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Biomedical subjects

Jun Xu

Publications and source records attributed to Jun Xu.

At least 163 records · Page 9Linked to original sources
PubMed2004

Atrial extracellular matrix remodeling and the maintenance of atrial fibrillation.

BACKGROUND: Remodeling occurs in both ventricle and atrium in dilated cardiomyopathy and heart failure. However, the alteration of atrial extracellular matrix components during remodeling and its effect on the electrical remodeling and atrial arrhythmia have never been explored. METHODS AND RESULTS: Atrial tissue samples of 53 explanted hearts from patients with dilated cardiomyopathy and end-stage heart failure who underwent heart transplantation were examined. Nineteen patients had permanent atrial fibrillation (PmAF), 18 had persistent AF (PsAF), and 16 had no documented AF (NAF). Sixteen donor left atria (LA) were used as controls (CNs). Western Blot analysis revealed a selective downregulation of tissue inhibitor of metalloproteinase (TIMP)-2 in PmAF and PsAF groups compared with the NAF and CN groups and an upregulation of atrial metalloproteinase (MMP)-2 that was most pronounced in the PmAF group followed by the PsAF and NAF groups. Immunofluorescent staining revealed that in the LA, type I collagen volume fraction (CVF-I) increased significantly in the PmAF group followed by the PsAF and NAF groups compared with that in CN. LA CVF-I significantly correlated with LA dimension and TIMP-2 to MMP-2 ratio. In the PsAF group, CVF-I/CVF-III ratio was significantly correlated with AF duration and the frequency of AF recurrence. CONCLUSIONS: Atrial extracellular matrix remodeling manifested by the selective downregulation of TIMP-2 along with upregulation of MMP-2 and CVF-I in the atrium is associated with the development of sustained atrial fibrillation in patients with cardiomyopathy and heart failure.

Atrial Fibrillation↗
PubMed2004

Identification and characterization of 4-[[4-(2-butynyloxy)phenyl]sulfonyl]-N-hydroxy-2,2-dimethyl-(3S)thiomorpholinecarboxamide (TMI-1), a novel dual tumor necrosis factor-alpha-converting enzyme/matrix metalloprotease inhibitor for the treatment of rheumatoid arthritis.

Tumor necrosis factor (TNF)-alpha is a well validated therapeutic target for the treatment of rheumatoid arthritis. TNF-alpha is initially synthesized as a 26-kDa membrane-bound form (pro-TNF) that is cleaved by a Zn-metalloprotease named TNF-alpha-converting enzyme (TACE) to generate the 17-kDa, soluble, mature TNF-alpha. TACE inhibitors that prevent the secretion of soluble TNF-alpha may be effective in treating rheumatoid arthritis (RA) patients. Using a structure-based design approach, we have identified a novel dual TACE/matrix metalloprotease (MMP) inhibitor 4-[[4-(2-butynyloxy)phenyl]sulfonyl]-N-hydroxy-2,2-dimethyl-(3S)thiomorpholinecarboxamide (TMI-1). This molecule inhibits TACE and several MMPs with nanomolar IC(50) values in vitro. In cell-based assays such as monocyte cell lines, human primary monocytes, and human whole blood, it inhibits lipopolysaccharide (LPS)-induced TNF-alpha secretion at submicromolar concentrations, whereas there is no effect on the TNF-alpha mRNA level as judged by RNase protection assay. The inhibition of LPS-induced TNF-alpha secretion is selective because TMI-1 has no effect on the secretion of other proinflammatory cytokines such as interleukin (IL)-1beta, IL-6, and IL-8. Importantly, TMI-1 potently inhibits TNF-alpha secretion by human synovium tissue explants of RA patients. In vivo, TMI-1 is highly effective in reducing clinical severity scores in mouse prophylactic collagen-induced arthritis (CIA) at 5, 10, and 20 mg/kg p.o. b.i.d. and therapeutic CIA model at 100 mg/kg p.o. b.i.d. In summary, TMI-1, a dual TACE/MMP inhibitor, represents a unique class of orally bioavailable small molecule TNF inhibitors that may be effective and beneficial for treating RA.

ADAM Proteins↗
PubMed2004

The diapause hormone-pheromone biosynthesis activating neuropeptide gene of Helicoverpa armigera encodes multiple peptides that break, rather than induce, diapause.

FXPRLamide peptides encoded by the DH-PBAN (diapause hormone-pheromone biosynthesis activating neuropeptide) gene induce embryonic diapause in Bombyx mori, but terminate pupal diapause in Helicoverpa armigera (Har). Here, we explore the mechanisms of terminating pupal diapause by the FXPRLamide peptides. Using quantitative RT-PCR, we observed that expression of Har-DH-PBAN mRNA in the SG of nondiapause-type pupae was significantly higher than in diapause-type pupae. Immunocytochemical results indicated that the level of FXPRLamide peptides and axonal release are related to the diapause decision. Ecdysteroidogenesis in prothoracic glands (PGs) was stimulated by synthetic Har-DH in vivo and in vitro, and labeled Har-DH bound to the membrane of the PG, thus suggesting that DH breaks diapause by activating the PG to synthesize ecdysone. Furthermore, the response of DH in terminating diapause was temperature dependent. Decerebration experiments showed that the brain can control pupal development through the regulation of DH, and DH can terminate diapause and promote development without the brain. This result suggests a possible mechanism of response for the signals of DH and other FXPRLamide peptides in H. armigera.

Animals↗
PubMed2004

TEM investigation on the growth mechanism of carbon nanotubes synthesized by hot-filament chemical vapor deposition.

Carbon nanotubes (CNTs) were synthesized using hot-filament chemical vapor deposition on Ni film-coated Si substrate. The CNTs were well-aligned perpendicular to the substrate. The as-grown CNTs were bamboo-like in their morphology, and were investigated using SEM and high-resolution transmission electron microscopy (HRTEM). The SEM and HRTEM studies show that the both ends of a CNT contain metallic catalytic particles, which is different from results previously reported. Our analysis results provide strong evidence that the metallic catalyst remains in a liquid state during nanotube growth. The upward-growth pulling force of the CNT layer elongates the liquid nanoparticles, which are finally broken into two parts. One part remains at the substrate surface (base of the CNTs) and is responsible for the catalytic growth of the CNTs. The other part is enclosed at the tip of the CNTs and is inactive during CNT growth.

Journal Article↗
PubMed2004

Inhibition of ocular angiogenesis by siRNA targeting vascular endothelial growth factor pathway genes: therapeutic strategy for herpetic stromal keratitis.

Ocular neovascularization often results in vision impairment. Frequently vascular endothelial cell growth factors (VEGFs) are mainly responsible for the pathological neovascularization as in the case in neovascularization induced by CpG oligodeoxynucleotides and herpes simplex virus infection in this report. siRNAs targeting either VEGFA, VEGFR1, VEGFR2, or a mix of the three were shown to significantly inhibit neovascularization induced by CpG when given locally or systemically. The efficacy of systemic administration was facilitated by the use of a polymer delivery vehicle. Additional experiments showed a significant inhibitory effect of the siRNAs mix when given either locally or systemically in vehicle against herpes simplex virus-induced angiogenesis as well as against lesions of stromal keratitis. These results indicate that the use of VEGF pathway-specific siRNAs represents a useful therapy against neovascularization-related eye diseases.

Animals↗
PubMed2004

Complex spatial distribution and dynamics of an abundant Escherichia coli outer membrane protein, LamB.

Advanced techniques for observing protein localization in live bacteria show that the distributions are dynamic. For technical reasons, most such techniques have not been applied to outer membrane proteins in Gram-negative bacteria. We have developed two novel live-cell imaging techniques to observe the surface distribution of LamB, an abundant integral outer membrane protein in Escherichia coli responsible for maltose uptake and for attachment of bacteriophage lambda. Using fluorescently labelled bacteriophage lambda tails, we quantitatively described the spatial distribution and dynamic movement of LamB in the outer membrane. LamB accumulated in spiral patterns. The distribution depended on cell length and changed rapidly. The majority of the protein diffused along spirals extending across the cell body. Tracking single particles, we found that there are two populations of LamB--one shows very restricted diffusion and the other shows greater mobility. The presence of two populations recalls the partitioning of eukaryotic membrane proteins between 'mobile' and 'immobile' populations. In this study, we have demonstrated that LamB moves along the bacterial surface and that these movements are restricted by an underlying dynamic spiral pattern.

Bacterial Outer Membrane Proteins↗
PubMed2004

[Vertical mammaplasty using the skin wrinkling suture techniques].

OBJECTIVE: To reduce the incision scar produced by reduction mammaplasty. METHODS: The periareola incision and the vertical incision below the areola were made when performing breast reduction. The incision in the submammary fold was avoided. The breast was suspended and moulded. The redundant skin and the long skin incision below the areola were sutured utilizing the skin wrinkling suture techniques. The wrinkling skin and incision became flat gradually due to the elasticity of the tissue itself. RESULTS: 13 cases have been treated with the techniques mentioned above. All incisions healed primarily and there were no complications such as hematoma, infection and necrosis of skin or areola. Of them, 3 patients with very large and ptotic breasts needed small corrective operations to excise the redundant skin that still existed 6 months postoperatively. The shape of the breasts and the vertical incision scars of the other patients were satisfactory. CONCLUSIONS: The vertical mammaplasty using the skin wrinkling suture techniques can be used in breast reduction of various sizes, owing to the advantages of consistent, good and stable result, simplicity to perform and grasp and no scar in the submammary fold.

Adult↗
PubMed2004

[Anatomic study of perforator neurovascular bundles of the deep inferior epigastric perforator flap].

OBJECTIVE: To investigate the anatomic characteristics of the perforator neurovascular bundles in the anterior abdominal wall for the anatomical basis of the sensate deep inferior epigastric perforator (DIEP) flap. METHODS: Abdominal wall dissection was performed on 9 embalmed female cadavers (18 sides). RESULTS: Most of the deep inferior epigastric perforators emerged at the anterior sheath of the rectus. There were averaged 17.5 perforators on each side, with the diameter equal to or larger than 0.5 mm in 7.8 perforators. The number of skin perforators was the greatest in the supero-medial area. 56.2 percent of vascular perforators traveled with the sensory branches while 80.9 percent of larger perforators (> or = 0.5 mm in diameter) run with the sensory branches. CONCLUSIONS: The lateral perforator neurovascular bundle was the first choice in the design of the sensate DIEP flap.

Abdominal Wall↗
PubMed2004

[Effect of Radix notoginseng saponins on platelet activating molecule expression and aggregation in patients with blood hyperviscosity syndrome].

OBJECTIVE: In order to explore the relationship between the active components and the functional links of Chinese herbs, the effect of Xuesaitong capsule, a preparation made of multi-component Panax notoginseng saponins (PNS) on platelet activating molecule expression and aggregation in patients with blood hyperviscosity syndrome (BHS) was observed, with aspirin (ASP) as a control. METHODS: One hundred and twenty patients with BHS were divided, adopting randomized, double-blinded and double simulated principle into 2 groups, the PNS group and the ASP group, 60 in each group. Changes of the TCM clinical syndrome, platelet adhesion and aggregation, endothelin (ET), prostacyclin, thromboxane, CD62P and CD41 before treatment and after 28 days treatment were observed. RESULTS: Comparison between the therapeutic effects of the two groups on TCM clinical syndrome showed that the total effective rate in the PNS group was 86.67% and that in the ASP group 56.67%, showing significant difference (P < 0.05). Compared with before treatment, after treatment, levels of platelet adhesion and aggregation, endothelin, prostacyclin and thromboxane were significantly different in both groups (P < 0.05 or P < 0.01); levels of CD62P and CD41 in the PNS group were also significantly different, but the difference was insignificant in the ASP group; no significant difference was shown in both groups in levels of triglyceride, total cholesterol and very low density lipoprotein-cholesterol. CONCLUSION: PNS may inhibit activation of platelet through multiple components and multiple pathways, which is different from that of ASP, only through inhibition on arachidonic acid metabolism to suppress platelet aggregation. PNS has effects of decreasing platelet superficial activation, inhibiting platelet adhesion and aggregation, preventing thrombosis and improving microcirculation, and its therapeutic effect on clinical syndrome is better than that of ASP.

Aged↗
PubMed2004

[Protective effect of specific antibody in serum of convalescent patient with SARS].

OBJECTIVE: To investigate inhibitory effect of serum severe acute respiratory syndrome (SARS) -specific antibodies from convalescent patients after half an year of onset on SARS-CoV-mediated cytopathic response. METHODS: SARS-CoV immunoglobulin G (IgG) antibody was determined by enzyme linked immunoadsorbent assay (ELISA). Twelve serum samples from convalescent patients, diluted by 1:8 with maintenance medium, were mixed with the three dilution supernatants of SARS-CoV. SARS-CoV were isolated, cultured and identified by the Guangzhou Institute of Respiratory Disease, and cultured with Vero E6 cell suspension. The extent of cytopathic response was observed. RESULTS: The absorbance (A) value of SARS-CoV IgG antibody ranged from 0.81 to 2.06 in patients after half an year of SARS onset, and form 0.79 to 2.01 in patients before half an year of SARS onset. The extent of cytopathic response was decreased by more than 25% in all 12 convalescent patients, as compared with control serum. CONCLUSION: The A value of SARS-CoV IgG antibody in serum of convalescent patients tended to elevate in half an year after SARS onset. SARS-CoV IgG antibody could inhibit SARS-CoV-mediated cytopathic response, indicating it might be one of protective antibodies.

Adult↗
PubMed2004

Role of individually staged nutritional support in the management of severe acute pancreatitis.

BACKGROUND: Severe acute pancreatitis (SAP) as a common acute abdomen due to complicated causes is characterized by lots of morbidities, difficult treatment, and high mortality. This study was designed to investigate the role of individually staged nutritional support (ISNS) in the treatment of SAP. METHODS: One hundred patients with SAP admitted to our hospital from January 1997 to October 2002 were randomly divided into total parenteral nutrition group (TPN group, 50 patients) and individually staged nutrition group (individualized group, 50 patients), between which the therapeutic outcome and the incidence of complications were carefully analyzed. RESULTS: Compared with the TPN group, the individualized group had less complications (62 vs 94 patients) including incubation related complications (2% vs 16%), superinfections (8% vs 30%), hepatic functional insufficiency (4% vs 24%) and intra-peritoneal infections (4% vs 12%), in addition to a sooner restoring of oral nutrition (18.5 vs 24.8 days, P<0.05), a shorter hospital stay (24.5 vs 30.2 days) and a lower hospital cost (4.1 vs 5.8 10,000 yuan, P<0.05). CONCLUSION: ISNS, which provides SAP patients with sufficient energy and nutrients according to their true pathological status, is an ideal nutrition planning with lowered incidence of complications, shortened hospital stay and lightened financial burden.

Acute Disease↗
PubMed2004

[Effects of recombinant Helicobacter pylori catalase on oxidative stress in colonic mucosal epithelial cells].

OBJECTIVE: To investigate the effects of recombinant Helicobacter pylori catalase (rHpCAT)on oxidative stress in rat colonic mucosal epithelial cells. METHODS: Oxidative stress model was established by hydroxyl generated from Fenton reaction in cultured colonic mucosal epithelial cells isolated from normal rats, in the model of which the effects of rHpCAT were observed. The cells were divided into normal control, model, 5-aminosalicylic acid (5-ASA, 0.1 mmol/L), and rHpCAT (1 x 10(5), 1 x 10(6), and 1 x 10(7) U/kg, respectively) groups. At the end of the experiment, the content of lactic dehydrogenase (LDH), malondialdehyde (MDA), myeloperoxidase (MPO), glutathione peroxidase (GSH-Px), catalase (CAT) and, superoxide dismutase (SOD) were detected in the culture supernatant. RESULTS: The contents of LDH, MDA and MPO were elevated while those of GSH-Px, CAT and SOD reduced in the model group. rHpCAT at different doses reduced the release of LDH, depressed the contents of MDA and MPO, and increased the contents of GSH-Px, SOD and CAT. CONCLUSION: rHpCAT has protective effects against rat colonic mucosal oxidative damage.

Animals↗
PubMed2004

[Experimental studies and clinical application of quickly prefabricated random skin flap].

OBJECTIVE: To enlarge the ratio of length to width of a prefabricated random skin flap in a short period, in order to meet a special clinical need. METHODS: A white rat and a white mini-pig was chosen for an animal model for the experiment. They were divided into the experimental group and the control. The prefabricated flap was formed as the planned design. In the experimental group, the flaps were treated with a desired pressure in certain intervals at the planned part of the flap. We estimated and inspected the digitized perfusion of flap microcirculation, and made overcong and wide random skin flap survive within 24 hours, and this technique was finally used for the clinical wound treatment. RESULTS: As expected, the survival area of the flap in the experimental group was significantly larger than the control. This technique was successfully used to repair the defects of the special sites in plastic and reconstructive surgery. CONCLUSION: The method of quickly prefabricated random flap could enlarge the ratio of length to width of the flap and put the flap in shape in short time. With the digitized estimating and inspecting, this method could obviously improve the survival area of the random flap and could also be very useful for the clinical treatment.

Adult↗
PubMed2004

[Capillary blood flow with dynamical change of tissue pressure caused by exterior force].

A hemodynamic model of capillary and tissue, in which tissue pressure changed with swing manipulation of Traditional Chinese Medical Massage (TCMM), is presented in this paper to explain the hemodynamic mechanism of swing manipulation. Blood flowed in capillary with low Reynolds number. Plasma exuded through capillary according to the Starling's Law. Tissue pressure changed linearly with the massage force measured. Blood apparent viscosity, plasma protein concentration and red cell's hematocrit were taken into account. Capillary flow rate, blood apparent viscosity, filtration rate and filtration fraction with dynamical change of tissue pressure were calculated numerically, and were compared with those in static tissue pressure condition. Results showed that, dynamical change of tissue pressure led to the increase of capillary flow rate and the decrease of blood apparent viscosity, which qualitatively explained the hemodynamic mechanism of "promoting blood circulation and removing blood stasis" in swing manipulation of TCMM.

Biomechanical Phenomena↗
PubMed2004

[Slow-release transdermal fentanyl used as anesthesia aided drug in ESS operation].

OBJECTIVE: To observe the safety of slow-release transdermal fentanyl (TDF) used as anesthesia aided drug in endoscopic sinus surgery (ESS) peri-operation. METHOD: In 30 cases of ESS operation, we observed their blood pressure, pulse and degree of blood oxygen saturation (SpO2%) before the TDF patch used and 10 min, 20 min, 30 min, 60 min after the patch used, their results were compared in respective. We observed the morbidity rate of patients accompanied with nausea, vomiting, bad appetite, skin reaction and vertigo at the same time. RESULT: There were no significant difference of blood pressure before and after the patch used, and so were the pulse and SpO2%. There were no patients accompanied with vomiting, vertigo and skin reaction. Four cases accompanied with nausea and bad appetite. CONCLUSION: TDF is a safe, effective and convenient anesthesia aided drug in ESS peri-operation.

Administration, Cutaneous↗
PubMed2004

[Clinical analysis of 80 cases of breast reconstruction].

OBJECTIVE: To summarize the reasons for the complications after breast reconstruction. METHODS: The reasons for the complications after breast reconstruction were analyzed in flap necrosis, abdominal wall laxity or hernia and seroma. RESULTS: The partial necrosis rate of LDF, TRAM and DIEP was 7.5%, 26% and 14.2% respectively. The total flap necrosis rate in DIEP was 7.1%. In 19 cases using breast prosthesis, the capsular contracture rate was 21%. CONCLUSIONS: The key to reduce the complications is proper selection of an operative method and the indications. The plastic surgeon should be qualified and with better comprehension of the knowledge about breast reconstruction.

Adult↗