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Biomedical subjects

X Deng

Publications and source records attributed to X Deng.

At least 181 records · Page 10Linked to original sources
PubMed1994

Monoclonal antibody to murine PECAM-1 (CD31) blocks acute inflammation in vivo.

A murine model of peritonitis was used to test the role of platelet/endothelial cell adhesion molecule 1 (PECAM-1/CD31) in acute inflammation. A monoclonal antibody (mAb) specific for murine PECAM-1 injected intravenously 4 h before the intraperitoneal injection of thioglycollate broth blocked leukocyte emigration into the peritoneal cavity for up to 48 h. This block was particularly evident for neutrophils. Control mAb, including one that bound to murine CD18 without blocking its function, failed to block emigration when used at the same or higher concentrations. The decreased emigration seen with the anti-PECAM-1 antibody was not due to neutropenia or neutrophil sequestration in the lung, spleen, or other organs; peripheral blood leukocyte counts were not diminished in these mice. In the mesenteric venules of the mice treated with anti-PECAM-1 mAb, leukocytes were frequently seen in association with the luminal surface of the vessel, but did not appear to emigrate. Thus, the requirement for PECAM-1 in the transendothelial migration of leukocytes previously seen in an in vitro model holds true in this in vivo model of acute inflammation.

Animals↗
PubMed1994

Renal vasoconstriction during inhibition of NO synthase: effects of dietary salt.

Since dietary salt loading enhances nitric oxide (NO) generation in the kidney, we investigated the hypothesis that changes in salt intake have specific effects on vascular resistance in the kidney mediated by the L-arginine-NO pathway. We contrasted changes in renal and hindquarter vascular resistances (RVR and HQVR) in anesthetized rats during intravenous infusions of graded doses of the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME). Groups (N = 8 to 10) of rats were maintained on a high salt (HS) or low salt (LS) diet for two weeks. Compared to those on LS, rats on HS had a greater increase in mean arterial pressure (delta MAP; +32 +/- 4 vs. +22 +/- 3%; P = 0.05) and RVR (+160 +/- 17 vs. +83 +/- 10%; P < 0.005) and a greater fall in renal blood flow (delta RBF; -47 +/- 3 vs. -32 +/- 4%; P < 0.01); changes in HQVR were similar in the two groups. The enhanced RVR response to L-NAME in HS rats could not be ascribed to the higher renal perfusion pressure (RPP) since it persisted in rats whose RPP was controlled by adjustment of a suprarenal aortic clamp. Changes in RVR with an NO donor (SIN-1) were similar in HS and LS rats. L-NAME reduced plasma renin activity in both HS and LS rats. After inhibition of ACE with captopril, or of angiotensin II type I (AT1) receptor with losartan, the increase in RVR with L-NAME remained greater in HS than LS rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Oxidoreductases↗
PubMed1994

Biomechanical evaluation of a simulated Bankart lesion.

The purpose of this study was to determine the effect of sectioning of the anterior part of the inferior glenohumeral ligament (a simulated Bankart lesion) on load-induced multidirectional glenohumeral motion. Nine fresh, intact cadaveric shoulders were tested on a special apparatus that constrained three rotations but allowed simultaneous measurement of anterior-posterior, superior-inferior, and medial-lateral translation. Coupled anterior-posterior and superior-posterior translations were recorded while anterior, posterior, superior, and inferior forces of fifty newtons were applied sequentially. Testing was done in three positions of humeral elevation in the scapular plane, in three positions of humeral rotation, and with an externally applied joint-compression load of twenty-two newtons. A liquid-metal strain-gauge was placed on the posterior band of the inferior glenohumeral ligament to assess concomitant posterior capsular strain during the various test conditions. All shoulders were tested intact and again after the inferior glenohumeral ligament and the labrum had been detached from the glenoid from just superior to the anterior band of the inferior glenohumeral ligament to a point just posterior to the infraglenoid tubercle. The simulated Bankart lesion resulted in selected increases in anterior translation at all positions of elevation, in posterior translation at 90 degrees of elevation, and in inferior translation at all positions of elevation. However, these increases were very small; the maximum mean increase in translation seen over-all was only 3.4 millimeters, which occurred during inferior translation at 45 degrees of elevation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

[The effect of Baji Zibugao on the serum levels of endocrines in thyroidectomized (yang deficiency) rabbits].

In order to study the effect of Baji Zibugao (BJZBG, a medicinal plaster mainly consisting of Radix Morindae Officinalis) on the endocrine functions of hypothyroid rabbits, we determined the serum levels of thyroxine (T4), triiodothyronine (T3), cAMP, cGMP and corticosterone in three groups of rabbits: total thyroidectomized and untreated (group I), total thyroidectomized and treated with BJZBG (group II) and controls (group III). The results showed: (1) The serum level of T4 in group I and II after operation was significantly lower than that before operation (P < 0.005), and the serum level of T3 in group I was also lower than that before operation (P < 0.02), but the change of T3 in group II after operation was not significant (P > 0.05); (2) The serum cAMP level in group I after operation decreased and the cGMP level increased (P < 0.025), but the changes of cAMP and cGMP level in group II after operation were not significant (P > 0.05), (3) The change of serum corticosterone level in group I or II after operation was not remarkable (P > 0.05).

Animals↗
PubMed1994

[The phenotypic change of smooth muscle cells in the media of pulmonary intra-acinar arteries during hypoxia].

The phenotypic change of smooth muscle cells (SMCs) in the media of pulmonary intraacinar arteries (IAA) was observed in rats during hypoxia. From 3 to 40 exposure days, pulmonary arterial pressure (PAP) and right ventricular hypertrophy increased parallely. From 1 to 5 exposure days, SMCs still displayed the "contractile" phenotype, but the amount of intercellular collagen slightly increased. After 7 exposure days, some medial SMCs changed into the "fully" or "partially" "synthetic" phenotype with an excess of intercellular collagen. From 14 to 40 exposure days, other than some SMCs of partially "synthetic" phenotype, a great number of SMCs acquired the "contractile" phenotype characteristics, but the synthetic and secretive organelles and intercellular collagen were still more than those in the groups from 1 to 5 exposure days. Our results suggested that along with the prolongation of hypoxic exposure, the kinetic changes of SMC phenotype might not parallel with PAP change.

Animals↗
PubMed1993

PECAM-1 is required for transendothelial migration of leukocytes.

Platelet/endothelial cell adhesion molecule 1 (PECAM-1; CD31) is crucial to the process of leukocyte transmigration through intercellular junctions of vascular endothelial cells. A monoclonal antibody to PECAM, or recombinant soluble PECAM, blocks transendothelial migration of monocytes by 70-90%. Pretreating either the monocytes or the endothelial junctions with antibody blocks transmigration. If the endothelium is first activated by cytokines, anti-PECAM antibody or soluble recombinant PECAM again block transmigration of both monocytes and neutrophils. Anti-PECAM does not block chemotaxis of either cell type. Light and electron microscopy reveal that leukocytes blocked in transmigration remain tightly bound to the apical surface of the endothelial cell, precisely over the intercellular junction. Thus, the process of leukocyte emigration can be dissected into three successive stages: rolling, mediated by the selectin class of adhesion molecules; tight adhesion, mediated by the leukocyte integrins and their endothelial cell counter-receptors; and now transmigration, which, based on these studies, requires PECAM-1.

Antibodies, Monoclonal↗
PubMed1993

Nitric oxide mediates renal vasodilation during erythropoietin-induced polycythemia.

The renal blood flow (RBF) of patients with polycythemia rubra vera is increased despite the high hematocrit (Hct) which elevates the whole blood viscosity. Since blood viscosity determines the shear force on the endothelium which is a major stimulus to nitric oxide (NO) release, we investigated the hypothesis that renal vasodilation during erythropoietin-induced erythrocytosis is mediated by the L-arginine-NO pathway. Groups of Sprague-Dawley rats received thrice weekly injections of erythropoietin (E) for two to five weeks; responses were contrasted with normal rats (N) which received sham injections. The first group was studied after five weeks of erythropoietin injections which led to sharp increases in Hct (E: 72 +/- 3 vs. N: 44 +/- 1%) and mean arterial pressure (MAP: 126 +/- 3 vs. 107 +/- 3 mm Hg). These rats had an elevated basal RBF whether measured by the clearance and renal extraction of PAH or by a transit-time renal blood flow meter. Subsequent groups were studied after two to three weeks of erythropoietin which raised the Hct more modestly to 59 +/- 2%. In this group, the basal MAP was similar in E and N rats. Graded doses of the NO synthase inhibitor, N omega-monomethyl-L-arginine (L-NMA) led to a steeper rise in MAP in E than N; at the highest doses, the MAP had increased by 36 +/- 2 in E and 23 +/- 3 mm Hg in N (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

The hypoxic moderation of systemic hypertension in spontaneously hypertensive rats.

The mechanism of hypoxic moderation of systemic systolic blood pressure was investigated in spontaneously hypertensive rats (SHR). Male SHR rats were divided into hypoxic (H, 5000 m for 15 d) and normoxic (N) groups. The systemic blood pressure of SHR-H (24.9 +/- 1.2 kPa) was found to be 3 kPa lower than that in SHR-N (27.0 +/- 1.3 kPa) (P < 0.05). This protective effect may have been related to the adaptive changes in vascular reactivity which manifested as an increase in the relaxation response of the aorta to ACh (P < 0.01) and a drop in its contraction in response to 5-HT (P < 0.05) following hypoxic exposure. The hypoxic moderating effect against the development of systemic hypertension may have also been related to the increased plasma levels of ANP observed.

Altitude↗
PubMed1993

[Changes in TXB2/6-keto-PGF1 alpha ratio and their relation to blood lipids of Type A behavioral patterns].

To study the pathophysiological relation between Type A behavioral pattern and coronary artery disease, we analyzed the Type A behavioral pattern, serum triglycerides (TG), cholesterol (TC), high density lipoprotein cholesterol (HDLc), and TXB2, 6-keto-PGF1 alpha in 60 patients with coronary artery disease and 60 age-sex-matched healthy subjects. All of them had normal blood pressure. The results showed Type A behavioral pattern was more prevalent than Type B behavioral pattern in coronary artery diseased patients and the reverse was true in the controlled subjects (P < 0.025); TG, TC and TXB2/6-keto-PGF1 alpha ratio increased significantly in Type A behavioral pattern compared with Type B behavioral patients, but HDLc/(TC+TG) and the level of HDLc decreased significantly in the Type A behavioral pattern than in the Type B behavioral pattern (P < 0.05). The TG, TC increased significantly and 6-keto-PGF1 alpha HDLc decreased significantly in the coronary artery diseased patients (P < 0.05). However, the ratio of TXB2/6-keto-PGF1 alpha was inversely related to HDLc/(TC+TG) among the coronary artery diseased patients. The results of this cross-sectional study suggest that coronary artery disease is associated with Type A behavioral pattern through the metabolism of lipids and prostaglandins in various ways.

6-Ketoprostaglandin F1 alpha↗
PubMed1993

Interspecific somatic hybrid of Ichang papeda with Valencia orange.

Protoplasts from the leaf of Ichang papeda (Citrus ichangensis Swingle) were fused with the protoplasts of embryogenic suspension culture of Valencia orange (Citrus sinensis Osbeck) in vitro by polyethylene glycol (PEG)-induced fusion. The regenerated embryoids were malformed and were transferred onto shoot induction medium. The shoots were then grafted on 15-day-old seedlings of trifoliate orange in vitro. Chromosome counts of the young leaves showed that the parents were diploids, 2n = 2x = 18, and the regenerated plants were tetraploids, 2n = 4x = 36. Peroxidase and glutamate oxaloacetate transaminase isozyme analysis confirmed that these tetraploids were somatic hybrids. They have the bands of both parents. The hybrid plants grew vigorously after transplanted into soil. Leaf morphology of the hybrid was similar to that of sweet orange.

Cells, Cultured↗
PubMed1990

[Primary study on pathogenesis of Campylobacter jejuni enteritis].

The invasiveness and heat-labile enterotoxin of 11 human strains of C. jejuni were detected in NIH mice inoculated with the C. jejuni strains; the methods of plate immunological hemolysin test and SPA-coagglutination test were employed. Ten strains of the bacteria invaded the intestine; 7 strains (45.46%) were positive in SPA-coagglutination test; and 4 (36.36%) produced enterotoxin. C. jejuni in Chengdu area possess multiple pathogenicity, e.g invasiveness and heat-labile enterotoxin, but we did not find definitive correlations between the clinical manifestation and resource of strains.

Animals↗
PubMed1990

[Experimental study of hypoxic pulmonary hypertension].

The dynamic changes in pulmonary vascular tone and reactivity of rats exposed to chronic hypobaric hypoxia were studied with cardiac catheterization and on perfusing isolated lung-preparations. It was found that their greatest rising appeared earlier than that of the pulmonary arterial pressure, and improving heart function might delay the development of hypoxic pulmonary hypertension. Whenever hypoxia was slight in extent, a compensatory increase in cardiac function was seen on the right side with no change in left heart. When hypoxia became more severe, an impairment of heart function occurred predominantly on the left side with or without decrease in the function of the right heart.

Animals↗
PubMed1990

[Inhibitory effect of yunfujing on vestibular stimulative response in rats and volunteers].

Fifty female rats were used in the experiment. With rotation model, Yunfujing was shown to inhibit nystagmic response of rats. The inhibitory effect was 20-30 times stronger than that of Mihuanjun. In Coriolis test, the tolerance time of vestibular stimulative response was taken as a parameter for judging drug efficacy in 32 male volunteers. Following oral administration of Yunfujing at a dose of 400 mg, the tolerance time of vestibular stimulative response was prolonged significantly from 411.34 to 759.63 s. In the mean time, no changes of blood pressure and pulse were observed in the treated group.

Adolescent↗
PubMed1990

[Observation of efficacy of different dialytic therapies in renal transplantation preparation].

Fifty-seven cadaveric renal transplantations in fifty-five cases were analysed of them, thirty cases were prepared by continuous ambulatory peritoneal dialysis (CAPD group); twenty-seven transplantations in twenty-five cases were prepared by hemodialysis (HD group). Our data show that there is no significant difference in the survival duration between CAPD group and HD group; that there is also no significant difference in the survival duration between the two groups treated with the same immunosuppressive drugs, and that patients prepared by CAPD have a low risk of peritonitis after transplantation. It is better not to remove the Tenckhoff catheter until the graft function is stable so that it can be used for the transient peritoneal dialysis in the case of the insult of graft function or for the sampling of the peritoneal effusion for diagnosis of suspectable peritonitis after renal transplantation.

Adult↗
PubMedDate not supplied

Low Reynolds number turbulence modeling of blood flow in arterial stenoses.

Moderate and severe arterial stenoses can produce highly disturbed flow regions with transitional and or turbulent flow characteristics. Neither laminar flow modeling nor standard two-equation models such as the kappa-epsilon turbulence ones are suitable for this kind of blood flow. In order to analyze the transitional or turbulent flow distal to an arterial stenosis, authors of this study have used the Wilcox low-Re turbulence model. Flow simulations were carried out on stenoses with 50, 75 and 86% reductions in cross-sectional area over a range of physiologically relevant Reynolds numbers. The results obtained with this low-Re turbulence model were compared with experimental measurements and with the results obtained by the standard kappa-epsilon model in terms of velocity profile, vortex length, wall shear stress, wall static pressure, and turbulence intensity. The comparisons show that results predicted by the low-Re model are in good agreement with the experimental measurements. This model accurately predicts the critical Reynolds number at which blood flow becomes transitional or turbulent distal an arterial stenosis. Most interestingly, over the Re range of laminar flow, the vortex length calculated with the low-Re model also closely matches the vortex length predicted by laminar flow modeling. In conclusion, the study strongly suggests that the proposed model is suitable for blood flow studies in certain areas of the arterial tree where both laminar and transitional/turbulent flows coexist.

Arteries↗
PubMedDate not supplied

Gene expression and gene therapy in experimental duodenal ulceration.

Gastroduodenal ulceration is still poorly understood and changes in gene expression may provide new mechanistic insights. Previously, we demonstrated that angiogenic growth factors are potent ulcer healing agents, and the synthesis of bFGF, PDGF and VEGF is enhanced early in duodenal ulcer healing. The initial molecular event in duodenal ulceration seems to be the organ-specific early release of ET-1 in the pre-ulcerogenic stages after the administration of duodenal ulcerogen cysteamine in rats. We also briefly review here data from literature indicating a central role of ET-1 in gastroduodenal ulceration. After studying the involvement of immediate early genes (e.g. egr-1, Sp1) in ulcer development, we now investigated expression of other genes in the duodenal mucosa in the early stages of chemically induced duodenal ulceration in rats. Following a brief review of principles of gene expression and gene therapy, we review our preliminary gene expression studies, involving monitoring about 1200 genes which revealed about 160 signals and prominent changes in about 30 genes in the early stages of experimental duodenal ulceration. Cysteamine enhanced ET-B receptor gene expression in 30 min, while transcription factors (MAX, STAT 3) showed increased expression in 12 h. We recently also initiated gene therapy studies to enhance the local synthesis of PDGF and VEGF to accelerate duodenal ulcer healing, using a single dose of naked DNA (ND) or adenoviral (AV) vectors of VEGF and PDGF in rats with cysteamine-induced duodenal ulcers. Gene therapy with ND or AV of VEGF or PDGF significantly accelerated chronic duodenal ulcer healing, and increased levels of VEGF and PDGF were detected by Western blotting and ELISA in duodenal mucosa after both VEGF and PDGF gene therapy. Thus, gene expression studies provide new insights into the molecular mechanisms of duodenal ulceration and VEGF or PDGF gene therapy seems to be a new option to achieve a rapid ulcer healing.

Animals↗