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Biomedical subjects

K Asano

Publications and source records attributed to K Asano.

At least 217 records · Page 12Linked to original sources
PubMed1995

Cardiopulmonary function in bicycle racing over mountainous terrain at moderate altitude.

To examine cardiopulmonary function during exercise in a mountainous region at moderate altitude, we measured cardiac frequency, oxygen consumption (VO2), and percentage arterial hemoglobin oxygen saturation (%SaO2) before and after a bicycle race with a starting point at 638 m and finishing point at 1980 m. The time required to ascend an elevation of 10 m was prolonged with increasing altitude, and heart rate also increased with altitude. The %SaO2 at the starting point and at the finishing point differed significantly (P < 0.01). Faster cyclists exhibited higher %SaO2 and lower VO2, while slower cyclists exhibited a reduction in %SaO2 and an increase in VO2 immediately after the race. The %SaO2 recovery time was significantly correlated with the racing time (r = 0.54, P < 0.001). Therefore, the faster cyclists' oxygen debt upon completion of the race may be small and recovery of cardiopulmonary function may be fast, while the slower cyclists' oxygen debt may be large and recovery of cardiopulmonary function may be slow.

Adult↗
PubMed1995

Cardio-pulmonary function of cyclists competing on an ascending mountain course between altitudes of 1400 m and 2800 m.

Physiological changes were investigated in the cardio-respiratory function of competitors in a bicycle race which involved not a flat course but ascending a mountain, from 1400 m to 2800 m. Heart rate throughout the race, arterial oxygen saturation and pulmonary function before and after the race of well trained competitors were measured. The individual's maximal heart rate during the race was designated as HRmax for the calculations. (1) There were significant correlations between the age and the mean %HRmax during the race, between mean %HRmax and time, and between age and time (n = 15); the mean %HRmax had a 3.90 times greater effect on time than did age. (2) The individuals who performed best had lower values of oxygen saturation just after finishing the race (n = 51). (3) At 1 min after reaching the finishing line, oxygen saturation levels had recovered to the value of 20 min after finishing the race, whereas the heart rate was still in the process of recovery (n = 18). (4) Maximum expiratory flow at 50% vital capacity measured 30 min after reaching the finishing line was significantly higher than at the starting point. The intensity of the load on the cardiac system produced by completion of this course was estimated to be almost the same as that of a full marathon on a flat course. The time depended on both the youth of the cyclist and on his ability to maintain a high value of %HRmax during the race.

Adolescent↗
PubMed1995

Modulation of noradrenaline release through presynaptic alpha 2-adrenoceptors in congestive heart failure.

Stimulation of presynaptic alpha 2-adrenoceptors inhibits the release of noradrenaline from sympathetic nerve endings; however, the extent to which it operates in patients with congestive heart failure is still unknown. To investigate the degree of negative feedback to the release of noradrenaline via presynaptic alpha 2-adrenoceptors at sympathetic nerve endings, we measured plasma noradrenaline levels before and after the injection of phentolamine (i.e., plasma noradrenaline concentration at rest, plasma noradrenaline concentration after phentolamine injection [NAph], and the phentolamine-induced increase in plasma noradrenaline [delta NAph]). Plasma noradrenaline concentration at rest, NAph, and delta NAph increased in a stepwise manner from New York Heart Association class I to class III. A positive correlation was found between the plasma noradrenaline at rest and delta Naph (n = 123, r = 0.697, p < 0.001). These results suggest that the enhanced release of plasma noradrenaline is substantially buffered by the mechanism of noradrenaline release-inhibitory presynaptic alpha 2-adrenoceptors in patients with congestive heart failure, and this buffer serves to protect organs such as the heart from excess sympathetic stimulation.

Aged↗
PubMed1995

Age-related changes in ConA-induced cytokine production by splenocytes from senescence accelerated mice SAMP8.

In vitro production of interleukin-2 (IL-2), IL-4, IL-5 and interferon-gamma (IFN-gamma) by splenocytes stimulated with concanavalin A (ConA) was studied in senescence-accelerated mice (SAMP8; 2-14.5 months old) by employing AKR (2-9 months old), origin of SAM strain, as controls. Male and female SAMP8 mice showed an age-related decrease in IL-2 production from the age of 9 months and the phenomena were accompanied by an increase in IFN-gamma production with a large increment. AKR mice showed no decrease in IL-2 production even at 9 months of age, but there was an increase in IFN-gamma production showing levels lower than those in SAMP8 mice. Between IL-2 and IFN-gamma production during the ages of 2-9 months, there were negative correlations in male and female SAMP8 mice and a positive correlation in female AKR mice. The levels of IL-4 production were lower in SAMP8 than in AKR mice, although there was no difference in IL-5 production between SAMP8 and AKR mice. Male and female SAMP8 mice showed a positive correlation between IL-5 and IFN-gamma production. Only in SAMP8 females was an increase in IFN-gamma accompanied by an increase in IL-4. From these changes in the cytokine production profile was it concluded that SAMP8 mice were senescence-accelerated in immuno-responses in comparison with AKR mice and had some functional deficiency with respect to IL-4 production, a part of which resulted from over-production of IFN-gamma.

Aging↗
PubMed1995

Generation of effector T cells in Hymenolepis nana-infected, FK-506-treated BALB/c mice.

FK-506 administered into mice daily at a dose of 10.0 mg/kg (but not 1.0 and 5.0 mg/kg) caused suppression of protective immunity to Hymenolepis nana, when the agent was injected intraperitoneally during the induction phase of protective immunity. Daily administration of 10.0 mg/kg FK-506, during the course of larval development from challenge, also suppressed protective immunity. Inhibition of protective immunity was only observed in mice that received FK-506 for 6 days at a daily dose of 10.0 mg/kg and were challenged 24 h after the final FK-506 injection. FK-506 did not inhibit formation of effector cells that mediate delayed-type hypersensitivity (DTH) to H. nana egg antigen when the agent was administered intraperitoneally at a dose of 10.0 mg/kg/day for 6 days before cell preparation. However, FK-506 did inhibit DTH effector cell activation when cells prepared from infected, saline-injected mice were transferred into 10.0 mg/kg FK-506-treated recipient mice. These results strongly indicate that FK-506 cannot inhibit the generation of effector cells but will suppress their function in vivo.

Animals↗
PubMed1995

Diurnal variation of urinary leukotriene E4 and histamine excretion rates in normal subjects and patients with mild-to-moderate asthma.

BACKGROUND: Leukotriene E4 (LTE4) and histamine excreted into the urine reflect the in vivo synthesis and release of cysteinyl leukotrienes and histamine, respectively. We examined the diurnal variation of the excretion rate of these mediators over 4 consecutive days in normal subjects (n = 5) and patients with stable mild-to-moderate asthma (n = 8). METHODS: Sixteen consecutive 6-hour urine samples were collected over 4 days. Urinary LTE4 concentrations were determined by reverse-phase high-pressure liquid chromatography, followed by ELISA. Urinary histamine concentrations were measured by ELISA. The excretion rates of these compounds were normalized relative to urinary creatinine content. RESULTS: The mean urinary LTE4 excretion rate was 83.8 +/- 38.2 pg/mg creatinine (mean +/- SD) in normal subjects; in patients with asthma, the urinary LTE4 excretion rate (110.0 +/- 59.2 pg/mg creatinine) was significantly higher than that in normal subjects (p < 0.05). The urinary histamine excretion rate was not different between normal subjects (24.0 +/- 12.5 ng/mg creatinine) and patients with asthma (31.5 +/- 25.8 ng/mg creatinine). A robust and systematic within-day variation (p < 0.01), but no day-to-day variation, was observed in histamine excretion rate. Although the magnitude of variation in LTE4 excretion within a day was significantly greater in patients with asthma than in normal subjects (p < 0.05), we could not identify any specific diurnal variation pattern in either the normal or the asthma group. No significant correlation was observed between urinary LTE4 and histamine excretion rate within any subject. CONCLUSIONS: Patients with asthma excrete LTE4 in the urine at a greater rate than normal subjects. Although no systematic variation in urinary LTE4 excretion rates over the course of a day was observed in either normal subjects or patients with stable asthma, the presence of a systematic diurnal variation of urinary histamine excretion exists in both groups.

Adult↗
PubMed1995

A case of infantile febrile psoriasiform dermatitis.

An infant suffered from psoriasiform dermatitis complicated by severe constitutional symptoms. During his 12 months of hospitalization, the symptoms exacerbated periodically despite numerous therapeutic trials. Histologic findings revealed lichenoid psoriasiform dermatitis with striking eosinophilic necrosis of epidermal cells and satellite cell necrosis. Immunohistochemically, CD1+ Langerhans cells had almost disappeared, and CD8+ cytotoxic-suppressor T cells were predominant over CD4+ helper-inducer T cells in the epidermis. These findings in the skin biopsy specimens suggested some similarity to graft-versus-host disease but no known cause of that disorder was proved. Finally, methotrexate was effective. The patient became afebrile, and his skin lesions improved, leaving almost no scarring. This patient seems to have had specific clinical features that do not correspond with any of the known dermatitis. Clinical, histologic, and laboratory findings did not uncover any etiologic factors.

Dermatitis↗
PubMed1995

Superoxide dismutase derivative reduces oxidative damage in skeletal muscle of rats during exhaustive exercise.

A superoxide dismutase derivative (SM-SOD) that circulates and is bound to albumin with a half-life of 6 h was injected intraperitoneally into rats before exhaustive treadmill running to study its antioxidant scavenging capacity in the plasma and soleus and tibialis muscles. The exercise induced a marked increase in xanthine oxidase activity in plasma and an increase in thiobarbituric acid-reactive substances in the plasma as well as in the soleus and tibialis muscles of nonadministered rats immediately after the exercise. The immunoreactive content and activity of both SOD isoenzymes (Cu,Zn-SOD and Mn-SOD) of the nonadministered rats increased in the soleus and tibialis muscles immediately after running. SM-SOD treatment definitely attenuated the degree of the increase in thiobarbituric acid-reactive substances and xanthine oxidase in all samples examined immediately after exercise. Glutathione peroxidase activity significantly increased in the soleus muscle of nonadministered rats 1 day after running, whereas catalase activity remained unchanged throughout the experimental period. These results suggest that a single bout of exhaustive exercise induces oxidative stress in skeletal muscle of rats and that this oxidative stress can be attenuated by exogenous SM-SOD.

Animals↗
PubMed1995

Effect of azelastine on endotoxin-induced airway hyperresponsiveness in mice.

We examined the role of lipopolysaccharide (LPS) on the pulmonary inflammatory process in mice, including the release of interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha) by macrophages, and investigated the mechanism of action of azelastine (AZ) on the release of these two cytokines. Intratracheal instillation of 1.0 microgram/ml LPS into BALB/c mice caused a significant increase in both IL-1 beta and TNF-alpha in aqueous lung extracts. These changes were modified, under control conditions, by a single dose of 0.05 mg/kg of AZ administered 1 and 11 h after LPS infusion. Intratracheal instillation of LPS also caused a significant increase in bronchial hyperresponsiveness to methacholine (Mch). AZ significantly inhibited Mch responsiveness in LPS-infused mice compared with nontreated control mice. Our results suggested that intratracheal instillation of LPS induces the secretion of macrophage cytokines in the airways of mice, accounting, at least partly, for LPS-induced airway hyperresponsiveness. Our results also indicate that the attenuating effect of AZ on LPS-induced airway hyperresponsiveness could be explained by its inhibitory effect on macrophage cytokine production.

Administration, Inhalation↗
PubMed1995

Evaluation of lens transparency changes through photographed images during a 13-month observation period.

Since the development of the anterior eye segment analysis system, several new types of anterior eye segment biometry have been performed. The main aim of this study was to evaluate whether changes in cataractous progression or an increase in lens transparency loss are detectable during a relatively short period of 13 months by measuring the intrapupillary opaque shadow area through retroillumination images or by calculating the light scattering intensity at the deepest cortical layer of the lens through Scheimpflug slit images. Secondly, the relationship between maximally dilated pupil sizes and patients' ages and that between cases with and without diabetes were studied. Thirty-one eyes (49.2%) of sixty-three cataractous lenses showed more than 5% increase in the opaque shadow area. Forty-five eyes (60.0%) showed more than a 5% increase in light scattering intensity. 92.5% of diabetic eyes and 92.3% of nondiabetic eyes showed pupil sizes over 6.5 mm after an instillation of mydriatica. In our study the applied method guaranteed a high reproducibility; thus is might be possible to detect an increase in cataractous changes and lens transparancy in around 50% of examined subjects in a period as short a 1 year. For the evaluation of cataract progression through a retroillumination image, the recommendable pupil size is > or = 6.5 mm.

Aged↗
PubMed1995

Dexamethasone-induced changes in glucose transporter 4 in rat heart muscle, skeletal muscle and adipocytes.

To clarify the effect of glucocorticoid on glucose transporters (GLUT) in adipocytes and muscle, we examined the changes of GLUT4 in rat heart muscle, skeletal muscle and adipocytes during long-term administration of dexamethasone and the translocation of GLUT4. The levels of GLUT4 in the plasma membrane and the low-density microsome fraction were measured by Western blotting using anti-GLUT4 peptide antibody. The levels of GLUT4 in the heart and skeletal muscles of rat were unchanged by treatment of dexamethasone. In the adipocytes the level of GLUT4 in plasma membrane was changed, but it was decreased in the low-density microsome fraction. Although adipocytes are less involved in blood sugar regulation than skeletal muscle, this finding suggests that glucose metabolism in Cushing's syndrome is affected partly by a decrease of GLUT4 in the adipocytes.

5'-Nucleotidase↗
PubMed1995

Changes in lipid peroxidation and free radical scavengers in the brain of hyper- and hypothyroid aged rats.

To determine how lipid peroxides and free radical scavengers are changed in the brain of hyper- or hypothyroid rats, we examined the behavior of lipid peroxide and free radical scavengers in the cerebral cortex of aged (1.5 years old) rats that had been made hyper- or hypothyroid by the administration of thyroxine or methimazol for 4 weeks. Concentrations of catalase, Mn-superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) were increased in hyperthyroid rats compared with euthyroid rats. Concentrations of total SOD, Cu,Zn-SOD and GSH-PX were increased but that of Mn-SOD was decreased in hypothyroid animals. There were no differences among hyperthyroid, hypothyroid and euthyroid rats in the levels of coenzymes 9 or 10. The concentration of lipid peroxides, determined indirectly by the measurement of thiobarbituric acid reactants, was decreased in hyperthyroid rats but not in hypothyroid rats when compared with euthyroid animals. These findings suggest that free radicals and lipid peroxides are scavenged to compensate for the changes induced by hyper- or hypothyroidism.

Animals↗
PubMed1995

Adjustments of cardiac function during prolonged exercise relative to lactate threshold.

Alterations in cardiac function during prolonged submaximal exercise relative to lactate threshold (LT) were evaluated on 7 normal healthy males aged 30.3 +/- 5.7 years. Systolic time intervals were analyzed through simultaneous recordings of electrocardiogram, phonocardiogram, and impedance cardiogram at a paper speed of 50 mm/s. Determination of stroke volume (SV) was based upon the method described by Kubicek et al. ANOVA followed by the Scheffe post-hoc comparison revealed that SV and myocardial contractility indices (MSER and PEP/LVET) remained relatively unchanged throughout 40-min cycling exercise, although the changes in heart rate and oxygen uptake were statistically significant. In addition, systolic blood pressure remained almost unchanged during the exercise. These results may be interpreted as evidence of the "contractility reserve", i.e., the ability of maintaining heart muscle contractility during prolonged exercise at LT intensity.

Adult↗
PubMed1995

[Combination chemotherapy with POMB/ACE (cisplatin, vincristine, methotrexate, bleomycin, actinomycin D, cyclophosphamide, etoposide) in advanced non-seminomatous testicular tumor].

Four cases with non-seminomatous testicular tumor in stage III completed chemotherapy with POMB/ACE. Of these 4 cases, metastasis to retroperitoneal lymph nodes was found in all of them. In addition, metastasis to the lung was noted in 3, and to the left supraclavicular lymph nodes in one. After orchiectomy, 5 courses of POMB/ACE therapy were given to each of the 4 cases. Tumor marker returned to normal value in all of the cases after 3-4 courses of treatment, with disappearance of metastasis to the lung and supraclavicular lymph nodes. However, the response rate in metastasis to retroperitoneal lymph nodes was CR in one case, and PR in 3. Therefore, retroperitoneal lymph nodes were excised in all 3 cases. Histologically, 2 of the 3 were found to have necrotic tissues. The remaining one patient had teratoma. An additional 1-3 courses of POMB/ACE therapy were given to these 3 cases. These 4 cases are alive without recurrence 6 years and 4 months, 5 years and 8 months, 4 years and 9 months, and 2 years 9 months, respectively, after orchiectomy. Thus POMB/ACE therapy is considered to be a useful method in the treatment of advanced testicular tumor.

Adult↗
PubMed1995

[A case of recurrent constrictive pericarditis complicated with atrial septal defect].

A case of recurrent constrictive pericarditis complicated with atrial septal defect (ASD) was operated successfully at our institute. ASD was missed at the time of the first operation. The combination of ASD and constrictive pericarditis is rare and this case is the fifth reported one in Japan. Difficulty in diagnosis of ASD and operative procedure for recurrent constrictive pericarditis are described and discussed.

Heart Septal Defects, Atrial↗
PubMed1995

[A case report of Cabrol procedure with zero-porosity graft in a patient of annulo-aortic ectasia with severe aortic regurgitation].

A 63-year-old man was admitted to the hospital for the treatment of annulo-aortic ectasia with severe aortic regurgitation. The aortogram revealed dilatation of the aortic root and severe aortic regurgitation. LVEDVI was 207 ml/m2 but the patient was asymptomatic. Aortic root reconstruction was performed with Cabrol procedure using zero-porosity graft. There was no evidence of bleeding due to this graft and the percent dilatation of this graft was 33%. This zero-porosity graft of knitted Dacron coated with gelatin seems to offer some advantages to the operation. The patient is in stable health today, but perioperative occurrence of VPCs may have owed to diminished LV function caused by severe aortic regurgitation.

Aorta, Thoracic↗
PubMed1995

Effect of IPD-1151T (Suplatast Tosilate) on airway hyperresponsiveness in mice.

We investigated the effect of IPD-1151T (Suplatast Tosilate, (+/-)-[2-[4-(3-ethoxy-2-hydroxypropoxy) phenyl-carbamoyl]-ethyl] dimethylsulfonium p-toluenesulfonate) against allergic bronchoconstriction induced by allergen and methacholine (MCh).BALB/c mice were sensitized by intraperitoneal injection of 0.5 microgram of keyhold limpet hemocyanin mixed with Al(OH)3. IPD-1151T was administered orally once a day for 5 or 14 days in doses of 10, 30 or 100 mg/kg body weight. Bronchoconstriction was measured 24 hrs after the final drug administration. IPD-1151T inhibited both antigen-mediated allergic bronchoconstriction and induction of bronchial hyperresponsiveness after sensitization or allergen challenge in actively sensitized mice. The degree of inhibition was proportional to the dose and frequency of oral administration of the agent.

Administration, Oral↗