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Biomedical subjects

S Dev

Publications and source records attributed to S Dev.

29 records · Page 2Linked to original sources
PubMed1998

Decrease in intraocular pressure after orbital decompression for thyroid orbitopathy.

BACKGROUND: The effect of thyroid orbitopathy on intraocular pressure (IOP) remains controversial. We carried out a study to determine the effect of orbital decompression surgery on the IOP in patients with advanced thyroid orbitopathy. METHODS: The records of 12 consecutive patients (22 eyes) who underwent decompression surgery for severe thyroid orbitopathy between 1985 and 1996 were reviewed. All patients were maintained on essentially the same medications before and after surgery. The IOP readings, obtained by means of applanation tonometry in primary gaze, from the pre- and postoperative visits were recorded, and the net change was calculated. RESULTS: The mean preoperative and postoperative IOP values were 19.8 mm Hg and 16.8 mm Hg respectively, a significant difference (p = 0.008). Seven of eight eyes with an IOP of 21 mm Hg or greater preoperatively had a postoperative IOP less than 21 mm Hg; these eyes showed a mean decrease in IOP of 5.6 mm Hg. The degree of preoperative IOP elevation was found to be a strong predictor of the amount of IOP lowering after surgery (p = 0.014). INTERPRETATION: Our results support the concept that orbital congestion associated with thyroid orbitopathy produces an increase in IOP by elevation of episcleral venous pressure (EVP) and that orbital decompression may reduce the IOP by decreasing EVP. Decompression surgery may obviate the need for more aggressive management of glaucoma in patients with severe thyroid orbitopathy.

Adult↗
PubMed1997

Recombinant hirudin prevents postoperative fibrin formation after experimental cataract surgery.

PURPOSE: The authors studied the effect of a direct acting antithrombin agent, desulfatohirudin variant 1 (Revasc, Ciba-Geigy, Ltd., Basel, Switzerland), on postoperative fibrin formation after cataract surgery in rabbits. METHODS: Phacoemulsification was performed in a masked fashion on 28 eyes of 28 New Zealand white rabbits. Ten control group eyes had lactated Ringer's solution in the infusion and an intracameral injection (approximately 1.5 ml) at the end of the case. Ten group 1 eyes received hirudin 100 micrograms/ml in the infusion and intracameral injection. Eight group 2 eyes had 100 micrograms/ml hirudin in the intracameral injection only. Using slit-lamp examination, all eyes were graded for the amount of fibrin and intraocular hemorrhage in a masked fashion on postoperative day 1. RESULTS: Comparison of the mean postoperative fibrin grade (0-4) in group 1 (mean = 0.3), group 2 (mean = 0.25) and the control group (mean = 3.4) revealed a statistically significant difference between hirudin-treated and control eyes (P = 0.0002 for group 1, P = 0.0005 for group 2). No intraocular hemorrhage was noted in any group. CONCLUSIONS: Recombinant hirudin significantly decreases postoperative fibrin formation in a rabbit cataract extraction model. Intracameral injection of hirudin alone appears to be at least as effective as infusion of hirudin throughout the case. With further study, this agent has potential for use in cataract surgery on patients known to be at high risk for postoperative fibrin formation.

Animals↗
PubMed1997

Malakoplakia and colorectal adenocarcinoma.

We report a case of malakoplakia in association with colonic adenocarcinoma. Tumour-associated malakoplakia in the gastrointestinal tract is a rare finding, generally confined to the colon. It may be locally aggressive, with invasion of pericolic tissues, but is always located adjacent to the tumour. This contrasts with the often more diffuse, multifocal distribution of colonic malakoplakia in association with other pathologies.

Adenocarcinoma↗
PubMed1996

Retinal vein occlusion after trabeculectomy with mitomycin C.

PURPOSE: To evaluate acute retinal vein occlusion as a potential complication of trabeculectomy with mitomycin C in cases of advanced glaucoma. METHODS: The records of three patients who developed retinal vein occlusions immediately after uncomplicated trabeculectomy with mitomycin C were reviewed. RESULTS: All three patients had advanced open-angle glaucoma with total cupping of the optic nerve, severe visual field loss, and evidence of systemic vascular disease. A marked decrease in intraocular pressure was noted in the postoperative period in all of the patients. CONCLUSION: A shift in the lamina cribrosa, associated with the perioperative intraocular pressure change, may have contributed to occlusion of the venous outflow system in these susceptible patients.

Aged↗
PubMed1993

Adult rabbit brain synthesizes retinoic acid.

Tissues of adult rabbit brain were shown to enzymatically oxidize retinol and retinaldehyde to retinoic acid, a potent stimulator of gene expression. Rates of retinoic acid synthesis by the cerebrum, cerebellum, and meninges were comparable to, or exceeded, rates measured with rat liver, an organ known to have a relatively high capacity to synthesize retinoic acid. These results, taken together with previous observations that the adult brain contains retinoic acid-activated transcription factors and cellular retinoid-binding proteins, suggest that retinoids may play an important role in the adult central nervous system.

Animals↗
PubMed1992

Synthesis of retinoic acid from retinol by cultured rabbit Müller cells.

Previous observations have shown that Müller glial cells of the vertebrate retina contain cellular retinoid-binding proteins, that the retina contains retinoic acid, and that cellular retinoic acid-binding protein is present in amacrine neurons (and, in some species, Müller cells) within the retina. These findings led to the suggestion that Müller cells may synthesize retinoic acid and release it for use by other retinal cells. To test this possibility, we cultured Müller cells from adult rabbit retinas, incubated the cultures with radioactive retinol, and identified and quantified the resultant radioactive retinoids by HPLC. Retinaldehyde was rapidly synthesized from retinol, reaching a plateau of 1-2 pmol mg-1 cell protein by 30 min. Retinoic acid initially accumulated more slowly, but by 30 min constituted most of the synthesized retinoid. While the retinaldehyde remained within the cells, retinoic acid was rapidly released into the medium; extracellular retinoic acid exceeded the intracellular amount after 30 min of incubation. Smaller amounts of retinyl esters were also synthesized and retained by the cells. These results are consistent with the suggestion that Müller glia are a source of retinoic acid in the retina. The synthesis of retinoic acid by these cells, and the presence of retinal neurons that contain cellular retinoic acid-binding protein, raise the possibility that retinoic acid plays a role in the retina, although this role is not presently known. Furthermore, these results may have implications for other parts of the adult nervous system. Adult brain contains retinol- and retinoic acid-binding proteins, and, therefore, may also be a site of retinoic acid metabolism. Because of the relatively simple cellular organization of the retina and its demonstrated capacity to synthesize retinoic acid, the retina may be a system of choice for further studies of the synthesis and function of retinoic acid in adult neural tissue.

Animals↗
PubMed1989

Isoenzyme biotypes of Candida species.

Isoenzyme profiles were obtained following polyacrylamide gel electrophoresis of crude extracts of Candida albicans and C. tropicalis. The two species were separated by distinct isoenzyme patterns. Within each species, variations were found for several isoenzymes. This allowed the development of a method for biotyping these fungi. Isoenzyme patterns of the sucrose-negative variants "C. stellatoidea" and "C. paratropicalis Baker, Salkin, Pincus, and D'Amato" were obtained and subjected to cluster analysis. This procedure failed to place the variants into clusters that were clearly distinct from the conventional sucrose-positive strains. All sucrose-negative strains were found to have alpha-glucosidase activity. There was an almost complete lack of heterogeneity in the isoenzyme patterns of 11 C. stellatoidea type I strains.

Alkaline Phosphatase↗
PubMedDate not supplied

Fracture toughness ov conventional or photopolymerized glass ionomer/dentin interfaces.

Several new light-cured glass-ionomer materials have been developed for restorative use. It is not yet clear, however, whether the ability of the conventional glass ionomers to bond chemically to dentin has been preserved in the new light-cured glass ionomers whose chemical compositions have been modified. The fracture toughness test was recently introduced as an appropriate method of measuring the fracture resistance of an interface. We have applied this test to the glass ionomer/dentin interface for the first time. Ten mini short-rod fracture-toughness specimens were fabricated for each group. Each specimen contained a chevron-shaped glass ionomer/dentin interface along its midplane. After 24 hours in 37 degrees C water, the specimens were tested by loading at 0.5 mm/min. The interfacial Kic results (MPa X m (1/2)) (SD), analyzed by ANOVA and Fisher's LSD test (P<0.05), were: Chem-fil II, 0.17 (0.04); Vitremer, 0.18 (0.15); Fuji II LC, 0.33 (0.16). There were no significant differences in interfacial Kic between the conventional and light-cured glass ionomers. Interfacial Kic's for a light-cured glass ionomer were, however, significantly higher when an intermediary dentin bonding agent was used. SEM examinations of the fractured surfaces indicated that crack propagation generally occurred along the bond interface, and indicated the formation of a resin-infiltrated layer when the dentin bonding agents were used. It was concluded that the fracture-toughness test could be a useful measure of the integrity of the glass ionomer/dentin interface. The clinical effect of an intermediary layer between the glass ionomer and the tooth structure is, however, unknown and requires further investigation.

Aluminum Silicates↗