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Biomedical subjects

Xiao Li

Publications and source records attributed to Xiao Li.

At least 37 records · Page 2Linked to original sources

[Effects of temperature on the kinetics and level of energy charge and oxidation-reduction state in pyruvate biosynthesis].

Temperature plays an important role in pyruvate biosynthesis by Torulopsis glabrata 620. The effects of temperature on the substrate consumption, cell growth, pyruvate biosynthesis and level of energy charge and oxidation-reduction state have been investigated. During the constant temperature fermentation, higher temperature can enhance the rate of glucose consumption, cell growth and pyruvate production. However, it also leads to higher energy charge in the prophase of fermentation, too much consumption of glucose by cell and deficient throughput of pyruvate in the anaphase of fermentation, which brings on decrease of pyruvate yield. Oppositely, maintaining lower temperature during the fermentation can offer constant production capacity of pyruvate in the anaphase of fermentation. But the disadvantages are lower cell growth and higher level of NADH/NAD+ in vivo during the anaphase of fermentation, which leads to lower productivity inevitably. Disaccords above-mentioned indicate that the higher production, higher yield and higher productivity cannot be achieved at one time during a constant temperature fermentation.

Candida glabrata↗

[Tooth movement in tissue-engineered bone].

OBJECTIVE: To explore the effect and practical value of repairing the alveolar defects with tissue engineering technique and investigate the influence of the generated new bone on the orthodontic tooth movement. METHODS: The marrow stromal cells of rats were separated, cultured in vitro and induced to osteoblast-like cells. The osteoblast-like cells were implanted onto the ceramic bovine bone. Then the complex was implanted into the alveolar defect in one side of the rat's mandible. The other side of the mandible served as control. Eight weeks later, the orthodontic appliances were placed between the first molar and incisors of SD rats to move the first molar forward. The tooth movement and root resorption of the molar were observed. RESULTS: We found that the tooth movement in the experimental area was faster than that in the normal alveolar bone (P < 0.05). The root resorption and the alveolar bone height loss were less than that in the control area (P < 0.05). CONCLUSIONS: The tissue-engineered bone did not have negative influences on tooth movement. The repair of alveolar bone defect by tissue engineering approach may be used in craniofacial surgery and orthodontics.

Animals↗

[Role of Wnt/beta-catenin signaling transduction pathway in rat hepatocarcinogenesis].

AIM: To investigate the role of Wnt/beta-catenin signaling transduction pathway in rat hepatocarcinogenesis. METHODS: The mRNAs of Wnt1, beta-catenin, APC, cyclin D1 and c-myc genes were amplified by using of semiquantitative reverse transcription polymerase chain reaction (RT-PCR) from normal rat livers, atypical hyperplasia livers and hepatoma tissues, respectively. Then the proteins expression of beta-catenin, APC and cyclin D1 was examined by immunohistochemical staining. RESULTS: In normal rat livers, the mRNAs of Wnt1, cyclin D1 and c-myc genes were not detected and only beta-catenin protein was observed to have low expression at cellular membrane. However, 14 weeks after cancer induction in atypical hyperplasia livers, beta-catenin protein and APC protein were accumulated in cytoplasm. Meanwhile, cyclin D1 protein was detected in cytoplasm and/or nucleus in some cells. 16 weeks after cancer induction in hepatoma tissues, the mRNAs and protein expression of beta-catenin, APC, cyclin D1 and c-myc genes were detected except Wnt1. CONCLUSION: The activation of Wnt/beta-catenin signaling transduction pathway might be one of the reasons for rat hepatocarcinogenesis.

Animals↗

Computational detection of microRNAs targeting transcription factor genes in Arabidopsis thaliana.

MicroRNAs, an abundant class of tiny non-coding RNAs, have emerged as negative regulators for translational repression or cleavage of target mRNAs by the manner of complementary base paring in plants and animals. Recent studies have demonstrated that many known microRNAs have a remarkable propensity to target genes involved in development, particularly those of transcription factor genes. Therefore, an overall detection of Arabidopsis thaliana microRNAs targeting transcription factor genes will enhance greatly our understanding of microRNA biological functions in plant development. By searching short complementary sequences between transcription factor open-reading frames and intergenic region sequences, and considering RNA secondary structures and the sequence conversation between the genomes of Arabidopsis and Oryza sativa, we detected 96 candidate Arabidopsis microRNAs. These candidate microRNAs were predicted to target 102 transcription factor genes that are classified as 28 transcription factor gene families, particularly those of DNA-binding transcription factor families, which imply that microRNAs might be involved in complex transcriptional regulatory networks for specifying individual cell types in plant development.

Arabidopsis↗

Electroreduction activity of hydrogen peroxide on Pt and Au electrodes.

Hydrogen peroxide electroreduction on both catalytically active Pt and inactive Au surfaces are studied by using both surface-enhanced Raman spectroscopy (SERS) and density functional theory (DFT) calculations. SERS measurements on Pt show the presence of Pt-OH at negative potentials, which suggests that hydroxide is formed as an intermediate during the electroreduction process. Additionally, the O-O stretch mode of H(2)O(2) is observed on Pt, which shifts to lower energy as potential is swept negatively, indicating that the O-O bond is elongated. For comparison, there is no variation in the energy of the same O-O mode on Au surfaces, and there is no observation of Au-OH. DFT calculations show that H(2)O(2) adsorption on Pt(110) results in the dissociation of O-O bond and the formation of Pt-OH bond. On Au, O-O bond elongation is calculated to occur only on the (110) face. However, the magnitude of the elongation is much smaller than that found on Pt(110).

Journal Article↗

Successful management of postoperative recurrence of hepatocellular carcinoma with p53 gene therapy combining transcatheter arterial chemoembolization.

Transcatheter arterial chemoembolization (TACE) has become the standard treatment for unresectable hepatocellular carcinoma (HCC). But this method has some shortages. p53 gene, which was found to be mutant in many human tumors, has been proved with broad-spectrum anti-tumor effects. We reported a 23-year-old patient with recurrent HCC after irregular hepatectomy. The p53 gene was applied to this patient. We injected percutaneously and infused transcatheterally p53 gene (Gendicine, Shenzhen Sibiono Bentech, China) into his recurrent nodules in liver respectively and 4 d later, the patient received TACE therapy. In the 2 mo follow-up, the patient was in good clinical condition with normal liver function and no recurrence was identified. The case report proposed that recurrent HCC could be successfully treated with p53 gene therapy combining TACE.

Adult↗

Fabrication of non-close-packed arrays of colloidal spheres by soft lithography.

Ordered 2D non-close-packed sphere arrays with controllable lattice structures have been fabricated by using soft lithography based on the solvent-swelling and mechanical deformation behaviors of PDMS film. The figure shows an SEM image of the ordered quasi-one-dimensional parallel wires of silica spheres on a polymer-coated substrate.

Journal Article↗

Polyvinyl alcohol and gelatin sponge particle embolization of splenic artery pseudoaneurysm complicating chronic alcoholic pancreatitis.

AIM: To assess the effectiveness of and complications associated with polyvinyl alcohol (PVA) and gelatin sponge particles embolization of splenic artery pseudoaneurysm complicating chronic alcoholic pancreatitis. METHODS: A 42-year-old man with splenic artery pseudo-aneurysm formation secondary to chronic alcoholic pancreatitis was admitted. We used PVA and gelatin sponge particles embolization of splenic artery pseudoaneurysm by superselective embolization techniques. RESULTS: The splenic artery pseudoaneurysm was successfully controlled with splenic embolization. The patient was discharged in 9 d with complete recovery. CONCLUSION: This case confirms that superselective transcatheter embolization by PVA and gelatin sponge particles may represent an effective treatment for pseudoaneurysm caused by chronic alcoholic pancreatitis in the absence of other therapeutic alternatives.

Adult↗

Oxygen electroreduction through a superoxide intermediate on bi-modified Au surfaces.

The mechanism of the electroreduction of oxygen on bare and Bi-submonolayer-modified Au(111) surfaces is examined using surface enhanced Raman scattering (SERS) measurements along with detailed density functional theory (DFT) calculations. The spectroscopy reveals the presence of superoxide-level species at potentials where oxygen is reduced. These species are not present in solutions absent either oxygen or Bi at these potentials. The spectroscopy also reveals the presence of Bi-OH species which are associated with peroxide reduction. Detailed calculations show oxygen associates much more strongly with Bi in the (2 x 2) configuration on Au(111) relative to the bare Au surface. Additionally, the O-O bond is elongated following O2 association, which follows as a consequence of Bi-O bond formation and partial oxidation of the Bi adatom. These results show for the first time that the four-electron electroreduction of oxygen electroreduction occurs via a series pathway on the Bi-modified surface in acid solution.

Journal Article↗

Alterations in morphine-induced reward, locomotor activity, and thermoregulation in CREB-deficient mice.

Previous studies in our lab have shown a robust decrease in the rewarding properties of morphine in CREB(alphaDelta) mutant mice. To determine whether the genetic effects of the global CREB(alphaDelta) mutation are specific to reward or generalizable, we examined a variety of morphine-induced behaviors regulated by different neural circuitry. At low doses of morphine (5 and 10 mg/kg), CREB(alphaDelta) mutant mice show a reduction in reward yet similar locomotor activity in response to morphine compared to wild type littermates. However, at a high dose (20 mg/kg), CREB(alphaDelta) mutant mice show an increase in reward and locomotor activity. Morphine-induced thermoregulation is attenuated in CREB(alphaDelta) mutant mice at high doses of morphine compared to wild type animals. The behavioral differences in response to morphine seen in CREB(alphaDelta) mutant mice are not due to changes in mu opioid receptor (MOR) mRNA expression, as the CREB deletion has no effect on baseline MOR mRNA in three of the brain regions involved in mediating these behaviors: the ventral tegmental area (VTA), nucleus accumbens (NAc), and hypothalamus. These data demonstrate that at low doses, deficits in morphine-induced changes in CREB deficient mice are limited to reward and thermoregulation. However, at higher doses, CREB mutant mice actually find morphine more rewarding and exhibit increased locomotor activity compared to their wild type littermates. Together, these results indicate that the role of CREB in dose-dependent changes in behaviors induced by morphine is different depending on the brain regions involved in mediating the behavior.

Analysis of Variance↗

Detection of hypervascular hepatocellular carcinoma: Comparison of multi-detector CT with digital subtraction angiography and Lipiodol CT.

AIM: The purpose of this study was to compare the diagnostic accuracy of biphasic multi-detector row helical computed tomography (MDCT), digital subtraction angiography (DSA) and Lipiodol computed tomography (CT) in detection of hypervascular hepatocellular carcinoma (HCC). METHODS: Twenty-eight patients with nodular HCC underwent biphasic MDCT examination: hepatic arterial phase (HAP) 25 s and portal venous phase (PVP) 70 s after injection of the contrast medium (1.5 mL/kg). They also underwent hepatic angiography and intra-arterial infusion of iodized oil. Lipiodol CT was performed 3-4 wk after infusion. MDCT images were compared with DSA and Lipiodol CT images for detection of hepatic nodules. RESULTS: The three imaging techniques had the same sensitivity in detecting nodules >20 mm in diameter. There was no significant difference in the sensitivity among HAP-MDCT, Lipiodol CT and DSA for nodules of 10-20 mm in diameter. For the nodules <10 mm in diameter, HAP-MDCT identified 47, Lipiodol CT detected 27 (chi2 = 11.3, P = 0.005<0.01, HAP-MDCT vs Lipiodol CT) and DSA detected 16 (chi2 = 9.09, P = 0.005<0.01 vs Lipiodol CT and chi2 = 29.03, P = 0.005<0.01vs HAP-MDCT). However, six nodules <10 mm in diameter were detected only by Lipiodol CT. CONCLUSION: MDCT and Lipiodol CT are two complementary modalities. At present, MDCT does not obviate the need for DSA and subsequent Lipiodol CT as a preoperative examination for HCC.

Angiography, Digital Subtraction↗

Megakaryocytopoiesis and apoptosis in patients with myelodysplastic syndromes.

In order to investigate simultaneously the megakaryocytopoiesis and apoptotic characteristics in bone marrow in patients with myelodysplastic syndromes (MDS), we used CD41 immunoenzyme (alkaline phosphatase anti-alkaline phosphatase) and DNA in situ end-labeling techniques on plastic embedded bone marrow biopsy sections of 29 MDS patients. Fourteen patients with iron deficiency anemia served as controls. The results showed that CD41-positive cells in MDS marrow numbered 26.2 +/- 18.2/mm2 (mean +/- standard deviation) compared with 15.6 +/- 7.1/mm2 in controls (P < 0.05). Numbers of cells with the morphology of micro-megakaryocytes in MDS marrow were significantly higher than in controls (P < 0.01). Furthermore, megakaryocytes in MDS marrow were frequently distributed along trabeculae (in 27 cases) and formed clusters (in 25 cases). Apoptotic megakaryocytes in MDS marrow accounted for just 4.4 and 9.3% of all CD41-positive cells and all apoptotic cells, respectively (P > 0.05 compared with controls), but apoptosis occurred only in micro-megakaryocytes. Based on these observations, we conclude that megakaryocytosis and dysmegakaryocytosis are the features of dyshematopoiesis in MDS marrow. Decreased thrombocyte production and thrombocyte release coming from increased dys(micro)megakaryocytes and abnormally located megakaryocytes perhaps play a more important role in peripheral thrombocytopenia than megakaryocytic apoptosis itself. Apoptosis of micro-megakaryocytes may be a protective biological mechanism to remove useless megakaryocytes.

Adolescent↗

Activated human umbilical cord blood dendritic cells kill tumor cells without damaging normal hematological progenitor cells.

Apart from their role as antigen presenting cells, human peripheral blood monocyte and CD34+ cell-derived dendritic cells (DC), have been demonstrated to exert cytotoxicity against some tumor cells, and their tumoricidal activity can be enhanced by some stimili. However, there have been no reports concerning the tumoricidal activity of human cord blood dendritic cells (CBDC). In this article, we report that human cord blood monocyte-derived DC acquire the ability to kill hematological tumor cells, after activation with lipopolysaccharide (LPS) or gamma-interferon (IFN-gamma), associated with the enhanced TNF-alpha-related apoptosis-inducing ligand (TRAIL) expression in CBDC cytoplasm. The CD14-positive cells collected from cord blood were induced to CBDC in vitro. After activation with IFN-gamma for 12 h, CBDC exhibited cytotoxicity against HL60 and Jurkat cells, while activation with LPS induced cytotoxicity against Daudi and Jurkat cells. However, both LPS- and IFN-gamma-stimulated CBDC showed no cytotoxic activity against normal CD14-negative cord blood mononuclear cells. The formation of umbilical cord hematopoietic progenitor colonies, identified as burst-forming unit-erythroid and colony-forming unit granulocyte-macrophage, was not inhibited by stimulated or unstimulated CBDC. IFN-gamma or LPS stimulation enhanced intracellular but not cellular surface TRAIL, and neither intracellular nor cellular surface tumor necrosing factor-alpha and Fas Ligand as analyzed by flow cytometry. Our results show that activated CBDC can serve as cytotoxic cells against hematological tumor cells without damaging the normal hematopoietic progenitor cells.

Antigens, CD34↗

[Anticarcinogenic effect of 20(R)-ginsenoside Rg3 on induced hepatocellular carcinoma in rats].

OBJECTIVE: To explore the anticarcinogenic mechanism of 20(R)-ginsenoside Rg3 in induced liver tumor in SD rat. METHODS: Thirty-five SD rats with induced hepatocellular carcinoma were divided into a control group and 3 dosage groups according to the dosing levels of 20(R)-ginsenoside Rg3. The tumour volume was measured by MR imaging. The apoptotic rat and S-phase fraction and diploid of tumor cell were measured with flow cytometry. Protein expression of PCNA and TNF were evaluated with immunohistochemistry. RESULTS: There was significant difference in tumour volume between the high dosage group and the control group. The average apoptotic rates were 11.08+/-3.78, 13.57+/-3.34, 27.35+/-16.04 and the S-phase fractions were 23.98+/-9.44, 19.73+/-6.62, 14.09+/-3.48 in the low-, medium-, and high-dosage groups respectively. The apoptotic rate was significantly higher in the high-dosage group than in the medium-dosage group and low-dosage group. Before-after comparison showed that the anti-proliferative effects of 20(R)-ginsenoside Rg3 were significant in three treatment groups. The higher positive rats of protein expression with PCNA and TNF were significant difference in the high-dosage group compared to those in the low-dosage group. No significant difference between the medium-dosage group and the low-dosage group. CONCLUSION: 20(R)-ginsenoside Rg3 can noticeably inhibit the proliferation of tumor cells, and efficaciously induce the apoptosis and facilitate necrosis of the tumor cells, and there appears to be a dose dependent effect.

Angiogenesis Inhibitors↗

[Clonal study on single apoptotic cells in myelodysplastic syndromes].

OBJECTIVE: To investigate the clonal origin of the apoptotic hematopoietic cells in myelodysplastic syndromes (MDS). METHODS: Nineteen patients with MDS whose karyotypes had been analysed with G- or R-binding were studied. ISEL (DNA in situ end labelling) and FISH (fluorescence in situ hybridization) (simplified as ISEL/FISH) were performed simultaneously in a single nucleated cells on cytospin slides in 10/19 of the patients. The ratio of FISH positive cells to all nucleated cells and to apoptotic cells were counted. Eight slides from 4 normal donors induced apoptosis by Fas monoclonal antibody (McAb) were used as methodology control. For the rest 9 patients, different fractions of cells (PI-, Annexin V+PI-, Annexin V-PI-) were sorted by flow cytometry and then cytospined for FISH analysis (simplified as FCM/FISH). RESULTS: The mean percentage of abnormal clonal cells in nuclear cells in the 10 cases detected by ISEL/FISH was 37.1%, whereas it was 24.0% in apoptotic cells. Induction by Fas McAb didn't lead to change of karyotype. Moreover, 8/9 patients analysed by FCM/FISH showed higher cell proportion with normal karyotypes in apoptosis-undergoing cells than that in non-apoptotic cells. CONCLUSION: Over apoptotic hematopoietic cells in MDS are mainly residual normal hematopoietic cells.

Adult↗

[Expression of insulin-like growth factor receptor type I in marrow nucleated cells from hematologic malignancies and its anti-apoptotic effect].

To explore the expression of insulin-like growth factor receptor type I (IGF-IR) and its relationship to apoptosis in hematopoietic cells of MDS and AML marrow, bone marrow nucleated cells from 16 patients with myelodysplastic syndrome (MDS) and 16 patients with acute myeloid leukemia (AML) were collected for analysis, respectively. Another 16 normal donors' marrow samples were taken as controls. Immunocytochemical method (APAAP) and TdT-mediated dUTP nick end labeling (TUNEL) fluorescence were used simultaneously on cytospins of nucleated cells from these patients. Then, the ratios of IGF-IR positive cells and apoptosis cells in all nucleated cells were counted separately. The results showed that (1) there was a higher IGF-IR expression rate (56.8 +/- 14.3)% in nucleated cells of MDS marrow than that in normal marrow (40.4 +/- 9.6)% (P < 0.01). Also IGF-IR positive rate in AML marrow (86.8 +/- 13.8)% was significantly higher than that in normal marrow (P < 0.01). Furthermore, IGF-IR had higher expression in AML marrow when compared to MDS marrow (P < 0.01); (2) apoptosis in nucleated cells of MDS marrow (5.4 +/- 3.0)% was significantly higher than that in normal marrow (1.2 +/- 0.9)% (P < 0.01) and AML marrow (0.3 +/- 0.4)% (P < 0.01), while there was less apoptosis in AML marrow than that in normal marrow (P < 0.01); (3) apoptosis occurred mainly in IGF-IR negative cells (9.0 +/- 4.8)% and less in IGF-IR positive cells (1.4 +/- 2.4)% (P < 0.01). IGF-IR expression showed negative correlation with apoptosis (r = -0.852, P < 0.01); (4) IGF-IR of MDS nucleated cells in RAEB/RAEB-t/CMML expressed higher than that in RA/RAS (64.1 +/- 3.2% vs 53.5 +/- 16.2%) subgroup, although no significant difference was found (P > 0.05); and apoptosis in RAEB/RAEB-t/CMML subgroup was lower than that in RA/RAS cases (3.1 +/- 2.1% vs 6.4 +/- 2.8%) (P < 0.05); (5) IGF-IR positive rate in nucleated cells of MDS and AML marrow showed positive correlation with blast rate (r = 0.677; P < 0.01). It is concluded that there is overexpression of IGF-IR in marrow nucleated cells in MDS and AML cases. And it seems that the overexpression of IGF-IR may suggest some malignant proliferation tendency and suppress cell apoptosis through some mechanism in these malignant hematologic ailments. So, anti-IGF-IR will become a new approach for therapy of MDS and AML.

Adolescent↗

[Induction of apoptosis in human hepatoma cell line SMMC7721 by Newcastle disease virus HN gene].

OBJECTIVE: To investigate the mechanisms of apoptosis induced in human hepatoma cell line SMMC7721 by plasmid pVHN constructed with Newcastle disease virus (NDV) HN gene. METHODS: Twenty-four h after transfection with liposome-plasmid pVHN complexes in vitro, the mortality rate of SMMC7721 cells was determined by MTT staining and flow cytometry (FCM) with PI staining. The alteration of mitochondrial trans-membrane potential of the cells was detected by FCM with rhodamine 123 staining. Cell genomic DNA was detected by agarose electrophoresis. The activation of caspase-3 was assayed by its substrate color reaction. RESULTS: Significant apoptosis was induced by transfection with plasmid pVHN into the cells for 24 h and the mortality rate was 50.0% (the mortality rate of control group was 5.2%). Genomic DNA was fragmented and mitochondrial trans-membrane potential was decreased, but caspase-3 activity increased. CONCLUSION: Significant apoptosis in SMMC7721 cells can be induced by NDV HN gene. Apoptosis may be resulted from the decrease of mitochondrial trans-membrane potential and activation of Caspase-3.

Apoptosis↗

[Effect of intestinal bacteria on metabolism of ophiopognin saponin D' in rats].

OBJECTIVE: To explore the metabolic transformation and the absorbed metabolites of ophiopognin saponin D' (OD') given orally in rats. METHOD: The contents of both original OD' and its metabolites were detected by means of HPLC-ELSD and the metabolites of OD' in blood and urine were measured by use of TLC and HPLC-MS in vivo. RESULT: OD' could be metabolized by intestinal bacteria in rats. The content of diosgenin, one of the metabolites, increased gradually as the time passed. CONCLUSION: OD' can be metabolized in intestine of rat and its metabolite, diosgenin, was absorbed in blood of rat.

Administration, Oral↗