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Biomedical subjects

Y Kikuchi

Publications and source records attributed to Y Kikuchi.

At least 433 records · Page 24Linked to original sources
PubMed1994

Identification of the bphA4 gene encoding ferredoxin reductase involved in biphenyl and polychlorinated biphenyl degradation in Pseudomonas sp. strain KKS102.

The nucleotide sequence of the downstream region of the bph operon from Pseudomonas sp. strain KKS102 was determined. Two open reading frames (ORF1 and ORF2) were found in this region, and the deduced amino acid sequence of ORF2 showed homology with the sequences of four ferredoxin reductases of dioxygenase systems. When this region was inserted just upstream of the bph operon, which does not contain a gene encoding ferredoxin reductase, biphenyl dioxygenase activity was detected. The 24- and 44-kDa polypeptides predicted from the two open reading frames were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Crude extract which contained the products of ORF2 and bphA1A2A3 showed cytochrome c reduction activity. These data clearly suggest that ORF2 encodes ferredoxin reductase. The deduced amino acid sequence of ORF1 does not show significant homology with the sequences of any other proteins in the SWISS-PROT data bank, and the function of ORF1 is unknown.

Amino Acid Sequence↗
PubMed1994

Effects of submental stimulation for several consecutive nights in patients with obstructive sleep apnoea.

BACKGROUND: It has previously been reported that short term submental stimulation can reduce the frequency of apnoea and improve sleep architecture in patients with obstructive sleep apnoea. The effects of submental stimulation during consecutive nights on apnoea or on daytime sleepiness have not, however, been studied. METHODS: Patients with obstructive sleep apnoea were studied by polysomnography on a control night, for five consecutive nights of submental stimulation, and on three following nights (n = 8). A multiple sleep latency test (MSLT) (n = 8) and measurement of the upper airway resistance (n = 5) were performed during the day after the polysomnographic study, on the control night, and on the fifth stimulation night. In an additional five patients with obstructive sleep apnoea, matched for age, sex, and weight, the effects of two nights of stimulation were examined for comparison. Submental stimulation began when an apnoea lasted for five seconds and stopped with the resumption of breathing as detected by oronasal flow. RESULTS: The apnoea index, the number of times per hour that SaO2 dropped below 85% (SaO2 < 85%/hour), and the total apnoea duration expressed as a percentage of total sleep time during stimulation nights decreased to approximately 50% of the corresponding values on the control night. This improvement persisted for at least two nights after the five consecutive stimulation nights, but not after the two consecutive stimulation nights. Sleep architecture and MSLT following the stimulation nights improved but upper airway resistance did not change. CONCLUSIONS: Submental stimulation for five consecutive nights in patients with obstructive sleep apnoea improved the breathing disturbance, sleep quality, and daytime sleepiness. The effect lasted for the following two nights, but did not completely abolish the sleep disordered breathing.

Adult↗
PubMed1994

Mechanism of eosinophil infiltration in the patient with subcutaneous angioblastic lymphoid hyperplasia with eosinophilia (Kimura's disease). Mechanism of eosinophil chemotaxis mediated by candida antigen and IL-5.

Kimura's disease is a chronic granulomatous disease of unknown etiology. Although eosinophilia is one of the characteristic features in this disease, little is known about the mechanism of eosinophilia. In the present study it was demonstrated that interleukin-5 (IL-5) was produced and released from the site of a granuloma and lymph nodes after stimulation with candida antigen. It was also shown that peripheral blood eosinophils from patients with Kimura's disease contained a large proportion of hypodense eosinophils and that their viability was prolonged. These results strongly suggest that locally produced IL-5 induced by candida antigen contributes to the eosinophilia in this disease.

Adult↗
PubMed1994

Endometriotic tissues produce immunosuppressive factors.

In order to study the possible role of the immune functions in the pathogenesis of endometriosis, effects of supernatants from endometrial and endometriotic tissue cultures on the natural killer (NK) activity were examined by determining the lymphocyte cytotoxicity toward an erythroleukemic cell line (K562). Endometrial and endometriotic tissues were obtained at the time of operation from patients with ectopic endometriosis or uterine myoma. The normal peritoneum and myoma tissues were used as controls. The supernatants obtained by culturing the ectopic endometriotic tissues for 24-48 h had significant (p < 0.01) suppressive effects on NK activity of peripheral blood lymphocytes (PBL) from a healthy woman, compared to the supernatants from the normal peritoneum and the myoma tissues. There was no significant difference between NK activities of PBL from patients with ectopic endometriosis and age-matched healthy women. However, the NK activity in patients with low NK status before surgery was significantly elevated after surgery while that in patients with normal NK status before surgery was not changed. Although PBL from the same healthy women could significantly lyse the endometrial cells, the ability was about-one-third the level at which they could lyse K562 cells. These results suggest that the immunosuppressive factors secreted by endometriotic tissues may be involved in the local implantation and development of ectopic endometriosis.

Adult↗
PubMed1994

Effects of prostaglandin E2 inhalation on hypercapnic response in normal subjects.

It is known that the ventilatory response to carbon dioxide (CO2) is increased in asthmatics with airway obstruction. Increased vagal afferent activity as well as increased airway resistance have been postulated as the causative mechanisms. However, whether increased vagal afferent activity without bronchoconstriction increases the ventilatory response to CO2 has not been investigated in humans. We examined the effects of prostaglandin E2 (PGE2) inhalation, which is known to stimulate vagal afferent receptors in the lung without an increase in airway resistance, on the respiratory response to CO2 in seven healthy male subjects. Either physiologic saline or PGE2 (100 micrograms/ml) was inhaled through a Bird nebulizer for 3 min. Twenty minutes after each inhalation, the responses of minute ventilation (VE) and occlusion pressure (P0.1) to hyperoxic hypercapnia were measured. Both the relationships between VE and P0.1 to an increase in tension of end-tidal CO2 (PETCO2) were analyzed by linear regression. Although the mean value of respiratory resistance after PGE2 (3.0 cm H2O/L/s +/- 0.4) did not differ significantly from that after saline (3.1 cm H2O/L/s +/- 0.4), inhaled PGE2 significantly increased the hypercapnic response. This result suggests that the increased vagal afferent activity per se plays an important role in increasing the hypercapnic ventilatory response in humans.

Administration, Inhalation↗
PubMed1994

Prevalence and pathogenesis of silent myocardial ischemia following myocardial infarction.

The objective of this study was to examine the prevalence and pathogenesis of silent myocardial ischemia during exercise following myocardial infarction. Exercise-induced myocardial ischemia was assessed by 201Tl-SPECT (single photon emission computed tomography) 4.5 weeks after acute myocardial infarction in 229 patients. Exercise-induced myocardial ischemia occurred in 109 patients (48%), and 72 (32%) had silent ischemia. Although the prevalence of multivessel coronary artery disease was similar between patients with silent and symptomatic ischemia, the size of reversible myocardial ischemia was larger in patients with symptomatic ischemia than in those with silent ischemia (21.3 +/- 3.0% vs 13.2 +/- 1.9% of LV, p < 0.05). The incidence of reversible ischemia remote from the infarct area was higher in patients with symptomatic ischemia than in those with silent ischemia (30% vs 17%, p < 0.10). The cause of silent ischemia after myocardial infarction may be closely related to the smaller size of reversible myocardial ischemia. Ischemia remote from, or adjacent to, the infarct area could be a factor in determining the presence or absence of pain.

Coronary Angiography↗
PubMed1994

Statistical issues on the no-observed-adverse-effect level in categorical response.

The determination of the value of the no-observed-adverse-effect level (NOAEL) when observed responses can be categorized by severity (categorical data) and sample sizes are small is discussed. The common situation of only two categories, where only the presence or absence of an effect is observed, is addressed first (dichotomous data). Three tests for dichotomous data are critically examined, including the Brown-La Vange test, a modified version of that test, and Dunnett's multiple comparison test. Although the modified test is an improvement, all three procedures have shortcomings in determining the value of the NOAEL, particularly when the sample size is small. An alternative method is suggested, based on the Akaike information criterion (AIC), which performs well. This method is extended to severity data with an arbitrary number of categories. Use of a dose-response curve for the NOAEL is discussed.

Data Interpretation, Statistical↗
PubMed1994

Oxygen consumption of respiratory muscles in patients with COPD.

We measured the oxygen consumption (VO2) of respiratory muscles in 8 COPD patients and 12 age-matched healthy subjects using a closed circuit device which allows a continuous increase in external dead space and is equipped with a 9-L Collins spirometer. Furthermore, we measured simultaneously mouth occlusion pressure at 0.1 s of inspiration (P0.1), minute ventilation (VE), and other ventilatory parameters during the measurement of total VO2 (VO2 tot). We found that the logarithm of VO2tot (logVO2tot) had a good correlation with VE in both groups. The mean slope of the regression line of logVO2tot and VE (delta logVO2tot/delta VE) of COPD patients was significantly higher than that of normal subjects (p < 0.001). However, the mean Y-intercept (metabolic VO2[VO2met]) of the regression lines did not differ between the two groups. The P0.1 in COPD patients was higher than that in normal subjects at the corresponding dead space loading. However, the VE did not differ between the two groups except for at rest and the first 1 min after dead space loading. These results suggest that the VO2 of respiratory muscles in patients with COPD is higher at given ventilation compared with that in age-matched normal subjects and that this increased VO2 partly may be due to an augmented ventilatory drive.

Aged↗
PubMed1994

Upper airway muscle activity during REM and non-REM sleep of patients with obstructive apnea.

We measured electromyograms (EMGs) of genioglossus muscle (GG) and inspiratory intercostal muscle (IIM) in both rapid eye movement (REM) sleep and non-REM sleep of 12 patients with obstructive sleep apnea (OSA) to examine the influence of different sleep stages on upper airway muscle activity during sleep apnea. Quantifications of both muscle activities were assessed by their individual peak amplitude of integrated inspiratory EMG. Genioglossus and IIM activities showed a qualitatively similar cyclic change with an alteration of apneic and ventilatory phases during both non-REM and REM sleep. Both muscle activities increased gradually in the late apneic phase and reached each peak at the opening of the upper airway and, subsequently, decreased gradually. There were no significant differences in both muscles activities in either the ventilatory or early apneic phase between non-REM sleep and REM sleep. On the other hand, GG and IIM activities in the late apneic phase during REM sleep were significantly lower than those during non-REM sleep. The relative activity of GG to IIM in the late apneic phase was significantly lower during REM sleep than that during non-REM sleep. These results indicate that upper airway and intercostal muscle activation in the later apneic phase during REM sleep were inhibited compared with those during non-REM sleep and that this inhibition was observed predominantly in upper airway muscles.

Adult↗
PubMed1994

Effects of unilateral phrenic nerve denervation on diaphragm contractility in rat.

We examined the early effects of phrenic nerve denervation on the diaphragm muscle 1, 3, 7 and 14 days after unilateral denervation in rats. In the denervated hemidiaphragms, force frequency curves at 3, 7 and 14 days decreased significantly by 51%, 50% and 38% respectively of the peak tension of the force frequency curves of the diaphragms of rats with sham operation. Twitch tensions increased significantly at 14 days, and contraction times and half relaxation times slowed significantly at 3, 7 and 14 days. The tensions of denervated diaphragms at 5 min during the fatigue runs was significantly increased at 14 days. As determined by histological staining, the mean cross sectional area of fast-twitch fibers (type II) decreased significantly from 2,742 (sham) to 1,599 microns (14 days), but that of the slow-twitch fibers (type I) did not change significantly during the same period. These findings suggest that, during the first two weeks of denervation, fast twitch fibers (type II) atrophy more rapidly than slow twitch fatigue resistant fibers (type I), as confirmed by the contractile properties and histological findings.

Adenosine Triphosphatases↗
PubMed1994

[Effects of handgrip work and heat load on heart rate variability].

The purpose of the present study was to evaluate cardiac sympathetic (SNS) and parasympathic (PNS) nervous system activities during isometric continuous and intermittent handgrip with power spectrum analysis of heart rate variability (HRV). Eight healthy men performed work at 10% maximum voluntary contraction. The sequence of tests included three different work patterns: 1) the continuous handgrip for 30 min, 2) the intermittent handgrip (10 sec contraction +5 sec relaxation) for 45 min, 3) the intermittent handgrip (10 sec contraction +10 sec relaxation) for 60 min. These experiments were performed at two different heat loads (25 degrees C and 40 degrees C, R.H. 50%). To evaluate HRV, low frequency component (0.03-0.15Hz: LFP) and high frequency component (0.15-0.5Hz: HFP) power were calculated. The SNS and PNS activities were evaluated by LFP/HFP and HFP/(HFP + LFP), respectively. Summary of the results was shown below. 1) The change of the SNS and PNS activities were not significant among the different work patterns, due to the lower work load in the present experiment. 2) The increase of HR at 25 degrees C was mediated primarily by the decrease of the PNS activities during the work periods. 3) The effects of heat loads on the SNS and PNS activities were significant. Briefly, at the same work pattern, the SNS activities at 40 degrees were higher than those at 25 degrees C, but the PNS activities at 40 degrees C were lower than those at 25 degrees C.

Adult↗
PubMed1994

[Localized muscular load to different work patterns and heat loads during handgrip].

The physiological responses and the magnitude of perceived fatigue (MPF) were estimated from eight healthy men during isometric continuous and intermittent handgrip at 10% maximum voluntary contraction (MVC). The physiological responses involved electromyogram (EMG), heart rate (HR), mean blood pressure (MBP) and forearm blood flow during contraction (FBFC) and relaxation (FBFR). The sequence of tests included three different work patterns: 1) continuous handgrip for 30 min, 2) intermittent handgrip (10 sec contraction +5 sec relaxation) for 45 min, 3) intermittent handgrip (10 sec contraction +10 sec relaxation) for 60 min. These experiments were performed on two different heat loads (25 degrees C and 40 degrees C, H.R. 50%). The results were as follows: 1) The localized muscle fatigue in the forearm was observed during the work periods. 2) The mean frequency of EMG was higher at 40 degrees C than 25 degrees C. 3) FBFR was significantly lower than FBFC at 40 degrees C. 4) MPF and MBP were little influenced by the heat load. 5) MPF correlated well with both HR and MBP.

Adult↗
PubMed1994

[Responses of electroencephalogram to different odors].

The responses of electroencephalogram (EEG) to different odors and their densities were studied on four men and two women at rest while sitting. The odors examined were citrus, floral and lavender, and their densities were 100 ppb and 200 ppb. The odors were released for ten minutes from a duct to fill the room completely. The subjective estimation indicated that citrus had a tendency to be the most comfortable odor in this study, but it was not significant. To evaluate changes of EEG, the power spectra of frequency-fluctuation of alpha wave (Fz) and the rate of alpha, beta, and beta/alpha wave (Oz, Fz) were calculated. The rate of alpha wave (Oz) in the period of giving out the citrus at 100 ppb was significantly (p < 0.05) higher than that of the lavender. The rate of beta wave (Oz) in the period of giving out the floral at 200 ppb was significantly (p < 0.05) higher than that of the lavender. The regression coefficient of the power spectra of frequency-fluctuation of alpha wave in the period of giving out the lavender at 100 ppb was significantly higher than those in the other periods of the experiment. The regression coefficient of the power spectra of frequency-fluctuation of alpha wave for lavender given out at 200 ppb was significantly (p < 0.01) higher than those for the other odors given out. It seems that the regression coefficient of the power spectra of frequency-fluctuation of alpha wave can be used for the evaluation of psychophysiological responses.

Adult↗
PubMed1994

Classification of body shape of male athletes by factor analysis.

The purpose of this study was to evaluate the body shape of athletes in comparison with adult non-athletes by factor analysis. The subjects were 210 male adult non-athletes and 485 male high school age and adult athletes participating in 13 different sporting events. Physique, skinfold thickness and body composition of each subject were measured. Measured values from adult non-athletes were analyzed by factor analysis, and body shape of the athletes was then analyzed according to these factors. The results are summarized as follows: 1. Four main factors, that is, body fat, mass, leg length to height ratio and length, which could explain 88.5 percent of total variance, were extracted from the measured values from adult non-athletes. 2. Similarity of body shape between sporting events was analyzed by cluster analysis. Body shape of the athletes could be classified into 3 categories: muscular and well-balanced type; rich muscular and large-built type; and rich muscular and long-torso type. Compared with adult non-athletes, male athletes had less body fat and greater mass except for long-distance runners. The present results suggested that the athletes had body shapes suitable to their sporting events.

Adult↗
PubMed1994

[Bronchial asthma and desaturation--assessment by pulse oximetry].

In the first study, we used pulse oximetry to continuously measure SpO2 and pulse rate in inpatients with paroxysmal attacks of acute asthma. Desaturation and increases in pulse rate occurred during coughing, urination, defecation, eating, and sleeping. Desaturation was most severe and frequent when peak expiratory flow was in the red zone. When it was in the yellow zone or blue zone, desaturation was less severe and less frequent. In the second study, outpatients experiencing exacerbations of chronic asthma and inpatients experiencing acute asthmatic attacks inhaled of a beta 2-stimulant via an ultrasonic nebulizer and were monitored with pulse oximetry. In the former, SpO2 either did not change or increased, but in the latter SpO2 decreased markedly when patients were in the red zone. Therefore, when patients inhale a bronchodilator during an acute asthmatic attack they should be carefully monitored with pulse oximetry. In the third study, pulse oximetry was used to measure saturation in outpatients who were suspected of having hyperresponsive airways and had undergone an airway hyperresponsiveness test with an Astograph. Almost all of those who had desaturation of more than 4% from were markedly hyperresponsive. The degree of desaturation and the percent change in respiratory resistance were significantly correlated. In conclusion, pulse oximetry can be useful in the short-term and long-term management of asthma tic patients.

Adolescent↗
PubMed1994

Anthropometrical data of middle-aged Japanese women for industrial design applications.

Despite the growing importance of human interface design, and despite the growing number of working women, no considerations have been given to women's working spaces and tools. Their designs are based on men's anthropometrical data, and this does not assure safety and amenity of women's working environments. Moreover, few data on women's body measurements are available. The Research Institute of Human Engineering for Quality Life is carrying out an ergonomic anthropometrical study on a large number of Japanese people to create a database for industrial use. The fee for the use of these data is, however, making it very difficult to profit from their acquisition. Therefore, we conducted an anthropometrical study for industrial design use on middle-aged female subjects, who are in the most difficult age group to access. This report should be useful in designing working spaces and tools for women as laborers as well as users.

Adult↗
PubMed1994

A trial to discriminate spontaneous regression from non-regression cases during mass screening for neuroblastoma.

We tried to discriminate between cases of spontaneous regression and non-regression during mass screening for neuroblastoma, taking advantage of differences in respect to the urinary homoranillic acid/vanillyl mandelic acid (HVA/VMA) ratio and the original tumor site among true positive, false negative and natural occurrence cases. After classifying them into a total of six groups depending on the two factors, ratio: < 1, 1-2 or > or = 2 and tumor site: adrenal or extra-adrenal in origin, we calculated the mathematical probability of a given true positive case being one of spontaneous regression. A tumor of extra-adrenal origin was likely to regress spontaneously, especially one with an HVA/VMA ratio < 1 or > or = 2 (82.2-100%). A tumor of adrenal origin with an HVA/VMA ratio < 1 seemed unlikely to regress spontaneously (0-4%). The present method, employing simple preoperative information, would be useful in future for the selection of true positive cases which should be observed without treatment.

Adrenal Gland Neoplasms↗