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Purpose: To evaluate the accuracy and technical success of positioning a radiofrequency ablation (RFA) electrode in osteoid osteomas by use of a new real-time needle guidance technology combining cone-beam computed tomography (CT) and fluoroscopy.Materials and Methods: Percutaneous RFA of osteoid osteomas was performed in five patients (median age 18 years), under general anesthesia, with the use of cone-beam CT and fluoroscopic guidance for electrode positioning. The outcome parameters were technical success, meaning correct needle placement in the nidus; accuracy defined as the deviation (in mm) from the center of the nidus; and clinical outcome at follow-up.Results: In all five cases, positioning was possible within 3 mm of the determined target location (median nidus size 6.8 mm; range 5-10.2 mm). All procedures were technically successful. All patients were free of pain at clinical follow-up. No complications were observed.Conclusion: Real-time fluoroscopy needle guidance based on cone-beam CT is a useful tool to accurately position radiofrequency needles for minimally invasive treatment of osteoid osteomas. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the technical performance and immediate procedure outcome of a new balloon catheter in the treatment of calcified lesions in infrainguinal arterial disease. Seventy-five patients with infrainguinal arterial disease were prospectively entered into the registry. The catheter (ReeKross Clearstream, Ireland) is a 5- to 6-Fr balloon catheter with a rigid shaft intended for enhanced pushability. Only technical procedural outcome was recorded. Treated calcified lesions (range: 5-30 cm), assessed angiographically, were located in the superficial femoral, popliteal, and crural arteries. In 67 patients the lesion was an occlusion. Guidewire passage occurred subintimally in 68 patients. In 24 patients a standard balloon catheter was chosen as first treatment catheter: 5 failed to cross the lesion, 8 balloons ruptured, and in 11 patients there was an inadequate dilatation result. In only one of the five patients did subsequent use of the ReeKross catheter also fail in lesion crossing. The ReeKross was successful as secondary catheter in the other 23 cases. In 50 patients the ReeKross was used as primary catheter. In total the ReeKross crossed the lesions in 74 patients. After passage and dilatation with this catheter in 73 patients (1 failed true-lumen reentry), 19 had >30% residual lesions, of which 11 were not treated and 8 were successfully stented. No ReeKross balloons ruptured. We conclude that in the treatment of difficult calcified lesions in arterial stenotic or occlusive disease, the choice of a high-pushability angioplasty catheter, with more calcification-resistant balloon characteristics, like the ReeKross, warrants consideration. [ABSTRACT FROM AUTHOR]

Background: In deep inferior epigastric perforator (DIEP) flap breast reconstructions, a free tissue flap from the abdomen is shaped into a breast and transferred to the thorax. Survival of this free flap relies on minuscule blood vessels, so-called perforators, providing blood supply to this newly molded breast. Preoperative mapping of these randomly distributed blood vessels is essential to avoid complications. The purpose of this study was to investigate whether the preoperative projection of a virtual three-dimensional plan based on computed tomographic angiography onto the abdomen leads to more correctly identified perforator locations and less operative time spent on dissecting the free flap compared to the commonly used Doppler ultrasound planning method., Methods: The authors conducted a randomized, open, single-center, superiority trial in patients undergoing DIEP flap breast reconstruction with 1-week follow-up. Randomized participants were 60 adults (projection method, n = 33; Doppler method, n = 27) undergoing DIEP flap breast reconstruction without lymph node transfer., Results: Sixty patients provided 69 DIEP flaps for analysis. The projection method is capable preoperatively of displaying significantly more perforators compared to the Doppler method (61.7 ± 7.3 percent versus 41.2 ± 8.2 percent, respectively; p = 0.020)). During the procedure, flap harvest time is decreased by 19 minutes (136 ± 7 minutes versus 155 ± 7 minutes; p = 0.012). Complications were comparable across both groups., Conclusion: Not only can more perforators be identified intraoperatively using the projection method compared with Doppler ultrasound, there is also a significant time reduction in harvesting the DIEP flap., Clinical Question/level of Evidence: Therapeutic, II.

Iron-containing metallic implants are shown herein to mediate hydrolysis of glycosidic linkages. Using glucuronide prodrugs for broad-spectrum fluoroquinolone antibacterial agents, we capitalize on this behaviour and perform localized synthesis of antimicrobials which affords a significant zone of inhibition of bacterial growth around the metallic material.

Background: Recurrent hemarthrosis is a late complication in up to 1.6% of patients following total knee arthroplasty (TKA). In the absence of intrinsic coagulopathy, one etiology is bleeding of hypertrophic vascular synovium. The aim of this study is to evaluate the clinical outcome of patients referred to our center for angiographic embolization of geniculate arteries for recurrent hemarthrosis following TKA., Methods: We retrospectively studied a cohort of patients who were referred for geniculate artery embolization following TKA between August 2011 and September 2016., Results: A total of 24 embolization procedures were performed on 14 patients. Seven (50%) of these 14 patients underwent one embolization procedure. Due to symptom recurrence, 4 patients underwent a repeated procedure and 3 patients a third procedure. All embolization procedures were technically successful at the time of the procedure. Two patients reported an inguinal hematoma that healed without further treatment. At follow-up of mean 26.8 months, clinical success was achieved in 12 of the 14 patients (86%)., Conclusion: Embolization of the geniculate arteries in our study was a safe and effective treatment of recurrent spontaneous hemarthrosis following TKA. Although we have performed a substantial number of reinterventions, results of this study show that this procedure can be safely repeated without adverse events. Our results indicate that embolization could possibly be the treatment of choice when conservative measures fail and can be repeated in the event of recurrent or persistent symptoms., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: Implantation of pre-endothelialized stents could enhance cellular recovery of a damaged vessel wall provided attached cells remain viable, functional and are present in sufficient numbers after deployment. The purpose of this study was to evaluate the feasibility of grooved stainless steel (SS) stents as a primary endothelial cell (EC) carrier with potentially enhanced EC protection upon stent deployment., Materials and Methods: Attachment and behavior of enzymatically harvested human adult venous ECs seeded onto gelatin-coated vascular stents were evaluated in an in vitro setting. Smooth and grooved SS stents and smooth nitinol stents were studied., Results: All cells expressed EC markers vWF and CD31. Using rotational seeding for a period of 16-24 h, ECs attached firmly to the stents with sufficient coverage to form a confluent EC monolayer. The grooved SS wire design was found to enable attachment of three times the number of cells compared to smooth wires. This also resulted in an increased number of cells remaining on the stent after deployment and after pulsatile flow of 180 ml/min for 24 h, which did not result in additional EC detachment., Conclusions: The grooved stent provides a potential percutaneous means to deliver sufficient numbers of viable and functional cells to a vessel segment during vascular intervention. The grooves were found to offer a favorable surface for EC attachment and protection during stent deployment in an in vitro setting.

Background: Determining the ideal volume of the harvested flap to achieve symmetry in deep inferior epigastric artery perforator (DIEP) flap breast reconstructions is complex. With preoperative imaging techniques such as 3D stereophotogrammetry and computed tomography angiography (CTA) available nowadays, we can combine information to preoperatively plan the optimal flap volume to be harvested. In this proof-of-concept, we investigated whether projection of a virtual flap planning onto the patient's abdomen using a projection method could result in harvesting the correct flap volume., Methods: In six patients (n = 9 breasts), 3D stereophotogrammetry and CTA data were combined from which a virtual flap planning was created comprising perforator locations, blood vessel trajectory and flap size. All projected perforators were verified with Doppler ultrasound. Intraoperative flap measurements were collected to validate the determined flap delineation volume., Results: The measured breast volume using 3D stereophotogrammetry was 578 ± 127 cc; on CTA images, 527 ± 106 cc flap volumes were planned. The nine harvested flaps weighed 533 ± 109 g resulting in a planned versus harvested flap mean difference of 5 ± 27 g (flap density 1.0 g/ml). In 41 out of 42 projected perforator locations, a Doppler signal was audible., Conclusion: This proof-of-concept shows in small numbers that flap volumes can be included into a virtual DIEP flap planning, and transferring the virtual planning to the patient through a projection method results in harvesting approximately the same volume during surgery. In our opinion, this innovative approach is the first step in consequently achieving symmetric breast volumes in DIEP flap breast reconstructions., (Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

Purpose: To assess whether laser guidance can reduce fluoroscopy and procedure time of cone-beam computed tomography (CBCT)-guided radiofrequency (RF) ablations of osteoid osteoma compared to freehand CBCT guidance., Materials and Methods: 32 RF ablations were retrospectively analyzed, 17 laser-guided and 15 procedures using the freehand technique. Subgroup selection of 18 ablations in the hip-pelvic region with a similar degree of difficulty was used for a direct comparison. Data are presented as median (ranges)., Results: Comparison of all 32 ablations resulted in fluoroscopy times of 365 s (193-878 s) for freehand and 186 s (75-587 s) for laser-guided procedures (p = 0.004). Corresponding procedure times were 56 min (35-97 min) and 52 min (30-85 min) (p = 0.355). The subgroup showed comparable target sizes, needle path lengths, and number of scans between groups. Fluoroscopy times were lower for laser-guided procedures, 215 s (75-413 s), compared to 384 s (193-878 s) for freehand (p = 0.012). Procedure times were comparable between groups, 51 min (30-72 min) for laser guidance and 58 min (35-79 min) for freehand (p = 0.172)., Conclusion: Adding laser guidance to CBCT-guided osteoid osteoma RF ablations significantly reduced fluoroscopy time without increasing procedure time., Level of Evidence: Level 4, case series.

Purpose: When using laser guidance for cone-beam computed tomography (CBCT)-guided needle interventions, planned needle paths are visualized to the operator without the need to switch between entry- and progress-view during needle placement. The current study assesses the effect of laser guidance during CBCT-guided biopsies on fluoroscopy and procedure times., Materials and Methods: Prospective data from 15 CBCT-guided biopsies of 8-65 mm thoracic and abdominal lesions assisted by a ceiling-mounted laser guidance technique were compared to retrospective data of 36 performed CBCT-guided biopsies of lesions >20 mm using the freehand technique. Fluoroscopy time, procedure time, and number of CBCT-scans were recorded. All data are presented as median (ranges)., Results: For biopsies using the freehand technique, more fluoroscopy time was necessary to guide the needle onto the target, 165 s (83-333 s) compared to 87 s (44-190 s) for laser guidance (p < 0.001). Procedure times were shorter for freehand-guided biopsies, 24 min versus 30 min for laser guidance (p < 0.001)., Conclusion: The use of laser guidance during CBCT-guided biopsies significantly reduces fluoroscopy time.

Purpose: We assessed whether image registration of cone-beam computed tomography (CT) (CBCT) and contrast-enhanced CT (CE-CT) images indicating the locations of the adrenal veins can aid in increasing the success rate of first-attempts adrenal vein sampling (AVS) and therefore decreasing patient radiation dose., Materials and Methods: CBCT scans were acquired in the interventional suite (Philips Allura Xper FD20) and rigidly registered to the vertebra in previously acquired CE-CT. Adrenal vein locations were marked on the CT image and superimposed with live fluoroscopy and digital-subtraction angiography (DSA) to guide the AVS. Seventeen first attempts at AVS were performed with image registration and retrospectively compared with 15 first attempts without image registration performed earlier by the same 2 interventional radiologists. First-attempt AVS was considered successful when both adrenal vein samples showed representative cortisol levels. Sampling time, dose-area product (DAP), number of DSA runs, fluoroscopy time, and skin dose were recorded., Results: Without image registration, the first attempt at sampling was successful in 8 of 15 procedures indicating a success rate of 53.3%. This increased to 76.5% (13 of 17) by adding CBCT and CE-CT image registration to AVS procedures (p = 0.266). DAP values (p = 0.001) and DSA runs (p = 0.026) decreased significantly by adding image registration guidance. Sampling and fluoroscopy times and skin dose showed no significant changes., Conclusion: Guidance based on registration of CBCT and previously acquired diagnostic CE-CT can aid in enhancing localization of the adrenal veins thereby increasing the success rate of first-attempt AVS with a significant decrease in the number of used DSA runs and, consequently, radiation dose required.

Objective: To determine the accuracy of cone beam CT (CBCT) guidance and CT guidance in reaching small targets in relation to needle path complexity in a phantom., Methods: CBCT guidance combines three-dimensional CBCT imaging with fluoroscopy overlay and needle planning software to provide real-time needle guidance. The accuracy of needle positioning, quantified as deviation from a target, was assessed for inplane, angulated and double angulated needle paths. Four interventional radiologists reached four targets along the three paths using CBCT and CT guidance. Accuracies were compared between CBCT and CT for each needle path and between the three approaches within both modalities. The effect of user experience in CBCT guidance was also assessed., Results: Accuracies for CBCT were significantly better than CT for the double angulated needle path (2.2 vs 6.7 mm, p<0.001) for all radiologists. CBCT guidance showed no significant differences between the three approaches. For CT, deviations increased with increasing needle path complexity from 3.3 mm for the inplane placements to 4.4 mm (p=0.007) and 6.7 mm (p<0.001) for the angulated and double angulated CT-guided needle placements, respectively. For double angulated needle paths, experienced CBCT users showed consistently higher accuracies than trained users [1.8 mm (range 1.2-2.2) vs 3.3 mm (range 2.1-7.2) deviation from target, respectively; p=0.003]., Conclusion: In terms of accuracy, CBCT is the preferred modality, irrespective of the level of user experience, for more difficult guidance procedures requiring double angulated needle paths as in oncological interventions., Advances in Knowledge: Accuracy of CBCT guidance has not been discussed before. CBCT guidance allows accurate needle placement irrespective of needle path complexity. For angulated and double-angulated needle paths, CBCT is more accurate than CT guidance.

Purpose: To assess whether the use of needle guidance devices can reduce fluoroscopy time and operator hand dose during cone-beam computed tomography-guided needle interventions., Materials and Methods: The freehand technique was compared with techniques employing two distinct needle holders and a ceiling-mounted laser guidance technique. Laser guidance was used either alone or in combination with needle holders. Four interventional radiologists were instructed to reach predetermined targets in an abdominal phantom using these techniques. Each operator used all six techniques three times. Fluoroscopy time, procedure time, operator hand dose, and needle tip deviation were obtained for all simulated needle interventions. All data are presented as median (ranges)., Results: All procedures were successfully completed within 2-4 minutes, resulting in a deviation from target of 0.8 mm (0-4.7). In freehand procedures, the fluoroscopy time to reach the target was 50 seconds (31-98 s). Laser guidance, used alone or in combination with needle holders, reduced fluoroscopy time to 31 seconds (14-68 s) (P<.02). The operator hand dose in freehand procedures was 275 μSv (20-603 μSv). Laser guidance alone or in combination with needle holders resulted in a reduction of the hand dose to<36 μSv (5-82 μSv) per procedure (P<.001). There were no statistically significant effects on hand dose levels or fluoroscopy time when the needle holders were employed alone., Conclusions: Compared with the freehand technique, all three tested needle guidance devices performed with equivalent efficiency in terms of accuracy and procedure time. Only the addition of laser guidance was found to reduce both fluoroscopy time and operator hand dose., (Copyright © 2013 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose: To determine the clinical value of two novel molecular imaging techniques: (11)C-choline positron emission tomography (PET)/computed tomography (CT) and ferumoxtran-10 enhanced magnetic resonance imaging (magnetic resonance lymphography [MRL]) for lymph node (LN) treatment in prostate cancer (PCa) patients. Therefore, we evaluated the ability of PET/CT and MRL to assess the number, size, and location of LN metastases in patients with primary or recurrent PCa., Methods and Materials: A total of 29 patients underwent MRL and PET/CT for LN evaluation. The MRL and PET/CT data were analyzed independently. The number, size, and location of the LN metastases were determined. The location was described as within or outside the standard clinical target volume for elective pelvic irradiation as defined by the Radiation Therapy Oncology Group. Subsequently, the results from MRL and PET/CT were compared., Results: Of the 738 LNs visible on MRL, 151 were positive in 23 of 29 patients. Of the 132 LNs visible on PET/CT, 34 were positive in 13 of 29 patients. MRL detected significantly more positive LNs (p < 0.001) in more patients than PET/CT (p = 0.002). The mean diameter of the detected suspicious LNs on MRL was significantly smaller than those detected by PET/CT, 4.9 mm and 8.4 mm, respectively (p < 0.0001). In 14 (61%) of 23 patients, suspicious LNs were found outside the clinical target volume with MRL and in 4 (31%) of 13 patients with PET/CT., Conclusion: In patients with PCa, both molecular imaging techniques, MRL and (11)C-choline PET/CT, can detect LNs suspicious for metastasis, irrespective of the existing size and shape criteria for CT and conventional magnetic resonance imaging. On MRL and PET/CT, 61% and 31% of the suspicious LNs were located outside the conventional clinical target volume. Therefore, these techniques could help to individualize treatment selection and enable image-guided radiotherapy for patients with PCa LN metastases., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Purpose: Operative treatment of giant omphalocele (OC) is still a challenge for pediatric surgeons. We were interested to ascertain whether published operative techniques for giant OC once advocated by their authors were still being used by these authors and whether the techniques had been modified or even abandoned for other techniques., Methods: Relevant studies concerning the treatment of giant OC were identified by an electronic search. Publication date of the articles was from 1967 to 2009. A questionnaire was sent to the first author or coauthor, unless contact details were unavailable. The described surgical techniques were categorized into primary closure, staged closure, and delayed closure., Results: Almost half of the authors (42%), independent of the initial technique used (primary, staged, or delayed closure), changed or stopped using their technique after the publication of the article. The change was not to one particular proven better technique. Herniation rate was lower in delayed closure (9% delayed vs 18% staged vs 58% primary)., Conclusions: The results of the questionnaire did not show a generally accepted method of treatment after more than 30 years of innovations in managing patients with a giant OC. There are generally 2 main treatment modalities: staged closure and delayed closure. Because of the lack of large patient numbers and late follow-up, long-term results of the published techniques are needed, and randomized multicenter trials based on these outcomes are recommended. Until then, we remain dependent on expert opinions., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Purpose: Long-term outcome and quality of life in omphalocele (OC) studies are mainly focused on cosmetic disorders with the abdominal scar and gastrointestinal disorders. The aim of this study was to compare long-term mortality, morbidity, and quality of life between patients with minor and giant OCs., Methods: Records of 89 minor and 22 giant OC children were reviewed. A questionnaire on general health was sent to all patients. A second questionnaire concerning quality of life and functional status; Darthmouth COOP Functional Health Assessment Charts/WONCA (COOP/WONCA) was sent to all patients aged 18 years or older and a peer control group., Results: Of the surviving patients (69 minor OC, 20 giant OC), 12 were lost to hospital follow-up. The first questionnaire was returned by 64 (83%) of 77 patients. There were no significant differences in gastrointestinal disorders. Cosmetic problems were experienced significantly more in giant OC. The results of the COOP/WONCA charts indicated a good to very good quality of life in both groups comparable to the control group., Conclusions: Our study indicates that after a high level of medical intervention perinatally, quality of life is good to very good in both groups and comparable to healthy young adults.

Aim: To compare the diagnostic accuracy of computed tomography (CT) and magnetic resonance imaging (MRI) in the diagnosis of lymph node metastases in prostate cancer., Methods: After a comprehensive literature search, studies were included that allowed construction of contingency tables for detection of lymph node metastases using CT or MRI. In addition, a summary receiver-operating characteristic (ROC) analysis was performed., Results: A total of 24 studies were included. For CT, pooled sensitivity was 0.42 (0.26-0.56 95% CI) and pooled specificity was 0.82 (0.8-0.83 95% CI). For MRI, the pooled sensitivity was 0.39 (0.22-0.56 95% CI) and pooled specificity was 0.82 (0.79-0.83 95% CI). The differences in performance of CT and MRI were not statistically significant., Conclusion: CT and MRI demonstrate an equally poor performance in the detection of lymph node metastases from prostate cancer. Reliance on either CT or MRI will misrepresent the patient's true status regarding nodal metastases, and thus misdirect the therapeutic strategies offered to the patient.

Purpose: The clinical diagnosis and management of invasive lobular carcinoma (ILC) of the breast presents difficulties. Magnetic resonance imaging (MRI) has been proposed as the imaging modality of choice for the evaluation of ILC. Small studies addressing different aspects of MRI in ILC have been presented but no large series to date. To address the usefulness of MRI in the work-up of ILC, we performed a review of the currently published literature., Materials and Methods: We performed a literature search using the query "lobular AND (MRI OR MR OR MRT OR magnetic)" in the Cochrane library, PubMed and scholar.google.com, to retrieve all articles that dealt with the use of MRI in patients with ILC. We addressed sensitivity, morphologic appearance, correlation with pathology, detection of additional lesions, and impact of MRI on surgery as different endpoints. Whenever possible we performed meta-analysis of the pooled data., Results: Sensitivity is 93.3% and equal to overall sensitivity of MRI for malignancy in the breast. Morphologic appearance is highly heterogeneous and probably heavily influenced by interreader variability. Correlation with pathology ranges from 0.81 to 0.97; overestimation of lesion size occurs but is rare. In 32% of patients, additional ipsilateral lesions are detected and in 7% contralateral lesions are only detected by MRI. Consequently, MRI induces change in surgical management in 28.3% of cases., Conclusion: This analysis indicates MRI to be valuable in the work-up of ILC. It provides additional knowledge that cannot be obtained by conventional imaging modalities which can be helpful in patient treatment.

Diagnosis of colonic duplication can pose a potential problem even for those familiar with gastro-intestinal tract duplications in general but unaware of the condition due to its rarity and its apparently bimodal clinical presentation. In this report of five cases of surgically proven pediatric colonic duplication, we illustrate how the condition manifests clinically and describe the imaging features in an attempt to illustrate this bimodal presentation of the condition. The possible etiology, associated congenital anomalies and modes of clinical presentation are reviewed based on literature review as well as on our own experience.

Purpose: To prospectively evaluate the feasibility of ferumoxtran-10-enhanced magnetic resonance (MR) imaging at high magnetic field strength (3.0 T) and to compare image quality between 1.5- and 3.0-T MR imaging in terms of lymph node detection in patients with prostate cancer., Materials and Methods: This study was institutional review board approved, and all patients gave written informed consent. Forty-eight consecutive patients aged 51-79 years (mean, 65.5 years) with prostate cancer were enrolled. T2*-weighted 1.5- and 3.0-T MR images of the pelvis were acquired in a sagittal plane parallel to the psoas muscle 24 hours after ferumoxtran-10 administration. A pelvic and body phased-array coil was used and yielded an in-plane resolution of 0.56 x 0.56 x 3.00 mm at 1.5 T and 0.50 x 0.50 x 2.50 mm at 3.0 T. All images were evaluated by three readers for total image quality, lymph node border delineation, muscle-fat contrast, and vessel-fat contrast. Statistical significance was calculated by using the Mann-Whitney U test. Subsequently, the general linear mixed model was used to estimate the contributions of three factors-patient, reader, and technique-to the variability of the imaging results., Results: Significantly (P < .05) better muscle-fat contrast, vessel-fat contrast, lymph node border delineation, and total image quality were observed at 3.0-T MR imaging. The general linear mixed model revealed that the variability of all results could be attributed to the use of 3.0-T imaging., Conclusion: Ferumoxtran-10-enhanced MR imaging can be performed at high magnetic field strengths and result in improved image quality, which may lead to improved detection of small positive lymph nodes., ((c) RSNA, 2006.)

Purpose: A new inferior vena cava filter was evaluated in vivo to determine the percutaneous retrievability after an implantation period of up to 18 days., Materials and Methods: The inferior venae cavae of six goats were percutaneously implanted with three filters, and one animal received two filters. To assess filter stability, a plain radiograph was obtained after 7-9 days and on the day of retrieval. After cavography, filter retrieval with an endovascular snare and retrieval catheter was performed in three animals after 12 days and in three others after 14 days. In one animal, retrieval of one filter was performed after 18 days, and one filter was intended to be permanent. Twenty-eight days after filter retrieval, cavography was performed before inferior vena cava removal for gross and histologic examination., Results: All filters (N = 20) were implanted without complications. There was no migration during the implantation period. Preretrieval cavography demonstrated all filters to be patent and centered. Filters intended for retrieval (n = 19) were all successfully extracted at 12 (nine filters), 14 (nine filters), and 18 days (one filter). For the animal with the filter extracted at 18 days, one filter remained in situ intentionally. Postretrieval cavography showed no visible signs of vessel wall anomalies. There were no complications during the 28 days of follow-up after retrieval. Presacrifice cavography showed no evidence of caval wall abnormalities. In all animals, gross examination of the inner wall of the explanted vena cava showed only minimal macroscopic changes. The struts of the filter in situ for 46 days (18 days with 28 days of follow-up) were overgrown with neointima. Histological study of the 19 filter retrieval sites revealed no to moderate intima proliferation, minimal residual signs of hemorrhages, and no or only occasional slight inflammatory reaction., Conclusions: In this animal model, the new vena cava filter demonstrated event-free retrieval, without postretrieval complications, up to 18 days postimplantation. After implantation of 46 days, the filter showed neointima overgrowth of the struts.

Purpose: to determine the 12 months success rate with a balloon expandable, flexible stainless steel stent in iliac artery obstructions., Materials and Methods: one-hundred and twenty-six consecutive patients with iliac obstructive disease and who demonstrated an unsatisfactory angioplasty result with a post-dilatation gradient of at least 10 mmHg, or a primary occluded lesion were included in the study. Follow-up was by Doppler sonography, ankle pressures with and without exercise and clinical parameters., Results: after stent placement, the mean percentage diameter stenosis decreased from 79 to 4%, with a mean intra-arterial pressure gradient of 3 mmHg. Primary stent patency was 94% at 6 months and 89% at 12 months. Primary clinical result at 6 months was 88% and at 12 months 81%. Primary assisted clinical result (after re-pta) at 6 and 12 months was 89 and 86%, respectively. The Ankle Brachial Index (ABI) after exercise at 1 month follow-up was reduced from 0.88 to 0.75, with minor deterioration at 6 months to 0.72, and at 12 months to 0.68. The 1, 6, and 12 months follow-up Piek Systolic Velocity (PSV) ratios across the stented lesions remained stable at a mean of 1.4, 1.6, and 1.6, respectively. However, respectively 44, 39 and 34% of the patients still experienced symptoms of claudication., Conclusions: the results presented here support the suggestion stenting to be an effective device in the treatment of iliac artery obstructive disease. This study also, confirms other study results concerning haemodynamic patency after iliac stenting on the indication of a 10 mmHg pressure gradient after pta and the discrepancy between good haemodynamic patency and clinical result.

Parallel tubular structures (PTS) and/or the associated electron-dense granules, thought to contain molecules responsible for target cell lysis, can be detected in the cytoplasm of lymphocytes with large granular lymphocyte (LGL) morphology. In the present study we compared PTS presence in freshly isolated peripheral blood lymphocytes and peripheral blood lymphocytes incubated overnight in the presence of human pooled serum, sera from patients with Hodgkin's disease and interferon-alpha. Under all conditions we found PTS in the majority of CD16+ cells (64.3-74.8%) but less than 41.8% in CD57+ cells. In the case of double-labeled lymphocytes, 41.0-61.7% CD16+/8+ but only 24.2-27.5% CD57+/8+ cells were PTS+. Thus, in all cases where lymphocytes expressed CD16 antigen there was a high percentage of PTS positivity. Although the PTS+ cells exhibited phenotypic heterogeneity there was, except for a proportion of CD57+ lymphocytes which exhibited less of the characteristic LGL features, generally LGL morphological homogeneity. CD16 lymphocytes are potentially more cytotoxic than CD57 and CD8 cells. Taking this into consideration, the presence of the PTS in the majority of CD16 cells suggests an important role for PTS in target cell lysis.

Activation of natural killer (NK) cell activity is one of the immune functions which can be altered by the interferons (IFNs). We previously incubated healthy donor peripheral blood lymphocytes (PBMC) in the presence of natural (n) IFN-alpha and found induction of granular lymphocytes, a proportion of which expressed CD 8 and CD 57. In the present study we further delineated the membrane characteristics of these induced granular lymphocytes and observed the greatest proportion to be CD 16+, with lesser proportions positive for CD 8, CD 57, or coexpressing CD 16 and CD 8. Thus, nIFN-alpha-induced granular lymphocytes have both the morphological and membrane characteristics of functional NK cells. However, in contrast to nIFN-alpha, incubations with recombinant (r) IFN-alpha and n- and rIFN-gamma were found to only enhance NK activity; the concomitant increase in granular lymphocytes as observed after nIFN-alpha incubation was absent. Therefore, even though the different IFNs applied had comparable effects on the function of cytotoxic effector cells, taking into account the observed morphological discrepancy, the unknown mechanisms or pathways by which this is achieved are apparently not identical.

A double immunogold-labeling method in immunoelectron microscopy was used for simultaneous detection of two antigens by monoclonal antibodies [OKT 8 (CD 8), anti-Leu-7, anti-Leu-11b (CD 16)] on lymphocytes in suspension. The combination of gold probe size (5 nm and 15 nm) and monoclonal antibody was found to be decisive for detecting double-labeled cells with the OKT 8+, Leu-11b+ phenotype. The combinations of OKT 8 labeled with the 5-nm gold probe (OKT 8(5] and anti-Leu-11b with the 15-nm gold probe (Leu-11b15) gave double-labeled cells; the reverse situation, using OKT 8 with a 15-nm gold probe (OKT 8(15] and anti-Leu-11b with a 5-nm gold probe (Leu-11b5), did not. Double-labeled OKT 8+, Leu-7+ cells were detected irrespective of which gold probe combination was applied. Our findings indicate that although the double immunogold-labeling method is well suited for study of lymphocyte subsets, it is important to determine suitable combinations of gold probe sizes and monoclonal antibodies for the lymphocyte subset under study, taking into account surface antigen density, so that double labeling ensues.

The induction by IFN-alpha in peripheral blood lymphocytes of parallel tubular structures (PTS) and/or electron-dense granules occurring in a minority of peripheral blood lymphocytes was examined. IFN reportedly augments natural killer (NK) cell activity of large granular lymphocytes (LGL); these cells contain PTS and/or electron-dense granules. Normal peripheral blood mononuclear cells were incubated with IFN-alpha and surface antigen expression was measured by means of indirect immunofluorescence and, at the ultrastructural level, using gold labelled monoclonal antibodies. Surface antigen reactivity with the monoclonal antibodies OKT 3, 4, 8 and Anti-Leu-7 (HNK-1) showed no difference between the IFN-alpha incubation and non-IFN-alpha groups. However, electron microscope investigation revealed significant absolute increases in the percentage of OKT 8+ and Anti-Leu-7+ cells which were PTS-positive after IFN-alpha treatment compared with the control groups. The cytotoxicity assay using the K562 cell line showed enhanced lytic activity. Our results suggest that cells coexpressing the OKT 8 and Leu-7 antigens may be responsible for a minor proportion of the increase in PTS but that IFN-alpha mainly induces PTS and/or associated structures in cells which express the OKT 8+ antigen. These PTS+/OKT 8+ cells may contribute to enhanced cell cytotoxicity.

While maintaining the arterial CO2 tension constant near the normal level of the dog (4.3 kPa), we studied the influence of decreasing cardiac output on both the arterial and mixed-venous blood acid-base status in anaesthetized, artificially ventilated dogs. Cardiac output was manipulated by applying positive end-expiratory pressure (PEEP), and by beta-adrenergic blockade to suppress a compensatory heart rate response. The systemic vascular response was attenuated by alpha-adrenergic blockade. Metabolic rate remained virtually unchanged when cardiac output decreased. Under these conditions a fall in cardiac output led to a shift of the arterial acid-base status in the direction of a metabolic acidosis. The changes occurring in the mixed-venous blood resembled those of an in-vivo CO2 bufferline, with the shift being such as if a respiratory acidosis was developing.