Biomedical subjects

Yasuo Koike

Publications and source records attributed to Yasuo Koike.

11 recordsLinked to original sources

PubMed2007

Daytime polysomnography for early diagnosis and treatment of patients with suspected sleep-disordered breathing.

Excessive daytime sleepiness (EDS) is a common complaint among patients with sleep-disordered breathing (SDB). Population-based studies on traffic and industrial accidents suggest a relationship between EDS and life-threatening events, and adults with EDS have cognitive and memory problems. Nocturnal polysomnography (nPSG) is essential for diagnosing SDB but it is time and energy consuming. We examined the usefulness of daytime polysomnography (dPSG) for the early diagnosis and treatment of patients with suspected SDB. We studied 108 consecutive patients aged 51.9 +/- 13.5 years (mean+/-SD). All patients underwent dPSG and nPSG. The number of apnea/hypopnea episodes per hour (apnea/hypopnea index: AHI) and the number of 3% desaturation episodes per hour (desaturation index: DSI) were calculated. All patients were classified into two groups. The REM group consisted of subjects who had an AHI < or = 25/h, AHI(REM)/AHI(NREM) > 2, and AHI(NREM) < 15/h. Those who did not satisfy these criteria were placed in the NREM group. Continuous positive airway pressure (CPAP) titration was performed for patients whose AHI was > or =20/h on dPSG. Using the international classification of sleep disorders, 96 patients were diagnosed as obstructive sleep apnea [including five upper airway resistance syndrome (UARS) patients], six patients were snoring, four had idiopathic hypersomnia due to a medical condition, and two had circadian rhythm sleep disorders. The sensitivity of dPSG for AHI was 81.0%, specificity was 100%, and accuracy was 83.5%. The sensitivity and accuracy of dPSG for AHI in the REM group were considerably lower than in the NREM group. There was no significant difference for optimal CPAP between dPSG and nPSG. In the five patients with UARS, their AHI, DSI, and arousal index on dPSG were 0.92 +/- 1.2/h, 2.9 +/- 3.4/h, and 29.3 +/- 3.5/h, respectively, and their AHI and DSI on nPSG were 3.2 +/- 2.5/h and 2.8 +/- 2.4/h, respectively. However, their respiratory effort-related arousals were 37.9 +/- 7.4/h, and their arousal index was 33.2 +/- 6.3/h. The five patients with UARS were also treated with CPAP, and their daytime sleepiness was improved. Although dPSG has limitations, these results indicate that dPSG recording is clinically useful for the diagnosis of and determination of types of treatment in patients with suspected SDB.

Adult↗

PubMed2006

Factors contributing to sleep disturbance and hypnotic drug use in hemodialysis patients.

OBJECTIVE: Sleep disturbance and the use of hypnotic medications are common in patients on hemodialysis. Factors that contribute to sleep disturbance and the use of hypnotic medications in hemodialysis patients were investigated. METHODS: With the use of a questionnaire-based survey, we examined the prevalence of symptoms that reflect sleep disorders such as insomnia, restless legs syndrome (RLS), and snoring and use of hypnotic medications in 252 hemodialysis patients. RESULTS: The overall prevalence of insomnia was 59.1%, with the prevalence of difficulty in initiating sleep (DIS), difficulty in maintaining sleep (DMS), and early morning awakening (EMA) being 47.6, 24.2, and 28.2%, respectively. Daytime sleepiness and habitual snoring were reported by 42.5 and 33.7%, respectively. The prevalence of routine use of hypnotic drugs was 25.8%. Both RLS and age were significantly associated with insomnia [odds ratio (OR), 3.75; p 0.001, OR, 1.03; p < 0.01]. RLS was a significant factor for DIS, DMS, and EMA (OR, 2.26; p < 0.05, OR, 3.44; p < 0.0005, OR, 4.25; p < 0.0005) and age was a significant factor for DMS and EMA (OR, 1.03; p = 0.053, OR, 1.05; p < 0.005). Both insomnia and snoring were associated with the use of hypnotic drugs (OR, 2.97; p < 0.001, 1.59; p=0.13). CONCLUSION: Both RLS and sleep-disordered breathing may contribute to sleep disturbance in hemodialysis patients. RLS in particular may be an important factor in insomnia, which in turn is likely responsible for the high prevalence of hypnotic drug use in hemodialysis patients.

Adult↗

PubMed2006

Altered venous capacitance as a cause of postprandial hypotension in multiple system atrophy.

Patients with multiple system atrophy (MSA) often have clinically significant postprandial hypotension (PPH). To elucidate the cause of insufficient cardiac preload augmentation that underlies PPH, we recorded calf venous capacitance (CVC) by strain-gauge plethysmography, in 17 MSA patients and eight healthy controls before and after oral glucose ingestion. Among 17 MSA patients, nine who showed a decrease in systolic blood pressure exceeding 20 mmHg and were diagnosed with PPH. MSA patients without PPH showed a significant decrease in CVC and a significant increase in cardiac output after oral glucose ingestion, as did controls; those with MSA exhibiting PPH showed a significant increase in CVC and no significant change in cardiac output. The change in CVC correlated positively with the decrease in systolic and diastolic blood pressure after glucose ingestion, and also correlated negatively with the increase in cardiac output. Physiologically, PPH is prevented by a decrease in venous capacitance, which increases circulating blood volume and cardiac output. In some MSA patients, failure of venous capacitance to decrease may induce PPH.

Aged↗

PubMed2006

Sex differences in the relationships between electrocardiographic abnormalities and the extent of left ventricular hypertrophy by echocardiography.

BACKGROUND: Several criteria have been proposed for the electrocardiographic diagnosis of left ventricular hypertrophy (LVH). However, their diagnostic accuracy is questionable. Furthermore, the diagnostic accuracy of abnormalities in ST-T patterns for LVH is known to be uncertain, especially in women. We examined the relationship between electrocardiographic abnormalities and the extent of LVH. METHODS: We studied 76 men and 48 women who satisfied electrocardiographic voltage criteria for LVH (RV(5) or RV(6)> or = 2.6 mV, SV(1) + RV(5) or SV(1) + RV(6)> or = 3.5 mV). They were classified into three groups based on ST-T pattern: normal, early strain, and strain. We defined echocardiographic evidence of LVH as an LV wall thickness > or = 12 mm. RESULTS: LVH was identified by echocardiography in 55.3% of men and in 47.9% of women. In strain and early strain groups, the prevalence of echocardiographic LVH was significantly higher in men than in women (strain group: 100 vs 75%, P < 0.05, early strain group: 81.8 vs 42.1%, P < 0.05), it did not differ significantly between men and women in normal group. In men, QRS voltage values were significantly correlated with echocardiographic indices. In group strain of men, significant good correlations were observed between QRS voltage values and echocardiographic indices. However, in women, there were no significant correlation between QRS voltage values and echocardiographic indices even in strain group. CONCLUSIONS: The combined criteria of both QRS voltage and ST-T classification could provide a greater accuracy in diagnosing LVH compared to the criteria using QRS voltage alone in men rather than in women.

Echocardiography↗

PubMed2006

Differential myolysis of myocardium and skeletal muscle in hamsters with dilated cardiomyopathy: beneficial protective effect of diltiazem.

BACKGROUND: Although dilated cardiomyopathic hamsters (TO-2) with mutation of the delta-sarcoglycan gene exhibit histological features of muscular dystrophy, it remains to be elucidated whether both myocardium and skeletal muscle are injured in a similar manner. METHODS AND RESULTS: The progression of myolysis in both myocardium and skeletal muscle were assessed biochemically and pathologically in TO-2 and F1B control hamsters. Left ventricular (LV) function was assessed by echocardiography and cardiac catheterization. Both the plasma concentration of cardiac troponin T and the plasma activity of alpha-hydroxybutyrate dehydrogenase (HBD) peaked at 8 weeks of age, and thereafter reduced greatly in TO-2 hamsters. Activity of creatine kinase (CK) in TO-2 hamsters was significantly greater than in controls throughout the observation period. Pathological findings of both nuclear chain and central nuclei in skeletal muscles were observed in TO-2 hamsters throughout the observation period, suggesting regeneration. LV dysfunction was first evident at 8 weeks of age and deteriorated thereafter in TO-2 hamsters. Treatment of TO-2 hamsters with diltiazem from 5 to 8 weeks of age could avert the LV functional deterioration and the increment in alpha-HBD activity, but CK activity was unchanged. CONCLUSIONS: Despite myolysis in skeletal muscle occurring consistently throughout the observation period, cardiac myolysis occurred predominantly in the early phase. These initial cardiac events might involve coronary spasm and/or calcium overload in the myocardium.

Animals↗

PubMed2005

Influence of nasal resistance on initial acceptance of continuous positive airway pressure in treatment for obstructive sleep apnea syndrome.

BACKGROUND: Continuous positive airway pressure (CPAP) is considered as the standard therapy for obstructive sleep apnea syndrome (OSAS), but some patients with OSAS are unable to accept CPAP due to nasal obstruction and poor nasal airflow. OBJECTIVES: We assessed the influence of nasal resistance before beginning CPAP treatment on the initial acceptance of CPAP in OSAS patients. METHODS: The study subjects comprised 77 patients (74 males, 3 females) with primary OSAS, all of whom received CPAP treatment with nasal masks. Before trials, all subjects underwent overnight polysomnography, and nasal resistance was measured with active anterior rhinomanometry in the seated position on the first day of CPAP trial. RESULTS: The CPAP treatment was accepted by 56 patients after the initial trials with overnight polysomnography. Body mass index, the number of apnea/hypopnea episodes per hour (apnea/hypopnea index; AHI), and the number of episodes per hour with an oxygen desaturation of >3% (oxygen desaturation index) were significantly higher (p<0.01) and nasal resistance was lower (p=0.003) in patients who accepted CPAP than in those who did not. Logistic regression analysis, with patient age, body mass index, Epworth sleepiness scale score, AHI, oxygen desaturation index, and nasal resistance before CPAP treatment as explanatory variables, showed that nasal resistance (OR+0.1 Pa/cm3/s: 1.48; p=0.002) and AHI (OR+1 event/h: 0.93; p=0.003) were significant factors for CPAP non-acceptance. CONCLUSIONS: Nasal resistance before the beginning of CPAP treatment has a significant effect on the acceptance of CPAP in OSAS patients, and hence, could be a predictive parameter for the initial acceptance of CPAP.

Adult↗

PubMed2005

Assessment of continuous positive airway pressure treatment in obstructive sleep apnea syndrome using 24-hour urinary catecholamines.

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is related to diurnal sympathetic hyperactivity and increased blood pressure, both factors that are likely to lead to the development of cardiovascular disease. HYPOTHESIS: The study investigated whether 24-h urinary catecholamines would reflect the effect of obstructive sleep apnea on autonomic activity. METHODS: Standard polysomnography was performed in 17 patients with OSAS (age 53.7 +/- 13.5 years, mean +/- standard deviation). The number of apnea/hypopnea episodes per hour of sleep (apnea/hypopnea index [AHI]); number of oxygen desaturation episodes per hour (desaturation index [DSI]); arousals per hour (arousal index); lowest oxygen saturation (lowest SpO2); and percentages of stages 1, 2, 3/4, and rapid eye movement sleep (% stage 1, -2, and -3/4, and % REM, respectively) were measured. Overnight continuous positive airway pressure (CPAP) titration was performed the night after the baseline sleep measurements had been taken. Twenty-four-hour urinary adrenaline and noradrenaline were also examined. RESULTS: During the CPAP treatment, both 24-h urinary adrenaline and noradrenaline were significantly lower compared with natural sleep. Continuous positive airway pressure significantly decreased the AHI, DSI, % stage 1, and arousal index and significantly increased the lowest SpO2. There were no significant differences in % stage 2, % stage 3/4, and % REM between before and during CPAP treatment. Multiple analysis of covariance tests revealed that lowest SpO2 was the most important factor for increasing 24-h urinary noradrenaline levels (F = 4.75, p = 0.048). CONCLUSIONS: One night CPAP treatment could improve autonomic dysfunction. The assessment of 24-h urinary noradrenaline would provide important information for evaluating the effect of CPAP treatment.

Adult↗

PubMed2004

REM sleep is impaired by a small amount of alcohol in young women sensitive to alcohol.

OBJECTIVE: The effect of a small amount of alcohol on the sleep structure in relation to alcohol sensitivity was examined using polysomnography (PSG). METHODS: Alcohol sensitivity was evaluated using alcohol patch test for all subjects. PSGs were performed on three nights after one night for acclimation, and subjects consumed no alcohol, 0.28 or 0.69 g ethanol/kg body weight, respectively, before going to bed. The percentages of sleep time in each sleep stage of 1, 2, 3+4 and rapid eye movement (REM), REM latency, and REM cycle were calculated. SUBJECTS: Thirteen healthy female students (age 21.1 +/- 0.7 years) were enrolled in this study. RESULTS: In all subjects, there were no significant differences in any of the sleep parameters between baseline night and alcohol nights. Six of the 13 subjects were sensitive to alcohol, in whom %stage REM was significantly decreased by alcohol consumption (baseline night: 18.3 +/- 6.2%, alcohol night I: 9.8 +/- 5.1% and alcohol night II: 11.0 +/- 2.8%), and the REM latency was significantly prolonged. The standard deviation of REM cycle was significantly greater on alcohol nights I and II than baseline night. There were no significant differences in other sleep parameters. In the other seven subjects who were insensitive to alcohol, none of the sleep parameters were significantly affected by alcohol consumption. CONCLUSION: REM sleep was adversely affected by a small amount of alcohol in alcohol-sensitive healthy young women. Alcohol sensitivity might play some important role in impaired REM sleep by an ingestion of a small amount of alcohol.

Alcohol Drinking↗

PubMed2003

Skin sympathetic nerve function during sleep--a study with effector responses.

We investigated the effector-organ activities corresponding to skin sympathetic nerve activity (SSNA) during sleep in eight healthy adult volunteers. The following parameters of SSNA were recorded during night sleep: the spontaneous skin vasoconstriction and skin blood flow volume, by laser Doppler flowmetry; sweating, by the ventilated capsule method; and the galvanic skin response (GSR). Fluctuations of sweating and GSR were mainly observed on the dorsal side of the hand during night sleep. The frequency of GSR and sweat rate on the dorsal side of the hand were significantly lower during REM sleep than during NREM sleep. The frequency of spontaneous skin vasoconstriction was higher and blood flow was lower during REM sleep than during NREM sleep. These results indicate that sweating and blood flow in the skin are differentially regulated depending on the sleep stage. Our results also suggest that the sleep-regulating system is closely linked to thermoregulation, which is controlled by the sympathetic nervous system.

Adult↗

PubMed2003

Progressive development of pulmonary hypertension leading to right ventricular hypertrophy assessed by echocardiography in rats.

The present study aimed to evaluate the development of pulmonary hypertension by serial echocardiography, including measurements of pulmonary artery (PA) flow velocities, and correlate echocardiographic indices with pathological findings in rats administered monocrotaline (MCT). MCT (60 mg/kg body weight) or physiologic saline was administered to a total of 9 male Wistar rats at the age of 4 weeks (MCT group: n = 4, control group: n = 5, respectively). Echocardiography was performed serially until the age of 8 weeks. The ratio of right ventricular (RV) outflow tract dimensions to aortic dimensions increased progressively in the MCT group and became significantly greater than that of the control group after the age of 6 weeks. Peak PA velocity (Peak V) in the MCT group was significantly less than that of the control group at the ages of 7 and 8 weeks. The ratio of acceleration time to ejection time (AT/ET) in PA flow waveforms declined progressively and was significantly less than that of the control group after the age of 6 weeks. The ratio of RV weight to body weight (RVW/BW) in the MCT group was significantly greater than that of the control group. Both AT/ET ratio and Peak V were significantly inversely correlated with RVW/BW ratio. Furthermore, these echocardiographic findings were also significantly inversely correlated with the mean cross-sectional RV myocyte area. In conclusion, the progressive development of pulmonary hypertension leading to RV hypertrophy can be evaluated appropriately by echocardiography including PA flow Doppler indices in rats.

Animals↗

PubMed2003

Validity and application of noninvasive measurement of blood pressure in hamsters.

The aim of this study was to examine both the validity and application of noninvasive measurement of blood pressure (BP) at the brachial artery in hamsters. There were significant correlations between noninvasive and invasive values for systolic BP (SBP), mean BP, and diastolic BP (r = 0.96, r = 0.93, r = 0.88, respectively, all p < 0.0001). Furthermore, SBP appeared to be the most accurate noninvasive BP index because both proportional and constant systematic errors were the least among the three indices. Peripheral vascular resistance calculated by combination with echocardiographic indices actually reflected the prominent alpha 1-adrenergic drive induced by beta-adrenergic blockers. In conclusion, noninvasive BP measurement at the brachial artery can provide useful information regarding the integrated cardiovascular function in hamsters.

Animals↗