Citations

Abstract Background: Urinary albumin excretion is a sensitive diagnostic and prognostic marker for renal disease. Therefore, measurement of urinary albumin must be accurate and precise. We have developed a method to quantify intact urinary albumin with a low limit of quantification (LOQ). Methods: We constructed an external calibration curve using purified human serum albumin (HSA) added to a charcoal-stripped urine matrix. We then added an internal standard, 15N-labeled recombinant HSA (15NrHSA), to the calibrators, controls, and patient urine samples. The samples were reduced, alkylated, and digested with trypsin. The concentration of albumin in each sample was determined by liquid chromatography–tandem mass spectrometry (LC-MS/MS) and linear regression analysis, in which the relative abundance area ratio of the tryptic peptides 42LVNEVTEFAK51 and 526QTALVELVK534 from albumin and 15NrHSA were referenced to the calibration curve. Results: The lower limit of quantification was 3.13 mg/L, and the linear dynamic range was 3.13–200 mg/L. Replicate digests from low, medium, and high controls (n = 5) gave intraassay imprecision CVs of 2.8%–11.0% for the peptide 42LVNEVTEFAK51, and 1.9%–12.3% for the 526QTALVELVK534 peptide. Interassay imprecision of the controls for a period of 10 consecutive days (n = 10) yielded CVs of 1.5%–14.8% for the 42LVNEVTEFAK51 peptide, and 6.4%–14.1% for the 526QTALVELVK534 peptide. For the 42LVNEVTEFAK51 peptide, a method comparison between LC-MS/MS and an immunoturbidometric method for 138 patient samples gave an R2 value of 0.97 and a regression line of y = 0.99x + 23.16. Conclusions: Urinary albumin can be quantified by a protein cleavage LC-MS/MS method using a 15NrHSA internal standard. This method provides improved analytical performance in the clinically relevant range compared to a commercially available immunoturbidometric assay.

Abstract Family history is a strong predictor of colorectal cancer risk; however, a diagnosis of colorectal cancer among first-degree relatives has not been systematically investigated as a function of the colorectal cancer molecular subtypes related to tumor microsatellite instability (MSI) status. We investigated whether the observable familial colorectal cancer risks differed according to tumor MSI subtypes, stratified as MSI-High (>30% instability), MSI-Low (<30% instability), and MSS (no instability). Data from 3,143 population-based colorectal cancer cases from five institutions were assessed for family history according to the Amsterdam criteria and the Bethesda guidelines, age at diagnosis, sex, tumor location, and MSI status. The distribution of patient characteristics by MSI status was compared using polytomous logistic regression. Overall, 2.8% colorectal cancer cases met the Amsterdam criteria and 37% met the Bethesda guidelines. There were 14% MSI-High, 13% MSI-Low, and 73% MSS colorectal cancers. MSI-High (P < 0.0001) and MSI-Low tumors (P = 0.01) were more proximally located than MSS tumors. MSI-High tumors were more common among females (P < 0.001). The highest proportion of MSI-High tumors occurred in cases <40 years of age whereas the age-dependent distribution of MSI-Low tumors was unchanged. MSI-High tumors showed a statistically significant association with increasing numbers of first-degree relatives with colorectal cancer (P = 0.002); this association disappeared, however, when MSI-High cases meeting Amsterdam criteria were removed from the analysis. MSI-Low tumors did not show a similar association with family history of colorectal cancer. Familial risk associated with MSI-High tumors is primarily driven by the Amsterdam-criteria patients. MSI-Low tumors may represent a distinct subtype of colorectal cancer with respect to certain epidemiologic variables studied here. (Cancer Epidemiol Biomarkers Prev 2009;18(3):967–75)

Background Paraplegia is a devastating complication for patients undergoing repair of thoracoabdominal aortic aneurysms. A monitor to detect spinal cord ischemia is necessary if anesthesiologists are to intervene to protect the spinal cord during aortic aneurysm clamping. Methods The medical records of 60 patients who underwent thoracoabdominal aortic aneurysm repair with regional lumbar epidural cooling with evoked potential monitoring were reviewed. The authors analyzed latency and amplitude of motor evoked potentials, somatosensory evoked potentials, and H reflexes before cooling and clamping, after cooling and before clamping, during clamping, and after release of aortic cross clamp. Results Twenty minutes after the aortic cross clamp was placed, motor evoked potentials had 88% sensitivity and 65% specificity in predicting spinal cord ischemia. The negative predictive value of motor evoked potentials at 20 min after aortic cross clamping was 96%. Conclusions Rapid loss of motor evoked potentials or H reflexes after application of the aortic cross clamp identifies a subgroup of patients who are at high risk of developing spinal cord ischemia and in whom aggressive anesthetic and surgical interventions may be justified.

PurposeSmudge cells are ruptured chronic lymphocytic leukemia (CLL) cells appearing on the blood smears of CLL patients. Our recent findings suggest that the number of smudge cells may have important biologic correlations rather than being only an artifact of slide preparation. In this study, we evaluated whether the smudge cell percentage on a blood smear predicted survival of CLL patients.Patients and MethodsWe calculated smudge cell percentages (ratio of smudged to intact cells plus smudged lymphocytes) on archived blood smears from a cohort of previously untreated patients with predominantly early-stage CLL enrolled onto a prospective observational study. The relationship between percentage of smudge cells, patient survival, and other prognostic factors was explored.ResultsBetween 1994 and 2002, 108 patients were enrolled onto the study and had archived blood smears available for review; 80% of patients had Rai stage 0 or I disease. The median smudge cell percentage was 28% (range, 1% to 75%). The percentage of smudge cells was lower in CD38+versus CD38–patients (P = .019) and in Zap70-positive versus Zap70-negative patients (P = .028). Smudge cell percentage as a continuous variable was associated with prolonged survival (P = .042). The 10-year survival rate was 50% for patients with 30% or less smudge cells compared with 80% for patients with more than 30% of smudge cells (P = .015). In multivariate analysis, the percentage of smudge cells was an independent predictor of overall survival.ConclusionPercentage of smudge cells on blood smear is readily available and an independent factor predicting overall survival in CLL.

Among young normotensive men, a reciprocal balance between cardiac output and sympathetic nerve activity is important in the regulation of arterial pressure. In young women, the balance among cardiac output, peripheral resistance, and sympathetic nerve activity is unknown. Consequently, the aim of this study was to examine the relationship of cardiac output and total peripheral resistance to muscle sympathetic nerve activity in young women. Multiunit peroneal recordings of muscle sympathetic nerve activity were obtained in 17 women (mean±SEM: age 24±3 years) and 21 men (mean±SEM: age 25±5 years). Mean resting muscle sympathetic nerve activity was lower in women compared with men (19±3 versus 25±1 bursts minute −1 ; P <0.05), as was mean arterial pressure (89±1 versus 94±2 mm Hg; P <0.05). Mean arterial pressure was not related to muscle sympathetic nerve activity in men ( P =0.80) or women ( P =0.62). There was a positive relationship between total peripheral resistance and muscle sympathetic nerve activity ( r =0.62; P <0.05) and an inverse relationship between cardiac output and muscle sympathetic nerve activity ( r =−0.69; P <0.05) in men. Unexpectedly, muscle sympathetic nerve activity had no relationship to either total peripheral resistance ( r =−0.27; P >0.05) or cardiac output ( r =0.23; P >0.05) in women. Our results demonstrate that men and women rely on different integrated physiological mechanisms to maintain a normal arterial pressure despite widely varying sympathetic nerve activity among individuals. These findings may have important implications for understanding how hypertension and other disorders of blood pressure regulation occur in men and women.

Abstract Purpose: The goals of this study were (a) to investigate whether preconditioning of immunocompetent mice with PC-61-mediated regulatory T-cell (Treg) depletion and interleukin-2 (IL-2) would enhance systemic delivery of reovirus into subcutaneous tumors and (b) to test whether cyclophosphamide (CPA), which is clinically approved, could mimic PC-61 for modification of Treg activity for translation into the next generation of clinical trials for intravenous delivery of reovirus. Experimental Design: C57Bl/6 mice bearing subcutaneous B16 tumors were treated with CPA or PC-61 followed by 10 injections of low-dose IL-2. Mice were then treated with intravenous reovirus. Virus localization to tumor and other organs was measured along with tumor growth and systemic toxicity. Results: Preconditioning with PC-61 and IL-2 enhanced localization of intravenous oncolytic reovirus to tumors with significantly increased antitumor therapy compared with controls (P &lt; 0.01). However, with the maximal achievable dose of reovirus, Treg modification + IL-2 was also associated with systemic toxicity. CPA (100 mg/kg) did not deplete, but did functionally inhibit, Treg. CPA also mimicked PC-61, in combination with IL-2, by inducing “hyperactivated” NK cells. Consistent with this, preconditioning with CPA + IL-2 enhanced therapy of intravenously delivered, intermediate-dose reovirus to a level indistinguishable from that induced by PC-61 + IL-2, without any detectable toxicity. Conclusion: With careful reference to ongoing clinical trials with dose escalation of reovirus alone and in combination with CPA, we propose that future clinical trials of CPA + IL-2 + reovirus will allow for both improved levels of virus delivery and increased antitumor efficacy.