No abstract available.
Rabbits*

No abstract available.
Rabbits*

No abstract available.
Rabbits*

No abstract available.
Rabbits*

No abstract available.
Rabbits*

To understand the mechanism of cell injury when exposed to HgCl2, monitoring of cytosolic ionized free Ca2+([Ca2+]i), viability test, measurement of the amount of ATP, and Ca-ATPase activity were evaluated in cultured rabbit renal tubular cells(RTC) exposed to HgCl2. The results were as follows: 1) HgCl2 was cytotoxic to rabbit RTC at all doses except 10 uM and the rate of killing displayed a dose- and time-dependent relationship. 2) The absence of extracellular Ca provided partial protection from irreversible injury induced by HgCl2. 3) The increasing pattem of [Ca2+]i varied according to the concentrations of HgCl2. At the low concentrations of HgCl2 (2.5-10 microM), the level of [Ca2+]i increased slowly over the flat 2-3 min and then achieved plateau-state. In contrast, at the high concentrations of HgCl2 (25-100 microM) the level of [Ca2+]i achieved peak within 1 min and then decreased to a plateau state under normal concentrations. 4) The level of ATP was decreased to 27.5% of that of normal control cells within 3 min by using a treatment of 100 microM HgCl2. 5) HgCl2 did not affect the Ca2+ ATPase activity by enzyme histochemical observation. These findings suggest that the elevation of [Ca2+]i in response to the HgCl2-induced injury is an important event in accelerating injury that ultimately leads to cell death. But other possibilities such as HgCl2 might have direct deleterious effects on the also should be considered.
Rabbits ; Animals

No abstract available.
Ephedrine* ; Rabbits*

Apraclonidine is a potent alpha-adrenergic agonist that, like clonidine, is relatively selective for alpha-2 receptors. Apraclonidine has been shown to lower intraocular pressure by diminishing aqueous humor formation. The purpose of this study is to know the morphological changes in the ciliary epithelium by apraclonidine against aqueous formation. In group I, two drops of 1% apraclonidine hydrochloride were instilled on the right eye of the pigmented rabbits and the eyes were enucleated on 1,2.6 and 24 hours after instillation to find out the duration of action of the drug and the tissue response. In group II, one drop was instilled twice daily for seven days on the right eye and the eyes were enucleated on 1, 2 and 5 days after cessation of the instillation observing the cumulative effect of the drug and the tissue response. These eyes were studied with electron mIcroscopIc examiation. As a result, widening of cell membranes(basal infoldings) of the non-pigmented epithelium(NPE) were observed. This change was recovered with time, and seems to be the principal morphological changes of apraclonidine against aqueous formation in the ciliary body. In group II, the cellular changes were minimal except for well developed rough endoplasmic reticulum representing resumed secretary function of the cell.
Rabbits ; Animals

Under the postulation that double Ruiz procedure could increase the effect of radial keratotomy(RK), RK combined with horizontal and vertical Ruiz procedure was performed in three groups of 22 rabbit eyes. In the group A of six eyes, RK with vertical Ruiz procedure was performed, and eight weeks later the horizontal Ruiz procedure was added. In the group B of eight eyes, RK with horizontal Ruiz procedure was performed, and four weeks later the vertical Ruiz procedure was added. In the group C of eight eyes, RK with horizontal and vertical Ruiz procedure were performed simultaneously. As a control, in the group D of eight eyes, RK without Ruiz procedure was performed. Changes in keratometry for four weeks and eight weeks postoperatively were analyzed. The results were as follows: 1. At eight weeks postoperatively, mean changes in keratometry were 6.434D, 3.663D, 4.030D and 1.585D in groups A,B,C and D, respectively. 2. Mean changes in keratometry of groups A,B and C were significantly higher than that of group D. 3. Mean change in keratometry of 6.434D in group A was significantly the highest of the three groups in which the double Ruiz procedure was performed. From the above results, it was concluded that the double Ruiz procedure increased the effect of RK and that the procedure was more effective when secondary Ruiz procedure was added eight weeks later.
Rabbits ; Animals

The authors studied the early morphologic changes of peripheral nerve, which is known as relatively radioresistant tissue to the X-ray irradiation, but recently clamied by several clinician through development of neuropathies after radiotherapy of the malignacy. Rabbits were received 1,000 or 2,000 cGy of X-ray on the knee joint areas. Sciatic nerves were extracted out 30 minutes, 1, 2, 4, 24 hours, and 3 and 7 days after irradiation. The morphologic changes were observed by light and electron microscopes. The results were summarized as follows: Light microscopically, only mild edema is noted. Electron microscopically, irregular separation and folding of myelin sheath with spherical body formation are noted. Above features were more prominent at later stages and aggregated nests of fragmented myelin were scattered 16 hours after irradiation. Schwann cell necrosis is noted after 24 hours. But above degenerative changes were scarcely present 7 days after irradiation. There is no remarkable axonal changes. The interstitial tissue revealed swelling and irregularity of surface of endothelial cells, and edema. On the basis of the results, it may be concluded that the peripheral nerve is injured by irradiation in early stages, and the main target of irradiation injury is thought to be myelin sheath and Schwann cells, which would be reversible and could be recovered promptly.
Rabbits ; Animals