The current study assesses the feasibility and value of crushed cerebral blood flow (CBFcrushed) and arterial transit time (ATT) estimations for large clinical imaging studies in elderly with ...hypertension.
Two pseudo-continuous arterial spin labeling (ASL) scans with (CBFcrushed) and without flow crushers (CBFnon-crushed) were performed in 186 elderly with hypertension, from which CBF and ATT maps were calculated. Standard flow territory maps were subdivided into proximal, intermediate and distal flow territories, based on the measured ATT. The coefficient of variation (CV) and physiological correlations with age and gender were compared between the three perfusion parameters.
There was no difference in CV between CBFcrushed and CBFnon-crushed (15-24%, p>0.4) but the CV of ATT (4-9%) was much smaller. The total gray matter correlations with age and gender were most significant with ATT (p = .016 and p<.001 respectively), in between for CBFcrushed (p = .206 and p = .019) and least significant for CBFnon-crushed (p = .236 and p = .100).
These data show the feasibility and added value of combined measurements of both crushed CBF and ATT for group analyses in elderly with hypertension. The obtained flow territories provide knowledge on vascular anatomy of elderly with hypertension and can be used in future studies to investigate regional vascular effects.
Spin-exchanging interactions govern the properties of strongly correlated electron systems such as many magnetic materials. When orbital degrees of freedom are present, spin exchange between ...different orbitals often dominates, leading to the Kondo effect, heavy fermion behaviour or magnetic ordering. Ultracold ytterbium or alkaline-earth ensembles have attracted much recent interest as model systems for these effects, with two (meta-) stable electronic configurations representing independent orbitals. We report the observation of spin-exchanging contact interactions in a two-orbital SU(N)-symmetric quantum gas realized with fermionic 173Yb. We find strong inter-orbital spin exchange by spectroscopic characterization of all interaction channels and demonstrate SU(N = 6) symmetry within our measurement precision. The spin-exchange process is also directly observed through the dynamic equilibration of spin imbalances between ensembles in separate orbitals. The realization of an SU(N)-symmetric two-orbital Hubbard Hamiltonian opens the route to quantum simulations with extended symmetries and with orbital magnetic interactions, such as the Kondo lattice model.
To describe accurately the pattern, timing, and predictors of disease recurrence after a potentially curative resection for pancreatic ductal adenocarcinoma (PDAC).
After surgery for PDAC, most ...patients will develop disease recurrence. Understanding the patterns and timing of disease failure can help guide improvements in therapy.
Patients who underwent pancreatectomy for PDAC at the Johns Hopkins Hospital between 2000 and 2010 were included. Exclusion criteria were incomplete follow-up records, follow-up <24 months, and neoadjuvant therapy. The first recurrence site was recorded and recurrence-free survival (RFS) was estimated using Kaplan-Meier curves. Predictive factors for specific recurrence patterns were assessed by univariate and multivariate analyses using Cox-proportional hazard regression models.
From the identified cohort of 1103 patients, 692 patients had comprehensive and detailed follow-up data available. At a median follow-up of 25.3 months, 531 (76.7%) of the 692 had recurred after a median RFS of 11.7 months. Most patients recurred at isolated distant sites (n = 307, 57.8%), while isolated local recurrence was seen in 126 patients (23.7%). Liver-only recurrence (n = 134, 25.2%) tended to occur early (median 6.9 mo), while lung-only recurrence (n = 78, 14.7%) occurred later (median 18.6 mo). A positive lymph node ratio >0.2 was a strong predictor for all distant disease recurrence. Patients receiving adjuvant chemotherapy or chemoradiotherapy had fewer recurrences and a longer RFS of 18.0 and 17.2 months, respectively.
Specific recurrence locations have different predictive factors and possess distinct RFS curves, supporting the hypothesis that unique biological differences exist among tumors leading to distinct patterns of recurrence.
We present new 0.6-10 GHz observations of the binary neutron star merger GW170817 covering the period up to 300 days post-merger, taken with the upgraded Karl G. Jansky Very Large Array, the ...Australia Telescope Compact Array, the Giant Metrewave Radio Telescope and the MeerKAT telescope. We use these data to precisely characterize the decay phase of the late-time radio light curve. We find that the temporal decay is consistent with a power-law slope of t−2.2, and that the transition between the power-law rise and decay is relatively sharp. Such a slope cannot be produced by a quasi-isotropic (cocoon-dominated) outflow, but is instead the classic signature of a relativistic jet. This provides strong observational evidence that GW170817 produced a successful jet, and directly demonstrates the link between binary neutron star mergers and short-hard gamma-ray bursts. Using simple analytical arguments, we derive constraints on the geometry and the jet opening angle of GW170817. These results are consistent with those from our companion very long baseline interferometry paper, reporting superluminal motion in GW170817.
Patients with polycystic ovary syndrome (PCOS) are at risk of arterial disease. We examined the risk of (non)fatal coronary heart disease (CHD) or stroke in patients with PCOS and ovulatory women ...without PCOS, and assessed whether obesity might explain a higher risk of CHD or stroke.
We performed a systematic review and meta-analysis of controlled observational studies. Four definitions of PCOS were considered: World Health Organization type II anovulation, National Institutes of Health criteria, Rotterdam consensus and Androgen-excess criteria. Obesity was defined as BMI > 30 kg/m(2) and/or waist circumference >88 cm. Study quality was assessed using the Newcastle-Ottawa Scale. Primary outcome was fatal/non-fatal CHD or stroke. Definitions of CHD and stroke were based on criteria used by the various authors. The effect measure was the pooled relative risk in a random effects model. Risk ratios and rate ratios were combined here.
After identifying 1340 articles, 5 follow-up studies published between 2000 and 2008 were included. The studies showed heterogeneity in design, definitions and quality. In a random effects model the relative risk for CHD or stroke were 2.02 comparing women with PCOS to women without PCOS (95% confidence interval 1.47, 2.76). Pooling the two studies with risk estimates adjusted for BMI showed a relative risk of 1.55 (1.27, 1.89).
This meta-analysis showed a 2-fold risk of arterial disease for patients with PCOS relative to women without PCOS. BMI adjustment did not affect this finding, suggesting the increased risk for cardiovascular events in PCOS is not completely related to a higher BMI in patients with PCOS.
The aim of the study was to identify the survival of patients with locally advanced pancreatic cancer (LAPC) and assess the effect of surgical resection after neoadjuvant therapy on patient outcomes.
...An increasing number of LAPC patients who respond favorably to neoadjuvant therapy undergo surgical resection. The impact of surgery on patient survival is largely unknown.
All LAPC patients who presented to the institutional pancreatic multidisciplinary clinic (PMDC) from January 2013 to September 2017 were included in the study. Demographics and clinical data on neoadjuvant treatment and surgical resection were documented. Primary tumor resection rates after neoadjuvant therapy and overall survival (OS) were the primary study endpoints.
A total of 415 LAPC patients were included in the study. Stratification of neoadjuvant therapy in FOLFIRINOX-based, gemcitabine-based, and combination of the two, and subsequent outcome comparison did not demonstrate significant differences in OS of 331 non-resected LAPC patients (P = 0.134). Eighty-four patients underwent resection of the primary tumor (20%), after a median duration of 5 months of neoadjuvant therapy. FOLFIRINOX-based therapy and stereotactic body radiation therapy correlated with increased probability of resection (P = 0.006). Resected patients had better performance status, smaller median tumor size (P = 0.029), and lower median CA19-9 values (P < 0.001) at PMDC. Patients who underwent surgical resection had significant higher median OS compared with those who did not (35.3 vs 16.3 mo, P < 0.001). The difference remained significant when non-resected patients were matched for time of neoadjuvant therapy (19.9 mo, P < 0.001).
Surgical resection of LAPC after neoadjuvant therapy is feasible in a highly selected cohort of patients (20%) and is associated with significantly longer median overall survival.
Summary
Background
Antiplatelet therapy is the standard treatment for the prevention of cardiovascular events (CVEs). High on‐treatment platelet reactivity (HPR) is a risk factor for secondary CVEs ...in patients prescribed aspirin and/or clopidogrel. The present review and meta‐analysis was aimed at assessing the ability of individual platelet‐function tests to reliably identify patients at risk of developing secondary CVEs.
Methods and Results
A systematic literature search was conducted to identify studies on platelet‐reactivity measurements and CVEs. The main inclusion criteria were: (i) prospective study design; (ii) study medication, including aspirin and/or clopidogrel; and (iii) a platelet‐function test being performed at baseline, before follow‐up started. Of 3882 identified studies, 102 (2.6%; reporting on 44 098 patients) were included in the meta‐analysis. With regard to high on‐aspirin platelet reactivity (HAPR), 22 different tests were discussed in 55 studies (22 441 patients). Pooled analysis showed that HAPR was diagnosed in 22.2% of patients, and was associated with an increased CVE risk (relative risk RR 2.09; 95% confidence interval CI 1.77–2.47). Eleven HAPR tests independently showed a significantly increased CVE risk in patients with HAPR as compared with those with normal on‐aspirin platelet reactivity. As regards high on‐clopidogrel platelet reactivity (HCPR), 59 studies (34 776 patients) discussed 15 different tests, and reported that HCPR was present in 40.4% of patients and was associated with an increased CVE risk (RR 2.80; 95% CI 2.40–3.27). Ten tests showed a significantly increased CVE risk.
Conclusions
Patients with HPR are suboptimally protected against future cardiovascular complications. Furthermore, not all of the numerous platelet tests proved to be able to identify patients at increased cardiovascular risk.
New clinical, laboratory and experimental insights, since the 1999 publication of the Sapporo preliminary classification criteria for antiphospholipid syndrome (APS), had been addressed at a workshop ...in Sydney, Australia, before the Eleventh International Congress on antiphospholipid antibodies. In this document, we appraise the existing evidence on clinical and laboratory features of APS addressed during the forum. Based on this, we propose amendments to the Sapporo criteria. We also provide definitions on features of APS that were not included in the updated criteria.
The phytohormone salicylic acid (SA) is well known for its induction of pathogenesis-related proteins and systemic acquired resistance; SA also has specific effects on plant growth and development. ...Here we analyzed the effect of SA on Arabidopsis (
) root development. We show that exogenous SA treatment at low (below 50 µM) and high (greater than 50 µM) concentrations affect root meristem development in two different PR1-independent ways. Low-concentration SA promoted adventitious roots and altered architecture of the root apical meristem, whereas high-concentration SA inhibited all growth processes in the root. All exposures to exogenous SA led to changes in auxin synthesis and transport. A wide range of SA treatment concentrations activated auxin synthesis, but the effect of SA on auxin transport was dose dependent. Mathematical modeling of auxin synthesis and transport predicted auxin accumulation or depletion in the root tip following low- or high-concentration SA treatments, respectively. SA-induced auxin accumulation led to the formation of more layers of columella initials, an additional cortical cell layer (middle cortex), and extra files of epidermis, cortex, and endodermis cells. Suppression of SHORT ROOT and activation of CYCLIN D6;1 mediated the changes in radial architecture of the root. We propose that low-concentration SA plays an important role in shaping root meristem structure and root system architecture.
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