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Biomedical subjects

E Lin

Publications and source records attributed to E Lin.

At least 55 records · Page 3Linked to original sources
PubMed2000

Effect of early emptying on quantitation and interpretation of liquid gastric emptying studies of infants and young children.

UNLABELLED: This study assesses the effect of emptying that occurs during feeding on quantitation and interpretation of liquid gastric emptying studies of infants and young children. METHODS: Forty-nine 99mTc-sulfur colloid liquid gastric emptying studies of 44 children (22 boys, 22 girls; mean age, 20 mo; age range, 2-46 mo) fed orally or by gastrostomy tubes were evaluated. Gastric residuals quantitated by 2 commonly used methods, the first of which does not account for early emptying and the second of which does, were compared. With the first method, residual relative to activity in the stomach at the start of imaging (Rg) was quantified by comparing activity in a region of interest (ROI) drawn about the stomach on the final image to activity in an ROI drawn about only the stomach at the start of imaging. With the second method, residual relative to total dose (Rt) was quantified by comparing activity in the same final ROI to activity in an ROI that included stomach and small bowel at the start of imaging. Studies were interpreted independently for Rg and Rt considering a value >70% as evidence of delayed emptying. RESULTS: Rt was lower than Rg by 15%-16% for the entire population, for patients fed orally, and for patients fed by gastrostomy tube. These differences reached statistical significance (P < 0.0001). In 31 of 49 studies, R1 was lower than Rg by > or =10%. In 8 studies, emptying classified as delayed on the basis of Rg was classified as nondelayed on the basis of Rt. Clinical decisions based on Rt did not require later management changes that would have indicated that treatment of gastric dysmotility had been postponed in any patient. CONCLUSION: Emptying that occurs during feeding should be factored into quantitation of liquid gastric emptying in infants and young children. Not recognizing and accounting for early emptying results in overestimated gastric residuals and can lead to classification of emptying as delayed in children whose residuals of the total administered dose are within a recognized range of normal.

Case-Control Studies↗
PubMed2000

Improved uniformity in tomographic myocardial perfusion imaging with attenuation correction and enhanced acquisition and processing.

UNLABELLED: Tissue attenuation results in nonuniform myocardial perfusion images with significant sex differences. New SPECT imaging protocols to correct attenuation are currently under investigation. This study was performed to assess the effects of attenuation correction (AC) on overall image uniformity compared with more conventional imaging protocols in both men and women. METHODS: Thirty-nine patients (19 men, 20 women) with less than a 5% likelihood of coronary artery disease were studied. (99m)Tc-sestamibi studies were acquired with a triple-head scanner equipped with a simultaneous transmission and emission protocol. Four imaging protocols were compared: a 180 degrees acquisition and filtered backprojection reconstruction (FBP), a 360 degrees acquisition and FBP, a 360 degrees acquisition and iterative reconstruction (IT), and a 360 degrees acquisition with IT and AC. Quantitative analysis was performed to evaluate myocardial tracer uniformity for men and women. RESULTS: 180 degrees, 360 degrees FBP, and 360 degrees IT showed sex differences, with decreased tracer concentration in the anterior wall in women and decreased tracer concentration in the inferior wall in men. AC images showed the greatest uniformity (9.9% coefficient of variation for AC versus 12.5% for IT, P < 0.0001), and no statistically significant differences in uniformity were seen between male and female AC studies. CONCLUSION: More uniform myocardial perfusion images were obtained with AC, resulting in images with no differences in uniformity between men and women. These techniques are expected to improve specificity and overall diagnostic accuracy.

Adult↗
PubMed2000

Reproducibility of renal length measurements with 99mTc-DMSA SPECT.

UNLABELLED: Renal length measurements are used in evaluating several abnormalities of the pediatric genitourinary tract. This study assesses reproducibility of renal length measurements obtained with 99mTc-dimercaptosuccinic acid (DMSA) SPECT. METHODS: The lengths of 98 kidneys of 51 children (age range, 1-16 y; mean age, 5.4 y) who underwent 99mTc-DMSA SPECT were measured independently by 2 observers. Renal length was calculated by converting pixels between points at the superior and inferior renal margins on a summated coronal image to centimeters. Lengths were measured for kidneys as they appeared in situ and after realignment along their long axes. SPECT reconstruction, choice of display parameters, positioning of points used for measuring, and alignment were performed independently by each observer. Interobserver variability, interobserver correlation, and mean differences between observers' measurements (expressed as measurement of observer 2 - measurement of observer 1) were calculated. RESULTS: Correlation between the observers' measurements was highly significant for both nonaligned and aligned studies (r = 0.95 and 0.97, respectively; both, P < 0.0001). Interobserver variability expressed as 1 SD was 3.6 mm for nonaligned studies and 2.8 mm for aligned studies. The mean difference between the 2 observers' measurements for nonaligned studies was 2.0 +/- 4.8 mm (P < 0.0001) with a range of -11 to 14 mm. For aligned studies the mean difference between the 2 observers' measurements was -0.1 +/- 4.0 mm (P = 0.88) with a range of -20 to 10 mm. Differences between observers were not dependent on absolute renal length (P = 0.68 for nonaligned studies; P = 0.40 for aligned studies). CONCLUSION: The variability in renal length measurements determined by 99mTc-DMSA SPECT is similar to that reported previously using sonography. Because the interobserver differences in renal length are similar to annual renal growth rates during childhood, caution should be applied when incorporating renal length measurements determined by 99mTc-DMSA SPECT into management algorithms. Additional studies are required to further establish interobserver variability, to assess intraobserver variability, and to evaluate means of improving standardization.

Adolescent↗
PubMed1999

Both lobes of the soluble receptor of the periplasmic histidine permease, an ABC transporter (traffic ATPase), interact with the membrane-bound complex. Effect of different ligands and consequences for the mechanism of action.

The histidine permease of Salmonella typhimurium is an ABC transporter (traffic ATPase). The liganded soluble receptor, the histidine-binding protein HisJ, interacts with the membrane-bound complex HisQMP2 and stimulates its ATPase activity, which results in histidine translocation. In this study, we utilized HisJ proteins with mutations in either of the two lobes and wild type HisJ liganded with different substrates to show that each lobe carries an interaction site and that both lobes are involved in inducing (stimulating) the ATPase activity. We suggest that the spatial relationship between the lobes is one of the factors recognized by the membrane-bound complex in dictating the efficiency of the induction signal and of translocation. Several of the key residues involved have been identified. In addition, using constitutive ATPase mutants, we show that the binding protein provides some additional essential function(s) in translocation that is independent of the stimulation of ATP hydrolysis, and one possible mechanism is proposed, which includes the notion that liganded HisJ has different optimal conformations for signaling and for translocation.

ATP-Binding Cassette Transporters↗
PubMed1999

Stepped collaborative care for primary care patients with persistent symptoms of depression: a randomized trial.

BACKGROUND: Despite improvements in the accuracy of diagnosing depression and use of medications with fewer side effects, many patients treated with antidepressant medications by primary care physicians have persistent symptoms. METHODS: A group of 228 patients recognized as depressed by their primary care physicians and given antidepressant medication who had either 4 or more persistent major depressive symptoms or a score of 1.5 or more on the Hopkins Symptom Checklist depression items at 6 to 8 weeks were randomized to a collaborative care intervention (n = 114) or usual care (n = 114) by the primary care physician. Patients in the intervention group received enhanced education and increased frequency of visits by a psychiatrist working with the primary care physician to improve pharmacologic treatment. Follow-up assessments were completed at 1, 3, and 6 months by a telephone survey team blinded to randomization status. RESULTS: Those in the intervention group had significantly greater adherence to adequate dosage of medication for 90 days or more and were more likely to rate the quality of care they received for depression as good to excellent compared with usual care controls. Intervention patients showed a significantly greater decrease compared with usual care controls in severity of depressive symptoms over time and were more likely to have fully recovered at 3 and 6 months. CONCLUSIONS: A multifaceted program targeted to patients whose depressive symptoms persisted 6 to 8 weeks after initiation of antidepressant medication by their primary care physician was found to significantly improve adherence to antidepressants, satisfaction with care, and depressive outcomes compared with usual care.

Antidepressive Agents↗
PubMed1999

Contour tracking using a knowledge-based snake algorithm to construct three-dimensional pharyngeal bolus movement.

Videofluorography (VFG) using a barium-mixed bolus is in wide clinical use for assessing patients with swallowing disorders. VFG is usually done with both lateral (LA) and anterior-posterior (AP) views, most commonly in two separate sittings. A real-time, three-dimensional (3-D) representation of the evolution of a pharyngeal bolus and its volumetric information can potentially help clinicians analyze and visualize the kinematics of swallowing, dysphagia, and compensatory therapeutic strategies. Active contour models, also known as "Snakes," have been used to solve various image analysis and computer vision problems. We applied a Snake algorithm to automate in part the contour tracking and reconstruction of VFG images to visualize and quantitatively analyze the 3-D evolution of a pharyngeal bolus. To improve the accuracy of the Snake search, we provided the additional "knowledge" of the pharyngeal image itself, which served as an extra constraint to push the Snake curve toward the desired contour. VFG of pharyngeal bolus transport in a normal subject was recorded by using barium-mixed boluses (viscosity: 185 centipoise, density: 2.84 g/cc) with volumes of 5, 10, and 20 ml. The resulting LA and AP video images were digitally captured and matched frame by frame. The knowledge-based Snake search algorithm was used to generate Snake points to satisfy both internal (i.e., smoothness) and external (i.e., boundary fitting) constraints. Using these Snake points, we traced the 3-D bolus movement at each time instant, assuming elliptic geometry in the cross-section of the pharyngeal bolus. By concentrating the 3-D images for each time instant, we developed a 3-D movie representing pharyngeal bolus movement. The efficiency, reproducibility, and accuracy of this algorithm in tracing pharyngeal bolus boundaries and estimating front/tail velocities were assessed and found satisfactory. We conclude that 3-D pharyngeal bolus movement can be traced both accurately and efficiently by using a knowledge-based Snake search algorithm.

Algorithms↗
PubMed1999

Sociodemographic, clinical, and attitudinal characteristics of the untreated depressed in Ontario.

BACKGROUND: Epidemiologic surveys consistently document high rates of untreated depression, yet why this unmet need exists is only partially understood. METHODS: We compared untreated depressed, treated depressed and "healthy" subjects on sociodemographic characteristics, need for treatment, and help-seeking attitudes using household survey data from Ontario, Canada (n = 9953). DSM-III R Major Depression was assessed by structured interview (UM-CIDI), and treatment was defined as seeking formal mental health care. Need for treatment was assessed using a broad array of clinical, disability, and risk measures. RESULTS: Depressed (treated and untreated) and "healthy" respondents differed significantly on nearly all comparative measures. However, the two depressed groups showed few sociodemographic or "need for treatment" differences. Notably, there were no significant clinical differences although the untreated did report less physical comorbidity (33.9% vs 60.0% treated depressed). There were, however, several attitudinal differences. Compared to the treated depressed, untreated respondents were less likely to feel they had a mental health problem (51.6% vs. 78.8%), to say they would seek help for a serious problem (36.6% vs 64.7%) or to feel comfortable consulting a professional (19.0% vs. 43.2%). LIMITATIONS: Because the data are cross-sectional, temporal relationships cannot be directly addressed. CONCLUSIONS: Despite appreciable morbidity, access to care by the untreated depressed may be hindered by their self-perceptions and greater discomfort with help-seeking. Lower physical comorbidity may also contribute through decreased health care contact and thus fewer opportunities for disclosing or detecting their illness.

Adolescent↗
PubMed1999

Voice target time in Parkinson's disease: A preliminary report.

A target-matching paradigm was developed to assess the vocal equivalents of reaction and movement time in Parkinson's disease. Six patients with Parkinson's disease and 6 age- and gender-matched control subjects were asked to enunciate /pa/ to reach a target frequency and intensity level in response to a light stimulus. The stimulus and acoustic responses were simultaneously recorded. Measures included laryngeal reaction time, time between stimulus and phonation onset; frequency voice target time, time from phonation onset to target level of frequency; and amplitude voice target time, time from phonation onset to target level of intensity. The 2 subject groups were significantly differentiated by laryngeal reaction time (t = 299.67, df = 10, P = 0.005) and frequency voice target time (t = 148, df = 10, P = 0.014). These data suggest voice target time is a viable tool for assessing the effects of neurologic disorders on voice execution in Parkinson's disease.

Adult↗
PubMed1999

Closed contour edge detection of blood vessel lumen and outer wall boundaries in black-blood MR images.

Quantitative measurements of the blood vessel wall area may provide useful information of atherosclerotic plaque burden, progression and/or regression. Magnetic resonance imaging is a promising technique for identifying both luminal and outer wall boundaries of the human blood vessels. Currently these boundaries are primarily defined manually, a process viewed as labor intensive and subject to significant operator bias. Fully automated post-processing techniques used for identifying the lumen and wall boundaries, on the other hand, are also problematic due to the complexity of signal features in the vicinity of the blood vessels. The goals of this study were to develop a robust, automated closed contour edge detection algorithm, apply this algorithm to high resolution human carotid artery images, and assess its accuracy, and reproducibility. Our algorithm has proven to be sensitive to various contrast situations and is reasonably accurate and highly reproducible.

Algorithms↗
PubMed1999

Photoglottographic measures in Parkinson's disease.

This study examines the usefulness of photoglottographic measures in reflecting the phonatory effect of Parkinson's disease. In the first experiment, data obtained by photoglottography were compared between 15 male patients with Parkinson's disease and 15 normal male speakers of similar age. Six photoglottographic parameters, mean open quotient (OQ), mean speed quotient (SQ), perturbation of open quotient (POQ), perturbation of speed quotient (PSQ), frequency perturbation ratio (FPR), and amplitude perturbation ratio (APR), in sustained vowel phonation were investigated. Increased SQ (t = -2.731, df = 28, P = 0.011) and POQ (t = -2.584, df = 28, P = 0.015) were significantly associated with data from patients in comparison to normal speakers. The FPR, APR, and OQ were not significantly different between normal subjects and patients. A follow-up experiment, including 12 female and 19 male patients with Parkinson's disease, was designed to evaluate the sensitivity of SQ and POQ in detecting vocal dysfunction. The sensitivity of SQ was found to be relatively high (93.5%), while that of POQ was low (45.2%). Methodological issues regarding the effects of gender, age, stage of the disease, and treatment on photoglottographic measures in Parkinson's disease were discussed.

Adult↗
PubMed1999

In charge but not in control: the management of teaching relationships by adults with low perceived power.

The paradoxical use of punitive force by adults with low perceived power was explored in teaching interactions. Punitive force was measured by the intensity of physical effort used in operating controls that displayed negative feedback to child trainees. Women who differed in perceived power were assigned to (a) situations in which they had high, low, or ambiguous control and (b) responsive, unresponsive, or ambiguously responsive children. Women with low perceived power--when given ambiguous control--were more likely than other women to (a) use high levels of punitive force and (b) show elevated levels of autonomic arousal. Arousal, in turn, partially mediated the relationship between perceived power and use of force. Women with low perceived power were also more likely to attribute intentionality to children whose behavior was ambiguous. Results were interpreted as having implications for violence within adult-child relationships.

Adult↗
PubMed1999

Biochemical analysis of a 5S rRNA-associated sub-particle from trypsinized eukaryotic ribosomes.

On limited trypsinization, eukaryotic ribosomes released sub-particles that comprised a 5S rRNA molecule and two peptides (a 32 kDa and a 14 kDa). By tryptic finger-printing and amino-terminal sequence analysis, these two peptides were determined to be derived from large subunit ribosomal protein L5 (rpL5). The 32 kDa peptide represents the rpL5 protein minus the amino terminal eight residues and the carboxyl terminal ends (approximately 21 residues), whereas the 14 kDa peptide comprised near the amino-terminal region. The time course of ribosome trypsinization revealed that the two peptides were released kinetically. The indicated that the amino and carboxyl terminal ends of rpL5 were the first to be hydrolyzed, suggesting that the two ends of the rpL5 protein were exposed on the surface of ribosomes. Exposure of the carboxyl-terminal end was confirmed by use of an anti-L5c antibody raised against the carboxyl terminal region of rpL5. The kinetic data also revealed that the nearby amino terminal region of rpL5 (represented by the 14 kDa peptide) was the last part of rpL5 to be hydrolyzed, which was considered to be the 5S rRNA binding site.

Animals↗
PubMed1999

Glottographic measures before and after levodopa treatment in Parkinson's disease.

OBJECTIVES: Investigate the usefulness of acoustic and glottographic measures for detecting effects of levodopa (L-dopa) treatment on vocal function of individuals with idiopathic Parkinson's disease. STUDY DESIGN: Compare recordings of vowels sustained at a target comfortable loudness level obtained before and after L-dopa treatment from 15 individuals with idiopathic Parkinson's disease showing signs of tremor. METHODS: A simultaneous acoustic, airflow, and electroglottographic recording technique was employed to record vowels phonated by subjects before and after L-dopa treatment. Algorithms were developed to derive from the recorded signal measures of fundamental frequency, SPL airflow rate, speed quotient (ratio of glottal opening to closing time time), and short- and long-term phonatory instability. A series of paired Student t tests or signed rank tests were performed to compare the pretreatment and posttreatment groups on these measures. RESULTS: Measures of speed quotient, acoustic shimmer (cycle-to-cycle amplitude perturbation), and the extent of tremor derived from acoustic intensity contours were found to significantly decrease after medication. Sound pressure level tended to increase after medication. The acoustic jitter (cycle-to-cycle frequency perturbation) and the extent of tremor derived from airflow signals did not significantly differentiate between premedication and postmedication voices. CONCLUSIONS: Objective measures of acoustic and electroglottographic signals are useful in monitoring the pharmacologic response of Parkinson's disease, reflecting decrease of laryngeal rigidity and short- and long-term acoustic amplitude fluctuation after L-dopa treatment.

Aged↗
PubMed1999

Patterns of care for depressed older adults in a large-staff model HMO.

The authors examined automated pharmacy and visit data for 502 members of a large-staff model health maintenance organization (HMO) who had been diagnosed with depression and started on antidepressants by their primary-care providers. Older patients (age >/=60; n=110) were less likely than younger adults (age 18-59, n=110) to receive adequate doses of antidepressant medications for 30 or 90 days. Older adults were also less likely than younger adults to receive more than two primary-care visits for depression in the 12 weeks after receiving a new antidepressant prescription and were less likely to receive specialty mental health care in the 6 months after receiving a new antidepressant prescription.

Adolescent↗
PubMed1999

Confronting the confounders: the meaning, detection, and treatment of confounders in research.

When one variable is studied to try to explain another, the relationship between them may be biased by a third variable. The bias, known as "confounding," is common and must be minimized in research. This description is deceptively simple, though. Identifying confounding is complex but can be reduced to a stepped procedure. By way of examples, this article describes confounding and how to recognize it.

Bias↗
PubMed1999

Mental health service use: a comparison of treated and untreated individuals with substance use disorders in Ontario.

OBJECTIVE: To determine the prevalence of and factors associated with mental health service use in the past year among respondents with an alcohol or other drug use disorder in a general population survey of Ontario adults. METHOD: Data were obtained from the 1990/1991 Mental Health Supplement to the Ontario Health Survey, which used the University of Michigan Composite International Diagnostic Interview (UM-CIDI). The current study examined 436 respondents aged 15-64 years who met Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) criteria for a substance use disorder in the past year. The 82 respondents who used services for a mental health or substance abuse problem during the past year were compared with the 354 nonusers. Illness severity, disability, health beliefs and attitudes, and predisposing or enabling factors were examined in bivariate and logistic regression analyses. RESULTS: Twenty-two percent of respondents used services in the past year. Having concurrent disorders (comorbidity), troubled relationships with others, and dysfunction in main activity, feeling comfortable talking to a professional about mental health problems, being older and an urban resident, not working or being in school, and having a biological parent with an alcohol or drug problem were all associated with service use. CONCLUSIONS: The results suggest that individual determinants, such as severity of illness, disability, attitudes, and predisposing or enabling variables, all have a role in predicting service use among individuals in the general population who suffer from alcohol and other drug disorders.

Adolescent↗