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N Murakami

Publications and source records attributed to N Murakami.

At least 541 records · Page 30Linked to original sources
PubMed1985

Thyroid carcinoma in benign thyroid diseases. An analysis from minute carcinoma.

The relative frequency of thyroid carcinoma in benign thyroid diseases such as toxic diffuse goiter (toxic goiter), adenomatous goiter (goiter), adenoma, and chronic thyroiditis (thyroiditis) was studied using 3,219 surgically removed thyroid glands. Coexistence of carcinoma and benign diseases was found in 257 glands. Among them, 157 glands had minute carcinoma (diameter of cancer nodule is smaller than 10 mm) and 100 glands had advanced carcinoma (larger than 10.1 mm in diameter). The incidence of carcinoma including minute carcinoma was 29.4% in goiter (98/333), 21.0% in thyroiditis (11/53), 8.6% in adenoma (55/638), and 5.3% in toxic goiter (98/1852). Chi-square test also revealed that the rate of carcinoma not only advanced carcinoma but also minute carcinoma was higher in goiter than in the other diseases (P less than 0.01, respectively). Among the patients aged under 39, the incidence of advanced carcinoma and minute carcinoma in thyroiditis were the highest, respectively (83% and 100% in thyroiditis, 9.0% and 11.4% in goiter, 2. 6% and 1.9% in adenoma, and 0.7% and 3.4% in toxic goiter), however, among the patients aged over 40, they were secondary lower and the lowest, respectively (19% and 16.8% in goiter, 5.2% and 7.5% in adenoma, 4.2% and 6.7% in thyroiditis, and 1.4% and 7.5% in toxic goiter). We concluded that adenomatous goiter accompanies carcinoma more frequently than other benign thyroid diseases and the high incidence of carcinoma in chronic thyroiditis is probably due to a preoperative selection of the patients.

Adenoma↗
PubMed1985

[14C]deoxyglucose incorporation into rat brain regions during hypothalamic or peripheral thermal stimulation.

The central nervous structures involved in thermoregulatory responses induced by hypothalamic or peripheral thermal stimulation were investigated in conscious rats by means of the 2-deoxy-D-[14C]glucose ([14C]-DG) autoradiographic technique. According to autoradiographs, many brain regions with significant increases or decreases in [14C]-DG incorporation were observed during thermoregulatory responses. Based on the present changes in [14C]-DG incorporation of brain regions obtained from two kinds of thermal stimulation, the following conclusions were drawn. 1) The medial preoptic area and the medial forebrain bundle are common sites for development of thermoregulatory responses being activated during cooling and warming. 2) The anterior hypothalamic area is activated during hypothalamic or peripheral warming and not during cooling. 3) The ventromedial hypothalamus, dorsomedial thalamus, caudate-putamen, globus pallidus, pars compacta of the substantia nigra, red nucleus, and the midbrain reticular formation are activated with hypothalamic or peripheral cooling. 4) The lateral preoptic area, suprachiasmatic nucleus, ventroposteromedial thalamus, pars reticulata of the substantia nigra, and the hippocampus change their activities only during peripheral cooling and warming.

Animals↗
PubMed1984

Requirement of the 20-kDa light chain for the papain-resistant conformation of gizzard myosin.

The limited chymotryptic digestion of unphosphorylated gizzard myosin in 0.15 M NaCl converted a papain-insensitive myosin in ATP to a papain-sensitive one. This conversion without phosphorylation of its 20-kDa light chain was accompanied with truncation of a 200-kDa heavy chain to a 195-kDa fragment and with the degradation of a 20-kDa light chain. Papain also yielded the 195-kDa fragment from the heavy chain, irrespective of the presence or absence of ATP. However, the ATP-induced protection of unphosphorylated myosin from the papain-digestion disappeared concurrently with degradation of the 20-kDa light chain by papain rather than the truncation of heavy chain. Papers from two laboratories [Onishi, H. & Watanabe, S. (1984) J. Biochem. (Tokyo) 95, 903-905; Kumon, A., Yasuda, S., Murakami, N., and Matsumura, S. (1984) Eur. J. Biochem. 140, 265-271] have reported that the ATP-protection of unphosphorylated myosin against papain is not observed after the 20-kDa light chain has been phosphorylated. The present results might indicate that the ATP-induced protection is also abolished through the chymotryptic degradation of the 20-kDa light chain.

Adenosine Triphosphate↗
PubMed1984

Effect of light on the acetylcholine concentrations of the suprachiasmatic nucleus in the rat.

Acetylcholine concentrations were determined in suprachiasmatic nucleus of rats sacrificed by irradiation of microwave, using radioimmunoassay. No significant rhythmicity was observed over a 24-h period in rats blinded for two weeks. When the light was given at 22.00 h (illumination schedule L:07.00-19.00 h) in intact rats, acetylcholine concentration increased 30 and 60 min after light on in suprachiasmatic nucleus, but not in the other control site. These results suggest that endogenous circadian rhythm of acetylcholine concentration is absent in suprachiasmatic nucleus, but light may affect acetylcholine concentration of this site.

Acetylcholine↗
PubMed1984

Discrimination of assembled and disassembled forms of gizzard myosin by papain.

Chicken gizzard myosin in 0.15 M or 0.5 M NaCl was cleaved at two sites of heavy chain with 2-10 micrograms/ml papain. MgATP inhibited these cleavages of myosin in 0.15 M NaCl but not in 0.5 M NaCl. The protective effect of ATP was observed at concentrations as low as 10 microM and increased in proportion to ATP concentration to a maximum at 1 mM. ADP was as effective as ATP, while adenosine 5'-[beta, gamma-imido]triphosphate, an unhydrolyzable ATP analogue, was less effective than ATP or ADP. AMP had no protective effect on the digestion of myosin and GTP inhibited slightly the digestion. When the papain-insensitive myosin in 0.15 M NaCl and 2.5 mM MgATP was phosphorylated by Ca2+/calmodulin-dependent myosin light-chain kinase, the myosin restored the vulnerability to papain. However, the two papain-susceptible forms, nonphosphorylated form in the absence of MgATP and phosphorylated form in the presence of MgATP, yielded very similar but distinct proteolytic fragments upon the digestion. When the extent of myosin assembly was estimated by the turbidimetry of myosin suspension in 0.15 M NaCl, nonphosphorylated myosin in the absence and presence of MgATP was assembled and disassembled, respectively, and phosphorylated myosin in the presence of MgATP was assembled. These results suggest that, at physiological ionic strength, papain as a probe distinguishes disassembled myosin and assembled myosin as papain-insensitive and papain-sensitive forms, respectively.

Adenosine Triphosphate↗
PubMed1984

The phosphorylation site for casein kinase II on 20,000-Da light chain of gizzard myosin.

The 20-kDa light chain isolated from gizzard myosin has recently been reported to be phosphorylated by casein kinase II at a site distinct from that phosphorylated by Ca2+- and calmodulin-dependent myosin light-chain kinase. In the present study, the site phosphorylated by casein kinase II has been analyzed through procedures including tryptic digestion of the radioactively phosphorylated light chain and CNBr cleavage of the purified tryptic phosphopeptide, followed by amino acid analysis of these phosphopeptides. Comparison of the amino acid compositions of these peptides with the previously reported sequence has indicated that the phosphorylation site is threonine-134 of the light chain. The significance of the phosphorylation of the light chain by casein kinase II, as well as the substrate specificity of the protein kinase, is discussed on the basis of the result.

Amino Acids↗
PubMed1984

Critical period for the entrainment of the circadian rhythm in blinded pups by dams.

The critical period for the entrainment of circadian rhythm in blinded pups by a foster mother with a rhythm inverted to that of the natural mother was determined by a convenient method for the analysis of the circadian rhythm of drinking behavior. The pups, optically enucleated on day 1, were transferred to the foster mother at various ages, measured in days from birth, and raised until weaning. When the pups were transferred before 4 days of age, the drinking rhythm of the adopted pups was in phase with that of the blinded natural pups born of and raised by the foster mother. On the other hand, when the mother was exchanged after 10 days of age, the rhythm of the adopted pups was out of phase with that of the natural pups of the foster mother. Pups exchanged on 5 or 7 days of age showed inconsistent phase of rhythm, either being entrained by the foster or the natural mothers, or affected by both mothers. These results indicate that blinded pups must be adopted by the foster mothers earlier than day 4 for the foster mothers to fully entrain the circadian rhythm of blinded pups.

Animals↗
PubMed1984

Activation of brain regions in rats during food-intake operant behavior.

The central nervous structures involved in bar pressing and feeding behavior during food-intake operant behavior were investigated in rats by the [14C]-deoxyglucose ( [14C]-DG) autoradiographic technique. During bar pressing behavior, the [14C]-DG incorporation increased in the sensory-motor cortex, ventromedial thalamus, zona incerta, pars reticulata of substantia nigra, ligular cortex of the cerebellum and the reticular formation of the medulla. On the other hand, an increase of the [14C]-DG incorporation induced by feeding behavior was observed in the fornix, medial forebrain bundle, parietal cortex, trigeminal nuclei and the solitary nuclei.

Animals↗
PubMed1984

Influence of lesions in the limbic-hypothalamic system on metabolic response of acetate to daily repeated heat exposure in rabbit.

The effects of lesions in the basal medial hypothalamus and limbic structure on the acetate metabolic responses to daily repeated heat exposure in the liver of rabbits have been investigated. The results obtained were summarized as follows: (1) THe acetate metabolic responses to the 1st heat exposure (heat exposure on the 1st day) were altered by the lesions in the periventricular arcuate nucleus (ARC), ventromedial hypothalamus (VMH), stria terminalis (ST) and dorsal fornix (FX). (2) The acetate metabolic responses to heat exposure were completely abolished by the ten times repetition of heat exposure in the rabbits with lesions in ARC or VMH. They were similar to sham-operated animals. (3) The acetate metabolic responses to heat exposure remained even after the ten times repetition of heat exposure in the rabbits with lesions in ST and FX indicating the differences from sham-operated animals. (4) From these results, it might be suggested that the basal medial hypothalamus and limbic structure participated in the mechanism of acetate metabolic response to the 1st heat exposure, but only these limbic structure played some roles in the complete disappearance process of acetate metabolic responses to heat exposure by the ten times repetition of heat exposure.

Acetates↗
PubMed1984

Purification and identification of myosin heavy chain kinase from bovine brain.

A high salt extract of bovine brain was found to contain a protein kinase which catalyzed the phosphorylation of heavy chain of brain myosin. The protein kinase, designated as myosin heavy chain kinase, has been purified by column chromatography on phosphocellulose, Sephacryl S-300, and hydroxylapatite. During the purification, the myosin heavy chain kinase was found to co-purify with casein kinase II. Furthermore, upon polyacrylamide gel electrophoresis of the purified enzyme under non-denaturing conditions, both the heavy chain kinase and casein kinase activities were found to comigrate. The purified enzyme phosphorylated casein, phosvitin, troponin T, and isolated 20,000-dalton light chain of gizzard myosin, but not histone or protamine. The kinase did not require Ca2+-calmodulin, or cyclic AMP for activity. Heparin, which is known to be a specific inhibitor of casein kinase II, inhibited the heavy chain kinase activity. These results indicate that the myosin heavy chain kinase is identical to casein kinase II. The myosin heavy chain kinase catalyzed the phosphorylation of the heavy chains in intact brain myosin. The heavy chains in intact gizzard myosin were also phosphorylated, but to a much lesser extent. The heavy chains of skeletal muscle and cardiac muscle myosins were not phosphorylated to an appreciable extent. Although the light chains isolated from brain and gizzard myosins were efficiently phosphorylated by the same enzyme, the rates of phosphorylation of these light chains in the intact myosins were very small. From these results it is suggested that casein kinase II plays a role as a myosin heavy chain kinase for brain myosin rather than as a myosin light chain kinase.

Animals↗
PubMed1984

Endocytosis of human thyroglobulin (TG) in adenomatous goiter studied by an immuno-electron microscopic procedure.

Five cases of adenomatous goiter have been studied by an electron microscope using an immuno-reaction for thyroglobulin (TG) and focusing on the mechanism of endocytosis. Positive stain for TG was demonstrated in follicular lumina, large reabsorbed colloid droplets and small subapical vesicles. Endocytotic vesicles ranging from 320 nm to 1600 nm in diameter were observed in the cytoplasm as pits in the apical plasma membrane. Some of them showed direct connection with the positive stain for TG in the follicular lumen and the others were completely ingested in the cytoplasm. With statistic analysis, a majority of the vesicles showing the positive stain for TG in the cytoplasm distributed in the range of 200 nm to 1200 nm in diameter with the peak in 300 nm to 399 nm and was situated within an extent of the diameter measured from the endocytotic vesicles. Engulfment of colloid by pseudopods and fusion of the reabsorbed colloid droplets were encountered as extremely rare findings and appeared to play no major role for formation of large colloid droplets in adenomatous goiter.

Coated Pits, Cell-Membrane↗
PubMed1984

Ultrastructural localization of endogenous peroxidase in the human thyroid gland under normal and hyperfunctioning conditions.

Ultrastructural localization of human thyroid peroxidase in normal and hyperfunctioning states has been studied. Peroxidase activity was visualized ultrastructurally with a cytochemical reaction using 0.05% diaminobenzidine-tetrahydrochloride, and hydrogen peroxide with a final concentration of 0.0025%, 0.005%, or 0.01%, respectively, and 2% osmium tetroxide. Reaction product demonstrating the enzyme was clearly observed in cell organelles with a final concentration of hydrogen peroxide at 0.0025% or 0.005%. In the normal portion of thyroid, follicular cells demonstrated the reaction product, located mainly in rough-surfaced endoplasmic reticulum and perinuclear cisternae and in addition a small amount of the product was found in Golgi cisternae and small vesicles dispersed throughout the subapical cytoplasm. The reaction product significantly increased in amount in the cell organelles described above and in addition, a characteristic heavy deposition of the product was observed at the external surface of the microvilli in the follicular cells of thyroid obtained from the patients with treated Basedow's disease.

Endoplasmic Reticulum↗
PubMed1984

Further evidence that circadian rhythm of blinded rat pups is entrained by the nursing dam.

To determine the importance of the nursing mother in setting the phase of the endogenous rhythm in blinded rat pups, free-running rhythm of locomotor activity in the pups was observed during 4-5 wk after weaning. Blinded pups, optically enucleated on day 1, were raised by either an intact natural mother or an intact foster mother with a rhythm reversed to that of the natural mother. The locomotor activity was continuously recorded for 4-5 wk, starting between 3 and 5 postnatal wk. At 5 wk of age the offset time of activity phase was found during the periods corresponding to the middle half of the light phase in the nursing period, regardless of whether they were raised by a natural or a foster mother. The free-running periods, in the blinded pups tested, were fairly close, with the majority ranging between 24.3 and 24.5 h. These findings indicate that the endogenous rhythm of the blinded pups is entrained by the nursing mother during the nursing period.

Animal Population Groups↗
PubMed1984

Cavernous hemangioma with bone formation in a child: case report.

A 13-year-old girl suffering from seizures who was found to have hemangioma calcificans in the frontal lobe was surgically treated. The favorable postoperative course of our patient as well as reported cases suggest early excision of the lesion if it is located in an accessible area. Histological examination confirmed ossification with marrow in the lesion. The literature regarding ossification in the brain is discussed briefly.

Adolescent↗