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Biomedical subjects

L J Lin

Publications and source records attributed to L J Lin.

At least 55 records · Page 3Linked to original sources
PubMed1992

Correlation between left ventricular systolic function and dipyridamole thallium SPECT redistribution patterns in coronary artery disease.

The dipyridamole thallium-201 single photon emission computed tomography (SPECT) and resting gated blood pool ventriculography were sequentially conducted in 31 consecutive patients with angiographically proven coronary artery disease. The functional significance of various thallium redistribution patterns was assessed. The patients with an entirely complete (CR) or partial (PR) redistribution pattern had a higher global left ventricular ejection fraction than those with combined PR and no redistribution (NR), while patients with an entirely CR pattern did not have a statistically better ejection fraction than those with PR. Furthermore, myocardial segments with normal perfusion (N) and those with CR or PR had a higher regional ejection fraction than those with NR in the infero-apical area and the septal area. The regional ejection fraction was statistically higher in patients with CR than in those with PR in the septal area and higher, though not statistically significant, in the infero-apical area. The functional difference between groups with N and CR was not significant. Thus, we conclude that the redistribution patterns of dipyridamole thallium SPECT are closely correlated with systole function. Myocardium, in the presence of redistribution, will have a better functional performance in coronary artery disease.

Adult↗
PubMed1991

Valerian-derived sedative agents. I. On the structure and spectral assignment of the constituents of valmane using the selective INEPT nuclear magnetic resonance technique.

The valepotriates, a group of chemically unstable iridoid triesters possessing sedative activity, contain various ester groups at the C-1, C-7, and C-11 positions. Using the selective INEPT NMR technique and employing a suitable polarization delay for long-range coupling, it was possible to achieve the assignment and location of the ester groups directly, without ambiguity, and without chemical modification. Six valepotriates isolated from Valmane tablets served as examples to demonstrate the utility of this NMR technique. During the course of this work, the "acevaltrate" fraction was shown to be a mixture of 1-alpha-acevaltrate (3) and 7-beta-acevaltrate (4), the structures of valtrate (1) and didrovaltrate (2) were confirmed directly, and two new valepotriates, 5a and 5b, were obtained as an inseparable mixture and characterized.

Carbon Isotopes↗
PubMed1991

The hospital course of acute myocardial infarction in the Tainan area.

The hospital records of 204 patients with acute myocardial infarction (AMI) admitted from August 1988 through July 1990 were reviewed. Of these, 138 patients who were admitted within 24 hours after onset of symptoms were enrolled in this retrospective study. In 138 patients (110 men, 28 women; aged 62.6 +/- 11.3 years), the mean prehospital time was 4.8 +/- 4.5 hours (median 3.0, range 0.5 to 24.0). Ninety-nine of these 138 patients were classified as an early presentation group (less than 6 hours); their mean prehospital time was 2.5 +/- 1.3 hours. Of these, 60 patients received thrombolytic therapy with intravenous streptokinase (SK), and their prehospital time was 2.3 +/- 1.2 hours, with mean time to SK therapy of 3.7 +/- 1.5 hours. The in-hospital mortality of these 60 patients was 16.7%. The remaining 39 patients, without SK therapy, had a higher in-hospital mortality (28.2%); their mean prehospital time was 2.7 +/- 1.3 hours. For the late presentation group (greater than or equal to 6 hours), the mean prehospital time was 10.6 +/- 4.3 hours and the in-hospital mortality was 7.7%. The frequency of severe congestive heart failure (Killip class III or IV) at admission was significantly higher in patients with early presentation, than with late presentation (30.7% vs 7.6%, p less than 0.05). The overall causes of death included congestive heart failure (79%), ventricular arrhythmia (8%) and underlying medical illness (13%). In conclusion, 43.4% of the AMI patients in this study received SK therapy, within a mean time of 3.7 +/- 1.5 hours after onset.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Ambulatory blood pressure in normal Chinese.

Noninvasive ambulatory blood pressure monitoring (NABPM) has been playing an increasing role in the diagnosis of hypertension and in the evaluation of antihypertensive drugs. NABPM data for the normal Chinese population has not yet been established. However, data obtained from 25 young male Chinese adults has been analysed. Average ambulatory blood pressure was 120 +/- 8/74 +/- 7 mmHg for the whole-day monitoring. There was an evident diurnal change of blood pressure during the 24-hour monitoring period with higher blood pressure levels being recorded during the daytime, rather than during the nighttime (7.8 +/- 9.7/4.4 +/- 4.8 mmHg; p less than 0.001). Maximal hourly blood pressure averages occurred during the late morning, while minimal hourly blood pressure averages occurred around midnight. The variability in blood pressure was 11 +/- 3/9 +/- 2 mmHg for the daytime and 11 +/- 3/8 +/- 2 mmHg for the nighttime. The incidence of abnormally high blood pressure ranged widely. Eating would raise both the systolic and diastolic blood pressure, while sleep caused a significant fall in blood pressure. This study offers basic data for the study of NABPM in young normotensive Chinese adults.

Adult↗
PubMed1990

Role of transesophageal echocardiography in detecting left atrial thrombus and spontaneous echo contrast in patients with mitral valve disease or non-rheumatic atrial fibrillation.

Instances of left atrial (LA) thrombus and spontaneous echo contrast were evaluated by both transthoracic echocardiography (TTE) and subsequent transesophageal echocardiography (TEE) in 50 patients with rheumatic mitral stenosis (Group I) and 52 patients with non-rheumatic atrial fibrillation (Group II). Among these 102 patients, TEE detected LA thrombi in 16 patients (15.7%) and spontaneous echo contrast in 35 (34.3%). In contrast, TTE revealed LA thrombi in only 8 patients (7.8%) and spontaneous echo contrast in only 2 patients (2.0%). All of the LA thrombi and spontaneous echoes detected by TTE were also found by TEE. When TEE was applied, patients with spontaneous echo contrast had a significantly higher incidence of LA thrombus than did those without this echo (42.8% vs 1.5%, p less than 0.01). Spontaneous echo contrast was coexistent in all but one of the patients with LA thrombi (15 of 16, 93.7%). In Group I, the incidence of spontaneous echo contrast for patients with isolated or predominant mitral stenosis was high (68.3%) when TEE was applied, but this echo was not observed in any patient who had more than a moderate degree of mitral regurgitation. In Group II, 7 patients (13.5%) were also found to have spontaneous echo contrast, which could only be detected by TEE. Of these 7 patients, LA thrombus was noted in 4 by TEE, but only in 1 by TTE. Thus, it can be concluded that: (1) TEE is superior to TTE for detecting LA thrombus and spontaneous echo contrast; (2) spontaneous echo contrast in LA is not only frequently encountered in mitral stenosis without significant mitral regurgitation, but is also found in some patients with non-rheumatic atrial fibrillation; and (3) the presence of spontaneous echo contrast is associated with a higher incidence of LA thrombus and may be considered as a warning sign for further formation of LA thrombus.

Adult↗
PubMed1989

Determination of stereo- and positional isomers of oxygenated triterpenoids by reversed phase high performance liquid chromatography.

Twenty four oxygenated triterpenoids, including eight pairs of stereoisomers and five pairs of positional isomers, could be separated by reversed phase HPLC. The capacity factors obtained in methanol-water and acetonitrile-water solvent systems made it possible to correlate the molecular polarities due to the presence of multiple oxygenated functional groups in these compounds. It was found that the number and position of functional groups as well as the stereochemistry of these functional groups played important roles in governing the polarity of these lanostanoid acids. The polarity weighting factors were in the following order: 3 beta-OH greater than 3 alpha-OH greater than 3 alpha-OAc greater than 3 beta-OAc. The contribution to polarity due to 15 alpha-OAc and 22 beta-OAc was probably very similar. The unique stereochemical character and eluting sequences of the lanostanoid acids provide information to generate empirical rules for predicting the role of individual polar functional groups in the chromatographic behavior in reversed phase HPLC.

Chromatography, High Pressure Liquid↗
PubMed1976

Evidence for a gonadotropin from nonpregnant subjects that has physical, immunological, and biological similarities to human chorionic gonadotropin.

Substances from urinary extracts of normal, nonpregnant subjects and human pituitary gonadotropin preparations were found to react similarly to human chorionic gonadotropin (hCG) in a radioimmunoassay system that is highly specific for hCG and without crossreactivity to human luteinizing hormone (hLH). The antiserum was produced in a rabbit immunized with a bovine albumin conjugate of the unique carboxyl-terminal peptide (residues 123-145) isolated from a tryptic digest of the reduced, S-carboxymethylated hCGbeta subunit. The antibody recognition site on the peptide was found to reside on the last 15 amino acid residues of the carboxyl-terminal peptide, as evidenced by the competitive binding activities against 125I-labeled hCG of a series of peptides chemically synthesized according to the carboxyl-terminal sequence of HCGbeta. In order to elucidate the nature of the crossreacting substance in urinary extracts, a human postmenopausal urinary preparation (Pergonal) and a kaolin-acetone extract of urine from a patient with Klinefelter's syndrome were subjected to gel chromatography on Sephadex G-100. The results indicate that fractions showing immunocrossreactivity with the antiserum to hCGbeta-carboxyl-terminal peptide coeluted with 125I-labeled hCG which was separated distinctly from hLH. The same fractions from this postmenopausal urinary gonadotropin preparation exhibited in vitro biological activity proportional to the immunocrossreactivity of the hCG-specific antiserum. Concentration of postmenopausal women's urine by acetone precipitation retained approximately five times more immunoreactivity per unit volume than kaolin-acetone extraction, when assayed with the antiserum to hCGbeta-carboxyl-terminal peptide.

Chorionic Gonadotropin↗