ABSTRACT After the contagion measles virus (MV) crosses the respiratory epithelium within myeloid cells that express the primary receptor signaling lymphocytic activation molecule (SLAM), it replicates briskly in SLAM-expressing cells in lymphatic organs. Later, the infection spreads to epithelia expressing nectin-4, an adherens junction protein expressed preferentially in the trachea, but how it gets there is not understood. To characterize the mechanisms of spread, we infected groups of 5 or 6 cynomolgus monkeys ( Macaca fascicularis ) with either a wild-type MV or its “N4-blind” derivative, which is unable to enter nectin-4-expressing cells because of the targeted mutation of two hemagglutinin residues. As expected, both viruses caused similar levels of immunosuppression, as monitored by reductions in white blood cell counts and lymphocyte proliferation activity. However, monkeys infected with the N4-blind MV cleared infection more rapidly. Wild-type virus-infected monkeys secreted virus, while marginal virus titers were detected in tracheal lavage fluid cells of N4-blind MV-infected hosts. Analyses of tracheal rings obtained at necropsy (day 12) documented widespread infection of individual cells or small cell clusters in the subepithelial lamina propria of monkeys infected with either virus. However, only wild-type MV spread to the epithelium, forming numerous infectious centers comprised of many contiguous columnar cells. Infected CD11c + myeloid (macrophage or dendritic) cells were frequently observed in the lamina propria below epithelial infectious centers. Thus, MV may use myeloid cells as vehicles not only immediately after contagion but also to infect epithelia of tissues expressing nectin-4, including the trachea.
Esophageal self-expandable stent material and mesh grid density are the major determining factors of external beam radiation dose perturbation: results from a phantom model
Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature | December 19, 2012 | Volume: No volume available | Issue: No issue available | Pages: No page available
Background— Congestion is a primary driver of symptoms in patients with acute heart failure, and relief of congestion is a critical goal of therapy. Monitoring of response to therapy through the assessment of daily weights and net fluid loss is the current standard of care, yet the relationship between commonly used markers of decongestion and both patient reported symptom relief and clinical outcomes are unknown. Methods and Results— We performed a retrospective analysis of the randomized clinical trial, Diuretic Optimization Strategy Evaluation in Acute Heart Failure (DOSE-AHF), enrolling patients hospitalized with a diagnosis of acute decompensated heart failure. We assessed the relationship among 3 markers of decongestion at 72 hours—weight loss, net fluid loss, and percent reduction in serum N terminal B-type natriuretic peptide (NT-proBNP) level—and relief of symptoms as defined by the dyspnea visual analog scale area under the curve. We also determined the relationship between each marker of decongestion and 60-day clinical outcomes defined as time to death, first rehospitalization or emergency department visit. Mean age was 66 years, mean ejection fraction was 35%, and 27% had ejection fraction ≥50%. Of the 3 measures of decongestion assessed, only percent reduction in NT-proBNP was significantly associated with symptom relief ( r =0.13; P =0.04). There was no correlation between either weight loss or net fluid loss and symptom relief, ( r =0.04; P =0.54 and r =0.07; P =0.27, respectively). Favorable changes in each of the 3 markers of decongestion were associated with improvement in time to death, rehospitalization, or emergency department visit at 60 days (weight: hazard ratio, 0.91; 95% confidence interval, 0.85–0.97 per 4 lbs; weight lost; fluid hazard ratio, 0.94; 95% confidence interval, 0.90–0.99 per 1000 mL fluid loss; NT-proBNP hazard ratio, 0.95; 95% confidence interval, 0.91–0.99 per 10% reduction). These associations were unchanged after multivariable adjustment with the exception that percent reduction in NT-proBNP was no longer a significant predictor (hazard ratio, 0.97; 95% confidence interval, 0.93–1.02). The rates of death, HF hospitalization, or emergency department visit at 60 days for patients with 0, 1, 2, and 3 markers of decongestion (above the median) were 67%, 64%, 46%, and 38%, respectively (log rank P value=0.05). Figure. Relationship between number of markers of decongestion above median* and time to 60-day risk of emergency department (ED) visit, rehospitalization, or death. *Median net fluid loss, 3.8 L; median net weight loss, 6.5 lbs; median percent reduction in N terminal B-type natriuretic peptide 24.3%. Conclusions— Weight loss, fluid loss, and NT-proBNP reduction at 72 hours are poorly correlated with dyspnea relief. However, favorable improvements in each of the 3 markers were associated with improved clinical outcomes at 60 days. These data suggest the need for ongoing research to understand the relationships among symptom relief, congestion, and outcomes in patients with acute decompensated heart failure. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00577135.
An Early Appointment to Outpatient Cardiac Rehabilitation at Hospital Discharge Improves Attendance at Orientation
Background— Outpatient cardiac rehabilitation (CR) decreases mortality rates but is underutilized. Current median time from hospital discharge to enrollment is 35 days. We hypothesized that an appointment within 10 days would improve attendance at CR orientation. Methods and Results— At hospital discharge, 148 patients with a nonsurgical qualifying diagnosis for CR were randomized to receive a CR orientation appointment either within 10 days (early) or at 35 days (standard). The primary end point was attendance at CR orientation. Secondary outcome measures were attendance at ≥1 exercise session, the total number of exercise sessions attended, completion of CR, and change in exercise training workload while in CR. Average age was 60±12 years; 56% of participants were male and 49% were black, with balanced baseline characteristics between groups. Median time (95% confidence interval) to orientation was 8.5 (7–13) versus 42 (35 to NA [not applicable]) days for the early and standard appointment groups, respectively ( P <0.001). Attendance rates at the orientation session were 77% (57/74) versus 59% (44/74) in the early and standard appointment groups, respectively, which demonstrates a significant 18% absolute and 56% relative improvement (relative risk, 1.56; 95% confidence interval, 1.03–2.37; P =0.022). The number needed to treat was 5.7. There was no difference ( P >0.05) in any of the secondary outcome measures, but statistical power for these end points was low. Safety analysis demonstrated no difference between groups in CR-related adverse events. Conclusions— Early appointments for CR significantly improve attendance at orientation. This simple technique could potentially increase initial CR participation nationwide. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT01596036.
The Effect of a Bile Acid Sequestrant on Glucose Metabolism in Subjects With Type 2 Diabetes
We designed an experiment to examine the effect of bile acid sequestration with Colesevelam on fasting and postprandial glucose metabolism in type 2 diabetes. To do so, we tested the hypothesis that Colesevelam increases the disposition index (DI), and this increase is associated with increased glucagon-like peptide-1 (GLP-1) concentrations. Thirty-eight subjects on metformin monotherapy were studied using a double-blind, placebo-controlled, parallel-group design. Subjects were studied before and after 12 weeks of Colesevelam or placebo using a labeled triple-tracer mixed meal to measure the rate of meal appearance (Meal Ra), endogenous glucose production (EGP), and glucose disappearance (Rd). Insulin sensitivity and β-cell responsivity indices were estimated using the oral minimal model and then used to calculate DI. Therapy with Colesevelam was associated with a decrease in fasting (7.0 ± 0.2 vs. 6.6 ± 0.2 mmol/L; P = 0.004) and postprandial glucose concentrations (3,145 ± 138 vs. 2,896 ± 127 mmol/6 h; P = 0.01) in the absence of a change in insulin concentrations. Minimal model–derived indices of insulin secretion and action were unchanged. Postprandial GLP-1 concentrations were not altered by Colesevelam. Although EGP and Rd were unchanged, integrated Meal Ra was decreased by Colesevelam (5,191 ± 204 vs. 5,817 ± 204 μmol/kg/6 h; P = 0.04), suggesting increased splanchnic sequestration of meal-derived glucose.