Risk of severe COVID-19 infection among adults with prior exposure to children.

Susceptibility and severity of COVID-19 infection vary widely. Prior exposure to endemic coronaviruses, common in young children, may protect against SARS-CoV-2. We evaluated risk of severe COVID-19 among adults with and without exposure to young children in a large, integrated healthcare system. Adults with children 0-5 years were matched 1:1 to adults with children 6-11 years, 12-18 years, and those without children based upon a COVID-19 propensity score and risk factors for severe COVID-19. COVID-19 infections, hospitalizations, and need for intensive care unit (ICU) were assessed in 3,126,427 adults, of whom 24% (N = 743,814) had children 18 years or younger, and 8.8% (N = 274,316) had a youngest child 0-5 years. After 1:1 matching, propensity for COVID-19 infection and risk factors for severe COVID-19 were well balanced between groups. Rates of COVID-19 infection were slightly higher for adults with exposure to older children (incident risk ratio, 1.09, 95% confidence interval, [1.05-1.12] and IRR 1.09 [1.05-1.13] for adults with children 6-11 and 12-18, respectively), compared to those with children 0-5 years, although no difference in rates of COVID-19 illness requiring hospitalization or ICU admission was observed. However, adults without exposure to children had lower rates of COVID-19 infection (IRR 0.85, [0.83-0.87]) but significantly higher rates of COVID-19 hospitalization (IRR 1.49, [1.29-1.73]) and hospitalization requiring ICU admission (IRR 1.76, [1.19-2.58]) compared to those with children aged 0-5. In a large, real-world population, exposure to young children was associated with less severe COVID-19 illness. Endemic coronavirus cross-immunity may play a role in protection against severe COVID-19.

Reduced development of COVID-19 in children reveals molecular checkpoints gating pathogenesis illuminating potential therapeutics.

The reduced development of COVID-19 for children compared to adults provides some tantalizing clues on the pathogenesis and transmissibility of this pandemic virus. First, ACE2, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) receptor, is reduced in the respiratory tract in children. Second, coronavirus associated with common colds in children may offer some protection, due to cross-reactive humoral immunity and T cell immunity between common coronaviruses and SARS-CoV-2. Third, T helper 2 immune responses are protective in children. Fourth, surprisingly, eosinophilia, associated with T helper 2, may be protective. Fifth, children generally produce lower levels of inflammatory cytokines. Finally, the influence of the downturn in the global economy, the impact of living in quarters among families who are the most at risk, and factors including the openings of some schools, are considered. Those most disadvantaged socioeconomically may suffer disproportionately with COVID-19.

Zonation in NASH - A key paradigm for understanding pathophysiology and clinical outcomes.

Non-alcoholic fatty liver disease (NAFLD) exists as a spectrum ranging from simple steatosis to histologically defined hepatocyte injury and inflammatory changes that define steatohepatitis (NASH), and increase risk for fibrosis. Although zonal differences in NASH have not been systematically studied, periportal involvement has been associated with worse metabolic outcomes and more hepatic fibrosis as compared to pericentral disease. These data suggest that hepatic zonation of disease may influence the diversity of clinical presentations. Similarly, several randomized clinical trials suggest a differential response based on zonation of disease, with preferential effects on periportal (cysteamine) or pericentral disease (obeticholic acid, pioglitazone). Intriguingly, morphogenic pathways known to affect zonal development and maintenance - WNT/ß-Catenin, Hedgehog, HIPPO/Yap/TAZ and Notch - have been implicated in NASH pathogenesis, and nuclear hormone receptors downstream of potential NASH therapeutics show zonal preferences. In this review, we summarize these data and propose that patient-specific activation of these pathways may explain the variability in clinical presentation, and the zone-specific response observed in clinical trials.

Factors associated with response, survival, and limb salvage in patients undergoing isolated limb infusion.

BACKGROUND: Isolated limb infusion (ILI) is a percutaneous method of delivering regional chemotherapy to patients with recurrent tumors of the extremity. This study determines predictors of response, survival, and limb salvage. METHODS: Single institution data from a prospective clinical trial and subsequent ILI experience were reviewed. Limb tumor burden was assessed in melanoma patients with "high" (≥10 lesions or one lesion >3 cm) or "low" burden (<10 lesions and no lesion >3 cm). Response was assessed at 3 months from ILI. RESULTS: Between 1999 and 2011, 62 patients underwent ILI (58 melanoma, 2 Merkel cell carcinoma (MCC), 2 soft tissue sarcoma (STS)). Low tumor burden patients had more complete responses (CR) (11/23, 48%) than high tumor burden (3/32, 9%, P < 0.001); they had higher 5-year survival (69% vs. 29%, P = .007). Five-year survival rates based on response: 91% CR, 53% partial response (PR), 25% less than PR (P = 0.042, CR vs. PR). 7 patients (11%) underwent amputation due to disease progression; 3 had prior CR or PR. CONCLUSIONS: Low tumor burden is a significant predictor of response in melanoma patients. Response to ILI is a significant predictor of survival. Progression of limb disease requiring amputation is not associated with any factors.

Virilization of a 46,XX Fetus Following Aromatase Inhibitor Treatment of Breast Cancer.

Virilization of the 46,XX infant may be attributed to maternal or fetoplacental origin. Maternal sources may be endogenous, as with an androgen-producing tumor, or drug-related. Iatrogenic virilization by maternal drug exposure is rarely reported, with individual case reports and case series demonstrating the effects of progesterone and other medications affecting the pituitary-ovarian axis.1-3 The class of medications known as aromatase inhibitors are recognized as effective in treating hormone receptor-positive breast cancer by preventing the conversion of androgens into estrogens by aromatase. In fetal development, placental aromatase plays a critical role in preventing virilization of the XX fetus by maternal and fetal androgens during development. In the setting of placental aromatase deficiency, the XX fetus may be virilized. It is conceivable, therefore, that maternal exposure to aromatase inhibitors early in gestation may lead to in utero virilization, though there have been no known reports of this phenomenon to date. We present a case of virilization of a 46,XX infant attributed to pharmacologic aromatase inhibition. The infant's parents provided informed consent for the reporting of this case.

Targeting allostery in the Dynein motor domain with small molecule inhibitors.

Cytoplasmic dyneins are AAA (ATPase associated with diverse cellular activities) motor proteins responsible for microtubule minus-end-directed intracellular transport. Dynein's unusually large size, four distinct nucleotide-binding sites, and conformational dynamics pose challenges for the design of potent and selective chemical inhibitors. Here we use structural approaches to develop a model for the inhibition of a well-characterized S. cerevisiae dynein construct by pyrazolo-pyrimidinone-based compounds. These data, along with functional assays of dynein motility and mutagenesis studies, suggest that the compounds inhibit dynein by engaging the regulatory ATPase sites in the AAA3 and AAA4 domains, and not by interacting with dynein's main catalytic site in the AAA1 domain. A double Walker B mutation of the AAA3 and AAA4 sites substantially reduces enzyme activity, suggesting that targeting these regulatory domains is sufficient to inhibit dynein. Our findings reveal how chemical inhibitors can be designed to disrupt allosteric communication across dynein's AAA domains.

Using chemical inhibitors to probe AAA protein conformational dynamics and cellular functions.

The AAA proteins are a family of enzymes that play key roles in diverse dynamic cellular processes, ranging from proteostasis to directional intracellular transport. Dysregulation of AAA proteins has been linked to several diseases, including cancer, suggesting a possible therapeutic role for inhibitors of these enzymes. In the past decade, new chemical probes have been developed for AAA proteins including p97, dynein, midasin, and ClpC1. In this review, we discuss how these compounds have been used to study the cellular functions and conformational dynamics of AAA proteins. We discuss future directions for inhibitor development and early efforts to utilize AAA protein inhibitors in the clinical setting.

Analyzing Resistance to Design Selective Chemical Inhibitors for AAA Proteins.

Drug-like inhibitors are often designed by mimicking cofactor or substrate interactions with enzymes. However, as active sites are comprised of conserved residues, it is difficult to identify the critical interactions needed to design selective inhibitors. We are developing an approach, named RADD (resistance analysis during design), which involves engineering point mutations in the target to generate active alleles and testing compounds against them. Mutations that alter compound potency identify residues that make key interactions with the inhibitor and predict target-binding poses. Here, we apply this approach to analyze how diaminotriazole-based inhibitors bind spastin, a microtubule-severing AAA (ATPase associated with diverse cellular activities) protein. The distinct binding poses predicted for two similar inhibitors were confirmed by a series of X-ray structures. Importantly, our approach not only reveals how selective inhibition of the target can be achieved but also identifies resistance-conferring mutations at the early stages of the design process.

Impact of a Structured Reporting Template on Adherence to Prostate Imaging Reporting and Data System Version 2 and on the Diagnostic Performance of Prostate MRI for Clinically Significant Prostate Cancer.

PURPOSE: The aim of this study was to assess the impact of a structured reporting template on adherence to the Prostate Imaging Reporting and Data System (PI-RADS) version 2 lexicon and on the diagnostic performance of prostate MRI to detect clinically significant prostate cancer (CS-PCa). METHODS: An imaging database was searched for consecutive patients who underwent prostate MRI followed by MRI-ultrasound fusion biopsy from October 2015 through October 2017. The initial MRI reporting template used included only subheadings. In July 2016, the template was changed to a standardized PI-RADS-compliant structured template incorporating dropdown menus. Lesion, patient characteristics, pathology, and adherence to the PI-RADS lexicon were extracted from MRI reports and patient charts. Diagnostic performance of prostate MRI to detect CS-PCa using combined ultrasound-MRI fusion and systematic biopsy as a reference standard was assessed. RESULTS: Three hundred twenty-four lesions in 202 patients (average age, 67 years; average prostate-specific antigen level, 5.9 ng/mL) were analyzed, including 217 MRI peripheral zone (PZ) lesions, 84 MRI non-PZ lesions, and 23 additional PZ lesions found on systematic biopsy but missed on MRI. Thirty-three percent (106 of 324) were CS-PCa. Adherence to the PI-RADS lexicon improved from 32.9% (50 of 152) to 88.4% (152 of 172) (P < .0001) after introduction of the structured template. The sensitivity of prostate MRI for CS-PCa in the PZ increased from 53% to 70% (P = .011). There was no significant change in specificity (60% versus 55%, P = .458). CONCLUSIONS: A structured template with dropdown menus incorporating the PI-RADS lexicon and classification rules improves adherence to PI-RADS and may increase the diagnostic performance of prostate MRI for CS-PCa.

Rare pancreatic tumors.

In this review, we will focus on rare pancreatic tumors. Most of these tumors do not have distinct characteristic appearances so the key to diagnosis requires a combination of imaging appearance, laboratory data, patient demographics, and associated medical syndromes in order to narrow the differential diagnosis. Nonetheless, imaging plays a vital role in narrowing the differential and guiding management. While there are many variant pathologic entities that cannot be encompassed by a single review, we aim to illustrate the imaging appearance of less common pancreatic tumors highlighting key distinctive diagnostic characteristics and discuss the implications for management. While there is overlap in the imaging appearances of many of these entities, for educational purposes, lesions will be categorized into solid (hypoenhancing and hyperenhancing), cystic lesions, mesenchymal neoplasms, and neoplasms seen in younger patients (< 40 years).

Irreversible electroporation of pancreatic adenocarcinoma: a primer for the radiologist.

Irreversible electroporation (IRE) is increasingly used for the ablation of unresectable locally advanced pancreatic adenocarcinoma. Unlike other ablation technologies that cannot be safely used around critical vasculature or ducts for risk of thermal damage, IRE uses high-voltage pulses to disrupt cellular membranes. This causes cell death by apoptosis and inflammation. IRE has been deployed by both open and percutaneous approaches. Generator parameters are the same for both approaches, and settings are pancreas specific. Variations in settings, probe placement, and probe exposure can result in thermal damage or reversible electroporation and resultant treatment failure, morbidity, or mortality. When used properly, IRE appears to improve overall survival and local recurrence, but does not influence the rate of distant recurrence. However, studies of both open and percutaneous approaches have been relatively small, non-controlled, and without appropriate comparisons. It is challenging for the radiologist to interpret treatment effects after IRE because of a dearth of guiding literature and pathologic correlates. This primer describes technical aspects, pathology correlates, post-IRE imaging, and outcomes for percutaneous and open approaches.

Resection of Locally Advanced Pancreatic Cancer without Regression of Arterial Encasement After Modern-Era Neoadjuvant Therapy.

INTRODUCTION: Modern-era systemic therapy for locally advanced pancreatic adenocarcinoma (LAPC) offers improved survival relative to historical regimens but not necessarily improved radiographic downstaging to allow more patients to undergo resection. The aim of this study was to evaluate the survival, progression, and pathologic outcomes after resection of LAPC that did not regress from > 180 degrees arterial encasement after neoadjuvant therapy. METHODS: Sixty-one LAPC patients were brought to the operating room after neoadjuvant therapy for NCCN-defined unresectable pancreatic cancer between 2012 and 2017. Pts were explored with intent of pancreatectomy and irreversible electroporation for margin extension; 5 (8%) had metastatic lesions on exploratory laparoscopy and were excluded from analyses. Imaging was re-examined to confirm LAPC prior to surgery. Data were analyzed from a prospective pancreatic cancer database. RESULTS: Patients had arterial involvement of the celiac axis (37.5%) and/or superior mesenteric artery (42.9%) and/or an extended length of the common hepatic (n = 44.6%) artery. Twenty-nine males and 27 females, median 65 years of age, received neoadjuvant gemcitabine-based (58.9%) or FOLFIRINOX (35.7%) chemotherapy and stereotactic body (42.9%) or intensity-modulated (51.8%) radiation therapy. Median months from initiation of neoadjuvant therapy to surgery was 7.5. Sixty-one percent underwent Whipple, 21% distal, and 18% modified Appleby procedures; 57% patients underwent venous reconstruction. Ninety-day mortality was 2%. An R0 margin was achieved in 80%, and 53% were N0. Median overall and progression-free survival was 18.5 (95%CI 12.27-32.33) and 8.5 months (95%CI 6.0-15.0), respectively. One- and 3-year survival from surgery was 68.5% (95%CI 53.0-79.7) and 39.0% (95%CI 23.7-53.8), respectively. CONCLUSION: With modern-era neoadjuvant therapy, R0 resections can be achieved in a majority of non-metastatic patients with locally advanced, unresectable disease based on cross-sectional imaging.

Intravenous Contrast-Induced Nephropathy-The Rise and Fall of a Threatening Idea.

Contrast-induced nephropathy (CIN) has been considered to be a cause of renal failure for over 50 years, but careful review of past and recent studies reveals the risks of CIN to be overestimated. Older studies frequently cited the use of high-osmolality contrast media, which have since been replaced by low-osmolality contrast media, which have lower risks for nephropathy. In addition, literature regarding CIN typically describes the incidence following cardiac angiography, whereas the risk of CIN from intravenous injection is much lower. Most of the early published literature also lacked appropriate control groups to compare to those that received iodinated contrast, and thus attributed rises in creatinine to intravenous contrast without considering normal creatinine fluctuations (frequent in patients with kidney disease) and other acute pathologic states such as hypotension or nephrotoxic drug administration. The aim of this paper is to review the literature detailing CIN risk, discuss why CIN risk is often overestimated and how withholding contrast can lead to misdiagnosis and delay in appropriate patient management.

Imaging of pancreatic cancer: what the surgeon wants to know.

Pancreatic cancer is the fourth leading cause of cancer-related death. Early detection is challenging because symptoms are relatively nonspecific. Imaging is vital in detecting and staging pancreatic tumors, and management depends on imaging findings. Radiologists should be aware of current surgical treatments for pancreatic neoplasms, as surgeons rely on interpretation of cross-sectional imaging for presurgical planning. Understanding postsurgical anatomy is critical to assess for complications and recurrence. This review will emphasize the role of the radiologist in planning for surgery and will review postoperative changes based on surgical intervention and common complications.

Chemical structure-guided design of dynapyrazoles, cell-permeable dynein inhibitors with a unique mode of action.

Cytoplasmic dyneins are motor proteins in the AAA+ superfamily that transport cellular cargos toward microtubule minus-ends. Recently, ciliobrevins were reported as selective cell-permeable inhibitors of cytoplasmic dyneins. As is often true for first-in-class inhibitors, the use of ciliobrevins has in part been limited by low potency. Moreover, suboptimal chemical properties, such as the potential to isomerize, have hindered efforts to improve ciliobrevins. Here, we characterized the structure of ciliobrevins and designed conformationally constrained isosteres. These studies identified dynapyrazoles, inhibitors more potent than ciliobrevins. At single-digit micromolar concentrations dynapyrazoles block intraflagellar transport in the cilium and lysosome motility in the cytoplasm, processes that depend on cytoplasmic dyneins. Further, we find that while ciliobrevins inhibit both dynein's microtubule-stimulated and basal ATPase activity, dynapyrazoles strongly block only microtubule-stimulated activity. Together, our studies suggest that chemical-structure-based analyses can lead to inhibitors with improved properties and distinct modes of inhibition.

Cytoplasmic Dynein Antagonists with Improved Potency and Isoform Selectivity.

Cytoplasmic dyneins 1 and 2 are related members of the AAA+ superfamily (ATPases associated with diverse cellular activities) that function as the predominant minus-end-directed microtubule motors in eukaryotic cells. Dynein 1 controls mitotic spindle assembly, organelle movement, axonal transport, and other cytosolic, microtubule-guided processes, whereas dynein 2 mediates retrograde trafficking within motile and primary cilia. Small-molecule inhibitors are important tools for investigating motor protein-dependent mechanisms, and ciliobrevins were recently discovered as the first dynein-specific chemical antagonists. Here, we demonstrate that ciliobrevins directly target the heavy chains of both dynein isoforms and explore the structure-activity landscape of these inhibitors in vitro and in cells. In addition to identifying chemical motifs that are essential for dynein blockade, we have discovered analogs with increased potency and dynein 2 selectivity. These antagonists effectively disrupt Hedgehog signaling, intraflagellar transport, and ciliogenesis, making them useful probes of these and other cytoplasmic dynein 2-dependent cellular processes.

Incorporating the principles of the patient-centered medical home into a student-run free clinic.

As the health care delivery landscape changes, medical schools must develop creative strategies for preparing future physicians to provide quality care in this new environment. Despite the growing prominence of the patient-centered medical home (PCMH) as an effective model for health care delivery, few medical schools have integrated formal education on the PCMH into their curricula. Incorporating the PCMH model into medical school curricula is important to ensure that students have a comprehensive understanding of the different models of health care delivery and can operate effectively as physicians. The authors provide a detailed description of the process by which the Weill Cornell Community Clinic (WCCC), a student-run free clinic, has integrated PCMH principles into a service-learning initiative. The authors assessed patient demographics, diagnoses, and satisfaction along with student satisfaction. During the year after a PCMH model was adopted, 112 students and 19 licensed physicians volunteered their time. A review of the 174 patients seen from July 2011 to June 2012 found that the most common medical reasons for visits included management of hypertension, hyperlipidemia, diabetes, gastrointestinal conditions, arthritis, anxiety, and depression. During the year after the adoption of the PCMH model, 87% were very or extremely satisfied with their care, and 96% of the patients would recommend the WCCC to others. Students who participate in the WCCC gain hands-on experience in coordinating care, providing continuity of care, addressing issues of accessibility, and developing quality and safety metrics. The WCCC experience provides an integrative model that links service-learning with education on health care delivery in a primary care setting. The authors propose that adoption of this approach by other student-run clinics provides a substantial opportunity to improve medical education nationwide and better prepare future physicians to practice within this new model of health care delivery.

Direct kinetochore-spindle pole connections are not required for chromosome segregation.

Segregation of genetic material occurs when chromosomes move to opposite spindle poles during mitosis. This movement depends on K-fibers, specialized microtubule (MT) bundles attached to the chromosomes' kinetochores. A long-standing assumption is that continuous K-fibers connect every kinetochore to a spindle pole and the force for chromosome movement is produced at the kinetochore and coupled with MT depolymerization. However, we found that chromosomes still maintained their position at the spindle equator during metaphase and segregated properly during anaphase when one of their K-fibers was severed near the kinetochore with a laser microbeam. We also found that, in normal fully assembled spindles, K-fibers of some chromosomes did not extend to the spindle pole. These K-fibers connected to adjacent K-fibers and/or nonkinetochore MTs. Poleward movement of chromosomes with short K-fibers was uncoupled from MT depolymerization at the kinetochore. Instead, these chromosomes moved by dynein-mediated transport of the entire K-fiber/kinetochore assembly. Thus, at least two distinct parallel mechanisms drive chromosome segregation in mammalian cells.

A biomolecule-compatible visible-light-induced azide reduction from a DNA-encoded reaction-discovery system.

Using a system that accelerates the serendipitous discovery of new reactions by evaluating hundreds of DNA-encoded substrate combinations in a single experiment, we explored a broad range of reaction conditions for new bond-forming reactions. We discovered reactivity that led to a biomolecule-compatible, Ru(II)-catalysed azide-reduction reaction induced by visible light. In contrast to current azide-reduction methods, this reaction is highly chemoselective and is compatible with alcohols, phenols, acids, alkenes, alkynes, aldehydes, alkyl halides, alkyl mesylates and disulfides. The remarkable functional group compatibility and mild conditions of the reaction enabled the azide reduction of nucleic acid and oligosaccharide substrates, with no detectable occurrence of side reactions. The reaction was also performed in the presence of a protein enzyme without the loss of enzymatic activity, in contrast to two commonly used azide-reduction methods. The visible-light dependence of this reaction provides a means of photouncaging functional groups, such as amines and carboxylates, on biological macromolecules without using ultraviolet irradiation.

Free-solution oligonucleotide separation in nanoscale channels.

In this paper, we report an experimental study of electrokinetic transport and separation of double-stranded deoxyribonucleic acid (dsDNA) oligonucleotides in custom-fabricated fused-silica nanochannels filled with a gel-free sodium borate aqueous buffer. Mixtures of fluorescently labeled dsDNA molecules in the range of 10-100 base pair (bp), fluorescein, and fluorescein-12-UTP (UTP) were separated in less than 120 s in channels of depth ranging from 40 to 1560 nm. We varied the channel depth and background buffer concentration to achieve a 0.006-0.2 range of Debye length-to-channel-half-depth ratio (lambdaD/h), and a 0.004-1.7 range of the ratio of length of dsDNA molecule to channel half-depth (l/h). We find observed oligonucleotide migration times depend on both l/h and lambdaD/h. Electrophoretic mobility estimates agree well with published (micrometer-scale channel) values for background electrolyte (BGE) concentrations greater than approximately 10 mM. At BGE concentrations of 1 and 5 mM, mobility estimates in our nanochannels are higher than published values. Of the cases studied, the highest separation sensitivities were achieved in 100 nm channels with 1-10 mM ion density buffers. Potential applications of this technology include rapid small-scale sequencing and other fluorescence-based oligonucleotide separation and detection assays.