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Biomedical subjects

K Hara

Publications and source records attributed to K Hara.

At least 1,207 records · Page 67Linked to original sources
PubMed1980

The evolution of some EEG features in normal and abnormal infants.

Evolutionary changes of EEG up to one year in 81 infants followed from neonatal periods were studied. Tracé alternant (TA) disappeared at 1-2 months in infants with normal outcome and those with cerebral palsy (CP or mental retardation (MR). In patients with CP & MR or those with CP & MR & epilepsy (EP), the time when TA disappeared was delayed. Presence of TA at or beyond 2 months suggests severe brain damage such as CP & MR, or CP & MR & EP. The spindle appeared within 3 months in normal infants and those with CP, but in some patients with CP & MR, or those with CP & MR & EP, no spindle ever appeared. The delay of its appearance beyond 3 months in considered to be an unfavorable sign. There is a very good correlation between neonatal background EEGs and the time of disappearance of TA and spindle appearance. The abnormal background EEGs after the first month suggested severe damage, and no specificity such as might reflect a certain type of developmental disability was found.

Age Factors↗
PubMed1980

Guillain-Barré syndrome presenting with signs of ophthalmoplegia.

Two cases of Guillain-Barré syndrome (GBS) presenting with signs of ophthalmoplegia were reported. One showed unilateral internal ophthalmoplegia without external ophthalmoplegia, and the other displayed partial external ophthalmoplegia with sluggish pupillary response to light. It is important to keep in mind the possibility of GBS with acute onset of internal and/or external ophthalmoplegias.

Child↗
PubMed1980

A cytoplasmic clock with the same period as the division cycle in Xenopus eggs.

In most species the cell cycle is arrested in the unfertilized egg. After fertilization the cell cycle is reestablished and a rapid series of cleavages ensues. Preceding the first cleavage in Xenopus the egg undergoes a contraction of its cortex, called the "surface contraction wave," which can be visualized by time-lapse cinematography. This wave of contraction is propagated in a circular manner from the animal pole to the equator. We have found that eggs prevented from cleaving by treatment with antimitotic drugs undergo a sequence of periodic surface contraction waves timed with the cleavage cycle in untreated eggs. In addition, artificially activated eggs, which fail to cleave presumably for lack of a functioning centriole, undergo the same periodic contractions. No nuclear material is required for the periodic waves because a separated egg fragment, produced by constricting a fertilized egg, still undergoes contraction waves with the same period as the cleaving nucleated fragment. These results demonstrate that some expression of the cell cycle persists in the absence of any nuclear material or centrioles, suggesting to us that a biological clock exists in the cytoplasm or cortex of vertebrate eggs, which may be involved in timing the cell cycle.

Animals↗
PubMed1980

The role of perinatal brain injury in the genesis of childhood epilepsy.

In order to elucidate the significance of perinatal brain damage in the etiology of epilepsy, 139 full-term neonates considered to have suffered a severe degree of perinatal hypoxia were examined neurologically and electroencephalographically for two-nine years. Thirty-eight (27.3%) of them developed epileptic seizures during the follow-up period. Sixteen infants developed infantile spasms at ages two-13 months, while 10 manifested generalized motor seizures mainly at one-four years. They all had neonatal background EEGs suggesting a severe degree of brain damage, although the infants with infantile spasms and myoclonic seizures showed more abnormal neonatal EEGs than those with other types of fits. The combination of multiple factors, mainly exogenous and constitutional, is necessary for the development of epileptic seizures, especially in patients with a lesser degree of brain damage.

Birth Injuries↗
PubMed1980

[Effects of ultrasonic irradiation on chromosomes, cell division and developing embryos (author's transl)].

These experiments were planned to acquire any informations about the possibilities of harmful effects of ultrasonics on the chromosomes, the cell division of cultured cells and the developing embryos of the ICR mice. 1. The effects of ultrasonics on the chromosomes. Lymphocytes of fetal blood, fibroblasts of fetal skin and fibroblasts from amniotic fluid were exposed to the continuous ultrasonics of 2MHz with the intensity of 2W/cm2, 1 hour. No significant increase of chromosomal aberrations was found in the exposed groups. 2. The effects on the growth of cultured cells. Fibroblasts of fetal skin were exposed to the continuous ultrasonics of 2MHz (max 2MHz, 2 hours). The cell growth was observed during 14 days, but no suppression on the cell division appeared in the exposed groups. 3. The effects on the ICR pregnant mice. In total, 125 ICR pregnant mice were exposed to the ultrasonics of 2MHz on 8th day of pregnancy (I; control group, II; buffered control group, III; 200 mw/cm2 and IV; 2000 mw/cm2, 5 min). The weight gain of maternal body was suppressed in group IV. The number of implantation sites in group IV was significantly higher than the other 3 groups. The external, skeletal and visceral abnormalities were examined for 1251 fetuses. Brain hernia, anencephaly, cleft palate and skeletal abnormalities were found in group IV and its incidence was significantly higher than the other 3 groups.

Animals↗