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Abstract
This study examined whether Chinese and English orthographies would bring about a different Stroop effect. Eighty-five right-handed participants belonging to Chinese-English bilingual and English monolingual groups were invited to participate. The Stroop Color-Word Test - Victoria version (VST) and the Chinese version of the VST (CST) were the outcome measures. The bilinguals completed both the VST and CST, whereas the monolinguals performed only the VST. The results in both between- and within-group comparisons revealed no significant difference in Stroop effect no matter whether Chinese or English orthographies were used. This does not support the orthographic variation hypothesis and suggests that Chinese orthography does not generate a greater Stroop effect than English orthography.
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Abstract
The Color Trails Test (CTT) was developed as a culturally fair analogue of the Trail Making Test (TMT). This study examined the equivalence of these two tests for Chinese individuals in Hong Kong. One hundred and eight Chinese people volunteered for this study, and were classified into four groups according to their age and level of education. Their performance on these two tests was compared. The findings suggested that age and level of education indeed played significant roles in their performance on these two tests. Strong correlations (r = 0.72) were only observed between scores on Part B of the TMT and Part 2 of the CTT when the participants were older and had higher levels of education. This suggests that the equivalent construct of the Trail Making and Color Trails Tests can only be examined and established within specific age and education parameters.
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Chang CY, Chang LL, Chang YH, Lee TM, Li YH, Chang SF. Two new gene cassettes, dfr17 (for trimethoprim resistance) and aadA4 (for spectinomycin/streptomycin resistance), inserted in an Escherichia coli class 1 integron. J Antimicrob Chemother 2000; 46:87-9. [PMID: 10882694 DOI: 10.1093/jac/46.1.87] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Two new gene cassettes, dfr17 and aadA4, inserted in a class 1 integron of Escherichia coli EC107, are described here. The dfr17 cassette encodes trimethoprim resistance and has 91% identity with the dfrVII dihydrofolate reductase gene. The aadA4 cassette confers resistance to spectinomycin and streptomycin and shows 94% identity with the aadA3 gene. The integron carrying the dfr17 and aadA4 cassettes was located on a conjugative plasmid, pEC1072.
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Lee TM, Su SF, Tsai CC, Lee YT, Tsai CH. Cardioprotective effects of 17 beta-estradiol produced by activation ofmitochondrial ATP-sensitive K(+)Channels in canine hearts. J Mol Cell Cardiol 2000; 32:1147-58. [PMID: 10860759 DOI: 10.1006/jmcc.2000.1167] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have previously demonstrated the effects of estrogen on modulation of myocardial ATP-sensitive K(+)(K(ATP)) channel. Previous studies have demonstrated that activation of mitochondrial K(ATP)channel is a major contributor of ischemic cardioprotection. The purpose of the present study was to investigate the role of K(ATP)channel in estrogen-induced myocardial protection after ischemia/reperfusion in dogs. Anaesthetized dogs were subjected to 60 min of left anterior descending coronary artery occlusion followed by 2 h of reperfusion. In a first study to characterize effects of sex and the dose-response profile of estrogen on infarct size, the drug was intravenously administered at 10 or 20 microg/kg. In a second study to investigate the cardioprotective mechanisms of estrogen, vehicle, preconditioning or 17 beta -estradiol (10 microg/kg) was given, beginning 15 min prior to the 60 min occlusion period in the presence or absence of 5-hydroxydecanoate (5-HD). In the first study, administration of 17 beta -estradiol resulted in a significant, dose-dependent limitation of infarct size. Estrogen administration provided myocardial protection of similar magnitude in both males and females. In the second study, infarct size in control animals averaged 39+/-5% of the risk region, compared with 14+/-5% of the risk region in estrogen-treated dogs and 6+/-5% of the risk region in preconditioning dogs (both P<0.0001 v controls). Pretreatment with 5-HD completely abolished preconditioning- and estrogen-induced cardioprotection. Estrogen limits myocardial infarction size resulting from coronary artery occlusion and reperfusion in a dose-dependent fashion, irrespective of gender difference. The infarct size-limiting effect of estrogen++ was abolished by 5-HD, suggesting that the cardioprotective effect of estrogen may result from activation of myocardial mitochondrial K(ATP)channels.
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Lee TM, Chang E, Yang CY. A comparison of the surface characteristics and ion release of Ti6Al4V and heat-treated Ti6Al4V. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2000; 50:499-511. [PMID: 10756308 DOI: 10.1002/(sici)1097-4636(20000615)50:4<499::aid-jbm5>3.0.co;2-u] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This work seeks to investigate the nanosurface characteristics and ion release for a Ti6Al4V alloy prepared by various methods (as received and heat treated at 1300 degrees C for 2 h) with three different passivation treatments (34% nitric acid passivation, 400 degrees C heating in air, and aging in 100 degrees C deionized water). The surface and nanosurface composition are not related to the surface passivation treatments and experimental materials as evaluated by energy dispersive spectroscopy and X-ray photoelectron spectroscopy (XPS) analyses. After passivation and autoclaving treatments, the specimens were immersed in 8.0 mM ethylenediaminetetraacetic acid (EDTA) in Hank's solution and maintained at 37 degrees C for periods of time up to 16 days. The 400 degrees C treated specimens exhibit a substantial reduction in constituent release, which may be attributed to the thicker thickness and rutile structure of the surface oxides. After soaking in Hank's-EDTA solution, a significant time-related decrease in constituent release rate is observed for all kinds of specimens throughout the 0-16 day experimental period. The thicker oxides may be a factor in the improved dissolution resistance. Upon immersion, nonelemental Ca and P are both detected on the surfaces of all kinds of specimens by XPS analysis, and this could be explained by the existence of two types of hydroxyl groups (acidic and basic OH groups) on the oxide surface of the specimens.
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Hiebert SM, Thomas EM, Lee TM, Pelz KM, Yellon SM, Zucker I. Photic entrainment of circannual rhythms in golden-mantled ground squirrels: role of the pineal gland. J Biol Rhythms 2000; 15:126-34. [PMID: 10762031 DOI: 10.1177/074873040001500207] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Entrainment of circannual rhythms of body mass and reproduction was monitored for 3 years in female golden-mantled ground squirrels maintained in a simulated natural photoperiod. Both pinealectomized and pineal-intact squirrels generated circannual rhythms of body mass and estrus, but only the intact animals entrained these rhythms to a period of 365 days. In the second and third years after treatment, the period of the body mass rhythm was significantly shorter than 365 days for pinealectomized squirrels, and variance in tau among these animals was significantly greater than for intact squirrels. A similar pattern was evident in the rhythm of reproduction, which was phase-disrupted in pinealectomized squirrels but entrained in intacts. Seasonal changes in duration of nocturnal melatonin secretion by the pineal appear to be necessary to produce phase-delays required to entrain the circannual clock to a period of 12 months.
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Lee TM, Chan CC. Comparison of the Trail Making and Color Trails Tests in a Chinese context: a preliminary report. Percept Mot Skills 2000; 90:187-90. [PMID: 10769898 DOI: 10.2466/pms.2000.90.1.187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The Color Trails Test developed as a culturally fair analogue of the Trail Making Test, was used to examine the relationship between the two tests with 35 undergraduate Chinese in Hong Kong recruited as the subjects. The scores on these two tests of the 12 men and 23 women were significantly correlated .71. The equivalence of the Trail Making and Color Trails Tests when applied to Chinese in Hong Kong was discussed.
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Lee TM, Chang E, Yang CY. Effect of passivation on the dissolution behavior of Ti6A14V and vacuum-brazed Ti6A14V in Hank's ethylene diamine tetra-acetic acid solution Part I Ion release. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 1999; 10:541-548. [PMID: 15348105 DOI: 10.1023/a:1008916314329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This work aims to investigate the effects of three factors, namely: (1) two differently prepared materials (as-polished Ti6A14V and 2 h brazed Ti6A14V); (2) three different surface passivation treatments (34% nitric acid passivation, 400 degrees C heated in air, and aged in 100 degrees C de-ionized water); and (3) periods of immersion time (up to 32 days), on trace element release in Hank's ethylene diamine tetra-acetic acid (EDTA) solution. After passivation and autoclaving treatment, the specimens were immersed in 8.0 mM EDTA in Hank's solution and maintained at 37 degrees C for periods of time up to 32 days. The 400 degrees C -treated specimens exhibit a substantial reduction in constituent release, which may be attributed to the higher thickness and rutile structure of the surface oxides. For acid-passivated and water-aged treatments, a highly significant decrease in the trace levels of Ti, A1, and V is detected from the brazed Ti6A14V compared to those obtained from the Ti6A14V specimens. It is hypothesized that an anatase-rutile transformation of surface TiO_2 is likely to occur, accelerated by the elements of copper and nickel in the brazed specimens. In addition, a significant time-related decrease in constituent release rate is observed for all kinds of specimens throughout the 0-8 day experimental period. The implication of the results is discussed.
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Wang TD, Lee CM, Wu CC, Lee TM, Chen WJ, Chen MF, Liau CS, Sung FC, Lee YT. The effects of dyslipidemia on left ventricular systolic function in patients with stable angina pectoris. Atherosclerosis 1999; 146:117-24. [PMID: 10487494 DOI: 10.1016/s0021-9150(99)00108-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Large-scale clinical trials have shown that long-term treatment with lipid-lowering therapy results in a significant reduction in the occurrence of heart failure among patients with coronary artery disease without previous evidence of congestive heart failure, suggesting dyslipidemia may have an adverse effect on left ventricular performance. To examine whether dyslipidemia has a detrimental effect on left ventricular systolic function and whether this effect is dependent on the corresponding severity of coronary atherosclerosis, 114 consecutive patients with stable angina and a positive exercise thallium-201 myocardial perfusion single-photon emission computed tomography were studied. All patients underwent measurement of serum lipid profiles, right-sided heart catheterization, left ventriculography, and selective coronary arteriography. Mean serum levels of total cholesterol and triglycerides were 4.5 and 1.4 mmol/l, respectively. In univariate analysis, a significant positive correlation between serum high-density lipoprotein (HDL) cholesterol and left ventricular ejection fraction (LVEF) (r = 0.49, P<0.0001) was found. Patients in the lower tertile of serum HDL cholesterol had a significantly lower mean LVEF than those in the upper tertile (55.9+/-15.2 vs. 72.8+/-6.8%, P<0.0001). Stepwise multiple linear regression analysis revealed that LVEF significantly correlated with HDL cholesterol (P<0.0001), the Gensini score (P = 0.008), and diabetes mellitus (P = 0.08) (r = 0.55, P<0.0001). In subgroup analysis of patients with angiographically normal coronary arteries, serum HDL cholesterol was still significantly associated with LVEF. The present study demonstrated an independent association between low HDL cholesterol and subclinical left ventricular systolic dysfunction in Chinese patients with stable angina whose serum levels of total cholesterol and triglycerides were relatively low. Moreover, this correlation remained significant even in patients with normal coronary angiograms, suggesting HDL cholesterol might influence left ventricular systolic performance through extra-atherosclerotic mechanisms.
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Tsai CH, Lee TM, Su SF. Regression of ventricular repolarisation inhomogeneity after aortic bileaflet valve replacement in patients with aortic stenosis. Int J Cardiol 1999; 70:141-8. [PMID: 10454302 DOI: 10.1016/s0167-5273(99)00073-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND Aortic valve replacement relieves mechanical outflow obstruction in patients with aortic stenosis. However, there is limited information on whether aortic valve replacement can provide regression of ventricular repolarisation inhomogeneity. OBJECTIVES To determine whether aortic valve replacement can provide regression of ventricular repolarisation inhomogeneity in patients with aortic stenosis after bileaflet aortic valve replacement. METHODS We studied the changes of electrocardiographic QT or QTc intervals and QT or QTc dispersions of 71 patients with severe aortic stenosis and angiographically insignificant coronary lesions (<50% in diameter) before and after valve replacement (6+/-3 days after operation). Seventy-one healthy control subjects, matched for age and sex, served as control subjects. Twelve-lead electrocardiograms and echocardiographic examinations were measured before and after surgery. The QT interval was corrected for heart rate using the standard Bazett formula. QT dispersion was defined as the difference between maximal and minimal QT interval measurements occurring among any of the 12 leads on a standard electrocardiogram. QTc dispersion was calculated in a manner similar to QT dispersion. No subject had fewer than nine measurable leads. RESULTS Left ventricular systolic blood pressure, pressure gradient across aortic valve, left ventricular mass index, and systolic wall stress were significantly reduced after valve replacement compared with before valve replacement. The QT interval significantly decreased from 425+/-38 ms to 398+/-32 ms after replacement (P<0.0001). The QTc dispersion significantly decreased from 62+/-25 ms to 32+/-13 ms after replacement (P<0.0001). The value of QT or QTc dispersion after replacement was similar to that in controls. Univariate analysis revealed that QTc dispersion was significantly only correlated with left ventricular mass index (r=0.236, P=0.05). Multivariate analysis revealed that the best predictor of QTc dispersion was sex and left ventricular mass index (P=0.008 and 0.005, respectively). CONCLUSIONS Our study demonstrated a favorable consequence of aortic valve replacement distinct from hemodynamic improvement. Patients with aortic stenosis before valve replacement have abnormal prolonged QT or QTc intervals and increased QT or QTc dispersions. After successful valve replacement left ventricular mass index regressed and QT or QTc intervals and QT or QTc dispersions were normalized. These findings warrant further investigation in a large trial and long-term follow-up for clinical implications.
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Goel N, Lee TM, Smale L. Suprachiasmatic nucleus and intergeniculate leaflet in the diurnal rodent Octodon degus: retinal projections and immunocytochemical characterization. Neuroscience 1999; 92:1491-509. [PMID: 10426502 DOI: 10.1016/s0306-4522(99)00056-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The neural connections and neurotransmitter content of the suprachiasmatic nucleus and intergeniculate leaflet have been characterized thoroughly in only a few mammalian species, primarily nocturnal rodents. Few data are available about the neural circadian timing system in diurnal mammals, particularly those for which the formal characteristics of circadian rhythms have been investigated. This paper describes the circadian timing system in the diurnal rodent Octodon degus, a species that manifests robust circadian responses to photic and non-photic (social) zeitgebers. Specifically, this report details: (i) the distribution of six neurotransmitters commonly found in the suprachiasmatic nucleus and intergeniculate leaflet; (ii) the retinohypothalamic tract; (iii) the geniculohypothalamic tract; and (iv) retinogeniculate projections in O. degus. Using immunocytochemistry, neuropeptide Y-immunoreactive, serotonin-immunoreactive and [Met]enkephalin-immunoreactive fibers and terminals were detected in and around the suprachiasmatic nucleus; vasopressin-immunoreactive cell bodies were found in the dorsomedial and ventral suprachiasmatic nucleus; vasoactive intestinal polypeptide-immunoreactive cell bodies were located in the ventral suprachiasmatic nucleus; [Met]enkephalin-immunoreactive cells were located sparsely throughout the suprachiasmatic nucleus; and substance P-immunoreactive fibers and terminals were detected in the rostral suprachiasmatic nucleus and surrounding the nucleus throughout its rostrocaudal dimension. Neuropeptide Y-immunoreactive and [Met]enkephalin-immunoreactive cells were identified in the intergeniculate leaflet and ventral lateral geniculate nucleus, as were neuropeptide Y-immunoreactive, [Met]enkephalin-immunoreactive, serotonin-immunoreactive and substance P-immunoreactive fibers and terminals. The retinohypothalamic tract innervated both suprachiasmatic nuclei equally; in contrast, retinal innervation to the lateral geniculate nucleus, including the intergeniculate leaflet, was almost exclusively contralateral. Bilateral electrolytic lesions that destroyed the intergeniculate leaflet depleted the suprachiasmatic nucleus of virtually all neuropeptide Y- and [Met]enkephalin-stained fibers and terminals, whereas unilateral lesions reduced fiber and terminal staining by approximately half. Thus, [Met]enkephalin-immunoreactive and neuropeptide Y-immunoreactive cells project equally and bilaterally from the intergeniculate leaflet to the suprachiasmatic nucleus via the geniculohypothalamic tract in degus. This is the first report examining the neural circadian system in a diurnal rodent for which formal circadian properties have been described. The data indicate that the neural organization of the circadian timing system in degus resembles that of the most commonly studied nocturnal rodents, golden hamsters and rats. Armed with such data, one can ascertain differences in the functional organization of the circadian system between diurnal and nocturnal mammals.
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Lee TM, Su SF, Lee YT, Tsai CH. Effect of estrogen on ventricular repolarization in menopausal patients with syndrome X and effects of nicorandil. Am J Cardiol 1999; 84:65-9. [PMID: 10404853 DOI: 10.1016/s0002-9149(99)00193-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Syndrome X may exhibit myocardial ischemia and is associated with estrogen deficiency. We sought to assess the possible role of estrogen in modulating the characteristics of ventricular repolarization by measurement of QT interval and QT dispersion in patients with syndrome X. We prospectively used 12-lead electrocardiograms and echocardiograms to study 52 consecutive menopausal patients with syndrome X (group subdivided into subgroup 1a, 32 patients who received nicorandil, an adenosine triphosphate-sensitive potassium ion channel opener; subgroup 1b, 20 patients without dosing nicorandil). For comparisons, a control group consisted of age-matched and echocardiographic left ventricular mass index-matched 20 healthy menopausal women. Baseline QT intervals and QT dispersion were similar between the 2 groups (subgroup 1a and controls). After administration of estrogen, there was significant prolongation of maximal QTc intervals and reduction in QT or QTc dispersion compared with baseline in patients with syndrome X. The changes returned to baseline after nicorandil administration. Control subjects had no changes with administration of estrogen. Thus, estrogen modulates characteristics of ventricular repolarization, which appears to be mediated by blocking adenosine triphosphate-sensitive potassium ion channel. The effects of estrogen on QT intervals may be different between menopausal women with or without syndrome X.
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Abstract
OBJECTIVE The therapeutic effect of phototherapy for seasonal affective disorder (SAD) has been widely investigated. However, the antidepressant effect of various light intensities is inconclusive. The purpose of this study was to evaluate the dose-response relationship of phototherapy for SAD. METHOD A meta-analytical methodology was applied to 39 studies of phototherapy for SAD. The studies collected were screened for study quality by a threats-to-validity method before inclusion. The fixed-effects-model analysis of variance procedures were used for data analysis. RESULTS The results indicated that different light intensities produced different effects in reducing the typical symptoms, as measured by the Hamilton Depression Rating Scale, of patients with SAD. However, no significant differences in these effects were revealed between strong, medium and dim light in reducing the atypical symptoms of patients. CONCLUSION These findings showed that light intensity varied positively with the antidepressant effect for typical but not for atypical symptoms of SAD, suggesting that light intensity tended to have different therapeutic effects on the typical and atypical symptoms of SAD.
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Lee TM, Ho DS, Chan CC. Preliminary neuropsychological outcomes of angioplasty and stenting of extracranial cerebral arteries. Percept Mot Skills 1999; 88:267-70. [PMID: 10214653 DOI: 10.2466/pms.1999.88.1.267] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Preliminary evaluation of the neuropsychological status of three Chinese-speaking patients receiving angioplasty and stenting of extracranial cerebral arteries showed no significant decline in their performance on cognitive tasks measuring (1) memory function, verbal and nonverbal memory, (2) attention, and (3) cognitive processing speed. Although angioplasty and stenting of extracranial cerebral arteries did not appear associated with detrimental changes in the cognitive status of the two patients completing all cognitive tasks, their relation must be confirmed as a neuropsychologically safe measure for reducing the risk of stroke in Chinese with significant extracranial cerebral artery stenosis by a randomized controlled study with a much larger sample.
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Jiao YY, Lee TM, Rusak B. Photic responses of suprachiasmatic area neurons in diurnal degus (Octodon degus) and nocturnal rats (Rattus norvegicus). Brain Res 1999; 817:93-103. [PMID: 9889333 DOI: 10.1016/s0006-8993(98)01218-9] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Photic sensitivity of cells in the suprachiasmatic nuclei (SCN), the principal pacemaker of the mammalian circadian system, has been documented in several species. In nocturnal rodents, the majority of photically responsive SCN cells are activated by retinal illumination. One report identified mostly photic suppressions among SCN cells in a diurnal rodent, studied under somewhat different conditions. We examined photic sensitivity of SCN cells in a predominantly diurnal rodent, the degu, studied in vivo under identical conditions to rats, and found that a large majority of photic SCN cells were suppressed by light. In both rats and degus, SCN cells were more responsive to light during the subjective night than during the subjective day. Light-responsive cells did not show a daily rhythm in baseline firing rates in either species, but rat SCN cells that did not respond to light were more active spontaneously during the subjective day. Light-unresponsive SCN cells in degus did not show a similar pattern. There are substantial differences in the neurophysiological activity and photic responsiveness of SCN cells in diurnal degus and nocturnal rats.
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Abstract
This study pooled the demographic data reported in 40 studies on seasonal affective disorder to identify the ratio of men to women with this disorder. Among the 1129 subjects recruited for these 40 studies, women out-numbered men. A sex difference in biochemical responses to climatic variables was postulated as one of the possible explanations of the observed women's vulnerability to seasonal affective disorder.
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Tsai CH, Su SF, Lee TM. Association of increased QT dispersion with coronary atherosclerosis in patients with aortic stenosis. Int J Cardiol 1998; 66:267-74. [PMID: 9874079 DOI: 10.1016/s0167-5273(98)00240-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To evaluate correlates between electrocardiographic QT dispersion and coronary atherosclerosis in patients with aortic stenosis before aortic valve replacement, 39 consecutive patients >40 years old with symptomatic aortic stenosis and coronary diameter narrowing > or =50% measured by digital angiographic study were included. An additional matched group with insignificant coronary lesions (<50%) consisted of 39 patients for comparisons. Matching by age, sex heart rate and incidence of chest pain resulted in two comparable groups with identical baseline characteristics. Preoperative transthoracic echocardiography and electrocardiograms were performed in all subjects. QT dispersion was defined as the difference between maximal and minimal QT interval measurements occurring among any of the 12 leads on a standard electrocardiogram. No subject had fewer than nine measurable leads. There were no significant differences of risk factors of coronary artery disease between the two groups. From a conditional multivariate logistic regression analysis, independent predictors of development of coronary artery disease in aortic stenosis were only QTc dispersion (odds ratio= 1.255, P=0.01). A wide QTc dispersion > or =70 ins) correlated with the presence of angiographically significant coronary artery disease with a sensitivity and specificity of 72% and 79%. The positive accuracy of having significant coronary artery disease in the presence of QTc dispersion > or =70 ms was 78%. The negative predictive value was 74%. In conclusion, electrocardiographic QTc dispersion may provide important clinical information. A wide QTc dispersion in patients with aortic stenosis is associated with a high incidence of coronary artery disease. These findings warrant further investigation in a large trial.
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Williams MV, Baker DW, Honig EG, Lee TM, Nowlan A. Inadequate literacy is a barrier to asthma knowledge and self-care. Chest 1998; 114:1008-15. [PMID: 9792569 DOI: 10.1378/chest.114.4.1008] [Citation(s) in RCA: 427] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
STUDY OBJECTIVES To determine the relationship of literacy to asthma knowledge and ability to use a metered-dose inhaler (MDI) among patients with asthma. DESIGN Cross-sectional survey. SETTING Emergency department and asthma clinic at an urban public hospital. PATIENTS Convenience sample of 273 patients presenting to the emergency department for an asthma exacerbation and 210 patients presenting to a specialized asthma clinic for routine care. INTERVENTIONS Measurement of literacy with the Rapid Estimate of Adult Literacy in Medicine, asthma knowledge (20 question oral test), and demonstration of MDI technique (six-item assessment). MEASUREMENTS AND RESULTS Only 27% of patients read at the high-school level, although two thirds reported being high-school graduates; 33% read at the seventh- to eighth-grade level, 27% at the fourth- to sixth-grade level, and 13% at or below the third-grade level. Mean asthma knowledge scores (+/-SD) were directly related to reading levels: 15.1+/-2.5, 13.9+/-2.5, 13.4+/-2.8, 11.9+/-2.5, respectively (p < 0.01). Patient reading level was the strongest predictor of asthma knowledge score in multivariate analysis. Poor MDI technique (< or =3 correct steps) was found in 89% of patients reading at less than the third-grade level compared with 48% of patients reading at the high-school level. In multivariate regression analyses, reading level was the strongest predictor of MDI technique. CONCLUSIONS Inadequate literacy was common and strongly correlated with poorer knowledge of asthma and improper MDI use.
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Lee TM, Su SF, Wang TD, Wang WL, Chen MF, Liau CS, Lee YT, Tsai CH. Increased ventricular repolarization inhomogeneity during postural changes in patients with syndrome X. Am J Cardiol 1998; 82:615-20. [PMID: 9732890 DOI: 10.1016/s0002-9149(98)00410-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The interlead variation in QT interval (QT dispersion) can be used to assess regional inhomogeneity of ventricular repolarization under a variety of conditions, including stress. Patients with syndrome X may have increased sympathetic activity that could change QT interval regionally and give rise to an increase in QT dispersion under exercise testing. To test the hypothesis, 26 consecutive patients with syndrome X (group 1) were studied. Two additional groups matched in terms of age, sex, and left ventricular mass index consisting of 26 nonconsecutive patients with coronary artery disease (group 2) and 20 normal subjects (group 3) were studied for comparison. Standing induced a significantly higher increase of heart rate in group 1 than in groups 2 and 3 (7.5+/-6.0 vs 4.0+/-6.3 and 1.1+/-3.6 beats/min; p = 0.05 and 0.003, respectively). There were significant differences in QT dispersion between groups 1 and 2 on upright standing (48+/-12 vs 34+/-14 ms, p = 0.0003), but not at baseline (33+/-14 vs 38+/-11 ms, p = NS) or at peak exercise (38+/-9 vs 38+/-9 ms, p = NS). Results did not change when QTc dispersion was substituted for QT dispersion. From a conditional multivariate logistic regression analysis, the only independent predictor of occurrence of syndrome X on upright standing was QTc dispersion (odds ratio = 1.255, p = 0.01). Electrocardiographic QTc dispersion provides important clinical information. Patients with syndrome X had a higher increase of heart rate and QTc dispersion in response to standing from the supine position compared with patients with coronary artery disease and normal subjects.
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Lee TM, Chang E, Yang CY. Surface characteristics of Ti6Al4V alloy: effect of materials, passivation and autoclaving. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 1998; 9:439-448. [PMID: 15348856 DOI: 10.1023/a:1008815316564] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The properties of passivated films for Ti6Al4V alloy prepared by various methods (as-polished, brazed at 970 degrees C for 2 h and brazed at 970 degrees C for 8 h) were investigated. Four passivations (non-treated, nitric acid passivation, 400 degrees C-treated in air, and aged in boiling water), with or without autoclaving treatments, were adopted for evaluating the changes of surface properties, including chemical composition, chemical structure, and oxide thickness. From X-ray photoelectron spectroscopic (XPS) analyses, surface elements of copper and nickel in brazed samples were undetected for non-treated, acid-passivated and boiling water-aged specimens, while they were found in the 400 degrees C-treated specimen. The relative contents of Ti2++Ti3+ to Ti4+ were determined by passivation treatments, but were not related to the experimental materials and autoclaving treatment. Passivation and autoclaving decreased the Ti to Ti4+ ratio by virtue of an increase in oxide thickness. Of the four types of passivation treatment, the 400 degrees C thermal treatment exhibited the lowest content of suboxides and metallic elements and the thickest oxide by XPS analysis; however, this treatment may cause a desorption of the basic OH group in the hydration layer on the surface of titanium alloy.
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Lee TM, Chang E, Yang CY. A comparison of the corrosion behaviour and surface characteristics of vacuum-brazed and heat-treated Ti6Al4V alloy. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 1998; 9:429-437. [PMID: 15348855 DOI: 10.1023/a:1008863232494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The corrosion characteristics of the brazed Ti6Al4V specimens were analysed and compared with respect to the conventionally heat-treated specimens by an electrochemical corrosion test. The object of this research was to explore the potentiality of the brazed titanium for biomaterials. The characteristics of the 1300 degrees C heat-treated and the 970 degrees C brazed specimens, with passivation and sterilization treatment, were evaluated by measurement of corrosion potential, Ecorr, corrosion current densities, Icorr, polarization resistance of the reacted surface films, Rp, in a potentiodynamic test. The experimental results show that the corrosion rates of the heat-treated and the brazed samples are similar at Ecorr, and the value of Ecorr for the brazed sample is noble to the heat-treated samples. The passive current density of the brazed specimen is either lower or higher than the heat-treated specimen, depending on the polarization potential. By Auger electron spectroscopic and high-resolution X-ray photoelectron spectroscopic analysis on specimens from the potentiostatic test, the elements of copper and nickel in the brazing filler were not detected while less alumina was found in the reacted film of the brazed specimens when compared with the heat-treated specimens. The implication of the results is discussed.
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Goel N, Lee TM, Pieper DR. Removal of the olfactory bulbs delays photic reentrainment of circadian activity rhythms and modifies the reproductive axis in male Octodon degus. Brain Res 1998; 792:229-36. [PMID: 9593909 DOI: 10.1016/s0006-8993(98)00134-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The diurnal rodent, Octodon degus, exhibits robust sex differences in several circadian measures, including circadian period (tau) and reentrainment rates to photic and nonphotic (social) zeitgebers. The neural substrates underlying such physiological differences remain unknown. In female degus, olfactory bulbectomies (BX) inhibit socially-facilitated reentrainment, but do not alter photic reentrainment, entrained measures, or tau in constant darkness (DD). This experiment investigated the effects of BX in male degus on (i) photic reentrainment rates of circadian rhythms following a 6-h phase advance of the light-dark (LD) cycle; (ii) photic entrainment; (iii) tau of free-running activity rhythms in DD; and (iv) body weight, paired testis weight, and the reproductive hormones, testosterone, androstenedione and follicle stimulating hormone (FSH). BX significantly delayed photic reentrainment rates. They did not, however, modify tau, the phase of activity onset or offset, amplitude or duration (alpha) of the activity rhythm, mean daily locomotor activity levels, or body weight. FSH, testosterone and androstenedione were unaffected by BX, whereas paired testis weights were significantly greater in BX degus compared with shams. Thus, the olfactory bulbs influence photic reentrainment of circadian rhythms and modestly affect the reproductive axis in male degus. Our results suggest that the olfactory bulbs may be a neural source of observed sex differences in photic reentrainment in degus, and highlight interspecies variation in the olfactory bulbs' effects on entrained and free-running circadian rhythms and on reproduction.
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Lee TM, Su SF, Lin YJ, Chen WJ, Chen MF, Liau CS, Lee YT. Role of transesophageal echocardiography in the evaluation of patients with clinical pacemaker syndrome. Am Heart J 1998; 135:634-40. [PMID: 9539479 DOI: 10.1016/s0002-8703(98)70279-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVES The goal of this study was to investigate the possible role of transesophageal echocardiography in the evaluation of patients with clinical pacemaker syndrome. BACKGROUND Several reports on transthoracic echocardiographic features of ventricular pacing were described; however, no previous study of transesophageal echocardiography has been undertaken in patients at the severe end of pacemaker syndrome who need reprogramming of dual-chamber pacing for symptom relief. METHODS Twelve patients with ventricular-inhibited pacemakers (VVI) with clinical symptomatic pacemaker syndrome (group I) and 10 patients with VVI without pacemaker syndrome (group II) were prospectively studied. The two groups were pacemaker dependent and had persistent ventriculoatrial conduction. Transesophageal echocardiographic parameters were assessed in group II and within 6 hours before reprogramming to the DDD mode in group I. Follow-up transesophageal echocardiographic study was performed 28+/-5 days after reprogramming in group I. RESULTS All patients in group I had subjective improvements of symptoms after DDD reprogramming. The atrial reverse flow velocities of pulmonary veins in group I before reprogramming were significantly higher in group II (39.3+/-11.4 versus 15.7+/-13.5 cm/sec, p < 0.0001). Spontaneous echo contrast in the descending aorta was detected in all patients from group I before reprogramming. The prevalence of significant mitral regurgitation (> or = moderate) was significantly higher in group I before reprogramming than in group II (67% versus 8%, p = 0.01). Significant mitral regurgitation and spontaneous echo contrast in the descending aorta in group I disappeared after reprogramming to the DDD mode. CONCLUSIONS Transesophageal echocardiography provides physiologic, pacemaker-related hemodynamic changes in paced patients. Significantly higher atrial reverse flow velocities of pulmonary veins, increased frequency of spontaneous echo contrast in the descending aorta, and significant mitral regurgitation are peculiar echocardiographic findings in patients with VVI with clinical pacemaker syndrome.
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Hiebert SM, Lee TM, Licht P, Zucker I. Estradiol phase shifts circannual body mass rhythms of male ground squirrels. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:R754-9. [PMID: 9530243 DOI: 10.1152/ajpregu.1998.274.3.r754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Gonadectomized male golden-mantled ground squirrels (Spermophilus lateralis) were implanted with estradiol benzoate (EB)-filled or empty capsules. Body mass was monitored before, during, and for at least 1 yr after hormone treatment. EB treatment during the mass-gain phase of the annual cycle significantly decelerated increases in body mass; the period of the circannual rhythm (CAR) of body mass was 54 days longer in EB- than blank-treated squirrels. Hormone treatment during the mass-loss phase accelerated mass loss; although this effect only approached statistical significance, some phase markers of the CAR were significantly advanced in subsequent cycles. We conclude that, as in females, estradiol affects the waveform of the CAR of males differently at different phases of the circannual cycle. Sexual differentiation does not eliminate responsiveness of CARs of squirrels to estradiol; sex differences, if any, are subtle rather than absolute and, in this respect, differ from circadian rhythms.
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