Epidemiology Profile of Viral Meningitis Infections Among Patients in Qatar (2015-2018).

Background: Little is known about the etiology of meningitis in the MENA region, including Qatar. Viral agents are considered the major cause for meningitis worldwide. Here, we present primary data about the etiology and clinical and demographic characteristics of viral meningitis (VM) in Qatar between 2015 and 2018. Methods: We retrospectively collected data from Hamad Medical Corporation (HMC), which provides about 80% of healthcare services in Qatar. Data were collected for the period between 2015 and 2018. During this time period, 6,705 specimens were collected from patients with suspected meningitis attending HMC and primary healthcare centers. These specimens were tested for a panel of viruses using the "FTD Viral meningitis" multiplex real-time PCR kit that detects Adenovirus (ADV), Human herpesvirus 1&2 (HSV1 and HSV2), Epstein-Barr virus (EBV), Enteroviruses (EV), Cytomegalovirus (CMV), Varicella zoster virus (VZV), and Parechovirus (PV). Results: Only 10.9% (732/6,705) of all suspected meningitis cases were caused by viral agents. 60.9% of the reported cases were males, compared to 39.1% in females. Most of the infections (73.9%) were reported in children younger than 10 years of age. EV were identified as the main causative agent (68.7%), followed by EBV (7.5%) and ADV (6.8%). Other viral agents including VZV, PV, HSV-1, and HSV-2 were also detected with a lower frequency. Confirmed VM were more prevalent among Qatari subjects compared to other nationalities. We observed no specific seasonality of viral agents, but a slight rise was recorded during the spring seasons (March to June). Fever (59.4%, 435/732) and acute central nervous system (CNS) infection (15.6%, 114/732) were initial symptoms of most cases. Conclusion: This is the first report about the molecular epidemiology of VM in Qatar. In line with the international records, our data showed that EV is responsible for 68.7% of Qatar's VM cases. Further studies are needed to genotype and serotype the identified viruses.

Synthesis, Bioapplications, and Toxicity Evaluation of Chitosan-Based Nanoparticles.

The development of advanced nanomaterials and technologies is essential in biomedical engineering to improve the quality of life. Chitosan-based nanomaterials are on the forefront and attract wide interest due to their versatile physicochemical characteristics such as biodegradability, biocompatibility, and non-toxicity, which play a promising role in biological applications. Chitosan and its derivatives are employed in several applications including pharmaceuticals and biomedical engineering. This article presents a comprehensive overview of recent advances in chitosan derivatives and nanoparticle synthesis, as well as emerging applications in medicine, tissue engineering, drug delivery, gene therapy, and cancer therapy. In addition to the applications, we critically review the main concerns and mitigation strategies related to chitosan bactericidal properties, toxicity/safety using tissue cultures and animal models, and also their potential environmental impact. At the end of this review, we also provide some of future directions and conclusions that are important for expanding the field of biomedical applications of the chitosan nanoparticles.

The Current Status of Cytomegalovirus (CMV) Prevalence in the MENA Region: A Systematic Review.

Human cytomegalovirus (CMV) is a highly prevalent herpesvirus worldwide. According to the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO), CMV infects people of all ages, and by the age of five, approximately one-third of children in the United States are infected. Although the infection is generally asymptomatic, it can cause severe disease in immunocompromised patients, transplant and transfusion recipients, as well as newborn neonates. The objective of this study is to systematically review published literature on CMV in the MENA region to estimate its incidence in the region and describe its epidemiological and clinical significance. The literature was searched through four scientific databases: PubMed, Scopus, Science Direct, and Web of Science. A total of 72 studies from 11 countries satisfied the inclusion criteria, covering a period from 1988-2019. The CMV IgG seroprevalence ranged from 8.7%-99.2% (SD = 38.95%). CMV incidence in these countries ranged between 1.22% and 77% in transplant and transfusion recipients, with an increase in incidence with advanced age. However, the incidence rate was unclear for congenital CMV due to the variability of the reporting. This review highlights the need for more robust and well-designed studies to better estimate CMV incidence in the MENA region, standardize diagnostic criteria, and consider prophylactic and pre-emptive treatments to limit the morbidity and mortality of the disease.

Plasmonic MXene-based nanocomposites exhibiting photothermal therapeutic effects with lower acute toxicity than pure MXene.

Purpose: Here, we fabricated two plasmonic 2D Ti3C2Tx-based nanocomposites (Au/MXene and Au/Fe3O4/MXene) with similarly high anti-cancer photothermal therapy (PTT) capabilities, but with less in vivo toxicity than a pure MXene. Methods: Au/MXene was synthesized by in situ reduction of tetrachloroauric acid using NaBH4 on Ti3C2Tx flakes. For targeted PTT, magnetic Au/Fe3O4/MXene was synthesized via a reaction between freshly prepared magnetite Fe3O4 NPs and MXene solution, followed by in situ integration of gold nanoparticles (AuNPs). Results: Morphological characterization by XRD, SEM, and TEM revealed the successful synthesis of Au/MXene and Au/Fe3O4/MXene. Both new composites exhibited a significant in vitro dose-dependent PTT effect against human breast cancer cells MCF7. Interestingly, in vivo acute toxicity assays using zebrafish embryos indicated that Au/MXene and Au/Fe3O4/MXene had less embryonic mortality (LC50 ≫ 1000 µg/mL) than pure MXene (LC50=257.46 µg/mL). Conclusion: Our new Au/MXene and Au/Fe3O4/MXene nanocomposites could be safer and more suitable than the pure MXene for biomedical applications, especially when targeted PTT is warranted.

Using Zebrafish for Investigating the Molecular Mechanisms of Drug-Induced Cardiotoxicity.

Over the last decade, the zebrafish (Danio rerio) has emerged as a model organism for cardiovascular research. Zebrafish have several advantages over mammalian models. For instance, the experimental cost of using zebrafish is comparatively low; the embryos are transparent, develop externally, and have high fecundity making them suitable for large-scale genetic screening. More recently, zebrafish embryos have been used for the screening of a variety of toxic agents, particularly for cardiotoxicity testing. Zebrafish has been shown to exhibit physiological responses that are similar to mammals after exposure to medicinal drugs including xenobiotics, hormones, cancer drugs, and also environmental pollutants, including pesticides and heavy metals. In this review, we provided a summary for recent studies that have used zebrafish to investigate the molecular mechanisms of drug-induced cardiotoxicity. More specifically, we focused on the techniques that were exploited by us and others for cardiovascular toxicity assessment and described several microscopic imaging and analysis protocols that are being used for the estimation of a variety of cardiac hemodynamic parameters.

Zebrafish larvae as a model to demonstrate secondary iron overload.

OBJECTIVES: Thalassemia is the most common genetically inherited blood disorder arising from a defect in hemoglobin production, resulting in ineffective erythropoiesis and severe hemolytic anemia. While transfusion therapy corrects the anemia, it gives rise to secondary iron overload. Current iron chelation therapy performed using deferoxamine, and the efficiency of this drug was demonstrated here using the zebrafish animal model. METHODS: Zebrafish larvae were exposed for 3 days to iron [100 µmol L-1 ferric ammonium citrate; 3-6 days post fertilization (dpf)]. Then, iron treated larvae were exposed to 100 µmol L-1 deferoxamine for 3 days (6-9 dpf). Total tissue iron concentration in the whole larvae, assessed by three different assays; inductively coupled plasma mass spectrometry, colorimetry (spectrophotometry), and microscopy using iron staining followed by imaging and quantification. RESULTS: The three assays showed that iron treatment alone resulted in a significant increase in total iron. Deferoxamine treatment of the iron-loaded zebrafish larvae showed a significant decrease in total iron concentration. CONCLUSION: This study presented a clear evidence of the effectiveness of zebrafish larvae to use as a tool to study iron overload and open the door for studying the efficiency of potential new iron chelating compounds other than commercially available ones.