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Biomedical subjects

M Shibagaki

Publications and source records attributed to M Shibagaki.

At least 37 records · Page 2Linked to original sources
PubMed1986

Nocturnal sleep in infants with congenital cerebral malformation.

Sleep EEG patterns in 17 infants with cerebral malformations (4 months to 4 years of age) were studied throughout nocturnal sleep and the following results were obtained. Seven cases evidenced normal sleep/wakefulness EEG patterns that could be classified into 6 stages. Ten cases showed abnormal sleep EEG patterns as follows: absence of sleep spindles (n = 7) which included cases of absence of EEG patterns characteristic of wakefulness, NREM sleep and REM sleep (n = 5), no characteristic EEG patterns of stages 1-4 (n = 1) and stages W, 1, 2 and REM (n = 1) and the remaining cases with absence of spindles (n = 1), and spindles with an extremely low incidence (n = 2). Short sleep and long awaking times, and no delta rhythmicity during the night, were noted in 5 out of 17 subjects. A significant decrease of DQ was found in subjects with indistinguishable stages including stages W, 1, 2 and REM, as compared with those patients whose stages were all distinguishable.

Agenesis of Corpus Callosum↗
PubMed1986

Delta and spindle components in compressed spectral array during nocturnal sleep in infants with congenital cerebral malformation.

The correlation between the delta and spindle components in compressed spectral array in 18 infants with congenital cerebral malformation (from 4 months to 4 years of age) was studied throughout nocturnal sleep. In 7 (39%, Group A) out of 18 subjects, periodic changes of delta and spindle rhythm powers were noted in the sleep EEG. In 5 subjects (28%, Group B), delta but not spindle rhythm powers were found, and in the remaining 6 subjects (33%, Group C) neither delta nor spindle rhythm powers were found throughout nocturnal sleep. A significant decrease in the developmental quotient was found in group C as compared with group A.

Brain↗
PubMed1986

Correlation between integrated delta and spindle components during nocturnal sleep in mentally retarded children.

The correlation between the integrated delta and spindle components in 81 mentally retarded children (from 3 months to 12 years of age) was studied throughout nocturnal sleep. In 57 (70%, Group A) out of 81 subjects, periodic changes of delta and spindle rhythm powers were noted in the sleep EEG. In 17 subjects (21%, Group B), delta and no-spindle rhythm powers were found, and in the remaining 7 (9%, Group C) no-delta and no-spindle rhythm powers were found throughout nocturnal sleep. A significant increase in abnormal clinical EEGs was found in groups B and C as compared to group A. A significant decrease in DQ was found in groups B and C as compared to group A. A significant decrease in DQ was also found in group C as compared to group B.

Child↗
PubMed1985

Nocturnal sleep in mentally retarded infants with cerebral palsy.

Sleep EEG patterns in 23 mentally retarded children with cerebral palsy (CP) (from 4 months to 5 years of age) and 39 reference mentally retarded children of no abnormality with the exception of psychomotor retardation (from 4 months to 12 years of age) were studied throughout nocturnal sleep, and the following results were obtained. Eleven CP cases and 30 reference cases evidenced normal sleep patterns that could be classified into 6 stages. Twelve other cases in CP and 9 reference cases showed some abnormal sleep EEG patterns as follows: (i) in CP cases absence of EEG patterns characteristic of wakefulness, NREM sleep and REM sleep without spindles (n = 3); porencephaly with microcephaly (n = 1) and cytomegalovirus infection (n = 2), no characteristic EEG patterns of stages 1-4 without spindles (n = 2); cardiac arrest (n = 1) and agenesis of corpus callosum with lissencephaly (n = 1), absence of REM sleep (n = 1); kernicterus, spindles with an extremely low incidence (n = 5); perinatal anoxia (n = 2), kernicterus (n = 1), Lesch-Nyhan syndrome (n = 1) and cerebral palsy due to unknown etiologies (n = 1), and extreme spindles (n = 1); cerebral palsy due to unknown etiologies, (ii) in reference cases no spindles (n = 2), spindles with an extremely low incidence (n = 6), and extreme spindles (n = 1). Short sleep and long waking times during the night were noted in 4 out of 23 CP subjects; kernicterus (n = 2), agenesis of corpus callosum with lissencephaly (n = 1), and porencephaly with microcephaly (n = 1).(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed1985

Effects of alpha-fluoromethylhistidine on sleep-waking parameters in rats.

Effects of alpha-fluoromethylhistidine (FMH), an irreversible inhibitor of histidine decarboxylase, on the sleep-waking parameters were studied in rats for 24 hours. Intraperitoneal administration of FMH (100 mg/kg) at 11:30 hr resulted in a longer sleep latency compared with the control values. Hour-to-hour analyses revealed that wakefulness (W) time decreased (from 20:00 to 07:00 hr) and slow wave sleep (SS) time increased (from 19:00 to 06:00 hr) in the night. Paradoxical sleep (PS) time did not parallel the SS changes; it was increased significantly from 07:00 to 11:00 hr in the next morning. The influence of FMH seemed to be divided into direct, immediate action (increase of W) and late, prolonged action (decrease of W), and the results obtained support the histamine arousal hypothesis.

Animals↗
PubMed1985

Facilitative effects of maternal environmental enrichment on maze learning in rat offspring.

Pregnant rats were differentially reared in enriched (EC), impoverished (IC), and standard colony conditions (SC) through the pregnancy. Half of the male offspring were reared by their biological mothers and the remaining half were reared by foster-mothers. After weaning male offspring were tested in the Hebb-Williams maze apparatus. The effect of environment was significant for the total error scores; the EC group had less errors than the IC group. In a second experiment all male offspring (EC, SC and IC) were reared by foster-mothers. The effect of environment was significant for initial, repetitive, and total error scores. Further analysis revealed that the EC-SC and EC-IC differences were significant, whereas the IC-SC difference was not. Thus, the results obtained were the first to reveal that maternal environmental enrichment during pregnancy can exert a facilitatory influence on the postnatal maze learning abilities of the offspring.

Animals↗
PubMed1985

Non-linearity of visual evoked potentials in cerveau isolé and midpontine pretrigeminal cats.

Characteristics of the visual evoked responses to the flickering flash stimulation were studied in the cerveau isolé and midpontine pretrigeminal cats. The flash stimulation frequency was changed stepwise between 1 and 30 Hz in increasing and decreasing order. In all cases of both preparations, with drawing of fixed sweep speed of 200 msec in whole length, P1 and N1 latencies in the successive response slightly prolonged progressively 1 to about 20 Hz and thereafter shortened about 20-30 Hz stimulus frequencies in the course of the increasing phase, and vice versa in the course of the decreasing phase. Moreover, no difference in each latency (P1, N1, P2, N2) was found at the same stimulus frequency during increasing and decreasing phases. In the amplitude taken from the P1-N1 component, the peak was found in 5-9 Hz frequency bands. This peak was higher during the decreasing phase than during the increasing phase, which indicated a hysteresis phenomenon. A peak of power for the 1st harmonics was found at 3-6 Hz driving frequency bands, and that of the 2nd harmonics at 6-10 Hz. In the state without flash stimulus, no peaks or valleys in the power spectrum were found in specific frequencies, for example 3-10 Hz. The peak in the amplitude and that in the power spectrum at 3-10 Hz stimulus frequency bands suggested an entrainment phenomenon induced by forced oscillation. The phenomena of entrainment and hysteresis suggest the existence of a non-linear structure in the oscillation generating systems of visual evoked response.

Animals↗
PubMed1985

Changes in the reticuloendothelial phagocytic function after partial hepatectomy.

The changes in the phagocytic function of the reticuloendothelial (RE) system after 67% hepatectomy in rats were studied by use of 51Cr-endotoxin as the phagocytable material. The humoral opsonic index was significantly increased to approximately 1.2 to 1.8 (control, 1.0 +/- 0.2, mean +/- SD) until the fourteenth postoperative day. In contrast, the phagocytic index was decreased to 0.068 +/- 0.016 (control, 0.103 +/- 0.015) on the first day, then returned to the normal level on the second day. In this early postoperative period, uptake rates of 51Cr-endotoxin in the liver were remarkably decreased to about 50% to 70% of control, whereas those in the spleen and lung were increased two- to threefold of control. From the third to the fourteenth day, the phagocytic index was significantly increased compared with the preoperative level. During this period, the uptake rates in the liver and spleen were within the normal range. These results suggest that the increases in the opsonic index of 67% hepatectomized rats represent the homeostatic response for maintaining or stimulating RE system phagocytic function, and that high or normal phagocytic index, concomitant with the increase in the opsonic index, implies an enhanced or compensatory stage, respectively. The decrease in the phagocytic index despite the high opsonic index is assumed to represent a compromised stage of the RE system.

Animals↗
PubMed1985

[Stage-classification of reticuloendothelial function in hepatic injuries in the rat].

The serial changes of RE function were classified into 3 stages according to changes in opsonic activity and phagocytic index in hepatectomized, CCl4-treated cirrhotic rats; enhanced stage, compensating stage and critical stage. The phagocytic index was measured by initial disappearance rate after 4 mg/kg i.v. injection of 51Cr-labelled LPS. An opsonic activity was determined by the bioassay method using cultured RE cells prepared from the normal rat liver. The enhanced stage was characterized by an enhancement in both phagocytic index and opsonic activity--3 to 21 day-70% hepatectomized, 2 to 5 day-40% hepatectomized, 3 week-cirrhotic rats. The compensating stage by increased opsonic activity and normal phagocytic index was 2 day-70% hepatectomized and 9 week-cirrhotic rats. The critical stage by decreased phagocytic index was 5 hour to 1 day-70% hepatectomized, 13 week-cirrhotic rats.

Animals↗
PubMed1985

Skin potential responses of mentally retarded children during nocturnal sleep.

Skin potential responses (SPRs) of 38 mentally retarded children were studied during their nocturnal sleep. One subject exhibited no SPRs; 19 of the 37 subjects showed more SPRs (Type A); 11, no predominant ones (Type B); and 7, fewer SPRs (Type C) during quiet sleep (no rapid eye movements, NREM sleep) than in active sleep (REM sleep). Types B and C tended to be observed more frequently for subjects with abnormal clinical EEGs than for those with normal clinical EEGs. Because investigators have established that nonretarded subjects of 3 months and over exhibit Type A, SPRs may be used as an additional assessment for diagnosis of mental retardation in early infancy.

Child↗
PubMed1985

Nocturnal sleep of severely mentally retarded children and adolescents: ontogeny of sleep patterns.

The development of nocturnal sleep of 79 mentally retarded children and adolescents (from 6 months to 20 years of age) was studied. Polygraphic recordings were carried out while the subject was in bed, and routine sleep parameters were measured. Total sleep time and percentage of Stage REM (rapid eye movements) decreased and awake time tended to increase with age. These values were similar to those previously found for age-matched nonretarded subjects. Results showed that the basic function of the sleep-waking system of retarded children seems to develop normally with age.

Adolescent↗
PubMed1984

Cyclic variation of integrated spindle components during nocturnal sleep in mentally retarded children.

The cyclic variation of the integrated spindle component in 77 mentally retarded children (from 3 months to 12 years of age) was studied throughout nocturnal sleep. In 31 out of 77 subjects high integrated spindle rhythm power was noted in the sleep EEG. In 24 subjects, low integrated spindle rhythm power was found, and in the remaining 22 subjects no integrated spindle rhythm power was noted throughout nocturnal sleep. There was a significant increase in abnormal clinical EEGs in subjects with no spindle rhythm power as compared to those with high and low spindle rhythm powers. A significant decrease in DQ was found in the subjects with no spindle rhythm power as compared to those with high and low spindle rhythm powers.

Brain↗
PubMed1983

Minimal requirement of the remnant pancreas for protein and DNA synthesis of cultured hepatocytes prepared from pancreatectomized rats.

The incorporation of 3H-thymidine and 3H-leucine into the hepatocytes was studied, using cultured hepatocytes prepared from normal and pancreatectomized rats. (1) In the cultured hepatocytes prepared from 80% pancreatectomized rats, the incorporation of 3H-thymidine and 3H-leucine into hepatocytes remained unchanged compared with those of sham-operated controls. In contrast, in those from totally pancreatectomized rats, the incorporation of 3H-thymidine and 3H-leucine decreased to approximately 67% and 37% respectively of sham-operated controls. However, those returned to near normal in the cultured hepatocytes from totally pancreatectomized rats treated by 0.8 IU/kg of insulin. (2) The addition of insulin (10(-4) M) to the culture medium stimulated the incorporation of 3H-thymidine into cultured hepatocytes prepared from normal rats to 148% of controls. The insulin-stimulated incorporation was inhibited by the addition of glucagon to the culture medium. The combined addition of insulin and glucagon did not synergistically act on DNA synthesis. It is suggested that the portal blood insulin in the presence of more than 20% of the pancreas is imperative for maintaining spontaneous regeneration.

Animals↗
PubMed1983

Cyclic variation of integrated delta components during nocturnal sleep in mentally retarded children.

The cyclic variation of the integrated delta component in 80 mentally retarded children (from 2 months to 12 years of age) was studied throughout nocturnal sleep, and the following results were obtained. In 62 out of 80 subjects the high integrated delta rhythm power was noted in sleep EEG. In 11 out of the 80, low integrated delta rhythm power was found. In the remaining 7 subjects, no integrated delta rhythm power was found throughout nocturnal sleep. A significant increase in abnormal clinical EEG was found in subjects without delta rhythm power as compared to those with high delta rhythm power. A significant decrease in DQ was found in the subjects without delta rhythm power as compared to those with high and low delta rhythm powers.

Brain↗
PubMed1983

The first phase of nocturnal sleep in mentally retarded children.

The first phase of sleep observed in 104 mentally retarded children (from 3 months to 8 years of age) was studied throughout nocturnal sleep, and the following results were obtained. In 4 out of 104 subjects, REM sleep onset was observed, and in the remaining 100 subjects NREM sleep onset was found at the first wakefulness-sleep transition of the night. Following awakenings (lasting 4 min or more) during the night, 170 (51.7%) out of a total of 329 samples were REM sleep onset, and 159 (48.3%) showed NREM sleep onset. The phases of sleep onset and those following awakenings evidenced no correlation between the frequency of NREM sleep onset and DQ or clinical EEG, whereas a positive correlation was found between the frequency of NREM sleep onset and age.

Child↗
PubMed1983

Respiratory pauses and apnea during nocturnal sleep in mentally retarded infants.

Respiratory pauses (ResP), apnea (Ap) and periodic respiration (PerR) observed in 42 mentally retarded infants (from 9 to 50 weeks of age post term) were studied throughout nocturnal sleep. All subjects had ResP in the recordings. The range of ResP rates was 4.1-42.1/h, and the mean was 13.5/h. Ap occurred in 22 out of 42 subjects. The range of Ap occurrence (10-15 sec duration) among subjects was 1-10, with a mean of 4.1. Moreover, in 4 out of 22 subjects, Aps of greater than 15 sec duration were seen. In 30 out of 42 subjects, PerR occurred. The range of occurrence of PerR among subjects was 1-35, and the mean was 9.6.

Child↗