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Biomedical subjects

M Kino

Publications and source records attributed to M Kino.

117 records · Page 7Linked to original sources
PubMed1975

Effects of age on responses to isometric exercise. Isometric handgrip in noninvasive screening for cardiovascular disease.

Isometric handgrip (IHG) imposes an acutely increased afterload on the left ventricle. Utilizing systolic time intervals, we studied various responses to IHG, measured as changes from resting values with near-maximum IHG, in old normal (ON) subjects, young normal (YN) subjects, and old patients with hypertensive heart disease (HHD) and patients with coronary artery disease (CAD). There were no differences in responses to IHG between ON and patients with HHD or patients with CAD. However, there were clear differences between the responses of ON and YN subjects. Increase in heart rate (HR) was much more prominent in YN (ON vs. YN = +11.6 +/- 2.6 vs. +15.6 +/- 5.7 beats per minute p less than 0.001). Pre-ejection period (PEP) end isovolumic contraction time (IVCT) increased in ON but decreased in YN (PEP + 6.2 +/- 1.7 vs. -11.0 +/- 3.7 msec., p less than 0.001; IVCT +8.1 +/- 2.2 vs. -13.8 +/- 3.4 msec., p less than 0.001. Shortening of LVET was much more marked in YN (-6.5 +/- 4.1 VS. -63.3 +/- 9.9 msec. p less than 0.001), but this was entirely due to the HR differences since there was no difference in ejection time index (+ 5.1 +/- 3.4 vs. -0.4 +/- 7.3 msec. p greater than 0.5). IHG produced no significant differences between ON and YN in the timing of the "mitral" component of the first heart sound (q-Im), in the ratio PEP/LVET, or in pulse transmission time (PTT). By contrast, resting control PTT was markedly short in ON, especially those with CAD. Resting PTT in ON was 27.1 +/- 2.6 msec.; in YN 43.7 +/- 1.4 msec.; in CAD patients 20.7 +/- 1.3 msec. We conclude that even near-maximal IHG does not seem to be an adequate noninvasive screening test for cardiovascular disease in that age alone seems to have the most significant influence on the responses.

Adult↗
PubMedDate not supplied

The effect of near-maximal isometric stress on the presence and amplitude of fourth heart sounds.

Near-maximal isometric exercise (IHG) was employed to provoke new, or alter pre-existing fourth heart sounds (S4s) in ambulatory middle-aged normal subjects (N), hypertensive patients (HHD), and patients with coronary disease (CAD). S4 amplitudes and systolic time intervals (STIs) were measured blindly. No subjects without a resting S4 developed a new S4 during IHG. Increases and decreases of pre-existing S4 provoked by IHG were not statistically different among all groups. Among subjects matched for presence of S4, STIs during IHG showed significant shortening of the ejection time index and prolongation of Q-Im in the HHD group only. When the subjects who increased a resting S4 during IHG were compared with the subjects who decreased their resting S4 during IHG there were no significant differences in the responses of STIs. Thus, in these ambulatory, hypertensive patients, coronary patients, and normal subjects, near-maximal IHG did not induce new S4s and had variable effects on pre-existing S4s. Neither type of S4-response could be associated with corresponding changes in systolic time intervals.

Aged↗
PubMedDate not supplied

Cadmium effect on the Na,K-ATPase system in cultured vascular smooth muscle cells.

The present study focuses on the interaction between cadmium (Cd) and the Na, K-ATPase system in in vitro grown vascular smooth muscle cells (VSMCs) derived from the rat carotid artery. In disrupted VSMCs rendered permeable by osmotic shock, Cd inhibited Na, K-ATPase; I50 was reached at 10(-5) M Cd. Mg-ATPase was also inhibited by Cd; I50 was attained at concentrations of 10(-4) M Cd. Cd inhibition of Na,K-ATPase in the VSMCs was noncompetitive with respect to Na, K, and ATP. Rubidium transport experiments performed with intact VSMCs demonstrated that within an incubation period of 150 minutes, a concentration of 10(-4) M Cd in the extracellular fluid exerted no acute effect on the Na-K pump. Within this time interval, intracellular Cd attained a concentration eightfold higher than the extracellular Cd concentration. Thus, it appears that under acute conditions Cd exerts its inhibitory effect on Na, K-ATPase only in disrupted VSMCs. The data further suggest that, in the VSMC, conditions under which Cd inhibits Na, K-ATPase are consistent with inhibition from the cytoplasmic side of the cell membrane.

Animals↗
PubMedDate not supplied

Increased membrane permeability of skin fibroblasts from the spontaneously hypertensive rat.

Recently, we have demonstrated several abnormalities in Na+ and K+ homeostasis in cultured vascular smooth muscle cells derived from spontaneously hypertensive rats (SHR). To study whether similar defects can be identified in other cells of this rat strain, 86Rb and 22Na flux experiments as well as measurements of intracellular Na+ and K+ levels were performed in cultured skin fibroblasts of SHR and normotensive Wistar-Kyoto rats (WKY). The efflux rate constant (ke) for Rb+ (K+ analogue) was higher (p less than 0.001) in fibroblasts of SHR than in those of WKY (2.11 +/- 0.03 and 1.66 +/- 0.02 X 10-2/min; mean +/- SEM). The ouabain-insensitive influx rate constant (ki) for Rb+ was also higher (p less than 0.001) in fibroblasts of SHR than in those of WKY (13.26 +/- 0.41 and 10.71 +/- 0.27 X 10-2/min. On the other hand, the activity of the Na+-K+ pump of cells of SHR (44.81 +/- 0.81 X 10-2/min) was not different from that of cells of WKY (44.72 +/- 0.47 X 10-2/min). This parameter was obtained by calculating the ouabain-sensitive Rb+ influx rate constant. There was also no difference in the Na+ uptake (in the presence of ouabain) between cells of the two rat strains. Although there was no statistically significant difference in the measured intracellular total K+ levels between the two groups, on the basis of equilibrium distribution of 86Rb+, we calculated a significantly lower (p less than 0.001) level of exchangeable intracellular K+ in fibroblasts of SHR (98.2 +/- 1.2 mEq/L) as compared with cells of WKY (115.3 +/- 1.5 mEq/L). These findings indicate increased membrane permeability to K+ in fibroblasts of SHR and that this defect is likely to be innate to their membrane structure.

Animals↗
PubMedDate not supplied

Identification of whale species by thin-layer isoelectric focusing of sarcoplasmic proteins.

Thin-layer isoelectric focusing was applied to the identification of whale (Cetacea) species by using water-soluble sarcoplasmic proteins of skeletal muscles. Twenty-eight samples consisting of 4 species (10 samples) of baleen whales (Mysticeti) and 8 species (18 samples) of toothed whales (Odontoceti) were analyzed. Each sample (approximately 1 g) was electrophoresed with Ampholine PAGplate, pH 3.5-9.5. The electrophoretic profiles were species-specific on the 4 toothed whale species that did not have a marked intra-species difference, and all 4 baleen whale species. However, the profiles were not specific on the 4 other dolphin species, even though they were discriminable from the other 4 toothed whale species. Numerical values of pIs and relative peak heights were obtained by densitometric analysis of the isoelectro-focused protein bands. The bands were also species-specific for the 8 toothed whale species mentioned. The values may be applicable to species identification without the need for a standard sample, which may not be readily obtainable. Experiments on test samples of minke and sel whales showed that bloodletting with ice water made the densities of isoelectro-focused bands thinner, although species identification was still possible by using the inside part of muscles. Heat treatment at below 60 degrees C for 10 min caused little denaturation; at higher temperatures the protein bands were diminished in a temperature-dependent fashion. Therefore, the present isoelectric focusing analysis should be applicable to small samples of whale meat, excluding several species of dolphins.

Animals↗