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Biomedical subjects

M Z Jiang

Publications and source records attributed to M Z Jiang.

6 recordsLinked to original sources
PubMed2000

Role of nitric oxide in human pulmonary microvascular endothelial cell adhesion.

We examined the effect of nitric oxide (NO) on cell adhesion using cultured human pulmonary microvascular endothelial cells (PMVEC). Attachment of these cells to fibronectin was significantly inhibited by NO donors, spermine NONOate and S-nitroso-N-acetyl-penicillamine or L-arginine, but not 8-bromoguanosine-3',5'-cyclic-monophosphate. Similar results were obtained with the electrical cell-substrate impedance sensor (ECIS) technique. Addition of NO donors or L-arginine, but not 8-bromoguanosine-3',5'-cyclic-monophosphate or N2,2'-O-dibutyrylguanosine-3',5'-cyclic-monophosphate, to confluent PMVEC monolayers resulted in a transient decrease in cell adhesion, which was quantitated by the ECIS. Exposure to 1 U/ml alpha-thrombin reduced the monolayer electrical resistance by approximately 50%. The observed response was significantly suppressed by pretreatment of cells with intracellular calcium chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid or NO synthase inhibitor, N(G)-nitro-L-arginine methyl ester, but not guanylate cyclase inhibitor, 6-anilino-5,8-quinoline-quinone. Selective knockout of endothelial NO synthase with antisense oligodeoxynucleotides also significantly reduced thrombin-induced decrease in monolayer resistance. Our findings indicate that thrombin stimulates calcium-dependent release of NO from PMVEC, which mediates the retraction of endothelial cells via a cGMP-independent pathway. Our results suggest that NO modulates cell-matrix and/or cell-cell adhesion in PMVEC and that this molecule might modify microvascular permeability in the human lung.

Capillary Permeability↗
PubMed2000

Increased oxidative stress in rats with chronic nitric oxide depletion: measurement of urinary 8-hydroxy-2'-deoxyguanosine excretion.

Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) has been reported to serve as a sensitive biomarker of oxidative stress. We examined the effect of chronic blockade of nitric oxide (NO) on urinary excretion of 8-OHdG in rats. Two types of NO synthase inhibitor were used: N(G)-nitro-L-arginine methyl ester (L-NAME) as a non-selective inhibitor and aminoguanidine (AG) as a selective inhibitor of the inducible isoform. Oral administration of L-NAME (20, 50 and 80 mg/dl of drinking water), but not AG (400 mg/dl), for 4 weeks induced systemic hypertension and a significant reduction in urinary excretion of NO2-/NO3-. Rats treated with L-NAME also showed a significant increase in urinary 8-OHdG excretion compared with the control animals. The effects of L-NAME (50 mg/dl) on blood pressure and urinary excretion of NO2/NO3- and 8-OHdG were restored by a large dose of L-arginine (2.0 g/dl). Chronic AG administration did not significantly alter urinary 8-OHdG excretion. On combining all the data, there was a significant negative correlation between urinary NO2-/NO,- and 8-OHdG. These observations suggest the importance of constitutive NO synthase activity in the maintenance of oxidant buffering capacity in rats. Oral administration of L-NAME may serve as a model of hypertension due to chronic NO deficiency with increased oxidative stress.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1995

Developing interactive computer-based simulations: an object-oriented development methodology enhances computer-assisted instruction.

The purpose of this research was to investigate the application of object-oriented technology and AI techniques to enhance development of computer-based training simulations. Towards that end, a comprehensive computer-assisted instructional unit was developed to teach the skills and concepts of window-based applications, the OS/2 desktop, and the use of a patient care information system. By taking advantage of sophisticated computer graphics for the visual representation of objects and the behavioral modeling capabilities of the object-oriented language, domain knowledge modeling and human-computer interactions were implemented without complex natural language processing techniques. The results of this research indicate that nurses and physicians are able to learn the basic skills and concepts of computer systems and how to query for patient information. The new methodology described for building these computer-assisted instructional simulations significantly eased the training and teaching of large numbers of nurses and physicians and simplified their transition to a complex, computer-based hospital information system environment.

Computer Graphics↗
PubMed1994

[Effects of lidocaine on contraction of isolated rabbit aortic rings].

The mechanism of relaxing effects of lidocaine (Lid) on the contraction of isolated rabbit thoracic aortic rings was studied. Verapamil (Ver) was used for comparison. Lid and Ver showed obvious relaxing effect on contraction evoked by high K+ depolarization. In the study of contractions induced by noradrenaline (NA), both Lid and Ver were shown to suppress the component elicited by calcium release from the intra-cellular store, but not that induced by calcium influx. Lid shifted the dose-response curves for KCl and NA to the right nonparallelly and depressed their maximal responses. The inhibition to KCl was more potent than that to NA. This suggests that Lid has selective blocking effects on PDC channel, but not the ROC channel. Lid shifted the dose-response curve for CaCl2 to the right nonparallelly and depressed its maximal response. The results indicate that the calcium antagonistic property of Lid may be one of the mechanisms of its vascular smooth muscle relaxing effect.

Animals↗