One-shot skill assessment in high-stakes domains with limited data via meta learning

Deep Learning (DL) has achieved robust competency assessment in various high-stakes fields. However, the applicability of DL models is often hampered by their substantial data requirements and confinement to specific training domains. This prevents them from transitioning to new tasks where data is scarce. Therefore, domain adaptation emerges as a critical element for the practical implementation of DL in real-world scenarios. Herein, we introduce A-VBANet, a novel meta-learning model capable of delivering domain-agnostic skill assessment via one-shot learning. Our methodology has been tested by assessing surgical skills on five laparoscopic and robotic simulators and real-life laparoscopic cholecystectomy. Our model successfully adapted with accuracies up to 99.5 % in one-shot and 99.9 % in few-shot settings for simulated tasks and 89.7 % for laparoscopic cholecystectomy. This study marks the first instance of a domain-agnostic methodology for skill assessment in critical fields setting a precedent for the broad application of DL across diverse real-life domains with limited data.

Assessment of Surgical Tasks Using Neuroimaging Dataset (ASTaUND)

Functional near-infrared spectroscopy (fNIRS) is a neuroimaging tool for studying brain activity in mobile subjects. Open-access fNIRS datasets are limited to simple and/or motion-restricted tasks. Here, we report a fNIRS dataset acquired on mobile subjects performing Fundamentals of Laparoscopic Surgery (FLS) tasks in a laboratory environment. Demonstrating competency in the FLS tasks is a prerequisite for board certification in general surgery in the United States. The ASTaUND data set was acquired over four different studies. We provide the relevant information about the hardware, FLS task execution protocols, and subject demographics to facilitate the use of this open-access data set. We also provide the concurrent FLS scores, a quantitative metric for surgical skill assessment developed by the FLS committee. This data set is expected to support the growing field of assessing surgical skills via neuroimaging data and provide an example of data processing pipeline for use in realistic, non-restrictive environments.

Assessing the Risks to Bats from Plant Protection Products: A Review of the Recent European Food Safety Authority Statement Regarding Toxicity and Exposure Routes

Wild birds and mammals that feed in agricultural habitats are potentially exposed to pesticides through various routes. Until recently, it has been implicitly assumed that the existing European Union risk assessment scheme for birds and mammals also covered bats (Chiroptera). However, recent publications raised concerns and, in 2019, a scientific statement was published by the European Food Safety Authority (EFSA) that concluded that bats were not adequately covered by the current risk assessment scheme. We review the evidence presented and assumptions made in the EFSA bat statement relating to toxicity, bioaccumulation, and exposure pathways (oral, dermal, and inhalation), in terms of their relevance for bats potentially foraging in agricultural areas in the European Union; we highlight where uncertainties remain and how these could be addressed. Based on our review, it is clear that there is still much uncertainty with regard to the appropriateness of the assumptions made in the EFSA bat statement. Significantly more information needs to be gathered to answer fundamental questions regarding bat behavior in agricultural landscapes, together with the relative sensitivity of bats to pesticide exposure. Given the current critical information gaps, it is recommended that quantitative risk assessments for bats not be performed for pesticides until more robust, reliable, and relevant data are available. The risk to bats can then be compared with that for birds and ground-dwelling mammals, to determine the protectiveness of the existing scheme and thus whether a bat scenario is indeed required and under what circumstances. Environ Toxicol Chem 2021;40:2978-2989. © 2021 Cambridge Environmental Assessments, part of RSK ADAS Ltd. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

BurnCare tablet trainer to enhance burn injury care and treatment

BACKGROUND

Applied Research Associates (ARA) and the United States Army Institute of Surgical Research (USAISR) have been developing a tablet-based simulation environment for burn wound assessment and burn shock resuscitation. This application aims to supplement the current gold standard in burn care education, the Advanced Burn Life Support (ABLS) curriculum.

RESULTS

Subject matter experts validate total body surface area (TBSA) identification and analysis and show that the visual fidelity of the tablet virtual patients is consistent with real life thermal injuries. We show this by noting that the error between their burn mapping and the actual patient burns was sufficiently less than that of a random sample population. Statistical analysis is used to confirm this hypothesis. In addition a full body physiology model developed for this project is detailed. Physiological results, and responses to standard care treatment, are detailed and validated. Future updates will include training modules that leverage this model.

CONCLUSION

We have created an accurate, whole-body model of burn TBSA training experience in Unreal 4 on a mobile platform, provided for free to the medical community. We hope to provide learners with more a realistic experience and with rapid feedback as they practice patient assessment, intervention, and reassessment.

The effect of autostereoscopic holograms on anatomical knowledge: a randomised trial

CONTEXT

Three-dimensional (3-D) visualisation in anatomical education has been shown to be broadly beneficial for students. However, there is limited research on the relative efficacy of 3-D modalities. This study compares knowledge performance, mental effort and instructional efficiency between autostereoscopic 3-D visualisation (holograms), monoscopic 3-D visualisation (3-DPDFs) and a control (2-D printed images).

METHODS

A cardiac anatomy model was used to generate holograms, 3-DPDFs and 2-D printed images. Nursing student participants (n = 179) were randomised into three groups: holograms (n = 60), 3-DPDFs (n = 60) and printed images (n = 59). Participants completed a pre-test followed by a self-study period using the anatomical visualisation. Afterwards, participants completed the NASA-Task Load Index (NASA-TLX) cognitive load instrument and a knowledge post-test.

RESULTS

Post-test results showed participants studying with holograms (median = 80.0, interquartile range [IQR] = 66.7-86.7) performed significantly better regarding cardiac anatomy knowledge than participants using 3-DPDF (median = 66.7, IQR = 53.3-80.0, p = 0.008) or printed images (median = 66.7, IQR = 53.3-80.0, p = 0.007). Mental effort scores, on a scale from 1 to 20, showed hologram (mean = 4.9, standard deviation [SD] = 3.56) and 3-DPDF participants (mean = 4.9, SD = 3.79) reported significantly lower cognitive load than printed images (mean = 7.5, SD = 4.9, p < 0.005). Instructional efficiency (E) of holograms (E = 0.35) was significantly higher than printed images (E = -0.36, p < 0.001), although not significantly higher than 3-DPDF (E = 0.03, p = 0.097).

CONCLUSIONS

Participants using holograms demonstrated significant knowledge improvement over printed images and monoscopic 3-DPDF models, suggesting additional depth cues from holographic visualisation provide benefit in understanding spatial anatomy. Mental effort scores and instructional efficiency of holograms indicate holograms are a cognitively efficient instructional medium. These findings highlight the need for further study of novel 3-D technologies and learning performance.

Comparison of inherently essential genes of Porphyromonas gingivalis identified in two transposon-sequencing libraries

Porphyromonas gingivalis is a Gram-negative anaerobe and keystone periodontal pathogen. A mariner transposon insertion mutant library has recently been used to define 463 genes as putatively essential for the in vitro growth of P. gingivalis ATCC 33277 in planktonic culture (Library 1). We have independently generated a transposon insertion mutant library (Library 2) for the same P. gingivalis strain and herein compare genes that are putatively essential for in vitro growth in complex media, as defined by both libraries. In all, 281 genes (61%) identified by Library 1 were common to Library 2. Many of these common genes are involved in fundamentally important metabolic pathways, notably pyrimidine cycling as well as lipopolysaccharide, peptidoglycan, pantothenate and coenzyme A biosynthesis, and nicotinate and nicotinamide metabolism. Also in common are genes encoding heat-shock protein homologues, sigma factors, enzymes with proteolytic activity, and the majority of sec-related protein export genes. In addition to facilitating a better understanding of critical physiological processes, transposon-sequencing technology has the potential to identify novel strategies for the control of P. gingivalis infections. Those genes defined as essential by two independently generated TnSeq mutant libraries are likely to represent particularly attractive therapeutic targets.

Real-time passive tracking for multi-touch medical modeling and simulation

The military medical community expects to minimize use of live tissue and cadavers for training purposes. This research demonstrates an innovative use of synthetic tissue and passive tracking computer vision to create a real-time, interactive environment for training medical staff.

Monoterpene concentrations in fresh, senescent, and decaying foliage of singleleaf pinyon (Pinus monophylla Torr. & Frem.: Pinaceae) from the western Great Basin

Senescent foliage from pines is potentially a large contributor to the total monoterpene content of the litter layer, and the availability of these compounds as phytotoxins may result from release of these compounds into the vapor phase. In order to determine the fate of several monoterpene hydrocarbons in the natural environment, we examined their concentrations in fresh, senescent, and decaying needles from 32 single-leaf pinyon pine (Pinus monophylla Torr. & Frem.: Pinaceae) trees growing at two different locations. Total monoterpene content was highest in the fresh needles (mean=5.6 ± 2.2 mg/g extracted air dry weight), but also remained relatively high in senescent needles (mean=3.6 ±1.8 mg/g extracted air dry weight), either still attached to the tree or forming the freshest layer of understory litter. Decaying needles within a dark decomposing layer of litter material 5-20 cm from the surface were found to contain much lower amounts of total monoterpenes (average: =0.12 ±0.06 mg/g extracted air dry weight). Further investigation of the fate of these compounds in the pinyon understory is required to determine if these hydrocarbons are indeed exerting phytotoxic characteristics.

Regulon controlled by the GppX hybrid two component system in Porphyromonas gingivalis

The periodontal pathogen Porphyromonas gingivalis experiences a number of environmental conditions in the oral cavity, and must monitor and respond to a variety of environmental cues. However, the organism possesses only five full two-component systems, one of which is the hybrid system GppX. To investigate the regulon controlled by GppX we performed RNA-Seq on a ΔGppX mutant. Fifty-three genes were upregulated and 37 genes were downregulated in the ΔGppX mutant. Pathway analyses revealed no systemic function for GppX under nutrient-replete conditions; however, over 40% of the differentially abundant genes were annotated as encoding hypothetical proteins indicating a novel role for GppX. Abundance of small RNA was, in general, not affected by the absence of GppX. To further define the role of GppX with respect to regulation of a hypothetical protein observed with the greatest significant relative abundance change relative to a wild-type control, PGN_0151, we constructed a series of strains in which the ΔgppX mutation was complemented with a GppX protein containing specific domain and phosphotransfer mutations. The transmembrane domains, the DNA-binding domain and the phosphotransfer residues were all required for regulation of PGN_0151. In addition, binding of GppX to the PGN_0151 promoter regions was confirmed by an electrophoretic mobility shift assay. Both the ΔGppX mutant and a ΔPGN_0151 mutant were deficient in monospecies biofilm formation, suggesting a role for the GppX-PGN_0151 regulon in colonization and survival of the organism.

Design and rationale of the tobacco, exercise and diet messages (TEXT ME) trial of a text message-based intervention for ongoing prevention of cardiovascular disease in people with coronary disease: a randomised controlled trial protocol

Background Although supporting lifestyle change is an effective way of preventing further events in people with cardiovascular disease, providing access to such interventions is a major challenge. This study aims to investigate whether simple reminders about behaviour change sent via mobile phone text message decrease cardiovascular risk. Methods and analysis Randomised controlled trial with 6 months of follow-up to evaluate the feasibility, acceptability and effect on cardiovascular risk of repeated lifestyle reminders sent via mobile phone text messages compared to usual care. A total of 720 patients with coronary artery disease will be randomised to either standard care or the TEXT ME intervention. The intervention group will receive multiple weekly text messages that provide information, motivation, support to quit smoking (if relevant) and recommendations for healthy diets and exercise. The primary end point is a change in plasma low-density lipoprotein cholesterol at 6 months. Secondary end points include a change in systolic blood pressure, smoking status, quality of life, medication adherence, waist circumference, physical activity levels, nutritional status and mood at 6 months. Process outcomes related to acceptability and feasibility of TEXT ME will also be collected. Ethics and dissemination Primary ethics approval was received from Western Sydney Local Health Network Human Research Ethics Committee-Westmead. Results will be disseminated via the usual scientific forums including peer-reviewed publications and presentations at international conferences. Clinical trials registration number ACTRN12611000161921.

Cognitive function and risks of cardiovascular disease and hypoglycaemia in patients with type 2 diabetes: the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) trial

AIMS/HYPOTHESIS

The relationship between cognitive function, cardiovascular disease and premature death is not well established in patients with type 2 diabetes. We assessed the effects of cognitive function in 11,140 patients with type 2 diabetes who participated in the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) trial. Furthermore, we tested whether level of cognitive function altered the beneficial effects of the BP-lowering and glycaemic-control regimens in the trial.

METHODS

Cognitive function was assessed using the Mini Mental State Examination at baseline, and defined by scores 28-30 ('normal', n = 8,689), 24-27 ('mild dysfunction', n = 2,231) and <24 ('severe dysfunction', n = 212). Risks of major cardiovascular events, death and hypoglycaemia and interactions with treatment were assessed using Cox proportional hazards analysis.

RESULTS

Relative to normal function, both mild and severe cognitive dysfunction significantly increased the multiple-adjusted risks of major cardiovascular events (HR 1.27, 95% CI 1.11-1.46 and 1.42, 95% CI 1.01-1.99; both p < 0.05), cardiovascular death (1.41, 95% CI 1.16-1.71 and 1.56, 95% CI 0.99-2.46; both p <or= 0.05) and all-cause death (1.33, 95% CI 1.16-1.54 and 1.50, 95% CI 1.06-2.12; both p < 0.03). Severe, but not mild, cognitive dysfunction increased the risk of severe hypoglycaemia (HR 2.10, 95% CI 1.14-3.87; p = 0.018). There was no evidence of heterogeneity of treatment effects on cardiovascular outcomes in subgroups defined by cognitive function at baseline.

CONCLUSIONS/INTERPRETATION

Cognitive dysfunction is an independent predictor of clinical outcomes in patients with type 2 diabetes, but does not modify the effects of BP lowering or glucose control on the risks of major cardiovascular events.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00145925.

Tools for interpreting large-scale protein profiling in microbiology

Quantitative proteomic analysis of microbial systems generates large datasets that can be difficult and time-consuming to interpret. Fortunately, many of the data display and gene-clustering tools developed to analyze large transcriptome microarray datasets are also applicable to proteomes. Plots of abundance ratio vs. total signal or spectral counts can highlight regions of random error and putative change. Displaying data in the physical order of the genes in the genome sequence can highlight potential operons. At a basic level of transcriptional organization, identifying operons can give insights into regulatory pathways as well as provide corroborating evidence for proteomic results. Classification and clustering algorithms can group proteins together by their abundance changes under different conditions, helping to identify interesting expression patterns, but often work poorly with noisy data such as typically generated in a large-scale proteomic analysis. Biological interpretation can be aided more directly by overlaying differential protein abundance data onto metabolic pathways, indicating pathways with altered activities. More broadly, ontology tools detect altered levels of protein abundance for different metabolic pathways, molecular functions, and cellular localizations. In practice, pathway analysis and ontology are limited by the level of database curation associated with the organism of interest.

Complete genome sequence of the genetically tractable hydrogenotrophic methanogen Methanococcus maripaludis

The genome sequence of the genetically tractable, mesophilic, hydrogenotrophic methanogen Methanococcus maripaludis contains 1,722 protein-coding genes in a single circular chromosome of 1,661,137 bp. Of the protein-coding genes (open reading frames [ORFs]), 44% were assigned a function, 48% were conserved but had unknown or uncertain functions, and 7.5% (129 ORFs) were unique to M. maripaludis. Of the unique ORFs, 27 were confirmed to encode proteins by the mass spectrometric identification of unique peptides. Genes for most known functions and pathways were identified. For example, a full complement of hydrogenases and methanogenesis enzymes was identified, including eight selenocysteine-containing proteins, with each being paralogous to a cysteine-containing counterpart. At least 59 proteins were predicted to contain iron-sulfur centers, including ferredoxins, polyferredoxins, and subunits of enzymes with various redox functions. Unusual features included the absence of a Cdc6 homolog, implying a variation in replication initiation, and the presence of a bacterial-like RNase HI as well as an RNase HII typical of the Archaea. The presence of alanine dehydrogenase and alanine racemase, which are uniquely present among the Archaea, explained the ability of the organism to use L- and D-alanine as nitrogen sources. Features that contrasted with the related organism Methanocaldococcus jannaschii included the absence of inteins, even though close homologs of most intein-containing proteins were encoded. Although two-thirds of the ORFs had their highest Blastp hits in Methanocaldococcus jannaschii, lateral gene transfer or gene loss has apparently resulted in genes, which are often clustered, with top Blastp hits in more distantly related groups.

Related IgA1 and IgG producing cells in blood and diseased mucosa in ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory bowel disease in which the colonic mucosa is infiltrated with plasma cells producing IgG autoantibodies. It is not known whether this represents a local mucosal response which has switched to IgG or a peripheral response which may have been initiated by peripheral antigen which homed to the colonic mucosa. The clonal distribution of IgG secreting cells and isotype switched variants in UC is not known.

AIMS

To investigate the clonal distribution of mucosal IgG in UC and to search for related IgG and IgA secreting cells in normal and diseased mucosa and blood in UC. To investigate characteristics which may discriminate between the mucosal and peripheral repertoire in the normal mucosa and in UC.

PATIENTS

Blood and normal and diseased mucosa from two patients with UC were studied.

METHODS

Immunoglobulin gene analysis and clone specific polymerase chain reaction were used to study the clonal distribution and characteristics of IgG and related IgA in the mucosa and blood of patients with UC.

RESULTS

The IgG response in the mucosa of UC patients included widespread clones of cells that were present in both the diseased mucosa and blood but that were scarce in normal mucosa. Clonally related IgA class switch variants, all IgA1, were detected but also only in the diseased mucosa and blood. This suggests that these clones home preferentially to the diseased mucosa. We showed that J(H)1 usage was characteristic of the peripheral repertoire, and that examples of J(H)1 usage were observed in mucosal IgG in UC.

CONCLUSIONS

Overall, these data are consistent with a model of UC in which a peripheral response is expressed and expanded in the colonic mucosa.

Mass spectrometric analysis of recombinant adenylate cyclase toxin from Bordetella pertussis strain 18323/pHSP9

The adenylate cyclase toxin-hemolysin (ACT) is a key virulence factor of the whooping cough agent Bordetella pertussis (Bp). The major cytotoxic activity of this 1706-residue protein consists of its capacity to invade a variety of eukaryotic cells directly across their cytoplasmic membrane and to deliver into cells a catalytic adenylate cyclase domain. This causes impairment of immune effector cells and apoptosis of lung macrophages by uncontrolled conversion of ATP to cAMP. The adenylate cyclase toxin-hemolysin acquires biological activity upon post-translational amide-linked palmitoylation of the epsilon-amino group of lysine 983 (K983) by the accessory fatty acyltransferase, CyaC. However, an additional conserved acylation site can be identified in ACT at lysine 860 (K860) and this residue is palmitoylated when recombinant ACT is produced in Escherichia coli (r-Ec-ACT). In this paper we report the double acylation of r-Bp-ACT secreted by a recombinant Bp strain 18323/pHSP9. This strain overproduces ACT from an oligocopy plasmid carrying the entire cya locus of Bordetella pertussis 18323. Palmitoylation of both conserved lysines (K860 and K983) of r-Bp-ACT expressed by this Bp strain was found. In addition, an error in the deduced protein sequence was identified, with Leu being the real residue at position 1001 and not the Val residue given in the published gene sequence. We also discuss these results in comparison with those from recombinant ACT expressed in E. coli strain K12 XL1-Blue. The analytical approach for characterization of the fatty acylation of ACT from strain 18323/pHSP9 consisted of multiple proteolytic digestion procedures (trypsin, Asp-N), microcapillary liquid chromatography/tandem mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Acylation of lysine 983 is sufficient for toxin activity of Bordetella pertussis adenylate cyclase. Substitutions of alanine 140 modulate acylation site selectivity of the toxin acyltransferase CyaC

The capacity of adenylate cyclase toxin (ACT) to penetrate into target cells depends on post-translational fatty-acylation by the acyltransferase CyaC, which can palmitoylate the conserved lysines 983 and 860 of ACT. Here, the in vivo acylating capacity of a set of mutated CyaC acyltransferases was characterized by two-dimensional gel electrophoresis and mass spectrometric analyses of the ACT product. Substitutions of the potentially catalytic serine 20 and histidine 33 residues ablated acylating activity of CyaC. Conservative replacements of alanine 140 by glycine (A140G) and valine (A140V) residues, however, affected selectivity of CyaC for the two acylation sites on ACT. Activation by the A140G variant of CyaC generated a mixture of bi- and monoacylated ACT molecules, modified either at both Lys-860 and Lys-983, or only at Lys-860, respectively. In contrast, the A140V CyaC produced a nearly 1:1 mixture of nonacylated pro-ACT with ACT monoacylated almost exclusively at Lys-983. The respective proportion of toxin molecules acylated at Lys-983 correlated well with the cell-invasive activity of both ACT mixtures, which was about half of that of ACT fully acylated on Lys-983 by intact CyaC. These results show that acylation of Lys-860 alone does not confer cell-invasive activity on ACT, whereas acylation of Lys-983 is necessary and sufficient.

Searching the Porphyromonas gingivalis genome with peptide fragmentation mass spectra

An approach is described for genomic database searching based on experimentally observed proteolytic fragments, e.g., isolated from 1D or 2D gels or analyzed directly, that can be applied to unfinished prokaryotic genomic data in the absence of annotations or previously assigned open reading frames (ORFs). This variation on the database search is in contrast to the more familiar use of peptide mass spectral fragmentation data to search fully annotated inferred protein databases, e.g., OWL or SWISS-PROT. We compared the SEQUEST search results from a six reading frame translation of the Porphyromonas gingivalis genome DNA sequence with those from computationally derived ORFs created using publicly available genomics software tools. The ORF approach eliminated many of the artifacts present in output from the six reading frame search. The method was applied to uninterpreted tandem mass spectrometric data derived from proteins secreted by the periodontal pathogen Porphyromonas gingivalis in response to the gingival epithelial cell environment, a model system for the study of host-pathogen interactions relevant to human periodontal disease.

Escherichia coli alpha-hemolysin (HlyA) is heterogeneously acylated in vivo with 14-, 15-, and 17-carbon fatty acids

alpha-Hemolysin (HlyA) is a secreted protein virulence factor observed in certain uropathogenic strains of Escherichia coli. The active, mature form of HlyA is produced by posttranslational modification of the protoxin that is mediated by acyl carrier protein and an acyltransferase, HlyC. We have now shown using mass spectrometry that these modifications, when observed in protein isolated in vivo, consist of acylation at the epsilon-amino groups of two internal lysine residues, at positions 564 and 690, with saturated 14- (68%), 15- (26%), and 17- (6%) carbon amide-linked side chains. Thus, HlyA activated in vivo consists of a heterogeneous family of up to nine different covalent structures, and the substrate specificity of the HlyC acyltransferase appears to differ from that of the closely related CyaC acyltransferase expressed by Bordetella pertussis.

A PhoP-regulated outer membrane protease of Salmonella enterica serovar typhimurium promotes resistance to alpha-helical antimicrobial peptides

The outer membrane protein contents of Salmonella enterica serovar Typhimurium strains with PhoP/PhoQ regulon mutations were compared by two-dimensional gel electrophoresis. At least 26 species of outer membrane proteins (OMPs) were identified as being regulated by PhoP/PhoQ activation. One PhoP/PhoQ-activated OMP was identified by semiautomated tandem mass spectrometry coupled with electronic database searching as PgtE, a member of the Escherichia coli OmpT and Yersinia pestis Pla family of outer membrane proteases. Salmonella PgtE expression promoted resistance to alpha-helical cationic antimicrobial peptides (alpha-CAMPs). Strains expressing PgtE cleaved C18G, an 18-residue alpha-CAMP present in culture medium, indicating that protease activity is likely to be the mechanism of OmpT-mediated resistance to alpha-CAMPs. PhoP/PhoQ did not regulate the transcription or export of PgtE, indicating that another PhoP/PhoQ-dependent mechanism is required for PgtE outer membrane localization. PgtE is a posttranscriptionally regulated component of the PhoP/PhoQ regulon that contributes to Salmonella resistance to innate immunity.

A remote flow cell for UV absorbance detection with capillary HPLC based on a single strand fiber optic

A remote flow cell based on a single strand of fused-silica fiber optic was built for UV absorbance detection with a packed capillary HPLC system, using commercially available pumps, detection electronics (Shimadzu) and fittings. This 'off-column' flow cell design is applicable to both pressure and electro-osmotically driven systems. The goals were to minimize the linearity and light leakage problems that often limit the performance of UV absorbance detection with capillary chromatography. A linear dynamic range of 10(3) (reserpine, lambda = 220 nm), and a concentration detection limit of 5.1 x 10(-8) mol l-1 were observed. Baseline noise was measured at 3.5 x 10(-5) absorbance units (AU), with a standard deviation of 1.7 x 10(-5) AU. The illuminated volume of approximately 3 nl was optimized for capillaries with inner diameters in the range 50-100 microns, and flow rates from 100 nl min-1 to 1 microliter min-1. These modifications of readily available instrumentation have allowed the construction of a practical system for fractionating complex mixtures of peptides in small amounts, prior to mass spectrometry or additional wet chemistry steps.

Rapid isolation method for lipopolysaccharide and lipid A from gram-negative bacteria

A fast, convenient extraction method for lipopolysaccharide (LPS), using a commercial RNA isolating reagent, allows the isolation of LPS or lipid A from low milligram (dry weight) quantities of bacterial cells. The method avoids the use of specialized equipment and has been used for processing relatively large numbers of samples. The major components of the commercial RNA isolating reagent, Tri-Reagent, are phenol and guanidinium thiocyanate in aqueous solution. The bacterial cell membranes are disrupted with guanidinium thiocyanate, which eliminates the need for mechanical cell disruption (e.g. French press) or heating. LPS and its degradation products, with particular attention paid to its bioactive lipid A portion, were measured and compared with those from the most common conventional extraction method, hot phenol-water. Negative ion quadrupole ion trap and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, fatty acid composition analysis by capillary gas chromatography, total and free phosphate by UV spectrophotometry and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed that LPS and lipid A isolated using the Tri-Reagent approach were cleaner and suffered less degradation through loss of phosphate and (or) fatty acyl side chains from lipid A. The Tri-Reagent extraction method generated low free phosphate contamination, 11% of the total phosphate concentration, whereas the hot phenol-water extraction method gave approximately 58% as free, inorganic phosphate. Similar results were observed for the degradation of fatty acyl side chains. The time required by the new method is considerably shorter (two or three days) than that required by conventional hot phenol-water extraction (about two weeks).

Characteristics of human IgA and IgM genes used by plasma cells in the salivary gland resemble those used in duodenum but not those used in the spleen

Immunologically, the parotid salivary gland is an effector site that secretes large quantities of polyspecific Abs into the saliva, mainly of the IgA isotype. It is considered to be part of the common mucosal immune system but the inductive site for the Ab-producing cells of the salivary gland has not yet been clearly identified. The origin and diversity of cells of B lineage can be investigated by analyzing their Ig heavy chain genes (IgH). We have obtained sequences of IgM and IgA VH4-34 genes from plasma cells in human salivary gland, duodenal lamina propria, and splenic red pulp. Related sequences were found in different areas sampled within each tissue studied, indicating that the plasma cells carrying these genes are widespread with limited diversity. Examples of related IgH genes that are isotype switched were also seen in the salivary gland. The genes from plasma cells of the salivary gland were highly mutated, as were duodenal plasma cell sequences. The level of mutation was significantly higher than that seen in splenic plasma cell sequences. Analysis of CDR3 regions showed that the sequences from salivary gland had significantly smaller CDR3 regions than sequences from spleen, due to differences in number and type of DH regions used. Sequences from duodenum also had smaller CDR3 regions. Therefore, plasma cells from human duodenum and salivary gland showed characteristics that differed from those of human splenic plasma cells.

Association of dialyzer reuse and hospitalization rates among hemodialysis patients in the US

OBJECTIVES

To determine if reuse of hemodialyzers is associated with higher rates of hospitalization and their resulting costs among end-stage renal disease (ESRD) patients.

METHODS

Noncurrent cohort study of hospitalization rates among 27,264 ESRD patients beginning hemodialysis in the United States in 1986 and 1987.

RESULTS

Dialysis in free-standing facilities reprocessing dialyzers was associated with a greater rate of hospitalization than in facilities not reprocessing (relative rate (RR) = 1.08, 95% confidence interval (CI), 1.02-1.14). This higher rate of hospitalization was observed with dialyzer reuse using peracetic/acetic acids (RR = 1.11, CI 1. 04-1.18) and formaldehyde (RR = 1.07, CI 1.00-1.14), but not glutaraldehyde (p = 0.97). There was no difference among hospitalization rates in hospital-based facilities reprocessing dialyzers with any sterilant and those not reprocessing. Hospitalization for causes other than vascular access morbidity in free-standing facilities reusing dialyzers with formaldehyde was not different from hospitalization in facilities not reusing. However, reuse with peracetic/acetic acids was associated with higher rates of hospitalization than formaldehyde (RR = 1.08, CI 1.03-1.15).

CONCLUSIONS

Dialysis in free-standing facilities reprocessing dialyzers with peracetic/acetic acids or formaldehyde was associated with greater hospitalization than dialysis without dialyzer reprocessing. This greater hospitalization accounts for a large increment in inpatient stays in the USA. These findings raise important concerns about potentially avoidable morbidity among hemodialysis patients.

Specific lipopolysaccharide found in cystic fibrosis airway Pseudomonas aeruginosa

Cystic fibrosis (CF) patients develop chronic airway infections with Pseudomonas aeruginosa (PA). Pseudomonas aeruginosa synthesized lipopolysaccharide (LPS) with a variety of penta- and hexa-acylated lipid A structures under different environmental conditions. CF patient PA synthesized LPS with specific lipid A structures indicating unique recognition of the CF airway environment. CF-specific lipid A forms containing palmitate and aminoarabinose were associated with resistance to cationic antimicrobial peptides and increased inflammatory responses, indicating that they are likely to be involved in airway disease.

Clinical governance: culture, leadership and power--the key to changing attitudes and behaviours in trusts

Clinical governance places for legal duty for quality on Trust chief executives. The article deals with how chief executives can overcome the cultural and behavioural obstacles to change which impede the journey to developing effective structures for clinical governance. To establish effective structures for clinical governance, chief executives will need to address these features of organisational life--culture, power and leadership. The article seeks to provide practical ways in which they can do this.

Helicobacter pylori treatment and antibiotic susceptibility: results of a five-year audit

BACKGROUND

Helicobacter pylori eradication treatment has been a rapidly evolving field. Audit of treatment results provides reassurance that trial data can be translated into routine clinical practice.

METHODS

Data were collected prospectively over five years. Patients were given four different treatment regimens over the audit period 'standard' triple therapy, two types of clarithromycin-based treatment or ranitidine, amoxycillin and metronidazole. Eradication was proven by a urea breath test at least four weeks after completing treatment.

RESULTS

Eradication treatment for H. pylori was given to 665 patients; 89% had follow-up data. H. pylori eradication was significantly associated with treatment type (p<0.0001) and smoking (p=0.04) by univariate analysis, but was not associated with sex, age, alcohol consumption, endoscopic diagnosis, recent treatment with anti-secretory drugs or NSAIDs. By logistic regression analysis, only treatment type was significant (p=0.0001). H. pylori culture and sensitivities were available for 255 patients. Metronidazole resistance was shown for 84 isolates (32%) and clarithromycin resistance for 18 isolates (6.8%). Metronidazole resistance was significantly associated with younger age (p=0.02), ethnicity (p=0.02), female sex (p=0.02), and year of endoscopy (p=0.04), but was not associated with clarithromycin resistance. Clarithromycin resistance was not associated with age, sex, or ethnicity. Metronidazole resistance significantly affected H. pylori eradication for regimens containing metronidazole without clarithromycin. Eradication with metronidazole without clarithromycin was achieved in 90% of sensitive strains but only 55% of resistant strains (p<0.001). Metronidazole resistance was not significantly associated with treatment failure when metronidazole was combined with clarithromycin. Eradication with metronidazole and clarithromycin was achieved in 86% of sensitive strains and 78% of resistant strains (p=0.42).

CONCLUSION

Treatment type and antibiotic susceptibility are the most important determinants of treatment success.

Developing our leaders in the future

The role of the chief executive in a transformed organisation is an extremely challenging one. The development of vision, building a commitment to it and communicating it constantly are key skills for a chief executive. However, the need to build and empower the stakeholders within and outside the organisation to support the changes required to deliver the vision requires leaders who can connect with a wide range of people and build alliances and partnerships to secure organisational success. A passion for understanding human intervention and behaviour is needed to encourage, cajole and drive teams and individuals to own and commit to change and a new direction. This requires leaders who have imagination and creativity--who seek connections and thread them together to create order out of incoherence. These skills are not taught in schools or textbooks, but are probably innate. They are what separate leaders from the rest. These skills need to be developed. A movement towards encouraging experimentation, career transfers and more individuality is needed if capable leaders of the future are to appear.

Developing consultant care on delivery suite

The need to develop a consultant presence on the delivery suite has never been greater given the emerging quality agenda that is occurring within the speciality. This is identifying a clear impetus for changing consultant practice and also meeting the needs of women more effectively. The article describes these trends, the impetus for change and identifies practically how such a change was achieved within the largest women's hospital in the UK. It defines the basis for building a vision for an improved future and the practical use of management and transformational leadership skills to change consultant behaviour and attitudes with a clear set of outcomes that were achieved.

Developing postgraduate medical education for trusts: a secret to long-term success

The delivery of effective postgraduate education for doctors in trusts is becoming vital to secure the individual services of trusts. Increasingly, training requirements are impacting on the location of clinical services that NHS trusts provide. Failure to understand the benefits and drawbacks of providing postgraduate education could affect the long-term strategic direction of trusts. The paper seeks to identify the case for investment, the need to address key deliverables to secure effective postgraduate education and the need for clinicians and managers to evaluate the effectiveness of such training for their organisations.

The conserved lysine 860 in the additional fatty-acylation site of Bordetella pertussis adenylate cyclase is crucial for toxin function independently of its acylation status

The Bordetella pertussis RTX (repeat in toxin family protein) adenylate cyclase toxin-hemolysin (ACT) acquires biological activity upon a single amide-linked palmitoylation of the epsilon-amino group of lysine 983 (Lys983) by the accessory fatty-acyltransferase CyaC. However, an additional conserved RTX acylation site can be identified in ACT at lysine 860 (Lys860), and this residue becomes palmitoylated when recombinant ACT (r-Ec-ACT) is produced together with CyaC in Escherichia coli K12. We have eliminated this additional acylation site by replacing Lys860 of ACT with arginine, leucine, and cysteine residues. Two-dimensional gel electrophoresis and microcapillary high performance liquid chromatography/tandem mass spectrometric analyses of mutant proteins confirmed that the two sites are acylated independently in vivo and that mutations of Lys860 did not affect the quantitative acylation of Lys983 by palmitoyl (C16:0) and palmitoleil (cis Delta9 C16:1) fatty-acyl groups. Nevertheless, even the most conservative substitution of lysine 860 by an arginine residue caused a 10-fold decrease of toxin activity. This resulted from a 5-fold reduction of cell association capacity and a further 2-fold reduction in cell penetration efficiency of the membrane-bound K860R toxin. These results suggest that lysine 860 plays by itself a crucial structural role in membrane insertion and translocation of the toxin, independently of its acylation status.

Biased JH usage in plasma cell immunoglobulin gene sequences from colonic mucosa in ulcerative colitis but not in Crohn's disease

BACKGROUND

Ulcerative colitis is an inflammatory disease of the colonic and rectal mucosa. Autoantibodies have been observed in ulcerative colitis which may have a role in the pathogenesis of the disease. Evidence also suggests that there is an hereditary predisposition towards the disease, although no individual genes have been identified.

AIMS

This is a pilot study of immunoglobulin heavy chain genes (IgH) in ulcerative colitis to determine whether they have any particular genetic characteristics which may lead to a better understanding of the disease aetiology.

SUBJECTS

Colonic or rectal tissue was obtained from five children with ulcerative colitis. Tissue was also obtained from five children with Crohn's disease and five children who did not have inflammatory bowel disease as controls.

METHODS

B cells and IgD+ B cells were identified by immunohistochemistry on frozen sections. Areas of lamina propria containing plasma cells, and areas of IgD+ B cells were microdissected. The immunoglobulin genes were PCR amplified, cloned, and sequenced. Sequences were analysed for content of somatic mutations and composition of heavy chain.

RESULTS

An increase in the use of JH6 and DXP'1, and a decrease in the use of JH4, gene segments in immunoglobulin genes from lamina propria plasma cells, and from virgin IgD+ B cells, was found in patients with ulcerative colitis. These biases were not present in the control groups.

CONCLUSIONS

There is a fundamental difference in the immunoglobulin genes from patients with ulcerative colitis. Whether this is caused by a difference in content of immunoglobulin gene segments in the germline or a difference in the recombination mechanism is not known.

A cardioactive peptide from the southern armyworm, Spodoptera eridania

A cardioactive peptide was isolated from extracts of whole heads of the southern armyworm, Spodoptera eridania. This peptide has the sequence ENFAVGCTPGYQRTADGRCKPTF (Mr = 2516.8), determined from both Edman sequencing and tandem mass spectrometry in combination with off-line micropreparative capillary liquid chromatography. This peptide, termed Spoer-CAP23, has excitatory effects on a semi-isolated heart from larval Manduca sexta, causing an inotropic effect at low concentrations of peptide and chronotropic and inotropic effects at high doses. The threshold concentration for stimulatory effects of the synthetic peptide on the semi-isolated heart was about 1 nM, suggesting a physiological role as a neuropeptide.

Fragmentation pathways of selectively labeled uropranolol using electrospray ionization on an ion trap mass spectrometer and comparison with ions formed by electron impact

Propranolol, deuterium- and 18O-labeled propranolol and related compounds were analyzed using an ion trap mass spectrometer equipped with a modified Finnigan API electrospray interface. Sequential product ion (MSn) experiments were used to elucidate fragmentation pathways for these compounds. The observed ions were compared to those observed under electron impact (EI) conditions. The electrospray ionization (ESI) ion trap spectra, as well as the EI spectra, afford useful information to allow assignments of most product ions, many of which retain portions of the aliphatic three-carbon side chain.

Mass spectral fragmentation pathways of propranolol related beta-fluorinated amines studied by electrospray and electron impact ionization

Propranolol, its 1"-mono-, di-, and trifluorinated analogs, and other related compounds were analyzed under electrospray ionization ion trap collision-induced dissociation (ESI-CID) and electron impact (EI) conditions. Interesting trends were observed in the fragment ions formed in both cases. Under ESI conditions, the abundances of product ions easily explained by protonation on the amine nitrogen decreased relative to the abundances of those formed from the ether-protonated species as the number of fluorines increased from zero to three. Under EI conditions, the distribution of fragment ions was shifted away from those arising from a nitrogen-centered cation radical and toward those arising from an ether oxygen-centered cation radical. The changes observed in apparent molecular sites of protonation and of ion radical formation in the mass spectra are consistent with the electron-withdrawing effects of the sequentially added fluorines. These effects are correlated with changes in solution phase pK( a)'s of the fluorinated amines.

Potential utility of electronic drug compliance monitoring in measures of adverse outcomes associated with immunosuppressive agents

Poor compliance with prescribed medications limits the effectiveness of many pharmacologic therapies and enhances their potential toxicities. Traditional methods of measuring drug-taking behavior, including direct observation, patient self-report, pill counts, and therapeutic drug level monitoring, all have well-described limitations in validity and interpretability. Electronic medication event monitoring has been used to assess compliance with therapies for hypertension, glaucoma, anemia, and epilepsy, overcoming many problems of traditional approaches. However, no published reports describe the use of electronic monitoring with immunosuppressive agents, despite their increasing use for non-life-threatening conditions and their many dose-dependent toxicities. Transplant recipients are thought to be at particular risk from noncompliance. Therefore, we undertook this study to assess the feasibility of electronically monitoring compliance with immunosuppressive drugs among renal allograft recipients. Twenty-five kidney transplant patients receiving immunosuppressive medications from a single pharmacy were enrolled. Each subject received electronic monitors with their immunosuppressive serum drug refills for cyclosporine and azathioprine. Each subject returned their monitors after the first month of this 2-month study for downloading data. The frequency distribution of interdose intervals were described. Two measures of average non-compliance were calculated for both drugs: the proportion of monitored days that had missed doses, and the proportion of missed doses. Once daily and twice daily regimens of cyclosporine were compared. Concordance in drug compliance between the two drugs was calculated for each subject and averaged over the study population. Twenty-two of 25 subjects missed one or more doses of cyclosporine or azathioprine. Seventeen (68%) subjects never missed four or more consecutive doses. Subjects were non-compliant with cyclosporine on 8.7% of monitored days, and non-compliance with azathioprine on 9.8% of monitored days. Subjects were non-compliant with 6.8% of their cyclosporine doses and 9.8% of their azathioprine doses. Patients were compliant with both drugs on 86.6% of days and were non-compliant with both drugs on 5.1% of days. Subjects were non-compliant with cyclosporine during 5% and 13.2% of monitored days for once and twice daily dosing regimens, respectively. Concordance analysis demonstrated that for 91.7% of days of monitoring, compliance information was identical for both drugs. This study demonstrated the feasibility of electronic medication event monitoring among kidney transplant patients. This methodology represents an important tool for monitoring compliance of immunosuppressive agents essential to their safe and effective use, and should be considered for use in future studies of these drugs and others with substantial dose-dependent toxicity.

Lipid A acylation and bacterial resistance against vertebrate antimicrobial peptides

The Salmonellae PhoP-PhoQ virulence regulators induce resistance to host cationic antimicrobial peptides (CAMP) after infection of vertebrate tissues, and Mg2+ or Ca2+ limitation. The PhoP-PhoQ activated gene, pagP, was identified as important to inducible CAMP resistance and increased acylation of lipid A, the major component of the outer leaflet of the outer membrane. pagP mutants demonstrated increased outer membrane permeability in response to CAMP, supporting the hypothesis that increased lipid A acylation is a CAMP resistance mechanism. Similarly, in response to Mg2+ limited growth, other enteric Gram-negative bacteria demonstrated increased lipid A acylation. Compounds that inhibit the ability to increase lipid A acylation may have utility as new antimicrobial agents.

PmrA-PmrB-regulated genes necessary for 4-aminoarabinose lipid A modification and polymyxin resistance

Antimicrobial peptides are distributed throughout the animal kingdom and are a key component of innate immunity. Salmonella typhimurium regulates mechanisms of resistance to cationic antimicrobial peptides through the two-component systems PhoP-PhoQ and PmrA-PmrB. Polymyxin resistance is encoded by the PmrA-PmrB regulon, whose products modify the lipopolysaccharide (LPS) core and lipid A regions with ethanolamine and add aminoarabinose to the 4' phosphate of lipid A. Two PmrA-PmrB-regulated S. typhimurium loci (pmrE and pmrF) have been identified that are necessary for resistance to polymyxin and for the addition of aminoarabinose to lipid A. One locus, pmrE, contains a single gene previously identified as pagA (or ugd) that is predicted to encode a UDP-glucose dehydrogenase. The second locus, pmrF, is the second gene of a putative operon predicted to encode seven proteins, some with similarity to glycosyltransferases and other complex carbohydrate biosynthetic enzymes. Genes immediately flanking this putative operon are also regulated by PmrA-PmrB and/or have been associated with S. typhimurium polymyxin resistance. This work represents the first identification of non-regulatory genes necessary for modification of lipid A and subsequent antimicrobial peptide resistance, and provides support for the hypothesis that lipid A aminoarabinose modification promotes resistance to cationic antimicrobial peptides.

Role of the consultant obstetrician in the delivery suite

The role of consultant obstetricians is under considerable debate. This has particularly focused on the role of consultants in intrapartum care. The article explores the role of the consultant in delivery suite from the view point of a consultant, a clinical director, a training programme director and a chief executive. These viewpoints determine a range of common themes which mean the duties of consultants over their career lifecycle need to be addressed; the need to expand consultant posts; and the tensions which inevitably occur. The authors believe these need to be addressed because of the need to ensure consultant roles in delivery suite are developed as a key part of seeing quality improvement.

Developing new professional partnerships with acute Trusts and general practitioners

The development of locality commissioning models combined with demographic, therapeutic and service changes are driving new professional relationships between general practitioners and acute Trusts. To ensure a Trust releases its strategy in this environment, stakeholders must understand the benefits to be gained from these new levels of relationships. A review of the literature is undertaken and the conditions for successful partnerships between acute Trusts and general practitioners defined. The article determines that for acute Trusts it will mean an examination of core competences combined with a drive to "review" their organisations.