A molecular switch for neuroprotective astrocyte reactivity.

The intrinsic mechanisms that regulate neurotoxic versus neuroprotective astrocyte phenotypes and their effects on central nervous system degeneration and repair remain poorly understood. Here we show that injured white matter astrocytes differentiate into two distinct C3-positive and C3-negative reactive populations, previously simplified as neurotoxic (A1) and neuroprotective (A2)1,2, which can be further subdivided into unique subpopulations defined by proliferation and differential gene expression signatures. We find the balance of neurotoxic versus neuroprotective astrocytes is regulated by discrete pools of compartmented cyclic adenosine monophosphate derived from soluble adenylyl cyclase and show that proliferating neuroprotective astrocytes inhibit microglial activation and downstream neurotoxic astrocyte differentiation to promote retinal ganglion cell survival. Finally, we report a new, therapeutically tractable viral vector to specifically target optic nerve head astrocytes and show that raising nuclear or depleting cytoplasmic cyclic AMP in reactive astrocytes inhibits deleterious microglial or macrophage cell activation and promotes retinal ganglion cell survival after optic nerve injury. Thus, soluble adenylyl cyclase and compartmented, nuclear- and cytoplasmic-localized cyclic adenosine monophosphate in reactive astrocytes act as a molecular switch for neuroprotective astrocyte reactivity that can be targeted to inhibit microglial activation and neurotoxic astrocyte differentiation to therapeutic effect. These data expand on and define new reactive astrocyte subtypes and represent a step towards the development of gliotherapeutics for the treatment of glaucoma and other optic neuropathies.

Killer Phonon Caught: Femtosecond Stimulated Raman Spectroscopy Identifies Phonon-Induced Control of Photophysics in Rubrene Derivatives.

Molecular reaction coordinates are defined by the interplay of a number of orthogonal nuclear coordinates and are inherently multidimensional for large molecules. Identifying how specific nuclear motions along these reaction coordinates can be used to drive and control chemical processes is a promising approach for the optimization of chemical outcomes and targeted synthetic design. Here, we used femtosecond stimulated Raman spectroscopy (FSRS) to quantify the effects of individual phonon nuclear motions on singlet fission in rubrene derivatives. Rubrene readily undergoes singlet fission and is amendable to chemical derivatization, yet the factors that impact the singlet fission yield are not fully understood. Crystal packing is known to play a significant role in both fission and carrier transport, and thus, we focused on the impact of phonon nuclear motions on the photophysics. We used four halogen-substituted rubrene crystals and successfully identified one specific phonon mode that suppresses singlet fission in these crystals. We used FSRS with single-pulse excitation and double-pulse excitation to coherently amplify each phonon mode and quantify its effects on the excited-state process. We found that coherent amplification of the specific phonon vibration involving twisting of the peripheral phenyl rings and tetracene core motions resulted in less ground-state depletion and fewer triplet state absorption. Our study demonstrated that it is possible to use coherent phonon excitation to influence the photophysical outcome, while also showing that FSRS with double-pulse excitation can be a successful tool for quantifying mode-selective contributions to photophysics.

Microwave and Computational Study of Pivalic Sulfuric Anhydride and the Pivalic Acid Monomer: Mechanistic Insights into the RCOOH + SO3 Reaction.

The microwave spectrum of pivalic sulfuric anhydride, (CH3)3CCOOSO2OH (PivSA), has been observed by rotational spectroscopy. The compound was formed by the reaction of SO3 with (CH3)3CCOOH (pivalic acid) in a supersonic jet in a manner analogous to that previously observed with other carboxylic acids. Computational analysis indicates that the reaction is best described as a pericyclic process coupled with a 60° rotation of the t-butyl group. Product formation can occur through either a sequential (two-step) or a concerted (one-step) pathway. The former involves an internal rotation of the t-butyl group through a 0.11 kcal/mol barrier followed by the pericyclic reaction that joins the moieties. The latter passes through a second-order saddle point in which the internal rotation and pericyclic reaction occur simultaneously. This path is the most energetically favorable, as the zero-point corrected energy at the saddle point structure is 0.16 kcal/mol below that of a putative (CH3)3CCOOH-SO3 precursor complex. Additional computational work involving a series of carboxylic acids is reported, which explores the effects of gas-phase acidity and basicity of the RCOOH reactant on reaction energetics. These calculations, together with prior experimental and theoretical studies of the acetic and trifluoroacetic derivatives, demonstrate that the basicity of the carbonyl oxygen, not the acidity of the COOH proton, is the important driving factor for the reaction. As a precursor to the experimental work on the title molecule, microwave spectra of the parent and OD forms of the pivalic acid monomer were recorded and are reported here as well. A convenient synthesis of SO3 is also described.

Telehealth provider experience in reproductive endocrinology and infertility clinics during the COVID-19 pandemic and beyond.

PURPOSE: To assess telehealth services offered by reproductive endocrinology and infertility specialists and to gauge provider experiences with incorporating telehealth into their practices. METHODS: A 16-question web-based survey on use of telehealth was distributed to Society for Assisted Reproductive Technology (SART) clinics and to Society for Reproductive Endocrinology and Infertility (SREI) members. Clinic demographic data, telehealth descriptive data, and provider satisfaction with use of telehealth were assessed. Results were collected via Survey Monkey. RESULTS: A total of 1160 individuals (330 SART clinic contacts and 830 SREI members) were reached via email with an 18.6% (216) survey response rate. All respondents indicated that they offer telehealth visits. Several telehealth platforms were used, with Zoom (62.7%) and telehealth through the clinic's electronic medical record platform (34.8%) being the most common. The majority of participants (87.0%) anticipate they will offer telehealth visits after the COVID-19 pandemic. Roughly two-thirds (64.4%) of respondents anticipate fewer telehealth visits after the pandemic because of logistics, cost, and patient/provider preference. Nearly all providers are either "very satisfied" (66.2%) or "somewhat satisfied" (31.0%) with telehealth overall. CONCLUSION: Telehealth enabled safe patient-provider interactions throughout the COVID-19 pandemic. While only one-third of survey respondents offered telehealth services before the pandemic, nearly all providers express satisfaction with telehealth and anticipate they will offer telehealth services henceforth.

Gender bias in the medical education of obstetrician-gynaecologists in the United States: A systematic review.

BACKGROUND: The number of men entering obstetrics and gynaecology (Ob/Gyn) residencies and general Ob/Gyn practice is decreasing. Gender biases against their participation may affect career decisions. OBJECTIVE: This systematic review examines: (i) female patients' gender preferences and perceptions of men as Ob/Gyns and/or medical students; and (ii) the influence of gender on students' education and career decisions. SEARCH STRATEGY: We identified relevant research via PubMed using variations of three concepts in combination: Ob/Gyn care, gender bias/preference, and medical education or career. We conducted the initial review in 2018 and repeated the search in March 2021, adding additional references via citation review of included research. SELECTION CRITERIA: We restricted the review to original research from the United States between 2000-2021. DATA COLLECTION: Fifteen studies met inclusion criteria, categorised into three groups: (i) patient's gender preference for Ob/Gyns; (ii) patient's gender preference for medical students during the Ob/Gyn clerkship; and (iii) influence of gender bias on Ob/Gyn career decisions. MAIN RESULTS: Patients prioritised their physician's care attributes (eg technical skill, compassion, experience) over gender when choosing Ob/Gyns; however, provider gender was prioritised for medical students. Male medical students more commonly reported exclusion from clinical opportunities, although objective clinical exposure was like that of female counterparts. Despite perceived gender bias, male medical students reported increased Ob/Gyn interest post-clerkship; interest did not translate into residency applications. These findings are limited by study quality and heterogeneity. CONCLUSIONS: Real and perceived gender bias among female patients and male medical students in Ob/Gyn may underlie declining numbers of men entering the field.

Beyond single crystals: Imaging rubrene polymorphism across crystalline batches through lattice phonon Raman microscopy.

Polymorphism is an issue troubling numerous scientific fields. A phenomenon where molecules can arrange in different orientations in a crystal lattice, polymorphism in the field of organic photovoltaic materials can dramatically change electronic properties of these materials. Rubrene is a benchmark photovoltaic material showing high carrier mobility in only one of its three polymorphs. To use rubrene in devices, it is important to quantify the polymorph distribution arising from a particular crystal growth method. However, current methods for characterizing polymorphism are either destructive or inefficient for batch scale characterization. Lattice phonon Raman spectroscopy has the ability to distinguish between polymorphs based on low frequency intermolecular vibrations. We present here the addition of microscopy to lattice phonon Raman spectroscopy, which allows us to not only characterize polymorphs efficiently and nondestructively through Raman spectroscopy but also concurrently gain information on the size and morphology of the polymorphs. We provide examples for how this technique can be used to perform large, batch scale polymorph characterization for crystals grown from solution and physical vapor transport. We end with a case study showing how Raman microscopy can be used to efficiently optimize a green crystal growth method, selecting for large orthorhombic crystals desired for rubrene electronic device applications.

Studies towards the total synthesis of drimentine C. Preparation of the AB and CDEF ring fragments.

The drimentine family is a class of hybrid isoprenoids derived from actinomycete bacteria. Members of this family display weak antitumor and antibacterial activity. Herein we report our efforts toward the total synthesis of drimentine C using three distinct approaches incorporating palladium-catalyzed cyanoamidation, reductive cross-coupling, and photoredox-catalyzed α-alkylation of an aldehyde as key steps. Our synthetic efforts use a convergent synthesis to assemble the terpenoid and alkaloid portions of drimentine C from readily available l-tryptophan, l-proline, and (+)-sclareolide.

Sub-mitochondrial localization of the genetic-tagged mitochondrial intermembrane space-bridging components Mic19, Mic60 and Sam50.

Each mitochondrial compartment contains varying protein compositions that underlie a diversity of localized functions. Insights into the localization of mitochondrial intermembrane space-bridging (MIB) components will have an impact on our understanding of mitochondrial architecture, dynamics and function. By using the novel visualizable genetic tags miniSOG and APEX2 in cultured mouse cardiac and human astrocyte cell lines and performing electron tomography, we have mapped at nanoscale resolution three key MIB components, Mic19, Mic60 and Sam50 (also known as CHCHD3, IMMT and SAMM50, respectively), in the environment of structural landmarks such as cristae and crista junctions (CJs). Tagged Mic19 and Mic60 were located at CJs, distributed in a network pattern along the mitochondrial periphery and also enriched inside cristae. We discovered an association of Mic19 with cytochrome c oxidase subunit IV. It was also found that tagged Sam50 is not uniformly distributed in the outer mitochondrial membrane and appears to incompletely overlap with Mic19- or Mic60-positive domains, most notably at the CJs.

Chemoselectivity for Alkene Cleavage by Palladium-Catalyzed Intramolecular Diazo Group Transfer from Azide to Alkene.

Alkenes can be cleaved by means of the (3+2) cycloaddition and subsequent cycloreversion of 1,3-dipoles, classically ozone (O3 ), but the azide (R-N3 ) variant is rare. Chemoselectivity for these azide to alkene diazo group transfers (DGT) is typically disfavored, thus limiting their synthetic utility. Herein, this work discloses a palladium-catalyzed intramolecular azide to alkene DGT, which grants chemoselectivity over competing aziridination. The data support a catalytic cycloreversion mechanism distinct from other known metal-catalyzed azide/alkene reactions: nitrenoid/metalloradical and (3+2) cycloadditions. Kinetics experiments reveal an unusual mechanistic profile in which the catalyst is not operative during the rate-controlling step, rather, it is active during the product-determining step. Catalytic DGT was used to synthesize N-heterocyclic quinazolinones, a medicinally relevant structural core. We also report on the competing aziridination and subsequent ring expansion to another N-heterocyclic core structure of interest, benzodiazepinones.

Palladium and Lewis-Acid-Catalyzed Intramolecular Aminocyanation of Alkenes: Scope, Mechanism, and Stereoselective Alkene Difunctionalizations.

An expansion of methodologies aimed at the formation of versatile organonitriles, via the intramolecular aminocyanation of unactivated alkenes, is herein reported. Importantly, the need for a rigid tether in these reactions has been obviated. The ease-of-synthesis and viability of substrates bearing flexible backbones has permitted for diastereoselective variants as well. We demonstrated the utility of this methodology with the formation of pyrrolidones, piperidinones, isoindolinones, and sultams. Furthermore, subsequent transformation of these motifs into medicinally relevant molecules is also demonstrated. A double crossover 13C-labeling experiment is consistent with a fully intramolecular cyclization mechanism. Deuterium labeling experiments support a mechanism involving syn-addition across the alkene.

Integrating Metal-Catalyzed C-H and C-O Functionalization To Achieve Sterically Controlled Regioselectivity in Arene Acylation.

One major goal of organometallic chemists is the direct functionalization of the bonds most recurrent in organic molecules: C-H, C-C, C-O, and C-N. An even grander challenge is C-C bond formation when both precursors are of this category. Parallel to this is the synthetic goal of achieving reaction selectivity that contrasts with conventional methods. Electrophilic aromatic substitution (EAS) via Friedel-Crafts acylation is the most renowned method for the synthesis of aryl ketones, a common structural motif of many pharmaceuticals, agrochemicals, fragrances, dyes, and other commodity chemicals. However, an EAS synthetic strategy is only effective if the desired site for acylation is in accordance with the electronic-controlled regioselectivity of the reaction. Herein we report steric-controlled regioselective arene acylation with salicylate esters via iridium catalysis to access distinctly substituted benzophenones. Experimental and computational data indicate a unique reaction mechanism that integrates C-O activation and C-H activation with a single iridium catalyst without an exogenous oxidant or base. We disclose an extensive exploration of the synthetic scope of both the arene and the ester components, culminating in the concise synthesis of the potent anticancer agent hydroxyphenstatin.

Synthesis and Characterization of Electron-Deficient Asymmetrically Substituted Diarylindenotetracenes.

Electron-deficient asymmetrically substituted diarylindenotetracenes were prepared via a series of Friedel-Crafts acylations, aryl-aryl cross-couplings, and an intramolecular oxidative cyclization to form the indene ring. Single-crystal X-ray experiments showed good π-π overlap with π-π distances ranging from 3.26 to 3.76 Å. Both thermogravimetric analysis and differential scanning calorimetry indicated that asymmetrically substituted indenotetracenes (ASIs) are stable at elevated temperatures. From cyclic voltammetry experiments, HOMO/LUMO energy levels of ASI derivatives were determined to be near -5.4/-4.0 eV. UV/visible absorption spectra showed strong absorption of light between 400 and 650 nm with molar attenuation coefficients from 104 to 105 M-1 cm-1. ASIs were also found to have very low fluorescence quantum yields, less than 4%. Using the solid-state packing determined from the single-crystal X-ray experiments, computational modeling indicated that ASI molecules should favor electron transport.

Five Fatty Aldehyde Dehydrogenase Enzymes from Marinobacter and Acinetobacter spp. and Structural Insights into the Aldehyde Binding Pocket.

Enzymes involved in lipid biosynthesis and metabolism play an important role in energy conversion and storage and in the function of structural components such as cell membranes. The fatty aldehyde dehydrogenase (FAldDH) plays a central function in the metabolism of lipid intermediates, oxidizing fatty aldehydes to the corresponding fatty acid and competing with pathways that would further reduce the fatty aldehydes to fatty alcohols or require the fatty aldehydes to produce alkanes. In this report, the genes for four putative FAldDH enzymes from Marinobacter aquaeolei VT8 and an additional enzyme from Acinetobacter baylyi were heterologously expressed in Escherichia coli and shown to display FAldDH activity. Five enzymes (Maqu_0438, Maqu_3316, Maqu_3410, Maqu_3572, and the enzyme reported under RefSeq accession no. WP_004927398) were found to act on aldehydes ranging from acetaldehyde to hexadecanal and also acted on the unsaturated long-chain palmitoleyl and oleyl aldehydes. A comparison of the specificities of these enzymes with various aldehydes is presented. Crystallization trials yielded diffraction-quality crystals of one particular FAldDH (Maqu_3316) from M. aquaeolei VT8. Crystals were independently treated with both the NAD+ cofactor and the aldehyde substrate decanal, revealing specific details of the likely substrate binding pocket for this class of enzymes. A likely model for how catalysis by the enzyme is accomplished is also provided.IMPORTANCE This study provides a comparison of multiple enzymes with the ability to oxidize fatty aldehydes to fatty acids and provides a likely picture of how the fatty aldehyde and NAD+ are bound to the enzyme to facilitate catalysis. Based on the information obtained from this structural analysis and comparisons of specificities for the five enzymes that were characterized, correlations to the potential roles played by specific residues within the structure may be drawn.

Topical administration of a Rock/Net inhibitor promotes retinal ganglion cell survival and axon regeneration after optic nerve injury.

Intraocular pressure (IOP)-lowering ophthalmic solutions that inhibit Rho-associated protein kinases (Rock) and norepinephrine transporters (Net) are currently under clinical evaluation. Here we evaluate topical application of one such drug for its effects on retinal ganglion cell (RGC) survival and axon regeneration after optic nerve crush injury. We performed unilateral optic nerve crush on young rats (P18) and topically applied Rock/Net inhibitor AR-13324 or placebo 3 times a day for 14 days. IOP was measured starting 3 days before and up to 9 days after injury. On day 12, cholera toxin B (CTB) was injected intravitreally to trace optic nerve regeneration. On day 14, retinas and optic nerves were collected. The retinas were flat-mounted and stained with RBPMS to quantify RGC survival and the optic nerves were sectioned for optic nerve axon quantification using fluorescent and confocal microscopy. Rock phosphorylation targets implicated in axon growth including cofilin and LIMK were examined by fluorescence microscopy and quantitative western blotting. AR-13324 lowered IOP as expected. RGC survival and optic nerve axon regeneration were significantly higher with Rock/Net inhibitor treatment compared with placebo. Furthermore, topical therapy decreased Rock target protein phosphorylation in the retinas and proximal optic nerves. These data suggest that topical administration of a Rock/Net inhibitor promotes RGC survival and regeneration after optic nerve injury, with associated molecular changes indicative of posterior drug activity. Coordinated IOP lowering and neuroprotective or regenerative effects may be advantageous in the treatment of patients with glaucoma.

Mechanistic Model for Enantioselective Intramolecular Alkene Cyanoamidation via Palladium-Catalyzed C-CN Bond Activation.

We studied key aspects of the mechanism of Pd-catalyzed C-CN bond activation and intramolecular enantioselective alkene cyanoamidation. An Abboud-Abraham-Kamlet-Taft (AAKT) linear solvation energy relationship (LSER) model for enantioselectivity was established. We investigated the impact of Lewis acid (BPh3), Lewis base (DMPU), and no additives. BPh3 additive led to diminished enantioselectivity and differing results in 13CN crossover experiments, initial rate kinetics, and natural abundance 12C/13C kinetic isotope effect measurements. We propose two catalytic mechanisms to account for our experimental results. We propose that the DMPU/nonadditive pathway passes through a κ2-phosphoramidite-stabilized Pd+ intermediate, resulting in high enantioselectivity. BPh3 prevents the dissociation of CN-, leading to a less rigid κ2-phosphoramidite-neutral Pd intermediate.

Development and Mechanistic Study of Quinoline-Directed Acyl C-O Bond Activation and Alkene Oxyacylation Reactions.

The intramolecular addition of both an alkoxy and acyl substituent across an alkene, oxyacylation of alkenes, using rhodium catalyzed C-O bond activation of an 8-quinolinyl ester is described. Our unsuccessful attempts at intramolecular carboacylation of ketones via C-C bond activation ultimately informed our choice to pursue and develop the intramolecular oxyacylation of alkenes via quinoline-directed C-O bond activation. We provide a full account of our catalyst discovery, substrate scope, and mechanistic experiments for quinoline-directed alkene oxyacylation.

Diastereoselective Intramolecular Cyanoamidation with Alkenes.

Reported herein is a diastereoselective intramolecular alkene cyanoamidation, wherein high d.r. values are imparted by chiral directing groups. Lactams with an α-all-carbon quaternary stereocenter are readily synthesized, which may enable access to structures frequently found in biologically active molecules and natural products.

Food portion size area mediates energy effects on expected anxiety in anorexia nervosa.

A study in which adolescent patients with anorexia nervosa (n = 24) rated their expected food-anxiety in response to images of portions of food (potatoes, rice pizza, and M&Ms) showed that lower energy-dense foods elicited higher expected anxiety per kilocalorie than higher energy-dense foods. However, the area of the portion sizes could be an unmeasured variable driving the anxiety response. To test the hypothesis that area mediates the effects of energy content on expected anxiety, the same images of portions were measured in area (cm2), and standardized values of expected anxiety were regressed from standardized values of energy and area of portions. With regression of expected anxiety from portion size in area, M&Ms, which had the highest energy density of the four foods, elicited the highest expected anxiety slope (ß = 1.75), which was significantly different from the expected anxiety slopes of the other three foods (ß range = 0.67 - 0.96). Area was confirmed as a mediator of energy effects from loss of significance of the slopes when area was added to the regression of expected anxiety from energy x food. When expected anxiety was regressed from food, area, energy and area by energy interaction, area accounted for 5.7 times more variance than energy, and ß for area (0.7) was significantly larger (by 0.52, SE = 0.15, t = 3.4, p = 0.0007) than ß for energy (0.19). Area could be a learned cue for the energy content of food portions, and thus, for weight gain potential, which triggers anxiety in patients with anorexia nervosa.

Materials in the vitreous during cataract surgery: nature and incidence, with two cases of histological confirmation.

BACKGROUND: To identify and classify materials in the vitreous observed during phacoemulsification cataract surgery (phaco). DESIGN: Prospective, consecutive, observational case series at one ophthalmic day surgery in Sydney, Australia. PARTICIPANTS: A total of 767 consecutive phaco cases. Cases were excluded if there was posterior capsule rupture or vitreous loss intraoperatively. METHODS: For each patient, age, gender, baseline corrected distance visual acuity, presence of pseudoexfoliation, nuclear sclerosis grade and phacoemulsification ultrasound time were recorded. The relationship between these variables and materials in the vitreous was evaluated with regression analysis. Two patients with materials in the vitreous developed an acute intraoperative rock-hard eye syndrome. In these two patients, pars plana needle aspiration of retrolenticular fluid was performed to re-establish normal intraocular pressure. Histology was undertaken to compare this fluid with known lens material retrieved from the Fluid Management System bags in two unrelated cases. MAIN OUTCOME MEASUREMENTS: Presence of materials in the vitreous during phaco. RESULTS: Materials in the vitreous were observed in either Berger's space or the anterior vitreous in 386 eyes (50.3% of cases); the majority was putatively lens material (46.5% of all cases). Pigment and ophthalmic viscoelastic device were seen in the anterior vitreous in 9.8% and 1.7% of cases, respectively. Logistic regression analysis demonstrated that higher nuclear sclerosis grade (P = 0.025), male gender (P = 0.003) and greater age (P = 0.016) were predictive of the presence of materials in the vitreous. Histological assessment with light microscopy and birefringence techniques identified the materials in the vitreous as lens material. CONCLUSION: Materials in the vitreous were seen in 50.3% of phaco cases. It has been histologically demonstrated that lens materials can be introduced into the anterior vitreous during phaco.

Cardiac rehabilitation in African Americans: evidence for poorer outcomes compared with whites, especially in women and diabetic participants.

BACKGROUND: Cardiac rehabilitation (CR) improves coronary artery disease risk factors and mortality. Outcomes after CR in African Americans (AAs) compared with whites have not been studied extensively. METHODS: A total of 1,096 patients (169 AAs, 927 whites) were enrolled in a 36-session CR program for ischemic heart disease or postcardiac surgery. The program consisted of exercise, lifestyle modification, and pharmacotherapy. RESULTS: After CR, quality of life, blood pressure, and low-density lipoprotein cholesterol improved significantly in both AAs and whites, although to a lesser degree in AAs. Whites also had significant improvements in weight and triglyceride concentrations. Overall, mean peak exercise capacity, measured in metabolic equivalents (METs), improved by only 1.6 (95% CI 1.3-1.8) in AAs compared with 2.4 (2.3-2.6) in CCs (P< .001 for AAs vs CCs). African American women had the least improvement in METs, but changes were still significant (1.1 [CI 0.9-1.4]). The subgroup with the least improvement in METs was AA diabetic patients (1.4 (CI 1.1-1.7]). CONCLUSION: African Americans derive a significant benefit from CR, but not to the same degree as whites, based on changes in risk factors and in exercise capacity. Within both ethnic groups, both women and diabetic patients appeared to have markedly less improvement.