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Biomedical subjects

J Mochizuki

Publications and source records attributed to J Mochizuki.

At least 19 recordsLinked to original sources
PubMed1995

[Study on human eye movements induced by prolonged eye closure and lid opening--report 2. Closing and opening of eyelids].

The eye movement during prolonged eye closure and the following eye opening has not been studied precisely. In the present study we evaluated the eye movement during prolonged eye closure and the following eye opening using a magnetic search oil method. In a bright room, the exact moment of recognizing a visual target during eye opening could not be determined. Therefore, other conditions were used to elucidate the precise relationship between the presence and lack of visual input during eye opening. Eye movement during eye opening was accomplished in three phases. The first phase had rapid movements like visually guided saccades toward the imaged target. The second phase had slow movements and drift toward the imaged target, and the final eye position was reached within 3 degrees from the target from 5 different gaze directions. The third phase was final visually evoked corrective saccades and the subjects found the target. We discuss the origin of these eye movements.

Adult↗
PubMed1995

[Study on human eye movements induced by blinks--report 1. Three kinds of blinking].

The eye movement associated with blinking was studied with a magnetic search coil method. Lid movements and eye movements associated with spontaneous blinks, voluntary blinks, and reflex blinks induced by puffs of air or flashes of light were analysed. Eye movements associated with spontaneous blinks and voluntary blinks had initial downward and adducted movements followed by upward and abducted movements of the eyeball. Reflex blinks initially showed the same downward and adducted movements, but upward and abducted movements were not constantly obtained in given subjects. The velocity-amplitude ratio was equal among the three kinds of blinks in both horizontal and vertical movements. The velocity-amplitude ratio of the eye movements associated with blinks and visually-guided saccadic eye movements was compared. The horizontal and vertical eye movements associated with blinks were slower than those of saccadic eye movements in the same subject. Therefore, the eye movements associated with the blinks may have a different neural mechanism in the brain from that of the saccadic eye movement system.

Adult↗
PubMed1994

Antitumor activity of SPM VIII, a derivative of the nucleoside antibiotic spicamycin, against human tumor xenografts.

The antitumor activity of spicamycin analogue SPM VIII against human stomach, breast, lung, colon and esophageal cancers was compared to that of mitomycin C (MMC) in the human tumor-nude mice xenograft model. Comparative studies of SPM VIII given i.v. at 6 mg/kg/day daily for 5 days and MMC given i.v. at 6.7 mg/kg on day 1 revealed that the antitumor spectrum of SPM VIII showed a different pattern from that of MMC and that SPM VIII caused tumor mass reductions in more tumors than did MMC in colon cancers (4/12 versus 1/11). In addition to this study, a comparative study of SPM VIII given i.v. at 12 mg/kg/day 8 times at 3- or 4-day intervals and 5'-deoxy-5-fluorouridine (5'-DFUR) given po at 185 mg/kg/day 5 days per week for 4 weeks showed that SPM VIII had the highest effect on SC-9 human stomach cancer and COL-1 human colon cancer among the 3 compounds, resulting in a significant reduction of tumor mass. Although other pharmacological studies are in progress, these results suggest that SPM VIII might be a novel antitumor compound effective for human cancers including cancer of the digestive organs.

Animals↗
PubMed1994

Antitumor activity of a spicamycin derivative, KRN5500, and its active metabolite in tumor cells.

KRN5500, (6-[4-Deoxy-4-(2E,4E)-tetradecadienoylglycyl]amino-L-glycero - beta-L-mannoheptopyranosyl]amino-9H-purine), was semi-synthesized in an attempt to increase the therapeutic effects of spicamycin analogues. The present study evaluated the antitumor activity of KRN5500 against murine tumors and human tumor xenografts. KRN5500 prolonged the survival of P388 leukemia- and B16 melanoma-bearing mice but was marginally effective on colon adenocarcinoma 26. The antitumor activity of KRN5500 (4 mg/kg/day x 5, IV) against xenografts of 10 human stomach, 14 colon and 2 esophageal cancers was evaluated with two parameters: the tumor growth inhibition rate (TGIR) and the tumor mass reduction by comparison with mitomycin C (MMC, 6.7 mg/kg/day x 1,IV). KRN5500 showed a marked efficacy in the human tumor xenograft model. The overall response rate of 26 cancers to KRN5500, evaluated by TGIR, was approximately equal to their response rate to MMC (72% vs. 73%). However, more tumors were reduced by KRN5500 than by MMC (52% vs. 39%). It is notable that the response rates of 14 colon cancers to KRN5500 were significantly higher than those to MMC, both in TGIR (69% vs. 58%) and in tumor mass reduction (46% vs. 23%). Among the tumors sensitive to KRN5500, COL-1 showed a marked response (TGIR 93%) and a significant reduction in tumor mass (0.22-fold the starting volume). In the mode of action, KRN5500 was found to show an inhibitory effect on protein synthesis in P388 cells (IC50 1.5 microM). However, KRN5500 was ineffective even at 170 microM in inhibition of protein synthesis in rabbit reticulocyte lysates.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Structure-antitumor activity relationship of semi-synthetic spicamycin analogues.

Spicamycin, a nucleoside antibiotic containing fatty acids with a variety of chain lengths (C12-C18), showed potent antitumor activity against human gastric cancer SC-9 and human breast cancer MX-1 in a xenograft model. We have made several semi-synthetic spicamycin analogues (SPMs) which differed in the chain length of the fatty acid moiety, and examined their structure-antitumor activity relationship. The cytotoxic activities of SPMs depended on the chain length of the fatty acid moiety, with dodecanoyl, tetradecanoyl, hexadecanoyl and icosanoyl analogues (SPM VIII, SPM X, SPM XII and SPM XVI) exhibiting the most potent cytotoxic activity against P388 murine leukemia cells. SPM VIII showed the most activity against SC-9 in the human tumor xenograft model with the highest therapeutic index among SPMs. The antitumor activity of SPM VIII was superior to that of mitomycin C.

Animals↗
PubMed1993

Phenazoviridin, a novel free radical scavenger from Streptomyces sp. Taxonomy, fermentation, isolation, structure elucidation and biological properties.

Phenazoviridin is a newly discovered free radical scavenger from microorganisms. It was isolated from the culture of Streptomyces sp. HR04. The structure of phenazoviridin was determined as 6-(3-methyl-2-butenyl)phenazine-1-carboxylic acid 6-deoxy-alpha-L-talopyranose ester on the basis of its spectroscopic and physico-chemical properties. The novel substance showed strong inhibitory activity against lipid peroxidation in rat brain homogenate and exhibited antihypoxic activity in mice.

Animals↗
PubMed1993

Thiazohalostatin, a new cytoprotective substance produced by Actinomadura. I. Taxonomy, production, isolation and biological activities.

Thiazohalostatin has been isolated from the culture broth of Actinomadura sp. by a screening program designed to find novel cytoprotective substances. It was purified by use of column chromatography on silica gel, reversed phase HPLC and then isolated as colorless powder. Thiazohalostatin prevented cell death caused by calcium overload and exhibited an inhibitory activity against lipid peroxidation.

Actinomycetaceae↗
PubMed1993

In vitro and ex vivo free radical scavenging activities of carazostatin, carbazomycin B and their derivatives.

Free radical scavenging activities of various carbazole compounds, carazostatin, carbazomycin B and their chemically modified derivatives were studied in vitro and ex vivo. Among these compounds, carazostatin, which was isolated as a free radical scavenger from the culture of Streptomyces chromofuscus, showed the most potent inhibitory activity against lipid peroxidation of rat brain homogenate in vitro. Carbazomycin B, a known antimicrobial antibiotic, also exhibited strong activity in this system. Although O-modified derivatives of carazostatin and carbazomycin B retained considerable activity, N,O-dimethyl derivatives did not suppress the peroxidation. On the other hand, the results from the ex vivo evaluation of these carbazoles in the lipid peroxidation system of mouse blood plasma showed that the original compounds as well as their O-modified derivatives had a strong inhibitory activity upon oral administration to mice. These findings suggest that these natural carbazoles and their effective derivatives can protect tissues from the peroxidative damage due to generation of free radicals.

Administration, Oral↗
PubMed1993

Rumbrin, a new cytoprotective substance produced by Auxarthron umbrinum. I. Taxonomy, production, isolation and biological activities.

Rumbrin has been isolated from a fungus, Auxarthron umbrinum, by a screening program designed to find microorganism-produced cytoprotective substances. It was purified by use of column chromatography on silica gel, reversed phase HPLC and then isolated as fine red needles. Rumbrin prevented cell death caused by calcium overload and exhibited a potent inhibitory activity against lipid peroxidation.

Animals↗
PubMed1993

Pyrrolostatin, a novel lipid peroxidation inhibitor from Streptomyces chrestomyceticus. Taxonomy, fermentation, isolation, structure elucidation and biological properties.

Pyrrolostatin, a new lipid peroxidation inhibitor, was isolated from the culture of Streptomyces chrestomyceticus EC40. The structure was determined to be 4-geranylpyrrole-2-carboxylic acid on the basis of its spectroscopic and physico-chemical properties. Pyrrolostatin inhibited lipid peroxidation in rat brain homogenate.

Animals↗