The objective of this study was to examine the feasibility of detecting toxoplasmic brain lesions in a mouse model of cerebral toxoplasmosis by ultrasmall superparamagnetic particles of iron oxide (USPIO)-enhanced magnetic resonance imaging (MRI). Toxoplasmosis encephalitis was induced in Kunming mice by intracerebral injection of Toxoplasma gondii tachyzoites. T2- and T2*--weighted MRI was performed 1, 3, 4, 5 and 6 days after infection before USPIO injection; immediately after USPIO injection; and 24 h later. A comparison of USPIO enhancement and Gd-DTPA enhancement was made in three toxoplasmic mice 4 days after infection. Hematoxylin and eosin staining and Prussian blue staining were performed to detect inflammatory reactions and presence of iron in and around the toxoplasmic brain lesions. Nonenhanced T2-/T2*-weighted imaging detected few abnormalities in the brain up to 5 days. Most mice developed prominent hydrocephalus at 6 days. Gd-DTPA-enhanced imaging showed prominent enhancement of the cerebral ventricles but revealed only few space-occupying lesions in the parenchyma. USPIO-enhanced T2*-weighted imaging showed improved detection of toxoplasmic brain lesions that were invisible to nonenhanced T2-/T2*-weighted imaging and gadolinium-enhanced imaging. Most of the enhancing lesions showed nodular enhancement immediately after USPIO injection, some of which changed appearance 24 h later, having a ring enhancement at the outer rim. It can be concluded that USPIO enhancement of the toxoplasmic lesions may reflect blood-brain barrier impairment and/or inflammatory reactions associated with these lesions. USPIO-enhanced imaging may be used in combination with gadolinium-enhanced imaging to provide better characterization of toxoplasmic brain lesions and, potentially, improve the differential diagnosis of toxoplasmosis encephalitis.
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http://dx.doi.org/10.1016/j.mri.2007.04.016 | DOI Listing |
PLoS Pathog
January 2025
Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America.
The intracellular protozoan Toxoplasma gondii manipulates host cell signaling to avoid targeting by autophagosomes and lysosomal degradation. Epidermal Growth Factor Receptor (EGFR) is a mediator of this survival strategy. However, EGFR expression is limited in the brain and retina, organs affected in toxoplasmosis.
View Article and Find Full Text PDFVet Parasitol Reg Stud Reports
January 2025
Department of Microbiology & Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA; Department of Public and Ecosystem Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA; Feline Health Center, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA. Electronic address:
Toxoplasmal meningoencephalitis is a sporadic condition that is often misdiagnosed antemortem, frequently resulting in euthanasia especially in resource-limited settings. Here we report a case of a 7-week-old female domestic shorthair cat from an animal shelter who presented in a compromised condition and continued to display clinical signs consistent with a "failure to thrive" kitten. Weight loss and decreased activity were observed, and later on, neurological dysfunction became apparent.
View Article and Find Full Text PDFMicrob Pathog
January 2025
Tropical Projects, Hitchin, United Kingdom. Electronic address:
Background: Toxoplasma infections are highly prevalent worldwide and can cause serious complications in immunocompromised individuals and lead to congenital infections in neonates. Despite ongoing efforts to develop T. gondii vaccines, none have been developed.
View Article and Find Full Text PDFActa Parasitol
January 2025
Department of Medical Parasitology, Faculty of Medicine, Mansoura University, Mansoura, Egypt.
Purpose: The thyroid gland is one of the most vital endocrine organs. It is responsible for the synthesis and secretion of hormones principally triiodothyronine (T3) and thyroxine (T4). These hormones play a significant role in the functions and the metabolism of the body.
View Article and Find Full Text PDFActa Parasitol
January 2025
Department of Microbiology & Immunology, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA.
Background: This study seeks to close this divide by assessing the occurrence of Toxoplasma gondii (T. gondii) in the brain tissues of pet birds displaying neurological symptoms, utilizing Nested Polymerase Chain Reaction (PCR) and Loop-mediated Isothermal Amplification (LAMP) methods. Furthermore, it aims to evaluate and contrast the sensitivity and specificity of different diagnostic procedures.
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