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Biomedical subjects

T Nishio

Publications and source records attributed to T Nishio.

At least 181 records · Page 10Linked to original sources
PubMed1984

Torsional motion of eosin-labeled F-actin as detected in the time-resolved anisotropy decay of the probe in the sub-millisecond time range.

The internal motion of F-actin in the time range from 10(-6) to 10(-3) second has been explored by measuring the transient absorption anisotropy of eosin-labeled F-actin using laser flash photolysis. The transient absorption anisotropy of eosin-F-actin at 20 degrees C has a component that decays in the submicrosecond time scale to an anisotropy of about 0.3. This anisotropy then decays with a relaxation time of about 450 microseconds to a residual anisotropy of about 0.1 after 2 ms. When the concentration of eosin-F-actin was varied in the range from 7 to 28 microM, the transient absorption anisotropy curves obtained were almost indistinguishable from each other. These results show that the anisotropy decay arises from internal motion of eosin-F-actin. Analysis of the transient absorption anisotropy curves indicates that the internal motion detected by the decay in anisotropy is primarily a twisting of actin protomers in the F-actin helix; bending of the actin filament makes a minor contribution only to the measured decay. The torsional rigidity calculated from the transient absorption anisotropy is 0.2 X 10(-17) dyn cm2 at 20 degrees C, which is about an order of magnitude smaller than the flexural rigidity determined from previous studies. Thus, we conclude that F-actin is more flexible in twisting than in bending. The calculated root-mean-square fluctuation of the torsional angle between adjacent actin protomers in the actin helix is about 4 degrees at 20 degrees C. We also found that the torsional rigidity is approximately constant in the temperature range from 5 to approximately 35 degrees C, and that the binding of phalloidin does not appreciably affect the torsional motion of F-actin.

Actins↗
PubMed1984

Digestion of protein substrates by subtilisin: immobilization changes the pattern of products.

Subtilisin BPN' (Bacillus protease strain N') was immobilized on glass-bead carriers of controlled pore size by the glutaraldehyde method. The Vmax and Km values of the synthetic substrate were similar for immobilized and free enzymes. However, the hydrolytic patterns of immobilized and free enzymes toward casein and carboxymethylated lysozyme were different. The free enzyme rapidly hydrolyzed the substrate in the early stage of the reaction to produce peptides of various sizes. The immobilized enzyme, however, slowly digested the casein and lysozyme during digestion; even in the late stage of digestion the original substrates were present in the reaction mixture. The peptide size produced by immobilized enzyme depended on the pore size of the carrier; enzyme immobilized on glass of smaller pore size produced smaller peptide products. These phenomena found with our system of immobilized protease and a protein substrate can be explained by a multiple attack mechanism, in which the substrate that has been forced to enter the matrix is attacked many times by the protease to be completely hydrolyzed, because the substrate and the intermediate-sized product are trapped inside the matrix under reduced diffusion movement. To explain the effective digestion that forms amino acids, we have proposed that a multiple type of attack is responsible for the intracellular protein degradation that takes place in cellular organelles in which hydrolytic enzymes are entrapped.

Caseins↗
PubMed1984

The relationship between blood pressure and left ventricular muscle volume in normal children and adolescents--the Shimane Heart study.

Blood pressure (BP) and left ventricular muscle volume (LVMV) were measured in 408 children and adolescents aged 9-15 years. LVMV was determined by M-mode echocardiography. Lean body weight was approximately calculated using body weight, upper arm circumference and triceps skin fold thickness. Lean-BSA was obtained by substituting lean body weight for body weight in the formula for BSA. Subjects were divided into the high and the low BP percentile groups according to their BP percentile values. LVMVI (= LVMV/BSA) and lean-LVMVI (= LVMV/L-BSA) were compared between the two groups. LVMVI and L-LVMVI were larger in the high BP percentile group than in the low one. Regression lines of LVMV to BSA were also compared between the two groups. Regression lines of the high BP percentile group were located in a higher position than those of the low percentile group. These results suggest that LVMV are larger in the high BP percentile group than in the low percentile group even if their BSAs are equal. We concluded that left ventricular hypertrophy has been already initiated in the pre-hypertensive stage of human beings as observed in spontaneously hypertensive rats.

Adolescent↗
PubMed1984

Computer analysis of frank vectorcardiograms in normal children--maximal spatial QRS vector.

Frank vectorcardiograms recorded on magnetic tape were analyzed by a computer. The study population was 835 normal children aged from 6 to 16. Magnitudes, angles (azimuth, elevation) of the maximal spatial QRS vector and QRS duration were calculated. The magnitude of maximal spatial QRS vector increased significantly in males compared to those in females at ages 9-10, 11-12 (p less than 0.01) and 15-16 (p less than 0.001). Though there was no significant difference of elevation in either sex, azimuth tended to move more anteriorly in females than in males. QRS duration in males became longer with increasing age, while in females at age 15-16, it decreased (p less than 0.001).

Adolescent↗
PubMed1984

A network data base system for children with cardiac disease--echocardiographic data of MCLS.

We developed a computer-assisted network data base system for children with cardiac diseases. It aims at storage and exchange of medical information from many hospitals to prevent school children from sudden death caused by heart diseases. The computer system used was PANAFACOM U-1500 introduced at Shimane Medical University Hospital in 1980. The format of the questionnaire is designed to standardize the computer-assisted data-entry method among different hospitals. The entries of questionnaires are composed of basic information about the patient and laboratory information. The former is identification data of the patient, and the latter principally the values of M-mode echocardiographic measurement. Two types of output-tables were made from the data base. One is a table of each disease, and the other each hospital.

Child↗
PubMed1984

Measurement of cardiac output by the thermodilution method in conscious spontaneously hypertensive rats.

The usefulness of the thermodilution method for measuring cardiac output (CO) was evaluated in awake rats by comparison with electromagnetic flowmetry. CO was measured in 3- and 6-month-old conscious spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). The correlation co-efficient between CO obtained by the two methods was 0.66 (p less than 0.01). Although CO values obtained by the thermodilution technique tended to be overestimated in comparison with those determined by electromagnetic flowmetry, this method was shown to be useful for measuring CO in unanesthetized rats because of its technical simplicity. Left ventricular mass (LVM) and the ratio of CO to LVM were significantly greater in SHR than in WKY at both ages and CO/LVM increased with increasing age in SHR. The ratio of heart work (HW) to body weight (HW/BW) was increased only in 3-month-old SHR compared with WKY and there was no difference in HW/LVM in 3- and 6-month-old SHR compared with age-matched WKY. The present results suggest that the development of cardiac hypertrophy in SHR is an adaptation to the increased HW due to high afterload.

Aging↗
PubMed1983

Specific binding of chartreusin, an antitumor antibiotic, to DNA.

Chartreusin, an antitumor and antibacterial antibiotic, was found to inhibit negatively superhelical DNA-relaxation catalyzed by prokaryotic topoisomerase I and conversion of the superhelical DNA into unit length linear form catalyzed by single-strand-specific S1 nuclease. The inhibitory effect of the agent was due to the binding to DNA causing the alteration of tertiary structure. To characterize the binding specificity, we investigated the protection of DNA against cleavages by various restriction endonucleases. It was evidenced that the binding of the agent is not at random and correlates to the sequence 5'CGC 3' 3'GCG 5' on DNA stretch.

Antibiotics, Antineoplastic↗
PubMed1983

Internal motion of F-actin in 10(-6)-10(-3) s time range studied by transient absorption anisotropy: detection of torsional motion.

By means of laser flash photolysis, the transient absorption anisotropy (TAA) of the triplet probe, 5-iodoacetamide-Eosin, labeling rabbit skeletal F-actin was measured in the 10(-6)-10(-3) s time range. The TAA curve at 20 degrees C showed a relatively slow decay phase covering several hundred microseconds and a large residual anisotropy (approximately 0.1 at 2 ms). After analysis with Barkley & Zimm's formula, it was concluded that the TAA of Eosin-F-actin can be approximated by the anisotropy decay due to torsional motion of F-actin.

Actins↗
PubMed1983

Static and kinetic studies on rabbit skeletal muscle troponin.

Fluorescence titration curves of 2-[4'-iodoacetamido)anilino)naphthalene-6-sulfonic acid-labeled troponin (IAANS-labeled Tn) and troponin-1-anilinonaphthalene-8-sulfonic acid (Tn-ANS) complex indicated that the fluorescent moiety, IAANS or ANS, detects conformational change of troponin I (TnI) or Tn due to the Ca2+ binding or removal reaction with the low affinity Ca2+-binding sites of troponin C (TnC) component. A fluorescence stopped-flow study showed that the kinetic behavior of IAANS-labeled Tn reflects a change in state of the TnI component induced by the Ca2+ binding or removal reaction with the low affinity Ca2+-binding sites of TnC component. The state change of TnI induced by the Ca2+ binding was complete within the instrumental dead time. On the other hand, that induced by the Ca2+ removal had a rate constant of around 13 s-1. ANS, which is noncovalently bound to Tn, reflects the kinetic properties of both the TnI component and the low affinity Ca2+-binding region of TnC component. The fluorescence intensity change of ANS induced by Ca2+ binding to the low affinity Ca2+-binding sites of TnC was complete within the instrumental dead time, while that induced by the Ca2+ removal from the same sites was biphasic. The rate constants of the biphasic process were found to be 62 +/- 7 s-1 and 16 +/- 4 s-1. The former value corresponds to the rate constant of the Ca2+ removal reaction from the low affinity Ca2+-binding sites of TnC component, and the latter value to the rate constant observed in the case of IAANS-labeled Tn. Based on these experimental results and on the discussion in our previous paper (Iio, T. & Kondo, H. (1981) J. Biochem. 90, 163-175), we have refined the two-way information-transfer mechanism which we previously proposed in order to explain the biological function of Tn.

Actins↗
PubMed1983

Estimates of denitrification and nitrification in coastal and estuarine sediments.

Denitrification and nitrification in sediments of Tama Estuary and Odawa Bay, Japan, were investigated by the combined use of a continuous-flow sediment-water system and a N tracer technique. At Odawa Bay, the nitrification rate was comparable to the nitrate reduction rate, and 70% of the N(2) evolved originated from nitrogenous oxides (nitrate and nitrite) which were produced by the action of nitrifying bacteria in the sediments. At Tama Estuary, the nitrate reduction rate was 11 to 17 times higher than the nitrification rate, and nitrogenous oxides derived from ammonium accounted for only 6 to 9% of the N(2) evolution by denitrification.

Journal Article↗
PubMed1983

Relationship between cardiac parameters and cube root of BSA corrected by subcutaneous fat weight.

Left ventricular internal dimension (LVIDd), aortic root dimension (AOD) and left atrial dimension (LAD) were measured echocardiographically in 688 normal children, ranging in age from 5 to 15. Lean body surface area (BSA) was calculated from height and lean body weight which was estimated from triceps skin fold thickness, upper arm circumference and body weight. Cardiac parameters (LVIDd, AOD, LAD) were well correlated with 3 square root BSA or 3 square root lean BSA (r = 0.72 approximately 0.89). Regression lines of LVIDd and AOD against 3 square root BSA or 3 square root lean BSA were compared between boys and girls. Statistically significant sex difference was observed in regression lines of LVIDd and AOD plotted against BSA (p less than 0.005), but this difference disappeared when plotted against lean BSA. It is concluded that the sex difference of LVIDd and AOD corresponding to a similar BSA depended on the difference of lean body weight between boys and girls.

Adipose Tissue↗
PubMed1983

Genetic properties of conjugative R plasmids in Escherichia coli and Salmonella isolated from feral and domestic pigeons, crows and kites.

A total of 62 conjugative R plasmids detected in 48 Escherichia coli and 19 conjugative R plasmids in 16 Salmonella strains from domestic (carrier and emerald) and feral pigeons, crows (Japanese jungle crows and carrion crows) and black kite, were examined for genetic properties. Out of the 62 E. coli R plasmids examined for fertility inhibition (Fi), 29 (46.8%) were Fi+, and the remainder were Fi-. Among the 62 R plasmids, 16 (25.8%) were classified into incompatibility (Inc) group FII, 15 (24.2%) into I alpha, 7 (11.3%) into H1 and 2 (3.2%) into N. The remaining 23 R plasmids could not be classified in this study. Among the 19 Salmonella R plasmids, 4 showed thermosensitive (ts) transfer. Out of the 18 plasmids tested, 13 (72.2%) including 4 ts-R plasmids were Fi-, and the remaining 5 (27.8%) were Fi+. Five R plasmids containing 4 Fi- were IncI alpha, while 4 ts-R plasmids belonged to IncH1 (1 R plasmid) and H2 (3 R plasmids). The remainings were not tested. In E. coli strains, IncFII and I alpha were widely (4 of 6 lots of birds, respectively) distributed, followed by N (2 lots) and H1 (1 lot). IncN R plasmid was detected from domestic pigeons and crows, but not from feral pigeons. In Salmonella strains from 5 lots of birds, IncFII and N plasmids which were detected from E. coli were not found, but IncH2 was detected from domestic pigeons (1 lot) and kite (1 lot). IncI alpha was detected from feral pigeons (1 lot) and kite (1 lot). The potential transfer of R plasmids between Salmonella and E. coli, and of dissemination of the plasmids among the free-flying birds, animals and humans is discussed.

Animals↗