Citations

Atherosclerotic renal artery stenosis has a range of manifestations depending on the severity of vascular occlusion. The aim of this study was to examine whether exceeding the limits of adaptation to reduced blood flow ultimately leads to tissue hypoxia, as determined by blood oxygen level dependent MRI. We compared 3 groups of hypertensive patients, 24 with essential hypertension, 13 with “moderate” (Doppler velocities 200–384 cm/s), and 17 with “severe” atherosclerotic renal artery stenosis (ARAS; velocities >384 cm/s and loss of functional renal tissue). Cortical and medullary blood flows and volumes were determined by multidetector computed tomography. Poststenotic kidney size and blood flow were reduced with ARAS, and tissue perfusion fell in the most severe lesions. Tissue medullary deoxyhemoglobin, as reflected by R2* values, was higher as compared with the cortex for all of the groups and did not differ between subjects with renal artery lesions and essential hypertension. By contrast, cortical R2* levels were elevated for severe ARAS (21.6±9.4 per second) as compared with either essential hypertension (17.8±2.3 per second; P <0.01) or moderate ARAS (15.7±2.1 per second; P <0.01). Changes in medullary R2* after furosemide administration tended to be blunted in severe ARAS as compared with unaffected (contralateral) kidneys. These results demonstrate that severe vascular occlusion overwhelms the capacity of the kidney to adapt to reduced blood flow, manifest as overt cortical hypoxia as measured by blood oxygen level–dependent MRI. The level of cortical hypoxia is out of proportion to the medulla and may provide a marker to identify irreversible parenchymal injury.

Abstract Purpose: Assessing impact of poor accrual on premature trial closure requires a relevant metric. We propose defining accrual sufficiency on apparent ability to address primary endpoints (PE) rather than attaining accrual targets. Experimental Design: All phase III trials open January 1, 1993, to December 31, 2002, by five U.S. oncology Clinical Trials Cooperative Groups (CTCG) were evaluated for accrual sufficiency and scientific results. Sufficient accrual included meeting accrual target, CTCGs documentation attesting adequate accrual, or conclusive results at interim analysis; insufficient accrual included poor accrual as cited closure reason or other reasons rendering a trial unable to address its primary endpoints. Closure rates based on our accrual sufficiency definition are compared with rates of meeting accrual targets and addressing the primary endpoints. A percentage of target accrual above which trials commonly answer the intended scientific question was identified to serve as an alternative to meeting full target accrual in designating accrual success. Results: Of 238 eligible trials, 158 (66%) closed with sufficient accrual. Among 80 trials with insufficient accrual, 70 (29%) closed specifically because of poor accrual. Inadequate accrual rates are overemphasized when defining accrual success solely by meeting accrual targets. Nearly 75% of trials conclusively addressed the primary endpoints with positive results in 39% of trials. Exceeding 80% of target accrual serves as a reliable proxy for answering the intended scientific question. Conclusions: Approximately one third of phase III trials closed with insufficient accrual to address the primary endpoints, primarily due to poor accrual. Defining accrual sufficiency broader than meeting accrual targets represents a fairer account of trial closures. Clin Cancer Res; 18(1); 256–62. ©2011 AACR.

OBJECTIVE To examine elevated depressive symptoms and antidepressant use in relation to diabetes incidence in the Women’s Health Initiative. RESEARCH DESIGN AND METHODS A total of 161,808 postmenopausal women were followed for over an average of 7.6 years. Hazard ratios (HRs) estimating the effects of elevated depressive symptoms and antidepressant use on newly diagnosed incident diabetes were obtained using Cox proportional hazards models adjusted for known diabetes risk factors. RESULTS Multivariable-adjusted HRs indicated an increased risk of incident diabetes with elevated baseline depressive symptoms (HR 1.13 [95% CI 1.07–1.20]) and antidepressant use (1.18 [1.10–1.28]). These associations persisted through year 3 data, in which respective adjusted HRs were 1.23 (1.09–1.39) and 1.31 (1.14–1.50). CONCLUSIONS Postmenopausal women with elevated depressive symptoms who also use antidepressants have a greater risk of developing incident diabetes. In addition, longstanding elevated depressive symptoms and recent antidepressant medication use increase the risk of incident diabetes.

Background Research on barriers to accrual has typically emphasized factors influencing participation after trial activation. Purpose We sought to identify factors influencing trial design and accrual predictions prior to trial activation associated with sufficient accrual. Methods A 30-question web-based survey was sent to the study chair and lead statistician for all 248 phase III trials open in 1993–2002 by five Clinical Trials Cooperative Groups. Questions addressed prior trial experience, trial design elements, accrual predictions, and perceived accrual influences. Accrual sufficiency categorization was derived from Clinical Trials Cooperative Group records: sufficient accrual included trials closed with complete accrual or at interim analysis, insufficient accrual included trials closed with inadequate accrual. Responses were analyzed by respondent role (study chair/lead statistician) and accrual sufficiency. Results Three hundred and nine eligible responses were included (response rate, 63%; lead statisticians, 81%; and study chairs, 45%), representing trials with sufficient (63%) and insufficient accruals (37%). Study chair seniority or lead statistician experience was not linked to accrual sufficiency. Literature review, study chair's personal experience, and expert opinion within Clinical Trials Cooperative Group most commonly influenced control arm selection. Clinical Trials Cooperative Group experience most influenced accrual predictions. These influences were not associated with accrual sufficiency. Among respondents citing accrual difficulties (41%), factors negatively influencing accrual were not consistently identified. Respondents credited three factors with positively influencing accrual: clinical relevance of study, lack of competing trials, and protocol paralleling normal practice. Limitations Perceptions of lead statisticians and study chairs may not accurately reflect accrual barriers encountered by participating physicians or patients. Survey responses may be subject to recall bias. Conclusion Consistent factors explaining poor accrual were not identified, suggesting reasons for poor accrual are not well understood and warrant further study. Alternate strategies for accrual prediction are needed since Clinical Trials Cooperative Group experience is linked to successful and unsuccessful accrual.

Atherosclerotic renal artery stenosis reduces blood flow and perfusion pressures to the poststenotic kidney producing renovascular hypertension and threatening glomerular filtration rate. Little is known regarding regional tissue oxygenation in human renovascular disease that develops slowly. We compared stenotic and contralateral kidneys regarding volume, tissue perfusion, blood flow measured by multidetector computed tomography, and blood oxygen level–dependent magnetic resonance values in the cortex and medulla in 14 patients with unilateral stenosis (mean: 71% by quantitative computed tomography) and in 14 essential hypertensive patients during 150 mEq/d of sodium intake and renin-angiotensin blockade. Stenotic kidney volume was reduced compared with the contralateral kidney (118.6±9.9 versus 155.4±13.7 mL; P <0.01), as was total blood flow (269.7±42.2 versus 383.7±49; P =0.02), mainly because of reduced cortical volume. Tissue perfusion was similar but lower than essential hypertension (1.5 versus 1.2 mL/min per milliliter; P <0.05). Blood oxygen level–dependent MR at 3 T confirmed elevated R2* values (a measure of deoxyhemoglobin) in deep medullary regions in all 3 sets of kidneys (38.9±0.7 versus cortex 17.8±0.36 s −1 ; P <0.0001). Despite reduced blood flow, R2* values did not differ between atherosclerotic and essential hypertensive kidneys, although furosemide-suppressible fall in medullary R2* was reduced in stenotic kidneys (5.7±1.8 versus 9.4±1.9 s −1 ; P <0.05). Renal venous oxygen levels from the stenotic kidney were higher than those from essential hypertensives (65.1±2.2 versus 58.1±1.2; P =0.006). These data indicate that, although stenosis reduced blood flow and volume, cortical and medullary oxygenation was preserved under these conditions.

Background and Purpose— Warfarin reduces stroke risk by approximately 60% in patients with atrial fibrillation (AF). Differences in awareness and treatment of AF may contribute to racial and geographic disparities in stroke mortality. The objective was to examine predictors of awareness of the diagnosis of AF and treatment with warfarin. Methods— RE asons for G eographic a nd R acial D ifferences in S troke (REGARDS) is a national, population-based, longitudinal study of 30 239 blacks and whites ≥45 years old with oversampling from blacks and the southeastern stroke belt states. Participants were enrolled January 2003 to October 2007. Data were collected using telephone interview, in-home evaluation, and self-administered questionnaires. The main variable of awareness of AF was defined by a positive answer to “Has a doctor or other health professional ever told you that you had atrial fibrillation?” and whether there was evidence of treatment on the basis of an in-home medications inventory. Results— From baseline electrocardiograms, 432 individuals (88 black and 344 white) had AF. Of these, 88% (360 of 409) had at least 1 additional CHADS 2 stroke risk factor and 60% (258 of 432) were aware of their AF. The odds of blacks being aware of their AF were one third that of whites (OR=0.32; 95% CI: 0.20 to 0.52). Among those aware, the odds of blacks being treated with warfarin were only one fourth as great as whites (OR=0.28; 0.13 to 0.60). Conclusion— Blacks were less likely than whites to be aware of having AF or to be treated with warfarin. Potential reasons for the racial disparity in warfarin treatment warrant further investigation.

Background and Purpose— Stroke symptoms in the absence of recognized stroke are common, but potential associated dysfunctions have not been described. Methods— We assessed quality-of-life measures using the Physical and Mental Component Summary scores of the Short Form 12 (PCS-12 and MCS-12) in the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort. Differences in mean PCS-12 and MCS-12 scores were assessed among participant groups symptoms-free (n=16 090); history of stroke symptoms but free of stroke/transient ischemic attack (n=3404); history of stroke (n=1491); and history of transient ischemic attack (n=818). Results— Participants with symptoms (but no diagnosis) had average PCS-12 scores 5.5 (95% CI: 5.2 to 5.9) points lower than those without symptoms, a difference similar to transient ischemic attack (6.0; 95% CI: 5.3 to 6.7) and over one half the effect of stroke (8.4; 95% CI: 8.0 to 9.0). MCS-12 scores were 2.7 (95% CI: 2.4 to 3.0) points lower for those with symptoms, −0.5 for transient ischemic attack (95% CI: 0.0 to −1.1), and −1.6 for stroke (95% CI: −1.2 to −2.0). Differences in demographic and vascular risk factors, health behaviors, physiological measures, and indices of socioeconomic status did not fully explain these differences. Those reporting history of weakness or numbness had larger current decrements in physical functioning, and those reporting history of inability to express themselves or understand language had larger current decrements in mental functioning. Conclusions— Individuals with clinically consistent symptoms but no stroke diagnosis have a lower quality of life than those without symptoms. The difference in physical functioning is substantial with a smaller decline in mental functioning. Apart from so-called “silent stroke,” there appear to be many individuals with possibly symptomatic cerebrovascular disease—either stroke or transient ischemic attack—who are not being diagnosed. Furthermore, these symptomatic but undiagnosed strokes may not be benign.

Recent evidence suggests that alveolar epithelial cells (AECs) may contribute to the development, propagation, and resolution of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Proinflammatory cytokines, pathogen products, and injurious mechanical ventilation are important contributors of excessive inflammatory responses in the lung. In the present study, we used cDNA microarrays to define the gene expression patterns of A549 cells (an AEC line) in the early stages of three models of pulmonary parenchymal cell activation: cells treated with tumor necrosis factor-α (TNFα) (20 ng/ml), lipopolysaccharide (LPS, 1 μg/ml), or cyclic stretch (20% elongation) for either 1 h or 4 h. Differential gene expression profiles were determined by gene array analysis. TNFα induced an inflammatory response pattern, including induction of genes for chemokines, inflammatory mediators, and cell surface membrane proteins. TNFα also increased genes related to pro- and anti-apoptotic proteins, signal transduction proteins, and transcriptional factors. TNFα further induced a group of genes that may form a negative feedback loop to silence the NFκB pathway. Stimulation of AECs with mechanical stretch changed cell morphology and activated Src protein tyrosine kinase. The combination of TNFα plus stretch enhanced or attenuated expression of multiple genes. LPS decreased microfilament polymerization but had less impact on NFκB translocation and gene expression. Results from this study indicate that AECs can tailor their response to different stimuli or/and combination of stimuli and subsequently play an important role in acute inflammatory responses in the lung.

SUMMARYMurine experimental autoimmune thyroiditis (EAT), characterized by thyroid destruction after immunization with thyroglobulin (Tg), has long been a useful model of organ-specific autoimmune disease. More recently, porcine thyroid peroxidase (pTPO) has also been shown to induce thyroiditis, but these results have not been confirmed. When (C57BL/6 × CBA)F1 mice, recently shown to be susceptible to mouse TPO-induced EAT, were immunized with plasmid DNA to human TPO (hTPO) and cytokines IL-12 or GM-CSF, significant antibody (Ab) titres were generated, but minimal thyroiditis was detected in one mouse only from the TPO + GM-CSF immunized group. However, after TPO DNA immunization of HLA-DR3 transgenic class II-deficient NOD mice, thyroiditis was present in 23% of mice injected with TPO + IL-12 or GM-CSF. We also used another marker for assessing the closeness of the model to human thyroid autoimmunity by examining the epitope profile of the anti-TPO Abs to immunodominant determinants on TPO. Remarkably, the majority of the anti-TPO Abs was directed to immunodominant regions A and B, demonstrating the close replication of the model to human autoimmunity. TPO protein immunizations of HLA-DR3 transgenic mice with recombinant hTPO did not result in thyroiditis, nor did immunization of other mice expressing HLA class II transgenes HLA-DR4 or HLA-DQ8, with differential susceptibility to Tg-induced EAT. Moreover, our efforts to duplicate exactly the experimental procedures used with pTPO also failed to induce thyroiditis. The success of hTPO plasmid DNA immunization of DR3+ mice, similar to our reports on Tg-induced thyroiditis and thyrotropin receptor DNA-induced Graves’ hyperthyroidism, underscores the importance of DR3 genes for all three major thyroid antigens, and provides another humanized model to study autoimmune thyroid disease.

SUMMARYFamilial and twin studies in Caucasians have established that the MHC class II allele HLA-DRB1*0301 (DR3) is a strong susceptibility gene in Graves’ hyperthyroid disease (GD). To determine if a DR3 transgene could help establish an animal model for GD, we expressed DR3 molecules in class II-knockout NOD mice (H2Ag7–). DR3+g7– mice were given cardiotoxin prior to immunization on weeks 0, 3 and 6 with plasmid DNA encoding human thyrotropin receptor (TSHR). Two groups of mice were also coimmunized with plasmid DNA for IL-4 or GM-CSF. Serial bleeds on weeks 8, 11 and 14 showed that approximately 20% of mice produced thyroid-stimulating antibodies (Abs), and approximately 25% had elevated T4 levels. In particular, a subset displayed both signs of hyperthyroidism, resulting in approximately 30% with some aspect of GD syndrome. Additional mice had thyroid-stimulating blocking Abs and/or TSH-binding inhibitory immunoglobulins, while most mice showed strong labelling of TSHR+ cells by flow cytometry. Interestingly, lymphocytic infiltration with thyroid damage and Abs to mouse thyroglobulin were also noted. Vector controls were uniformly negative. Thus, DR3 transgenic mice can serve as a model for GD, similar to our earlier reports that this allele is permissive for the Hashimoto's thyroiditis model induced with human thyroglobulin.