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Displaying publications 41 - 45 of 45 in total

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Fulltext DNA methylation and histone modifications are the molecular lock in lentivirally transduced hematopoietic progenitor cells

Ngai SC, Rosli R, Al Abbar A, Abdullah S

Biomed Res Int, 2015;2015:346134.
PMID: 25961011 DOI: 10.1155/2015/346134

Stable introduction of a functional gene in hematopoietic progenitor cells (HPCs) has appeared to be an alternative approach to correct genetically linked blood diseases. However, it is still unclear whether lentiviral vector (LV) is subjected to gene silencing in HPCs. Here, we show that LV carrying green fluorescent protein (GFP) reporter gene driven by cytomegalovirus (CMV) promoter was subjected to transgene silencing after transduction into HPCs. This phenomenon was not due to the deletion of proviral copy number. Study using DNA demethylating agent and histone deacetylase (HDAC) inhibitor showed that the drugs could either prevent or reverse the silencing effect. Using sodium bisulfite sequencing and chromatin immunoprecipitation (ChIP) assay, we demonstrated that DNA methylation occurred soon after LV transduction. At the highest level of gene expression, CMV promoter was acetylated and was in a euchromatin state, while GFP reporter gene was acetylated but was strangely in a heterochromatin state. When the expression declined, CMV promoter underwent transition from acetylated and euchromatic state to a heterochromatic state, while the GFP reporter gene was in deacetylated and heterochromatic state. With these, we verify that DNA methylation and dynamic histone modifications lead to transgene silencing in HPCs transduced with LV.

Matched MeSH terms: Cytomegalovirus/genetics
Lack of methylation on transgene leads to high level and persistent transgene expression in induced pluripotent stem cells

Alhaji SY, Nordin N, Ngai SC, Al Abbar A, Mei L, Abdullah S

Gene, 2020 Oct 20;758:144958.
PMID: 32683073 DOI: 10.1016/j.gene.2020.144958

Short-lived therapeutic gene expression in mammalian cells by DNA methylation is one of the major challenges in gene therapy. In this study, we assessed the implication of DNA methylation on the duration of GFP expression in mouse embryonic stem (ES) and mouse induced pluripotent stem (iPS) cells. The cells were transduced with lentivirus (LV) carrying green fluorescent protein (GFP) driven by either human elongation factor (EF1α) or cytomegalovirus (CMV) promoter. Transduced iPS cells exhibited higher percentage of GFP+ cells with persistent mean fluorescent intensity than transduced ES cells. Analysis on the integrated copy of transgene in the population of the transduced cells demonstrated similar copy number. However, significant increase in GFP intensity following 5-azaC treatment was observed in transduced ES cells only, suggesting the influence of DNA methylation in transgene silencing. Subsequent DNA methylation analysis showed that the promoter and the GFP region of the provirus in iPS cells had negligible methylation profile compared to transduced ES cells. Interestingly, sustained transgene expression was observed upon directed differentiation of transduced iPS cells towards CD34+ CD45+ cells. Hence, this study has shown that favourable transgene activity from lentiviral transduced iPS cells was due to the lack of methylation at the proviral regions.

Matched MeSH terms: Cytomegalovirus/genetics
Plant-derived and semi-synthetic calanolide compounds with in vitro activity against both human immunodeficiency virus type 1 and human cytomegalovirus

Xu ZQ, Kern ER, Westbrook L, Allen LB, Buckheit RW, Tseng CK, et al.

Antivir Chem Chemother, 2000 Jan;11(1):23-9.
PMID: 10693651

Plant-derived and semi-synthetic calanolide compounds with anti-human immunodeficiency virus type 1 (HIV-1) activity were tested for anti-human cytomegalovirus (HCMV) activity in both cytopathic effect inhibition and plaque reduction assays. The results indicated that the anti-HCMV activity of calanolide compounds does not correlate with their activity against HIV-1. The semi-synthetic 12-keto derivatives tended to be more active against HCMV than the corresponding 12-OH congeners, which were more active against HIV-1. It appeared that the 7,8-unsaturated double bond in the chromene ring played a certain role in maintaining activities against both HCMV and HIV-1. Saturation of the double bond increased the EC50 values against both viruses, with concomitant increase in toxicity. The calanolide compounds reported here are the first non-nucleoside analogues capable of inhibiting both HIV-1 and HCMV and, therefore, may be useful chemoprophylactic agents for HCMV in HIV-infected people or vice versa.

Matched MeSH terms: Cytomegalovirus/drug effects*
Fulltext A case of urgent colonoscopic hemostasis of a cecal hemorrhagic ulceration in a patient receiving heparin for COVID-19 coagulopathy

Yoshida N, Hirose R, Watanabe M, Yamazaki M, Hashimoto S, Matsubara S, et al.

JGH Open, 2021 Jan;5(1):160-162.
PMID: 33490630 DOI: 10.1002/jgh3.12435

COVID-19 rarely causes lower gastrointestinal bleeding even though its RNA has been detected in patient's stool. Urgent colonoscopy in a COVID-19 patient with massive bloody stool requires various procedural and equipment considerations. Here, we present a case of colonoscopic hemostasis of a cecal hemorrhagic ulceration in a patient on heparin for COVID-19 coagulopathy. We also share various management methods for the prevention of COVID-19 contamination. A 71-year-old man was diagnosed with COVID-19 pneumonia and subsequently underwent hemodiafiltration. Heparin was initiated for COVID-19 coagulopathy. At day 42, the patient experienced 2000 mL of bloody stool. An operator performed urgent colonoscopy with three assistants in a negative-pressure room with full personal protective equipment. A hemorrhagic ulceration was detected at the cecum, and endoscopic hemostasis was performed. Immunohistochemistry was positive for cytomegalovirus. Postprocedure, the endoscopic systems were thoroughly cleaned, and specific measures for endoscope reprocessing and disinfection were performed to prevent contamination with COVID-19.

Matched MeSH terms: Cytomegalovirus
Optic Nerve Infiltration in Systemic Metastatic Retinal Lymphoma (SMRL): Multimodal Imaging and Challenges in Diagnosis

Mohd Fauzi Yap MFB, Mohd Zain A, Tumain NR, Palaniappan S, Nasaruddin RA, Md Din N

Ocul Immunol Inflamm, 2020 Sep 24.
PMID: 32967510 DOI: 10.1080/09273948.2020.1800050

A 45-year-old man was diagnosed with diffuse large B-cell lymphoma stage IV which was confirmed by celiac lymph node biopsy. He subsequently completed six cycles of R-CHOP chemotherapy. Six months later, he presented with panuveitis OU with positive relative afferent pupillary defect OD. OCT revealed hyper-reflective lesions and irregularity of the retinal pigment epithelium OU. Fundus fluorescein angiogram shows hyper-auto fluorescence and granular changes on the retina. A month later, he developed swollen optic disc OD and hemorrhagic retinitis OU and treated as presumed CMV retinitis. Anti-TB was started after a positive Mantoux test. He finally consented for a vitreous biopsy which showed atypical lymphoid cells highly suggestive for vitreoretinal lymphoma and subsequently received intravitreal methotrexate OU.
CONCLUSION: Optic nerve infiltration in systemic metastatic retinal lymphoma may have initial occult signs but with profound visual loss. Ocular infections like CMV retinitis and tuberculosis may mask and delay the diagnosis in immunocompromised patients.

Matched MeSH terms: Cytomegalovirus Infections