Biomedical subjects

Y Hashimoto

Publications and source records attributed to Y Hashimoto.

At least 613 records · Page 34Linked to original sources

PubMed1996

In vivo direct measurement of the bronchodilating effect of sevoflurane using a superfine fiberoptic bronchoscope: comparison with enflurane and halothane.

OBJECTIVES: Although volatile anesthetics have been shown to have spasmolytic effects on constricted airways, most previous studies were performed to assess bronchodilation with indirect methods such as measurement of airway resistance, whose reliability is controversial. As the authors have developed a new direct method using a superfine fiberoptic bronchoscope (SFB) and confirmed the accuracy of this method, this study assessed the spasmolytic effect of sevoflurane (S) as compared with enflurane (E) and halothane (H). DESIGN: Open-labeled, randomized study. SETTING: The study protocol was approved by the Animal Care Committee in a school of medicine. PARTICIPANTS: Twenty-two mongrel dogs. INTERVENTIONS: The dogs were anesthetized with pentobarbital, IV, paralyzed with pancuronium, and the lungs were mechanically ventilated. The endotracheal tube had an additional lumen to insert the SFB (outer diameter 2.2 mm). The tip of the SFB was located between a second and third bronchial bifurcation to continuously monitor the bronchial cross-sectional area (BCA) of third or fourth generation bronchi. The BCA was printed out by videoprinter at the end of expiration and was calculated on a Macintosh IIci computer using an NIH (National Institutes of Health) image program. Bronchoconstriction was produced with histamine (HA: 10 micrograms/kg + 500 micrograms/kg/hr). In the first protocol, 4 mongrel dogs were used to assess the accuracy of the new method. BCA was measured 30 and 60 minutes after the placement of the SFB and also 30 and 60 minutes after the start of the histamine (HA) infusion. Arterial blood (4 mL) was collected at 30 and 60 minutes after placement of the SFB to measure the plasma concentration of catecholamines with gas chromatographic mass spectrometry. In the second protocol, 18 dogs were randomly allocated to 3 groups of 6 each: group S, group E, and group H. Thirty minutes after the start of the HA infusion, the dogs subsequently inhaled the following concentrations of S, E, or H for 15 minutes: 0.2, 0.4, 0.8, and 1.6 minimum alveolar concentrations. The BCA was assessed before and 30 minutes after the start of HA and at the end of the inhalation period of each concentration. MEASUREMENTS AND MAIN RESULTS: In the first study, no significant differences in the BCA were found between 30 and 60 minutes after the placement of the SFB and between 30 and 60 minutes after the start of HA. The plasma concentrations of norepinephrine and epinephrine changed from 138 +/- 45 and 162 +/- 18 to 188 +/- 48 and 136 +/- 18 pg/mL, respectively. In the second study, all volatile anesthetics significantly increased the BCA in a dose-dependent manner. There was no significant difference among the three groups. CONCLUSION: As the BCA did not change in the first study, the tip of the SBF could be well fixed, and the 30-minute interval is long enough for the HA infusion to produce stable bronchoconstriction. The plasma catecholamine concentrations suggest that the pentobarbital anesthesia was deep enough to inhibit the direct irritant effect of the endotracheal tube and the SFB on the airway. This new direct method indicates that S dilates HA-constricted proximal airway with the same potency as E and H.

Anesthetics, Inhalation↗

PubMed1996

The pharmacodynamics of 6-(3-dimethylaminopropionyl)forskolin and a possible metabolite in beagles.

A specific gas chromatography/mass spectroscopy method with a detection limit of 0.1 ng/mL was developed for the measurement of 6-(3-dimethylaminopropionyl)forskolin (1) in beagle plasma. Using this method, plasma concentrations of 1 in beagles given pharmacologically effective intravenous doses of 1.HCl were determined. The observed maximal plasma concentrations rapidly decreased with time, and half-lives of the alpha-phases were < 9 min. Pharmacological effects of 1 on the cardiovascular parameters were simultaneously evaluated in one of the studies. Decreases of the pharmacological effects were slower than decreases in plasma concentration of 1. In addition, 6-(3-methylaminopropionyl)forskolin (N-monodemethyl 1), an expected initial metabolite of 1, was prepared and found to be as pharmacologically active as 1 in beagles. These results and others strongly suggest that a metabolite(s) of 1 contributes to the pharmacological effects of 1 in beagles.

Animals↗

PubMed1996

Flavonoid-mediated tumor growth suppression demonstrated by in vivo study.

Many of flavonoids as well as bioflavonoids extracted from higher plants, which were earlier revealed to have tumor cell growth suppression activity in vitro, were examined for their effect on tumors in vivo. Balb/c mice were inoculated i.p. with syngeneic tumor cells, meth/a, and then provided with flavonoids dissolved in their drinking water during the course of their survival time. Many flavonoids were effective in prolonging the survival period. Furthermore, flavonoids that did not show suppressive activities in the in vitro experiments were effective in the in vivo assay. The data suggested that sugar bonded to the A ring, which suppresses tumor growth inhibition in vitro, plays an important role. Many aglycones that were effective in the in vitro assay on the tumor growth suppression were not effective in the in vivo assay. The reason for this seems to be that most aglycones are unstable and thus break down in vivo. No acute nor chronic toxicity of flavonoids was observed in the mice.

Animals↗

PubMed1996

Influence of OH group and sugar bonded to flavonoids on flavonoid-mediated suppression of tumor growth in vitro.

Many flavonoids extracted from higher plants, synthesized or purified flavonoids, and their aglycones showed anti-tumor activity. Using purified or synthesized flavonoids, we studied the effect of the chemical structure of 2-benzoic flavone on the growth of human tumor cells (HCT-15 in vitro. The type of sugar combined with the A phenol of flavonoids played an important role in the tumor suppression; i.e., glucose attachment at the A phenol caused suppression of tumor cell growth, but other sugars such as rhamnose and lutinoside at that position did not suppress the growth of the cells. OH groups bonded to the B phenol also had a great effect on the growth. Flavonoids with OH groups conjugated to the 3', 4', and 5' of B phenol were stronger in anti-tumor effect than those with the OH groups attached at the 3' and 4' or 4' only, although anthocyanins were generally more effective than the other flavonoids.

Antineoplastic Agents, Phytogenic↗

PubMed1996

Antitumor effect of hydrolyzed anthocyanin from grape rinds and red rice.

When Balb/C mice that were fed with red glutinous rice, white ordinary rice, or commercially available standard food were inoculated with syngeneic Meth/A lymphoma cells i.p., the group fed the red rice survived longer than the other two groups. In order to determine if the anthocyanins contained in red-coloured seeds and fruit rinds were responsible for the tumor suppressive effect, we added anthocyanins extracted from grape rinds and glutinous red rice to petri dishes that had been seeded with HCT-15 cells. After 4 days of culture, cell counts were made. These anthocyanins were not effective in suppressing the tumor growth. However, anthocyanidins, which were generated by keeping anthocyanins in 5 to 6% HC1 methanol for 5 to 6 hours, were effective in the suppression of tumor growth. Flowcytometric histograms were made after 2 days of culture with these bioflavonoids. The histogram of cells treated with crude anthocyanin was similar to that of the control. Hydrolyzed anthocyanidins gave the elevation of S phase, suggesting a block in the step from S-phase to G2-phase. It seemed that the anthocyanidins contained in the grape rinds and red rice were effective on the suppression of cell growth as observed previously for anthocyanins extracted from the petals of higher plants.

Animals↗

PubMed1996

Distinct binding patterns of HS1 to the Src SH2 and SH3 domains reflect possible mechanisms of recruitment and activation of downstream molecules.

We previously identified a gene, LckBP1, which encodes a protein that binds to the Lck SH3 domain and is identical to murine SH1. Using unstimulated T lymphocytes, we further demonstrated that Lck binds to HS1 in vivo and that HS1 is tyrosine phosphorylated upon TCR stimulation. In the present report, we analyzed the binding pattern of several src kinases and HS1 in greater detail. The Lck SH3 domain binds to HS1 constitutively, while the Lck SH2 domain associates with HS1 only upon TCR stimulation. A similar binding pattern was observed with Lyn and HS1, but not with Fyn and HS1, in which the Fyn SH2 region associates with HS1 upon TCR stimulation but the Fyn SH3 region does not associate with HS1 regardless of TCR stimulation. Such distinct binding patterns of the src kinase SH2 and SH3 domains to HS1 may represent a mechanism by which src family kinases select substrates and activate particular downstream signaling pathways.

Adaptor Proteins, Signal Transducing↗

PubMed1996

Absorption and metabolism of lipids in rats depend on fatty acid isomeric position.

This study determined the effect of dietary (dipalmitoyl) triacylglycerol (TAG) structure on the absorption and metabolism of fat in the presence or absence of cholesterol. Sprague-Dawley male rats weighing approximately 180 g were fed diets containing 10 g/100 g diet 1,3-dipalmitoyl-2-oleoyl-glycerol-rich oil (POP) or 1(3),2-dipalmitoyl-3(1)-oleoyl-glycerol-rich oil (PPO), either with or without cholesterol supplementation (0.5 g/100 g diet), for 2 wk. There were no differences in the growth of rats fed the various diets. The apparent absorption efficiency of dietary fat especially the apparent absorption efficiency of palmitic acid, was significantly lower in the POP groups than in the groups fed the PPO diets. The excretion of cholesterol in feces of rats fed the POP diet with cholesterol was significantly greater than those fed the PPO diet containing cholesterol. The excretion of total bile acids in the rats fed cholesterol was significantly greater than in those fed the diets without cholesterol. Liver cholesterol was significantly greater in rats fed cholesterol and was not affected by the TAG structure. Plasma cholesterol was significantly lower in the POP dietary groups than in the PPO groups. These results suggest that the absorption and metabolism of fat depend on the positional isomer of the fatty acid.

Absorption↗

PubMed1996

A mutation study of catalytic residue Asp 52 in hen egg lysozyme.

We constructed a system for the expression and secretion of mature hen lysozyme by yeast using an intermediate "secretion-signal cassette" vector, pKP1700, containing the yeast invertase signal sequence and an expression vector, pAM82, for secretion and maturation of the enzyme. Using this system, mutants of hen lysozyme were produced and the catalytic mechanism in hen lysozyme was definitely confirmed. The hydrolytic activity of D52A as to substrate (NAG)6 at pH 5.0 was obviously decreased to one-four hundredth of that of the wild type. The acidic limb of the pH-activity profile observed for the wild-type was not observed for D52A, and the pKa of Glu 35 on the alkaline limb was seen for both enzymes. Moreover, no structural change was detected on X-ray analysis of D52A. Therefore, we confirmed that dissociated Asp 52 assists catalysis by producing an electrostatic field and by stabilizing the oxocarbonium ion intermediate in the dissociated form.

Animals↗

PubMed1996

Stabilization of lysozyme by introducing N-glycosylation signal sequence.

We designed mutant lysozymes with N-glycosylation signal sequences (Asn48-Gly49-Thr-50 and Asn87-Ile88-Thr89) by substituting Asp to Asn at positions 48 and 87. When these mutant lysozymes were expressed by using yeast (Saccharomyces cerevisiae) in Burkholder minimum medium, N-glycosylation occurred in both lysozymes. The mutant lysozyme with the oligosaccharide at Asn87 showed a similar character to a reported polymannosyl lysozyme [Nakamura, Takasaki, Kobayashi, and Kato (1993) J. Biol. Chem. 268, 12706-12712; Kato, Takasaki, and Ban (1994) FEBS Lett. 355, 76-80]. As judged from the thermodynamic stabilities of the lysozymes obtained by the guanidine hydrochloride denaturation method, the oligosaccharide-bearing mutant lysozymes were more stable by 0.4-1.6 kcal/mol than the corresponding unglycosylated lysozymes. Therefore, it is suggested that the introduction of an N-glycosylation signal sequence into a protein is an effective means to increase the stability of the protein.

Amino Acid Sequence↗

PubMed1996

Expression of the cholera toxin B subunit in the Golgi apparatus of Swiss 3T3 cells inhibits DNA synthesis induced by basic fibroblast growth factor.

We attempted to express the cholera toxin B subunit (CTXB) in the Golgi apparatus of cultured mammalian cells by means of gene transfection. Complementary DNA of CTXB was ligated with the Golgi-retention signal sequence of human beta 1,4 galactosyltransferase cDNA, and the chimeric gene yielded was inserted into a mammalian expression vector. The resultant construct was transfected into COS-1 cells for transient expression and into Swiss 3T3 cells for stable expression. The expression of a fusion protein encoded by the chimeric gene was demonstrated according to the following criteria: first, detection of a protein exhibiting the expected molecular mass on Western blot analysis using an anti-CTXB antibody; second, detection of the protein located in the Golgi area by indirect immunofluoresence microscopy; and third, detection of GM1 binding activity in cell lysates. Stable transformants satisfying the above criteria were subjected to an assay for mitogen-induced DNA synthesis. These transformants exhibited significantly lower DNA synthesis than mock transfection cells on stimulation with basic fibroblast growth factor (bFGF), whereas the two types of cells exhibited similar responses to 10% fetal calf serum and other mitogens, such as epidermal growth factor, 12-O-tetradecanoylphorbol-13-acetate, calcium ionophore A23187, and platelet-derived growth factor. Analysis of the binding of radio-iodinated bFGF to the cells revealed that the transformants did not exhibit a significant decrease in the binding affinity or the number of high affinity sites. These results suggest that the fusion protein specifically inhibits the bFGF signaling not at the binding step but rather at a later step(s) triggered by the binding.

3T3 Cells↗

PubMed1996

Lead nitrate inhibits the induction of CYP1A mRNAs by aromatic amines but not by aryl hydrocarbons in the rat liver.

The effects of lead nitrate on the induction of hepatic cytochrome P450IA (CYP1A) isoforms, mainly CYP1A2, by aromatic amines (2-methoxy-4-aminoazobenzene, 2-amino-3-methyl-9H-pyrido [2,3-b]indole and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine) and aryl hydrocarbons (3-methylcholanthrene, benzo[a]pyrene and beta-naphthoflavone) in male F344 rats were examined at the levels of mRNA, protein and activity of the enzymes. Pretreatment of rats with lead nitrate suppressed the expression of hepatic CYP1A enzyme(s), especially CYP1A2, at both levels of protein and activity of the enzyme(s) by treatment with an aromatic amine or an aryl hydrocarbon. On the other hand, the lead nitrate pretreatment suppressed the induction of CYP1A mRNA(s) by an aromatic amine but not by an aryl hydrocarbon. These findings indicate that lead nitrate suppresses the expression of CYP1A enzymes at both stages of post-translation of mRNAs and transcriptional activation of the genes, and further suggest that the pathway for the transcriptional activation of the CYP1A genes by the aromatic amines is different from that by the aryl hydrocarbons.

Animals↗

PubMed1996

Physical mapping and identification of interspersed homologous sequences in the Trichoplusia ni granulosis virus genome.

A restriction fragment library representing 89.3% of the genome of Trichoplusia ni granulosis virus (TnGV) was constructed. The library consisted of 13 of the 16 BamHI fragments, 18 of the 22 EcoRI fragments, and 6 of the 27 PstI fragments. By restriction endonuclease and Southern blot analysis of cloned or genomic viral DNA fragments, a complete physical map of TnGV was constructed for BamHI, EcoRI, PstI and XhoI. Three interspersed homologous regions (ihs1-ihs3) were identified from hybridization experiments and sequenced. Each TnGV ihs has an approximate size of 400 bp and shows homology to the other two. The orientation of ihs2 is inverted relative to ihs1 and ihs3. TnGV ihs regions do not have repetitive motifs or palindromic sequences, in contrast to homologous regions (hrs) of nuclear polyhedrosis viruses (NPVs). The genomic locations of TnGV ihs1-ihs3, represented in percentage map units, were very similar to those of ihs sequences previously reported in Bombyx mori NPV, suggesting that the ihs may be a novel type of cis-acting element common among baculoviruses. Additionally, an inverted repeat sequence, having overlapping, multiple inverted repeats of 400 bp, was identified to the left of ihs3 on the linearized genome map of TnGV.

Animals↗

PubMed1996

alpha-L-fucosyltransferases from radish primary roots.

A novel alpha-L-fucosyltransferase capable of transferring L-fucose (L-Fuc) from GDP-L-Fuc to the O-2 of alpha-L-arabinofuranosyl residue (GDP-L-Fuc:alpha-L-arabinofuranoside 2-alpha-L-fucosyltransferase) has been found in the microsomal fraction of primary roots from 6-d-old radish (Raphanus sativus L.) seedlings. Enzyme activity was measured fluorometrically at 25 degrees C using a pyridylaminated trisaccharide, L-arabinofuranosylf alpha(1-->3)D-galactopyranosyl beta(1-->6)D-galactose (AraGalGal-PA) as the acceptor. This enzyme found in the microsomal fraction is maximally active at pH 6.8 and requires 0.1% (w/v) Zwittergent 3-16 and 5 mM Mn2+. Chemical and enzymatic analyses of fucosylated AraGalGal-PA confirmed the attachment of L-Fuc to the L-arabinofuranosyl (L-Araf) residue at O-2 by alpha-glycosidic linkage. Radiolabeling was used to assay L-Fuc transfer to L-Araf-containing galacto-oligomers and tamarind xyloglucan. The enzyme specific for the L-Araf residue undergoes development- and organ-specific expression in root tissue, whereas the L-Fuc transfer to tamarind xyloglucan can be detected in microsomal fractions from various organs in developing radish plants. Enzyme assays of membranes fractionated from microsomal fractions revealed that two distinct alpha-L-fucosyltransferases with different acceptor specificity are associated with Golgi membranes from primary roots, whereas hypocotyl Golgi membranes completely lack the enzyme specific for the L-Araf residue.

Carbohydrate Sequence↗

PubMed1996

The relationship between the gene mutation of p53 and the protein expression of p53 and Ki-67 in non-Hodgkin's lymphomas.

The relationship between the mutation of the p53 gene and the expression of the p53 protein and the Ki-67 antigen has been investigated in 115 cases with non-Hodgkin's lymphoma, using the immunohistochemical double staining technique, single-strand conformational polymorphism and DNA sequencing methods. Eighteen cases showed more than 10% of p53+ cells and the others showed a few p53+ cells presented sporadically. Alterations in the p53 gene were detected in six cases with B cell type, consisting of five cases with point mutation and one case with point mutation and 15 base pairs deletion. These six cases showed a high percentage of p53+ cells and five cases revealed that the percentage of p53+ cells was higher than that of Ki-67+ cells (p53+ cells > Ki-67+ cells). Excluding the six cases with mutation of the p53 gene, all cases revealed that the percentage of p53+ cells was less than that of Ki-67+ cells (p53+ cells < Ki-67+ cells). Moreover, there was a positive correlation between expression of the p53 protein and of the Ki-67 antigen in histologic types of B cell lymphomas and of T cell lymphomas, respectively, except in small non-cleaved (Burkitt's) and lymphoblastic types. Therefore, sporadic cases showing p53+ cells > Ki-67+ cells revealed alteration of the p53 gene, and expressed abnormal p53 protein (mutant form). Most cases showing p53+ cells < Ki-67+ cells expressed normal p53 protein (wild type), and may reflect the rapid proliferation rate.

Base Sequence↗

PubMed1996

Positive autoregulation of vipR expression in ViaB region-encoded Vi antigen of Salmonella typhi.

vipR was the first gene in the ViaB region found to be involved in production of the Vi capsular antigen in Salmonella typhi and to be transcribed in the same direction as nine downstream genes. To investigate its function, we constructed a nonpolar vipR mutant by inserting a cat cartridge into the vipR gene on the chromosome. Inactivation of the gene decreased its transcriptional level and the levels of the downstream genes. When a functional vipR gene on a low-copy-number plasmid was introduced into the vipR mutant, the transcriptional levels of the chromosomal genes were restored. These results indicate that the vipR gene product acts as a transcriptional activator for the downstream genes. Interestingly, the vipR gene also was positively regulated by its own product. DNA-binding studies showed that protein extract that contained the VipR product specifically retarded the mobility of a 451-bp BspHI-XbaI fragment upstream of the vipR gene. In addition, complementation analysis indicated that the vipR gene was cotranscribed with a least two downstream genes, vipA and vipB. These findings suggest that the VipR product may interact with the regulatory region upstream of the vipR gene and induce operonic mRNA synthesis that includes the vipR and downstream genes.

Amino Acid Sequence↗

PubMed1996

Retinoic acid receptor beta mediates the growth-inhibitory effect of retinoic acid by promoting apoptosis in human breast cancer cells.

Retinoids are known to inhibit the growth of hormone-dependent but not that of hormone-independent breast cancer cells. We investigated the involvement of retinoic acid (RA) receptors (RARs) in the differential growth-inhibitory effects of retinoids and the underlying mechanism. Our data demonstrate that induction of RAR beta by RA correlates with the growth-inhibitory effect of retinoids. The hormone-independent cells acquired RA sensitivity when the RAR beta expression vector was introduced and expressed in the cells. In addition, RA sensitivity of hormone-dependent cells was inhibited by a RAR beta-selective antagonist and the expression of RAR beta antisense RNA. Introduction of RAR alpha also restored RA sensitivity in hormone-independent cells, but this restoration was accomplished by the induction of endogenous RAR beta expression. Furthermore, we show that induction of apoptosis contributes to the growth-inhibitory effect of RAR beta. Thus, RAR beta can mediate retinoid action in breast cancer cells by promoting apoptosis. Loss of RAR beta, therefore, may contribute to the tumorigenicity of human mammary epithelial cells.

Apoptosis↗

PubMed1996

Polymerase chain reaction of Borrelia burgdorferi flagellin gene in Shulman syndrome.

A 49-year-old man presented a progressive swelling and induration of the skin resulting in flexion contracture. He had a history of two tick bites at the age of 17 and 47 years. Serum anti-Borrelia-burgdorferi antibody was positive; isolation of B. burgdorferi from the skin lesion was unsuccessful. He had eosinophilia (white blood cells 8,300/microlitre, 33% eosinophils) and hypergammaglobulinemia. The diagnosis of Shulman syndrome (eosinophilic fasciitis) from clinical and histological findings was established. A part of the flagellin gene of B. burgdorferi was detected in a skin biopsy sample by using the polymerase chain reaction method. To the best of our knowledge, this is the first report of detection of B.-burgdorferi-specific DNA from a skin sample of Shulman syndrome.

Anti-Inflammatory Agents↗

PubMed1996

Augmentation by phthalimides of phorbol ester-induced expression of tumor necrosis factor alpha message.

N(alpha)-Phthalimidoglutarimide (thalidomide), 2-(2,6-diisopropylphenyl)-1H-isoindole-1,3-dione (PP-33) and its 4,5,6,7-tetrafluoro derivative (FPP-33) augmented 12-O-tetradecanoylphorbol 13-acetate-induced production by human leukemia HL-60 cells of both tumor necrosis factor alpha (TNF-alpha) mRNA and secreted TNF-alpha protein. Intracellular TNF-alpha protein production was increased to a lesser extent.

Blotting, Northern↗