468 research outputs found

    The Biological Standard of Living in the two Germanies.

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    Physical stature is used as a proxy for the biological standard of living in the two Germanies before and after unification in an analysis of a cross-sectional sample (1998) of adult heights, as well as among military recruits of the 1990s. West Germans tended to be taller than East Germans throughout the period under consideration. Contrary to official proclamations of a classless society, there were substantial social differences in physical stature in East-Germany. Social differences in height were greater in the East among females, and less among males than in the West. The difficulties experienced by the East-German population after 1961 is evident in the increase in social inequality of physical stature thereafter, as well as in the increasing gap relative to the height of the West-German population. After unification, however, there is a tendency for East-German males, but not of females, to catch up with their West-German counterparts

    Convex optimization problem prototyping for image reconstruction in computed tomography with the Chambolle-Pock algorithm

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    The primal-dual optimization algorithm developed in Chambolle and Pock (CP), 2011 is applied to various convex optimization problems of interest in computed tomography (CT) image reconstruction. This algorithm allows for rapid prototyping of optimization problems for the purpose of designing iterative image reconstruction algorithms for CT. The primal-dual algorithm is briefly summarized in the article, and its potential for prototyping is demonstrated by explicitly deriving CP algorithm instances for many optimization problems relevant to CT. An example application modeling breast CT with low-intensity X-ray illumination is presented.Comment: Resubmitted to Physics in Medicine and Biology. Text has been modified according to referee comments, and typos in the equations have been correcte

    A comparative analysis using flowmeter, laser-Doppler spectrophotometry, and indocyanine green-videoangiography for detection of vascular tenosis in free flaps

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    The effects of gradual vascular occlusion on the blood supply of perfused areas are poorly described. Information relating to the comparison of flap monitoring techniques is lacking. Varying stenotic conditions (0%, 25%, 50%, 75% and 100%) were generated on purpose at the A. and V. femoralis in the rat model. Analyses included flowmeter, simultaneous laser-Doppler flowmetry and tissue spectrophotometry (O2C) and indocyanine green- (ICG-) videoangiography with integrated FLOW 800 tool. A Random Forests prediction model was used to analyse the importance of each method to diagnose the stenotic conditions. The ability to discriminate and to accurately estimate the probability of stenosis was assessed by Receiver Operating Characteristic (ROC) curves and calibration plots. Blood flow changes for all modalities were described in detail. Flowmeter displayed earliest a linear decrease as a result of increasing stenosis. A stenosis of 50% degrees was most difficult to detect correctly. The combination of flowmeter and ICG-videoangiography showed high diagnostic power for each stenotic situation (area under the ROC > 0.79). Flowmeter and ICG-videoangiography showed to be most relevant in detection of varying stenotic conditions and may change the clinical outcome. The O2C showed less effect on varying stenotic situations as the only surface monitoring device

    The mere-measurement effect of patient-reported outcomes:a systematic review and meta-analysis

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    Purpose: The mere-measurement effect is the phenomenon in which subjects exposed to measurements have their perceptions and/or behaviors on the inquired topic affected simply through the act of responding. Patient-reported outcomes (PROs) are increasingly used to assess patient perspective and quality of life in clinical trials and different health care settings. This systematic literature review aims to assess what is currently known about the mere-measurement effect of PROs. Methods: A systematic literature review and meta-analysis was conducted. We included studies that provided evidence on perceptual or behavioral changes in patients as a result of exposure to questionnaire items assessing PROs. All adult participants were included regardless of demographics. Any study design was considered eligible for inclusion. The databases MEDLINE [PubMed], CINAHL [Ebsco], Web of Science and ScienceDirect were searched. Results: The search resulted in 636 articles which led to a final extraction of nine. Overall, seven of the nine articles reported a significant main effect, i.e. presence of the mere-measurement effect. For the meta-analysis, thirteen different interventions were included. There was a one-directional, positive and significant overall risk ratio of 1.17 [CI95% 1.04;1.30]. Conclusion: This systematic review found significant potential for the mere-measurement effect to shape respondents’ behaviors or perceptions for the better, opening the door to the possibility of engineering PROs to serve as a subtle intervention. Future considerations and directions for research are discussed.</p

    Impact of different antithrombotics on the microcirculation and viability of perforator-based ischaemic skin flaps in a small animal model

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    The effects of antithrombotic drugs on random and free flap survival have been investigated in the past, but the experimental and clinical results are not in agreement. A perforator-based critical ischaemia model was used to evaluate the effects of different perioperatively administered pharmaceutical agents on tissue ischaemia and to assess the potential additional haemorheological or vasodilative effects of antithrombotics on flap microcirculation. Combined laser Doppler flowmetry and remission spectroscopy revealed an increase in certain microcirculation parameters in most groups in comparison with saline controls, and these changes correlated with flap survival. Clopidogrel and hirudin significantly improved the amount of viable flap tissue in comparison with controls, while unfractioned heparin had a negative effect on flap survival. Low molecular weight heparin, aspirin, pentoxifylline, and hydroxyethyl starch had no impact on the amount of viable flap tissue. A higher complication rate was observed in all experimental groups, but only clopidogrel had a negative impact on the flap viability. Our results add to the body of evidence supporting the conclusion that perioperative antithrombotic treatment improves flap survival. Clopidogrel and hirudin are effective pharmacological agents that significantly increased the viability of perforator-based skin flaps in rats, but at a higher risk of postoperative bleeding

    Impact of different antithrombotics on the microcirculation and viability of perforator-based ischaemic skin flaps in a small animal model

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    The effects of antithrombotic drugs on random and free flap survival have been investigated in the past, but the experimental and clinical results are not in agreement. A perforator-based critical ischaemia model was used to evaluate the effects of different perioperatively administered pharmaceutical agents on tissue ischaemia and to assess the potential additional haemorheological or vasodilative effects of antithrombotics on flap microcirculation. Combined laser Doppler flowmetry and remission spectroscopy revealed an increase in certain microcirculation parameters in most groups in comparison with saline controls, and these changes correlated with flap survival. Clopidogrel and hirudin significantly improved the amount of viable flap tissue in comparison with controls, while unfractioned heparin had a negative effect on flap survival. Low molecular weight heparin, aspirin, pentoxifylline, and hydroxyethyl starch had no impact on the amount of viable flap tissue. A higher complication rate was observed in all experimental groups, but only clopidogrel had a negative impact on the flap viability. Our results add to the body of evidence supporting the conclusion that perioperative antithrombotic treatment improves flap survival. Clopidogrel and hirudin are effective pharmacological agents that significantly increased the viability of perforator-based skin flaps in rats, but at a higher risk of postoperative bleeding

    Publisher Correction: A comparative analysis using flowmeter, laser-Doppler spectrophotometry, and indocyanine green-videoangiography for detection of vascular stenosis in free flaps

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    The original version of this Article contained an error in the title of the paper, where the word “spectrophotometry” was incorrectly given as “|spectrophotometry”. This has now been corrected in the PDF and HTML versions of the Article

    Prediction of Flap Necrosis by Using Indocyanine Green Videoangiography in Cases of Venous Occlusion in the Epigastric Flap Model of the Rat

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    Background A compromised free flap perfusion attributable to vascular occlusion requires immediate operative correction. Indocyanine green (ICG) videoangiography may reduce the risk of partial skin flap necrosis in high-risk free flaps in patients undergoing head and neck reconstruction. The purpose of this study was to determine the role of ICG in cases of venous congestion in a rat model. Methods A standardized epigastric flap was raised and repositioned in 35 rats. Full venous occlusion of the draining superficial inferior epigastric vein was temporarily applied for 4, 5, 6, or 7 hours. Blood flow measurements including simultaneous laser-Doppler flowmetry and tissue spectrophotometry (oxygen-to-see [O2C]) and ICG videoangiography with the FLOW 800 tool were performed before flap raising, after temporary venous stasis, and after clinical monitoring for 1 week. The Youden index computed from the receiver operating characteristic curve was used to define an optimal cutoff value for necrosis prediction after 4 and 6 hours of stasis. Results The ICG videoangiography with the FLOW 800 tool was found to be superior to O2C in the prediction of flap necrosis. The accuracy of prediction was moderate after an interval of 4 hours of stasis (area under the curve [AUC] = 0.661; 95% confidence interval [CI]: 0.489–0.834) and good after 6 hours of stasis (AUC = 0.787; 95% CI: 0.65–0.915). Conclusions The O2C does not reliably predict tissue necrosis in cases of venous congestion. ICG videoangiography is a valuable tool that can predict clinical outcome and provide guidance on whether to salvage a congested flap

    Detection of thrombosis in microvessels with indocyanine green videoangiography

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    Atherosclerosis is a systemic condition that is responsible for many diseases, and becomes a problem in cases where plaques form at several sites. The formation of a thrombotic embolus may jeopardise vascular operations, including microvascular anastomoses in replantation procedures or free tissue transfers. A mobile imaging tool for the detection of thrombosis preoperatively or intraoperatively would be valuable. An intimal injury, simulating removal of atherosclerotic plaques, was made microsurgically in 60 rat aortas, and results were analysed macroscopically, histologically, and with intraoperative indocyanine green (ICG) videoangiography immediately postoperatively. The Spearman and Pearson correlation tests were used to compare the three techniques. The sensitivity and specificity of ICG videoangiography was calculated in relation to both macroscopic and histological results. Detection of thrombosis was possible in 25 cases, and in 18 cases no thrombosis was correctly diagnosed by all methods used. In 31 of 60 specimens formation of thrombus was detected histologically, and in 29 of 60 examinations it was detected clinically, which yielded a correlation of 93.5% between the two examinations. Macroscopic analysis correlated better with ICG videoangiography (sensitivity 86.2% and specificity 64.5%) than histological observations (sensitivity 80.6% and specificity 62.1%). There was a significant correlation among all comparisons (each p ≤ 0.001) with correlation indexes of 0.94, 0.52, and 0.44 for macroscopic/histological, clinical/ICG videoangiographic, and ICG videoangiographic/histological results, respectively. Our results show that ICG videoangiography is an important method for the detection of formation of acute thrombi and may be an important tool in vascular procedures

    Synovial hemangioma of the knee joint in a 12-year-old boy: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Synovial hemangioma is a rare condition and is frequently misdiagnosed, leading to a diagnostic delay of many years.</p> <p>Case presentation</p> <p>We present a case of an atypical synovial hemangioma in a 12-year-old Caucasian boy with a diagnostic delay of 3 years.</p> <p>Conclusion</p> <p>It is important to know that synovial hemangioma mostly affects the knee joint, showing recurrent bloody effusions without a history of trauma. If there are no intermittent effusions, the diagnosis will be even more difficult. In cases of nonspecific symptoms and longstanding knee pain the diagnosis of a synovial hemangioma should also be considered in order to avoid diagnostic delay. Magnetic resonance imaging is the main diagnostic tool to evaluate patients with synovial hemangioma, showing characteristic lace-like or linear patterns.</p> <p>Angiography can identify feeder vessels and offers the possibility of embolisation in the same setting. Surgical excision, either done per arthroscopy or per arthrotomy, is recommended as soon as possible to avoid the risk of damage to the cartilage.</p
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