Biomedical subjects

Li Li

Publications and source records attributed to Li Li.

At least 199 records · Page 11Linked to original sources

PubMed2006

[Evaluation of oxidative stress in experimental rabbit aneurysms].

OBJECTIVE: To evaluate the roles of oxidative stress in the generation and development of aneurysms. METHODS: Five terminal aneurysms and 8 lateral aneurysms were rebuilt on rabbits, and 6 normal artery vessels were prepared as control. The levels of malondialdehyde (MDA), superoxide dismutase (SOD), and anti-reactive oxygen species unit (anti-ROS unit) were measured with chemical methods. RESULTS: The levels of MDA in terminal and lateral aneurysms were (33.85 +/- 8.66) and (27.87 +/- 5.78) nmol/mg prot, respectively, which were significantly higher than (10.91 +/- 2.72) nmol/mg prot in control group (P < 0.01). The levels of SOD in terminal and lateral aneurysms were (28.30 +/- 3.58) and (33.00 +/- 8.09) U/mg prot, respectively, which were significantly lower than (127.27 +/- 38.72) U/mg prot in control group (P < 0.01). The levels of anti-ROS unit in terminal and lateral aneurysms were (47.86 +/- 5.00) and (62.64 +/- 13.87) U/ mg prot, respectively, which were significantly lower than (116.94 +/- 9.22) U/mg prot in control group (P < 0.01). No significant differences were shown between terminal aneurysm and lateral aneurysm in MDA and SOD except anti-ROS unit (P = 0.014). MDA had negative correlations with both SOD and anti-ROS unit, and the correlation coefficients were -0. 830 and -0. 852, respectively. CONCLUSION: Oxidative stress may play an important role in the development of aneurysms. Oxidative stress seems similar among various aneurysms.

Aneurysm↗

PubMed2006

[Patterns and prognostic value of resection margin involvement and lateral pelvic metastases for patients with rectal cancer].

OBJECTIVE: To study the patterns and prognostic value of resection margin involvement and lateral pelvic metastases, providing surgeons with pathologic proofs of tumor spread within the studied areas. METHODS: Large tissue slices of 62 specimens from patients with rectal cancer were used in the pathologic study and the outcomes were followed. RESULTS: Compared with patients without margin involvement, patients with circumferential margin involvement (CMI), seen in 8 cases (12.9%), had poorer postoperative survival (P=0.003). The 12 patients (19.4%) with lateral pelvic metastases suffered poorer survival, compared with those without lateral pelvic metastases (P=0.026). Eight patients (66.7%) were diagnosed to have single lateral pelvic region involved, while the other 4 had multiple regions involved. The incidence of lateral metastases differed among regions, with higher occurrence in the root of middle rectal artery (6/12, 50.0%), area of the internal iliac artery (4/12, 33.3%) and the obturator region (3/12, 25.0%). CONCLUSION: Occurrence of CMI or lateral metastases in rectal cancer patients predispose poor survival, thus a more radical clearance and postoperative adjuvant therapy are recommended.

Adult↗

PubMed2006

[Effect of vascular endothelial growth factor on apoptosis and expression of Bcl-2 and Mcl-1 in acute leukemia cells].

OBJECTIVE: To investigate the effect of vascular endothelial growth factor (VEGF) on the apoptosis of human acute leukemia HL-60 cell line and to analyze the role of the related apoptosis genes, such as Bcl-2 and Mcl-1, in the process of apoptosis of human acute leukemia cells. METHODS: HL-60 cells were treated with different concentrations of VEGF (2 microg/L, 20 microg/L or 100 microg/L ) or 20 mg/L of etoposide (VP16, an apoptosis inducter) alone or VEGF plus VP16. After 18 hrs of treatment, the apoptosis rate of HL-60 cells was detected by single-cell gel electrophoresis and flow cytometry. The expressions of Bcl-2 and Mcl-1 of HL-60 cells were detected by RT-PCR. The Control group did not receive any treatment. Immunocytochemistry was used to detect the VEGF and Mcl-1 protein in bone marrow cells from 8 patients with newly diagnosed or relapsed leukemia, 14 leukemia patients in complete remission, and from 5 normal children. RESULTS: Different concentrations of VEGF markedly inhibited the apoptosis of HL-60 cells and decreased the apoptosis induced by VP16 exposure. The Bcl-2 and Mcl-1 mRNA and protein in HL-60 cells treated with VEGF were significantly higher than those in the Control group. The expressions of VEGF and Mcl-1 protein in bone marrow cells of the newly diagnosed and relapsed patients were significantly higher than in patients in complete remission. CONCLUSION: VEGF can inhibit the apoptosis of HL-60 cells possibly through increasing the expressions of Bcl-2 and Mcl-1 mRNA and protein, which may represent one of the mechanisms responsible for human acute leukemia. The expressions of VEGF, Bcl-2 and Mcl-1 might be used as the markers for the prognostic evaluation of leukemia.

Apoptosis↗

PubMed2006

[Inhibitory effects of RNA interference on expression of matrix metalloproteinase-9 gene and invasiveness and adhesion in ovarian cancer cells].

OBJECTIVE: To investigate the inhibitory effects of RNA interference (RNAi) on the expression of matrix metalloproteinase-9 (MMP-9) gene and invasiveness and adhesion of ovarian cancer cells. METHODS: Four groups of different specific target sequence in coding region of MMP-9 and one non-specific sequence were chosen, which were Site1, Site2, Site3, Site4 and Site5. Small interference RNA (siRNA) expression cassettes (SEC) were constructed by PCR and transfected into ovarian cancer HO-8910PM cells. RT-PCR and western blot were used to detect mRNA and protein expression of MMP-9 gene; the abilities of invasion and adhesion were detected by Matrigel invasion assay and cell adhesion assay. RESULTS: The expression of MMP-9 was inhibited and the inhibitory effects of different sequence were varied. The mRNA expression was 0.64 +/- 0.06, 0.47 +/- 0.07, 0.55 +/- 0.10 in Site1, Site2, Site3 group, and protein expression was 0.30 +/- 0.09, 0.27 +/- 0.08, 0.37 +/- 0.12, respectively. Site2 group had the most efficient inhibitory effect, followed by Site1 and Site3 groups. Cell growth curve revealed that cell growth was significantly inhibited in Site2 group. Invasiveness and adhesion were significantly reduced, the inhibitory rate on invasion in Site1, Site2, Site3 groups were 50.0%, 50.0% and 37.5%, respectively; the inhibitory rate on adhesion in Site1, Site2, Site3, Site4 groups were 43.8%, 48.8%, 33.9%, 24.2% at 60 min and 41.6%, 40.2%, 35.1%, 16.0% at 90 min, respectively. CONCLUSIONS: RNAi exists in ovarian HO-8910PM cells. MMP-9 siRNA can specifically down-regulate MMP-9 expression and lead to the inhibition of invasiveness and adhesion in ovarian cancer cells.

Blotting, Western↗

PubMed2006

[Prenatal diagnosis and outcomes of fetuses with cutaneous hemangioma].

OBJECTIVE: To study the ultrasonic characteristics of fetal cutaneous hemangioma and the association with perinatal outcomes. METHODS: Five fetuses with cutaneous hemangioma were detected by gray-scale and color Doppler ultrasound, compared with the result of pathology and hematology examinations after birth. RESULTS: Of the 5 cases diagnosed by ultrasound, 3 had arteriovenous fistulas. In these 3 cases two fetuses developed high-output cardiac failure, and one developed cardiac insufficiency and thrombocytopenia. Finally one fetus was induced, one fetus died in the uterus and one neonate survived. The other two fetuses who had small tumors diagnosed by ultrasound did not develop any perinatal complications, and the neonates had favourable prognosis. CONCLUSIONS: Massive hemangiomas are frequently associated with life-threatening complications such as high-output heart failure, thrombocytopenia and disseminated intravascular coagulopathy (Kasabach-Merritt syndrome).

Adult↗

PubMed2006

[Anti-apoptosis effect of astragaloside on adriamycin induced rat's cardiotoxicity].

OBJECTIVE: To study the possible mechanism of anti-myocardial cell apoptosis of astragaloside induced by adriamycin (ADR). METHODS: Fifty SD rats were randomized into five groups: the normal control group,the model group, the astragaloside low dose (A-L) group, the astragaloside medium dose (A-M) group and the astragaloside high dose (A-H) group, 10 in each group. The normal control group was given normal saline by intraperitoneal injection, while the other four groups were given ADR by intraperitoneal injection once every other day for six times with the total dosage of 15 mg/kg. At the same time, different dosage of astragaloside was administrated by gavage to the three treated groups, and sodium carboxymethycellulose (SCMC) was given to the normal control and the model group. Myocardial cell apoptosis was examined by in situ end-labeled DNA (TUNEL), protein and mRNA expressions of bax, bcl-2 were detected respectively with immunohistochemistry assay and RT-PCR. RESULTS: Compared with those in the normal control, apoptosis index was significantly higher, the protein and mRNA expressions of bcl-2 were lower and those of bax were higher, in the model group, resulted in lower ratio of bcl-2/bax (P < 0.05 or P < 0.01). However, in the A-H group, apoptosis index decreased significantly, the expressions of bcl-2 were higher, those of bax were lower, and ratio of the bcl-2/bax increased (all P < 0.05). CONCLUSION: High dose of astragaloside could suppress the myocardial cell apoptosis induced by ADR with the possible mechanism related to regulating the expressions of bcl-2 and bax.

Animals↗

PubMed2006

Arsenic exposure in pregnancy: a population-based study in Matlab, Bangladesh.

This study assessed the exposure of pregnant women to arsenic in Matlab, Bangladesh, an area with highly-elevated concentrations of arsenic in tubewells, by measuring concentrations of arsenic in urine. In a defined administrative area, all new pregnancies were identified by urine test in gestational week 6-8, and women were asked to participate in the assessment of arsenic exposure. Urine for analysis of arsenic was collected immediately and in gestational week 30. In total, 3,426 pregnant women provided urine samples during January 2002-March 2003. There was a considerable variation in urinary concentrations of arsenic (total range 1-1,470 microg/L, adjusted to specific gravity 1.012 g/mL), with an overall median concentration of 80 microg/L (25th and 75th percentiles were 37 and 208 microg/L respectively). Similar concentrations were found in gestational week 30, indicating no trend of decreasing exposure, despite the initiation of mitigation activities in the area. Arsenic exposure was negatively associated with socioeconomic classes and achieved educational level. There were marked geographical variations in exposure. The results emphasize the urgent need for efficient mitigation activities and investigations of arsenic-related reproductive effects.

Adolescent↗

PubMed2006

[Detection of IgVH mutation status in patients with chronic lymphocytic leukemia by multiplex PCR].

IgVH mutation status is one of the most important independent prognostic factor of chronic lymphocytic leukemia (CLL). In order to evaluate IgVH mutation status in patients with CLL, IgVH mutation was detected by multiplex PCR in 9 CLL patients and purified PCR amplification products were directly sequenced, IgH somatic hypermutation and mutation site were analysed by IMGT/V-QUEST. The results showed that 5 patients had mutated IgVH, and IgVHs were IGHV3-11*03, IGHV3-9*01, IGHV3-23*01, IGHV4-59*01, IGHV4-34*02, respectively; whereas 4 others had unmutated IgVH, these IgVHs were IGHV3-53*01, IGHV3-23*03, IGHV3-33*05 and IGHV3-7*01. It is concluded that multiplex PCR is a rapid and easy method to detect IgVH mutation status, and it solves the limitations and pitfalls of routine PCR, and it is worth being extensively used both in clinic and scientific researches.

Adult↗

PubMed2006

[The clinicopathological endomyocardial biopsy analysis in cardiac transplant recipients due to end-stage heart failure].

OBJECTIVE: Endomyocardial biopsies from 42 (35 males and 7 females, aged 43.3 years) heart transplant recipients due to end-stage heart failure between June 2004 and January 2006 in our institute were obtained for pathological studies. METHODS: Sixteen patients underwent 1 endomyocardial biopsy (right ventricular septum) between 13 days to 5 months, 13 patients underwent second biopsy between 1.5 to 8 months and 10 patients underwent third biopsy between 3 to 8.5 months post transplantation. Specimen were stained by hematoxylin-eosin (HE) and Phosphotungstic Acid Hematoxylin (PTAH) and observed under light microscope and cardiac allograft rejection were evaluated according to the Revision of the 1990 working formulation for the standardization of nomenclature in the diagnosis of heart rejection in 2004. RESULTS: The rejection grades were as follows: Grade 0 R in 31 biopsies; Grade 1 R (mild rejection 1990 grade 1A, 1B and 2.) in 30 biopsies; Grade 2 R (moderate rejection, 1990 grade 3A) in 3 biopsies; Grade 1 R cellular rejection companies with humoral rejection in 1 biopsy. Cellular rejection with Quilty effect was found in 2 biopsies. Ischemic myocardial injury presented in 4 biopsies. Quilty effect was observed in 1 biopsy. Cytomegalovirus or toxoplasmic myocarditis was not observed. CONCLUSIONS: Endomyocardial biopsy (EMB) is a valuable diagnostic procedure for rejection surveillance in heart allograft recipients. The observed low rejection incidence and mild rejection from specimens of our heart recipients were comparable to the results of developed countries.

Adolescent↗

PubMed2005

Budding dynamics of multicomponent tubular vesicles.

Real-time budding dynamics of multicomponent, tubular lipid vesicles was investigated. By using a fluorescence microscope, three typical growth modes of the buds were observed, corresponding, respectively, to bud growth through coalescence between flat patches, a bud and a patch, as well as that of two buds. The spatial and temporal scales measured in the observation were used to estimate the bending rigidity of the membrane. In the late stage, the continuing coalescence between the buds resulted in large shape deformation of the vesicles, from tubular to spherical vesicles, and the number of the buds decayed with time as N approximately t-2/3. This scaling relation was observed for the first time in experiment and confirmed early theoretical predictions. Our observation showed a difference between the diffusivity of the buds on the lipid membrane and that of the embedded membrane proteins.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed2005

An indirect enzyme-linked immunosorbent assay for rapid and quantitative assessment of Type III virulence phenotypes of Pseudomonas aeruginosa isolates.

BACKGROUND: The presence of a Type III secretion system in clinical isolates of Pseudomonas aeruginosa is associated with severe disease and poor outcomes in infections caused by this pathogen. We describe an indirect enzyme-linked immunosorbent assay that rapidly and quantitatively detects two exotoxins, ExoU and ExoT, and two structural components, PopD and PcrV, of the P. aeruginosa Type III secretion system after in-vitro growth in a calcium-free minimal medium. METHODS: We used this assay to characterize the Type III secretion phenotype of 74 clinical isolates of P. aeruginosa. Findings were compared with results of standard immunoblotting and correlated with Type III secretion-dependent virulence of isolates toward cultured epithelial cells. RESULTS: Results of the ELISA assay were concordant with immunoblot detection of the secreted antigens for 73 of 74 isolates. The Type III secretion phenotype assessed by this immunoassay predicted bacterial virulence toward epithelial cells in vitro for all but five of the clinical isolates. CONCLUSION: The availability of an ELISA assay for rapid detection of Type III secreted virulence factors will facilitate large clinical studies to examine whether the Type III secretion phenotype of a P. aeruginosa isolate predicts the course of clinical disease in a patient and should be taken into account in determining optimal treatment strategies for infected patients.

Antibodies, Monoclonal↗

PubMed2005

Pigment epithelium-derived factor gene therapy inhibits human pancreatic cancer in mice.

PURPOSE: Pigment epithelium-derived factor (PEDF), which has recently been shown to be the most potent inhibitor of angiogenesis in the mammalian eye, is also expressed in the pancreas. Previously, we have screened the expression of PEDF by immunohistochemical analysis and showed that low expression of PEDF is associated with increased risk of hepatic metastasis and short survival. The purpose of this study was to investigate whether PEDF gene is a potent tumor suppressor and a potential candidate for cancer gene therapy. EXPERIMENTAL DESIGN: We investigated both in vitro and in vivo growth characteristics of human pancreatic adenocarcinoma cell lines that were stably transfected to overexpress human PEDF and therapeutic effects of lentivirus-based vectors expressing PEDF on tumor growth in murine s.c. tumor model. RESULTS: We discovered that cells secreted PEDF protein in the media and this exhibited strong inhibitory effects on proliferation and migration of human umbilical vein endothelial cells. The size of PEDF-overexpressing pancreatic adenocarcinoma tumors was significantly smaller than that of control tumors in s.c. tumor models. Moreover, the growth of PEDF-overexpressing pancreatic adenocarcinoma cells was significantly suppressed in comparison with control cells in peritoneal metastasis models. In gene transfer models, intratumoral injection of a lentivirus vector encoding PEDF (LV-PEDF) caused significant inhibition of tumor growth. The antitumor effect observed after treatment with LV-PEDF was associated with decreased microvessel density in tumors. CONCLUSION: Our data suggest that PEDF may exert a biological effect on tumor angiogenesis and PEDF gene therapy may provide a new approach for treatment of pancreatic adenocarcinoma.

Adenocarcinoma↗

PubMed2005

Age-related changes in skin topography and microcirculation.

Skin topography and microvasculature undergo characteristic changes with age. Although several non-invasive bioengineering methods are currently available to measure them quantitatively, few publications have referred to their relationship with age in different anatomical sites. This study was carried out to observe the age-related changes of the skin topography and skin microcirculation. The microrelief was assessed with special processing software from scanning by interference fringe profilometry of silicone replicas performed on two sites (volar forearm and back of hand) on 50 female volunteers (aged 20-74 years who consisted of ten probands in each decade). The superficial vascular network of both sites was assessed by videocapillaroscopy, and the subpapillary vascular plexus was studied with laser Doppler flowmetry. Skin color, which is affected by blood flow, was observed by colorimeter. The skin roughness and the mean height between peak and valley increased with age. There were statistically significant differences between the evaluated sites. This study also shows that the capillary loops in the dermal papillae decrease but the subpapillary plexus increase with age. The interference fringe profilometry associated with videocapillaroscopy may be useful and accurate to measure the efficacy of medical or cosmetic products to delay skin aging.

Adult↗

PubMed2005

Coal ash conversion into effective adsorbents for removal of heavy metals and dyes from wastewater.

Fly ash was modified by hydrothermal treatment using NaOH solutions under various conditions for zeolite synthesis. The XRD patterns are presented. The results indicated that the samples obtained after treatment are much different. The XRD profiles revealed a number of new reflexes, suggesting a phase transformation probably occurred. Both heat treatment and chemical treatment increased the surface area and pore volume. It was found that zeolite P would be formed at the conditions of higher NaOH concentration and temperature. The treated fly ash was tested for adsorption of heavy metal ions and dyes in aqueous solution. It was shown that fly ash and the modified forms could effectively absorb heavy metals and methylene blue but not effectively adsorb rhodamine B. Modifying fly ash with NaOH solution would significantly enhance the adsorption capacity depending on the treatment temperature, time, and base concentration. The adsorption capacity of methylene blue would increases with pH of the dye solution and the sorption capacity of FA-NaOH could reach 5 x 10(-5) mol/g. The adsorption isotherm could be described by the Langmuir and Freundlich isotherm equations. Removal of copper and nickel ions could also be achieved on those treated fly ash. The removal efficiency for copper and nickel ions could be from 30% to 90% depending on the initial concentrations. The increase in adsorption temperature will enhance the adsorption efficiency for both heavy metals. The pseudo second-order kinetics would be better for fitting the dynamic adsorption of Cu and Ni ions.

Adsorption↗

PubMed2005

Effective interaction of charged platelets in aqueous solution: investigations of colloid laponite suspensions by static light scattering and small-angle x-ray scattering.

We study dilute aqueous solutions of charged disklike mineral particles (laponite) by a combination of static light scattering (SLS) and small-angle x-ray scattering (SAXS). Laponite solutions are known to form gels above a certain critical concentration that must be described as nonequilibrium states. Here we focus on the investigation by SLS and SAXS at concentrations below gelation (c<0.016 g/L) and at low concentrations of added salt (0.001M and 0.005M). Thus, we have obtained the scattering function of single Laponite platelets as well as the structure factor describing their interaction at finite concentration. A detailed analysis of the combined sets of data proves that the solutions are in a well-defined equilibrium state. Moreover, this analysis demonstrates the internal consistency and accuracy of the scattering functions obtained at finite concentrations. We find that laponite particles interact through an effective pair potential that is attractive on short range but repulsive on longer range. This finding demonstrates that Laponite solutions exhibit only a limited stability at the concentration of added salt used herein. Raising the ionic strength to 0.005M already leads to slow flocculation as is evidenced from the enhanced scattering intensity at smallest scattering angles. All data strongly suggest that the gelation occurring at higher concentration is related to aggregation.

Journal Article↗

PubMed2005

Self-catalytic behavior of carbon nanotubes.

Self-catalytic behavior of multi-walled carbon nanotubes is proposed and validated experimentally under the conditions in which metal catalysis was previously figured to work only. The self-catalysis could support the nanotube nucleation and radial and axial developing processes. This result should lead to a new and better understanding of the growth mechanism of carbon nanotubes in a metal catalytic process.

Journal Article↗

PubMed2005

Connexin 26 variants and auditory neuropathy/dys-synchrony among children in schools for the deaf.

Genetic and auditory studies of 731 children with severe-to-profound hearing loss in US schools for the deaf and 46 additional children receiving clinical services for hearing loss ranging from moderate to profound demonstrated that mutations in the connexin 26 (GJB2) and connexin 30 (GJB6) genes explain at least 12% of those with nonsyndromic sensorineural deafness. Otoacoustic emissions (OAEs) testing to detect functional outer hair cells indicated that 76 of the children had emissions and therefore may have (as yet unconfirmed) auditory neuropathy/dys-synchrony (AN/AD). Five of these children with OAEs were GJB2 homozygotes or compound heterozygotes with the genotypes 35delG/35delG, W77X/W77X, 35delG/360delGAG, 35delG/V95M, and V84M/M34T. In particular, unilateral AN/AD was confirmed in a child with moderate hearing loss and the 35delG/V95M genotype. Detecting OAEs in individuals with GJB2 mutations suggests that lack of functional gap junctions as a result of GJB2 mutations does not necessarily destroy all outer hair cell function.

Adolescent↗

PubMed2005

Homocysteine from endothelial cells promotes LDL nitration and scavenger receptor uptake.

We recently reported that methionine-loaded human umbilical vein endothelial cells (HUVECs) exported homocysteine (Hcy) and were associated with hydroxyl radical generation and oxidation of lipids in LDL. Herein we have analysed the Hcy-induced posttranslational modifications (PTMs) of LDL protein. PTMs have been characterised using electrophoretic mobility shift, protein carbonyl ELISA, HPLC with electrochemical detection and Western blotting of 3-nitrotyrosine, and LDL uptake by scavenger receptors on monocyte/macrophages. We have also analysed PTMs in LDL isolated from rheumatoid (RA) and osteo-(OA) arthritis patients with cardiovascular disease (CVD). While reagent Hcy (< 50 microM) promoted copper-catalysed LDL protein oxidation, Hcy released from methionine-loaded HUVECs promoted LDL protein nitration. In addition, LDL nitration was associated with enhanced monocyte/macrophage uptake when compared with LDL oxidation. LDL protein nitration and uptake by monocytes, but not carbonyl formation, was elevated in both RA and OA patients with CVD compared with disease-matched patients that had no evidence of CVD. Moreover, a direct correlation between plasma total Hcy (tHcy) and LDL uptake was observed. The present studies suggest that elevated plasma tHcy may promote LDL nitration and increased scavenger receptor uptake, providing a molecular mechanism that may contribute to the clinical link between CVD and elevated plasma tHcy.

Adult↗