Biomedical subjects

H M Lin

Publications and source records attributed to H M Lin.

At least 19 recordsLinked to original sources

PubMed2006

Protective effects of Ligustrum lucidum fruit extract on acute butylated hydroxytoluene-induced oxidative stress in rats.

Nuzhenzi, the fruit of Ligustrum lucidum Ait. (Oleaceae), is commonly used as tonic for kidney and liver in the traditional Chinese medicine prescription. The present study aimed to investigate the antioxidant activities of ethanol extract of Ligustrum lucidum fruits (ELL) and its effects on butylated hydroxytoluene (BHT)-induced oxidative stress in rats. Results showed that ELL possesses weak antioxidant activities. Compared to the BHT (1000mg/kg)-treated group, results showed that ELL at 250, 500 and 1000mg/kg significantly reduced the levels of blood urea nitrogen (BUN), serum glutamic pyruvic transaminase (sGPT), glutamic oxaloacetic transaminase (sGOT), alkaline phosphatase (sALP), lactate dehydrogenase (LDH), triglyceride (TG) and creatinine (Cr), as well as LDH in bronchoalveolar lavage fluid (BALF). It also significantly decreased the level of lipid peroxides in liver and lung. In addition, ELL significantly enhanced the levels of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) in these organs. Histopathological evaluation of the tissues revealed that ELL reduced the incidence of lung lesions, while the liver and kidney tissues were not affected by BHT administration. Taken together, the protective effect of ELL against acute BHT-induced oxidative stress in rats could be through the upregulation of antioxidant enzymes.

Animals↗

PubMed2006

Daytime napping after a night of sleep loss decreases sleepiness, improves performance, and causes beneficial changes in cortisol and interleukin-6 secretion.

Sleep loss has been associated with increased sleepiness, decreased performance, elevations in inflammatory cytokines, and insulin resistance. Daytime napping has been promoted as a countermeasure to sleep loss. To assess the effects of a 2-h midafternoon nap following a night of sleep loss on postnap sleepiness, performance, cortisol, and IL-6, 41 young healthy individuals (20 men, 21 women) participated in a 7-day sleep deprivation experiment (4 consecutive nights followed by a night of sleep loss and 2 recovery nights). One-half of the subjects were randomly assigned to take a midafternoon nap (1400-1600) the day following the night of total sleep loss. Serial 24-h blood sampling, multiple sleep latency test (MSLT), subjective levels of sleepiness, and psychomotor vigilance task (PVT) were completed on the fourth (predeprivation) and sixth days (postdeprivation). During the nap, subjects had a significant drop in cortisol and IL-6 levels (P < 0.05). After the nap they experienced significantly less sleepiness (MSLT and subjective, P < 0.05) and a smaller improvement on the PVT (P < 0.1). At that time, they had a significant transient increase in their cortisol levels (P < 0.05). In contrast, the levels of IL-6 tended to remain decreased for approximately 8 h (P = 0.1). We conclude that a 2-h midafternoon nap improves alertness, and to a lesser degree performance, and reverses the effects of one night of sleep loss on cortisol and IL-6. The redistribution of cortisol secretion and the prolonged suppression of IL-6 secretion are beneficial, as they improve alertness and performance.

Adolescent↗

PubMed2005

Myocardial border detection by branch-and-bound dynamic programming in magnetic resonance images.

Dynamic programming (DP) is a mathematical technique for making optimal decisions on the sequencing of interrelated problems. It has been used widely to detect borders in magnetic resonance images (MRI). MRI is noninvasive and generates clear images; however, it is impractical for manual measurement of the huge number of images generated by dynamic organs such as those of the cardiovascular system. A fast and effective algorithm is essential for on-line implementation of MRI-based computer aided measurement and diagnosis. In this paper, a branch-and-bound dynamic programming technique is applied to detect the endocardial borders of the left ventricular. The proposed branch-and-bound method drastically reduces the computational time required in conventional exhaustive search methods. Statistical tests are conducted to verify the CPU time performance of the branch-and-bound technique in comparison to the conventional exhaustive search method.

Computers↗

PubMed2005

Stability of the insecticide cypermethrin during tomato processing and implications for endocrine activity.

The thermal and pH stabilities of cypermethrin during food processing were investigated using tomato as a model food system and high-performance liquid chromatography as the analytical method. Cypermethrin was thermally unstable in aqueous conditions, where the hydrolysis of the pesticide was accelerated by heat. The mean proportion remaining after heating cypermethrin in water for 10 min was 66%, falling to 27% after 1 h. Similarly, thermal processing of canned tomatoes caused cypermethrin to degrade, with remaining levels in the final product ranging from 30 to 60% of the original. Cypermethrin was unstable at extreme pHs, with acid hydrolysis occurring faster than alkaline hydrolysis in phosphate buffers. The acidity of tomato paste (pH 4.3) caused cypermethrin levels to decrease by 30% within 12 days at 5 degrees C. The studies indicate that cypermethrin residues are likely to degrade by hydrolysis during food processing, thus reducing the exposure of consumers to cypermethrin. 3-Phenoxybenzaldehyde, a hydrolysis breakdown product of cypermethrin, was detected in the tomato paste and from the heating of cypermethrin in water at 100 degrees C. There is concern that the risk of breakdown products in terms of endocrine activity is unknown since in vitro studies reported that cypermethrin breakdown products display endocrine activity.

Chromatography, High Pressure Liquid↗

PubMed2003

Detection of Burkholderia pseudomallei in rice fields with PCR-based technique.

Burkholderia pseudomallei Ara- in rice fields was detected using PCR-based techniques with 16S RNA and flagella gene primer sets. The sensitivity of these PCRs was at least 1 CFU/mL of B. pseudomallei Ara- preincubated into Ashdown's medium for 6 h. B. pseudomallei Ara- DNA from watery soil were more detectable than from dry soil. The distribution of this DNA was mainly found at a depth of 300-600 mm under crop-covered fields, but not detected in the location of soil close to the land surface. The results suggest that PCR based on 16S RNA and flagella gene primer sets can be applied to investigate the presence of B. pseudomallei Ara- in contaminated soil of rice fields.

Burkholderia pseudomallei↗

PubMed2002

Electrochemistry: building on bubbles in metal electrodeposition.

In the electrodeposition of metals, a widely used industrial technique, bubbles of gas generated near the cathode can adversely affect the quality of the metal coating. Here we use phase-contrast radiology with synchrotron radiation to witness directly and in real time the accumulation of zinc on hydrogen bubbles. This process explains the origin of the bubble-shaped defects that are common in electrodeposited coatings.

Journal Article↗

PubMed2001

An isoform of branched-chain aminotransferase is a novel co-repressor for thyroid hormone nuclear receptors.

The functions of thyroid hormone receptors (TRs) are regulated by a host of co-regulatory proteins. Tissue-specific expression of these co-regulators leads to distinct expression patterns and regulation of thyroid hormone (T3) target genes in tissues. Previously we have found that human colon carcinoma RKO cells exhibit strong T3-independent transcriptional activity. We therefore searched for co-regulatory proteins in RKO cells using a yeast two-hybrid system with the intact TRbeta1 as bait. One of the three positive clones, designated as P3, was identified to be an isoform of human mitochondria branched-chain aminotransferase (BCATm). P3 was a spliced variant of BCATm with an internal 12-amino acid deletion near the carboxyl-terminal region and was abundantly expressed in RKO cells. The expressed protein localized both to the mitochondria and the nucleus of transfected CV1 cells. P3 physically interacted with TRbeta1 in a T3-independent manner that led to the inhibition in binding of TRbeta1 to thyroid hormone-responsive element. P3 not only enhanced the repressor activity of the unliganded TR but also repressed the ligand-dependent activation of TR. This repression was reversed by treatment of cells with trichostatin A, suggesting that in addition to the inhibition of DNA binding, the repression activity of P3 on TR may also be mediated by histone deacetylase activity. Thus, unlike the currently known co-repressors, P3 is a novel ligand-independent co-repressor for TR.

Animals↗

PubMed2001

Bcl-2 induces cyclin D1 promoter activity in human breast epithelial cells independent of cell anchorage.

Cyclin D1 expression is co-regulated by growth factor and cell adhesion signaling. Cell adhesion to the extracellular matrix activates focal adhesion kinase (FAK), which is essential for cyclin D1 expression. Upon the loss of cell adhesion, cyclin D1 expression is downregulated, followed by apoptosis in normal epithelial cells. Since bcl-2 prevents apoptosis induced by the loss of cell adhesion, we hypothesized that bcl-2 induces survival signaling complementary to cell adhesion-mediated gene regulation. In the present study, we investigated the role of bcl-2 on FAK activity and cyclin D1 expression. We found that bcl-2 overexpression induces cyclin D1 expression in human breast epithelial cell line MCF10A independent of cell anchorage. Increased cyclin D1 expression in stable bcl-2 transfectants is not related to bcl-2-increased G1 duration, but results from cyclin D1 promoter activation. Transient transfection studies confirmed anchorage-independent bcl-2 induction of cyclin D1 promoter activity in human breast epithelial cell lines (MCF10A, BT549, and MCF-7). We provide evidence that bcl-2 induction of cyclin D1 expression involves constitutive activation of focal adhesion kinase, regardless of cell adhesion. The present study suggests a potential oncogenic activity for bcl-2 through cyclin D1 induction, and provides an insight into the distinct proliferation-independent pathway leading to increased cyclin D1 expression in breast cancer.

Breast↗

PubMed2001

Haplotype analysis of the myotonic dystrophy type 1 (DM1) locus in Taiwan: implications for low prevalence and founder mutations of Taiwanese myotonic dystrophy type 1.

Myotonic dystrophy type 1 (DM1) is an autosomal dominant neuromuscular disorder caused by a CTG trinucleotide expansion at the DM1 locus. In this study, we investigated the frequency distribution of various CTG repeats in normal alleles and haplotyped the normal and expanded DM1 locus in a group of Taiwanese people. In the 496 normal chromosomes examined, up to 18 alleles with different CTG lengths from 5 to 30 repeats were found and the frequency of (CTG)(>18) alleles was only 1.4% (7/496), predicting a low prevalence of DM1. In addition, there is no absolute association between (CTG)(5-19) alleles and Alu insertion/deletion polymorphism observed on normal chromosomes. All DM1 alleles examined, however, were found to be associated with the Alu insertion. Further detailed genetic analysis demonstrated that at least eight haplotypes, including a new haplotype (L), were present in the Taiwanese population and that all DM1 alleles were with the same haplotype (haplotype A) as that identified in Canadian and Japanese DM1 populations. These findings support the notion that the out-of-Africa DM1 alleles were originated by stepwise expansion from a pool of large-sized normal chromosomes with haplotype A.

Alleles↗

PubMed2001

Determination of the timing of fetal brain damage from hypoxemia-ischemia.

OBJECTIVE: This study analyzed the cases of 55 children with cerebral palsy to evaluate methods for determination of the time before birth at which antenatal hypoxemia-ischemia damaged the brain. STUDY DESIGN: In primate fetuses persistent fetal bradycardia develops close to the time that hypoxemia-ischemia damages basal ganglia structures in the brain. The same proved true in children in this study, so this time was thereafter used as a baseline to test the values of other proposed timers of hypoxemicischemic brain damage. RESULTS: Basal ganglia lesions predominated when bradycardia lasted <30 minutes before birth. As the bradycardia duration lengthened, white matter and eventually watershed brain lesions predominated. Lymphocytosis appeared 25 minutes after the bradycardia began, and thrombocytopenia appeared at 20 to 28 hours. The lymphocytosis disappeared 14 to 18 hours after it first appeared. CONCLUSIONS: Counting back from the time that lymphocytosis ended and thrombocytopenia began can sometimes identify the time when hypoxemia-ischemia damaged the fetal brain.

Basal Ganglia↗

PubMed2001

A measure of association between two sets of multivariate responses.

Let X and Y denote two distinct sets of multivariate responses, each of which can be a mix of continuous and ordinal data. Suppose that it is of interest to quantify the overall strength of association between X and Y. Our two approaches to this problem are to construct correlation coefficients similar to Kendall's tau in the bivariate case. The first approach uses the average concordance of each pair of individuals, where the average concordance is obtained across all possible pairings of variables between the two sets, as the kernel of the U-statistic. Then the overall correlation between the two sets of multivariate data is expressed in terms of the expected value of the kernel. The second approach estimates pairwise Kendall's taus between the two sets, then uses a summary measure to quantify the overall association. One option for the summary measure is to take the average of taus, and another option is to take the distance of taus. The two approaches yield the same results when the summary measure of the latter is the average. However, using the distance of taus can sometimes detect relationships not seen in the average. We illustrate the proposed methods using data from a national asthma clinical trial in which the first set of variables comprises 12 binary responses of skin allergen tests and the second set of variables comprises three continuous outcomes of pulmonary function and one clinical outcome.

Adrenergic beta-Agonists↗

PubMed2001

Determination of Enterococcus faecalis groESL full-length sequence and application for species identification.

Amplification of the partial Cpn60 (or GroEL) gene segment has been used for identification of many bacteria, including Enterococcus species. To obtain more sequence data from groESL genes of Enterococcus faecalis, the full-length sequence of the E. faecalis groESL genes containing groES (285 bp), spacer (57 bp), and groEL (1,626 bp) was determined. A database search of GenBank revealed that the deduced E. faecalis GroES and GroEL proteins show significant homology to the GroES and GroEL proteins of other bacteria. The GroEL (groEL) of E. faecalis had the highest identity with Streptococcus pneumoniae (81.8% amino acid sequence identity and 73.0% nucleotide sequence identity), followed by Lactococcus zeae, while GroES (groES) had 60.2% (64.6%) identity with Lactobacillus zeae and 58.5% (66.2%) identity with Lactococcus lactis, followed by 57.0% (65.5%) identity with Bacillus subtilis. Based on the groES sequence, an E. faecalis-specific PCR assay was developed, and this PCR assay was positive for all the E. faecalis strains tested. Dot blot hybridization using either groES or groEL as the probe distinguished E. faecalis clearly from other species, indicating that both genes can be used as suitable targets for E. faecalis identification. Moreover, broad-range PCR-restriction fragment length polymorphism of groESL was designed to differentiate eight commonly encountered Enterococcus species. The Enterococcus species of reference strains could be easily differentiated on the basis of restriction patterns produced by HaeIII and RsaI. The DNA-based assays developed in this study provide an alternative to currently used methods of identification for clinically important enterococcal species.

Bacterial Proteins↗

PubMed2001

Prevalence of sleep-disordered breathing in women: effects of gender.

The prevalence of sleep-disordered breathing has not been well studied in women, especially in terms of the effects of age, body mass index (BMI), and menopause. We evaluated this question using a two-phase random sample from the general population. In Phase I, 12,219 women and 4,364 men ranging in age from 20 to 100 yr were interviewed; and in Phase II, 1,000 women and 741 men of the Phase I subjects were selected for one night of sleep laboratory evaluation. The results of our study indicated that, for clinically defined sleep apnea (apnea/hypopnea index > or = 10 and daytime symptoms), men had a prevalence of 3.9% and women 1.2%, resulting in an overall ratio of sleep apnea for men to women of 3.3:1 (p = 0.0006). The prevalence of sleep apnea was quite low in premenopausal women (0.6%) as well as postmenopausal women with hormone replacement therapy (HRT) (0.5%). Further, in these women the presence of sleep apnea appeared to be associated exclusively with obesity (BMI > or = 32.3 kg/m2). Postmenopausal women without HRT had a prevalence of sleep apnea that was significantly higher than the prevalence in premenopausal women with HRT (2.7 versus 0.6%, p = 0.02) and was more similar to the prevalence in men (3.9%), although it remained significantly less when controlling for age and BMI (p = 0.001). These data combined indicate that menopause is a significant risk factor for sleep apnea in women and that hormone replacement appears to be associated with reduced risk.

Adult↗

PubMed2001

Surfactant protein gene A, B, and D marker alleles in chronic obstructive pulmonary disease of a Mexican population.

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation. It is most likely the result of complex interactions of environmental and genetic factors. Because pulmonary surfactant components play important roles in normal lung function, innate host defence, and inflammation in the lung, this study investigated the hypothesis that the surfactant protein genes are involved in certain cases of COPD. Genotype analysis of surfactant protein (SP)-A, SP-B, SP-B-linked microsatellite, and SP-D marker alleles was performed in patients with COPD (n=97) and smoker (n=82) or nonsmoker (n=99) controls. Univariate and multiple logistic regression analyses were performed. The regression analysis results between COPD and smokers revealed several COPD susceptibility alleles (AA62_A, B1580_C, D2S388_5), based on an odds ratio (OR >2.5). The predictive ability of this model for developing COPD is good (c=0.926). Allele-allele (B1580_C and D2S388_5) and allele-environment (i.e. smoking) interactions were detected. When smoker controls were compared to nonsmoker controls, marker D2S388 5 appeared to be smoking-independent (p=0.874), whereas marker alleles AA62_A (p=0.045) and B1580_5 (p=0.007) were smoking-dependent. Males were at higher risk (OR=6.05, p=0.001), and smoking (>50 packs x yr(-1)) increased risk (OR=5.38, p=0.007). Males and alleles of loci flanking SP-B were associated with more severe cases (forced expiratory volume in one second/forced vital capacity < or = 40%). The present results indicate that the surfactant protein alleles may be useful in chronic obstructive pulmonary disease by either predicting the disease in a subgroup and/or by identifying disease subgroups that may be used for therapeutic intervention. These observations should now be confirmed in a larger study, designed according to strict epidemiological criteria.

Aged↗

PubMed2001

Middle-aged men show higher sensitivity of sleep to the arousing effects of corticotropin-releasing hormone than young men: clinical implications.

The prevalence of insomnia associated with emotional stress increases markedly in middle-age. Both the top and end hormones of the hypothalamic-pituitary-adrenal axis, i.e. CRH and glucocorticoids, stimulate arousal/wakefulness and inhibit slow wave (deep) sleep in experimental animals and man. The objective of this study was to test the hypothesis that middle-age is characterized by increased sensitivity to the sleep-disturbing effects of the hypothalamic-pituitary-adrenal axis. We studied 12 healthy middle-aged (45.1 +/- 4.9) and 12 healthy young (22.7 +/- 2.8) men by monitoring their sleep by polysomnography for 4 consecutive nights, including in tandem 1 adaptation and 2 baseline nights and a night during which we administered equipotent doses of ovine CRH (1 microg/kg, iv bolus) 10 min after sleep onset. Analyses included comparisons within and between groups using multiple ANOVA and regression analysis. Although both middle-aged and young men responded to CRH with similar elevations of ACTH and cortisol, the former had significantly more wakefulness and suppression of slow wave sleep compared with baseline sleep; in contrast, the latter showed no change. Also, comparison of the change in sleep patterns from baseline to the CRH night in the young men to the respective change observed in middle-aged men showed that middle-age was associated with significantly higher wakefulness and significantly greater decrease in slow wave sleep than in young age. We conclude that middle-aged men show increased vulnerability of sleep to stress hormones, possibly resulting in impairments in the quality of sleep during periods of stress. We suggest that changes in sleep physiology associated with middle-age play a significant role in the marked increase of prevalence of insomnia in middle-age.

Adrenocorticotropic Hormone↗

PubMed2001

Chronic insomnia is associated with nyctohemeral activation of the hypothalamic-pituitary-adrenal axis: clinical implications.

Although insomnia is, by far, the most commonly encountered sleep disorder in medical practice, our knowledge in regard to its neurobiology and medical significance is limited. Activation of the hypothalamic-pituitary-adrenal axis leads to arousal and sleeplessness in animals and humans; however, there is a paucity of data regarding the activity of the hypothalamic-pituitary-adrenal axis in insomniacs. We hypothesized that chronic insomnia is associated with increased plasma levels of ACTH and cortisol. Eleven young insomniacs (6 men and 5 women) and 13 healthy controls (9 men and 4 women) without sleep disturbances, matched for age and body mass index, were monitored in the sleep laboratory for 4 consecutive nights, whereas serial 24-h plasma measures of ACTH and cortisol were obtained during the fourth day. Insomniacs, compared with controls, slept poorly (significantly higher sleep latency and wake during baseline nights). The 24-h ACTH and cortisol secretions were significantly higher in insomniacs, compared with normal controls (4.2 +/- 0.3 vs. 3.3 +/- 0.3 pM, P = 0.04; and 218.0 +/- 11.0 vs. 190.4 +/- 8.3 nM, P = 0.07). Within the 24-h period, the greatest elevations were observed in the evening and first half of the night. Also, insomniacs with a high degree of objective sleep disturbance (% sleep time < 70), compared with those with a low degree of sleep disturbance, secreted a higher amount of cortisol. Pulsatile analysis revealed a significantly higher number of peaks per 24 h in insomniacs than in controls (P < 0.05), whereas cosinor analysis showed no differences in the temporal pattern of ACTH or cortisol secretion between insomniacs and controls. We conclude that insomnia is associated with an overall increase of ACTH and cortisol secretion, which, however, retains a normal circadian pattern. These findings are consistent with a disorder of central nervous system hyperarousal rather than one of sleep loss, which is usually associated with no change or decrease in cortisol secretion or a circadian disturbance. Chronic activation of the hypothalamic-pituitary-adrenal axis in insomnia suggests that insomniacs are at risk not only for mental disorders, i.e. chronic anxiety and depression, but also for significant medical morbidity associated with such activation. The therapeutic goal in insomnia should be to decrease the overall level of physiologic and emotional arousal, and not just to improve the nighttime sleep.

Adrenocorticotropic Hormone↗

PubMed2001

Delineation of CTG repeats and clinical features in a Taiwanese myotonic dystrophy family.

Myotonic dystrophy (DM) is an inherited, autosomal dominant muscular disease which is primarily caused by a CTG trinucleotide expansion mutation on chromosome 19q13.3. The size of this trinucleotide repeat is related both to the age of onset and to the severity of the clinical manifestation. This disease is very rare in Taiwan, and clinical and genetic study on DM has not yet been documented in this area. Here, we present both clinical features and degrees of CTG expansion for a Taiwanese DM family. All of the DM patients examined in this family showed obvious clinical manifestations by age 30, which included facial and limb muscle weakness with atrophy, myotonia, and ptosis. In addition, individual DM members also exhibited variable phenotypes, which may reflect the complexity of the pathogenic mechanism. Because the collection of blood specimens was considered to be an invasive procedure, a genetic study on this DM family was performed using buccal cells. Our results confirmed that four members showing classic symptoms of DM had CTG repeat expansion in the DMI locus, and that one member with ptosis and minor muscle weakness in the right foot was a normal homozygote for CTG repeat. These data demonstrate that buccal cells can provide clear and reliable results, and thus, are suitable for a family study of DM.

Alleles↗

PubMed2000

Surfactant protein genetic marker alleles identify a subgroup of tuberculosis in a Mexican population.

Pulmonary surfactant and its components are essential for normal lung function and are involved in local host defense. Surfactant protein (SP)-A and SP-D bind to and modulate phagocytosis of Mycobacterium tuberculosis by macrophages. Frequency comparisons of SP marker alleles in tuberculosis patients and healthy control subjects (tuberculin-skin test positive or general population) were performed. Regression analyses of the tuberculosis and the tuberculin-skin test positive groups revealed, on the basis of odds ratios, tuberculosis susceptibility (DA11_C and GATA_3) and protective (AAGG_2) marker alleles. Similarly, between tuberculosis patients and general population control subjects, susceptibility 1A(3), 6A(4), and B1013_A and protective AAGG_1, and AAGG_7 marker alleles were observed. Moreover, interactions were seen between alleles 6A(2) and 1A(3) (P=.0064) and between 1A(3) and B1013_A (P=. 036). The findings indicate a possible involvement of SP alleles in tuberculosis pathogenesis.

Adult↗