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Biomedical subjects

H Fukuda

Publications and source records attributed to H Fukuda.

At least 1,045 records · Page 58Linked to original sources
PubMed1984

Supraspinal tonic influence on spinal reflexes and involvement in the effect of chlorpromazine.

Chlorpromazine (CPZ) depressed mono-(MSR) and polysynaptic reflexes in anesthetized rats. The MSR remained unaltered after spinal transection (C1). After spinal transection, the inhibitory effect of CPZ on the MSR disappeared. After CPZ injection, spinal transection enhanced the MSR to pre-drug level. Reserpine pretreatment abolished the inhibitory effect of CPZ on the MSR. Phenoxybenzamine inhibited the MSR and, when pre-injected, markedly attenuated the effect of CPZ on the MSR. These results suggest that in anesthetized rats, CPZ blocks the alpha-adrenoceptor-mediated facilitatory component of the spontaneous tonic influence on the MSR.

Animals↗
PubMed1984

Isolation and characterization of N-long chain acyl aminoacylase from Pseudomonas diminuta.

N-Long chain acyl aminoacylase II (Enzyme II) catalyzing the hydrolysis of N-long chain acyl amino acids was purified about 2,000-fold from the cell extracts of Pseudomonas diminuta with 1.8% of activity yield. The purified enzyme was homogeneous on polyacrylamide gel electrophoresis and the molecular weight was 220,000. Enzyme II differed from N-long chain acyl aminoacylase I (Enzyme I) in molecular weight, in substrate specificity, and in behavior toward temperature and pH. Enzyme II showed broader substrate specificity than Enzyme I and catalyzed the hydrolysis of lipoamino acids containing various amino acid residues, although Enzyme I was almost specific to the lipoamino acids containing L-glutamate. The extent of hydrolysis by Enzyme II reaction varied depending on the kinds of lipoamino acids and were: 100% for palmitoyl-L-glutamate, 91% for myristoyl-L-glutamate, 85% for lauroyl-L-glutamate, 54% for lauroyl-L-aspartate, 28% for stearoyl-L-glutamate and 17.5% for lauroyl-glycine.

Amidohydrolases↗
PubMed1984

The intramural pelvic nerves in the colon of dogs.

The intramural pelvic nerves of the dog colon were studied morphologically and electrophysiologically. These nerves emanate from the pelvic plexus, and ascend between the muscle layers along 57.5% of the colon's length. Many thin branches connect with Auerbach's plexus. Most of the nerves responded bilaterally with compound action potentials of A delta and C fibres to stimulation of the sacral dorsal roots, and with those of C fibres to stimulation of the ventral roots. Mean conduction velocities of the A delta and C fibres were 9.0 and 0.9 m/s, respectively. Distension of a section of colon at up to 85.0% of the length of the colon from the anus activated afferent fibres, and electrical stimulation of points at up to 102% of this length elicited responses in efferent fibres. In dogs in which the continuity of the colonic wall was interrupted by a ligature but the nerves were left intact, the intramural pelvic nerves were found to convey centrifugal activities of the recto- and ano-colonic reflexes to the proximal colon, and centripetal and centrifugal activities of the colo-colonic reflex.

Action Potentials↗
PubMed1984

Mechanisms of depressant action of muscle relaxants on spinal reflexes: participation of membrane stabilizing action.

The participation of local anesthetic action in spinal reflex inhibition produced by mephenesin-type muscle relaxants was examined by comparing the local anesthetic effects (in vitro), the depressant effects on muscle afferent discharges (in situ) and the depressant effects on spinal reflexes (in situ) of the drugs in rats. At doses producing depression of spinal reflexes, mephenesin, tolperisone (mephenesin-type) and lidocaine (local anesthetic) reduced the frequency of afferent discharges from the muscle. The order of reducing afferent discharges by these drugs corresponded to that of their conduction blocking activities in the isolated sciatic nerve of rats. These results suggest the participation of a membrane stabilizing action in spinal reflex inhibition produced by mephenesin-type muscle relaxants. Baclofen (non-mephenesin-type) did not show any local anesthetic action.

Action Potentials↗
PubMed1984

Curved laryngotelescope.

The purpose of this paper is to report on a newly developed curved laryngotelescope whose shape allows for smooth insertion through the oral and to the laryngeal cavity. Its principle of image processing involves lenses and prisms, which results in the maximum magnification of x6. Therefore, it is very useful for microscopic examination. We can obtain a clearer picture by this device than by conventional laryngoscopes. Examination with this laryngotelescope is easily performed after only topical application of a local anesthetic and patients experience less pain.

Fiber Optic Technology↗
PubMed1984

Changes in the multiple components of rat pituitary TSH and TSH beta subunit following thyroidectomy.

Heterogeneity of pituitary TSH was investigated in rats following thyroidectomy. Adult male rats were sacrificed at varying periods (2-28 days) after thyroidectomy. In another experiment, thyroidectomized rats were injected daily with various doses of L-T4 (0.3-7.5 micrograms/100 g body weight, ip) and sacrificed 2 weeks later. The homogenate of the pituitaries was applied on an isoelectric focusing column or a Sephacryl S-200 column. The normal rat pituitary contained 5 major components of immunoreactive (IR) TSH in isoelectric focusing, in which the isoelectric point (pI) ranged from 6.6 to 8.8. The multiple components of IR-TSH beta were observed almost in the same areas as those of IR-TSH. Following thyroidectomy IR-TSH components with more acidic pI, associated with IR-TSH beta, were evident. A large amount of IR-TSH beta in the pituitaries of thyroidectomized rats appeared near the void volume in gel filtration, suggesting the presence of big TSH beta. Supplement of L-T4 minimized these thyroidectomy-induced changes in isoelectric focusing and gel filtration. Furthermore, big IR-TSH beta was little affected by ultracentrifugation and was relatively stable after treatment with 6 M guanidine hydrochloride. We demonstrated that the rat pituitary gland contained multiple components of IR-TSH and IR-TSH beta, both of which became variegated after thyroidectomy. It is suggested that a discernible degree of heterogeneity of TSH, particularly of TSH beta, is dependent upon the increased rate of TSH biosynthesis at the pituitary level.

Animals↗
PubMed1984

Physiological impairment in linoleic acid deficiency of rats and the effect of n-3 polyunsaturated fatty acids.

Some impairments related to membrane function were found in linoleic acid-deficient rats and the effects of fish oil feeding were investigated. In linoleic acid-deficient rats, glucose transport into erythrocytes was decreased. The concentrations of plasma free fatty acids were significantly reduced in the animals. Further, epinephrine-stimulated lipase was remarkably less sensitive to epinephrine in the deficient rat than in the corn oil-fed control rat. However, these impairments were relieved by fish oil feeding. Therefore, the impairments may be ascribed to the decrease of arachidonic acid as a polyunsaturated fatty acid in membrane phospholipids, since n-3 polyunsaturated fatty acids appear to take the place of arachidonic acid.

Adipose Tissue↗
PubMed1984

[Regional cerebral blood flow in limbic seizures induced by microinjection of kainic acid into amygdala in cats].

The relationship between neuronal epileptic activity and regional cerebral blood flow was studied by means of hydrogen clearance method (rCBF). Measurements of rCBF in the limbic structure and cerebral cortex were performed during limbic seizures induced by a microinjection of kainic acid to the left amygdala under concurrent monitoring of polygraph. Pentobarbital (35 mg/kg, i.p.) anesthesia was induced and cats were artificially ventilated. Physiological parameters such as blood pressure, body temperature, PaO2, PaCO2 and HCO3 were kept stable. After fixation of the cat's head in a stereotaxic device, stainless screw electrodes were placed over bilateral anterior sigmoid gyrus so as to touch the dura mater for cortical EEG monitoring. Bipolar needle electrodes were stereotaxically placed to both amygdala and the left dorsal hippocampus. Platinum electrodes were stereotaxically placed to the left amygdala, dorsal hippocampus and sensorimotor cortex. After measurements of control rCBF, a microsyringe was stereotaxically inserted into the left amygdala and kainic acid solution (2 micrograms) was injected. Polygraphic monitoring followed. Five to 30 minuted after kainic acid injection, continuous multiple spikes appeared in the left amygdala. Forty to 120 minutes later, continuous multiple spikes transmitted to the left hippocampus. Two to five hours later, limbic seizure occurred. The limbic seizure lasted five to eight hours and interictal discharges appeared. Repeated measurements of rCBF were done. In the left amygdala, rCBF increased about two-fold of the control immediately after development of continuous multiple spikes and remained increased as long as the seizure persisted.(ABSTRACT TRUNCATED AT 250 WORDS)

Amygdala↗