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Biomedical subjects

Yan Yang

Publications and source records attributed to Yan Yang.

At least 37 records · Page 2Linked to original sources
PubMed2006

Thyroid status influence on adiponectin, acylation stimulating protein (ASP) and complement C3 in hyperthyroid and hypothyroid subjects.

BACKGROUND: Thyroid abnormalities (hyperthyroid and hypothyroid) are accompanied by changes in intermediary metabolism including alterations in body weight, insulin resistance and lipid profile. The aims of this study were to examine plasma ASP, its precursor C3 and adiponectin in hyperthyroid and hypothyroid subjects as compared to controls. METHODS: A total of 99 subjects were recruited from endocrinology/out-patient clinics: 46 hyperthyroid subjects, 23 hypothyroid subjects and 30 control subjects. Subjects were evaluated for FT4, FT3, TSH, glucose, insulin, complete lipid profile and the adipokines: adiponectin, acylation stimulating protein (ASP) and complement C3. RESULTS: Hyperthyroidism was associated with a 95% increase in adiponectin (p = 0.0002), a 47% decrease in C3 (p < 0.0001), no change in ASP and increased ASP/C3 ratio (p = 0.0012). Hypothyroidism was associated with a 31% increase in ASP (p = 0.008). Adiponectin and C3 correlated with FT3 (r = 0.383, p = 0.004 and r = -0.277, p = 0.007, respectively) and FT4 (r = 0.464, p = 0.003 and r = -0.225, p = 0.03, respectively). ASP correlated with TSH (r = 0.202, p = 0.04). Adiponectin did not correlate with either ASP or C3, only ASP and C3 correlated (r = -0.197, p = 0.05). Adiponectin was negatively correlated with BMI, total cholesterol and plasma triglyceride, while C3 was positively correlated with BMI and total cholesterol. Surprisingly, adiponectin was positively correlated with insulin (r = 0.293, p = 0.02) and HOMA-IR (r = 0.373, p = 0.003) while C3 was negatively correlated with glucose (r = -0.242, p = 0.022, insulin (r = -0.184, p = 0.05) and HOMA-IR. CONCLUSION: These changes suggest that thyroid disease may be accompanied by changes in adipokines, which may contribute to the phenotype expressed.

Journal Article↗
PubMed2006

Severe epilepsy resulting from genetic interaction between Scn2a and Kcnq2.

A mutation in the voltage-gated sodium-channel Scn2a results in moderate epilepsy in transgenic Scn2a(Q54) mice maintained on a C57BL/6J strain background. The onset of progressive epilepsy begins in adults with short-duration partial seizures that originate in the hippocampus. The underlying abnormality is an increase in persistent sodium current in hippocampal neurons. The voltage-gated potassium channel Kcnq2 is responsible for generating M current (I(KM)) that is thought to control excitability and limit repetitive firing of hippocampal neurons. To determine whether impaired M current would exacerbate the seizure phenotype of Scn2a(Q54) mice, we carried out genetic crosses with two mutant alleles of Kcnq2. Szt1 mice carry a spontaneous deletion that removes the C-terminal domain of Kcnq2. A novel Kcnq2 missense mutation V182M was identified by screening the offspring of ENU-treated males for reduced threshold to electrically evoked minimal clonic seizures. Double mutant mice carrying the Scn2a(Q54) transgene together with either of the Kcnq2 mutations exhibited severe epilepsy with early onset, generalized tonic-clonic seizures and juvenile lethality by 3 weeks of age. This dramatic exacerbation of the sodium-channel mutant phenotype indicates that M current plays a critical role in preventing seizure initiation and spreading in this animal model. The genetic interaction between Scn2a and Kcnq2 demonstrates that combinations of mild alleles of monogenic epilepsy genes can result in severe disease and provides a model for complex inheritance of human epilepsy. The data suggest that interaction between these genes might contribute to the variable expressivity observed in human families with sodium-channel mutations. In a screen of 23 SMEI patients with missense mutations of SCN1A, no second-site mutations in KCNQ2 were identified.

Amino Acid Sequence↗
PubMed2006

Structural elucidation of a novel fucogalactan that contains 3-O-methyl rhamnose isolated from the fruiting bodies of the fungus, Hericium erinaceus.

A new heteropolysaccharide, HEPF3, was isolated from the fruiting bodies of Hericium erinaceus. HEPF3 has a molecular weight of 1.9 x 10(4) Da and is composed of fucose and galactose in a ratio of 1:4.12. Compositional analysis, methylation analysis, together with 1H and 13C NMR spectroscopy established that HEPF3 consists of a branched pentasaccharide repeating unit with the following structure: [structure: see text]. HEPF3 also contains a minor proportion of 3-O-methylrhamnose that is thought to terminate the polymer main chain.

Basidiomycota↗
PubMed2006

Ectopic cell cycle events link human Alzheimer's disease and amyloid precursor protein transgenic mouse models.

Nerve cells that re-enter a cell cycle will die rather than divide, a fact that likely underlies the neurodegeneration in Alzheimer's disease (AD). Several mouse models of familial AD have been created, and although many display amyloid plaques in their brains, none captures the extensive pattern of nerve cell death found in the human disease. Using both immunocytochemistry and fluorescent in situ hybridization, we show that neurons in three different mouse models reproduce the ectopic cell cycling found in human AD. The temporal and spatial appearance of the cell cycle events in the mouse closely mimics the human disease progression. The cell-cycle events are evident 6 months before the first amyloid deposits and significantly precede the appearance of the first CD45+ microglia. These data suggest that the ectopic initiation of cell-cycle processes in neurons is an early sign of neuronal distress in both human and mouse AD. The close phenotypic correspondence indicates a previously unsuspected level of fidelity of the mouse model to the human disease. Finally, the relative timing suggests that neither the activated microglia nor the amyloid plaques themselves are necessary to initiate the pathogenic events in AD.

Alzheimer Disease↗
PubMed2006

Differential modulation of thalamic neurons by optokinetic nuclei in the pigeon.

The visual system in the pigeon is composed of the tectofugal, thalamofugal and accessory optic pathways. Though their anatomy and physiology have been extensively studied, the functional interactions between these pathways are largely unknown. The present study shows by using multiple electrophysiological techniques that firing activity in the nucleus opticus principalis thalami (OPT) of the thalamofugal pathway is differentially modulated by the pretectal nucleus lentiformis mesencephali (nLM) and the nucleus of the basal optic root (nBOR) of the accessory optic system, two optokinetic nuclei responsible for generating eye movements to stabilize the image on the retina. Reversible inactivation, electrical stimulation, microiontophoresis and receptive field mapping experiments all consistently indicate that the nBOR-OPT pathway is inhibitory and mediated by GABA as a transmitter and its GABAA receptors, whereas the nLM-OPT pathway is excitatory and mediated by glutamate as a transmitter and its NMDA receptors. They also differentially modulate the size and/or responsiveness of receptive fields in OPT cells as well. Numerous electrode tip sites were histologically confirmed in the neural structures under study. The results suggest that these optokinetic nuclei may dually modulate the transfer of visual information from the retina to the telencephalon at the thalamic level during eye movements.

Acetylcholine↗
PubMed2006

Three distinct profiles of serum complement C4 proteins in pediatric systemic lupus erythematosus (SLE) patients: tight associations of complement C4 and C3 protein levels in SLE but not in healthy subjects.

The serial changes of serum complement proteins C4 and C3 in SLE were characterized in 33 pediatric SLE patients with defined C4 genotypes. Three distinct groups of C4 protein profiles were observed. The first group was characterized by persistently low C4 levels (<10 mg/dL) throughout the course of the study. Patients with this profile had mild disease manifestations and low to medium copy numbers of C4 genes. The second group featured periodic fluctuations of serum C4 protein concentrations above and below 10 mg/dL, paralleled with ups and downs of SLE disease activities. Most patients with the second profile had unequal copy numbers of C4A and C4B genes and relatively severe disease. The third group had normal serum C4 levels (>15 mg/dL) most of the time and occasionally low C4 and C3 levels that were mostly coincident with disease flares prior to effective medical treatment. Most patients in this group

Adolescent↗
PubMed2006

Threshold estimation of ultrasound-induced lung hemorrhage in adult rabbits and comparison of thresholds in mice, rats, rabbits and pigs.

The objective of this study was to assess the threshold and superthreshold behavior of ultrasound (US)-induced lung hemorrhage in adult rabbits to gain greater understanding about species dependency. A total of 99 76 +/- 7.6-d-old 2.4 +/- 0.14-kg New Zealand White rabbits were used. Exposure conditions were 5.6-MHz, 10-s exposure duration, 1-kHz PRF and 1.1-micros pulse duration. The in situ (at the pleural surface) peak rarefactional pressure, p(r(in situ)), ranged between 1.5 and 8.4 MPa, with nine acoustic US exposure groups plus a sham exposure group. Rabbits were assigned randomly to the 10 groups, each with 10 rabbits, except for one group that had nine rabbits. Rabbits were exposed bilaterally with the order of exposure (left then right lung, or right then left lung) and acoustic pressure both randomized. Individuals involved in animal handling, exposure and lesion scoring were blinded to the exposure condition. Probit regression analysis was used to examine the dependence of the lesion occurrence on in situ peak rarefactional pressure and order of exposure (first vs. second). Likewise, lesion depth and lesion root surface area were analyzed using Gaussian tobit regression analysis. Neither probability of a lesion nor lesion size measurements was found to be statistically dependent on the order of exposure after the effect of p(r(in situ)) was considered. Also, a significant correlation was not detected between the two exposed lung sides on the same rabbit in either lesion occurrence or size measures. The p(r(in situ)) threshold estimates (in MPa) were similar to each other across occurrence (3.54 +/- 0.78), depth (3.36 +/- 0.73) and surface area (3.43 +/- 0.77) of lesions. Using the same experimental techniques and statistical approach, great consistency of thresholds was demonstrated across three species (mouse, rat and rabbit). Further, there were no differences in the biologic mechanism of injury induced by US and US-induced lesions were similar in morphology in all species and age groups studied. The extent of US-induced lung damage and the ability of the lung to heal led to the conclusion that, although US can produce lung damage at clinical levels, the degree of damage does not appear to be a significant medical problem.

Animals↗
PubMed2006

Synthesis of a precursor dipeptide of RGDS (Arg-Gly-Asp-Ser) catalysed by the industrial protease alcalase.

Synthesis of Bz-Arg-Gly-NH(2) (N-benzoylargininylglycinamide) [a precursor dipeptide of RGDS (Arg-Gly-Asp-Ser)] catalysed by protease in water/organic co-solvent systems was studied. Starting substrates were N-benzoyl-L-arginine ethyl ester hydrochloride (acyl donor) and glycinamide (nucleophile). Acetonitrile was selected as the organic solvent. Alcalase, an industrial alkaline protease, was applied to the synthesis of the target dipeptide. The conditions of the synthesis reaction were optimized by examining the effects of several factors, including water content, temperature, pH, molar ratio of the substrates and reaction time, on the yield of Bz-Arg-Gly-NH(2). The optimum conditions were established to be pH 10.0, 45 degrees C, in acetonitrile/0.1 M Na(2)CO(3)/NaHCO(3) buffer system (90:10, v/v) for 1 h with a dipeptide yield of 82.9%.

Catalysis↗
PubMed2006

Alcalase-catalyzed, kinetically controlled synthesis of a precursor dipeptide of RGDS in organic solvents.

The protease-catalyzed, kinetically controlled synthesis of a precursor dipeptide of RGDS, Z-Asp-Ser-NH2 in organic solvents was studied. Alcalase, an industrial alkaline protease, was used to catalyze the synthesis of the target dipeptide in water-organic cosolvents systems with Z-Asp-OMe as the acyl donor and Ser-NH2 as the nucleophile. Acetonitrile was selected as the organic solvent from acetonitrile, ethanol, methanol, DMF, DMSO, ethyl acetate, 2-methyl-2-propanol, and chloroform tested under the experimental conditions. The conditions of the synthesis reaction were optimized by examining the effects of several factors, including water content, temperature, pH, and reaction time on the Z-Asp-Ser-NH2 yields. The optimum conditions are pH 10.0, 35 degrees C, in acetonitrile/Na2CO3-NaHCO3 buffer system (85:15, v/v), 6 h, with a dipeptide yield of 75.5%.

Acetonitriles↗
PubMed2006

New synthetic route for RGD tripeptide.

A new route was employed to synthesize RGD. First, Gly-Asp dipeptide was synthesized by a novel chemical method in two steps, including chloroacetylation of L-aspartic acid and ammonolysis of chloroacetyl L-aspartic acid. Second, Nalpha-Z- L-Arginine was reacted with Gly-Asp to synthesize RGD by the N-carboxyanhydride method. Less protected amino acids were used in this synthesis. This method possessed advantages of low cost, simplicity, and rapidity with a reasonable yield of 62% calculated from arginine. In addition, compared with the above method, a conventional solid phase method was also used to synthesize RGD, the yield was 75% calculated from the first amino acid anchored to resin.

Chromatography, High Pressure Liquid↗
PubMed2006

[Expression of interferon alpha family gene of Chinese marmot in eukaryotic and prokaryotic cells].

OBJECTIVE: To investigate the function of interferon alpha (IFNalpha) in a Chinese marmot model of hepatitis B, we expressed the Chinese marmot (Marmota himalayana) IFNalpha family gene (IFNA) in eukaryotic cells and prokaryotic cells. METHODS: Eukaryotic and prokaryotic expression plasmids harboring Chinese marmot interferon alpha gene with different genotypes were generated using molecular cloning technology. We detected the biological activity of all expression products by viral protection assay, and analyzed their differences and species restriction of the biological activity. RESULTS: The Chinese marmot functional genotype IFNalpha was expressed in the baby hamster kidney (BHK) cell line, and these products protected WH12/6 cells challenged by encephalomyocarditis virus (EMCV). The Chinese marmot IFN-alpha5 also expressed in E. Coli induced by IPTG, and purified fusion protein had antiviral biological activity. The biologic activity displayed differences among different subtype IFNalpha, and it had strict species restriction. CONCLUSION: The IFNalpha family gene of the Chinese marmot can be expressed in both eukaryotic and prokaryotic cells, and the expression products show antiviral activity in a protection assay. This study provides, for the first time, evidence that IFNalpha from the Chinese marmot has an antiviral function in vitro and can be used to improve the efficacy of current therapies for HBV infection in our Chinese marmot model.

Animals↗
PubMed2006

[Evaluation on quitting intervention in health professionals of six cities].

OBJECTIVE: To evaluate the impact of quitting intervention in health professionals of six cities, developing smoking cessation models in China. METHODS: All community directors and health professionals in Seven communities were selected in six cities of Beijing, Shanghai, Tianjin, Changsha, Shenzhen and Puyang were surveyed for smoking cessation using cross-sectional study. RESULTS: There were 25 hospitals that kept on providing smoking cessation service after the intervention. The percent of the awareness about "the harm of smoking is public health problem" has improved 12.8%. The percent of getting some smoking cessation methods and actively providing smoking cessation have improved 9.2% and 7.3% respectively. CONCLUSION: Training the health professionals can not only increase their knowledge but also provide them smoking cessation service actively. It is a effective way to obtain methods and skills of quitting.

Attitude of Health Personnel↗
PubMed2006

[Relationship between depression symptoms and stress in occupational populations].

OBJECTIVE: To explore the relationship between the depression symptoms and occupational stress in occupational populations. METHODS: Depression symptoms were measured by using the center for epidemiological survey-depression scale. The occupational stress instrument were employed to investigate the stressors, personalities, social support, and coping strategies as well as the subject's age, length of service, sex, educational level and marriage status. Chi(2) test was used for analyzing the difference of depression. The multiple covariance analysis was used for testing the difference of stressors, personalities, social support, and coping strategies among the groups with different scores of depression. The variables obtained in the optional prediction equation were identified by multiple stepwise regression analysis. RESULTS: The incidence rate of definite depression symptoms was 40.2%. The total average score was 21.74 +/- 8.99. Henan province had the highest incidence rate of depression symptoms, 43.8%, Hebei 39.4%, and Beijing the lowest, 23.4%. The male workers had the higher incidence rate of depression symptoms, 43. 0% than female, 35.4% (P < 0.01). The older group had the lower incidence rates of depression symptoms, compared with the younger group (P < 0.01). The workers divorced or with the bereft spouse had the higher incidence rate of depression symptoms than the workers married and unmarried (P < 0.05). The workers with middle school education had the higher incidence rates of depression symptoms than those with master degree. Incidence rates in the most occupational groups were more than 30%. The significant difference was shown between the different jobs (P < 0.01). The difference of the adjusted means among three groups of different depression score were analyzed. The results showed the workers with definite depression symptoms had the higher scores than the other two groups in physical factors, role ambiguity, role conflict, job monotony, mental load, responsibility for persons, job future ambiguity, job hazards, type A behavior and work locus of control, and social support (P < 0.05, P < 0.01). The former had the lower scores than the other two groups in the scores of promotion, participation, autonomy, task identity, feedback, friendship opportunity, speed control, training adequacy, challenge, self-esteem, organizational commitment, and coping strategies. Fifteen variables entered the predictive equation of depression score explaining 33.1% of variance. CONCLUSION: There are serious mental health problems in the occupational population in our country. Stressors and personalities affect the mental health.

Adolescent↗
PubMed2006

[Human inward rectifying potassium current and Kir2.1 mRNA expression in myocytes isolated from patients with chronic atrial fibrillation].

OBJECTIVE: To compare the changes of both inward rectifying K(+) (Kir) current(I(k1)) density and mRNA expression level of Kir2.1, a major subfamily of Kir in chronic human atrial fibrillation (CAF) with those in normal sinus rhythm (NSR). METHODS: I(k1) density was measured with whole-cell patch clamp technique in single myocyte isolated by an enzymatic dissociation method from right atrial appendages in patients with CAF (n = 8) and those with NSR (n = 12). The mRNA expression levels of Kir2.1 was determined in right atrial appendages from CAF (n = 19) and NSR (n = 18) by semiquantitative reverse-transcription polymerase chain reaction (RT-PCR). RESULT: The average resting membrane potentials were similar between CAF and NSR (-78.95 mV +/- 4.67 mV and -70.22 mV +/- 11.08 mV, P>0.05). I(k1) density in single myocyte significantly increased at hyperpolarized potential level (-100 mV) in CAF compared to that in NSR (-9.59 pA/pF +/- 2.47 pA/pF vs. -5.58 pA/pF +/- 2.52 pA/pF, P<0.01). The mRNA level of Kir2.1 was also significantly higher in CAF than that of NSR (0.50+/-0.16 vs. 0.34+/-0.09, P<0.05). CONCLUSION: The data suggest that Kir2.1 up-regulation and I(k1) current increase might contribute to the electrical remodeling in CAF patients.

Atrial Fibrillation↗
PubMed2006

[Influence of different convergence angles on the retention of cast metal post and core].

Fifty-four simulated tooth roots made of polymethacrylate (PMMA) were divided into six groups according to the root canal convergence angles of 0 degrees, 3.93 degrees, 5.71 degrees, 7.48 degrees, 11.31 degrees, 14.71 degrees. Cast post and cores were manufactured and cemented with Zinc phosphate cement (ZP). The retention capacities of the posts were tested. The bonding strength of ZP at different convergence angles were tested with some casted wafers, and linear regression was made. So the effect of interlocking and the proportion could be calculated. With these results, we made some curvilinear regressions. The results showed that the retention of cast post declined and the bonding strength of ZP fell with the increase of convergence angles. There were significant differences in the bonding strength and retention among groups, P<0.05. The experiment indicates that the dentists should reduce the convergence angles of posts as much as possible to obtain greater retention.

Cementation↗
PubMed2006

[Research of L-type Ca2+ channel current in atrial myocytes of patients with chronic atrial fibrillation].

OBJECTIVE: To investigate the changes of L-type Ca(2+) channel current (I(Ca-L)) and its voltage-dependent activation and inactivation in atrial myocytes of patients with atrial fibrillation (AF). METHODS: The specimens of right atrial appendage were obtained from 18 patients with normal sinus rhythm (NSR) and 12 patients with chronic atrial fibrillation (CAF). Single myocytes were isolated by enzymatic dissociation with two-step method and the ionic currents were recorded using whole-cell patch clamp techniques to detect the changes of I(Ca-L) density and kinetic properties. RESULTS: (1) I(Ca-L) density was (-1.32 +/- 0.19) pA/pF in CAF group (n = 12) and (-4.58 +/- 0.39) pA/pF in NSR group (n = 21) at the test potential from -40 mV to 0 mV. I(Ca-L) density of CAF group was significantly reduced (P < 0.01), compared with the NSR group. (2) No significant differences were noted between the two groups in the voltage-dependent activation parameters (V(1/2), K) and inactivation parameters (V(1/2), K). CONCLUSIONS: I(Ca-L) density of CAF group was significantly decreased whereas it's voltage-dependent kinetic properties had no change. This phenomenon may be one of the mechanisms of atrial electrophysiological remodeling in chronic atrial fibrillation.

Atrial Fibrillation↗
PubMed2006

[Human inward rectifying potassium current in myocytes isolated from patients with rheumatic atrial fibrillation].

OBJECTIVE: To compare the changes of inward rectifying K(+) (Kir) current (I(K1)) density in atrial myocytes of patients with rheumatic atrial fibrillation (RAF) less or longer than 6 months. METHOD: I(K1) density was measured with whole-cell patch clamp technique in single myocyte isolated by an enzymatic dissociation method from right atrial appendages in patients with RAF less than 6 months (n = 18) and longer than 6 months (n = 18), RAF patients with normal sinus rhythm (NSR, n = 18) served as control. RESULTS: The average resting membrane potentials were similar between various groups. I(K1) density in single myocyte at -50 to -100 mV of patients with RAF longer than 6 months was significantly increased compared to that in patients with RAF less than 6 months and NSR patients. I(K1) density in single myocyte at hyperpolarized potential level (-100 mV) was also significantly increased in patients with RAF longer than 6 months (8.94 +/- 0.15) than that in patients with RAF less than 6 months (4.35 +/- 0.49) and NSR patients compared to that in NSR (4.05 +/- 0.96, P < 0.05 vs RAF longer than 6 months). CONCLUSION: The data suggest I(K1) current increase might contribute to the electrical remodeling in RAF patients.

Adult↗