The role of Cytochrome b6f in the control of steady-state photosynthesis: a conceptual and quantitative model

Here, we present a conceptual and quantitative model to describe the role of the Cytochrome [Formula: see text] complex in controlling steady-state electron transport in [Formula: see text] leaves. The model is based on new experimental methods to diagnose the maximum activity of Cyt [Formula: see text] in vivo, and to identify conditions under which photosynthetic control of Cyt [Formula: see text] is active or relaxed. With these approaches, we demonstrate that Cyt [Formula: see text] controls the trade-off between the speed and efficiency of electron transport under limiting light, and functions as a metabolic switch that transfers control to carbon metabolism under saturating light. We also present evidence that the onset of photosynthetic control of Cyt [Formula: see text] occurs within milliseconds of exposure to saturating light, much more quickly than the induction of non-photochemical quenching. We propose that photosynthetic control is the primary means of photoprotection and functions to manage excitation pressure, whereas non-photochemical quenching functions to manage excitation balance. We use these findings to extend the Farquhar et al. (Planta 149:78-90, 1980) model of [Formula: see text] photosynthesis to include a mechanistic description of the electron transport system. This framework relates the light captured by PS I and PS II to the energy and mass fluxes linking the photoacts with Cyt [Formula: see text], the ATP synthase, and Rubisco. It enables quantitative interpretation of pulse-amplitude modulated fluorometry and gas-exchange measurements, providing a new basis for analyzing how the electron transport system coordinates the supply of Fd, NADPH, and ATP with the dynamic demands of carbon metabolism, how efficient use of light is achieved under limiting light, and how photoprotection is achieved under saturating light. The model is designed to support forward as well as inverse applications. It can either be used in a stand-alone mode at the leaf-level or coupled to other models that resolve finer-scale or coarser-scale phenomena.

Crustal processes sustain Arctic abiotic gas hydrate and fluid flow systems

The Svyatogor Ridge and surroundings, located on the sediment-covered western flank of the Northern Knipovich Ridge, host extensive gas hydrate and related fluid flow systems. The fluid flow system here manifests in the upper sedimentary sequence as gas hydrates and free gas, indicated by bottom simulating reflections (BSRs) and amplitude anomalies. Using 2D seismic lines and bathymetric data, we map tectonic features such as faults, crustal highs, and indicators of fluid flow processes. Results indicate a strong correlation between crustal faults, crustal highs and fluid accumulations in the overlying sediments, as well as an increase in geothermal gradient over crustal faults. We conclude here that gas generated during the serpentinization of exhumed mantle rocks drive the extensive occurrence of gas hydrate and fluid flow systems in the region and transform faults act as an additional major pathway for fluid circulation.

Gas hydrate dissociation off Svalbard induced by isostatic rebound rather than global warming

Methane seepage from the upper continental slopes of Western Svalbard has previously been attributed to gas hydrate dissociation induced by anthropogenic warming of ambient bottom waters. Here we show that sediment cores drilled off Prins Karls Foreland contain freshwater from dissociating hydrates. However, our modeling indicates that the observed pore water freshening began around 8 ka BP when the rate of isostatic uplift outpaced eustatic sea-level rise. The resultant local shallowing and lowering of hydrostatic pressure forced gas hydrate dissociation and dissolved chloride depletions consistent with our geochemical analysis. Hence, we propose that hydrate dissociation was triggered by postglacial isostatic rebound rather than anthropogenic warming. Furthermore, we show that methane fluxes from dissociating hydrates were considerably smaller than present methane seepage rates implying that gas hydrates were not a major source of methane to the oceans, but rather acted as a dynamic seal, regulating methane release from deep geological reservoirs.

Methane seepage from continental slopes has been attributed to gas hydrate dissociation induced by anthropogenic bottom water warming. Here, the authors show that hydrates dissociated before the Anthropocene when the isostatic rebound induced by deglaciation of the Arctic ice sheet outpaced eustatic sea-level rise.

Performance of induction module cavity ring-down spectroscopy (IM-CRDS) for measuring δ18 O and δ2 H values of soil, stem, and leaf waters

RATIONALE

Induction module cavity ring-down spectroscopy (IM-CRDS) has been proposed as a rapid and cost-effective alternative to cryogenic vacuum distillation (CVD) and isotope ratio mass spectrometry (IRMS) for the measurement of δ¹⁸ O and δ² H values in matrix-bound waters. In the current study, we characterized the performance of IM-CRDS relative to CVD and IRMS and investigated the mechanisms responsible for differences between the methods.

METHODS

We collected a set of 75 soil, stem, and leaf water samples, and measured the δ¹⁸ O and δ² H values of each sample with four techniques: CVD and IRMS, CVD and CRDS, CVD and IM-CRDS, and IM-CRDS alone. We then calculated the isotopic errors for each of the three CRDS methods relative to CVD and IRMS, and analyzed the relationships among these errors and suites of diagnostic spectral parameters that are indicative of organic contamination.

RESULTS

The IM-CRDS technique accurately assessed the δ¹⁸ O and δ² H values of pure waters, but exhibited progressively increasing errors for soil waters, stem waters, and leaf waters. For soils, the errors were attributable to subsampling of isotopically heterogeneous source material, whereas for stems and leaves, they were attributable to spectral interference. Unexpectedly, the magnitude of spectral interference was higher for the solid samples analyzed directly via IM-CRDS than for those originally extracted via CVD and then analyzed by IM-CRDS.

CONCLUSIONS

There are many types of matrix-bound water samples for which IM-CRDS measurements include significant errors from spectral interference. As a result, spectral analysis and validation should be incorporated into IM-CRDS post-processing procedures. In the future, IM-CRDS performance could be improved through: (i) identification of the compounds that cause spectral interference, and either (ii) modification of the combustion step to completely oxidize these compounds to CO₂ , and/or (iii) incorporation of corrections for these compounds into the spectral fitting models used by the CRDS analyzers. Copyright © 2016 John Wiley & Sons, Ltd.

DIABETES AND PREDIABETES ARE SIGNIFICANTLY HIGHER IN MORBIDLY OBESE CHILDREN COMPARED WITH OBESE CHILDREN

OBJECTIVE

The objective of this study was to examine the prevalence and characteristics of comorbidities in obese and morbidly obese children with a comparison between the 2 sets of children.

METHODS

This was a retrospective electronic chart review of obese and morbidly obese children and adolescents as defined by body mass index. We evaluated medical history of comorbid conditions, medication use, and cardiovascular risk markers, including blood pressure, lipid profile, and glycosylated hemoglobin.

RESULTS

There were 1,111 subjects (African American = 635; non-Hispanic white = 364; Hispanic = 36; others = 86), of which 274 were obese and 837 were morbidly obese children with a mean age of 12.7 ± 3.37 years. Morbidly obese children had a higher prevalence of prediabetes (19.5% of obese versus 27.3% of morbidly obese; P<.0001) and type 2 diabetes (39.8% of obese versus 52.4% of morbidly obese; P<.0001). Use of medications for treatment of asthma was significantly higher in the morbidly obese group compared with the obese group (21% versus 14%; P = .01).

CONCLUSION

Morbidly obese children have a higher prevalence of diabetes, prediabetes, and use of asthma medications compared with obese children.

Diabetes Status and Race are Associated with Cardiovascular Risk Markers in Obese Adolescents

OBJECTIVE

The objective of this study was to evaluate differences in cardiovascular disease (CVD) risk markers in obese adolescents based on diabetes status and race in order to improve risk-reduction intervention strategies.

METHODS

This was a retrospective, cross-sectional study of obese adolescents, age 10 to 21 years, who were evaluated at Children's of Alabama between 2000 and 2012. Subjects were classified by glycated hemoglobin (HbA1c) as having normoglycemia, prediabetes, or type 2 diabetes mellitus (T2DM).

RESULTS

There were a total of 491 African American (AA) or Caucasian American (CA) subjects. Body mass index was not different between HbA1c and racial groups. Compared to subjects with normoglycemia or prediabetes, subjects with T2DM had higher levels of total cholesterol (TC) (178.6 ± 43.8 mg/dL vs. 161.5 ± 32.5 mg/dL vs. 162.4 ± 30.6 mg/dL; P<.0001) and low-density-lipoprotein cholesterol (107.4 ± 39.2 mg/dL vs. 97.0 ± 31.0 mg/dL vs. 97.5 ± 26.9 mg/dL; P = .0073). Compared with AA subjects, CA subjects had lower high-density-lipoprotein cholesterol (HDL-C) levels (40.4 ± 10.4 mg/dL vs. 44.3 ± 11.9 mg/dL; P = .0005) and higher non-HDL-C levels (129.6 ± 36.2 mg/dL vs. 122.5 ± 37.5 mg/dL; P = .0490). Of the characteristics studied, HbA1c had the most significant positive association with dyslipidemia and was strongly correlated with both TC (β, 4.21; P<.0001) and non-HDL-C (β, 4.3; P<.0001).

CONCLUSION

Obese adolescents with T2DM have more abnormal lipoprotein profiles than those with normoglycemia or prediabetes. Obese CA adolescents have more abnormal lipids than obese AA adolescents. HbA1c was the characteristic most highly associated with abnormal lipoprotein profiles in our subjects. Our results show that CVD risk markers in obese adolescents vary by race and HbA1c concentration.

Heralded state preparation in a superconducting qubit

We demonstrate high-fidelity, quantum nondemolition, single-shot readout of a superconducting flux qubit in which the pointer state distributions can be resolved to below one part in 1000. In the weak excitation regime, continuous measurement permits the use of heralding to ensure initialization to a fiducial state, such as the ground state. This procedure boosts readout fidelity to 93.9% by suppressing errors due to spurious thermal population. Furthermore, heralding potentially enables a simple, fast qubit reset protocol without changing the system parameters to induce Purcell relaxation.

Genomic and functional analysis of Vibrio phage SIO-2 reveals novel insights into ecology and evolution of marine siphoviruses

We report on a genomic and functional analysis of a novel marine siphovirus, the Vibrio phage SIO-2. This phage is lytic for related Vibrio species of great ecological interest including the broadly antagonistic bacterium Vibrio sp. SWAT3 as well as notable members of the Harveyi clade (V.harveyi ATTC BAA-1116 and V.campbellii ATCC 25920). Vibrio phage SIO-2 has a circularly permuted genome of 80598 bp, which displays unusual features. This genome is larger than that of most known siphoviruses and only 38 of the 116 predicted proteins had homologues in databases. Another divergence is manifest by the origin of core genes, most of which share robust similarities with unrelated viruses and bacteria spanning a wide range of phyla. These core genes are arranged in the same order as in most bacteriophages but they are unusually interspaced at two places with insertions of DNA comprising a high density of uncharacterized genes. The acquisition of these DNA inserts is associated with morphological variation of SIO-2 capsid, which assembles as a large (80 nm) shell with a novel T=12 symmetry. These atypical structural features confer on SIO-2 a remarkable stability to a variety of physical, chemical and environmental factors. Given this high level of functional and genomic novelty, SIO-2 emerges as a model of considerable interest in ecological and evolutionary studies.

Quantitative methods for analysing cumulative effects on fish migration success: a review

It is often recognized, but seldom addressed, that a quantitative assessment of the cumulative effects, both additive and non-additive, of multiple stressors on fish survival would provide a more realistic representation of the factors that influence fish migration. This review presents a compilation of analytical methods applied to a well-studied fish migration, a more general review of quantitative multivariable methods, and a synthesis on how to apply new analytical techniques in fish migration studies. A compilation of adult migration papers from Fraser River sockeye salmon Oncorhynchus nerka revealed a limited number of multivariable methods being applied and the sub-optimal reliance on univariable methods for multivariable problems. The literature review of fisheries science, general biology and medicine identified a large number of alternative methods for dealing with cumulative effects, with a limited number of techniques being used in fish migration studies. An evaluation of the different methods revealed that certain classes of multivariable analyses will probably prove useful in future assessments of cumulative effects on fish migration. This overview and evaluation of quantitative methods gathered from the disparate fields should serve as a primer for anyone seeking to quantify cumulative effects on fish migration survival.

Motoneuron programmed cell death in response to proBDNF

Motoneurons (MN) as well as most neuronal populations undergo a temporally and spatially specific period of programmed cell death (PCD). Several factors have been considered to regulate the survival of MNs during this period, including availability of muscle-derived trophic support and activity. The possibility that target-derived factors may also negatively regulate MN survival has been considered, but not pursued. Neurotrophin precursors, through their interaction with p75(NTR) and sortilin receptors have been shown to induce cell death during development and following injury in the CNS. In this study, we find that muscle cells produce and secrete proBDNF. ProBDNF through its interaction with p75(NTR) and sortilin, promotes a caspase-dependent death of MNs in culture. We also provide data to suggest that proBDNF regulates MN PCD during development in vivo.

Soil warming alters nitrogen cycling in a New England forest: implications for ecosystem function and structure

Global climate change is expected to affect terrestrial ecosystems in a variety of ways. Some of the more well-studied effects include the biogeochemical feedbacks to the climate system that can either increase or decrease the atmospheric load of greenhouse gases such as carbon dioxide and nitrous oxide. Less well-studied are the effects of climate change on the linkages between soil and plant processes. Here, we report the effects of soil warming on these linkages observed in a large field manipulation of a deciduous forest in southern New England, USA, where soil was continuously warmed 5°C above ambient for 7 years. Over this period, we have observed significant changes to the nitrogen cycle that have the potential to affect tree species composition in the long term. Since the start of the experiment, we have documented a 45% average annual increase in net nitrogen mineralization and a three-fold increase in nitrification such that in years 5 through 7, 25% of the nitrogen mineralized is then nitrified. The warming-induced increase of available nitrogen resulted in increases in the foliar nitrogen content and the relative growth rate of trees in the warmed area. Acer rubrum (red maple) trees have responded the most after 7 years of warming, with the greatest increases in both foliar nitrogen content and relative growth rates. Our study suggests that considering species-specific responses to increases in nitrogen availability and changes in nitrogen form is important in predicting future forest composition and feedbacks to the climate system.

STUDIES ON THE PATHOGENESIS OF STAPHYLOCOCCAL INFECTION : I. THE EFFECT OF REPEATED SKIN INFECTIONS

The influence of repeated staphylococcal infection of rabbit skin upon the characteristics of the experimentally induced lesion was studied. It was found that the repeated infection was associated with the development of delayed hypersensitivity unaccompanied by the appearance of demonstrable serum antibody. The delayed hypersensitivity to the staphylococcus resulted in an increased infectivity of the organism in skin of the sensitized animal, characterized by intensification of the lesions seen with large bacterial inocula and the induction of abscesses with inocula incapable of producing any lesion in normal rabbit skin. Similarly, the severity of experimentally induced pyoarthrosis was greater in sensitized than in normal rabbits. Induction of delayed hypersensitivity by vaccination of rabbits with washed heat-killed staphylococci resulted in the same increased severity of the infection and an increase in infectivity of the microorganism. In contrast to the observations of cutaneous and joint infection, the sensitized animals appeared to be less susceptible to severe infection of the anterior chamber of the eye. The role of immunity and hypersensitivity in staphylococcal infection is discussed and the possibility that non-specific inflammation may influence staphylococcal infection in the same way as specific hypersensitivity is indicated. Studies to further elucidate this are presented in the following pages.

STUDIES ON THE PATHOGENESIS OF STAPHYLOCOCCAL INFECTION : III. THE EFFECT OF TISSUE NECROSIS AND ANTITOXIC IMMUNITY

Necrosis of rabbit skin produced by thermal injury was found to result in a striking increase in local infectivity of staphylococci that were coagulase-positive and hemolytic, but no local increase in the infectivity of non-pathogenic staphylococci. Infection produced in necrotic burns extended beyond the area of burn and was characterized by hemorrhage, edema, and necrosis of contiguous normal skin. Such infections, however, never resulted in bacteriemia or metastatic abscesses, and there was no effect of the necrotic burn upon the infectivity of staphylococci injected into normal skin of the burned animal. Recovery of rabbits from severe burn infections was associated with the development of high titers of serum antibody to the alpha hemolysin or dermonecrotoxin of the staphylococcus. Thirty to 100 days after the initial burn infection, it was found that rabbits could no longer be infected in a necrotic burn, although infection induced in normal skin of these resistant animals was no different from that in normal rabbits. Immunity to infection by pathogenic staphylococci in necrotic burns could be induced by vaccination with potent alpha hemolysin toxoid, and this immunity was passively transferable with rabbit antiserum. No strain specificity was detected for this immunity in that immunization with toxoid prepared from bacteriophage type 52/42B/80/81 staphylococci protected animals against infection in a necrotic burn by other typable and non-typable staphylococci. Histopathological study of infected necrotic burns in normal rabbits showed extensive necrosis, hemorrhage, edema, and many masses of bacteria but leucocytic infiltration was observed only at the margin of the infection. In contrast, the infected necrotic burns in animals immunized with alpha hemolysin toxoid showed few bacteria and marked leucocytic infiltration throughout the burn. These experiments have, therefore, demonstrated a significant immunity to infection by pathogenic staphylococci in necrotic tissue but not in normal skin, associated with serum antibody to the alpha hemolysin or dermonecrotoxin of the bacteria. The implications of these findings are discussed.

Muscle imbalance and reduced ankle joint motion in people with hammer toe deformity

BACKGROUND

Multiple factors may contribute to hammer toe deformity at the metatarsophalangeal joint. The purposes of this study were to (1) compare the ratio of toe extensor/flexor muscle strength in toes 2-4 among groups with and without hammer toe deformity, (2) to determine correlations between the ratio of toe extensor/flexor muscle strength in toes 2-4, and metatarsophalangeal joint deformity (3) to determine if other clinical measures differ between groups and if these measures are correlated with metatarsophalangeal joint angle.

METHODS

Twenty-seven feet with visible hammer toe deformity and 31 age matched feet without hammer toe deformity were tested. Toe muscle strength was measured using a dynamometer and the ratio of toe extensor muscle strength to flexor muscle strength was calculated. Metatarsophalangeal joint angle was measured from a computerized tomography image. Ankle and subtalar joint range of motion, and tibial torsion were measured using goniometry.

FINDINGS

Extensor/flexor toe muscle strength ratio was 2.3-3.0 times higher in the hammer toe group compared to the non-hammer toe group, in toes 2-4. The ratios of extensor/flexor toe muscle strength for toes 2-4 and metatarsophalangeal joint angle were highly correlated (r=0.69-0.80). Ankle dorsiflexion and metatarsophalangeal joint angle were negatively correlated for toes 2-4 (r=-0.38 to -0.56) as were eversion and metatarsophalangeal joint angle.

INTERPRETATION

These results provide insight into potential risk factors for the development of hammer toe deformity. Additional research is needed to determine the causal relationship between hammer toe deformity and the ratio of toe extensor/flexor muscle strength in toes 2-4.

A strategic framework for responding to coral bleaching events in a changing climate

The frequency and severity of mass coral bleaching events are predicted to increase as sea temperatures continue to warm under a global regime of rising ocean temperatures. Bleaching events can be disastrous for coral reef ecosystems and, given the number of other stressors to reefs that result from human activities, there is widespread concern about their future. This article provides a strategic framework from the Great Barrier Reef to prepare for and respond to mass bleaching events. The framework presented has two main inter-related components: an early warning system and assessment and monitoring. Both include the need to proactively and consistently communicate information on environmental conditions and the level of bleaching severity to senior decision-makers, stakeholders, and the public. Managers, being the most timely and credible source of information on bleaching events, can facilitate the implementation of strategies that can give reefs the best chance to recover from bleaching and to withstand future disturbances. The proposed framework is readily transferable to other coral reef regions, and can easily be adapted by managers to local financial, technical, and human resources.

Neurotrophic factors and neuronal death

The well-documented physiological role of nerve growth factor (NGF) in peripheral sympathetic and neural-crest-derived sensory neurons in vivo has its exact counterpart in vitro. This provided the conceptual basis for developing in vitro analytical procedures for the purification of new neurotrophic molecules. The experimental approaches used are discussed in the context of the purification of new neurotrophic factors, brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF). The importance of the modulatory role played by extracellular matrix molecules, in particular laminin, on both NGF-mediated and BDNF-mediated survival effects is also delineated. BDNF is a very basic (pI approximately 10) molecule of about 12 kDa, having physico-chemical characteristics close to those of the monomer of NGF. However, the spectrum of its biological actions is distinctly different from that of NGF. In particular, BDNF supports the survival of retinal ganglion cells and placode-derived peripheral sensory neurons which are not supported by NGF. The trophic supply of primary sensory neurons projecting to both the central nervous system and the periphery is discussed. It is hypothesized that sensory neurons receive limited quantities of neurotrophic molecules from both peripheral and central axons, a mechanism ensuring the survival of neurons adequately connected with both peripheral and central targets.

Lisfranc injury in a national hockey league player: a case report

Tarsometatarsal joint dislocations and fracture-dislocations are uncommon injuries most frequently resulting from high-energy trauma as encountered in crush injuries, falls, and motor vehicle accidents. Although less common in athletes, this injury is being recognized with greater frequency and may carry a poor prognosis for return to high levels of competition. These injuries present a considerable challenge to orthopedic surgeons caring for athletes because of the prolonged period of recovery often required [ 1,2,5,6,12]. The literature contains descriptions of this injury in football players, gymnasts, tennis players, and track and field athletes [2,5,9]. To our knowledge, no report of such a Lisfranc injury to a hockey player has been described. This is a case report of a National Hockey League player that sustained a Lisfranc injury requiring surgical stabilization, but was able to return to elite hockey play.

Evaluation of a dual-arm Archimedean spiral array for microwave hyperthermia

PURPOSE

This effort describes a third-party performance evaluation of a novel, commercial, dual-armed Archimedean spiral array hyperthermia applicator. The applicator is analysed for its ability to couple efficiently into muscle equivalent phantom loads, operate over a broad bandwidth to help accommodate variable tissue properties and generate predictable and repeatable SAR contours that are adaptable to clinically probable disease shapes.

MATERIALS AND METHODS

Characterization of the applicator includes E-field and return-loss measurements in liquid muscle tissue-equivalent phantom, as well as comparison of 'treatment-planning' simulations of several possible array SAR patterns with measured SAR from non-coherently driven spiral array antennae.

RESULTS

The applicator demonstrates a reasonably low return loss over a large bandwidth and the ability to generate a very uniform heating pattern. Ability to adjust SAR contours spatially to fit specific shapes is also demonstrated.

CONCLUSIONS

This device should prove a welcome addition to a currently limited set of superficial heating applicators to provide controllable heating of superficial tissue disease.

Preliminary x-ray characterization of authentic providence virus and attempts to express its coat protein gene in recombinant baculovirus

Providence Virus (PrV) is a non-envoloped, T = 4 icosahedral beta-tetravirus that undergoes autocatalytic cleavage of its coat protein precursor after capsid assembly. This is also a well characterized function of Nudaurelia capensis omega virus (NomegaV), a member of the related omegatetraviruses, whose x-ray structure has been determined. Virus-like particle (VLP) production of PrV in a recombinant baculovirus expression system was attempted to obtain high VLP yields for comparison of structural and autocatalytic active site properties between these virus groups. This resulted in insoluble aggregates of PrV coat protein even though NomegaV VLPs have been successfully produced in the same system. Betatetraviruses may be more dependent on compartmentalization and availability of their full-length genome for proper folding and assembly. However, crystals were grown of limited quantities of authentic PrV produced in cell culture and a partial X-ray data set collected to 3.8 A resolution. The virus particle position and orientation in the unit cell was determined by space group consideration and rotation function analysis. A phasing model, based on NomegaV, was developed to initiate the structure solution of PrV.

Preoperative evaluation of live renal donors using multislice CT angiography

AIM

To determine the accuracy of multidetector row CT renal angiography in the preoperative evaluation of live kidney donors, and to identify potential pitfalls when reporting.

METHODS

Between July 1998 and June 2003, 74 consecutive live renal donors underwent contrast-enhanced multidetector row CT renal angiography before donor nephrectomy. The operative notes and radiological reports of all cases were reviewed retrospectively. Where a significant discrepancy was identified, the archived images were reviewed by two radiologists in the light of the intraoperative findings.

RESULTS

A total of 12 discrepancies were identified in 11 of the 74 cases (15%). In the preoperative CT angiography reports, 4 accessory arteries, 6 early-branching renal arteries, 1 duplicated renal vein and 1 accessory ureter were not identified; 9 of these were evident on review, but were not detected at the time of reporting. In 3 cases (1 accessory artery, the duplicated renal vein and the accessory ureter), the anomaly was not visible on review of the CT angiographic data, even with the benefit of hindsight. Surgical feedback during the study period resulted in modifications to CT technique and improved performance.

CONCLUSION

In the majority of cases, there was good correlation between preoperative CT renal angiography and operative findings. Most discrepancies were due either to an oversight by the reporting radiologist, or failure to fully appreciate the potential surgical significance of certain findings. Regular surgical feedback plays a valuable role in improving reporting accuracy and maintaining imaging standards.

BK and JC polyomaviruses are not associated with idiopathic pulmonary fibrosis

We sought to determine if the BK and JC polyomaviruses were associated with idiopathic pulmonary fibrosis (IPF). We did not detect the BK or JC polyomaviruses in lung tissue extracts from 33 patients with IPF by using real-time PCR, which suggests that an etiologic association is unlikely.

Tendon Achilles lengthening for the treatment of neuropathic ulcers causes a temporary reduction in forefoot pressure associated with changes in plantar flexor power rather than ankle motion during gait

The purposes of this study were to determine the effects of tendon Achilles lengthening (TAL) on ambulatory plantar pressures and ankle range of motion, moment, and power, and to determine whether changes in forefoot pressure after treatment of a neuropathic ulcer are related to changes in ankle dorsiflexion range of motion (DFROM) or plantar flexor (PF) power during gait. Pressure and gait tests were performed before treatment, and at 3 weeks and 8 months after treatment in two randomly assigned groups of subjects with diabetes, equinus deformity, and a neuropathic forefoot ulcer treated with TAL and total contact casting (TAL group, n=14), or total contact casting alone (TCC group, n=14). The TAL group had an initial decrease in forefoot peak pressure (PP) (27%), forefoot pressure-time integral (PTI) (42%), PF moment (53%), and PF power (65%), along with an initial increase in rear foot PP (34%), rear foot PTI (48%), and DFROM (74%). Post-surgical changes in rear foot pressure and DFROM were maintained up to 8 months after treatment with TAL, whereas forefoot pressure and PF moment and power increased significantly. Changes in forefoot pressure after treatment in either group were correlated with changes in PF power (r=0.45-0.60), but not with changes in DFROM during gait (r=-0.02-0.08). Results suggest TAL causes a temporary reduction in forefoot pressure primarily by reducing PF power during gait. The initial decrease in forefoot pressure, followed by progressive reloading of forefoot tissues as PF muscles regain strength after TAL, may help reduce the risk of ulcer recurrence in patients with diabetes.

Virus stability and protein-nucleic acid interaction as studied by high-pressure effects on nodaviruses

In this work, we evaluate the stability, dynamics and protein-nucleic acid interaction in Flock House virus (FHV). FHV is an RNA insect virus, non-enveloped, member of the family Nodaviridae. It is composed of a bipartite single-stranded RNA genome packaged in an icosahedral capsid of 180 copies of an identical protein (alpha protein). A fundamental property of many animal viruses is the post-assembly maturation required for infectivity. FHV is constructed as a provirion, which matures to an infectious virion by cleavage of alpha protein into beta and gamma subunits. We used high pressure, temperature and chemical denaturing agents to promote perturbation of the viral capsid. These effects were monitored by spectroscopy measurements (fluorescence, light scattering and CD) and size-exclusion chromatography. The data showed that FHV was stable to pressures up to 310 MPa at room temperature. The fluorescence emission and light scattering values showed small changes that were reversible after decompression. When we combined pressure and sub-denaturing urea concentrations (1 M), the changes were more drastic, suggesting dissociation of the capsid. However, these changes were reversible after pressure release. The complete dissociation of FHV could be observed only under high urea concentrations (10 M). There were no significant changes in emission spectra up to 5 M urea. FHV also was stable when we used temperature treatments (high and low). We also compared the effects of urea and pressure on FHV wild type and cleavage-defective mutant VLPs (virus-like particles). The VLPs and authentic particles are distinguishable by protein-RNA interactions, since VLPs pack cellular RNA and native particles contain viral RNA. Our results demonstrated that native particles are more stable than VLPs to physical and chemical treatments. Our data point to the specificity of the interaction between the capsid protein and the viral RNA. This specificity is crucial to the stability of the particle, which makes this interaction an excellent target for drug development.

An empirical study of the impact of complexity on participation in horserace betting

The aim of the research reported in this paper was to explore empirically whether levels of participation in horserace betting are affected by the complexity of the betting task. The study employed a systematic random sample of 1161 betting decisions made in UK offcourse betting offices during 1987. The research was conducted in a naturalistic setting where it was possible to grade complexity and to measure levels of participation. Complexity was defined in terms of both the number of alternatives in the decision-maker's choice set (number of horses in a race) and the complexity of the attributes set for each horserace (handicap vs. non-handicap races). Results indicated that bettors are not inhibited by alternative-based complexity, but may be inhibited to some extent by attribute-defined complexity.

Sediment microbes of deep-sea bioherms on the northwest shelf of Australia

The northwest shelf of Australia is a region with known petroleum reserves. Recent geological investigations have revealed carbonate knolls postulated to be of biological origin. Sediment microbial populations at three sites on the northwest shelf, Pee Shoal, Mermaid Reef, and Scott Reef, were investigated for the presence of hydrocarbon-degrading bacteria. From two sampling trips, 246 bacterial strains were purified, and 182 of these strains displayed preferential growth on hydrocarbon-selective media. Strains were tested for nutrient specificity using single hydrocarbon fermentations. Metabolic profiles were constructed using biochemical testing, fatty acid analysis, and metabolic rate experiments. 16S rRNA gene sequence analysis of four strains identified these strains as members of the genera Sphingomonas, Bacillus, and Microbacterium, and one strain as a member of the alpha-Proteobacteria. The potential of these strains as bioindicators of hydrocarbon pollutants or for bioremediation in marine environments is discussed.

Cowpea mosaic virus: from the presentation of antigenic peptides to the display of active biomaterials

The potential of cowpea mosaic virus (CPMV), a plant icosahedral virus, for the presentation of foreign peptides and proteins is reported. The most prominent feature at the virus surface is a region of the smaller of the two coat proteins (S) which has been extensively used for the insertion of foreign peptides. Given the availability of the three-dimensional structure of the native virus and the amenability of foreign peptide-expressing CPMV chimeras to crystallisation, immunological data can be correlated with the conformational state of the foreign insert. The latter is influenced by proteolysis which occurs within the foreign inserts. In an effort to offer an alternative context for peptide expression, extensive exploration of a second region of the S protein is reported with respect to tolerance to small insertions. Moreover, to make CPMV suitable for a wider spectrum of presentation, a technique was developed to allow surface coupling of a peptide which can serve as the anchoring point for a range of proteins. This new approach is also widely applicable for the direct chemical cross-linking of peptides and full-length protein domains to the viral capsid.

Bilevel multidisciplinary discharge planning and length of stay

As health care funding gets more and more tenuous, leaders in all institutions are called upon to find innovative ways to reduce costs while maintaining quality. It is possible to realize undreamed-of savings by reengineering certain processes, but such an undertaking demands that wholesale changes in the corporate culture and substantial effort at all levels. This paper reports a long-term project at a large, urban, tertiary care institution, the redesign of discharge planning to improve patient care and reduce lengths of stay and related expenses.

Evolutionary and taxonomic implications of conserved structural motifs between picornaviruses and insect picorna-like viruses

A comparison of the recently determined structure of an insect picorna-like virus, Cricket paralysis virus (CrPV), with that of the mammalian picornaviruses shows that several structural features are highly conserved between these viruses. These conserved features include the topology of the coat proteins, the conformation of most loops, and the general arrangement of the internally located N-terminal arms of the coat proteins. The conformational conservation of the N-termini of the three major coat proteins between CrPV and the picornaviruses suggests a putative ancestral T = 3 virus. Comparisons of the genome structure and amino-acid sequence of the coat proteins of CrPV with a number of other insect picorna-like viruses show that most of them belong to a novel group, recently given the interim name Cricket paralysis-like viruses. Two other insect picorna-like viruses, Infectious flacherie virus (IFV) and Sacbrood virus (SBV), for which the genome sequences have recently been determined, have very different coat protein sequences and a genome organization more like the picornaviruses. However, the position of the small VP4 protein in the structural protein polyprotein as well as the mechanism for its cleavage from VP3 upon assembly strongly suggests an evolutionary link to the "Cricket paralysis-like viruses". We propose that the picornaviruses, Cricket paralysis-like viruses and IFV/SBV group are a natural assemblage. The ancestor for this assemblage had a structure based upon the CrPV/picornavirus paradigm and a genome encoding a single major coat protein; gene duplication and rearrangements have subsequently produced the viruses that we observe today. We also discuss the possible relatives of the proposed assemblage and the likely implications of future structural studies that may be carried out on the putative relatives.

Obstructive jaundice secondary to lymphoma in childhood

In children, biliary obstruction secondary to lymphoma is rare. Previous reports in adults and children suggest that these lymphomas are associated with a poor prognosis. The authors reviewed the medical records and imaging studies of 4 children treated for pancreaticobiliary lymphoma at our children's hospital over the past 10 years. All 4 presented with jaundice. Abdominal ultrasound scan and computed tomography (CT) scans were helpful in defining the anatomy of the obstruction. In the cases of involvement of the porta hepatis, the diagnosis was made by biopsy. In one child a mass was in the head of the pancreas, and evaluation of frozen section biopsy results were not diagnostic for lymphoma, and a major resection was performed. All the lymphomas were of nonHodgkin's B-cell type and one was a Burkitt's lymphoma. All responded promptly to chemotherapy. One child had a testicular relapse and currently is receiving additional therapy. Pancreaticobiliary lymphomas are an unusual cause of obstructive jaundice in children. Biopsy alone without resection or biliary drainage is recommended surgical therapy. Long-term survival rate in children with this disorder appears to be more promising than previously reported. J Pediatr Surg 36:1792-1795.

Comparing transforming growth factor beta-2 and fibronectin as pleurodesing agents

BACKGROUND

We have recently demonstrated that transforming growth factor beta-2 (TGF-beta2) can produce effective pleurodesis. Whether this effect can be reproduced by the use of its downstream proteins is not known. This study compared the effectiveness of TGF-beta2 and fibronectin in inducing pleurodesis in rabbits.

METHODOLOGY

New Zealand white rabbits (1.5-2.0 kg) were given 1.7 microg of TGF-beta2 (n=5) or 2.0 mg of cellular fibronectin (n=4) intrapleurally via a chest tube. The induced pleural fluid was collected and analyzed. The rabbits were sacrificed after 14 days. The pleurodesis was graded macroscopically from 1 (none) to 8 (symphysis > 50%).

RESULTS

All rabbits in the TGF-beta2 group developed effective pleurodesis while none in the fibronectin group had scores > 2 (pleurodesis scores 7.0 +/- 0.6 vs 1.3 +/- 0.3, P < 0.001). Rabbits that received TGF-beta2 produced large amounts of pleural fluid initially (< 4 days). Microscopically, the pleura of rabbits in the TGF-beta2 group showed prominent spindle cell proliferation and collagen deposition, but no significant inflammation or mesothelial proliferation. Pleural tissues of rabbits in the fibronectin group had occasional thin collagen deposits only. The intrapleural administration of 2.0 mg of fibronectin, a downstream product of TGF-beta, did not induce effective pleurodesis, as did the intrapleural administration of TGF-beta2.

CONCLUSIONS

The present study suggests that the mechanism by which TGF-beta2 induces pleurodesis is not predominantly dependent on the production of fibronectin.

Effects of paramyxoviral infection on airway epithelial cell Foxj1 expression, ciliogenesis, and mucociliary function

To elucidate molecular mechanisms underlying the association between respiratory viral infection and predisposition to subsequent bacterial infection, we used in vivo and in vitro models and human samples to characterize respiratory virus-induced changes in airway epithelial cell morphology, gene expression, and mucociliary function. Mouse paramyxoviral bronchitis resulted in airway epithelial cell infection and a distinct pattern of epithelial cell morphology changes and altered expression of the differentiation markers beta-tubulin-IV, Clara cell secretory protein, and Foxj1. Furthermore, changes in gene expression were recapitulated using an in vitro epithelial cell culture system and progressed independent of the host inflammatory response. Restoration of mature airway epithelium occurred in a pattern similar to epithelial cell differentiation and ciliogenesis in embryonic lung development characterized by sequential proliferation of undifferentiated cells, basal body production, Foxj1 expression, and beta-tubulin-IV expression. The effects of virus-induced alterations in morphology and gene expression on epithelial cell function were illustrated by decreased airway mucociliary velocity and impaired bacterial clearance. Similar changes in epithelial cell Foxj1 expression were also observed in human paramyxoviral respiratory infection. Taken together, these model systems of paramyxoviral respiratory infection mimic human pathology and identify epithelial cell Foxj1 expression as an early marker of epithelial cell differentiation, recovery, and function.

Mechanisms of acid-catalyzed Z/E isomerization of imines

The kinetics and mechanism of acid-catalyzed Z/E isomerization of O-methylbenzohydroximoyl chloride (1Za and 1Ea), methyl O-methylbenzohydroximate (1Zb and 1Eb), ethyl O-methylbenzohydroximate (1Zc and 1Ec and five para and meta substituted derivatives), O-methylcinnamohydroximoyl chloride (2Za and 2Ea), and methyl O-methylcinnamohydroximate (2Zb and 2Zb) have been investigated. The kinetics of Z/E isomerization of these imines have been studied in glacial acetic acid (1Ea and 1Zc) and in dioxane solutions containing HCl, trifluoromethanesulfonic acid, or tetrafluoroboric acid (1Ea, 1Zb, 2Ea, and 2Zb). The isomerization takes place by either (a) rotation about the carbon-nitrogen double bond of the protonated imine (iminium ion rotation) or (b) nucleophilic attack on the protonated imine to form a tetrahedral intermediate that undergoes stereomutation and loss of the nucleophile (nucleophilic catalysis). The hydroximoyl chlorides 1Eaand 2Ea only isomerize by the nucleophilic catalysis mechanism. The hydroximate 1Zb appears to be capable of isomerizing by either mechanism. The hydroximate 2Zb may be isomerizing only by iminium ion rotation. Theoretical calculations support the notion that increased conjugation in the protonated imine increases the rate of iminium ion rotation.

Developmental changes in BDNF protein levels in the hamster retina and superior colliculus

Quantitative studies of ontogenetic changes in the levels of brain-derived neurotrophic factor (BDNF) mRNA and its effector, BDNF protein, are not available for the retinal projection system. We used an electrochemiluminescence immunoassay to measure developmental changes in the tissue concentration of BDNF within the hamster retina and superior colliculus (SC). In the SC, we first detected BDNF (about 9 pg/mg tissue) on embryonic day 14 (E14). BDNF protein concentration in the SC rises about fourfold between (E14) and postnatal day 4 (P4), remains at a plateau through P15, then declines by about one-third to attain its adult level by P18. By contrast, BDNF protein concentration in the retina remains low (about 1 pg/mg tissue) through P12, then increases 4.5-fold to attain its adult level on P18. The developmental changes in retinal and collicular BDNF protein concentrations are temporally correlated with multiple events in the structural and functional maturation of the hamster retinal projection system. Our data suggest roles for BDNF in the cellular mechanisms underlying some of these events and are crucial to the design of experiments to examine those roles.

Characterization of virus-like particles assembled in a recombinant baculovirus system expressing the capsid protein of a fish nodavirus

Betanodaviruses are causative agents of neurological disorders in several species of fish. We cloned and sequenced the RNA2 segment of two grouper viruses isolated from Epinephelus malabaricus (malabaricus grouper nervous necrosis virus, MGNNV) and Epinephelus lanceolatus (dragon grouper nervous necrosis virus, DGNNV). The sequences of the two RNAs were 99% identical and comparison with previously sequenced RNA2 segments of fish nodaviruses striped jack nervous necrosis virus, Atlantic halibut virus, sea bass encephalitis virus, and greasy grouper nervous necrosis virus (GGNNV) revealed that MGNNV and DGNNV were most closely related to GGNNV. No correlation of sequence with geographical habitat was detected. The MGNNV coat protein, the gene product of RNA2, was expressed in Sf21 cells with a recombinant baculovirus system and virus-like particles (VLPs) spontaneously formed. Two types of VLPs were observed: a slower sedimenting particle was RNase-sensitive and stain-permeable, while the faster sedimenting particle survived RNase treatment and was not stain-permeable. An image reconstruction of the latter, obtained with electron cryomicroscopy data, revealed a morphology consistent with T = 3 quasi-symmetry but with features significantly different from insect nodavirus structures at the same resolution. This assembly system allows the first biophysical comparisons of fish and insect nodavirus structure, assembly, and stability.

Sentinel lymph node detection and microstaging in vulvar carcinoma

OBJECTIVE

To determine the efficacy of using complementary techniques for detecting sentinel lymph nodes (SLNs) in vulvar carcinoma and to evaluate the utility of microstaging techniques.

STUDY DESIGN

Patients with invasive vulvar carcinoma underwent sentinel lymph node detection (SLND) using preoperative lymphoscintigraphy, intraoperative isosulfan blue dye injection and an intraoperative hand-held gamma-detecting probe. Eleven patients were included and a total of 16 groins evaluated. Sentinel nodes identified were excised, bisected and examined in surgical pathology using hematoxylin and eosin (H&E) staining. Pathologically negative SLNs were subjected to additional microstaging via serial sectioning and immunohistochemical staining for cytokeratin. Surgical management of the vulvar cancer and extent of inguinal-femoral lymphadenectomy were individualized based on clinicopathologic parameters, including depth of invasion, location of the tumor and patient performance status.

RESULTS

Lymphoscintigraphy, dye and gamma-detector methods led to the total detection of 16, 19 and 17 SLNs, respectively. In two cases the isosulfan blue dye assisted in the isolation of an additional sentinel node over that of the gamma probe. Each method individually identified SLNs in 10/11 patients (91%). A total of 19 sentinel nodes were isolated. One SLN (5%) was positive for metastatic disease using H&E staining. Of the 18 negative SLNs, 2 (11%) had micrometastases (< 0.2 mm) upon serial sectioning and immunohistochemical staining.

CONCLUSION

Combined-modality mapping enhances detection of SLNs in vulvar carcinoma. Histologic microstaging improves the detection of micrometastases within SLNs.

Immunohistochemical analysis of nuclear versus cytoplasmic staining of WT1 in malignant mesotheliomas and primary pulmonary adenocarcinomas

CONTEXT

Previous studies have indicated certain immunohistochemical markers, including WT1, may be helpful in distinguishing adenocarcinomas from mesotheliomas, but to date there are no reliable, widely accepted, commercially available antibodies positive in mesotheliomas and negative in adenocarcinomas. We compared the nuclear and cytoplasmic staining patterns of WT1 in these 2 malignancies using a commercially available antibody and examined the expression of 2 other previously reported positive markers, calretinin and thrombomodulin.

METHODS

Sixty-seven mesotheliomas and 51 adenocarcinomas, all paraffin embedded, were retrieved from recent case files. The diagnosis of mesothelioma was based on typical clinical and morphologic features, as well as immunohistochemistry; electron microscopy had been performed on 16 cases. The diagnosis of adenocarcinoma was based on typical light microscopic findings and a positive stain for mucin. Commercially available antibodies to WT1, thrombomodulin, and calretinin were applied. Because of the conflict surrounding calretinin, 2 anticalretinin antibodies (from Chemicon Inc and Zymed Laboratories) were utilized.

RESULTS

Fifty of 67 mesotheliomas showed strong nuclear staining with WT1. No adenocarcinomas (0/51) showed nuclear staining. Twenty-three of 67 mesotheliomas were positive for thrombomodulin, and 35 of 67 mesotheliomas were positive for calretinin with the Chemicon antibody. Nine of 15 mesotheliomas were positive for calretinin with the Zymed antibody.

CONCLUSIONS

Thrombomodulin and calretinin did not prove useful in discriminating between mesotheliomas and adenocarcinomas. The degree of positivity with calretinin may be dependent on the specific antibody utilized. Nuclear staining for WT1 is highly specific for mesothelioma and, in the appropriate clinical setting, can be a helpful adjunct in the distinction between adenocarcinomas and mesotheliomas.

Swelling at the angle of the mandible: imaging of the pediatric parotid gland and periparotid region

The pediatric parotid gland and periparotid region are subject to a variety of lesions and are most often evaluated with ultrasonography (US), contrast material-enhanced computed tomography (CT), and magnetic resonance (MR) imaging. US may be used to assess the size of the parotid gland, distinguish diffuse from focal disease, assess vascularity and adjacent vascular structures, distinguish cystic from solid lesions, and guide fine-needle aspiration. However, further evaluation with CT or MR imaging may be needed to better define the nature and extent of disease. CT is the imaging modality of choice for most pediatric parotid disease (including acute inflammation, abscess, calculi, and major salivary duct obstruction) and most solid masses and may obviate sedation. However, a mass associated with facial nerve symptoms should be evaluated with MR imaging because it is the only modality that can consistently demonstrate the facial nerve. Findings at US, CT, and MR imaging allow localization of parotid lesions and may suggest a specific cause. Clinical information, familiarity with normal parotid anatomy at various stages of its development, and knowledge of the imaging characteristics of parotid and periparotid lesions are essential for appropriate radiologic evaluation. This information can be used to guide therapy and plan a surgical approach.

Characterization of an unknown component in Noscapine using liquid chromatography-mass spectrometry and proton nuclear magnetic resonance spectroscopy

Analytical and semipreparative LC methods were used to quantitate and isolate an unknown component (Impurity A) found in samples of bulk Noscapine. This component was also examined by LC-ESI-MS and 1H-NMR. It was concluded that the structure of Impurity A only differed from Noscapine in that it possessed a hydroxyl group at position 21 of the isobenzofuranone moiety.