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Biomedical subjects

X L Chen

Publications and source records attributed to X L Chen.

87 records · Page 5Linked to original sources
PubMed1989

[Ethanol for hepatic arterial embolization (experimental study)].

In this experiment, 27 dogs underwent hepatic arterial embolization (HAE) with 99% ethanol in 10 (group A), 75% ethanol in 10 (group B) and 60% ethanol in 7 (group C). By the laparotomy, catheter was inserted into hepatic artery and ethanol at dose of 0.3 ml/kg was injected within 20 seconds. Arterial angiography was taken before and after HAE. The dogs were sacrificed in 1, 2, 4, 8 weeks. Liver specimens were examined grossly and microscopically. Both A and B group showed satisfactory results of embolization, but 99% ethanol caused severe damage to hepatocytes, perisinusoidal area and bile ducts. Eight of 10 dogs died of hepatic failure and infection within two weeks. 75% ethanol mainly occluded the smaller arterial branches. Hepatocellular and biliary tract lesions were slight and reversible. All the animals survived normally except two. Group C had some mild and limited liver damage and scattering thrombosis which might result from intima lesion. This article also discusses the clinical availability of ethanol HAE.

Animals↗
PubMed1988

Cardiovascular effects and modulation of noradrenergic neurotransmission following central and peripheral administration of neuropeptide Y.

Experiments have been conducted to evaluate the effect of neuropeptide Y (NPY) administered at three distinct levels of the nervous system: 1) the posterior hypothalamic nucleus, 2) the spinal cord, and 3) the vascular noradrenergic neuroeffector junction. It was observed that NPY produced varying cardiovascular effects at these three distinct sites of the nervous system. Microinjections into the posterior hypothalamic nucleus resulted in an increase in blood pressure, which was reduced by prior microinjection of a muscarinic or H1-histamine antagonist but not an H2-histamine antagonist. In addition to the involvement of histaminergic and cholinergic pathways, the pressor effect of NPY appears to result from an increase in sympathetic outflow. NPY was also seen to decrease the potassium-induced release of norepinephrine (NE) from slices obtained from the posterior hypothalamic nucleus. In contrast to what was observed in the hypothalamus, the intrathecal injection of NPY at a level of T4 or T10 in anesthetized or T10 in unanesthetized rats resulted in a depressor effect as well as a decrease in heart rate. Both an alpha 2- and beta-adrenoceptor antagonist reduced the NPY effect. The depressor effect of intrathecal NPY was attenuated in rats pretreated with reserpine as well as in Spontaneously Hypertensive rats (SHR). These data suggest that the effects of NPY are closely associated with sympathetic preganglionic neurons in the spinal cord. At the vascular noradrenergic neuroeffector junction, NPY decreased the nerve stimulation-induced release of NE while potentiating the contractile response. Moreover, NPY potentiated the increase in perfusion pressure of the perfused mesenteric arterial bed in response to angiotensin, vasopressin, or phenylephrine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Functional characteristics of intramyocardial capacitance vessels during diastole in the dog.

In order to evaluate the functional characteristics of the intramyocardial capacitance vessels during prolonged diastole, we analyzed the response of coronary vein flow after stepwise changes of coronary artery pressure in anesthetized open-chest dogs by using our newly developed laser Doppler velocimeter with an optical fiber. The peripheral portion of the great cardiac vein was isolated and the optical fiber tip was inserted into the vessel. The left anterior descending coronary artery was cannulated and connected to a reservoir to regulate coronary perfusion pressure. Intracoronary adenosine administration was carried out to avoid any change in coronary vasomotor tone. After 15 seconds of occlusion of the perfusion route, the heart was arrested by pacing-off. Two seconds later, coronary perfusion pressure was increased stepwise to a preset target pressure. This procedure was repeated by changing target pressure at 4 (or 5) different pressure levels (31-105 mm Hg). The great cardiac vein flow became zero due to the cardiac arrest and remained at zero for a moment (dead time) after the initiation of reperfusion. Then the flow reappeared and increased with first order time delay. The presence of dead time indicates the existence of unstressed volume, and the first order time delay represents the product of resistance and capacitance. The unstressed volume with a minimal vasomotor tone for perfusion pressure of 60-90 mm Hg was 5.2 +/- 2.2 ml per 100 g left ventricle, which is comparable to coronary blood flow for several beats. The capacitance at perfusion pressure of 60-90 mm Hg was 0.08 +/- 0.04 ml/mm Hg per 100 g left ventricle, while that at low perfusion pressure (30-50 mm Hg) was 0.14 +/- 0.09 ml/mm Hg per 100 g left ventricle. These results indicate that the intramyocardial capacitance vessels have two functional components, and that the phasic nature of coronary vein flow is solely the result of the myocardial squeezing of the blood in the capacitance vessels.

Animals↗
PubMed1986

[Pleomorphic carcinoma of the pancreas--report of 3 cases].

The incidence of pleomorphic carcinoma of the pancreas is low. In 34 cases of non-endocrinic cancer of the pancreas detected pathologically by operation and autopsy in our hospital from 1961 to 1984, 3 were pleomorphic carcinoma, comprising 8.8%. In histology, the tumor was clearly characterized by the bizarre uninuclear and multinuclear giant cells with abundant eosinophilic cytoplasm and malignant spindle cells. In these 3 cases, the tumor was originated from the acinic epithelium in 2 and from the ductal epithelium in 1. This tumor should be differentiated from pleomorphic rhabdomyosarcoma, liposarcoma, fibrosarcoma and lymphosarcoma, etc.

Adult↗
PubMedDate not supplied

VEGF, bFGF and their receptors at the fetal-maternal interface of the rhesus monkey.

Placental development involves trophoblast outgrowth and a coordinated angiogenesis in the implantation site. In this study, expression of angiogenic factors, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), VEGF receptors, kinase insert domain-containing region (KDR), and bFGF receptor Flg was characterized at the maternal-embryonic boundary of the rhesus monkey on Day 17, 19, 28 and 34 of pregnancy. Immunohistochemistry and in situ hybridization showed that VEGF mRNA and protein were both strongly expressed in the cytotrophoblast, the blood vessels and certain immunocytes. These sites were also immunopositive for KDR. In addition to the vascular endothelial cells and the vascular smooth muscle cells, the protein and mRNA for bFGF were also detected in cyto/syncytiotrophoblast bilayer, whereas the staining for Flg protein was mainly localized in the cytotrophoblast cells. The staining degree of VEGF and bFGF in the villi gradually decreased with the development of placenta. Strong expression of bFGF, Flg and KDR was also detected in the decidual cells. These data suggest that VEGF and bFGF may be involved in angiogenesis, cytotrophoblast proliferation and migration during early stage of placentation in the rhesus monkey.

Animals↗
PubMedDate not supplied

Cyclic ADP-ribose as a second messenger revisited from a new aspect of signal transduction from receptors to ADP-ribosyl cyclase.

Cyclic ADP-ribose (cADPR), an endogenous modulator of ryanodine receptor Ca(2+)-releasing channels, is found in various tissues. Cytosolic injection of cADPR induces an elevation of intracellular Ca(2+) concentrations or potentiates Ca(2+) increases. cADPR facilitates neurotransmitter or insulin release and modifies ionic currents. cADPR is synthesized by ADP-ribosyl cyclase and is metabolized by cADPR hydrolase. ADP-ribosyl cyclase activity is up-regulated by nitric oxide/cyclic GMP-dependent phosphorylation or receptor stimulation via G-proteins within membranes. These findings suggest that cADPR is a second messenger in cellular Ca(2+) signaling. However, many intriguing issues remain to be addressed before this identity is confirmed.

ADP-ribosyl Cyclase↗
PubMedDate not supplied

Effects of cancer chemotherapy on the blood fibrinogen concentrations of cancer patients.

Blood fibrinogen concentrations and glutamic-pyruvic transaminase activities of 66 adult cancer inpatients (aged 22 - 70 years) were determined both before and after one or two chemotherapy regimens. The percentage of hepatoma patients with abnormal blood fibrinogen levels (< 1.5 or > 6.0 g/l) was higher (64.3% of 14 patients) than that in other cancer categories (19.2% of 52 patients). The mean blood fibrinogen concentrations of male (3.5 g/l) and female (4.5 g/l) cancer patients were higher than those previously reported for healthy humans (2.8 and 2.9 g/l, respectively). After chemotherapy, blood fibrinogen concentrations decreased in patients whose primary tumours were surgically removed (from 4.8 to 3.2 g/l) but increased (from 3.0 to 4.8 g/l) in those who did not undergo surgery. Glutamic-pyruvic transaminase activities did not appear to be related to blood fibrinogen levels. We conclude that the increase in mean blood fibrinogen levels of cancer patients is probably related to tumour growth. Different mechanisms may operate in patients with hepatoma.

Adolescent↗