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H Hagiwara

Publications and source records attributed to H Hagiwara.

At least 55 records · Page 3Linked to original sources
PubMed2000

Vasoactive peptide-regulated gene expression during osteoblastic differentiation.

The formation of bone occurs via a series of events that are regulated by various hormones and cytokines. We previously reported that endothelin (ET) inhibits the mineralization by osteoblastic cells and natriuretic peptide (NP) promotes osteoblastic differentiation. Therefore, we attempted to identify the genes induced by ET or NP in mouse preosteoblastic MC3T3-E1 cells using the method known as differential display-polymerase chain reaction (DD-PCR) to understand the bone metabolism further. Consequently, we found that expression levels of mRNAs for fibronectin, type XII collagen, p160 Rho-associated kinase (ROCK), caldesmon, calpain, nucleolin and a novel gene with a zinc finger motif are downregulated in osteoblasts by ET stimuli. We also found that expression levels of mRNAs for eIF-4A and a novel gene are increased by C-type natriuretic peptide (CNP) stimuli.

Animals↗
PubMed2000

A novel TATA-binding protein-binding protein, ABT1, activates basal transcription and has a yeast homolog that is essential for growth.

Identification of a novel mouse nuclear protein termed activator of basal transcription 1 (mABT1) that associates with the TATA-binding protein (TBP) and enhances basal transcription activity of class II promoters is described. We also identify mABT1 homologous counterparts in Caenorhabditis elegans and Saccharomyces cerevisiae and show the homologous yeast gene to be essential for growth. The mABT1 associated with TBP in HeLa nuclear extracts and with purified mouse TBP in vitro. In addition, ectopically expressed mABT1 was coimmunoprecipitated with endogenous TBP in transfected cells. More importantly, mABT1 significantly enhanced transcription from an adenovirus major late promoter in a reconstituted cell-free system. We furthermore demonstrate that mABT1 consistently enhanced transcription from a reporter gene with a minimal core promoter as well as from reporter genes with various enhancer elements in a cotransfection assay. Taken together, these results suggest that mABT1 is a novel TBP-binding protein which can function as a basal transcription activator.

Amino Acid Sequence↗
PubMed2000

Role of ascorbic acid in the osteoclast formation: induction of osteoclast differentiation factor with formation of the extracellular collagen matrix.

Osteoclasts are bone-resorbing multinucleated cells. Tartrate-resistant acid phosphatase-positive (TRAP-positive) mononuclear and multinucleated cells, which are osteoclast-like cells (OCLs), were formed as a result of the coculture of mouse bone marrow cells and clonal stromal ST2 cells in the presence of 1alpha,25-dihydroxy-vitamin D3. Removal of ascorbic acid from the culture medium prevented the formation of TRAP-positive OCLs. Addition of ascorbic acid to the medium formed TRAP-positive OCLs, and the effect of ascorbic acid was dose-dependent. When we examined the level of messenger RNA (mRNA) for osteoclast differentiation factor (RANKL/ODF) in ST2 cells, we found that ascorbic acid caused an approximately 5-fold increase in the level of this mRNA. The half-life of the mRNA was unaffected by ascorbic acid. To characterize the mechanism of action of ascorbic acid, we investigated the relationship between formation of TRAP-positive OCLs and formation of the collagen matrix. Inhibitors of the formation of collagen triple helices blocked both the formation of TRAP-positive OCLs and the expression of the mRNA for RANKL/ODF in response to ascorbic acid. Our findings suggest that ascorbic acid might be essential for osteoclastogenesis and might induce the formation of TRAP-positive OCLs via induction of the synthesis of RANKL/ODF that is somehow mediated by the extracellular matrix.

Animals↗
PubMed2000

Labyrinthine involvement and multiple perforations of the tympanic membrane in acute otitis media due to group A streptococci.

We present here three cases of acute otitis media caused by a virulent group A streptococcal infection that rapidly led to deterioration in hearing. Two of the three cases presented with severe sensorineural and mixed hearing loss with multiple tympanic membrane perforations, and the third presented with severe bilateral sensorineural hearing loss following acute otitis media involving group A streptococci. All patients were treated with systemic (piperacillin) and topical antibiotics (ofloxacin ear drops): one patient also received a systemic steroid (betamethasone). Deafness persisted in one patient but in the other two, hearing gradually recovered. Severe cytotoxicity was considered to have occurred in all patients, resulting in multiple perforations of the tympanic membrane and necrosis in the middle ear.

Adult↗
PubMed2000

[A case report of Binswanger type encephalopathy manifested after coronary artery bypass grafting].

A 68-year-old man showed signs of dementia after undergoing triple CABG with cardiopulmonary bypass. Brain CT revealed widespread atrophy and lucency in white matter without any sign of stroke. No critical stenosis in cervical vessels was found in duplex scanning. He kept politeness well, but had severe memory impairment. These findings were characteristic of Binswanger type encephalopathy which must have been latent preoperatively. This disease is caused by ischemic damage in brain stem and white matter due mainly to atherosclerotic micro cerebrovasculopathy, and highly related to hypertension. We have to be aware of intracranial cerebrovascular disease when assessing the risk of brain damage in candidates for CABG.

Aged↗
PubMed2000

[A case of callosal apraxia without agraphia and acquired stuttering associated with callosal infarction].

We report a 52-year-old right-handed man with cerebral infarction of the right anterior cerebral artery area. The MRI findings showed cerebral infarction in the trunk of the right corpus callosum, although some part of the posterior half of the trunk was spared. Some part of right precuneal gyrus, cingulate gyrus were also involved. The clinical feature of this case is characterized by following two points. First, although callosal apraxia is usually accompanied by agraphia, he showed apraxia with the left hand, but showed no agraphia. Secondary, he showed speech dysfluency mainly characterized by initial syllable repetitions. The nature of this speech dysfluency was determined as acquired stuttering. This case suggests that the pathway for praxis locates distinct portion from that for writing on corpus callosum. We analyzed callosal lesions of previous studies reporting callosal apraxia without agraphia, then compared to that of this case. And we also reviewed acquired stuttering report caused by callosal lesions. Consequently, we suggest that apraxia and stuttering were caused by damage of the trunk of the corpus callosum. While writing was preserved by the intact fibers in the posterior half of the trunk.

Apraxias↗
PubMed2000

Effect of exercise training on ANP receptors.

To clarify whether exercise-training affects ANP function, we trained male Wistar rats by treadmill running for nine weeks and measured ANP receptor number and affinity in the kidney, lung and adrenal. We also measured guanylate cyclase activity, by which second messenger cGMP accumulates. The number of adrenal ANP receptor significantly increased after exercise-training. There was no significant difference of affinity for all the organs examined between the training group and the control group. Guanylate cyclase activity tended to decrease in the kidney in the training group. A significant difference was found when the samples were stimulated by C-type natriuretic peptide (CNP). There was no significant difference in guanylate cyclase activity in the lung and adrenal. These findings are consistent with the exercise-induced hypervolemia, but not with the anti-hypertensive role of exercise-training.

Adrenal Glands↗
PubMed2000

Deafness genes.

The pathophysiology of sensorineural hearing impairment, which is a common clinical disorder, remains yet to be determined. For prelingual hearing loss, epidemiological data show that 1 neonate in 1,000 is born with severe to profound hearing loss, and in half of that number the loss is inherited. Some genes responsible for sensorineural hearing impairment have been cloned during the last several years, and the underlying mechanisms causing hearing impairment have begun to be clarified with the advent of recent developments in molecular genetics. Cases of non-syndromic deafness are classified by the mode of inheritance (DFNA, dominant; DFNB, recessive; DFN, X-linked), with the loci being numbered in the order of discovery. To date, 31 autosomal dominant, 28 autosomal recessive, and 6 X-linked non-syndromic sensorineural hearing impairment loci have been mapped, and 17genes have been cloned (Hereditary Hearing Loss Homepage, http://danallab-www.uia.ac.be.dnalab/hhh/). We have identified mutations in four of those 17 deafness genes in Japanese families. Clinical and genetic findings of the above disorders are reviewed.

Adolescent↗
PubMed1999

Effects of nicotine on cultured cells suggest that it can influence the formation and resorption of bone.

The acute effects of nicotine [1-methyl-2-(3-pyridyl)pyrrolidine] on the formation and resorption of bone were examined in cultures of clonal rat calvarial osteogenic cells (ROB-C26) and clonal mouse calvarial preosteoblastic cells (MC3T3-E1), as well as in osteoclast-like cells formed during coculture of mouse bone marrow cells and clonal stromal cells from mouse bone marrow, ST2 cells, at concentrations that occur in the saliva of smokeless tobacco users. Nicotine stimulated the rate of deposition of Ca(2+) by ROB-C26 cells, as well as the alkaline phosphatase activity of these cells, in a dose-dependent manner. However, both activities decreased in MC3T3-E1 cells that had been exposed to nicotine. These results indicate that nicotine affected osteoblastic differentiation in osteoblast-like cells. By contrast, nicotine reduced, in a dose-dependent manner, the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells (MNCs) and the formation of pits on slices of dentine, both of which are typical characteristics of osteoclasts. Our results suggest that nicotine might have critical effects on bone metabolism.

Alkaline Phosphatase↗
PubMed1999

Cross-linking of plasmalemmal cholesterol in lymphocytes induces capping, membrane shedding, and endocytosis through coated pits.

By use of a nicked and biotinylated perfringolysin O (BCtheta), which binds to cholesterol specifically, we studied consequences of cross-linking cholesterol in lymphocytes. When bound with BCtheta and then with labeled avidin or streptavidin, capping occurred in most cells within 30 min at 37 degrees C. It was inhibited by cytochalasin D or NaN3, but not by nocodazole. When BCtheta-cholesterol was capped, Thy-1 and transferrin receptor, a GPI-anchored protein and a transmembrane protein, respectively, remained evenly distributed. By fluorescence and electron microscopy, a cluster of small vesicles bound with BCtheta were observed in the cap. They were then shed in the medium or internalized through coated pits. The result indicates that cross-linking of cholesterol in lymphocytes induces capping, but does not affect distribution of membrane proteins, and that the capped cholesterol molecules are either shed as vesicles or endocytosed.

Animals↗
PubMed1999

Guaianolides as immunomodulators. Synthesis and biological activities of dehydrocostus lactone, mokko lactone, eremanthin, and their derivatives.

The naturally occurring guaianolides, namely mokko lactone (1), dehydrocostus lactone (2), eremanthin (3), and related guaianolides, 16, 17, 21, 22, 28-31, 33, 36, 37, and 39, have been synthesized starting from l-alpha-santonin in an effort to examine their structure-activity relationship as inhibitors of the killing function of cytotoxic T lymphocytes (CTL) and the induction of intercellular adhesion molecule-1 (ICAM-1). It was observed during the present study that the guaianolides possessing an alpha-methylene gamma-lactone moiety, i.e., 2, 3, 30, 33, 37, and 39, exhibited significant inhibitory activity toward the killing function of CTL and the induction of ICAM-1.

Adjuvants, Immunologic↗
PubMed1999

Influence of transfusion-transmitted virus infection on the clinical features and response to interferon therapy in Japanese patients with chronic hepatitis C.

Recently, the genome of a novel DNA virus, transfusion-transmitted virus (TTV), was cloned from the plasma of a blood donor who had an elevated aminotransferase level but no serological markers of known hepatitis viruses. In this study, we investigated the influence of TTV infection on the clinical features and response to interferon (IFN) therapy in patients with chronic hepatitis C. We studied 247 patients who had received a 16- or a 24-week course of IFN-alpha therapy. The serum of these patients was analysed for TTV DNA using a hemi-nested polymerase chain reaction and TTV was detected in 114 patients (46%). No significant differences were found with respect to clinical features (gender, age, liver-related biochemical tests, hepatitis C virus (HCV) genotype and serum HCV RNA levels) between the patients who were positive for TTV DNA and those who were negative for TTV DNA. The fibrosis score was higher in TTV-positive patients (2.1 +/- 1.1) than in TTV-negative patients (1.7 +/- 1.1, P = 0.023). The biochemical sustained-response rate was 25% in TTV-positive patients and 25% in TTV-negative patients (not significant). A sustained HCV clearance rate was achieved in 26% of TTV-positive patients and in 22% of TTV-negative patients (not significant). TTV DNA clearance after IFN therapy was observed in 36 of 69 patients (52%) for whom stored serum samples were available. The disappearance of TTV DNA had no effect on the biochemical response to IFN therapy. In conclusion, TTV co-infection is frequently observed in Japanese patients with chronic hepatitis C. In chronic hepatitis C, TTV does not modify the clinical features or the response to IFN.

Adolescent↗
PubMed1999

Correlation between induction of expression of biglycan and mineralization by C-type natriuretic peptide in osteoblastic cells.

We reported previously that C-type natriuretic peptide (CNP) promotes the differentiation and mineralization of osteoblastic cells [Am. J. Physiol. 270 (Cell Physiol. 39): C1311-C1318, 1996]. However, little information is available about the mechanism of action of CNP in differentiating osteoblastic cells. Using the technique known as differential display-polymerase chain reaction, we attempted to identify the mRNAs whose levels are regulated by CNP in mouse clonal preosteoblastic MC3T3-E1 cells. One species of mRNA whose level was increased by CNP was 99% homologous to the 3'-untranslated region of a mouse gene for biglycan (BGN), a small proteoglycan. BGN is known to be involved in bone formation by osteoblastic cells. Therefore, we investigated the relationship, during the formation of mineralized nodules, between CNP and BGN using calvarial osteoblast-like cells (ROB cells) from newborn rats, that are a good model for studies on bone formation in vitro. Northern blot analysis revealed that transcription of the mRNA for BGN was up-regulated by CNP in ROB cells on days 6 and 8, whereas no effect of CNP was observed on days 3 and 12. Brief treatment with 10(-7) M CNP on days 3 through 9 exclusively enhanced the deposition of calcium, a result that suggests that CNP might regulate the expression of mineralization-related genes and, probably, the gene for BGN during a specific time period.

Animals↗
PubMed1999

Ipriflavone down-regulates endothelin receptor levels during differentiation of rat calvarial osteoblast-like cells.

Ipriflavone (7-isopropoxy-3-phenyl-4H-1-benzopyran-4-one) is a synthetic flavonoid that has been shown to stimulate the activity of osteoblasts. We show here that ipriflavone also promotes the deposition of calcium and the formation of mineralized nodules by newborn rat calvarial osteoblast-like (ROB) cells as well as the activity of alkaline phosphatase. We reported previously that endothelin-1 inhibits the differentiation of ROB cells [Y. Hiruma et al. (1998) J. Cardiovasc. Pharmacol. 31, S521-S523]. Therefore, we examined the effects of ipriflavone on the expression of endothelin receptors in ROB cells by polymerase chain reaction-Southern blot analysis and in binding assays with 125I-labeled endothelin-1. Ipriflavone reduced levels of endothelin ETA receptors (to 48% of the control level) in ROB cells around day 7 in our standard cultures, while it had no apparent effect on the expression of the mRNA for the endothelin ETA receptor. By contrast, treatment with 10(-7) M endothelin-1 on days 6 through 9 alone suppressed mineralization by ROB cells. Ipriflavone also reduced the ability of endothelin-1 to inhibit mineralization by ROB cells. These results suggest that the acceleration of osteoblastic differentiation by ipriflavone might be due, at least in part, to a time-specific down-regulation of endothelin receptors.

Animals↗
PubMed1999

Characterization of osteoblastic differentiation of stromal cell line ST2 that is induced by ascorbic acid.

The stromal cell line ST2, derived from mouse bone marrow, differentiated into osteoblast-like cells in response to ascorbic acid. Ascorbic acid induced alkaline phosphatase (ALPase) activity, the expression of mRNAs for proteins that are markers of osteoblastic differentiation, the deposition of calcium, and the formation of mineralized nodules by ST2 cells. We investigated the mechanism whereby ascorbic acid induced the differentiation of ST2 cells. Inhibitors of the formation of collagen triple helices completely blocked the effects of ascorbic acid on ST2 cells, an indication that matrix formation by type I collagen is essential for the induction of osteoblastic differentiation of ST2 cells by ascorbic acid. We furthermore examined the effects of bone morphogenetic proteins (BMPs) on the differentiation of ST2 cells induced by ascorbic acid. Ascorbic acid had no effect on the expression of mRNAs for BMP-4 and the BMP receptors. However, a soluble form of BMP receptor IA inhibited the induction of ALPase activity by ascorbic acid. These results suggest that ascorbic acid might promote the differentiation of ST2 cells into osteoblast-like cells by inducing the formation of a matrix of type I collagen, with subsequent activation of the signaling pathways that involve BMPs.

Alkaline Phosphatase↗
PubMed1999

A possible mechanism of primary ciliary dyskinesia: a case of a segmental defect in ciliary microtubules.

We report here a 13-year-old woman with cough, sputum and fever. The patient had both chronic sinusitis and bronchitis. Chest X-ray and computed tomographic scan of the chest revealed mucous bronchial filling and bronchiectasia in bronchi of bilateral lower lobes, right middle lobe and left upper lobe. Aerosol inhalation scintigraphy with 99mTechnetium demonstrated delays of the discharged tracer. On the basis of these findings, primary ciliary dyskinesia was suggested. This was confirmed by the findings from nasal biopsy with transmission electron microscopy where all of the microtubules were segmentally defected near the basal body in the cilia. On the basis of these findings, we diagnosed the patient with primary ciliary dyskinesia which may be due, at least in part, to segmental defect of ciliary microtubules.

Adolescent↗
PubMed1999

[Treatment of an iliac artery pseudoaneurysm managed with a stent graft].

Recent developments have extended the indications for endovascular intervention to include endovascular lesions, such as aneurysms and sclerotic arterioocclusive disease. Although conventional treatment of pseudoaneurysms is mainly surgical intervention, the development of stent grafts has made this treatment less invasive than previously. We placed a stent graft in a pseudoaneurysm of the iliac artery with good results, as described in this report. Treatment of a pseudoaneurysm with a stent graft avoids the risk associated with general anesthesia and reduces surgical invasiveness, similar to laparotomy. We expect that this therapeutic mode will be developed further in the future.

Aneurysm, False↗