Infectious Agents and Stroke: A Systematic Review.

INTRODUCTION: A major cause of injury and the second cause of death worldwide is stroke. Among several infectious agents considered as the risk factor of stroke, some pathogens demonstrated stronger robust associations with stroke. Proposing an accurate correlation between infectious microorganisms and stroke provides valuable information for early intervention and control of the infections. METHODS: In this study, we searched the literature using the Web of Science, PMC/Medline via PubMed, and Scopus databases up to July 2018 without time and language restrictions. After quality assessment, 16 articles were included in the study. The whole data extraction process was independently conducted by two reviewers. RESULTS: Based on the results of the studies, viruses, such as Hepatitis C virus (HCV), Hepatitis B virus (HBV), Human Immunodeficiency Virus (HIV), Herpes Simplex Virus Type-1, 2 (HSV-1, 2), Varicella-Zoster Virus (VZV or Chickenpox), and West Nile virus (WNV) seem to be common causes of ischemic stroke. Moreover, the association of other microbial categories, such as Streptococcus mutans (in bacteria), Toxocara spp. and Toxoplasma gondii (in parasites), and Rhizopus sp. (in fungi) with stroke was reported. CONCLUSION: Considering the adverse role of the above-mentioned microorganisms, it is necessary to implement some preventive measures for stroke treatment.

Stroke Associated with SARS-CoV-2 Infection and its Pathogenesis: A Systematic Review.

INTRODUCTION: The change of stroke incidence during the COVID-19 pandemic period and the proposed mechanisms of the relationship between SARS-CoV-2 and stroke is reviewed. METHODS: Web of Science, PMC/Medline, and Scopus databases were searched until July 2020 without time and language limitations. After quality assessment, 22 articles were included in this study. RESULTS: Based on the results, it is impossible to conclude any definite relationship between the rising or decreasing stroke frequency or the shift in the ischemic and hemorrhagic ratio and SARS-CoV-2 infection. However, it appears that SARS-CoV-2 infection has some correlation with stroke. The supposed mechanisms for the SARS-CoV-2-related hemorrhagic stroke include 1) SARS-CoV-2-related vasculopathy with the endothelial damage of small vessels, 2) viral infection-induced platelet dysfunction or thrombocytopenia, and 3) activation of the proinflammatory cascade leading to coagulopathy. The helpful strategies are receiving therapeutic anticoagulation for high D-dimer or a known thrombus due to SARS-CoV-2 infection, as well as using extracorporeal membrane oxygenation (ECMO) in some patients. Furthermore, the possible mechanisms for the SARS-CoV-2-related ischemic stroke include 1) dysregulation of angiotensin-converting enzyme 2 (a key host cellular receptor for SARSCoV-2)-related physiologic functions, 2) endothelial cell damages, 3) thrombo-inflammation, and 4) coagulopathy and coagulation abnormalities related to SARS-CoV-2 infection. CONCLUSION: A better understanding of the SARS-CoV-2 pathogenesis and its relation to neurologic abnormalities such as stroke can help to design new therapeutic approaches.

Diagnosis of Meningitis Caused by Pathogenic Microorganisms Using Magnetic Resonance Imaging: A Systematic Review.

INTRODUCTION: Bacterial meningitis is an acute infectious inflammation of the protective membranes covering the brain. Its early diagnosis is vital because of its high morbidity and mortality. It is mostly diagnosed by a gold standard diagnostic tool i.e. Cerebrospinal Fluid (CSF) analysis. However, it is sometimes difficult and or impossible to do this procedure and an alternative diagnostic tool is needed. Contrast enhanced magnetic resonance imaging can detect the pus or other changes in subarachnoid space. But our optimal aim is to use an imaging method without using contrast to be useable and available in more specific condition. METHODS: This study aimed to survey the role of non-contrast Magnetic Resonance Imaging (MRI) in the diagnosis of the bacterial meningitis. MEDLINE/PubMed Central, Web of Science and Scopus were searched without time period and language limitation until March 2017. We found 6410 papers in our initial search. After assessing the content of the papers based on Cochrane library guidelines and inclusion/exclusion criteria, 6 relevant studies were included in the systematic review. All of included studies were observational studies. RESULTS: MRI studies demonstrated that Fluid Attenuation Inversion Recovery (FLAIR) and Diffusion-Weighted Image (DWI) MR imaging among all MRI modalities can detect some abnormalities compatible with bacterial meningitis. FLAIR and DWI-MR imaging are potentially useful to diagnose bacterial meningitis and can be used in emergent condition in which bacterial meningitis is highly suspicious and the other diagnostic tools are not available or feasible.

Infectious agents and different course of multiple sclerosis: a systematic review.

Multiple sclerosis (MS) causes demyelination of white matter of central nervous system and neuro-degeneration due to inflammation. Different types of MS, as well as disease progression, come with different pathology and pathophysiology. The objective of this study was to evaluate the possible association between different micro-organisms and the relapse or progression of MS. Studies indexed in Medline/PMC, Scopus and Web of Science published without time and language limitation until March 2017 were identified through the search terms "infection" or "infectious" and "multiple sclerosis". A total of 20878 abstracts were identified through the initial search terms. Selection of articles and assessment of their quality was done based on Cochrane library guidelines. Full texts were reviewed for 33 articles out of which 14 articles met the criteria for inclusion. Different micro-organisms are known to play roles in the pathogenesis of MS and its relapse; including Human herpesvirus 6 (HHV-6), Human herpesvirus 7 (HHV-7), Epstein-Barr virus (EBV), Chlamydia pneumoniae and Torque teno virus (TTV). But in this review only HHV-6, C. pneumoniae and TTV have been considered to play a role in disease progression in some studies and not all of them. This review concluded that some micro-organisms such as HHV-6, C. pneumoniae and TTV have been considered as cofactors to make MS a progressive type. It should be considered that these findings do not necessarily rule out the role of other pathogens in MS progression but may represent population differences or different sensitivity of the technique used.

ß-galactosidase Production by Aspergillus niger ATCC 9142 Using Inexpensive Substrates in Solid-State Fermentation: Optimization by Orthogonal Arrays Design.

BACKGROUND: Enzymatic hydrolysis of lactose is one of the most important biotechnological processes in the food industry, which is accomplished by enzyme ß-galactosidase (ß-gal, ß-D-galactoside galactohydrolase, EC 3.2.1.23), trivial called lactase. Orthogonal arrays design is an appropriate option for the optimization of biotechnological processes for the production of microbial enzymes. METHODS: Design of experimental (DOE) methodology using Taguchi orthogonal array (OA) was employed to screen the most significant levels of parameters, including the solid substrates (wheat straw, rice straw, and peanut pod), the carbon/nitrogen (C/N) ratios, the incubation time, and the inducer. The level of ß-gal production was measured by a photometric enzyme activity assay using the artificial substrate ortho-Nitrophenyl-ß-D-galactopyranoside. RESULTS: The results showed that C/N ratio (0.2% [w/v], incubation time (144 hour), and solid substrate (wheat straw) were the best conditions determined by the design of experiments using the Taguchi approach. CONCLUSION: Our finding showed that the use of rice straw and peanut pod, as solid-state substrates, led to 2.041-folds increase in the production of the enzyme, as compared to rice straw. In addition, the presence of an inducer did not have any significant impact on the enzyme production levels.