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T Atsumi

Publications and source records attributed to T Atsumi.

At least 127 records · Page 7Linked to original sources
PubMed1997

Cellular hypertrophy and calcification of embryonal carcinoma-derived chondrogenic cell line ATDC5 in vitro.

During the process of endochondral bone formation, proliferating chondrocytes give rise to hypertrophic cells, which then deposit a mineralized matrix to form calcified cartilage prior to replacement by bone. Previously, we reported that a clonal cell line, ATDC5, undergoes efficient chondrogenic differentiation through a cellular condensation stage. Here we report that the differentiated ATDC5 cells became hypertrophic at the center of cartilage nodules, when the cells ceased to grow. Formation of hypertrophic chondrocytes took place in association with type X collagen gene expression and a dramatic elevation of alkaline phosphate (ALPase) activity. After 5 weeks of culture, mineralization of the culture could be discerned as Alizarin red-positive spots, which spread throughout the nodules even in the absence of beta-glycerophosphate. Electron microscopy and electron probe microanalysis revealed that calcification was first initiated at matrix vesicles in the territorial matrix and that it advanced progressively along the collagen fibers in a manner similar to that which occurs in vivo. The infrared spectrum of the mineralized nodules indicated two absorption doublets around 1030 cm-1 and 600 cm-1, which are characteristic of apatitic mineral. Calcifying cultures of ATDC5 cells retained responsiveness to parathyroid hormone (PTH): PTH markedly inhibited elevation of ALPase activity and calcification in the culture in a dose-dependent manner. Thus, we demonstrated that ATDC5 cells keep track of the multistep differentiation process encompassing the stages from mesenchymal condensation to calcification in vitro. ATDC5 cells provide an excellent model to study the molecular mechanism underlying regulation of cartilage differentiation during endochondral bone formation.

Alkaline Phosphatase↗
PubMed1997

Modified Sugioka's osteotomy: more than 130 degrees posterior rotation for osteonecrosis of the femoral head with large lesion.

High degree posterior rotational osteotomy was performed on 31 hips with extensive osteonecrosis that were outside of Sugioka's indication. Among them, 18 hips of 13 patients were reviewed at 24 to 94 months (mean, 42 months). The remaining 13 hips were excluded because the followup was less than 2 years. All hips had less than 1/3 of the posterior area intact preoperatively, which is out of the indication for traditional anterior rotational osteotomy. The posterior rotation applied to the femoral head was 130 degrees to 180 degrees (mean, 138 degrees ). Furthermore, 10 degrees to 25 degrees of intentional varus position was added to the rotation (mean, 15.8 degrees). The preoperative intact articular surface of the loaded portion of the femoral head was 0% to 40% (mean, 6.9%) on anteroposterior radiograph, and it was extended postoperatively to a mean of 80.3% (range, 53%-100%). Collapse was prevented in 17 hips that have remained pain free. The remaining 1 hip sustained secondary collapse and joint narrowing. Mean flexion was 105 degrees and abduction was 20 degrees. Postoperative angiography of 9 hips and bony scintigraphy of 17 hips indicated no findings implying impairment of blood supply. Despite a relatively short term experience, it is concluded that this technique was effective in the treatment of large necrotic lesions, especially for young patients.

Adolescent↗
PubMed1997

[A study of MRI and clinical neurology in acute cerebellar infarcts].

We studied clinical manifestations of sixteen patients with cerebellar infarcts diagnosed by MRI. In fourteen of them, the stroke developed abruptly with vertigo, which continued for several days. At the early stage of illness, ataxia was obscure. But after vertigo and nausea disappeared, nine cases showed truncal ataxia, while limb ataxia was found in only five. Their vertigo was rotatory and aggravated by head movement. Gaze-evoked nystagmus was observed in only 5 cases. Four patients preferred to take unilateral posture since they experienced less vertigo. The side of their lesions was the lower side of their posture. Limb ataxia was more frequent in SCA-involving cases than in SCA-non involving cases (3 out of 6 vs 2 out of 10, respectively). On the other hand, headache was more frequent in PICA-involving cases than in PICA-non-involving cases (6 out of 11 vs 1 out of 5, respectively). Ataxic gait was seen more in medial branch-involving cases than medial branch non-involving cases (5 out of 6 vs 4 out of 10, respectively). One patient died due to obstructive hydrocephalus.

Adult↗
PubMed1996

Simultaneous measurement of Ca2+ and pH by laser cytometry using fluo-3 and SNARF-1.

We present a new convenient method for simultaneous measurement of intracellular calcium concentration ([Ca2+]i) and intracellular pH (pHi) using laser cytometry with a mixture of fluo-3 (for [Ca2+]i) and SNARF-1 (for pHi), with iso excitation (488 nm)-dual emission (530 nm for fluo-3 and > 630 nm for SNARF-1). By using this technique, we measured the changes in [Ca2+]i and pHi in A-431 human epidermoid carcinoma cells and HSG human salivary gland cells stimulated by ATP. We found that alkalization in A-431 cell occurred with the elevation of [Ca2+]i; in contrast, alkalization in HSG cells did not occur at all, even though the elevation of [Ca2+]i was observed. Using BAPTA (a chelating agent of Ca2+) and amiloride (an inhibitor of the Na+/H+ exchanger), we found that the elevation of pHi requires the elevation of [Ca2+]i but that the elevation of [Ca2+]i does not always require a rise in pHi. From our results we conclude that elevation of [Ca2+]i takes precedence over the elevation of pHi in ATP-stimulated signal transduction.

Adenosine Triphosphate↗
PubMed1996

Chondrogenic differentiation of clonal mouse embryonic cell line ATDC5 in vitro: differentiation-dependent gene expression of parathyroid hormone (PTH)/PTH-related peptide receptor.

The regulatory role of parathyroid hormone (PTH)/PTH-related peptide (PTHrP) signaling has been implicated in embryonic skeletal development. Here, we studied chondrogenic differentiation of the mouse embryonal carcinoma-derived clonal cell line ATDC5 as a model of chondrogenesis in the early stages of endochondral bone development. ATDC5 cells retain the properties of chondroprogenitor cells, and rapidly proliferate in the presence of 5% FBS. Insulin (10 micrograms/ml) induced chondrogenic differentiation of the cells in a postconfluent phase through a cellular condensation process, resulting in the formation of cartilage nodules, as evidenced by expression of type II collagen and aggrecan genes. We found that differentiated cultures of ATDC5 cells abundantly expressed the high affinity receptor for PTH (Mr approximately 80 kD; Kd = 3.9 nM; 3.2 x 10(5) sites/cell). The receptors on differentiated cells were functionally active, as evidenced by a PTH-dependent activation of adenylate cyclase. Specific binding of PTH to cells markedly increased with the formation of cartilage nodules, while undifferentiated cells failed to show specific binding of PTH. Northern blot analysis indicated that expression of the PTH/PTHrP receptor gene became detectable at the early stage of chondrogenesis of ATDC5 cells, preceding induction of aggrecan gene expression. Expression of the PTH/PTHrP receptor gene was undetectable in undifferentiated cells. The level of PTH/PTHrP receptor mRNA was markedly elevated parallel to that of type II collagen mRNA. These lines of evidence suggest that the expression of functional PTH/PTHrP receptor is associated with the onset of chondrogenesis. In addition, activation of the receptor by exogenous PTH or PTHrP significantly interfered with cellular condensation and the subsequent formation of cartilage nodules, suggesting a novel site of PTHrP action.

Adenylyl Cyclases↗
PubMed1996

Specificity of ELISA for antibody to beta 2-glycoprotein I in patients with antiphospholipid syndrome.

The clinical significance of anti-beta 2 glycoprotein I (beta 2-GPI) antibodies was evaluated in patients with antiphospholipid syndrome (APS), primary and secondary to systemic lupus erythematosus (SLE). Anti-beta 2-GPI were tested in 120 patients (39 primary APS, 32 APS with SLE and 49 SLE without APS) by ELISA utilizing irradiated plates in the absence of cardiolipin. Anticardiolipin antibodies (aCL) and antiphosphatidylserine antibodies were also measured in the same patients using standardized assays. Anti-beta 2-GPI titres correlated strongly to those of aCL (r = 0.816, P = 0.0001), and to those of antiphosphatidylserine antibodies (r = 0.841, P = 0.0001). Anti-beta 2-GPI were detected in 53.5% of APS patients (38/71), but only in 4.1% of SLE patients without APS (2/49). In the latter group, 24.5% (12/49) of patients had a positive titre of aCL. The anti-beta 2-GPI assay showed higher specificity for APS than the aCL in APS (96 vs 75%, respectively, chi 2 = 6.75, P = 0.00094). Our findings suggest that the assay of anti-beta 2-GPI may improve the specificity for APS.

Adult↗
PubMed1996

Revascularization in nontraumatic osteonecrosis of the femoral head.

To study the revascularization pattern of nontraumatic osteonecrosis, superselective angiography of the femoral medical circumflex artery was done twice on 13 hips for which no treatment had been given. Angiographic evaluation of the hips with early-stage osteonecrosis not visible on radiographs showed the absence of superior retinacular arteries from the stump in all hips. Penetration of small vessels was seen on 6 hips. Bony scintigraphy of 13 hips and magnetic resonance imaging of 9 hips were taken at about the same time. Bony scintigraphy and magnetic resonance imaging results were positive in 11 of 13 hips and in all 9 hips, respectively. The patients were observed until evidence of necrosis appeared on radiographs. When this sign became evident, a second angiography was conducted, which indicated the penetration of erratically formed vessels with increase in size in 12 hips. It was assumed that the blood supply from the superior retinacular arteries was interfered with in large areas of the femoral head and that revascularization started with the formation of small vessels, followed by further penetration of large vessels.

Adolescent↗
PubMed1996

Effect of viscosity on swimming by the lateral and polar flagella of Vibrio alginolyticus.

By using mutants of Vibrio alginolyticus with only a polar flagellum (Pof+ Laf-) or only lateral flagella (Pof- Laf+), we examined the relationship between swimming speed and the viscosity of the medium for each flagellar system. Pof+ Laf- cells could not swim in the high-viscosity environment (ca. 200 cP) in which Pof- Laf+ cells swam at 20 microns/s. The Pof- Laf+ cells swam at about 20 microns/s at normal viscosity (1 cP) without the viscous agent, and the speed increased to 40 microns/s at about 5 cP and then decreased gradually as the viscosity was increased further. These results show the functional difference between polar and lateral flagella in viscous environments.

Cell Movement↗
PubMed1996

ATP- and EGF-stimulated phosphatidulinositol synthesis by two different pathways, phospholipase D and diacylglycerol kinase, in A-431 epidermoid carcinoma cells.

The [(3)H]inositol incorporation into the membrane fraction of A-431 human epidermoid carcinoma cells was markedly increased by stimulation of the cells with either epidermal growth factor (EGF), ATP, bradykinin, or a calcium ionophore A23187 in the presence of 1 mM extracellular calcium ions; most incorporated [(3)H]inositol was found to have accumulated as phosphatidylinositol (PI). The EGF- and ATP-stimulated PI synthesis was inhibited by two protein kinase C inhibitors, staurosporine and 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7), and an intracellular calcium chelator, 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester (BAPTA/AM), but not by the calmodulin antagonist N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7). Pretreatment of cells with pertussis toxin (IAP, islet-activating protein) inhibited the PI synthesis, [Ca(2+)]i elevation, and inositol trisphosphate (IP(3)) production by ATP, suggesting that the phospholipase C(PLC) system coupled with IAP-sensitive G protein is involved in the ATP-stimulated PI synthesis. On the other hand, the ATP stimulation increased the release of [(3)H]choline and [(32)P)phosphatidic acid (PA) from radiolabeled cells, and such release was not inhibited by IAP. In the presence of n-butyl alcohol, which prevents the production of PA by generation of phosphatidylbutanol, the ATP-stimulated PI synthesis was reduced. Because n-butyl alcohol did not inhibit IP(3) production and [Ca(2+)]i elevation, this fact suggests that the lAP-insensitive PLD system is involved in the ATP-stimulated PI synthesis. In A-431 cells, the stimulation of P(2)-purinergic receptors appears to activate the IAP-sensitive PLC system and IAP-insensitive PLD system, both of which are essential for the stimulation of PI synthesis. The present results imply the general prospect that ligand stimulation, which mobilizes second messengers and consumes their precursors, simultaneously provokes the pathway to synthesize and salvage the second messenger precursors as well.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1996

Isolation of a germline-transmissible embryonic stem (ES) cell line from C3H/He mice.

We have isolated three embryonic stem (ES) cell lines from C3H/He mice using mouse STO cells as a feeder layer. One ES cell line (H-1) was male, and two (H-2 and H-3) were female, as determined by polymerase chain reaction, in situ hybridization, and karyotype analyses. All were immunocytochemically reactive with a C3H strain-specific antibody. Injection of cells from the female ES H-3 line into C57BL/6 blastocysts yielded four chimeras with slight coat color chimerism. All chimeras were male, and as expected, no germline-transmission was observed. By contrast, when male ES H-1 cells were injected into the perivitelline space of 8-cell C57BL/6 embryos, one male mouse with overt coat color chimerism was recovered, and it produced ES H-1-derived offspring exclusively. This germline-transmissible C3H/He cell line represents a novel addition to those ES lines currently employed for gene manipulation studies of development.

Animals↗
PubMed1996

[A case with perineuritis].

We reported a 62-year-old woman with perineuritis. She suffered from dysesthesia in the right radial wrist. One month later, dysesthesia in the left radial wrist occurred. Four months later, dysesthesia developed in both soles of the foot. On a neurologic examination, hypalgesia, hypesthesia, dysesthesia and areflexia were disclosed. Sensory disturbance was a distal dominant distribution. Serum anti-Borrelia burgdorferi antibody was not detected. Cerebrospinal fluid examination revealed normal protein content and cell numbers. Motor nerve conduction velocities were normal, but the sensory nerve conduction velocity of median nerve, ulnar nerve and sural nerve could not be elicited. Sural nerve biopsy revealed marked thickening of perineurium and infiltration of mononuclear cells in and around the perineurium. The infiltration of mononuclear cells was also observed around middle-sized epineurial artery and arterioles. Treatment with daily 40 mg of prednisolone only relieved the dysesthsia. After treatment with daily 60 mg of prednisolone the sensory disturbance was gradually improved. Sensory nerve potential could be evolved seven months later.

Anti-Inflammatory Agents↗
PubMed1996

[Familial amyloidotic polyneuropathy with a transthyretin variant (Val30-->Leu)].

We report a Japanese woman with familial amyloidotic polyneuropathy (FAP) with a transthyretin variant that substituted leucine for valine at position 30. Family history was not informative. She had initially suffered from repeated petechiae in the eyelids at the age of 51. Two years later, dysesthesia in the lower extremities appeared. Distal muscle weakness and sensory disturbance gradually developed. Autonomic dysfunction emerged and vomiting and orthostatic hypotension were marked in the late stage of her illness. Because of renal failure, she died at the age of 54. At autopsy, amyloid deposits were prominent in peripheral nerves including autonomic nerves, heart, blood vessels, gastrointestinal tract, kidneys, and bladder. In the nervous system, we found amyloid deposits in anterior roots, posterior roots, posterior root ganglions, peripheral nerves, and sympathetic ganglions. Cardiac weight was increased (595 g) with conspicuous amyloid deposits in the myocardium. The kidneys showed massive deposition of amyloid in the glomeruli and vascular walls. Amyloid accumulated moderately in tongue, submandibular gland, gallbladder, spleen, and pancreas, and slightly in the thyroid gland, lung, liver, and adrenal gland. No amyloid deposits were seen in the CNS with the exception of perivascular deposits in the choroid plexus.

Amyloid↗
PubMed1996

Clinical significance of anti-beta 2-glycoprotein I antibodies.

Antiphospholipid antibodies are a heterogeneous group of autoantibodies with clinical importance because of their strong association with thrombotic events. Recent evidence have shown that antiphospholipid antibodies are not directed against phospholipids, as has previously been thought, but are a part of a large family of autoantibodies against phospholipid-binding plasma proteins. So far, one of the most common and best characterized antigenic target is beta 2-glycoprotein I (beta 2-GPI), which plays an important role in the binding of anticardiolipin antibodies (aCLA) to cardiolipin. The detection of anti-beta 2-GPI antibodies by using a simple and rapid ELISA may facilitate the recognition of alpha "pathogenic" alpha aCL in antiphospholipid syndrome.

Antibodies, Anticardiolipin↗
PubMed1996

[A case of an old woman with Sjögren's syndrome associated with insulin-dependent diabetes mellitus].

Insulin-dependent diabetes mellitus (IDDM) is thought to result from the autoimmune destruction of the insulin-dependent beta cells of the pancreas. Sjögren's syndrome is also an autoimmune disease characterized by the destruction of the lacrimal and salivary glands that leads to keratoconjunctivitis sicca and xerostomia. But it is a very rare case that a patient with Sjögren's syndrome developed IDDM. We present a case of a 65-year old woman with Sjögren's syndrome who developed diabetic ketoacidosis due to IDDM. Recent studies have revealed that there was molecular mimicry between glutamic acid decarboxylase (GAD) and coxsackievirus. Furthermore, some reports have shown that sialadenitis was represented in IDDM model mice. This case shows the possibility that a causal relationship between IDDM and Sjögren's syndrome may exist.

Aged↗
PubMed1995

Focal adhesion kinase is not essential for in vitro and in vivo differentiation of ES cells.

Focal adhesion kinase, FAK, is a unique protein tyrosine kinase found in cellular focal adhesions. It is widely expressed and highly phosphorylated during embryogenesis. To examine the function of FAK in cell differentiation, we made FAK-deficient embryonic stem (ES) cells by homologous recombination. However, FAK-deficiency did not interfere with differentiation of the ES cells into cells of three germ layers when implanted subcutaneously into nude mice or when treated with retinoic acid in vitro, nor was there any evidence of defects in hematopoiesis in vitro.

Animals↗
PubMed1995

Detection of hydrogen peroxide and hydroxyl radicals in murine skin fibroblasts under UVB irradiation.

The purpose of this study was to identify the active oxygen species generated in murine skin fibroblasts under UVB irradiation. When fibroblasts were exposed to UV light (UVA + UVB), hydroxyl radicals were detectable by ESR-spin trapping using DMPO as a spin trapping agent. Cell damage induced by UVB irradiation was prevented by addition of DMSO, a typical hydroxyl radical scavenger. Fibroblasts treated with a catalase inhibitor 3-amino-1H-1,2,4-triazole were more sensitive to UVB irradiation than untreated-cells, but the sensitivity was improved by addition of DMSO. To find the origin of the hydroxyl radicals in fibroblasts during UVB irradiation, H2O2 was determined by dihydrorhodamine 123 and it was found that the formation of H2O2 increased under UVB irradiation. These results suggest that UVB-irradiated skin fibroblasts produce H2O2 and were followed by the formation of hydroxyl radicals, probably derived from the Fenton-like reaction (H2O2 + Fe2+ --> .OH + OH- + Fe3+), which in turn damages the cells.

Animals↗