Selection of image fusion quality measures: objective, subjective, and metric assessment.

Accurate quality assessment of fused images, such as combined visible and infrared radiation images, has become increasingly important with the rise in the use of image fusion systems. We bring together three approaches, applying two objective tasks (local target analysis and global target location) to two scenarios, together with subjective quality ratings and three computational metrics. Contrast pyramid, shift-invariant discrete wavelet transform, and dual-tree complex wavelet transform fusion are applied, as well as levels of JPEG2000 compression. The differing tasks are shown to be more or less appropriate for differentiating among fusion methods, and future directions pertaining to the creation of task-specific metrics are explored.

Assessment of fused videos using scanpaths: a comparison of data analysis methods.

The increased interest in image fusion (combining images of two or more modalities such as infrared and visible light radiation) has led to a need for accurate and reliable image assessment methods. Previous work has often relied upon subjective quality ratings combined with some form of computational metric analysis. However, we have shown in previous work that such methods do not correlate well with how people perform in actual tasks utilising fused images. The current study presents the novel use of an eye-tracking paradigm to record how accurately participants could track an individual in various fused video displays. Participants were asked to track a man in camouflage outfit in various input videos (visible and infrared originals, a fused average of the inputs; and two different wavelet-based fused videos) whilst also carrying out a secondary button-press task. The results were analysed in two ways, once calculating accuracy across the whole video, and by dividing the video into three time sections based on video content. Although the pattern of results depends on the analysis, the accuracy for the inputs was generally found to be significantly worse than that for the fused displays. In conclusion, both approaches have good potential as new fused video assessment methods, depending on what task is carried out.

Turning the other cheek: the viewpoint dependence of facial expression after-effects.

How do we visually encode facial expressions? Is this done by viewpoint-dependent mechanisms representing facial expressions as two-dimensional templates or do we build more complex viewpoint independent three-dimensional representations? Recent facial adaptation techniques offer a powerful way to address these questions. Prolonged viewing of a stimulus (adaptation) changes the perception of subsequently viewed stimuli (an after-effect). Adaptation to a particular attribute is believed to target those neural mechanisms encoding that attribute. We gathered images of facial expressions taken simultaneously from five different viewpoints evenly spread from the three-quarter leftward to the three-quarter rightward facing view. We measured the strength of expression after-effects as a function of the difference between adaptation and test viewpoints. Our data show that, although there is a decrease in after-effect over test viewpoint, there remains a substantial after-effect when adapt and test are at differing three-quarter views. We take these results to indicate that neural systems encoding facial expressions contain a mixture of viewpoint-dependent and viewpoint-independent elements. This accords with evidence from single cell recording studies in macaque and is consonant with a view in which viewpoint-independent expression encoding arises from a combination of view-dependent expression-sensitive responses.

Pulmonary autograft versus homograft replacement of the aortic valve: a prospective randomized trial.

BACKGROUND: Pulmonary autografts offer many theoretical advantages. However, the operation is complex, may interfere with right ventricular and pulmonary outflow function, and requires a longer operative time than does the homograft operation. The effects of these potential disadvantages are unknown. METHODS: To clarify these issues we randomized 70 patients undergoing aortic valve replacement to an aortic homograft group (group A = 37 patients; 53%; 34 male, 3 female) or a pulmonary autograft group (group B = 33 patients; 47%; 28 male, 5 female). Ages varied from 12 to 65 years (mean 39 +/- 15 years) for group A and from 3 to 54 years (mean 29 +/- 15 years) for group B (p = not significant). Eleven patients in group A (30%) and eight in group B (24%) had previous aortic valve surgery. All patients were operated on by the same surgeon. The mean cardiopulmonary bypass time was 113 +/- 29 minutes (range 66 to 175 minutes) for group A and 151 +/- 31 minutes (range 115 to 226 minutes) for group B (p < 0.002). Mean aortic crossclamp time was 85 +/- 19 minutes (range 45 to 140 minutes) for group A and 109 +/- 20 minutes (range 74 to 164 minutes) for group B (p = 0.02). In 32 patients (86.5%) the aortic homograft was implanted as a root with coronary reimplantation. All pulmonary autografts were implanted as a root. RESULTS: No early or late deaths had occurred in this series at a mean follow-up time of 16 months (range 3 to 21 months). Two patients (one in each group) required reexploration for bleeding. No statistically significant differences were observed between the two groups with regard to ventilatory support (group A, mean 10 +/- 8.5 hours; group B, mean 29 +/- 85 hours), total blood loss (group A, mean 471 +/- 347 ml; group B, mean 543 +/- 404 ml), intensive care unit stay (group A, mean 1.2 +/- 0.6 days; group B, mean 2 +/- 3.7 days), and hospital stay (group A, mean 9.5 = 3.2 days; group B, mean 12 +/- 6 days). Postoperatively, all patients are in New York Heart Association class I (93%) or II (7%) (p = not significant). Ejection fraction for the two groups did not change significantly over the follow-up period. Left ventricular mass and diastolic diameter showed progressive regression, with no apparent difference between the two treatment groups to date. Echocardiographic evaluation of aortic valve function at 6 months showed good valve function in all patients with no evidence of aortic regurgitation in 80% of both groups. In group B the right ventricular outflow gradient was below 15 mm Hg over the follow-up period. Holter monitoring, available only in 44 patients (63%), showed most of the arrhythmias to be grade 0 to 1 of the modified Lown grading system. CONCLUSION: Although the pulmonary autograft requires a significantly longer operating time, this does not seem to affect early and medium-term outcome when compared with results obtained with aortic homografts. Continued patient evaluation is warranted, particularly with regard to evidence of valve degeneration and right ventricular function and arrhythmias in the long term.

Anatomic correction of the syndrome of prolapsing right coronary aortic cusp, dilatation of the sinus of Valsalva, and ventricular septal defect.

BACKGROUND: Although the syndrome of ventricular septal defect and aortic regurgitation was described a long time ago, there is still no agreement about the anatomic and functional components of the syndrome and the optimal methods of management. OBJECTIVE: Our objective was to describe a new simple technique of anatomic correction of all the components of the syndrome, based on redefining the salient anatomic and functional features of the syndrome. METHODS: Anatomic correction of the syndrome is achieved through a transaortic approach with the placement of a series of pledget-supported mattress sutures using autogenous pericardium. The sutures are used to close the ventricular septal defect, plicate the aortic sinus, and correct the outward and downward displacement of the anulus of the aortic valve. The technique is designed to correct all the anatomic functional components including severe aortic regurgitation when present. RESULTS: Between 1972 and 1996, 46 patients with this syndrome underwent surgical treatment. The current technique was used in most of the patients operated on before 1981 and in all patients since that date. There were no early or late deaths during a follow-up period varying from 3 months to 24 years (mean 8.4 years). Aortic regurgitation was abolished in 16 and improved in the remaining patients, The hemodynamic results have been maintained except in five patients operated on early in the series, in whom additional procedures on the cusps were performed. CONCLUSIONS: Anatomic correction of all the components of the syndrome of prolapsing right coronary cusp, dilatation of the sinus of Valsalva, and ventricular septal defect, can be achieved by a very simple technique. This technique can be applied in young children and prevents progression and secondary changes. Early correction in all patients with this syndrome is warranted.

Analysis of the T-cell receptor repertoire in human atherosclerosis.

OBJECTIVE: Analysis of T-cell receptor (TCR) beta-chain gene expression in atherosclerotic lesions of human aorta. METHODS: TCR diversity was studied using non-radioactive polymerase chain reaction for quantitative assessment of TCRBV gene transcripts, together with size and sequence analysis of the beta-chain third complementarity-determining region (CDR3). Samples represent a wide range of atheromatous histology, allowing evaluation of the T-cell repertoire at different stages of disease. RESULTS: Diverse TCRBV family usage was observed in the majority of the samples, as the 25 different TCRBV products were detected at levels exceeding background. The data also showed that TCRBV transcripts expressed in the diseased aorta tissue displayed considerable size heterogeneity and no repetition of CDR3 nucleotide motifs. CONCLUSIONS: The early presence of T-lymphocytes in the atheromatous blood vessel has been interpreted as an indication of specific immunological reactions operating during the course of the atherosclerotic process. Although a T-cell infiltrate characterized by limited usage of TCRAV genes cannot be excluded the unrestricted usage of TCRBV genes argues against a local T-cell clonal expansion in atherogenesis.

The influence of total knee arthroplasty on lower limb blood flow.

Ischaemic complications of total knee arthroplasty (TKA) are unusual and tend to occur in patients with peripheral vascular disease (PVD). A prospective study was undertaken to investigate the effect of TKA on blood flow in patients without clinical evidence of PVD. Ankle brachial index (ABI) did not alter post-operatively and no changes in arterial waveforms were found. Unless there is clinical evidence of PVD, TKA under tourniquet control is therefore very unlikely to cause ischaemic complications.

Basic fibroblast growth factor upregulates the expression of vascular endothelial growth factor in vascular smooth muscle cells. Synergistic interaction with hypoxia.

BACKGROUND: Vascular endothelial growth factor (VEGF) is a hypoxia-inducible direct angiogenic factor. Upregulation of VEGF is thought to mediate many of the angiogenic effects of growth factors that are not direct endothelial cell mitogens. Like VEGF, basic fibroblast growth factor (bFGF) is considered to induce angiogenesis by a direct effect on endothelial cells. This study investigated the possibility that bFGF may also act indirectly by regulating VEGF expression in vascular smooth muscle cells (VSMCs). METHODS AND RESULTS: Incubation of confluent and quiescent cultures of rabbit VSMCs with bFGF caused a time- and concentration-dependent increase in steady-state levels of VEGF mRNA, as analyzed by Northern blot hybridization. Exposure of VSMCs to a threshold hypoxic stimulus (2.5% O2) caused a modest increase in VEGF mRNA levels. However, the combination of 2.5% O2 with bFGF had a marked synergistic effect. This effect was specific for VEGF as hypoxia did not enhance bFGF-induced expression of the proto-oncogene c-myc. Synergistic upregulation of VEGF mRNA expression also was observed between hypoxia and TGF-beta 1. CONCLUSIONS: These results suggest that bFGF may promote angiogenesis both by a direct effect on endothelial cells and also indirectly by the upregulation of VEGF in VSMCs. The synergy demonstrated between hypoxia and either bFGF or TGF-beta 1 suggests that multiple diverse stimuli may interact via the upregulation of VEGF expression in VSMCs to amplify the angiogenic response.

Hypoxia and platelet-derived growth factor-BB synergistically upregulate the expression of vascular endothelial growth factor in vascular smooth muscle cells.

Vascular endothelial growth factor (VEGF) mRNA expression was analysed in rabbit vascular smooth muscle cells following exposure to hypoxia and platelet-derived growth factor-BB (PDGF-BB). Hypoxia potently upregulated VEGF mRNA steady-state levels in a time- and concentration-dependent manner reaching a maximum level (approximately 30-fold increase) after 12-24 h at 0% 0(2). In contrast, PDGF-BB caused a modest increase in VEGF expression. However, the combination of PDGF-BB and a threshold hypoxic stimulus (2.5% O2 for 4 h) had a marked synergistic effect. Synergy between hypoxia and PDGF-BB was selective for VEGF expression as hypoxia had no effect on the PDGF-induced upregulation of the proto-oncogene c-myc. These results raise the possibility that hypoxia and PDGF-BB may act in concert to induce VEGF expression in the arterial wall during the development of atherosclerosis.

The adventitia and atherogenesis: removal initiates intimal proliferation in the rabbit which regresses on generation of a 'neoadventitia'.

Removal of the carotid artery adventitia from rabbits induced the formation of an intimal hyperplastic lesion. In rabbits fed a normal diet, the lesion (measured as the intimal:medial ratio) was maximal by day 14 (0.456 +/- 0.079, n = 5, P < 0.01) and thereafter, regressed towards control dimensions (0.037 +/- 0.003, n = 14) by day 28 (0.080 +/- 0.025, n = 7, P = 0.14). In rabbits fed a high cholesterol diet, the lesion was again maximal by day 14 (0.376 +/- 0.056, n = 8, P < 0.01). Although some regression was seen, the lesion persisted to day 42 (0.272 +/- 0.052, n = 8, P < 0.01). Electron microscopy and immunocytochemistry showed two types of lesion, (a) smooth muscle cell predominant on normal diet and, (b) macrophage predominant on high cholesterol diet. Smooth muscle cell predominant lesions underwent almost complete regression, whereas macrophage predominant lesions persisted. We propose that lesion formation may be initiated following the development of arterial wall hypoxia, secondary to excision of the adventitial vasa vasorum. Furthermore, we have devised a novel method to restore a highly vascular 'neoadventitia' to an artery whose adventitia has previously been removed, using loosely placed PVC tubing. We suggest this 'neoadventitia' was able to inhibit the formation of an intimal hyperplastic lesion and to promote regression of an already established lesion by restoring arterial wall oxygenation.

Somatostatinoma of the pancreas with hypercalcaemia. A case report.

A unique case of somatostatinoma of the pancreas complicated by severe hypercalcaemia is described. Surgical resection was not possible owing to tumour extent. A dramatic and prolonged clinical and biochemical response was achieved with streptozotocin.

[Identification of the risk factors for morbidity from the most common diseases as part of the primary health care for the personnel of industrial enterprises]. / Identificarea factorilor cu risc de îmbolnavire la boli mai frecvente, în cadrul îngrijirilor primare de sanatate pentru personalul unei întreprinderi.

The investigations were performed in a building enterprise with 7,500 workers with a mean age of 37 years, mainly males. It aimed at identifying the risk factors for the common diseases. The knowledge of these factors should be considered when elaborating the health programmes intended to prevent the frequent diseases (traumas, respiratory locomotor and digestive diseases).