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Biomedical subjects

M Okazaki

Publications and source records attributed to M Okazaki.

At least 307 records · Page 17Linked to original sources
PubMed1993

Mode of action of exo- and endo-type cellulases from Irpex lacteus in the hydrolysis of cellulose with different crystallinities.

The mode of action of two highly purified cellulases of exo- and endo-types from Irpex lacteus was investigated by using pure cellulosic substrates with different crystallinities derived from cellulose I. Exo-type cellulase saccharified all celluloses more effectively than endo-type enzyme, and the saccharification activities of both cellulases similarly increased with decreasing crystallinity of cellulose. The DP-lowering activity of exo-type cellulase remained similar for celluloses with higher crystallinity, while this cellulase showed a degradation mode resembling that of the endo-type enzyme for the substrates with lower crystallinity. Compared with exo-type cellulase, endo-type cellulase remarkably decreased the DP of cellulose with higher crystallinity, while this activity was abated for cellulose with lower crystallinity. Thus, the effects of both cellulases became similar in the degradation of amorphous substrates such as H3PO4-treated cellulose. Endo-type cellulase produced several kinds of cellooligosaccharide from all kinds of cellulose used, while the product of the exo-type enzyme was only cellobiose from crystalline cellulose such as cotton and cotton linter even after a 12-h incubation period. The results indicate that each cellulase shows a typical mode of action (exo or endo) for crystalline cellulose, but that their characteristic modes of attack may change with decreasing crystallinity of cellulose.

Cellulase↗
PubMed1993

Electron microscopic observation of cotton cellulose degradation by exo- and endo-type cellulases from Irpex lacteus.

The interaction of two highly purified cellulases, exo- and endo-type cellulases from Irpex lacteus, with pure cotton and amorphous cellulose was investigated by electron microscopy. The morphological observations indicated that exo- and endo-type cellulases are both strongly adsorbed on the internal microfibril of cotton fiber before enzymatic hydrolysis, and then initiate their action toward the internal cellulose microfibrils with retention of the original shape. The two cellulases, however, caused considerably different morphological changes in cotton cellulose, and each cellulase seems to degrade native cellulose with a distinct mode of action. In the hydrolysis of cotton with exo-type cellulase, deep transverse cracks were produced and they extended from the fiber surface to the lumen structure located inside the fibers. In contrast, it was found that there were no deep cracks on fibers treated with endo-type cellulase, but severe internal erosion and cavitation occurred along fibril or microfibril layers inside the fibers. Thus, the degradation of cotton by exo- and endo-type cellulases yielded quite different morphological patterns, while little difference was found for regenerated celluloses. The mode of enzymatic hydrolysis of cellulose shown by cellulases with different degrees of randomness (exo and endo types) appears to be markedly affected by the fine structure of cellulose fibers.

Antibody Specificity↗
PubMed1993

Well-developed infant with hypoxic-ischemic encephalopathy associated with EEG burst suppression and subcortical leukohypodensity on CT scan.

In the prediction of neurological sequelae after hypoxic-ischemic encephalopathy (HIE) in the newborn, the electroencephalogram (EEG) burst suppression pattern (BS) and subcortical leukomalacia can mean grave neurodevelopmental problems will develop. This study presents an infant with HIE associated with BS and subcortical leukohypodensity (SLH) on computed tomography scan. At first her neurodevelopmental outcome was considered poor, but unexpectedly she showed good development in 32 months follow-up. The findings of BS and SLH do not always result in a poor neurodevelopmental outcome, if the subsequent clinical state and EEG return to normal at an early stage.

Brain Ischemia↗
PubMed1993

Changes in the proportions of bronchoalveolar lymphocytes, neutrophils and basophilic cells and the release of histamine and leukotrienes from bronchoalveolar cells in patients with steroid-dependent intractable asthma.

The proportion of inflammatory cells in bronchoalveolar lavage (BAL) fluid and the release of chemical mediators from BAL and peripheral blood cells were examined in 40 patients with steroid-dependent intractable asthma (SDIA) to clarify the effects of a long-term glucocorticoid regimen on these cells. The proportion of BAL lymphocytes was significantly reduced (p < 0.01) and the proportion of BAL neutrophils was significantly increased (p < 0.01) in SDIA patients compared with non-SDIA patients. The proportion of basophilic cells (mast cells and basophils) in BAL fluid was significantly lower in SDIA patients compared to non-SDIA patients (p < 0.02). The values of six ventilatory parameters were significantly lower in SDIA patients with a high proportion of BAL neutrophils (more than 10%) compared with the values in non-SDIA patients. The release of histamine and leukotriene C4 (LTC4) from the BAL cells of patients with atopic asthma was significantly reduced in SDIA patients compared with non-SDIA patients (p < 0.05). These results show that the changes in the proportion of BAL cells are observed in patients with SDIA, and these changes are related to suppressed ventilatory function and a reduction in the release of histamine and LTC4 from BAL cells.

Adult↗
PubMed1993

Crystallographic morphology of heterogeneous fluoridated carbonate apatites.

Carbonate-containing fluoridated apatites were synthesized with two different modes of fluoride incorporation: by supplying F-free solution initially, followed by a F-containing solution; and with the order of supply of these solutions reversed. Both of these heterogeneously synthesized fluoridated CO3 apatites showed typical apatitic x-ray diffraction patterns; and both had similar total fluoride contents (0.87 +/- 0.07 and 0.94 +/- 0.03 mmol/g, respectively), i.e., half of the maximum fluoride content of fluorapatite. However, they differed considerably in their crystallographic properties. The 300 reflection peaks of both apatites were split, and their patterns were slightly different. In the former, SEM observation revealed capsule-like crystals with a rounded hexagonal shape. However, the latter had many small crystals, similar to those of homogeneous CO3 apatite, adhering to the larger hexagonal crystals, which were also similar to homogeneous fluorCO3 apatite. Wavelength-dispersive spectroscopy attached to the SEM showed a higher fluoride intensity in the former spectrum than the latter. These results suggest that two different types of heterogeneous fluoridated CO3 apatites were formed, CO3 apatite covered with fluorCO3 apatite, and fluorCO3 apatite covered with CO3 apatite. The simple two-step supply system used in this study is helpful for the study of complicated heterogeneous formation of apatites.

Apatites↗
PubMed1993

Streptozocin-diabetes modifies acetylcholine release from mouse phrenic nerve terminal and presynaptic sensitivity to succinylcholine.

Acetylcholine (ACh) release from the motor nerve terminal in the streptozocin-induced diabetic state was studied in mouse phrenic nerve-diaphragm muscle preparations. Electrically evoked release of 3H-ACh from the preparation preloaded with 3H-choline was measured during two consecutive periods of stimulation (S1 and S2). In diabetic mice, the amount of 3H-ACh release during S2 was decreased, and the evoked ACh release declined more steeply with successive stimulation periods than in normal ddY mice. The decrease in release was restored when the presynaptic autoreceptors were stimulated by accumulating ACh under the irreversible inhibition of junctional cholinesterase by methanesulfonyl fluoride. This effect was abolished by the administration of (+)-tubocurarine (5 microM). In diabetic mice, the biphasic (acceleration and suppression) effect by succinylcholine on evoked ACh release was caused at 3- to 10-fold lower concentrations than in normal mice. The degree of enhancement of resting 3H-overflow by succinylcholine (10 and 30 microM) was greater in the diabetic state. These results indicated that in the diabetic state, the decrease in evoked ACh release interferes with its presynaptic action on inducing further release (positive feedback modulation) via the presynaptic nicotinic ACh receptor (n-AChR). The presynaptic hypersensitivity to succinylcholine may be due to the augmentation of presynaptic n-AChR sensitivity caused by the reduction of evoked ACh release in the diabetic state.

Acetylcholine↗
PubMed1993

Cell-mediated immunity in bronchial asthma evaluated by purified protein derivative- and Candida albicans-skin reaction.

Cell-mediated immunity was examined in 45 patients with bronchial asthma by observing the delayed cutaneous reaction to purified protein derivative (PPD) and Candida albicans (C. albicans). The delayed skin reaction to PPD showed a decrease with age starting between 50 and 59 years old. The delayed reaction to PPD decreased more prominently with aging, being significantly depressed in the patients aged over 70 years than in those aged between 30 and 49 years (induration, p < 0.02; flare, p < 0.01). The C. albicans-induced skin reaction was significantly lower in the patients aged over 70 years than in those between 60 and 69 years old (induration, p < 0.01; flare, p < 0.05). The delayed skin reaction to PPD and C. albicans was significantly depressed in the patients with a serum IgE level over 1001 IU/ml. Delayed skin reaction to PPD and C. albicans was more depressed with aging and an elevated serum IgE, and the age (50-59 years) at the initiation of depression in the PPD-induced delayed skin reaction was younger than that (over 70 years) in the C. albicans-induced reaction.

Adult↗
PubMed1993

Chemical mediator and cellular reaction in the bronchoalveolar lavage fluid of patients with steroid-dependent intractable asthma (SDIA).

The effects of long-term glucocorticoid therapy on chemical mediator and cellular reaction in the airways were examined in 69 patients with bronchial asthma. The histamine release induced by Ca ionophore A23187 from cells in the bronchoalveolar lavage (BAL) fluid of atopic asthmatics was significantly lower in the subgroup with steroid-dependent intractable asthma (SDIA) than in non-SDIA patients (p < 0.05). In contrast, histamine release in nonatopic SDIA patients did not differ from nonatopic non-SDIA patients. The release of leukotriene C4 (LTC4) was significantly lower in atopic patients with SDIA (p < 0.02). However, there was no significant difference in LTC4 release between nonatopic patients with SDIA and without SDIA. The proportion of BAL lymphocytes was significantly lower in atopic patients with SDIA than in those without it (p < 0.05), although there was no significant difference between the nonatopic patients with and without SDIA. These results show that glucocorticoids affect humoral and cellular events in the airways of atopic asthmatics more than in those of nonatopic asthmatics.

Adult↗
PubMed1993

A new modified classification of bronchial asthma based on clinical symptoms.

The clinical features of four asthma types, Ia-1 (bronchospasm with 0-49 ml/day of expectoration), Ia-2 (with 50-99 ml/day), Ib (over 100 ml/day), and II (bronchiolar obstruction), as classified by the clinical symptoms, were compared in 119 patients with bronchial asthma. The age of onset characteristic symptoms of each asthma type was in the 20's in types Ia-1 and Ia-2, in the 30's in type Ib, and in the 40's in type II patients. A significant increase in the number of neutrophils in bronchoalveolar lavage (BAL) fluid was found in type II patients. The proportion of BAL eosinophils was significantly higher in types Ia-2 and Ib asthma patients compared with that in type Ia-1 patients. The BAL eosinophil count was significantly higher in type Ib than in type Ia-2 patients. The FEV1.0% and %V25 values were significantly lower in patients with type II asthma than in the patients with the other asthma types. Steroid-dependent intractable asthma (SDIA) was more often observed in patients with type Ib or type II asthma.

Adolescent↗
PubMed1993

Mucus hypersecretion and eosinophils in bronchoalveolar lavage fluid in adult patients with bronchial asthma.

Mucus hypersecretion was clinically analyzed in 46 adult patients with bronchial asthma, including 22 with steroid-dependent intractable asthma (SDIA). A large amount of expectoration, over 50 ml/day, was observed in 16 of these patients (34.8%), of whom 12 (75.0%) had SDIA and 13 (81.3%) were women. The mean amount of expectoration increased with increasing patient age, although no significant difference was found among the six age groups. A large amount of expectoration (over 50 ml/day) was clearly correlated with an increased proportion of eosinophils in bronchoalveolar lavage (BAL) fluid. The proportion of BAL eosinophils was significantly higher in patients with expectoration between 50 and 99 ml/day (p < 0.05) and over 100 ml/day (p < 0.01) than in patients whose expectoration volume was between 30 and 49 ml/day. These results show that in bronchial asthma patients, mucus hypersecretion is more often observed clinically in those with SDIA and in women, and that this hypersecretion is closely correlated with BAL eosinophilia, which is a feature of the pathophysiological changes that occur in the airways of these patients.

Adult↗
PubMed1993

Effects of long-term glucocorticoid therapy on bronchoalveolar cells in adult patients with bronchial asthma.

The effects of long-term glucocorticoid therapy on airway inflammation were examined in 84 asthma patients. The proportion of lymphocytes in bronchoalveolar lavage (BAL) fluid was significantly decreased in patients with steroid-dependent intractable asthma (SDIA) compared to results in non-SDIA patients, while BAL neutrophils were significantly increased in SDIA patients compared to results in non-SDIA patients. Regarding age, in patients under the age of 69 (except those between 30 and 39), BAL lymphocyte number was significantly decreased in SDIA compared with non-SDIA subjects, and in patients between 50 and 69, BAL neutrophils were significantly increased in SDIA compared with non-SDIA subjects. The number of BAL lymphocytes was significantly lower in patients with serum cortisol levels of less than 5.0 micrograms/dl than in those with levels of more than 5.1 micrograms/dl. BAL lymphocyte number was also significantly lower in patients who had received glucocorticoid therapy for more than 6 years than in those who had received such therapy for 2 years. These results show that long-term glucocorticoid therapy decreases the number of lymphocytes and increases neutrophil numbers in the airways.

Adult↗
PubMed1993

[Characteristics of clinical asthma types in elderly patients with bronchial asthma].

Asthma was classified into four types, Ia-1 (bronchospasm with 0-49 ml/day of expectoration), Ia-2 (with 5-99 ml/day), Ib (over 100 ml/day) and II (bronchiolar obstruction), according to clinical symptoms. Characteristics of airway responses in each clinical asthma type were compared between 25 elderly (mean age, 65.2 years) and 30 younger subjects (mean age, 44.9 years) with bronchial asthma, by observing ventilatory function and cellular composition in bronchoalveolar lavage (BAL) fluid. 1. In patients with types 1a-2 and Ib, the %V25 value was significantly lower in the elderly subjects than in the younger subjects. 2. Comparing the values of ventilatory parameters of type Ia-1 cases with other asthma types, %V25 value was lower in other asthma types than in type Ia-1 in the elderly. All ventilatory parameters examined were generally lower in type II cases than in other asthma types in the elderly, but this difference was not significant. In contract, in the younger subjects, the values of %MMF, %V50 and %V25 were significantly lower in type II cases than in other asthma types. 3. The proportion of neutrophils in bronchoalveolar lavage (BAL) fluid was higher in the younger patients with type II than in the elderly patients with the same type, although there was no significant difference between older and younger subjects. The proportion of BAL eosinophils in patients with type Ib was significantly higher in younger subjects than in elderly subjects. These results indicate that airway responses which are characteristic of each asthma type are stronger in younger patients than in elderly patients.

Aged↗
PubMed1993

[Release of histamine and leukotrienes C4 and B4, and bronchial hyperresponsiveness in elderly patients with asthma].

Thirty patients with atopic asthma in whose asthma IgE-mediated allergic reaction participates, were selected for this study. They were divided into three age groups: elderly patients aged 60 and over, middle-aged patients between the ages of 40 and 59, and young patients between 20 and 39, to clarify the effects of aging on the mechanism of onset of asthma. In the cellular composition of bronchoalveolar lavage (BAL) fluid, the proportion of BAL lymphocytes was increased in elderly patients, and the proportion of BAL eosinophils was increased in young patients, although there was no statistically significant difference between the proportions of these cells in the three age groups. The proportion of BAL basophilic cells (basophils and mast cells) was significantly lower in elderly patients than in young patients (p < 0.05). The release of histamine from BAL cells was significantly lower in elderly patients than in middle-aged patients (p < 0.05) and young patients (p < 0.02). There was, however, no significant difference between the release of leukotrienes C4 (LTC4) and B4 (LTB4) in the three age groups. The release of histamine, LTC4 and LTB4 from peripheral leucocytes was not significantly different between the three age groups. Finally, Bronchial reactivity to methacholine showed a tendency to decrease with aging.

Adult↗
PubMed1993

Castability and surface hardness of titanium cast plates obtained from experimental phosphate-bonded silica investment molds.

The effect of 12 different experimental compositions of phosphate-bonded SiO2 investments was examined on cast pure titanium. The mold temperature was 600 degrees C and the casting was conducted with an argon-arc melting and pressure casting machine. Castability was evaluated by the volume of casting porosity, which was calculated from the volume of wax pattern (15 mm x 15 mm x 1.5 mm), the weight of cast plate and the specific density of pure titanium. The existence of inner casting porosities was confirmed by an X-ray non-destructive inspection instrument. Cast plates made in molds with cristobalite had significantly lower castability and higher surface hardness than those in molds with quartz as a refractory material. Cast plates in molds (quartz-cristobalite mixtures) with 20% binder had lower surface hardness and fewer casting porosities than those in molds with 10% binder.

Analysis of Variance↗
PubMed1993

Effect of casting methods on castability of pure titanium.

Two types of patterns were tested for castability: 1) polyester mesh pattern (20mm x 22mm with 100 open squares) and 2) 20mm x 20mm wax plates 1.0 and 1.5 mm in thickness. These materials were invested using a pre-arranged commercial phosphate-bonded investment for titanium. Three different types of casting machines were selected: 1) a pressure-type casting machine with separate melting and casting chambers, 2) a pressure-type casting machine with one chamber and 3) a centrifugal-type casting machine at 3000 rpm. Pure titanium (> 99.5%) was cast into the molds at a mold temperature of 100 degrees C. The castability of mesh pattern was evaluated in terms of the number of cast segment, and the cast plate was evaluated using X-ray transparent images by a digital imaging technique. The centrifugal casting method showed the best castability among these three casting methods.

Dental Casting Technique↗
PubMed1993

Airway inflammation and bronchial hyperresponsiveness in patients with asthma. Comparison between atopic and nonatopic asthma.

A relationship of cellular composition in the airways and the release of chemical mediators from the cells to bronchial hyperresponsiveness was examined in two age-matched asthma groups: 15 atopic and 15 nonatopic patients. 1. A significant correlation between the proportion of eosinophils in bronchoalveolar lavage (BAL) fluid and bronchial reactivity (BR) was found in patients with atopic and nonatopic asthma. The proportion of the cells (combined eosinophils and neutrophils) in BAL fluid was closely correlated with BR in patients with atopic asthma, but not in those with nonatopic asthma. There was no correlation between the proportion of BAL neutrophils and BR in the two asthma groups. 2. There was a significant correlation between histamine release from BAL cells and BR in patients with atopic asthma. In contrast, LTC4 release from BAL cells was significantly corrected with BR in patients with nonatopic asthma. The results suggest that the humoral and cellular components in the airways, that participate in bronchial hyperresponsiveness, are different between patients with atopic and nonatopic asthma.

Adult↗
PubMed1993

[Clinical features of bronchial asthma with mucus hypersecretion].

Fifty patients with bronchial asthma were divided into four groups according to the amount of expectoration per day: 0-24, 25-49, 50-99 and 100+ ml/day. Clinical features of patients with mucus hypersecretion (more than 50 ml/day of expectoration) were evaluated by age, severity of disease, cellular composition of bronchoalveolar lavage (BAL) fluid, and ventilatory function. 1. The proportion of patients with steroid-dependent intractable asthma (SDIA) in each group increased with increase in mucus hypersecretion. 2. Many of the patients with mucus hypersecretion (more than 50 ml/day) were over the age of 40. 3. The proportion of BAL eosinophils was significantly higher in patients with hypersecretion (more than 50 ml/day) than in those with expectoration of less than 49 ml/day. There was a significant correlation between the proportion of BAL eosinophils and the amount of expectoration per day (r = 0.48, p < 0.05). Proportions of lymphocytes and neutrophils in the BAL fluid were not related to the amount of expectoration per day. 4. There was no significant correlation between the amount of expectoration per day and ventilatory function in patients with asthma in this study.

Adult↗