Kudoa hypoepicardialis and associated cardiac lesions in invasive red lionfish Pterois volitans in Grenada, West Indies.

Invasive red lionfish Pterois volitans (Linnaeus, 1758) represent an ongoing ecological threat within temperate and tropical waters. Relatively little is known regarding the overall health of P. volitans and their potential for spreading pathogens in non-native regions. Lionfish collected from inshore reefs of Grenada, West Indies, in 2019 and 2021 were identified as P. volitans based on cytochrome c oxidase subunit 1 barcoding. Gross and microscopic examination of tissues revealed myxozoan plasmodia in the hearts of 24/76 (31.6%) lionfish by histopathology or wet mount cytology. Further histopathologic examination revealed severe granulomatous inflammation and myofiber necrosis associated with developing plasmodia and presporogonic life stages. Fresh myxospores were morphologically and molecularly consistent with Kudoa hypoepicardialis, being quadrate in apical view with 4 valves and 4 equal polar capsules. The spore body was 5.1-7.9 (mean: 6.0) µm long, 8.1-9.8 (8.7) µm wide, and 6.9-8.5 (7.7) µm thick. Polar capsules were 2.3-2.7 (2.5) µm long and 0.9-1.6 (1.3) µm wide. 18S small subunit rDNA sequences were 99.81-99.87% similar to sequence data from the original description of the species. Novel 28S large subunit rDNA and elongation factor 2 data, which did not match any previously reported species, were provided. This is the first account of a myxozoan parasite of P. volitans, a new host record and locality for K. hypoepicardialis, and one of few reports describing pathogen-associated lesions in invasive lionfish.

The structure of aqueous solutions of hexafluoro-iso-propanol studied by neutron diffraction with hydrogen/deuterium isotope substitution and empirical potential structure refinement modeling.

Neutron diffraction measurements of H/D isotopic substitution are made at room temperature for seven H/D substituted hexafluoro-iso-propanol (HFIP; 1,1,1,3,3,3-hexafluoro-2-propanol)-water mixtures at 0.1, 0.2, and 0.4 HFIP mole fraction (xHFIP). The eight partial structure factors except for the H(CH)-H(CH) pair obtained are subjected to an empirical potential structure refinement (EPSR) method to derive all site-site pair correlation functions. It is found that with increasing HFIP concentration the ice-like network of water disappears between xHFIP = 0.1 and 0.2, followed by the formation of a chain-like water structure embedded in an intrinsic structure of HFIP evolved at xHFIP = 0.4. The hydroxyl group of HFIP forms hydrogen bonds with the surrounding water molecules at all HFIP mole fractions investigated. There is no evidence that the water structure is well defined around the CF3 groups of HFIP, but water molecules surround tangentially the CF3 groups of HFIP.

Influence of Patient Choice on Outcome of Bariatric Surgery.

BACKGROUND: The "perfect" bariatric procedure remains the topic of debate. The aim of this study is to compare the safety and outcome of laparoscopic Roux-en-Y gastric bypass (LRYGB) to those of laparoscopic sleeve gastrectomy (LSG) and adjustable gastric band (AGB) in a single centre, amongst those patients who made their own choice of which procedure they prefer. METHODS: After the multi-disciplinary team's assessment, the patients could make their own choice of procedures (self-selected, SS), unless medical/surgical conditions limited this (medically restricted, MR). All consecutive primary bariatric procedures were involved and reviewed between June 2010 and September 2014. The primary outcomes included 30-day complication and readmission rates, excess weight loss (%EWL) and co-morbidity resolution at 24 months postoperatively. RESULTS: A total of 303 patients were included and 271 of them made their own choice (SS 90%). One hundred eighty-three chose LRYGB (60.4%), and 57 underwent LSG (SS 45 and MR 12; overall 18.8%), with the initial BMI of 50.7 and 52.5 kg/m2, respectively. Sixty-two patients (SS 43, MR 19, overall 20%) underwent AGB, with a BMI of 52.1 kg/m2. Thirty-day complication rates for LRYGB and LSG were 10.2 and 2.9% (p < 0.05), and the readmission rates were 4.7 and 2.9%, respectively. %EWL for LRYGB was significantly higher than that of other procedures at 24 months (67.8 vs SS-sleeve 43.9%, MR-sleeve 47%, SS-band 33.8% and MR-band 36%; FU rate 94%). Diabetes remission was achieved in 31/50 patients in the LRYGB group (62%) and 2/9 patients (22%) in the LSG group. CONCLUSIONS: Self-selected bariatric procedures yield excellent weight loss and metabolic outcome. Providing an information-dense environment augments the choice of the right operation and could improve patients' compliance with weight loss surgery programmes.

High-dose therapy and autologous stem cell transplant in older adults with multiple myeloma.

Randomized trials showing that high-dose therapy with autologous stem cell transplant (ASCT) improved the overall survival (OS) in multiple myeloma (MM) excluded patients over age 65. To compare the outcomes of older adults with MM who underwent ASCT with non-transplant strategies, we identified 146 patients aged 65-77 with newly diagnosed MM seen in the Washington University School of Medicine from 2000 to 2010. Survival among patients who did (N=62) versus did not (N=84) undergo ASCT was compared using Cox proportional hazards modeling, controlling for comorbidities, Eastern Cooperative Oncology Group performance status (PS) and the propensity to undergo ASCT. Median age was 68 years (range 65-77). PS and comorbidities did not differ significantly between those who did versus those who did not undergo ASCT. Median OS was significantly longer in patients who underwent ASCT than in those who did not (median 56.0 months (95% confidence intervals (CIs) 49.1-65.4) versus 33.1 months (24.3-43.1), P=0.004). Adjusting for PS, comorbidities, Durie-Salmon stage and the propensity to undergo ASCT, ASCT was associated with superior OS (HR for mortality 0.52 (95% CI 0.30-0.91), P=0.02). In a cohort of older adults with MM, undergoing ASCT was associated with a nearly 50% lower mortality, after controlling for PS, comorbidities, stage and the propensity to undergo ASCT.

Prediction of Staphylococcus aureus antimicrobial resistance by whole-genome sequencing.

Whole-genome sequencing (WGS) could potentially provide a single platform for extracting all the information required to predict an organism's phenotype. However, its ability to provide accurate predictions has not yet been demonstrated in large independent studies of specific organisms. In this study, we aimed to develop a genotypic prediction method for antimicrobial susceptibilities. The whole genomes of 501 unrelated Staphylococcus aureus isolates were sequenced, and the assembled genomes were interrogated using BLASTn for a panel of known resistance determinants (chromosomal mutations and genes carried on plasmids). Results were compared with phenotypic susceptibility testing for 12 commonly used antimicrobial agents (penicillin, methicillin, erythromycin, clindamycin, tetracycline, ciprofloxacin, vancomycin, trimethoprim, gentamicin, fusidic acid, rifampin, and mupirocin) performed by the routine clinical laboratory. We investigated discrepancies by repeat susceptibility testing and manual inspection of the sequences and used this information to optimize the resistance determinant panel and BLASTn algorithm. We then tested performance of the optimized tool in an independent validation set of 491 unrelated isolates, with phenotypic results obtained in duplicate by automated broth dilution (BD Phoenix) and disc diffusion. In the validation set, the overall sensitivity and specificity of the genomic prediction method were 0.97 (95% confidence interval [95% CI], 0.95 to 0.98) and 0.99 (95% CI, 0.99 to 1), respectively, compared to standard susceptibility testing methods. The very major error rate was 0.5%, and the major error rate was 0.7%. WGS was as sensitive and specific as routine antimicrobial susceptibility testing methods. WGS is a promising alternative to culture methods for resistance prediction in S. aureus and ultimately other major bacterial pathogens.

Ion interactions with non-polar and amphiphilic solutes in water.

Despite its extensive use in, for example, the concentration and crystallization of proteins, the salting out phenomenon remains poorly understood, with many--sometimes contradictory--explanations found in the literature. Following our earlier work using isotope substitution neutron scattering on an aqueous tertiary butyl alcohol (TBA) with added NaCl that examined in detail the molecular-level interactions in the system, and suggested that attempts to understand salting out through ion perturbation of the non-polar hydration shell may not be appropriate, we report here on two further sets of high resolution structural experiments that detail the structural interactions between ion, solvent and amphiphile in a wider range of relevant systems. First, a set of X-ray absorption spectroscopy experiments probed the effects on the hydrophobic hydration shell of Kr of adding a range of different salts (specifically Na2SO4, NaClO4, NaCl, NaNO3 and Mg(ClO4)2). The bottom line from these experiments is that the hydration shell is essentially unaffected by the added ions, underlining further the stability of the shell to such perturbations. The second set of experiments was a further isotope substitution neutron scattering study of the molecular-level solution structures of aqueous TBA, this time for a range of different added ions (CsF, NaBr, and NaCl at three concentrations), for which we have in addition extracted equilibrium constants to quantify the relative strengths of the various interactions. From this second set of results, we can conclude again that the solvent structure is essentially unperturbed by both the various ions and the amphiphile, and also identify a number of ion-specific effects. Comparing our results with those obtained from simulations that are not constrained by the experimental data underlines how sensitive structural conclusions are to the assumed potential functions, and that drawing conclusions from simulations not constrained to fit experimental data can lead to seriously erroneous conclusions.

The relationship between solution structure and crystal nucleation: a neutron scattering study of supersaturated methanolic solutions of benzoic acid.

In this contribution, neutron scattering experiments (with isotopic substitution) of concentrated and supersaturated methanolic benzoic acid solutions combined with empirical potential structure refinement (EPSR) were used to investigate the time-averaged atomistic details of this system. Through the determination of radial distribution functions, quantitative details emerge of the solution coordination, its relationship to the nature of the crystalline phase, and the response of the solution to imposed supersaturation.

The relative significance of host-habitat, depth, and geography on the ecology, endemism, and speciation of coral endosymbionts in the genus Symbiodinium.

Dinoflagellates in the genus Symbiodinium are among the most abundant and important group of eukaryotic microbes found in coral reef ecosystems. Recent analyses conducted on various host cnidarians indicated that Symbiodinium assemblages in the Caribbean Sea are genetically and ecologically diverse. In order to further characterize this diversity and identify processes important to its origins, samples from six orders of Cnidaria comprising 45 genera were collected from reef habitats around Barbados (eastern Caribbean) and from the Mesoamerican barrier reef off the coast of Belize (western Caribbean). Fingerprinting of the ribosomal internal transcribed spacer 2 identified 62 genetically different Symbiodinium. Additional analyses of clade B Symbiodinium using microsatellite flanker sequences unequivocally characterized divergent lineages, or "species," within what was previously thought to be a single entity (B1 or B184). In contrast to the Indo-Pacific where host-generalist symbionts dominate many coral communities, partner specificity in the Caribbean is relatively high and is influenced little by the host's apparent mode of symbiont acquisition. Habitat depth (ambient light) and geographic isolation appeared to influence the bathymetric zonation and regional distribution for most of the Symbiodinium spp. characterized. Approximately 80% of Symbiodinium types were endemic to either the eastern or western Caribbean and 40-50% were distributed to compatible hosts living in shallow, high-irradiance, or deep, low-irradiance environments. These ecologic, geographic, and phylogenetic patterns indicate that most of the present Symbiodinium diversity probably originated from adaptive radiations driven by ecological specialization in separate Caribbean regions during the Pliocene and Pleistocene periods.

Relaxation effects in low density amorphous ice: two distinct structural states observed by neutron diffraction.

Neutron diffraction with H/D isotopic substitution is used to investigate the structure of low density amorphous ice produced from (1) high density amorphous ice by isobaric warming and (2) very high density amorphous ice by isothermal decompression. Differences are found in the scattering patterns of the two low density amorphous ices that correlate with structural perturbations on intermediate length scales in the hydrogen bonded water network. Atomistic modeling suggests that the structural states of the two samples may relate to a competition between short range and intermediate range order and disorder. This structural difference in two low density amorphous (LDA) ices is also evident when comparing their compression behavior. In terms of the energy landscape formalism this finding implies that we have produced and characterized the structural difference of two different basins within the LDA-megabasin corresponding to identical macroscopic densities.

Relationship between solution structure and phase behavior: a neutron scattering study of concentrated aqueous hexamethylenetetramine solutions.

The water-hexamethylenetetramine system displays features of significant interest in the context of phase equilibria in molecular materials. First, it is possible to crystallize two solid phases depending on temperature, both hexahydrate and anhydrous forms. Second, saturated aqueous solutions in equilibrium with these forms exhibit a negative dependence of solubility (retrograde) on temperature. In this contribution, neutron scattering experiments (with isotopic substitution) of concentrated aqueous hexamethylenetetramine solutions combined with empirical potential structure refinement (EPSR) were used to investigate the time-averaged atomistic details of this system. Through the derivation of radial distribution functions, quantitative details emerge of the solution coordination, its relationship to the nature of the solid phases, and of the underlying cause of the solubility behavior of this molecule.

Association and dissociation of an aqueous amphiphile at elevated temperatures.

The hydrophobic interaction is often thought to increase with increasing temperature. Although there is good experimental evidence for decreased aqueous solubility and increased clustering of both nonpolar and amphiphilic molecules as temperature is increased, the detailed nature of the changes in intermolecular interactions with temperature remain unknown. By use of isotope substitution neutron scattering difference measurements on a 0.04 mole fraction solution of tert-butanol in water as the solute clustering passes through a temperature maximum, the changes in local intermolecular structures are examined. Although, as expected, the solute molecules cluster through increased contact between their nonpolar head groups with the exclusion of water, the detailed geometry of the mutual interactions changes as temperature increases. As the clustering breaks up with further temperature increase, the local structures formed do not mirror those that were found in the low-temperature dispersed system: the disassembly process is not the reverse of assembly. The clusters formed by the solute head groups are reminiscent of structures that are found in systems of spherical molecules, modulated by the additional constraint of near-maximal hydrogen bonding between the polar tails of the alcohol and the solvent water. Although the overall temperature behavior is qualitatively what would be expected of a hydrophobically driven system, the way the system resolves the competing interactions and their different temperature dependencies is complex, suggesting it could be misleading to think of the aggregation of aqueous amphiphiles solely in terms of a hydrophobic driving force.

The local and intermediate range structures of the five amorphous ices at 80 K and ambient pressure: a Faber-Ziman and Bhatia-Thornton analysis.

Using isotope substitution neutron scattering data, we present a detailed structural analysis of the short and intermediate range structures of the five known forms of amorphous ice. Two of the lower density forms--amorphous solid water and hyperquenched glassy water--have a structure very similar to each other and to low density amorphous ice, a structure which closely resembles a disordered, tetrahedrally coordinated, fully hydrogen bonded network. High density and very high density amorphous ices retain this tetrahedral organization at short range, but show significant differences beyond about 3.1 A from a typical water oxygen. The first diffraction peak in all structures is seen to be solely a function of the intermolecular organization. The short range connectivity in the two higher density forms is more homogeneous, while the hydrogen site disorder in these forms is greater. The low Q behavior of the structure factors indicates no significant density or concentration fluctuations over the length scale probed. We conclude that these three latter forms of ice are structurally distinct. Finally, the x-ray structure factors for all five amorphous systems are calculated for comparison with other studies.

Wild rabbits (Oryctolagus cuniculus) as potential carriers of verocytotoxin-producing Escherichia coli.

In summer 2001, visitors to a wildlife park in Norfolk, uk, became infected with verocytotoxin-producing Escherichia coli (vtec) O157, which was associated with wild rabbit faeces. The rabbits lived in an adjacent field together with E coli O157-positive cattle. A pilot study was therefore performed to investigate the factors affecting the association between E coli O157-positive cattle and wild rabbits. Samples of faeces were taken from 16 herds of cattle that lived close to populations of wild rabbits. Analysis by culture and pcr showed that seven of the herds were positive for E coli O157. Faeces were collected from individual rabbits at six of these farms during late winter, when there were few rabbits, and during high summer, when there were many. None of the 32 samples collected on two farms in late winter was positive for E coli O157, but eight of 97 samples collected in summer were positive on four of the six farms. pcr analysis for vtec, including non-O157, showed that 20 of the 97 samples were positive.

The hydration of the neurotransmitter acetylcholine in aqueous solution.

Neutron diffraction augmented with hydrogen isotope substitution has been used to examine the water structure around the acetylcholine molecular ion in aqueous solution. It is shown that the nearest-neighbor water molecules in the region around the trimethylammonium headgroup are located either in a ring around the central nitrogen atom or between the carbon atoms, forming a sheath around the onium group. Moreover the water molecules in this cavity do not bond to the onium group but rather form hydrogen bonds with water molecules in the surrounding aqueous environment. Given that in the bound state the onium headgroup must be completely desolvated, the absence of bonding between the onium headgroup and the surrounding water solvent may be selectively favorable to acetylcholine-binding in the receptor site. Away from the headgroup, pronounced hydrogen-bonding of water to the carbonyl oxygen is observed, but not to the ether oxygen in the acetylcholine chain.

Magnetic versus manual guidewire manipulation in neuroradiology: in vitro results.

INTRODUCTION: Standard microguidewires used in interventional neuroradiology have a predefined shape of the tip that cannot be changed while the guidewire is in the vessel. We evaluated a novel magnetic navigation system (MNS) that generates a magnetic field to control the deflection of a microguidewire that can be used to reshape the guidewire tip in vivo without removing the wire from the body, thereby potentially facilitating navigation along tortuous paths or multiple acute curves. METHOD: The MNS consists of two permanent magnets positioned on either side of the fluoroscopy table that create a constant precisely controlled magnetic field in the defined region of interest. This field enables omnidirectional rotation of a 0.014-inch magnetic microguidewire (MG). Speed of navigation, accuracy in a tortuous vessel anatomy and the potential for navigating into in vitro aneurysms were tested by four investigators with differing experience in neurointervention and compared to navigation with a standard, manually controlled microguidewire (SG). RESULTS: Navigation using MG was faster (P=0.0056) and more accurate (0.2 mistakes per trial vs. 2.6 mistakes per trial) only in less-experienced investigators. There were no statistically significant differences between the MG and the SG in the hands of experienced investigators. One aneurysm with an acute angulation from the carrier vessel could be navigated only with the MG while the SG failed, even after multiple reshaping manoeuvres. CONCLUSION: Our findings suggest that magnetic navigation seems to be easier, more accurate and faster in the hands of less-experienced investigators. We consider that the features of the MNS may improve the efficacy and safety of challenging neurointerventional procedures.

Dynamics of immobilized and native Escherichia coli dihydrofolate reductase by quasielastic neutron scattering.

The internal dynamics of native and immobilized Escherichia coli dihydrofolate reductase (DHFR) have been examined using incoherent quasielastic neutron scattering. These results reveal no difference between the high frequency vibration mean-square displacement of the native and the immobilized E. coli DHFR. However, length-scale-dependent, picosecond dynamical changes are found. On longer length scales, the dynamics are comparable for both DHFR samples. On shorter length scales, the dynamics is dominated by local jump motions over potential barriers. The residence time for the protons to stay in a potential well is tau = 7.95 +/- 1.02 ps for the native DHFR and tau = 20.36 +/- 1.80 ps for the immobilized DHFR. The average height of the potential barrier to the local motions is increased in the immobilized DHFR, and may increase the activation energy for the activity reaction, decreasing the rate as observed experimentally. These results suggest that the local motions on the picosecond timescale may act as a lubricant for those associated with DHFR activity occurring on a slower millisecond timescale. Experiments indicate a significantly slower catalytic reaction rate for the immobilized E. coli DHFR. However, the immobilization of the DHFR is on the exterior of the enzyme and essentially distal to the active site, thus this phenomenon has broad implications for the action of drugs distal to the active site.

Segregation in aqueous methanol enhanced by cooling and compression.

Molecular segregation in methanol-water mixtures is studied across a wide concentration range as a function of temperature and pressure. Cluster distributions obtained from both neutron diffraction and molecular dynamics simulations point to significantly enhanced segregation as the mixtures are cooled or compressed. This evolution toward greater molecular heterogenity in the mixture accounts for the observed changes in the water-water radial distribution function and there are indications also of a change in the topology of the water clusters. The observed behavior is consistent with an approach to an upper critical solution point. Such a point would appear to be "hidden" below the freezing line, thereby precluding observation of the two-fluid region.

Methanol-water solutions: a bi-percolating liquid mixture.

An extensive series of neutron diffraction experiments and molecular dynamics simulations has shown that mixtures of methanol and water exhibit extended structures in solution despite the components being fully miscible in all proportions. Of particular interest is a concentration region (methanol mole fraction between 0.27 and 0.54) where both methanol and water appear to form separate, percolating networks. This is the concentration range where many transport properties and thermodynamic excess functions reach extremal values. The observed concentration dependence of several of these material properties of the solution may therefore have a structural origin.

Molecular and mesoscale structures in hydrophobically driven aqueous solutions.

Since Kauzmann's seminal 1959 paper, the hydrophobic interaction has dominated thinking on the forces that control protein folding and stability. Despite its wide importance in chemistry and biology, our understanding of this interaction at the molecular level remains poor, with little experimental evidence to support the idea of water ordering close to a non-polar group that is at the centre of the standard model for the source of the entropic driving force. Developments over recent years in neutron techniques now enable us to see directly how a non-polar group actually affects the molecular structure of the water in its immediate neighbourhood. On the basis of such work on aqueous solutions of small alcohols, the generally accepted standard model is found to be wanting, and alternative sources of the entropic driving force are suggested. Moreover, the fact that we can now follow changes in hydrogen bonding as the alcohol concentration is varied gives us the possibility of explaining the concentration dependence of the enthalpy of mixing. Complementary studies of solute association on the mesoscopic scale show a rich concentration and temperature behaviour, which reflects a complex balance of polar and non-polar interactions. Unravelling the detailed nature of this balance in simple aqueous amphiphiles may lead to a better understanding of the forces that control biomolecular structural stability and interactions.