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Y Suhara

Publications and source records attributed to Y Suhara.

At least 19 recordsLinked to original sources
PubMed2001

Efficient and versatile synthesis of novel 2alpha-substituted 1alpha,25-dihydroxyvitamin D(3) analogues and their docking to vitamin D receptors.

Novel 2alpha-substituted 1alpha,25-dihydroxyvitamin D(3) analogues with 2alpha-alkyl and 2alpha-hydroxyalkyl groups were systematically synthesized from D-xylose. Their conformation on binding to the ligand binding domain (LBD) of the vitamin D receptor was analyzed. It has been found that the 2alpha-hydroxypropyl group best fits the cavity of the LBD, and the binding activity is three times higher than that for the natural hormone.

Calcitriol↗
PubMed2001

Synthesis and biological activities of novel structural analogues of 2-arachidonoylglycerol, an endogenous cannabinoid receptor ligand.

Novel analogues of 2-arachidonoylglycerol (2-AG), an endogenous cannabinoid receptor ligand, were developed. Chemical synthesis of these analogues (2-AGA105 and 2-AGA109) was accomplished starting from 2-octyn-1-ol and diethyl malonate and employing Wittig coupling of triene phosphonate with an aldehyde intermediate in a convergent and stereoselective manner. These analogues should be useful lead compounds for the development of novel 2-AG mimetics.

Aldehydes↗
PubMed2000

A concise and efficient route to 2alpha-(omega-hydroxyalkoxy)-1alpha,25-dihydroxyvi tam in D3: remarkably high affinity to vitamin D receptor.

[reaction: see text]A convenient and potentially valuable synthetic approach to the novel 2alpha-functionalized 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] derivatives (1a-c), which are the C2-epimer of ED-71 and its analogues, has been developed. The C2alpha-modified ring A precursors (1,7-enynes 16, n = 0, 1, and 2) were constructed stereoselectively starting from D-glucose in high yield. In the synthesized 2alpha-(omega-hydroxyalkoxy)-1alpha,25(OH)2D3 derivatives, 1a and 1b showed a greater binding affinity to vitamin D receptor (VDR), up to 1.8 times that of the native hormone.

Animals↗
PubMed2000

Syntheses and biological evaluation of novel 2alpha-substituted 1alpha,25-dihydroxyvitamin D3 analogues.

Novel 2alpha-substituted 1alpha,25-dihydroxyvitamin D3 analogues were efficiently synthesized and their biological activities were evaluated. 2alpha-Methyl-1alpha,25-dihydroxyvitamin D3 (2), whose unique biological activities were previously reported, was modified to 2alpha-alkyl (ethyl and propyl) and 2alpha-hydroxyalkyl (hydroxymethyl, hydroxyethyl, and hydroxypropyl) analogues 3-7 by elongation of the alkyl chain and/or introduction of a terminal hydroxyl group. 2alpha-Hydroxypropyl-1alpha,25-dihydroxyvitamin D3 (7) exhibited an exceptionally potent calcium-regulating effect and a unique activity profile.

Biochemistry↗
PubMed2000

Evidence that 2-arachidonoylglycerol but not N-palmitoylethanolamine or anandamide is the physiological ligand for the cannabinoid CB2 receptor. Comparison of the agonistic activities of various cannabinoid receptor ligands in HL-60 cells.

We examined the effect of 2-arachidonoylglycerol, an endogenous cannabinoid receptor ligand, on the intracellular free Ca(2+) concentrations in HL-60 cells that express the cannabinoid CB2 receptor. We found that 2-arachidonoylglycerol induces a rapid transient increase in intracellular free Ca(2+) concentrations in HL-60 cells. The response was affected by neither cyclooxygenase inhibitors nor lipoxygenase inhibitors, suggesting that arachidonic acid metabolites are not involved. Consistent with this notion, free arachidonic acid was devoid of any agonistic activity. Importantly, the Ca(2+) transient induced by 2-arachidonoylglycerol was blocked by pretreatment of the cells with SR144528, a CB2 receptor-specific antagonist, but not with SR141716A, a CB1 receptor-specific antagonist, indicating the involvement of the CB2 receptor but not the CB1 receptor in this cellular response. G(i) or G(o) is also assumed to be involved, because pertussis toxin treatment of the cells abolished the response. We further examined the structure-activity relationship. We found that 2-arachidonoylglycerol is the most potent compound among a number of naturally occurring cannabimimetic molecules. Interestingly, anandamide and N-palmitoylethanolamine, other putative endogenous ligands, were found to be a weak partial agonist and an inactive ligand, respectively. These results strongly suggest that the CB2 receptor is originally a 2-arachidonoylglycerol receptor, and 2-arachidonoylglycerol is the intrinsic natural ligand for the CB2 receptor that is abundant in the immune system.

Amides↗
PubMed2000

Synthesis and biological activities of 2-arachidonoylglycerol, an endogenous cannabinoid receptor ligand, and its metabolically stable ether-linked analogues.

We synthesized 2-arachidonoylglycerol (1), an endogenous cannabinoid receptor ligand, and its metabolically stable ether-linked analogues. Compound 1 was synthesized from 1,3-benzylideneglycerol (6) and arachidonic acid in the presence of N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine followed by treatment with boric acid and trimethyl borate. An ether-linked analogue of 2-arachidonoylglycerol (2) was synthesized from 6 and 5,8,11,14-eicosatetraenyl iodide (9). The ether-linked analogues of 2-palmitoylglycerol (4) and 2-oleoyglycerol (5) were synthesized from 6 and hexadecyl iodide (12) and 9-octadecenyl iodide (14), respectively. We confirmed that 1 stimulates NG108-15 cells to induce rapid transient elevation of the intracellular free Ca2+ concentrations through a CB1 receptor-dependent mechanism. Noticeably, 2 exhibited appreciable agonistic activity, although its activity was significantly lower than that of 1. Compound 2 would be a useful tool in exploring the physiological significance of 1, because this compound is resistant to hydrolyzing enzymes in contrast to 1. On the other hand, the ether-linked analogues of either 4 or 5 failed to act as a CB1 receptor agonist. Compounds 4 and 5 would also be valuable as control molecules in experiments where 2 is employed.

Animals↗
PubMed2000

Screening for proteinuria in Japanese schoolchildren: a new approach.

By governmental mandate, Japanese school children are screened annually for proteinuria, hematuria, and glucosuria to identify children with possible renal disorders. We added urine dipstick tests for albumin and creatinine to the Japanese screening protocol, and used their dipstick results for blood, glucose and protein. The sulfosalicylic acid precipitation test was used to confirm "trace" positive protein dipsticks. The Japanese and our screening protocol have in common the same data for glucosuria and proteinuria. Their scheme has an algorithm for repeat testing of children with abnormal results, and further testing and medical evaluation for those showing persistently abnormal values. Out of the 23,121 students, we found seven with likely nephritis, one with confirmed nephritis, one with nephrotic syndrome, 170 with persistent unexplained hematuria, 19 with persistent unexplained proteinuria, 14 cases of urinary tract infection, and 20 cases of likely diabetes mellitus. We conclude that dipstick testing for albumin, protein, creatinine, glucose and occult blood has significant value in a multilevel testing scheme for identifying children with urinary tract abnormalities or diabetes. The assay of albumin increases the sensitivity of the screening, and dividing the albumin by the creatinine concentration reduces the potential errors arising from concentrated or dilute urines.

Adolescent↗
PubMed1999

Evidence that the cannabinoid CB1 receptor is a 2-arachidonoylglycerol receptor. Structure-activity relationship of 2-arachidonoylglycerol, ether-linked analogues, and related compounds.

An endogenous cannabimimetic molecule, 2-arachidonoylglycerol, induces a rapid, transient increase in intracellular free Ca2+ concentrations in NG108-15 cells through a cannabinoid CB1 receptor-dependent mechanism. We examined the activities of 24 relevant compounds (2-arachidonoylglycerol, its structural analogues, and several synthetic cannabinoids). We found that 2-arachidonoylglycerol is the most potent compound examined so far: its activity was detectable from as low as 0.3 nM, and the maximal response induced by 2-arachidonoylglycerol exceeded the responses induced by others. Activities of HU-210 and CP55940, potent cannabinoid receptor agonists, were also detectable from as low as 0.3 nM, whereas the maximal responses induced by these compounds were low compared with 2-arachidonoylglycerol. Anandamide was also found to act as a partial agonist in this assay system. We confirmed that free arachidonic acid failed to elicit a response. Furthermore, we found that a metabolically stable ether-linked analogue of 2-arachidonoylglycerol possesses appreciable agonistic activity, although its activity was apparently lower than that of 2-arachidonoylglycerol. We also confirmed that pretreating cells with various cannabinoid receptor agonists nullified the response induced by 2-arachidonoylglycerol, whereas pretreating cells with other neurotransmitters or neuromodulators did not affect the response. These results strongly suggested that the cannabinoid CB1 receptor is originally a 2-arachidonoylglycerol receptor, and 2-arachidonoylglycerol is the intrinsic physiological ligand for the cannabinoid CB1 receptor.

Animals↗
PubMed1996

Comparison of the biological activity of synthetic N-acylated asparagine or serine linked monosaccharide lipid A analogs.

The mitogenicity, lethal toxicity, induction of tumor necrosis factor (TNF), production of nitric oxide (NO) and antitumor activity against Meth A fibrosarcoma by chemically synthesized N-acylated asparagine-linked (A-701, A-702 and A-703) or N-acylated serine-linked (A-607) nonphosphorylated acylglucosamine and 4-0-phosphorylated acylglucosamine (A-103) derived lipid A analogs were determined. compound A-607 (with tetradecanoyl and (R)-3-tetradecanoyloxytetradecanoyl at the C-2 and C-3 positions) induced a significant incorporation of 3H-thymidine into splenocytes of C3H/He mice at concentrations ranging from 3.13 to 50 microM, but the mitogenic activity of A-701 (2-N-acetylglucosamine), A-702 (tetradecanoyl at the C-2), and A-703 (with (R)-tetradecanoyloxytetradecanoyl and tetradecanoyl at the C-2 and C-3) was very weak. The lethality of A-703 and A-103 (with (R)-3-tetradecanoyloxytetradecanoyl at the C-2 and C-3) was weaker than that of A-607 at doses of 300 and 750 nmol/kg in C57BL/6 mice loaded with D-galactosamine. Peritoneal macrophages, stimulated with A-701-A-703, caused production of TNF which induce L929 cell lysis in vitro, and A-703 showed a high production of TNF. The compounds, except for A-607, exhibited little NO production by macrophages, but did induce the NO production in the presence of interferon gamma. Induction of TNF and NO inducible activity by A-703 was lower than that of A-607. A-703, A-607 and A-103 showed antitumor activity against Meth A fibrosarcoma in BALB/c mice. When A-703 or A-103 with muramyl dipeptide was administered, A-703 failed to show combined effects, but A-103 did. We concluded from these findings that the biological potency of asparagine compounds appears to be placed between serine- and amino-free compounds.

Acylation↗
PubMed1995

Disaccharides as endomannosidase inhibitors: syntheses of alpha-homomannojirimycin and beta-homomannojirimycin linked to D-glucose and D-mannose.

4-O-(alpha-D-Glucopyranosyl)-alphaHMJ (Glcalpha1,4HMJ), 4-O-(alpha-mannopyranosyl)-alphaHMJ (Manalpha1,4alphaHMJ), 4-0-(alpha-glucopyranosyl)-betaHMJ (Glcalpha1,4betaHMJ), and 4-0-(alpha-mannopyranosyl)-betaHMJ (Manalpha1, 4betaHMJ) were synthesized as endomannosidase inhibitors which are potentially useful both for probing the pathways of N-linked glycoprotein processing and for the chemotherapy of some viral diseases.

1-Deoxynojirimycin↗
PubMed1994

Protective effect of sodium L-malate, an active constituent isolated from Angelicae radix, on cis-diamminedichloroplatinum(II)-induced toxic side effect.

The effects of ingredients of Shi-Quan-Da-Bu-Tang (Juzen-taiho-to) on the nephrotoxicity and bone marrow toxicity caused by i.p. administration of 3 mg/kg cis-diamminedichloroplatinum (II) (CDDP) 9 times (on days 3, 4, 5, 6, 7, 8, 10, 11, 12) were examined in ddY mice s.c. inoculated with sarcoma 180 (S-180) cells on day 1. Angelicae Radix showed the strongest protective effect against the toxicity among the ingredients. The ED50 of a water extract of Angelicae Radix was 17.8 mg/kg for nephrotoxicity (indicated by an increase in blood urea nitrogen) and 59.4 mg/kg for bone marrow toxicity (indicated by a decrease in white blood cell count), when it was administered perorally (p.o.) on days, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15. The water extract did not exert any significant effect on the antitumor activity of CDDP. Bioassay-directed fractionation of the water extract resulted in isolation of a constituent having protective effects against the toxicity: sodium L-malate, C4H4Na2O5, was found to exhibit protective effects against both nephrotoxicity (ED50: 0.4 mg/kg, p.o.) and bone marrow toxicity (ED50: 1.8 mg/kg, p.o.), without reducing the antitumor activity of CDDP. These findings indicate that Angelicae Radix and its constituent sodium L-malate could provide significant protection against CDDP-induced nephrotoxicity and bone marrow toxicity without reducing the antitumor activity.

Animals↗
PubMed1991

Effect of co-administration of granulocyte colony-stimulating factor on interferon therapy.

The effect of co-administration of granulocyte colony-stimulating factor (G-CSF), as an antineutropenia agent, on interferon therapy was examined in a mouse model, in anticipation of an enhancement of interferon efficacy, because neutrophils induced by G-CSF are thought to act as antitumor effectors. G-CSF was intraperitoneally co-administered with human interferon alpha A/D (IFN) on Day 6 to Day 10 after intradermal inoculation of Meth A fibrosarcoma. Although the co-administration of G-CSF could protect against neutropenia and leukopenia induced by IFN, it did not enhance the regression of tumor, and rather reduced the prolongation of survival time and the long-term survival incidence of IFN therapy. The subsequent in vitro study showed that the antiproliferative activity of peripheral blood leukocytes from Meth A-bearing mice given both IFN and G-CSF was much weaker than that of mice given IFN alone. Whether the observed nullifying effect of G-CSF on IFN therapy is also the case with tumors other than Meth A is open to further study.

Animals↗
PubMed1991

[Circulating immune complexes and complement breakdown products in childhood IgA nephropathy].

Circulating immune complexes (CIC), mainly IgA-CIC have been frequently detected in IgA nephropathy and recently increased levels of C3 fragments which indicate C3 activation have been reported. However, little is known about the relationship between CIC and complement activation. We determined CIC by the solid-phase anti-C3 Facb enzyme immunoassay in 37 children with IgA nephropathy to investigate the relationship between CIC and clinical and/or histological findings, and also determined C3 fragments whether CIC correlate with complement activation. IgA-CIC were detected in 78% (27/37) with a mean level of 11.9 +/- 3.9 micrograms/ml, which was significantly higher than other glomerular diseases (P less than 0.05). IgA-CIC levels were also found significantly higher in 27 cases with proteinuria than in 10 cases without proteinuria (P less than 0.05). IgG-CIC were detected in 67% (12/18) with a mean level of 4.1 +/- 2.6 micrograms/ml, which was not significantly different from other glomerular diseases. No striking correlation was noted to exist between CIC levels at renal biopsy and the histological severity, because CIC are often present intermittently. C3d was quantitated by the rocket immunoelectrophoresis and C3 by the single radial immunodiffusion to determine the C3d/C3 ratio. The mean value of C3d/C3 was 0.63 +/- 0.19 which was significantly higher than a corresponding value for 15 healthy controls of 0.27 +/- 0.06 (P less than 0.05). Levels of IgA-CIC were found to have a significant positive correlation between C3d/C3 determined simultaneously in 33 cases (r = 0.43, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Antitumor activity of T cells in lymphoid organs induced by interferon in tumor-bearing mice.

Administration of human hybrid interferon-alpha A/D (IFN) for 5 consecutive days induced antitumor activity in spleen of Meth A fibrosarcoma-bearing mice 9-10 days after cessation of IFN administration. Antitumor activity assayed by the in vivo neutralization test was found in the spleen of responding mice but not in that of progressive mice. This activity was T-cell-dependent and tumor-selective. However, tumor-neutralizing activity was not found in spleen recovered as early as 3 days after cessation of IFN administration when many tumor cells are still surviving in tumor nodules and being attacked by the host. Instead, T-cell-dependent and tumor-selective tumor-neutralizing activity was found in the lymph node of tumor-bearing mice at this early stage. Furthermore, the tumor-neutralizing activity was already detected in the lymph nodes during the course of IFN administration, although there was no difference in the cell composition of the lymph nodes of IFN- and placebo-administered mice. Since IFN-alpha is apparently not a direct modifier of T cells, these results indicate that IFN probably did not directly increase the number of antitumor T cells but instead modified the host-tumor interaction in such a way that, as an early event, the enhanced T-cell response to tumor cells occurred, resulting in an increase in the antitumor T-cell population in lymph nodes. We supposed that, as the tumor regressed, these antitumor T cells would eventually leave the lymph node and migrate to the spleen.

Animals↗
PubMed1990

Production of antitumor mononuclear blood cells in tumor-bearing mice by interferon-alpha A/D therapy.

Administration of human interferon-alpha A/D (IFN-alpha A/D) to Meth A fibrosarcoma-bearing mice produced mononuclear blood cells with antiproliferation activity that were able to suppress Meth A growth in vitro. Their production depended on IFN doses and administration intervals. They were short-lived since antiproliferation activity was not detectable in mononuclear cells 2 days after cessation of IFN administration, although it was detectable as long as IFN administration continued. A similar production of antiproliferative mononuclear blood cells by IFN was achieved in tumor-free as well as in tumor-bearing mice, indicating no deleterious effect of the growing tumor on the production of these cells. IFN-induced antiproliferation activity was not tumor-specific since mononuclear blood cells of IFN-administered mice bearing either Meth A and Meth 1, another antigenically distinct fibrosarcoma, suppressed the in vitro growth of both Meth A and Meth 1 cells. T cells were not involved in the in vivo production of antiproliferative mononuclear blood cells by IFN therapy because the cells with this activity were produced in vivo in Meth A-bearing athymic mice and also in Meth A-bearing mice with reduced T-cell populations by the treatment with alpha mouse thymocyte globulin. T cells were not involved in their antiproliferation activity either, since the in vitro T-cell depletion of mononuclear cells did not diminish this antiproliferation activity. Because mononuclear cells surviving the in vitro T cell depletion were positive for AcM.1 (an epitope of activated macrophage) and also because the alpha Mac-1 antibody completely abolished their in vitro antiproliferation activity, this led us to conclude that it was activated monocytes in blood that were produced by IFN in a T-cell-independent fashion and that these monocytes were the cells responsible for the observed in vitro antiproliferation activity.

Animals↗