Variable Record Table: A Run-time Solution for Mitigating Buffer Overflow Attack

We present a novel approach to mitigate buffer overflow attack using Variable Record Table (VRT). Dedicated memory space is used to automatically record base and bound information of variables extracted during runtime. We instrument frame pointer and function(s) related registers to decode variable memory space in stack and heap. We have modified Simplescalar/PISA simulator to extract variables space of six (6) benchmark suites from MiBench. We have tested 290 small C programs (MIT corpus suite) having 22 different buffer overflow vulnerabilities in stack and heap. Experimental results show that our approach can detect buffer overflow attack with zero instruction overhead with the memory space requirement up to 13Kb to maintain VRT for a program with 324 variables.Comment: Accepted for publication in MWSCAS201

Incisional Hernia Involving the Neobladder: Technical Considerations to Avoid Complications

The management of incisional hernia following radical cystectomy (RC) and neobladder diversion poses a special challenge. Mesh erosion into the neobladder is a potential complication of hernia repair in this setting. We describe our experience and steps to avoid this complication. Three patients developed incisional hernias following RC involving the neobladder. The incisional hernias were repaired by the same surgeon. A systematic dissection and repair of the hernias with an onlay dual-layer mesh (made of polyglactin and polypropylene) was carried out. The critical steps were placing the polyglactin side of the mesh deeper and positioning of an omental flap anterior to the neobladder. The omental flap adds a protective layer that prevents adhesions between the neobladder and abdominal wall, and prevents erosion of the mesh into the fragile neobladder wall. All of these patients had received two cycles of neoadjuvant chemotherapy prior to RC. The time duration from RC to the repair of hernia was 7, 42, and 54 months. No intraoperative injury to the neobladder or other complication was noted during hernia repair. The patients were followed after hernia repair for 20, 22, and 42 months with no recurrence, mesh erosion, or other complications. Careful understanding and attention to details of the technique can minimize the risk of complications, especially incisional hernia recurrence, injury to the neobladder, and erosion of mesh into the neobladder wall

A Rare Case of Renal Gastrinoma

We present a rare case of renal gastrinoma. To the best of our knowledge, only one case of renal gastrinoma has been reported in the literature so far. An African American male was diagnosed with Zollinger Ellison syndrome at the age of 15 years, when he underwent surgery for peritonitis secondary to duodenal ulcer perforation. Further evaluation was deferred and proton pump inhibitors were prescribed. Later evaluation showed a left renal mass. Serum gastrin levels were 4,307 pg/ml. A CAT scan of the abdomen showed 4- x 4-cm heterogeneous solid mass in the interpolar region of the left kidney with central hypodensity. Somatostatin scintigraphy confirmed a receptor-positive mass in the same location. Nephrectomy was done and the tumor was diagnosed on histopathological examination as a gastrinoma. At 6-month follow-up, gastrin levels were 72 pg/ml. After a follow-up of 6 years, the patient has no recurrent symptoms

Prognostic Significance and Gene Expression Profiles of p53 Mutations in Microsatellite-Stable Stage III Colorectal Adenocarcinomas

Although the prognostic value of p53 abnormalities in Stage III microsatellite stable (MSS) colorectal cancers (CRCs) is known, the gene expression profiles specific to the p53 status in the MSS background are not known. Therefore, the current investigation has focused on identification and validation of the gene expression profiles associated with p53 mutant phenotypes in MSS Stage III CRCs. Genomic DNA extracted from 135 formalin-fixed paraffin-embedded tissues, was analyzed for microsatellite instability (MSI) and p53 mutations. Further, mRNA samples extracted from five p53-mutant and five p53-wild-type MSS-CRC snap-frozen tissues were profiled for differential gene expression by Affymetrix Human Genome U133 Plus 2.0 arrays. Differentially expressed genes were further validated by the high-throughput quantitative nuclease protection assay (qNPA), and confirmed by quantitative real-time polymerase chain reaction (qRT-PCR) and by immunohistochemistry (IHC). Survival rates were estimated by Kaplan-Meier and Cox regression analyses. A higher incidence of p53 mutations was found in MSS (58%) than in MSI (30%) phenotypes. Both univariate (log-rank, P = 0.025) and multivariate (hazard ratio, 2.52; 95% confidence interval, 1.25–5.08) analyses have demonstrated that patients with MSS-p53 mutant phenotypes had poor CRC-specific survival when compared to MSS-p53 wild-type phenotypes. Gene expression analyses identified 84 differentially expressed genes. Of 49 down-regulated genes, LPAR6, PDLIM3, and PLAT, and, of 35 up-regulated genes, TRIM29, FUT3, IQGAP3, and SLC6A8 were confirmed by qNPA, qRT-PCR, and IHC platforms. p53 mutations are associated with poor survival of patients with Stage III MSS CRCs and p53-mutant and wild-type phenotypes have distinct gene expression profiles that might be helpful in identifying aggressive subsets