SOMEWHERE by Paloma Vidal

Translated from the Portuguese by Jordan B. Jones

Failure of microvenous valves in small superficial veins is a key to the skin changes of venous insufficiency

ObjectiveTo determine the role of microvenous valves in the superficial venous system in the prevention of reflux and skin changes in the progression of venous insufficency.MethodsThe venous anatomy of 15 amputated lower limbs, eight free from clinical venous disease and seven with varicose veins and ulcers, was examined using retrograde venography corrosion casting. Prior to amputation, all limbs were scanned by duplex ultrasound to confirm the presence or absence of reflux in the great (GSV) and small saphenous veins or their tributaries. The resulting resin casts were photographed and mapped to show the position, orientation, and competency of valves in the superficial venous network. Casts were also examined by scanning electron microscopy.ResultsRetrograde venous filling was demonstrated in the “normal” limbs despite a competent GSV. Microvalves were identified down to the sixth generation of tributaries from the GSV. Only in regions where incompetence existed in microvalves out to the third (ie, the “boundary”) generation was the resin able to penetrate deeper into microvenous networks of the dermis. This was despite the presence of subsequent competent valves, which were able to be bypassed in the network. In limbs with varicose veins and venous ulcers, reflux into the small venous networks and capillary loops was more extensive with more dense networks and greater tortuousity.ConclusionsThis study demonstrates that valvular incompetence can occur independently in small superficial veins in the absence of reflux within the GSV and the major tributaries. We have shown that once there is incompetence of the third generation “boundary” microvalves, reflux can extend into the microvenous networks in the skin. These effects are markedly worse in the presence of GSV incompetence. We propose that degenerative changes with valve incompetence are required in both the larger proximal vessels and the small superficial veins, in particular at the “boundary” valve level, for the severe skin changes in venous insufficiency to occur.Clinical RelevanceThis study describes the presence of microvalves in the very small veins in the skin, which may be critical to whether skin changes occur in venous insufficiency. The concept may explain why some people with longstanding varicose veins do not develop venous ulcers. In addition, this article describes degenerative changes in the network of very small veins in the skin of the leg which may relate to appearances of reticular veins, corona phlebectatica, and venous flares. These degenerative changes occur without varicose veins but are much worse when they occur together

Hypotension during propofol sedation for colonoscopy:an exploratory analysis

BACKGROUND: Intraoperative and postoperative hypotension occur commonly and are associated with organ injury and poor outcomes. Changes in arterial blood pressure (BP) during procedural sedation are not well described. METHODS: Individual patient data from five trials of propofol sedation for colonoscopy and a clinical database were pooled and explored with logistic and linear regression. A literature search and focused meta-analysis compared the incidence of hypotension with propofol and alternative forms of procedural sedation. Hypotensive episodes were characterised by the original authors' definitions (typically systolic BP 5 min, and in 89 (23%) the episodes exceeded 10 min. Meta-analysis of 18 RCTs identified an increased risk ratio for the development of hypotension in procedures where propofol was used compared with the use of etomidate (two studies; n=260; risk ratio [RR] 2.0 [95% confidence interval: 1.37–2.92]; P=0.0003), remimazolam (one study; n=384; RR 2.15 [1.61–2.87]; P=0.0001), midazolam (14 studies; n=2218; RR 1.46 [1.18–1.79]; P=0.0004), or all benzodiazepines (15 studies; n=2602; 1.67 [1.41–1.98]; P<0.00001). Hypotension was less likely with propofol than with dexmedetomidine (one study; n=60; RR 0.24 [0.09–0.62]; P=0.003). CONCLUSIONS: Hypotension is common during propofol sedation for colonoscopy and of a magnitude and duration associated with harm in surgical patients

Diffusion Monte Carlo calculations for the ground states of atoms and ions in neutron star magnetic fields

The diffusion quantum Monte Carlo method is extended to solve the old theoretical physics problem of many-electron atoms and ions in intense magnetic fields. The feature of our approach is the use of adiabatic approximation wave functions augmented by a Jastrow factor as guiding functions to initialize the quantum Monte Carlo prodecure. We calcula te the ground state energies of atoms and ions with nuclear charges from Z= 2, 3, 4, ..., 26 for magnetic field strengths relevant for neutron stars.Comment: 6 pages, 1 figure, proceedings of the "9th International Conference on Path Integrals - New Trends and Perspectives", Max-Planck-Institut fur Physik komplexer Systeme, Dresden, Germany, September 23 - 28, 2007, to be published as a book by World Scientific, Singapore (2008

Association between incarceration and incident cardiovascular disease events: results from the CARDIA cohort study

BACKGROUND: Incarceration has been associated with higher cardiovascular risk, yet data evaluating its association with cardiovascular disease events are limited. The study objective was to evaluate the association between incarceration and incident fatal and non-fatal cardiovascular disease (CVD) events. METHODS: Black and white adults from the community-based Coronary Artery Risk Development in Young Adult (CARDIA) study (baseline 1985-86, n = 5105) were followed through August 2017. Self-reported incarceration was measured at baseline (1985-1986) and Year 2 (1987-1988), and fatal and non-fatal cardiovascular disease events, including coronary heart disease, stroke, and heart failure, and all-cause mortality, were captured through 2017. Analyses were completed in September 2019. Cumulative CVD incidence rates and Cox proportional hazards were compared overall by incarceration status. An interaction between incarceration and race was identified, so results were also analyzed by sex-race groups. RESULTS: 351 (6.9%) CARDIA participants reported a history of incarceration. Over 29.0 years mean follow-up, CVD incidence rate was 3.52 per 1000 person-years in participants with a history of incarceration versus 2.12 per 1000 person-years in participants without a history of incarceration (adjusted HR = 1.33 [95% CI, 0.90-1.95]). Among white men, incarceration was associated with higher risk of incident cardiovascular disease (adjusted HR = 3.35 [95% CI, 1.54-7.29) and all-cause mortality (adjusted HR = 2.52 [95% CI, 1.32-4.83]), but these associations were not statistically significant among other sex-race groups after adjustment. CONCLUSIONS: Incarceration was associated with incident cardiovascular disease rates, but associations were only significant in one sex-race group after multivariable adjustment

Musculoskeletal foot problems in primary care: what influences older people to consult?

Objective. To estimate the incidence of, and factors associated with, consultation for musculoskeletal foot problems in primary care

MicroRNA and metabolomics signatures for adrenomyeloneuropathy disease severity

Adrenomyeloneuropathy (AMN), the slow progressive phenotype of adrenoleukodystrophy (ALD), has no clinical plasma biomarker for disease progression. This feasibility study aimed to determine whether metabolomics and micro-RNA in blood plasma provide a potential source of biomarkers for AMN disease severity. Metabolomics and RNA-seq were performed on AMN and healthy human blood plasma. Biomarker discovery and pathway analyses were performed using clustering, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and regression against patient\u27s clinical Expanded Disability Status Score (EDSS). Fourteen AMN and six healthy control samples were analyzed. AMN showed strong disease-severity-specific metabolic and miRNA clustering signatures. Strong, significant clinical correlations were shown for 7-alpha-hydroxy-3-oxo-4-cholestenoate (7-HOCA) (r (2) = 0.83, p \u3c 0.00001), dehydroepiandrosterone sulfate (DHEA-S; r (2) = 0.82, p \u3c 0.00001), hypoxanthine (r (2) = 0.82, p \u3c 0.00001), as well as miRNA-432-5p (r (2) = 0.68, p \u3c 0.00001). KEGG pathway comparison of mild versus severe disease identified affected downstream systems: GAREM, IGF-1, CALCRL, SMAD2&3, glutathione peroxidase, LDH, and NOS. This feasibility study demonstrates that miRNA and metabolomics are a source of potential plasma biomarkers for disease severity in AMN, providing both a disease signature and individual markers with strong clinical correlations. Network analyses of affected systems implicate differentially altered vascular, inflammatory, and oxidative stress pathways, suggesting disease-severity-specific mechanisms as a function of disease severity

Magnetron priming by multiple cathodes

A relativistic magnetron priming technique using multiple cathodes is simulated with a three-dimensional, fully electromagnetic, particle-in-cell code. This technique is based on electron emission from N/2N∕2 individual cathodes in an NN-cavity magnetron to prime the ππ mode. In the case of the six-cavity relativistic magnetron, ππ-mode start-oscillation times are reduced up to a factor of 4, and mode competition is suppressed. Most significantly, the highest microwave field power is observed by utilizing three cathodes compared to other recently explored priming techniques.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87840/2/081501_1.pd

PHOENIX model chromospheres of mid- to late-type M dwarfs

We present semi-empirical model chromospheres computed with the atmosphere code PHOENIX. The models are designed to fit the observed spectra of five mid- to late-type M dwarfs. Next to hydrogen lines from the Balmer series we used various metal lines, e. g. from Fe {\sc i}, for the comparison between data and models. Our computations show that an NLTE treatment of C, N, O impacts on the hydrogen line formation, while NLTE treatment of less abundant metals such as nickel influences the lines of the considered species itself. For our coolest models we investigated also the influence of dust on the chromospheres and found that dust increases the emission line flux. Moreover we present an (electronically published) emission line list for the spectral range of 3100 to 3900 and 4700 to 6800 \AA for a set of 21 M dwarfs and brown dwarfs. The line list includes the detection of the Na {\sc i} D lines in emission for a L3 dwarf.Comment: 14 pages, 18 figure