Biomedical subjects
Publications and source records attributed to M Asai.
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To clarify the genesis of the aortic thudding sound (AK), phono-, mechano- and pulsed Doppler echocardiography were performed in 16 patients with pure aortic insufficiency (AI), 3 with AI associated with mild aortic stenosis (AIs) and 5 with AI associated with mitral insufficiency (AI + MI). The results obtained were as follows: 1) AK was composed of two components, that is, one (AK1) occurred in early systole and the other (AK2) near the end point of an ejection systolic murmur. Patients studied were divided into 4 groups following the appearance of AK1 and/or AK2: group with only AK1 (4 cases), group with only AK2 (7 cases), group with both AK1 and AK2 (5 cases) and group without AK (8 cases). 2) AK1 was a low frequency sound and was well recorded from the cardiac base to the right supraclavicular region. AK1 was not observed in cases with mild to moderate AI and with AI associated with mild AS. In atrial fibrillation, when the preceding R-R intervals were long, AK1 was loud and appeared in early systole, and when short, small and in mid-systole. Marked augmentation of AK1 was observed in the first beat after premature ventricular contraction with a compensatory pause. 3) AK2 was also low in frequency and was most intensively recorded near the apex. Although the intensity of AK2 tended to increase in the severe cases of AI, AK2 could be observed in mild to moderate cases. Intensity of AK2 also showed the post-extrasystolic potentiation similar to that of AK1. 4) The carotid pulse showed pulsus bisferiens in all cases with AK2 (group with only AK2 and group with both AK1 and AK2). On the other hand, in cases without AK2 (group without AK and group with only AK1), carotid pulse showed a monophasic systolic wave except 3 cases. These results suggested that there was a close relationship between AK2 and pulsus bisferiens in the carotid pulse. (5) In the apex cardiogram (ACG), systolic notches coincident with AK1 and/or AK2 were observed in 10 of 12 cases with AK2 and in 4 of 9 cases with AK1. In cases without AK, however, no notch was seen in ACG. Therefore, these notches might be resulted from the shock of the anterior chest wall produced simultaneously with the occurrence of AK. 6) Flow patterns at the left ventricular outflow tract (aortic flow patterns) were recorded in 13 cases, including 3 with only AK1, 2 with only AK2, 3 with both AK1 and AK2 and 5 without AK. In 5 of 13 cases the flow patterns were recorded simultaneously with phonocardiograms. Systolic aortic flow showed biphasic patterns in all cases with AK2, and monophasic patterns in cases without AK2. AK1 occurred coincidentally with the first peak of the biphasic flow patterns, and AK2 with the second peak. These results suggested that AK1 might be produced by rapid ejection of massive amount of blood containing a regurgitant flow into the aorta with the ordinarily distensiblwe aortic wall, and AK2 by the clash between the second ejected flow and the reflected flow returning from the peripheral artery against the first ejected flow.
Two new beta-lactam antibiotics, C-19393 S2 (1) and H2 (2), were isolated from the culture filtrate of Streptomyces griseus subsp. cryophilus nov. subsp. The structures were determined by spectral analysis as shown in Fig. 2. The antibiotics have broad antimicrobial activity and strongly inhibit beta-lactamases. The minor product (2) is more stable than cephalosporin C in aqueous solution.
Dnacins A1 and B1, new basic antibiotics with strong and broad antibacterial activities, were isolated as dark red or reddish brown needles from the culture broth of Nocardia sp. No. C-14482. The characteristic absorption maxima at 213 nm, 281 or 283 nm and 496 nm in the UV and visible range and other physicochemical properties indicated that dnacins A1 and B1 are novel antibiotics which belong to the group having aminobenzoquinone moieties.
New antitumor antibiotics, macbecins I and II, were isolated from the culture broth of Nocardia sp. No. C-14919. Macbecins I and II belong to the ansamycin group and have a benzoquinone and hydroquinone nucleus, respectively. Both showed antitumor activity against murine leukemia P 388 in vivo.
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The binding of steroidal alkylating agents to specific tissue component is necessary for the selective distribution of these compounds to their target tissues. The in vivo interaction of Estracyt or NSC-112259 with oestrogen receptors may play an important role in their action mechanism. Both Estracyt and NSC-112259 which were administered in vivo, gradually reduced the binding of [3H] oestradiol to cytoplasmic oestrogen receptor in rabbit uteri. From this, it was suggested that a negligible amount of oestradiol was released from these compounds and that the oestradiol moiety was useful as a carrier for the nitrogen mustard moiety. And it appeared that the synthesis of a new receptor protein was inhibited by the nitrogen mustard moiety, thereby causing a decrease in the cytoplasmic oestrogen receptor level.
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A new assay method was developed to determine the quantity of oestrogen cytoplasmic receptors which are capable of associating with acceptor sites on chromatin. The quantity of oestrogen receptor complexes associated with chromatin is of paramount importance in the mechanism of action of oestrogen. This method is based on the specific binding properties of oestrogen to the receptor and on the binding of the complex to chromatin. Cytosol was pre-incubated with [3H]oestradiol-17 beta ([3H]Oe2) to form a complex, and further incubated with a constant amount of chromatin. After this the quantity of [3H]Oe2 cytosol receptor complexes specifically associated with the chromatin was determined. The binding activity of the chromatin to the [3H]Oe2 receptor complex was stable for at least six months in 0.15 M NaCl at -20 degrees C. This method enables us to determine the quantity of the biologically active oestrogen receptors more specifically than with other methods.
Myocardial metabolism, blood flow distribution within the heart, and coronary and systemic circulations were observed during halothane anesthesia using 15 mongrel dogs. Pao2 and Paco2 were maintained near 100 and 40 torr respectively throughout the study. As arterial halothane content increased, most parameters of systemic circulation were depressed significantly. Coronary blood flow was reduced in parallel with myocardial oxygen consumption (MVo2) (r=+0.89, pless than0.001). Myocardial contractility decreased significantly as anesthesia deepened. MVo2 and myocardial CO2 production were reduced as arterial halothane concentration rose. Arterial-coronary venous difference in blood oxygen content remained unchanged even in deep stage. Lactate and pyruvate were continuously taken up by the myocardium, although the amounts of uptake were reduced as anesthesia progressed. Calculated excess lactate and redox potential did not show any signs of myocardial hypoxia even in deep halothane anesthesia. Among major hemodynamic parameters, left ventricular dp/dt max showed the closest correlation with MVo2. Microsphere injection method was used to observe blood flow distribution within the heart. Halothane did not influence the distribution significantly and I/O ratio of the left ventricular free wall remained near 1.0 during the study.
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