Search PubMed⌕ Search

Biomedical subjects

S Qi

Publications and source records attributed to S Qi.

At least 55 records · Page 3Linked to original sources
PubMed1999

[Dose-effect of inhaled nitric oxide on pulmonary hypertension in inhaled injury in rabbits].

OBJECTIVE: To explore the relation of dose-response of NO inhalation in treatment of pulmonary hypertension in rabbits with smoke inhalation injury. METHODS: The effect of various concentrations (1, 5, 10, 20, 30, 40, 50 and 60) x 10(-6) of NO on pulmonary hypertension after smoke inhalation injury was studied with right heart catheterization in 15 rabbits. RESULTS: Mean pulmonary artery pressure (mPAP), pulmonary capillary wedge pressure (PCWP), pulmonary minute vessel pressure (Pmv), and pulmonary vascular resistance (PVR) were not changed remarkably (P > 0.05) after inhalation of (1 or 5) x 10(-6) NO. mPAP, PCWP, and Pmv were lowered significantly after inhalation of (10, 20, 30, 40, 50 and 60) x 10(-6) NO (P < 0.05, P < 0.01). Major vascular relaxation occurred when NO concentration was at 30 x 10(-6), and PVR did not further decrease along with the increase of NO concentration. CONCLUSION: The concentration of inhaled NO should not exceed 30 x 10(-6) for the treatment of pulmonary hypertension in early stage of smoke inhalation.

Administration, Inhalation↗
PubMed1999

[Single-catheter approach to radiofrequency current ablation of accessory pathway in Wolff-Parkinson-White syndrome with recurrent rapid atrial fibrillation].

Twelve patients with WPW were treated by single-catheter ablation. Eight patients had the histories of recurrent rapid atrial fibrillation(Af) and refractory to antiarrhythmic agents. Ventricular rate varied between 250-300 bpm. Defibrillation was needed in three patients, and one had syncope. All patients were treated successfully by ablation of accessory pathway with single-catheter approach and no Af occurred during the procedures. This result suggests that the single-catheter ablation may be an effective and feasible treatment for these patients with WPW and may be helpful in avoiding Af in multiple-catheter introducing procedure.

Adult↗
PubMed1999

[Study on combined clinical manifestation and myocardial perfusion imaging with 99mTc-MIBI SPECT for diagnosing myocarditis].

In 568 cases suffering from upper-respiratory tract infection with sore throat and more than one of following clinical manifestations: arrhythmia, heart failure and chest pain or oppressive sensation over the chest(Group A), and another 108 cases without above clinical manifestations(Group B), myocardial perfusion imaging with 99mTc-MIBI SPECT was studied. The results revealed that the imaging in 404 cases (71.12%) of Group A supported diagnosis of myocarditis, but only 6 cases(5.56%) did so in Group B. Because of lacking the clinical manifestations of myocarditis but positive finding of CVB-IgM antibody was detected in their sera, we considered that the positive SPECT imaging in these six cases of Group B belonged to myocardial reaction due to virus infection. It was possible that some of them were suffering from subclinical type of myocarditis.

Adolescent↗
PubMed1998

Synergistic effects of mycophenolate mofetil and sirolimus in prevention of acute heart, pancreas, and kidney allograft rejection and in reversal of ongoing heart allograft rejection in the rat.

BACKGROUND: The effect of mycophenolate mofetil (MMF) and sirolimus (rapamycin, RAPA) mono- and combination-therapy was examined in prevention of acute heart, pancreas, and kidney allograft rejection and in reversal of ongoing heart allograft rejection in the rat. METHODS: Both drugs were administered orally for up to 30 days. Eleven groups (n=6) were involved in the first part of the heart allografting model. Brown Norway (RT1n) to Lewis (RT1(1)) combination was used in the heart and pancreas transplantation models, whereas Buffalo (RT1b) to Wistar Furth (RT1u) was used in the kidney transplantation model. RESULTS: The naive control group showed a mean survival time of 6.5+/-0.6 days. There were graded dose-responses to monotherapy of MMF 10 and 20 mg(kg/ day (12.5+/-2.6 days; 19.3+/-9.0 days) and RAPA 0.2, 0.4, 0.8, and 1.8 mg/kg/day (19.2+/-2.0 days; 30.0+/-7.3 days; 50.8+/-12.5 days; 51.2+/-2.6 days), respectively (P=0.001). Results with the combined use of drugs indicate that a synergistic or very strong synergistic interaction was produced when compared with monotherapy of MMF or RAPA: MMF 10 mg(kg/day+RAPA 0.2 mg/kg(day (52.7+/-5.7 days, combination index [CI] =0.189), MMF 20 mg(kg/day+RAPA 0.2 mg/kg/day (57.7+/-5.7 days, CI=0.084), MMF 10 mg/kg/day+RAPA 0.4 mg(kg/day (50.2+/-13.5 days, CI=0.453), and MMF 20 mg/kg(day+ RAPA 0.4 mg/kg(day (51.5+/-6.8 days, CI=0.439), respectively. These results were repeatable in the prevention of acute pancreas and kidney allograft rejection in the rat. In the second part of the study of reversal of ongoing acute heart allograft rejection model, the combined treatment of MMF 10 mg/kg(day+RAPA 0.2 mg/ kg(day (35.5+/-16.0 days, CI=0.794) and MMF 20 mg/kg day+RAPA 0.2 mg(kg/day (57.2+/-4.7 days, CI=0.310) represented synergistic interaction compared with monotherapy of MMF or RAPA. CONCLUSIONS: Concomitant therapy of MMF and RAPA produces a synergistic effect in prevention of heart, pancreas, and kidney allograft rejection and in reversal of ongoing heart allograft rejection in the rat.

Acute Disease↗
PubMed1998

De novo-developed T cells have compromised response to existing alloantigens: using Ld-specific transgenic 2C T cells as tracers in a mouse heart transplantation model.

In this study, the phenotype, TCR signaling events, and function of T cells developed de novo during adulthood in the presence of extrathymic alloantigen were investigated. C57BL/6 mice(H-2b) were first transplanted heterotopically with BALB/c hearts (H-2d) and treated with rapamycin for 2 wk to create a tolerant status. Three weeks postoperation, the mice were whole body irradiated and transplanted with bone marrow cells from 2C mice, which are transgenic for TCR, and most of their T cells are Ld-specific CD8 cells. The 2C T cells developed de novo in the C57BL/6 mice were not able to reject the heart allograft. No clonal deletion, TCR down-regulation, or CD8 down-regulation was found in the tolerized 2C T cells. There was no characteristic phenotype of these cells in terms of CD25, ICAM-1, CD44, and MEL-14 expression. Early TCR signaling events such as intracellular calcium concentration flux, tyrosine phosphorylation, Lck and Fyn kinase activities, and Lck and Fyn protein levels in the tolerized 2C T cells were comparable to their normal counterparts, but the tolerized T cells were defective in IL-2 production and proliferation upon H-2d alloantigen stimulation in vitro. Exogenous IL-2 could not reverse the compromised proliferation. The results of this study indicate that during adulthood, the de novo-developed T cells become tolerant to extrathymic Ag without clonal deletion. These newly minted T cells are functionally defective although they are indistinguishable from normal T cells in phenotypes and in some early signaling events.

Animals↗
PubMed1998

Increased expression of the rat myometrial oxytocin receptor messenger ribonucleic acid during labor requires both mechanical and hormonal signals.

We investigated the expression of the mRNA encoding the oxytocin receptor (OTR) in rat myometrium throughout gestation and its regulation by progesterone and mechanical stretch. Using a semiquantitative reverse transcription-polymerase chain reaction approach, OTR mRNA was found to increase abruptly at the onset of spontaneous labor at term. Progesterone (4 mg/day) starting on Day 20 of gestation blocked this increase. Ovariectomy on Day 17 induced preterm labor 96 h after surgery and a significant increase in myometrial OTR mRNA levels 48 and 96 h after surgery. Both preterm labor and the rise in myometrial OTR expression were blocked by progesterone. To investigate the effects of stretch on myometrial OTR mRNA expression, unilaterally pregnant rats underwent either sham operation or placement of a tube in the nongravid uterine horn to distend the myometrium. On Day 20, stretch had no effect on OTR expression in the nongravid horns. During labor, OTR mRNA was highly expressed in the gravid horns as well as the nongravid stretched horns. In contrast, the level remained low in the nongravid unstretched horns. These results indicate that expression of rat myometrial OTR mRNA during pregnancy and labor is regulated by coordinated interactions between mechanical and endocrine signals.

Animals↗
PubMed1998

[Characteristics of radiofrequency current catheter ablation in the treatment of elderly patients with supraventricular tachycardia].

To study the effects and characteristics of radiofrequency current catheter ablation (RFCA) in treatment of elderly patients with supraventricular tachycardia (PSVT), fifty-three elderly patients and fifty non-elderly patients with PSVT were included in this study. RFCA were performed in both groups. The group of elderly patients included 26 patients with atrioventricular nodal reentrant tachycardia and 27 patients with atrioventricular reentrant tachycardia due to 29 atrioventricular accessory pathways (Aps). Twenty-one patients were accompanied with hypertension and coronary heart diseases and 5 sick sinus syndrome cases in the elderly group. All patients in both groups were treated successfully with RFCA. The procedure time of ablation of slow pathway in elderly group was shorter than that of the non-elderly group (P < 0.01). A mild symptom of arterial thrombosis was found in 2 cases of the elderly group after treatment and was cured with aspirin. These results suggest that PFCA is very effective and safe in the treatment of elderly patients with PSVT, especially for patients accompanied with sick sinus syndrome.

Aged↗
PubMed1997

Tacrolimus (FK506) and sirolimus (rapamycin) in combination are not antagonistic but produce extended graft survival in cardiac transplantation in the rat.

Combined use of tacrolimus (FK506) with sirolimus (rapamycin [RAPA]) was examined in a model of vascularized heart allograft in the rat. For prevention of acute rejection, three different combinations of low doses of FK506 and RAPA from day 1 up to day 14 after transplantation produced significantly longer cardiac allograft survival than each agent alone (P<0.05). Identical results were observed in a model of reversal of ongoing acute rejection, where two combinations of low doses of FK506 and RAPA from day 4 up to day 18 after surgery also demonstrated significantly longer graft survival than each immunosuppressant alone (P<0.05). All the low-dose-treated groups in these two models presented significantly longer heart graft survival than naive controls (P<0.05), confirming that both agents are potent immunosuppressants in the models chosen. These results also indicate that, in contrast with in vitro studies, the combined use of FK506 and RAPA in vivo did not produce antagonism, but rather had synergistic effect in prolonging the allograft survival as compared with each agent alone. It appears likely that the abundance of FKBP-12 available for binding in vivo prevents inhibitive competition of the two agents for their receptor.

Acute Disease↗
PubMed1997

Major origin of mutagenicity of chlorinated drinking water in China: humic acid or pollutants.

Since Loper and Glatz (J. Toxicol. Environ. Health, 4:919-938;1978) discovered the presence of the mutagenicity in drinking water after chlorination in 1978, humic acid (HA) has been considered as an important source. But our research results show that only 1/8 of observed direct frameshift mutagenicity in tap water originated from chlorination of HA isolated from raw water. Contamination from industrial waste and human settlement (night soil) are important potential sources of mutagenicity in chlorinated drinking water. The results show that mutagenicity from night soil after chlorination depended upon pH of sample. Production of mutagenicity at pH 6 is ten times of that at pH 8, and decomposition process is necessary condition for mutagenicity production. Season variation of mutagenicity of tap is also presented in the paper.

China↗
PubMed1997

[The changes of plasma endothelin concentration and its clinical significance in pulmonary hypertension associated with congenital heart defects].

Plasma endothelin (ET) concentration was measured by means of radioimmunoassay in 38 patients with congeital heart defects among whom 15 patients with pulmonary hypertension (PH) and 23 patients without pulmonary hypertension (non-PH). Blood samples were obtained separately from the femoral vein, right atrium, right ventricle, main pulmonary artery and the femoral artery during catherization. Plasma ET concentration in the PH group was significantly higher than that in the non-PH group at all four sampling sites. In the PH group plasma ET concentration in the pulmonary artery showed higher than that of the right ventricle and the femoral artery, which was significantly in positive correlation with pulmonary artery pressure. It is considered that the elevation of ET plays an important physiological role in the formation of pulmonary hypertension.

Adolescent↗
PubMed1997

[An experiment study of reversed pulmonary hypertension with inhaled nitric oxide on smoke inhalation injury].

We evaluated the effect and mechanisms of reversed pulmonary hypertension with inhaled nitric oxide (NO) on smoke inhalation injury in the dog model, 21 dogs were divided into 3 groups randomly. Following smoke inhalation, the control group (n = 8) inhaled O2 (FiO2, 0.45) and the treated group (n = 9) inhaled O2 and 0.0045% (45 ppm) NO. Hemodynamics was serially measured for 12 hours. In addition, 4 dogs without smoke inhalation were used to study the normal lung histomophologic findings. The data were analyzed by ANOVA. After inhalation of NO, the mean pulmonary artery pressure (mPAP), pulmonary minute vessels pressure (Pmv), and pulmonary vascular resistance (PVR) were decreased significantly (P < 0.05), while the mean aortic pressure (mAP) and total peripheral resistance (TRP) were not remarkably changed (P > 0.05). The levels of cyclic guanosine monophosphate (cGMP) were increased significantly (P < 0.01). Inhaled NO may reverse pulmonary hypertension with smoke inhalation injury in dogs. The mechanism of selective pulmonary circulation was increased cGMP level in smooth cells. Inhaled NO may be recommended for clinical application.

Administration, Inhalation↗
PubMed1997

[Study on expression of adherent proteins related to regulation of hematopoiesis in long-term cultured human bone marrow stromal cells].

OBJECTIVE: To study the molecular basis of bone marrow stromal cell supporting hematopoiesis. METHODS: Immunoelectron microscopic localization of adherent protein related to regulation of hematopoiesis was performed by immunocolloidal gold labelling technique in the adherent layer of long-term cultured human bone marrow stromal cells (LTCHBMSC). RESULTS: Adherent proteins were found to be expressed on LTCHBMSC. Double labelling revealed co-expression of these proteins and some specific markers for endothelial cells (vWF) and fibroblasts (Fb-sp). It was suggested that endothelial cells and fibroblasts in LTCHBMSC could synthesize and secrete adherent proteins, which bound to the surface of stromal cells and extracellular matrix. CONCLUSION: Adherent proteins and all kinds of hematopoietic growth factors secreted by stromal cells constitute a complex network supporting hematopoiesis.

Bone Marrow Cells↗
PubMed1997

[Radiofrequency catheter ablation of idiopathic ventricular tachycardia].

Thirteen consecutive patients with idiopathic ventricular tachycardia underwent radiofrequency catheter ablation. This group included 9 idopathic left ventricular tachycardia (ILVT) and 4 idiopathic right ventricular tachycardia (IRVT). Five ILVT patients with left axis deviation and one with right axis deviation were ablated successfully. By pace mapping, two IRVT patients with ventricular tachycardia originating from right ventricular out-flow tract were ablated. No complications occured. By means of follow-up of 3-22 months one case showed recurrence with successful reablation. It indicates that radiofrequency catheter ablation therapy is an effective and safe procedure in patients with idiopathic ventricular tachycardia.

Adolescent↗