Quantitative analysis of phantom studies of 111In and 68Ga imaging of neuroendocrine tumours.

BACKGROUND: Nuclear medicine imaging of neuroendocrine tumours is performed either by SPECT/CT imaging, using 111In-octreotide or by PET/CT imaging using 68Ga-radiolabelled somatostatin analogs. These imaging techniques will give different image quality and different detection thresholds for tumours, depending on size and activity uptake. The aim was to evaluate the image quality for 111In-SPECT and 68Ga-PET imaging, i.e. the smallest volume possible to visualize for different source-to-background activity ratios. The accuracy of quantification of lesion volume and activity was also investigated to develop an objective evaluation for radionuclide therapy eligibility. The phantom study was performed using the NEMA IEC Body Phantom with six hot spheres having inner diameters of 10, 13, 17, 22, 28, and 37 mm, filled with either 68Ga or 111In with sphere-to-background ratios (SBRs) of no background activity, 5:1, 2.5:1, and 1.25:1. Activity ratios of 1.25:1 and 2.5:1 are clinically found for lesions close to the liver and spleen. Clinical acquisition and reconstruction protocols were applied. Line profiles were drawn to evaluate the smallest detectable volume within a given SBR. Recovery curves based on threshold-based VOIs, threshold-based VOIs adapted to the background and CT-based ROIs were obtained for all SBRs and sphere diameters, allowing for quantification. RESULTS: The 10-mm sphere was not possible to detect in SPECT images. It was detectable in PET images for SBRs of 2.5:1 and higher. In a background corresponding to the activity uptake in the liver, spheres larger than 22-37 mm were detectable in the 111In-SPECT images and spheres larger than 13-22 mm were detectable in the 68Ga-PET images. The maximum activity concentration was accurately quantified for spheres larger than 22 mm in the PET images; however, the quantification was impaired by sphere size and background activity. CONCLUSIONS: It was not possible to detect the 10-mm sphere in any of the SPECT images. In a background corresponding to the activity uptake in the liver, spheres larger than approximately 30 mm were visible in the 111In-SPECT images and spheres larger than approximately 17 mm were visible in the 68Ga-PET images. Sphere diameter and background activity strongly affect the possibility of a correct quantification.

Editor's Choice - The National Norwegian Carotid Study: Time from Symptom Onset to Surgery is too Long, Resulting in Additional Neurological Events.

OBJECTIVE/BACKGROUND: The objective was to observe for 1 year all patients in Norway operated on for symptomatic carotid stenosis with respect to (i) the time from the index event to surgery and neurological events during this time; (ii) the level in the healthcare system causing delay of surgical treatment; and (iii) the possible relationship between peri-operative use of platelet inhibitors and neurological events while awaiting surgery. METHODS: This was a prospective national multicentre study of a consecutive series of symptomatic patients. Patients were eligible for inclusion when referred for surgery. An index event was defined as the neurological event prompting contact with the healthcare system. All 15 departments in Norway performing carotid endarterectomy (CEA) participated. RESULTS: Three hundred and seventy one patients were eligible for inclusion between 1 April 2014 and 31 March 2015, and 368 patients (99.2%) were included. Fifty-four percent of the patients contacted their general practitioner on the day of the index event. Primary healthcare referred 84.2% of the patients to hospital on the same day as examined. In hospital median time from admission to referral for vascular surgery was 3 days. Median time between referral to the operating unit and actual CEA was 5 days. Overall, 61.7% of the patients were operated on within 2 weeks of the index event. Twelve patients (3.3%) suffered a new neurological event while awaiting surgery. The percentage of patients on dual antiplatelet therapy was lower (25.0%) in this group than among the other patients (62.6%) (p = .008). The combined 30 day mortality and stroke rate was 3.8%. CONCLUSION: This national study with almost complete inclusion and follow-up shows that the delays occur mainly at patient level and in hospital. The delay is associated with new neurological events. Dual antiplatelet therapy is associated with reduced risk of having a new neurological event before surgery.

Effect of an antibiotic checklist on length of hospital stay and appropriate antibiotic use in adult patients treated with intravenous antibiotics: a stepped wedge cluster randomized trial.

OBJECTIVES: Quality indicators (QIs) have been developed to define appropriate antibiotic use in hospitalized patients. We evaluated whether a checklist based on these QIs affects appropriate antibiotic use and length of hospital stay. METHODS: An antibiotic checklist for patients treated with intravenous antibiotics was introduced in nine Dutch hospitals in a stepped wedge cluster randomized trial. Prophylaxis was excluded. We included a random sample before (baseline), and all eligible patients after (intervention) checklist introduction. Baseline and intervention outcomes were compared. Primary endpoint was length of stay (LOS), analysed by intention to treat. Secondary endpoints, including QI performances, QI sum score (performance on all QIs per patient), and quality of checklist use, were analysed per protocol. RESULTS: Between 1 November 2014 and 1 October 2015 we included 853 baseline and 5354 intervention patients, of whom 993 (19%) had a completed checklist. The LOS did not change (baseline geometric mean 10.0 days (95% CI 8.6-11.5) versus intervention 10.1 days (95% CI 8.9-11.5), p 0.8). QI performances increased between +3.0% and +23.9% per QI, and the percentage of patients with a QI sum score above 50% increased significantly (OR 2.4 (95% CI 2.0-3.0), p<0.001). Higher QI sum scores were significantly associated with shorter LOS. Discordance existed between checklist-answers and actual performance. CONCLUSIONS: Use of an antibiotic checklist resulted in a significant increase in appropriateness of antibiotic use, but not in a reduction of LOS. Low overall checklist completion rates and discordance between checklist-answers and actual provided care might have attenuated the impact of the checklist.

Early postpartum mitral valve thrombosis requiring extra corporeal membrane oxygenation before successful valve replacement.

Pregnancy is associated with an increased risk of thrombosis in women with mechanical prosthetic heart valves. We present the case of a 29-year-old woman who developed early postpartum mitral valve thrombus after an elective cesarean delivery. The patient had a mechanical mitral valve and was treated with warfarin in the second trimester, which was replaced with high-dose dalteparin during late pregnancy. Elective cesarean delivery was performed under general anesthesia at 37weeks of gestation. The patient was admitted to the intensive care unit for postoperative care and within 30min she developed dyspnea and hypoxia requiring mechanical ventilation. She deteriorated rapidly and developed pulmonary edema, worsening hypoxia and severe acidosis. Urgent extra corporeal membrane oxygenation was initiated. Transesophageal echocardiography revealed a mitral valve thrombus. The patient underwent a successful mitral valve replacement after three days on extra corporeal membrane oxygenation. This case highlights the importance of multidisciplinary care and frequent monitoring of anticoagulation during care of pregnant women with prosthetic heart valves.

Introduction of embryonic stem cells into vein grafts reduces intimal hyperplasia in mice.

AIM: Atherosclerosis with its cardiovascular events including cardiac and peripheral ischemia represents the main cause of death in the developed countries. Although interventional treatments like percutaneous transluminal angioplasty or stents are increasingly applied for the treatment of peripheral arterial disease, they are not always technically applicable or durable and bypass surgery is needed. Compared to synthetic grafts, vein grafts show a better patency especially when used for the lower leg as well as a lower risk for infection compared to synthetic grafts. Still the long-term patency rates are unsatisfactory due to accelerated intimal hyperplasia, a thickening of the vessel wall. The aim of this study was to elucidate, if the implantation of embryonic stem cells into vein grafts can reduce the development of intimal hyperplasia in a mouse in vivo model. METHODS: In this study we implanted LacZ-tagged (ROSA26) murine embryonic stem cells into decellularized vein grafts. Control groups were: 1) untreated veins; 2) decellularized veins; 3) decellularized veins with gel and plastic film; and 4) decellularized veins with smooth muscle cells in gel surrounded by plastic film. Six weeks after insertion into the carotid artery of mice, the grafts were excised and analyzed immunohistochemically, morphologically, and by x-gal staining and compared to the control groups. The Mann-Whitney U test was used to compare groups. Statistical significance was indicated by a value of P<0.05. RESULTS: Decellularized veins with implanted stem cells showed significantly less intimal thickening compared to all control groups (intimal hyperplasia vs. luminal circumference mean±SD 7.3±3.5 µm, median 8 µm). The control groups: 1) untreated veins (60.3±25.5 µm, median 58.5 µm); 2) decellularized veins (53.9±22.4 µm, median 48.4 µm); 3) decellularized veins with gel and plastic film (70.6±22.4 µm, median 72.6 µm); and 4) decellularized veins with smooth muscle cells in gel surrounded by plastic film (73.5±18.1 µm, median 73.6 µm) all showed the same high degree of intimal hyperplasia. CONCLUSION: This study demonstrates that embryonic stem cells have a therapeutic competence to favourably modulate intimal hyperplasia in vivo.

Endovascular treatment of descending thoracic aortic disease. A single center experience.

AIM: Aim of the study was to assess if endovascular treatment is a feasible alternative in patients with descending thoracic aortic disease. METHODS: Seventy-three patients were admitted for stent-grafting of descending thoracic aortic disease during the period 1997-2008. The majority of the patients had aneurysm (35) or type B dissection (21), but also traumas, penetrating ulcers and other conditions were treated. Sixteen (22%) were unfit for open surgery. Thirty-four (47%) of the patients were symptomatic and 18 had rupture. The primary technical success rate was 96%. RESULTS: Early mortality (<30 days) for the whole group was 3%. Early endoleak (<30 days) was identified in 11 patients (15%) of whom 4 (5%) had a secondary procedure. In addition, two trauma patients required insertion of a new stent-graft due to stent-graft collapse. Two patients had stroke, one had paraplegia and two paraparesis. Mean follow-up was 3.1 years (range 0-12 years). Late endoleak (>30 days) was identified in 5 patients (7%) treated by 6 secondary procedures. One patient (1.7%) had an explant. Two patients have had extensions of endografts due to increasing diameter of the aorta at the distal end of the stent-graft. CONCLUSION: Endovascular treatment seems to be a viable alternative in patients with descending thoracic aortic disease.

Effect of multilayer high-compression bandaging on ankle range of motion and oxygen cost of walking.

OBJECTIVE: To evaluate the effects of multilayer high-compression bandaging on ankle range of motion, oxygen consumption and subjective walking ability in healthy subjects. METHOD: A volunteer sample of 22 healthy subjects (10 women and 12 men; aged 67 [63-83] years) were studied. The intervention included treadmill-walking at self-selected speed with and without multilayer high-compression bandaging (Proforeº), randomly selected. The primary outcome variables were ankle range of motion, oxygen consumption and subjective walking ability. RESULTS: Total ankle range of motion decreased 4% with compression. No change in oxygen cost of walking was observed. Less than half the subjects reported that walking-shoe comfort or walking distance was negatively affected. CONCLUSION: Ankle range of motion decreased with compression but could probably be counteracted with a regular exercise programme. There were no indications that walking with compression was more exhausting than walking without. Appropriate walking shoes could seem important to secure gait efficiency when using compression garments.

Findings on how adolescents cope with cancer--a matter of methodology?

OBJECTIVES: The various conclusions drawn from previous studies on how adolescents cope with cancer might partly be explained by methodological issues. The aim was to explore how adolescents recently diagnosed with cancer report that they cope with disease- and treatment-related distress in response to closed- and open-ended questions, respectively. METHODS: Adolescents diagnosed with cancer 4-8 weeks ago (N=56) answered closed- and open-ended questions over the telephone about which coping strategies they use to cope with physical concerns, personal changes, feelings of alienation, and worries. RESULTS: In response to closed-ended questions, most adolescents reported using emotion-focused coping (Accepting and Minimising) while, in response to open-ended questions, meaning-based (i.e. Positive thinking) and problem-focused (i.e. Problem solving) coping were most often mentioned. A majority reported using Minimising and Seeking support in response to closed-ended questions, but very few adolescents mentioned using these strategies in response to open-ended questions. CONCLUSIONS: Adolescents' reports of how they cope with disease- and treatment-related distress vary depending on antecedent closed- and open-ended questions. Responses to closed-ended questions appear to be more indifferent to aspects of distress than responses to open-ended questions. Strategies representing meaning-based coping should be included in future studies investigating how adolescents recently diagnosed with cancer cope with disease- and treatment-related distress.

Improved patency and reduced intimal hyperplasia in PTFE grafts with luminal immobilized heparin compared with standard PTFE grafts at six months in a sheep model.

AIM: The aim of this study was to compare the performance of polytetrafluoroethylene (PTFE) grafts with luminal coating of immobilized heparin to that of standard PTFE grafts at six months. METHODS: Twenty-eight common carotid arteries in fourteen sheep were bypassed with heparin-coated PTFE grafts (6 mm diameter, 6 cm length) on one side and standard PTFE grafts on the other. The grafts were explanted after six months. The thickness of intimal hyperplasia (IH) in open grafts was measured with histomorphometrical methods. RESULTS: Two of 14 heparinized PTFE grafts and nine of 14 grafts in the control PTFE-group were occluded at explantation (P=0.006). Six-month patency rates for heparinized PTFE grafts and for standard PTFE grafts were 86% and 36%, respectively. Mean graft anastomotic IH thickness in open grafts were 0.074 mm for heparinized PTFE grafts and 0.259 mm for PTFE-grafts (P=0.006). CONCLUSION: PTFE grafts with luminal coating containing immobilized heparin had significantly better patency and recruited less intimal hyperplasia than standard PTFE grafts at six months.

Empirically derived psychosocial states among adolescents diagnosed with cancer during the acute and extended phase of survival.

BACKGROUND: To, during the acute and extended phase of survival, identify psychosocial states among adolescents diagnosed with cancer and to analyse these in relation to demographic and clinical characteristics and self-reported depression. PATIENTS AND METHODS: Participants completed the Hospital Anxiety and Depression Scale and two subscales, Vitality and Mental Health, in the SF-36 4-8 weeks (T1) (n = 61), 6 (T2) (n = 57), 12 (T3) (n = 50), and 18 (T4) months (n = 48) after diagnosis. I-State as Object of Analysis was used to identify a finite set of states based on three dimensions. Cluster analysis was carried out using Ward's method. RESULTS: Five states were obtained: psychosocial dysfunction (state A) and poor (B), incomplete (C), good (D), and excellent (E) psychosocial function. At T1, more adolescents than expected by chance were in states A (P < 0.05) and C (P < 0.01) and fewer in states D (P < 0.05) and E (P < 0.001). At T4, more adolescents than expected by chance were in state E (P < 0.001) and fewer in state C (P < 0.05). Female gender and being in late adolescence when diagnosed is related to worse psychosocial function. CONCLUSION: The findings provide support for subgroups of adolescents whose level of vitality, mental health, and anxiety differ during the acute and extended phase of survival of cancer. Clinical interventions tailored to the level of impairment as determined by the clusters may result in better psychosocial outcomes.

Postnatal cerebral infection leading to hemiplegic cerebral palsy: functional limitations and disability of 13 children in Sweden.

PURPOSE: To describe the motor function and disability of children with postnatal cerebral infection leading to hemiplegia, and to determine the severity of their motor disability. METHOD: The disablement process was used to describe these children. Participants included 13 children (7 girls and 6 boys, mean age 9.8 years). Traditional neurological assessment methods, together with the Movement Assessment Battery for Children and Paediatric Evaluation of Disability Inventory, were used. The children's non-hemiplegic sides were also tested. To determine severity of motor disability, new definitions were created that reflected the child's balance and fine-motor ability in relation to expected performance at his or her age. RESULTS: The children had involvement of the non-hemiplegic leg and arm in all but one case. Balance and hand function was impaired in all. Hypotonicity was present in 10 children, weakness of hip muscles in 9. There was great variation in grip function. Motor difficulties dominated during pre-school years, whereas the dominant problem of all school-age children was social and communication skills. Behavioural, communicative, and chewing and swallowing problems were common. CONCLUSIONS: A postnatal infectious aetiology influences function on both the hemiplegic and non-hemiplegic side. In school-age children, social skills and communication difficulties are more pronounced than motor problems. The results of this study encourage the use of methods standardized for age where force dynamics and quality of movement are assessed.

Are there any positive consequences of childhood cancer? A review of the literature.

The aim was to investigate whether there are any positive consequences of childhood cancer. Studies published 1990-2005 reporting survivors' descriptions of positive consequences of childhood cancer were identified through a search in the databases CINAHL, PsycINFO, and PubMed. According to a manifest content analysis, positive consequences were referred to three themes: life values, relations to others, and relation to self. A second search in the same databases was conducted to identify studies investigating whether survivors of childhood cancer differ from comparison groups with regard to variables assigned to these themes. In these studies, no conclusions about positive consequences with regard to the theme life values can be drawn, as only one study was identified. In addition, only a small minority of findings from comparative studies indicate that childhood cancer has any positive consequences with regard to relations to others and relation to self. A majority of the results indicate that survivors do not differ from comparison groups, whereas some findings highlight that friendship and marital status are areas of concern, and parenthood and sexuality are areas of potential concern. It is recommended that survivors of childhood cancer are followed up by a multi-professional team, focusing not only on the survivors' health status but also on relations to family, friends, and partners.

Participation in age-related activities and influence of cultural factors--comments from youth and parents of children with postnatal post infectious hemiplegia in Stockholm, Sweden.

PURPOSE: To investigate whether children with postnatal post-infectious hemiplegic cerebral palsy, and their parents, felt that participation in activities typical for the child's age and gender was affected. To identify factors, intra- and extra-personal that influenced disability with emphasis on factors related to immigration. METHOD: Interviews with six youths and 15 caregivers regarding the child's ability to participate in age-related activities, the consequences of disability in their home country compared to Sweden, and whether immigration influenced being a parent to a disabled child. RESULTS: All reported large difficulties participating in age-related activities. Positive and negative differences in participation in different cultures were described. War, culture, eating habits, hygiene habits, and school could differ and create difficulties when in Sweden. Language skills and intra personal factors influenced information gathering and participation in parental activities. CONCLUSIONS: Surprisingly large difficulties in participation may separate those with a postnatal post-infectious aetiology from hemiplegia of other aetiologies. High degrees of additional impairments may influence participation more than the physical disability. Language skills and cultural factors influence ability to seek and gain information. A mutual process where both Swedes and immigrants know traditions of care for disabled in both places may create understanding and improved dialogue.

Photodynamic therapy reduces intimal hyperplasia in prosthetic vascular bypass grafts in a pig model.

BACKGROUND: Bypass surgery has a failing frequency of 30% during the first year, mainly due to intimal hyperplasia (IH). This negative effect is most pronounced in artificial grafts. Photodynamic therapy (PDT) is a technique in which light activates photosensitizer dyes to produce free-radicals resulting in an eradication of cells in the vascular wall. The aim of this study was to determine the effectiveness of PDT to reduce IH in a preclinical porcine PTFE bypass model. MATERIAL AND METHODS: Ten pigs were used. After a pilot PDT dosimetry study (n=3) PTFE grafts were bilaterally placed into the circulation as bypasses from the common to the external iliac arteries (n=7). The right sides served as controls (C). Before implantation of the left grafts, the arterial connecting sites of the left distal anastomoses were PDT-treated. The arteries were pressurized at 180 mmHg for 5 minutes with the photosensitizer Methylene Blue (330 microg/ml), and thereafter endoluminally irradiated with laser light (lambda = 660 nm, 100 mW/cm(2), 150 J/cm(2)). After 4 weeks the specimens were retrieved and formalin fixed. Cross sections through the midportions of the distal anastomoses and the grafts were used for histology, immunohistochemistry to identify inflammatory cells and morphometric evaluation (n=7). RESULTS: No systemic side effects and no graft occlusions were noted. PDT-treated anastomoses showed reduced IH in the mid-portions of the anastomoses (Area of IH: microm(2)/microm graft: C: 6970+/-1536, PDT: 2734+/-2560; P<0.005) as well as in the grafts (C: 5391+/-4031, PDT: 777+/-1331; P<0.02). The number of inflammatory cells per microscopic field was increased after PDT (C: 24+/-16, PDT: 37+/-15; P<0.009). CONCLUSIONS: Adjuvant PDT, performed in an endovascular fashion, was a safe method to reduce prosthetic graftstenosis in a preclinical setting. This study underscores the clinical potential of PDT to inhibit the development of clinical bypass graftstenosis.

Age and gender differences in VO2max in Swedish obese children and adolescents.

AIM: To describe age and gender differences in estimated maximum oxygen uptake (VO2max) and participation in organized physical activity in Swedish obese children and adolescents, and compare the results with an age-matched reference group representative of the general population. METHODS: Two hundred and nineteen obese children (102 boys, 117 girls, aged 8-16 years, Body Mass Index (BMI) 24.3-57.0 kg.m-2) performed a submaximal bicycle ergometry test and an interview concerning participation in organized physical activity. RESULTS: The obese children had lower relative VO2max (p<0.001) than the reference group. In contrast to the reference group no age or gender differences were detected in the obese children aged 11-13 years and 14-16 years. With increased age (after 11 years) the obese children participated less in organized physical activity than the reference group (p<0.001). In obese adolescents, participation in organized physical activity in leisure time explained 7% and BMI 45% of the variance in relative VO2max. CONCLUSION: The obese children had lower relative VO2max, and participated less in organized physical activity than the reference group. The variance in relative VO2max was primarily explained by BMI. Obese adolescents, especially boys, were found to be at risk of physical inactivity.

Positive and negative consequences with regard to cancer during adolescence. Experiences two years after diagnosis.

OBJECTIVES: The purpose was to explore negative and positive consequences of cancer during adolescence experienced two years after diagnosis. METHODS: Two years after diagnosis 38 persons, 15-21 years old, were asked two questions over the telephone: What, if anything, is bad for you due to the cancer disease? and What, if anything, is good for you due to the cancer disease? The answers were analysed by content analysis. RESULTS: Four categories of negative experiences were identified: a problematic body; unpleasant thoughts and feelings; outside the circle of friends; and difficulties with schoolwork. Six categories of positive experiences were identified: a more positive view of life; good self-esteem; knowledge and experience with regard to disease and hospital care; good relations; broader perspectives; and material gains. CONCLUSIONS: Two years after diagnosis those struck by cancer during adolescence experience not only a number of negative, but also positive, consequences of the cancer disease and its treatment.

Discovery of highly potent small molecule kallikrein inhibitors.

Uncontrolled kallikrein activation is involved in diseases such as hereditary angioedema, bacterial septic shock and procedures such as cardiopulmonary bypass. Here we report a series of small molecule compounds that potently inhibit kallikrein activity in vitro. Kinetic studies indicate that some of these compounds are slow binding inhibitors of kallikrein with Ki final less than a nanomolar. The ability of these compounds to inhibit the activity of kallikrein was further confirmed in a plasma model by quantitating the release of bradykinin, an endogenous cleavage product of plasma kallikrein. To understand the inhibitory mechanism of the selected compounds toward kallikrein, the interactions between the selected compounds and kallikrein was explored using molecular modeling based on the information of crystal structures of TF/FVIIa and kallikrein. The information presented in the current study provides an initial approach to develop more selective and therapeutically useful small molecule inhibitors.

Physical activity, body composition and physical self-esteem: a 3-year follow-up study among adolescents in Sweden.

AIMS: To measure physical activity by means of daily pedometer steps, body composition, expressed as body mass index (BMI) and bioelectrical impedance as percent body fat, and perceived physical self-esteem and additionally, to evaluate eventual predictors for a healthy lifestyle i.e., highly physically active, normal weighted and a high physical self-esteem in a follow-up group. METHODS: During autumn 2000 physical activity level was assessed and BMI was calculated in 871 children aged 7-14 in south eastern Sweden and in 501 of these, physical self-esteem were also assessed. During autumn 2003 a total of 375 adolescents aged 15-18 were assessed using the same methodology and additionally percent body fat was measured. Ninety-three of these adolescents (46 girls), were also measured in 2000 and they formed the follow-up group. RESULTS: In the follow-up group a significant increase in BMI and stability in physical self-esteem in boys and girls, and in boys a significant decrease in daily steps was found 3 years later. Strongest predictor to be highly physically active, maintain normal BMI and high self-esteem 3 years later, i.e., to have a healthy lifestyle, was for girls increased self-esteem and for boys a decreased BMI. CONCLUSION: Consequently, for a healthy lifestyle, promoting physical self-esteem in girls and weight control in boys is of great importance in early adolescence.

Healing of PTFE grafts in a pig model recruit neointimal cells from different sources and do not endothelialize.

OBJECTIVES: The aim of this study was to analyze the cellular sources for the neointima and the cell type that is lining the lumen in artificial grafts implanted in pigs. MATERIALS AND METHODS: We used polytetrafluoroethylene grafts as bypasses from the common to the external iliac arteries. The animals were sacrificed after 1, 4, 7, 14, 21, 30, 60 and 90 days. Morphological, immunohistochemical and electron microscope assessments were made. RESULTS: After 7 days a circumferential neoadventitia was formed. At day 14 isolated cellular islets of proliferating cells were observed on the luminal side of the graft without connection to the neoadventitia or the adjacent arteries. In the anastomotic regions at day 14 we observed an isolated neointima in contact with the adjacent artery. The cells lining the lumen had characteristics of both smooth muscle cells and endothelial cells. CONCLUSIONS: Our study suggests that in artificial porcine grafts, the perivascular tissue, the blood and the adjacent artery contribute to the formation of the neointima. The luminal surface is covered by a hybrid cell with both smooth muscle cell and endothelial cell properties.