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1.
Orthod Craniofac Res ; 27(1): 110-117, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37501526

ABSTRACT

BACKGROUND: A longitudinal cohort study was established to investigate the well-being of children born with cleft lip and/or palate (CL/P) during the COVID-19 pandemic, in Victoria, Australia. MATERIALS AND METHODS: The Royal Children's Hospital cleft service database was used to identify children aged between 4 and 17 years old born with an isolated CL/P. Families of eligible children who consented to participate were asked to complete the Strengths and Difficulties Questionnaire (SDQ) between October and December 2020 and again 6-month later. SDQ results from typically developing Australian children during the COVID-19 pandemic were utilized from a previously published study. RESULTS: 63 parents completed the baseline questionnaire, with 44 completing the 6-month follow-up. For participants at baseline, the mean age was 8.9 years, with 55% male. All outcome domains of the SDQ improved between baseline and timepoint 2, with the difference in total difficulties scores being statistically significant, indicating a reduction in total difficulties at timepoint 2, associated with the easing of COVID-19 restrictions. When compared with the Australian population during the COVID-19 pandemic, Victorian children born with CL/P had lower SDQ scores for all difficulties outcome domains, with statistically significant results for conduct problems, hyperactivity, peer problems and total difficulties, indicating fewer difficulties for children born with CL/P. CONCLUSIONS: Children born with CL/P experienced fewer difficulties when compared with the typically developing Australian population during the COVID-19 pandemic. The level of restrictions imposed because of the pandemic also had little influence on the well-being of these children.


Subject(s)
COVID-19 , Cleft Lip , Cleft Palate , Child , Humans , Male , Child, Preschool , Adolescent , Female , Cleft Lip/epidemiology , Cleft Palate/epidemiology , Longitudinal Studies , Pandemics , Australia/epidemiology , COVID-19/epidemiology
2.
Int J Pharm ; 568: 118496, 2019 Sep 10.
Article in English | MEDLINE | ID: mdl-31279053

ABSTRACT

Magnetic resonance angiography (MRA) requires the use of contrast agents (CAs) to enable accurate diagnosis. There are currently no CAs on the market with appropriate pharmacokinetic (PK) parameters, namely long persistence in the blood, that can be easily used for MRA. We have recently synthesized amphiphilic building blocks loaded with gadolinium (Gd), which self-assemble into Gd-micelles in aqueous media, and have evaluated their potential as a blood-pool contrast agent (BPCA) in vivo. To assess the short and long term PK of Gd-micelles, the blood and organs of the mice were analyzed at t = 30 min, 1, 2, 3 h, 7, 14 and 21 days. Gd-DOTA was used as a control because it is the gold-standard CA for MRA despite its rapid clearance from the blood compartment. Gd-micelles circulated in the blood for more than 3 h postinjection whereas Gd-DOTA was eliminated less than half an hour postinjection. No side effects were observed in the mice up to the end of the study at 21 days and no accumulation of Gd was observed in the brain or bones. The Magnetic Resonance Imaging (MRI) parameters and the results of this in vivo study indicate the true BCPA properties of Gd-micelles and warrant further development.


Subject(s)
Contrast Media/pharmacokinetics , Gadolinium/pharmacokinetics , Heterocyclic Compounds/pharmacokinetics , Micelles , Organometallic Compounds/pharmacokinetics , Animals , Cell Survival/drug effects , Contrast Media/administration & dosage , Gadolinium/administration & dosage , Heterocyclic Compounds/administration & dosage , Humans , MCF-7 Cells , Magnetic Resonance Imaging , Male , Mice, Inbred BALB C , Organometallic Compounds/administration & dosage , Tissue Distribution
3.
Bone Joint Res ; 8(1): 11-18, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30800295

ABSTRACT

OBJECTIVES: Tranexamic acid (TXA) is an anti-fibrinolytic medication commonly used to reduce perioperative bleeding. Increasingly, topical administration as an intra-articular injection or perioperative wash is being administered during surgery. Adult soft tissues have a poor regenerative capacity and therefore damage to these tissues can be harmful to the patient. This study investigated the effects of TXA on human periarticular tissues and primary cell cultures using clinically relevant concentrations. METHODS: Tendon, synovium, and cartilage obtained from routine orthopaedic surgeries were used for ex vivo and in vitro studies using various concentrations of TXA. The in vitro effect of TXA on primary cultured tenocytes, fibroblast-like synoviocytes, and chondrocytes was investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability assays, fluorescent microscopy, and multi-protein apoptotic arrays for cell death. RESULTS: There was a significant (p < 0.01) increase in cell death within all tissue explants treated with 100 mg/ml TXA. MTT assays revealed a significant (p < 0.05) decrease in cell viability in all tissues following treatment with 50 mg/ml or 100 mg/ml of TXA within four hours. There was a significant (p < 0.05) increase in cell apoptosis after one hour of exposure to TXA (100 mg/ml) in all tissues. CONCLUSION: The current study demonstrates that TXA caused significant periarticular tissue toxicity ex vivo and in vitro at commonly used clinical concentrations.Cite this article: M. McLean, K. McCall, I. D. M. Smith, M. Blyth, S. M. Kitson, L. A. N. Crowe, W. J. Leach, B. P. Rooney, S. J. Spencer, M. Mullen, J. L. Campton, I. B. McInnes, M. Akbar, N. L. Millar. Tranexamic acid toxicity in human periarticular tissues. Bone Joint Res 2019;8:11-18. DOI: 10.1302/2046-3758.81.BJR-2018-0181.R1.

4.
J Fish Biol ; 92(5): 1371-1384, 2018 May.
Article in English | MEDLINE | ID: mdl-29516502

ABSTRACT

Cetorhinus maximus aggregations recorded during extensive aerial survey efforts off the north-eastern United States between 1980 and 2013 included aggregations centring on sightings with group sizes of at least 30 individuals. These aggregations occurred in summer and autumn months and included aggregation sizes of up to 1398 individuals, the largest aggregation ever reported for this species. The aggregations were associated with sea surface temperatures of 13-24° C and chlorophyll-a concentrations of 0·4-2·6 mg m-3 and during one aggregation, a high abundance of zooplankton prey was present. Photogrammetric tools allowed for the estimation of total body lengths ranging between 4 and 8 m. Characterization of these events provides new insight into the potential biological function of large aggregations in this species.


Subject(s)
Animal Distribution , Sharks , Animals , Atlantic Ocean , Copepoda , Ecosystem , Photogrammetry , Remote Sensing Technology , Seasons , Temperature , Zooplankton
5.
Obes Rev ; 18(3): 293-308, 2017 03.
Article in English | MEDLINE | ID: mdl-28085991

ABSTRACT

Post-term birth is a preventable cause of perinatal mortality and severe morbidity. This review examined the association between maternal body mass index (BMI) and post-term birth at ≥42 and ≥41 weeks' gestation. Five databases, reference lists and citations were searched from May to November 2015. Observational studies published in English since 1990 were included. Linear and nonlinear dose-response meta-analyses were conducted by using random effects models. Sensitivity analyses assessed robustness of the results. Meta-regression and sub-group meta-analyses explored heterogeneity. Obesity classes were defined as I (30.0-34.9 kg m-2 ), II (35.0-39.9 kg m-2 ) and III (≥40 kg m-2 ; IIIa 40.0-44.9 kg m-2 , IIIb ≥ 45.0 kg m-2 ). Searches identified 16,375 results, and 39 studies met the inclusion criteria (n = 4,143,700 births). A nonlinear association between maternal BMI and births ≥42 weeks was identified; odds ratios and 95% confidence intervals for obesity classes I-IIIb were 1.42 (1.27-1.58), 1.55 (1.37-1.75), 1.65 (1.44-1.87) and 1.75 (1.50-2.04) respectively. BMI was linearly associated with births ≥41 weeks: odds ratio is 1.13 (95% confidence interval 1.05-1.21) for each 5-unit increase in BMI. The strength of the association between BMI and post-term birth increases with increasing BMI. Odds are greatest for births ≥42 weeks among class III obesity. Targeted interventions to prevent the adverse outcomes associated with post-term birth should consider the difference in risk between obesity classes.


Subject(s)
Body Mass Index , Infant, Postmature , Mothers , Obesity/epidemiology , Body Weight , Databases, Factual , Female , Gestational Age , Humans , Infant, Newborn , Non-Randomized Controlled Trials as Topic , Observational Studies as Topic , Pregnancy , Pregnancy Complications , Socioeconomic Factors
6.
Sci Rep ; 6: 30088, 2016 07 21.
Article in English | MEDLINE | ID: mdl-27439482

ABSTRACT

A need exists to noninvasively assess renal interstitial fibrosis, a common process to all kidney diseases and predictive of renal prognosis. In this translational study, Magnetic Resonance Imaging (MRI) T1 mapping and a new segmented Diffusion-Weighted Imaging (DWI) technique, for Apparent Diffusion Coefficient (ADC), were first compared to renal fibrosis in two well-controlled animal models to assess detection limits. Validation against biopsy was then performed in 33 kidney allograft recipients (KARs). Predictive MRI indices, ΔT1 and ΔADC (defined as the cortico-medullary differences), were compared to histology. In rats, both T1 and ADC correlated well with fibrosis and inflammation showing a difference between normal and diseased kidneys. In KARs, MRI indices were not sensitive to interstitial inflammation. By contrast, ΔADC outperformed ΔT1 with a stronger negative correlation to fibrosis (R(2) = 0.64 against R(2) = 0.29 p < 0.001). ΔADC tends to negative values in KARs harboring cortical fibrosis of more than 40%. Using a discriminant analysis method, the ΔADC, as a marker to detect such level of fibrosis or higher, led to a specificity and sensitivity of 100% and 71%, respectively. This new index has potential for noninvasive assessment of fibrosis in the clinical setting.


Subject(s)
Fibrosis/diagnosis , Fibrosis/pathology , Image Processing, Computer-Assisted/methods , Kidney Diseases/diagnosis , Kidney Diseases/pathology , Magnetic Resonance Imaging/methods , Adult , Aged , Animals , Female , Histocytochemistry , Humans , Male , Middle Aged , Rats , Sensitivity and Specificity
7.
Br J Surg ; 103(4): 417-26, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26891212

ABSTRACT

BACKGROUND: Livers with parenchymal abnormalities tolerate ischaemia-reperfusion (IR) injury poorly. IR injury is a risk factor for hepatocellular carcinoma (HCC) recurrence. This study assessed the link between liver parenchymal abnormalities and HCC recurrence, and evaluated the protective effect of ischaemic preconditioning. METHODS: C57BL/6 mice were fed a choline-deficient diet for 6 and 12 weeks, or standard chow. Hepatic IR and ischaemic preconditioning were achieved by clamping liver blood inflow. Hepa 1-6 HCC cells were inoculated through the spleen. Thereafter, tumour burden, serum α-fetoprotein and cancer cell aggressiveness were compared among groups. RESULTS: Hepatocellular damage and expression of inflammatory genes (encoding interleukin 6, tumour necrosis factor α, hypoxia inducible factor 1α and E-selectin) were exacerbated after IR injury in mice with severe steatosis. Compared with control livers or those with minimal steatosis, livers exposed to a prolonged choline-deficient diet developed larger tumour nodules and had higher serum α-fetoprotein levels. Non-ischaemic liver lobes from mice with steatosis were not protected from accelerated tumour growth mediated by IR injury. This remote effect was linked to promotion of the aggressiveness of HCC cells. Ischaemic preconditioning before IR injury reduced the tumour burden to the level of that in non-ischaemic steatotic controls. This protective effect was associated with decreased cancer cell motility. CONCLUSION: Livers with steatosis tolerated IR poorly, contributing to more severe HCC recurrence patterns in mice with increasingly severe steatosis. IR injury also had a remote effect on cancer cell aggressiveness. Ischaemic preconditioning before IR injury reduced tumour load and serum α-fetoprotein levels. SURGICAL RELEVANCE: Liver ischaemia-reperfusion (IR) injury is associated with organ dysfunction and surgical morbidity. Livers with steatosis tolerate IR injury poorly in the setting of both liver resection and liver transplantation. Ischaemic preconditioning is a simple method to mitigate IR injury. This study shows that ischaemic preconditioning of mouse livers with steatosis reduces ischaemia-mediated tumour growth acceleration. Liver parenchymal abnormalities such as warm IR injury and liver steatosis should be taken into account to predict accurately the risk of liver cancer recurrence after surgical management. Ischaemic preconditioning strategies may hold therapeutic potential not only to mitigate surgical morbidity but also to reduce postoperative recurrence of liver cancer.


Subject(s)
Carcinoma, Hepatocellular/therapy , Fatty Liver/etiology , Ischemic Preconditioning/methods , Liver Neoplasms/therapy , Neoplasms, Experimental , Animals , Biomarkers, Tumor/biosynthesis , Biomarkers, Tumor/genetics , Blotting, Western , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/pathology , Cell Line, Tumor , Cell Movement , Cell Proliferation , DNA, Neoplasm/genetics , Fatty Liver/genetics , Fatty Liver/therapy , Gene Expression Regulation , Immunohistochemistry , Liver Neoplasms/genetics , Liver Neoplasms/pathology , Male , Mice , Mice, Inbred C57BL , Real-Time Polymerase Chain Reaction
8.
J Hosp Infect ; 82(3): 194-202, 2012 Nov.
Article in English | MEDLINE | ID: mdl-23017384

ABSTRACT

BACKGROUND: Influenza immunization for healthcare personnel reduces frequency and severity of nosocomial influenza outbreaks and influenza-associated morbidity and mortality among patients. The Ottawa Influenza Decision Aid (OIDA) was developed to assist undecided healthcare workers in deciding whether or not to be immunized. AIM: To assess the impact of the OIDA, and to ascertain whether its use would increase the level of confidence in healthcare workers' influenza immunization decision and positively affect their intent to be immunized. METHODS: Single-centre, single-blind, parallel-group, randomized controlled trial. FINDINGS: Eight per cent (151 of 1886) of the unimmunized healthcare personnel were randomized. Of 107 eligible respondents, 48 were in the Ottawa Influenza Decision Aid (OIDA) group and 59 in the control group. A statistically significant (P = 0.020) greater improvement in confidence in immunization decision was observed in the OIDA group compared with the control group. Whereas the odds of changing intent to be immunized from 'no/unsure' to 'yes' was 2.4 times greater in the OIDA group, this result did not reach statistical significance after adjusting for intent to be immunized at baseline. The post-OIDA intent to be immunized in the OIDA and control groups compared to the pre-OIDA intent to be immunized showed that the OIDA had a significant effect on reducing uncertainty (P = 0.035). CONCLUSIONS: Using an accessible, balanced, understandable format for all healthcare personnel about their influenza immunization decision appears to have an impact on both healthcare personnel's confidence in their immunization decision and in their intent to be immunized.


Subject(s)
Attitude of Health Personnel , Decision Support Techniques , Health Personnel , Immunization/statistics & numerical data , Influenza, Human/prevention & control , Patient Acceptance of Health Care/statistics & numerical data , Adolescent , Adult , Aged , Female , Humans , Male , Middle Aged , Ontario , Single-Blind Method , Young Adult
9.
Magn Reson Med ; 68(5): 1544-52, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22294467

ABSTRACT

The emerging importance of nanoparticle technology, including iron oxide nanoparticles for monitoring development, progression, and treatment of inflammatory diseases such as arthritis, drives development of imaging techniques. Studies require an imaging protocol that is sensitive and quantifiable for the detection of iron oxide over a wide range of concentrations. Conventional signal loss measurements of iron oxide nanoparticle containing tissues saturate at medium concentrations and show a nonlinear/nonproportional intensity to concentration profile due to the competing effects of T1 and T2 relaxation. A concentration calibration phantom and an in vivo study of intra-articular injection in a rat knee of known concentrations of iron oxide were assessed using the difference-ultrashort echo time sequence giving a positive, quantifiable, unambiguous iron signal and monotonic, increasing concentration response over a wide concentration range in the phantom with limited susceptibility artifacts and high contrast in vivo to all other tissues. This improved dynamic response to concentration opens possibilities for quantification due to its linear nature at physiologically relevant concentrations.


Subject(s)
Algorithms , Dextrans/administration & dosage , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Joints/anatomy & histology , Magnetic Resonance Imaging/methods , Magnetite Nanoparticles/administration & dosage , Animals , Contrast Media/administration & dosage , Female , Injections, Intra-Arterial , Rats , Rats, Inbred Lew , Reproducibility of Results , Sensitivity and Specificity
10.
Eur J Appl Physiol ; 112(7): 2421-32, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22045413

ABSTRACT

This study investigated the acute effects of NMES on blood lactate (BLa) and performance parameters in trained male triathletes. On three separate days, 13 trained male triathletes performed six 30 s Wingate tests (30 WanT) on a cycle ergometer. Each session consisted of performing 3 × 30 WanT (bouts 1-3) followed by a randomly assigned 30 min recovery intervention of either: (i) passive (seated), (ii) active (cycling at 30% VO(2 max)) or (iii) NMES (1 Hz/500 µs-ON:OFF 2:6 s). The 3 × 30 WanT bouts were then repeated (bouts 4-6) and compared to bouts 1-3 for peak power (PP), mean power (MP) and fatigue index (FI). BLa and heart rate (HR) were recorded at designated time points throughout. Data were analyzed using repeated measures ANOVA with Tukey's honestly significant difference post hoc test. BLa decreased significantly faster during the active recovery intervention (P < 0.001), however, there were no significant differences between interventions for PP (P = 0.217), MP (P = 0.477) and FI (P = 0.234) when the post intervention bouts (4-6) where compared to the pre intervention bouts (1-3). NMES during recovery was not more effective than active or passive recovery for improving subsequent performance. Despite BLa clearing at a significantly faster rate for the active recovery intervention, PP, MP or FI did not improve significantly compared to NMES and passive. In conclusion, NMES does not appear to be more effective than traditional methods for enhancing short-term recovery from supra-maximal exercise bouts in trained male triathletes.


Subject(s)
Anaerobic Threshold/physiology , Electric Stimulation Therapy/methods , Muscle Fatigue/physiology , Physical Exertion/physiology , Recovery of Function/physiology , Sports/physiology , Adult , Humans , Male , Treatment Outcome , Young Adult
11.
Am J Transplant ; 11(6): 1158-68, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21564535

ABSTRACT

The Automatic Quantitative Ultrashort Echo Time imaging (AQUTE) protocol for serial MRI allows quantitative in vivo monitoring of iron labeled pancreatic islets of Langerhans transplanted into the liver, quantifying graft implantation and persistence in a rodent model. Rats (n = 14), transplanted with iron oxide loaded cells (0-4000 islet equivalents, IEQ), were imaged using a 3D radial ultrashort echo time difference technique (dUTE) on a Siemens MAGNETOM 3T clinical scanner up to 5 months postsurgery. In vivo 3D dUTE images gave positive contrast from labeled cells, suppressing liver signal and small vessels, allowing automatic quantification. Position of labeled islet clusters was consistent over time and quantification of hyperintense pixels correlated with the number of injected IEQs (R² = 0.898, p < 0.0001), and showed persistence over time (5 months posttransplantation). Automatic quantification was superior to standard imaging and manual counting methods, due to the uniform suppressed background and high contrast, resulting in significant timesavings, reproducibility and ease of quantification. Three-dimensional coverage of the whole liver in the absence of cardiac/respiratory artifact provided further improvement over conventional imaging. This imaging protocol reliably quantifies transplanted islet mass and has high translational potential to clinical studies of transplanted pancreatic islets.


Subject(s)
Contrast Media , Islets of Langerhans Transplantation , Islets of Langerhans/pathology , Magnetic Resonance Imaging/methods , Animals , Rats , Rats, Sprague-Dawley , Reproducibility of Results
12.
Clin Psychol Rev ; 31(5): 767-85, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21513693

ABSTRACT

Advances in neuroscience have added to the understanding of social functioning which has become an increasing area of focus in the psychology and neuropsychology literature. Given importance of appropriate social functioning to everyday interactions, as well as psychological well-being, accurately identifying and documenting such functions constitute a critical undertaking for both researchers and clinicians in psychology and related health professions. This review aimed to identify available social function assessment tools for children and adolescents using a comprehensive search method. Eighty-six measures were identified. Information on the assessment tools including the theoretical model they are based on, age range, sample used in development, and psychometric information are described. Results will aid researchers, psychologists and other health professionals in the selection of an appropriate tool to assess social function.


Subject(s)
Interpersonal Relations , Social Adjustment , Social Behavior , Adolescent , Child , Humans , Psychometrics
13.
Mikrobiologiia ; 78(5): 690-4, 2009.
Article in English | MEDLINE | ID: mdl-19899441

ABSTRACT

We have found that incubation in lactose solutions (0.75 M) of yeast culture Saccharomyces cerevisiae sensitive to dehydration damage increased the stability of the cells during dehydration. Simultaneously with this increase in viability, a decrease in plasma membrane permeability during rehydration was seen. Using Fourier transform infrared spectroscopy to measure lipid phase transitions, we observed that the lactose treatment depressed the membrane phospholipid phase transition temperature in a sensitive culture of dry yeast. As a result, it leads to the decrease in the damages of molecular organization of membranes during rehydration of dry yeast cells, thus reducing leakage from the cells.


Subject(s)
Adaptation, Physiological , Lactose/physiology , Saccharomyces cerevisiae/physiology , Water-Electrolyte Balance/physiology , Cell Membrane/metabolism , Cell Membrane Permeability , Lactose/metabolism , Lactose/pharmacology , Phospholipids/metabolism , Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae/metabolism
14.
Atherosclerosis ; 183(2): 361-6, 2005 Dec.
Article in English | MEDLINE | ID: mdl-16285999

ABSTRACT

PURPOSE: To determine, in asymptomatic subjects, the inter-study reproducibility of a three-dimensional (3D) volume selective fast spin echo (FSE) cardiovascular magnetic resonance sequence for the assessment of carotid artery wall volume as a measure of atheroma burden. METHODS: Inter-study reproducibility was evaluated in 16 asymptomatic volunteers (10 male, 6 female). Both carotid arteries were scanned twice with a median inter-scan time of 5 days. The images were acquired in cross-section, and the total carotid arterial wall volume (TWV) was calculated by subtraction of the total carotid lumen volume from the total outer carotid vessel volume. RESULTS: The mean carotid T1-weighted TWV for the first and second scans was 828 and 821 mm(3), respectively (mean difference 7 mm(3), p=0.45). The standard deviation (S.D.) of the differences between the measurements was 38 mm(3) yielding an inter-study coefficient of variation of 4.6%. The time for each study was approximately 30 min. For the longitudinal evaluation of carotid atheroma burden with pharmacological intervention versus placebo, 32 subjects would enable a difference of 38 mm(3) to be detected with a significance level of 5% with 80% power. CONCLUSION: Volumetric analysis with carotid CMR in asymptomatic subjects using a 3D volume-selective FSE is time-efficient with good inter-study reproducibility, and is well suited for longitudinal studies of carotid atheroma with reasonable sample sizes.


Subject(s)
Carotid Artery, Common/anatomy & histology , Carotid Artery, Internal/anatomy & histology , Magnetic Resonance Imaging/methods , Adult , Aged , Atherosclerosis/diagnosis , Carotid Artery Diseases/diagnosis , Female , Follow-Up Studies , Humans , Male , Middle Aged , Reference Values , Reproducibility of Results , Retrospective Studies , Risk Factors
15.
Conf Proc IEEE Eng Med Biol Soc ; 2004: 1415-8, 2004.
Article in English | MEDLINE | ID: mdl-17271959

ABSTRACT

The link between atherosclerosis and wall shear stress (WSS) has lead to considerable interest in the in vivo estimation of WSS. Both magnetic resonance imaging (MRI) and three-dimensional ultrasound (3DUS) are capable of providing the anatomical and flow data required for subject-specific computational fluid dynamics (CFD) simulations. This study compares, for the first time, predicted 3D flow patterns based on black blood MRI and 3DUS. Velocity fields in the carotid arteries of nine subjects have been reconstructed, and the haemodynamic wall parameters WSS, oscillatory shear index (OSI), WSS gradients (WSSG) and angle gradients (WSSAG) were computed and compared. There was a good qualitative agreement between results derived from MRI and 3DUS, embodied by a strong linear correlation between the patched representations of the haemodynamic wall parameters. The root-mean-square error between haemodynamic wall parameters was comparable to the range of the expected variability of each imaging technique (WSS: 0.411 N/m; OSI: 0.048; temporal WSSG: 2.29 N/(s.m/sup 2/); spatial WSSG: 150 N/m/sup 3/; WSSAG: 87.6 rad/m). In conclusion, MRI and 3DUS are comparable techniques for combining with CFD in the carotid artery. The relatively high cost of MRI favour 3DUS to MRI for future haemodynamic studies of superficial arteries.

16.
Physiol Meas ; 25(6): 1495-509, 2004 Dec.
Article in English | MEDLINE | ID: mdl-15712727

ABSTRACT

Atherosclerosis is a major cause of morbidity and mortality. Its apparent link with wall shear stress (WSS) has led to considerable interest in the in vivo estimation of WSS. Determining WSS by combining medical images with computational fluid dynamics (CFD) simulations can be performed both with magnetic resonance imaging (MRI) and three-dimensional ultrasound (3DUS). This study compares predicted 3D flow patterns based on black blood MRI and 3DUS. Velocity fields in the carotid arteries of nine subjects have been reconstructed, and the haemodynamic wall parameters WSS, oscillatory shear index (OSI), WSS gradients (WSSG) and angle gradients (WSSAG) were compared between the two imaging techniques. There was a good qualitative agreement between results derived from MRI and 3DUS (average correlation strength above 0.60). The root mean square error between haemodynamic wall parameters was comparable to the range of the expected variability of each imaging technique (WSS: 0.411 N m(-2); OSI: 0.048; temporal WSSG: 150 N s(-1) m(-2); spatial WSSG: 2.29 N m(-3); WSSAG: 87.6 rad m(-1)). In conclusion, MRI and 3DUS are capable of providing haemodynamic parameters when combined with CFD, and the predictions are in most cases qualitatively and quantitatively similar. The relatively high cost of MRI and continuing improvement in ultrasound favour US to MRI for future haemodynamic studies of superficial arteries.


Subject(s)
Algorithms , Blood Flow Velocity/physiology , Carotid Arteries/diagnostic imaging , Carotid Arteries/physiology , Image Interpretation, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Models, Cardiovascular , Adult , Carotid Arteries/anatomy & histology , Computer Simulation , Echocardiography, Three-Dimensional/methods , Female , Humans , Information Storage and Retrieval/methods , Male , Middle Aged , Reproducibility of Results , Sensitivity and Specificity
17.
Ann Clin Biochem ; 40(Pt 6): 697-700, 2003 Nov.
Article in English | MEDLINE | ID: mdl-14629812

ABSTRACT

BACKGROUND: The Dade Behring Syva(R) EMIT (enzyme multiplied immunoassay technique) method for the measurement of tacrolimus in whole blood was evaluated against the Abbott IMx(R) microparticle enzyme immunoassay (MEIA) method. EMIT measures tacrolimus colorimetrically, whereas MEIA measures the analyte using fluorimetry. Both methods incorporate a protein precipitation step prior to measurement. METHOD: Whole blood specimens were treated by two types of precipitation technique followed by analysis for tacrolimus by either MEIA or EMIT on the Bayer Advia 1650. Linearity and precision were assessed and correlation analysis performed to evaluate the EMIT assay on the Bayer Advia 1650. RESULTS: The EMIT tacrolimus assay was linear over the concentration range 0.0-22.0 micro g/L; the limit of detection was 1.2 micro g/L. Correlation between the Syva EMIT and IMx tacrolimus assays was excellent (r = 0.959) and no significant bias existed between the two methods (mean difference, delta = 0.221 micro g/L). Calibration data for the EMIT assay was stable for a period of 24-48 h on the Advia between runs. CONCLUSION: The Syva EMIT assay for the measurement of tacrolimus in whole blood is suited for daily routine use on the Bayer Advia 1650.


Subject(s)
Enzyme Multiplied Immunoassay Technique/instrumentation , Enzyme Multiplied Immunoassay Technique/standards , Tacrolimus/blood , Blood Chemical Analysis , Calibration , Tacrolimus/immunology
18.
J Microbiol Methods ; 55(1): 311-4, 2003 Oct.
Article in English | MEDLINE | ID: mdl-14500023

ABSTRACT

This study describes the application of filtration, infrared spectroscopy, and multivariate analysis to the identification of 10 foodborne bacterial species. The bacteria were applied by filtration to a disposable optical membrane that is transparent to infrared radiation. The filtration step was rapid (2 min). Observed cellular infrared spectra were unique and were used to discriminate among the different species. A dataset for the 10 bacterial species investigated was successfully used to correctly identify unknowns included in the dataset.


Subject(s)
Bacteria/isolation & purification , Bacteria/classification , Filtration , Membranes , Multivariate Analysis , Spectrophotometry, Infrared
20.
Med Phys ; 30(12): 3251-61, 2003 Dec.
Article in English | MEDLINE | ID: mdl-14713092

ABSTRACT

Image-based Computational Fluid Dynamics (CFD) has become a popular tool for the prediction of in vivo flow profiles and hemodynamic wall parameters. Currently, Magnetic Resonance Imaging (MRI) is most widely used for in vivo geometry acquisition. For superficial arteries such as the carotids and the femoral artery, three-dimensional (3-D) extravascular ultrasound (3-DUS) could be a cost-effective alternative to MRI. In this study, nine healthy subjects were scanned both with MRI and 3-DUS. The reconstructed carotid artery geometries for each subject were compared by evaluating cross-sectional areas, centerlines, and carotid nonplanarity. Lumen areas agreed very well between the two different acquisition techniques, whereas centerlines and nonplanarity parameters showed measurable disagreement, possibly due to the different neck and head positions adopted for 3-DUS versus MRI. With the current level of agreement achieved, 3-DUS has the potential to become an inexpensive and fast alternative to MRI for image-based CFD modeling of superficial arteries.


Subject(s)
Anatomy, Cross-Sectional/methods , Carotid Arteries/anatomy & histology , Carotid Arteries/diagnostic imaging , Echocardiography, Three-Dimensional/methods , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Adult , Female , Humans , Male , Middle Aged , Reproducibility of Results , Sensitivity and Specificity , Subtraction Technique
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