Search PubMed⌕ Search

Biomedical subjects

K Akasaka

Publications and source records attributed to K Akasaka.

At least 181 records · Page 10Linked to original sources
PubMed1975

Peptide hydrogen exchange rates in Streptomyces subtilisin inhibitor.

The exchange reaction of the peptide NH protons of a microbial protease inhibitor (Streptomyces subtilisin inhibitor) with deuterium atoms in 2H2O (p2H 6.8) has been studied by proton magnetic resonance in the temperature range 56-71 degrees C. Both slowly and rapidly exchanging processes have been observed. The number of slowly exchanging protons is estimated to be 25 +/- 2 per subunit of the protein molecule. The decay of the slowly exchanging proton signals follows a single time-exponential function at each temperature. The observed first-order rate constants have been analyzed to give the denaturated fraction of the protein as a function of temperature with a consequent enthalpy (56 kcal/mol) and an entropy (137 cal/degree per mol) of denaturation. The results indicate the high conformational stability of this protein against heat denaturation.

Bacterial Proteins↗
PubMed1975

Effects of beta-adrenergic stimulating and blocking agents on the adrenaline response and adenyl cyclase activity of leukocyte in monkey and human being.

Using the method in which leukocyte suspensions were incubated with NaF or metaproterenol at 30 degrees C for 15-30 min to allow them to convert 3H-ATP (10 muCi) to 3H-cyclic AMP, followed by separation of the formed 3H-cyclic AMP by common chromatography, the leukocyte adenyl cyclase activity of monkeys and human beings was measured with high reproducibility. The oral administration of metaproterenol increased the leukocyte adenyl cyclase activity which was stimulated by NaF and decreased the count of peripheral eosinophils in some of the monkeys. In the beta-adrenergic blockade of the monkey which was made by administration of propranolol, the leukocyte adenyl cyclase activity significantly decreased. The leukocyte adenyl cyclase from patients with coronary heart disease also decreased after oral medication with propranolol.

Adenylyl Cyclases↗
PubMed1975

Leukocyte adenyl cyclase activity in human bronchial asthma.

Changes in adenyl cyclase activity of the peripheral blood leukocytes were investigated in patients with bronchial asthma. Estimation of the leukocyte adenyl cyclase activity was carried out following in vitro stimulation by sodium fluoride (NaF) or metaproternol. The NaF-stimulated adenyl cyclase activity was significantly lower during asthmatic attacks. An oral administration of metaproterenol to patients during an attack was found to enhance the activity back to the control levels. Off-attack asthmatic patients showed a normal value which was again elevated considerably when they were administered metaproterenol. In contrast, measurements of adenyl cyclase activity using metaproterenol stimulation showed little change in patients in spite of asthmatic attacks or metaproterenol regimen. The lowering of the NaF-stimulated leukocyte adenyl cyclase activity was inversely proportional to the degree of lymphopenia during attacks and positively correlated with an increasing percentage of neutrophils.

Adenylyl Cyclases↗
PubMed1975

Acoustical studies on respiratory sounds in asthmatic patients.

Changes in the breathing sounds such as stridor and dry and wet rales in asthmatic patients were studied. The breathing sounds were recorded with the small transistor warp type microphone inserted through the nasal orifice into the trachea, main bronchi and segmental bronchi, and were analyzed with sound analyzer. The results were as follows: The whistling rales were caused by the resonance of the bronchial wall, when the vibrating frequency was coincident with its specific frequency. Snoring rales were explained as the sound caused by the air flow passing promptly through contracted bronchi with little secretion. Resonance of either bronchial wall or highly viscous sputum was considered to be responsible for the sonorous rales. Sibilant rales were audible when bronchi promptly repeated dilation and contraction. Stridor was picked up at the upper part of the air tract, from the main bronchus to the trachea, and noise was the main component on the sonogram, presumably caused by the air turbulence due to the narrowing and deformity of bronchial tube or to the sputum adhering to the inner surface of the air tract.

Adolescent↗
PubMed1975

A new electrode for electromyographic study of bronchial smooth muscle.

The contribution of the bronchial smooth muscles to asthmatic attack has been supposed by many studies such as measurement of the intrabronchial pressure and bronchographical studies, but electromyographical evidence has not been established yet. A new bipolar platinum-ring electrode fixed on polyethylene catheter was invented in order to record action potentials from the bronchial smooth muscle through the intrabronchial lead. Action potentials obtained by this electrode were compared with those obtained by the direct peribronchial needle electrode during either artificial or spontaneous respiration in dogs and a monkey. Electrophotographical analysis confirmed that action potentials obtained by our new electrode were similar in discharge pattern to those by the direct peribronchial needle electrode. The active contribution of the bronchial smooth muscle to the maintenance of the bronchial caliber during spontaneous respiration was observed by our new electrode. Accordingly, this electrode is applicable to electromyographical studies of the bronchial smooth muscle.

Action Potentials↗
PubMed1975

Electromyographic study of bronchial smooth muslce in bronchial asthma.

We succeeded in recording action potentials from the bronchial smooth muscles in 10 healthy males and 20 cases of bronchial asthma by means of the new electrode described by us in the preceding paper (Akasaka et al. 1975). From these electromyographic studies, we presented the direct evidence of spasm of the bronchial smooth muscles as one of the etiological factors responsible for the airway narrowing in asthmatic attack.

Action Potentials↗
PubMed1975

A study of western red cedar-induced asthma.

Seventeen asthmatic patients who were workers dealing with Western Red Cedar in a Japanese wooden frame factory were studied. One fraction from the aqueous extract of the lumber induced a positive skin test, Prausnitz-Kustner test and the inhalation test. This confirms the existence of antigen in Western Red Cedar and its ability to produce allergic asthma in sensitive workers.

Acetylcholine↗
PubMed1975

A study of Western Red Cedar sensitivity: workers' allergy reactions and symptoms.

In 154 individuals who work with Western Red Cedar in Japanese wooden frame factories a high incidence (24.7%) of bronchial asthma was observed. A positive intradermal test was found in 89% of the asthmatics and in 56% of all. A highly positive inhalation test was obtained only in the asthmatic group. It is suggested that other symptoms in addition to bronchial asthma might be caused by Western Red Cedar because of the frequency of positive skin reactions to the Western Red Cedar antigen.

Asthma↗