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Biomedical subjects

T Ide

Publications and source records attributed to T Ide.

At least 325 records · Page 18Linked to original sources
PubMed1984

Effects of different levels of dietary trans-octadecenoate on steroid metabolism in rats.

Rats were fed semipurified diets containing olive oil or partially hydrogenated corn oil at the 5 or 20% level for ca. 30 days. These fat diets contained the same amount of octadecenoate but differed in the geometry with respect to each fat level. Contents of t-18:1 were 26% and 41% of total fatty acids, respectively. The linoleic acid content was also made equivalent (3.8 energy %). After feeding on cholesterol-free diets, rats on trans fat, compared to those on cis fat, showed: (a) no changes in serum cholesterol and apolipoprotein levels, (b) no effects on the bile flow and concentrations of biliary cholesterol or bile acids, (c) a trend toward increased fecal excretion of neutral and acidic steroids, (d) a lesser extent of transformation of cholesterol to coprostanol in the gut, and (e) no changes in the composition of biliary and fecal bile acids. Observations (c) and (d) were more marked with a high trans fat regimen. These observations, except for serum apolipoproteins and fecal steroid excretion, were practically reproducible even when rats were fed cholesterol-enriched diets.

Animals↗
PubMed1984

Progress of aging in human diploid cells transformed with a tsA mutant of simian virus 40.

Normal human diploid cells, TIG-1, ceased to proliferate at about the 62 population doubling level (PDL). Transformed clones isolated from TIG-1 cells infected with wtSV40 and those with tsA900 SV40 cultured at 34 degrees C were subcultured up to about 80 PDL. When the culture temperature of tsA SV40-transformed cells was shifted from 34 to 39.5 degrees C at 51 PDL, the growth curve of these transformed cells changed to that of normal young cells. When shifted to 39.5 degrees C after 62 PDL, cells immediately reached the end of their proliferative lifespan even under such favourable conditions for growth as low cell density in fresh medium. Growth of wtSV40-transformed cells did not change markedly at either temperature. These findings suggest that the clock of aging progresses in transformed cells as in normal cells, around 62 PDL being the senescent state in both cases, and that T-antigen of the tsA mutant of SV40 supports the extension of the lifespan of human cells only at the permissive temperature.

Antigens, Viral, Tumor↗
PubMed1984

Isolation of a G0-specific ts mutant from a Fischer rat cell line, 3Y1.

A ts mutant clone, tsJT60, was isolated from Fisher rat cell line, 3Y1. During the exponential growth at both 34 and 39.5 degrees C, tsJT60 did not appear as ts mutant cells. However, once entered resting state (G0) under serum deprivation at the confluent state, they could re-enter S phase at 34 degrees C but could not at 39.5 degrees C following the stimulation of cells either by the addition of fetal bovine serum or by trypsinization and replating. These and other results suggested that tsJT60 is a G0-specific ts mutant, i.e., the cells have ts defect(s) in the function which is required for the stimulation from the resting state to S phase but not for the progression of the cell cycle in an exponential growth phase.

Animals↗
PubMed1984

Effect of dietary fat on lipid secretion and ketone body production in rat liver.

Perfused livers from rats fed different fats were used to examine the effect of dietary fat on the rat of hepatic lipoprotein synthesis and fatty acid metabolism. Dietary fats (10% level) used were safflower oil (18:2), camellia oil (18:1) and tristearin (18:0). The results were compared with those obtained from rats fed on a low-fat diet (1% safflower oil). When no oleate substrate was infused, triglyceride secretion rates were approximately the same among the different fat groups. Infusion of the fatty acid substrate increased the secretion of triglyceride to a similar extent in 10% fat groups while the magnitude of increase was more pronounced in the low-fat group. The magnitude of increases in ketone body production due to fatty acid supply was dependent either on the amount or the type of fat; the smallest on a low-fat diet and the greatest on a camellia oil diet. Rates of secretion cholesterol and phospholipid were modified by neither the amount nor the type of fat used. It was suggested that dietary fat may alter the rate of fatty acid catabolism without modifying lipoprotein synthesis. Safflower oil distinctly modified the fatty acid profile of triglyceride secreted. Polyunsaturated fat may exert its potent hypocholesterolemic effect through the modification of the composition of lipoprotein secreted.

Animals↗
PubMed1984

The distribution of 3-hydroxy-3-methylglutaryl coenzyme A reductase in the small intestine of rats fed raw or gelatinized starch as a carbohydrate source.

The effect of gelatinization of dietary starch (wheat, corn and potato) on the distribution of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase along the small intestine of rats was studied in villus and crypt cell populations isolated by graduated scraping. Gelatinized starch preferentially stimulated jejunal reductase activity in both villus and crypt cells and consequently retained the ileojejunal gradient for the reductase activity which is characteristic for rats fed on a sucrose- or glucose-enriched semi-purified diet. The distribution of the reductase in rats fed the raw starches, however, depended on the degree of gelatinization of the preparations; raw wheat starch maintained the ileojejunal gradient, whereas the corn or potato starch eliminated the gradient, and with the latter in particular, the reductase activity tended to be higher in the ileum than in the jejunum. The digestibility of dietary starches seems to be closely related to the intertissue distribution of the intestinal HMG-CoA reductase activity.

Animals↗
PubMed1984

[Fundamental study on ceftriaxone].

Ceftriaxone (CTRX) was examined in the blood level and urinary excretion between a healthy group of 2 persons receiving 1 g CTRX for 1 day and the other of 3 patients with renal failure receiving 1 g for 3 days, both by intravenous injection or intravenous drip infusion. In the healthy group, the blood half-life time of CTRX was 6.0 hours in 1 person and 8.2 hours in the other, being 7.1 hours on average. The mean blood level in the healthy group was 199 micrograms/ml at peak and was 13 micrograms/ml at 24 hours after administration. In patients with renal failure, the peak blood level ranged from 136.8 to 161.1 micrograms/ml on the 1st day, from 163.1 to 217.0 micrograms/ml on the 2nd day and from 156.4 to 189.7 micrograms/ml on the 3rd day, showing no tendency of getting higher, while the bottom level did from 15.2 to 47.4 micrograms/ml on the 1st day, from 23.3 to 67.9 micrograms/ml on the 2nd day and from 10.9 to 72.6 micrograms/ml on the 3rd day. The urinary excretion rate was 54.6 +/- 3.7% on average in the healthy group while it ranged from 13.7 +/- 1.8 to 27.9 +/- 7.9% in the patient group. CTRX was effective especially against E. coli among the strains clinically isolated from the patients with renal failure. No side effects were observed in any case.

Adult↗
PubMed1984

Reversible inactivation-reactivation of 3-hydroxy-3-methylglutaryl coenzyme A reductase of rat intestine.

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase in the ileum of rats was inactivated by Mg2+-ATP and reversibly reactivated by cytoplasmic activator from the liver. The mevalonate kinase reaction was presumably not involved in this inactivation. Studies of nucleotide specificity for the inactivation revealed that ATP was most effective in the reaction among the nucleotides tested. In contrast to the hepatic microsomal HMG-CoA reductase, more than one-half of intestinal reductase existed in an active form. These observations indicated the presence of phosphorylation-dephosphorylation mechanism for modulation of intestinal HMG-CoA reductase.

Adenosine Triphosphate↗
PubMed1984

Cholesterol dynamics in rats fed cis- and trans-octadecenoate in the form of triglyceride.

The cholesterol dynamics were compared in rats fed diets containing either camellia oil or partially hydrogenated corn oil as a source of cis- and trans-octadecenoate, respectively. The diets contained approximately the same amount of octadecenoic acid, and an equivalent amount of linoleic acid. In rats fed the trans-fat for about 30 days, liver cholesterol levels were clearly low relative to levels in rats fed the cis-fat, while the concentration of serum cholesterol and the distribution of cholesterol in serum lipoproteins were comparable. The activity of hepatic microsomal 3-hydroxy-3-methylglutaryl coenzyme A reductase and the incorporation of [I-14C]acetate into digitonin-precipitable sterols in the liver homogenate tended to increase in rats fed the trans-fat diet. Cholesterol 7 alpha-hydroxylase activity increased significantly. Cholesterol absorption measured by the dual isotope serum ratio method was markedly lower, and much more radioactivity both from orally and intravenously administered cholesterol was excreted quickly into feces in the trans-fat group, with relatively more excretion in the neutral than in the acidic steroids. Apparent absorption of dietary fat was slightly lower in the trans-fat group. Cholesterol turnover as analyzed according to the two-pool model was much faster in rats fed trans-fat and the pool A size was reduced mainly as a consequence of stimulation of the removal rate from this pool. The intestinal epithelial cells contained relatively more trans-octadecenoate compared to the serum and liver and trans-fat modified the lipid composition specifically. These observations suggest that the changes in cholesterol metabolism due to the ingestion of trans-fat, compared to cis-fat, are as a result of metabolic events in the intestine.

Absorption↗
PubMed1983

Effect of clofibrate on the metabolism of oleate in the perfused rat liver.

The effect of clofibrate on the metabolism of [1-14C]- and [U-14C]oleate was examined in the perfused rat liver. Clofibrate feeding severely reduced hepatic triglyceride secretion and enhanced ketone body production. The increase in the rate of incorporation of labeled tracers into perfusate oxidation products and ketone bodies due to the clofibrate treatment was demonstrated only with [U-14C]oleate. Clofibrate strongly reduced the rate of incorporation of oleate into perfusate triglyceride, whereas that into the phospholipid fraction of the post-perfused liver doubled. In consequence, the sum of the radioactivities in esterified lipids in the perfusate and the post-perfused liver was not altered by clofibrate. A clofibrate-dependent increase in phospholipid synthesis may restrict the amount of exogenous fatty acid which is available for the formation of triglyceride-rich lipoproteins.

Animals↗
PubMed1983

Biliary and fecal steroid excretion in rats fed partially hydrogenated soybean oil.

Male Wistar rats were fed cholesterol-free or cholesterol-enriched diets containing partially hydrogenated soybean oil with different levels of trans-fatty acids or unhydrogenated soybean oil at the 10% level. The linoleic acid content of hydrogenated fat diets was adjusted to 3.6% of the total energy. Hydrogenated fat diets contained 29% and 41% trans-acids, mainly as t-18:1. Trans-fats exerted no untoward effects on growth parameters, but increased liver weight. Dietary hydrogenated fats influenced neither the concentration nor composition of biliary steroids, irrespective of the presence or absence of cholesterol in the diet. In rats fed a cholesterol-free diet, daily fecal output of neutral and acidic steroids was enhanced by hydrogenated fats and the magnitude of augmentation was proportional to the dietary level of trans-fatty acids. The increased fecal steroid excretion corresponded to an increase in total excreta. Hydrogenated fats also tended to enhance bile acid excretion when feeding a cholesterol-enriched diet. The results suggest that dietary trans-fatty acids, in relation to cis-polyunsaturated fatty acids, provoke demonstrable change in steroid homeodynamics.

Animals↗
PubMed1983

Effects of dietary trans-fat on biliary and fecal steroid excretion and serum lipoproteins in rats.

Rats were fed cholesterol-free or cholesterol-enriched diets containing olive oil or partially hydrogenated corn oil at the 10% level for ca. 30 days (c-18:1, 77.0% in the former diet and c-18:1,24.7% and t-18:1,42.5% in the latter). The linoleic acid content of these fat diets was made equivalent (1.7 energy %). After feeding cholesterol-free diets, trans fat compared to cis fat showed (a) no untoward effects on growth parameters, (b) a reduction of serum cholesterol levels without influencing concentrations of serum apolipoproteins A-1, B and E, (c) no effects on the bile flow and the concentration of biliary cholesterol and bile acids, (d) an increasing trend of fecal excretion of neutral and acidic steroids, both in terms of mg/day and mg/g feces, and (e) rather equivocal change in the composition of fecal, but not biliary steroids. Similar response patterns were also observed when cholesterol-enriched diets were fed except for a decrease in serum apo B and an ineffectiveness to increase fecal acidic steroids. Together with the results obtained from experiments simultaneously performed with safflower oil and completely hydrogenated corn oil, it seems that the steroid metabolism can be specifically modified by the geometry of dietary fats.

Animals↗
PubMed1983

Reinitiation of host DNA synthesis in senescent human diploid cells by infection with Simian virus 40.

Human diploid fibroblasts, TIG-1, cease to proliferate at about 60-62 population doubling level. In their senescent state used in this study, the percentage of nuclei labeled by [3H]thymidine for 48 h was around 1-2% in fresh medium containing 5-40% fetal bovine serum. The percentage of labelled nuclei increased up to 10-fold after infection with SV40. This increase reflects stimulation of cell DNA synthesis because: 1. The increase also occurred when ts A900 was used for infection at the non-permissive temperature, under these conditions viral DNA synthesis is inhibited; 2, the increase paralleled the stimulation of [3H]thymidine incorporation into DNA in a Hirt-precipitate fraction from SV40-infected cells. UV-irradiated SV40 had reduced ability to induce DNA synthesis. A viable deletion mutant of SV40, d1940, had almost the same activity to induce cell DNA synthesis as did wild-type SV40. Equilibrium density gradient centrifugation analysis of DNA labelled with 5-bromodeoxyuridine (BrdU) supported semiconservative replication rather than repair synthesis. We conclude that a considerable fraction of human diploid cells in a senescent population initiate host DNA replication by infection with SV40, although these cells cannot be stimulated with fetal bovine serum.

Antigens, Viral↗
PubMed1983

Correlation between the presence of T-antigen and the reinitiation of host DNA synthesis in senescent human diploid fibroblasts after SV40 infection.

Senescent human diploid fibroblasts, TIG-1, had labelling indices of about 0.5-3% when labelled with [3H]thymidine for 3 days in fresh medium containing 10% fetal bovine serum. When these cells were infected with SV40, the percentage of nuclei incorporating [3H]thymidine increased by about 10-fold. The frequency of T-antigen-positive cells and that of [3H]thymidine-incorporating cells were almost the same. About 80% of T-antigen-positive cells were also positive to incorporation of [3H]thymidine, and the same result was obtained in infected young cells. These results indicated that senescent human diploid cells which are brought to synthesize T-antigen always initiate DNA synthesis as young cells do. The characteristics of senescent cells as compared with younger cells was low incidence of T-antigen-positive cells after infection. The basis of low susceptibility of senescent cells to initiate DNA synthesis by SV40 infection thus seems to be concerned with an event after the adsorption of virus, but before the synthesis of a detectable amount of T-antigen.

Antigens, Viral↗