Expansion of the Multi-Link Frontier™ coronary bifurcation stent: micro-computed tomographic assessment in human autopsy and porcine heart samples

Background

Treatment of coronary bifurcation lesions remains challenging, beyond the introduction of drug eluting stents. Dedicated stent systems are available to improve the technical approach to the treatment of these lesions. However dedicated stent systems have so far not reduced the incidence of stent restenosis. The aim of this study was to assess the expansion of the Multi-Link (ML) Frontier™ stent in human and porcine coronary arteries to provide the cardiologist with useful in-vitro information for stent implantation and selection.

Methodology/Principal Findings

Nine ML Frontier™ stents were implanted in seven human autopsy heart samples with known coronary artery disease and five ML Frontier™ stents were implanted in five porcine hearts. Proximal, distal and side branch diameters (PD, DD, SBD, respectively), corresponding opening areas (PA, DA, SBA) and the mean stent length (L) were assessed by micro-computed tomography (micro-CT). PD and PA were significantly smaller in human autopsy heart samples than in porcine heart samples (3.54±0.47 mm vs. 4.04±0.22 mm, p = 0.048; 10.00±2.42 mm² vs. 12.84±1.38 mm², p = 0.034, respectively) and than those given by the manufacturer (3.54±0.47 mm vs. 4.03 mm, p = 0.014). L was smaller in human autopsy heart samples than in porcine heart samples, although data did not reach significance (16.66±1.30 mm vs. 17.30±0.51 mm, p = 0.32), and significantly smaller than that given by the manufacturer (16.66±1.30 mm vs. 18 mm, p = 0.015).

Conclusions/Significance

Micro-CT is a feasible tool for exact surveying of dedicated stent systems and could make a contribution to the development of these devices. The proximal diameter and proximal area of the stent system were considerably smaller in human autopsy heart samples than in porcine heart samples and than those given by the manufacturer. Special consideration should be given to the stent deployment procedure (and to the follow-up) of dedicated stent systems, considering final intravascular ultrasound or optical coherence tomography to visualize (and if necessary optimize) stent expansion.     

Reduction in cricket (Orthoptera: Ensifera) populations along a gradient of sulphur dioxide from mining emissions in northern Australia

The impact of SO₂ dry deposition from mining emissions on cricket abundance, diversity and composition was investigated at Mount Isa in the semiarid tropics of northern Australia. Seventy-one sites were sampled, stratified at two levels: sulphur deposition zones (high, medium, low, and background zones) and habitat (rocky ridge, rocky plain and alluvial plain). The three habitats did not support distinctly different cricket assemblages. Crickets responded to SO₂ emissions, but impacts were largely restricted to the high-sulphur zone. Generalised linear modelling showed significant reductions in the probability of presence in the high-sulphur zone for the three genera Eurepella, Salmanites and Endacusta , and the subfamily Eneopterinae. In ordination space, the three high-sulphur zone by habitat combinations were clearly separated from all other combinations, and vector fitting of environmental variables showed soil SO₄ to be a primary correlative factor of this separation. Crickets are sensitive to SO₂ emissions and they appear to be a good indicator group in this context.     

Assembly of the mariner Mos1 synaptic complex

The mobility of transposable elements via a cut-and-paste mechanism depends on the elaboration of a nucleoprotein complex known as the synaptic complex. We show here that the Mos1 synaptic complex consists of the two inverted terminal repeats of the element brought together by a transposase tetramer and is designated paired-end complex 2 (PEC2). The assembly of PEC2 requires the formation of a simpler complex, containing one terminal repeat and two transposase molecules and designated single-end complex 2 (SEC2). In light of the formation of SEC2 and PEC2, we demonstrate the presence of two binding sites for the transposase within a single terminal repeat. We have found that the sequence of the Mos1 inverted terminal repeats contains overlapping palindromic and mirror motifs, which could account for the binding of two transposase molecules "side by side" on the same inverted terminal repeat. We provide data indicating that the Mos1 transposase dimer is formed within a single terminal repeat through a cooperative pathway. Finally, the concept of a tetrameric synaptic complex may simply account for the inability of a single mariner transposase molecule to interact at the same time with two kinds of DNA: the inverted repeat and the target DNA.     

Hypoxia-inducible factors 1alpha and 2alpha regulate trophoblast differentiation

Placental development initially occurs in a low-oxygen (O2) or hypoxic environment. In this report we show that two hypoxia-inducible factors (HIFs), HIF1alpha and HIF2alpha, are essential for determining murine placental cell fates. HIF is a heterodimer composed of HIFalpha and HIFbeta (ARNT) subunits. Placentas from Arnt-/- and Hif1alpha-/- Hif2alpha-/- embryos exhibit defective placental vascularization and aberrant cell fate adoption. HIF regulation of Mash2 promotes spongiotrophoblast differentiation, a prerequisite for trophoblast giant cell differentiation. In the absence of Arnt or Hifalpha, trophoblast stem cells fail to generate these cell types and become labyrinthine trophoblasts instead. Therefore, HIF mediates placental morphogenesis, angiogenesis, and cell fate decisions, demonstrating that O2 tension is a critical regulator of trophoblast lineage determination. This novel genetic approach provides new insights into the role of O2 tension in the development of life-threatening pregnancy-related diseases such as preeclampsia.     

Historical transoceanic dispersal of a freshwater shrimp: the colonization of the South Pacific by the genus Paratya (Atyidae)

Aim To infer the phylogenetic relationships within the freshwater shrimp genus Paratya Miers, 1882 (Atyidae) and to use these data to answer biogeographical questions about the location, timing and form of evolution of this genus in the South Pacific. Location Paratya are spread throughout various freshwater habitats in the western Pacific, with a disjunct northern range in the North Pacific (Japan, Korea, Ryukyu Islands, Siberia) and South Pacific (Australia, New Zealand, New Caledonia, Lord Howe, Norfolk Island). Methods Specimens were obtained from throughout its range. Mitochondrial sequences of cytochrome oxidase subunit I and 16S ribosomal DNA were analysed using phylogenetic techniques to identify whether landmasses are monophyletic and what the relationships are between landmasses. Molecular clock dating methods were used to date divergences between taxa. Results Each landmass was recovered as monophyletic. Japan/Ryukyu Islands is the most basal group, followed by New Zealand. Australian specimens form a sister group to a clade made up of two groups (New Caledonia and Lord Howe/Norfolk Island). The oldest divergence within the genus (between North and South Pacific) took place 12–19 Ma. Main conclusions The geographical origin of the genus (either Gondwana or Laurasia) is unclear. Dispersal occurred between the North and South Pacific long after the split up of Gondwana. Dispersal likely explains the presence of Paratya on each landmass in the South Pacific, from continent to isolated oceanic island. This dispersal is conjectured to have taken place through oceanic currents because of the amphidromous life cycle of some taxa of Paratya, given that amphyidromy is plesiomorphic in atyid shrimp.     

Patients' satisfaction with prosthetic devices

The purpose of the paper was to ascertain the factors which affect the satisfaction of patients with the prosthetic therapy. The purpose of the paper was also to ascertain if there are common factors characteristic for patients dissatisfied with the prosthetic therapy although the specialist appraises it as objectively successful. 52 patients of the Clinical Institute for Rehabilitation and Orthopedic Devices were participating in the research, to which, after unsuccessful surgical-prosthetic rehabilitation, reamputation and prosthetic provision was carried out, which was appraised successful by the doctor. It was endeavored to appraise to what extent the appraisal by the doctor corresponds to patient's satisfaction. On the basis of the questionnaire elaborated specifically for this research and the statistical processing, it was concluded that where the doctor appraised the prosthetic therapy as successful, the same opinion was shared by the majority of the patients (92.3%). Patients are similarly satisfied with the function and the esthetic quality of the prosthesis (73%). The reason why 7.7% of patients are dissatisfied in cases when the doctor considers that there are no objective reasons for that should be sought in non-medical factors. The age, the education, the marital status, the income state, the size of the residence and the regional affiliation do not have a significant influence on the satisfaction of patients with the prosthesis (p > 0.05). Patients with a minor handicap achieve satisfaction with the prosthetic therapy faster, as well as the right-handed persons if the prosthesis on the right-hand extremity is in question (p < 0.05). This investigation showed that the responsibility of not wearing prosthetic aids, both orthopedic, and dental prostheses, couldn't be only neuroticism by prosthetic patients, because that connection is not statistically significant (p < 0.09).     

Effects of gender and hypovolemia on sympathetic neural responses to orthostatic stress

We tested the hypothesis that women have blunted sympathetic neural responses to orthostatic stress compared with men, which may be elicited under hypovolemic conditions. Muscle sympathetic nerve activity (MSNA) and hemodynamics were measured in eight healthy young women and seven men in supine position and during 6 min of 60 degrees head-up tilt (HUT) under normovolemic and hypovolemic conditions (randomly), with approximately 4-wk interval. Acute hypovolemia was produced by diuretic (furosemide) administration approximately 2 h before testing. Orthostatic tolerance was determined by progressive lower body negative pressure to presyncope. We found that furosemide produced an approximately 13% reduction in plasma volume, causing a similar increase in supine MSNA in men and women (mean +/- SD of 5 +/- 7 vs. 6 +/- 5 bursts/min; P = 0.895). MSNA increased during HUT and was greater in the hypovolemic than in the normovolemic condition (32 +/- 6 bursts/min in normovolemia vs. 44 +/- 15 bursts/min in hypovolemia in men, P = 0.055; 35 +/- 9 vs. 45 +/- 8 bursts/min in women, P < 0.001); these responses were not different between the genders (gender effect: P = 0.832 and 0.814 in normovolemia and hypovolemia, respectively). Total peripheral resistance increased proportionately with increases in MSNA during HUT; these responses were similar between the genders. However, systolic blood pressure was lower, whereas diastolic blood pressure was similar in women compared with men during HUT, which was associated with a smaller stroke volume or stroke index. Orthostatic tolerance was lower in women, especially under hypovolemic conditions. These results indicate that men and women have comparable sympathetic neural responses during orthostatic stress under normovolemic and hypovolemic conditions. The lower orthostatic tolerance in women is predominantly because of a smaller stroke volume, presumably due to less cardiac filling during orthostasis, especially under hypovolemic conditions, which may overwhelm the vasomotor reserve available for vasoconstriction or precipitate neurally mediated sympathetic withdrawal and syncope.