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K Anzai

Publications and source records attributed to K Anzai.

At least 37 records · Page 2Linked to original sources
PubMed1991

Interaction with phospholipid bilayers, ion channel formation, and antimicrobial activity of basic amphipathic alpha-helical model peptides of various chain lengths.

Basic amphipathic alpha-helical peptides Ac-(Leu-Ala-Arg-Leu)3 or 4-NHCH3 (4(3) or 4(4)) and H-(Leu-Ala-Arg-Leu)3-(Leu-Arg-Ala-Leu)2 or 3-OH (4(5) or 4(6)) were synthesized and studied in terms of their interactions with phospholipid membranes, biological activity, and ion channel-forming ability. CD study of the peptides showed that they form alpha-helical structures in the presence of phospholipid liposomes and thus they have amphipathic distribution of the side chains along the axis of the helix. A leakage study of carboxyfluorescein encapsulated in phospholipid vesicles indicated that the peptides possess a highly potent ability to perturb the membrane structure. Membrane current measurements using the planar lipid bilayer technique revealed that the peptide 4(6), which was long enough to span the lipid bilayer in the alpha-helical structure, formed cation-selective ion channels at a concentration of 0.5 microM in a planar diphytanoylphosphatidylcholine bilayer. In contrast, other shorter peptides failed to form discrete and stable channels though they occasionally induced an increase in the membrane current with erratic conductance levels. The probability of detecting a conductance increase was in the order of 4(6) greater than 4(5) greater than 4(4) greater than 4(3), which corresponds to the order of the peptide chain lengths. Furthermore, 4(6) but not 4(5) showed an antimicrobial activity against both Gram-positive and -negative bacteria. The structure of ion channels formed by 4(6) and the relationship between the peptide chain length and biological activity of the synthetic peptides are discussed.

Amino Acid Sequence↗
PubMed1991

Establishment of Epstein-Barr virus-negative diffuse large cell lymphoma cell line with an 8;22 chromosomal translocation.

A new human B-cell lymphoma cell line was established from a pleural effusion of a patient with a diffuse large cell lymphoma which originated from an ileocecal tumor. The cell line, designated KAL-1, has been passaged 280 times over a period of 22 months. This cell line was successfully maintained in a chemically defined serum-free medium; its doubling time is approximately 24 h. Immunologically, the cells were demonstrated to express IgM lambda on the cell surface and to react with monoclonal antibodies to B-cell antigen including B1, B4, HLA-DR, and common acute lymphoblastic leukemic antigen but not with B2 and all the T-cell markers. Immunoglobulin gene analysis revealed rearrangements of both JH and C lambda. These data indicate that this cell line represents the B-cell lineage at the immature B-cell stage. This cell line was negative for Epstein-Barr virus nuclear antigen and had no detectable Epstein-Barr virus genome in cellular DNA. Chromosome analyses revealed that the cells carried an 8;22 chromosome translocation, reminiscent of variant type Burkitt's lymphoma. However, there was no histological evidence for Burkitt's lymphoma. Molecular studies showed that KAL-1 had deregulated high constitutive expression of c-myc. This cell line was demonstrated to be highly tumorigenic when injected into athymic nude mice. This tumor model should provide clues about the molecular mechanism involved in the pathogenesis of B-cell malignancy and appears to be a useful in vivo model for the study of molecular events during B-cell differentiation and therapeutic investigations.

Adult↗
PubMed1991

Formation of ion channels in planar lipid bilayer membranes by synthetic basic peptides.

We made use of a planar lipid bilayer system to examine the action of synthetic basic peptides which model the prepiece moiety of mitochondrial protein precursors and have antibacterial activity against Gram-positive bacteria. The sequences of the peptides used were as follows: Ac-(Ala-Arg-Leu)3-NHCH3 (3(3], Ac-(Leu-Ala-Arg-Leu)2-NHCH3 (4(2], Ac-(Leu-Ala-Arg-Leu)3-NHCH3 (4(3], Ac-(Leu-Leu-Ala-Arg-Leu)2-NHCH3 (5(2]. These peptides interacted differently with planar lipid bilayer membranes and membrane conductance increased by the formation of ion channels. The effects of the peptides on the macroscopic current-increase and on the probability of channel formation, at the single channel level were in the order of 4(3) greater than 4(2) approximately 5(2) much greater than 3(3), a finding which correlates with the antibacterial activity of these peptides. The micromolar (microM) order concentration at which the channel was formed resembles that causing antibacterial activity. Thus, the peptide antibacterial activity may occur through an increase in ion permeability of the bacterial membrane. The single-channel properties were investigated in detail using 4(3), the peptide with the highest ion channel-forming activity. Many types of channels were observed with respect to conductance (2-750 pS) and voltage dependency of gating. However, the channels were all cation-selective. These results suggest that the ion channels formed by peptide 4(3) may be able to take on a variety of conformations and/or assembly.

Amino Acid Sequence↗
PubMed1991

Brain-specific small RNA transcript of the identifier sequences is present as a 10 S ribonucleoprotein particle.

BC-1 RNA is a small RNA transcript of the identifier repetitive sequences present in rodent genomes. The RNA has been reported to be specific to the brain and confined to the cytoplasm. The RNA level increases during the 1st month after birth. To understand its cytoplasmic function, it seems important to examine whether BC-1 RNA is present as an RNP. It is believed that the protein component may govern the functions of BC-1 RNA in the brain cells. In the present report, we have demonstrated that BC-1 RNA is not free but complexed with proteins to form a 10 S RNP in the cytoplasm. We have also shown that the 10 S RNP is not associated with cytoplasmic structures such as polysomes/ribosomes or microsomes. The buoyant density of the RNP was 1.26 g/cm3 in metrizamide. Furthermore, some of the protein components were shown to be in direct contact with RNA, since photo-cross-linking adducts of protein to BC-1 RNA were identified upon UV irradiation of the 10 S BC-1 RNP.

Animals↗
PubMed1991

Elevated antibodies to synthetic peptides of HTLV-1 envelope transmembrane glycoproteins in patients with HAM/TSP.

We studied the antibody response to various kinds of well-characterized synthetic peptides of human T lymphotropic virus type 1 (HTLV-1) envelope glycoproteins in patients with HTLV-1 associated myelopathy (HAM)/tropical spastic paraparesis (TSP) and non-HAM/TSP HTLV-1 carriers. The serum antibody titers to most of the synthetic peptides were significantly higher in patients with HAM/TSP than those in non-HAM/TSP HTLV-1 carriers. However, the degree of the increase of antibody titers to the synthetic peptides corresponding to the transmembrane portions of HTLV-1 envelope glycoproteins (env-p20E), such as p20E 332-352, 374-392, 426-448 and 458-488, was greater than those to synthetic peptides of exterior portions of HTLV-1 envelope glycoproteins (env-gp46) in sera from patients with HAM/TSP. Antibodies to env-p20E 332-352 and 374-392 were elevated in the cerebrospinal fluid (CSF) only from patients with HAM/TSP but not from non-HAM/TSP HTLV-1 carriers. These data indicate that the increase of antibody titers to transmembrane portions of HTLV-1 envelope glycoproteins in sera and CSF is a characteristic feature of antibody response in patients with HAM/TSP and may be closely associated with the development of HAM/TSP from non-HAM/TSP HTLV-1 carriers.

Adult↗
PubMed1990

[Study on the clinical usefulness of NCC-ST-439 in cases of digestive tract cancer].

NCC-ST-439 is a monoclonal antibody established from human stomach cancer xenografted nude mice. The values of NCC-ST-439 were measured in 139 cases with various digestive tract cancers and 294 cases with benign digestive tract diseases with the NCC-ST-439 EIA kit (Nihon Kayaku Co., Ltd.), and its clinical usefulness was compared with those of CA19-9 and CEA. The positive rates of NCC-ST-439 in cases of digestive tract cancer were high, i.e., 66.7% for cancer of the bile duct, 58.3% for pancreatic cancer and 52.9% for colorectal cancer. In the benign digestive tract diseases, the overall positive rate seen in case of cholelithiasis and cholangitis, chronic gastritis, benign colorectal diseases and hepatitis, was only 3.7%. The positive rate of NCC-ST-439 was lower than those for CA19-9 and CEA in cases of stomach cancer, colorectal cancer and liver cancer, but it was the same as that of CA19-9 and higher than that of CEA in cases of biliary tract cancer and pancreatic cancer. The false positive rate of NCC-ST-439 in benign diseases of the digestive tract was the lowest among the three markers. With respect to sensitivity, specificity and efficiency, CA19-9 showed the highest sensitivity, but NCC-ST-439 and CEA showed better specificity than CA19-9, and NCC-ST-439 showed the highest efficiency. In combination assays using combinations of NCC-ST-439, CA19-9 and CEA, the positive rates for ST-439 alone were 22.1% for stomach cancer, 52.9% for colorectal cancer, 15.0% for liver cancer and 58.3% for pancreatic cancer, while the combined rates increased to 51.9%, 70.6%, 75.0% and 66.7%, respectively. In an investigation of changes with time in NCC-ST-439 values during chemotherapy of various types of digestive tract cancer, there was a decrease in PR cases, no change in NC cases and a tendency to increase in PD cases. These results suggested that it was possible to apply NCC-ST-439 clinically.

Aged↗
PubMed1990

Measurement of steady-state Ca2+ pump current caused by purified Ca2(+)-ATPase of sarcoplasmic reticulum incorporated into a planar bilayer lipid membrane.

The electrogenicity and some molecular properties of the sarcoplasmic reticulum Ca2+ pump protein were studied by measuring steady-state Ca2+ pump currents. Ca2(+)-ATPase protein was solubilized from rabbit skeletal muscle sarcoplasmic reticulum membrane preparations and purified by liquid chromatography. The purified Ca(+)-ATPase molecules were reconstituted into proteoliposomes and then incorporated by fusion into a planar bilayer lipid membrane. Short circuit currents across the planar membrane were detected when the ATPase molecules were activated by addition of ATP under optimal ionic conditions. Thus, the electrogenicity of the Ca2+ pump molecules was directly demonstrated. The amplitude of the pump current was dependent on the ATP concentration, and the relation was described by a Michaelis-Menten-type equation. The Michaelis constant was calculated to be 0.69 +/- 0.16 mM, which agrees well with the dissociation constant for a low affinity ATP-binding site deduced previously from the kinetics of ATP hydrolysis and from ATP binding.

Adenosine Diphosphate↗
PubMed1990

Sonographic diagnosis of venocclusive disease of the liver and danazol therapy for autoimmune thrombocytopenia in an autologous marrow transplant patient.

A 16-Year-old boy with lymphoblastic lymphoma underwent an autologous bone marrow transplantation (ABMT) after conditioning with high-dose busulfan and cyclophosphamide. On day 39 post-transplant, right upper quadrant pain occurred with an increase in the size of the liver. Liver function tests showed a subsequent deterioration. Ultrasonographic studies of the abdomen disclosed hepatosplenomegaly, ascites, thickening of the gall bladder wall and a failure to visualize the major hepatic veins. The venocclusive disease of the liver (VOD) diagnosis was confirmed from these findings. Ultrasonographic monitoring reflected the disease status well and demonstrated a complete recovery from the VOD. We emphasize, thus, that abdominal ultrasonography can be applied easily, being a non-invasive procedure, and is useful in diagnosing VOD. Furthermore, the procedure can be repeated serially for evaluating the severity of VOD. Although engraftment was confirmed with granulocytes exceeding 500/microliters, platelet recovery was delayed; the megakaryocytes had not decreased in bone marrow aspirates and platelet-associated IgG was significantly elevated. Since autoimmune thrombocytopenia was highly suspected, to prevent immunosuppression danazol was given as an immune modulator instead of prednisolone, and a complete recovery was obtained. Accordingly, danazol can be used as an alternative to prednisolone for the treatment of autoimmune thrombocytopenia after bone marrow transplantation.

Adolescent↗
PubMed1989

Regional distribution of metabotropic glutamate response in the rat brain using Xenopus oocytes.

The regional distribution of metabotropic L-glutamate responses was investigated in Xenopus oocytes injected with poly(A)+-RNA from a rat brain which was separated into 3 parts: cerebrum, cerebellum and brainstem. Under voltage-clamp, oscillatory current responses were induced more in cerebellum or brainstem poly (A)+-RNA-injected oocytes, and less in cerebrum poly(A)+-RNA-injected oocytes. These results suggest that the metabotropic glutamate receptor is distributed mostly in cerebellum and brainstem.

Animals↗
PubMed1989

[Manipulation of gallium restorative materials. 1. Control of wetting action of mixture by mulling with ethanol].

The wetting action of gallium alloy is a handicap when handling the material. Ethanol mulling after mixing was assayed in an attempt to control the wetting action of such mixtures. A mixture of gallium and Ag-Sn-Cu spherical alloy particles was mulled with a small piece of an ethanol-soaked sponge for 10 seconds following mixing by an amalgamator. The effect of this mulling on the adherence of the mixture to the capsules, physical properties and microstructures was determined. Mulling with ethanol effectively controlled the wetting action of the mixture, and reduced adherence to the capsules without affecting physical properties. A decreased reaction phase around the alloy particles was observed in the microstructure of the ethanol-mulled specimen.

Dental Alloys↗
PubMed1988

ID sequence-binding protein factor complexed in ribonucleoprotein particles.

We analyzed brain extracts from fetal or adult mice with a 32P-labeled 5'-half fragment of identifier (ID) sequence in a gel mobility shift assay. Upon digestion of extracts with RNase A prior to the binding reactions, a protein factor(s) that specifically binds to the fragment was shown to appreciably increase in amount with either of the extracts. Furthermore, the binding was competed with single-stranded ID sequences. These observations suggest that the protein factor is capable of interacting with either the genes or their small RNA transcripts.

Animals↗
PubMed1988

Rapid determination of internal volumes of membrane vesicles with electron spin resonance-stopped flow technique.

We have developed an electron spin resonance (ESR)-stopped flow technique and employed it for the simple and rapid determination of internal volumes of biomembrane vesicles and liposomes. A vesicle suspension containing a neutral and membrane-permeable spin label, 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl (TEMPONE), was mixed in the stopped-flow apparatus with an isotonic solution of relatively impermeable line broadening agents, potassium tris(oxalato)chromate(III) or potassium ferricyanide, and an ESR spectrum was recorded. From the relative intensity of the sharp triplet signal due to TEMPONE in the aqueous space within vesicles, the determination of the internal aqueous volume was straightforward. Using this technique, it is possible to measure intravesicular volumes in 0.1 s. The internal volume of sonicated phospholipid vesicles was approximately 0.3 microliter/mg lipid. The light fraction of sarcoplasmic reticulum membrane vesicles isolated from rabbit skeletal muscle was estimated to have an internal volume of 2.2-2.6 microliter/mg protein in its resting state. Activation of Ca2+ pumps in the membrane upon addition of ATP and Ca2+ ions decreased the internal volume by about 10%. This finding supports the hypothesis that the Ca2+ pump is electrogenic and that the efflux of potassium ions compensates for the influx of positive charges. The present technique is widely applicable to the simple and rapid determination of the internal volumes of membrane vesicles.

Animals↗
PubMed1988

Taurine and beta-alanine act on both GABA and glycine receptors in Xenopus oocyte injected with mouse brain messenger RNA.

The responding pathway (process from agonist binding to channel opening) of taurine and beta-alanine was investigated in Xenopus oocytes injected with mouse brain poly(A)+ RNA. Responses to gamma-aminobutyric acid (GABA), glycine, taurine and beta-alanine were induced in oocytes injected with poly(A)+ RNA extracted from 3 regions, cerebrum, cerebellum and brainstem of the mouse brain. From comparison, responses to these 4 inhibitory amino acids in each regional poly(A)+ RNA-injected oocytes were categorized into at least 3 groups: (1) GABA, (2) glycine, and (3) taurine and beta-alanine. No cross-desensitization was observed between GABA response and glycine response, but taurine and beta-alanine responses cross-desensitized both the GABA and glycine responses. Taurine and beta-alanine responses were partially inhibited by the GABA antagonist, bicuculline, and also by the glycine antagonist, strychnine. The results suggest that the taurine or the beta-alanine response in the brain is caused through both the GABA receptor and the glycine receptor.

Alanine↗
PubMed1988

ID sequence-binding protein factors during development of mice.

The ID repetitive sequence has been reported to be transcribed as small RNA in both a brain-specific and a developmental stage-specific manner. Several brain-specific proteins required for transcription, along with RNA polymerase III, may be involved in controlling the gene activity throughout development. We analyzed extracts from the brains and livers of mice in an electrophoretic mobility shift assay. Of ID sequence-binding proteins, we detected a protein factor(s) that interacts specifically with the region between two promoter sequences for RNA polymerase III. This protein factor seems to be relevant to postnatal accumulation of the small RNA transcripts of ID sequences, since its time course of expression is consistent with that of the synthesis of the small RNA during development. A penta-nucleotide direct repeat (GCAAG) and its inverted complement (CTTGC) are both present in that region and may be involved in the binding site for the protein factor. The biological significance of the binding site and interacting protein factor(s) is discussed.

Aging↗
PubMed1988

Cation channels from ciliary membrane of Tetrahymena reconstituted into planar lipid bilayer. Comparison between the channels from the wild T. thermophila and from its mutant which does not show ciliary reversal.

Cation channels in ciliary membrane vesicles from wild type Tetrahymena thermophila and from its mutant which does not show ciliary reversal or avoiding reaction were reconstituted into a planar lipid bilayer. Since the mutant does not produce the regenerative Ca2+ action potential, the mutation was expected to have occurred at the Ca-channel in the ciliary membrane. In the sample from the mutant, the channel most frequently observed was selective for cations over anions. The single channel conductance shows Michaelis-Menten type dependency on the cation concentration. The maximum conductance and dissociation constants (in parenthesis) for K+, Mg2+, Ca2+, and Ba2+ were 371 pS (23.3 mM), 17 pS (0.49 mM), 18 pS (0.52 mM), and 25 pS (0.82 mM), respectively, when the anion was gluconate. The properties of the corresponding channel from the wild type are similar to those from the mutant. No essential difference was detected, which indicates that the predominant channel is not the putative Ca channel responsible for the avoiding reaction of Tetrahymena. Some other channels than the predominant channel were also observed.

Animals↗