Biomedical subjects

K Tezuka

Publications and source records attributed to K Tezuka.

At least 37 records · Page 2Linked to original sources

PubMed1998

Interleukin-1beta induces tissue- and cell type-specific expression of adhesion molecules in vivo.

We examined the tissue distribution of adhesion molecule gene expression in mice treated intravenously with interleukin (IL)-1 beta. E-selectin mRNA expression was selectively induced in the heart by IL-1 beta, but only slight or no induction was observed in other organs. On the other hand, intercellular adhesion molecule-1 mRNA expression was inducible in all organs examined, although it showed the strongest induction in the lung and the weakest responses in the brain and skin. Vascular cell adhesion molecule-1 mRNA was also inducible in all organs with the exception of the skin, but it was induced most markedly in the lung and the heart. The accessibility of IL-1 beta to the heart was less than that to other organs except the brain. Similar tissue-specific induction of these mRNAs was also seen when tumor necrosis factor (TNF)-alpha or lipopolysaccharide was substituted for IL-1 beta. Analysis of E-selectin mRNA expression in the heart by in situ hybridization indicated that expression was most prominent in microvascular endothelial cells and some other stromal cells, but this transcript was not seen in the lung. Although intercellular adhesion molecule-1 mRNA expression was restricted to the endothelium lining the capillaries and small arteries in the heart, its distribution in the lung covered not only the endothelium but also the cells composing the alveolar septa. In contrast, vascular cell adhesion molecule-1 mRNA expression was most prominent in endothelial cells of larger vessels in both the heart and the lung. Our results demonstrate that expression of adhesion molecules is tissue- and cell type-specific and that endothelial cells differentially express adhesion molecules depending on the size of the blood vessels.

Animals↗

PubMed1996

Safe and effective topical application dose of lidocaine for surgery with laryngomicroscopy.

A clinical case of a patient in whom seizure developed after topical application of lidocaine to the oropharyngeal region was described. The exploratory studies on the optimal dosage of lidocaine in the surgery under laryngomicroscope was performed in 22 patients. During the application of 2% lidocaine viscous and 4% lidocaine solution to the oropharyngeal region, the patient was instructed to expectorate the excess intermittently to avoid absorption. In addition, the oropharyngeal region was swabbed with gauze. The serum lidocaine concentrations after application were less than 1.8 micrograms/ml. The total application dose of the drug was within the range of 324 to 640 mg, and the total recovery rate from the saliva and gauze was 52% to 81%. We found a good correlation between net application dose (total application dose minus excessive lidocaine dose) and serum lidocaine concentration. In this study, it was shown that the safe and effective net application dose of lidocaine for the surgery may be within the range of 127 to 260 mg.

Administration, Topical↗

PubMed1995

Retinoic acid directly stimulates osteoclastic bone resorption and gene expression of cathepsin K/OC-2.

Vitamin A metabolites such as all-trans-retinoic acid (all-trans-RA) affect several steps of metabolic processes in vertebrates. In the last few years, several studies have shown the effect of RA on bone formation and metabolism. However, mechanisms of its action still remain unclear, especially with respect to the regulation of bone cells. Therefore, this study was carried out to clarify how RA regulates the activity of osteoclasts. Using a pit assay involving unfractionated bone cells, including osteoclasts obtained from rabbits, we found that RA stimulated an increase in the bone-resorbing activity in a dose- and time-dependent manner. Furthermore, this effect occurred more rapidly than that of treatments with 1 alpha,25-dihydroxyvitamin D3. However, this effect of RA may be partly related to cross-talk between osteoclasts and other types of cells. Therefore we studied the effect of RA on isolated osteoclasts. We found that all-trans-RA regulates the gene expression of cathepsin K/OC-2, a dominant cysteine proteinase, at the transcriptional level in mature osteoclasts isolated from rabbits. Moreover, retinoic acid-receptor alpha mRNA and retinoid X-receptor beta mRNA were expressed in these mature osteoclasts. Our results indicate that osteoclasts are target cells for RA and that RA might regulate a part of bone formation and metabolism through osteoclasts.

Animals↗

PubMed1995

Molecular cloning of human cDNA for cathepsin K: novel cysteine proteinase predominantly expressed in bone.

We have previously cloned a rabbit cDNA clone (OC-2) from an osteoclast cDNA library by the differential screening. OC-2 was found to encode a novel cysteine proteinase, tentatively called cathepsin K, which is predominantly expressed in osteoclasts. By use of a rabbit OC-2 fragment as a probe, its human counterpart was cloned from a cDNA library of osteoarthritic hip bone. The cloned human cDNA (hOC-2) encoded a protein of 329 amino acid residues and its deduced amino acid sequence showed 94% homology to rabbit cathepsin K. Multiple alignment of amino acid sequences of human cathepsins B, H, L, S and K showed the highest homology of cathepsin K to cathepsin S 48%. Northern blot analysis showed that cathepsin K mRNA is expressed at high levels in some osteoarthritic hip bones and at a very high level in osteoclastoma compared to very low levels in other tissues. These results suggest that cathepsin K is closely involved in human osteoclastic bone resorption.

Amino Acid Sequence↗

PubMed1995

Hepatocyte growth factor is involved in formation of osteoclast-like cells mediated by clonal stromal cells (MC3T3-G2/PA6).

Osteoclast formation from hemopoietic precursors has been shown to require the support of stromal cells in bone tissue. In this study, we demonstrated that hepatocyte growth factor (HGF) is one of the stromal cell-derived molecules responsible for osteoclast-like cell formation. For our experiments, we used a coculture system for osteoclastic cell formation and activation in which hemopoietic blast cells are cocultured with calvaria-derived stromal MC3T3-G2/PA6 (PA6) cells on dentine slices in the presence of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. Addition of anti-HGF neutralizing IgG to the cocultures inhibited the formation of osteoclastic cells and their dentine-resorbing activity. We detected a single 6.0-kb transcript for HGF in PA6 cells, and also recognized immunoreactive M(r) 81,000 and 88,000 forms of HGF in conditioned medium (CM) from PA6 cell cultures, the level of which reached 6 ng/ml. Both the CM and HGF stimulated the proliferation of blast cells synergistically with granulocyte-macrophage colony-stimulating factor, resulting in an increased number of osteoclast precursors that respond to 1,25(OH)2D3 that are tartrate-resistant acid phosphatase-positive multinucleate cells in stromal cell-free blast cell cultures in plastic wells. The effect of the CM was diminished by the addition of anti-HGF IgG. However, neither the CM nor HGF stimulated the formation of osteoclastic cells and pits on dentine slices in the absence of PA6 cells. These results suggest that although HGF cannot completely replace stromal cells, it is one of the paracrine mediators produced by stromal cells that act on proliferation of osteoclastic cell precursors.

Acid Phosphatase↗

PubMed1995

Isolation and characterization of highly enriched, prefusion mouse osteoclastic cells.

This study describes the isolation and characterization of highly enriched mammalian osteoclast precursors, released by the "disintegrin" echistatin, from an osteoclast formation culture. Incubation of a 6-day coculture of mouse bone marrow cells and mouse osteoblastic cells (MB1.8) with echistatin (30 nM), an RGD-containing snake venom, for 20 min yielded an 88-95% pure population of tartrate-resistant acid phosphatase-positive cells, 1.5 x 10(5) cells per 150 cm2 culture dish. These cells were mostly mononucleated and based on the following characteristics are considered to be prefusion osteoclasts (pOC cells): (i) presence of calcitonin (CT) receptors documented by 125I-sCT autoradiography and cAMP generation in response to salmon calcitonin; (ii) expression of mRNAs for alpha v beta 3 integrin, osteopontin, 92-kDa type IV collagenase (matrix metalloproteinase 9), carbonic anhydrase II, OC-2 (an "osteoclastic" cysteine proteinase), and protein tyrosine phosphatase epsilon; and (iii) high level expression of pp60c-src protein. The pOC cells resorb bone (form "pits" on bone slices) but only in the presence of osteoblastic MB1.8 cells and 1,25(OH)2D3. Resorption was inhibited by CT. In conclusion, we describe a rapid, reproducible procedure to isolate virtually pure mammalian prefusion osteoclasts, which should help in the study of osteoclast formation, composition, and function.

Animals↗

PubMed1995

Entire scalp replantation: case report and review of the literature.

A case of successful replantation of a totally avulsed scalp in a 40-year-old woman is presented. During a 19-hr surgical procedure, bilateral superficial temporal arteries and veins were anastomosed. The postoperative course was uneventful, except for partial necrosis of the distal end of the avulsed flap, i.e., the occipital region. Since the first successful scalp replantation using microsurgical technique was reported in 1976, the authors have found at least 32 subsequently reported cases. Of these, there were 22 cases of entire scalp avulsion (more than 80 percent of the scalp), including 15 females and seven males. A summary of these cases is included. From analysis of the reported cases of entire scalp avulsion, the keys to success in scalp replantation are considered to be the adequate selection of vessels for repair and the use of vein grafts, if necessary.

Adult↗

PubMed1995

Recognition of consensus CHO structure in ligands for selectins by novel antibody against sialyl Lewis X.

The selectins (L, E, and P) play an important role in the earliest events of the inflammatory response, leading to the "rolling" phenomenon. All selectins react with sialyl Lewis X (SLex) in vitro, possibly suggesting that their ligands have a consensus structure. 2H5 is a monoclonal antibody against SLex that blocks L-selectin-mediated adhesion. 2H5 inhibited adhesion of HL-60 cells to P- and E-selectin-producing COS cells in vitro and immunoprecipitated a P-selectin glycoprotein ligand-1-like glycoprotein from HL-60 cell lysate, suggesting that it recognizes a functional consensus structure on the ligands for all selectins. 2H5 reacted not only with human but also with rat and mouse neutrophils. 2H5 is the first antibody against SLex that recognizes neutrophils of nonhuman mammals. The carbohydrate structure recognized by 2H5 was present not only on high endothelial venules of rat lymphoid organs but also on the endothelial cells of nonlymphoid organs. Furthermore, administration of the antibody markedly inhibited L- and P-selectin-mediated neutrophil rolling and adhesion in rat mesenteric venules in vivo. These results provide evidence for the presence of a consensus carbohydrate structure on the ligands for all selectins. The consensus structure thus has the potential to serve as a therapeutic target.

Animals↗

PubMed1995

Time-lapse microcinematography of osteocytes.

We succeeded in the isolation of osteocytes from parietal bones of 16-day-old chick embryos. Isolated osteocytes showed a typical stellate morphology. More than 95% of these cells reacted with the osteocyte-specific antibody OB 7.3. In culture osteocytes formed gap junctions with each other, as could be established by ACAS. Sixteen-millimeter time-lapse microcinematography of the cells also demonstrated the formation of intercellular connections and gap junctions, and portrayed the interaction between osteocytes and osteoclasts: osteocytes seemed to inhibit osteoclast activity. This cinematography also showed the ability of osteocytes to proliferate after they had been disconnected from each other. Thereafter these cells redifferentiated into osteoblasts that became embedded in bone matrix produced by themselves. These findings suggest that osteocytes might be involved in bone formation during remodeling.

Animals↗

PubMed1994

Selective inhibition of lignoceroyl-CoA synthetase by adenosine 5'-alkylphosphates.

Structural analogs of adenosine 5'-acylphosphates, which are intermediates of the reaction catalyzed by acyl-CoA synthetases, were synthesized by condensing primary alcohols with AMP to examine the inhibitory effects on the lignoceroyl-CoA and palmitoyl-CoA synthetase activities. Hexadecyl, octadecyl, eicosyl, docosyl and tetracosyl esters of AMP were remarkably potent inhibitors of the lignoceroyl-CoA formation. On the other hand, the eicosyl, docosyl or tetracosyl esters of AMP did not behave as significant inhibitors of the palmitoyl-CoA formation at the concentration at which the two other shorter chain analogs were effective. Namely, these longer alkyl esters of AMP have selective inhibitory effects on the lignoceroyl-CoA synthetase activity. The Ki value of adenosine 5'-tetracosylphosphate, the most potent inhibitor, was about one tenth lower than the Km value for the substrate lignoceric acid. Furthermore, the results support the notion that lignoceroyl-CoA synthetase is distinct from palmitoyl-CoA synthetase.

Adenosine Monophosphate↗

PubMed1994

Identification of matrix metalloproteinase 9 in rabbit osteoclasts.

Osteoclasts are multinucleate giant cells that play key roles in bone resorption. To identify genes predominantly expressed in osteoclasts, we screened a cDNA library of osteoclasts with cDNA probes of osteoclasts and alveolar macrophages. Clones specifically hybridizing to the osteoclast probe were isolated and sequenced. The nucleotide sequence of one such clone, F17, was found to share significant similarity with the sequences of human and mouse matrix metalloproteinase 9 (MMP-9) cDNA. By isolation and sequencing of the full-length cDNA, F17 was revealed to encode the rabbit counterpart of MMP-9. By Northern blotting, messenger RNA for MMP-9 was found to be highly and predominantly expressed in isolated osteoclasts when compared with its level in alveolar macrophages and other tissues. By gelatin zymography, gelatinase activity was detected in conditioned medium of isolated osteoclasts, suggesting that MMP-9 is secreted by isolated osteoclasts. Expression of MMP-9 was also observed in in vivo osteoclasts in metacarpal bones of newborn rabbits by in situ hybridization. These facts suggest that MMP-9 is one of the major proteases produced by osteoclasts and possibly plays a role in osteoclastic bone resorption.

Amino Acid Sequence↗

PubMed1994

Molecular cloning of a possible cysteine proteinase predominantly expressed in osteoclasts.

Osteoclasts are multinucleate giant cells playing key roles in bone resorption. These cells solubilize mineralized bone matrix by means of acid and protease action; however, the precise mechanism of this process is not well known. Recently, we succeeded in the isolation of pure osteoclasts from rabbit bones and constructed a cDNA library. Using a differential screening procedure, two genes expressed predominantly in osteoclasts compared with spleen cells were isolated (Tezuka, K., Sato, T., Kamioka, H., Nijweide, P. J., Tanaka, K., Matsuo, T., Ohta, M., Kurihara, N., Hakeda, Y., and Kumegawa, M. (1992) Biochem. Biophys. Res. Commun. 186, 911-917). One of them, OC-2, was found to encode a possible cysteine proteinase structurally related to cathepsins L and S. By in situ hybridization, OC-2 was confirmed to be expressed in osteoclasts in vivo. By Northern blot analysis, OC-2 was highly and preferentially expressed in osteoclasts compared with other tissues such as kidney, liver, spleen, and lung. The predominant expression of OC-2 in osteoclasts may suggest that OC-2 encodes a protein, possibly a cysteine proteinase, that plays an important role in osteoclastic bone resorption.

Amino Acid Sequence↗

PubMed1994

Stimulatory effect of a phorbol ester on expression of insulin-like growth factor (IGF) binding protein-2 and level of IGF-I receptors in mouse osteoblastic MC3T3-E1 cells.

We examined the relationship between signal transduction and the expression of insulin-like growth factor I (IGF-I), IGF-I receptor level, and IGF binding proteins (IGFBPs) in murine clonal osteoblastic MC3T3-E1 cells. 12-O-Tetradecanoylphorbol-13-acetate (TPA), an activator of protein kinase C, decreased the secretion of immunoreactive IGF-I into the medium, whereas dibutyryl cAMP (Bt2cAMP) augmented the secretion. In contrast, TPA increased the level of type I IGF receptor on the cells. Furthermore, MC3T3-E1 cells produced and secreted at least three different IGFBPs with molecular masses of 24, 30, and 34 kDa, and the 24-kDa IGFBP was predominant under normal conditions. However, TPA specifically increased the secretion of the 34-kDa IGFBP. The N-terminal amino acid sequence of the purified 34-kDa IGFBP was nearly identical with that of rat IGFBP-2. Furthermore, the 34-kDa IGFBP was immunoreactive to anti-IGFBP-2 antiserum. The level of IGFBP-2 mRNA in the cells was increased by TPA, indicating that the increase in IGFBP-2 secretion results from the stimulation of IGFBP-2 production. In contrast, Bt2cAMP affected neither IGF-I receptor number nor the IGFBP secretion. These results indicate that the production of IGF-I and the expression of IGF-I receptors and IGFBP-2 are up-regulated by the activation of adenylate cyclase and protein kinase C, respectively, in osteoblastic MC3T3-E1 cells.

Adenylyl Cyclases↗

PubMed1994

Calcitonin inhibits osteopontin mRNA expression in isolated rabbit osteoclasts.

Recent evidence indicates that osteopontin (Opn), one of the bone matrix proteins, plays an important role in the attachment of osteoclasts to bone matrix. Besides being elaborated by osteoblasts, this protein is also produced by osteoclasts. The present study was performed to examine the effect of calcitonin (CT) on Opn mRNA expression of isolated rabbit osteoclasts and to clarify the second messenger signaling of this effect. Eel CT inhibited Opn mRNA expression as well as bone-resorbing activity of isolated rabbit osteoclasts. Eel CT caused a transient increase in intracellular calcium followed by a sustained increase as well as an increase in cAMP production in these cells. Dibutyryl-cAMP (10(-4) M) and Sp-cAMPS (10(-4) M), an activator of cAMP-dependent protein kinase (PKA), as well as A23187 (10(-7) M), a calcium ionophore, and phorbol myristate acetate (10(-7) M), an activator of protein kinase C (PKC), caused a significant inhibition of Opn mRNA expression, and suppressed bone-resorbing activity of isolated osteoclasts. The present study is the first to demonstrate that CT inhibits Opn mRNA expression in isolated rabbit osteoclasts, presumably through the activation of PKA and calcium/PKC pathways, by which the bone-resorbing activity might be attenuated subsequently.

Animals↗

PubMed1993

Osteoblast-specific factor 2: cloning of a putative bone adhesion protein with homology with the insect protein fasciclin I.

A cDNA library prepared from the mouse osteoblastic cell line MC3T3-E1 was screened for the presence of specifically expressed genes by employing a combined subtraction hybridization/differential screening approach. A cDNA was identified and sequenced which encodes a protein designated osteoblast-specific factor 2 (OSF-2) comprising 811 amino acids. OSF-2 has a typical signal sequence, followed by a cysteine-rich domain, a fourfold repeated domain and a C-terminal domain. The protein lacks a typical transmembrane region. The fourfold repeated domain of OSF-2 shows homology with the insect protein fasciclin I. RNA analyses revealed that OSF-2 is expressed in bone and to a lesser extent in lung, but not in other tissues. Mouse OSF-2 cDNA was subsequently used as a probe to clone the human counterpart. Mouse and human OSF-2 show a high amino acid sequence conservation except for the signal sequence and two regions in the C-terminal domain in which 'in-frame' insertions or deletions are observed, implying alternative splicing events. On the basis of the amino acid sequence homology with fasciclin I, we suggest that OSF-2 functions as a homophilic adhesion molecule in bone formation.

3T3 Cells↗

PubMed1993

cDNA expression cloning of the 85-kDa protein overexpressed in adriamycin-resistant cells.

An 85-kDa cell surface protein recognized by monoclonal antibody MRK-20 was identified in adriamycin-resistant tumor cells. The expression of the 85-kDa protein has recently been reported to be associated with the differentiation of hematopoietic cells. However, the primary structure of the 85-kDa protein has not been determined. To clarify its primary structure, we carried out cDNA expression cloning of the 85-kDa protein with monoclonal antibody MRK-20. We found that the 85-kDa protein is identical to CD36 (GP VI), but at least two species of transcript exist in the tumor cells and one of these transcripts has a novel sequence at the 3'-region. The transcript with the novel sequence at the 3'-region was found to be expressed during the differentiation of hematopoietic cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1993

Purification and substrate specificity of beta-xylosidase from sycamore cell (Acer pseudoplatanus L.): application for structural analysis of xylose-containing N-linked oligosaccharides.

A beta-xylosidase was purified 51-fold from culture medium of sycamore (Acer pseudoplatanus L.) cells using p-nitrophenyl beta-D-xylopyranoside as a substrate. This enzyme can remove a xylose residue from asparagine-linked oligosaccharides, derivatized with 2-aminopyridine. A pentasaccharide, Xy1 beta 2Man beta 4GlcNAc beta 4(Fuc-alpha 3)GlcNAc was the favorite substrate in N-linked oligosaccharides, but a xylose residue in Xy1 beta 2(Man-alpha 3)Man beta sequence could not be removed by the enzyme. We also propose an efficient method for detection of xylose residue in N-linked oligosaccharides by a combination of the two-dimensional sugar mapping technique and the xylosidase digestion.

Carbohydrate Sequence↗

PubMed1993

Occurrence of heterogeneity of N-linked oligosaccharides attached to sycamore (Acer pseudoplatanus L.) laccase after excretion.

The N-linked oligosaccharide moieties of sycamore (Acer pseudoplatanus L.) laccase are known to be highly heterogeneous. We confirmed that this oligosaccharide heterogeneity was caused not only during the oligosaccharide biosynthesis in Golgi apparatus, but also after the excretion of laccase protein into a culture medium. The culture medium for the sycamore cells (Acer pseudoplatanus L.) contained beta-galactosidase, alpha-L-fucosidase, beta-N-acetylglucosaminidase, alpha-mannosidase and beta-xylosidase activities. We showed that the largest sugar chain in laccase, oligosaccharide F, [formula: see text] was degraded to [formula: see text] by a crude exoglycosidase mixture in the culture medium.

Acetylglucosaminidase↗