Predicting severe pain after major surgery: a secondary analysis of the Peri-operative Quality Improvement Programme (PQIP) dataset.

Acute postoperative pain is common, distressing and associated with increased morbidity. Targeted interventions can prevent its development. We aimed to develop and internally validate a predictive tool to pre-emptively identify patients at risk of severe pain following major surgery. We analysed data from the UK Peri-operative Quality Improvement Programme to develop and validate a logistic regression model to predict severe pain on the first postoperative day using pre-operative variables. Secondary analyses included the use of peri-operative variables. Data from 17,079 patients undergoing major surgery were included. Severe pain was reported by 3140 (18.4%) patients; this was more prevalent in females, patients with cancer or insulin-dependent diabetes, current smokers and in those taking baseline opioids. Our final model included 25 pre-operative predictors with an optimism-corrected c-statistic of 0.66 and good calibration (mean absolute error 0.005, p = 0.35). Decision-curve analysis suggested an optimal cut-off value of 20-30% predicted risk to identify high-risk individuals. Potentially modifiable risk factors included smoking status and patient-reported measures of psychological well-being. Non-modifiable factors included demographic and surgical factors. Discrimination was improved by the addition of intra-operative variables (likelihood ratio χ2 496.5, p < 0.001) but not by the addition of baseline opioid data. On internal validation, our pre-operative prediction model was well calibrated but discrimination was moderate. Performance was improved with the inclusion of peri-operative covariates suggesting pre-operative variables alone are not sufficient to adequately predict postoperative pain.

Nitrosopumilus maritimus genome reveals unique mechanisms for nitrification and autotrophy in globally distributed marine crenarchaea.

Ammonia-oxidizing archaea are ubiquitous in marine and terrestrial environments and now thought to be significant contributors to carbon and nitrogen cycling. The isolation of Candidatus "Nitrosopumilus maritimus" strain SCM1 provided the opportunity for linking its chemolithotrophic physiology with a genomic inventory of the globally distributed archaea. Here we report the 1,645,259-bp closed genome of strain SCM1, revealing highly copper-dependent systems for ammonia oxidation and electron transport that are distinctly different from known ammonia-oxidizing bacteria. Consistent with in situ isotopic studies of marine archaea, the genome sequence indicates N. maritimus grows autotrophically using a variant of the 3-hydroxypropionate/4-hydroxybutryrate pathway for carbon assimilation, while maintaining limited capacity for assimilation of organic carbon. This unique instance of archaeal biosynthesis of the osmoprotectant ectoine and an unprecedented enrichment of multicopper oxidases, thioredoxin-like proteins, and transcriptional regulators points to an organism responsive to environmental cues and adapted to handling reactive copper and nitrogen species that likely derive from its distinctive biochemistry. The conservation of N. maritimus gene content and organization within marine metagenomes indicates that the unique physiology of these specialized oligophiles may play a significant role in the biogeochemical cycles of carbon and nitrogen.

Counterion condensation theory of attraction between like charges in the absence of multivalent counterions.

There is abundant experimental evidence suggesting the existence of attractive interactions among identically charged polyelectrolytes in ordinary salt solutions. The presence of multivalent counterions is not required. We review the relevant literature in detail and conclude that it merits more attention than it has received. We discuss also some recent observations of a low ionic strength attraction of negatively charged DNA to the region of a negatively charged glass nanoslit where the floor of the nanoslit meets the walls, again in the absence of multivalent ions. On the theoretical side, it has become clear that purely electrostatic interactions require the presence of multivalent counterions if they are to generate like-charge attraction. Any theory of like-charge attraction in the absence of multivalent counterions must therefore contain a non-electrostatic component. We point out that counterion condensation theory, which has predicted like-charge polyelectrolyte attraction in an intermediate range of distances in ordinary 1:1 salt conditions, contains both electrostatic and non-electrostatic elements. The non-electrostatic component of the theory is the modeling constraint that the counterions fall into two explicit populations, condensed and uncondensed. As reviewed in the paper, this physically motivated constraint is supported by strong experimental evidence. We proceed to offer an explanation of the nanoslit observations by showing in an idealized model that the line of intersection of two intersecting planes is a virtual polyelectrolyte. Since we have previously developed a counterion condensation theory of attraction of two like-charged polyelectrolytes, our suggestion is that the DNA is attracted to the virtual polyelectrolytes that may be located in the nanoslit where floor meets walls. We present the detailed calculations needed to document this suggestion: an extension of previous theory to the case of polyelectrolytes with like but not identical charges; the demonstration of counterion condensation on a plane with bare charge density greater than an explicitly exhibited critical value; a calculation of the free energy of the plane; a calculation of the interaction of a line charge polyelectrolyte with a like-charged plane; and the detailed demonstration that the line of intersection of two planes is a virtual polyelectrolyte.

A counterion condensation theory for the relaxation, rise, and frequency dependence of the parallel polarization of rodlike polyelectrolytes.

We calculate the relaxation, rise, and frequency dependence of the parallel polarization of counterions condensed on rodlike polyelectrolytes and charged colloids. Emphasis is placed on an effective counterion mobility along the rod as strongly influenced by electrostatic interactions.

Assessment of lower limb microcirculation: exploring the reproducibility and clinical application of laser Doppler techniques.

PURPOSE OF STUDY: Non-invasive laser Doppler fluximetry (LDF) and laser Doppler imaging (LDI), combined with iontophoresis, have been used to study the microcirculation in a range of clinical conditions including lower limb venous disease. A prerequisite for an accurate measurement tool is that it is reproducible. However, there is currently no literature with respect to the reproducibility of LDF and LDI combined with iontophoresis in the lower limb (in general) and in the upright position (in specific). Furthermore, the two techniques have been used interchangeably by researchers and the association between these two different measurement methods has not been explored, nor have the factors that affect them been well described. Thus the aim of this study was to determine the reproducibility of LDF and LDI with iontophoresis in the lower limb and investigate factors that influence their clinical application. PROCEDURES: Cutaneous microvascular responses in the lower limb were measured in the supine and standing positions using LDF and LDI combined with iontophoretic administration of endothelial-dependent (acetylcholine, ACh) and -independent (sodium nitroprusside) vasodilators in 25 patients with uncomplicated isolated superficial venous incompetence (ISVI) and 26 healthy controls. RESULTS: Maximum perfusion had the best reproducibility assessed by LDF (CV 20.5-24.3%) and LDI (15.8-17.6%). Both techniques were positively influenced by iontophoretic dose (e.g. p = 0.0001 for LDF) and the use of vasodilator agents (e.g. p = 0.0001 for LDF), but negatively influenced in the standing position and/or in the presence of ISVI (p = 0.0016 and 0.045, respectively, for LDF). There was a statistically significant positive relationship between the two techniques, for example ACh maximum perfusion versus LDF ACh maximum perfusion (r = 0.404, p = 0.016). CONCLUSIONS: Both techniques are reproducible, in line with similar studies undertaken in other areas of the human body, and provide useful information for the study of the lower-limb microcirculation. Direct comparison between techniques based on absolute numbers should be avoided and the technique choice should be based on individual study needs.

Management of tracheostomy-related tracheomegaly in a patient with COVID-19 pneumonitis.

Acquired tracheomegaly is a rare condition associated with pulmonary fibrosis, connective tissue disease and the use of cuffed tracheal tubes. We describe the urgent tracheal re-intubation and subsequent tracheal repair of a previously well 58-year-old man who developed tracheostomy-related tracheomegaly during prolonged mechanical ventilation for coronavirus disease 2019 pneumonitis. Urgent tracheal re-intubation was required due to a persistent cuff leak, pneumomediastinum and malposition of the tracheostomy tube. We describe the additional challenges and risks associated with airway management in patients with tracheomegaly, and discuss how even in urgent cases these can be mitigated through planning and teamwork. We present a stepwise approach to tracheal re-intubation past a large tracheal dilatation, including the use of an Aintree catheter inserted via the existing tracheal stoma for oxygenation or tracheal re-intubation if required. Computed tomography imaging was valuable in characterising the defect and developing a safe airway management strategy before starting the procedure. This report emphasises the role of planning, teamwork and the development of an appropriate airway strategy in the safe management of complex cases.

Whole animal cell sorting of Drosophila embryos.

Use of primary culture cells has been limited by the inability to purify most types of cells, particularly cells from early developmental stages. In whole animal cell sorting (WACS), live cells derived from animals harboring a lacZ transgene are purified according to their level of beta-galactosidase expression with a fluorogenic beta-galactosidase substrate and fluorescence-activated cell sorting. With WACS, incipient posterior compartment cells that express the engrailed gene were purified from early Drosophila embryos. Neuronal precursor cells were also purified, and they differentiated into neurons with high efficiency in culture. Because there are many lacZ strains, it may be possible to purify most types of Drosophila cells. The same approach is also applicable to other organisms for which germ-line transformation is possible.

Transverse polarizability of an aligned assembly of charged rods.

The low-field transverse polarizability of the counterions condensed on an isolated charged rod is small. We show that it can be much larger if the rod is a member of an assembly of aligned rods. The polarization free energy of the assembly of rods in a transverse field is then similar to its polarization free energy in a field parallel to the rods. The polarization free energy of the assembly in a transverse field becomes lower than in a parallel field if the extent of the assembly (as measured, for example, by the diameter of a cylindrical assembly) is larger than the length of the individual rods. We suggest that this model may provide a reasonable explanation for the occurrence of "anomalous" birefringence in systems of interacting charged rodlike particles.

Examining Radiation-Induced In Vivo and In Vitro Gene Expression Changes of the Peripheral Blood in Different Laboratories for Biodosimetry Purposes: First RENEB Gene Expression Study.

The risk of a large-scale event leading to acute radiation exposure necessitates the development of high-throughput methods for providing rapid individual dose estimates. Our work addresses three goals, which align with the directive of the European Union's Realizing the European Network of Biodosimetry project (EU-RENB): 1. To examine the suitability of different gene expression platforms for biodosimetry purposes; 2. To perform this examination using blood samples collected from prostate cancer patients (in vivo) and from healthy donors (in vitro); and 3. To compare radiation-induced gene expression changes of the in vivo with in vitro blood samples. For the in vitro part of this study, EDTA-treated whole blood was irradiated immediately after venipuncture using single X-ray doses (1 Gy/min(-1) dose rate, 100 keV). Blood samples used to generate calibration curves as well as 10 coded (blinded) samples (0-4 Gy dose range) were incubated for 24 h in vitro, lysed and shipped on wet ice. For the in vivo part of the study PAXgene tubes were used and peripheral blood (2.5 ml) was collected from prostate cancer patients before and 24 h after the first fractionated 2 Gy dose of localized radiotherapy to the pelvis [linear accelerator (LINAC), 580 MU/min, exposure 1-1.5 min]. Assays were run in each laboratory according to locally established protocols using either microarray platforms (2 laboratories) or qRT-PCR (2 laboratories). Report times on dose estimates were documented. The mean absolute difference of estimated doses relative to the true doses (Gy) were calculated. Doses were also merged into binary categories reflecting aspects of clinical/diagnostic relevance. For the in vitro part of the study, the earliest report time on dose estimates was 7 h for qRT-PCR and 35 h for microarrays. Methodological variance of gene expression measurements (CV ≤10% for technical replicates) and interindividual variance (≤twofold for all genes) were low. Dose estimates based on one gene, ferredoxin reductase (FDXR), using qRT-PCR were as precise as dose estimates based on multiple genes using microarrays, but the precision decreased at doses ≥2 Gy. Binary dose categories comprising, for example, unexposed compared with exposed samples, could be completely discriminated with most of our methods. Exposed prostate cancer blood samples (n = 4) could be completely discriminated from unexposed blood samples (n = 4, P < 0.03, two-sided Fisher's exact test) without individual controls. This could be performed by introducing an in vitro-to-in vivo correction factor of FDXR, which varied among the laboratories. After that the in vitro-constructed calibration curves could be used for dose estimation of the in vivo exposed prostate cancer blood samples within an accuracy window of ±0.5 Gy in both contributing qRT-PCR laboratories. In conclusion, early and precise dose estimates can be performed, in particular at doses ≤2 Gy in vitro. Blood samples of prostate cancer patients exposed to 0.09-0.017 Gy could be completely discriminated from pre-exposure blood samples with the doses successfully estimated using adjusted in vitro-constructed calibration curves.

A theory of DNA dissociation from the nucleosome.

Previous analysis of an elastic model of the nucleosome indicated that 10 bp end segments of DNA can exist in a continuum of mechanically stable trajectories ranging from complete winding on the histone octamer to complete unwinding. Stable states of 20 bp and 40 bp end segments, however, are grouped in bands separated by gaps where DNA trajectories are unstable. We extend these results to cover the entire range up to a complete nucleosomal turn, 80 bp. We find that 10 to 60 bp segments have states intermediate between fully wound and fully unwound that are mechanically stable. In striking contrast, there is no stable intermediate trajectory for 70 bp or 80 bp segments. Segments of these lengths constitute a two-state system. A 70 or 80 bp segment is either fully wound or fully unwound, and the population of these states is governed by Boltzmann's thermal distribution. We have found a plausible dissociation pathway from the fully wound to the fully unwound state for the 80 bp segment. In a ponderous breathing motion that breaks all contacts with the histone ponderous breathing motion that breaks all contacts with the histone surface, the segment climbs to an activation peak of about 12 kcal/mol, then rapidly straightens away from the histone core to complete dissociation.

Counterion association with native and denatured nucleic acids: an experimental approach.

The melting temperature of the poly(dA) . poly(dT) double helix is exquisitely sensitive to salt concentration, and the helix-to-coil transition is sharp. Modern calorimetric instrumentation allows this transition to be detected and characterized with high precision at extremely low duplex concentrations. We have taken advantage of these properties to show that this duplex can be used as a sensitive probe to detect and to characterize the influence of other solutes on solution properties. We demonstrate how the temperature associated with poly(dA) . poly(dT) melting can be used to define the change in bulk solution cation concentration imparted by the presence of other duplex and triplex solutes, in both their native and denatured states. We use this information to critically evaluate features of counterion condensation theory, as well as to illustrate "crosstalk" between different, non-contacting solute molecules. Specifically, we probe the melting of a synthetic homopolymer, poly(dA) . poly(dT), in the presence of excess genomic salmon sperm DNA, or in the presence of one of two synthetic RNA polymers (the poly(rA) . poly(rU) duplex or the poly(rU) . poly(rA) . poly(rU) triplex). We find that these additions cause a shift in the melting temperature of poly(dA) . poly(dT), which is proportional to the concentration of the added polymer and dependent on its conformational state (B versus A, native versus denatured, and triplex versus duplex). To a first approximation, the magnitude of the observed tm shift does not depend significantly on whether the added polymer is RNA or DNA, but it does depend on the number of strands making up the helix of the added polymer. We ascribe the observed changes in melting temperature of poly(dA) . poly(dT) to the increase in ionic strength of the bulk solution brought about by the presence of the added nucleic acid and its associated counterions. We refer to this communication between non-contacting biopolymers in solution as solvent-mediated crosstalk. By comparison with a known standard curve of tm versus log[Na+] for poly(dA) . poly(dT), we estimate the magnitude of the apparent change in ionic strength resulting from the presence of the bulk nucleic acid, and we compare these results with predictions from theory. We find that current theoretical considerations correctly predict the direction of the t(m) shift (the melting temperature increases), while overestimating its magnitude. Specifically, we observe an apparent increase in ionic strength equal to 5% of the concentration of the added duplex DNA or RNA (in mol phosphate), and an additional apparent increase of about 9.5 % of the nucleic acid concentration (mol phosphate) upon denaturation of the added DNA or RNA, yielding a total apparent increase of 14.5 %. For the poly(rU) . poly(rA) . poly(rU) triplex, the total apparent increase in ionic strength corresponds to about 13.6% of the amount of added triplex (moles phosphate). The effect we observe is due to coupled equilibria between the solute molecules mediated by modulations in cation concentration induced by the presence and/or the transition of one of the solute molecules. We note that our results are general, so one can use a different solute probe sensitive to proton binding to characterize subtle changes in solution pH induced by the presence of another solute in solution. We discuss some of the broader implications of these measurements/results in terms of nucleic acid melting in multicomponent systems, in terms of probing counterion environments, and in terms of potential regulatory mechanisms.

Multiple endocrine neoplasia, type I. Association with marfanoid habitus, optic atrophy, and other abnormalities.

A patient had a parathyroid adenoma and prolactin-secreting pituitary tumor, suggestive of the multiple endocrine neoplasia (MEN) I syndrome. The presence of a marfanoid habitus--found more typically in MEN III syndrome--as well as mitral valve prolapse, mental retardation, and bilateral optic atrophy suggests a new variant of the MEN syndrome, possibly representing widespread dysplasia of endocrine and other tissues.

Time, dose and ataxia telangiectasia mutated (ATM) status dependency of coding and noncoding RNA expression after ionizing radiation exposure.

Studies of gene expression have proved important in defining the molecular mechanisms of radiation action and identifying biomarkers of ionizing radiation exposure and susceptibility. The full transcriptional response to radiation is very complex since it also involves epigenetic mechanisms triggered by radiation exposure such as modifications of expression of noncoding RNA such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) that have not been fully characterized. To improve our understanding of the transcriptional response to radiation, we simultaneously monitored the expression of ten protein-coding genes, as well as 19 miRNAs and 3 lncRNAs in a time- and dose-dependent manner in stimulated human T lymphocytes obtained from two healthy donors (C1 and C2) and one patient with ataxia telangiectasia (AT), which is a well characterized radiosensitivity disorder. After 2 Gy X irradiation, expression levels were monitored at time points ranging from 15 min up to 24 h postirradiation. The majority of genes investigated responded rapidly to radiation exposure, with the peak up-regulation (CDKN1A, SESN1, ATF3, MDM2, PUMA and GADD45A) or down-regulation (CCNB1) occurring 2-3 h postirradiation, while DDB2, FDXR and CCNG1 responded with slower kinetics reaching a peak of expression between 5 and 24 h. A significant modification of expression after radiation exposure was observed for miR-34a-5p and miR-182-5p, with an up-regulation occurring at late time points reaching two to threefold at 24 h. Differences between two donors in miR-182-5p response to radiation were detected: for C2, up-regulation reached a plateau-phase around 5 Gy, while for C1, up-regulation was at its maximum around 3 Gy and then decreased at higher doses. Among the three lncRNAs studied, TP53TG1 demonstrated a weak up-regulation, reaching a maximum of 1.5-fold at 24 h after radiation exposure. Conversely, FAS-AS1 was up-regulated up to fivefold by 5 Gy irradiation. Our results indicate that expression of the majority of protein-coding genes allows discrimination of the AT from healthy donors when analyzed at 2 h. However, differences in expression between AT and healthy donors are no longer detectable 24 h postirradiation although, interestingly, linear dose responses for some of the genes studied are obtained at this time point. Furthermore, our study shows that miRNAs miR-34a-5p and miR-182-5p are responsive to radiation exposure in a dose- and time-dependent manner. Additionally, to the best of our knowledge, this is the first study to report that FAS-AS1 lncRNA is up-regulated by radiation exposure in an ATM-dependent fashion in human T lymphocytes.

Effect of diabetes on the cutaneous microcirculation of the feet in patients with intermittent claudication.

AIMS: To evaluate endothelial-dependent and - independent cutaneous vasodilator responses in the feet of patients with peripheral arterial disease (PAD) with or without Type 2 diabetes. METHODS: Cutaneous microvascular responses in the dorsum of both lower limbs were measured in the supine position using Laser Doppler Fluximetry combined with iontophoretic administration of endothelial-dependent (acetylcholine, Ach) and -independent (sodium nitroprusside, SNP) vasodilators in diabetic (n = 19) and non diabetic (n = 17) patients with PAD (presenting as unilateral calf intermittent claudication (IC). RESULTS: In patients with diabetes and IC, endothelial-dependent vasodilation was significantly impaired in the symptomatic limb [74 (57,105) vs 68 (24,81) PU, Z =-2.79, p = 0.005] compared to the asymptomatic limb. Patients without diabetes showed no impairment of vasodilation. Resting ankle-brachial pressure index did not identify the presence of abnormalities in microvascular function. CONCLUSIONS: The combination of diabetes and PAD is associated with a reduction in endothelial-dependent cutaneous vasodilation in the feet without an associated reduction in endothelial independent vasodilation.

Management of massive hemoptysis secondary to catheter-induced perforation of the pulmonary artery during cardiopulmonary bypass.

Pulmonary artery perforation by flow-directed catheters is associated with high mortality, particularly in heparinized patients. We report a recent case and discuss recognition and management.

Variability of diurnal changes in ambulatory blood pressure and nocturnal dipping status in untreated hypertensive and normotensive subjects.

An absent or diminished blood pressure (BP) fall during sleep (so-called "nondipping") has been associated with a higher risk of cardiovascular complications, but the long-term reproducibility of dipper status and the relationship between diurnal changes in BP and perceived sleep quality have not been previously documented in untreated hypertensive patients. Ambulatory BP (ABP) and dipping status were examined in 79 subjects (69 hypertensives and 10 normotensives) at 0, 6, and 12 months. Fifty-six percent of subjects had no change in their dipping status, the majority (53%) dipping normally on all three occasions. However, 44% of patients had variable dipping status, and normal nighttime dipping in BP was observed more often when patients perceived their sleep quality to be good during the period of ABP recording. These results highlight significant intrasubject variability in the diurnal fluctuations in ABP and dipper status, which may in part reflect day-to-day variations in sleep disturbance during ABP monitoring. Classifying hypertensive patients into dippers or nondippers on the basis of a single ABP recording is unreliable and potentially misleading.

The relation between osmotic flow and tracer solvent diffusion for single-file transport.

It is demonstrated that a reasonably general model for single-file passage of solvent through an ultra-narrow pore implies the equality of tracer diffusion and osmotic flow. This result is not trival, but follows from the exactly compensating effects of solvent-solvent interaction on the paritioning of bulk solvent into the pore and on the diffusion rate within the pore. A previous calculation of Longuet-Higgins and Austin is seen to be valid only in the absence of interactions among solvent molecules in the pore.

A field-dissociation relation for polyelectrolytes with an application to field-induced conformational changes of polynucleotides.

An extension to polyelectrolyte solutions of Onsager's field-dissociation relation for weak electrolytes can be derived in a simple way. It is found that, except in the limit of zero ionic strength, a strong applied electric field prevents counterion condensation from proceeding to completion. The extent of incompleteness initially varies linearly with the applied field. The field-dissociation relation can easily be incorporated into the theory of ionic effects on the stability of ordered polynucleotide structures, whereupon a dependence of the stability on field strength emerges. An explicit calculation for a co-operative transition of the DNA melting type is presented, and it is concluded that for sufficiently low ionic strengths, a field of the order of 10 kV/cm may be able to induce melting by lowering the Tm by a few degrees. The threshold effect found experimentally by Pörschke, and particularly the observed linear dependence of the threshold field on the logarithm of the ionic strength, appears here as a simple consequence of the linear increase of the stabilization free energy with the logarithm of ionic strength.