OBJECTIVE: To investigate the effect of the anteroposterior cricoid split on cartilage growth. METHOD: The rabbits were killed 8 months after the surgery of anteroposterior cricoid split. The larynxes were harvested and the cross-sectional area of the cricoid cartilage were calculated. RESULT: There was no significant difference in the cross-sectional area of the cricoid cartilage of these three groups. CONCLUSION The anteroposterior cricoid split might have no adverse effect on subsequent growth of cricoid cartilage.
Animals ; Cricoid Cartilage ; growth & development ; surgery ; Laryngostenosis ; surgery ; Rabbits

BACKGROUNDIn order to improve the clinical treatment level of urinary system injury, it is necessary to build up an animal model of urinary system wound, which is not only analogous to real clinical practice, but also simple and practical.

METHODSWe have developed the third generation of firearm fragment wound generator based on the first and the second producer. The best explosive charge of the blank cartridge was selected by gradient powder loading experiments. The firearm fragment injuries were made to the bulbous urethra of 10 New Zealand male rabbits. One week preoperatively and 2, 4 and 8 weeks postoperatively, all the animals underwent urethroscopy and urethrography. At 2, 4 and 8 weeks postoperatively, two animals were randomly selected and killed, and the urethra was cut off for pathological examination.

RESULTSThe shooting distance of the third generation of firearm fragment wound generator is 2 cm. The best explosive charge of the blank cartridge is 1 g of nitrocotton. All rabbits survived the procedures and stayed alive until they were killed. Injuries were limited to bulbous urethra and distal urethra. Round damaged areas, 1-1.5 cm in length, on the ventral wall were observed. Ureteroscopy results showed that canal diameter gradually shrank by over 50% in 9 rabbits. The rate of success was 90%. Urethrography result noted that a 1-1.3 cm stricture was formed at the bulbous urethra. Histology results of injured stricture urethra showed that fibrous connective tissue hyperplasia and hyaline degeneration caused further stricture in the canal.

CONCLUSIONSThe third generation of firearm fragment wound generator imitates the bullet firing process and is more accurate and repeatable. The corresponding rabbit model of traumatic complex urethral stricture simulates the real complex clinical conditions. This animal model provides a standardized platform for clinical researches on treating traumatic injuries to the urinary system.

Animals ; Disease Models, Animal ; Male ; Penis ; surgery ; Rabbits ; Urethra ; surgery ; Urethral Stricture ; surgery

PURPOSE: To investigate the effects of varying the time of Mitomycin-C (MMC) subconjunctival injection before, during and after operation. METHOD: We divided rabbits into 3 groups according to injection time. Subconjunctival injections of 0.01% MMC 0.05 ml were given to the preoperative group at 6, 12 and 24 hours before operation, and to the postoperative group at 6, 12 and 24 hours after operation. The control group was given the injections during operation. Bleb formation and histologic analyses were studied for 4 weeks after operation. RESULTS For gross findings, the blebs of the preoperative and control groups were seen on the fourth day and completely formed at one week after operation, and were larger than those of the postoperative group. On the other hand, the blebs of the postoperative group were seen to have poor formation, displaying hypervascularity on the fourth day and disappearing one week after operation. For histologic findings, the proliferation of collagen fibers and the undifferentiation of fibroblasts observed in the preoperative and control groups were almost identical. But, the proliferation of collagen fibers and well-differentiated fibroblasts were seen to increase in the postoperative group, so aqueous flow was obstructed at week 3. CONCLUSIONS: Subconjunctival injections within 24 hours before or during glaucoma filtration surgery were better for bleb formation and preservation than those administerd after surgery.
Blister ; Collagen ; Fibroblasts ; Filtering Surgery* ; Filtration* ; Glaucoma* ; Hand ; Mitomycin* ; Rabbits*

PURPOSE: To investigate the effects of varying the time of Mitomycin-C (MMC) subconjunctival injection before, during and after operation. METHOD: We divided rabbits into 3 groups according to injection time. Subconjunctival injections of 0.01% MMC 0.05 ml were given to the preoperative group at 6, 12 and 24 hours before operation, and to the postoperative group at 6, 12 and 24 hours after operation. The control group was given the injections during operation. Bleb formation and histologic analyses were studied for 4 weeks after operation. RESULTS For gross findings, the blebs of the preoperative and control groups were seen on the fourth day and completely formed at one week after operation, and were larger than those of the postoperative group. On the other hand, the blebs of the postoperative group were seen to have poor formation, displaying hypervascularity on the fourth day and disappearing one week after operation. For histologic findings, the proliferation of collagen fibers and the undifferentiation of fibroblasts observed in the preoperative and control groups were almost identical. But, the proliferation of collagen fibers and well-differentiated fibroblasts were seen to increase in the postoperative group, so aqueous flow was obstructed at week 3. CONCLUSIONS: Subconjunctival injections within 24 hours before or during glaucoma filtration surgery were better for bleb formation and preservation than those administerd after surgery.
Blister ; Collagen ; Fibroblasts ; Filtering Surgery* ; Filtration* ; Glaucoma* ; Hand ; Mitomycin* ; Rabbits*

We investigated the long-term scleral toxicity after single intraoperative exposure to mitomycin-C(MMC) at 2 different exposure length of time and with or without profuse irrigation after the MMC applications during glaucoma filtering surgery(GFS) in rabbit eyes. Albino rabbits undergoing GFS received a single exposure to MMC 0.5 mg/ml for 1 or 5 minutes with placing MMC-soaked sponges between the conjunctival flap and the scleral bed. A subsequent irrigation of the exposed tissue with 250 ml of balanced salt solution(BSS) was done in one group but not in the other groups. Six months after GFS, the eyes were enucleated and fixed in glutaraldehyde for transmission electron microscopy(TEM). TEM revealed degenerative changes of the fibroblasts at the middle portion of sclera in all MMC treated groups. There were some differences between the groups with 1 minute and 5 minutes exposure to MMC. No discernible differences existed in the ultrastructural findings of the scleral fibroblasts between the groups with or without BSS irrgation after 5-minutes exposure to MMC. Our observation suggest that an exposure to MMC 0.5 mg/ml can cause longterm scleral fibroblast toxicity. There was no discernible differences in scleral fibroblast toxicity between the groups with and without profuse BSS irrigation.
Fibroblasts* ; Filtering Surgery* ; Glaucoma* ; Glutaral ; Mitomycin* ; Porifera ; Rabbits ; Sclera

In glaucoma filtering surgery, we conducted subconjunctival injection of Mitomycin-C(MMC) 12 hours before and after surgery, and examined histologic findings of the filtering bleb, and condition of the anterior chamber which ensued after the injection. We divided 15 full-grown rabbits into three groups, and for each group, administered subconjunctivally 0.1cc of 0.002%, 0.004%, and 0.008% MMC, respectively. The subconjunctival injection of MMC before surgery was given to the right eye and post-surgical injection to the left, and we examined the results 1, 2, 4, 7, and 14 days after the administration.In conclusion, subconjunctival injection of MMC 12 hours before glaucoma filtering surgery is shown to be more effective than the injection after the surgery.
Anterior Chamber ; Blister* ; Filtering Surgery* ; Glaucoma* ; Mitomycin* ; Rabbits

The study was carried out to investigate the efficacy of subconjunctivally injected mitomycin-C (MMC) on glaucoma filtration surgery(GFS) in rabbit eyes. Each of 0.05mg, 0.1mg and 0.2mg MMC were injected subconjunctivally into the rabbit eye according to groups I, II, III respectively following GFS. The IOP were returned to preoperative level at postoperative 2 weeks in control group, and at postoperative 12 weeks in group I and II. Histologically the fibrotic reaction appears less intensively in the order of group III, II, I and control group at 2 weeks after GFS. At postoperative 12th week, fibroblasts are more frequently oberved in group I and II than control group. But the proliferation of collagenous and reticulin fibers are less in group I and II than control group. The least amount of fibroblasts, collagenous and reticulin fibers are found in group III. It is suggested that subconjunctival injection of lower concentration of MMC would be effective approval as an adjunctive method to improve more success rate of GFS from this study.
Collagen ; Fibroblasts ; Filtering Surgery* ; Filtration* ; Glaucoma* ; Mitomycin* ; Rabbits* ; Reticulin

We compared the effect of topical minoxidil after filtering surgery with that of mitomycin C (MMC) application in rabbits. Fourty-nine eyes were divided into the minoxidil-treated eyes, MMC_treated eyes and control eyes. Intraocular pressure (IOP) in minoxidil-treated eyes and MMC-soaked eyes were significantly lower than that of the control eyes at postoperative 1 and 3 days. MMC-soaked eyes had lower IOPs than the minoxidil-treated and control eyes, but IOPs in the minoxidil- and control eyes were similar at days 5 to 21. IOP survival in the MMC-treated eyes was significantly longer than in both the minoxidil-treated and control eyes. These results suggest that topical minoxidil can cause reduction of IOP at the early postoperative period. Howver, the IOP lowering effect of Minoxidil did not last as long as that of MMC soaking. Further study is necessary to enhance the efect of topical minoxidil including its method of application and optimal concentration.
Filtering Surgery ; Glaucoma* ; Intraocular Pressure ; Minoxidil* ; Mitomycin* ; Postoperative Period ; Rabbits*

PURPOSE: We investigated the anti-inflammatory and anti-fibrotic effects of amniotic membrane(AM) ointment in filtering surgery of rabbits. METHODS: After filtering surgery was performed on both eyes of 10 rabbits, the AM ointment was applied over and under the scleral flap on one eye whereas base ointment excluding AM element was applied to the other as a control. The shapes of blebs were observed under slit-lamp biomicroscopy at postoperative 3 days, 1 week, 2 weeks and 4 weeks, and the tissues were excised for histologic studies. RESULTS: Serial changes of intraocular pressures had no significant difference. Slit-lamp biomicroscopy demonstrated that conjunctival blebs of AM ointment group were more elevated and cystic at 1 and 2 weeks. The heights of conjunctival blebs were significantly higher at 1, 2 and 4 weeks, and the width of scleral tracks was significantly wider at 1 and 2 weeks in AM ointment group. The number of inflammatory cells in the scleral track was significantly less at 3 days and 1 week, the number of fibroblasts in scleral track was significantly less at 2 and 3 weeks in AM ointment group. Masson s trichrome stain was less positive in AM ointment and the stain area of alpha-smooth muscle actin-positive fibroblasts was insignificant with image analysis system. Collagen type 3 appeared in scleral track from postoperative 1 week in control group, however, in AM ointment group, from 4 weeks. CONCLUSIONS: AM ointment is beneficial to suppress fibroblast differentiation, proliferation and inflam-matory reaction in filtering surgery and might be safe and effective adjunctive for enhancement of success in filtering surgery.
Amnion* ; Blister ; Collagen ; Fibroblasts ; Filtering Surgery* ; Humans* ; Intraocular Pressure ; Rabbits*

BACKGROUND: The aim of the present study was to prepare hydroxyapatite (HA) and then characterize its effect on bone integration in a rabbit tibial defect model. The bone formation with different designs of HA was compared and the bony integration of several graft materials was investigated qualitatively by radiologic and histologic study. METHODS: Ten rabbits were included in this study; two holes were drilled bilaterally across the near cortex and the four holes in each rabbit were divided into four treatment groups (HAP, hydroxyapatite powder; HAC, hydroxyapatite cylinder; HA/TCP, hydroxyapatite/tri-calcium phosphate cylinder, and titanium cylinder). The volume of bone ingrowth and the change of bone mineral density were statistically calculated by computed tomography five times for each treatment group at 0, 2, 4, 6, and 8 weeks after grafting. Histologic analysis was performed at 8 weeks after grafting. RESULTS: The HAP group showed the most pronounced effect on the bone ingrowth surface area, which seen at 4, 6, and 8 weeks after graft (p < 0.05). On comparing the change of bone mineral density the bone ingrowth surface area among the 4 groups, there were no statistically significant differences among the groups found for any period (p > 0.05). On histological examination, the HAP group revealed well-recovered cortical bone, but the bone was irregularly thickened and haphazardly admixed with powder. The HAC group showed similar histological features to those of the HA/TCP group; the cortical surface of the newly developed bone was smooth and the bone matrix on the surface of the cylinder was regularly arranged. CONCLUSIONS: We concluded that both the hydroxyapatite powder and cylinder models investigated in our study may be suitable as a bone substitute in the rabbit tibial defect model, but their characteristic properties are quite different. In contrast to hydroxyapatite powder, which showed better results for the bone ingrowth surface, the hydroxyapatite cylinder showed better results for the sustained morphology.
Animals ; *Bone Substitutes ; *Durapatite ; *Osseointegration ; Rabbits ; Tibia/pathology/radiography/*surgery