Percutaneous Cholecystostomy: Procedural Guidance and Future Directions for Clinical Management.

Percutaneous cholecystostomy (PC) is a recognized treatment option for the management of acute cholecystitis and is an integral component of the treatment algorithm in the 2018 Tokyo Guidelines. The utilization of PC has significantly increased over the past 30 years, particularly in the setting of critically ill patients and those with extensive comorbidities who are poor surgical candidates. The indications, complications, patient selection considerations, and technical complexities of the procedure will be discussed.

RNA polymerases reshape chromatin architecture and couple transcription on individual fibers.

RNA polymerases must initiate and pause within a complex chromatin environment, surrounded by nucleosomes and other transcriptional machinery. This environment creates a spatial arrangement along individual chromatin fibers ripe for both competition and coordination, yet these relationships remain largely unknown owing to the inherent limitations of traditional structural and sequencing methodologies. To address this, we employed long-read chromatin fiber sequencing (Fiber-seq) in Drosophila to visualize RNA polymerase (Pol) within its native chromatin context with single-molecule precision along up to 30 kb fibers.

Single-nucleoid architecture reveals heterogeneous packaging of mitochondrial DNA.

Cellular metabolism relies on the regulation and maintenance of mitochondrial DNA (mtDNA). Hundreds to thousands of copies of mtDNA exist in each cell, yet because mitochondria lack histones or other machinery important for nuclear genome compaction, it remains unresolved how mtDNA is packaged into individual nucleoids. In this study, we used long-read single-molecule accessibility mapping to measure the compaction of individual full-length mtDNA molecules at near single-nucleotide resolution.

RNA polymerases reshape chromatin and coordinate transcription on individual fibers.

During eukaryotic transcription, RNA polymerases must initiate and pause within a crowded, complex environment, surrounded by nucleosomes and other transcriptional activity. This environment creates a spatial arrangement along individual chromatin fibers ripe for both competition and coordination, yet these relationships remain largely unknown owing to the inherent limitations of traditional structural and sequencing methodologies. To address these limitations, we employed long-read chromatin fiber sequencing (Fiber-seq) to visualize RNA polymerases within their native chromatin context at single-molecule and near single-nucleotide resolution along up to 30 kb fibers.

Comparing outcomes of percutaneous cholecystostomy drain placement between patients within and outside of Tokyo guidelines diagnostic criteria for acute cholecystitis.

Objective: To compare outcomes following percutaneous cholecystostomy drain placement based on presence or absence of Tokyo Guidelines diagnostic criteria for acute cholecystitis.

Methods: Chart review was performed to identify the presence or absence of Tokyo Guidelines diagnostic criteria for acute cholecystitis in 146 patients who underwent percutaneous cholecystostomy between 2012 and 2015. Those who met criteria were compared to those who did not in terms of demographics, laboratory values, drain indwelling time, treatment response, eventual surgical management, and 30-day mortality.

Percutaneous treatment of IVC obstruction due to post-resection hepatic torsion associated with IVC thrombosis.

Background: Migration of the left hepatic lobe into the potential space following right lobe resection can result in torsion and hepatic venous outflow obstruction with compromised venous return from the IVC. If untreated, significant morbidity and mortality can develop.

Case Presentation: We report a case of a 29-year-old female with Lynch syndrome who underwent right lobe resection for a metastatic hepatic tumor.

A Single-Institutional Comparative Analysis of Advanced Versus Standard Snare Removal of Inferior Vena Cava Filters.

Purpose: To investigate differences in procedure time, radiation exposure, and periprocedural complications associated with advanced inferior vena cava (IVC) filter retrieval compared with standard snare retrieval.

Materials And Methods: A total of 378 patients underwent standard or advanced IVC filter retrieval over a 5-year period. Technical success, retrieval techniques, fluoroscopy time, radiation dose, and complications were analyzed.

Update on Preoperative Embolization of Bone Metastases.

Management of patients with bone metastasis is complex and should include different specialties. Goals of therapy should be identified for each individual patient prior to the start of treatment. Preoperative embolization has generally been considered a safe and effective means of reducing intraoperative blood loss with recent studies and advances in technique reported.

Gender-Specific Factors Influencing Medical Students' Career Choice of IR.

The authors conducted an anonymous survey to assess positive and negative factors that may affect medical students' decisions to pursue a career in interventional radiology (IR). The survey was sent to registrants for the Midwest IR Student Symposium in 2016 and/or 2017, with a response rate of 13%; male and female responses were then compared. Female and male medical students shared similar rankings of factors affecting their decisions about choosing IR as a career, such as concern about lifestyle and excitement about therapeutic applications.

Experimental maps of DNA structure at nucleotide resolution distinguish intrinsic from protein-induced DNA deformations.

Recognition of DNA by proteins depends on DNA sequence and structure. Often unanswered is whether the structure of naked DNA persists in a protein-DNA complex, or whether protein binding changes DNA shape. While X-ray structures of protein-DNA complexes are numerous, the structure of naked cognate DNA is seldom available experimentally.

Complications and Retrieval Data of Vena Cava Filters Based on Specific Infrarenal Location.

Purpose: Although recommended placement of IVC filters is with their tips positioned at the level of the renal vein inflow, in practice, adherence is limited due to clinical situation or IVC anatomy. We seek to evaluate the indwelling and retrieval complications of IVC filters based on their specific position within the infrarenal IVC.

Materials And Methods: Retrospective, single institution study of 333 consecutive infrarenal vena cava filters placed by interventional radiologists in patients with an average age of 62.

A microRNA program in the C. elegans hypodermis couples to intestinal mTORC2/PQM-1 signaling to modulate fat transport.

Animals integrate metabolic, developmental, and environmental information before committing key resources to reproduction. In Caenorhabditis elegans, adult animals transport fat from intestinal cells to the germline to promote reproduction. We identified a microRNA (miRNA)-regulated developmental timing pathway that functions in the hypodermis to nonautonomously coordinate the mobilization of intestinal fat stores to the germline upon initiation of adulthood.

Indwelling and Retrieval Complications of Denali and Celect Infrarenal Vena Cava Filters.

Purpose: To compare indwelling and retrieval complications of Denali and Celect filters placed in the infrarenal inferior vena cava (IVC).

Materials And Methods: A retrospective study was conducted over 2 years at a single institution in which 171 Denali and 162 Celect filters were placed in 333 patients with a mean age of 62.3 years ± 15.

GBshape: a genome browser database for DNA shape annotations.

Many regulatory mechanisms require a high degree of specificity in protein-DNA binding. Nucleotide sequence does not provide an answer to the question of why a protein binds only to a small subset of the many putative binding sites in the genome that share the same core motif. Whereas higher-order effects, such as chromatin accessibility, cooperativity and cofactors, have been described, DNA shape recently gained attention as another feature that fine-tunes the DNA binding specificities of some transcription factor families.

Chemical probing of RNA with the hydroxyl radical at single-atom resolution.

While hydroxyl radical cleavage is widely used to map RNA tertiary structure, lack of mechanistic understanding of strand break formation limits the degree of structural insight that can be obtained from this experiment. Here, we determine how individual ribose hydrogens of sarcin/ricin loop RNA participate in strand cleavage. We find that substituting deuterium for hydrogen at a ribose 5'-carbon produces a kinetic isotope effect on cleavage; the major cleavage product is an RNA strand terminated by a 5'-aldehyde.

Comparative analysis of metazoan chromatin organization.

Genome function is dynamically regulated in part by chromatin, which consists of the histones, non-histone proteins and RNA molecules that package DNA. Studies in Caenorhabditis elegans and Drosophila melanogaster have contributed substantially to our understanding of molecular mechanisms of genome function in humans, and have revealed conservation of chromatin components and mechanisms. Nevertheless, the three organisms have markedly different genome sizes, chromosome architecture and gene organization.

Use of three-dimensional power Doppler sonography in the diagnosis of uterine arteriovenous malformation and follow-up after uterine artery embolization: Case report and brief review of literature.

Arteriovenous malformations (AVM) of the uterus can cause life-threatening hemorrhage. Unexplained, heavy vaginal bleeding in a reproductive age woman should raise suspicion for an AVM. Here a 37-year-old woman had increasingly severe vaginal bleeding for 15 days.

A unique variant of Poland-Mobius syndrome with dextrocardia and a 3q23 gain.

The combined Poland and Mobius syndrome occurs rarely and with a wide range of features. There is no consensus on the etiology of this syndrome; familial, sporadic cases and likely environmental insult cases have been reported. This sporadic case represents a unique variant in the spectrum of this syndrome.

A map of minor groove shape and electrostatic potential from hydroxyl radical cleavage patterns of DNA.

DNA shape variation and the associated variation in minor groove electrostatic potential are widely exploited by proteins for DNA recognition. Here we show that the hydroxyl radical cleavage pattern is a quantitative measure of DNA backbone solvent accessibility, minor groove width, and minor groove electrostatic potential, at single nucleotide resolution. We introduce maps of DNA shape and electrostatic potential as tools for understanding how proteins recognize binding sites in a genome.

A computational method to search for DNA structural motifs in functional genomic elements.

The rapidly increasing availability of DNA sequence data from modern high-throughput experimental techniques has created the need for computational algorithms to aid in motif discovery in genomic DNA. Such algorithms are typically used to find a statistical representation of the nucleotide sequence of the target site of a DNA-binding protein within a collection of DNA sequences that are thought to contain segments to which the protein is bound. A major assumption of these algorithms is that the protein recognizes the primary order of nucleotides in the sequence.

DNA shape, genetic codes, and evolution.

Although the three-letter genetic code that maps nucleotide sequence to protein sequence is well known, there must exist other codes that are embedded in the human genome. Recent work points to sequence-dependent variation in DNA shape as one mechanism by which regulatory and other information could be encoded in DNA. Recent advances include the discovery of shape-dependent recognition of DNA that depends on minor groove width and electrostatics, the existence of overlapping codes in protein-coding regions of the genome, and evolutionary selection for compensatory changes in nucleotide composition that facilitate nucleosome occupancy.

Local DNA topography correlates with functional noncoding regions of the human genome.

The three-dimensional molecular structure of DNA, specifically the shape of the backbone and grooves of genomic DNA, can be dramatically affected by nucleotide changes, which can cause differences in protein-binding affinity and phenotype. We developed an algorithm to measure constraint on the basis of similarity of DNA topography among multiple species, using hydroxyl radical cleavage patterns to interrogate the solvent-accessible surface area of DNA. This algorithm found that 12% of bases in the human genome are evolutionarily constrained-double the number detected by nucleotide sequence-based algorithms.

Footprinting protein-DNA complexes using the hydroxyl radical.

Hydroxyl radical footprinting has been widely used for studying the structure of DNA and DNA-protein complexes. The high reactivity and lack of base specificity of the hydroxyl radical makes it an excellent probe for high-resolution footprinting of DNA-protein complexes; this technique can provide structural detail that is not achievable using DNase I footprinting. Hydroxyl radical footprinting experiments can be carried out using readily available and inexpensive reagents and lab equipment.