The thymus: what's normal and what's not? Problem-solving with MRI

Anterior mediastinal masses can be difficult to characterise on computed tomography (CT) due to the wide spectrum of normal appearances of thymic tissue as well as the challenge of differentiating between benign and malignant pathologies. Additionally, attenuation of cystic mediastinal lesions can be misinterpreted on CT due to varying attenuation values. Anecdotally, non-vascular magnetic resonance imaging (MRI) of the thorax is underutilised across radiology departments in the UK, but has been shown to improve diagnostic certainty and reduce unnecessary surgical intervention. T2-weighted MRI is useful in confirming the cystic nature of lesions, whereas chemical shift techniques can be utilised to document the presence of macroscopic and intra-cellular fat and thus help distinguish between benign and malignant pathologies. In this review article, we present a practical approach to using MRI for the characterisation of anterior mediastinal lesions based on our clinical experience in a UK district general hospital.

Processes of consent in research for adults with impaired mental capacity nearing the end of life: systematic review and transparent expert consultation (MORECare_Capacity statement)

BACKGROUND

Involving adults lacking capacity (ALC) in research on end of life care (EoLC) or serious illness is important, but often omitted. We aimed to develop evidence-based guidance on how best to include individuals with impaired capacity nearing the end of life in research, by identifying the challenges and solutions for processes of consent across the capacity spectrum.

METHODS

Methods Of Researching End of Life Care_Capacity (MORECare_C) furthers the MORECare statement on research evaluating EoLC. We used simultaneous methods of systematic review and transparent expert consultation (TEC). The systematic review involved four electronic databases searches. The eligibility criteria identified studies involving adults with serious illness and impaired capacity, and methods for recruitment in research, implementing the research methods, and exploring public attitudes. The TEC involved stakeholder consultation to discuss and generate recommendations, and a Delphi survey and an expert 'think-tank' to explore consensus. We narratively synthesised the literature mapping processes of consent with recruitment outcomes, solutions, and challenges. We explored recommendation consensus using descriptive statistics. Synthesis of all the findings informed the guidance statement.

RESULTS

Of the 5539 articles identified, 91 met eligibility. The studies encompassed people with dementia (27%) and in palliative care (18%). Seventy-five percent used observational designs. Studies on research methods (37 studies) focused on processes of proxy decision-making, advance consent, and deferred consent. Studies implementing research methods (30 studies) demonstrated the role of family members as both proxy decision-makers and supporting decision-making for the person with impaired capacity. The TEC involved 43 participants who generated 29 recommendations, with consensus that indicated. Key areas were the timeliness of the consent process and maximising an individual's decisional capacity. The think-tank (n = 19) refined equivocal recommendations including supporting proxy decision-makers, training practitioners, and incorporating legislative frameworks.

CONCLUSIONS

The MORECare_C statement details 20 solutions to recruit ALC nearing the EoL in research. The statement provides much needed guidance to enrol individuals with serious illness in research. Key is involving family members early and designing study procedures to accommodate variable and changeable levels of capacity. The statement demonstrates the ethical imperative and processes of recruiting adults across the capacity spectrum in varying populations and settings.

Associations between prenatal, childhood, and adolescent stress and variations in white-matter properties in young men

OBJECTIVE

Previous studies have shown that both pre- and post-natal adversities, the latter including exposures to stress during childhood and adolescence, explain variation in structural properties of white matter (WM) in the brain. While previous studies have examined effects of independent stress exposures within one developmental period, such as childhood, we examine effects of stress across development using data from a prospective longitudinal study. More specifically, we ask how stressful events during prenatal development, childhood, and adolescence relate to variation in WM properties in early adulthood in young men recruited from a birth cohort.

METHOD

Using data from 393 mother-son pairs from a community-based birth cohort from England (Avon Longitudinal Study of Parents and Children), we examined how stressful life events relate to variation in different structural properties of WM in the corpus callosum and across the whole brain in early adulthood in men aged 18-21 years. We distinguish between stress occurring during three developmental periods: a) prenatal maternal stress, b) postnatal stress within the first four years of life, c) stress during adolescence (age 12-16 years). To obtain a comprehensive quantification of variation in WM, we assess structural properties of WM using four different measures, namely fractional anisotropy (FA), mean diffusivity (MD), magnetization transfer ratio (MTR) and myelin water fraction (MWF).

RESULTS

The developmental model shows that prenatal stress is associated with lower MTR and MWF in the genu and/or splenium of the corpus callosum, and with lower MTR in global (lobar) WM. Stress during early childhood is associated with higher MTR in the splenium, and stress during adolescence is associated with higher MTR in the genu and lower MD in the splenium. We see no associations between postnatal stress and variation in global (lobar) WM.

CONCLUSIONS

The current study found evidence for independent effects of stress on WM properties during distinct neurodevelopmental periods. We speculate that these independent effects are due to differences in the developmental processes unfolding at different developmental time points. We suggest that associations between prenatal stress and WM properties may relate to abnormalities in neurogenesis, affecting the number and density of axons, while postnatal stress may interfere with processes related to myelination or radial growth of axons. Potential consequences of prenatal glucocorticoid exposure should be considered in obstetric care.

An excess of massive stars in the local 30 Doradus starburst

The 30 Doradus star-forming region in the Large Magellanic Cloud is a nearby analog of large star-formation events in the distant universe. We determined the recent formation history and the initial mass function (IMF) of massive stars in 30 Doradus on the basis of spectroscopic observations of 247 stars more massive than 15 solar masses ([Formula: see text]). The main episode of massive star formation began about 8 million years (My) ago, and the star-formation rate seems to have declined in the last 1 My. The IMF is densely sampled up to 200 [Formula: see text] and contains 32 ± 12% more stars above 30 [Formula: see text] than predicted by a standard Salpeter IMF. In the mass range of 15 to 200 [Formula: see text], the IMF power-law exponent is [Formula: see text], shallower than the Salpeter value of 2.35.

How many people will need palliative care in 2040? Past trends, future projections and implications for services

BACKGROUND

Current estimates suggest that approximately 75% of people approaching the end-of-life may benefit from palliative care. The growing numbers of older people and increasing prevalence of chronic illness in many countries mean that more people may benefit from palliative care in the future, but this has not been quantified. The present study aims to estimate future population palliative care need in two high-income countries.

METHODS

We used mortality statistics for England and Wales from 2006 to 2014. Building on previous diagnosis-based approaches, we calculated age- and sex-specific proportions of deaths from defined chronic progressive illnesses to estimate the prevalence of palliative care need in the population. We calculated annual change over the 9-year period. Using explicit assumptions about change in disease prevalence over time, and official mortality forecasts, we modelled palliative care need up to 2040. We also undertook separate projections for dementia, cancer and organ failure.

RESULTS

By 2040, annual deaths in England and Wales are projected to rise by 25.4% (from 501,424 in 2014 to 628,659). If age- and sex-specific proportions with palliative care needs remain the same as in 2014, the number of people requiring palliative care will grow by 25.0% (from 375,398 to 469,305 people/year). However, if the upward trend observed from 2006 to 2014 continues, the increase will be of 42.4% (161,842 more people/year, total 537,240). In addition, disease-specific projections show that dementia (increase from 59,199 to 219,409 deaths/year by 2040) and cancer (increase from 143,638 to 208,636 deaths by 2040) will be the main drivers of increased need.

CONCLUSIONS

If recent mortality trends continue, 160,000 more people in England and Wales will need palliative care by 2040. Healthcare systems must now start to adapt to the age-related growth in deaths from chronic illness, by focusing on integration and boosting of palliative care across health and social care disciplines. Countries with similar demographic and disease changes will likely experience comparable rises in need.

Reproducibility of Duplex Ultrasound in the Measurement of Venous Reflux

Objective:

To determine the reproducibility of duplex ultrasound in the measurement of reflux duration in lower limb veins.

Design:

Repeatability study.

Setting:

Vascular clinic in a tertiary referral centre.

Participants:

Twenty-one patients with severe venous disease.

Interventions:

Patients were scanned using duplex ultrasound by two of three observers, then rescanned by a different pair of observers after a mean interval of 51 days.

Main outcome measures:

Duration of venous reflux.

Results:

On a Wilcoxon signed rank test, observers 2 and 3 showed no significant interobserver variability. The other pairs of observers agreed at the majority of segments, but differed at the popliteal vein ( p≤0.001), and superficial femoral and common femoral veins ( p≤0.05). Observer 2 showed no significant intraobserver variability, but observer 1 differed at the common femoral and superficial femoral veins ( p≤0.05), and observer 3 differed at the short saphenous vein ( p≤0.05).

Conclusions:

Reproducibility was reasonable at certain sites, but appeared to be influenced by position of the vein.

Abstract P1-10-20: Importance of the patient voice in drug development: Early-stage breast cancer and measurement gaps concerning the treatment experience

Background: Most early-stage breast cancer (EBC) patients (pts) do not experience signs or symptoms of disease; approximately 90% of women diagnosed in breast screening are asymptomatic in the US (Ryerson et al. 2015). Rather, side effects of cancer therapy have the greatest impact and can be burdensome to pts on and after treatment. Bother and impact have not been thoroughly assessed from the patient perspective in trials. Qualitative research with 56 pts undergoing or completing (after 3 and within 24 mos of) systemic treatment were conducted to assess the need for EBC-focused patient-reported outcome (PRO) measures.

Methods: Semi-structured interviews were conducted to better understand the treatment experience; the interview guide was developed in consultation with breast cancer advocates who were former pts. The interview sample was determined to capture findings across EBC therapies (HER2-targeted [HER2], hormone/endocrine [H/E], and/or chemotherapy [CT]). Treatment experience, including treatment-related symptoms and treatment impact (e.g. on activities of daily living, emotional aspects) were discussed in each 90-minute session. Pts rated level of bother of symptoms and impacts on an 11-point scale. Disease stage, treatment received, surgery, and other health information was collected from medical charts. Qualitative analysis was conducted with ATLAS.ti software. Symptom data was reviewed to appropriately analyze therapy subgroups.

Results: Stage Ia (17.9%), Ib (14.3%), IIa (32.1%), IIb (25.0%), or IIIa (7.1%) pts that received adjuvant (75%) or neoadjuvant (25%) therapy participated; 106 unique treatment-related symptoms were reported. Symptoms most frequently reported included hair loss (86.7%), change in taste (73.3%), and tiredness/fatigue (71.1%) on CT (n=45); tiredness/fatigue (34.8%), runny nose (26.1%), and watery eyes (21.7%) on HER2 (n=23); and hot flashes (50.0%), joint pain (37.5%), and weight gain (20.1%) on H/E (n=24). The most common symptoms reported after therapy completion included memory loss (63.6%), symptoms of neuropathy (numbness, tingling, and pain in fingers, 63.6%), and tiredness/fatigue (45.5%) (n=11). CT symptoms rated by ≥ 25% of pts that were most bothersome included tiredness/fatigue (x -=8.2, n=18**), hair loss (x -=8.2, n=32**), and memory loss (x -=7.7, n=15**). HER2 and H/E ratings of bother were less frequent. EBC treatment was associated with significant impact on pts' lives; categories described are below:

Impact category Average bother rating* (n**)Concerns with treatment9.5 (2)Physical/functional7.7 (36)Work or school7.5 (37)Sleep7.5 (21)Daily tasks and activities7.4 (95)Emotional7.4 (62)Sexual behavior7.1 (22)Cognitive function6.8 (6)Social6.7 (54)Appearance6.5 (32)* Rating on 11-pt scale; 0=none to 10=extremely bothersome ** n=number of patients rating the level of bother

Conclusion: Treatment-related symptoms and associated degree of bother differed by treatment group. Pts' descriptions of treatment impact provided additional insight into the burden of EBC. EBC-specific PROs included in trials that gain pts' perspective on experience with treatment would further inform pts and may also inform therapy choice.

Citation Format: Petersen JA, Gauthier MA, Piault E, DeBusk KPA, Buzaglo JS, Eng-Wong J, Glazer JR, Green MC, Johnson JM, Spears PA, Evans CJ. Importance of the patient voice in drug development: Early-stage breast cancer and measurement gaps concerning the treatment experience. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-10-20.

Improved precision in CHARMED assessment of white matter through sampling scheme optimization and model parsimony testing

PURPOSE

The composite hindered and restricted model of diffusion provides microstructural indices that are potentially more specific than those from diffusion tensor imaging. However, in comparison to diffusion tensor imaging, the acquisition time is longer, limiting clinical applications. Moreover, the model requires several parameters to be estimated whose confidence intervals can be large. Here, the composite hindered and restricted model of diffusion acquisition and data processing pipelines are optimized to extend the utility of this approach.

METHODS

A multishell sampling scheme was optimized using the electrostatic repulsion algorithm, combined with optimal ordering. The optimal protocol, using as few measurements as possible, was determined through leave-n-out analyses. Parsimonious model selection criteria were used to select between nested models, comprising up to three restricted compartments. The schemes were evaluated using both through Monte-Carlo simulations and in vivo data.

RESULTS

The optimization/model selection procedure resulted in increased accuracy and precision on the estimated parameters, allowing for a reduction in acquisition time and marked improvements in data quality. The final protocol provided whole brain coverage data in only 12 min.

CONCLUSION

Through careful optimization of the acquisition and analysis pipeline for the composite hindered and restricted model of diffusion, it is possible to reduce acquisition time for whole brain datasets to a time that is clinically applicable.

Anti-nociception mediated by a κ opioid receptor agonist is blocked by a δ receptor agonist

BACKGROUND AND PURPOSE

The opioid receptor family comprises four structurally homologous but functionally distinct sub-groups, the μ (MOP), δ (DOP), κ (KOP) and nociceptin (NOP) receptors. As most opioid agonists are selective but not specific, a broad spectrum of behaviours due to activation of different opioid receptors is expected. In this study, we examine whether other opioid receptor systems influenced KOP-mediated antinociception.

EXPERIMENTAL APPROACH

We used a tail withdrawal assay in C57Bl/6 mice to assay the antinociceptive effect of systemically administered opioid agonists with varying selectivity at KOP receptors. Pharmacological and genetic approaches were used to analyse the interactions of the other opioid receptors in modulating KOP-mediated antinociception.

KEY RESULTS

Etorphine, a potent agonist at all four opioid receptors, was not anti-nociceptive in MOP knockout (KO) mice, although etorphine is an efficacious KOP receptor agonist and specific KOP receptor agonists remain analgesic in MOP KO mice. As KOP receptor agonists are aversive, we considered KOP-mediated antinociception might be a form of stress-induced analgesia that is blocked by the anxiolytic effects of DOP receptor agonists. In support of this hypothesis, pretreatment with the DOP antagonist, naltrindole (10 mg·kg(-1) ), unmasked etorphine (3 mg·kg(-1) ) antinociception in MOP KO mice. Further, in wild-type mice, KOP-mediated antinociception by systemic U50,488H (10 mg·kg(-1) ) was blocked by pretreatment with the DOP agonist SNC80 (5 mg·kg(-1) ) and diazepam (1 mg·kg(-1) ).

CONCLUSIONS AND IMPLICATIONS

Systemic DOP receptor agonists blocked systemic KOP antinociception, and these results identify DOP receptor agonists as potential agents for reversing stress-driven addictive and depressive behaviours mediated through KOP receptor activation.

LINKED ARTICLES

This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.

Incidence and risk factors for venous reflux in the general population: Edinburgh Vein Study

OBJECTIVE/BACKGROUND

Chronic venous disease (CVD) is common, but the incidence of venous reflux, a precursor to this condition, is unknown. This study measured the incidence of venous reflux and associated risk factors, and examined the association between venous reflux and the incidence of CVD.

METHODS

In the Edinburgh Vein Study, a random sample of 1566 men and women aged 18-64 years were examined at baseline. Eight hundred and eighty of these patients were followed up 13 years and underwent an examination comprising clinical classification of CVD and duplex scanning of the deep and superficial systems to measure venous reflux ≥0.5 s.

RESULTS

The 13-year incidence of reflux was 12.7% (95% confidence interval [CI] 9.2-17.2), equivalent to an annual incidence of 0.9% (95% CI 0.7-1.3). The 13-year incidence of isolated superficial, isolated deep, and combined deep and superficial reflux was 8.8% (95% CI 5.6-12.0), 2.6% (95% CI 1.2-5.0), and 1.3% (95% CI 0.4-3.2), respectively. The highest incidence was in the great saphenous vein in the lower thigh (8.1%, 95% CI 5.4-11.8). There were no age or sex differences (p > .050). The risk of developing reflux was associated with being overweight (odds ratio [OR] 2.1, 95% CI 1.0-4.4) and with history of deep vein thrombosis (OR 11.3, 95% CI 1.0-132.3). Venous reflux at baseline was associated with new varicose veins at follow up (p < .001): the age- and sex-adjusted OR was 4.4 (95% CI 1.8-10.8) in those with isolated superficial reflux and 7.3 (95% CI 2.6-22.5) in those with combined deep and superficial reflux.

CONCLUSION

For every year of follow-up, around 1% of this adult population developed venous reflux. In two thirds of cases, the superficial system was affected. Venous reflux increased the risk of developing varicose veins, especially when combined deep and superficial reflux was present.

Validation study of the Self-Assessment Goal Achievement (SAGA) questionnaire for lower urinary tract symptoms

BACKGROUND

Patients' treatment goals for overactive bladder (OAB) and other lower urinary tract symptoms (LUTS) may not be aligned with their healthcare provider's goals. Successful management of OAB symptoms is improved by individualised treatment plans with attainable treatment goals. Goal attainment setting may facilitate patient-provider interaction and the development of a personalised treatment plan based on realistic, individual goals, thereby increasing patient satisfaction and therapeutic outcomes. The purpose of this study was to validate the utility of the Self-Assessment Goal Achievement (SAGA) questionnaire for LUTS in helping patients identify and achieve realistic treatment goals.

METHODS

The 2-module SAGA questionnaire consists of nine prespecified (fixed) items and five open-ended items for goal identification and ranking (baseline module) and goal achievement rating (follow-up module). Adult patients in the United States (n = 104) seeking treatment for LUTS, including symptoms of OAB, completed the SAGA baseline module, micturition diary, other patient-reported outcome measures (PROs), and discussed their urinary goals with a clinician at baseline. The SAGA follow-up module was completed 2-4 months later. SAGA was validated based on analyses of face, concurrent, known-groups, and convergent validity and item distribution.

RESULTS

Among the nine fixed goals of SAGA, four were ranked as very important by > 50% of patients (i.e. reduce night-time frequency, daytime frequency, urine leakage, urgency). Most patients did not change the importance level of their goals after discussion with their healthcare provider. Pearson correlations between SAGA, diary variables and PRO scores were generally of low to moderate strength. The global mean (SD) follow-up SAGA T-score was 32.54 (12.54), indicating that overall goal attainment was not achieved after 3 months. The goal attainment score was significantly different between groups differing in symptom severity, health-related quality of life, bladder control and continence status.

CONCLUSIONS

The results support the validity of SAGA as a measure of patients' goals and goal achievement for the treatment of LUTS, including symptoms of OAB. SAGA may improve healthcare provider-patient interactions and treatment outcomes in clinical practice.

Telangiectasia and venous reflux in the Edinburgh Vein Study

Objective

The purpose of this study was to correlate the clinical findings in the Edinburgh Vein Study with the results of duplex scanning of the deep and superficial venous systems.

Methods

An age-stratified random sample of 1566 people (699 men and 867 women) aged 16–64 were selected from computerized age–sex registers of participating practices (twelve general practices with catchment areas geographically and socioeconomically distributed throughout Edinburgh). Screening included clinical examination, photography and duplex ultrasonography of the superficial veins and the deep veins down to popliteal level. Telangiectasia and varicose veins were graded 1–3 according to severity.

Results

Since there was good agreement between the duplex findings of the right versus left legs, the current analyses are based on 1092 subjects (486 men and 606 women) with complete duplex scan data in their left legs. There was no significant trend of increasing incompetence in either the deep veins only ( P = 0.214) or in the combined deep and superficial veins ( P = 0.111) with increasing severity of the telangiectasia. There was a statistically significant trend for increasing incompetence in (a) the superficial veins ( P = 0.006) and (b) either the superficial or deep veins ( P < 0.001) to be associated with advancing grade of telangiectasia. When stratified by gender, significant trends were maintained for male superficial vein incompetence and for either superficial or deep incompetence in both genders. Examination of incompetence in individual venous segments showed that increasing severity of telangiectasia was significantly associated with an increasing proportion of reflux in the upper and lower great saphenous and femoral vein segments. There was no significant association between small saphenous incompetence and increasing grade of telangiectasia.

Conclusion

There is a significant, but not wholly consistent, association between grade of telangiectasia and reflux in both the deep and superficial systems. This association does not apply to the small saphenous system.

Binary interaction dominates the evolution of massive stars

The presence of a nearby companion alters the evolution of massive stars in binary systems, leading to phenomena such as stellar mergers, x-ray binaries, and gamma-ray bursts. Unambiguous constraints on the fraction of massive stars affected by binary interaction were lacking. We simultaneously measured all relevant binary characteristics in a sample of Galactic massive O stars and quantified the frequency and nature of binary interactions. More than 70% of all massive stars will exchange mass with a companion, leading to a binary merger in one-third of the cases. These numbers greatly exceed previous estimates and imply that binary interaction dominates the evolution of massive stars, with implications for populations of massive stars and their supernovae.

The effect of improved modelling of plasma clearance in paediatric patients with expanded body spaces on estimation of the glomerular filtration rate

The glomerular filtration rate (GFR) is used clinically to assess renal function. The most accurate estimation technique is tracer clearance where deterministic compartment pharmacokinetic models are most widely used. The aim of this study was to assess the viability of alternative pharmacokinetic models to describe tracer clearance, and in turn, measure GFR. This study was carried out on 126 clearance datasets obtained from 44 patients with large solid tumours; these were fitted to four pharmacokinetic models with superiority of model determined by Akaike Information Criteria. A fractal model was found to be superior to the best deterministic compartment model (70% of datasets, P < 0.0020) as was a gamma-distributed residence time model (93% of datasets, P < 0.0020); both models also gave greater mean weighted coefficients of determination than deterministic compartment models. These results suggest that gamma-distributed residence time and fractal models better describe tracer clearance than deterministic compartment models and therefore should allow more accurate estimation of GFR.

Malaysian participation in the IAEA/WHO postal TLD and postal ionisation chamber intercomparison programmes: analysis of results obtained during 1985-2008

During the years 1985-2008, the Secondary Standards Dosimetry Laboratory of Malaysia (SSDL Malaysia) has participated 37 times in the IAEA/WHO intercomparison programmes. This paper reports an analysis of the intercomparison data and demonstrates that the quality of the SSDL calibration service is well within the limits required by IAEA.

A mathematical model of doxorubicin penetration through multicellular layers

Inadequate drug delivery to tumours is now recognised as a key factor that limits the efficacy of anticancer drugs. Extravasation and penetration of therapeutic agents through avascular tissue are critically important processes if sufficient drug is to be delivered to be therapeutic. The purpose of this study is to develop an in silico model that will simulate the transport of the clinically used cytotoxic drug doxorubicin across multicell layers (MCLs) in vitro. Three cell lines were employed: DLD1 (human colon carcinoma), MCF7 (human breast carcinoma) and NCI/ADR-Res (doxorubicin resistant and P-glycoprotein [Pgp] overexpressing ovarian cell line). Cells were cultured on transwell culture inserts to various thicknesses and doxorubicin at various concentrations (100 or 50 microM) was added to the top chamber. The concentration of drug appearing in the bottom chamber was determined as a function of time by HPLC-MS/MS. The rate of drug penetration was inversely proportional to the thickness of the MCL. The rate and extent of doxorubicin penetration was no different in the presence of NCI/ADR-Res cells expressing Pgp compared to MCF7 cells. A mathematical model based upon the premise that the transport of doxorubicin across cell membrane bilayers occurs by a passive "flip-flop" mechanism of the drug between two membrane leaflets was constructed. The mathematical model treats the transwell apparatus as a series of compartments and the MCL is treated as a series of cell layers, separated by small intercellular spaces. This model demonstrates good agreement between predicted and actual drug penetration in vitro and may be applied to the prediction of drug transport in vivo, potentially becoming a useful tool in the study of optimal chemotherapy regimes.

Mu opioid receptor-effector coupling and trafficking in dorsal root ganglia neurons

Morphine induces profound analgesic tolerance in vivo despite inducing little internalization of the mu opioid receptor (muOR). Previously proposed explanations suggest that this lack of internalization could either lead to prolonged signaling and associated compensatory changes in downstream signaling systems, or that the receptor is unable to recycle and resensitize and so loses efficacy, either mechanism resulting in tolerance. We therefore examined, in cultured neurons, the relationship between muOR internalization and desensitization in response to two agonists, D-Ala2, N-MePhe4, Gly5-ol-enkephalin (DAMGO) and morphine. In addition, we studied the chimeric mu/delta opioid receptor (mu/ partial differentialOR) which could affect internalization and desensitization in neurons. Dorsal root ganglia neurons from muOR knockout mice were transduced with an adenovirus expressing either receptor and their respective internalization, desensitization and trafficking profiles determined. Both receptors desensitized equally, measured by Ca2+ current inhibition, during the first 5 min of agonist exposure to DAMGO or morphine treatment, although the mu/partial differentialOR desensitized more extensively. Such rapid desensitization was unrelated to internalization as DAMGO, but not morphine, internalized both receptors after 20 min. In response to DAMGO the mu/partial differentialOR internalized more rapidly than the muOR and was trafficked through Rab4-positive endosomes and lysosomal-associated membrane protein-1-labeled lysosomes whereas the muOR was trafficked through Rab4 and Rab11-positive endosomes. Chronic desensitization of the Ca2+ current response, after 24 h of morphine or DAMGO incubation, was seen in the DAMGO, but not morphine-treated, muOR-expressing cells. Such persistence of signaling after chronic morphine treatment suggests that compensation of downstream signaling systems, rather than loss of efficacy due to poor receptor recycling, is a more likely mechanism of morphine tolerance in vivo. In contrast to the muOR, the mu/partial differentialOR showed equivalent desensitization whether morphine or DAMGO treated, but internalized further with DAMGO than morphine. Such ligand-independent desensitization could be a result of the observed higher rate of synthesis and degradation of this chimeric receptor.

Gamma camera scintigraphy of tumours using195mPt-cisplatin

Platinum enriched with 194Pt was irradiated for 4 days in NRG's TIRO 1 reactor, to produce (195m)Pt. Spectral analysis of the product was performed using a calibrated hyper pure germanium detector and its constituent radioisotopes were identified as (195m)Pt, 199Au and 192Ir. Using the detector's intrinsic efficiency calibration, their activities were estimated to be 1049, 133 and 5.8 MBq, respectively. The performance of the gamma camera was tested using quality control procedures recommended by the Institute of Physics and Engineering in Medicine (IPEM) and was found to be satisfactory. A torso phantom was used to determine the minimum detection limit (MDL) of (195m)Pt in a 2 cm diameter tumour using SPECT acquisitions (32 steps, 60 s per step). The MDL was found to be 8 ppm assuming an administered patient dose of 50 MBq and a total cisplatin dose of 105 mg. This work indicates that (195m)Pt-cisplatin is suitable for clinical scintigraphy and has led to the development of a clinical protocol that has been approved for a pilot study.

Do real time 'flu spotter rates warn us about impending emergency admissions and deaths?

This study aimed to determine how general practice influenza surveillance ('flu spotter) data related to hospital admissions and deaths in Scotland during the winter period. 'Flu spotter rates correlated well with influenza-related emergency admissions and deaths, and deaths from all causes, particularly during 'peak' influenza years. They may be used in a predictive model for influenza-related hospital admissions and deaths.

Functional coupling, desensitization and internalization of virally expressed mu opioid receptors in cultured dorsal root ganglion neurons from mu opioid receptor knockout mice

Although mu opioid receptors desensitize in various cell lines in vitro, the relationship of this change in signaling efficacy to the development of tolerance in vivo remains uncertain. It is clear that a system is needed in which functional mu opioid receptor expression is obtained in appropriate neurons so that desensitization can be measured, manipulated, and mutated receptors expressed in this environment. We have developed a recombinant system in which expression of a flag-tagged mu opioid receptor is returned to dorsal root ganglia neurons from mu opioid receptor knockout mice in vitro. Flow cytometry analysis showed that adenoviral-mediated expression of the amino-terminal flag-tagged mu opioid receptor in neurons resulted in approximately 1.3x10(6) receptors/cell. Many mu opioid receptor cell lines express a similar density of receptors but this is approximately 7x greater than the number of endogenous receptors expressed by matched wild-type neurons. Inhibition of the high voltage-activated calcium currents in dorsal root ganglia neurons by the mu agonist, D-Ala(2), N-MePhe(4), Gly(5)-ol-enkephalin (DAMGO), was not different between the endogenous and flag-tagged receptor at several concentrations of DAMGO used. Both receptors desensitized equally over the first 6 h of DAMGO pre-incubation, but after 24 h the response of the endogenous receptor to DAMGO had desensitized further than the flag- tagged receptor (71+/-3 vs 29+/-7% respectively; P<0.002), indicating less desensitization in neurons expressing a higher density of receptor. Using flow cytometry to quantify the percentage of receptors remaining on the neuronal cell surface, the flag-tagged receptor internalized by 17+/-1% after 20 min and 55+/-2% after 24 h of DAMGO. These data indicate that this return of function model in neurons recapitulates many of the characteristics of endogenous mu opioid receptor function previously identified in non-neuronal cell lines.

A mathematical model of CO2 variation in the ventilated neonate

A mathematical model of the variation of partial pressure of carbon dioxide in the arterial blood of a ventilated neonate is developed. The model comprises alveolar, arterial, pulmonary, venous and tissue compartments, with gas exchange in the lung determined by inspiration and expiration terms. Gas exchange is modelled through diffusion and convective transfer. Carbon dioxide is produced in the tissue by a metabolic term. Shunting is modelled by allowing blood flow to bypass the pulmonary compartment in which diffusion takes place. The model predicts changes in the carbon dioxide partial pressures that occur following abrupt changes in the ventilation settings, and show broad agreement with actual data obtained from novel sensing technology.

The specific absorbed dose constant: comparison of values published for 60Co photons

For the specific absorbed dose constant for 60Co photons, three values quoted directly in the literature and two derived indirectly from published information are reported. The three publications giving the direct values mentioned no medium of absorption, whereas the other two specify tissue. A database of the specific absorbed dose constant is generated for each of 14 media namely air, water, bone and 11 types of soft tissue. These values are consistent with the three directly quoted values plus one of the indirectly obtained values. Air is found to be unlikely as the medium for the first three; and appropriate media for these are suggested. For the other two values, the generated database suggests that one is too small to be accurate; while the other is correct for tissue (as stated in the publication). An apparent error of 10(3) is identified in one of the values directly quoted.

Relationship between lower limb symptoms and patterns of deep and superficial venous reflux on duplex ultrasonography

Background

There are inconsistent and sex-dependent relationships between lower limb symptoms and the presence and severity of trunk varicose veins on clinical examination. The relationship between lower limb symptoms and patterns of venous reflux on duplex ultrasonography were investigated.

Methods

This was a cross-sectional study of an age-stratified random sample of 1566 subjects (699 men and 867 women) aged 18–64 years selected from 12 family practices. Subjects completed a self-administered questionnaire regarding symptoms (heaviness/tension, a feeling of swelling, aching, restless legs, cramps, itching, tingling) and underwent duplex ultrasonographic examination of both legs. Reflux greater than 0·5 s was considered pathological.

Results

Isolated superficial reflux was significantly related to the presence of heaviness/tension (P &lt; 0·025, both legs) and itching (P = 0·002, left leg only) in women. Isolated deep venous reflux was not significantly related to any symptom in either leg in either sex. Combined superficial and deep reflux was related to a feeling of swelling (P = 0·02, both legs), cramps (P &lt; 0·005, left leg only) and itching (P &lt; 0·005, left leg only) in men, and aching (P = 0·03, right leg only) and cramps (P = 0·026, left leg only) in women.

Conclusion

Duplex ultrasonography may be superior to clinical examination alone in identifying patients whose lower limb symptoms are truly of venous origin and thus most likely to benefit from surgery.

Chronic venous insufficiency in the general population: clinical and duplex correlations

Background

If operations for chronic venous insufficiency (CVI) are to be rational and cost effective, the natural history needs to be understood and patients with early disease who will progress to advanced CVI and leg ulcer need to be identified. Published data have derived largely from selected referred hospital patients. The pattern of venous disease in the general population is unknown. The aim was to determine the prevalence of CVI in the general population and to correlate clinical features with the findings on duplex ultrasonography.

Methods

A cross-section of men and women aged 18–64 years randomly selected from 12 general practices were surveyed. Subjects were screened by questionnaire, examination, photography, blood tests and continuous-wave Doppler ultrasonography. Eight segments of the deep and superficial veins were assessed for reflux by means of duplex ultrasonography.

Results

Some 1566 patients were screened (867 women of mean age 44·8 years and 699 men of mean age 45·8 years), of whom 134 were diagnosed as having CVI (Basle classification): grade 1, 95; grade 2, 19; grade 3, ten. The age-adjusted prevalence for the whole series was 3·1 per cent (2·6 per cent in men, 3·4 per cent in women). The prevalence of CVI correlated closely with age, being 15·2 per cent in men aged over 50 years and 9·0 per cent in women aged above 50 years. Heaviness, tension, swelling, aching and itching were significantly commoner in patients with CVI than in the general population. CVI was significantly associated with reflux in all deep and superficial segments. The frequency of reflux in both superficial and deep segments increased with the clinical severity of disease (P = 0·01). In 48·1 per cent reflux was limited to the superficial system and was thus potentially remediable.

Conclusion

CVI was common in this relatively young population. Having established the frequency of CVI and its related pattern of reflux in the general population, this cohort provides a benchmark for clinical studies and will form the basis of further longitudinal epidemiological studies.

The use of associated particle timing based on the D + D reaction for imaging a solid object

Associated particle timing based on the D + D reaction has been applied for imaging a bulk sample, namely an aluminium box. The relatively low neutron energy, 2.8 MeV, allows a better spatial resolution from time-of-flight measurements. A combination of a Si detector for charged particles and an NaI(Tl) scintillator for inelastic-scatter gamma rays yielded an overall time resolution of 0.4 ns, giving a spatial resolution of better than 1 cm. A new reconstruction program was developed, yielding an image free from major artefacts.

Pure rotational spectra, structures, and hyperfine constants of OC-AuX (X = F, Cl, Br)

Rotational spectra of OC-AuX (X = F, Cl, Br) have been measured in the frequency range 5-21 GHz, using a pulsed jet cavity Fourier transform microwave spectrometer. The molecules were prepared by ablating Au metal with a Nd:YAG laser and allowing the vapor to react with CO plus a halide precursor contained in the Ar backing gas of the jets. For OC-AuCl and OC-AuBr these are the first high-resolution spectroscopic measurements; for OC-AuF these are the first observations of any kind. All three molecules are linear. Rotational constants, centrifugal distortion constants, and nuclear quadrupole coupling constants have been precisely evaluated. The geometries determined for all three molecules show CO bond lengths close to that of free CO, plus relatively long Au-C bonds. These results are corroborated by ab initio calculations, which have also produced Mulliken populations showing significant sigma-donation from CO to Au, plus some pi-back-donation from Au to CO. There are major changes in the Au, Cl, and Br nuclear quadrupole coupling constants when CO bonds to AuX, consistent with the formation of strong Au-C bonds. The structural properties of OC-AuF are somewhat different from those of OC-AuCl and OC-AuBr.

An economic evaluation of a chlorhexidine chip for treating chronic periodontitis: the CHIP (chlorhexidine in periodontitis) study

BACKGROUND

The authors previously suggested that an adjunctive, controlled-release chlorhexidine, or CHX, chip may reduce periodontal surgical needs at little additional cost. This article presents an economic analysis of the CHX chip in general dental practice.

METHODS

In a one-year prospective clinical trial, 484 chronic periodontitis patients in 52 general practices across the United States were treated with either scaling and root planing, or SRP, plus any therapy prescribed by treating, unblinded dentists; or SRP plus other therapy as above but including the CHX chip. Economic data were collected from bills, case report forms and 12-month treatment recommendations from blinded periodontist evaluators.

RESULTS

Total dental charges were higher for SRP + CHX chip patients vs. SRP patients when CHX chip costs were included (P = .027) but lower when CHX chip costs were excluded (P = .012). About one-half of the CHX chip acquisition cost was offset by savings in other charges. SRP + CHX chip patients were about 50 percent less likely to undergo surgical procedures than were SRP patients (P = .021). At the end of the trial, periodontist evaluators recommended similar additional procedures for both groups: SRP, about 46 percent; maintenance, about 37 percent; surgery, 56 percent for SRP alone and 63 percent for SRP + CHX chip.

CONCLUSIONS

Adjunctive CHX chip use for general-practice patients with periodontitis increased costs but reduced surgeries over one year. At study's end, periodontists recommended similar additional surgical treatment for both groups.

CLINICAL IMPLICATIONS

In general practice, routine use of the CHX chip suggests that costs will be partially offset by reduced surgery over at least one year.

Disruption of the Crithidia fasciculata KAP1 gene results in structural rearrangement of the kinetoplast disc

The mitochondrial DNA (kinetoplast DNA) in trypanosomatids exists as a highly organized nucleoprotein structure with the DNA consisting of thousands of interlocked circles. Four H1 histone-like proteins (KAP1, 2, 3 and 4) are associated with the kinetoplast DNA in the trypanosomatid Crithidia fasciculata. We have disrupted both alleles of the KAP1 gene in this diploid protozoan and shown that expression of the KAP1 protein is eliminated. The mutant strain is viable but has substantial rearrangement of the kinetoplast structure. Expression of the KAP1 protein from an episome restored expression of the KAP1 protein in the mutant strain and also restored a normal kinetoplast structure. These studies provide evidence that the KAP1 protein is involved in kinetoplast DNA organization in vivo but is nonessential for cell viability.

Agonist-, antagonist-, and inverse agonist-regulated trafficking of the delta-opioid receptor correlates with, but does not require, G protein activation

In this study, we explored the relationship between ligand-induced regulation of surface delta opioid receptors and G protein activation. G protein activation was assessed with [(35)S]guanosine-5'-O-(3-thio)triphosphate (GTP gamma S) binding assays conducted at both 37 and 0 degrees C. Ligand-independent (constitutive) activity of the delta-receptor was readily observed when the [(35)S]GTP gamma S binding assay was performed at 37 degrees C. We identified a new class of alkaloid inverse agonists (RTI-5989-1, RTI-5989-23, RTI-5989-25), which are more potent than the previously described peptide inverse agonist ICI-174864 (N,N-diallyl-Tyr-Aib-Aib-Phe-Leu). Treatment with these inverse agonists for 18 h caused up-regulation of surface receptors. Eighteen-hour treatment with etorphine resulted in approximately 90% loss of surface receptor, whereas fentanyl, diprenorphine, and morphine caused between 20 and 50% loss. The abilities of ligands to modulate [(35)S]GTP gamma S binding at 37 degrees C showed a strong correlation with their abilities to regulate surface receptor number (r(2) = 0.86). Interestingly, the ability of fentanyl to activate G proteins was markedly temperature sensitive. Fentanyl showed no stimulation of [(35)S]GTP gamma S binding at 0 degrees C but was as efficacious as etorphine, morphine, and diprenorphine at 37 degrees C. Neither the ligand-induced receptor increases nor decreases were perturbed by pertussis toxin pretreatment, suggesting that functional G proteins are not required for ligand-regulated delta-opioid receptor trafficking.

Prevalence and risk factors of chronic venous insufficiency

Venous disease in the legs occurs very commonly in the general population in Western countries. Around one third of women have trunk varices. A lower prevalence has been observed in men but some recent surveys have suggested that the occurrence in men may be comparable to that in women. The prevalence increases with age but the incidence of new cases appears to be constant throughout adult life. Open venous ulcers occur in about 0.3% of the adult population and a history of open or healed ulceration occurs in around 1%. The etiology of chronic venous disease in the legs is unknown. A genetic predisposition may be present but evidence for this and for a mode of inheritance is lacking. There is some suggestion that prolonged standing may be a risk factor but studies are open to considerable bias. In women, obesity and previous pregnancy has been associated with the presence of varicose veins but the evidence is inconsistent. There have been few well-conducted studies examining diet and bowel habit as a risk factor. The risk of ulceration is related to the severity of varicosities and venous insufficiency, and is increased following deep vein thrombosis. Much further research is required to investigate the cause of this common condition in the general population.

Lifestyle risk factors for lower limb venous reflux in the general population: Edinburgh Vein Study

BACKGROUND

Varicose veins occur commonly in the general population but the aetiology is not well established. Varicosities are associated frequently with reflux of blood in the leg veins due to valvular incompetence. Our aim was to determine in the general population which lifestyle factors were related to reflux and thus implicated in the aetiology of varicose veins.

METHODS

In the Edinburgh Vein Study, 1566 men and women aged 18-64 years were sampled randomly from the general population in the city of Edinburgh, Scotland, and had duplex scans to measure reflux in eight venous segments in each leg. A self-administered questionnaire enquired about occupation, mobility at work, smoking, obstetric history, dietary fibre intake and bowel habit. A bowel record form was completed subsequently.

RESULTS

In women, venous reflux was associated with decreased sitting at work (odds ratio [OR] = 0.76, 95% CI : 0.61-0.94), previous pregnancy (OR = 1.20, 95% CI : 0.93-1.54), and a lower prior use of oral contraceptives (OR = 0.84, 95% CI : 0.66-1.06). Mean body mass index was greater in women with superficial reflux compared to those with no reflux: 26.2 kg/m(2) (95% CI : 25.5-27.0) versus 25.2 kg/m(2) (95% CI : 24.8-25.6). On age adjustment, sitting at work remained related to reflux (OR = 0.78, 95% CI : 0.63-0.98) and prior use of oral contraceptives to superficial reflux (OR = 0.71, 95% CI : 0.50-1.01). In age-adjusted analyses in men, height was related to reflux, (OR = 1.13, 95% CI : 1.02-1.26) and straining at stool was related to superficial reflux (OR = 1.94, 95% CI : 1.12-3.35). No associations were found in either sex between reflux and social class, lifetime cigarette consumption, dietary fibre intake and intestinal transit time.

CONCLUSIONS

This population study did not identify strong and consistent lifestyle risk factors for venous reflux although previous pregnancy, lower use of oral contraceptives, obesity and mobility at work in women and height and straining at stool in men may be implicated.

Differential splicing of transcripts encoding the orphanin FQ/nociceptin precursor

Orphanin FQ or nociceptin (OFQ/N), the heptadecapeptide agonist for the NOP receptor, is derived by proteolytic processing from a precursor protein, preproOFQ/N. Previous studies have reported alternative splicing between exons 3 and 4 of the mouse OFQ/N transcript, which, upon translation, would yield precursor proteins with different C-termini. Using RT-PCR, we identified similar alternative splicing of preproOFQ/N transcripts in humans and rats. In addition, we identified two novel human preproOFQ/N splice variants from which exon 2 has been excised and which also undergo alternative splicing between exons 3 and 4. Exon 2 contains the translational start site for preproOFQ/N and encodes the signal peptide sequence. In vitro translation of cRNAs lacking exon 2 yields shorter translation products which arise from an alternative initiator methionine located within exon 3. The resulting proteins would lack a signal peptide sequence, which would likely alter their cellular trafficking and processing.

Fiber intake, constipation, and risk of varicose veins in the general population: Edinburgh Vein Study

The purpose of the present study was to determine the relationship between fiber intake, constipation, and clinical venous disease in the general population. The Edinburgh Vein Study was comprised of 1566 men and women aged 18-64 years who were selected at random from the age-sex registers of 12 general practices. Fiber intake, intestinal transit time, defecation frequency and the prevalence of straining at stool were all found to be significantly different between the sexes. Men who reported that they strained to start passing a motion showed a higher prevalence of mild and severe trunk varices compared to men who did not strain. After adjustment for social class, BMI and mobility at work, this group of men showed a significantly elevated risk of having severe trunk varices (OR 2.76, 95% CI 1.16, 6.58). In contrast, no consistent relationships were seen among women. Overall, within this Western general population, an association between dietary fiber, constipation and the presence or severity of varicose veins was not supported.

Expression of MsLEC1- and MsLEC2-antisense genes in alfalfa plant lines causes severe embryogenic, developmental and reproductive abnormalities

Although it has been proposed that plant lectins play a number of roles, the function of these proteins in normal plant growth and development has been unclear. To analyze the functions of putative alfalfa lectin genes, lines of transgenic alfalfa plants expressing approximately half of the open reading frame of MsLEC1 or MsLEC2, in the antisense or sense orientation, were established and analyzed. The antisense plants displayed severe abnormalities in embryogenesis, and both vegetative and reproductive development were perturbed. Some differences were observed between MsLEC1- and MsLEC2-antisense plants, and abnormalities were especially severe during the early stages of development in both the primary and secondary transgenic generations. In contrast, vector-control and sense-transgene plants exhibited normal growth and development. MsLEC1 and MsLEC2 mRNA accumulation levels were reduced in cognate antisense plants, especially during the later stages of embryogenesis, but also tended to be low in MsLEC1 sense-transgene plants. However, correlated with the phenotypic abnormalities observed in the MsLEC1-antisense plants was the specific reduction in the accumulation of a candidate MsLEC1 protein. Our results suggest that the MsLEC1 and MsLEC2 gene products, in addition to being important for embryogenesis, are required throughout alfalfa development.

Neurotrophin dependence domain: a domain required for the mediation of apoptosis by the p75 neurotrophin receptor

The mechanisms underlying neurotrophin dependence, and cellular dependent states in general, are unknown. We show that a 29 amino acid region in the intracellular domain of the common neurotrophin receptor, p75NTR, is required for the mediation of apoptosis by p75NTR. Furthermore, contrary to results obtained with Fas, monomeric p75NTR is required for apoptosis induction, whereas multimerization inhibits the pro-apoptotic effect. Within the 29-residue domain required for apoptosis induction by p75NTR, a 14-residue region is sufficient as a peptide inducer of apoptosis. This 14-residue peptide requires the positively charged carboxyterminal residues for its effect on cell death, and these same residues are required by the full-length p75NTR. These studies define a novel type of domain that mediates neurotrophin dependence, and suggest that other cellular dependent states may be mediated by proteins displaying similar domains.

Hyperfine Structure in the Rotational Spectrum of GaF: A Comparison of Experimental and Calculated Spin-Rotation and Electric Field Gradient Tensors

The high-resolution pure rotational spectrum of GaF has been measured using a Balle-Flygare-type Fourier transform spectrometer. Improved nuclear quadrupolar coupling constants and rotational constants have been obtained along with the first reported fluorine spin-rotation constant for gallium fluoride, C(I) ((69)Ga(19)F, v = 0) = +32.0(21) kHz. Accurate spin-rotation tensors from microwave or molecular beam spectroscopy are particularly important to NMR spectroscopists and theoreticians because these data provide information about anisotropic nuclear magnetic shielding in the absence of intermolecular effects. For quadrupolar nuclei such as gallium, the quadrupolar interaction is sufficiently large that it is very difficult to characterize shielding tensors directly via NMR spectroscopy. The experimentally determined nuclear quadrupolar coupling constants and spin-rotation constants for GaF are compared with the results of a series of high-level ab initio calculations carried out at various levels of theory with a range of basis sets. Further calculations on BF and AlF, supplemented with available experimental data for InF and TlF, allow for the investigation of trends in nuclear magnetic shielding, spin-rotation, and electric field gradient tensors in the group-13 fluorides. Calculations at the MP2/6-311++G** and MP2/6-311G(2df, 2pd) levels provide the most consistently satisfactory results in comparison with the experimental data. Copyright 2000 Academic Press.

Patterns of reflux and severity of varicose veins in the general population--Edinburgh Vein Study

OBJECTIVES

several studies have used duplex ultrasound to assess valvular incompetence in symptomatic patients. This cross-sectional survey was performed to determine, for the first time in a general population sample, the relationship between trunk varices and the presence of reflux in lower limb venous segments.

MATERIALS AND METHODS

1238 subjects (554 male, 684 female), aged 18-64 years, were randomly selected. The presence and severity of any trunk varices was assessed and classified into Grades 1-3; hyphenweb and reticular varices were noted. The presence or absence of reflux > or = 0.5 s in five deep and three superficial venous segments in each leg was assessed using duplex ultrasound.

RESULTS

the prevalence of reflux increased in both superficial and deep segments with more severe grades of trunk varices (p< or = 0.01), except the upper SFV in women. Fifteen per cent of females showed reflux confined to the superficial system, compared with 9% of males (p< or = 0.001); 22% of males showed deep reflux, compared with 11% of females (p < or = 0.001). 71% of men and 48% of women with Grade 2-3 trunk varices had mixed deep and superficial reflux. Above-knee popliteal segments had a higher prevalence of reflux than lower SFV segments in all groups. There was no consistent relationship between the presence of hyphenweb or reticular varices and deep or superficial reflux.

CONCLUSION

segmental venous reflux can be detected in the deep and superficial leg veins of subjects without trunk varices, but superficial and mixed reflux are increasingly found in subjects with more severe varices.