55 research outputs found

    Serum Fetuin-A Levels Are Associated with Serum Triglycerides Before and 6 Months after Bariatric Surgery

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    OBJECTIVE: The elucidation of the changes of fetuin-A in the context of bariatric surgery. DESIGN: Twenty obese patients (8 males, 12 females; body mass index = 42.5±3.4 kg/m2) were studied at baseline and 6 months after bariatric surgery. RESULTS: Serum fetuin-A levels did not differ with regard to the presence of each individual component of the Metabolic Syndrome (MetS) at baseline, except for hypertriglyceridaemia [increased serum fetuin-A levels (p=0.011)]. Circulating fetuin-A was positively correlated with serum triglycerides (TG) (r=0.461, p=0.047) and negatively correlated with serum globulins (r=-0.477, p=0.033) and C-reactive protein (CRP) (r=-0.604, p=0.010), while it independently predicted TG at baseline. Circulating fetuin-A did not change during the 6 months either in the whole population or in the subgroups of patients who were positive for each individual component of MetS at baseline and negative for this component at 6 months of follow-up, except for hypertriglyceridaemia [reduction of serum fetuin-A levels (p=0.046)]. The subgroup of patients with a decrease in circulating fetuin-A during the 6 months was characterized by a smaller reduction of serum globulins (p=0.003) and CRP (p=0.049). The change in serum fetuin-A levels over the 6 months was positively correlated with the change in TG (r=0.592, p=0.006) and negatively correlated with the change in serum globulins (r=-0.523, p=0.018) and CRP (r=-.494, p=0.037). CONCLUSIONS: Circulating fetuin-A predicted serum triglycerides before as well as 6 months after bariatric surgery.info:eu-repo/semantics/publishedVersio

    No advantage for remembering horizontal over vertical spatial locations learned from a single viewpoint

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    Previous behavioral and neurophysiological research has shown better memory for horizontal than for vertical locations. In these studies, participants navigated toward these locations. In the present study we investigated whether the orientation of the spatial plane per se was responsible for this difference. We thus had participants learn locations visually from a single perspective and retrieve them from multiple viewpoints. In three experiments, participants studied colored tags on a horizontally or vertically oriented board within a virtual room and recalled these locations with different layout orientations (Exp. 1) or from different room-based perspectives (Exps. 2 and 3). All experiments revealed evidence for equal recall performance in horizontal and vertical memory. In addition, the patterns for recall from different test orientations were rather similar. Consequently, our results suggest that memory is qualitatively similar for both vertical and horizontal two-dimensional locations, given that these locations are learned from a single viewpoint. Thus, prior differences in spatial memory may have originated from the structure of the space or the fact that participants navigated through it. Additionally, the strong performance advantages for perspective shifts (Exps. 2 and 3) relative to layout rotations (Exp. 1) suggest that configurational judgments are not only based on memory of the relations between target objects, but also encompass the relations between target objects and the surrounding room—for example, in the form of a memorized view

    Virtual environments as memory training devices in navigational tasks for older adults.

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    Cognitive training approaches using virtual environments (VEs) might counter age-related visuospatial memory decline and associated difficulties in wayfinding. However, the effects of the visual design of a VE in route learning are not fully understood. Therefore, we created a custom-designed VE optimized for route learning, with adjusted levels of realism and highlighted landmark locations (MixedVE). Herein we tested participants' route recall performance in identifying direction of turn at the intersection with this MixedVE against two baseline alternatives (AbstractVE, RealisticVE). An older vs. a younger group solved the tasks in two stages (immediate vs. delayed recall by one week). Our results demonstrate that the MixedVE facilitates better recall accuracy than the other two VEs for both age groups. Importantly, this pattern persists a week later. Additionally, our older participants were mostly overconfident in their route recall performance, but the MixedVE moderated this potentially detrimental overconfidence. Before the experiment, participants clearly preferred the RealisticVE, whereas after the experiment, most of the younger, and many of the older participants, preferred the MixedVE. Taken together, our findings provide insights into the importance of tailoring visualization design in route learning with VEs. Furthermore, we demonstrate the great potential of the MixedVE and by extension, of similar VEs as memory training devices for route learning, especially for older participants

    Frequency and amplitude modulation of ultra-compact terahertz quantum cascade lasers using an integrated avalanche diode oscillator

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    Mode-locked comb sources operating at optical frequencies underpin applications ranging from spectroscopy and ultrafast physics, through to absolute frequency measurements and atomic clocks. Extending their operation into the terahertz frequency range would greatly benefit from the availability of compact semiconductor-based sources. However, the development of any compact mode-locked THz laser, which itself is inherently a frequency comb, has yet to be achieved without the use of an external stimulus. High-power, electrically pumped quantum cascade lasers (QCLs) have recently emerged as a promising solution, owing to their octave spanning bandwidths, the ability to achieve group-velocity dispersion compensation and the possibility of obtaining active mode-locking. Here, we propose an unprecedented compact architecture to induce both frequency and amplitude self-modulation in a THz QCL. By engineering a microwave avalanche oscillator into the laser cavity, which provides a 10 GHz self-modulation of the bias current and output power, we demonstrate multimode laser emission centered around 3 THz, with distinct multiple sidebands. The resulting microwave amplitude and frequency self-modulation of THz QCLs opens up intriguing perspectives, for engineering integrated self-mode-locked THz lasers, with impact in fields such as nano- and ultrafast photonics and optical metrology

    Heme oxygenase-1 and carbon monoxide in pulmonary medicine

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    Heme oxygenase-1 (HO-1), an inducible stress protein, confers cytoprotection against oxidative stress in vitro and in vivo. In addition to its physiological role in heme degradation, HO-1 may influence a number of cellular processes, including growth, inflammation, and apoptosis. By virtue of anti-inflammatory effects, HO-1 limits tissue damage in response to proinflammatory stimuli and prevents allograft rejection after transplantation. The transcriptional upregulation of HO-1 responds to many agents, such as hypoxia, bacterial lipopolysaccharide, and reactive oxygen/nitrogen species. HO-1 and its constitutively expressed isozyme, heme oxygenase-2, catalyze the rate-limiting step in the conversion of heme to its metabolites, bilirubin IXα, ferrous iron, and carbon monoxide (CO). The mechanisms by which HO-1 provides protection most likely involve its enzymatic reaction products. Remarkably, administration of CO at low concentrations can substitute for HO-1 with respect to anti-inflammatory and anti-apoptotic effects, suggesting a role for CO as a key mediator of HO-1 function. Chronic, low-level, exogenous exposure to CO from cigarette smoking contributes to the importance of CO in pulmonary medicine. The implications of the HO-1/CO system in pulmonary diseases will be discussed in this review, with an emphasis on inflammatory states

    Minimally invasive surgery and cancer: controversies part 1

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    Perhaps there is no more important issue in the care of surgical patients than the appropriate use of minimally invasive surgery (MIS) for patients with cancer. Important advances in surgical technique have an impact on early perioperative morbidity, length of hospital stay, pain management, and quality of life issues, as clearly proved with MIS. However, for oncology patients, historically, the most important clinical questions have been answered in the context of prospective randomized trials. Important considerations for MIS and cancer have been addressed, such as what are the important immunologic consequences of MIS versus open surgery and what is the role of laparoscopy in the staging of gastrointestinal cancers? This review article discusses many of the key controversies in the minimally invasive treatment of cancer using the pro–con debate format

    The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

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    AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease
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