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Biomedical subjects

H Chuang

Publications and source records attributed to H Chuang.

15 recordsLinked to original sources
PubMed2006

Regular tai chi chuan exercise enhances functional mobility and CD4CD25 regulatory T cells.

BACKGROUND: The duration and vigour of physical exercise are widely considered to be critical elements that may positively or negatively affect physical health and immune response. OBJECTIVES: To investigate the effect of a 12 week programme of regular tai chi chuan exercise (TCC) on functional mobility, beliefs about benefits of exercise on physical and psychological health, and immune regulation in middle aged volunteers. METHODS: This quasi-experimental research design involving one group with testing before and after the programme was conducted to measure the effect of 12 weeks of TCC exercise in 14 men and 23 women from the normal community. RESULTS: Regular TCC exercise had a highly significant positive effect on functional mobility (p = 0.001) and beliefs about the health benefits of exercise (p = 0.013) in the 37 participants. Total white blood cell and red blood cell count did not change significantly, but a highly significant (p<0.001) decrease in monocyte count occurred. A significant (p = 0.05) increase in the ratio of T helper to suppressor cells (CD4:CD8) was found, along with a significant (p = 0.015) increase in CD4CD25 regulatory T cells. Production of the regulatory T cell mediators transforming growth factor beta and interleukin 10 under specific antigen stimulation (varicella zoster virus) was also significantly increased after this exercise programme. CONCLUSIONS: A 12 week programme of regular TCC exercise enhances functional mobility, personal health expectations, and regulatory T cell function.

Attitude to Health↗
PubMed2004

Polymorphism of the immune-braking gene CTLA-4 (+49) involved in gender discrepancy of serum total IgE levels and allergic diseases.

BACKGROUND: A variety of genes are related to allergic disorders in different ethnic populations. The genetic basis for the gender discrepancy of allergic diseases remains to be determined. OBJECTIVE: This study was conducted to investigate whether IL-4 promoter (-590 C/T) and cytotoxic T lymphocyte antigen 4 (CTLA-4) (+49 A/G) polymorphisms were correlated with a gender discrepancy of total IgE levels and allergic diseases in a Chinese population. METHODS: A total of 1333 participants aged 19-49 years were enrolled in this study. Allergic diseases were recognized by the presence of asthma, rhinitis or atopic dermatitis in conjunction with detectable specific IgE in the blood. Polymorphisms of IL-4 promoter (-590) and CTLA-4 (+49) were determined by restriction fragment length polymorphism. RESULTS: Males or females with allergic diseases had higher total IgE levels than those without (P=0.000). Females with the A/A genotype in the CTLA-4 (+49) position had significantly higher total IgE levels than those with A/G, and those with the G/G genotype had the lowest IgE levels (154.9 vs. 107.1 vs. 79.8 KU/L; mean log values: 1.79 vs. 1.65 vs. 1.54, P< 0.001). However, males with different genotypes in the CTLA-4 (+49) position exhibited no difference in the total IgE levels. Females with allergic rhinitis had a significantly higher frequency of the A/A genotype in the CTLA-4 (+49) polymorphism than those without atopic diseases (P=0.016). In contrast, males with and without allergic disorders exhibited no significant difference in the CTLA-4 (+49) polymorphisms (P>0.05). The IL-4 promoter (-590) polymorphisms, however, had no correlation with the total IgE levels or allergic diseases in either females or males. CONCLUSION: In females only, the CTLA-4 (+49), but not the IL-4 promoter (-590), polymorphism was significantly associated with elevation of total IgE levels and allergic rhinitis. Here, we have, for the first time, demonstrated a gender-linked genetic relationship with allergic disease.

Adult↗
PubMed2001

Optical sensors for detection of bacteria. 1. General concepts and initial development.

The concept of using immobilized nucleic acid stains as detection chemistry to fabricate optical bacterial sensors is first demonstrated. SYTO 13 (a green fluorescent cell stain) is used as the molecular recognition element and fluorescent reporter in the sensor. The sensor responds to aqueous and aerosolized bacterial samples in 15 and 30 min, respectively. In addition, the sensor can discriminate a change in Pseudomonas aeruginosa (Pa) cell concentration of 1 order of magnitude or less and can detect down to 2.4 x 10(5) cells/mL of Pa cells. The utility of the sensor is demonstrated by monitoring the growth of a Pa cell culture over a period of 50 h.

Bacteria↗
PubMed2000

The anandamide transport inhibitor AM404 activates vanilloid receptors.

The possibility that the anandamide transport inhibitor N-(4-hydroxyphenyl)-5,8,11,14-eicosatetraenamide (AM404), structurally similar to the vanilloid receptor agonists anandamide and capsaicin, may also activate vanilloid receptors and cause vasodilation was examined. AM404 evoked concentration-dependent relaxations in segments of rat isolated hepatic artery contracted with phenylephrine. Relaxations were abolished in preparations pre-treated with capsaicin. The calcitonin-gene related peptide (CGRP) receptor antagonist CGRP-(8-37) also abolished relaxations. The vanilloid receptor antagonist capsazepine inhibited vasodilation by AM404 and blocked AM404-induced currents in patch-clamp experiments on Xenopus oocytes expressing the vanilloid subtype 1 receptor (VR1). In conclusion, AM404 activates native and cloned vanilloid receptors.

Animals↗
PubMed1999

Unsaturated long-chain N-acyl-vanillyl-amides (N-AVAMs): vanilloid receptor ligands that inhibit anandamide-facilitated transport and bind to CB1 cannabinoid receptors.

We investigated the effect of changing the length and degree of unsaturation of the fatty acyl chain of N-(3-methoxy-4-hydroxy)-benzyl-cis-9-octadecenoamide (olvanil), a ligand of vanilloid receptors, on its capability to: (i) inhibit anandamide-facilitated transport into cells and enzymatic hydrolysis, (ii) bind to CB1 and CB2 cannabinoid receptors, and (iii) activate the VR1 vanilloid receptor. Potent inhibition of [(14)C]anandamide accumulation into cells was achieved with C20:4 n-6, C18:3 n-6 and n-3, and C18:2 n-6 N-acyl-vanillyl-amides (N-AVAMs). The saturated analogues and Delta(9)-trans-olvanil were inactive. Activity in CB1 binding assays increased when increasing the number of cis-double bonds in a n-6 fatty acyl chain and, in saturated N-AVAMs, was not greatly sensitive to decreasing the chain length. The C20:4 n-6 analogue (arvanil) was a potent inhibitor of anandamide accumulation (IC(50) = 3.6 microM) and was 4-fold more potent than anandamide on CB1 receptors (Ki = 0.25-0.52 microM), whereas the C18:3 n-3 N-AVAM was more selective than arvanil for the uptake (IC(50) = 8.0 microM) vs CB1 receptors (Ki = 3.4 microM). None of the compounds efficiently inhibited [(14)C]anandamide hydrolysis or bound to CB2 receptors. All N-AVAMs activated the cation currents coupled to VR1 receptors overexpressed in Xenopus oocytes. In a simple, intact cell model of both vanilloid- and anandamide-like activity, i.e., the inhibition of human breast cancer cell (HBCC) proliferation, arvanil was shown to behave as a "hybrid" activator of cannabinoid and vanilloid receptors.

Amidohydrolases↗
PubMed1999

Vanilloid receptors on sensory nerves mediate the vasodilator action of anandamide.

The endogenous cannabinoid receptor agonist anandamide is a powerful vasodilator of isolated vascular preparations, but its mechanism of action is unclear. Here we show that the vasodilator response to anandamide in isolated arteries is capsaicin-sensitive and accompanied by release of calcitonin-gene-related peptide (CGRP). The selective CGRP-receptor antagonist 8-37 CGRP, but not the cannabinoid CB1 receptor blocker SR141716A, inhibited the vasodilator effect of anandamide. Other endogenous (2-arachidonylglycerol, palmitylethanolamide) and synthetic (HU 210, WIN 55,212-2, CP 55,940) CB1 and CB2 receptor agonists could not mimic the action of anandamide. The selective 'vanilloid receptor' antagonist capsazepine inhibited anandamide-induced vasodilation and release of CGRP. In patch-clamp experiments on cells expressing the cloned vanilloid receptor (VR1), anandamide induced a capsazepine-sensitive current in whole cells and isolated membrane patches. Our results indicate that anandamide induces vasodilation by activating vanilloid receptors on perivascular sensory nerves and causing release of CGRP. The vanilloid receptor may thus be another molecular target for endogenous anandamide, besides cannabinoid receptors, in the nervous and cardiovascular systems.

Animals↗
PubMed1997

Regulation of IRK3 inward rectifier K+ channel by m1 acetylcholine receptor and intracellular magnesium.

Inward rectifier K+ channels control the cell's membrane potential and neuronal excitability. We report that the IRK3 but not the IRK1 inward rectifier K+ channel activity is inhibited by m1 muscarinic acetylcholine receptor. This m1 modulation cannot be accounted for by protein kinase C, Ca2+, or channel phosphorylation, but can be mimicked by Mg2+. Based on quantitative analyses of IRK3 and two different IRK1 mutant channels bestowed with sensitivity to m1 modulation, we suggest that the resting Mg2+ level causes chronic inhibition of IRK3 channels, and m1 receptor stimulation may lead to an increase of cytoplasmic Mg2+ concentration and further channel inhibition, due to the ability of Mg2+ to lead these channels into a prolonged inactivated state.

Amino Acid Sequence↗
PubMed1997

Scanning mutagenesis of the putative transmembrane segments of Kir2.1, an inward rectifier potassium channel.

Structural models of inward rectifier K+ channels incorporate four identical or homologous subunits, each of which has two hydrophobic segments (M1 and M2) which are predicted to span the membrane as alpha helices. Since hydrophobic interactions between proteins and membrane lipids are thought to be generally of a nonspecific nature, we attempted to identify lipid-contacting residues in Kir2.1 as those which tolerate mutation to tryptophan, which has a large hydrophobic side chain. Tolerated mutations were defined as those which produced measurable inwardly rectifying currents in Xenopus oocytes. To distinguish between water-accessible positions and positions adjacent to membrane lipids or within the protein interior we also mutated residues in M1 and M2 individually to aspartate, since an amino acid with a charged side chain should not be tolerated at lipid-facing or interior positions, due to the energy cost of burying a charge in a hydrophobic environment. Surprisingly, 17 out of 20 and 17 out of 22 non-tryptophan residues in M1 and M2, respectively, tolerated being mutated to tryptophan. Moreover, aspartate was tolerated at 15 out of 22 and 15 out of 21 non-aspartate M1 and M2 positions respectively. Periodicity in the pattern of tolerated vs. nontolerated mutations consistent with alpha helices or beta strands did not emerge convincingly from these data. We consider the possibility that parts of M1 and M2 may be in contact with water.

Alanine↗
PubMed1997

Electrospray mass spectrometry of testosterone esters: potential for use in doping control.

The study described involves an attempt to identify 17 beta-fatty acid esters of testosterone in blood plasma following administration of such agents. These drugs are therapeutic but are increasingly misused by athletes in an attempt to improve sports performance. The mass spectral properties of testosterone esters under electrospray ionization are described. These esters (testosterone acetate, propionate, isocaproate, benzoate, enanthate, cypionate, phenylpropionate, decanoate, and undecanoate) essentially give only a protonated molecular ion (MH+) under "optimum sensitivity" mass spectrometric conditions but could be induced to fragment in the source or collision cell of a triple quadrupole mass spectrometer. The underivatized steroid esters were analyzed by direct infusion because development of solvent systems compatible with high-performance liquid chromatography (HPLC) was not achieved for these nonpolar compounds. HPLC/MS (mass spectrometry) was possible when the steroids were converted to polar, water soluble, Girard hydrazones, and almost all were separated by microbore C4 HPLC using a water, acetonitrile, TFA gradient. The mass spectra under optimal ionization conditions essentially comprised only a molecular ion (M+), but source fragmentation gave major ions at M - 59 and M - 87 for all compounds. The molecular ion and these fragment ions were monitored in a selected-ion-recording (SIR) method developed for detecting the steroids in plasma. Using this methodology, testosterone enanthate and undecanoate could be detected after intramuscular injection or oral administration of the drugs. Further development of the technique could form the basis of a protocol for confirming the misuse of testosterone in sport, especially if sensitivity could be improved.

Chromatography, High Pressure Liquid↗
PubMed1997

Characterizing quality of life among patients with chronic mental illness: a critical examination of the self-report methodology.

OBJECTIVE: The purposes of the study were 1) to characterize the quality of life of three patient groups with chronic mental illness, 2) to evaluate differences in reported life quality among the three groups, and 3) to evaluate the validity of a self-report methodology by comparing these results with several objective indicators of life quality. METHOD: The study group consisted of chronically mentally ill patients with schizophrenia (N = 69), bipolar disorder (N = 37), or major depression (N = 35). Subjects were administered the Quality of Life Index, and comparisons of both objective and self-report life quality indices were made among the three groups. Quality of life ratings of these subjects were also compared with those of patients with a chronic physical illness. RESULTS: The two groups with mood disorders reported significantly lower scores on the Quality of Life Index than the patients with schizophrenia. Moreover, the scores on the Quality of Life Index for patients with schizophrenia were very similar to those of the comparison group of physically ill patients. The opposite trend emerged when groups were compared with respect to objective indicators of life quality. Schizophrenic patients experienced more objectively aversive life circumstances than either of the affectively disturbed groups. CONCLUSIONS: The validity of self-report measures of life satisfaction is questioned, particularly for use with affectively disturbed populations, since scores may be influenced by affective bias, poor insight, and recent life events.

Adult↗
PubMed1996

HIV disease.

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Canada↗
PubMed1992

Preparation and characterization of diaspirin cross-linked hemoglobin solutions for preclinical studies.

During 1990 and 1991 the capability for repetitive, consecutive production of DCLHb solution to meet a rigorous and complete set of product criteria was demonstrated. In addition, through periodic monitoring of product stored under controlled conditions, the stability of all lots of DCLHb solution during frozen storage was demonstrated for more than a year. In this way, assurance was provided that the DCLHb solution used in preclinical testing met all product criteria throughout the biological testing period.

Aspirin↗