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Biomedical subjects

Andrew J Taylor

Publications and source records attributed to Andrew J Taylor.

At least 37 records · Page 2Linked to original sources
PubMed2005

Smuggled tobacco, deprivation and addiction.

OBJECTIVE: To identify the links between smuggled tobacco, deprivation and addiction across one Health Authority in the North East of England and identify the impact on people living in disadvantaged areas. DESIGN: Anonymous postal survey. Sample size 11 443. Multivariate analysis including an 'Ideal Types analysis' examined the probabilities of purchase of smuggled tobacco and associations with population characteristics. SETTING: Sample taken from across the Hull & East Riding Health Authority area in the UK. PARTICIPANTS: Randomly selected from those aged 16 and over, who were registered with a GP in the Health Authority area on the 1 September 2000. RESULTS: The predicted probability of having ever bought smuggled tobacco for a male, employed, heavy smoker living in a deprived area was 0.67. A female with the same characteristics had a probability of 0.49. For the unemployed the probabilities are 0.55 and 0.37 respectively. For respondents living in non-deprived areas the probability of having ever bought smuggled tobacco was much lower. This probability was further reduced for respondents who were unemployed. Respondents living in deprived areas had a 134% higher probability of being heavily addicted to tobacco. Links between addiction and deprivation are confirmed. CONCLUSIONS: This study confirms and extends the findings of previous qualitative studies. The results of this analysis demonstrate that people who have bought smuggled tobacco are heavy smokers with high levels of addiction, living in socially deprived areas, but are more likely to be in employment. They are likely to use smuggled tobacco to save money and sustain their smoking habit.

Adolescent↗
PubMed2005

Model studies on retention of added volatiles during breadcrumb production.

Breadcrumb samples were prepared with a range of volatile compounds at known concentrations. The retention of these volatiles was assessed via solvent extraction and quantification by gas chromatography-mass spectrometry. Volatile loss during processing was shown to be substantial and dependent upon the compound's vapor pressure. The influence of initial concentration levels on the retention of volatiles was linear within the bounds of the experimental concentrations (0-300 mg/kg). Comparison of volatile concentration at various stages throughout the production process (by headspace analysis) showed that the greatest losses occurred during the processing stages that involved heat, namely, microwave heating and drying. The production of samples by freeze drying showed an increased average retention of 17% as compared to fluidized bed drying and flat bed drying, which showed the highest volatile losses.

Bread↗
PubMed2005

Microcomputed tomography colonography for polyp detection in an in vivo mouse tumor model.

This study was initiated to evaluate the efficacy of negative contrast-enhanced microcomputed tomography (microCT) colonography for the noninvasive detection of colonic tumors in living mice. After colonic preparation, 20 anesthetized congenic mice were scanned with high-resolution microCT. Images were displayed by using commercial visualization software and interpreted by two gastrointestinal radiologists, who were unaware of tumor prevalence and findings at gross pathology. Two-dimensional multiplanar images were assessed by using a five-point scale to distinguish colonic tumors (polyps) from fecal pellets (5 = definitely a tumor, 4 = probably a tumor, 3 = indeterminate, 2 = probably not a tumor, 1 = definitely not a tumor). Gross pathologic evaluation of excised mouse colons served as the reference standard. Data analysis included dichotomizing results, with 1-2 indicating no tumor and 3-5 indicating tumor and also receiver operator characteristic curve analysis with area under the curve for threshold-independent assessment. A total of 41 colonic polyps in 18 of the 20 mice were identified at gross examination on necropsy, of which 30 measured 2-5 mm and 11 measured <2 mm in size. The pooled per-polyp sensitivity for lesions >2 mm was 93.3% (56/60). The pooled per-mouse sensitivity for polyps >2 mm was 97.1% (33/34). Pooled specificity for distinguishing fecal pellets from tumor was 98.5% (65/66). The combined area under the curve from receiver operator characteristic curve analysis was 0.810 +/- 0.038 (95% confidence interval, 0.730-0.890). These findings indicate that accurate noninvasive longitudinal monitoring of colon tumor progression or response to various therapies is now technically feasible in live mice by using this microCT colonography method.

Animals↗
PubMed2005

On line monitoring of acrylamide formation.

A system to monitor the formation of acrylamide in model systems and from real food products under controlled conditions of temperature, time and moisture content has been developed. By humidifying the gas that flows through the sample, some control over moisture content can be affected. Results are presented to show the validity and reproducibility of the technique and its ability to deliver quantitative data. The effects of different processing conditions on acrylamide formation and on the development of color, due to the Maillard reaction, are evaluated.

Acrylamide↗
PubMed2005

Metabolite fingerprinting in transgenic lettuce.

Metabolite fingerprinting has been achieved using direct atmospheric pressure chemical ionization-mass spectrometry (APCI-MS) and linked gas chromatography (GC-APCI/EI-MS) for transgenic lettuce (Lactuca sativa L. cv. Evola) plants expressing an IPT gene under the control of the senescence-specific SAG12 promoter from Arabidopsis thaliana (P(SAG12)-IPT). Mature heads of transgenic lettuce and their azygous controls were maintained under defined conditions to assess their shelf life. Transgenic lettuce plants exhibited delayed senescence and significant increases (up to a maximum of threefold) in the concentrations of three volatile organic compounds (VOCs), corresponding to molecular masses of 45, 47 and 63, when compared with heads from azygous plants. These VOCs were identified as acetaldehyde (45), ethanol (47) and dimethyl sulphide (63). The increase in dimethyl sulphide was paralleled by an accumulation of reactive oxygen species (ROS) in the heads of transgenic plants. These results demonstrate the applicability of metabolic fingerprinting techniques to elucidate the underlying pleiotropic responses of plants to transgene expression.

Journal Article↗
PubMed2005

Linear polyp measurement at CT colonography: in vitro and in vivo comparison of two-dimensional and three-dimensional displays.

PURPOSE: To compare the accuracy of polyp measurement at computed tomographic (CT) colonography by using two-dimensional (2D) multiplanar reformation (MPR) and three-dimensional (3D) endoluminal displays obtained both in a colon phantom and at clinical examinations. MATERIALS AND METHODS: This HIPAA-compliant study had institutional review board approval, and all patients provided signed informed consent, both of which allowed for additional retrospective evaluation. Two-dimensional and 3D CT colonography displays were generated from data obtained in an in vitro colon phantom that contained 10 6-13-mm synthetic polyps and from data obtained at in vivo clinical CT colonography examinations performed in 10 patients (five men, five women; mean age, 56.3 years) with proved polyps (size range, 7-25 mm). The reference standard for in vivo polyp size was optical colonoscopic measurement with a calibrated linear probe. Polyps were measured at CT colonography with 2D MPR and 3D endoluminal displays and electronic calipers by four radiologists who were unaware of the reference size measurements. The largest of the three 2D MPR measurements was considered the "optimized" 2D projection. Statistical analysis was performed with Wilcoxon signed rank, repeated-measures analysis of variance, and paired t testing. RESULTS: For the phantom, the mean errors (differences between actual polyp size and that measured at CT colonography) for 2D transverse, 2D coronal, and 3D endoluminal displays were 1.6 mm +/- 0.8 (standard deviation), 1.4 mm +/- 0.7, and 0.8 mm +/- 0.5, respectively. For in vivo polyp measurements, the mean errors for 2D transverse, 2D coronal, 2D sagittal, and 3D displays were 4.4 mm +/- 3.5, 3.8 mm +/- 3.3, 4.6 mm +/- 3.0, and 1.9 mm +/- 1.6, respectively. The 2D measurements underestimated actual polyp sizes in all cases. The differences in mean errors between 2D MPR and 3D endoluminal measurements were significant (P < .05). When the optimized 2D view was considered for in vivo measurement, the mean error decreased to 3.0 mm +/- 2.6 (P = .2). CONCLUSION: Linear polyp measurement on 3D endoluminal views was significantly more accurate than measurement on 2D transverse, coronal, or sagittal views, both in vitro and in vivo, for the CT colonography system evaluated. Use of the optimized 2D view substantially reduced 2D measurement error and may be valuable when used in conjunction with 3D measurement.

Analysis of Variance↗
PubMed2005

Cardiac troponin I concentrations, but not electrocardiographic results, predict an extended hospital stay after coronary artery bypass graft surgery.

BACKGROUND: Cardiac damage in coronary artery graft (CABG) surgery is an important contributor to postoperative cardiac dysfunction and delayed hospital discharge. Currently, no simple method exists for its quantification. METHODS: In a prospective study of 300 patients having routine CABG surgery, we compared cardiac troponin I (cTnI) concentrations at 6 and 24 h after surgery with electrocardiographic (ECG) results as predictors of an extended postoperative stay in the intensive care unit (ICU) and in the hospital. We stratified outcome variables by tertiles of cTnI concentration and studied the significance of differences between outcome variables across tertiles. RESULTS: Multivariate analysis showed that 24-h cTnI is a significant predictor of increased postoperative ICU stay (P = 0.012) and postoperative hospital stay (P = 0.024). For 6-h cTnI, corresponding significance values were P = 0.29 and 0.9. ECG was of no value (P = 0.39 and 0.47). Differences in 24-h cTnI were highly significant, particularly for lowest vs highest tertiles, and allowed stratification of risk into "low" (<10 microg/L), "equivocal" (10-20 microg/L), and "high" (>20 microg/L). CONCLUSIONS: Use of a single 24-h cTnI value to quantify perioperative myocardial damage identifies patients who are at greater risk of extended ICU and hospital stays. This strategy could assist in allocation of patients to different management streams after CABG surgery.

Analysis of Variance↗
PubMed2004

Direct coupling of supercritical fluid extraction to a gas phase atmospheric pressure chemical ionisation source ion trap mass spectrometer for fast extraction and analysis of food components.

Supercritical fluid extraction (SFE) was coupled to a custom-built atmospheric pressure chemical ionization (APCI) source of an ion trap mass spectrometer (ITMS). This method was developed for the monitoring of static or dynamic carbon dioxide extraction of volatile aroma compounds in real time. The gas phase APCI source resulted in simple spectra where the extraction of individual compounds could be monitored. A classical mint extraction was used to demonstrate the possibilities of the method. Influence of cell loading and standard injection possibilities are described. Limit of detection of the system was 0.5 nl or lower for a series of test compounds. Prospect for a fast method for extraction and quantification was raised and discussed.

Atmospheric Pressure↗
PubMed2004

Delayed enhancement and T2-weighted cardiovascular magnetic resonance imaging differentiate acute from chronic myocardial infarction.

BACKGROUND: Delayed enhancement (DE) cardiovascular magnetic resonance (CMR) detects acute and chronic myocardial infarction (MI) by visualizing contrast media accumulation in infarcted segments. T2-weighted CMR depicts infarct-related myocardial edema as a marker of acute but not chronic myocardial injury. We investigated the clinical utility of an approach combining both techniques to differentiate acute from chronic MI. METHODS AND RESULTS: Seventy-three MI patients were studied in 2 groups. Group A consisted of 15 acute MI patients who were studied twice, on day 1 and 3 months after MI. In group B, 58 patients with acute or chronic MI underwent 1 CMR scan. T2-weighted and DE images of matched slices were acquired on a 1.5-T system. In group A, quantitative segmental and region of interest-based analyses were performed to observe signal changes between the acute and chronic phases. In group B, T2-weighted and DE images were examined visually by 2 blinded observers for the presence or absence of hyperintense areas in corresponding segments. For infarct localization, coronary angiography and/or ECG changes served as the reference standard. In group A, the contrast-to-noise ratio on T2-weighted images dropped in the infarcted segments from 2.7+/-1.1 on day 1 to 0.1+/-1.2 after 3 months (P<0.0001). There was no significant change in contrast-to-noise ratio in DE images (1.9+/-1.5 versus 1.3+/-1.0; P=NS). The qualitative assessment of T2-weighted and DE images in group B yielded a specificity of 96% to differentiate acute from chronic lesions. CONCLUSIONS: An imaging approach combining DE and T2-weighted CMR accurately differentiates acute from chronic MI.

Acute Disease↗
PubMed2004

Detection of acutely impaired microvascular reperfusion after infarct angioplasty with magnetic resonance imaging.

BACKGROUND: Despite the reopening of the infarct-related artery (IRA) with infarct angioplasty, complete microvascular reperfusion does not always ensue. METHODS AND RESULTS: We performed cardiovascular MRI (CMR) in 20 acute myocardial infarction (AMI) patients within 24 hours of successful infarct angioplasty and 10 control patients without obstructive coronary artery disease on a clinical 1.5-T CMR scanner. Three-month follow-up CMR in AMI patients evaluated the impact of abnormal reperfusion on recovery of function. Infarction was localized by delayed contrast hyperenhancement and impaired systolic thickening. Microvascular perfusion was assessed at rest by first-pass perfusion CMR after a bolus of gadolinium-DTPA by use of the time to 50% maximum myocardial enhancement. Whereas contrast wash-in was homogeneous in control patients, AMI patients exhibited delays in the hypokinetic region subtended by the IRA compared with remote segments in 19 of 20 patients, with a mean contrast delay of 0.9+/-0.1 seconds (95% CI, 0.6 to 1.2 seconds). At follow-up, the mean recovery of systolic thickening was lower in segments with a contrast delay of 2 seconds or more (10+/-7% versus 39+/-4%, P<0.001). A contrast delay > or =2 seconds and infarction >75% transmurally were independent predictors of impaired left ventricular systolic thickening at 3 months (P=0.002 for severe contrast delay, P=0.048 for >75% for transmural infarction). CONCLUSIONS: CMR detects impaired microvascular reperfusion in AMI patients despite successful infarct angioplasty, which when severe is associated with a lack of recovery of wall motion.

Abciximab↗
PubMed2004

Effect of beta-cyclodextrin on aroma release and flavor perception.

Binding and release of volatile compounds to and from beta-cyclodextrin were measured in model aqueous systems using static equilibrium headspace and dynamic headspace dilution. Beta-cyclodextrin decreased the static equilibrium headspace for some volatiles (e.g., ethyl octanoate and decanone) due to binding, but dilution studies demonstrated that binding was readily reversible. Dynamic release of hydrophobic volatile compounds was similar to that observed from emulsions. When beta-cyclodextrin was added to fat free yogurt, the release of a commercial lemon flavoring was modified and was similar to release from a regular fat yogurt. Sensory difference testing confirmed the release results. The data demonstrate that beta-cyclodextrin can be used to modify flavor delivery in both model and real systems; the effects in the latter are sensorially significant.

Cyclodextrins↗
PubMed2004

Serotonin blockade protects against early microvascular constriction following atherosclerotic plaque rupture.

Early microvascular constriction following atherosclerotic plaque rupture may be mediated via serotonin and/or endothelin-1. Atherosclerotic lesions in the rabbit hindlimb underwent plaque rupture, resulting in a rapid reduction of distal flow (7.1+/-0.7 ml/min pre-rupture versus 3.6+/-0.6 ml/min post-rupture, P<0.001) and a rise in distal microvascular resistance (10.5+/-0.9 mm Hg min/ml pre-rupture versus 23.5+/-3.5 mm Hg min/ml post-rupture, P=0.01). Distal microvascular resistance remained elevated following endothelin-1 receptor antagonism and control vehicle, but normalised after serotonin receptor antagonism with ritanserin (10.5+/-0.9 mm Hg min/ml pre-rupture versus 22.2+/-6.0 mm Hg min/ml post-endothelin-1 receptor antagonism [P<0.05] versus 21.6+/-6.2 mm Hg min/ml post-control vehicle [P<0.05] versus 11.6+/-2.0 mm Hg min/ml post-ritanserin [P=NS]). Early antagonism of serotonin receptors protects against distal microvascular constriction following atherosclerotic plaque rupture.

Animals↗
PubMed2004

2. In vivo nonvolatile release during eating of a model cheese: relationships with oral parameters.

This study deals with the release kinetics of nonvolatile compounds (NVC) (leucine, phenylalanine, glutamic acid, citric acid, lactic acid, propanoic acid, sodium, potassium, calcium, magnesium, chloride, and phosphates) during the eating of a model cheese and the relationships to some oral (salivary and masticatory) parameters. The aroma release has previously been characterized in similar conditions [Pionnier, E.; Chabanet, C.; Mioche, L.; Le Quéré, J.-L.; Salles, C. J. Agric. Food Chem. 2004, 52, xxx-xxx (1)]. Saliva samples were collected from the tongues of eight assessors at different times during and after the chewing sequence. Atmospheric pressure ionization-mass spectrometry and/or high-performance liquid chromatography analyses have been performed on these samples in order to quantify the 12 NVC released in saliva. The maximum concentration (C(max)) in saliva varied significantly according to the compound. However, there was no significant effect of the compound on the time to reach maximum concentration (T(max)). Interindividual differences were observed for most of the parameters and for all of the NVC studied. The parameters extracted from the release profiles of the NVC were closely correlated. High T(max) and AUC (area under the curve) values could be related to high chewing time and low saliva flow rates, low chewing rates, low masticatory performances, and low swallowing rates.

Amino Acids↗
PubMed2004

Myocardial endothelin-1 release and indices of inflammation during angioplasty for acute myocardial infarction and stable coronary artery disease.

BACKGROUND: Elevations in endothelin-1 (ET-1) and inflammatory cytokines may impair myocardial reperfusion through the induction of microvascular constriction or obstruction; however, the generation of these factors close to the site of lesion rupture is unknown. METHODS AND RESULTS: Coronary sinus (CS) and aortic blood was sampled during angioplasty for acute myocardial infarction (AMI) or stable angina to assess the local release of ET-1, interleukin-1beta, interleukin-6, tumor necrosis factor-alpha and C-reactive protein following atherosclerotic plaque rupture. Transthoracic echocardiography documented left ventricular function in AMI. ET-1 levels were higher in CS than in aortic blood in AMI (3.0 +/- 0.3 pmol/L vs 2.6 +/- 0.3 pmol/L, P =.04), but not in stable angina (1.7 +/- 0.2 pmol/L vs 1.5 +/- 0.3 pmol/L, P = NS). CS ET-1 levels were also higher in AMI than in stable angina (3.0 +/- 0.3 pmol/L vs 1.7 +/- 0.2 pmol/L, P =.002), and correlated with left ventricular dysfunction (R(2) = 0.51, P =.02). In contrast, C-reactive protein levels were higher in CS than in aortic blood only in stable angina (2.3 +/- 0.4 mg/L vs 1.8 +/- 0.3 mg/L, P =.01). Similarly, CS tumor necrosis factor-alpha was higher in stable angina than in AMI (6.0 +/- 1.4 pg/mL vs 2.5 +/- 0.9 pg/mL, P =.02). CONCLUSIONS: Local myocardial release of ET-1 is highest in AMI, where it relates to the extent of myocardial dysfunction. Although local inflammation is a component of stable coronary artery disease, it does not appear acutely enhanced in AMI.

Angina Pectoris↗
PubMed2004

Cost-effectiveness of reduction mammaplasty.

OBJECTIVES: The purpose of this study is to provide a comparison of the benefits of reduction mammaplasty (RM) for women with heavy breasts often termed macromastia or breast hypertrophy (BH) surgery. The rationale is to provide information to allow decision-makers to make judgments about the cost-effectiveness of this intervention and make comparisons with other interventions which are commonly undertaken within publicly financed health-care systems. METHODS: Data from a previous outcomes study in Sweden is re-analyzed to derive quality of life measures, from which a mean level of benefit outcome is derived and a cost per quality-adjusted life year is calculated (cost per QALY). RESULTS: The low Cost per QALY suggests that reduction mammaplasty is cost-effective when compared with other treatments which are commonly undertaken. CONCLUSIONS: The authors suggest that the evidence in favor of funding reduction mammaplasty is strong and that decision-makers review their policy in light of this new evidence.

Adult↗
PubMed2004

Volatile release from liquids: a comparison of in vivo APCI-MS, in-mouth headspace trapping and in vitro mouth model data.

In-mouth volatile release from flavoured water was followed using atmospheric pressure chemical ionization-mass spectrometry (APCI-MS) or using a hand-held, computer-controlled device based on sequential trapping of flavours on Tenax traps. The present results verify recent in vitro data obtained with a sophisticated, fully computerized mouth model apparatus and confirm its validity for the simulation of in-mouth dynamic volatile release. In-nose APCI-MS measurements showed considerable person-to-person variability in non-trained individuals during drinking due to subconscious control of muscles during swallowing and subsequent breathing. Data showed a 'swallow breath' volume reaching the nasal cavity from the throat, not from the mouth cavity. Flavour enriched air from the mouth was shown to be transported to the nose (via exhalation) immediately after the swallowing event, but the dynamic process of volatile equilibration between residuals of the swallowed liquid and the exhaled air predominantly determined volatile in-nose concentration. Owing to its dynamic character, the process of volatile equilibration and release in the throat upon exhalation should be similar to the in-mouth process studied in the present work. A full mechanical simulation of retronasal volatile transport, however, will remain difficult.

Beverages↗