Anatomy of a liquidity crisis: Corporate bonds in the COVID-19 crisis.

We examine the microstructure of liquidity provision in the COVID-19 corporate bond liquidity crisis. During the two weeks leading up to Federal Reserve System interventions, volume shifted to liquid securities, transaction costs soared, trade-size pricing inverted, and dealers, particularly non-primary dealers, shifted from buying to selling, causing dealers' inventories to plummet. Liquidity provisions in electronic customer-to-customer trading increased, though at prohibitively high costs. By improving dealer funding conditions and providing a liquidity backstop, the Primary Dealer Credit Facility and the Secondary Market Corporate Credit Facility (SMCCF) stabilized trading conditions. Most of the impact of SMCCF on bond liquidity seems to have materialized following its announcement. We argue that the Federal Reserve's actions reflect a new role as market maker of last resort.

Assessment of the FilmArray® multiplex PCR system and associated meningitis/encephalitis panel in the diagnostic service of a tertiary hospital.

Rapid and accurate diagnosis of meningitis/encephalitis (M/E) is essential for successful patient outcomes. The FilmArray® meningitis/encephalitis Panel (MEP) is a multiplexed PCR test for simultaneous, rapid detection of pathogens directly from cerebrospinal fluid (CSF) samples. 94 prospectively collected CSF specimens from patients with clinical suspicion of infective M/E underwent testing for 14 pathogens simultaneously, including Escherichia coli, Haemophilus influenzae, Neisseria meningitidis, and Varicella zoster. MEP demonstrated 95% agreement with current PCR methods, resulting in 16 diagnosed cases of M/E. Typically, the FilmArray® MEP results were delivered within approximately one hour, contrasting with current practices taking up to 5.6 days. Given the significant morbidity and mortality associated with delayed diagnosis of central nervous system infections, the FilmArray® MEP is a useful addition to the diagnostic capabilities of a clinical microbiology department.

Rising to the occasion: New persons for new times / Respondendo aos desafios contemporâneos: novas pessoas para novos tempos

Global problems are accelerating to the point where they are challenging civilization. The author reflects on how early mentors in Biological and Psychological science modeled a new paradigm for their inquiry that included subject-subject participation, qualitative methods, a wider range of accepted evidence and the ability to indwell in a state of "not knowing" and letting coherence emerge. Such an approach not only leads to new knowledge but also develops capacities and competencies in the researcher that are more adequate for understanding complex and seemingly intractable crises of global the 21st century. The author identifies three levels of crisis occurring simultaneously: conceptual, cultural and existential which undermine coherence at personal and societal levels. When societies destabilize doubt and uncertainty rise producing the possible responses of defensiveness, anarchy and transformation. To optimize the possibility of transformation a new kind of psychology is needed that is better adapted to current conditions. Persons of Tomorrow, a term coined by humanistic psychologist Carl Rogers during the upheavals of the 1960s, have the consciousness and capacities to address these crises in creative and transformative ways. The non-profit International Futures Forum has developed theory, pedagogy and social practices to facilitate transformative innovation. Case examples of its and others' transformative projects are described and linked to the urgent need to develop and to practice as Persons of Tomorrow.

Os problemas globais estão aumentando a tal ponto que ameaçam a civilização humana. A autora reflete sobre como seus mentores das áreas de Biologia e Psicologia desenvolveram um novo paradigma em suas pesquisas que se caracteriza por contemplar uma relação sujeito-sujeito entre o pesquisador e o participante da pesquisa, métodos qualitativos, uma gama mais ampla de evidências comprovadas e a habilidade para colocar-se numa posição de "não saber' de forma a permitir que a coerência sobre algo possa surgir naturalmente. Tal abordagem, não apenas leva a novos conhecimentos, como também desenvolve capacidades e competências no pesquisador que são mais adequadas para compreender as complexas e aparentemente insolúveis crises do século 21. A autora identifica três níveis de crises ocorrendo de maneira simultânea - conceitual, cultural e existencial - e que tendem a solapar a coerência nos níveis pessoal e social. Quando as sociedades se desestabilizam dúvidas e incertezas aparecem produzindo reações de defesa, anarquia e transformação. Para otimizar a possibilidade de transformação, faz-se necessário um novo tipo de Psicologia, mais adaptado às condições atuais. Pessoas do Amanhã, um termo cunhado pelo psicólogo humanista Carl R. Rogers durante os conflitos da década de sessenta do século XX, possuem a consciência e as capacidades para enfrentar estas crises de modo criativo e transformador. A Futures-Forum, uma organização sem fins lucrativos, desenvolve teorias, estratégias pedagógicas e práticas sociais visando facilitar inovações transformadoras Exemplos deste e de outros projetos transformadores são descritos e também associados a urgente necessidade do desenvolvimento de uma prática no estilo das Pessoas do Amanhã.

From High Touch to High Tech: A Conversation With Maureen O'Hara, BSN, RN, OCN.

An oncology nurse talks about her 42-year career at Stanford Medical Center. The technological and pharmacological advances she has seen in that time have changed the face of oncology nursing practice and transformed many previously fatal cancers into curable diseases or chronic illnesses compatible with well-being. The increasing complexity of care requires multidisciplinary collaboration and brings with it new ethical dilemmas. She cautions nurses to make the best use of technology without losing their critical thinking skills, basic assessment skills, and common sense.

Mutational analysis of the herpes simplex virus type 1 UL25 DNA packaging protein reveals regions that are important after the viral DNA has been packaged.

The herpes simplex virus type 1 (HSV-1) UL25 gene encodes a minor capsid protein, pUL25, that is essential for packaging the full-length viral genome. Six regions which contain disordered residues have been identified in the high-resolution structure of pUL25. To investigate the significance of these flexible regions, a panel of plasmids was generated encoding mutant proteins, with each member lacking the disordered residues in one of the six regions. In addition, UL25 constructs were produced, which specified proteins that contained missense mutations individually affecting two of the four regions on the surface of pUL25 predicted from evolutionary trace analysis to be important in protein-protein interactions. The impacts of these mutations on viral DNA packaging, virus assembly, and growth were examined. Of the nine mutant proteins analyzed, five failed to complement the growth of a UL25 deletion mutant in Vero cells. These noncomplementing proteins fell into three classes. Proteins in one class did not alter the DNA packaging phenotype of an HSV-1 UL25 deletion mutant, whereas proteins from the other two classes allowed the UL25 null mutant to package full-length viral DNA. Subsequent analysis of the latter classes of mutant proteins demonstrated that one class enabled the null virus to release enveloped virus particles from U2OS cells, whereas the other class prevented egress of mature HSV-1 capsids from the nucleus. These findings reveal a new role for pUL25 in virion assembly, consistent with its flexible structure and location on the capsid.

Modulation of human arterial tone during pregnancy: the effect of the bioactive metabolite sphingosine-1-phosphate.

Sphingosine-1-phosphate (S1P) is a potent bioactive lipid that has been implicated in cardiovascular disease. The objective of the present study was to determine the vasoactive effects and underlying mechanisms of S1P on adult human maternal arteries. The isometric tensions of the omental and myometrial arteries isolated from normal pregnant women at term were assessed in response to incremental doses of S1P in the presence or absence of the nitric oxide (NO) synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME). The putative involvement of Rho-associated kinases (ROCKs) in intact arteries and in those permeabilized with alpha-toxin, to study agonist-dependent calcium-sensitization, was assessed with the inhibitor Y27632. Real-time RT-PCR established the presence of mRNA encoding the S1P receptors (S1P(1) to (3)), previously known as endothelial differentiation gene receptors (EDG1, 3 and 5), in both artery types. S1P induced a dose-dependent increase in the isometric tension of all the arteries. Y27632 reduced constriction due to S1P in intact arteries and reduced S1P-induced sensitization of contraction to submaximal activating Ca(2+) in permeabilized arteries. L-NAME also modulated S1P vasoactive responses in a tissue-specific manner. Two subgroups of omental arteries were identified, one of which utilizes the NO pathway. In myometrial arteries, S1P evoked oscillatory constrictions, whereas pretreatment with L-NAME resulted in only tonic constrictions of unaltered peak magnitude. The prominent vasoactive actions of S1P in the maternal arteries of pregnant women are modulated by inhibitors of ROCKs and NO bioavailability. The subtle tissue-specific functional differences in the modulation of S1P actions by NO have important implications for vascular tone regulation by this bioactive circulatory metabolite during pregnancy.

Phosphodiesterase-5 inhibitors and omental and placental small artery function in normal pregnancy and pre-eclampsia.

OBJECTIVES: In pre-eclampsia (PE), endothelium-dependent function of myometrial small arteries is markedly attenuated. The residual PE response is wholly NO mediated. We have previously demonstrated that PDE5 inhibition can improve endothelial function in myometrial small arteries from women with PE. We aimed to assess whether the effect of PDE5 inhibition in PE was myometrial artery specific. STUDY DESIGN: Small arteries were dissected from omental biopsies obtained at Caesarean section from normal pregnant women (NP, N = 20) and women with PE (N = 11). Chorionic plate small arteries were dissected from NP (N = 13) and PE (N = 11) placentae. Vasoconstriction (arginine vasopressin or thromboxane-mimetic U46619) and endothelial-dependent relaxation were assessed by wire and pressure myography. Constriction/relaxation curves were repeated post 1h incubation with PDE5 inhibitors UK-343664 or sildenafil citrate (0, 10 or 100 nM). RESULTS: Omental artery constriction was increased in PE. Omental vessel constriction was unaffected by PDE5 inhibition. Sildenafil citrate improved bradykinin-induced but not acetylcholine-induced relaxation of omental small arteries from NP women. PDE5 inhibition did not alter relaxation of omental arteries from women with PE. Placental small arteries were unaffected by PDE5 inhibition. CONCLUSION: Use of PDE5 inhibitors does not significantly alter endothelial-dependent relaxation in omental or placental small arteries from PE women.

Sphingosine-1-phosphate acts via rho-associated kinase and nitric oxide to regulate human placental vascular tone.

Sphingosine-1-phosphate (S1P), a bioactive lipid released from activated platelets, has been demonstrated in animal models to regulate vascular tone through receptor-mediated activation of Rho-associated kinase 1 and nitric oxide synthase 3. The role of S1P in regulation of human vascular tone (particularly during pregnancy, with its unique vascular adaptations and localized platelet activation) is unknown. We hypothesized that S1P would constrict small placental arteries through activation of Rho-associated kinases with modulation by nitric oxide. Reverse transcription-polymerase chain reaction of chorionic plate artery preparations detected mRNAs encoding all five receptors for S1P, and S1P induced dose-dependent vasoconstriction of both chorionic plate and stem villous isobarically mounted arteries, which at 10 micromol/L was 32.9% +/- 3.86% (mean +/- SEM) and 34.6% +/- 7.01%, respectively. In stem villous arteries, S1P-induced vasoconstriction was enhanced significantly following inhibition of nitric oxide synthases with N(G)-nitro-L-arginine methyl ester (100 micromol/L, 52.6% +/- 6.28%, P < 0.05). The S1P-induced vasoconstriction was reversed by Y27632, an inhibitor of Rho-associated kinases (10 micromol/L) in both chorionic plate (to 14.9% +/- 4.95%) and stem villous arteries (to 2.71% +/- 6.13%). The S1P added to alpha-toxin-permeabilized, isometrically mounted chorionic plate arteries bathed in submaximal Ca(2+)-activating solution induced Ca(2+)-sensitization of constriction, which was 47.7% +/- 10.0% of that occurring to maximal Ca(2+)-activating solution. This was reduced by Y27632 to 18.4% +/- 18.4%. Interestingly, S1P-induced vasoconstriction occurred in all isobarically mounted arteries but was inconsistent in isometrically mounted chorionic plate arteries. In summary, S1P-induced vasoconstriction in human placental arteries is mediated by increased Ca(2+)-sensitization through activation of Rho-associated kinases, and this vasoconstriction also is modulated by nitric oxide. Identification of these actions of S1P in the placental vasculature is important for understanding both normal and potentially abnormal vascular adaptations with pregnancy.

The involvement of Rho-associated kinases in agonist-dependent contractions of human maternal and placental arteries at term gestation.

OBJECTIVE: The purpose of this study was to assess the involvement of rho kinase (ROK) in agonist-dependent contraction of omental, myometrial, and placental arteries of pregnant women at term. STUDY DESIGN: Wire myography was used to assess if contractions of intact or alpha-toxin-permeabilized arteries obtained from women at elective cesarean section were influenced by the ROK inhibitor Y-27632. RESULTS: Western blotting indicated the presence of ROKalpha in each of the 3 tissue types. In intact human omental, myometrial, or placental arteries, Y-27632 dose-dependently reduced constrictions to the thromboxane-mimetic U46619. In permeabilized vessels, U46619 induced substantial Ca(2+)-sensitization of contraction that was inhibited by Y27632. The phosphatase inhibitor calyculin A induced a Ca(2+)sensitization of contraction similar to that of U46619 in permeabilized omental arteries that was unaffected by Y-27632, suggesting that ROK may signal via myosin phosphatase in these vessels. CONCLUSION: These results are the first report of the involvement of ROK in the receptor-coupled constriction of intact and permeabilized arteries from pregnant women.

Sildenafil citrate (Viagra) enhances vasodilatation in fetal growth restriction.

BACKGROUND: Fetal growth restriction (FGR) affects up to 8% of all pregnancies and has massive short-term (increased fetal morbidity and mortality) and long-term (increased incidence of cardiovascular disease in adulthood) health implications. Doppler waveform analysis of pregnancies complicated by FGR suggests compromised uteroplacental circulation and placental hypoperfusion. Our aim was to determine whether myometrial small artery function was aberrant in FGR and to assess whether sildenafil citrate could improve vasodilatation in FGR pregnancies. METHODS: Small arteries dissected from myometrial biopsies obtained at cesarean section from normal pregnant women (n = 27) or women whose pregnancies were complicated by FGR (n = 12) were mounted on wire myographs. Vessels were constricted (with arginine vasopressin or U46619) and relaxed (with bradykinin) before and after incubation with a phosphodiesterase-5 inhibitor, sildenafil citrate. RESULTS: We demonstrated increased myometrial small artery vasoconstriction and decreased endothelium-dependent vasodilatation in vessels from women whose pregnancies were complicated by FGR. Sildenafil citrate significantly reduced vasoconstriction and significantly improved relaxation of FGR small arteries. CONCLUSIONS: We conclude that sildenafil citrate improves endothelial function of myometrial vessels from women whose pregnancies are complicated by intrauterine growth restriction. Sildenafil citrate may offer a potential therapeutic strategy to improve uteroplacental blood flow in FGR pregnancies.

Effects of a phosphodiesterase-5 (PDE5) inhibitor on endothelium-dependent relaxation of myometrial small arteries.

OBJECTIVE: In preeclampsia, endothelium-dependent function is markedly aberrant. Myometrial resistance arteries from women with preeclampsia show a minimal, wholly nitric oxide-mediated, bradykinin-induced relaxation. Our aim was to test that phosphodiesterase 5 (PDE5) inhibition could improve endothelium-dependent function in preeclampsia. Study design Small arteries dissected from myometrial biopsies obtained at cesarean section from normal pregnant women (N=22) or women with preeclampsia (N=24) were mounted on wire or pressure myographs. Vessels were constricted (arginine vasopressin or U46619) and relaxed (bradykinin) before and after incubation with a PDE5 inhibitor, UK-343664. RESULTS: Endothelium-dependent vasodilatation was decreased in vessels from women with preeclampsia. 100 nmol/L UK-343664 did not affect normal pregnant but significantly improved relaxation of the vessels from women with preeclampsia. CONCLUSION: A PDE5 inhibitor enhances endothelial function of myometrial vessels from women with preeclampsia, such that the behavior of these arteries approximates to those from normal women. These agents offer a potential therapeutic strategy for the management of preeclampsia.

The chemokine receptor D6 constitutively traffics to and from the cell surface to internalize and degrade chemokines.

The D6 heptahelical membrane protein, expressed by lymphatic endothelial cells, is able to bind with high affinity to multiple proinflammatory CC chemokines. However, this binding does not allow D6 to couple to the signaling pathways activated by typical chemokine receptors such as CC-chemokine receptor-5 (CCR5). Here, we show that D6, like CCR5, can rapidly internalize chemokines. However, D6-internalized chemokines are more effectively retained intracellularly because they more readily dissociate from the receptor during vesicle acidification. These chemokines are then degraded while the receptor recycles to the cell surface. Interestingly, D6-mediated chemokine internalization occurs without bringing about a reduction in cell surface D6 levels. This is possible because unlike CCR5, D6 is predominantly localized in recycling endosomes capable of trafficking to and from the cell surface in the absence of ligand. When chemokine is present, it can enter the cells associated with D6 already destined for internalization. By this mechanism, D6 can target chemokines for degradation without the necessity for cell signaling, and without desensitizing the cell to subsequent chemokine exposure.

Purification and biochemical characterization of the D6 chemokine receptor.

There is much interest in chemokine receptors as therapeutic targets in diseases such as AIDS, autoimmune and inflammatory disorders, and cancer. Hampering such studies is the lack of accurate three-dimensional structural models of these molecules. The CC-chemokine receptor D6 is expressed at exceptionally high levels in heterologous transfectants. Here we report the purification and biochemical characterization of milligram quantities of D6 protein from relatively small cultures of transfected mammalian cells. Importantly, purified D6 retains full functional activity, shown by displaceable binding of 125I-labelled MIP-1beta (macrophage inflammatory protein-1beta) and by complete binding of the receptor to a MIP-1alpha affinity column. In addition, we show that D6 is decorated on the N-terminus by N-linked glycosylation. Mutational analysis reveals that this glycosylation is dispensable for ligand binding and high expression in transfected cells. Metabolic labelling has revealed the receptor to also be sulphated and phosphorylated. Phosphorylation is ligand independent and is not enhanced by ligand binding and internalization, suggesting similarities with the viral chemokine receptor homologue US28. Like US28, an analysis of the full cellular complement of D6 in transfected cells indicates that >80% is found associated with intracellular vesicular structures. This may account for the high quantities of D6 that can be synthesized in these cells. These unusual properties of D6, and the biochemical characterization described here, leads the way towards work aimed at generating the three-dimensional structure of this seven-transmembrane-spanning receptor.

Vasoactive effects of neurokinin B on human blood vessels.

OBJECTIVES: Preeclampsia (PE) is a multisystem disease unique to human pregnancy. Abnormal placentation results in placental hypoperfusion leading to the secretion of a factor(s) by the placenta. Our aim was to investigate whether neurokinin B (NKB) is the circulating factor associated with PE. STUDY DESIGN: Vascular effects of NKB were assessed in blood vessels dissected from myometrial and omental biopsy specimens obtained at caesarean section from normal pregnant women (n = 26) or in mesenteric blood vessels obtained from nonpregnant female Wistar rats (n = 4). RESULTS: Incubation with NKB did not alter endothelial-dependent relaxation of omental or myometrial arteries. NKB produced a dose-dependent relaxation in preconstricted omental arteries and veins. NKB did not affect vasoactive responsiveness of rat mesenteric arteries. CONCLUSION: We conclude from these observations that NKB is not the circulating factor associated with increased vascular resistance in PE.