Revisiting Ocular Allergy: Evaluating Symptoms,Benzalkonium Chloride and Efficacy of Topical Ketotifen 0.025%

ABSTRACT

This interesting study raises a scientific issue for revisiting three important elements on diagnosis, use of preservatives and selection of the appropriate topical treatment. Itchy feeling can be encountered in other ophthalmic conditions misdiagnosed as allergy, benzalkonium chloride is responsible for surface toxicity resulting in reduced efficacy and tolerability of topical allergy medications and it should be avoided on the management of ocular allergy. Unpreserved ketotifen 0,025% has been shown to be the least toxic formulation being the optimum option for efficacy and tolerability on the management of ocular allergy.     

Steady-state pharmacokinetics of idebenone in healthy volunteers

An open study was conducted with 12 healthy male Caucasian volunteers to determine the single dose and steady-state pharmacokinetics in plasma after a total daily dose of 90 mg of idebenone administered as 45 mg twice daily for 10 consecutive days. In the dose regimen investigated, multiple daily doses of 90 mg of idebenone were well tolerated by healthy male volunteers and were not associated with any clinically relevant changes in ECG or clinical laboratory parameters. The results of the physical examinations after study termination revealed normal findings in all volunteers. To evaluate the single dose and steady-state pharmacokinetic profile, blood samples were collected at predetermined time points during the study. In those subjects examined, generally good systemic exposure with rapid absorption of idebenone was obtained throughout the entire dosing period. Exposures to idebenone and its metabolites after both single and repeated oral doses of idebenone were comparable in magnitude. Further, the exposures attained were generally consistent with those observed in a previous study after 30 mg three times daily. All pharmacokinetic assessments were associated with a low to moderate degree of inter-subject variability.     

The appropriate use criteria: Improvements for its integration into real world clinical practice

The purpose of this position statement is to suggest ways in which future appropriate use criteria (AUC) for coronary revascularization might be restructured to: (1) incorporate improvement in quality of life and angina relief as primary goals of therapy, (2) integrate the findings of recent trials into quality appraisal, (3) employ the combined information of the coronary angiogram and invasive physiologic measurements together with the results of stress test imaging to assess risk, and (4) recognize the essential role that patient preference plays in making individualized therapeutic decisions. The AUC is a valuable tool within the quality assurance process; it is vital that interventionists ensure that percutaneous coronary intervention case selection is both evidence-based and patient oriented. Appropriate patient selection is an important quality indicator and adherence to evidence-based practice should be one metric in a portfolio of process and outcome indicators that measure quality.     

Hydroxyurea increases hemoglobin F levels and improves the effectiveness of erythropoiesis in beta-thalassemia/hemoglobin E disease

Hydroxyurea (HU) is one of several agents that have been shown to enhance hemoglobin (Hb) F levels in patients with sickle cell disease and may be useful as a therapy for beta-globinopathies. However, limited information exists on the effects of HU in patients with thalassemia. Accordingly, we examined the hematologic effects of orally administered HU in 13 patients with beta-thalassemia/Hb E, including four patients who had been splenectomized. These patients were treated with escalating doses (final range, 10 to 20 mg/kg/d) for 5 months and were observed in the outpatient hematology clinic every 2 to 4 weeks. Complete blood counts including reticulocyte counts, amounts of Hb E and Hb F, G gamma:A gamma and alpha:non-alpha globin biosynthetic ratios were evaluated before and during treatment. Almost all patients responded with an average increase of 33% in Hb F levels, from a mean (+/- SD) of 42% +/- 11% to 56% +/- 8% (P < .0001), and a reciprocal decline in the percentage of Hb E from 59% +/- 9% to 49% +/- 8% (P < .001). Reticulocytosis was decreased from a mean (+/- SD) of 18.0% +/- 15.6% to 11.7% +/- 9.1% (P < .05); there was also a slight (10%) but statistically significant increase in hemoglobin levels and an improved balance in alpha:non-alpha globin chains ratios. The side effects were minimal in most patients, although these patients tended to tolerate a lower dose of HU before significant myelosuppression than has been our previous experience in sickle cell disease. One splenectomized patient died of sepsis during the trial. We conclude that increased Hb F production in beta-thalassemia/Hb E patients, with an improvement in the alpha:non-alpha globin ratios and, probably, the effectiveness of erythropoiesis, can be achieved using HU. Longer trials of HU in this population, including at other doses and in combination with other agents, appear warranted.     

Variation in fetal hemoglobin parameters and predicted hemoglobin S polymerization in sickle cell children in the first two years of life: Parisian Prospective Study on Sickle Cell Disease

Intracellular hemoglobin S (HbS) polymerization is most likely to be the primary determinant of the clinical and biologic manifestations of sickle cell disease (SCD). Fetal hemoglobin (HbF) does not enter the HbS polymer and its intracellular expression in sickle erythrocytes inhibits polymerization. HbF levels, high at birth but decreasing thereafter, protect the newborn from the clinical manifestations of this hemoglobinopathy. We have measured the sequential changes in HbF, F reticulocytes, and F cells in the first 2 years of life in 25 children with SCD and compared the results with those obtained in 30 normal children (AA). We have also calculated HbF per F cell (F/F cell), the preferential survival of F cells versus non-F cells, as measured by the ratio F cells versus F reticulocytes (FC/FR) and polymer tendency at 40% and 70% oxygen saturation. HbF levels decreased from about 80.4% +/- 4.0% at birth to 9.2% +/- 2.9% at 24 months. During this time, we observed a regular decrease of the F reticulocytes and the F cells. The kinetics of the decline of F/F cell was comparable with the decline of HbF, rapid from birth (mean, 27.0 +/- 3.6 pg) to 12 months of age (mean, 8.5 +/- 1.5 pg) and then slower from 12 to 24 months of age (mean, 6.2 +/- 1.0 pg) in the SCD children. In the AA children, the decrease in HbF, due to changes in both numbers of F cells and F/F cell, was more precipitous, reaching steady-state levels by 10 months of age. Calculated values for mean polymer tendency in the F-cell population showed that polymerization should begin to occur at 40% oxygen saturation at about 3 months and increase progressively with age, whereas polymerization at 70% oxygen saturation would not occur until about 24 months. These values correspond to HbF levels of 50.8% +/- 10.8% and 9.2% +/- 2.9%, respectively, and F/F cell levels of 15.6 +/- 4.5 pg and 6.2 +/- 1.0 pg, respectively. In the non--F-cell population, polymerization was expected at birth at both oxygen saturation values. Three individuals had significantly greater predicted polymerization tendency than the remainder of the group because of early decreases in HbF. These individuals in particular, the remainder of the cohort, as well as other recruited newborns, will be studied prospectively to ascertain the relationship among hematologic parameters, which determine polymerization tendency and the various clinical manifestations of SCD.     

Shear stress activation of platelet glycoprotein IIb/IIIa plus von Willebrand factor causes aggregation: filter blockage and the long bleeding time in von Willebrand's disease

The article explores the finding that high shear alone applied to normal, native blood results in platelet aggregation. A filter with tortuous capillary-sized channels permits a study of the effect of shearing forces at different pressures. Native, heparinized, citrated and EDTA blood and platelet-rich plasma (PRP) were forced through the filter. Normal and von Willebrand's blood were studied, as were the effects of antibodies to platelet glycoproteins (GPr) and to von Willebrand's factor (vWf) and of "membrane-active" drugs. Normally, the filter blocked at 40 mmHg but not at 5 mmHg. Transmission electronmicroscopy of the filter at 40 mmHg showed blockage by platelet aggregates. Initially, the mean transit time through the filter was 8 milliseconds. Platelet retention in the filter occurred in two phases. From 0 to 3 seconds, only high-shear, vWf, and GPrIIb/IIIa were required. From 10 to 20 seconds, retention presumably involved these three attributes, but divalent cations were also essential. Only this phase was inhibited by some membrane-active drugs. ADP- and thrombin- induced aggregation requires GPrIIb/IIIaand fibrinogen. Shear-induced blocking of the filter by blood with a normal concentration of fibrinogen requires GPrIIb/IIIa and vWf. This indicates a different type of exposure of GPrIIb/IIIa. The long bleeding time in vW disease highlights the absolute requirement for vWf and emphasizes the difference in exposure of GPrIIb/IIIa induced by shear stress. Evidently, a process similar to that occurring in the filter is required in normal capillary hemostasis.