[Care of broncho-biliary fistula caused by hydatidosis].
Explore the source record for details and available documents.
Echinococcosis, Pulmonary↗
Biomedical subjects
K Yang
Publications and source records attributed to K Yang.
Quantum ferromagnetism and phase transitions in double-layer quantum Hall systems.
Explore the source record for details and available documents.
Journal Article↗
Interference by complex structures of target DNA with specific PCR amplification.
It has been considered that target DNA is a forgiving component for PCR amplification. Herein we present evidence to demonstrate that secondary structure located at the end of a template may interfere with the specificity of amplification. Experiments indicate that nonspecific amplification results from a long stretch of stem and loop structures at the 3' end of prochymosin cDNA. Based on the sequence of mRNA coding for prochymosin, it is argued that the sequence responsible for the formation of the complex structure described here is most likely generated during synthesis of the second cDNA strand.
Base Sequence↗
Evidence for distinct isoforms of 11 beta-hydroxysteroid dehydrogenase in the ovine liver and kidney.
We have previously identified a unique 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) transcript in the ovine kidney. To examine whether this is indicative of a distinct isoform with respect to enzymatic activity, we studied and compared the characteristics of 11 beta-HSD activity in the ovine liver and kidney. 11 beta-HSD activity was determined by a radiometric conversion assay using cortisol and cortisone as physiological substrates. Although in both liver and kidney, the enzyme was localized by subcellular fractionation in the microsomes, the renal 11 beta-HSD displayed distinct characteristics in that it expressed only dehydrogenase activity and utilized almost exclusively NAD as cofactor (the respective activity in the presence of NAD and NADP was 190 +/- 26 and 12 +/- 2 pmol/min/mg protein). By contrast, the liver enzyme contained both dehydrogenase and reductase activities, and displayed preference for NADP and NADPH, respectively. Furthermore, with cortisol as substrate, the kidney 11 beta-HSD had a Km of 68 +/- 7 nM which was over 100 times lower than the hepatic enzyme (8 +/- 1 microM). In addition, the renal 11 beta-HSD activity was inhibited in a dose-dependent fashion by both carbenoxolone, a potent inhibitor of 11 beta-HSD, and the end product cortisone, whereas the liver enzyme showed little inhibition by either substance. In summary, these results provide strong evidence for the existence of distinct isoforms of 11 beta-HSD with respect to enzymatic activity in the ovine liver and kidney. In addition, the characteristics of the kidney enzyme closely resemble those of that described previously in the rabbit renal aldosterone target cells, and thus further demonstrating the presence of an isoform of 11 beta-HSD distinct from the NADP-dependent enzyme purified and cloned from the rat liver.
11-beta-Hydroxysteroid Dehydrogenases↗
Endogenous phosphorylation of a 61,000 dalton hippocampal protein increases following traumatic brain injury.
Acute biochemical consequences of moderate traumatic brain injury (TBI) include activation of kinases, including protein kinase C (PKC). To determine the possible consequences of PKC activation at the substrate level, we have examined protein phosphorylation patterns 1 h following injury. Although the phosphorylation of most proteins remained unchanged following injury, we observed a significant increase in the phosphorylation of a 61,000 dalton protein (TBI61) in injured rat hippocampus (121% higher than sham control) in vitro. TBI61 phosphorylation could be enhanced by phosphatidyl serine and diacylglycerol or by addition of exogenous PKC. In addition, TBI61 phosphorylation was inhibited by the PKC inhibitor, staurosporine, suggesting further that this protein may be a PKC substrate. These data suggest that TBI increases the phosphorylation of a 61 kD hippocampal protein in vitro. Increases in the protein level and activity of PKC could contribute to this increased phosphorylation.
Alkaloids↗
Aromatic DNA adducts in larynx biopsies and leukocytes.
Larynx cancer is strongly associated with tobacco smoking. The objective of this work was an analysis of aromatic DNA adducts in tumour and non-tumour larynx cells by means of the 32P-postlabelling method. Peripheral blood leukocytes were used as a reference tissue. The presence of aromatic DNA adducts was demonstrated in all the studied tissues obtained after surgery of larynx tumours. The highest level of DNA adducts was found in larynx tumour cells, followed by non-tumour larynx cells, which exceeded that found in leukocytes almost 2.5 times. Large interindividual differences were detected between subjects. The adduct level in tumour/non-tumour correlated only moderately. However a high correlation was found between the level of DNA adducts in larynx (tumour and non-tumour) cells and that in leukocytes.
Adult↗
Mammary ductal epithelial cell hyperproliferation and hyperplasia induced by a nutritional stress diet containing four components of a western-style diet.
We have studied effects of several nutrients on the proliferation of mammary ductal epithelial cells in C57BL/6J virgin female mice, using morphometry and [3H]dT in vivo labeling. A nutritional stress diet was given based on the AIN-76A semi-synthetic diet modified to contain four significant risk factors of a Western-style diet: high fat and phosphate and decreased calcium and vitamin D. The numbers of large, intermediate and terminal ducts and proliferating epithelial cells in mammary glands were assayed in control and stress diet groups. An increased number of mammary ducts and increased number of proliferating cells were found at the level of the small terminal ducts, a cancer-prone region in the mammary gland in the stress diet group compared to the control group after 20 weeks of diet administration. Thus, mammary terminal ductal hyperproliferation, expansion in the size of the proliferative epithelial cell compartment and excessive duplication of mammary ductal epithelial cells were found after this Western-style diet containing decreased dietary calcium and vitamin D. These changes are similar to those developing in colonic epithelium of mice maintained on the same diets and during chemically induced colonic carcinogenesis.
Animals↗
Cloning and characterization of polyketide synthase genes for jadomycin B biosynthesis in Streptomyces venezuelae ISP5230.
Hybridizing fragments in the genomic DNA of Streptomyces venezuelae ISP5230, which produces the jadomycin group of angucycline antibiotics, were detected by probing with actI DNA from Streptomyces coelicolor A3(2). The hybridizing regions were isolated from a 16.5 kb insert of S. venezuelae DNA recovered from a genomic library cloned in a lambda replacement vector. Subcloning and sequencing of a 4.8 kb segment of the insert, containing regions hybridizing to actIII as well as actI, identified five open reading frames (ORFs). The deduced polypeptide products of the ORFs closely resemble in sequence the components of streptomycete type-II polyketide synthases (PKSs): the ORF1 product corresponds to the ketoacyl synthase, and the ORF2 product to a polypeptide closely related to the ketoacyl synthase and involved in determining chain length; the ORF3 product matches the acyl carrier protein; ORF4 encodes a bifunctional cyclase/dehydrase; and ORF5 encodes a ketoreductase. Integration into the chromosomal DNA of a plasmid containing a segment of the ORF2-ORF4 region severely depressed jadomycin B biosynthesis; since the integrant showed no change in growth or spore pigmentation, the cloned PKS genes are presumed to encode enzymes in the pathway for jadomycin biosynthesis.
Amino Acid Sequence↗
Numerical study of the multiple-scattering series for gas-solid dynamics including single- through triple-collision terms.
Explore the source record for details and available documents.
Journal Article↗
Opposite effects of glucocorticoid on hepatic 11 beta-hydroxysteroid dehydrogenase mRNA and activity in fetal and adult sheep.
The level of 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) mRNA in the fetal sheep liver increases dramatically between day 130 and term (term = day 145), but the causal factors remain unknown. The present study was designed to determine the effects of exogenous glucocorticoid on the fetal hepatic 11 beta-HSD gene expression. Dexamethasone (dex; 2 micrograms/min over 15 min every 2 h) or saline was infused into chronically-catheterized fetal sheep at day 130 of gestation for 4 days. At the end of infusion, the lower right lobe of the liver was collected, total cellular RNA extracted and subjected to Northern blot analysis. It was found that the level of the hepatic 11 beta-HSD mRNA in dex-treated fetuses was about four times higher than that in the saline-treated controls. To examine whether changes occur in the response of hepatic 11 beta-HSD gene expression to glucocorticoids in adulthood, we also treated non-pregnant ewes with dex (10 mg/day) for 4 days. By contrast, this treatment regime in adult sheep produced a small but significant decrease in hepatic 11 beta-HSD mRNA levels. We also determined whether age-specific changes in the hepatic level of 11 beta-HSD mRNA following dex treatment were reflected in the level of 11 beta-HSD enzyme activity. Hepatic 11 beta-HSD activity was determined by a standard in vitro conversion assay using cortisol and cortisone as physiological substrates. In both fetal and adult livers, 11-oxoreductase activity (cortisone-->cortisol) was predominant.(ABSTRACT TRUNCATED AT 250 WORDS)
11-beta-Hydroxysteroid Dehydrogenases↗
Regulation of ovine fetal pituitary function by corticotrophin-releasing hormone, arginine vasopressin and cortisol in vitro.
Parturition and fetal organ maturation in sheep are associated with increased activity of the fetal hypothalamic-pituitary-adrenal (HPA) axis during late pregnancy. However, the factors responsible for HPA activation remain unclear. In the fetal pituitary, levels of pro-opiomelanocortin (POMC) mRNA increase, but the numbers of binding sites for corticotrophin-releasing hormone (CRH), and ACTH responsiveness to exogenous CRH decline during the last 20 days of pregnancy. We have examined regulation of CRH binding, pituitary ACTH responsiveness, and levels of POMC mRNA in cultures of adenohypophysial cells from term fetal sheep. After a 4-day stabilization period, output of immunoreactive (ir) ACTH was increased over 48 h in a dose-dependent fashion by both CRH and arginine vasopressin (AVP) but decreased by cortisol. Subsequent output of ir-ACTH to a 3-h challenge with 100 nM CRH was attenuated after pretreatments with CRH, AVP or cortisol; the effect of CRH being greater than that of cortisol or AVP. At the end of 48 h of treatment with CRH, AVP or cortisol, there was a 40-50% reduction in the number of CRH-binding sites, but the levels of POMC mRNA decreased significantly only after cortisol treatment and were not altered significantly by CRH or AVP. We conclude that under the conditions of these experiments, CRH and AVP increase ir-ACTH output without increasing the level of steady-state POMC mRNA, but may contribute to loss of pituitary responsiveness to CRH by down-regulation of CRH receptor number. Cortisol exerts negative feedback on POMC mRNA and decreases the number of CRH receptors. Thus, any one or all of CRH, AVP and cortisol could be responsible for the decline in CRH binding in the fetal sheep pituitary during late pregnancy. Although CRH and AVP may affect secretion of ir-ACTH, the present results do not support a role for these neuropeptides in affecting the level of POMC mRNA in the fetal sheep pituitary.
Adrenocorticotropic Hormone↗
[High-dose cytarabine as intensive postremission therapy in acute myelogenous leukemia: effect on long-term disease-free survival].
In an attempt to increase the proportion of patients with acute myelogenous leukemia (AML) remaining in long-term disease-free survival (DFS). 37 patients with AML in complete remission (CR) received HD-Ara-C (1.0 g/m2) as intensive postremission therapy. The results were compared with those of 28 patients who did not receive HD-Ara-C therapy (control group) during the same period. With a median follow-up of 21.7 months (6.9-77.3), median CR duration was 16.0 months for HD-Ara-C group and 10.0 months (2.0-75.2) for the control group. Relapse rates were 48.6% (18/37) and 75% (21/28), respectively. The actuarial 3 and 5 years DFS was 50.2% and 43% for HD-Ara-C group versus 31% and 16.7% for the control group. There was significant difference (P < 0.05). This result suggested that HD-Ara-C could prolong DFS and reduce relapse in patients with AML.
Adolescent↗
Expression and secretion of glucoamylase of Aspergillus niger in Saccharomyces cerevisiae.
Glucoamylase cDNA synthesized from A. niger mutant T21 was modified at 5' and 3' ends in order to clone it into yeast shuttle plasmid YFD18 and to cause fusion between cDNA and the leader region of the yeast-mating pheromone alpha-factor. The modified cDNA was then inserted into YFD18 at HindIII site. Saccharomyces cerevisiae Y33 was transformed with the resultant recombinant plasmid YFD18HH6. Analysis of transformants including halo formation on starch medium plate, SDS-PAGE of culture filtration and determination of glucoamylase activity showed that the yeast transformed with plasmid containing glucoamylase cDNA efficiently secreted glucoamylase into the medium. This fact indicated that yeast alpha-factor was able to direct the synthesis and secretion of functional glucoamylase of Aspergillus. In addition the protolytic cleavage site involved in the maturation of glucoamylase in A. niger also worked in S. cerevisiae.
Aspergillus niger↗
[Acute leukemia: autologous transplantation of bone marrow cells grown in long-term culture containing low molecular weight natural tumour suppressor].
Fourteen patients with acute myelogenous leukemia and 3 patients with acute lymphoblastic leukemia in complete remission underwent autologous transplantation of their bone marrow cells in long-term culture containing low molecular weight-natural tumour suppressor. Their mean age was 27 years (9-35). Preparative regimen included cyclophosphamide and total body irradiation. All patients received no chemotherapy after transplantation. Follow-up for to 45 months showed that 11 patients remained disease-free survival (DFS) at 15 months, 8 at 24 months, 5 at 30 months, and 1 at 43 months. 5 patients relapsed between 6 and 22 months. One case died from sudden death at 6 months. 3.5-year DFS was 62.7 +/- 15.0%.
Adolescent↗
[Isolation and sequencing of glucoamylase gene from a glucoamylase over producing strain].
Chromosomal DNA was isolated from the mycelia of Aspergillus niger T21, a strain producing glucoamylase at a high level. Southern blot analysis indicated that the glucoamylase gene is situated on a 2.5kb EcoR I -EcoR V fragment. Chromosomal DNA was digested completely with EcoR I, EcoR V. The fragments in the range of 2.0-3.0kb were isolated through electrophoresis in agarose gel. The pooled fragments were ligated onto pBR322 vector prior to transformation into E. coli DH5. Four glucoamylase-specific recombinants were screened by in situ hybridization from the transformants. Restriction mapping and sequencing for one of the four were performed. Data show that the glucoamylase gene from A. niger T21 is a 2.3kb fragment containing four intervening sequences in the coding region.
Aspergillus niger↗
Synthesis, characterization, and antioxidative activity of new vitamin B6 triethanolamine rare earth (III) complexes.
A series of new vitamin B6 triethanolamine rare earth (III) complexes Re(PN)3(TEA)(NO3)2Cl (PN = pyridoxol; TEA = triethanolamine; Re = La1, Ce2, Pr3, Nd4, Sm5, Tb6, Dy7, Ho8, Er9, Y10), were synthesized and characterized by elemental analysis, molar conductance, TGA-DTA, UV, IR, and 1H NMR spectroscopic techniques. The suppression ratio of complexes for the hydroxyl radical (OH.) and the superoxide radical (O2-.) were determined, the results show that these complexes possess scavenging effects on OH. and O2(-.). In this paper we also discuss the effect of complex conc. for the suppression ratio on superoxide radical O2(-.).
Antioxidants↗
Synthesis, characterization, and antioxidative activity of vitamin B6 rare earth (III) complexes.
A series of vitamin B6 pyridoxol rare earth (III) complexes Re(PN)5Cl3. 6H2O (PN = pyridoxol; Re = La, Ce, Pr, Nd, Sm, Eu, Gd, Ho, Er, Y) were synthesized and characterized by elemental analysis, molar conductance, TGA-DTA, IR, and 1HNMR spectroscopic techniques. The antioxidative activity of complexes was determined, using the suppression ratio of activated oxygen as an indicator. The results show that the complexes have the scavenger effects for activated oxygen.
Antioxidants↗
Effects of low dose transdermal scopolamine on heart rate variability in acute myocardial infarction.
OBJECTIVES: We hypothesized that by enhancing parasympathetic activity, low dose transdermal scopolamine would increase heart rate variability after myocardial infarction. BACKGROUND: Low heart rate variability is associated with increased mortality after acute myocardial infarction. METHODS: Conventional time domain heart rate variability was measured from 24-h Holter recordings of 61 consecutive male patients (mean age 58 +/- 10 years, left ventricular ejection fraction 44.7 +/- 15.5%) 6 days (median) after acute myocardial infarction. Patients were then randomly assigned to wear one patch of transdermal scopolamine or a matching placebo patch for 24 h, during which their 24-h heart rate variability was remeasured. RESULTS: Compared with placebo, transdermal scopolamine caused a significant increase in time domain measures of 24-h heart rate variability by 26% to 35% above baseline. Transdermal scopolamine was well tolerated. CONCLUSIONS: Low dose transdermal scopolamine safely increases cardiac parasympathetic activity and short-term heart rate variability after acute myocardial infarction. Whether the effect of transdermal scopolamine on heart rate variability is a reasonable surrogate for improvement of long-term morbidity and mortality requires an appropriate designed investigation.
Administration, Cutaneous↗