Biomedical subjects

Lin Li

Publications and source records attributed to Lin Li.

At least 91 records · Page 5Linked to original sources

PubMed2006

Anticoagulant property of a semi-synthesized sodium beta-1,4-glucan sulfate.

AIM: To investigate the anticoagulant efficacy and mechanism of a semi-synthesized sodium beta-1,4-glucan sulfate (Na-MCS). METHODS: Anticoagulant activity was evaluated by means of coagulation assays in comparison with heparin. The anticoagulant mechanism of Na-MCS was disclosed by inhibitory analysis of the activities of coagulation factors using chromogenic substrates. RESULTS: 0.6 microg x mL(-1) Na-MCS could significantly prolong APTT and TT, but has less effect on PT at an even higher concentration. The dosage of Na-MCS required to double APTT of normal human plasma was 0.7 microg x mL(-1), lower than that of heparin with the activity of 150 u x mg(-1). CONCLUSION: Na-MCS represented a potent anticoagulation activity in vitro, which matched the efficacy of heparin in a certain range of concentrations. Na-MCS exhibited anticoagulant activity due to inhibition of the coagulation factors IIa and Xa by the mediation of anti-thrombin AT-III.

Anticoagulants↗

PubMed2006

[Construction and utilization of the prognostic model of serous ovarian adenocarcinoma].

OBJECTIVE: To analyze the related factors with prognosis in patients with serous ovarian adenocarcinoma and to set up a prognostic model of serous ovarian adenocarcinoma. METHODS: The clinical, pathological and follow-up data of 104 cases with serous ovarian adenocarcinoma were retrospectively analyzed. Kaplan-meier univariate analysis was used to screen the prognostic factors; COX univariate and multivariate analyses were used to determine the risk coefficient of each factors and different layers in each factor. Pearson rank correlation was used to reject the influence of different factors with each other. And the prognostic model of serous ovarian adenocarcinoma was set up based on the result of the above study, which could be used to deduce the survival probability of patients with serous ovarian adenocarcinoma. RESULTS: International Federation of Gynecology and Obstetrics (FIGO) stage (P = 0.0029), histological grade (P = 0.0054), residual disease (P = 0.0000), metastasis of lymph nodes (P = 0.0000) and chemotherapy (P = 0.0000) were the related factors of prognosis in patients with serous ovarian adenocarcinoma, of which FIGO stage was the most important one, followed sequentially by histological grade, metastasis of lymph node, residual disease and chemotherapy (the independent risk coefficient of each factor was 1.3392, 0.9206, 0.7071, 0.6004, 0.4985 in sequence). We set up a prognosis model according to the prognostic index of each factors. The effect of chemotherapy and residual disease on prognosis could be quantified by this model, and the higher the score, the lower the survival probability of patients. CONCLUSIONS: FIGO stage, histological grade, residual disease, metastasis of lymph nodes and chemotherapy are important prognostic factors of serous ovarian adenocarcinoma. This model can be used to estimate the prognosis of patients with serous ovarian adenocarcinoma, and the effect of both chemotherapy and residual disease on the prognosis could be quantified by the model.

Adult↗

PubMed2006

Is the hypoxia-inducible factor-1 alpha mRNA expression activated by ethanol-induced injury, the mechanism underlying alcoholic liver disease?

BACKGROUND: Excessive alcohol consumption can result in multiple organ injury, of which alcoholic liver disease (ALD) is the most common. With economic development and improvement of living standards, the incidence of diseases caused by alcohol abuse has been increasing in China, although its pathogenesis remains obscure. The aim of this study was to investigate the role of hypoxia in chronic ALD. METHODS: Twenty-eight male Sprague-Dawley rats were randomized into a control group (n=12) with a normal history and an experimental group (n=16) fed with 10 ml/kg of 56% (vol/vol) ethanol once per day by gastric lavage for 24 weeks. At 24 weeks, blood samples were collected and then the rats were killed. Liver samples were frozen at -80 degrees C and used for RT-PCR; other liver samples were obtained for immunohistochemical staining. RESULTS: When the period of alcohol consumption increased, the positive rate of expression of hypoxia-inducible factor-1 alpha (HIF-1alpha) mRNA was more significantly elevated in the liver of the alcohol group than in the control group (P < or = 0.05). The HIF-1alpha protein located in the cytoplasm was seldom expressed in the control group, but significantly in the alcohol group (P < or = 0.01). CONCLUSION: HIF-1alpha mRNA expression was activated by ethanol-induced injury in this study, suggesting that hypoxia is involved in the underlying mechanism of ALD.

Animals↗

PubMed2006

[Modern biological basis of Chinese medical theory that "kidney nourishes marrow and brain is sea of marrow"].

The theory that "the kidney nourishes marrow and brain is the sea of marrow" has been instructing traditional Chinese medical doctors in preventing and treating dementia in aged people for thousands of years. However, the modern biological basis of this theory has not been systemically studied. In this review, we summarized our serial pharmacological studies on the treatment of Alzheimer's disease (AD) with Chinese medicinal herbs, using multiple kinds of AD-like animal and cell models. The results show that "kidney-reinforcing" herbs of traditional Chinese medicine play a very important role in the anti-AD effects; and different "kidney-reinforcing" herbs have different effects in brain functions. The common effects of "kidney-reinforcing" herbs are improving cellular energy metabolism, increasing neurotrophic factors and the number of cholinergic neurons, and decreasing neurotoxin production. Based on above results, we propose that the essence of "brain marrow" is the neurons and neurotrophic factors in the brain; "the deficiency of brain marrow" is induced by the decrease in neurotrophic factors and the atrophy and loss of neurons in the brain, thus resulting in cognitive impairment and dementia. The modern biological basis of "reinforcing kidney to replenish marrow" by traditional Chinese medicine includes improving cellular energy metabolism and utilization, enhancing endogenous neurotrophic effects and decreasing neurotoxin production, thus reducing the cell death and increasing the survival and regeneration of neurons.

Alzheimer Disease↗

PubMed2006

Polyclonal plasma cell proliferation with marked hypergammaglobulinemia and multiple autoantibodies.

A 77-yr-old man presented with marked peripheral blood and bone marrow plasmacytosis, marked hypergammaglobulinemia, and multiple autoantibodies. Serum protein immunofixation and immunophenotyping of bone marrow plasma cells by flow cytometry and immunohistochemistry disclosed polyclonal proliferation of plasma cells at various stages of differentiation. The presence of multiple autoantibodies in the patient's serum suggests that an autoimmune disease underlies the polyclonal proliferation of plasma cells.

Aged↗

PubMed2006

Mechanism of neurophysiological treatment of amblyopia using functional magnetic resonance imaging.

PURPOSE: To research the mechanism of neurophysiological treatment of amblyopia by observing the visual cortex activation under rotating grating stimulus with functional magnetic resonance imaging (MRI), and identify the components of the activation. METHODS: Nine healthy volunteers were examined using gradient-recalled echo and echo-planar imaging (GRE-EPI) pulse sequence performed at the 1.5 Tesla MRI scanner. In the block designing, rotating grating, stationary grating and luminance were plotted as task states, stationary grating, luminance and darkness as control states, respectively. The tasks of stimuli included 6 steps. Imaging processing and statistical analysis were carried out off-line using statistical parametric mapping (SPM99) software in single-subject. RESULTS: Some individual areas of visual cortex were activated by various stimuli information supplied by rotating grating. The strong activation in the middle of occipital lobe related to the stimuli of luminance, bilateral activation of Brodmann's 19th area related to visual motion perception, and the mild activation in the middle of occipital lobe related to form perception. CONCLUSION: The plotting of control state is important in bock design. The effective visual information of rotating grating includes components of luminance, visual motion perception and form perception. Functional MRI has potential as a tool for studying the physiological mechanism of visual cortex.

Adult↗

PubMed2006

[A cross-sectional survey of blindness and low vision among adults aged 60 years and above in Xinchengqiao Blocks, Nantong].

OBJECTIVE: To investigate the prevalence and causes of blindness and low vision among adults aged > or = 60 years in the urban population of Nantong. METHODS: Cluster sampling was used to select 8 from 14 communities in Xinchengqiao Blocks, in which all individuals aged > or = 60 years were visited. The visual acuity without correction and the presenting acuity with the participants' habitual distance correction were measured separately for each eye. In individuals with visual acuity less than 0.6, pinhole visual acuity was tested with pinhole spectacle. External eye, anterior segment and ocular fundus were examined by the ophthalmologist using a slit lamp-microscope and direct ophthalmoscopy. The survey was preceded by a pilot study. RESULTS: Of 3352 enumerated subjects, 3040 individuals participated in this survey (90.69% response rate). According to pinhole visual acuity and World Health Organization (WHO) visual impairment criterion (blindness: less than 0.05 in the better eye; low vision: less than 0.3 to 0.05 in the better eye), the prevalence of blindness and low vision was 1.35% and 1.84% respectively. The prevalence of blindness and low vision for females were 1.92% and 2.33%, respectively, which were differenced from that in males (0.66% and 1.24%, respectively). The prevalence of blindness and low vision increased with age. The survey showed that the most important cause leading to blindness and low vision was cataract. According to the presenting visual acuity and visual impairment criterion (blindness: less than 0.1 in both eyes), the prevalence of blindness and visual impairment was 1.58% and 13.59%, respectively, 2.10% and 15.98% in females and 0.95% and 10.66% in males, respectively. The prevalence of blindness and visual impairment was raised with increasing age. Cataract was also the leading cause for blindness. CONCLUSIONS: The prevalence of blindness in the Nantong area was lower than that in northern, southern and western China. Females and illiteracy were more likely to have blindness and low vision than that of males and literate. The leading causes of blindness in Nantong are, in descending sequence, cataract, ocular fundus diseases, ametropia and corneal scar/opacity.

Aged↗

PubMed2005

Modeling porosity reductions caused by mineral fouling in continuous-wall permeable reactive barriers.

A study was conducted to assess key factors to include when modeling porosity reductions caused by mineral fouling in permeable reactive barriers (PRBs) containing granular zero valent iron. The public domain codes MODFLOW and RT3D were used and a geochemical algorithm was developed for RT3D to simulate geochemical reactions occurring in PRBs. Results of simulations conducted with the model show that the largest porosity reductions occur between the entrance and mid-plane of the PRB as a result of precipitation of carbonate minerals and that smaller porosity reductions occur between the mid-plane and exit face due to precipitation of ferrous hydroxide. These findings are consistent with field and laboratory observations, as well as modeling predictions made by others. Parametric studies were conducted to identify the most important variables to include in a model evaluating porosity reduction. These studies showed that three minerals (CaCO3, FeCO3, and Fe(OH)2 (am)) account for more than 99% of the porosity reductions that were predicted. The porosity reduction is sensitive to influent concentrations of HCO3-, Ca2+, CO3(2-), and dissolved oxygen, the anaerobic iron corrosion rate, and the rates of CaCO3 and FeCO3 formation. The predictions also show that porosity reductions in PRBs can be spatially variable and mineral forming ions penetrate deeper into the PRB as a result of flow heterogeneities, which reflects the balance between the rate of mass transport and geochemical reaction rates. Level of aquifer heterogeneity and the contrast in hydraulic conductivity between the aquifer and PRB are the most important hydraulic variables affecting porosity reduction. Spatial continuity of aquifer hydraulic conductivity is less significant.

Chemical Precipitation↗

PubMed2005

Antibody microarray profiling reveals individual and combined serum proteins associated with pancreatic cancer.

We used antibody microarrays to probe the associations of multiple serum proteins with pancreatic cancer and to explore the use of combined measurements for sample classification. Serum samples from pancreatic cancer patients (n = 61), patients with benign pancreatic disease (n = 31), and healthy control subjects (n = 50) were probed in replicate experiment sets by two-color, rolling circle amplification on microarrays containing 92 antibodies and control proteins. The antibodies that had reproducibly different binding levels between the patient classes revealed different types of alterations, reflecting inflammation (high C-reactive protein, alpha-1-antitrypsin, and serum amyloid A), immune response (high IgA), leakage of cell breakdown products (low plasma gelsolin), and possibly altered vitamin K usage or glucose regulation (high protein-induced vitamin K antagonist-II). The accuracy of the most significant antibody microarray measurements was confirmed through immunoblot and antigen dilution experiments. A logistic-regression algorithm distinguished the cancer samples from the healthy control samples with a 90% and 93% sensitivity and a 90% and 94% specificity in duplicate experiment sets. The cancer samples were distinguished from the benign disease samples with a 95% and 92% sensitivity and an 88% and 74% specificity in duplicate experiment sets. The classification accuracies were significantly improved over those achieved using individual antibodies. This study furthered the development of antibody microarrays for molecular profiling, provided insights into the nature of serum-protein alterations in pancreatic cancer patients, and showed the potential of combined measurements to improve sample classification accuracy.

Adenocarcinoma↗

PubMed2005

Molecular cloning and mRNA expression of duck invariant chain.

In the present study we identified a duck invariant chain (Ii) cDNA, named duck Ii-1, by RT-PCR and RACE. It was 1190 bp in length and contained a 669 bp open reading frame. An alternative transcript encoding a thyroglobulin (Tg)-containing form of Ii, named duck Ii-2, was also found in duck. The putative amino acid sequence of duck Ii-1 showed an 82% similarity to chicken Ii-1 and about 60% similarity to its mammalian homologues. The similarity of the Tg domain between duck and chicken Ii-2 was 96%, and about 70% between duck and mammalian Ii. The result of RT-PCR showed that Ii mRNA was extensively expressed in various tissues. High levels of both Ii-1 and Ii-2 mRNA were observed in the spleen and bursa of Fabricius. The predicted three-dimensional (3D) structures of duck Ii trimerization and Tg domain are similar to the corresponding regions of human Ii analyzed by comparative protein modeling. These findings indicate that the two isoforms of duck Ii, which strongly expressed in the major immune organs, share structural identity with human Ii.

Amino Acid Sequence↗

PubMed2005

Beta-catenin regulates myogenesis by relieving I-mfa-mediated suppression of myogenic regulatory factors in P19 cells.

Wnt/beta-catenin signaling plays a critical role in embryonic myogenesis. Here we show that, in P19 embryonic carcinoma stem cells, Wnt/beta-catenin signaling initiates the myogenic process depends on beta-catenin-mediated relief of I-mfa (inhibitor of MyoD Family a) suppression of myogenic regulatory factors (MRFs). We found that beta-catenin interacted with I-mfa and that the interaction was enhanced by Wnt3a. In addition, we found that the interaction between beta-catenin and I-mfa was able to attenuate the interaction of I-mfa with MRFs, relieve I-mfa-mediated suppression of the transcriptional activity and cytosolic sequestration of MRFs, and initiate myogenesis in a P19 myogenic model system that expresses exogenous myogenin. This work reveals a mechanism for the regulation of MRFs during myogenesis by elucidating a beta-catenin-mediated, but lymphoid enhancing factor-1/T cell factor independent, mechanism in regulation of myogenic fate specification and differentiation of P19 mouse stem cells.

Animals↗

PubMed2005

Effects of a PPO-PEO-PPO triblock copolymer on micellization and gelation of a PEO-PPO-PEO triblock copolymer in aqueous solution.

The effects of a PPO-PEO-PPO triblock copolymer (25R4, PO(19)-EO(33)-PO(19)) on thermoreversible micellization and gelation properties of a PEO-PPO-PEO triblock copolymer (F108, EO(133)-PO(50)-EO(133)) in water were studied by means of micro-DSC and rheology. A complete, mirror-image like thermoreversible behavior has been observed for all of the samples with various molar ratios of 25R4 to F108. At a given concentration of F108, the addition of 25R4 results in the salt-out like effect on the primary micellization of F108; that is, the critical micellization temperature (CMT) of F108 shifts to lower temperatures with increasing the content of 25R4. The enthalpy changes for micellization are a linear function of the 25R4/F108 molar ratio at a fixed F108 concentration. Beyond the primary peak for the micellization of F108, a secondary peak or shoulder is observed in the DSC curves for the samples with the higher 25R4/F108 molar ratios, due to the formation of the hydrophobic aggregates from both the PPO blocks of F108 and those (i.e., PPO blocks) of 25R4. Furthermore, as an example, the dynamic viscoelastic properties of 18 wt % F108 solutions with various contents of 25R4 have been examined. It is found that, when the 25R4/F108 molar ratio < or =1, 25R4 does not affect the gelation of F108 notably. When the ratio is greater than 1, however, the formation of the 25R4-bridged micellar aggregates delays the gelation of F108 significantly. A schematic model has been proposed to explain the mechanism for the 25R4-influenced micellization and gelation of F108.

Journal Article↗

PubMed2005

Morphology-driven surface segregation in a blend of poly(epsilon-caprolactone) and poly(vinyl chloride).

A blend of poly(epsilon-caprolactone) (PCL) and poly(vinyl chloride) (PVC) with 90 wt % PCL was prepared. Two films of this blend, which were grown at 35 and 45 degrees C, showed the absence and presence of banded spherulites, respectively. A detailed examination conducted with time-of-flight secondary ion mass spectrometry (ToF-SIMS) found that the surface composition of the film grown at 45 degrees C was related to its structure, which was shown to contain ridges and valleys. Phase images obtained using atomic force microscopy (AFM) indicated that the ridges and valleys consisted of edge-on and flat-on lamellae, respectively. ToF-SIMS imaging revealed that PVC and PCL were located mainly on the surface of the valleys and ridges, respectively. This morphology-driven surface segregation was caused by the difference in the surface energy between the flat-on and edge-on lamellae.

Microscopy, Atomic Force↗

PubMed2005

Unburned carbon as a low-cost adsorbent for treatment of methylene blue-containing wastewater.

Fly ash, natural zeolite, and unburned carbon separated from fly ash have been employed as low-cost adsorbents for dye adsorption in methylene blue-containing wastewater. It is found that the unburned carbon exhibits a much higher adsorption capacity than raw fly ash and natural zeolite. The adsorption capacities of fly ash, natural zeolite, and unburned carbon for methylene blue are 2 x 10(-5), 5 x 10(-5), and 2.5 x 10(-4) mol/g, respectively. Investigation also indicates that adsorption is influenced by initial dye concentration, particle size, dye solution pH, and adsorption temperature. Adsorption on unburned carbon increases with the initial dye concentration, solution pH, and temperature, but reduces with the increasing particle size. Kinetic studies show that adsorption of methylene blue on fly ash, natural zeolite, and unburned carbon can be best described by the pseudo-second-order adsorption model and that adsorption is a two-step diffusion process. The apparent activation energies for methylene blue adsorption on unburned carbon in the first and second diffusion processes are 12.4 and 39.3 kJ/mol, respectively.

Adsorption↗

PubMed2005

Release of theophylline from polymer blend hydrogels.

Polymer blending is a simple yet attractive method to obtain combined physical and mechanical properties of polymers. In this paper, three types of blend hydrogels were prepared, each by physically blending two different natural polymers, and a model drug, theophylline (TPH), was immobilized into these hydrogels for the studies of drug release. The release profiles of TPH from various types of hydrogels were determined by UV-vis absorption measurement at 272 nm. The experimental results show that the releases of TPH from these hydrogels are dependent upon the composition of the hydrogel, the type of component, the possible interactions between two component polymers, as well as external temperature. All the release profiles clearly demonstrate a temperature effect. Among the three blend hydrogels, the slowest release was observed from the blend hydrogel of gelatin and agar with a weight ratio of 1:1. The drug release patterns and release mechanisms have been discussed by considering the possible molecular interactions and gel network structures.

Carrageenan↗

PubMed2005

The aggregation behavior of O-carboxymethylchitosan in dilute aqueous solution.

O-Carboxymethylchitosan (OCMCS) is a kind of biocompatible derivatives of chitosan whose water solubility is strongly dependent on the degree of carboxymethylation. The OCMCS with 100 carboxymethyl groups and 75 amino groups per 100 anhydroglucosamine units of OCMCS was synthesized by the reaction of chitosan and monochloroacetic. When OCMCS was dissolved in water, its solution was neutral and OCMCS behaved like a weak polyanionic polyeclectrolyte because most of carboxylic groups were not dissociated in neutral aqueous solution. The aggregation behavior of OCMCS in aqueous solution was studied by surface tensiometry, steady-state fluorescence spectroscopy and viscometry. The critical aggregation concentration (cac) of OCMCS was determined to be between 0.042 mg/ml and 0.050 mg/ml. The possible aggregation mechanism of OCMCS in water was elucidated.

Biocompatible Materials↗

PubMed2005

Optimizing radiolabeled engineered anti-p185HER2 antibody fragments for in vivo imaging.

We have recently described the in vivo properties of an iodinated anti-p185HER2 engineered antibody fragment [minibody (scFv-C(H)3)2; 80 kDa], made from the internalizing 10H8 monoclonal antibody. Although the 10H8 minibody showed excellent binding to the target in vitro, only modest tumor uptake [5.6 +/- 1.7% injected dose per gram (ID/g) of tissue] was achieved in nude mice bearing MCF7/HER2 breast cancer tumors. Here, in an attempt to improve targeting, the 10H8 minibody was conjugated to 1,4,7,10-tetraazacyclododecane-N, N', N'', N'''-tetraacetic acid (DOTA), radiometal labeled, and evaluated in vivo. The tumor uptake of 111In-DOTA 10H8 minibody was 5.7 +/- 0.1% ID/g, similar to the radioiodinated 10H8 minibody. However, in addition to the expected liver clearance, the kidneys had unexpectedly high activity (34.0 +/- 4.0% ID/g). A minibody derived from a second anti-p185(HER2) antibody (trastuzumab; hu4D5v8) was also made. Tumor uptakes, evaluated by quantitative microPET using 64Cu-DOTA hu4D5v8 minibody, were 4.2 +/- 0.5% ID/g. Furthermore, in non-tumor-bearing mice, 111In-DOTA hu4D5v8 minibody exhibited similar elevated uptake in the kidneys (28.4 +/- 6.5% ID/g). Immunohistochemical staining of kidneys from non-tumor-bearing mice showed strong specific staining of the proximal tubules, and Western blot analysis of kidney lysate confirmed the presence of cross-reactive antigen. To further improve tumor uptake and normal tissue distribution, a larger hu4D5v8 fragment [(scFv-C(H)2-C(H)3)2; 105 kDa] was made, engineered to exhibit rapid clearance kinetics. This fragment, when evaluated by microPET, exhibited improved tumor targeting (12.2 +/- 2.4% ID/g) and reduced kidney uptake (13.1 +/- 1.5% ID/g). Thus, by manipulating the size and format of anti-p185(HER2) antibody fragments, the kidney activity was reduced and high or low expression of p185HER2 in xenografts could be distinguished by microPET imaging.

Animals↗

PubMed2005

Differential intranuclear organization of transcription factors Sp1 and Sp3.

Sp1 and Sp3 are ubiquitously expressed mammalian transcription factors that activate or repress the expression of a variety of genes and are thought to compete for the same DNA binding site. We used indirect immunofluorescence microscopy and image deconvolution to show that Sp1 and Sp3 are organized into distinct nonoverlapping domains in human breast and ovarian cells. Domains of Sp1 and Sp3 infrequently associate with sites of transcription. Sp3 partitions with the tightly bound nuclear protein fraction of hormone responsive MCF-7 breast cancer cells, whereas only a subpopulation of Sp1 is found in that fraction. Both Sp1 and Sp3 are bound to the nuclear matrix, and the nuclear matrix-associated sites of Sp1 and Sp3 are different. Indirect immunofluorescence studies demonstrate that Sp1 and Sp3 associate with histone deacetylases 1 and 2 and with the estrogen receptor alpha, albeit at low frequencies in MCF-7 cells. Chromatin immunoprecipitation (ChIP) and re-ChIP assays revealed that although both Sp1 and Sp3 bind to the estrogen-responsive trefoil factor 1 promoter in MCF-7 cells, they do not occupy the same promoter. Our results demonstrate the different features of Sp1 and Sp3, providing further evidence that Sp3 is not a functional equivalent of Sp1.

Cell Line, Tumor↗