Uterine-Artery Embolization or Myomectomy for Uterine Fibroids.

BACKGROUND: Uterine fibroids, the most common type of tumor among women of reproductive age, are associated with heavy menstrual bleeding, abdominal discomfort, subfertility, and a reduced quality of life. For women who wish to preserve their uterus and who have not had a response to medical treatment, myomectomy and uterine-artery embolization are therapeutic options. METHODS: We conducted a multicenter, randomized, open-label trial to evaluate myomectomy, as compared with uterine-artery embolization, in women who had symptomatic uterine fibroids and did not want to undergo hysterectomy. Procedural options included open abdominal, laparoscopic, or hysteroscopic myomectomy. The primary outcome was fibroid-related quality of life, as assessed by the score on the health-related quality-of-life domain of the Uterine Fibroid Symptom and Quality of Life (UFS-QOL) questionnaire (scores range from 0 to 100, with higher scores indicating a better quality of life) at 2 years; adjustment was made for the baseline score. RESULTS: A total of 254 women, recruited at 29 hospitals in the United Kingdom, were randomly assigned: 127 to the myomectomy group (of whom 105 underwent myomectomy) and 127 to the uterine-artery embolization group (of whom 98 underwent embolization). Data on the primary outcome were available for 206 women (81%). In the intention-to-treat analysis, the mean (±SD) score on the health-related quality-of-life domain of the UFS-QOL questionnaire at 2 years was 84.6±21.5 in the myomectomy group and 80.0±22.0 in the uterine-artery embolization group (mean adjusted difference with complete case analysis, 8.0 points; 95% confidence interval [CI], 1.8 to 14.1; P = 0.01; mean adjusted difference with missing responses imputed, 6.5 points; 95% CI, 1.1 to 11.9). Perioperative and postoperative complications from all initial procedures, irrespective of adherence to the assigned procedure, occurred in 29% of the women in the myomectomy group and in 24% of the women in the uterine-artery embolization group. CONCLUSIONS: Among women with symptomatic uterine fibroids, those who underwent myomectomy had a better fibroid-related quality of life at 2 years than those who underwent uterine-artery embolization. (Funded by the National Institute for Health Research Health Technology Assessment program; FEMME Current Controlled Trials number, ISRCTN70772394.).

Convection in a volatile nitrogen-ice-rich layer drives Pluto's geological vigour.

The vast, deep, volatile-ice-filled basin informally named Sputnik Planum is central to Pluto's vigorous geological activity. Composed of molecular nitrogen, methane, and carbon monoxide ices, but dominated by nitrogen ice, this layer is organized into cells or polygons, typically about 10 to 40 kilometres across, that resemble the surface manifestation of solid-state convection. Here we report, on the basis of available rheological measurements, that solid layers of nitrogen ice with a thickness in excess of about one kilometre should undergo convection for estimated present-day heat-flow conditions on Pluto. More importantly, we show numerically that convective overturn in a several-kilometre-thick layer of solid nitrogen can explain the great lateral width of the cells. The temperature dependence of nitrogen-ice viscosity implies that the ice layer convects in the so-called sluggish lid regime, a unique convective mode not previously definitively observed in the Solar System. Average surface horizontal velocities of a few centimetres a year imply surface transport or renewal times of about 500,000 years, well under the ten-million-year upper-limit crater retention age for Sputnik Planum. Similar convective surface renewal may also occur on other dwarf planets in the Kuiper belt, which may help to explain the high albedos shown by some of these bodies.

Study protocol: optical coherence tomography angiography for the detection of neovascular age-related macular degeneration: a comprehensive multicentre diagnostic accuracy study in the UK-the ATHENA study.

INTRODUCTION: The diagnosis of neovascular age-related macular degeneration (nAMD), the leading cause of visual impairment in the developed world, relies on the interpretation of various imaging tests of the retina. These include invasive angiographic methods, such as Fundus Fluorescein Angiography (FFA) and, on occasion, Indocyanine-Green Angiography (ICGA). Newer, non-invasive imaging modalities, predominately Optical Coherence Tomography (OCT) and Optical Coherence Tomography Angiography (OCTA), have drastically transformed the diagnostic approach to nAMD. The aim of this study is to undertake a comprehensive diagnostic accuracy assessment of the various imaging modalities used in clinical practice for the diagnosis of nAMD (OCT, OCTA, FFA and, when a variant of nAMD called Polypoidal Choroidal Vasculopathy is suspected, ICGA) both alone and in various combinations. METHODS AND ANALYSIS: This is a non-inferiority, prospective, randomised diagnostic accuracy study of 1067 participants. Participants are patients with clinical features consistent with nAMD who present to a National Health Service secondary care ophthalmology unit in the UK. Patients will undergo OCT as per standard practice and those with suspicious features of nAMD on OCT will be approached for participation in the study. Patients who agree to take part will also undergo both OCTA and FFA (and ICGA if indicated). Interpretation of the imaging tests will be undertaken by clinicians at recruitment sites. A randomised design was selected to avoid bias from consecutive review of all imaging tests by the same clinician. The primary outcome of the study will be the difference in sensitivity and specificity between OCT+OCTA and OCT+FFA (±ICGA) for nAMD detection as interpreted by clinicians at recruitment sites. ETHICS AND DISSEMINATION: The study has been approved by the South Central-Oxford B Research Ethics Committee with reference number 21/SC/0412.Dissemination of study results will involve peer-review publications, presentations at major national and international scientific conferences. TRIAL REGISTRATION NUMBER: ISRCTN18313457.

Radar for Europa Assessment and Sounding: Ocean to Near-Surface (REASON).

The Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) is a dual-frequency ice-penetrating radar (9 and 60 MHz) onboard the Europa Clipper mission. REASON is designed to probe Europa from exosphere to subsurface ocean, contributing the third dimension to observations of this enigmatic world. The hypotheses REASON will test are that (1) the ice shell of Europa hosts liquid water, (2) the ice shell overlies an ocean and is subject to tidal flexing, and (3) the exosphere, near-surface, ice shell, and ocean participate in material exchange essential to the habitability of this moon. REASON will investigate processes governing this material exchange by characterizing the distribution of putative non-ice material (e.g., brines, salts) in the subsurface, searching for an ice-ocean interface, characterizing the ice shell's global structure, and constraining the amplitude of Europa's radial tidal deformations. REASON will accomplish these science objectives using a combination of radar measurement techniques including altimetry, reflectometry, sounding, interferometry, plasma characterization, and ranging. Building on a rich heritage from Earth, the moon, and Mars, REASON will be the first ice-penetrating radar to explore the outer solar system. Because these radars are untested for the icy worlds in the outer solar system, a novel approach to measurement quality assessment was developed to represent uncertainties in key properties of Europa that affect REASON performance and ensure robustness across a range of plausible parameters suggested for the icy moon. REASON will shed light on a never-before-seen dimension of Europa and - in concert with other instruments on Europa Clipper - help to investigate whether Europa is a habitable world.

Histomorphologic changes of the long head of the biceps tendon in common shoulder pathologies.

PURPOSE: To assess molecular and histologic differences between the proximal (intra-articular) and distal (extra-articular) portions of the long head of the biceps (LHB) tendon in 3 different disease states (biceps instability, tendinosis, and degenerative joint disease [DJD]) compared with a healthy tendon (fresh frozen). METHODS: We used 32 LHB tendons of patients undergoing tenodesis (mean age, 54.7 ± 10.1 years) and 9 harvested tissue donors. Tendons were divided according to 4 diagnostic groups: (1) biceps instability, (2) tendinosis, (3) DJD, and (4) normal control. After sectioning, tendons were fixed in formalin and stained with H&E and alcian blue for histologic analysis. Measurements of collagen organization by use of polarized light microscopy was then performed, and protein expression for type I and type III collagen, tenascin C, and decorin was determined. RESULTS: There were no statistical differences found for protein expression of type I or type III collagen, tenascin C, or decorin. The proximal and distal regions of the tendons had statistically significant differences in alcian blue staining, with the proximal portion containing a higher amount of proteoglycan (instability, P = .001; tendinosis, P = .005; DJD, P = .008; control, P = .011). When compared with the nonpathologic control tendons, a significant increase in alcian blue staining for the proximal region was seen in all 3 groups. Total polarized light analysis showed that the distal tendon had a significantly higher intensity (organization) compared with the proximal tendon (P < .001); this was also seen in all of the diagnostic groups (instability, P = .010; tendinosis, P = .013; DJD, P = .07; control, P = .028). CONCLUSIONS: This study showed a greater degree of degeneration of the proximal (intra-articular) regions of the LHB tendon when compared with the distal regions in all pathologic groups. However, no major differences at the cellular level were found among groups. CLINICAL RELEVANCE: The pathomechanisms of the various forms of known LHB diagnoses are not yet fully understood and basic science studies may help in understanding their etiology and therefore optimizing treatment options.

LAparoscopic Versus Abdominal hysterectomy (LAVA): protocol of a randomised controlled trial.

INTRODUCTION: There is uncertainty about the advantages and disadvantages of laparoscopic hysterectomy compared with abdominal hysterectomy, particularly the relative rate of complications of the two procedures. While uptake of laparoscopic hysterectomy has been slow, the situation is changing with greater familiarity, better training, better equipment and increased proficiency in the technique. Thus, a large, robust, multicentre randomised controlled trial (RCT) is needed to compare contemporary laparoscopic hysterectomy with abdominal hysterectomy to determine the safest and most cost-effective technique. METHODS AND ANALYSIS: A parallel, open, non-inferiority, multicentre, randomised controlled, expertise-based surgery trial with integrated health economic evaluation and an internal pilot with an embedded qualitative process evaluation. A within trial-based economic evaluation will explore the cost-effectiveness of laparoscopic hysterectomy compared with open abdominal hysterectomy. We will aim to recruit 3250 women requiring a hysterectomy for a benign gynaecological condition and who were suitable for either laparoscopic or open techniques. The primary outcome is major complications up to six completed weeks postsurgery and the key secondary outcome is time from surgery to resumption of usual activities using the personalised Patient-Reported Outcomes Measurement Information System Physical Function questionnaire. The principal outcome for the economic evaluation is to be cost per QALY at 12 months' postsurgery. A secondary analysis is to be undertaken to generate costs per major surgical complication avoided and costs per return to normal activities. ETHICS AND DISSEMINATION: The study was approved by the West Midlands-Edgbaston Research Ethics Committee, 18 February 2021 (Ethics ref: 21/WM/0019). REC approval for the protocol version 2.0 dated 2 February 2021 was issued on 18 February 2021.We will present the findings in national and international conferences. We will also aim to publish the findings in high impact peer-reviewed journals. We will disseminate the completed paper to the Department of Health, the Scientific Advisory Committees of the RCOG, the Royal College of Nurses (RCN) and the BSGE. TRIAL REGISTRATION NUMBER: ISRCTN14566195.

Investigating Europa's Habitability with the Europa Clipper.

The habitability of Europa is a property within a system, which is driven by a multitude of physical and chemical processes and is defined by many interdependent parameters, so that its full characterization requires collaborative investigation. To explore Europa as an integrated system to yield a complete picture of its habitability, the Europa Clipper mission has three primary science objectives: (1) characterize the ice shell and ocean including their heterogeneity, properties, and the nature of surface-ice-ocean exchange; (2) characterize Europa's composition including any non-ice materials on the surface and in the atmosphere, and any carbon-containing compounds; and (3) characterize Europa's geology including surface features and localities of high science interest. The mission will also address several cross-cutting science topics including the search for any current or recent activity in the form of thermal anomalies and plumes, performing geodetic and radiation measurements, and assessing high-resolution, co-located observations at select sites to provide reconnaissance for a potential future landed mission. Synthesizing the mission's science measurements, as well as incorporating remote observations by Earth-based observatories, the James Webb Space Telescope, and other space-based resources, to constrain Europa's habitability, is a complex task and is guided by the mission's Habitability Assessment Board (HAB).

Exploring the Interior of Europa with the Europa Clipper.

The Galileo mission to Jupiter revealed that Europa is an ocean world. The Galileo magnetometer experiment in particular provided strong evidence for a salty subsurface ocean beneath the ice shell, likely in contact with the rocky core. Within the ice shell and ocean, a number of tectonic and geodynamic processes may operate today or have operated at some point in the past, including solid ice convection, diapirism, subsumption, and interstitial lake formation. The science objectives of the Europa Clipper mission include the characterization of Europa's interior; confirmation of the presence of a subsurface ocean; identification of constraints on the depth to this ocean, and on its salinity and thickness; and determination of processes of material exchange between the surface, ice shell, and ocean. Three broad categories of investigation are planned to interrogate different aspects of the subsurface structure and properties of the ice shell and ocean: magnetic induction, subsurface radar sounding, and tidal deformation. These investigations are supplemented by several auxiliary measurements. Alone, each of these investigations will reveal unique information. Together, the synergy between these investigations will expose the secrets of the Europan interior in unprecedented detail, an essential step in evaluating the habitability of this ocean world.

In vitro changes in human tenocyte cultures obtained from proximal biceps tendon: multiple passages result in changes in routine cell markers.

PURPOSE: Results of in vitro cell models are commonly used to promote new therapies (e.g., platelet-rich plasma), and clinicians have to be aware of the specific limitations of such models. To gain a sufficient and effective cell load, many current in vitro models use cells multiplied through various passages. This is especially important in tendon-like cell (TLC) models, since native tendon tissue is not available unlimited and contains limited amount of tenocytes. The purpose was to determine the occurrence of phenotypic changes following extended monolayer culture of TLCs, according to cell-passage number. METHODS: Tendon samples were obtained from 15 healthy patients undergoing biceps tenodesis. Tendons were digested and cultured (monolayer) for six passages. Tendon-specific markers (collagens I and III, decorin, tenascin-C, and tenomodulin) and their histology were analyzed using gene expression and protein content assays. Native cells, the cells cultured and cells passaged one to six times were analyzed at each passage. RESULTS: Gene expression of types I and III collagen of cultured TLCs significantly decreased after two passages. Gene expression of decorin, tenascin-C, and tenomodulin exhibited a trend of decreased gene expression with increased passage. Protein levels of types I and III collagen and decorin decreased after four passages. CONCLUSIONS: The significant findings let conclude that tenocyte-like cells obtained from human LHB can be maintained in monolayer culture at low passages, before the signs of phenotypic drift are present. But researchers must be aware of rapid phenotypic drift at higher passage numbers. Therefore, only cells within the first 3 passages should be used as a precaution for in vitro monolayer cell models, and one has to be aware of the phenotypic changes if TLCs passaged multiple times are used. The clinical relevance of this data is that understanding of in vitro TLC models, and their limitations may finally help the clinician to judge the potential of experimental data of new biologic treatment options.

Uterine artery embolization or myomectomy for women with uterine fibroids: Four-year follow-up of a randomised controlled trial.

OBJECTIVE: To examine the quality of life experienced by women with symptomatic uterine fibroids who had been treated with UAE in comparison to myomectomy. We report the four-year follow-up of the FEMME randomised trial. Two-year follow-up data has been previously reported. STUDY DESIGN: Premenopausal women who had symptomatic uterine fibroids amenable to myomectomy or uterine artery embolization were recruited from 29 UK hospitals. Women were excluded if they had significant adenomyosis, any malignancy, pelvic inflammatory disease or had had a previous open myomectomy or uterine artery embolization.Participants were randomised to myomectomy or embolization in a 1:1 ratio using a minimisation algorithm. Myomectomy could be open abdominal, laparoscopic or hysteroscopic, according to clinician preference. Embolization of the uterine arteries was performed according to local practice, under fluoroscopic guidance.The primary outcome measure was the Uterine Fibroid Symptom Quality of Life questionnaire, adjusted for baseline score and reported here at four years post-randomisation. Subsequent procedures for fibroids, pregnancy and outcome were amongst secondary outcomes.Trial registration ISRCTN70772394 https://doi.org/10.1186/ISRCTN70772394. RESULTS: 254 women were randomized, 127 to myomectomy (105 underwent myomectomy) and 127 to uterine artery embolization (98 underwent embolization). At four years, 67 (53%) and 81 (64%) completed UFS-QoL quality of life scores. Mean difference in the UFS-QoL at 4 years was 5.0 points (95% CI -1.4 to 11.5; p = 0.13) in favour of myomectomy. There were 15 pregnancies in the UAE group and 7 in the myomectomy group, with a cumulative pregnancy rate to four years of 15% and 6% respectively (hazard ratio: 0.48; 95% CI 0.18-1.28). The cumulative repeat procedure rate to four years was 24% in the UAE group and 13% in the myomectomy group (hazard ratio: 0.53; 95% CI 0.27-1.05). CONCLUSIONS: Myomectomy resulted in greater improvement in quality of life compared with uterine artery embolization, although by four years, this difference was not statistically significant. Missing data may limit the generalisability of this result. The numbers of women becoming pregnant were too small draw a conclusion on the effect of the procedures on fertility.

Uterine artery embolisation versus myomectomy for premenopausal women with uterine fibroids wishing to avoid hysterectomy: the FEMME RCT.

BACKGROUND: Uterine fibroids are the most common tumour in women of reproductive age and are associated with heavy menstrual bleeding, abdominal discomfort, subfertility and reduced quality of life. For women wishing to retain their uterus and who do not respond to medical treatment, myomectomy and uterine artery embolisation are therapeutic options. OBJECTIVES: We examined the clinical effectiveness and cost-effectiveness of uterine artery embolisation compared with myomectomy in the treatment of symptomatic fibroids. DESIGN: A multicentre, open, randomised trial with a parallel economic evaluation. SETTING: Twenty-nine UK hospitals. PARTICIPANTS: Premenopausal women who had symptomatic uterine fibroids amenable to myomectomy or uterine artery embolisation were recruited. Women were excluded if they had significant adenomyosis, any malignancy or pelvic inflammatory disease or if they had already had a previous open myomectomy or uterine artery embolisation. INTERVENTIONS: Participants were randomised to myomectomy or embolisation in a 1 : 1 ratio using a minimisation algorithm. Myomectomy could be open abdominal, laparoscopic or hysteroscopic. Embolisation of the uterine arteries was performed under fluoroscopic guidance. MAIN OUTCOME MEASURES: The primary outcome was the Uterine Fibroid Symptom Quality of Life questionnaire (with scores ranging from 0 to 100 and a higher score indicating better quality of life) at 2 years, adjusted for baseline score. The economic evaluation estimated quality-adjusted life-years (derived from EuroQol-5 Dimensions, three-level version, and costs from the NHS perspective). RESULTS: A total of 254 women were randomised - 127 to myomectomy (105 underwent myomectomy) and 127 to uterine artery embolisation (98 underwent embolisation). Information on the primary outcome at 2 years was available for 81% (n = 206) of women. Primary outcome scores at 2 years were 84.6 (standard deviation 21.5) in the myomectomy group and 80.0 (standard deviation 22.0) in the uterine artery embolisation group (intention-to-treat complete-case analysis mean adjusted difference 8.0, 95% confidence interval 1.8 to 14.1, p = 0.01; mean adjusted difference using multiple imputation for missing responses 6.5, 95% confidence interval 1.1 to 11.9). The mean difference in the primary outcome at the 4-year follow-up time point was 5.0 (95% CI -1.4 to 11.5; p = 0.13) in favour of myomectomy. Perioperative and postoperative complications from all initial procedures occurred in similar percentages of women in both groups (29% in the myomectomy group vs. 24% in the UAE group). Twelve women in the uterine embolisation group and six women in the myomectomy group reported pregnancies over 4 years, resulting in seven and five live births, respectively (hazard ratio 0.48, 95% confidence interval 0.18 to 1.28). Over a 2-year time horizon, uterine artery embolisation was associated with higher costs than myomectomy (mean cost £7958, 95% confidence interval £6304 to £9612, vs. mean cost £7314, 95% confidence interval £5854 to £8773), but with fewer quality-adjusted life-years gained (0.74, 95% confidence interval 0.70 to 0.78, vs. 0.83, 95% confidence interval 0.79 to 0.87). The differences in costs (difference £645, 95% confidence interval -£1381 to £2580) and quality-adjusted life-years (difference -0.09, 95% confidence interval -0.11 to -0.04) were small. Similar results were observed over the 4-year time horizon. At a threshold of willingness to pay for a gain of 1 QALY of £20,000, the probability of myomectomy being cost-effective is 98% at 2 years and 96% at 4 years. LIMITATIONS: There were a substantial number of women who were not recruited because of their preference for a particular treatment option. CONCLUSIONS: Among women with symptomatic uterine fibroids, myomectomy resulted in greater improvement in quality of life than did uterine artery embolisation. The differences in costs and quality-adjusted life-years are very small. Future research should involve women who are desiring pregnancy. TRIAL REGISTRATION: This trial is registered as ISRCTN70772394. FUNDING: This study was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme, and will be published in full in Health Technology Assessment; Vol. 26, No. 22. See the NIHR Journals Library website for further project information.

WHAT IS THE PROBLEM?: Uterine fibroids are the most common non-cancerous tumour in women of childbearing age. Uterine fibroids are associated with heavy bleeding, lower chances of having children and reduced quality of life. Traditional surgical options were either to remove the fibroids (via myomectomy) or to completely remove the womb. A newer approach, known as uterine artery embolisation, involves blocking the blood supply to the fibroids in the womb. WHAT DID WE PLAN TO DO?: We compared myomectomy with uterine artery embolisation in women with fibroids who wanted to keep their womb. We wanted to see which treatment improved quality of life, was associated with the fewest complications and was the best value for money for the NHS. We also wanted to see if either treatment had an impact on women's ability to get pregnant and give birth. We included 254 women in a clinical trial. Women were assigned to have myomectomy or uterine artery embolisation at random to ensure a fair comparison. Women completed questionnaires about their symptoms and quality of life at intervals up to 4 years after treatment. WHAT DID WE FIND?: We found that myomectomy improved women's quality of life more than uterine artery embolisation. Complications from the treatments occurred in a similar proportion of women. There appeared to be no difference on reproductive hormone levels between treatments. Too few women in the trial got pregnant for any difference in the numbers of women having children to be seen. The differences in costs and overall disease burden were small. WHAT DOES THIS MEAN?: Both treatments improve quality of life and cost about the same to the NHS but, on average, myomectomy will provide greater benefit to women. There is no evidence to suggest that either treatment is unsuitable for women wanting to get pregnant, but more research is needed in younger women.

Large-scale cryovolcanic resurfacing on Pluto.

The New Horizons spacecraft returned images and compositional data showing that terrains on Pluto span a variety of ages, ranging from relatively ancient, heavily cratered areas to very young surfaces with few-to-no impact craters. One of the regions with very few impact craters is dominated by enormous rises with hummocky flanks. Similar features do not exist anywhere else in the imaged solar system. Here we analyze the geomorphology and composition of the features and conclude this region was resurfaced by cryovolcanic processes, of a type and scale so far unique to Pluto. Creation of this terrain requires multiple eruption sites and a large volume of material (>104 km3) to form what we propose are multiple, several-km-high domes, some of which merge to form more complex planforms. The existence of these massive features suggests Pluto's interior structure and evolution allows for either enhanced retention of heat or more heat overall than was anticipated before New Horizons, which permitted mobilization of water-ice-rich materials late in Pluto's history.

Increased plasma chymase concentration and mast cell chymase expression in venous neointimal lesions of patients with CKD and ESRD.

The underlying inflammatory component of chronic kidney disease may predispose blood vessels to intimal hyperplasia (IH), which is the primary cause of dialysis access failure. We hypothesize that vascular pathology and markers of IH formation are antecedent to arteriovenous (AV) fistula creation. Blood, cephalic, and basilic vein segments were collected from predialysis chronic kidney disease (CKD) patients with no previous AV access and patients with end-stage renal disease (ESRD). Immunohistochemistry was performed with antibodies against mast cell chymase, transforming growth factor-beta (TGF-ß) and interleukin-6 (IL-6), which cause IH. Plasma chymase was measured by ELISA. IH was present in 91% of CKD and 75% of ESRD vein segments. Chymase was abundant in vessels with IH, with the greatest expression in intima and medial layers, and virtually absent in the controls. Chymase colocalized with TGF-ß1 and IL-6. Plasma chymase concentration was elevated up to 33-fold in patients with CKD versus controls and was associated with increased chymase in vessels with IH. We show that chymase expression in vessels with IH corresponds with plasma chymase concentrations. As chymase inhibition attenuates IH in animal models, and we find chymase is highly expressed in IH lesions of patients with CKD and ESRD, we speculate that chymase inhibition could have therapeutic value in humans.

Material properties and composition of soft-tissue fixation.

Surgical interference screws and suture anchors for attaching soft tissue, such as ligaments and tendons, to bone are routinely used in arthroscopic surgery and sports medicine. Interference screw fixation provides a press fit between bone, graft/tendon, and screw and is frequently used to attach replacement ligaments in tunnels drilled for anterior and posterior cruciate ligament reconstruction. Suture anchors are used in surgical procedures wherein it is necessary for a surgeon to attach (tie) tissue to the surface of the bone, for example, during joint reconstruction and ligament repair or replacement. The composition of these implants ranges from metals to polymers and composites. Typically, because of the relatively large amount of torque that must be applied during insertion, these screws are constructed from metal. However, interference screws and suture anchors have also been constructed from bioabsorbable polymers and composites. The ideal material would (1) provide adequate mechanical fixation, (2) completely degrade once no longer needed, and (3) be completely replaced by bone. Because no material has been shown to be superior for all applications, the surgeon must weigh the advantages and disadvantages of each to evaluate the optimum material for a given application and patient. The purpose of this article is to present a comprehensive review of the commercially available interference screws and suture anchors, with an emphasis on implant composition, interaction, and design. This article provides the orthopaedic surgeon with a background on biomaterials, specifically those used in interference screws and suture anchors. Because there is no material that is perfect for all surgical situations, this review can be used to make educated decisions on a case-by-case basis.

Ouabain, a circulating hormone secreted by the adrenals, is pivotal in cardiovascular disease. Fact or fantasy?

Substantial evidence points to the presence in human plasma of an inhibitor of the sodium/potassium pump which plays a central role in the pathophysiology of circulatory disorders, including essential hypertension. Studies from the 1980/90s claimed that this inhibitor was identical or very similar in structure to plant-derived ouabain and was synthesized by the adrenal cortex. However, the physical evidence in studies reporting isolation and identification of ouabain in human plasma appears insecure on closer examination. Additionally, reported circulating levels of immunoreactive ouabain in humans vary greatly, the ability of the human adrenal glands to secrete ouabain is questionable and the original commercial assay for measuring immunoreactive ouabain is no longer available. We submit that the position of ouabain as an endogenous, adrenally produced regulator of the sodium pump is of such importance that the current evidence needs either to put on a more secure footing or to lose its current status.

Dunes on Pluto.

The surface of Pluto is more geologically diverse and dynamic than had been expected, but the role of its tenuous atmosphere in shaping the landscape remains unclear. We describe observations from the New Horizons spacecraft of regularly spaced, linear ridges whose morphology, distribution, and orientation are consistent with being transverse dunes. These are located close to mountainous regions and are orthogonal to nearby wind streaks. We demonstrate that the wavelength of the dunes (~0.4 to 1 kilometer) is best explained by the deposition of sand-sized (~200 to ~300 micrometer) particles of methane ice in moderate winds (<10 meters per second). The undisturbed morphology of the dunes, and relationships with the underlying convective glacial ice, imply that the dunes have formed in the very recent geological past.

Charon tectonics.

New Horizons images of Pluto's companion Charon show a variety of terrains that display extensional tectonic features, with relief surprising for this relatively small world. These features suggest a global extensional areal strain of order 1% early in Charon's history. Such extension is consistent with the presence of an ancient global ocean, now frozen.

A rapid LC-MS method for determination of plasma anion profiles of acidotic patients.

In metabolic acidosis, the concentrations of anions associated with intermediary metabolism are increased and can make a significant contribution to the observed acidosis. Here we describe a method for the rapid determination of the plasma ultrafiltrate profile of these anions using liquid chromatography coupled to electrospray ionisation mass spectrometry (LC/ESI-MS). The ultrafiltrate from patients with acidosis resulting from various causes were examined and the results compared to control values. Using the LC/ESI-MS method described, a unique plasma ultrafiltrate anion profile was obtained for each of the groups studied that provides rapid diagnosis of the type of underlying acidosis.