Search PubMed⌕ Search

Biomedical subjects

M Ichioka

Publications and source records attributed to M Ichioka.

At least 19 recordsLinked to original sources
PubMed1992

Changes of circulating atrial natriuretic peptide and antidiuretic hormone in obstructive sleep apnea syndrome.

Patients with obstructive sleep apnea (OSA) syndrome are known to exhibit nocturnal natriuresis/diuresis. We studied plasma and urinary levels of atrial natriuretic peptide (ANP), a potent natriuretic hormone released from the heart, and plasma antidiuretic hormone (ADH) levels in patients with OSA during awake and sleeping periods, to compare with those of normal subjects. Seven patients with OSA and 6 normal subjects were studied. Arterial blood samples were drawn during the awake and the sleeping period, while in patients with OSA, blood samples were obtained during the apneic period. Urine samples were collected over two 12-hour periods (9 a.m.-9 p.m. and 9 p.m.-9 a.m.) In patients with OSA, plasma ANP as well as urinary ANP excretion increased during the apneic period compared with the awake period. There was a significant negative correlation between plasma levels of ANP and ADH in patients with OSA. On the other hand, normal subjects had no apparent differences in plasma and urinary ANP levels between the two periods. It is suggested that nocturnal increase in ANP and decrease in ADH are responsible for the nocturnal diuresis and natriuresis associated with OSA.

Adult↗
PubMed1992

A new variant of alpha-1-antitrypsin deficiency (Siiyama) associated with pulmonary emphysema.

A 38-year-old male with pulmonary emphysema due to severely reduced serum alpha-1-antitrypsin (AAT) level (14.5 mg/dl) was found to have an inherited new AAT deficient variant Siiyama. Chest roentgenogram and CT scanning revealed advanced emphysema, and severe obstructive ventilatory impairment was observed. During the 4-year follow-up period, the annual rate of decline of FEV 1.0 showed approximately 10-fold greater than the normal decline in FEV 1.0 (-380 ml/yr). Treatment with tamoxifen in order to raise the serum AAT level only resulted in an insufficient increase. Augmentation therapy of human AAT should be considered in the future.

Adult↗
PubMed1992

[Serum 7S collagen levels in diffuse interstitial lung diseases--an index of the destruction of alveolar structure].

To examine whether alteration of 7S collagen in the alveolar basement membrane is related to the condition and prognosis of diffuse interstitial lung diseases (idiopathic interstitial pneumonia: IIP, collagen vascular diseases, sarcoidosis, and hypersensitivity pneumonitis), we measured serum 7S collagen levels in 123 patients with diffuse interstitial lung disease and other lung diseases. Patients with diffuse lung diseases (diffuse interstitial lung disease, pulmonary emphysema, and diffuse panbronchiolitis: DPB) showed significantly higher serum levels of 7S collagen than healthy normal controls. Serum 7S collagen levels in IIP and collagen vascular diseases were significantly higher than those in pulmonary emphysema and DPB. In cases of IIP, serum 7S collagen levels in the active stage were significantly higher than those in the inactive stage. Furthermore, the prognosis of patients with higher serum 7S collagen levels was significantly poorer than those of patients with lower serum 7S collagen levels. In infectious pulmonary diseases, serum 7S collagen levels of patients with adult respiratory distress syndrome (ARDS) were significantly higher than those of patients without ARDS. Autopsy specimens obtained from patients with positive serum 7S collagen showed diffuse alveolar damage and/or diffuse pulmonary hemorrhage in the alveolar areas. Immunohistochemical staining for 7S collagen showed disruption and/or loss of the alveolar basement membrane. The authors conclude that serum level of 7S collagen is useful for estimating the activity of diffuse interstitial lung diseases as an index of the destruction of alveolar structure.

Basement Membrane↗
PubMed1991

Ratings of perceived exertion in chronic obstructive pulmonary disease--a possible indicator for exercise training in patients with this disease.

The purpose of this study was to evaluate the usefulness of ratings of perceived exertion (RPE) as an indicator of exercise intensity in patients with chronic obstructive pulmonary disease (COPD). The subjects were ten male patients with COPD, whose mean forced expiratory volume in 1 s was 1.09 1, SD 0.41, and ten healthy middle-aged men. Ramp incremental exercise on a cycle-ergometer was performed and RPE was determined by the Borg 15-point scale. The absolute oxygen uptake at each RPE was significantly greater in the healthy subjects than in the patients with COPD. However, oxygen uptake calculated as a percentage of maximal at any RPE did not differ significantly between the two groups. Arterial blood lactate concentration at points 15 to 19 on the RPE scale was increased in healthy subjects (P less than 0.05-P less than 0.001), while the dyspnoea index at points 11 to 19 on the RPE scale was higher in patients with COPD (P less than 0.05-P less than 0.001). The main complaints on stopping exercise were dyspnoea in the patients with COPD and fatigue in the healthy subjects. Although the nature of RPE may have been different in the two groups, RPE could be a possible indicator of exercise intensity when physicians prescribe exercise to patients with COPD.

Adult↗
PubMed1991

Ventilatory response and arterial potassium concentration during incremental exercise in patients with chronic airways obstruction.

The relationship of ventilation response (VE) to arterial potassium concentration (K+) during ramp incremental exercise was assessed in nine patients with chronic obstructive pulmonary disease (COPD), and in 10 healthy subjects. For COPD patients the maximum oxygen uptake (VOmax) was 19.6 +/- 3.8 ml kg-1 min-1 (+/- SD), and percentage of forced expired volume at 1 s (% FEV1) was 47.8 +/- 10.4%. In healthy subjects, VO2max was 44.4 +/- 7.0 ml kg-1 min-1 and FEV1 was 89.7 +/- 7.4%. Breath-by-breath determinations for VE, oxygen uptake (VO2) and carbon dioxide output (VCO2), as well as determinations for K+, partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), pH and lactate in arterial blood were performed during a workout on an exercise bicycle at a ramp function work rate of 20 W min-1, preceded by a 40 min warm-up period. The major findings in the present study are: (1) that there is a linear relation between ventilation and arterial K+ concentration during ramp exercise in both healthy subjects and COPD patients; (2) that the slope of the VE-K+ relationship is significantly lower in COPD patients (16.2 +/- 7.3 l min-1 mM-1) than in normal subjects (37.4 +/- 6.9 l min-1 mM-1, P less than 0.01); and, (3) that the slope of the VE-K+ relationship is significantly related to the ability to ventilate during maximal exercise in both healthy subjects and COPD patients (P less than 0.05). It is thought that the significantly reduced slope of the VE-K+ relationship in the COPD patients could be interpreted as a reduced sensitivity to the stimulus and/or as a mechanical impairment of the ventilation.

Adolescent↗
PubMed1991

[Diffuse panbronchiolitis in two brothers with different clinical courses].

Diffuse panbronchiolitis in two brothers is reported. The elder brother aged 46, was admitted in May 1983 due to severe dyspnea and productive cough, which had gradually worsened over several years. He had severe hypoxemia and hypercapnia. He died at age 47 of respiratory failure due to pseudomonas infection despite antibiotic therapy. The younger brother, at age 41, was admitted in March 1983 due to fever, productive cough, and abnormal shadows on chest X-ray films. He showed mild hypoxemia and his symptoms improved with antibiotic treatment. Since then he has been followed as an outpatient for over 7 years while taking 400 mg of Erythromycin per day, and he has had no exacerbation. These two cases had different clinical courses despite the facts that both had similar conditions of chronic sinusitis and appeared to be exposed to no special environmental or occupational hazards. These facts suggest that not only intrinsic factors, such as defenselessness of airways, but extrinsic factors such as viral, mycoplasmal, or bacterial infection may act together on the mechanisms of the onset and progression of diffuse panbronchiolitis.

Adult↗
PubMed1991

[Interleukin-2 (IL-2) in active pulmonary tuberculosis].

To clarify the precise of cellular immunity mechanism in pulmonary tuberculosis, we investigated the amount of IL-2 in patients with untreated active pulmonary tuberculosis. When serum adenosine deaminase (ADA) activity was examined using enzyme assay, an abnormally high level was observed in all patients (29.0 + 11.6 IU/ml, mean + SD; 4.5-17.8, normal range). Likewise, the level of serum-soluble interleukin-2 receptor (IL-2R) measured by ELISA showed abnormal high level in all patients (844.3 + 584.8 IU/ml; 80-300, normal range). When stimulated using PHA, the peripheral lymphocyte's ability to produce IL-2 revealed no difference between control subjects and patients. It was, however, noted that the lymphocytes of the patients significantly suppressed IL-2 responsiveness when compared to the control subjects (P less than 0.05). The serum IL-2 concentration measured using RIA could not be detected in any of the patients as was the same for control subject. All of the above mentioned results suggest that T-cell activation which caused increment in serum ADA activity and soluble IL-2R occurred in active pulmonary tuberculosis. The suppressed IL-2 responsiveness in the peripheral lymphocytes of patients proposes the possibility of soluble IL-2R reduction by the negative feedback mechanism in IL-2-sensitive lymphocytes.

Adenosine Deaminase↗
PubMed1990

Relationship between ventilation and arterial potassium concentration during incremental exercise and recovery.

The purpose of this study was to compare the relationship of ventilation (VE) with pH, arterial concentrations of potassium [( K+]a), bicarbonate [( HCO3-]a), lactate [( la]a), and acid-base parameters which would affect hyperpnoea during exercise and recovery. To assess this relationship, ten healthy male subjects exercised with intensity increasing as a ramp function of 20 W.min-1 until voluntary exhaustion and they were then allowed a 5-min recovery period. Breath-by-breath gas exchange data, [HCO3-]a, pH, [la]a, [K+]a and blood gases were determined during both exercise and recovery. Using a linear regression method, the VE/[K+]a relationship was analysed during both exercise and recovery. Several interesting results were obtained: a significant relationship between [K+]a and VE was observed during recovery as well as during exercise; the VE at any given values of [K+]a was significantly higher during recovery than during exercise and out of those factors affecting exercise hyperpnoea, only [K+]a had a similar time-course to VE during recovery. Changes in [K+]a during recovery were shown to occur significantly faster than VE with an [K+]a time constant of 70.0 s, SD 16.2 as opposed to 105.5 s, SD 10.0 for VE (P less than 0.01). These results provided further evidence that [K+]a might play an important role as a substance which can stimulate exercise hyperpnoea as has been suggested by other workers. The present study also showed that during recovery [K+]a contributed significantly to the control of VE.

Adult↗
PubMed1990

Specificity of physiological adaptation to endurance training in distance runners and competitive walkers.

The present study was designed to evaluate the specificity of physiological adaptation to extra endurance training in five female competitive walkers and six female distance runners. The mean velocity (v) during training, corresponding to 4 mM blood lactate [onset of blood lactate accumulation (OBLA)] during treadmill incremental exercise (training v was 2.86 m.s-1, SD 0.21 in walkers and 4.02 m.s-1, SD 0.11 in runners) was added to their normal training programme and was performed for 20 min, 6 days a week for 8 weeks, and was called extra training. An additional six female distance runners performed only their normal training programme every day for about 120 min at an exercise intensity equivalent to their lactate threshold (LT) (i.e. a running v of about 3.33 m.s-1). After the extra training, there were statistically significant increases in blood lactate variables (i.e. oxygen uptake (VO2) at LT, v at LT, VO2 at OBLA, v at OBLA; P less than 0.05), and running v for 3,000 m (P less than 0.01) in the running training group. In the walking training group, there were significant increases in blood lactate variables (i.e., v at LT, v at OBLA; P less than 0.05), and walking economy. In contrast, there were no significant changes in lactate variables, running v and economy in the group of runners which carried out only the normal training programme. It is suggested that the changes in blood lactate variables such as LT and OBLA played a role in improving v of both the distance runners and the competitive walkers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1990

Significance of the contribution of aerobic and anaerobic components to several distance running performances in female athletes.

To assess the most important determinant for successful distance running (800 m, 1500 m and 3000 m events) in female athletes, measurements of several anaerobic indices were made (peak power, mean power) using the Wingate anaerobic test (WAnT), and aerobic indices such as oxygen uptake (VO2) or running velocity (v) at lactate threshold (LT), VO2 or v at onset of blood lactate accumulation (OBLA), running economy (RE), and maximal oxygen uptake were determined using the incremental treadmill test. The RE was represented by a VO2 value measured at 240 m.min-1 of a standard treadmill velocity. A stepwise multiple regression analysis (SAS stepwise procedure) combined the best features of forward inclusion and backward elimination to determine the most important factors in predicting the performance of running these distances as dependent variables. The stepwise procedure showed that the blood lactate variables such as LT and/or OBLA are highly correlated with, and contributed to predicting performance running 800 m-3000 m, whereas the anaerobic component was related only to running 800 m. In conclusion, blood lactate variables account for a large part of the variation in distance running performance in female as in male runners. The component of the anaerobic system which can be measured by the WAnT was shown to contribute to performance in running 800 m, but not in longer distances.

Adult↗
PubMed1989

Effect of hypoxia on arterial and venous blood levels of oxygen, carbon dioxide, hydrogen ions and lactate during incremental forearm exercise.

The purpose of the present study was to investigate whether, in humans, hypoxia results in an elevated lactate production from exercising skeletal muscle. Under conditions of both hypoxia [inspired oxygen fraction (F1O2): 11.10%] and normoxia (F1O2: 20.94%), incremental exercise of a forearm was performed. The exercise intensity was increased every minute by 1.6 kg.m.min-1 until exhaustion. During the incremental exercise the partial pressure of oxygen (PO2) and carbon dioxide (PCO2), oxygen saturation (SO2), pH and lactate concentration [HLa] of five subjects, were measured repeatedly in blood from the brachial artery and deep veins from muscles in the forearm of both the active and inactive sides. The hypoxia (arterial SO2 approximately 70%) resulted in (1) the difference in [HLa] in venous blood from active muscle (values during exercise-resting value) often being more than twice that for normoxia, (2) a significantly greater difference in venous-arterial (v-a) [HLa] for the exercising muscle compared to normoxia, and (3) a difference in v-a [HLa] for non-exercising muscle that was slightly negative during normoxia and more so with hypoxia. These studies suggest that lower O2 availability to the exercising muscle results in increased lactate production.

Adult↗
PubMed1989

Arterial blood gases, acid-base balance, and lactate and gas exchange variables during hypoxic exercise.

To determine the effect of hypoxia on lactate threshold (LT), onset of blood lactate accumulation (OBLA), and gas exchange threshold (GET), the lactate level together with VO2, VCO2, VE, and acid-base status in arterial blood from 12 female distance runners performing a progressive incremental treadmill test under the condition of hypoxic gas inhalation (HC: FIO2 is 16.0% in N2) compared with normoxic conditions (NC: FIO2 is 20.9%; i.e., air) were examined. During exercise, HC shifted LT, GET, and OBLA to a lower VO2 by 12.5%, 12.9%, and 9.3%, respectively. The GET during hypoxic exercise was well correlated with LT (GET = 0.973LT + 0.04; expressed in VO2 l.min-1). The close reciprocal changes in arterial blood lactate and bicarbonate (HCO3-) were observed during hypoxic as well as normoxic exercise. These findings provide evidence for the cause and effect relationship between LT and GET, even in hypoxic exercise. During submaximal exercise below the LT, PaCO2 and HCO3- slightly increased both in NC and HC with pH remaining unchanged. However, during exercise above the LT, the PaCO2, HCO3-, and pH all decreased with pH decreasing more markedly during hypoxia. In conclusion, this study demonstrated a clear increase in arterial lactate during hypoxic exercise above the LT. Both the LT and GET are shifted to a lower work rate by hypoxia in the same manner with the correlation between them remaining high, supporting the cause and effect relationship of these two parameters.

Acid-Base Equilibrium↗
PubMed1987

Blood lactate parameters related to aerobic capacity and endurance performance.

The relationships among four descriptors of lactate increase: lactate threshold (LT) (the VO2 at which blood lactate concentration begins to increase above the resting level during an incremental exercise test), LT1 (the VO2 at which blood lactate increases 1 mM above the resting level), LT2 (the VO2 at which blood lactate concentration reaches a fixed value of 2 mM), onset of blood lactate accumulation (OBLA; the VO2 at which blood lactate reaches a concentration of 4 mM), were compared with aerobic capacity (VO2max) and 12 min running performance in 19 untrained female students. The VO2 (+/- SD) of LT, LT1, LT2, OBLA, and VO2max were 14.5 +/- 3.7 ml X kg-1 X min-1, 22.5 +/- 4.3 ml X kg-1 X min-1, 22.2 +/- 4.5 ml X kg-1 X min-1, 30.3 +/- 5.2 ml X kg-1 X min-1 and 36.0 +/- 5.1 ml X kg-1 X min-1, respectively. The mean (+/- SD) distance covered in the 12 min running was 2356 +/- 160 m. The results were as follows: 1) the lactate parameters (i.e. LT, LT1, LT2, and OBLA) were highly correlated with each other. 2) all the lactate parameters were related to VO2max and endurance running performance with a high correlation coefficient. Of the four descriptors of lactate change with exercise, LT correlated best with VO2max and endurance running performance compared to LT1, LT2 and OBLA. It is concluded that lactate threshold is the best index for aerobic capacity and endurance running performance.

Adult↗