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Biomedical subjects

S Fujii

Publications and source records attributed to S Fujii.

At least 973 records · Page 54Linked to original sources
PubMed1977

Effects of gastrointestinal and related hormones on glycogenolysis and gluconeogenesis in cultured liver cells.

When isolated rat liver cells were incubated for 15 min in the presence of vasoactive intestinal peptide, secretin, gastrin, caerulein or glucagon at concentrations ranging from 0.2 microgram to 2 microgram per ml, glycogenolysis was stimulated. Among the gastrointestinal hormones or peptides tested, vasoactive intestinal peptide had the highest stimulatory activity. However, somatostatin was inhibitory for liver glycogenolysis. Combination experiments showed that somatostatin also inhibited the stimulatory effects of vasoactive intestinal peptide and secretin, but not that of glucagon, while glucagon and vasoactive intestinal peptide, or glucagon and secretin showed additive effects on glycogenolysis, but secretin and vasoactive intestinal peptide did not. The results suffest that the receptor site of glucagon is different from those of secretin and vasoactive intestinal peptide. Slight but significant stimulation of gluconeogenesis was also observed by vasoactive intestinal peptide and secretin. The evidence presented in this paper indicates that the so-called enterohepatic axis, in which a part of serum glucose levels is regulated directly by gastrointestinal hormones, exists and that the axis is inhibited by somatostatin.

Animals↗
PubMed1977

Characterization of pyrimidine nucleoside monophosphokinase in normal and malignant tissues.

It was found that there are two kinds of pyrimidine nucleoside, monophosphokinase deoxythymidine 5'-monophosphate-deoxyuridine 5'-monophosphate (dTMP-dUMP) kinase and cytidine 5'-monophosphate-deoxycytidine 5'-monophosphate-uridine 5'-monophosphate-doexyuridine 5'-monophosphate (CMP-dCMP-UMP-dUMP) kinase, and their molecular weights were calculated to be 46,000 and 26,000, respectively, by gel filtration. dTMP-dUMP kinase phosphorylated dTMP with a Km of 3.1 X 10(-5)M and dUMP with a Km of 7.7 X 10(-4) M. dTMP phosphorylation catalyzed by dTMP-dUMP kinase was inhibited competively by dUMP with a Ki of 2.0 X 10(-3) M. Similarly, phosphorylation of dUMP by this enzyme was inhibited competively by dTMP with a Ki of 2.5 X 10 (-5) M. CMP-dCMP-UMP-dUMP kinase of Yoshida sarcoma phosphorylated dUMP with a Km of 3.1 X 10(-3) M and dCMP with a Km of 7.1 X 10 (-4) M, but it did not phosphorylate dTMP. Phosphorylation of dUMP BY CMP-dCMP-UMP-dUMP kinase was inhibited competitively by DCMP and dTMP with Ki's of 6.9 X 10(-4) and 3.0 X 10(-3) M, respectively, and phosphorylation of dCMP was inhibited completely by dUMP a Ki of 2.2 X 10(-3) M. Relative Vmax activity of this enzyme was 345 nmoles/mg protein with dCMP and 127 nmoles/mg protein with dUMP.

Animals↗
PubMed1977

Comparative studies on the metabolism of 2-(tetrahydrofuryl)-5-fluorouracil and 5-fluorouracil.

5=Fluorouracil inhibited DNA synthesis markedly using various DNA precursors such as deoxyuridine, orotic acid, uracil, and uridine except for thymidine. 2-(Tetrahydrofury)-5-fluorouracil (FT-207) did not inhibit DNA synthesis with any of the precursors tested. The metabolisms of 5-fluorouracil and FT-207 in mice and rats were studied. When administered intravenously 5-fluorouracil was rapidly degraded to fluoro-beta-alanine in both mice and rats, while at most 70% of FT-207 was slowly degraded after a prolonged period. The metabolites of FT-207 were found to be 5-fluorouracil and fluoro-beta-alanine in both species of animals. In vitro degradation of FT-207 into 5-fluorouracil was observed mainly in the microsomal fraction in the presence of NADPH. This result suggested that microsomal electron-transport system was concerned with the degradation of FT-207.

Alanine↗
PubMed1977

A new deoxyuridine-5'-triphosphatase in Yoshida sarcoma cells involved in deoxyuridine 5'-triphosphate metabolism.

A magnesium-independent deoxyuridine-5'-triphosphatase was found in Yoshida sarcoma cells but not in normal rat liver. The phosphatase is specific for deoxyuridine 5'-diphosphate and deoxyuridine triphosphate, and its Km for deoxyuridine triphosphate is 2.7 X 10(-7) M. The enzyme was not inhibited by fluoride and required no divalent cations. Thus it differs from known nucleotide phosphatases. Deoxyuridine monophosphokinase, which is detectable in a crude extract of normal rat liver, could not be detected in an extract of Yoshida sarcoma cells. However, with hydroxylapatite column chromatography of the extract, a deoxyuridine 5'-monophosphate kinase activity as high as that in normal rat liver was found in fractions separated from the phosphatase activity. Thus the absence of detectable deoxyuridine 5'-monophosphate kinase activity in the crude extract of Yoshida sarcoma cells is due to the presence of this nucleotide phosphatase.

Animals↗
PubMed1977

Effect of thymidine and thymidylate analogs on nucleic acid synthesis in tumor cells.

Synthetic 5'-amino-5'-deoxythymidine (5'-AdThd), alpha,beta-methylenethymidine diphosphate (alpha,beta-MTDP), and alpha,beta-methylenethimidine triphosphate (alpha,beta-MTTP) were found to inhibit thymidine kinase. Using thymidine kinase extracted from FM 3A/B cells (a strain of mouse mammary gland tumor cells), the Ki values of 5'-AdThd, alpha,beta-MTDP, and alpha,beta-MTTP against thymidine were calculated to be 9.2 X 10(-5)M, 2.3 X 10(-5) M, and 1.8 X 10(-5) M, respectively. At concentrations above their Ki values alpha,beta-MTDP and alpha,beta-MTTP did not inhibit incorporation of labeled thymidine into DNA of cultured cells, whereas 5'-AdThd did. Under the same conditions all three compounds inhibited TMP incorporation. The inhibitions of thymidine and TMP incorporation were specific, since the incorporation of deoxyguanosine was scarcely inhibired by 5'-AdThd. These results suggested that the specific inhibition of thymidine and TMP incorporation was mostly due to reduction in permeability of the cells to these substrates rather than to inhibition of thymidine kinase activity.

Animals↗
PubMed1977

[A study on midecamycin granules in acute respiratory diseases in infants (author's transl)].

We have undertaken some basic and clinical studies on midecamycin granules with following results: 1) After ingesting of 4 g of midecamycin granules, peak blood levels (1.51 microgram/ml on an average) appeared at one hour in infants, detectable amount lasting for 6 hours. 2) Urinary excretion within 6 hours ranged from 1.1 to 2.7% of the drug dosed. 3) In the treatment of a total of 19 acute cases, consisting of 9 cases of tonsillitis, 7 cases of lacunar tonsillitis and 3 cases of bronchitis, midecamycin was found effective in 79% of the cases. 4) In all the 3 cases of pneumonia due to Mycoplasma, response to midecamycin was assessed as excellent. 5) Hepatic and renal functions tests performed in cases treated with the drug for a prolonged period (40 approximately 50 mg/kg for 13 approximately 18 days) revealed no undesirable effect, indicating that midecamycin can be administered continuously to younger infants with infections.

Acute Disease↗
PubMed1976

Conformational analysis of polynucleotides. I. The favorable left-handed helical model for the poly(8,2'-S-cycloadenylic acid) with high anti conformation.

1) Energy calculations have shown that poly (8,2'-S-cycloadenylic aicd) can form left-handed helices owing to the high anti conformation. 2) Two favorable left-handed helices are characterized by axial translation per residue (Z=4.3 and 3.6A) and by rotations per residue (theta= 40 degrees and -25 degrees). 3) The proposed helical models might be stable in aqueous solution and is well explicable of the optical property of this compound.

Binding Sites↗
PubMed1976

Structural studies on the two forms of 8-bromo-2',3'-O-isopropylideneadenosine.

The crystal and molecular structures of two forms of 8-bromo-2',3'-O-isopropylideneadenosine have been determined by X-ray methods. In one form, the molecular structure has planar conformation in the sugar moiety and no intramolecular hydrogen bond. On the other hand, the molecular structure of the second form has C(2')-endo conformation and an intramolecular hydrogen bond. No stacking interaction between adjacent bases is found in either form, but two modes of the base-pairing hydrogen bond exist in the second form.

Adenosine↗
PubMed1976

The role of C1 esterase inhibitor in the activation of C1r, a subcomponent of the first component of complement from human plasma.

Clr was isolated from human serum by DEAE-cellulose column chromatography in the presence of EDTA. The isolated Clr did not hydrolyze N(alpha)-acetyl-L-arginine methyl ester, unless activated by brief treatment with trypsin [EC 3.4.21.4]. On thecolumn, the C1 esterase inhibitor activity was found to coincide with Clr but not C1s (another subcomponent of the first component) C1r was isolated from the euglobulin fraction of human serum by DEAE-cellulose column chromatograph. On Sephadex G-200 column chromatography, Clr was eluted in the void volume, whereas Clr was eluted in a position corresponding to a molecular weight of 140,000-160,000. The results indicated that, on activation, Clr was converted to an enzyme of lower molecular weight...

Chromatography, Ion Exchange↗
PubMed1976

Purification of human plasma kallikrein and urokinase by affinity chromatography.

L-Homoarginine benzylester was coupled with Sepharose 4B and used for affinity chromatography of human plasma kallikrein [EC 3.4.21.8] and urokinase [EC 3.4.99.26]. The euglobulin fraction of human plasma was treated with disodium ethylenediamine-tetraacetate (EDTA) and activated with acetone, and then kallikrein was purified 16-fold by affinity chromatography. The yield of kallikrein activity on affinity chromatography was 53%. The purified preparation of human plasma kallikrein appeared to be homogenous on gel electrophoresis. Commercial urokinase was also purified 4.8-fold with 64% yield by affinity chromatography.

Acetone↗
PubMed1976

Further studies on the mechanism of adrenaline-induced lipolysis in lipid micelles.

Lipase [EC 3.1.1.3] depleted lipid micelles, in which lipolysis was not elicited by adrenaline, were prepared from lipid micelles. When these lipase-depleted lipid micelles incubated with adipose tissue extract containing lipase activity, adrenaline-induced lipolysis was restored to almost the same level as that of native lipid micelles. Adrenaline-induced lipolysis was not restored when the lipase-depleted lipid micelles were homogenized or sonicated. Various tissue extracts from kidney, lung, liver, and pancreas, and post-heparin plasma, which contained lipase activity, restored adrenaline-induced lipolysis in lipase-depleted lipid micelles.

Adipose Tissue↗