Triamcinolone intravitreal injection and intraocular pressure in macular edema associated with retinal vein occlusion.

PURPOSE: To study the risk factors of increased intraocular pressure (IOP) response to triamcinolone acetonide intravitreal (IVTA) injection in eyes with macular edema associated with retinal vein occlusion. METHODS: Eighty-nine eyes with macular edema associated with retinal vein occlusion first received periocular injection of 40 mg triamcinolone acetonide (TA) and were followed for one month. According to the diversity of IOP after periocular TA (PTA) injection, they were divided into the elevation IOP group (group A, 26 eyes) and the normal IOP group (group B, 63 eyes). They then received 4 mg TA intravitreal injection. IOP measurements were recorded after PTA and IVTA injections, and were followed for six months. RESULTS: Both PTA and IVTA injections caused a rise in IOP, but it was higher in the IVTA injection (40.45%) than in the PTA injection (29.21%). The mean rise in IOP was more significant in eyes with IVTA injection (28.08 ± 8.24 mmHg) than in eyes with PTA injection (20.87 ± 4.07 mmHg). Patients with an elevation IOP above 6 mmHg after PTA injection had a 73.08% chance of developing a pressure of 24 mmHg or higher, whereas only 12.70% of those with an elevation IOP below 6 mmHg after PTA injection experienced pressure elevation. CONCLUSION: IOP response to PTA injection is a good way to judge IOP response to IVTA. If the patient is highly sensitive to corticosteroid, treatments other than IVTA injection are used to avoid the increased risks associated with intravitreal corticosteroid injection.

[A spectral unmixing method of estimating main minerals abundance of lunar soils].

Estimating minerals abundance from reflectance spectra is one of the fundamental goals of remote sensing lunar exploration, and the main difficulties are the complicated mixing law of minerals spectrum and spectral features being sensitive to several kinds of factors such as topography, particle size and roughness etc. A method based on spectral unmixing was put forward and tested in the present paper. Before spectra are unmixed the spectral continuum is removed for clarifying and strengthening spectral features. The absorption features and reflectance features (the upward curving parts of spectra between absorption features) are integrated for unmixing to improve the unmixing performance. The Hapke model was used to correct unmixing error due to nonlinear mixing of minerals spectra. Forty three mixed spectra of olivine, clinopyroxene, hypersthene and plagioclase were used to validate the above method. The four minerals abundance was estimated under the conditions of being unaware of endmember spectra used to mix, granularity and chemical composition of minerals. Residual error, abundance error and correlation coefficient between retrieved and true abundance were 5.0 Vol%, 14.4 Vol% and 0.92 respectively. The method and result of this paper could be referred in the lunar minerals mapping of imaging spectrometer data such as M3.

[Change of plasma endothelin-1 concentrations in photodynamic induced rat anterior ischemic optic neuropathy model and drug modulation].

OBJECTIVE: To investigate changes of plasma endothelin-1 (ET-1) concentration in photodynamic induced rat anterior ischemic optic neuropathy model (rAION) and evaluate the effects of compound anisodine hydrobromide (CA). METHODS: Eighty-five Sprague-Dawley (SD) male rats were randomly divided into a blank control group of 10 rats and a model group of 75 rats. rAION model was established in the model group by photodynamic induction. The model group was divided into a rAION simple group of 25 rats, a CA intervention group of 25 rats, and a normal saline (NS) control group of 25 rats. Beginning from the day that the rAION model was established, temporal subcutaneous injections (once daily for 3 days) of CA and NS were performed in the CA and the NS groups, respectively. The plasma ET-1 concentrations were detected by radioimmunoassay and analyzed at 1, 3, 5, 7 and 14 days. RESULTS: The means plasma ET-1 concentration of rAION simple group is (114.9±17.6) ng/L, higher than that of the control group (69.4±9.1) ng/L (t=14.92, P<0.01). In the rAION model group, the plasma ET-1 concentrations 1 to 5 days after the model was established were higher than that of 7 to 14 days. During observational periods, on the 1st, 5th, 7th and 14th day, there was no significant difference between the CA and NS groups (t=0.58, 2.07, 0.81 and 0.93, P>0.05), but on the 3rd day the level of plasma ET-1 concentration in the CA group was significantly lower than that of the NS group (t=4.72, P<0.05). CONCLUSIONS: Increase of plasma ET-1 concentrations may play an important role in the pathogenesis of photodynamic induced rAION model. CA can decrease the plasma ET-1 concentrations in rAION rats.