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Shu Zhang

Publications and source records attributed to Shu Zhang.

70 records · Page 4Linked to original sources
PubMed2004

Cerebral cortical aquaporin-4 expression in brain edema following cardiac arrest in rats.

OBJECTIVES: Brain edema occurs following clinical as well as experimental cardiac arrest (CA) and predicts a poor neurologic outcome. The objective of this study was to determine the expression of cerebral cortex aquaporin (AQP)-4, a member of a family of membrane water-channel proteins, in brain edema formation following normothermic or hypothermic CA. METHODS: Twenty-four rats were subjected to time-matched normothermic (N-Sham, 37.5 degrees C +/- 0.5 degrees C, n = 6) or hypothermic (H-Sham, 34 degrees C +/- 0.5 degrees C, n = 6) sham experiments and normothermic (N-CA, n = 6) or hypothermic (H-CA, n = 6) CA induced by asphyxiation for 8 minutes. Hypothermia was induced before CA. The animals were resuscitated with cardiopulmonary resuscitation, ventilation, and epinephrine administration. Brain edema was determined by brain wet-to-dry weight ratio at one hour of resuscitation. AQP4 immunoactivity in the cerebral cortex was determined using immunohistochemical staining and was semiquantified as an intensity of staining with an automated cell imaging system. RESULTS: Mild hypothermia in the sham experiments did not alter cerebral cortex AQP4 immunoactivity (mean +/- SD) (55.0 +/- 3.7 in H-Sham vs. 53.3 +/- 1.7 in N-Sham, p > 0.05). N-CA resulted in a significant increase in AQP4 immunoactivity (61.8 +/- 4.5) compared with N-Sham (p = 0.01) and H-Sham (p = 0.03). H-CA attenuated AQP4 compared with N-CA (53.4 +/- 1.3, p = 0.01). Brain wet-to-dry weight ratios were 4.41 +/- 0.07 in N-Sham, 4.40 +/- 0.08 in H-Sham (p > 0.05 vs. N-Sham), 4.55 +/- 0.04 in N-CA (p = 0.004 vs. N-Sham; p = 0.005 vs. H-Sham), and 4.43 +/- 0.09 in H-CA (p = 0.02 vs. N-CA; p > 0.05 vs. N-Sham and H-Sham). CONCLUSIONS: Cerebral cortical AQP4 expression is up-regulated after normothermic CA, which is attenuated by hypothermia induced before CA.

Animals↗
PubMed2004

Radiofrequency catheter ablation at the left coronary cusp in treatment of repetitive monomorphic tachycardia of the left ventricular outflow tract.

BACKGROUND: The aim of this study was to clarify the electrocardiographic characteristics of repetitive monomorphic ventricular tachycardia (RMVT) originating from the left ventricular outflow tract, and to describe the results of treatment with radiofrequency catheter ablation (RFCA). METHODS: Routine 12-lead surface electrocardiography and electrophysiological studies were performed on 11 RMVT patients with no organic heart disease, who were subsequently treated with RFCA directed at targets identified by pace mapping. RESULTS: The surface electrocardiogram QRS characteristics of RMVT included an atypical left bundle branch block and right axis deviation, with a low amplitude "rs" or "rS" pattern in lead I, an "rS" or "RS" pattern in V1, and a precordial R wave transition zone in V2 or V3. In 1 patient, a small S wave was observed in V5. Using pace mapping techniques, we selected the left coronary cusp as the ablation target. RMVT was eliminated in all 11 patients immediately after radiofrequency energy delivered. During a follow-up of 13 +/- 7 months, RMVT recurred in only 1 patient. CONCLUSION: RMVT originating from the left ventricular outflow tract has specific electrocardiographic characteristics, and can be successfully and safely cured using RFCA directed at the left coronary cusp.

Adolescent↗
PubMed2004

Effects of right atrial and ventricular DDD pacing on cardiac function and ventricular contraction synchrony.

BACKGROUND: Right ventricular apical pacing has been reported to reduce cardiac performance. But there are few reports on the effects of dual chamber (DDD) pacing on cardiac function compared to sinus rhythm. In this study, we evaluated the effects of right atrial and ventricular DDD pacing on cardiac function and ventricular contraction synchrony using equilibrium radionuclide angiography. METHODS: Ten patients implanted with a right atrial and ventricular DDD pacemaker underwent equilibrium radionuclide angiography. The scintigraphic data were obtained during sinus rhythm and pacing rhythm. Cardiac function parameters were obtained semimanually. Phase analysis was used to study the ventricular activation sequence and ventricular synchrony. RESULTS: The left ventricular 1/3 ejection fraction decreased significantly during pacing compared with that during sinus rhythm [(23.4 +/- 6.1)% vs (27.7 +/- 4.5)%, P = 0.01]. Regional ejection fraction also decreased during pacing, although the difference was not statistically significant. Phase analysis showed that the right ventricle was activated earlier than the left ventricle during pacing, and that the phase shift was significantly greater during pacing than that during sinus rhythm [64.13 degrees +/- 16.80 degrees vs 52.88 degrees +/- 9.26 degrees, P = 0.007]. The activation of both ventricles occurred simultaneously during sinus rhythm, with the activation sequence from proximal septum or base of left ventricle to apex. The earliest activation during pacing occurred at the right ventricular apex, and subsequently spread to the base and left ventricle. CONCLUSION: Right atrial and ventricular DDD pacing impairs left ventricular systolic function and ventricular synchrony.

Cardiac Pacing, Artificial↗
PubMed2004

The automaticity of Mahaim fibre and its response to effective ablation.

BACKGROUND: Typical accessory pathways (APs) of Wolf-Parkinson-White syndrome have been widely discussed in recent decades. However, the characteristics of the special AP, Mahaim fibre, are not so clear. It is known that these fibres have antegrade conduction only, long conduction time, decremental node-like conduction and automaticity properties. This study was to elucidate the automaticity of Mahaim fibre and its response to effective ablation. METHODS: Thirteen patients with Mahaim fibre (ten atrioventricular and three atriofascicular accessory pathways) were subjected to electrophysiological study and radiofrequency ablation via catheter. The incidence and characteristics of anautomatic rhythm originating from Mahaim fibre were observed during the whole procedure, especially during radiofrequency current delivery. RESULTS: Repetitive and short-run automatic rhythm (rate: 65-72 beats per minute), with a QRS morphology similar to that of clinical pre-excited atrioventricular re-entrant tachycardia (AVRT), occurred in two patients during sinus rhythm. Conduction via Mahaim fibre was successfully eliminated by radiofrequency current. Fourteen applications of RF were associated with irregularly accelerated automatic tachycardia of Mahaim fibre (with a sensitivity of 78%), lasting for 1.2-14 seconds. However, such automatic tachycardia of Mahaim fibre did not occur during 54 failed applications of radiofrequency current. CONCLUSIONS: Mahaim fibre has the function of automaticity. The accelerated automatic tachycardia of Mahaim fibre occur red during radiofrequency catheter ablation can be used as a predictor for successful procedure.

Adolescent↗
PubMed2004

Effects of denitrogenation on bubble formation during decompression in rabbits.

OBJECTIVE: To explore the effect of different degrees of denitrogenation on decompression sickness. METHOD: Twenty-four rabbits were randomly divided into control group, 100% oxygen inhalation 30 min group, 60 min group and 120 min group. The rabbits were anesthetized and ventilated by mechanical ventilator. After 0, 30, 60, and 120 min of denitrogenation by inhalation of 100% oxygen, the rabbits were exposed to 11000 m for 30 min. The gas bubbles generated in the body of rabbits were detected and monitored by a Doppler ultrasound detector over the precordium. RESULT: Time to bubble appearance increased with time of 100% oxygen inhalation during altitude decompression. As compared with the control group, time to bubble appearance lengthened significantly in 100% oxygen inhalation 60 min and 120 min groups (P<0.01). Time to bubble appearance was positively correlated with time of 100% oxygen inhalation (P<0.01). Accumulative number of bubbles decreased with the time of 100% oxygen inhalation. As compared with the control group, accumulative number of bubbles decreased significantly in 100% oxygen inhalation of 60 min and 120 min groups (P<0.01). Accumulative number of bubbles was negatively correlated with time of 100% oxygen inhalation (P<0.01). CONCLUSION: Denitrogenation by inhalation of 100% oxygen for 60 min and 120 min may reduce the generation of gas bubbles in rabbits when decompressed to an altitude of 11000 m.

Animals↗
PubMed2004

[Effects of BMP-2 on the gene expression of rat osteosarcoma cells under simulated weightlessness].

OBJECTIVE: To investigate the effect of BMP-2 on (the) gene expression of rat osteosarcoma cells (ROS17/2.8) under rotating clinostat simulated weightlessness. METHOD: ROS17/2.8 cells were cultivated in 1 G control and rotating clinostat simulated weightlessness with 500 ng/ml BMP-2 in the culture medium. Total RNA in cells was isolated after 24, 48 and 72 h. Reverse transcription PCR analysis was made to examine the gene expression of alpha 1 chain of type I collagen (collagen I alpha 1) and alkaline phosphatase (ALP). RESULT: The expression of COL-I alpha 1 mRNA induced by BMP-2 was much more than that without BMP-2 in 24 h and 48 h group (P<0.01). The level of ALP mRNA induced by BMP-2 was significantly high in 48 h or 72 h group (respectively P<0.01, P<0.05). The level of BMP-2 induced expression of COL-I alpha 1 mRNA was significantly lower under 48 h of simulated weightlessness than in 1 G condition (P<0.01). The level of ALP mRNA was significantly lower under simulated weightlessness for 48 h or 72 h (P<0.01). CONCLUSION: BMP-2 can stimulate the differentiation of ROS17/2.8 cells in 1 G condition and this process is reduced under simulated weightlessness.

Alkaline Phosphatase↗
PubMed2003

Remarkable reactions of cyclooctatetraene diiron-bridging carbyne complexes with amino and amido compounds: nucleophilic addition to and breaking of the cyclooctatetraene ring.

The reactions of the cationic, diiron-bridging carbyne complexes [Fe(2)(mu-CAr)(CO)(4)(eta(8)-C(8)H(8))]BF(4) (1, Ar=C(6)H(5); 2, Ar=p-CH(3)C(6)H(4); 3, Ar=p-CF(3)C(6)H(4)) with LiN(C(6)H(5))(2) in THF at low temperature gave novel N-nucleophilic-addition products, namely, the neutral, diiron-bridging carbyne complexes [Fe(2)(mu-CAr)(CO)(4)(eta(7)-C(8)H(8)N(C(6)H(5))(2))] (4, Ar=C(6)H(5); 5, Ar=p-CH(3)C(6)H(4); 6, Ar=p-CF(3)C(6)H(4))). Cationic bridging carbyne complexes 1-3 react with (C(2)H(5))(2)NH, (iC(3)H(7))(2)NH, and (C(6)H(11))(2)NH under the same conditions with ring cleavage of the COT ligand to produce the novel diiron-bridging carbene inner salts [Fe(2)[mu-C(Ar)C(8)H(8)NR(2)](CO)(4)] (7, Ar=C(6)H(5), R=C(2)H(5); 8, Ar=p-CH(3)C(6)H(4), R=C(2)H(5); 9, Ar=p-CF(3)C(6)H(4), R=C(2)H(5); 10, Ar=C(6)H(5), R=iC(3)H(7); 11, Ar=p-CH(3)C(6)H(4), R=iC(3)H(7); 12, Ar=p-CF(3)C(6)H(4), R=iC(3)H(7); 13, Ar=C(6)H(5), R=C(6)H(11); 14, Ar=p-CH(3)C(6)H(4), R=C(6)H(11), 15, Ar=p-CF(3)C(6)H(4), R=C(6)H(11)). Piperidine reacts similarly with cationic carbyne complex 3 to afford the corresponding bridging carbene inner salt [Fe(2)[mu-C(Ar)C(8)H(8)N(CH(2))(5)](CO)(4)] (16). Compound 9 was transformed into a new diiron-bridging carbene inner salt 17, the trans isomer of 9, by heating in benzene. Unexpectedly, the reaction of C(6)H(5)NH(2) with 2 gave a novel COT iron-carbene complex [Fe(2)[=C(C(6)H(4)CH(3)-p)NHC(6)H(5)](mu-CO)(CO)(3)(eta(8)-C(8)H(8))] (18). However, the analogous reactions of 2-naphthylamine with 2 and of p-CF(3)C(6)H(4)NH(2) with 3 produce novel chelated iron-carbene complexes [Fe(2)[=C(C(6)H(4)CH(3)-p)NC(10)H(7)](CO)(4)(eta(2):eta(3):eta(2)-C(8)H(9))] (19) and [Fe(2)[=C(C(6)H(4)CF(3)-p)NC(6)H(4)CF(3)-p](CO)(4)(eta(2):eta(3):eta(2)-C(8)H(9))] (20), respectively. Compound 18 can also be transformed into the analogous chelated iron-carbene complex [Fe(2)[=C(C(6)H(4)CH(3)-p)NC(6)H(5)](CO)(4)(eta(2):eta(3):eta(2)-C(8)H(9))] (21). The structures of complexes 6, 9, 15, 17, 18, and 21 have been established by X-ray diffraction studies.

Journal Article↗
PubMed2003

Pressure-controlled ventilation attenuates lung microvascular injury in a rat model of activated charcoal aspiration.

BACKGROUND: Previous animal data suggest that aspiration of activated charcoal is associated with pulmonary microvascular injury that may be related to excessive ventilator-induced airway pressures. The purpose of this study was to test the hypothesis that ventilator-induced airway trauma contributes to the lung vascular injury observed following activated charcoal aspiration. METHODS: Capillary filtration coefficient (Kf,c), a sensitive measure of lung microvascular permeability, was determined isogravimetrically prior to and after intratracheal instillation of 0.4 ml/kg (12% weight/vol. solution, pH 7.4) activated charcoal oran equal volume of sterile water in isolated, perfused rat lungs in which ventilation was either pressure-controlled at 10cm H2O or volume-controlled at 5 ml/kg. RESULTS: There was significant lung injury in both activated charcoal groups regardless of ventilation method compared to control lungs or lungs administered sterile water (p < 0.05 ANOVA). However, injury to pressure-controlled ventilated lungs was significantly less than lungs ventilated with traditional, volume-controlled ventilation. CONCLUSION: The results of this investigation demonstrate that pressure-controlled ventilation reduces the lung microvascular injury observed following aspiration of activated charcoal as compared to traditional volume-controlled ventilation methods.

Administration, Inhalation↗
PubMed2003

Flavonoids as aryl hydrocarbon receptor agonists/antagonists: effects of structure and cell context.

Chemoprotective phytochemicals exhibit multiple activities and interact with several cellular receptors, including the aryl hydrocarbon (Ah) receptor (AhR). In this study we investigated the AhR agonist/antagonist activities of the following flavonoids: chrysin, phloretin, kaempferol, galangin, naringenin, genistein, quercetin, myricetin, luteolin, baicalein, daidzein, apigenin, and diosmin. We also investigated the AhR-dependent activities of cantharidin and emodin (in herbal extracts) in Ah-responsive MCF-7 human breast cells, HepG2 human liver cancer cells, and mouse Hepa-1 cells transiently or stably transfected with plasmids expressing a luciferase reporter gene linked to multiple copies of a consensus dioxin-responsive element. The AhR agonist activities of the compounds (1 and 10 micro M) were as high as 25% of the maximal response induced by 5 nM 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and their potencies were dependent on cell context. Galangin, genistein, daidzein, and diosmin were active only in Hepa-1 cells, and cantharidin induced activity only in human HepG2 and MCF-7 cells. Western blot analysis confirmed that baicalein and emodin also induced CYP1A1 protein in the human cancer cell lines. The AhR antagonist activities of four compounds inactive as agonists in MCF-7 and HepG2 cells (kaempferol, quercetin, myricetin, and luteolin) were also investigated. Luteolin was an AhR antagonist in both cell lines, and the inhibitory effects of the other compound were dependent on cell context. These data suggest that dietary phytochemicals exhibit substantial cell context-dependent AhR agonist as well as antagonist activities. Moreover, because phytochemicals and other AhR-active compounds in food are present in the diet at relatively high concentrations, risk assessment of dietary toxic equivalents of TCDD and related compounds should also take into account AhR agonist/antagonist activities of phytochemicals.

Animals↗
PubMed2003

[Effects of rotating clinostat simulated weightlessness on the differentiation-related gene expression of ROS17/2.8 cells].

OBJECTIVE: To investigate the effects of rotating clinostat simulated weightlessness on the differentiation-related gene expression of ROS17/2.8 (rat osteosarcoma) cells. METHOD: Cultured ROS17/2.8 cells were exposed to rotating clinostat simulated weightlessness for 24, 48 and 72 h with control group in 1 G condition. Total RNA in cells was isolated and reverse transcription PCR analysis was made. Gene expression of type I collagen alpha 1 chain and alkaline phosphatase were examined by their ratios to beta-actin. RESULT: The expression of type I collagen alpha I chain and alkaline phosphatase (ALP) gene was significantly lower after 72 h exposure to clinostat simulated weightlessness than that of the control group (P<0.01). CONCLUSION: Differentiation of rat osteosarcoma cells was reduced after exposure to rotating clinostat simulated weightlessness for 72 h.

Alkaline Phosphatase↗
PubMed2003

[Effects of microgravity on the gene expression and cellular functions of osteoblasts].

Skeleton system may adapt to multiform mechanical stimulus including gravity so as to modulate the balance between bone formation and absorption. Osteopenia under microgravity is mainly due to decrease of bone formation which relates closely to the low level of osteoblast activity. The proliferation and adhesive ability of osteoblast are reduced. The cells also express less messenger and protein of the differentiation and maturation-related substances, such as alkaline phosphatase, osteocalcin and type I collagen. The secretion of many growth factors is decreased and osteoblast responses less to them. It still remains unknown why the osteoblast is disfunctioned under microgravity. A hypothesis suggests the cellular shape changes may be the answer.

Alkaline Phosphatase↗
PubMed2003

Unipolar electrogram in identification of successful targets for radiofrequency catheter ablation of focal atrial tachycardia.

OBJECTIVE: To analyze the unipolar electrogram from successful and unsuccessful ablation sites of focal atrial tachycardia (AT), and to evaluate its value in the identification of successful targets. METHODS: Fifteen consecutive patients with focal AT were referred for radiofrequency catheter ablation (RFCA). Both unipolar (from the tip electrode of ablating catheter) and bipolar (from the distal pair of electrode of ablating catheter) electrograms were used to identify the ablation targets of focal AT. RESULTS: Successful ablation was echieved in 14 patients. Radiofrequency energy was delivered at a total of 27 sites. The bipolar electrograms associated with successful ablation sites showed earlier atrial deflection relative to P wave onset (36 ms +/- 15 ms vs 30 ms +/- 11 ms, P < 0.05) than the electrograms associated with failed ablation sites. At the 14 successful ablation sites, the unipolar electrograms displayed a completely negative atrial wave ("QS" morphology) beginning with intrinsic deflection. However, at the 13 unsuccessful ablation sites, a "rS" morphology of atrial wave was shown on the unipolar electrogram. CONCLUSION: The "QS" morphology of the atrial wave on unipolar electrograms appears to represent a reliable marker for identifying the successful ablation targets of focal AT, with a high sensitivity and specificity.

Adolescent↗
PubMed2003

[The modified isolation and culture method of rat Sertoli cells].

OBJECTIVE: To simplify the procedures of isolation of rat Sertoli cells and increase the yield of Sertoli cells cultured. METHODS: Decapsulated rat testis from 16-22-day-old SD rats were digested by sequential two-step digestion using 0.25% pancreatin, 0.05% collagenase in order, and then the cell suspension was cultured in incubator under the condition of 37 degrees C and 5% CO2 for 48 h. The yields were observed and Fas Ligand (Fas-L) was tested by immunohistochemical method. RESULTS: By the use of this modified method, the yielded sertoli cells accounted for 90% of all the cells harvested. High level expression of Fas-L was detected. CONCLUSION: This modified method increases the yield of Sertoli cells and the procedures of isolation and culture are greatly simplified.

Animals↗
PubMed2002

Mild hypothermia induced before cardiac arrest reduces brain edema formation in rats.

OBJECTIVES: The mechanisms by which hypothermia improves cardiac arrest (CA)-induced brain damage are unclear. The authors hypothesized that mild hypothermia induced before CA attenuates brain edema formation by preventing neutrophil-mediated dysfunction of the endothelial cell junction proteins. METHODS: Eighteen rats were randomized to normal control surgery (group 1, n = 6), normothermic (37.5 degrees C) CA (group 2, n = 6), or hypothermic (34 degrees C) CA (group 3, n = 6). Hypothermia was induced with external cooling before CA in group 3. Cardiac arrest was induced by 8 minutes of asphyxiation. Brain edema was determined by wet-to-dry weight ratio and cerebral spinal fluid pressure (CSFP). Brain neutrophil content was determined by myeloperoxidase (MPO) activity, and occludin degradation was assessed by western blotting. RESULTS: Normothermic CA significantly increased brain wet-to-dry weight ratio from 4.52 +/- 0.04 in group 1 to 4.80 +/- 0.04 in group 2 (p = 0.0003) and CSFP from 3.6 +/- 0.9 in group 1 to 8.9 +/- 0.9 mm Hg in group 2 (p = 0.004). Mild hypothermia before CA in group 3 significantly reduced brain wet-to-dry weight ratio (4.68 +/- 0.03, p = 0.008 vs. group 2) and CSFP (3.8 +/- 0.5 mm Hg, p = 0.004 vs. group 2). Cardiac arrest increased brain MPO from 0.07 +/- 0.025 in group 1 to 0.16 +/- 0.02 units/gram brain weight in group 2 (p = 0.006) that was not decreased by hypothermia before CA (0.12 +/- 0.02 in group 3 (p = 0.07 vs. group 2). There was no occludin proteolysis in any group. CONCLUSIONS: Mild hypothermia before CA decreases CA-induced brain edema. The hypothermia-elicited reduction in brain edema does not appear to be neutrophil-dependent and the early brain edema formation may not involve the proteolysis of occludin.

Analysis of Variance↗
PubMed2002

[Effects of simulated weightlessness on the expression of cyclooxygenase-2 in rat calvarial osteoblasts induced by fluid shear stress].

OBJECTIVE: To investigate the effect of simulated weightlessness on mechanotransduction in rat calvarial osteoblasts. METHOD: Osteoblasts were isolated from neonatal rat calvariae and then were set to two groups. One was cultured in clinostat to simulate the weightlessness environment. Another was cultured in 1 G gravitational environment. After 60 h, osteoblasts were treated with 0.5 Pa or 1.5 Pa FSS in a flow chamber. The FSS treatment time was set to 30 min and 60 min, respectively. The specimens of each group were obtained for immunohistochemistry staining and determination of expressions of cyclooxygenase-2 (COX-2) in osteoblasts. RESULT: In osteoblasts cultured in 1 G gravitational environment, COX-2 expression was increased remarkably from 30 min to 60 min with the treatment of FSS (P<0.01). There was no clear difference between the expression of COX-2 after treatments of 0.5 Pa or 1.5 Pa FSS; In cells cultured in simulated weightlessness environment, no detectable expression of COX-2 was found with the treatment of 0.5 Pa FSS. The expression of COX-2 was only detected after 60 min treatment of 1.5 Pa FSS, but the level of expression was decreased significantly (P<0.01). CONCLUSION: These results demonstrated that the mechanotransduction in osteoblasts was down-regulated in simulated (correction of stimulated) weightlessness.

Animals↗