Biomedical subjects

Q Luo

Publications and source records attributed to Q Luo.

At least 19 recordsLinked to original sources

PubMed2002

Wave dispersion in gyrotropic relativistic pulsar plasmas.

Wave dispersion in a gyrotropic relativistic pulsar plasma is discussed. A pulsar plasma in general contains electrons, positrons, and possibly ions. Although electron-positron pairs are dominant in number density, charge neutrality is generally not satisfied and the gyrotropic terms need to be considered. These gyrotropic terms can lead to elliptical polarization that may be relevant for the observed circular polarization of pulsar radio emission. The wave dispersion and polarization are obtained numerically by calculating the response in terms of the three relativistic plasma dispersion functions. For waves propagating at an oblique angle (to the ambient magnetic field) a significant ellipticity requires the plasma to deviate substantially from the neutrality condition.

Journal Article↗

PubMed2002

Quantification and reduction of organic sulfur compound formation in a commercial wood pulping process.

This study experimentally quantified the formation of organic sulfur compounds in a commercial SuperBatch kraft pulping process using a laboratory pilot-scale digester. The results indicate that wood chips not only can adsorb HS- but also methyl mercaptan (MM) in the black liquor used for pretreatment during the two pretreatment stages. The absorption rate of MM is much faster than that of HS-. In the third stage of SuperBatch pulping, the rate of formation of MM and dimethyl sulfide (DMS) is very similar to that found in conventional batch kraft pulping processes. The study examined the applicability of the phase transition cooking (PTC) concept for reducing organic sulfur compounds in pulping, previously developed in laboratory batch pulping using a bomb-type digester, in a SuperBatch process. It was confirmed that there is a phase transition point (PTP) corresponding to PTC in SuperBatch pulping beyond which further delignification significantly increases the formation of volatile organic sulfur compounds. The results indicate that a 40% reduction of TRS formation can be achieved by using PTC.

Adsorption↗

PubMed2002

Quasilinear diffusion as a result of modulational instability in the pulsar plasma.

Quasilinear diffusion due to modulational instability is considered in this paper. Interaction between the high-frequency, nearly transverse O mode (or the transverse X mode) and the low-frequency, nearly longitudinal L-O mode in a pulsar magnetospheric pair plasma can lead to modulational instability. The low-frequency L-O mode is superluminal, which is not subjected to usual Landau damping, and it is possible that excess wave energy is stored in this superluminal mode. The superluminal low-frequency L-O mode can dissipate in a way similar to the process of Langmuir wave collapse, that is, it cascades from the long- to short-wavelength regimes. When the phase speed becomes less than c, the waves can be damped through various resonances. We consider, in particular, damping through cyclotron resonance, which can lead to particle acceleration. The energetic beam particles, which have a very small spread initially, can develop a high-energy distribution tail, acquiring pitch angles through quasilinear diffusion. These particles can emit gamma rays through synchrotron radiation, contributing to the observed pulsar high-energy emission.

Journal Article↗

PubMed2002

Multiple headspace extraction-gas chromatographic method for the study of process kinetics.

A multiple headspace extraction gas chromatographic technique to automate the study of process kinetics that involves volatile species was developed in this study. The technique was demonstrated by using it to study methanol formation in kraft black liquor samples under an isothermal temperature of 70 degrees C. The results indicate that methanol formation in kraft black liquors under isothermal conditions follows an exponential decay function. The present method is very simple, efficient and fully automated. It can be easily applied to study slow kinetic processes, such as reaction or adsorption and desorption, involving volatile species in any environmental and industrial samples with complicated matrices.

Chromatography, Gas↗

PubMed2001

Affinity membrane chromatography for the analysis and purification of proteins.

Affinity chromatography is unique among separation methods as it is the only technique that permits the purification of proteins based on biological functions rather than individual physical or chemical properties. The high specificity of affinity chromatography is due to the strong interaction between the ligand and the proteins of interest. Membrane separation allows the processing of a large amount of sample in a relatively short time owing to its structure, which provides a system with rapid reaction kinetics. The integration of membrane and affinity chromatography provides a number of advantages over traditional affinity chromatography with porous-bead packed columns, especially with regard to time and recovery of activity. This review gives detailed descriptions of materials used as membrane substrates, preparation of basic membranes, coupling of affinity ligands to membrane supports, and categories of affinity membrane cartridges. It also summarizes the applications of cellulose/glycidyl methacrylate composite membranes for proteins separation developed in our laboratory.

Binding Sites↗

PubMed2001

CCR5 and CXCR4 expression correlated with X4 and R5 HIV-1 infection yet not sustained replication in Th1 and Th2 cells.

OBJECTIVE: To investigate the infectivity of T-helper (Th)1 and Th2 cells (derived from ccr5 wild-type and homozygous ccr5 Delta 32) to R5 and X4 HIV-1. DESIGN: It remains unclear whether infection of Th1 and Th2 CD4 cells by R5 and X4 viruses mirrors their co-receptor expression profile as no direct quantitation of coreceptor levels and infection has been performed. In addition, it is unknown whether the lack of CCR5 expression affects the degree of Th1/Th2 polarization. METHODS: Surface expression of CCR5 and CXCR4 was determined by quantitative fluorescence activated cell sorter analysis on in vitro differentiated Th1 and Th2 cells. R5 (Ba-L) and X4 (IIIB) HIV-1 isolates were used for infection studies and the efficiency of viral entry was determined by quantitative real time polymerase chain reaction detection of reverse transcribed proviral DNA. RESULTS: Cell surface density of CCR5 molecules was eight-fold higher in Th1 versus Th2 subsets (P = 0.005) whereas CXCR4 surface density was four-fold higher in Th2 versus Th1 subsets (P = 0.006). Preferential infection and entry of Th1 cells by R5 HIV-1 was not associated with preferential replication, as eventually the R5-virus replicated to a higher level in Th2 cells in spite of lower initial viral infection/entry. By contrast, Th2 cells preferentially supported X4-virus infection and replication. High beta chemokine secretion by Th1 cells was associated with a lower R5 replication rate. CONCLUSIONS: Th1 and Th2 cells differ in their infection efficiency for R5 and X4 HIV-1. ccr5 Delta 32-homozygous individuals maintain the ability for Th1/Th2 polarization, i.e., the expression of CCR5 is not required for Th1/Th2 polarization.

Cell Line↗

PubMed2001

Chromatographic separation of proteins on metal immobilized iminodiacetic acid-bound molded monolithic rods of macroporous poly(glycidyl methacrylate-co-ethylene dimethacrylate).

Continuous rod of macroporous poly(glycidyl methacrylate-co-ethylene dimethacrylate) was prepared by a free radical polymerization within the confines of a stainless-steel column. The epoxide groups of the rod were modified by a reaction with iminodiacetic acid (IDA) that affords the active site to form metal IDA chelates used for immobilized metal affinity chromatography (IMAC). The efficiency of coupling of IDA to the epoxide-contained matrix was studied as a function of reaction time and temperature. High-performance separation of proteins, based on immobilized different metals on the column, were described. The influence of pH on the adsorption capacity of bovine serum albumin on the Cu2+-IDA continuous rod column was investigated in the range from 5.0 to 9.0. Purification of lysozyme from egg white and human serum albumin (HSA) on the commercially available HSA solution were performed on the naked IDA and Cu2+-IDA continuous rod columns, respectively; and the purity of the obtained fractions was detected by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry.

Chromatography, Affinity↗

PubMed2001

[Relation between BDNF and synaptic reorganization of hippocampal mossy fibers].

OBJECTIVE: To investigate the relation between brain-derived neurotrophic factor (BDNF) and synaptic reorganization of hippocampal fibers (MF). METHODS: Antisense or sense oligomucleotides to BDNF and/or PBS buffer were injected into the cerebal ventricles of rats of epileptic model induced by kainic acid (KA) and control rats respectively. Immunohistochemical staining and Timm's silver sulfide staining were used to examine the effect of antisense oligonucleotides to BDNF upon the MF sprouting in the KA model and control rats. RESULTS: Timm's staining showed that multiple aberrant Timm's granules were found in the inner molecular layer (IML) of the dentate gyrus of hippocampus of the KA model rats intracerebroventricularly injected with sense oligonucleotides to BDNF or PBS, less aberrant Timm's granules were found in the hippocampal IML of KA model rats intracerebroventricularly injected with antisense oligonucleotides to BDNF, and no aberrant Timm's granule was found in the hippocampal IML of non-KA model rats intracerebroventricular injected with antisense oligonucleotides to BDNF. Immunohistochemical staining showed multiple BDNF immunologically labeled neurons in the hilus and CA3 region of hippocampus of KA model rats intracerebroventricularly injected with sense oligonucleotides to BDNF and PBS, less in the KA model rats intracerebroventricularly injected with antisense oligonucleotides to BDNF, and only a few in the non-KA model rats. The A value in both Timm's and immunohistochemical sections of KA model rats was higher than that of non-KA model rats. The A value in both Timm's and immunohistochemical sections of KA model rats was significantly lower in the groups injected with antisense oligonucleotides to BDNF than in the group injected with sense oligonucleotides. CONCLUSION: BDNF may play an important role in promoting the MF sprouting caused by repeated epileptic convulsion in the course of MF synaptic reorganization. The expression of BDNF protein can be upregulated by subcutaneous injection of KA and be decreased by intracerebroventricular injection of antisense oligonucleotides to BDNF.

Animals↗

PubMed2001

Analysis of nonvolatile species in a complex matrix by headspace gas chromatography.

This study developed a phase reaction conversion (PRC) headspace gas chromatographic (HS-GC) technique for the measurements of nonvolatile species in liquid or solid samples. The technique is demonstrated by the measurements of carbonate in aqueous carbonate solutions and in kraft pulp mill liquor samples. A very small amount of sulfuric acid (volume of 0.5 ml, concentration of 2 mol/l) is used to acidify a sample of less than 300 microl in volume and convert the dissolved carbonate into carbon dioxide (gas) in a sample vial (reactor) that is analyzed by thermal conductivity detection through a headspace sampler. The carbonate concentrations measured by PRC-HS-GC in seven kraft liquor samples agree very well with those measured using a coulometric and a titrametric method. Simultaneous analysis of multiple species was also conducted to demonstrate the versatility of the method. The present method is very simple, rapid, reliable, accurate, and fully automated. It can be applied to analyze other nonvolatile species in various industrial and environmental samples.

Calibration↗

PubMed2001

Clinical study of scrotum scintigraphy in 49 patients with acute scrotal pain: a comparison with ultrasonography.

The significance of scrotum scintigraphy in differentiating acute testicular torsion from acute orchiepididymitis was evaluated. In this report, 49 patients with acute scrotal pain were examined with radionuclide scrotum scintigraphy and ultrasonography in parallel for comparison. Of 37 patients with decreased radioactivity in the abnormal side scrotum, 35 were diagnosed with testicular torsion surgically and the other 2 were diagnosed with indirect inguinal hernia. Only 17 among the 35 patients were diagnosed by ultrasonography as having testicular torsion. The remaining 12 patients with increased radioactivity in the abnormal side of the scrotum were all diagnosed with orchiepididymitis through conservative treatment and clinical follow-up, but only 8 of the 12 were correctly and exactly diagnosed by ultrasonography. In the process of diagnosing acute scrotal pain, radionuclide scrotum scintigraphy has obvious advantage over ultrasonography. It also has the advantage of being simple, fast and accurate but without any detrimental effect on the human body.

Adolescent↗

PubMed2001

Administration of plasmid DNA expressing human interleukin-6 significantly improves thrombocytopoiesis in irradiated mice.

When people are exposed to large doses of ionizing rays in a short time, hematopoiesis is impaired and hemorrhage is one of the major clinical features. Suddenly decreasing platelet counts are responsible for the life-threatening hemorrhagic complication. Therefore, some cytokines have been used to improve thrombocytopoiesis in various radiation-induced thrombocytopenia models. Current measures for this purpose involve repeated intravenous or subcutaneous injections of recombinant proteins, which are expensive and inconvenient, or gene therapy with viral vectors that could not obviate the risk of infection. We tried to determine the possibility of gene therapy with plasmid vectors for radiation-induced hematopoietic injury, which could overcome the above-mentioned problem. In this study, we describe the enhanced efficiency of radiation on gene transfer with plasmid vector in vivo and the physiological role of expressed human interleukin-6 (hIL-6) in vivo on a radiation-induced thrombocytopenia model. After a single intramuscular injection of plasmid hIL-6 DNA on 6.5-Gy-irradiated mice, the hIL-6 protein level in mouse plasma was determined with enzyme-linked immunosorbent assay (ELISA). The level of hIL-6 began to increase from the 4th day, reached the peak value on about the 11th day, and remained at a higher level on the 28th day. Meanwhile, unirradiated mice injected with the same amount of plasmid DNA showed less hIL-6 on the 11th day after administration. Further experiments demonstrated that the hIL-6 level in 7.5-Gy-irradiated mice was about three times higher than that of 5.0-Gy-irradiated mice, suggesting radiation could improve gene transfer efficiency of plasmid DNA in vivo and might be dependent on radiation doses. The expression of hIL-6 in vivo showed a significant effect on hematopoietic recovery after radiation. Not only the platelet nadir in peripheral blood, but also the number of colony-forming cells in bone marrow rose. The increased platelet counts were partially due to the increase of reticulated platelet that reflected the activity of a given population of megakaryocyte in bone marrow. We conclude that radiation could significantly enhance the gene transfer efficiency of plasmid DNA and that gene therapy with plasmid vectors for radiation-induced hematopoietic injury might be more effective than other diseases without DNA repair.

Animals↗

PubMed2001

[Study on the removal of arsenite from dispersed drinking water].

The feasible methods for oxidation and removal of arsenite[As(III)] from dispersed drinking water were based on the removal of arsenate[As(V)] by ferric sulfate. The results showed that the spotaneous oxidation of As(III) to As(V) was very slow and could not be enhanced by aerating for 24 h. The removal rate of As(III) could reach that of As(V) when pre-aerating water samples with ozone for 60 s, putting 7.5 ml/L hydrogen peroxide solution, adding 2.5 mg/L javelle water (sodium hypochlorite) or 15 mg/L bleaching powder(numerated by chlorine). The oxidation by using javelle water was rather stable when samples were varied in pH value, hardness, initial concentration of As(III) and As(III)/As(V) ratio. The effective oxidation could be reached with 1.25 mg/L javelle water when the initial concentration of As(III) was < or = 0.8 mg/L. Moreover, the field study also confirmed the oxidation effect of javelle water. It is suggested that javelle water is an effective, economic and technologic feasible oxidationagent for removing arsenite from dispersed drinking water.

Arsenites↗

PubMed2001

[Release character of phosphorus from the sediments of east Lake, Wuhan].

Effects of environmental factors on the release of phosphorus were studied at laboratory simulated test. The relationship between the different forms of phosphorus in sediments and the quantity of releasing phosphorus was studied at the same time. Results showed that the rates of phosphorus release from the sediment increased with rising the temperature of disturbing the overlying water. The content of phosphorus release from the sediment reached the lowest level when pH value was 7.4, high pH or low pH increased the rates of phosphorus release from the sediment. In anaerobic, the release rates of phosphorus was 30 times as much as in aerobic. Research also showed that different chemical forms of phosphorus in sediments were related to the quantity of phosphorus released from the sediments in varying degrees. The dissolved phosphorus and Fe binding phosphorus in sediments played the most important roles (r > 0.90, P < 0.01).

China↗

PubMed2001

Novel expression patterns of the myc/max/mad transcription factor network in developing murine prostate gland.

PURPOSE: Expression of myc proto-oncogenes and myc-antagonizing mad/mxi genes typically predominate in proliferating versus differentiating cells, respectively. C-myc expression in prostate cells is well established but to our knowledge that of several recently discovered mad/mxi genes is completely uncharacterized. Such characterization is particularly relevant because mxi1 is lost or mutated in some human prostate tumors and mouse mxi1-null mutants show prostatic hyperplasia. MATERIALS AND METHODS: Developing murine prostatic lobes at select postnatal days 1 to 28 were analyzed by in situ immunohistochemical and in vitro RNA analysis. The expression patterns of the 3 myc genes c-, L- and N-myc, and the mad1, mxi1 and mad4 genes were studied in most detail with nonradioactive in situ and immunohistochemical analyses. RESULTS: We describe what is to our knowledge previously unreported expression of N- and L-myc in the prostate with particularly the latter strongly expressed throughout development. High c-myc expression was lost at day 7 with re-elevation at day 14, followed by subsequent low expression, representing a unique in vivo confirmation of c-myc expression changes seen previously in several in vitro differentiation systems. The alternatively spliced weak and strong repressor mxi1 isoforms showed distinct, partially overlapping expression patterns. Of particular interest were continual mad1 and mad4 expression during the proliferative and differentiative phases. Similarly mad1 was evident in proliferating normal prostate cell cultures but not in tumor cell lines, suggesting that mad1 expression in prostate may be clinically relevant. CONCLUSIONS: Myc network expression in developing mouse prostate is novel and does not completely fit previous simpler models of Myc versus Mad expression based on other cell types.

Animals↗

PubMed2001

[Removal of arsenic from dispersed drinking water by iron oxide-coated sand].

The iron oxide-coated sand(IOCS) was developed by treating normal river sand with molysite and investigated by batch, column tests and autoptic experiment to evaluate it's ability of eliminating arsenic from dispersed drinking water. The results showed that IOCS was relatively stable and can be seen iron oxide distributedly patched the surface of sand by scan electron microscope. IOCS needn't any activation pretreatment. It reached the maximum adsorption within 30-60 min. The removal percentage of arsenate was decreased but the one of arsenite had little change when the pH varied from 5 to 9. And the arsenic adsorption matched the Langmuir isotherm. In 5 circles of runs, it treated 408-426 (arsenite) beds and 390-412(arsenate) beds volume of water with 75 g(50 ml) IOCS respectively when the influent arsenic concentration was 1.0 mg.L-1. And the arsenic percentage recovery was above 94% when regenerating the IOCS by 0.2 mol.L-1 NaOH. The home simulation unit contained IOCS 3.0 kg produced 209 L and 198 L, 196 L and 185 L of water when the influent arsenate or arsenite concentration was 1.0 mg.L-1, and 200 L arsenic free water with the influent arsenic 0.202-1.733 mg.L-1 during the field experimental period. The water quality was not affected by the adsorbent. With low-cost and simple operation, the IOCS should be a promising novel medium for arsenic removal in dispersed drinking water.

Adsorption↗

PubMed2001

[The effect of rhIL-11 on hematopoiesis of rhesus monkeys irradiated with 60Co gamma-rays].

OBJECTIVE: To study the therapeutic effect of recombinant human interleukin-11 (rhIL-11) on acute radiation sickness in monkeys. METHODS: rhIL-11 (30, 60, 120 micrograms.kg-1.d-1, s.c., on days 0-13 after TBI) or vehicle was administered to rhesus monkeys irradiated with 3.0 Gy 60Co gamma-rays. RESULTS: The nadirs of platelet count were significantly improved after treatment with rhIL-11. The duration of platelet and leukocyte numbers below 50% of their baseline values was shortened. Erythrocyte recovery was also accelerated. Semi-solid bone marrow cell culture demonstrated that rhIL-11 could stimulate monkey's bone marrow cell to form more CFU-MK, CFU-Mix, CFU-E and BFU-E in vitro, especially at the dose of 60 micrograms.kg-1.d-1. Histopathological observation revealed that bone marrow of the untreated controls showed large area of bleeding whereas that of the rhIL-11 treated monkeys was in active proliferation. CONCLUSION: rhIL-11 can accelerate hematopoietic recovery of monkeys received 3.0 Gy total body gamma-rays irradiation.

Animals↗

PubMed2001

[An new filling material of hair for the application of plastic surgery].

OBJECTIVE: To investigate the possibility of hair as a filling material for reconstructive or cosmetic surgery. METHODS: Sterilized pellets of hairs and silicone were selected and implanted subcutaneously in white rabbits. The clinical trial was carried out in 3 cases. RESULTS: A thin fibrous capsule, with much few inflammatory cells, was formed around the implanted hair pellets in 3-4 months. The inflammatory cells disappeared in the 9th month. No implant rejection, granulomatous formation or hair degradation was showed. CONCLUSION: Hair may be a valuable filling material for augmentation of the soft tissue.

Adult↗

PubMed2001

[A study of adhesion molecule expression in extraocular muscles of Graves' ophthalmopathy].

OBJECTIVE: To investigate the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1) in extraocular muscles (EOM) of the eyes with Graves' ophthalmopathy (GO). METHODS: Seventeen EOM specimens obtained from 16 severe patients with GO and their cryostat sections were observed by double labeling immunohistochemical methods. RESULTS: The expression of ICAM-1 was observed in interstitial and perimysial connective tissue surrounding EOM fibers, mononuclear cells, fibroblasts and vascular endothelial cells. Only were vascular endothelial cells stained for VCAM-1, and ICAM-1 and VCAM-1 immunoreactivities were not detected in EOM cells. CONCLUSIONS: The findings indicate that ICAM-1 and VCAM-1 might be involved in the development of GO, and fibroblasts, vascular endothelial cells and mononuclear cells might play important roles in the autoimmune reaction.

Adult↗