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I Nishimura

Publications and source records attributed to I Nishimura.

At least 73 records · Page 4Linked to original sources
PubMed1992

Site-specific expression of collagen I and XII mRNAs in the rat periodontal ligament at two developmental stages.

In mammals, the periodontal ligament (PDL) is a highly specialized tissue which facilitates tooth eruption and lends mechanical support to the tooth once in occlusion. The PDL extracellular matrix fibers play a major role in such functions. During its development, the spatial arrangement of the PDL extracellular matrix undergoes rapid changes. So that it could be determined whether the structural alteration in the PDL is associated with changes in the expression of collagenous proteins with different functional properties, the transcriptional patterns of collagens I and XII were examined. The maxillary dento-alveolar segments, each containing three molars, from 25-day-old and 40-day-old Sprague-Dawley rats were selected as being representative of developing and matured tissues, respectively. Rat alpha 2(I) collagen cDNA and rat alpha 1(XII) collagen cDNA were used as molecular probes for identification of the corresponding mRNAs by RNA transfer blot analysis, RNase protection assay, and in situ hybridization. The results showed that alpha 2(I) collagen mRNA was expressed in both developing and matured tissues. However, the level of expression decreased with maturity. In contrast, the expression of alpha 1(XII) collagen was increased in the matured tissue as compared with the developing tissue. In situ hybridization in these tissues indicated that the expression of alpha 1(XII) collagen mRNA was limited to the mature stage of PDL development. It is suggested that collagen fibril arrangement during PDL development may be related to the expression of collagen XII.

Aging↗
PubMed1991

Molecular cloning of the complementary DNA encoding for the hamster TGF-alpha mature peptide.

The expression of transforming growth factor alpha (TGF-alpha) is consistently associated with the malignant transformation of oral mucosal tissues in both hamster and human. The cheek pouch of the Syrian hamster represents an ideal model to elucidate the role of TGF-alpha in epithelial cancer development. A prerequisite for such investigations at the molecular level is to obtain hamster-specific TGF-alpha molecular probes. Here we report the successful cloning of the hamster TGF-alpha cDNA from a hamster oral cancer cell line (HCPC-1) by the polymerase chain reaction technique using synthetic oligonucleotide primers based on human TGF-alpha cDNA sequence. Analysis of the nucleotide sequence of the newly isolated hamster cDNA encoding the portion of the mature TGF-alpha peptide revealed that it is 92.6% (139/150) homologous to that of the rat and 93.3% (140/150) homologous to that of the human sequences. The predicted hamster TGF-alpha amino acid sequence is 96% (48/50) similar to that of human, while 94% (47/50) similar to that of rat. Using this hamster TGF-alpha cDNA as a probe, molecular hybridization experiments revealed that it detects hamster TGF-alpha mRNA with approximately 40 times and approximately 5 times greater sensitivity than similar probes from human and rat origin respectively. This hamster TGF-alpha cDNA should be of great value as a probe to evaluate the role of TGF-alpha in the normal and pathological processes using the hamster as an experimental model.

Amino Acid Sequence↗
PubMed1991

Pharmacological properties of the new non-steroidal anti-inflammatory agent etodolac.

The anti-inflammatory, analgesic, antipyretic and ulcerogenic activities of etodolac (CAS 41340-25-4), a new nonsteroidal anti-inflammatory agent, were compared with those of indometacin and other anti-inflammatory drugs in experimental animals. Etodolac had a remarkable anti-inflammatory effect in various experimental models: ultraviolet erythema, carrageenin-induced edema and swelling of adjuvant arthritis. In these models, the effective dose of etodolac was several fold that of indometacin. Etodolac inhibited prostaglandin E2 formation in a concentration-dependent manner, and its inhibitory potency was about 1/5 of that of indometacin. Etodolac also caused marked inhibition of granuloma formation and leucocyte functions such as chemotaxis, lysosomal enzyme release and active oxygen generation. These effects of etodolac were observed at similar doses of indometacin. Etodolac suppressed inflammatory pain but not non-inflammatory pain, and had an antipyretic effect but did not lower normal rectal temperature. Etodolac had no effect on delayed hypersensitivity reactions and was much less ulcerogenic than indometacin. These results indicate that etodolac is a low ulcerogenic anti-inflammatory agent with suppressing activities on leucocyte functions to the same extent as indometacin and prostaglandin biosynthesis.

Animals↗
PubMed1991

[Effects of CR1505, a CCK antagonist, on pancreatic growth in hamsters].

The effects of CR1505, a CCK antagonist, on CCK-stimulated and normal pancreas were studied in Syrian golden hamsters. The CCK-stimulated trophic effect was inhibited by CR1505 in a dose-dependent manner, in which CR1505 100 mg/kg bw resulted in a complete inhibition of the weight of pancreas, the total pancreatic protein and DNA contents, compared to the control. Otherwise, CR1505 administration in doses of 25, 50, 100 mg/kg bw alone, didn't induce any significant changes among CR1505-treated groups and the control one. However, in the dose of 200 mg/kg bw, the weight of pancreas, the total pancreatic protein and DNA contents were significantly lower than control levels, suggesting pancreatic atrophy in the hamster. It's concluded that CR1505 is an effective CCK receptor antagonist that could inhibit the CCK-induced pancreatic trophic effect. Furthermore, CR1505 administration to normal pancreas brought out pancreatic atrophy, indicating that CCK seems to play an important role in the maintenance of normal pancreatic growth in hamsters.

Animals↗
PubMed1990

Two distinct cystatin species in rice seeds with different specificities against cysteine proteinases. Molecular cloning, expression, and biochemical studies on oryzacystatin-II.

Oryzacystatin (oryzacystatin-I) is a proteinaceous cysteine proteinase inhibitor (cystatin) in rice seeds and is the first well defined cystatin of plant origin. In this study we isolated cDNA clones for a new type of cystatin (oryzacystatin-II) in rice seeds by screening with the oryzacystatin-I cDNA probe. The newly isolated cDNA clone encodes 107 amino acid residues whose sequence is similar to that of oryzacystatin-I (approximately 55% of identity). These oryzacystatins have no disulfide bonds, and so could be classified as family-I cystatins; however, the amino acid sequences resemble those of family-II members more than family-I members. Oryzacystatin-I and -II are remarkably distinct in two respects: 1) their specificities against cysteine proteinases; and 2) the expression patterns of their mRNAs in the ripening stage of rice seeds. Oryzacystatin-I inhibits papain more effectively (Ki 3.0 x 10(-8) M) than cathepsin H (Ki 0.79 x 10(-6) M), while oryzacystatin-II inhibits cathepsin H (Ki 1.0 x 10(-8) M) better than papain (Ki 0.83 x 10(-6) M). The mRNA for oryzacystatin-I is expressed maximally at 2 weeks after flowering and is not detected in mature seeds, whereas the mRNA for oryzacystatin-II is constantly expressed throughout the maturation stages and is clearly detected in mature seeds. Western blotting analysis using antibody to oryzacystatin-II showed that, as is the case with oryzacystatin-I, oryzacystatin-II occurs in mature rice seeds. Thus, these two oryzacystatin species are believed to be involved in the regulation of proteolysis caused by different proteinases.

Amino Acid Sequence↗
PubMed1990

The alpha 1 (IX) collagen gene gives rise to two different transcripts in both mouse embryonic and human fetal RNA.

We have isolated and characterized portions of the alpha 1 (IX) collagen gene from mouse and human DNA. Nucleotide sequence analysis and comparison with the chicken gene suggest that the mammalian genes contain an alternative exon that is located within the intron between exons 6 and 7. Using oligonucleotide primers specific for exons 4, 8, and the alternative exon (exon 1*), we demonstrated by the polymerase chain reaction that embryonic mouse and fetal human RNAs contain two types of alpha 1(IX) collagen transcripts. One type of transcript does not contain the sequence encoded by exon 1*; the second type of transcript contains this exon. Both mouse and human alpha 1(IX) collagen genes give rise, therefore, to (at least) two mRNA transcripts.

Amino Acid Sequence↗
PubMed1989

Tissue-specific forms of type IX collagen-proteoglycan arise from the use of two widely separated promoters.

We demonstrate that the gene encoding an extracellular matrix component contains two widely separated promoters controlling the generation of different transcripts in a tissue-specific fashion. Two transcription start sites, about 20 kilobase pairs apart, in the alpha 1(IX) collagen gene are utilized to generate different forms of a collagen-proteoglycan (collagen IX) in chicken cartilage and cornea. Transcripts from the upstream site encode a large (266 amino acid residues) globular domain at the amino terminus of alpha 1(IX) chains, whereas the transcripts from the downstream site encode chains that lack this globular domain and contain a short alternative sequence. Transcripts from the upstream site are predominantly present in cartilage, and transcripts from the downstream site are predominantly used in cornea. The structural differences in collagen IX molecules that are synthesized as a consequence of the use of these two alternative transcription start sites in the alpha 1(IX) gene are likely to contribute to the differences in the macromolecular organization of the extracellular matrix in cartilage and cornea. Our finding provides a novel clue to answering the general question of what mechanisms are used to generate unique fibrillar patterns in different tissues.

Amino Acid Sequence↗
PubMed1989

The structure and expression of genes encoding serologically undetected HLA-C locus antigens.

Approximately 20 to 50% individuals in every race are untypable by human alloantisera for at least one allele of HLA-C locus and the surface expression of HLA-C locus Ag in such an individual (HLA-C blank Ag) remains unknown. To investigate the structure and the surface expression of HLA-C blank Ag, two genes (Cb-1 and Cb-2) encoding HLA-C blank Ag were cloned and their primary structures were determined and compared with other HLA-C locus genes. The similarity of amino acids between Cb-1 and Cw1 was the highest among HLA-C locus genes previously published. Five amino acid substitutions between these molecules were shown to be located on the beta-strand of alpha 1 and alpha 2 domains, suggesting that they might change the conformational allodeterminants on the alpha-helical region of Cw1 which were recognized by antibodies. On the other hand, Cb-2 was the closest to Cw2.2. Six of nine amino acid substitutions between these molecules were observed on alpha 1 and alpha 2 domains, whereas three other substitutions were located on the leader peptide, the alpha 3 domain and the transmembrane. Two substitutions (residues 73 and 163) of the alpha-helical region of the alpha 1 and alpha 2 domains and one (residue 16) of exposed loop may make new allodeterminants which are not recognized by anti-Cw2 sera as well as other alloantisera. The surface expression of these genes was examined on transfected mouse L cells and human B cell line. Both gene products were expressed stably on the surface of these cells. These results suggest that HLA-C blank Ag are most probably expressed on cells in HLA-C blank individuals and that the primary structures of these Ag, which were not detectable by the available alloantisera, may be incapable of generating corresponding alloantibodies.

Amino Acid Sequence↗
PubMed1989

[The influence of truncal vagotomy or surgical sympathectomy on the pancreatic trophic effect of trypsin inhibitor upon normal rats and major pancreatectomized rats].

The influences of truncal vagotomy or surgical sympathectomy on the pancreatic trophic effect of oral administration of synthetic trypsin inhibitor (FOY-305) were examined upon normal rats and 85% major pancreatectomized rats. On normal rats, oral administration of trypsin inhibitor increased pancreatic weight, DNA content RNA content, protein content, pancreatic weight/DNA, RNA/DNA and protein/DNA. This pancreatic trophic effect seemed to be consisted of hyperplasia and hypertrophy of pancreatic acinar cell. Under truncal vagotomy or surgical sympathectomy, this trophic effect was not diminished. On major pancreatectomized rats, oral administration of trypsin inhibitor also caused pancreatic trophic action, consisted of hyperplasia mainly. And truncal vagotomy or surgical sympathectomy did not decrease this action. These results suggested that oral administration of trypsin inhibitor might be a beneficial method for functional recovery of remnant pancreas after major pancreatectomy even under the denervated state.

Animals↗
PubMed1988

Cartilage type IX collagen-proteoglycan contains a large amino-terminal globular domain encoded by multiple exons.

Type IX collagen in cartilage consists of molecules composed of three genetically distinct polypeptide subunits. One of the subunits, alpha 2(IX), contains a covalently attached glycosaminoglycan side chain whereas a second subunit, alpha 1(IX), contains a large noncollagenous, amino-terminal domain called NC4. In this report, we describe for the first time the complete primary structure of this noncollagenous domain, based on cloning and sequencing of cDNA and genomic DNA as well as amino acid sequencing of tryptic peptides. Analysis of genomic clones has also allowed determination of the exon structure of NC4. Our results demonstrate that the noncollagenous, amino-terminal domain of alpha 1(IX) chains contains 266 amino acid residues (including the signal peptide) with 5 cysteinyl residues forming two disulfide bridges. The domain is basic with an estimated pI of 9.7, thus supporting the idea that it may participate in ionic interactions with polyanionic glycosaminoglycans in cartilage. Both the sequence and exon structure of the NC4 domain is unique among collagens and there is no obvious homology with the noncollagenous domains of other types of collagen, including the propeptides of fibrillar collagens.

Amino Acid Sequence↗
PubMed1988

A local pathophysiologic mechanism of the resorption of residual ridges: prostaglandin as a mediator of bone resorption.

The role of PG as a bone resorption mediator in RRR was investigated in the rat model and the following may be concluded from the data. 1. PG is suggested to be a mediator of the RRR. 2. The continuous and localized bone resorption in RRR may be caused by continuous synthesis of local PG. 3. PG producing cells and specific stimuli responsible for RRR are still unknown.

Alveolar Process↗
PubMed1988

Embryonic chicken cornea and cartilage synthesize type IX collagen molecules with different amino-terminal domains.

We have analyzed embryonic chicken cornea for the presence of type IX collagen mRNA and protein. Using RNA transfer blot analysis, we demonstrate that alpha 1(IX) and alpha 2(IX) mRNAs are expressed by corneal epithelial cells at the time that the primary stromal components are synthesized. The levels of the mRNAs decrease with increasing developmental age and are barely detectable at day 11 of development. In contrast, type IX collagen protein is detectable by immunofluorescence at days 5 and 6 and undetectable by day 8. Using probes specific for alpha 1(IX) and alpha 2(IX) mRNAs, we demonstrate that the size of alpha 2(IX) mRNA is the same in cornea as in chondrocytes, the major source of type IX collagen. However, the alpha 1(IX) mRNA is about 700 nucleotides shorter in the cornea than in cartilage because the corneal form of the mRNA does not contain the 5' region that encodes the non-triple-helical amino-terminal globular domain of cartilage type IX collagen. Therefore, corneal type IX collagen must lack this domain. This structural modulation of an extracellular matrix protein is likely to contribute to the functional differences between cartilage matrix and the early corneal stroma, both of which are rich in type II collagen.

Amino Acid Sequence↗
PubMed1987

Resorption of residual ridges (RRR) in rats.

The post-extraction resorption of residual ridges (RRR) is a major and largely unsolved health problem, probably of multifactorial etiology. In order for one to study the role of specific factors in the pathophysiology of RRR, the use of animal models is desirable. The purpose of this study was to establish a reliable animal model and a standardized assay system to measure RRR for future experiments. A new oblique cephalometric device was designed to take pairs of xeroradiographs on the right and left sides of the rat skull and mandible at a 45-degree angle to the horizontal plane. Preliminary studies confirmed the reproducibility of the technique. All molars were extracted with minimal trauma from the right maxilla and mandible in five male Sprague-Dawley rats (40 days old). Longitudinal cephalographic examinations were performed before and immediately after extraction and at two, four, eight, and 12 weeks after extraction. Alveolar bone resorption was measured on enlarged cephalographs (5.7 X) at a point mesial to the mandibular first molar. Sequential mean bone resorption was 0.8 +/- 0.2 mm (S.D.), 1.0 +/- 0.3, 1.3 +/- 0.3, and 1.5 +/- 0.4, respectively. Graphically, these findings produced bone loss curves similar to those observed in man. These results indicate that the rat model may be utilized in longitudinal studies of the resorption of the residual ridge.

Alveolar Process↗
PubMed1984

Laser-welded vs soldered nonprecious alloy dental bridges: a comparative study.

The high cost of gold alloy has caused the dental profession to begin substituting nonprecious alloy for the framework in porcelain fused to metal bridges. Especially in long-span bridges it may be advantageous to make multiple castings and then join them for a better fit. As opposed to the highly successful soldering of gold, soldered nonprecious alloy bridges have a great failure rate in the mouth. Removal of and remaking of the bridges is thus the result. This study compares nonprecious units that have been laser-welded with those conventionally soldered. Seven identical bridges of three units were cast in a popular alloy composed of 74-78% nickel, 12-15% chromium, 4-6% molybdenum, and 1.8% maximum beryllium. One served as a control, while the remaining six were all cut in the same place. Of these, three were soldered with a gas oxygen torch. The other three were welded with a Nd-YAG laser. Better and stronger joints unlikely to fracture in the mouth were found with the laser-welded specimen.

Chromium Alloys↗