Biomedical subjects

Xiao Li

Publications and source records attributed to Xiao Li.

70 records · Page 4Linked to original sources

PubMed2003

[Expression of epidermal growth factor receptor and its relationship to apoptosis in myelodysplastic syndromes].

OBJECTIVE: To explore the expression of epidermal growth factor receptor (EGFR) in hematopoietic cells and investigate its relationship to apoptosis in myelodysplastic syndrome (MDS) patients. METHOD: Mononuclear cells from 18 MDS patients were used to analyze the expression of EGFR and the apoptotic signals by immunocytochemical technique and TdT-mediated dUTP nick end labelling (TUNEL) fluorescein. Flow cytometry (FCM) sorted CD(34)(+) cells from 15 MDS cases and 6 normal donors were also analyzed for the EGFR expression and apoptotic signals. Nine normal marrow samples were taken as controls. EGFR expression and its relationship to apoptosis were analysed. RESULTS: (1) There was a higher EGFR expression rate (38.6 +/- 24.6)% in nucleated cells of MDS marrow than in normal marrow (18.1 +/- 14.0)% (P < 0.05). (2) Apoptosis occurred much more in EGFR negative cells (16.1%) than in EGFR positive cells (1.4%) (P < 0.01). EGFR expression showed negative correlation with apoptosis (r = -0.701; t(r) = 3.60; P < 0.01). (3) In CD(34)(+) cells, EGFR expression rate seemed higher in RAEB/RAEB-t/CMML than that in RA/RAS (20.6 +/- 27.9 vs 8.9 +/- 11.8%) subgroup (P > 0.05), while apoptosis was lower in RAEB/RAEB-t/CMML subgroup than in RA/RAS cases (18.2 +/- 12.5 vs 45.2 +/- 20.5%) (P < 0.05). CONCLUSION: There is overexpression of EGFR in MDS cases. And it seems that the overexpressed EGFR represent somewhat the malignant proliferation in MDS and suppress apoptosis through a unknown mechanism.

Adult↗

PubMed2003

[Scanning electron microscope observation of the effect of different dentin bonding surfaces on the bonding interface].

To study the microstructural influence of dry or wet dentin bonding surface on the dentin bonding interface, five wet bonding systems were used to bond Chrisma B20 resin with dry or moist dentin surface with scanning electron microscope. All these systems were found to be well able to infiltrate into the dentin bonding interface on wet dentin surface, and significant changes occurred in the bonding interface when acetone-based adhesives were applied on dry dentin surfaces, demonstrating thinner hybrid layer and the formation of partially hybrid region, while alcohol- and water-based adhesives showed no changes. The necessity of moist dentin surface is therefore suggested when wet bonding systems are used.

Dental Bonding↗

PubMed2003

[Relationship between macrophages and apoptosis in patients with myelodysplastic syndromes].

OBJECTIVE: To observe the relationship between macrophage proliferation and cell apoptosis in patients with myelodysplastic syndromes (MDS). METHODS: A double labelling method of immunohistochemistry (alkaline phosphatase anti-alkaline phosphatase, APAAP) and ISEL (DNA in situ end labelling) was used to detect the positive CD68 expression (macrophages) and apoptosis on cold plastic embedded bone marrow biopsy sections in 30 MDS cases. 12 cases of iron deficient diseases (IDA) were used as the control. RESULTS: (1) The number of CD68 positive cells in MDS were higher than that in controls (29.2 +/- 33.0/mm(2) bone marrow tissue vs 21.2 +/- 16.7/mm(2)) (P > 0.05); (2) The number of apoptotic cells in MDS group was much higher than that in the controls (71.5 +/- 70.9/mm(2) vs 37.3 +/- 23.0/mm(2), P < 0.05); (3) The number of CD68 expression (35.5 +/- 37.0/mm(2)) and apoptosis (90.7 +/- 74.6/mm(2)) in less advanced MDS were much higher than that in advanced MDS group (14.6 +/- 11.7/mm(2) and 26.8 +/- 33.1/mm(2), P < 0.05 and < 0.01 respectively); (4) CD68 expression showed an obvious positive correlation to apoptosis in MDS cases (r = 0.83, P < 0.001); (5) CD68 positive cells did not show location correlation to apoptotic cells; (6) CD 68 positive cells in MDS showed simultaneous apoptosis. CONCLUSIONS: Over-apoptosis existed in MDS. Less advanced group has a higher ratio of apoptosis than in advanced group. The correlation between macrophages and apoptosis indicates the participation of TNFalpha in apoptosis-induction during MDS development.

Adolescent↗

PubMed2003

[Apoptotic characteristics of CD34 positive cells in myelodysplastic syndromes].

OBJECTIVE: To investigate the apoptotic situation of CD(34) positive cells in myelodysplastic syndromes (MDS). METHOD: In 36 MDS patients, immunocytochemical technique was used for the detection of the expression of CD(34) antigen and DNA in situ end labelling (ISEL) (fluorescein) for the apoptotic signals. Fourteen cases of iron deficiency anemias (IDA) were used as controls. RESULTS: (1) CD(34) expression in MDS group was much higher than that in controls (49.2 +/- 38.5 vs 10.2 +/- 9.7, P < 0.01), and MDS cases had an obviously higher apoptotic rate than control did (69.1 +/- 28.2 vs 17.8 +/- 11.2, P < 0.01). (2) Expression of CD(34) was higher in transforming group (P < 0.05) than in non-transforming and post-transforming groups. Apoptotic rates in both non-transforming/transforming group were higher than in post-transforming group (P < 0.02 and < 0.05 respectively). (3) No apoptosis was found in CD(34) positive cells in MDS; (4) Both CD(34) positive cells and apoptotic cells formed into small or large clusters but did not co-distributed in a given area. CONCLUSION: There is overexpression of CD(34) antigen on hematopoietic cells in MDS. High CD(34) expression accompanied high apoptosis coexisted in the process of transformation from MDS to AML. Apoptosis-resistance of these CD(34) positive cells suggested that they came from malignant hematopoietic cell clones.

Adolescent↗

PubMed2003

[Experimental study on apoptosis in T cells induced by ovarian carcinoma cells].

OBJECTIVE: To investigate apoptosis in T cells induced by ovarian carcinoma cells and analyze the role of nitric oxide and intracellular free calcium in this process. METHODS: Apoptosis induced by ovarian carcinoma cell lines supernatants was investigated by electron microscopy and flow cytometry. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect the expression of inducible nitric oxide synthase (iNOS) mRNA. Calcium ions ([Ca(2+)]i) and cycle guanosine monophosphate (cGMP) were determined by Fura-2 fluorescein load technique and enzyme immunoassay (EIA), respectively. RESULTS: Cluster of differentiation (CD)8(+) T cells cocultured with ovarian carcinoma cell lines supernatants expressed typical change of apoptosis, such as condensation and fragmentation of chromosomes, apoptosis peak in flow cytometry and higher apoptotic ratios[(23.8 +/- 3.5)%, (23.1 +/- 2.9)%, (24.2 +/- 4.9)% vs (4.6 +/- 0.5)%, P < 0.01]. The expression of iNOS mRNA and cGMP level in the process of CD(8)(+) T cellular apoptosis were significantly enhanced as compared to that of control group [1.14 +/- 0.03, 1.05 +/- 0.04, 1.16 +/- 0.02 vs 0.60 +/- 0.03, P < 0.01; (0.65 +/- 0.09), (0.62 +/- 0.16), (0.57 +/- 0.12) pmol/Lvs (0.29 +/- 0.04) pmol/ml, P < 0.01], and [Ca(2+)]i was significantly higher [(380 +/- 38), (366 +/- 13), (356 +/- 20) nmol/L vs (184 +/- 11) nmol/L, P < 0.01]. CONCLUSION: Nitric oxide and intracellular free calcium may play a key role in apoptotic T cell induced by ovarian carcinoma.

Apoptosis↗

PubMed2003

[Biological distribution of 131I-HAb18F(ab')2 in patients with hepatocellular carcinoma].

Before 131I-HAb18F(ab')2 administration, 24 cases of mid-term or advanced hepatocellular carcinoma(HCC) were given Lugol's Liquid to block the thyroid gland, and submitted to hepatic colloid imaging. The cases were randomly divided into 3 groups. Then 131I-HAb18F(ab')2 was injected into the target hepatic artery with doses of 0.5, 0.75, 1.0 mCi/kg, respectively. At the followed 10, 48, 96 and 192 hours, 131I-HAb18F(ab')2 distribution in human body was acquired by whole body dynamic image with Single photon emission computed tomography(SPECT). The results showsed that 131I-HAb18F(ab')2 in tumor tissue was significantly higher than that in normal liver tissue and other organs. This difference became obvious as time passed. 131I-HAb18F(ab')2 is stable in human body and it can combine with HCC tissue specifically. So it is a new medicine deserving further research for the treatment of HCC.

Adult↗

PubMed2002

Receptive field organization and response properties of visual neurons in the pigeon nucleus semilunaris.

The present study provides the first electrophysiological evidence that the nucleus semilunaris is a visual center in the pigeon midbrain. The receptive field of E-type cells is either an excitatory field alone or an excitatory center with an inhibitory periphery, which in most cases is surrounded by a disinhibitory region. Cells of I-type possess only an inhibitory receptive field. Semilunar cells are selective for fast (80-160 degrees /s), intermediate (40 degrees /s) and slow (10-20 degrees /s) velocities of motion, with directional cells mainly preferring forward and downward motion. About 40% of cells prefer a white stimulus moving against a black background, and 60% of cells prefer a black stimulus against a white background. The physiological significance of these properties is discussed.

Animals↗

PubMed2002

Modulation by oxytocin of ATP-activated currents in rat dorsal root ganglion neurons.

The modulatory effect of oxytocin (OT) on ATP-activated currents (I(ATP)) was studied in freshly isolated dorsal root ganglion (DRG) neurons of rats using whole cell clamp technique. In most of the neurons examined (50/70, 71.4%) extracellular application of OT (10(-9)-10(-5) mol/L) suppressed I(ATP) while in the rest (20/70, 28.6%) no modulatory effect was observed. OT shifted the ATP concentration-response curve downwards with a decrease of 39.8+/-4.2% in the maximal current response and with no significant change of Kd value. This OT-induced inhibition of I(ATP) showed no voltage dependence, and could be blocked by [d(CH(2))(5),Tyr(Me)(2),Thr(4),Tyr-NH(2)(9)]-OVT (d(CH(2))(5)-OVT) (10(-8) mol/L), a specific OT receptor antagonist. Intracellular application of H-9 (4 x 10(-5) mol/L, an inhibitor of protein kinase A) (n=12), BAPTA (10(-2) mol/L, a chelator of calcium ions) (n=4) could reverse the inhibitory effect of extracellular OT (10(-7) mol), while inclusion of H-7 (2 x 10(-5) mol/L, a protein kinase C inhibitior) (n=8) and KN-93 (10(-5) mol/L, an inhibitor of CaMKII) (n=9) in the recording pipette did not affect this effect. The results suggested that OT inhibition on ATP-activated currents was mediated by OT receptors in the membrane of DRG neurons; and this inhibitory effect involved the transduction of intracellular cAMP-PKA and Ca(2+).

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed2002

[Study on apoptosis in myelodysplastic syndromes by DNA in situ end labelling combined with APAAP].

OBJECTIVE: To investigate the total in situ apoptotic cell number and the apoptotic situation in erythroid cell and megakaryocytes in patients with myelodysplastic syndromes (MDS). METHODS: Apoptosis cell number and the apoptotic situation of erythroid cell and megakaryocytes were analysed on cold embedded bone marrow sections from 25 MDS patients by DNA in situ end labelling (ISEL)/alkaline phosphatase anti-alkaline phosphatase (APAAP) double stained techniques. Fourteen cases of iron deficiency anemia (IDA) were taken as control. RESULTS: Mean apoptotic cell numbers in MDS and control group were (39.44 +/- 29.34)/mm(2) and (13.43 +/- 8.39)/mm(2) respectively (P < 0.01). RA/RAS subtypes had a higher apoptosis ratio (47.56 +/- 32.86/mm(2)) than that in RAEB/RAEB-t subtypes (21.87 +/- 13.65/mm(2)) (P < 0.05). Double staining showed similar apoptosis percentage in erythroid cell and megakaryocytes in MDS patients comparing with that of controls (P > 0.05). Some apoptotic cells showing erythroid or megakaryocytic morphologic characteristics expressed no cluster differentiation antigen. CONCLUSION: Overapoptosis existed in MDS, RA/RAS group had a higher apoptosis ratio than RAEB/RAEB-t group. No obvious increased apoptosis in erythroid cell and megakaryocytes was observed in MDS perhaps due to the loss of surface antigens in later stages of apoptotic cells.

Adolescent↗

PubMed2002

[Study about proliferation and apoptosis of megakaryocytes in patients with myelodysplastic syndromes].

In order to observe the proliferative and apoptotic situation of megakaryocytes in patients with myelodysplastic syndromes (MDS). CD41 immunoenzyme labeling (alkaline phosphatase anti-alkaline phosphatase APAAP)/DNA in situ end labelling (ISEL) double stained techniques was used onto plastic cold embedded bone marrow sections in 29 MDS patients to analyse the proliferative and apoptostic characterization of megakaryocytic line with 14 cases of iron deficient diseases (IDA) as control. The results showed that the mean CD41 positive cell number in MDS group was (26.23 +/- 8.18) /mm(2) with a count of (15.64 +/- 7.11) /mm(2) in control group (p < 0.05). The small-micro megakaryocytes in MDS is much higher than that in IDA group (P<0.01). There was a positive co-relation between total megakaryocytes and small-micro megakaryocytes count in MDS (r = 0.702, p<0.01). Some megakaryocytes distributed abnormally around trabecula and formed small or large clusters. Apoptotic megakaryocytes in MDS occupied 4.40% and 9.32% of all CD14 positive cells and all apoptotic cells respectively (p > 0.5 comparing with control). Apoptosis in megakargocytic line occurred only in small-micro megakaryocytes and showed positive co-relation to the number of micro-megakaryocytes. Some apoptotic cell with morphologic characters of megakaryocytes expressed no CD41. It is concluded that overproliferation of megakaryocytes exists in MDS. Apoptosis occurring in micro-megakaryocytes may be a kind of physiological response to abnormal megakaryopoicsis in MDS. No obvious increased apoptosis of megakaryocytes in MDS was found perhaps due to lack of surface antigens CD41 in some later stages of apoptotic cell.

Adolescent↗

PubMed2002

[Effect of changtong oral liquids on the fibrinolytic activity of rabbits with experimental intestinal adhension].

OBJECTIVE: To observe the effect of Changtong Oral Liquid (CTOL) on the fibrinolytic activity of rabbits with experimental intestinal adhesion. METHODS: Intestinal adhesion model of rabbits were made with reference to that described by Thomas and Rhoads and the animals were continuously orally supplemented with CTOL for seven days. Changes of tissue plasminogen activator (t-pA) and plasminogen activator inhibitor activity (PAI) as well as the intestinal adhesion were investigated. RESULTS: Different dosage of CTOL produced protective effects on the postoperative intestinal adhesion accompanied by significant enhancement of t-PA activity and pronounced decreasement of PAI activity. CONCLUSION: CTOL maybe play protective role in postoperative intestinal adhesion by modulating the activity of fibrinolytic system.

Animals↗

PubMed2000

Role of P-selectin and anti-P-selectin monoclonal antibody in apoptosis during hepatic/renal ischemia reperfusion injury.

AIM:To evaluale the potential role of P-selectin and anti-P-selectin monoclonal antibody (mAb) in apoptosis during hepatic/renal ischemia-reperfusion injury.METHODS:Plasma P-selectin level, hepatic/renal P-selectin expression and cell apoptosis were detected in rat model of hepatic/renal ischemia-reperfusion injury.ELISA,immunohist ochemistry and TUNEL were used. Some ischemia-reperfusion rats were treated with anti-P-selectin mAb.RESULTS:Hepatic/renal function insuffic-iency, up-regulated expression of P-selectin in plasma and hepatic/renal tissue, hepatic/renal histopathological damages and cell apoptosis were found in rats with hepatic/renal ischemia-reperfusion injury, while these changes became less conspi-cuous in animals treated with anti-P-selectin mAb.CONCLUSION:P-selectin might mediate neutrophil infiltration and cell apoptosis and contribute to hepatic/renal ischemia-reperfusion injury, anti-P-selectin mAb might be an efficient approa-ch for the prevention and treatment of hepatic/renal ischemia reperfusion injury.

Journal Article↗

PubMedDate not supplied

N-nitrosodiethylamine-induced pig liver hepatocellular carcinoma model: radiological and histopathological studies.

Experimental research involving animal models plays a critical role in the development and improvement of minimally invasive therapies for hepatocellular carcinoma (HCC). As a large animal, the pig is commonly used for surgery and interventional radiology research. In this study, liver multicentric HCC with cirrhosis was induced in six China Taihu pigs by intraperitoneal injection of 10 mg/kg of N-nitrosodiethylamine once a week for 3 months, followed by a period of 10-12 months without N-nitrosodiethylamine treatment. All pigs were in generally good health until the end of the study. The tumor nodules appeared hyperattenuating in the arterial phase of a dynamic computed tomography (CT) scan. Digital subtraction angiography (DSA) and CT angiography demonstrated that the tumors derived their blood supply mainly from the hepatic artery system. Lipiodol-CT showed Lipiodol retention in tumor areas. The histology and electron microscopic ultrastructure of the chemically induced liver HCC in this study resembled human HCC with a cirrhosis background. An immunohistochemistry study confirmed that the tumors were of hepatocyte origin. All highly, moderately, and poorly differentiated HCC tumors were identified in this study. Cholangiocarcinoma was not seen in any of the animals. Due to its comparable size to human anatomy, the pig liver HCC model would give a better scope for interventional and surgical manipulations than small animal models.

Alkylating Agents↗

PubMedDate not supplied

Catheterization of the hepatic artery via the left common carotid artery in rats.

The commonly used approach for rat hepatic artery catheterization is via the gastroduodenal artery, which is ligated after the procedure. A new method of rat hepatic artery catheterization via the left common carotid artery (LCCA) is described. The LCCA is repaired after catheterization. The catheterization procedures included the following: (1) opening the rat's abdominal cavity and exposing the portion of abdominal aorta at the level of the celiac trunk; (2) separating and exposing the LCCA; inserting a microguidewire and microcatheter set into the LCCA via an incision; after placement into the descending aorta, the microguidewire and microcatheter are maneuvered into the hepatic artery under direct vision; (3) after transcatheter therapy, the catheter is withdrawn and the incision at the LCCA is repaired. This technique was employed on 60 male Sprague-Dawley rats with diethylnitrosamine-induced liver cancer, using a 3F microguidewire and microcatheter set. Selective hepatic artery catheterization was successfully performed in 57 rats. One rat died during the operation and five rats died within 7 days after the procedure. It is envisaged that as experience increases, the catheterization success rate will increase and the death rate will decrease. A new approach for selective hepatic artery catheterization via the LCCA in rats is introduced, which makes repeat catheterization of this artery possible and allows large embolization particles to be delivered by using a 3F catheter.

Alkylating Agents↗

PubMedDate not supplied

Thermodynamic studies on the adsorption of fibronectin adhesion-promoting peptide on nanothin films of poly(2-vinylpyridine) by SPR.

This paper describes a methodology for preparing uniform, nanothin polymer films for the study of biomolecule adsorption by surface plasmon resonance spectroscopy (SPR). The methodology combines molecular self-assembly of alkanethiols on gold with surface-confined atom transfer radical polymerization (ATRP). Poly(2-vinylpyridine) was chosen to demonstrate the methodology, and growth kinetics were studied by ex situ ellipsometry. Atomic force microscopy (AFM) indicated that the polymer films were uniform with RMS roughness of approximately 0.5 nm. Subsequent SPR measurements were done to determine thermodynamic adsorption properties (deltaG, deltaH, and deltaS) between fibronectin adhesion-promoting peptide and the surface-confined poly(2-vinylpyridine) at 15, 20, and 25 degrees C. The flexibility in synthesis conditions and the opportunities for manipulating film thicknesses and graft densities that ATRP provides to grow polymer films from gold surfaces holds advantages over conventional spin-coating and grafting to approaches in the design of model polymer films for biomolecule adsorption studies. These advantages are described.

Adsorption↗

PubMedDate not supplied

Surface molecular imprinting by atom transfer radical polymerization.

Results are presented that demonstrate the successful preparation of ultrathin (< 10 nm), surface-confined, molecularly imprinted polymer (MIP) films on model gold substrates using atom transfer radical polymerization (ATRP). 2-Vinylpyridine (2Vpy) was investigated as the functional monomer, and ethylene glycol dimethacrylate (EGDMA) was the cross-linking monomer. Fluorescently labeled N,N'-didansyl-L-cystine and N,N'-didansyl-L-lysine were used as the template molecules to form the MIPs. Spectroscopic and ellipsometric results are presented that follow film formation and growth rates. Results are also presented from fluorescence experiments used to quantify and compare the adsorption capacities of MIP surface films and nonimprinted (NIP) control films. MIP films exhibited higher binding capacities than the control NIP films at all solution concentrations of N,N'-didansyl-L-cystine and N,N'-didansyl-L-lysine. Furthermore, template removal from these imprinted films appears to be 100% efficient. Selectivity studies showed that the MIPs display some cross-reactivity between these two molecules; nevertheless, MIPs prepared against one template showed selectivity for that template. A selectivity coefficient of 1.13 was achieved for MIP surfaces prepared against N,N'-didansyl-L-lysine; a value of 1.51 was observed for MIP surfaces prepared against N,N'-didansyl-L-cystine.

Adsorption↗