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Biomedical subjects

T Muraki

Publications and source records attributed to T Muraki.

At least 109 records · Page 6Linked to original sources
PubMed1984

The staining properties of thiazolylazoalkylaminophenol derivatives in histochemical staining of cadmium.

In the continuous research for a more sensitive chelator for cadmium, thiazolylazoalkylaminophenol derivatives were synthesized. The staining sensitivity for cadmium and molar absorptivity of their cadmium chelates were examined. Though the molar absorptivity of bromothiazolylazodiethylaminophenol(Br-TADA)-cadmium chelate demonstrated an order of 10(5), the staining sensitivity of Br-TADA was unexpectedly low. The lowering of the sensitivity of Br-TADA may be attributed to alkaline hydrolysis and a decrease in the stability constant of the cadmium chelate.

Azo Compounds↗
PubMed1984

[Quality control of radioimmunoassay by bivariate analysis].

Automatic calculation of control charts for precision and accuracy of radioimmunoassay was reported by Faure, et al. Duplicate control samples independently measured was assumed to have a bivariate normal distribution. In this case they assumed that the correlation coefficient between each value of the pairs of control samples is zero. Our experience using this method revealed that a considerable number of assayed samples distributed outside the calculated control limits in case of "accuracy control". It was considered that this happened because in radioimmunoassay the between-assays precision is usually larger than the within-an-assay precision and there is a significant correlation between values of duplicates. We also found equal probability density did not make a true circle but a long circle. Therefore in the present paper we proposed for control charts of radioimmunoassay an equal probability long circle calculated by bivariate analysis of Mahalanobis' generalized distance. It was found that a Mahalanobis' long circle could explain the density distribution of radioimmunoassay with a reasonable percent of samples outside the calculated control limits. What happened here can be interpreted by a large between-assays variability shown by some commercial kits. This automatic calculation method could be applied not only for quality control but also for evaluation and comparison of radioimmunoassay system or commercial kits. Control survey could also be analyzed by such a method.

Analysis of Variance↗
PubMed1983

Developmental changes in the effect of morphine, epinephrine and carbachol on plasma cyclic nucleotide level in rats.

The developmental changes in the effects of morphine, FK 33-824, a synthetic opioid peptide, epinephrine and carbachol on the plasma cyclic AMP and GMP level were investigated in rats ranging in age from 1 to 49 days. The effect of morphine in elevating plasma cyclic AMP and GMP level increased with age with a peak at day 21. The effect of FK 33-824 followed a similar developmental course of that of morphine except at day 49. Epinephrine and carbachol increased the plasma cyclic AMP level even in one-day old rats. The increase in plasma cyclic GMP induced by carbachol increased with age, peaked at day 14, then declined until day 49. These results suggest that the delay in advent of the effect of opioids on plasma cyclic nucleotides in the early neonatal period is mainly due to the slow development of opioid receptors in the brain.

Aging↗
PubMed1983

The staining properties of pyridylazophenol analogs in histochemical staining of a metal.

The compound 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Br-PADAP) was found capable of staining very small amounts of metals in tissue. This finding stemmed from the examination of the staining properties of pyridylazophenol analogs; 2-(2-pyridylazo)-phenol, 2-(2-pyridylazo)-5-dimethylaminophenol, 1-(2-pyridylazo)-2-naphthol, 4-(2-pyridylazo)-resorcinol, and Br-PADAP. The unusually high sensitivity of Br-PADAP is attributed to the presence of an alkylamino group at the 5-position of the benzene ring. The presence of this alkylamino group forms a charged quinoid structure, and contributes resonance and optimum solubility to the hybrid by introducing a bromine atom into the pyridine ring. We report the staining results obtained from a variety of metals and the molar absorptivity of their metal chelates.

Animals↗
PubMed1983

The choice of a masking agent in the histochemical staining of metals.

The masking effects of standard masking agents (aminopolycarboxylic acids, carboxylic acids and phosphates) have been investigated in both test-tube experiments and tissue sections in order to ascertain the factors which must be considered when choosing a masking agent for the histochemical staining of a metal. The masking effects in vitro were determined by spectrophotometry through the complexing of the dye Chrome Azurol S with aluminium, beryllium, and iron at pH 5 and 7. The effects were also examined by staining metal-containing tissue sections in a Chrome Azurol S masking agent system at the same pH values. In many cases, the masking effects observed in sections did not agree with those obtained in the test-tube experiments. This means that the published values of stability constants are not a sufficient guide for choosing a suitable masking agent for the staining of metals. The discrepancy is mainly attributable to the presence of protein in a solid state when metals are stained in sections. Therefore, in the future, consideration should be given to a metal-protein or masking agent-protein interaction using a model compound such as a chelate resin. The polyphosphates are among the most useful masking agents for metal staining in acidic solutions from a practical standpoint.

Animals↗
PubMed1983

Mechanism of morphine in increasing plasma cyclic GMP level in male mice.

Morphine given systemically or centrally increases the plasma concentration of cyclic GMP in male, ddY strain mice. Normorphine also increased the plasma cyclic GMP level, whereas the same dose of ketocyclazocine and SKF 10,047 had no effect. The effect of morphine on plasma cyclic GMP was mimicked by opioid peptides such as (D-Ala2, Met)-enkephalinamide, FK 33,824 or beta-endorphin. The effect of morphine and opioid peptides on plasma cyclic GMP was antagonized by naloxone, indicating the involvement of the opiate receptor. The increase in plasma cyclic GMP elicited by morphine was abolished by vagotomy and pretreatment with hexamethonium and atropine and was partly inhibited by pretreatment with phentolamine. Adrenalectomy and pretreatment with propranolol, which inhibited the increase in plasma cyclic AMP level elicited by morphine (Muraki et al., 1979), did not alter the cyclic GMP response to morphine. The development of tolerance to the cyclic GMP increase was observed in morphine-tolerant/dependent mice. These results suggest that morphine increases the plasma cyclic GMP level by activating the preganglionic parasympathetic tone via the stimulation of the opiate receptors, thereby increasing the generation of cyclic GMP through the muscarinic receptors on the effector cells.

Adrenalectomy↗
PubMed1983

[Factors affecting the serum thyroid hormone concentration during fasting in rats--with special reference to the relation with temperature].

The present studies examine the effect of starvation together with cold or hot exposure on thyroid hormone levels in rats. At 23 degrees C starved for 5 days, serum thyroid hormone levels decreased significantly compared with fed rats, averaging 3.6 +/- 0.5 micrograms/dl of thyroxine (T4), 47 +/- 11 ng/dl of triiodothyronine (T3), 1.4 +/- 0.3 ng/dl of free T4 and 39.6 +/- 5.1 pg/ml of reverse T3, respectively. At 15 degrees C rats starved for 5 days, serum free T4 level significantly more increased than that of 23 degrees C starved rats, while serum T4 level and T3 did not increase significantly. At 30 degrees C rats whether concomitant starvation or not, serum thyroid hormone levels of both group markedly more decreased than control rats. These experiment provide additional evidence that thyroid gland and the peripheral metabolism of thyroid hormone respond to variety situations such as cold or hot exposure together with starvation or not.

Animals↗
PubMed1982

Involvement of alpha 1-adrenergic receptors in stimulation of phosphatidylinositol metabolism by catecholamines in mouse thyroids.

The effects of alpha-adrenergic agonists and thyroid stimulating hormone on the incorporation of radioactive phosphate into phosphatidylinositol were investigated in mouse thyroids in vitro. The incorporation of 32P orthophosphate into phosphatidylinositol was stimulated by thyroid stimulating hormone, norepinephrine (a mixed alpha 1- and alpha 2-adrenergic agonist), methoxamine and phenylephrine (alpha 1-agonists) and slightly by clonidine and oxymetazoline (alpha 2-agonists) but not by isoproterenol (beta-agonist). Prazosin (alpha 1-antagonist) inhibited the stimulation by norepinephrine of 32P incorporation into phosphatidylinositol, but yohimbine (alpha 2-antagonist) was less effective. Although norepinephrine inhibits the thyroid stimulating hormone-induced release by activating alpha-, especially alpha 1-adrenoceptors in mouse thyroids [M. L. Maayan et al., Metabolism 26, 473 (1977); M. L. Maayan et al., Endocrinology 101, 284 (1977); T. Muraki et al., Endocrinology 110, 51 (1982)] alpha 1-agonists did not decrease the stimulation of turnover elicited by thyroid stimulating hormone and did not have additive action with it. These results suggest that (1) the stimulation of phosphatidylinositol turnover of mouse thyroids elicited by adrenergic agonists is mediated by activation of alpha 1-adrenoceptors and (2) the inhibitory effect of norepinephrine on the thyroid stimulating hormone-induced release of thyroxine is not mediated by norepinephrine-inhibition of phosphatidylinositol-turnover stimulated by thyroid stimulating hormone.

Adrenergic alpha-Agonists↗
PubMed1982

Strain difference in morphine-induced increase in plasma cyclic AMP and cyclic GMP levels in relation to locomotor activity in male mice.

The effects of morphine on plasma cyclic nucleotide levels and on locomotor activity were investigated in four inbred strains of male mice. Morphine increased both cyclic AMP and cyclic GMP levels as well as locomotor activity in C57BL/6N mice. In BALB/cAnN mice, morphine increased plasma cyclic GMP levels and motor activity without changes in plasma cyclic AMP levels. In C3H/HeN mice, morphine increased plasma cyclic GMP levels without changing cyclic AMP levels and motor activity, but neither plasma cyclic nucleotide levels nor motor activity were increased by morphine in DBA/2N mice. Epinephrine and carbachol increased plasma cyclic AMP and cyclic GMP levels, respectively, in both C57BL and DBA mice. These results show that there is a significant strain difference in the effects of morphine on plasma cyclic nucleotide levels as well as motor activity. The major cause of strain difference in the effects of morphine on cyclic nucleotide levels is unlikely to be due to the difference in the regulation of adenylate cyclase linked to adrenoceptors or that of guanylate cyclase connected with cholinoceptors.

Animals↗
PubMed1982

Histochemical staining of cadmium with benzothiazolylazonaphthol derivatives.

Searching for a chelator with increased sensitivity for use as cadmium stain, a number of benzothiazolylazonaphthol derivatives were synthesized and their staining properties for cadmium and zinc were examined. Benzothiazolylazo-beta-naphthol and -naphthol AS (BTAN-AS) stained cadmium with the highest staining intensity and the most precise localization. Poststaining techniques for differential staining using oxine solution made it possible to distinguish cadmium in the presence of interference by other metals. The observed lowered molar absorptivity of BTAN-AS is believed to be due to the ortho effect of the anilide group of naphthol AS. The solubility of the chelator appears to be a critical factor in the formulation of molecules with higher chelator sensitivities for metal staining.

Animals↗