Human Platelets Take up Anti-VEGF Agents.

PURPOSE: Growing evidence suggests different systemic exposure of anti-vascular endothelial growth factor (anti-VEGF) agents with repeated intravitreal application. Since the penetration of anti-VEGF agents through vascular barrier was reported, the interaction of anti-VEGF with nonresident platelets has become a topic of interest. The purpose of this study was to evaluate, with the help of visualization techniques, whether platelets take up the anti-VEGF agents ranibizumab, aflibercept, and bevacizumab. METHODS: The uptake of anti-VEGF agents with or without VEGF treatment was investigated using immunofluorescence and immunogold staining in human platelets. The role of actin filaments and clathrin-coated vesicles in the transport of ranibizumab, aflibercept, and bevacizumab was evaluated by two pharmacologic inhibitors: staurosporine (protein kinase C inhibitor) and cytochalasin D. RESULTS: All three anti-VEGF agents were taken up by platelets and colocalized with VEGF. Ranibizumab and aflibercept were mainly detected in alpha-granules; however, bevacizumab was equally localized in alpha-granules and in platelet vesicles. Both staurosporine and cytochalasin D completely inhibited the uptake of aflibercept into platelets. Both pharmacological inhibitors also decreased the transport of ranibizumab and bevacizumab into platelets. Bevacizumab was significantly more frequently colocalized within clathrin-coated vesicles than ranibizumab and aflibercept. CONCLUSION: All three anti-VEGF agents are taken up by platelets and internalized in alpha-granules, which may result in a higher local exposure of anti-VEGF after the activation of platelets, potentially contributing to arterial thromboembolic events. Clathrin-coated vesicles seem to be more prominent in the transport of bevacizumab than ranibizumab and aflibercept. Nevertheless, whether the different localization and transport of bevacizumab are truly related to specific differences of receptor-mediated endocytosis has to be revealed by further research.

Efficacy of Topical Ivermectin for the Treatment of Cutaneous and Ocular Rosacea.

Purpose: To investigate the efficacy of once-daily topical treatment of ocular and cutaneous rosacea with ivermectin 1% cream (Soolantra®, Galderma).Methods: Ten patients with rosacea were evaluated in a retrospective monocentric pilot study. Subjective symptoms (measured with the Ocular Surface Disease Index), skin findings, and ocular changes (blepharitis with telangiectasia and meibomian gland dysfunction, conjunctival redness, tear breakup time (TBUT), and fluorescein staining of the cornea) were evaluated. The follow-up was 8 months (range: 5-12 months).Results: The OSDI score decreased in the 8th week of treatment (38.5 ± 21.7, P = .004). After 16 weeks, blepharitis (P = .004), and conjunctival redness (P = .008) had strongly improved, and grade 1 was seen in all patients until the end of follow-up. Fluorescein staining of the cornea (P = .001) and TBUT (P = .016) showed significant improvement until the last follow-up visit. No side effects were observed. Conclusion: Topical ivermectin cream 1% given daily is an effective and safe therapy against rosacea.

Influence of aflibercept on platelet activation profile.

Aflibercept appears to accumulate in systemic circulation following intravitreal injections in therapy of neovascular age-related macular degeneration. This gives raise to the question of whether aflibercept affects platelets and their function such as activation and aggregation, which are substantial in the pathogenesis of an arterial thromboembolic event (ATE). In order to determine the effect of aflibercept in platelet activation, platelets from healthy volunteers were treated with aflibercept and its solvents at equal concentrations (0.04 µg/mL - 4 µg/mL - 40 µg/mL - 400 µg/mL - 4 mg/mL) for 10 and 30 min before addition of agonists. IgG1 antibody was used as a control. The surface expression of GPIIb/IIIa, P-selectin, and platelet-bound stromal-cell-derived factor-1, which are potential blood biomarkers for ATEs, was determined on resting and activated platelets by the multispectral imaging flow cytometry, combining the features of flow cytometry with fluorescence microscopy. Platelet aggregation was assessed with light transmission aggregometry. To determine whether aflibercept directly interacts with platelets, aflibercept was labeled with the fluorescence FITC. Co-treatment of platelets with thrombin or PAR-4-AP and aflibercept resulted in increased activation of the fibrinogen receptor GPIIb/IIIa in comparison to controls (P < 0.05). Interestingly, the expression of platelet-derived P-selectin and SDF-1 was not affected by aflibercept, except thrombin-activated CD62P with 0.04 µg/mL aflibercept (aflibercept vs. its solvent: MSI = 1.54, IC = 1.201-1.879 vs. MSI = 1.37, IC = 1.136-1.604 [P = 0.031]) and SDF-1 with 4 mg/mL aflibercept (aflibercept vs. its solvent: MSI = 1.971, IC = 1.206-2.737 vs. MSI = 1.200, IC = 0.738-1.662 [P = 0.041]). Although the levels of platelet-bound aflibercept-FITC were significantly increased in all activated platelets, no effect was observed in platelet aggregation. Albeit no impact of aflibercept was found on platelet aggregation under the studied experimental conditions, the increased activation of the fibrinogen receptor GPIIb/IIIa and the presence of a direct interaction between aflibercept and platelets may partially explain the risk of ATE in patients under aflibercept treatment due to FcγRIIa mediated αIIbß3 outside-in integrin signaling and transport of aflibercept into platelets. Therefore, the Fc domain seems to be involved in interactions between aflibercept and platelets. Further research is needed to explain the role of Fc containing aflibercept in the pathogenesis of drug-associated vascular events involving platelets, coagulation cascade, extracellular matrix proteins and other cells.

[Atopic keratoconjunctivitis]. / Atopische Keratokonjunktivitis.

It is useful to define atopic keratoconjunctivitis (AKC) as a non-infectious inflammatory condition of the ocular surface, which is associated with atopy. The pathogenesis of the disorder is not completely understood. The diagnosis is based on the patient's history and the clinical manifestations. Successful management of AKC, which can become a serious condition, requires a multidisciplinary approach that involves prevention, dermatological care and an adequate ophthalmological treatment algorithm.

Long-term oral therapy with valganciclovir in patients with Posner-Schlossman syndrome.

BACKGROUND: To assess the short-term and long-term efficacy of oral therapy with valganciclovir in patients with Posner-Schlossman Syndrome (PSS). METHODS: This is a retrospective observational study on 11 patients with PSS treated with valganciclovir. The PSS was diagnosed clinically on the basis of recurrent episodes of anterior uveitis associated with attacks of elevated intraocular pressure (IOP). All patients who did not respond to aciclovir, or whose cytomegalovirus (CMV) DNA polymerase chain reaction (PCR) analysis of the aqueous humour was positive, were treated with valganciclovir (Valcyte®). Initially, the drug was given 900 mg twice daily for 3 weeks, followed by 450 mg twice daily for a mean period of 20 months (range 10-46 months). RESULTS: Eleven patients with mean age of 44 years were included in this study. Four of 11 patients were working in a sanitary profession. Before initiation of valgancicloivir therapy, the highest IOP was 68 mmHg (mean 45 mmHg ±9 mmHg). In the first week of treatment, the IOP decreased significantly (mean 16 mmHg ±10 mmHg) and maintained stability during the entire treatment period. In seven of 11 (63.6 %) patients, valganciclovir led to resolution of inflammatory activity and stable IOP. In six patients, the therapy could be discontinued after a mean of 14 months. However, two patients had a recurrence after discontinuation of valganciclovir treatment. No side effects of therapy were observed. CONCLUSIONS: Long-term oral therapy with valganciclovir seems to lower the recurrence rate in patients with clinically diagnosed PSS.

[Ocular rosacea]. / Ophthalmorosazea.

Half of patients with rosacea develop ocular involvement. The complaints are often nonspecific. The most common ocular manifestation is blepharoconjunctivitis with dry eye, while on rare occasion rosacea keratitis can lead to corneal ulcer, which then requires urgent ophthalmologic consultation. Topical therapy with preservative-free artificial lubricants and lid hygiene is recommended for the primary treatment of ocular rosacea. Secondarily, systemic medications are indicated depending on severity of the ocular and skin findings.

[Discrete bilateral corneal deposits in a young woman]. / Diskrete bilaterale korneale Ablagerungen bei einer jungen Frau.

A 17-year-old asymptomatic girl presented with discrete bilateral deposits in the superficial corneal stroma. The diagnosis of very early and in this form as yet undescribed manifestation of Schnyder's corneal dystrophy, was only possible based on the family history.

Characterization of erythrocyte compounds in asphyxiated newborns.

Perinatal hypoxic-ischemic damage remains a major cause of acute mortality in infants. In our study we have shown that ATP-powered calcium pump was degraded in asphyxiated erythrocyte membranes. Moreover, the activity of Ca2+-ATPase, the enzyme that is solely responsible for maintenance of calcium homeostasis in erythrocytes, was reduced by 50% compared to healthy newborns. We have also detected the enhanced lipid peroxidation in asphyxiated erythrocyte ghosts. To elucidate the potential mechanisms of the calcium pump damage, we have examined the effect of peroxynitrite on Ca2+-ATPase purified from adult human erythrocyte membranes. We have concluded that calcium pump is a direct target for peroxynitrite action in vitro. Our results indicate that erythrocyte membrane compounds could be a primary target for asphyxia-induced damage, and the impairment of the plasma membrane Ca2+-ATPase function could be, in part, mediated by reactive oxygen species.

Can magnesium sulfate reduce the risk of cerebral injury after perinatal asphyxia?

Hypoxia-ischemia produces brain damage by processes that continue for many hours after reoxygenation/reperfusion. This provides a window of opportunity for therapy aimed at preventing further loss of brain cells. Sulfate magnesium can prevent posthypoxic brain injury by blocking glutamate receptors within the calcium (Ca++) ion channel. We used sulfate magnesium in nine newborn infant after perinatal hypoxia. We investigated the brain damage, by ultrasound examination, on third day, in first, second and third week, and third, sixth month of life. We have estimated the neurological development in the first week of life and third and twelfth month of life. We did not find deviations in ultrasound examination. We did not observe convulsions. We did not observe any side effect of this therapy. The examination at 1 of year of life in all of children was correct.

Pendulum equations for a swept-gain three-level amplifier.

We present new pendulum-type equations for the propagation of two nonoverlapping pulses in a model swept-gain three-level amplifier. The predictions of these equations are compared numerically with corresponding predictions of the two-level Burnham-Chiao equations and with the full coupled three-level Maxwell-Bloch equations.

Resonance fluorescence and a new type of double resonance.

The quantum-mechanical description of a two-level molecule interacting simultaneously with a strong laser field and a rf field of an arbitrary intensity is presented. The stationary intensity of the optical fluorescence is calculated. When the energy of 2n rf quanta is close to that of the Stark splitting, a reduction is predicted in the fluorescence intensity.

Obtaining, evaluation and clinical application of antileukemic antilymphocyte globulin (ALLG) in the treatment of chronic lymphatic leukemia.

Antileukemic antilymphocyte globulin (ALLG) was obtained by immunizing horses with peripheral blood lymphocytes from patients suffering from chronic lymphatic leukemia. After absorbing the serum with erythrocytes, globulins were precipitated from the serum with ammonium sulfate. ALLG preparations were sterile, nontoxic and nonpyrogenic and contained no antibodies against basement membranes or antierythrocytic or antiplatelet antibodies. Nine patients with chronic lymphatic leukemia were treated with the globulin. Methods for selecting patients for treatment with ALLG and for controlled therapy were elaborated. Clinical and hematologic observation in the patients were reported. The high therapeutic efficacy of ALLG with high cytotoxic titer was emphasized. Beneficial hematologic and therapeutic effects were obtained in six patients. Attention was drawn to the efficiency of the combined therapy with ALLG, cytostatics and adrenal steroids.