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Biomedical subjects

S Katayama

Publications and source records attributed to S Katayama.

At least 379 records · Page 21Linked to original sources
PubMed1988

Effects of cyclosporin A and insulin on peripheral lymphocytes in BB/W rats.

The effects of cyclosporin A (Cs-A) and insulin on peripheral lymphocytes in BB/W rats were studied. The cumulative incidence of overt diabetes in untreated BB/W rats was 72% up to 120 days of observation, whereas the incidence was 13% in Cs-A-treated rats. Lymphocytopenia, consisting of decreased OX19+ (pan T), W3/25+ (helper/inducer T) and OX8+ (cytotoxic/suppressor T) cells, was present in BB/W rats. Cs-A significantly decreased both the percentage and the absolute number of OX8+, OX6+ (Ia-positive) and OX12+ (B) cells, and augmented the ratio of W3/25+ to OX8+ cells in BB/W rats. On the other hand, insulin injection significantly decreased the percentage of OX6+ cells and the ratio of W3/25+ to OX8+ cells in BB/W rats. Thus, rearrangement of the ratio of helper/inducer T to cytotoxic/suppressor T cells and reduction in the number of Ia antigen-bearing cells could be important for the inhibitory effects of diabetes in BB/W rats upon treatment with Cs-A or insulin.

Animals↗
PubMed1987

Effects of calcium antagonists on muscarinic receptor subtypes in the rat brain.

The effects of several calcium antagonists, including nicardipine, nifedipine, verapamil, and diltiazem, on muscarinic acetylcholine antagonist binding were studied in the P2 fraction of the rat cerebral cortex using either [3H]quinuclidinyl benzilate ([3H]QNB) or [3H]pirenzipine as the radioactive ligand. (1) The potency of [3H]QNB binding inhibition was in the order nicardipine greater than verapamil greater than diltiazem greater than nifedipine. The IC50 values of nicardipine, verapamil, and diltiazem were 2.56 X 10(-6) M, 1.28 X 10(-5) M, and 6.00 X 10(-5) M, respectively. (2) The inhibition of [3H]QNB binding by nicardipine was significantly decreased in the presence of Ca ions. (3) In saturation experiments of [3H]QNB binding in the presence of nicardipine, the Kd value appeared to be significantly affected, but the Bmax value was unchanged. This indicated that nicardipine probably inhibited [3H]QNB binding allosterically. On the other hand, (4) nicardipine inhibited [3H]pirenzipine binding completely with an IC50 value of 7.87 X 10(-7) M. It was concluded that nicardipine had an inhibitory effect on M1-receptor binding.

Animals↗
PubMed1987

[Pathological characteristics of the thyroid gland in patients with triiodothyronine-predominant Graves' disease].

Pathology of the thyroid gland tissue was characterized in patients with Triiodothyronine (T3)-predominant Graves' disease who had normal levels of serum T4 but increased levels of serum T3 during antithyroid drug therapy. In order to compare this group of patients with an usual type of Graves' patients, age, sex, dietary intake of iodide, duration of antithyroid therapy and the dose of thionamide drugs were matched between the two groups of patients. Thyroid tissue was obtained from subtotal thyroidectomy. In examining the histology of the thyroid gland, integration eye piece plate II with regularly arranged 100 lattice points was set on eye lens of a microscope. The number of crossing points which were projected on each 4 histological elements was counted in randomly selected 10 fields of vision in each patient's thyroid. Assuming that the every histological element is arranged in a random manner, errors of each visual field by this method would be less than 12%. In consequence, the significant difference was demonstrated in the weight of subtotally resected thyroid and the ratio of each histological element except interstitial tissue occupied in the total thyroid tissue between T3-predominant Graves' disease and control Graves' disease. The volume composition of the epithelial cells and vacuoles in patients with T3-predominant Graves' disease was significantly greater than that of patients with control Graves' disease (24.7 +/- 10.6 vs 14.4 +/- 6.5%, 5.9 +/- 3.9 vs 2.0 +/- 1.0%, Mean +/- SD, respectively, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Graves Disease↗
PubMed1987

Thyroid carcinoma and hot nodule.

A 70-year-old woman presented with a nodule in the thyroid gland. 131I scintigraphy of the gland showed a hot nodule. Histology of the resected thyroid revealed a papillary adenocarcinoma. Although a thyroid carcinoma with a hot nodule seen on the radioiodine isotope scan is a very rare occurrence, it is clinically very important because it may indicate a thyroid malignancy.

Adenocarcinoma, Papillary↗
PubMed1987

Ultrastructural study of poorly differentiated medullary carcinoma of the thyroid.

Five cases of sporadic medullary carcinoma of the thyroid (MTC) with rapidly progressive disease were studied ultrastructurally. The tumour cells had poorly differentiated C cell characteristics. They exhibited smaller secretory granules in their narrow cytoplasm. Morphometric analysis disclosed that the average diameter of the secretory granules of the cases with a poor prognosis was 173.0 nm in comparison with 254.2 nm of well differentiated cases. The granules were fewer in the poor prognostic group (1.31/mu 2) than the well differentiated group (2.75/mu 2). Increased free ribosomes and polysomes were noted in the cytoplasm and dispersed chromatin in the nuclei. These cases should be therefore classified as poorly differentiated MTC rather than atypical or anaplastic MTC.

Adult↗
PubMed1987

6-Methyl-1,2,4-benzenetriol, a new intermediate in penicillic acid biosynthesis in Penicillium cyclopium.

Penicillic acid-negative mutants were obtained from a color mutant derived from Penicillium cyclopium NRRL 1888 through N-methyl-N'-nitro-N-nitrosoguanidine treatment. One mutant (SK2N6) accumulated 6-methyl-1,2,4-benzenetriol, which was not previously known to be a metabolite of P. cyclopium, in addition to orsellinic acid and orcinol. The radioactivity of [1-14C]acetic acid was rapidly incorporated into 6-methyl-1,2,4-benzenetriol in a culture of P. cyclopium SK2N6. Moreover, the radioactivity of [14C]6-methyl-1,2,4-benzenetriol was efficiently incorporated into penicillic acid in a culture of P. cyclopium NRRL 1888. These data indicate that 6-methyl-1,2,4-benzenetriol is a precursor for penicillic acid biosynthesis. The results on the addition of 1,4-dihydroxy-6-methoxy-2-methylbenzene, 6-methoxy-2-methylbenzoquinone(1,4), and 1-O-methylorcinol to a culture of P. cyclopium SK2N6 indicated that only the former two compounds are converted to penicillic acid. Thus, a new portion of the penicillic acid biosynthetic pathway is proposed.

Caproates↗
PubMed1987

Effect of azelastine on the release and action of leukotriene C4 and D4.

The effect of azelastine on the release of leukotriene C4 and D4 (LTC4 and LTD4), and the antagonistic action of the drug against the leukotrienes were determined by using in vitro tests and compared with those of ketotifen and chlorpheniramine. Azelastine inhibited LTC4 and LTD4 release from guinea pig lung fragments passively sensitized with homologous anti-ovalbumin IgGl-b antibody. The 50% inhibitory concentration (IC50) of azelastine was 6.4 X 10(-5) M for a 15-min preincubation or 4.7 X 10(-5) M for a 30-min preincubation. Ketotifen and chlorpheniramine were inhibitory only at the highest concentration tested (3 X 10(-4) M), giving inhibitions of 35.6 and 21.3%, respectively. Azelastine also inhibited calcium ionophore A23187-induced release of leukotrienes from human polymorphonuclear leukocytes; the IC50 values were 3.6 X 10(-5) M for 15 min and 2.3 X 10(-6) M for 30 min of preincubation. Ketotifen and chlorpheniramine were inhibitory only after a 30-min preincubation, with IC50 values of 2.1 X 10(-5) and 5.9 X 10(-5) M, respectively. The potent inhibition by azelastine might be partly a result of the inhibition of 5-lipoxygenase, since 5-hydroxyeicosatetraenoic acid formation in rat basophilic leukemia cell homogenate was inhibited by azelastine. Pretreatment of guinea pig ileum with azelastine antagonized LTC4- and LTD4-induced contraction of the ileum with IC50 values of 7.0 X 10(-6) and 1.1 X 10(-5) M, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Treatment of phenylketonuria with a formula consisting of low-phenylalanine peptide. A collaborative study.

A method of preparation of a more palatable therapeutic formula for phenylketonuria (PKU), consisting of low-phenylalanine peptide (LPP), was reported. There were no adverse effects and, in fact, there was a reduced frequency of diarrhea in patients who received LPP formula for more than 6 months. The LPP formula can be used not only as a more palatable therapeutic milk for PKU, but also as an ingredient to make more palatable foods of low-phenylalanine content.

Adolescent↗
PubMed1987

Serum dehydroepiandrosterone sulfate concentrations in secondary adrenal insufficiency.

Serum dehydroepiandrosterone sulfate (DHEA-S) concentrations were studied in 84 untreated patients with secondary adrenal insufficiency. Compared to values in normal subjects of corresponding age, DHEA-S levels were decreased in 80 patients. The decrease was unrelated to the cause of the secondary adrenal insufficiency or the serum PRL level. Serum cortisol concentrations, on the other hand, were low in 71 patients and low normal in the remaining 13. Serum DHEA-S levels were decreased in 11 of these 13 patients. The frequency of decreased serum DHEA-S levels in patients with secondary adrenal insufficiency was significantly higher than that of decreased cortisol levels. These results suggest that decreased serum DHEA-S levels reflect deficient ACTH secretion in secondary adrenal insufficiency and that simultaneous determination of serum DHEA-S and cortisol levels is useful in the diagnosis of this pathological state.

Adolescent↗
PubMed1987

Changes in membrane potentials and currents of ventricular cells of the guinea pig heart by a new cardiotonic drug, MCI-154.

Effects of MCI-154, a newly synthesized cardiotonic drug with vasodilator property, on the membrane potential and currents of the isolated papillary muscles and the single ventricular cells of the guinea pig were examined. MCI-154 (10(-7)-10(-4) M) increased the developed tension in a dose-dependent manner without significant changes in the action potential configuration of the guinea pig papillary muscle. The slow response action potential obtained by increasing the extracellular K+ concentration to 24 mM was augmented by MCI-154 (10(-6) and 10(-4) M). This effect of MCI-154 was not blocked by atenolol (10(-6) M). In voltage clamp experiments on single ventricular cells, the slow inward current was not affected, but the inward rectifier K+ current was reduced by higher concentration of MCI-154 (10(-4) M). Considering the "run down" phenomenon of the slow inward current, the possibility that MCI-154 might have a slight increasing effect on the slow inward current could not be ruled out. From these results, it can be concluded that the positive inotropic action of MCI-154 can be explained partially by the decrease in the inward rectifier K+ current, and probably by the increase in the Ca2+ sensitivity of the contractile protein system.

Action Potentials↗
PubMed1987

Mechanisms of action of a novel macromolecular antitumor antibiotic, SN-07, on mouse leukemia L1210 cells in culture.

The mechanisms of action of a novel macromolecular antitumor antibiotic (SN-07) were examined using cultured mouse lymphoid leukemia L1210 cells. A shoulder exponential-type cytotoxicity was observed when the cells were treated with 3.13 to 100 ng/ml SN-07 for 1 hr and surviving colonies were counted after a 14-day incubation. It was found that 500 ng/ml SN-07 inhibited both RNA and DNA syntheses significantly at 40 and 80 min, respectively, while 8,000 ng/ml did not affect protein synthesis at 80 min. Treatment with a low concentration (80 ng/ml) of SN-07 for 1 hr inhibited both RNA and DNA syntheses after a 24-hr post-incubation. The alkaline elution technique revealed that 8,000 ng/ml SN-07 induced DNA interstrand cross-links time-dependently for 1 to 4 hr, and a 1-hr treatment with 80 to 8,000 ng/ml SN-07 induced DNA breaks after a 24-hr post-incubation. According to flow cytometric analysis, most L1210 cells progressed to the G2 phase in the cell cycle at a cytostatic concentration (25 ng/ml) of SN-07, and typical inhibition of the cell cycle progression was observed at a cytocidal concentration (200 ng/ml).

Animals↗
PubMed1987

Effect of Sar1-Ileu8-angiotensin on renal prostaglandin E2 biosynthesis and excretion.

To test the hypothesis that renal prostaglandin (PG) biosynthesis is regulated by angiotensin (AII), rabbits were given prolonged treatment with the AII analogue, Sar1-Ileu8AII (200 micrograms/kg/4 hr, subcutaneously), for 2 days during a low, normal, and high sodium intake. Sodium restriction augmented plasma renin activity (PRA), which was associated with a rise in basal renal PGE2 synthesis and urinary excretion, whereas sodium supplementation attenuated PRA with a decrease in renal PGE2 synthesis and urinary excretion. Sar1-Ileu8AII administration, with either a low, normal, or high salt intake, suppressed PRA. Sar1-Ileu8AII injection with a low sodium intake also suppressed renal PGE2 synthesis and excretion that was associated with a fall in blood pressure, suggesting an antagonistic action of this agent on vascular beds and renal PGE2 synthesis. On the other hand, with a high sodium intake Sar1-Ileu8-AII increased renal PGE2 synthesis and excretion as well as blood pressure, revealing an agonistic action of this compound under these conditions. The results suggest that exogenous AII analogue may act as an antagonist or agonist depending on sodium intake and endogenous AII levels, renal PGE2 synthesis is dependent on AII levels, either endogenously produced or exogenously administered (as an AII agonist), and the action of AII analogue on vascular beds and renal PGE2 synthesis does not appear to parallel its action on renin-AII feedback regulation at the juxtaglomerular cell especially under conditions of high sodium intake.

1-Sarcosine-8-Isoleucine Angiotensin II↗