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Biomedical subjects

K Muta

Publications and source records attributed to K Muta.

94 records · Page 6Linked to original sources

Hepatic tumors of rabbits induced by cycad extract.

Fifteen rabbits were administered cycad extract by gastric intubation, 1 ml/rabbit, once a week for 27 or 33 weeks. The extract contained 16.6 mg of cycasin/ml. Out of 9 rabbits surviving over 200 days, 7 animals had malignant neoplasms developing in the liver. Histological and electron microscopic examinations of the developed tumors revealed that they were malignant hemangioendotheliomas. The animals showed no proliferation of hepatic cells or any tumor development in other organs.

Animals↗

Intestinal tumors of rats by gastric or intestinal administration of cycad extract and cycasin.

Sprague-Dawley rats were given gastric intubation of cycad extract (group 1), rectal infusion of cycasin (group 2), or rectal indusion of cycad extract after external colostomy at 1/3 proximal portion of the large intestine (group 3). In group 1, intestinal tumors developed in any portion of the intestinal tract ranging from the duodenum to the rectum. In group 2, tumors developed in mucosa of the large intestine. In group 3, however, tumors arose from both sites of intestinal mucosa which were in contact and not in contact directly with the cycad extract infused. Possible hypothesis for intestinal tumor development by cycad extract and cycasin was presented.

Adenocarcinoma↗

Effect of topical carteolol on iridial circulation in pigmented rabbit eyes.

The effect of a single instillation of topical carteolol on iridial tissue circulation of pigmented rabbits was studied. The blood flow rate and a quantitative index of tissue blood velocity (NBiris) were measured simultaneously, using the microsphere technique and the laser speckle method, before and 2 hours after the instillation of 20 microliters of 2% carteolol or the vehicle. Consecutive changes of intraocular pressure and NBiris were also studied at 30-minute intervals for 2.5 hours after a single instillation of 2% carteolol in one eye and the vehicle in the contralateral eye. To provide a control, intraocular pressure and NBiris were measured according to the same schedule after the vehicle instillation in both eyes. Two hours after carteolol instillation, iridial blood flow rate and NBiris significantly increased to 127 +/- 8% and 122 +/- 9% (mean +/- SEM, n = 8) of the baseline. Unilateral instillation of carteolol significantly reduced intraocular pressure by about 9 mm Hg in both the carteolol- and vehicle-treated eyes (P < 0.001, analysis of variance); and NBiris was significantly increased by about 20% in both eyes (P < 0.001, analysis of variance), compared with control eyes.

Administration, Topical↗

Effect of topical dorzolamide on tissue circulation in the rabbit optic nerve head.

PURPOSE: To examine the effect of 1% topical dorzolamide on tissue circulation in the optic nerve head (ONH) of Dutch rabbits. METHODS: A laser speckle tissue circulation analyzer was used. One eye of each rabbit received 1% topical dorzolamide twice daily for 20 days, and the fellow eye received the vehicle in a masked, randomized manner. Intraocular pressure (IOP) was measured every 5 days. The normalized blur (NB) value, a quantitative index of tissue blood flow velocity in the ONH, was measured before treatment and 2 hours after the last instillation on the 20th day. RESULTS: The IOP was lowered by about 2 mm Hg only in the dorzolamide-treated eyes (P < .01). The NB value showed no significant change in either dorzolamide-treated or vehicle-treated eyes. CONCLUSIONS: Long-term topical dorzolamide does not affect the ONH tissue circulation in dorzolamide- and vehicle-treated eyes of Dutch rabbits.

Animals↗