Citations

OBJECTIVE—Measurement of plasma C2 glucose enrichment is cumbersome. Therefore, the plasma C5 glucose–to–2H2O rather than the plasma C5-to-C2 glucose ratio commonly has been used to measure gluconeogenesis and glycogenolysis during hyperinsulinemic-euglycemic clamps. The validity of this approach is unknown. RESEARCH DESIGN AND METHODS—Ten nondiabetic and 10 diabetic subjects ingested 2H2O the evening before study. The following morning, insulin was infused at a rate of 0.6 mU · kg−1 · min−1 and glucose was clamped at ∼5.3 mmol/l for 5 h. Plasma C5 glucose, C2 glucose, and 2H2O enrichments were measured hourly from 2 h onward. RESULTS—Plasma C2 glucose and plasma 2H2O enrichment were equal in both groups before the clamp, resulting in equivalent estimates of gluconeogenesis and glycogenolysis. In contrast, plasma C2 glucose and plasma C5 glucose enrichments fell throughout the clamp, whereas plasma 2H2O enrichment remained unchanged. Since the C5 glucose concentration and, hence, the C5 glucose–to–2H2O ratio is influenced by both gluconeogenesis and glucose clearance, whereas the C5-to-C2 glucose ratio is only influenced by gluconeogenesis, the C5 glucose–to–2H2O ratio overestimated (P < 0.01) gluconeogenesis during the clamp. This resulted in biologically implausible negative (i.e., calculated rates of gluconeogenesis exceeding total endogenous glucose production) rates of glycogenolysis in both the nondiabetic and diabetic subjects. CONCLUSIONS—Plasma C5 glucose–to–2H2O ratio does not provide an accurate assessment of gluconeogenesis in nondiabetic or diabetic subjects during a traditional (i.e., 2–3 h) hyperinsulinemic-euglycemic clamp. The conclusions of studies that have used this approach need to be reevaluated.

Abstract Metaplastic breast carcinoma, a rare tumor composed of adenocarcinomatous and nonglandular growth patterns, is characterized by a propensity for distant metastases and resistance to standard anticancer therapies. We sought confirmation that this tumor is a basal-like breast cancer, expressing epidermal growth factor receptor (EGFR) and stem cell factor receptor (KIT). EGFR activating mutations and high copy number (associated with response to tyrosine kinase inhibitor gefitinib) and KIT activating mutations (associated with imatinib sensitivity) were then investigated. Seventy-seven metaplastic cases were identified (1976-2006); 38 with tumor blocks available underwent pathologic confirmation before EGFR and KIT immunohistochemical analyses. A tissue microarray of malignant glandular and metaplastic elements was constructed and analyzed immunohistochemically for cytokeratin 5/6, estrogen receptor, progesterone receptor, and p63, and by fluorescence in situ hybridization for EGFR and HER-2/neu. DNA isolated from individual elements was assessed for EGFR and KIT activating mutations. All assessable cases were negative for estrogen receptor, progesterone receptor, and (except one) HER2. The majority were positive for cytokeratin 5/6 (58%), p63 (59%), and EGFR overexpression (66%); 24% were KIT positive. No EGFR or KIT activating mutations were present; 26% of the primary metaplastic breast carcinomas were fluorescence in situ hybridization-positive, displaying high EGFR copy number secondary to aneusomy (22%) and amplification (4%). We report here that metaplastic breast carcinoma is a basal-like breast cancer lacking EGFR and KIT activating mutations but exhibiting high EGFR copy number (primarily via aneusomy), suggesting that EGFR tyrosine kinase inhibitors should be evaluated in this molecular subset of breast carcinomas. [Mol Cancer Ther 2008;7(4):944–51]

The recent “Advanced Neuroimaging for Acute Stroke Treatment” meeting on September 7 and 8, 2007 in Washington DC, brought together stroke neurologists, neuroradiologists, emergency physicians, neuroimaging research scientists, members of the National Institute of Neurological Disorders and Stroke (NINDS), the National Institute of Biomedical Imaging and Bioengineering (NIBIB), industry representatives, and members of the US Food and Drug Administration (FDA) to discuss the role of advanced neuroimaging in acute stroke treatment. The goals of the meeting were to assess state-of-the-art practice in terms of acute stroke imaging research and to propose specific recommendations regarding: (1) the standardization of perfusion and penumbral imaging techniques, (2) the validation of the accuracy and clinical utility of imaging markers of the ischemic penumbra, (3) the validation of imaging biomarkers relevant to clinical outcomes, and (4) the creation of a central repository to achieve these goals. The present article summarizes these recommendations and examines practical steps to achieve them.

Background— Few studies have compared medium-term outcomes for drug-eluting stents (DES) and bare metal stents, and most are relatively small randomized controlled trials. Furthermore, since the introduction of DES, there has been increased use and duration of use of clopidogrel, statins, and other evidence-based therapies. The purpose of the present study was to compare outcomes for patients who underwent stenting in the eras before and after the introduction of DES. Methods and Results— New York state patients undergoing stenting in all nonfederal hospitals in the state were studied. Patients were excluded if they had a previous revascularization. Risk factors that were significant predictors of adverse outcomes were used to adjust adverse outcome rates. The study included 11 436 patients who received stents between October 1, 2002, and March 31, 2003, and 12 926 patients who underwent stenting between October 1, 2003, and March 31, 2004. Death rates, the combined end point of death and myocardial infarction (MI), nonfatal MI requiring readmission, target vessel revascularization, and target lesion revascularization were compared at 2 years. Patients in the DES era had significantly better risk-adjusted outcomes for death/MI (adjusted hazard ratio, 0.90; 95% confidence interval, 0.83 to 0.97), 9.9% versus 10.8%; nonfatal MI requiring readmission (adjusted hazard ratio, 0.86; 95% confidence interval, 0.76 to 0.97); target vessel revascularization (adjusted hazard ratio, 0.60; 95% confidence interval, 0.56 to 0.64), 11.2% versus 17.9%; and target lesion revascularization (hazard ratio, 0.55; 95% confidence interval, 0.51 to 0.59), 8.4% versus 14.7%. Conclusions— Patients in the DES era experienced lower rates of death/MI, nonfatal MI, target vessel revascularization, and target lesion revascularization, but there were no differences in the rates of death. These improvements are likely a result of increased use of clopidogrel, statins, and dual antiplatelet therapy, in addition to the introduction of DES.