Search PubMed⌕ Search

Biomedical subjects

Tetsuo Shimizu

Publications and source records attributed to Tetsuo Shimizu.

At least 19 recordsLinked to original sources
PubMed2004

Similar profiles in human period1 gene expression in peripheral mononuclear and polymorphonuclear cells.

Increasing amounts of data have indicated the physiological significance of circadian clock gene regulation in various peripheral cells. In the present study, we examined expression of the human homolog of period1 (hPer1) in peripheral mononuclear cells (MNCs) and polymorphonuclear neutrophils (PMNs) in seven healthy young male volunteers (mean age, 21.0 years; range, 19-24 years) under modified constant routine conditions. The expression of hPer1 as determined by real-time PCR with gene-specific hybriprobes in MNCs and PMNs showed significant daily variations with similar acrophases and peak transcription in the subjective morning. The acrophases in hPer1 expression rhythms in MNCs and PMNs were found to correlate positively with that of the serum melatonin secretion rhythms, which is a reliable phase marker of the suprachiasmatic nucleus (SCN), the circadian master clock. The present findings indicate that clock gene activity could be preserved across different peripheral blood cell types and support the assumption that peripheral clocks are entrained by the SCN.

Adult↗
PubMed2004

Diazepam reduces both arterial blood pressure and muscle sympathetic nerve activity in human.

It is known that benzodiazepines have a hypotensive effect, but the mechanism has not been well elucidated yet. To clarify whether this effect is due to central or peripheral mechanism, we administered 5 mg of diazepam or saline intravenously to healthy volunteers and assessed the change in blood pressure, heart rate, muscle sympathetic nerve activity and heart rate variability. After diazepam administration, systolic and mean blood pressure decreased significantly. Muscle sympathetic nerve activity was also significantly reduced but heart rate did not change, whereas the variables of spectral analysis of heart rate variability did not show significant change. We concluded that the hypotensive effect of diazepam in human is mainly due to the central mechanism.

Action Potentials↗
PubMed2004

Prediction of antidepressant response to milnacipran by norepinephrine transporter gene polymorphisms.

OBJECTIVE: With a multitude of antidepressants available, predictors of response to different classes of antidepressants are of considerable interest. The purpose of the present study was to determine whether norepinephrine transporter gene (NET) and serotonin transporter gene (5-HTT) polymorphisms are associated with the antidepressant response to milnacipran, a dual serotonin/norepinephrine reuptake inhibitor. METHOD: Ninety-six Japanese patients with major depressive disorder were treated with milnacipran, 50-100 mg/day, for 6 weeks. Severity of depression was assessed with the Montgomery-Asberg Depression Rating Scale. Assessments were carried out at baseline and at 1, 2, 4, and 6 weeks of treatment. The method of polymerase chain reaction was used to determine allelic variants. RESULTS: Eighty patients completed the study. The presence of the T allele of the NET T-182C polymorphism was associated with a superior antidepressant response, whereas the A/A genotype of the NET G1287A polymorphism was associated with a slower onset of therapeutic response. In contrast, no influence of 5-HTT polymorphisms on the antidepressant response to milnacipran was detected. CONCLUSIONS: The results suggest that NET but not 5-HTT polymorphisms in part determine the antidepressant response to milnacipran.

Adrenergic Uptake Inhibitors↗
PubMed2004

A case of mild Alzheimer's disease accompanied by periodic synchronous discharges.

Periodic synchronous discharges (PSD) on the electroencephalogram can be observed in diseases such as Creutzfeldt-Jakob disease, hypoxic encephalopathy and Alzheimer's disease (AD). However, in previously reported cases of AD with PSD, PSD have only been found many years after the diagnosis of AD. We recently encountered a patient with mild AD accompanied by transient PSD. To our knowledge, this is the first case report to suggest that PSD can occur in mild AD.

Aged↗
PubMed2003

Total sleep deprivation elevates blood pressure through arterial baroreflex resetting: a study with microneurographic technique.

STUDY OBJECTIVES: Sleep deprivation has a profound effect on cardiovascular regulation through the autonomic nervous system. This study examined the effect of 24-hour total sleep deprivation on muscle sympathetic nerve activity (MSNA), which is a direct measurement of the postganglionic sympathetic efferent innervating the vascular bed in the skeletal muscle and other circulatory structures. DESIGN: The study was performed on 6 young healthy men. The factors exerting influence on MSNA, such as aging, obesity, body posture, activity, intensity of illumination, and food and beverage consumption were strictly controlled. Burst rate and burst incidence were used as parameters of MSNA. The burst rate, burst incidence, heart rate, and systolic and diastolic blood pressure were measured after total sleep deprivation and control sleep. To perform a linear regression analysis of arterial baroreflex (ABR), the incidence of MSNA bursts corresponding to a given diastolic blood pressure (%MSNA) was examined. MEASUREMENT AND RESULTS: The diastolic blood pressure was significantly higher after total sleep deprivation than after control sleep (66.5 +/- 1.7 vs 57.4 +/- 3.3 mm Hg). The burst rate (9.6 +/- 1.8 vs 13.3 +/- 2.7 bursts/min) and burst incidence (21.6 +/- 4.5 vs 30.3 +/- 8.9 bursts/100 heart beats) of MSNA were significantly lower after total sleep deprivation than after control sleep (P < .05). Analysis of the ABR disclosed a significant linear regressive relation between %MSNA and diastolic blood pressure in every subject after both total sleep deprivation and control sleep. This result implies that the ABR regulates the occurrence of MSNA bursts under different diastolic blood pressure conditions. The threshold (X-axis intercept) of the blood pressure regression line (ie, an indicator of the ABR set point) shifted by 12 +/- 4.3 mm Hg toward a higher blood pressure level after total sleep deprivation (P < .05). The ABR sensitivity, or the slope of the regression line, tended to be less steep after total sleep deprivation than after control sleep, although it was not statistically significant (P = .09). CONCLUSIONS: The diastolic blood pressure increased and both burst rate and burst incidence of MSNA decreased after total sleep deprivation. The results show that resetting of the ABR toward a higher blood pressure level occurred after total sleep deprivation. This ABR resetting probably brings about an increase in arterial blood pressure after total sleep deprivation.

Adult↗
PubMed2003

The diagnostic and prognostic relevance of human telomerase reverse transcriptase mRNA expression detected in situ in patients with nonsmall cell lung carcinoma.

BACKGROUND: The objectives of this study were to evaluate the diagnostic and prognostic relevance of human telomerase reverse transcriptase (hTERT) detected in situ in patients with nonsmall cell lung carcinoma (NSCLC) and to investigate the possible correlations between hTERT mRNA in NSCLC and the patients' clinicopathologic features, including survival. METHODS: hTERT mRNA was detected by in situ hybridization in 146 samples from patients with NSCLC. The signal intensity of hTERT mRNA expression was evaluated by two independent observers. The expression level was defined subjectively as strong, moderate, or weak. RESULTS: hTERT mRNA was detected mainly in the cytoplasm of tumor cells. It was detected in the cytoplasm of 100% of samples from patients with NSCLC but was not detected in normal lung tissue, except in activated lymphocytes. There was a significant correlation between hTERT mRNA expression and pathologic tumor status, pathologic disease stage (pStage), and Ki-67 labeling index. There was no significant correlation between hTERT mRNA expression and age, gender, pathologic lymph node status (pN), histology, or tumor differentiation. The 5-year survival rates for patients with strong and moderate hTERT mRNA expression levels were 46.9% and 77.9%, respectively; the difference was statistically significant (P = 0.0001). A multivariate analysis of survival using a stepwise procedure revealed that hTERT mRNA expression, pN status, pStage, and age were statistically significant prognostic factors (P = 0.0029, P = 0.0012, P = 0.0237, and P = 0.0496, respectively). CONCLUSIONS: The findings suggested that hTERT mRNA expression may be useful for the diagnosis of NSCLC and also may be an independent prognostic factor for patients with NSCLC.

Adult↗
PubMed2003

Decreased cerebrospinal fluid hypocretin-1 levels near the onset of narcolepsy in 2 prepubertal children.

We present 2 cases of narcolepsy with prepubertal onset. Although excessive daytime sleepiness and cataplexy had appeared early in both patients, the presence of sleep-onset rapid eye movement periods was detected several months after the onset of hypersomnia. The levels of hypocretin in the cerebrospinal fluid were reduced when measured 3 weeks (Patient 1) and 2 months (Patient 2) after the appearance of hypersomnia, before the presence of sleep-onset rapid eye movement periods was confirmed. Because the symptoms of narcolepsy in children are often obscure and easily mistaken as other diseases, and the electrophysiologic studies may not be specific in the early stage, the definite diagnosis tends to be delayed. Measurement of hypocretin-1 levels in the cerebrospinal fluid is useful for the early diagnosis of narcolepsy with prepubertal onset.

Brain↗
PubMed2003

Two pedigrees of familial advanced sleep phase syndrome in Japan.

STUDY OBJECTIVES: To determine whether a known missense mutation (bp2106 A/G) in hPer2 (a human homolog of the Drosophila period gene) for familial advanced sleep phase syndrome in a Caucasian family is involved in Japanese familial advanced sleep phase syndrome pedigrees. MEASUREMENTS AND RESULTS: We identified 2 new Japanese families with advanced sleep phase syndrome, and a systematic survey was carried out in 28 relatives of theses 2 families. A total of 9 affected subjects were identified. The affected members showed significantly strong morningness tendencies compared with the unaffected members in various circadian parameters including the Horne-Ostberg Morningness-Eveningness Questionnaire score (77.3 +/- 4.8 vs 57.5 +/- 7.6, p < 0.001), average sleep-onset time (20:45 +/- 75 min vs 23:16 +/- 64 min, p < 0.02), and average wake time (4:55 +/- 38 min vs 6:13 +/- 25 min, p < 0.01), as well as saliva dim-light melatonin-onset time (20:15 +/- 21 min vs 22:25 +/- 65 min, p < 0.02). DNA samples were obtained from 7 affected and 7 unaffected subjects. None of the tested subjects possessed the missense mutation (bp2106 A/G) in hPer2. Furthermore, there is no significant linkage between affected subjects with hPer2 region by 2-point mapping and by direct sequencing of 23 exons of hPer2. CONCLUSION: These findings support the notion of genetic heterogeneity of familial advanced sleep phase syndrome cases in humans. The search for more familial advanced sleep phase syndrome cases and for loci other than hPer2 are necessary to further examine the roles of circadian-related genes in genetically determined human circadian rhythm disorders.

Adult↗
PubMed2003

Relationship between clinical effects of fluvoxamine and the steady-state plasma concentrations of fluvoxamine and its major metabolite fluvoxamino acid in Japanese depressed patients.

OBJECTIVES: The relationship between clinical effects of fluvoxamine (FLV) and the steady-state plasma concentrations (Css) of FLV and its major metabolite fluvoxamino acid (FLA) was studied. METHODS: The subjects were 49 Japanese patients with major depressive disorder receiving FLV 200 mg/day for 6 weeks. Depressive symptoms and side effects were evaluated by the Montgomery Asberg Depression Rating Scale (MADRS), and the UKU Side Effect Rating Scale, respectively. The Css of FLV and FLA were measured by HPLC, and the CYP2D6 genotyping was performed by PCR methods. RESULTS: The Css of FLV and FLV+FLA showed significant negative correlations with the final MADRS score. The Css of FLV, FLA and FLV+FLA were significantly higher in the responders (final MADRS score < or =10) than in non-responders. The proportion of responders was significantly higher in the patients with the Css of FLV, FLA and FLV+FLA above 150, 55 and 180 ng/ml, respectively. In the multiple regression, the Css of FLV+FLA showed a significant negative correlation with the final MADRS score. In the logistic regression, the Css of FLA had a significant effect on the differentiation of responders from non-responders. The incidence of side effects was low, and the development of nausea, the most frequent one, was not dependent on any Css. The number of mutated CYP2D6 alleles causing absent or decreased enzyme activity was not related to the therapeutic response or development of nausea. CONCLUSIONS: The present study suggests that there is a therapeutic threshold for the Css of FLV and probably also for the Css of FLA, and the Css of FLV+FLA above 180 ng/ml best predicts a good therapeutic response.

Adult↗
PubMed2003

Heat loss, sleepiness, and impaired performance after diazepam administration in humans.

In spite of the accumulation of knowledge regarding the neuropharmacological action of benzodiazepines (Bz), the physiological process by which their sedative/hypnotic effects are induced remains poorly understood. We conducted a single-blind, crossover trial to evaluate the role of the thermoregulatory process in sleepiness and impaired psychomotor performance induced by a standard Bz, diazepam (DZP). Each of the eight healthy young male volunteers (mean age, 19.75 years; range, 18-23 years) was given a single oral dose of either 5 or 10 mg of DZP or placebo 12 h after his average sleep onset time. Changes in plasma DZP concentration, proximal body temperature (p-BT), distal body temperature (d-BT), subjective sleepiness measured by the Visual Analog Scale and Stanford Sleepiness Scale, and psychomotor performance measured by Choice Reaction Time were monitored under a modified constant routine condition in which various factors affecting thermoregulation, alertness, and psychomotor performances were strictly controlled. Orally administered DZP induced a significant transient decrease in p-BT and psychomotor performance as well as an increase in d-BT and subjective sleepiness. Distal-p-BT gradient (DPG; difference between d-BT and p-BT), which is an indicator of blood flow in distal skin regions, showed a strong positive correlation with the plasma DZP concentration, indicating that DZP in clinical doses promotes heat loss in a dose-dependent manner. The DPG also correlated positively with the magnitude of subjective sleepiness and impaired psychomotor performance. These findings indicate that the sedative/hypnotic effects of Bz could be due, at least in part, to changes in thermoregulation, especially in the process of heat loss, in humans.

Administration, Oral↗
PubMed2003

Milnacipran plasma levels and antidepressant response in Japanese major depressive patients.

The relationship between antidepressant effects and plasma levels of milnacipran was studied in 49 cases of major depression without psychotic features during 6 weeks of milnacipran treatment. The daily dose of milnacipran was 50 mg/day for the first week, and up to 100 mg/day thereafter. Depressive symptoms were evaluated by the Montgomery and Asberg depression rating scale (MADRS) before treatment and at 1, 2, 4 and 6 weeks after the beginning of this study. Thirty-four patients (69.4%) were responders (defined as a 50% or greater decrease in the baseline MADRS score). Significant differences of MADRS scores were seen from 1 week after the beginning of this study (p=0.004, unpaired t-test) between responders and nonresponders. The mean plasma milnacipran level of responders, 82.0 +/- 29.4 ng/ml, was similar to that of non-responders, 78.6+/-23.1 ng/ml; there was no significant difference between responders and nonresponders. Neither a significant linear nor a curvilinear relationship was obtained between the final MADRS score and the plasma levels of milnacipran. Although there was no significant relationship between the plasma levels of milnacipran and the antidepressant response, milnacipran should be considered an efficacious agent in the treatment of major depressive patients.

Adrenergic Uptake Inhibitors↗
PubMed2003

Quetiapine treatment of psychotic symptoms and aggressive behavior in patients with dementia with Lewy bodies: a case series.

The authors describe here the clinical outcomes of quetiapine treatment in nine patients with dementia with Lewy bodies (DLB) who manifested psychotic symptoms and aggressive behavior. Patients who had a score of 3 or higher on any of the three items of the Neuropsychiatric Inventory (NPI), agitation/aggression, hallucinations, and delusions, were given quetiapine 25-75 mg/day. Each patient's clinical status was assessed at baseline and after 4 and 8 weeks of treatment by using the NPI, Mini-Mental State Examination (MMSE), and Simpson-Angus Scale (S-A). Five of nine patients had a positive response with a decline of more than 50% in the sum of scores for three items of the NPI. The other three patients withdrew from quetiapine treatment due to somnolence or orthostatic hypotension. The remaining patient exhibited no clinically significant change in the NPI score. The S-A scale was not affected by quetiapine treatment in any patient. These findings suggest that quetiapine may be effective in treating psychotic symptoms and disruptive behavior in some patients with DLB. Further placebo-controlled, randomized, double-blind trials with this drug are needed to confirm this observation.

Aged↗
PubMed2003

Effects of the CYP 2D6 genotype and cigarette smoking on the steady-state plasma concentrations of fluvoxamine and its major metabolite fluvoxamino acid in Japanese depressed patients.

The effects of the cytochrome P450 (CYP) 2D6 genotype and cigarette smoking on the steady-state plasma concentrations (C(ss)) of fluvoxamine (FLV) and its demethylated metabolite fluvoxamino acid (FLA) were studied in 49 Japanese depressed patients receiving FLV 200 mg/d. The C(ss) of FLV and FLA were measured by HPLC, and the wild-type allele (*1) and two mutated alleles causing absent (*5) or decreased (*10) CYP 2D6 activity were identified by PCR methods. The patients were divided into three genotype groups by the number of mutated alleles: 12 cases with no (*1/*1), 27 cases with one (*1/*5 and *1/*10), and 10 cases with two (*5/*10 and *10/*10) mutated alleles. The means +/- SD of the C(ss) of FLV and FLA and the FLA/FLV ratio of all patients were 169.1 +/- 147.5 ng/mL, 83.9 +/- 52.7 ng/mL, and 0.71 +/- 0.50, respectively. The C(ss) of FLV and FLA were not significantly different among the three genotype groups. However, the FLA/FLV ratio was significantly lower in the patients with one (P < 0.05) and two (P < 0.01) mutated alleles than in those with no mutated allele. There was no significant difference between nonsmokers (n = 34) and smokers (n = 15) in these values. In the stepwise multiple regression, the C(ss) of FLA (P < 0.05) and FLA/FLV ratio (P < 0.001) showed significant negative correlations with the number of mutated alleles, and the FLA/FLV ratio was significantly (P < 0.05) lower in women than in men. The present study suggests that the CYP 2D6 genotype and cigarette smoking have no major impact on the C(ss) of FLV and FLA, though CYP 2D6 is involved in the demethylation of FLV.

Adult↗