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Biomedical subjects

F Hayashi

Publications and source records attributed to F Hayashi.

At least 199 records · Page 11Linked to original sources
PubMed1981

Relative contributions of chemical and non-chemical drives to the breath-holding time in breath-hold divers (Ama).

Relative contributions of chemical and non-chemical respiratory stimulations to breath-holding time (BHT) were examined in assisted (Funado) and unassisted (Kachido) breath-hold divers (Ama). In the Funado the magnitude of the chemical contribution was reduced, though statistically not significantly. On the other hand, in the Kachido no difference in chemical contribution was seen from the control. This was considered to be due to the fact that ventilatory response to CO2 was reduced in the Funado, but not in the Kachido. Despite the decreased contribution of CO2 drive to BHT, absolute BHT in the Funado was no prolonged. This may be related to sensitization of the respiratory centers to non-chemical stimulation. Such adaptation would be effective for preventing the danger of losing consciousness in the Funado who face extreme hypoxia on returning to the surface from a dive.

Adaptation, Physiological↗
PubMed1981

The ventilatory responses to hypoxia and hypercapnia in the Ama.

The ventilatory responses to hypoxia and hypercapnia of 5 Amas (Kachido) were compared with those of 5 controls of similar ages, physical characteristics and lung volumes. The responses to hypoxia and hypercapnia were analyzed by the equations originally proposed [a] by Lloyd et al. and [b] by Kronenberg et al. as follows: (See the formula in the text) The CO2-response slope in hyperoxia, D, of the Ama (1.820 +/- 0.441 liters . min-1 . Torr-1) was slightly higher than that of the control (1.148 +/- 0.586 liters . min-1 . Torr-1), but the difference was not significant. However, the slope of CO2-response in hypoxia at PETO2 = 44 Torr, S44, was almost the same in the two groups (Ama, 1.822 +/- 0.689 liters . min-1 . Torr-1; control, 1.742 +/- 0.902 liters . min-1 . Torr-1). The ratio of S44 to D was significantly lower (p greater than 0.05) in the Ama (1.039 +/- 0.377) than in the control (1.529 +/- 0.249). Comparing the hypoxic response in terms of the ventilation ratio (VR), the elevation of ventilation with augmentation of hypoxia in the Ama was exceeded by that in the control. Thus, it was suggested that the difference in the ventilatory response to hypoxia between the Ama (Kachido) and the control may have been derived from the respiratory adaptation of the Ama (Kachido) acquired by their daily diving activities.

Adaptation, Physiological↗
PubMed1981

[The measurement of individual differences in interpersonal cognitive structure (6): Age and sex differences of perceivers (author's transl)].

The purpose of the present study was to examine age and sex differences in "implicit personality theories (IPT)." Forty-four undergraduates and 77 junior high school students served as subjects in personality perception as obtained by the Repertory Grid method. Responses were analyzed by means of Carroll and Chang's INDSCAL model. The results were: (a) The dimensional structure of IPT for the older subjects were more complicated than that for the younger ones; and (b) for the younger subjects, males perceived role persons in less differentiated manners than did females.

Adolescent↗
PubMed1979

Conformation of adenosine 3',5'-monophosphate in solution as studied by the NMR-desert method. II. Self-association and temperature-dependent glycosidic isomerization at pH 7.

A study has been made of the association and the temperature-dependent conformation of adenosine 3',5'-monophosphate (cyclic AMP) in a neutral aqueous (2H2O) solution by means of proton magnetic resonance chemical shift and relaxation. The concentration and temperature-dependent chemical shifts of H(1'), H(2), and H(8), have enabled us to estimate the self-association constant, Ka = 1.1 +/- 0.3 M-1 at 25 degrees C and thermodynamic parameters delta H = -5.8 +/- 1.5 kcal/mol and delta S (25 degrees C) = -19.0 +/- 3 cal/mol per degree. The NMR-DESERT (Deuterium Substitution Effect on Relaxation Times) method has been utilized for the determination of the syn-anti conformational equilibrium in the monomeric state and for the determination of the mutual orientation of the two adenine rings in the dimeric state of cyclic AMP. The molecules were found to coexist with nearly equimolarity or syn-anti conformers and thermal activation of the molecules perturbs the syn-anti conformational equilibrium to comprise the syn form in preference at higher temperature. The glycosidic isomerization (from anti to syn) was found to be characterized both by a positive enthalpy change and by a positive entropy change. The cyclic AMP molecules prefer to take a 'trans-stacking' conformation in the dimeric state where the two molecules are arranged in such a way that the H(2) of one molecule is close to the H(8) of the other.

Chemical Phenomena↗
PubMed1978

31P-NMR study on nucleotides and intracellular pH of hereditary spherocytes.

As determined by 31p-NMR spectroscopy, intracellular pH of hereditary spherocytes was lower (pH 6.7-6.9) than that of normal red cells. The level of adenosine diphosphate in hereditary spherocytes was found to be persistently high. The metabolism of nucleotides and other phosphoryl compounds in human red blood cells have been studied in detail by 31p-MNR spectroscopy. However, to our knowledge, there seems to be no report describing the result of 31p-NMR spectroscopy on red blood cells from hereditary spherocytosis.

Adenosine Diphosphate↗
PubMed1978

Calcium-sensitive univalent cation channel formed by lysotriphosphoinositide in bilayer lipid membranes.

A calcium sensitive univalent cation channel could be formed by lysotriphosphoinositide on an artificial bilayer membrane made of oxidized cholesterol. The modified membrane was selectively permeable to univalent cations, but was only very sparingly permeable to anions or divalent cations. Selectivity sequence among group IA cations was Rb+ greater than Cs+ greater than Na+ greater than K+ greater than Li+. The conductance of the membrane was increased up to a value of about 10-2 ohm-1/cm2 with an increase in the concentration of univalent cation, and was drastically depressed by a relatively small increase in the concentration of calcium ion or other divalent cations. The sequence of depressing efficiency among divalent cations was Zn+ greater than Cd2+ greater than Ca2+ greater than Sr2+ greater than Mg2+.

Calcium↗