Search PubMed⌕ Search

Biomedical subjects

Xiang Gao

Publications and source records attributed to Xiang Gao.

At least 91 records · Page 5Linked to original sources

Plasma C-reactive protein and homocysteine concentrations are related to frequent fruit and vegetable intake in Hispanic and non-Hispanic white elders.

Elevated C-reactive protein (CRP) and plasma total homocysteine (Hcy) were recently identified as risk factors for cardiovascular disease. However, few studies have related fruit and vegetable consumption to these markers of inflammation and B vitamin deficiency, particularly in the Hispanic population. We examined the relation of fruit and vegetable intake with plasma CRP and Hcy concentrations in a cross-sectional study. Subjects were 445 Hispanic elders and 154 neighborhood-based non-Hispanic white elders living in Massachusetts. Diet was assessed with a FFQ designed for this population. There were significant inverse dose-response associations between fruit and vegetable intake and plasma CRP (P for trend = 0.010) and Hcy (P for trend = 0.033) concentrations, after adjustment for potential confounders. The prevalence of high plasma CRP (> 10 mg/L), and high Hcy (>10.4 micromol/L for women and >11.4 micromol/L for men), was significantly greater among subjects in the lowest quartile of fruit and vegetable consumption relative to those in the highest quartile, 17.9 vs. 9.1% and 58.7 vs. 44.4%, respectively. With each additional serving of fruit and vegetable intake, adjusted odd ratios for high plasma CRP and Hcy were 0.79 (95% CI: 0.65 to 0.97) and 0.83 (95% CI: 0.72 to 0.96), respectively. Greater frequency of fruit and vegetable intake was associated with significantly lower plasma CRP and Hcy concentrations. Because both of these metabolites are known risk factors for CVD, these findings contribute to the evidence that a higher intake of fruit and vegetables may reduce the risk of CVD.

Aged↗

SNAP-25 in hippocampal CA1 region is involved in memory consolidation.

As a synaptosomal protein, SNAP-25 plays a role in a number of neuronal functions including axonal growth, dendrite formation, fusion of synaptic vesicles with membrane and the expression of long-term potentiation (LTP) in the hippocampus. Using a learning/memory behavior screening, we identified SNAP-25 as one of the differentially expressed genes in the hippocampus upon behavioral training. The inhibition of SNAP-25 with intracerebroventricular antisense oligonucleotide caused a deficit in long- but not short-term memory for step-down inhibitory avoidance. Intra-CA1 infusion of the SNAP-25 antisense oligonucleotide impaired long-term contextual fear memory and spatial memory and interfered with the LTP of synaptic transmission in the CA1 region. The inhibitory effect on LTP was not mediated by a pre-synaptic mechanism because paired pulse facilitation of synaptic transmission was not affected after administration of the antisense oligonucleotide. Together, the results suggest that SNAP-25 in the CA1 region is involved in memory consolidation.

Animals↗

Applying a mapped pseudospectral time-domain method in simulating diffractive optical elements.

A new technique for the analysis of two-dimensional diffractive optical elements, by use of the pseudospectral time-domain (PSTD) method, is presented. In particular, the method uses a nonuniform (NU) grid and a mapping technique to obtain very accurate spatial derivatives in an efficient manner. To this end, we present the formulation of the PSTD method by using a NU grid and compare its application to the analysis with that of the finite-difference time-domain (FDTD) method. Using only a fraction of the memory and a fraction of the computation time used by FDTD, the mapped PSTD was able to obtain very close results to FDTD.

Journal Article↗

[Study on relationship between ambient PM10, PM2.5 pollution and daily mortality in a district in Shanghai].

OBJECTIVE: Explore the adverse impact of ambient particulate matter pollution on human health. METHODS: Generalized additive model (GAM) extended poisson regression was used to examined the exposure--response relationship between ambient PM10, PM2.5 pollution and daily mortality in a district in Shanghai. Regression analyses was used for analysis with adjustment for controlling time trends, weather, season, the day of the week. RESULTS: A 10 micrograms/m3 increase in PM10, and PM2.5 were associated with 0.53% (0.22%-0.85%), 0.85% (0.32%-1.39%) increase in total daily mortality respectively. CONCLUSION: Ambient particulate pollution has potential acute adverse health effects on human.

Air Pollutants↗

Removal of NOx from flue gas with radical oxidation combined with chemical scrubber.

In this paper, removal of NOx (namely DeNOx) from flue gas by radical injection combined with NaOH solution (26% by weight of NaOH in water) scrubbing was investigated. The experimental results showed that the steady streamer corona occurs through adjusting the flow rate of the oxygen fed into the nozzles electrode. The vapor in the oxygen has influence on the V-I characteristics of corona discharge. Both HNO2 and HNO3 come into being in the plasma reactor and the DeNOx efficiency in the plasma reactor is more than 60%. The overall DeNOx efficiency of the whole system reaches 81.7% when the NaOH solution scrubbing is collaborated.

Air Pollutants↗

Bone marrow stromal cell line co-transfected with IL-2 and IL-3 genes can accelerate restoration of T-cell immunity in allo-BMT mice.

BACKGROUND: After T-cell depleted allogeneic bone marrow transplantation, impaired immune reconstitution is a major cause of morbidity and mortality in the recipient. The purpose of this study was to observe the effects of the gene-engineered bone marrow stromal cell line QXMSC1-IL-2 + IL-3 on the reconstitution of T-cell immunity in allo-BMT mice. METHODS: The bone marrow stromal cell line QXMSC1 was co-transfected with IL-2 and IL-3 genes using a Tet-on gene expression system. T lymphocyte subset counts per spleen were analyzed by flow cytometry. Lymphocyte proliferation response to ConA was examined to evaluate T-cell function. CDR3 spectratyping techniques were performed to evaluate TCR repertoire diversity at various time points post-transplantation. RESULTS: Gene engineered bone marrow stromal cell line QXMSC1-IL-2 + IL-3 could express IL-2 and IL-3 [1,300 ng.day(-1).10(-6) cells and 1100 ng.day(-1).10(-6) cells, respectively] under the control of doxycycline. QXMSC1-IL-2 + IL-3 in combination with allogeneic bone marrow could significantly increase the counts of CD(4)(+) and CD(8)(+) T cell, 1.72 and 1.27-fold respectively at week 3 compared with TCD-BMT group (P < 0.01); make CD(4)(+)/CD(8)(+) ratio return to normal level at week 4; enhance splenocytes mitotic response to ConA (P < 0.01), and accelerate restoration of TCR repertoire diversity in the lethally irradiated mice (P < 0.05). CONCLUSION: The gene transduced stromal cell line QXMSC1-IL-2 + IL-3 is able to accelerate T-cell immunity in allo-BMT mice.

Animals↗

Decomposition characteristics of toluene by a corona radical shower system.

Non-thermal plasma technologies offer an innovative approach to decomposing various volatile organic compounds(VOCs). The decomposition of toluene from simulated flue gas was investigated using a pipe electrode with nozzles for the generation of free radicals. Corona characteristics and decomposition of toluene were investigated experimentally. In addition, the decomposition mechanism of toluene was explored in view of reaction rate. The experimental results showed that the humidity of additional gas has an important effect on corona characteristics and modes and stable streamer corona can be generated through optimizing flow rate and humidity of additional gas. Applied voltage, concentration of toluene, humidity of toluene and resident time are some important factors affecting decomposition efficiency. Under optimizing conditions, the decomposition efficiency of toluene can reach 80%. These results can give a conclusion that the corona radical shower technology is feasible and effective on the removal of toluene in the flue gas.

Air Pollution↗

[Selection of sodium chloride tolerant mutants in Chrysanthemum morifolium in Anhui].

OBJECTIVE: To select the sodium chloride tolerant mutants of the Chrysanthemum morifolium callus through tissue culture and EMS (ethylmethane sulfonate) treatment. METHOD: Calli were induced from the leaves of C. morifolium. The calli were treated with 0.2% and 0.5% EMS, respectively. After 15 days' culture, the calli were transplanted to selection media with 0.5%, 1.0% and 1.5% NaCl, and the sodium chloride tolerant mutants were selected out. RESULT AND CONCLUSION: After tested the sodium chloride tolerant stability, the callus selected are found to be the mutants indeed.

Chrysanthemum↗

[Prognostic value of MRI and 1H MRS in patients with temporal lobe epilepsy].

OBJECTIVE: To evaluate the prognostic value of hippocampal MRI scan, MRI volumetry and 1H MRS in patients with temporal lobe epilepsy (TLE). METHODS: 50 intractable TLE patients operated in Huashan hospital were studied. Before surgery, traditional MRI scans were used to exclude tumor and vascular malformation of the brain. All patients were examined by tilted coronal images which were perpendicular to the long axis of the hippocampus, using T1-weighted, T2-weighted and FLAIR sequence. MRI volumetric measurement of both hippocampal formation were performed. 38 patients also took 1H MRS scan. Unilateral anterior temporal lobectomy was performed in all patients and pathology showed different degrees of hippocampal sclerosis. The prognosis was categorized into three grades with grade I being assigned to the group of good outcome, and grade II and III being assigned to the bad outcome group. Correlative analysis between the results of several examinations and the prognosis were performed respectively. RESULTS: MRI-positive cases with hippocampal scans were about 84% of the 50 cases. Hippocampal atrophy, increase of signal intensity or the loss of internal morphological structure were detected. 98% of the MRI-positive patients had good outcome, and 38% of the MRI-negative patients had good outcome. The prognosis between MRI-positive group and MRI-negative group had significant difference (chi(2) = 23.00, P = 0.000). Among the right-side operated cases, the average hippocampal volume on the operated side of the bad outcome group was larger than that of the good outcome group. While among the left-side operated cases, the hippocampal volume on the non-operated side of the bad outcome group was smaller than that of the good outcome group. Significant differences were found in statistics respectively. In both groups, prognosis was found to be statistically related to the DHF value (difference of bilateral hippocampal volume). The DHF value of the good outcome group was larger than that of the bad outcome group. 38 patients took 1H MRS examination. The average NAA/(Cr + Cho) ratio on the operated side of the patients in the bad outcome group was greater than that of the good outcome group. The average NAA/(Cr + Cho) ratio on the contralateral side of the patients in the bad outcome group was lower than that of the good outcome group. But no significant differences were found in statistics respectively. 90% cases of MRS unilateral abnormalities had good outcome, while 77% cases of MRS bilateral abnormalities had good outcome. But no statistically significant difference was found among different groups (chi(2) = 0.493, P = 0.781). CONCLUSION: Hippocampal MRI scan, MRI volumetry and 1H MRS may be used as prognostic tools in TLE patients before surgery. The combination of several noninvasive methods before surgery can help choose suitable patients for surgery, and, as a result, improve surgical outcome.

Adolescent↗

Risk of second primary cancer in the contralateral breast in women treated for early-stage breast cancer: a population-based study.

PURPOSE: To study the potential risk factors, including radiotherapy (RT) for contralateral breast cancer (CBC), in patients treated for early-stage breast cancer. METHODS AND MATERIALS: The Surveillance, Epidemiology, and End Results database (1973-1996) was used to study the incidence of CBC after breast cancer. The Cox proportional hazards regression model was used to estimate the relative risk (RR) of CBC, with adjustment for confounders, including age, race, histologic subtype, and use of RT. Information on the use of hormonal therapy and chemotherapy was not available in the Surveillance, Epidemiology, and End Results database. RESULTS: A CBC was documented in 5679 (4.2%) of the 134501 localized invasive or intraductal breast cancer patients surviving at least 3 months. The 10- and 20-year actuarial rate of CBC was 6.1% and 12%, respectively. In multivariate analysis, medullary carcinoma (RR = 1.18, 95% confidence interval [CI] 1.02-1.37), black race (RR = 1.20, 95% CI 1.08-1.33), and age >55 years at initial diagnosis (RR = 1.15, 95% CI 1.08-1.22) were associated with increased CBC risk. A total of 1234 (3.3%) of 37,379 patients who received RT developed CBC, and 4445 (4.6%) of 97122 patients who did not receive RT developed CBC. Overall, RT was not associated with an increased risk of CBC (RR = 1.04, 95% CI 0.97-1.10) in multivariate analysis. The CBC risk associated with RT varied substantially with the length of follow-up. During the first 5 years of follow-up, RT was not associated with an increased CBC risk (age-adjusted RR = 0.96, 95% CI 0.88-1.04). For patients surviving for >5 years, RT was associated with a 14% increase in CBC risk (RR = 1.14, 95% CI 1.03-1.26). The increased CBC risk with RT was evident in patients aged <45 years (RR = 1.32, p = 0.01) and >55 years (RR = 1.15, p = 0.04) at initial diagnosis. The 5-, 10-, 15-, and 20-year actuarial rate of CBC was 2.9%, 6.5%, 10.2%, and 13.4%, respectively, for patients with RT; the corresponding rates were 3.0%, 6.0%, 8.9%, and 11.8% for patients without RT. The absolute increase in CBC risk associated with RT was 0.5%, 1.3%, and 1.6% in the 10-, 15-, and 20-year actuarial rate, respectively. CONCLUSION: CBC is not uncommon after breast cancer, especially for certain subsets of patients. RT was associated with a very small increased long-term CBC risk. This minimal increase in CBC risk should not affect clinical decision-making in treatment selection for patients with localized invasive breast cancer or ductal carcinoma in situ. Unnecessary radiation exposure to the contralateral breast should be avoided for all patients with early-stage breast cancer.

Age Factors↗

Second primary cancers in patients with laryngeal cancer: a population-based study.

BACKGROUND: Literature regarding incidence of site-specific second cancers after laryngeal cancer is limited. Risk factors associated with second primaries are unknown. METHODS: Second primaries after laryngeal cancer in the SEER database (1973-1996) were analyzed for incidence, relative risk compared with the general population, and potential risk factors, including radiotherapy. Information on chemotherapy and tobacco smoking was not available in the SEER database. RESULTS: Of 20,074 laryngeal cancer patients surviving at least 3 months, 3533 (17.6%) developed second cancers. The cumulative risk of developing a second cancer was 26% at 10 years and 47% at 20 years. Compared with age-adjusted, gender, and tumor-specific rates in the general population, laryngeal cancer patients had higher risks of second cancers overall (observed-to-expected ratio [O/E] = 1.68, 95% confidence interval [CI] = 1.58-1.79), head-and-neck (4.81 [4.31-5.58]), esophageal (3.99 [3.29-4.83]), and lung (3.56 [3.34-3.79]) cancer. Advanced age at initial diagnosis was associated with increased risks of second cancers (p = 0.0001). Radiotherapy was associated with increased risk of second cancers overall (relative risk [RR] = 1.10 [1.02-1.18], p = 0.012), especially second cancers of the lung (RR = 1.18, [1.05-1.33], p = 0.006) and possibly second cancers of the head and neck (RR = 1.26, [0.99-1.60], p = 0.061). Radiotherapy was associated with a 68% excess risk (RR = 1.68, [1.16-2.43], p = 0.007) of developing a second head-and-neck cancer in patients who survived more than 5 years. Second primary was associated with a poor survival (p = 0.0001). CONCLUSIONS: Second cancers after laryngeal cancer are common, especially for long-term survivors. Radiotherapy was associated with a small increased risk of developing second cancers overall and long-term risk of head-and-neck cancers. This data should be interpreted with caution in light of the lack of information on chemotherapy and tobacco smoking in the SEER database. Prevention and early detection are indicated.

Analysis of Variance↗

Actions of cysteinyl leukotrienes in the enteric nervous system of guinea-pig stomach and small intestine.

Conventional intracellular microelectrodes, neuronal tracer injection techniques and immunohistochemistry were used to study the actions of cysteinyl leukotrienes (CysLTs) on electrical and synaptic behavior of enteric neurons in guinea-pig stomach and small intestine. Bath application of leukotriene C(4), leukotriene D(4) or leukotriene E(4) evoked a slowly activating depolarizing response in most of the myenteric and submucous plexus neurons in the small intestine while no effect was observed in gastric neurons. The depolarization evoked by cysteinyl leukotrienes in intestinal neurons was associated with increased input resistance and enhanced excitability. Suppression of hyperpolarizing after-potentials occurred in AH type neurons. The depolarizing action of cysteinyl leukotrienes was resistant to tetrodotoxin and cyclooxygenase inhibitors. Neither the CysLT(1) receptor antagonists (E)-3-[[[3-[2-(7-chloro-2-quinolinyl)ethenyl]phenyl][[3-dimethylamino)-3-oxopropyl]thio]methyl]thio]-propanoic acid (MK 571), 1-[2-hydroxy-3-propyl-4-[4-(1H-tetrazol-5-yl)butoxy]phenyl]-ethanone (LY 171883) and alpha-pentyl-3-(2-quinolinylmethoxy)-benzenemethanol (REV 5901), nor the dual CysLT(1)/CysLT(2) receptor antagonist 6(R)-(4'-carboxyphenylthio)-5(S)-hydroxy-7(E),9(E),11(Z),14(Z)-eicosatetraenoic acid (BAY u9773) significantly altered the depolarizing action of the cysteinyl leukotrienes. Neurotransmission was unaffected by the cysteinyl leukotrienes. The results suggested involvement of cysteinyl leukotrienes in enteric immuno-neural communication through excitatory actions on enteric neurons. The receptor mediating these effects was distinct from currently recognized cysteinyl leukotriene receptor subtypes (CysLT(1) and CysLT(2) receptors) and may represent a new receptor subtype.

Acetophenones↗

Integrin-mediated targeting of drug delivery to irradiated tumor blood vessels.

The objective of this study was to target drug delivery to radiation-induced neoantigens, which include activated receptors within the tumor vasculature. These responses include posttranslational changes in pre-existing proteins, which can be discovered by phage-displayed peptide libraries administered to mice bearing irradiated tumors. Phage-displayed peptides recovered from irradiated tumors included the amino acid sequence RGDGSSV. This peptide binds to integrins within the tumor microvasculature. Immunohistochemical staining of irradiated tumors showed accumulation of fibrinogen receptor alpha(2b)beta(3) integrin. We studied tumor targeting efficiency of ligands to radiation-induced alpha(2b)beta(3). Radiopharmaceuticals were localized to irradiated tumors by use of alpha(2b)beta(3) ligands conjugated to nanoparticles and liposomes. Fibrinogen-conjugated nanoparticles bind to the radiation-activated receptor, obliterate tumor blood flow, and significantly increase regression and growth delay in irradiated tumors. Radiation-guided drug delivery to tumor blood vessels is a novel paradigm for targeted drug delivery.

Albumins↗

Simultaneous administration of a low-dose mixture of donor bone marrow cells and splenocytes plus adenovirus containing the CTLA4Ig gene result in stable mixed chimerism and long-term survival of cardiac allograft in rats.

T-cell costimulatory blockade combined with donor bone marrow transfusion may induce mixed chimerism, rendering robust tolerance in transplanted organs and cells. However, most protocols entail high doses of donor bone marrow cells (BMCs) or repeated administration of costly agents that block costimulatory pathways, thus delaying clinical development. To circumvent these shortcomings, we developed a strategy in which the dosage of donor BMCs was reduced but compensated by donor splenocytes (SPLCs). Furthermore, repeated administration of costly agents was replaced with a single injection of adenovirus expressing a gene of interest. In rat cardiac transplantation models, cardiac allografts from DA (RT-1a) rats were transplanted heterotopically into the abdomen of LEW (RT-11) recipient rats. Immediately after cardiac transplantation, an adenovirus vector (AdCTLA4Ig; 5 x 10(9) plaque-forming units) containing the gene for CTLA4Ig was administered to recipients (n = 6) simultaneously with a low dose of donor BMCs (1 x 10(8)/rat) and SPLCs (5 x 10(7)/rat) via the portal vein. The treated LEW recipient rats developed long-lasting mixed chimerism (>10% at >100 days) and exhibited long-term cardiac allografts (mean survival time of > 200 days) compared with control recipients. Moreover, recipients displaying long-lasting mixed chimerism accepted subsequent donor skin allografts while promptly rejecting third-party skin allografts. These results suggest that blockade of the CD28-B7 pathway, using adenovirus-mediated CTLA4Ig gene transfer, in concert with a low dosage of donor BMCs and SPLCs, may represent a feasible strategy to induce stable mixed chimerism and permit long-term survival of cardiac allografts.

Abatacept↗

Dietary pattern is associated with homocysteine and B vitamin status in an urban Chinese population.

To identify existing dietary patterns and examine associations between these patterns and plasma homocysteine and B vitamin concentrations in an urban Chinese population living in Beijing (n = 119), dietary information was collected with a food frequency questionnaire designed for this population. Plasma homocysteine and B vitamin concentrations were examined. Food group variables, expressed as percentages of total energy intake, were entered into cluster analysis to define three distinct dietary pattern groups. The prevalence of high homocysteine (>11 micromol/L for women and 12 micromol/L for men), was 31.9%; of low folate (<6.8 nmol/L), 36.2%; of low vitamin B-12 (<221 pmol/L), 36.9%; and of low vitamin B-6 (<30 nmol/L), 16.0%. The three dietary patterns derived were defined by relatively greater intake of 1) fruit and milk, 2) red meat and 3) refined cereals. More than 40% of subjects in the refined cereals group had high plasma homocysteine and low plasma folate concentrations, and 67% had low plasma vitamin B-12 concentrations. Those following the refined cereals pattern were 4 and 5.2 times more likely to have high homocysteine and low vitamin B-12 concentrations, respectively, relative to the fruit and milk dietary pattern group (P < 0.01), after adjustment for potential confounders. High intake of refined cereals was associated with low B vitamin and high homocysteine concentrations, whereas the pattern high in fruit and milk was associated with the lowest homocysteine. Dietary patterns appear to play an important role in the micronutrient and homocysteine status of these Chinese adults.

Adult↗

Translational recoding signals between gag and pol in diverse LTR retrotransposons.

Because of their compact genomes, retroelements (including retrotransposons and retroviruses) employ a variety of translational recoding mechanisms to express Gag and Pol. To assess the diversity of recoding strategies, we surveyed gag/pol gene organization among retroelements from diverse host species, including elements exhaustively recovered from the genome sequences of Caenorhabditis elegans, Drosophila melanogaster, Schizosaccharomyces pombe, Candida albicans, and Arabidopsis thaliana. In contrast to the retroviruses, which typically encode pol in the -1 frame relative to gag, nearly half of the retroelements surveyed encode a single gag-pol open reading frame. This was particularly true for the Ty1/copia group retroelements. Most animal Ty3/gypsy retroelements, on the other hand, encode gag and pol in separate reading frames, and likely express Pol through +1 or -1 frameshifting. Conserved sequences conforming to slippery sites that specify viral ribosomal frameshifting were identified among retroelements with pol in the -1 frame. None of the plant retroelements encoded pol in the -1 frame relative to gag; however, two closely related plant Ty3/gypsy elements encode pol in the +1 frame. Interestingly, a group of plant Ty1/copia retroelements encode pol either in a +1 frame relative to gag or in two nonoverlapping reading frames. These retroelements have a conserved stem-loop at the end of gag, and likely express pol either by a novel means of internal ribosomal entry or by a bypass mechanism.

Base Sequence↗

Cationic transfection lipids.

This review focuses on the recent developments in study of cationic lipids as carriers for DNA delivery. Emphasis is placed on a class of compounds as exemplifies by their similarity in structures and transfection activities. The technical aspects are also reviewed on how to prepare DNA-lipid complexes and to perform transfection. A brief discussion of the current views on the mechanism of cationic lipid-mediated DNA transfer is intended to provide new prospects for future developments and further improvement of the current systems.

Animals↗