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Biomedical subjects

K Nagase

Publications and source records attributed to K Nagase.

At least 55 records · Page 3Linked to original sources
PubMed1994

Metabolism of FK506, a potent immunosuppressive agent, by cytochrome P450 3A enzymes in rat, dog and human liver microsomes.

The oxidative metabolism of FK506 by liver microsomes and purified cytochrome P450 (P450) enzymes from rats, dogs and humans was studied. The major metabolite formed by liver microsomes from all species was 13-demethylated FK506, named M-I. In adult rats, liver microsomal metabolic activity toward FK506 was higher in males than in females and was stimulated by treatment with P450 3A inducers such as dexamethasone and phenobarbital. In a reconstituted monooxygenase system containing various forms of purified P450 3A enzymes, rat P450 3A2, dog P450 DPB-1 (a form of the P450 3A family) and human P450 3A4 catalyzed FK506 oxidation efficiently in the presence of cytochrome b5, a mixture of phospholipids (dilauroylphosphatidylcholine, dioleoylphosphatidylcholine and phosphatidylserine), and sodium cholate. Rat P450 2C6 and 2D1 and human P450 2CMP also metabolized FK506, with significant lower activity than the P450 3A enzymes, and other rat P450 1A, 2A, 2B, 2C and 2E families including C11 did not show catalytic activities for FK506. Anti-P450 3A2 and anti-P450 3A4 antibodies strongly inhibited FK506 oxidation catalyzed by rat and human liver microsomes, respectively. The formation rate of M-I correlated well with testosterone 2 beta- and 6 beta-hydroxylase activities in rat liver microsomes and with immunoquantified P450 3A4 content, nifedipine oxidase activity, and testosterone 6 beta-hydroxylase activity in human liver microsomes. These in vitro findings indicate that the P450 3A enzymes in liver microsomes from various species of animals, including human, play a major role in the first step oxidation of FK506.

Animals↗
PubMed1994

Distribution and protein binding of FK506, a potent immunosuppressive macrolide lactone, in human blood and its uptake by erythrocytes.

The distribution of FK506 in the blood was estimated in-vitro. At a drug level of 5 ng mL-1, FK506 mainly distributed in erythrocytes (95-98%) in dog, monkey and human blood, and its distribution was affected by drug concentration, temperature, and haematocrit values. In erythrocytes most of FK506 was distributed in cytoplasmic components and was bound strongly to a protein having a molecular weight of 10-11 kDa. The molecular weight of this protein agrees with FK506-binding protein found in various cells. Greater than 98.8% of FK506 was bound to the plasma proteins in all species studied. FK506 bound to various plasma proteins such as lipoproteins, globulins, alpha 1-acid glycoprotein and albumin.

Animals↗
PubMed1993

Effects of twenty-three drugs on the metabolism of FK506 by human liver microsomes.

We investigated the effects of 23 drugs on the metabolism of FK506 by human liver microsomes. Acyclovir, amphotericin B, cefixime, cefotaxime, ciprofloxacin, cyclosporin A, diltiazem, enoxacin, erythromycin, ethinyl estradiol, fluconazole, fosfomycin, kanamycin, lincomycin, loxoprofen, minocyclin, nifedipine, nilvadipine, norethindrone, ofloxacin, phenobarbital, prednisolone, or rifampicin was added to the reaction media at equimolar or at ten times an excess molar ratio of the substrate concentration; their effects on FK506 metabolism were examined. Drugs known to be the substrate of cytochrome P-450 3A inhibited the metabolism of FK506, and among the drugs tested, the inhibition by cyclosporin A and nifedipine was the strongest.

Anti-Infective Agents↗
PubMed1993

Perinatal development of amine, alcohol and phenol sulfoconjugations in the rat.

Development of the sulfoconjugating activities for amine, alcoholic and phenolic compounds was studied in hepatic 105,000 g supernatants of fetal and newborn rats. All activities in the fetus at the late stage of pregnancy were negligible or very low when compared with those of the adult female level. Amine and alcohol sulfoconjugating activities were low 2 days after birth, increased with age, and attained the adult female level 17 days after birth. In contrast, phenol sulfoconjugating activity was nearly half the level of adult female rats in the neonates 2 days after birth and was relatively constant before maturation. There were no sex-related differences in any of the activities in the immature rats, but in adult animals the activities for amine and alcohol were higher in the females than in the males; the opposite was observed for phenol sulfoconjugation.

Age Factors↗
PubMed1991

In-vivo processing of the initiator methionine from recombinant methionyl human interleukin-6 synthesized in Escherichia coli overproducing aminopeptidase-P.

Human interleukin 6 (hIL-6) overproduced in Escherichia coli HB101 was found to partially retain the initiator methionine (Met) residue (Met-hIL-6). In order to remove the residual N-terminal Met in vivo, an attempt was made to express hIL-6 in aminopeptidase-P (Ap-P)-hyperproducing strains, since the N-terminus Met-Pro- structure of nascent recombinant hIL-6 has been shown to be a favoured substrate of the enzyme in vitro. Using a mutant with duplicated Ap-P genes (pepP) on a chromosome or some recombinant strains overproducing Ap-P, we have succeeded in removing the initiator Met from Met-hIL-6 in vivo. The content of the mature product without the initiator Met in the pepP recombinant strains could be increased to approximately 99% from 85%.

Amino Acid Sequence↗
PubMed1991

[Preparation of monoclonal antibodies agglutinating group A, type 4 streptococci].

BALB/C mice were immunized with a partially purified M-protein fraction prepared from hot acid-extracts of a type 4, group A streptococcus, strain SS91. Two samples of monoclonal antibodies (MAb) were obtained from hybridoma cells of antibody producing spleen cells fused with NS-1 myeloma cells. Both MAb were of the subclass IgG1 having kappa-type light chains. The MAb agglutinated trypsin-digested cells of type 4 strains, but not of types 1, 2, 18, 28 and 41. This type 4-cell agglutination was inhibited by extracts of type 4 cells; strongly by hot acid-extract and partially by trypsin-extract. Hot acid-extract of type 41 cells had no inhibitory effect. Sandwich-enzyme-linked immunosorbent assay of the MAb and partially purified M-protein preparation combination against commercial T-typing sera showed that only T-type 4 antiserum reacted with the combination system. From these data, we thought that the MAb preparations were not directed to M-protein but to T-protein of type 4, group A streptococci.

Agglutination↗
PubMed1991

[STAPHYOGRAM, a new rapid identification kit for the aerobic, gram-positive, catalase-positive cocci--application of fluorometric microplate hybridization for the pre-identification of 386 isolates used].

A new simplified test kit, STAPHYOGRAM plate, was developed for 4-hr identification of aerobic, Gram-positive and catalase-positive cocci. The plate has 18 wells, in which different dehydrated substrates and nutrients are fixed. An 18-hr agar-culture suspension of a test strain with a turbidity of McFarland No. 4 was distributed into all wells in 50-microliters quantities. After 4-hr incubation at 37C, the profile number was obtained by summarizing positive reactions. The ability of the plate to differentiate the type strains of the 30 species of the three genera in the family Micrococcaceae was confirmed. These three genera are Staphylococcus, Micrococcus and Stomatococcus. The applicability of the fluorometric microplate hybridization technique to identification of aerobic, Gram-positive and catalase-positive cocci was confirmed by homologous hybridization among the type strains of the 30 species. Thus, 386 isolates of human and animal origin were pre-identified by microplate hybridization and used for evaluating the STAPHYOGRAM plate. Of the 236 profile numbers thus obtained with the 386 isolates, 218 (92.4%) were species-proper each and all for the 15 species of Staphylococcus and Stomatococcus mucilaginosus. A total of 342 (88.6%) of the 386 isolates were given such profile numbers, and were identified without any additional test. Among the 15 species identified primarily by the results of STAPHYOGRAM plate culture, S. caprae, S. lugdunensis, S. gallinarum and S. delphini were validly published after Approved Lists of Bacterial Names. The identified strains of S. caprae (48), S. haemolyticus (46), S. capitis (35) numbered between those of S. epidermidis (67) and S. saprophyticus (31). Profile numbers common to two species were seven (27 strains) and that to four species was one (17 strains). These 44 strains were identified with one to three additional tests. From these results, we were convinced that the STAPHYOGRAM test plate is useful for the rapid identification of members of family Micrococcaceae. By compiling STAPHYOGRAM plate data on genetically identified strains, an exclusive list of profile numbers will soon be prepared for perfection of the kit.

Animals↗
PubMed1991

A long-term survivor of metastatic gastric cancer treated by chemotherapy: case report.

A long-term survivor of advanced gastric cancer with multiple metastases to the liver treated by chemotherapy is described. Chemotherapy comprising a combination of uracil and tegafur with mitomycin C achieved a complete response in the patient which lasted for approximately four years. Four years after initiation of the chemotherapy, a unique form of cancer recurrence occurred on the skin, showing infiltrative erythema. Cancer metastases developed further despite more treatment, and the patient died of generalized metastasis four years six months after the initiation of chemotherapy. It is significant that, at autopsy, no cancer cells were revealed in the primary lesion or in the liver which had been present before the initial chemotherapy.

Adenocarcinoma↗
PubMed1990

High-level direct expression of semi-synthetic human interleukin-6 in Escherichia coli and production of N-terminus met-free product.

We have developed a direct expression system for high-level production of recombinant human interleukin-6 (rhIL-6) in Escherichia coli. In this system, (i) the natural N-terminal coding region of the hIL-6 gene was replaced by a synthetic sequence containing A-T rich codons, (ii) dual Shine-Dalgarno (SD) sequences were employed, (iii) an A-T rich segment was inserted in front of the initiation codon to avoid putative mRNA secondary structure in the region and (iv) the natural amber termination codon of the hIL-6 gene was changed to an ocher stop codon. The hIL-6 polypeptide, synthesized at a high level, formed cytoplasmic inclusion bodies. After refolding, the N-terminal methionine was removed by aminopeptidase-P in vitro. The purified recombinant hIL-6 had B-cell differentiation activity equivalent to natural IL-6 from a human T-cell culture.

B-Lymphocytes↗
PubMed1990

Vaccination of children in Japan.

The coverage rates of six vaccines (BCG, polio, DPT, measles, mumps and varicella) and the prevalence of these diseases in Japan were investigated. It was found that 82.2% of children had been inoculated with BCG before their first birthday, and 85.4% were given two doses of polio vaccine before their second birthday. The high acceptance rates of these vaccines seem to be attributable to mass inoculations at health centers. On the other hand, the median age when the first dose of DPT vaccine was given was as late as 22 months. Mass administration of this vaccine during infancy should be performed since about one-quarter of the patients with diphtheria, pertussis or tetanus were less than one year old. The cumulative percentage for measles inoculation failed to reach 60% by the second birthday. Considering that the incidence of measles has not yet been satisfactory lowered and that infants under 23 months of age account for about one-half of this incidence, more children less than 18 months old should be immunized. The ineffective rate of varicella vaccine was found to be 18.2%, although reestimation of its effectiveness may be necessary.

BCG Vaccine↗
PubMed1989

Two cases of hamartoangiomyomatosis with characteristic scintigraphic findings.

Hamartoangiomyomatosis is a rather rare pulmonary disease which occurs in young to middle-aged women. The chief complaint of this disease is dyspnea. The chest X-ray findings of this disease are such complicated features as reticular, reticulogranular, miliary and honeycomb-like shadow. A pulmonary perfusion scintigram was prepared with a scinticamera after intravenous injection of 10 mCi of Tc-99m MAA. The anterior image showed a remarkably reduced bilateral pulmonary blood flow, especially in the middle and lower areas of the lungs. In the upper portions, the blood flow remained relatively sufficient. The posterior and lateral images also gave similar findings. In two cases of hamartoangiomyomatosis, pulmonary perfusion scintigraphy was successful in identifying the characteristic findings of the disease.

Adult↗
PubMed1988

High-level expression of human BSF-2/IL-6 cDNA in Escherichia coli using a new type of expression-preparation system.

BSF-2 (B cell stimulatory factor-2/IL-6) is a member of the lymphokine family and responsible for B cell differentiation. Expression plasmids of human BSF-2 cDNA were constructed using a trp promotor/operator and a trpA terminator. In an extract of Escherichia coli HB101 holding "direct" expression plasmid pBSF-2D, activity of BSF-2 was detected, but overproduction was not observed. A "fused" expression system was therefore developed to prepare the recombinant protein. In this system, cDNA was expressed as a fused protein with human IL-2 N-terminal peptide. In the case of the fused BSF-2 expression plasmid, pBSF-2F, inclusion bodies were observed and overproduction of the protein occurred. As this fused protein had a Phe-Arg-Ala sequence at the junction of hIL-2 and BSF-2, it was possible to process mature BSF-2 from the fused BSF-2 by treatment with kallikrein and aminopeptidase P. From 1 liter of E. coli culture, 45 mg of mature BSF-2 was purified; it had a relative biological activity equal to that of natural BSF-2 purified from T cells.

Amino Acid Sequence↗