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PubMed2004

Automated segmentation of the left ventricle in cardiac MRI.

We present a fully automated deformable model technique for myocardium segmentation in 3D MRI. Loss of signal due to blood flow, partial volume effects and significant variation of surface grey value appearance make this a difficult problem. We integrate various sources of prior knowledge learned from annotated image data into a deformable model. Inter-individual shape variation is represented by a statistical point distribution model, and the spatial relationship of the epi- and endocardium is modeled by adapting two coupled triangular surface meshes. To robustly accommodate variation of grey value appearance around the myocardiac surface, a prior parametric spatially varying feature model is established by classification of grey value surface profiles. Quantitative validation of 121 3D MRI datasets in end-diastolic (end-systolic) phase demonstrates accuracy and robustness, with 2.45 mm (2.84 mm) mean deviation from manual segmentation.

Algorithms↗

PubMed2005

Electron energy loss spectra near structural defects in TiN and TiC.

In this study, we use first principles multiple scattering calculations on atomic clusters to show how the carbon and nitrogen K-edge fine structures are modified in the vicinity of structural defects in TiN and TiC. Changes in the electron energy loss spectra are due to changes in the atomic structure of the first atomic shells around the absorbing atom. Two different kinds of defects, which both modify the structure of these atomic shells, are investigated here. In a first part, we describe a method which correctly takes into account the statistical spatial distribution of nitrogen vacancies in a TiN cluster. We study the influence of vacancy concentration on the shape of the nitrogen K-edge spectra and we find that vacancies mainly affect the height of the second peak of the spectra. This peak decreases when the number of vacancies in the second nitrogen shell increases. In a second part, we study the carbon K-edge spectrum modification near stacking faults in TiC. Two different stacking faults are studied. These two-dimensional defects are responsible for changes in the position of the carbon as well as titanium atoms of the atomic shells centered on the absorbing carbon atom. The shape of the spectra is strongly modified near the stacking faults and several peaks are affected by these modifications. We show that these fine structure modifications only concern the very first carbon atomic layers near the two-dimensional defects.

Journal Article↗

PubMed2006

Dissociation between CSF total tau and tau protein phosphorylated at threonine 231 in Creutzfeldt-Jakob disease.

To study the potential diagnostic value of abnormally phosphorylated tau protein in Creutzfeldt-Jakob disease (CJD) compared to Alzheimer's disease (AD), we determined levels of tau phosphorylated at threonine 231 (p-tau231) and of total tau (t-tau) in cerebrospinal fluid (CSF) of CJD patients, AD patients, and healthy controls (HC). CJD patients showed excessively high t-tau levels but relatively low p-tau(231) concentrations compared to the AD group. t-tau alone yielded the best diagnostic accuracy to differentiate between CJD and AD patients, when compared to p-tau231 and the p-tau231/t-tau ratio (97, 78, and 95% correctly allocated cases, respectively). Our findings indicate a dissociation in the direction of change in CSF levels of t-tau and p-tau231 in CJD when compared to AD.

Age Distribution↗

PubMed2004

Parietal area VIP neuronal responses to heading stimuli are encoded in head-centered coordinates.

The ventral intraparietal area (VIP) is a multimodal parietal area, where visual responses are brisk, directional, and typically selective for complex optic flow patterns. VIP thus could provide signals useful for visual estimation of heading (self-motion direction). A central problem in heading estimation is how observers compensate for eye velocity, which distorts the retinal motion cues upon which perception depends. To find out if VIP could be useful for heading, we measured its responses to simulated trajectories, both with and without eye movements. Our results showed that most VIP neurons very strongly signal heading direction. Furthermore, the tuning of most VIP neurons was remarkably stable in the presence of eye movements. This stability was such that the population of VIP neurons represented heading very nearly in head-centered coordinates. This makes VIP the most robust source of such signals yet described, with properties ideal for supporting perception.

Action Potentials↗

PubMedDate not supplied

Clinical utility of coronary calcium scoring after nonischemic myocardial perfusion imaging.

BACKGROUND: Coronary artery calcium (CAC) scoring is increasingly being used after myocardial perfusion imaging (MPI) to detect preclinical coronary artery disease (CAD). However, there are few data to support this approach. METHODS AND RESULTS: We reviewed 200 consecutive patients without known CAD who were referred for CAC scoring shortly after nonischemic MPI. Of these, 13 (6.5%) had CAC scores greater than 400, indicating significant CAD; 22 (11%) had CAC scores of 101 to 400; 27 had CAC scores of 11 to 100; and the remainder (n = 138) has CAC scores of 1 to 10. Traditional risk factors and patient characteristics were not significant predictors of CAC scores of 101 or greater. However, age and the Framingham risk score were predictors of CAC scores greater than 0. At follow-up, significantly more patients with CAC scores of 101 or greater had been given the advice to take lipid-lowering medication and aspirin compared with those with CAC scores of 0. CONCLUSIONS: Of patients referred for CAC scoring after nonischemic MPI, 17.5% were identified as having CAD based on a CAC score greater than 100, allowing intervention with aggressive medical therapy. Patients who were reclassified were not easily identifiable by traditional risk factors, but Framingham risk score did predict the presence of CAC. Clinicians modified medical therapy based on the results of CAC scoring.

Age Distribution↗

PubMed2005

Multilevel analysis of couple congruence on pain, interference, and disability.

Couple congruence on ratings of pain severity and disability were examined using hierarchical linear modeling. Older community Individuals with Chronic Pain (ICPs) and their spouses completed the Multidimensional Pain Inventory (pain severity, interference, negative spouse responses to pain), Sickness Impact Profile (physical disability, psychosocial disability), and the Mood and Anxiety Symptom Questionnaire (psychological distress). Both spouses reported on ICPs' pain and disability as well as their own psychological distress. Spousal incongruence was observed on interference and physical disability such that ICPs reported greater disability than their spouses reported for them. No significant incongruence was observed in pain severity or psychosocial disability. Predictors of couples' mean ratings of pain and disability were identified. Specifically, couples in which the ICP was female reported higher couples' ratings of pain severity and interference. ICP distress was related to higher couples' ratings of all pain and disability variables whereas spouse distress was related to higher psychosocial disability ratings. ICPs' perceptions of negative spouse responses were also positively associated with couples' ratings of physical and psychosocial disability. In terms of congruence, ICP distress was associated with incongruence on interference, physical disability, and psychosocial disability whereas spouse distress predicted incongruence on pain severity, and interference. This study suggests that understanding couples' pain outcome ratings involves an awareness of factors that might influence their perceptions and behaviors.

Aged↗

PubMed2004

Process irregularity of cortisol and adrenocorticotropin secretion in men with major depressive disorder.

Although evidence suggests that major depressive disorder (MDD) is associated with hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis, research on basal HPA axis hormone levels in MDD patients has been inconclusive. Definitive characterization of basal cortisol and adrenocorticotropin (ACTH) secretion may be important for understanding the pathophysiology of this disorder. In recent years, a new approach to the analysis of basal hormone secretion has been developed involving the approximate entropy (ApEn) statistic, which represents the degree of disorderliness or serial irregularity in a time series of hormone levels. ApEn has been shown to reflect the degree of coordination in integrated network systems and has provided new insights into the pathophysiology of a number of endocrine conditions. In the study reported here, 15 medication-free men with MDD and 15 healthy control men were admitted to a General Clinical Research Center and had blood sampled for cortisol and ACTH determinations every hour over a 24-h period. The cortisol and ACTH time series were characterized with a cosinor analysis and with analysis of ApEn. Depressed patients and control subjects did not differ significantly on any parameter derived from the cosinor analysis or on several other standard indices of basal hormone secretion. However, the depressed men had significantly increased cortisol ApEn and significantly decreased ACTH ApEn compared with the healthy subjects. The ApEn findings suggest a loss of regulatory control over cortisol secretion, and possibly increased cortisol feedback on the pituitary in the depressed patients. Together, these results are most consistent with a primary abnormality of the adrenal gland and suggest that further investigation of adrenal gland physiology may be informative for the pathophysiology of depression.

Adrenocorticotropic Hormone↗

PubMed2005

Effects of radiotherapy on olfactory function.

BACKGROUND AND PURPOSE: Changes in olfactory function have been reported in patients receiving significant doses of radiation to the olfactory epithelium. Aim of this study was to investigate severity and time course of changes in olfactory function in patients irradiated for tumours of the head and neck region. MATERIAL AND METHODS: Forty-four patients receiving radiotherapy (RT) for tumours in the area of the head and neck participated (16 women, 28 men; age 11-81 y; mean 55 y). Olfactory function was measured before and bi-weekly during RT for 6 weeks. A subgroup (25 patients) was followed for 12 months. Patients were divided into two groups according to the dose to the olfactory epithelium. Twenty-two patients ('OLF group') had radiation doses to the olfactory epithelium between 23.7 and 79.5 Gy (median 62.2 Gy). In the 22 patients of the 'non-OLF group' the dose applied to the olfactory epithelium was significantly lower (2.9-11.1 Gy, median 5.9 Gy). Total tumour dose (30-76.8 Gy), age, sex distribution, and baseline chemosensory function were not significantly different between groups. Testing was performed for odour identification, odour discrimination, and olfactory thresholds. RESULTS: Odour discrimination, but not odour identification or odour threshold, was significantly decreased 2-6 weeks after begin of therapy in the OLF group. In addition, a significant effect of the radiation dose was observed for odour discrimination. More than 6 months after therapy, OLF group patients had significantly lower odour identification scores compared to the non-OLF group. CONCLUSION: As indicated through the non-significant change of olfactory thresholds, the olfactory epithelium is relatively resistant against effects of radiation. It is hypothesized that RT has additional effects on the olfactory bulb/orbitofrontal cortex responsible for the observed changes of suprathreshold olfactory function.

Adolescent↗

PubMed2005

Incidence and clinical features of delayed-onset infections after extraction of lower third molars.

OBJECTIVE: To describe the incidence and clinical features of delayed-onset wound infections after lower third molar extractions in an outpatient clinic. STUDY DESIGN: Retrospective forward study of 958 lower third molar extractions in the Oral Surgery and Implantology Department of the School of Dentistry of the University of Barcelona (Spain). RESULTS: Fourteen delayed-onset wound infections were recorded after suture removal (1.5% of the extractions). These infections usually developed 3-5 weeks after extraction. Half of the cases presented a radiolucency around the crown of the third molar. In most cases, ostectomy (13/14) and tooth sectioning (11/14) had been made. CONCLUSIONS: Delayed infections were a rare postoperative complication of lower third molars extractions. Nevertheless, patients should be warned that infection can still occur several weeks after the surgical procedure.

Adolescent↗

PubMed2006

Incidence of periapical lesions and clinical symptoms after pulpectomy--a clinical and radiographic evaluation of 1- versus 2-session treatment.

OBJECTIVE: Outcome of pulpectomy in 2 treatment sessions with calcium hydroxide as an intracanal dressing was compared to a procedure comprising instrumentation and root-filling in 1 session. STUDY DESIGN: Subjects with a vital pulp condition (N = 256) were recruited to a randomized clinical trial. Outcome parameters included radiographic signs of apical periodontitis and painful symptoms at clinical follow-ups 1 week and 1-3 years after treatment. RESULTS: Of 244 subjects available for final recall, 17 presented with periapical radiolucency. Lesions were evenly distributed among the 2 treatment groups. Postoperative pain recorded 1 week after permanent filling was significantly associated with overfilling (P = .001), with no difference between treatment groups. There was no association with presence of overfilling and radiographic lesion at end point of recall. CONCLUSIONS: Study confirms that pulpectomy may be carried out at a high rate of success if due attention is given to aseptic operating procedures, proper instrumentation and filling. Under these conditions an interappointment dressing with calcium hydroxide does not seem to influence outcome.

Adolescent↗

PubMed2005

Are examination findings important in screening for angina in the Malaysian patient?

BACKGROUND: The objective of this study is to look at how well patient history and examination findings can be used in screening for angina. METHODS: A total of 887 records were extracted from the electronic medical record system (EMR) in Selayang Hospital, Malaysia. The data was cleaned; 69 possible variables were extracted, and univariate and multivariate analyses were performed. RESULTS: From the univariate analysis, it was found that 19 variables are significantly associated with a diagnosis of angina. However, multiple logistic regression reveals that only 11 of these 19 variables are significantly related to a diagnosis of angina. Chest pain aggravated by exertion, history of diabetes mellitus, and history of heart disease (regardless of whether on treatment or not) are significant predictors of angina. Sudden onset chest pain, pain that is persistent, pain relieved by other means, pain aggravated by inspiration, and findings of rhonchi are important predictors of a diagnosis other than angina. The degree of overall accuracy is high at 71.3%. There are eight factors which are significant in the univariate analysis but are not significant in the multivariate analysis. These are marital status, pain relieved by glyceryl trinitrate (GTN), pain relieved by rest, associated nausea, pain aggravated by posture, pain aggravated by cough, history of hypertension, and history of smoking. CONCLUSIONS: These findings suggest that examination findings do not play a significant role in screening for angina.

Adult↗

PubMed2004

Gender differences in knowledge of stroke in patients with atrial fibrillation.

BACKGROUND: A limiting factor for immediate initiation of stroke therapy is delayed hospital arrival. We assessed general knowledge on and behavior during an acute stroke with particular emphasis on prehospital temporal delays and a focus on the high-risk group of patients with atrial fibrillation (AF). METHODS: As part of the Berlin Acute Stroke Study (BASS), we interviewed patients admitted to hospital with symptoms of stroke using a standardized questionnaire. Cardiac rhythm was assessed by ECG and Holter monitor. Data analysis included additional stratification for age and gender. RESULTS: Of a total of 558 patients (66.8 +/- 13.5 years; 45% female) diagnosed with TIA or stroke 28% interpreted their own symptoms correctly as due to stroke. Female patients reporting cardiac arrhythmias and having AF more often correctly interpreted their symptoms as stroke (P = 0.03), considered their symptoms urgent (P = 0.02), considered stroke a medical emergency (P < 0.05) and had shorter prehospital delay times (P = 0.001) compared to female patients not reporting cardiac arrhythmias. Male, younger (< 65 years) and older patient groups showed no such effect, respectively. CONCLUSION: Females who know to have AF demonstrate better knowledge of stroke symptoms compared to females unaware or without this risk factor. This better knowledge translates into more appropriate behavior during an acute stroke.

Age Distribution↗

PubMed2004

The harm done by tests of significance.

Three historical episodes in which the application of null hypothesis significance testing (NHST) led to the mis-interpretation of data are described. It is argued that the pervasive use of this statistical ritual impedes the accumulation of knowledge and is unfit for use.

Accidents, Traffic↗

PubMed2003

Prevalence of self-reported heart failure among US adults: results from the 1999 National Health Interview Survey.

OBJECTIVE: The objective of the present study was to determine the prevalence of self-reported heart failure among US adults. METHODS: Data from the 1999 National Health Interview Survey were analyzed. A total of 30,801 sampled adults aged >or=18 years were given a list of major medical conditions, which included heart failure (HF), and asked if they had ever been told by a doctor or other health professional that they had any of the conditions. Analyses were conducted with the use of SUDAAN software to account for the complex sample design. RESULTS: An estimated 2.4 million adults had been told by a doctor or other health professional that they had HF. The prevalence of self-reported HF for age groups 18 to 39, 40 to 64, 65 to 74, and 75 to 105 years were 0.1%, 1.1%, 3.6%, and 5.5%, respectively. HF was most prevalent among ever-smokers, obese persons, and persons aged >or=65 years. No difference was found in the prevalence of self-reported HF between black and white persons. The most common comorbid conditions for those with HF were hypertension, coronary heart disease, and diabetes. Compared with those without HF, the elderly persons with HF were 8 times as likely to have severe mobility difficulties and 2 to 3 times as likely to have severe depression. Half of the elderly persons with HF had been hospitalized, visited an emergency room, or had >10 clinic visits in the past year. Black patients were more likely than white patients to have been unable to pay for prescription medicine and to have seen a medical specialist during the past year. CONCLUSIONS: This nationally representative survey indicates that an estimated 2.4 million adults had been told by a doctor or other health professional that they had heart failure. Black patients with HF were less likely than white patients to have received the needed care.

Adult↗

PubMed2002

Risk factors for nephrolithiasis in patients with familial idiopathic hypercalciuria.

PURPOSE: About 40% of patients with nephrolithiasis have idiopathic hypercalciuria, sometimes associated with a family history of kidney stones. In these families, little is known about the frequency of, and risk factors for, stone formation among hypercalciuric patients. We therefore conducted a prospective study of 216 subjects from 33 families with idiopathic hypercalciuria. MATERIALS AND METHODS: We recorded the age, weight, and history of calcium stones in all subjects, and measured 24-hour urine volume and excretion of calcium, uric acid, sodium, magnesium, urea, citrate, phosphate, and sulfate on a nonrestricted diet. We performed a more complete metabolic evaluation in many of the hypercalciuric subjects (calciuria/weight >0.1 mmol/kg/d). Multivariate logistic regression analysis was performed to identify independent risk factors for stone formation. RESULTS: The prevalence of self-reported nephrolithiasis was 46% (61/132) in hypercalciuric subjects and 11% (7/63) in normocalciuric subjects (P <0.0001). In multivariate analysis, age (odds ratio [OR] per 10 years of age = 1.3; 95% confidence interval [CI]: 1.1 to 1.6), urine calcium excretion (OR = 1.3 per mmol/d increase; 95% CI: 1.2 to 1.5), and uric acid excretion (OR = 3.3 per mmol/d increase; 95% CI: 1.4 to 7.5) were independent risk factors for nephrolithiasis. The risk of nephrolithiasis increased progressively with greater levels of hypercalciuria. CONCLUSION: We found a significant dose-effect association between calciuria and stone disease in patients with familial hypercalciuria. Other factors associated with stone formation included higher uric acid excretion, probably reflecting higher food intake, and age, probably reflecting the length of exposure to hypercalciuria and hyperuricosuria.

Adult↗

PubMed2002

Dissociation of hospitalization and mortality trends for myocardial infarction in the United States from 1988 to 1997.

PURPOSE: Although age-adjusted mortality from myocardial infarction in the United States has declined during the past few decades, changes in the incidence of myocardial infarction are less certain. To address this issue, we evaluated trends in hospitalization for, and in-hospital mortality from, myocardial infarction from 1988 to 1997. METHODS: Hospitalization rates were determined by age and sex using data from the National Hospital Discharge Survey and the Current Population Survey. Comorbid conditions, complications, use of cardiac procedures, and in-hospital mortality were measured. In-hospital mortality was estimated after adjusting for associated risk factors, complications, use of invasive diagnostic and therapeutic procedures, and length of stay. RESULTS: Age-adjusted rates of hospitalization for myocardial infarction were 525 per 100,000 in 1988 and 482 per 100,000 in 1997, with a mean annual decline of 0.8% (P = 0.32). Mortality declined from 58 per 100,000 in 1988 to 40 per 100,000 in 1997, a mean annual decline of 4.2% (P = 0.01). During these 10 years, although the median hospital stay for myocardial infarction decreased from 8 to 5 days, the intensity of hospital care increased, including use of angiography from 20% to 31% (P = 0.04) and revascularization from 16% to 31% (P = 0.004). Age-adjusted in-hospital mortality decreased by nearly half, from 7.6% in 1988 to 3.9% in 1997 (P = 0.006). CONCLUSION: During the past decade, the decline in mortality from myocardial infarction in the United States has not been accompanied by a decline in hospitalization rate. At the same time, there has been a marked increased in the use of cardiac revascularization.

Adult↗

PubMed2003

The incidence of dysphagia in pediatric patients after open heart procedures with transesophageal echocardiography.

BACKGROUND: Pediatric patients who undergo open heart operations may be at risk for the development of dysphagia because of interventions such as intubation and transesophageal echocardiography. Although the occurrence of dysphagia after cardiac surgical procedures in adults is reported to be 3% to 4%, the incidence in children and adolescents has not been documented. This study was undertaken to determine the incidence of and risk factors contributing to dysphagia in pediatric patients after open heart procedures. METHODS: Fifty patients were evaluated after open heart operations with transesophageal echocardiography between March 1, 1999, and September 30, 1999. The diagnosis of dysphagia was made by a speech pathologist using a clinical swallowing evaluation. Potential predictors examined included demographic variables, anatomical diagnosis, surgical procedure, size of the transesophageal echocardiographic probe in relation to body size, length of probe insertion time, preoperative patient acuity status, duration of intubation, and time until discharge. RESULTS: Dysphagia was found in 9 (18%) of the 50 patients. Risk factors identified were age of less than 3 years (odds ratio, 20.4; 95% confidence interval, 2.7 to 157; p = 0.002), intubation prior to operation (odds ratio, 17.7; 95% confidence interval, 9.4 to 210; p = 0.004), intubation for more than 7 days (odds ratio, 74.7; 95% confidence interval, 13.8 to 405; p = 0.001), and operation for left-sided obstructive lesions (odds ratio, 1.9; 95% confidence interval, 2.2 to 8.3; p = 0.038). The size of the transesophageal echocardiographic probe in relation to the weight of the patient was found to be predictive (p = 0.0001) of dysphagia. Vocal cord paralysis was noted in 4 (8%) of the 50 patients postoperatively. Adverse events related to aspiration occurred in 2 patients (4%). At discharge, nasogastric tube feedings were required in 6 patients (12%), and thickened feedings were recommended for 3 (6%) of the 50 patients. Resolution of dysphagia ranged from 13 to 150 days. CONCLUSIONS: Eighteen percent of patients had dysphagia after an open heart operation with transesophageal echocardiography. Age of less than 3 years, preoperative patient acuity status, longer intubation times, and operation for left-sided obstructions are risk factors for dysphagia in this cohort of pediatric patients. The size of the transesophageal echocardiography probe in relation to the patient's weight was predictive of dysphagia. Physicians should consider using the new mini-multiplane transesophageal echocardiographic probes in patients weighing less than 5.5 kg. Vigilance in monitoring for the signs of preoperative and postoperative dysphagia with prompt referral to a speech therapist can substantially reduce patient morbidity, length of hospital stay, and requirement of prolonged nasogastric tube use.

Adolescent↗

PubMed2003

Periodic pharyngolaryngoscopy detects early head and neck cancer and improves survival in esophageal cancer.

BACKGROUND: Multiple squamous cell carcinomas (SCCs) frequently arise in the upper aerodigestive tract. The purposes of this study were to identify risk factors for SCC of the head and neck in patients with esophageal cancer (EC) and to investigate the value of periodic pharyngolaryngoscopic screening in detecting early SCCs of the head and neck and improving survival. METHODS: We reviewed the cases of 754 patients with EC treated surgically (n = 545) or nonsurgically (n = 209) from May 1995 to December 1999 in our institution. Of these patients, 541 underwent periodic pharyngolaryngoscopic screening after treatment of EC, whereas 213 did not because of hospital death, dropout from the program, and distance from the hospital. Data were compared between patients in whom SCCs of the head and neck developed synchronously or metachronously (EC + SCC group, n = 70) and patients without SCCs (EC group, n = 684). Survival rates were compared between patients receiving periodic pharyngolaryngoscopy and those followed without endoscopic screening. RESULTS: In the EC + SCC group, younger patients (p < 0.05), male patients (p < 0.05), and patients with a higher alcohol intake (p < 0.01) were more common than in the EC group. The 5-year survival rate was 40.9% in the EC group and 44.8% in the EC + SCC group (p = not significant). The survival rate of patients receiving periodic pharyngolaryngoscopy was significantly higher than that of patients followed without endoscopic screening (p < 0.001). Periodic pharyngolaryngoscopy was effective in detecting early SCCs of the head and neck and was beneficial for patients with EC in stages I to IV. CONCLUSIONS: Periodic pharyngolaryngoscopy can provide early detection of SCCs of the head and neck, which arose in 9.3% of patients with EC. Such screening particularly benefits male patients and heavy drinkers, who are at high risk for multiple SCCs. Periodic pharyngolaryngoscopy may prevent reduced survival resulting from associated SCCs of the head and neck and improve overall survival in patients with EC.

Age Distribution↗

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