925 resultados para NEURORETINAL RIM
Resumo:
The vascular disrupting agent (VDA) combretastatin A4 phosphate (CA4P) induces significant tumor necrosis as a single agent. Preclinical models have shown that the addition of an anti-VEGF antibody to a VDA attenuates the revascularization of the surviving tumor rim and thus significantly increases antitumor activity.
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Detrital zircon and metamorphic monazite ages from the Picuris Mountains, north central New Mexico, were used to confirm the depositional age of the Marquenas Formation, to document the depositional age of the Vadito Group, and to constrain the timing of metamorphism and deformation in the region. Detrital zircon 207Pb/206Pb ages were obtained with the LA-MC-ICPMS from quartzites collected from the type locality of the Marquenas Formation exposed at Cerro de las Marquenas, and from the lower Vadito Group in the southern and eastern Picuris Mountains. The Marquenas Formation sample yields 113 concordant ages including a Mesoproterozoic age population with four grains ca. 1470 Ga, a broad Paleoproterozoic age peak at 1695 Ma, and minor Archean age populations. Data confirm recent findings of Mesoproterozoic detrital zircons reported by Jones et al. (2011), and show that the Marquenas Formation is the youngest lithostratigraphic unit in the Picuris Mountains. Paleoproterozoic and Archean detrital grains in the Marquenas Formation are likely derived from local recycled Vadito Group rocks and ca. 1.75 Ga plutonic complexes, and ca. 1.46 detrital zircons were most likely derived from exposed Mesoproterozoic plutons south of the Picuris. Ninety-five concordant grains from each of two Vadito Group quartzites yield relatively identical unimodal Paleoproterozoic age distributions, with peaks at 1713-1707 Ma. Eastern exposures of quartzite mapped as Marquenas Formation yield detrital zircon age patterns and metamorphic mineral assemblages that are nearly identical to the Vadito Group. On this basis, I tentatively assigned the easternmost quartzite to the Vadito Group. Zircon grains in all samples show low U/Th ratios, welldeveloped concentric zoning, and no evidence of metamorphic overgrowth events, consistent with an igneous origin. North-directed paleocurrent indicators, such as tangential crossbeds (Soegaard & Eriksson, 1986) and other primary sedimentary structures, are preserved in the Marquenas Formation quartzite. Together with pebble-toboulder metaconglomerates in the Marquenas, these observations suggest that this formation was deposited in a braided alluvial plain environment in response to syntectonic uplift to the south of the Picuris Mountains. Metamorphic monazite from two Vadito Group quartzite samples were analyzed with an electron microprobe (EMP). Elemental compositional variation with respect to Th and Y define core and rim domains in monazite grains, and show lower concentrations of Th (1.46-1.52 wt%) and Y (0.67 wt%) in the cores, and higher concentrations of Th (1.98 wt%) and Y (1.06 wt%) in the rims. Results show that Mesoproterozoic core and rim ages from five grains overlap within uncertainty, ranging from 1395-1469 Ma with an average age of 1444 Ma. This 1.44 Ga average age is the dominant timing of metamorphic monazite growth in the region, and represents the timing of metamorphism experienced by the region. An older 1630 Ma core observed in sample CD10-12 may be interpreted as a result of low temperature metamorphism in lower Vadito Group rocks due to heat from ca. 1.65 Ga granitic intrusions. Core ages ca. 1.5 Ga are likely due to a mixing age of two different age domains during analyses. Confirmed sedimentation at 1.48-1.45 Ga and documented mid-crustal regional metamorphism in northern New Mexico ca. 1.44-1.40 are likely associated with a Mesoproterozoic orogenic event.
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Solar research is primarily conducted in regions with consistent sunlight, severely limiting research opportunities in many areas. Unfortunately, the unreliable weather in Lewisburg, PA, can prove difficult for such testing to be conducted. As such, a solar simulator was developed for educational purposes for the Mechanical Engineering department at Bucknell University. The objective of this work was to first develop a geometric model to evaluate a one sun solar simulator. This was intended to provide a simplified model that could be used without the necessity of expensive software. This model was originally intended to be validated experimentally, but instead was done using a proven ray tracing program, TracePro. Analyses with the geometrical model and TracePro demonstrated the influence the geometrical properties had results, specifically the reflector (aperture) diameter and the rim angle. Subsequently, the two were approaches were consistent with one another for aperture diameters 0.5 m and larger, and for rim angles larger than 45°. The constructed prototype, that is currently untested, was designed from information provided by the geometric model, includes a metal halide lamp with a 9.5 mm arc diameter and parabolic reflector with an aperture diameter of 0.631 meters. The maximum angular divergence from the geometrical model was predicted to be 30 mRadians. The average angular divergence in TraceProof the system was 19.5 mRadians, compared to the sun’s divergence of 9.2 mRadians. Flux mapping in TracePro showed an intensity of 1000 W/m2 over the target plane located 40 meters from the lamp. The error between spectrum of the metal halide lamp and the solar spectrum was 10.9%, which was found by comparing their respective Plank radiation distributions. The project did not satisfy the original goal of matching the angular divergence of sunlight, although the system could still to be used for optical testing. The geometric model indicated performance in this area could be improved by increasing the diameter of the reflector, as well as decreasing the source diameter. Although ray tracing software provides more information to analyze the simulator system, the geometrical model is adequate to provide enough information to design a system.
Resumo:
AIMS: To compare morphometric parameters and diagnostic performance of the new Stratus Optical Coherence Tomograph (OCT) Disc mode and the Heidelberg Retina Tomograph (HRT); to evaluate OCT's accuracy in determining optic nerve head (ONH) borders. METHODS: Controls and patients with ocular hypertension, glaucoma-like discs, and glaucoma were imaged with OCT Disc mode, HRT II, and colour disc photography (DISC-PHOT). In a separate session, automatically depicted ONH shape and size in OCT were compared with DISC-PHOT, and disc borders adjusted manually where required. In a masked fashion, all print-outs and photographs were studied and discs classified as normal, borderline, and abnormal. The Cohen kappa method was then applied to test for agreement of classification. Bland-Altman analysis was used for comparison of disc measures. RESULTS: In all, 49 eyes were evaluated. Automated disc margin recognition failed in 53%. Misplaced margin points were more frequently found in myopic eyes, but only 31/187 were located in an area of peripapillary atrophy. Agreement of OCT with photography-based diagnosis was excellent in normally looking ONHs, but moderate in discs with large cups, where HRT performed better. OCT values were consistently larger than HRT values for disc and cup area. Compared with HRT, small rim areas and volumes tended to be minimized by OCT, and larger ones to be magnified. CONCLUSIONS: Stratus OCT Disc protocol performed overall well in differentiating between normal and glaucomatous ONHs. However, failure of disc border recognition was frequently observed, making manual correction necessary. ONH measures cannot be directly compared between HRT and OCT.
Resumo:
Iatrogenic atrial septal defects are described in 2 patients. They occurred after implantation of Amplatzer occluders to close a patent foramen ovale. While device erosions to the extra-atrial space have been described, erosion induced atrial septal defects are a new medical entity. They may be fairly common in the situation of an atrial septal aneurysm whipping the rim of the device incessantly. They are clinically silent and benign and require echocardiography for detection. A second device solved the problem in the cases described.
Resumo:
BACKGROUND: Recent advances in the understanding of the anatomy and function of the acetabular labrum suggest that it is important for normal joint function. We found no available data regarding whether labral refixation after treatment of femoro-acetabular impingement affects the clinical and radiographic results. METHODS: We retrospectively reviewed the clinical and radiographic results of fifty-two patients (sixty hips) with femoro-acetabular impingement who underwent arthrotomy and surgical dislocation of the hip to allow trimming of the acetabular rim and femoral osteochondroplasty. In the first twenty-five hips, the torn labrum was resected (Group 1); in the next thirty-five hips, the intact portion of the labrum was reattached to the acetabular rim (Group 2). At one and two years postoperatively, the Merle d'Aubigné clinical score and the Tönnis arthrosis classification system were used to compare the two groups. RESULTS: At one year postoperatively, both groups showed a significant improvement in their clinical scores (mainly pain reduction) compared with their preoperative values (p = 0.0003 for Group 1 and p < 0.0001 for Group 2). At two years postoperatively, 28% of the hips in Group 1 (labral resection) had an excellent result, 48% had a good result, 20% had a moderate result, and 4% had a poor result. In contrast, in Group 2 (labral reattachment), 80% of the hips had an excellent result, 14% had a good result, and 6% had a moderate result. Comparison of the clinical scores between the two groups revealed significantly better outcomes for Group 2 at one year (p = 0.0001) and at two years (p = 0.01). Radiographic signs of osteoarthritis were significantly more prevalent in Group 1 than in Group 2 at one year (p = 0.02) and at two years (p = 0.009). CONCLUSIONS: Patients treated with labral refixation recovered earlier and had superior clinical and radiographic results when compared with patients who had undergone resection of a torn labrum. Although the results must be considered preliminary, we now recommend refixation of the intact portion of the labrum after trimming of the acetabular rim during surgical treatment of femoro-acetabular impingement.
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This paper presents a case of a 28-year-old male with a seizure episode and a 4-year history of intermittent tinnitus on the left ear. On computed tomography and magnetic resonance imaging, a density with rim enhancement was found at the temporal lobe, associated with mastoid tegmen destruction and middle ear mass, indicating cholesteatoma with complicating brain abscess. Evacuation of the brain abscess was performed with a combined otolaryngologic and neurosurgical procedures (canal wall-down mastoidectomy and temporal craniotomy). The pathology turned out to be infestation with Echinococcus granulosus.
Resumo:
Chronic irritation of the iliopsoas tendon is a rare cause of persistent pain after total joint replacement of the hip. In the majority of cases, pain results from a mechanical conflict between the iliopsoas tendon and the anterior edge of the acetabular cup after total hip arthroplasty. Pain can be reproduced by active flexion of the hip and by active raising of the straightened leg. In addition, painful leg raising against resistance and passive hyperextension are suggestive of an irritation of the iliopsoas tendon. Symptoms evolve from a mechanical irritation of the iliopsoas tendon and an oversized or retroverted acetabular cup, screws penetrating into the inner aspect of the ilium, or from bone cement protruding beyond the anterior acetabular rim. The diagnosis may be assumed on conventional radiographs and confirmed by CT scans. Fifteen patients with psoas irritation after total hip replacement are reported on. Eleven patients were treated surgically. The acetabular cup was revised and reoriented with more anteversion in six patients, isolated screws penetrating into the tendon were cut and leveled in three patients, and prominent bone cement in conflict with the tendon was resected once. A partial release of the iliopsoas tendon only was performed in another patient. Follow-up examination (range: 11-89 months) revealed that nine patients were free of pain and two patient had mild residual complaints. Psoas irritation in combination with total hip replacement can be prevented by a correct surgical technique, especially with proper selection of the cup size and insertion of the acetabular cup avoiding a rim position exceeding the level of the anterior acetabular rim.
Resumo:
We developed an object-oriented cross-platform program to perform three-dimensional (3D) analysis of hip joint morphology using two-dimensional (2D) anteroposterior (AP) pelvic radiographs. Landmarks extracted from 2D AP pelvic radiographs and optionally an additional lateral pelvic X-ray were combined with a cone beam projection model to reconstruct 3D hip joints. Since individual pelvic orientation can vary considerably, a method for standardizing pelvic orientation was implemented to determine the absolute tilt/rotation. The evaluation of anatomically morphologic differences was achieved by reconstructing the projected acetabular rim and the measured hip parameters as if obtained in a standardized neutral orientation. The program had been successfully used to interactively objectify acetabular version in hips with femoro-acetabular impingement or developmental dysplasia. Hip(2)Norm is written in object-oriented programming language C++ using cross-platform software Qt (TrollTech, Oslo, Norway) for graphical user interface (GUI) and is transportable to any platform.
Resumo:
PURPOSE: The purpose of this study was to examine whether arthroscopic adhesiolysis can relieve symptoms of patients with persistent pain after open surgical hip dislocation for femoroacetabular impingement syndrome without osseous or cartilaginous alterations. METHODS: This study comprised 16 consecutive patients (6 men and 10 women; mean age, 33.5 years [range, 19 to 60 years]) with persistent pain without osseous or cartilaginous alterations after surgical hip dislocation for the treatment of femoroacetabular impingement. At index surgery, all patients had osteochondroplasty of the head-neck junction and resection of the acetabular rim with reattachment of the labrum in 9 cases. All patients had preoperative magnetic resonance imaging-arthrogram and were treated with arthroscopy of the hip. RESULTS: At arthroscopy, all reattached labra were stable. In the cases without preservation of the labrum at the index operation, the joint capsule was attached at the level of the acetabular rim and synovitis was noticed. All patients had adhesions between the neck of the femur and joint capsule or between the labrum and capsule. In 3 patients the arthroscopic procedure was technically limited by massive thickening of the capsule. Overall, 81% of patients (13/16) showed less pain or were pain-free. The Merle d'Aubigné score improved from 13 points preoperatively to 16 points at the last follow-up. CONCLUSIONS: Persistent pain after surgical dislocation of the hip without evidence of cartilaginous and osseous alterations could result from intra-articular adhesions. Hip arthroscopy after previous surgery can be demanding because of scarring. If the adhesions can be released, good results can be achieved. LEVEL OF EVIDENCE: Level IV, therapeutic case series.
Resumo:
BACKGROUND: Recent advances in the understanding of the anatomy and function of the acetabular labrum suggest that it is important for normal joint function. We found no available data regarding whether labral refixation after treatment of femoro-acetabular impingement affects the clinical and radiographic results. METHODS: We retrospectively reviewed the clinical and radiographic results of fifty-two patients (sixty hips) with femoro-acetabular impingement who underwent arthrotomy and surgical dislocation of the hip to allow trimming of the acetabular rim and femoral osteochondroplasty. In the first twenty-five hips, the torn labrum was resected (Group 1); in the next thirty-five hips, the intact portion of the labrum was reattached to the acetabular rim (Group 2). At one and two years postoperatively, the Merle d'Aubigné clinical score and the Tönnis arthrosis classification system were used to compare the two groups. RESULTS: At one year postoperatively, both groups showed a significant improvement in their clinical scores (mainly pain reduction) compared with their preoperative values (p = 0.0003 for Group 1 and p < 0.0001 for Group 2). At two years postoperatively, 28% of the hips in Group 1 (labral resection) had an excellent result, 48% had a good result, 20% had a moderate result, and 4% had a poor result. In contrast, in Group 2 (labral reattachment), 80% of the hips had an excellent result, 14% had a good result, and 6% had a moderate result. Comparison of the clinical scores between the two groups revealed significantly better outcomes for Group 2 at one year (p = 0.0001) and at two years (p = 0.01). Radiographic signs of osteoarthritis were significantly more prevalent in Group 1 than in Group 2 at one year (p = 0.02) and at two years (p = 0.009). CONCLUSIONS: Patients treated with labral refixation recovered earlier and had superior clinical and radiographic results when compared with patients who had undergone resection of a torn labrum. Although the results must be considered preliminary, we now recommend refixation of the intact portion of the labrum after trimming of the acetabular rim during surgical treatment of femoro-acetabular impingement.
Resumo:
Sibling and parente-offspring conflicts arise mainly over the amount and distribution of parental care, especially food. In altricial bird species where the young depend on parents for obtaining food, parents may control sibling competition by the choice of their respective provisioning locations. In great tits, the parents use fixed provisioning positions on the nest rim that are determined early in the breeding cycle and maintained until. edging. The two parents may choose positions that are close to each other, or far apart, and thereby increase or relax the pressure for optimal feeding positioning among nestlings. As an inspiration to this study we previously found that the two parents provide food from closer positions if the nest is infested by ectoparasites. Here, we tested the hypothesis that the parental choice of relative provisioning locations could be strategically used to control nestling competition. We forced parents to feed from either one or two provisioning locations and assessed the induced change in nestling movement, weight gain, and food distribution among siblings. We show that the angular distance between male and female locations influences the level of behavioural competition and affects nestling weight gain and food distribution. It is the first evidence for hole-nesting birds, where it was assumed that the nestling closest to the entrance hole was fed first, that the apparent choice of feeding positions by parents could be a way of controlling sibling competition and thereby also taking partial control over the outcome of parente-offspring conflict. (c) 2007 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Resumo:
OBJECTIVE: The aim of this study was to determine the presence and absence of acupuncture ear points in healthy neonates. DESIGN: This was a prospective observational study performed at a university teaching hospital. Subjects: The subjects were healthy neonates. We compared male and female neonates, right and left lobe, term and preterm deliveries, and cesarean sections versus vaginal deliveries. Examinations took place on the fifth day after delivery and were performed by a neuronal pen (SVESA 1070, SVESA GmbH, Munich, Germany). An integrated optical signal detected the ear points that were assigned to the Chinese ear map. MAIN OUTCOME MEASURES: This study looked at the presence and absence of acupuncture ear points in neonates. RESULTS: There were 27 male neonates and 23 female neonates. In 66% of neonates, no points at all were found. We detected 0-4 points on the right lobe and 0-2 points on the left lobe. The psychovegetative rim was the most common point in 26% of all children. No psychic points were detected. No significant differences were found between right and left ear lobes, male and female neonates, or term and preterm deliveries with respect to numbers of points or access of points. Moreover, there were no differences among modes of delivery. CONCLUSIONS: Some ear points in healthy neonates are detectable and not dependent on side of the ear lobe. Females had significantly more acupuncture points. There was an extremely significant difference in the group with 2 active earpoints between cesarean and vaginally delivered neonates. The most important point was the psychovegetative rim and the absence of psychic points in favor of the organ points. Possibly, ear points in neonates could be used for diagnostic and therapeutic options in neonates in the future.
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Shear-wave splitting can be a useful technique for determining crustal stress fields in volcanic settings and temporal variations associated with activity. Splitting parameters were determined for a subset of local earthquakes recorded from 2000-2010 at Yellowstone. Analysis was automated using an unsupervised cluster analysis technique to determine optimum splitting parameters from 270 analysis windows for each event. Six stations clearly exhibit preferential fast polarization values sub-orthogonal to the direction of minimum horizontal compression. Yellowstone deformation results in a local crustal stress field differing from the regional field dominated by NE-SW extension, and fast directions reflect this difference rotating around the caldera maintaining perpendicularity to the rim. One station exhibits temporal variations concordant with identified periods of caldera subsidence and uplift. From splitting measurements, we calculated a crustal anisotropy of ~17-23% and crack density ~0.12-0.17 possibly resulting from stress-aligned fluid filled microcracks in the upper crust and an active hydrothermal system.
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Although current concepts of anterior femoroacetabular impingement predict damage in the labrum and the cartilage, the actual joint damage has not been verified by computer simulation. We retrospectively compared the intraoperative locations of labral and cartilage damage of 40 hips during surgical dislocation for cam or pincer type femoroacetabular impingement (Group I) with the locations of femoroacetabular impingement in 15 additional hips using computer simulation (Group II). We found no difference between the mean locations of the chondrolabral damage of Group I and the computed impingement zone of Group II. The standard deviation was larger for measures of articular damage from Group I in comparison to the computed values of Group II. The most severe hip damage occurred at the zone of highest probability of femoroacetabular impact, typically in the anterosuperior quadrant of the acetabulum for both cam and pincer type femoroacetabular impingements. However, the extent of joint damage along the acetabular rim was larger intraoperatively than that observed on the images of the 3-D joint simulations. We concluded femoroacetabular impingement mechanism contributes to early osteoarthritis including labral lesions. LEVEL OF EVIDENCE: Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.