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Biomedical subjects

B Yin

Publications and source records attributed to B Yin.

At least 37 records · Page 2Linked to original sources
PubMed1999

[Cloning of full-length Dnmt3b cDNA and its alternative splicing isoforms in mouse embryo].

OBJECTIVE: To clone the novel full-length cDNA related to mouse embryonic development. METHODS: Starting from a new expression sequence (clone 2 #) out of a mouse embryonic cDNA library, its full-length cDNA were obtained by rapid amplification of cDNA ends with polyA RNA isolated from mouse 8-9 day embryonic tissue as template, combined with screening of mouse embryonic cDNA library by PCR. Based on the sequences at the two ends of the cDNA, the primers for long range RT-PCR were designed to confirm its factuality. RESULTS: The cDNA isolated in our hands was one of the alternative splicing isoforms of mouse de novo DNA cytosine 5'-specific methyltransferase gene (Dnmt3b) reported in July, 1998. A new alternative splicing region upstream of its initiate codon was found 5' forwards 152 bp over the Dnmt3b cDNA sequence. Eight alternative splicing isoforms of Dnmt3b from mouse embryonic tissue were cloned (Genbank accession number are AF151969, AF151970, AF151971, AF151972, AF151973, AF151974, AF151975, AF151976 respectively). CONCLUSIONS: The 4 kb full-length Dnmt3b cDNA was isolated. Dnmt3b may have novel exons at its 5' upstream and present a complex alternative splicing pattern during mouse embryonic development.

Alternative Splicing↗
PubMed1998

Lipoprotein lipase expression exclusively in liver. A mouse model for metabolism in the neonatal period and during cachexia.

Lipoprotein lipase (LPL), the rate-limiting enzyme in triglyceride hydrolysis, is normally not expressed in the liver of adult humans and animals. However, liver LPL is found in the perinatal period, and in adults it can be induced by cytokines. To study the metabolic consequences of liver LPL expression, transgenic mice producing human LPL specifically in the liver were generated and crossed onto the LPL knockout (LPL0) background. LPL expression exclusively in liver rescued LPL0 mice from neonatal death. The mice developed a severe cachexia during high fat suckling, but caught up in weight after switching to a chow diet. At 18 h of age, compared with LPL0 mice, liver-only LPL-expressing mice had equally elevated triglycerides (10,700 vs. 14,800 mg/dl, P = NS), increased plasma ketones (4.3 vs. 1.7 mg/dl, P < 0.05) and glucose (28 vs. 15 mg/dl, P < 0.05), and excessive amounts of intracellular liver lipid droplets. Adult mice expressing LPL exclusively in liver had slower VLDL turnover than wild-type mice, but greater VLDL mass clearance, increased VLDL triglyceride production, and three- to fourfold more plasma ketones. In summary, it appears that liver LPL shunts circulating triglycerides to the liver, which results in a futile cycle of enhanced VLDL production and increased ketone production, and subsequently spares glucose. This may be important to sustain brain and muscle function at times of metabolic stress with limited glucose availability.

Age Factors↗
PubMed1998

[Open heart surgery without cross clamping aorta].

Open heart surgery without cross clamping aorta under normothermic or hypothermic cardiopulmonary bypass was performed in 167 patients in which there were more than ten kinds of cardiac diseases. The characteristics of the procedure included only vena cava blocked and aorta unclamped with beating heart or artificial evoked ventricular fibrillation. It diminished myocardial ischemia and reperfusion injuries maximally. There were no low cardiac output syndrome, severe arrhythmia and complications of brain except two patients died postoperatively. The operative mortality rate was 1.1% (2/167). The advantages, disadvantages and safety of this method are discussed briefly in this paper.

Adolescent↗
PubMed1998

[Influence of MP infection on immunologic function in patients with chronic obstructive pulmonary disease].

The aim of this study was to detect Mycoplasma pneumoniae(MP) in sputum with chronic obstructive pulmonary disease(COPD) by using polymerase chain reaction and measured the level of sIL-2R in chronic pulmonary heart disease(CPHD) patients by Enzyme Linked Immnosorbert Assay(ELISA). At the same time, we also measured the level of the serum total IgE in CPHD patients. We determine the relationship between the sIL-2R and lymphocytes. The results showed that rate of MP infection in COPD patients was 34.59%. The rate of MP infection in CPHD patients and asthmatic patients were significantly higher than that in patients with chronic bronchitis. The level of sIL-2R in patients with CPHD who had MP infection increased significantly higher than that in CPHD patients which didn't have MP infection. There was a linear negative correlation between the level of sIL-2R and lymphocytes. The level of serum total IgE in CPHD patients with MP infection was higher than that in patients with other infection. These data suggest that MP is a common agent in COPD patients, particularly in CPHD and asthma. MP infection can impair the cellular immunity and immunotherapy combined with antibiotics may be more effective.

Adult↗
PubMed1998

[Total cavo-pulmonary connection for complex congenital heart disease].

Between April 1994 and January 1997, 10 patients with complex congenital heart disease were treated with total cavo-pulmonary connection(TCPC). They included 7 males and 3 females, aged 2-17 years(mean 10.1 years). These cases were single ventricle in 5, tricuspid atresia in 4, severe Ebstein anomaly in 1. For construction of the right atrial lateral tunnel, Gore-Tex patch was used in 9 cases and autologous right atrial wall in another, 4 of the 10 patients underwent TCPC without aortic crossclamping. There were no operative deaths. The follow-up is 2-36 months(mean 12.3 months). All of these patients did well and were in NYHA class I. The advantages, operative indication and technique of TCPC and the experience of improvement of surgical results are briefly discussed in this paper.

Adolescent↗
PubMed1998

[Clinical study of inhaled corticosteroid in non-asthmatic chronic obstructive pulmonary disease].

OBJECTIVE: There is less unanimity about the effects of inhaled corticosteroid in patients with non-asthmatic chronic obstructive pulmonary disease(COPD). The aim of this study is to determine whether patients with non-asthmatic COPD have favorable responses to inhaled corticosteroid (ICS). METHOD: A randomized, placebo-controlled, single-blind trial of inhaled beclomethasone dipropionate(BDP 1000 micrograms daily for 6 weeks) was carried out in 61 patients with stable non-asthmatic COPD. Before and after the therapy, the scores of clinical symptoms and the scores of quality of life were recorded, and the pulmonary function and plasma level of endothelin-1 (ET-1) were measured. RESULT: 58 patients finished the study. Compared with the placebo-group, after receiving 6 weeks of ICS therapy, the BDP group showed significant improvement in clinical symptoms (P < 0.05), but not in the quality of life (P > 0.05). There was also an improvement in FEV1(P < 0.001), but not in MMEF (P > 0.05). The plasma concentration of ET-1 was not changed significantly in both groups. CONCLUSION: The study suggested that the therapy of ICS (1000 micrograms daily for 6 weeks) can improve clinical symptoms and pulmonary function in patients with stable non-asthmatic COPD, but cannot affect the quality of life and the plasma concentration of ET-1.

Administration, Inhalation↗
PubMed1997

Lipoprotein lipase regulates Fc receptor-mediated phagocytosis by macrophages maintained in glucose-deficient medium.

During periods of intense activity such as phagocytosis, macrophages are thought to derive most of their energy from glucose metabolism under both aerobic and anaerobic conditions. To determine whether fatty acids released from lipoproteins by macrophage lipoprotein lipase (LPL) could substitute for glucose as a source of energy for phagocytosis, we cultured peritoneal macrophages from normal and LPL knockout (LPL-KO) mice that had been rescued from neonatal demise by expression of human LPL via the muscle creatine kinase promoter. Normal and LPL-KO macrophages were cultured in medium containing normal (5 mM) or low (1 mM) glucose, and were tested for their capacity to phagocytose IgG-opsonized sheep erythrocytes. LPL-KO macrophages maintained in 1 and 5 mM glucose phagocytosed 67 and 79% fewer IgG-opsonized erythrocytes, respectively, than macrophages from normal mice. Addition of VLDL to LPL-expressing macrophages maintained in 1 mM glucose enhanced the macrophages' phagocytosis of IgG-opsonized erythrocytes, but did not stimulate phagocytosis by LPL-KO macrophages. Inhibition of secreted LPL with a monoclonal anti-LPL antibody or with tetrahydrolipstatin blocked the ability of VLDL to enhance phagocytosis by LPL-expressing macrophages maintained in 1 mM glucose. Addition of oleic acid significantly enhanced phagocytosis by both LPL-expressing and LPL-KO macrophages maintained in 1 mM glucose. Moreover, oleic acid stimulated phagocytosis in cells cultured in non-glucose-containing medium, and increased the intracellular stores of creatine phosphate. Inhibition of oxidative phosphorylation, but not of glycolysis, blocked the capacity of oleic acid to stimulate phagocytosis. Receptor-mediated endocytosis of acetyl LDL by macrophages from LPL-expressing and LPL-KO mice was similar whether the cells were maintained in 5 or 1 mM glucose, and was not augmented by VLDL. We postulate that fatty acids derived from macrophage LPL-catalyzed hydrolysis of triglycerides and phospholipids provide energy for macrophages in areas that have limited amounts of ambient glucose, and during periods of intense metabolic activity.

Animals↗
PubMed1997

Endothelial cell heparanase modulation of lipoprotein lipase activity. Evidence that heparan sulfate oligosaccharide is an extracellular chaperone.

A unique feature of lipoprotein lipase (LpL), the rate-limiting enzyme in the hydrolysis of circulating triglycerides, is its movement from its cell of synthesis, adipocyte or myocyte, to its site of action, the luminal endothelial surface. This involves processes that allow LpL to be released from the adipocyte cell surface and transferred against the flow of interstitial fluid to the luminal surface of endothelial cells. LpL, an unstable enzyme, must retain its activity during this process. Whether a chaperone-like molecule is involved in LpL stabilization and transport is unclear. In the present study, we tested the hypothesis that endothelial cells secrete factors that release LpL and promote its transfer to the luminal endothelial surface. Incubation of adipocytes with endothelial cell conditioned medium (ECCM) led to release of about 2-fold more LpL activity than control medium. Medium from endothelial cells exposed to lysophosphatidylcholine (lyso-ECCM), a product of LpL lipolysis of lipoproteins, released approximately 3-fold more LpL than ECCM. Concomitant with the release of LpL, adipocyte cell surface heparan sulfate (HS) proteoglycans were degraded suggesting that lyso-ECCM contained a heparanase-like activity. More heparanase was found in media from the basolateral than the apical side of lysolecithin-stimulated polarized endothelial cells. In coculture experiments, lipolysis and lysolecithin stimulation of endothelial cells increased LpL release from adipocytes. LpL released by lyso-ECCM remained stable and did not lose enzymatic activity at 37 degrees C for 1 h. LpL activity was also stabilized by heparanase-digested fragments of HS (HS oligosaccharide) and by purified LpL binding decasaccharide. Moreover, LpL.HS oligosaccharide complexes crossed endothelial cell monolayers and bound to the apical side of the cells. Thus, an endothelial heparanase may play a critical role in releasing subendothelial HS bound proteins, and specific HS oligosaccharides produced by this enzyme may serve as extracellular chaperones.

Adipocytes↗
PubMed1997

[Clinical significance of HCG in both maternal serum and placental tissue in normal term women and patients with pregnancy induced hypertension].

OBJECTIVE: To determine the maternal serum level of HCG beta and the hormones in normal term women and patients with pregnancy induced hypertension. METHOD: Semiquantitative immunohistochemistry of placental tissue was used in 193 normal term women and patients with pregnancy-induced hypertension (PIH). RESULTS: A strongly positive correlation between the maternal serum level of HCG and the immunostained positive syncytiotrophoblasts (ST) was found (correlated coefficient: 0.65, P < 0.01). Maternal serum HCG was produced mainly from placental ST. Serum HCG beta and HCG positive cells of the placenta were obviously higher in patients with PIH than those in normal term women (P < 0.01). An increase of HCG level was noted in maternal serum and the placental tissue with PIH. CONCLUSION: Abnormal higher HCG level may affect the pathogenesis of PIH.

Adult↗
PubMed1996

Determination of lincomycin residues in salmon tissues by gas chromatography with nitrogen-phosphorus detection.

A sensitive method for the determination of lincomycin residues in fish tissues is described. Lincomycin was extracted from fish tissues with phosphate buffer (pH 4.5). The extract was concentrated with a C18 solid-phase extraction cartridge and further cleaned up by solvent extraction. Lincomycin was derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide to form a trimethylsilyl derivative before being analyzed by gas chromatography with nitrogen-phosphorus detection. Coumaphos was used as the internal standard. Assays showed good linearity in the range 25-250 ppb (ng/g) (r = 0.9994). Recoveries of fortified lincomycin at 50, 100 and 200 ppb were > 80% with relative standard deviations < 6%. The limit of detection of the method was 1.7 ppb and the limit of quantitation was 3.8 ppb.

Acetamides↗
PubMed1996

Coordinated movements between autosomal half-bivalents in crane-fly spermatocytes: evidence that 'stop' signals are sent between partner half-bivalents.

During anaphase-I in crane-fly spermatocytes, sister half-bivalents separate and move to opposite poles. When we irradiate a kinetochore spindle fibre with an ultraviolet microbeam, the associated half-bivalent temporarily stops moving and so does the partner half-bivalent with which it was paired during metaphase. To test whether a 'signal' is transmitted between partner half-bivalents we irradiated the spindle twice, once in the interzone (the region between separating partner half-bivalents) and once in a kinetochore fibre. For both irradiations we used light of wavelength 290 microns and a dose that, after irradiating a spindle fibre only, altered movement in 63% of irradiations (12/19); in 11 of the 12 cells both partner half-bivalents stopped moving after the irradiation. In control experiments we irradiated the interzone only: these irradiations generally did not stop chromosomal poleward motion but sometimes (14/29) caused poleward movement to each pole to be abruptly reduced to about half the velocity prior to irradiation. In double irradiation experiments we varied the order of the irradiations. In some double irradiation experiments we irradiated the interzonal region first and the spindle fibre second; in 75% (9/12) of the cells the half-bivalent associated with the irradiated fibre stopped moving while the partner half-bivalent moved normally, i.e. in 9/12 cells the interzonal irradiations uncoupled the movements of the partner half-bivalents. In other double irradiation experiments we irradiated the spindle fibre first and the interzone second: in 80% (4/5) of the cells the half-bivalents not associated with the irradiated spindle fibre resumed movement immediately after the irradiation while the other half-bivalent remained stopped. Interzonal irradiations therefore uncouple the poleward movements of sister half-bivalents and the uncoupling does not depend on the order of the irradiation. Our experiments suggest therefore that the irradiation of a spindle fibre causes negative ('stop') signals to be transmitted across the interzone and that irradiation of the interzone blocks the transmission of the stop signal.

Anaphase↗
PubMed1995

Determination of 8-hydroxydeoxyguanosine by an immunoaffinity chromatography-monoclonal antibody-based ELISA.

The postulated importance of oxidative damage to DNA in aging and age-related degenerative pathologies such as cancer has prompted efforts to develop sensitive quantitation methods. 8-Hydroxy-2'-deoxyguanosine (8-OHdG) is a widely used marker for oxidative damage to DNA. To develop an immunoassay for quantitation of 8-OHdG, two monoclonal antibodies have been developed and characterized by competitive enzyme-linked immunosorbent assay (ELISA). Antibody 1F7 has 50% inhibition at 5 pmol 8-OHdG and 1 x 10(5) pmol dG, while antibody 1F11 has 50% inhibition at 2.5 pmol 8-OHdG and 2000 pmol dG. Both antisera crossreact with guanosine and several structurally related derivatives, including 6- and 8-mercaptoguanosine, 8-bromoguanosine, 8-methylguanine, and 7-methylguanosine. Immunoaffinity columns were prepared with antibody 1F7, which exhibits higher selectivity than 1F11, to isolate 8-OHdG from DNA hydrolyzates followed by ELISA quantitation with antibody 1F11. This method allows the analysis of approximately one 8-OHdG/10(5) dG using 100 micrograms DNA. To validate the assay, DNA extracted from human placental tissues were assayed by both ELISA and HPLC with electrochemical detection. Values by both methods correlated well (r = 0.87, p < 0.001), but the levels determined by ELISA were approximately sixfold higher than those determined by HPLC. This may be due to oligonucleotides detected by the ELISA but not the HPLC method or crossreactivity with other damaged bases present in the immunoaffinity purified material. Placental samples from current smokers had significantly higher 8-OHdG by ELISA than those from nonsmokers (p < 0.05). The method of immunoaffinity purification combined with ELISA quantitation has sufficient sensitivity for detecting 8-OHdG in human DNA samples. Although absolute values are higher than those determined by HPLC, the method provides a good alternative to the HPLC-EC method for monitoring relative oxidative damage in molecular epidemiological studies.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1995

[Lipid peroxidation in plasma and the activity of superoxide dismutase (SOD) in pregnant women with premature rupture of membrane].

To investigate the condition of lipid peroxidation and antioxidation in premature rupture of membrane (PROM), we selected 50 women with PROM, without significant inducing factors, as study group, and 116 healthy and uneventful gestational age pregnant women as controls. Blood samples were collected from the maternal and umbilical cord vein. The concentration of plasma malondialdehyde (MDA) and the activity of erythrocyte superoxide dismutase (SOD), selenium glutathione peroxidase (SeGSH-Px) were determined. The results showed that the plasma concentrations of MDA in the maternal and umbilical cord vein were significantly higher in the PROM group than in the control group (P < 0.01), and the activity of erythrocyte SOD and SeGSH-Px were significantly lower in the PROM group than in the control group (P < 0.01). The levels in plasma of MDA and SeGSH-Px in erythrocyte were significantly higher in the maternal blood than in the umbilical cord blood, but the SOD activity was significantly lower. A positive correlation of MDA concentration in plasma was found both in the maternal and umbilical cord veins (P < 0.01). It is suggested that lipid peroxidation improved may be one of the factors of PROM induced, and one of the factors of other related diseases induced by PROM.

Female↗