Biomedical subjects

M Shibagaki

Publications and source records attributed to M Shibagaki.

At least 19 recordsLinked to original sources

PubMed2001

Cambial reactivation in locally heated stems of the evergreen conifer Abies sachalinensis (Schmidt) masters.

A study was made of cambial activity, the localization of storage starch around the cambium, and the localization and occurrence of microtubules in cambial cells from dormancy to reactivation in locally heated (22-26 degrees C) stems of the evergreen conifer Abies sachalinensis. Heating induced localized reactivation of the cambium in the heated portions of the stem. Erect ray cambial cells resumed cell division 1 d prior to the reactivation of fusiform cambial cells and procumbent ray cambial cells. The re-initiation of the division of fusiform cambial cells occurred first on the phloem side. During the heat treatment, the amount of storage starch decreased in procumbent ray cambial cells and in the phloem parenchyma adjacent to the cambium but increased in fusiform cambial cells. Preprophase bands of microtubules, spindle microtubules and phragmoplast microtubules were observed both in erect ray cambial cells and in procumbent ray cambial cells. By contrast, no evidence of the presence of such preprophase bands of microtubules was detected in fusiform cambial cells. The results suggest that the localized heating of stems of evergreen conifers might provide a useful experimental model system for studies of the dynamics of cambial reactivation in intact trees.

Cycadopsida↗

PubMed2001

Heart-rate variability during nocturnal sleep in mentally retarded children.

Heart-rate variability in four normal and 30 mentally retarded children was investigated during nocturnal sleep. In four normal and 25 mentally retarded subjects, a high frequency component defined as spectral activity between 0.15 and 0.5 Hz was found in the compressed spectral array of the power spectra. A periodic change was seen in the high frequency component which corresponded precisely to the sleep cycle. However, four children with mental retardation did not show normally expected changes in the high frequency components specific to the sleep stages: a quantity of the high frequency component in only one sleep cycle (n=2; 6 mo. and 3 yr., 8 mo.), a decreased quantity and discontinuity of the high frequency component in only the second sleep cycle (n=1; 1 yr., 2 mo.), and no high frequency component in any sleep cycle (n=1; 3 mo.) These findings suggest that some mentally retarded children have an abnormal parasympathetic nervous activity.

Adolescent↗

PubMed1997

Baseline respiratory sinus arrhythmia and heart-rate responses during auditory stimulation of children with attention-deficit hyperactivity disorder.

During passive and active listening tasks baseline respiratory sinus arrhythmia and heart-rate responses were studied of 18 children with Attention-Deficit Hyperactivity Disorder (ADHD) and 49 healthy school children. The experimental procedure included baseline recording (no task), a passive listening task, instructions, and both simple and discriminative active-listening tasks. ADHD subjects showed less respiratory sinus arrhythmia than normal children but were similarly responsive to tone stimuli.

Acoustic Stimulation↗

PubMed1994

Use of running exercises for preschoolers with mental retardation as a means of improving play or school activity.

Various physical training programs have been devised to achieve greater physical fitness for handicapped children who otherwise exercise insufficiently. Such training may also facilitate socializing and play at school. Running exercises were conducted with 4 handicapped preschoolers and 3 age-matched normal preschoolers for 3 30-min. sessions per week for 11 weeks. Measures were seconds taken to run 25 meters and ratings of play behavior. Analysis showed that children who reluctantly joined the exercise made little progress in running. The quality of movement and play activities in nursery school and interactive behavior improved significantly for participants who also improved in running.

Attention↗

PubMed1994

Age differences in characteristics of the attention process of electrodermal activity during auditory stimulation.

Age differences in characteristics of the attention process of electrodermal activity during passive and active listening tasks were studied with 43 nursery and 49 primary school children and 38 university students. The procedure included baseline recording, a passive listening task, instruction, and an active listening task. Significant differences in skin conductance response (SCR) were found among the three age groups. The SCR became smaller for the groups of increasing ages only for the active listening task. As the trials progressed, there was a trend in the three age groups for decreasing SCR amplitude during the passive listening task.

Adolescent↗

PubMed1993

Antipromoting effects of 5-lipoxygenase inhibitors, 3-nitro-2,4,6- trihydroxybenzamide derivatives, on TPA-promoted transformation in BALB 3T3 cells.

In order to discover the role in the promotion process of 5-lipoxygenase (5-LO), a key enzyme in the arachidonate cascade, the antipromoting effects of the 5-LO inhibiting 3-nitro-2,4,6-trihydroxybenzamide (NTB) derivatives were studied in a two-stage transformation assay system using BALB 3T3 cells. All compounds inhibited TPA-promoted transformation in a dose-dependent manner. Most of them achieved a 70-80% inhibition. Good correlations were observed between the inhibition of TPA-promoted transformation and that of 5-LO. These results indicate that 5-LO plays an important role in the promotion stage of the transformation of BALB 3T3 cells.

3T3 Cells↗

PubMed1993

Inhibitory effects of 3-nitrophloroglucinecarboxylic acid derivatives on Epstein-Barr virus early antigen induction.

The inhibitory effects of two series of 3-nitrophloroglucinecarboxylic acid derivatives, 3-nitro-2,4,6-trihydroxythiobenzamides (II) and 3-nitro-phloroglucinecarboxylates (III), on Epstein-Barr virus early antigen (EBV-EA) induction were examined using Raji cells. Some of them strongly inhibited the induction, N-nonyl and O-decyl derivatives being the most potent inhibitors among the thioamides and esters, respectively. These results suggest the possibility that these two 3-nitrophloroglucinecarboxylic acid derivatives may be listed as novel inhibitors of tumor promotion.

Antigens, Viral↗

PubMed1993

Attention state in electrodermal activity during auditory stimulation of children with attention-deficit hyperactivity disorder.

Electrodermal activity during passive and active listening tasks of 18 children with Attention-Deficit Hyperactivity Disorder (ADHD) and 49 healthy school children was studied. The procedure included baseline recording, a passive listening task, instructions, and both simple and discriminative active-listening tasks. ADHD subjects tended to exhibit lower arousal as indicated by the decrease in amplitude of the skin conductance response. Present findings confirm classical observation that ADHD children have shorter attention spans.

Acoustic Stimulation↗

PubMed1992

Effects of attention state on electrodermal activity during auditory stimulation of children.

During passive and active listening tasks electrodermal activity of 49 healthy school children was studied. The procedure included baseline recording, a passive listening task, instructions, and simple and discriminative active-listening tasks. On the passive task from Trials 1 to 10, habituation of the amplitude of the skin conductance response (SCR) occurred. Habituation of SCR amplitude did not occur during the active tasks. The children seemed to pay more attention during the active tasks than during the passive task, since the need to press the key is apt to require and may even increase general attention. As for temporal variables of SCR, the frequency of spontaneous SCRs showed a significant negative correlation with SCR latency and rise time. Reaction time exhibited a significant negative correlation with age. An increase in reaction time was found during the discriminative active-listening task over that for the simple active-listening task during the course of 10 trials. The younger children (6-8 yr.) seemed to require longer to pay attention than the older ones (10-12 yr.). Children seemed to pay more attention during the discriminative than during the simple active-listening task, since the need to press the key for discrimination should require and is likely to increase general attention.

Arousal↗

PubMed1991

Inhibitory effects of 3-nitro-2,4,6-trihydroxybenzamides on Epstein-Barr virus early antigen induction.

Inhibitory effects of a series of 3-nitro-2,4,6-trihydroxybenzamides on Epstein-Barr virus early antigen (EBV-EA) induction were examined using Raji cells. Some of the tested compounds showed highly inhibitory activity, the N-octyl amide derivative being the most active among them. These results suggest the possibility that 3-nitro-2,4,6-trihydroxybenzamides might be listed as novel inhibitors of tumor promotion.

Antigens, Viral↗

PubMed1991

Attention of preschool children: temporal variation of electrodermal activity during auditory stimulation.

Temporal variation of electrodermal activity during passive and active listening tasks of 43 healthy preschool children was studied. The procedure included the baseline recording, a passive listening task, instruction, and an active listening task. The frequency of spontaneous skin-conductance responses (SCRs) showed a significant negative correlation with SCR latency and rise time. Mean SCR amplitude, moreover, displayed a significant negative correlation with the SCR latency and rise time. Reaction time exhibited a significant negative correlation with age. A decrease in the SCR latency was noted during the active listening task below that for the passive listening task over 10 trials. The children seemed to pay more attention as SCR latency and rise time decreased, and the younger children seemed to pay attention later than the older ones. Children seemed to pay more attention during the active than during the passive listening tasks, since the need to press the key should require and perhaps increase general attention.

Age Factors↗

PubMed1990

Attention of preschool children: electrodermal activity during auditory stimulation.

Electrodermal activity during passive and active listening tasks of 43 healthy preschool children (aged 4 yr., 8 mo. to 6 yr., 5 mo.) was studied. The procedure included the following phases: baseline recording (3 min.), a passive listening task, instructions, and an active listening task. An increase in mean amplitude of skin conductance response (SCR) was found during the active listening task over the level for the passive listening task over 10 trials. On the passive listening task from Trial 1 to Trial 10, habituation of mean SCR amplitude occurred. The younger children, moreover, exhibited significantly greater habituation than the older children. Habituation of mean SCR amplitude did not occur during the active listening task. No significant difference was found in mean SCR amplitude during the active listening task for the two age groups. The children seemed to pay more attention during the active listening task than during the passive listening task. The younger children, moreover, are believed to have shorter attention spans.

Arousal↗

PubMed1990

Attention of hyperactive preschool children--electrodermal activity during auditory stimulation.

Electrodermal activity during passive and active listening tasks for 4 hyperactive (from 3 yr., 9 mo. to 6 yr., 2 mo.) and 43 healthy preschool children (from 4 yr., 8 mo. to 6 yr., 5 mo.) was studied. The procedure consisted of the following phases: baseline recordings (3 min.), a passive listening task, instructions, and an active listening task. The hyperactive subjects tended to exhibit lower levels of arousal, as indicated by the frequency of spontaneous responses, and more marked habituation with repeated stimuli. Also, they tended not to show the increased responsivity expected when attention is active rather than passive. Hyperactive preschool children, moreover, are believed to have shorter attention spans.

Arousal↗

PubMed1988

The three different phases of reticuloendothelial system phagocytic function in rats with liver injury.

In the present study, reticuloendothelial system (RES) phagocytic function of rats with partial hepatectomy or experimentally induced liver cirrhosis was investigated by determining the phagocytic index, the opsonic index, and uptake rate in liver, spleen, and lung of a 51Cr-labeled endotoxin-injected rat. In both the partially hepatectomized and the cirrhotic rats, all three indicators varied markedly according to the elapsed period since liver injury. The changes in RES phagocytic function were classified into three different phases: compromised, compensatory, and enhanced. The compromised phase, consisting of a decrease in the phagocytic index, was observed during the first 24 hr after 67% hepatectomy and in advanced liver cirrhosis. This represented the failure of RES phagocytic function. The compensatory phase, in which the phagocytic index was maintained at nearly normal levels mainly by a compensatory enhancement in the opsonic index, was seen during the first to second postoperative day and in moderate liver cirrhosis. The enhanced phase, with a high phagocytic index, was observed from Day 4 to approximately Day 14 after surgery, and in the cases of mild liver damage. In the compromised and compensatory phases, the liver uptake rate was significantly decreased compared with the control. However, the uptake in the spleen and lung were markedly increased. In conclusion, the phagocytic function of the RES was significantly affected to a degree which changed with the extent of liver damage.

Animals↗

PubMed1987

REM sleep latency during nocturnal sleep in mentally retarded infants.

REM sleep latency observed in 61 mentally retarded infants (4-13 months of age) was studied throughout nocturnal sleep. Mentally retarded infants revealed a J distribution of short (less than 8 min) and long (more than 8 min) REM sleep latencies. This feature of distribution was similar to that obtained by other authors from normal infants under 3 months of age. REM sleep latency did not depend on the duration of prior wakefulness. Long REM sleep latencies were no more often preceded by long episodes of wakefulness than were short REM sleep latencies. No correlation was found between REM sleep latency and age, developmental quotient or daytime clinical EEG abnormalities.

Aging↗

PubMed1987

Developmental disorders of skin potential responses in mentally retarded children during nocturnal sleep.

Skin potential responses (SPRs) of 89 mentally retarded children were studied during their nocturnal sleep. Forty-three out of the 89 subjects showed more SPRs (type A) during NREM sleep than in REM sleep. The opposite was observed in 10 cases (type C), and 4 had evenly distributed SPRs during both sleep phases (type B). The remaining 32 subjects had mixed types AB (n = 19), AC (n = 6) or BC (n = 7). Types B and C (including the mixed type) were observed more frequently for subjects with low developmental quotient (DQ) and abnormal clinical EEGs than for those with high DQ and normal clinical EEGs. Since it has been well established that normal subjects of 3 months and over exhibit exclusively type A, SPRs may be used as an additional tool for the diagnostic assessment of mental retardation in early infancy.

Adolescent↗

PubMed1987

Correlation between delta and spindle components in compressed spectral array during nocturnal sleep in mentally retarded children.

The correlation between the delta and spindle components in compressed spectral array in 96 mentally retarded children (from 3 months to 12 years of age) was studied throughout nocturnal sleep. In 57 (59.4%, group A) of 96 subjects, periodic changes of delta and spindle rhythm powers were noted in sleep EEG. In 29 subjects (30.2% group B), delta but not spindle rhythm powers were found, and in the remaining 10 subjects (10.4%, group C) neither delta nor spindle rhythm powers were found throughout nocturnal sleep. A significant increase in abnormal clinical EEG was found in groups B and C as compared with group A. A significant decrease in the developmental quotient (DQ) was found in groups B and C as compared with group A. A significant decrease in DQ was also found in group C as compared with group B.

Child↗

PubMed1986

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

The correlations between the delta and spindle components in compressed spectral array in 21 mentally retarded children with cerebral palsy (CP) (from 4 months to 5 years of age) and 32 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. In 11 (52%) out of 21 CP cases and 27 (84%) out of 32 reference cases, periodic changes of delta and spindle rhythm powers were noted in sleep EEG (group A). In 5 (24%) other cases in CP and 5 (16%) reference cases delta but not spindle rhythm powers were found (group B), and in the remaining 5 (24%) CP cases neither delta nor spindle rhythm powers were found throughout nocturnal sleep (groups C). A significant decrease in the developmental quotient (DQ) was found in group C as compared with group A in both CP and reference cases. Moreover, a significant decrease in DQ was also found in group B as compared with group A of reference cases.

Cerebral Palsy↗