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Biomedical subjects

S Takagi

Publications and source records attributed to S Takagi.

At least 217 records · Page 12Linked to original sources
PubMed1997

Effects of tilisolol, a nonselective beta-adrenergic blocker, on the membrane currents of isolated guinea pig ventricular myocytes.

The effects of tilisolol, a nonselective beta-adrenoceptor blocker, on transmembrane ionic currents were studied in single guinea pig ventricular myocytes by using the whole-cell voltage clamp technique. In the absence of beta-adrenergic stimulation, 10 microM tilisolol, a concentration higher than that used in the clinical therapeutic regimen, did not affect the L-type Ca2+ current (ICa), the inwardly rectifying K+ current (IK1), or the delayed rectifying K+ current (IK). In addition, it did not induce currents through the adenosine triphosphate (ATP)-sensitive K+ channels. However, under the nonselective beta-adrenergic stimulation with 1 microM isoproterenol, 1 microM tilisolol almost completely reversed the agonist-induced increase of IK. The increase of ICa by isoproterenol was blocked only by approximately 30% with tilisolol. We concluded that, at therapeutic concentrations (0.01-0.15 microM), tilisolol is a pure beta-adrenoceptor antagonist that has no direct effects on the transmembrane ionic currents of mammalian ventricular myocytes, such as ICa, IK1, or IK. Comparison of the dose-dependent effects of tilisolol on ICa and IK suggested that tilisolol may selectively inhibit catecholamine-induced increase of IK at the therapeutic concentrations. The virtually selective inhibition of IK, leaving ICa intact, may be favorable to prevent the catecholamine-induced arrhythmia without inhibiting contraction.

Adrenergic beta-Antagonists↗
PubMed1997

Effect of a two-solution fluoride mouth rinse on deposition of loosely bound fluoride on sound root tissue and remineralization of root lesions in vitro.

A constant-composition fluoride (F) titration method was used to measure the amount of leachable F deposited on root surfaces in vitro by a 1-min rinse with a 12 mmol/l sodium fluoride (228 micrograms/g F) solution or a two-solution rinse that contained 2 mmol/l sodium fluorosilicate (228 micrograms/g total F ) and 10 mmol/l calcium chloride. The mean +/- standard deviations (n = 3) F uptake from the two rinse treatments were 0.70 +/- 0.24 micrograms/cm2 and 3.25 +/- 0.74 micrograms/cm2, respectively. In a separate experiment, the effects of sodium fluoride and the two-solution rinses on remineralization of root lesions were evaluated in an in vitro pH cycling model. The results showed that the average decrease in mineral loss (delta Z) in the two-solution rinse group (60%) was significantly greater than that obtained in the NaF rinse (41%) or the control (9%) group.

Aluminum Compounds↗
PubMed1997

Cellular and axonal migrations are misguided along both body axes in the maternal-effect mau-2 mutants of Caenorhabditis elegans.

We have characterized the mau-2 mutants of Caenorhabditis elegans and found that migrating cells and axons are mispositioned along both the antero-posterior and dorsoventral body axes. This is in contrast to previously characterized guidance mutations in Caenorhabditis and in Drosophila, which have been found to be axis-specific. Two observations suggest that mau-2 acts very early during development: most behavioral phenotypes of mau-2 can be rescued by a maternal effect, and variations in expressivity involve an entire body side at a time. The possibility that mau-2 is involved in the spatial organization of guidance cues encoded by other genes is discussed.

Animals↗
PubMed1997

Structural analysis of N-glycans of storage glycoproteins in soybean (Glycine max. L) seed.

The structures of N-linked sugar chains (N-glycans) of storage glycoproteins in soybean seeds have been identified. Eight pyridylaminated (PA-) N-linked sugar chains were derived and purified from hydrazinolysates of the storage glycoproteins by reverse-phase HPLC and size-fractionation HPLC. The structures of the PA-sugar chains purified were first identified by two-dimensional PA-sugar chain mapping and ion-spray mass analysis, considering the results of sugar composition analysis or sequential exoglycosidase digestion. The deduced structures were further analyzed by ion-spray tandem mass spectrometry and 500 MHz 1H-NMR spectrometry. The eight structures fell into two categories; the major class (96.6%) was a typical high mannose-type, the minor class was a xylose containing-type (Man3Xyl1GlcNac2, Man3Fuc1Xyl1GlcNac2; 3.4%).

Carbohydrate Sequence↗
PubMed1997

A comparative study of high-fat diet containing fish oil or lard on blood glucose in genetically diabetic (db/db) mice.

The effects of high-fat diets containing fish oil or lard on blood glucose and plasma insulin after oral glucose loading were compared in genetically diabetic (db/db) mice, one of the animal models of non-insulin-dependent diabetes mellitus (NIDDM) with hyperinsulinemia. The blood glucose levels were significantly decreased in 27% of the mice fed high-fat diets containing 20% fish oil 30 and 60 min after the oral administration of glucose (both; p < 0.05). Conversely, the plasma insulin levels were significantly increased 30 min after the glucose loading as compared to 27% of the mice fed high-fat diets containing 20% lard (p < 0.01). In addition, a significant hypoglycemic effect was observed 60 min after the subcutaneous administration of insulin to mice on the fish oil diet (p < 0.05), whereas no effect was demonstrated in the case of those on the lard diet. The average body weight of the fish oil-treated mice was not significantly different from that of the lard-treated mice. The fish oil diet has a beneficial effect on glucose tolerance by increasing the insulin secretory capacity from pancreatic beta cells and also ameliorating insulin resistance.

Animals↗
PubMed1997

[Pupillary abnormalities in a patient with clinically diagnosed corticobasal degeneration].

We report a 65-year-old woman, who suffered from clumsiness of the left hand for 6 years. Gait disturbance, body balance impairment and rigidity of the left arm appeared progressively. Anti-parkinsonian drugs such as 1-dopa, doroxidopa, amantadine and bromocriptine were ineffective. Magnetic resonance imaging showed brain atrophy, especially in the right fronto-parietal lobes. Positron emission tomography (18F-fluoro-2-deoxy-D-glucose) showed decreased glucose metabolism in the right cerebral cortex, putamen and thalamus. A diagnosis of corticobasal degeneration was made, based on the clinical manifestations, MRI and PET findings. She also showed anisocoria, vertical gaze palsy and abnormal pupillary reactions. Her left pupil showed an oval figure shifted from the center position. The pupils exhibited denervation supersensitivity in the 0.125% pilocarpine test. We consider that her pupillary abnormalities may be related to her midbrain lesion (midbrain corectopia) associated with corticobasal degeneration.

Aged↗
PubMed1996

Anti-cancer agent OK432 induces manganese superoxide dismutase in human granulocytes.

Manganese superoxide dismutase (MnSOD) is a mitochondrial enzyme involved in scavenging O2-. OK432, a Streptococcal preparation, has anti-tumor activity and is also known to be a biological-response modifier. In this study, we have examined the regulation of MnSOD gene by OK432 in human granulocytes. Granulocytes had a low activity of MnSOD; OK432 increased MnSOD mRNA levels in a dose-dependent manner and its activity in granulocytes. OK432 also induced the MnSOD mRNA in HL60 promyelocytes, while not affecting the levels of MnSOD mRNA in human fibroblasts. Pre-treatment with either actinomycin D or cycloheximide inhibited the induction of MnSOD mRNA by OK432. OK432 increased the levels of interleukin-1 (IL-1) and tumor-necrosis-factor-alpha (TNFalpha) mRNA in granulocytes. Furthermore, the induction of MnSOD mRNA by OK432 was blocked by anti-IL-1 antibody but not by anti-TNF antibody. These results suggest that the induction of MnSOD mRNA by OK432 is regulated at the transcriptional level, and OK432 induces MnSOD mRNA, at least in part, through production of IL-1 in granulocytes.

Antibodies↗
PubMed1996

Structure and expression of two highly related genes encoding SCM-1/human lymphotactin.

SCM-1/lymphotactin is a chemokine-like molecule produced selectively, if not exclusively, by activated CD8+ T cells. Here we report that there are two highly homologous SCM-1 genes, which we designate as SCM-1alpha and SCM-1beta. Both genes have three exons and two introns. The 1st intron of SCM-1alpha contains a pseudogene of the ribosomal large subunit L7a. In SCM-1beta, a 1.5-kb region including about a quarter of the L7a pseudogene is deleted from the 1st intron. Otherwise, the two genes are highly homologous including the 5' and 3' flanking regions. Both genes were mapped to human chromosome 1q23. The two genes were similarly induced in peripheral blood mononuclear cells by mitogenic stimulation. Primer extension and RNase protection revealed several transcription initiation sites. The biological activities of SCM-1alpha and SCM-1beta, which have two amino acid differences at positions 7 and 8 in the mature proteins, remain to be compared.

Amino Acid Sequence↗
PubMed1996

Mutagenicity of 24-hour duplicate of Japanese diet.

In order to elucidate the genotoxicological characteristics of the Japanese diet, the mutagenicity of 24-h duplicate of the diet samples were investigated. The mutagenicity of blue rayon extract was examined in the Ames Salmonella/microsome assay. Thirty-two (91.4%) of 35 samples revealed mutagenicity toward Salmonella typhimurium TA98 in the presence of S9 mix. The mutagenic activities showed significant correlations with the consumption rates of broiled fish (r = 0.517, p = 0.0021) and broiled meat (r = 0.494, p = 0.0036). In other test conditions, 6 (17.1%), 5 (14.3%) and 8 (22.9%) samples were mutagenic to Salmonella typhimurium TA98 without S9 mix, TA100 with S9 mix and TA100 without S9 mix, respectively. Findings in the present study suggest that high consumption of broiled fish and broiled meat are important as the source of mutagens/carcinogens in the Japanese diet. In the present study, however, biological inference of these findings could not be made in relation to the occurrence of cancers, especially of the gastric cancer, which is the most prevalent form of cancer in Japan.

Aged↗