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Biomedical subjects

H Kakuta

Publications and source records attributed to H Kakuta.

At least 55 records · Page 3Linked to original sources
PubMed1988

The mechanism of action of quinocarmycin citrate (KW 2152) on mouse L1210 cells in vitro.

The effects of the antitumor antibiotic, quinocarmycin citrate (KW 2152), on L1210 cells were studied in vitro. The cellular growth was completely inhibited at 10(-6) M KW 2152, and after 2 days no viable cell was seen. The incorporation of 3H-thymidine, 3H-uridine, or 3H-leucine into the acid-insoluble fraction was not affected at 10(-4) M for 1 h; however, when the cells were treated with 10(-6) M for 24 h, the radioactivity appearing in the acid-insoluble fraction was reduced to 20%, 30%, and 48%, respectively, of the control. The single strand scission of the DNA of L1210 cells was seen at 10(-7) M for 24 h, as revealed by an alkaline, sucrose density gradient. However, no damage to plasmid pBR322 was observed even at 10(-6) M KW 2152 for 24 h, as revealed by 0.8% agarose gel electrophoresis, indicating that some soluble factors of the cells might contribute to the damage to the DNA of L1210 cells. The processing of pre-rRNA of the cells was not inhibited at 10(-6) M of the drug for 24 h of incubation.

Animals↗
PubMed1988

Efficacy of glucose, ouabain and an aldose reductase inhibitor on 2-[3H] myo-inositol uptake by human, rat and rabbit erythrocytes.

Myo-inositol uptake by erythrocytes from humans, rabbits and rats was studied with an isotope technique. In human erythrocytes, the inhibitory effect on myo-inositol uptake was stronger with glucose than with ouabain. However, an aldose reductase inhibitor (ONO-2235, 100 microM) or insulin (200 microU/ml) failed to correct the decrease in myo-inositol uptake in packed RBC, produced by either 10 mM glucose or 2mM ouabain. Ten mM ouabain had an inhibitory effect on myo-inositol uptake in all species, but an inhibitory effect was not observed with 20 mM glucose in rabbit erythrocytes. The results suggest that myo-inositol uptake by erythrocytes may be dependent on the active transport system via sodium-ATPase and that erythrocytes may not be a suitable model to monitor the possible effect of an aldose reductase inhibitor on myo-inositol concentrations in other tissues concerned with diabetic complications.

Aldehyde Reductase↗
PubMed1987

[The metabolism of high-molecular-weight substances in cells and the effect of anticancer drugs].

The term "high molecular weight substances" used in this paper implies mostly nucleic acids of certain molecular weight and protein, and the genetic aspects of anti-cancer chemotherapy were discussed. Studies on the mechanism of action of 5-FU have been focused on the inhibition of DNA synthesis, and it has been reported that 5-FU inhibits the growth of thymidylate synthesis deleted FM3A Thy 21 cells even in the presence of thymidine, and that the level of TTP is equal to that in control cells. On the other hand, the active metabolite of 5-FU, FdUMP, is known to bind to synthesized thymidylate and 5, 10-methylene-tetrahydrofolic acid to form a ternary complex. Recently, the cytocidal effect of 5-FU was observed in thymidylate synthetase-deficient cells in the presence of a sufficient amount of thymidine, suggesting that the cytocidal effect of 5-FU might be caused by inhibition of the RNA pathway. In this laboratory, the effect of 5-FU on polysomal patterns and the incorporation of 3H-UR into polysomes was studied in L1210 cells, but no significant difference was observed between normal and 5-FU-treated cells. Ribosomal RNA extracted from the polysomes of 5-FU treated cells appeared to contain a smaller 28S rRNA in comparison to 18S rRNA, indicating that the processing might be inhibited. Expression of mouse H-2Dd mRNA was not influenced by 5-FU at 10(-5) M up to 6 h. Methotrexate (MTX) has a chemical structure similar to folic acid, and is known to bind to DHFR (dihydrofolate reductase), and inhibit the synthesis of TMP. The cellular PRPP content is known to be increased by MTX, which inhibits purine synthesis. The level of PRPP content was found to be increased approximately 25 fold at 3 h after 10(-6) M MTX although normal bone marrow cells showed no increase even after MTX. This increased level of PRPP thus obtained in cancer cells was thought to be used for the phosphorylation of 5-FU. Clinically, sequential chemotherapy using MTX and 5-FU was employed successfully for solid tumors on the basis of the experimental evidence. In order to minimize the adverse effects of anti-cancer drugs, a technique involving the incorporation of the drug-resistant gene into normal bone marrow cells has been designed in this laboratory, and the MTX-resistant cells thus obtained are transplanted into the tumor-bearing mice.

Animals↗
PubMed1986

The inhibitory effects of 5-fluorouracil on the metabolism of preribosomal and ribosomal RNA in L-1210 cells in vitro.

Addition of 5FU to the culture medium of mouse L-1210 cells resulted in inhibition of the maturation process of ribosomal RNA precursors in vitro. In the presence of 10(-6) M 5FU for 2 h, the 45S preribosomal RNA was processed to 32S preribosomal RNA, but 28S rRNA was not produced. The processing to 18S rRNA was intact at this drug concentration. Higher concentrations of 5FU for a longer incubation period affected the RNA processing more severely. At 10(-5) M of the drug for 24 h the processing to 28S rRNA and 32S preribosomal RNA. When the cells were labeled with 14C-UR for 2 h following 3H-5FU at 10(-6) M for 24 h, the radioactivities of newly synthesized RNA labeled with 14C-UR accumulated in the region of 45S and 32S preribosomal RNA, and no processing to 28S rRNA was observed. Radioactivity corresponding to 3H-5FU did not persist in the preribosomal RNA region, because further maturation proceeded in the condition of depletion of 5FU after the long incubation period. Thus, inhibition of the processing of preribosomal RNA to 28S rRNA was not brought about by the accumulation of 5FU-substituted 45S preribosomal RNA, but by some other, yet unknown, mechanism.

Animals↗
PubMed1985

Effects of a fructose-rich diet and the aldose reductase inhibitor, ONO-2235, on the development of diabetic neuropathy in streptozotocin-treated rats.

Streptozotocin-diabetic rats were maintained on a 72% fructose diet for 4 weeks and some were treated with an aldose reductase inhibitor (either alrestatin: 0.9 g . kg-1 . day-1 or ONO-2235: 50 mg . kg-1 . day-1). Fructose feeding significantly influenced the development of impaired motor nerve conduction velocity in the diabetic rats and this effect was positively correlated with sorbitol accumulation in the sciatic nerve of diabetic rats maintained on a fructose-rich diet. Treatment with ONO-2235, a new aldose reductase inhibitor, prevented both slowing of motor nerve conduction velocity and elevation of nerve sorbitol concentration. On the other hand, erythrocyte sorbitol levels were significantly correlated to those of the sciatic nerve (r = 0.86, p less than 0.001) and the retina (r = 0.91, p less than 0.001) in these animals. Thus, our findings suggest that increased polyol pathway activity may be related to the pathogenesis of diabetic neuropathy and erythrocyte sorbitol concentrations may prove a useful indicator for the presence of diabetic complications.

Aldehyde Reductase↗
PubMed1985

Effects of aldose reductase inhibitor on retinal microangiopathy in streptozotocin-diabetic rats.

Wistar strain rats were made diabetic by injection of streptozotocin and divided into three groups fed on different diets: conventional solid foods, a fructose-rich diet and a fructose-rich diet mixed with ONO 2235, an aldose reductase inhibitor. The retinas of these rats were examined in flat mount preparations after trypsinization. Microvascular changes such as capillary tortuosity, microaneurysms, pericyte loss, that are typical of diabetic retinal microangiopathy, were seen most frequently in the rats fed on the fructose-rich diet. The rats fed on the fructose-rich diet with ONO 2235 showed much less vascular change than the diabetic rats fed on the conventional food. Electron microscopy of the retina revealed localized thickening of the basement membrane of the retinal capillaries, and this was most frequent in the fructose-fed rats. However, in rats fed on fructose with ONO 2235 the changes of the basement membrane were slight. It was concluded that the aldose reductase inhibitor, ONO 2235, prevented development of diabetic microangiopathy, probably by suppressing the enzymatic activation of aldose reductase in the retina.

Aldehyde Reductase↗
PubMed1983

The features of causes of death in Japanese diabetics during the period 1971-1980.

The principal causes of death among 9,737 diabetics who died in 280 hospitals all over Japan during the period 1971-1980 have been analyzed retrospectively in this study. The main cause of death in Japanese diabetics was vascular complications. The mortality from vascular complications was 41.5%, 37.9% for males and 46.8% for females, increasing with the duration of diabetes and with age. The most interesting findings were of cardiovascular disease which was the cause of death in 12.3% of the subjects in our study as compared to 54.6% of the Joslin Clinic patients (1971). However, our incidence rate was almost twice that reported in Japan in 1967 by Goto (Japan). In contrast, cerebrovascular disease and nephropathy are much more common in Japanese than in American diabetics. Recently cancer has become more common in Japanese diabetics and 25.3% of the deaths have been assigned to it. In contrast, diabetic coma due to hyperglycemia accounted for only 4.1% of deaths. The average life span of Japanese diabetics is still over 10 years shorter than that of non-diabetics.

Adult↗
PubMed1982

[Clinical trial of K-247].

The clinical trial of K-247, an anticancer drug showing antitumor effect by new mechanism of action, was performed in a total of 22 patients with a variety of advanced cancers, consisting of 10 cases administered singly and 12 cases combined with other anticancer agents. All patients were treated three or four times every day with oral administration of K-247 (600-800 mg/day). Including one patient receiving a high dosage (over 200 g totally) of K-247, in all cases, no appreciable side effect causing suspension of the administration was recognized. In combination therapies with other anticancer drugs there was rather found a tendency to rescue WBC from decrease. As a clinical result, although all cases tested were insusceptible to prior chemotherapy with various anticancer drugs, one case, which has received palliative operation for rectal cancer accompanied with pelvic infiltration, was experienced after administration of K-247 only, in which the destructive lesion of left sacral on X-ray photograph was restored to almost normal condition and the patient's complaints such as severe pain in the lower legs and difficulty in walking were completely disappeared.

4-Aminobenzoic Acid↗
PubMed1979

Specific immunotherapy for non-curatively resected gastric cancer.

The prognosis of patients with advanced gastric cancer treated with non-curative resection is very poor. In order to improve patient prognosis, we have tried specific immunotherapy as an adjunct to surgery since January 1968. Sixty-two patients with gastric cancer underwent non-curative resection during the period of this study. Twenty-eight of these patients were treated with specific immunotherapy after surgery, and 34 patients received no additional therapy. The five year survival rate was 35 per cent in the former group, and zero in the latter. No significant difference in the degree of tumor extension and invasion was noted between the two patient groups. We concluded that specific immunotherapy as an adjunct to non-curative resection for advanced cancer is worthy of further study.

Adenocarcinoma↗
PubMed1978

Immunological responsiveness and adjunct immunotherapy in lung cancer.

Immunocompetency was assessed before and after the operation in 40 patients with lung cancer by skin reaction against tuberculin (PPD) and dinitrochlorobenzene (DNCB), lymphocyte response to PHA, proportion of T-cells, macrophage migration inhibition test (MIT) and the presence of blocking factor. MIT was positive in 27 per cent and blocking factor was positive in 42 per cent. Immune response paralleled the clinical stage of the lesion. In curative resection cases, the immune response rose postoperatively, but declined in non-resectable or recurrent cases. The influence of postoperative radiation therapy, cancer chemotherapy and host mediated agents on the patients was observed. The feasibility of adjuvant specific immunotherapy is discussed.

Aged↗