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Biomedical subjects

M Yamaguchi

Publications and source records attributed to M Yamaguchi.

At least 1,531 records · Page 85Linked to original sources
PubMed1986

[Sensitivity test of anticancer agents by subrenal capsule assay (SRC assay). II--Determination of tumor sensitivity by percentage inhibition of DNA protein].

Subrenal capsule assay(SRC assay) has been reported to be an effective and rapid method for predicting the tumor sensitivity of individual patients to anti-cancer agents. In order to establish a more objective method of determining sensitivity in SRC assay the DNA content was measured by the schmidt-Thannhauser-Schneider method and the protein content was estimated using Bio-Rad protein assay, after removal of a tumor implanted in the subrenal capsular space of ddY mice. Percentage inhibition of DNA/protein had a high correlation with that of relative increase of tumor weight, although three groups treated with mitomycin-C, 5-fluorouracil and cyclophosphamide indicated different values of tumor sensitivity. From these results, the percentage inhibition of DNA/protein seems to be more objective than microscopic measurement for predicting tumor sensitivity.

Animals↗
PubMed1986

[In vitro phase II-III study by clonogenic assay: the combined effects of mitomycin C with alpha-interferon].

Using the human tumor clonogenic assay technique, the combined effects of mitomycin C (MMC) with alpha-interferon (HLBI) were surveyed in comparison with 33 fresh human tumor specimens. Tumors in this study were 16 gastric cancers, five breast cancers, four liposarcomas, three colon cancers, two gall bladder cancers, two esophageal cancers, and one hepatoma. When the survival fraction observed in drug combination was smaller than the multiplication of each survival fraction observed in each drug alone, the combined effects were considered to be synergistic. Twenty-two of 33 tumors (gastric cancer 11/16, breast cancer 5/5, liposarcoma 2/4, colon cancer 1/3, gall bladder cancer 2/2, esophageal cancer 1/2, and hepatoma 0/1) formed adequate colony numbers for the evaluation of combined drug effects. Synergistic effects were observed in seven tumors (three gastric cancers, one breast cancer, one gall bladder cancer, one liposarcoma and one esophageal cancer), although three tumors (one gastric cancer, one gall bladder cancer, and one colon cancer) exhibited antagonistic effects.

Cell Division↗
PubMed1986

Role of phospholipids in activation of mitochondrial D(-)-beta-hydroxybutyrate dehydrogenase.

Although phosphatidylcholine (PC) has been shown to be the type of phospholipid required for activation of mitochondrial beta-hydroxybutyrate dehydrogenase (BDH), mixtures of phospholipids containing PC are more effective activators. This study shows that apo-BDH, purified from bovine-heart mitochondria, and phospholipid-reconstituted BDH appear to be polydisperse. Upon cross-linking with dimethylpimelimidate and acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS), the enzyme exhibited molecular weight forms from monomeric to heptameric BDH as well as higher molecular weight aggregates that did not much penetrate the gels. When different phospholipid mixtures containing PC were used to activate apo-BDH, and the reconstituted samples were subjected to cross-linking and SDS-gel electrophoresis, a direct relationship was found between the activating effect of the phospholipids used and BDH monomer concentration in the gels. The effectiveness order of phospholipids used was as follows: a mixture of PC, phosphatidylethanolamine and diphosphatidylglycerol in a molar ratio of 5:4:1 greater than bovine-heart mitochondrial phospholipids greater than Asolectin greater than PC. These results suggest the following. In addition to PC, which is required by BDH, other types of phospholipids play a role in activation of purified apo-BDH, possibly via enzyme disaggregation. The activity exhibited by purified, phospholipid-reconstituted BDH is associated mainly with the lower molecular aggregates of the enzyme, especially monomeric BDH.

Animals↗
PubMed1986

[Clinical studies on a rapid screening assay for anticancer agents with nude mice and isotopic evaluation].

A rapid method using nude mice has been established as an in vivo model for assessing the chemosensitivity of individual human tumors, in which the final evaluation is made with 3H-thymidine (3H-TdR) incorporation into the treated tumor. In 234 of 289 cancers, the chemosensitivity of anticancer agents was evaluated by this method. This assay proved to be feasible in a sufficiently high percentage of human primary tumors (81.0%). The rate of positive sensitivity against all tumors was 23.8% for MMC, 12.3% for 5-FU, 29.1% for CPM and 23.5% for ADM, respectively. The sensitivity of anticancer agents varied according to the type of cancer. Correlation between the sensitivity test and the end results after chemotherapy in cases of inoperable gastrointestinal cancers was investigated, prospectively. Out of 19 cases, the 50% survival time of 11 patients treated with sensitive agents was longer than that of 8 patients treated with insensitive agents. From a prospective-correlative study carried out on 25 patients, this assay appeared to be correlated with clinical response (overall agreement, 76.0%) with specific agreements of sensitivity and resistance of 37.5% and 94.1%, respectively. From these results, it seems reasonable to conclude that this sensitivity test using a human/nude mouse system is a useful screening assay for revealing appropriate agents for the treatment of patients with cancer.

Animals↗