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Biomedical subjects

B Lundgren

Publications and source records attributed to B Lundgren.

159 records · Page 9Linked to original sources

After-cataract formation in newborn rabbits implanted with intraocular lenses.

PURPOSE: Comparison of the after-cataract formation in newborn rabbits implanted with a heparin-surface-modified (HSM) intraocular lens (IOL), a silicone IOL, or no IOL. METHODS: Two groups of 3-week-old rabbits were used. In Group 1 (n = 11), lensectomy was performed in both eyes. One eye was selected at random and an HSM IOL was implanted in the capsular bag; the other eye was left aphakic. In Group 2 (n = 13), lensectomy was performed in both eyes. An HSM IOL was implanted in one eye, a silicone IOL in the other. The wet mass of the dissected after-cataract was determined 3 months after surgery in both groups. RESULTS: In Group 1, the wet mass of the dissected after-cataract was 17.0 +/- 6.5 mg (mean +/- SEM) in eyes implanted with an HSM IOL and 159.7 +/- 17.0 mg in aphakic eyes. This difference was statistically significant (P < .01). In Group 2, the wet mass of the dissected after-cataract was 18.3 +/- 4.3 mg in eyes implanted with an HSM IOL and 25.7 +/- 5.2 mg in eyes implanted with a silicone IOL. No statistically significant difference was found. CONCLUSIONS: In young rabbits, implantation of an IOL in the capsular bag following lensectomy reduced cell proliferation.

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Inflammatory response in the rabbit after phacoemulsification and intraocular lens implantation using a 5.2 or 11.0 mm incision.

PURPOSE: To study the effect of two incision sizes, 5.2 and 11.0 mm, on the inflammatory response in rabbit eyes after lens extraction with phacoemulsification. SETTING: S:t Erik's Eye Hospital, Stockholm, and Pharmacia, Uppsala, Sweden. METHODS: Bilateral endocapsular phacoemulsification was performed on 32 rabbits. The wound was enlarged to 5.2 mm, and a poly(methyl methacrylate) intraocular lens (IOL) was implanted in the capsular bag. In each rabbit, one eye was selected at random and the wound in that eye enlarged to 11.0 mm. In both eyes the wound was sutured with a 9-0 polypropylene continuous suture. The number of white blood cells (WBCs) and prostaglandin E2 (PGE2) in the aqueous humor were measured at days 1, 3, 7, and 28 postoperatively. Corneal thickness was also measured by pachymetry. RESULTS: The number of WBCs at day 3 and the PGE2 levels at days 1, 3, and 7 were significantly higher in eyes with 11.0 mm incisions than in eyes with 5.2 mm incisions. One week after surgery, the corneas in the eyes with 11.0 mm incisions were significantly thicker than in those with 5.2 mm incisions. CONCLUSION: The results indicate that incision size is an important factor in the inflammatory response following phacoemulsification and IOL implantation in the rabbit eye.

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Cultured rat and purified human Pneumocystis carinii stimulate intra- but not extracellular free radical production in human neutrophils.

The production of free radicals in human neutrophils was studied in both Pneumocystis carinii derived from cultures of L2 rat lung epithelial-like cells and Pneumocystis carinii purified from human lung. Using the cytochrome C technique, which selectively measured extracellular superoxide generation, hardly any free radical production was observed after stimulation with cultured rat-derived P. carinii. A chemiluminescence technique, which separately measured intra- and extracellular free radical production, was subsequently employed to differentiate the free radical generation. It was established that 1) P. carinii stimulated intra- but not extracellular free radical production in human neutrophils, 2) opsonized cultured rat-derived P. carinii stimulated human neutrophils to a strong intracellular response of superoxide production, and 3) opsonized P. carinii, purified from human lung also stimulated human neutrophils to produce intracellular free radicals.

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Development of posterior capsule opacification in the rabbit.

PURPOSE: The aim of the present study was to characterize the development of after-cataract in the rabbit by measuring its wet weight, protein, DNA and glycosaminoglycan (GAG) contents and using Scheimpflug and slitlamp analysis. Further, aqueous humor (AqH) leukocytes, protein and lens epithelial cell proliferation activity were determined. METHODS: AqH was collected and capsular bags including after-cataract were dissected free on days 0, 1, 7, 14, 28 and 56 after cataract surgery. The wet weights were determined and the contents of DNA, protein and GAG in the capsular bags including after-cataract were analyzed. AqH was analyzed for leukocytes, protein and proliferative activity. In another set of experiments, rabbit eyes were analyzed by the Scheimpflug technique and slitlamp examination on days 0, 1, 7, 14, 28 and 56 after cataract surgery. The wet weight of the capsular bag with the after-cataract was also determined. RESULTS: An increase was found in the wet weight (480%) and the contents of protein (221%), DNA (945%) and GAG (336%) of the capsular bags including after-cataract during the experimental period. In the AqH, all 3 variables measured, leukocytes, protein and proliferative activity, reached their highest levels on day 1 after surgery. In the second set of experiments, the wet weight of the capsular bag including after-cataract increased by 391% during the 56-day experimental period. Posterior capsule opacification (PCO), as measured by Scheimpflug analysis, increased from 0.8 to 81.7% and the scores of Elschnig's pearls as well as fibrosis, analyzed by slitlamp, increased from 0.0 to 2.8 and 3.0, respectively. CONCLUSIONS: This study shows that the same components that are reported to be important in human PCO are also components of PCO in the rabbit. Thus, the rabbit model seems to accurately reflect human PCO development, and because PCO develops much faster in rabbits that would make the rabbit model suitable for studies to elucidate human PCO development.

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Characterization of the induction of cytosolic and microsomal epoxide hydrolases by 2-ethylhexanoic acid in mouse liver.

When mice were exposed to 1% 2-ethylhexanoic acid in the diet, cytosolic and microsomal epoxide hydrolase (EC 3.3.2.3) activities were increased maximally (2-2.5- and 0.5-1-fold, respectively) after 3 days. Immunochemical quantitation of these enzymes indicated that the process involved was a true induction in both cases. Maximal levels of peroxisome proliferation (as indicated by carnitine acetyltransferase activity) were obtained after 7 days of exposure. All three of these activities returned to control levels within 4 days after termination of the treatment. The liver somatic index was slightly increased after 4 days of administration of 1% 2-ethylhexanoic acid, but the protein contents of the "mitochondrial," microsomal, and cytosolic fractions were unaffected. The activity of peroxisomal palmitoyl-CoA beta-oxidation was increased 2-fold, whereas peroxisomal catalase activity was unaffected. Exposure to 2-ethylhexanoic acid also increased cytochrome oxidase activity, suggesting an effect on mitochondria. Other parameters of detoxication--i.e. total microsomal cytochrome P-450 content, cytosolic glutathione transferase activity toward 1-chloro-2,4-dinitrobenzene, and the "cytosolic" epoxide hydrolase activity localized in the "mitochondrial" fraction--were not affected by 4 days of treatment with 1% 2-ethylhexanoic acid.

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Pneumocystis carinii from pigs and humans are antigenically distinct.

The antigens of Pneumocystis carinii cysts isolated from pigs and humans were compared by the Western immunoblotting technique. Convalescent pig serum reacted with two antigens (approximately 78 kDa and 32.5 kDa) of porcine P. carinii cysts, whereas convalescent serum from humans did not react with porcine P. carinii cyst antigens. The results indicate that porcine and human P. carinii cysts are antigenically distinct.

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