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Biomedical subjects

I Ikeda

Publications and source records attributed to I Ikeda.

At least 181 records · Page 10Linked to original sources
PubMed1980

Resistance of red blood cell membrane to oxygen uptake.

The apparent association velocity constant (k'c) was determined before and after disruption of the red blood cell membrane in one of several ways: 1) radiation of the cells using a 137Cs source did not significantly alter k'c (95 +/- 39.3 and 118 +/- 35.5 mM-1.s-1), 2) incubation of the cells with sialidase produced no change in k'c (112 +/- 42.6 and 123 +/- 46.8 mM-1.s-1), 3) using papain for the incubation similarly produced no significant alteration in k'c (94 +/- 21.2 and 113 +/- 51.8 mM-1.s-1), 4) a radiomimetic agent p-chloromercuribenzene sulfonate likewise produced no significant alteration in k'c (128 +/- 16.3 and 122 +/- 3.5 mM-1.s-1), and 5) employing phospholipase C to disrupt the membrane k'c did not significantly change (115 +/- 15.3 and 112 +/- 8.7 mM-1.s-1). We conclude that either O2 traverses the membrane in a manner uninfluenced by the manipulations here employed, or that the membrane offers no significant resistance to the speed of O2 uptake.

Erythrocyte Membrane↗
PubMed1978

The distribution of dietary plant sterols in serum lipoproteins and liver subcellular fractions of rats.

Rats were fed plant sterols containing campesterol and beta-sitosterol in the differerent proportions, and their distribution in serum lipoproteins and in liver subcellular fractions was determined. In serum lipoproteins, the percentage as well as the concentration of plant sterols increased with the increase in the density of lipoproteins. Thus, high density lipoprotein (HDL) contained the highest and very low density lipoprotein (VLDL), the lowest. Also, there were distinct differences in the ratio of campesterol to sitosterol among lipoproteins, it was the highest in VLDL and lowest in HDL. Quantitatively, more than 75% of campesterol and 80% of sitosterol were carried in HDL; the values were significantly different from those of cholesterol (ca. 70%) in relation to total cholesterol. The distribution of plant sterols in liver subcellular fractions was virtually the same with that of cholesterol. Both nuclei and microsomes contained approximately 40% of total plant sterols.

Animals↗
PubMed1978

Comparison of absorption and metabolism of beta-sitosterol and beta-sitostanol in rats.

The fates of [4-14C]beta-sitosterol ([14C]S) and [4-14C]beta-sitostanol ([14C]HS) were compared after after oral or intravenous administration to rats. Excretion into feces of oral [14C]HS was significantly higher than that of [14C]S. More than 97% of [14C]HS and 88% of [14CS]S were recovered in the feces within 7 days. Thus, deposition of [14C]HS was negligible in the tissues that were examined. Turnover in serum of [14C]HS which was injected intravenously appeared to be more rapid than that of [14C]S; [14C]HS was excreted as neutral steroids at a rate more than twice that of [14C]S. The rate of excretion of [3H]cholesterol was slightly greater when HS was administered simultaneously. The liver contained significantly less radioactivity after [14C]HS than after [14C]S administration. More [14C]HS than [14C]S was present in esterified form in serum and liver. The ratio of sterol in very low density lipoprotein to that in high density lipoprotein was less for HS or S than for endogenous cholesterol; this was particularly marked with HS. These results suggest that HS would be a more effective hypocholesterolemic agent than S.

Administration, Oral↗
PubMed1977

Plasma hormone profile of threatened abortion and its prognosis.

Hormone levels in patients with threatened abortion were compared with those of women with normal pregnancies to determine the relationship between these hormone patterns and patient prognoses. Plasma progesterone, plasma unconjugated estradiol-17beta (estradiol), and plasma human chorionic somato-mammotropin (HCS) were measured serially in 27 patients with threatened abortion. Twelve of these patients were able to continue their pregnancies, and 15 patients aborted. Of the 3 indices tested, 2 (plasma estradiol and HCS levels) showed marked differences in women who were able to continue their pregnancies and women whose pregnancies ended in abortions; moreover, these findings indicated that these 2 levels could be used as indices for the evaluation of a pregnant patient's prognosis.

Abortion, Threatened↗
PubMed1977

A comparison of hypocholesterolemic activity of beta-sitosterol and beta-sitostanol in rats.

The hypocholesterolemic activity of beta-sitosterol and its hydrogenated product, beta-sitostanol (dihydrositosterol or stigmastanol) has been compared in young male rats. When cholesterol was included in the diet, sitostanol consistently exhibited significantly greater hypocholesterolemic activity than sitosterol. There were no apparent differences in the effects of the sterol and the stanol on the concentration of liver cholesterol and triglyceride. Increases in plasma triglyceride due to feeding sitosterol were not observed with sitostanol. Incorporation of dietary sitostanol into plasma, liver and other tissues was always negligible, and thus this stanol was almost completely recovered in feces, while there was considerable deposition of sitosterol (mean fecal recovery being 85% to 92%). The increase in fecal output of dietary cholesterol was significantly greater with the stanol than with sterol. There was no demonstrable negative effect on growth and weight of major visceral tissues in rats fed the sterol as well as the stanol. These observations together with those reported previously indicate that hydorgenation of phytosterols is a novel approach to enhance their hypocholesterolemic activities without influencing the relative safety of the initial sterols.

Adipose Tissue↗
PubMed1977

Preparation of various Tc-99m dimercaptosuccinate complexes and their evaluation as radiotracers.

The organ distributions of four different Tc-99m dimercaptosuccinate complexes ("Tc-DMS", Complexes 1 to 4) were determined using mice and were evaluated as renal imaging agents. The highest kidney uptake was observed with Complex 2:21.7% of dose, 3 hr after injection. The biologic distributions and gel chromatographic analyses using carrier Tc-99 and Sn-113 indicate that there is little possibility of mixed metal complexes of the type Tc-Sn-DMS: rather they contain only Tc + DMS. The labeling procedure for Tc-99m DMS as a renal agent proceeds in two steps: a rapid formation of Complex 1, and a slower, rate-determining step from Complex 1 to Complex 2. A reproducible lyophilized kit has been prepared. The yield of complex 2 greatly depends on the reconstitution volume of 99mTcO4-; yield averages 89% using 2 ml of 99mTcO4-eluate.

Animals↗
PubMed1977

Basic studies of various 99mTc-labelled renal agents and clinical application of 99mTc-malate.

Various renal imaging agents that were reported in the past and a new agent, 99mTc-malate as well as99mTc-cystein acetazolamide complex were prepared using electrolysis and electrochemical methods. These were studied for their labelling efficiency. After animal experiments with selected 99mTc-compounds, 99mTc-malate proved to be sufficient for renal imaging with adequate concentration. 99mTc-malate differs from other renal imaging agents in the utilization of endogeneous metabolic product. The first half time of 99mTc-malate in humans is 17 minutes, on the average, and the urinary excretion rate of 99mTc-malate is 36+/-6.05% in 1 hour after intravenous administration, 44+/-3.41% in 2 hours and 50+/-5.62% in 3 hours. In our 40 clinical experiences of 99m-Tc-malate, most cases demonstrated quite clear renal images in the serial scintiphotos except cases whose serum creatinines were over 4.5 mg/dl.

Acetazolamide↗
PubMed1976

New preparation method for 99mTc-phytate.

A new method is described in which Pt-Sn or Sn-Sn electrodes are used to activate 99mTcO4-. The 99mTc is incorporated into phytic acid by stannous ion released from a tin anode by the corrosive reaction. The most suitable pH for labeling phytic acid by this method was below 5 and the 99mTc-phytate formed could be precipitatedd with Ca+2 at a pH above 3.5. Though 99mTc-phytate is soluble in aqueous solution, it forms an insoluble species with Ca+2 in vivo and is trapped in the reticuloendothelial system. More than 93% of the 99mTc-phytate localized in the liver of mice; here its biologic half-time is about 112 hr. The 99mTc-phytate prepared by this method promises to be useful as a liver-scanning agent. Since our method does not require an applied electric potential, it appears to be one of the most convenient methods for labeling compounds with 99mTc.

Animals↗