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PubMed2003

The effect of fatty infiltration on the liver tissue enhancement during portal phase computed tomography.

RATIONALE AND OBJECTIVES: To correlate the presence of fatty liver and the enhancement value of liver tissue during portal phase computed tomography. MATERIALS AND METHODS: Liver tissue enhancements during portal phase computed tomography were measured in 16 fatty liver and 35 control patients. All patients intravenously received 100 mL of non-ionic contrast material (320 mg iodine/ mL) at a rate of 3 mL/second, and the image acquisition started at 70 seconds. Attenuation values were measured on the 80-second portal phase images and the corresponding unenhanced images, and the contrast enhancement value (HU) of the liver tissue was calculated. Adjusted enhancement values were also calculated with the following equation: adjusted enhancement value = enhancement value (HU)/[dose (grams of iodine)/body weight (kg)]. RESULTS: The contrast enhancement value was significantly reduced in the fatty liver patients compared with the normal controls (37.0 +/- 7.2 vs 49.8 +/- 12.0 HU; P < .0001). This difference was still significant in adjusted enhancement value (80.1 +/- 13.7 vs 93.6 +/- 23.0 HU kg g(-1); P = .01). CONCLUSION: The liver tissue with fatty infiltration was less enhanced than controls, probably because of decreased portal perfusion.

Case-Control Studies↗

PubMed2003

Comparison of contrast-enhanced harmonic ultrasonography and power Doppler ultrasonography for depicting vascularity of hepatocellular carcinoma identified by angiography-assisted CT.

The sensitivity of contrast-enhanced harmonic gray scale imaging was compared with that of power Doppler sonography in depicting tumor vascularity and contrast enhancement of hepatocellular carcinoma (HCC) identified by angiography-assisted computed tomography (CT). One hundred thirty-nine classic HCC nodules (108 patients), each appearing as a high-attenuation mass on early-phase CT during hepatic arteriography and as a perfusion defect on CT during arterial portography, were evaluated. Vascular findings and contrast enhancement patterns were evaluated by contrast-enhanced harmonic gray scale imaging. Arterial pulsatile flow into each nodule was checked by power Doppler sonography. Sensitivity of each modality for depicting tumor vascularity was examined by angiography-assisted CT findings as the gold standard. The sensitivity of contrast-enhanced harmonic gray scale imaging (134/139, 96.4%) was significantly greater than that of power Doppler sonography (96/139, 69.1%) (P<0.05). Twenty-six of twenty-seven nodules (96.3%) in the lateral segment, in which motion artifact is likely, were enhanced by contrast-enhanced harmonic gray scale imaging. Contrast-enhanced harmonic gray scale imaging is more sensitive than power Doppler sonography and is a noninvasive method that can be used as effectively as angiography-assisted CT to evaluate tumor vessels and contrast enhancement of HCC.

Journal Article↗

PubMed2006

Pyridine-Ag20 cluster: a model system for studying surface-enhanced Raman scattering.

This work presents a detailed analysis of enhanced Raman scattering of the pyridine-Ag(20) model system using time-dependent density functional theory. A consistent treatment of both the chemical and electromagnetic enhancements (EM) is achieved by employing a recently developed approach based on a short-time approximation for the Raman cross section. A strong dependence of the absolute and relative intensities on the binding site and excitation wavelength is found. The analysis of the Raman scattering cross sections shows the importance of different contributions to the enhancements, including static chemical enhancements (factor of 10), charge-transfer enhancements (10(3)), and EM enhancements (10(5)). The largest enhancement found (10(5)-10(6)) is due to the EM mechanism, with a small contribution from the chemical interaction. This suggests that the enhanced Raman scattering due to atomic clusters is comparable to findings on single nanoparticles. A combination of information about the vibrational motion and the local chemical environment provides a simple picture of why certain normal modes are enhanced more than others.

Journal Article↗

PubMed1996

Synergistic effects of chemical enhancers and therapeutic ultrasound on transdermal drug delivery.

The effects of (i) a series of chemical enhancers and (ii) the combination of these enhancers and therapeutic ultrasound (1 MHz, 1.4 W/cm2, continuous) on transdermal drug transport are investigated. A series of chemical enhancer formulations, including (i) polyethylene glycol 200 dilaurate (PEG), (ii) isopropyl myristate (IM), (iii) glycerol trioleate (GT), (iv) ethanol/pH 7.4 phosphate buffered saline in a 1:1 ratio (50% EtOH), (v) 50% EtOH saturated with linoleic acid (LA/EtOH), and (vi) phosphate buffered saline (PBS), as a control, are evaluated using corticosterone as a model drug. LA/EtOH is the most effective of these enhancers, increasing the corticosterone flux by 900-fold compared to that from PBS. Therapeutic ultrasound (1 MHz, 1.4 W/cm2, continuous) increases the corticosterone permeability from all of the enhancers examined by up to 14-fold (LA/EtOH) and increases the corticosterone flux from the saturated solutions by up to 13,000-fold (LA/EtOH), relative to that from PBS. Similar enhancements are obtained with LA/EtOH with and without ultrasound for four other model drugs, dexamethasone, estradiol, lidocaine, and testosterone. The permeability enhancements for all of these drugs resulting from the addition of linoleic acid to 50% EtOH increase with increasing drug molecular weight. Likewise, the permeability enhancement attained by ultrasound and LA/EtOH relative to passive EtOH exhibits a similar size dependence. A mechanistic explanation of this size dependence is provided. It is suggested that bilayer disordering agents, such as linoleic acid and ultrasound, transform the SC lipid bilayers into a fluid lipid bilayer phase or create a separate bulk oil phase. The difference in diffusivity of a given solute in SC bilayers and in either fluid bilayers or bulk oil is larger for larger solutes, thereby producing greater enhancements for larger solutes.

Administration, Cutaneous↗

PubMed2002

Transdermal delivery of highly lipophilic drugs: in vitro fluxes of antiestrogens, permeation enhancers, and solvents from liquid formulations.

PURPOSE: Highly lipophilic basic drugs, the antiestrogens AE 1 (log P = 5.82) and AE 2 (log P = 7.8) shall be delivered transdermally. METHODS: Transdermal permeation of drugs, enhancers, and solvents from various fluid formulations were characterized by in-vitro permeation studies through excised skin of hairless mice. Furthermore, differential scanning calorimetry (DSC) measurements of skin lipid phase transition temperatures were conducted. RESULTS: Transdermal flux of highly lipophilic drugs was extraordinarily enhanced by the unique permeation enhancer combination propylene glycol-lauric acid (9 + 1): steady-state fluxes of AE 1 and AE 2 were as high as 5.8 microg x cm(-2) x h(-1) and 3.2 microg x cm(-2) x h(-1), respectively. This dual enhancer formulation also resulted in a marked increase in the transdermal fluxes of the enhancers. Furthermore, skin lipid phase transition temperatures were significantly reduced by treatment with this formulation. CONCLUSION: Transdermal delivery of highly lipophilic drugs can be realized by using the permeation enhancer combination propylene glycol-lauric acid. The extraordinary permeation enhancement for highly lipophilic drugs by this formulation is due to mutual permeation enhancement of these two enhancers and their synergistic lipid-fluidising activity in the stratum corneum.

Adjuvants, Pharmaceutic↗

PubMed2000

Clinical evaluation of 'local contrast enhancement' for oral fluorescein angiograms.

PURPOSE: To describe and assess the clinical impact of 'local contrast enhancement' on oral fluorescein angiograms. METHODS: Oral fluorescein angiograms (OFA) were performed on 12 patients with a range of diabetic retinopathy. The digital images were processed using two enhancement techniques: histogram equalization, a widely available method; and 'local contrast enhancement'. Twelve control images and 24 enhanced images were randomised and subjectively graded for clarity between 1 and 100 on a visual analogue scale by two masked observers. A score of 50% was chosen as the cut-off for clinically useful images. RESULTS: The mean score for the unenhanced images was 38.8% (SD 19.4); the histogram equalization performed better at 54.7% (SD 10.0) (p = 0.016) and 'local contrast enhancement' at 69.4% (SD 13.6) (p < 0.001). These results equate to a 14.7% improvement in comparison with histogram equalization and a 30.3% improvement with the 'local contrast enhancement' technique. All the 'local contrast enhancement' images were clinically useful, compared with 58.3% of the histogram equalization images (chi 2 2.08, p = 0.2), and 33.3% of the control images (chi 2 = 6.75, p = 0.01). CONCLUSION: This pilot study has demonstrated the power of 'local contrast enhancement' techniques for low-contrast fluorescein angiograms. Using 'local contrast enhancement' oral fluorescein angiograms can give high-quality images and may allow safer patient investigation.

Administration, Oral↗

PubMed1998

Lipopolysaccharide enhances neurogenic plasma exudation in guinea-pig airways.

1. Lipopolysaccharide (LPS) is implicated in many pulmonary and airway inflammatory diseases. Tachykinins released from nerve endings increase vascular permeability. In this study, we have assessed the enhancement by LPS of tachykinin-mediated plasma exudation in guinea-pig airways, and examined the role of oxidants as well as leukocyte adherence. 2. LPS (100 microg kg(-1), i.v.) was administered 0-3 h before bilateral electrical stimulation of the cervical vagus nerves in animals anaesthetized with urethane and ventilated. Vagal stimulation increased vascular permeability in the airways. LPS enhanced the vagally-mediated plasma exudation with the peak effect at 1 h after LPS administration. LPS alone induced no significant plasma exudation. LPS also enhanced exogenous substance P (10(-8) mol kg(-1), i.v.)-induced plasma exudation. 3. The NK-1 receptor antagonist L-732,138 abolished vagally-induced plasma exudation and significantly inhibited the enhancement by LPS. Pretreatment with superoxide dismutase (SOD, 5000 U kg(-1), i.p.) did not affect the vagally-induced plasma exudation, but inhibited the LPS-enhanced neurogenic plasma leakage. The LPS-enhanced vagally-induced plasma exudation was not completely inhibited by either L-732,138 or SOD pretreatment alone, but was blocked by the combination of both pretreatments. 4. Neutrophil depletion by cyclophosphamide alone did not influence vagally-induced plasma exudation, but significantly inhibited the LPS-enhanced response. 5. In conclusion, we have demonstrated LPS enhanced neurogenic plasma exudation by augmenting the response to tachykinins, partly through NK-1 receptors, to directly increase vascular permeability or to enhance leukocyte adhesion-mediated endothelial cell injury. Tachykinins released from nerve endings may contribute to endotoxin-related airway inflammatory responses.

Animals↗

PubMed2002

Complexities in ETS-domain transcription factor function and regulation: lessons from the TCF (ternary complex factor) subfamily. The Colworth Medal Lecture.

The ETS-domain transcription factor family can be divided into a series of subfamilies. Elk-1 represents the founding member of the ternary complex factor (TCF) subfamily. By focusing on the TCF subfamily, we can demonstrate the complexities that exist in the function and regulation of ETS-domain transcription factors. This article focuses on Elk-1 in detail and summarizes the functions of other TCFs. The key themes covered include the domain structure of the TCFs, the mechanisms of complex formation with serum response factor, regulation of TCFs by mitogen-activated protein kinase cascades, and transcriptional regulatory properties of the TCFs. Finally, the emerging role of the TCFs in vivo is discussed. A picture is developing indicating that, while these proteins exhibit significant sequence and functional conservation, key differences in their structure and regulation are being identified which may relate to unique functions of these proteins in vivo.

Amino Acid Sequence↗

PubMed2000

Glucocorticoid enhancement of memory consolidation in the rat is blocked by muscarinic receptor antagonism in the basolateral amygdala.

Glucocorticoid-induced memory enhancement is known to depend on beta-adrenoceptor activation in the basolateral amygdala (BLA). Additionally, inactivation of muscarinic cholinergic receptors in the rat amygdala blocks memory enhancement induced by concurrent beta-adrenergic activation. Together, these findings suggest that glucocorticoid-induced modulation of memory consolidation requires cholinergic as well as adrenergic activation in the BLA. Two experiments investigated this issue. The first experiment examined whether blockade of muscarinic cholinergic receptors in the BLA with atropine alters the memory-enhancing effects of the systemically administered glucocorticoid dexamethasone. Dexamethasone (0.3, 1.0 or 3.0 mg/kg, s.c.) administered to rats immediately after inhibitory avoidance training produced dose-dependent enhancement of 48-h retention. Concurrent bilateral infusions of the muscarinic cholinergic antagonist atropine (0.5 microg in 0.2 microL per side) into the BLA blocked the memory enhancement. The second experiment investigated whether the BLA is a locus of interaction between glucocorticoid and muscarinic activation. The specific glucocorticoid receptor (GR or type II) agonist RU 28362 (1.0, 3.0 or 10 ng) was infused into the BLA either alone or together with atropine immediately after training. The GR agonist produced dose-dependent memory enhancement and atropine blocked the memory enhancement. These findings indicate that muscarinic cholinergic activation within the BLA is critical for enabling glucocorticoid enhancement of memory consolidation and that enhancement of memory induced by GR activation in the BLA requires cholinergic activation within the BLA.

Acetylcholine↗

PubMed1999

Magnetic resonance outcome of new enhancing lesions in patients with relapsing-remitting multiple sclerosis.

The aim of the study was to monitor the natural history of new enhancing lesions in multiple sclerosis (MS) by means of serial gadolinium-enhanced magnetic resonance imaging (MRI). Out of the 63 new enhancing lesions seen on the baseline scan, belonging to 26 relapsing-remitting MS patients, 26 (40%), nine (14%) and four (6%) lesions showed persisting enhancement at first, second and third follow-up scan, respectively. At the end of 5 months of follow-up, 58 (92%) of the new enhancing lesions were detected as T2 hyperintensities, 24 (38%) as T1 hypointensities ('black holes'), and five lesions (8%) disappeared in both T2 and T1 weighted images. Duration of gadolinium enhancement of at least two consecutive scans significantly influenced the development of 'black holes'. No significant correlation was observed between volume, location, configuration of enhancement at baseline and final outcome of the lesion. In individual cases, different evolution of new enhancing lesions was observed at the same time. In conclusion, this study documented that different outcomes of new lesions are unrelated either to the individual patient or to the baseline MRI characteristics. However, prolonged blood-brain-barrier disruption as shown by persisting enhancement significantly influences the lesion outcome.

Adolescent↗

PubMed2001

Facial nerve palsy: evaluation by contrast-enhanced MR imaging.

AIM: The purpose of this study was to investigate the value of contrast-enhanced magnetic resonance (MR) imaging in patients with peripheral facial nerve palsy. MATERIALS AND METHODS: MR imaging was performed in 147 patients with facial nerve palsy, using a 1.0 T unit. All of 147 patients were evaluated by contrast-enhanced MR imaging and the pattern of enhancement was compared with that in 300 control subjects evaluated for suspected acoustic neurinoma. RESULTS: The intrameatal and labyrinthine segments of the normal facial nerve did not show enhancement, whereas enhancement of the distal intrameatal segment and the labyrinthine segment was respectively found in 67% and 43% of patients with Bell's palsy. The geniculate ganglion or the tympanic-mastoid segment was enhanced in 21% of normal controls versus 91% of patients with Bell's palsy. Abnormal enhancement of the non-paralyzed facial nerve was found in a patient with bilateral temporal bone fracture. CONCLUSION: Enhancement of the distal intrameatal and labyrinthine segments is specific for facial nerve palsy. Contrast-enhanced MR imaging can reveal inflammatory facial nerve lesions and traumatic nerve injury, including clinically silent damage in trauma.

Adolescent↗

PubMed2002

Comparative follow-up of enhancement phenomena with MRI and Proton MR Spectroscopic Imaging after intralesional immunotherapy in glioblastoma--Report of two exceptional cases.

The morphologic pattern of contrast enhancement in magnetic resonance imaging (MRI) of glioblastoma patients could be non specific and metabolic investigations can be useful for the differentiation of tumorous and non tumorous enhancement. Following initial therapy secondary tissue changes can occur and non specific non tumorous enhancement phenomena have been observed after local immuno- and gene therapy strategies. Magnetic resonance spectroscopic imaging (MRSI) has the potential to give more specific information on the metabolism of the suspective tissue and to differentiate enhancing phenomena. We demonstrate two cases of patients suffering from a glioblastoma with simultaneous MRI and MRSI follow-up after multimodal treatment with surgery, radiation, intralesional immunotherapy (IL-4 toxin) and ongoing chemotherapy. MRI demonstrated extensive and increasing enhancement. This was highly suspicious of rapid progressive local tumor recurrency in both patients. Simultaneously obtained MRSI did not show the expected result of extensive and increasing choline concentration within these enhancing areas. This indicated that the enhancement did most likely not reflect vital tumor tissue. Chemotherapy treatment was continued and further MRI follow up revealed nearly complete regression of all enhancement. In pretreated glioblastoma metabolic data of MRSI seem to be potentially helpful to differentiate tumorous and non tumorous enhancement phenomena after local immunotherapy, which might be useful for further treatment decisions.

Adult↗

PubMed2004

Multi-detector row CT: effect of iodine dose reduction on hepatic and vascular enhancement.

PURPOSE: To evaluate the impact of different iodine concentrations of intravenous contrast agent on hepatic and vascular enhancement during arterial and porto-venous phase imaging using a 4-channel multi-detector row CT (MDCT). MATERIAL AND METHODS: One hundred consecutive patients referred for triphasic abdominal MDCT were randomly assigned into four groups receiving different iodine concentration (200, 250, 300 or 350 mg/ml). Non-contrast, arterial, and porto-venous phase 4-channel MDCT imaging was performed (VolumeZoom, Siemens, Germany). A fixed volume of 150 ml intravenous contrast agent at a rate of 3 ml/s was injected using an automatic bolus-tracking system (Care Bolus, Siemens, Erlangen). Hepatic and vascular enhancement values were measured over time and non-contrast values were subtracted in order to compute arterial and porto-venous mean hepatic (MHE) and mean aortic (MAE) enhancement for each group. Mean change of enhancement > 80 HU for the aorta and > 40 HU for the liver during porto-venous phase imaging was considered as sufficient enhancement. RESULTS: All groups achieved sufficient vascular enhancement during arterial phase imaging; MAE with 350 mg/ml (222 HU) and 300 mg/ml (213HU) was significantly better than with 250 mg (196HU) and 200 mg/ml (169 HU), whereas MHE showed no statistically significant difference between the groups (range 16 - 25 HU). Porto-venous MHE showed increased enhancement with larger concentrations, with significant differences among the groups. Only the higher concentration groups (350 mg/ml und 300 mg/ml) fulfilled in every individual the guidelines for sufficient porto-venous MHE. In the lower concentration groups, 8 patients with 200 mg/ml and 3 patients with 250 mg/ml showed enhancement values below the required minimum. CONCLUSION: A decrease in iodine contrast agent down to 200 mg/ml concentration is only tenable for propose of vascular aortic and hepatic arterial enhancement, whereas hepatic porto-venous phase imaging still requires concentrations at or above the level of 300 mg/ml.

Adult↗

PubMed2005

Contrast-enhanced sonography for the characterisation of hepatocellular carcinomas--correlation with histological differentiation.

AIM: We aimed to characterise the vascularisation patterns of hepatocellular carcinomas in contrast-enhanced sonography in correlation to the histological differentiation of hepatocellular carcinomas (HCC), and we also compared the diagnostic value of contrast-enhanced sonography in addition to B-scan sonography and power Doppler sonography. METHODS: 51 hepatocellular carcinomas (21 well differentiated, 27 moderately differentiated, 3 poorly differentiated) were examined: by B-scan sonography, power Doppler sonography and contrast-enhanced sonography using phase or pulse inversion harmonic imaging with a low mechanical index (< 0.3) and second generation microbubble contrast medium (Optison, Sonovue) as echo-enhancing agent. Lesion vascularity and the kinetics of contrast enhancement within the lesions in the early arterial phase, arterial phase, portal phase and late phase were analysed. The final diagnosis of a HCC was assessed after B-scan sonography, power Doppler sonography and contrast-enhanced sonography. RESULTS: Hypervascularisation and/or irregular tumour vascularisation could be detected in 18/48 HCCs (37.5%) by power Doppler sonography. After contrast application, 46/51 HCCs (90.2%) were identified as hyperechoic lesions during the early arterial or arterial phase with no correlation to histological differentiation. In the portal phase and late phase, the echogenicity of HCCs after contrast application was variable. A hypoechoic appearance was noted in 17/51 HCCs (33.3%) in the portal phase and in 21/51 HCCs (41.2%) in the late phase. Moderately differentiated HCCs were more often hypoechoic than well differentiated HCCs (p = 0.04). CONCLUSION: Contrast-enhanced sonography is highly efficient for the detection of tumour vascularity in HCCs. The majority of HCCs--regardless of histological differentiation--can be characterised as hypervascular lesions in the early arterial and arterial phase with irregular tumour vessels using contrast-enhanced sonography. In addition to B-scan sonomorphology, contrast-enhanced sonography may offer helpful information in patients with liver cirrhosis and focal liver lesions.

Carcinoma, Hepatocellular↗

PubMed1987

Identification of a cell-specific transcriptional enhancer in the first intron of the mouse alpha 2 (type I) collagen gene.

A transcriptional enhancer has been identified in the first intron of the mouse alpha 2 (type I) collagen gene in a region between +418 and +1524 base pairs from the transcriptional start site. The enhancer functions both when it is located 5' and 3' to the promoter that it activates and is independent of the orientation of the element. The enhancer stimulates both the homologous alpha 2 type I [alpha 2(I)] collagen promoter and the heterologous early simian virus 40 promoter. In transient expression experiments, enhancer-dependent transcription from the alpha 2(I) collagen promoter utilizes the same transcriptional start site as the one used in the endogenous alpha 2(I) collagen gene. The enhancer activates transcription at a distance of at least 3 kilobase pairs from the transcriptional start site. The alpha 2(I) collagen enhancer displays cell specificity, since it is functional in NIH 3T3 fibroblasts but completely inactive in a lymphoid cell line, in contrast to two immunoglobulin gene enhancers that show the opposite behavior. We find several areas of sequence homology with viral enhancers, particularly the enhancer of simian virus 40.

Acetyltransferases↗

PubMed1989

Antibody-dependent enhancement of human immunodeficiency virus type 1 (HIV-1) infection in vitro by serum from HIV-1-infected and passively immunized chimpanzees.

Based on recent reports of antibody-dependent enhancement of human immunodeficiency virus type 1 (HIV-1) infection in vitro by serum from HIV-1-infected humans, sera from HIV-1 antibody-positive chimpanzees (Pan troglodytes) was evaluated for enhancing activity in an in vitro infection assay that uses MT-2 cells (a human lymphoblastoid cell line). Although fresh chimpanzee serum was found to have pronounced infection-enhancing properties in the absence of antibody to HIV-1, this effect was abolished by heat inactivation (57 degrees C, 1 hr) or treatment with cobra venom anticomplementary protein. Heat-inactivated, HIV-1 antibody-positive chimpanzee serum could enhance HIV-1 infection of MT-2 cells in vitro when combined with fresh, normal human serum. By serial serum samples from three HIV-1-infected chimpanzees, HIV-1 antibody-positive chimpanzees are shown to develop enhancing antibodies early in infection (2 mo postchallenge), whereas neutralizing antibodies develop later. Over the course of HIV-1 infection, this enhancing activity decreases while neutralizing activity increases, suggesting a possible role for enhancing and neutralizing activities in HIV-1 pathogenesis. The enhancing activity of an IgG fraction used to passively immunize chimpanzees against HIV-1 infection is shown to be present at dilutions as high as 1:65,000, offering an interesting possible reason for the failure of passive immunization to protect chimpanzees from HIV infection. These results suggest that serum from HIV-1-immunized chimpanzees might be tested to determine whether current HIV-1 candidate vaccines induce production of antibodies that mediate antibody-dependent enhancement of HIV-1 infection in this in vitro assay.

Acquired Immunodeficiency Syndrome↗

PubMed2004

CT-based evaluation of axillary sentinel lymph node status in breast cancer: value of added contrast-enhanced study.

PURPOSE: To evaluate the diagnostic reliability of CT-based sentinel lymph node (SLN) size criteria for selecting the candidates for direct axillary dissection without SLN biopsy and to determine the value of added contrast-enhanced study. MATERIAL AND METHODS: Breast cancer patients (n = 107) underwent triple phasic (1-min, 3-min, 8-min) contrast-enhanced 5 mm-computed tomography (CT) of the breasts and axillae. In the CT image, the most inferior lymph node in the axilla was designated the SLN. Axillary status was judged based on SLN size criteria. CT density, enhancement rate, and peak enhancement time of each SLN were correlated with histopathological results. RESULTS: SLN size criteria demonstrated a sensitivity of 76% and a positive predictive value of 95% in predicting SLN metastasis. The density values at each scanning time-point were significantly different for metastatic and non-metastatic SLN. However, their enhancement rates differed significantly only at 1 min. Their peak enhancement occurred primarily at 1 min. The use of contrast-enhancement criteria improved the predictive sensitivity, but failed to decrease the false-positive rate of the SLN size criteria. CONCLUSION: The enhancement rate at 1 min proved to be the most useful parameter in contrast-enhanced CT studies; however, it failed in improving the accuracy of the SLN size criteria.

Adult↗

PubMed2000

The effects of a computer skill training programme adopting social comparison and self-efficacy enhancement strategies on self-concept and skill outcome in trainees with physical disabilities.

PURPOSE: The aim of this controlled, quasi-experimental study was to evaluate the effects of both self-efficacy enhancement and social comparison training strategy on computer skills learning and self-concept outcome of trainees with physical disabilities. METHOD: The self-efficacy enhancement group comprised 16 trainees, the tutorial training group comprised 15 trainees, and there were 25 subjects in the control group. Both the self-efficacy enhancement group and the tutorial training group received a 15 week computer skills training course, including generic Chinese computer operation, Chinese word processing and Chinese desktop publishing skills. The self-efficacy enhancement group received training with tutorial instructions that incorporated self-efficacy enhancement strategies and experienced self-enhancing social comparisons. The tutorial training group received behavioural learning-based tutorials only, and the control group did not receive any training. The following measurements were employed to evaluate the outcomes: the Self-Concept Questionnaire for the Physically Disabled Hong Kong Chinese (SCQPD), the computer self-efficacy rating scale and the computer performance rating scale. RESULTS: The self-efficacy enhancement group showed significantly better computer skills learning outcome, total self-concept, and social self-concept than the tutorial training group. The self-efficacy enhancement group did not show significant changes in their computer self-efficacy: however, the tutorial training group showed a significant lowering of their computer self-efficacy. CONCLUSIONS: The training strategy that incorporated self-efficacy enhancement and positive social comparison experiences maintained the computer self-efficacy of trainees with physical disabilities. This strategy was more effective in improving the learning outcome (p = 0.01) and self-concept (p = 0.05) of the trainees than the conventional tutorial-based training strategy.

Adult↗