Simulation to improve trainee knowledge and comfort in managing maternal cardiac arrest.

BACKGROUND: Maternal cardiac arrest is a rare outcome, and thus there are limited opportunities for specialists in obstetrics and gynecology to acquire the skills required to respond to it through routine clinical practice. OBJECTIVE: This study aimed to evaluate gaps in medical education in maternal cardiac arrest and whether a simulation-based training program improves resident knowledge and comfort in the diagnosis and treatment of maternal cardiac arrest. STUDY DESIGN: A 2-hour training for obstetrics and gynecology residents at an academic medical center was conducted, consisting of a didactic presentation, defibrillator skills station, and 2 high-fidelity simulations. Consenting residents completed a 21-item pretest followed by a 12-item posttest exploring knowledge of and exposure to maternal cardiac arrest. The McNemar and Wilcoxon signed-rank tests were used to compare pre- and posttest data. RESULTS: Of 21 residents, 15 (71.4%) had no previous education about maternal cardiac arrest, and 17 (81.0%) had never responded to a maternal code. Participants demonstrated increased knowledge about maternal cardiac arrest after the session, providing more correct answers on the reversible causes of pulseless electrical activity arrest (median 4 vs 7 correct responses; P<.01). After the training, more residents were able to identify the correct gestational age to perform a cesarean delivery during maternal cardiac arrest (19.0% vs 90.5%; P<.01) and the correct location for this procedure (52.4% vs 95.2%; P<.01). All residents reported that maternal cardiac arrest training was important and that they would benefit from additional sessions. Median composite comfort level in managing maternal cardiac arrest significantly increased after participation (pretest, 24.0 [interquartile range, 21.5-28.0]; posttest, 37.0 [interquartile range, 34.3-41.3]; P<.01). CONCLUSION: Residents report limited exposure to maternal cardiac arrest and desire more training. Simulation-based training about maternal cardiac arrest is needed during residency to ensure that graduates are prepared to respond to this high-acuity event.

The Mutability of Yeast Prions.

Prions replicate by a self-templating mechanism. Infidelity in the process can lead to the emergence of new infectious structures, referred to as variants or strains. The question of whether prions are prone to mis-templating is not completely answered. Our previous experiments with 23 variants of the yeast [PSI+] prion do not support broad mutability. However, it became clear recently that the heat shock protein Hsp104 can restrict [PSI+] strain variation. This raises the possibility that many transmutable variants of the prion may have been mistaken as faithful-propagating simply because the mutant structure was too sturdy or too frail to take root in the wild-type cell. Here, I alter the strength of Hsp104 in yeast, overexpressing wild-type Hsp104 or expressing the hypo-active Hsp104T160M mutant, and check if the new environments enable the variants to mutate. Two variants hitherto thought of as faithful-propagating are discovered to generate different structures, which are stabilized with the hypo-active chaperone. In contrast, most transmutable variants discovered in cells overexpressing Hsp104 have been correctly identified as such previously in wild-type cells without the overexpression. The majority of transmutable variants only mis-template the structure of VH, VK, or VL, which are the most frequently observed variants and do not spontaneously mutate. There are four additional variants that never give rise to different structures in all cell conditions tested. Therefore, quite a few [PSI+] variants are faithful-propagating, and even the transmutable ones do not freely evolve but can only change to limited structural types.

Patient characteristics associated with SARS-CoV-2 infection in parturients admitted for labour and delivery in Massachusetts during the spring 2020 surge: A prospective cohort study.

BACKGROUND: While studies from large cities affected by coronavirus disease 2019 (COVID-19) have reported on the prevalence of SARS-CoV-2 in the context of universal testing during admission for delivery, the patient demographic, social and clinical factors associated with SARS-CoV-2 infection in pregnant women are not fully understood. OBJECTIVE: To evaluate the epidemiological factors associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in women admitted for labour and delivery, in the context of universal screening at four Boston-area hospitals. METHODS: In this prospective cohort study, we reviewed the health records of all women admitted for labour and delivery at four hospitals from the largest health system in Massachusetts between 19 April 2020 and 27 June 2020. We calculated the risk of SARS-CoV-2 infection, including asymptomatic infection. We calculated associations between SARS-CoV-2 infection and demographic and clinical characteristics. RESULTS: A total of 93 patients (3.2%, 95% confidence interval 2.5, 3.8) tested positive for SARS-CoV-2 infection on admission for labour and delivery out of 2945 patients included in the analysis; 80 (86.0%) of the patients who tested positive were asymptomatic at the time of testing. Factors associated with SARS-CoV-2 infection included the following: younger age, obesity, African American or Hispanic race/ethnicity, residence in heavily affected communities (as measured in cases reported per capita), presence of a household member with known SARS-CoV-2 infection, non-health care essential worker occupation and MassHealth or Medicaid insurance compared to commercial insurance. 93.8% of patients testing positive for SARS-CoV-2 on admission had one or more identifiable factors associated with disease acquisition. CONCLUSIONS: In this large sample of deliveries during the height of the surge in infections during the spring of 2020, SARS-CoV-2 infection was largely concentrated in patients with distinct demographic characteristics, those largely from disadvantaged communities. Racial disparities seen in pregnancy persist with respect to SARS-CoV-2 infection.

Mutable yeast prion variants are stabilized by a defective Hsp104 chaperone.

Gorkovskiy et al. observed that many [PSI+ ] prion isolates, obtained in yeast with the mutant Hsp104T160M chaperone, propagate poorly in wild-type cells and suggested that Hsp104 is part of the cellular anti-prion system, curing many nascent [PSI+ ] variants. Here, we argue that the concept may require reassessment. We induced [PSI+ ] variants in both the wild-type and the mutant background. Three new variants were isolated in the T160M background. They exhibited lower thermostability, possessed novel structural features, and were inherently mutable, changing to well-characterized VH, VK, and VL variants in wild-type cells. In contrast, VH, VK, and VL of the wild-type background, could not change freely and were lost in the mutant, due to insufficient chaperone activity. Thus, mutant Hsp104 can impose as much restriction against emerging prion variants as the wild-type protein. Such restriction conserved the transmutable variants in the T160M background, since new structures mis-templated from them could not gain a foothold. We further demonstrate excess Hsp104T160M or Hsp104∆2-147 can eliminate nearly all of the [PSI+ ] variants in their native background. This finding contradicts the generally held belief that Hsp104-induced [PSI+ ] curing requires its N-terminal domain, and may help settling the current contention regarding how excess Hsp104 cures [PSI+ ].

A complete catalog of wild-type Sup35 prion variants and their protein-only propagation.

Twenty-three prion variants of the wild-type Sup35 protein are obtained, including 19 novel ones and 4 previously documented, namely, VH, VK, VL, and W8. Their uniqueness and non-composite nature are demonstrated. Specific infectivity is generated de novo for most variants by adding prion particles to solutions of a purified Sup35 N-terminal fragment, thereby supporting the protein-only composition. Sup35 prions isolated by other laboratories are identified within the collection and found to fall into a narrow set of five variant types that are readily inducible in vivo by Sup35 overexpression. The work establishes an unambiguous and extensive collection of prion variants, demonstrating that a protein, by itself, in the absence of genetic and conformational co-factors, could adopt a great number of structures. In light of recent high-resolution structures of other amyloids, we discuss how the diverse folding is achieved in spite of apparent contradiction to the classical paradigm that a protein's structure is uniquely determined by its sequence.

BDNF elevates the axonal levels of hnRNPs Q and R in cultured rat cortical neurons.

Local translation plays important roles in the maintenance and various functions of axons, and dysfunctions of local translation in axons are implicated in various neurological diseases. Heterogeneous nuclear ribonucleoproteins (hnRNPs) are RNA binding proteins with multiple functions in RNA metabolism. Here, we identified 20 hnRNPs in the axons of cultured rat cortical neurons by interrogating published axon mass spectrometric databases with rat protein databases. Among those identified in axons are highly related hnRNPs Q and R. RT-PCR analysis indicated that axons also contained low levels of hnRNPs Q and R mRNAs. We further found that BDNF treatments raised the levels of hnRNPs Q and R proteins in whole neurons and axons. BDNF also increased the level of poly(A) RNA as well as the proportion of poly(A) RNA granules containing hnRNPs Q and R in the axon. However, following severing the connection between the cell bodies and axons, BDNF did not affect the levels of hnRNPs Q and R, the content of poly(A) RNA, or the colocalization of poly(A) RNA and hnRNPs Q and R in the axon any more, although BDNF still stimulated the local translation in severed axons as it did in intact axons. The results are consistent with that BDNF enhances the axonal transport of RNA granules. The results further suggest that hnRNPs Q and R play a role in the mechanism underlying the enhancement of axonal RNA transport by BDNF.

Forms and abundance of chaperone proteins influence yeast prion variant competition.

[PSI+ ] variants are different infectious conformations of the same Sup35 protein. We show that when [PSI+ ] variants VK and VL co-infect a dividing host, only one prevails in the end and the host genetic background is involved in winner selection. In the 5V-H19 background, the VK variant dominates over the VL variant. The order of dominance is reversed in the 74-D694 background, where VL can coexists with VK for a short period, but will eventually take over. Differential interaction of chaperone proteins with distinct prion variant conformations can influence the outcome of competition. Expanding the Glycine/Methionine-rich domain of Sis1, an Hsp40 protein, helps the propagation of VL. Over-expression of the Hsp70 protein Ssa2 lowers the number of prion particles (propagons) in the cell. There is more reduction for VK than VL, causing the latter to dominate in some of the 5V-H19 and all of the 74-D694 cells tested. Consistently, depleting Ssa1 in 74-D694 strengthens VK. Swapping chromosomal alleles of SSA1/2 and SIS1 between 5V-H19 and 74-D694, including cognate promoters, is not sufficient to change the native dominance order of each background, suggesting there exist additional polymorphic factors that modulate [PSI+ ] competition.

Unbiased Proteomic Study of the Axons of Cultured Rat Cortical Neurons.

The axon is a long projection connecting a neuron to its targets. Here, the axons of cultured rat cortical neurons were isolated with micropatterned chips that enable the separation of axons from their cell bodies. Proteins extracted from isolated axons and whole neurons were subjected to analyses using two-dimensional liquid chromatography-tandem mass spectrometry (2D-LC-MS/MS) analyses without and with stable isotope dimethyl labeling, resulting in the identification of >2500 axonal proteins and 103 axon-enriched proteins. A strong correlation exists between the abundances of axonal proteins and their counterparts in whole neurons. The proteomic results confirm the axonal protein constituents of the subcellular structures documented in earlier electron microscopic studies. Cortical axons have proteins that are components of machineries for protein degradation and the synthesis of soluble, membrane, and secretory proteins, although axons lack conventional Golgi apparatus. Despite the fact that axons lack nucleus, nuclear proteins were identified, and 67 of them were found enriched in axons. Some of the results obtained by the MS-based studies were validated by quantitative Western blotting and immunofluorescence staining analyses. The results represent the first comprehensive description of the axonal protein landscape. The MS proteomics data are available via ProteomeXchange with identifier PXD005527.

Understanding the Potential of PARO for Healthy Older Adults.

As the population ages, there is an increasing need for socio-emotional support for older adults. A potential way to meet this need is through interacting with pet-type robots such as the seal robot, PARO. There was a need to extend research on PARO's potential benefits beyond cognitively impaired and dependently living older adults. Because independently living, cognitively intact older adults may also have socio-emotional needs, the primary goal of this study was to investigate their attitudes, emotions, and engagement with PARO to identify its potential applicability to this demographic. Thirty older adults participated in an interaction period with PARO, and their attitudes and emotions toward PARO were assessed before and after using a multi-method approach. Video of the interaction was coded to determine the types and frequency of engagements participants initiated with PARO. Overall, there were no pre-post interaction differences on these measures. However, semi-structured interviews suggested that these older adults had positive attitudes towards PARO's attributes, thought it would be easy to use, and perceived potential uses for both themselves and others. Participants varied in their frequency of engagement with PARO. A novel finding is that this active engagement frequency uniquely predicted post-interaction period positive affect. This study advances understanding of healthy older adults' attitudes, emotions, and engagement with PARO and of possible ways in which PARO could provide social and emotional support to healthy older adults. The results are informative for future research and design of pet-type robots.

Pharmacologic Properties of Novel Local Anesthetic Agents in Anesthesia Practice.

Therapeutic duration of traditional local anesthetics when used in peripheral nerve blocks is normally limited. This article describes novel approaches to extend the duration of peripheral nerve blocks currently available or in development. Three newer approaches on extending the duration of peripheral nerve blocks include site-1 sodium channel blockers, novel local anesthetics delivery systems, and novel adjuvants of local anesthetics. Compared with plain amide-based and ester-based local anesthetics, alternative approaches show significant promise in decreasing postoperative pain, rescue opioid requirement, hospital length-of-stay, and overall health care cost, without compromising the established safety profile of traditional local anesthetics.

Safety of remifentanil in transsphenoidal surgery: A single-center analysis of 540 patients.

Although some studies have examined the efficacy and safety of remifentanil in patients undergoing neurosurgical procedures, none has examined its safety in transsphenoidal operations specifically. In this study, all transsphenoidal operations performed by a single author from 2008 to 2015 were retrospectively reviewed to evaluate the safety of remifentanil in a consecutive series of patients. During the study period, 540 transsphenoidal operations were identified. Of these, 443 (82.0%) patients received remifentanil intra-operatively; 97 (18.0%) did not. The two groups were well-matched with regard to demographic categories, comorbidities, and pre-operative medications (p>0.05), except pre-operative tobacco use (p=0.021). Patients were also well-matched with regard to radiographic features and surgical techniques. Patients who received remifentanil were more likely to harbor a macroadenoma (78.1% vs. 67.0%, p=0.025), and had slightly longer anesthesia time on average (269.2minvs. 239.4min, p=0.024). All pathologic diagnoses were well-matched between the two groups, except that patients receiving remifentanil were more likely to harbor a non-functioning adenoma (46.5% vs. 26.8%, p<0.001). Analysis of post-operative complications showed no significant difference between patients who received remifentanil and those who did not, and length of stay and prevalence of ICU stay did not differ between the two groups. In a well-matched series of 540 patients undergoing transsphenoidal surgery, remifentanil was found to be a safe anesthetic adjunct. There were no significant differences in post-operative hospital course or complications in patients who did and did not receive intra-operative remifentanil.

Amino Acid Proximities in Two Sup35 Prion Strains Revealed by Chemical Cross-linking.

Strains of the yeast prion [PSI] are different folding patterns of the same Sup35 protein, which stacks up periodically to form a prion fiber. Chemical cross-linking is employed here to probe different fiber structures assembled with a mutant Sup35 fragment. The photo-reactive cross-linker, p-benzoyl-l-phenylalanine (pBpa), was biosynthetically incorporated into bacterially prepared recombinant Sup(1-61)-GFP, containing the first 61 residues of Sup35, followed by the green fluorescent protein. Four methionine substitutions and two alanine substitutions were introduced at fixed positions in Sup(1-61) to allow cyanogen bromide cleavage to facilitate subsequent mass spectrometry analysis. Amyloid fibers of pBpa and Met/Ala-substituted Sup(1-61)-GFP were nucleated from purified yeast prion particles of two different strains, namely VK and VL, and shown to faithfully transmit specific strain characteristics to yeast expressing the wild type Sup35 protein. Intra- and intermolecular cross-linking were distinguished by tandem mass spectrometry analysis on fibers seeded from solutions containing equal amounts of (14)N- and (15)N-labeled protein. Fibers propagating the VL strain type exhibited intra- and intermolecular cross-linking between amino acid residues 3 and 28, as well as intra- and intermolecular linking between 32 and 55. Inter- and intramolecular cross-linking between residues 32 and 55 were detected in fibers propagating the VK strain type. Adjacencies of amino acid residues in space revealed by cross-linking were used to constrain possible chain folds of different [PSI] strains.

W8, a new Sup35 prion strain, transmits distinctive information with a conserved assembly scheme.

Prion strains are different self-propagating conformers of the same infectious protein. Three strains of the [PSI] prion, infectious forms of the yeast Sup35 protein, have been previously characterized in our laboratory. Here we report the discovery of a new [PSI] strain, named W8. We demonstrate its robust cellular propagation as well as the protein-only transmission. To reveal strain-specific sequence requirement, mutations that interfered with the propagation of W8 were identified by consecutive substitution of residues 5-55 of Sup35 by proline and insertion of glycine at alternate sites in this segment. Interestingly, propagating W8 with single mutations at residues 5-7 and around residue 43 caused the strain to transmute. In contrast to the assertion that [PSI] existed as a dynamic cloud of sub-structures, no random drift in transmission characteristics was detected in mitotically propagated W8 populations. Electron diffraction and mass-per-length measurements indicate that, similar to the 3 previously characterized strains, W8 fibers are composed of about 1 prion molecule per 4.7-Å cross-ß repeat period. Thus differently folded single Sup35 molecules, not dimeric and trimeric assemblies, form the basic repeating units to build the 4 [PSI] strains.

Kv7.2 regulates the function of peripheral sensory neurons.

The Kv7 (KCNQ) family of voltage-gated K(+) channels regulates cellular excitability. The functional role of Kv7.2 has been hampered by the lack of a viable Kcnq2-null animal model. In this study, we generated homozygous Kcnq2-null sensory neurons using the Cre-Lox system; in these mice, Kv7.2 expression is absent in the peripheral sensory neurons, whereas the expression of other molecular components of nodes (including Kv7.3), paranodes, and juxtaparanodes is not altered. The conditional Kcnq2-null animals exhibit normal motor performance but have increased thermal hyperalgesia and mechanical allodynia. Whole-cell patch recording technique demonstrates that Kcnq2-null sensory neurons have increased excitability and reduced spike frequency adaptation. Taken together, our results suggest that the loss of Kv7.2 activity increases the excitability of primary sensory neurons.

Understanding Older Adults' Perceptions of Usefulness for the Paro Robot.

There is a growing proportion of older adults in the population. Normal aging brings about difficulty in maintaining autonomy as well as an increased need for social support. Animal-assisted therapy and pet-type robots may be a solution to this problem. However, older adults' living situations cannot always accommodate live animals and there are design limitations associated with many of the current pet-type robots. Paro's design addresses some of these issues, but perceptions of Paro's usefulness remain largely unexplored in the normally aging older adult population. The focus of this paper was to address perceived usefulness of the robot Paro as well as potential influencing factors of perceived usefulness. In this study, 30 healthy older adults (ages 67-80) completed questionnaires and answered interview questions regarding perceived usefulness and perceived ease of use of Paro before and after they interacted with it. The data revealed that the participants were neutral regarding perceived usefulness of Paro in their daily lives. However, most participants indicated specific uses for themselves and others, which raised concerns regarding the applicability of the Perceived Usefulness measure in this context. Furthermore, most participants said that they would want to own Paro, and perceived it as being beneficial to other people. Data analysis is ongoing, but initial findings and potential response trends have been identified and discussed. Our results provide insights into healthy older adults' thoughts toward and acceptance of this robot, as well as potential influencing factors of its acceptance.

Dusty: an assistive mobile manipulator that retrieves dropped objects for people with motor impairments.

People with physical disabilities have ranked object retrieval as a high-priority task for assistive robots. We have developed Dusty, a teleoperated mobile manipulator that fetches objects from the floor and delivers them to users at a comfortable height. In this paper, we first demonstrate the robot's high success rate (98.4%) when autonomously grasping 25 objects considered being important by people with amyotrophic lateral sclerosis (ALS). We tested the robot with each object in five different configurations on five types of flooring. We then present the results of an experiment in which 20 people with ALS operated Dusty. Participants teleoperated Dusty to move around an obstacle, pick up an object and deliver the object to themselves. They successfully completed this task in 59 out of 60 trials (3 trials each) with a mean completion time of 61.4 SD = 20.5 seconds), and reported high overall satisfaction using Dusty (7-point Likert scale; 6.8 SD = 0.6). Participants rated Dusty to be significantly easier to use than their own hands, asking family members, and using mechanical reachers (p < 0.03, paired t-tests). Fourteen of the 20 participants reported that they would prefer using Dusty over their current methods. [Box: see text].

Kv7.5 is the primary Kv7 subunit expressed in C-fibers.

Kv7 (KCNQ) potassium channel openers (enhancers) decrease neuropathic pain in experimental models. Here we show that C-fibers, and their associated small-diameter neurons in the dorsal root ganglia (both IB4- and TrkA-positive), expressed Kv7.5. In contrast, C-fibers did not express detectable levels of Kv7.2 or Kv7.3, which are instead localized to nodes of Ranvier and the cell bodies of large sensory neurons. These data suggest that Kv7.5 provides the primary M current in nociceptive neurons.

Inter-allelic prion propagation reveals conformational relationships among a multitude of [PSI] strains.

Immense diversity of prion strains is observed, but its underlying mechanism is less clear. Three [PSI] prion strains--named VH, VK, and VL--were previously isolated in the wild-type yeast genetic background. Here we report the generation and characterization of eight new [PSI] isolates, obtained by propagating the wild-type strains with Sup35 proteins containing single amino-acid alterations. The VH strain splits into two distinct strains when propagated in each of the three genetic backgrounds, harboring respectively single mutations of N21L, R28P, and Gi47 (i.e. insertion of a glycine residue at position 47) on the Sup35 N-terminal prion-forming segment. The six new strains exhibit complex inter-conversion patterns, and one of them continuously mutates into another. However, when they are introduced back into the wild-type background, all 6 strains revert to the VH strain. We obtain two more [PSI] isolates by propagating VK and VL with the Gi47 and N21L backgrounds, respectively. The two isolates do not transmit to other mutant backgrounds but revert to their parental strains in the wild-type background. Our data indicate that a large number of [PSI] strains can be built on three basic Sup35 amyloid structures. It is proposed that the three basic structures differ by chain folding topologies, and sub-strains with the same topology differ in distinct ways by local structural adjustments. This "large number of variations on a small number of basic themes" may also be operative in generating strain diversities in other prion elements. It thus suggests a possible general scheme to classify a multitude of prion strains.