PubMed Health⌕ Search

Biomedical subjects

Shinichi Okabe

Publications and source records attributed to Shinichi Okabe.

9 recordsLinked to original sources
PubMed2006

Morphologic analyses of mandible and upper airway soft tissue by MRI of patients with obstructive sleep apnea hypopnea syndrome.

STUDY OBJECTIVES: To evaluate the morphological features of the mandible and the volume of the upper airway soft tissues in determining the anatomical risk factors for the upper airway in Japanese male patients with obstructive sleep apnea hypopnea syndrome (OSAHS). METHODS: Five morphological parameters of the mandible at the mandibular base plane and three volumetric parameters of the upper airway soft tissue were analyzed using three-dimensional (3D) magnetic resonance imaging software in 31 OSAHS and 20 controls. RESULTS: There were no significant differences between the two groups in mandibular internal width (the distance between the internal right and left gonia [IRG and ILG]) and mandibular bony thickness. However, the patients with OSAHS had a significantly wider mandibular divergence (the angle between the spina mentalis (SM)- IRG line and SM- ILG line), a smaller mandibular internal length (the perpendicular distance from SM to the RG- LG line), and a smaller area than the normal subjects at the mandibular base plane. There were no significant differences in these morphological parameters for the mandible between obese and nonobese OSAHS patients. The volumes of the tongue, soft palate, and lateral pharyngeal walls were not significantly different between the OSAHS and the control groups. CONCLUSIONS: Japanese male OSAHS patients had specific anatomical features in the bottom part of the mandible; however, obesity seemed to be a less significant risk factor. Investigators and clinicians must realize that ethnicity may modify the effects of obesity and abnormal craniofacial anatomy as risk factors for the pathogenesis of OSAHS.

Asian People↗
PubMed2006

Mice with blunted hypoxic ventilatory response are susceptible to respiratory disturbance during hypoxia.

Hypoxia causes a life-threatening situation, and the ventilatory response to hypoxia plays an important role in preventing death. We have hypothesized that persons with a blunted hypoxic ventilatory response may have a weak defense response to hypoxic episodes and be susceptible to fatal respiratory disturbances. However, precise correlations between the hypoxic ventilatory response and respiratory disturbances are not well understood. In the present study we examined the hypoxic and hypercapnic ventilatory responses in nine inbred mouse strains (A/J, AKR/N, BALB/c, C3H/He, C57BL/6, DBA/2, NZW, SWR/J, and 129Sv). Breathing frequency, tidal volume and minute ventilation of unanesthetized and unrestrained mice were assessed by whole body plethysmography. Age-matched mice were exposed for 3 min to 10% O(2) in N(2) gas or 10% CO(2) in hyperoxic gas to determine the acute ventilatory response to chemical stimuli. Basal respiratory variables and hypoxic ventilatory responses differed among the strains, but the hypercapnic ventilatory response did not differ. The hypoxic ventilatory response was the highest in AKR/N mice and the lowest in SWR/J mice. These findings suggest that genetic factors may have influenced the hypoxic ventilatory response but not the hypercapnic ventilatory response. To examine the effects of severe hypoxic stress on the respiratory cycle, we exposed the strain with the highest or lowest hypoxic ventilatory response to 6% O(2) in N(2) until the onset of apnea. The "appearance time of apnea", which is defined as the time from the hypoxic loading to the onset of apnea, was shorter in the SWR/J strain than in the AKR/N strain. We suggest that a lower hypoxic ventilatory response may be a risk factor for apnea under hypoxia.

Adaptation, Physiological↗
PubMed2005

Digital recording and analysis of esophageal pressure for patients with obstructive sleep apnea-hypopnea syndrome.

To evaluate sleep-related obstructive breathing events in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS), we developed a technique for digital recording and analysis of esophageal pressure (Pes) and elucidated the Pes parameters. Pes was recorded overnight with a microtip-type pressure transducer in 74 patients with OSAHS. Simultaneously, in all patients digital polysomnography was recorded. The mean nadir end-apneic Pes swing (Pes Nadir) ranged from -20.2 to -147.4 cmH(2)O, with a mean of -53.6+/-2.9 cmH(2)O. Correlation of the mean Pes Nadir indicated a linear relationship with the mean ratio of maximal Pes swing to apnea duration (r(2)=0.70) and the mean area of the Pes (Pes Area) (r(2)=0.82). Significant correlations were noted between the mean Pes Nadir and apnea-hypopnea index (AHI, ranging from 7.9 to 109.5 per hour; r(2)=0.66), minimum SpO(2) (r(2)=0.60), oxygen desaturation index (ODI) of more than 3 (r(2)=0.65), arousal index (r(2)=0.54), and between the mean Pes Area and AHI (r(2)=0.63), minimum percutaneous arterial oxygen saturation (SpO(2); r(2)=0.57), ODI (r(2)=0.69), and arousal index (r(2)=0.41). Pes parameters were found to be significant in the evaluation of the severity of the respiratory effort during the sleep-related obstructive breathing events for patients with OSAHS.

Electroencephalography↗
PubMed2004

The effect of upper airway structural changes on central chemosensitivity in obstructive sleep apnea-hypopnea.

We examined the efficiency of upper airway structural changes in uvulopalatopharyngoplasty and/or tonsillectomy on central chemosensitivity, and whether the outcome of such surgeries can be predicted by the central chemosensitivity in obstructive sleep apnea-hypopnea syndrome (OSAHS) patients. In 11 patients with OSAHS group, the average of the hypercapnic ventilatory response (HCVR) slope was 1.93 +/- 0.20 L/min/mm Hg preoperatively and 1.78 +/- 0.22 L/min/mm Hg postoperatively. The average of the mouth occlusion pressure at 0.1 second after the onset of inspiration (P (0.1)) slope was 0.47 +/- 0.06 cm H (2)O/mm Hg and 0.44 +/- 0.08 cm H (2)O/mm Hg, before and after surgery, respectively. There were no significant differences before and after treatment, although OSAHS was improved by these surgeries. In control group with 5 patients, the HCVR slope and P (0.1) slope also showed no significant difference before and after the procedure. When we divided the 11 OSAHS patients into 7 responders (apnea-hypopnea index < 20 events/h and > 50% reduction) and 4 poor responders, there was a significant difference between the average HCVR slope of responders (1.59 +/- 0.21 L/min/mm Hg) and that of poor responders (2.52 +/- 0.20 L/min/mm Hg). We saw no significant difference in physiologic (age, body mass index, one-piece tonsil weight), blood gas values, cephalometric, spirometric, or sleep parameters.

Adult↗
PubMed2003

Nasal continuous positive airway pressure improves quality of life in obesity hypoventilation syndrome.

We studied the quality of life of obesity hypoventilation syndrome (OHS) by comparing it with age- and body mass index-matched patients without hypoventilation and age-matched obstructive sleep apnea (OSA) patients with body mass index (BMI) under 30, and the efficacy of nasal continuous positive airway pressure (CPAP) therapy for 3 to 6 months on the quality of life in these patients. Prospectively recruited patients from six sleep laboratories in Japan were administered assessments of the general health status by the Short-Form 36 Health Survey (SF-36) and subjective sleepiness by the Epworth Sleepiness Scale (ESS). Compared with matched healthy subjects, OHS and OSA patients not yet treated had worse results on the ESS scores and the SF-36 subscales for physical functioning, role limitations due to physical problems, general health perception, energy/vitality, role limitations due to emotional problems, and social functioning. The ESS scores of OHS patients were worse than those of the OSA groups including the age- and BMI-matched OSA patients. In the SF-36 subscales of OHS patients, only the subscale of social functioning showed worse results compared with that of BMI-matched OSA patients. After 3 to 6 months of treatment, ESS scores and these SF-36 subscales in all three patient groups improved to the normal level. These results suggested that the quality of life of OHS before nasal CPAP was significantly impaired and that nasal CPAP for OHS improved the quality of life associated with the improvement of daytime sleepiness to the level of the other OSA patients.

Adult↗
PubMed2003

Can nasal continuous positive airway pressure decrease clinic blood pressure in patients with obstructive sleep apnea?

Obstructive sleep apnea (OSA) is commonly associated with systemic hypertension and now recognized as an independent risk factor for daytime hypertension. We aimed to study the short- and long-term effect of nasal continuous positive airway pressure (CPAP) in hypertensive and normotensive patients with OSA. Forty-six patients with moderated to severe OSA were treated with nasal CPAP and followed after one year of treatment. Clinic blood pressure, heart rate, and body weight were taken before and followed up for one year after beginning nasal CPAP. In this study 25 patients with OSA were found to have hypertension (54.3%). The hypertensive group showed a significant reduction in clinic blood pressure after nasal CPAP, whereas the normotensive group showed no changes. The subgroup of hypertensive patients with OSA who had no anti-hypertensive medication revealed a decrease in clinic blood pressure comparable to those with anti-hypertensive drugs. The heart rate was not significantly changed in any patients. There was no significant correlation between the decrease in body weight and the reduction in blood pressure. These results suggest that nasal CPAP alone might have a substantial blood pressure lowering effect in hypertensive patients with OSA. This effect could decrease the morbidity and mortality related to cardiovascular complications in patients with OSA.

Adult↗
PubMed2002

Impaired chemosensitivity to hypoxia is a marker of multiple system atrophy.

Sudden death is common in patients with multiple system atrophy (MSA). In its early stages, the cerebellar presentation MSA-C can be indistinguishable from idiopathic late-onset cerebellar ataxia. We studied the hypoxic ventilatory response in MSA-C and idiopathic late-onset cerebellar ataxia patients. Six patients with idiopathic late-onset cerebellar ataxia that later evolved to MSA had impaired hypoxic ventilatory response when minimal autonomic failure was still present, whereas for patients with unimpaired hypoxic ventilatory response their diagnosis remained idiopathic late-onset cerebellar ataxia. The demonstration of impaired hypoxic ventilatory response appears to be a good marker enabling earlier diagnosis of MSA in patients presenting with idiopathic late-onset cerebellar ataxia.

Aged↗
PubMed2002

Pulmonary hypertension in patients with chronic obstructive pulmonary disease: recent advances in pathophysiology and management.

In patients with chronic obstructive pulmonary disease (COPD), pulmonary hypertension (PH) is associated with a worse prognosis. Recently, information has been increasing concerning the cellular and molecular aspects of the pathophysiology of PH in COPD. The most striking finding is the role of vascular endothelial cells and endogenous mediators released by these cells. Endothelial cell-dependent relaxation is impaired in COPD patients with PH. Moreover, vascular remodelling in these patients is mainly responsible for irreversible PH in advanced COPD. Smoking cessation will slow down the progression of the disease process and may prevent the development of PH in COPD. The timing of initiation of long-term oxygen therapy is important for the effective management of PH in COPD. Research on therapeutic agents for the effective treatment of PH is still needed in the management aspect of patients with COPD. This review focuses on the recent advances in our understanding of the pathophysiology and treatment of PH in COPD.

Cardiac Catheterization↗