475 research outputs found
The feasibility and applications of non-invasive cardiac monitoring in obese patients undergoing day-case surgery: Results of a prospective observational study
Aims: This prospective observational study evaluates the utility of non-invasive cardiac monitoring in obese patients in the day-surgery case, considering factors, such as Body Mass Index (BMI) and anaesthesia technique. Background: Obese patients are more likely to be admitted to hospital or to get hospitalized because they are more prone to concomitant diseases and obesity itself is not a contraindication to day surgery. Obese patients are a high-risk patient population that may particularly benefit from monitoring perioperative haemodynamic variations. Methods: In this observational study, we compared haemodynamic variations between overweight or obese and normal weight patients undergoing day-case surgery. We adopted NICOM® as a non-invasive cardiac output monitoring. Objective: The aim of the current study was to investigate the haemodynamic impact of BMI and anaesthesia technique during day-case surgery procedures. The other goal was to evaluate the feasibility and applications of non-invasive cardiac output monitoring among the obese population in day-surgery. Results: 74 patients were included in the study. 34 were overweight or obese (weight 84 ± 10 kg, height 160 ± 10 cm, BMI ≈ 30 kg/m2), 40 were normal weight (weight 63 ± 15 kg, height 160 ± 10 cm, BMI ≈ 22 kg/m2). Compared to normal-weight patients, obese patients show an increase in blood pressure with a return to baseline values at the end of surgery (p < 0.05). The Cardiac Output (CO) shows a similar trend, whereas the heart rate is normal. A decrease in the Cardiac Index (CI) during the operation was noticed in both groups, the one in obese patients (p = 0.24) being greater. In the same way, the Stroke Volume Index (SVI) was lower in obese patients during surgery (p < 0.05). In spinal anaesthesia, the Total Peripheral Resistance Index (TPRI) was not statistically different between the groups of study. As for the TPRI in obese patients, we reported values similar to the ones in non-obese patients in spinal anaesthesia. In local anesthesia, TPRI was higher in obese patients than in non-obese. Conclusion: Cardiovascular alterations in relation to obesity include an increase in blood pressure, CO and SV. An inadequate monitoring of haemodynamic parameters is a risk factor for perioperative complications. NICOM® provides a continuous, non-invasive haemodynamic measurement
Pancreaticoduodenectomy model demonstrates a fundamental role of dysfunctional β cells in predicting diabetes
BACKGROUND. The appearance of hyperglycemia is due to insulin resistance, functional deficits in the secretion of insulin, and a reduction of β cell mass. There is a long-standing debate as to the relative contribution of these factors to clinically manifesting β cell dysfunction. The aim of this study was to verify the acute effect of one of these factors, the reduction of β cell mass, on the subsequent development of hyperglycemia. METHODS. To pursue this aim, nondiabetic patients, scheduled for identical pancreaticoduodenectomy surgery, underwent oral glucose tolerance tests (OGTT) and hyperglycemic clamp (HC) procedures, followed by arginine stimulation before and after surgery. Based on postsurgery OGTT, subjects were divided into 3 groups depending on glucose tolerance: normal glucose tolerance (post-NGT), impaired glucose tolerance (post-IGT), or having diabetes mellitus (post-DM). RESULTS. At baseline, the 3 groups showed similar fasting glucose and insulin levels; however, examining the various parameters, we found that reduced first-phase insulin secretion, reduced glucose sensitivity, and rate sensitivity were predictors of eventual postsurgery development of IGT and diabetes. CONCLUSION. Despite comparable functional mass and fasting glucose and insulin levels at baseline and the very same 50% mass reduction, only reduced first-phase insulin secretion and glucose sensitivity predicted the appearance of hyperglycemia. These functional alterations could be pivotal to the pathogenesis of type 2 diabetes (T2DM)
2022 report from the Auger-TA working group on UHECR arrival directions
After over 60 years, the powerful engines that accelerate ultra-high-energy
cosmic rays (UHECRs) to the formidable energies at which we observe them from
Earth remain mysterious. Assuming standard physics, we expect UHECR sources to
lie within the local Universe (up to a few hundred~Mpc). The distribution of
matter in the local Universe is anisotropic, and we expect this anisotropy to
be imprinted on the distribution of UHECR arrival directions. Even though
intervening intergalactic and Galactic magnetic fields deflect charged UHECRs
and can distort these anisotropies, some amount of information on the
distribution of the sources is preserved. In this proceedings contribution, we
present the results of the joint Pierre Auger Observatory and Telescope Array
searches for (a) the largest-scale anisotropies (the harmonic dipole and
quadrupole) and (b) correlations with a sample of nearby starburst galaxies and
the 2MRS catalogue tracing stellar mass within~250~Mpc. This analysis updates
our previous results with the most recent available data, notably with the
addition of 3~years of new Telescope Array data. The main finding is a
correlation between the arrival directions of ~of
UHECRs detected with ~EeV by~Auger or with~~EeV by~TA
and the positions of nearby starburst galaxies on a
~angular scale, with a
~post-trial significance, up from obtained in our
previous study.Comment: proceedings of the 6th International Symposium on Ultra High Energy
Cosmic Rays (UHECR2022), 3-7 October 2022, L'Aquila, Ital
MARTA: A high-energy cosmic-ray detector concept with high-accuracy muon measurement
A new concept for the direct measurement of muons in air showers is
presented. The concept is based on resistive plate chambers (RPCs), which can
directly measure muons with very good space and time resolution. The muon
detector is shielded by placing it under another detector able to absorb and
measure the electromagnetic component of the showers such as a water-Cherenkov
detector, commonly used in air shower arrays. The combination of the two
detectors in a single, compact detector unit provides a unique measurement that
opens rich possibilities in the study of air showers.Comment: 11 page
Search for anisotropies in cosmic-ray positrons detected by the PAMELA experiment
The PAMELA detector was launched on board of the Russian Resurs-DK1 satellite
on June 15, 2006. Data collected during the first four years have been used to
search for large-scale anisotropies in the arrival directions of cosmic-ray
positrons. The PAMELA experiment allows for a full sky investigation, with
sensitivity to global anisotropies in any angular window of the celestial
sphere. Data samples of positrons in the rigidity range 10 GV R
200 GV were analyzed. This article discusses the method and the results of the
search for possible local sources through analysis of anisotropy in positron
data compared to the proton background. The resulting distributions of arrival
directions are found to be isotropic. Starting from the angular power spectrum,
a dipole anisotropy upper limit \delta = 0.166 at 95% C.L. is determined.
Additional search is carried out around the Sun. No evidence of an excess
correlated with that direction was found.Comment: The value of the dipole anisotropy upper limit has been changed. The
method is correct but there was a miscalculation in the relative formul
Hotel Theming in China: A Qualitative Study of Practitioners’ Views
Facing increasing competition, many hotels have adopted “theming” as a marketing strategy. Although still in its fledgling stage, hotel theming has already gained popularity in the growing Chinese hotel market. This study conducted focus group discussions to understand the concepts behind hotel theming in China. Respondents were 41 practitioners from the Chinese hotel industry, who were enrolled in an executive graduate program. Data revealed that hotel theming has four analytical dimensions, namely, the current state, perceived facilitators, inhibitors, and future prospective for developing such strategy in China. Results showed that the specific traits of the Chinese hotel market are highly important for the success of hotel theming in the given context
Effect of Dapagliflozin on Myocardial Insulin Sensitivity and Perfusion: Rationale and Design of The DAPAHEART Trial
Introduction: Sodium-glucose co-transporter-2 (SGLT-2) inhibitors have been shown to have beneficial effects on various cardiovascular (CV) outcomes in patients with type 2 diabetes (T2D) in primary prevention and in those with a high CV risk profile. However, the mechanism(s) responsible for these CV benefits remain elusive and unexplained. The aim of the DAPAHEART study will be to demonstrate that treatment with SGLT-2 inhibitors is associated with greater myocardial insulin sensitivity in patients with T2D, and to determine whether this improvement can be attributed to a decrease in whole-body (and tissue-specific) insulin resistance and to increased myocardial perfusion and/or glucose uptake. We will also determine whether there is an appreciable degree of improvement in myocardial-wall conditions subtended by affected and non-affected coronary vessels, and if this relates to changes in left ventricular function. Methods: The DAPAHEART trial will be a phase III, single-center, randomized, two-arm, parallel-group, double-blind, placebo-controlled study. A cohort of 52 T2D patients with stable coronary artery disease (without any previous history of myocardial infarction, with or without previous percutaneous coronary intervention), with suboptimal glycemic control (glycated hemoglobin [HbA1c] 7\u20138.5%) on their current standard of care anti-hyperglycemic regimen, will be randomized in a 1:1 ratio to dapagliflozin or placebo. The primary outcome is to detect changes in myocardial glucose uptake from baseline to 4 weeks after treatment initiation. The main secondary outcome will be changes in myocardial blood flow, as measured by 13N-ammonia positron emission tomography/computed tomography (PET/CT). Other outcomes include cardiac function, glucose uptake in skeletal muscle, adipose tissue, liver, brain and kidney, as assessed by fluorodeoxyglucose (FDG) PET-CT imaging during hyperinsulinemic-euglycemic clamp; pericardial, subcutaneous and visceral fat, and browning as observed on CT images during FDG PET-CT studies; systemic insulin sensitivity, as assessed by hyperinsulinemic-euglycemic clamp, glycemic control, urinary glucose output; and microbiota modification. Discussion: SGLT-2 inhibitors, in addition to their insulin-independent plasma glucose-lowering effect, are able to directly (substrate availability, fuel utilization, insulin sensitivity) as well as indirectly (cardiac after-load reduction, decreased risk factors for heart failure) affect myocardial functions. Our study will provide novel insights into how these drugs exert CV protection in a diabetic population. Trial registration: EudraCT No. 2016-003614-27; ClinicalTrials.gov Identifier: NCT03313752
Dapagliflozin treatment is associated with a reduction of epicardial adipose tissue thickness and epicardial glucose uptake in human type 2 diabetes
Objective: We recently demonstrated that treatment with sodium-glucose cotransporter-2 inhibitors (SGLT-2i) leads to an increase in myocardial flow reserve in patients with type 2 diabetes (T2D) with stable coronary artery disease (CAD). The mechanism by which this occurs is, however, unclear. One of the risk factors for cardiovascular disease is inflammation of epicardial adipose tissue (EAT). Since the latter is often increased in type 2 diabetes patients, it could play a role in coronary microvascular dysfunction. It is also well known that SGLT-2i modify adipose tissue metabolism. We aimed to investigate the effects of the SGLT-2i dapagliflozin on metabolism and visceral and subcutaneous adipose tissue thickness in T2D patients with stable coronary artery disease and to verify whether these changes could explain observed changes in myocardial flow. Methods: We performed a single-center, prospective, randomized, double-blind, controlled clinical trial with 14 T2D patients randomized 1:1 to SGLT-2i dapagliflozin (10 mg daily) or placebo. The thickness of visceral (epicardial, mediastinal, perirenal) and subcutaneous adipose tissue and glucose uptake were assessed at baseline and 4 weeks after treatment initiation by 2-deoxy-2-[18F]fluoro-D-glucose Positron Emission Tomography/Computed Tomography during hyperinsulinemic euglycemic clamp. Results: The two groups were well-matched for baseline characteristics (age, diabetes duration, HbA1c, BMI, renal and heart function). Dapagliflozin treatment significantly reduced EAT thickness by 19% (p = 0.03). There was a significant 21.6% reduction in EAT glucose uptake during euglycemic hyperinsulinemic clamp in the dapagliflozin group compared with the placebo group (p = 0.014). There were no significant effects on adipose tissue thickness/metabolism in the other depots explored. Conclusions: SGLT-2 inhibition selectively reduces EAT thickness and EAT glucose uptake in T2D patients, suggesting a reduction of EAT inflammation. This could explain the observed increase in myocardial flow reserve, providing new insights into SGLT-2i cardiovascular benefits
The sub-TeV transient Gamma-Ray sky: challenges and opportunities
The detection of gravitational waves and neutrinos from astrophysical sources
with gamma-ray counterparts officially started the era of Multi-Messenger
Astronomy. Their transient and extreme nature implies that monitoring the VHE
sky is fundamental to investigate the non-electromagnetic signals. However, the
limited effective area of space-borne instruments prevents observations above a
few hundred GeV, while the small field of view and low duty cycle of IACTs make
them unsuited for extensive monitoring activities and prompt response to
transients. Extensive Air Shower arrays (EAS) can provide a large field of
view, a wide effective area and a very high duty cycle. Their main difficulty
is the distinction between gamma-ray and cosmic-ray initiated air showers,
especially below the TeV range. Here we present some case studies stressing the
importance that a new EAS array in the Southern Hemisphere will be able to
survey the sky from below 100 GeV up to several TeV. In the energy domain
between 100 and 400 GeV we expect the strongest electromagnetic signatures of
the acceleration of ultra-relativistic particles in sources like SNRs, blazar
jets and gamma-ray bursts, as recently proved by IACT observations. This
spectral window is also crucial to understand the Universe opacity to high
energy radiation, thus providing constraints on the cosmological parameters. We
will discuss the implications of VHE radiation on the mechanisms at work and we
will focus on the advantages resulting from the ability to monitor the energy
window lying between the domain of space-borne detectors and ground-based
facilities
UHECR results of combined analyses of TA and Auger experiments
The origin of ultra-high-energy cosmic rays (UHECRs) is still unknown. Their sources are believed to be within the local universe (a few hundred megaparsecs), but deflections by intergalactic and Galactic magnetic fields prevent us from straightforwardly associating UHECRs to their sources based on their arrival directions, making their angular distribution mostly isotropic. At higher energies, the number of potential source candidates and the magnetic deflections are both expected to be smaller, but so is the available amount of statistics. Hence, it is interesting to perform searches for anisotropies using several different energy thresholds. With a threshold of 8 EeV a dipole modulation has been discovered, and with higher thresholds evidence is mounting for correlations with certain nearby galaxies. Neither of the two main UHECR detectors, the Pierre Auger Observatory and the Telescope Array project, has full-sky coverage. Full-sky searches require combining the datasets of both, and a working group with members of both collaborations has been tasked with this. We present an overview of the challenges encountered in such analyses, recent results from the working group, possible ways of interpreting them, and an outlook for the near future
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