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Biomedical subjects

M Saeki

Publications and source records attributed to M Saeki.

At least 37 records · Page 2Linked to original sources
PubMed2000

Differentiation-associated expression and intracellular localization of cyclin-dependent kinase inhibitor p27KIP1 and c-Jun co-activator JAB1 in neuroblastoma.

Neuroblastoma is a unique pediatric cancer, which spontaneously regress in some infants and undergo maturation in older children. The cyclin-dependent kinase inhibitor p27KIP1 negatively control cell cycle progression and its expression is reported to be associated with differentiation and prognosis of some human cancers. To examine whether p27KIP1 is involved in differentiation of neuroblastomas, expression and localization of p27KIP1 in 30 cases of neuroblastic tumors were determined with immunohistochemistry. p27KIP1 was expressed in all cases, but staining intensity and intracellular localization varied in association with tumor differentiation. Primitive small round neuroblasts showed negative or only weak nuclear staining, while differentiating tumor cells displayed a novel, intense cytoplasmic positivity besides the nuclear staining, and mature ganglion cells showed intense positive reaction confined to the nucleus. A neuroblastoma cell line TGW was also immunostained positively for p27KIP1 in the cytoplasm after differentiation induction, and western blot analysis revealed an increase of p27KIP1 in these cells, corroborating the in vivo observations. JAB1, which is thought to bind p27KIP1 and transport it from the nucleus to the cytoplasm for proteasome/ubiquitin-mediated degradation, was found to be localized both in the cytoplasm and the nucleus in undifferentiated and differentiating tumors whereas located predominantly in the nucleus of differentiated tumor cells. These data indicate that the cytoplasmic localization of p27KIP1 in the process of differentiation is due to upregulation of p27KIP1 synthesis and subsequent degradation and suggest a role of p27KIP1 in differentiation of neuroblastoma.

Blotting, Western↗
PubMed2000

Pharmacokinetics and biological fate of 3-(2,2, 2-trimethylhydrazinium)propionate dihydrate (MET-88), a novel cardioprotective agent, in rats.

In this study, we examined the disposition, metabolism, and excretion of a novel cardioprotective agent, 3-(2,2, 2-trimethylhydrazinium)propionate dihydrate (MET-88), in rats. The disposition of MET-88 after oral and i.v. administration of 2, 20, and 60 mg/kg indicated that the pharmacokinetics of MET-88 were nonlinear. The profiles of radioactive MET-88 and total radioactivity in plasma were consistent at doses of 20 and 60 mg/kg. However, at 2 mg/kg, the plasma MET-88 levels were obviously lower than the total. The excretion of radioactivity after oral administration of MET-88 indicated that increasing doses led to a shift from exhaled CO(2) to urinary excretion as the major excretion route. Major metabolites in plasma after oral administration of MET-88 were glucose, succinic acid, and 3-hydroxypropionic acid, and in vitro studies revealed that MET-88 was converted to 3-hydroxypropionic acid by gamma-butyrobetaine hydroxylase (EC 1.14. 11.1). An isolated liver perfusion system modified to trap CO(2) gas was used to examine the excretion pathway of MET-88. [(14)C]CO(2) gas was decreased by the addition of iodoacetic acid, DL-fluorocitric acid, or gamma-butyrobetaine to this system, and subsequent thin-layer chromatography analyses of perfusates revealed that MET-88 was first converted to 3-hydroxypropionic acid by gamma-butyrobetaine hydroxylase and then was biosynthesized to glucose and metabolized to CO(2) gas via the glycolytic pathway and tricarboxylic acid cycle.

Animals↗
PubMed1999

Association of two nuclear proteins, Npw38 and NpwBP, via the interaction between the WW domain and a novel proline-rich motif containing glycine and arginine.

We have previously reported a nuclear protein possessing a WW domain, Npw38 (Komuro, A., Saeki, M., and Kato, S. (1999) Nucleic Acids Res. 27, 1957-1965). Here we report a Npw38-binding protein, NpwBP, isolated from HeLa cell nuclear extracts and its characterization using a cloned cDNA. NpwBP contains two proline-rich regions that are capable of binding to the WW domain of Npw38. The binding analysis using an oligopeptide-immobilized membrane revealed that the WW domain of Npw38 preferentially recognizes a short proline-rich sequence, PPGPPP, surrounded by an arginine residue, so we named it a PGR motif. Localization analysis using green fluorescent protein fusion protein and immunostaining showed that Npw38 and NpwBP are colocalized in the same subnuclear region. Coimmunoprecipitation experiments confirmed the association between Npw38 and NpwBP, which were expressed as epitope-tagged forms in COS7 cells. Furthermore, the N-terminal region of NpwBP has binding ability for poly(rG) and G-rich single-stranded DNA. These results suggest that NpwBP is a physiological ligand of Npw38 and that the Npw38-NpwBP complex may function as a component of an mRNA factory in the nucleus.

Amino Acid Sequence↗
PubMed1999

Morphine prevents peroxynitrite-induced death of human neuroblastoma SH-SY5Y cells through a direct scavenging action.

N-ethyl-2-(1-ethyl-2-hydroxy-2-nitrosohydrazino)-ethanamine (NOC12), a nitric oxide donor, 3-morpholinosydnonimine (SIN-1), a generator of peroxynitrite (ONOO-), and peroxynitrite induced cell death accompanied by DNA fragmentation in human neuroblastoma SH-SY5Y cell cultures. Morphine prevented the cell death induced by SIN-1 or peroxynitrite, but not that induced by NOC12. The protective effect of morphine was concentration-dependent (10-100 microM), but was not antagonized by naloxone. The selective ligands for opioid receptor subtypes, [D-Ala2, N-Me-Phe4, Gly-ol5]enkephalin (DAMGO, micro-opioid receptor agonist), [D-Pen2,5]enkephalin (DPDPE, delta-opioid receptor agonist) and trans-(+/-)-3,4-dichloro-N-methyl-N-(2-[1-pyrrolidinyl]-cyclohexyl)benze neacetamide (U-50488, kappa-opioid receptor agonist) even at the concentration of 100 microM did not prevent the cell death induced by SIN-1. From measurement of the absorbance spectrum of peroxynitrite, the decomposition of peroxynitrite in 0.25 M potassium phosphate buffer (pH 7.4) was very rapid and complete within seconds. However, the absorbance was very stable in the presence of morphine. In addition, morphine inhibited peroxynitrite-induced nitration of tyrosine in a concentration-dependent manner. These results indicate that morphine rapidly reacts with peroxynitrite. The present study showed that morphine prevented peroxynitrite-induced cell death through its direct scavenging action, suggesting that morphine can protect cells against damage caused by peroxynitrite.

Cell Death↗
PubMed1999

Npw38, a novel nuclear protein possessing a WW domain capable of activating basal transcription.

We have found a novel cDNA encoding a 265 amino acid protein possessing a WW domain in our full-length cDNA bank. The WW domain was sandwiched between an acidic region and an acidic-basic amino acid repetitive region. In vitro transcription/translation of the cDNA produced a 38 kDa product that was also found in the cell lysate by western blot analysis. Thus this protein is named the nuclear protein containing a WW domain with a molecular mass of 38 kDa, Npw38. Immunofluorescence studies and expression of a fusion protein to a green fluorescent protein revealed that this protein is localized in the nucleus. Npw38 was shown to be capable of binding to a poly(rG) resin. Interestingly, the WW domain of Npw38 was found to function as a transcriptional activator in CHO cells using the GAL4 DNA-binding fusion system. Furthermore, the WW domains of human YAP and Pin1 were demonstrated to have a similar transcription-promoting activity. Combined mutation of the conserved first and second Trp residues and a hydrophobic triplet of TyrTyrTrp in the WW domain of Npw38 abolished the transcription-promoting activity, but single mutations of these sites did not. These results suggest that some WW domains potentially possess transcription-promoting activity in mammalian cells.

Amino Acid Sequence↗
PubMed1999

In vitro binding study of adaptor protein complex (AP-1) to lysosomal targeting motif (LI-motif).

Lysosomal membrane glycoproteins carry targeting information in cytoplasmic regions. Two distinct targeting motifs in these regions, GY (glycine-tyrosine) and LI (leucine-isoleucine), have been identified and characterized. Accumulating evidence suggests that the adaptor complexes (AP-1, AP-2, and AP-3) recognize this information in cytoplasmic tails of transmembrane proteins. Here we report two different in vitro analyses (affinity beads and surface plasmon resonance) which revealed specific interaction between the cytoplasmic tail of LGP85 and AP-1 but not so with AP-2. We also noted requirement of the LI motif of the LGP85 tail in binding to the AP-1 complex. Our data and others which indicated the binding of AP-3 to the LIMP II (synonym of LGP85) tail suggest that the cytoplasmic tail of LGP85 interacts with AP-1 at the trans-Golgi network (TGN) and AP-3 at late endosomes, respectively. We propose that this sequential interaction between the lysosomal targeting signal and distinct APs along its transport pathway is responsible for the critical sorting of lysosomal membrane proteins and/or the potential proofreading system of mistargeted molecules.

Adaptor Protein Complex alpha Subunits↗
PubMed1999

Congenital absence of the portal vein in a boy.

Congenital absence of the portal vein (CAPV) is a malformation that is generally thought to be limited to females. We encountered an 11-year-old boy with this malformation. In 17 previously reported cases of CAPV, 2 were male. Three male patients, including our case, were Abernethy type Ib malformation. They had no associated liver tumour and two had no additional congenital abnormality. Conversely, 13 of the 15 female patients had congenital abnormalities and 6 had liver mass lesions.

Child↗
PubMed1999

Analysis of 1,992 patients with anorectal malformations over the past two decades in Japan. Steering Committee of Japanese Study Group of Anorectal Anomalies.

BACKGROUND/PURPOSE: This report describes the results of a group study of the Japanese Study Group of Anorectal Anomolies (JSGA) to determine the relative incidence of specific types of anorectal anomaly in Japan, and includes discussion of rectourethral fistula regarding the relationship between the levels of the fistula and blind end of the rectum, low type deformity, rare types, and associated anomalies. METHODS: A total of 1,992 patients (1,183 boys and 809 girls) registered from 1976 to 1995 were analyzed. RESULTS: High-type deformities accounted for 26.0% of cases, intermediate 10.7%, low 57.2%, miscellaneous 4.5% and unclassified 1.8%. The most frequent deformity was male anocutaneous fistula (n = 364), followed by male rectourethral fistula (n = 333), and female anovestibular fistula (n = 241). There were 42 rectovesical fistulas in boys and 93 rectocloacal fistulas in girls. Covered anus complete occurred at the same frequency (10.1% of low deformities) as covered anal stenosis. In rectourethral fistula, the blind end of the rectum lay at or above the level of the P-C line in 40.3% of cases, at or above the M line in 39.6% and at the vicinity of the I line in 20.2%, respectively. There was no parallel relationship between the site of the fistula opening and the level of the rectal pouch. The overall incidence of patients having one or more associated anomalies was 45.2%: 70.6% in high deformity, 60.7% in intermediate, and 31.3% in low. The rate of association of Down's syndrome with deformities without fistula (40.3%) was significantly higher than with deformities with fistula (0.3%). CONCLUSIONS: Rectovesical fistula and covered anus complete were not infrequent deformities in this series. We consider that at least 20% of rectourethral fistula should be categorized as intermediate or low deformity from the viewpoint of the position of the rectal pouch. A significant preponderance of Down's syndrome in the deformities without fistula suggests that further investigation of associated anomalies in comparision with other congenital diseases may provide insights into the pathogenesis of anorectal malformation in the field of molecular genetics.

Anal Canal↗
PubMed1999

p130cas is a cellular target protein for tyrosine nitration induced by peroxynitrite.

We found that the exposure of human neuroblastoma SH-SY5Y cells to the peroxynitrite donor 3-morpholinosydnonimine (SIN-1) induced tyrosine nitration of a 130-kDa protein, and prevented tyrosine phosphorylation of the 130-kDa protein. The focal adhesion protein p130cas was identified as a component of the 130-kDa protein using specific antibody. These results suggest that p130cas is a new target protein for nitration induced by SIN-1.

Crk-Associated Substrate Protein↗
PubMed1999

On preventing sugar-coated tablets from browning.

The phenomenon of browning occurs gradually in the white sugar-coating layer (comprised of sucrose, talc, and powdered acacia) when the coating is applied on a large scale. We found that this phenomenon is negligible on sugar-coated tablets when they are prepared on a small scale. The smoothing layer prepared on a small scale is nearly as opaque as the subcoating layer. Conversely, the smoothing layer produced on a larger scale is semitransparent. In large-scale operations, the conditions required to make the smoothing layer opaque were established, and it was demonstrated that this method can restrict the browning phenomenon. It is considered that the nitrogen-containing contaminants in powdered acacia may react with heat-inverted sucrose (the Maillard reaction) to make brown substances in the smoothing layer and that the opaque appearance of the layer conceals the color accumulation of the brown substances in the smoothing layer and therefore restricts the browning phenomenon.

Carbohydrates↗
PubMed1999

Multi-ubiquitination of a nascent membrane protein produced in a rabbit reticulocyte lysate.

During a large-scale in vitro translation analysis of a human full-length cDNA bank, we found many clones producing in vitro translation products showing ladder bands on a fluorogram with the equidistance of about 9 kDa at the position larger than the molecular mass expected from the open reading frame. We have analyzed a clone showing a typical pattern of the ladder bands. This clone encoded a 188-amino acid polypeptide containing a putative transmembrane domain. A green fluorescent protein-tagged polypeptide expressed in COS7 cells was localized in the endoplasmic reticulum and the Golgi apparatus. The ladder bands were observed in a rabbit reticulocyte lysate system, but not in a wheat germ extract system. Addition of the glutathione S-transferase-fused ubiquitin into the lysate caused upward shifts of the ladder bands. Addition of microsomal membranes prevented the formation of the ladder bands. Time course experiments demonstrated that the in vitro translation products increased in the presence of microsomal membranes, but were gradually degraded in their absence. These results suggest that the ladder formation resulted from the ubiquitination of misfolded polypeptide that failed to translocate to its proper position, and that an exclusion mechanism of misfolded membrane protein works in the rabbit reticulocyte lysate system.

Amino Acid Sequence↗
PubMed1998

Anti-emetic effects of a novel NK-1 receptor antagonist HSP-117 in ferrets.

We have developed a non-peptide compound, HSP-117, antagonist of the tachykinin NK-1 receptor. Binding of 3H-substance P (SP) to the membranes of IM-9 cells was inhibited by the antagonists HSP-117 and CP-99,994, the inhibitory activity of HSP-117 being about 50-fold that of CP-99,994. The SP-induced firing responses of single neuron activity in slices of the nucleus tractus solitarius of ferrets were inhibited by 10 microM HSP-117. Intracerebroventricular injection of HSP-117 significantly inhibited retching and vomiting induced by copper sulphate and morphine and the inhibitory effect of HSP-117 on emesis was greater than that of CP-99,994. These results indicate that (1) HSP-117 is a potent anti-emetic agent, blocking NK-1 receptors in the nucleus tractus solitarius and (2) NK-1 receptors in the nucleus tractus solitarius play an important role in emesis induced by broad-spectrum emetic stimuli.

Animals↗
PubMed1998

cDNA cloning and functional analysis of p28 (Nas6p) and p40.5 (Nas7p), two novel regulatory subunits of the 26S proteasome.

We employed cDNA cloning to deduce the complete primary structures of p28 and p40.5, two novel subunits of PA700 (also called 19S complex), a 700 kDa multisubunit regulatory complex of the human 26S proteasome. These polypeptides consisted of 226 and 376 amino acids with calculated molecular masses of 24428 Da and 42945 Da, and isoelectric points of 5. 68 and 5.46, respectively. Intriguingly, p28 contained five conserved motifs known as 'ankyrin repeats', implying that this subunit may contribute to interaction of the 26S proteasome with other protein(s). Computer-assisted homology analysis revealed high sequence similarities of p28 and p40.5 with yeast proteins, termed Nas6p and Nas7p (non-ATPase subunits 6 and 7), respectively, whose functions are as yet unknown. Disruption of these yeast genes, NAS6 and NAS7, had no effect on cell viability, indicating that neither of the two subunits is essential for proliferation of yeast cells. However, the NAS7, but not NAS6, disruptant cells caused high sensitivity to heat stress, being unable to proliferate at 37 degreesC.

Adenosine Triphosphatases↗
PubMed1998

Comparison of clinical features and prognosis of cardiac sarcoidosis and idiopathic dilated cardiomyopathy.

In the present study, clinical findings of 15 patients with cardiac sarcoidosis presenting as dilated cardiomyopathy were compared with those of 30 consecutive patients with idiopathic dilated cardiomyopathy. The sarcoidosis patients had different clinical features, including female predominance, a high incidence of grave conduction disturbance and abnormal wall thickness, uneven wall motion abnormalities, and perfusion defects preferentially affecting the anteroseptal and apical regions, and poor prognosis compared with those with idiopathic dilated cardiomyopathy.

Adult↗
PubMed1998

A new NEDD8-ligating system for cullin-4A.

NEDD8 is a ubiquitin (Ub)-like protein. Here we report a novel ubiquitinylation-related pathway for modification by NEDD8. NEDD8 was activated by an E1 (Ub-activating enzyme)-like complex, consisting of APP-BP1 and hUba3 with high respective homologies to the amino- and carboxy-terminal regions of E1 and then linked to hUbc12 (a human homolog of yeast Ub-conjugating enzyme Ubc12p). The major target protein modified by NEDD8 was found to be Hs-cullin-4A (Cul-4A), a member of the family of human cullin/Cdc53 proteins functioning as an essential component of a multifunctional Ub-protein ligase E3 complex that has a critical role in Ub-mediated proteolysis.

Amino Acid Sequence↗
PubMed1998

Longitudinal follow-up of pulmonary function after lobectomy in childhood - factors affecting lung growth.

We examined the changes in pulmonary function values in 27 patients who underwent a lobectomy due to cystic lung disease and compared the results regarding such factors as disease type, age at operation, and preoperative infections. Percent vital capacity (%VC) decreased immediately after lobectomy, but recovered to normal values within 2 postoperative years and remained within or above the normal range. The ratio of residual volume to total lung capacity (RV/TLC) rose temporally with the increase in %VC, but then remained normal after 2 postoperative years. There was no difference in %VC and RV/TLC between diseases, while bronchial atresia showed a significantly lower correlation with percent of forced expiratory volume at 1 s. The older group operated upon at over 4 years of age and the group that had infections before operation showed relatively low %VC and high RV/TLC. Some patients demonstrated extremely low %VC along with funnel chest deformities. Our study suggests that overinflation of the remaining lung compensates VC in the early period after lobectomy while subsequently alveolar multiplication occurs. Factors affecting compensatory lung growth were considered to be operation later than 4 years of age, preoperative infection, and a thoracic deformity.

Child↗