Biomedical subjects

A Ikeda

Publications and source records attributed to A Ikeda.

At least 109 records · Page 6Linked to original sources

PubMed2000

Coagulofibrinolytic assessment of effects of bezafibrate on hypertriglyceridemia in postmenopausal women.

The present study investigates the effect of bezafibrate on lipid levels and coagulofibrinolytic factors. Subjects enrolled in the study included 124 postmenopausal women with hypertriglyceridemia. We examined the levels of tissue plasminogen activator (t-PA), plasminogen activator inhibitor type-1 (PAI-1), and blood coagulation factors VII and X as parameters of coagulofibrinolysis. After 12 weeks of bezafibrate therapy, mean serum triglyceride (TG) and remnant-like particle lipoprotein cholesterol (RLP-C) levels significantly decreased from baseline. Activated factor X levels decreased significantly by 11.3% (P < 0.01) and the ratio of tPA/PAI-1 (0.146+/-0.07) increased significantly by 37.7% from baseline (P < 0.05). The rates of change in activated factor VII and PAI-1 showed a significant positive correlate with the rates of change in TG and RLP-C (P = 0.001). These present findings suggest that bezafibrate improves triglyceride-rich lipoprotein metabolism and coagulofibrinolytic activity by increasing fibrinolysis in postmenopausal women with hypertriglyceridemia.

Bezafibrate↗

PubMed2000

Nonlinear Markov process amplitude EEG model for nonlinear coupling interaction of spontaneous EEG.

To develop an appropriate model for representing spontaneous electroencephalography (EEG) is an important and necessary work in the field of neuroscience. The Markov process amplitude (MPA) EEG model has been proposed in our previous work for representing the features of the EEG in terms of a few parameters. However, being a linear model, the linear MPA EEG model cannot perfectly describe the spontaneous EEG that displays nonlinear phenomena. In this paper, the nonlinear Markov process amplitude (nonlinear MPA) EEG model that includes nonlinear components is introduced. The consistent consideration of the nonlinear features of the EEG investigated by N. Wiener and P. L. Nunez can be seen from the nonlinear MPA EEG model. The similarity in the time domain and the goodness of fitting in the frequency domain with respect to the ongoing EEG are shown. As a result, the EEG power spectrum can be decomposed into the spontaneous components and the nonlinearly coupled components by use of the nonlinear MPA EEG model, which is useful for a better understanding the mechanism of the EEG generation.

Biomedical Engineering↗

PubMed2000

Use of cavernous sinus EEG in the detection of seizure onset and spread in mesial temporal lobe epilepsy.

PURPOSE: The study goal was to evaluate the clinical usefulness of intravenous EEG recording by placing wire electrodes in the cavernous sinus (CS) and the superior petrosal sinus (SPS) in patients with intractable temporal lobe epilepsy (TLE), with special emphasis on the ictal recording. METHODS: We placed Seeker Lite-10 guide wire as electrodes in the bilateral CS, SPS, or both to simultaneously record both ictal and interictal EEGs with the scalp EEG in five patients with TLE. In addition, in one patient, we averaged interictal scalp and intravascular EEG time-locked to the epileptiform discharge recorded from the CS/SPS-EEG to further delineate the relationship of the spikes between scalp and intravenous recording. RESULTS: In four of five patients, clinically useful recording was obtained to determine ictal focus. We recorded habitual seizures in three patients, and the detailed characteristics of ictal epileptiform discharges were shown. The averaged waveform of interictal epileptiform discharges clarified the spike distribution in the scalp EEGs, which was otherwise undetectable in the single trace. All of the patients completed the intravenous EEG monitoring without any neurological or psychological problems. CONCLUSIONS: The CS/SPS-EEG is a relatively noninvasive method that is useful for the detection of ictal focus and its spreading pattern and thus for the selection of surgical candidate among patients with intractable TLE. Although the number of seizures detected during the short monitoring period may be limited, due to the advantages of its safety and simplicity, it is worth trying for potential surgical candidates before more invasive examinations are applied. A further study with a larger number of patients is needed to estimate its practical risk.

Adult↗

PubMed2000

Chronic use of continuous dosing of long-term nitrates does not prevent cardiac events in patients with severe acute myocardial infarction.

This study was performed to investigate the effects of the chronic use of continuous, not eccentric, dosing of nitrates on cardiac events in patients with severe acute myocardial infarction. A total of 1,303 patients with healed myocardial infarction were divided into two groups: treatment with nitrates or nontreatment. Primary end points were nonfatal and fatal recurrent myocardial infarction, death from congestive heart failure and sudden death. Among the 725 patients treated with nitrates, 45 patients (6.2%) experienced cardiac events during the observation period, whereas only 17 of the 578 patients treated without nitrates (2.9%) had cardiac events. This difference was statistically significant (p < 0.01; odds ratio 2.18, 95% confidence interval 1.24-3.86). In Killip class II-IV patients, the incidence of cardiac events in patients with nitrates was significantly greater than in patients without nitrates (18.8 vs. 3.5%, p < 0.05). The chronic use of continuous, not eccentric, dosing of nitrates did not prevent cardiac events in patients with severe acute myocardial infarction.

Acute Disease↗

PubMed2000

Automatic detection of open and closed eye states in the electroencephalographic (EEG) record for background EEG interpretation by the trigger method.

Automatic detection of open and closed eye states in electroencephalographic (EEG) records was investigated in this study as a part of procedures for the precise interpretation of the background EEG to achieve a comprehensive automatic EEG interpretation system. The features of eye open and closure were extracted from the EEG using a Markov process amplitude (MPA) EEG model, which could efficiently express the features of the EEG using a small number of parameters. A new technique, named the trigger method, was also developed to overcome the difficulty resulting from large differences in the EEG features among different subjects, because an accurate detection could not be obtained by using the conventional threshold method. The proposed method gave satisfactory results which conformed with those of visual inspection by a qualified EEGer and could be clinically used as a preprocessing method for the automatic interpretation of the awake background EEG.

Adult↗

PubMed2000

The effects of oxitropium bromide on exercise performance in patients with stable chronic obstructive pulmonary disease. A comparison of three different exercise tests.

The purpose of the present study was to compare the characteristics of three different exercise tests in evaluating the effects of oxitropium bromide on exercise performance. Thirty-eight males with stable chronic obstructive pulmonary disease (COPD) (FEV(1) = 40.8 +/- 16.5% predicted; mean +/- SD) completed randomized, double-blind, placebo-controlled, crossover studies for each exercise test. The exercise tests were performed 60 min after the inhalation of either oxitropium bromide 400 microg or placebo. The patients performed 6-min walking tests (6MWT) on Days 1 and 2, progressive cycle ergometry (PCE) on Days 3 and 4, and cycle endurance tests at 80% of the maximal workload of PCE on Days 5 and 6. Spirometry was conducted before and at 45 and 90 min after the inhalation. Oxitropium bromide significantly increased FEV(1) as compared with placebo. Oxitropium bromide increased the endurance time significantly, by 19% (p < 0.001), and caused a small but significant increase in the 6-min walking distance by 1% (p < 0.05), but induced no significant increase in maximal oxygen consumption (V O(2)max) in PCE. The responses in these three exercise tests were different, and we conclude that the endurance test was the most sensitive in detecting the effects of inhaled anticholinergic agents on exercise performance in patients with stable COPD. An endurance procedure may be performed to detect clinical changes in evaluating the effects of oxitropium bromide on exercise performance.

Administration, Inhalation↗

PubMed2000

Percutaneous transluminal coronary angioplasty performed 24-48 hours after the onset of acute myocardial infarction improves chronic-phase left ventricular regional wall motion.

The authors investigated the capacity of percutaneous transluminal coronary angioplasty (PTCA) performed 24-48 hours after the onset of acute myocardial infarction (AMI) to improve regional left ventricular wall motion. Twenty-four patients were divided into two groups: a PTCA group who received successful PTCA (14 cases) and a non-PTCA group (10 cases) who did not receive PTCA. Left ventricular end-diastolic volume (LVEDV) increased significantly (p<0.01) from 57+/-14 mL/m2 during the acute phase to 83+/-16 mL/m2 during the chronic phase in the non-PTCA group, whereas no significant change in LVEDV was seen in the PTCA group (69+/-26 vs. 76+/-16 mL/m2). In addition, in patients with 99% stenosis/thrombolysis in myocardial infarction (TIMI) grade 3 flow, increases in regional left ventricular wall motion (delta(sd)/chord) at the infarcted site between the acute and chronic phases were significantly greater in the PTCA group than in the non-PTCA group (2.49+/-1.05 vs. 0.67+/-0.65, p<0.01). PTCA performed 24-48 hours after the onset of AMI improved wall motion at the infarcted site.

Aged↗

PubMed2000

Development of obesity in transgenic rats with low circulating growth hormone levels: involvement of leptin resistance.

BACKGROUND: Human growth hormone (hGH) transgenic (TG) rats have been produced in our laboratory. These TG rats are characterized by low circulating hGH levels, virtually no endogenous rGH secretion, and massive obesity. OBJECTIVE: To elucidate how energy balance and leptin sensitivity contributed to the establishment of this obesity. DESIGN AND METHODS: Food intake, locomotor activity and leptin concentrations in serum and cerebrospinal fluid were measured in TG rats and their non-transgenic littermates (control). The effect of intraperitoneal and intracerebroventricular injection of leptin on food intake and body weight gain was also examined. RESULTS: An increase in food intake and a decrease in locomotor activity were observed from 4 and 7 weeks of age, respectively, in the transgenic rats compared with control. Serum leptin concentrations of the transgenic rats were more than twice as high as those of control rats and were associated with an increased white adipose tissue mass and ob gene expression. Intraperitoneal injection of leptin significantly decreased food intake and body weight gain in control rats, but not in transgenic rats. Leptin concentration in the cerebrospinal fluid of transgenic rats was not different from that of control rats, and intracerebroventricular injection of leptin was similarly effective in reducing food intake and body weight gain as it was in control rats. CONCLUSIONS: These results suggest that the transgenic rats, whose GH secretion is suppressed, develop obesity due to early onset of an increase in food intake and a decrease in locomotor activity with leptin resistance resulting from deteriorating leptin transport from peripheral blood to cerebrospinal fluid.

Adipose Tissue↗

PubMed2000

[Drug treatment for secondary prevention of myocardial infarction].

The effects of drug treatment on cardiac events for 11 years from January 1986 to December 1996 were investigated in 1,483 patients with myocardial infarction, 1,164 men and 319 women (mean age 60.1 +/- 11.2 years), followed up for 17.4 +/- 20.9 months. Seventy-one patients (4.8%, 33 cases per 1,000 person-year) had cardiac events (recurrent myocardial infarction, sudden death and death by congestive heart failure). Multivariate analysis showed treatment with cholesterol lowering agents and beta-blockers reduced cardiac events, whereas administration of antiarrhythmic agents increased cardiac events. Univariate analysis showed that the incidence of cardiac events was 2.2% in patients treated with cholesterol lowering agents but 6.2% in patients without treatment, showing a significant difference (p < 0.01). The incidence was 3.2% for patients treated with beta-blockers and 6.8% for those without (p < 0.01), showing that beta-blockers were also effective to reduce cardiac events. Antiplatelet agents were also effective (3.7% vs 7.1%, p < 0.01). Calcium antagonists, angiotensin converting enzyme inhibitors and warfarin were not effective. Nitrates (6.0% vs 3.1%, p < 0.01) and antiarrhythmic agents (13.7% vs 3.6%, p < 0.01) increased the incidence of cardiac events. A placebo-controlled, double blind, large clinical multicenter study is required to confirm these results.

Adrenergic beta-Antagonists↗

PubMed2000

Clinical efficacy of clenbuterol and propiverine in menopausal women with urinary incontinence: improvement in quality of life.

The present study evaluated the effects of clenbuterol and propiverine therapy on postmenopausal urinary incontinence. The patients consisted of 89 postmeopausal women with stress or urge incontinence who had consulted our out-patient clinic between March 1994 and February 1999. Patients were treated with either clenbuterol for stress incontinence or propiverine for urge incontinence. The administration period for both drugs was eight weeks. The cure rates for clenbuterol and propiverine were 41.2% and 52.6%, respectively. Both treatments significantly decreased the frequencies of incontinence, 24-h. voiding and nocturnal voiding, and both resulted in an overall clinical improvement. Furthermore, the two treatments resulted in significant subjective improvements in quality of life. We conclude that both medical treatments resulted in an improvement in urinary incontinence and contributed to overall quality of life. The present study demonstrated the necessity of contributed urinary incontinence with improvement in quality of life of postmenopausal women.

Aged↗

PubMed1999

Immunosuppressant FK506 activates NF-kappaB through the proteasome-mediated degradation of IkappaBalpha. Requirement for Ikappabalpha n-terminal phosphorylation but not ubiquitination sites.

The immunosuppressant FK506 activates NF-kappaB through IkappaBalpha degradation in nonlymphoid cells. In the present study, we analyzed mechanisms by which FK506 induces IkappaBalpha degradation. We found that FK506 induces the degradation of both IkappaBalpha and IkappaBbeta and that the time courses of the FK506-induced degradation are quite different from degradation induced by interleukin 1 (IL-1). Despite this difference, FK506-induced IkappaBalpha degradation was dependent on the N-terminal Ser-32 and Ser-36 phosphorylation sites and was mediated by proteasomes, as is the case for IL-1-induced IkappaBalpha degradation. We further showed that FK506 induces weak and slow phosphorylation of IkappaBalpha at Ser-32. However, unlike IL-1-induced degradation, IKK-1 and IKK-2 were not activated significantly nor was FK506-induced IkappaBalpha degradation dependent on the N-terminal ubiquitination sites (Lys-21 and Lys-22). These results therefore indicate that FK506 and IL-1 utilize similar but distinct mechanisms to induce the phosphorylation and degradation of IkappaBalpha.

Amino Acid Sequence↗

PubMed1999

Prevalence, incidence, and awareness in the treatment of menopausal urinary incontinence.

OBJECTIVES: To investigate the prevalence of urinary incontinence and to evaluate the awareness of treatment in postmenopausal women. METHODS: The study group was comprised of 3026 postmenopausal women consulting the outpatient clinic. One component of the urological questions was formulated to determine the voiding habits and presence or absence of urinary incontinence. The incontinent responders were questioned further regarding the nature of the urine loss to determine the severity of incontinence. RESULTS: It was reported by 26.3% (795/3026) of the respondents that they currently had urinary incontinence. They were classified by types as follows: stress 64.9%, urge 18.6%, and mixed incontinence 7.3%. The incidence of women who desired medical treatment for incontinence was only 2.9% (87/3026), while the incidence of women who actually received medical treatment for urinary incontinence was 1.9% (56/3026). CONCLUSIONS: We conclude that urinary incontinence was prevalent to a significant extent among postmenopausal women, but that few affected individuals in this group consulted the medical center desiring clinical treatment. The present study demonstrated that it is necessary to improve the awareness of postmenopausal women concerning the benefits of seeking treatment for urinary incontinence, in order to improve their quality of life.

Adult↗

PubMed1999

Pre-movement gating of short-latency somatosensory evoked potentials.

Somatosensory evoked potentials (SEPs) are reduced in amplitude during movement (gating). The mechanism involves central gating of afferent input and competition from other afferents activated by the movement. We distinguished these two by giving 11 normal subjects a warning sound followed 1 s later by an electric stimulus to the right median nerve at the wrist. The latter served both as a cue to start a finger movement and as stimulation to evoke SEPs. Gating effects were widespread in frontal (N30) and central (N60) areas, but were also seen, albeit to a lesser extent, in the recordings at P3 (P30). Since finger movement began after the stimulus, such gating must have been purely central in origin, presumably reflecting motor preparation.

Adult↗

PubMed1999

Somesthetic function of supplementary motor area during voluntary movements.

To clarify the somesthetic functions of the supplementary motor area (SMA), we recorded the cortical potentials following the median nerve electric stimulation directly from the SMA and investigated the modulation caused by voluntary movements in two patients with intractable SMA seizures. The evoked potentials over the SMA consisted of positive (61.5ms) and negative (100.0 ms) peaks, which were enlarged by voluntary movements of the stimulated hand. The present finding is in strong contrast with the attenuation (gating) of the response at the primary sensorimotor area (SM1) and suggests that the voluntary movements differently modulate the somatosensory functions of SMA and SM1.

Adult↗

PubMed1999

Activities of the primary and supplementary motor areas increase in preparation and execution of voluntary muscle relaxation: an event-related fMRI study.

Brain activity associated with voluntary muscle relaxation was examined by applying event-related functional magnetic resonance imaging (fMRI) technique, which enables us to observe change of fMRI signals associated with a single motor trial. The subject voluntarily relaxed or contracted the right upper limb muscles. Each motor mode had two conditions; one required joint movement, and the other did not. Five axial images covering the primary motor area (M1) and supplementary motor area (SMA) were obtained once every second, using an echoplanar 1.5 tesla MRI scanner. One session consisted of 60 dynamic scans (i.e., 60 sec). The subject performed a single motor trial (i.e., relaxation or contraction) during one session in his own time. Ten sessions were done for each task. During fMRI scanning, electromyogram (EMG) was monitored from the right forearm muscles to identify the motor onset. We calculated the correlation between the obtained fMRI signal and the expected hemodynamic response. The muscle relaxation showed transient signal increase time-locked to the EMG offset in the M1 contralateral to the movement and bilateral SMAs, where activation was observed also in the muscle contraction. Activated volume in both the rostral and caudal parts of SMA was significantly larger for the muscle relaxation than for the muscle contraction (p < 0.05). The results suggest that voluntary muscle relaxation occurs as a consequence of excitation of corticospinal projection neurons or intracortical inhibitory interneurons, or both, in the M1 and SMA, and both pre-SMA and SMA proper play an important role in motor inhibition.

Adult↗

PubMed1999

Cortical mechanisms underlying point localization of pain spot as studied by event-related potentials following CO2 laser stimulation in man.

To elucidate cortical mechanisms underlying point localization of a pain spot, we investigated event-related potentials (ERPs) while using a CO2 laser beam to apply a pain stimulus to the hand dorsum in 16 healthy men. The stimulus spot (pain spot) was shifted for each stimulus, while the subject was requested to identify the stimulated spot as accurately as possible and to use a pointer in the non-stimulated hand to indicate the corresponding spot on a figure of a hand that was projected onto a screen (localization condition). For the control condition, the subject pointed to a single predetermined spot, regardless of the location of the stimulation (control motor task condition). Electroencephalograms were recorded from 21 electrodes, referenced to the linked earlobes, and were averaged time-locked to the stimulus onset for each task separately. Under the control rest condition (neither point localization nor motor task), only two early components (N2 and P2) were recorded. During the control motor task condition (no point localization), in addition to N2 and P2, a steep negative-going slope was recorded at the fronto-central region. Exclusively during the localization condition, a positive peak (647 ms, 5.6 microV for the left and 634 ms, 5.7 microV for the right hand stimulation) was identified; this was maximal at the midline centro-parietal area and distributed symmetrically over the scalp. It is suggested that the late positive component detected exclusively during the localization task is related to the somatotopic point localization of the pain spot. From the distribution of this ERP, the task most likely involves bilateral activation of the superior parietal cortices.

Adult↗

PubMed1999

Evidence for attenuation of gonadotropin pulse frequency in hypergonadotropic women with estradiol secretion in the menopausal transition.

To investigate neuroendocrine interventions for climacteric symptoms in peri- and post-menopausal periods, the association between endocrine status and symptoms was examined in 519 peri- and post-menopausal women with climacteric symptoms. Furthermore, we evaluated the nature of putative disturbances in pulsatile gonadotropin (FSH and LH) secretion in 14 hypergonadotropic women with estradiol secretion and 16 hypergonadotropic women with hypoestrinism. We observed that 68.6% (356/519) of women with climacteric symptoms and 49.2% (121/246) of women in good health showed hypergonadotropinemia, and that 39.3% (140/356) of hypergonadotropic women with climacteric symptoms and 23.1% (28/121) of healthy women (controls) showed estradiol secretion (p < .002). In particular, the endocrinological profile of hypergonadotropinemia with estradiol secretion was observed in 67.1% (60/92) of pre-menopausal women with climacteric symptoms, approximately 2 x higher than that in healthy women (p < .005). Mental symptoms were observed at a significantly higher incidence in women with the endocrinological profile of hypergonadotropinemia with estradiol secretion compared with that in women with hypergonadotropic hypoestrinism showing a symptomatic profile, namely 25.0 versus 6.9% for mood lability (p < .001), and 21.4 versus 9.3% for anxiety symptoms (p < .001). Moreover, in vivo FSH and LH pulse frequencies were observed in only 14.3 and 18.6% of women with hypergonadotropinemia with estradiol secretion whereas such pulses were observed in all women with hypergonadotropic hypoestrinism. We also observed FSH and LH pulse frequencies in hypergonadotropinemia with estradiol secretion 0.14 +/- 0.35 and 0.29 +/- 0.45/3 h, respectively compared with those in hypergonadotropinemia without estradiol secretion 2.25 +/- 0.91 and 2.81 +/- 0.73/3 h, respectively (p < .001). Such findings are considered to be consistent with diminished hypothalamic GnRH impulse strength. In summary, we infer that decreased pulse frequencies in FSH and LH secretion are due to decreased hypothalamic GnRH impulse strength in women with the endocrinological profile of hypergonadotropinemia with estradiol secretion. As the potential mechanisms of this finding, it should be considered that specific endocrine environments damage the pulse generator mechanism in the diencephalon, and that changes occur in the pituitary responsiveness to GnRH (changes in receptor function).

Adult↗

PubMed1999

Signal separation of background EEG and spike by using morphological filter.

A signal separation method for extracting background electroencephalogram (EEG) from EEG containing spikes was proposed. Morphological filters were designed for extracting spike waveforms, and then the background EEG was obtained by subtracting the detected spike waveforms from the EEG with spike. The proposed method was evaluated by using simulated EEG data, which consisted of a summation of EEG without spike and model waveform of typical spike. The background EEG separated by the method was processed by the automatic background EEG interpretation.

Adult↗