Impact of Implementing Contrast-Enhanced Ultrasound for Antegrade Nephrostogram After Percutaneous Nephrolithotomy.

OBJECTIVES: To report results from a quality improvement (QI) project evaluating diagnostic performance, hospital resource use, and patient response data for postoperative contrast-enhanced ultrasound (CEUS) antegrade nephrostogram after percutaneous nephrolithotomy. METHODS: For this Health Insurance Portability and Accountability Act-compliant, Institutional Review Board-approved study, QI data were deidentified and analyzed. On the first postoperative day after percutaneous nephrolithotomy, patients underwent both CEUS and fluoroscopic antegrade nephrostogram. For CEUS, 1.0 mL of Lumason (sulfur hexafluoride lipid type A microspheres; Bracco Diagnostics, Inc, Monroe Township, NJ) was injected via an indwelling nephrostomy tube, with ureteral patency confirmed by identifying intravesical ultrasound (US) contrast. Diagnostic performance for ureteral patency and contrast extravasation was calculated (with fluoroscopy as the reference standard). The examination time, room time, physician time, hospital costs, and patient response data were compared. The mean, standard deviation, 95% confidence interval, differences in mean, and 95% confidence interval of differences were calculated. RESULTS: Eighty-one examinations were performed in 73 patients during the QI period. The sensitivity and specificity of CEUS for ureteral patency were 96% and 57%, respectively. There was no significant difference in time metrics between modalities, and the cost analysis showed lower direct and indirect costs for CEUS. Patient responses revealed lower levels of comfort for CEUS relative to fluoroscopy, without significant differences in reported pain or effort levels. CONCLUSIONS: Contrast-enhanced US showed very high sensitivity for ureteral patency; the relatively low specificity may have resulted from false-negative results in fluoroscopy. The hospital costs and resource use of CEUS compared favorably to fluoroscopy. Contrast-enhanced US also offers inherent advantages, including portability and lack of ionizing radiation.

Ultrafast Dynamics at Lipid-Water Interfaces.

Lipid membranes are more than just barriers between cell compartments; they provide molecular environments with a finely tuned balance between hydrophilic and hydrophobic interactions that enable proteins to dynamically fold and self-assemble to regulate biological function. Characterizing dynamics at the lipid-water interface is essential to understanding molecular complexities from the thermodynamics of liquid-liquid phase separation down to picosecond-scale reorganization of interfacial hydrogen-bond networks.Ultrafast vibrational spectroscopy, including two-dimensional infrared (2D IR) and vibrational sum-frequency generation (VSFG) spectroscopies, is a powerful tool to examine picosecond interfacial dynamics. Two-dimensional IR spectroscopy provides a bond-centered view of dynamics with subpicosecond time resolutions, as vibrational frequencies are highly sensitive to the local environment. Recently, 2D IR spectroscopy has been applied to carbonyl and phosphate vibrations intrinsically located at the lipid-water interface. Interface-specific VSFG spectroscopy probes the water vibrational modes directly, accessing H-bond strength and water organization at lipid headgroup positions. Signals in VSFG arise from the interfacial dipole contributions, directly probing headgroup ordering and water orientation to provide a structural view of the interface.In this Account we discuss novel applications of ultrafast spectroscopy to lipid membranes, a field that has experienced significant growth over the past decade. In particular, ultrafast experiments now offer a molecular perspective on increasingly complex membranes. The powerful combination of ultrafast, interface-selective spectroscopy and simulations opens up new routes to understanding multicomponent membranes and their function. This Account highlights key prevailing views that have emerged from recent experiments: (1) Water dynamics at the lipid-water interface are slow compared to those of bulk water as a result of disrupted H-bond networks near the headgroups. (2) Peptides, ions, osmolytes, and cosolvents perturb interfacial dynamics, indicating that dynamics at the interface are affected by bulk solvent dynamics and vice versa. (3) The interfacial environment is generally dictated by the headgroup structure and orientation, but hydrophobic interactions within the acyl chains also modulate interfacial dynamics. Ultrafast spectroscopy has been essential to characterizing the biophysical chemistry of the lipid-water interface; however, challenges remain in interpreting congested spectra as well as designing appropriate model systems to capture the complexity of a membrane environment.

Ultrafast Spectroscopy of Lipid-Water Interfaces: Transmembrane Crowding Drives H-Bond Dynamics.

Biology takes place in crowded, heterogeneous environments, and it is therefore essential to account for crowding effects in our understanding of biophysical processes at the molecular level. Comparable to the cytosol, proteins occupy approximately 30% of the plasma membrane surface; thus, crowding should have an effect on the local structure and dynamics at the lipid-water interface. Using a combination of ultrafast two-dimensional infrared spectroscopy and molecular dynamics simulations, we quantify the effects of membrane peptide concentration on the picosecond interfacial H-bond dynamics. The measurements reveal a nonmonotonic dependence of water orientation and dynamics as a function of transmembrane peptide:lipid ratio. We observe three dynamical regimes: a "pure lipid-like" regime at low peptide concentrations, a bulk-like region at intermediate peptide concentrations where dynamics are faster by ∼20% compared to those of the pure lipid bilayer, and a crowded regime where high peptide concentrations slow dynamics by ∼50%.

Liquid-Liquid Phase Separation Produces Fast H-Bond Dynamics in DMSO-Water Mixtures.

Liquid-liquid phase separation is common in complex mixtures, but the behavior of nanoconfined liquids is poorly understood from a physical perspective. Dimethyl sulfoxide (DMSO) is an amphiphilic molecule with unique concentration-dependent bulk properties in mixtures with water. Here, we use ultrafast two-dimensional infrared (2D IR) spectroscopy to measure the H-bond dynamics of two probe molecules with different polarities: formamide (FA) and dimethylformamide (DMF). Picosecond H-bond dynamics are fastest in the intermediate concentration regime (20-50 mol % DMSO), because such confined water exhibits bulk-like dynamics. Each vibrational probe experiences a unique microscopic environment as a result of nanoscale phase separation. Molecular dynamics simulations show that the dynamics span multiple time scales, from femtoseconds to nanoseconds. Our studies suggest a previously unknown liquid environment, which we label "local bulk", in which despite the local heterogeneity, the ultrafast H-bond dynamics are similar to bulk water.

Ultrafast pH-jump two-dimensional infrared spectroscopy.

We present a pH-jump two-dimensional infrared (2D IR) spectrometer to probe pH-dependent conformational changes from nanoseconds to milliseconds. The design incorporates a nanosecond 355 nm source into a pulse-shaper-based 2D IR spectrometer to trigger dissociation of a caged proton prior to probing subsequent conformational changes with femtosecond 2D IR spectroscopy. We observe a blue shift in the amide I mode (C═O stretch) of diglycine induced by protonation of the terminal amine. This method combines the bond-specific structural sensitivity of ultrafast 2D IR with triggered conformational dynamics, providing structural access to multiscale biomolecular transformations such as protein folding.

Imaging and the Lung Transplant Patient.

Lung transplantation can prolong and improve quality of life for patients affected by end-stage lung disease. Potential lung transplant patients undergo a rigorous preoperative assessment that includes multiple medical imaging studies. These studies provide information that help physicians determine whether the patient is a surgical candidate, as well as the surgical technique that should be used during transplantation. Imaging studies also are used in long-term care to detect complications in patients after lung transplantation.

Synthetic Essentiality of Metabolic Regulator PDHK1 in PTEN-Deficient Cells and Cancers.

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a tumor suppressor and bi-functional lipid and protein phosphatase. We report that the metabolic regulator pyruvate dehydrogenase kinase1 (PDHK1) is a synthetic-essential gene in PTEN-deficient cancer and normal cells. The PTEN protein phosphatase dephosphorylates nuclear factor κB (NF-κB)-activating protein (NKAP) and limits NFκB activation to suppress expression of PDHK1, a NF-κB target gene. Loss of the PTEN protein phosphatase upregulates PDHK1 to induce aerobic glycolysis and PDHK1 cellular dependence. PTEN-deficient human tumors harbor increased PDHK1, a biomarker of decreased patient survival. This study uncovers a PTEN-regulated signaling pathway and reveals PDHK1 as a potential target in PTEN-deficient cancers.

Site-Specific Peptide Probes Detect Buried Water in a Lipid Membrane.

Transmembrane peptides contain polar residues in the interior of the membrane, which may alter the electrostatic environment and favor hydration in the otherwise nonpolar environment of the membrane core. Here, we demonstrate a general, nonperturbative strategy to probe hydration of the peptide backbone at specific depths within the bilayer using a combination of site-specific isotope labels, ultrafast two-dimensional infrared spectroscopy, and spectral modeling based on molecular dynamics simulations. Our results show that the amphiphilic pH-low insertion peptide supports a highly heterogeneous environment, with significant backbone hydration of nonpolar residues neighboring charged residues. For example, a leucine residue located as far as 1 nm into the hydrophobic bulk reports hydrogen-bonded populations as high as ∼20%. These findings indicate that the polar nature of these residues may facilitate the transport of water molecules into the hydrophobic core of the membrane.

Microbial Community Succession and Nutrient Cycling Responses following Perturbations of Experimental Saltwater Aquaria.

Although aquaria are common features of homes and other buildings, little is known about how environmental perturbations (i.e., tank cleaning, water changes, addition of habitat features) impact the diversity and succession of aquarium microbial communities. In this study, we sought to evaluate the hypotheses that newly established aquaria show clear microbial successional patterns over time and that common marine aquarium-conditioning practices, such as the addition of ocean-derived "live rocks" (defined as any "dead coral skeleton covered with crustose coralline algae" transferred into an aquarium from open ocean habitats) impact the diversity of microbial populations as well as nitrogen cycling in aquaria. We collected water chemistry data alongside water and sediment samples from two independent and newly established saltwater aquaria over a 3-month period. Microbial communities in samples were assessed by DNA extraction, amplification of the 16S rRNA gene, and Illumina MiSeq sequencing. Our results showed clear and replicable patterns of community succession in both aquaria, with the existence of multiple stable states for aquarium microbial assemblages. Notably, our results show that changes in aquarium microbial communities do not always correlate with water chemistry measurements and that operational taxonomic unit (OTU)-level patterns relevant to nitrogen cycling were not reported as statistically significant. Overall, our results demonstrate that aquarium perturbations have a substantial impact on microbial community profiles of aquarium water and sediment and that the addition of live rocks improves nutrient cycling by shifting aquarium communities toward a more typical saltwater assemblage of microbial taxa.IMPORTANCE Saltwater aquaria are living systems that support a complex biological community of fish, invertebrates, and microbes. The health and maintenance of saltwater tanks are pressing concerns for home hobbyists, zoos, and professionals in the aquarium trade; however, we do not yet understand the underlying microbial species interactions and community dynamics which contribute to tank setup and conditioning. This report provides a detailed view of ecological succession and changes in microbial community assemblages in two saltwater aquaria which were sampled over a 3-month period, from initial tank setup and conditioning with "live rocks" through subsequent tank cleanings and water replacement. Our results showed that microbial succession appeared to be consistent and replicable across both aquaria. However, changes in microbial communities did not always correlate with water chemistry measurements, and aquarium microbial communities appear to have shifted among multiple stable states without any obvious buildup of undesirable nitrogen compounds in the tank environment.

Fluoroscopic Evaluation of Adult Male Urethral Abnormalities.

Retrograde urethrograms and voiding cystourethrograms provide clinicians with important information to determine treatment options and surgical interventions for patients with urethral abnormalities. This article discusses the elements with which radiologic technologists should be familiar, including urethra anatomy, the pathology of urethral abnormalities, imaging techniques, and special considerations for preoperative and postoperative patients.

Inactivation of Capicua drives cancer metastasis.

Metastasis is the leading cause of death in people with lung cancer, yet the molecular effectors underlying tumor dissemination remain poorly defined. Through the development of an in vivo spontaneous lung cancer metastasis model, we show that the developmentally regulated transcriptional repressor Capicua (CIC) suppresses invasion and metastasis. Inactivation of CIC relieves repression of its effector ETV4, driving ETV4-mediated upregulation of MMP24, which is necessary and sufficient for metastasis. Loss of CIC, or an increase in levels of its effectors ETV4 and MMP24, is a biomarker of tumor progression and worse outcomes in people with lung and/or gastric cancer. Our findings reveal CIC as a conserved metastasis suppressor, highlighting new anti-metastatic strategies that could potentially improve patient outcomes.

Combined chemical-genetic approach identifies cytosolic HSP70 dependence in rhabdomyosarcoma.

Cytosolic and organelle-based heat-shock protein (HSP) chaperones ensure proper folding and function of nascent and injured polypeptides to support cell growth. Under conditions of cellular stress, including oncogenic transformation, proteostasis components maintain homeostasis and prevent apoptosis. Although this cancer-relevant function has provided a rationale for therapeutically targeting proteostasis regulators (e.g., HSP90), cancer-subtype dependencies upon particular proteostasis components are relatively undefined. Here, we show that human rhabdomyosarcoma (RMS) cells, but not several other cancer cell types, depend upon heat-shock protein 70 kDA (HSP70) for survival. HSP70-targeted therapy (but not chemotherapeutic agents) promoted apoptosis in RMS cells by triggering an unfolded protein response (UPR) that induced PRKR-like endoplasmic reticulum kinase (PERK)-eukaryotic translation initiation factor α (eIF2α)-CEBP homologous protein (CHOP) signaling and CHOP-mediated cell death. Intriguingly, inhibition of only cytosolic HSP70 induced the UPR, suggesting that the essential activity of HSP70 in RMS cells lies at the endoplasmic reticulum-cytosol interface. We also found that increased CHOP mRNA in clinical specimens was a biomarker for poor outcomes in chemotherapy-treated RMS patients. The data suggest that, like human epidermal growth factor receptor 2 (HER2) amplification in breast cancer, increased CHOP in RMS is a biomarker of decreased response to chemotherapy but enhanced response to targeted therapy. Our findings identify the cytosolic HSP70-UPR axis as an unexpected regulator of RMS pathogenesis, revealing HSP70-targeted therapy as a promising strategy to engage CHOP-mediated apoptosis and improve RMS treatment. Our study highlights the utility of dissecting cancer subtype-specific dependencies on proteostasis networks to uncover unanticipated cancer vulnerabilities.

An Empirical IR Frequency Map for Ester C═O Stretching Vibrations.

We present an approach for parametrizing spectroscopic maps of carbonyl groups against experimental IR absorption spectra. The model correlates electric fields sampled from molecular dynamics simulations with vibrational frequencies and line shapes in different solvents. We perform an exhaustive search of parameter combinations and optimize the parameter values for the ester carbonyl stretching mode in ethyl acetate by comparing to experimental FTIR spectra of the small molecule in eight different solvents of varying polarities. Hydrogen-bonding solvents require that the peaks are fit independently for each hydrogen bond ensemble to compensate for improper sampling in molecular dynamics simulations. Spectra simulated using the optimized electrostatic map reproduce C═O IR absorption spectra of ethyl acetate with a line center RMSD error of 4.9 cm(-1) over 12 different solvents whose measured line centers span a 45 cm(-1) range. In combination with molecular dynamics simulations, this spectroscopic map will be useful in interpreting spectra of ester groups in heterogeneous environments such as lipid membranes.

Esophagectomy and Gastric Pull-through Procedures: Surgical Techniques, Imaging Features, and Potential Complications.

Esophagectomy takes the center stage in the curative treatment of local and local-regional esophageal cancer. It is a complex procedure with a high postoperative complication rate. When interpreting imaging studies, radiologists must understand the surgical techniques used and their potential complications. The most common surgical techniques are transthoracic esophagectomies, such as the Ivor Lewis and McKeown techniques, and transhiatal esophagectomy. Variations of these techniques include different choices of conduit (ie, stomach, colon, or jejunum) to serve in lieu of the resected esophagus. Postoperative imaging and accurate interpretation is vital in the aftercare of these patients. Chest radiographs, esophagrams, and computed tomographic images play an essential role in early identification of complications. Pulmonary complications and anastomotic leaks are the leading causes of postoperative morbidity and mortality secondary to esophagectomy. Other complications include technical and functional problems and delayed complications such as anastomotic strictures and disease recurrence. An esophagographic technique is described that is performed by using hand injection of contrast material into an indwelling nasogastric tube. Familiarity with the various types of esophagectomy and an understanding of possible complications are of utmost importance for radiologists and allow them to be key participants in the treatment of patients undergoing these complicated procedures.

Radiology Physician Extenders: A Literature Review of the History and Current Roles of Physician Extenders in Medical Imaging.

UNLABELLED: The purpose of the literature review was to assess the origins of radiology physician extenders and examine the current roles found in the literature of advanced practice physician extenders within medical imaging. METHODS: Twenty-six articles relating to physician assistants (PAs), nurse practitioners (NPs), radiologist assistants (RAs), and nuclear medicine advanced associates (NMAAs) were reviewed to discern similarities and differences in history, scope of practice, and roles in the medical imaging field. RESULTS: The literature showed PAs and NPs are working mostly in interventional radiology. PAs, NPs, and RAs perform similar tasks in radiology, including history and physicals, evaluation and management, preprocedure work-up, obtaining informed consent, initial observations/reports, and post-procedure follow-up. NPs and PAs perform a variety of procedures but most commonly vascular access, paracentesis, and thoracentesis. RAs perform gastrointestinal, genitourinary, nonvascular invasive fluoroscopy procedures, and vascular access procedures. The review revealed NMAAs are working in an advanced role, but no specific performances of procedures was found in the literature, only suggested tasks and clinical competencies. CONCLUSION: PAs, NPs, and RAs are currently the three main midlevel providers used in medical imaging. These midlevel providers are being used in a variety of ways to increase the efficiency of the radiologist and provide diagnostic and therapeutic radiologic procedures to patients. NMAAs are being used in medical imaging but little literature is available on current roles in clinical practice. More research is needed to assess the exact procedures and duties being performed by these medical imaging physician extenders.

Porphyrobacter mercurialis sp. nov., isolated from a stadium seat and emended description of the genus Porphyrobacter.

A novel, Gram-negative, non-spore-forming, pleomorphic yellow-orange bacterial strain was isolated from a stadium seat. Strain Coronado(T) falls within the Erythrobacteraceae family and the genus Porphyrobacter based on 16S rRNA phylogenetic analysis. This strain has Q-10 as the predominant respiratory lipoquinone, as do other members of the family. The fatty acid profile of this strain is similar to other Porphyrobacter, however Coronado(T) contains predominately C18:1ω7cis and C16:0, a high percentage of the latter not being observed in any other Erythrobacteraceae. This strain is catalase-positive and oxidase-negative, can grow from 4 to 28 °C, at NaCl concentrations 0.1-1.5%, and at pH 6.0-8.0. On the basis of phenotypic and phylogenetic data presented in this study, strain Coronado(T) represents a novel species in the Porphyrobacter genus for which the name Porphyrobacter mercurialis sp. nov. is proposed; the type strain is Coronado(T) (=DSMZ 29971, =LMG 28700).

3-D Isotropic MR Imaging for Planning Bone Reconstruction in Patients With Femoroacetabular Impingement.

BACKGROUND: Femoroacetabular impingement (FAI) is commonly seen in young or middle-aged patients. Early detection and correction of FAI-related bony deformities or pelvic realignment are essential to prevent the development or progression of hip osteoarthritis. DISCUSSION: Computed tomography (CT) and magnetic resonance (MR) imaging are the reference standards for the evaluation of bony anatomy and treatable internal derangement findings of the hip, respectively. Surgeons prefer CT imaging for preoperative bone delineation because of its 3-D isotropic capabilities and excellent multiplanar reconstructions. Three-Tesla (3T) MR scans enable high-resolution 3-D MR reconstructions for bone depiction similar to 3-D CT reconstructions and have the potential to eliminate the need for duplicate (CT and MR) scanning. CONCLUSION: This technical report illustrates the feasibility of such an approach and compares bone rendering obtained using isotropic data from 3-D MR with 3-D CT in the same patient.

RAS-MAPK dependence underlies a rational polytherapy strategy in EML4-ALK-positive lung cancer.

One strategy for combating cancer-drug resistance is to deploy rational polytherapy up front that suppresses the survival and emergence of resistant tumor cells. Here we demonstrate in models of lung adenocarcinoma harboring the oncogenic fusion of ALK and EML4 that the GTPase RAS-mitogen-activated protein kinase (MAPK) pathway, but not other known ALK effectors, is required for tumor-cell survival. EML4-ALK activated RAS-MAPK signaling by engaging all three major RAS isoforms through the HELP domain of EML4. Reactivation of the MAPK pathway via either a gain in the number of copies of the gene encoding wild-type K-RAS (KRAS(WT)) or decreased expression of the MAPK phosphatase DUSP6 promoted resistance to ALK inhibitors in vitro, and each was associated with resistance to ALK inhibitors in individuals with EML4-ALK-positive lung adenocarcinoma. Upfront inhibition of both ALK and the kinase MEK enhanced both the magnitude and duration of the initial response in preclinical models of EML4-ALK lung adenocarcinoma. Our findings identify RAS-MAPK dependence as a hallmark of EML4-ALK lung adenocarcinoma and provide a rationale for the upfront inhibition of both ALK and MEK to forestall resistance and improve patient outcomes.

Draft Genome Sequence of Curtobacterium flaccumfaciens Strain UCD-AKU (Phylum Actinobacteria).

Here we present the draft genome of an actinobacterium, Curtobacterium flaccumfaciens strain UCD-AKU, isolated from a residential carpet. The genome assembly contains 3,692,614 bp in 130 contigs. This is the first member of the Curtobacterium genus to be sequenced.