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Biomedical subjects

Y Shinoda

Publications and source records attributed to Y Shinoda.

At least 91 records · Page 5Linked to original sources
PubMed1987

[General pharmacological studies on isepamicin sulfate (HAPA-B)].

General pharmacological properties of isepamicin sulfate (HAPA-B), a new aminoglycoside antibiotic, were studied in animals and the results obtained were summarized below. Intramuscular injections of HAPA-B at doses of 500 mg/kg inhibited the writing response induced by acetic acid, and at doses of 1,000 mg/kg, caused muscle relaxation, respiratory depression, suppression of spontaneous motor activity and prolongation of thiopental anesthesia. Anticonvulsive action and the effect on the rectal temperature were not observed. Intravenous Intravenous HAPA-B showed no significant effect on the general behavior and the function of the central nervous system at doses of 100 mg/kg. Intravenous injections of HAPA-B to anesthetized dogs resulted increases in the femoral arterial blood flow at doses of 12.5 mg/kg, decrease in the blood pressure and increase in the respiratory rate at doses of 25 mg/kg, and increase in the carotid arterial blood flow at doses of 50 mg/kg. Apparent changes were not recognized in the heart rate and electrocardiograms. In conscious rabbits, intravenous HAPA-B produced increases in the heart rate without significant changes of the blood pressure and electrocardiograms at doses of 100 mg/kg. Spontaneous beatings of isolated atria were depressed by HAPA-B in concentrations of 3 X 10(-4) to 10(-3) g/ml. The HAPA-B inhibited the gastric secretion at intramuscular doses of 500 mg/kg or intravenous doses of 100 mg/kg, and depressed charcoal transport through small intestine and the spontaneous movement of isolated ileum at intramuscular doses of 1,000 mg/kg and at concentrations of 3 X 10(-4) to 10(-3) g/ml, respectively. No irritative effect was found on the gastric mucous membrane. Intravenous HAPA-B inhibited the response of nictitating membrane to pre and post ganglionic stimulations of cervical sympathetic nerve at doses of 100 mg/kg. In in vitro test, HAPA-B inhibited nonspecifically the constrictive responses of trachea, aorta, stomach, ileum and vas deferens to various agonists in concentrations of 3 X 10(-4) to 10(-3) g/ml. Spontaneous movements of uteri of estrous or pregnant animals were depressed by HAPA-B at intravenous doses of 50 to 100 mg/kg and in in vitro at concentrations of 10(-4) to 3 X 10(-4) g/ml. Antidiuretic effect was also observed at intramuscular doses of 250 mg/kg. HAPA-B increased the length of the whole blood clotting time and raised the plasma glucose level at intramuscular doses of 1,000 mg/kg and inhibited the platelet aggregation induced by ADP in vitro at concentrations of 10(-3) g/ml.(ABSTRACT TRUNCATED AT 400 WORDS)

Aminoglycosides↗
PubMed1986

The morphology of single lateral vestibulospinal tract axons in the lower cervical spinal cord of the cat.

The intraspinal morphology of single lateral vestibulospinal tract (LVST) axons was investigated with the method of intra-axonal staining with horseradish peroxidase (HRP) and three-dimensional reconstruction of the axonal trajectory. Axons penetrated in the ventral funiculus at C5-C8 were identified as LVST axons by their monosynaptic responses to stimulation of the ipsilateral vestibular nerve and by their direct responses to stimulation of the ipsilateral Deiters' nucleus and LVST. Reconstructions were made from 34 well-stained LVST axons. Of these, 23 terminated in the brachial segments (C5-Th1) and the other 11 projected below Th2. These axons were traced over distances of 2.9-16.3 mm rostrocaudally. Within these lengths, one to seven axon collaterals (mean +/- S.D., 3.2 +/- 2.0, N = 19) were given off at right angles from the stem axons of LVST axons terminating in the brachial segments. The mean diameters of stem axons and primary collaterals were 4.5 microns and 1.6 micron, respectively. In the gray matter, collaterals ramified successively, pursued a delta-like path, and terminated mainly in laminae VII and VIII or lamina IX. The rostrocaudal extension of a single collateral was very restricted (mean +/- S.D., 760 +/- 220 microns, N = 16), in contrast to the extensive dorsoventral and mediolateral extent of the terminal arborization. There were usually gaps between adjacent collateral arborizations from the same stem axons, since the intercollateral distances ranged from 400 to 4,300 microns (mean = 1,490 microns). LVST axons terminating in brachial segments were divided into two groups--a medial group and a lateral group--on the basis of their projection sites in the transverse plane of the gray matter. The axons of the medial type had their main projection to laminae VII and VIII of Rexed, while those of the lateral type terminated in lamina IX. The terminal arborizations of the medial type LVST axons were mainly distributed over lamina VIII, where synaptic boutons appeared to make contact with proximal dendrites or somata of medium-sized and large neurons in the ventromedial nucleus and also in the medial portion of lamina VII adjacent to the central canal and dorsal to lamina VIII. Five out of 15 medial type axons had a bilateral projection. One or two collaterals of each of these axons crossed the midline through the anterior commissure and terminated in lamina VII or VIII. It was concluded that the contralateral projection was sparse.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1986

Synaptic organization of the cerebello-thalamo-cerebral pathway in the cat. III. Cerebellar input to corticofugal neurons destined for different subcortical nuclei in areas 4 and 6.

To analyze the cerebellar effects on corticofugal neurons destined for different subcortical nuclei, intracellular recordings were made from corticofugal neurons in areas 4 and 6 of the cat. Corticonuclear neurons to the red nucleus (RN) and the pontine nucleus (PN), and pyramidal tract neurons (PTNs) with collaterals to these nuclei were identified by their antidromic responses to the stimulation of these nuclei and the pyramid. Three types of RN-projecting neurons (corticorubral neurons (CRNs), corticopontine neurons (CPNs) with a collateral to the RN and PTNs with a collateral to the RN) and two types of PN-projecting neurons (CPNs and PTNs with a collateral to the PN) were differentiated. Furthermore, these corticofugal neurons were classified as fast and slow neurons on the basis of a critical axonal conduction velocity of 20 m/s. About 80% of 98 RN-projecting neurons in area 4 were PTNs, and among the rest, CPNs were more common than CRNs. A similar tendency of the frequency distribution of 37 RN-projecting neurons was also observed in area 6. In area 4, about 70% of 158 PN-projecting neurons were PTNs (80 fast and 30 slow PTNs) and the rest were CPNs, while in area 6, only 35% of 99 PN-projecting neurons were PTNs (10 fast and 25 slow PTNs). Among the CPNs in areas 4 and 6, slow CPNs were more frequently encountered. Cerebellar effects on these identified corticofugal neurons were investigated, using electrical stimulation of the brachium conjunctivum (BC). In both areas 4 and 6, a substantial number of fast conducting CRNs, CPNs and PTNs projecting to the RN or the PN received short-latency (predominantly disynaptic), large-amplitude EPSPs from the BC, and a considerable number of slow conducting neurons to the RN and/or the PN received longer-latency, smaller-amplitude EPSPs from the BC.

Animals↗
PubMed1986

Multiple axon collaterals of single corticospinal axons in the cat spinal cord.

To investigate intraspinal branching patterns of single corticospinal neurons (CSNs), we recorded extracellular spike activities from cell bodies of 408 CSNs in the motor cortex in anesthetized cats and mapped the distribution of effective stimulating sites for antidromic activation of their terminal branches in the spinal gray matter. To search for all spinal axon branches belonging to single CSNs in the "forelimb area" of the motor cortex, we microstimulated the gray matter from the dorsal to the ventral border at 100-micron intervals at an intensity of 150-250 microA and systematically mapped effective stimulating penetrations at 1-mm intervals rostrocaudally from C3 to the most caudal level of their axons. From the depth-threshold curves, the comparison of the antidromic latencies of spikes evoked from the gray matter and the lateral funiculus, and the calculated conduction times of the collaterals, we could ascertain that axon collaterals were stimulated in the gray matter rather than stem axons in the corticospinal tract due to current spread. Virtually all CSNs examined in the forelimb area of the motor cortex had three to seven branches at widely separated segments of the cervical and the higher thoracic cord. In addition to terminating at the brachial segments, they had one to three collaterals to the upper cervical cord (C3-C4), where the propriospinal neurons projecting to forelimb motoneurons are located. About three quarters of these CSNs had two to four collaterals in C6-T1. This finding held true for both fast and slow CSNs. About one third of the CSNs in the forelimb area of the motor cortex projected to the thoracic cord below T3. These CSNs also sent axon collaterals to the cervical spinal cord. CSNs in the "hindlimb area" of the motor cortex had three to five axon branches in the lumbosacral cord. These branches were mainly observed at L4 and the lower lumbosacral cord. None of these CSNs had axon collaterals in the cervical cord. CSNs terminating at different segments of the cervical and the thoracic cord were distributed in a wide area of the motor cortex and were intermingled. To determine the detailed trajectory of single axon branches, microstimulation was made at a matrix of points of 100 or 200 micron at the maximum intensity of 30 microA, and their axonal trajectory was reconstructed on the basis of the location of low-threshold foci and the latency of antidromic spikes.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Labelling of cerebellar mossy fiber afferents with intra-axonal horseradish peroxidase.

Several unidentified units recorded in the intermediate zone of lobules IV and V of the cerebellar cortex responded to superficial radial nerve stimulation with a distinctive short train of 5 to 11 low amplitude spikes (less than 5 mV) at a frequency of 800 to 1200 Hz. Responses of this type have in the past been attributed to mossy fiber afferents. Following the electrophysiological characterization horseradish peroxidase was successfully injected by iontophoresis into four axon terminals. The labelled axons presented the typical structure of mossy fibers with terminal rosettes and corresponded to the morphology of these axons described in Golgi material.

Afferent Pathways↗
PubMed1985

Synaptic organization of the cerebello-thalamo-cerebral pathway in the cat. I. Projection of individual cerebellar nuclei to single pyramidal tract neurons in areas 4 and 6.

The neural connections of the dentate (DN) and the interpositus (IN) nuclei to the motor cortex and area 6 were investigated by recording intracellular postsynaptic potentials from fast and slow pyramidal tract neurons (PTNs) in the anesthetized cat. Localized stimulation of DN and IN produced di- or polysynaptic EPSPs in fast and slow PTNs in the "forelimb area" of the motor cortex and area 6. The effects of stimulation of the two cerebellar projections were essentially the same, although some regional difference of their relative strength was noted. In these cortical areas, the majority of fast and slow PTNs received convergent inputs from both DN and IN. By examining the interaction of DN- and IN-evoked EPSPs, spatial facilitation and occlusion at the level of the thalamus were demonstrated. Therefore, it was concluded that at least a portion of the convergence of the dentate and the interpositus inputs occurred at the level of the ventrolateral nucleus of the thalamus.

Animals↗
PubMed1985

Synaptic organization of the cerebello-thalamo-cerebral pathway in the cat. II. Input-output organization of single thalamocortical neurons in the ventrolateral thalamus.

Input-output neural organization of single thalamocortical (T-C) neurons in the ventrolateral nucleus (VL) of the thalamus was investigated using an intracellular recording technique in the anesthetized cat. Stimulation of the dentate (DN) and the interpositus (IN) nuclei produced monosynaptic unitary EPSPs of large amplitude in T-C neurons projecting to the motor cortex or area 6 over the entire mediolateral region of VL. The thalamic projections from DN and IN are very wide and there is a considerable overlap between the dentate and the interpositus projection areas in VL. And in this overlapping area, a considerable number of T-C neurons (50%) receive inputs from both DN and IN. More than 40% of T-C neurons were antidromically activated from widely separated electrodes in the motor cortex, indicating that the cortical arbolization of single T-C neurons is very wide and the number of these neurons with widely divergent projections is considerably large.

Animals↗
PubMed1983

Malignant tumor of the eyelid--clinical survey during 22-year period.

A total of 52 malignant tumors of the eyelid treated at Kyushu University Hospital during the 22-year period from 1960 through 1981 were analyzed. The peak incidence in this series was in patients 70-79 years of age. There were 26 each of men and women. Squamous cell carcinoma was the lesion most frequently seen, i.e. in 25 cases (48.1%). Basal cell carcinomas were detected in 17, sebaceous adenocarcinomas in 7 malignant melanomas in 2 and malignant lymphoma in 1. In 13 cases, there were squamous cell carcinomas in the upper eyelid, 10 with basal cell carcinomas in the lower eyelid, and all with sebaceous adenocarcinomas in the upper eyelid. Follow-up information was obtained on 42 of the 52 cases. Twenty-four out of these 42 patients were living and 18 had died. There were two recurrences of squamous cell carcinomas and two of basal cell carcinomas. In two, there was a metastasis to the lung and in one the regional lymph nodes were involved. Thus, squamous cell carcinoma was the most frequently encountered malignant tumor of the eyelid seen in this series. We wish to stress the importance of examining specimens histologically, to ensure a rapid diagnosis and pertinent treatment.

Adenocarcinoma↗
PubMed1983

Empty sella syndrome with visual field disturbance.

Three patients with empty sella syndrome with various visual field disturbances were reported. In one patient there was evidence of enlargement of Mariotte spots, and in the others, irregular visual field defects. These three patients were initially suspected to have intraocular tumors because of the balloonings of the sella and visual field disturbances. However, the diagnosis of empty sella was confirmed by metrizamide cisternography and metrizamide computed tomography(CT). The results indicate that the patient with enlargement of the sella on the plain skull X-ray and visual field disturbance should be examined by metrizamide cisternography and metrizamide CT scan to differentiate from the intrasellar tumor.

Aged↗
PubMed1982

Convergent inputs from the dentate and the interpositus nuclei to pyramidal tract neurons in the motor cortex.

Effects of stimulation of the cerebellar nuclei were investigated by intracellular recordings from fast and slow pyramidal tract neurons and thalamocortical neurons in the cat. The present study demonstrated that: (1) the interpositus and the dentate nuclei excite PTNs in the motor cortex; (2) single pyramidal tract neurons receive convergent inputs from both nuclei, and (3) the convergence of the inputs from both nuclei occurs at the level of the ventrolateral nucleus of the thalamus.

Animals↗
PubMed1981

Divergent projection of individual corticospinal axons to motoneurons of multiple muscles in the monkey.

Intracellular staining with horseradish peroxidase (HRP) of physiologically identified corticospinal (CS) axons originating from the monkey motor cortex revealed the intraspinal morphology of their branching patterns. CS collaterals spread in a delta-like fashion in the intermediate zone and lamina IX. Virtually all CS axons examined terminated in lamina IX, and it was shown by labeling motoneurons with retrograde transport of HRP that individual CS axons made direct contacts with dendrites of motoneurons of different muscle species.

Animals↗