Retroperitoneal iliac procedures can enable successful endovascular repair of abdominal aortic aneurysm (AAA) in patients who otherwise would not be anatomically eligible. The purpose of this study ...was to determine perioperative outcome with adjunctive retroperitoneal procedures compared with standard bilateral femoral exposure.
Between August 1997 and November 2002, 164 patients underwent elective endovascular AAA repair at a single university medical center. Anatomic, demographic, and early postoperative outcome data gathered prospectively were analyzed. Thirty-two patients (20%) underwent 38 separate adjunctive retroperitoneal procedures. Indications included small external iliac arteries (16 of 32 patients; 50%) and concomitant iliac aneurysm that precluded fixation of the endograft limbs in the common iliac arteries (16 of 32 patients; 50%). The 38 procedures consisted of 8 iliac conduits only, 14 iliac conduits with iliofemoral bypass grafts, and 16 hypogastric revascularization procedures. Data for the study patients were compared with data for 132 patients who underwent endovascular AAA repair through femoral incisions. Primary end points were hospital length of stay, and early morbidity and mortality.
Retroperitoneal procedures enabled an additional 14% of patients with AAA to undergo endovascular techniques. However, there was a significantly higher proportion of women and patients at high risk for anesthesia (American Society of Anesthesiologists class IV or higher) in the group who underwent retroperitoneal procedures. On average, retroperitoneal procedures were associated with 2.6-fold greater blood loss, 82% longer procedure time, 1.5 days additional hospital stay, and 1.8-fold higher rate of perioperative complications, compared with endovascular AAA repair with femoral exposure alone. In contrast, early mortality was similar in the two groups.
Adjunctive retroperitoneal procedures during endovascular AAA repair are associated with increased risk for complications and longer hospital length of stay, compared with AAA repair with standard femoral exposure only. They do not, however, increase early mortality, even in patients at high risk, and enable a larger subset of patients with AAA to undergo endovascular repair.
Objectives
The aim of the present study was to measure brain phosphorus‐31 magnetic resonance spectroscopy (31P MRS) metabolite levels and the creatine kinase reaction forward rate constant (kf) in ...subjects with bipolar disorder (BD).
Methods
Subjects with bipolar euthymia (n = 14) or depression (n = 11) were recruited. Healthy comparison subjects (HC) (n = 23) were recruited and matched to subjects with BD on age, gender, and educational level. All studies were performed on a 3‐Tesla clinical magnetic resonance imaging system using a 31P/1H double‐tuned volume head coil. 31P spectra were acquired without 1H‐decoupling using magnetization‐transfer image‐selected in vivo spectroscopy. Metabolite ratios from a brain region that includes the frontal lobe, corpus callosum, thalamus, and occipital lobe are expressed as a percentage of the total phosphorus (TP) signal. Brain pH was also investigated.
Results
Beta‐nucleoside‐triphosphate (β‐NTP/TP) in subjects with bipolar depression was positively correlated with kf (p = 0.039, r2 = 0.39); similar correlations were not observed in bipolar euthymia or HC. In addition, no differences in kf and brain pH were observed among the three diagnostic groups. A decrease in the ratio of phosphomonoesters to phosphodiesters (PME/PDE) was observed in subjects with bipolar depression relative to HC (p = 0.032). We also observed a trend toward an inverse correlation in bipolar depression characterized by decreased phosphocreatine and increased depression severity.
Conclusions
In our sample, kf was not altered in the euthymic or depressed mood state in BD. However, decreased PME/PDE in subjects with bipolar depression was consistent with differences in membrane turnover. These data provide preliminary support for alterations in phospholipid metabolism and mitochondrial function in bipolar depression.
Dyspnea and reduced exercise capacity, caused, in part, by respiratory muscle dysfunction, are common symptoms in patients with heart failure (HF). However, the etiology of diaphragmatic dysfunction ...has not been identified. To investigate the effects of HF on diaphragmatic function, models of HF were surgically induced in CD-1 mice by transverse aortic constriction (TAC) and acute myocardial infarction (AMI), respectively. Assessment of myocardial function, isolated diaphragmatic strip function, myofilament force-pCa relationship, and phosphorylation status of myofilament proteins was performed at either 2 or 18 wk postsurgery. Echocardiography and invasive hemodynamics revealed development of HF by 18 wk postsurgery in both models. In vitro diaphragmatic force production was preserved in all groups while morphometric analysis revealed diaphragmatic atrophy and fibrosis in 18 wk TAC and AMI groups. Isometric force-pCa measurements of myofilament preparations revealed reduced Ca(2+) sensitivity of force generation and force generation at half-maximum and maximum Ca(2+) activation in 18 wk TAC. The rate of force redevelopment (ktr) was reduced in all HF groups at high levels of Ca(2+) activation. Finally, there were significant changes in the myofilament phosphorylation status of the 18 wk TAC group. This includes a decrease in the phosphorylation of troponin T, desmin, myosin light chain (MLC) 1, and MLC 2 as well as a shift in myosin isoforms. These results indicate that there are multiple changes in diaphragmatic myofilament function, which are specific to the type and stage of HF and occur before overt impairment of in vitro force production.
Malarial merozoites use an array of ligands, including members of the Reticulocyte Binding Like (RBL) super-family of invasion proteins, to identify and invade erythrocytes. RBL family members are ...large Type I membrane anchored proteins expressed at the invasive end of merozoites that share homology with the Reticulocyte Binding Proteins 1 and 2 (PvRBP1 and 2) of
Plasmodium vivax.
Plasmodium species vary widely both in the number and sequence of their
RBL genes, with the recently completed
Plasmodium falciparum genome containing five
RBL genes. Of these, three encode proteins shown to be involved in erythrocyte invasion, a fourth is a pseudogene, and the role of the fifth is as yet unclear. In order to identify sequence similarities and differences that may have functional implications for erythrocyte invasion as well as to gain insights into the recent evolutionary history of the
P. falciparum RBL genes, we have sequenced all five corresponding
RBL genes from the chimpanzee parasite
Plasmodium reichenowi, which is the closest phylogenetic relative of
P. falciparum, yet is unable to invade human erythrocytes. Two of the five
P. falciparum RBL genes have highly conserved complete open reading frames in both species, while the other three genes show evidence of gene conversion and rapid evolution. The RBL super-family, therefore, appears to be surprisingly dynamic and divergent, implying that it is involved in species-specific aspects of erythrocyte recognition and invasion.
HOLISMOKES Suyu, S. H.; Huber, S.; Cañameras, R. ...
Astronomy and astrophysics (Berlin),
12/2020, Letnik:
644
Journal Article, Web Resource
Recenzirano
Odprti dostop
We present the HOLISMOKES programme on strong gravitational lensing of supernovae (SNe) as a probe of SN physics and cosmology. We investigate the effects of microlensing on early-phase SN Ia spectra ...using four different SN explosion models. We find that distortions of SN Ia spectra due to microlensing are typically negligible within ten rest-frame days after a SN explosion (< 1% distortion within the 1
σ
spread and ≲10% distortion within the 2
σ
spread). This shows the great prospects of using lensed SNe Ia to obtain intrinsic early-phase SN spectra for deciphering SN Ia progenitors. As a demonstration of the usefulness of lensed SNe Ia for cosmology, we simulate a sample of mock lensed SN Ia systems that are expected to have accurate and precise time-delay measurements in the era of the
Rubin
Observatory Legacy Survey of Space and Time (LSST). Adopting realistic yet conservative uncertainties on their time-delay distances and lens angular diameter distances, of 6.6% and 5%, respectively, we find that a sample of 20 lensed SNe Ia would allow us to constrain the Hubble constant (
H
0
) with 1.3% uncertainty in the flat ΛCDM cosmology. We find a similar constraint on
H
0
in an open ΛCDM cosmology, while the constraint degrades to 3% in a flat
w
CDM cosmology. We anticipate lensed SNe to be an independent and powerful probe of SN physics and cosmology in the upcoming LSST era.
We performed a comparative study on the interaction modes of 2‐haloimidazolium salts with anions in solution, particularly with regard to halogen bonding, hydrogen bonding and anion–π interactions. ...The syntheses and solid‐state analyses of a series of sterically and electronically modified 2‐haloimidazolium structures are presented. Detailed isothermal titration calorimetry (ITC) measurements, quantum mechanics/molecular mechanics (QM/MM), classical molecular dynamics simulations (MD) and free‐energy calculations together with NMR spectroscopy were used to elucidate the binding modes in solution. Our work reveals the absence of a potential anion–π interaction between the cationic imidazolium ring and the Lewis basic counteranion, and corroborates a formation of halogen bonding via the Lewis acidic iodine moiety and hydrogen bonding via the backbone hydrogen atoms, with repercussions in the field of organocatalysis.
XB, or not XB, that is the question: The interaction modes of 2‐haloimidazolium salts (as prototypical halogen bond donors) with anions in solution was investigated by isothermal titration calorimetry, quantum mechanics/molecular mechanics, classical molecular dynamics simulations as well as with NMR spectroscopy and the findings were compared to X‐ray crystallographic studies.
High-energy gamma-ray emission is theoretically expected to arise in tight binary star systems (with high mass loss and high-velocity winds), although the evidence of this relationship has proven to ...be elusive so far. Here we present the first bounds on this putative emission from isolated Wolf-Rayet (WR) star binaries, WR 147 and WR 146, obtained from observations with the MAGIC telescope. In the unification scheme of Seyfert galaxies, a dusty torus blocks the continuum source and broad-line region in Seyfert 2 galaxies. However it is not clear whether or not and to what extent the torus affects the narrow-line spectra. In this Letter, we show that Seyfert 1 and Seyfert 2 galaxies have different distributions on the O iii/H beta versus N ii/H alpha diagram (BPT diagram) for narrow lines. Seyfert 2 galaxies display a clear left boundary on the BPT diagram and only 7.3% of them lie on the left. By contrast, Seyfert 1 galaxies do not show such a cutoff and 33.0% of them stand on the left side of the boundary. Among Seyfert 1 galaxies, the distribution varies with the extinction to broad lines. As the extinction increases, the distribution on BPT diagram moves to larger N ii/H alpha values. We interpret this as evidence for the obscuration of an inner dense narrow-line region by the dusty torus. We also demonstrate that the O iii and broad-line luminosity correlation depends on the extinction of broad lines in the way that high-extinction objects have lower uncorrected O iii luminosities, suggesting that O iii is partially obscured in these objects. Therefore, using O iii as an indicator for the nuclear luminosity will systematically underestimate the nuclear luminosity of Seyfert 2 galaxies.
The record of terrestrial impact events is incomplete with no Archean impact structures discovered, despite the expected abundance of collisions that must have occurred. Because no Archean impact ...structures have been identified, the necessary conditions to preserve an impact structure longer than 2 Byr are unknown. One significant effect of shock metamorphism is that the physical properties of the target rocks change, resulting in distinctive geophysical signatures of impact structures. To evaluate the preservation potential of impact structures, we evaluate the deeply eroded Proterozoic Vredefort impact structure to examine the changes in physical properties and the remnant of the geophysical signature and compare the results with the well‐preserved Chicxulub impact structure. The major structural features of Vredefort are similar to the expected profile of the Chicxulub structure at a depth of 8–10 km. The Vredefort target rocks, while shocked, do not preserve measurable changes in their physical properties. The gravity signature of the impact structure is minor and is controlled by the remnant of the collapsed transient crater rim and the uplifted Moho surface. We anticipate that erosion of the Vredefort structure by an additional 1 km would remove evidence of impact, and regardless of initial size, erosion by >10 km would result in the removal of most of the evidence for any impact structure from the geological record. This study demonstrates that the identification of geologically old (i.e., Archean) impact structures is limited by a lack of geophysical signatures associated with deeply eroded craters.
Plain Language Summary
Meteorite collisions should have formed throughout the 4.5 billion‐year‐long history of Earth, but we have only found impact craters that are less than half of the age of the Earth (2 billion years) and younger. In order to understand how to find very old impact craters, we studied the largest of the oldest preserved impact craters. The 2 Byr old Vredefort structure in South Africa has been deeply eroded, and thus provides a good view of its deep roots. We collected a series of samples of the exposed rocks known to have evidence of shock effects and measured their physical properties. We found that the physical properties do not show evidence of the meteorite impact event. We also established that the gravity profile of the crater preserves a weak signal. When the Vredefort structure erodes a bit more, the geophysical characteristics that make it identifiable will be gone. We expect that signatures of ancient impact structures even larger than Vredefort would be completely removed by erosion by now. Therefore, to find very old impact craters, we need to look in areas that have experienced unusually little erosion.
Key Points
The target rocks exposed on the surface of the central core of the Vredefort structure do not preserve changes in physical properties
Regardless of initial size, changes in the physical properties of impact structures on Earth might be unidentifiable if they are eroded by more than 10 km
Archean impact structures on Earth can only be identified if extraordinary preservation takes place
Purpose: Aggressive attempts at limb salvage in patients with ischemic tissue loss are justified by favorable initial results in most patients. The identification of patients whose conditions will ...not benefit from attempted revascularization remains difficult.
Methods: This study was designed as a retrospective review of prospectively collected clinical data. The subjects were 210 consecutive patients who underwent infrainguinal vein bypass grafting for ischemic tissue loss in the setting of an academic medical center. Bypass grafting was to the popliteal artery in 56 patients, to the infrapopliteal arteries in 131 patients, and to the pedal arteries in 23 patients. The follow-up examination was complete in 209 of 210 patients. One hundred twenty-five patients underwent blinded review of duplex scan venous mapping and arteriography to determine simplified vein and run-off scores. The outcome measures were the influence of risk factors, venous conduit, and runoff on mortality, limb loss, and graft failure at the 6-month follow-up examination.
Results: One hundred seventy patients (81%) were alive and had limb salvage. Nineteen patients (9.1%) died, with need for a simultaneous inflow procedure and end-stage renal disease being most commonly associated with mortality. Thirty-three patients (15.8%) had undergone amputation: 18 after graft failure, and 15 for progressive tissue loss despite a patent graft. Amputation was significantly more common in patients with diabetes (
P = .05) and with poor runoff scores (poor runoff, 44.4% vs good runoff, 7.4%;
P < .01). Amputation despite a patent graft also correlated with runoff (poor runoff, 41.7% vs good runoff, 4.3%;
P < .01). Twenty-five patients had graft failure without amputation, so that only 145 patients (69.4%) were alive, had limb salvage, and had a patent graft. Run-off score was the strongest predictor of outcome, with 70% of patients with poor run-off scores having death, amputation, or graft failure.
Conclusion: Aggressive use of infrainguinal vein bypass grafting in patients with ischemic tissue loss results in a high rate of initial limb salvage but significant morbidity and mortality. Arteriographically determined runoff scores appear to potentially identify patients at high risk for a poor initial outcome and may provide a method of selecting patients for primary amputation. (J Vasc Surg 1999;30:427-35.)
Using peptides that represent linear regions of the powerful complement activation product, C5a, or loops that connect the four alpha helices of C5a, we have defined the ability of these peptides to ...reduce binding of (125)I-C5a to human neutrophils, inhibit chemotactic responses of neutrophils to C5a, and reduce H(2)O(2) production in neutrophils stimulated with PMA. The data have defined likely sites of interaction of C5a with C5aR. The peptides had no functional activity per se on neutrophils and did not interfere with neutrophil responses to the unrelated chemotactic peptide, N-formyl-Met-Leu-Phe. Although previous data have suggested that there are two separate sites on C5a reactive with C5aR, the current data suggest that C5a interacts with C5aR in a manner that engages three discontinuous regions of C5a.
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