Waleed A Mohammed-Saeid

Dr. Waleed A Mohammed-Saeid


Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

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

Representative Publications

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1 August 2016 in Analytica Chimica Acta
Verified
Journal Article
Open access
JWJamie L. Willems
Jamie L. Willems
MKMona M. Khamis
Mona M. Khamis
WMWaleed A Mohammed-Saeid
Waleed A Mohammed-Saeid
Randy PurvesRandy Purves
Randy Purves
GKGeorge Katselis
George Katselis
AEAnas El-Aneed
Anas El-Aneed
Chlorogenic acids are among the most abundant phenolics found in the human diet. Of these, the mono-caffeoylquinic acids are the predominant phenolics found in fruits, such as apples and pears, and products derived from them. In this research, a comprehensive study of the electrospray ionization (ESI) tandem mass spectrometric (MS/MS) dissociation behavior of the three most common mono-caffeoylquinic acids, namely 5-O-caffeoylquinic acid (5-CQA), 3-O-caffeoylquinic acid (3-CQA) and 4-O-caffeoylquinic acid (4-CQA), were determined using both positive and negative ionization. All proposed structures of the observed product ions were confirmed with second-generation MS(3) experiments. Similarities and differences between the dissociation pathways in the positive and negative ion modes are discussed, confirming the proposed structures and the established MS/MS fingerprints. MS/MS dissociation was primarily driven via the cleavage of the ester bond linking the quinic acid moiety to the caffeic acid moiety within tested molecules. Despite being structural isomers with the same m/z values and dissociation behaviors, the MS/MS data in the negative ion mode was able to differentiate the three isomers based on ion intensity for the major product ions, observed at m/z 191, 179 and 173. This differentiation was consistent among various MS instruments. In addition, ESI coupled with high-field asymmetric waveform ion mobility spectrometry-mass spectrometry (ESI-FAIMS-MS) was employed for the separation of these compounds for the first time. By combining MS/MS data and differential ion mobility, a method for the separation and identification of mono-caffeoylquinic in apple/pear juice samples was developed with a run time of less than 1 min. It is envisaged that this methodology could be used to identify pure juices based on their chlorogenic acid profile (i.e., metabolomics), and could also be used to detect juice-to-juice adulteration (e.g., apple juice addition to pear juice).

1 March 2021 in Carbohydrate Polymers
Verified
Journal Article
Closed access
MVMohammad Reza Vakili
Mohammad Reza Vakili
WMWaleed A Mohammed-Saeid
Waleed A Mohammed-Saeid
AAAbdullah Aljasser
Abdullah Aljasser
JHJulian Hopwood-Raja
Julian Hopwood-Raja
BABehzad Ahvazi
Behzad Ahvazi
ALAfsaneh Lavasanifar
Afsaneh Lavasanifar

14 August 2012 in Journal of Pharmacy & Pharmaceutical Sciences
Verified
Journal Article
Open access
PDF file
WMWaleed A Mohammed-Saeid
Waleed A Mohammed-Saeid
DMDeborah Michel
Deborah Michel
AEAnas El-Aneed
Anas El-Aneed
RVRonald E Verrall
Ronald E Verrall
NLNicholas H Low
Nicholas H Low
Ildiko BadeaIldiko Badea
Ildiko Badea
Purpose. Cationic gemini surfactants have been studied as non-viral vectors for gene therapy. Clinical applications of cationic lipid/DNA lipoplexes are restricted by their instability in aqueous formulations. In this work, we investigated the influence of lyophilization on the essential physiochemical properties and in vitro transfection of gemini surfactant-lipoplexes. Additionally, we evaluated the feasibility of lyophilization as a technique for preparing lipoplexes with long term stability. Methods. A gemini surfactant [12-7NH-12] and plasmid DNA encoding for interferon-γ were used to prepare gemini surfactant/pDNA [P/G] lipoplexes. Helper lipid DOPE [L] was incorporated in all formulation producing a [P/G/L] system. Sucrose and trehalose were utilized as stabilizing agents. To evaluate the ability of lyophilization to improve the stability of gemini surfactant-based lipoplexes, four lyophilized formulations were stored at 25˚C for three months. The formulations were analyzed at different time-points for physiochemical properties and in vitro transfection. Results. The results showed that both sucrose and trehalose provided anticipated stabilizing effect. The transfection efficiency of the lipoplexes increased 2-3 fold compared to fresh formulations upon lyophilization. This effect can be attributed to the improvement of DNA compaction and changes in the lipoplex morphology due to the lyophilization/rehydration cycles. The physiochemical properties of the lyophilized formulations were maintained throughout the stability study. All lyophilized formulations showed a significant loss of gene transfection activity after three months of storage. Nevertheless, no significant losses of transfection efficiency were observed for three formulations after two months storage at 25 ˚C. Conclusion. Lyophilization significantly improved the physical stability of gemini surfactant-based lipoplexes compared to liquid formulations. As well, lyophilization improved the transfection efficiency of the lipoplexes. The loss of transfection activity upon storage is most probably due to the conformational changes in the supramolecular structure of the lipoplexes as a function of time and temperature rather than to DNA degradation. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

16 May 2016 in The AAPS Journal
Verified
Journal Article
Closed access
PDF file
MAMays A. Al-Dulaymi
Mays A. Al-Dulaymi
JCJackson M. Chitanda
Jackson M. Chitanda
WMWaleed A Mohammed-Saeid
Waleed A Mohammed-Saeid
HAHessamaddin Younesi Araghi
Hessamaddin Younesi Araghi
RVRonald E. Verrall
Ronald E. Verrall
Ildiko BadeaIldiko Badea
Ildiko Badea

8 August 2023 in Microorganisms
Verified
Journal Article
Open access
PDF file
AAAreej Alhhazmi
Areej Alhhazmi
RARenad Alhamawi
Renad Alhamawi
RAReema M. Almisned
Reema M. Almisned
HAHanouf A. Almutairi
Hanouf A. Almutairi
AJAhdab A. Jan
Ahdab A. Jan
WMWaleed A Mohammed-Saeid
Waleed A Mohammed-Saeid
Globally, colorectal cancer (CRC) is the second most common cause of mortality worldwide. Considerable evidence indicates that dysbiosis of the gut microbial community and its metabolite secretions play a fundamental role in advanced adenoma (ADA) and CRC development and progression. This study is a systematic review that aims to assess the clinical association between gut microbial markers and/or gut and circulating metabolites with ADA and CRC. Five electronic databases were searched by four independent reviewers. Only controlled trials that compared ADA and/or CRC with healthy control (HC) using either untargeted (16s rRNA gene or whole genome sequencing) or targeted (gene-based real-time PCR) identification methods for gut microbiome profile, or untargeted or targeted metabolite profiling approaches from the gut or serum/plasma, were eligible. Three independent reviewers evaluated the quality of the studies using the Cochrane Handbook for Systematic Reviews of Interventions. Twenty-four studies were eligible. We identified strong evidence of two microbial markers Fusobacterium and Porphyromonas for ADA vs. CRC, and nine microbial markers Lachnospiraceae-Lachnoclostridium, Ruminococcaceae-Ruminococcus, Parvimonas spp., Parvimonas micra, Enterobacteriaceae, Fusobacterium spp., Bacteroides, Peptostreptococcus-Peptostreptococcus stomatis, Clostridia spp.-Clostridium hylemonae, Clostridium symbiosum, and Porphyromonas-Porphyromonas asaccharolytica for CRC vs. HC. The remaining metabolite marker evidence between the various groups, including ADA vs. HC, ADA vs. HC, and CRC vs. HC, was not of sufficient quality to support additional findings. The identified gut microbial markers can be used in a panel for diagnosing ADA and/or CRC. Further research in the metabolite markers area is needed to evaluate the possibility to use in diagnostic or prognostic markers for colorectal cancer.

17 October 2023 in Cancers
Verified
Journal Article
Open access
PDF file
AAAreej Alhhazmi
Areej Alhhazmi
YAYahya Almutawif
Yahya Almutawif
WMWalaa Abdullah Mumena
Walaa Abdullah Mumena
SAShaima M Alhazmi
Shaima M Alhazmi
TATurki S. Abujamel
Turki S. Abujamel
WMWaleed A Mohammed-Saeid
Waleed A Mohammed-Saeid
Colorectal cancer (CRC) is a significant global health concern. Microbial dysbiosis and associated metabolites have been associated with CRC occurrence and progression. This study aims to analyze the gut microbiota composition and the enriched metabolic pathways in patients with late-stage CRC. In this study, a cohort of 25 CRC patients diagnosed at late stage III and IV and 25 healthy participants were enrolled. The fecal bacterial composition was investigated using V3-V4 ribosomal RNA gene sequencing, followed by clustering and linear discriminant analysis (LDA) effect size (LEfSe) analyses. A cluster of ortholog genes’ (COG) functional annotations and the Kyoto Encyclopedia of Genes and Genomes (KEGG) were employed to identify enrichment pathways between the two groups. The findings showed that the fecal microbiota between the two groups varied significantly in alpha and beta diversities. CRC patients’ fecal samples had significantly enriched populations of Streptococcus salivarius, S. parasanguins, S. anginosus, Lactobacillus mucosae, L. gasseri, Peptostreptococcus, Eubacterium, Aerococcus, Family XIII_AD3001 Group, Erysipelatoclostridium, Escherichia-Shigella, Klebsiella, Enterobacter, Alistipes, Ralstonia, and Pseudomonas (Q < 0.05). The enriched pathways identified in the CRC group were amino acid transport, signaling and metabolism, membrane biogenesis, DNA replication and mismatch repair system, and protease activity (Q < 0.05). These results suggested that the imbalance between intestinal bacteria and the elevated level of the predicated functions and pathways may contribute to the development of advanced CRC tumors. Further research is warranted to elucidate the exact role of the gut microbiome in CRC and its potential implications for use in diagnostic, prevention, and treatment strategies.