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Biomedical subjects

S Iida

Publications and source records attributed to S Iida.

At least 343 records · Page 19Linked to original sources

Arterial chemoembolization with mitomycin C microcapsules followed by transcatheter hepatic artery embolization for hepatocellular carcinoma.

Of 66 patients with hepatocellular carcinoma, 32 were treated by intraarterial injection of mitomycin C microcapsules (group A) and 34 patients by intraarterial injection of mitomycin C microcapsules followed by transcatheter hepatic artery embolization (group B). Measurable tumor regression greater than 50% in area on liver image occurred in 28% of group A and 57% of group B (p less than 0.05). A decrease of serum alpha-fetoprotein to less than half the initial level was demonstrated in 59% of group A and 91% of group B (p less than 0.05). The survival rate was better in group B compared with group A (p less than 0.05). These results indicate that arterial chemoembolization with mitomycin C microcapsules plus transcatheter hepatic artery embolization will be an improvement over arterial chemoembolization with mitomycin C microcapsules alone in the treatment of hepatocellular carcinoma.

Aged↗

Fatty liver in rats induced by excessive intake of a nutritionally adequate liquid diet.

In order to test whether or not overeating of a nutritionally adequate diet with reasonable fat content could result in significant fat accumulation in the liver, male Sprague-Dawley rats were provided with free access to either a nutritionally adequate liquid diet with 35 per cent of calories as fat or a regular diet (controls) for 3 months. After the feeding period, body weight, Lee index, and epididymal adipose tissue weight, were significantly greater in rats fed with the liquid diet than in the controls. Liver weight, hepatic triglyceride levels were also greater in the liquid diet group. Histologically, remarkable fatty infiltration was observed predominantly in periportal areas in rats fed with the liquid diet ad libitum for 3 months. Compared to a large body of the literature concerning diet-induced obesity in experimental animals, information on animal models of fatty liver by dietary manipulations is insufficient. The results of this study clearly indicate that the overeating of a nutritionally adequate diet with reasonable fat content could result in remarkable fat accumulation in the liver in rats.

Animal Nutritional Physiological Phenomena↗

Measurement of intrahepatic pressure as an index of hepatic sinusoidal pressure.

Intrahepatic pressure was measured in 148 patients with liver disease (32 outpatients, 116 inpatients) and 13 controls with almost normal liver histology (inpatients), with a 23-gauge needle (inner diameter 0.38 mm). Intrahepatic pressure was significantly elevated in the group order of chronic active hepatitis without bridging necrosis (n = 17, 9.2 +/- 3.0 mm Hg), chronic active hepatitis with bridging necrosis (n = 24, 12.3 +/- 5.7), and posthepatitic liver cirrhosis (n = 65, 18.8 +/- 4.2), compared with controls (n = 13, 6.8 +/- 2.7), whereas it was not elevated in the group of idiopathic portal hypertension (n = 9, 7.8 +/- 2.5 mm Hg), acute hepatitis (n = 10, 8.4 +/- 2.6 mm Hg), and chronic persistent hepatitis (n = 23, 7.9 +/- 2.7 mm Hg), compared with controls. As complications, four patients had abdominal discomfort continuing for more than a day; however, patients were allowed to walk after they had rested on their beds for 30 min. In 37 patients (27 with cirrhosis, seven idiopathic portal hypertension, and three others), portal vein and/or hepatic vein catheterization was performed during the same procedure of intrahepatic pressure measurement. Intrahepatic pressure showed significant correlations with corrected wedged hepatic vein pressure (r = 0.91), portohepatic gradient (r = 0.69), wedged hepatic vein pressure (r = 0.79), and portal vein pressure (r = 0.68). Slopes were 0.97, 0.83, 0.66, and 0.65, respectively. In conclusion, intrahepatic pressure reflects hepatic sinusoidal pressure (corrected wedged hepatic vein pressure), and intrahepatic pressure starts to elevate at the stage of chronic active hepatitis.

Acute Disease↗

The effects of endoscopic sclerotherapy combined with transhepatic variceal obliteration on portal hemodynamics.

We studied the effects of endoscopic sclerotherapy with transhepatic variceal obliteration on portal hemodynamics in 20 patients with cirrhosis (six with a spontaneous splenorenal shunt and 14 without it). Portal venous flow 1 month after combined therapy (measured by pulsed Doppler flowmeter) was significantly increased compared with that before therapy (n = 20, 843 +/- 339 vs. 669 +/- 253 ml/min, p less than 0.001). Portal vein catheterization and portal venous flow measurement were repeated 18 months after therapy in eight patients without a splenorenal shunt before therapy and in two patients with a splenorenal shunt before therapy. Two of the former developed a splenorenal shunt. In these 10 patients, portal venous flow before, one month, and 18 months after therapy was 617 +/- 219, 784 +/- 227, and 720 +/- 224 ml/min, respectively, and in 8 of 10 patients the portal venous flow at 18 months remained similar to the values at one month. Portal vein pressures were not significantly elevated 18 months after therapy (35.4 +/- 6.4 vs. 33.6 +/- 5.1 cm H2O) and the mean portal vein pressure change was 2.75 cm H2O (range -6 to +7.5 cm H2O). To summarize, portal venous flow was significantly increased one month after combined sclerotherapy in cirrhotics, the portal venous flow at 18 months remained similar to the values at 1 month in most patients, and the change in portal vein pressure after therapy was small.

Blood Flow Velocity↗

Identification of N-[p-(2-benzimidazolyl)phenyl]maleimide-modified residue participating in dynamic fluorescence changes accompanying Na+,K+-dependent ATP hydrolysis.

Na+,K+-ATPase from pig kidney was specifically modified with a sulfhydryl fluorescent reagent, N-[p-(2-benzimidazolyl)phenyl]maleimide (BIPM), by pretreatment of N-ethylmaleimide. The preparation thus obtained retained 100% of initial Na+,K+-ATPase activity and contained 1 BIPM residue/alpha-chain, and it showed almost 2-fold larger fluorescence changes accompanying ATP hydrolysis than the previous preparations which retained 60% of initial activity and contained 3-4 BIPM residues/alpha-chain (Taniguchi, K., Suzuki, K., and Iida, S. (1982) J. Biol. Chem. 257, 10659-10667). Extensive trypsin (Sigma type I) treatment of the new preparation produced mainly two different fluorescent peptide peaks in both ion-exchange and reverse-phase chromatography. Amino acid sequence analysis of both peptides showed that they had the same common sequence, Ser-Tyr-X-Pro-Gly-Met-Gly-Val, except that the larger one contained Ala-Leu next to the Val residue. From the comparison of the amino acid sequence deduced from cDNA from sheep kidney (Shull, G. E., Schwartz, A., and Lingrel, J. B. (1985) Nature 316, 691-695), X was shown to correspond to Cys-964 of the alpha-chain in Na+,K+-ATPase. The data suggest that the microenvironment of the BIPM residue covalently bound to the sulfhydryl group of Cys-964 changes accompanying sequential appearance of reaction intermediates of Na+,K+-ATPase.

Adenosine Triphosphate↗

The phosphatidylinositide-Ca2+ hypothesis does not apply to the steroidogenic action of corticotropin.

The hypothesis that ACTH (corticotropin) stimulates steroidogenesis by a mechanism that involves breakdown of polyphosphoinositides and increase in intracellular Ca2+ (called here the 'phosphatidylinositide-Ca2+ mechanism') was tested in Y-1 adrenal-tumour cells and in bovine fasciculata cells, by using incorporation of 32P and myo-[3H]inositol to study phospholipid metabolism, and quin-2 and fura 2 to measure intracellular Ca2+. As a positive control, we repeated experiments showing that angiotensin II stimulates glomerulosa cells by way of the phosphatidylinositide-Ca2+ mechanism, by using the same methods. With Y-1 and fasciculata cells, no change was observed in the incorporation of either of the labelled precursors into any phosphatidylinositide or into any of three major phosphoinositols, i.e. inositol phosphate, bisphosphate and trisphosphate. Moreover, no change in mass of any of these compounds was seen. No change was observed in the concentration of intracellular Ca2+ in Y-1 or fasciculata cells on addition of ACTH, by using either quin-2 or fura 2. By contrast, decreased incorporation of 32P into phosphatidylinositol bisphosphate and an increase in intracellular Ca2+ were seen when glomerulosa cells were treated with angiotensin II. It is concluded that the phosphatidylinositide-Ca2+ mechanism is not used by Y-1 adrenal or bovine fasciculata cells in the steroidogenic response to ACTH unless the mechanism is radically different from that seen with all other hormones so far tested in which this mechanism occurs.

Adrenal Glands↗

Localized conversion at the crossover sequences in the site-specific DNA inversion system of bacteriophage P1.

The crossover sites for site-specific C inversion consist of imperfect 12 bp inverted repeats with the dinucleotide TT at the center of symmetry. The phage P1 Cin recombinase acts not only at these cix sites but also less efficiently at cix-related sequences called quasi-cix sites, cixQ. When cixQ contains a central dinucleotide TT, crossover occurs in vivo at the 2 bp sequence TT in the normal and the quasi-cix sites. If cixQ carries only one T residue, inversion-associated localized conversion can occur at the mismatched position within the 2 bp sequence. The results indicate that Cin generates 2 bp staggered cuts in vivo and that reciprocal strand exchanges occur at these 2 bp crossover sequences.

Chromosome Inversion↗

Reversible change in light scattering following formation of ADP-sensitive phosphoenzyme in Na+,K+-ATPase modified with N-[p-(2-benzimidazolyl)phenyl]maleimide.

An increase in light scattering (3.5 +/- 0.2%) was observed when pig kidney Na+,K+-ATPase preparations modified with N-[p-(2-benzimidazolyl)phenyl] maleimide were phosphorylated by ATP in the presence of 2 M Na+ with Mg2+ to form ADP-sensitive phosphoenzyme (E1P), which had a negative fluorescence intensity (-1.5 +/- 0.3%). Addition of K+ or ouabain to E1P reduced the light scattering to the original level observed in the absence of ATP. Stopped flow measurements showed that the fluorescence change accompanying the E1P formation (t1/2 = 0.1 s) occurred preceding the light-scattering change (t1/2 = 1 s). Oligomycin affected the rate of the scattering increase little, but it diminished the effect of K+ on E1P to reduce the light scattering and increase the fluorescence. The addition of 2 M Na+ to K+-sensitive phosphoenzyme (E2P) immediately decreased the fluorescence (t1/2 = 0.02 s) to form E1P which was followed by a slow increase in the light scattering (t1/2 = 0.25 s). Oligomycin reduced both rates of the above changes accompanying the transition of E2P to E1P. The data suggest the sequential appearance of species of E1P that precede E2P formation during the hydrolysis of ATP.

Adenosine Diphosphate↗

Steroidogenic effect of ent-kaur-16-en-15 beta-ol (kaurenol) on isolated rat adrenal cells.

In an in vitro bioassay system for adrenocorticotropic hormone using isolated rat adrenal cells, kaurenol, a diterpene alcohol, stimulated corticosterone production and augmented the steroidogenic effect of adrenocorticotropin or forskolin, dose-dependently. Kaurenol had no effect on cyclic AMP production by the cells. The diterpene also had no stimulatory effect on the adrenal adenylate cyclase activity in a cell free system. The results suggest that this particular diterpene exerts a steroidogenic effect through a mechanism independent of cyclic AMP generation.

Adenylyl Cyclases↗

DNA inversion mediated by the r-determinant of plasmid NR1: evidence for the intramolecular replicative transposition of a 23 kb IS1-flanked transposon?

The r-determinant (r-det) of the R plasmid NR1-Basel is a 23 kb, IS1-flanked transposon, called Tn2671, which has been shown to transpose to the genome of bacteriophage P7. Among the derivatives of phage P7::r-det we found one which carried two copies of the r-det as inverted repeats and which also contained the P7 genome segment between them in inverted orientation. Its generation is best explained by assuming that the entire 23 kb Tn2671 transposon has undergone intramolecular replicative transposition.

Chromosome Inversion↗