Cardiac autonomic function and oesophageal acid sensitivity in patients with non-cardiac chest pain.
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BACKGROUND: Acid reflux can elicit non-cardiac chest pain (NCCP), possibly through altered visceral sensory or autonomic function. The interactions between symptoms, autonomic function, and acid exposure are poorly understood. AIM: To examine autonomic function in NCCP patients during exposure to oesophageal acid infusion. SUBJECTS AND METHODS: Autonomic activity was assessed using power spectral analysis of heart rate variability (PSHRV), before and during oesophageal acidification (0.1 N HCl), in 28 NCCP patients (40.5 (10) years; 13 females) and in 10 matched healthy controls. Measured PSHRV indices included high frequency (HF) (0.15-0.5 Hz) and low frequency (LF) (0.06-0.15 Hz) power to assess vagal and sympathetic activity, respectively. RESULTS: A total of 19/28 patients had angina-like symptoms elicited by acid. There were no significant manometric changes observed in either acid sensitive or insensitive patients. Acid sensitive patients had a higher baseline heart rate (82.9 (3.1) v 66.7 (3.5) beats/min; p<0.005) and lower baseline vagal activity (HF normalised area: 31.1 (1.9)% v 38.9 (2.3)%; p< 0.03) than acid insensitive patients. During acid infusion, vagal cardiac outflow increased (p<0.03) in acid sensitive but not in acid insensitive patients. CONCLUSIONS: Patients with angina-like pain during acid infusion have decreased resting vagal activity. The symptoms elicited by perception of acid are further associated with a simultaneous increase in vagal activity in keeping with a vagally mediated pseudoaffective response. (+info)
Predicting class II MHC/peptide multi-level binding with an iterative stepwise discriminant analysis meta-algorithm.
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MOTIVATION: Predicting peptides that bind to both Major Histocompatibility Complex (MHC) molecules and T cell receptors provides crucial information for vaccine development. An agretope is that portion of a peptide that interacts with an MHC molecule. The identification and prediction of agretopes is the first step towards vaccine design. RESULTS: An iterative stepwise discriminant analysis meta-algorithm is utilized to derive a quantitative motif for classifying potential agretopes as high-, moderate- or non-binders for HLA-DR1, a class II MHC molecule. A large molecular online database provides the input for this data-driven algorithm. The model correctly classifies over 85% of the peptides in the database. AVAILABILITY: Stepwise discriminant analysis software is available commercially in SPSS and BMDP statistical software packages. Peptides known to bind MHC molecules can be downloaded from http://wehih.wehi.edu.au/mhcpep/. Peptides known not to bind HLA-DR1 are available from the author upon request. CONTACT: [email protected]. (+info)
Prediction of acute left main coronary artery obstruction by 12-lead electrocardiography. ST segment elevation in lead aVR with less ST segment elevation in lead V(1).
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OBJECTIVES: We sought to determine the electrocardiographic (ECG) features associated with acute left main coronary artery (LMCA) obstruction. BACKGROUND: Prediction of LMCA obstruction is important with regard to selecting the appropriate treatment strategy, because acute LMCA obstruction usually causes severe hemodynamic deterioration, resulting in a less favorable prognosis. METHODS: We studied the admission 12-lead ECGs in 16 consecutive patients with acute LMCA obstruction (LMCA group), 46 patients with acute left anterior descending coronary artery (LAD) obstruction (LAD group) and 24 patients with acute right coronary artery (RCA) obstruction (RCA group). RESULTS: Lead aVR ST segment elevation (>0.05 mV) occurred with a significantly higher incidence in the LMCA group (88% [14/16]) than in the LAD (43% [20/46]) or RCA (8% [2/24]) groups. Lead aVR ST segment elevation was significantly higher in the LMCA group (0.16 +/- 0.13 mV) than in the LAD group (0.04 +/- 0.10 mV). Lead V(1) ST segment elevation was lower in the LMCA group (0.00 +/- 0.21 mV) than in the LAD group (0.14 +/- 0.11 mV). The finding of lead aVR ST segment elevation greater than or equal to lead V(1) ST segment elevation distinguished the LMCA group from the LAD group, with 81% sensitivity, 80% specificity and 81% accuracy. A ST segment shift in lead aVR and the inferior leads distinguished the LMCA group from the RCA group. In acute LMCA obstruction, death occurred more frequently in patients with higher ST segment elevation in lead aVR than in those with less severe elevation. CONCLUSIONS: Lead aVR ST segment elevation with less ST segment elevation in lead V(1) is an important predictor of acute LMCA obstruction. In acute LMCA obstruction, lead aVR ST segment elevation also contributes to predicting a patient's clinical outcome. (+info)
Clinical applications and outcomes of using indicators of risk in caries management.
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The aim of this review was to systematically assess clinical evidence in the literature to determine the predictive validity of currently available multivariate caries risk-assessment strategies (including environmental, sociodemographic, behavioral, microbiological, dietary/nutritional, and/or salivary risk factors) in: 1) primary teeth; 2) coronal surfaces of permanent teeth; and 3) root surfaces of permanent teeth. We identified 1,249 articles in the search, and selected 169 for full review. Inclusion and exclusion criteria were established prior to commencement of the literature search. Papers that conformed to these criteria were included (n = 15 for primary teeth; n = 22 for permanent teeth; and n = 6 for root surfaces), and 126 papers were excluded. Included articles were grouped by study design as: longitudinal, retrospective, and cross-sectional. The predictive validity of the models reviewed depended strongly on the caries prevalence and characteristics of the population for which they were designed. In many instances, the use of a single predictor gave equally good results as the use of a combination of predictors. Previous caries experience was an important predictor for all tooth types. (+info)
Higher order spatial correlations can capture edge and object relationships. Isotrigon textures are useful for studying our sensitivity to these correlations. We determined human discrimination performance for 18 isotrigon texture types and compared it with outputs from statistical discriminant models. Some of the models employed versions of the Allan Variance in receptive field outputs. Physiologically plausible mechanisms for such calculations are presented. Two discriminant models emulated human performance well, one based upon a global variance measure, and the other based upon a localised variance with an orientation bias. The 18 texture types were also shown to contain characteristic mini-textures. (+info)
Comparison of color-flow Doppler scanning, power Doppler scanning, and frequency shift for assessment of carotid artery stenosis.
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OBJECTIVE: We investigated the accuracy of color-flow Doppler (CD) scanning, power Doppler (PD) scanning, and peak systolic Doppler frequency shift (PSF) in assessment of carotid artery stenosis with angiography used as gold standard, including the measurement techniques used in the North American Symptomatic Carotid Surgery Trial (NASCET) and the European Carotid Surgery Trial (ECST). METHODS: Fifty-eight consecutive patients diagnosed for carotid artery surgery underwent color-coded duplex sonography and angiography. The duplex examination included the assessment of PSF and the videotaping of sagittal images in CD and PD mode from the proximal common carotid artery to the distal internal carotid artery. Two experienced examiners performed the studies, but once one examiner had done the taping, the other examiner was allowed only to review the tape. Separately, each examiner reviewed the tapes and determined by cursor settings each stenosis according to NASCET and ECST. For interobserver agreement kappa statistic was used. To compare with angiography (degree of stenosis 40%, 50%, 60%, 70%, and 80%) sensitivity, specificity, positive and negative predictive values, and overall accuracy were calculated. PSF cut-off frequencies were based on receiver operator curve analysis. RESULTS: Because interobserver agreement in CD and PD was good (chance-corrected kappa > 0.6), further analysis used the between-observer mean value for each stenosis. With the NASCET measurement technique, accuracy of Doppler techniques to distinguish a 50% stenosis was 89% for PSF, 91% for CD, and 93% for PD; for a 70% stenosis it was 83% for PSF, 84% for CD, and 81% for PD. With the ECST measurement technique, accuracy to distinguish a 70% stenosis was 86% for PSF, 88% for CD, and 86% for PD; for an 80% stenosis it was 87% for PSF, 87% for CD, and 77% for PD. CONCLUSION: CD and PD carotid artery stenosis measurements are highly reproducible, and in our hands provided accuracy equal to PSF. (+info)
Quantification of the expression level of the gene encoding the catalytic subunit of telomerase in testicular tissue specimens predicts successful sperm recovery.
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BACKGROUND: The objective of the present study was to evaluate the quantitative detection of human telomerase reverse transcriptase (hTERT) mRNA as a new molecular diagnostic parameter in the work-up of testicular tissue specimens from patients presenting with non-obstructive azoospermia. M ETHODS: hTERT mRNA expression was quantified in 49 cryopreserved testicular tissue specimens by fluorescence real-time RT-PCR in a LightCycler. This was paralleled by conventional histological work-up in all tissue specimens and additional semithin sectioning preparation in cases with maturation arrest (n = 20) and Sertoli cell-only syndrome (SCOS; n = 12). RESULTS: The average normalized hTERT expression (N(hTERT)) was 136.1 +/- 41.7 copies (mean +/- standard deviation) in tissue specimens with presence of haploid germs cells, N(hTERT) = 48.2 +/- 21.0 copies in those with maturation arrest and N(hTERT) = 2.7 +/- 2.8 copies in those with SCOS. The discriminant analysis showed that detection of N(hTERT) was able correctly to classify 89.0% of the investigated tissue specimens. CONCLUSIONS: Our results demonstrate that quantitative detection of hTERT mRNA expression in testicular tissue enables a molecular-diagnostic subclassification of spermatogenesis disorders. Quantitative detection of hTERT in testicular biopsies is thus well suited for predicting successful sperm recovery in patients with azoospermia and is a useful molecular diagnostic parameter for supplementing the histopathological evaluation. (+info)
A global measure of physical functioning: psychometric properties.
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OBJECTIVE: To examine the psychometric properties of a global physical functioning scale (GPFS) developed as a self-report measure and constructed to scale physical functioning from very poor (1) to excellent (100). DATA SOURCES: Data collection took place between January 1997 and September 1999. It consisted of self-ratings of surgical patients and the ratings of clinicians. The setting was the surgical department at a university hospital. STUDY DESIGN: Test-retest reliability and the convergence of the scores of patients and clinicians were examined in 106 patients before elective coronary or gastrointestinal surgery. Inter-rater reliability was tested in 36 hospitalized patients with cardiologic or vascular surgical diseases who were rated by random selection from a pool of 91 clinicians. The patients also rated their physical functioning. Discriminative validity, sensitivity to change, ceiling and floor effects, and influence of emotional state upon the scores were tested in 127 patients in six diagnostic groups who scored the GPFS before and subsequent to surgery. The concurrent validity was examined in 101 patients who scored the GPFS and the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) before elective coronary surgery. PRINCIPAL FINDINGS: The test-retest correlation (.90), correlation of the scores of the clinicians and patients (.87), and rater intraclass correlation coefficient (.82) were high. The GPFS discriminated among patients with different levels of physical functioning, and it was sensitive to change following coronary surgery. There were moderate ceiling and no floor effects. The correlation with the physical functioning scale of the SF-36 (PF-10) was .67. The GPFS differentiated patients with middle levels of physical functioning better than did the PF-10. CONCLUSIONS: The psychometric properties of the GPFS appeared adequate as a measure of general physical functioning. The scale is easy to use and also appears suitable for outcome studies following substantial changes in physical functioning as after coronary surgery. (+info)