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Biomedical subjects

W Hida

Publications and source records attributed to W Hida.

At least 37 records · Page 2Linked to original sources
PubMed1995

[Portable home monitoring system in screening for sleep-disordered breathing].

Screening for sleep-disordered breathing is often done in an interview and with a questionnaire. This method is indirect and it appears to underestimate the prevalence of sleep apnea syndrome. Recently, several devices such as the Medilog and Vitalog portable monitoring systems were developed. However, these devices are difficult for patients to operate by themselves, because they include EEG monitoring or measurement of chest and abdominal movement. Therefore, we developed a portable monitoring system that is easier to operate. This system can be used to assess three variables: oronasal airflow, tracheal sound, and electrical activity of the heart. It stores the time of the onset of apnea, apnea duration, and R-R intervals with a built-in microcomputer. Apnea episodes, total apnea time, mean apnea time, and R-R interval are analyzed with a host computer. The sensitivity an specificity of this system are 92.5% and 87.5%, respectively, with an apnea index (AI) of less than 10 episodes/h. Using this device, we found that the prevalence of sleep apnea syndrome among Japanese industrial workers who had an AI of more than 10 episodes was 7.5%. Moreover, from 1984 to 1994 we used this device to monitor 1019 outpatients who complained of sleep disturbances such as snoring, abnormal breathing during sleep, and excessive daytime sleepiness, and found sleep apnea (AI > or = 10) in about 50% of these patients. This monitoring system is useful for screening of outpatients with sleep apnea and for epidemiological studies of sleep apnea. However, it may be necessary to include a non-invasive system for monitoring oxygen saturation in the portable sleep monitor, to detect hypoventilation during sleep.

Adolescent↗
PubMed1994

In vivo release of glutamate in nucleus tractus solitarii of the rat during hypoxia.

1. An attempt has been made to test the hypothesis that, in the caudal part of nucleus tractus solitarii (NTS) where carotid sinus nerve (CSN) afferents project, L-glutamate (Glut) modulates the hypoxic ventilatory response. 2. Unanaesthetized, peripherally chemodenervated (carotid body denervated; CBD) and sham-operated, freely moving rats were used. During peripheral chemoreceptor stimulation by hypoxia (10% O2 for 30 min) or doxapram (Dox) infusion (2 mg kg-1 (30 min)-1), ventilation was recorded and successively, under the same conditions, the extracellular Glut concentration ([Glut]o) in the caudal NTS was measured by in vivo microdialysis. [Glut]o was also measured during hyperoxic hypercapnia (10% CO2-30% O2 for 30 min). 3. Furthermore, the effects on ventilation of exogenous Glut, the NMDA (N-methyl-D-aspartate) receptor antagonist MK-801 or the ionotropic receptor antagonist kynurenate microinjected into the caudal NTS were investigated in sham-operated rats. 4. In sham-operated rats, both ventilation and [Glut]o in NTS were increased during peripheral chemoreceptor stimulation. On the other hand, no increases in either ventilation or Glut release were observed in CBD rats. In spite of ventilatory augmentation during hypercapnia, no response of [Glut]o to hypercapnia was observed in either group. 5. Local Glut application into NTS increased ventilation. Pretreatment with MK-801 or kynurenate reduced the hypoxic ventilatory response. This reduction in ventilation was mainly due to the decrease in tidal volume. 6. These results suggest that hypoxia induced the release of Glut in NTS and that this effect was mediated by arterial chemosensory input.

Animals↗
PubMed1994

Chemosensitivity and perception of dyspnea in patients with a history of near-fatal asthma.

BACKGROUND: Many deaths from attacks of asthma may be preventable. However, the difficulty in preventing fatal attacks is that not all the pathophysiologic risk factors have been identified. METHODS: To examine whether dyspnea and chemosensitivity to hypoxia and hypercapnia are factors in fatal asthma attacks, we studied 11 patients with asthma who had had near-fatal attacks, 11 patients with asthma who had not had near-fatal attacks, and 16 normal subjects. Their respiratory responses to hypoxia and hypercapnia, determined by the standard rebreathing technique while the patients were in remission, were assessed in terms of the slopes of ventilation and airway occlusion pressure as a function of the percentage of arterial oxygen saturation and end-tidal carbon dioxide tension, respectively. The perception of dyspnea was scored on the Borg scale during breathing through inspiratory resistances ranging from 0 to 30.9 cm of water per liter per second. RESULTS: The mean (+/- SD) hypoxic ventilatory response (0.14 +/- 0.12 liter per minute per percent of arterial oxygen saturation) and airway occlusion pressure (0.05 +/- 0.05 cm of water per percent of arterial oxygen saturation) were significantly lower in the patients with near-fatal asthma than in the normal subjects (0.60 +/- 0.35, P < 0.001, and 0.16 +/- 0.08, P < 0.001, respectively) and the patients with asthma who had not had near-fatal attacks (0.46 +/- 0.29, P = 0.003, and 0.15 +/- 0.09, P = 0.004). The Borg score was also significantly lower in the patients with near-fatal asthma than in the normal subjects, and their lower hypoxic response was coupled with a blunted perception of dyspnea. CONCLUSIONS: Reduced chemosensitivity to hypoxia and blunted perception of dyspnea may predispose patients to fatal asthma attacks.

Adult↗
PubMed1994

Preproenkephalin gene expression in the rat cerebral cortex during chronic tracheal stenosis.

To evaluate whether the endogenous opioid system is activated in the higher brain centre while a chronic resistance to airflow, we examined changes of mRNAs for preproenkephalin (PPE)-A, which is a precursor of enkephalin, and for 70 kD heat shock protein (HSP70) in the cerebral cortex of rat brain during chronic tracheal stenosis. Northern blot revealed that PPE-A mRNA was induced at 3 days of airway stenosis. In situ hybridization revealed that PPE-A mRNA was gradually induced in frontal cortex. The significant induction of PPE-A mRNA was observed at 3 and 7 days. However, no significant induction of HSP70 gene was observed. These results suggest that the endogenous opioid system may be at work as an important compensatory mechanism to reduce the respiratory sensation during chronic respiratory stress.

Animals↗
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

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

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

[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

[Relationship between apneic episodes and destruction of temporomandibular joints in patients with rheumatoid arthritis].

There have been only a few investigational reports of sleep apnea syndrome (SAS) in patients with rheumatoid arthritis (RA), although it may not be a rare condition and may be life-threatening occasionally. The factor precipitating SAS in such patients is thought to be destruction of the temporomandibular joints (TMJs) from RA processes. To assess the relationship of the degree of destruction of the TMJs to the frequency of apnea, we examined them in 10 RA patients who complained of snoring. Those patients were classified as classical RA according to the criteria of American Rheumatism Association. They consisted of 3 males and 7 females with a mean age of 57.8 + 11.0 years and a mean disease duration of 15.9 +/- 9.4 years. In order to numerically evaluate the degree of destruction of the mandibular rami, we quoted a method from the literature (Redlund-Johnell I, Scand J Rheumatol 16:355, 1987) and measured the vertical distance (= ramal height) from the mandibular angle to the palato-occipital line on the lateral view film of the cervical spine in each patient. The mean values of ramal height (RH) of the normal material (we studied in Japanese) are 46.0 mm in males and 38.3 mm in females. There were 8 cases of SAS out of the 10 RA patients studied. Their mean total apneic episode (TAE) was 289.9 mm with a range of 0-611. The mean ratio (%) of RH to mean value of the normal material (%RH) was 68.8 +/- 22.2% for all. There was a significant statistic correlation between TAE and %RH (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Effects of posture on carbon dioxide responsiveness in patients with obstructive sleep apnoea.

BACKGROUND: It is well known that upper airway resistance increases with postural change from a sitting to supine position in patients with obstructive sleep apnoea (OSA). It is not known, however, how the postural change affects the ventilatory and occlusion pressure response to hypercapnia in patients with OSA when awake. METHODS: The responses of minute ventilation (VE) and mouth pressure 0.1 seconds after the onset of occluded inspiration (P0.1) to progressive hypercapnia (delta VE/delta PCO2, delta P0.1/delta PCO2) both in sitting and supine positions were measured in 20 patients with OSA. The ratio of the two (delta VE/delta P0.1) was obtained as an index of breathing efficiency. The postural changes in response to carbon dioxide (CO2) after uvulopalatopharyngoplasty (UPPP) were also compared in seven patients with OSA. RESULTS: There were no significant changes in the resting values of end tidal PCO2, P0.1, or VE between the two positions. During CO2 rebreathing, delta VE/delta PCO2 did not differ between the two positions, but delta P0.1/delta PCO2 was significantly higher in the supine than in the sitting position (supine, mean 0.67 (SE 0.09) cm H2O/mm Hg; sitting, mean 0.57 (SE 0.08) cm H2O/mm Hg), and delta VE/delta P0.1 decreased significantly from the sitting to the supine position (sitting, 4.6 (0.4) l/min/cm H2O; supine, 3.9 (0.4) l/min/cm H2O). In seven patients with OSA who underwent UPPP, delta VE/delta P0.1 improved significantly in the supine position and postural change in delta VE/delta P0.1 was eliminated. CONCLUSIONS: These results suggest that in patients with OSA the inspiratory drive in the supine position increases to maintain the same level of ventilation as in the sitting position, and that the postural change from sitting to supine reduces breathing efficiency. Load compensation mechanisms of patients with OSA appear to be intact while awake in response to the rise in upper airway resistance.

Female↗
PubMed1993

Upper airway muscle activity during sustained hypoxia in awake humans.

To examine the effects of sustained hypoxia on upper airway and chest wall muscle activity in humans, we measured genioglossus muscle (GG) activity, inspiratory intercostal muscle (IIM) activity, and ventilation during sustained hypoxia in 17 normal subjects and 17 patients with obstructive sleep apnea (OSA). The trial of sustained hypoxia was performed as follows: after an equilibration period of 3 min, isocapnic hypoxia (arterial O2 saturation = 80 +/- 2%) was maintained for 20 min. GG EMG was measured with a fine-wire electrode inserted percutaneously, and IIM EMG was measured with surface electrodes. Ventilatory response to sustained hypoxia was initially increased and subsequently decreased. Stable phasic GG activity during spontaneous tidal breathing was observed in 6 normal subjects and 10 patients with OSA. Responses of GG and IIM activities to sustained hypoxia showed a biphasic response qualitatively similar to the ventilatory response in these 16 subjects. The absolute value of the subsequent decline in GG activity was similar to that of the initial increase, whereas the subsequent decline in IIM activity was smaller than that of the initial increase. Percent GG activity was significantly lower than both percent IIM activity and percent minute ventilation during the decline and plateau phases. There were no significant differences in ventilatory and EMG responses between the normal subjects and the patients with OSA. We conclude that, during wakefulness, upper airway muscle activity declined to a greater extent than inspiratory pump muscle activity during sustained hypoxia.

Adult↗
PubMed1993

Prevalence of sleep apnea among Japanese industrial workers determined by a portable sleep monitoring system.

We developed a new portable sleep monitoring system and studied the prevalence of sleep apnea syndrome among Japanese industrial workers. This device assessed three kinds of parameters: nasal airflow, tracheal sound and electrocardiogram (ECG), and digitally stored the clock time of the onset of apnea, apnea duration and R-R intervals by a built-in microcomputer. After monitoring, the portable sleep monitor was connected to a host computer, and apneic episodes, the so-called 'apnea index' as apneic episodes corrected by measuring time ('AI') and R-R intervals were analyzed. In 170 inpatients referred to our sleep clinic, sleep monitoring by this device was performed simultaneously with all-night polysomnography, and the sensitivity and specificity of this device was determined under different criteria of the apnea index (AI) (AI > 5, 10, 15 and 20 episodes/h) by polysomnography. In all AI criteria, the sensitivity was more than 90%, and the specificity was also reasonably high. Using this system, successive 2-night home sleep monitoring was performed on 168 healthy workers in one Japanese industrial company, and 159 people (140 males; 19 females) who had successful monitoring were analyzed. The percentage of persons who had 'AI' of more than 10 episodes/h was 7.5%. There were no significant correlations between 'AI' and age, body weight or scores estimated by sleep questionnaires. These results suggest that even in people who are seemingly healthy significant apneic episodes could be detected by the portable home sleep monitoring system. This system may therefore be useful in evaluating the occurrence of sleep apnea syndrome in general populations.

Adolescent↗
PubMed1993

Role of chemical drive in recruiting upper airway and inspiratory intercostal muscles in patients with obstructive sleep apnea.

Upper airway dilating muscle activity increases during apneic episodes in patients with obstructive sleep apnea (OSA). To elucidate the relative contribution of chemical and nonchemical stimuli to augmentation of the upper airway dilating muscle, we measured the response of genioglossus muscle (GG) and inspiratory intercostal muscle (IIM) activities to obstructive apnea during non-REM sleep and compared them with the response to progressive hypoxia and hypercapnia during awake periods in seven male patients with OSA. GG EMG was measured with a wire electrode inserted percutaneously, and IIM EMG was measured with surface electrodes placed in the second intercostal space parasternally. Responses to hypoxia and to hypercapnia were assessed by rebreathing methods in the supine position while awake. Following these measurements, a sleep study was conducted with the EMG electrodes placed in the same locations. The relationship between GG and IIM activities during the cycle of apnea and postapneic ventilation in non-REM sleep was quasi-linear, and the slope of the regression line was significantly greater than those during progressive hypoxia and progressive hypercapnia. The amplitude of GG activity at 70% of maximum IIM activities in the hypoxic test was 140 +/- 20% (mean +/- SEM) during non-REM sleep, which was also significantly greater than that during hypoxia (51 +/- 10%) and that during hypercapnia (59 +/- 15%). These results suggest that nonchemical factors contribute considerably to augmentation of GG activity during obstructive apneic episodes. The nonchemical stimuli may arise from mechanoreceptors activated by upper airway obstruction and behavioral factors associated with change in sleep states.

Adult↗
PubMed1993

Small airway involvement in mixed connective tissue disease.

We studied pulmonary functions in 17 female patients with mixed connective tissue disease (MCTD) to detect early pulmonary involvement in this disease; in 8 of the 17 patients follow-up studies were also performed at 1.2- to 5.9-year intervals. In the first pulmonary function tests, decreases in vital capacity (VC) and diffusing capacity (DLCO) were observed in 6 (35%) and 8 (47%) patients, respectively. The ratio of forced expiratory volume in one second to VC was normal in all the patients, but pulmonary resistance and static compliance were abnormal in 6 (35%) and 10 (59%) patients, respectively. However, frequency dependence of dynamic compliance was found in all 16 patients tested. Moreover, 4 (24%) of the 17 patients had normal DLCO and DLCO-to-alveolar volume ratio (DLCO/VA). Reductions in DLCO and DLCO/VA were significantly correlated with the disease duration. These results suggest that small airway obstruction is an early and frequent indication of functional pulmonary impairment, and that impairment of alveolar gas exchange is progressive in patients with MCTD.

Adolescent↗