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Biomedical subjects

D Chen

Publications and source records attributed to D Chen.

At least 541 records · Page 30Linked to original sources
PubMed1997

[Observation on oligodendroglioma with light, electron microscopy and immunohistochemistry].

OBJECTIVE: To investigate the ultrastructural and histological characteristics of oligodendroglioma (ODG). METHODS: By means of light microscopy and partially electron microscopy and immunohistochemistry, 65 cases of ODG were observed. RESULTS: According to WHO classification of the tumor, all 65 cases of ODG were graded in the degree of differentiation of tumor cells, showing 19 cases of Grade I, 32 cases of Grade II and 14 cases of Grade III. CONCLUSIONS: (1) The presence of glial filaments in tumor cells may be explained as a heterogeneity in differentiation. (2) Besides the degree of differentiation, some other criteria such as cellular density and mitotic activity are also closely related to the grading of ODG.

Adolescent↗
PubMed1997

[Cardiovascular effects of diabetic autonomic neuropathy in NIDDM with coronary heart disease].

42 coronary heart disease (CHD) (21 with NIDDM) were studied with a noninvasive cardiovascular autonomic function tests Namely; 1. Heart rate response to valsalva manoeuvre; 2. Immediate HR response to standing; 3. BP response to standing; 4. BP response to sustained handgrip, on two groups; Group 1: 21 NIDDM with CHD; Group 2: 21 CHD. The results showed that the incidences of abnormal of 4 tests were: 28.6%, 42.9%, 19.0%, and 42.9% in Group 1 respectively, and all were 0% in Group 2. Significant difference (P < 0.05) was found between two groups. It suggested that cardiovascular autonomic function tests is useful in diagnosing autonomic neuropathy in NIDDM with CHD patients.

Aged↗
PubMed1997

[The inhibitory effects of antioxidant vitamins on serum oxLDL and experimental atherosclerosis of rabbits].

OBJECTIVE AND METHODS: In order to study the inhibitory effects of antioxidant vitamins on serum (low oxidative density lipoproteins, oxLDL) and experimental atherosclerosis in rabbits, 20 rabbits were fed on cholesterol rich diet and antioxidant vitamins (vitamin E, vitamin C and beta carotene) for 12 weeks. oxLDL were tested by ELISA at the beginning of experiment and after 4 weeks 8 weeks. RESULTS: The results showed that supplement of antioxidant vitamins can decrease the oxLDL level significantly and inhibited development of atherosclerosis lesion around aorta in rabbits.

Animals↗
PubMed1997

[Prospective study of central venous catheter-related sepsis in critically ill patients].

To evaluate the incidence of central venous catheter-related sepsis (CRS) in critically ill patients, we performed a prospective study of the central venous catheters (CVCs) in ICU of the Peking Union Medical College Hospital from Jan. 1995 to March 1996. Of 151 CVCs, 13 (8.6%) had CRS, with an incidence of 16.7 episodes per 1000 catheter-days. Presence of infectious focus at catheterization, catheter insertion site, duration of catheterization, and the decrease of body temperature after catheter removal correlated with definite CRS, while difficulty of insertion, body temperature at catheter removal, as well as the decrease of body temperature after catheter removal correlated well with no CRS. The study showed that CRS is a serious problem in critically ill patients. Careful manipulation of CVCs is a major determinant in reducing the incidence of CRS.

Catheterization, Central Venous↗
PubMed1997

[Hepatic resection and hepatic arterial chemoembolization for primary liver carcinoma].

Three hundreds of primary liver carcinoma (PLC) were subjected to hepatic resection and hepatic chemoembolization (HACE). Among them, hepatic resetion was performed in 106 cases, and HACE in 194. The two-stage operation after HACE was performed in 23 cases. Hepatitis B antigen was positive in 69.8%. PLC with cirrhosis accounted for 81.6%. The effect of hepatic resection was superior to HACE. The cause of early local recurrence after HACE can be a valuable therapy in the hepervascular PLC. However, HACE should be unsuitable for ischemic PLC. Quantitative estimation of hepatic resection of PLC with cirrhosis was dependent on 5 parameters (ALT, serum bilirubin, PT and R15TCG), and morphological changes of cirrhotic liver.

Adult↗
PubMed1997

The long-term effect of captopril treatment on endothelial function in spontaneously hypertensive rats.

The aim of this study is to elucidate the long term effect of captopril treatment on the endothelial function to release nitric oxide (NO) in spontaneously hypertensive rats (SHR). The properties of endothelium were determined with a model of hindquarter perfusion in response to alpha 1 adrenergic agonist, phenylephrine, at the age of 40 weeks of SHR which was administrated with captopril (100 mg/kg/day) from intrauterine and withdrawn at 16 weeks of age. Furthermore, in the presence of N omega-nitro-L-arginine methyl ester (LNAME), or L-arginine, the responses to phenylephrine were studied. From the curve of perfusion pressure, the minimal, maximal perfusion pressure (PPmin, PPmax) and the maximal slope (slope), as well as the 50% of effective concentration (EC50) were obtained. The data show that in captopril treated SHR, PPmin, PPmax and slope were markedly lower, but EC50 higher than those of untreated SHR. The curve induced by phenylephrine was significantly right shift compared with that of untreated SHR. Like WKY, the intensive reactivity to phenylephrine in the presence of LNAME was much lower than that of untreated SHR. In the presence of L-arginine, however, the right shift of curves was seen only in captopril treated SHR and WKY rats, but not in control SHR. In conclusion, endothelium does involve in the response of resistant vessel to phenylephrine. The mechanism of enhanced reactivity in untreated SHR may be, at least in part, due to the diminished capacity of producing NO from endothelium, and the effect of sustained hypotension of early captopril treatment might be relevant to the improved ability of endothelium.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

Neutrophil infiltration is involved in 5-fluorouracil induced lipid peroxidative damage of the small intestine.

UNLABELLED: This study evaluated the mechanisms of 5-fluorouracil (5-FU) induced intestinal damage by investigating the lipid peroxide (LPO) level, myeloperoxidase (MPO) activity and disaccharidase activity in rats. Group I animals (n = 6) were sacrificed and served as a normal control group. Group II animals (n = 24) were given a single intraperitoneal injection of 5-FU (150 mg/kg) and every 8 rats were sacrificed on day 1, 3 and 5 after injection respectively. RESULTS: LPO concentration in blood and intestinal mucosa was significantly higher in the group II than in the group I on day 1 and 3 (P < 0.05). MPO activity was significantly higher in the group II than in the group I at different times (P < 0.01). Lactase activity on day 5 (P < 0.01); sucrase activity (P < 0.01 and P < 0.05 respectively) and maltase activity (P < 0.01) on day 3 and 5, were significantly lower in the group II than in the group I. CONCLUSION: The results indicate that neutrophil infiltration may be involved in 5-FU-induced lipid peroxidative damage of the small intestine which was reflected by the decreased disaccharidases activities.

Animals↗
PubMed1997

[Histologic and SEM studies on aging changes of temporomandibular articular disc in young growing rats].

The normal aging changes of the temporomandibular articular discs in young growing SD rats were studied with histologic and scanning electron microscope methods. The results showed that the active remodeling growth was found in the discs of the rats from 3 to 9 weeks, which characterized as the changes from the young cellular connective tissues to fiberous cartilage gradually, these changes were consistent and adaptable with the growth of the condyle. The wave-like structures on the superior surface of discs of the rats from 5 to 8 weeks were varied morphologically in different bands and ages.

Age Factors↗
PubMed1997

[Histologic and histochemical studies on the temporomandibular articular disc in young growing rats after functional mandibular advancements].

The purpose of these studies was to detect the patterns of the changes in the site of temporomandibular articular disc in the young growing SD rats after the functional protrusive appliance inserted with histologic and histochemical methods. The results showed that collagen fibres were dense, roughly paralleled linked especially anterioposteriorly after the mandible protruded functionally, chondrocytes and gycosaminoglycans contents increased apparently in the posterior band of the discs. The adaptive remodeling of the discs might be the results of the pressure of the condyle on the discs and the lateral pterygoid muscle to it. The remodeling growth of the discs were coordinate and adaptive with the proliferative changes of the condylar cartilage after the mandible protruded functionally. No pathological changes were found in the rat articular discs.

Animals↗
PubMed1997

[Immunohistochemical study on the temporomandibular articular disc in young growing rats after functional mandibular advancements].

In the present experiment the type I collagen of discs was investigated with immunohistochemistry in the young growing SD rats after the mandible protruded functionally. The experimental evidence showed that the immunohistochemical staining reactions accentuated with age changed in control group discs, and the immunohistochemical staining reactions in experimental group were intenser than in control group. It indicated that the discs synthesized higher contents of type I collagen after the disc accepted more functional stimuli in the experimental group.

Age Factors↗
PubMed1997

[Identification of deer's foetus and its mixed drugs and flase drugs].

In this paper, the traditional Chinese Materia Medicas--the foetuses of sika deer, red deer and the one of sheep and OX are compared and identified on characters and dissecting characteristices. The comparion and identification table about charaeters and commodity shape drawings is attached.

Animals↗
PubMed1997

[Enhanced emission spectra of Yb, Eu, Y and Sm HCLS with high current microsecond pulsed supply].

The emission spectra of Yb, Eu, Y, Sm hollow cathode lamps have been investigated with a high current microsecond pulsed (HCMP) supply developed in our laboratory. Both atomic and ionic emission lines of interest of these rare earth elements are enhanced by tens to tens of thousand times in HCMP mode compared to DC mode. Effects of parameters of the supply on emission intensities are surveyed. HCMP HCLs may be used as an economic and convenient excitation source for atomic/ionic fluorescence spectrometric analysis.

English Abstract↗
PubMed1997

[Development of a SIRI-TOFMS and the application research progress].

The only one set of Sputter Initiated Resonance Ionization-Time of Flight Mass Spectrometer (SIRI-TOFMS) in China was designed and developed. A liquid gallium ion source with micron level diameter of beam, frame-style piezoeletric ceramic sub-micron sample manipulator, a secondary electron imaging system and a computer controlled precise targeting system as well as a real colour big screen image displaying system were added so as to improve its microanalysis capability. By means of this apparatus, trace analysis of Au in minerals and Cu in standard steel samples were carried out. The detection limit of them is 40ng/ and microg/g level, respectively. Aside from the above detections, other preliminary researches ere also performed.

English Abstract↗
PubMed1997

Vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) in normal and atherosclerotic human arteries.

Vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) is an endothelial-cell-specific mitogen; as such, its role in angiogenesis has been studied extensively. VEGF/VPF may also serve as a local, endogenous regulator of large-vessel endothelial cell integrity. Surprisingly, however, VEGF/VPF expression in normal and/or atherosclerotic vessels has not been previously characterized. Accordingly, we studied normal human arteries and veins as well as atherosclerotic and restenotic human coronary arteries for evidence of VEGF/VPF expression. VEGF/VPF was detected immunohistochemically in sections of normal human aorta, mammary artery, and saphenous vein. Moreover, VEGF/ VPF expression was identified in 32 (97%) of 33 pathological coronary arterial specimens; the extent of VEGF/VPF staining was graded as moderate to strong in 21 of the 32 (66%) positive specimens. VEGF/VPF double immunostaining and in situ hybridization demonstrated that smooth muscle cells constitute the principal cellular source of VEGF/VPF. VEGF/VPF immunostaining among primary atherosclerotic lesions localized predominantly to the extracellular matrix. In restenotic specimens, VEGF/VPF immunostaining was more prominently cellular, particularly among proliferating smooth muscle cells. Although VEGF/VPF expression was observed in areas of macrophage infiltration, double immunostaining failed to localize VEGF/VPF to macrophages in these foci; instead, double immunostaining clearly identified CD45RO-positive cells as responsible for VEGF/VPF expression in such areas. No correlation could be demonstrated between VEGF/VPF immunostaining and extent of vasa vasorum. These findings thus establish that postnatal VEGF/VPF expression is a feature of normal human arteries and veins and is often extensively expressed in arteries narrowed by atherosclerotic plaque. VEGF/VPF expression in the wall and/or plaque of medium to large vessels suggests a role for VEGF/VPF other than promoting angiogenesis. This role may involve maintenance and repair of luminal endothelium.

Aorta, Thoracic↗
PubMed1997

Construction of a Salmonella typhimurium vaccine strain expressing Vibrio cholera CT-B and LPS-O antigen.

The genes encoding V. cholera CT-B and LPS-O antigens were simultaneously inserted into the vector plasmid pYA248. The resulting recombinant plasmid pMG306 was transformed into the delta cya delta crp delta asd attenuated S. typhimurium vaccine strain x4072, and the live vaccine strain x4072 (pMG306) was constructed. This vaccine strain could secrete a specific CT-B antigen. Meanwhile, LPS-O antigens of both V. cholera and S. typhimurium were expressed on the cell surface. Mouse intraperitoneal immunization and subsequent challenge trial indicated that x4072 (pMG306) provided good protection against virulent V. cholera. This study has laid the foundation for the development of a new cholera-typhoid bivalent live oral vaccine.

Agglutination Tests↗