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Biomedical subjects

Tetsuo Shimizu

Publications and source records attributed to Tetsuo Shimizu.

At least 73 records · Page 4Linked to original sources
PubMed2002

Physical activity increases the dissociation between subjective sleepiness and objective performance levels during extended wakefulness in human.

The process of heat loss has been shown to be a key pathway regulating sleepiness in humans. The influence of physical exercise with its attending heat production on subjective sleepiness and performance levels during total sleep deprivation (SD) was assessed in eight healthy young volunteers (mean age 21.1 years). Each subject participated in a SD cross-over study in which sleepiness and performance levels were tested under exercise and non-exercise conditions. The exercise entailed 15 min walking/h (3.0 Kcal/kg per h caloric consumption). Physical exercise significantly alleviated subjective sleepiness depending on the magnitude of the core body temperature elevation. This indicates that suppressing heat loss could prevent progression of subjective sleepiness during the nighttime. We found a strong positive correlation between increased sleepiness and decreased performance levels in each of the two experimental sessions. However, ANCOVA revealed a significant difference in the slope of the regression lines representing two sessions, indicating less subjective sleepiness with physical exercise despite the same decrease in performance. The present findings alert us to the possibility that increased physical activity during extended wakefulness could increase the dissociation between subjective evaluation of sleepiness and actual brain function, resulting in increased risk of human error.

Adult↗
PubMed2002

Hypocretin-1 (orexin-A) levels in human lumbar CSF in different age groups: infants to elderly persons.

STUDY OBJECTIVES: Recent CSF and postmortem brain hypocretin measurements in human narcolepsy suggest that hypocretin deficiency is involved in the pathophysiology of the disease. In this study, we measured CSF hypocretin-1 levels in various age ranges from infants to elder people to investigate the age-dependent change of hypocretin concentrations. DESIGN: CSF hypocretin levels were compared by age groups and gender. ANOVA was used to examine the influences of these two parameters on CSF hypocretin levels. SETTING: University-based sleep and biology laboratory. PATIENTS OR PARTICIPANTS: Two hundred seventy two patients were included in this study, with 157 males and 115 females (0-79 years old). INTERVENTIONS: CSF samples were obtained by lumber punctures with informed consents. MEASUREMENTS AND RESULTS: Hypocretin-1 levels are not different in respect to gender or age, although our samples constitute a heterogeneous group with various disease conditions. CSF hypocretin-1 levels in infants under 4 months are similar to those in adults. CONCLUSIONS: Early maturation of hypocretin transmission is suggested. No age- or gender-dependent changes in CSF hypocretin is observed.

Adult↗
PubMed2002

Fluvoxamine augmentation in risperidone-resistant schizophrenia: an open trial.

We investigated the efficacy and safety of augmenting risperidone with fluvoxamine for the treatment of residual positive and negative symptoms in patients with chronic schizophrenia who had shown an incomplete response to risperidone. A total of 30 patients completed the open trial over a 12-week period during which fluvoxamine was added to risperidone. The result from the positive and negative syndrome scale (PANSS) and Simpson-Angus extrapyramidal effects (S-A) scale were examined at baseline, 1, 2, 4, 8 and 12 weeks of treatment. There were no significant differences in PANSS positive, negative and general psychopathology scores, or in S-A scale scores at any point during the treatment. These results suggest that fluvoxamine appears to be ineffective in augmenting the risperidone treatment response in chronic schizophrenic patients. Further controlled trials will be needed to confirm this observation.

Antipsychotic Agents↗
PubMed2002

Influence of the serotonin transporter gene-linked polymorphic region on the antidepressant response to fluvoxamine in Japanese depressed patients.

The presence of the long (l) variant of the serotonin (5-hydroxytryptamine: 5-HT) transporter gene-linked polymorphic region (5-HTTLPR) is reported to be associated with a more favorable and faster antidepressant effect of selective serotonin reuptake inhibitors in Caucasians. The frequency of the l allele is lower in Japanese than in Caucasians; therefore, the antidepressant effect of fluvoxamine can be not as good in Japanese as in Caucasians. The authors investigated whether 5-HTTLPR was associated with the antidepressant response to fluvoxamine in 66 Japanese patients with major depressive disorder in a protocolized-dosing 6-week study. The short (s) allele frequency was significantly higher in the responsive individuals than in the nonresponsive ones (P = .010). The present study suggests that fluvoxamine is not less effective in depressive patients carrying the s allele than in the ones carrying the l allele and it is not less effective in Japanese than in Caucasians.

Adult↗
PubMed2002

Monoamine oxidase: A gene polymorphism, tryptophan hydroxylase gene polymorphism and antidepressant response to fluvoxamine in Japanese patients with major depressive disorder.

Monoamine oxidase A (MAOA) and tryptophan hydroxylase (TPH) are the staple enzymes in the metabolism of serotonin (5-HT). The genetic polymorphisms of these two enzymes might individually alter the production, release, reuptake or degradation of 5-HT during the treatment of selective serotonin reuptake inhibitors (SSRIs), leading to the individual differences in the antidepressant effects of SSRIs. The authors investigated whether a functional polymorphism in the MAOA gene promoter (MAOA-VNTR) and a TPH gene polymorphism in intron 7 (TPH-A218C) were associated with the antidepressant response to fluvoxamine in 66 Japanese patients with major depressive disorder during a 6-week study with a specific dosage plan. Fifty-four patients completed the study. The present study fails to demonstrate that the genetic polymorphisms of MAOA-VNTR and TPH-A218C affect the antidepressant effect of fluvoxamine in Japanese patients with major depressive disorder.

Adult↗
PubMed2002

No association between the serotonergic polymorphisms and incidence of nausea induced by fluvoxamine treatment.

We investigated the association between serotonergic polymorphisms and incidence of nausea, which is the most frequent side-effect of selective serotonin reuptake inhibiters (SSRIs), in 66 patients treated with fluvoxamine in a protocolized-dosing method. We focused on three polymorphisms of serotonin (5-HT) neuronal systems such as 5-HT transporter (5-HTT) gene-linked polymorphic region (5-HTTLPR), a variable number of tandem repeat (VNTR) polymorphism in the second intron of the 5-HTT gene (STin2) and tryptophan hydroxylase (TPH) gene polymorphism in intron 7 (TPH-A218C), which have been reported to possess positive association with treatment response to SSRIs. In addition to this, the relationship between development of nausea and treatment response was also analyzed. Results suggested that these three polymorphisms did not affect the development of fluvoxamine-induced nausea, and that incidence of nausea was not a phenomenon that predicts the treatment response to fluvoxamine.

Adult↗
PubMed2002

PLEDs in Creutzfeldt-Jakob disease following a cadaveric dural graft.

INTRODUCTION: Periodic synchronous discharges (PSDs) are a well-known electroencephalographic finding associated with Creutzfeldt-Jakob disease (CJD), but only a few reports have documented the appearance of periodic lateralized epileptiform discharges (PLEDs) in CJD and there has been no discussion as to why PLEDs appear with unilateral (right or left) dominance. CASE REPORT AND DISCUSSION: We report on a 61-year-old man who received a cadaveric dura mater graft and developed CJD 14 years later. Periodic lateralized epileptiform discharges (PLEDs) were observed predominantly in the right hemisphere, coinciding with the location of the dural graft, the presumed source of the CJD agent and PLEDs seen in this case finally developed into PSDs. A similar case has not been reported in the literature and we believe this case serves to further the understanding of the pathophysiology of CJD.

Creutzfeldt-Jakob Syndrome↗
PubMed2002

CSF hypocretin-1 (orexin-A) concentrations in narcolepsy with and without cataplexy and idiopathic hypersomnia.

We measured cerebrospinal fluid (CSF) hypocretin-1 levels in 11 patients with narcolepsy-cataplexy, five with narcolepsy without cataplexy and 12 with idiopathic hypersomnia (IHS). All patients were Japanese. As reported in Caucasian patients, undetectable or very low hypocretin-1 levels were observed in most (9 out of 11) Japanese narcolepsy--cataplexy patients. Our hypocretin-deficient narcoleptics included three prepubertal cases within few months after the disease onset. All nine hypocretin-deficient patients were human leuckocyte antigen (HLA) DR2 positive, while two who had normal CSF hypocretin-1 levels were HLA DR2 negative. In contrast, none of the narcolepsy without cataplexy and IHS subjects had undetectable low levels. Low CSF hypocretin-1 is therefore very specific for HLA DR2 positive narcolepsy-cataplexy, and the deficiency is likely to be established at the early stage of the disease.

Adult↗
PubMed2002

Hypocretin-1 (orexin-A) concentrations in cerebrospinal fluid are low in patients with Guillain-Barré syndrome.

It is reported that cerebrospinal fluid (CSF) hypocretin-1 (orexin-A) concentrations in patients with narcolepsy are significantly low. Human narcolepsy is also known to be closely associated with a specific human histocompatibility leukocyte antigen (HLA), suggesting that autoimmunity is involved in the pathophysiology of the disease. Thus, it is important to know whether hypocretin changes are found in definite neuroimmunological diseases such as multiple sclerosis and Guillain-Barré syndrome (GBS). The results of the present study indicate that some patients with GBS have lower levels of CSF hypocretin-1.

Analysis of Variance↗
PubMed2002

Effects of Yoku-kan-san-ka-chimpi-hange on the sleep of normal healthy adult subjects.

Yoku-kan-san-ka-chimpi-hange (YKCH) is a drug used for insomnia in Japanese traditional herbal medicine. The present study evaluated the effects of YKCH on sleep by all-night polysomnography using the double-blind method. Yoku-kan-san-ka-chimpi-hange increased the total sleep time significantly, and tended to cause an increase in sleep efficiency and of stage 2 sleep, as well as a decrease of sleep latency and of stage 3 + 4 sleep. There was no apparent influence on rapid eye movement (REM) sleep. In terms of non-REM sleep, the effects of YKCH exhibit a profile similar to those of benzodiazepines.

Adult↗
PubMed2002

Effects of donepezil (Aricept) on the rapid eye movement sleep of normal subjects.

Donepezil (Aricept) is a therapeutic drug for the treatment of Alzheimer's disease (AD). However, there have been only two reports describing the effects of donepezil on sleep as assessed by nocturnal polysomnography (PSG). With this in mind, the effects of donepezil on the sleep of healthy subjects was evaluated using PSG. The results indicated that the percentage of rapid eye movement sleep to total sleep time was increased significantly by a single dose of 5 mg of donepezil when given to healthy subjects immediately before retiring to bed.

Adult↗
PubMed2002

Sleep habits of students attending elementary schools, and junior and senior high schools in Akita prefecture.

It is widely accepted that students in Japan sleep fewer hours than what they actually need. However, epidemiological data on sleep habits among students are scarce. The sleep habits and related problems among 1650 students in Akita prefecture were studied. The results revealed that schoolchildren attending elementary schools seemed to sleep for a sufficient number of hours, whereas students attending junior or senior high schools were not sleeping enough. In particular, approximately half of the students attending senior high schools answered that they slept 6 h or less on weekdays and nodded off during classes more than twice a week.

Adolescent↗
PubMed2002

Association between -1438G/A promoter polymorphism in the 5-HT(2A) receptor gene and fluvoxamine response in Japanese patients with major depressive disorder.

Genetic polymorphism of the serotonin 5-HT(2A) receptor seems to be associated with therapeutic response to selective serotonin reuptake inhibitors (SSRIs). The present study investigated whether a novel -1438G/A polymorphism in the promoter region of the 5-HT(2A )receptor gene is associated with therapeutic response to fluvoxamine (an SSRI) in 66 Japanese patients with major depressive disorder. Fluvoxamine (50 to 200 mg) was administered twice daily for 6 weeks. Fifty-four patients completed this study. The genotype distribution and the allele frequencies showed no significant difference between responders and non-responders. The time-course of the Montgomery-Asberg Depression Rating Scale scores showed no significant difference among -1438G/G, -1438G/A, and -1438A/A genotype groups. The results demonstrated that the -1438G/A promoter polymorphism in the 5-HT(2A) receptor gene was unlikely to have a major role in therapeutic response to fluvoxamine in Japanese patients with major depressive disorder.

Adult↗
PubMed2002

[Nacrolepsy manifesting initially as cataplexy and sleep paralysis: usefulness of CSF hypocretin-1 examination for early diagnosis].

We report a 24-year-old man with narcolepsy initially suffered from cataplexy and sleep paralysis. From May 2000, at age 23 he experienced two kinds of recurrent episodes of weakness without altered consciousness; one was provoked by emotion and excitement, the other occurred spontaneously on onset of sleep without hallucination. He denied having daytime sleepiness and did not experience hypnagogic hallucinations. In July 2000, at our hospital he received the first medical examinations, of which physical and neurological results were unremarkable. A magnetic resonance imaging scan of the brain also gave unremarkable results. The initial diagnosis was epilepsy, and anti-convulsant drugs were begun in August 2000. The weakness episodes were not lessened by the treatment with carbamazepine, sodium valproate or clonazepam, and he was admitted to our clinic in April 2001 for further examinations. Human leukocyte antigen testing was positive for DR15 (DR2) and DQ6 (DQ1). The routine electroencephalographam detected no epileptic discharge or paradoxical alpha blocking. A polysomnogram showed a sleep onset REM sleep period and sleep fragmentation, but there was no apnea or periodic leg movements. A multiple sleep latency test showed a mean sleep latency of 1.8 min and REM sleep in three of five naps. These findings suggested probable narcolepsy, so we examined the hypocretin-1 (orexin A) concentration in his cerebrospinal fluid (CSF). It was below the detection limit of the assay (< 40 pg/mL). The final diagnosis in April 2001 was narcolepsy. Making an initial diagnosis of incomplete or atypical narcolepsy is difficult for clinicians. A delay in diagnosis, however, may produce personal and social problems for narcoleptic patients. We believe that an examination of CSF hypocretin-1 aids in the early diagnosis of narcolepsy.

Adult↗
PubMedDate not supplied

Changes in P300 latency during the early withdrawal period in chronic alcohol-dependent patients: two case reports.

AIMS: The present study focused on changes in P300 of the event-related potential (ERP) in two patients with alcohol dependence recorded throughout their alcohol withdrawal period. RESULTS: As a result of this investigation, the peak latency of P300 in each patient was significantly shorter 2 or 3 days after abstinence from alcohol, when marked neurological manifestations appeared, compared to that of the control obtained from 8 to 10 days after cessation of drinking. CONCLUSIONS: It seems reasonable to conclude that the shortening of P300 latency reflects the enhancement of brain activity during the early withdrawal period and that an investigation of changes in P300 would be helpful to clarify the nature of neural activity in the brain associated with alcohol withdrawal.

Adult↗