Solid-phase XRN1 reactions for RNA cleavage: application in single-molecule sequencing.

Modifications in RNA are numerous (∼170) and in higher numbers compared to DNA (∼5) making the ability to sequence an RNA molecule to identify these modifications highly tenuous using next generation sequencing (NGS). The ability to immobilize an exoribonuclease enzyme, such as XRN1, to a solid support while maintaining its activity and capability to cleave both the canonical and modified ribonucleotides from an intact RNA molecule can be a viable approach for single-molecule RNA sequencing. In this study, we report an enzymatic reactor consisting of covalently attached XRN1 to a solid support as the groundwork for a novel RNA exosequencing technique. The covalent attachment of XRN1 to a plastic solid support was achieved using EDC/NHS coupling chemistry. Studies showed that the solid-phase digestion efficiency of model RNAs was 87.6 ± 2.8%, while the XRN1 solution-phase digestion for the same model was 78.3 ± 4.4%. The ability of immobilized XRN1 to digest methylated RNA containing m6A and m5C ribonucleotides was also demonstrated. The processivity and clipping rate of immobilized XRN1 secured using single-molecule fluorescence measurements of a single RNA transcript demonstrated a clipping rate of 26 ± 5 nt s-1 and a processivity of >10.5 kb at 25°C.

carba-Nucleopeptides (cNPs): A Biopharmaceutical Modality Formed through Aqueous Rhodamine†B Photoredox Catalysis.

Exchanging the ribose backbone of an oligonucleotide for a peptide can enhance its physiologic stability and nucleic acid binding affinity. Ordinarily, the eneamino nitrogen atom of a nucleobase is fused to the side chain of a polypeptide through a new C-N bond. The discovery of C-C linked nucleobases in the human transcriptome reveals new opportunities for engineering nucleopeptides that replace the traditional C-N bond with a non-classical C-C bond, liberating a captive nitrogen atom and promoting new hydrogen bonding and π-stacking interactions. We report the first late-stage synthesis of C-C linked carba-nucleopeptides (cNPs) using aqueous Rhodamine B photoredox catalysis. We prepare brand-new cNPs in batch, in parallel, and in flow using three long-wavelength photochemical setups. We detail the mechanism of our reaction by experimental and computational studies and highlight the essential role of diisopropylethylamine as a bifurcated two-electron reductant.

REVISED CLASSIFICATION OF THE OPTICAL COHERENCE TOMOGRAPHY OUTER RETINAL BANDS BASED ON CENTRAL SEROUS CHORIORETINOPATHY ANALYSIS.

PURPOSE: To evaluate the optical coherence tomography (OCT) imaging findings in recent onset neurosensory retinal detachments induced by central serous chorioretinopathy and to attempt to corroborate these findings with proposed anatomical correlates. METHODS: Retinal detachments due to central serous chorioretinopathy of less than 3 months' duration and the surrounding area were scanned with OCT. The imaging of the outer retinal bands was evaluated according to proposals by Cuenca et al and the IN•OCT Consensus classification. RESULTS: Optical coherence tomography findings in 11 eyes (11 patients) with CSC showed that all hyperreflective bands above Band 4 were variably continuous within the outer portion of the serous detachment. We then attempted to reconcile inconsistencies in current explanations for the outer retinal bands to propose changes to the outer retinal OCT nomenclature. CONCLUSION: Our patients' OCT findings support the current standard that Band 3 is an outer retinal structure and that Band 4 represents the retinal pigment epithelium/Bruch complex. Confusion exists regarding whether the interdigitation zone extends halfway up or for the full length of the outer segments, and the hyporeflective band between Bands 3 and 4 has yet to receive an appropriate term. We therefore propose a modification to the IN•OCT Consensus classification by renaming the trilaminar hyporeflective, hyperreflective, and hyporeflective bands between Bands 2 and 4 as the outer segment-interdigitation zone complex consisting of the inner, middle, and outer segment-interdigitation zone, respectively.

Fetal Tachycardia in the Setting of Maternal Intrapartum Fever and Perinatal Morbidity.

OBJECTIVE: The fetal consequences of intrapartum fetal tachycardia with maternal fever or clinical chorioamnionitis are not well studied. We evaluated the association between perinatal morbidity and fetal tachycardia in the setting of intrapartum fever. STUDY DESIGN: Secondary analysis of a multicenter randomized control trial that enrolled 5,341 healthy laboring nulliparous women ≥36 weeks' gestation. Women with intrapartum fever ≥ 38.0°C (including those meeting criteria for clinical chorioamnionitis) after randomization were included in this analysis. Isolated fetal tachycardia was defined as fetal heart rate (FHR) ≥160 beats per minute for at least 10 minutes in the absence of other FHR abnormalities. FHR abnormalities other than tachycardia were excluded from the analysis. The primary outcome was a perinatal composite (5-minute Apgar's score ≤3, intubation, chest compressions, or mortality). Secondary outcomes included low arterial cord pH (pH < 7.20), base deficit ≥12, and cesarean delivery. RESULTS: A total of 986 (18.5%) of women in the trial developed intrapartum fever, and 728 (13.7%) met criteria to be analyzed; of these, 728 women 336 (46.2%) had maternal-fetal medicine (MFM) reviewer-defined fetal tachycardia, and 349 of the 550 (63.5%) women during the final hour of labor had validated software (PeriCALM) defined fetal tachycardia. After adjusting for confounders, isolated fetal tachycardia was not associated with a significant difference in the composite perinatal outcome (adjusted odds ratio [aOR] = 3.15 [0.82-12.03]) compared with absence of tachycardia. Fetal tachycardia was associated with higher odds of arterial cord pH <7.2, aOR = 1.48 (1.01-2.17) and of infants with a base deficit ≥ 12, aOR = 2.42 (1.02-5.77), but no significant difference in the odds of cesarean delivery, aOR = 1.33 (0.97-1.82). CONCLUSION: Fetal tachycardia in the setting of intrapartum fever or chorioamnionitis is associated with significantly increased fetal acidemia defined as a pH <7.2 and base excess ≥12 but not with a composite perinatal morbidity. KEY POINTS: · The perinatal outcomes associated with fetal tachycardia in the setting of maternal fever are undefined.. · Fetal tachycardia was not significantly associated with perinatal morbidity although the sample size was limited.. · Fetal tachycardia was associated with an arterial cord pH <7.2 and base deficit of 12 or greater..

Age-Friendly Universities (AFU): Possibilities and Power in Campus Connections.

Shifting age demographics are reshaping societies and challenging institutions of higher education to respond to aging populations through new approaches to teaching, research, and community engagement. The Age-Friendly University (AFU) initiative offers a set of guiding principles institutions can use to assess the extent to which their programs and practices are age inclusive, as well as identify gaps and opportunities. However, institutions need guiding change models to help them mount more comprehensive, integrated age-friendly efforts. Hirschhorn and May's campaign approach to change in higher education offers one such model. Drawing on its four core elements (i.e., "listen in" to the institution, develop a strategic theme, sweep people in, build the infrastructure), the present paper shows how AFU partners are working to move their age-friendly efforts across their campuses by building connections, coalitions, and partnerships. It is argued that such relationships are essential for achieving and sustaining an institution's age-friendly vision.

Site-Selective Approach to ß-Fluorination: Photocatalyzed Ring Opening of Cyclopropanols.

To expand upon the recent pioneering reports of catalyzed sp(3) C-H fluorination methods, the next rational step is to focus on directing "radical-based fluorination" more effectively. One potential solution entails selective C-C bond activation as a prelude to selective fluorination. Herein, we report the tandem photocatalyzed ring-opening/fluorination reactions of cyclopropanols by 1,2,4,5-tetracyanobenzene (TCB) and Selectfluor to afford a process tantamount to site-selective ß-fluorination of carbonyl-containing compounds. This new approach provides a synthetically mild and operationally simple route to otherwise difficult-to-prepare ß-fluorinated products in good yields and with good-to-excellent regioselectivity. Remarkably, substrates that contain other usually reactive (e.g., benzylic) sites undergo ring-opening fluorination preferably. The versatility of this method to give cyclic ß-fluorides from tertiary cyclopropanols and γ-fluoro alcohols is also highlighted.

Direct, catalytic monofluorination of sp³ C-H bonds: a radical-based mechanism with ionic selectivity.

Recently, our group unveiled a system in which an unusual interplay between copper(I) and Selectfluor effects mild, catalytic sp(3) C-H fluorination. Herein, we report a detailed reaction mechanism based on exhaustive EPR, (19)F NMR, UV-vis, electrochemical, kinetic, synthetic, and computational studies that, to our surprise, was revealed to be a radical chain mechanism in which copper acts as an initiator. Furthermore, we offer an explanation for the notable but curious preference for monofluorination by ascribing an ionic character to the transition state.

A chelating nucleophile plays a starring role: 1,8-naphthyridine-catalyzed polycomponent α,α-difluorination of acid chlorides.

A dually activated ketene enolate, generated from an acid chloride, the unusual chelating nucleophile (1,8-naphthyridine), and a Lewis acid, reacts to afford a host of α,α-difluorinated products in the presence of a benchtop-stable fluorinating agent (Selectfluor). The use of this method to synthesize otherwise difficult to make products is highlighted along with computational and spectroscopic support for the proposed chelate.

Aqueous levels of fluocinolone acetonide after administration of fluocinolone acetonide inserts or fluocinolone acetonide implants.

PURPOSE: To compare aqueous levels of fluocinolone acetonide (FAc) after administration of FAc inserts or FAc implants (Retisert; Bausch & Lomb, Rochester, NY). DESIGN: Comparison of pharmacokinetics from 2 prospective, interventional, clinical trials. PARTICIPANTS: Thirty-seven patients with diabetic macular edema (DME) (Fluocinolone Acetonide in Human Aqueous [FAMOUS] Study, C-01-06-002) and 7 patients with uveitis (NA-00019318). METHODS: Aqueous FAc was measured after administration of FAc implants or 0.2 µg/day (low dose, ILUVIEN; Alimera Sciences Inc., Alpharetta, GA) or 0.5 µg/day (high dose) FAc inserts. MAIN OUTCOME MEASURES: The primary end point was aqueous levels of FAc. RESULTS: At 1 month after administration for subjects who received 1 treatment, mean aqueous FAc levels were 2.17 (low dose) and 3.03 ng/ml (high dose) for FAc inserts and 6.12 ng/ml for FAc implants with maximum levels of 3.83, 6.66, and 13.50 ng/ml, respectively. At 3 months, mean FAc levels were 1.76, 2.15, and 6.12 ng/ml, respectively. Between 6 and 36 months after low-dose inserts, aqueous levels of FAc were remarkably stable, ranging from 1.18 to 0.45 ng/ml. After high-dose inserts, mean FAc levels were stable between 6 and 24 months, ranging from 1.50 to 0.84 ng/ml and then decreasing to 0.35 ng/ml at 30 months and 0.15 ng/ml at 36 months. In implant-containing eyes, mean FAc levels remained >6 ng/ml through 15 months, the last time point with measurements from at least 6 eyes. CONCLUSIONS: Low- and high-dose FAc inserts both provide stable long-term release of FAc with comparable peak levels in the aqueous: slightly >2 ng/ml for approximately 3 months followed by steady-state levels between 1.0 and 0.5 ng/ml through 36 months for low-dose inserts versus levels between 1.5 and 1.1 ng/ml through 24 months for high-dose inserts. Steady-state aqueous levels after FAc implants were >6 ng/ml. These results provide new insights that aid in the interpretation of efficacy trials and indicate that there is a dose effect for steroid-induced ocular hypertension. In susceptible patients, prolonged aqueous levels of FAc >1 ng/ml moderately increased the risk of glaucoma and levels >6 ng/ml posed a markedly increase risk.

Metal-catalyzed benzylic fluorination as a synthetic equivalent to 1,4-conjugate addition of fluoride.

We explore in detail the iron-catalyzed benzylic fluorination of substrates containing aromatic rings and electron-withdrawing groups positioned ß to one another, thus providing direct access to ß-fluorinated adducts. This operationally convenient process can be thought of not only as a contribution to the timely problem of benzylic fluorination but also as a functional equivalent to a conjugate addition of fluoride, furnishing products in moderate to good yields and in excellent selectivity.

Origin of the diffuse vibrational signature of a cyclic intramolecular proton bond: Anharmonic analysis of protonated 1,8-disubstituted naphthalene ions.

We analyze the structures and spectral signatures of the cyclic intramolecular proton bond, N-H(+)-A, A = O and F, formed when an excess proton is added to derivatives of the 1,8-disubstituted naphthalene scaffold. These compounds provide a quasi-rigid framework with which to study the spectral complexity often associated with the N-H(+)-A entity. Vibrational spectra were obtained by monitoring photodissociation of weakly bound H2 adducts of the mass-selected ions cooled close to 10 K. Several bands across the 900-3500 cm(-1) spectral range were traced to involvement of the bridging proton by their telltale shifts upon selective H∕D isotopic substitution at that position. We account for the complex patterns that occur near the expected locations of the NH stretching fundamentals in the context of background levels mixing with a "bright" zero-order state through cubic terms in the potential energy expansion. Thus, this system provides a detailed picture of one of the mechanisms behind the line broadening often displayed by embedded excess protons. It does so in a sufficiently sparse density of states regime that many discrete transitions are observed in the vicinity of the harmonic stretching transition involving displacement of the trapped proton.

Population versus customized fetal growth norms and adverse outcomes in an intrapartum cohort.

OBJECTIVE: To compare population versus customized fetal growth norms in identifying neonates at risk for adverse outcomes (APO) associated with small for gestational age (SGA). STUDY DESIGN: Secondary analysis of an intrapartum fetal pulse oximetry trial in nulliparous women at term. Birth weight percentiles were calculated using ethnicity- and gender-specific population norms and customized norms (Gardosi). RESULTS: Of the studied neonates, 508 (9.9%) and 584 (11.3%) were SGA by population (SGApop) and customized (SGAcust) norms, respectively. SGApop infants were significantly associated with a composite adverse neonatal outcome, neonatal intensive care admission, low fetal oxygen saturation, and reduced risk of cesarean delivery; both SGApop and SGAcust infants were associated with a 5-minute Apgar score < 4. The ability of customized and population birth weight percentiles in predicting APO was poor (12 of 14 APOs had area under the curve of <0.6). CONCLUSION: In this intrapartum cohort, neither customized nor normalized population norms adequately identified neonates at risk of APO related to SGA.

Spectral and Electrochemical Properties of Common Photocatalysts in Water: A Compendium for Aqueous Photoredox Catalysis.

Electrochemical potentials of photocatalysts are solvent dependent. One of the largest discrepancies is observed when water is used in place of organic solvents as the reaction media. Unfortunately, the redox potentials for many photocatalysts in water have not been determined, at least under one unifying set of conditions, and this greatly hinders the rational design of sustainable and biocompatible photoredox reactions. Herein, we measure the spectral and electrochemical properties of the most common photoredox catalysts in water and catalog their absorption and fluorescence maxima and ground- and excited-state potentials.

Aqueous Flavin Photoredox Catalysis Drives Exclusive C3-Alkylation of Indolyl Radical Cations in Route to Unnatural Tryptophan Mimetics.

One way to build chemical diversity into indoles is to oxidize them to indolyl radical cations (Ind•+). These intermediates can accept new functional groups across C2-C3 bonds or independently at C2. Less encountered is selective diversification at C3, a position plagued by competing dearomative side reactions. We disclose an aqueous photoredox-catalyzed method for transforming Ind•+ into C3-substituted tryptophan mimetics that uses water as a transient protecting group to guide site-selective C3 alkylation.

Unilateral, Sectoral Retinal Metastasis of Small-Cell Lung Cancer Mimicking Viral Retinitis.

PURPOSE: To report a case of unilateral, sectoral retinal metastasis of small-cell lung cancer (SCLC) that mimicked cytomegalovirus (CMV) retinitis. METHOD: Case report. RESULTS: A 48-year-old woman presented with a four-week history of a visual field loss in her right eye. She had a past medical history of extensive-stage SCLC with brain metastasis, stable on maintenance atezolizumab for two years. On initial presentation, she was diagnosed with CMV retinitis. No improvement was observed with 4 weeks of oral valganciclovir. Upon referral for a second opinion, her fundus exam appeared compatible with CMV retinitis, and anterior chamber tap for polymerase chain reaction for viral etiologies was performed followed by intravitreal and intravenous ganciclovir without improvement. She was referred for a third opinion, where diagnostic vitrectomy with vitreous and retinal biopsies were consistent with SCLC metastatic to the retina. The patient underwent enucleation of the right eye for definitive pathologic analysis and subsequently was started on additional systemic chemotherapy. CONCLUSION: Retinal metastases are exceedingly rare, particularly retinal metastasis of SCLC. Retinal metastasis should be considered in patients initially diagnosed with viral retinitis who fail to improve despite antiviral therapy, particularly if they have a known history of malignancy. Furthermore, retinal metastasis of SCLC potentially could be misdiagnosed histopathologically as retinoblastoma if the patient's history is unknown and appropriate immunohistochemical stains are not performed.

A novel point-of-care test for cirrhosis based on dimeric to monomeric IgA ratio in blood: a pilot cohort study.

BACKGROUND AND AIMS: Dimeric IgA to monomeric IgA ratio (dIgA ratio) is a biomarker of gut mucosal leakage in liver cirrhosis. We evaluated the diagnostic performance of a novel point-of-care (POC) dIgA ratio test for cirrhosis. METHODS: Plasma samples from people with chronic liver disease were analyzed using the BioPoint POC dIgA ratio antigen immunoassay lateral flow test. Cirrhosis was defined by Fibroscan>12.5 kPa, clinical evidence of cirrhosis or liver histopathology. POC dIgA test diagnostic accuracy was determined in a test cohort using receiver operating characteristic curve analysis; optimal cutoffs for sensitivity and specificity were then applied to a validation cohort. RESULTS: A total of 1478 plasma samples from 866 patients with chronic liver disease were included (test cohort n = 260, validation cohort n = 606). In all, 32% had cirrhosis; 44% Child-Pugh A, 26% Child-Pugh B, and 29% Child-Pugh C. Median POC dIgA ratio was higher in cirrhosis (0.9) compared with no cirrhosis (0.4, p < 0.001), and in Child-Pugh class B/C compared with A cirrhosis (1.4 Child-Pugh B/C vs. 0.6 Child-Pugh A, p < 0.001). POC dIgA ratio test had good diagnostic accuracy for liver cirrhosis in the test cohort (area under the receiver operating characteristic curve=0.80); a dIgA ratio cutoff of 0.6 had a sensitivity of 74% and specificity of 86%. POC dIgA test accuracy was moderate in the validation cohort (area under the receiver operating characteristic curve=0.75; positive predictive value 64%, negative predictive value 83%). Using a dual cutoff approach, 79% of cirrhosis cases were correctly diagnosed and further testing was avoided in 57%. CONCLUSIONS: POC dIgA ratio test had moderate accuracy for cirrhosis. Further studies evaluating the accuracy of POC dIgA ratio testing for cirrhosis screening are warranted.

Timing of delivery and pregnancy outcomes among laboring nulliparous women.

OBJECTIVE: The objective of the study was to compare pregnancy outcomes by completed week of gestation after 39 weeks with outcomes at 39 weeks. STUDY DESIGN: Secondary analysis of a multicenter trial of fetal pulse oximetry in spontaneously laboring or induced nulliparous women at a gestation of 36 weeks or longer. Maternal outcomes included a composite (treated uterine atony, blood transfusion, and peripartum infections) and cesarean delivery. Neonatal outcomes included a composite of death, neonatal respiratory and other morbidities, and neonatal intensive care unit admission. RESULTS: Among the 4086 women studied, the risks of the composite maternal outcome (P value for trend < .001), cesarean delivery (P < .001), and composite neonatal outcome (P = .047) increased with increasing gestational age from 39 to 41 or more completed weeks. Adjusted odds ratios (95% confidence interval) for 40 and 41 or more weeks, respectively, compared with 39 weeks were 1.29 (1.03-1.64) and 2.05 (1.60-2.64) for composite maternal outcome, 1.28 (1.05-1.57) and 1.75 (1.41-2.16) for cesarean delivery, and 1.25 (0.86-1.83) and 1.37 (0.90-2.09) for composite neonatal outcome. CONCLUSION: Risks of maternal morbidity and cesarean delivery but not neonatal morbidity increased significantly beyond 39 weeks.

Interaction of a C-F bond with the π-system of a C═C bond or "head on" with a proximate C-H bond.

We describe the synthesis and preliminary study of two molecules, in which a fluorine atom is positioned proximately above the π-orbitals of a C═C bond or else wherein a C-F bond interacts in a "head on" fashion with a proximate C-H bond. The spectroscopic characteristics of these unusual interactions are documented, X-ray crystallographic analyses are reported, and theoretical calculations are employed to support the observed spectroscopy.

Characterization of highly unusual NH+-O hydrogen bonding to ester ether oxygen atoms through spectroscopic and computational studies.

We characterize a highly unusual, charged NH-O hydrogen bond formed within esters of 8-(dimethylamino)naphthalen-1-ol in which an ammonium ion serves as an intramolecular hydrogen bond donor to spatially proximate ester ether oxygen atoms. Infrared spectroscopic analysis of the ester carbonyl frequencies demonstrates significant blue-shifting when ether hydrogen bonding is possible, in stark contrast to the more commonly observed red shift that occurs upon hydrogen bonding to the ester carbonyl oxygen. The intrinsic behavior of the linkage (i.e., in which counterions and solvent effects are eliminated) is provided by vibrational predissociation spectroscopy of the isolated gas-phase cations complexed with weakly bound D(2) molecules.

Relationship between fetal station and successful vaginal delivery in nulliparous women.

OBJECTIVE: To study the relationship between fetal station and successful vaginal delivery in nulliparous women. STUDY DESIGN: This was a secondary analysis from a previously reported trial of pulse oximetry. Vaginal delivery rates were evaluated and compared with respect to the fetal station. Spontaneous labor and induction of labor groups were evaluated separately. Multivariable logistic regression analysis was performed to adjust for confounding factors. RESULTS: Successful vaginal delivery was more frequent with an engaged vertex for spontaneous labor (86.2% versus 78.6%; p = 0.01) and induced labor (87.7% versus 66.1%; p < 0.01). After adjustment, engaged fetal vertex was not associated with vaginal delivery for spontaneous labor (odds ratio [OR] 1.5; 95% confidence interval [CI] 0.95 to 2.3; p = 0.08) or for women with induced labor (OR 2.2; 95% CI 0.96 to 5.1; p = 0.06). CONCLUSION: Among nulliparous women enrolled in the FOX randomized trial in spontaneous labor or for labor induction, an engaged fetal vertex does not affect their vaginal delivery rate.