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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

As the UV-B cataract and early stages of diabetic cataract in rats only touches the epithelium and anterior superficial cortex, a whole lens analysis is not meaningful, but a regional analysis with the freeze-sectioning device has to be performed. Scheimpflug photography with microdensitometric image analysis enables the scientist to discern in vivo single layers along the optical axis of the lens. UV-B cataracts (0.2 J/cm2, every 2nd day) and diabetic cataracts (Streptozotocin (STZ), 70 mg/kg BW) were induced in Brown-Norway rats. The stages of lens opacification were documented by Scheimpflug photography. 8 weeks after start of UV-B treatment and at several dates before onset of visible diabetic cataractous changes, the animals were sacrificed. The lenses were divided reproducibly into 4 or 7 parts such as an equatorial ring and several layers of the central cylinder from anterior to posterior part. The enzyme activity spectrum shows highly region related pattern that would not have been found in a whole lens analysis. Aldose reductase was activated before appearance of visible cataractous changes due to diabetes compared to normal lenses. In contrast Fructose-1,6-biphosphate-aldolase activity was lower before onset of visible changes than in normal lenses, but only within the 1st section where later visible cataractous changes of UV-B cataract could be detected.
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PMID:Regional enzymatic analysis of UV-B and streptozotocin induced diabetic cataract lens. 196 39

Scheimpflug photography has become the basic method for documentation of lens transparency changes in clinical and experimental ophthalmology, due to its high reproducibility. In animal cataract studies, the reproducibility is strongly influenced by the handling characteristics of the camera used, due to limited cooperation of the animal. The reproducibility of the Zeiss SLC system, which offers a direct quality control of the image on the video screen, was tested with 2 animal cataract models, the ultraviolet B (UVB)-induced cataract and the true diabetic cataract in the Brown-Norway rat. 10 rats each of the 2 cataract models and of an untreated control group were photographed in a random order on 3 occasions on the same day by the same photographer. Quality control and densitometry were performed by the same system operator, the measurement window was positioned standardly, coincident with the optical axis of the eye. Statistical comparison was carried out in the capsular layer, that is the area of initial cataract development in both models, and in the cortical layer, into which the diabetic cataract progresses during its later stages of development. The nuclear layer was also evaluated, but has no direct relation to one of the models employed. The results clearly indicate that the reproducibility is predominantly influenced by the homogeneity or inhomogeneity of the cataract model employed. The system operator and the photographer provided that they are well trained, have minor influence on the reproducibility of the Zeiss SLC system.
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PMID:Reproducibility studies with the Zeiss SLC system and animal cataract models. 238 45

Development of experimental cataract can be objectively monitored in rats by application of Scheimpflug photography with the SL 45 Topcon camera and subsequent densitometric image analysis. The method has been used to study naphthalene cataract in Brown-Norway rats (BN-CPB), as well as diabetic cataract induced by streptozotocin injection in Sprague-Dawley rats. The values obtained by linear microdensitometric image analysis allowed precise characterization of the opacification with respect to size, topography, and time progress so that statistical evaluation of the efficacy of certain drugs in prevention or delay of experimental cataracts was possible.
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PMID:Long-term follow-up examination of experimental cataracts in rats by Scheimpflug photography and densitometry. 651 Jul 20

In order to find an appropriate model of experimentally induced streptozotocin diabetic cataract rat for evaluation of the anti-cataract agents. Experimental diabetic cataracts were induced in 3 rat strains (Sprague-Dawley SD, Brown Norway BN, Wistar WIS), age 5 and 7 weeks old, by intravenous injection of 70 mg/kg streptozotocin. The cataract progression was followed by morphological and biochemical assessment. Two types of initial cataractous change were observed in SD and WIS rats which mainly consisted of water-vacuole formation in the peripheral area and a diffuse cloudiness progressing around the anterior Y-suture area. The initial change of BN rats was a Y-suture dissociation and fine water-clefts with dot-like vacuoles. Those initial changes in SD and WIS rats differed from those in BN. No difference in aldose reductase activities among the three strains was found, but BN rats had significantly higher sorbitol dehydrogenase activity than SD or WIS rats. It seems that 7-week-old BN rats are more suitable for experimental diabetic cataract models than SD or WIS.
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PMID:[Reinvestigation of streptozotocin induced diabetic cataract as a standard experimental model]. 831 49