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T Ohba

Publications and source records attributed to T Ohba.

At least 37 records · Page 2Linked to original sources
PubMed2001

The liquid-state 31P-nuclear magnetic resonance study on microfiltrated milk.

To gain further insight into diversiform phosphorus in bovine milk, we separated skim milk into casein micelle and serum fractions by microfiltration and subjected them to liquid-state 31P-nuclear magnetic resonance (NMR) spectroscopy. As previously reported, the skim milk spectrum showed a broad and indistinct peak from phosphoserine residue (SerP) of casein. In the casein micelle spectrum, however, the SerP peak was more clearly observed with a phosphate peak that may be from micellar calcium phosphate (MCP). The serum spectrum was the same as skim milk spectrum, except for SerP peak. Furthermore, two types of casein micelle fractions, with 0.90 and 1.04 of [beta-casein + kappa-casein]/[alpha(s1)-casein + alpha(s2)-casein] ratios were generated by different temperature microfiltrations, occurring because beta-casein is released from the micelle at a low temperature. The shape of SerP peaks changed dramatically in both the casein micelle spectra, when the temperature dropped from 35 to 5 degrees C. Deconvolution analysis indicated that each SerP peak comprised the same set of four peaks. Half-width and composition discriminated between the two types of casein micelle fractions. As a consequence, there was significant interaction between casein micelle and milk serum, causing cloudiness of SerP in the liquid-state 31P-NMR spectrum of milk. Casein composition influenced the SerP-MCP interaction in micellar structure. Shape changing of the SerP peak was discussed in connection with beta-casein-release phenomenon.

Animals↗
PubMed2000

Synthesis of mRNAs for cathepsins L and K during development of the rat mandibular condylar cartilage.

Cathepsins are cysteine proteinase family members which are known to degrade proteoglycan and collagen, components of several extracellular matrices. Their functions in the condylar cartilage during skeletal development have not yet been fully clarified. In this study, we investigated the mRNA expression of cathepsins L and K in the growing rat mandibular condylar cartilage, as compared to that in the rat long bone cartilage, by in situ hybridization, reverse transcription polymerase chain reaction (RT-PCR) and Southern blotting analysis. In the condylar cartilage, cathepsin L mRNA expression was widely observed throughout the zones of maturative and hypertrophic chondrocytes at embryonic day (E) 17 and postnatal day (P) 1. The signal was restricted to maturative and upper hypertrophic chondrocytes at P7, and finally it became undetectable by P28. In the long bone cartilage, cathepsin L was not expressed in the chondrocytes at any stage. Cathepsin K mRNA was not, however, detected either in the mandibular condylar cartilage cells or in the long bone cartilage cells but it was selectively detected in osteoclasts in calcified cartilage and bone in both tissues. RT-PCR also showed a similar mRNA expression pattern of cathepsins L and K. These results indicate that cathepsins L and K may be involved in the skeletal development of both the long bone and the mandibular condyle. Furthermore, cathepsin L may play an important role in the degradation of the cartilaginous extracellular matrix in maturative and hypertrophic cell layers during successive developmental stages of the mandibular condyle.

Animals↗
PubMed2000

Upregulation of the expression of Fas antigen and Fas ligand in a human submandibular gland ductal cell line by okadaic acid.

Fas receptor is a member of a superfamily of receptors characterized by cysteine-rich motifs in the extracellular domain of the molecule. Binding of Fas ligand to the receptor leads to receptor activation and the induction of intracellular signals that result in apoptotic cell death. In the present study, the expression of mRNA and proteins of Fas receptor and Fas ligand were examined in human submandibular gland ductal (HSG) cells treated with okadaic acid by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunoblot analysis. Six hundred and eighty-two bp of the PCR product of Fas receptor mRNA was detected in HSG cells and a protein with an estimated molecular weight of 58,000 was expressed in HSG cells. Treatment of HSG cells with an agonistic anti-Fas monoclonal antibody resulted in death of HSG cells, indicating that the functional Fas receptor protein is expressed in HSG cells. Fas receptor protein expression stimulated by okadaic acid was elevated in a dose- and time-dependent manner, with maximal expression at 20 nM and 48 h treatment. Fas ligand mRNA was also detected constitutively in HSG cells by RT-PCR. Okadaic acid stimulated the expression of Fas ligand protein in HSG cells in a time-dependent manner, while the expression of the ligand was low in untreated HSG cells. The molecular weight of Fas ligand was estimated as 68,000. An antagonistic anti-Fas ligand monoclonal antibody prevented okadaic acid-induced death in HSG cells in a dose-dependent fashion as determined by WST-1 assay. The results indicate that the expression of Fas receptor and ligand is regulated by protein phosphatase(s) sensitive to okadaic acid and is involved in okadaic acid-induced apoptosis in HSG cells. The results also suggest that the Fas receptor-ligand system might regulate apoptosis in HSG cells.

Antibodies, Monoclonal↗
PubMed2000

Expression of cathepsin K mRNA during experimental tooth movement in rat as revealed by in situ hybridization.

The expression of cathepsin K. a novel collagenolytic enzyme specifically expressed in osteoclasts, was investigated in the rat maxillary dentoalveolar unit during experimental tooth movement by in situ hybridization histochemistry with a non-radioisotopic cRNA probe for rat cathepsin K. Orthodontic elastics were inserted into the interproximal space between the maxillary first and second molars of 7-week-old male SD rats according to Waldo's method and sections prepared from tissues obtained at 12 hr, 1, 2, 3, 4, 7, and 12 days after orthodontic force application. Cathepsin K mRNA expression was detected in the mono- and multinuclear osteoclasts on the pressure side of the alveolar bone at 12 hr after force application, and the distribution and number of cathepsin K mRNA-positive osteoclasts increased time-dependently on the pressure side. At 3-4 days, a marked increase in cathepsin K mRNA-positive osteoclasts was found not only on the pressure side but also on the tension side of the alveolar bone in response to tooth movement. At 7-12 days, the cathepsin K mRNA-positive osteoclasts on both sides had disappeared. These findings suggest that the recruitment of osteoclasts on the pressure side begins during the initial stage of orthodontic tooth movement and the site-specific early induction of cathepsin K mRNA may cause an imbalance in the relative resorption activities on the pressure and tension side incident to such movement.

Alveolar Process↗
PubMed2000

Comparison of the panoramic radiographic and CT features of post-Caldwell-Luc maxillary sinuses.

OBJECTIVE: To clarify the panoramic radiographic features of the post-Caldwell-Luc maxillary sinus. METHODS: The panoramic radiographs were compared with the axial CT scans of 48 symptomatic post-Caldwell-Luc maxillary sinuses which had been operated on more than 5 years previously. RESULTS: The two characteristic features of the post-Caldwell-Luc maxillary sinus on panoramic radiographs were a right-angled triangular shape, due to absence of the floor of the maxillary sinus and radiopacity of the posterior wall and zygomatic bone, and an ill-defied panoramic innominate line. This shape was related to the finding of a contracted sinus with a radiolucent lumen on the CT scans. There was also close relationship between the ill-defined panoramic innominate line and thickened posterior wall on the CT scans. CONCLUSION: The characteristic features of the post-Caldwell-Luc maxillary sinus on panoramic radiographs were a right-angled triangular shape and an ill-defined panoramic innominate line. These features were related to a contracted sinus and a thickened posterior wall on the CT scans.

Adult↗
PubMed2000

The molar vesicle fluid contains the beta-core fragment of human chorionic gonadotropin.

The human chorionic gonadotropin (hCG) beta-core fragment (beta-CF) is a major molecular form of hCG beta subunit (hCGbeta) immunoreactivity in the urine of pregnant women and patients with trophoblastic disease. The majority of evidence supports the fact that the beta-CF is a degradative product of intact hCG and free hCGbeta in the kidneys. We found a beta-CF-like substance in the fluid of molar vesicles from a patient with complete hydatidiform mole. The molar fluid beta-CF (mbeta-CF) was indistinguishable from the beta-CF in the patient's urine (ubeta-CF) by immunoreactivity and by elution profile on gel chromatography. The binding study to lectins, however, showed that mbeta-CF contains a carbohydrate moiety that differs from that of ubeta-CF. Immunohistochemistry with anti-beta-CF antibody demonstrated a strong immunoreactivity in a large number of macrophages in the molar villous stroma. In vitro incubation of intact hCG with peritoneal macrophages showed a slow increase of intact hCG in the cell cytosol with the appearance of beta-CF-like substance in the cell supernatant. In conclusion, the source of beta-CF in molar fluid is likely to be macrophages existing in the villous stroma. Thus macrophages may ingest intact hCG and act as a local regulator of gonadotropic hormones.

Body Fluids↗
PubMed2000

Expression of cyclooxygenase 2 by prostaglandin E(2) in human endometrial adenocarcinoma cell line HEC-1B.

The regulation of expression of cyclooxygenase 2 (COX-2) was investigated by treatment with PGE(2) in human endometrial adenocarcinoma cell line HEC-1B. One microM PGE(2) could stimulate the expression of COX-2 approximately twofold in this cell line. The same concentration of PGE(2) also stimulated activation of mitogen-activated protein kinase (MAP kinase) and protein kinase B (PKB). PGE(2)-induced MAP kinase activation was sensitive to a MAP kinase kinase (MEK) inhibitor, PD098059, and a protein kinase A inhibitor, H-89. PD098059 and H-89 also partially inhibited the expression of COX-2 stimulated by PGE(2). PGE(2) could stimulate the activation of PKB, which was sensitive to phosphatidylinositol-3-OH kinase (PI3K) inhibitor, wortmannin. Whereas wortmannin alone partially inhibited the expression of COX-2, a combination of wortmannin and PD098059 totally inhibited PGE(2)-mediated COX-2 expression. These results suggest that MAP kinase and PI3K pathways are stimulated with PGE(2), and that both of these pathways are involved in the expression of COX-2. In addition, they also suggest that protein kinase A remains upstream of PGE(2)-induced activation of MAP kinase in HEC-1B cells.

Adenocarcinoma↗
PubMed2000

Quantitative radiographic changes in the mandible and the tibia in systemically loaded rats fed a low-calcium diet.

The combined effect of the duration of loaded physical exercise and the percentage of calcium intake on the mandible and tibia were studied in developing male rats. For the loaded exercise, rats ran on a treadmill at a rate of 12 m per min for either 1 or 2 h per day. A total of 54 4-week-old male Wistar rats were randomly assigned to one of six groups. After 4 weeks of the diet and loaded exercise, the rats were killed and their mandibles and tibia were removed. Each individual bone was assessed by radiography and the radiographs were then used for measurements of cortical thickness, bone length and bone width. All radiographic images were analyzed using a computer-based scanner image analysis system. In addition, we measured the dry weight both of the tibia and mandible. The results demonstrated that significant differences in cortical thickness, bone length, bone width, and bone weight, both of the tibia and the mandible, were detectable between the normal diet group and the low-calcium diet group. Among the normal diet groups, significant differences were found in cortical thickness, bone length, bone width, and bone weight of the tibia, whereas no significant differences in either cortical bone thickness, bone length or bone weight of the mandible were detected. In contrast, among the low-calcium diet groups, no significant differences were detected in cortical thickness, bone length, bone width or bone weight for either the tibia or the mandible. Our results suggested that systemic exercise, such as running, promote the linear dimensions and the cortical thickness of the tibia in response to local stimuli. Furthermore, sufficient calcium intake appears to be necessary to allow the effect of systemic exercise on tibial bone growth to occur. In contrast, systemic loaded exercise does not promote either bone growth or development of the mandible even under conditions of sufficient calcium intake.

Animals↗
PubMed2000

Normal fetal brain development: MR imaging with a half-Fourier rapid acquisition with relaxation enhancement sequence.

PURPOSE: To analyze normal maturation of the fetal brain with half-Fourier rapid acquisition with relaxation enhancement (RARE) magnetic resonance (MR) imaging. MATERIALS AND METHODS: The normal brains of 25 fetuses of 12-38 weeks gestational age were examined in utero with half-Fourier RARE imaging. Gyrus maturation, gray and white matter differentiation, ventricle-to-brain diameter ratio, and subarachnoid space size were evaluated with respect to gestational age. RESULTS: At 12-23 weeks, the brain had a smooth surface, and two or three layers were differentiated in the cerebral cortex. At 24-26 weeks, only a few shallow grooves were seen in the central sulcus, and three layers, including the immature cortex, intermediate zone, and germinal matrix, were differentiated in all fetuses. At 27-29 weeks, sulcus formation was observed in various regions of the brain parenchyma, and the germinal matrix became invisible. Sulcation was seen in the whole cerebral cortex from 30 weeks on. However, the cortex did not undergo infolding, and opercular formation was not seen before 33 weeks. At 23 weeks and earlier, the cerebral ventricles were large; thereafter, they gradually became smaller. The subarachnoid space overlying the cortical convexities was slightly dilated at all gestational ages, most markedly at 21-26 weeks. CONCLUSION: Changes in brain maturation proceed through stages in an orderly and predictable fashion and can be evaluated reliably with half-Fourier RARE MR imaging.

Brain↗
PubMed2000

On-line measurement of intracellular ATP of Saccharomyces cerevisiae and pyruvate during sake mashing.

The concentrations of intracellular ATP of Saccharomyces cerevisiae and pyruvate in a medium were instantaneously increased by pulse addition of glucose during starvation. They were reduced rapidly by alcohol fortification of the medium, accompanied by simultaneous increases of acetaldehyde concentration and inviability of yeast cells. These results were monitored during fermentation of sake mash by an on-line measuring method. Intracellular ATP and pyruvate concentrations were considered to be indicators of the physiological state of the yeast in sake mash. During sake mashing, it was observed that an increase in temperature enhanced the intracellular ATP concentration and the pyruvate production of the yeast. Since pyruvate production was not affected intensely by changes in temperature during cultivation in a glucose-limited chemostat, this effect was thought to be due to the enhanced rates of cell-growth and/or alcohol production. This suggests that the control of mashing temperature during cell growth until about 10% alcohol accumulation is achieved is important for the control of the pyruvate concentration in sake mash.

Journal Article↗
PubMed1999

Self-organization of microtubule asters induced in Xenopus egg extracts by GTP-bound Ran.

The nucleotide exchange activity of RCC1, the only known nucleotide exchange factor for Ran, a Ras-like small guanosine triphosphatase, was required for microtubule aster formation with or without demembranated sperm in Xenopus egg extracts arrested in meiosis II. Consistently, in the RCC1-depleted egg extracts, Ran guanosine triphosphate (RanGTP), but not Ran guanosine diphosphate (RanGDP), induced self-organization of microtubule asters, and the process required the activity of dynein. Thus, Ran was shown to regulate formation of the microtubule network.

Animals↗
PubMed1999

Inhibitors of protein synthesis and RNA synthesis protect against okadaic acid-induced apoptosis in human osteosarcoma cell line MG63 cells but not in Saos-2 cells.

In a previous study, we demonstrated that the protein phosphatase inhibitors, okadaic acid and calyculin A, induced apoptosis in human osteosarcoma cell lines, Saos-2 and MG63 cells. In the present study, to determine if new gene transcription and protein synthesis are required for okadaic acid-induced apoptosis in Saos-2 and MG63 cells, the cells were treated for 48h with varying concentrations of the inhibitors of protein or RNA synthesis, i.e., cycloheximide, actinomycin D, and puromycin, in the presence of a fixed dose of okadaic acid. All these reagents in different concentrations prevented the okadaic acid-induced apoptosis in MG63 cells in a dose-dependent fashion. The same concentrations of cycloheximide, actinomycin D, or puromycin alone did not induce any apoptotic features in MG63 cells. However, not all the aforementioned reagents affected okadaic acid-induced apoptosis in Saos-2 cells. Okadaic acid-induced and cycloheximide-prevented apoptosis was shown by phase-contrast microscopy, WST-1 assay, direct visualization of nuclear condensation and fragmentation of chromatin, and the characteristic DNA ladder formation on agarose gel electrophoresis. The present results indicate that the induction of new cell death genes and ongoing protein synthesis may have a role in okadaic acid-induced apoptosis in MG63 cells and that such proteins are not required in Saos-2 cells.

Apoptosis↗
PubMed1999

A novel panoramic machine for photofluorography.

OBJECTIVE: To describe the main features of a prototype panoramic X-ray machine modified for photofluorography. METHODS: The prototype PTM 2001 (Asahi Roentgen, Kyoto, Japan) consists of a conventional panoramic machine with a modified X-ray generator and incorporating a 9-inch image intensifier and a photofluorographic camera. RESULTS: The photofluorographic panoramic radiograph is reduced in size by 60% compared with conventional images. Using 10 cm x 45.7 m photoradiographic film 250 panoramic images can be continuously obtained. Examination time is shorter since cassette changes are not necessary. The radiation dose-in-air, measured in front of the secondary collimator, is 174 muGy. CONCLUSIONS: The advantages of the photofluorographic panoramic radiography include cost economy, shorter examination time and lower radiation exposure.

Equipment Design↗
PubMed1999

The protein phosphatase inhibitors, okadaic acid and calyculin A, induce apoptosis in human submandibular gland ductal cell line HSG cells.

OBJECTIVE: To investigate a possible relationship between protein phosphorylation or dephosphorylation status and apoptosis in salivary gland cells, we examined the effects of okadaic acid and calyculin A, the protein phosphatase inhibitors, on cultured human submandibular gland ductal cell line, HSG cells. METHODS: HSG cells at subconfluent stages were exposed to varying concentrations of okadaic acid or calyculin A. Apoptoses were analysed in HSG cells by phase-contrast microscopy, WST-1 cytotoxicity assay, Hoechst 33342 staining, and DNA ladder formation. RESULT: Both okadaic acid and calyculin A induced cell death in HSG cells in a dose-dependent fashion. Marked nuclear condensation and fragmentation of chromatin was observed in HSG cells. DNA ladder formation was also detected in HSG cells by treatment with okadaic acid or calyculin A. The induced DNA ladder formation was dose-dependent with maximal effect at concentrations of 50 nM okadaic acid and 2 nM calyculin A, respectively, and were time-dependent from 14 h to 48 h. To further determine if new gene transcription and protein synthesis regulate okadaic acid-induced apoptosis in HSG cells, the cells were treated with cycloheximide or actinomycin D in the presence of 20 nM okadaic acid. Neither inhibitor protected the cells against okadaic acid-induced apoptosis. CONCLUSION: Based on the known selectivity of okadaic acid and calyculin A, our results indicate that the pathway of the apoptosis in the cultured salivary gland cells is regulated by protein phosphatase type 1 or type 2A. Our results also suggest that new protein synthesis and/or mRNA expression are not involved in okadaic acid-induced apoptosis in HSG cells.

Apoptosis↗
PubMed1999

Extracts of Actinobacillus actinomycetemcomitans induce apoptotic cell death in human osteoblastic MG63 cells.

Whether an extracellular component of periodontal-disease-causing bacteria induces apoptotic cell death in bone-related cells is unknown. To study the effects on osteoblasts of extracts obtained from sonicated Actinobacillus actinomycetemcomitans and Prevotella intermedia, we cultured human osteoblastic cell lines MG63 and Saos-2 cells and mouse osteoblastic cell line MC3T3-E1 cells in the presence of such extracts. The addition of the extracts from Actinobacillus actinomycetemcomitans induced cell death in MG63 cells in a dose- and time-dependent fashion over the concentration range of 0.1 to 10 microg/mL. By contrast, the extracts from Prevotella intermedia did not induce cell death in these cells, even in the presence of 10 microg/mL protein. By using the Hoechst 33342 staining technique, we observed marked nuclear condensation and fragmentation of chromatin in MG63 cells treated with the extracts of Actinobacillus actinomycetemcomitans. DNA ladder formation, a hallmark of apoptosis, also was detected in MG63 cells treated with extracts from Actinobacillus actinomycetemcomitans. In MG63 cells, DNA ladder formation was dose-dependent, with a maximal effect at a concentration of 10 microg/mL, and time-dependent, from 12 to 48 hrs. However, the extracts from Prevotella intermedia did not induce DNA fragmentation in MG63, Saos-2, or MC3T3-E1 cells. The extracts from Actinobacillus actinomycetemcomitans did not induce cell death and DNA fragmentation in Saos-2 and MC3T3-E1 cells. Sonicated extracts of Actinobacillus actinomycetemcomitans that had been treated with heat and trypsin did not induce DNA ladder formation in MG63 cells, suggesting that the apoptosis-inducing factors are proteinaceous. Cycloheximide prevented the Actinobacillus actinomycetemcomitans-induced DNA ladder formation in MG63 cells in a dose-dependent fashion, suggesting that new gene transcription and protein synthesis are regulated for Actinobacillus actinomycetemcomitans-induced apoptosis in MG63 cells. Our results indicate that apoptosis in alveolar bone cells induced by Actinobacillus actinomycetemcomitans plays an important role in periodontal diseases.

3T3 Cells↗