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Biomedical subjects

X Bian

Publications and source records attributed to X Bian.

At least 55 records · Page 3Linked to original sources
PubMed1998

[A endothelial coverage in the autogenous vein graft for arterial reconstruction in the early stage].

OBJECTIVE: To sequentially study the endothelial cell(EC) in the autogenous vein graft(AVG) for arterial construction in the early stage. METHODS: Forty dogs were divided in to two groups. After the artery reconstructed and intravenous injection or nonintravenous injection of PGE1, the dogs were divided in to groups. The deendothelialization and reendothelialization of AVG were determined by the portrayal apparatus. RESULTS: Excellent results in renovation of EC to the AVG were observed after establishment of running off of was reconstructed artery without intravenous injection of PGE1. The valve of AVG is very important in renovation of EC. CONCLUSION: It must be protected when artery is reconstructed by AVG.

Animals↗
PubMed1997

Roles of cytoplasmic Ca2+ and intracellular Ca2+ stores in induction and suppression of apoptosis in S49 cells.

The Ca2+-ATPase inhibitors, thapsigargin and cyclopiazonic acid, depleted intracellular Ca2+ stores, induced large increases in intracellular Ca2+ concentration, and caused apoptosis in S49 cells. Removal of extracellular Ca2+ augmented apoptosis due to thapsigargin, indicating that depletion of Ca2+ from intracellular stores is responsible for apoptosis with this agent. Overexpression of the apoptosis suppressor, Bcl-2, inhibited apoptosis due to thapsigargin but did not affect thapsigargin-induced Ca2+ signaling. Dexamethasone induced apoptosis, diminished the size of the endoplasmic reticulum Ca2+ pool, and caused a small elevation of intracellular Ca2+. However, this elevation was not due to Ca2+ influx because the increase was similar in the presence or absence of Ca2+ in the medium. Furthermore, in contrast to the results with thapsigargin, apoptosis due to dexamethasone was unchanged in a Ca2+-free medium. These results indicate that depletion of Ca2+ stores initiates a pathway leading to apoptosis. Elevations in cytoplasmic Ca2+ appears to play a lesser role than previously thought in the actions of Bcl-2 and glucocorticoids.

Apoptosis↗
PubMed1997

[Proliferative activities, oncoprotein expression and their significance in human gliomas].

OBJECTIVE: To explore the relationship between the proliferative activities, oncoprotein expression, cell differentiation and prognosis of gliomas. METHODS: Immunohistochemistry and image analysis were used to study the expression of proliferating cell nuclear antigen (PCNA) and several oncoproteins both qualitatively and quantitatively in 124 brain gliomas. RESULTS: It was found that the intensities of PCNA reaction were significantly related to both the grade and prognosis of gliomas. Overexpression of c-erbB-2 protein was slightly stronger in well than in poorly-differenciated gliomas. Moreover, the reactions in patients who survived over 5 years were stronger than in those under 5 years. EGF (40.0%), EGFR (91.4%) and p21ras (53.3%) expression levels were related to neigher the grading nor prognosis of this tumor. The positive ratios of the three antibodies to p53 protein were higher in grades II-IV than in grade I gliomas. The intensity of p53 reaction was correlated to that of PCNA. CONCLUSION: It is suggested that the aberration of c-erbB-2, p21ras, EGF and EGFR might be the early events in the initiation and progression of gliomas, whereas p53 is involved in all stages of these tumors. PCNA could reflect the degree of malignancy to a certain extent.

Brain Neoplasms↗
PubMed1997

[Effects of nordihydroguaiaretic acid on the growth and differentiation of SHG-44 glioma cell line].

OBJECTIVE: To investigate the effects of nordihydroguaiaretic acid (NDGA) on the growth and differentiation of glioma cells and their mechanism. METHODS: A human glioblastoma cell line (SHG-44) was treated with NDGA in the medium or intracytoplasmic microinjection of NDGA. Changes of the growth, morphology, cell cycle and immunohistochemical features of the cell were investigated. RESULTS: It was found that the growth rates and proliferation activity were inhibited by 100 mumol/L NDGA in the medium, with cell cycles altered. NDGA could induce differentiation of these cells with the glial filaments increased, and the treated cells expressed more GFAP but less vimentin. The expression of p53 and bFGF were also decreased. Furthermore, the result of microinjection (1.5 x 10(-11) g/cell) showed similar but more rapid and permanent effects on the glioma cells. CONCLUSION: NDGA has multiple effects of growth inhibition, differentiation therapy, as well as angiosuppression on human glioblastoma cells.

Brain Neoplasms↗
PubMed1997

[Study on polysaccharide of Lobaria kurokauae].

LOK polysaccharide is isolated from Lobaria kurokauae. By chromatography, LOK is shown to be sing substance. By gas chromatography analysis, LOK composes of rhamnose, arabinose, xylose, mannose, glucose and galactose. Their molecule ratio is about 1.00:1.34:1.12:10.13:6.99:6.47. Its mean molecule weight is estimated to be 1.5 x 10(4), its main chain is joined by a (1-->4) and a (1-->6) glucosidic linkages.

Chromatography, Gas↗
PubMed1997

Combination of ultrasound pelvimetry and fetal sonography in predicting cephalopelvic disproportion.

OBJECTIVE: To assess a method of antepartum diagnosis of cephalopelvic disproportion by comparing the diameters of fetal head with those of the maternal midpelvis. METHODS: Transvaginal ultrasound pelvimetry was performed on 190 healthy primigravidas with cephalic presentation at 28-35 weeks of gestation, and the fetal heads were measured within one week before delivery. The cephalopelvic indices of diameter, circumference and area were calculated and compared. RESULTS: The index exhibiting the highest degree of accuracy (77.9%) was the cephalopelvic index of diameter (CID) defined as the difference between the mean diameter of the midpelvis and the fetal biparietal diameter (BPD). Eighty-three percent of the cases with CID less than 15.8 mm needed operative delivery, and 76.2% of the cases with CID more than 15.8 mm underwent vaginal delivery. CONCLUSIONS: The CID may be used to identify cephalopelvic disproportion before the labor and help obstetricians choose the most appropriate form of delivery in an uncomplicated vertex presentation.

Cephalometry↗
PubMed1996

cGMP is not required for capacitative Ca2+ entry in Jurkat T-lymphocytes.

In this study, we have addressed the potential role of cGMP in regulating calcium entry in Jurkat T-lymphocytes. These cells display capacitative Ca(2+)-entry in response to the intracellular Ca(2+)-ATPase inhibitor, thapsigargin (TG). In the presence of extracellular Ca2+, TG stimulates a sustained elevation of intracellular cGMP levels. In the absence of extracellular Ca2+, TG induces no apparent increase in the levels of cGMP. However, experiments using Mn2+, as a surrogate for Ca2+, demonstrated that TG increased the rate of divalent cation entry in the absence of extracellular Ca2+. Treatment of Jurkat cells with the guanylyl cyclase inhibitor, LY83583 (20 microM), completely blocked cGMP formation in response to TG. However, LY83583 treated cells still exhibited a sustained, albeit partially reduced, Ca2+ response induced by TG. These data demonstrate that, in Jurkat cells, the sustained formation of cGMP is dependent on elevated intracellular Ca2+, and that elevated levels of cGMP are not necessary for the activation of capacitative Ca2+ entry.

Aminoquinolines↗
PubMed1996

Cordocentesis: a useful method for prenatal diagnosis.

OBJECTIVE: To evaluate the efficacy and safety of cordocentesis for prenatal diagnosis of various fetal diseases. PATIENTS AND METHODS: Fetal blood sampling was performed in 30 pregnancies from gestational week 19 to 36 for various prenatal diagnoses. We used Aloka SSD-650 real-time ultrasound scanner with 3.5 mHz curvilinear transducer during the procedure. A regular 22-gauge spinal needle was used for fetal blood sampling. RESULTS: Twenty-five cordocentesis were successful at the first attempt. A second attempt of cordocentesis succeeded in three cases. In the remaining two cases, intrahepatic vein sampling and cardiocentesis were employed respectively. The duration of procedure was shorter than 15 minutes in 25 cases. 1-6 ml of fetal blood was obtained from each case. Fetal blood was diluted with amniotic fluid in four samples. Maternal blood contamination never happened. No lethal complication occurred in our series. CONCLUSION: It is believed that cordocentesis is a safe and useful method for prenatal diagnosis, and intrahepatic vein sampling is an alternative choice when cordocentesis has failed.

Cordocentesis↗
PubMed1996

[An ultrastructural study on human retina with late glaucoma].

OBJECTIVE: To study the pathologic changes of retina in glaucoma. METHOD: Retinas from 6 cases with absolute glaucoma were observed by transmission electron microscope. RESULT: It was found that the nerve fiber layer was significantly thin and the axons were severely damaged even lost; the ganglion cells nearly disappeared and a number of cell-like bodies were seen instead; the nerve cells of the outer and inner nuclear layers were degenerated, decreased in number, and disorderly arranged; the outer segments of the cone and rod cells became degenerative and edematous. CONCLUSION: In advanced glaucoma the degeneration and atrophy of the ganglion cells and their nerve axons were the major pathologic changes of the retina that lead to the permanent damage of visual function.

Female↗
PubMed1996

[Cordocentesis for prenatal diagnosis of fetal diseases].

For the purpose of prenatal diagnosis, 30 fetal blood samplings were performed in 30 pregnant women from 19 to 36 gestational weeks. The samples were taken with a 22-gauge needle guided by ultrasound. Twenty-five cordocenteses were succeeded at the first attempt. A second attempt was needed in other 5 cases. The duration of procedure was less than 15 minutes in 83.3% cases. 1-6 ml fetal blood was obtained for each case. No lethal complication occured in our series. It is believed that cordocentesis could be a useful tool for prenatal diagnosis, and the intrahepatic-vein sampling is a preferable alternative choice if cordocentesis fails.

Cordocentesis↗
PubMed1995

Role of cyclic GMP in the control of capacitative Ca2+ entry in rat pancreatic acinar cells.

We have investigated the possible roles of cyclic GMP (cGMP) in initiating or regulating capacitiative Ca2+ entry in rat pancreatic acinar cells. In medium containing 1.8 mM external Ca2+, thapsigargin activated Ca2+ entry and slightly but significantly increased intracellular cGMP concentration. This rise in cGMP levels was prevented by pretreating the cells with the guanylate cyclase inhibitor, LY-83583, or by omitting Ca2+ during stimulation by thapsigargin or methacholine. LY-83583 and NG-nitro-L-arginine (L-NA, an inhibitor of NO synthase) both had a small inhibitory effect on Ca2+ entry when they were added after thapsigargin in Ca2(+)-containing medium, and they reduced by 32 and 48% respectively the thapsigargin-induced capacitative Ca2+ entry when added to the cells during a 20 min preincubation period. However, neither dibutyryl cGMP (Bt2cGMP) nor sodium nitroprusside, an NO mimic, affected either basal intracellular Ca2+ concentration [Ca2+]i or thapsigargin-induced capacitative Ca2+ entry. Further, the inhibitory effects observed after preincubation with LY-83583 or L-NA could not be prevented by preincubation with Bt2cGMP, nor could they be reversed by adding Bt2cGMP, 8-bromo-cGMP or sodium nitroprusside acutely after activation of capacitative Ca2+ entry by thapsigargin. Finally, pretreatment of cells with LY-83583 or L-NA did not affect Ca2+ signalling in response to 1 microM methacholine, including the pattern of [Ca2+]i oscillations. In conclusion, in pancreatic acinar cells, the rise in cellular cGMP levels appears to depend on, rather than cause, the increase in [Ca2+]i with agonist stimulation.

Aminoquinolines↗
PubMed1995

The Ca(2+)-mobilizing actions of a Jurkat cell extract on mammalian cells and Xenopus laevis oocytes.

Randriamampita and Tsien (Randriamampita, C., and Tsien, R. Y. (1993) Nature 364, 809-814) suggested that an acid-extracted fraction from a Jurkat cell line contains a messenger responsible for the coupling of calcium entry to the depletion of intracellular stores, i.e. capacitative calcium entry. We found that the extract, prepared as described by Randriamampita and Tsien, caused Ca2+ entry in 1321N1 astrocytoma cells which was not blocked by the D-myo-1,4,5-trisphosphate-receptor antagonist, heparin. In contrast to astrocytoma cells, when applied to mouse lacrimal acinar cells and rat hepatocytes the Jurkat extract always caused the release of intracellular Ca2+, followed by Ca2+ entry across the plasma membrane. This activity of the extract on lacrimal cells was blocked by either intracellular injection of heparin or extracellular atropine. Similarly prepared lacrimal cell extracts gave Ca2+ responses when applied to astrocytoma cells or lacrimal cells which were similar to those for Jurkat-derived extract. However, extracts from hepatocytes had no effect. In most Xenopus oocytes, the Jurkat extract had no effect, while in a few oocytes, the extract gave a [Ca2+]i response similar to that seen in lacrimal cells, that is, release of Ca2+ followed by Ca2+ entry. We conclude that the actions of the Jurkat cell extract are not consistent with its containing the long sought messenger for capacitative calcium entry. It is likely that this fraction contains a number of factors that mediate Ca2+ response in different cell types, possibly through receptor-mediated mechanisms.

Animals↗