN. However, the stress-relaxations in the initial 10 min did not show significant differences among the three groups. Polarized light microscopic analysis revealed that the retardation value of the collagen fibers was highest in the HC group and lowest in the BAPN group for the bone-related area, but not for the tooth-related and middle areas of the ligament. It is suggested that the changes induced by hydrocortisone or BAPN occurred mainly in the elastic components and to a minor extent in the viscous components although the physical and biomechanical properties are determined by the interaction of all the various components. We also suggest that the main response to the drugs occurred in the collagen fibers in the bone-related area of the ligament.
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Jin L, Chen IW, Chiba M, Lin JH. Interaction with indinavir to enhance systemic exposure of an investigational HIV protease inhibitor in rats, dogs and monkeys. Xenobiotica 2003; 33:643-54. [PMID: 12851040 DOI: 10.1080/0049825031000089128] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
1. The use of a beneficial interaction between indinavir and compound A, a potent investigational HIV protease inhibitor to enhance systemic exposure of compound A, was investigated. 2. When administrated alone, compound A underwent extensive hepatic first-pass metabolism in rats and monkeys, resulting in low oral bioavailability. 3. In vitro studies with liver microsomes revealed that compound A metabolism was mediated exclusively by CYP3A enzymes in rats, dogs and monkeys. Indinavir, which also was metabolized predominantly by CYP3A enzymes, extensively inhibited compound A metabolism in microsomes, whereas compound A showed weak inhibitory potency on indinavir metabolism. 4. Consistent with in vitro observations, co-administration of the two compounds resulted in a 17-fold increase in oral AUC of compound A in rats owing to the inhibition of metabolism of compound A by indinavir, whereas compound A did not affect indinavir metabolism as indicated by the unchanged indinavir AUC. Similarly, the systemic exposure of compound A in dogs and monkeys was increased substantially following oral co-administration with indinavir by 7- and > 50-fold, respectively. 5. Enhancement in compound A systemic exposure by indinavir in humans, as predicted based on the in vivo animal and in vitro human liver microsomal data, was confirmed in subsequent clinical studies.
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Hashizume M, Kunii O, Sasaki S, Shimoda T, Wakai S, Mazhitova Z, Dauletbaev D, Caypil W, Aldiyarova M, Farmer A, Yamashiro Y, Chiba M. Anemia and iron deficiency among schoolchildren in the Aral Sea region, Kazakhstan. J Trop Pediatr 2003; 49:172-7. [PMID: 12848209 DOI: 10.1093/tropej/49.3.172] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The objectives of this study were to estimate the prevalence of anemia and iron deficiency among schoolchildren in the Aral Sea region of Kazakhstan and to determine the various factors associated with anemia in this population. We conducted a cross-sectional study of randomly selected schoolchildren. Blood samples were collected for measuring hemoglobin (Hb), serum ferritin (SF), total iron binding capacity (TIBC), and other hematological indices, and subjects were screened for anemia and iron deficiency. Associations between Hb concentration and SF, TIBC, anthropometric, and socioeconomic data were evaluated using regression analysis. The prevalence of anemia was 49.8 per cent although levels were mostly mild. Twenty-two per cent of the children were iron depleted (SF < 12 microg/l). Of the anemic children, 32.4 per cent were found to have iron deficiency anemia (anemia with SF < 12 microg/l). There were significant positive correlations between the levels of Hb and SF, but a negative correlation with serum TIBC. Age, mean corpuscular volume (MCV) and SF were found to be significantly related to Hb by stepwise multiple regression analysis. Multiple logistic regression analysis revealed that anemia was independently related to living district, education of father, and child's age. The results suggest that iron deficiency is an important determinant of anemia in this population; however, whole anemia cannot be solely explained by iron deficiency. Further studies are needed for consideration of micronutrients status, parasite infestation, hereditary disorders, and exposure to environmental pollutants.
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Shimada A, Shibata T, Komatsu K, Chiba M. The effects of intrusive loading on axial movements of impeded and unimpeded rat incisors: estimation of eruptive force. Arch Oral Biol 2003; 48:345-51. [PMID: 12711378 DOI: 10.1016/s0003-9969(03)00010-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Axial movements of impeded and unimpeded rat mandibular incisors were measured following application and removal of intrusive loads of 1, 2, 5, 10 and 20 mN in a stepwise order at intervals of 1h on erupting teeth. The tooth movements were recorded by a displacement detector under artificial respiration with halothane anaesthesia. The loading and unloading procedures brought about the tooth movements in two steps: an initial rapid movement immediately after application or removal of the load and a subsequent slow and gradual movement. The initial rapid intrusive or extrusive tooth movements were significantly greater in the unimpeded than in the impeded teeth at the same load. The forces to stop extrusive tooth movements, estimated from the formula of regression lines showing correlations between the intrusive loads from 0 to 5 mN and tooth movements (microm/30 min), were 4.2 mN in the impeded and 2.9 mN in the unimpeded incisors. We suggest that repeated shortenings of the rat incisor did not cause an increase in the eruptive force and that changes in the resistance of the periodontal ligament predominantly regulate the axial movement of the rat incisor.
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Kaneko K, Chiba M, Hashizume M, Kunii O, Sasaki S, Shimoda T, Yamashiro Y, Dauletbaev D, Caypil W, Mazhitova Z. Extremely high prevalence of hypercalciuria in children living in the Aral Sea region. Acta Paediatr 2003; 91:1116-20. [PMID: 12434899 DOI: 10.1080/080352502760311638] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 09/30/2022]
Abstract
UNLABELLED The Aral Sea region is a natural area seriously polluted by human activities. In addition to the increased prevalence of diverse chronic diseases in children, the risk of developing urolithiasis is reported to be high in this region. This study was undertaken to clarify the prevalence of hypercalciuria in children of the Aral Sea region. A group of 205 children living in Kazalinsk, close to the Aral Sea, and a group of 187 children living in Zhanakorgan, far from the Aral Sea, were screened for hypercalciuria. Urinary sodium excretion (sodium per creatinine, uNa/Cr) in addition to calcium excretion (calcium per creatinine, uCa/Cr) was also calculated for each subject. Mean uCa/Cr (mmol/mmol) and uNa/Cr (mmol/mmol) excretions were significantly higher in Kazalinsk than in Zhanakorgan (uCa/Cr: 0.75 +/- 0.74 and 0.33 +/- 0.30; uNa/Cr: 3.54 +/- 2.27 and 2.89 +/- 1.69, respectively, mean +/- SD, p < 0.01). Hypercalciuria regarded as an uCa/Cr of more than 0.703 was observed in 79 out of 205 Kazalinsk children (38.6%) while this was seen in only 24 out of 187 Zhanakorgan children (12.8%). Linear regression analysis revealed a direct positive correlation between urinary calcium and sodium excretion (p < 0.01) in Kazalinsk children. CONCLUSION The prevalence of hypercalciuria in children around the Aral Sea region is extremely high. This may be associated with excessive intake of calcium and sodium, or due to impaired renal tubular function caused by toxic chemicals. Therefore, hypercalciuria that may lead to urolithiasis should be taken into account when considering the health problems of this area.
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Konishi H, Shimizu S, Chiba M, Minouchi T, Koida M, Yamaji A. Predictive performance of serum digoxin concentration in patients with congestive heart failure by a hyperbolic model based on creatinine clearance. J Clin Pharm Ther 2002; 27:257-65. [PMID: 12174027 DOI: 10.1046/j.1365-2710.2002.00418.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVES To formulate a simple equation for determining the daily dose requirements of digoxin by inclusion of creatinine clearance (Ccr) values as an explanatory variable. METHODS We included 235 routine monitoring and clinical laboratory test data (steady-state serum digoxin concentration and Ccr values), obtained from hospitalized patients receiving digoxin for treatment of congestive heart failure. The 107 data sets were fitted to a hyperbolic model to account for the relation between the ratio of serum digoxin level to the daily dose (L/D) and the Ccr values determined by six methods. Their correlation coefficients (r) were computed by non-linear regression analysis. To evaluate the validity of the best-fitting model, the predictive performance of the L/D ratios was compared with those given by seven reference models previously published, using another 128 data sets. RESULTS The hyperbolic model involving the Ccr values estimated by Cockcroft and Gault's equation showed the closest correlation (r = 0.81) between the actual and estimated Ccr values. Mean prediction error (ME), a measure of bias, of the L/D ratio (0.018 ng/mL) was almost negligible when other data were fitted to the proposed model, and this ME value proved to be much smaller than those calculated from the previously published prediction models. Mean absolute prediction error, a measure of precision, by the proposed model was also satisfactory for prediction. CONCLUSION The newly developed model provided good predictive performance of serum digoxin level. Taking simplicity in practical use into account, the clinical application of the proposed model will allow for accurate and rapid determination of the initial maintenance dosing regimen of digoxin based on the individual Ccr value, without actual measurement of its serum concentration.
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Suzuki T, Ogawa Y, Chiba M, Fukuda M, Iwasa N, Izumikawa T, Kanungo R, Kawamura Y, Ozawa A, Suda T, Tanihata I, Watanabe S, Yamaguchi T, Yamaguchi Y. Momentum distribution of 15B fragments from the breakup of 17B. PHYSICAL REVIEW LETTERS 2002; 89:012501. [PMID: 12097037 DOI: 10.1103/physrevlett.89.012501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2001] [Indexed: 05/23/2023]
Abstract
The two-neutron removal cross section (sigma(-2n)) and the longitudinal momentum distribution of 15B fragments from the breakup of 17B on 9Be were measured at 70A MeV. The distribution in the projectile rest frame is characterized by a FWHM of 80+/-10 MeV/c for 15B. The sigma(-2n) is found to be 0.22+/-0.05 b. A Glauber-type analysis of the data provides clear evidence of a two-neutron halo structure in 17B.
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Yamaguchi N, Chiba M, Mitani H. The induction of c-fos mRNA expression by mechanical stress in human periodontal ligament cells. Arch Oral Biol 2002; 47:465-71. [PMID: 12102763 DOI: 10.1016/s0003-9969(02)00022-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The periodontal ligament is subjected to mechanical loading during occlusion and mastication. Although internuclear transcription factors are associated with the regulatory pathway that converts these extracellular mechanical stimuli into a cellular response, there are no reports on these in human periodontal ligament fibroblasts. In this study, the amounts of c-fos mRNA in human periodontal ligament fibroblasts were investigated shortly after subjecting them to a cyclic tension force in vitro. The mRNA of alkaline phosphatase and the matrix proteins type I collagen, type III collagen, matrix Gla-protein, osteonectin, osteopontin, and osteocalcin were also examined. A significant, rapid, transient increase in c-fos mRNA was detected, which peaked 30 min after the application of mechanical force. However, there was no significant change in the mRNA for alkaline phosphatase or the matrix proteins. These results provide evidence that periodontal ligament fibroblasts and c-fos may play a critical part in the response of periodontal tissue to mechanical stimulation.
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Kanzaki H, Chiba M, Shimizu Y, Mitani H. Periodontal ligament cells under mechanical stress induce osteoclastogenesis by receptor activator of nuclear factor kappaB ligand up-regulation via prostaglandin E2 synthesis. J Bone Miner Res 2002; 17:210-20. [PMID: 11811551 DOI: 10.1359/jbmr.2002.17.2.210] [Citation(s) in RCA: 376] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Previously, we discovered that periodontal ligament (PDL) cells not only support osteoclastogenesis through cell-to-cell contact, but also inhibit the formation of tartrate-resistant acid phosphatase-positive (TRAP+) multinucleated cells by a producing soluble factor(s). Furthermore, PDL cells express both receptor activator of nuclear factor kappaB ligand (RANKL) and osteoprotegerin (OPG) messenger RNA (mRNA). Clinically, "ankylosed teeth," which lack periodontal ligament, cannot be moved with orthodontic tooth treatment. From this, we hypothesized that PDL cells under mechanical stress should play a pivotal role in osteoclast formation during orthodontic tooth movement. This study examined how mechanical stress affects the osteoclastogenesis-supporting activity of PDL cells. PDL cells were compressed continuously and then cocultured with peripheral blood mononuclear cells (PBMCs) for 4 weeks. PDL cells under mechanical stress up-regulated osteoclastogenesis from PBMCs. Furthermore, the expression of RANKL mRNA and protein in PDL cells increased with compressive force in parallel with the change in the number of osteoclasts. In addition, cyclo-oxygenase 2 (COX-2) mRNA expression was induced by compressive force, and indomethacin inhibited the RANKL up-regulation resulting from compressive force. PDL cells under compressive force exhibited significantly increased prostaglandin E2 (PGE2) production in comparison with control PDL cells. Exogenous PGE2 treatment increased RANKL mRNA expression in PDL cells. Interestingly, OPG expression remained constant throughout compressive force or PGE2 treatment. In conclusion, compressive force up-regulated RANKL expression in PDL cells. Furthermore, RANKL up-regulation in mechanically stressed PDL cells was dependent on PGE2.
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Okuyama K, Abe E, Suzuki T, Tamura Y, Chiba M, Sato K. Influence of bone mineral density on pedicle screw fixation: a study of pedicle screw fixation augmenting posterior lumbar interbody fusion in elderly patients. Spine J 2001; 1:402-7. [PMID: 14588296 DOI: 10.1016/s1529-9430(01)00078-x] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Some biomechanical studies have demonstrated that bone mineral density of the lumbar spine (BMD) affects the stability of pedicle screws in vitro. PURPOSE To investigate influence of BMD on loosening and related failure of pedicle screws in vivo. STUDY DESIGN/SETTING A clinical study of 52 patients who underwent pedicle screw fixation augmenting posterior lumbar interbody fusion (PLIF). PATIENT SAMPLE There were 13 men and 39 women, with an average age of 63 years (range, 45-76 years) at the time of operation. The mean follow-up period was 2.8 years (range, 2-6 years). OUTCOME MEASURES Relationship between BMD, screw loosening, and its related failures were statistically analyzed. METHODS BMD was measured by the dual energy X-ray absorptiometry (DEXA) method. Radiographic assessments were done by the first author and independently by another orthopedist who was not informed of the values of BMD. RESULTS The mean BMD of all patients was 0.879 +/- 0.215 (mean +/- S.D.) g/cm2. The mean BMD in patients with and without screw loosening was 0.720 +/- 0.078 g/cm2 (n=11) and 0.922 +/- 0.221 g/cm2 (n=41). There was a significant difference between the mean BMD of patients with and without screw loosening (P<.01). The mean BMD of patients with "union," "nonunion" and "undetermined union" was 0.934 +/- 0.210 g/cm2 (n=40), 0.674 +/- 0.104 g/cm2 (n=4) and 0.710 +/- 0.116 g/cm2 (n=8), respectively. The mean BMD of patients with "union" was significantly greater than those with "nonunion" and "undetermined union" (P<.05). CONCLUSION It could be concluded that BMD has a close relation with the stability of pedicle screws in vivo, and BMD value below 0.674 +/- 0.104 g/cm2 suggests a potential increased risk of "nonunion" when pedicle screw fixation is performed in conjunction with PLIF.
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Nishino K, Sasaki T, Takahashi K, Chiba M, Ito T. The norepinephrine precursor L-threo-3,4-dihydroxyphenylserine facilitates motor recovery in chronic stroke patients. J Clin Neurosci 2001; 8:547-50. [PMID: 11683602 DOI: 10.1054/jocn.2000.0858] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
L-threo-3, 4-dihydroxyphenylserine (L-DOPS) is a precursor of norepinephrine. We reported that administration of L-DOPS to rats with ablation of the right sensorimotor cortex results in functional recovery from deficits in beam-walking performance. We al so reported that improvement in Fugl-Meyer Score (FMS) was significantly higher in an L-DOPS-treated group of chronic neurologically stable stroke patients than in a control group for 2 days. In the present study, 27 patients who had suffered from stroke more than one month previously and had exhibited no improvement in neurological deficits for at least one week were administered 300mg/day L-DOPS for 28 days with rehabilitation. FMS improved by 4.4 points (P< 0.001), 10m gait time was shortened by 16% (P< 0.001) and the cerebral blood flow of the lesion was increased (P< 0.03), after 28 days of drug administration. These findings suggest that L-DOPS is effective in restoring neurological deficit, which does not usually recover when only treated with rehabilitation therapy.
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Hoshi A, Watanabe H, Kobayashi M, Chiba M, Inaba Y, Kimura N, Ito T. Concentrations of trace elements in sweat during sauna bathing. TOHOKU J EXP MED 2001; 195:163-9. [PMID: 11874249 DOI: 10.1620/tjem.195.163] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Trace elements in sweat during sauna bathing were assessed. Sweat collected by the whole body method was compared with that collected by the arm bag method. The sweat samples were collected from ten healthy male adults aged 22-26 years, by heat exposure in dry sauna bathing (60 degrees C, 30 minutes). Concentrations of major (Na, Cl, K, Ca, P and Mg) and trace (Zn, Cu, Fe, Ni, Cr and Mn) elements in sweat tended to be lower in the arm bag method than in the whole body method. It was found that Ca, Mg, Fe and Mn concentrations in the arm bag method were significantly lower than those in the whole body method. The amount of trace elements in sweat measured by the arm bag method was less than that by the whole body method; significant differences were observed in Fe and Mn amounts. These observations suggest that excretion of trace elements by sweating induces trace element decrease. Therefore, athletes and workers who work in a hot environment and sweat much habitually should ingest adequate amounts of trace elements.
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Komatsu K, Chiba M. Synchronous recording of load-deformation behaviour and polarized light-microscopic images of the rabbit incisor periodontal ligament during tensile loading. Arch Oral Biol 2001; 46:929-37. [PMID: 11451407 DOI: 10.1016/s0003-9969(01)00054-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Tooth-periodontal ligament-bone segments were cut in the form of rectangular prisms (1.5 mm wide, 0.65 mm thick, and long enough to allow anchorage of the bone and tooth-end portions in a stretching jig) from the mandibular incisors of 10 rabbits. The experimental set-up enabled simultaneous recording, on video, of the changing image brightness under polarizing optics together with extension across the periodontal ligament. Specimens were stretched until failure at a velocity of 0.5 mm/min. The tensile load-deformation curve of the ligament exhibited an initial, non-linear region that was followed by a linear region, a subsequent yielding region preceding the maximum point, and a final descending region. Gradual increases in the intensity of birefringence in the linear and yielding regions indicated that stress concentrations occur in the supporting fibres attached to mineralized tissues. In the final descending region of the curve, progressive breakages of individual fibre bundles occurred, mainly in the middle zone of the ligament. Analysis of the polarized light-microscopic images showed that the increases in brightness and area of birefringent collagen fibre bundles occurred in parallel with the stress generated. These results suggest that the collagen fibre bundles became aligned with the direction of loading and the intensity of their birefringence increased according to the applied tensile force.
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Yamazaki Y, Komatsu K, Arai T, Chiba M. The effects of a high-carbohydrate diet on the stress-strain behavior of the periodontal ligament of the distal root of the mandibular first molar in hamsters. J Periodontal Res 2001; 36:301-8. [PMID: 11585117 DOI: 10.1034/j.1600-0765.2001.360505.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We analyzed stress-strain curves in transverse sections at three different root levels of the cervical, middle, and apical regions of the distal root of the mandibular first molar in hamsters fed a high-carbohydrate (experimental group) or standard (control group) diet for 8 weeks. Each section was loaded in vitro at a rate of 5 mm/min in an extrusive direction. The rupture sites and the structures of birefringent collagen fibers in the periodontal ligament were also analyzed. The maximum shear stress, tangent modulus, and failure strain energy density of the periodontal ligament were significantly greater in the cervical region than in the middle and apical regions in both the control and experimental groups. The maximum shear stress, tangent modulus, and failure strain energy density of the periodontal ligament in the experimental group were significantly lower than those in the control group at the cervical and middle regions. The maximum shear strain was significantly greater in the experimental group than in the control group at the middle and apical regions. Histological sections showed that the periodontal ligament ruptured irregularly in both groups. The collagenous fibers of the ligament in the experimental group appeared to be thinner and less birefringent at the cervical and middle regions of the root. These results suggest that a high-carbohydrate diet differentially affects the collagen fibers in the periodontal ligament as a function of the root level, and that these effects are evident in changes in the mechanical properties of the ligament.
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Mochida J, Toh E, Chiba M, Nishimura K. Treatment of osteoporotic late collapse of a vertebral body of thoracic and lumbar spine. JOURNAL OF SPINAL DISORDERS 2001; 14:393-8. [PMID: 11586138 DOI: 10.1097/00002517-200110000-00004] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Although osteoporotic late collapse of a vertebral body is a common infirmity of old age, it has not been well studied, and no consensus regarding treatment of this condition has been reached. Forty-five patients with osteoporotic late collapse of a vertebral body were classified into six types based on the appearance on the lateral projection of a radiograph and the presence or absence of neurologic symptoms and were evaluated on imaging and clinical outcome. We concluded that the treatment of osteoporotic late collapse of a vertebral body can be individualized based on several factors such as the presentation of the fracture and neurologic condition. Conservative treatment can be selected in patients without neurologic involvement who have the concave type with anterior spur or sclerotic change or flat type with uniform compression of collapse. If the patients in those types of collapse show neurologic involvement, decompression and reconstruction through a posterior approach, including an eggshell procedure and the short segment pedicle screw system, are more suitable. Anterior decompression with anterior strut bone graft and anterior spinal instrumentation should be done for wedged type of collapse regardless of neurologic status.
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Chiba M, Tang C, Neway WE, Williams TM, Desolms SJ, Dinsmore CJ, Wai JS, Lin JH. P450 interaction with farnesyl-protein transferase inhibitors metabolic stability, inhibitory potency, and P450 binding spectra in human liver microsomes. Biochem Pharmacol 2001; 62:773-6. [PMID: 11551523 DOI: 10.1016/s0006-2952(01)00724-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Methyl substitution at the 2-position of the imidazole ring greatly improved drug metabolism profiles, in human liver microsomes, of ras farnesyl-protein transferase inhibitor (FTI) candidates for drug development. Methyl substitution markedly reduced the P450 inhibitory potency of non-substituted FTIs for CYP3A4 (by a factor of 12-403) and 2C9 (by a factor of 4.2-28), while it had little effect on the CYP2D6 enzyme. An immunochemical inhibition study demonstrated that CYP3A4 plays a predominant role in the metabolism of both non-substituted and 2-methyl-substituted imidazole-containing FTI candidates. Very strong type II binding spectra with human liver microsomes were observed for all non-substituted FTIs, while methyl substitution markedly weakened type II spectra or shifted the type of spectra from II to I. This indicated that methyl substitution on the imidazole moiety interfered with the substrate-P450 heme interaction, likely due to a steric effect caused by the methyl group. A kinetics study revealed that the methyl substitution increased V(max) and K(m) values to the same extent. These studies suggested that the 2-methyl substitution on the imidazole ring improved its drug metabolism profile by reducing the potential to inhibit CYP3A4-mediated metabolism without affecting intrinsic metabolic clearance (V(max)/K(m)).
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Iizuka M, Itou H, Sato M, Yukawa M, Shirasaka T, Chiba M, Watanabe S. Crohn's disease associated with selective immunoglobulin a deficiency. J Gastroenterol Hepatol 2001; 16:951-2. [PMID: 11555120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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Imaizumi T, Honma T, Chiba M, Niwa J, Miyazaki Y. [Risk factor for cerebral hemorrhage for the patient with lacunar infarction: investigation of 5 cases associated with both of symptomatic hemorrhagic and ischemic strokes]. NO TO SHINKEI = BRAIN AND NERVE 2001; 53:737-41. [PMID: 11577415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
BACKGROUND AND PURPOSE Microangiopathy is regarded as an important cause of intracerebral hematoma(ICH) and lacunar infarction. Dot-like low intensity spots on T2-weighted echo planar image(EPI) have been regarded as hemosiderin deposit associated with microangiopathy. However, clinical significance of dot-like hemosiderin spot(dotHS) is still debated. Therefore, we analyzed the number of dotHS on EPI of symptomatic lacunar infarction associated with ICH. METHODS To investigate how the dotHS or risk factors contributed to hemorrhagic strokes for patients with lacunar infarction, the number of dotHS and various risk factors were made a comparison between 20 cases with symptomatic lacunar infarctions(lacunar group) and 5 cases with both symptomatic lacunar infarction and symptomatic ICH(complicated group). In addition to EPI, fluid attenuated inversion recovery image, and T1- and T2-weighted MR images were performed for differential diagnosis of dot HS. RESULTS EPI demonstrated that asymptomatic ICH was significantly more frequent in complicated group (60%) than in lacunar group(10%), and dotHS were significantly more frequent in complicated group(100%) than in lacunar group(50%). The number of dotHS of complicated group was 14.6 +/- 4.3, which was significantly larger than that of lacunar group(4.1 +/- 9.2). No significant difference between two groups were founded in other risk factors including hypertension, diabetes mellitus, hyperlipidemia, and smoking. CONCLUSION These results suggested that dotHS was one of the risk factors for ICH for patients with symptomatic lacunar infarction, and an increasing number of dotHS was one of the predictive factors of symptomatic and/or asymptomatic ICH.
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Hochman JH, Chiba M, Yamazaki M, Tang C, Lin JH. P-glycoprotein-mediated efflux of indinavir metabolites in Caco-2 cells expressing cytochrome P450 3A4. J Pharmacol Exp Ther 2001; 298:323-30. [PMID: 11408558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
The role of P-glycoprotein in secretion of indinavir metabolites produced by CYP3A4 was evaluated in Caco-2 cells expressing CYP3A4. Metabolism of indinavir by CYP3A4 expressing Caco-2 cells grown on filters resulted in the formation of N-dealkylation products (M5 and M6) and hydroxylation of indinavir, which were preferentially secreted into the apical compartment. Apical secretion of the metabolites was inhibited by cyclosporin A (CsA) with all three classes of metabolites showing similar sensitivity to CsA, suggesting that they are all secreted by the same pathway. M6 stimulated P-glycoprotein (Pgp)-ATPase activity in a concentration-dependent manner. This stimulation was inhibited by the Pgp-specific monoclonal antibody C219. A method was developed to specifically inhibit Pgp using the monoclonal antibody UIC2 to determine whether Pgp efflux accounts for a significant proportion of the apical secretion of indinavir metabolites. UIC2 recognizes an extracellular transient conformational epitope that is stabilized by some Pgp substrates or by ATP depletion. Incubation of Caco-2 cells with UIC2 in the presence of 1 microM CsA resulted in 50 to 80% inhibition of Pgp-mediated vinblastine efflux, with no significant inhibition observed by UIC2 or CsA alone. Inhibition of Pgp in CYP3A4-expressing Caco-2 cells by UIC2 and 1 microM CsA resulted in a significant decrease in the apical secretion of M6, M5, and OH-indinavir and an increase in the amount of the metabolites secreted in the basolateral compartment and retained in the cytosol. These results are consistent with a role of Pgp in elimination of CYP3A4-generated metabolites and indicate that even relatively polar metabolites may be secreted from the cell by Pgp.
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Chiba M, Hoshina S, Kono M, Tobita M, Fukushima T, Iizuka M, Watanabe S. Staphylococcus aureus in inflammatory bowel disease. Scand J Gastroenterol 2001; 36:615-20. [PMID: 11424320 DOI: 10.1080/003655201750163079] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND The potential role of superantigens in inflammatory bowel disease (IBD), particularly Crohn disease, has been broached in studies of the functions of T cell receptors. Staphylococcal cells have been found in intestinal lymph follicles of IBDs. To clarify a role of staphylococcal superantigens in IBD, we attempted to determine whether Staphylococcus aureus could be detected in intestinal mucosa, including surgical specimens and lymph follicles of initial cases. METHODS One-hundred-and-six colonic and ileal specimens were obtained from 38 Crohn disease, 25 ulcerative colitis and 36 non-IBD patients through therapeutic surgery or endoscopic biopsy. In Crohn disease, 23 surgical specimens and 11 biopsy specimens from initial cases were included. DNA was extracted with phenol-chloroform after homogenization and proteinase K treatment in 73 mucosal specimens. Using an inverted microscope, lymph follicle tissue was microdissected from the remaining 33, mostly biopsy, specimens. DNA was then extracted by freeze-thawing. A coagulase gene characteristic of S. aureus was sought. A nested polymerase chain reaction was performed utilizing primers that amplify a region of the coagulase gene. Polymerase chain reaction products were analyzed with polyacrylamide gel electrophoresis. RESULTS Only one surgically resected colonic specimen, from a 42-year-old male ulcerative colitis patient, registered positive staphylocoagulase amplification. CONCLUSIONS Staphylococcal superantigens are not involved in either the early lesions or the established lesions of Crohn disease. However, S. aureus infection occasionally may occur during the course of IBD.
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Abe E, Kobayashi T, Murai H, Suzuki T, Chiba M, Okuyama K. Total spondylectomy for primary malignant, aggressive benign, and solitary metastatic bone tumors of the thoracolumbar spine. JOURNAL OF SPINAL DISORDERS 2001; 14:237-46. [PMID: 11389375 DOI: 10.1097/00002517-200106000-00009] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The records of 14 patients with malignant or aggressive benign vertebral tumors of the thoracolumbar spine who underwent total spondylectomy (TS) were evaluated retrospectively. Total spondylectomy was performed by bisecting the affected vertebra through the pedicle using fine threadwire saws and removing the vertebra en bloc through the posterior procedure alone or the one-stage anteroposterior combined procedure. Remarkable pain relief and ambulation after surgery were achieved in all 14 patients. No serious complications occurred. Nerve roots were sacrificed in seven cases. A marginal surgical margin was achieved in 10 cases and an intralesional surgical margin was achieved in four. At the site of the osteotomized pedicle, the surgical margin was marginal, with the possibility of tumor-cell contamination in 10 cases. Local recurrence was found in three cases of posterior total spondylectomy at 0.3 to 3.5 years (mean, 3.2 years) follow-up evaluation at the other site of the osteotomized pedicle. These results suggest that this type of total spondylectomy is effective in controlling local recurrence without incurring major complications and is a clinically useful procedure.
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Iizuka M, Saito H, Yukawa M, Itou H, Shirasaka T, Chiba M, Fukushima T, Watanabe S. No evidence of persistent mumps virus infection in inflammatory bowel disease. Gut 2001; 48:637-41. [PMID: 11302960 PMCID: PMC1728269 DOI: 10.1136/gut.48.5.637] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
BACKGROUND AND AIM There is controversy regarding whether paramyxovirus infection is causally associated with inflammatory bowel disease (IBD). The latest cohort study claimed that atypical measles and mumps infections in childhood may be risk factors for later IBD. This study was conducted to clarify the validity of a causal link between persistent mumps virus infection and IBD. SUBJECTS AND METHODS (1) Amplification of the mumps virus genome was performed in both intestinal specimens (ulcerative colitis 15, Crohn's disease 15, control 10) and peripheral blood lymphocytes (PBL) (ulcerative colitis seven, Crohn's disease six, control three) by reverse transcription-polymerase chain reaction (RT-PCR) followed by Southern hybridisation using primers specific to the viral genome encoding phosphoprotein or haemagglutinin-neuraminidase. (2) Titre of serum antimumps IgG was measured in 16 patients with ulcerative colitis, in 16 patients with Crohn's disease, and in 16 normal controls using an enzyme linked immunosorbent assay. RESULTS (1) The mumps virus genome was not detected by RT-PCR in intestinal specimens or PBL in any case. (2) Antimumps IgG titre was positive in 7/16 ulcerative colitis, 10/16 Crohn's disease, and 11/16 control specimens. The mean (SEM) titre of antimumps IgG was 12.281 (7.831) in ulcerative colitis, 7.675 (1.608) in Crohn's disease, and 8.637 (1.969) in controls, with no significant difference between the three groups. CONCLUSION We could not find any evidence to support a causal link between persistent mumps virus infection and IBD.
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Sanada Y, Yosizawa Y, Chiba M. [Nutritional support in children with cancer]. NIHON RINSHO. JAPANESE JOURNAL OF CLINICAL MEDICINE 2001; 59 Suppl 5:812-4. [PMID: 11439656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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