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Biomedical subjects

H Taniguchi

Publications and source records attributed to H Taniguchi.

At least 577 records · Page 32Linked to original sources
PubMed1988

Inhibitory effect of prolonged administration of cysteamine on experimental carcinogenesis in rat stomach induced by N-methyl-N'-nitro-N-nitrosoguanidine.

The effect of cysteamine (2-aminoethanethiol hydrochloride) on the incidence and histology of gastric adenocarcinomas induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was investigated in inbred Wistar rats. Prolonged administration of 25 or 50 mg per kg body weight of cysteamine after treatment with MNNG for 25 weeks significantly reduced the incidence and number of adenocarcinomas of the glandular stomach. Histological examination showed that the adenocarcinomas that did develop in rats treated with these 2 doses of cysteamine had high mucin-producing activity. Furthermore, treatment with cysteamine caused significant increases in serum gastrin level and gastric acid secretion, together with significant decreases in the antral mucosal pH and the labelling indices of pyloric and oxyntic gland mucosae and gastric cancer. These findings indicate that cysteamine inhibits the development of gastric adenocarcinomas and that its effect may be related to decreasing proliferation of cells in the gastric mucosae.

Adenocarcinoma↗
PubMed1988

Effect of cimetidine on inhibition by tetragastrin of carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Wistar rats.

The effects of combined administration of cimetidine and tetragastrin on gastric acid secretion, the labeling index of the gastric mucosa, and the incidence of gastric adenocarcinomas induced by N-methyl-N'-nitro-N-nitrosoguanidine were investigated in inbred Wistar rats. Prolonged administration of tetragastrin in depot form after treatment with N-methyl-N'-nitro-N-nitrosoguanidine resulted in a significant increase in gastric acid secretion, a significant decrease in the labeling index of the antral mucosa, and a significant decrease in the incidence of adenocarcinomas of the glandular stomach. Administration of cimetidine at 20 mg, but not 10 mg, per kg body weight with tetragastrin significantly reduced the gastric acid secretion induced by tetragastrin alone but did not influence the labeling index of the antral mucosa or the inhibitory effect of tetragastrin on gastric carcinogenesis. These findings indicate that gastric acid secretion has no influence on the development of gastric adenocarcinomas and that the inhibitory effect of tetragastrin on gastric carcinogenesis may be related to its effect in decreasing proliferation of cells in the antral mucosa.

Adenocarcinoma↗
PubMed1988

Inhibition by tetragastrin of experimental carcinogenesis in rat colon: effect of wheat bran consumption.

The effect of dietary wheat bran consumption on the anticarcinogenic action of tetragastrin upon colon carcinogenesis induced by azoxymethane was investigated in 122 inbred Wistar rats. Rats were given a control fiber-free diet or the same basal diet plus 20% wheat bran. From week 5, they were given 250 micrograms per kg body weight of tetragastrin in depot form every other day until the end of the experiment at week 45. Prolonged administration of tetragastrin resulted in a significant reduction of the incidence and number of colonic tumors per rat in the group given the fiber-free diet. The adenocarcinomas that did develop in this group had high mucin-producing activity, unlike the cancers produced in controls without tetragastrin. However, administration of tetragastrin had little or no influence on the incidence, number or histology of colonic tumors in the group given basal diet plus wheat bran. Dietary supplementation with wheat bran alone had little or no effect on the development or histology of colonic tumors. Before and during the administration of carcinogens, addition of fiber to the diet resulted in a significant fall in the colonic pH and a significant increase in the crypt column length, but administration of tetragastrin did not have an additive effect on the crypt column length in rats fed diet supplemented with fiber.

Adenocarcinoma↗
PubMed1988

Surface enhanced resonance Raman study of phenobarbital-induced rabbit liver cytochrome P-450 LM2.

Surface enhanced resonance Raman (SERR) spectroscopy has been used to study the vibrational spectra of the heme of purified rabbit liver cytochrome P-450 LM2 which was adsorbed on colloidal silver suspensions or on a silver electrode. Bases on a comparison with the resonance Raman (RR) spectra of the 'solute' species the high sensitivity of the SERR technique is demonstrated. Two different features were chosen in order to determine the structural and functional integrity of the adsorbed P-450. Both, substrate-induced spin state changes on the oxidized P-450 and the effect of the thiolate ligand on the oxidation state marker band v4 in the reduced P-450 could be observed in the SERR spectra of the adsorbed as well as in the RR spectra of the dissolved enzyme. These findings indicate that the protein structure near the substrate binding site and the coordination by thiolate are not affected by the interaction with the metal surface. Both structural elements are crucial for the function of P-450. Thus the elementary processes of the enzymatic action of P-450 can be investigated by this highly sensitive version of RR spectroscopy.

Adsorption↗
PubMed1988

Transient coappearance of glucagon and insulin in the progenitor cells of the rat pancreatic islets.

Ontogenetic appearances of glucagon, insulin and tyrosine hydroxylase (TH) were immunohistochemically investigated on developing pancreatic islets of rats. Glucagon immunoreactivity appeared first in some epithelial cells (g-cells) of the dorsal anlage of the pancreas on day 11.5 of gestation. On day 12.5, g-cells increased in number manufacturing the primitive islets, in which some cells appeared to be immunoreactive for insulin (i-cells) and about 40% of g-cells indicated also a slight immunoreactivity for insulin (g/i-cells). Afterwards, all the islet cells, especially g-cells, increased in number, and almost half of g-cells were g/i-cells. After day 16.5 of gestation, numerical increase of the cells with insulin immunoreactivity exceeded that of the cells with glucagon immunoreactivity, and about one fifth of g-cells were g/i-cells. After 20.5 days, however, no g/i cells were found. On day 16.5 of gestation, the immunoreactivity for TH appeared in occasional cells of the islets, but the cells did not show immunoreactivity for glucagon or insulin. It is concluded that the progenitor cells of the pancreatic islets appear to synthesize both glucagon and insulin by day 20.5 of gestation, but differentiate giving rise to mature A and B cells of adult islets afterward.

Animals↗
PubMed1988

Phospholipid bilayer membranes play decisive roles in the cytochrome P-450-dependent monooxygenase system.

Hepatic microsomal monooxygenase was reconstituted by incorporating cytochrome P-450 and NADPH-cytochrome P-450 reductase, which had been purified from phenobarbital-pretreated rabbit liver microsomes, into phospholipid liposomal membranes. The NADPH-dependent monooxygenase activity of the reconstituted system was found to be dependent on the phospholipid-to-protein ratio, i.e., the two-dimensional concentration of the two proteins on the plane of the membranes. A similar concentration dependence was also observed in the cytochrome b5 and NADH-cytochrome b5 system, which had been incorporated into liposomal membranes. The diffusion process of the proteins in the membrane, therefore, plays an important role in the monooxygenase system. When the fluidity of the membrane was changed by utilizing a synthetic dimyristoylphosphatidylcholine, which shows a well-defined gel to liquid crystalline phase transition, the activation energy of the monooxygenase reaction was changed at around the phase transition temperature, suggesting a conformational change of cytochrome P-450 caused by the fluidity change of the membrane. The incorporation of P-450 into liposomes was also found to affect the binding of substrates to cytochrome P-450. The decrease in the apparent dissociation constant of substrates upon incorporation into membranes suggests that the lipid membrane acts as a pool for hydrophobic substrates, which are concentrated in the lipid phase, and that cytochrome P-450 takes substrates directly from the membrane phase. Phospholipid membranes, therefore, play very important roles in various phases of the reaction of cytochrome P-450-dependent monooxygenase.

Animals↗
PubMed1988

Intracellular Ca2+ mobilization in immature and more mature U937 induced to differentiate by dimethyl sulfoxide or phorbol myristate acetate.

Intracellular Ca2+ mobilization in U937 cells was studied. Stimulation of immature U937 cells with leukotriene B4 (LTB4) increased intracellular Ca2+ levels, whereas stimulation with N-formyl-methionyl-leucyl-phenylalanine (fMLP) failed to increase intracellular Ca2+ levels. U937 cells cultured with 1.5% dimethyl sulfoxide (DMSO) for 4 days (DMSO-U937 cells) responded to LTB4 and possessed the ability to respond to fMLP. U937 cells cultured with 1 ng/ml phorbol myristate acetate (PMA) for 4 days (PMA-U937 cells) lost the ability to respond to LTB4, although they responded to fMLP. Treatment of DMSO-U937 cells with 100 ng/ml PMA for 3 min suppressed intracellular Ca2+ increase induced by LTB4 and fMLP. The fMLP-induced Ca2+ rise in PMA-U937 cells was not suppressed by a further treatment with 100 ng/ml PMA. DMSO-U937 cells responded to inositol 1,4,5-trisphosphate (IP3), indicating that IP3 functions as a messenger of intracellular Ca2+ mobilization from endoplasmic reticulum in U937. The magnitude and duration of the rise in Ca2+ induced by IP3 in DMSO-U937 cells treated with 100 ng/ml PMA for 3 min were similar to those of the controls. When DMSO-U937 cells were Ca2+-depleted, addition of Ca2+ resulted in a transient overshoot of Ca2+ influx. However, the transient overshoot was not observed, when PMA-U937 cells were tested. These results indicate that Ca2+ efflux in PMA-U937 cells is increased by an activated exit pump, which may be directly or indirectly related to the functional state of PMA-U937 cells.

Calcium↗
PubMed1988

Increase in collagen production with loss of androgen responsiveness in cultured androgen-responsive Shionogi carcinoma 115 cells.

The collagen production of androgen-responsive and -unresponsive Shionogi carcinoma 115 cells was investigated by culturing them in a medium with or without testosterone. Androgen-unresponsive cells were obtained by culturing a cloned androgen-responsive cell in a testosterone-free medium for 12 weeks. The collagen production of androgen-responsive cells slightly increased in the absence of testosterone, whereas testosterone did not affect the collagen production of androgen-unresponsive cells. Androgen-unresponsive cells produced 3-4 times more collagen than androgen-responsive cells. The major collagen produced by both androgen-responsive and - unresponsive cells migrated to the same position in sodium dodecylsulfate:polyacylamide gel electrophoresis. The present results indicate that the collagen production of androgen-responsive Shionogi carcinoma 115 cells increases with the loss of androgen responsiveness in culture.

Animals↗
PubMed1988

An improved method for the isolation of islets from the rat pancreas.

The conventional method for rat islet isolation was improved by injection of collagenase solution (1.3 mg/ml) into the bile duct and the concomitant dissection of the inferior vena cava, static incubation of the removed distended pancreas for 15 min at 37 degrees C and filtration of the digested tissue through two different meshes of 1190 and 590 micron in pore size. This new technique led to about 2.5 times higher yield of viable islets than the conventional method.

Animals↗
PubMed1988

Development of spindle-shaped cells and chondroid cells from androgen-dependent Shionogi carcinoma 115. A light and electron microscopic study.

Androgen-dependent Shionogi carcinoma 115 (SC115) is an undifferentiated medullary carcinoma consisting of compact round cells. However, when host male DS mice were castrated 2 weeks after tumor transplantation, tumors composed of compact round cells, spindle-shaped cells and chondroid cells grew 4 weeks after castration. Compact round cells with desmosomes were arranged in solid nests and exhibited immunoreactivity for keratin protein. Spindle-shaped cells had prominent rough endoplasmic reticulum, and appeared to secrete collagen. Chondroid cells had the characteristics of chondrocytes. The light and electron microscopic features were highly suggestive of a transition from compact round cells to spindle-shaped cells, and from spindle-shaped cells to chondroid cells. The histology of this tumor thus suggests that SC115 cells are able to change into chondroid cells via spindle-shaped cells.

Androgens↗
PubMed1988

Anti-rat myoglobin antisera in the immunocytochemical diagnosis of rhabdomyosarcomas of rats.

Anti-rat myoglobin (Mb) was prepared and used in the avidin-biotin-peroxidase complex (ABC) method on paraffin-embedded sections of nine soft tissue tumors (including two rhabdomyosarcomas) of rats. Distribution and nature of the reactive substance to Mb antiserum were compared to those of desmin antiserum. Rat Mb was isolated from the skeletal muscle; monospecificity of the rat antiserum was confirmed by the immunoblotting procedures. The Mb antiserum reacted specifically to normal and neoplastic striated muscle cells. Mb-staining reactions were present diffusely in the cytoplasm, while desmin-staining substances were localized at Z-bands or were diffuse in the cytoplasm as separated aggregates. Reaction to the Mb serum was also detected in cells of thick portions of Henle's loop and distal convoluted tubules.

Animals↗
PubMed1988

[Microscopic changes in the human liver after intra-arterial infusion of anticancer agents suspended in lipiodol].

Microscopic injury to the human liver after an intraarterial infusion of anti-cancer agents suspended in lipiodol has been evidenced by Hematoxylin-Eosin staining and by Oil Red O staining. In cases involving primary hepatic tumors, the liver tumor tissue has been injured severely while normal tissue showed no injury. In cases involving metastatic liver tumors, the tumor tissue, and also the normal liver tissue was injured though the latter injury was only mild. However, when multi-anticancer agents that were suspended in lipiodol were infused intra-arterially, the normal liver tissue was injured, even from a single drug suspension.

Antineoplastic Agents↗
PubMed1988

[Cytofluorometric and histopathological studies on non-cancerous liver lesions after lipiodol-transcatheter arterial embolization].

We have investigated the effects of preoperative Lipiodol-Transcatheter arterial embolization (Lp-TAE) on both the nuclear DNA content of noncancerous liver cells by DNA-cytofluorometry (using NIKON SPM-RF1-D), and the histopathological findings of liver lesions. Lp-TAE through the hepatic artery was performed on ten primary hepatocellular carcinoma patients using Gelfoam in combination with adriamycin (40 mg) or mitomycin C (20 mg), emulsified in Lipiodol (10 ml) and 60% Urografin (2 ml). And hepatic resection was carried out after one or two months later in each case. Histologically, primary hepatocellular carcinoma lesions showed various patterns of necrosis, while the non-cancerous liver cells did not show hepatocellular infarction in the liver cirrhosis. The results of the nuclear DNA content showed an increase in the fractions of poliploid cells in the non-cancerous lesions treated with Lp-TAE compared with that in the normal age-matched controls. But we found no remarkable differences in the ploidy patterns between Lp-TAE treated patients and untreated patients with liver cirrhosis. In conclusion, preoperative Lp-TAE does not induce any remarkable histological hepatocellular damage of non-cancerous lesion and does not affect nuclear DNA content of non-cancerous liver cells.

Adult↗
PubMed1988

[Advantages and disadvantages of L-TAE in diagnosis and treatment of hepatocellular carcinoma].

Transcatheter arterial embolization using lipiodol ultra-fluid (L-TAE) is frequently used for hepatocellular carcinoma (HCC). Its advantages are: (1) Excellent therapeutic and diagnostic ability in our pathological study of 153 resected tumors. (2) Preoperatively, we can localize HCC and prevent spreading of cancer cells by manipulation at hepatectomy. (3) Postoperatively, we can detect and treat recurrence early, and we hope to prevent recurrence by repeated L-TAE. (1) Liver infarction has occurred after L-TAE, because some lipiodol flows into the portal vein. Lipiodol remains long in the infarction area and interferes with the diagnosis of HCC. (2) Liver abscess has rarely occurred. (3) Repeated L-TAE does not impair the liver function much.

Carcinoma, Hepatocellular↗
PubMed1988

[Trans-arterial embolization or transarterial infusion of anti-cancer drugs suspended in a lipid contrast medium against unresectable metastatic liver cancer].

We had 84 patients with unresectable metastatic liver cancer from May, 1980 to December 1987 in the National Matsudo Hospital. Eighteen of them had no treatment; 26 of them had serial transarterial embolization (TAE) with or without infusion of anti-cancer drug dispersed in lipiodol; 7 of them had only serial trans-arterial infusion (L-TAI) of an anticancer drug suspended in lipiodol. A significant survival advantage of patients with TAE or L-TAI was noted when compared with no treatment, but there was no difference between the survival rate of patients with TAE and L-TAI. There were some 82 patients with unresectable metastatic liver cancer from October 1984 to March 1988 in Kyto Prefectural University of Medicine Hospital. Thirteen of them had L-TAI using one anti-cancer drug (one-drug group); 8 of them had L-TAI using two drugs (two-drug group); 22 of them had L-TAI with three drugs (three-drug group). The survival rate of the three-drug group was superior to the one- and two-drug groups. It was concluded that TAE was not necessary for metastatic liver cancer, but L-TAI must be undertaken, because combined cancer chemotherapy enhanced the effect of L-TAI.

Antineoplastic Combined Chemotherapy Protocols↗