364 research outputs found
Study of Stretched Configuration High-Spin States in the Nickel Region with the (d,α) Reaction
This work was supported by the National Science Foundation Grant NSF PHY 78-22774 A02 & A03 and by Indiana Universit
Shrinkage of the distal renal artery 1 year after stent placement as evidenced with serial intravascular ultrasound
The objective of this study was to determine the quantitative
intravascular ultrasound (IVUS) and angiographic changes that occur during
1 year follow-up after renal artery stent placement, given that restenosis
continues to be a limitation of renal artery stent placement. 38
consecutive patients with symptomatic renal artery stenosis treated with
Palmaz stent placement were studied prospectively. IVUS and angiography
were performed at the time of stent placement and at 1 year follow-up. At
follow-up, angiographic restenosis was seen in 14% of patients. The lumen
area in the stent, seen with IVUS, was significantly decreased from
24+/-5.6 mm(2) to 17+/-5.6 mm(2) (p<0.001) solely due to plaque
accumulation. The distal main renal artery showed a significant decrease
in lumen area owing to a significant vessel area decrease from 39+/-14.0
mm(2) to 29+/-9.3 mm(2) (p<0.001) without plaque accumulation.
Angiographic analysis confirmed this reduction in luminal diameter and
showed that the distal renal artery diameter at follow-up was
significantly smaller than before stent placement (86+/-23.0% vs
104+/-23.9% of the contralateral renal artery diameter; p=0.003). Besides
plaque accumulation in the stent, unexplained shrinkage of the distal main
renal artery was evidenced with IVUS and angiography 1 year following
stent placement
Intravascular ultrasound evidence for coarctation causing symptomatic renal artery stenosis
BACKGROUND: A recent study of human cadaveric renal arteries revealed that
renal artery narrowing could be due not only to atherosclerotic plaque
compensated for by adaptive remodeling, but also to hitherto undescribed
focal narrowing of an otherwise normal renal arterial wall (ie,
coarctation). The present study investigated whether vessel coarctation
could be identified in patients with symptomatic renal artery stenosis
(RAS). METHODS AND RESULTS: Consecutive symptomatic patients with
angiographically proven atherosclerotic RAS who were referred for stent
placement were studied by 30-MHz intravascular ultrasound before
intervention (n=18) or after predilatation (n=18). Analysis included
assessment of the media-bounded area and plaque area (PLA) at the most
stenotic site and at a distal reference site (most distal cross-section in
the main renal artery with normal appearance). Coarctation was considered
present whenever the target/reference media-bounded area was </=85%.
Before intervention, coarctation was observed in 9 of 18 patients and
adaptive remodeling in 9 of 18 patients. Coarctation lesions had a
significantly smaller PLA than adaptive remodeled lesions (P=0.001).
Similarly, despite predilatation, coarctation was seen in 8 of 18 patients
who had significantly smaller PLAs (P=0. 008) when compared with those
patients who had adaptive remodeled lesions. No differences in severity of
RAS or angiographic or clinical parameters were observed. CONCLUSIONS:
Low-plaque coarctation may cause a considerable proportion of symptomatic
RAS, which is angiographically and clinically indistinguishable from
plaque-rich RAS
Face-to-face vs telephone pre-colonoscopy consultation in colorectal cancer screening; A randomised trial
Background: A pre-colonoscopy consultation in colorectal cancer (CRC) screening is necessary to assess a screenees general health status and to explain benefits and risks of screening. The first option allows for personal attention, whereas a telephone consultation does not require travelling. We hypothesised that a telephone consultation would lead to higher response and participation in CRC screening compared with a face-to-face consultation. Methods:A total of 6600 persons (50-75 years) were 1: 1 randomised for primary colonoscopy screening with a pre-colonoscopy consultation either face-to-face or by telephone. In both arms, we counted the number of invitees who attended a pre-colonoscopy consultation (response) and the number of those who subsequently attended colonoscopy (participation), relative to the number invited for screening. A questionnaire regarding satisfaction with the consultation and expected burden of the colonoscopy (scored on five-point rating scales) was sent to invitees. Besides, a questionnaire to assess the perceived burden of colonoscopy was sent to participants, 14 days after the procedure.Results:In all, 3302 invitees were allocated to the telephone group and 3298 to the face-to-face group, of which 794 (24%) attended a telephone consultation and 822 (25%) a face-to-face consultation (P=0.41). Subsequently, 674 (20%) participants in the telephone group and 752 (23%) in the face-to-face group attended colonoscopy (P=0.018). Invitees and responders in the telephone group expected the bowel preparation to be more painful than those in the face-to-face group while perceived burden scores for the full screening procedure were comparable. More subjects in the face-to-face group than in the telephone group were satisfied by the consultation in general: (99.8% vs 98.5%, P=0.014).Conclusion:Using a telephone rather than a face-to-face consultation in a population-based CRC colonoscopy screening progr
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Validation of OMI Tropospheric NO2 Observations During INTEX-B and Application to Constrain NOx Emissions Over the Eastern United States and Mexico
We compare tropospheric NO2 column measurements from the Ozone Monitoring Instrument (OMI) aboard the EOS Aura satellite with coincident in situ aircraft measurements on vertical spirals over the southern United States, Mexico, and the Gulf of Mexico during the INTEX-B campaign in March 2006. Good correlation with no significant bias (r2=0.67, slope=0.99±0.17, n=12) is found for the ensemble of comparisons when the aircraft could spiral sufficiently low to sample most of the NO2 column. Urban spirals where large extrapolations were needed below the aircraft floor (1000 ft) showed poorer agreement. We use the OMI observations together with a global chemical transport model (GEOS-Chem) to estimate emissions of nitrogen oxides over the eastern United States and Mexico in March 2006. Comparison to EPA's National Emissions Inventory 1999 (NEI99) calls for a decrease in power plant emissions and an increase in on-road vehicle emissions relative to that inventory. The rise in vehicular emissions is offsetting the reduction in power plant and industry emissions. These findings are consistent with independent assessments. Our OMI-derived emission estimates for Mexico are higher by a factor of 2.0±0.5 than bottom-up emissions, similar to a comparison between the recently released Mexican NEI99 inventory and the bottom-up showing that the Mexican NEI99 inventory is 1.6–1.8× higher.Earth and Planetary SciencesEngineering and Applied Science
Stent placement for renal arterial stenosis: where do we stand? A meta-analysis
PURPOSE: To perform a meta-analysis of renal arterial stent placement in
comparison with renal percutaneous transluminal angioplasty (PTA) in
patients with renal arterial stenosis. MATERIALS AND METHODS: Studies
dealing with renal arterial stent placement (14 articles; 678 patients)
and renal PTA (10 articles; 644 patients) published up to August 1998 were
selected. A random-effects model was used to pool the data. RESULTS: Renal
arterial stent placement proved highly successful, with an initial
adequate performance in 98% and major complications in 11%. The overall
cure rate for hypertension was 20%, whereas hypertension was improved in
49%. Renal function improved in 30% and stabilized in 38% of patients. The
restenosis rate at follow-up of 6-29 months was 17%. Stent placement had a
higher technical success rate and a lower restenosis rate than did renal
PTA (98% vs 77% and 17% vs 26%, respectively; P <.001). The complication
rate was not different between the two treatments. The cure rate for
hypertension was higher and the improvement rate for renal function was
lower after stent placement than after renal PTA (20% vs 10% and 30% vs
38%, respectively; P <.001). CONCLUSION: Renal arterial stent placement is
technically superior and clinically comparable to renal PTA alone
Graviton Resonances in E+ E- -> MU+ MU- at Linear Colliders with Beamstrahlung and ISR Effects
Electromagnetic radiation emitted by the colliding beams is expected to play
an important role at the next generation of high energy e^+ e^- linear
collider(s). Focusing on the simplest process e+e- -> mu+ mu-, we show that
radiative effects like initial state radiation (ISR) and beamstrahlung can lead
to greatly-enhanced signals for resonant graviton modes of the Randall-Sundrum
model.Comment: 20 pages Latex, 7 eps figure
Burden of waiting for surveillance CT colonography in patients with screen-detected 6–9 mm polyps
Purpose: We assessed the burden of waiting for surveillance CT colonography (CTC) performed in patients having 6–9 mm colorectal polyps on primary screening CTC. Additionally, we compared the burden of primary and surveillance CTC. Materials and methods: In an invitational population-based CTC screening trial, 101 persons were diagnosed with <3 polyps 6–9 mm, for which surveillance CTC after 3 years was advised. Validated questionnaires regarding expected and perceived burden (5-point Likert scales) were completed before and after index and surveillance CTC, also including items on burden of waiting for surveillance CTC. McNemar’s test was used for comparison after dichotomization. Results: Seventy-eight (77 %) of 101 invitees underwent surveillance CTC, of which 66 (85 %) completed the expected and 62 (79 %) the perceived burden questionnaire. The majority of participants (73 %) reported the experience of waiting for surveillance CTC as ‘never’ or ‘only sometimes’ burdensome. There was almost no difference in expected and perceived burden between surveillance and index CTC. Waiting for the results after the procedure was significantly more burdensome for surveillance CTC than for index CTC (23 vs. 8 %; p = 0.012). Conclusion: Waiting for surveillance CTC after primary CTC screening caused little or no burden for surveillance participants. In general, the burden of surveillance and index CTC were comparable. Key points: • Waiting for surveillance CTC withi
Computer tomography colonography participation and yield in patients under surveillance for 6-9 mm polyps in a population-based screening trial
Purpose: Surveillance CT colonography (CTC) is a viable option for 6-9 mm polyps at CTC screening for colorectal cancer. We established participation and diagnostic yield of surveillance and determined overall yield of CTC screening. Material and methods: In an invitational CTC screening trial 82 of 982 participants harboured 6-9 mm polyps as the largest lesion(s) for which surveillance CTC was advised. Only participants with one or more lesion(s) ≥6 mm at surveillance CTC were offered colonoscopy (OC); 13 had undergone preliminary OC. The surveillance CTC yield was defined as the number of participants with advanced neoplasia in the 82 surveillance participants, and was added to the primary screening yield. Results: Sixty-five of 82 participants were eligible for surveillance CTC of which 56 (86.2 %) participated. Advanced neoplasia was diagnosed in 15/56 participants (26.8 %) and 9/13 (69.2 %) with preliminary OC. Total surveillance yield was 24/82 (29.3 %). No carcinomas were detected. Adding surveillance results to initial screening CTC yield significantly increased the advanced neoplasia yield per 100 CTC participants (6.1 to 8.6; p < 0.001) and per 100 invitees (2.1 to 2.9; p < 0.001). Conclusion: Surveillance CTC for 6-9 mm polyps has a substantial yield of advanced adenomas and significantly increased the CTC yield in population screening. Key Points: • The participation rate in surveillance CT colonography (CTC) is 86 %. • Advanced adenoma prevalence in a 6-9 mm CTC surveillance population is high. • Surveillance CTC significantly increases the yield of population screening by CTC. • Surveillance CTC for 6-9 mm polyps is a safe strategy. • Sur
Study protocol: Population screening for colorectal cancer by colonoscopy or CT colonography: A randomized controlled trial
Background: Colorectal cancer (CRC) is the second most prevalent type of cancer in Europe. Early detection and removal of CRC or its precursor lesions by population screening can reduce mortality. Colonoscopy and computed tomography colonography (CT colonography) are highly accurate exams and screening options that examine the entire colon. The success of screening depends on the participation rate. We designed a randomized trial to compare the uptake, yield and costs of direct colonoscopy population screening, using either a telephone consultation or a consultation at the outpatient clinic, versus CT colonography first, with colonoscopy in CT colonography positives.Methods and design: 7,500 persons between 50 and 75 years will be randomly selected from the electronic database of the municipal administration registration and will receive an invitation to participate in either CT colonography (2,500 persons) or colonoscopy (5,000 persons) screening. Those invited for colonoscopy screening will be randomized to a prior consultation either by telephone or a visit at the outpatient clinic. All CT colonography invitees will have a prior consultation by telephone. Invitees are instructed to consult their general practitioner and not to participate in screening if they have symptoms suggestive for CRC. After provid
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