Biomedical subjects

Y Murakami

Publications and source records attributed to Y Murakami.

At least 649 records · Page 36Linked to original sources

PubMed1992

Mutations of p53 gene and their relation to disease progression in B-cell lymphoma.

The alteration of p53 tumor suppressor gene was studied in 48 patients with B-cell lymphoma. A sequential combined technique of polymerase chain reaction-mediated single-strand conformational polymorphism (PCR-SSCP) or reverse transcription (RT)-PCR-SSCP and direct sequencing were used as a simple and sensitive approach to analyze nucleotide changes. By these methods, we identified 8 missense point mutations and 2 codon deletions in 9 of the 48 patients. These mutations were located in or close to the evolutionally highly conserved regions of the p53 gene. Eight of nine patients having p53 gene alterations were in advanced clinical stage (IV). It is the first report of p53 gene mutations in follicular and diffuse lymphoma. These observations suggest that the p53 gene alteration may play an important role in lymphomagenesis and/or disease progression in some types of B-cell lymphoma.

Base Sequence↗

PubMed1992

Antizyme, a protein induced by polyamines, accelerates the degradation of ornithine decarboxylase in Chinese-hamster ovary-cell extracts.

Ornithine decarboxylase (ODC), the key regulatory enzyme for polyamine biosynthesis, is known to have a short intracellular half-life, and antizyme, an ODC-binding protein induced by polyamines, has been suggested to be involved in the process of ODC degradation. In the present study we demonstrated that antizyme markedly accelerated ATP-dependent degradation of ODC in vitro in an extract from ODC-overproducing Chinese-hamster ovary cells.

Adenosine Triphosphate↗

PubMed1992

Human fibroblast cells synthesize and secrete nerve growth factor in culture.

Using our enzyme immunoassay system developed for recombinant hNGF, we examined the synthesis and secretion of human NGF (hNGF) by human fibroblast (WS-1) cells. The amount of the factor secreted by WS-1 cells increased linearly and a significant amount of NGF was detected in the conditioned medium of WS-1 cultures. WS-1 NGF showed properties identical to those of recombinant human NGF in immunoreactivity and molecular weight. An increase in cell density or the withdrawal of serum from the culture medium caused a drastic decrease in the rate of NGF secretion. These results suggest that WS-1 cells are able to synthesize and secrete hNGF in culture and that the synthesis/secretion is regulated in a growth phase-dependent manner.

Cell Division↗

PubMed1992

The replication of DNA containing the simian virus 40 origin by the monopolymerase and dipolymerase systems.

The influence of DNA polymerase (pol) alpha and DNA primase on SV40 DNA replication was examined in both the monopolymerase and dipolymerase systems. The synthesis of oligoribonucleotides in the monopolymerase and dipolymerase systems, followed by pulse labeling with deoxynucleoside triphosphates, yielded short Okazaki fragments approximately 35 nucleotides in length that were chased into full-length Okazaki fragments with time. In the presence of activator 1 and proliferating cell nuclear antigen (PCNA), but no pol delta, these short fragments hardly increased in size with time. DNA fragments of similar size (approximately 35 nucleotides) were previously observed in SV40 replication reactions carried out with crude extracts of HeLa cells in the presence of antibodies directed against PCNA (Bullock, P. A., Seo, Y.S., and Hurwitz, J. (1991) Mol. Cell. Biol. 11, 2350-2361). Thus, the pol alpha-primase complex appears to act processively for only a short distance. At high levels of pol alpha and primase, both short and long DNA products were formed in both systems. In the presence of limiting amounts of pol alpha and excess primase, the monopolymerase system inefficiently yielded longer length Okazaki fragments than those formed with excess pol alpha and primase, whereas the dipolymerase system yielded both short and long DNA fragments. In the presence of limiting amounts of primase and excess pol alpha, long products were formed in both systems, and virtually no short products accumulated. Thus, the ratio between the polymerase and primer ends available controls the size of the nascent product DNA strands. We examined whether PCNA, the T4 phage-encoded gene product 45 (T4 gp45), and the Escherichia coli beta subunit of DNA polymerase III (dnaN gene product) supported SV40 DNA replication and the elongation of single-stranded DNA-binding protein-coated singly primed DNA in reactions catalyzed by pol delta, T4 DNA pol, and E. coli DNA pol III*, respectively. In the presence of T4 gp44/62 and T4 gp32 (but not human single-stranded DNA-binding protein isolated from HeLa cells), T4 DNA pol was weakly activated by PCNA and the beta subunit in lieu of T4 gp45 in the elongation of singly primed phi X174 DNA. However, the other systems were specific for their analogous auxiliary factors. This specificity indicates the importance of protein-protein interactions.

Antibodies, Monoclonal↗

PubMed1992

Studies on the initiation of simian virus 40 replication in vitro: RNA primer synthesis and its elongation.

DNA primase-dependent synthesis of oligoribonucleotides 10-15 nucleotides long was observed in the presence of ATP, UTP, GTP, and CTP by using the purified components of the simian virus 40 (SV40) DNA replication system. The DNA primase-catalyzed reaction required the SV40 large tumor antigen (T antigen), DNA polymerase alpha (pol-alpha), the three-subunit human single-stranded DNA binding protein (HSSB), and topoisomerase I. The synthesis of small RNAs was unaffected by the addition of activator 1, proliferating cell nuclear antigen, and DNA polymerase delta, proteins that can support extensive leading-strand synthesis. The RNA primers were derived predominantly from transcription of the lagging-strand template, even after prolonged incubation, indicating that the leading strand did not serve as a template. When the four dNTPs were added after oligoribonucleotide synthesis, pol-alpha extended the RNA primers hybridized to SV40 DNA. Pulse-chase experiments revealed that the small RNA chains were elongated to Okazaki-sized products. T7 DNA polymerase was also shown to rapidly extend oligoribonucleotide primers in the presence of aphidicolin or antibodies against pol-alpha, conditions under which pol-alpha was markedly inhibited. These findings suggest that interactions between T antigen, pol-alpha-primase, and HSSB position the pol-alpha-primase complex on the lagging-strand template for RNA primer synthesis.

Antigens, Polyomavirus Transforming↗

PubMed1992

Distribution of tyrosine hydroxylase immunoreactive nerve fibers in the canine larynx.

The sympathetic innervation of the canine larynx was investigated using tyrosine hydroxylase (TH) immunohistochemistry. Many tyrosine hydroxylase immunoreactive (TH-IR) nerve fibers were observed around arteries and arterioles in the laryngeal mucosa and intrinsic laryngeal muscles. In the glandular region, TH-IR fibers were also found, with some of these fibers terminating around the basement membranes of the glandular cells. The quantity of TH-IR fibers in the mucosa differed among regions of the larynx. Many of these fibers could be found in the laryngeal surface of the epiglottis as well as the posterior glottis. These findings suggest that TH-IR fibers may directly innervate muscles in the intrinsic larynx.

Adrenergic Fibers↗

PubMed1992

Distribution of calcitonin gene-related peptide nerve fibers in the canine larynx.

Immunohistochemistry was used to investigate the distribution pattern of calcitonin gene-related peptide (CGRP) nerve fibers in the laryngeal mucosa, glands and intrinsic muscles of the dog. CGRP immunoreactive nerve fibers were found more frequently than substance P immunoreactive nerve fibers in every region of the larynx. In the epithelia, CGRP nerve fibers were mainly found in the epiglottis, arytenoid region and subglottis. Many taste buds were observed in the arytenoid region and were densely innervated by the CGRP nerve fibers. In the lamina propria, the plexus of CGRP nerve fibers was present, with some of these fibers associated with blood vessels. Laryngeal glands were also innervated by a few CGRP nerve fibers. In the intrinsic laryngeal muscles, abundant immunoreactivity was observed and many motor end-plate-like structures were found with CGRP immunoreactivity. These findings strongly suggest that CGRP plays an important role in all of the sensory, motor and autonomic nervous systems of the larynx.

Animals↗

PubMed1992

Detection of a common mutation of the catalase gene in Japanese acatalasemic patients.

Acatalasemia was one of the earliest described genetic enzyme defects. In 1990, a causal point mutation (a splicing mutation) was first reported in a Japanese patient with acatalasemia. In the present study, the polymerase chain reaction and single-strand conformation polymorphism analysis were used to determine whether the same point mutation was present in unrelated Japanese patients. The subjects studied were the previously examined acatalasemic female, her brother, who is hypocatalasemic, and two other unrelated acatalasemic patients. A single G to A point mutation at the fifth position of intron 4, identical to that previously found, was present in all the studied patients. This finding strongly suggests that only a single mutated allele has spread in the Japanese population.

Acatalasia↗

PubMed1992

Anomalous arrangement of the pancreaticobiliary ductal system without dilatation of the biliary tract.

A rare case of anomalous arrangement of the pancreaticobiliary ductal system without dilatation of the biliary tract (AAPBDS without DBT) associated with mucosal dysplasia of the biliary duct is described herein. A 53 year old male with a long history of diarrhea and right upper abdominal pain was diagnosed as having AAPBDS without DBT by endoscopic retrograde cholangiopancreatography and other examinations. Excision of the gallbladder and biliary duct with a Roux-en-Y hepatico-jejunostomy was performed and subsequent pathological examination of the surgical specimens showed mucosal hyperplasia of the gall-bladder and mucosal dysplasia of the biliary duct. Considering the dysplastic changes of the biliary duct as seen in our case, and the high incidence of AAPBDS without DBT developing into carcinoma of the biliary duct, being 12.2 per cent, we suggest that pancreaticobiliary ductal diversion with excision of the gallbladder and biliary duct should also be performed for AAPBDS without DBT. However, further pathological investigations concerning the excised biliary duct in AAPBDS without DBT will be need to be carried out.

Bile Ducts↗

PubMed1992

Mapping of the human GSPT1 gene, a human homolog of the yeast GST1 gene, to chromosomal band 16p13.1.

The GSPT1 gene, a human homolog of the yeast GST1 gene (formerly named GST1-Hs), was mapped on human chromosome 16p13.1 by a combination of nonradioactive in situ hybridization and Giemsa staining. Southern blot hybridization with a panel of human-rodent somatic cells confirmed the location of the GSPT1 gene on chromosome 16 and also showed the existence of a homologous gene on the X chromosome. A breakpoint for nonrandom chromosome rearrangements has been found in the region of GSPT1 in patients with acute nonlymphocytic leukemia.

Blotting, Southern↗

PubMed1992

Induction of protective immunity and neutralizing antibodies to pseudorabies virus by immunization of anti-idiotypic antibodies.

Xenogenic anti-idiotypic antibodies (anti-Id) were prepared in rabbits against three murine neutralizing monoclonal antibodies (MAbs) directed to pseudorabies virus glycoproteins. These anti-Id were highly specific to idiotopes on the corresponding MAb molecules. Because the binding of MAb to the corresponding anti-Id was inhibited by the addition of viral envelope protein, these anti-Id seemed to contain a subpopulation of antibodies against the antigen-combining site (paratope) or the region related to the paratope of the MAb molecules. One of the anti-Id to a MAb directed against glycoprotein gp50 induced neutralizing antibodies to PrV. Mice immunized with the anti-Id were protected from lethal infection of PrV.

Animals↗

PubMed1992

Molecular design and catalytic function of a B12-enzyme mimetic.

Developing artificial holoenzymes requires attention to the molecular design, not only of the active site, but also of its microenvironment, which in the naturally occurring enzyme is provided by the apoprotein. Microenvironmental effects play a major role in determining the catalytic performance of an enzyme. Using the development of a B12-dependent holoenzyme mimetic as an example, the important factors and concepts underlying the approaches to developing an artificial holoenzyme are discussed.

Amino Acid Isomerases↗

PubMed1992

Mapping of the gene family for human heat-shock protein 90 alpha to chromosomes 1, 4, 11, and 14.

The HSP90 family of heat-shock proteins (encoded by genes for HSP90 alpha and beta) constitutes one of the major groups of proteins that are synthesized at increased rates in response to heat and other forms of stress. We previously isolated two distinct cDNA clones for HSP90 alpha from human peripheral blood lymphocytes and from HeLa cells transfected with the adenovirus E1A gene, respectively. To determine the organization of this complex multigene family in the human genome, we used three complementary approaches: Southern analysis of a panel of human/hamster somatic cell hybrids, molecular cloning of the cosmid HSP90 alpha clones from libraries prepared with DNAs from human lymphoblastoid cells, and in situ hybridization to human chromosomes. We demonstrate here that nucleotide sequences that encode HSP90 alpha map to human chromosomes 1q21.2-q22, 4q35, 11p14.1-p14.2, and 14q32.3. The chromosomal mapping of the loci, HSPCAL1, HSPCAL2, HSPCAL3, HSPCAL4, and the characterization of the respective genes should facilitate clarification of the organization of this gene family and lead to a better understanding of the biological functions of the gene product.

Animals↗

PubMed1992

Effects of fatty acyl-coenzyme A esters on prostaglandin synthesis in rabbit kidney medulla microsomes.

The effects of fatty acyl-coenzyme A (CoA) esters (palmitoyl-, stearoyl-, oleoyl-, linoleoyl- and arachidonoyl-CoA) on the synthesis of prostaglandins (PGs) in rabbit kidney medulla microsomes were examined. Medulla microsomes were incubated with arachidonic acid in 0.1 M-Tris/HCl buffer (pH 8.0) containing reduced glutathione and hydroquinone and the formed PGE2, PGF2 alpha and PGD2 were measured by high-pressure liquid chromatography using 9-anthryldiazomethane for derivatization. Under our incubation conditions rabbit kidney medulla was found to produce PGE2 mainly. The addition of fatty acyl-CoA esters inhibited total PG formation (the sum of PGE2, PGF2 alpha and PGD2) in a dose-dependent manner. Palmitoyl-, stearoyl- and oleoyl-CoA were about 10 times more potent than linoleoyl- and arachidonoyl-CoA as inhibitors of total PG formation. Linoleic acid was slightly more effective than linoleoyl-CoA, while palmitic acid had no influence on PG formation. All the fatty acyl-CoA esters inhibited the formation of PGE2. Simultaneously, the production of PGF2 alpha and PGD2 was increased. These results suggest that the CoA derivatives of palmitic, stearic and oleic acids have the potential to modulate PGE2, PGF2 alpha and PGD2 synthesis by affecting the activities of both-cyclooxygenase and endoperoxide E2 isomerase.

Acyl Coenzyme A↗

PubMed1992

Chemical modification of proteins under high pressure. Preparation of ferrocene-attached bovine serum albumin and glucose oxidase.

High hydraulic pressure was used for denaturing proteins during chemical modifications. Bovine serum albumin and glucose oxidase were selected as the first targets of this unique technique and the ferrocene group was introduced into them, to obtain a macromolecular electron mediator and a self-electron-mediating oxidase, respectively. The result was compared with those obtained under non-denaturing conditions and under urea-denatured conditions. As for the number of ferrocene group linked to the protein, the pressure denaturation is superior to chemical denaturants, where ferrocenecarboxyaldehyde was used as the modifier. In both proteins the ferrocene group seemed to be introduced mainly inside the molecules with the pressure method, as the native conformation of the protein was restored when the high pressure was removed.

Ferrous Compounds↗

PubMed1992

Generation of 19 STS markers that can be anchored at specific sites on human chromosome 21.

Sequence-tagged sites (STSs) are short stretches of DNA that can be specifically detected by the polymerase chain reaction (PCR) and can be used to construct long-range physical maps of chromosomal DNA. These STSs can be detected by PCR assays developed by reference to data obtained from the sequencing of restriction fragment length polymorphism-DNA markers for chromosome 21, which were derived from recombinant lamba-phage and plasmid clones made from DNA of a human-hamster hybrid cell line. In this report, we describe the generation of 19 new STSs that are specific for human chromosome 21.

Base Sequence↗

PubMed1992

Peroxidase and coupling activities of thyroid peroxidase in benign and malignant thyroid tumor tissues.

The coupling activity of thyroid peroxidase (TPO) in thyroid glands from patients with benign adenoma, papillary carcinoma, and diffuse goiter (Graves' disease) was measured for the first time, in addition to the peroxidase activity of these tissues. The peroxidase activity of TPO in the mitochondria-microsomes fraction was measured with guaiacol or iodide as the second substrate. In the case of papillary carcinoma, the mean protein-based specific activity obtained by the guaiacol assay was about 1/7 of that of diffuse goiter. The iodide oxidation activity of carcinoma was very low, about 1/25 [corrected] of that in diffuse goiter and 1/70 of that in adenoma. The peroxidase activity in adenoma was almost similar in the guaiacol oxidation assay and approximately one half in the iodide oxidation assay as compared with that in diffuse goiter. There was a close correlation between the guaiacol and iodide oxidation assays in individual patients with adenoma and diffuse goiter, but not in patients with papillary carcinoma. The coupling activity of TPO was measured with thyroglobulin purified from pooled toxic diffuse goiters and chemically iodinated to contain little additional T3 and T4. The specific coupling activity of TPO in mitochondria-microsomes from carcinoma was significantly lower (about 1/5) than that of diffuse goiter, and the activity in adenoma was not significantly different (about 1/2) from that of diffuse goiter. The data of coupling activities has a close correlation with that of peroxidase activities in individual patients with adenoma but not in patients with carcinoma. Based on these findings, the qualitative abnormality of TPO and its relation to the cold 123I scintigram in thyroid tumors are discussed.

Adenoma↗

PubMed1992

Absence of activating mutations in the transmembrane domain of the c-erbB-2 protooncogene in human lung cancer.

The rat neu gene is known to be activated by a point mutation in its predicted transmembrane domain. Overexpression of the human homologue of neu, the c-erbB-2 gene, in human lung cancer has been reported, and a similar activating point mutation has been suggested. Therefore, we tested for possible aberrations of the c-erbB-2 gene in the region of the transmembrane domain in surgical specimens of human primary lung cancer from 190 patients, and also examined 24 metastases and 26 specimens of noncancerous portions of the lung of the same patients. Single-strand conformation polymorphism analysis of polymerase chain reaction products revealed no point mutations in the target domain in any of these specimens.

Base Sequence↗