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Biomedical subjects

T Kozaki

Publications and source records attributed to T Kozaki.

At least 19 recordsLinked to original sources
PubMed2002

Detection of a processed pseudogene of the human MBL-associated serine protease, MASP1.

Southern hybridization analysis of the MASP1 gene using an intron-specific probe detected a single band. An exon-specific probe detected several bands. PCR of genomic DNA using several exon-specific primer sets of MASP1 produced short and long products. Sequence of the shorter products corresponded to the processed pseudogene of MASP1. By fluorescence in situ hybridization, this pseudogene (MASP1P1) was mapped to 1p34.

Amino Acid Sequence↗
PubMed2001

Syntheses and absolute stereochemistries of UPA0043 and UPA0044, cytotoxic antibiotics having a p-quinone-methide structure.

The first syntheses of new antibiotics UPA0043 and UPA0044 were accomplished starting from commercially available 18beta-glycyrrhetinic acid and vanillin. The present syntheses involve the coupling of a sesquiterpenoid aldehyde and an aryllithium, the stereoselective formation of a p-quinone-methide system, and regioselective intramolecular cyclization via an epoxy ring opening. [reaction: see text]

Antibiotics, Antineoplastic↗
PubMed2001

Apparent diffusion coefficients and chemical species of neptunium (V) in compacted Na-montmorillonite.

Diffusion of neptunium (V) in compacted Na-montmorillonite was studied through the non-steady state diffusion method. In this study, two experimental attempts were carried out to understand the diffusion mechanism of neptunium. One was to establish the diffusion activation energy, which was then used to determine the diffusion process in the montmorillonite. The other was the measurement of the distribution of neptunium in the montmorillonite by a sequential batch extraction. The apparent diffusion coefficients of neptunium in the montmorillonite at a dry density of 1.0 Mg m-3 were from 3.7 x 10(-12) m2 s-1 at 288 K to 9.2 x 10(-12) m2 s-1 at 323 K. At a dry density of 1.6 Mg m-3, the apparent diffusion coefficients ranged between 1.5 x 10(-13) m2 s-1 at 288 K and 8.7 x 10(-13) m2 s-1 at 323 K. The activation energy for the diffusion of neptunium at a dry density of 1.0 Mg m-3 was 17.5 +/- 1.9 kJ mol-1. This value is similar to those reported for diffusion of other ions in free water, e.g., 18.4 and 17.4 kJ mol-1 for Na+ and Cl-, respectively. At a dry density of 1.6 Mg.m-3, the activation energy was 39.8 +/- 1.9 kJ mol-1. The change in the activation energy suggests that the diffusion process changes depending on the dry density of the compacted montmorillonite. A characteristic distribution profile was obtained by the sequential extraction procedure for neptunium diffused in compacted montmorillonite. The estimated fraction of neptunium in the pore water was between 3% and 11% at a dry density of 1.6 Mg m-3 and at a temperature of 313 K. The major fraction of the neptunium in the montmorillonite was identified as neptunyl ions sorbed on the outer surface of the montmorillonite. These findings suggested that the activation energy for diffusion and the distribution profile of the involved nuclides could become powerful parameters in understanding the diffusion mechanism.

Bentonite↗
PubMed2001

Diffusion mechanism of chloride ions in sodium montmorillonite.

For safety assessment of geological disposal of HLW, it is necessary to understand the diffusion mechanism of radionuclides in compacted bentonite. In this study, the diffusion behavior of chloride ions in compacted montmorillonite was studied from the viewpoints of the activation energy for apparent diffusion and the basal spacing of the compacted montmorillonite. A unique change in the activation energy as a function of the dry density of the montmorillonite was found. The activation energy decreased from 17.4 to 13.5 kJ mol-1 as the dry density increased from 0.7 to 1.0 Mg m-3 and increased to 25.1 kJ mol-1 at dry densities above 1.0 Mg m-3. The basal spacing of 1.88 nm, corresponding to the three-water layer hydrate state, was not observed by X-ray diffraction (XRD) until the dry density increased to 1.0 Mg m-3, where the minimum activation energy was obtained. On the other hand, a basal spacing of 1.56 nm, corresponding to the two-water layer hydrate state, was observed at the dry densities of 1.4 Mg m-3 and above, where the activation energies were more than 22 kJ mol-1. These experimental results suggest that there are at least two additional diffusion processes that can raise or reduce the activation energy and are affected by water in the region adjacent to the montmorillonite surfaces. If the "Grahame model" can be introduced to describe the electrical double layer, surface diffusion will be considered the possible predominant diffusion process, even for anions like chloride ions.

Anions↗
PubMed2001

Fenitroxon insensitive acetylcholinesterases of the housefly, Musca domestica associated with point mutations.

The cDNA of AChE in the housefly, Musca domestica, was sequenced and individual flies were genotyped by this gene in an inhibition assay of AChE activity with an organophaspate, fenitroxon. Mutations at Gly(342) and Tyr(407), which are reportedly conserved in resistant strains of Drosophila, were associated with the insensitivity to fenitroxon. Two other mutations, Ile(162) and Val(260), did not have an apparent effect on insensitivity. However, the four mutations are located in the active site of the enzyme, and therefore the non-neutral mutations in this gene are considered to cause the insensitivity of AChE in the development of insecticide resistance of the housefly.

Acetylcholinesterase↗
PubMed1999

Characterization of cholyl-adenylate in rat liver microsomes by liquid chromatography/electrospray ionization-mass spectrometry.

The cholyl-adenylate, covalently bound 3alpha, 7alpha, 12alpha-trihydroxy-5beta-cholanoic acid (cholic acid) with adenosine 5'-monophosphate having an acid anhydride linkage, has been characterized by means of liquid chromatography/mass spectrometry in an incubation mixture with a rat liver microsomal fraction. The authentic specimen of cholyl-adenylate was synthesized using the carbodiimide method and the structure was confirmed by MS and nuclear magnetic resonance spectroscopy. After incubation of cholic acid with a hepatic microsomal fraction in the presence of adenosine 5'-triphosphate, bile acids were extracted and purified by solid-phase extraction on a Sep-Pak C18 cartridge and then subjected to a LC/MS analysis, where cholyl-adenylate and a CoA thioester of cholic acid (cholyl-CoA) were monitored with characteristic negative ions of m/z 736 and 577, respectively. Cholyl-adenylate was definitely characterized and preferential biotransformation into the acyl-adenylate prior to formation of cholyl-CoA was noted. The nonenzymatic formation of taurine-conjugated cholic acid by incubation of cholyl-adenylate with taurine in a buffer solution was also demonstrated.

Acyl Coenzyme A↗
PubMed1999

Comparative genomic hybridization defines frequent loss on 16p in human anaplastic thyroid carcinoma.

Anaplastic thyroid cancer (ATC) is one of the malignant tumors with the poor prognosis that is thought to arise from well-differentiated thyroid cancer (DTC). To investigate the molecular mechanism of ATC, we studied genomic alterations of eight ATC cell lines and three DTC cell lines by means of the comparative genomic hybridization (CGH) method. Loss of 16p was observed in five of eight ATC cell lines (62. 5%), but none of the three DTC cell lines showed loss of this chromosome arm. It is notable that loss of 18q [7/8 of ATC (87.5%), 2/3 of DTC (67%)] and gain of 20q [5/8 of ATC (62.5%), 3/3 of DTC (100%)] were frequently seen in both histologic types. Our results suggest that there is a gene in 16p that is closely associated with transformation from well-differentiated thyroid cancer to anaplastic cancer.

Carcinoma↗
PubMed1999

EM2487, a novel anti-HIV-1 antibiotic, produced by Streptomyces sp. Mer-2487: taxonomy, fermentation, biological properties, isolation and structure elucidation.

For the purpose of discovering novel agents that inhibit HIV-1 replication at the transcriptional level, we have established cell lines reflecting the HIV-1 long terminal repeat-driven gene expression. Using these cell lines, we have screened approximately 10,000 microorganism products and found that the culture supernatant of Streptomyces sp. Mer-2487 suppresses the HIV-1 Tat-induced gene expression without affecting the basal or tumor necrosis factor-alpha-induced transcription. The purified active component has a unique structure, as shown in Fig. 1. This compound has an inhibitory effect on HIV-1 replication in chronically infected cells as well as acutely infected cells, suggesting that the inhibition occurs at a postintegration step of HIV-1 proviral DNA in the HIV-1 replication cycle.

Anti-Bacterial Agents↗
PubMed1998

[Reproductive and developmental toxicity study of T-3762 in rats administered intravenously during the period of organogenesis].

A teratogenicity study of T-3762, an injectable new quinolone antibacterial agent, was conducted in Sprague-Dawley rats to determine the effects on dams and next generations. T-3762 was administered intravenously to pregnant rats at the dose levels of 26, 78 and 156 mg/kg/day from day 7 to day 17 of gestation, during the organogenesis. 1. In the dams, there were no effects on general condition, food intake, water intake and body weight in the T-3762 treated groups. There were no abnormal findings on the autopsy at the end of gestation and lactation periods in the T-3762 treated groups. 2. In the fetuses, there were no effects on the number of dead and live fetuses, sex ratio and body weight in the T-3762 treated groups. No external, visceral and skeletal abnormalities attributed to T-3762 were observed. 3. In the offspring, there were no effects on birth rate, viability, differentiation of external development, body weight, sensory function, emotionality, learning ability and reproductive performance in the T-3762 treated groups. From these results, no-toxic dose levels of T-3762 are considered to be 156 mg/kg for the general toxicity and the reproductive toxicity of parents and for the development of next generation, respectively.

Animals↗
PubMed1997

Identification of the metabolites of a new oxazolidinone MAO-A inhibitor in rat.

1. Six metabolites present in rat urine after the oral administration of E2011 ((5R)-3-[2-((1S)-3-cyano-1-hydroxypropyl)benzothiazol-6-yl]-5-meth oxymethyl-2- oxazolidinone) were isolated with an Amberlite XAD-4 column and hplc, and termed HPM-1, HPM-2, HPM-31, HPM-32, HPM-33 and HPM-4. 2. To determine the correspondence of the findings of the metabolites between tlc (which was used in our previous study) and hplc, the six metabolites were isolated from rat urine after the administration of 14C-labelled E2011 with an Amberlite XAD-4 column and hplc, and then analysed by tlc. HPM-1, HPM-2, HPM-31, HPM-32, HPM-33 and HPM-4 were identified as IM7, IM3, IM4, IM2, IM1 and E2011, respectively. 3. The structures of the metabolites were identified with nmr and mass spectrometry. One of the compounds identified, HPM-4, was the unchanged drug, E2011, and HPM-2 was O-desmethyl-E2011. Another metabolite (HPM-33), the main metabolite in the urine, was identified as (4S)-hydroxy-E2011, and the others were (4S)-hydroxy-O-desmethyl-E2011 (HPM-1), 2"-hydroxy-E2011 (HPM-31) and (4R)-hydroxy-E2011 (HPM-32). 4. In conclusion, the main metabolic pathway of E2011 in the rat consisted of O-demethylation and hydroxylation.

Animals↗
PubMed1997

Microdissection-mediated selection of chromosome region-specific cDNAs.

K562 is a cell line with two acrocentric marker chromosomes containing abnormally banded regions (ABRs), derived from a Ph-positive chronic myelogenous leukemia (CML) patient. Using reverse and forward chromosome painting FISH analysis, we found that 9q34, 13q31, and 22q11 regions co-amplified in the ABRs-bearing acrocentric marker chromosomes of K562. Utilizing the ABRs of the cell line as target DNA for cDNA selection, we established a simple procedure for chromosome region-specific cDNA isolation. After first strand cDNA synthesis from fetal brain mRNAs, short fragment cDNAs (sf-cDNAs) were synthesized with a two-step amplification system by use of our modified Degenerate Oligonucleotide Primed Shuttle Polymerase Chain Reaction (DOP-Shuttle-PCR) method. The sf-cDNAs were hybridized onto RNase A treated metaphases from K562, and the ABRs were microdissected and reamplified with DOP-Shuttle-PCR primer-II. The reamplified sf-cDNAs were cloned into a pBluescript vector. Twenty randomly chosen clones were sequenced and classified into 8 groups. Three out of the 8 grouped clones had been mapped to the long arm of chromosome 22 (22q11), whereas the other 5 were novel cDNAs. Quantitative Southern blot analysis indicated that 7 out of the 8 grouped clones (87.5%) were derived from the co-amplified regions.

Base Sequence↗
PubMed1995

[Reproductive and developmental toxicity studies of T-3761 in rats].

We carried out reproductive and developmental toxicity studies (i.e. fertility study, teratological study, and perinatal and postnatal study) of T-3761, a new quinolone derivative, in S.D. rats. T-3761 was administered orally at the dose of 60, 300 and 1,500 mg/kg/day as suspension in 5% acacia solution. 1. Fertility study T-3761 was administered to male rats for 9 weeks prior to mating and to female rats for 2 weeks prior to mating and until day 7 of gestation. In parent rats, soft stools, slight depression of body weight gain and increase in water intake were observed at the dose of 1,500 mg/kg. Cecum weight was increased at the dose of 300 mg/kg and more in male and at the dose of 1,500 mg/kg in female. No effects on reproductive performance were discernible in the T-3761 treated groups. In fetuses, external, skeletal and visceral examinations revealed no teratological abnormalities. Slightly retarded ossification, however, was observed at the dose of 1,500 mg/kg. From these findings, the no-effect dose of T-3761 in fertility study was considered to be 300 mg/kg/day for parent rats and fetuses. 2. Teratological study T-3761 was administered from day 7 to day 17 of gestation. In dams, soft stools, transient decrease in food intake, increase in water intake, depression of body weight gain and increase in cecum weight were observed at the dose of 1,500 mg/kg. In fetuses, slight increase in incidence of ventricular septal defect and slightly retarded ossification were observed at the dose of 1,500 mg/kg. In the postnatal examination, there were no effects in the T-3761 treated groups. From these findings, the no-effect dose of T-3761 in teratological study was considered to be 300 mg/kg/day for dams and next generations. 3. Perinatal and postnatal study T-3761 was administered from day 17 of gestation to day 21 of lactation. In dams, cecum weight was increased at the dose of 300 mg/kg and more. And soft stools, transient decrease in food intake, increase in water intake, transient depression of body weight gain and slight extension of gestation period were observed at the dose of 1,500 mg/kg. In the postnatal examination, there were no effects in the T-3761 treated groups. From these findings, the no-effect dose of T-3761 in perinatal and postnatal study was considered to be 300 mg/kg/day for dams and more than 1,500 mg/kg/day for next generations.

Animals↗
PubMed1994

[Chronic myelomonocytic leukemia developed 9 years after the diagnosis of idiopathic thrombocytopenic purpura in a child].

A 5-year-old girl was diagnosed as having idiopathic thrombocytopenic purpura (ITP) based on symptoms of nasal bleeding and purpura. The platelet count was 35,000/microliters without anemia or leukopenia. Micromegakaryocytes were observed in normocellular bone marrow without dyserythropoiesis or dysgranulopoiesis. She had periosteal fibroma of the rib and atopic dermatitis with elevated serum IgE. Prednisolone and azathioprine were administered but with no response. The cumulative dose of azathioprine was 20 g for 28 months. Nine years after the diagnosis of ITP, she was admitted because of dyspnea and anemia. The white cell count was 26,900/microliters with 17% monocytes. The hemoglobin was 3.9 g/dl and the platelet count was 9,000/microliters. Dyserythropoiesis, dysgranulopoiesis and micromegakaryocytes were observed in hypercellular bone marrow. The chromosome analysis demonstrated 47, XX, +21. She was diagnosed as having chronic myelomonocytic leukemia (CMMoL) and received bone marrow transplantation (BMT) from an HLA-identical sibling conditioned with high-dose busulfan and melphalan. After 17 months of remission, the disease recurred with an abnormal karyotype of 47, XX, +21, 7q+. Despite a second BMT conditioned with high-dose etoposide, cyclophosphamide and total body irradiation, she died of the disease. Refractory thrombocytopenia as a subgroup of myelodysplastic syndrome, rather than ITP, might have preceded the development of CMMoL, with the possibility of azathioprine-induced leukemia.

Adolescent↗
PubMed1991

Hypoplastic left heart syndrome with rhabdomyoma of the left ventricle.

A case of primary cardiac tumor with hypoplastic left heart syndrome (HLH) is presented. Sonographic examination at 32 weeks' gestation revealed a large tumor in the left ventricle of the fetal heart. The newborn died of congestive heart failure at 11 days of age. Autopsy demonstrated a large tumor in the left ventricle obliterating most of the left ventricular cavity, aortic atresia, and hypoplastic ascending aorta. Microscopically, the cardiac tumor showed "spider-cells" characteristics of rhabdomyoma.

Female↗
PubMed1990

Effect of solvents on the thermal isomerization of 1 alpha-hydroxyprevitamin D3 diacetate to 1 alpha-hydroxyvitamin D3 diacetate.

The thermal conversion of 1 alpha-hydroxyprevitamin D3 (1 alpha-OH-previtamin D3) diacetate to 1 alpha-hydroxyvitamin D3 (1 alpha-OH-vitamin D3) diacetate was investigated in five solvents. The fraction of 1 alpha-OH-vitamin D3 diacetate was calculated from the HPLC peak areas (UV detection) of 1 alpha-OH-previtamin D3 diacetate and 1 alpha-OH-vitamin D3 diacetate. When 1 alpha-OH-previtamin D3 diacetate was dissolved in ethanol, benzene, toluene, isopropyl ether, or n-hexane, and heated at 60 degrees C, the yield of 1 alpha-OH-vitamin D3 diacetate increased during the first 4 h, and reached an equilibrium level after 8.5 h. Differences in the ratio of 1 alpha-OH-previtamin D3 diacetate to 1 alpha-OH-vitamin D3 diacetate at thermal equilibrium, and in the rate of the thermal isomerization were observed among these five solvents. Molecular mechanics (MM) calculations were performed in order to estimate solvent effects on conformation for 1 alpha-OH-previtamin D3 diacetate and 1 alpha-OH-vitamin D3 diacetate. The solvent effect was treated by specifying a dielectric constant representative of each of the three solvents: ethanol (polar), n-hexane (nonpolar), and benzene (aromatic). The dielectric constants used were 24.3 for ethanol, 1.5 for n-hexane, and 2.3 for benzene. It is suggested that the conformation of 1 alpha-OH-vitamin D3 diacetate is stabilized in polar solvent. However, the order of conformational stability when solvent effects are included in the calculations is: ethanol greater than benzene greater than n-hexane. This order does not follow the experimental results. The proton NMR chemical shifts of 1 alpha-OH-vitamin D3 diacetate are different in deuterated n-hexane, ethanol, and benzene. The downfield shift of the C-6 vinyl proton of 1 alpha-OH-vitamin D3 diacetate, when compared to the chemical shift in benzene, is 0.15 and 0.11 ppm relative to the chemical shift in n-hexane and ethanol, respectively, and that of the C-7 proton was 0.30 and 0.33 ppm, respectively. No significant proton shift of 1 alpha-OH-previtamin D3 diacetate is recorded in these three solvents. To account for the increased ratio of 1 alpha-OH-vitamin D3 diacetate to 1 alpha-OH-previtamin D3 diacetate ratio in benzene, we suggest that 1 alpha-OH-vitamin D3 diacetate may be stabilized via specific solute-solvent interactions in benzene.

Benzene↗
PubMed1988

[Effect of position in the uterus on the fetal weight of the 21st day of pregnancy in the unilaterally ovariectomized rat].

Effects of intrauterine position of the fetuses on the weight of fetal sac, fetus and placenta were investigated on the 21th day of unilaterally (right) ovariectomized pregnant Wistar strain rats. Results were obtained as follows. 1. Litter size was negatively correlated with the mean weights of fetal sac and fetus. 2. The mean weights of male fetal sac and fetus were heavier than those of female ones, while there was no difference in the weight of placenta between male and female. 3. The mean weights of male fetal sac and fetus positioning ovarian end (OV) were lighter than those of ones at the other positions. And the highest frequency of the lightest weight of live fetuses was demonstrated at OV position. 4. The mean weights of male fetal sac and fetus positioning between two males (2M) were heavier than those of ones positioning not next to male (0M). And the mean weight of 2M female fetal sac was heavier than those of 0M one. 5. The mean weights of fetal sac and fetus positioning next to resorbed fetus were heavier than those of ones positioning not next to resorbed fetus.

Animals↗
PubMed1988

Adenosine deaminase (ADA) overproduction associated with congenital hemolytic anemia: case report and molecular analysis.

We report the fourth case of adenosine deaminase (ADA) overproduction associated with hereditary nonspherocytic hemolytic anemia and the molecular analysis of this anomaly. The proband was a 10-year-old Japanese boy, who had an episode of erythroblastosis fetalis during the perinatal period. The red cell ADA activity showed a 110-fold increase and the red cell ATP level was about 64% of the comparably reticulocyte-rich controls, but the lymphocyte ADA activity was within the normal range. Western blotting of partially purified ADA from red cells revealed an increased amount of enzyme in the patient's red cells. No gene amplification or gene rearrangement was found by Southern blot analysis, and no increase of ADA mRNA in reticulocyte RNA was detected by dot blot analysis using ADA cDNA. We constructed a genomic DNA library and obtained three clones containing the 5'-promoter region of ADA gene. The 2.2 kb ADA promoter DNA fragment of these clones was fused to the chloramphenicol acetyl transferase (CAT) gene, and transfected to human erythroid cell line K562, and assayed for CAT activity. One of the clones, pADOP 2 cat, expressed about 2.6 times higher CAT activity than the normal ADA promoter fused to CAT gene in K562, but such enhancement was not seen in human non-erythroid cell lines; HL 60 and Raji. From these results, it is most likely, though not conclusive, that the 5' promotor fragment of the ADA gene of the patient was responsible for the cell-specific enhancement of protein synthesis.

Adenosine Deaminase↗