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Biomedical subjects

B Sun

Publications and source records attributed to B Sun.

At least 163 records · Page 9Linked to original sources
PubMed1998

[Effect of dietary calcium on serum calcium and calmodulin activity of brain and hypothalamus in rats].

The effect of low calcium (LC) diet supplemented with various amount of calcium on serum calcium and calmodulin of rats was studied. The LC diet was mainly composed of corn low in calcium. The calcium content of LC diet was only half of that of the stock diet. Seventy Wistar rats were divided into 7 groups by weight and sex. Results showed that serum calcium in LC group was low and calmodulin activity was also low. These parameters were improved while calcium was supplemented in LC diet. There is a significant dose-response relationship among diet calcium, serum calcium and growth. When the total calcium in diet was increased up to 1000 mg/kg, serum calcium level was closed to that of normal and higher than the serum calcium in LC group significantly. The study demonstrated that low dietary calcium, hypocalcemia and low calmodulin are associated. When total dietary calcium was up to 1000 mg/kg, the growth retardation was attenuated.

Animals↗
PubMed1998

[Inhibition of apoptosis by bcr-abl fusion gene in K562 cells].

OBJECTIVE: To investigate the effect of bcr-abl fusion gene on CML cell apoptosis. METHODS: Apoptosis of in vitro cultured K562 cells was observed after exposure to synthetic 18-mer antisense oligodeoxynucleotide complementary to the bcr-abl junction (b3a2). RESULTS: Apoptosis of K562 cells was significantly increased associated with inhibition of bcr-abl expression. CONCLUSION: bcr-abl fusion gene formation due to chromosome translocation may be the major mechanism of CML via inhibition of apoptosis.

Apoptosis↗
PubMed1998

[Effect of antisense oligodeoxynucleotide (ASODN) to PML-RAR alpha fusion gene on acute promyelocytic leukemia cell line NB4].

OBJECTIVE: To study the effect of PML-RAR alpha expression on the proliferation and differentiation of NB4 cells, and explore the role of PML-RAR alpha fusion gene in the pathogenesis of acute promyelocytic leukemia (APL). METHODS: ASODN-mediated inactivation of PML-RAR alpha mRNA was measured by RT-PCR. The proliferation and differentiation of NB4 cells were determined by proliferation curve, morphology, membrane CD antigen and NBT test. NB4 cell cycle was analyzed by FACS. RESULTS: The inactivation of PML-RAR alpha mRNA by ASODN decreased the percentage of S phase cells (from 56% to 37%), inhibited the NB4 cell proliferation and induced NB4 cells to differentiate to morphologically and functionally mature granulocytes. CONCLUSION: PML-RAR alpha gene, as a molecular marker of APL, is possibly responsible for genesis of APL.

Cell Transformation, Neoplastic↗
PubMed1998

[Morphological studies of myocardial fibrosis in different types of Keshan disease].

OBJECTIVE: To clarify the localization, distribution, content and type of collagen in the myocardium of patients with Keshan disease (KD). METHODS: Picrosirium red staining, polarization microscopy and image analysis were used to study autopsy specimens from 335 KD patients. RESULTS: A loose network of collagen and a higher ratio of type III collagen were found in the myocardial scar tissues of acute KD patients. In the myocardial scar tissues from chronic KD patients, the collagen fibers were dense, the ratio of type I collagen was higher, the ratio of type I to type III is increased in chronic KD and decreased in acute KD. The amount of collagen in non-necrotic regions was significantly higher than that of the controls. CONCLUSION: The degeneration and necrosis of myocytes in KD is associated with disorders of collagen metabolism and with structural modelling of collagen.

Cardiomyopathies↗
PubMed1998

[The distribution of substance P in the lungs of asthmatic guinea-pigs and the influence of dexamethasone on the distribution].

OBJECTIVE: To investigate the distribution of substance P(SP) in the lungs of asthmatic guinea pigs and the effects of dexamethasone on its distribution. METHODS: Guinea pigs were divided into 3 groups: asthma group, dexamethasone-treated group and control group. Rabbit serum against SP, immunohistochemical ABC method and glucose-DAB-nickel technique for staining and computer image analysis were used in this study. RESULTS: There was distribution of SP-IR positive fibres in airways in asthma group than the other two groups. The positive fibres, emerged like a string of beads, were present as large fibre bundles in the smooth muscle layer and basement membrane. Additionally, in the asthma group SP-IR positive fibres were detected on the walls of respiratory bronchioles and alveolar ducts in contrast to the other groups. There was no difference in distribution and morphological characteristic between the control group and the dexamethasone-treated group. CONCLUSION: Repeated antigen challenges, which cause the allergic inflammation of airways, may result in the growth of SP-containing nerve fibres in the airway and synthesis of SP in neurons. These may be involved in the persistence and exacerbation of airway inflammation in asthma. Dexamethasone can reverse the distribution of SP-IR positive fibres to the normal status in airway walls of asthma guinea pigs.

Animals↗
PubMed1998

[TNF-alpha production and antitumor effect of rhIL-2-activated bone marrow cells].

OBJECTIVE: To explore the mechanism of the cytotoxic effects of bone marrow cells activated with recombinant human interleukin-2(rhIL-2). METHODS: The cytotoxicity of rhIL-2-activated bone marrow (ABM) and the TNF-alpha level in the supernant of ABM culture were measured after activated for 24 and 48 hours. RESULTS: The cytotoxic activity against HL-60 cells and the level of TNF-alpha were significantly increased in ABM as compared with that in non-ABM(P < 0.01). Meanwhile, there was a significantly positive relationship between the TNF-alpha levels in supernant and cytotoxicities of ABM. CONCLUSION: TNF-alpha produced by rhIL-2 activated bone marrow cells involved in the antitumor effect of ABM.

Bone Marrow Cells↗
PubMed1998

[Clinical significance of cytokine and eosinophil cationic protein concentrations in sputum of asthmatic patients].

OBJECTIVE: To examine whether levels of inflammatory cytokines and eosinophil cationic protein (ECP) in the sputum reflect the severity of bronchial asthma. METHOD: We collected sputum expectorated spontaneously from 15 asthmatics with acute attacks of moderate to severe degree (MS group) and 10 subjects with acute attacks of mild asthma (M group). The interleukin (IL)-5(35 ng/L) tumor necrosis factor (TNF)-alpha(M 149 +/- 59 ng/L, MS 267 +/- 147 ng/L), soluble IL-2 receptor (sIL-2R) (M 348 +/- 107 kU/L, MS 488 +/- 127 kU/L) levels in the sputum were measured with enzyme-linked immunosorbent assay, and sputum ECP (M 127 +/- 95 micrograms/L, MS 278 +/- 150 micrograms/L) concentration were measured by Immuno-CAP System. RESULT: Sputum IL-5, TNF-alpha, sIL-2R, ECP concentrations in moderate to severe patients were significantly higher than in mild subjects. CONCLUSION: These findings suggest that inflammatory cytokines and mediator levels are detectable in the sputum from asthmatics and they might participate in the exacerbation of asthma.

Adult↗
PubMed1998

[Effects of 764-3 on collagen deposition in hypertensive pulmonary arteries in hypoxic rats].

OBJECTIVE: To investigate the changes of collagen deposition in pulmonary arteries in chronic hypobaric hypoxic rats and the roles of 764-3. METHODS: Wistar rats were divided into 10 groups. The hypoxic (50.7 kPa) rats were treated with 764-3 (20 mg/kg, once daily) and beta-aminopropionitrile (BAPN, 150 mg/kg, twice daily), respectively. At the end of treatment, the hemodynamic morphological and chemical parameters were measured. RESULTS: Comparing with the normals, hydroxyproline (HYP) content of extrapulmonary artery (EPA) increased obviously in hypoxic rats, the smooth muscle cells (SMC) in the media of muscular intra-acinar pulmonary artery showed hypertrophy with change in phenotype, and a striking increment of collagen accumulation (P < 0.001); 764-3 could reduce HYP content of EPA (P < 0.05-0.001), and most of SMC in the media became thin and elongated with reversion of change of SMC phenotype, and collagen accumulation was reduced (P < 0.001). In addition, BAPN was more effective than 764-3 (P < 0.05). CONCLUSIONS: Excessive collagen accumulation in pulmonary arteries plays an important role in the maintenance of hypoxic pulmonary hypertension. 764-3 can partially inhibit collagen deposition in pulmonary arteries, attenuate hypoxic pulmonary hypertension, and has a moderate influence on collagen deposition in compared with BAPN.

Aminopropionitrile↗
PubMed1998

[Relationship between endothelin-1 and ischemic brain damage after subarachnoid hemorrhage and protective effect of Ginkgo biloba extract].

OBJECTIVE: To investigate the role of endothelin-1 (ET-1) in development of ischemic brain damage after subarachnoid hemorrhage (SAH), and the protective effect of Ginkgo biloba extract (GBE). METHODS: Wistar rat noncraniotomy models of SAH were divided into SAH group and GBE treated group, the diameter of basilar artery (BA) and dynamic changes of regional cerebral blood flow (rCBF) and ET-1 content of intracranial plasma within 24 hours after SAH of both groups were determined. And pathological examination of CA1 region of hippocampus was performed 3 days later. RESULTS: rCBF decreased and ET-1 content increased obviously and retained in 24 hours after SAH. Spasm of BA occurred half an hour after SAH and neurons of hippocampus CA1 region was damaged severely. GBE could antagonize the above-mentioned pathological changes effectively. CONCLUSION: Increase of ET-1 is an important factor leading to ischemic brain damage after SAH. GBE exerts its protective effect by antagonizing pathological increase of ET-1.

Animals↗
PubMed1998

[Preliminary observation of immunotherapy on asthmatic guinea pig].

OBJECTIVE: To observe the effect of the anti-IL-5 monoclonal antibody(McAb) on eosinophils of the guinea pigs with asthma. METHOD: Sensitized guinea pigs by OVA were divided into two groups randomly, which were treated with the McAb and normal saline (NS), respectively. Difference of peripheral blood eosinophil count (PBEC) among basal pre-treatment and post-treatment, and the difference of bronchoalveolar lavage fluid eosinophil count (BALFEC) between two groups above were compared. RESULT: The PBEC after treatment with the McAb [(1.63 +/- 0.26) x 10(9)/L] was lower than that before treatment [(1.76 +/- 0.27) x 10(9)/L] (P < 0.05) and the BALFEC of treatment group with the McAb was lower than that with NS [(0.41 +/- 0.06) x 10(9)/L vs. (0.46 +/- 0.07) x 10(9)/L] (P < 0.05). CONCLUSION: The anti-IL-5 McAb has the ability to reduce the PBEC and the BALFEC.

Animals↗
PubMed1998

[A long-term evaluation for opticfull-thickness lamellar keratoplasty].

OBJECTIVE: To investigate the long-term optic effects of optic full thickness lamellar keratoplasty (OFLK) and penetrating keratoplasty (PKP) and compare their effects. METHODS: 44 cases (48 eyes) with stromal disorder with normal endothelial function were treated by OFLK (25 eyes) or PKP (23 eyes). The optic effect of OFLK group was compared with that of the PKP group, and the endothelial density in partial cases was observed. RESULTS: The rate of transparent graft of OFLK group was 84.0%, and that of PKP group was 69.6% at postoperative 2 - 3 years, the rate of escaping blindness being 80% and 78.3% respectively. The rate of obtaining more than 0.3 vision in OFLK group was 40.0%, and in PKP group was 21.7%. Postoperatively, the endothelial cell density tended to decrease with time in PKP group, but was relatively stable in OFLK group. CONCLUSION: The results show that the optic effect of OFLK group is similar to that of PKP group, and the safety, less complications of OFLK group are the same as that of lamellar keratoplasty. It is considered that OFLK might have a bright future and the operative technique should be further studied.

Adolescent↗
PubMed1998

[Peripheral corneal edema after cataract extraction].

OBJECTIVE: To report a rare type of corneal edema, i.e. peripheral corneal edema after cataract extraction---Brown-Mclean syndrome. METHODS: Clinical charts of 8 affected eyes in 5 patients were reviewed. Ultrasound pachymetry was used to determine central corneal thickness. Cell densities were measured by specular microscopy. The clinical characteristics and pathogenesis were discussed. RESULTS: The average time from operation to initial diagnosis was 10.5 years. The typical edema started inferiorly and progressed circumferentially, but central portion of the cornea was clear. The corneal thickness at edematous area was increased. The cell counts of endothelium was decreased in our patients. Additionally, the edema was associated with a punctate orange-brown pigmentation on the endothelium. CONCLUSIONS: So far this new syndrome of corneal edema has not been reported in china. Its clinical characteristics are not similar to that of conventional edema after intracapsular cataract extraction. The pathogenesis of this curious condition is still unknown. It may be associated with an aphakic eye, chronic uveitis and hereditary factors.

Adult↗
PubMed1998

[An experimental study on formation of cellular membrane on the surface of implanted posterior chamber intraocular lens].

OBJECTIVE: To observe the cellular reaction and membrane formation on the surface of intraocular lens (IOL) implanted in rabbit eyes and discuss the mechanism of early postoperative membrane formation and biological action. METHODS: 20 adult pigmented rabbit eyes were given posterior chamber IOL implantation. IOLs were extracted on the postoperative 1st, 3rd, 7th, 14th and 28th days respectively. Samples were observed under light microscope and scanning electron microscope (SEM). RESULTS: Macrophages on the surface of IOL had transformed into fibroblast-like cells and the formation of eosinophilic membrane had occurred on the 3rd day after operation with tiny thread-like things interwoven among cells forming net-like supporting membrane under SEM. CONCLUSION: It infers that the membrane is a kind of fibrinous film secreted by fibroblast-like cells and the cells involved in reaction are the biological foundation of membrane formation; this membrane will prohibit the serious cellular reaction at the end and keep IOL transparent.

Animals↗
PubMed1998

[Determination enzyme protein of CK-MB m-AST and ChE by immunological methods and survey of its applying values].

In recent decades, because considerable progress has been made due to rapid developments in basic theory and techniques in molecular biology and immunology, the determination of trace enzyme proteins is not difficult. We measured the serum concentration of Creatine kinase-MB (CK-MB) mitochondria aspartate aminotransferase (m-AST) and cholinesterase (ChE) immunologically and compared these findings with those of an assay of enzyme activity. Purification of enzyme protein and preparation of serum antibodies monoclonal antibodies established the immunological assay methods. Equipment and reagents for enzyme activity test use 7150 Biochemical Analyzer. CK-NAC AST and ChE were produced by trace kits (Australia). CK-MB and m-AST use immunological inhibition method. CK-MB m-AST ChE of protein determination used immunological turbidimetry. The normal group included 150 cases and the 1990 patient group. Results of the two methods did not significantly differ for normal controls, but were significantly different in the patient group. These results demonstrated that the two methods differ, although each may have specific clinical significance. How to evaluate these differences needs to be studied further, but immunological assay uses higher values for clinical diagnosis than enzyme activity assay.

Antibodies, Monoclonal↗
PubMed1997

A role for nuclear phosphatidylinositol-specific phospholipase C in the G2/M phase transition.

Protein kinase C (PKC) is activated at the nucleus during the G2 phase of cell cycle, where it is required for mitosis. However, the mechanisms controlling cell cycle-dependent activation of nuclear PKC are not known. We now report that nuclear levels of the major physiologic PKC activator diacylglycerol (DAG) fluctuate during cell cycle. Specifically, nuclear DAG levels in G2/M phase cells are 2. 5-3-fold higher than in G1 phase cells. In synchronized cells, nuclear DAG levels rise to a peak coincident with the G2/M phase transition and return to basal levels in G1 phase cells. This increase in DAG level is sufficient to stimulate betaII PKC-mediated phosphorylation of its mitotic nuclear envelope substrate lamin B in vitro. Isolated nuclei from G2 phase cells contain an active phospholipase activity capable of generating DAG in vitro. Nuclear phospholipase activity is inhibited by the selective phosphatidylinositol-specific phospholipase C (PI-PLC) inhibitor 1-O-octadeyl-2-O-methyl-sn-glycero-3-phosphocholine and neomycin sulfate, but not by the phosphatidylcholine-PLC selective inhibitor D609 or inhibitors of phospholipase D-mediated DAG generation. Treatment of synchronized cells with 1-O-octadeyl-2-O-methyl-sn-glycero-3-phosphocholine leads to decreased nuclear PI-PLC activity and cell cycle blockade in the G2 phase, suggesting a role for nuclear PI-PLC in the G2/M phase transition. Our data are consistent with the hypothesis that nuclear PI-PLC generates DAG to activate nuclear betaII PKC, whose activity is required for mitosis.

Cell Nucleus↗
PubMed1997

Effects of co-administration of butylated hydroxytoluene, butylated hydroxyanisole and flavonoids on the activation of mutagens and drug-metabolizing enzymes in mice.

Effects of co-administration of food additives and naturally occurring food components were studied on the activation of mutagens. Male mice (ddY) were given diets containing butylated hydroxytoluene (BHT) or butylated hydroxyanisole (BHA) and flavone or flavanone (2,3-dihydroflavone) for two weeks and the ability of hepatic microsomes to activate aflatoxin B1, benzo[a]pyrene and N-nitrosodimethylamine was determined by the mutagenicity test. Co-administration of an antioxidant (0.1% BHT or 0.2% BHA in diet) and a flavonoid (0.1% flavone or 0.1% flavanone) resulted in additive effects on the activation of aflatoxin B1 and benzo[a]pyrene, while the activation of N-nitrosodimethylamine was not elevated significantly by the co-administration. To understand the mechanism for the additive effects, induction of specific isozymes of cytochrome P450 involved in the activation of the mutagens was studied. Co-administration of BHT (0.1%) and flavone (0.1%) increased markedly the levels of proteins and the activities of the enzymes related to the isozymes of CYP2A and CYP2B, while co-administration of BHA (0.2%) and flavanone (0.1%) elevated those related to CYP1A. Further, the activation of aflatoxin B1 and benzo[a]pyrene in hepatic microsomes was inhibited by the antibodies against these isozymes, which suggested that the enhanced activation of the mutagens by the co-administration might be mediated by the induction of these isozymes.

Animals↗