Human-relevant potency threshold (HRPT) for ERα agonism.

The European Commission has recently proposed draft criteria for the identification of endocrine disrupting chemicals (EDCs) that pose a significant hazard to humans or the environment. Identifying and characterizing toxic hazards based on the manner by which adverse effects are produced rather than on the nature of those adverse effects departs from traditional practice and requires a proper interpretation of the evidence regarding the chemical's ability to produce physiological effect(s) via a specific mode of action (MoA). The ability of any chemical to produce a physiological effect depends on its pharmacokinetics and the potency by which it acts via the various MoAs that can lead to the particular effect. A chemical's potency for a specific MoA-its mechanistic potency-is determined by two properties: (1) its affinity for the functional components that comprise the MoA, i.e., its specific receptors, enzymes, transporters, transcriptional elements, etc., and (2) its ability to alter the functional state of those components (activity). Using the agonist MoA via estrogen receptor alpha, we illustrate an empirical method for determining a human-relevant potency threshold (HRPT), defined as the minimum level of mechanistic potency necessary for a chemical to be able to act via a particular MoA in humans. One important use for an HRPT is to distinguish between chemicals that may be capable of, versus those likely to be incapable of, producing adverse effects in humans via the specified MoA. The method involves comparing chemicals that have different ERα agonist potencies with the ability of those chemicals to produce ERα-mediated agonist responses in human clinical trials. Based on this approach, we propose an HRPT for ERα agonism of 1E-04 relative to the potency of the endogenous estrogenic hormone 17ß-estradiol or the pharmaceutical estrogen, 17α-ethinylestradiol. This approach provides a practical way to address Hazard Identification according to the draft criteria for identification of EDCs recently proposed by the European Commission.

Computer-assisted image processing 12 lead ECG model to diagnose hyperkalemia.

BACKGROUND: We sought to develop an improved 12 lead ECG model to diagnose hyperkalemia by use of traditional and novel parameters. METHODS: We retrospectively analyzed ECGs in consecutive hyperkalemic patients (serum potassium (K)>5.3mEq/L) by blinded investigators with normokalemic ECGs as internal controls. Potassium levels were modeled using general linear mixed models followed by refit with standardized variables. Optimum sensitivity and specificity were determined using cut point analysis of ROC-AUC. RESULTS: The training set included 236 ECGs (84 patients) and validation set 97 ECGs (23 patients). Predicted K=(5.2354)+(0.03434*descending T slope)+(-0.2329*T width)+(-0.9652*reciprocal of new QRS width>100msec). ROC-AUC in the validation set was 0.78 (95% CI 0.69-0.88). Maximum specificity of the model was 84% for K>5.91 with sensitivity of 63%. CONCLUSION: ECG model incorporating T-wave width, descending T-wave slope and new QRS prolongation improved hyperkalemia diagnosis over traditional ECG analysis.

Comparison of a self-inflating bulb syringe and a colorimetric CO2 indicator with capnography and radiography to detect the misdirection of naso/orogastric tubes into the airway of critically ill adult patients.

OBJECTIVE: The objective of this study was to develop a mechanism of discovering misdirection into the airway of naso/orogastric (NG) tubes before they reach their full depth of placement in adults. METHODS: A prospective, observational study was performed in humans, evaluating both the self-inflating bulb syringe (SIBS) and a colorimetric CO2 detector. A prospective convenience sample of 257 NG tube placements was studied in 199 patients in medical ICUs of a tertiary care medical center. Findings were compared to a "standard" (ie, end tidal CO2 results of a capnograph and the results of a chest radiograph performed at the completion of the tube placement). RESULTS: On the first tube placement attempt in any patient, the SIBS had a sensitivity of 91.5% and a specificity of 87.0% in detecting nonesophageal placement, while the colorimetric device exhibited 99.4% sensitivity and 91.3% specificity. On subsequent insertions, the SIBS showed 95.7% sensitivity and 100% specificity, while the colorimetric device exhibited 97.8% sensitivity and 100% specificity. The colorimetric device was eight times more expensive than the SIBS. CONCLUSIONS: The SIBS and the colorimetric CO2 detector are very good at detecting NG tube malpositioning into the airway, although the colorimetric device is slightly more sensitive and specific. Neither method adds substantial time or difficulty to the insertion process. The colorimetric device is substantially more expensive. The decision as to which method to use may be based on local institutional factors, such as expense.

Spatial re-organization of myogenic regulatory sequences temporally controls gene expression.

During skeletal muscle differentiation, the activation of some tissue-specific genes occurs immediately while others are delayed. The molecular basis controlling temporal gene regulation is poorly understood. We show that the regulatory sequences, but not other regions of genes expressed at late times of myogenesis, are in close physical proximity in differentiating embryonic tissue and in differentiating culture cells, despite these genes being located on different chromosomes. Formation of these inter-chromosomal interactions requires the lineage-determinant MyoD and functional Brg1, the ATPase subunit of SWI/SNF chromatin remodeling enzymes. Ectopic expression of myogenin and a specific Mef2 isoform induced myogenic differentiation without activating endogenous MyoD expression. Under these conditions, the regulatory sequences of late gene loci were not in close proximity, and these genes were prematurely activated. The data indicate that the spatial organization of late genes contributes to temporal regulation of myogenic transcription by restricting late gene expression during the early stages of myogenesis.

The bundle "plus": the effect of a multidisciplinary team approach to eradicate central line-associated bloodstream infections.

BACKGROUND: Central line-associated bloodstream infections (CLABSIs) have decreased significantly over the last decade. Further reductions in CLABSI rates should be possible. We describe a multidisciplinary approach to the reduction of CLABSIs. METHODS: This was an observational study of critically ill patients requiring central venous catheters in 8 intensive care units in a tertiary medical center. We implemented a catheter bundle that included hand hygiene, education of providers, chlorhexidine skin preparation, use of maximum barrier precautions, a dedicated line cart, checklist, avoidance of the femoral vein for catheter insertion, chlorhexidine-impregnated dressings, use of anti-infective catheters, and daily consideration of the need for the catheter. Additional measures included root cause analyses of all CLABSIs, creation of a best practice atlas for internal jugular catheters, and enhanced education on blood culture collection. Data were analyzed using the Poisson test and regression. RESULTS: CLABSI, catheter use, and microbiology were tracked from 2004 to 2012. There was a 92% reduction in CLABSIs (95% lower confidence limit: 67.4% reduction, P < 0.0001). Central venous catheter use decreased significantly from 2008 to 2012 (P = 0.032, -151 catheters per year, 95% confidence limits: -277 to -25), whereas peripherally inserted central catheter use increased (P = 0.005, 89 catheters per year, 95% confidence limits: 50 to 127). There was no apparent association between unit-specific Acute Physiology And Chronic Health Evaluation III/IV scores and CLABSI. Three units have not had a CLABSI in more than a year. The most common organism isolated was coagulase-negative staphylococcus. Since the implementation of minocycline/rifampin catheters, no cases of methicillin-resistant Staphylococcus aureus CLABSI have occurred. CONCLUSIONS: The implementation of a standard catheter bundle combined with chlorhexidine dressings, minocycline/rifampin catheters, and other behavioral changes was associated with a sustained reduction in CLABSIs.

Prevalence and test characteristics of national health safety network ventilator-associated events.

OBJECTIVES: The primary aim of the study was to measure the test characteristics of the National Health Safety Network ventilator-associated event/ventilator-associated condition constructs for detecting ventilator-associated pneumonia. Its secondary aims were to report the clinical features of patients with National Health Safety Network ventilator-associated event/ventilator-associated condition, measure costs of surveillance, and its susceptibility to manipulation. DESIGN: Prospective cohort study. SETTING: Two inpatient campuses of an academic medical center. PATIENTS: Eight thousand four hundred eight mechanically ventilated adults discharged from an ICU. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The National Health Safety Network ventilator-associated event/ventilator-associated condition constructs detected less than a third of ventilator-associated pneumonia cases with a sensitivity of 0.325 and a positive predictive value of 0.07. Most National Health Safety Network ventilator-associated event/ventilator-associated condition cases (93%) did not have ventilator-associated pneumonia or other hospital-acquired complications; 71% met the definition for acute respiratory distress syndrome. Similarly, most patients with National Health Safety Network probable ventilator-associated pneumonia did not have ventilator-associated pneumonia because radiographic criteria were not met. National Health Safety Network ventilator-associated event/ventilator-associated condition rates were reduced 93% by an unsophisticated manipulation of ventilator management protocols. CONCLUSIONS: The National Health Safety Network ventilator-associated event/ventilator-associated condition constructs failed to detect many patients who had ventilator-associated pneumonia, detected many cases that did not have a hospital complication, and were susceptible to manipulation. National Health Safety Network ventilator-associated event/ventilator-associated condition surveillance did not perform as well as ventilator-associated pneumonia surveillance and had several undesirable characteristics.

A multicenter study of ICU telemedicine reengineering of adult critical care.

BACKGROUND: Few studies have evaluated both the overall effect of ICU telemedicine programs and the effect of individual components of the intervention on clinical outcomes. METHODS: The effects of nonrandomized ICU telemedicine interventions on crude and adjusted mortality and length of stay (LOS) were measured. Additionally, individual intervention components related to process and setting of care were evaluated for their association with mortality and LOS. RESULTS: Overall, 118,990 adult patients (11,558 control subjects, 107,432 intervention group patients) from 56 ICUs in 32 hospitals from 19 US health-care systems were included. After statistical adjustment, hospital (hazard ratio [HR]=0.84; 95% CI, 0.78-0.89; P<.001) and ICU (HR=0.74; 95% CI, 0.68-0.79; P<.001) mortality in the ICU telemedicine intervention group was significantly better than that of control subjects. Moreover, adjusted hospital LOS was reduced, on average, by 0.5 (95% CI, 0.4-0.5), 1.0 (95% CI, 0.7-1.3), and 3.6 (95% CI, 2.3-4.8) days, and adjusted ICU LOS was reduced by 1.1 (95% CI, 0.8-1.4), 2.5 (95% CI, 1.6-3.4), and 4.5 (95% CI, 1.5-7.2) days among those who stayed in the ICU for ≥7, ≥14, and ≥30 days, respectively. Individual components of the interventions that were associated with lower mortality, reduced LOS, or both included (1) intensivist case review within 1 h of admission, (2) timely use of performance data, (3) adherence to ICU best practices, and (4) quicker alert response times. CONCLUSIONS: ICU telemedicine interventions, specifically interventions that increase early intensivist case involvement, improve adherence to ICU best practices, reduce response times to alarms, and encourage the use of performance data, were associated with lower mortality and LOS.

Effect of linker length and composition on heterobivalent ligand-mediated receptor cross-talk between the A1 adenosine and ß2 adrenergic receptors.

Heterobivalent ligands that possess pharmacophores designed to interact with both the A1 adenosine receptor (A1 AR) and the ß2 adrenergic receptor (ß2 AR) were prepared. More specifically, these ligands contain an adenosine moiety that is linked via its N(6) -position to the amino group of the saligenin-substituted ethanolamine moiety present in the well-known ß2 AR agonist, salbutamol. The affinities of these ligands were determined at both receptors and found to vary with linker length and composition. With all compounds, affinity and functional potencies were found to have selectivity for the A1 AR over the ß2 AR. In all cases, cAMP accumulation (a ß2 AR-mediated response) was mainly observed when the A1 AR was blocked or its function decreased by pertussis toxin or chronic agonist treatment. This suggests that heterobivalent compounds for receptors that mediate opposite responses might be useful for elucidating the mechanisms of receptor cross-talk and how this interaction, in terms of responsiveness, may change under pathophysiological conditions.

Potency matters: thresholds govern endocrine activity.

Whether thresholds exist for endocrine active substances and for endocrine disrupting effects of exogenous chemicals has been posed as a question for regulatory policy by the European Union. This question arises from a concern that the endocrine system is too complex to allow estimations of safe levels of exposure to any chemical with potential endocrine activity, and a belief that any such chemical can augment, retard, or disrupt the normal background activity of endogenous hormones. However, vital signaling functions of the endocrine system require it to continuously discriminate the biological information conveyed by potent endogenous hormones from a more concentrated background of structurally similar, endogenous molecules with low hormonal potential. This obligatory ability to discriminate important hormonal signals from background noise can be used to define thresholds for induction of hormonal effects, without which normal physiological functions would be impossible. From such thresholds, safe levels of exposure can be estimated. This brief review highlights how the fundamental principles governing hormonal effects - affinity, efficacy, potency, and mass action - dictate the existence of thresholds and why these principles also define the potential that exogenous chemicals might have to interfere with normal endocrine functioning.

Prehospital management of evolving critical illness by the primary care provider.

BACKGROUND: The factors that limit primary care providers (PCPs) from intervening for adults with evolving, acute, severe illness are less understood than the increasing frequency of management by acute care providers. METHODS: Rates of prehospital patient management by a PCP and of communication with acute care teams were measured in a multicenter, cross-sectional, descriptive study conducted in all four of the adult medical ICUs of the three hospitals in central Massachusetts that provide tertiary care. Rates were measured for 390 critical care encounters, using a validated instrument to abstract the medical record and conduct telephone interviews. RESULTS: PCPs implemented prehospital management for eight episodes of acute illness among 300 encounters. Infrequent prehospital management by PCPs was attributed to their lack of awareness of the patient's evolving acute illness. Only 21% of PCPs were aware of the acute illness before their patient was admitted to an ICU, and 33% were not aware that their patient was in an ICU. Rates of PCP involvement were not appreciably different among provider groups or by patient age, sex, insurance status, hospital, ICU, or ICU staffing model. CONCLUSIONS: We identified lack of PCP awareness of patients' acute illness and high rates of PCP referral to acute care providers as the most frequent barriers to prehospital management of evolving acute illness. These findings suggest that implementing processes that encourage early patient-PCP communication and increase rates of prehospital management of infections and acute exacerbations of chronic diseases could reduce use of acute care services.

Dedicated breast CT: geometric design considerations to maximize posterior breast coverage.

An Institutional Review Board-approved protocol was used to quantify breast tissue inclusion in 52 women, under conditions simulating both craniocaudal (CC) and mediolateral oblique (MLO) views in mammography, dedicated breast CT in the upright subject position, and dedicated breast CT in the prone subject position. Using skin as a surrogate for the underlying breast tissue, the posterior aspect of the breast that is aligned with the chest-wall edge of the breast support in a screen-film mammography system was marked with the study participants positioned for CC and MLO views. The union of skin marks with the study participants positioned for CC and MLO views was considered to represent chest-wall tissue available for imaging with mammography and served as the reference standard. For breast CT, a prone stereotactic breast biopsy unit and a custom-fabricated barrier were used to simulate conditions during prone and upright breast CT, respectively. For the same breast marked on the mammography system, skin marks were made along the breast periphery that was just anterior to the apertures of the prone biopsy unit and the upright barrier. The differences in skin marks between subject positioning simulating breast CT (prone, upright) and mammography were quantified at six anatomic locations. For each location, at least one study participant had a skin mark from breast CT (prone, upright) posterior to mammography. However for all study participants, there was at least one anatomic location where the skin mark from mammography was posterior to that from breast CT (prone, upright) positioning. The maximum amount by which the skin mark from mammography was posterior to breast CT (prone and upright) over all six locations was quantified for each study participant and pair-wise comparison did not exhibit statistically significant difference between prone and upright breast CT (paired t- test, p = 0.4). Quantitatively, for 95% of the study participants the skin mark from mammography was posterior to breast CT (prone or upright) by at the most 9 mm over all six locations. Based on the study observations, geometric design considerations targeting chest-wall coverage with breast CT equivalent to mammography, wherein part of the x-ray beam images through the swale during breast CT are provided. Assuming subjects can extend their chest in to a swale, the optimal swale-depth required to achieve equivalent coverage with breast CT images as mammograms for 95% of the subjects varies in the range of ~30-50 mm for clinical prototypes and was dependent on the system geometry.

A self-assessment survey of the Institutional Animal Care and Use Committee, part 2: structure and organizational functions.

Support for Institutional Animal Care and Use Committees (IACUCs) varies among those in animal use-related professions. The authors designed and carried out an anonymous survey to solicit opinions on the structure and organizational functions of IACUCs. They found that most respondents believed a single, institution-based IACUC was an appropriate venue for institutional approval of animal care and use, that their IACUCs represented their institutions' constituencies and that the unaffiliated IACUC members adequately represented their surrounding communities. Respondents believed that members came prepared for IACUC meetings, and a majority agreed that full committee reviews were more thorough than designated member reviews. The quality of veterinary care for animals was deemed to be very good. Participants reported that the status of the person submitting an animal use protocol, the perceived monetary value of a grant associated with a protocol and pressure for a rapid protocol review did not alter the quality of the protocol review. On many of the survey items, opinions of IACUC members differently significantly from those of non-members, and opinions of non-member IACUC administrators differed from those of IACUC chairpersons, perhaps owing to differences in responsibilities and perceived status.

A self-assessment survey of the Institutional Animal Care and Use Committee, Part 1: animal welfare and protocol compliance.

Nearly half of all external grants from the US National Institutes of Health require approval by the recipient organization's Institutional Animal Care and Use Committee (IACUC) before the funds can be used for research with animals. Given that large sums of money are spent annually on research involving animals, studies evaluating the strengths, weaknesses and overall effectiveness of IACUCs and similar animal welfare committees are needed. The authors designed and carried out a self-assessment survey on IACUC function and effectiveness. They found that 98% of all respondents believed that their IACUCs advanced animal welfare, but in many instances, veterinarians' responses to individual survey items were significantly different from those of other IACUC members. Protocol compliance, protocol review training and better understanding among non-committee members of the need for regulatory oversight are some areas where improvements could be made. Less than 50% of respondents stated that literature searches to find alternatives to animal use or painful or distressful procedures were helpful.

Synthesis and biological evaluation of adenosines with heterobicyclic and polycyclic N(6)-substituents as adenosine A(1) receptor agonists.

A concise synthesis of a series of N(6)-substituted adenosines with bicyclo[3.2.1]octan-6-yl and polycyclic N(6)-substituents has been developed. The adenosine A(1) receptor (A(1)R) affinity and potency of these compounds was initially assessed using competitive binding assays and cyclic adenosine monophosphate (cAMP) accumulation assays in DDT(1) MF-2 cells. The potency and receptor subtype selectivity of selected examples was further evaluated by measuring their effects on cAMP accumulation at all human adenosine receptor subtypes expressed in CHO cells. The results of these assays indicated that all of the synthesised N(6)-substituted adenosines are full agonists at A(1) R and activate this receptor selectively over the other adenosine receptor subtypes. The two standout compounds in terms of potency were N(6)-(3-thiabicyclo[3.2.1]octan-6-yl)adenosine and N(6)-(cubanylmethyl)adenosine with EC(50) values at human A(1)R of 2.3 nM and 1.1 nM, respectively. The cubanylmethyl derivative in particular proved to be highly receptor subtype selective. These two compounds were further evaluated in a simulated ischaemia model in cultured cardiomyoblasts, where they were found to impart protective effects under hypoxic conditions that resulted in a significant reduction in cell death.

Hyperspectral imaging for early detection of oxygenation and perfusion changes in irradiated skin.

Studies examining acute oxygenation and perfusion changes in irradiated skin are limited. Hyperspectral imaging (HSI), a method of wide-field, diffuse reflectance spectroscopy, provides noninvasive, quantified measurements of cutaneous oxygenation and perfusion. This study examines whether HSI can assess acute changes in oxygenation and perfusion following irradiation. Skin on both flanks of nude mice (n=20) was exposed to 50 Gy of beta radiation from a strontium-90 source. Hyperspectral images were obtained before irradiation and on selected days for three weeks. Skin reaction assessment was performed concurrently with HSI. Desquamative injury formed in all irradiated areas. Skin reactions were first seen on day 7, with peak formation on day 14, and resolution beginning by day 21. HSI demonstrated increased tissue oxygenation on day 1 before cutaneous changes were observed (p<0.001). Further increases over baseline were seen on day 14, but returned to baseline levels by day 21. For perfusion, similar increases were seen on days 1 and 14. Unlike tissue oxygenation, perfusion was decreased below baseline on day 21 (p<0.002). HSI allows for complete visualization and quantification of tissue oxygenation and perfusion changes in irradiated skin, and may also allow prediction of acute skin reactions based on early changes seen after irradiation.

Leukoaraiosis predicts poor 90-day outcome after acute large cerebral artery occlusion.

BACKGROUND: To date limited information regarding outcome-modifying factors in patients with acute intracranial large artery occlusion (ILAO) in the anterior circulation is available. Leukoaraiosis (LA) is a common finding among patients with ischemic stroke and has been associated with poor post-stroke outcomes but its association with ILAO remains poorly characterized. This study sought to clarify the contribution of baseline LA and other common risk factors to 90-day outcome (modified Rankin Scale, mRS) after stroke due to acute anterior circulation ILAO. METHODS: We retrospectively analyzed 1,153 consecutive patients with imaging-confirmed ischemic stroke during a 4-year period (2007-2010) at a single academic institution. The final study cohort included 87 patients with acute ILAO subjected to multimodal CT imaging within 24 h of symptom onset. LA severity was assessed using the van Swieten scale on non-contrast CT. Leptomeningeal collaterals were graded using CT angiogram source images. Hemorrhagic transformation (HT) was determined on follow-up CT. Multivariate logistic regression controlling for HT, treatment modality, demographic, as well as baseline clinical and imaging characteristics was used to identify independent predictors of a poor outcome (90-day mRS >2). RESULTS: The median National Institutes of Health Stroke Scale (NIHSS) at baseline was 15 (interquartile range 9-21). Twenty-four percent of the studied patients had severe LA. They were more likely to have hypertension (p = 0.028), coronary artery disease (p = 0.015), poor collaterals (p < 0.001), higher baseline NIHSS (p = 0.003), higher mRS at 90 days (p < 0.001), and were older (p = 0.002). Patients with severe LA had a uniformly poor outcome (p < 0.001) irrespective of treatment modality. Poor outcome was independently associated with higher baseline NIHSS (p < 0.001), worse LA (graded and dichotomized, p < 0.001), reduced leptomeningeal collaterals (graded and dichotomized, p < 0.001), presence of HT (p < 0.001), presence of parenchymal hemorrhages (p = 0.01), baseline mRS (p = 0.002), and older age (p = 0.043). The association between severe LA (p = 0.0056; OR 13.86; 95% CI 1.94-∞) and baseline NIHSS (p = 0.0001; OR 5.11; 95% CI 2.07-14.49 for each 10-point increase) with poor outcome maintained after adjustment for confounders in the final regression model. In this model, there was no significant association between presence of HT and poor outcome (p = 0.0572). CONCLUSION: Coexisting LA may predict poor functional outcome in patients with acute anterior circulation ILAO independent of other known important outcome predictors such as comorbid state, admission functional deficit, collateral status, hemorrhagic conversion, and treatment modality.

Disruption of IFT complex A causes cystic kidneys without mitotic spindle misorientation.

Intraflagellar transport (IFT) complexes A and B build and maintain primary cilia. In the mouse, kidney-specific or hypomorphic mutant alleles of IFT complex B genes cause polycystic kidneys, but the influence of IFT complex A proteins on renal development is not well understood. In the present study, we found that HoxB7-Cre-driven deletion of the complex A gene Ift140 from collecting ducts disrupted, but did not completely prevent, cilia assembly. Mutant kidneys developed collecting duct cysts by postnatal day 5, with rapid cystic expansion and renal dysfunction by day 15 and little remaining parenchymal tissue by day 20. In contrast to many models of polycystic kidney disease, precystic Ift140-deleted collecting ducts showed normal centrosomal positioning and no misorientation of the mitotic spindle axis, suggesting that disruption of oriented cell division is not a prerequisite to cyst formation in these kidneys. Precystic collecting ducts had an increased mitotic index, suggesting that cell proliferation may drive cyst expansion even with normal orientation of the mitotic spindle. In addition, we observed significant increases in expression of canonical Wnt pathway genes and mediators of Hedgehog and tissue fibrosis in highly cystic, but not precystic, kidneys. Taken together, these studies indicate that loss of Ift140 causes pronounced renal cystic disease and suggest that abnormalities in several different pathways may influence cyst progression.

Gender-specific reduction of estrogen-sensitive small RNA, miR-30b, in subjects with schizophrenia.

Estrogen signaling pathways affect cortical function and metabolism, are thought to play a role in the pathophysiology of schizophrenia, and exert neuroprotective effects in female subjects at risk. However, the molecular signatures of estrogen signaling in normal and diseased cerebral cortex remain largely unexplored. Expression of the estrogen-sensitive small RNA, microRNA-30b (miR-30b), was studied in 30 controls and 30 matched samples from subjects diagnosed with schizophrenia from prefrontal cortex (PFC), as well as in 23 samples from parietal cortex (12 controls and 11 schizophrenia cases). The majority of case and control samples were genotyped for an estrogen receptor α (Esr1) sequence variant (rs2234693) previously associated with genetic risk, and a subset of them were subjected to further analysis to determine expression of mature and precursor forms of miR-30b (pre/pri-miR-30b). Gender-dimorphic expression was also explored in mouse frontal cortex and hippocampus. A significant interaction between gender and diagnosis was discovered for changes in mature miR-30b levels, so that miR-30b expression was significantly reduced in the cerebral cortex of female but not male subjects with schizophrenia. In addition, disease-related changes in miR-30b expression in a subset of female subjects were further modulated by Esr1 genotype. Changes after antipsychotic drug exposure remained insignificant. These preliminary findings point to the possibility that disease-related changes in the expression of small noncoding RNAs such as miR-30b in schizophrenia could be influenced by gender and potentially regulated by estrogen signaling.

Determination of cystic duct patency using hepatobiliary MRI with gadoxetate disodium: is T1 precontrast imaging necessary?

PURPOSE: To determine the need for precontrast T1-weighted imaging in determining cystic duct patency using hepatobiliary phase imaging with gadoxetate disodium-enhanced magnetic resonance imaging (MRI). MATERIALS AND METHODS: MRI exams using gadoxetate disodium from October 4, 2008 to April 14, 2010 were reviewed in a retrospective fashion. Two reviewers independently reviewed only the 20-minute T1-weighted delayed postcontrast images to determine the presence of excreted contrast in the gallbladder lumen. Contrast was deemed present if hyperintense signal material was seen in the antidependent portion of the gallbladder lumen. The actual presence of contrast in the gallbladder was determined by directly comparing the pre- and postcontrast T1-weighted images using consensus review. RESULTS: In all, 187 cases were included. Three (1.6%) were deemed indeterminate due to complete homogeneous opacification of the gallbladder. All three cases were identified as indeterminate by both reviewers. Of the remaining 184 cases, 136 filled (74%) and 48 did not fill (26%). Both reviewers correctly identified 136/136 cases of gallbladder filling. Reviewer A identified 47/48 cases of nonfilling and reviewer B identified 46/48 cases of nonfilling. Sensitivity and specificity were 100% and 98% for reviewer A and 100% and 96% for reviewer B, respectively. CONCLUSION: The presence of excreted contrast in the gallbladder lumen can be determined using gadoxetate disodium-enhanced MRI without precontrast T1-weighted imaging.