In response to the expanding landscape of the biotechnology industry and the increasing demand for comprehensive drug development as well as the conduct of preclinical and clinical trials, there is a growing need for employment of diverse animal models, including both small and large animals. The focus of this study was on refining ex vivo culture techniques for bioluminescence imaging following administration of intradermal injections in large animals. To examine the feasibility of our approach, varying concentrations of the rFluc protein were administered to rats and live imaging was employed to validate the corresponding levels of expression. Subsequently, following administration of rFluc to mini-pigs, ex vivo analyses were performed on sample tissues to assess the levels of protein expression across different concentrations. In particular, optimal culturing conditions that facilitated the sustained expression of the protein in samples post-euthanasia were identified. Moreover, by employing small animal imaging devices, we were able to capture clear images of the sample plates, which provided evidence of the successful application of our experimental techniques. The findings from this research represent a significant effort toward refining bioluminescence imaging methods tailored for use with large animal models—an imperative facet of contemporary drug development and biomedical research.

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease by John Cunningham virus (JC virus) infection in oligodendrocytes. The radiographic and clinical features, along with the identification JC in cerebrospinal fluid polymerase chain reaction, are sufficient for the diagnosis of PML in immunodeficiency. However, it is difficult to suspect PML without the patient history of immunodeficiency. A 32-year-old man presented with headache for a month without any medical history. Based on clinical and image features, the differential diagnoses included demyelinating lesion and neoplasms. Microscopically, biopsy specimen showed multifocal demyelinating and degenerative white matter, consistent with PML. Oligodendrocytes cells with increased nuclei and plum-colored inclusions were admixed with perivascular lymphocytic and histiocytic infiltration, and loss of myelin. Atypical astrocytes had large or multiple nuclei. After brain biopsy, human immunodeficiency virus infection was confirmed by serum chemiluminescent immunoassay. It is unlikely that PML would be considered without the information of immunosuppression. Therefore, it is very important to be aware of the histological features of PML.