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Biomedical subjects

R Xiu

Publications and source records attributed to R Xiu.

11 recordsLinked to original sources
PubMed2000

Microvascular medicine in Asia.

The frontiers of microcirculatory research in the present world is reviewed in relation to the development of genomics and post-genomics.

Asia↗
PubMed2000

The therapeutic effect of Ginkgo biloba extract in SHR rats and its possible mechanisms based on cerebral microvascular flow and vasomotion.

This paper aimed to investigate the therapeutic effect of an extract of Ginkgo biloba leaves (EGb 761) on hypertension and its possible mechanisms in the view of cerebral microcirculation. Twenty normotensive rats and 24 SHR rats were used. Surgical preparation was made to produce a cranial window for observation of the capillary network on the cerebral cortex. The intravital videomicroscopy equipped with digital image processing system and laser Doppler flowmeter were used for this study. The arterial blood pressure, red cell velocity (V), microvacular diameter (D), number of open capillaries (OCN), circulating endothelial cells (CEC) in blood, relative blood flow (Flow) and frequency (Fc), amplitude (AMP) of vasomotion were measured. The obtained data were compared between EGb-treated rats that received per os 100 mg/kg/d for 9 days and placebo control rats. Untreated SHR rats showed very severe dysfunction in the microcirculation with high blood pressure (213 +/- 16.7 mmHg). The blood pressure decreased significantly to 153 +/- 20 mmHg in EGb-treated SHRs group, compared with those of untreated rats (p < 0.01). Both normotensive and hypertensive rats increased the blood flow velocity and LDF flow after EGb-treatment. The vasomotion property, the CEC and OCN changed greatly in EGb-treated SHR rats, but no significant difference was observed in normotensive rats. It was suggested that EGb 761 had therapeutic effect on SHR rats by increasing blood perfusion, regulating vasomotion function, opening efficiently capillaries and releasing the peripheral resistance. The injured vascular endothelium of SHR rats was also partly reversed by EGb-treatment. It was concluded that EGb 761 could be used to regulate hypertension and to protect the cerebral microcirculatory function.

Animals↗
PubMed2000

Anticancer treatment of endostatin gene therapy by targeting tumor neovasculature in C57/BL mice.

Antiangiogenesis strategy has been widely recognized as a viable approach to fight cancer. Considering the high cost and inconvenience of protein therapy of endostatin (ES), which is a potent antiangiogenic protein, we attempted to explore the inhibitory effect of ES gene therapy on tumor growth and metastasis. In this experiment, Lewis lung carcinoma (LLC)-bearing C57/BL mice were used to evaluate the antitumor effect of ES gene therapy and its impairment of tumor neovasculature. The data showed that the ectopic ES in circulation expressed by intramuscular administration of formulated ES-encoding plasmid DNA significantly suppressed primary tumor growth and lung metastasis in LLC-bearing C57/BL mice. Hence, our results demonstrated the inhibitory effect of ES gene therapy on angiogenesis-dependent tumor growth and metastasis.

Angiogenesis Inhibitors↗
PubMed2000

Gene transfer of vascular endothelial growth factor plasmid/liposome complexes in glioma cells in vitro: the implication for the treatment of cerebral ischemic diseases.

Vascular endothelial growth factor (VEGF) is most promising in therapeutic angiogenesis for ischemic vascular disease. This paper aimed to study VEGF gene therapy for the treatment of cerebral ischemia. The glial cell was chosen as the target cell for gene transfer, and the expression of VEGF was studied in vitro. VEGF plasmid/liposome complexes were constructed by mixing VEGF plasmid with liposome, and then cultured C6 glioma cells were transfected with these complexes by lipofectamine method. As control, the same kind of cells were exposed to liposome only. Immunohistochemistry was performed to both groups at 24, 48 and 72 hours after transfection. The transfected cells expressed VEGF significantly higher than the control. The present result demonstrated the feasibility of choosing the glial cell as the target cell for VEGF gene transfer, and found the rationale for the cerebral VEGF gene therapy.

Animals↗
PubMed2000

The role of the microlymphatic valve in the propagation of spontaneous rhythmical lymphatic motion in rat.

Male Wistar rats (n = 12) with the mesenteric preparation were used to quantitatively investigate the characteristics of wave-like propagation of spontaneous rhythmical lymphatic motion and to explore the mechanism of microlymphatic valve on the activity of lymphatic motion. The dynamical behaviors of collecting lymphatics were visualized by a closed circuit TV system. The frequency, amplitude, and phase angle of the diameter oscillation, the spreading speed of peristaltic wave and the contractile index (CI) of rhythmical lymphatic motion were measured and calculated by the image processing system. The lymphatic segment between two adjacent valves, named by lymphangion, was a basic unit of microlymphatic activity. The present results revealed that there was a wave-like propelling of the contractile activity progressively from one lymphangion to the next. No significant characteristic differences were observed from the two adjacent lymphangion units except the increasing contractile index. The motion wave propagation from upstream over a valve to down stream led to a significant phase angle change. The pacemaker site of lymphatic motion seemed to be at the inlet side of the valve in each lymphangion unit. The contractile motion wave propagated just within each lymphangion unit. The lymph flow over the valve converted the pressure changes between two adjacent lymphangions and stimulated a new contraction wave at the next inlet site of valve. The endothelium response to wall tension and shear stress alteration near the inlet valve site might be one of the pacemaking mechanisms of lymphatic motion.

Animals↗
PubMed1997

[Elimination of cholesterol in human endothelial cells].

OBJECTIVE: To investigate what role the endothelial cell interfacing with blood components to play in cholesterol metabolism. METHODS: Isotopelabeling technique, Gas Chromatography/Mass Spectrometry and Western blotting were used to measure the presence of 27-oxygenated cholesterol in medium and the presence of sterol 27-hydroxylase in endothelium. RESULTS: When human endothelial cells were cultured in a medium containing fetal calf serum, there was a significant accumulation of 27-hydroxycholesterol and 3 beta-hydroxy-5-cholesteneic acid, products of cholesterol metabolism, in the medium. The rate of formation of these products almost increased linearly with time of cultivation. After addition of 100 micrograms of extraneous cholesterol to the medium, the accumulation of 27-hydroxy-cholesterol and 3 beta-hydroxy-5-cholesteneic acid increased significantly. Addition of more cholesterol did not further increase the formation of 27-hydroxy-cholesterol and caused a decrease in the formation of 3 beta-hydroxy-5 cholesteneic acid. The presence of sterol-27-hydroxylase in the endothelium was demonstrated by Western blotting. CONCLUSION: Cultured human endothelium from umbilical veins are able to convert exogenous cholesterol into 27-hydroxy-cholesterol and 3 beta-hydroxy-5-cholesteneic acid. Furthermore, the cells are able to transport these products from the cells into the medium.

Cells, Cultured↗
PubMed1995

[The characteristics of spontaneous rhythmical microlymphomotion].

It is now generally accepted that the spontaneous contraction of lymph vessel contributes to fluid and protein transportation from the interstitial back to bloodstream. In this study, 20 male Wistar rats with the preparation of mesentery were divided into three groups: valve group (6), control group (7), and 654-2 group (7). We studied the mechanism of valve on rhythmical microlymphomotion and the effect of 654-2, a vasoactive substance, on lymphatic contractile activity. The dynamic courses of contraction and relaxation of peripheral microlymphovessels were continuously visualized by a CCTV system. The frequency spectrum analysis of microlymphomotion (FC, AMP, and ANG), the spreading speed of peristaltic wave (C mm/s) and the contractile index (CI) were measured by using the newly developed microlymphomotion image processing system. The results demonstrated that there were no significant differences between the frequency and amplitude of microlymphomotion existed above and below the valves of microlymphovessel. There were also no significant changes in the spreading speed of peristaltic wave at the up and down stream measuring points crossing lymphatic valve. But the contractile index crossing the valve increased significantly (P < 0.05). The down stream phase angle of microlymphomotion significantly led in comparison with that of upstream (P < 0.01). 654-2 could activate and enhance lymphomotion which was inhibited by NE. An energy conversion hypothesis of lymph flow and a pacemaker hypothesis of microlymphomotion were proposed.

Animals↗
PubMed1991

[Microcirculatory disturbances in patients with advanced AIDS].

CCTV-microscopic observation of nail-fold microcirculation was made on 11 AIDS patients and 11 healthy European adults. Unique severe microcirculatory disturbances were observed in these patients: (1) severe dysfunction of automatic alternative capillary blood flow perfusion. All the capillary loops in the same microscopic field emptied at the same moment and remained empty for a long time (3-100 seconds). Subsequent filling up of the capillary loops was very slow (1-2.5 min/loop). (2) remarkable damage of endothelial cells in the capillary wall. Some parts of the capillary wall were penetrated by some heterogeneous, visible and sludgy mass, making the wall swelled and the lumen narrowed. The wall tension in all the capillaries was markedly decreased. After the capillary loops had emptied, these damaged parts of the wall still remained in the field. These findings demonstrated the deep involvement of microcirculation in the pathogenesis of AIDS, and also showed the close relationship between microcirculation and the immune condition of the organism.

Acquired Immunodeficiency Syndrome↗