Nature-inspired peptide of MtDef4 C-terminus tail enables protein delivery in mammalian cells

Cell-penetrating peptides show promise as versatile tools for intracellular delivery of therapeutic agents. Various peptides have originated from natural proteins with antimicrobial activity. We investigated the mammalian cell-penetrating properties of a 16-residue peptide with the sequence GRCRGFRRRCFCTTHC from the C-terminus tail of the Medicago truncatula defensin MtDef4. We evaluated the peptide's ability to penetrate multiple cell types. Our results demonstrate that the peptide efficiently penetrates mammalian cells within minutes and at a micromolar concentration. Moreover, upon N-terminal fusion to the fluorescent protein GFP, the peptide efficiently delivers GFP into the cells. Despite its remarkable cellular permeability, the peptide has only a minor effect on cellular viability, making it a promising candidate for developing a cell-penetrating peptide with potential therapeutic applications.

Conversion of methionine biosynthesis in Escherichia coli from trans- to direct-sulfurylation enhances extracellular methionine levels

Methionine is an essential amino acid in mammals and a precursor for vital metabolites required for the survival of all organisms. Consequently, its inclusion is required in diverse applications, such as food, feed, and pharmaceuticals. Although amino acids and other metabolites are commonly produced through microbial fermentation, high-yield biosynthesis of L-methionine remains a significant challenge due to the strict cellular regulation of the biosynthesis pathway. As a result, methionine is produced primarily synthetically, resulting in a racemic mixture of D,L-methionine. This study explores methionine bio-production in E. coli by replacing its native trans-sulfurylation pathway with the more common direct-sulfurylation pathway used by other bacteria. To this end, we generated a methionine auxotroph E. coli strain (MG1655) by simultaneously deleting metA and metB genes and complementing them with metX and metY from different bacteria. Complementation of the genetically modified E. coli with metX/metY from Cyclobacterium marinum or Deinococcus geothermalis, together with the deletion of the global repressor metJ and overexpression of the transporter yjeH, resulted in a substantial increase of up to 126 and 160-fold methionine relative to the wild-type strain, respectively, and accumulation of up to 700 mg/L using minimal MOPS medium and 2 ml culture. Our findings provide a method to study methionine biosynthesis and a chassis for enhancing L-methionine production by fermentation.

A novel computationally engineered collagenase reduces the force required for tooth extraction in an ex-situ porcine jaw model

The currently employed tooth extraction methods in dentistry involve mechanical disruption of the periodontal ligament fibers, leading to inevitable trauma to the bundle bone comprising the socket walls. In our previous work, we have shown that a recombinantly expressed truncated version of clostridial collagenase G (ColG) purified from Escherichia coli efficiently reduced the force needed for tooth extraction in an ex-situ porcine jaw model, when injected into the periodontal ligament. Considering that enhanced thermostability often leads to higher enzymatic activity and to set the basis for additional rounds of optimization, we used a computational protein design approach to generate an enzyme to be more thermostable while conserving the key catalytic residues. This process generated a novel collagenase (ColG-variant) harboring sixteen mutations compared to ColG, with a nearly 4℃ increase in melting temperature. Herein, we explored the potential of ColG-variant to further decrease the physical effort required for tooth delivery using our established ex-situ porcine jaw model. An average reduction of 11% was recorded in the force applied to extract roots of mandibular split first and second premolar teeth treated with ColG-variant, relative to those treated with ColG. Our results show for the first time the potential of engineering enzyme properties for dental medicine and further contribute to minimally invasive tooth extraction.

Enhancement of Collagen-I Levels in Human Gingival Fibroblasts by Small Molecule Activation of HIF-1α

Collagen is the most abundant protein in various mammalian tissues and has an essential role in various cellular processes. Collagen is necessary for food-related biotechnological applications such as cultivated meat, medical engineering, and cosmetics. High-yield expression of natural collagen from mammalian cells is challenging and not cost-effective. Thus, external collagen is obtained primarily from animal tissues. Under cellular hypoxia, overactivation of the transcription factor hypoxia-inducible factor (HIF) was shown to correlate with enhanced accumulation of collagen. Herein, we showed that the small molecule ML228, a known molecular activator of HIF, enhances the accumulation of collagen type-I in human fibroblast cells. We report an increase in collagen levels by 2.33 ± 0.33 when fibroblasts were incubated with 5 μM of ML228. Our experimental results demonstrated, for the first time, that external modulation of the hypoxia biological pathway can boost collagen levels in mammalian cells. Our findings pave the way for enhancing natural collagen production in mammals by altering cellular signaling pathways.

Single-cell transcriptomic analysis of oral masticatory and lining mucosa-derived mesenchymal stromal cells

AIM

To reveal the heterogeneity of ex vivo-cultured human mesenchymal stromal cells derived from either masticatory or lining oral mucosa.

MATERIALS AND METHODS

Cells were retrieved from the lamina propria of the hard palate and alveolar mucosa of three individuals. The analysis of transcriptomic-level differences was accomplished using single-cell RNA sequencing.

RESULTS

Cluster analysis clearly distinguished between cells from the masticatory and lining oral mucosa, and revealed 11 distinct cell sub-populations, annotated as fibroblasts, smooth muscle cells or mesenchymal stem cells. Interestingly, cells presenting a mesenchymal stem cell-like gene expression pattern were predominantly found in masticatory mucosa. Although cells of masticatory mucosa origin were highly enriched for biological processes associated with wound healing, those from the lining oral mucosa were highly enriched for biological processes associated with the regulation of epithelial cells.

CONCLUSIONS

Our previous work had shown that cells from the lining and masticatory oral mucosae are phenotypically heterogeneous. Here, we extend these findings to show that these changes are not the result of differences in averages but rather represent two distinct cell populations, with mesenchymal stem cells more common in masticatory mucosa. These features may contribute to specific physiological functions and have relevance for potential therapeutic interventions.

Willingness to vaccinate children against COVID-19 declined during the pandemic

OBJECTIVES

To document the level of vaccine hesitancy in caregivers' of children younger than 12 years of age over the course of the pandemic in Pediatric Emergency Departments (ED). Study design Ongoing multicenter, cross-sectional survey of caregivers presenting to 19 pediatric EDs in the USA, Canada, Israel, and Switzerland during first months of the pandemic (phase1), when vaccines were approved for adults (phase2) and most recently when vaccines were approved for children (phase3).

RESULTS

Willingness to vaccinate rate declined over the study period (59.7%, 56.1% and 52.1% in the three phases). Caregivers who are fully vaccinated, who have higher education, and those worried their child had COVID-19 upon arrival to the ED, were more likely to plan to vaccinate in all three phases. Mothers were less likely to vaccinate early in the pandemic, but this hesitancy attenuated in later phases. Older caregivers were more willing to vaccinate, and caregivers of older children were less likely to vaccinate their children in phase 3. During the last phase, willingness to vaccinate was lowest in those who had a primary care provider but did not rely on their advice for medical decisions (34%). Those with no primary care provider and those who do and rely on their medical advice, had similar rates of willingness to vaccinate (55.1% and 52.1%, respectively).

CONCLUSIONS

COVID-19 vaccine hesitancy is widespread and growing over time, and public health measures should further try to leverage identified factors associated with hesitancy in order to enhance vaccination rates among children.

Collagenase Administration into Periodontal Ligament Reduces the Forces Required for Tooth Extraction in an Ex situ Porcine Jaw Model

Minimally invasive exodontia is among the long-sought-for development aims of safe dental medicine. In this paper, we aim, for the first time, to examine whether the enzymatic disruption of the periodontal ligament fibers reduces the force required for tooth extraction. To this end, recombinantly expressed clostridial collagenase G variant purified from Escherichia coli was injected into the periodontal ligament of mesial and distal roots of the first and second split porcine mandibular premolars. The vehicle solution was injected into the corresponding roots on the contralateral side. Following sixteen hours, the treated mandibles were mounted on a loading machine to measure the extraction force. In addition, the effect of the enzyme on the viability of different cell types was evaluated. An average reduction of 20% in the applied force (albeit with a large variability of 50 to 370 newton) was observed for the enzymatically treated roots, reaching up to 50% reduction in some cases. Importantly, the enzyme showed only a minor and transient effect on cellular viability, without any signs of toxicity. Using an innovative model enabling the analytical measurement of extraction forces, we show, for the first time, that the enzymatic disruption of periodontal ligament fibers substantially reduces the force required for tooth extraction. This novel technique brings us closer to atraumatic exodontia, potentially reducing intra- and post-operative complications and facilitating subsequent implant placement. The development of novel enzymes with enhanced activity may further simplify the tooth extraction process and present additional clinical relevance for the broad range of implications in the oral cavity.

'Why have women not returned to use their frozen oocytes?': a 5-year follow-up of women after planned oocyte cryopreservation

RESEARCH QUESTION

What are the reproductive choices and retrospective reflections of women at least 4 years after planned oocyte cryopreservation (POC)?

DESIGN

This was an internet survey, using the REDCap application, of women who underwent POC, at a single-centre university-affiliated IVF unit, 4-8 years before the survey. The questionnaire addressed reproductive choices and outcomes following POC.

RESULTS

Seventy-nine women who underwent POC during 2011-2014 were invited to participate, and 70 (89%) responded. Mean age at cryopreservation was 37.1 ± 2.4 (range 30-41) years, mean age at study participation 42.6 ± 2.6 (range 35-48) years, and mean time from first cryopreservation cycle to study participation 5.5 ± 1.3 (range 4-8) years. The main retrospectively reported reason for POC was not wanting to become pregnant without a partner (59, 84%). During the follow-up period, 44 women (63%) attempted to conceive either naturally or by assisted reproductive technology using fresh or cryopreserved oocytes. Of those, 28 women achieved a live birth (64% of those who tried to conceive). Fourteen respondents (20% of all respondents) reported using their cryopreserved oocytes, and three (21%) achieved a birth using those oocytes. Fifteen women (34%) of those who tried to conceive used donor spermatozoa.

CONCLUSIONS

The most common reasons for not using frozen oocytes were achieving pregnancy without frozen oocytes or preferring not to have a child without a partner. A considerable proportion of women who had POC and were not interested in being a single parent by choice eventually try to conceive using donor spermatozoa several years later.

Discovery and characterization of small molecule inhibitors of cystathionine gamma-synthase with in planta activity

The synthesis of essential amino acids in plants is pivotal for their viability and growth, and these cellular pathways are therefore targeted for the discovery of new molecules for weed control. Herein, we describe the discovery and design of small molecule inhibitors of cystathionine gamma-synthase, a key enzyme in the biosynthesis of methionine. Based on in silico screening and filtering of a large molecular database followed by the in vitro selection of molecules, we identified small molecules capable of binding the target enzyme. Molecular modelling of the interaction and direct biophysical binding enabled us to explore a focussed chemical expansion set of molecules characterized by an active phenyl-benzamide chemical group. These molecules are bio-active and efficiently inhibit the viability of BY-2 tobacco cells and seedlings growth of Arabidopsis thaliana on agar plates.

Screening Collagenase Activity in Bacterial Lysate for Directed Enzyme Applications

Collagenases are essential enzymes capable of digesting triple-helical collagen under physiological conditions. These enzymes play a key role in diverse physiological and pathophysiological processes. Collagenases are used for diverse biotechnological applications, and it is thus of major interest to identify new enzyme variants with improved characteristics such as expression yield, stability, or activity. The engineering of new enzyme variants often relies on either rational protein design or directed enzyme evolution. The latter includes screening of a large randomized or semirational genetic library, both of which require an assay that enables the identification of improved variants. Moreover, the assay should be tailored for microplates to allow the screening of hundreds or thousands of clones. Herein, we repurposed the previously reported fluorogenic assay using 3,4-dihydroxyphenylacetic acid for the quantitation of collagen, and applied it in the detection of bacterial collagenase activity in bacterial lysates. This enabled the screening of hundreds of E. coli colonies expressing an error-prone library of collagenase G from C. histolyticum, in 96-well deep-well plates, by measuring activity directly in lysates with collagen. As a proof-of-concept, a single variant exhibiting higher activity than the starting-point enzyme was expressed, purified, and characterized biochemically and computationally. This showed the feasibility of this method to support medium-high throughput screening based on direct evaluation of collagenase activity.

P–448 Clinical outcome of social oocyte cryopreservation at advanced age

Study question

What are the success rates of social oocyte cryopreservation (SOC) at advanced age?

Summary answer

In this study, one in four women who underwent SOC above age 35 had a delivery.

What is known already

While SOC is gaining popularity, reports on delivery rates are limited due to low utilization rates.

Study design, size, duration

Retrospective data collection of all woman who underwent SOC between 2011–2018, and presented for treatment using cryopreserved oocytes until January 2021. Participants/materials, setting, methods: Review of patient records (including both IVF and antenatal/postnatal) and laboratory data in a university affiliated hospital-based IVF unit. Main results and the role of chance: A total of 448 women underwent SOC during 2011–2018. 50 (11.2%) women returned to use these oocytes until the end of January 2021. Women who returned to use their oocytes underwent cryopreservation at mean age of 38.2±2.2. 46 (92%) of participants were above 35 at time of cryopreservation. Number of oocytes cryopreserved was 11.3±9.7. Mean time from cryopreservation to thawing was 5.5±1.8years (range 1–9 years). and age at thawing was 43.4±2.1 (range 40–49). Nearly half of patients initially attempted to conceive before using their cryopreserved oocytes, mostly by ART using fresh oocytes. Mean number of oocytes thawed and oocytes survived per women was 9.7±6.2 and 6.1±4.9 respectively (post thawing survival rate 65.4±35%).

Mean number of embryos transferred, at one or more attempts was 2.6±2.1 per women. Eleven women gave birth or had an ongoing pregnancy > 20 weeks at time of analysis. All deliveries resulted from cryopreservation at age 36 and older (delivery rate 23.9% per women). Limitations, reasons for caution: We report our initial experience of women who underwent SOC at a single center. Most women who returned to use their oocytes had undergone SOC at advanced age, therefore not necessarily reflecting outcome for younger patients attempting to preserve fertility using this technology. Wider implications of the findings: Considering modest success rates of SOC in our cohort, women considering SOC are advised to do so at an earlier age.

Trial registration number

Not applicable

Intracellular Protein-Drug Interactions Probed by Direct Mass Spectrometry of Cell Lysates

Understanding protein–ligand interactions in a cellular context is an important goal in molecular biology and biochemistry, and particularly for drug development. Investigators must demonstrate that drugs penetrate cells and specifically bind their targets. Towards that end, we present a native mass spectrometry (MS)‐based method for analyzing drug uptake and target engagement in eukaryotic cells. This method is based on our previously introduced direct‐MS method for rapid analysis of proteins directly from crude samples. Here, direct‐MS enables label‐free studies of protein–drug binding in human cells and is used to determine binding affinities of lead compounds in crude samples. We anticipate that this method will enable the application of native MS to a range of problems where cellular context is important, including protein–protein interactions, drug uptake and binding, and characterization of therapeutic proteins.

What the public think about participation in medical research during an influenza pandemic: an international cross-sectional survey

OBJECTIVES

The public and patients are primary contributors and beneficiaries of pandemic-relevant clinical research. However, their views on research participation during a pandemic have not been systematically studied. We aimed to understand public views regarding participation in clinical research during a hypothetical influenza pandemic.

STUDY DESIGN

This is an international cross-sectional survey.

METHODS

We surveyed the views of nationally representative samples of people in Belgium, Poland, Spain, Ireland, the United Kingdom, Canada, Australia and New Zealand, using a scenario-based instrument during the 2017 regional influenza season. Descriptive and regression analyses were conducted.

RESULTS

Of the 6804 respondents, 5572 (81.8%) thought pandemic-relevant research was important, and 5089 (74.8%) thought 'special rules' should be applied to make this research feasible. The respondents indicated willingness to take part in lower risk (4715, 69.3%) and higher risk (3585, 52.7%) primary care and lower risk (4780, 70.3%) and higher risk (4113, 60.4%) intensive care unit (ICU) study scenarios. For primary care studies, most (3972, 58.4%) participants preferred standard enrolment procedures such as prospective written informed consent, but 2327 (34.2%) thought simplified procedures would be acceptable. For ICU studies, 2800 (41.2%) preferred deferred consent, and 2623 (38.6%) preferred prospective third-party consent. Greater knowledge about pandemics, trust in a health professional, trust in the government, therapeutic misconception and having had ICU experience as a patient or carer predicted increased willingness to participate in pandemic-relevant research.

CONCLUSIONS

Our study indicates current public support for pandemic-relevant clinical research. Tailored information and initiatives to advance research literacy and maintain trust are required to support pandemic-relevant research participation and engagement.

Optimized small-molecule pull-downs define MLBP1 as an acyl-lipid-binding protein

Abscisic acid (ABA) receptors belong to the START domain superfamily, which encompasses ligand-binding proteins present in all kingdoms of life. START domain proteins contain a central binding pocket that, depending on the protein, can couple ligand binding to catalytic, transport or signaling functions. In Arabidopsis, the best characterized START domain proteins are the 14 PYR/PYL/RCAR ABA receptors, while the other members of the superfamily do not have assigned ligands. To address this, we used affinity purification of biotinylated proteins expressed transiently in Nicotiana benthamiana coupled to untargeted LC-MS to identify candidate binding ligands. We optimized this method using ABA-PYL interactions and show that ABA co-purifies with wild-type PYL5 but not a binding site mutant. The K_d of PYL5 for ABA is 1.1 μm, which suggests that the method has sufficient sensitivity for many ligand-protein interactions. Using this method, we surveyed a set of 37 START domain-related proteins, which resulted in the identification of ligands that co-purified with MLBP1 (At4G01883) or MLP165 (At1G35260). Metabolite identification and the use of authentic standards revealed that MLBP1 binds to monolinolenin, which we confirmed using recombinant MLBP1. Monolinolenin also co-purified with MLBP1 purified from transgenic Arabidopsis, demonstrating that the interaction occurs in a native context. Thus, deployment of this relatively simple method allowed us to define a protein-metabolite interaction and better understand protein-ligand interactions in plants.

Inhibition of PD1:PD-L1 interaction by an E. coli-derived optimized PD1 variant

Immune-checkpoint receptors are a set of signal transduction proteins that can stimulate or inhibit specific anti-tumor responses. It is well established that cancer cells interact with different immune checkpoints to shut down T-cell response, thereby enabling cancer proliferation. Given the importance of immune checkpoint receptors, a structure-function analysis of these systems is imperative. However, recombinant expression and purification of these membrane originated proteins is still a challenge. Therefore, many attempts are being made to improve their expression and solubility while preserving their biological relevance. For this purpose, we designed an E. coli-based optimization system that enables the acquisition of mutations that increases protein solubility and affinity towards its native ligand, while maintaining biological activity. Here we focused on the well-characterized extracellular domain of the 'programmed cell death protein 1' (PD1), an immune checkpoint receptor known to inhibit T-cell proliferation by interacting with its ligands PD-L1 and PD-L2. The simple ELISA-based screening system shown here enabled the identification of high-affinity, highly soluble, functional variants derived from the extracellular domain of human PD1. The system was based on the expression of a GST-tagged variants library in E. coli, which enabled the selection of improved PD1 variants after a single optimization round. Within only two screening rounds, the most active variant showed a 5-fold higher affinity and 2.4-fold enhanced cellular activity as compared to the wild type protein. This scheme can be translated toward other types of challenging receptors toward development of research tools or alternative therapeutics.

A Small Molecule Inhibitor of Bruton's Tyrosine Kinase Involved in B-Cell Signaling

Protein kinases are fundamental within almost all cellular signal transduction networks. Among these, Bruton's tyrosine kinase (Btk), which belongs to the Tec family of proteins, plays an imperative part in B-cell signaling. Owing to its role, Btk has been established as an important therapeutic target for a vast range of disorders related to B-cell development and function, such as the X-linked agammaglobulinemia, various B-cell malignancies, inflammation, and autoimmune diseases. Herein, using computer-based screening of a library of 20 million small molecules, we identified a small molecule capable of directly binding the Btk kinase domain. On the basis of this hit compound, we conducted a focused structure-similarity search to explore the effect of different chemical modifications on binding toward Btk. This search identified the molecule N2,N6-bis(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-9H-purine-2,6-diamine as a potent inhibitor of Btk. The latter small molecule binds Btk with a dissociation constant of 250 nM and inhibits Btk activity both in vitro and in-cell.

HP1BP3 expression determines maternal behavior and offspring survival

Maternal care is an indispensable behavioral component necessary for survival and reproductive success in mammals, and postpartum maternal behavior is mediated by an incompletely understood complex interplay of signals including effects of epigenetic regulation. We approached this issue using our recently established mice with targeted deletion of heterochromatin protein 1 binding protein 3 (HP1BP3), which we found to be a novel epigenetic repressor with critical roles in postnatal growth. Here, we report a dramatic reduction in the survival of pups born to Hp1bp3(-/-) deficient mouse dams, which could be rescued by co-fostering with wild-type dams. Hp1bp3(-/-) females failed to retrieve both their own pups and foster pups in a pup retrieval test, and showed reduced anxiety-like behavior in the open-field and elevated-plus-maze tests. In contrast, Hp1bp3(-/-) females showed no deficits in behaviors often associated with impaired maternal care, including social behavior, depression, motor coordination and olfactory capability; and maintained unchanged anxiety-associated hallmarks such as cholinergic status and brain miRNA profiles. Collectively, our results suggest a novel role for HP1BP3 in regulating maternal and anxiety-related behavior in mice and call for exploring ways to manipulate this epigenetic process.

Efficient Isothermal Titration Calorimetry Technique Identifies Direct Interaction of Small Molecule Inhibitors with the Target Protein

Protein-protein interactions (PPI) play a critical role in regulating many cellular processes. Finding novel PPI inhibitors that interfere with specific binding of two proteins is considered a great challenge, mainly due to the complexity involved in characterizing multi-molecular systems and limited understanding of the physical principles governing PPIs. Here we show that the combination of virtual screening techniques, which are capable of filtering a large library of potential small molecule inhibitors, and a unique secondary screening by isothermal titration calorimetry, a label-free method capable of observing direct interactions, is an efficient tool for finding such an inhibitor. In this study we applied this strategy in a search for a small molecule capable of interfering with the interaction of the tumor-suppressor p53 and the E3-ligase MDM2. We virtually screened a library of 15 million small molecules that were filtered to a final set of 80 virtual hits. Our in vitro experimental assay, designed to validate the activity of mixtures of compounds by isothermal titration calorimetry, was used to identify an active molecule against MDM2. At the end of the process the small molecule (4S,7R)-4-(4-chlorophenyl)-5-hydroxy-2,7-dimethyl-N-(6-methylpyridin-2-yl)-4,6,7,8 tetrahydrIoquinoline-3-carboxamide was found to bind MDM2 with a dissociation constant of ~2 µM. Following the identification of this single bioactive compound, spectroscopic measurements were used to further characterize the interaction of the small molecule with the target protein. 2D NMR spectroscopy was used to map the binding region of the small molecule, and fluorescence polarization measurement confirmed that it indeed competes with p53.

Multidimensional NMR spectroscopy in a single scan

Multidimensional NMR has become one of the most widespread spectroscopic tools available to study diverse structural and functional aspects of organic and biomolecules. A main feature of multidimensional NMR is the relatively long acquisition times that these experiments demand. For decades, scientists have been working on a variety of alternatives that would enable NMR to overcome this limitation, and deliver its data in shorter acquisition times. Counting among these methodologies is the so-called ultrafast (UF) NMR approach, which in principle allows one to collect arbitrary multidimensional correlations in a single sub-second transient. By contrast to conventional acquisitions, a main feature of UF NMR is a spatiotemporal manipulation of the spins that imprints the chemical shift and/or J-coupling evolutions being sought, into a spatial pattern. Subsequent gradient-based manipulations enable the reading out of this information and its multidimensional correlation into patterns that are identical to those afforded by conventional techniques. The current review focuses on the fundamental principles of this spatiotemporal UF NMR manipulation, and on a few of the methodological extensions that this form of spectroscopy has undergone during the years.

Analytic laboratory performance of a point of care urine culture kit for diagnosis and antibiotic susceptibility testing

Currently available point-of-care (POC) diagnostic tests for managing urinary tract infections (UTIs) in general practice are limited by poor performance characteristics, and laboratory culture generally provides results only after a few days. This laboratory evaluation compared the analytic performance of the POC UK Flexicult(™) (Statens Serum Institut) (SSI) urinary kit for quantification, identification and antibiotic susceptibility testing and routine UK National Health Service (NHS) urine processing to an advanced urine culture method. Two hundred urine samples routinely submitted to the Public Health Wales Microbiology Laboratory were divided and: (1) analysed by routine NHS microbiological tests as per local laboratory standard operating procedures, (2) inoculated onto the UK Flexicult(™) SSI urinary kit and (3) spiral plated onto Colorex Orientation UTI medium (E&O Laboratories Ltd). The results were evaluated between the NHS and Flexicult(™ )methods, and discordant results were compared to the spiral plating method. The UK Flexicult(™) SSI urinary kit was compared to routine NHS culture for identification of a pure or predominant uropathogen at ≥ 10(5) cfu/mL, with a positive discordancy rate of 13.5% and a negative discordancy rate of 3%. The sensitivity and specificity were 86.7% [95% confidence interval (CI) 73.8-93.7] and 82.6% (95% CI 75.8-87.7), respectively. The UK Flexicult(™) SSI urinary kit was comparable to routine NHS urine processing in identifying microbiologically positive UTIs in this laboratory evaluation. However, the number of false-positive samples could lead to over-prescribing of antibiotics in clinical practice. The Flexicult(™) SSI kit could be useful as a POC test for UTIs in primary care but further pragmatic evaluations are necessary.

NMR resonance assignments of the catalytic domain of human serine/threonine phosphatase calcineurin in unligated and PVIVIT-peptide-bound states

Calcineurin (Cn) is a serine/threonine phosphatase that plays pivotal roles in many physiological processes. In T cell, Cn targets the nuclear factors of activated T-cell (NFATs), transcription factors that activate cytokine genes. Elevated intracellular calclium concentration activates Cn to dephosphorylate multiple serine residues within the NFAT regulatory domain, which triggers joint nuclear translocation of NFAT and Cn. This relies on the interaction between the catalytic domain of Cn (CnA) and the conserved PxIxIT motif. Here, we present the assignment of CnA resonances in unligated form and in complex with a 14-residue peptide containing a PVIVIT sequence that was derived from affinity driven peptide selection based on the conserved PxIxIT motif of NFATs. Although a complete assignment was not possible mainly due to the paramagnetic line broadening induced by an iron in the CnA catalytic center, the assignment was extensively verified by amino-acid selective labeling of Arg, Leu, Lys, and Val, which cover one third of the CnA residues. Nevertheless, the assignments were used to determine the structure of the CnA-PVIVIT peptide complex and provide the basis for investigation of the interactions of CnA with physiological interaction partners and small organic compounds that disrupt the Cn-NFAT interaction.

The LxVP and PxIxIT NFAT motifs bind jointly to overlapping epitopes on calcineurin's catalytic domain distant to the regulatory domain

The serine/threonine phosphatase calcineurin (Cn) targets the nuclear factors of activated T cells (NFATs) that activate cytokine genes. Calcium influx activates Cn to dephosphorylate multiple serine residues within the ∼200 residue NFAT regulatory domain, which triggers joint nuclear translocation of NFAT and Cn. The dephosphorylation process relies on the interaction between Cn and the conserved motifs PxIxIT and LxVP, which are located N- and C-terminal to the phosphorylation sites in NFAT's regulatory domain. Here, we show that an NFATc1-derived 15-residue peptide segment containing the conserved LxVP motif binds to an epitope on Cn's catalytic domain (CnA), which overlaps with the previously established PxIxIT binding site on CnA and is distant to the regulatory domain (CnB). Both NFAT motifs partially compete for binding but do not fully displace each other on the CnA epitope, revealing that both segments bind simultaneously to the same epitope on the catalytic domain.

Speeding up direct (15)N detection: hCaN 2D NMR experiment

Experiments detecting low gyromagnetic nuclei have recently been proposed to utilize the relatively slow relaxation properties of these nuclei in comparison to (1)H. Here we present a new type of (15)N direct-detection experiment. Like the previously proposed CaN experiment (Takeuchi et al. in J Biomol NMR 47:271-282, 2010), the hCaN experiment described here sequentially connects amide (15)N resonances, but utilizes the initial high polarization and the faster recovery of the (1)H nucleus to shorten the recycling delay. This allows recording 2D (15)N-detected NMR experiments on proteins within a few hours, while still obtaining superior resolution for (13)C and (15)N, establishing sequential assignments through prolines, and at conditions where amide protons exchange rapidly. The experiments are demonstrated on various biomolecules, including the small globular protein GB1, the 22 kDa HEAT2 domain of eIF4G, and an unstructured polypeptide fragment of NFAT1, which contains many SerPro sequence repeats.

Absent gallbladder on fetal ultrasound: prenatal findings and postnatal outcome

OBJECTIVES

Fetal gallbladder non-visualization on prenatal ultrasound in the second trimester is uncommon and in most cases the gallbladder is detected eventually. Associations of gallbladder non-visualization with cystic fibrosis, aneuploidy, agenesis of the gallbladder and biliary atresia have been reported. We present our experience and review the literature.

METHODS

During the study period from January 2004 to June 2009 we collected prospectively cases of non-visualization of the fetal gallbladder in the second trimester. In each case the fetus was evaluated by two examiners on at least two occasions, at least a week apart. Cases with no additional sonographic malformations were designated as isolated. Further evaluation included follow-up scans and a meticulous search for fetal anomalies. All patients were offered genetic consultation. Cystic fibrosis testing, amniocentesis for karyotyping and analysis of fetal digestive enzymes in the amniotic fluid were offered.

RESULTS

We collected 21 cases of non-visualization of the fetal gallbladder, 16 of which were isolated and five of which had additional malformations. In four of these five, the associated anomalies were severe and the pregnancies were terminated for aneuploidy (two cases of trisomy 18 and one triploidy) or for the severity of the associated anomalies. Associated anomalies included left isomerism with complex cardiac anomaly and intrauterine growth restriction with multisystem anomalies. The fifth fetus had interrupted inferior vena cava with azygos continuation without other anomalies and the child was alive and well at the age of 4 years. In 15 of the 16 isolated cases, antenatal and postnatal development were normal at the last follow-up, ranging from 4 months to 2.5 years. One case of cystic fibrosis was diagnosed prenatally and this pregnancy was terminated. There were no diagnoses of abnormal karyotype or biliary atresia among cases of isolated non-visualization of the gallbladder.

CONCLUSIONS

When prenatal non-visualization of the fetal gallbladder is associated with other severe malformation, aneuploidy should be suspected. When it is isolated, if cystic fibrosis is ruled out, the outcome is good.

HNCA-TOCSY-CANH experiments with alternate (13)C- (12)C labeling: a set of 3D experiment with unique supra-sequential information for mainchain resonance assignment

Described here is a set of three-dimensional (3D) NMR experiments that rely on CACA-TOCSY magnetization transfer via the weak ³J(CαCα) coupling. These pulse sequences, which resemble recently described (13)C detected CACA-TOCSY (Takeuchi et al. 2010) experiments, are recorded in (1)H(2)O, and use (1)H excitation and detection. These experiments require alternate (13)C-(12)C labeling together with perdeuteration, which allows utilizing the small ³J(CαCα) scalar coupling that is otherwise masked by the stronger (1)J(CC) couplings in uniformly (13)C labeled samples. These new experiments provide a unique assignment ladder-mark that yields bidirectional supra-sequential information and can readily straddle proline residues. Unlike the conventional HNCA experiment, which contains only sequential information to the ¹³C(α) of the preceding residue, the 3D hnCA-TOCSY-caNH experiment can yield sequential correlations to alpha carbons in positions i-1, i + 1 and i-2. Furthermore, the 3D hNca-TOCSY-caNH and Hnca-TOCSY-caNH experiments, which share the same magnetization pathway but use a different chemical shift encoding, directly couple the (15)N-(1)H spin pair of residue i to adjacent amide protons and nitrogens at positions i-2, i-1, i + 1 and i + 2, respectively. These new experimental features make protein backbone assignments more robust by reducing the degeneracy problem associated with the conventional 3D NMR experiments.

A capacitively coupled temperature-jump arrangement for high-resolution biomolecular NMR

A simple design for performing rapid temperature jumps within a high-resolution nuclear magnetic resonance (NMR) setting is presented and exemplified. The design is based on mounting, around a conventional NMR glass tube, an inductive radiofrequency (RF) irradiation coil that is suitably tuned by a resonant circuit and is driven by one of the NMR's console high-power RF amplifiers. The electric fields generated by this coil's thin metal strips can lead to a fast and efficient heating of the sample, amounting to temperature jumps of ≈ 20 °C in well within a second-particularly in the presence of lossy dielectric media like those provided by physiological buffers. Moreover, when wound around a 4-mm NMR tube, the resulting device fits a conventional 5-mm inverse probe and is wholly compatible with the field homogeneities and sensitivities expected for high-resolution biomolecular NMR conditions. The performance characteristics of this new system were tested using saline solutions, as well as on a lyotropic liquid crystal capable of undergoing nematic → isotropic transitions in the neighborhood of ambient temperature. These settings were then incorporated into the performance of a new kind of single-scan 2D NMR spectroscopy acquisition, correlating the anisotropic and isotropic patterns elicited by solutes dissolved in such liquid-crystalline systems, before and after a sudden temperature jump occurring during an intervening mixing period.

Single-scan 2D NMR correlations by multiple coherence transfers

A new scheme for the acquisition of heteronuclear 2D correlations in NMR spectroscopy within a single scan, is proposed and demonstrated. The principles of this new scheme resemble those of Mansfield's "k-space walk" proposal, in the sense that they rely on repetitively transferring spin coherences back-and-forth between the two spin systems to be correlated. It is shown that if properly executed, these transfers enable the equivalent of a continuous sampling of the time-domain space supporting a 2D heteronuclear single-quantum correlation NMR spectrum. Details on how to execute the resulting "time-domain walk" experiments are given, and examples comparing it against conventional and other single-scan 2D acquisition alternatives are shown. Advantages, opportunities, and main drawbacks of this new ultrafast approach to 2D NMR, are briefly discussed.

Native-unlike long-lived intermediates along the folding pathway of the amyloidogenic protein beta2-microglobulin revealed by real-time two-dimensional NMR

Beta2-microglobulin (beta2m), the light chain of class I major histocompatibility complex, is responsible for the dialysis-related amyloidosis and, in patients undergoing long term dialysis, the full-length and chemically unmodified beta2m converts into amyloid fibrils. The protein, belonging to the immunoglobulin superfamily, in common to other members of this family, experiences during its folding a long-lived intermediate associated to the trans-to-cis isomerization of Pro-32 that has been addressed as the precursor of the amyloid fibril formation. In this respect, previous studies on the W60G beta2m mutant, showing that the lack of Trp-60 prevents fibril formation in mild aggregating condition, prompted us to reinvestigate the refolding kinetics of wild type and W60G beta2m at atomic resolution by real-time NMR. The analysis, conducted at ambient temperature by the band selective flip angle short transient real-time two-dimensional NMR techniques and probing the beta2m states every 15 s, revealed a more complex folding energy landscape than previously reported for wild type beta2m, involving more than a single intermediate species, and shedding new light into the fibrillogenic pathway. Moreover, a significant difference in the kinetic scheme previously characterized by optical spectroscopic methods was discovered for the W60G beta2m mutant.

An improved ultrafast 2D NMR experiment: towards atom-resolved real-time studies of protein kinetics at multi-Hz rates

Multidimensional NMR spectroscopy is a well-established technique for the characterization of structure and fast-time-scale dynamics of highly populated ground states of biological macromolecules. The investigation of short-lived excited states that are important for molecular folding, misfolding and function, however, remains a challenge for modern biomolecular NMR techniques. Off-equilibrium real-time kinetic NMR methods allow direct observation of conformational or chemical changes by following peak positions and intensities in a series of spectra recorded during a kinetic event. Because standard multidimensional NMR methods required to yield sufficient atom-resolution are intrinsically time-consuming, many interesting phenomena are excluded from real-time NMR analysis. Recently, spatially encoded ultrafast 2D NMR techniques have been proposed that allow one to acquire a 2D NMR experiment within a single transient. In addition, when combined with the SOFAST technique, such ultrafast experiments can be repeated at high rates. One of the problems detected for such ultrafast protein NMR experiments is related to the heteronuclear decoupling during detection with interferences between the pulses and the oscillatory magnetic field gradients arising in this scheme. Here we present a method for improved ultrafast data acquisition yielding higher signal to noise and sharper lines in single-scan 2D NMR spectra. In combination with a fast-mixing device, the recording of (1)H-(15)N correlation spectra with repetition rates of up to a few Hertz becomes feasible, enabling real-time studies of protein kinetics occurring on time scales down to a few seconds.

[Betel quid and oral cancer: case report]

Betel quid chewing is a major cause of oral cancers in Asia. Practitioners must be able to recognize premalignant lesions. Cessation of betel quid use and preventive treatment must be recommended. Primary prevention will be difficult because of the traditional nature and commercial importance of this old habit.

[Extracting a foreign body from the nasal fossa without an ENT specialist]

Foreign bodies in the nasal fossa are frequent and generally occur in children. In developing countries, access to an ENT specialist can be difficult or impossible. The authors describe several extraction techniques with special emphasis on those best suited to areas with limited access to specialist facilities. Using illustrations, a step-by-step description of the so-called "hook" technique is given. This simple technique allows successful removal of a foreign body from the nasal fossa in almost all cases.

Spatially encoded strategies in the execution of biomolecular-oriented 3D NMR experiments

Three-dimensional nuclear magnetic resonance (3D NMR) provides one of the foremost analytical tools available for the elucidation of biomolecular structure, function and dynamics. Executing a 3D NMR experiment generally involves scanning a series of time-domain signals S(t3), as a function of two time variables (t1, t2) which need to undergo parametric incrementations throughout independent experiments. Recent years have witnessed extensive efforts towards the acceleration of this kind of experiments. Among the different approaches that have been proposed counts an "ultrafast" scheme, which distinguishes itself from other propositions by enabling--at least in principle--the acquisition of the complete multidimensional NMR data set within a single transient. 2D protein NMR implementations of this single-scan method have been demonstrated, yet its potential for 3D acquisitions has only been exemplified on model organic compounds. This publication discusses a number of strategies that could make these spatial encoding protocols compatible with 3D biomolecular NMR applications. These include a merging of 2D ultrafast NMR principles with temporal 2D encoding schemes, which can yield 3D HNCO spectra from peptides and proteins within approximately 100 s timescales. New processing issues that facilitate the collection of 3D NMR spectra by relying fully on spatial encoding principles are also assessed, and shown capable of delivering HNCO spectra within 1 s timescales. Limitations and prospects of these various schemes are briefly addressed.

Stage at breast cancer diagnosis is more advanced in BRCA1 carriers but not in BRCA2 carriers

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Background: BRCA1-associated tumors are known to have less favorable pathological characteristics, but there is little information on whether this is also reflected in the stage at diagnosis. Methods: Clinical and pathological information was collected on 1,122 consecutive Ashkenazi Jewish breast cancer patients who were tested post-diagnosis for the BRCA1/2 mutations common in this population. Results: Of 1,122 patients, 70 (6.2%) were BRCA1 and 50 (4.5%) were BRCA2 carriers. Mean age at diagnosis was 49.9 yrs. in BRCA1 carriers (p=.0001 vs. non-carriers (NC)) vs. 52.0 yrs. in BRCA2 carriers (p=.02 vs. NC) and 56.0 yrs. in NC. Pure DCIS was less common in BRCA1 carriers (3%) than in BRCA2 carriers (8.2%) and NC (11.8%) (p=.03). Medullary carcinoma was more common in BRCA1 (9.8%) and BRCA2 carriers (6.7%) than in NC (1.5%) (p<.001). Invasive lobular carcinomas were rarer in BRCA1 (1.6%) and BRCA2 (2.2%) compared to NC (8.8%) (p=.012). Hormone receptors (HR) negative was more common in BRCA1 (62%) compared to BRCA2 carriers (21%) (p=.00006) and NC (17%) (p<0.0001). Triple negative tumors (HR and HER2 negative) were more common in BRCA1 carriers (60%) than in BRCA2 carriers (14%) and NC (8.3%) (p=0.001). High grade was more common in BRCA1 (60.4%) and BRCA2 (51.4%) carriers than in NC (36.7%, p=.001). Less favorable pathological features and younger age at diagnosis in BRCA1 carriers were reflected in a more advanced stage at diagnosis. Stage I at diagnosis was found in 34% of BRCA1 carriers (p=.05 vs. NC), 43% of BRCA2 carriers and 46% of NC, stage II in 48% of BRCA1 carriers, 41% of BRCA2 carriers and 37% of NC, and stage III in 17% of BRCA1 carriers, 13.5% of BRCA2 carriers and 13.5% of non-carriers. Conclusions: This consecutive cohort study demonstrates that breast cancers in BRCA1 carriers are characterized by more aggressive pathological features and are diagnosed at more advanced stages than in BRCA2 carriers and non-carriers. This may suggest a differential approach for prevention and surveillance in BRCA1 compared to BRCA2 carriers.

No significant financial relationships to disclose.

Lidocaine–Prilocaine (EMLA) cream as analgesia for hysterosalpingography: a prospective, randomized, controlled, double blinded study

BACKGROUND

The aim of our study is to evaluate the efficacy of applying lidocaine 25 mg-prilocaine-25 mg/G cream (EMLA 5%) on the uterine cervix for pain relief when performing hysterosalpingography (HSG).

METHODS

Eighty-two patients undergoing HSG as part of infertility evaluation were randomized into groups receiving EMLA (42) or placebo cream (40) in a double-blinded prospective study from which four women were later excluded. The cream was applied to the uterine cervix by means of a cervical cup 30 min before the HSG. Pain perception related to the HSG procedure was scored by visual analogue scale (VAS) at five predefined steps: after speculum application, after cervical instrumentation of the tenaculum and cannula, at the end of uterine filling, at completion of tubal spillage, and immediately following instrument removal. In addition, the patients were asked to retrospectively rate the pain during the entire procedure in a telephone interview the following day.

RESULTS

Cervical instrumentation was found to be the most painful step of HSG (P < 0.001). When comparing the VAS pain scores, cervical instrumentation in the EMLA-treated patients was associated with significantly less pain than the control group: 3.3 +/- 2.9 versus 4.9 +/- 2.7, respectively (P = 0.02).

CONCLUSIONS

Topical application of EMLA 5% cream on the uterine cervix before performing HSG significantly reduced the pain during this procedure.

UltraSOFAST HMQC NMR and the Repetitive Acquisition of 2D Protein Spectra at Hz Rates

Following unidirectional biophysical events such as the folding of proteins or the equilibration of binding interactions, requires experimental methods that yield information at both atomic-level resolution and at high repetition rates. Toward this end a number of different approaches enabling the rapid acquisition of 2D NMR spectra have been recently introduced, including spatially encoded "ultrafast" 2D NMR spectroscopy and SOFAST HMQC NMR. Whereas the former accelerates acquisitions by reducing the number of scans that are necessary for completing arbitrary 2D NMR experiments, the latter operates by reducing the delay between consecutive scans while preserving sensitivity. Given the complementarities between these two approaches it seems natural to combine them into a single tool, enabling the acquisition of full 2D protein NMR spectra at high repetition rates. We demonstrate here this capability with the introduction of "ultraSOFAST" HMQC NMR, a spatially encoded and relaxation-optimized approach that can provide 2D protein correlation spectra at approximately 1 s repetition rates for samples in the approximately 2 mM concentration range. The principles, relative advantages, and current limitations of this new approach are discussed, and its application is exemplified with a study of the fast hydrogen-deuterium exchange characterizing amide sites in Ubiquitin.