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Biomedical subjects

H Fukuda

Publications and source records attributed to H Fukuda.

At least 1,135 records · Page 63Linked to original sources
PubMed1981

Age-dependent modifications of lipogenic enzymes.

When 1-, 2- and 9-month-old rats previously adapted to a commercial stock diet were fed a fat-free diet (induction) and also when the process was reversed (repression), the turnovers of lipogenic enzymes in liver were measured by following time courses for the change of the enzyme activities. The magnitudes of the induction of glucose-6-phosphate dehydrogenase, malic enzyme and acetyl-CoA carboxylase were very high in 1-month-old rats and then decreased with aging. In the induction phase, the rates of synthesis of the enzymes were markedly decreased with increasing age as compared with the rate constants of degradation. The age-dependent alterations were not shown so much in the repression phase as in the induction phase. It is suggested that the age-dependent impairment in induction may be due to some alterations in the enzyme-forming system.

Acetyl-CoA Carboxylase↗
PubMed1981

Changes of electroretinogram and neurochemical aspects of GABAergic neurons of retina after intraocular injection of kainic acid in rats.

The effect of kainic acid (KA) on both electroretinogram (ERG) readings and neurochemical properties of the retina was investigated in rats with emphasis placed upon examination of the events that occur immediately following KA treatment. KA was injected into the eyes of rats with doses of 50 and 200 nmol. One hour after injection, histological alterations became evident. Swelling was observed in the inner and outer plexiform layers. Certain ganglion cells and cells of the inner nuclear layers exhibited pyknotic nuclei. Most of the ganglion cells appeared to have degenerated 48 h following injection, and the form of the outer plexiform layer was incomplete. The amplitude of the b-waves of the ERG decreased 2 h following injection and never recovered. The amplitude of the a-waves was unaffected by KA. The gamma-aminobutyric acid content in the eyecups began to decrease within 1 h and fell to approximately 20% of its original level 24 h following injection. The taurine content in the eyecups was unaffected by KA. The activity of glutamic acid decarboxylase remained unaffected for 2 h after injection, but was reduced to approximately 40% of its original activity by 24 h after injection. A possible explanation for the mechanism by which KA effects degenerative changes in the rat retina is that KA induces release of neurotransmitters through stimulation of neurons, and degeneration in the soma follows.

Animals↗
PubMed1981

Pontine reticular unit responses to pelvic nerve and colonic mechanical stimulation in the dog.

The role of pontine reticula units (PRU) responding to afferent impulses from the distal colon and anal mucosa was studied in dogs. The 465 PRU were classified into 4 groups on the basis of the pattern of discharge in response to afferent stimulation (AS) of rectal branches (RB) of the pelvic nerve: Group I (G-I) responded with a short burst (latency, 36 +/- 16 msec); G-II responded with an early short burst (latency, 41 +/- 21 msec), followed by a late long-lasting train of spikes (latency, 187 +/- 110 msec); and G-III responded with a long-lasting train of spikes (latency, 189 +/- 130 msec). G-IV had spontaneous discharges which were temporally inhibited by AS. G-II and G-III PRU showed remarkable facilitation similar to that of the long latency reflex discharges of RB. G-I PRU showed habituation. Most of G-II and G-III PRU discharged simultaneously with the reflex discharges of RB; these cause the contractions of defecation in the distal colon. In each group, 6.4 +/- 14.8% of PRU were reticulospinal units with descending axons running beyond the 1st lumbar segment of the spinal cord. It was concluded that the pontine defecation reflex center plays an essential role in defecating activity.

Afferent Pathways↗
PubMed1981

The binding of cholic acid to protein in rat serum and liver.

After the intraperitoneal administration of radioactive cholic acid to rats, the binding of the cholic acid to protein was immunologically investigated. The serum and liver cytosol were separately incubated with antiligandin or antialbumin immunoglobulin and then subjected to sucrose density gradient centrifugation. The sedimentation behavior of the radioactivity, endogenous bile acids, glutathione S-transferase activity of ligandin and protein provided evidence that cholic acid is bound to both ligandin and albumin in liver, and mostly to albumin in serum. However, little, if any, cholic acid seems to be bound to protein in bile. These results suggest that ligandin and albumin are the major physiological carriers of bile acid.

Animals↗
PubMed1981

Persistence of the circadian rhythm of REM sleep: a variety of experimental manipulations of the sleep-wake cycle.

Many studies of nocturnal sleep, daytime naps, and phase shifts of sleep time indicate that rapid eye movement (REM) sleep has a circadian rhythm with an acrophase in the early morning, whereas slow wave sleep (SWS) correlates positively with the length of prior wakefulness. We confirmed that REM sleep has a stable circadian variation; large REM sleep amounts occurred in morning naps despite increase of SWS, owing to 1 night of total sleep deprivation. Heart rate and oral temperature both continued to show a circadian rhythm in spite of 1 night of total sleep deprivation. The lowest point of both cycles occurred in the early morning and the highest point in the late afternoon. The amount of REM sleep was largest near the low point of the circadian cycle of oral temperature and heart rate, and smallest at the high point, indicating a phase reversal relationship between the circadian rhythm of REM sleep and the autonomic functions. During 1 week of absolute bed rest under entrained conditions, subjects were most able to sleep near the low point of their oral temperature cycle and least able to sleep near the high point, and the amount of REM sleep was largest near the low point of the oral temperature and smallest at the high point.

Adult↗
PubMed1981

Arteriovenous malformation of the brain -- histological study and micrometric measurement of abnormal vessels.

An autopsy case of arteriovenous malformation (AVM) of the brain in a 29-year-old housewife was reported. Several important and characteristic findings were obtained by detailed histological examination and micrometric measurement of abnormal vessels composing the nidus of the AVM. Structural imperfectness and immaturity of their vascular wall suggested that the AVM is a histoembryogenic maldevelopment. Prominent dilatation in calibre, hypertrophy of muscular layer, hyalinization, and abnormal increasing of elastic fibers were interpreted as the result of changed cerebral hemodynamics caused by an arteriovenous fistulous communication.

Adult↗
PubMed1981

Kininogen and kallikrein in saliva of periodontally-diseased subjects.

The kininogen level in saliva was measured by radioimmunoassay, and the kallikrein activity was determined by an enzymatic method with D-Val-Leu-Arg-p-nitroanilide. The kininogen level in the Periodontally-diseased Group was remarkably high compared with that of the Periodontally-healthy Group, but the kallikrein activity was approximately the same in the two groups.

Adult↗
PubMed1981

Excitation by lyoniol-A of vagal afferent nerves and the reflex autonomic and somatic actions in rats.

Lyoniol-A (2mg/kg, i.v.), a toxic component isolated from the Ericaceous tree, markedly caused the increase in rate of discharges from vagal afferent nerves in the rat. This agent also caused respiratory depression, hypotension and the relief of decerebrate rigidity. These effects of lyoniol-A on the respiration an the rigidity were absent under conditions of bilateral cervical vagotomy, and the hypotension was abolished by sectioning of both vagal and carotid sinus nerves. These results suggest that the excitation by lyoniol-A of the afferent activities reflexly produces respiratory depression, hypotension and the relief of decerebrate rigidity.

Animals↗
PubMed1981

Decrease in effects of muscimol on the dorsal root after repeated administration of diazepam in rats.

In in situ experiments on spinal rats transected at the C1 level and on non-spinal rats, muscimol (3 mg/kg, i.v.) depolarized the primary afferent fibers and diazepam (3 mg/kg, i.v.) potentiated this effect of muscimol. When diazepam was given for 14 days, the effect of muscimol was significantly reduced in non-spinal rats. These findings suggest that diazepam probably interacts with GABA-ergic mechanisms more closely in supraspinal regions of the rat.

Animals↗