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Biomedical subjects

L C Lin

Publications and source records attributed to L C Lin.

At least 19 recordsLinked to original sources
PubMed2003

Triplet-to-singlet exciton formation in poly(p-phenylene-vinylene) light-emitting diodes.

The triplet to singlet exciton formation ratio in a MEH-PPV light-emitting diode is measured by comparing the triplet-induced absorptions with optical and electric excitations at the same singlet exciton density. The ratio is a strong universal decreasing function of the averaged electric field. Using 4 ns for singlet to triplet intersystem crossing time, the ratio is significantly larger than the spin-independent value 3 at intermediate field but is reduced to about 2 for higher field.

Journal Article↗
PubMed2001

Induction of cytochrome P450-dependent monooxygenase in mouse liver and kidney by rutaecarpine, an alkaloid of the herbal drug Evodia rutaecarpa.

Rutaecarpine is one of the main alkaloids of an herbal remedy, Evodia rutaecarpa, which has been used for the treatment of gastrointestinal disorder and headache. Effects of rutaecarpine on hepatic and renal cytochrome P450 (CYP)-dependent monooxygenase were studied in C57BL/6J mice. Treatment of mice with rutaecarpine by gastrogavage at 50 mg/kg/day for three days resulted in 57%, 41%, 6-, and 6-fold increases of hepatic microsomal benzo(a)pyrene hydroxylation, 7-ethoxycoumarin O-deethylation, 7-ethoxyresorufin O-deethylation, and 7-methoxyresorufin O-demethylation activities, respectively. However, the treatment had no effects on hepatic oxidation activities toward benzphetamine, N-nitrosodimethylamine, nifedipine, and erythromycin. In the kidney, rutaecarpine-treatment resulted in 2-fold and 42% increases of microsomal benzo(a)pyrene hydroxylation and 7-ethoxycoumarin O-deethylation activities, respectively. The treatment also increased renal 7-ethoxyresorufin O-deethylation activity to a detectable level. Immunoblot analysis of microsomal proteins showed that rutaecarpine-treatment increased the protein levels of CYP1A1 and CYP1A2 in the liver, whereas hepatic level of CYP3A-immunoreacted protein was not affected by rutaecarpine. These CYPs were not detectable in the immunoblot analyses of control and rutaecarpine-treated mouse kidney microsomes. These results indicated that rutaecarpine was a CYP1A inducer and showed potent inductive effects on both CYP1A1 and CYP1A2 in the liver.

Administration, Oral↗
PubMed2001

Development of a high-performance liquid chromatographic method for bioanalytical applications with sulpiride.

An improved HPLC method using a silica gel column with fluorescence detection (excitation at 300 nm and emission at 365 nm) was developed for the determination of sulpiride concentrations in plasma. Analysis of sulpiride in plasma samples was simplified by a one-step liquid-liquid extraction after alkaline treatment of only 1 ml of plasma. The low limit of quantitation was 20 ng/ml with a coefficient of variation of less than 20%. A linear range was found from 20 to 1500 ng/ml. This HPLC method was validated with the precision for inter-day and intra-day runs being 0.36-8.01% and 0.29-5.25%, respectively, and the accuracy (standard deviation of mean, SD) for inter-day and intra-day runs being -1.58 to 5.02% and -2.14 to 5.21%, respectively. Bioequivalence of the two products was evaluated in 12 normal healthy male volunteers in a single-dose, two-period, two-sequence, two-treatment cross-over study. Sulpiride plasma concentrations were analyzed with this validated HPLC method. Results demonstrated that the two tablet formulations of sulpiride appear to be bioequivalent.

Area Under Curve↗
PubMed2001

Inhibitory effect of evodiamine on aldosterone release by Zona glomerulosa cells in male rats.

Evodiamine is a bioactive alkaloid extracted from a Chinese herb named Wu-Chu-Yu, which possesses thermoregulatory, analgesic, and cardiovascular effects. Some studies have demonstrated that evodiamine reduces blood pressure through acting on endothelium and smooth muscle cells to produce a vasodilatory effect, but whether it affects aldosterone secretion is unclear. The purpose of this study was to examine the effect of evodiamine on aldosterone release in adrenal zona glomerulosa (ZG) cells. ZG cells were isolated from the adrenal glands of adult male rats and incubated with angiotensin II (Ang II, 1x10(-7) M) and 3H-pregnenolone in the presence or absence of evodiamine (1x10(-6)-1x10(-3) M) at 37 degrees C for one hour. The concentration of aldosterone in the media was measured by a radioimmunoassay. The level of radioactivity incorporated into aldosterone and its precursors after incubation of ZG cells with 3H-pregnenolone was analyzed by thin-layer chromatography. The results demonstrated that evodiamine decreased the basal level of and Ang II-induced release level of aldosterone in rat ZG cells. Administration of evodiamine also decreased the level of radioactivity incorporated into 3H-corticosterone and 3H-aldosterone following incubation of ZG cells with 3H-pregnenolone. This suggest that evodiamine affects aldosterone release in rat adrenal glomerulosa cells by acting on Ang II-associated pathway and reducing the activity of 11 beta-hydroxylase (an enzyme which coverts deoxycorticosterone to corticosterone) during the steroidogenesis of aldosterone.

Aldosterone↗
PubMed2001

Assessment of the myocardial changes in heart transplant recipients without evident acute myocardial rejection by integrated backscatter: comparison with simultaneous dobutamine stress echocardiography and (201)thallium spect.

Cardiomyocyte hypertrophy and interstitial fibrin deposition develop in cardiac allografts and contribute to the functional changes of transplanted hearts. We hypothesized that integrated backscatter (IBS) can detect these myocardial changes. A total of 32 heart transplant recipients with either no or mild acute rejection (International Society of Heart and Lung Transplantation grade IA) were enrolled in this study. IBS data of myocardium were collected immediately before simultaneous dobutamine stress echocardiography (DSE) and (201)thallium imaging. Coronary angiography and endomyocardial biopsy were also performed. Coronary angiography showed diffuse narrowing in 1 patient who also had abnormal results of IBS, DSE, and thallium results. In the other 31 patients with patent coronary arteries, there were 3 patients (10%) with abnormal DSE results, 19 patients (61%) with abnormal IBS patterns, and 16 patients (52%) with reversible thallium perfusion defects. Of the patients, 44% had cardiomyocyte hypertrophy and 56% interstitial fibrin deposition. There were significant differences in the prevalence of (201)thallium perfusion defects and serum cyclosporine levels between patients with and without abnormal IBS patterns. Pathologic changes were also associated with abnormal IBS patterns (p = 0.01). However, there was no association between abnormal IBS and DSE results. By multiple logistic regression analysis, the abnormal IBS patterns were associated inversely with serum cyclosporine level (p = 0.028). In conclusion, abnormal IBS patterns are associated significantly with perfusion heterogeneity and pathologic changes in heart transplant recipients without evident acute myocardial rejection. There is no association between abnormal IBS patterns and dobutamine-induced dyssynergy in these patients. IBS provides a noninvasive approach for detection of myocardial changes in transplanted hearts without evident acute rejection.

Cardiac Catheterization↗
PubMed2001

Accuracy of biphasic response, sustained improvement and worsening during dobutamine echocardiography in predicting recovery of resting myocardial dysfunction after revascularization: comparison with thallium-201 SPECT.

To evaluate the accuracy of various types of wall motion response during dobutamine echocardiography (DE) in predicting functional recovery after revascularization, we studied 30 patients with stable coronary disease and left ventricular dysfunction by simultaneous DE and (201)Tl reinjection SPECT. Among 480 segments (16 segments/patient), 199 had abnormal wall motion at baseline and 167 were revascularized. The predictive value for recovery of function was 72% for a biphasic response, 61% for sustained improvement, 77% for worsening, and 27% for no change (p < 0.01 vs. each). Biphasic response had a sensitivity of 40% and specificity of 85%. Combining biphasic, sustained improvement and worsening responses, the sensitivity, specificity and accuracy were 76%, 65% and 71%, respectively. For (201)Tl SPECT, they were 90%, 65% and 78%, respectively. Thus, a biphasic response alone is of low sensitivity. Combination of biphasic, sustained improvement and worsening responses gives an accuracy rate comparable to that of (201)Tl reinjection SPECT in assessing functional recovery.

Adult↗
PubMed2001

Alterations of myocardial ultrasonic tissue characterization by coronary angioplasty in patients with chronic stable coronary artery disease.

We conducted a study to delineate the alterations in the cyclic changes of myocardial ultrasonic integrated backscatter (IBS) in patients receiving angioplasty for chronic coronary artery disease. Ultrasonic tissue characterization (UTC) and dobutamine stress echocardiography were performed in 43 patients before and 24 h after angioplasty, as well as before the follow-up angiography 3 months later. For segments being normokinetic with ischemic burden, the blunted amplitude and increased nadir deviation of IBS cyclic modulation recovered soon after angioplasty. For dyssynergic segments with contractile reserve, the angioplasty rebuilt the amplitude before the wall motion recovered, but corrected the nadir deviation tardily. In both circumstances, the coronary restenosis abolished the initial restoration. Those nonviable segments persistently revealed large deviations and small weighted amplitudes irrelevant to coronary lesions. The progress of myocardial ischemia, the development of wall motion dyssynergy and, then, the loss of viability, show different patterns of alterations in UTC after alleviating coronary obstructions.

Aged↗
PubMed2001

Use of isomalto-oligosaccharide in the treatment of lipid profiles and constipation in hemodialysis patients.

Chronic constipation and hyperlipidemia, one of the many atherogenic risk factors, were common complications in hemodialysis (HD) patients. The present trial evaluates the therapeutic efficacy of isomaltose-oligosaccharide (IMO) in the treatment of chronic severe constipation and its effect on lipid profiles in 20 HD patients. After a 2-week basal period, these patients were allocated to receive 30 g of IMO for a 4-week period. After the study period, these patients were observed for another 4 weeks. Bowel frequency, gastrointestinal symptomatology, biochemical parameters, and lipid profiles were assessed. All patients completed this study. IMO induced a significant increase in number of bowel movements and hence improvement of constipation in 76.3% + 30.9% of patients during the 4-week treatment. Some, but well-tolerated gastrointestinal side effects were noted. Statistically significant decreases in total cholesterol and triglycerides (TG) and increases in high density lipoprotein-cholesterol (HDL-C) were noted after IMO treatment (P <.05 compared with baseline and controls). After the study period, those patients receiving IMO had reductions in levels of total cholesterol -17.6%, TG -18.4%, and elevations of levels of HDL-C by +39.1%. In conclusion, IMO once a day is well tolerated and effective in increasing bowel frequency and improving constipation in HD patients. In addition, IMO treatment was effective in lowering total cholesterol and triglycerides and in raising HDL-C in HD patients.

Adult↗
PubMed2001

Cytotoxic principles from Ventilago leiocarpa.

Three new anthraquinones, islandicin 4-methyl ether (1), 1,2,6-trihydroxy-7,8-dimethoxy-3-methylanthraquinone (2), and 2-hydroxyemodin 1-methyl ether (3) as well as two known triterpenoids [taraxerol (4), lupeol (5)], six anthraquinones [chrysophanol (6), islandicin (8), parietin (9), emodin (10), catenarin (11), skyrin (15)], a 2,3-dihydroflavonol [(+)-aromadendrin (12)], two benzisochromanquinones [ventiloquinone K (13) and ventiloquinone I (14)], and stigmasterol (7) were isolated from Ventilago leiocarpa. The cytotoxicity of these compounds to various tumor cell lines was evaluated, and compound 15 significantly suppressed growth of HeLa, Vero, K562, Raji, Wish, and Calu-1 tumor cell lines. With the exception of K562 cells, the proliferation of other tumor cell lines was inhibited by compounds 3 and 10.

Alkaloids↗
PubMed2001

Psychometrics of a Chinese translation of the swallowing questionnaire.

AIMS OF THE STUDY: The purpose of this study was to determine the psychometric properties of a Chinese version of a swallowing questionnaire. BACKGROUND/RATIONALE: Impaired swallowing may lead to serious complications if health care professionals do not accurately assess the problem and promptly intervene. The recognition of symptoms indicative of a swallowing problem is essential for nurses. The swallowing questionnaire could provide nurses with a valid instrument to assess patients' impaired swallowing. DESIGNS/METHODS: Phase I consisted of experts doing the initial translation into Chinese and back-translations of the questionnaire. Five experts then determined content validity of the Chinese version, and 35 bilingual subjects determined equivalence of the Chinese translation and English version. Phase II determined concurrent validity and internal consistency using 113 screened medical patients as subjects. Phase III used 105 screened long-term care subjects to determine construct validity. RESULTS/FINDINGS: In Phase I, rating on the appropriateness of items on the Chinese version yielding a content validity index of 0.988. The coefficient of equivalence between the Chinese and English versions of the instrument was 0.81, while per cent agreement for all items on the two versions ranged from 0.80--1.00. Phase II established internal consistency with a K-R20 of 0.74, and concurrent validity yielded a correlation between the swallowing questionnaire and the neurological swallowing exam of 0.675 (P < 0.01). Phase III determined construct validity with significant positive correlations found between the swallowing questionnaire and stroke history and masticatory ability. Significant negative correlations were found between swallowing and cognitive status, functional status and albumin. CONCLUSIONS: Although useful as a tool for nursing assessment and intervention, further work on the swallowing questionnaire such as conducting video fluoroscopy and a swallowing speed test, are recommended to further validate its accuracy.

Activities of Daily Living↗
PubMed2001

Dissociation of modular total hip arthroplasty at the femoral head-neck interface after loosening of the acetabular shell following hip dislocation.

Modular component dissociation is a potential problem of current modular total hip arthroplasty (THA) systems. We describe a case of dissociation of the modular THA at the femoral head-neck interface after loosening of the acetabular shell during closed reduction for posterior dislocation of THA. The causes of this dissociation and acetabular shell loosening are discussed. Successful treatment was provided with surgical revision of the acetabular and the femoral head components. The present case serves as a graphic reminder that the acetabular shell overhanging the acetabular bone must be avoided when implanting modular THA components.

Biomechanical Phenomena↗
PubMed2001

Leaf-specific upregulation of chloroplast translocon genes by a CCT motif-containing protein, CIA 2.

Chloroplasts are a major destination of protein traffic within leaf cells. Protein import into chloroplasts is mediated by a set of translocon complexes at the chloroplast envelope. Current data indicate that the expression of translocon genes is regulated in a tissue-specific manner, possibly to accommodate the higher import demand of chloroplasts in leaves and the lower demand of plastids in other tissues. We have designed a transgene-based positive screen to isolate mutants disrupted in protein import into plastids. The first locus we isolated, CIA2, encodes a protein containing a motif conserved within the CCT family of transcription factors. Biochemical analysis indicates that CIA2 is responsible for specific upregulation of the translocon genes atToc33 and atToc75 in leaves. Identification of CIA2 provides new insights into the tissue-specific regulation of translocon gene expression.

Amino Acid Motifs↗
PubMed2001

CTLA-4 gene polymorphism in promoter and exon-1 regions in Chinese patients with systemic lupus erythematosus.

Cytotoxic T lymphocyte associated antigen 4 (CTLA-4), a structural homologue of CD28, has been reported to be an important negative regulator of autoimmune diseases. Recent studies showed that CTLA-4 gene polymorphism was associated with several kinds of human autoimmune diseases, suggesting that CTLA-4 gene is probably a general susceptibility gene to autoimmune disease. The present study was conducted in Chinese to determine whether there is any association of the CTLA-4 gene polymorphism with the development of systemic lupus erythematosus (SLE). CTLA-4 gene polymorphism in promoter and exon 1 was detected by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method in 81 patients with SLE and 81 normal controls. The results showed that there were no statistically significant differences in both exon 1 and promoter gene polymorphism between SLE patients and normal controls. The preliminary study does not suggest an association of the known polymorphism in exon 1 and promoter of CTLA-4 gene with Chinese SLE. However, SLE is a very heterogeneous syndrome and CTLA-4 gene polymorphism might correlate with some specific clinical features. To exploring this possibility, subgroup analysis in more patients needs to be performed.

Abatacept↗
PubMed2001

Ventilatory defect in coal workers with simple pneumoconiosis: early detection of functional abnormalities.

Airway obstruction is a prominent feature in coal workers' pneumoconiosis (CWP). However, many patients with CWP have even demonstrated a normal forced vital capacity (FVC) and forced expiratory volume in 1s (FEV1). The purpose of this study was to evaluate the ventilatory defect by spirometry and search for parameters, other than FVC and FEV1, suitable for early detection of pulmonary impairment in CWP. A sample of 227 coal miners was selected from the medical clinics of two teaching hospitals. Maximal expiratory flow volume measurement and determination of functional residual capacity (FRC) and residual volume (RV) were carried out with an automated plethysmograph. The prevalence of airway obstruction (FEV1/FVC < 70%) in this sample of miners was 52.9% (120/227). There was a progression of functional impairment with the transition from category 0 to categories 2 and 3, no matter what the miners smoking habits. All of the 107 non-obstructed miners had a normal FVC and FEV1. However, the mean values for FEF25-75% (mean forced expiratory flow during the middle half of FVC) and Vmax50 (maximal expiratory flow rate at 50% FVC) were abnormally low, and RV was already elevated, in those non-obstructed subjects with category 1 simple pneumoconiosis. A borderline abnormally elevated FRC in the miners with radiological category 3 of CWP was also noted. We conclude that the Vmax50, FEF25-75%, and RV appeared to be the discriminative indices for detecting early ventilatory defect in non-obstructed patients with simple CWP. Further studies is still needed to clarify the cause of small airway dysfunction.

Adult↗
PubMed2001

Management of multiple level spondylolysis of the lumbar spine in young males: a report of six cases.

The most common procedure for surgical treatment of lumbar spondylolysis is intertransverse processes spinal arthrodesis with instrumentation. However, this procedure is associated with significant morbidity on long-term follow up. Direct repair of spondylolysis is an alternative method for preservation of motion segment and anatomic continuity in young adults with multiple level spondylolysis. From 1992 through 1998, six soldiers with a diagnosis of multiple level spondylolysis who complained of persistent low back pain were treated in our hospital. Spondylolysis involved two levels in five cases and three levels in one case. All patients underwent serial roentgenography of the lumbar spine and a staged pars interarticularis infiltration test with bupivacain 0.5%. Five patients underwent direct repair of the pars interarticularis defects with hook screws, translaminar screws, and bone graft, while one patient received conservative treatment. All surgically treated patients had either good or excellent results at a mean of 34.4 months follow-up. One patient who was treated nonsurgically still complained of sport restriction at 16 months follow-up. Direct repair of multiple pars interarticularis defects after a positive staged pars infiltration test can restore anatomic stability, relieve back pain, and preserve a greater range of motion of the lumbar spine in young patients with intact disc height.

Adult↗
PubMed2001

Superior mesenteric artery syndrome associated with hereditary motor and sensory neuropathy type II--a case report.

A 14-year-old girl with superior mesenteric artery (SMA) syndrome associated with hereditary motor and sensory neuropathy (HMSN) type II is reported. The initial presentations of HMSN type II were developmental delay and gait disturbance at 2 years of age. All deep tendon reflexes were absent. Nerve conduction velocities and left sural nerve biopsy all revealed axonal changes. Recently, she suffered from intermittent bilious vomiting and epigastralgia for 6 months. That caused body weight loss from 40 kg to 28 kg. Abdominal echography showed narrowed superior mesenteric artery angle. Upper gastrointestinal series revealed obstruction of third portion of duodenum. Accordingly, SMA syndrome was diagnosed. To the best of our knowledge, this case is the first report of SMA with HMSN type II in the world. When a child with chronic neurological disease presents with intermittent vomiting, SMA should be considered as a disease entity of differential diagnosis.

Adolescent↗
PubMed2000

Comparison of simultaneous dobutamine echocardiography and thallium-201 stress-reinjection single-photon emission computed tomography in predicting improvement of chronic myocardial dysfunction after revascularization.

Previous studies have shown that ultrasonic integrated backscatter is valuable in characterizing stunned myocardium. Recent investigations have demonstrated that resting cardiac cycle-dependent variation of integrated backscatter closely paralleled the contractile reserve in patients with chronic left ventricular ischemic dysfunction. The purpose of this study was to validate whether ultrasonic tissue characterization (UTC) compared with dobutamine stress echocardiography (DSE) and thallium-201 stress-reinjection single-photon emission computed tomography (Tl-SPECT) could predict reversible myocardial dyssynergy in patients with chronic coronary artery disease. Forty-eight patients with stable coronary artery disease underwent UTC, DSE, and Tl-SPECT simultaneously before successful coronary revascularization and were followed up with echocardiograms at rest >3 months later. Among the 58 investigated segments, the weighted amplitude, a composite parameter derived from the integrated backscatter power curve, was larger for those groups with greater functional recovery (p <0.001). For the persistent akinetic segments, the weighted amplitudes were small with large deviations of the nadir ratios that represented the asynchrony between the intramural contractile events and the global systole. Using the cut-off value 2.0 of the weighted amplitude, the sensitivity and specificity for predicting functional improvement after revascularization were both 82.8% (kappa = 0.66) and comparable to the sensitivity and specificity of DSE and Tl-SPECT. UTC, delineating the myocardial physical state and intramural contraction, can be a novel approach in predicting functional improvement of chronic dyssynergy after revascularization.

Adult↗