Publications by authors named "Shakiba Ghaffari"

2 Publications

  • Page 1 of 1

Quantitative microcapillary electrophoresis immunoassay (mCE IA) for end-to-end analysis of pertactin within in-process samples and Quadracel® vaccine.

J Pharm Biomed Anal 2021 Sep 26;204:114284. Epub 2021 Jul 26.

Analytical Sciences Toronto, Sanofi Pasteur Ltd., Toronto, ON, M2R 3T4, Canada. Electronic address:

Protein concentration is an important attribute in the production of subunit or component-based vaccine antigens. Rigorous monitoring of protein concentration is required to identify potential areas for yield improvement. The current GMP method for quantitation is the plate-based ELISA which requires numerous hands-on steps and has low sensitivity in comparison to new microfluidic systems. To address this issue, a sensitive automated microCapillary Electrophoresis ImmunoAssay (mCE IA) method was developed to accurately separate and quantitate pertactin (PRN), an important antigen of the modern acellular Pertussis (aP) vaccine. PRN is reported to be a low-yielding antigen; thus, it is critical to observe its concentration throughout its manufacturing process. First, a primary antibody for PRN was identified to establish suitable immunoprobing conditions for detection of PRN over a wide linear dynamic range that spans 3 orders of magnitude. Next, the pre-adsorbed PRN Drug Substance (DS) was used as a reference standard to quantitate PRN samples against a calibration curve with adequate accuracy and precision. Four representative samples including three in-process steps and final adjuvanted drug product: Quadracel®, were examined to demonstrate the capability of mCE IA to quantitate PRN with high sensitivity and specificity. The matrices of the selected samples contain additional components (e.g. other proteins, growth factors, cell culture media, residual ammonium sulfate, and aluminum adjuvant) often making the quantitation of PRN challenging. The specificity and method linearity were demonstrated by spiking pre-adsorbed PRN DS into the four representative samples. In addition, it was shown that reportable concentrations of PRN for nine downstream process steps as analyzed by our method is comparable to concentrations obtained with ELISA. Most importantly, this study demonstrated that our method's quantitative accuracy is independent of matrix components, as each sample undergoes extensive dilution. This allows for seamless end-to-end analysis of PRN from fermenter harvest, through to complex downstream process samples to adjuvanted drug products. Finally, for the first time the developed and qualified mCE IA method was shown to quantify PRN throughout the entire manufacturing process to provide rapid feedback for process optimizations allowing for accurate yield and step-loss calculations.
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September 2021

Predictors of Leisure Participation in 6 to 14-Year-Old Children with Cerebral Palsy: Structural Equation Modeling.

Iran J Child Neurol 2020 ;14(2):41-57

Proteomics Research Center, Department of Biostatistics, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Objective: The aim of this study was to test a model of child, family and environment and identify factors affecting the intensity of leisure participation by children with cerebral palsy (CP).

Materials & Methods: In this cross-sectional study, 232 children with cerebral palsy (141 boys and 91 girls), aged 6 to 14 years old and their parents were selected from four schools of children with special needs and five rehabilitation centers through the convenience sampling method in Shiraz, Iran. To evaluate the intensity of leisure participation, we used the Persian version of Children's Assessment of Participation and Enjoyment (CAPE) completed by the participants. Demographic form, Craig Hospital Inventory of Environmental Factors (CHIEF), Strengths and Difficulties Questionnaire (SDQ), Family Environmental Scale (FES), SPARCLE cognitive level and parents' version of Gross Motor Function Classification System, Manual Ability Classification System and Communication Function Classification System were sent to the parents with some necessary explanations. Structural equation modeling was used to test the model hypothesis. SPSS version 18 and AMOS version 16 were used for data analysis.

Results: Comparative fit indexes indicated a moderate to good model fit. The presented model explained 44% of the variance in the intensity of participation. Constructs such as Family Activity Orientation with standardized total effect of 0.31 and path coefficients of P< .05 showed the most significant direct effect on participation, followed by higher gross motor function (-.26), higher manual ability (-.19), communication function (-.17), higher cognitive level (-.16), more siblings in the family (.15) and less emotional-behavioral problems (-.15). Family structures and relationships (.17) and unsupportive environment constructs (-.14) demonstrated an indirect but significant effect (P< .05). The relationship of family education level and income with participation was not significant (P>.05).

Conclusion: The intensity of CP children's participation is influenced by child, family and environmental factors. Parents' knowledge of recreational activities and their preference to participate in leisure and recreational activities provide children more opportunities to participate. Higher gross motor function, manual ability, and communication function also play an important role in their participation. Family structure means family cohesion, roles organization, and conflicts between family members and encountering physical, attitudinal and structural barriers at home and community indirectly impact children's participation pattern. To enhance children's participation, we suggest therapists to support children's behaviors, family relationships and involvement in community activities and optimize physical function of children with limitations in self-mobility.
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January 2020