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Biomedical subjects

N Sakamoto

Publications and source records attributed to N Sakamoto.

At least 433 records · Page 24Linked to original sources
PubMed1983

Aminophenyl ether compound (YM-95831), a new hypolipidemic agent with a high density lipoprotein elevating activity in rats.

A single oral dose of a new hypolipidemic agent, 4-(cis-p-menthan-8)benzanilide (YM-95831) exhibited a marked elevation of high density lipoprotein (HDL) cholesterol with great reduction of serum total cholesterol in rats which were fed hypercholesterolemic diet. Reduction of serum total cholesterol preceded the increase in HDL, reached a peak at 16 h and was still significant even after 112 h. When YM-95831 was orally given daily for 4 days to the hypercholesterolemic rats, the dose required to reduce serum total cholesterol by 50% was about 6 mg/kg. Clofibrate was more than 10 times less potent than YM-95831 in the hypolipidemic activity. Nicotinic acid was virtually ineffective. HDL cholesterol was doubled by YM-95831 of about 3 mg/kg, but not significantly influenced by clofibrate of 200 mg/kg. Nicotinic acid at 400 mg/kg increased 1.5 times HDL cholesterol. Polyacrylamide gel electrophoresis of the serum demonstrated the decrease in beta-lipoprotein and the increase in alpha-lipoproteins by YM-95831. In hypercholesterolemic rats. YM-95831 increased preferentially HDL2 (d: 1.063-1.125) without significant alteration of a HDL3 (d: 1.125-1.21) level. YM-95831 tempted to decrease liver total cholesterol. Nicotinic acid significantly decreased the cholesterol whereas clofibrate exhibited no alteration. These results indicate that YM-95831 is a potent and long-lasting hypolipidemic agent with a potent HDL cholesterol elevating activity.

Anilides↗
PubMed1982

Fiber connections of the corpus glomerulosum in a teleost, Navodon modestus.

Fiber connections of the corpus glomerulosum (CG) in a teleost, Navodon modestus, were studied by means of horseradish peroxidase (HRP) and the Fink-Heimer methods. The CG is divided into a pars anterior (GA) and a pars rotunda (GR). Both the GR and the GA have the same cell components and glomeruli. The GR is composed of four layers arranged concentrically around a central fiber net in the following order (Ito and Kishida, '75): a glomerular layer, a fibrous layer, a small-cell layer, and a peripheral fibrous capsule including large cells. The GA consists of a central glomerular layer and a peripheral small-cell layer which contains some large cells. Following HRP injections into the GR, HRP-positive cells were found bilaterally in the nucleus corticalis and ipsilaterally in the nucleus intermedius of Bricker ('29). Lesions of the nucleus corticalis produced degenerating terminals bilaterally in glomeruli in the CG. The course of the fiber connections was coincident with that of the commissura horizontalis. Lesions of the nucleus intermedius resulted in degenerating terminals in the fibrous layer of the GR and the small-cell layer of the GA. Following the destruction of the GR, degenerating terminals occurred in the ipsilateral lobus inferior. Both small and large cells in the ipsilateral CG were labeled after HRP injections into the lobus inferior.

Animals↗
PubMed1982

Cytoarchitecture, fiber connections, and ultrastructure of nucleus isthmi in a teleost (Navodon modestus) with a special reference to degenerating isthmic afferents from optic tectum and nucleus pretectalis.

Cytoarchitecture and fiber connections of the nucleus isthmi in a teleost (Navodon modestus) were studied by means of Nissl, Bodian, toluidine blue, Golgi, and Fink-Heimer methods. Synaptic terminals were classified by the ultrastructural characteristics, and their origins were determined by electron microscopic degeneration experiments. The nucleus isthmi is composed of an outer cellular area or shell and an inner noncellular area or core. The shell covers anterior, dorsal, and ventral aspects of the core. The cell bodies in the shell are oval (15 x 20 micrometers) with an anteroposterior long axis, and have many somatic spines. Spines are also seen on the initial segment of the axon. Primary dendrites extend posteromedially and branch out in the core. The core contains thin and thick myelinated fibers, which originate in the optic tectum and in the nucleus pretectalis, respectively. At least two types of axon terminal were distinguished in the nucleus isthmi: S type, containing spherical vesicles, and F type, containing flattened vesicles. S terminals are derived from thin myelinated fibers and are only seen in the core where they form asymmetric synapses with dendrites. Frequently a portion of the S terminal membrane near the usual synaptic cleft is in close apposition with the membrane of an adjacent small dendrite or spine. F terminals, which derived from thick myelinated fibers, make symmetric synaptic contacts with both cell bodies in the shell and dendrites in the core. S terminals degenerate after ipsilateral ablation of the optic tectum, whereas F terminals degenerate after destruction of the nucleus pretectalis.

Animals↗
PubMed1982

Decreased synaptic areas on Purkinje spines in the cerebellar cortex of the mutant Japanese quail, Coturnix coturnix japonica.

'Dark frayed feather nervous disorder' (dn) is a neurological mutation in quails in which the cerebellar cortex is abnormally organized. Purkinje cells are not aligned in a single row and show hypoplasia of the dendrites. The synapses between the parallel fibers and the spines of the Purkinje cell dendrites were examined with the technique of serial sections in electron microscopy. The postsynaptic thickenings were obviously decreased in the mutant quail despite the same density and size of dendritic spines of Purkinje cells. In addition, ectopic spines and postsynaptic differentiations free of parallel fibers were not found on the dn Purkinje cell. Because of the poor dendritic arborization, the total number of spines and the total synaptic area are, therefore, reduced in the dn Purkinje cell. According to the results obtained the dn mutant genetic locus is considered to affect primarily Purkinje cells.

Animals↗
PubMed1982

Cross-sectional echocardiographic study on atrial septal defect: pre- and postoperative considerations.

The interatrial septum (IAS) has not been readily appreciated by M-mode echocardiography, but cross-sectional echocardiography has the capability of recording the shape and location of the IAS. Thirty-five patients with secundum atrial septal defect (ASD) were studied with cross-sectional echocardiography for detection of the ASD defect and demonstration of the IAS features following ASD closure. The ASD was shown as an echo dropout at the mid-portion of the septum in those patients examined in the present study in the horizontal cross-sections at the fourth intercostal space. The edge of the remaining IAS sharply demarcated and the defect was constantly demonstrated. In the postoperative patients, the IAS was recognized as a smooth series of echoes and the defect was no longer recognized. A notch echo was demonstrated in patients who underwent direct suture of the defect, and two notch echoes were recorded in patients who had a patch closure from a cardiac operation. The size of the defect at cardiac operation ranged from 1.5 to 5.0 cm with an average of 3.3 +/- 0.2 cm. The defect was slightly smaller on cross-sectional echocardiograms than at the time of operation. As the defect grew larger, the right ventricular dimension and the Qp/Qs became larger as well. Postoperatively, the right ventricular dimension was remarkably decreased, and the paradoxical movement of the interventricular septum (IVS) was normalized in the majority of the patients. Cross-sectional echocardiography is useful to diagnose ASD, to measure the size of the IAS defect, and to follow the clinical course.

Adolescent↗
PubMed1982

[Diabetic coma].

Explore the source record for details and available documents.

Diabetic Coma↗
PubMed1981

Topographic projections between the nucleus isthmi and the optic tectum in a teleost. Navodon modestus.

Following horseradish peroxidase injections into the optic tectum of a teleost, Navodon modestus, reciprocal and topographic projections between the nucleus isthmi and the ipsilateral optic tectum were determined. The isthmo-tectal fibers diverge to the optic tectum while maintaining the spatial arrangements of the isthmic cells from which the fibers originate. The tecto-isthmic projections also keep the spatial arrangements in the optic tectum. The tectal fibers converge near the nucleus isthmi and terminate in the non-cellular portion of the nucleus. The reciprocal topography is apparent in the combined results of 9 experiments with one tectal injection in each region. No labeled cells and fibers were found in the contralateral nucleus isthmi.

Animals↗
PubMed1981

A retinopetal nucleus in the preoptic area in a teleost, Navodon modestus.

Following horseradish peroxidase (HRP) applications to the optic nerve of a teleost (Navodon modestus), a retinopetal nucleus was identified in the contralateral preoptic area. The nucleus was composed of small (7-10 microns) round cells. Centrifugal fibers from the nucleus were traced to the inner nuclear layer of the ipsilateral retina by both orthograde HRP and Fink-Heimer methods. The cells in the nucleus showed no neurosecretion. The retinopetal nucleus or neurons could not be found in Carassius carassius. No retinopetal neurons were found in the optic tectum in both species.

Afferent Pathways↗