Parvalbumin expression changes with retinal ganglion cell degeneration.

Background: Glaucoma is one of the main causes of irreversible visual field loss and blindness worldwide. Vision loss in this multifactorial neurodegenerative disease results from progressive degeneration of retinal ganglion cells (RGCs) and their axons. Identifying molecular markers that can be measured objectively and quantitatively may provide essential insights into glaucoma diagnosis and enhance pathophysiology understanding. Methods: The chronic, progressive DBA/2J glaucomatous mouse model of glaucoma and C57BL6/J optic nerve crush (ONC) mouse model were used in this study. Changes in PVALB expression with RGC and optic nerve degeneration were assessed via gene expression microarray analysis, quantitative real-time polymerase chain reaction (qRT-PCR), Western blot and immunohistochemistry. Results: Microarray analysis of the retinal gene expression in the DBA/2J mice at different ages showed that the expression of PVALB was downregulated as the mice aged and developed glaucoma with retinal ganglion cell loss. Analysis of qRT-PCR results demonstrated PVALB at the mRNA level was reduced in the retinas and optic nerves of old DBA/2J mice and in those after ONC compared to baseline young DBA2/J mice. PVALB protein expression measured by Western blot was also significantly reduced signal in the retinas and optic nerves of old DBA/2J mice and those eyes with crushed nerves. Immunohistochemical staining results demonstrated that there were fewer PVALB-positive cells in the ganglion cell layer (GCL) of the retina and staining pattern changed in the optic nerve from old DBA/2J mice as well as in mice eyes following ONC. Conclusion: PVALB is abundantly expressed both by RGCs' soma in the retinas and RGCs' axons in the optic nerves of C57BL/6J. Furthermore, the expression level of PVALB decreases with RGC degeneration in the glaucomatous DBA/2J mice and after ONC injury of C57BL6/6J, indicating that PVALB is a reliable RGC molecular marker that can be used to study retinal and optic nerve degeneration.

A case report of foreign body appendicitis caused by tongue piercing ingestion.

INTRODUCTION: Foreign body ingestion is an uncommon clinical problem in healthy adults. Furthermore, it is even less common for an ingested foreign body to cause any obstructive symptoms within the gastrointestinal tract. PRESENTATION OF CASE: Here, we describe an unusual case of acute appendicitis induced by a tongue piercing that was ingested by a 32-year-old woman with a recent history of endotracheal intubation. Abdominal X-ray revealed metallic foreign bodies in the right lower quadrant. The foreign bodies remained in place on serial X-rays despite bowel preparation and they were not visualized on colonoscopy. Computed tomography (CT) of the abdomen and pelvis confirms the location of the foreign body within the appendix. Laparoscopic appendectomy was performed without complications and the tongue piercing was recovered within the lumen of the resected appendix. DISCUSSION: Foreign body ingestion is a rare cause of appendicitis. Most ingested foreign bodies spontaneously pass through the gastrointestinal tract within a week. However, in rare instances, the foreign body becomes lodged in the appendix, often resulting in appendicitis. CONCLUSION: In patients with appendicitis secondary to foreign body ingestion, we suggest surgical management to reduce the risk of peritonitis, perforation, and abscess formation.

Epigenetic preconditioning with decitabine sensitizes glioblastoma to temozolomide via induction of MLH1.

INTRODUCTION: To improve the standard treatment paradigm for glioblastoma (GBM), efforts have been made to explore the efficacy of epigenetic agents as chemosensitizers. Recent data suggest possible synergy between decitabine (DAC), a DNA hypomethylating agent, and temozolomide (TMZ) in GBM, but the mechanism remains unclear. The objective of this study was to determine the effects of DAC on TMZ sensitization in a consecutively derived set of primary GBM cultures, with a focus on mismatch repair (MMR) proteins. METHODS: Half maximal inhibitory concentrations (IC50) of TMZ were calculated in eleven consecutive patient-derived GBM cell lines before and after preconditioning with DAC. MMR protein expression changes were determined by quantitative immunoblots and qPCR arrays. Single-molecule real-time (SMRT) sequencing of bisulfite (BS)-converted PCR amplicons of the MLH1 promoter was performed to determine methylation status. RESULTS: TMZ IC50 significantly changed in 6 of 11 GBM lines of varying MGMT promoter methylation status in response to DAC preconditioning. Knockdown of MLH1 after preconditioning reversed TMZ sensitization. SMRT-BS sequencing of the MLH1 promoter region revealed higher levels of baseline methylation at proximal CpGs in desensitized lines compared to sensitized lines. CONCLUSIONS: DAC enhances TMZ cytotoxicity in a subset of GBM cell lines, comprising lines both MGMT methylated and unmethylated tumors. This effect may be driven by levels of MLH1 via E2F1 transcription factor binding. Using unbiased long-range next-generation bisulfite-sequencing, we identified a region of the proximal MLH1 promoter with differential methylation patterns that has potential utility as a clinical biomarker for TMZ sensitization.