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Biomedical subjects

M Uchiyama

Publications and source records attributed to M Uchiyama.

At least 145 records · Page 8Linked to original sources
PubMed1999

Poor recovery sleep after sleep deprivation in delayed sleep phase syndrome.

To clarify disturbances in sleep regulation in patients with delayed sleep phase syndrome (DSPS), we studied three patients with DSPS and seven healthy controls. Sleep propensity and melatonin rhythms after 24-h sleep deprivation were investigated under dim light condition by using the ultra-short sleep-wake schedule. The sleep propensity curves displayed clear differences between DSPS patients and the controls. During the subjective day when melatonin was not produced, recovery sleep after the sleep deprivation did not occur in DSPS patients, while recovery sleep occurred during the subjective day in controls. This suggests that DSPS may involve problems related to the homeostatic regulation of sleep after sleep deprivation.

Adult↗
PubMed1999

Diurnal fluctuation of sleep propensity across the menstrual cycle.

Most women experience sleep changes across the menstrual cycle. We applied the ultra-short sleep-wake schedule to healthy females to compare their 24-h sleep propensity rhythms in the follicular and luteal phases. The daytime (09.00-16.30 h) subjective sleepiness and the number of slow wave sleep-containing nap trials increased in the luteal phase compared to the follicular phase, but the mean sleep propensity did not change. During the periods of 17.00-00.30 h and 01.00-08.30 h there were no differences between the two phases. These results suggest that increased daytime sleepiness in the luteal phase may be related to brain mechanisms controlling slow wave sleep.

Adult↗
PubMed1999

Effects of a small dose of triazolam on P300.

Ten healthy men (mean age, 33.9 years) participated in two experimental sessions cross-overed randomly in a double-blind manner: one with the placebo and another with 0.125 mg of triazolam (TRZ). Resting electroencephalography and event-related potential under oddball paradigm were recorded before the drug administration, and 1, 2, 4, 6 and 8 h after that. P300 waveforms were analyzed by peak amplitudes and 30-ms bin data. Triazolam may cause cognitive dysfunction without general sedation or apparent sleepiness, and this effect appeared 2 h, 4 h and 6 h, most prominently 6 h, after TRZ administration.

Adult↗
PubMed1999

Correlation between the circadian sleep propensity rhythm and hormonal rhythms under ultra-short sleep-wake cycle.

The aim of this study was to clarify effects of hormonal and temperature rhythms on circadian fluctuations of sleep propensity. Ten healthy females underwent 24-h sleep deprivation and entered the circadian sleep propensity assessment setting under the ultra-short sleep-wake schedule. During the experiment, sleep propensity rhythm, rectal temperature, and 24-h serum hormone profiles (melatonin, cortisol and thyroid-stimulating hormone) were investigated. The circadian sleep propensity rhythms had two apparent peaks (afternoon and nocturnal peaks) and a trough (nocturnal sleep gate). The timings of the nocturnal sleep gate and the nocturnal peak were correlated exclusively with temperature and melatonin rhythms (P < 0.05), while that of the afternoon peak was significantly correlated with habitual wake time and melatonin rhythm. These results indicate that the circadian sleep propensity rhythm is influenced not only by the circadian pacemaker, but also by sleep habit.

Adult↗
PubMed1999

Lifestyles and sleep disorders among the Japanese adult population.

To clarify the effects of daily stress, habitual exercise, drinking and smoking on the prevalence of sleep disorders, we selected 4000 residents (> or =20 years) in Japan by stratified random sampling and carried out structured interviews (response rate 75.8%). Frequencies of sleep disorders (difficulty initiating sleep: DIS; difficulty maintaining sleep: DMS; early morning awakening and hypnotic medication use) were treated as dependent variables. Significant effects of stress were prevalent in all sleep disorders. Habitual exercise had significant negative association with DIS and DMS. Drinking and smoking did not affect sleep disorders.

Adult↗
PubMed1999

Serum lipoproteins and apolipoprotein E in infants with congenital hypothyroidism.

BACKGROUND: Hypothyroid adults have a high risk of atherosclerosis, secondary to increased levels of various cholesterol fractions, particularly low-density lipoprotein cholesterol (LDL-C). We investigated the existence of a correlation between thyroid hormone deficiency and serum lipoproteins and a possible effect of different apolipoprotein E (apoE) phenotypes on lipoprotein levels in 75 infants with hypothyroidism. METHODS: Seventy-three of the 75 infants had congenital hypothyroidism. At the age of one month, prior to the initiation of thyroid hormone substitution therapy, thyroid-stimulating hormone (TSH), thyroid hormones and lipid profile parameters were determined. Subsequently, apoE phenotyping in all patients was performed by isoelectric focusing followed by immunoblotting. RESULTS: Significant negative correlations were identified between triiodothyronine (T3) and LDL-C and total cholesterol (TC) levels and between thyroxine (T4) and TC levels. There were no correlations between TSH and free (F)T4 and lipid profile parameters. Although infants carrying at least one E4 allele had higher LDL-C (as well as TC and triglyceride) levels than those carrying at least one E2 allele, these differences were not statistically significant. No significant differences in thyroid hormones were noted in E4 allele carriers in comparison with other patients. CONCLUSIONS: The observed lack of a significant correlation between thyroid hormones (except T3), apoE phenotypes and lipoprotein levels suggests that, early in infancy, other factors may play a more important role in determining lipoprotein levels.

Adult↗
PubMed1999

Thyroxine inversely regulates serum intermediate density lipoprotein levels in children with congenital hypothyroidism.

BACKGROUND: Although there have been numerous studies on the effects of thyroid hormones on serum lipid profiles, the effects of thyroxine on intermediate how density lipoprotein (IDL) remain uncertain. In an attempt to clarify, this issue, under conditions with very little influence exerted by sex hormones on serum lipid profiles, we studied the relationship between serum thyroid hormone levels and the proportion of serum IDL fractions in children. METHODS: Nineteen children with congenital hypothyroidism and 13 children with non-thyroid diseases were enrolled in this study. Blood samples were taken to measure serum thyroid stimulating hormone, triiodothyronine, free thyroxine (FT4), total cholesterol, high density lipoprotein (HDL) cholesterol, triglyceride and apolipoprotein levels. Lipoprotein fractions, including very low density lipoprotein (VLDL), IDL, low density lipoprotein (LDL) and HDL, were determined by their electrophoretic mobility in a non-denaturing polyacrylamide gel. RESULTS: The proportion of IDL fractions showed a significant inverse correlation with serum FT4 levels and a significant correlation with serum total cholesterol and apolipoprotein B and C-II levels. Serum VLDL, LDL and HDL fractions did not correlate with serum thyroid hormone levels. CONCLUSION: From these results and other studies, we suggest that thyroxine promotes the conversion of IDL into LDL, possibly by its stimulatory effects on hepatic lipase activity.

Apolipoproteins↗
PubMed1999

A study of therapy for pediatric hepatoblastoma: prevention and treatment of pulmonary metastasis.

Our results of treatment for pediatric hepatoblastoma are presented with special emphasis on pulmonary metastasis. The pulmonary metastasis rate of hepatoblastoma was 44% (11/25). In 19 patients with resected hepatoblastomas, the 5-year survival rate without pulmonary metastasis was 90% (9/10); while with pulmonary metastasis it was 22% (2/9). Six patients with unresected hepatoblastomas all died within 4 months regardless of chemotherapy and/or metastasis. To improve survival in patients with hepatoblastoma, preoperative or postoperative chemotherapy was thought to be essential for tumors extending over 2 hepatic segments and having predictable factors for pulmonary metastasis (large size or histological evidence of capsular invasion). A long-term multidisciplinary approach including hepatic lobectomy, current multiagent chemotherapy (including CDDP, THP-ADR), and partial pulmonary resection for localized lung areas with metastases would ultimately be needed.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Sacrococcygeal teratoma: a series of 19 cases with long-term follow-up.

A series of 19 cases of sacrococcygeal teratoma (SCT) with follow-up of 5 to 25 years is presented. Twelve patients were neonates, age 0 to 26 days (5 immature teratomas and 7 mature teratomas, representing 3, 6, 2, and 1 Altman's type I, II, III, and IV tumors, respectively), four were infants, age 1 to 6 months (all mature teratomas, representing 1, 1, and 2 Altman's type I, II, and IV tumors), and 3 were children, age 1 to 4 years (all malignant teratomas, all Altman's IV tumors). Eight babies were delivered by elective caesarean section (CS). Though the mean gestational age at CS was 34.3 weeks in our series, we now believe that CS often must be performed earlier, depending on a tumor size or fetal condition. Eleven neonates and 4 infants were operated upon using a sacral approach in 10 and an abdominosacral approach in 5, and all survived. However, 4 patients had neurogenic bladder and were treated by urinary catheterization or vesicostomy for 2 to 5 years after surgery. Postoperative urogenital sequelae are seen in patients with a large tumor, urethral compression, urinary retention, or edema of the lower body. Malignant tumors usually had metastasized by the time of diagnosis, but the prognosis for outcome has been improved following surgery and combination chemotherapy.

Adolescent↗
PubMed1999

Circadian variation of plasma arginine vasopressin concentration, or arginine vasopressin in enuresis.

The objective of these studies was to determine a relationship between primary nocturnal enuresis and arginine vasopressin (AVP) secretion. The first study compared 24-h AVP secretion profiles of enuretic (n = 9) and non-enuretic children (n = 8). Blood samples were collected at 1-h intervals for 24 h. In the second study, nocturnal AVP secretion in group A (n = 40)--with low urinary osmotic pressure (UOP) and large nocturnal urine output (NUO)--was compared with that in group D (n = 11) with normal UOP and small NUO. Plasma AVP levels were measured at 30-min intervals, immediately after falling asleep until 06.00 the following morning. The results of the first study showed that the plasma AVP level was significantly lower (p < 0.05-0.001) in the enuretic group between 23.00 and 04.00. The second study showed that group A had significantly lower AVP levels (p < 0.05-0.001) than group D throughout the night. The mean AVP level during night sleep was 0.64 +/- 0.23 pg/ml in group A and 1.43 +/- 0.66 pg/ml in group D. The results of the first study suggest that decreased nocturnal AVP secretion is a cause of bedwetting. However, the results of the second study suggest that nocturnal enuresis cannot be explained by a decrease in nocturnal AVP secretion alone.

Adolescent↗
PubMed1999

Low-dose succinylcholine facilitates laryngeal mask airway insertion during thiopental anaesthesia.

We have assessed the optimal dose of succinylcholine to provide satisfactory conditions for insertion of a laryngeal mask airway (LMA) without causing myalgia during induction of anaesthesia with thiopental. We studied 60 adult patients, allocated randomly to one of three groups: group 1 (n = 20) received normal saline, group 2 (n = 20) received succinylcholine 0.25 mg kg-1 and group 3 (n = 20) received succinylcholine 0.5 mg kg-1. Insertion of the LMA was performed 1 min after administration of succinylcholine or saline. Insertion conditions were significantly better in group 3 compared with groups 1 and 2. The incidence of adverse responses on insertion was significantly higher in groups 1 and 2 than in group 3. Four of 20 patients (20%) in group 3 complained of myalgia, which was higher than that in group 1 (0%) and group 2 (10%), but there were no significant differences between groups on the day of operation. On day 3 after operation, seven patients (35%) in group 3 complained of myalgia, which was significantly higher than that in group 1 (5%) and group 2 (20%). Time from administration of succinylcholine to resumption of spontaneous respiration was significantly longer in groups 2 (194.9 (SD 50.4) s) and 3 (234.2 (34.3) s) than in group 1 (84.7 (32.4) s). There was also a significant difference between groups 3 and 2 for duration of apnoea.

Adult↗
PubMed1999

Effects of xenon on the performance of various respiratory flowmeters.

BACKGROUND: The anesthetic gas xenon has distinctly different physical properties compared with air, nitrous oxide, or oxygen. This led us to predict that xenon would affect the performance of commercially available flowmeters. METHODS: Flow was generated by an anesthesia ventilator connected to a lung simulator via a semiclosed breathing circuit. With the system filled with air or with various concentrations of xenon or nitrous oxide in a balance of oxygen, the tidal volume was measured with two rotating vanes, a Pitot tube, a variable-orifice flowmeter, and two constant-temperature hot-wire flowmeters. RESULTS: Although xenon minimally affected both rotating vane flowmeters, it caused the Pitot tube and the variable-orifice flowmeters to overread in proportion to the square root of the density of the gas mixture used (xenon is 4.6 times more dense than air). In contrast, the hot-wire anemometers underread with xenon; for example, their readings in the presence of 45% and 70% xenon were less than 10% of those displayed when air was used. Nitrous oxide minimally affected all the flowmeters except the variable-orifice device. The Pitot flowmeter was also affected, but only when its gas analyzer port was open to the ambient air so that it no longer corrected its readings for changes in gas composition. In these cases, nitrous oxide produced overreadings in the same manner as did xenon. CONCLUSION: Among the four types of flowmeters studied, only the rotating-vane type is sufficiently accurate for use during anesthesia with xenon.

Anesthetics, Inhalation↗
PubMed1999

Melatonin rhythms in delayed sleep phase syndrome.

The aim of this study was to compare circadian and sleep characteristics between patients with delayed sleep phase syndrome (DSPS) and healthy controls. The authors studied 8 DSPS patients and 15 normal controls. Serum melatonin concentration was assessed every hour for 24 h under dim light conditions. The sleep phase and the melatonin rhythm in DSPS patients were significantly delayed compared to those in normal controls. Sleep length was significantly greater in DSPS patients compared to that in controls, but the duration of melatonin secretion did not differ between the two groups. The final awakening, relative to melatonin onset, melatonin midpoint, and melatonin offset, was significantly longer in DSPS patients than in controls. By contrast, the timing of sleep onset relative to melatonin rhythm did not differ between the two groups. The authors found a significant positive correlation between sleep phase markers and melatonin phase markers in DSPS. They postulate that a delayed circadian pacemaker may be responsible for delayed sleep phase syndrome. The alteration of phase angle between melatonin rhythm and sleep phase suggested that not only the delay of the circadian clock but also a functional disturbance of the sleep-wake mechanism underlies DSPS.

Adolescent↗
PubMed1999

Neurogenic vasodilatation of canine isolated small labial arteries.

Mechanisms underlying vasodilatation to nerve stimulation by electrical pulses and nicotine were analyzed in isolated canine small labial arteries. Transmural electrical stimulation (5 and 20 Hz) produced a contraction followed by a relaxation in labial arterial strips denuded of the endothelium, partially contracted with prostaglandin F2alpha. The contraction was abolished by prazosin or combined treatment with alpha, beta-methylene ATP. In the treated strips, neurogenic relaxation was abolished by NG-nitro-L-arginine (L-NA), a nitric oxide (NO) synthase inhibitor, and restored by L-arginine. The D-enantiomers were without effect. Nicotine (10(-4) M) also relaxed the arteries, in which the contractile response was abolished by prazosin and alpha, beta-methylene ATP. The relaxant response was attenuated but not abolished by L-NA; the inhibition was reversed by L-arginine. The remaining relaxation by nicotine was abolished by calcitonin gene-related peptide (CGRP)-[8 to 37], a CGRP1 receptor antagonist. Relaxations elicited by a lower concentration of nicotine (2 x 10(-5) M) sufficient to produce similar magnitudes of response to those induced by 5-Hz electrical nerve stimulation were also inhibited partially by L-NA. Histochemical study with the NADPH-diaphorase method demonstrated positively stained nerve fibers and bundles in the arterial wall, suggesting the presence of neuronal NO synthase. It is concluded that the relaxation induced by electrical nerve stimulation of small labial arteries is mediated exclusively by NO synthesized from L-arginine in nerve terminals, whereas nicotine in the concentrations used evokes relaxations by a mediation of nerve-derived NO and also CGRP, possibly from sensory nerves. The reason why nicotine but not electrical pulses stimulates sensory nerves and elicits vasorelaxation remains unsolved.

Animals↗
PubMed1999

[Diagnostic value of urinary N-telopeptide of type I collagen in prostate cancer: comparison with bone scintigraphy].

The usefulness of a new biochemical marker of bone resorption, N-telopeptide of type I collagen (NTx), in the diagnosis of bone metastasis was assessed in 69 prostate cancer patients. Based on the bone scintigraphy findings, the patients were divided into a bone metastasis (+) group (n = 36) and a bone metastasis (-) group (n = 33). The urinary NTx level was significantly higher in the bone metastasis (+) group than in the bone metastasis (-) group (95.5 +/- 18.5 nM BCE/mM Cr vs. 63.3 +/- 7.9 nM BCE/mM Cr). There was a tendency for greater variability in urinary NTx levels during a 2 month-period in the bone metastasis (+) group than in the bone metastasis (-) group. The urinary NTx level of the 6 patients who were clinically staged as (4+) according to the extent of disease (EOD) grading system was 211.4 +/- 96.9 nM BCE/mM Cr, and was significantly higher (p < 0.05) than in the (-) group. However, there was not a significant difference in urinary NTx levels between the (1+) to (3+) groups and the (-) group. In conclusion, measuring urinary NTx levels in useful in diagnosing bone metastasis in view of the fact that it is a simple and noninvasive procedure. While it is not as sensitive as bone scintigraphy, it may be used to supplement bone scintigraphy.

Adenocarcinoma↗