Rafat Siddiqui

Prof. Rafat Siddiqui


Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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28 October 2011 in BioFactors
Verified
Journal Article
Closed access
PDF file
RSRafat Siddiqui
Rafat Siddiqui
KHKevin A. Harvey
Kevin A. Harvey
ZXZhidong Xu
Zhidong Xu
EBElaine M. Bammerlin
Elaine M. Bammerlin
CWCandace Walker
Candace Walker
JAJeffrey D. Altenburg
Jeffrey D. Altenburg

13 September 2013 in BMC Cancer
Verified
Journal Article
Open access
PDF file
RSRafat Siddiqui
Rafat Siddiqui
KHKevin A Harvey
Kevin A Harvey
CWCandace Walker
Candace Walker
JAJeffrey Altenburg
Jeffrey Altenburg
ZXZhidong Xu
Zhidong Xu
CMCary Mariash
Cary Mariash
The major obstacles to the successful use of individual nutritional compounds as preventive or therapeutic agents are their efficacy and bioavailability. One approach to overcoming this problem is to use combinations of nutrients to induce synergistic effects. The objective of this research was to investigate the synergistic effects of two dietary components: docosahexaenoic acid (DHA), an omega-3 fatty acid present in cold-water fish, and curcumin (CCM), an herbal nutrient present in turmeric, in an in vivo model of DMBA-induced mammary tumorigenesis in mice.

13 August 2012 in Nutrients
Verified
Journal Article
Open access
PDF file
ZXZhidong Xu
Zhidong Xu
KHKevin A. Harvey
Kevin A. Harvey
TPThomas Pavlina
Thomas Pavlina
GDGuy Dutot
Guy Dutot
MHMary Hise
Mary Hise
RSRafat Siddiqui
Rafat Siddiqui
Parenteral nutrition lipid emulsions made from various plant oils contain steroidal compounds, called phytosterols. During parenteral administration of lipid emulsions, phytosterols can reach levels in the blood that are many fold higher than during enteral administration. The elevated phytosterol levels have been associated with the development of liver dysfunction and the rare development of liver failure. There is limited information available in the literature related to phytosterol concentrations in lipid emulsions. The objective of the current study was to validate an assay for steroidal compounds found in lipid emulsions and to compare their concentrations in the most commonly used parenteral nutrition lipid emulsions: Liposyn® II, Liposyn® III, Lipofundin® MCT, Lipofundin® N, Structolipid®, Intralipid®, Ivelip® and ClinOleic®. Our data demonstrates that concentrations of the various steroidal compounds varied greatly between the eight lipid emulsions, with the olive oil-based lipid emulsion containing the lowest levels of phytosterols and cholesterol, and the highest concentration of squalene. The clinical impression of greater incidences of liver dysfunction with soybean versus MCT/LCT and olive/soy lipid emulsions may be reflective of the levels of phytosterols in these emulsions. This information may help guide future studies and clinical care of patients with lipid emulsion-associated liver dysfunction.

18 February 2015 in Lipids in Health and Disease
Verified
Journal Article
Open access
PDF file
KHKevin A Harvey
Kevin A Harvey
ZXZhidong Xu
Zhidong Xu
TPThomas M Pavlina
Thomas M Pavlina
GZGary P Zaloga
Gary P Zaloga
RSRafat Siddiqui
Rafat Siddiqui
Thrombosis and immune dysfunction are two important complications that result from the administration of parenteral nutrition. Endothelial cells within the vasculature are crucial components necessary for maintenance of normal coagulation and immune function. We compared the effects of three commercial lipid emulsions (LEs; Intralipid®, ClinOleic® [or Clinolipid®], and Omegaven®) differing in the levels of omega-6 polyunsaturated fatty acids, omega-3 polyunsaturated fatty acids, omega-9 monounsaturated fatty acids, and saturated fatty acids upon endothelial cell fatty acid composition using Gas chromatography, endothelial cell integrity by assessing measurement of apoptosis and necrosis using flow cytometry, endothelial cell inflammatory activation by assessing the induction of ICAM-1 by lipopolysaccharide [LPS]), and transcription factor activation (phosphorylation of NF-κB) using western blot analysis. Gas chromatographic analysis confirmed cellular uptake of the fatty acids within the LEs; furthermore, these fatty acid changes reflected the composition of the oils and egg phosphatides used in the manufacturing of these emulsions. However, the kinetics of fatty acid uptake and processing differed between LEs. Fish oil LE negatively impacted cell viability by doubling the percentage of apoptotic and necrotic cell populations quantified by flow cytometry using Annexin V/Fluorescein and propidium iodide. The soybean oil LE did not alter cell viability, while the olive oil-predominate emulsion improved cell viability. All LEs were capable of suppressing LPS-induced ICAM-1 expression; however, the fish oil LE was more potent than the other emulsions. Fish oil LE supplementation of cells also suppressed LPS-induced phosphorylation of NF-κB, while the soybean oil and olive predominant LE had no effect upon NF-κB phosphorylation. Lipid emulsions are readily incorporated and stored in the form of triacylglycerols. Soybean oil-based, olive oil-predominant and fish-oil based LEs differentially affected endothelial cell integrity. Importantly, these three LEs were capable of suppressing endothelial cell inflammatory response despite their fatty acid content.

5 August 2014 in European Journal of Lipid Science and Technology
Verified
Journal Article
Open access
PDF file
ZXZhidong Xu
Zhidong Xu
KHKevin A. Harvey
Kevin A. Harvey
TPThomas M. Pavlina
Thomas M. Pavlina
GZGary P. Zaloga
Gary P. Zaloga
RSRafat Siddiqui
Rafat Siddiqui
Parenteral lipid emulsions, which are made of oils from plant and fish sources, contain different types of tocopherols and tocotrienols (vitamin E homologs). The amount and types of vitamin E homologs in various lipid emulsions vary considerably and are not completely known. The objective of this analysis was to develop a quantitative method to determine levels of all vitamin E homologs in various lipid emulsions. An HPLC system was used to measure vitamin E homologs using a Pinnacle DB Silica normal phase column and an isocratic, n‐hexane:1,4 dioxane (98:2) mobile phase. An optimized protocol was used to report vitamin E homolog concentrations in soybean oil‐based (Intralipid®, Ivelip®, Lipofundin® N, Liposyn® III, and Liposyn® II), medium‐ and long‐chain fatty acid‐based (Lipofundin® , MCT and Structolipid®), olive oil‐based (ClinOleic®), and fish oil‐based (Omegaven®) and mixture of these oils‐based (SMOFlipid®, Lipidem®) commercial parenteral lipid emulsions. Total content of all vitamin E homologs varied greatly between different emulsions, ranging from 57.9 to 383.9 µg/mL. Tocopherols (α, β, γ, δ) were the predominant vitamin E homologs for all emulsions, with tocotrienol content < 0.3%. In all of the soybean emulsions, except for Lipofundin® N, the predominant vitamin E homolog was γ‐tocopherol, which ranged from 57–156 µg/mL. ClinOleic® predominantly contained α‐tocopherol (32 µg/mL), whereas α‐tocopherol content in Omegaven® was higher than most of the other lipid emulsions (230 µg/mL).Practical applications: The information on the types and quantity of vitamin E homologs in various lipid emulsions will be extremely useful to physicians and healthcare personnel in selecting appropriate lipid emulsions that are exclusively used in patients with inadequate gastrointestinal function, including hospitalized and critically ill patients. Some emulsions may require vitamin E supplementation in order to meet minimal human requirements.Vitamin E homologs (tocopherols and tocotrienols) contain a chromanol ring and a hydrophobic side chain.

9 June 2012 in Lipids
Verified
Journal Article
Closed access
PDF file
KHKevin A. Harvey
Kevin A. Harvey
CWCandace L. Walker
Candace L. Walker
ZXZhidong Xu
Zhidong Xu
PWPhillip Whitley
Phillip Whitley
RSRafat Siddiqui
Rafat Siddiqui