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Biomedical subjects

Y Kasai

Publications and source records attributed to Y Kasai.

At least 91 records · Page 5Linked to original sources
PubMed1995

[General pharmacological study of iodixanol, a new non-ionic isotonic contrast medium].

The general pharmacological study of iodixanol, a non-ionic isotonic contrast medium, was conducted. 1) Iodixanol administered intravenously over a dose range of 320 to 3,200 mgI/kg had little or no effect on the general behavior, spontaneous locomotor activity, hexobarbital sleeping time, pain response, electroshock- or pentylenetetrazol-induced convulsion (mouse), EEG or body temperature (rabbit), gastrointestinal propulsion (mouse) or skeletal muscle contraction (rabbit). Iodixanol had no specific interaction with acetylcholine, histamine, serotonin, nicotin, BaCl2 (ileum), methacholine (trachea), isoprenaline (atrium) or oxytocin (pregnant uterus), nor had any effect on spontaneous contractility (atrium and uterus), or transmural electrostimulation-induced contractility (vas deferens) at concentrations of < or = 3.2 x 10(-3) gI/ml in vitro. Iodixanol had no effect on the cardiovascular system of dog, except that it increased femoral blood flow and respiratory rate at doses of > or = 1,000 mgI/kg. Iodixanol at 3,200 mgI/kg i.v. reduced urine output with a decrease in Na+ and Cl- excretion, whereas at 320 mgI/kg i.v., it slightly increased urine output (rat). 2) Injections of iodixanol into the cerebroventricular (0.96, 9.6 mgI/mouse and 3.2, 32 mgI/rat), left ventricular (1,920, 6,400 mgI/dog) or coronary artery (640, 1,920 mgI/dog) had no conspicuous effect on the central nervous system or the cardiovascular system, respectively. There was no marked difference among iodixanol, iohexol and iopamidol in this respect. Vascular pain during injection into the femoral artery (300-320 mgI/guinea pig) appeared to be less intense with iodixanol, compared with the other contrast media iohexol and iopamidol. These results suggest that intravenous injection of iodixanol is relatively free from pharmacological activity, and effects of iodixanol on the central nervous system (intracerebroventricular injection) and cardiovascular system (intra-left ventricular and -coronary injections) are comparable to those of iohexol and iopamidol. Furthermore, intra-femoral injection of iodixanol has less of a tendency to produce vascular pain than those of iohexol and iopamidol.

Animals↗
PubMed1995

[A synchronous double cancer of esophagus and stomach treated with 5-fluorouracil and consecutive low-dose cisplatin].

We report a case of double cancer of esophagus and stomach treated with 5-fluorouracil and consecutive low-dose cisplatin. The patient was a 58-year-old man with liver cirrhosis. Using upper gastrointestinal fiberscopy, a superficial depressed lesion (O-IIc) in the middle thoracic part of the esophagus and Borrmann 2 type lesion in the fundus of the stomach were also detected. Microscopic examination of the biopsy specimen revealed moderately differentiated squamous cell carcinoma and adenocarcinoma. But laparotomy could not be done due to impaired liver function (KICG 0.051, ICGR15 45.2%). The patient was treated for 28 days with continuous 24 hour infusion 5-FU, 250 mg/body/day plus low dose CD-DP, 10 mg/body daily by bolus infusion d1-5, 8-12, 15-19, 22-26. One month after the chemotherapy, both the gastric cancer and the esophageal cancer were remarkably reduced (diagnosis: PR), and showed no malignancy in the histology. There was no change in the histological findings of the esophageal lesion at 31 months after the chemotherapy. This therapy is effective for patients with gastric cancer and esophageal cancer.

Adenocarcinoma↗
PubMed1995

[Epidemiological study of osteoporosis].

An epidemiological investigation of osteoporosis was carried out in a community in which fishing is the primary industry, and correlations were investigated between the bone mass and various risk factors for osteoporosis and biochemical findings. In 852, who could be examined directly, of the 3541 males and females aged 40 years or above living in Nansei Town, Watarai District, Mie Prefecture, the age, sex, height, body weight, years after menopause, married or unmarried, area of residence, daily activity, and intakes of milk, fish, and alcohol were studied by direct oral inquiry, and the serum calcium, inorganic phosphorus, alkaline phosphatase, and total protein were measured. The subjects were divided into a decreased bone mass group who showed grade I or more advanced loss in bone mass and a normal bone mass group who showed no or only slight loss in bone mass on the basis of microdensitometry (MD). Eighty-two subjects (9.6%) were classified as the decreased bone mass group. Items that showed a close correlation with sigma GS/D, which is an index of bone density, were age, years after menopause, serum alkaline phosphatase level, height, and body weight in females, age and serum alkaline phosphatase level in males. In the decreased bone mass group, 79 of the 82 subjects were females. Significant differences were observed between the decreased bone mass group and the normal bone mass group in age, years after menopause, serum alkaline phosphatase level, height, and body weight. From these results, a high age, being a female, low height, and a low body weight were found to be factors correlated with osteoporosis. Also, the bone mass was correlated with the serum alkaline phosphatase level and years after menopause.

Adult↗
PubMed1994

Effects of cyclopiazonic acid on rhythmic contractions in uterine smooth muscle bundles of the rat.

1. We studied the effects of cyclopiazonic acid (CPA) on rhythmic contractions and on Ca2+ uptake by the intracellular stores in longitudinal muscle strips of the rat uterus at 30 degrees C. 2. Oxytocin (1 microM) in Ca(2+)-free solution induced a transient rise in the intracellular Ca2+ concentration ([Ca2+]i) and contraction after Ca2+ loading of the stores in high-K(+)- and Ca(2+)-containing solution. CPA inhibited oxytocin-induced Ca2+ release and contraction, the half and full inhibitory concentrations of CPA being 0.3 and 10 microM, respectively. In contrast, addition of CPA after Ca2+ loading exerted no significant inhibitory effects. 3. Oxytocin (10 nM) applied in Ca(2+)-containing solution induced rhythmic increases in both force and [Ca2+]i. CPA (10 microM) had no effect on oxytocin-induced rhythmic contractions. 4. At a high concentration (300 microM), CPA inhibited the rhythmic contractions induced by 10 nM oxytocin; the frequency and the peak height were decreased, and in many bundles contractions were completely abolished. These inhibitory effects were reversed after CPA washout. 5. CPA (300 microM) inhibited the rate of rise of [Ca2+]i due to depolarization induced by high-K(+)-containing solution. 6. These results suggest that low concentrations of CPA inhibit the loading of Ca2+ into intracellular stores in intact tissue strips, and that the Ca2+ stores are not directly involved in the uterine rhythmic contractions. It is also suggested that a high concentration of CPA inhibits the mechanism that is responsible for the generation of rhythmic contractions as well as voltage-dependent Ca2+ channels.

Animals↗
PubMed1994

Control of CNS midline transcription by asymmetric E-box-like elements: similarity to xenobiotic responsive regulation.

Central nervous system midline cells constitute a discrete group of Drosophila embryonic cells with numerous functional and developmental roles. Corresponding to their separate identity, the midline cells display patterns of gene expression distinct from the lateral central nervous system. A conserved 5 base pair sequence (ACGTG) was identified in central nervous system midline transcriptional enhancers of three genes. Germ-line transformation experiments indicate that this motif forms the core of an element required for central nervous system midline transcription. The central nervous system midline element is related to the mammalian xenobiotic response element, which regulates transcription of genes that metabolize aromatic hydrocarbons. These data suggest a model whereby related basic-helix-loop-helix-PAS proteins interact with asymmetric E-box-like target sequences to control these disparate processes.

Animals↗
PubMed1994

General pharmacological profile of the new cognition-enhancing agent nefiracetam.

The general pharmacological properties of a novel cognition-enhancing agent, nefiracetam (N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl)acetamide, DM-9384, CAS 77191-36-7) were investigated, and the following results were obtained. 1. Central nervous system: Nefiracetam showed depressant activities (such as ataxia) on general behavior (mice), and inhibited spontaneous locomotor activity, rota-rod and traction performances (mice) and polysynaptic potential of the spinal reflex (rats), and potentiated pentobarbital anesthesia (mice). The drug inhibited electroshock-induced seizure at relatively low doses, but did not affect chemoshock-induced seizure (mice). Nefiracetam failed to show analgesic activity in the tail pinch test, but inhibited the acetic acid-induced writhing syndrome (mice). An inhibitory pattern in the electroencephalogram was observed (cats). Nefiracetam had little or no effect on body temperature (rats). 2. Respiratory and cardiovascular systems: Nefiracetam induced transient decreases in blood pressure, left ventricular pressure and LV dp/dt max at higher doses (dogs). 3. Autonomic nervous system: Nefiracetam had no influence on pupil size (rabbits). The drug induced no significant effect on the pressor response to norepinephrine or depressor response to acetylcholine, but inhibited the contractile response of the nictitating membrane to preganglionic cervical sympathetic nerve stimulation at the highest dose (dogs). 4. Gastrointestinal system: Nefiracetam inhibited gastrointestinal propulsion (mice), gastric emptying rate and gastric secretion (rats) at higher doses. Nefiracetam produced no apparent damage in the gastric mucosa, and had no effect on bile secretion (rats). 5. Isolated smooth muscle: Nefiracetam had no effect on the resting tonus of isolated ileum, whereas it inhibited the contractile response to acetylcholine, histamine, serotonin, nicotine and BaCl2 at higher concentrations (guinea pigs). Nefiracetam had no effect on the resting tonus or the serotonin-induced contraction of stomach fundus (rats). The drug had no effect on the resting tonus or the norepinephrine-induced contraction of vas deferens, but tended to inhibit the contraction induced by nerve stimulation (guinea pigs). Nefiracetam had little or no effect on the resting tonus or oxytocin-induced contraction of virgin uterus, or on spontaneous contraction of pregnant uterus (rats). Nefiracetam did not affect the resting tonus of trachea, whereas it inhibited isoproterenol-induced relaxation at the highest concentration (guinea pigs). Nefiracetam had no chronotropic effect in isolated atria, but showed a slight negative inotropic effect at the highest concentration (guinea pigs). 6. Miscellaneous: Nefiracetam slightly decreased urinary volume, whereas it did not affect urinary electrolyte excretion (rats).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

Aphidicolin potentiates apoptosis induced by arabinosyl nucleosides in human myeloid leukemia cell lines.

We investigated the effect of aphidicolin, an inhibitor of DNA polymerase alpha and delta, on the induction of apoptosis by arabinosyl nucleosides in a human promyelocytic leukemia cell line, HL-60. Pretreatment of HL-60 cells with aphidicolin (2 microM) significantly increased the number of morphologically apoptotic cells induced by 1-beta-D arabinofuranosylcytosine (ara-C) during 4 hr of incubation. This is consistent with the appearance of DNA fragmentation as determined quantitatively by diphenylamine or by agarose gel electrophoresis. The inhibition of cell growth on day 3 after drug exposure was correlated with the degree of apoptosis: Such synergistic interaction between aphidicolin and ara-C has also been observed in other human myeloid leukemia cell lines, U937 and KG-1. In addition, the induction of apoptosis by 9-beta-D arabinofuranosyladenine or 9-beta-D arabinofuranosylguanine is augmented by aphidicolin.

Aphidicolin↗
PubMed1993

Immortalization of normal human salivary gland cells with duct-, myoepithelial-, acinar-, or squamous phenotype by transfection with SV40 ori- mutant deoxyribonucleic acid.

BACKGROUND: Based on morphologic and functional differences mainly, 4 distinct types of cells are recognized in human salivary glands. For a better understanding of cellular proliferation and differentiation of human salivary glands as well as carcinogenesis of salivary gland neoplasms, we attempted to establish normal human salivary gland cells in an in vitro system. EXPERIMENTAL DESIGN: Primary cultured human salivary gland cells were transfected with origin-defective mutant DNA of SV40. After 2 to 3 weeks of transfection, slowly expanding colonies consisting of small compact cells emerged, whereas mock-transfected cells did not grow any more and eventually entered crisis, followed by cell death. RESULTS: Using limited dilution technique, we isolated 4 cell clones with distinct morphology from a single colony. Morphologic observation of cells cultured on plastic dishes precisely revealed the characteristics of constituent cells of salivary glands; i.e., three cell clones showing cuboidal (NS-SV-DC), spindle (NS-SV-MC), and flattened (NS-SV-SC) morphology were similar to duct, myoepithelial, and squamous cells, respectively. A remaining cell clone showing polygonal in shape with numerous secretory granules (NS-SV-AC) resembled acinar cells. Characterization of cell clones by the ultrastructural examination and the search for specific antigens showed the similarity of NS-SV-DC, NS-SV-MC, NS-SV-AC, and NS-SV-SC to duct, myoepithelial, acinar, and squamous cells, respectively. Integration and expression of SV40 DNA were confirmed by Southern blot and indirect immunofluorescence staining. Anchorage-independent growth in soft-agar and tumorigenicity in nude mice were not recognized in all cell clones. CONCLUSIONS: These results demonstrate that establishment of cell clones with duct-, myoepithelial-, acinar-, or squamous phenotype was accomplished in the in vitro system, and that based on the evaluation of colony-forming ability in soft-agar and tumorigenicity in nude mice, these cell clones are considered to be non-neoplastic.

Animals↗
PubMed1993

General pharmacological profile of the new anti-ulcer drug 3-[[[2-(3,4-dimethoxyphenyl)ethyl]carbamoyl]methyl]-amino-N -methylbenzamide.

Pharmacological properties of the anti-ulcer drug 3-[[[2-(3,4-dimethoxyphenyl)ethyl]carbamoyl] methyl]-amino-N-methylbenzamide (DQ-2511, CAS 104775-36-2) on the central and autonomic nervous systems, smooth muscle, gastrointestinal system, and other miscellaneous systems were investigated. 1. DQ-2511 showed little or no influence on general behavior, spontaneous motor activity, hexobarbital sleeping time (mouse), conditioned avoidance response (rat), body temperature (rabbit), EEG or spinal reflex (cat) after oral administration (300-1000 mg/kg) or intravenous injection (15, 50 mg/kg). It also had no anticonvulsant or analgesic activities (mouse). 2. DQ-2511 had no influence on pupil size (rabbit). It reduced or tended to reduce contractile responses of the nictitating membrane induced by electrical stimulation of pre- and post-ganglionic sympathetic nerve (cat) at the highest dose. The drug inhibited the pressor response to norepinephrine, but had little or no inhibitory effect on the depressor response to acetylcholine at the highest dose (dog). 3. DQ-2511 reduced contractile responses to nicotine, BaCl2, acetylcholine, histamine and serotonin (isolated guinea pig ileum), to acetylcholine and histamine (trachea), and to norepinephrine (vas deferens) at high concentrations. It also inhibited spontaneous and oxytocin-induced motility (isolated rat uterus). 4. DQ-2511 decreased gastric motility in a dose-related manner at intravenous doses of 5-50 mg/kg (dog). It also reduced gastric emptying rate at oral doses of 100-1000 mg/kg, and gastric secretion at intraperitoneal doses of 100-300 mg/kg (rat). On the other hand, it induced no definite changes in intestinal motility (dog) or gastrointestinal transit (mouse).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Enzyme immunoassay of liver-type arginase and its potential clinical application.

We developed an efficient enzyme-linked immunosorbent assay (ELISA) system for measurement of human liver-type arginase in serum. A conjugate of the Fab' fragment of anti-human liver (recombinant) arginase IgG and horseradish peroxidase was used as the second antibody. This assay is highly specific, sensitive, and reproducible, enabling us to detect arginase at concentrations as low as several micrograms per liter without any prior processing of serum. The reaction is linear up to 200 micrograms/L. The arginase concentration in serum, as determined by this method, increased markedly and temporarily at the time of surgical operation or later injury to the liver. The increase was accompanied or followed by increases in serum concentrations of aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase, suggesting that the arginase emerged from damaged hepatocytes. In view of a limited tissue distribution of liver-type arginase, our ELISA system may be useful in diagnosis of various hepatic disorders as well as follow-up of postoperative conditions of patients.

Adolescent↗
PubMed1992

Molecular cloning of murine monoclonal anti-idiotypic Fab.

Anti-idiotypic antibodies (Ab2) binding to idiotopes on antibodies with various antigen binding specificities (Ab1) are potential regulators of immunity in a variety of diseases, such as autoimmunity, cancer, and viral, bacterial, or parasitic infections. Furthermore, Ab2 are useful probes for the characterization of receptor/ligand interactions. Thus far, Ab2 production has been limited to the isolation of polyclonal Ab2 from immune sera or monoclonal Ab2 from hybridoma supernatants. However, both approaches have produced a limited number of Ab2. As an alternative approach, we demonstrate here the production of Ab2-Fab by using repertoire cloning. Using HIV-1 as a model system, the Ab2-Fab were generated from the spleens of mice immunized with the virus-neutralizing and syncytia-inhibiting anti-HIV-1 monoclonal antibody 0.5 beta. A bacteriophage lambda vector system was used to express a combinatorial library in Escherichia coli. Iodinated 0.5 beta was used to identify 17 Ab2-Fab clones. DNA sequence analysis of five clones revealed three similar kappa and Fd combinations. The Ab2-Fab bound with high affinity (3.5-6.5 x 10(9) liters/mol) specifically to the Ab1 and not to isotype-matched antibodies with unrelated specificities. The three Ab2-Fab probably bind to the same idiotope on the Ab1 as demonstrated in cross-competition binding studies. The Ab2-Fab inhibited binding of the Ab1 to antigen, and therefore, may functionally mimic the epitope defined by the Ab1. Repertoire cloning of Ab2-Fab may facilitate the generation of Ab2 that have potential as modulators of immune responses against various antigens.

Amino Acid Sequence↗
PubMed1992

Involvement of p53 mutation in the development of human salivary gland pleomorphic adenomas.

We examined the status of the p53 mutation, a putative tumor suppressor gene, as well as the expressions of myc and mos oncogene products in human salivary gland pleomorphic adenoma cells in culture derived from four individuals using techniques which enabled selective and favourable growths of tumor cells. Culture techniques empolyed in this study consisted of type I collagen gel-coated dishes and serum-free medium as substrates and growth medium, respectively. Cells grown under above conditions were subjected to the analyses of p53, myc and mos expression. When analyzed by both immunocytochemical staining and immunoblot, mutant forms of p53 specifically detected by PAb240 were observed in three of 4 cases. However, none of the 4 cases expressed myc and mos oncogene products. These results may imply a role for p53 mutation in the development of human salivary gland pleomorphic adenomas.

Adenoma, Pleomorphic↗
PubMed1992

Dorsal-ventral patterning in Drosophila: DNA binding of snail protein to the single-minded gene.

The Drosophila snail gene is required for proper mesodermal development. Genetic studies suggest that it functions by repressing adjacent ectodermal gene expression including that of the single-minded (sim) gene. The snail gene encodes a protein with a zinc-finger motif, and here we report that the snail gene product is a sequence-specific DNA binding protein. The snail protein recognizes a 14-base-pair consensus sequence that is found nine times in a 2.8-kilobase sim regulatory region. These results provide evidence for the direct control of sim transcription by snail.

Adenovirus Early Proteins↗
PubMed1992

Pre-treatment of a human T-lymphoblastoid cell line with L-asparaginase reduces etoposide-induced DNA strand breakage and cytotoxicity.

The effect of L-asparaginase (L-asp) pre-treatment on etoposide-induced DNA strand breakage and cytotoxicity was investigated. In a T-lymphoblastoid cell line, Molt 4, etoposide-induced DNA strand breaks, DNA-protein cross-links and cytotoxicity were reduced by pre-treatment with L-asp for 15 hr, but it did not cause these changes in a promyelocytic-leukemia cell line, HL-60, which is less sensitive than Molt 4 to L-asp. However, pre-treatment of Molt 4 cells with L-asp did not significantly alter the accumulation of [3H]-etoposide. Cell-cycle analyses showed an increase in G1-phase cells, a significant decrease in both S-phase cells and G2/M-phase cells pre-treated with L-asp in Molt 4 cells, but L-asp exposure did not result in any significant changes in HL-60 cells. On the other hand, L-asp pre-treatment did not affect topoisomerase-I (Topo-I) inhibitor, camptothecin (CPT)-induced DNA strand breaks or toxicity in Molt 4 cells. Our data imply that a decrease in S- and G2/M-phase cells following L-asp treatment may explain the reduction of etoposide-induced DNA lesions and cytotoxicity in Molt 4 cells, since topoisomerase-II (Topo-II) content or activity is a function of cellular proliferation status.

Asparaginase↗