3,766 research outputs found
Inhibition of Trophoblast-Induced Spiral Artery Remodeling Reduces Placental Perfusion in Rat Pregnancy.
Rats harboring the human angiotensinogen and human renin genes develop preeclamptic features in pregnancy. The preeclamptic rats exhibit a deeper trophoblast invasion associated with a reduced resistance index by uterine
Doppler. Doxycycline inhibits matrix metalloproteinase activity. We tested the hypothesis that matrix metalloproteinase inhibition reduces trophoblast invasion with subsequent changes in placental perfusion. Preeclamptic and pregnant control Sprague-Dawley rats were treated with doxycycline (30 mg/kg of body weight orally) from gestational day 12 until day 18. Placental perfusion was assessed using a micromarker contrast agent. The animals were euthanized on day 18 of pregnancy; biometric data were acquired, and trophoblast invasion was analyzed. Doxycycline resulted in intrauterine growth retardation and lighter placentas in both groups. Maternal body weight was not affected. As shown earlier, preeclamptic rats exhibited a deeper endovascular trophoblast invasion. However, doxycycline treatment reduced trophoblast invasion in the preeclamptic rats. The physiological spiral artery remodeling, as assessed by the deposition of fibrinoid and α-actin in the spiral artery contour, was significantly reduced by doxycycline. The vascularity index, as assessed by perfusion measurement of the placenta, was reduced after doxycycline treatment in preeclamptic rats. Thus, matrix metalloproteinase inhibition with doxycycline leads to reduced trophoblast invasion and associated reduced placental perfusion. These studies are the first to show that reducing trophoblast-induced vascular remodeling decreases subsequent placental perfusion. Our model allows the study of dysregulated trophoblast invasion and vascular remodeling in vivo to gain important insights into preeclampsia-related mechanisms
Coherent states on the circle
We present a possible construction of coherent states on the unit circle as
configuration space. In our approach the phase space is the product Z x S^1.
Because of the duality of canonical coordinates and momenta, i.e. the angular
variable and the integers, this formulation can also be interpreted as coherent
states over an infinite periodic chain. For the construction we use the analogy
with our quantization over a finite periodic chain where the phase space was
Z_M x Z_M. Properties of the coherent states constructed in this way are
studied and the coherent states are shown to satisfy the resolution of unity.Comment: 7 pages, presented at GROUP28 - "28th International Colloquium on
Group Theoretical Methods in Physics", Newcastle upon Tyne, July 2010.
Accepted in Journal of Physics Conference Serie
Effects of Circulating and Local Uteroplacental Angiotensin II in Rat Pregnancy.
The renin-angiotensin (Ang) system is important during placental development. Dysregulation of the renin-Ang system is important in preeclampsia (PE). Female rats transgenic for the human angiotensinogen gene crossed with males transgenic for the human renin gene develop the PE syndrome, whereas those of the opposite cross do not. We used this model to study the role of Ang II in trophoblast invasion, which is shallow in human PE but deeper in this model. We investigated the following groups: PE rats, opposite-cross rats, Ang II–infused rats (1000 ng/kg per day), and control rats. Ang II infusion increased only circulating Ang II levels (267.82 pg/mL), opposite cross influenced only uteroplacental Ang II (13.52 fmol/mg of protein), and PE increased both circulating (251.09 pg/mL) and uteroplacental (19.24 fmol/mg of protein) Ang II. Blood pressure and albuminuria occurred in the models with high circulating Ang II but not in the other models. Trophoblast invasion increased in PE and opposite-cross rats but not in Ang II–infused rats. Correspondingly, uterine artery resistance index increased in Ang II–infused rats but decreased in PE rats. We then studied human trophoblasts and villous explants from first-trimester pregnancies with time-lapse microscopy. Local Ang II dose-dependently increased migration by 75%, invasion by 58%, and motility by 282%. The data suggest that local tissue Ang II stimulates trophoblast invasion in vivo in the rat and in vitro in human cells, a hitherto fore unrecognized function. Conceivably, upregulation of tissue Ang II in the maternal part of the placenta represents an important growth factor for trophoblast invasion and migration
Sympathetic activity and early mobilization in patients in intensive and intermediate care with severe brain injuries: a preliminary prospective randomized study.
Patients who experience severe brain injuries are at risk of secondary brain damage, because of delayed vasospasm and edema. Traditionally, many of these patients are kept on prolonged bed rest in order to maintain adequate cerebral blood flow, especially in the case of subarachnoid hemorrhage. On the other hand, prolonged bed rest carries important morbidity. There may be a clinical benefit in early mobilization and our hypothesis is that early gradual mobilization is safe in these patients. The aim of this study was to observe and quantify the changes in sympathetic activity, mainly related to stress, and blood pressure in gradual postural changes by the verticalization robot (Erigo®) and after training by a lower body ergometer (MOTOmed-letto®), after prolonged bed rest of minimum 7 days.
Thirty patients with severe neurological injuries were randomized into 3 groups with different protocols of mobilization: Standard, MOTOmed-letto® or Erigo® protocol. We measured plasma catecholamines, metanephrines and blood pressure before, during and after mobilization.
Blood pressure does not show any significant difference between the 3 groups. The analysis of the catecholamines suggests a significant increase in catecholamine production during Standard mobilization with physiotherapists and with MOTOmed-letto® and no changes with Erigo®.
This preliminary prospective randomized study shows that the mobilization of patients with severe brain injuries by means of Erigo® does not increase the production of catecholamines. It means that Erigo® is a well-tolerated method of mobilization and can be considered a safe system of early mobilization of these patients. Further studies are required to validate our conclusions.
The study was registered in the ISRCTN registry with the trial registration number ISRCTN56402432 . Date of registration: 08.03.2016. Retrospectively registered
Treadmill exercise activates subcortical neural networks and improves walking after a stroke
BACKGROUND AND PURPOSE: Stroke often impairs gait thereby reducing mobility and fitness and promoting chronic disability. Gait is a complex sensorimotor function controlled by integrated cortical, subcortical, and spinal networks. The mechanisms of gait recovery after stroke are not well understood. This study examines the hypothesis that progressive task-repetitive treadmill exercise (T-EX) improves fitness and gait function in subjects with chronic hemiparetic stroke by inducing adaptations in the brain (plasticity).METHODS: A randomized controlled trial determined the effects of 6-month T-EX (n=37) versus comparable duration stretching (CON, n=34) on walking, aerobic fitness and in a subset (n=15/17) on brain activation measured by functional MRI.RESULTS: T-EX significantly improved treadmill-walking velocity by 51% and cardiovascular fitness by 18% (11% and -3% for CON, respectively; P<0.05). T-EX but not CON affected brain activation during paretic, but not during nonparetic limb movement, showing 72% increased activation in posterior cerebellar lobe and 18% in midbrain (P<0.005). Exercise-mediated improvements in walking velocity correlated with increased activation in cerebellum and midbrain.CONCLUSIONS: T-EX improves walking, fitness and recruits cerebellum-midbrain circuits, likely reflecting neural network plasticity. This neural recruitment is associated with better walking. These findings demonstrate the effectiveness of T-EX rehabilitation in promoting gait recovery of stroke survivors with long-term mobility impairment and provide evidence of neuroplastic mechanisms that could lead to further refinements in these paradigms to improve functional outcomes
Monitoring and Pay: An Experiment on Employee Performance under Endogenous Supervision
We present an experimental test of a shirking model where monitoring intensity is endogenous and effort a continuous variable. Wage level, monitoring intensity and consequently the desired enforceable effort level are jointly determined by the maximization problem of the firm. As a result, monitoring and pay should be complements. In our experiment, between and within treatment variation is qualitatively in line with the normative predictions of
the model under standard assumptions. Yet, we also find evidence for reciprocal behavior. Our data analysis shows, however, that it does not pay for the employer to solely rely on the reciprocity of employees
Protein trafficking through the endosomal system prepares intracellular parasites for a home invasion
Toxoplasma (toxoplasmosis) and Plasmodium (malaria) use unique secretory organelles for migration, cell invasion, manipulation of host cell functions, and cell egress. In particular, the apical secretory micronemes and rhoptries of apicomplexan parasites are essential for successful host infection. New findings reveal that the contents of these organelles, which are transported through the endoplasmic reticulum (ER) and Golgi, also require the parasite endosome-like system to access their respective organelles. In this review, we discuss recent findings that demonstrate that these parasites reduced their endosomal system and modified classical regulators of this pathway for the biogenesis of apical organelles
Mortality among World Trade Center rescue and recovery workers, 2002-2011
BACKGROUND:
Rescue and recovery workers responding to the 2001 collapse of the World Trade Center (WTC) sustained exposures to toxic chemicals and have elevated rates of multiple morbidities.
METHODS:
Using data from the World Trade Center Health Program and the National Death Index for 2002-2011, we examined standardized mortality ratios (SMR) and proportional cancer mortality ratios (PCMR) with indirect standardization for age, sex, race, and calendar year to the U.S. general population, as well as associations between WTC-related environmental exposures and all-cause mortality.
RESULTS:
We identified 330 deaths among 28,918 responders (SMR 0.43, 95%CI 0.39-0.48). No cause-specific SMRs were meaningfully elevated. PCMRs were elevated for neoplasms of lymphatic and hematopoietic tissue (PCMR 1.76, 95%CI 1.06-2.75). Mortality hazard ratios showed no linear trend with exposure.
CONCLUSIONS:
Consistent with a healthy worker effect, all-cause mortality among responders was not elevated. There was no clear association between intensity and duration of exposure and mortality. Surveillance is needed to monitor the proportionally higher cancer mortality attributed to lymphatic/hematopoietic neoplasms
Digital relief generation from 3D models
It is difficult to extend image-based relief generation to high-relief generation, as the images contain insufficient height information. To generate reliefs from three-dimensional (3D) models, it is necessary to extract the height fields from the model, but this can only generate bas-reliefs. To overcome this problem, an efficient method is proposed to generate bas-reliefs and high-reliefs directly from 3D meshes. To produce relief features that are visually appropriate, the 3D meshes are first scaled. 3D unsharp masking is used to enhance the visual features in the 3D mesh, and average smoothing and Laplacian smoothing are implemented to achieve better smoothing results. A nonlinear variable scaling scheme is then employed to generate the final bas-reliefs and high-reliefs. Using the proposed method, relief models can be generated from arbitrary viewing positions with different gestures and combinations of multiple 3D models. The generated relief models can be printed by 3D printers. The proposed method provides a means of generating both high-reliefs and bas-reliefs in an efficient and effective way under the appropriate scaling factors
A critical perspective on second-order empathy in understanding psychopathology: phenomenology and ethics
The centenary of Karl Jaspers’ General Psychopathology was recognised in 2013 with the publication of a volume of essays dedicated to his work (edited by Stanghellini and Fuchs). Leading phenomenological-psychopathologists and philosophers of psychiatry examined Jaspers notion of empathic understanding and his declaration that certain schizophrenic phenomena are ‘un-understandable’. The consensus reached by the authors was that Jaspers operated with a narrow conception of phenomenology and empathy and that schizophrenic phenomena can be understood through what they variously called second-order and radical empathy. This article offers a critical examination of the second-order empathic stance along phenomenological and ethical lines. It asks: (1) Is second-order empathy (phenomenologically) possible? (2) Is the second-order empathic stance an ethically acceptable attitude towards persons diagnosed with schizophrenia? I argue that second-order empathy is an incoherent method that cannot be realised. Further, the attitude promoted by this method is ethically problematic insofar as the emphasis placed on radical otherness disinvests persons diagnosed with schizophrenia from a fair chance to participate in the public construction of their identity and, hence, to redress traditional symbolic injustices
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