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Biomedical subjects

X Yang

Publications and source records attributed to X Yang.

At least 883 records · Page 49Linked to original sources
PubMed1996

Ethanol exposure alters the phosphorylation of cyclic AMP responsive element binding protein and cyclic AMP responsive element binding activity in rat cerebellum.

The purpose of the present study was to track the acute effects of ethanol on the cerebellar adenylyl cyclase cascade from membrane to nucleus and to determine how this important signaling pathway neuroadapts during chronic ethanol exposure. An acute ethanol challenge increased cyclic AMP content and protein kinase A activity by 80% compared to control rats. In the nucleus the phosphorylated form of cAMP responsive element binding protein (CREB) increased 500%. Gel retardation assays with an oligomer encoding the rat proenkephalin cyclic AMP (CRE)1 were performed. Assays from protein derived from rats acutely exposed to ethanol identified three CRE-protein complexes also observed in assays of protein from saline-treated animals. However, after acute ethanol exposure, the intensity of the upper and middle CRE-protein complexes increased by 3-fold (280 +/- 10 vs. 70 +/- 3 arbitrary units; P < .01) compared to the sham treatment. Intensity of complex formation was still elevated 1 and 6 hr after ethanol exposure compared to sham conditions. In contrast, chronic ethanol treatment as well as pair-fed treatment did not alter the phosphorylation state of CREB or the intensity of the specific CRE-protein complexes on gel retardation assays. In summary, acute ethanol exposure resulted in the activation of the adenylyl cyclase signal transduction cascade from membrane to nucleus. In contrast, chronic ethanol exposure did not alter the phosphorylation of CREB or CRE binding activity. The behavioral significance of these events remain unclear, but may be related to the development of ethanol-induced tolerance in specific cerebellar functions.

Adenylyl Cyclases↗
PubMed1996

Structure of a Gelasinospora linear plasmid closely related to the kalilo plasmid of Neurospora intermedia.

We have determined the complete nucleotide sequence of a linear mitochondrial plasmid from a natural isolate of a homothallic species of Gelasinospora. The plasmid genome is 8231 bp long. It carries terminal inverted repeats of 1137 bp. Extending inwards from the terminal repeats are two long open reading frames coding for putative proteins with similarity to DNA and RNA polymerases. These are separated by a short intergenic region. The plasmid sequence shows remarkable similarity to that of the Neurospora intermedia senescence-plasmid kalilo. Overall the two plasmids have a similar genetic organization and are clearly homologous at the sequence level. The main differences are in the intergenic region and in the terminal repeats.

Amino Acid Sequence↗
PubMed1996

Attenuation of the expression of the focal adhesion kinase induces apoptosis in tumor cells.

The focal adhesion kinase (FAK) is a nonreceptor protein tyrosine kinase implicated in integrin-mediated signal transduction pathways, oncogenic transformation by v-src, and the invasion of human tumors. The overexpression of p125FAK in a variety of human tumors and tumor cell lines in comparison to their nontransformed counterparts suggested that attenuation of p125FAK expression might have an effect on tumor cell proliferation. In this study, we have treated tumor cell lines that expressed high levels of p125FAK with different antisense oligonucleotides to FAK, and have specifically attenuated p125FAK expression. The cells treated with antisense oligonucleotides not only lost their attachment, but also underwent apoptosis. Extensive control oligonucleotide experiments suggested that this attenuation was highly FAK specific. Furthermore, normal human fibroblasts, which did not express high levels of p125FAK, did not lose their attachment or become apoptotic with FAK antisense treatment. These results suggested that FAK is involved in adhesion-mediated growth in tumor cells and that FAK may be a rational gene-directed target for disrupting tumor cell growth.

Apoptosis↗
PubMed1996

T7-promoter-based Escherichia coli expression system induced with bacteriophage M13HEP.

The bacteriophage M13HEP was constructed by cloning the T7 RNA polymerase gene into phage M13mp18 RF DNA to express T7 RNA polymerase under the control of the lac promoter. Through M13HEP phage infection, T7 RNA polymerase could be introduced into an expression strain and heterologous genes under the control of the T7 promoter can be induced to express. Using this phage M13HEP induction system, many heterologous genes, especially some genes whose products are toxic to the host strain, were successfully expressed. By transferring F' pilli from E. coli XL1-blue to E. coli HMS174, a new E. coli strain HMS174F' was obtained to make the construction, expression, and single-stranded DNA rescue of the T7 expression plasmid be conveniently performed in the same strain.

Bacteriophage M13↗
PubMed1996

[Congenital anotia with hemifacial atrophy (a report of 12 cases)].

Twelve cases of congenital anotia with hemifacial atrophy were examined and analyzed with electromyogram and roentgenography. The results revealed that the development of the deformed side of the face was 30% less than the other side. Because both the soft tissue and the skeleton of the deformed side are undeveloped, they should be dealt with simultaneously.

Abnormalities, Multiple↗
PubMed1996

[Establishment of in vitro culture of bovine trabecular meshwork cells and their phagocytosis].

OBJECTIVE: To study the role of abnormality of phagocytosis of trabecular meshwork cells in the pathogenesis of glaucoma. METHOD: In vitro trabecular meshwork cell culture was successfully established from excised bovine aqueous outflow pathway. Using latex microspheres 0.6 micron in diameter as markers, we investigated the phagocytosis of cultured bovine trabecular cells and its influential factors qualitatively and quantitatively. RESULTS: Immunohistochemical staining studies have shown that trabecular cells secrete fibronectin and laminin. It is shown that bovine trabecular cells in vitro had strong phagocytic ability to ingest the particles, the number of latex beads in cells was increased with the prolongation of time in culture, and by 24 hours of incubation, the average number of beads in each cell was 40.5 +/- 6.7, in the mean time marked morphological and damaging changes, even death, of trabecular cells occurred. Epinephrine and cortisone inhibited significantly the phagocytosis of cells (P < 0.05), while epidermal growth factor had no such effect. CONCLUSION: The phagocytosis of trabecular cells is important to keep aqueous humour outflow patent, and abnormal phagocytosis of trabecular cells might be related to the pathogenesis of primary glaucoma.

Animals↗
PubMed1996

Abnormal expressions of hepatocellular proteins and extracellular matrix in CCL4-induced liver injury in rats.

OBJECTIVE: To evaluate the effects of carbon tetrachloride (CCl4) on the expressions of both intracellular proteins and extracellular matrix and the protective role of taurine. METHODS: Forty Sprague-Dawley rats were divided into five groups: 1.5% taurine, CCl4, CCl4 + 0.5% taurine, CCl4 + 1.5% taurine and control. CCl4 was given ig at a dose of 500 mg/kg body weight, twice a week for 5 weeks. The taurine solution or tap water was given to the rats for drinking. The sections (4 microns) of rat liver were stained with haematoxylin and eosin, immunohistochemistry or colloid silver methods. RESULTS: The animals treated with 1.5% taurine and control had normal liver structures. Light microscopic examination of sections of the liver taken 5 weeks after dosing of CCl4 showed hydropic degeneration of hepatocytes around the central veins and lipid vacuolation in mid-zonal and some periportal hepatocytes. Necrotic cells and neutrophil infiltration around most central veins as well as hepatocytes showing various stages of mitosis indicative of regeneration were observed. These histopathological changes in the animals treated with CCl4 alone showed more extensive and severe lesions than those seen in the animals treated with CCl4 plus taurines. The incidences of PCNA and p53 antigen positive hepatocytes, and the numbers of nuclear apoptotic bodies and AgNORs granules were markedly higher in the CCl4-treated animals than in those protected with taurine. Declined and unevenly distributed expressions of LN and FN were seen in the CCl4 treated rats. CONCLUSIONS: Both the damage of hepatocellular DNA and the abnormal expressions of hepatic extracellular matrix were observed in the CCl4-treated rats. Taurine, in this study, not only inhibited hepatocellular degeneration, necrosis and DNA damage, but also inhibited the lesion of extracellular matrix induced by CCl4.

Animals↗
PubMed1996

[The hepatitis A virus isolated and adapted in human diploid fibroblast cells (KMB17)].

Three hepatitis A virus (HAV) strains (L8, H32 and H52) were isolated from stool specimens of hepatitis A patients during an epidemic in 1988 in Shanghai and were adapted to grow in human diploid fibroblast cell strain (KMB17). The strains were serially carried through 10 passages in KMB17. The infectious titrations of these virus strains cultured for 28 days at the 10th passage were high up to 7.0-7.75 log TCID50/ml. The maximum virus yields occured in the 28th day after infection. Immune electronic microscopic studies revealed that the viral particles were 27-30 nm in diameter. The strains were neutralized by specific anti-HAV serum. Special fluorescent stained particles were observed clearly in the infected cellular plasma by direct IF. The above data suggest that the three strains are HAV and may be useful for further study.

Cell Line↗
PubMed1996

[Selective training of the vastus medialis muscle using electrical stimulator for chondromalacia patella].

Chondromalacia patella is closely related with subluxation and tilt of patella, as well as with muscular atrophy of quadriceps, especially in vastus medialis muscle. 364 cases of chondromalacia patella were treated with selective training of the vastus medialis muscle using electrical stimulator in our hospital. 211 cases were followed up after treatment from 6 months to 3 years. Among them excellent and good results were seen in 130 cases (62%), fair results were seen in 69 cases (33%) and no change was seen in 12 cases (5%). Significant reduction of CA (P < 0.01) and LPA (P < 0.001) were observed in all these patients in comparison with their primary angle. We believe that the selective training of the vastus medialis muscle using electrical stimulator is one of the effective methods for the treatment of chondromalacia patella.

Adult↗
PubMed1996

[Protective and treated effects of L-arginine on hypoxia-induced pulmonary hypertension in rats].

The protective and treated effects of L-Arginine on isobaric hypoxia-induced pulmonary hypertension were studied in rats. It was found that L-Arginine significantly inhibits hypoxic pulmonary hypertension and right ventricular hypertrophy. The mean pulmonary arterial pressure (mPAP) was 3.58 +/- 0.06 kPa and right ventricle/(left ventricle plus septum) ratio [RV/(LV+S)] was 0.34 +/- 0.01 in rats exposed to hypoxia (FiO2 = 0.10 +/- 0.05) for 3 weeks. The mPAP was 2.61 +/- 0.09 kPa and RV/(LV+S) was 0.26 +/- 0.01 in rats pretreated with L-Arginine [200mg/(kg.d)]i there is significant difference between the two groups. We also found that L-Arginine (300mg/kg) can decrease mPAP in rats with hypoxic pulmonary hypertension. The results suggest that L-Arginine might have significant protential for protection and treatment of hypoxic pulmonary hypertension.

Animals↗
PubMed1996

Laboratory evaluation on the toxic effects of bednets impregnated with permethrin against malaria mosquitos.

In the laboratory, bednets impregnated with 250mg ai/m2 and 500mg ai/m2 permethrin caused respectively the mean mortalities of 86.6% within 13 months and 87.2% within 17 months on laboratory-bred An. sinensis, while they caused average mortalities of 58.3% within 4 months and 73.8% within 10 months on An. dirus respectively. The bioassay results of KT50 and LT50 on the two species showed that KT50 is shorter than LT50 after exposure to the treated bednets. The ratio is 1:2.16 - 1:3.05. It was observed Anopheles had obviously secondary knocked down after exposure to the treated bednets and there is obvious resurgent after Anopheles have been knocked down. When the temperature goes up the resurgence gets shorter, the resurgence rate gets higher and the mortality gets lower. It showed that permethrin has stronger knocking down effect than killing effect.

Animals↗
PubMed1996

Structure and function of the band 3 Cl-/HCO3- transporter in chronic respiratory failure patients.

OBJECTIVE: To study red blood cell (RBC) membrane band 3 protein structure and anion transport function in cor pulmonale patients with respiratory failure. PATIENTS AND METHODS: Blood samples were obtained from 80 cases of cor pulmonale and 37 normal subjects (control group). The patients were divided into type I respiratory failure (Group I, n = 40) and type II respiratory failure (Group II, n = 40). The anion permeability of the erythrocyte membrane (Pcl), PO2 and PCO2 in 12 of the patients with type II respiratory failure were observed in acute stage (AS), chronic stage (CS) and recovery stage (RS). Membrane protein was analyzed by polyacrylamide electrophoresis in SDS. 55-KDa membrane domain was fractionated on 10% NaDodSO4 polyacrylamide gel column and purified further with a sephadax G-25 column. The composition of amino acids was analyzed on a Beckman 6300 Gold system amino acid analyzer. The Pcl was determined by the hypoisotonic hemolysis method. RESULTS: The relative content of band 3 protein erythrocytic membrane, anion permeability coefficient of the erythrocyte membrane and plasma chloride in the patients with cor pulmonale with type II respiratory failure were significantly lower than those in the patients with type I respiratory failure and the control. The number of residues in the anion transport domain of the trypsin fragment of 55,000 daltons of band 3 protein showed no significant difference among the three groups. CONCLUSIONS: The structure of anion transport sites remains intact and so the reduction of the anion transport function of band 3 protein in patients with cor pulmonale with type II respiratory failure may be due to the decrease of the relative content of band 3 protein, the decrease of extraerythrocytic chloride and hypoxia.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1996

Evaluation of glucose metabolic disorder: insulin resistance and insulin receptors in critically ill children.

OBJECTIVE: To explore the pathogenesis of glucose metabolic disorder and insulin resistance in critically ill children under severe stress. METHODS: To test glucose, lactate, glucagon, insulin, c-peptide, cortisol levels in 50 critically ill children. While we measured 125I-insulin binding to erythrocytes of 13 critically ill children who had hyperglycemia and hyperinsulinemia. Glucose and lactate were measured biochemically. Insulin, c-peptide, cortisol and glucagon were determined by RIA. Erythrocytes insulin receptor was detected by insulin radioreceptor assay. RESULTS: Glucose, lactate, insulin, c-peptide, glucagon, cortisol, insulin/glucose, insulin/glucagon ratio in patients were higher than those in normal controls (P < 0.05). As compared with normal controls, the maximum 125I-insulin bound and insulin receptor number per cell were significantly lower (P < 0.01). But there was no difference of mean value in receptor affinity (P > 0.05). CONCLUSIONS: Hyperglycemia is common in critically ill children during stress, which may be attributed to hormones disturbance and tissure insulin resistance. Insulin receptor defect due to comprehensive factors was one of the important causes for insulin resistance. The blood glucose level can be used as an predicting index in ICU.

Blood Glucose↗
PubMed1996

[Study on sister chromatid exchange in lymphocytes of women with fetal intrauterine growth retardation].

OBJECTIVE: To study sister chromatid exchange (SCE) frequency in lymphocytes of pregnant women with intrauterine growth retardation (IUGR) infants. METHODS: The frequency of SCE in peripheral blood lymphocytes of 14 pregnant women with IUGR babies and 90 normal pregnant women as well as the umbilical blood of their infants were investigated. RESULTS: The mean frequency of SCE in maternal and umbilical blood with normal pregnancy were 7.58 +/- 0.32 and 5.05 +/- 0.29 respectively, while they were 10.53 +/- 2.69 and 7.25 +/- 1.34 in IUGR group respectively. The difference of SCE levels between the 2 groups of mother was statistically significant (P < 0.01), so was that of the umbilical blood group. CONCLUSION: One of the causes of IUGR may be related to heredity injury. Thus, SCE will be a new diagnostic index to predict IUGR.

Adult↗
PubMed1996

[A study on interval of intravenous cyclophosphamide pulse in the treatment of severe systemic lupus erythematosus].

The aim of this study was to compare the clinical efficacy and adverse effects of intravenous cyclophosphamide pulse therapy between 2-week and 4-week intervals in the treatment of severe systemic lupus erythematosus. 52 patients were involved in the study and were equally divided into two groups. The pulse intervals were 2 weeks for group I and 4 weeks for group II. Each pulse dose of cyclophosphamide was 15 mg/kg. Every patient took prednisone 1 mg/kg daily for first 8 weeks and then tapered. Most of disease indices recovered quicker in group I than in group II. The group with short interval was better than that of long one on total efficacy and remission rate. The cyclophosphamide cumulative doses were not different between two groups as disease activity index dropped 50%. The pulse interval had to be prolonged from 2 weeks to 4 weeks to six patients in group I (23.1%) because of leukopenia, and be shortened from 4 weeks to 2 weeks to five cases in group II (19.2%) because of inefficacy. There was no statistical difference in adverse effects between two groups. Intravenous cyclophosphamide pulse therapy with two-weeks interval is advantageous to recovery of severe systemic lupus erythematosus provided blood test prior to each pulse. We suggest that pulse interval should be individualized.

Adolescent↗