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Biomedical subjects

T Noguchi

Publications and source records attributed to T Noguchi.

At least 865 records · Page 48Linked to original sources
PubMed1986

Receptor dynamics and tyrosine aminotransferase induction during the course of chronic treatment of rats with glucocorticoid.

The changes in the cytosol glucocorticoid receptor (GR) content during a long-term administration of a glucocorticoid were studied to examine the mechanism of the development of steroid hormone resistance. Dexamethasone (Dex) (0.2 microgram/ml and 2.0 micrograms/ml) was given to adrenalectomized rats, and the GR content was determined using the exchange assay 1, 10, 20 and 50 days after the start of administration. The activity of tyrosine aminotransferase (TAT) in the cytosol was also assayed as a measure of the biological responsiveness of these animals to the administered glucocorticoid. The dissociation constant (Kd) was elevated and the Bmaxs of the GR in the cytosol were decreased by the lower concentration of Dex. The Bmaxs decreased to 30% of the untreated controls within 24 h and this lower level was maintained as long as the hormone treatment continued. On the other hand, the cytosol obtained from animals treated with 2.0 micrograms/ml of Dex for 20-24 days did not show any measurable amount of binding to 3H-Dex. The activity of TAT was elevated 24 h after the administration of Dex but decreased gradually and steadily with time during the experimental period. To examine the biological potency of remaining GR in the liver cytosol, 2.0 micrograms/ml Dex was again administered after a long-term treatment. This treatment eliminated the remaining GR completely and induced TAT at almost the same rate as observed in the untreated control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenalectomy↗
PubMed1986

An immunocytochemical and electron microscopic study of the hyt mouse anterior pituitary gland.

The hyt mutant mouse used in this study has a hypoplastic thyroid gland and is characterized by retarded somatic growth, very low to undetectable levels of plasma thyroxine (T4), and increased levels of plasma thyroid-stimulating hormone (TSH). This congenital hypothyroid mouse is therefore an ideal model for studying the effects of thyroid hypofunction on the adenohypophysis. The anterior pituitary of the hyt mouse appeared less granular than that of the normal control when viewed by light microscopy, owing to a decrease in the population of somatotrophs. Many cells, in various stages of transformation into 'thyroidectomy cells', were recognized by the appearance of the characteristic granules and dilated rough endoplasmic reticulum. In some cases, the enlarged rough endoplasmic reticulum also contained spherical electron-dense secretory granules. In addition there were many cells undergoing mitosis and these were identified as thyrotrophs by their characteristic granules. Administration of T4 during the first 40 days of life prevented the abnormal changes in the hyt anterior pituitary. A reduction in immunoreactive thyrotrophin-releasing hormone (TRH) levels was seen in the median eminence of the hyt mouse. Treatment with T4 restored this to normal, suggesting that the reduced TRH content of the hypothalamus of the mutant mouse may be due to T4 deprivation.

Animals↗
PubMed1986

Functional morphology of the conduction system and the myocardium in the sheep heart as revealed by scanning and transmission electron microscopic analyses.

The pacemaker, Purkinje system and myocardium of the sheep heart were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In the case of SEM, the heart tissues were subjected to chemical digestion procedures. The nodal cells in both the sinoatrial (SA) node and atrioventricular (AV) node were small in size and contained few nexuses with poor sarcoplasmic reticulum and myofibrillar development. These nodal cells were spindle-shaped and their ends often showed ramifications. In addition, the strands of nodal cells in the central part of the AV node were considerably compact and connected with neighboring strands to form a complicated three dimensional architecture. The muscle cells in the common bundle and Purkinje system were cuboidal or oval in shape and were broader and shorter than the working cardiac muscle cells. They had abundant nexuses, but exhibited poor sarcoplasmic reticulum and myofibrillar development. Three-dimensionally, the Purkinje strands formed a delicate network resembling a fishing-net. The atrial and ventricular myocardium consisted of long cylindrical muscle cells which often bifurcated and connected with neighboring cells. These cells had abundant nexuses, rich sarcoplasmic reticulum and well-developed myofibrils. This report discusses such morphological findings in correlation with their physiological properties.

Animals↗
PubMed1986

Endoscopic ultrasonography of lymph nodes surrounding the upper GI tract.

We investigated the usefulness of endoscopic ultrasonography (EUS) of lymph nodes surrounding the upper GI tract and tried the enhanced EUS by the method of the oral administration of '10% oil-in-water-type emulsion.' The results were as follows: The ultrasonographic visualization rate of lymph nodes surrounding the esophagus was 33.7% in total; however, it was 43.4% for those greater than 5 mm and 58.7% for those greater than 10 mm. The frequency of lymph node metastasis of esophageal cancer was 48.1% for those larger than 10mm with a round shape and 14.3% for the same size with an ellipsoid shape; for those less than 10mm, it was also low. Lymph nodes surrounding the esophagus and the stomach were enhanced by administration of 10% oil-in-water-type emulsion. The visualization rate of lymph nodes can be increased by using this new method. Endoscopic ultrasonography is very useful for the detection of swelling lymph nodes surrounding the upper GI tract before the operation.

Endoscopy↗
PubMed1986

Casein phosphopeptide (CPP) enhances calcium absorption from the ligated segment of rat small intestine.

A casein phosphopeptide (CPP) was prepared from beta-casein of cow's milk and the effect of this peptide on the absorption of calcium from a ligated segment of rat small intestine was investigated. CPP injected into a ligated loop of rat small intestine enhanced absorption of calcium from the loop and augmented the deposition of calcium in the femur. Furthermore, CPP inhibited the precipitation of calcium phosphate in vitro, suggesting that this peptide enhances calcium absorption from the small intestinal lumen by increasing the concentration of soluble calcium. This new evidence confirms our previous hypothesis that CPP is an important factor in raising the availability of calcium in milk.

Animals↗
PubMed1986

Calcium-dependent and -independent tumoricidal activities of polymorphonuclear leukocytes induced by a linear beta-1,3-D-glucan and phorbol myristate acetate in mice.

Some antitumor immunomodulators, such as a linear beta-1,3-D-glucan from Alcaligenes faecalis var. myxogenes IFO 13140 (TAK), induce potent tumoricidal activity of polymorphonuclear leukocytes (PMNs). In the present study we investigated the role of calcium on the tumoricidal activity of PMNs induced by immunomodulators, especially TAK. The calcium chelator ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) almost completely inhibited TAK-induced PMN cytotoxicity and this inhibition was restored by Ca2+ but not by Mg2+. In Ca2+- and Mg2+-free medium, PMN cytotoxicity induced by TAK was recovered by the addition of Ca2+ provided that Mg2+ was also present. By scopoletin assay, hydrogen peroxide released from PMNs by TAK was also observed in the presence of Ca2+ but not in its absence. The PMN cytotoxicities induced by the other immunomodulators, Propionibacterium acnes, Bacillus Calmette-Guérin, zymosan A, and Nocardia cell wall skeletons were also Ca2+ dependent, judging from studies with EGTA and measurement of hydrogen peroxide release in the presence and absence of Ca2+. The Ca2+ dependency of these PMN cytotoxicities suggests that Ca2+ influx is involved in the cytolytic process, but PMN cytotoxicity was not induced by simple addition of the calcium ionophore A23187. Like TAK, phorbol myristate acetate induced PMN cytotoxicity but this cytotoxicity was not Ca2+ dependent. The present report demonstrates the difference in Ca2+ dependency of these PMN cytotoxicities; i.e., extracellular calcium was required for immunomodulator-induced PMN cytotoxicity, but not for phorbol myristate acetate-induced PMN cytotoxicity. This suggests that the processes of induction of PMN cytotoxicity by the two types of activators are not identical.

Adjuvants, Immunologic↗
PubMed1986

A new method of closed reduction using the spring action of Kirschner wires for fractures of the tibial plateau--a preliminary report.

The treatment of fractures of the lateral tibial plateau is still a subject of controversy. Many authors have emphasized the importance of early mobilization of the knee joint following fractures of the tibial plateau. However, local depression fractures of the tibial plateau occur quite frequently in elderly patients and have presented many difficult problems in management. In 1982, the authors developed a new method of closed reduction using the spring action of Kirschner wires for severely displaced local depression fractures of the tibial plateau. The principle of this procedure is to apply continuous positive pressure to the depressed fragment for its reduction and retention. By re-establishing stability in the fracture, active knee mobilization can be allowed from the beginning. Seven patients were treated with this procedure, and the results of short-term follow-up, ranging from three to 26 months, were promising as to the range of motion, stability and relief of pain.

Adolescent↗
PubMed1986

[A case of downhill esophageal varices--Behçet disease associated with abdominal aortic aneurysm and occlusions of the superior and inferior vena cava].

A case of Behçet disease which vascular lesions progressed remarkably and had massive gastrointestinal bleeding is reported. A 39 year old man was admitted to the hospital complaining of intractable abdominal pain and angiography revealed impending rupture of a saccular aneurysm just above the bifurcation of the aorta. Aneurysmectomy and patch closure of the defect were performed. Four months later, the patient was admitted again complaining of severe abdominal pain and rerupture of the patch graft was recognized by RI angiography. Aorto-iliac bypass was carried out. Although postoperative course was excellent, the sign of superior vena cava syndrome appeared gradually. Venography revealed occlusion or stenosis of the bilateral subclavian and brachiocephalic veins and the superior vena cava. Femoral venography revealed occlusion of the inferior vena cava, too. Two years and three months later of the first operation, the patient had hematemesis and the extensive varicose vein of the entire esophagus was seen by the upper gastrointestinal examination. Five months later of the examination the patient suddenly had massive gastrointestinal hemorrhage and died in spite of vigorous resuscitative therapy. This esophageal varices was considered as downhill esophageal varices caused by superior vena caval occlusion, not by portal hypertension. Downhill esophageal varices due to mediastinal tumor is seen sporadically, but one due to superior vena caval occlusion secondary to Behçet disease is very rare.

Adult↗