New dual dye for vitreoretinal surgery with increased transparency.

OBJECTIVES: To develop a new dye formulation for vitreoretinal surgery, which shows increased transparency for better intraoperative handling with better parameters important for use. METHODS AND ANALYSIS: A new blue dye, DDG, was synthesised and tested for toxicity and staining. Diglycerol as new density-increasing additive was identified, and its toxicity and lack of influence of the staining with trypan blue (TB) on a collagen membrane as model for the epiretinal membrane was determined. Transparency of the dye solution was evaluated. RESULTS: DDG is as alternative to Brilliant Blue G (BBG), with good staining properties for interna limitans models, and a good safety profile. Diglycerol is a new non-toxic additive replacing PEG3350, with reduced viscosity and no reduction in staining, allowing the reduction of TB to achieve the same staining level of the collagen membrane by 40%, with greater transparency of the dye solution and reduced viscosity. Both factors should facilitate a safe removal during surgery. CONCLUSION: A new dye preparation with improved performance in comparison to marketed combinations of BBG and TB was developed. Its reduced TB concentration and viscosity with maintained density allow better tolerance and handling.

New stains for anterior capsule surgery.

PURPOSE: To investigate whether new dyes and dye combinations can give equivalent or better staining in anterior capsule surgery than existing dyes with a low degree of toxicity on relevant cells. SETTING: University laboratory of Jacobs University Bremen, Germany. DESIGN: Laboratory experimental study. METHODS: Pig eyes were collected post mortem. Cataract was induced by microwave irradiation. Access to the lens capsule was through open-sky surgery. Staining was performed and results were documented by photography. The toxicity of the dyes was evaluated in 3 different cell lines immediately after exposure and with a delay of 24 hours, with exposure in the dark or subsequent strong illumination. RESULTS: A new cyanine dye, BIP (2-[5-[3,3-dimethyl-1-(4-sulfobutyl)-1,3-dihydro-indol-2-ylidene]-penta-1,3-dienyl]-3,3-dimethyl-1-(4-sulfobutyl)-3H-indolium sodium), was found to lead to green staining, with reduced toxicity on corneal endothelial cells. Staining could be further enhanced by combining it with trypan blue. Methylene blue was very toxic, whereas its combination with trypan blue was much less toxic. CONCLUSIONS: With BIP alone or in combination with trypan blue, safe staining of the capsule can be achieved, resulting in a green color.

Toxicity and phototoxicity in human ARPE-19 retinal pigment epithelium cells of dyes commonly used in retinal surgery.

PURPOSE: To compare, for the first time, systematically the toxicity and phototoxicity of dyes and dye combinations used in vitreoretinal surgery. The dyes were trypan blue, brilliant blue G, trypan blue + brilliant blue G, indocyanine green, bromophenol blue, bromophenol blue + brilliant blue G, and acid violet 17, in clinically used concentrations. METHODS: Human ARPE retinal pigment epithelium cells were exposed to the dyes for 30 min. For phototoxicity, the cells were exposed for 15 min to high-intensity light from a light emitting diode source with an intensity similar to surgical conditions. Toxicity was assayed either directly after exposure to either dye alone or dye and light, or with a delay of 24 h. RESULTS: None of the dyes or their combinations was toxic when cells were exposed to them at ambient light. Acid violet led to a reduction viability by 90% already immediately after light exposure. Bromophenol blue and its combination with brilliant blue G showed strong phototoxicity (reduction of viability by 83%) when assayed with delay. Indocyanine green with different agents to adjust osmolarity (balanced salt solution, glucose, and mannitol) was not found to be toxic. CONCLUSION: The strong immediate phototoxicity of acid violet reflects its clinical toxicity. Bromophenol blue might also be disadvantageous for patient outcome because of its delayed phototoxicity. The other dyes (trypan blue, brilliant blue g, and indocyanine green) were not found to be toxic neither with exposure to ambient light nor after exposure to light of intensities used in surgery.

Novel 'heavy' dyes for retinal membrane staining during macular surgery: multicenter clinical assessment.

PURPOSE: To evaluate the feasibility of two novel 'heavy' dye solutions for staining the internal limiting membrane (ILM) and epiretinal membranes (ERMs), without the need for a prior fluid-air exchange, during macular surgery. METHODS: In this prospective nonrandomized multicenter cohort study, the high molecular weight dyes ILM-Blue™ [0.025% brilliant blue G, 4% polyethylene glycol (PEG)] and MembraneBlue-Dual™ (0.15% trypan blue, 0.025% brilliant blue G, 4% PEG) were randomly used in vitrectomy surgeries for macular disease in 127 eyes of 127 patients. Dye enhanced membrane visualization of the ILM and ERMs, 'ease of membrane peeling', visually detectable perioperative retinal damage, postoperative best-corrected visual acuity (BCVA), dye remnants and other unexpected clinical events were documented by 21 surgeons. RESULTS: All surgeries were uneventful, and a clear bluish staining, facilitating the identification, delineation and removal of the ILM and ERMs, was reported in all but five cases. None of the surgeries required a fluid-air exchange to assist the dye application. BCVA at 1 month after surgery improved in 83% of the eyes in the MembraneBlue-Dual™ group and in 88% in the ILM-Blue™ group. No dye remnants were detected by ophthalmoscopy, and no retinal adverse effects related to the surgery or use of the dyes were observed. CONCLUSION: The 'heavy' dye solutions ILM-Blue™ and MembraneBlue-Dual™ can be injected into a fluid-filled vitreous cavity and may facilitate staining and removal of the ILM and/or ERMs in macular surgery without an additional fluid-air exchange.

Dyes for Eyes™: hydrodynamics, biocompatibility and efficacy of 'heavy' (dual) dyes for chromovitrectomy.

As epiretinal membranes (ERMs), the internal limiting membrane (ILM) and the vitreous cortex are essentially transparent tissues, or translucent structures, nontraumatic removal may be challenging in various types of macular surgery. Vital dyes stain these thin tissues, thus allowing for better visualization of these structures during vitrectomy and selective 'membrane peeling' from the underlying retina. To avoid swirling of the dye within the fluid-filled vitreous cavity, and to better target the dye onto the macula, a fluid-air exchange is commonly performed. However, this may jeopardize visualization of the macula during peeling due to clouding of the posterior lens capsule, and may lead to postoperative visual field defects. Recently, a new dye solution for staining the ERM and ILM simultaneously has been developed that circumvents the need for fluid-air exchange, i.e. MembraneBlue-Dual™. This paper will focus on the hydrodynamics and biocompatibility of this 'heavy' dual dye and its efficacy for staining of the ILM and/or ERMs during posterior segment surgery in a multicenter clinical setting.

A bifunctional nanocarrier based on amphiphilic hyperbranched polyglycerol derivatives.

We here report on the synthesis of a bifunctional nanocarrier system based on amphiphilic hyperbranched polyglycerol (hPG), which is modified by introducing hydrophobic aromatic groups to the core and retaining hydrophilic groups in the shell. "Selective chemical differentiation" and chemo-enzymatic reaction strategies were used to synthesize this new core-shell type nanocarrier. The system shows an innovative bifunctional carrier capacity with both polymeric and unimolecular micelle-like transport properties. Hydrophobic guest molecules such as pyrene were encapsulated into the hydrophobic core of modified hPG via hydrophobic interactions as well as π-π stacking, analogous to a unimolecular micelle system. A second guest molecule, which has a high affinity to the shell like nile red, was solubilized in the outer shell of the host molecule, thus connecting the nanocarrier molecules to form aggregates. This model is confirmed by UV-Vis, fluorescence, atomic force microscopy, and dynamic light scattering, as well as release studies triggered by pH-changes and enzymes. Encapsulated guest molecules, respectively in the core and in the shell, present different controlled release profiles. The bifunctional nanocarrier system is a promising candidate for simultaneous delivery of different hydrophobic drugs for a combination therapy, e.g., in tumor treatment.

Cost of transfusion-dependent myelodysplastic syndrome (MDS) from a German payer's perspective.

No curative treatment exists for patients with myelodysplastic syndrome (MDS) besides allogeneic stem cell transplantation. Hence, palliative treatment is provided for a life time accruing high health care cost. As no study in cost of MDS exists in Germany, the objective of this study was to assess and analyze costs of transfusion-dependent low/intermediate-1-risk MDS in Germany from a payers' perspective. From seven centers, 116 low/intermediate-1-risk transfusion-dependent MDS patients with and without isolated 5q-deletion were identified. Claims data and patient records of the previous 5 years were used to collect health care utilization data retrospectively. Publicly available tariff books and remuneration schemes were applied to evaluate mean costs per year in Euro with 2007 as base year. The annual cost of MDS patients was estimated at 14,883. Subgroup analyses showed differences in patient's characteristics and outcomes among patients treated at a hospital-based vs. an office-based setting. Patients treated at the hospital-based registry show higher cost, whereas the reasons for that still need to be detected. Overall, per annum direct costs range from 12,543 (SD 12,967) to 24,957 (SD 36,399) in different subgroups of patients. In both groups, patients with 5q-deletion use more medication than those without deletion. Mean costs for medication in the office-based setting are 5,902 for patients with isolated 5q-deletion vs. 3,932 for patients with no deletion, respectively. MDS leads to a high health care utilization and resulting costs for the health care system which requires a detailed analysis of underlying services.

Structure-biocompatibility relationship of dendritic polyglycerol derivatives.

Nanocarriers possess advanced physicochemical properties that improve bioavailability, enhance cellular dynamics, and control targetability in drug delivery. In particular, dendritic polyglycerol is a promising new biocompatible scaffold for drug delivery. The present explores the structure-biocompatibility relationship of dendritic polyglycerol (dPG) derivatives possessing neutral, cationic, and anionic charges. The effect of solution pH on the surface charge was studied in buffered aqueous solution between pH 4.8 and 7.4. Surface charge properties of dPG derivatives are discussed in terms of surface functionalities and compared with amine and hydroxyl terminated polyamidoamine (PAMAM) dendrimers. Zeta potential measurements and fluorescence quenching studies address the binding interactions of dPGs to bovine serum albumin in order to explore the applicability of dPG derivatives for systemic delivery. Cellular entry of dPG-dye conjugate was evaluated using A549 lung epithelial cells, while in vitro toxicity was studied for various dPGs and compared to PAMAM dendrimers, polyethyleneimine (PEI), dextran, and linear polyethylene glycol (PEG) using human hematopoietic cell line U-937. Cellular uptake studies of dye labelled dPGs inferred that the charged derivatives (dPG-sulfate and dPG-amine) are more rapidly internalized primarily inside the cytosol of A549 cells compared to the neutral dPG. The cell compatibility results show that the dendritic polyglycerols are as safe as linear PEG polymer or dextran, which indicates the suitability of dPG derivatives in delivering therapeutic agents systemically.

Early effects of triamcinolone on vascular endothelial growth factor and endostatin in human choroidal neovascularization.

OBJECTIVE: To evaluate the early effects of triamcinolone acetonide as monotherapy or as an adjuvant to ocular verteporfin photodynamic therapy (PDT) on angiogenesis in human choroidal neovascularization (CNV) secondary to age-related macular degeneration. METHODS: Retrospective review of an interventional series of 55 patients who underwent CNV extraction. Eleven patients were treated with intravitreal triamcinolone acetonide (4 mg) monotherapy (triamcinolone-treated CNV group [n = 5]) or with PDT-triamcinolone combination therapy (PDT-triamcinolone-treated CNV group [n = 6]) 3 to 9 days before surgery. Forty patients who underwent CNV extraction without previous therapy (control CNV group) and 4 patients who underwent CNV extraction 3 days after PDT (PDT CNV group) served as control subjects. The CNV samples were stained for CD34, endostatin, cytokeratin 18, and vascular endothelial growth factor (VEGF). RESULTS: Vascular endothelial growth factor expression was stronger in the PDT CNV samples (P < .001), triamcinolone CNV samples (P = .01), and PDT-triamcinolone CNV samples (P = .007) compared with the control CNV samples. There were no statistically significant differences in VEGF expression among the PDT CNV samples, triamcinolone CNV samples, and PDT-triamcinolone CNV samples. Endostatin expression was weaker in the PDT CNV samples than in the control CNV samples (P = .008). Endostatin expression was stronger in the triamcinolone CNV samples and the PDT-triamcinolone CNV samples compared with the control CNV samples (P = .001 and P < .001, respectively) and the PDT CNV samples (P < .001 for both). CONCLUSION: To some extent, triamcinolone monotherapy seems to exert its angiogenesis inhibitory effects on CNV by enhancing endostatin expression rather than by suppressing VEGF expression.

Short tau inversion recovery and proton density-weighted fat suppressed sequences for the evaluation of osteoarthritis of the knee with a 1.0 T dedicated extremity MRI: development of a time-efficient sequence protocol.

Aim of this study was to develop a time-efficient sequence protocol for a 1.0 T dedicated MR system to be used for whole-organ scoring of osteoarthritis (OA). Thirty-four knees were examined using a protocol that included fat suppressed fast spin echo proton density weighted sequences (PDFS) in three planes plus a coronal STIR sequence. Two radiologists scored each knee by consensus for five OA features. In separate sessions, all knees were scored using three different combinations of sequences: (1) all four sequences (reference protocol, 16 min 31 s scanning time), (2) three PDFS sequences without STIR ("No STIR", 12 min 25 s scanning time) and (3) sagittal and axial PDFS sequences plus a coronal STIR sequence ("No PDFS", 11 min 49 s scanning time). Agreement of the readings using both subsets of sequences compared to the reference protocol was evaluated using weighted kappa statistics. kappa-coefficients showed good or excellent agreement for both sequence subsets in comparison to the reference protocol for all assessed features. kappa-coefficients for No PDFS/No STIR: bone marrow abnormalities (0.74/0.67), subarticular cysts (0.84/0.63), marginal osteophytes (0.77/0.71), menisci (0.75/0.79), tibial cartilage (0.71/0.78). Optimization of sequence protocols consisting of three sequences results in time savings and cost efficiency in imaging of knee OA without loss of information over a more time consuming protocol.

Trypan blue staining in vitreoretinal surgery.

PURPOSE: To evaluate the efficacy of trypan blue for staining the internal limiting membrane (ILM) and epiretinal membranes (ERM) in vitreoretinal surgery. DESIGN: Prospective noncomparative case series. PARTICIPANTS: Fifty eyes of 50 patients with macular pucker (n = 22), macular hole (n = 18), or a combination (n = 2), proliferative vitreoretinopathy (n = 5), or diabetic retinopathy (n = 3). METHODS: Trypan blue 0.2% was used to stain the ILM or ERM during vitreoretinal surgery. MAIN OUTCOME MEASURES: The intraoperative visibility of the membranes was scored as poor, moderate, good, or excellent. RESULTS: The application of trypan blue onto the ILM or the ERM resulted in a useful bluish staining, facilitating the identification, delineation, and removal of the membranes in all surgeries. No residual staining or adverse effects related to the dye were observed. CONCLUSIONS: Trypan blue stains both ILM and ERM and might be an useful tool in vitreoretinal surgery.

The value of water-excitation 3D FLASH and fat-saturated PDw TSE MR imaging for detecting and grading articular cartilage lesions of the knee.

OBJECTIVE: To evaluate the diagnostic accuracy of water-excitation (WE) 3D FLASH and fat-saturated (FS) proton density-weighted (PDw) TSE MR imaging for detecting, grading, and sizing articular cartilage lesions of the knee. DESIGN AND PATIENTS: A total of 26 patients underwent MR imaging prior to arthroscopy with the following sequences: (1) WE 3D FLASH: 28/11 ms, scan time: 4 min 58 s, flip angle: 40 degrees; (2) FS PDw TSE: 3433/15 ms, scan time: 6 min 15 s, flip angle: 180 degrees. Grade and size of the detected lesions were quantified and compared with the results of arthroscopy for each compartment. RESULTS: The sensitivity, specificity, positive and negative predictive values, and accuracy for detecting cartilage lesions were 46%, 92%, 81%, 71% and 74% for WE 3D FLASH and 91%, 98%, 96%, 94% and 95% for FS PDw TSE MR imaging. WE 3D FLASH correlated significantly with arthroscopy for grading on the patella ( P<0.0001) and the femoral trochlea ( P=0.02) and for sizing on the femoral trochlea ( P=0.03). FS PDw correlated significantly ( P<0.0001) with arthroscopy for grading and sizing on all compartments. CONCLUSION: FS PDw TSE is an accurate method for detecting, grading and sizing articular cartilage lesions of the knee and yielded superior results relative to WE 3D FLASH MR imaging.