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Biomedical subjects

J Suzuki

Publications and source records attributed to J Suzuki.

At least 271 records · Page 15Linked to original sources

Development of protamine-bonded phase for separation of saccharides in liquid chromatography.

A protamine-bonded polymer gel was synthesized by passing this protein through an activated carbamate polyamine polymer gel layer. This new packing material was suitable for versatile separation of monosaccharides, oligosaccharides, sugar alcohols and uronic acids in liquid chromatography. The column packed with this gel could be operated at room temperature and gave excellent recovery for the reducing monosaccharides such as 2-deoxyribose, 2-deoxyglucose, ribose and mannose for which the conventional alkylamine-bonded phase column gave poor recovery. This column was used for the analysis of saccharides in urine using a post-column reaction detection system.

Amino Acid Sequence↗

Very low density lipoprotein receptor binds apolipoprotein E2/2 as well as apolipoprotein E3/3.

The VLDL receptor, a newly identified lipoprotein receptor, recognizes apoE containing lipoproteins. The human VLDL receptor was overexpressed in 1d1A-7, a mutant Chinese hamster ovary cells lacking LDL receptors. Each VLDL obtained from a normolipidemic subject with two epsilon3 or epsilon2 alleles similarly competed for the binding of radiolabeled rabbit beta-VLDL to the VLDL receptors. The anti-apoE monoclonal antibody 1D7, which inhibited binding of apoE3 to the LDL receptors, failed to compete for the binding of VLDL (apoE3 or apoE2) to the VLDL receptors. Results indicate that the binding site of apoE on the VLDL receptor may differ from its binding site on the LDL receptor.

Animals↗

Difference between normal and WHHL rabbits in susceptibility to the adrenal toxicity of an acyl-CoA:cholesterol acyltransferase inhibitor, FR145237.

The adrenal toxicity of an acyl-CoA:cholesterol acyltransferase (ACAT) inhibitor, FR145237, was investigated using Japanese White (normal) and low density lipoprotein (LDL) receptor deficient Watanabe heritable hyperlipidemic (WHHL) rabbits. In the normal rabbits, severe necrosis of the cells in the zona fasciculata and reticularis was observed 24 hr after intravenous injection of 3.2 mg/kg of FR145237, whereas no morphological changes could be found in the adrenal cells of the WHHL rabbits in spite of a higher plasma concentration of the drug. Since most of the FR145237 (87%) in the plasma of the WHHL rabbits was recovered in the LDL fraction 1 hr after intravenous injection of the drug (3.2 mg/kg), it was hypothesized that the delivery of the drug to the adrenal cells may be limited by the LDL receptor deficiency. However, the concentration of FR145237 in the adrenal gland of the WHHL rabbits (13.3 microg/g) was identical to that in the normal rabbits (13.6 microg/g). These results suggest that the susceptibility of the adrenal cells of the WHHL rabbits to the toxicity of FR145237 truly differs from that of normal rabbits, and that the WHHL rabbit may be a useful animal model for the investigation of the mechanisms of the adrenal toxicity of ACAT inhibitors.

Adrenal Cortex↗

The role of cell adhesion molecules in allograft rejection after penetrating keratoplasty in mice. Clinical and immunohistochemical study.

BACKGROUND: It has been reported that adhesion molecules play an important role in immunological rejection after organ transplantation. In the present study, we examined the role of ICAM-1/ LFA-1 adhesion molecules in corneal allograft rejection and evaluated the immunological specificity of monoclonal antibodies (mAbs) in preventing allograft rejection in mice. METHODS: The allografted mice were intraperitoneally injected with 100 micrograms/day of the following mAbs: a control mAb, anti-ICAM-1 mAb, anti-LFA-1 mAb, or a mixture of anti-ICAM-1 and anti-LFA-1 mAbs from 1 day before to 7 days after surgery. The expression of ICAM-1 and LFA-1 molecules in the grafted cornea was studied immunohistochemically. The corneas from a syngeneic donor or a third-party strain were transplanted 4 weeks after the initial keratoplasty onto the mice treated with both anti-ICAM-1 and anti-LFA-1 mAbs. RESULTS: The allografts treated with anti-LFA-1 mAb alone or both anti-ICAM-1 and anti-LFA-1 mAbs remained transparent for more than 2 weeks, and the survival rate at 8 weeks was 40% in both groups. ICAM-1 was expressed on the mononuclear cells, keratocytes and endothelial cells in the allografts without treatment. The second corneal grafts syngeneic to the initial donor remained transparent at 2 weeks, whereas those from the third party were rejected. CONCLUSIONS: ICAM-1 and LFA-1 adhesion molecules play a crucial role in the pathophysiology of corneal transplant rejection. The immunosuppressive effects of anti-ICAM-1 and anti-LFA-1 mAbs are highly allospecific. The administration of mAbs to the adhesion molecules represents a new means of suppressing allograft rejection after penetrating keratoplasty.

Animals↗

Molecular analysis of ocular adnexal lymphoid proliferations. Characteristics of immunoglobulin VH, D and J segment usage.

We investigated the molecular characteristics of six cases of ocular adnexal lymphoid proliferation. Although their clinical diagnoses varied, all of them were diagnosed as having malignant lymphomas by immunohistochemical examinations and molecular approaches. Proliferating cells showed the B cell phenotype, positive for L26/CD20 and negative for UCHL1/CD45RO, and genotypic study by Southern blotting revealed that all cases had gene rearrangements of the immunoglobulin heavy chain with or without those of the kappa (kappa) light chain. Epstein-Barr virus infection was not identified. Usage of variable domains of the immunoglobulin heavy chain was analyzed. Subgroup 3 of the VH gene was present relatively often, in 3 of 6 cases, perhaps due to its having the largest number of VH gene segments. On the other hand, an unexpectedly high frequency of the DLR family of the D gene segment was observed by sequencing the third complementarity determining region. These molecular characteristics in ocular adnexal lymphoid neoplasms might be related to the clinical course.

Adult↗

Developmental and seizure-related regional differences in immediate early gene expression and GABAergic abnormalities in the brain of EL mice.

To examine the hypothesized role of the immediate early gene (IEG) response in synaptic plasticity and in epileptogenesis, we studied the spatial specificity of the expression of IEG in EL mice, a well known mutant model of epilepsy. Also to examine the 'GABA hypothesis' in epilepsy, GABA concentration and GAD activity was determined in micro brain regions (10-300 ng) of EL mice related to the focus in the parietal cortex and the hippocampus. We found that the IEG expression after seizures is not related to the seizure pattern, but to the seizure history, seizure threshold and development of EL[s]. Even in the interictal period, EL mice with long seizure histories and very low seizure thresholds demonstrate IEG expression continuously. This is probably strengthened by repeated seizures. The IEG expression site is however located in the hippocampal CA1, which is the final terminal of various inputs from other areas of the limbic system. It is proposed that the continuous expression of IEGs might play a different role from that of transiently expressed IEGs. Developmentally, the site of IEG expression shifted from one site to another in a very similar manner as in the IEG expression with propagation of paroxysmal discharges in each seizure, and the three-dimensional expression area was gradually expanded, suggesting a change in the regional active site during epileptogenesis. These lines of evidence suggest that during development as well as repetitive seizures, frequent expressions of IEGs and syntheses of Fos and Zif proteins might facilitate synaptic conductivity involved in epileptogenesis. The sites of abnormal GABA concentrations and GAD activities were almost the same in the parietal cortex, around Sidman atlas coronal section No. 300 and in the hippocampal CA1 pyramidal cells as the spatio-temporal specific IEG expression sites. These findings strongly suggest that IEG expression and abnormal GABAergic functions are involved in epileptogenesis in EL mice.

Animals↗

Nonenzymatic sequence-specific cleavage of duplex DNA via triple-helix formation by homopyrimidine phosphorothioate oligonucleotides.

Phenanthroline was attached covalently to the 5'-terminus of the unmodified and modified (3'-terminal phosphorothioate) oligonucleotide sequences, TTTTTTCTTCTCTTTCC (OP-17 mer) and TTTTTTTCTTCTCTTTCsC (OPRp-17 mer or OPSp-17 mer) via a phosphoramidite bond. Simian virus 40 DNA contains a single target site for these oligonucleotides. In the presence of copper ions, the efficient double-stranded cleavage at 37 degrees C and pH 7.0 was observed by agarose gel electrophoresis. The asymmetric distribution of the cleavage sites on the two strands revealed that the cleavage reaction took place in the minor groove, even though the linker was located in the major groove. Of particular interest are the 3'-terminal phosphorothioate oligonucleotide-phenanthroline derivatives (Rp or Sp), which were found to have cleavage activities of the same order as for the oligonucleotide phenanthroline (OP-17 mer). Furthermore, the OPSp-17 mer was intact after incubation in 10% fetal bovine serum for 24 h, whereas, the OPRp-17 mer was slightly more unstable than the OPSp-17 mer. However, the OP-17 mer was completely degraded. An increased resistance to nucleases has been observed by the introduction of phosphorothioate groups on the 3'-terminus of oligonucleotide-phenanthroline derivatives. This stabilization should help us to design much more efficient chemical recognition enzymes and antisense nucleic acid based anti-viral therapies, which could be used as tools in cellular biology.

Animals↗

The association of antibodies against human T cell lymphotropic virus type I (HTLV-I) pX gene mutant products with HTLV-I-associated myelopathy/tropical spastic paraparesis.

Antibodies specific for the products of the human T cell lymphotropic virus type I (HTLV-I) pX frame-shift mutants were studied by ELISA. The serum IgG antibodies to the synthetic peptide corresponding to one nucleotide insertion at position 7784 were significantly more common in patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients than in HTLV-I carriers who had neither HAM/TSP nor adult T cell leukemia (39% vs. 5%). The seropositivities to the other synthetic peptides, which corresponded to the one nucleotide deletion at position 7475 and the internal deletion of nt 7754-7819 and nt 7853-7936, were rare. A genetic study confirmed the presence of the responsible mutation of the pX gene in peripheral blood mononuclear cells and central nervous system tissue from HTLV-I-infected subjects with and without HAM/TSP. These results suggest that HTLV-I pX frame-shift mutants are expressed in vivo in HTLV-I carriers; they also induce antibodies. especially in those with HAM/TSP.

Adult↗

Role of calcium in tumor necrosis factor-alpha production by activated macrophages.

The role of calcium in the production of tumor necrosis factor-alpha (TNF-alpha) by the lipopolysaccharide (LPS)-stimulated macrophage cell line, J774.1, was investigated. Flow cytometric measurement of intracellular calcium concentration ([Ca]i) using 2-(3,6-bis(acetyl-oxy)-2,7-dichloro-9H-xanthen-9-yl)benzoic acid (fluo-3)-loaded J774.1 cells revealed that LPS at more than 0.1 microgram/ml increased [Ca]i transiently in the presence or absence of serum, and that a mixture of a calcium chelator, ethyleneglycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA), and a calcium release blocker from intracellular store sites, 8-(diethylamino)-octyl-3,4,5-trimethoxybenzoate hydrochloride (TMB-8), inhibited the [Ca]i response induced by LPS. In concordance with this, production of TNF-alpha was inhibited by EGTA and/or TMB-8. These reagents also reduced the level of TNF-alpha mRNA significantly. These results indicate that the transient increase of [Ca]i plays a role in LPS-induced expression of TNF-alpha by the macrophage cell line.

Animals↗

Different sensitivity to streptolysin-O of cells in macrophage lineage.

We have surveyed the sensitivity of cells in macrophage lineage to Streptolysin-O (SLO). SLO had cytotoxic activity on immature myeloid cell lines such as M1 and WEHI-3BD+. SLO was toxic to the cells after a 2-hr incubation. However, mature macrophage cell lines such as A640-BB-2, J774, and P388D1 were not sensitive to the same dose of SLO. After M1 cells were treated with leukemia inhibitory factor (LIF), a differentiation-inducer to macrophage, these cells became insensitive to SLO in one day. This cytotoxic action of SLO was inhibited by pretreatment with anti-Streptolysin-O antibody or cholesterol. These results indicate that SLO has different effects on macrophage lineage.

Antibodies, Blocking↗

Sjögren's syndrome with membranous glomerulonephritis detected by urine screening of schoolchildren.

A case of Sjögren's syndrome with glomerulonephritis is presented. The patient was a 13 year old male with hematuria and proteinuria discovered by urine screening of school children. Evaluation showed no evidence of any associated connective tissue disease. Kidney biopsy was consistent with membranous glomerulonephritis. Sjögren's syndrome with membranous glomerulonephritis is rare and the patient was the youngest case in the literature.

Adolescent↗

[Properties of a hemolysin produced by group B streptococci].

The hemolysin produced by group B streptococci (GBH) has an isoelectric point (pI) of 5.8 and it shows a hemolytic activity in the absence of 2-mercaptoethanol (2-ME). The hemolytic activities of GBH were compared to that of streptolysin O (SLO) and streptolysin S (SLS). These hemolysins differed with respect to the binding and release of hemoglobin (Hb). GBH was bound to phospholipids on the membranes of target erythrocytes, followed by the gentle release of K+ and slow Hb release without lag time. Incontrast SLO released Hb as rapidly as K+. GBH induced hemolysis was inhibited by the addition of 30 mM raffinose. These results indicate that the effective diameter of the pores formed by GBH was about 1.1 nm. GBH showed a lower hemolytic efficiency than SLO, reflecting the fact that these hemolysins destroy erythrocytes by a different mechanism. Intracellular K+ and Hb were released at a different rate in GBH treated cells, indicating that a colloid-osmotic process is involved in the lytic mechanism.

Bacterial Proteins↗

[A case of Tsutsugamushi disease infected by mountain climbing in the Republic of Korea].

A 47-year-old male was infected with Tsutsugamushi disease showing typical findings after mountain climbing in the Republic of Korea (ROK). Immunoserological examinations suggested that he had been infected in ROK. In this case, detection of the characteristic sting was useful for early diagnosis and treatment. Until now, Tsusugamushi disease has not been reported in Hokkaido. It is the first case registered in Hokkaido. With extensive international intercourse these days, this case suggests that Tsutsugamushi disease can occur potentially all over Japan.

Humans↗

Characterization of manganese peroxidases from the hyperlignolytic fungus IZU-154.

Four isozymes of manganese peroxidase (MnP) were identified in the culture fluid of the hyperlignolytic fungus IZU-154 under nitrogen starvation conditions. One of them was purified and characterized kinetically. The specific activity and Kcat/K(m) value of the MnP from IZU-154 were 1.6 times higher than those of the MnP from a typical lignin-degrading fungus, Phanerochaete chrysosporium. Two cDNAs encoding MnP isozymes from IZU-154 were isolated. The coding sequence of the two cDNAs, IZ-MnP1 cDNA and IZ-MnP2 cDNA, were 1,152 (384 amino acids) and 1,155 (385 amino acids) bp in length, respectively. They exhibit 96.2% identity at the nucleotide level and 95.1% identity at the amino acid level. Southern blot analysis indicated that two MnP isozyme genes exist in IZU-154 genomic DNA. The primary structures of two MnPs from IZU-154 were similar to those of MnPs from P. chrysosporium. The amino acid sequences including the important residues identified in MnPs from P. chrysosporium, such as the manganese-binding residues, the calcium-binding residues, the disulfide bonds, and the N-glycosylation site, were conserved in the two deduced IZ-MnPs. However, several discrepancies were found in the context around the distal histidine residue between MnP from IZU-154 and MnP from P. chrysosporium, which likely led to the difference in the kinetic parameters for MnP function.

Amino Acid Sequence↗

Effects of fenoterol on inspiratory effort sensation and fatigue during inspiratory threshold loading.

We studied the effects of a single dose of fenoterol on the relationship between inspiratory effort sensation (IES) and inspiratory muscle fatigue induced by inspiratory threshold loading in healthy subjects. The magnitude of the threshold was 60% of maximal static inspiratory mouth pressure (PI,mmax) at functional residual capacity, and the duty cycle was 0.5. Subjects continued the threshold loaded breathing until the target mouth pressure could no longer be maintained (endurance time). The intensity of the IES was scored with a modified Borg scale. Either fenoterol (5 mg) or a placebo was given orally 2 h before loading in a randomized double-blind crossover protocol. The endurance time with fenoterol (34.4 +/- 8.6 min) was longer than that with the placebo (22.2 +/- 7.1 min; P < 0.05). The ratio of high- to low-frequency power of the diaphragmatic electromyogram (EMGdi) decreased during loading; the decrease was less with fenoterol (P < 0.05). The EMGdi also decreased with loading; the decrease was greater on fenoterol treatment (P < 0.01). The PI,mmax and maximal transdiaphragmatic pressure (Pdi) were similarly decreased after loading on either treatment. The intensity of the IES rose with time during loading in both groups but was lower with fenoterol than with the placebo (P < 0.05). The ratio of Pdi to integrated activity of the EMGdi increased with fenoterol (P < 0.05). Fenoterol treatment increased both superimposed Pdi twitch and Pdi twitch of relaxed diaphragm and decreased the value of (1-superimposed Pdi twitch/Pdi twitch of relaxed diaphragm). Thus we conclude that in normal subjects fenoterol reduces diaphragmatic fatigue and decreases the motor command to the diaphragm, resulting in a decrease in IES during inspiratory threshold loading and a prolongation of endurance.

Adult↗

Adaptation of primate vestibuloocular reflex to altered peripheral vestibular inputs. I. Frequency-specific recovery of horizontal VOR after inactivation of the lateral semicircular canals.

1. The adaptive plasticity of the vestibuloocular reflex (VOR) following a selective lesion of the peripheral vestibular organs was investigated in rhesus monkeys whose lateral semicircular canals were inactivated by plugging of the canal lumen in both ears. Gain and phase of horizontal, vertical, and torsional slow-phase eye velocity were determined from three-dimensional eye movement recordings obtained acutely after the plugging operation, as well as in regular intervals up to 10 mo later. 2. Acutely after plugging, horizontal VOR was minimal during yaw rotation with gains of < 0.1 at all frequencies. Horizontal VOR gain gradually increased over time, reaching gains of 0.4-0.5 for yaw oscillations at 1.1 Hz approximately 5 mo after lateral canal inactivation. This response recovery was strongly frequency dependent: horizontal VOR gains were largest at the highest frequency tested and progressively decreased for lower frequencies. Below approximately 0.1 Hz, no consistent horizontal VOR could be elicited even 10 mo after plugging. 3. The frequency-dependent changes in gain paralleled changes in horizontal VOR phase. Below approximately 0.1-0.05 Hz large phase leads were present, similarly as in semicircular canal primary afferents. Smaller phase leads were also present at higher frequencies, particularly at 1.1 Hz (the highest frequency tested). 4. Consistent with the afferent-like dynamics of the adapted horizontal VOR, per- and postrotatory horizontal responses to constant-velocity yaw rotations were short lasting. Time constants of the slow-phase eye velocity envelope of the horizontal postrotatory nystagmus were approximately 2 s. Nonetheless, a consistent horizontal optokinetic afternystagmus was evoked in plugged animals. 5. A torsional component that was absent in intact animals was consistently present during yaw rotation acutely after lateral canal inactivation and remained approximately constant thereafter. The frequency response characteristics of this torsional component resembled those of the adapted horizontal slow-phase responses: gain decreased and large phase leads were introduced at frequencies below approximately 0.05-0.1 Hz. Torsional responses elicited by roll oscillations in supine position, on the other hand, were indistinguishable in their dynamics from intact animals. No consistent vertical nystagmus was elicited during yaw rotation. 6. Our results show that there is a slow, frequency-specific recovery of horizontal VOR after selective inactivation of the lateral semicircular canals. Both the spatial organization and the dynamic properties of the adapted VOR responses are distinctly different from responses in intact animals, suggesting complex changes in the underlying vestibuloocular circuitry.

Adaptation, Physiological↗