Biomedical subjects

S Fujii

Publications and source records attributed to S Fujii.

At least 307 records · Page 17Linked to original sources

PubMed1997

Arotinoid mofarotene (RO40-8757) up-regulates p21 and p27 during growth inhibition of pancreatic cancer cell lines.

Effective chemotherapy for pancreatic cancer is urgently needed. The anti-proliferative activity of a new retinoid, mofarotene (RO40-8757), was compared with that of other retinoids, such as all trans-retinoic acid, 13-cis retinoic acid and 9-cis retinoic acid, on 9 pancreatic cancer cell lines in relation to the effects on various cell cycle-regulating factors. After treatment with each retinoid, anti-proliferative effect was determined by the MTT method and expression of cell cycle-regulating factors, such as cyclins (D1, E and A), cyclin-dependent kinases (2 and 4), cyclin-dependent kinase inhibitors (p21 and p27) and retinoblastoma protein, was analyzed by Western blotting. Mofarotene showed half-maximal inhibition of cell proliferation at concentrations between 0.14 x 10(-6) and 3.8 x 10(-6) mol/l with little cytotoxicity. In contrast, the other retinoids did not inhibit the growth of all cell lines by over 50% compared to controls. A marked increase in the fraction of cells in G1 phase of the cell cycle was observed after mofarotene treatment; this was associated with marked up-regulation of p21/p27 and a shift of retinoblastoma protein into the hypophosphorylated form. In conclusion, mofarotene inhibits the growth of pancreatic cancer cells by inducing G1-phase cell cycle-inhibitory factors (p21, p27 and hypophosphorylated form of Rb protein) and is considered to be a useful agent for pancreatic cancer treatment.

Alitretinoin↗

PubMed1997

Histochemical analysis of estrogen and progesterone receptors and gastric-type mucin in mucinous ovarian tumors with reference to their pathogenesis.

BACKGROUND: Mucinous tumors of the ovary have been thought to originate in two ways: by müllerian-type metaplasia of surface epithelium, and as monodermal teratomas. To gain a better understanding of their pathogenesis, the authors analyzed these tumors for their expression of estrogen receptors (ER) and progesterone receptors (PR) as markers of müllerian-type differentiation and for their content of gastric-type mucin as a marker of gastric differentiation. METHODS: The histochemical expression of ER, PR, and gastric-type mucin was studied in 10 specimens of the cervix with normal endocervical glands (as a representative of müllerian-derived mucin-containing cells), 3 ovary specimens with surface epithelial inclusion cysts that contained endocervical-like mucin-containing cells (representing müllerian-type metaplasia), and 47 mucinous tumors of the ovary (29 benign, 8 with low malignant potential, and 10 malignant). RESULTS: Normal endocervical glands expressed ER and PR and rarely expressed gastric-type mucin. Ovarian inclusion cysts showed strong expression of ER and PR in the cuboidal cells and drastically reduced expression in the endocervical-like mucin-containing cells. The cuboidal cells were negative for gastric-type mucin, but the endocervical-like mucin-containing cells expressed gastric-type mucin. Endocervical-like mucinous cells in benign and borderline mucinous tumors showed expression of PR and/or gastric-type mucin in all cases. CONCLUSIONS: The staining results for the inclusion cysts support the thesis that the endocervical-like mucinous cells encountered in the ones that express ER and PR weakly or not at all and have histochemical properties of normal gastric epithelium have their origin in metaplasia of müllerian-type epithelium. Application of the same staining methods to benign ovarian tumors and those with low malignant potential suggests strongly that similar müllerian-type metaplasia is a major pathway in their pathogenesis.

Adenocarcinoma, Mucinous↗

PubMed1997

Characterization of proviral DNA from an individual with long-term, nonprogressive infection with HIV-1 and nonrecoverable virus.

A small proportion of individuals infected with HIV-1 known as long-term nonprogressors (LTNPs) remain healthy and immunologically normal, with stable numbers of CD4+ lymphocytes, for prolonged periods without the administration of antiretroviral agents. The long terminal repeat (LTR) of HTV-1 proviral DNA of an LTNP from whom virus was consistently not recoverable has now been isolated by a nested polymerase chain reaction (PCR) method and shown to contain a total of 38 point mutations, only four of which affect promoter and enhancer elements, compared with the IIIB strain of HIV-1. Almost the entire HIV-1 proviral DNA was then isolated from the proband by a long PCR approach. Restriction enzyme digestion of the proviral DNA revealed no large deletions in the gag, pol, or env genes, although the loss of an Nco I site was apparent. Amplification of the env gene by long PCR also yielded a product apparently identical in size to that obtained with HIV-1 strain IIIB. Analysis by long PCR of HIV-1 proviral DNA from LTNPs with nonrecoverable virus may clarify the mechanism of long-term nonprogression and contribute to the development of HIV-1 vaccines.

Acquired Immunodeficiency Syndrome↗

PubMed1997

X-ray crystal structure determination and molecular dynamics simulation of prophospholipase A2 inhibited by amide-type substrate analogues.

X-ray crystal structures of bovine pancreas prophospholipase A2 (proPLA2) inhibited by two amide-type inhibitors, [(R)-2-dodecanoyl-amino-1-hexanolphosphocholine (DAHPc) and (R)-2-dodecanoylamino-1-hexanolphosphoglycol (DAHPg)], were determined to R = 0.208 and 0.215 using reflections with up to 2.1 A resolution, respectively. Both complex crystals lacked defined electron densities for the prosequence of the N-terminal and for a loop region consisting of residues 65-70, retaining the disordered feature observed in free proPLA2 despite stabilization due to complex formation. The polar and nonpolar moieties of the amide-type inhibitors were located in the calcium-binding pocket and in the N-terminal alpha-helical hydrophobic region of the enzyme, respectively. As for the amide group of the inhibitor, which is lacking in the true substrate, a strong hydrogen bond was formed between the NH of the inhibitor and the unprotonated N(delta1) atom of His-48, resulting in the tight binding of the inhibitor to proPLA2, as well as to PLA2. The 20-30 times more potent inhibitory activity of DAHPg than DAHPc toward PLA2 could be explained by hydrogen bond formation between the glycol OH of DAHPg and the carbonyl O of Asp-49. The seven residues of the N-terminal prosequence of proPLA2, though disordered, block the access of a water molecule to Ala-1 of PLA2 or change the hydrogen-bonding property of Ala-1 alpha-amino group, resulting in breakage of the water-mediated hydrogen-bond network which is commonly formed in PLA2. The results of molecular dynamics (MD) calculation in an aqueous solution at 300 K indicate that this, rather than the close contact between the prosequence and the residues 65-70 loop region, is the main reason why the latter region becomes flexible in proPLA2, compared with in PLA2.

Animals↗

PubMed1997

8-cyclopentyltheophylline, an adenosine A1 receptor antagonist, inhibits the reversal of long-term potentiation in hippocampal CA1 neurons.

The effects of an adenosine A1 receptor antagonist, 8-cyclopentyltheophylline (8-CPT, 1 microM), on the reduction of long-term potentiation were studied in CA1 neurons of guinea pig hippocampal slices. Reduction of long-term potentiation (depotentiation) was achieved by delivering a train of low-frequency afferent stimuli (low-frequency stimulation, 1000 pulses, 1 Hz) 20 min after the tetanus (100 Hz, 100 pulses). In control experiments, low-frequency stimulation reduced the potentiated component of the slope of the field EPSP and the amplitude of the population spike by 68.5 +/- 14.4% and 80.1 +/- 8.8%, respectively (n = 6); these values were significantly reduced to 13.4 +/- 9.7% and 9.0 +/- 10.9% (n = 7) when the low-frequency stimulation was applied during the perfusion with 8-CPT (1 microM). These results indicate that activation of adenosine A1 receptors enhances the depotentiation of long-term potentiation.

Animals↗

PubMed1997

The origin of an EPR signal observed in dithiocarbamate-loaded tissues. Copper(II)-dithiocarbamate complexes account for the narrow hyperfine lines.

We examined the electron paramagnetic resonance spectra of some copper(II)-dithiocarbamate complexes in various media at liquid nitrogen temperature. It is demonstrated that Cu(II)-dithiocarbamate complexes exhibit atypical spectra with narrow hyperfine splitting, and that the dithocarbamates forming a water-insoluble Cu(II) complex are permeable in tissues, while those yielding water-soluble complexes are not.

Animals↗

PubMed1997

A new butadiene derivative, T-686, inhibits plasminogen activator inhibitor type-1 production in vitro by cultured human vascular endothelial cells and development of atherosclerotic lesions in vivo in rabbits.

Plasminogen activator inhibitor-1 (PAI-1), the major physiologic inhibitor of tissue-type plasminogen activator and urokinase, is abundantly expressed in atherosclerotic vascular wall. To determine the role of PAI-1 in vascular wall, we have used a novel inhibitor of PAI-1, (3E, 4E)-3-benzylidene-4-(3,4,5-trimethoxy-benzylidene) -pyrrolidine-2,5-dione (T-686). T-686 was given to human vascular endothelial cells in vitro and to rabbits subjected to high cholesterol diet and mechanical injury in vivo. T-686 attenuated the augmentation of PAI-1 antigen accumulation induced by transforming growth factor beta in conditioned medium from the human umbilical vein endothelial cells. In rabbits with aortic atherosclerosis induced by hypercholesterolemia and implantation of indwelling plastic tubing, oral administration of T-686 (30mg/kg body weight/day) for 8 weeks attenuated the increase in plasma PAI-1 activity induced by vascular injury without decreasing blood triglyceride and cholesterol. This was accompanied by the reduction in aortic PAI-1 mRNA expression and the inhibition of development of atherosclerosis lesions. Thus, T-686 not only decreased PAI-1 synthesis in vascular cells in vitro but also protected against the development of vascular lesions in vivo. This compound may be useful in defining the role of PAI-1 in atherothrombotic states.

Animals↗

PubMed1997

Attenuation by gemfibrozil of expression of plasminogen activator inhibitor type 1 induced by insulin and its precursors.

BACKGROUND: Insulin and its precursors found in increased plasma concentrations in non-insulin-dependent diabetes mellitus (NIDDM) augment synthesis of plasminogen activator inhibitor type 1 (PAI-1) in Hep G2 cells in vitro and in rabbit liver in vivo. Reduced endogenous fibrinolysis secondary to increased PAI-1 activity may exacerbate atherogenesis. Recently, the reduction of the coronary heart disease incidence in the Helsinki Heart Study has implicated favorable modulation of endogenous fibrinolysis by gemfibrozil. METHODS AND RESULTS: In Hep G2 cells, 500 (700) mumol/L gemfibrozil decreased basal secretion of PAI-1 by 26% (43%) (P = .012 and P = .021, respectively) and attenuated insulin-induced (10 nmol/L) augmentation of PAI-1 in conditioned media by 61% (109%) (P = .010) within 24 hours. Inhibition was dependent on the duration of exposure (0 to 48 hours) and on the concentration of gemfibrozil (0 to 700 mumol/L) but not on the concentration of insulin (0.1 to 100 nmol/L). Gemfibrozil attenuated the augmentation of PAI-1 secretion induced by proinsulin (> 100%), by des(31,32)proinsulin (75%), and by des(64,65) proinsulin (77%) as well (10 nmol/L each). The specificity of these effects was confirmed by the unaltered levels of newly synthesized protein (metabolic labeling) and of total protein (both in conditioned media and cell lysates). Secretion of fibrinogen by Hep G2 cells was not affected by gemfibrozil. Changes in PAI-1 protein levels reflected modulation of PAI-1 gene expression as manifested by changes in levels of 3.2-kb PAI-1 mRNA (Northern blots). CONCLUSIONS: Gemfibrozil attenuated the augmentation of synthesis and secretion of PAI-1 induced by insulin and its precursors directly and specifically. Accordingly, gemfibrozil may exert favorable therapeutic effects normalizing impaired fibrinolysis in patients with hyperinsulinemia such as NIDDM.

Fibrinogen↗

PubMed1997

Contribution of the hydrophobic effect to the stability of human lysozyme: calorimetric studies and X-ray structural analyses of the nine valine to alanine mutants.

To clarify the contribution of the hydrophobic effect to the conformational stability of human lysozyme, a series of Val to Ala mutants were constructed. The thermodynamic parameters for the denaturation of these nine mutant proteins were determined using differential scanning calorimetry (DSC), and the crystal structures were solved at high resolution. The denaturation Gibbs energy (delta delta G) and enthalpy (delta delta H) values of the mutant proteins ranged from +2.2 to- 6.3 kJ/mol and from +7 to -17 kJ/mol, respectively. The structural analyses showed that the mutation site and/or the residues around it in some proteins shifted toward the created cavity, and the substitutions affected not only the mutations site but also other parts far from the site, although the structural changes were not as great. Correlation between the changes in the thermodynamic parameters and the structural features of mutant proteins was examined, including the five Ile to Val mutant human lysozymes [Takano et al. (1995) J. Mol. Biol. 254, 62-76]. There was no simple general correlation between delta delta G and the changes in hydrophobic surface area exposed upon denaturation (delta delta ASAHP). We found only a new correlation between the delta delta G and delta delta ASAHP of all of the hydrophobic residues if the effect of the secondary structure propensity was taken into account.

Alanine↗

PubMed1997

Some properties of nicked Vibrio vulnificus hemolysin.

Vibrio vulnificus, an opportunistic human pathogen, secretes the 50 kDa single-chain hemolysin. When incubated with an exocellular protease from this vibrio, the 50 kDa hemolysin was cleaved in some peptides joined with the disulfide bond(s); the 40 kDa fragment and the small fragment(s) undetectable in SDS-PAGE. The nicked hemolysin induced comparable hemolysis through the same process as that of the intact toxin. However, the nicked hemolysin was found to be more stable against inactivation due to autoaggregation, so that it formed a larger precipitation zone in the single radial immunodiffusion test using the antiserum against the intact hemolysin. These results suggest that V. vulnificus hemolysin is modified to be a more hydrophilic protein by nicking, while it is not accompanied by loss of the hemolytic activity.

Bacterial Proteins↗

PubMed1997

The effects of clomiphene citrate on normally ovulatory women.

OBJECTIVE: To investigate the efficacy of clomiphene citrate (CC) on normally ovulatory women who complained of infertility. DESIGN: A randomized study. SETTING: University Hospital. PATIENT(S): Thirty-three normally ovulatory women with unexplained infertility. INTERVENTION(S): Eighteen women received CC at a 50-mg dosage. Fifteen women received no ovulation-induction drugs. MAIN OUTCOME MEASURES: The pregnancy rate (PR) per patient, the PR per cycle, and the cumulative pregnancy rate. RESULT(S): Seven patients in the CC group stopped taking CC, and observations were terminated because of antiestrogenic effects. The pregnancy rate (PR) per patient and the PR per cycle were significantly decreased (P < 0.005) in the CC group (4 of 18 [22.2%] and 4 of 66 [6.1%], respectively) than in the spontaneous group (11 of 15 [73.3%] and 11 of 52 [21.2%], respectively). Kaplan-Meier tests showed that the cumulative pregnancy rate in the CC group was significantly lower than in the spontaneous group (P < 0.05). Five of seven patients who had stopped taking CC became pregnant in spontaneous cycles. CONCLUSION(S): Administration of CC to normally ovulatory women is not efficacious in terms of increasing the pregnancy rate.

Adult↗

PubMed1997

A prospective randomized comparison between long and discontinuous-long protocols of gonadotropin-releasing hormone agonist for in vitro fertilization.

OBJECTIVE: To investigate the efficacy of a discontinuous-long protocol in an IVF program. DESIGN: Prospective randomized study. SETTING: University hospital. PATIENT(S): One hundred thirty-seven IVF cycles of 92 patients in an outpatient IVF program from April 1995 to December 1995. INTERVENTION(S): In the discontinuous-long protocol group (n = 68), GnRH agonist (GnRH-a) was administered from the luteal phase until cycle day 7, when pure FSH administration was begun. In the long protocol group (n = 69), GnRH-a was administered until the day before hCG administration. MAIN OUTCOME MEASURE(S): Serum LH and ovarian steroid hormone levels, and IVF outcome. RESULT(S): The period and the total dosage of hMG were increased in the discontinuous-long protocol group. Although the fertilization rate was similar under both protocols, the number of embryos transferred was smaller and the cancellation rate was higher in the discontinuous-long protocol group because of the greater failure of oocyte retrieval and fertilization. Serum E2 levels in the late follicular phase were lower in the discontinuous-long protocol group. CONCLUSION(S): Early discontinuation of GnRH-a is not beneficial because of its adverse effects on follicular development.

Adult↗

PubMed1997

In vivo ESR-CT imaging of the liver in mice receiving subcutaneous injection of nitric oxide-bound iron complex.

ESR measurements and ESR-CT imaging of subcutaneously (SC) injected nitric oxide (NO)-bound iron complexes were conducted on the upper abdomen of live mice. The use of NO-bound iron complex with N-(dithiocarboxy)sarcosine resulted in a clear ESR-CT image showing high intensity areas in the ventral regions, while other NO-bound iron complexes with N-methyl-D-glucamine dithiocarbamate or N,N-diethyl-dithiocarbamate were inappropriate because of low S/N ratios. To investigate the distributions of SC injected NO-bound iron complexes in the abdomens of mice, we measured ESR signals in resected abdominal organs. The signal amplitude was higher in the resected liver than in the resected gastrointestinal organs or the blood samples. The findings suggest that the high intensity areas in the ESR-CT images thus obtained correspond to the liver.

Animals↗

PubMed1997

The effect of ultrasonic waves on the oxidation current of chlorpromazine in the 38 and 96 kHz-ultrasonic vibrating electrode voltammetry.

In the case of 38 and 96 kHz ultrasonic vibrating electrode (USVE) voltammetry of chlorpromazine, the oxidation current increased considerably with ultrasonic power (amplitude). Movement of the first oxidation product, crimson coloured cation radical, and the streaming of liquid in the neighbourhood of the USVE, were visually observed in order to understand the mechanism of the promotive effects of ultrasound on the oxidation reaction. The reaction profile of the oxidation of chlorpromazine in 38 kHz seems to be somewhat different from that in 96 kHz. However, the mechanical agitation of solution in the area nearest the electrode surface, which is essentially the same fundamental mechanism, takes place in both the cases of 38 and 96 kHz. Both micro- and macro-streamings due to the vibration of a small bubble on the electrode surface with a frequency lower than that of the ultrasonic wave were formed in 38 kHz. These streamings seemed to contribute to the agitation and the exchange of the solution near the electrode surface. However, at the same ultrasonic amplitude, the oxidation current at 96 kHz was much greater than that at 38 kHz. Such a promoting effect of ultrasound on the electrode reaction was considered to be due to the increase of the moving speed or to the acceleration of the particle in the solution.

Antipsychotic Agents↗

PubMed1997

Vitamin D analogues up-regulate p21 and p27 during growth inhibition of pancreatic cancer cell lines.

To obtain information regarding the growth-inhibitory effect of 1,25-dihydroxyvitamin D3 and its non-calcaemic analogue 22-oxa-1,25-dihydroxyvitamin D3 on pancreatic cancer cell lines, differences in the effects of G1-phase cell cycle-regulating factors were studied in vitamin D-responsive and non-responsive cell lines. Levels of expression of cyclins (D1, E and A), cyclin-dependent kinases (2 and 4) and cyclin-dependent kinase inhibitors (p21 and p27) were analysed by Western blotting after treatment with these compounds. In the responsive cells (BxPC-3, Hs 700T and SUP-1), our observations were: (1) marked up-regulation of p21 and p27 after 24 h treatment with 10(-7) mol l(-1) 1,25-dihydroxyvitamin D3 and 22-oxa-1,25-dihydroxyvitamin D3; and (2) marked down-regulation of cyclins, cyclin-dependent kinases and cyclin-dependent kinase inhibitors after 7 days' treatment. In non-responsive cells (Hs 766T and Capan-1), no such changes were observed. In conclusion, vitamin D analogues up-regulate p21 and p27 as an early event, which in turn could block the G1/S transition and induce growth inhibition in responsive cells.

Antineoplastic Agents↗

PubMed1997

Human T cell responses to recombinant mite antigens of Dermatophagoides farinae.

We studied T cell responses to four glutathione S transferase (GST)-fused mite antigens prepared in our laboratory using peripheral blood lymphocytes from mite-sensitive patients with bronchial asthma. Of the four recombinant antigens, purified GST-Mag3 had the strongest ability to cause patients' lymphocytes to proliferate, and its potency was almost comparable to that of crude mite bodies (Dfb) and faeces (Dff) antigens and a purified major antigen, Der f 2. The responder lymphocytes were mainly T cells, because the proliferative response was depleted by the treatment of lymphocytes with anti-CD3 antibody and complement, but not with anti-CD20 antibody and complement. The responsiveness of lymphocytes to GST-Mag3 correlated with that to Der f 2, but GST-Mag3 displayed slightly higher activity to stimulate lymphocytes than Der f 2. Simultaneously, the levels of Dff- and GST-Mag3-specific IgE antibodies correlated with the responsiveness of lymphocytes to GST-Mag3. These results suggest that Mag3 is a new valuable antigen for the response of T cell proliferation in mite-sensitive patients.

Allergens↗

PubMed1997

Barotolerance is dependent on both trehalose and heat shock protein 104 but is essentially different from thermotolerance in Saccharomyces cerevisiae.

The contribution of trehalose and hsp104 to barotolerance in Saccharomyces cerevisiae has been investigated. Mutant strains, which lacked the ability to accumulate trehalose and/or hsp104, were examined for barotolerance and thermotolerance. All the mutants showed lower barotolerance and thermotolerance than their control strains. Trehalose had a greater protective effect towards high pressure than high temperature. Thus, trehalose and hsp104 are important factors for barotolerance and thermotolerance, but trehalose is more important for barotolerance than for thermotolerance.

Heat-Shock Proteins↗

PubMed1997

Distribution and heterogeneity of mast cells in the human uterus.

Mast cells (MCs) are widely distributed in most human tissues. Those cells that contain only tryptase are designated as T-MCs, while those that also contain chymase are referred to as TC-MCs. This study uses immunohistochemical staining for tryptase and chymase to assess the distribution and heterogeneity of these two types of MCs in the human uterus. The greatest number of MCs was found in the inner (i.e. luminal) half of the myometrium, with this area containing approximately equal proportions of T-MCs and TC-MCs. There were fewer MCs in the outer half of the myometrium and the cervix, but the proportion of TC-MCs in both of these areas was substantially higher. In contrast, the endometrium contained significantly fewer MCs, but proportionally more T-MCs. There was no change in the number of MCs between the proliferative and secretory phases of the menstrual cycle; however, there was a significantly lower number in all areas after menopause. Most of the MCs were observed in close association with uterine smooth muscle cells, as well as in the vicinity of fibroblasts and collagen, and it appears they may play an important role in the reconstruction of uterine tissues during the menstrual cycle.

Cell Count↗