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Biomedical subjects

Jing Liu

Publications and source records attributed to Jing Liu.

At least 199 records · Page 11Linked to original sources
PubMed2005

Neuroprotective effects of cyclooxygenase-2 inhibitor celecoxib against toxicity of LPS-stimulated macrophages toward motor neurons.

AIM: To establish an in vitro injured motor neuronal model and investigate the neuroprotective effects and possible mechanism of celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, on this model. METHODS: After macrophages were stimulated with lipopolysaccharide (LPS)+interferon-gamma (IFN-gamma) in the presence or absence of celecoxib for 24 h, the cell-free supernatant of LPS-stimulated macrophages was transferred to the culture of NSC34 cells. Viability of NSC34 cells was assessed by MTT assay after a further 24 h and 72 h incubation. After macrophages were stimulated by LPS+IFN-gamma for 12 h or 24 h, the release of prostaglandin E2 (PGE2), nitric oxide (NO), reactive oxygen species (ROS), tumor necrosis factor alpha (TNF-alpha) and interleukin-1beta (IL-1beta) from macrophages was measured by radioimmunoassay, Griess assay, fluorescence assay and enzyme-linked immunosorbent assay, respectively. The mRNA levels of COX-2, inducible nitric oxide synthase (iNOS), TNF-alpha and IL-1beta in macrophages were determined by reverse transcription-polymerase chain reaction after macrophages were stimulated for 6 h and 12 h. RESULTS: The supernatant of LPS-stimulated mouse macrophages induced the death of NSC34 cells and celecoxib protected the NSC34 cells against this toxicity. The LPS-induced increases in the release of PGE2, NO, TNF-alpha and IL-1beta from macrophages were attenuated by pre-treatment with celecoxib. However, celecoxib showed no effect on the ROS levels upregulated by LPS+IFN-gamma in the macrophage supernatant. The mRNA levels of COX-2, iNOS, TNF-alpha and IL-1beta were increased in LPS-activated macrophages and, except COX-2, reduced by pre-treatment with celecoxib. CONCLUSION: An in vitro injured motor neuronal model was established by using the toxicity of LPS-stimulated mouse macrophages toward motor neuronal NSC34 cells. In this model, celecoxib exerted neuroprotective effects on motor neurons via an inhibition of the neurotoxic secretions from activated macrophages.

Animals↗
PubMed2005

Numerical study on the thawing process of biological tissue induced by laser irradiation.

Most of the laser applications in medicine and biology involve thermal effects. The laser-tissue thermal interaction has therefore received more and more attentions in recent years. However, previous works were mainly focused on the case of laser heating on normal tissues (37 degrees C or above). To date, little is known on the mechanisms of laser heating on the frozen biological tissues. Several latest experimental investigations have demonstrated that lasers have great potentials in tissue cryopreservation. But the lack of theoretical interpretation limits its further application in this area. The present paper proposes a numerical model for the thawing of biological tissues caused by laser irradiation. The Monte Carlo approach and the effective heat capacity method are, respectively, employed to simulate the light propagation and solid-liquid phase change heat transfer. The proposed model has four important features: (1) the tissue is considered as a nonideal material, in which phase transition occurs over a wide temperature range; (2) the solid phase, transition phase, and the liquid phase have different thermophysical properties; (3) the variations in optical properties due to phase-change are also taken into consideration; and (4) the light distribution is changing continually with the advancement of the thawing fronts. To this end, 15 thawing-front geometric configurations are presented for the Monte Carlo simulation. The least-squares parabola fitting technique is applied to approximate the shape of the thawing front. And then, a detailed algorithm of calculating the photon reflection/refraction behaviors at the thawing front is described. Finally, we develop a coupled light/heat transport solution procedure for the laser-induced thawing of frozen tissues. The proposed model is compared with three test problems and good agreement is obtained. The calculated results show that the light reflectance/transmittance at the tissue surface are continually changing with the progression of the thawing fronts and that lasers provide a new heating method superior to conventional heating through surface conduction because it can achieve a uniform volumetric heating. Parametric studies are performed to test the influences of the optical properties of tissue on the thawing process. The proposed model is rather general in nature and therefore can be applied to other nonbiological problems as long as the materials are absorbing and scattering media.

Animals↗
PubMed2005

Alterations of natural killer cell and T-lymphocyte counts in adults infected with human immunodeficiency virus through blood and plasma sold in the past in China and in whom infection has progressed slowly over a long period.

Natural killer (NK) cells, natural killer T (NKT) cells, and T lymphocytes were analyzed by using a flow cytometer in 225 human immunodeficiency virus (HIV)-positive individuals infected through the past sale of blood and plasma without receiving antiretroviral therapy in the People's Republic of China. According to CD4 T-cell counts these HIV-infected adults were stratified into three groups: long-term slow progressors, HIV-infected subjects, and AIDS patients. NK cell counts in long-term slow progressors were higher compared to HIV infection and AIDS patients (P < 0.05) and lower compared to normal controls (P < 0.05), whereas NKT cell counts in slow progressors and the HIV infection group were not different from those of normal controls. NK cell counts in HIV-seropositive subjects were positively correlated with CD4 T-cell counts (P < 0.05), and NKT cell counts were positively correlated with CD4 T-cell and CD8 T-cell counts (P < 0.05). The CD8 T-cell counts were higher in slow progressors compared to those with HIV infection, AIDS patients, and normal controls. These results indicated that HIV infection causes alterations of NK cells and T cells in slow progressors, HIV-infected subjects, and AIDS patient groups, but no difference was found in NKT cell counts and percentages in slow progressors and the HIV-infected group compared to normal controls.

Adult↗
PubMed2005

Cardiac-specific overexpression of AT1 receptor mutant lacking G alpha q/G alpha i coupling causes hypertrophy and bradycardia in transgenic mice.

Ang II type 1 (AT1) receptors activate both conventional heterotrimeric G protein-dependent and unconventional G protein-independent mechanisms. We investigated how these different mechanisms activated by AT1 receptors affect growth and death of cardiac myocytes in vivo. Transgenic mice with cardiac-specific overexpression of WT AT1 receptor (AT1-WT; Tg-WT mice) or an AT1 receptor second intracellular loop mutant (AT1-i2m; Tg-i2m mice) selectively activating G(alpha)q/G(alpha)i-independent mechanisms were studied. Tg-i2m mice developed more severe cardiac hypertrophy and bradycardia coupled with lower cardiac function than Tg-WT mice. In contrast, Tg-WT mice exhibited more severe fibrosis and apoptosis than Tg-i2m mice. Chronic Ang II infusion induced greater cardiac hypertrophy in Tg-i2m compared with Tg-WT mice whereas acute Ang II administration caused an increase in heart rate in Tg-WT but not in Tg-i2m mice. Membrane translocation of PKCepsilon, cytoplasmic translocation of G(alpha)q, and nuclear localization of phospho-ERKs were observed only in Tg-WT mice while activation of Src and cytoplasmic accumulation of phospho-ERKs were greater in Tg-i2m mice, consistent with the notion that G(alpha)q/G(alpha)i-independent mechanisms are activated in Tg-i2m mice. Cultured myocytes expressing AT1-i2m exhibited a left and upward shift of the Ang II dose-response curve of hypertrophy compared with those expressing AT1-WT. Thus, the AT1 receptor mediates downstream signaling mechanisms through G(alpha)q/G(alpha)i-dependent and -independent mechanisms, which induce hypertrophy with a distinct phenotype.

Animals↗
PubMed2005

Identification of spatial genetic boundaries using a multifractal model in human population genetics.

There are two purposes in displaying spatial genetic structure. One is that a visual representation of the variation of the genetic variable should be provided in the contour map. The other is that spatial genetic structure should be reflected by the patterns or the gradients with genetic boundaries in the map. Nevertheless, most conventional interpolation methods, such as Cavalli-Sforza's method in genography, inverse distance-weighted methods, and the Kriging technique, focus only on the first primary purpose because of their arbitrary thresholds marked on the maps. In this paper we present an application of the contour area multifractal model (CAMM) to human population genetics. The method enables the analysis of the geographic distribution of a genetic marker and provides an insight into the spatial and geometric properties of obtained patterns. Furthermore, the CAMM may overcome some of the limitations of other interpolation techniques because no arbitrary thresholds are necessary in the computation of genetic boundaries. The CAMM is built by establishing power law relationships between the area A (> or =rho) in the contour map and the value p itself after plotting these values on a log-log graph. A series of straight-line segments can be fitted to the points on the log-log graph, each representing a power law relationship between the area A (> or =rho) and the cutoff genetic variable value for rho in a particular range. These straight-line segments can yield a group of cutoff values, which can be identified as the genetic boundaries that can classify the map of genetic variable into discrete genetic zones. These genetic zones usually correspond to spatial genetic structure on the landscape. To provide a better understanding of the interest in the CAMM approach, we analyze the spatial genetic structures of three loci (ABO, HLA-A, and TPOX) in China using the CAMM. Each synthetic principal component (SPC) contour map of the three loci is created by using both Han and minority groups data together. These contour maps all present an obvious geographic diversity, which gradually increases from north to south, and show that the genetic differences among populations in different districts of the same nationality are greater than those among different nationalities of the same district. It is surprising to find that both the value of p and the fractal dimension alpha have a clear north to south gradient for each locus, and the same clear boundary between southern and northern Asians in each contour map is still seen in the zone of the Yangtze River, although substantial population migrations have occurred because of war or famine in the last 2,000 or 3,000 years. A clear genetic boundary between Europeans and Asians in each contour map is still seen in northwestern China with a small value of alpha, although the genetic gradient caused by gene flow between Europeans and Asians has tended to show expansion from northwestern China. From the three contour maps another interesting result can be found: The values of alpha north of the Yangtze River are generally less than those south of the Yangtze River. This indicates that the genetic differences among the populations north of the Yangtze River are generally smaller than those in populations south of the Yangtze River.

ABO Blood-Group System↗
PubMed2005

Oxidative stress and neuronal death/survival signaling in cerebral ischemia.

It has been demonstrated by numerous studies that apoptotic cell death pathways are implicated in ischemic cerebral injury in ischemia models in vivo. Experimental ischemia and reperfusion models, such as transient focal/global ischemia in rodents, have been thoroughly studied and the numerous reports suggest the involvement of cell survival/death signaling pathways in the pathogenesis of apoptotic cell death in ischemic lesions. In these models, reoxygenation during reperfusion provides oxygen as a substrate for numerous enzymatic oxidation reactions and for mitochondrial oxidative phosphorylation to produce adenosine triphosphate. Oxygen radicals, the products of these biochemical and physiological reactions, are known to damage cellular lipids, proteins, and nucleic acids and to initiate cell signaling pathways after cerebral ischemia. Genetic manipulation of intrinsic antioxidants and factors in the signaling pathways has provided substantial understanding of the mechanisms involved in cell death/survival signaling pathways and the role of oxygen radicals in ischemic cerebral injury. Future studies of these pathways could provide novel therapeutic strategies in clinical stroke.

Animals↗
PubMed2005

[Changes of body mass index in a community cohort of Peking University from 1992 to 2002].

OBJECTIVES: To compare changes in body mass index (BMI), prevalence of over weight and obesity of the population in a community cohort of Peking University during 1992 to 2002, and to study their characteristics of individual BMI. METHODS: Totally, 1 985 individuals aged 35-64 years were selected from Peking University community with stratified random sampling method for baseline survey by physical examinations and questionnaire interviews to collect relevant data in 1992. And, a follow-up survey was conducted for each individual of the cohort in 2002. Data were analyzed for 1 437 individuals with complete records of the two surveys. RESULTS: (1) In the period from 1992 to 2002, weight increased averagely 4.89 kg in men and 3.08 kg in women, respectively, and BMI increased to 25.22 kg/m2 in 2002 from 23.49 kg/m2 ten years ago in men and to 25.02 kg/m2 from 23.30 kg/m2 in women. (2) Prevalence of overweight increased by 47.8% in men and 29.5% in women, and prevalence of obesity increased by 124.2% in men and 131.3% in women, respectively. (3) 74.9% of men with overweight ten years ago remained overweight and 22.9% of them became obese in 2002. 85.7% of men with obesity ten years ago remained obese in 2002. 58.2% of women with overweight ten years ago remained overweight and 34.5% of them became obese in 2002. 93.7% of women with obesity ten years ago remained obese in 2002. CONCLUSIONS: Mean BMI and prevalence of overweight and obesity of population in Peking University community increased during 1992 to 2002. Most of those with overweight or obesity ten years ago remained overweight or obese and few of them became normally weighed ten years later. Those with overweight BMI were more liable to become obese than those with normal BMI. All these results indicated once overweight or obesity established, it was difficult to be reversed. Therefore, the key to control overweight and obesity rests on its earlier prevention.

Adult↗
PubMed2005

[Observation on therapeutic effect of jianpi huoxue herbs combined with chemotherapy in treating post-operational colonic cancer patients].

OBJECTIVE: To observe and compare the therapeutic effect of Jianpi Huoxue herbs (JPHXH) combined with chemotherapy (CT) in treating post-operational colonic cancer patients with Pi deficiency Syndrome (PDS). METHODS: Adopting randomized control trial method, 64 patients were divided into two groups. The treated group (n = 43) received JPHXH plus CT and the control group ( n = 21 ) received CT alone. A treatment course of 3 months was applied to both groups. Therapeutic effect, changes of PDS and incidence of adverse reaction in the two groups were observed. RESULTS: The tumor remission rate in the treated group and the control group was 39.5 % and 33.3 %, respectively. The effective rate on PDS in the treated group and the control group was 72.1% and 19.0%, respectively, showing significant difference (P < 0.01). The incidence of adverse reaction was lower in the treated group than that in the control group (P < 0.05). CONCLUSION: JPHXH is effective in treating post-operational colonic cancer patients with PDS and relieving the adverse reaction of chemotherapy to certain extent.

Adenocarcinoma↗
PubMed2005

[Collisional excitation transfer between Na2(B 1pi(u)) and Na2(2 1sigma(g)+)].

The B 1pi(u) electronic state of Na2 was excited by the 441.6 nm He-Cd laser line. The Na atomic transitions and the A 1sigma(u)+ --> X 1sigma(g)+ band of Na2 were recorded. From the intensities and spectra of the Na and Na2 fluorescence several collisional processes in the excited sodium atom-dimer system were identified. The Na atomic lines are the result of collisional energy transfer from Na2 (B 1pi(u)) to Na(3P). Predissociation process may also contribute to atomic fluorescence. The A 1sigma(u)+ --> X 1sigma(g)+ band is interpreted through a populating mechanism involving collisional transfer from B 1pi(u) to 2 1sigma(g)+ followed by a radiative transfer to the A 1sigma(u)+ state. From the decay constants and fluorescence intensities, the rate coefficient at 360 degrees C for collisional energy transfer from Na2 (B 1pi(u)) to Na2 (2 1sigma(g)+) was found to be 5.7 x 10(-10) cm3 x s(-1). The predissociation rate of the B 1pi(u) is 2.7 x 10(6) s(-1).

Algorithms↗
PubMed2005

[Study on cloning of sisomicin-resistant gene (sisR) from Micromonospora inyoensis].

A new sisomicin resistance gene sisR was cloned from sisomicin-producing Micromonospora inyoensis. The sisR fragment was obtained by PCR amplification. The primer pairs were designed based on grm gene sequence from gentamicin-producing Micromonospora purpurea. The template DNA was isolated from Micromonospora inyoensis. A series of different DNA fragments were amplified by PCR, which were sub-cloned to vector pUC19 for further identification. It was found that five specific transformants containing target DNA fragments could resist high concentrations of sisomicin (over 1000 microg/mL sisomicin). One of them designated as sisR, was then sequenced and the alignment among sisR and other related genes showed that sisR gene differs from any known genes. It was concluded that sisR gene is a sequence that has not been reported so far.

Anti-Bacterial Agents↗
PubMed2005

[Chlorogenic acid content comparison of different processed products of Ilex hainanensis Merr].

OBJECTIVE: To control different processed products of Ilex hainanensis Merr quality. METHODS: Using HPLC to determine chlorogenic acid of Ilex hainanensis Merr. Measure wavelength is 327 nm. RESULTS: The linear range of chlorogenic acid was good from 0.84 microg to 5.04 microg (r = 0.9996). The average recovery was 100.46% (RSD = 1.33%). CONCLUSION: This method is convenient, fast, accurate, can be applied to quality control of the different processed products of Ilex hainanensis Merr.

Chlorogenic Acid↗
PubMed2005

[Establishment and optimization of the regeneration system for common dandelion (Taraxacum officinale Weber)].

A protocol is presented for direct and indirect regeneration of common dandelion (Taraxacum officinale Weber) from leaf and petiole explants. Multiple shoots were obtained on MS medium containing 0.2 mg/L IAA and 1 mg/L TDZ. For indirect regeneration, fragile calli were obtained from leaf and petiole explants on MS medium supplemented with 0.5 mg/L 2,4-D and 2.0 mg/L 6-BA. Regenerated plantlets were obtained when these calli were cultured on MS medium containing 1.0 mg/L 6-BA. Random amplified polymorphic DNA (RAPD) analysis of nine regenerated plantlets revealed 61 scorable bands from 10 primers, including three specific bands.

Culture Media↗
PubMed2005

[Combined use of TUVP and TURP for prostate cancer with bladder outlet obstruction].

OBJECTIVE: To investigate a new surgical method for the treatment of prostate cancer with bladder outlet obstruction. METHODS: Forty-seven patients with prostate cancer complicated with bladder outlet obstruction were treated by combined use of transurethral electrovaporization ablation of the prostate (TUVP) and transurethral resection of the prostate (TURP). RESULTS: The operations were successful, with satisfactory results and no serious complication. IPSS decreased from (26.5 +/- 4.8) pre-operatively to (8.5 +/- 2.2) post-operatively (P < 0.05); Qmax increased from (4.6 +/- 1.5) ml/s to (14.5 +/- 3.6) ml/s (P < 0.05); and PSA decreased from (58.1 +/- 7.2) microg/L to (3.6 +/- 1.8) microg/L (P < 0.01). CONCLUSION: The combined use of TUVP and TURP is a safe and ideal method for the treatment of prostate cancer with bladder outlet obstruction.

Aged↗
PubMed2005

[Association between the metabolic syndrome and free fatty acid].

OBJECTIVE: To explore the association of free fatty acid (FFA) with the metabolic syndrome (MS) and its components. METHODS: A cross-sectional study on cardiovascular risk factors was carried out in a natural population of Beijing in 1999, recruited by a stratified-random sampling method. The association of FFA with MS and its components was analyzed in a sample of 997 subjects aged 35-64 years. RESULTS: (1) The prevalence of MS increased with FFA level. (2) After adjustment for age, sex, smoking, alcohol consumption, body mass index (BMI) and insulin resistance index using a multi-variable logistic regression, FFA was significantly associated with MS. The odds ratio (OR) for the second, third, and fourth quartiles of FFA was 3.1, 3.1 and 4.1, respectively (all P < 0.001). (3) FFA correlated significantly with triglycerides (TG), glucose, systolic blood pressure, diastolic blood pressure, and waist circumference in the correlation analysis (all P < 0.001). The strongest correlation was found between FFA and TG, but no significant correlation was found between FFA and high-density lipoprotein cholesterol (HDL-C). (4) After adjustment for other factors in the logistic regression, FFA was significantly associated with central obesity, hypertriglyceridemia, hypertension, and hyperglycemia, but not with low HDL-C. (5) After adjustment for FFA, BMI and other factors, insulin resistance was also associated with central obesity, hypertriglyceridemia, low HDL-C, and hyperglycemia, but not hypertension. CONCLUSION: FFA was associated with MS and four of the five components of MS, i.e. central obesity, hypertriglyceridemia, hypertension, and hyperglycemia. It is suggested that FFA be one of the underlying pathogenic factors or risk factors for MS. FFA and insulin resistance may lead to MS through different but synergistic mechanisms.

Adult↗
PubMed2005

[Association of genetic polymorphism of XRCC1 with susceptibility to acute childhood leukemia].

OBJECTIVE: To explore the association between genetic polymorphisms of XRCC1 and susceptibility to acute childhood leukemia. METHODS: A case-control study with 63 childhood leukemia patients and 66 control subjects was conducted to investigate the role of three XRCC1 polymorphisms (c. 194, c. 280 and c. 399 ) on susceptibility to childhood leukemia. Genotyping was performed using Polymerase chain reaction-restrained fragment length polymorphism technique (PCR-RFLP) to detect the single nucleotide polymorphisms (SNPs) of XRCC1 gene. RESULTS: There was a 2.235-fold increased risk of childhood leukemia for individuals carrying XRCC1c. 399 Gin allele (95% CI 1.038 - 4.812) compared with subjects carrying Arg/Arg allele, and the OR among boys was 3.110 (95% CI 1.235 - 7.831). No interaction was found between X-ray exposure and XRCC1 polymorphisms using Logistic regression analysis. CONCLUSION: Polymorphism of XRCC1 gene may contribute to the higher risk of childhood leukemia.

Acute Disease↗
PubMed2005

[Metabolism of 125I labeled anti-p185 antibodies in vitro and their biodistribution in vivo].

AIM: To study the cellular metabolism(RIA) in vitro and the biodistribution in vivo of (125)I labeled anti-p185 antibodies(murine mAb A21, mouse-human chimeric antibody A21scFv-Fc and single chain antibody A21 scFv), to provide the basis for clinical application in the diagnosis and treatment of tumor overexpressing p185. METHODS: The specificity of binding of these antibodies to SKOV(3) known to highly express surface antigen p185 was assessd by FACS. The metabolism of the antibodies in SKOV(3) was assayed by cellular RIA. The biodistribution of radiolabeled antibodies was evaluated in nude mice bearing SKOV(3) tumor. RESULTS: Cellular RIA demonstrated these antibodies were internalized after binding to cells, followed by degradation and deiodination in cells, (125)I was then exocytosed. In vivo test showed that these antibodies were concentrated in tumor, but no concentration of control antibody in tumor was found. CONCLUSION: mAb A21, A21 scFv-Fc and A21 scFv can target human ovarian carcinoma cells (SKOV(3)) overexpressing p185 in vitro and in vivo and may be used in the diagnosis and treatment of tumors overexpressing p185.

Animals↗