Biomedical subjects

Y Jiang

Publications and source records attributed to Y Jiang.

At least 37 records · Page 2Linked to original sources

PubMed2006

Green tea extract thermogenesis-induced weight loss by epigallocatechin gallate inhibition of catechol-O-methyltransferase.

Epidemiological studies have shown that intake of tea catechins is associated with a lower risk of cardiovascular disease. The antioxidative activity of tea-derived catechins has been extensively studied. Reports have shown that green tea extract intake is associated with increased weight loss due to diet-induced thermogenesis, which is generally attributed to the catechin epigallocatechin gallate. That catechin-polyphenols are known to be capable of inhibiting catechol-O-methyltransferase (the enzyme that degrades norepinephrine) is a possible explanation for why the green tea extract is effective in stimulating thermogenesis by epigallocatechin gallate to augment and prolong sympathetic stimulation of thermogenesis. Knowledge about thermogenesis-induced weight loss produced by green tea's epigallocatechin gallate and its ability to inhibit catechol-O-methyltransferase is important for health benefits and for prolonging the action of norepinephrine in the synaptic cleft.

Adipose Tissue, Brown↗

PubMed2006

Involvement of potD in Streptococcus pneumoniae polyamine transport and pathogenesis.

Polyamines such as putrescine, spermidine, and cadaverine are small, polycationic molecules that are required for optimal growth in all cells. The intracellular concentrations of these molecules are maintained by de novo synthesis and transport pathways. The human pathogen Streptococcus pneumoniae possesses a putative polyamine transporter (pot) operon that consists of the four pot-specific genes potABCD. The studies presented here examined the involvement of potD in polyamine transport and in pneumococcal pathogenesis. A potD-deficient mutant was created in the mouse-virulent serotype 3 strain WU2 by insertion duplication mutagenesis. The growth of the WU2DeltapotD mutant was identical to that of the wild-type strain WU2 in vitro in rich media. However, WU2DeltapotD possessed severely delayed growth compared to wild-type WU2 in the presence of the polyamine biosynthesis inhibitors DFMO (alpha-dimethyl-fluoroornitithine) and MGBG [methylgloxal-bis (guanyl hydrazone)]. The mutant strain also showed a significant attenuation in virulence within murine models of systemic and pulmonary infection regardless of the inoculation route or location. These data suggest that potD is involved in pneumococcal polyamine transport and is important for pathogenesis within various infection models.

Animals↗

PubMed2006

Economic burden of smoking in China, 2000.

OBJECTIVE: To assess the health-related economic burden attributable to smoking in China for persons aged 35 and older. METHODS: A prevalence-based, disease-specific approach was used to estimate the smoking attributable direct costs, indirect morbidity costs, and costs of premature deaths caused by smoking-related diseases. The primary data source was the 1998 China National Health Services Survey, which contains the smoking status, medical utilisation, and expenditures for 216,101 individuals. RESULTS: The economic costs of smoking in 2000 amounted to $5.0 billion (measured in 2000, USD) in total and $25.43 per smoker (> or = age 35). The share of the economic costs was greater for men than women, and greater in rural areas than in urban areas. Of the $5.0 billion total costs, direct costs were $1.7 billion (34% of the total), indirect morbidity costs were $0.4 billion (8%), and indirect mortality costs were $2.9 billion (58%). The direct costs of smoking accounted for 3.1% of China's national health expenditures in 2000. CONCLUSION: The adverse health effects of smoking constitute a huge economic burden to the Chinese society. To reduce this burden in the future, effective tobacco control programmes and sustained efforts are needed to curb the tobacco epidemic and economic losses.

Adult↗

PubMed2006

A polysaccharopeptide complex and a condensed tannin with antioxidant activity from dried rose (Rosa rugosa) flowers.

In this study, the fraction (P) from an aqueous extract of dried rose (Rosa rugosa) flowers was obtained by ethanol precipitation. P was chromatographed on DEAE-cellulose. The components retained on DEAE-cellulose were eluted with a linear gradient of 0-2 M NaCl solution. Two fractions, eluted at concentrations of 0.5 M NaCl and 1 M NaCl, respectively, were obtained. These two components were designated as P1 and P2, respectively. P1 was further purified using gel filtration on Sephadex G-200. P(1) yielded two peaks, and the two components were designated as P(1-a) and P(1-b), respectively. P(1-a) was a polysaccharide-peptide complex, and P(1-b) exhibited chemical properties of a condensed tannin as revealed by FTIR and NMR assay of carbohydrate and protein contents and HPLC-ESI-MS. The molecular masses of P(1-a) and P(1-b) were 150 kDa and 8 kDa, respectively. Both P(1-a) and P(1-b) possessed antioxidant activity, with the activity of P(1-b) higher than that of P(1-a). This study demonstrated that different components from rose flowers exhibited antioxidant activity.

Animals↗

PubMed2006

Compounds from rose (Rosa rugosa) flowers with human immunodeficiency virus type 1 reverse transcriptase inhibitory activity.

The aqueous extracts and ethanol precipitates of aqueous extracts of 18 medicinal herbs traditionally used in China were screened for their ability to inhibit human immunodeficiency virus type-1 reverse transcriptase (HIV-1 RT) in-vitro. Among the samples screened at a concentration of 500 microg mL-1, dried rose (Rosa rugosa) flowers showed the strongest inhibition. The ethanol precipitate of the aqueous extract of R. rugosa was processed and two components (P1 and P2) were obtained after ion exchange chromatography on DEAE-cellulose. Then, P1-a (Mr 150 kDa) and P1-b (Mr 8 kDa) were isolated from P1 by gel filtration on Sephadex G-200. They inhibited the activity of HIV-1 RT with an IC50 of 158 nM and 148.16 microg mL-1 (18.5 microM), respectively. Further structural analyses revealed that P1-a was a polysaccharide-peptide complex, and P1-b was a polymer consisting of acteoside and acteoside derivatives identified by Fourier transform infrared spectroscopy, nuclear magnetic resonance, assays of carbohydrate and protein contents and high-performance liquid chromatography electrospray ionization mass spectrometry.

Chromatography, Gel↗

PubMed2006

Development of a recombinant fowlpox virus vector-based vaccine of H5N1 subtype avian influenza.

The genetic stability of the recombinant fowlpox virus (named rFPV-HA-NA) was confirmed by serial passage on chicken embryo fibroblast (CEF) cells. The immune efficacy, safety, the minimum immunising dose, the time of immunity induced and the immune duration of the vector-based vaccine was evaluated in specific-pathogen-free (SPF) chickens. The recombinant virus vaccine containing 100 plaque form units (PFU) could induce complete protection against challenge with H5N1 highly pathogenic avian influenza virus (HPAIV). The immune efficacy, protecting chickens from clinical signs and death after challenge, was obtained one week after the immunisation with this vaccine. Protective immunity could last for 40 weeks post-immunisation. So the recombinant fowlpox vaccine is a safe and highly effective gene engineering vaccine candidate, and will be used to prevent H5 subtype avian influenza in the future.

Animals↗

PubMed2005

Functional analysis of bovine herpesvirus 1 (BHV-1) genes expressed during latency.

Bovine herpes virus 1 (BHV-1) establishes latency in sensory neurons of trigeminal ganglia (TG), and germinal centers of pharyngeal tonsil. Periodically BHV-1 reactivates from latency, virus is shed, and consequently virus transmission occurs. Two transcripts, the latency related (LR) RNA and ORF-E, are abundantly expressed in TG of latently infected cattle. A LR mutant strain of BHV-1 was constructed that contains stop codons near the beginning of the LR-RNA. The LR mutant virus does not express two proteins encoded by the LR gene, or reactivate from latency suggesting that LR protein expression regulates the latency-reactivation cycle. Higher levels of apoptosis occur in TG of calves infected with the LR mutant versus wild type BHV-1 indicating that the anti-apoptotic properties of the LR gene regulate the latency-reactivation cycle. The LR gene also inhibits bICP0 expression and mammalian cell growth, but these functions do not require LR protein expression. In contrast, the ability of the LR gene to inhibit apoptosis appears to require LR protein expression. A small open reading frame (ORF-E) that is located within the LR promoter is expressed in the nucleus of neuroblastoma cells. We predict that the LR gene and ORF-E regulate the BHV-1 latency-reactivation cycle.

Animals↗

PubMed2005

Serum antibodies in epilepsy and seizure-associated disorders.

OBJECTIVE: To investigate whether autoantibodies to ion channels and other neural antigens are present in the sera of patients with epilepsy and seizure-related diseases. METHODS: Sera were obtained from 139 patients, including 26 with preexisting autoimmune disease, 46 in whom an autoimmune basis was suspected, and 67 with drug-resistant epilepsy. The sera were assayed for antibodies to voltage-gated potassium (VGKC) and calcium (VGCC) channels, glutamic acid decarboxylase (GAD), gangliosides, glutamate receptor type 3, cardiolipins, DNA, and nuclear antigens; the results were compared with results from a large cohort of healthy and disease controls. RESULTS: Increased titers of VGKC antibodies (>100 pM) were detected in 16 of 139 (11%) patients with seizures but only 1 control (0.5%). Eight VGKC-positive patients presented with an acute/subacute illness, and 5 of these had the highest VGKC antibodies; 3 patients improved spontaneously, another 5 patients responded well to immunomodulatory therapy. The other VGKC-positive patients had longer disease duration (>6 years) and intermediate levels of antibodies; immunotherapies have not been tested in this group. Very high levels of GAD antibodies (>1,000 U) were found in an additional 3 patients (2.1%) with long-standing drug-resistant epilepsy. CONCLUSIONS: The presence of autoantibodies to voltage-gated potassium channels and glutamic acid decarboxylase suggests that the immune system may contribute to certain forms of epilepsy or seizure-associated disorders. Further studies are needed to determine whether the antibodies are pathogenic.

Adolescent↗

PubMed2005

Characterization of CD8+ T lymphocytes in chronic HIV-1 subtype A infection in Rwandan women.

We examined CD8+ T lymphocyte characteristics in Rwandan women who have survived HIV-1 subtype A infection for 8-13 years without antiretroviral therapy. HIV-1 subtype A gag-specific IFN-gamma expressing CD8+ T lymphocytes were detectable in PBMC from 5 of 7 women and there was a strong positive association (r = 0.9262; p < 0.001) between these cells and plasma viral load. CD8+ T cells of these HIV-positive women produced more RANTES and MIP-1beta than cells from HIV-negative donors. However, extremely low levels of perforin (0.88 +/- 0.93%) were produced by CD8+ T lymphocytes from the infected women compared with HIV-negative controls (42.86 +/- 11.0%; p < 0.001). The percentages of CD8+ CD45RA+ perforin+ and CD8+ CD45RA+ CD27-lymphocytes were also much lower in the HIV-infected women compared with HIV-negative controls. Therefore, the inability of CD8+ T cells to control HIV may, in part, be dependent on insufficient generation of effectors from HIV-specific CD8+ T cells. Also, the lack of perforin in CD8+ T cells is linked with persistent CD27 expression, suggesting impaired maturation and impairment in cytolytic activity in chronic HIV-1 infection.

CD4-Positive T-Lymphocytes↗

PubMed2005

Survivin, Survivin-2B, and Survivin-deItaEx3 expression in medulloblastoma: biologic markers of tumour morphology and clinical outcome.

Survivin is an apoptotic inhibitor that is expressed at high levels in a variety of malignancies. Survivin has four known alternative splice forms (Survivin, Survivin-2B, Survivin-deltaEx3, and Survivin-3B), and the recent literature suggests that these splice variants have unique functions and subcellular localisation patterns. We evaluated 19 fresh-frozen paediatric medulloblastomas for the expression of three Survivin isoforms by quantitative PCR. Survivin was most highly expressed when compared with normal cerebellar tissue. We also investigated Survivin protein expression in 40 paraffin-embedded paediatric medulloblastoma tumours by immunohistochemistry. We found a statistically significant association between the percentage of Survivin-positive cells and histologic subtype, with the large-cell-anaplastic variant expressing Survivin at higher levels than the classic subtype. We also found a statistically significant relationship between the percent of Survivin-positive cells in the tumours and clinical outcome, with higher levels of Survivin correlating with a worse prognosis. In summary, our study demonstrates a role for Survivin as a marker of tumour morphology and clinical outcome in medulloblastoma. Survivin may be a promising future prognostic tool and potential biologic target in this malignancy.

Biomarkers, Tumor↗

PubMed2005

Single-beam and enhanced two-beam second-harmonic generation from silicon nanocrystals by use of spatially inhomogeneous femtosecond pulses.

Optical second-harmonic generation (SHG) is used as a noninvasive probe of the interfaces of Si nanocrystals (NCs) embedded uniformly in an SiO2 matrix. Measurements of the generated SH mode verify that the second-harmonic polarization has a nonlocal dipole form proportional to (E x Delta inverted) E that depends on inhomogeneities in the incident field E, as proposed in recent models based on a locally noncentrosymmetric dipolar response averaged over the spherical NC interfaces. A two-beam SHG geometry is found to enhance this polarization greatly compared to single-beam SHG, yielding strong signals useful for scanning, spectroscopy, and real-time monitoring. This configuration provides a general strategy for enhancing the second-order nonlinear response of centrosymmetric samples, as demonstrated here for both Si nanocomposites and their glass substrates.

Journal Article↗

PubMed2005

Differential effect of p75 neurotrophin receptor on expression of pro-apoptotic proteins c-jun, p38 and caspase-3 in dorsal root ganglion cells after axotomy in experimental diabetes.

We have hypothesized that p75 neurotrophin receptor (p75(NTR))-mediated activation of the pro-apoptotic proteins c-jun, p38 and caspase-3 underlies the neuronal cell loss in dorsal root ganglia (DRG) neurons after axotomy in normal mice, and that this activation is exaggerated in experimental diabetes. To test this hypothesized relationship, we compared the expression of pro-apoptotic proteins in fifth lumbar DRG (L5DRG) neurons of wildtype Balb/c (p75+/+) mice and p75(NTR) knockout (p75-/-) mice, assigned to either non-diabetic control groups or to diabetic (1 month) groups, all with a unilateral sciatic nerve crush produced 10 days before tissue preparation. The absolute number of L5DRG neurons expressing immunoreactivities (IR) for phosphorylated c-jun (P-c-jun-IR), phosphorylated p-38 (P-p38-IR) and cleaved caspase-3 (caspase-3-IR) were estimated in semi-thick sections using the optical fractionator. Nerve crush increased the numbers of P-c-jun-IR and caspase-3-IR neurons in all four groups. On the crush side, diabetes did not exaggerate the increase of P-c-jun-IR or caspase-3-IR neurons in p75+/+ mice, whereas in p75-/- mice diabetes reduced the increase of P-c-jun-IR neurons. Also, in p75-/- mice there was fewer caspase-3-IR cells on the intact and crushed side in comparison with p75+/+ mice independent of the presence of diabetes. This study demonstrates that (1) diabetes of 1 month's duration does not potentiate the expression of three pro-apoptotic markers p38, caspase-3 and P-c-jun neither in intact neurons nor after nerve crush, and that (2) p75(NTR) is required for activation of the pro-apoptosis signal caspase-3 after nerve crush in both diabetic and non-diabetic mice.

Animals↗

PubMed2005

Desferrioxamine induces leukemic cell differentiation potentially by hypoxia-inducible factor-1 alpha that augments transcriptional activity of CCAAT/enhancer-binding protein-alpha.

We reported recently that cobalt chloride-simulated hypoxia and mild hypoxia modified the differentiation of human acute myeloid leukemic (AML) cells, probably acting via a hypoxia-inducible factor-1 alpha (HIF-1 alpha)-dependent mechanism. In this study, we investigated the effect of desferrioxamine (DFO), an iron chelator with 'hypoxia-mimetic' activity, on the differentiation of AML cells. The results showed that DFO at nontoxic concentrations induced the differentiation of AML cell lines NB4 and U937, as assessed by morphological criteria and differentiation-associated antigens. DFO-induced differentiation parallel to the rapid accumulation of HIF-1 alpha protein in these two cell lines. Of importance, the transient transfection of HIF-1 alpha cDNA induced U937 cells to develop the differentiation-related alterations such as growth arrest and increased CD11b expression. Furthermore, the inducible expression of chromosome translocation t(8;21)-generated leukemogenic AML1-ETO fusion gene attenuated DFO-induced differentiation of U937 cells with the decrease of CCAAT/enhancer-binding protein alpha (C/EBP alpha), a critical factor for granulocytic differentiation. Using immunoprecipitation and luciferase reporter assay, HIF-1 alpha was also shown to interact physically with and to increase the transcriptional activity of C/EBP alpha. Taken together, these results provided novel evidence for a role of HIF-1 alpha in AML cell differentiation, and suggested that C/EBP alpha might be a downstream effector for HIF-1 alpha-mediated differentiation.

Acute Disease↗

PubMed2005

p53 gene mutations are uncommon but p53 is commonly expressed in anaplastic large-cell lymphoma.

Anaplastic large-cell lymphoma (ALCL), as defined in the World Health Organization, is a heterogeneous category in which a subset of cases is associated with the t(2;5)(p23;q35) or variant translocations resulting in overexpression of anaplastic lymphoma kinase (ALK). p53 has not been assessed in currently defined subsets of ALCL tumors. In this study, we assessed ALK+ and ALK- ALCL tumors for p53 gene alterations using PCR, single-strand conformation polymorphism and direct sequencing methods. We also immunohistochemically assessed ALCL tumors for p53 expression. Three of 36 (8%) ALCL tumors (1/14 ALK+, 2/22 ALK-) with adequate DNA showed p53 gene mutations. By contrast, p53 was overexpressed in 36 of 55 (65%) ALCL tumors (16 ALK+, 20 ALK-). p21, a target of p53, was expressed in 15 of 31 (48%) ALCL tumors including seven of 15 (47%) p53-positive tumors. p21 expression in a subset of ALCL suggests the presence of functional p53 protein. Apoptotic rate was significantly higher in p53-positive than p53-negative tumors (mean 2.78 vs 0.91%, P = 0.0003). We conclude that the p53 gene is rarely mutated in ALK+ and ALK- ALCL tumors. Nevertheless, wild-type p53 gene product is commonly overexpressed in ALCL and may be functional in a subset of these tumors.

Adult↗

PubMed2005

[13C] phenylalanine breath test and hepatic phenylalanine metabolism enzymes in cirrhotic rats.

BACKGROUND: Stable isotope 13C-labelled phenylalanine breath test has been applied to enable the quantitative evaluation of hepatic functional reserve, but the mechanism underlying the changes in function has not been resolved. This study evaluated the correlation between expression of the mRNA of key enzymes mediating phenylalanine metabolism and the metabolism of L-[1-13C] phenylalanine (13C-phe) assessed by the excretion of 13C-CO2 in the breath of rats with, and without, chronic hepatic injury induced by administration of carbon tetrachloride (CCl4). MATERIALS AND METHODS: Male Sprague-Dawley (SD) rats (n = 29) were given subcutaneous injections of CCl4 to induce chronic hepatic injury. L-[1-13C] phenylalanine breath tests (PheBT) were then applied to the rats to assess hepatic function. Expression of phenylalanine hydroxylase (PHH) and tyrosine transaminase (TYT) mRNA in liver was detected by real-time fluorescence quantification RT-PCR, using TaqMan as the probe. It was then determined whether the PheBT results correlated with PHH and/or TYT mRNA expression. In addition, immunohistochemical labelling was used to visualize PHH protein expression in the control and injured liver tissue. RESULTS: There were significant decreases in PheBT and PHH mRNA expression in the cirrhotic rats relative to the uninjured controls and these two measures of liver function were correlated. However, TYT mRNA expression was not changed by CCl4-induced liver injury. The immunohistochemical analysis revealed that PHH protein was expressed predominantly in the cytoplasm of liver cells. CONCLUSIONS: The results of the PheBT were consistent with the changes in PHH gene expression following liver injury. The present findings indicate that decreased expression of the rate-limiting enzyme PHH, but not of TYT, might underlie the functional deficits detected as decreased PheBT. The 13C excretion rate constant per mass liver (PheBT-k/LW) was the most sensitive index that could be used to evaluate the PHH mRNA expression in the liver.

Animals↗

PubMed2005

Using large eddy simulation to study particle motions in a room.

UNLABELLED: As people spend most of their time in an indoor environment, it is important to predict indoor pollutant level in order to assess health risks. As particles are an important pollutant indoors, it is of great interest to study the airflow pattern and particle dispersion in buildings. This study uses large eddy simulation (LES) to predict three-dimensional and transient turbulent flows and a Lagrangian model to compute particle trajectories in a room. The motion of three different types of solid particles in a decaying homogeneous isotropic turbulent airflow is calculated. By comparing the computed results with the experimental data from the literature, the computational method used in this investigation is found to be successful in predicting the airflow and particle trajectories in terms of the second-order statistics, such as the mean-square displacement and turbulent intensity. This Lagrangian model is then applied to the study of particles' dispersion in a ventilated cavity with a simplified geometry for two ventilation scenarios. It is shown that light particles follow the airflow in the room and many particles are exhausted, while heavier particles deposit to the floor or/and are exhausted. PRACTICAL IMPLICATIONS: The results of this paper can be used to study dispersion of infectious diseases in enclosed spaces in which virus or bacteria are often attached to particles and transported to different rooms in a building through ventilation systems. In most of studies, the virus or bacteria have been considered to be gaseous phase so there is no slip between virus/bacteria and air. The results in this paper show that heavier particles are submitted to gravity and are sensitive to the ventilation strategy.

Air Movements↗

PubMed2005

Polymorphisms of CD14 gene and TLR4 gene are not associated with ulcerative colitis in Chinese patients.

BACKGROUND AND AIMS: Toll-like receptor 4 and CD14 are the components of the lipopolysaccharide receptor complex. The aim of this study was to investigate the associations between polymorphisms TLR4 Asp299Gly and CD14 C-260T and Chinese patients with ulcerative colitis (UC). METHODS: Using a polymerase chain reaction based restriction fragment length polymorphism, the study genotyped polymorphisms TLR4 Asp299Gly and CD14 C-260T in 114 patients with UC and 160 healthy controls in the Chinese Han population. Moreover a comparison was made with 170 healthy Dutch white subjects. RESULTS: No TLR4 Asp299Gly mutation was detected in any patients or healthy controls in the Chinese Han population, which was similar to Japanese subjects, but the mutation occurred in 10% of the Dutch white subjects. There were no significant differences of CD14 genotypes between healthy controls and the patients with UC.

Asian People↗

PubMed2004

Automatic localization of epileptic zones using magnetoencephalography.

Conventional visual identification of epileptic spike is a challenging problem in the clinical application of magnetoencephalography (MEG). More importantly, the conventional method has problems of detecting other abnormalities such as high frequency oscillation in the human epileptic brain. The objective of this study was to develop a new approach using magnetic spectral analysis and spatial filtering. Twelve patients with seizure have been studied with a whole cortex MEG system. Fifteen epochs were recorded for each patient; each epoch was 120 seconds. Neuromagnetic spectrum was analyzed using a new method called accumulated spectrogram. Focal increases of spectral power were localized using synthetic aperture magnetometry (SAM). The MEG results were then compared with clinical findings. Focal increases of spectral power have been identified in all patients (12/12, 100%). The locations of the focal increases of spectral power were in agreement with dipole locations of spikes in 9 patients (9/12, 75%). A comparison between MEG results and clinical findings indicated that SAM revealed focal epileptic activities in two patients when dipole fitting failed. The results suggest that epileptic regions could be quantitatively identified and accurately localized using accumulated spectrogram and SAM. In comparison to visual identification of spike, the new approach is objective and sensitive, and provides the possibility of analyzing much wider frequency bands.

Adolescent↗