Effect of congenital ptosis on corneal topography and total aberrometry and comparison of these variables between ptotic and normal fellow eyes.

PURPOSE: To analyze the effect of congenital ptosis on corneal topography and total aberrometry and to compare these variables between ptotic and normal fellow eyes. METHODS: The study included 32 eyes of 16 patients with unilateral congenital blepharoptosis. A Shack-Hartmann wavefront sensor was employed to assess Zernike coefficients and root-mean-square. Computerized corneal topography, Orbscan and aberrometry were measured in the healthy and ptotic eyes. Data were analyzed using SPSS version 16. P<0.05 was considered significant. RESULTS: The mean patient age was 21.31±6.3 years. The mean margin to light reflex distance-1 (MRD-1) was 0.6±1.44mm in the ptotic eyes. Among topography variables, surface regularity index (SRI), cylinder power, irregular astigmatism index (IAI), and flat meridian keratometry were significantly different between ptotic and non-ptotic fellow eyes (P<0.05). Some Orbscan parameters, including simulated keratometry, maximum and minimum corneal power, and astigmatism power were significantly different between ptotic and normal fellow eyes (P<0.05). There was no statistically significant difference in total aberrometry variables between paired eyes. However, in a comparison between ptotic eyes with over 1 diopter astigmatism vs. less than 1 D, high-order Zernike modes without spherical aberration at 6mm (HOW/O Z400 6mm) were significantly different between the 2 groups (P=0.02). CONCLUSION: Unilateral congenital ptosis significantly affects corneal topography and aberrometry, especially in eyes with astigmatism≥1 D. Such differences need to be considered before keratorefractive surgery (KRS).

Validation of Free Formaldehyde Determination Method in DT Vaccine and Tetanus Toxoid Antigen.

Validation is a Good Manufacturing Practice principle that proves any procedure, process, method, equipment, material, activity, or system actually leads to the expected results. This study validates the method for the determination of free formaldehyde in biological products (including the diphtheria-tetanus vaccine and tetanus toxoid antigen). The operating procedure of this method is based on pharmacopoeial monographs. It also does not require full validation, although its suitability under the actual condition of use should be verified. Performance characterizations, such as accuracy, intra-precision (repeatability), intermediate precision (inter-precision), linearity, range, and the limit of quantitation, were investigated and calculated. Accuracy and precision were studied at different concentration levels by spiking known amounts of formaldehyde in real samples. The accuracy and precision results were expressed as the recovery and the relative standard deviation (RSD), respectively. Precision was expressed as intra-precision (repeatability) and inter-precision. Intra-precision or repeatability was performed by one operator in one day by adding three levels of concentration to the products. The inter-precision was conducted by one operator in three individual days within the same laboratory at three concentration levels. Range and linearity were assessed by investigating the correlation coefficient of the regression line between different concentrations of formaldehyde and their response. The acceptance criteria and limits were defined for these validation parameters in these biological products. The RSD for intra-day and inter-day precision studies was less than 5% in a medium concentration of linear range. At this concentration level, accuracy was 90%-110%. The method's linearity ranged between 0.0000039%-0.01% w/v of formaldehyde with a correlation coefficient of 0.9999. The results exhibited sufficient linearity, accuracy, precision, and range. Therefore, this method can be used successfully to determine free formaldehyde for biological products.

Quantification of Melittin in Iranian Honey Bee (Apis mellifera meda) Venom by Liquid Chromatography-electrospray Ionization-ion Trap Tandem Mass Spectrometry (LC-ESI-IT-MS/MS).

The current research aimed to quantify melittin (MEL) in Iranian honey bee (Apis mellifera meda) venom. To this end, a liquid chromatography-electrospray ionization-ion trap tandem mass spectrometry (LC-ESI-IT-MS/MS) approach was employed. Melittin is the main toxic peptide of honey bee venom with various biological and pharmacological activities. It was extracted with pure water from the bee venom samples. The analyses were performed on XBridge BEH300 C4 column using a gradient method with the mobile phase consisting of ultrapure water and acetonitrile (containing 0.1% formic acid). Signals of the melittin were recorded with the selected reaction monitoring (SRM) mode, which is a quantitative approach capable of quantifying analyte peptides with high sensitivity and. The mass spectrum of MEL was obtained in the positive ion mode and the quantification analysis was performed using precursor to product ion transition of m/z 570.2/669.9. This method demonstrated good linearity (R2˃0.997) in the range of 1-100 &micro;g mL-1, with a limit of quantification (LOQ) of 1.0 &micro;g mL-1. The content of MEL in Iranian honey bee venom accounts for 43&ndash;55% of total dry weight. This method can be used to evaluate the quality and authenticity of bee venom samples for different therapeutic applications of MEL.