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Y Mitsui

Publications and source records attributed to Y Mitsui.

At least 145 records · Page 8Linked to original sources
PubMed1996

Development of a competitive enzyme-linked immunosorbent assay for diethylcarbamazine.

A sensitive and reproducible competitive enzyme-linked immunosorbent assay (ELISA) for the determination of the concentration of diethylcarbamazine (DEC) in biological fluids was developed. Since DEC has no functional group to conjugate with bovine serum albumin (BSA), N-(2-aminoethyl)-N-ethyl-4-methyl-1-piperazinecarboxamide (DEC-NH2) was first synthesized. This compound was then converted to carboxyl DEC (DEC-COOH) and conjugated to BSA and to poly-L-lysine for use as immunogen and solid-phase marker, respectively. The competitive ELISA was conducted by simultaneously incubating DEC with mouse anti-DEC antiserum over DEC-poly-L-lysine solid phase. Subsequently, the binding of anti-DEC antibody was detected by using sheep anti-mouse IgG peroxidase conjugate as a tracer. The reliability, determined by the coefficient of variation for inter and intra-assay, was satisfactory. The cross-reactivities of anti-DEC antibodies with DEC metabolites, related compounds and ivermectin were negligible. Using this assay, DEC levels were easily determined in serum of Mongolian jirds (Meriones unguiculatus) up to 4 hours following a single dose of DEC citrate base (100 mg/kg of body weight) via intraperitoneal route.

Animals↗
PubMed1996

Involvement of two basic residues (Lys-17 and Arg-39) of mouse lung carbonyl reductase in NADP(H)-binding and fatty acid activation: site-directed mutagenesis and kinetic analyses.

Mouse lung carbonyl reductase, a member of the short-chain dehydrogenase/reductase (SDR) family, shows a strong coenzyme preference for NADP(H) over NAD(H), and is uniquely activated by fatty acids. Previous chemical modification and X-ray crystallography studies show that interactions responsible for the coenzyme specificity include salt linkages between the 2'-phosphate of NADPH and side-chains of Lys-17 and Arg-39 of the enzyme. Although Arg-39 is highly conserved in NADP(H)-dependent enzymes of the SDR family, Lys-17 is substituted with Arg in about half of the NADP(H)-dependent enzymes. The present study shows that mutations of Lys-17 to His (K17H) or Ser (K17S) and of Arg-39 to Ala (R39A) bring about decreases (from 5 to 90-fold) of the affinities for NADP(H), but minor changes in the affinity for NAD+. The binding energy arising from the mutations on the binding of the 2'-phosphate of NADP+ was decreased by 38-66% from the value of 4.8 kcal/mol calculated for the wild-type enzyme. In contrast, the mutation of Lys-17 to Arg (K17R) had little effect on the kinetic or thermodynamic properties. The activation by fatty acids was completely attenuated by the mutations of K17H and K17S, but not by K17R or R39A. These results indicate that the 2'-phosphate group of NADP(H) is recognized by both Lys-17 and Arg-39, of which Lys-17 is a component of the binding site for the activator, probably interacting with the negatively charged carboxylate group of fatty acids, and also suggest that the existence of a positively charged residue (either Lys or Arg) at position 17 is required for both NADP(H) specificity of the SDR family enzymes and fatty acid activation of the pulmonary carbonyl reductase.

Alcohol Oxidoreductases↗
PubMed1996

Simple and sensitive enzyme-linked immunosorbent assay for ivermectin.

A sensitive and reproducible enzyme-linked immunosorbent assay (ELISA) for the determination of the concentration of ivermectin (IVM) in biological fluids was developed. A conjugate of IVM on bovine serum albumin and poly-L-lysine was used to produce antibodies in rabbits and served as a solid-phase marker for titration of antibodies, respectively. The competitive ELISA was conducted by simultaneously incubating IVM and IVM-biotin conjugate with anti-IVM antiserum over goat anti-rabbit IgG (Fc) and then determining the amount of bound IVM-biotin with avidin-peroxidase conjugate as a tracer. The coefficient of variation for the assay was less than 10% in the range of 0.3-10 ng/ml. The limit of detection was 0.1 ng/ml. The cross-reactivities of anti-IVM antiserum with some anthelmintic drugs were negligible. Using this ELISA, serum levels of IVM were easily determined in Mongolian jirds (Meriones unguiculatus) up to 72 hr following a single oral dose of 500 microgram/kg of body weight.

Animals↗
PubMed1996

[Vasoactive intestinal contractor (VIC)/mouse ET-2 and VIC receptor: biological activity, gene expression, and specific receptor].

Using molecular biology techniques with the Endothelin (ET) cDNA as a probe, we discovered a novel peptide, vasoactive intestinal contractor (VIC). VIC differed from ET (= ET-1) in 3 amino acid residues. Synthetic VIC had in vivo pressor and in vitro vasoconstrictor activity such as that of ET. Northern blot analysis, however, indicated the VIC gene to be expressed in the intestine. Furthermore, VIC evoked stronger contractile response in ileum than ET. VIC may thus possibly be reasonably classified as a gut peptide. From the cDNA sequence analysis, the mature VIC is predicted to be produced via an intermediate from the deduced prepro VIC.

Amino Acid Sequence↗
PubMed1996

[Intraventricular arachnoid cyst--on the origin of intraventricular arachnoid cysts].

Arachnoid cysts very rarely occur within the ventricular system, where no arachnoid tissue exists. We present three cases of intraventricular arachnoid cyst with special reference to its origin. The first patient was a 5-year-old boy who complained of headaches and enlargement of his head. A CT scan revealed obstructive hydrocephalus and a large cystic lesion in the right lateral ventricle. The symptoms resolved after fenestration of the cyst and cystoperitoneal shunt. The second patient was a 49-year-old woman who complained of headache and numbness in her left upper extremity. A CT scan and MRI revealed a large cyst in the trigone of the right lateral ventricle. Fenestration of the cyst wall and cystoperitoneal shunt were performed relieving her complaints. The third patient was a 42-year-old man who complained of frequent seizures and dizziness. A CT scan and MRI demonstrated a moderate size cystic mass in the inferior horn of the right lateral ventricle. The symptoms were improved by partial resection of the cyst wall. Immunohistochemical studies and light microscopy confirmed that the cyst walls were composed of arachnoid membrane, implying that the cysts were arachnoid cysts. CT and MRI in these three cases showed widening of the choroidal fissure bordering the cyst wall, occasionally involving a part of the protruding cyst wall. On enhanced CT and MRI, the choroid plexus in the trigone of ipsilateral lateral ventricle was displaced anterolaterally, implying that the cysts had grown from outside the choroid plexus. Postoperative MRI demonstrated the shrunken cyst wall attached to the choroidal fissure. The surgical findings in case 3 also showed that the cyst wall was attached firmly to the choroid plexus. These findings appeared to indicate that the intraventricular arachnoid cyst originated from the arachnoid layer drawn into the choroidal fissure with choroidal vascular mesenchyme.

Adult↗
PubMed1996

[Neuroradiological findings of sporadic olivopontocerebellar atrophy with marked laterality and degenerative changes in the corticopontine tract].

We report a case of sporadic olivopontocerebellar atrophy (OPCA) with marked laterality of cerebellar atrophy and degenerative changes in the corticopontine tract. A 35-year-old man was admitted to our hospital for evaluation of titubation, gait disturbance, dysarthria, and urinary and fecal incontinence. Neurological examination showed a wide based gait, slurred speech, truncal ataxia, slightly saccadic ocular movement, and finger-to-nose incoordination, greater on the right than the left. Deep tendon reflexes were hyperactive and preserved with the right side greater than the left. Bilateral Babinski signs were present, and the patient had neurogenic bladder without orthostatic hypotension. Cranial MRI showed atrophy of the cerebellum with right dominance and of the pons. On T2- and PD-weighted images, high-intensity areas were detected at the left internal capsule, crus cerebri and ventral pons. These findings were compatible with the right dominance of the clinical symptoms. The high intensity area detected at the posterior internal capsule was more extensive than that seen in patients with motor neuron disease. This finding may coincide with the degenerative changes in the corticopontine tract. Moreover, 99mTc-HMPAO-SPECT showed the crossed cerebello-cerebral diaschisis (CCCD) pattern, which indicates the decreased CBF in the right cerebellar hemisphere and the left frontal lobe. These findings may reflect degenerative changes in the corticopontine tract in OPCA.

Adult↗
PubMed1995

A SP1 binding site in the GC-rich region is essential for a core promoter activity of the human endothelial nitric oxide synthase gene.

Endothelial nitric oxide synthase (eNOS) is an important oxygenase which catalyzes the conversion of L-arginine to L-citrulline to form nitric oxide (NO), a potent important factor for vasodilation and inhibition of platelet aggregation. We have analyzed characteristics of the promoter region of the human eNOS gene using the transient expression in human endothelial cells of CAT constructs with a series of 5'-deletion mutants. The 5'-flanking region between -116 and -98, which contains a putative consensus sequence for binding of transcription factor Sp1, is essential to direct a basal promoter activity. Gel mobility shift analysis involving anti-Sp1 antibody and competitor DNAs disrupted at the binding site for Sp1 reveals that Sp1 or its closely related protein(s) binds to the consensus sequence located between -104 and -96. These results indicate that the Sp1 site is essential for a core promoter activity of the human eNOS gene.

Base Composition↗
PubMed1995

Endothelin induced collagen remodeling in experimental pulmonary hypertension.

To investigate pathophysiological roles of endothelin-1 (ET-1) in collagen remodeling in pulmonary hypertension, we measured: (a) mRNA expression, concentration, localization of ET-1; (b) changes in types and content of collagen in the lung; (c) and confirmed direct effects of ET-1 on type V collagen metabolism in vascular smooth muscle cells. Monocrotaline-treated rats showed pulmonary hypertension with medial hypertrophy and perivascular fibrosis of pulmonary arteries. At the progressive stage of pulmonary hypertension, both ET-1 levels and its mRNA expression in the lung increased. Total collagen in the lung rose markedly with a higher rate of increase in type V collagen. ET-1, which exists in vascular smooth muscle cells, other perivascular cells and endothelium, stimulated type V collagen production. Our results suggest that local production of ET-1 in the lung contributes to progression of pulmonary hypertension through changes in phenotypes and content of collagen.

Animals↗
PubMed1995

Refined crystal structure of recombinant murine interferon-beta at 2.15 A resolution.

The crystal structure of recombinant murine interferon-beta (reMuIFN-beta) has been refined at 2.15 A resolution using newly collected synchrotron data. Based on 11,228 reflections (8.0 to 2.15 A), a final R-factor of 19.1% (with a free R-factor of 25.8%) was obtained with a model obeying standard geometry within 0.013 A in bond lengths and 1.4 degrees in bond angles. Compared with the previously reported model, several amino acid residues in helix A are frame-shifted, the conformations are changed for parts of loops AB and BC, helix C is extended and a new short helix exists in loop CD. Evolutionary considerations taken together, the type I interferons appear to share common structural features with respect to the chain-folding topology and the hydrogen-bond networks between various polypeptide segments. Specifically, the disposition of the C-terminal segment of loop AB (after Arg33), known to be an important receptor-binding site, seems to be strictly maintained among the type I interferons. The exposed amino acid residues on helices A and C, which have recently been implicated as the binding site for another receptor molecule, are less well conserved. This may be responsible for varied cellular effects among the subtypes of type I interferons.

Amino Acid Sequence↗
PubMed1995

Inhibitors of cGMP-dependent protein kinase block senescence induced by inactivation of T antigen in SV40-transformed immortal human fibroblasts.

Immortal human fibroblasts isolated following transfection with thermolabile simian virus 40 T antigen lost division potential upon shift up in temperature due to heat inactivation of the antigen. Such cells showed a concomitant change in the distribution of a mortality marker, mortalin, from a juxtanuclear cap like distribution of immortal cells to a uniform cytosolic distribution of mortal cells. We made an attempt to modulate the above inducible system of cellular senescence using various protein kinase inhibitors. Among the indolocarbazole type inhibitors tested, only KT5823, defined as a specific inhibitor of cGMP-dependent protein kinase, blocked the loss of division potential as determined by cell growth and colony forming ability. This inhibitor also prevented the above change in mortalin distribution due to temperature shift. In addition, the isoquinoline sulfonamide derivatives H8, H9, H88 and H89, all shown to inhibit cGMP-dependent protein kinase, suppressed the senescence. Inhibitors specific to other types of protein kinases, protein phosphatases or tyrosine kinases tested had no effect. Since there was no difference between the effective and non-effective inhibitors in their effects on cell cycle progression, cell cycle arrest by itself cannot account for the above phenomenon. These results suggest that a signaling pathway possibly mediated by cGMP-dependent protein kinase is involved in the induction of cellular senescence.

Alkaloids↗
PubMed1995

Mouse and human chromosomal assignments of mortalin, a novel member of the murine hsp70 family of proteins.

Mortalin has been shown to exhibit differential distributions in cells with mortal and immortal phenotypes. In the present study, we report mot-2 cDNA cloning from RS-4 cells--an immortal clone from CD1-ICR mouse embryonic fibroblasts--and the chromosomal assignments of mortalin related genes to mouse chromosomes 18 and X by fluorescence in situ hybridization. Similar analysis assigned the gene to chromosome 5q31.1 in human.

Animals↗
PubMed1995

Correlation between complementation group for immortality and the cellular distribution of mortalin.

The dominance of cellular senescence over the immortal phenotype has been demonstrated by cell fusion experiments utilizing human and mouse cells. Mortalin, a novel 66-kDa member of the murine hsp70 family of proteins, has recently been identified as a marker of the mortal phenotype by virtue of its characteristic cytosolic distribution in mortal cells. Here we report the mortalin immunostaining observations on 21 human cell lines. These cell lines have previously been assigned by somatic cell hybridization analysis to one (18 lines) or more than one (3 lines) of the four complementation groups (A, B, C, and D) for immortalization. Four patterns of mortalin immunostaining were observed: granular-juxtanuclear cap, granular-gradient from nuclear to cell membrane, granular-juxtanuclear arch, and fibrous-perinuclear. In 17 of 18 cell lines assigned to a single complementation group, the mortalin staining corresponded with the complementation group. In two of the three cell lines previously assigned to multiple complementation groups, the mortalin staining corresponded to one of the assigned groups. Two cell lines, however, exhibited staining patterns which did not match to their assigned complementation groups. The basis of correlation between cellular distribution of mortalin and the complementation group remains unclear at present. However, the data (i) suggest that the intracellular distribution of mortalin can be used to distinguish mortal and immortal cells, confirming the association of mortalin with senescence; (ii) provide supportive evidence for the existence of at least four different pathways of immortalization in human cells; and (iii) indicate that mortalin is involved in processes that result in immortalization.

Animals↗
PubMed1995

FGF-1 is a heparin-independent mitogen for rat hepatocytes.

We have found that in the primary culture of rat hepatocytes, the potent mitogenic activity of native FGF-1 is independent of heparin. The well-established characteristic of FGF-1 as a heparin-dependent mitogen is confirmed by human umbilical vein endothelial cells using the same preparation of FGF-1. Cross-linking experiments reveal that binding of FGF-1 to the hepatocyte cell surface receptors can be accomplished in the absence of exogenous heparin, in contrast to human endothelial cells for which it remains as a limiting factor. For both cell types, however, it is demonstrated that either endogenous or exogenous heparan sulfate/heparin moieties are essential for FGF-1 to establish receptor binding and mitogen action. Thus, the results suggest that hepatocytes harbor cell surface heparan sulfate moieties that are fully capable of utilizing FGF-1 in the environment. These results raise the possibility that FGF-1 is of differential potency for different cell types according to the nature and/or quantity of cell surface heparan sulfate moieties in vivo.

Animals↗
PubMed1995

A three-dimensional model of interferon-tau.

The interferon-tau (IFN-tau) are type I IFN whose expression is restricted to the embryonic trophectoderm of the developing placenta of ruminant ungulate species, where they act as hormones of pregnancy. Here computer modeling has been used to generate homology models of bovine and ovine IFN-tau based on the refined crystal structure of murine IFN-beta. The IFN-tau structure, like that of MuIFN-beta, is based on five long alpha helices (A-E), one short helix in the middle of the loop connecting helices C and D and a long loop between helices A and B. BoIFN-tau differs from MuIFN-beta in three important respects. First, as in all IFN-tau, there is a carboxyl tail of nine amino acids that cannot be accurately modeled but that would have a length of approximately 30 A when fully extended. Second, like the IFN-alpha subtype, all IFN-tau have a three-amino acid insertion in loop AB and a likely disulfide bridge between Cys29 and Cys139 that lead to marked conformational differences between them and MuIFN-beta in a region (Leu22 to Arg33 in IFN-tau) believed to interact with the receptor. Third, all IFN-tau, as well as the related IFN-omega, possess a Gly at position 126 (rather than the equivalent Arg on MuIFN-beta and IFN-alpha) that will impair an extensive hydrogen bonding interaction between helix D and loop AB. As a result, the polypeptide segment around this region (Phe36 to Gln40) of loop AB is likely to be considerably more flexible than in other type I IFN.

Amino Acid Sequence↗
PubMed1995

Enhancement of gamma-actin protein during liver regeneration: its accumulation in a region adjacent to the hepatocyte plasma membrane.

We identified a protein with a molecular weight of about 44 kDa in an extract of rat regenerating liver. This protein was undetectable in normal, sham-operated, and completely regenerated liver. We also purified this 44-kDa protein from an extract of rat liver remnant after partial hepatectomy. The partial amino acid sequences of the purified protein were identical to those of gamma-actin in non-muscle cells. In addition, anti-pan actin antibody recognized the purified 44-kDa protein, whereas anti-muscle actin and anti-beta-actin antibodies did not. Thus, we concluded that the 44-kDa protein was non-muscle gamma-actin. An immunohistochemical study revealed that the non-muscle gamma-actin accumulated next to the plasma membrane of liver parenchymal cells during regeneration. Moreover, the gamma-actin level was augmented in primary cultured rat hepatocytes prior to DNA synthesis. Intracellular gamma-actin in cultured hepatocytes was distributed across the entire basal plane after stimulation with hepatocyte mitogens. This change in the distribution of gamma-actin correlated with the cell spreading that occurred during the G1/S phase transition. These findings indicated that gamma-actin plays specific roles in the growth of liver parenchymal cells during liver regeneration.

Actins↗
PubMed1995

Effect of Kawasaki disease on migration of human umbilical vein endothelial cells.

Kawasaki disease, which is characterized by systemic vasculitis causing coronary arterial involvement in childhood, shows a variety of immunoregulatory abnormalities. Especially the direct or indirect deleterious effects on endothelial cells of cytokines and anti-endothelial cell antibodies (AECA) are considered to be involved in the mechanism responsible for production of vasculitis. Intravenous administration of high doses of gamma-globulin (IVGG) has been used as an effective therapy for Kawasaki disease. To examine the behavior of endothelial cells affected by cytokines and IVGG in Kawasaki disease, we studied the effects of interferon (IFN), IL-1 beta, IL-6, and tumor necrosis factor (TNF)-alpha on the migration of human umbilical vein endothelial cell line (tHUE01) by a modified Boyden chamber method. Plasma from patients with acute Kawasaki disease markedly enhanced the migration of tHUE01 cells. Cytokines, with the exception of TNF-alpha, also enhanced the migration of tHUE01 cells in a dose-dependent manner. Anti-IFN antibody inhibited the migratory activity in response to not only IFN-gamma but also to the plasma from patients with Kawasaki disease. Rabbit AECA (rAECA) also significantly stimulated the migration of tHUE01 cells. Plasma from patients treated with IVGG did not affect the migration of tHUE01 cells. Addition of gamma-globulin significantly inhibited the migration of tHUE01 cells induced by the cytokines or rAECA. These results suggest that cytokines and AECA are important in restructuring and destroying vessel walls in Kawasaki disease by enhancing the migration of endothelial cells, and that IVGG may be therapeutically effective for this disease by suppressing this endothelial cell migration.

Animals↗