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Biomedical subjects

T Akashiba

Publications and source records attributed to T Akashiba.

15 recordsLinked to original sources
PubMed1992

[Pulmonary function and exercise tolerance in patients treated with bone marrow transplantation (BMT)].

We assessed pulmonary function and exercise tolerance in 10 BMT patients. Their underlying disorders were as follows; chronic myeloid leukemia 5 cases, acute lymphoblastic leukemia 2 cases, aplastic anemia, acute myeloid leukemia and non-Hodgkin's lymphoma one case each. Their mean age was 26 +/- 9 years old. When the patients were healthy and free of serious complications and anemia, arterial blood gas examination, pulmonary function tests and incremental treadmill exercise test were examined repeatedly. Although %VC and FEV1.0% kept within normal range, PaO2 at rest, %DLCO, VO2max, VO2max/kg and O2-pulsemax remained low at one year after BMT. There were significant correlations between VO2max and O2-pulsemax [r = 0.955 (p < 0.001)], %VC [r = 0.758 (p < 0.02)], VE/VO2max [r = -0.749 (p < 0.02)] and delta SaO2/VO2/kg [r = -0.731 (p < 0.02)], suggesting that exercise intolerance in BMT patients may be based on both cardiac and gas exchange abnormalities. To evaluate cardiac dysfunction, we compared exercise parameters obtained at an exercise level of 75% predicted heart rate max in five age-matched normal subjects to those in six BMT patients who did not demonstrate desaturation during exercise. As a result, the mean values of VO2max/kg and O2-pulse/m2 in BMT patients were significantly lower than those in normal subjects, suggesting that cardiac dysfunction may be due to insufficiency of stroke volume during exercise. It is concluded that exercise intolerance in BMT patients may be mainly due to cardiac dysfunction.

Adolescent↗
PubMed1992

[Long-term effects and complications of home nasal CPAP therapy for obstructive sleep apnea patients].

We treated 23 patients with obstructive sleep apnea syndrome (OSAS) by nasal continuous positive airway pressure (NCPAP) at home, and examined the long-term compliance, clinical effects, and complications after NCPAP therapy. Nineteen patients continued and four patients discontinued the therapy during the mean observation period of 15 months, and the compliance was 83%. There was no significant difference in age, weight, and sleep data between the compliant group (C) and non-compliant group (NC). The causes of discontinuation of therapy were lack of adaptation to the apparatus (2 cases), improvement of clinical symptoms due to weight reduction (1 case), and induction of asthma attack (1 case). Disappearance of excessive daytime sleepiness, improvement of sleep quality, and disappearance of nocturia were observed in most cases, and disappearance of morning headache and improvement of sexual ability and emotional instability were also observed in several cases. Nine cases (39%) complained of discomfort due to the nasal mask and 6 cases (26%) complained of dryness of the mouth and nose, whereas 10 cases (43%) experienced no adverse effects. No serious complications were observed. These findings suggest that long-term home NCPAP is an effective and safe treatment for OSAS patients.

Humans↗
PubMed1992

[Pulmonary function and pulmonary hemodynamics in obstructive sleep apnea syndrome].

The prevalence and mechanisms of daytime pulmonary hypertension were examined in 24 cases of obstructive sleep apnea syndrome (OSAS). All patients were free from chronic lung disease. They underwent pulmonary function tests and blood gas analysis in the sitting and supine position, hypercapnic ventilatory response test, exercise test and right heart catheterization. Elevation of mean pulmonary arterial pressure (m-PAP) above 20 mmHg was observed in 5 out of 24 cases (20.8%). The group with pulmonary hypertension (PG+: m-PAP = 22.2 +/- 2.7 mmHg) showed marked obesity (p < 0.001), significant decrease of supine FRC/TLC (p < 0.05), increase of supine CC/FRC (p < 0.01), decrease of supine PaO2 (p < 0.02) and desaturation during exercise (p < 0.05) in comparison with the group without pulmonary hypertension (PH-: 13.9 +/- 3.1 mmHg). m-PAP was positively correlated with %IBW and desaturation during exercise (p < 0.01, p < 0.02) and negatively correlated with supine PaO2 (p < 0.01). Various changes in pulmonary function and pulmonary hemodynamics due to obesity seem to lead to daytime pulmonary hypertension of OSAS.

Cardiac Catheterization↗
PubMed1992

[Ventricular performance during exercise in patients with chronic obstructive pulmonary disease (COPD)].

We assessed ventricular performance during exercise in 16 COPD patients and 8 normal control subjects by means of radionuclide equilibrium angiography using technetium-99m as a tracer. Supine exercise on a bicycle ergometer was performed until symptom-limited exhaustion. Data were accumulated for 300 heart beats at rest and 150 heart beats during exercise. We used the standard voxel count method to calculate the ventricular volumes. Age, FEV1.0%, %VC, PaO2 and PaCO2 of the COPD patients were 63 +/- 8 yr, 46 +/- 11%, 69 +/- 18%, 68 +/- 11 Torr and 44 +/- 7 Torr (mean +/- SD), respectively. Systolic dysfunction of both the left and right ventricles was well confirmed in the present study. In 12 patients who also underwent hemodynamic studies, resting total pulmonary vascular resistance index (TPVRI) and mean pulmonary artery pressure (Ppa) significantly correlated with right ventricular end-systolic volume index (RVESVI) obtained by RI angiography; gamma = 0.769 (p less than 0.01) and gamma = 0.631 (p less than 0.05), respectively. A significant relationship was also observed between left ventricular dysfunction and the degree of hypercapnia. In response to exercise testing, 10 of 16 patients exhibited insufficient augmentation of stroke volume, and both left and right end-diastolic volumes decreased in half of 10 patients. It is suggested that cardiac function may be disturbed by mechanical factors such as pulmonary hyperinflation in COPD patients.

Aged↗
PubMed1991

[Upper airway finding on CT scan with and without nasal CPAP in obstructive sleep apnea patients].

The area of upper airway (from the nasopharynx to the hypopharynx) was measured by means of computed tomography (CT) scan in 15 confirmed cases of obstructive sleep apnea (OSA) and in 4 normal controls while they were awake. The minimum cross-sectional area (MA) of the upper airway was 14.7 +/- 20.0 mm2 in OSA patients and 80.0 +/- 33.1 mm2 in normal controls and the difference was statistically significant (p less than 0.01). In OSA patients, MA did not correlate with age, body weight, apnea index, desaturation index, mean nadir-SO2 and lowest SO2. MA was also measured with OSA patients while nasal continuous positive airway pressure (NCPAP) of 10 cmH2O was applied and it was found that MA was significantly widened when NCPAP therapy was performed. We conclude that upper airway narrowing is consistent finding in OSA patients but the degree of narrowing does not correlate with parameters of apnea and gas exchange during sleep, and NCPAP is effective to widen the area of upper airway in OSA patients.

Adult↗
PubMed1991

[Effects of nasal continuous positive airway pressure (NCPAP) on nocturnal renal function in obstructive sleep apnea syndrome (OSAS)].

Nocturnal renal function was examined in 8 patients with obstructive sleep apnea syndrome (OSAS) and the effects of nasal CPAP (NCPAP) on renal function were also studied. Nocturia was observed more than twice in all cases when no treatment was performed, but it disappeared after initiation of NCPAP. Fractional nocturnal urine volume and creatinine clearance decreased significantly from 1.36 +/- 0.15 ml/min to 0.75 +/- 0.20 ml/min (p less than 0.01) and from 116.8 +/- 46.5 ml/min to 101.1 +/- 33.0 ml/min (p less than 0.05), respectively, after initiation of NCPAP. Although the serum Na and creatinine did not change following NCPAP, the urine Na and creatinine changed significantly after NCPAP therapy. The serum renin, aldosterone, and ADH did not change after NCPAP therapy. The significant positive correlation (p less than 0.05) between the fractional nocturnal urine volume and DI, and also significant inverse correlation (p less than 0.05) between the fractional urine volume and %FRC were observed. These results suggest that the abnormal renal function seen in cases of OSAS is related to the hypoxemia during sleep. It was concluded that the nocturnal renal function in cases of OSAS was different from those in normal controls and NCPAP therapy induced the recovery of these abnormalities.

Creatinine↗
PubMed1990

[The effect of short-term nasal CPAP therapy in cases of obstructive sleep apnea syndrome].

Recent studies have shown that nasal CPAP is very effective in the treatment of patients with obstructive sleep apnea syndrome (OSA). To clarify the characteristics of pulmonary function testing and to evaluate the effect of short term nasal CPAP therapy in 13 cases of OSA patients, nasal CPAP was used for 10 to 14 days and polysonography was performed on two consecutive nights without nasal CPAP and at one night with nasal CPAP. Pulmonary function tests and the Uchida-Kraepelin test were performed before the initiation of nasal CPAP therapy and also 7 to 14 days after the nasal CPAP therapy. Apnea index reduced significantly in all cases from 5.10 +/- 19.6 episodes/hour without therapy to 3.1 +/- 3.5 with nasal CPAP (p less than 0.001). Nasal CPAP significantly reduced the frequency of obstructive (p less than 0.001) and mixed apnea (p less than 0.01), but the frequency of central apnea did not change with nasal CPAP. During the nasal CPAP, mean nadir SaO2 rose from 87.3 +/- 2.9% to 92.7 +/- 1.1% (p less than 0.001) and the lowest SaO2 rose from 73.3 +/- 6.4% to 92.0 +/- 2.1% (p less than 0.001). Before the nasal CPAP therapy, daytime PaO2 was 80.6 +/- 6.4 Torr and closing capacity (CC)/FRC ratio was higher when patients were in a supine than in a sitting position. After short term nasal CPAP therapy, daytime PaO2 increased significantly (p less than 0.001), and FRC/TLC in a supine position increased and CC/FRC in a supine position decreased in some patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Relationship between pulmonary functions and sleep respiratory abnormalities in obstructive sleep apnea syndrome].

Pulmonary function tests were performed in 18 cases of obstructive sleep apnea in supine and sitting positions and the relationship between pulmonary function and polysomnographic data was analyzed. %FRC and PaO2 were reduced in the supine position compared with those in the sitting position. It was suggested that the reduction of PaO2 was mainly caused by the elevation of CC/FRC ratio in supine position. The relationship between pulmonary function data and polysomnographic data were analyzed, and an inverse relationship between %FRC in sitting position and desaturation was observed and also a positive relationship between PaO2 in the supine position mean-nadir SO2 was found. Saw-tooth sign and VE50/VI50 greater than 1 on flow-volume curves were not related to the apnea index and desaturation index. These results indicate that the F-V curve is not useful for the diagnosis of OSA.

Humans↗
PubMed1989

[Study on frictional characteristics of KB horizontal brackets. A comparative study of kinetic frictional forces to be caused between various kinds of brackets and wires].

KB horizontal brackets were designed to tip no more than 6 degrees at the maximum. This tipping amount is based on the idea of reducing friction between a wire and brackets to allow the effective tooth movement of the Begg technique even with horizontally long brackets, and does not originate in the concept of carrying out tipping movement. Thereon, experimental measurements by use of Rheometer were conducted to review for comparison of the kinetic frictional forces caused between various wires and the following four types of brackets; KB horizontal brackets, Tip edge brackets, Straight edge brackets and Begg brackets. 1. In case of utilizing ribbon arch wires and rectangular wires, no significant difference was acknowledged among Tip edge, KB horizontal and Straight edge brackets. 2. There proved to be a reduction in the kinetic frictional forces by incorporating tip into the edgewise slots, when using smaller dimensions of the wires which call for the effective tooth movement, however, Begg brackets (in conjunction with Ordinary T-pins and/or Safety T-pins) showed the small value which is far less than that of the three kinds of brackets.

Orthodontic Appliances↗
PubMed1987

Temperature affects lung fluid and recoil during high tidal ventilation at low resting volume.

Effects of tidal volume (VT), end-expiratory pressure (EEP), and environmental temperature (Tenv) on elastic recoil force (Pel) and edema formation were examined in open-chest anesthetized rabbits. Sixty-two rabbits in four groups were ventilated for 3 h with VT of either 10 or 25 ml/kg body wt, EEP of 0 or 2 cmH2O, and Tenv of 18 or 35 degrees C. After ventilation, Pel at 80% of total lung capacity (P80) was significantly increased when ventilation was performed with the combination of large VT, 0 EEP, and low Tenv. This change was prevented by altering any one of the three conditions, e.g., small VT, positive EEP, or high Tenv. Similarly, elevation of minimum surface tension and reduction of surface activity index of lavages from excised lungs after ventilation were observed only when increased P80 was noted. Additionally, the increase of P80 was well correlated with increment of wet weight-to-dry weight ratio and degree of perivascular cuffing and alveolar edema formation of excised lungs. These results indicate that elevation of Pel after high tidal ventilation in open-chest animals in vivo was influenced by level of EEP and Tenv and that the degree of edema formation was closely related to the increase of Pel. The increased Pel is presumably primary and causes fluid accumulation.

Animals↗