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Biomedical subjects

Yong Sun

Publications and source records attributed to Yong Sun.

28 records · Page 2Linked to original sources
PubMed2003

Lung function after deep hypothermic cardiopulmonary bypass in infants.

There is increasing concern about neurologic injury due to deep hypothermia with low flow during repair of complex congenital heart defects in neonates and infants. Twenty infants with ventricular septal defect and pulmonary hypertension were randomly assigned to cardiac repair under deep hypothermia with circulatory arrest or deep hypothermia with low flow. Measurements of static pulmonary compliance, airway resistance, and respiratory index were performed before institution of cardiopulmonary bypass and at 5 minutes and 2 hours after cessation of cardiopulmonary bypass. Both groups had significant pulmonary dysfunction in terms of static pulmonary compliance, airway resistance, and respiratory index. There was greater impairment of pulmonary compliance and respiratory index after deep hypothermia with low flow, and this group required longer intensive care unit stay.

Cardiopulmonary Bypass↗
PubMed2003

Contribution of eIF-4E inhibition to the expression and activity of heparanase in human colon adenocarcinoma cell line: LS-174T.

AIM: Heparanase degrades heparan sulfate proteoglycans (HSPGs) and is a critical mediator of tumor metastasis and angiogenesis. Recently, it has been cloned as a single gene family and found to be a potential target for antimetastasis drugs. However, the molecular basis for the regulation of heparanase expression is still not quite clear. The aim of this study was to determine whether the expression of eukaryotic initiation factor 4E (eIF-4E) correlated with the heparanase level in tumor cells and to explore the correlation between heparanase expression and metastatic potential of LS-174T cells. METHODS: A 20-mer antisense s-oligodeoxynucleotide (asODN) targeted against the translation start site of eIF-4E mRNA was introduced into LS-174T cells by lipid-mediated DNA-transfection. eIF-4E protein and mRNA levels were detected by Western blot analysis and RT-PCR, respectively. Heparanase activity was defined as the ability to degrade high molecular weight (40-100 kDa) radiolabeled HS (heparan sulfate) substrate into low molecular weight (5-15 kDa) HS fragments that could be differentiated by gel filtration chromatography. The invasive potential of tumor cell in vitro was observed by using a Matrigel invasion assay system. RESULTS: The 20-mer asODN against eIF-4E specifically and significantly inhibited eIF-4E expression at both transcriptional and translational levels. As a result, the expression and activity of heparanase were effectively retarded and the decreased activity of heparanase resulted in the decreased invasive potential of LS-174T. CONCLUSION: eIF-4E is involved in the regulation of heparanase production in colon adenocarcinoma cell line LS-174T, and its critical function makes it a particularly interesting target for heparanase regulation. This targeting strategy in antisense chemistry may have practical applications in experimental or clinical anti-metastatic gene therapy of human colorectal carcinoma.

Adenocarcinoma↗
PubMed2003

[Modulation of iron on the vasodilating effect of interleukin-2 in the isolated aortic ring].

OBJECTIVE: To explore the effect and mechanism of iron on the vasodilating effect of interleukin-2 (IL-2) in the isolated aortic ring. METHODS: Isometric tension was recorded in response to drugs in organ bath. Ferric ammonium citrate (FAC) was added to the bath 30 min before phenylephrine (1 micromol/L), which was followed by IL-2 in a cumulative fashion. Spectrophotometry was used to determine the activity of nitric oxide synthase (NOS) of the thoracic aorta. RESULTS: FAC (0.1 - 10 micromol/L) alone did not affect the tension of rings,but inhibited the vasodilating effect of IL-2 (1 - 1,000 U/ml) in a dose dependent manner. IL-2(1, 10, 100, 1000 U/ml) decreased the aortic tension to (78.47+/-4.31)%, (66.86+/-5.55)%, (52.62+/-4.51)% and (42.39+/-4.27)% of pre-drug control, respectively. However, after incubation with 10 micromol/L FAC in the presence of IL-2, the aortic tension was reduced to (89.81+/-1.94)%, (86.13+/-3.11)%, (77.16+/-5.66)% and (68.76+/-5.69)% of pre-drug control, respectively. Pretreatment with L-arginine (1 mmol/L) abolished the inhibitory effect of FAC. Pretreatment with FAC attenuated the increased activity of NOS induced by IL-2 from (22.10+/-1.87)U/mg prot to (15.71+/-0.89)U/mg prot. High Ca(2+) (2.5 mmol/L) incubation did not change the inhibitory effect of FAC. Pretreatment with FAC attenuated the increased caffeine-releasable pool of Ca(2+) by IL-2. High K(+) (10 mmol/L) incubation abolished the inhibitory effect of FAC. CONCLUSION: FAC inhibits the vasodilating effect of IL-2 in the isolated aortic ring,which may be mediated by decreasing the activity of NOS. Intracellular calcium release and inward rectifier potassium channel are involved in the inhibitory effect of FAC.

Animals↗
PubMed2003

[The effects of bifidobacterium on the intestinal mucosa of the patients with ulcerative colitis].

OBJECTIVE: To investigate the effects of bifidobacterium (Bf) on the intestinal mucosa of the patients with ulcerative colitis (UC). METHODS: Thirty patients in clinical and endoscopic remission by sulphasalazine and glucocorticoid were randomized to receive either Bifid Triple Viable capsule (BIFICO), 420 mg/d, or an identical placebo (starch) for 8 weeks. Fecal samples were collected for stool culture before and after treatment. Patients were assessed clinically endoscopically and histologically after 2 months or in the case of a relapse. p65 and IkappaB expression was determined by Western blot analysis DNA-binding activity of NF-kappaB in colonic nuclear extracts was detected by electrophoretic mobility shift assay. The mRNA expression of cytokines were identified by a semi-quantitative assay, reverse transcription-polymerase chain reaction. RESULTS: Three patients in the BIFICO group had relapses within the 2-month follow-up period, compared with 14 in the placebo group (P < 0.01). Fecal concentration of lactobacilli, bifidobacteria, increased significantly from baseline levels only in the BIFICO-treated group (P < 0.01). The expression of NF-kappaB p65 and DNA binding activity of NF-kappaB were significantly attenuated in the treat group than that in control (P < 0.05). The mRNA expression of anti-inflammatory cytokines elevated obviously comparable of control group. CONCLUSIONS: The Bf maybe impede the activation of NF-kappaB, decrease the expression of TNF-alpha and IL-1beta and elevate the expression of IL-10. These results suggest that oral administration of this new probiotic preparation is effective in preventing flare-ups of chronic UC. It will become a prophylactic drug delaying the relapse of UC.

Adolescent↗
PubMed2003

[Surgical treatment of subluxated lens with cataract].

OBJECTIVE: To study the surgical treatment of the subluxated lens with cataract caused by broken suspensory ligament of the lens. METHODS: Phacoemulsification combined with intraocular lens implantation was performed in 21 eyes. Extracapsular cataract extraction with small-incision was performed in 6 eyes. The visual acuity, the position of IOL, and the postoperative complications were observed and analyzed. RESULTS: Postoperative vision was increased in all patients. Vision 3 days after the operation was 0.1 - 0.4 in 6 eyes and 0.5 - 0.8 in 21 eyes. Vision 1 month after the operation was 0.1 - 0.4 in 7 eyes and 0.5 - 0.8 in 20 eyes. The up-edge of IOL could be observed at normal pupil in only one eye. IOL positions were found to be diverged after dilation of the pupil in 2 eyes; no diplopia was experienced. There were no serious complications during or after the operation. CONCLUSION: If the operator has perfect skill and chooses the optimal method, a good result can be obtained in surgical treatment of the subluxated lens.

Aged↗
PubMed2002

[PCR cloning of 3'-terminal repeat fragments of Clostridium difficile toxin A and toxin B gene].

OBJECTIVE: To explore a method to rapidly detect the presence of Clostridium difficile. METHODS: PCR was used to amplify DNA fragments from the highly conserved and repeated domains of the 3'-terminal of Clostridium difficile toxin A gene and toxin B genes. RESULTS: The fragments 960 bp and 1,851 bp in length were respectively amplified from toxin A and toxin B, while the control bacteria presented no distinct results. CONCLUSION: The 960 bp and 1,851 bp fragments are specific for Clostridium difficile and PCR can be used to detect Clostridium difficile from the stool. As the peptides encoded by these conserved domains have high hydrophobicity and strong antigenicity, manufacture of the protein vaccine by gene engineering is possible on the basis of these conserved domains.

Bacterial Proteins↗
PubMed2002

[Neurotrophic factors and neural stem cells].

Neurotrophic factors includes nerve growth factors (NGF) family, glial cell line-derived neurotrophic factors (GDNF) family and other neurotrophic factors. NGF, BDNF, NT-3, NT-4/5 and NT-6 constitute NGF family (the neurotrophins), which may enhance both survival and differentiation of neurons from the EGF-responsive hippocampal and the subventricular zone neural stem cells. GDNF family includes GDNF, NTN, PSP and ART, whose major role is in peripheral neurodevelopment. This family enhance proliferation and survival of enteric neural crest precursor cells and is critical for the development of peripheral sensory nerve. Other growth factors such as bFGF and EGF can enhance proliferation and survival of neural stem cell. CNTF and LIF are critical for differentiation of neural stem cells.

Animals↗
PubMedDate not supplied

Ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation.

OBJECTIVE: to evaluate the efficacy and safety of ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation. METHODS: The study population consisted of 9 patients with 5 males and 4 females enrolled consecutively who had idiopathic paroxysmal atrial fibrillation(AF). The ultrasound balloon was positioned through a special sheath to the orifice of the target vein by a transseptal procedure. The balloon was inflated with contrast-mixed saline (contrast:saline = 1:4) whose volume was decided by the diameter of the target pulmonary vein. The ablation energy was usually set up at 35 to 40 watts with temperature controlled at 60 degrees C. The duration of each ablation was about 120 seconds which was repeated not over 10 times. RESULTS: The average duration of the total procedure was 132+/-68 min for our patients. The average fluoroscopy time was 33+/-17 min. With a mean follow-up of 16+/-8 months after the procedure, AF was completely eliminated in 4 patients without antiarrhythmic drugs. The episodes of atrial fibrillation were eliminated in 2 patients with low dosage of oral amiodarone (0.1, once daily) which was ineffective before the procedure. The frequency of episodes was similar to that before the procedure in 3 patients. There were no complications such as hemopericardium, air embolism and stenosis of the pulmonary veins by angiography, related to the procedure. CONCLUSION: Ultrasound ablation of the pulmonary veins is a new approach to treat paroxysmal atrial fibrillation. Before we determined its value, we need to do more researches with bigger sample, randomization and comparison design.

Adult↗