New guidelines in the treatment of persistent central serous chorioretinopathy: PDT with half-dose verteporfin.

BACKGROUND: In persistent central serous chorioretinopathy (CSC) resolution of detachment can be achieved by photodynamic therapy. Our objective was to evaluate the efficacy of half-dose verteporfin compared to full-dose verteporfin. PATIENTS AND METHODS: In 2009 the standard PDT regimen for CSC in our clinic was changed from full-dose to half-dose verteporfin. After a retrospective analysis 11 cases of half-dose PDT with documented course in 11 patients are presented. A comparison was performed with a control group of 11 consecutive patients with documented course who had received full-dose PDT before 2009. RESULTS: Prior to PDT there were no statistically significant differences between the groups concerning age, central foveal thickness, thickness of detachment, BCVA (EDTRS) and size of spot. 6 weeks after PDT a significant reduction of foveal thickness and detachment was detected in both groups, as well as a significant increase in BCVA. No statistically significant differences in outcome could be found between the two groups (Mann-Whitney U-test, p < 0.05). CONCLUSIONS: PDT with half-dose verteporfin seems to be an effective and safe treatment for persistent CSC. Our data showed comparable results after half-dose and after full-dose PDT.

Investigation of protoporphyrin IX standard materials used in acid-extraction methods, and a proposed correction for the millimolar absorptivity of protoporphyrin IX.

Erythrocyte protoporphyrin (EP) has been used for more than 30 years as an indicator of lead intoxication, iron deficiency, and porphyrias. Recently, numerous analytical problems associated with various EP methods have been reported, including a lack of consensus among investigators regarding the best calibration material or analytical procedure. We investigated commercially available protoporphyrin IX (PPIX) standard materials and measured the millimolar absorptivity (m epsilon) of these materials, focusing on variables affecting the determination of their absorptivities. Among the five forms of PPIX available, PPIX dimethyl ester, when hydrolyzed to PPIX free acid, gave the most consistent and reproducible results. This work confirmed our earlier observations, made on more than 600 separate occasions during 12 years, that the m epsilon of PPIX free acid in 1.5 mol/L HCl at the Soret maximum is 297 +/- 1.3 L.mmol-1.cm-1, 19% higher than the arbitrary value of 241 L.mmol-1.cm-1 generally accepted by most investigators but based on unpublished data. We propose that the m epsilon of 297 L.mmol-1.cm-1 for PPIX be adopted and that PPIX dimethyl ester be used for the calibration of acid-extraction methods. A detailed protocol for the preparation and verification of PPIX from the dimethyl ester is available upon request.

Loss of porphyrins from solution during analysis: effect of sample pH and matrix on porphyrin quantification in urine by "high-performance" liquid chromatography.

We report the effect of sample matrix and pH on quantification of porphyrins by HPLC with fluorimetric detection. For aqueous solutions of pH less than 2.5, HPLC peak heights of the porphyrins increased with decreasing pH, reaching a plateau at pH less than 1.0. This loss of porphyrins from solutions with pH greater than 1.0 appeared to be due to a combination of microprecipitation and aggregation effects. No such "pH effect" was observed for urine samples supplemented with mixed-porphyrin standards. Addition of trace amounts of albumin to aqueous solutions also decreased these pH-related losses. These findings suggest a porphyrin-protein interaction that prevents microprecipitation and aggregation processes. We conclude that standard solutions of porphyrins for HPLC analysis should be prepared in a urine matrix. If aqueous solutions are used, then the pH must be adjusted to less than 1.0. Urine samples from normal individuals require only adjustment of pH to less than 2 before analysis; however, porphyric urines requiring dilution should be prepared with porphyrin-free urine diluent.

Tissue porphyrin pattern determination by high-speed high-performance liquid chromatography.

A rapid and sensitive method for the determination of porphyrin carboxylic acids in liver, kidney, and spleen by high-speed high-performance liquid chromatography is described. Porphyrins were extracted with recoveries greater than or equal to 98%, concentrated on disposable octadecylsilyl cartridges, and analyzed with a liquid chromatograph equipped with a 3 microns X 3 cm octadecylsilyl column and a fluorescence detector. Separation of di-, tetra-, penta-, hexa-, hepta-, and octacarboxylic acids was achieved within 5 min. The detection limits for uro, copro, and protoporphyrin were 20, 10, and 20 fmol, respectively.

An internal standard for porphyrin analysis.

The routine clinical analysis of the porphyrin precursors of heme requires an internal standard to determine the efficiency of the analytical procedure used. 2-Vinyl-4-hydroxymethyldeuteroporphyrin IX has been prepared as an internal standard. Its application to porphyrin analysis has been demonstrated using high-performance liquid chromatographic resolution of the uro- to protoporphyrins in normal and porphyric urine.

Systematic error between erythrocyte protoporphyrin in proficiency test samples and patients' samples as measured with two hematofluorometers.

Hematofluorometers manufactured by two different companies (Aviv Biomedical and Environmental Science Associates) performed satisfactorily for protoporphyrin determinations with proficiency test samples but showed about a 30% low bias with actual clinical blood specimens.