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Biomedical subjects

S Suehiro

Publications and source records attributed to S Suehiro.

At least 145 records · Page 8Linked to original sources
PubMed1982

Different reflex responses in cardiac and renal sympathetic nerve activities during coronary occlusion in the dog.

This study was undertaken to scrutinize the difference in the response of cardiac sympathetic nerve activity (CSNA) and renal nerve activity (RNA) to coronary artery occlusion. The magnitudes and time courses of per cent changes in CSNA and RNA, recorded simultaneously in 22 dogs, were compared with each other during a 1 min occlusion of the left circumflex coronary artery under four different conditions. With afferent nerve intact, changes in CSNA and RNA showed similar biphasic patterns comprising initial increases (CSNA, 9 +/- 3.1% (S.E.); RNA, 16 +/- 6.4%, at 20 sec of occlusion) and subsequent decreases (CSNA, -3 +/- 4.3%; RNA, -11 +/- 6.5%, at 60 sec), despite the progressive fall in arterial pressure (from 109 +/- 4 to 89 +/- 4 mmHg). After carotid sinus denervation, the initial increases in both nerve activities were reduced and the subsequent decreases became more evident. The decreases in RNA (-47 +/- 8.0%) were significantly greater than those in CSNA (-23 +/- 5.6%). After bilateral cervical vagotomy, changes in both CSNA and RNA showed in contrast similar monophasic increasing patterns (CSNA, 18 +/- 4.0%; RNA, 25 +/- 5.6%, at 60 sec), where RNA increased more than did CSNA. After carotid sinus and vagoaortic denervation, CSNA and RNA increased only slightly throughout the occlusion. These results conclusively indicate that the reflex responses in CSNA and RNA during coronary occlusion are quantitatively different, though qualitatively similar, and that RNA is inhibited significantly more than CSNA by the reflex mediated through the afferent vagal nerves.

Animals↗
PubMed1981

Regression of cardiac oxygen consumption on ventricular pressure-volume area in dog.

Left ventricular systolic pressure-volume area (PVA) has been reported to be a reliable predictor of cardiac oxygen consumption rate per beat (VO2) in a given heart with a stable inotropic background. PVA is the specific area in the pressure-volume (PV) diagram, consisting of the area (EW) within the PV loop and the area (PE) bound by the end-systolic and end-diastolic PV lines and the relaxation segment of the PV loop. EW and PE correspond to the external mechanical work and the end-systolic elastic potential energy in the ventricular wall, respectively. We determined the optimal combination of EW and PE for the best prediction of VO2, using the linear multiple regression analysis. From EW, PE, and VO2, data of many isovolumic and ejecting contractions, the optimal coefficients of EW and PE were 1.67 +/- 0.43 (SD; 7 hearts) and 1.74 +/- 0.49 (10(-5) ml O2/mmHg . ml), virtually identical to each other, corroborating that PVA, i.e., a simple sum of EW and PE, can reliably predict VO2 of a given heart in a stable contractile state.

Animals↗
PubMed1981

Equal oxygen consumption rates of isovolumic and ejecting contractions with equal systolic pressure-volume areas in canine left ventricle.

Left ventricle systolic pressure-volume area (PVA) has been found to be highly linearly correlated with cardiac oxygen consumption rate per beat (VO2) in a given canine heart with a stable inotropic background. PVA is a specific area in the pressure-volume (P-V) diagram that is bounded by the end-systolic and end-diastolic P-V relationship lines and the systolic segment of the P-V loop, consisting of the sum of external mechanical work and what is considered the end-systolic elastic potential energy in the ventricular wall. In this study, we compared VO2's of steady state entirely isovolumic and variously ejecting contractions that were made to have equal PVA's in the canine left ventricle. We found that VO2's of these isovolumic and ejecting contractions with equal PVA's (isovolumic vs. ejecting = 1008 +/- 64 (SE) vs. 1022 +/- 62 mm Hg ml/beat, n = 32 pairs in 10 hearts) were equal to each other (0.0375 +/- 0.0021 vs. 0.0368 +/- 0.0021 ml O2/beat) regardless of the marked differences in stroke volume (0 vs. 9.8 +/- 0.6 ml), end-diastolic volume (20.3 +/- 0.8 vs. 23.7 +/- 0.9 ml), end-systolic volume (20.3 +/- 0.8 vs. 13.9 +/- 0.7 ml), peak pressure (123 +/- 5 vs. 88 +/- 5 mm Hg), stroke work (0 vs. 636 +/- 36 mm Hg ml/beat), and calculated peak total wall force (1588 +/- 77 vs. 1077 +/- 72 g). Therefore, we conclude that PVA can serve as a reliable predictor of VO2 in a given canine left ventricle with a stable inotropic background whether the contraction mode is isovolumic or ejecting.

Animals↗
PubMed1973

Release and recovery of forespores from Bacillus cereus.

A method is described which makes possible the release of immature forespores from sporulating cells at specific stages of development, from the completion of stage III through to mature spore formation. With the aid of zonal density gradient centrifugation, the method makes possible the recovery of quantities of forespores ample for biochemical and physical studies. With the capability to examine forespores and some mother cell components independently, we have established that several enzymes associated with the sporulation process are localized in the newly developed forespores. Studies showed that aspartate aminotransferase and alanine aminotransferase are associated with the forespores, whereas l-alanine dehydrogenase is found only in the mother cell cytoplasm.

Alanine↗