Citations

Abstract Purpose: Colon tumors with defective DNA mismatch repair (dMMR) have a well-characterized phenotype and accounts for ∼15% to 20% of sporadic colon cancer as well as those colon cancer patients with Lynch syndrome. Although the presence of dMMR seems to be a favorable prognostic marker, data suggest that these patients do not respond as well to adjuvant chemotherapy. Experimental Design: In this study, we examined the prognostic significance of tumor MMR deficiency and the presence of a specific mutation in BRAF (V600E) in a group of patients (n = 533) who participated in a randomized prospective clinical trial through the North Central Cancer Treatment Group. Results: Tumors with dMMR were found to be associated with higher tumor grade (P = 0.001), proximal location (P < 0.0001), and improved overall and disease-free survival (P = 0.05 and 0.04, respectively). Among all cases examined, evaluation of the BRAF V600E mutation status revealed no statistically significant differences in either disease-free or overall survival. Patients were then grouped into four categories for further analysis: dMMR/BRAF(−), dMMR/BRAF(+), pMMR/BRAF(−), and pMMR/BRAF(+). The dMMR/BRAF(−) group had a significantly improved overall survival (5-year overall survival of 100% versus 73%, P = 0.002) compared with all others. The remaining three groups had very similar survival outcomes. An additional cohort of tumors previously classified as having dMMR were also tested for the BRAF V600E alteration. Results remained significant (P = 0.006) when the two groups were combined for analysis. Conclusions: Overall, these data suggest that the underlying molecular etiology of those tumors having dMMR may influence the disease outcome in these patients.

Abstract Background: We evaluated the sensitivity, precision, and concordance of 4 assays designed to detect aspirin responsiveness or resistance. Methods: Twenty-nine healthy laboratory volunteers took 80 mg aspirin for 7 days, and a subset of volunteers took 325 mg aspirin for an additional 7 days. We measured platelet function by light transmission aggregometry with arachidonic acid, PFA-100, and VerifyNow. PFA-100 and VerifyNow assays were performed in duplicate to assess method imprecision. Some volunteers had samples taken within 2–4 h of the final dose of aspirin and again within 20–24 h of the final dose. We measured urinary 11-dehydro-thromboxane B2 at baseline and after 80 or 325 mg aspirin. Results: No volunteers were nonresponsive to aspirin therapy as measured by the PFA-100. One of 29 participants demonstrated lack of response to aspirin as measured by VerifyNow and urinary 11-dehydro-thromboxane B2; 2 of 29 demonstrated lack of response as measured by light transmission aggregometry. Imprecision was <10% for the PFA-100 and VerifyNow. Concordance was high (>90%) between all assays. Neither aspirin dose (80 vs 325 mg) nor timing between final dose of aspirin and blood draw (2–4 vs 20–24 h) affected any of the assays. Conclusions: Light transmission aggregometry, PFA-100, VerifyNow, and urinary 11-dehydro-thromboxane B2 are all sensitive to the effects of aspirin in healthy individuals. Variables such as aspirin dose, timing between final dose of aspirin and blood collection, and imprecision do not affect the ability of the assays to detect aspirin effect on platelet function.

Background: Previous studies that have attempted to evaluate the effectiveness of an iso-osmolar contrast medium (IOCM) iodixanol compared to a low-osmolar contrast medium (LOCM) for contrast procedures show variable results. Purpose: To evaluate the nephrotoxicity of the IOCM iodixanol compared to the LOCM iohexol. Material and Methods: We performed a retrospective cohort study from April 2004 to March 2006. All contrast procedures with a pre- and post-exposure creatinine value were evaluated for inclusion. Contrast nephropathy (CN) was defined as post-exposure creatinine elevation of ≥25% or >0.5 mg/dl within 7 days of contrast exposure. Cases of iodixanol exposure were matched to control cases of iohexol exposure (1:1) based on age, sex, presence of diabetes, pre-exposure creatinine value, and type of imaging study performed. We matched 397 cases of iodixanol (IOCM) exposure to 397 cases of iohexol (LOCM) exposure. Cases of iodixanol which could not be matched to controls were not included in the analysis. Results: After adjustment for prior creatinine, medications, contrast iodine load, prior exposure to contrast material, heart failure, and hypertension, use of iodixanol did not significantly alter rates of CN compared to iohexol (OR 0.92, 95% CI 0.57–1.46; P=0.71) or mortality (RR 0.79, 95% CI 0.59–1.06; P=0.12). Conclusion: The use of the IOCM iodixanol was not associated with statistically significant protection against contrast nephropathy or all-cause mortality compared to a matched cohort of patients receiving the LOCM iohexol.

Background Isolated meniscal tears in the skeletally immature patient are infrequent but well-recognized injuries. Although few studies have evaluated the pediatric and adolescent population, arthroscopic surgical repair remains the standard of care for Patients in this age group with unstable meniscal tears. Purpose To review our results of arthroscopic repair of isolated meniscal tears in pediatric and adolescent patients to further define future management of these injuries. Study Design Case series; Level of evidence, 4. Methods The records of all patients 18 years old or younger who underwent isolated meniscal repair between 1990 and 2005 were retrospectively reviewed. Forty-four patients (6 girls, 38 boys) with an average age of 15.8 years (range, 9.9-18.7 years) were included in this study, for a total of 45 isolated meniscal tears. Clinical examinations were performed, International Knee Documentation Committee forms were administered, and Tegner scores were determined at an average of 5.8 years (range, 2.5 months-13.8 years) postoperative follow-up. Three patients were lost to follow-up. Results The clinical success rate of arthroscopic meniscal repair was 80% for simple tears, 68% for displaced bucket-handle tears, and 13% for complex tears. Seventeen menisci (38% overall) failed initial repair at a mean of 17 months (range, 3-61 Months) postoperatively and underwent repeat arthroscopic surgery (15 partial meniscectomies, 2 rerepair). The average Tegner and International Knee Documentation Committee scores were 8 (range, 5-9) and 89.4 (range, 79-99), respectively, at the time of final follow-up. Risk factors for failure included complex tears and rim width greater than 3 mm. Conclusion Clinically successful repair of an isolated meniscal tear in patients 18 years or younger was variable depending on tear type, with complex tears and rim width 3 mm or greater being negative prognostic factors.

OBJECTIVETo review the Mayo Clinic experience with sinonasal melanoma.STUDY DESIGNRetrospective review (case series).SUBJECTS AND METHODSWe identified 61 patients who had melanoma arising from the nasal cavity, paranasal sinuses, or both. All were treated at our institution from 1955 through 2003. Clinical and pathologic data were summarized, and survival curves were generated.RESULTSThe most common symptoms at presentation were epistaxis and nasal congestion. The most common treatment was excision only (48%). The cancer‐specific survival rate (ie, rate of death due to disease) was 48.9% and 22.1% at 3 and 5 years, respectively. Median time between diagnosis and death due to disease was 19 months.CONCLUSIONSinonasal melanoma is a rare but devastating disease. Wide local excision is the treatment of choice, and some patients may benefit from postoperative radiotherapy. Local recurrence and distant metastasis are common. Improved survival depends on better systemic therapies.

The Drosophila immune deficiency (IMD) pathway, homologous to the mammalian tumor necrosis factor (TNF‐α) signaling pathway, initiates antimicrobial peptide (AMP) production in response to infection by gram‐negative bacteria. A membrane‐spanning peptidoglycan recognition protein, PGRP‐LC, functions as the receptor for the IMD pathway. This receptor is activated via pattern recognition and binding of monomeric peptidoglycan (DAP‐type PGN) through the PGRP ectodomain. In this article, we show that the receptor PGRP‐LC is down‐regulated in response to Salmonella/Escherichia coli infection but is not affected by Staphylococcus infection in vivo, and an ectodomain‐deleted PGRP‐LC lacking the PGRP domain is an active receptor. We show that the receptor PGRP‐LC regulates and integrates two host defense systems: the AMP production and melanization. A working model is proposed in which pathogen invasion and tissue damage may be monitored through the receptor integrity of PGRP‐LC after host and pathogen are engaged via pattern recognition. The irreversible cleavage or down‐regulation of PGRP‐LC may provide an additional cue for the host to distinguish pathogenic microbes from nonpathogenic ones and to subsequently activate multiple host defense systems in Dro‐sophila, thereby effectively combating bacterial infection and initiating tissue repair.—Schmidt, R. L., Trejo, T. R., Plummer, T. B., Platt, J. L., Tang, A. H. Infection‐induced proteolysis of PGRP‐LC controls the IMD activation and melanization cascades in Drosophila. FASEB J . 22, 918–929 (2008)