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Biomedical subjects

K Hara

Publications and source records attributed to K Hara.

At least 1,153 records · Page 64Linked to original sources
PubMed1982

[General pharmacology of lisuride hydrogen maleate--actions on isolated organs, especially on smooth muscles].

Pharmacological actions of lisuride hydrogen maleate (lisuride) were studied by using isolated organs. 1) Lisuride at 2.2 microM exerted a negative chronotropic effect on guinea-pig atria, the effect being antagonized completely by 2.9 microM sulpiride. 2) alpha-Adrenolytic action of lisuride was observed in the rat vas deferens and beta-adrenolytic action in the rabbit trachea, respectively. The former (ID50 = 64 nM) was potent and equivalent to that of phentolamine, whereas the latter (ID50 = 26 microM) was only 1/30 as compared to that of propranolol. 3) Anti-5-hydroxytryptamine action (ID50 = 11 nM) was detected in the rat stomach and anti-histamine (ID50 = 15 nM) in the guinea-pig ileum, respectively. In these respective activities, lisuride was equipotent to methysergide and diphenhydramine. 4) Lisuride showed a spasmodic action, which may be categolized as an ergot alkaloid action, on the guinea-pig ileum and on rabbit renal artery. A weak positive inotropic action of lisuride was also observed in guinea-pig atria. In the rat uterus, however, no uterotonic action of lisuride was detected. It is concluded that, in addition to its known effects on the central nervous system, lisuride possesses potent peripheral anti-5-hydroxytryptamine and anti-histamine activities.

Animals↗
PubMed1982

[Central dopaminergic function in stroke-prone spontaneously hypertensive rats (SHRSP): I. Alteration of locomotor activity and swimming ability].

The possible alteration of central dopaminergic (DA) function, which accompanies the development and persistence of hypertension, was studied in SHRSP by measuring the lisuride-induced locomotor activity and the swimming ability. 1) When administered at a dosage of 50 micrograms/kg, lisuride, a DA agonist, induced significant increases of the locomotor activity in one- and 2-month-old Wistar Kyoto rats (WKY), but not in the 6 month-old rat. Differing from the response of WKY, SHRSP showed only a moderate increase in the locomotor activity at the age of one month (means of systolic blood pressure: 128 mmHg) and apparently no increase at the age of 2 months (176 mmHg). In 6 month-old SHRSP (238 mmHg), hypomotility but not hypermotility was induced by the lisuride administration. 2) Though no significant difference was detected at the age of 4 months, the swimming ability of SHRSP at the age of 8 months was deteriorated significantly as compared to that of WKY, and the impaired swimming performance of SHRSP was improved by the administration of lisuride. These results indicate that some alterations in the synaptic sites of the central DA neuron occurred already at an early stage of the hypertensive development, followed under persistent hypertension by the progressive deterioration of the motor-coordination ability as detected in the swimming ability.

Age Factors↗
PubMed1982

[Central dopaminergic function in stroke-prone spontaneously hypertensive rats (SHRSP): II. Effects of chronic treatment with lisuride on the impaired swimming ability].

Eight month-old SHRSP were treated s.c. with lisuride (50 micrograms/kg per day) for 5 weeks to examine the effect of the central dopaminergic agonist on the deterioration of swimming ability that occurred and progressed under persistent hypertension. General observations on signs and symptoms and histopathological examinations were also carried out with the same rats to evaluate the drug effect on the deterioration of hypertensive symptoms. The poor swimming performance of hypertensive SHRSP was improved significantly by the direct action of lisuride with a maximal effect at the 2nd week of the treatment, although the progress of the deterioration itself was not prevented by the chronic treatment. One week after the drug treatment, 2 out of 8 rats in the control group but none in the lisuride-treated group exhibited the abnormal behavior with aggressiveness, a typical sign of the occurrence of cerebrovascular lesions. Furthermore, macroscopic and histopathological examinations carried out 2 weeks after the drug treatment revealed that severities of the histopathological lesions such as myocardiac necrosis and arteriolosclerosis in the kidney, adrenal and testis were significantly lower in the lisuride-treated group than in the control.

Adrenal Glands↗
PubMed1982

[Effects of an ergot derivative, lisuride, on the central dopaminergic system -- studies of behavioral pharmacology].

The central dopaminergic (DA) activity of lisuride hydrogen maleate (lisuride) was investigated from the view point of behavioral pharmacology in rats and mice. Lisuride exhibited a biphasic action on locomotor activity in mice and rats; with low doses lisuride caused hypomotility, whereas higher doses produced locomotor stimulation. The hypomotility induced by lisuride (0.00625 mg/kg, s.c.) was antagonized by a low dose of sulpiride (10 mg/kg, i.p.) in rats, and the lisuride (0.05 mg/kg)-induced hyperactivity was inhibited with haloperidol (0.1 mg/kg, i.p.). The stimulatory effect of lisuride on locomotion was not affected by the combined pretreatment with reserpine and alpha-methyl-p-tyrosine. The hyperactivity of mice induced by methamphetamine was inhibited by pretreatment with lisuride. In the rat lesioned unilaterally in the nigro striatal pathway by a local injection of 6-hydroxydopamine, a low dose of lisuride induced rotational behavior contralateral to the side of the lesion, and the rotational behavior was inhibited by pretreatment with haloperidol. These results indicate that lisuride at low doses effectively stimulates pre-synaptic DA receptors and the post-synaptic DA receptor under supersensitization in the mesolymbic and nigro striatal systems.

Animals↗
PubMed1981

A reinvestigation of the role of the grey crescent in axis formation in xenopus laevis.

Gravitationally induced displacements of the contents of the frog egg can predictably determine the orientation of the subsequent dorsal-ventral axis of the embryo, regardless of the original position of sperm entry or of the grey crescent. In certain conditions, these displacements in the egg can also lead to the formation of a second axis, that is, to twinning. The previously reported ability of grafts of grey crescent cortex to induce secondary axes in recipient eggs is interpreted here as an unrecognized twinning effect of gravity. Our results lead to question the classic interpretation of the grey crescent as a dorsal determinant in amphibian development.

Animals↗
PubMed1981

Fine structure of trabecular meshwork and iris in pigmentary glaucoma.

Trabecular meshwork and iris were studied by light and electron microscopy in a 40-year-old female with pigmentary glaucoma. Elevation of the intraocular pressure was most likely due to closure the intertrabecular space by pigment granules and large cells resembling clump cells, fibrous substances, and hypertrophied endothelial cells of the trabecular sheet, which had phagocytized pigment granules.

Adult↗
PubMed1981

The value of EEG and cerebral evoked potentials in the assessment of neonatal intracranial hemorrhage.

The EEG, visual and auditory evoked potentials (VEP, AEP) were evaluated in 16 full-term newborn infants who had intracranial hemorrhage documented by computerized tomography (CT). Three of them had supratentorial, three, supra- and infratentorial hemorrhage, while the other ten had infra- or pri-tentorial bleeding. Three died during the neonatal period. Eight of the 13 surviving infants were neurologically normal and five were abnormal at the time of the follow-up. Those who had normal or mildly abnormal background EEGs all developed normally, while those whose neonatal EEG was severely abnormal subsequently developed neurological sequelae irrespective of the extent of intracranial hemorrhage. The EEG, VEP or AEP is of little value in the diagnosis of intracranial bleeding but the EEG is valuable in assessing the degree of associated parenchymatous damage and is of great prognostic significance.

Cerebral Hemorrhage↗
PubMed1981

Apparent brain atrophy and subdural hematoma following ACTH therapy.

A case of subdural hematoma following ACTH-Z therapy for infantile spasms was presented. A female baby of 5 months old showed little clinical evidence of cerebral dysfunction associated with subdural hematoma. There have been several reports about the relationship between steroid treatment and apparent brain atrophy on the CT brain scans. Then, we studied the CT brain scans before and after ACTH-Z therapy for infantile spasms, atonic seizure or Lennox syndrome and showed some relationship between apparent brain atrophy on the CT brain scans and ACTH-Z treatment. We also discussed the possible etiology of apparent brain atrophy and subdural hematoma, and stressed the necessity of extreme caution with long-term ACTH-Z administration.

Adrenocorticotropic Hormone↗
PubMed1981

The evolution of visual and auditory evoked potentials in infants with perinatal disorder.

The evolutionary changes of evoked potentials (EPs) were studied from the neonatal period up to 1 year of age in 41 infants with various perinatal disorders. Abnormal EPs in the first week of life recovered quickly. In infants with normal outcome, abnormal EPs became normal within a month. In infants with cerebral palsy (CP) or mental retardation (MR), EPs recovered within 2-3 months of age. Infants with more severe neurological damage showed abnormal EPs even beyond 6 months of age. Abnormal EPs beyond 2 weeks of age indicated poor prognosis. As for the wave form of EPs, absent responses or abnormal wave form reflected more severe brain dysfunction. AEPs tended to show more profound abnormalities than VEP. However, some infants with absent AEP in the first week of life had a favorable prognosis. AEPs seemed to be more easily affected by brain dysfunction.

Asphyxia Neonatorum↗
PubMed1981

Development of the motor behavior during sleep in newborn infants.

Body movements during sleep were examined in eight non-eventful preterm babies and two full-term babies using the polygraphic methods including superficial EMG. Typical movements in quiet sleep were startle (St) or generalized phasic movement (GPM) and increased tonic activity in chin muscles. In active sleep, instead of total simultaneous patterns observed in quiet sleep, more un-coordinated and localized movements such as generalized movement (GM), localized tonic movement (LTM), localized phasic movement (LPM) and clonic movement (CM) occurred. Longitudinal study of movements revealed a decrease of St or GPM, GM and LPM. LTM did not decrease with increasing conceptional age. The differences of decreasing tendency among these movements may indicate the differences of maturational changes in the different part of CNS.

Electroencephalography↗
PubMed1981

Prognostic factors of infantile spasms from the etiological viewpoint.

We investigated the prognostic factors for mental and physical development and seizure control by dividing the subjects into various etiologic groups in 200 patients with infantile spasms, all of whom (except 48 who died) were aged six years or older. The results were as follows: 1) Intermediate (4-12 mos) onset was found to be a favorable prognostic factor for seizure control in cryptogenic cases, although there was no relation between the age of onset and prognosis in other etiologic groups. 2) There was a significant correlation between the treatment lag and long-term prognosis for mental and physical development only in cryptogenic cases. A short treatment lag (0-2 mos) was associated with a good prognosis. All cryptogenic patients who had no relapse after ACTH therapy developed normally, although in symptomatic cases, there was no correlation between the relapse and the outcome.

Adrenocorticotropic Hormone↗
PubMed1981

Peripheral neuropathy in Marinesco-Sjögren syndrome.

A case of Marinesco-Sjögren syndrome manifesting cataract, short stature, psychomotor retardation, hypogonadism, and progressive ataxia was described. The result of electrophysiological study reflected the presence of peripheral nerve involvement, which was clearly confirmed by sural nerve biopsy. The conspicuous abnormality observed in the peripheral nerve was the presence of segmental demyelination. The process of axonal degeneration was not remarkable. Results confirmed that Marinesco-Sjögren syndrome is a disorder which may involve both central and peripheral nervous system.

Adolescent↗